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Biomedical subjects

J K Sharma

Publications and source records attributed to J K Sharma.

At least 37 records · Page 2Linked to original sources
PubMed1993

Human papillomavirus DNA sequences in adenocarcinoma of the uterine cervix in Indian women.

BACKGROUND: Infection with human papillomavirus (HPV) is considered to be the principal causal agent in the development of squamous cell carcinoma of the uterine cervix. Although adenocarcinoma of the cervix originates adjacent to the squamous epithelial neoplastic lesions, the etiopathogenesis of adenocarcinoma is not yet clearly understood. Recent studies have raised more controversy, rather than answering the question of whether specific HPV infection also plays a role in the development of adenocarcinoma of the cervix. Molecular DNA hybridization techniques were used to detect HPV types prevalent in both adenocarcinoma and squamous cell carcinoma of the uterine cervix, which is the most common cancer in Indian women. METHODS: Histologically confirmed, formaldehyde-fixed, paraffin-embedded tissue sections from 12 cases of adenocarcinoma and 30 cases of squamous cell carcinoma of the uterine cervix were analyzed retrospectively for the presence of HPV DNA types 6b, 11, 16, and 18 by both Southern blot hybridization and in situ hybridization. RESULTS: Of 12 adenocarcinomas, 5 (41.67%) tumors were positive for HPV DNA: All five cases were positive for HPV 16, and two (16.6%) of these were hybridized again to the HPV 18-specific DNA probe. All tumors were negative for HPV 6b and 11. In addition, no biopsy specimens were positive after hybridization with a mixed probe of HPV 31, 33, 35, 39, and 45. These results were compared to those obtained for 30 squamous cell carcinomas of the cervix. Although 20 (66%) were exclusively positive for HPV 16 and 6 (20%), more tumors were of HPV 16 related types as detected under nonstringent conditions of hybridization, only one (3%) was positive for HPV 18. The results of in situ hybridization were found to be in good agreement with those of Southern blotting. CONCLUSIONS: HPV 16 is the type present almost exclusively in squamous cell carcinoma of Indian women. A higher frequency of HPV 16 in adenocarcinoma of Indian women, in contrast to HPV 18, as reported from other regions, may be attributed to geographic variation rather than to histologic differences only, and both HPV 16 and 18 may be present in adenocarcinoma of the uterine cervix.

Adenocarcinoma↗
PubMed1992

A high frequency of human papillomavirus DNA sequences in cervical carcinomas of Indian women as revealed by Southern blot hybridization and polymerase chain reaction.

Ninety-six colposcopically directed biopsies from squamous epithelial carcinoma of the uterine cervix and 22 age-matched normal control biopsy specimens were examined by both Southern blot hybridization and polymerase chain reaction (PCR) for the presence of different human papillomavirus (HPV) DNA types. Cancer of the uterine cervix, which is the most common malignant disease in Indian women, showed a high frequency (98%) of HPV as compared to those reported from other parts of the world. HPV type 16 was found to be the dominant (64%) type while the frequency of HPV type 18 was very low (3%). On individual typing of HPV, no biopsy was found to contain any other known HPV types under stringent conditions of hybridization except a single case of HPV type 11. Only one case of double infection with HPV types 16 and 18 was recorded. Under low stringency conditions of hybridization with a mixed probe of HPV types 16 and 18, 29 additional biopsies were found to be positive. Southern blot hybridization alone detected HPV DNA in 92% of the cases but none in the controls. By PCR, six (6.25%) more cases and four (18.18%) healthy women were found to be positive for HPVs. Analysis of the physical state of HPV 16 indicated integration in about 70% of carcinoma cases while 30% of them were in episomal form. The findings suggest that infection with HPV is an important etiologic factor for the development of cervical cancer, that a number of such tumours may arise without HPV infection, and that integration of the viral DNA into host genome is not always essential for malignant progression.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

A simple and rapid method of high quantity DNA isolation from cervical scrapes for detection of human papillomavirus infection.

Infection with human papillomavirus (HPV) is an important etiological factor in the development of cervical cancer, and detection of the viral genome is of prognostic importance, particularly for preneoplastic lesions. We developed a simple, easy and efficient non-organic method of DNA extraction from cervical scrapes for reliable detection of HPV DNA sequences. The method involves incubation of cell nuclei in higher concentration of proteinase K at 65 degrees C for 2.5 h. Following prolonged incubation at higher temperature, the enzyme is autoinactivated and the DNA isolated can be used directly for analysis without further purification. The recovery of DNA is more than 95% and it can be easily cleaved by restriction enzymes and is suitable for amplification by the polymerase chain reaction (PCR). The whole procedure is carried out in a single Eppendorf tube and a large number of specimens can be processed at a time without any error of handling. DNA extracted from a single smear sample is sufficient to conduct as many as four different molecular biology tests. This provides an opportunity for verification of sensitivity, specificity and reliability of each test for diagnosis of HPV infection without resorting to biopsy.

Adult↗
PubMed1992

Analysis by polymerase chain reaction of the physical state of human papillomavirus type 16 DNA in cervical preneoplastic and neoplastic lesions.

