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Biomedical subjects

A Bhan

Publications and source records attributed to A Bhan.

At least 55 records · Page 3Linked to original sources
PubMed1998

Prostaglandin E1 in infants with congenital heart disease: Indian experience.

BACKGROUND: E-type prostaglandins (PGE1) can effectively maintain the patency of the ductus arteriosus in neonates. Its use, therefore and be life saving in infants born with ductus dependent congenital heart disease. Although PGE1 is available for over two decade in western world, it has been introduced in India only since April, 1995. OBJECTIVE: To assess the efficacy of PGE1 at our center. SETTING: Hospital based. METHOD: 65 infants with ductus dependent congenital heart disease were included. Age at time of starting PGE1 infusion ranged from 18 hours to 39 days. Forty two of these were more than a week of age, 19 were more than 14 days, and two were above one month. PGE1 was started in an initial dose of 0.05 microgram/kg/min, decreased to 0.005-0.01 microgram/kg/min for maintenance. The indications for use of PGE1 were to increase pulmonary blood flow in 33 cases with pulmonary atresia, tricuspid atresia or critical pulmonic stenosis (Group I); to increase systemic blood flow in 15 cases with coarctation of aorta, hypoplastic left heart and interruption of aortic arch (Group II); to improve mixing in 13 cases of transposition of great arteries (Group III) and for improving the left ventricular volumes by keeping the duct open in 4 cases of transposition of great arteries with intact ventricular septum (Group IV). The efficacy of the drug was assessed by a rise on PaO2 and SaO2% determined for Group I & III, and by appearance of lower limbs pulses in Group II. Left ventricular volumes were serially measured by echocardiography in Group IV cases. RESULTS: The drug was successful in 62 of the 65 cases. There were two failures. One was a 39 days old baby with Ebstein's anomaly of tricuspid valve and pulmonary atresia and other was an eight days old baby with coarctation of aorta and renal failure. In addition, PGE1 could not be continued in another baby due to development of a linear skin rash locally. Side effects included apnea in 5 (9%) of 56 spontaneously breathing patients. Necrotizing enterocolitis, hyperpyrexia and jitteriness was sent in one case each. Six patients died. Two were related to PGE1, one due to failure, another due to its side effects. Definitive procedure were performed in 51 cases electively. PGE1 was used upto 13 days with sustained benefit. CONCLUSIONS: PGE1 is an effective drug for keeping the ductus open in infants with ductus dependent congenital heart disease. It can be used for neonates beyond the first week of life with efficacy. Apnea is a major side effect and close monitoring is essential.

Age Factors↗
PubMed1998

Coronary artery bypass grafting without cardiopulmonary bypass.

Coronary artery bypass surgery on a beating heart is now an accepted modality to treat selected patients of ischaemic heart disease. From June '92 through Sep '97, 162 patients underwent this procedure. There was no mortality and none of the patients had any respiratory or neurological morbidity, though 24% of the patients form a high risk group for conventional coronary bypass surgery. It is definitely cost effective in comparison to any other modalities for treatment of ischaemic heart disease. We conclude that continous use of this technique is justified and all cardiac surgeons should have exposure to this procedure.

Adult↗
PubMed1997

Severe hypoxic biventricular dysfunction in tetralogy of Fallot: is Blalock shunt the answer?

In a 4-year-old boy with tetralogy of Fallot, a right modified Blalock-Taussig anastomosis was created because of severe myocardial dysfunction and repeated hypercyanotic spells. Post-operatively, systemic oxygen saturation improved and also myocardial function. It is postulated that hypoxia was responsible for myocardial dysfunction previously, and its elimination has resulted in markedly improved cardiac performance.

Child, Preschool↗
PubMed1997

Aortic atherosclerosis and perioperative stroke in patients undergoing coronary artery bypass: role of intra-operative transesophageal echocardiography.

Intra-operative transesophageal echocardiography was performed in 126 patients undergoing coronary artery bypass grafting. Significant protruding atheromas (grade IV and V; Katz et al., 1992) were present in 12 patients (9.5%). Protruding atheromas had significantly higher incidence in patients above 60 years in age. Preoperative assessment with chest roentgenography and angiography, as well as intra-operative assessment by surgical palpation proved to be insensitive in detecting aortic atheromas. Out of four patients with grade V atheromas, two (50%) developed right hemiplegia postoperatively. For the rest, patients with grade V atheromas and eight patients with grade IV atheromas, surgical technique was modified and that helped in preventing occurrence of perioperative stroke.

