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1.
J Perinatol ; 36(12): 1132-1137, 2016 12.
Article in English | MEDLINE | ID: mdl-27684422

ABSTRACT

OBJECTIVE: To evaluate the preparedness of pediatric residents entering accredited neonatal-perinatal medicine (NPM) fellowships in the United States. STUDY DESIGN: A multi-domain, validated survey was distributed to Program Directors (PDs) of US NPM fellowship programs. The 47-item survey explored 5 domains: professionalism, independent practice, psychomotor ability, clinical evaluation, and academia. A systematic, qualitative analysis on free-text comments was also performed. RESULTS: Sixty-one PDs completed the survey, for a response rate of 62% (61/98). For entering fellows, PDs assessed performance in professionalism positively, including 76% as communicating effectively with parents and 90% treating residents/house-staff with respect. In contrast, most PDs rated performance in psychomotor abilities negatively, including 59% and 79% as deficient in bag-and-mask ventilation and neonatal endotracheal intubation, respectively. Although 62% of PDs assessed entering fellows positively for genuine interest in academic projects, fewer than 10% responded positively that entering fellows understood research protocol design, basic statistics, or were capable of writing a cohesive manuscript well. Thematic clustering of qualitative data revealed deficits in psychomotor ability and academia/scholarship. CONCLUSIONS: On the basis of the perspective of front line educators, graduating pediatric residents are underprepared for subspecialty fellowship training in NPM. To provide the best preparation for pediatric graduates who pursue advanced training, changes to residency education to address deficiencies in these important competencies are warranted.


Subject(s)
Clinical Competence/standards , Fellowships and Scholarships/organization & administration , Internship and Residency/standards , Neonatology/education , Pediatrics/education , Biomedical Research/education , Curriculum , Humans , Surveys and Questionnaires , United States
2.
J Perinatol ; 36(8): 654-9, 2016 08.
Article in English | MEDLINE | ID: mdl-26963428

ABSTRACT

OBJECTIVE: To predict mortality or length of stay (LOS) >109 days (90th percentile) among infants with congenital diaphragmatic hernia (CDH). STUDY DESIGN: We conducted a retrospective analysis using the Children's Hospital Neonatal Database during 2010 to 2014. Infants born >34 weeks gestation with CDH admitted at 22 participating regional neonatal intensive care units were included; patients who were repaired or were at home before admission were excluded. The primary outcome was death before discharge or LOS >109 days. Factors associated with this outcome were used to develop a multivariable equation using 80% of the cohort. Validation was performed in the remaining 20% of infants. RESULTS: The median gestation and age at referral in this cohort (n=677) were 38 weeks and 6 h, respectively. The primary outcome occurred in 242 (35.7%) infants, and was distributed between mortality (n=180, 27%) and LOS >109 days (n=66, 10%). Regression analyses showed that small for gestational age (odds ratio (OR) 2.5, P=0.008), presence of major birth anomalies (OR 5.9, P<0.0001), 5- min Apgar score ⩽3 (OR 7.0, P=0.0002), gradient of acidosis at the time of referral (P<0.001), the receipt of extracorporeal support (OR 8.4, P<0.0001) and bloodstream infections (OR 2.2, P=0.004) were independently associated with death or LOS >109 days. This model performed well in the validation cohort (area under curve (AUC)=0.856, goodness-of-fit (GF) χ(2), P=0.16) and acted similarly even after omitting extracorporeal support (AUC=0.82, GF χ(2), P=0.05). CONCLUSIONS: Six variables predicted death or LOS ⩾109 days in this large, contemporary cohort with CDH. These results can assist in risk adjustment for comparative benchmarking and for counseling affected families.


