Contralateral exploration and repair of occult inguinal hernias during laparoscopic inguinal hernia repair: systematic review and Markov decision process.

BACKGROUND: Contralateral clinically occult hernias are frequently noted at the time of laparoscopic unilateral inguinal hernia repair. There is no consensus on the role of contralateral exploration and repair. This systematic review assessed the safety and efficacy of operative repair of occult contralateral inguinal hernias found during unilateral repair. METHODS: PubMed, Embase, and the Cochrane Central Register of Controlled Trials were searched from inception to February 2020. Adults diagnosed with a unilateral inguinal hernia undergoing laparoscopic repair were included. The primary outcome was the incidence of occult contralateral hernias. Summative outcomes of operative and expectant management were reported along with development of a Markov decision process. RESULTS: Thirteen studies (1 randomized trial, 12 observational cohorts) with 5000 patients were included. The incidence of occult contralateral inguinal hernias was 14.6 (range 7.3-50.1) per cent. Among patients who underwent repair, 10.5 (4.3-17.0) per cent experienced a postoperative complication. Of patients managed expectantly, 29 per cent later required elective repair for symptoms. Mean follow-up was 36 (range 2-218) months. Using a Markov decision process, it was calculated that, for every 1000 patients undergoing unilateral inguinal hernia repair, contralateral exploration would identify 150 patients with an occult hernia. Repair would result in 15 patients developing a postoperative complication and 105 undergoing unnecessary repair. Alternatively, expectant management would result in 45 patients requiring subsequent repair. CONCLUSION: Contralateral repair is not warranted in patients with occult hernias diagnosed at the time of elective hernia repair. The evidence is largely based on observational studies at high risk of bias.

Importance of the physical exam: double-blind randomized controlled trial of radiologic interpretation of ventral hernias after selective clinical information.

PURPOSE: Increasingly, radiologic imaging is obtained as part of the pathway in diagnosing ventral hernias. Often, radiologists receive incomplete or incorrect clinical information from clinicians. OBJECTIVE: The aim of the study is to determine if clinical exam findings alter radiological interpretation of ventral hernias on CT. METHODS: This is a single-institution double-blind, randomized trial. All patients with a recent abdominal/pelvic CT scan seen in various surgical clinics were enrolled. A surgeon blinded to the CT scan findings performed a standardized physical examination and assessed for the presence of a ventral hernia. Seven independent radiologists blinded to the study design reviewed the scans. Each radiologist received one of three types of clinical exam data per CT: accurate (correct), inaccurate (purposely incorrect), or none. Allocation was random and stratified by the presence of clinical hernia. The primary outcome was the proportion of radiologic hernias detected, analyzed by chi square. RESULTS: 115 patients were enrolled for a total of 805 CT scan reads. The proportion of hernias detected differed by up to 25% depending on if accurate, no, or inaccurate clinical information was provided. Inaccurate clinical data in patients with no hernia on physical exam led to a significant difference in the radiologic hernia detection rate (54.3% versus 35.7%, p = 0.007). No clinical data in patients with a hernia on physical exam led to a lower radiologic hernia detection rate (75.0% versus 93.8%, p = 0.001). CONCLUSIONS: The presence and accuracy of clinical information provided to radiologists impacts the diagnosis of abdominal wall hernias in up to 25% of cases. Standardization of both clinical and radiologic examinations for hernias and their reporting are needed. TRIAL REGISTRATION: Clinicaltrials.gov, Number NCT03121131, https://clinicaltrials.gov/ct2/show/NCT03121131.

Primary skin closure after damage control laparotomy.

