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C Korn

Publications and source records attributed to C Korn.

34 records · Page 2Linked to original sources
PubMed1989

Interferon-gamma-increased adherence of lymphocytes to high endothelial venules.

Recirculating lymphocytes specifically adhere to and migrate through endothelium lining high endothelial venules (HEV), using specific and non-specific receptor-ligand systems. Interferons (IFN) profoundly affect the traffic of lymphocytes. Therefore the effects of interferon-gamma (IFN-gamma) on lymphocytes with respect to their interaction with HEV endothelium in lymph nodes were studied using the frozen section assay. In addition the organ-specificity of T- and B-lymphocyte adherence to HEV was investigated. Lymphocytes from spleen and peripheral lymph nodes showed increased binding to HEV of up to 35% compared to control lymphocytes after in vivo administration of IFN-gamma. The specificity of their binding did not change in terms of T:B-cell ratios. Increased adherence was also found by preincubation of lymphocytes with IFN-gamma in The enhanced binding was not due to increased expression of Mel-14 homing receptors and LFA-1 molecules on T and B lymphocytes, as shown by fluorescence-activated cell sorter analysis and antibody-blocking studies in the frozen section assay. Apparently IFN-gamma induces an additional Mel-14-independent and LFA-1-independent adhesion mechanism on lymphocytes.

Animals↗
PubMed1988

Mutism associated with buccofacial apraxia and bihemispheric lesions.

Mutism following brain trauma is quite common, is usually transient, and recovery of speech is essentially the rule. Lasting total absence of speech without aphasia is highly unusual. Three such patients, two of traumatic and one due to vascular origin showing buccofacial apraxia (BFA) and computerized tomography (CT) evidence of bilateral frontal lesions are reported. It is suggested that complete lasting mutism associated with BFA is a result of bihemispheric lesions affecting mainly the opercular part of the inferior frontal gyrus and immediate adjacent regions.

Adult↗
PubMed1986

Light microscopical detection of single 5 and 20 nm gold particles used for immunolabelling of plasma membrane antigens with silver enhancement and reflection contrast.

To detect plasma membrane antigens, cytocentrifuge preparations of the macrophage-like cell line P388D1 were incubated with monoclonal antibodies and labelled with 5 and 20 nm gold particles conjugated to immunoglobulins or protein A. The 20 nm, but not the 5 nm, particles could be observed by reflection-contrast light microscopy. Single 5 nm particles, however, were clearly demonstrable with silver contrast enhancement, both in absorption contrast and in reflection contrast. The method proved to be compatible with cytochemical methods such as acid phosphatase.

Animals↗
PubMed1985

False localization of acid phosphatase activity in the nuclear envelope and endoplasmic reticulum of peritoneal macrophages.

Acid phosphatase cytochemistry using lead salt methods was performed on rat peritoneal macrophages obtained by the intraperitoneal injection of dextran five days previously. Lead precipitate was present in the nuclear envelope, the rough endoplasmic reticulum, Golgi apparatus and lysosomes in about 50% of these cells. The formation of reaction product appeared to be substrate-specific and was sensitive to sodium fluoride in all these sites. However, only in the nuclear envelope, the rough endoplasmic reticulum and Golgi apparatus could lead salt precipitation be prevented by (a) omission of the washing procedure following the incubation step, (b) postincubation in a medium containing sodium fluoride, or (c) washing in buffer containing lead salt. It is concluded that precipitation of lead salt does not prove the presence of acid phosphatase activity in these organelles. The formation of precipitate in these sites is probably due to a local matrix effect, facilitated by the persistence of acid phosphatase activity in the lysosomes and a suboptimal trapping efficiency of phosphate ions during the washing procedure which follows in the incubation step.

Acid Phosphatase↗
PubMed1985

The Word Retrieval Fluency Test: what does it assess?

