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Biomedical subjects

N K Sharma

Publications and source records attributed to N K Sharma.

At least 19 recordsLinked to original sources
PubMed2006

Presumed infectious endophthalmitis following cataract surgery in the UK: a case-control study of risk factors.

AIMS: To study risk factors for presumed infectious endophthalmitis complicating cataract surgery in the United Kingdom. METHODS: Two hundred and fourteen clinically diagnosed patients with presumed infectious endophthalmitis were compared with 445 control patients throughout the United Kingdom in a prospective case-control study. The cases were identified through the British Ophthalmological Surveillance Unit reporting card system. Control patients undergoing cataract surgery from 13 'control centres' throughout the United Kingdom were selected randomly. Risk factors were identified by univariate and multivariate logistic regression analyses. Pertinent variables relating to the cataract extraction procedure, antimicrobial prophylaxis, ophthalmic and medical history were analysed with regard to postoperative infection. RESULTS: Statistically significant risk factors in the multivariate model included inpatient cataract surgery (P=0.001), surgery in dedicated eye theatres (P<0.001), consultant grade surgeon (compared to registrar) (P=0.001), posterior capsule tear during cataract surgery (P=0.001). The use of face masks by the scrub nurse and surgeon during cataract surgery (P<0.001) and the administration of subconjunctival antibiotics at the end of surgery (P<0.001) were protective against postoperative infection. CONCLUSIONS: In order to minimise the risk of postoperative endophthalmitis we would recommend the wearing of face masks by the surgeon and scrub nurse during cataract surgery and subconjunctival antibiotics at the end of surgery.

Acute Disease↗
PubMed2006

Phosphate metabolism in the cyanobacterium Anabaena doliolum under salt stress.

In the present study, we have investigated the effects of NaCl concentrations on the growth and phosphate metabolism of an Anabaena doliolum strain isolated from a paddy field, in order to determine the possible effects of salinization. Growth rate, chlorophyll content, and protein content decreased with increasing salt concentration in the growth medium, while carbohydrate concentration increased. Phosphate content and phosphate uptake rate decreased. There was an increase in total alkaline phosphatase activity, with an approximately 7-fold increase in extracellular activity compensating for an approximately 3-fold decrease in cell-bound activity. NaCl effects on protein and chlorophyll concentrations were greater in P-deficient medium, while presence or absence of P in the medium had little effect on cellular carbohydrate concentrations. It is concluded that growth in high salt likely leads to reduced phosphate uptake in A. doliolum.

Adaptation, Physiological↗
PubMed2004

Transmission of gamma-ray-induced unstable chromosomal aberrations through successive mitotic divisions in human lymphocytes in vitro.

Transmission of unstable chromosomal aberrations through successive mitotic divisions M1-M4 was analysed in 3 Gy gamma-ray-irradiated G0 human lymphocytes in vitro, harvested at 50, 72 and 96 h. Bromodeoxyuridine (BrdU) incorporation and subsequently the fluorescence plus Giemsa (FPG) method allowed the cell cycle status of each cell scored to be ascertained. Higher dicentric frequencies were observed in cells within the same post-irradiation division derived from extended culture times, indicating either a delay in cell cycle progression of aberrant cells or different lymphocyte sub-populations. The yield of complete dicentrics decreased by a factor of two in passing from M1 to M2 and showed further reductions of 26 and 44%, respectively, in moving from M2 to M3 and from M3 to M4. In the case of conventionally stained metaphases, wherein the cell cycle status does not enter the picture, the dicentric frequencies showed a reduction in yield of 39.6% at 72 h and 52.1% at 96 h compared with 50 h, because the cells analysed comprise a mixture of metaphases in different cell cycles. In the FPG stained first division metaphases, 92-100% of dicentrics analysed at 50, 72 and 96 h and in the conventionally stained metaphases, 90-94, 72-84 and 54-80% of dicentrics analysed at 50, 72 and 96 h respectively were complete dicentrics (with fragments). In the M1, M2, M3 and M4 metaphases analysed, 92-100, 50-89, 20-70 and 10-50% of dicentrics, respectively, were complete dicentrics and 55-75, 53-68, 43-57 and 36-50% excess acentrics, respectively, were seen in cells with complete dicentrics. Interindividual variation was observed in cell cycle kinetics, radiation-induced chromosomal aberrations and micronucleus frequencies. A salient feature of the delayed effects was the induction of giant cells and the mirror dicentrics observed in them. The reduction in dicentric frequencies due to either cell cycle delay or cell death in successive generations is aided by the multiplicity of aberrations. Bridge-breakage-fusion (BBF) events mediated by dicentric chromosomes may also be instrumental in the perpetuation of chromosomal instability.

