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R Naik

Publications and source records attributed to R Naik.

At least 19 recordsLinked to original sources
PubMed1998

Endothelin-1 and insulin activate the steady-state voltage dependent R-type Ca2+ channel in aortic smooth muscle cells via a pertussis toxin and cholera toxin sensitive G-protein.

In single rabbit aortic smooth muscle cells, and at a concentration known to induce a maximum sustained increase of intracellular Ca2+ via activation of the steady-state voltage dependent R-type Ca2+ channels, endothelin-1 (10(-7) M) and insulin (80 microU/ml) were found to induce a sustained increase in cytosolic free Ca2+ ([Ca]i) levels that was significantly attenuated by pre-treatment with either pertussis toxin (PTX), cholera toxin (CTX) or removal of extracellular Ca2+. However, both PTX and CTX failed to inhibit the sustained depolarization-evoked sustained Ca2+ influx and [Ca]i elevation via activation of the R-type Ca2+ channels. Moreover, ET-1 and insulin-evoked sustained increases in Ca2+ influx were not attenuated by the selective PKC inhibitor, bisindolylmaleimide (BIS), or the specific L-type Ca2+ channel blocker, nifedipine, but were completely reversed by the R-type Ca2+ channel blocker, (-) PN 200-110 (isradipine). These data suggest that both insulin and ET-1 activate the nifedipine-insensitive but isradipine-sensitive steady state voltage dependent R-type Ca2+ channels present on rabbit VSMCs and these channels are directly coupled to PTX and CTX sensitive G protein(s).

Animals↗
PubMed1998

Lectins in the vulva. I. Normal vulvar epithelium and epithelium adjacent to vulvar intraepithelial neoplasia and squamous cell carcinoma.

Lectins were used to investigate the cell surface oligosaccharide expression in normal vulvar epithelium from premenopausal and postmenopausal volunteer women. In addition, histologically normal epithelium adjacent to high-grade vulvar intraepithelial neoplasia (VIN III) and adjacent to vulvar tumors was examined with lectins for evidence of a possible "field change" surrounding these vulvar lesions. Seventeen vulvar biopsies were obtained prospectively from volunteer women, and 20 and 40 cases, respectively, of VIN III and vulvar squamous cell carcinoma were randomly chosen from pathology archives. Thirteen of the 20 VIN cases and all 40 vulvar carcinomas contained at least 2 cm of histologically normal-appearing epithelium adjacent to the vulvar lesion suitable for analysis. No alterations to lectin binding in normal vulvar epithelium with respect to patient age, menopausal status, phase of menstrual cycle, estrogen therapy, or history of cervical intraepithelial neoplasia were shown. ABO blood group antigen status affected epithelial binding for lectins HPA and UEAI (p < 0.005 and p < 0.001, respectively). In addition, lectins SNA, MPA, and LCA identified markers of cellular differentiation and maturation. T-antigen expression (as shown by the lectin PNA) was almost universally present in histologically normal epithelium adjacent to VIN and vulvar tumors, contrasting with the lack of PNA binding in normal vulvar epithelium from volunteer women (p < 0.001 and p < 0.001), a finding suggestive of a local "field change" surrounding preinvasive and invasive vulvar lesions.

ABO Blood-Group System↗
PubMed1998

Lectins in the vulva. II. Vulvar intraepithelial neoplasia and squamous cell carcinoma.

This study used lectins as histologic probes to determine the cell surface oligosaccharide expression in different grades and types of vulvar intraepithelial neoplasia (VIN). Lectin binding patterns in metastasizing and non-metastasizing squamous cell carcinomas (SCCs) of the vulva were also compared to correlate lectin binding patterns with metastatic potential and other clinical/tumor characteristics. Twenty cases each of VIN epithelium, metastasizing SCC, and non-metastasizing vulvar carcinoma were randomly chosen from the pathology archives. Sixteen lectins were used to probe individual terminal oligosaccharide residues in formalin-fixed, paraffin-embedded tissue specimens from these cases through an indirect immunohistochemical technique. There were no differences in lectin binding patterns between the different histologic subtypes of VIN. In addition, there were no consistent differences between metastasizing and non-metastasizing primary tumors and no major differences in staining patterns between nodal metastases and the corresponding primary tumors. Furthermore, there was no identifiable correlation between lectin binding patterns and subsequent survival or local or regional recurrence; however, lectin staining of invasive tumor cells did appear to be related to local invasiveness. In addition, positive PNA binding was found to be a constant finding in each of the VIN and invasive SCC cases, confirming that the T-antigen becomes unmasked during the process of vulvar carcinogenesis. However, poorly-differentiated areas consistently showed absent lectin binding, suggesting loss of specific glycosyl transferase activities. In addition, the blood group "A" antigen appears to be lost during the process of tumorgenesis, although the blood group "O" antigen appears to be preserved.

