Evaluation and assessment of new disposable strip for determination of plasma potassium concentration.

Overall laboratory reproducibility for the Ames Seralyzer and plasma potassium test strips was less than 4% within the plasma reference range; and linearity extended from 2.1 to 10.2 mmol/l. Neither bilirubin nor lipaemia interfered in the analysis and selectivity for potassium over sodium was 450:1. Laboratory comparison with automated flame photometry and an indirect ion selective electrode showed a Seralyzer bias of +0.10 (+/- 25D 0.26) and +0.11 (0.27) mmol/l. Against flame photometry, comparison of analyses by six doctors from a coronary care unit and four nurses from a renal dialysis unit showed smaller positive biases (0.06 and 0.02 mmol/l) but substantially larger error ranges (0.43 and 0.55 mmol/l, respectively). Some 49% of the nurses' and 37% of the doctors' results differed from laboratory values by more than 0.2 mmol/l. Potassium test strip results proved acceptably comparable and reproducible when produced by an experienced analyst, but greater variability in clinical hands rendered the system unsuitable for precise monitoring of potassium concentration.     

Effects of instruction by practice assistants on inhaler technique and respiratory symptoms of patients. A controlled randomized videotaped intervention study

BACKGROUND: Many patients with asthma or chronic obstructive pulmonary diseaseuse their medication inhalers incorrectly. General practitioners,pharmacists and other health care providers do not always havethe opportunity to instruct patients in correct inhaler technique. OBJECTIVE: To find out whether the inhaler technique and respiratory symptomsof patients can be improved after instruction by practice assistants. METHODS: Single blind, randomized intervention study in which 48 patientswho had been using a dry powder inhaler for at least one monthtook part. Their inhaler technique was videotaped on two visitswith a two-week interval between visits. The inhaler techniqueon the videos was subsequently scored by two experts on ninecriteria. At both visits the patients completed a questionnaireabout their respiratory symptoms. After the first video, 25patients were randomly chosen to receive instruction from oneof six practice assistants who had followed a one evening courseabout inhaler instruction, and who had been issued an instruction-set. RESULTS: The patients who received instruction had a significantly greaterreduction in number of mistakes at the second visit than thepatients who did not (P = 0.01). The instructed patients alsoreported less dyspnoea at the second visit (P = 0.03). No effectof instruction was found on wheezing, cough and sputum production. CONCLUSION: The inhaler technique of patients can be improved significantlyby the instruction of patients by trained practice assistants,possibly resulting in less dyspnoea. Keywords. Administration-inhalation, obstructive lung diseases, airways symptoms, patient-education, general practice.     

Bovine colostrum immunoglobulin concentrate for cryptosporidiosis in AIDS.

Lactobin-R is a commercial hyperimmune bovine colostrum with potent anticryptosporidial activity. It was administered to a 4 year old child with AIDS and severe diarrhoea associated with cryptosporidiosis. There was significant clinical improvement in the diarrhoea and permanent elimination of the parasite from the gut as assessed through serial jejunal biopsy and stool specimens.     

Translation of the humeral head on the glenoid with passive glenohumeral motion

We have demonstrated that certain passive motions of the glenohumeral joint are reproducibly accompanied by translation of the head of the humerus on the glenoid. We investigated the relationship of these translations to the position of the glenohumeral joint and to applied torques and forces in seven isolated glenohumeral joints from fresh cadavera, using a six-degrees-of-freedom position sensor and a six-axis force and torque transducer. Reproducible and significant translation occurred in an anterior direction with glenohumeral flexion and in a posterior direction with extension. We also observed translation with cross-body movement. The translation occurring with flexion was obligate in that it could not be prevented by the application of an oppositely directed force of thirty to forty newtons. Operative tightening of the posterior portion of the capsule increased the anterior translation on flexion and cross-body movement and caused it to occur earlier in the arc of motion compared with the intact glenohumeral joint. Operative tightening of the posterior part of the capsule also resulted in significant superior translation with flexion of the glenohumeral joint.     

Gentamicin administration via peritoneal dialysis fluid: the risk of ototoxicity.

