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Biomedical subjects

M Lal

Publications and source records attributed to M Lal.

At least 19 recordsLinked to original sources
PubMed2001

Ouabain, a steroid hormone that signals with slow calcium oscillations.

The plant-derived steroid, digoxin, a specific inhibitor of Na,K-ATPase, has been used for centuries in the treatment of heart disease. Recent studies demonstrate the presence of a digoxin analog, ouabain, in mammalian tissue, but its biological role has not been elucidated. Here, we show in renal epithelial cells that ouabain, in doses causing only partial Na,K-ATPase inhibition, acts as a biological inducer of regular, low-frequency intracellular calcium ([Ca(2+)](i)) oscillations that elicit activation of the transcription factor, NF-kappa B. Partial inhibition of Na,K-ATPase using low extracellular K(+) and depolarization of cells did not have these effects. Incubation of cells in Ca(2+)-free media, inhibition of voltage-gated calcium channels, inositol triphosphate receptor antagonism, and redistribution of actin to a thick layer adjacent to the plasma membrane abolished [Ca(2+)](i) oscillations, indicating that they were caused by a concerted action of inositol triphosphate receptors and capacitative calcium entry via plasma membrane channels. Blockade of ouabain-induced [Ca(2+)](i) oscillations prevented activation of NF-kappa B. The results demonstrate a new mechanism for steroid signaling via plasma membrane receptors and underline a novel role for the steroid hormone, ouabain, as a physiological inducer of [Ca(2+)](i) oscillations involved in transcriptional regulation in mammalian cells.

Animals↗
PubMed2001

Cryopreservation of Rh negative blood for improved storage & utilisation by means of indigenous freezing bags & solutions & manual deglycerolisation.

BACKGROUND & OBJECTIVES: Cryopreservation allows donor blood to be stored for years, rather than weeks as in liquid storage. This is an established procedure in countries with a developed blood transfusion service. Cryopreservation has not been introduced in India, possibly because of the presumed high cost and complexity of the procedure. An attempt is made in this study, to cryopreserve Rh negative blood in a mechanical freezer using indigenous bags and solutions and manual deglycerolisation to reduce the cost of preservation. METHODS: RBCs to be frozen were weighed and transferred by sterile welding to an 800 ml freezing bag. Based on RBC weight, 400-500 ml of glycerol (5.7 MpH 6.8) was added as cryopreservative. After extracellular and intracellular equilibration, excess glycerol was removed by centrifugation. Glycerolised RBCs were frozen at -80 degrees C in a mechanical freezer. Cryopreserved units were thawed at 37 degrees C and deglycerolised. Twenty one patients were transfused with the frozen deglycerolised RBCs after the usual pre-transfusion tests. RESULTS: Haematocrit (Hct) values of the frozen deglycerolised units, complied with required standards, before addition of glycerol and post glycerolisation. RBC recovery was more than 80 per cent and Hct 83.3 per cent after deglycerolisation. Twenty one patients transfused with the frozen deglycerolised blood experienced no adverse effects and showed a 24 h mean post transfusion Hb increment of 0.73 g/dl. INTERPRETATION & CONCLUSION: Cryopreservation, unlike liquid storage, allows Rh negative blood of the required ABO groups to be stocked. Cryopreservation also improves its utilisation, reduces wastage and helps supplement the liquid stocks of Rh negative blood. The use of indigenous freezing bags and manual deglycerolisation has resulted in an inexpensive procedure, which can be integrated, with minor inputs, into any blood bank that is already preparing blood components.

ABO Blood-Group System↗
PubMed2001

A comparison of cardiovascular risk factors among Indo-Asian and caucasian patients admitted with acute myocardial infarction in Kuala Lumpur, Malaysia and Birmingham, England.

