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1.
Clin Neurophysiol ; 129(9): 1813-1818, 2018 09.
Article in English | MEDLINE | ID: mdl-29981956

ABSTRACT

OBJECTIVE: To assess residual retinal ganglion cell (RGC) function in patients with recovered optic neuritis (ON) and multiple sclerosis (MS). METHODS: Age-matched controls (C, n = 32) and MS patients (n = 17) with history of ON in one eye but normal visual acuity and color vision were tested with steady-state Pattern Electroretinogram (PERG). Light Emitting Diodes (LED)-generated bar gratings, robust signal averaging and Fourier analysis were used to assess response amplitude and latency. RESULTS: PERG amplitude was similar for C, ON and fellow eyes (FE) (P = 0.4), but PERG latency was shortened in ON by 3.2 ms (P = 0.002) and in FE by 2.0 ms (P = 0.02) and was correlated (P < 0.01) with both Retinal Nerve Fiber Layer (RNFL) and Ganglion Cell Inner Plexiform Layer (GCIPL) thicknesses. PERG latency shortening could be simulated in control subjects (n = 8) by dioptrically blurring the edges of gratings (high spatial frequencies), which reduced activity of parvocellular RGCs with smaller/slower axons. The blurred PERG latency was shorter than baseline by 2.9 ms (P = 0.01). CONCLUSIONS: PERG latency is shortened in both eyes of MS patients with recovered unilateral ON, suggesting relative dysfunction of RGCs with slower axons and sparing of RGCs with faster axons. SIGNIFICANCE: Assessment of PERG latency in MS and ON may help identifying and monitoring RGC dysfunction. PERG latency shortening in FE suggests primary retinopathy in MS.


Subject(s)
Multiple Sclerosis/physiopathology , Optic Neuritis/physiopathology , Recovery of Function/physiology , Retina/physiopathology , Retinal Ganglion Cells/physiology , Adult , Electroretinography , Female , Humans , Male , Middle Aged
3.
J Gastrointest Surg ; 22(1): 124-132, 2018 01.
Article in English | MEDLINE | ID: mdl-28808892

ABSTRACT

BACKGROUND: We evaluated long-term incidence and identified risk factors of colectomy in pre-biologics and biologics eras for treatment of ulcerative colitis. METHODS: After IRB approval, using data obtained from the Régie d'assurance maladie du Québec, we defined two cohorts: pre-biologics (1998-2004) and biologics (2005-2011) eras. Patients with inflammatory bowel disease or colectomy 1 year prior to first diagnosis of ulcerative colitis were excluded. Multivariate logistic regression model compared patient baseline characteristics. Kaplan-Meier curves displayed unadjusted time to event. Cox proportional hazards models were used to compare adjusted colectomy and mortality rates, respectively. RESULTS: In pre-biologics and biologics eras, 335/2829 and 314/3313 patients, respectively, underwent colectomy. Median follow-up (first and third quartiles) was similar (p = 0.206). Incidence rates for colectomy were 36.08/1000 and 29.99/1000 patient years. Unadjusted rate of colectomy was higher in pre-biologics era (p = 0.004). Predictors of colectomy included anemia (1.66; 1.38-2.01), gastrointestinal hospitalizations (1.24; 1.04-1.47), congestive heart failure (2.08; 1.27-3.40), and male gender (1.47; 1.26-1.72). Mortality was 8.06 and 3.18% in pre-biologics and biologics eras. After adjusting for potential confounders, age (1.08; 1.05-1.12) and urgent colectomy (5.65; 2.19-14.54) remained associated with increased mortality hazard. CONCLUSION: Incidence of colectomy decreased after introduction of biologics. Risk factors for colectomy were gastrointestinal hospitalizations, anemia, male gender, and congestive heart failure. Emergent surgery and age were predictors of mortality.


Subject(s)
Biological Products/therapeutic use , Colectomy/statistics & numerical data , Colitis, Ulcerative/drug therapy , Colitis, Ulcerative/surgery , Adult , Age Factors , Aged , Anemia/epidemiology , Colitis, Ulcerative/mortality , Emergencies/epidemiology , Female , Heart Failure/epidemiology , Hospitalization , Humans , Interrupted Time Series Analysis , Male , Middle Aged , Proportional Hazards Models , Quebec/epidemiology , Risk Factors , Sex Factors
4.
Dis Colon Rectum ; 60(7): 729-737, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28594723

