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Biomedical subjects

S Dave

Publications and source records attributed to S Dave.

At least 37 records · Page 2Linked to original sources
PubMed1997

The effects on cardiac arrhythmias of antihypertensive therapy causing regression of left ventricular hypertrophy.

To examine the effects of antihypertensive therapy causing regression of left ventricular hypertrophy on cardiac arrhythmias, 26 hypertensive subjects were treated with ramipril with felodipine if required, and followed for 6 months after blood pressure control. Compared with baseline, left ventricular mass index (LVMI) was significantly reduced both at blood pressure control and after a further 6 months of treatment (baseline, blood pressure control, 6 months after blood pressure control; LVMI 142 +/- 3.6, 131 +/- 3.4, 123 +/- 3.8* g/m2, *P < .01 compared with baseline). There was a significant relationship between the decrease in systolic blood pressure and the decrease in LVMI after 6 months of blood pressure control compared with baseline (r = 0.41, P = .05). Compared with baseline, the average total number of ventricular ectopics decreased after blood pressure was controlled (88 +/- 59 and 21 +/- 12 respectively); however this reduction was not maintained after 6 months of further treatment, either before (78 +/- 50) or after drug washout (86 +/- 40). Compared with baseline (639 +/- 590) supraventricular ectopic total was not initially reduced after blood pressure control (650 +/- 604), but was reduced after a further 6 months of treatment (294 +/- 261). This reduction was maintained after drug washout (267 +/- 254), although this did not reach statistical significance. Radionuclide scanning at baseline was not a predictor of patients with the highest risk of arrhythmia and there was no correlation between improvement or worsening of a defect with changes in ventricular ectopic total. In conclusion, antihypertensive therapy with ramipril and felodipine, although causing regression of left ventricular hypertrophy did not lead to a sustained reduction in ventricular ectopic total.

Adult↗
PubMed1997

Evidence that nitric oxide inhibits steroidogenesis in cultured rat granulosa cells.

1. A few studies have shown that nitric oxide may exert cytotoxic and/or steroidogenic effects on cultured ovarian cells but the source of this factor within the ovary remains equivocal. 2. In this study we have investigated the effects of nitric oxide on progesterone secretion, cell viability and cell morphology of cultured rat granulosa/lutein cells and examined whether granulosa cells are an important source of nitric oxide. 3. Only very low or undetectable levels of nitrites were measured in granulosa/lutein-cell-only cultures, although there was a small but significant increase in nitrite release observed in granulosa/ lutein cells obtained from oestrous rats compared with those obtained from proestrous rats. 4. There was a concentration-dependent inhibition of progesterone synthesis in the presence of the nitric oxide donors sodium nitroprusside and S-nitroso-N-acetyl-penicillamine which corresponded with an increased concentration of nitrite accumulation in the culture medium. 5. High concentrations of nitrites were measured in the medium of granulosa/lutein cells co-cultured with peritoneal macrophages and progesterone synthesis was inhibited. This effect of the macrophages was partially reversed by inhibitors of nitric oxide synthesis, aminoguanidine, NG-methyl-L-arginine and NG-L-arginine-methyl-ester, and the reversal of inhibition was inversely proportional to the concentration of nitrites measured in the medium. Dose-response curves for the three drugs on the inhibition of nitrite accumulation in macrophage cultures were obtained. 6. The nitric oxide scavenger c-PTIO [2-(4-carboxy-phenyl) -4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide.potassium salt] partially reversed the effects of S-nitroso-N-acetyl-penicillamine and macrophages on progesterone synthesis in granulosa/ lutein cells. 7. With the exception of the high dose of sodium nitroprusside, there was no evidence that any of the drugs reduced cellular viability, as assessed by measurement of cellular dehydrogenases and Trypan Blue exclusion, although high concentrations of nitrite in the culture medium derived either from the nitric oxide donors or macrophages were associated with a loss of morphological luteinization. 8. Based on the available evidence, we suggest that nitric oxide can inhibit steroidogenesis and that in vivo the source of nitric oxide may be from macrophages, which invade the ovary during the periovulatory period, and/or from endothelial cells of ovarian blood vessels.

Animals↗
PubMed1997

Prognosis in familial amyotrophic lateral sclerosis: progression and survival in patients with glu100gly and ala4val mutations in Cu,Zn superoxide dismutase.

