Biomedical subjects

B Mathew

Publications and source records attributed to B Mathew.

At least 55 records · Page 3Linked to original sources

PubMed1995

Evaluation of mouth self-examination in the control of oral cancer.

This study was planned to evaluate the feasibility of mouth self-examination (MSE). Some 450 college students distributed to 9000 households a brochure describing the risk factors of oral cancer, the appearance of premalignant and malignant lesions of the oral cavity and the methods of MSE with pictures. All subjects with tobacco habits and/or aged 30 years or over were asked to read the brochure carefully and to report to the clinic conducted in their locality on fixed days, if they suspected an abnormality while practising MSE. Out of the approximately 22,000 eligible subjects, 8028 (36%) practised MSE. Among the 247 subjects reporting to the clinics seven (3%) had oral cancer and 85 (34%) had oral precancerous lesions; the others had either benign lesions or normal anatomical variations. Six of the seven subjects with oral cancer had stage I disease, five of whom accepted treatment and were alive disease-free 5 years later. The detection rates of oral cancer compared favourably with the previously reported detection rates using trained health workers. Although this study demonstrated that MSE is feasible, larger studies are required to evaluate whether health education could result in a sustained practice of MSE resulting in reduction in incidence of and mortality from oral cancer.

Adult↗

PubMed1995

Evaluation of chemoprevention of oral cancer with Spirulina fusiformis.

The blue-green microalgae Spirulina, used in daily diets of natives in Africa and America, have been found to be a rich natural source of proteins, carotenoids, and other micronutrients. Experimental studies in animal models have demonstrated an inhibitory effect of Spirulina algae on oral carcinogenesis. Studies among preschool children in India have demonstrated Spirulina fusiformis (SF) to be an effective source of dietary vitamin A. We evaluated the chemopreventive activity of SF (1 g/day for 12 mos) in reversing oral leukoplakia in pan tobacco chewers in Kerala, India. Complete regression of lesions was observed in 20 of 44 (45%) evaluable subjects supplemented with SF, as opposed to 3 of 43 (7%) in the placebo arm (p < 0.0001). When stratified by type of leukoplakia, the response was more pronounced in homogeneous lesions: complete regression was seen in 16 of 28 (57%) subjects with homogeneous leukoplakia, 2 of 8 with erythroplakia, 2 of 4 with verrucous leukoplakia, and 0 of 4 with ulcerated and nodular lesions. Within one year of discontinuing supplements, 9 of 20 (45%) complete responders with SF developed recurrent lesions. Supplementation with SF did not result in increased serum concentration of retinol or beta-carotene, nor was it associated with toxicity. This is the first human study evaluating the chemopreventive potential of SF. More studies in different settings and different populations are needed for further evaluation.

Adult↗

PubMed1994

Argyrophilic nucleolar organizer regions in the evaluation of tumour progression in the oral mucosa: correlation with tissue pathology.

The present study has analysed the numbers of argyrophilic nucleolar organizer regions (AgNOR) in normal tissues and in premalignant and malignant lesions of the oral mucosa in order to assess their potential as a biological marker for tumour progression. On comparison of AgNOR numbers in different lesions, carcinomas showed the highest number (4.65 +/- 0.98) compared to leukoplakias (2.38 +/- 0.47) and normal tissues (1.53 +/- 0.39). Spindle cell carcinomas and poorly differentiated squamous cell carcinomas had higher AgNOR counts than well-differentiated carcinomas. In various clinically different types of oral leukoplakia, the lowest AgNOR counts were observed in homogenous leukoplakia and the highest in speckled leukoplakia. No significant difference in AgNOR number was observed between non-dysplastic and dysplastic leukoplakia, although a significant difference was evident between dysplastic leukoplakia and normal oral mucosa. Correlating the AgNOR count and tumour progression, a significantly high positive correlation coefficient (r = 0.7969, P = 0.0000) was observed.