ABSTRACT

BACKGROUND: Recent studies demonstrated reduced postoperative complications using combined mechanical bowel and oral antibiotic preparation before elective colorectal surgery. OBJECTIVE: The aim of this study was to assess the impact of these 2 interventions on surgical site infections, anastomotic leak, ileus, major morbidity, and 30-day mortality in a large cohort of elective colectomies. DESIGN: This is a retrospective comparison of 30-day outcomes using the American College of Surgeons National Surgical Quality Improvement Program colectomy-targeted database with coarsened exact matching. SETTINGS: Interventions were performed in hospitals participating in the national surgical database. PATIENTS: Adult patients who underwent elective colectomy from 2012 to 2014 were included. INTERVENTIONS: Preoperative bowel preparations were evaluated. MAIN OUTCOME MEASURES: The primary outcomes measured were surgical site infections, anastomotic leak, postoperative ileus, major morbidity, and 30-day mortality. RESULTS: A total of 40,446 patients were analyzed: 13,219 (32.7%), 13,935 (34.5%), and 1572 (3.9%) in the no-preparation, mechanical bowel preparation alone, and oral antibiotic preparation alone groups, and 11,720 (29.0%) in the combined preparation group. After matching, 9800, 1461, and 8819 patients remained in the mechanical preparation, oral antibiotic preparation, and combined preparation groups for comparison with patients without preparation. On conditional logistic regression of matched patients, oral antibiotic preparation alone was protective of surgical site infection (OR, 0.63; 95% CI, 0.45-0.87), anastomotic leak (OR, 0.60; 95% CI, 0.34-0.97), ileus (OR, 0.79; 95% CI, 0.59-0.98), and major morbidity (OR, 0.73; 95% CI, 0.55-0.96), but not mortality (OR, 0.32; 95% CI, 0.08-1.18), whereas a regimen of combined oral antibiotics and mechanical bowel preparation was protective for all 5 major outcomes. When directly compared with oral antibiotic preparation alone, the combined regimen was not associated with any difference in any of the 5 postoperative outcomes. LIMITATIONS: This study was limited by its retrospective design with heterogeneous data. CONCLUSIONS: Oral antibiotic preparation alone significantly reduced surgical site infection, anastomotic leak, postoperative ileus, and major morbidity after elective colorectal surgery. A combined regimen of oral antibiotics and mechanical bowel preparation offered no superiority when compared with oral antibiotics alone for these outcomes. See Video Abstract at http://links.lww.com/DCR/A358.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Antibiotic Prophylaxis/methods , Cathartics/therapeutic use , Colectomy/methods , Colorectal Neoplasms/surgery , Diverticulitis, Colonic/surgery , Inflammatory Bowel Diseases/surgery , Postoperative Complications/epidemiology , Administration, Oral , Adult , Aged , Anastomotic Leak/epidemiology , Elective Surgical Procedures/methods , Female , Humans , Ileus/epidemiology , Logistic Models , Male , Middle Aged , Mortality , Multivariate Analysis , Preoperative Care , Retrospective Studies , Surgical Wound Infection/epidemiology
5.
Dis Colon Rectum ; 59(7): 648-55, 2016 Jul.
Article in English | MEDLINE | ID: mdl-27270517

ABSTRACT

BACKGROUND: Initial nonoperative management of diverticular abscess has become the standard of care; however, the need for elective resection after this index episode is unclear. OBJECTIVE: The purpose of this study was to assess the long-term outcomes of expectant management after initial nonoperative treatment of diverticular abscess. DESIGN: This was a retrospective chart review with prospective telephone follow-up of patients. SETTINGS: The study was conducted at a large tertiary academic colorectal surgery practice in Canada. PATIENTS: Adult patients with CT-documented acute sigmoid diverticulitis complicated by abscess managed nonoperatively from 2000 to 2013 were included. INTERVENTIONS: Long-term definitive nonoperative management of diverticular abscess. MAIN OUTCOME MEASURES: The primary outcome was emergency sigmoidectomy or death from recurrent diverticulitis. Secondary outcomes were recurrent diverticulitis and elective sigmoidectomy for diverticulitis. RESULTS: Of 135 patients with acute diverticulitis complicated by abscess, a total of 73 patients were managed with nonoperative intent and long-term expectant management. The median follow-up was 62 (Q1 to Q3: 28-98) months. After resolution of the index episode, 22 patients [30.1% (95% CI, 19.6%-40.6%)] experienced a recurrent episode of diverticulitis at a median of 23 (range, 9-40) months. Two patients [2.7% (95% CI, -1.0% to 6.4%)] had a recurrent episode with peritonitis that required sigmoidectomy with stoma at 6 and 64 months. Both patients underwent reversal after 4 and 8 months. Seven [9.6% (95% CI, 2.8%-16.4%)] patients experienced a complicated recurrence and underwent an elective sigmoidectomy [median time to colectomy, 33 (range, 16-56) months]. Thirteen patients [17.8% (95% CI, 9.0%-26.6%)] experienced an uncomplicated recurrence, all of whom were managed with continued nonoperative intent [median follow-up, 81 (range, 34-115) months]. No mortality occurred. On multivariate logistic regression, female gender (p = 0.048) and a previous episode of uncomplicated diverticulitis before the index diverticular abscess (p = 0.020) were associated with a recurrent episode. LIMITATIONS: This study was limited by its retrospective design and modest sample size. CONCLUSIONS: After initial successful nonoperative management of diverticulitis with abscess, expectant management with nonoperative intent is a safe long-term option with low rates of surgery, especially in the emergency setting. See Video, Supplemental Digital Content 1, on the nonoperative management of diverticular abscess at http://links.lww.com/DCR/A234.