Adult↗
PubMed1997

2',5'-linked oligo-3'-deoxyribonucleoside phosphorothioate chimeras: thermal stability and antisense inhibition of gene expression.

2',5'-Linked oligo-3'-deoxyribonucleotides bind selectively to complementary RNA but not to DNA. These oligonucleotides (ODNs) do not recognize double-stranded DNA by Hoogsteen triplex formation and the complexes formed by these ODNs with RNA are not substrates for Escherichia coli RNase H. Substitution of the 2',5'-phosphodiester backbone by phosphorothioate linkages gives 2',5'-linked oligo-3'-deoxynucleoside phosphorothioate ODNs that exhibit significantly less non-specific binding to cellular proteins or thrombin. Incorporation of a stretch of seven contiguous 3',5'-linked oligo-2'-deoxynucleoside phosphorothioate linkages in the center of 2',5'-linked ODNs (as a putative RNase H recognition site) afford chimeric antisense ODNs that retain the ability to inhibit steroid 5alpha-reductase (5alphaR) expression in cell culture.

Base Composition↗
PubMed1997

Expression of the neonatal Fc receptor, FcRn, on human intestinal epithelial cells.

Maternal IgG is transferred to the suckling mouse and rat through a major histocompatibility complex (MHC) class I-related Fc receptor (FcRn) on the brush border of the proximal small intestine. We have previously described a site on the epithelial surface of the human fetal intestine with IgG binding characteristics similar to FcRn. We report here the identification by reverse transcriptase polymerase chain reaction amplification and sequencing of the human orthologue of rat and mouse FcRn in tissue obtained from human fetal and adult intestine. FcRn protein was detected in adult human intestine by western blot. Immunohistochemical studies of sections of human intestine show that the FcRn is localized mostly to the epithelial cells, where it is in the apical region. These data suggest that the binding of IgG previously seen in the fetal intestine is due to the presence of FcRn. Potential roles for this MHC class I-like Fc receptor in the human intestine include the transfer of passive immunity, induction of oral tolerance, and immunosurveillance.

Adult↗
PubMed1997

Enterocytes are the primary source of the chemokine ENA-78 in normal colon and ulcerative colitis.

Epithelial cell-derived neutrophil-activating protein-78 (ENA-78) is a neutrophil-directed C-X-C chemokine. We report that Caco-2 and T84 human intestinal epithelial cells produce ENA-78 after stimulation by interleukin (IL)-1 beta or tumor necrosis factor-alpha. Caco-2 cells show increased IL-8 production at 4-12 h and increased ENA-78 production at 8-24 h after cytokine stimulation. Immunohistochemical studies in normal human colon and in ulcerative colitis demonstrate ENA-78 immunoreactivity principally associated with crypt epithelial cells. Furthermore, human colonic tissues from patients with ulcerative colitis show elevated levels of ENA-78 mRNA (24-fold increase, P < 0.01) and protein (4-fold increase, P < 0.05) compared with normal controls. Thus ENA-78 is produced in normal colon and in ulcerative colitis and is predominantly of enterocyte origin. The kinetics of ENA-78 induction in human colon epithelial cell lines are delayed and prolonged compared with IL-8. We propose that ENA-78 and IL-8 serve complementary and sequential roles in neutrophil recruitment in ulcerative colitis. ENA-78 as an enterocyte-derived, neutrophil-activating chemokine may be especially important in neutrophil recruitment from the lamina propria into the epithelial layer.

Cell Line↗
PubMed1996

Surgical experience with total correction of tetralogy of Fallot in infancy.

Fifty two patients less than one year old with tetralogy of Fallot underwent primary repair between January 1991 and December 1994. Age range was three to twelve months (mean 10.09 +/- 2.01 months) and body weight ranged from 4.5 to 9 kg (mean 8.38 +/- 2.79 kg). Transatrial-transpulmonary repair was performed in 36 patients and the classical transventricular approach was used in 16 patients. Six patients underwent emergency surgery for severe cyanosis and spells. Five patients had left pulmonary artery plasty for pulmonary artery bifurcation stenosis and two out of the five patients who had anomalous coronary arteries needed a right ventricle to pulmonary artery conduit. Mean post repair peak right ventricular/systemic pressure ratio was 0.74 +/- 0.18 in the transventricular group and 0.71 +/- 0.26 in the transatrial-transpulmonary group. There were three hospital deaths. Follow-up ranged from 3 to 46 months (mean 21.18 months). Forty patients underwent echocardiography and twenty patients underwent cardiac catheterisation six to eighteen months after surgery. Mean right ventricular outflow tract gradient on echocardiography was 20.35 +/- 10.12 and, at cardiac catheterisation, 17.51 +/- 13.49 mmHg with mean post repair peak right ventricle/left ventricle pressure ratio of 0.44 +/- 0.11. These were significantly less than the values obtained in the operating room. Only one patient had residual ventricular septal defect with left to right shunt of 1.6:1 at cardiac recatheterisation. There was one late death after reoperation for residual obstruction. Encouraging results with primary repair of tetralogy of Fallot in infancy prompt us to continue this policy in suitable cases.