Subject(s)
Hernias, Diaphragmatic, Congenital/mortality , Length of Stay/statistics & numerical data , Databases, Factual , Female , Gestational Age , Humans , Infant , Infant, Newborn , Intensive Care Units, Neonatal , Logistic Models , Male , Multivariate Analysis , Odds Ratio , Retrospective Studies , Risk Adjustment/methods , United States/epidemiology
3.
Gesundheitswesen ; 77(2): e20-5, 2015 Feb.
Article in German | MEDLINE | ID: mdl-25714194

ABSTRACT

OBJECTIVE: This study describes (i) the procedure of obtaining patients' consent for secondary data usage, (ii) the complexity of integrating data from multiple sources, and (iii) the correspondence among patients' self-reports, physician reports, routine data, hospital discharge diagnosis, and cause-of-death coding regarding stroke. METHODS: Data from the first follow-up (N=3 186) of the population-based Study of Health in Pomerania (SHIP) were used. These data were combined with secondary data from the Greifswald University Hospital, the association of statutory health insurance physicians Mecklenburg-Western Pomerania, physician reports, and death certificates. RESULTS: Consent for using health-related information from all data sources in question was obtained from more than 90% of the SHIP participants. Follow-up data from at least one source were available for 2 747 (86%) participants. For 92 participants information about the occurrence of stroke was found in at least one data source. In 59 cases the event appeared in only one data source, in 24 cases the event was found in 2 sources, and for 9 participants 3 data sources reported on the event. CONCLUSION: Participants of a population-based cohort are highly willing to give consent for using their health-related information from secondary data sources. Yet, data integration is challenging due to considerable differences in data type, structure and coverage.


Subject(s)
Hospitalization/statistics & numerical data , Informed Consent/statistics & numerical data , Medical Record Linkage/methods , Medical Records Systems, Computerized/statistics & numerical data , Stroke/mortality , Stroke/therapy , Data Accuracy , Feasibility Studies , Germany/epidemiology , Humans , Information Storage and Retrieval/statistics & numerical data , Meaningful Use/statistics & numerical data , National Health Programs/statistics & numerical data , Outcome Assessment, Health Care , Prevalence , Stroke/diagnosis , Survival Rate , Systems Integration , Treatment Outcome
4.
J Perinatol ; 35(4): 290-6, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25393081

ABSTRACT

OBJECTIVE: To characterize infants affected with perinatal hypoxic ischemic encephalopathy (HIE) who were referred to regional neonatal intensive care units (NICUs) and their related short-term outcomes. STUDY DESIGN: This is a descriptive study evaluating the data collected prospectively in the Children's Hospital Neonatal Database, comprised of 27 regional NICUs within their associated children's hospitals. A consecutive sample of 945 referred infants born ⩾36 weeks' gestation with perinatal HIE in the first 3 days of life over approximately 3 years (2010-July 2013) were included. Maternal and infant characteristics are described. Short-term outcomes were evaluated including medical comorbidities, mortality and status of survivors at discharge. RESULT: High relative frequencies of maternal predisposing conditions, cesarean and operative vaginal deliveries were observed. Low Apgar scores, profound metabolic acidosis, extensive resuscitation in the delivery room, clinical and electroencephalographic (EEG) seizures, abnormal EEG background and brain imaging directly correlated with the severity of HIE. Therapeutic hypothermia was provided to 85% of infants, 15% of whom were classified as having mild HIE. Electrographic seizures were observed in 26% of the infants. Rates of complications and morbidities were similar to those reported in prior clinical trials and overall mortality was 15%. CONCLUSION: Within this large contemporary cohort of newborns with perinatal HIE, the application of therapeutic hypothermia and associated neurodiagnostic studies appear to have expanded relative to reported clinical trials. Although seizure incidence and mortality were lower compared with those reported in the trials, it is unclear whether this represented improved outcomes or therapeutic drift with the treatment of milder disease.


Subject(s)
Hypothermia, Induced , Hypoxia-Ischemia, Brain/therapy , Seizures/therapy , Acidosis , Cohort Studies , Electroencephalography , Female , Focus Groups , Hospitals, Pediatric , Humans , Infant, Newborn , Intensive Care Units, Neonatal , Male , Resuscitation , Treatment Outcome
5.
J Perinatol ; 34(10): 736-40, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25144157