Integration of human papillomavirus (HPV) DNA into the host cell genome is believed to be essential for malignant progression. However unambiguous detection of the physical state of HPV is a difficult and time-consuming procedure. To resolve this issue a simple, rapid and highly sensitive technique of polymerase chain reaction (PCR) has been utilized for detecting the physical state of HPV-16 DNA. Investigations were carried out in 122 cervical specimens comprising the whole spectrum of cervical lesions starting from cervical dysplasia to invasive carcinoma including HPV-16-positive normal controls. A pair of oligonucleotide primers specific to the E2 open reading frame, which is often deleted or disrupted following HPV integration, was used for the study. Distinction between episomal and integrated forms of viral DNA was accomplished by detecting amplification of the E2-specific fragment (1139 bp) in the PCR product. The PCR results were compared with those obtained by the conventional methods of Southern blotting, two-dimensional gel electrophoresis and chromosomal in situ hybridization; a high degree of agreement was observed between the methods. The findings indicate that although integrated forms of HPV-16 DNA were detected in more than 70% of cervical cancer specimens, integration was less frequent (23%) in severe dysplasia and carcinoma in situ. Only 2.5% of cases showed both episomal and integrated forms of HPV-16 DNA. The difference between episomal and integrated forms was statistically significant (P less than 0.01). The absence of integration in about 30% of cancer cases suggests that integration of HPV may not be necessary for malignant progression and alternative mechanism(s) of malignant transformation may occur without HPV integration. The PCR test thus provides an effective complement to Southern blotting and two-dimensional gel electrophoresis for accurate detection of the integration of HPV DNA.

Base Sequence↗
PubMed1990

Development of an avidin-biotin dot enzyme-linked immunosorbent assay and its comparison with other serological tests for diagnosis of glanders in equines.

A dot enzyme-linked immunosorbent assay (dot ELISA) was developed for diagnosis of glanders in equines. The test was based on the detection of IgG antibodies to Pseudomonas mallei antigens bound to nitrocellulose coated on plastic strips (dipsticks), the reaction being amplified by an avidin-biotin system with biotinylated anti-horse IgG and horseradish peroxidase-avidin D. Sera from 810 normal, six naturally infected and 48 sensitized equines were tested by this assay, and results were compared with complement fixation, indirect haemagglutination and counter-immunoelectrophoresis tests. Dot ELISA had the highest sensitivity, and was superior to other tests in that it was rapid and easy to perform, the results were easy to interpret, the assay was not influenced by anti-complement activity, and it was able to detect antibodies at an early stage. Testing of serum at 1:200 dilution is proposed for epidemiological screening.

Animals↗
PubMed1989

Cerebrospinal fluid free N-acetyl neuraminic acid levels--a diagnostic and prognostic test in meningitis.

Cerebrospinal fluid (CSF) free N-acetyl neuraminic acid (NANA) levels were estimated in 20 cases each of pyogenic and tubercular meningitis (TBM) and 10 controls. The levels of free NANA were significantly high (P less than 0.001) in pyogenic and partially treated pyogenic meningitis when compared to TBM. The CSF free NANA levels had direct correlation with severity of the disease, CSF sugar and protein levels in pyogenic meningitis. The CSF free NANA can even be a prognostic criterion in management of pyogenic meningitis. Higher the levels, poorer the prognosis.

Bacterial Infections↗
PubMed1988

Sister chromatid exchanges in the lymphocytes of patients with oral leukoplakia.

The incidence of sister chromatid exchange (SCE) was investigated in lymphocyte chromosomes of 59 patients with oral leukoplakia and 65 age- and sex-matched nonsmoking controls. The frequency of SCE was found to be 8.61 +/- 1.89 in patients with oral leukoplakia, which was significantly higher than the mean SCE value of 5.58 +/- 1.26 observed in normal controls. The frequency of SCE in patients with oral leukoplakia addicted to the single habit of betel with tobacco chewing, bidi/cigarette smoking, and combined habits of chewing and smoking of tobacco were found to be 7.95 +/- 1.63, 8.17 +/- 1.66, and 9.23 +/- 2.14, respectively. These values were also significantly higher as compared to the SCE values observed in normal controls.

Adult↗
PubMed1987

Clinical experience with the use of peripheral vasodilator in oral disorders.

Conventional therapies practised in the treatment of asymptomatic neuralgia, oral submucous fibrosis and paraesthesic numbness, are empirical and symptomatic in nature. These are usually prolonged and may be inadequate, impractical with complete or incomplete remissions associated with or without relapses. High dosages of drugs administered for longer duration, are also not infrequently without side-effects. With these problems in view, the clinical use of nylidrin hydrochloride a peripheral vasodilator, was experienced for over 10 years. Irrespective of age, sex and status, 97 cases were randomly extracted from the hospital and oral surgery clinical records. The projected sample included 33 cases of asymptomatic neuralgia, 58 cases of oral submucous fibrosis and 6 cases of numbness. Neuralgia, where mean age was 50 years, was treated with nylidrin hydrochloride, vitamin B-complex and carbamazepine. Oral submucous fibrosis where mean age was 38 years, was treated with nylidrin hydrochloride, vitamins A,E,B-complex, iodine, placental extract, local and systemic corticosteroids and physiotherapy. Paraesthesic numbness, following iatrogenic or accidental trauma to the affected nerve, was treated with nylidrin hydrochloride and B-complex therapy. Peripheral vasodilator administered in all 97 cases, initially contained low divided doses, which steadily were increased or decreased as per individual response. There were reportedly no side-effects, except complaints of flushingly warm skin. Supportive therapy with antibacterials, tranquilizers and analgesics, along with minor dental surgery, were given as and when required. The success rate was 72.16% in total, while individually it varied from 84.85% in neuralgia, 62.07% in oral submucous fibrosis and 100% in numbness.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Nucleolar organizer regions in patients with precancerous and cancerous lesions of the uterine cervix.

Nucleolar organizer regions (Ag-NORs) were studied in patients with cervical precancerous and cancerous lesions along with controls. The data revealed a statistically significant decrease of Ag-NORs in cancer patients, as well as in women with severe precancerous lesions as compared with controls. A similar decrease in the amount of Ag-staining was also observed in both cancer and severe dysplasia cases. The study suggests a possible relationship of Ag-NOR activity to malignancy.

Adult↗