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Biomedical subjects

P Das

Publications and source records attributed to P Das.

At least 199 records · Page 11Linked to original sources
PubMed1978

A self-transmitting surface acoustic wave (SAW) pressure transducer.

We have developed a small, pressure-sensitive device using SAW oscillators, which is capable of being implanted and transmitting a signal several hundred feet. This paper presents the device and its prototypes, and data from the laboratory and live subjects.

Acoustic Stimulation↗
PubMed1977

Comparative study of retrograde amnesia in rats on active and passive avoidance tasks and spontaneous recovery of memory.

Naive and pretrained rats were trained in two active avoidance paradigms using a pole-climbing box and in a single-trial passive avoidance task using a T-maze. They were then subjected to amnestic treatments with electroshock, leptazol, pentobarbitone, or ether anesthesia. Single retention tests were given at 20-24, 44-48, or 68-96 h posttreatment. Electroshock and leptazol seizures produced retrograde amnesia in all three paradigms, provided that seizures were maximal and retention was tested before 48 h. Prior treatment with anticonvulsant drugs prevented amnesia. Ether and pentobarbitone anesthesia failed to produce amnesia in all three tasks. A trend of recovery from amnesia was observed in the electroshock and leptazol groups when tested for retention 48-96 h posttreatment. On the other hand, the non-amnesic control, pentobarbitone, and ether groups showed signs of forgetting at these longer intervals. Consolidation failure and/or retrieval block was surmised to be the cause of amnesia; recovery was the possible result of removing the block.

Amnesia↗
PubMed1976

Clinical diagnosis of abdominal tuberculosis.

One hundred and eighty-two cases of abdominal tuberculosis admitted to Swaroop Rani Nehri (SRN) Hospital, Allahabad, in the past 7 years have been reviewed. The clinical diagnosis of abdominal tuberculosis was made correctly only in 50 per cent of cases. About half the cases presented with chronic or acute on chronic intestinal obstruction. The remaining patients had vague pains, tender abdomen, constitutional symptoms or a mass in the abdomen. Diarrhoea was not frequent and fistula formation was rare. A chronic obstructive type of lesion was found not only in cases with a bowel lesion but also in patients with chronic miliary peritonitis and tuberculous mesenteric adenitis. Similarly, a lump was present not only in hypertrophic bowel tuberculosis but also in chronic miliary peritonitis and tuberculous mesenteric adenitis. On radiological examination false positive features such as fluid levels, bowel dilatation or even the 'string' sign were encountered. Liver and endometrial biopsies were positive in only a very few cases. Peritoneal biopsy was of considerable help, being positive in 88 per cent of ascitic cases and in 42-1 per cent of non-ascitic cases. Open peritoneal biopsy obtained after making a small incision in the right iliac fossa was found to be the most useful investigation in the diagnosis of abdominal tuberculosis. An ascitic fluid protein content of 2-5 g or more and a predominantly lymphocytic count of over 100/mm3 are diagnostic, but a cell count of 10/mm3 was recorded in one tuberculous case.

Abdomen↗
PubMed1975

Abdominal tuberculosis: demonstration of tubercle bacilli in tissues and experimental production of hyperplastic enteric lesions.

Material obtained from 35 cases of abdominal tuberculosis waps studied and an attempt was made to demonstrate tubercle bacilli by special staining of histological sections, culture and guinea-pig inoculation. Acid fast bacilli could be demonstrated in 80 per cent of cases. The remaining cases were also possibly due to tuberculous infection because granulomas with Langhans's type of giant cells and caseation or calcification of lymph nodes were present. The bacilli were demonstrated in bowel tissue showing non-specific histology in 1 case. In 2 other cases with non-specific lesions in the bowel the bacilli were demonstrated in lymph nodes. Guinea-pig inoculation studies showed that hypertrophic lesions of the bowel with a non-specific type of reaction could develop after intraperitoneal injection of tubercular material. Although it cannot be said on the basis of this study that Crohn's disease is caused by tuberculous infection, it can be concluded that tuberculous infection can give rise to a Crohn's type of lesion.

Animals↗