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Biomedical subjects

H Singh

Publications and source records attributed to H Singh.

At least 163 records · Page 9Linked to original sources
PubMed1996

Closed mitral valvotomy for mitral restenosis: experience in 113 consecutive cases.

The costs of heart operations and the problems related to anticoagulation after prosthetic valve replacement are among the limitations faced by patients in nonindustrialized countries with mitral stenosis caused by chronic rheumatic heart disease. The young age at which these patients are seen also compels the surgeon to preserve the native valve. The least costly and optimal way to achieve this objective is by closed mitral valvotomy. After closed mitral valvotomy, mitral restenosis is commonly encountered. We report here our 10-year experience with operation on 113 consecutive patients with mitral restenosis. Closed transventricular revalvotomy was performed with Tubbs dilator in 105 of 113 patients. Mean age was 343 years, with a male to female ratio of 1:1.5. Most patients were in New York Heart Association functional classes III and IV (74.3% and 19.4%, respectively). Mean interval between first and second valvotomy was 9.4 years, Hospital mortality rate was 2.8%, trivial postoperative mitral regurgitation occurred in 16.1%, and moderately severe regurgitation occurred in 1.9%. Early postoperative systemic embolism occurred in 3.8% of the cases. Moderate to excellent symptomatic improvement was noted in 89.4% of the cases and poor results were seen in 10.2%. Late follow-up of 76 patients ranged from 2 to 10 years (mean 3.8 years), with 39.4% patients in New York Heart Association class I and 50% in class II. Close mitral revalvotomy is thus an economical, simple, and safe palliative procedure that carries good long-term results.

Adolescent↗
PubMed1996

Patient satisfaction at health centres in Trinidad and Tobago.

The aim of this paper is to identify background characteristics of health centre users in Trinidad and Tobago and their perceptions of the services provided. Multi-staged sampling was used to select 1,500 health centre users throughout the country. Data were obtained using structured interviews conducted on regular clinic days. Results show that there is an overwhelmingly large percentage of unemployed persons (80.4%) and women (75.9%) among the users of health centres. The elderly is well represented, with 25.4 percent of the sample being over 60 years of age. Also, occupational status of family wage earners and educational attainment levels of respondents reflect a disproportionately higher number from lower socio-economic groupings among health centre users. On the other hand, proportions of different ethnic and religious groups among the respondents bear a striking similarity to the general population of Trinidad and Tobago. Respondents appear to be generally satisfied with the services of the health centres. When the categories for "satisfied' and "very satisfied' were combined, results show that 73.0% of respondents were satisfied with the comfort of the health centre, 81.7% with the ease and convenience of getting to the health centre and 67.4% with the medical care received at the health centre. According to respondents' opinions, the services in greatest need of improvement are the pharmacy and doctor services, especially through reducing the long waiting period. When the doctors, nurses and pharmacists were compared with respect to "courtesy and consideration', "Skills and Competence' and "advice provided', results show that the generally high levels of satisfaction are remarkably similar in all three cases.

Adult↗
PubMed1996

Management of asymptomatic impacted wisdom teeth: a multicentre comparison.

This study was carried out to assess the opinions of clinicians (general practitioners and oral and maxillofacial surgeons) regarding the management of unerupted Mandibular Asymptomatic Impacted Wisdom Teeth (MAIWT) at two centres: Glasgow Dental Hospital and School and its affiliated institutions and Prince Philip Dental Hospital and its affiliated institutions in Hong Kong. Twenty four clinicians, twelve from each centre, of whom six were oral and maxillofacial surgeons (OMS) and six general dental practitioners (GDP) participated in this investigation. The orthopantomographs of 21 cases were used in the study and were examined by each clinician to investigate the management of unerupted MAIWT was recorded using a custom written questionnaire. Hong Kong clinicians showed a greater tendency towards extraction of MAIWT in comparison to Glasgow clinicians. The difference was statistically significant. The data indicates a significant difference between Hong Kong OMS and Glasgow OMS and between Hong Kong OMS and Hong Kong GDP, with Hong Kong OMS showing a greater tendency towards extraction. This study proved the diversity of opinions in one of the most common dento-alveolar procedures. The dilemma to extract or retain MAIWT still exists and controversy is likely to remain. The difference in the rationale of management regimes between the centres are discussed. The medico-legal and financial issues are investigated.