ABSTRACT

OBJECTIVE: To characterize the population and short-term outcomes in preterm infants with surgical necrotizing enterocolitis (NEC). STUDY DESIGN: Preterm infants with surgical NEC were identified from 27 hospitals over 3 years using the Children's Hospitals Neonatal Database; infants with gastroschisis, volvulus, major congenital heart disease or surgical NEC that resolved prior to referral were excluded. Patient characteristics and pre-discharge morbidities were stratified by gestational age (<28 vs 28(0/7) to 36(6/7) weeks' gestation). RESULT: Of the 753 eligible infants, 60% were born at <28 weeks' gestation. The median age at referral was 14 days; only 2 infants were inborn. Male gender (61%) was overrepresented, whereas antenatal steroid exposure was low (46%). Although only 11% had NEC totalis, hospital mortality (<28 weeks' gestation: 41%; 28(0/7) to 36(6/7) weeks' gestation: 32%, P=0.02), short bowel syndrome (SBS)/intestinal failure (IF) (20% vs 26%, P=0.06) and the composite of mortality or SBS/IF (50% vs 49%, P=0.7) were prevalent. Also, white matter injury (11.7% vs 6.6%, P=0.02) and grade 3 to 4 intraventricular hemorrhages (23% vs 2.7%, P<0.01) were commonly diagnosed. After referral, the median length of hospitalization was longer for survivors (106 days; interquartile range (IQR) 79, 152) relative to non-survivors (2 days; IQR 1,17; P<0.001). These survivors were prescribed parenteral nutrition infrequently after hospital discharge (<28 weeks': 5.2%; 28(0/7) to 36(6/7) weeks': 9.9%, P=0.048). CONCLUSION: After referral for surgical NEC, the short-term outcomes are grave, particularly for infants born <28 weeks' gestation. Although analyses to predict outcomes are urgently needed, these data suggest that affected infants are at a high risk for lengthy hospitalizations and adverse medical and neuro-developmental abnormalities.


Subject(s)
Enterocolitis, Necrotizing/mortality , Enterocolitis, Necrotizing/surgery , Hospital Mortality , Infant, Premature , Cause of Death , Cohort Studies , Databases, Factual , Digestive System Surgical Procedures/methods , Digestive System Surgical Procedures/mortality , Enterocolitis, Necrotizing/diagnosis , Female , Follow-Up Studies , Hospitals, Pediatric , Humans , Infant, Newborn , Intensive Care Units, Neonatal , Male , Referral and Consultation/statistics & numerical data , Retrospective Studies , Risk Assessment , Severity of Illness Index , Survival Rate , Time Factors , Treatment Outcome , United States
6.
J Perinatol ; 34(8): 582-6, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24603454

ABSTRACT

The Children's Hospitals Neonatal Consortium is a multicenter collaboration of leaders from 27 regional neonatal intensive care units (NICUs) who partnered with the Children's Hospital Association to develop the Children's Hospitals Neonatal Database (CHND), launched in 2010. The purpose of this report is to provide a first summary of the population of infants cared for in these NICUs, including representative diagnoses and short-term outcomes, as well as to characterize the participating NICUs and institutions. During the first 2 1/2 years of data collection, 40910 infants were eligible. Few were born inside these hospitals (2.8%) and the median gestational age at birth was 36 weeks. Surgical intervention (32%) was common; however, mortality (5.6%) was infrequent. Initial queries into diagnosis-specific inter-center variation in care practices and short-term outcomes, including length of stay, showed striking differences. The CHND provides a contemporary, national benchmark of short-term outcomes for infants with uncommon neonatal illnesses. These data will be valuable in counseling families and for conducting observational studies, clinical trials and collaborative quality improvement initiatives.


Subject(s)
Databases, Factual , Hospitals, Pediatric/statistics & numerical data , Infant, Newborn, Diseases/epidemiology , Intensive Care Units, Neonatal/statistics & numerical data , Outcome Assessment, Health Care/statistics & numerical data , Practice Patterns, Physicians'/statistics & numerical data , Humans , Infant, Newborn , Infant, Newborn, Diseases/diagnosis , Infant, Newborn, Diseases/therapy , Intensive Care Units, Neonatal/organization & administration , United States
7.
J Perinatol ; 34(7): 543-8, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24651732

