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Biomedical subjects

B German

Publications and source records attributed to B German.

16 recordsLinked to original sources
PubMed1999

Increased neonatal platelet deposition on subendothelium under flow conditions: the role of plasma von Willebrand factor.

In vitro platelet function of umbilical cord blood and neonatal peripheral vein blood from full-term newborns was compared with that of adults. Citrated whole blood was subjected to shear stress (1300 s(-1)) on subendothelial extracellular matrix (ECM)-coated wells in a cone and plate(let) analyzer. Adhered platelets on the ECM were quantitated by image analyzer. Both umbilical cord and neonatal peripheral blood platelets demonstrated more extensive adhesion than adult platelets, and similar aggregate formation on ECM. The ability of neonatal platelets to form aggregates on ECM was confirmed by scanning electron microscopy. Similar activation of neonatal and adult platelets after subjection to shear stress, in the suspension phase, was established by flow cytometry, which showed an increase in fibrinogen binding and a decrease in glycoprotein Ib expression on platelet membrane. The difference in adhesion rates between neonatal and adult platelets was preserved even when the hematocrit level of the neonatal blood was adjusted to that of adults. Reconstitution of neonatal or adult platelet-rich plasma with autologous or heterologous red packed cells yielded no change in adhesion and aggregation. When von Willebrand factor-covered plates were used to prevent deposition of plasma von Willebrand factor on the surface, no difference in platelet adhesion was seen between neonatal and adult blood. In conventional aggregometry assay, the response to ristocetin of washed platelets of either neonatal or adult source was higher on addition of plasma from neonates than from adults. Our data suggest that the extensive neonatal platelet deposition on ECM is mediated by plasma von Willebrand factor, which is known to be more multimerized and, therefore, more active in neonates than in adults. This mechanism may provide balanced primary hemostasis in neonates despite the platelet hyporeactivity to agonists without application of shear stress.

Adult↗
PubMed1998

A simple clinical test for differentiating physiological from pathological head lag in full-term newborn infants.

UNLABELLED: This prospective study was designed to assess the value of a simple clinical test, a "feeding test", on the outcome of head lag among term neonates. Of 5718 infants who were examined before their morning meal, 67 had moderate to severe head lag in the absence of predisposing risk factors for head lag. Fifteen minutes following feeding, 62 infants (92%) showed an improvement in or disappearance of head lag with concomitant rise in serum glucose. All of these infants had normal psychomotor development on follow up. In 4 infants in whom no improvement occurred after feeding, an underlying pathological cause for head lag was subsequently diagnosed. CONCLUSION: Use of the feeding test as a screening procedure in apparently healthy newborns with head lag may rule out pathological conditions in over 90% of the cases.

Blood Glucose↗
PubMed1998

Dietary polyunsaturated fatty acids decrease anti-dsDNA and anti-cardiolipin antibodies production in idiotype induced mouse model of systemic lupus erythematosus.

OBJECTIVE: To examine the effect of diets with different polyunsaturated fatty acid contents, including linseed oil which contains 70% omega-3 fatty acids, on autoantibody production in idiotype induced mouse model of systemic lupus erythematosus (SLE). METHODS: Five different fats were fed to mice with induced SLE and antibody titers to anti-DNA and anti-cardiolipin were determined and histological examination of kidneys were carried out. RESULTS: SLE mice fed linseed oil showed lower titers of antibodies to DNA and to cardiolipin and less severe kidney damage than mice fed other diets, including fish oil. CONCLUSION: Use of linseed oil may attenuate the severity of SLE and this diet may be recommended for other auto-immune diseases as well.

Animals↗
PubMed1997

Iodine and hypothyroidism in neonates with congenital heart disease.

AIM: To evaluate the influence of the intravenous injection of iodine during cardiac catheterisation, and of topical iodine antiseptics during surgical procedures, on thyroid function in full term neonates. METHODS: Twenty one full term infants with major cardiac anomalies who survived for more than a month were studied. Thyroxine and thyrotropin concentrations were measured (by radioimmunoassay) before each procedure, 24 hours after the procedure, and every week thereafter until the age of 1 month or until normal. Thyroxine values less than 64.4 nmol/l were considered low, while thyrotropin values greater than 30 mU/l were considered high. RESULTS: Thyroid function tests before iodine exposure were within normal limits in all infants. Following catheterisation or surgery six infants had raised thyrotropin concentrations; three had low thyroxine concentrations. Two of those infants were treated with L-thyroxine. CONCLUSION: Iodine exposure during cardiac catheterisation or surgery may induce transient hypothyroidism in term infants.