Subject(s)
Abdominal Abscess/therapy , Aftercare/methods , Diverticulitis, Colonic/complications , Sigmoid Diseases/complications , Watchful Waiting , Abdominal Abscess/etiology , Aged , Colectomy , Diverticulitis, Colonic/diagnostic imaging , Diverticulitis, Colonic/mortality , Diverticulitis, Colonic/therapy , Female , Follow-Up Studies , Humans , Logistic Models , Male , Middle Aged , Prospective Studies , Recurrence , Retrospective Studies , Sigmoid Diseases/diagnostic imaging , Sigmoid Diseases/mortality , Sigmoid Diseases/therapy , Treatment Outcome
6.
Can J Surg ; 59(1): 54-8, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26812410

ABSTRACT

ABSTRACT: This review is intended to raise awareness of placing a pelvic mesh to prevent perineal hernias in cases of minimally invasive (MIS) abdominoperineal resections (APR) and, in doing so, causing internal hernias through the mesh. In this article, we review the published literature and present an illustrative series of 4 consecutive cases of early internal hernia through a pelvic mesh defect. These meshes were placed to prevent perineal hernias after laparoscopic or robotic APRs. The discussion centres on 3 key questions: Should one be placing a pelvic mesh following an APR? What are some of the technical details pertaining to the initial mesh placement? What are the management options related to internal hernias through such a mesh?


RESUME: L'objectif du présent examen est de sensibiliser les praticiens au risque associé à la pose d'un treillis pelvien visant à prévenir les hernies périnéales après une résection abdominopérinéale à effraction minimale, pratique qui peut entraîner une hernie interne. Nous nous penchons ici sur les articles publiés à ce sujet et présentons une série éloquente de 4 cas consécutifs de hernies internes précoces attribuables à un défaut du treillis. Les dispositifs avaient été mis en place pour prévenir une hernie périnéale après des résections laparoscopiques ou robotiques. La discussion porte sur 3 questions centrales : Devrait-on poser un treillis pelvien à la suite d'une résection abdominopérinéale? Quels sont les éléments techniques à surveiller lors de la pose initiale? Quelles sont les options de prise en charge des hernies internes causées par les treillis?


Subject(s)
Digestive System Surgical Procedures/adverse effects , Incisional Hernia/prevention & control , Laparoscopy/adverse effects , Perineum/surgery , Surgical Mesh/adverse effects , Aged, 80 and over , Female , Humans , Incisional Hernia/etiology , Male , Middle Aged
7.
Dis Colon Rectum ; 59(2): 101-9, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26734967

ABSTRACT

BACKGROUND: The management of acute diverticulitis in immunosuppressed patients is increasingly debated. The appropriate timing and type of operation remains controversial. OBJECTIVE: This study examines the impact of immunosuppression on mortality and morbidity following colectomies for diverticulitis in the emergency and elective settings. DESIGN SETTINGS: With the use of the American College of Surgeons National Surgical Quality Improvement Program database, the outcomes of immunosuppressed compared with immunocompetent patients who underwent colectomy for acute diverticulitis were compared. PATIENTS: The multi-institutional database was queried for patients who underwent colectomy for acute diverticulitis from 2005 to 2012. MAIN OUTCOMES MEASURES: The impact of immunosuppression on mortality, major morbidity, organ space infection, infectious complications, and wound dehiscence was assessed. RESULTS: Of 26,987 patients, 1332 were immunosuppressed and 25,655 were immunocompetent; 4271 patients had emergency (596 immunosuppressed and 3675 immunocompetent) and 22,716 patients had elective (736 immunosuppressed and 21,980 immunocompetent) colectomies for diverticulitis. In both groups, mortality and major morbidity were significantly higher in the emergency (immunosuppressed 16% and 45%, immunocompetent 4% and 28%) compared with the elective setting (immunosuppressed 2% and 25%, immunocompetent 0.4% and 12%), p < 0.001. On multivariate regression for the emergency setting, immunosuppression significantly increased mortality (OR, 1.79; 95% CI, 1.17-2.75) and did not significantly increase morbidity. On multivariate regression for the elective setting, mortality was similar in immunosuppressed and immunocompetent groups; however, major morbidity (OR, 1.46; 95% CI, 1.17-1.83) and wound dehiscence (OR, 2.69; 95% CI, 1.63-4.42) were significantly increased in immunosuppressed compared with immunocompetent patients. LIMITATIONS: The retrospective design and standardized outcomes are based on heterogeneous data. CONCLUSIONS: Emergency colectomy for diverticulitis is associated with higher mortality in immunosuppressed than in immunocompetent patients, whereas elective colectomy is associated with comparable mortality. In the elective setting, immunosuppressed compared with immunocompetent patients are at increased risk of major morbidity and wound dehiscence.