General Practice, Dental↗
PubMed1996

Gene targeting reveals a hierarchy of transcription factors regulating specification of lymphoid cell fates.

Specification of B- and T-lymphoid cell fates appears to involve the expression of a shared set of genes encoding recombination proteins and of genes encoding lineage-specific components of antigen receptors. Recent studies using gene targeting have identified transcription factors that are required for the proper specification of lymphoid cell fates. On the basis of these data, a regulatory gene hierarchy which orchestrates the development of lymphoid progenitors from hematopoietic stem cells can be proposed.

Animals↗
PubMed1996

Electroencephalogram bispectral analysis predicts the depth of midazolam-induced sedation.

BACKGROUND: The electroencephalogram (EEG) has been used to study the effects of anesthetic and analgesic drugs on central nervous system function. A prospective study was designed to evaluate the accuracy of various EEG parameters for assessing midazolam-induced sedation during regional anesthesia. METHODS: Twenty-six consenting adult patients were administered 4.5-20 mg intravenous midazolam (in increments of 0.5-1 mg bolus doses every 6-10 min) until they became unresponsive to tactile stimulation (i.e., mild prodding or shaking). The EEG was continuously recorded from a bifrontal montage (FP1-Cz and FP2-Cz) to obtain the bispectral index (BI), 95% spectral edge frequency (SEF), median frequency (MF), and delta, theta, alpha, and beta power bands. Sedation was assessed clinically at 6-10-min intervals using the Observers' Assessment of Alertness/Sedation (OAA/S) scale, with 1 = no response (unconsciousness) to tactile stimulation to 5 = wide awake. The EEG parameters were correlated with the OAA/S scores using nonparametric Spearman's rank-correlation analysis. Kruskal-Wallis analysis of variance was used to determine significant changes in EEG parameters during the onset of and recovery from midazolam-induced sedation. RESULTS: Of the EEG parameters studied, the BI exhibited the best correlation with OAA/S scores during both the onset (Spearman's Rho = 0.815) and recovery (Spearman's Rho = 0.596) phases. With increasing sedation, there was a progressive decrease in the BI (OAA/S score of 5: BI = 95.4 +/- 2.3; 4: 90.3 +/- 4.5; 3:86.6 +/- 4.6; 2:75.6 +/- 9.7; 1:69.2 +/- 13.9). A similar pattern was found for the 95% SEF as the OAA/S score decreased from 4 to 1. Similarly, EEG-BI increased with recovery from the sedative effects of midazolam (OAA/S score = 2:BI = 75.2 +/- 10.2; 3:82.3 +/- 7.3; 4:90.8 +/- 6). However, no consistent changes were found with the other EEG parameters. The mean EEG values between OAA/S scores 3 and 2 and between OAA/S scores 2 and 1 during the onset and recovery phases from midazolam-induced sedation, defined as EEG50 values for response to verbal command (EEG50-VC) and to shaking of the head (EEG50-SH), were 79.3 +/- 8 and 70.8 +/- 14.3, respectively, for EEG-BI. The EEG-BI displayed the smallest coefficients of variation for the EEG50-VC and EEG50-SH values. CONCLUSIONS: The EEG-BI appears to be a useful parameter for assessing midazolam-induced sedation and can predict the likelihood of a patient responding to verbal commands or to shaking of the head during midazolam-induced sedation.

Adult↗
PubMed1996

Beta 2-adrenergic function in cultured rat proximal tubule epithelial cells.