BACKGROUND: Damage control laparotomy (DCL) is used widely in the management of patients with traumatic injuries but carries significant morbidity. Surgical-site infection (SSI) also carries potential morbidity, increased costs and prolonged hospital stay. The aim of this study was to determine whether primary skin closure after DCL increases the risk of SSI. METHODS: This was a retrospective institutional review of injured patients undergoing DCL between 2004 and 2012. Outcomes of patients who had primary skin closure at the time of fascial closure were compared with those of patients whose skin wound was left open to heal by secondary intention. The association between skin closure and SSI was evaluated using propensity score-adjusted multivariable logistic regression. RESULTS: Of 510 patients who underwent DCL, primary fascial closure was achieved in 301. Among these, 111 (36.9 per cent) underwent primary skin closure and in 190 (63.1 per cent) the skin wound was left open. Fascial closure at the initial take-back surgery was associated with having skin closure (P < 0.001), and colonic injury was associated with leaving the skin open (P = 0.002). On multivariable analysis, primary skin closure was associated with an increased risk of abdominal SSI (P = 0.020), but not fascial dehiscence (P = 0.446). Of patients receiving skin closure, 85.6 per cent did not develop abdominal SSI and were spared the morbidity of managing an open wound at discharge. CONCLUSION: Primary skin closure after DCL is appropriate but may be associated with an increased risk of SSI.

Circular closure is associated with the lowest rate of surgical site infection following stoma reversal: a systematic review and multiple treatment meta-analysis.

AIM: Stoma reversal is frequently complicated by surgical site infection (SSI). To reduce SSI, several techniques for skin closure have been studied, with no agreement on which is best. The aim of this study was to identify the skin closure technique associated with the lowest rate of SSI following stoma reversal. METHOD: We systematically searched MEDLINE (PubMed and OvidSP), Scopus and clinical registries from 1 January 1980 to 24 March 2012, and included original reports on adult patients following stoma reversal. A network of treatments was created to map the comparisons between skin closure techniques, including primary closure, primary closure with a drain, secondary closure, delayed primary closure, loose primary closure and circular closure. Pairwise meta-analyses were performed for all available direct comparisons of closure types and heterogeneity was assessed. A multiple-treatments meta-analysis was conducted to estimate relative treatment effects between competing closure types (reported as an odds ratio with 95% credible interval, and a probability that each treatment is best). Several sensitivity analyses were performed. RESULTS: Fifteen studies were identified with a total of 2921 cases of stoma reversal. Overall, study quality was poor with observed low (one study), moderate (seven studies) and high (seven studies) risk of bias. Circular closure was associated with the lowest SSI risk (OR 0.12; 95% CI 0.02-0.40) and was the best of six skin closure techniques (probability of being best = 68.9%). Circular closure remained the best after sensitivity analyses. CONCLUSION: This study showed that circular closure is the best skin closure technique after stoma reversal in terms of SSI rate, but the quality of supporting evidence is limited, precluding definite conclusions.

Visualization of Rab3A dissociation during exocytosis: a study by total internal reflection microscopy.

Rab3A is a small G protein in the Rab3 subfamily, and is thought to act at late stage of exocytosis. However, the detailed mechanism of its action is not completely understood. To study the role of Rab3A in exocytosis, we used a total internal reflection fluorescence microscope to examine the fluorescence changes of EGFP-Rab3A-labeled and NPY-EGFP-labeled vesicles in PC12 cells upon stimulation. The fluorescence of EGFP-Rab3A-labeled and NPY-EGFP-labeled vesicles decreased while showing different patterns. The NPY-EGFP-labeled vesicles that exocytosed showed a transient fluorescence increase before NPY-EGFP fluorescence disappearance, which represents fusion and NPY release. This transient increase was diminished in cells that co-expressed the GDP-bound Rab3A mutant. The fluorescence of EGFP-Rab3A-labeled vesicles dispersed before disappearance, which represents the dissociation of Rab3A from the vesicles. The dispersion was not found in GTP-bound Rab3A mutant-labeled vesicles. Interestingly, EGFP-Rab3A F59S, a mutant unable to bind rabphilin, dissociates slower from the vesicles than wild type Rab3A and caused a slower release of NPY-EGFP. The results provide direct evidence to support the hypothesis that GTP hydrolysis and rabphilin are involved in Rab3A dissociation from the vesicles and the occurrence of exocytosis.

Hyperglycemia and morbidity and mortality in extremely low birth weight infants.

