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Biomedical subjects

M Thomas

Publications and source records attributed to M Thomas.

At least 523 records · Page 29Linked to original sources
PubMed1994

A modified curriculum for clinical pharmacology during undergraduate training in India.

The present curriculum for clinical pharmacology during undergraduate medical training appears very inadequate as evidenced from the analysis of a questionnaire sent to all medical schools in the country. Recognising the need for the subject to be taught in a meaningful way and keeping in view the suggestions made through the questionnaire, a modified curriculum and evaluation of the course that spans through the clinical years of training is presented.

Curriculum↗
PubMed1994

Neonatal screening for congenital hypothyroidism using the filter paper thyroxine technique.

A total of 25,244 full term consecutive newborns were screened for hypothyroidism at 24 to 96 h of birth using the filter paper technique for thyroxine. The screening protocol based on our pilot study considered filter paper thyroxine (FP-T4) values of 51 to 80 ng/ml (-1 SD) as borderline and < 50 ng/ml (-2 SD) as high risk for congenital hypothyroidism. FP-T4 and/or serum T4 and TSH were reestimated in all neonates with FP-T4 < 80 ng/ml. A total of 4775 (18.9%) newborns (FP-T4, 51 to 80 ng/ml in 4435 and < 50 ng/ml in 340) needed the recall; 2237 (50.4%) with FP-T4 51 to 80 ng/ml recalled by letters and 283 (83.3%) of the 340 subjects with FP-T4 < 50 ng/ml recalled by home visit, responded by 6 wk of age. Congenital hypothyroidism was confirmed in 6 newborns. FP-T4 in one persisted at 55 ng/ml on follow up and in the remainder both initial and repeat values were < 50 ng/ml. Follow up serum T4 values were subnormal (7.8-50.2 ng/ml) and serum TSH elevated (80-1233 IU/ml). Technetium thyroid scan showed agenesis in 3, ectopia in 2 and normal gland with probable dyshormonogenesis in one. Three other newborns (FP-T4 93 to 143 ng/ml) escaped primary detection and were referred later for congenital hypothyroidism. The incidence of congenital hypothyroidism by primary screening was 1:4207 (6 of 25,244) but with these 3 missed cases, probably 1:2804. Congenital hypothyroidism was reconfirmed in all 9 infants between the ages of 2 1/2 to 4 yr.(ABSTRACT TRUNCATED AT 250 WORDS)

Congenital Hypothyroidism↗
PubMed1994

Dislocation after hemiarthroplasty of the hip: a comparison of the dislocation rate after posterior and lateral approaches to the hip.

We compared the 3-month dislocation rate for hip hemiarthroplasties inserted via the posterior and direct lateral routes. In all, 2906 primary hemiarthroplasties, performed between 1986 and 1992 in four hospitals on a training hospital rotation, were analysed. The posterior approach was used in 1656 (57%) and the lateral in 1250 (43%). The groups were otherwise comparable. The overall dislocation rate for the posterior approach was 9.0% (149/1656), whereas that for the direct lateral approach was 3.3% (41/2150). The difference is statistically highly significant. In addition, we analysed the dislocation rate for each approach in the three broad groups of surgical trainee. For senior registrars, there was no statistical difference in the dislocation rate. However, for registrars and senior house officers, there were statistically highly significant differences in the dislocation rate for posterior and direct lateral approaches (8.4% vs 3.3% and 14.2% vs 3.6%, respectively). We conclude that, because of the high mortality associated with dislocation of a hemiarthroplasty, the posterior approach for this operation should now be abandoned, especially by surgical trainees early in their careers.

Aged↗
PubMed1994

Appearance of homogeneous smectic multilamellar microenvironments in biomembranes undergoing superoxide-initiated lipid peroxidation: lipid-dienyl radical accumulation and fluidity management in lipid bilayers.

Erythrocyte ghosts were exposed to various levels of oxyradical shock in order to identify the extent of accumulation of peroxidative intermediates. Malondialdehyde reacting end products were the same in all different models. But, the accumulation of dienyl radical species increased with higher intensity of oxyradical shock. These dienyl radicals may rearrange to create a homogeneous smectic multilamellar microenvironment which may be more fluid in terms of the molecular dynamics.

Erythrocyte Membrane↗
PubMed1994

Pediatric living-related and cadaveric liver transplantation: a single center experience.

Living-related liver transplantation is becoming more commonplace worldwide in the treatment of end-stage liver disease in the pediatric age group. Our LRD experience has resulted in patient and graft survival rates comparable to our cadaveric donor recipients. The incidence and severity of acute rejection episodes were similar. This differs from the clear immunologic advantage of living-related donation in kidney transplantation. It may, however, reflect the relatively small numbers in our LRD group. Overall, however, the technical complications are manageable with early intervention, yielding acceptable results.

Adult↗
PubMed1994

Freeze-thawed muscle grafting for painful cutaneous neuromas.

We used freeze-thawed muscle grafts to restore continuity to the affected nerve in 22 painful cutaneous neuromas. In 11 of the 15 neuromas in the upper limb, pain was partially or completely relieved; in six of these there was some recovery of distal sensation. Partial pain relief was achieved in only two of the seven neuromas in the lower limb. The difference is attributed to the longer grafts required in the lower limb.

Adult↗
PubMed1994

Preliminary report on cell encapsulation in a hydrogel made of a biocompatible material, AN69, for the development of a bioartificial pancreas.