We conducted studies to determine whether functional beta 2-adrenoceptors are present in cultured rat proximal tubule epithelial cells. To determine whether cultured cells maintain polarity with respect to sodium transport, cells were acid loaded. Acid loading resulted in stimulation of sodium transport. Exposure of acid-loaded cells to alkaline extracellular pH further enhanced sodium transport (22Na flux at pH 7.50 was 68.1 +/- 44% above pH 7.00, P < 0.05). Cultured proximal tubules also exhibited basolateral 86Rb uptake, 65% of which was ouabain sensitive. Thus cultured cells maintain apical Na/H antiport and basolateral Na-K-adenosinetriphosphatase (Na-K-ATPase). Metaproterenol (10(-6) M), a selective beta 2-agonist, stimulated Na-K-ATPase activity by 36 +/- 6% above control (P < 0.05). The stimulatory effect was blocked by ICI-118551, a selective beta 2-antagonist. To determine whether metaproterenol-dependent increases in Na-K-ATPase were dependent on apical sodium entry, apical entry was blocked with dimethylamiloride or maximized with monensin. Both dimethylamiloride and monensin prevented metaproterenol activation of Na-K-ATPase. Metaproterenol-mediated increases in Na-K-ATPase activity were associated with increases in sodium transport (27 +/- 10% above control, P < 0.05), which was prevented by dimethylamiloride. In contrast to isoproterenol, metaproterenol did not stimulate cAMP production. In summary, we have shown that functional beta 2-adrenoceptors are present on cultured rat proximal tubules. beta 2-Adrenoceptor activation results in increases in Na-K-ATPase and Na transport as a consequence of increased apical sodium entry.

Adrenergic beta-Agonists↗
PubMed1996

Introducing stress management into general practice.

The biomedical model that forms the basis of conventional medical practice is limited in its usefulness when applied to many of the presentations encountered in clinical general practice. Anxiety as a presenting symptom on its own is the fifth commonest presentation in Australian general practice. To relieve the physical symptoms is merely the first step; teaching the patient to manage the accompanying dys-stress more effectively must be an important part of our duty of care. The skills thus acquired will equip the patient to cope better with the present and subsequent health crises. A few simple exercises that I have found useful both for myself and for my patients are described. These exercises can be easily integrated into clinical practice.

Adult↗
PubMed1996

Antifungal susceptibility pattern of non-albicans Candida species & distribution of species isolated from Candidaemia cases over a 5 year period.

A marked increase in the incidence of patients of candidaemia is reported from a tertiary care hospital in north India over the last five years (15 patients in 1991 and 275 in 1995). The distribution of Candida species isolated from January 1991 through December 1995 was investigated. Antifungal susceptibility against amphotericin B, 5-fluorocytosine, ketoconazole and fluconazole of 100 randomly selected non-albicans Candida species isolated during 1995 was determined by an in-house standardized disc diffusion method and the standard broth dilution procedure recommended by the National Committee for Clinical Laboratory Standards (NCCLS, USA). The disc diffusion method correlated well with NCCLS method except for ketoconazole. Resistance against any antifungal was confirmed only by results of NCCLS method. A shift to higher isolation of non-albicans Candida species was observed during this period (52.6% in 1992 to 89.5% in 1995). Resistance was observed against 5-fluorocytosine in 3 per cent strains of C. krusei; and against fluconazole in 24.2 per cent of C. krusei, 15.4 per cent of C. guilliermondii and 5.7 per cent strains of C. tropicalis. No resistance was detected against amphotericin B and ketoconazole. Thus Candida species with fluconazole resistance have become more prominent in recent years.

Antifungal Agents↗
PubMed1996

Evidence of two catalytically active carnitine medium/long chain acyltransferases in rat liver peroxisomes.

