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Biomedical subjects

E Wilson

Publications and source records attributed to E Wilson.

At least 145 records · Page 8Linked to original sources
PubMed1987

Immunocytochemical localization of protein kinase C in resting and activated human neutrophils.

An immunocytochemical method was used to determine possible changes in the subcellular distribution of protein kinase C (PKC) in human neutrophils in response to opsonized latex beads and zymosan. While in resting cells most of the PKC immunoreactivity was localized in the cytoplasm, a redistribution of PKC to the plasma and phagosomal membranes was observed in cells treated with latex beads or zymosan for 5-20 min, suggesting a participation of PKC in endocytosis.

Adult↗
PubMed1987

The relationship of tubal infertility to barrier method and oral contraceptive use.

We studied past contraceptive use in 283 nulliparous infertile women who had a diagnosis of tubal adhesions or occlusion and in 3833 women admitted for delivery at seven collaborating hospitals from 1981 to 1983. The relative risk of tubal infertility associated with barrier contraceptive use or oral contraceptive use was calculated using multivariate logistic regression to control for confounding by region, age, religion, education, smoking, number of sexual partners, time since menarche, and use of other contraceptive methods. Women who had ever used barrier methods of contraception were at a significantly decreased risk of tubal infertility (relative risk = 0.6; 95% confidence limits, 0.5 and 0.8). When type of barrier method used for the longest time was evaluated, those who used the diaphragm or condoms plus spermicides were at lower risk than those who used condoms or spermicides alone. Overall, past use of oral contraceptives neither increased nor decreased a woman's risk of tubal infertility, but there was evidence that the association between oral contraceptives and tubal infertility may vary by the amount of estrogen and type of progestogen in the oral contraceptive used. We conclude that contraceptive users who use barrier methods that combine both a mechanical and chemical barrier, such as diaphragms, cervical caps, and condoms plus spermicides, have the clearest protection against tubal damage.

Adult↗
PubMed1987

The association between smoking and female infertility as influenced by cause of the infertility.

Smoking histories were compared in 901 women with infertility of different types and 1264 women admitted for delivery at seven collaborating hospitals. The relative risk for infertility associated with cigarette smoking prior to the infertility diagnosis for nulliparous cases or first live birth for controls was calculated using a multivariate logistic-regression model to control for potential confounding factors, including center, age, religion, education, number of sexual partners, and contraceptive use. The adjusted risk for infertility attributed primarily to cervical factor (n = 96) was 1.7 (P = 0.04), to tubal disease unrelated to endometriosis (n = 225) was 1.6 (P = 0.009), to ovulatory factor (n = 389) was 1.0 (not significant [NS]), and to endometriosis (n = 191) was 0.9 (NS). The authors conclude that cigarette smoking is significantly associated only with certain types of primary female infertility.

Adult↗
PubMed1987

Three-dimensional structure of the bifunctional enzyme N-(5'-phosphoribosyl)anthranilate isomerase-indole-3-glycerol-phosphate synthase from Escherichia coli.

N-(5'-Phosphoribosyl)anthranilate isomerase-indole-3-glycerol-phosphate synthase from Escherichia coli is a monomeric bifunctional enzyme of Mr 49,500 that catalyzes two sequential reactions in the biosynthesis of tryptophan. The three-dimensional structure of the enzyme has been determined at 2.8-A resolution by x-ray crystallography. The two catalytic activities reside on distinct functional domains of similar folding, that of an eightfold parallel beta-barrel with alpha-helices on the outside connecting the beta-strands. Both active sites were located with an iodinated substrate analogue and found to be in depressions on the surface of the domains created by the outward-curving loops between the carboxyl termini of the beta-sheet strands and the subsequent alpha-helices. They do not face each other, making "channeling" of the substrate between active sites virtually impossible. Despite the structural similarity of the two domains, no significant sequence homology was found when topologically equivalent residues were compared.

Aldose-Ketose Isomerases↗
PubMed1987

Platelet-derived growth factor stimulates phagocytosis and blocks agonist-induced activation of the neutrophil oxidative burst: a possible cellular mechanism to protect against oxygen radical damage.