In a prospective study on 47 patients, 16 mg of gentamicin per two litres dialysate was administered intraperitoneally at every cycle of intermittent peritoneal dialysis, carried out over the course of several days. Serum gentamicin sampling, pure tone audiometry and caloric tests were performed before and during the treatment. The gentamicin levels reached at the end of the thirtieth cycle were observed to be low. In view of this, the risk of acute ototoxicity was considered to be minimal. This was confirmed by the absence of clinical audiometric or vestibulometric evidence of toxicity.     

Effect of smoking on fibronectin production by human amnion and placenta.

Fibronectin production from amnion and placental tissues was evaluated in pregnant woman smokers and nonsmokers in order to examine if there were alterations of fibronectin metabolism in intrauterine tissues. In both amnion and placental tissues, cycloheximide inhibited the fibronectin output indicating that it was being synthesized. Mean fibronectin output by amnion in pregnant woman smokers was significantly lower than that in pregnant woman nonsmokers. In contrast, in the placenta from pregnant woman smokers, the output was significantly higher than that in pregnant woman nonsmokers. The present observations indicate that smoking alters an important biochemical constituent in amnion and placenta, possible leading to some complications.     

Molecular genetic characterization of XRCC4 function

XRCC4 is a generally expressed protein of 334 amino acids that is involved in the repair of DNA double-strand breaks and in V(D)J recombination, but its function is unknown. In this study, we have used a mutational approach and the yeast two-hybrid method to perform an initial characterization of this protein. We show that the XRCC4 protein is located in the nucleus. We also demonstrate that several potential phosphorylation sites are not required for XRCC4 function in a transient V(D)J recombination assay. In addition, we show that XRCC4 forms a homodimer in vivo with the homodimerization domain being located within amino acids 115-204. Finally, we define a core domain of XRCC4 that functions in V(D)J recombination and comprises amino acids 18-204. Potential functions of XRCC4 are discussed.      

Is fecundability associated with month of birth? An analysis of 19th and early 20th century family reconstitution data from The Netherlands

The relationship between fecundability and month of birth was investigated in a cohort of 1526 women who married between 1802 and 1929, using only women whose first marriage occurred before the age of 35 years. On the basis of their time to pregnancy (TTP, calculated as time between wedding and first birth minus gestational length), women were categorized into two groups: fecunds (TTP up to 12 months or prenuptial conceptions, n = 1348) and subfecunds (TTP >18 months, n = 118). By use of logistic regression, cosinor functions with a period of 1 year or 6 months and variable shift and amplitude were fitted through the monthly odds of subfecunds versus fecunds. The best fitting curve was unimodal, with a zenith in September (P = 0.13 for H0: no differences). Exclusion of childless women (n = 36, minimum follow-up 5 years) from the subfecunds led to a similar curve (P < 0.01), while childless women, as compared with fecunds, showed a birth distribution that was best represented with a bimodal curve with zeniths in January and July (P = 0.06). This study provides evidence for the existence of differences in fecundability by month of birth. The cause of this relationship is unclear, but may lie in a melatonin-dependent circannual variability of the quality of the oocyte.      

Monoamine oxidase B(MAO-B) is the major catalyst for 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) oxidation in human brain and other tissues

A new in vitro radiometric method has been developed for the direct assay of the oxidation of 1-methyl-4-phenyl-1,2,3,6-tetrahydrophyridine (MPTP) to its main neurotoxic metabolite 1-methyl-4-phenylpyridinium. This assay has been used to show that the rate of oxidation of MPTP parallels that of phenylethylamine in a range of human and rodent tissues, providing strong evidence that this reaction is predominantly catalysed by monoamine oxidase B (MAO-B). In human brain the reaction was inhibited by selective doses of the MAO-B inhibitor (-)-deprenyl. When dopamine was added to the incubation mixture, products of MPTP oxidation appeared to form a complex with it.     

