Biomedical subjects
Publications and source records attributed to K Wenzel.
Processes for total quality management, redesigning of patient care delivery and differentiated practice in nursing were developed and implemented simultaneously on two nursing units. This article describes the activities of the steering team and three work groups through the first nine months of implementation.
By using the non-isotopic single-strand conformation polymorphism (SSCP) technique to analyse products of the polymerase chain reaction (PCR), we detected a 561-adenine to cytosine substitution resulting in an amino acid exchange from serine to arginine at position 128 of the E-selectin gene. If this amino acid substitution has an effect on the adhesion of blood cells to the endothelium, the polymorphism could be of interest with respect to association studies in a number of pathological conditions, such as cardiovascular diseases.
Adhesion molecules like the members of the selectin family participate in the interaction between leukocytes and the endothelium. They are also involved in the pathogenesis of atherosclerotic processes. To contribute to the analysis of the genetic background of atherosclerosis we searched for DNA polymorphisms in the genes encoding adhesion molecules especially E-selectin which seems to be expressed only in activated endothelium. An adenine to cytosine substitution for cDNA position 561 resulting in an amino acid exchange from serine to arginine (position 128) was detected in the epidermal growth factor like domain. A significantly higher mutation frequency (P = 0.02) was observed in 97 patients aged 50 years or less with angiographically proven severe atherosclerosis (allele frequency of arginine 0.155) compared with an unselected population (allele frequency of arginine 0.088) as well as in 40 patients aged 40 years or less (allele frequency of arginine 0.21, P = 0.0025). These data suggest that the 128-serine/arginine polymorphism is associated with a higher risk for early severe atherosclerosis.
OBJECTIVE: This report presents initial findings on the reliability and validity of a new retrospective measure of child abuse and neglect, the Childhood Trauma Questionnaire. METHOD: Two hundred eighty-six drug- or alcohol-dependent patients were given the Childhood Trauma Questionnaire as part of a larger test battery, and 40 of these patients were given the questionnaire again after an interval of 2 to 6 months. Sixty-eight of the patients were also given a structured interview for child abuse and neglect, the Childhood Trauma Interview, that was developed by the authors. RESULTS: Principal-components analysis of responses on the Childhood Trauma Questionnaire yielded four rotated orthogonal factors: physical and emotional abuse, emotional neglect, sexual abuse, and physical neglect. Cronbach's alpha for the factors ranged from 0.79 to 0.94, indicating high internal consistency. The Childhood Trauma Questionnaire also demonstrated good test-retest reliability over a 2- to 6-month interval (intraclass correlation = 0.88), as well as convergence with the Childhood Trauma Interview, indicating that patients' reports of child abuse and neglect based on the Childhood Trauma Questionnaire were highly stable, both over time and across type of instruments. CONCLUSIONS: These findings provide strong initial support for the reliability and validity of the Childhood Trauma Questionnaire.
1. Numerous compounds and changes in physical state functions shift the membrane potential of vascular smooth muscle to more negative values. The consequence is a vasodilatation because Ca2+ channels are closed. K+ channel opening frequently causes the hyperpolarization. 2. Acidification of the blood substitute solution and a fall in O2 partial pressure dilate arterial vessels. Acidosis is associated with a rise in K+ permeability and a simultaneous fall in Na+ permeability. Prostacyclin has a 20-30% share, and EDHF a 70-80% share, in hypoxic vasodilatation. Experiments with iloprost (PGI2 analogue) confirmed the K+ channel opening properties of this drug. A voltage-dependent K+ channel and a Ca(2+)-activated K+ channel, via the influence of cA-PK or cG-PK, are responsible for the hyperpolarization with iloprost and with oxygen deficiency. 3. Cicletanine and ajoene cause a concentration-dependent membrane hyperpolarization and are potent vasodilators. A cicletanine concentration, which is attained by the dosage given to patients, is sufficient to produce these effects. Ajoene exerts a hyperpolarizing and vasodilating influence even in a concentration which may occur in the extracellular space by the administration of a single garlic clove. 4. The stationary activation curve 'developed force vs. membrane potential' satisfactorily explains the effects of K+ channel openers. The tight electromechanical coupling expressed by this curve comprises a 50% vasorelaxation for a 2.5 mV hyperpolarization. In the linear part of the curve, the coupling ratio is 5.1 mV/g. 5. In the vascular smooth muscle, vasorelaxation can be evoked by membrane hyperpolarization which is linked to a simultaneous increase in K+ outward current and 42K+ efflux. In the case of substances whose influence is solely or partially receptor-mediated, cyclic nucleotides may be involved in vasorelaxation. Since cyclic nucleotides also hyperpolarize through an increase in K+ conductance, the resulting dilatation often cannot be divided into its single components. Therefore, it is sensible not to give the term "K+ channel opener" too fine a definition. The term should be applied to all substances and changes in physical states which predominantly increase the open probability of K+ channels finally via a conformational change in the cell membrane. For example, giving an acidic blood substitute solution (acidosis) is an intervention opening K+ channels. Which K+ channel and which single channel conductance is concerned in a particular case, and which 'mediator' may participate, become secondary questions.