The effect of platelet-derived growth factor (PDGF) on agonist-induced activation of the superoxide-generating oxidative burst in human neutrophils was tested. PDGF had no effect on the resting level of superoxide generation but inhibited both the rate and the extent of fMet-Leu-Phe-stimulated superoxide production in a dose-dependent manner. The concentration required to inhibit the response by 50% was 95 +/- 26 pM (n = 10). PDGF also blocked activation by other receptor-mediated agonists such as the complement protein C5a and opsonized zymosan, but not by phorbol myristate acetate or arachidonate, both of which may act at postreceptor sites. The growth factor, however, had no effect on the binding of fMet-Leu-Phe to its receptor. PDGF in concentrations that blocked the oxidative burst stimulated phagocytosis of opsonized latex particles. Thus, PDGF functions as a heterologous "down-regulator" of receptor-mediated activation of the neutrophil oxidative burst and an activator of phagocytosis. A model for a feedback regulatory loop between platelets and neutrophils is proposed.

Blood Platelets↗
PubMed1987

Determinants of mitochondrial O2 dependence in kidney.

The O2 dependence of mitochondrial cytochromes was studied in suspensions of isolated rat kidney cells to examine the determinants of renal mitochondrial function. Direct spectroscopy of the oxidation of cytochromes c + c1, a + a3, and b561 + b566 showed that oxidation-reduction changes of the entire electron transport chain occur over the same range of O2 concentrations; this suggests that the mitochondrial cytochromes function as a single unit in response to O2 changes. Half-maximal oxidation (P50 value) of cytochrome c + c1 in intact cells was 3.6 microM but was only 0.45 microM in isolated renal cortex mitochondria under state 3 conditions. This is consistent with the existence of a substantial O2 concentration gradient from the extracellular space to the region around the mitochondria under hypoxic conditions. Comparison with results for digitonin-treated cells under state 3 conditions indicates that the distribution of mitochondria within the cellular structure is an important determinant of the cellular O2 dependence. In addition, the mitochondrial O2 dependence varies as a function of cellular respiration rate. Stimulation of the O2 consumption with either a protonophore, carbonyl cyanide p-trifluoromethoxyphenylhydrazone, or a sodium ionophore, nystatin, increased the P50 value. Conversely, inhibition of ATP consumption by Na+-K+-ATPase with ouabain, or inhibition of mitochondrial electron transport with antimycin A, decreased the P50 value. Thus the O2 concentration required for mitochondrial function in the kidney is affected by mitochondrial distribution within the cell as well as by the functional demands imposed on the cell.

Animals↗
PubMed1987

Congenital ocular motor apraxia without head thrusts.

Congenital ocular motor apraxia is a distinctive disorder that may present initially as apparent cortical blindness, because of the patient's inability to make saccadic eye movements to fixate targets moving in the horizontal plane. Affected children develop a characteristic compensatory head thrust that allows them to fixate and allows the physician to make the diagnosis. Two patients, initially thought to be blind because of a lack of fix or following responses in the horizontal plane, are reported. Although head thrusts were not present because of inadequate head control, the diagnosis of congenital ocular motor apraxia was made because of other diagnostic features. The cases emphasize the need to consider congenital ocular motor apraxia in any child thought to be cortically blind.

Apraxias↗
PubMed1986

Inhibition of the oxidative burst in human neutrophils by sphingoid long-chain bases. Role of protein kinase C in activation of the burst.

The neutrophil oxidative burst is characterized by increased cellular O2 consumption due to the activation of a membrane-associated superoxide-generating NADPH-oxidase. The response is triggered by a variety of stimuli, including opsonized zymosan, formylmethionylleucinephenylalanine (FMLP), arachidonate, short-chain diacylglycerols, and phorbol myristate acetate (PMA). We herein demonstrate that incubation of cells with sphinganine or sphingosine blocks or reverses activation by these agonists. The inhibition is reversible, does not affect cell viability, and does not affect another complex cell function, phagocytosis. Inhibitory concentrations of sphinganine did not significantly affect cytoplasmic calcium levels or FMLP-generated calcium transients. Structural requirements for inhibition of the oxidative burst include a long aliphatic chain and an amino-containing head-group, and there is modest specificity for the native (erythro) isomer of sphinganine. Inhibition involves stimulus-induced activation mechanisms rather than a direct effect on the NADPH oxidase, since sphinganine did not inhibit NADPH-dependent superoxide generation in isolated membranes containing the active enzyme. Activation by FMLP, diacylglycerol, PMA, opsonized zymosan, and arachidonate was blocked by the same concentrations of sphinganine, indicating that these agonists share a common inhibited step. Three lines of evidence indicate that this step involves protein kinase C. First, in a micelle system and in platelets, long-chain bases are inhibitors of this enzyme (Hannun, Y., Loomis, C., Merrill, A., and Bell, R. M. (1986) J. Biol. Chem. 261, 12604-12609). Second, sphinganine blocks PMA-stimulated incorporation of 32PO4 into neutrophil proteins. Third, sphinganine inhibits the binding of [3H]phorbol dibutyrate to its cellular receptor, known to be protein kinase C. We suggest that long-chain bases function as physiologic modulators of cellular regulatory pathways involving protein kinase C.