Subject(s)
Colectomy , Colon, Sigmoid , Diverticulitis, Colonic , Immune Tolerance , Surgical Wound Infection , Acute Disease , Aged , Colectomy/adverse effects , Colectomy/methods , Colon, Sigmoid/pathology , Colon, Sigmoid/surgery , Databases, Factual , Diverticulitis, Colonic/diagnosis , Diverticulitis, Colonic/immunology , Diverticulitis, Colonic/mortality , Diverticulitis, Colonic/surgery , Emergency Medical Services/methods , Emergency Medical Services/statistics & numerical data , Female , Humans , Male , Middle Aged , Quebec/epidemiology , Risk Factors , Surgical Wound Infection/epidemiology , Surgical Wound Infection/etiology , Treatment Outcome
8.
J Neurosci Methods ; 261: 97-109, 2016 Mar 01.
Article in English | MEDLINE | ID: mdl-26719239

ABSTRACT

BACKGROUND: Computationally efficient spike recognition methods are required for real-time analysis of extracellular neural recordings. The enteric nervous system (ENS) is important to human health but less well-understood with few appropriate spike recognition algorithms due to large waveform variability. NEW METHOD: Here we present a method based on dynamic time warping (DTW) with high tolerance to variability in time and magnitude. Adaptive temporal gridding for "fastDTW" in similarity calculation significantly reduces the computational cost. The automated threshold selection allows for real-time classification for extracellular recordings. RESULTS: Our method is first evaluated on synthesized data at different noise levels, improving both classification accuracy and computational complexity over the conventional cross-correlation based template-matching method (CCTM) and PCA+k-means clustering without time warping. Our method is then applied to analyze the mouse enteric neural recording with mechanical and chemical stimuli. Successful classification of biphasic and monophasic spikes is achieved even when the spike variability is larger than millisecond in width and millivolt in magnitude. COMPARISON WITH EXISTING METHOD(S): In comparison with conventional template matching and clustering methods, the fastDTW method is computationally efficient with high tolerance to waveform variability. CONCLUSIONS: We have developed an adaptive fastDTW algorithm for real-time spike classification of ENS recording with large waveform variability against colony motility, ambient changes and cellular heterogeneity.


Subject(s)
Action Potentials , Algorithms , Neurons/physiology , Pattern Recognition, Automated/methods , Wavelet Analysis , Animals , Cluster Analysis , Mice, Inbred C57BL , Microelectrodes , Muscle, Smooth/physiology , Myenteric Plexus/physiology , Physical Stimulation , Principal Component Analysis , Signal Processing, Computer-Assisted , Time Factors , Tissue Culture Techniques
9.
J Gastrointest Surg ; 19(6): 1106-12, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25859755

ABSTRACT

BACKGROUND: Recent attention has been focused on the relationship between carcinoembryonic antigen (CEA) and pathological complete response (pCR), without consensus regarding its predictive value. This study aims to examine the association between CEA and pCR. METHODS: We conducted a retrospective review of a prospectively maintained database of all patients who underwent primary rectal cancer resection after neo-adjuvant chemoradiotherapy (nCRT). Patients were divided into two groups, pCR or no-pCR, based on final pathology. CEA levels were measured at the initial visit with the surgeon/oncologist and post-completion of nCRT. RESULTS: One hundred and forty-one patients underwent primary rectal cancer resections after nCRT. Nineteen patients (13.5 %) achieved pCR, while 122 (86.5 %) had no-pCR. Pre-nCRT CEA levels were not significantly different between groups (2.75 vs 4.5 µg/L, p = 0.65). However, post-nCRT CEA levels were significantly lower in patients with pCR (1.7 vs 2.4 µg/L, p < 0.01). On multivariate logistic regression analyses, low post-nCRT CEA level was an independent predictor of pCR (OR 1.74, CI 1.06, 3.81) and normalization of CEA from an initially elevated level was a highly significant predictor of pCR (OR 64.8, CI 2.53, 18,371). CONCLUSION: Low post-nCRT CEA is an independent predictor of pCR, and normalization of CEA post-nCRT is a strong predictor of pCR.


Subject(s)
Adenocarcinoma/blood , Carcinoembryonic Antigen/blood , Rectal Neoplasms/blood , Adenocarcinoma/pathology , Adenocarcinoma/therapy , Adult , Aged , Biomarkers, Tumor/blood , Chemoradiotherapy, Adjuvant , Disease Progression , Female , Humans , Male , Middle Aged , Neoplasm Staging , Rectal Neoplasms/pathology , Rectal Neoplasms/therapy , Retrospective Studies , Treatment Outcome
10.
World J Gastroenterol ; 20(33): 11486-95, 2014 Sep 07.
Article in English | MEDLINE | ID: mdl-25206256

ABSTRACT

This review of the literature on small bowel carcinoma associated with Crohn's disease specifically addresses the incidence, risk factors, and protective factors which have been identified. It also reviews the clinical presentation, the current modalities of diagnosis, the pathology, treatment, and surveillance. Finally, the prognosis and future direction are addressed. Our experience with small bowel adenocarcinoma in Crohn's disease is reported. Readers will be provided with a better understanding of this rare and often poorly recognized complication of Crohn's disease.