ABSTRACT

OBJECTIVE: To estimate the risk of death or tracheostomy placement (D/T) in infants with severe bronchopulmonary dysplasia (sBPD) born < 32 weeks' gestation referred to regional neonatal intensive care units. STUDY DESIGN: We conducted a retrospective cohort study in infants born < 32 weeks' gestation with sBPD in 2010-2011, using the Children's Hospital Neonatal Database. sBPD was defined as the need for FiO2 ⩾ 0.3, nasal cannula support >2 l min(-1) or positive pressure at 36 weeks' post menstrual age. The primary outcome was D/T before discharge. Predictors associated with D/T in bivariable analyses (P < 0.2) were used to develop a multivariable logistic regression equation using 80% of the cohort. This equation was validated in the remaining 20% of infants. RESULT: Of 793 eligible patients, the mean gestational age was 26 weeks' and the median age at referral was 6.4 weeks. D/T occurred in 20% of infants. Multivariable analysis showed that later gestational age at birth, later age at referral along with pulmonary management as the primary reason for referral, mechanical ventilation at the time of referral, clinically diagnosed pulmonary hypertension, systemic corticosteroids after referral and occurrence of a bloodstream infection after referral were each associated with D/T. The model performed well with validation (area under curve 0.86, goodness-of-fit χ(2), P = 0.66). CONCLUSION: Seven clinical variables predicted D/T in this large, contemporary cohort with sBPD. These results can be used to inform clinicians who counsel families of affected infants and to assist in the design of future prospective trials.


Subject(s)
Bronchopulmonary Dysplasia/mortality , Tracheostomy/statistics & numerical data , Bronchopulmonary Dysplasia/surgery , Cohort Studies , Female , Gestational Age , Humans , Infant , Infant, Newborn , Infant, Premature , Intensive Care Units, Neonatal , Length of Stay/statistics & numerical data , Logistic Models , Male , Respiration, Artificial , Retrospective Studies , Risk Assessment
8.
J Perinatol ; 33(11): 877-81, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23828204

ABSTRACT

OBJECTIVE: To characterize the treatments and short-term outcomes in infants with severe bronchopulmonary dysplasia (sBPD) referred to regional neonatal intensive care units. STUDY DESIGN: Infants born <32 weeks' gestation with sBPD were identified using the Children's Hospital Neonatal Database. Descriptive outcomes are reported. RESULT: A total of 867 patients were eligible. On average, infants were born at 26 weeks' gestation and referred 43 days after birth. Infants frequently experienced lung injury (pneumonia: 24.1%; air leak: 9%) and received systemic corticosteroids (61%) and mechanical ventilation (median duration 37 days). Although 91% survived to discharge, the mean post-menstrual age was 47 weeks. Ongoing care such as supplemental oxygen (66%) and tracheostomy (5%) were frequently needed. CONCLUSION: Referred infants with sBPD sustain multiple insults to lung function and development. Because affected infants have no proven, safe or efficacious therapy and endure an exceptional burden of care even after referral, urgent work is required to observe and improve their outcomes.


Subject(s)
Bronchopulmonary Dysplasia/therapy , Infant, Premature , Adrenal Cortex Hormones/therapeutic use , Humans , Infant, Newborn , Intensive Care Units, Neonatal , Respiration, Artificial , Treatment Outcome
9.
Clin Pharmacol Ther ; 93(4): 360-5, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23443752

ABSTRACT

Serious safety issues relating to drugs are communicated to health-care professionals via Direct Health-Care Professional Communications (DHPCs). We explored which characteristics determined the impact of DHPCs issued in the Netherlands for ambulatory-care drugs (2001-2008). With multiple linear regression, we examined the impact on the relative change in new drug use post-DHPC of the following: time to DHPC, trend in use, degree of innovation, specialist drug, first/repeated DHPC, DHPC template, and type of safety issue. DHPCs have less impact on use of specialist drugs than nonspecialist drugs (P < 0.05). The DHPCs' impact increased after availability of a template emphasizing the main problem (P < 0.05), and for safety issues with a risk of death and/or disability (both P < 0.05) (adjusted R² = 0.392). Risk communication can be effective, specifically in case of well-structured information, and very serious safety issues. Effectiveness may improve by tailoring DHPCs and adding other communication channels, for example for drugs that are increasingly being used.