Indo-Asians in the UK are at an increased risk of coronary artery disease (CAD); this may be a reflection of their cardiovascular risk factor profile as well as of a more sedentary lifestyle. We hypothesised that Indo-Asians in Malaysia and the UK may exhibit a similar cardiovascular risk factor and physical activity profile, which would be more adverse compared with caucasians. We studied 70 consecutive Indo-Asian patients admitted to hospitals in Kuala Lumpur, Malaysia (n=42; 35 males; mean age 60.6 years, SD 11.8); and Birmingham, England (n=28; 20 males; mean age 60.8 years, SD 12.9). Both groups of Indo-Asian patients were compared with 20 caucasian patients (13 males; mean age 62.7 years, SD 9.4) admitted with myocardial infarction from Birmingham. There was a higher prevalence of diabetes among Indo-Asians in both countries than among caucasians (p=0.0225). By contrast, caucasians had a higher prevalence of hypercholesterolaemia (p=0.0113), peripheral vascular disease (p=0.0008), regular alcohol consumption (p<0.0001) and family history of CAD (p=0.0041). There were no significant differences in mean age, body mass index or blood pressures. There was a significantly lower leisure activity score (p=0.001) and total physical activity score (p=0.003) among Indo-Asians in both countries than among caucasians. This survey has demonstrated differences in cardiovascular risk factors among Indo-Asian and caucasian patients. The high prevalence of diabetes, as well as the lower physical activity and sedentary lifestyles among Indo-Asians, in both Malaysia and the UK, may in part contribute to the high incidence of CAD in this ethnic group.

Aged↗
PubMed2001

Clinical evaluation of sibutramine in obese type 2 diabetic patients refractory to dietary management.

MATERIAL AND METHODS: An open, non-comparative study was carried out to assess the efficacy and toleration profile of sibutramine, a new antiobesity drug, in promoting weight loss in obese type 2 diabetes mellitus subject who failed to reduce weight after strict dietary control. Twenty seven patients completed the study. Sibutramine was started as a single morning dose of 10 mg and was subsequently increased to 15 mg daily if weight loss was not satisfactory. The total duration of the study was twelve weeks with followup at every four weeks. Effect of drug was monitored in terms of weight reduction, changes in body mass index, waist circumference, hip circumference, waist/hip ratio and other metabolic parameters. A fixed dietary prescription and concomitant therapy with drugs, if required and not likely to interfere with the trial therapy, was permitted but was not changed during the study period. RESULTS: At the end of 12 week, mean weight reduction in study subjects was 4.16 kg (p < 0.001), the corresponding BMI decreased by 1.6 (p < 0.0001) and hip circumference by 3.68 (p < 0.001). However, there was no significant change in fasting blood glucose and Hb(A1c) values. CONCLUSION: The study indicates sibutramine to be an effective and well tolerated agent leading to significant reduction in parameter of obesity in obese type 2 diabetic subjects.

Adult↗
PubMed2001

Teenage pregnancies in the Rewa medical sub-division, Fiji.

To assess the magnitude of teenage pregnancies in the Rewa Medical Sub-division as well as the socio-demographic characteristics of the affected teenagers so as to provide a baseline for tackling the problem. The study was a 5 year retrospective study (1994-1998) of the medical records of the Nausori Maternity Unit, the only unit for these purposes in the entire Subdivision. Pregnancies that were intentionally terminated were not included, as no such data was available from these our public health services. An average of 11.1% of the 5319 obstetric patients attended to at the centre for the 5 years were teenagers. Their age range was 13 to 19 years. Proportionately more Fijians had such teenage pregnancies than their Indo-Fijian counterparts. The same was true of their being unmarried or being VDRL positive. A larger percentage of the Indian teenagers received assisted deliveries than the Fijians, but this was not statistically significant, being 6% and 4% respectively. Low birth weight was 19% among these teenagers (compared with 5.9% overall). Efforts are needed in the area of family life education to improve on aspects of teenage pregnancies. Since this is an area of education that has many conflicting values in the modern world, it is advocated that parents as well as many agencies as possible should be targets as well as join in this task in order meet the needs as due. Such education should cover and respect all the values concerned.

Adolescent↗
PubMed1999

Management of ventricular septal defect: a survey of practice in the United Kingdom.

