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Biomedical subjects

A Mathew

Publications and source records attributed to A Mathew.

At least 91 records · Page 5Linked to original sources
PubMed1975

The use of analytical isoelectric focusing for detection and identification of beta-lactamases.

BETA-Lactamases (EC. 3.5.2.6) from strains of Gram-negative bacteria have been studied using analytical isoelectric focusing. This permits a visual comparison of the patterns of beta-lactamase bands produced by enzymes from different organisms. Purification of crude intracellular preparations is unnecessary and the technique is sufficiently sensitive to demonstrate beta-lactamase in mutants previously reported to lack the enzyme. R that have not been distinguished from one another biochemically or immunologically can be differentiated by isoelectric focusing. Conversely, the enzymes specified by the R factors RTEM, R1 and RGN14, with identical isoelectric focusing patterns have the same biochemical properties. Chromosomal and R-factor-mediated beta-lactamases from single strains have been separated and their identities confirmed by immunoisoelectric focusing. R factor-mediated enzymes gave identical isoelectric focusing patterns irrespective of the host strain. Isoelectric focusing can therefore be used to observe the transfer of beta-lactamases carried by R factors.

Amidohydrolases↗
PubMedDate not supplied

Cryptophthalmos.

Cryptophthalmos, a very rare congenital anomaly of the eye, is characterised by skin passing continuously from the forehead to the cheek over a malformed eye. It may be isolated or more commonly as a part of Fraser syndrome. Cryptophthalmos is classified into three types: complete, incomplete and abortive. Surgical reconstruction is the modality of treatment available. We present a case of bilateral, complete, isolated cryptophthalmos, who has undergone stage 1 of reconstructive surgery.

Eye Abnormalities↗
PubMedDate not supplied

In vitro activity of ampicillin/sulbactam against enterococci determined by the time-kill method.

Time-kill studies demonstrated that at clinically achievable serum concentrations, ampicillin/sulbactam was equivalent in activity to ampicillin alone against non-beta-lactamase producing isolates of Enterococcus faecalis and Enterococcus faecium. Sulbactam possessed no antibacterial activity against these organisms. It is not yet known if the activity of ampicillin will be increased with the addition of sulbactam when tested against beta-lactamase-producing enterococci.

Ampicillin↗
PubMedDate not supplied

Squamous cell carcinoma of the tongue among young Indian adults.

Oral cancer is one of the commonest cancers among males in India. This study was carried out to evaluate the demographics, risk profile, clinicopathologic features, and treatment outcome in young patients with squamous cell carcinoma (SCC) of the tongue. Patients under the age of 35 years with SCC of the tongue presenting between 1982 and 1996 were identified using institutions centralized electronic database. Demographic, clinical, and pathologic characteristics were abstracted from the case records. Survival was calculated by Kaplan-Meier method. One hundred and fifteen patients with histologically confirmed SCC of the tongue were analyzed. The mean age at presentation was 30.5 years with a 1.7:1 male to female ratio. Prior exposure to tobacco and alcohol was noted in 58 (50.5%) patients. At presentation, 70 (60.9%) were in stages III and IV, and 59 (51.3%) patients had regional lymph node involvement. The overall disease-free survival (DFS) at 3 and 5 years were 63% and 54.9%, respectively. A statistically significant difference in DFS was seen between patients with N(0) and N(1) disease compared to N(2) or N(3) disease. Various other factors like age, sex, habits, and stage of the disease were found to have no significant effect on DFS. Results of the present study suggest that contrary to the belief, the survival among young patients is almost similar to that in older patients.

Adult↗
PubMedDate not supplied

Malignant phyllodes tumor.

The study aims to evaluate the survival and prognosis of patients with malignant phyllodes tumor. Between 1982 and 1998, 37 women with malignant phyllodes tumor were treated at the Regional Cancer Center, Trivandrum. Twelve patients were recurrent. Survival was estimated using the Kaplan-Meier method. Patient, disease, and treatment factors were compared using log-rank test. The Cox-proportional hazard model was employed to identify the prognostic factors. Thirty-six patients had surgery. Twenty-five patients received postoperative radiotherapy, and 2 received chemotherapy in addition. The median follow-up was 43 months (range 1-170 months). Eight patients failed locally, and 7 of these were successfully salvaged by surgery. The 5-year overall survival was 74.2% (95% CI, 0.44 to 0.89), whereas 5-year disease-free survival was 59.6% (95% CI, 0.39 to 0.7). The margin of surgical excision was found to be the only independent prognostic factor (p=0.003). However, patients with tumor size more than 5 cm (hazard ratio 2.9) were found to have increased hazard, whereas those receiving adjuvant radiotherapy (hazard ratio 0.6), married women (hazard ratio 0.4), and those women over the age of 35 years (hazard ratio 0.7) showed a decreased hazards. Cystosarcoma phyllodes is a rare malignancy of the female breast. Surgery with adequate margins is the primary treatment. Adjuvant radiotherapy appears to improve the disease-free survival.