The simultaneous i.v. administration of equimolar doses of bretylium and hexylsalicylic acid results in an increase in plasma area under the curve value of both substances in comparison with their separate administration. The higher plasma levels of both compounds were associated with a reduced renal excretion and an increased biliary elimination. However, the increase in biliary excretion did not compensate for the reduced elimination of bretylium and hexylsalicylic acid via the kidney. The results presented in this paper give further evidence that ion-pairing in-vivo may result in altered pharmacokinetics of drugs particularly due to changes in biliary or renal excretion.
Whereas the chemotactic peptide, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMet-Leu-Phe), induced NADPH-oxidase-catalyzed superoxide (O2-) formation in human neutrophils, purine and pyrimidine nucleotides per se did not stimulate NADPH oxidase but enhanced O2- formation induced by submaximally and maximally stimulatory concentrations of fMet-Leu-Phe up to fivefold. On the other hand, FMet-Leu-Phe primed neutrophils to generate O2- upon exposure to nucleotides. At a concentration of 100 microM, purine nucleotides enhanced O2- formation in the effectiveness order adenosine 5'-O-[3-thio]triphosphate (ATP[gamma S]) greater than ITP greater than guanosine 5'-O-[3-thio]triphosphate (GTP[gamma S]) greater than ATP = adenosine 5'-O-[2-thio]triphosphate (Sp-diastereomer) = GTP = guanosine 5'-O-[2-thio]diphosphate (GDP[beta S] = ADP greater than adenosine 5'-[beta, gamma-imido]triphosphate = adenosine 5'-O-[2-thio]triphosphate] (Rp-diastereomer). Pyrimidine nucleotides stimulated fMet-Leu-Phe-induced O2- formation in the effectiveness order uridine 5'-O-[3-thio]triphosphate (UTP[gamma S]) = UTP greater than CTP. Uracil (UDP[beta S]) = uridine 5'-O[2-thio]triphosphate (Rp-diastereomer) (Rp)-UTP[beta S]) = UTP greater than CTP. Uracil nucleotides were similarly effective potentiators of O2- formation as the corresponding adenine nucleotides. GDP[beta S] and UDP[beta S] synergistically enhanced the stimulatory effects of ATP[gamma S], GTP[gamma S] and UTP[gamma S]. Purine and pyrimidine nucleotides did not induce degranulation in neutrophils but potentiated fMet-Leu-Phe-induced release of beta-glucuronidase with similar nucleotide specificities as for O2- formation. In contrast, nucleotides per se induced aggregation of neutrophils. Treatment with pertussis toxin prevented aggregation induced by both nucleotides and fMet-Leu-Phe. Our results suggest that purine and pyrimidine nucleotides act via nucleotide receptors, the nucleotide specificity of which is different from nucleotide receptors in other cell types. Neutrophil nucleotide receptors are coupled to guanine-nucleotide-binding proteins. As nucleotides are released from cells under physiological and pathological conditions, they may play roles as intercellular signal molecules in neutrophil activation.
A simple HPLC method for the determination of sulfur is described. Sulfur is extracted from foodstuffs with petroleum ether, separated by means of HPLC and measured at 263 or 254 nm.
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The influence of chemical composition and formulation on the absorption of radiophosphorus-labelled trichlorphon, butonate and dimethoate was investigated with isolated strips of bovine skin. Other factors studied were polarity of the solvent, concentration of pesticide, and effect of surface-active agents and dimethyl sulphoxide. Absorption experiments were also carried out on cattle and sheep, and the results were compared with those of the in vitro tests.
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