Anti-Infective Agents, Local↗
PubMed1988

Differential effects of docosahexaenoic acid and eicosapentaenoic acid on suppression of lipoxygenase pathway in peritoneal macrophages.

Docosahexaenoic acid (DHA) or eicosapentaenoic acid (EPA) was facilely incorporated into phospholipids of mouse peritoneal macrophages following incubation with pure fatty acids complexed to bovine serum albumin. Following stimulation with calcium ionophore A23187, the DHA-enriched cells synthesized significantly smaller amounts of leukotriene C4 and leukotriene B4 compared to control or EPA-enriched cells. The EPA-enriched cells synthesized lower amounts of leukotriene C4 and leukotriene B4 compared to control cells. The stimulated macrophages utilized endogenously released arachidonic acid for leukotriene B4 and leukotriene C4 synthesis. Exogenous arachidonic acid increased the formation of 12-hydroxyeicosatetraenoic acid (12-HETE) and 15-HETE and macrophages enriched with DHA or EPA produced similar amounts of 12-HETE and 15-HETE compared to control cells. These studies demonstrated that the synthesis of leukotriene C4, leukotriene B4 and HETE in macrophages is differentially affected by DHA and EPA.

Animals↗
PubMed1985

Uricase from fish liver: isolation and some properties.

The uricase (urate: oxygen oxidoreducase EC.1.7.3.3) activities in livers from rainbow trout, mackerel, lake trout, catfish, shark and tilapia were 1000, 1180, 920, 630, 490 and 420 units (n moles uric acid oxidized mg-1 protein min-1) per gram liver, respectively. The enzyme from lake trout was purified twenty fold by ammonium sulfate precipitation, protamine sulfate treatment and Sephacryl S-200 column chromatography. SDS-polyacrylamide gel-electrophoresis indicated an oligomeric enzyme containing subunits of 32,500 daltons. The pH optimum was 8.8 but the enzyme had a relatively broad pH activity profile between pH 7.0-9.5. Apparent Km and Vmax values of 80 microM and greater than 1000 was obtained for the trout liver enzyme.

Animals↗
PubMed1984

Biosynthesis of prostanoids, tissue fatty acid composition and thrombotic parameters in rats fed diets enriched with docosahexaenoic (22:6n3) or eicosapentaenoic (20:5n3) acids.

The objective of this experiment was to elucidate the effect(s) of eicosapentaenoic (20:5n3) vs docosahexaenoic (22:6n3) acid on prostaglandin biosynthesis and related thrombotic parameters. Diets were formulated to contain oils absent in (control) or enriched with either 20:5n3) EPA) or 22:6n3 (DHA). The diets were fed to rats for three weeks and the following evaluated: 1) bleeding time; 2) blood viscosity; 3) platelet aggregation; 4) tissue fatty acids; 5) serum thromboxane (TXB2), aortic prostacyclin (6-keto) ad 6) arachidonic acid conversion to eicosanoids by lung microsomes. There were no significant differences between treatments for bleeding time, red blood cell viscosity or platelet aggregation. In EPA fed rats 20:5n3 increased significantly in platelet and aorta phospholipids. In platelets and aorta 20:4n6 was slightly decreased in EPA and DHA animals. Platelet 22:6n3 levels were not altered by treatment, but 22:6n3 increased in the aorta of EPA and DHA fed rats. Similar changes were noted in lung and liver fatty acid composition. Serum TXB2 levels were significantly decreased only in the EPA vs control group. No differences were noted for aortic 6-keto levels or in the amount of hydroxy fatty acids, PGE, TXB2 or PGF2 alpha produced by lung microsomes. While fish oils have been shown to alter hematologic parameters in humans this study suggests that the rat is not similarly affected. Furthermore, it is evident that in the rat, 20:5n3 and not 22:6n3 is responsible for the alterations in platelet prostaglandin biosynthesis; however, these observations may not be directly applicable to other species.

Animals↗
PubMed1983

Prostaglandins and thromboxane: tert.-butyldimethylsilyl ethers as derivatives for their analyses by gas chromatography-mass spectrometry-selected ion monitoring.

tert.-Butyldimethylsilyl ethers of eighteen prostaglandins (PGs) and thromboxane have been analyzed by combined packed-column or fused-silica capillary gas chromatography-mass spectrometry (GC-MS). Except for thromboxane B2 and PGs of the 3 series the [M - 57] ion, the loss from the molecular ion of the tert.-butyl radical, is generally the major peak in the spectra of PGs. This high abundance of large fragments provides suitable criteria for the employment of these derivatives in GC-MS selected ion monitoring for rapid quantity estimation of PGs from biological samples. PGs from rat stomach fundus were rapidly quantitated in a single chromatogram using this procedure.

Animals↗