Arachidonic Acid↗
PubMed1986

The relation of endometriosis to menstrual characteristics, smoking, and exercise.

We compared menstrual characteristics and constitutional factors in 268 white women with primary infertility due to endometriosis and in 3,794 white women admitted for delivery at seven collaborating hospitals from 1981 to 1983. Adjusting for confounding factors, including location, age, religion, and education, women with short-cycle lengths (less than or equal to 27 days) and longer flow (greater than or equal to one week) had more than double the risk for endometriosis compared with women with longer cycle lengths and shorter duration of flow. There was a trend for increasing risk for endometriosis to be associated with increasing menstrual pain. Adjusting for these menstrual characteristics, we found decreased risk for endometriosis associated with smoking or exercise that was largely confined to women who began either habit at an early age and were heavier smokers or more strenuous exercisers. We conclude that risk for endometriosis may relate to menstrual factors that predispose to greater pelvic contamination with menstrual products and to constitutional factors that influence endogenous hormonal levels.

Adolescent↗
PubMed1986

Granulocytic sarcoma with an indolent course and destructive skeletal disease. Tumor characterization with immunologic markers, electron microscopy, cytochemistry, and cytogenetic studies.

A 6-year-old girl with a granulocytic sarcoma (GS) of the left maxillary sinus that followed a uniquely indolent clinical course (3.5 years) and was associated with highly destructive skeletal disease is described. The tumor cells demonstrated an unusual hematogenous "homing" preference for bone and soft tissue sites. Tumor cell characterization with immunologic markers, electron microscopy, cytochemistry, and cytogenetic studies revealed that the tumor cells expressed OKM1 and MMA (Leu-M1), but not HLA-DR, B-, or T-cell markers. The cells were nonspecific esterase- and myeloperoxidase-positive, had ultrastructural features of promyelocytes, and were clonal. The laboratory characterization of the tumor cells in this clinically unusual case of GS illustrates the utility of monoclonal antibodies, applied in conjunction with cytochemistry and ultrastructural analysis, in establishing the specific diagnosis, cell lineage, and maturational stage of this tumor.

Antibodies, Monoclonal↗
PubMed1986

NADH dehydrogenase from bovine neutrophil membranes. Purification and properties.

A membrane-associated NADH dehydrogenase from beef neutrophils was purified to homogeneity, using detergent (cholate plus Triton X-100) extraction and chromatography on DEAE-Sepharose CL-6B, agarose-hexane-NAD, and hydroxylapatite. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed an apparent subunit molecular weight of 17,500, but the enzyme was highly aggregated (Mr greater than 450,000) in nondenaturing gels containing 0.1% Triton X-100. The protein band in nondenaturing gels was also stained for activity using NADH and nitro blue tetrazolium. The enzyme showed greatest electron acceptor activity with ferricyanide (100%), followed by cytochrome c (3.5%), dichloroindophenol (2.7%), and cytochrome b5 (0.34%). No activity was seen with oxygen. The Km values for NADH and ferricyanide were 18 and 9.5 microM, respectively, and NAD+ was a weak competitive inhibitor (Ki = 118 microM). No activity was seen with NADPH. No effects were seen with mitochondrial respiratory inhibitors such as azide, cyanide, or rotenone, but p-chloromercuribenzoate was strongly inhibitory and N-ethylmaleimide was weakly inhibitory. No free flavin was detectable in enzyme preparations. Based upon kinetic, physical, and inhibition properties, this NADH dehydrogenase differs from those previously described in microsomes and erythrocyte plasma membrane.

Animals↗
PubMed1985

Photoaffinity labeling of an antimycin-binding site in Rhodopseudomonas sphaeroides.