Peroxisomal matrix proteins were extracted from the highly purified peroxisomes with sodium pyrophosphate, and the membranes were sedimented by high speed centrifugation. Biochemical marker enzyme analyses revealed a quantitative release of a number of well-known peroxisomal matrix proteins from the purified peroxisomes. In contrast, carnitine medium/long chain acyltransferase activity, assayed with decanoyl-CoA and palmitoyl-CoA as substrates, was equally distributed in the membrane and the matrix fractions. The matrix and the membrane enzyme activities were differentially affected by a number of detergents. The enzyme in the membrane fraction showed higher malonyl-CoA sensitivity compared to the enzyme in the matrix fraction. The enzyme(s) from the purified peroxisomes or the peroxisomal membranes was quantitatively solubilized by sodium cholate, and the cholate-solubilized enzyme retained malonyl-CoA sensitivity. The membrane enzyme was separated from the matrix enzyme by hydroxylapatite column chromatography. The separation of the membrane enzyme or the matrix enzyme by hydroxylapatite column chromatography resulted in loss of malonyl-CoA sensitivity. The partially purified membrane and the matrix enzymes showed broad substrate specificity, and the highest enzyme activities for both were observed with decanoyl-CoA. In contrast to the matrix enzyme, the membrane enzyme was strongly inhibited by high concentrations (> or = 50 microM) of acyl-CoAs (> 10 carbons in length). The matrix enzyme showed a 2.5-fold lower Km for carnitine compared to the membrane enzyme. The catalytic properties of the partially purified matrix enzyme appear to be similar to the well-characterized peroxisomal carnitine octanoyltransferase, though we find highest activity with decanoyl-CoA rather than octanoyl-CoA as a substrate. The data presented clearly indicate that the membrane and the matrix enzyme activities are due to different proteins.

Acyl Coenzyme A↗
PubMed1996

Isolation of poliovirus from cases of acute flaccid paralysis.

OBJECTIVE: To evaluate the frequency of isolation of polio and other viruses from fecal samples in subjects with acute flaccid paralysis in northern parts of India. SETTING: Rural and Urban Immunization Centers used for Expanded Programme on Immunization. METHODS: 219 fecal samples were collected by anal tube in 1992 from Punjab, Haryana, Himachal Pradesh and Chandigarh and processed for virus isolation. RESULTS: Of 219 fecal samples, 103 (47%) were positive for viruses in the age group of 3 mo to 5 yr. Amongst the positive samples, the predominant isolated was poliovirus type 1 (70.9%) from all the States. Non polio enteroviruses were isolated from 20.4% of fecal samples. CONCLUSION: Even though poliovirus is still the most common etiologic agent for acute flaccid paralysis in northern India, non polio enteroviruses are also emerging as important causal pathogens in this condition.

Acute Disease↗
PubMed1996

Complications of treadmill testing.

Complications occurring in 2,400 treadmill tests are reported, out of which 2107 (87.8%) were on males and 292 (12.2%) on females. The total number of patients with complications was 29 (1.2%) and the types were: acute MI in 2, ventricular tachycardia (sustained) in 3, nonsustained in 7 with ventricular couplets in 3 patients, atrial tachyarrhythmias in four of AVNRT in 2, EAT in 2, SVT with abberancy in 1, SVT (undifferentiated) in 3, bradyarrhythmias in form of sinus bradycardia in 4, hypotension in 4 and AV block in 2. There were no deaths. Only 8 (0.33%) patients required treatment-2 each of acute MI, sustained VT, AVNRT and hypotension, though only 4 of them were hospitalised (2 each of acute MI and VT) and subsequently discharged. Highest incidence of complications was seen in post MI patients (2.01%) followed by those with typical anginal pain (1.9%) and they had more serious problems in form of MI and sustained VT. 55.17% patients with complications were positive for provocative ischaemia as compared to 22.75% positivity in the total. Although 14 (38.2%) patients developed complications at workload of 4-6 METS but 2 achieved load of 10 METS also. Complications were seen mostly during exercise and also during recovery only.

Arrhythmias, Cardiac↗