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Biomedical subjects

S Gupta

Publications and source records attributed to S Gupta.

At least 1,279 records · Page 71Linked to original sources
PubMed1990

Biophysical and biological activity of a synthetic 8.7-kDa hydrophobic pulmonary surfactant protein SP-B.

We have synthesized pulmonary surfactant apoprotein SP-B peptides by solid-phase chemistry and demonstrated their ability to enhance the surface-active properties of synthetic lipid mixtures. The synthetic peptides were reactive with antiserum generated against the native bovine surfactant peptide. Both peptides conferred surfactant-like properties to synthetic lipid mixtures as assessed by a Wilhelmy balance and pulsating bubble surfactometer. Likewise, mixtures of synthetic SP-B peptides and lipid restored compliance of isolated surfactant-deficient rat lungs. This work demonstrates the utility of SP-B as a functional component of pulmonary surfactant mixtures for treatment of respiratory distress syndrome or other disorders characterized by surfactant deficiency.

Amino Acid Sequence↗
PubMed1990

The effect of histamine on the immune response of hamsters to infection with Ancylostoma ceylanicum.

The role of histamine in modulating the immune response of hamsters infected with Ancylostoma ceylanicum (hookworm) was investigated. Histamine administration (20 mg base/hamster x 6 ip) made the immune hamsters susceptible to challenge infection, and on assay the humoral as well as the cell-mediated responses were found to be suppressed. An adverse effect of histamine was observed on lymphocytes but the macrophage function remained unaltered, since the latter lack histamine receptors. These findings provide definite evidence that histamine suppresses specific immune responses, and that contrary to earlier reports this neurotransmitter does not play a direct role in the 'self-cure' phenomenon.

Ancylostomiasis↗
PubMed1990

Spontaneous reactivation in chronic hepatitis B: patterns and natural history.

We identified spontaneous reactivation of hepatitis B virus (HBV) retrospectively by utilizing serum alanine aminotransferase and HBV DNA in 19 men (79% homosexual), with an estimated annual incidence of 7.3%. In 11 patients, spontaneous reactivation occurred as a single episode and in eight patients, reactivation was recurrent, with two to five episodes each. The mean serum alanine aminotransferase level was elevated over 10-fold at the peak of reactivation. Serum anti-HBc IgM was detected during 73% of the reactivation episodes. Actuarial analysis revealed that reactivation was long lasting with 45% and nearly 20% of episodes continued after 6 and 24 months, respectively. The course of 24 chronic HBV carriers with a negative serum HBV DNA test and normal alanine aminotransferase levels at initial appearance was unremarkable. We could not identify clinical features predictive of reactivation or its resolution. Severe reactivation hepatitis occurred in three patients (10%), with two deaths (6%). None of the patients lost HBsAg. Spontaneous reactivation in chronic hepatitis B can appear variably, persist long term, recur, and be fatal. Therefore, accurate classification of chronic HBV infection requires prolonged observation, and spontaneous reactivation should be considered a variable in therapeutic trials for chronic hepatitis B.

Adult↗
PubMed1990

Role of insects as inhalant allergens in bronchial asthma with special reference to the clinical characteristics of patients.

The whole body extracts (WBEs) of 13 common insects from Delhi, namely Musca domestica (house fly); Sitophilus oryzae (rice weevil); Callosobrochous maculatus (pulse beetle); Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti (mosquitoes); Blattella germanica and Periplaneta americana (cockroaches: male, female and nymph); Spodoptera litura and Heliothis armigera (moths), were prepared to evaluate their allergenic significance in patients with allergic bronchial asthma. Intradermal (ID) tests were performed with these WBEs on 75 patients with bronchial asthma and 20 healthy non-allergic volunteers. An ID test was considered positive when the weal diameter was more than twice that of phosphate-buffered saline control and at least 6 mm in size and an erythema of more than 15 mm. In the patients 27.7% of the ID tests performed were total positive (1+ to 4+) as compared to 7.1% in the controls. Ten point two per cent of ID responses were markedly positive in asthmatics (2+ to 4+) as against none in controls. Of the 13 bronchial provocation tests (BPTs) performed on patients giving positive cutaneous responses, eight (61.5%) were positive. Similarly, RASTs were positive in 87.5% of the limited sera tested from the patients with positive ID responses. The patients with a positive family history of allergic disorders gave higher percentages of positive ID responses as compared to the asthmatics with no family history. Similarly, the ID positivity was significantly higher in patients with associated allergic diseases like allergic rhinitis as compared to the patients with bronchial asthma alone. Interestingly, we observed significantly higher ID response to insects in seasonal asthmatics.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Bilateral angiosarcoma of the breast: an overview.