Humans↗

PubMed1994

Scanning electron microscopy of different types of oral leukoplakia: comparison with normal and malignant oral mucosa.

The present study analysed surface architecture of normal, premalignant and malignant oral mucosa using scanning electron microscopy to evaluate its role in early diagnosis of potentially malignant oral lesions. The surface ultrastructure of the buccal mucosa in tobacco chewers showed variations from that of non-chewers. Homogenous leukoplakia demonstrated well-defined intercellular junctions and the microrugal surface pattern as seen in normal mucosa. In verrucous leukoplakia, the surface layer consisted of characteristically-shrunken desquamated hyperkeratotic cells. Erosive leukoplakia had a discontinuous superficial layer along with complete loss of intercellular ridges. Speckled leukoplakia also showed marked abnormalities such as thickened irregular protrusions and evidence of a villus-like pattern. These villus-like structures were comparatively prominent in leukoplakia showing dysplasia. Oral carcinoma showed marked altered surface ultrastructure and had a pattern similar to dysplastic lesions. The irregular swollen elongated protrusions with villous-like structures that were observed in carcinoma and dysplastic lesions can, therefore, be considered as surface markers for potentially malignant leukoplakia.

Carcinoma, Squamous Cell↗

PubMed1994

Alterations in expression of basement membrane proteins during tumour progression in oral mucosa.

Expression of three basement membrane proteins--collagen IV, laminin and fibronectin--was studied in normal, hyperplastic, dysplastic and neoplastic conditions of the oral mucosa using immunohistochemistry. Collagen IV and laminin exhibited similar staining patterns, while fibronectin showed a different pattern of expression. The expression of collagen IV and laminin also demonstrated an inverse correlation between staining intensity, thickness and basement membrane continuity in various stages of tumour progression. In contrast to the continuous and intense staining of basement membrane in normal oral mucosa with collagen IV and laminin antibodies, severe dysplasia and carcinoma exhibited discontinuous, thin and weakly stained basement membrane. The expression of fibronectin showed a direct correlation with extent of tumour progression. In normal mucosa, expression of fibronectin was almost absent, whereas in carcinoma intense expression of fibronectin was evident in the basement membrane and basal cells. These results emphasize the value of basement membrane proteins as biological markers for assessing oral carcinogenesis.

Antibodies, Monoclonal↗

PubMed1994

Alterations in expression of terminal differentiation markers of keratinocytes during oral carcinogenesis.

Expression of cytoskeletal proteins has been shown to be dependent on the differentiation status of the tissue. In the present study, expression of two cytoskeletal proteins normally present in terminally differentiated keratinocytes, namely cytokeratin types 10/11 and involucrin, were studied in different stages of tumour progression in the oral mucosa. Results showed that cytokeratins 10/11 and involucrin strongly correlated with the differentiation status of cells. High expression was observed in non-dysplastic hyperplastic epithelium as compared to normal, dysplastic and neoplastic epithelium. In addition, various grades of dysplasia showed an inverse correlation with expression of these proteins. Statistical analysis of the results also showed a negative correlation between the differentiation of upper spinal cells and the stage of tumour progression. It therefore appears that the proteins studied may be useful as markers for epithelial carcinogenesis.

Biomarkers, Tumor↗

PubMed1994

Co-expression of ras p21 and epidermal growth factor receptor during various stages of tumour progression in oral mucosa.

Ras p21 and epidermal growth factor receptor (EGFR) have commonly been implicated in a variety of malignancies. The present study immunohistochemically analysed the relationship between the expression of ras p21 and EGFR in normal, premalignant and malignant lesions of the oral mucosa. Except for normal mucosa, all other lesions showed a more or less similar expression pattern of both ras p21 and EGFR. It was also observed that the expression of both proteins was mostly confined to the basal or basaloid cells of the leucoplakia and carcinoma lesions, respectively. Normal keratinizing type mucosa showed expression of ras p21 and EGFR in the basal and lower spinal cells. However, in non-keratinizing mucosa the expression of ras p21 was totally negative while EGFR was restricted to the basal cells. Statistical analysis revealed a good correlation between the expression of ras p21 and EGFR with the various histological stages of tumour progression. The presence of these proteins in immature dividing cells of premalignant and malignant lesions thus emphasizes their relationship with cell proliferation.