Familial amyotrophic lateral sclerosis (FALS) is an autosomal dominant neurodegenerative disorder affecting motor neurons and is associated with mutations in the Cu,Zn superoxide dismutase gene (SOD1) in a subset (approximately 15%) of FALS families. We analyzed 158 FALS patients from 27 families with mutations in SOD1. The mean age of onset was 45.5 +/- 8.9 years, and the mean duration of disease was 3.4 years. Forty-seven different mutations in SOD1 of FALS patients have been described worldwide. In North America, the ala4val mutation is the most common. In our patients, the ala4val mutation was associated with the most rapid progression of disease. The mean duration of disease was 1.0 +/- 0.4 years, which is significantly less than the mean duration of disease for FALS patients with mutations in SOD1 other than ala4val (p < 0.001). The duration of disease for the glu100gly mutation, 5.1 +/- 3.3 years, was significantly longer than the ala4val mutation (p < 0.001). We constructed Kaplan-Meier survival curves for the age of onset and duration of the disease for three groups of patients having mutations in SOD1: (1) ala4val; (2) glu100gly; and (3) ala4val, gly37arg, his43arg, gly85arg, gly93ala, glu100gly, leu106val, ile113thr, leu144phe, and val148gly, i.e., the entire patient population. There was no correlation between the genotype and the age of onset; 50% of affected individuals developed symptoms of ALS by the age of 47 years. As more data are collected, a more accurate prognostication of a patient's survival may be possible for specific SOD1 mutations.

Adult↗
PubMed1996

ATP receptor activation potentiates a voltage-dependent Ca channel in hippocampal neurons.

Activation of a purinergic P2 receptor by adenosine 5'-triphosphate (ATP) has previously been shown to open a non-selective cation channel with a reversal potential of approximately 0 mV. We examined the effect of P2 receptor activation on voltage-gated ionic currents in acutely isolated CA3 pyramidal neurons from guinea pig hippocampus using the whole-cell-patch technique. Under conditions designed to isolate current through voltage-dependent Ca channels (ICa), ATP (50 microM) potentiated ICa by 36%. This increase in ICa desensitized back to control levels within 4 min. In contrast to the non-selective cation channel, ICa elicited from a holding potential (HP) of -100 mV showed significant potentiation in response to ATP when depolarized to a test potential (TP) of -10 mV but showed no effect on ICa when the same neuron was alternately depolarized to TP = -70 mV. No change in holding current at HP = -100 mV occurred. Tail currents were unaffected by ATP exposure suggesting that ICa potentiation was not due to modulation of L-type Ca channels. This potentiation was also observed either with ATP-gamma-s, the slowly hydrolyzable ATP analog, or with ATP in the presence of alpha, beta-methylene-ADP, an ectonucleotidase inhibitor, indicating that the effects observed were not due to activation of an adenosine receptor that required ATP hydrolysis. The potentiation of ICa was not observed with the P2X agonist, beta, gamma-methylene-ATP. These results suggest that ATP receptors can modulate voltage- as well as ligand-gated channels permeable to calcium and may play an important role in the dynamics of intracellular Ca2+ in these neurons.

Adenosine Triphosphate↗
PubMed1995

Comparative assessment of small intestinal and colonic permeability in HIV-infected homosexual men.

OBJECTIVES: To investigate both small and large intestinal permeability in HIV-positive subjects, and correlate variation in intestinal mucosal abnormality with immunological and nutritional markers of HIV disease. METHODS: Small and large intestinal permeability studies were performed in 14 HIV-seropositive patients and eight healthy men. Eight out of the 14 patients had diarrhoea and all subjects were negative for enteropathogens. Small intestinal permeability was determined using the lactulose-mannitol test and large intestinal permeability using the colonic absorption of 51Cr-EDTA. In addition, CD4 cell count, beta 2-microglobulin, C-reactive protein estimation and anthropometry were carried out in all subjects. RESULTS: HIV-seropositive subjects had higher lactulose-mannitol ratios (LMR; 0.084 +/- 0.007 versus 0.013 +/- 0.0008) and lower 51Cr activity (1.986 +/- 0.066 versus 3.115 +/- 0.560) than controls (P < 0.0004 and P < 0.05, respectively). Colonic uptake of 51Cr-EDTA was no different between subjects with and those without diarrhoea (2.04 +/- 0.124 versus 1.92 +/- 0.143, P > 0.05). A negative correlation was found between LMR and 51Cr-EDTA, but only for patients with diarrhoea (r = -0.81; P = 0.015). CONCLUSION: Regional variation affecting intestinal absorptive function occurs in patients with HIV-related diarrhoea and is characterized by increased LMR and reduced colonic uptake of 51Cr-EDTA. The pathogenesis and clinical significance of such changes are unknown.

