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Biomedical subjects

T Neumark

Publications and source records attributed to T Neumark.

At least 19 recordsLinked to original sources
PubMed1991

Colloidal bismuth subcitrate causes sustained release of gastric mucosal prostaglandin E2.

Gastric application of high doses of colloidal bismuth subcitrate (CBS) stimulates mucosal prostaglandin E2 (PGE2) production, which is considered part of the mechanism by which the drug accelerates peptic ulcer healing. Whether therapeutic, orally administered, doses of CBS cause a sustained stimulation of prostaglandin production is not known. We have, therefore, determined gastric luminal release of PGE2 during 'steady-state' perfusion of the stomach with CBS (10 mg/ml; isotonic mannitol 5 ml/min) and 4 h after the last oral dose of the drug (240 mg b.d.) for 2 weeks (isotonic mannitol 5 ml/min) in 8 healthy volunteers. A significant increase in PGE2 concentrations (712 (409-1076) vs. control 334 (252-655) pg/ml; medians with Q50 ranges; P less than 0.02) and PGE2 output (12.5 (7.3-14.3) vs. control 4.8 (4.1-7.3) ng/15 min; P less than 0.02) occurred during gastric perfusion with CBS. A similar increase in PGE2 concentrations (630 (297-1429) pg/ml; P less than 0.02) and PGE2 output (12.6 (6.4-22.2) ng/15 min; P less than 0.02) was observed following treatment with CBS for 2 weeks. These results suggest that therapeutic doses of CBS cause a sustained stimulation of gastric mucosal PGE2 formation.

Adult↗
PubMed1990

Ultrastructural changes of human amniotic cells induced by natural human interferon-alpha.

Human interferon-alpha (Hu-IFN alpha) and phorbol myristate acetate (PMA), a direct activator of protein kinase C (PK-C), induce the translocation of protein kinase C from the cytosol to the membrane fraction. By the use of transmission (TEM) and scanning (SEM) electron microscopy we have shown that treatment of human amniotic cells (UAC) with Hu-IFN alpha resulted in profound changes in the shape, volume and ultrastructure of the cells. Most treated cells had enlarged nuclei with marginal condensation of chromatin. Nucleolar segregation, disintegration and clumping of nucleolar components were also observed. The number of interdigitating cell processes decreased and the cell surface microvilli became shortened. Similar ultrastructural alterations were induced by PMA also. All these functional and morphological data strongly support the hypothesis that protein kinase C is a key factor in IFN-mediated cell reactions.

Amnion↗
PubMed1989

Gap junctions between human T-colony cells.

T-cell colonies formed in liquid or semisolid cultures of stimulated human blood mononuclear cells were investigated under electron microscope. Typical gap junctions with five-layered structure were demonstrated between colony cells embedded in water miscible resin. The overall thickness of the junctional zones was less than 25 nm. The intercellular gap was demonstrated by lanthanum nitrate staining. Close membrane associations were observed after normal embedding with a junctional width of 20-35 nm corresponding to gap junctions. The functional importance of free communication between colony cells is discussed.

Colony-Forming Units Assay↗
PubMed1986

Combined 1H-NMR and vacuum dehydration study of rat muscles.

Combined NMR and the vacuum dehydration method were used to study the state of water in rat muscle. Comparative studies were carried out on muscles of young and old mature white rats. The spin-lattice relaxation time was measured as a function of water content. The single-exponential behaviour of the relaxation process indicates a normal fast-exchange process between the different fractions. The more elaborate analysis demonstrates the failure of the original fast-exchange model. It is proved that structural changes take place in the macromolecule/ion/bound water system of the muscle even at the beginning of dehydration. All the muscle water seems to be necessary to maintain the normal natural state of the muscle's molecular structure.

Age Factors↗
PubMed1986

Ultrastructural study of neuromuscular and vascular changes in connective-tissue diseases.

Ultrastructural changes of the neuromuscular and microvascular systems were investigated in muscle biopsies obtained from patients with rheumatoid arthritis, systemic lupus erythematosus, dermato- and polymyositis and progressive systemic sclerosis. Myofibrillar degeneration, Z-disc streaming, mitochondrial abnormalities, alteration of the T system and sarcoplasmic reticulum were the main ultrastructural alterations observed in biopsy material. At the same time, severe peripheral nerve-fibre lesions were also observed. Thickening of the basement membrane around capillaries was repeatedly demonstrated, above all in rheumatoid arthritis and progressive systemic sclerosis. Immunocomplexes around capillaries and small vessels as well as along the sarcolemmal basement membrane were also often demonstrated.

Adult↗
PubMed1985

Ultrasound diagnosis of carcinoma of the urachus.

In a 48-year-old man with dysuria and microscopic haematuria, pyelography, cystoscopy and bimanual bladder palpation showed no definite abnormality. Because of continued symptoms, ultrasound scanning of the abdomen was done three months later. The examination revealed a tumour in close relation to the top of the bladder. Malignant cells were aspirated at ultrasonically guided puncture, and a urachus tumour was suspected. For early diagnosis of urachus tumours, ultrasound investigation of vague bladder symptoms is required.

Adenocarcinoma, Mucinous↗
PubMed1979

Ultrastructural studies in rheumatoid polyneuropathy.

The biopsy material from the sural nerve of 8 patients suffering from rheumatoid arthritis and showing, with one exception, positive serological reactions, were studied by means of electron microscopy. All the patients were displaying sensory and sensomotor neuropathy. Besides hypermyelination the damage of Schwann cells, the destruction on unmyelinated fibres and the proliferation and degeneration of the vascular endothelium were observed. No inflammatory signs were seen around the peri- and endoneurial vessels.

Aged↗
PubMed1977

Cell-to-cell contacts between lymphoreticular cells in rheumatoid synovial membrane.

Nodular type and diffuse perivascular lymphoid cell infiltrates in rheumatoid synovial membranes from 72 patients were examined under the electron microscope. Attempts were made to describe the ultrastructural relations of the cells examined and to classify the different types of cell-to-cell contracts between them. Members of a complex series, composed of gradually differentiating forms of cell contacts beginning from simple membrane adherences and interdigitations and gap junctions; minute filamentous intercellular bridges: subsurface confronting cisternae and desmosome-like structures, are described and suggested as function-dependent morphological representatives of sites of cellular interactions.

Arthritis, Rheumatoid↗