Subject(s)
Adenocarcinoma/epidemiology , Crohn Disease/epidemiology , Intestinal Neoplasms/epidemiology , Intestine, Small , Adenocarcinoma/diagnosis , Adenocarcinoma/therapy , Crohn Disease/diagnosis , Crohn Disease/therapy , Humans , Incidence , Intestinal Neoplasms/diagnosis , Intestinal Neoplasms/therapy , Intestine, Small/drug effects , Intestine, Small/pathology , Intestine, Small/surgery , Predictive Value of Tests , Prognosis , Protective Factors , Risk Assessment , Risk Factors
11.
Nutr J ; 12(1): 145, 2013 Nov 09.
Article in English | MEDLINE | ID: mdl-24206944

ABSTRACT

BACKGROUND: 25(OH) vitamin D levels may be low in patients with moderately or severely active inflammatory bowel diseases (IBD: Crohn's disease and Idiopathic Ulcerative Colitis) but this is less clear in patients with mild or inactive IBD. Furthermore there is limited information of any family influence on 25(OH) vitamin D levels in IBD. As a possible risk factor we hypothesize that vitamin D levels may also be low in families of IBD patients. OBJECTIVES: To evaluate 25[OH] vitamin D levels in patients with IBD in remission or with mild activity. A second objective is to evaluate whether there are relationships within IBD family units of 25[OH] vitamin D and what are the influences associated with these levels. METHODS: Participants underwent medical history, physical examination and a 114 item diet questionnaire. Serum 25[OH] vitamin D was measured, using a radioimmunoassay kit, (replete ≥ 75, insufficient 50-74, deficient < 25-50, or severely deficient < 25 nmol/L). Associations between 25[OH] vitamin D and twenty variables were evaluated using univariate regression. Multivariable analysis was also applied and intrafamilial dynamics were assessed. RESULTS: 55 patients and 48 controls with their respective families participated (N206). 25[OH] vitamin D levels between patients and controls were similar (71.2 ± 32.8 vs. 68.3 ±26.2 nmol/L). Vitamin D supplements significantly increased intake but correlation with serum 25[OH] vitamin D was significant only during non sunny months among patients. Within family units, patients' families had mean replete levels (82.3 ± 34.2 nmol/L) and a modest correlation emerged during sunny months between patients and family (r2 =0.209 p = 0.032). These relationships were less robust and non significant in controls and their families. CONCLUSIONS: In patients with mild or inactive IBD 25[OH] vitamin D levels are less than ideal but are similar to controls. Taken together collectively, the results of this study suggest that patient family dynamics may be different in IBD units from that in control family units. However contrary to the hypothesis, intra familial vitamin D dynamics do not pose additional risks for development of IBD.


Subject(s)
Dietary Supplements , Inflammatory Bowel Diseases/blood , Vitamin D/administration & dosage , Vitamin D/blood , Adolescent , Adult , Aged , Body Mass Index , C-Reactive Protein/metabolism , Case-Control Studies , Child , Female , Ferritins/blood , Humans , Linear Models , Male , Middle Aged , Multivariate Analysis , Nutrition Assessment , Risk Factors , Seasons , Young Adult
12.
Article in English | MEDLINE | ID: mdl-23944512

ABSTRACT

Electrochemical gating is the process by which an electric field normal to the insulator electrolyte interface shifts the surface chemical equilibrium and further affects the charge in solution [Jiang and Stein, Langmuir 26, 8161 (2010)]. The surface chemical reactivity and double-layer charging at the interface of electrolyte-oxide-semiconductor (EOS) capacitors is investigated. We find a strong pH-dependent hysteresis upon dc potential cycling. Varying salinity at a constant pH does not change the hysteretic window, implying that field-induced surface pH regulation is the dominant cause of hysteresis. We propose and investigate this mechanism in foundry-made floating-gate ion-sensitive field-effect transistors, which can serve as both an ionic sensor and an actuator. Termed the chemoreceptive neuron metal-oxide-semiconductor (CνMOS) transistor, it features independently driven control gates (CGs) and sensing gates (SGs) that are capacitively coupled to an extended floating gate (FG). The SG is exposed to fluid, the CG is independently driven, and the FG is capable of storing charge Q(FG) of either polarity. Asymmetric capacitive coupling between the CG and SG to FG results in intrinsic amplification of the measured surface potential shifts and influences the FG charge injection mechanism. This modified SG surface condition was monitored through transient recordings of the output current, performed under alternate positive and negative CG pulses. Transient recordings revealed a hysteresis where the current was enhanced under negative pulsing and reduced after positive pulsing. This hysteresis effect is similar to that observed with EOS capacitors, suggesting a field-dependent surface charge regulation mechanism at play. At high CG biases, nonvolatile charge Q(FG) tunneling into the FG occurs, which creates a larger field and tunes the pH response and the point of zero charge. This mechanism gives rise to surface programmability. In this paper we describe the operational principles, tunneling mechanism, and role of electrolyte composition under field modulation. The experimental findings are then modeled by a Poisson-Boltzmann formulation with surface pH regulation. We find that surface ionization constants play a dominant role in determining the pH tuning effect. In the following paper [K. Jayant et al., Phys. Rev. E 88, 012802 (2013)] we extend the dual-gate operation to molecular sensing and demonstrate the use of Q(FG) to achieve manipulation of surface-adsorbed DNA.