AIDS-Related Opportunistic Infections↗
PubMed1992

Combined papaverine test and radionuclide penile blood flow in impotence: method and preliminary results.

The investigation of vascular impotence requires a simple, reliable and non-invasive method of estimating penile arterial supply. A method for measuring flow to the dependent portion of the penis has been developed using technetium-labelled red blood cells (99mTc-RBC). Its use, in conjunction with the intracavernous injection of papaverine, was investigated in 32 patients with various causes of impotence. Intracavernous papaverine was administered and a pneumatic cuff was inflated around the base of the penis both to isolate the penile circulation and to prevent dispersion of papaverine. The remaining blood pool was labelled with 99mTc-RBC. A gamma camera was used to produce a time-activity curve for the penis following release of the cuff. Penile blood flow was calculated from the initial gradient of the time-activity curve. Papaverine-stimulated penile blood flow was significantly greater in patients without evidence of arterial insufficiency. None of the subjects with arterial disease achieved flows greater than 20 ml/min/100 ml, while flow in patients without arterial disease exceeded this value. Flow estimation without the use of papaverine was not able reliably to discriminate between the 2 groups. There was no difference in papaverine-stimulated blood flow between impotent subjects with veno-sinusoidal leakage, in the absence of arterial disease, and a control group who achieved full erection with papaverine. It was therefore possible, by assessing the response to papaverine and measuring arterial blood flow, to distinguish between arterial insufficiency, veno-sinusoidal leakage and non-vascular causes of impotence. The method requires little skill and can be modified for use with inexpensive equipment.

Adult↗
PubMed1992

Relationship problems between doctors and paramedical professionals working in leprosy with reference to a possible solution.

An empirical investigation was conducted on the in-group dynamics of health personnel working in leprosy. The sample populations were taken from the National Leprosy Eradication Programme (NLEP) employees of two state governments in India. They consisted of 21 doctors and 335 paramedicals, the former constituting a formal group and the latter a semiformal group. Two separate scales were developed for each of these groups to elicit information on five potential areas of intergroup relationships. The results indicated that there was very poor acceptance of the out-group and its roles, i.e. poor acceptance of the paramedicals by the doctors and vice versa. Three reasons were elicited from this study. First, doctors held their professional standing to be on a higher level than the paramedicals, leading to excessive social distancing between doctors and paramedicals. Second, multiprofessional involvement in NLEP work has increased the trend of professional overlapping, leading to a significant apprehension of the encroachment of skills. Third, there was a mutual lack of trust of each others professional skills. Despite these problems the otherwise more severe human relationship problems, such as domineering behaviour and prejudiced perception against the out-group were found to be significantly less in this study. In order to improve working relationships between these groups a method that has been used at Karigiri is recommended. The method has two parts. The first is aimed at intrapersonal understanding and the second at the development of interpersonal skills. Role play that mimics their original work situation and an analysis of case histories were the methods of teaching that were found to be more advantageous in internalizing these skills.

Allied Health Personnel↗
PubMed1991

Diagnostic value of lung clearance of 99mTc DTPA compared with other non-invasive investigations in Pneumocystis carinii pneumonia in AIDS.