Body Weight↗
PubMed1995

Serial echocardiography for decision making in rapid two-stage arterial switch operation.

BACKGROUND: Rapid two-stage arterial switch operation is advocated in infants with simple transposition presenting late. Accurate assessment of left ventricular preparation is crucial to successful outcome. The role of echocardiography alone in surgical decision making remains unclear. METHODS: Seventeen patients with simple transposition (mean age, 4 months) underwent pulmonary artery banding and modified Blalock-Taussig shunt (first stage) to prepare the left ventricle for the arterial switch operation (second stage). Serial echocardiography was performed in the interval phase to assess left ventricular growth. Sixteen patients underwent arterial switch operation after a mean interval of 10.4 +/- 4 days, with 14 successful conversions. There was one mortality (5.9%) and two conversions to a Senning repair. RESULTS: In all patients a mean increase in left ventricular mass (40.8 +/- 17.8 g/m2 to 81.4 +/- 25.4 g/m2) and posterior wall thickness (3.37 +/- 0.47 mm to 4.63 +/- 0.58 mm) was recorded. Left ventricular end-diastolic internal diameter increased in all except the two switch failures. In all the successful cases the left ventricle had assumed a circular shape on cross-section with the interventricular septum contracting in synergy with the left ventricular mass. In the two failures, however, the interventricular septum had remained flat. CONCLUSIONS: Echocardiography can be used reliably in surgical decision making in rapid two-stage arterial switch operation. Increase in left ventricular mass, left ventricular posterior wall thickness, and left ventricular end-diastolic internal diameter toward normal combined with an acquisition of circular left ventricular configuration with the interventricular septum contracting in synergy with the left ventricular mass appear to best predict successful outcome.

Anastomosis, Surgical↗
PubMed1995

Univentricular repair. Early and midterm results.

A total of 202 patients (62 with tricuspid atresia and 140 without tricuspid atresia) underwent univentricular repair at our unit from January 1990 to September 1994. Of these patients, 182 had nonfenestrated and 20 had fenestrated interatrial baffles. Early mortality was 15.9% (29/182) in the group with nonfenestrated baffles and 5% (1/20) in the group with fenestrated baffles. The follow-up period ranged from 2 to 58 months. Seven late deaths occurred, and five patients were lost to follow-up. Of 160 patients who have been evaluated in the outpatient department in the past 3 months, 142 (88.75%) required no cardiac medicines and were in functional class I. Risk factors analyzed for early mortality and significant effusion were age, preoperative diagnosis, type of Fontan modification, cardiopulmonary bypass time, aortic crossclamp time, pulmonary artery size, associated pulmonary arterioplasty, takedown of systemic-pulmonary artery shunt, and pulmonary artery debanding, along with the Fontan operation. Bypass time exceeding 120 minutes was associated with a higher early mortality (12/47 vs 18/155; p = 0.0187). Bypass time exceeding 120 minutes (p = 0.0456) and aortic crossclamp time exceeding 60 minutes (p = 0.0278) were associated with significant postoperative effusion. Other factors were not associated with any significantly increased risk for early mortality or postoperative effusions. Fenestration of the interatrial baffle appeared to decrease early mortality, although the numbers are too small to be statistically significant. The prevalence of effusions did not differ significantly between the group with fenestrated baffles and the group without fenestrated baffles.

Cardiopulmonary Bypass↗
PubMed1995

The use of fluorophore-containing spin traps as potential probes to localize free radicals in cells with fluorescence imaging methods.

