Estrogen receptor alpha is essential for induction of oxytocin receptor by estrogen

The induction of oxytocin receptor (OTR) synthesis in the periphery and in the brain by estrogen is critical for reproductive success. Oxytocin receptors are involved in the control of parturition, milk ejection, and sexual and maternal behaviors. The discovery of a second estrogen receptor (ERbeta) in the brain and the failure of in vitro transcription studies using OTR promoter constructs to replicate the in vivo transcriptional regulation have raised questions regarding the molecular mechanisms involved in the regulation of the OTR gene by estrogen. Using mice genetically deficient in estrogen receptor alpha (ERalpha), we demonstrate that ERalpha is not necessary for basal OTR synthesis, but is absolutely necessary for the induction of OTR binding in the brain by estrogen.

Single-nucleotide polymorphisms in the public domain: how useful are they?

There is a concerted effort by a number of public and private groups to identify a large set of human single-nucleotide polymorphisms (SNPs). As of March 2001, 2.84 million SNPs have been deposited in the public database, dbSNP, at the National Center for Biotechnology Information (http://www.ncbi.nlm.nih.gov/SNP/). The 2.84 million SNPs can be grouped into 1.65 million non-redundant SNPs. As part of the International SNP Map Working Group, we recently published a high-density SNP map of the human genome consisting of 1.42 million SNPs (ref. 3). In addition, numerous SNPs are maintained in proprietary databases. Our survey of more than 1,200 SNPs indicates that more than 80% of TSC and Washington University candidate SNPs are polymorphic and that approximately 50% of the candidate SNPs from these two sources are common SNPs (with minor allele frequency of > or =20%) in any given population.

d-Sotalol: a new potent class III anti-arrhythmic agent

We have compared the effect of a new drug d-sotalol which has minimal beta-blocking action with the parent (beta-blocking) compound dl-sotalol on monophasic action potential (MAP) duration in open-chested dogs. In seven experiments d-sotalol was administered in intravenous bolus doses of 1.5, 3 and 6 mg/kg given at 10 min intervals. In a further seven experiments dl-sotalol was administered using the same dosage regimen. The animals were anaesthetized with chloralose and urethane. Atrioventricular block was created by injection of the bundle of His with 0.1 ml of 40% formalin in order to ensure capture by ventricular pacing. After prior beta-blockade with propranolol (0.25 mg/kg), simultaneous epicardial and endocardial MAP were recorded at paced heart rates of 100 and 150 beats/min after each bolus injection. d-Sotalol and dl-sotalol showed similar prolongation of MAP duration (measured at 90% repolarization) in both endocardial and epicardial recording at both paced heart rates. These results show that the dextro-isomer of sotalol possesses similar class III action to the parent compound and that this action is homogeneous with respect to left ventricular endocardium and epicardium at heart rates of 100 beats/min and 150 beats/min over a wide dose range. d-Sotalol may be a useful anti-arrhythmic agent in man.

Use of monophasic action potential recordings during routine coronary-artery bypass surgery as an index of localised myocardial ischaemia

In 8 patients undergoing routine coronary-artery bypass surgery, monophasic action potentials (MAPs) were measured by means of a hand-held pressure contact electrode to provide an index of local ischaemic changes. 4 patients received left internal mammary anastomoses (LIMA), and there were a total of 27 saphenous vein grafts (SVG). After completion of all grafts blood-flow to the myocardium was reduced for 90 s by means of different permutations of SVG and LIMA occlusion, either on or off bypass. In all patients MAPs indicated typical ischaemic changes. The high sensitivity of the method enables the study to be completed quickly and without hazard to the patient. The technique provides a new means to assess local ischaemia, the viability of specific areas of myocardium, and the efficiency of individual grafts during surgery.