OBJECTIVE: The purpose of this study was to determine the association between hyperglycemia and mortality and late-onset infections (>72 h) in extremely low birth weight (ELBW) infants. STUDY DESIGN: Retrospective analysis of a prospective cohort study of 201 ELBW infants who survived greater than 3 days after birth. Mean morning glucose levels were categorized as normoglycemia (<120 mg/dl), mild-moderate hyperglycemia (120 to 179 mg/dl) and severe hyperglycemia (> or =180 mg/dl). Hyperglycemia was further divided into early (first 3 days of age) and persistent (first week of age). Logistic regression was performed to assess whether hyperglycemia was associated with either mortality or late-onset culture-proven infection, measured after 3 and 7 days of age. RESULTS: Adjusting for age, the odds ratio (OR) for either dying or developing a late infection was 5.07 (95% confidence interval (CI): 1.06 to 24.3) for infants with early severe hyperglycemia and 6.26 (95% CI: 0.73 to 54.0) for infants with persistent severe hyperglycemia. Adjusting for age, both severe early and persistent hyperglycemia were associated with increased mortality. Among survivors, there was no significant association between hyperglycemia and length of mechanical ventilation or length of hospital stay. Persistent severe hyperglycemia was associated with the development of Stage II/III necrotizing enterocolitis, after adjusting for age and male gender (OR: 9.49, 95% CI: 1.52 to 59.3). CONCLUSION: Severe hyperglycemia in the first few days after birth is associated with increased odds of death and sepsis in ELBW infants.

Tracking of secretory vesicles of PC12 cells by total internal reflection fluorescence microscopy.

Total internal reflection fluorescence microscopy is used to detect cellular events near the plasma membrane. Behaviours of secretory vesicles near the cell surface of living PC12 cells, a neuroendocrine cell line, are studied. The secretory vesicles are labelled by over-expression of enhanced green fluorescent protein-tagged Rab3A, one of the small G proteins involved in the fusion of secretory vesicles to plasma membrane in PC12 cells. Images acquired by a fast cooled charge-coupled device camera using conventional fluorescence microscopy and total internal reflection fluorescence microscopy are compared and analysed. Within the small evanescent range (< 200 nm), the movements of the secretory vesicles of PC12 cells before and after stimulation by high K+ are examined. The movements of one vesicle relative to another already docked on the membrane are detected. Total internal reflection fluorescence microscopy provides a novel optical method to trace and analyse the exocytotic events and vesicle specifically near a cell membrane without interference of signals from other parts of the cell.

Nitric oxide reduces blood pressure in the nucleus tractus solitarius: a real time electrochemical study.

Increasing evidence has demonstrated that nitric oxide (NO) is involved in central cardiovascular regulation. In this study, we directly measured extracellular NO levels, in real-time, in the nucleus tractus solitarius (NTS) of anesthetized cats using Nafion/Porphyrine/o-Phenylenediamine-coated NO sensors. We found that local application of L-arginine (L-Arg) induced NO overflow in NTS and hypotension. These responses were potentiated in the vagotomized animals. Pretreatment with NO synthase (NOS)/guanylate cyclase inhibitor methylene blue, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one or NO scavenger hemoglobin attenuated L-Arg-induced hypotension, suggesting that exogenous supplement of NO suppressed cardiac functions through the NOS/cyclic guanosine monophosphate mechanism. The role of endogenous NO was examined after local application of N(G)-nitro-L-arginine methyl ester (L-NAME). We found that L-NAME suppressed endogenous NO levels in NTS and elicited hypertension and tachycardia. Taken together, our data suggest that NO is tonically released in the NTS to inhibit blood pressure.

A technique for laparoscopic-assisted percutaneous drainage of infected pancreatic necrosis and pancreatic abscess.

BACKGROUND: Percutaneous drainage has been shown to be an acceptable method for treating both pancreatic abscesses and infected pancreatic necrosis. However, percutaneous techniques have certain shortcomings, including the time and labor required and failure of the catheters to adequately drain the particulate debris. Growing experience around the world indicates that there is a role for retroperitoneal laparoscopy as a means of facilitating the percutaneous drainage of infected pancreatic fluid collections and avoiding a laparotomy. Our technique is discussed in this paper. METHODS: Once infection is documented in a pancreatic fluid collection by fine-needle aspiration, one or more percutaneous drains are placed into the fluid collection(s). A computed tomography (CT) scan is repeated. If further drainage is indicated, retroperitoneoscopic debridement is performed. Using a combination of the percutaneous drain(s) and the post-drain CT scan, ports are placed and retroperitoneoscopic debridement of the necrosectum is performed under direct visualization. Prior to completion of the operation, a postoperative lavage system is created. RESULTS: Six patients with infected pancreatic necrosis have been treated with this technique. Prior to commencement of our laparoscopic protocol, all six patients would have required open necrosectomy. Four of the six patients were managed with retroperitoneoscopic debridement and catheter drainage alone. Complications included a colocutaneous fistula and a small flank hernia. There were no bleeding complications and no deaths. CONCLUSION: Although open necrosectomy remains the standard of care for the treatment of infected pancreatic necrosis and pancreatic abscess, there is growing evidence that laparoscopic retroperitoneal debridement is feasible.

