Search PubMed⌕ Search

Biomedical subjects

E Cohen

Publications and source records attributed to E Cohen.

At least 253 records · Page 14Linked to original sources
PubMed1988

Evaluation of conventional therapy versus cyclosporine A in Behçet's syndrome.

When ocular structures are affected in Behçet's syndrome, a rapid loss of vision has been the rule regardless of the type of treatment--corticosteroids, Leukeran, Imuran, colchicine. The objectives of the present study were to compare, in a masked manner, conventional treatment (corticosteroids/Leukeran) to treatment with CsA. Forty patients suffering from Behçet's syndrome with active ocular inflammatory reactions were included in the study. These were randomly assigned to conventional or CsA regimens and were regularly examined by a multidisciplinary group of physicians. The unmasked internist modulated the treatment and recorded systemic manifestations. The masked ophthalmologists recorded the ocular findings without knowledge of the assigned type of treatment. An analysis of the results 3 years after initiation of the study shows that CsA is more effective than conventional therapy in decreasing the active ocular inflammatory processes and arresting the deterioration of visual acuity. Regarding the extraocular symptoms, however, conventional therapy is superior to CsA, especially for the control of skin lesions and arthritis. Side effects were recorded in a much higher incidence among patients receiving CsA. However, tight and constant control of the CsA dosage as performed in this study has, so far, prevented clinical and biochemical nephrotoxic manifestations in patients assigned to this treatment.

Adrenal Cortex Hormones↗
PubMed1988

Ciliogenesis and centriole formation in the mouse embryonic nervous system. An ultrastructural analysis.

Serial ultrathin sections were used to study the formation of the primary cilium and the centriolar apparatus, basal body, and centriole in the neuroepithelial primordial cell of the embryonic nervous system in the mouse. At the end of mitosis, the centrioles seem to migrate toward the ventricular process of the neuroepithelial cell, near the ventricular surface. One of these centrioles, the nearest to the ventricular surface, begins to mature to form a basal body, since its tip is capped by a vesicle probably originating in the cytoplasm. This vesicle fuses with the plasmalemma and the cilium growth by the centrifugal extension of the 9 sets of microtubule doublets. These 9 sets invade the thick base of the cilium which is initially capped by a ball-shaped tip with the appearance of a mushroom cilium. The secondary extension of 7, then 5, and finally 2 sets of microtubule doublets contribute to form the tip of the mature cilium, which is associated with a mature centriolar apparatus formed by a basal body and a centriole. Centriologenesis occurs before mitosis and is concomitant with the progressive resorption of the cilium. The daughter centriole, or procentriole, begins to take form near the tips of fibrils that extend perpendicularly and at a short distance from the wall of the parent centriole. Osmiophilic material accumulates around these fibrils, and gives rise to the microtubules of the mature daughter centriole. These centrioles formed by a centriolar process are further engaged in mitosis, after the total resorption of the cilium. This pattern of development suggests that in the primordial cells of the embryonic nervous system, centriologenesis and ciliogenesis are 2 independent phenomena.

Animals↗
PubMed1987

In situ appearance of the cold-stable microtubules in the growing axons of the tectal plate of mouse investigated immunocytochemically after polyethyleneglycol (PEG) embedding.

Tubulin immunostaining of semi-thin sections after polyethylene glycol embedding was used in the tectal plate of the embryonic mouse at 10 days postmating to analyze the effects of cold treatment on the microtubules of the different cell types seen at this stage. Three sets of microtubules are observed. In the radially oriented bipolar columnar cells, dense bundles of microtubules are present in the ventricular processes between the cell nucleus and the ventricular surface. In the mitotic cells, located just at the surface of the ventricle, microtubules are among condensed chromosomal figures. In the apical region, the intermediate zone, tangentially oriented axonal profiles contain dense bundles of microtubules among tangentially oriented young neurons. Cold treatment does not modify the organization of the cells. However, it depolymerizes whole cytoplasmic and mitotic microtubules of the bipolar cells and a large number of microtubules in the growing axons. In the axonal profiles, the cold-stable fraction of microtubules displays the appearance of short fragments. Some of these are regularly organized, suggesting that they could be the remnants of the same individual microtubule. These fragments are approximately 1 micron long and seem to represent nearly 10% of the total microtubules in the axons. These cold-stable fragments might fulfill a function in the axon analogous to the microtubule organizing centers in the perikaryon and their presence can explain some properties of the growing axons suggested by previous studies on the guidance of neurites and growth cones as well as on the growth of isolated axons.

Animals↗
PubMed1987

Proteinase-induced formation of focal tight junctions in HT 29 adenocarcinoma cells does not require extracellular calcium.