Prevalence and clinical significance of aortic valve prolapse

The prevalence and clinical significance of aortic valve prolapse were determined prospectively in 2000 consecutive patients undergoing routine clinical cross sectional echocardiography. Two hundred and twelve patients were excluded because the aortic cusps were not adequately visualised. Aortic valve prolapse was defined as downward displacement of cuspal material below a line joining the points of attachment of the aortic valve leaflets. Twenty four cases of aortic valve prolapse (1.2%) were identified. The patients were aged 12-64 years and nine were women. All had underlying valvar heart disease and the commonest lesion (in 11 cases) was prolapse of the larger cusp in bicuspid valves. Aortic valve prolapse was seen in four patients with mitral valve prolapse (two with severe regurgitation), one of whom had marfanoid aortic root dilatation. The remaining examples of aortic prolapse were seen in patients with various disorders including one with pulmonary atresia, two with aortic root disease (one with dissection and one with idiopathic dilatation), and one case of severe mitral regurgitation. Valves destroyed by infective endocarditis were seen in two cases. Aortic valve prolapse may be detected in various cardiac disorders and does not imply the presence of aortic regurgitation, but when bicuspid aortic valves are present it may well be important in producing such regurgitation. Although aortic valve prolapse may be associated with severe forms of mitral valve prolapse, these patients rarely have aortic regurgitation.

Exercise testing after beta-blockade: improved specificity and predictive value in detecting coronary heart disease

The value of exercise testing in detecting myocardial ischaemia resulting from coronary atheroma remains controversial. In order to increase the reliability of exercise testing, all its components (asymptomatic, haemodynamic, and electrocardiographic) have been scrutinised. In this study, concerned only with the electrocardiographic response to exercise, the incorporation of beta-blockade into the standard exercise procedure has improved specificity and predictive value without affecting sensitivity. Fifty patients with anginal pain and 50 asymptomatic subjects with an abnormal electrocardiogram were investigated by exercise testing before and after beta-blockade (oxprenolol). All subjects had coronary arteriograms and left ventriculograms, and the results of exercise testing were related to the presence or absence of obstructive coronary artery disease. Possible causes of false positive exercise tests were eliminated by echocardiography. Though beta-blockade was unreliable in distinguishing ischaemic from non-ischaemic resting electrocardiograms, it eliminated all the false positive electrocardiographic responses to exercise in both groups and did not abolish any of the true positive electrocardiographic responses. Thus, specificity and predictive value were improved without reduction in sensitivity. This technique may not necessarily be applicable to other groups of patients or to a random population, but the results of this study suggest it will be a useful additional routine procedure in the investigation of coronary heart disease.

Influence of angiotensin converting enzyme inhibition on exercise performance and clinical symptoms in chronic heart failure: a multicentre, double-blind, placebo-controlled trial

One hundred and seven patients with chronic heart failure (NYHA class II to IV) stabilized on digitalis and/or diuretics, recruited from 11 centres were randomized into a double-blind, placebo-controlled study to assess the effect of 12 weeks of cilazapril therapy on exercise tolerance and clinical status. Thirty-five patients were randomized to placebo and 72 to cilazapril at a starting dose of 1 mg daily; titration to cilazapril 2.5 mg at week 4 and 5 mg at week 8 (or matching placebo) was carried out in patients who did not improve clinically. Demographic characteristics, including exercise test duration increased from 402 s (+/- 17 SEM) at baseline to 462 s (+/- 19 SEM) at week 12 for the cilazapril group (+15%) and from 405 s (+/- 23 SEM) at baseline to 408 s (+/- 30 SEM) at week 12 in patients on placebo (+1%) (P < 0.001). In the placebo group, patients able to exercise for more than 6 min at baseline showed an increase in exercise duration at week 12 while those able to exercise for up to 6 min at baseline showed a decrease (P = ns). In contrast, cilazapril-treated patients showed an increase in exercise tolerance regardless of baseline exercise test duration; patients with the most impaired exercise tolerance at baseline showed a greater improvement than patients with mildly impaired baseline exercise tolerance (P < 0.05 vs placebo). NYHA class improved by at least one grade in 51% of the cilazapril group vs 32% in the placebo group (P = ns). At the end of the trial, 15% of the patients were non-responders on cilazapril vs 41% on placebo (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Linkage disequilibrium maps constructed with common SNPs are useful for first-pass disease association screens

To develop an efficient strategy for mapping genetic factors associated with common diseases, we constructed linkage disequilibrium (LD) maps of human chromosomes 5, 7, 17, and X. These maps consist of common single nucleotide polymorphisms at an average intermarker distance of 100 kb. The genotype data from these markers in a panel of American samples of European descent were analyzed to produce blocks of markers in strong pair-wise LD. Power calculations were used to guide block definitions and predicted that high-level LD maps would be useful in initial genome scans for susceptibility alleles in case-control association studies of complex diseases. As anticipated, LD blocks on the X chromosome were larger and covered more of the chromosome than those found on the autosomes.