BACKGROUND: A survey of pediatric cardiac surgeons was performed to establish current opinions in the United Kingdom concerning closure of ventricular septal defect. METHODS: Questionnaires were sent to 14 pediatric cardiac centers in 1995 (16 surgeons, 100% response), and again in 1997 (20 surgeons, 100% response). RESULTS: Results are presented for 1997, with findings from 1995 shown in parentheses. Eleven (6) surgeons used bypass exclusively, 9 (10) sometimes used circulatory arrest. Operative techniques were similar, although the material used for the patch varied. Multiple defects were approached via the transatrial route by 18 (15), right ventriculotomy by 11 (7) and left ventriculotomy by 7 (6). The juxta-arterial defect was approached via the transpulmonary route by 16 (13), a combination by 9 (11), transatrial by 10 (6), and transventricular by 9 (5). The most common indications for pulmonary arterial banding were "Swiss cheese" defect for 13 (13), and functionally single ventricle for 5 (6). Ventricular septal defect associated with coarctation was repaired in two stages by 13 (10), a single stage by 5 (3), or either by 1 (3). CONCLUSIONS: Pediatric cardiac surgeons in the United Kingdom demonstrate a uniform, evidence-based approach to the management of ventricular septal defect.

Aortic Coarctation↗
PubMed1997

Is there such a thing as the "tendon of the infundibulum" in the heart?

The fibrous skeleton of the heart has featured prominently in anatomical and surgical descriptions, although all its purported components are difficult to demonstrate. In descriptions of the skeleton, there have been repeated references to the presence of a tendon (or ligament) between the aortic and pulmonary roots. Such a tendon is rarely, if ever, discussed in the context of surgical procedures being carried out on the ventricular outflow tracts. Our study was undertaken, therefore, to investigate the existence and nature of such a tendon or ligament. Serial transverse sections were made through roots of aorta and pulmonary trunk in an intact fetal heart. In addition, ten normal adult hearts were dissected to display the components of the fibrous skeleton of the heart. No discrete fibrous or elastic structure could be detected in the tissue plane between the aortic sinuses and the subpulmonary muscular infundibulum, although a fascial strand was observed in one heart. Apart from this specimen, the space between the free-standing muscular subpulmonary infundibulum and the sinuses of aorta hearing the coronary arteries was occupied only by loose fibroareolar tissue. The initial presence of the ligament was described following studies of animal and macerated human hearts. Subsequently, it would seem its existence has been passed down through generations of morphologists and surgeons without its presence being reconfirmed. We have been unable to demonstrate any structure approximating to the initial illustrations.

Aortic Valve↗
PubMed1996

Anatomy of the aortic root with particular emphasis on options for its surgical enlargement.

BACKGROUND AND AIMS OF THE STUDY: The aortic root is a frequent site of surgical intervention, both in adults and children, yet there is ambiguity about the precise nature and relation of the various structures composing the aortic root. The present review aims to clarify these ambiguities and to explain the morphological basis of surgical procedures for enlargement of the aortic root. MATERIALS AND METHODS: Using autopsied specimens of normal hearts, the morphology of the attachment of the leaflets, the interleaflet triangles and the circular ventriculo-arterial junction of the aortic root were studied in detail, paying special regard to fibrous and muscular continuity, relation to the atrioventricular conduction axis, and the coronary arterial branching. Surgical dissections and incisions required for enlargement of the aortic root were simulated in these specimens. RESULTS: It was evident that the locus of attachment of aortic valvar leaflets takes the form of three (semilunar) crescents. This attachment is not circular, as the word 'annulus' suggests, neither does it correspond to the anatomical ventriculo-arterial junction. During implantation of a mechanical valve in the aortic position, a circular prosthetic valve ring is sutured on to the attachments of the native valvar leaflets. This must entail some distortion when the sutures are tied. Analysis of autopsied specimens showed that, on completion of the process of suturing, the location of the prosthetic valve is close to the anatomic ventriculo-arterial junction-one of the true annular regions of the aortic root. CONCLUSIONS: The continuity of the aortic valvar leaflets and the interleaflet triangles with structures such as the aortic (anterior) leaflet of the mitral valve posteriorly, and with the muscular ventricular septum anteriorly, provide an opportunity for surgeons to enlarge the aortic root by widening of the anatomic ventriculo-arterial junction.

Adult↗
PubMed1996

Prevalence of multi-drug resistant Salmonella typhi in Ludhiana Punjab.

A total of 945 strains of S. typhi isolated from blood cultures during 1989 to 1994 were studied. Their antibiotic susceptibility showed 580 (61.4%) of strains to be multidrug resistant. The 464 strains tested for their susceptibility to ciprofloxacin were all sensitive to the drug. Twenty three (17.9%) of the 128 strains of S. paratyphi A were resistant to chloramphenicol. The sole isolate of S. paratyphi B was sensitive to all antibiotics tested.

Drug Resistance, Multiple↗