Angiosarcoma of the breast is a rare and aggressively malignant tumour. A case of a young lady presenting with bilateral mammary angiosarcoma and associated pregnancy is reported. Only one such case is documented in the literature. Existing literature is also reviewed. The often deceptively benign histological appearances which are extremely variable demand serious suspicion of angiosarcoma when confronted with an angiomatous lesion of the breast. Early and complete surgical excision is the treatment of choice, and adjuvant chemotherapy may have a role in the treatment. Histological grading is the most important prognostic factor with poor grades having an unfavourable outlook.

Adolescent↗
PubMed1990

Capping of mammalian U6 small nuclear RNA in vitro is directed by a conserved stem-loop and AUAUAC sequence: conversion of a noncapped RNA into a capped RNA.

The cap structure of U6 small nuclear RNA (snRNA) is gamma-monomethyl phosphate and is distinct from other known RNA cap structures (R. Singh and R. Reddy, Proc. Natl. Acad. Sci. USA 86:8280-8283, 1989). Here we show that the information for capping the U6 snRNA in vitro is within the initial 25 nucleotides of the U6 RNA. The capping determinant in mammalian U6 snRNA is a bipartite element--a phylogenetically conserved stem-loop structure and an AUAUAC sequence, or a part thereof, following this stem-loop. Wild-type capping efficiency was obtained when the AUAUAC motif immediately followed the stem-loop and when the gamma-phosphate of the initiation nucleotide was in close proximity to the capping determinant. Incorporation of a synthetic stem-loop followed by an AUAUAC sequence is sufficient to covert a noncapped heterologous transcript into a capped transcript. Transcripts with the initial 32 nucleotides of Saccharomyces cerevisiae U6 snRNA are accurately capped in HeLa cell extract, indicating that capping machinery from HeLa cells can cap U6 snRNA from an evolutionarily distant eucaryote. The U6-snRNA-specific capping is unusual in that it is RNA sequence dependent, while the capping of mRNAs and other U snRNAs is tightly coupled to transcription and is independent of the RNA sequence.

Base Sequence↗
PubMed1990

Increased leukocyte phospholipase A2 activity and plasma lysophosphatidylcholine levels in asthma and rhinitis and their relationship to airway sensitivity to histamine.

This study was carried out to determine leukocyte phospholipase A2 (PLA2) activity and plasma lysophosphatidylcholine (LPC) levels in normal subjects and in patients with asthma and rhinitis and to examine their relationship to airway sensitivity to histamine. Leukocyte PLA2 activity and plasma LPC levels were highly correlated (rs = 0.90), and were found significantly raised in both the disease groups, more so in the asthmatics. Both PLA2 activity and LPC levels showed overall negative correlations with the log dose of histamine producing a 35% fall in specific airway conductance (PD35 histamine) when the patients and the normal subjects were examined together (rs = -0.77 and rs = -0.83, respectively). The patients with leukocyte PLA2 activity more than 1.8 U (nmol 14C-AA released/mg protein/10 min at 30 degrees C) or plasma LPC levels more than 8.7% of total phospholipids (mostly asthmatics) showed high airway sensitivity to histamine (PD35 histamine less than or equal to 1 mg/ml). On the other hand, the PD35 histamine values of patients with leukocyte PLA2 activity equal to or less than 1.96 U or plasma LPC levels equal to or less than 8.7% overlapped with those of normal subjects in the range of 1.2 to 10 mg/ml. Lowering of plasma LPC levels, which probably reflect tracheobronchial LPC content as shown in guinea pigs, seems to be an essential step in the return of airway reactivity toward normal.