13.
Article in English | MEDLINE | ID: mdl-23944513

ABSTRACT

The chemoreceptive neuron metal-oxide-semiconductor transistor described in the preceding paper is further used to monitor the adsorption and interaction of DNA molecules and subsequently manipulate the adsorbed biomolecules with injected static charge. Adsorption of DNA molecules onto poly-L-lysine-coated sensing gates (SGs) modulates the floating gate (FG) potential ψ(O), which is reflected as a threshold voltage shift measured from the control gate (CG) V(th_CG). The asymmetric capacitive coupling between the CG and SG to the FG results in V(th_CG) amplification. The electric field in the SG oxide E(SG_ox) is fundamentally different when we drive the current readout with V(CG) and V(ref) (i.e., the potential applied to the CG and reference electrode, respectively). The V(CG)-driven readout induces a larger E(SG_ox), leading to a larger V(th_CG) shift when DNA is present. Simulation studies indicate that the counterion screening within the DNA membrane is responsible for this effect. The DNA manipulation mechanism is enabled by tunneling electrons (program) or holes (erase) onto FGs to produce repulsive or attractive forces. Programming leads to repulsion and eventual desorption of DNA, while erasing reestablishes adsorption. We further show that injected holes or electrons prior to DNA addition either aids or disrupts the immobilization process, which can be used for addressable sensor interfaces. To further substantiate DNA manipulation, we used impedance spectroscopy with a split ac-dc technique to reveal the net interface impedance before and after charge injection.


Subject(s)
DNA/analysis , Transistors, Electronic , Adsorption , DNA/chemistry , Dielectric Spectroscopy , Models, Theoretical
14.
Pediatrics ; 129(5): e1165-72, 2012 May.
Article in English | MEDLINE | ID: mdl-22508916

ABSTRACT

BACKGROUND AND OBJECTIVE: Both high and low lymphocyte counts at birth have been associated with adverse outcomes. However, the validity of defining a lymphocyte count as "abnormal" depends on having an accurate reference range. We established a reference range for neonatal lymphocyte counts by using multihospital data and used this to assess previously reported relationships between abnormal counts and early onset sepsis (EOS), intraventricular hemorrhage (IVH), retinopathy of prematurity (ROP), periventricular leukomalacia, and birth asphyxia. METHODS: We first created a data set that excluded counts from neonates with diagnoses previously associated with abnormal lymphocyte counts. Then the complete data (counts excluded plus included in the reference range) were used to test associations between abnormal counts and EOS, IVH, ROP, periventricular leukomalacia, and outcomes after birth asphyxia. RESULTS: Lymphocyte counts were retrieved from 40 487 neonates, 10 860 of which were excluded from the reference range. A count >95th percentile was associated with EOS (2.07; 95% confidence interval [CI]: 1.80-2.38) and IVH ≥grade 3 (2.93; 95% CI: 1.83-4.71). A count <5th percentile was associated with EOS (odds ratio:1.24; 95% CI: 1.04-1.48), IVH ≥grade 3 (3.23; 95% CI: 1.95-5.36), and ROP ≥stage 3 (4.80: 95% CI: 2.38-9.66). Among 120 meeting criteria for birth asphyxia, those with a low count and a high nucleated red cell count had higher mortality (37% vs 11%, P = .001), more transfusions (P = .000), and more neurology referrals (P < .01). CONCLUSIONS: A reference range for lymphocytes can identify neonates with abnormal counts, which can be useful because these neonates are at higher risk for certain adverse outcomes.


Subject(s)
Infant, Premature, Diseases/epidemiology , Infant, Premature, Diseases/etiology , Lymphocyte Count/statistics & numerical data , Neonatal Screening , Asphyxia Neonatorum/epidemiology , Asphyxia Neonatorum/etiology , Cerebral Ventricles , Cross-Sectional Studies , Gestational Age , Hospital Mortality , Humans , Infant, Newborn , Leukomalacia, Periventricular/epidemiology , Leukomalacia, Periventricular/etiology , Outcome Assessment, Health Care , Reference Values , Retinopathy of Prematurity/epidemiology , Retinopathy of Prematurity/etiology , Retrospective Studies , Risk Factors , Sepsis/epidemiology , Sepsis/etiology , Statistics as Topic , Utah
15.
Semin Thromb Hemost ; 37(3): 220-5, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21455856

