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Biomedical subjects

P G Herman

Publications and source records attributed to P G Herman.

At least 73 records · Page 4Linked to original sources
PubMed1974

Blood microcirculation in the lymph node in xanthomatosis.

Twenty-five New Zealand white rabbits were placed on an atherogenic diet for 7 to 160 days to induce xanthomatosis. The microvascular morphology of the popliteal lymph node was studied throughout the development of xanthomatous replacement. The lymph nodes were serially sectioned and studied histologically and by microangiography. In animals which were on the atherogenic diet for over 90 days, foam cells replaced almost all of the lymphoid elements. Xanthomata appeared first as islands in the subcortical area and later spread to the medullary cords and the cortex. The xanthomata were highly vascular and contained a rich and dense capillary network of 5 to 7 mu vessels which were incorporated in the normal blood supply of the lymph node. The richness of capillary supply exceeds the hypervascularity observed during the immune response. The morphology of the capillaries raises the possibility of angiogenesis.

Angiography↗
PubMed1972

Blood microcirculation in the lymph node during the primary immune response.

Microangiography performed after total blood replacement with contrast material provided complete visualization of the vascular structures of the lymph node. Starting of the 2nd day, there is capillary redistribution throughout the cortex of the lymph node. The previously rather avascular nodules dissolve, and the cortical lymphoid tissue becomes uniformly vascular. Beginning on the 2nd day and reaching its peak on the 5th day, there is a significant increase in diameter and density of the subcapsular and medullary cord capillaries. 15 days after the antigenic stimulus, the appearance of the microvasculature returns to normal. The postcapillary venules (the microvascular structures which follow the capillaries) are widely distributed throughout. Histologically, only a fraction of these venules have a high endothelial lining (HE venules). Therefore, it is suggested that among the postcapillary venules, those with high endothelial lining should be specifically denoted. Great individual variation in the number of HE venules was observed, and no correlation with the timing of the immune response could be established. Whether the microvascular changes described lead to cellular change or are mere expressions of it cannot definitely be stated. However, the significant hypervascularity along the intranodal lymph pathways and the diffuse, even redistribution of the capillaries and postcapillary structures could greatly facilitate the humoral and cellular exchange between the circulating blood, the circulating lymph, and the tissues of the lymph node.

Angiography↗
PubMedDate not supplied

Mesenteric desmoid of the appendix--a case report.

A case of an isolated mesenteric desmoid (fibroma) is presented with two unusual characteristics. First, it arises from the mesentery of the appendix. Second, it presents as a twisted desmoid. The CT and US characteristics are presented. This patient was without risk factors for mesenteric fibrosis such as Gardner's syndrome or previous surgery.

Appendiceal Neoplasms↗
PubMedDate not supplied

Accuracy and its relationship to experience in the interpretation of chest radiographs.

One hundred chest radiographs, randomly selected from a hospital population, were read by 8 radiologists at 4 different levels of training and experience. All statements in the 800 interpretations were analyzed for accuracy. The analysis was based on deviation from a "true" report. Approximately 26% of significant and potentially significant statements were errors. Eighty per cent of these were false negative, 20% false positive. While significant individual differences in interpretive accuracy were found, there was no consistent pattern related to the duration of training beyond the first year of residency. Once an individual's radiologic education has progressed beyond a fundamental level, individual reader characteristics overshadow experience in the accuracy of chest film interpretation.

Diagnostic Errors↗