The human adenocarcinoma cell line HT 29 grows virtually without tight junctions, but the formation of focal tight junctions can be induced by brief treatment with proteinases. The freeze-fracture morphology of proteinase-induced tight junctions is not affected by treatment with EGTA or EDTA over a period of 30 min. The induction of tight junctions by trypsin or pronase can proceed in the presence of 3 mM EGTA or EDTA. Neither the formation nor the structure and complexity of the induced tight junctions is affected by the chelators. It follows that no extracellular divalent cations are required for the induced formation and the structural integrity of focal tight junctions in HT 29 cells.

Adenocarcinoma↗
PubMed1987

Heterogeneity of cold-stable and cold-labile tubulin in axon- and soma-enriched portions of the adult mouse brain.

Microtubules from the optic nerve (axonal tubulin) and lateral geniculate nucleus (cell tubulin) were separated by cold treatment and the cold-soluble fraction was purified in the presence of Taxol. Isoforms of cold-stable and cold-soluble tubulin were resolved by the use of high-resolution isoelectric focusing. The cold-soluble fraction of axonal tubulin has only 14 of the 20 isotypes seen in the same fraction of cell tubulin. The two cold-stable fractions have 20 isotypes but axonal tubulin has a specific pattern of isotypes 1, 2 and 5. Cold-stable fractions of both axonal and cell tubulin display the existence of an intensely stained alpha-isotype, isotype 7, which seems associated with the property of cold stability. Our results highly favor the hypothesis of a physiological role of the heterogeneity of tubulin in neuronal microtubules.

Animals↗
PubMed1987

Natural antibodies to human lymphocytes and erythrocytes in the serum of Orcinus orca killer whale.

The existence of naturally occurring heterophile antibodies to antigenic determinants on human blood cell membranes has long been known. It has been shown that the serum of Orcinus orca (Killer whale) does contain similar antibody. Absorption techniques in concert with either microagglutination or complement-dependent microcytotoxicity assays revealed at least three antibody specificities erythrocyte (RBC), B-lymphocyte and T-lymphocyte. Human erythrocyte specificity has been separated from other mammalian RBC specificity, and higher microagglutination titers and/or scores were observed with human group A RBC's than with group B,O, or AB. Tests run at 4 degrees, 20 degrees and 37 degrees C). Higher microcytotoxicity and microagglutination activity was demonstrated with B versus T lymphocytes. It is hoped that the characterization of the antigenic specificity of these heterophile agglutinins will prove to be useful as a biological reagent-tool which may be applied to the identification of a new receptor on human lymphocytes and/or erythrocytes. Also, if isolated, these agglutinins could be useful in the study of the occurrence and presence of specific receptors on cell membranes and give insight as to how these receptors change in health, disease and malignancy.

Agglutinins↗
PubMed1987

Ultrastructural analysis of primary cilium in the embryonic nervous tissue of mouse.

In the embryonic nervous system, the morphology and spatial organization of the ciliary apparatus in the primordial cells, the neuroepithelial bipolar cells, has been analysed from frontal and horizontal ultrathin sections. Projecting into the ventricular fluid, the primary cilium is located just at the interface between the ventricular fluid and the cytoplasm of these cells. Always associated with a basal body and a centriole, their structural components are nine microtubule doublets equally spaced around the luminal cylinder without central doublet. The cilium is short with a thick base displaying a reduced ciliary necklace and a 9 + 0 pattern. In its tip, the pattern decreases from 7 + 0 to 2 + 0. The basal body differs from the basal body of the motil cilium by internal and external sheets interconnecting triplets from base to apex, the constant existence of an accessory basal foot and the scarcity of a ciliary rootlet. All these characteristics suggest that in the neuroepithelial bipolar cells the ciliary apparatus is a rigid, polarized and transient structure probably important in the possible exchange between the ventricular fluid and the developing nervous system.

Animals↗
PubMed1987

Collagenase activity in colonic mucosa during inflammatory bowel disease.

A simple test for collagenase activity was performed on colonic mucosa specimens of 35 patients with inflammatory bowel disease, 7 patients with carcinoma of the colon, 3 with benign polyps, and 34 normal subjects. Increased collagenase activity was present in 94.2% of the specimens taken from the inflamed mucosa and 71.4% of those obtained from colonic carcinoma, as compared to 8.8% of the control group.

Clinical Enzyme Tests↗
PubMed1987

[Anesthesia for the surgery of the thoracic and thoraco-abdominal aorta].

