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Biomedical subjects

P G Herman

Publications and source records attributed to P G Herman.

At least 55 records · Page 3Linked to original sources
PubMed1979

Microvascular alterations in the lymph node during the BCG-induced immune response.

Previous studies have shown significant microvascular changes during the evolution of the immune response. In order to assess the BCG-induced microvascular alterations in the lymph node, we injected the left foot pad of 23 rabbits with 1.6 x 10(6) live BCG/kg weight; the right side served as control. Following a period of 1 to 50 days, microangiography and histology of the popliteal lymph nodes were carried out. On the side where BCG was injected, the lymph nodes initially showed a moderately increased cortical, and later, a markedly increased medullary hypervascularity. Histologically, there was mixed mononuclear cellular infiltration followed by granuloma formation. This latter was temporally related to the florid medullary hypervascularity. No significant changes were present on the control side. The hypervascularity induced by BCG was more intense and longer lasting than that seen with other antigens such as Typhoid 0 or bovine serum albumin. The results indicate a prominent vascular component in the BCG-induced primary immune response within the regional lymph node.

Animals↗
PubMed1978

Pulmonary nocardiosis.

Six cases of pulmonary nocardiosis are reported. All patients were compromised hosts treated with corticosteroids and/or immunosuppressive agents. The clinical presentations ranged from malaise to respiratory failure. The radiological manifestations varied from a solitary nodule to extensive cavitary bronchopneumonia with distant dissemination. The diagnosis was made by sputum culture in one, open lung biopsy in 3, and at autopsy in 2 others. In 3 patients, in whom early diagnosis was made, the infection was controlled by sulfonamide therapy.

Adult↗
PubMed1978

Giant hyperplastic parathyroid gland in the mediastinum--partially cystic and calcified.

A large, calcified paratracheal mass was identified in a patient with secondary hyperparathyroidism. The mass proved to be a giant, calcified, cystic, hyperplastic parathyroid gland. Radiographic and ultrasonic imaging techniques were quite useful in diagnostic evaluation. Whenever a calcified mediastinal or neck mass is discovered, especially in a patient with hyperparathyroidism, parathyroid enlargement should be a diagnostic consideration.

Calcinosis↗
PubMed1978

Improving performance by multiple interpretations of chest radiographs: effectiveness and cost.

The accuracy and cost of four methods of duplicate reading were evaluated. Eight radiologists interpreted 100 random chest radiographs. Using a third independent interpretation to resolve disagreements between pairs of readers ("Pseudoarbitration") was the most effective method overall, reducing errors 37%, increasing correct interpretations 18%, and adding 19% to the cost of an error-free interpretation. Resolving disagreements in facor of positive diagnoses was the best method for reducing omissions, but it almost doubled false-positive diagnoses. The choice between single and multiple interpretations must be evaluated in each clinical setting and should consider expected improvements in accuracy, implications for patient care, and additional costs.

Cost-Benefit Analysis↗
PubMed1978

Pulmonary actinomycosis. A report of three cases.

The diagnosis of thoracic actinomycosis is readily made when the patient presents with the constellation of poor oral hygiene, pulmonary infiltrates, empyema, sinus tracts, and osteomyelitis of the ribs. However, in the absence of rib and chest wall involvement, the disease may be overlooked. Three cases of primary pulmonary actinomycosis are presented showing three different pulmonary forms of the disease and comprising (a) subacute patchy pulmonary infiltrates, (b) a cavitary lesion simulating tuberculosis, and (c) a central mass lesion simulating bronchogenic carcinoma.

Actinomycosis↗
PubMed1978

The pulmonary-renal syndrome.

The pulmonary-renal syndrome is characterized by the coexistence of life-threatening pulmonary hemorrhage and renal disease in individuals without any concomitant destructive pulmonary disease or coagulopathy. Six patients fulfilled the above criteria despite diverse etiologies and pathomechanisms of disease. Two patients showed evidence of anti-glomerular basement membrane antibodies, while three others showed immune complexes in their kidneys. Therefore, it is likely that immunologic events play an important pathogenic role in this syndrome, explaining the effectiveness of nephrectomy as demonstrated in these patients. The chest radiograph was a reliable indicator of the extent of the pulmonary hemorrhage and was representative of the clinical presentation and blood gas levels. During the recovery phase the radiographic findings lagged somewhat behind the clinical improvement in the gas exchange.

Adult↗
PubMed1977

Omissions in radiology: faulty search or stringent reporting criteria?

Selected difficult chest radiographs were interpreted by 10 radiologists and then reread in a Focused Search condition that directed readers' attention to film regions containing frequently omitted findings. The percentage of true abnormalities reported at any level of confidence increased from 49.3 to 68.3 between the usual and Focused Search conditions. However, the corresponding percentage of significant false positives also increased from 4.6 to 10.6. The separate ROC curves from each condition could be superimposed and the data fit by a single ROC curve. Thus, the reduced omissions in Focused Search were the result of less stringent criteria for reporting the presence of abnormal findings, rather than an enhanced ability to detect abnormalities. There was no evidence that the original omissions were abnormalities simply overlooked in faulty initial searches.

Boston↗
PubMed1977

Renal microvasculature following papillary resection.

Surgical papillectomy was performed on 39 rabbits. Microvasculature initially remained normal. After cortical fibrosis occurred, a diversion of the blood flow from the cortex to the medulla was noted. Cortical atrophy following papillary loss is not secondary to microvasculature insufficiency, but is a consequence of obstruction of the collecting ducts. The physiologic changes which follow papillectomy are due to interruption of the loops of Henle and cortical scarring.