Tritium-labeled 3-azidosalicyl-N-(n-octadecyl)amide was synthesized and used as a photoaffinity probe for the antimycin-binding site in both purified ubiquinone-cytochrome b-c1 oxidoreductase and chromatophore vesicles from the photosynthetic bacterium Rhodopseudomonas sphaeroides. In both systems, a prominently labeled protein had a molecular weight of 11,000. Binding to this protein was inhibited by preincubation of the reaction mixture with antimycin prior to addition of the radioactive analog and subsequent irradiation. The antimycin analog, 3-azidosalicyl-N-(n-octadecyl)amide, inhibited succinate-cytochrome c reductase activity in chromatophore vesicles by 50% at a concentration of 150 nmols/mg of protein.

Affinity Labels↗
PubMed1985

Tubal infertility and the intrauterine device.

To study the association between intrauterine devices (IUDs) and pelvic inflammatory disease, we compared contraceptive histories in 4185 while women--283 nulliparous women with primary tubal infertility, 69 women with secondary tubal infertility, and 3833 women admitted for delivery at seven collaborating hospitals from 1981 to 1983. The relative risk of tubal infertility associated with IUD use was calculated by means of multivariate logistic regression to control for confounding factors, including region, year of menarche, religion, education, smoking, and reported number of sexual partners. The adjusted risk of primary tubal infertility associated with any IUD use before a first live birth was 2.0 (95 per cent confidence limits, 1.5 to 2.6) relative to nonuse. Users of the Dalkon Shield had an adjusted risk of 3.3 (1.7 to 6.1), users of the Lippes Loop or Saf-T-Coil had a risk of 2.9 (1.7 to 5.2), and users of copper IUDs had a risk of 1.6 (1.1 to 2.4). Women who reported having only one sexual partner had no increased risk of primary tubal infertility associated with IUD use. The adjusted risk of secondary tubal infertility associated with use of a copper IUD after a first live birth was not statistically significant (1.5; 95 per cent confidence limits, 0.8 to 3.0), whereas the risk from similar use of noncopper devices was significant (2.8; 1.3 to 5.9). We conclude that tubal infertility is associated with IUD use, but less so with copper IUDs.

Adult↗
PubMed1985

Conventional and high-frequency ventilation in dogs with bronchopleural fistula.

Seven anesthetized dogs with bronchopleural fistulas were subjected to a sequence of continuous positive-pressure ventilation (CPPV), volume-controlled high-frequency positive-pressure ventilation (HFPPV), and high-frequency vibratory ventilation (HFVV). Adequate short-term ventilation and oxygenation were possible with all three ventilatory modes. During HFPPV and HFVV, PaCO2 was unchanged, but hypercarbia developed during CPPV. PaO2 decreased during each mode of ventilation, but HFPPV maintained PaO2 at a sufficient and constant level during the 30-min test period. HFPPV was the most efficient technique with respect to delivery of minute ventilation, the relation between fistula flow and delivered ventilation, and maintenance of both ventilation and oxygenation.

Animals↗
PubMed1985

Apolipoprotein E associated with astrocytic glia of the central nervous system and with nonmyelinating glia of the peripheral nervous system.

The plasma protein apolipoprotein (apo) E is an important determinant of lipid transport and metabolism in mammals. In the present study, immunocytochemistry has been used to identify apo E in specific cells of the central and peripheral nervous systems of the rat. Light microscopic examination revealed that all astrocytes, including specialized astrocytic cells (Bergmann glia of the cerebellum, tanycytes of the third ventricle, pituicytes of the neurohypophysis, and Müller cells of the retina), possessed significant concentrations of apo E. In all of the major subdivisions of the central nervous system, the perinuclear region of astrocytic cells, as well as their cell processes that end on basement membranes at either the pial surface or along blood vessels, were found to be rich in apo E. Extracellular apo E was present along many of these same surfaces. The impression that apo E is secreted by astrocytic cells was confirmed by electron microscopic immunocytochemical studies, which demonstrated the presence of apo E in the Golgi apparatus. Apo E was not present in neurons, oligodendroglia, microglia, ependymal cells, and choroidal cells. In the peripheral nervous system, apo E was present within the glia surrounding sensory and motor neurons; satellite cells of the dorsal root ganglia and superior cervical sympathetic ganglion as well as the enteric glia of the intestinal ganglia were reactive. Apo E was also present within the non-myelinating Schwann cells but not within the myelinating Schwann cells of peripheral nerves. These results suggest that apo E has an important, previously unsuspected role in the physiology of nervous tissue.

Animals↗