Subject(s)
Ambulatory Care/trends , Communication , Health Personnel/psychology , Medication Errors/trends , Practice Patterns, Physicians'/trends , Humans , Netherlands , Time Factors
10.
Clin Pharmacol Ther ; 91(5): 838-45, 2012 May.
Article in English | MEDLINE | ID: mdl-22472991

ABSTRACT

The effect of Direct Healthcare Professional Communications (DHPCs) informing health-care providers of serious drug safety issues has been questioned. The aim of this study was to evaluate the impact of DHPCs on drug use.Nationwide dispensing data for the period 2000­2008 for new users of 46 drugs with one or more DHPCs were assessed. Impact on short-term volume of use was evaluated with regression models, and the presence of long-term changes in use was evaluated with interrupted time series analyses incorporating preexisting trends. The short-term prescription level was lower post-DHPC in 28 (48.3%) of 58 cases. Twenty (34.5%) DHPCs resulted in long-term changes in use. A long-term mean reduction in use was observed in 26.7% of cases (95% confidence interval, −15.2 to −38.2%).Long-term changes in use were not significantly related to preexisting trends in use. Although short- and long-term decreases in use were observed after only half and a third of DHPCs, respectively, the decrease was substantial.


Subject(s)
Ambulatory Care , Drug and Narcotic Control , Drug-Related Side Effects and Adverse Reactions , Humans , Longitudinal Studies , Netherlands
11.
Biosens Bioelectron ; 25(6): 1389-94, 2010 Feb 15.
Article in English | MEDLINE | ID: mdl-19939660

ABSTRACT

Using electrochemical impedance spectroscopy (EIS) for biosensing applications typically requires repetitive experiments. To address this need, we have designed a multispecific electrochemical array with eight individually addressable 2mm-diameter gold working electrodes for rapid biosensing data accumulation by EIS in the presence of redox agent. The array allows to incorporate multiple negative controls in the course of a single binding experiment, as well as to perform parallel identical experiments to improve reliability of detection. The array is fit with attached electrochemical cell with Ag/AgCl mini reference electrode and can be used to process macro samples of 0.5-1 ml or micro samples of 5 microl in a drop-wise fashion. Eight individual EIS measurements are completed in 15 min. The reported array is disposable, economical and is easy to use. Examples of array use for label-free genetic sensing of 2.7 kb-long target Yersinia pestis DNA and for protein sensing of Ricin Toxin Chain A (RTA) are presented. We suggest the reported array design as a tool for researchers in the area of EIS sensing.


Subject(s)
Biosensing Techniques/instrumentation , Electrochemistry/instrumentation , Electrodes , Microarray Analysis/instrumentation , Plethysmography, Impedance/instrumentation , Equipment Design , Equipment Failure Analysis , Reproducibility of Results , Sensitivity and Specificity
12.
Anal Chem ; 81(10): 3944-9, 2009 May 15.
Article in English | MEDLINE | ID: mdl-19364089

ABSTRACT

Electrochemical impedance spectroscopy (EIS) measurement, performed in the presence of a redox agent, is a convenient method to measure molecular interactions of electrochemically inactive compounds taking place on the electrode surface. High sensitivity of the method, being highly advantageous, can be also associated with nonspecific impedance changes that could be easily mistaken for specific interactions. Therefore, it is necessary to be aware of all possible causes and perform parallel control experiments to rule them out. We present the results obtained during the early stages of aptamer-based sensor development, utilizing a model system of human alpha thrombin interacting with a thiolated DNA aptamer, immobilized on gold electrodes. EIS measurements took place in the presence of iron ferrocyanides. In addition to known method limitations, that is, inability to discriminate between specific and nonspecific binding (both causing impedance increase), we have found other factors leading to nonspecific impedance changes, such as: (i) initial electrode contamination; (ii) repetitive measurements; (iii) additional cyclic voltammetry (CV) or differential pulse voltammetry (DPV) measurements; and (iv) additional incubations in the buffer between measurements, which have never been discussed before. We suggest ways to overcome the method limitations.