Animals↗
PubMed1977

The diagnostic accuracy and complications of closed lung biopsies.

The diagnostic yields and complication rates of closed lung biopsies were determined by responses to a questionnaire. Of 5,255 procedures reported, 30% were aspiration biopsies (AB), 7% tissue core biopsies (CB), 2% trephine biopsies (TR), 37% bronchial brush biopsies (BB), and 23% transbronchial biopsies (TB). Of these biopsies, 70% were done for suspected neoplasms. The diagnostic accuracy rates were: AB=82%, CB=84%, TR=86%, BB=61%, and TB=56%. Mortality rates were: AB=0.1%, CB=0.3%, TR=2.9%, BB=0.0%, and TB=0.3%. Transthoracic needle biopsies (AB, CB) had the highest overall diagnostic accuracy, with an associated low mortality and moderate morbidity.

Biopsy↗
PubMed1976

Unusual noninfectious granulomas of the lung.

Illustrative cases of pulmonary granulomas with angitis and plasma cell granuloma of the lungs are presented. Experimental evidence suggests that the common pathogenesis of these processes is a cell-mediated immune response. Radiographic findings of these entities--nodules or infiltrates, some with cavities--are non-specific. Effective treatment is available for some of these processes. Lung biopsy as early as possible is recommended.

Adult↗
PubMed1976

The value of consultation among radiologists.

The value of group consultation in improving the accuracy of radiologic diagnosis was assessed. Abnormalities on 24 films were pointed out to six groups of three radiologists each. They were asked to reach a specific diagnosis for each case. Accuracy was compared in three settingss: (1) without consultation; (2) with consultation leading to a diagnosis by group consensus; and (3) with consultation followed by independent diagnoses. The accuracy of over 75% of the radiologist improved after consultation in either setting. The extent of improvement was inversely related to the initial accuracy level of the individual. When two or three radiologists agreed initially, they were more frequently correct than not. Group discussion followed by individual diagnosis is a practical approach to radiologic consultation.

Diagnostic Errors↗
PubMed1976

Regional blood flow to the lymph node during the immune response.

In 62 New Zealand white rabbits the regional blood flow to the popliteal lymph node was determined using the microsphere distribution and the Rb86C1 indicator methods. In 20 animals local immune response was induced with typhoid O antigen and in 7 with bovine serum albumin. The regional blood flow of the popliteal lymph node was 0.57 ml/gm/min. During the immune response the blood flow and weight changes were strictly proportional. The lymph node has the capacity to maintain its blood flow, even following significant enlargement.

Animals↗
PubMed1976

The lymph node in experimental xanthomatosis.

There is significant, progressive replacement of the lymphoid elements of the lymph node by foam cells in experimental xanthomatosis. These cells first form islands in the subcortical area. Subsequently they involve the medullary cords and finally, they replace the cortex. The xanthomata are higly vascular, consisting of a dense capillary network of samall and short capillaries. These newly visualized capillaries are fully integrated and incorporated in the normal blood supply of the lymph node. No significant distortion of the larger venules and arterioles were observed. It is noteworthy to observe the great capacity of the vascular supply of the lymph node in reacting to situations of significant enlargment and replacement of the lymphoid elements.

Animals↗
PubMed1976

Microcirculation of the lymph node with metastases.

Microangiographic and histologic examination of the popliteal lymph node was performed on 49 rabbits 3 to 55 days after V2 tumor implantation into the hind paw. Control animals received subcutaneous tissue extract from normal rabbit donors. During the first 10 days after the tumor implant from an allogeneic animal donor, the draining lymph node exhibited a hypervascular response which after 2 weeks gradually subsided. Subsequently, during the early stages of lymph node metastasis there was still hypervascularity adjacent to the metastatic deposit. In about 4 weeks the metastases became more established and surrounded by layers of plasma cells. The hypervascular changes of the surrounding lymph node subsided by this time. In lymph node metastases the microvasculature could be an indicator of the immunologic activity of the host.

Angiography↗
PubMed1975

Interacinar pathways in the human lung.

Normal lung specimens from patients 18 to 86 years of age were inflated, fixed, and cleared. After micropuncture of the distal airspaces and injection of silicone rubber, the dissemination pattern was studied by cinematography. Free interacinar flow was commonly observed. The major pathways of spread among adjacent acini were the interacinar ducts. These were short, tubular structures 200 mum in diameter that were continuous with respiratory bronchioles and alveolar ducts. The flow of silicone rubber was impeded only by the septa of the secondary lobule of Miller. Our finding support the view that the smallest morphologic unit of airspace disease is more likely to be the secondary lobule than the acinus.

Adolescent↗
PubMed1975

Disagreements in chest roentgen interpretation.

Each of 100 chest radiographs selected randomly from a hospital population were read by five experienced radiologists. The films were rich in abnormal findings. Disagreement analysis was performed considering the entire content of the interpretation. The disagreements were graded by a panel as to type (false negative, false positive, and indeterminate) and significance. The overall repeatability of the panel's performance was 75 percent. Forty-one percent of the reports contained potentially significant errors and 56 percent indeterminate disagreements. Among all errors 78 percent were false negatives and 22 percent were false positives. The error rate varied among readers. An average of 25 percent of important findings were omitted by an individual reader. An association between specific abnormalities and the types of disagreement was found.

Diagnostic Errors↗