Search PubMed⌕ Search

Biomedical subjects

R Jain

Publications and source records attributed to R Jain.

At least 163 records · Page 9Linked to original sources
PubMed1993

Fluorescence postlabeling assay of DNA damage induced by N-methyl-N-nitrosourea.

We have used a new technique to assay DNA adduct by combining enzymatic digestion of DNA to nucleotides and fluorescence postlabeling. The assay relies on the selectivity of nucleotide chromatography by high-performance liquid chromatography and the sensitivity of fluorescence detection. This report describes the fluorescence postlabeling assay of N7-(N7-methyldGuo) and O6-methyl-2'-deoxyguanosine (O6-methyldGuo) in calf thymus DNA exposed to N-methyl-N-nitrosourea. Using a conventional fluorescence detector, fluorescence postlabeling assay detected 1 modified nucleotide/10(6) normal nucleotides in 100 micrograms DNA. Laser induced fluorescence detection offers a linear response of the chromatographic signal from 10(-13)-10(-16) mol fluorescent nucleotides (correlation coefficient, 0.998) improving the detection limit of the assay to 1 modified nucleotide/10(8) normal nucleotides in 10 micrograms DNA. Fluorescence postlabeling analysis of the authentic markers shows that both N7- and O6-methyldGuo can be assayed with similar detection sensitivity. However, the inherent nature of the instability of N7-methyldGuo, even under physiological conditions, makes its quantitation difficult by any postlabeling technique. O6-MethyldGuo, on the other hand, can be detected with sufficient selectivity and sensitivity by a fluorescence postlabeling assay. Quantitative efficiency of enzymatic excision and chemical postlabeling of O6-methyldGuo were validated by fluorescence postlabeling analysis of synthetic model DNA. Fluorescence postlabeling assay complements 32P-postlabeling assay for O6-methyldGuo without requiring the handling and disposal of radiolabel. Fluorescence postlabeling assay has potential, therefore, to monitor the level of O6-alkyldGuo in human DNA exposed to both environmental and chemotherapeutic alkylating agents.

Animals↗
PubMed1993

Simplified method for simultaneous determination of diazepam and its metabolites in urine by thin-layer chromatography and direct densitometry.

A direct densitometric method for determination of diazepam and its metabolites in urine was developed. The proposed procedure involves acid hydrolysis of urine specimens, thereby converting diazepam and its metabolites into benzophenones [2-methylamino-5-chlorobenzophenone (MACB) and 2-amino-5-chlorobenzophenone (ACB)]. It is followed by extraction with chloroform-isopropanol (3:1, v/v). The two benzophenones were separated on thin-layer chromatography plates using hexane-diethyl ether-acetic acid (80:10:10) as a mobile phase. Quantitation of the MACB and ACB spots was achieved by direct ultraviolet densitometry. The limit of detection was 0.5 micrograms per ml of urine for both benzophenones. The proposed method is simple, rapid, reproducible and has been found to be effective for direct determination of diazepam and its metabolites in urine.

Benzophenones↗
PubMed1993

Computed tomography of vertebral tuberculosis: patterns of bone destruction.

A retrospective analysis was performed of CT scans of 30 consecutive patients with a clinical suspicion or diagnosis of spinal tuberculosis. Four patterns of bone destruction were noted, namely, fragmentary, osteolytic, subperiosteal and well-defined lytic with sclerotic margins. The fragmentary type was most common (47%). Intervertebral disc destruction was always associated with contiguous vertebral body destruction. Associated paravertebral soft-tissue masses were seen in all patients. Epidural extension of disease was seen in 66% and showed a very good correlation with neurological signs on clinical evaluation. Bone fragments were detected in the epidural soft-tissue mass in 65% of patients with epidural extension of disease. CT appearances of bone destruction are highly suggestive of tuberculous osteomyelitis in about half the patients.

Adult↗
PubMed1993

Circulating immune profile in patients with pre-cancer and cancer of the cervix: a cross sectional study among Indian women.

To fully understand immune competence in subjects with precancerous and cancerous lesions of the uterine cervix, various markers of T and B cells in peripheral blood were evaluated. The cellular measures were the absolute numbers of CD2, CD3, CD22, CD25, CD4, CD8 and CD4/CD8 T cell ratio and serologic measures were the levels of cellular products ie interleukin-2 (IL-2) and soluble interleukin-2 receptors (SIL2-R). Eighty-five subjects were analysed, and diagnosed histologically as CIN (n = 33) and invasive cancer (n = 22). Thirty women with normal Pap test results served as controls. Results on cellular markers showed a significant decrease in peripheral blood lymphocyte counts in patients with higher grades of cervical lesions as compared to controls (CIN III P < 0.05 and invasive cancer P < 0.001). Similar trends were observed for CD22 cell counts (P < 0.001). A consistent decrease was observed for CD2 positive T lymphocytes in patients with higher grade cervical lesions only. In addition, a decrease in CD4-T cells with a relative increase in CD8 and CD25 cell count was observed in these groups of patients, leading to a considerable reduction in CD4/CD8 T-cell ratio. Results obtained on soluble cellular products revealed that serum levels of IL-2 and SIL2-R in patient groups were significantly higher than controls (P < 0.001). Preliminary findings indicated a host-vested cellular impairment, evidenced by immune deficit and immune-stimulation, in women with pre-cancer and cancerous lesions of the cervix.

Adult↗
PubMed1992

Molecular confirmation of BCR-ABL fusion in a chronic myeloid leukemia with a complex translocation involving chromosomes 9, 15, and 22.

