Hyponatremic-hypertensive syndrome with extensive and reversible renal defects

Two young children with renal artery stenosis and severe hypertension who presented with the so-called hyponatremic-hypertensive syndrome (HHS), with marked urine and solute loss during the acute phase, are described. Both children also presented with severe high molecular proteinuria, glycosuria, and hypercalciuria, only the first symptom having prompt remission after normalization of blood pressure. In children with renal artery stenosis, HHS is associated with severe proteinuria due to hyperfiltration and more extensive tubular functional alterations. Hyponatremia and acute tubulopathy may mask the presenting clinical picture of renal artery stenosis.     

Severe pulmonary hypertension during pregnancy: mode of delivery and anesthetic management of 15 consecutive cases

BACKGROUND: Available literature on pregnant women with severe pulmonary hypertension (PH) relies mainly on anecdotal case reports and two series only. METHODS: The authors reviewed the charts of all pregnant women with severe PH who were followed up at their institution during the past 10 yr, to assess the multidisciplinary treatment and outcome of these patients. RESULTS: Fifteen pregnancies in 14 women with severe PH were managed during this period: There were 4 cases of idiopathic pulmonary arterial hypertension (PAH), 6 cases of congenital heart disease-associated PAH, 1 case of fenfluramine-associated PAH, 1 case of mixed connective tissue-associated PAH, 1 case of human immunodeficiency virus-associated PAH, and 2 cases of chronic thromboembolic PH. PH presented during pregnancy in 3 patients. Two patients died before delivery at 12 and 23 weeks' gestation. Four patients had vaginal deliveries with regional anesthesia: One died 3 months postpartum, one worsened, and two remained stable. Four had cesarean deliveries during general anesthesia: One died 3 weeks postpartum, one worsened, and two remained stable. Five had cesarean deliveries during low-dose combined spinal-epidural anesthesia: One died 1 week postpartum, and four remained stable. There were two fetal deaths: one related to therapeutic abortion at 21 weeks' gestation and one stillbirth at 36 weeks' gestation followed by the death of the mother 1 week later. CONCLUSIONS: Despite the most modern treatment efforts, the maternal mortality was 36%. Scheduled cesarean delivery during combined spinal-epidural anesthesia seemed to be an attractive approach, but there was no evidence of actual benefit. Therefore, pregnancy must still be discouraged in patients with severe PH.     

Complex Interactions Between Tutor Performance,Tutorial Group Productivity and the Effectiveness of PBL Units as Perceived by Students

Aim: Tutor performance and tutorial group productivity interact with each other in a complex manner. The aim of this study was to investigate how tutor performance, tutorial group productivity and the effectiveness of a PBL unit interact with each other. Three hypotheses were tested: (1) Does the tutor performance score differ across different levels of group productivity? (2) Does the group productivity score differ across different levels of tutor performance? and (3) Is the learning effectiveness score of a PBL unit related to tutor performance and group productivity? Method: Students rated the tutor performance, the tutorial group productivity and the effectiveness of the PBL unit. In total 287 unique tutors were involved and were categorized as having a relatively low, average or relatively high score on tutor performance. This was also done for the group productivity score. For each combination, average effectiveness score were computed. Furthermore, partial correlation coefficients were computed. Results: The results demonstrated that the average tutor performance score was higher if the productivity score was higher (hypothesis 1). The results also demonstrated that the average productivity score was higher if the tutor performance score was higher (hypothesis 2). Furthermore it was found that the effectiveness score was higher if the productivity score was higher. The effectiveness score was also higher if the tutor score was higher. The results furthermore demonstrated that the correlation coefficient between tutor performance and effectiveness of the PBL unit is 0.01 (n.s.) if the correlation between the two variables was controlled for group productivity (was 0.36). In addition, the correlation coefficient between group productivity and effectiveness became 0.39 if the correlation between these two variables was controlled for tutor performance (was 0.51) (hypothesis 3). Conclusion: It is concluded that tutor performance differs across different levels of group productivity and that the group productivity score differs across different levels of tutor performance. In addition, it is concluded that both group productivity and the tutor’s performance have an impact on the effectiveness of a PBL unit, although the correlation between group productivity and effectiveness is higher than the correlation between tutor performance and effectiveness. This finding illustrates the importance of the group’s productivity in PBL and the tutor’s importance and implies that schools should put more efforts in improving tutorial group functioning as well as in improving a tutor’s performance.     