Central to the study of free radical processes is the ability to identify and localize their cellular site of formation. Under the best of experimental conditions, spin trapping/ESR spectroscopy can only characterize intracellular production of specific free radicals and confocal microscopy can only localize the site of their formation. In this article, we report on the development of a fluorophore-containing nitrone, alpha-[4-[5-((2-carboxy)phenyl)-5-hydroxy-4-oxo-3-phenyl)-2-pyrrolin+ -1-yl]phenyl]-N-(tert-butyl)nitrone sodium salt (4). This nitrone (4) reacts with alpha-hydroxyethyl radical with a second order rate constant of 1.7 x 10(5) M-1 s-1 to give a characteristic ESR spectrum. However, we were unable to decrease the fluorescence emission, due in part to the small concentration of nitroxide generated from the reaction of alpha-hydroxyethyl radical with nitrone (4). Using the fluorophore-containing nitroxide (7) as a model, we found that only 12% of the nitroxide needs to be reduced to give an almost 400% increase in the fluorescent emission of (7). Our findings suggest new approaches to the development of various fluorophore-containing nitrones that can both characterize specific free radicals and localize their site of intracellular formation.

Electron Spin Resonance Spectroscopy↗
PubMed1995

Orthotopic pulmonary valve replacement with a homograft.

Eight pulmonary valve replacements (PVR) have been performed from January 1992 to October 1994. Three patients (mean age 7.7 years, range two to 16 years) had absent pulmonary valve with tetralogy of Fallot and underwent primary PVR at the time of surgical correction. Five other patients, who had correction of tetralogy of Fallot (four cases) and of double outlet right ventricle with ventricular septal defect and pulmonary stenosis (one case), were reoperated for pulmonary regurgitation with progressive right ventricular dysfunction. Mean age at the time of reoperation was 18 years (range seven to 34 years). There was no early death. Early postoperative recovery was satisfactory in all of them. The follow up ranges from six to 35 months (mean 19 months). Seven patients were in functional class I and one in functional class II when they were last evaluated in the out-patient department and five of them were off diuretics and vasodilator. In the presence of right ventricular dysfunction pulmonary regurgitation is poorly tolerated. A competent and non-obstructive pulmonary valve is often life saving in these critically ill patients.

Adolescent↗
PubMed1994

Regional organisational audit of district departments of public health.

Organisational audit of public health in the United Kingdom is rare. To provide a framework for a structured organisational audit in district public health departments in one region organisational factors contributing to efficient, high quality work were identified and compared between districts, enabling each department to identify its organisational strengths and weaknesses. A draft list of organisational factors, based on the King's Fund organisational audit programme, were rated by 52 public health physicians and trainees in 12 district public health departments in South East Thames region for their importance on a scale of 0 (not relevant) to 5 (vital). Factors with average ratings of > 4, judged to be "vital" and proxies for standards, were then used to compare each district's actual performance, as reported by its director of public health in a self reported questionnaire. In all, 37 responses were received to the rating questionnaire (response rate 71%) and 12 responses to the directors' questionnaire. Of the 54 factors identified as vital factors, 20(37%) were achieved in all 12 districts and 16(30%) in all but one district; 18 were not being achieved by two (33%) districts or more. Overall, vital factors were not being achieved in 9% of cases. The authors concluded that most departments are achieving most vital organisational factors most of the time, but improvement is still possible. The results have been used as a basis for planning the organisation of public health departments in several of the newly formed commissioning agencies. This was the first regional audit of public health of its kind performed in the region and it provided valuable experience for planning future regional audit activity.

Health Facilities↗
PubMed1993

A fluorophore-containing nitroxide as a probe to detect superoxide and hydroxyl radical generated by stimulated neutrophils.

Toward the development of a fluorescence assay in combination with confocal microscopy to image free radicals generated by cells, we synthesized a fluorophore-nitroxide, 5-((2-carboxy)phenyl)-5-hydroxy-1-((2,2,5,5-tetramethyl-1-oxypyrrolid in-3- yl)methyl)-3-phenyl-2-pyrrolin-4-one sodium salt, and tested the applicability of this probe to detect oxygen-centered free radicals. The reaction of the fluorophore-nitroxide with superoxide (10 microM/min) generated either by the reaction of xanthine oxidase on xanthine or by PMA-activated neutrophils in the presence of cysteine (200 microM) resulted in a loss of electron spin resonance (ESR) signal intensity concurrent with an increase in fluorescence emission. The decrease in ESR signal and the augmentation in fluorescence emission were inhibited by the addition of superoxide dismutase. This fluorophore-nitroxide also reacted with methyl radical generated by the reaction of hydroxyl radical with DMSO (0.14 M). In this case a loss in ESR signal intensity concomitant with an increase in fluorescence emission which were inhibited by catalase (300 U/ml), was recorded. These results clearly demonstrated the feasibility of using fluorescence methodology in conjunction with a fluorophore-nitroxide to detect oxygen-centered free radicals in biological systems.

Electron Spin Resonance Spectroscopy↗