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Biomedical subjects

J V Pitha

Publications and source records attributed to J V Pitha.

14 recordsLinked to original sources
PubMed1991

Effects of CO2 laser beam on cortical bone.

Sixteen bone blocks from two freshly amputated legs were used to study the effect of CO2 laser on cortical bone. They were divided into two groups. In Group I, the blocks were treated with CO2 laser using 1 mm spot (focused mode). In Group II, they were treated with CO2 laser using 3 mm spot (defocused mode). Two other variables were investigated: the power and time of exposure. Three histologic zones were observed: a superficial zone with black particle deposits (carbonization), an intermediate zone with fibrillations and enlarged empty lacunae, and a deep zone with normal appearing bone. The bony changes in the first two zones combined were superficial in all specimens and did not exceed 200 microns. Increased energy, a focused beam, and time of exposure were all associated with increased matrix changes. CO2 laser can be applied to cortical bone in vitro with minimal residual thermal damage.

Bone and Bones↗
PubMed1991

Spontaneous haematomyelia: a necropsy study.

Spontaneous haematomyelia (intramedullary spinal haematoma), is an uncommon event. Predisposing conditions have been reported including syringomyelia, pregnancy and delivery, angioma, spinal artery aneurysm, and haemophilia, but only rarely has a pathological evaluation been performed. Two such cases studied at necropsy are reported. In one case, the haematoma was restricted to the cervical spinal cord, while in the second case it extended from the medulla into the lowest thoracic cord segments. In both cases the haematomyelia was fatal. In the first case the clinical course was subacute, but in the other the course was more acute. Careful neuropathological examination showed no apparent cause for the haemorrhages.

Aged↗
PubMed1988

Vaterian cancer in siblings.

The simultaneous occurrence of Vaterian carcinoma in two siblings suggests a genetic influence in their pathogenesis. Their classic clinical presentation of obstructive jaundice and weight loss required pancreaticoduodenectomy for this neoplasm. Pedigree analysis revealed a third sibling who died from an unresectable periampullary malignancy. Neither of the probands exhibited, as late as the seventh decade, evidence compatible with a diagnosis of familial polyposis coli or Gardner's syndrome. Flow cytometry studies revealed an aneuploid distribution in one tumor and tetraploid in the other. The rarity of this neoplasm, in the absence of contributing epidemiologic factors, suggests that this is a pleotrophic manifestation of a cancer-prone genotype.

Adenocarcinoma↗
PubMed1988

Histologic and electrophysiologic changes following subepineurial hematoma induction in rat sciatic nerve.

The sciatic nerves of 34 rats were used to study the effects of intraneural, extrafascicular hematoma, exclusive of any other trauma. Electrodiagnostic, histologic, and electron microscopic techniques were used. The amount of nerve fiber damage was assessed using computerized planimetry. The effects of hematoma evacuation were also investigated. Changes consistent with partial denervation, such as prolongation of insertion activity and distal latency, and the presence of positive waves and fibrillations, were present in the blood-injected but not in the control groups. Degenerative nerve fiber changes localized to the area of hematoma were present in the blood-injected group and were significantly higher than those in the control group. Although there was a difference in the amount of nerve damage between the blood-injected and the hematoma-evacuated group (less damage), this difference was not statistically significant. These findings suggest that intraneural extrafascicular hematoma produces electrophysiologic and histologic evidence of axonal degeneration affecting nerve fibers in the vicinity of the hematoma. Early evacuation of the intraneural hematoma appears to slightly reduce the deleterious effects of the lesion.

Animals↗
PubMed1988

Delayed reaction to "lead" pencil simulating melanoma.

A 74-year-old man had sustained a penetrating lead pencil injury to his right lower leg at the age of fifteen. A dark gray macule occurred that remained unchanged for fifty-eight years. An enlarging black nodule appeared in this area, simulating a melanoma, when the patient was seventy-three years old. Histologic examination revealed exogenous pigment and a foreign body reaction.

Aged↗
PubMed1987

Occupational hydrocarbon exposure and renal histopathology.

