PubMed Health⌕ Search

Biomedical subjects

J Knaack

Publications and source records attributed to J Knaack.

36 records · Page 2Linked to original sources
PubMed1975

Further observations on carcinoma in situ of the urinary bladder: silent but extensive intraprostatic involvement.

Of seven patients with carcinoma in situ of the urinary bladder in the absence of an associated papillary carcinoma, five were found to have silent but extensive intraductal prostatic involvement. In three of these the carcinoma in situ was associated with microinvasion. The mean age at the time of diagnosis was 68 years. All had symptoms characteristic of carcinoma in situ, including hematuria, dysuria, and urgency. In three patients the prostatic involvement was diagnosed on transurethral resection. In two it was discovered only after radical cystectomy. The prostatic involvement was neither suspected clinically nor has it been previously emphasized. Although three patients are alive, apparently free of disease up to 15 months postcystectomy, two have died, one of disease. The importance of prostatic assessment in the evaluation of the patient with carcinoma in situ of the urinary bladder is emphasized.

Aged↗
PubMed1975

On the ultrastructure of hibernoma.

An electron-microscopic study of hibernoma and a review of the histogenesis, development, and post-natal structural composition of brown and white adipose tissue are presented. The ultrastructural features of hibernoma include multivacuolated and univacuolated cells containing variable numbers of lipid vacuoles, abundant moderately pleomorphic mitochondria with transverse cristae, lysosomes, lipofuscin granules, pinocytotic vesicles, well-formed basal lamina, and prominent subplasmalemmal condensations. The latter have not been previously reported in hibernoma, brown adipose tissue or white adipose tissue, although gap junctions have been observed in brown adipose tissue of newborn mice. It is concluded that the ultrastructural observations support the concept proposed decades ago that hibernoma represents the neoplastic counterpart of brown adipose tissue.

Adipose Tissue↗
PubMed1975

A controlled sequential morphologic study of hyperacute cardiac allograft rejection in the rat.

A series of heterotopic cardiac allografts from ACI strain rat donors to ACI skin-presensitized Lewis strain recipients was examined by light and electron microscopy at intervals from 1 minute to 24 hours for a sequential morphologic study of hyperacute rejection. Syngeneic Lewis hearts grafts in ACI skin-presensitized Lewis recipients provided controls. Extensive platelet aggregation throughout the vasculature of the allografts in the presence of a largely intact endothelium was the initial morphologic event, which was present by 1 minute posttransplant and absent in all syngeneic controls. This was followed by widespread endothelial damage. Endothelial damage preceded neutrophil margination and emigration in the graft. Neutrophil degranulation or evidence of phagocytosis was not observed within the 1st hour. At 6 and 24 hours, degranulated forms were common and apparent extrusion of granule contents with progressive ischemic injury. Segmental occlusion of the vasculature by platelet plugs and progressive disruption and loss of capillaries combined with an increase in permeability may result in myocardial ischemia. Neutrophil-derived agents do not appear to be of major significance in hyperacute rejection during the early posttransplant phase, but may play a role in mediating myocardial injury if the allograft survives for alonger period. However, on morphologic grounds, it is suggested that microcirculatory hypoperfusion with resultant ischemia is a major determinant of myocardial damage and graft function. No significant change was noted over the observation period in peripheral neutrophil or platelet counts when compared to syngeneic controls, and a slight reudction in specific cytotoxic antibody titer in the allografts was immediate but very transient.

Animals↗
PubMedDate not supplied

Fibromatosis hyalinica multiplex juvenilis.

Electron microscopic study of a case of fibromatosis hyalinica multiplex juvenilis (FHMJ) has revealed entangled tubular structures and an abundance of particles 40-60 nm in diameter in the cytoplasm, in addition to the previously described dilatation of the cisterna of endoplasmic reticulum--the "fibril-filled balls." The development of a tumor in FHMJ, therefore, involves abnormal propagation of cells, organelles, and their secretory products. The morphologic findings and the natural course of the disease suggest that this entity may be bordered between an abnormal proliferation and a true neoplasm of fibroblastlike cells.

Child↗