Dehydration of a crystal hydrate at subglacial temperatures.

Water is one of the most important substances on our planet. It is ubiquitous in its solid, liquid and vaporous states and all known biological systems depend on its unique chemical and physical properties. Moreover, many materials exist as water adducts, chief among which are crystal hydrates (a specific class of inclusion compound), which usually retain water indefinitely at subambient temperatures.

Horizontal HIV transmission to children of HIV-uninfected mothers: A case series and review of the global literature.

Background: Vertical transmission is the predominant route for acquisition of HIV infection in children, either in utero, intrapartum or postnatally through breast feeding. Less frequently, children may acquire HIV by horizontal transmission. Horizontal transmission may be healthcare-associated (infusion of HIV-contaminated blood products, use of contaminated needles, syringes and medical equipment, or through ingestion of HIV in expressed breastmilk).

A comparison of energetic criteria to probe the stabilizing interaction resulting from a bond path between congested atoms.

Four energetic criteria, all rooted in the partitioning of a molecule into atomic basins based on the properties of the electron density, are compared and correlated with the presence of a bond path between two nonbonded atoms in a series of sterically crowded derivatives of the same tetracyclododecane molecule. It was found that there is no correlation between the selected energetic criteria and the existence of a bond path between the congested atoms, nor with the existence of Ehrenfest force, virial, or Coulomb potential paths between those atoms.

Vesico-ureteric reflux and urinary tract development in the Pax2 1Neu+/- mouse.

Vesico-ureteric reflux (VUR) is a urinary tract abnormality that affects roughly one-third of patients with renal-coloboma syndrome, an autosomal dominant condition caused by a mutation in PAX2. Here, we report that a mouse model with an identical mutation, the Pax2 1Neu+/- mouse, has a 30% incidence of VUR. In VUR, urine flows retrogradely from the bladder to the ureter and is associated with urinary tract infections, hypertension, and renal failure.

Microinjection and electroporation of embryonic kidney explants: an improved method.

Embryonic kidney explants are routinely used to study the molecular regulation of kidney development. One of the major technical challenges has been the need to express transgenes at high levels for prolonged periods of time. Existing protocols derived from work with the chick have used microinjection and electroporation with low voltage and long pulse time.

Overexpression of RET leads to vesicoureteric reflux in mice.

RET, a tyrosine kinase receptor essential for kidney development, has recently been shown to be important for the formation of the urinary tract. When RET is overexpressed in the HoxB7/Ret transgenic mouse, kidneys are small and cystic, and in some of the mice, the ureters are grossly dilated. Here, we report that the observed ureteral dilatation is associated with the urinary tract abnormality vesicoureteric reflux (VUR), in which urine flows retrogradely from the bladder to the ureter.

Smad expression during kidney development.

Signaling by the transforming growth factor (TGF)-beta superfamily is important during kidney development. Here, we describe the spatial and temporal expression patterns of the Smads, the transcription factors that translate TGF- signals into gene expression. RT-PCR data and in situ hybridization analysis showed that the receptor-regulated (R) Smads (Smad1, -2, -3, -5, and -8), the common partner Smad (Smad4), and the inhibitory (I) Smads (Smad6 and -7) were all expressed during mouse kidney development from embryonic day 12 until the end of nephrogenesis at postnatal day 15.

Single-bolus tenecteplase compared with front-loaded alteplase in acute myocardial infarction: the ASSENT-2 double-blind randomised trial.

Background: Bolus fibrinolytic therapy facilitates early efficient institution of reperfusion therapy. Tenecteplase is a genetically engineered variant of alteplase with slower plasma clearance, better fibrin specificity, and high resistance to plasminogen-activator inhibitor-1. We did a double-blind, randomised, controlled trial to assess the efficacy and safety of tenecteplase compared with alteplase.

Antioxidant vitamins and coronary artery disease risk in South African males.