Adult↗
PubMed1990

Psychosocial development in a genetic male surgically reassigned as a female at birth.

This paper explores the psychological development of a child who is genetically a boy (Chromosome 46XY). However, because of multiple defects, a decision was made at birth to assign the child the gender status of a girl. Research has shown that the gender-feedback effect resulting from parent-and-infant interaction even at an early age leads to the development of sexual differences in behavior. Based on this conceptual framework, this paper investigates the complex interaction of the forces that shape sexual nature. It examines the process by which this 11-year-old girl is attempting to establish her gender identity. This paper also explores the conflicts resulting from the discordance between gender and identity, and the expression of this in developmentally regressive behavior and intellectual underachievement.

Anxiety, Castration↗
PubMed1990

Long-term reproducibility of respiratory gas exchange measurements during exercise in patients with stable cardiac failure.

Present-day technology has greatly facilitated the monitoring of respiratory gas exchange in the clinical exercise laboratory. Despite the growing use of these techniques to assess the severity and progression of disease or therapeutic response in patients with heart failure, the long-term reproducibility of oxygen uptake (VO2), carbon dioxide production, minute ventilation, heart rate (HR), and blood pressure at rest and during incremental exercise in such patients, to our knowledge, has not been evaluated. Therefore, the purpose of this study was to quantify the reproducibility of these variables along with exercise duration, maximum VO2 (VO2max) and anaerobic threshold in a group of 16 patients (61 +/- 7 years, 14 male) with chronic, stable cardiac failure of varying severity and etiology who had five or more incremental treadmill exercise tests over a period of time that ranged from 3 to 22 months. For each variable, reproducibility was represented by the coefficient of variation (CVAR). Except for exercise duration, CVAR was not a function of the severity of heart failure and, for all variables, patient-to-patient variation in CVAR was approximately 9 percent. The maximum CVAR for HR, systolic blood pressure, VO2, and VO2max was generally below 10.5 percent and for exercise duration and anaerobic threshold it was less than 12.5 percent. Based on this retrospective analysis, it is concluded that reproducible respiratory gas exchange and HR exercise responses are obtainable over extended periods of time in patients with stable, chronic cardiac failure. Exercise duration, however, is less reproducible in patients with moderate to severe failure.

Aged↗
PubMed1990

Changes in glucose/amino acid/calcium uptake and brush-border membrane-associated enzymes in rat small intestine after the administration of embelin (plant benzoquinone), an antifertility agent.

Administration of Embelin, an experimental antifertility agent, to male rats (20 mg/kg body wt/day, daily for 15 and 30 days), caused an elevation in the uptake of D-glucose, L-alanine, L-leucine, and calcium in the small intestinal segments. An increase was also noted in the intestinal brush border membrane (BBM)-associated enzymes, sucrase, lactase, maltase, alkaline phosphatase, and leucine aminopeptidase in both the intestinal homogenates and partially purified BBM preparations, particularly after 30-day administration of the drug. Embelin treatment also caused a significant increase in the microsomal glucose-6-phosphatase and the cytosolic enzyme, lactate dehydrogenase. In the Embelin-treated animals BBM-associated total lipids, phospholipids, cholesterol, triacylglycerol, unesterified fatty acids, ganglioside-sialic acids as well as the cholesterol/phospholipids molar ratio showed a considerable increase. All these changes in the Embelin-treated animals were restored back to the normal or near normal biochemical makeup when the drug therapy was withdrawn and the animals were allowed to recover for another 15 and 30 days, respectively.

Alkaline Phosphatase↗
PubMed1990

Metronidazole cost containment: a two-stage intervention.