Laparoscopic assisted percutaneous drainage of infected pancreatic necrosis.

BACKGROUND: Percutaneous drainage of infected pancreatic fluid collections is often unsuccessful. Alternatively, open necrosectomy techniques are very morbid. We hypothesized that in selected cases, laparoscopic techniques could be used to facilitate percutaneous drainage of the residual particulate necrosectum and avoid a laparotomy. We report our experience with laparoscopic assisted retroperitoneal debridement as an adjunct to percutaneous drainage for patients with infected pancreatic necrosis. METHODS: Case studies were reviewed retrospectively. We analyzed the course of six patients undergoing laparoscopic assisted debridement of infected pancreatic necrosis after failure of percutaneous drainage. With the drains and computed tomography (CT) scan used as a guide, laparoscopic debridement of the necrosectum was performed. RESULTS: Between November 1995 and December 1999, six patients were treated with this method. In four patients, laparoscopic assisted percutaneous drainage was successful. Two patients required open laparotomy. Complications included a self-limited enterocutaneous fistula and a small flank hernia. No deaths occurred. CONCLUSIONS: This early, limited experience has demonstrated the feasibility of laparoscopic assisted percutaneous drainage for infected pancreatic necrosis. With this technique, two-thirds of our patients avoided the morbidity of a laparotomy.

Proteomic analysis of proteins in PC12 cells before and after treatment with nerve growth factor: increased levels of a 43-kDa chromogranin B-derived fragment during neuronal differentiation.

Proteomic analysis is an important approach to characterizing the proteome and studying protein function in the post-genomic era. It is also a powerful screening method for detecting unexpected alterations in protein expression that may be missed by conventional biochemical techniques. The aim of this study was to perform a preliminary proteomic analysis of PC12 cells in order to investigate the effect of nerve growth factor (NGF) on protein expression in PC12 cells during neurite outgrowth. PC12 cell proteins were separated by two-dimensional electrophoresis (2DE) and visualized by silver staining, then certain proteins were identified by N-terminal amino acid microsequencing and a homology search of a protein sequence database. Over 400 proteins were detected, 10% of which showed a significant (greater than 30%) increase or decrease in expression during NGF-induced neuronal differentiation. Seven proteins in the 2DE map were identified; the levels of five of these were unaffected by NGF treatment, whereas the levels of the other two, beta-tubulin and a novel 43-kDa chromogranin B-derived fragment, were significantly increased by more than 30 and 200%, respectively. Our results suggest that chromogranin B processing is enhanced in PC12 cells during NGF-induced neuronal differentiation. In addition, since this increase in the levels of the chromogranin B-derived fragment was specifically blocked by PD98059, we suggest that the increased processing can be ascribed to activation of the MAP kinase pathway, and that the 43-kDa chromogranin B-derived fragment can serve as a new marker of neuronal differentiation for proteomic studies.

Relative contribution of the Na(+)/Ca(2+) exchanger, mitochondria and endoplasmic reticulum in the regulation of cytosolic Ca(2+) and catecholamine secretion of bovine adrenal chromaffin cells.