Decreased antioxidant-vitamin nutritional status may increase lipid peroxidation and susceptibility of low-density lipoprotein (LDL) to oxidative modification. The aim of this study was to evaluate the vitamin nutritional status of coronary artery disease (CAD) patients and to assess the risk of CAD related to each individual antioxidant vitamin. The study was performed as a case-control study with 41 patients with angiographically demonstrated CAD and 41 apparently healthy age- and smoking status-matched controls.

A single amino acid substitution in transmembrane helix VI results in overexpression of the human GnRH receptor.

Objective: Construction of constitutively active mutants of the GnRH receptor, a member of the G-protein coupled receptor superfamily, would facilitate investigation of the mechanism of receptor activation.

Design: Point mutations were introduced in the human GnRH receptor in positions corresponding to those which caused constitutive activity in other G-protein coupled receptors. The effects of these mutations on ligand binding, receptor intracellular signaling and receptor expression were determined.

Alanine-261 in intracellular loop III of the human gonadotropin-releasing hormone receptor is crucial for G-protein coupling and receptor internalization.

Gonadotropin-releasing hormone (GnRH) is a decapeptide that regulates reproductive function via binding to the GnRH receptor, which is a G-protein-coupled receptor (GPCR). For several members of this family, the C-terminal domain of intracellular loop III is important in ligand-mediated coupling to G-proteins; mutations in that region can lead to constitutive activity. A specific alanine residue is involved in certain GPCRs, the equivalent of which is Ala-261 in the GnRH receptor.

Efficacy and tolerability of nisoldipine coat-core formulation in the treatment of essential hypertension: The South African Multicenter ANCHOR Study. Ambulatory Nisoldipine Coat-Core Hypertension Outpatient Response (ANCHOR) Investigators.

A double-blind, placebo-controlled, multicenter trial was undertaken to assess the antihypertensive efficacy and tolerability of a controlled-release (Coat-Core [CC] tablet) formulation of the second-generation dihydropyridine calcium channel antagonist, nisoldipine. Of the 208 patients with mild-to-moderate essential hypertension, two were excluded from the main efficacy analysis, and the rest randomized into one of four treatment groups, to receive either placebo, or nisoldipine CC at doses of 10, 20, or 30 mg once daily for 6 weeks, following a 4-week placebo run-in period. Blood pressure measurements (supine, standing, diastolic, and systolic) were taken at trough plasma levels, 24 h after previous dosing at 2-week intervals throughout the study.

Incorporation of an additional glycosylation site enhances expression of functional human gonadotropin-releasing hormone receptor.

Mutation ofN-glycosylation sites in the mouse gonadotropin-releasing hormone receptor was previously shown to impair its expression in COS-1 cells. We therefore investigated the effects of adding an extra glycosylation site to the human gonadotropin-releasing hormone receptor, as a means for increasing its expression. Covalent labeling of the mutant receptor expressed in COS-1 cells with a gonadotropin-releasing hormone (GnRH) photoreactive analog demonstrated a shift in apparent molecular weight, indicating that the new site was in fact glycosylated.

Post-exercise time-course analysis of ST segment and T wave changes: an important contribution to the role of stress electrocardiography in aircrew.

Flight surgeons recognize that ongoing vigilance is necessary to detect coronary artery disease (CAD) in aircrew. Regular physical examinations with only a resting electrocardiogram, albeit having a very low predictive value for detection of CAD in asymptomatic subjects, are now widely practised. Routine stress electrocardiography has been criticized for yielding too many so-called "false positive" results because ST/T changes that develop during and after exercise are prevalent.

A comparative study of atenolol, nifedipine and their combination in the treatment of hypertension.

The antihypertensive effects, as assessed by clinical and ambulatory blood pressure measurement, of nifedipine slow-release (SR), atenolol and the two in combination were evaluated in 28 known hypertensives in a placebo-controlled, double-blind, randomised cross-over trial. Clinical blood pressure was significantly lower on combination therapy (P less than 0.025) than on either agent alone, although all therapeutic agents reduced blood pressure significantly when compared with placebo (P less than 0.

Observer accuracy and confirmation of the important role of abnormal ST/T time course behavior in the evaluation of stress electrocardiograms.