Feeding Flipper: a case study of a humandolphin interaction

We document a human-dolphin interaction involving the illegal feeding of wild Bottlenose Dolphins (Tursiops sp.) in Cockburn Sound, Western Australia from 1993-2003. In 1993 only one dolphin was considered conditioned to human interaction through food reinforcement. By 2001, 16% (n = 12) of the resident community of 74 adult dolphins were conditioned, and at least 14 dolphins were conditioned by 2003. Of the 13 conditioned dolphins of known sex, 11 (85%) were males. We observed conditioned dolphins initiating interactions by approaching recreational fishing boats and by residing for several hours at boat ramps and shore-based fishing sites. We only observed recreational fishers feeding dolphins, although anecdotal reports indicated additional feeding sources. We used belt transects to determine the densities of recreational boats and encounter rates for conditioned dolphins across habitats within Cockburn Sound. Encounter rates and boat densities were positively correlated, suggesting an association between recreational boat density and the ranging patterns of conditioned dolphins. This study demonstrates how illegal feeding interactions can intensify over time to affect a potentially biologically significant proportion of a local dolphin population. This emphasizes the need for early and pro-active intervention and demonstrates the value of longitudinal, individual-specific wildlife studies.

Effects of opioids on phagocytic function, oxidative burst capacity, cytokine production and apoptosis in canine leukocytes

Opioids alter immune and apoptotic pathways in several species. They are commonly used in companion animals affected with infectious and/or inflammatory disease, but the immunomodulatory and apoptotic effects of these drugs in dogs are relatively unknown. The aim of the present study was to evaluate the effects of morphine, buprenorphine and fentanyl on canine phagocyte function, oxidative burst capacity, leukocyte cytokine production, and lymphocyte apoptosis. Blood from six healthy adult dogs was incubated in the presence or absence of morphine (200 ng/mL), buprenorphine (10 ng/mL) or fentanyl (10 ng/mL) for 3 h (phagocytic function; cytokine production) or 8 h (apoptosis). Neutrophil phagocytosis of opsonized Escherichia coli, respiratory burst capacity after stimulation with opsonized E. coli or phorbol 12-myristate 13-acetate (PMA), and Annexin V-FITC staining of apoptotic lymphocytes were evaluated using flow cytometry. Leukocyte production of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-10 was assessed after incubation with lipopolysaccharide (LPS), lipoteichoic acid (LTA) or peptidoglycan. Morphine promoted a more intense respiratory burst. Morphine, buprenorphine and fentanyl all promoted LPS- or LTA-induced TNF-α and IL-10 production. However, the opioids tested did not alter TNF-α:IL-10 ratios. Morphine, buprenorphine and fentanyl all inhibited neutrophil apoptosis, an effect that was not concentration dependent in nature. These data indicate that opioids alter immune and apoptotic pathways in dogs. The possible effects of opioids on immune and cellular responses should be considered when designing studies and interpreting outcomes of studies involving administration of opioids in dogs.

Estimated glomerular filtration rate progression in UK primary care patients with type 2 diabetes and diabetic kidney disease: a retrospective cohort study

AIMS

To examine the rates of diabetic kidney disease (DKD) progression and associated factors, we undertook a study of estimated glomerular filtration rate (eGFR) in a historical cohort of UK primary care patients with type 2 diabetes mellitus (T2DM) and associated DKD from the Clinical Practice Research Datalink.

METHODS

Our eligible population were patients with definitive T2DM from a recorded diagnostic code with either a diagnosis of chronic kidney disease (CKD) or renal function test values and renal abnormalities consistent with a CKD diagnosis, identified between 1 October 2006 and 31 December 2011. Only patients with albuminuria results reported in mg/l were used for the longitudinal statistical analyses of the eGFR rate of change using multilevel models.

RESULTS

We identified 111,030 patients with T2DM. Among them 58.6% (95% confidence interval (CI): 58.3-58.9) had CKD and 37.2% (95% CI: 36.9-37.5%) had presumed DKD at baseline. Only 19.4% of patients had urinary albumin test results expressed as mg/l in the year prior to index date. Almost two-thirds (63.8%) of patients with T2DM and presumed DKD received prescriptions for angiotensin-converting enzyme (ACE) inhibitors or angiotensin type 1 receptor blockers (ARB) or both. Time-dependent variables that predict subsequent eGFR decline include increased albuminuria, time from index date and older age.