ErbB Receptors↗

PubMed1994

Differential expression of cytokeratin proteins during tumour progression in oral mucosa.

The expression pattern of cytokeratin filaments in epithelia has been shown to be dependent on their type and grade of differentiation. The type of expression of cytokeratin in a cell may also be altered during carcinogenesis or other pathological conditions. The present study examined the alterations in expression of various cytokeratin types during different stages of tumour progression in the oral mucosa. Six monoclonal anti-cytokeratin antibodies were used for the study. Conspicuous staining differences with these antibodies were evident between normal keratinizing and non-keratinizing mucosa. These differences can be correlated to the differentiation pattern of the normal mucosa types. Antibodies specific to cytokeratin types 10/11, 19 and 14 showed significant correlation with stage of tumour progression. In addition cytokeratin type 18 also showed prominent differences in expression between different stages of tumour progression. These alterations in cytokeratin expression suggest that the terminal differentiation pathway of keratinocytes is disturbed during oral carcinogenesis. The results of the present study also emphasize the potential of using cytokeratin filaments as markers in the biological staging of oral premalignant and malignant lesions.

Antibodies, Monoclonal↗

PubMed1993

Expression of lectin-specific cellular glycoconjugates during oral carcinogenesis.

The binding pattern of two lectins, concanavalin A (ConA) and peanut agglutin (PNA), in various phases of tumour progression in the oral epithelium was studied. These included non-dysplastic, dysplastic and neoplastic lesions as well as normal tissue. ConA and PNA showed intense staining in the basement membrane of all types of lesions. Little difference was observed in the staining patterns between different stages of oral carcinogenesis, either with ConA or PNA. ConA showed mild cytoplasmic and membrane staining in all types of lesions while PNA showed moderate to intense staining in both the cytoplasm and membrane of lower-layer cells in all histological groups. The present study therefore shows that these lectins have limited value in the elucidation of oral carcinogenesis and are of insignificant diagnostic value.

Carcinoma↗

PubMed1993

Prevention and early detection of oral, breast and cervical cancers: a practical approach in Indian context.

Cancer has emerged as a major killer disease in India. One-third of the total cancer load is constituted by oral, breast and uterine cervix cancers. Considerable knowledge is available on control strategies on these 3 major cancers and this can be transformed into the community through the individual health care practitioners. Oral cancer is preventable and both the precancerous and invasive lesions can be picked up easily by examination of the oral cavity. The occurrence of breast cancer in the country is on the increase. The poor survival rate indicates the impact of the major proportion of advanced cancer. An effective strategy comprising breast self-examination, examination by a physician and a mammography test, is described. Cancer of the uterine cervix is the commonest malignancy among females in several regions in India. An effective and definitive method is available in the form of Pap smear for the control of cervical cancer. An organised community screening programme is not economically viable at present. However, routine per speculum examination should be undertaken and this can result in clinical downstaging of cancer. Women above the age of 40 years should undergo regular Pap smear screening. Broad guidelines are presented for an opportunistic screening.

Adult↗

PubMed1992

Cancer control programme in India: opportunities for implementation and evaluation.