The relative importance of mitochondria, the Na(+)/Ca(2+) exchanger (NCX) and the endoplasmic reticulum (ER) in the regulation of the cytosolic Ca(2+) concentration ([Ca(2+)](i)) were examined in bovine chromaffin cells using fura-2 for average [Ca(2+)](i) and amperometry for secretory activity, which reflects the local Ca(2+) concentration near the exocytotic sites. Chromaffin cells were stimulated by a high concentration of K(+) when the three Ca(2+) removal mechanisms were individually or simultaneously inhibited. When the mitochondrial Ca(2+) uptake was inhibited, the [Ca(2+)](i) decayed at a significantly slower rate and the secretory activity was higher than the control cells. The NCX appears to function only in the initial phase of [Ca(2+)](i) decay and when the ER Ca(2+) pump is blocked. Similarly, the ER had a significant effect on the [Ca(2+)](i) decay and on the secretion only when the NCX was blocked. Inhibition of all three mechanisms leads to a substantial delay in [Ca(2+)](i) recovery and an increase in the secretion. The results suggest that the three mechanisms work together in the regulation of the Ca(2+) near the Ca(2+) channels and exocytotic sites and therefore modulate the secretory activity. When Ca(2+) diffuses away from the exocytotic sites, the mitochondrial Ca(2+) uptake becomes the dominant mechanism.

Modulation of dopamine transporter activity by nicotinic acetylcholine receptors and membrane depolarization in rat pheochromocytoma PC12 cells.

To elucidate the regulation of the rat dopamine transporter (rDAT), we established several PC12 variants overexpressing the rDAT. Treating these cells with a nicotinic agonist (1,1-dimethyl-4-phenylpiperazinium iodide, 30 microM) depolarized the plasma membrane potential from -31 +/- 2 to 43 +/- 5 mV and inhibited rDAT activity significantly in a calcium- and protein kinase C-independent manner. Membrane depolarization by a high external K+ concentration or two K+ channel blockers (tetraethylammonium hydroxide and BaCl2) also resulted in a marked inhibition of rDAT activity. Such inhibition of dopamine uptake is due to a reduction in Vmax, with no marked effect on the Km for dopamine. The potency of cocaine in inhibiting dopamine uptake was not significantly altered, whereas that of amphetamine was slightly enhanced by membrane depolarization. Removing extracellular Ca2+ or blocking the voltage-sensitive L-type calcium channels using nifedipine did not exert any significant effect on the inhibition of rDAT activity by depolarization. These data confirm that calcium influx on depolarization is not required for inhibition of the rDAT. Collectively, our data suggest that rDAT activity can be altered by a neurotransmitter that modulates the membrane potential, thus suggesting an exquisite mechanism for the fine-tuning of dopamine levels in the synapse.

Molecular study of the Na+/Ca2+ exchanger in bovine adrenal chromaffin cells.

To identify the Na+/Ca2+ exchanger expressed in bovine chromaffin cells, the ncx gene was cloned from a bovine chromaffin cell cDNA library. Five partial clones were obtained and their nucleotide sequences showed that there were at least three isoforms containing different intracellular loops. The 3'-untranslated region was the same in all the clones. To examine the Na+/Ca2+ exchange activity of the clones, full-length ncx1 genes were constructed by replacing the corresponding region of bovine cardiac ncx1 clone p17 with the different regions from two bovine chromaffin cell clones; these were designated p17c and p17h. p17h, but not p17c, showed Na+/Ca2+ exchange activity when expressed in Chinese hamster ovary cells and Xenopus oocytes. The expressed exchange activity of p17 was inhibited by 8-bromoadenosine 3':5'-cyclic monophosphate (8-Br-cAMP) but was not affected by PMA. However, the activity of p17h was inhibited by PMA but enhanced by 8-Br-cAMP. The agents that changed the activity of protein kinase C and cAMP-dependent protein kinase modulated the endogenous Na+/Ca2+ exchange current of chromaffin cells in a manner similar to that of p17h. Our results suggest that the p17h clone is the major isoform of the exchanger in chromaffin cells and is similar to the major ncx1 isoform in kidney. The exchange activity could be regulated by phosphorylation, and the variable region in the intracellular loop is important for the different effects of phosphorylation on the different isoforms.

Involvement of Ca2+ signalling in the vasoactive intestinal peptide and 8-Br-cAMP induction of c-fos mRNA expression.