Adult↗
PubMedDate not supplied

Nucleosides and glutamine are primary energy substrates for embryonic and adult chicken red cells.

It has been assumed that glucose is a major energy yielding substrate for chicken red blood cells. In this report we show that glucose fails to maintain cellular ATP levels in embryonic and mature chicken erythrocytes during overnight incubation. Of over a dozen metabolites tested, inosine, guanosine, and glutamine were the most efficacious ATP-sustaining substrates. Of seven potential citric acid cycle substrates, only glutamine significantly sustained ATP levels. Incubation with inosine plus glutamine sustained the ATP level at over 70% of the initial value found in embryonic chicken red cells. Uridine, cytidine, xanthosine, glutamate, and pyruvate were ineffective substrates. Similar results were obtained with adult erythrocytes, except that glutamine plus inosine fully sustained ATP levels during long-term incubation. Adenosine did not sustain ATP levels. Below 1 mM, the adenosine level was rapidly exhausted and above 1 mM its presence led to cell lysis. The ability of some nucleosides to maintain ATP levels is consistent with the high numbers of nitrobenzylthioinosine binding sites (nucleoside transporter sites) both in mature chicken red cells (approximately 10,000 sites/cell) and in embryonic red cells (approximately 30,000 sites/cell). Unlike pig red cells which switch from glucose to nucleosides at the erythrocyte stage, chicken cells show primary dependence on nucleoside metabolism at the embryonic stage.

Adenosine↗
PubMedDate not supplied

Prognostic significance of CEA and CA 19-9 in colorectal cancer in Kuwait.

Preoperative CEA and CA 19-9 levels have been used in the past as prognostic indicators in colorectal cancer, but Dukes' stage is still considered to be the most important prognostic factor. Recent survival estimates may have been influenced by the fact that in the last decade adjuvant chemotherapy and postoperative irradiation have been included in the routine management of advanced-stage disease. In a heterogeneous Kuwaiti population higher reference levels (95th percentile) of CEA and CA 19-9 have been found than those usually employed. In the present study 62 patients with Dukes' stage B + C could be analyzed for two-year disease-free survival (DFS). Relapse was observed in 19 patients, 28 patients were disease free and 15 patients with censored observations were included. No significant difference in DFS was observed in Dukes' B (69%) versus Dukes' C (48%) patients (p = 0.09). On the other hand, Dukes' stage B + C patients with elevated preoperative levels of CEA or CA 19-9 had a significantly poorer DFS than patients with normal levels. For CEA levels below or above the cutoff the DFS was 74% versus 23% (p = 0.003); for CA 19-9 levels below or above the cutoff the DFS was 71% versus 33% (p = 0.004). In 54 patients with Dukes' stage B + C for whom preoperative levels of both CEA and CA 19-9 were available multivariate analysis revealed a decreasing risk of relapse in the following order: CEA and/or CA 19-9 elevated (chi-square 7.09; p = 0.008), CA 19-9 elevated (chi-square 6.27; p = 0.01), CEA elevated (chi-square 5.47; p = 0.02), and Dukes' C (chi-square 2.08; p = 0.15 n.s.). Hence, novel treatment protocols may have improved the disease-free survival, but the use of adjuvant chemotherapy and/or radiotherapy is of questionable benefit in patients who have elevated levels of CEA and/or CA 19-9 prior to treatment.

Biomarkers, Tumor↗
PubMedDate not supplied

Malignant tumours of the minor salivary glands: a survival analysis of 17 years from a tertiary referral cancer centre.

BACKGROUND: Malignant tumours of the minor salivary glands are rare and constitute less than 0.5% of all malignant neoplasms. AIM: This study was carried out to evaluate the clinical presentation, site distribution, treatment, survival and predictors of survival in malignant minor salivary gland tumours. SETTING: A tertiary care, superspeciality referral hospital. DESIGN: Retrospective analysis. PATIENTS AND METHOD: Forty-two cases of minor salivary gland tumours treated over a period of 17 years were reviewed for clinical presentation, histopathology, stage distribution, treatment and treatment outcome. STATISTICAL ANALYSIS: Survival by Kaplan Meier Method and the outcomes were compared using log-rank test. RESULTS: The mean age of the patients was 46.9 years with a male to female ratio of 1.4:1. Majority of the patients presented with a painless progressive swelling, with 13 (31%) of them in T2 stage. About one-third of the patients had palpable lymph nodes at presentation, while none had distant metastasis. Palate was the commonest site and mucoepidermoid carcinoma was the commonest hispathological type. About 1/3 of the patients were treated with primary surgery and were followed up by adjuvant radiotherapy. Seven patients underwent palliative treatment alone. Over a mean follow-up of 30 months, 5 patients failed. The disease free survival was 72% at 5-year, none of the factors studied were found to significantly influence survival. CONCLUSIONS: Results of the present study suggest that minor salivary gland tumours should be treated with primary surgery irrespective of site and histological type to achieve best loco-regional control and survival.