Cancer is now being appreciated in India as an emerging public health problem. Approximately 600,000 new cancer cases occur in India every year, and the absolute number of new cancer patients will increase considerably, due to growth in the size of the population and an increase in the proportion of elderly persons due to improved life expectancy following control of communicable diseases. This emerging problem has received the attention of the Government of India, and some state governments within the Indian Federation have formulated National and State Cancer Control Programmes to deal with the situation. In the event of these programmes being implemented, consideration should be given now to measures of evaluation of the activities, as many of the indices, used to monitor programmes in developed countries, such as 15% reduction from peak cancer mortality, or in peak mortality from specific cancers, are not applicable in developing countries like India. Factors such as the pattern of tobacco habits in the community, knowledge, attitude and practice (KAP) patterns regarding cancer in the general population, referral practices, and the national pattern of extent of disease at presentation, gain considerable importance from the evaluation point of view. Our article mainly deals with the sources and the quality of baseline data for such factors and the realistic quantitative goals which could be set for the above factors.

Humans↗

PubMed1991

Remission of precancerous lesions in the oral cavity of tobacco chewers and maintenance of the protective effect of beta-carotene or vitamin A.

Participants in the intervention trials were fishermen (Kerala, India), who chewed tobacco-containing betel quids daily before and throughout the study period. Frequency of oral leukoplakia, micronuclei in oral mucosal cells, and alterations in nuclear textures were used as endpoints. Administration of vitamin A (60 mg/wk) for 6-mo resulted in complete remission of leukoplakias in 57% and a reduction of micronucleated cells in 96% of tobacco-chewers. beta-carotene (2.2 mmol/wk) induced remission of leukoplakia in 14.8% and reduction of micronucleated cells in 98%. Vitamin A completely suppressed and beta-carotene suppressed by 50% formation of new leukoplakia within the 6-mo trial period. After withdrawal of vitamin A or beta-carotene treatment, oral leukoplakias reappeared, frequency of micronuclei in oral mucosa increased, and nuclear textures reverted to those present before the administration of chemo-preventive agents. The protective effect of the original treatment could be maintained for at least 8 additional months by administration of lower doses of vitamin A or beta-carotene.

Areca↗

PubMed1991

Remission of oral precancerous lesions of tobacco/areca nut chewers following administration of beta-carotene or vitamin A, and maintenance of the protective effect.

Designs of intervention trials are based on results from a multitude of disciplines. In this study, a comparative analysis of various chewing mixtures used by groups from different geographical locations (Guam, Peru, Taiwan, the Philippines, and India) and their link to oral cancer incidences was used to trace the ingredients responsible for oral carcinogenesis among chewers. The usefulness of applying intermediate endpoints in intervention trials was examined by comparing the response of micronucleated mucosal cells and oral leukoplakia of chewers of tobacco-containing betel quids to the twice weekly administration of beta-carotene (180 mg/week), vitamin A (100,000 IU/week or 200,000 IU/week), and beta-carotene (180 mg/week) plus vitamin A (100,000 IU/week). A reduced frequency of micronucleated mucosal cells and remission of leukoplakias resulted following a 3- to 6-month treatment. The development of new leukoplakias was also inhibited. The various endpoints differed in degree and time course to the administration of beta-carotene and vitamin A. Following termination of the beta-carotene or vitamin A administration, micronucleated cells and leukoplakia recurred in the oral cavity of chewers who continued this habit throughout the trial period. Attempts were made to maintain the protective effect achieved by the treatment with relatively high doses of the chemopreventive agents. Vitamin A given at a level of 50,000 IU/week was able to keep the frequency of micronucleated mucosal cells at low levels for at least a 12-month post-treatment period, whereas beta-carotene administered at 60 mg/week was less effective in maintaining the protective effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Areca↗

PubMed1990

Quantitation of chromatin patterns by image analysis as a predictive tool in chemopreventive trials with vitamin A.

