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Biomedical subjects

S Mitra

Publications and source records attributed to S Mitra.

426 records · Page 24Linked to original sources
PubMedDate not supplied

Spatial expression of a DNA repair gene, N-methylpurine-DNA glycosylase (MPG) during development in mice.

BACKGROUND: DNA repair is a crucial phenomenon that maintains the chromosome integrity of genome which are continuously damaged by endogenous and exogenous alkylating agents. If the damaged DNA is not repaired, it may lead to mutation, chromosomal aberration, aging and cancer. N-methylpurine-DNA glycosylase (MPG), a ubiquitous DNA repair enzyme, removes N-methylpurine and other damaged purines in DNA. MATERIALS AND METHODS: MPG mRNA expression was revealed at various stages of mouse development from day 7.5 p.c. (post coitum) embryo to day 400 mature adult by Northern blot hybridization or RT-PCR. RESULTS: MPG transcripts were abundant in the mouse embryo during pregnancy and in adult testis and ovary. The MPG mRNA level in the testis was low in 1-week-old mice, but the level showed its maximum among the organs tested in 4-week-old young adults. In placenta, the level of MPG mRNA continuously decreased from day 7.5 p.c. to day 17.5 p.c. CONCLUSIONS: The spatial expression of MPG gene is highly regulated. Transcription of MPG is maximum in rapidly dividing and growing tissues during development. These data suggest that an elevated rate of MPG transcription is required for DNA replication.

Animals↗
PubMedDate not supplied

Hydrodissection of conjunctival flap during trabeculectomy in eyes with conjunctival scarring caused by trachoma.

BACKGROUND AND OBJECTIVE: Conjunctival scarring caused by trachoma represents a substantial challenge even to the most experienced cataract/glaucoma surgeon. We describe a simple technique of hydrodissection of conjunctival flap during combined trabeculectomy and phacoemulsification in eyes with conjunctival scarring caused by trachoma, and discuss its impact on surgical outcome. PATIENTS AND METHODS: A prospective study was conducted in 10 Omani patients, aged 48 to 83 who underwent combined trabeculectomy and phacoemulsification with intraocular lens (IOL) implantation. The conjunctival flap was prepared after hydrodissection using a mixture of 1 mL of balanced salt solution (BSS) and 1 mL of lignocaine 2% with 1:200,000 adrenaline. Outcome measures that were evaluated were visual function, intraocular pressure (IOP) and bleb characteristics. Patients were followed-up postoperatively for a minimum period of 6 months. RESULTS: The mean age of patients was 60.4 years (48-83) and a functioning bleb after 6 months was seen in 8 (80%) cases. IOP < 20 mm of Hg (applanation tonometry) without antiglaucoma medications was found in 8 cases; 1 case required one antiglaucoma medication and 1 case required more than one antiglaucoma medication for control of IOP. The latter was reoperated for control of IOP. Nonprogression of visual field was found in 8 (80%) cases. CONCLUSION: Preparation of conjunctival flap by hydrodissection was found to be a simple modification of the conventional technique during combined trabeculectomy and phacoemulsification in trachomatous eyes. It reduced conjunctival dissection, use of cautery and possibility of button-holing of the conjunctiva during dissection in scarred eyes. The minimal tissue dissection involved in this procedure reduced wound healing and thereby increased chances of a functioning bleb, control of IOP and nonprogression of visual field compared to combined surgery employing a conventional method (nonhydrodissection method) of conjunctival flap dissection.

Aged↗
PubMedDate not supplied

Migration and stability.

"In this endeavor to incorporate net migration in a model of population growth, we have found that when net maternity rates are held constant, birth trajectories can be traced in several examples. We have basically experimented with (a) unchanging age-specific net migration rates and also with (b) constant number of net migrants with unchanging age composition. In most cases, the birth trajectory approaches an exponential pattern of growth with two interesting exceptions. When the intrinsic rate of growth is negative, the population approaches stationarity in the second example. Also a linear trend is found in the same example, when the net reproduction rate is equal to one." (SUMMARY IN FRE AND ITA)

Age Distribution↗
PubMedDate not supplied

On the characteristics of the parameters of a life table function.

This study is based on a mathematical model for the life table survivorship function developed by the author, "the form of which has been logically arrived at in a manner such that the simple but the well known constraints of the life table functions can be met by the model. There are basically three parameters in the model which can be estimated by the method of least squares after the variables are subjected to appropriate transformations. The characteristics of these parameters have been investigated in this paper which [makes] it readily apparent that the model can provide good approximations to a wide variety of life tables." (summary in FRE, ITA)

Demography↗
PubMedDate not supplied

Cardiac tumours: an observational study.

We studied 38 patients with cardiac tumours. Of these, 30 had primary cardiac tumours while the rest had secondary tumours. The commonest manifestations in patients with primary tumours were exertional breathlessness (23), fever (9), mitral diastolic murmur (15), loud pulmonary component of the second heart sound (16), and mitral systolic murmur (21). Left atrial myxoma was the commonest diagnosis (24) followed by left ventricular leiomyoma (2), right atrial myxoma (2, one with RA and RV both), RV myxoma (1), and left ventricular haemangioma (1). The commonest modes of presentation of secondary cardiac tumours were atrial extrasystoles (5) and pericardial friction rub (4). Histopathological reports revealed bronchogenic carcinoma (4), breast carcinoma (2), seminoma of the testis (1) and lymphoma (1). The unexpectedly low number of secondary cardiac tumours in this series is attributed to the lack of routine autopsy studies in our institute.

Adolescent↗
PubMedDate not supplied

Reuse of pacemaker.

Implantation of a permanent pacemaker is an expensive proposition for the poor patients of our country. Many patients on permanent pacemaker die prematurely due to diseases or conditions not related to pacemaker function. The purpose of this study was to reuse these pacemakers after thorough cleansing and proper sterilisation in other suitable patients and compare the efficiency of the reused pacemakers with that of newly implanted ones. Between April 1979 and April 1992, 642 patients implanted with reused pacemakers were studied. The study population consisted of patients ranging in age from 15-85 years and included patients of both sexes (M:F = 4:1). The mean period of follow-up was 7.5 +/- 5.6 years. Removal and reimplantation of the pulse generators was carried out after obtaining the State Government's approval, informed consent of the donors, relatives and recipients. The functional status of the pulse generators was tested by a "pacing system analyser". The clinical indications for reuse were chronic complete heart block, symptomatic bifascicular heart block, sick sinus syndrome and chronic complete heart block with congestive heart failure, in decreasing order of frequency. In terms of morbidity and mortality, the efficacy of reused pacemakers was highly comparable with that of newly implanted ones. The infection rate in cases of reuse from dead patients was comparable to that in cases of new implantation. However, pacemakers reused in the same patient showed a high rate of infection. With the aid of newer generations of antimicrobials, infection when matched with efficacy and economy (of reuse) does not seem to be a major factor against pacemaker reuse.

Adolescent↗
PubMedDate not supplied

Aortoarteritis involving supra-aortic trunks: a profile of six cases.

Six patients (2 male, 4 female; age range 24 to 36 years) with aortoarteritis involving the supra-aortic trunks were investigated and surgically managed by bypass graft with either preclotted dacron or polytetrafluoroethylene (PTFE) in an urban institute. There has been no mortality and post-operative functional recovery has been satisfactory in all the cases.

Adult↗