Adolescent↗
PubMedDate not supplied

Reference levels of the tumor markers carcinoembryonic antigen, the carbohydrate antigens 19-9 and 72-4, and cytokeratin fragment 19 using the Elecsys Relecsys 1010 analyzer in a normal population in Kuwait. The importance of the determination of local reference levels.

The tumor markers CEA, CA 19-9, CA 72-4 and CYFRA 21-1 were analyzed in a group of apparently healthy subjects (n=232) in Kuwait using the Elecsys Relecsys 1010 analyzer. The distribution of the tumour marker levels was analyzed separately in Kuwaitis (n=103), non-Kuwaitis (n=129), smokers (n=68), non-smokers (n=164), males (n=138) and females (n=94). The distribution of CEA was significantly different in Kuwaitis vs. non-Kuwaitis in the total population (p=0.033) and in non-smokers (p=0.049); in males vs. females in the total population (p<0.0001) and in non-smokers (p=0.0002); and in smokers vs. non-smokers in the total population (p<0.0001) using the non-parametric Mann-Whitney U test. None of the other tumour markers showed significant differences in the subgroups. The upper reference level was defined as the 95th percentile of the normal values in each group. A higher reference level of CEA was observed in smokers (vs. non-smokers) in the total population. Also higher reference levels of CEA were observed in males (vs. females) both in the total population and in non-smokers. In the total population the respective reference levels were: CEA: 4.4 microg/L, CA 19-9: 35 kU/L, CA 72.4: 2.4 kU/L, and CYFRA 21.1: 2.1 microg/L. These results were compared with data in the kit inserts and literature data. The impact of 95th percentiles in a local heterogeneous population is discussed.

Adult↗
PubMedDate not supplied

A step towards quality medical research.

Only well planned and conducted research can answer questions that arise in day-to-day clinical practice. Unfortunately, most studies in India are deficient in design or execution. The results thus obtained are biased and cannot be extrapolated to the population studied. Some important questions which arise during the statistical design of investigations are selection of subjects on which observations are to be made, number of observations falling into different groups, allocation of subjects among different groups, etc. Besides planning and execution, appropriate methods need to be chosen for data analysis beforehand. If the study has been well designed and correctly analysed, the interpretation of results can be fairly simple. The present communication focuses on some issues relating to the planning of investigations in medical research with emphasis on statistical design.

Research Design↗
PubMedDate not supplied

A profile of tumor markers in the population of Kuwait.

The tumour markers CEA, AFP, CA 125 and CA 199 were analyzed in a group of apparently healthy subjects in Kuwait. The sample (n = 394) included both genders in the population with a mean age of 38 (S.d. 12.0) years. The distribution of CEA levels values was significant different (Mann-Whitney U test) between Kuwaiti and non-Kuwaiti. The distribution of AFP levels was found to be the same in all groups. The distribution of CA 125 levels was significantly higher in females than in males, both in Kuwaiti and non-Kuwaiti. The distribution of CA 19-9 values was found to be significantly higher in the Kuwaiti female group when compared to the males. The upper reference level was defined as the 95 percentile of the normal values in each group. In the total population the reference level of AFP was 5.6 micrograms/l and of CA 19.9 43 kU/l. The reference level of CA 125 was 16 U/l in males and 24 kU/l in females, respectively. The CEA reference level in Kuwaitis was 6.9 micrograms/l and in non-Kuwaitis 4.4 micrograms/l. The results indicated the importance of determining the reference levels of tumour markers for each individual laboratory. It was also emphasized that care should be taken on the impact of 95 percentiles of normal and benign disease groups.

Adult↗
PubMedDate not supplied

Estimating cancer survival in developing countries. Use of reply-paid post cards to augment follow-up information.

Survival from cancer is one of the indices to evaluate cancer control activities. Reliability of survival estimates depends to a large extent on the completeness of follow-up information available for patients in the study group. Loss to follow-up (LFU) is one of the potential problems introduced in follow-up of cancer patients. An attempt is made to improve the follow-up system for reducing the LFU of cancer patients by repeatedly sending reply-paid post cards for the LFU patients. A total of 353 ovarian cancer patients registered at the Regional Cancer Centre, Trivandrum during a three year period and followed-up to a total of five years showed 67 percent loss to follow-up. The five-year survival rate of this group calculated using Kaplan-Meier method under the assumption that the LFU's occurred at random was 75 percent. Efforts to improve the follow-up rate for the study population were made through the simple and cost effective method of postal enquiry which resulted in a reduction of 63 percent of losses to follow-up. Incorporation of this information in the data brought about a revised five-year survival estimate of 55 percent. The reply paid post card system was found to be effective in obtaining useful follow-up data. The result shows that LFU can be reduced by better design of survival study.

Cohort Studies↗