Carcinoma in Situ↗
PubMed1998

Relation of mast cell, nerve and fibrosis in appendix.

The relationship of mast cells, nerves and fibrosis was studied in 50 cases of Appendix using simple histochemical technique. In the mucosa, the mast cell number was greater in the early stages of fibrosis. Both in the mucosa and submucosa mast cells were found closely associated with neural tissue. As the fibrosis increased this association between mast cells and neural tissue was retained only in the submucosa.

Appendicitis↗
PubMed1998

A study of 70 cases of cutaneous metastases from internal carcinoma.

A retrospective analysis of 70 patients with metastatic cutaneous nodules, was conducted in the department of pathology, Kasturba Medical College, Mangalore. The available clinical records and histologic material of these cases were reviewed. In last few years fine needle aspiration cytology (FNAC) was being used as the main diagnostic tool. The commonest primary site of cutaneous metastasis in this study was gastro-intestinal tract (46.7%) in males and breast (32%) in females. Abdomen (including umbilical nodules) was found to be the most frequent site for metastatic cutaneous nodule.

Female↗
PubMed1998

Mast cell numbers in lymphnode lesions.

Mast cells were counted in 50 axillary lymphnodes draining breast carcinoma and 50 other lymphnodes from various sites with different histological lesions. All the lymphnodes, except those with tuberculous lymphadenitis were associated with increase in the number of mast cells. Highest number of mast cells (mean 172.80/mm2) were found in filarial lymphadenitis and lowest in tuberculous lymphadenitis (mean 8.87/mm2). In the axillary lymphnodes draining breast carcinoma, higher mast cell count was observed in reactive nodes. As these lymphnodes showed micro-metastasis the mast cells gradually decreased in number, and with extensive metastasis only few mast cells were seen. On comparison, the reactive lymphnodes draining breast carcinoma and other reactive nodes, the latter were associated with more mast cells.

Axilla↗
PubMed1998

Paneth cell metaplasia in colonic adenocarcinoms.

The junctional mucosa of 49 colorectal carcinomas were studied for Paneth cell metaplasia. Twenty two cases (44.89%) showed Paneth cells in the junctional mucosa. The carcinomas were seen mainly in the age range of 51 to 60 years (38.4%) The occurrence of Paneth cell metaplasia was higher in the vicinity of tumours of ascending colon and in well differentiated grades of adenocarcinomas. This probably indicates the reactive host response in the junctional mucosa which is of better prognostic significance.

Adenocarcinoma↗
PubMed1997

Modulation of cytosolic and nuclear Ca2+ and Na+ transport by taurine in heart cells.

The effect of taurine on the different types of ionic currents appears to depend on [Ca]o and [Ca]i and may also vary accordingly to tissue or cell type studied. Using microfluorometry and Ca2+ imaging techniques, short-term exposure (5-10 min) of single heart cells to taurine was found to increase total intracellular free Ca2+ in a concentration-dependent manner. However, long-term exposure of heart myocytes to taurine was found to decrease both nuclear and cytosolic Ca2+ without significantly changing either nuclear or cytosolic Na+ levels, as measured by 3-dimensional Ca2+ and Na+ confocal imaging techniques. Long-term exposure to taurine was found to prevent cytosolic and nuclear increases of Ca2+ induced by permanent depolarization of heart cells with high [K]o. This preventive effect of taurine on nuclear Ca2+ overload was associated with an increase of both cytosolic and nuclear free Na+. Thus, the effect of long-term exposure to taurine on intranuclear Ca2+ overload in heart cells seems to be mediated via stimulation of sarcolemmal and nuclear Ca2+ outflow through the Na+-Ca2+ exchanger.

Animals↗
PubMed1997

Silver staining nucleolar organiser region (AgNOR) study in melanocytic skin tumours.

Silver staining nucleolar organiser regions (AgNORs) were studied in 35 cases of melanocytic skin tumours. In the 23 cases of benign melanocytic naevi AgNORs per nucleus were between 1.06 and 3.43 with a mean of 2.05. In the 12 cases of malignant melanoma the AgNORs ranged from 4.26 to 10.66 (mean 7.43). Since statistically significant difference in AgNOR counts between benign and malignant melanocytic skin tumours was noted, this technique may serve as a useful adjunct to routine histopathology.

Diagnosis, Differential↗
PubMed1997

Mast cell count in surgically resected appendices.

Two hundred appendices were studied for mucosal and submucosal mast cell counts. In histologically normal appendices mucosal mean mast cell count (47.63/sq mm) was more than submucosal mean mast cell count (44.27/sq mm). Those patients who were aged under 15 and above 46 years showed more mean mucosal mast cell count compared to others. In acute appendicitis both mucosal and submucosal mast cells were decreased and in subacute appendicitis their count was found to be intermediate between normal and acute appendicitis.