Various non-invasive investigations were carried out in patients infected with HIV who had respiratory symptoms with and without pneumocystis pneumonia (with pneumonia, n = 13 (five smokers); without pneumonia, n = 22 (13 smokers]. These included chest radiography; lung function tests (forced expiratory volume in one second, forced vital capacity; transfer factor and coefficient for carbon monoxide); arterial blood gas tensions; arterial oxygen saturation at rest and on exercise; and lung clearance of diethylenetriaminepenta-acetic acid labelled with technetium-99m (99mTc DTPA). The effect of scan time (seven v 45 minutes from peak counts) and subtraction of background counts were examined. There were no significant differences between the two groups in lung function tests or arterial blood gas tensions at rest. The median clearance half time of inhaled 99mTc DTPA for the first seven minutes from peak counts was 7.2 minutes for patients with pneumocystis pneumonia and 22 minutes for those without. The median arterial oxygen desaturation on exercise was 5% in patients with pneumocystis pneumonia and 2% in those without. 99mTc DTPA lung clearance was better than the other non-invasive tests in discriminating pneumocystis pneumonia from other pulmonary disorders in patients positive for HIV. A short scan time of seven minutes was as sensitive and specific as the longer scan time of 45 minutes, and this allows the clearance of 99mTc DTPA to become a rapid screening test.

Adult↗
PubMed1991

Self-poisoning patients discharged from accident and emergency: risk factors and outcome.

In a prospective audit of 1,096 consecutive attendances by deliberate self-poisoning patients at an accident and emergency department (A&E), such patients were discharged directly from A&E on 31% of occasions. Outcome and risk were compared for patients admitted to hospital and discharged directly from A&E. In the following year repetition of self-poisoning occurred in the same proportions of patients admitted to hospital and discharged from A&E (12%, relative risk 1.02). Suicide during the following three years occurred in 1.3% of patients admitted and 1.1% of those discharged (relative risk 1.2). Patients admitted to hospital from A&E were those likely to be at greater risk: they were older, reported more physical ill-health, expressed a threat or left a note more often, and had more frequently experienced psychiatric inpatient care. Thus, nearly one-third of deliberate self-poisoning attenders were discharged from A&E; outcomes were similar despite higher risk among admitted patients, suggesting that brief admission has some benefit.

Adolescent↗
PubMed1990

Diagnostic and therapeutic hysteroscopy in the management of abnormal uterine bleeding.

Three hundred seventy cases of abnormal uterine bleeding that occurred from January 1985 to June 1989 were studied. Diagnostic and operative hysteroscopy was performed as an outpatient procedure. Included in the study were all patients with dysfunctional uterine bleeding that did not respond to progestogens for three months, patients with severe menometrorrhagia and those with postmenopausal bleeding. Patients with pregnancy-associated bleeding, obvious uterine enlargement, polycystic ovary disease and abnormal cervical smears were excluded. The ages of the patients ranged from 22 to 82 years. The uterine cavity was found to be normal in 33.51%. Polyps were found in 21.53% of cases, submucous myomata in 11.35%, endometrial hyperplasia in 22.97%, endometrial atrophy in 1.62%, synechiae in 5.67% and adenocarcinoma in 1.35%. Targeted biopsies, excision of polyps, removal of myomata (with scissors and resectoscope) and curettage were performed as necessary.

Adult↗
PubMed1985

Human mammary carcinomas in nude rats--a new approach for investigating oxygen transport and substrate utilization in tumor tissues.

A new model is presented for the study of oxygen supply and substrate utilization in human tumor tissue. In this approach human tumor material thrives in immune-deficient nude rats. The host chosen allows the continuous evaluation of all relevant parameters. From the data obtained so far it is concluded that this model is a valid tool in investigation of the metabolic status of human tumors.

Animals↗
PubMed1985

Blood flow and oxygen supply to human mammary carcinomas transplanted into nude rats.

Blood flow of human mammary carcinomas heterotransplanted into immune- deficient rnu/rnu-rats is low. It decreases further with increasing tumor wet weight, the mean value being comparable to that of mammary carcinomas in patients. The O2 consumption rate of the heterotransplanted tumors decreases with increasing tumor wet weight and again is comparable to that of mammary carcinomas in patients. Furthermore, it is directly proportional to the O2 availability which in turn is mainly determined by TBF. The O2 utilization of the human mammary carcinomas heterotransplanted into nude rats is already high in small tumors and increases only slightly with increasing tumor weight. From these results and taking into account an impairment of convective and diffusive O2 transport it can be concluded that the O2 consumption rate of the tumor cells is mostly determined by the the O2 supply and not by the actual demand of the cancer cells. This finding holds true for different tumor cell lines in different species.

Animals↗