ABSTRACT

Venous and arterial thromboembolism are both serious extraintestinal manifestations of inflammatory bowel disease (IBD). Acquired risk factors seem to play a more prominent role than congenital in promoting thrombotic events. Prevention of thromboembolism is thus mainly aimed at minimizing the acquired/reversible risk factors (e.g., inflammation, immobility, hospitalization, steroid therapy, central intravenous catheters, smoking, oral contraceptives, and deficiency of B vitamins and folate). The diagnosis of venous and arterial thromboembolism is extremely challenging and requires a high degree of vigilance. Deep vein thrombosis and pulmonary embolism may be clinically silent or manifest with only few specific symptoms. Thrombosis of the portal vein system may occur with nonspecific symptoms such as abdominal pain, nausea/vomiting, abdominal tenderness, ascites, and fever. The diagnosis of arterial thromboembolism may also be challenging, particularly when the splanchnic region is involved. Indeed, arterial thrombosis of the splanchnic region tends to be overlooked and misinterpreted as a clinical exacerbation of IBD. Early diagnosis plays a central role in optimizing the therapeutic intervention and reducing the risk of short-term and long-term thrombosis-associated complications. The decision regarding the duration of systemic anticoagulation must take into account the individual risk of intestinal bleeding.


Subject(s)
Inflammatory Bowel Diseases/complications , Thromboembolism/etiology , Adult , Factor V/genetics , Female , Humans , Pulmonary Embolism/etiology , Thromboembolism/drug therapy , Thromboembolism/epidemiology , Venous Thrombosis/drug therapy , Venous Thrombosis/etiology
16.
Fetal Pediatr Pathol ; 29(4): 185-98, 2010.
Article in English | MEDLINE | ID: mdl-20594142

ABSTRACT

Necrotizing enterocolitis (NEC) is a common gastrointestinal emergency of neonates. Population studies estimate the incidence of NEC at between 0.3 and 2.4 per 1000 live births in the United States, with a predominance of cases among preterm neonates born at the earliest gestational ages. The disease burden of NEC includes an overall disease-specific mortality rate of 15-20%, with yet higher rates in those of earliest gestations. The NEC burden also includes an increase in hospital costs approximating $100,000/case, as well as severe late sequellae including parenteral nutrition-associated liver disease and short bowel syndrome. Differentiating NEC from other forms of acquired neonatal intestinal disease is critical to assessing the success of NEC prevention strategies. Promising new prevention strategies are now being tested; one such is prophylactic heparin-binding epidermal growth factor-like growth factor (HB-EGF) administration. However, two prevention strategies have already been shown in meta-analyses to reduce the incidence of NEC, but we speculate that these are not being fully utilized. They are; 1) implementing a written set of feeding guidelines (also called standardized feeding regimens) for newborn intensive care unit (NICU) patients, and 2) implementing programs to increase the availability of human milk for patients at risk of developing NEC.


Subject(s)
Enterocolitis, Necrotizing/prevention & control , Infant, Premature, Diseases/prevention & control , Intercellular Signaling Peptides and Proteins/therapeutic use , Diet Therapy , Enterocolitis, Necrotizing/economics , Enterocolitis, Necrotizing/mortality , Guidelines as Topic , Heparin-binding EGF-like Growth Factor , Hospital Costs , Humans , Incidence , Infant Food , Infant, Newborn , Infant, Premature, Diseases/economics , Infant, Premature, Diseases/mortality , Infant, Very Low Birth Weight , Meta-Analysis as Topic , Milk, Human , Survival Rate
17.
Healthc Q ; 12 Spec No Patient: 116-22, 2009.
Article in English | MEDLINE | ID: mdl-19667788

ABSTRACT

By applying the Institute for Healthcare Improvement's framework for strategic change (will, ideas and execution), The Hospital for Sick Children, in Toronto, Ontario, developed processes to improve patient safety through the effective communication of critical test results. In response to an adverse patient event, near misses and accreditation requirements, a task force with representatives from the laboratories and clinical services was established to ensure the timely and reliable communication of critical test results for biochemistry, hematology, coagulation, therapeutic drug monitoring and microbiology. The task force critically assessed processes and best practices, identified practical alternatives, tested changes, codified new processes in a hospital-wide policy and procedure and carried out post-implementation outcome audits. Lessons learned in sustaining improvements included the following: there is value in identifying strategies from a larger system perspective; there exist merits to working collaboratively as an inter-professional team (i.e., laboratory and clinical leaders); there is value in learning from failure; higher-cost but "higher-leverage" approaches can be pivotal; and regular monitoring and vigilance of policy compliance are required.


