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Biomedical subjects

B McLaughlin

Publications and source records attributed to B McLaughlin.

At least 55 records · Page 3Linked to original sources

Bovine and human pineal glands contain substantial quantities of endothelial cell stimulating angiogenic factor.

Using a quantitative assay the amount of a low Mr endothelial cell stimulating angiogenesis factor (ESAF) has been determined in human pineal glands and bovine brain, retina, pineal gland, liver and kidney. Pineal glands contain approximately ten times as much ESAF as the retina or grey and white matter from the cerebral cortex and a hundred times as much as highly vascular tissues such as liver and kidney. The relevance of these findings to the highly vascular nature of the pineal gland is discussed.

Angiogenesis Inducing Agents↗

Increased procollagenase activating angiogenic factor in the vitreous humour of oxygen treated kittens.

Previous studies have demonstrated an increase in a low molecular weight angiogenic factor (ESAF) present in the retinae of kittens with oxygen induced retinopathy. The present paper describes differences in the quantity of ESAF extracted from the vitreous humour of control and oxygen treated animals and proposes a mechanism for the induction of intravitreal neovascularisation.

Angiogenesis Inducing Agents↗

Treatment of nongonococcal urethritis with ciprofloxacin.

A randomized, double-blind study was performed in 225 men with nongonococcal urethritis or postgonococcal urethritis, in which the efficacy of ciprofloxacin (750 mg twice daily for seven days) was compared with that of doxycycline (100 mg twice daily for seven days). Of the 145 evaluable patients completing three weeks or more of follow-up or reaching an end point, 74 patients received doxycycline and 71 received ciprofloxacin. Chlamydia trachomatis and mixed infections with Ureaplasma urealyticum were more frequent in the cip, ofloxacin group, but the differences were not significant. The overall cure rates were similar for the two regimens (52.1 percent for ciprofloxacin and 60.8 percent for doxycycline; p greater than 0.3). However, in patients with chlamydial infections alone, ciprofloxacin was significantly less effective than doxycycline (45.5 percent versus 75 percent; p = 0.04). In patients with U. urealyticum infections alone, there was a more favorable trend in the ciprofloxacin group (69.2 percent versus 45 percent; p = 0.12). In patients whose culture results were negative, the responses were very similar (60.9 percent for ciprofloxacin and 64.3 percent for doxycycline). Both drugs were well tolerated; side effects, which were mostly gastrointestinal in nature, were mild.

Adult↗

Epiphyseal growth plate cartilage and chondrocytes in mineralising cultures produce a low molecular mass angiogenic procollagenase activator.

We have investigated one aspect of the biochemical control of angiogenesis in the mammalian growth plate. This is the first report of an angiogenic compound from normal growing skeletal tissue. The active agent was indistinguishable from ESAF (endothelial cell-stimulating angiogenic factor), previously identified from tumour, retina and synovial fluid. 1. Using a procollagenase activation assay, ESAF was detected in low molecular weight extracts of growth plate cartilage from two species (foetal calf and young rabbit). ESAF content declined with increasing age of the foetal calf growth plate cartilage. 2. Rabbit growth plate chondrocytes in high density culture also produced ESAF 24-48 h after calcification of the culture. Inhibition of alkaline phosphatase in these cultures reduced the stimulation of ESAF production. These findings suggest that ESAF production occurs as a stage in chondrocyte differentiation which is linked with the onset of matrix calcification. A model is proposed for the control of angiogenesis in the growth plate.

Angiogenesis Inducing Agents↗

Assessment of serologic markers for Epstein-Barr virus.

Antibody responses to early antigen (EA) and viral capsid antigen (VCA) were analyzed in 48 proven cases of Epstein-Barr Virus infection and in 48 age- and sex-matched healthy controls to establish optimal cutoff values for diagnosing EBV infection. Predictive values were determined for individual EA and VCA antibody titers and for EA to VCA antibody ratios and the optimal dilution cutoff values for positivity of EA (1:20), VCA (1:640), and EA to VCA (0:031) were selected. When evaluated on a subset of 10 VCA IgM positive cases and 35 negative controls, the three selected cutoff values identified as infections nine of 10, four of 10, and 10 of 10 of the cases and one of 35, none of 35, and one of 35 of the controls, respectively. When evaluated individually on 22 cases of suspected EBV infection who were heterophile antibody-negative and presented with symptoms compatible with EBV infection, an equal number of VCA IgM-positive and negative cases were identified as EBV infections. Overall, the cutoffs EA, VCA, and ratio identified 19 of 22 (86.4%), 14 of 22 (63.6%), and 18 of 22 (81.8%), respectively, and all cases could be identified using combinations of these values. Although these serologic values may be used with some accuracy, until more definitive markers are described a combination of heterophile responses, lymphocyte analysis, clinical symptoms, and serologic cutoff values should be used to assess the role of EBV in patient evaluation.

