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Biomedical subjects

P Kapur

Publications and source records attributed to P Kapur.

At least 19 recordsLinked to original sources
PubMed2006

Surgical management of inflammatory bowel disease.

AIM: To evaluate the outcome and morbidity after major surgical interventions for inflammatory bowel disease (IBD). METHODS: Retrospective case note analysis of 227 children referred to a tertiary referral centre between 1994 and 2002 for treatment of IBD. RESULTS: 26 of 125 children with Crohn's disease (21%) required surgical management. 13 with disease proximal to the left colon underwent limited segmental resections and primary anastomosis, without significant morbidity. Primary surgery for 13 children with disease distal to the transverse colon included 6 subtotal-colectomies or panprocto-colectomies. All seven children undergoing conservative segmental resections (three with primary anastomosis, four with stoma formation), required further colonic resection or defunctioning stoma formation. All three children undergoing primary anastomosis developed a leak or fistula formation. 22 of 102 children with ulcerative colitis (22%) required surgery. Definitive procedures (n = 17) included J-pouch ileoanal anastomosis (n = 11), ileorectal anastomosis (n = 2), straight ileoanal anastomosis (n = 3), and proctectomy/ileostomy (n = 1). Five children await restorative surgery after subtotal colectomy. Median daily stool frequency after J-pouch surgery was 5 (range 3-15), and 10 of 11 children reported full daytime continence. All three children with straight ileoanal anastomosis had unacceptable stool frequency and remain diverted. CONCLUSION: The complication rate after resectional surgery for IBD was 57% for Crohn's disease, and 31% for ulcerative colitis. In children with Crohn's disease, limited resection with primary anastomosis is safe proximal to the left colon. Where surgery is indicated for disease distal to the transverse colon, subtotal or panproctocolectomy is indicated, and an anastomosis should be avoided. Children with ulcerative colitis had a good functional outcome after J-pouch reconstruction. However, the overall failure rate of attempted reconstructive surgery was 24%, largely owing to the poor results of straight ileoanal anastomosis.

Adolescent↗
PubMed1999

Tracheal ligation and mechanical ventilation do not improve the antioxidant enzyme status in the lamb model of congenital diaphragmatic hernia.

BACKGROUND/PURPOSE: The antioxidant enzyme (AOE) system is the primary intracellular defense system of the lung against oxygen toxicity. The authors recently demonstrated depressed levels of catalase, glutathione peroxidase, and superoxide dismutase in congenital diaphragmatic hernia (CDH) lambs compared with controls. The aim of this study was to determine whether tracheal ligation (TL) or mechanical ventilation (recently shown to stimulate growth and surfactant metabolism, respectively) could induce an elevation in AOE activity. METHODS: Four nonventilated lambs with surgically created CDH and TL and five CDH lambs ventilated for 4 hours were studied. Lung tissue was analyzed for AOE and the results compared with untreated CDH lambs. RESULTS: Both ventilation and TL failed to elevate AOE activity above that of untreated CDH lambs. CONCLUSIONS: The data provide further evidence that TL does not improve lung metabolism or maturation. Mechanical ventilation, which often involves high oxygen delivery, is a necessary and often beneficial therapeutic modality. In the CDH neonate compromised not only by low baseline levels of the AOE, but also by an inability to induce enzyme synthesis in response to hyperoxia, mechanical ventilation may, by causing lung injury, be contributing to the high morbidity and mortality rate associated with CDH.

Animals↗
PubMed1999

Lung physiological and metabolic changes in lambs with congenital diaphragmatic hernia after administration of prenatal maternal corticosteroids.

BACKGROUND/PURPOSE: Improved outcomes of preterm infants born to mothers treated prenatally with corticosteroids have been documented. The authors investigated the role of prenatal maternal corticosteroid therapy in congenital diaphragmatic hernia (CDH). METHODS: Five CDH lambs of ewes given 0.5 mg/kg betamethasone intravenously 24 hours before delivery (single-dose), four CDH lambs of ewes similarly dosed at 48 and 24 hours before delivery (double-dose), five untreated CDH lambs and five control lambs were studied. After 2 hours of ventilation, compliance, arterial oxygen (PO2) and carbon dioxide (pCO2) concentrations were recorded. Lavage protein and phospholipid levels were measured, and lung tissue was analyzed for antioxidant enzyme activity (AOE). RESULTS: No improvement in gas exchange was noted in either treatment group. Significant increases in compliance (P = .02) were noted in the double-dose steroid group, which were different from that of untreated CDH lambs or controls. Minimal changes in AOE activities were seen with steroid administration. CONCLUSIONS: Although the metabolic changes were not significant, the marked improvement in compliance seen in the double-dosed steroid group suggests a potential role for prenatal maternal corticosteroids in CDH. Further timing and dosage studies are warranted in this model.