Subject(s)
Aptamers, Nucleotide/chemistry , Biosensing Techniques/methods , Electrochemical Techniques/methods , Electrodes , Ferrocyanides/chemistry , Gold/chemistry , Humans , Oxidation-Reduction , Thrombin/analysis , Thrombin/chemistry
13.
Biotech Histochem ; 82(1): 17-22, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17510810

ABSTRACT

Fetuses develop in a marked hypoxic environment in utero. Premature infants often require high concentrations of oxygen to survive and develop in an environment that would be considered an oxygen stress for the fetus. Postnatal hyperoxia alters organ development, but there is minimal research regarding the role of hyperoxia in intestinal development. We attempted to determine whether postnatal hyperoxia exposure alters intestinal growth and function by using a reliable, objective and sensitive set of methods to study region-specific postnatal intestinal maturation. Rat pups born naturally were placed in continual exposure to room air (normoxia) or 85% oxygen (hyperoxia) immediately after birth. Pups were sacrificed at 1 and 2 weeks of age. Intestines were removed and fixed in formalin. Average mucosal, submucosal, and muscularis thicknesses were measured on hematoxylin and eosin stained sections. Immunohistochemistry was performed using antibodies against NOS II. The staining intensity was determined and quantified for site-specific regions of intestinal sections. No differences in mucosal thickness, submucosal thickness, or muscularis thickness were measured in the duodenum, jejunum or colon at any age. At two weeks of age, the thickness of the ileal mucosa was significantly greater in the group reared in 85% oxygen, and the group exposed to room air demonstrated significantly greater NOS II protein concentration than the hyperoxia group within the distal villus, proximal villus/crypts, submucosa, and muscularis in the distal small intestine.


Subject(s)
Hyperoxia , Ileum/growth & development , Animals , Animals, Newborn , Female , Hyperoxia/physiopathology , Ileum/anatomy & histology , Ileum/drug effects , Immunohistochemistry , Morphogenesis/drug effects , Oxygen/pharmacology , Pregnancy , Rats , Rats, Sprague-Dawley
14.
Am J Physiol Gastrointest Liver Physiol ; 280(1): G43-50, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11123196

ABSTRACT

We studied mesenteric arterial arcades from 3- and 35-day-old swine to determine the relationship between perfusate flow rate and release of nitric oxide (NO) into mesenteric effluent. Mesenteric arterial arcades were perfused under controlled-flow conditions with a peristaltic pump using warm oxygenated Krebs buffer. Basal rates of NO production were 43.6 +/- 4.2 vs. 12.1 +/- 2.5 nmol/min in 3- vs. 35-day-old mesentery during perfusion at in vivo flow rates (9 vs. 20 ml/min, respectively). Rate of NO production was directly related to flow rate over a wide range of flows (5-40 ml/min) in 3- but not 35-day-old mesentery. Both age groups demonstrated a brisk, albeit brief, increase in NO production in response to infusion of NO-dependent vasodilator substance P (10(-8) M/min). Tyrosine kinase inhibitor herbimycin A and L-arginine analog L-NMMA significantly attenuated flow-induced increase in NO production, and phosphatase inhibitor phenylarsine oxide increased magnitude of flow-induced increase in NO production in 3-day-olds. Removal of extracellular Ca(2+) and depletion of intracellular Ca(2+) stores (Ca(2+)-free Krebs with EGTA plus thapsigargin) had no effect on NO production in either group. Thus, basal rate of NO production is greater in mesenteric arterial arcades from 3- than from 35-day old swine, a direct relationship between flow rate and NO production rate is present in mesentery from 3- but not 35-day-olds, and phosphorylation events are necessary for this interaction to occur.


Subject(s)
Mesenteric Arteries/growth & development , Mesenteric Arteries/physiology , Nitric Oxide/metabolism , Splanchnic Circulation/physiology , Age Factors , Animals , Animals, Newborn , Benzoquinones , Blood Flow Velocity/physiology , Calcium/metabolism , Endothelium, Vascular/drug effects , Endothelium, Vascular/enzymology , Enzyme Inhibitors/pharmacology , Lactams, Macrocyclic , Nitric Oxide Synthase/metabolism , Nitric Oxide Synthase Type III , Phosphoric Monoester Hydrolases/antagonists & inhibitors , Phosphorylation , Protein-Tyrosine Kinases/antagonists & inhibitors , Quinones/pharmacology , Rifabutin/analogs & derivatives , Swine , Vasodilation/physiology , omega-N-Methylarginine/pharmacology
15.
Microcirculation ; 8(6): 377-87, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11781811