Adult↗

Age-related differences in granulocyte chemotaxis and degranulation.

In the present study we have demonstrated that human peripheral blood granulocytes from elderly subjects exhibit reduced chemotaxis and degranulation in response to stimulation with fMet-Leu-Phe. Cyclic AMP levels in non-stimulated cells were not significantly different (mean +/- SEM): 4.8 +/- 0.6 and 3.9 +/- 0.4 pmol/10(7) cells for young and elderly respectively. Stimulation with fMet-Leu-Phe (5 X 10(-7) mol/l) for 30s induced the production of cyclic AMP: 8.4 +/- 0.5 and 6.7 +/- 0.3 pmol/10(7) cells for young and elderly. These findings, together with those previously published by us, suggest that cyclic AMP production and cellular functions which this molecule participates in are reduced in cells from elderly individuals.

Adolescent↗

Isolation and characteristics of small intestinal lamina propria cells from normal and nematode (Nippostrongylus brasiliensis)-infected rats.

Intestinal lamina propria (LP) cells were isolated from normal or nematode (Nippostrongylus brasiliensis)-infected rats. At certain times after infection (days 11-17), viable cell recoveries from infected rats were lower, whereas at other times (days 20-50), they were significantly greater than those from normal rats. The frequencies of lymphocytes, plasma cells, eosinophils, mast cells and macrophages from LP differed between normal and infected rats, and the histamine content did also. However, spontaneous 3H-uridine and 3H-thymidine incorporation and the number of cells with cytoplasmic immunoglobulin were similar. LP cells from normal rats were unresponsive to the mitogens phytohemagglutinin, concanavalin A and pokeweed. 125I-deoxyuridine-radiolabeled LP lymphoblasts from normal rats were widely distributed in recipients 22-24 h after transfer and showed no selective predilection to return to the intestine. The isolation procedure can be used to study intestinal LP cells from normal or diseased animals.

Animals↗

Potentiating effect of heparin in the activation of procollagenase by a low-Mr angiogenesis factor.

A low-Mr freely dialysable endothelial cell-stimulating angiogenesis factor (ESAF) from conditioned medium of a mouse lymphoma cell line has previously been shown to activate latent skin fibroblast procollagenase. Activation comparable with the maximum that can be achieved with trypsin is obtained with chemically undetectable amounts of the factor. We now show that when even smaller amounts of ESAF are used heparin is able to potentiate its action in this system. The relationship between this activity and the mechanism of angiogenesis, which is itself potentiated by heparin, is discussed.

Angiogenesis Inducing Agents↗

Activation of a procollagenase by low-molecular-weight angiogenesis factor.

Avascular tumours have the ability to establish a blood supply for themselves by secreting a humoral factor which stimulates their host's endothelial cells to proliferate and to migrate towards the tumour source. The mechanism of action of such a humoral angiogenesis factor is more than that of an endothelial-cell growth factor since it requires an oriented migration of cells towards the tumour. We report here the activation of pure skin-fibroblast procollagenase by a low-molecular-weight angiogenesis factor capable of stimulating endothelial-cell growth in vitro. The activation was observed when either Type I or III collagen was used as substrate. It is suggested that at least one function of angiogenesis factor is to promote limited degradation of the connective tissue through which it passes causing channeling in the matrix along which stimulated endothelial cells may migrate.

Angiogenesis Inducing Agents↗

Nosocomial septicemia due to multiply antibiotic-resistant Staphylococcus epidermidis.

Thirteen episodes of Staphylococcus epidermidis sepsis occurred over a 20-month period in 11 patients receiving general surgical and medical care. These episodes were characterized by fever, toxicity, multiple positive blood cultures, and uniformly colonized intravascular catheters. An additional 16 patients had possible sepsis. Four associated deaths occurred; all three patients autopsied had multiple pulmonary abscesses in which gram-positive cocci were profusely present. In individual patients, prolonged episodes of septicemia were confirmed by multiple blood culture isolates of S. epidermidis, identical in antibiotic resistance pattern, phage type, and biotype. A prominent feature of the S. epidermidis isolates was resistance to many commonly used antimicrobial agents. Case-control studies and review of laboratory records indicated a significant association between multiply resistant S. epidermidis blood isolates and prolonged hospitalization and parenteral hyperalimentation. Most of these patients were hospitalized in the intensive care unit; nose and hand cultures taken from the personnel showed frequent carriage of multiply resistant S. epidermidis Staphylococcus epidermidis associated with intravascular devices may produce life-threatening bloodstream infections.

Adult↗