Search PubMed⌕ Search

Biomedical subjects

H Kolb

Publications and source records attributed to H Kolb.

At least 343 records · Page 19Linked to original sources
PubMed1981

Galactosyl specific receptor on liver cells: binding site for tumor cells.

In this paper the recognition of various rat tumor cells by rat liver cells is demonstrated in vitro. A liver cell receptor involved in the binding process has been identified. The ultrastructure of the cell contacts was examined by transmission electron microscopy. Hepatocytes and Kupffer cells were isolated from rat liver by collagenase treatment and cell adhesion tests were performed with 4 different tumor cells types. Hepatocytes were found to bind Walker sarcoma cells, lymphoma cells and Yoshida hepatoma cells but not leukemia 5222 cells. Kupffer cells bound all tumor cell types. Normal blood cells were not bound under the same conditions. Recognition of tumor cells by hepatocytes was mediated by a galactose specific lectin on the liver cell surface as shown by hapten inhibition experiments with specific saccharides. Although Kupffer cells express a similar lectin-like receptor adhesion of tumor cells could not or only slightly be inhibited by galactose or related saccharides. It is concluded that the spontaneous adhesion of tumor cells to liver cells in vitro is a specific recognition event which in part is mediated by lectin-carbohydrate interactions.

Animals↗
PubMed1980

Analysis of lectin-dependent recognition of desialylated erythrocytes by Kupffer cells.

Kupffer cells isolated from the rat liver are able to bind neuraminidase-treated rat erythrocytes via a D-galactose-specific receptor on the cell surface. Binding of desialylated erythrocytes was inhibited by several mono- and oligo-saccharides related to D-galactose, but not by unrelated sugars. However, after phosphorylation at position 6 D-glucose was as good an inhibitor as D-galactose. Two synthetic glycoproteins, D-galactosyl-albumin and, at a higher concentration, D-glucosyl-albumin, strongly inhibit cell contacts. Lectin-mediated binding of desialylated erythrocytes is dependent on the presence of Ca2'ons, but independent of ATP formation and cell motility. It is concluded that binding of desialylated erythrocytes by rat Kupffer cells is mediated by a Ca2-dependent D-galactosyl/D-glucosyl-recognition system.

Animals↗
PubMed1980

A second type of horizontal cell in the monkey retina.

A second type of horizontal cell with a distinctly different appearance from the previously known horizontal cell has been seen in Golgi-impregnated monkey retinas. The new HII cell has a different dendritic branching pattern from the commonly described HI cell type, and it has a short convoluted axon with collaterals bearing small clusters of terminals. Comparisons of the two cell types at different retinal eccentricities show that HII cells have larger dendritic trees than HI cells in the foveal region but smaller dendritic trees than HIs in peripheral retina. Dendritic terminals of the new HII cell, like the HI cell, contact cone pedicles as lateral elements of the ribbon synapses. The isolated terminals or clusters of terminals borne by the short axon of the HII cell also contact cone pedicles as lateral elements rather than contacting rod spherules as lateral elements like HI terminal arborizations. Thus, the monkey like other vertebrates has at least two horizontal cell types which differ in morphology and synaptic connections.

Animals↗
PubMed1980

Transfer of experimental autoimmune insulitis by spleen cells in mice.

We have tested whether experimental insulitis induced by multiple subdiabetogenic injections of streptozotocin can be transferred by lymphocytes to normal recipients. C57BL/6J mice were treated on 5 consecutive days with 40 mg streptozotocin/kg body weight. 5 X 10(7) nucleated spleen cells from 20 animals which had developed hyperglycaemia with concomitant insulitis three weeks after the first streptozotocin-injection, were transferred into congenic thymusless C57BL/6J-nu/nu mice. The cell transfer led to lymphocytic infiltrations of pancreatic islets in 75% of the recipients. Hyperglycaemia was not observed. It is concluded that low-dose streptozotocin treatment induces cellular immune reactions against pancreatic islets.

Animals↗
PubMed1980

Spontaneous autoimmune reactions against pancreatic islets in mouse strains with generalized autoimmune disease.

