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Biomedical subjects

A Murthy

Publications and source records attributed to A Murthy.

30 records · Page 2Linked to original sources
PubMed1984

Renal failure from metastatic breast carcinoma reversed by radiotherapy and chemotherapy.

We treated a patient who had acute renal failure secondary to obstructive uropathy from metastatic breast carcinoma. Attempts at ureteral catheterization and nephrostomy failed. Bilateral ureteral irradiation was given, followed immediately by chemotherapy, with relief of obstruction and normalization of renal function. Nineteen months later, the patient died; at that time, her serum urea nitrogen and serum creatinine levels were normal.

Acute Kidney Injury↗
PubMed1978

Combined irradiation and surgery in the treatment of stage II carcinoma of the endometrium.

Between January 1969, and August 1975, 40 patients with pathologic Stage II carcinoma of the endometrium were treated at the Joint Center for Radiation Therapy. The treatment policy included external and intracavitary irradiation combined with surgery. The majority of patients received 4000 mg/hours of radium exposure using a Fletcher-Suit applicator and 4000 rad whole pelvis external irradiation, followed by hysterectomy and bilateral salpingooophorectomy. Median age of the patients was 61 years (39--88) and the median follow-up of the patients still alive was 69 months (29--102). Relapse-free 5-year survival corrected for intercurrent disease was 83% and uncorrected, 78%. Overall survival was 80%. Five patients had relapsing disease, three patients failed at distant sites only, one patient died of treatment related complications, and two failed locally and distantly. There were no failures in the pelvis alone. Although the relationshop between histologic grade and failure is not statistically significant, there were four failures among the 12 Grade III patients compared to two failures in 27 with Grades I and II. Similarly, 4 of 12 patients with gross cervical involvement developed relapsing disease, but only 2 of 28 failed with microscopic cervical involvement. This treatment policy yields excellent survival and continues to be our treatment recommendation.

Adult↗
PubMedDate not supplied

Laminar differences in the spatiotemporal structure of simple cell receptive fields in cat area 17.

Previous studies of cat visual cortex have shown that the spatiotemporal (S-T) structure of simple cell receptive fields correlates with direction selectivity. However, great heterogeneity exists in the relationship and this has implications for models. Here we report a laminar basis for some of the heterogeneity. S-T structure and direction selectivity were measured in 101 cells using stationary counterphasing and drifting gratings, respectively. Two procedures were used to assess S-T structure and its relation to direction selectivity. In the first, the S-T orientations of receptive fields were quantified by fitting response temporal phase versus stimulus spatial phase data. In the second procedure, conventional linear predictions of direction selectivity were computed from the amplitudes and phases of responses to stationary gratings. Extracellular recording locations were reconstructed histologically. Among direction-selective cells, S-T orientation was greatest in layer 4B and it correlated well (r = 0.76) with direction selectivity. In layer 6, S-T orientation was uniformly low, overlapping little with layer 4B, and it was not correlated with directional tuning. Layer 4A was intermediate in S-T orientation and its relation (r = 0.46) to direction selectivity. The same laminar patterns were observed using conventional linear predictions. The patterns do not reflect laminar differences in direction selectivity since the layers were equivalent in directional tuning. We also evaluated a model of linear spatiotemporal summation followed by a static nonlinear amplification (exponent model) to account for direction selectivity. The values of the exponents were estimated from differences between linearly predicted and actual amplitude modulations to counterphasing gratings. Comparing these exponents with another exponent--that required to obtain perfect matches between linearly predicted and measured directional tuning--indicates that an exponent model largely accounts for direction selectivity in most cells in layer 4, particularly layer 4B, but not in layer 6. Dynamic nonlinearities seem essential for cells in layer 6. We suggest that these laminar differences may partly reflect the differential involvement of geniculocortical and intracortical mechanisms.

Animals↗
PubMedDate not supplied

Cell types and response timings in the medial interlaminar nucleus and C-layers of the cat lateral geniculate nucleus.

Previous evidence concerning the physiological cell classes in the medial interlaminar nucleus (MIN) has been conflicting. We reexamined the MIN using standard functional tests to distinguish X-, Y- and W-cells. Discharge patterns to flashing spots also were used to identify some cells as lagged or nonlagged, as previously done for the geniculate A-layers. Also, each cell's response timing (latency and absolute phase) was measured from discharges to a spot undergoing sinusoidal luminance modulation. Of 71 MIN cells, 48% were Y, 27% were W, 8% were X, and 17% were unclassifiable. Lagged and nonlagged discharge profiles were observed in each cell group, with 28% of all cells being lagged. Lagged cells displayed a response suppression and long latency to discharge following spot onset, and a slow decay in firing at spot offset that was often preceded by a transient discharge. These profiles were indistinguishable from those of lagged cells in the A-layers. MIN cells also were heterogeneous in response timing, displaying a range of latency and absolute phase values similar to that in the A-layers. We extended these analyses to 27 cells in the geniculate C-layers. In layer C, 35% of cells were Y, 10% were X, 25% were W, and 30% were unclassifiable. About 11% had lagged profiles, and were X-cells or unclassifiable cells. Layers C1 and C2 contained only W-cells and no lagged profiles. The range of timings in the C-layers was somewhat narrower than in the MIN. Overall, these results show that the MIN contains a greater variety of functional cell classes than heretofore appreciated. Further, it appears that mechanisms which create different timing delays in the A-layers also exist in the MIN and layer C. These timings may contribute to direction selectivity in extrastriate cortex.

Animals↗
PubMedDate not supplied

Adenoid cystic carcinoma of the cervix.

Adenoid cystic carcinoma constitute around 0.4 to 1.7% of all carcinomas of cervix. It generally presents in elderly age group, however few cases in younger age have also been reported. Majority of cases present in early stage. Though concluding statement regarding the results cannot be made from the cases accumulated from the various reported series, nonetheless this review shows that radiotherapy too is effective in early stage and even in stage I results with radiotherapy appear better than surgery. In advanced stage outcome is invariably poor. In early stage main pattern of failure is distant metastasis. Both local and distant failure are observed in stage III and IV. Though lung is the commonest site of metastases (51%), abdominal cavity and brain are also found to be involved in some cases. Limited experience shows effectiveness of high doses of cisplatin and multiagent chemotherapy. Cases of early stage disease having risk for metastases and local failure should be identified and managed with multimodality treatment using surgery for bulky disease with post-operative radiotherapy and chemotherapy. In advanced stages combination of chemotherapy and radiotherapy is required. Exenterative surgery for central failure has been used effectively. Overall no evidence of disease rate is found to be about 48%, with mean follow-up of 39 months.

Age Factors↗