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Biomedical subjects

R S Menon

Publications and source records attributed to R S Menon.

At least 73 records · Page 4Linked to original sources
PubMed1986

Absence of IgA nephropathy in patients with ankylosing spondylitis.

In 40 patients with ankylosing spondylitis (AS) no evidence for IgA nephropathy was obtained. This conclusion was based on the absence of hematuria and on the inability to find an increased incidence of IgA-containing immunoglobulin deposits in skin biopsies. Increased Clq binding assay was only found in those AS patients with anterior uveitis. In 26% of the skin biopsies perivascular mononuclear cell infiltrates were observed, and immunoglobulin deposits were seen in 65%. These facts suggest that the immunologic system is involved in the pathogenesis of this disease.

Adult↗
PubMed1985

Reversal of natural resistance to bouvardin (NSC 259968) in sarcoma 180 cells in vitro and in vivo by verapamil.

Reversal of natural resistance to bouvardin (NSC 259968) has been attained in vitro and in vivo, by the calcium influx blocker verapamil in sarcoma 180 cells insensitive to bouvardin. Verapamil increased the in vitro lethality of the tumor cells following exposure with cells for 1 and 3 h as a result of the cytotoxic effect of bouvardin. Similar results were observed in vivo when the tumor cells were exposed to verapamil and then treated with bouvardin, showing a significant percent increase in the lifespan to 30% and 45%. This suggested that this calcium channel blocker had interacted with tumor cell membrane to modulate the response of the cells, and make them more amenable to the drug action.

Animals↗
PubMed1985

Cell surface alterations in murine leukaemia P388 adriamycin-resistant cells: studies on lectin-induced agglutination and rearrangement of lectin receptors.

Cell surface alteration was studied in a subline of murine lymphocytic leukaemia resistant to the broad-spectrum anticancer agent adriamycin (P388/ADR) employing concanavalin A(Con A)-induced agglutination and rearrangement of lectin receptors. Con A induced more agglutination of P388/ADR when compared to the drug-sensitive parental cell line (P388/S). Studies on the redistribution of Con A and Ricinus communis agglutinin-I revealed a high percentage of P388/ADR showing internalized fluorescence, while a majority of P388/S displayed a uniform distribution of fluorescence on the cell surface.

Animals↗
PubMed1984

Effect of Tween 80 on adriamycin cytotoxicity in murine P388 leukemia.

Studies on mice bearing P388 adriamycin sensitive and resistant lymphocytic leukemia were carried out to compare antitumor activity of adriamycin dissolved in Tween 80 (10% in distilled water) with that of adriamycin dissolved in distilled water alone. The antitumor activity of adriamycin dissolved in acqueous solutions of Tween 80 was higher than that of adriamycin dissolved in distilled water against P388 leukemia sensitive to adriamycin. However, no change in the activity was observed in P388 leukemia resistant to adriamycin when the drug was administered either in aqueous solution of Tween 80 or in distilled water alone.

Animals↗
PubMed1984

Prostatic cancer treated by external irradiation at the Rotterdam Radiotherapy Institute.

Two-hundred-seventy-nine patients, mainly with prostatic cancer category T3NXM0 and T4NXM0 , have been treated by a full-course of external irradiation. Five- and 10-year survivals and relapse-free survivals are comparable to reports in literature. Complications in about 24% of all cases are acceptable but might be reduced in future by more sophisticated techniques. Important prognostic factors were the T-category of the primary, the histological grade according to WHO and according to Gleason, and to a lesser extent vascular invasion in the biopsy specimen and the diagnostic procedure: either transurethral resection or needle biopsy. Combinations of WHO-grade, Gleason-grade and T-category are possibly the best prognosticators . Persisting, positive transrectal cytology after the irradiation is probably an indicator of a slightly increased risk of metastasis. In spite of hormone therapy after evidence of metastasis, prognosis is poor and not significantly influenced by any pre-irradiation prognosticator.

Follow-Up Studies↗
PubMed1983

Cancer of the urinary bladder category T2, T3, (NxMo) treated by interstitial radium implant: second report.

