Characterization of Giardia isolates using a non-radiolabeled DNA probe, and correlation with the results of isoenzyme analysis

Forty-seven isolates, identified morphologically as Giardia duodenalis, were compared by restriction endonuclease analysis of DNA with hybridization to a non-radiolabeled probe. Seven schizodemes were distinguished, compared to 15 zymodemes identified by isoenzyme electrophoresis. Despite the greater sensitivity of isoenzyme electrophoresis, DNA analysis did detect previously unsuspected variations between isolates in 1 zymodeme. Eighteen different genetic groups were detected among the 49 isolates by isoenzyme and DNA analyses. Genetic differences between groups, calculated from DNA restriction fragment variation, were significantly correlated with differences calculated from allozyme variation. This correlation between the 2 techniques suggests that G. duodenalis consists of a complex of genetically diverse clones. Such a genetic structure has important implications for the taxonomy of Giardia and the epidemiology of giardiasis.     

Bclx regulates the survival of double-positive thymocytes.

The bclx gene has been shown to regulate programmed cell death in vitro. We now show that Bclx expression increases dramatically when T cells differentiate from CD4- CD8- (double negative) thymocytes to CD4+ CD8+ [double positive (DP)] thymocytes. In contrast single-positive (SP) thymocytes express negligible amounts of Bclx protein. This expression pattern contrasts with that of Bcl2, which is present in double-negative thymocytes, down-regulated in DP thymocytes, and reinduced upon maturation to SP thymocytes. Elimination of Bclx by gene targeting dramatically shortens the survival of DP thymocytes but not the survival of SP thymocytes or peripheral SP T cells. These data suggest that the induction of Bclx during thymic maturation plays a critical role in regulating the length of time DP thymocytes survive in the absence of selection.     

Acute haemodynamic and metabolic effects of dopexamine, a new dopaminergic receptor agonist, in patients with chronic heart failure.

Dopexamine, a new compound with postjunctional dopamine receptor activating and beta adrenoceptor agonist properties, was given to 10 patients with chronic heart failure at diagnostic cardiac catheterisation to investigate its acute haemodynamic and metabolic effects. The drug was administered by intravenous infusion in three incremental doses and produced significant dose related increases in cardiac index, stroke volume index, and heart rate and falls in systemic vascular resistance and left ventricular end diastolic pressure; aortic and pulmonary artery pressures were unchanged. Isovolumic phase (max dP/dt and KVmax) and ejection phase (peak aortic blood velocity, maximum acceleration of blood, and maximum rate of change of power with time during ejection) indices of myocardial contractility were all increased by dopexamine but these changes were hard to interpret in the presence of an increase in heart rate. Myocardial efficiency and ejection fraction were both increased and left ventricular end diastolic and end systolic volumes fell. These largely beneficial changes were achieved without a statistically significant increase in myocardial oxygen consumption or disturbance of myocardial metabolic function. Dopexamine was well tolerated but tremor was reported by two patients at the intermediate dose and mild chest pain by two patients at the high dose.     

N-Methyl-d-Aspartate-Stimulated Increases in Intracellular Calcium Exhibit Brain Regional Differences in Sensitivity to Inhibition by Ethanol

This study compared N -methyl- d -aspartate (NMDA)-stimulated increases in intracellular calcium in fura-2–loaded neurons dissociated from newborn rat brainstem (EC₅₀ in μM; 6.4), cerebellum (9.5), forebrain (6.3), and hippocampus (10.6). Ethanol inhibition of the response to 25 μM NMDA differed among the regions. The NMDA response in hippocampus was inhibited by 20 mM ethanol; cortex and cerebellum responses were inhibited by 80 mM ethanol, and no inhibition was seen in the brainstem. Addition of glycine (15 μM) failed to attenuate ethanol inhibition of the NMDA response. These results demonstrate that ethanol inhibition of NMDA-stimulated responses varies according to brain region. In contrast to previous findings from this laboratory using dissociated neurons from whole brain, the addition of glycine did not reverse the inhibitory effects of ethanol on NMDA-stimulated responses.     