Nuclear textures of oral mucosal cells were quantitated by image analysis, and their suitability as markers in a chemopreventive trial explored. Subjects were chewers of tobacco-containing betel quids with well established oral leukoplakias. Treatment consisted of a weekly oral administration of vitamin A (200,000 IU/week) for six months. Leukoplakias regressed in 57.1% of the 21 trial participants. The original leukoplakias did not redevelop within four months after termination of treatment. For image analysis, biopsies were taken from leukoplakias of five chewers before administration of vitamin A, at the end of the administration, and four months after termination of treatment. Sections of paraffin-embedded biopsies were stained with the Feulgen reaction and submitted to quantitative image analysis of two parameters: variance of intensity and entropy. Both these parameters were significantly reduced in all five trial participants as a result of the six-month vitamin A treatment. During the post-treatment period, nuclei with condensed chromatin, as measured by the variance of intensity, reappeared in the mucosa of four of the five chewers examined, although no leukoplakias were detectable on visual examination of the oral cavity. The results indicate that the quantitation of nuclear textures in a small subpopulation of a chemopreventive trial could conceivably be a simple marker with a predictive value.

Biomarkers, Tumor↗

PubMed1989

Chemopreventive trials with vitamin A and beta-carotene: some unresolved issues.

The administration of beta-carotene (180 mg/week) plus vitamin A (100,000 IU/week) or vitamin A alone (200,000 IU/week) to chewers of betel quids in Kerala, India led to a reduction in the frequency of micronucleated buccal mucosal cells, a remission of oral leukoplakia, and an inhibition of the development of new leukoplakias. The advantages of this test system include a profound knowledge of exposure levels to tobacco-specific nitrosamines, areca nut-specific nitrosamines, and reactive oxygen species (ROS)-generating polyphenolics; the ease of quantitating micronuclei in exfoliated buccal mucosal cells and oral leukoplakia by noninvasive procedures; and solid information on the incidence of preneoplastic lesions and carcinomas. Some practical issues such as the level of nontoxic beta-carotene which could maintain the reduced frequency of micronucleated cells and the remission of oral leukoplakias for prolonged periods of time, the logistics of distributing beta-carotene to the many millions of smokeless tobacco users who are at elevated risk for oral cancer, and the possibility of using beta-carotene in the form of sweet potatoes or red palm oil, which could contain an economical source of beta-carotene for developing countries in which most of the tobacco chewers live, still remain unresolved.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1989

Commercial butane abuse: a disturbing case.

The case report discusses a 16-year-old girl with a history of commercial butane gas abuse over a year. As the patient had collected the empty cannisters, it was possible to calculate the quantity abused which is not usually possible due to lack of co-operation and lack of evidence. Other aspects discussed are the mode of inhalation, accessibility, and psychological consequences.

Adolescent↗

PubMed1989

Neuroleptic-induced parkinsonian side effects in the mentally handicapped.

Sixty-seven neuroleptic-mediated mentally handicapped subjects in a hospital were studied to determine the prevalence of Parkinsonian side effects. A Parkinsonism scale was devised and administered. Sixty-one per cent of the sample had mild to moderately severe side effects. Sex, age, cumulative and current chlorpromazine doses, cumulative and current anticholinergic doses and anti-epileptic medication status did not predict the Parkinsonism scores. Overt brain damage was not a predictor. The difference between the neuroleptic medicated group and neuroleptic free matched controls was highly significant indicating that the Parkinsonian type of movement disorder was related to neuroleptic medication.

Adult↗

PubMed1989

Lithium-induced changes in the body mass index.

A total of 117 manic-depressives who had been on lithium for a mean duration of 4.7 years were examined before lithium therapy and subsequently at intervals. Information relating to pre-lithium height and weight and current weight were determined and used to calculate the body mass index (BMI) for each individual. Other relevant variables such as age, sex, cumulative lithium dose, duration of therapy, thyroid profile and serum lithium levels were recorded. The results indicated that, although there was a nonsignificant increase in BMI for the whole population, lithium and sex were not significant predictors of any increase in BMI. In nearly 27% of patients BMI actually slightly decreased during lithium therapy. The overall conclusions from this study are that, in the population studied, lithium may not have exerted any pharmacological effects to increase BMI.

Adult↗