Adult↗
PubMed2003

Ascorbic acid potentiates mitomycin C-induced micronuclei and sister chromatid exchanges in human peripheral blood lymphocytes in vitro.

Vitamin C (l-ascorbic acid), an effective free radical scavenger present as ascorbate in most biological systems, is one of the most extensively studied antioxidant vitamins. Vitamin C acts as either a free radical scavenger or a pro-oxidant producing hydrogen peroxide and free radicals. The modulatory effect of L-ascorbic acid (AA) on Mitomycin C (MMC) induced chromosome damage has been evaluated in human peripheral blood lymphocytes in vitro. The effect of L-ascorbic acid, 200 microg/ml as 1- and 2-h pretreatment on the frequencies of the biomarkers micronuclei (MN), sister chromatid exchanges (SCEs), and chromosome aberrations (CA) induced by mitomycin C 0.1 and 0.2 microg/ml has been studied. AA pretreatment caused a statistically significant increase in MMC-induced MN and SCE frequencies for all treatment groups, but did not show an increase in induced chromosome aberrations compared to MMC treatment alone. Cell division delays caused by MMC was reversed in the presence of AA. Interindividual variability in MMC as well as AA plus MMC-induced MN, SCE, and CA frequencies were evident. Ascorbic acid potentiated MMC-induced chromosome damage in human lymphocytes in vitro. The potentiation observed has to be viewed in the light of metal ion catalysed autooxidation of AA in oxygenated media and the existence of an antioxidant system in vivo that inactivates oxyradicals before their interaction with DNA.

Adult↗
PubMed2002

Clinical performance of a compomer and amalgam for the interproximal restoration of primary molars: a 24-month evaluation.

OBJECTIVES: To evaluate the clinical performance of a compomer material (Dyract) in comparison with dental amalgam (Contour) for management of proximal caries in primary molars in young children. SETTING: General dental practice, and a dental hospital paediatric clinic. METHOD: This was a prospective study. A split mouth design was used with identical pairs of minimal Class II cavities, of matched tooth type in the same dental arch, usually diagnosed with the use of bitewing radiographs. Seventy-eight pairs of restorations were completed of which 60 pairs were available for evaluation after 24 months. RESULTS: Comparable retention rates were observed for both Dyract and amalgam. The retention rates were high for both materials, with only four amalgam and two Dyract restorations failing over 24 months. Significantly better marginal integrity (P < 0.05) was observed for Dyract compared with amalgam with no significant differences between the two materials for recurrent caries, wear or surface texture. CONCLUSIONS: Dyract seemed to be a suitable alternative to amalgam for proximal restorations in primary molars of young children for use in general dental practice.

Child↗
PubMed2002

Posterior fossa oligodendroglioma.

Oligodendroglioma are the tumors of glial cells. They are rare in children and are more common in the cerebral hemispheres. A rare case of infratentorial oligodendroglioma in a female child is being reported here.

Cerebellar Neoplasms↗
PubMed2002

Correlation between CT scan and automated perimetry in supratentorial tumors.

An attempt was made to correlate various types of visual field defects on automated perimetry with the findings of computed tomography in 44 patients of supratentorial tumors. All the patients above the age of 10 years were subjected to complete neurological examination including investigations like plain X-rays and CT scan, however, MRI and angiography were performed wherever indicated. Ocular examination particularly pertaining to neuro-ophthalmological profile was carried out with special emphasis on automated perimetry on Humphrey field analyser. The results indicated that automated perimetry was capable of reliably detecting and quantitating the visual field defects and thus established the location of the tumor in 72% patients when compared to CT scan. Hence, any patient with neuro-ophthalmic features should be subjected to automated perimetry for early diagnosis and probable location of intracranial space occupying lesion affecting visual pathways.

Adult↗
PubMed2001

Bedside ultrasound: a useful tool for the on-call urologist?