Haemodynamic monitoring, anaesthetic technique and perioperative management were reported for a series of 317 consecutive patients who underwent graft replacement of descending thoracic or thoracoabdominal aortic aneurysms at the Baylor College of Medicine, Houston (Texas) between january 1979 and june 1982. The surgical technique used was aortic clamping without shunt. The anaesthetic technique combined high dose fentanyl (50-100 micrograms X kg-1), oxygen ventilation, pancuronium bromide and vascular filing. The patients were monitored by Swan-Ganz catheters. The systemic blood pressure increased by 8% during the clamping of the aorta in spite of the use of sodium nitroprussiate, whereas the systemic vascular resistances did not increase significantly. The cardiac output increased by 19%, whereas the heart rate remained stable. After unclamping, the systemic blood pressure did not decrease significantly, whereas the systemic vascular resistances fell by 20%; the cardiac output increased by 64%, whereas the heart rate remained stable. The 30-day mortality was 10% (32 patients). Four of them died during surgery. The postoperative morbidity included 33 cases of paraplegia and paraparesis, 31 cases of renal insufficiency and 28 cases of postoperative pulmonary complications. The prevention of the consequences of aortic clamping and the management of the hypoxaemia occurring during one lung anaesthesia are discussed.

Adult↗
PubMed1987

In vivo 1-aminocyclopropane-1-carboxylate synthase activity in internodes of deepwater rice : enhancement by submergence and low oxygen levels.

Inasmuch as the activity of 1-aminocyclopropane-1-carboxylate (ACC) synthase cannot be measured in homogenates of deepwater rice internodes (Oryza sativa L.), we have employed an in vivo assay to determine the activity of this enzyme. This assay is based on the accumulation of ACC in tissue kept under N(2). Submergence of whole plants or stem sections containing the uppermost, developing internode enhances the in vivo activity of ACC synthase in the stem. This stimulation of in vivo ACC-synthase activity is especially pronounced in the region of the internode containing the intercalary meristem and the elongation zone above it. Enhancement of in vivo ACC-synthase activity is evident after 2 hours of submergence and shows a peak after 4 hours. Reduced levels of atmospheric O(2), which promote ethylene synthesis and growth in internodes of deepwater rice, also enhance the in vivo activity of ACC synthase. Our results are consistent with the hypothesis that induction of ACC-synthase activity at low partial O(2) pressures is among the first biochemical events leading to internodal growth in deepwater rice.

Journal Article↗
PubMed1986

Accumulation of (3H)glycine by cone bipolar neurons in the cat retina.

Cone bipolar neurons in the cat retina were studied in serial sections prepared as electron microscope autoradiograms following intravitreal injection of (3H)glycine. The goal was to learn whether the cone bipolar types that accumulate glycine correspond to the types thought on other grounds to be inhibitory. About half of the cone bipolars in a given patch of retina showed specific accumulation of silver grains. The specificity of accumulation was similar to that shown by glycine-accumulating amacrines. All of the cone bipolars arborizing in sublamina b accumulated glycine but none of the cone bipolars arborizing in sublamina a did so. The types of cone bipolars accumulating glycine did not match the types thought to be inhibitory. Cone bipolar types CBb1 and CBb2 both form gap junctions with the glycine-accumulating AII amacrine, thus raising the possibility that glycine might accumulate in these cone bipolars by diffusion from the AII cell or vice versa. Thus it is logically impossible to tell which of these three cells contains a high-affinity uptake mechanism for glycine and consequently which of the three might actually use glycine as a neurotransmitter.

Animals↗
PubMed1986

Evidence for and partial characterization of three major and three minor chromatographic forms of human neutrophil myeloperoxidase.

Myeloperoxidase (MPO) is an enzyme found in the azurophil granules of neutrophils. Cation-exchange chromatography on carboxymethyl-cellulose previously has been used to demonstrate the heterogeneity of the peroxidase enzymes isolated from human neutrophils. In this study, fast protein liquid chromatography (FPLC) was used to separate and purify three major (I, II, and III) and three minor (IIa, IIIa, IIIb) forms of MPO from isolated neutrophil granules. Purity was confirmed by polyacrylamide gel electrophoresis in the presence of cetyltrimethylammonium bromide (CETAB-PAGE), by crossed immunoelectrophoresis, and by spectral characteristics. All three major forms were indistinguishable by immunodiffusion against rabbit antiserum, scanning spectrophotometry, and amino acid composition. They differed in their elution from a cation-exchange resin, inhibition by 3-amino-1,2,4-triazole, migration rate in CETAB-PAGE, and subunit molecular weight. Subunit molecular weight was examined using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). All three major forms appeared to consist of heavy (H), intermediate (M), and light (L) peptides. The M peptide appeared to be derived from the H subunit. All L subunits exhibited a molecular weight of 14,500. The molecular weights for the H subunits varied, and were 60,000, 59,000, and 57,000 for MPO I, II, and III, respectively. The molecular weights for the M peptides were 44,100, 43,000, and 42,000 for MPO I, II, and III, respectively. The treatment of neutrophils, granules, and extracts with protease inhibitors and sodium azide did not block the appearance of three major forms of MPO. Thus, neither protease activity nor MPO autooxidation during extraction and purification procedures is responsible for the appearance of multiple chromatographic forms of MPO derived from human neutrophils.

Amino Acids↗