A blinded, retrospective study of histological sections from ten hydrocarbon-exposed and twenty unexposed nephrectomized renal cell carcinoma cases was conducted to evaluate the histopathologic features present in the apparently normal kidney parenchyma removed with the tumor. Tissue sections from each of the thirty cases were independently reviewed by three consulting pathologists and scored using well defined criteria. Occupational hydrocarbon exposure indices were developed by a team of industrial hygienists and applied to the detailed occupational history of each exposed case. A positive correlation was observed between age and the total renal pathology score (rs = .40, p less than .03). No correlation was found between indices of occupational hydrocarbon exposure and renal pathology scores among exposed cases. No significant differences in renal pathology scores were noted when exposed cases were matched to unexposed cases by age, sex, and race. These results are limited by the inclusion of only cases with historical hydrocarbon exposures. It is recommended that a follow-up study be conducted, utilizing sensitive quantitative methods, to define what, if any, cytopathologic renal effects occur in conjunction with current occupational exposures to hydrocarbons.

Adult↗
PubMed1985

Ultrastructural studies of vascular lesions in experimental amyloidosis of mice.

Definite lesions of arteriolar capillaries have been demonstrated in early amyloid lesions of mice. Pathologic changes include multiple endothelial gaps, the loss of an identifiable basal lamina, variable degrees of endothelial alteration, and the presence of the developing amyloid lesions surrounding the affected vessels. Despite these changes, the vessels remain functional part of the local microcirculation as demonstrated by intravascular injection of electron dense markers. These structural changes of arteriolar capillaries explain the presence of circulating plasma as a constant and major component of the early amyloid lesions in these animals and on this basis may determine the time of onset and site of formation of the lesions. The vascular injury appears to be caused by immunologic reactions to injected foreign antigens which gain a close relation to the structures of these vessels.

Amyloid↗
PubMed1984

Adult T-cell leukemia: clinical and immunologic characterization of a nonendemic case.

A 56-year-old black man with nonendemic adult T-cell leukemia is reported, who presented with severe hypercalcemia and leukemic leptomeningeal infiltration but had no evidence of bone marrow involvement. His malignant cells were characterized by light and transmission electron microscopy, cytogenetics, and flow cytometry. The cells demonstrated the deeply indented or convoluted nuclei characteristic of endemic human T-cell lymphoma virus-associated cases. Surface phenotyping indicated the cells' origin to be from the mature, helper/inducer subset of T-lymphocytes. However, there was no clinical or laboratory evidence that the malignant cells retained immunoregulatory function. The clinical and immunologic features of this and other nonendemic cases are compared with those of patients from the endemic regions of Japan, the Caribbean islands, and the southeastern United States.

Biopsy, Needle↗
PubMed1983

Acute leukemia after successful chemotherapy for oat cell carcinoma.

A report of acute myelomonocytic leukemia following successful therapy for oat cell carcinoma is presented. The patient had been treated with extensive cytotoxic and radiation therapy, and was without clinical evidence of disease at one year follow-up. Eighteen months later, a peripheral smear revealed numerous blasts with monocytoid characteristics. This unusual presentation is discussed and compared with several other cases appearing in the recent literature.

Aged↗
PubMed1979

Subcutaneous fat necrosis in pancreatitis.

A case of subcutaneous fat necrosis as the initial manifestation of an attack of acute pancreatitis is presented. The accompanying features of respiratory distress syndrome, leukemoid reaction, shock, pleural effusions, and arthritis due to necrosis of periarticular fat are described. Autopsy findings are pancreatic pseudocyst, serofibrinous peritonitis, pleuritis, and pericarditis and fat necrosis not only in the subcutaneous fat but also in the pericardial, pleural, mediastinal, mesenteric, retroperitoneal, and pericalyceal fat.

Acute Disease↗
PubMed1977

Continuing disease process of calcific aortic stenosis. Role of microthrombi and turbulent flow.

Microthrombi with evidence of organization were observed in 10 of 19 calcified and stenotic aortic valves (53 percent). The organization that results from such thrombi may contribute to the deformity of the valve. Repetitive deposits of microthrombi, followed by organization and calcification, would explain the continuous process of stenosis in previously deformed aortic valves. The formation of such thrombi may be initiated by turbulent flow and other fluid dynamic factors.

Adult↗
PubMed1977

Significance of abnormal echoes in left ventricular outflow tract.

We have observed abnormal echoes in the left ventricular outflow tract in 4 patients: 3 of the subjects had bacterial endocarditis and the fourth patient had myxomatous degeneration of the aortic valve (floppy aortic valve). A single diastolic echo with fine high frequency fluttering was seen in the patient with the floppy aortic valve, whereas the patients with endocarditis had associated infection of the mitral valve and an aneurysm of the anterior mitral leaflet, which was represented by dense systolic echoes on the proximal part of the mitral valve...

Adult↗