Antidiabetic and haematological effect of aqueous extract of stem bark of Afzelia africana (Smith) on streptozotocin-induced diabetic Wistar rats

Objective

To investigate the antidiabetic properties of aqueous extract of stem bark of Afzelia africana (A. africana) and its beneficial effect on haematological parameters in streptozotocin induced diabetic rats.

Methods

A total of 30 rats including 24 diabetic and 6 normal rats were used for this study. Diabetes was induced in male Wistar rats by intraperitoneal injection of streptozotocin. After being confirmed diabetic, animals were orally treated with distilled water or extracts at 100 or 200 mg/kg body weight daily for 10 days. The haematological parameters including red blood and white blood cells and their functional indices were evaluated in diabetic treated groups compared with the controls.

Results

The extract significantly reduced the blood glucose levels while the best result was obtained at 200 mg/kg body weight. The feed and water intake in diabetic rats were significantly reduced while weight loss was minimized at both dosages. Similarly, the levels of red blood, white blood cells and their functional indices were significantly improved after extract administration at both doses.

Conclusions

It can be concluded that the aqueous extract of bark of A. africana possesses antihyperglycemic properties. In addition, the extract can prevent various complications of diabetes and improve some haematological parameters. Further experimental investigation is needed to exploit its relevant therapeutic effect to substantiate its ethnomedicinal usage.     

Bias formulas for sensitivity analysis of unmeasured confounding for general outcomes, treatments, and confounders

Uncontrolled confounding in observational studies gives rise to biased effect estimates. Sensitivity analysis techniques can be useful in assessing the magnitude of these biases. In this paper, we use the potential outcomes framework to derive a general class of sensitivity-analysis formulas for outcomes, treatments, and measured and unmeasured confounding variables that may be categorical or continuous. We give results for additive, risk-ratio and odds-ratio scales. We show that these results encompass a number of more specific sensitivity-analysis methods in the statistics and epidemiology literature. The applicability, usefulness, and limits of the bias-adjustment formulas are discussed. We illustrate the sensitivity-analysis techniques that follow from our results by applying them to 3 different studies. The bias formulas are particularly simple and easy to use in settings in which the unmeasured confounding variable is binary with constant effect on the outcome across treatment levels.     

Apoptosis: a novel therapeutic tool?

Apoptosis is a genetically programmed cell death mechanism that appears to occur in all multicellular organisms. It is a normal process that serves to maintain cellular homeostasis. However, in many diseases there is a disruption in the equilibrium between cell proliferation and cell death that contributes directly to the disease. In these cases, a possible therapeutic intervention would be to restore the skewed equilibrium by pushing it in the desired direction through the use of pharmacological agents or genetic approaches. These observations have instigated substantial research in the field of apoptosis, resulting in an increasingly detailed analysis of the molecular mechanisms and the sequence of events that occur in this cell death pathway. In addition, by trying to understand this pathway, several potential therapeutic agents have arisen from those used in chemo-, radio-, and cytokine therapy. While these agents have been relatively successful, it is rare that their effect is complete. Thus, the search continues for a strategy to conquer those cells that are resistant to these regimens. Genetic approaches are novel and have been shown to be quite successful in several in vitro and animal models. They also tend to have low toxicity. It is believed that using a more traditional front-line approach of therapy, supplemented by appropriate genetic intervention, will allow substantial increases in the efficacy of treatment, while at the same time introducing little or no additional toxicity.     

Validity of police contacts as a performance indicator for the public mental health care system in Amsterdam: an open cohort study

Purpose

The Public Mental Health Care (PMHC) system is a network of public services and care- and support institutions financed from public funds. Performance indicators based on the registration of police contacts could be a reliable and useful source of information for the stakeholders of the PMHC system to monitor performance. This study aimed to provide evidence on the validity of using police contacts as a performance indicator to assess the continuity of care in the PMHC system.

Methods

Data on services received, police contacts and detention periods of 1928 people that entered the PMHC system in the city of Amsterdam were collected over a period of 51 months. Continuity of care was defined as receiving more than 90 days of uninterrupted service. The associations between police contacts and continuity were analyzed with multilevel Poisson and multivariate linear regression modeling.

Results

Clients had on average 2.12 police contacts per person-year. Clients with police contacts were younger, more often single, male, and more often diagnosed with psychiatric or substance abuse disorders than clients without police contacts. Incidence rates of police contacts were significantly lower for clients receiving continuous care than for clients receiving discontinuous care. The number of police contacts of clients receiving PMHC coordination per month was found to be a significant predictor of the percentage of clients in continuous care.

Conclusion

The number of police contacts of clients can be used as a performance indicator for an urban PMHC system to evaluate the continuity of care in the PMHC system.