The term fluency in aphasia is ambiguous. It can relate to the rate of speech--normal vs. laborious or the ability to retrieve words. In this report, to avoid confusion we refer to fluency in a word retrieval task. Different authors have ascribed defective performance on these tasks to Frontal Lobe Syndrome or Aphasia. Our patient material adds dementia as a causative condition. To determine whether subnormal test performance is due to generalized brain dysfunction or only to left hemisphere disorders, we tested left hemisphere damaged patients, without aphasia as well as right hemisphere damaged patients, obtaining non-significant differences between the two groups. This supports our experience that such a test is highly sensitive to generalized brain dysfunction i.e. to a variety of cerebral disorders and therefore seems not to be highly pathognomonic of aphasia.

Adolescent↗
PubMed1983

Characterization of the population of phagocytic cells in thymic cell suspensions. A morphological and cytochemical study.

Rat thymic phagocytic cells were characterized in vitro using various light- and electron-microscopical techniques. Thymic cell suspensions were mechanically prepared and enriched for non-lymphoid cells, which were predominantly phagocytic and of three types. Type I showed acid phosphatase (APh) activity in small granules dispersed throughout the cytoplasm and were mostly Ia antigen-positive, although the Ia membrane label varied in intensity and distribution among individual cells. Only a few cells had endogenous peroxidase activity. The type-I cells could not be clearly distinguished morphologically from type-II or -III cells, and most likely comprise precursors of both these cell types. Type-II were large pale cells with many slender cell processes. These cells had APh activity centrally positioned, were strongly positive for Ia on the cell membrane and were negative for endogenous peroxidase. The cytoplasm frequently contained Birbeck granules, which unequivocally classifies these cells as the in vitro equivalent of the interdigitating cells present in the medullary area of the thymus in situ. Type-III cells were rounded with a smooth or ruffled cell membrane and contained vacuoles and many phagolysosomes. They were strongly positive for APh which was present throughout the cytoplasm. About 50% of these cells were positive for endogenous peroxidase in a pattern resembling resident macrophages. The cells were negative for Ia antigens. Type-III cells mostly likely represent the macrophages found in the cortical area of the thymus.

Acid Phosphatase↗
PubMed1981

Trypanosoma cruzi: comparative studies of infectivity of parasites ingested by Triatoma infestans and those present in their feces.

Artificial feeding of the insects with whole blood containing trypomastigotes resulted in triatome infection; the parasites were present in the host feces after 15--30 days and, when inoculated into mice, elicited parasitemia in 100% of the cases and deaths in 20--70%. This mortality indicates a reduction of the original infective capacity of the bloodstream form, which kills 100% of the mice even when inoculated with a single trypomastigote. When triatomes were fed whole normal mouse blood containing culture forms of low infective capacity (TulL), mice inoculated with feces containing the progeny of the culture forms failed to develop a parasitemia. The absence of any infective capacity of these parasites was proven when the mice challenged with lethal doses of trypomastigotes 30 days after the fecal inoculations died at the same time as the controls. Mice injected with feces from triatomes fed culture forms with high infectivity for mice (TulB) developed patent parasitemia, indicating that triatomes may be infected by parasite forms other than bloodstream trypomastigotes. Experiments on infectivity of parasites present in the feces of triatomes fed TulL and TulB culture forms, also showed a single passage through the digestive tract of the insects did not significantly modify the infective capacity of the parasite population. When stomachs and intestines from insects fed TulB were processed separately, parasites obtained from the latter showed higher infectivity for mice than those obtained from the former.

Animals↗
PubMedDate not supplied

Biopercular lesions and acquired mutism in a young patient.

A 13-year-old patient developed complete mutism and buccofacial apraxia following toxic vasculitis due to a yellow scorpion sting. Language functions were preserved. A CT scan disclosed mainly biopercular infarcts. It is suggested that the lost control of vocalization and speech is associated with biopercular lesions and that a preserved right opercular region can take over this function in the presence of damage to homologous left opercular region.

Adolescent↗