ABSTRACT

Significant changes occur in intestinal hemodynamics during the transition from fetal to newborn life and then again during the first postnatal month. Most importantly, basal vascular resistance substantially decreases following birth. It then decreases further between postnatal days 1 and 3, plateaus, and then begins a slow, progressive increase between postnatal days 12 and 30. The basal rate of intestinal blood flow mirrors the changes in vascular resistance in an inverse manner. The postnatal changes in vascular resistance appear to be mediated, in large part, by an increase in the constitutive and stimulated production of nitric oxide. Most importantly, the diameter of terminal mesenteric arteries (150-300 microm diameter) in newborn (i.e., 1 day old) swine is determined by three intrinsic vascular control systems: endothelial production of nitric oxide and endothelin, and the inherent myogenic response of vascular smooth muscle. In contrast, these vessels in older subjects (i.e., 35 days old) are primarily passive in nature and fail to demonstrate significant diameter change in response to blockade of endogenous nitric oxide production or endothelin receptors, or applied perturbations of pressure or flow rate. The circulatory physiology of the perinatal and newborn intestine is exceptional when compared to the adult condition inasmuch as several hemodynamic variables change quite dramatically between fetal and neonatal life and during the first postnatal month. The unique hemodynamic conditions that characterize the perinatal and newborn intestine appear to be part of the overall physiological transition that occurs as the fetus, once born, replaces the placenta with his gastrointestinal tract to obtain nutrition. The goal of this review is to describe the circulatory physiology of the perinatal and newborn intestine, with a particular emphasis on those portions of the intestinal microcirculation that have thus far been studied. First, however, it is important to discuss the age-dependent changes that occur within the intestinal circulation during perinatal and early newborn life.


Subject(s)
Intestines/blood supply , Age Factors , Animals , Animals, Newborn , Endothelin-1/physiology , Hemodynamics/drug effects , Humans , Infant, Newborn , Microcirculation/drug effects , Microcirculation/metabolism , Microcirculation/physiology , Nitric Oxide/physiology
16.
Am J Physiol ; 274(2): G290-8, 1998 02.
Article in English | MEDLINE | ID: mdl-9486182

ABSTRACT

The responses of buffer-perfused terminal mesenteric arteries from 3- and 35-day-old swine to manipulation of intravascular pressure and flow rate were determined. Under in vivo conditions, these vessels demonstrated age-dependent differences in resting diameter (182 vs. 301 microns in 3- vs. 35-day-old swine). A proximal-to-distal pressure gradient was present in vessels from both age groups (delta 13 vs. delta 16 mmHg in 3- vs. 35-day-old swine), suggesting their functional role as resistance vessels. Vessels were mounted within an in vitro perfusion apparatus that allowed independent regulation of inflow and outflow pressure. Vessels from both age groups demonstrated the development of active tone in response to an incremental rise in pressure, applied in the absence of flow. However, myogenic vasoconstriction was only observed in younger arterioles. Similarly, both groups demonstrated dilation in response to a flow stimulus generated in the absence of a net change in intravascular pressure, although the magnitude of this response was significantly greater in younger vessels (+27 vs. +7% in 3- vs. 35-day-old swine). The dilatory response to flow was eliminated by NG-monomethyl-L-arginine (10(-4)M) but restored by coadministration of L-arginine (10(-3)M). Myogenic vasoconstriction was overridden by flow-mediated dilation in terminal mesenteric arteries from 3- but not 35-day-old swine after concomitant application of pressure and flow stimuli. We conclude that the hemodynamic characteristics of terminal mesenteric arteries are age dependent in postnatal swine.