Vasoactive intestinal peptide (VIP) is known to signal via Gs mediated pathways. VIP stimulated c-fos mRNA expression in a clonal GH3 pituitary tumour cell line, GH3Ca, whereas 8-Br-cAMP only moderately induced c-fos expression. The VIP-induced c-fos expression was inhibited in the presence of EGTA, or the L-type Ca2+ channel blockers verapamil and nifedipine. Measurement of intracellular Ca2+ concentration ([Ca2+]i) by Fura-2 indicates that VIP gradually elevates [Ca2+]i, with the maximum level attained at 4 min following hormone addition. No [Ca2+]i increase could be detected in Ca2+ free buffer or in buffer containing nifedipine or verapamil, which suggests that VIP induced Ca2+ entry from L-type Ca2+ channels. 8-Br-cAMP rapidly increased [Ca2+]i, with a maximum concentration attained within 1 min of its addition and the elevated level maintained for 15 min. In the absence of external Ca2+ or in the presence of verapamil or nifedipine, the sustained Ca2+ increase was abolished whereas the transient Ca2+ peak was unaffected. Depletion of the internal calcium pools by thapsigargin (1 microM, 30 min), on the other hand, blocked the rapid transient [Ca2+], rise, suggesting the biphasic [Ca2+]i elicited by 8-Br-cAMP was due to mobilization from internal Ca2+ pool followed by extracellular flow. Interestingly, pretreatment with thapsigargin greatly potentiated the 8-Br-cAMP-stimulated c-fos expression. Pretreatment of cells with cholera toxin (1 microg/ml, 9 h) to deplete Gs proteins abolished VIP stimulated-[Ca2+] elevation, while it had little effect on the 8-Br-cAMP induced [Ca2+]i rise. Our results show that VIP increased Ca2+ influx from L-type channel through a Gs-mediated mechanism and this Ca2+ entry across the plasma membrane plays a major role in the hormone induced c-fos mRNA expression.

Catecholamine secretion from bovine adrenal chromaffin cells: the role of the Na+/Ca2+ exchanger and the intracellular Ca2+ pool.

The role of the Na+/Ca2+ exchanger and intracellular nonmitochondrial Ca2+ pool in the regulation of cytosolic free calcium concentration ([Ca2+]i) during catecholamine secretion was investigated. Catecholamine secretion and [Ca2+]i were simultaneously monitored in a single chromaffin cell. After high-K+ stimulation, control cells and cells in which the Na+/Ca2+ exchange activity was inhibited showed similar rates of [Ca2+]i elevation. However, the recovery of [Ca2+]i to resting levels was slower in the inhibited cells. Inhibition of the exchanger increased the total catecholamine secretion by prolonging the secretion. Inhibition of the Ca2+ pump of the intracellular Ca2+ pool with thapsigargin caused a significant delay in the recovery of [Ca2+]i and greatly enhanced the secretory events. These data suggest that both the Na+/Ca2+ exchanger and the thapsigargin-sensitive Ca2+ pool are important in the regulation of [Ca2+]i and, by modulating the time course of secretion, are important in determining the extent of secretion.

Characterization of Rab3A, Rab3B and Rab3C: different biochemical properties and intracellular localization in bovine chromaffin cells.

In this study we examined the biochemical properties and subcellular localization of Rab3A, Rab3B and Rab3C in bovine adrenal chromaffin cells. The Kd for guanosine 5'-[gamma-thio]triphosphate (GTP[S]) of the three Rab3 proteins was 15, 2700 and 204 nM for Rab3A, Rab3B and Rab3C respectively. The intrinsic GTPase activity of the three Rab3 proteins seemed similar and was increased approx. 3-fold by bovine chromaffin cell lysate. Truncation of the C-terminal 31 amino acid residues decreased the binding affinity for GTP[S] of the three Rab3 proteins. When the C-terminus of Rab3C was replaced with that of Rab3A, the binding affinity of Rab3C for GTP[S] was decreased, but the replacement did not affect the affinity of Rab3B for GTP[S]. Immunostaining experiments showed that Rab3A, Rab3B and Rab3C are localized separately within chromaffin cells. Anti-Rab3A and anti-Rab3C antibodies stained vesicle-like structures, whereas anti-Rab3B antibody distinctly stained the plasma membrane. In summary, bovine chromaffin cells express the three Rab3 proteins but the subcellular localization and biochemical properties of the three Rab3 proteins are distinct.