     

Neue Drähte und deren Kraftabgabe-Konsequenzen für die kieferorthopädische Therapie

Zusammenfassung Nivellierungsbögen aus verseilten Stahldrähten wurden mit Nickel-Titanium-Drähten der neuen Generation, ausgezeichnet durch Formgedächtnis, Superelastizität und exzellentes Rückstellvermögen, verglichen. Die im Biegeversuch ermittelten Werte wurden statistisch aufbereitet und ergaben eine lineare Kraftweg-Kennlinie der verseilten Stahldrähte. Die Nickel-Titanium-Drähte zeigten aber eine deutliche Abweichung von der Linearität mit kurviger Verlaufsform. Neben der atypischen Kraftweg-Kennlinie mit einer konstanten Kraftabgabe im Mittel der Kurve gaben diese Drähte, unabhängig vom Aktivierungsgrad (das heißt unabhängig davon, ob die Stufe zwischen den Brackets 1 oder 4 mm betrug), dieselbe Kraft ab. Je größer die Aktivierung zwischen den Brackets war, desto länger stellte sich der Bereich der konstanten Kraftabgabe-die Superelastizität-im Diagramm dar. Daher eignen sich die Drähe für große Niveauunterschiede oder Deflektionen. Bei geringer Aktivierung verläuft die Kennlinie sehr steil und annähernd linear. In diesen Fällen ist verseilten Stahldrähten aufgrund ihrer kleineren Federrate und Flexibilität der Vorzug zu geben.

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Summary Levelling arches made of stainless-steel wires were compared with nickel-titanium wires of the new generation which are distinguished by their shape memory, superelasticity and their excellent spring-back. The data received from a bending test have been analysed statistically and revealed a linear unloading curve of the twisted stainless-steel wires. The nickel-titanium wires, however, showed a clear deviation form the linearity with a curviform course. Besides the unusual unloading curve with a constant force mechanism in the middle range of deactivation the wires give off the same amount of force irrespective of the degree of activation (that is to say, regardless whether the level difference between the brackets amounts to 1 or to 4 mm). The diagram shows that the greater the activity between the brackets, the longer the period of superelasticity. Therefore the nickel-titanium wires are suited for large level differences or deflections. At a low activation rate the characteristic line takes a very steep and almost linear deactivation curve. In these cases twisted stainless steal wires should be preferred because of their lower load deflection rate and flexibility.

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Résumé Les arcs de nivelage de fils d'acier tressés ont été comparés avec les fils nickel-titane de la nouvelle génération, se distinguant par leur mémoire de forme, superélasticité et capacité excellente de rappel. Les valeurs relevées au cours de l'essai de pliage ont été enregistrées statistiquement et ont montré une caractéristique linéaire du tracé de force des fils d'acier tressés. Les fils nickel-titane ont cependant montré une déviation significative en présentant non une linéarité mais un tracé curviligne. A côté de leur caractéristique atypique de leur tracé de force avec un dégagement constant de force au centre de la courbe, ces fils ont produit la même force, indépendamment, du degré d'activation (c.-à-d., indépendamment du fait que l'espace entre les brackets fut de 1 ou 4 mm). Plus l'activation était grande entre les brackets, plus la zone du dégagement de la force constante-la superélasticité, paraissait longue sur le diagramme. C'est pourquoi ces fils sont indiqués pour de fortes différences de niveau ou déflexions importantes. En cas d'activation peu considérable, le tracé est très raide et presque linéaire. Dans ces cas, la préférence doit être accordée aux fils d'acier tressés, en raison de leur force élastique et flexibilité inférieures.

     

Die Entwicklung des Parodontiums nach Zahnkeimtransplantationen im Rahmen der kieferorthopädischen Behandlung

Zusammenfassung Durch Tierversuche an jungen Beagle-Hunden konnte die normale Entwicklung des Parodontiums nach Zahnkeimtransplantationen histologisch nachgewiesen werden. Die klinisch-röntgenologischen Untersuchungen zeigten keine pathologischen Befunde im Parodontiumbereich nach Zahnkeimtransplantationen beim Menschen. Die transplantierten Zähne können wie die anderen kieferorthopädisch bewegt werden. In diesem Beitrag wird auf die häufigsten Indikationen von Zahnkeimtransplantationen von Molaren, Prämolaren und Eckzähnen hingewiesen.

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Summary The normal development of the periodontal structures was confirmed histologically on young Beagle-dogs following tooth-germ transplants. In humans, clinical and radiographic examinations revealed no pathology of the periodontium following transplantation of tooth germs. The grafted teeth could be moved orthodontically in the same way as any other teeth. No precautions need to be taken. This paper describes the most common indications for transplanting the tooth-germs of canines, bicuspids and molars.

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Résumé Dans les expérimentations animales chez de jeunes chiens-Beagles, on a prouvé que les structures parodontales sont normalement développées après la transplantation de germes dentaires. Les examens cliniques et radiologiques chez de jeunes sujets d'espèce humaine n'ont pas montré de résultats pathologiques au niveau du parodonte après la greffe de germes dentaires. Les dents transplantées peuvent être déplacées orthodontiquement comme les autres dents sans mesures spéciales. Dans cet article, on a donné les indications concernant les greffes des germes de molaires, prémolaires et canines.