Routine exercise electrocardiography has been criticized for yielding too many so-called "false-positive" results. Recent studies in our institution indicate that evaluation of the time course behavior of ST segment and T wave (ST/T) changes after cessation of exercise differentiates ischemic from non-ischemic ("false-positive") stress electrocardiograms (SEs). Our method of assessing time course behavior is clarified.

Evaluation of the post-exercise time-course behaviour of ST-segment and T-wave changes in the elimination of the false-positive stress ECG.

Routine stress ECG has been criticised for yielding too many so-called false-positive results because ST-segment and T-wave (ST/T) changes that develop during and after exercise are prevalent. Recent studies in our institutions indicate that the time-course behaviour patterns of ST/T configurational abnormalities after exercise reflecting myocardial ischaemia are different from those that do not. The epicardial coronary arteries of 111 patients, who had positive stress tests for ischaemia based on ST/T configurational changes alone but were considered non-ischaemic when the ST/T time-course behaviour was analysed, were assessed.

The aeromedical implications of atrial fibrillation.

A retrospective study was undertaken to determine the incidence of spontaneous atrial fibrillation (AF) in a group of asymptomatic pilots. The electrocardiograms of 13,037 aircrew members accumulated between 1964 and 1986 were reviewed and those coded for AF were extracted. In each case an attempt was made to investigate factors relating to the onset, course, and prognosis of the AF.

Long-term efficacy and safety of sustained-release diltiazem in the treatment of hypertension.

The long-term efficacy and safety of sustained-release diltiazem (Tilazem; Parke-Davis) were evaluated. A total of 27 young, physically active patients with hypertension were followed up for 17 months. On a dosage of 90 mg twice daily, adequate blood pressure reduction was obtained in 23 patients (85%).

Effects of therapy with diet and simvastatin on atherosclerosis in hypercholesterolemic patients.

We evaluated the effect of cholesterol reduction on atherosclerotic coronary artery lesions using diet and simvastatin, a potent HMG CoA reductase inhibitor. Fifteen subjects aged 28-69 years (mean 44), each of whom demonstrated significant (greater than 50%) narrowing of a coronary artery and a baseline cholesterol level greater than 278 mg/dl, were studied. Coronary arteriography was performed prior to and after 20 +/- 2.

Left anterior hemiblock in South African aircrew.

Serial ECGs and clinical records were examined to determine the prevalence, associated ECG abnormalities and outcome of left anterior hemiblock (LAH) in 13,037 airmen. The prevalence of LAH was 0.72% and it was not related to underlying cardiac disease.

Safety, tolerability and efficacy of acipimox in type II hyperlipidaemia.

Twenty-one patients with type II hyperlipidaemia were treated with the nicotinic acid analogue, acipimox (Olbetam; Farmitalia), for 6 months. Total cholesterol decreased by 10% and the high-density lipoprotein: low-density lipoprotein cholesterol ratio increased by 13%. Triglycerides were unaltered.

Bezafibrate and simvastatin (MK-733) in the treatment of primary hypercholesterolaemia.

Simvastatin, a new 3-hydroxy-3-methylglutaryl co-enzyme A reductase inhibitor, was compared to bezafibrate, a fibric acid derivative, in an open cross-over placebo-controlled study. Bezafibrate was administered as a 200 mg dose 3 times daily, while simvastatin dosage ranged from 10 mg to 40 mg once daily at night. Bezafibrate produced a non-significant 13.

Comparison between a low-osmolar ionic (ioxaglate) and a low-osmolar non-ionic (iopamidol) contrast agent in cardiac imaging.

The aim of this study was to compare the subjective, haemodynamic and electrocardiographic changes associated with a low-osmolar ionic (ioxaglate) and a low-osmolar non-ionic (iopamidol) injection during routine ventriculography and coronary angiography. The double-blind study was terminated when 120 patients had been randomised to either ioxaglate or iopamidol. More patients (9) experienced nausea with ioxaglate than with iopamidol (2).