Adolescent↗
PubMed1997

Distribution of mast cells in the axillary lymph nodes of breast cancer patients.

Fifty mastectomy specimens of carcinoma breast were studied for pattern of mast cell distribution in their axillary lymph nodes. When all axillary nodes were free of tumour, the mean mast cell count was 35.75/sq mm. In the metastatic node the mast cell count was inversely proportional to the amount of metastatic tumour. The mast cell number decreased (25.64/sq mm) as the metastasis developed in any of the enlarged axillary nodes. Their count diminished further (23.55/sq mm) as the amount of metastatic tumour increased in individual nodes and when tumour involved all enlarged nodes. Mean mast cell count was lowest (10.50/sq mm) in metaplastic carcinoma. The mast cells in metastatic nodes were found mainly at the edges of tumour deposits.

Axilla↗
PubMed1996

Implication of the nucleus in excitation contraction coupling of heart cells.

In the present study, Fluo-3 Ca2+ measurement and confocal microscopy techniques were used in order to localize cytosolic []c and nuclear []n free Ca2+ distribution in resting and spontaneously contracting single heart cells from 10-day-old chick embryos. In resting single cells, the concentration of Ca2+ in the cytoplasm was lower than that in the nucleus. Increasing cytosolic free Ca2+ from 100-1600 nM gradually increased [Ca2+]n with a maximum capacity near 1200 nM. Results from Fura-2 microfluorometry and Fluo-3 confocal microscopy suggest a potential cross talk between the increase of cytosolic free Ca2+ and the uptake and release of Ca2+ by the nucleus during spontaneous contraction of single myocytes. Calcium waves in spontaneously contracting cells were found to spread from one cell to the next with the nucleus acting as a fluorescent beacon in which Ca2+ levels remained elevated for several milliseconds even after cytosolic Ca2+ had returned to near basal values. These results strongly suggest that the nucleus plays a negative and positive feedback role in controlling cytosolic free Ca2+ concentration during excitation-contraction coupling in heart cells.

Aniline Compounds↗
PubMed1996

Modulation of Ca2+ and Na+ transport by taurine in heart and vascular smooth muscle.

Using the whole-cell voltage clamp technique, taurine was found to affect different types of various ionic currents including T and L-type Ca2+ currents, slow Na+ and fast Na+ currents as well as the delayed outward K+ current. Also, in normal situations, taurine had no effect on the Na(+)-Ca2+ exchange current. The effect of taurine on the different types of ionic currents appears to depend on [Ca2+]o and [Ca2+]i and may also vary according to the tissue or cell type studied. Using standard Ca2+ imaging techniques, short-term exposure (10 to 20 min) of single heart cells and aortic vascular smooth muscle cells was found to increase total intracellular free Ca2+ in a dose-dependent manner. However, using 3-dimensional Ca2+ and Na+ imaging techniques, long-term exposure of heart and vascular smooth muscle cells to taurine was found to decrease both nuclear and cytosolic Ca2+ without significantly changing either nuclear or cytosolic Na+ levels. Long-term exposure to taurine was found to prevent cytosolic and nuclear increases of Ca2+ induced by permanent depolarization of heart cells with high [K+]o. This preventive effect of taurine on nuclear Ca2+ overload was associated with an increase of both cytosolic and nuclear free Na+. Thus, the effect of long-term exposure to taurine on intranuclear Ca2+ overload in heart cells seems to be mediated via stimulation of sarcolemma and nuclear Ca2+ outflow through the Na(+)-Ca2+ exchanger.

Animals↗
PubMed1996

Recurrent stage IB cervical carcinoma: evaluation of the effectiveness of routine follow up surveillance.

OBJECTIVE: To study the effectiveness of follow up surveillance in detecting recurrent disease following radical hysterectomy for Stage IB cervical carcinoma. DESIGN: Retrospective analysis of clinical records using a computerised database. PARTICIPANTS: Six hundred and seventy-four patients with Stage IB carcinoma of the cervix underwent radical hysterectomy and lymph node dissection. INTERVENTIONS: Standard follow up surveillance consisted of clinical history and physical examination six weeks post surgery, and subsequently three monthly for the first year, six monthly for the second year, and yearly thereafter until 10 years post-treatment. RESULTS: Of the 674 patients, 112 (17%) developed recurrent disease. In only 29/112 (26%) was recurrent disease detected at the time of routine follow up visits. Nearly half of the patients (44%) were referred by their general practitioner between visits to the clinic because of suspicion of recurrent disease. CONCLUSION: Routine follow up surveillance is ineffective in detecting recurrent cervical carcinoma. Only one in four recurrences were detected at the time of a clinical visit.

Adult↗