The occurrence of an inflammatory reaction represents the major obstacle to the development of any implantable system including micro and macroencapsulation. The purpose of this study was to describe an encapsulation method for cells using a membrane made of AN69, a copolymer of acrylonitrile which is considered as a reference in biocompatibility in the field of haemodialysis. The hydrogel of AN69 was obtained after a coagulation step at room temperature followed by a solvent/non-solvent (water) exchange phase. Microcapsules were obtained by co-extrusion of AN69 collodion and saline (with or without cells). The function of encapsulated cells was assessed in vitro, demonstrating cell survival after the microencapsulation procedure. These preliminary data are consistent with the potential interest for the development of the microencapsulation procedure aimed at realising a bioartificial pancreas.

Acrylic Resins↗
PubMed1994

NADPH-dependent lipid peroxidation capacity in unfixed tissue sections: characterization of the pro-oxidizing conditions and optimization of the histochemical detection.

Factors which influence the iron-stimulated lipid peroxidation in rat liver have been studied by incubating unfixed cryostat sections with a pro-oxidant system and using an optimized histochemical detection method for lipid peroxidation products with 3-hydroxy-2-naphthoic acid hydrazide and Fast Blue B. We used a method that was slightly different from the one described previously. The final reaction product was exclusively localized in the cytoplasm of liver parenchymal cells with a homogeneous distribution within the liver lobule. The absorbance maximum, as measured cytophotometrically, was found to be 550 nm. Maximum lipid peroxidation was observed when the pro-oxidant system contained 0.2 mM NADPH, 1 mM ADP and 15 microM FeCl2. Some reaction product was found when NADPH was omitted. Iron concentrations higher than 180 microM prevented the formation of lipid peroxidation products in certain areas of the sections, whereas ADP concentrations higher than 1 mM inhibited the reaction in the whole section. A pH dependency was also observed, with the highest lipid peroxidation at pH 7.2. Optimum lipid peroxidation was induced by incubating for 30 min at 37 degrees C with the pro-oxidant system. A linear relationship was found between the thickness of the sections (up to 20 microns) and the amount of lipid peroxidation products. The addition of scavengers of O2-. (superoxide dismutase), hydrogen peroxide (catalase) and OH. (mannitol) to the first step medium did not affect the amount of final reaction product. These findings appear to confirm the hypothesis proposed for events occurring in isolated microsomes, leading to the formation of hydroperoxides and ultimately lipid peroxidation-derived carbonyls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗
PubMed1994

Mutational analysis of HPV-18 E6 identifies domains required for p53 degradation in vitro, abolition of p53 transactivation in vivo and immortalisation of primary BMK cells.

The two major transforming proteins of oncogenic human papillomaviruses are encoded by the E6 and E7 oncogenes. Both viral proteins interact specifically with the products of cellular human tumour suppressor genes; E6 with p53 and E7 with Rb. However, the mechanism of action of E6 is still poorly understood in comparison with that of E7. Although extensive in vitro studies have been done with mutant E6 proteins, very little is known about the activities of E6 in vivo. In this study we have analysed the structure-function relationships of HPV-18 E6 in in vitro analyses and we correlate this with in vivo activity. These studies define a number of domains on the E6 molecule which are involved in the ability of E6 to target p53 for degradation in vitro. This analysis demonstrates that domains previously shown to be important in HPV-16 E6 (Crook et al., 1991; Mietz et al., 1992) are also conserved in HPV-18 and also reconciles the differences between these reports. A series of in vivo studies demonstrate that E6 mediated degradation of p53 in vitro is irrelevant both for cell transformation and for the ability of E6 to abolish p53 transcriptional activation. In addition, we show that at least four distinct regions of the E6 protein are involved in the p53 association in vivo.

3T3 Cells↗
PubMed1994

Common and rare genotypes of human apolipoprotein E determined by specific restriction profiles of polymerase chain reaction-amplified DNA.

The three common isoforms of human apolipoprotein E (apo E) differ at positions 112 and 158 and are named E3, E4, and E2 according to phenotyping by isoelectric focusing (IEF). The polymerase chain reaction (PCR) method allows the detection of common and several rare allelic apo E variants not detected by IEF. We propose a genotyping procedure for apo E that characterizes a given allele on the basis of amplification of specific sequences of the gene followed by the action of restriction endonucleases. When the nucleotide change does not lead to a restriction site, PCR-directed mutagenesis creates the discriminant site, and the differentiation of the three common alleles and five rare variants is possible. We present here profiles of common alleles and of three rare alleles, Weisgraber [Cys112/Asp127/Cys158], Christchurch [Cys112/Ser136/Arg158], and a new rare variant [Cys112/Leu142/Cys158].

Alleles↗
PubMed1993

[Central sleep apnea syndrome as a cause of impaired wakefulness in multiple myeloma].

Progressive day-time sleepiness developed in a 73-year-old man for 3 years known to have kappa-light-chain myeloma, treated with radio- and chemotherapy. His powers of concentration and intellectual performance were diminished. Neither clinical nor biochemically was there any indication of abnormal water and electrolyte metabolism or hyperviscosity syndrome. The neurological examination was unremarkable. His wife's observation of nocturnal breathing pauses suggested sleep-related abnormal breathing. Polysomnography showed severe central sleep apnoea: an apnoea index of 60/h and blood oxygen saturations as low as 78%. On biphasic positive airway pressure (BIPAP) ventilation by nasal mask at night the apnoea index fell to 6/h and the symptoms improved. During a break in treatment the day-time sleepiness again increased and regressed once again with BIPAP ventilation. There is a 1-5% prevalence of sleep-related impaired breathing among adults. This condition should thus be considered in the differential diagnosis of characteristic day-time sleepiness.

Aged↗