Variations in strength of vertebrae with age and their relation to osteoporosis

Fourth and fifth lumbar vertebrae were obtained at post mortem examinations of human subjects in the range 26 to 86 years and at the same time specimens were taken from the iliac crests for histological assessment of trabecular density (iliac crest score). After removal of pedicles and spinous processes the vertebrae were compressed in a testing machine to mechanical failure. The following values were obtained; breaking stress (load per unit area at failure), strain (percentage deformation) at failure and relative ash content (ash per unit volume). Strain at failure was independent of the size and strength of the vertebrae. The relative ash content and the iliac crest score were closely correlated. The relative ash content and the breaking stress both declined with increasing age, but the relation between them was not linear since the breaking stress fell more quickly than the ash content. Euler's equation for the buckling stress of a loaded column readily explains how in osteoporosis the reduction of the diameter of the vertical trabeculae and the loss of transverse ties cause loss of strength proportionately greater than the loss of osseous tissue. The results give no reason to suppose that in osteoporosis the quality of the osseous tissue is changed.

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Zusammenfassung Die vierten und fünften Lumbalwirbelknochen wurden von Obduktionen menschlicher Leichen innerhalb der Altersgrenzen von 26 und 86 Jahren gewonnen. Gleichzeitig wurden Proben von der Beckenschaufel entnommen, um Maßstäbe für die Bälkchendichte festzulegen (Beckenschaufelzahl). Nach Entfernung der Ansätze und Dornfortsätze wurden die Wirbelknochen in einer Prüfungsmaschine komprimiert, um mechanisches Versagen zu bestimmen. Folgende Werte wurden erhalten: Bruchbelastung (Gewicht pro Einheitsfläche bei Bruch), Beanspruchung (Prozentsatz von Deformation) bei Bruch und relativer Aschegehalt (Asche pro Einheitsvolumen). Die Beanspruchung bei Bruch war unabhängig von Größe und Stärke der Wirbelknochen. Zwischen dem relativen Aschegehalt und der Beckenschaufelzahl bestand eine enge Verbindung. Der relative Aschegehalt und die Bruchbelastung wurden mit fortschreitendem Alter kleiner, jedoch war die Beziehung zwischen diesen beiden Faktoren nicht linear, da die Bruchbelastung rascher als der Aschegehalt abnahm. MitEulers Gleichung für die Verbiegungsbelastung einer geladenen Säule läßt sich leicht erklären, auf welche Weise bei der Osteoporose die Reduktion des Durchmessers der Wirbeltrabekeln und der Verlust der transversen Verbindungen einen verhältnismäßig größeren Stärkeverlust hervorruft, als durch Verlust von Knochengewebe erklärt werden kann. Die Ergebnisse geben keinen Anlaß zu der Vermutung, daß bei der Osteoporose die Qualität des Knochengewebes eine Veränderung erfährt.

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Résumé Les quatrième et cinquième vertèbres lombaires sont prélevées post-mortem chez des sujets humains, âgés de 26 à 86 ans, et des échantillons de crête iliaque sont collectés simultanément pour établir histologiquement la densité des travées osseuses (index de la crête iliaque). Après avoir enlevé les pédicules et les apophyses épineuses, les vertèbres sont compressées dans une machine pour tester la résistance mécanique. Les valeurs suivantes sont déterminées: force de rupture (en poids par unité de surface au moment de la rupture), effort de rupture (en pourcentage de déformation) et contenu relatif en cendres (en cendres par unité de volume). L'effort de rupture est indépendant de la taille et de la force des vertèbres. Le contenu relatif en cendres et l'index de la crête iliaque sont en rapports étroits. Le contenu relatif en cendres et la force de rupture diminuent en fonction de l'âge, mais ce rapport n'est pas linéaire, car la force de rupture chute plus rapidement que le contenu en cendres. L'équation d'Euler pour une force courbe appliquée à une colonne chargée explique facilement comment, dans l'ostéoporose, la réduction de diamètre des travées verticales et la perte des attaches transversales sont responsables de la perte de force proportionellement plus élevée que la perte de tissu osseux. Les résultats ne permettent pas de supposer que, dans l'ostéoporose, la qualité du tissu osseux est altérée.