Biomedical subjects

R H Kirschner

Publications and source records attributed to R H Kirschner.

5 recordsLinked to original sources

PubMed1979

Scanning electron microscopy of infective endocarditis.

As part of a study of the development of infective endocarditis in ncarcotic addicts, we sought to establish the feasibility of using scanning electron microscopy (SEM) to view the surface characteristics of human heart valves obtained at autopsy. Normal and infected heart valves from humans and animals were obtained at autopsy, fixed in formalin, and processed for SEM. Parallel samples from immediately adjacent regions were processed for light microscopy. Active and healed endocarditis were readily recognizable by SEM, and the observations correlated well with those made by light microscopy. The advantage of SEM in the study of endocarditis is that it provides significant information about damage to the endocardial surface across the entire valve. The relative proportions of fibrin, platelets, leukocytes, exposed stromal connective tissue and bacteria on the surface of a lesion can easily be analysed. SEM may prove particularly useful in the study of the pathogenesis of the early lesions of infective endocarditis on previously "undamaged" valves.

Animals↗

PubMed1977

Characterization of the nuclear envelope, pore complexes, and dense lamina of mouse liver nuclei by high resolution scanning electron microscopy.

We have used high resolution scanning electron microscopy (SEM) to study the nuclear envelope components of isolated mouse liver nuclei. The surfaces of intact nuclei are covered by closely packed ribosomes which are distinguishable by SEM from nuclear pore complexes. After removal of nuclear membranes with the nonionic detergent Triton X-100, the pore complexes remain attached to an underlying, peripheral nuclear lamina, as described by others. The surface of this dense lamina is composed of particulate granules, 75-150 A in diameter, which are contiguous over the entire periphery. We did not observe the pore-to-pore fibril network suggested by other investigators, but such a structure might be the framework upon which the dense lamina is formed. Morphometric analysis of pores and pore complexes shows their size, structure, and density to be similar to that of other mammalian cells. In addition, several types of pore complex-associated structures, not previously reported by other electron microscope (EM) techniques, are observed by SEM. Our studies suggest that the major role of the dense lamina is associated with the distribution, stability, and perhaps, biogenesis of nuclear pore complexes. Treatment of isolated nuclei with a combination of Triton X-100 and sodium deoxycholate removes membranes, dense lamina, and nuclear pore complexes. The resulting "chromatin nuclei" retain their integrity despite the absence of any limiting peripheral structures.

Animals↗

PubMed1977

Cell and organelle shrinkage during preparation for scanning electron microscopy: effects of fixation, dehydration and critical point drying.

The critical point drying method of preparing samples for scanning electron microscopy is associated with a variable amount of specimen shrinkage. We studied the causes of this phenomenon is isolated mouse hepatocyte nuclei and in human erythrocytes and found that the critical point drying process itself caused most of the shrinkage that we observed (a 25-30% reduction in diameter in both specimens). Glutaraldehyde fixation and ethanol dehydration caused only minimal size reduction, prior to critical point drying. Substitution of an inert (ethylene glycol-ethylene glycol monethyl ether) dehydration technique did not alter the final result. Previous studies in our laboratory using high resolution SEM and correlative transmission microscopy of isolated nuclei have demonstrated that the shrinkage represents a miniaturization of the organelles in which all structural components retain their usual relationships.

Cell Nucleus↗

PubMed1976

Familial Sjögren's syndrome with associated primary salivary gland lymphoma.

Primary salivary gland lymphoma has been rarely documented in patients with or without Sjögren's syndrome. The association of disseminated lymphoreticular neoplasms with Sjögren's syndrome has been recognized, and the malignancy is usually widespread at the time of diagnosis. Familial occurrence of Sjögren's syndrome is likewise infrequently observed. In the present report we describe a patient with Sjögren's syndrome in whom a primary parotid gland lymphoma subsequently developed. In addition to the propositus, two of four siblings had definite evidence of Sjögren's syndrome and a third had several abnormal studies commonly associated with the disease. This observation suggests that genetic influence alone or in conjunction with other factors may facilitate the development of Sjögren's syndrome.

Female↗

PubMed1975

Epithelioid granulomas in Hodgkin disease. A favorable prognostic sign?

Histologic sections of spleen and liver prepared from tissue obtained during exploratory laparotomy and splenectomy in 91 untreated patients with Hodgkin disease were reviewed to assess the incidence and possible implications of noncaseating, epitheliod, sarcoid-like granulomas. The 17 patients with granulomas and the 74 patients without granulomas did not differ appreciably with respect to pretreatment indexes. All patients were observed for at least 15 months following laparotomy or until the time of death (range, 15 to 67 months; median, 25 months). The 17 patients with granulomas tended to have fewer relapses, longer survival, and lower incidence of subsequent herpes zoster infection compared to the 74 without granulomas. The presence of epithelioid granulomas in association with Hodgkin disease may reflect a host response to the tumor with favorable prognostic implications.

Adult↗