Subject(s)
Mesenteric Arteries/physiology , Animals , Animals, Newborn , Blood Pressure , Enzyme Inhibitors/pharmacology , Hemorheology , Intestines/blood supply , Intestines/growth & development , Mesenteric Arteries/anatomy & histology , Microcirculation , Nitric Oxide Synthase/antagonists & inhibitors , Swine , Vascular Resistance , Vasoconstriction , Vasodilation , omega-N-Methylarginine/pharmacology
17.
Pediatr Radiol ; 28(12): 923-7, 1998 Dec.
Article in English | MEDLINE | ID: mdl-9880632

ABSTRACT

BACKGROUND: A preterm infant was found to have total parenteral nutrition (TPN) ascites after infusion through a low umbilical vein catheter (UVC). Objective. To evaluate the clinical and imaging findings of neonates with TPN ascites after infusion through UVCs. MATERIALS AND METHODS: Eight patients with TPN ascites were identified over three years. Charts were abstracted for clinical data. Plain-film, ultrasound (US), and contrast studies through the UVCs were examined to determine UVC placement, presence of liver injury, and confirmation of intraperitoneal extravasation from the UVC. RESULTS: All eight patients with TPN ascites presented with hypotension and abdominal distension. All had UVCs overlying the liver on plain film. Catheters were in place a mean of 8.9 days prior to TPN extravasation. US in four patients showed hepatic parenchymal damage around the UVC tip. Contrast studies in six patients showed intraperitoneal spill. CONCLUSION: While low UVC placement may sometimes be clinically unavoidable, TPN administered through abnormally positioned UVCs is not without risk.


Subject(s)
Ascites/etiology , Catheters, Indwelling/adverse effects , Infant, Premature, Diseases/diagnosis , Liver/injuries , Parenteral Nutrition, Total/adverse effects , Umbilical Veins , Ascites/diagnostic imaging , Female , Humans , Infant, Newborn , Infant, Premature, Diseases/etiology , Liver/diagnostic imaging , Radiography , Ultrasonography
18.
Horm Res ; 7(4-5): 214-7, 1976.
Article in English | MEDLINE | ID: mdl-797645

ABSTRACT

NSILA-S was localized by immunofluorescent antibody staining in the exocrine part of the pancreas and the submaxillary salivary gland of the rat, where part of the cells give positive reactions. To a lesser degree it was demonstrated in the kidney, where some--probably the actually functioning--nephrons give positive staining reactions within their tubular cells. Radioimmunoassayable NSILA-S was found in extracts of the pancreas (120-550 ng/g), of the submaxillary salivary gland (220-330 ng/g) and of the kidney (45 ng/g), whereas liver (and some other organs) contain practically no NSILA-S.


Subject(s)
Nonsuppressible Insulin-Like Activity/analysis , Adrenal Glands/analysis , Animals , Fluorescent Antibody Technique , Gastric Mucosa/analysis , Intestinal Mucosa/analysis , Kidney/analysis , Male , Organ Specificity , Pancreas/analysis , Radioimmunoassay/methods , Rats , Submandibular Gland/analysis , Testis/analysis
19.
Horm Res ; 7(4-5): 201-13, 1976.
Article in English | MEDLINE | ID: mdl-1017791

ABSTRACT

By immunizing rabbits--tolerant against the bulk of normal human serum proteins--with highly purified non-suppressible insulin-like activity (NSILA-S), an antiserum was obtained which made possible the development of a double-antibody radioimmunoassay. Its sensitivity is about 30 pg NSILA-S per tube or 150 pg NSILA-S/ml. The specificity exceeds that of the bioassay used for comparison which is based in the stimulation by NSILA-S of 125IUDR incorporation into chicken fibroblasts in culture. The radioimmunoassay is sufficiently sensitive and specific to allow direct NSILA-S measurement in serum or plasma samples of humans and experimental animals. In human plasma samples NSILA-S levels, carrying between less than 0.15 and 25 ng/ml , were found to have an average of about 4 ng/ml. In rats higher levels were observed with a mean of 7.7 ng/ml in 4-week-old animals, increasing to about 60 ng/ml in 6-month-old rats. In fasting rats the NSILA-S plasma level is reduced. In acid-treated samples of plasma considerably higher NSILA-S amounts are found.


Subject(s)
Nonsuppressible Insulin-Like Activity/analysis , Animals , Biological Assay , Blood Proteins/metabolism , Chickens , Dogs , Evaluation Studies as Topic , Fibroblasts/metabolism , Goats , Humans , Idoxuridine/metabolism , Rabbits/immunology , Radioimmunoassay/methods , Rats
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