Three-hundred-twenty-eight patients with bladder cancer category T2NxMo and 63 patients with category T3NxMo have been treated by 3 times 3.5 Gy external irradiation followed by a radium implant. Overall 5- and 10-year survival in the T2 category are 56%. In the T3 category they are 39% and 13%, respectively. The intercurrent death (i.e. without evidence of bladder malignancy) corrected actuarial survival percentage in the T2 category is 75% at 5 years and 69% at 10 years. The corresponding percentages in the T3 category are 62% and 59%. Prognosis is worsened by the following factors: more than 1 diagnostic transurethral resection, a pathological intravenous pyelography, non-papillary structure and poor degree of differentiation of the growth. Prognosis in category T3, as compared with category T2, is worse because of the prevalence of bad prognosticators in this T3 category. Therapeutic adaptation to these findings might improve prognosis in the future.

Aged↗
PubMed1983

Carcinoma of the urinary bladder category T3NxMo treated by the combination of radium implant and external irradiation: second report.

Forty-one patients with bladder cancer, T3NxMo, with a diameter not exceeding 5 cm, were treated by 3 times 350 rad external irradiation, radium implant at reduced dose, and an additional 3000 rad external irradiation ("Radium 55%"). Survival is excellent where there is a high or medium degree of differentiation without vascular invasion in the biopsy specimen; prognosis is poor if a low degree of differentiation is combined with vascular invasion. The future therapeutic approach will be adapted to this finding.

Brachytherapy↗
PubMed1983

Differential agglutination of P388 adriamycin-sensitive and P388 adriamycin-resistant leukemia cells.

Cell surface modification was studied in a subline of murine leukemia resistant to adriamycin (P388/ADR). Lectin-induced agglutination was used as a probe. Agglutination was studied using two plant lectins, wheat germ agglutinin (WGA) and Ricinus communis agglutinin-I (RCA-I). A 7-fold higher amount of WGA and 14-fold higher amount of RCA-I were required to bring about minimum agglutination of P388/S as compared to P388/ADR. The present studies clearly indicate a change in the plasma membrane of P388/ADR cells.

Agglutination↗
PubMed1982

Carcinoma of the urinary bladder T3NxMo treated by preoperative irradiation followed by simple cystectomy.

One hundred eighty-three patients with bladder cancer category T3NxMo (the diameter of the primary exceeding 5 cm), were treated by preoperative 40 Gy and simple cystectomy. Using only pretreatment information, the group with the best prognosis was characterized by a T3A-growth with a normal intravenous pyelography, with about a 75% cure rate. Before cystectomy, after irradiation the combination of a clinically assessed radiation-downstaged growth (T40GY less than 3) with normal urography, predicted the best chance of cure at about 80%. After cystectomy was performed, the best prognostic group could be most correctly identified: those patients with both microscopic downstaging of the primary ("P" less than 3) and no vascular invasion in the cystectomy specimen (CV-) combined with normal urography had an 81% chance of cure. This most favorable group constitutes 45% of all patients.

Aged↗
PubMed1981

Effect of bouvardin (NSC 259968) on the growth characteristics an nucleic acids and protein syntheses profiles of P388 leukemia cells.

The plant product Bouvardin (BVD; NSC 259968) exhibited high activity against P388 murine leukemia and B16 melanoma, but it was not effect against various other tumor models. BVD inhibited the synthesis of all the macromolecules, namely protein, DNA and RNA, in P388 cells in vitro. Protein synthesis was most susceptible to the drug action. However, DNA and RNA synthesis were affected to a lesser extent. Further studies revealed that BVD did not inhibit protein degradation in P388 leukemia cells.

Animals↗
PubMedDate not supplied

Investigation of BOLD contrast in fMRI using multi-shot EPI.

High resolution volume coverage of the brain in fMRI studies can be accomplished using multi-slice, multi-shot EPI. We demonstrate that the optimum contrast sensitivity in BOLD based fMRI experiments using multi-shot EPI is achieved by using the shortest possible TR values between segments and the longest tolerable echo train length. For a fixed paradigm time, acquiring the largest number of images under these conditions yields the best statistical detection thresholds. For a multi-slice multi-shot EPI fMRI study, the best approach is to perform the acquisition of all the segments in a single slice before continuing on to each of the slices in turn. Our results regarding the number of shots and TR are also applicable to other multi-shot techniques such as interleaved spirals.

Brain↗