Subject(s)
Academic Medical Centers , Clinical Laboratory Information Systems , Communication , Critical Care , Pediatrics , Efficiency, Organizational , Humans , Safety Management , Treatment Outcome
18.
Hum Mutat ; 30(8): E797-812, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19459153

ABSTRACT

Lynch syndrome is one of the most common autosomal dominantly inherited cancer syndromes. Mutations in MLH1, MSH2, MSH6, and PMS2 account for greater than 98% of reported mutations in Lynch syndrome families. It has been reported that large genomic deletions in MLH1 and MSH2 are a frequent cause of Lynch syndrome in certain populations. Using a multimodal approach, we have identified mutations in MLH1, MSH2, and MSH6 in French Canadian families fulfilling the Amsterdam criteria for Lynch syndrome and who displayed abnormal staining for at least one of the Lynch syndrome proteins. Mutations were identified in 28 of our 29 French Canadian probands (97%). A total of 18 distinct mutations (nine in MLH1, seven in MSH2, two in MSH6) were identified, of which six (33%) were genomic exon deletions. Another four (22%) resulted in exon deletions in cDNA alone. Three (17%) are novel mutations. Five of these 18 mutations were detected in more than one distinct family (four in MLH1, one in MSH2) and haplotype analysis suggests the possibility of founder effects. Fifteen of the 29 (52%) families carried one of these five putative founder mutations. These findings may simplify genetic testing for Lynch syndrome in French Canadians.


Subject(s)
Colorectal Neoplasms, Hereditary Nonpolyposis/genetics , Exons , Founder Effect , Base Sequence , Blotting, Southern , DNA Primers , DNA, Complementary , Haplotypes , Humans , Immunohistochemistry , Quebec
19.
Dis Colon Rectum ; 52(2): 336-42, 2009 Feb.
Article in English | MEDLINE | ID: mdl-19279432

ABSTRACT

Venous and arterial thromboembolism constitutes a significant cause of morbidity and mortality in patients with inflammatory bowel disease. The most common thrombotic manifestations are lower extremity deep vein thromboses with or without pulmonary embolism. Occasionally, thromboembolic events occur in the main abdominal vessels, such as the portal and superior mesenteric veins, vena cava and hepatic vein, aorta, splanchnic and iliac arteries, or in the limb arteries. The decision-making process for the treatment of these uncommon thromboembolic complications in inflammatory bowel disease may be very challenging for several reasons: 1) no standardized therapies are available; 2) the decision of starting anticoagulant therapy implies the potential risk of intestinal bleeding; 3) thromboembolic events may recur and be life-threatening if inadequately treated. The literature was searched by using MEDLINE, Embase, and the Cochrane library database. Studies published between 1970 and 2007 were reviewed. We discuss the medical and surgical therapeutic options that should be considered to optimize the outcome and reduce the risk of complications in abdominal thromboembolisms associated with inflammatory bowel disease.


Subject(s)
Inflammatory Bowel Diseases/complications , Thromboembolism/etiology , Aorta, Abdominal , Arteries , Budd-Chiari Syndrome/etiology , Extremities/blood supply , Hepatic Veins , Humans , Portal Vein , Venae Cavae
20.
J Surg Res ; 154(1): 38-44, 2009 Jun 01.
Article in English | MEDLINE | ID: mdl-19062046

ABSTRACT

BACKGROUND: The X-linked human androgen receptor gene (AR) contains an exonic polymorphic trinucleotide CAG. The length of this encoded CAG tract inversely affects AR transcriptional activity. Colorectal carcinoma is known to express the androgen receptor, but data on somatic CAG repeat lengths variations in malignant and normal epithelial cells are still sporadic. MATERIALS AND METHODS: Using laser capture microdissection (LCM), epithelial cells from colorectal carcinoma and normal-appearing mucosa were collected from the fresh tissue of eight consecutive male patients undergoing surgery (mean age, 70 y; range, 54-82). DNA isolated from each LCM sample underwent subsequent PCR and DNA sequencing to precisely determine AR CAG repeat lengths and the presence of microsatellite instability (MSI). RESULTS: Different AR CAG repeat lengths were observed in colorectal carcinoma (ranging from 0 to 36 CAG repeats), mainly in the form of multiple shorter repeat lengths. This genetic heterogeneity (somatic mosaicism) was also found in normal-appearing colorectal mucosa. Half of the carcinoma cases examined tended to have a higher number of AR CAG repeat lengths with a wider range of repeat size variation compared to normal mucosa. MSI carcinomas tended to have longer median AR CAG repeat lengths (n = 17) compared to microsatellite stable carcinomas (n = 14), although the difference was not significant (P = 0.31, Mann-Whitney test). CONCLUSIONS: Multiple unique somatic mutations of the AR CAG repeats occur in colorectal mucosa and in carcinoma, predominantly resulting in shorter alleles. Colorectal epithelial cells carrying AR alleles with shorter CAG repeat lengths may be more androgen-sensitive and therefore have a growth advantage.


Subject(s)
Carcinoma/genetics , Colorectal Neoplasms/genetics , Colorectal Neoplasms/surgery , Intestinal Mucosa/pathology , Mosaicism , Receptors, Androgen/genetics , Trinucleotide Repeats , Colorectal Neoplasms/pathology , Epithelial Cells/pathology , Exons , Humans , Male , Microsatellite Instability , Polymorphism, Genetic , Reference Values
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