In vivo effects of isatin on rat platelet eicosanoids

To establish the possible influence of isatin (2,3-dioxo-indole) on the activity of platelets, the effects of isatin on platelet eicosanoid synthesis were studied in rats. Different doses (12.5-50 mg/kg) of isatin were injected intraperitoneally (i.p.) and the effects on the arachidonate cascade of isolated platelets were investigated. Cells were labeled with [(14)C]arachidonic acid, then the eicosanoids were separated with overpressure thin-layer chromatography and were quantitatively determined with a liquid scintillation analyzer. The lipoxygenase pathway was significantly inhibited by isatin (50 mg/kg) treatment and also the overall activity of the arachidonate cascade was diminished; however, the cyclooxygenase system was significantly stimulated. A 50-mg/kg i.p. dose of isatin significantly increased the production of vasoconstrictor cyclooxygenase metabolites. Among the vasodilator cyclooxygenase products, the synthesis of PGE2 and PGD2 were significantly decreased while that of 12-hydroxyheptadecatrienoic acid (HHT) increased upon isatin (50 mg/kg) administration. Our results provide further evidence on the peripheral actions of isatin and suggest that this endogenous indole may induce significant changes in the production of blood platelet arachidonic acid metabolites, which are important regulatory substances, thus isatin may potentially affect an even broader range of functions than was previously assumed.     

Angiogenesis in ischaemic and hypertrophic hearts induced by long-term bradycardia

Angiogenesis and improved left ventricular function as a consequence of long-term bradycardia were first demonstrated in normal hearts, either electrically paced (rabbits, pigs) or treated with a selective sinus blocking drug alinidine (rats). Here we review the evidence that chronic heart rate reduction can have similar effects in the heart with compromised vascular supply, due to either hypertensive or haemodynamic overload hypertrophy (rats, rabbits) or ischaemic damage (rats, rabbits, pigs). Bradycardia induced over several weeks increased capillarity in all hypertrophied hearts, and in border and remote left ventricular myocardium of infarcted hearts. In some, but not all cases, coronary blood flow was improved by heart rate reduction, suggesting enlargement of the resistance vasculature in some circumstances. Cardiac or left ventricular function indices, which were depressed by hypertrophy or ischaemic damage, were preserved or even enhanced by chronic heart rate reduction. The expansion of the capillary bed in the vascularly compromised heart induced by bradycardia may be stimulated by mechanical stretch of the endothelium and/or VEGF activated by chamber dilation and myocyte stretch. The increased number of capillaries and more homogeneous distribution of capillary perfusion would support the better pump function, even in the absence of higher coronary flow. The beneficial impact of chronic heart rate reduction on myocardial angiogenesis and function in cardiac hypertrophy and infarction may be major factor in the success of beta-blockers in treatment of human heart failure. Correspondence to: Dr. M.D. Brown, School of Sport and Exercise Sciences, University of Birmingham, Birmingham B 15 2TT, UK. Tel: +44-121-4144268; Fax: +44-121-4144121; E-mail: m.d.brown@bham.ac.uk     

Novel genetic structure associated with an extended-spectrum beta-lactamase blaVEB gene in a Providencia stuartii clinical isolate from Algeria

A ceftazidime-resistant Providencia stuartii isolate from Algeria harbored a ca. 160-kb conjugative plasmid that contained a truncated bla(VEB-1b) gene flanked by three 135-bp repeated elements. This work gives further evidence of the worldwide spread of bla(VEB) genes that are associated with genetic structures other than class 1 integrons.