Animals↗
PubMed1998

Contractile properties of intralobar pulmonary arteries and veins in the fetal lamb model of congenital diaphragmatic hernia.

BACKGROUND/PURPOSE: Pulmonary hypertension plays a significant role in the pathophysiology of congenital diaphragmatic hernia (CDH). Although there has been an intensive research effort directed at mediators that may cause pulmonary vasoconstriction, no single agent has been identified. The authors hypothesize that there may be an alteration in the cGMP-nitric oxide (NO) pathway of vasodilatation contributing to the pulmonary hypertension observed in CDH. The purpose of these studies is to begin to elucidate vasoactive properties of pulmonary vessels with particular attention to the cGMP-NO pathway of vasodilatation in fetal lambs with CDH. METHODS: Fourth-generation pulmonary arteries and pulmonary veins were dissected from both right and left lungs of eight, 139-day gestational fetuses with surgically created CDH. Vessels were studied with standard isolated tissue bath techniques. Experiments examined basal release of NO in endothelium-intact PVs and PAs of both right and left lungs by measuring the contractile force of vessels constricted with norepinephrine (NE) in the presence and absence of the nitric oxide synthase (NOS) inhibitor N(omega)-nitro-L-arginine (L-NA). Concentration-response curves to the vasodilating agents zaprinast and A23187 were also obtained in vessels contracted by NE. RESULTS: Left and right pulmonary artery responses to NE are enhanced over those of historic controls. Pretreatment of left pulmonary arteries with L-NA enhances the vasoconstrictor response to NE, whereas right PAs show no increased response. Relaxation responses to A23187 and zaprinast, in both left and right pulmonary arteries were not different from control lambs. Relaxation responses of both left and right pulmonary veins to A23187 and zaprinast are blunted compared with controls. This blunting is significantly more in left pulmonary veins than right. Further, right but not left pulmonary veins display enhanced vasoconstrictive response to NE after L-NA pretreatment. CONCLUSIONS: The NO-cGMP pathway of vasodilatation is abnormal in the near term, fetal lamb with CDH. These abnormalities were most apparent in pulmonary veins and may reflect abnormal NOS activity or content between left and right lungs of the fetal lamb with CDH. Pulmonary arteries from CDH lambs have basal and stimulated NO release equal to that of historic controls but appear to be hypersensitive to exogenous vasoconstrictors.

Animals↗
PubMed1998

Cervical ECMO cannula placement in infants and children: recommendations for assessment of adequate positioning and function.

BACKGROUND/PURPOSE: Cervical extracorporeal membrane oxygenation (ECMO) cannula position is often difficult to confirm by chest x-ray alone. Malposition requires a second surgery to rectify the problem. Reoperation places the patient at risk for infection, bleeding, or death. This study analyzes indications for cannula repositioning and suggests an alternative standard for intraoperative evaluation of catheter function as it relates to position. METHODS: The authors reviewed charts of 73 patients placed on arterio-venous ECMO through cervical vascular access. Reasons for repositioning of either cannula at the initial surgery or postoperatively were recorded. RESULTS: Of 73 patients, 18 (24.6%) required either arterial cannula or venous cannula repositioning. In 10 (55%) of these patients, cannula malposition was not detected by chest x-ray during the initial cannulation, and they therefore required a second cervical exploration for repositioning. CONCLUSIONS: Chest x-ray is not sensitive in demonstrating malpositioned cervical ECMO cannulae. Two-dimensional ECHO before wound closure, may be a superior, more cost effective means of assessing cannula placement and function than x-ray alone. Confirmation of cannula position and function, before wound closure, would reduce the risks involved with cervical reexploration.

Catheterization↗
PubMed1998

Pediatric hernias and hydroceles.

Hernias and hydroceles are common conditions of infancy and childhood, and inguinal hernia repair is one of the most frequently performed pediatric surgical operations. As a result of improved neonatal intensive care, more and more premature babies are being delivered, and consequently the incidence of neonatal inguinal hernia is increasing. The most important aspect of the management of neonatal inguinal hernias relate to its risk on incarceration, and emphasis is placed on this point. This article covers the embryology, incidence, clinical presentation, and treatment of groin hernias and hydroceles, as well as dealing with abdominal wall hernias other than umbilical hernias. This article places special emphasis on when a patient with a hernia or hydrocele should be referred to a pediatric surgeon.

Female↗
PubMed1997

Physiology and pathophysiology of lung development.