Lipids,lipoproteins, and exercise

PURPOSE: Dose-response relationships between exercise training volume and blood lipid changes suggest that exercise can favorably alter blood lipids at low training volumes, although the effects may not be observable until certain exercise thresholds are met. METHODS AND RESULTS: Plasma triglyceride reductions are often observed after exercise training regimens requiring energy expenditures similar to those characterized to increase high-density lipoprotein cholesterol (HDL-C). Thresholds established from cross-sectional and longitudinal exercise training studies indicate that 15 to 20 miles/week of brisk walking or jogging, which elicit between 1,200 to 2,200 kcals of energy expenditure per week, is associated with triglyceride reductions of 5 to 38 mg/dL and HDL-C increases of 2 to 8 mg/dL. Exercise training seldom alters total cholesterol and low-density lipoprotein cholesterol (LDL-C) unless dietary fat intake is reduced and body weight loss is associated with the exercise training program, or both. Thus, for most individuals, the positive effects of regular exercise are exerted on blood lipids at low training volumes and accrue so that noticeable differences frequently occur with energy expenditures of 1,200 to 2,200 kcals/week. CONCLUSIONS: It appears that weekly exercise caloric expenditures that meet or exceed the higher end of this range are more likely to produce the desired lipid changes. Regarding hyperlipidemic disorders, the primary means for intervention is pharmacologic, whereas diet modification, weight loss, and exercise, although important, are viewed as adjunctive therapies. Because much is known about the exercise training-induced plasma lipid and lipoprotein modifications as well as the mechanisms responsible for these changes, rehabilitation professionals can better develop a comprehensive medical management plan that optimizes pharmacologic, reduced dietary fat intake, weight loss, and exercise interventions.     

Detection of lung perfusion abnormalities using computed tomography in a porcine model of pulmonary embolism

The purpose of this study was to identify perfusion defects of the lung using computed tomography (CT). A balloon catheter was placed in a lobar pulmonary artery of six anesthetized, ventilated, juvenile pigs to simulate occlusive segmental embolus. Contrast medium was injected via a central venous catheter at rates of 1.5, 3, 4.5, and 9 ml/s in each pig. A 40-second single-level cine CT was acquired distal to the inflated balloon during suspended inspiration. Three computer-manipulated images (time to maximal enhancement, change in maximal attenuation, maximal contrast minus precontrast subtraction) were generated using custom software and compared with the unmodified maximal enhancement and precontrast images. Two independent observers identified perfusion defects and scored the level of confidence (5-point scale) on all five images. Regions of interest were drawn in perfused and nonperfused lung and time-attenuation curves were generated. Perfusion defects were accurately (99.8 +/- 0.3%) and confidently (4.5 +/- 0.6) detected and there was excellent interobserver agreement (Kappa 0.99 +/- 0.02) on all computer-manipulated images. There was a significant increase in confidence (p < 0.05) between contrast medium injection rates of 1.5 and 9 ml/s. A linear relationship exists (r = 0.88) between injection rate and change in maximal attenuation. In conclusion, perfusion defects of the lung are seen using computer-manipulated CT images.     

Mothers’ experiences of the NICU and a NICU support group programme

Objective: to understand both the maternal experience of the NICU and mothers’ views of a NICU Parent Support Group. Background: mothers of babies who are born prematurely have their first experiences of parenting while their infant is in the neonatal intensive care unit (NICU). This presents multiple challenges and a range of stresses related to their role as a mother and concerns about their baby’s survival and growth. Thus, various supportive interventions have been trialled with this NICU parent population. However, the focus of this support and how it should be delivered lacks research as an evidence base for practice. Mothers’ experiences of the NICU and a professionally facilitated NICU support group at a city hospital were explored in this qualitative research study. Method: nine mothers were interviewed in 2010 while their babies were NICU inpatients. Interviews were recorded, transcribed and analysed thematically. Results: the NICU admission resulted in participant mothers facing challenges in getting to know their baby, forming their parenting role while in the NICU, and a reliance upon, but resentment toward, nursing staff. Positive feelings about their baby’s strengths were also apparent. The parent support group was an important part of managing the experience of the NICU and was reported to meet the emotional support needs of these NICU parents. Conclusion: the implications and recommendations for NICU-based emotional support are discussed. In particular, modifications to support group structures to ensure professional staff involvement and a balance between education and emotional care are reviewed.     

An evaluation of a nurse-led Comprehensive Child Development Service in Hong Kong

Objective: The objectives of this study were to evaluate a nurse-led Comprehensive Child Development Service aimed at reducing depression and increasing satisfaction with care among a group of high-risk pregnant women. Background: Many studies have indicated that mental health problems, substance abuse, teenage pregnancy and poor social support for single mothers are associated with poor outcomes in fetal and child development. Pre-term delivery and low birth weight can be found in mothers engaging in substance abuse. The nurse-led Comprehensive Child Development Service includes an early identification and referral system for families in need that is geared towards providing better care and ensuring better health outcomes and positive life courses for children and families. Methods: A single group pre-test post-test design was used and participants – 74 pregnant women who presented with symptoms of low mood, had separated from their partners or had a history of illicit drug use – were recruited from an outpatient clinic in Hong Kong. Depression and satisfaction were measured by the Edinburgh Postnatal Depression Scale and a self-developed questionnaire respectively. Results: Participants reported a significant reduction in depression and a high level of satisfaction with the service. Conclusion: The study demonstrates that the Comprehensive Child Development Service has a positive impact on pregnant women.