We performed molecular studies to resolve the status of BCR and ABL in the bone marrow cells of a CML patient with a Ph chromosome resulting from a complex translocation involving chromosomes 9, 15, and 22. DNA digestion with BamHI, HindIII, and BglII, followed by hybridization to a bcr-specific 32P-labeled probe, showed a rearranged banding pattern confirming the involvement of the bcr locus in the translocation. Furthermore, total cellular RNA isolated from the marrow was subjected to reverse transcription into cDNA and amplified by PCR with primers specific for BCR-ABL fusion cDNA. The amplified products obtained from this patient and from a CML patient with the standard t(9;22) were both of the expected length of approximately 317 bp.

Adult↗
PubMed1992

Use of blood transfusion in management of anemia.

Transfusion of red blood cells is useful in restoring oxygen-carrying capacity in patients with symptomatic anemia. In general, physicians should avoid transfusing blood based on hemoglobin concentration alone. Instead, they should focus on the impact of anemia on the patient's symptoms and level of activity. The concern for HIV infection and viral hepatitis has only served to highlight the potential risks associated with homologous transfusion therapy. These concerns should be carefully considered, along with possible alternatives, before a decision is made to transfuse. It is important to define the cause of anemia and to institute appropriate corrective therapy. The availability of recombinant human erythropoietin offers an option in selected patients to reduce or eliminate the need for red blood cell transfusion.

Anemia↗
PubMed1992

A density-sensing factor controls development in Dictyostelium.

For an unknown reason, several genes expressed during Dictyostelium development are regulated by cell density. This is mediated by an 80-kD glycoprotein, conditioned medium factor (CMF), which is slowly secreted and simultaneously sensed by starved cells. To examine further this eukaryotic cell density-sensing mechanism, we have isolated a cDNA encoding CMF. The derived amino acid sequence of CMF shows no obvious similarity to any known protein and thus may represent a new class of eukaryotic intercellular signal. CMF antisense transformants do not aggregate, whereas normal development is restored by the addition of purified CMF protein. This suggests that CMF might synchronize the onset of development in Dictyostelium by triggering aggregation when a majority of the cells in a given area have starved, as signaled by CMF secretion.

Amino Acid Sequence↗
PubMed1992

HSV-IgA serum antibodies in cervical intraepithelial neoplasia and invasive cancer patients, and in their spouses: a case control study.

Class-specific IgG and IgA antibodies to HSV were assayed in women with CIN (76), invasive cancer (52) (histological diagnosis) and age-matched controls (119), employing HSV-2-infected HEp-2 cells as antigen during IFA assay. We observed an elevated geometric mean titre (GMT) of serum antibody (IgG five-to eight-fold and IgA four-to five-fold) for the entire spectrum of cervical lesions, as compared to controls. The odds of finding HSV-IgA antibodies were highest with CIN III (OR = 22.0), followed by invasive carcinoma, and CIN I & II (OR = 9.5 and 5.2), respectively. Furthermore, the investigations with respect to married couples (husbands and wives) who volunteered to participate in this study (33 cases and 47 control group) also indicated relatively high antibody titres and increased frequency of HSV sero positivity amongst husbands of cases as compared to their wives, as well as the control group males and females. The contribution of HSV infection in women and/or their husbands to the risk of developing abnormal cervical lesions was analysed after adjusting for the same in respective counterparts. It was observed that the risk was increased 14-fold with HSV-IgA positivity of women, and that HSV-IgA positivity of husbands (male partners) further increased the risk 16-fold. This preliminary observation shows the importance of serum HSV-IgA antibodies as a risk indicator in cervical precancer and cancer lesions in women without a history of recent genital herpes lesions. The serum HSV-IgA may also be taken as an indicator of "high risk" males.

Adult↗
PubMed1992

Real-time sonography of orbital tumours, Colour Doppler characterization: initial experience.

Fifty-seven patients with orbital tumours were examined with 3.5 MHz and 5 MHz real-time sector sonography. The lesions were evaluated for their echomorphology, relationship to anatomical structures of the orbit, and extra-orbital extension. Twenty-two patients were further evaluated by Colour Doppler Flow Imaging (CDFI). The lesions were located to four compartments, namely intraocular, intraconal, extraconal and extraorbital. An attempt was made to provide a histological diagnosis on the basis of clinical features and sonographic morphology. Colour Doppler flow patterns in 22 patients were correlated with the presumed or proven histological diagnosis in an attempt to detect and classify any specific patterns. Real-time US is an excellent screening procedure in the evaluation of orbital mass lesions. CT/MRI should be added in selected cases where extra-orbital extension requires evaluation. CDFI of tumours still being in its infancy it seems promising and may help in providing a more precise pre-operative histological diagnosis non-invasively.

Color↗
PubMed1992

CT diagnosis of macrodystrophia lipomatosa. A case report.

Radiographs and CT scans of a 45-year-old male with progressive enlargement of his right upper limb and shoulder are presented. Extensive soft-tissue hypertrophy with linear radiolucent bands (fat) limited to the lateral aspect of the limb were seen. Exostoses-like bony overgrowth were also seen along interphalangeal joints. At CT, hypertrophic adipose tissue intermingling with muscle fibers was demonstrated, a diagnostic finding distinguishing the lesion from plexiform neurofibrolipomatosis, Klippel-Trenaunay syndrome and other angiomatous lesions.

Arm↗