A two-stage intervention was undertaken to extend the dosing interval of metronidazole--from the typically prescribed q6h or q8h regimen to a q12h dosing interval. Following an 2-week informational period, all prescriptions for parenteral metronidazole specifying a dosage interval of 8 hours or less were modified to 12-hour dosage intervals, unless overridden by the prescriber. Prescriptions for the 6-month periods prior to and following the intervention were reviewed to assess its impact on prescribing patterns and cost containment. The incidence of regimens involving 12-hour intervals increased from 5 to 95% following the intervention. A 2-year general hospital/drug utilization health record screen found no drug substitution effect, nor any change in postoperative infection rate or death among metronidazole recipients. Overall, the two-stage intervention was a well-accepted and effective means of cost containment, resulting in an estimated yearly cost savings of $28,000.

British Columbia↗
PubMed1990

Elevated level of hyaluronic acid binding protein in diabetic rats.

Hyaluronic acid binding protein (HABP), an extracellular matrix glycoprotein which interacts specifically with hyaluronic acid (HA) has been purified to homogeneity by HA affinity chromatography. Antibody was raised against it and the specificity of antibody towards HABP was confirmed by western blot analysis. A specific and sensitive assay method has been developed adopting solid phase non-competitive double sandwich method of ELISA. This new assay method enabled us to determine the levels of HABP in different tissue extracts of normal, diabetic and reverse diabetic rats. A significant increase in the levels of HABP was observed in diabetic animals, which however attained normal levels with insulin treatment.

Animals↗
PubMed1990

Species differences in chlorethylclonidine antagonism at vascular alpha-1 adrenergic receptors.

Chloroethylclonidine (CEC) inhibition of norepinephrine-induced contractile response was studied in rat and rabbit aorta. CEC inhibition was irreversible, but displayed a competitive pattern characterized by rightward shifts of the norepinephrine EC50 with little or no decrease in maximum response. CEC appeared to shift response to a discrete but lower affinity state. The time course for irreversible inhibition by 10 microM CEC was faster for rat aorta (T1/2 = 18 min) than for rabbit aorta (T1/2 = 118 min) indicating a difference either in receptor occupation or in the rate of alkylation after occupation. Measurements of reversible CEC affinity in rabbit aorta yielded a pKB of 6.3 and the rate of alkylation was not significantly increased at 100 microM CEC so that lower occupation could not account for the difference. Pretreatment with phenoxybenzamine significantly increased the sensitivity of rabbit aorta to CEC indicating a role for receptor reserve in determining the extent of CEC inhibition. Membrane fluidity measured by diphenylhexatriene fluorescence was lower in rabbit than rat aorta; however, dimethylsulfoxide or ethanol failed to alter the rate of irreversible CEC inhibition in the rabbit. Protein kinase C activation with phorbol dibutyrate failed to alter CEC alkylation in rabbit aorta. WB 4101 [2-(2,6-dimethoxyphenoxyethyl)-aminomethyl-1,4-benzodioxane] affinity was higher in rabbit aorta (pKB = 8.9) than rat aorta (pKB = 8.3) consistent with a contribution of alpha-1A and alpha-1B adrenergic receptor subtypes to differences in CEC sensitivity, although the difference was not as great as would be predicted.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Antagonists↗
PubMed1990

Action of methylglyoxal bis (guanyl hydrazone) and related antiprotozoals on Acanthamoeba culbertsoni.

Methylglyoxal bis(guanyl hydrazone) (MGBG) and the related diamidine compounds berenil and pentamidine inhibited multiplication of A. culbertsoni. The growth inhibition by MGBG (2.5 mM) in the peptone medium was accompanied by the disappearance of spermidine and a marked reduction in the level of diaminopropane. MGBG and berenil completely inhibited growth in a chemically defined medium at 1 mM and 1-2 microM concentration, respectively. However, there was no decrease in the polyamine levels in the early stages of growth inhibition by these agents. Uptake of putrescine, spermidine and spermine by A. culbertsoni has been demonstrated but addition of exogenous polyamines did not reverse the growth inhibitory action of MGBG and berenil. Inhibition of S-adenosylmethionine decarboxylase and decrease in polyamine synthesis do not seem to be the primary targets for the antiamoebic action of MGBG and berenil.

Acanthamoeba↗