Over the past few years, there has been a considerable improvement in our understanding of the normal development of the fetal lung and its regulation. These advances have occurred mostly through increased knowledge of molecular biological mechanisms of growth and differentiation. These advances have also resulted in an improvement in our comprehension of the pathological basis of various pulmonary diseases. As a result of this new and improved knowledge, new and innovative therapeutic modalities are being introduced into clinical practice. The introduction of surfactant therapy into the clinical setting was one such milestone in neonatal respiratory management. Pulmonary surfactant is responsible for stabilising alveoli during normal respiration, thereby preventing atelectasis or alveolar flooding. Disease processes which result in an insufficiency in surfactant, such as respiratory distress syndrome (RDS) or congenital diaphragmatic hernia (CDH), generally carry a very high mortality rate. Exogenous surfactant administration reduces both the mortality and morbidity associated with RDS and its sequelae, and its efficacy in the treatment of CDH is now being evaluated clinically. Moreover, laboratory studies suggest that surfactant therapy may be used in combination with other treatments, such as tracheal occlusion to promote lung growth in CDH, in order to achieve a maximal effect in these complex, multifactorial lung diseases.

Journal Article↗
PubMed1993

Transforming growth factor alpha is trophic to pancreatic cancer in vivo.

Pancreatic cancer cell lines overexpress epidermal growth factor (EGF) receptors and also have the capacity to produce transforming growth factor alpha (TGF alpha), the alternate agonist of the EGF receptor. The purpose of this study was to determine if TGF alpha had a trophic effect on the growth of pancreatic cancer in vivo. Syrian golden hamsters were inoculated with 50,000 H2T hamster ductal pancreatic cancer cells. The hamsters were then randomised to three equal groups: the groups received either saline (control), EGF, or TGF alpha, each by intraperitoneal injection, three times a day. Treatment continued for seven weeks, and each week the hamsters were weighed and tumour areas were measured. The hamsters were then killed, and the tumours were excised, weighed, and extracted for assay of DNA content as a measure of cellularity. From week four onwards both EGF and TGF alpha significantly stimulated tumour growth. Although tumour weights were not significantly different, tumour DNA content had nearly doubled after exposure to both EGF and TGF alpha. It is concluded that like EGF, TGF alpha can stimulate pancreatic cancer growth in vivo, and this may in part explain the aggressive nature of these cancers in clinical practice.

Animals↗
PubMed1985

A multicenter study of the epidemiology of hepatitis B in anesthesia residents.

Practicing anesthesiologists are at high risk of hepatitis B infection, but the risk for anesthesia residents has not been assessed. Anesthesia residents at seven universities were surveyed to study the epidemiology of hepatitis B in these trainees. Hepatitis B virus markers in serum were measured and data from questionnaires were used to determine characteristics of anesthetic practice, effectiveness of strategies for hepatitis B virus infection control, and nonvocational hepatitis B risk factors. Of 267 participants, 12.7% (range of the seven centers, 8.7%-22.7%) had serum markers for hepatitis B virus. The seropositivity (17.8%) in anesthesia residents who had completed more than 12 months of nonanesthesia postgraduate clinical training, or who had practiced medicine in another specialty prior to anesthesia, was greater than in the other trainees (9.4%). Based on their risk and the ineffectiveness of current control measures, anesthesia residents who lack hepatitis B virus immunity should be vaccinated prior to or as early as possible in their training.

Anesthesiology↗
PubMed1982

Nonlinearity in pulmonary airway dynamics.

The paper describes an approach for determining nonlinearity in the pulmonary airway dynamic system, assuming a crude but linear model of the system. The linear electrical analogue representation of the dynamic system, found to be applicable only during the inspiratory phase of the respiration process, is considered as the basic model of the system. Control theory is used for nonlinearization of the dynamic process by considering the presence of an additional pressure source actuating the basic model and accounting for the system nonlinearity, which is found to be predominantly present during the expiratory phase. On analysis of the basic model, the form of the nonlinearizing signal is determined by examining the closeness between the model response and actual response of a typical patient. The use of this signal in a modified modelling of the process and in its computer simulation study is indicated.

Airway Resistance↗
PubMed1980

Spinal osseous angioma: gelfoam embolization.

An osseous spinal angioma presented with severe back pain and cord compression. Severe hemorrhage occurred during surgical decompression, but after preoperative embolisation of the feeding vessels a second operation was successful. Osseous spinal angioma seldom presents backache of a severe nature or medullary compression. In such case, surgical intervention may be attempted without pre-operative embolization of the feeding vessels.

Adult↗