The spontaneously autoimmune mouse strains NZB, NZB X NZW, MRL and BXSB have been examined for signs of autoimmune reactions against islet cells. Between 15 and 55 animals of each strain were tested. Infiltrates of lymphocytes and fibroblasts into pancreatic islets were found in more than 80% of NZB mice, in about 50% of MRL and NZB X NZW mice, and in less than 20% of BXSB mice. Infiltrates were not found in the exocrine portion of pancrea. All NZB mice had abnormal glucose tolerance. In the three other strains between 20 and 50% of animals had abnormal glucose tolerance. All mice had fasting normoglycaemia. The lesions in NZB mice were studied in more detail. It was found by ultrastructural analysis that in young mice pancreatic infiltrates consisted of lymphocytes and fibroblasts. Single lymphocytes were also seen outside the main infiltration area. After 2 to 5 months of age another type of infiltrate, consisting of lymphocytes and macrophages was observed. B-cell destruction by lymphocytes was apparent in both young and adult NZB mice. It is concluded that cellular autoimmune reactions against pancreatic islets may occur spontaneously as a consequence of immunological disorders in NZB, NZB X NZW and MRL mice.

Animals↗
PubMed1980

Analysis of T-lymphocyte subpopulations in juvenile-onset diabetics.

In juvenile-onset diabetics (JOB) subpopulations of T-lymphocytes in the peripheral blood have been analysed by the E-rosetting technique. We determined the number of 'low', 'intermediate' and 'high affinity' ('active') rosette forming T-cells by the use of three different lymphocyte:sheep red blood cell ratios in the assay. When comparing the percentage and absolute number of peripheral T-cells between twenty well controlled JODs and twenty normal persons a slight reduction was found in diabetics. Of the three T-lymphocyte subpopulations only active rosette forming cells appeared to be affected. We conclude that minor differences exist in number and characteristics of peripheral blood T-cells between well controlled JODs and normal persons.

Adolescent↗
PubMed1980

Fractionated total body irradiation and autologous bone marrow transplantation in dogs: hemopoietic recovery after various marrow cell doses.

Hemopoietic recovery was studied in dogs given 2400 R fractionated total body irradiation within one week and graded doses of cryopreserved autologous bone marrow. Complete hemopoietic recovery including histology was observed after this dose and sufficient doses of marrow cells. Doses of more than 5.5 X 10(7) mononuclear marrow cells/kg body weight were sufficient for complete recovery in all dogs, 1.5 to 5.5 X 10(7) cells/kg were effective in some of the dogs and less than 1.5 X 10(7) cells/kg were insufficient for complete recovery. Similarly, more than 30,000 CFUc/kg body weight were required for hemopoietic recovery. The optimal marrow cells dose which has been defined as the minimal dose required for the earliest possible recovery of leukocyte and platelet counts was 7-8 X 10(7) mononuclear marrow cells/kg body weight. It has been concluded that fractionated total body irradiation with 2400 R does not require greater doses of marrow cells for hemopoietic reconstitution than lower single doses and that the hemopoietic microenvironment is not persistently disturbed after this dose.

Animals↗
PubMed1979

Interactions between neuraminidase-treated lymphocytes and liver cells.

Neuraminidase-treated rat lymphocytes and rat hepatocytes spontaneously aggregate when mixed in vitro. Adhesion between cells is due to stereo-specific interactions between a mammalian hepatic membrane lectin and galactosyl residues which are exposed on the lymphocyte surface after removal of sialic acid residues. The hepatic galactose specific lectin may play a role in the accumulation of recirculating desialylated lymphocytes in the liver.

Acetylgalactosamine↗
PubMed1979

The inner plexiform layer in the retina of the cat: electron microscopic observations.

Neural connections of cells ramifying in the inner plexiform layer of the cat retina have been studied by serial section electron microscopy. Flat cone bipolars and invaginating cone bipolars segregate their axon terminals to different sublaminae of the IPL (sublamina a and sublamina b, respectively) where they relate to different subtypes of the same class of ganglion cell (a and b types respectively). Rod bipolar axon terminals end solely in sublamina b and synapse with amacrine cells (AI and AII). AI provides reciprocal synapses to clusters of rod bipolar axon terminals. The AII amacrine provides rod input to a type ganglion cells by means of chemical synapses and to b type ganglion cells through gap junctions with invaginating cone bipolar terminals. Amacrine cells exist which interconnect rod and cone bipolars, but some amacrines appear to be related specifically to neurons branching in particular sublaminae. Both large- and small-bodied ganglion cells have amacrine-dominated input while the medium-bodied ganglion cells with small dendritic trees have cone bipolar-dominated input.

Animals↗
PubMed1979

Isolation, characterization and radioimmunoassay of corticosteroid-binding globulin (CBG) in human serum -- clinical significance and comparison to thyroxine-binding globulin (TBG).