OBJECTIVE: To assess the accuracy and benefit of urgent bedside ultrasound scanning in urological emergencies by urology trainees. METHODS: In this prospective study, 111 patients (86 acute flank pain, 15 renal failure, 10 haematuria) referred as urological emergencies, were scanned for urinary tract abnormalities at the bedside, by a trainee urologist, over 18 months. The ultrasound findings were compared with the results of imaging performed by a consultant radiologist and its influence on clinical management analysed. RESULTS: Bedside ultrasound proved life saving in 5 patients (2 pyonephrosis, 2 leaking aneurysms, one bilateral ureteric injury). It significantly influenced management in 11 patients, excluded obstruction in the presence of infection.in 13 patients, helped in early diagnosis in 32 patients and ruled out gross urological pathology in 28 patients. It was misleading in 22 patients, mainly with ureteric colic (where the timing of the test can affect the findings), though the outcome was not adversely affected in any. Bedside ultrasound was reasonably accurate (sensitivity 81% and specificity 92%). CONCLUSIONS: Bedside ultrasound is a useful tool to help the decision-making in urological emergencies and reasonably accurate in hands of a trainee urologist. It is especially helpful for excluding obstruction in presence of infection or renal failure. However it has inherent limitations in assessing acute ureteric colic.

Acute Disease↗
PubMed2001

Pseudoaneurysms of the femoral artery: recommendation for a method of repair.

PURPOSE: Formation of an anastomotic aneurysm in the femoral artery is one of the major complications after femoral artery surgery. The aim of this study was to assess the method of repair of femoral anastomotic aneurysms and their outcome in a District General Hospital. METHODS: A retrospective consecutive cohort of anastomotic femoral aneurysms, operated between 1977 and 1998, were studied. RESULTS: Twelve patients with a total of 19 pseudoaneurysms were treated. Five of the aneurysms were repaired using a vein patch and two had re-suturing of the anastomosis. Twelve aneurysms were repaired with complete revision of the anastomoses using interposition grafts. There were no recurrences in the interposition graft group whilst two recurred in the seven aneurysms repaired using re-suturing/vein patch. CONCLUSION: Interposition grafting would appear to be the method of choice for repair of femoral pseudoaneurysms as the outcome was better than that with re-suturing or using a patch closure technique.

Aged↗
PubMed2000

Development of a single-reaction multiplex PCR toxin typing assay for Staphylococcus aureus strains.

We describe here the development of a single-reaction multiplex PCR assay for the enterotoxin genes from Staphylococcus aureus that utilizes a universal toxin gene primer in combination with toxin-specific primers to amplify characteristic toxin gene products. In combination with a new DNA purification method, the assay can detect enterotoxin genes A to E from a pure culture within 3 to 4 h. The test was used to characterize a diverse set of environmental S. aureus isolates, and a 99% correlation with toxin typing using standard immunological tests was found. The design of the assay allows it to be extended to include both newly characterized and as-yet-unknown toxin genes.

Animals↗
PubMed2000

Need for bringing in a change in biochemistry curriculum to make it clinically oriented?

OBJECTIVES: This study was conducted to (a) assess the views of medical students and doctors regarding relevance of biochemistry training, (b) explore if they have any suggestion to bring in any improvement in contents of biochemistry curriculum and mode of teaching. METHODS: In 1997-98, a structured questionnaire was filled up by 114 medical students and 118 doctors. RESULTS: As many as 62/114 (55%) medical students and 40/118 (34%) doctors believed that it is not important to remember minute details of biochemical reactions (p value < 0.0001). Among medical students, 108/110 (98.2%) agree that a clinician should be invited to seminars for developing skills of interpretation of laboratory investigations; whilst 110/118 (93.2%) doctors expressed similar view, p value ns. Approximately 92% responders favored that departments biochemistry and physiology should co-ordinate on the topics of common interest in order to save time and effort. What is the most informative and effective way of teaching biochemistry?' in response to this question only 0.9% responders opted lecture as the best option. Seminars with active participation of medical students was preferred by 93.2% responders. About 6.9% responders reckoned that symposium prepared by a more than one teacher. In response to the question whether it is possible to cover pre-clinical subjects in 12 months so as to allow spiral mode of curriculum, 73% of all the responders agreed that it would be good idea, there was no difference of opinion among the doctors and medical students. On the other hand, 27% were strongly opposed to this suggestion. CONCLUSIONS: We suggest that there is a need to modify the contents, methods of teaching, and curriculum organization of training in clinical biochemistry. How best the curriculum can be made problem oriented needs to be debated among medical educationists.

Biochemistry↗