Isolation of the corticosteroid-binding globulin CBG was achieved by 5 chromatographical steps on cortisol Sepharose, QAE-Sephadex A-50, Con A-Sepharose and hydroxylapatite. The purity of the isolated CBG was demonstrated in polyacrylamide gel electrophoresis, SDS electrophoresis, immunodiffusion and ultracentrifugation. Microheterogeneity was shown in isoelectric focusing by 5 bands in the pH range of 3.7--4.2, which could be reduced to one major band after neuraminidase treatment. The equimolar binding of cortisol to CBG was demonstrated by binding studies. The association constant for cortisol was 2.8 x 10(8)M-1, for progesterone 1.7 x 10(6)M-1. From analytical ultracentrifugation, the molecular weight was calculated on 50 700; the sedimentation coefficient was 3.6 S, the partial specific volume 0.690 ml/g, the Stokes radius 38 A and the frictional coefficient ratio 1.5. A specific radioimmunoassay for CBG was established using the purified CBG for immunization, radioiodination and for calibration standards. The normal range of CBG levels in human serum was 2.4--4.4 mg/100 ml (mean +/- 2 SD). Studies were performed to compare the levels of CBG and thyroxine-binding globulin (TBG). No sex differences but a significant biphasic age dependence were observed for both proteins. In pregnancy and under oestrogen treatment of women and men, CBG was demonstrated to be the more distinct indicator of oestrogenic activity as compared with TBG, whereas the sensitivity of TBG was more pronounced to supposedly antioestrogenic substances like Danazol, and in severe disease. No coincidence of genetic CBG and TBG deficiencies have been found so far.

Amino Acids↗
PubMed1979

Pathology of acute graft-versus-host disease in the dog. An autopsy study of ninety-five dogs.

The morphology of graft-versus-host disease (GVHD) in canine radiation chimeras was studied by examination of autopsy tissue from 95 dogs including: 1) 13 healthy, untreated dogs; 2) 9 dogs given 1200 R total body irradiation and no marrow infusion; 3) 17 dogs given 1200 R and autologous marrow infusion; 4) 25 dogs given 1200 R and hemopoietic cells from dog-leukocyte-antigen (DLA)--identical littermates; and 5) 31 dogs given 1200 R and nonidentical DLA hemopoietic cells. Some of the dogs in Groups 3--5 received a postgrafting methotrexate (MTX) regimen of 0.25--0.5 mg/kg body weight on Days 1, 3, 6, and 11 and once weekly until Day 102. Prominent lesions were found in the small and large intestines, skin, and liver of dogs with allogeneic grafts. Skin lesions consisted of lymphocytic infiltrates of epidermis with necrosis of basal epidermal cells progressing to denudation. Gut lesions consisted of mucosal destruction progressing from crypt abscess formation to denudation. Liver lesions consisted of portal triaditis, plasmacytic and lymphocytic infiltrates, necorsis and atypia of small bile ducts, and scattered individual hepatocyte necrosis. These lesions were differentiated from changes caused by irradiation and MTX and were deemed characteristic of GVHD. The overall severity of GVHD lesions was less in the identical DLA group than in the nonidentical DLA group, and also less in dogs treated with MTX than in those not given MTX. The degree of lymphoid depletion in the lymph nodes, spleen, and intestinal lymphoid tissue was very similar in dogs with autologous and allogeneic grafts at comparable survival times. No specific evidence of pancreatic or renal involvement in GVHD was discovered.

Animals↗
PubMed1979

Autoimmune reactions against liver cells by syngeneic neuraminidase-treated lymphocytes.

We have found that the entrapment of neuraminidase-treated lymphocytes in the liver leads to the induction of autoimmune cellular cytotoxic reactions. Lymphocytes from mouse spleen and thymus were incubated with neuraminidase in vitro and injected i.v. into syngeneic recipients. Lymphocytic infiltrations into the liver were seen 7 days later with both types of cells. After repeated weekly injections of asialo-lymphocytes, destruction of liver tissue became apparent. Electron-microscopic studies showed that hepatocytes, fat storage cells, and endothelial cells were affected, mainly at the hepatic periphery. It is concluded that the adhesion of asialo-lymphocytes to liver cells induces their cytotoxic activity. Similar reactions may occur after paramyxovirus infection due to the action of viral neuraminidase.

Animals↗
PubMed1979

Discussion on atresia of oesophagus.

Combined malformations and dysmaturity are still the most important causes of postoperative complications and deaths in the treatment of congenital oesophageal atresia. Better results can only be expected if methods of therapy of these associated conditions can be improved.

Abnormalities, Multiple↗