CONCLUSION

Only a minority of diabetic patients with DKD had quantitative albuminuria assessments. The relatively low proportion of DKD patients with ACEi or ARB prescriptions suggests a gap between healthcare practice and available scientific evidence during the study period. Increased albuminuria and older age were the most consistent predictors of subsequent eGFR decline.

Class III action of beta-blocking agents

We have studied the effect of the intravenous administration of the following drugs on ventricular refractoriness in 35 experiments in open chested beagle dogs: atenolol 0.2 mg X kg-1; nadolol 0.05 mg X kg-1; oxprenolol 0.2 mg X kg-1; pindolol 0.04 mg X kg-1; propranolol 0.2 mg X kg-1; sotalol 0.6 mg X kg-1 and timolol 0.1 mg X kg-1. The animals were anaesthetised with chloralose and urethane. Measurements were made of left ventricular epicardial monophasic action potentials (MAP) (n = 35) and the left ventricular paced evoked response (PER) (n = 25) at a fixed paced cycle length of between 220 and 310 ms. The animals were initially beta-blocked with iv pindolol or propranolol and the drug under study then administered iv 10 min later. The results were as follows: (control and post drug administration) MAP: nadolol 151 +/- 12 SD to 172 +/- 13 SD (p less than 0.001); oxprenolol 153 +/- 21 to 178 +/- 20 (p less than 0.001); sotalol 153 +/- 19 to 176 +/- 20 (p less than 0.001); atenolol 152 +/- 25 to 153 +/- 23 (NS); pindolol 149 +/- 11 to 152 +/- 10 (NS); propranolol 152 +/- 26 to 155 +/- 26 (NS); timolol 144 +/- 23 to 144 +/- 21 (NS). PER: nadolol 172 +/- 14 to 190 +/- 20 (p less than 0.001); oxprenolol 164 +/- 16 to 188 +/- 15 (p less than 0.001); propranolol 166 +/- 22 to 173 +/- 18 (NS).(ABSTRACT TRUNCATED AT 250 WORDS)

99mTc-imidodiphosphonate: a superior radio-pharmaceutical for in vivo positive myocardial infarct imaging. II: Clinical data

99mTc-Imidodiphosphonate was investigated as a new myocardial infarct imaging agent. In the acute phase, 50 patients admitted to the coronary care unit were serially scanned over a period of 7 days. A mobile gamma camera linked on line to a remote data processor was used. Because of higher uptake in infarcted myocardium and faster blood clearance, superior images than those recorded with 99mTc-pyrophosphate were obtained. Its ease of preparation, low cost, and favourable dosimetry (because of its label with conventional 99mTc) transforms this agent into the present radiopharmaceutical of choice for acute infarct imaging in particular if sizing and follow-up is intended versus time and type of treatment. In this series, no false positive cases were seen. The sensitivity of the method in the detection of full thickness myocardial infarction was 95%. It dropped to 70% in the detection of subendocardial infarction. However, some of these apparent false negative cases may reflect severe ischaemia without infarction. It is postulated that this discrimination may not always be realistic.

Effect of isoprenaline and nitroglycerine on pressure time indices and coronary graft blood flow in man

In five patients studied 1 to 3 d after coronary artery surgery isoprenaline and nitroglycerine have been used to alter the systolic (TTI) and diastolic (DPTI) pressure time indices. A close correlation with the predicted relationship between diastolic coronary graft flow and the DPTI/TTI ratio has been demonstrated during isoprenaline-induced tachycardia. Nitroglycerine reduced diastolic coronary graft resistance and increased the DPTI/TTI ratio, effects which are desirable for the relief of angina.

A method for parallel, automated, thermal cycling of submicroliter samples

A large fraction of the cost of DNA sequencing and other DNA-analysis processes results from the reagent costs incurred during cycle sequencing or PCR. In particular, the high cost of the enzymes and dyes used in these processes often results in thermal cycling costs exceeding $0.50 per sample. In the case of high-throughput DNA sequencing, this is a significant and unnecessary expense. Improved detection efficiency of new sequencing instrumentation allows the reaction volumes for cycle sequencing to be scaled down to one-tenth of presently used volumes, resulting in at least a 10-fold decrease in the cost of this process. However, commercially available thermal cyclers and automated reaction setup devices have inherent design limitations which make handling volumes of <1 microL extremely difficult. In this paper, we describe a method for thermal cycling aimed at reliable, automated cycling of submicroliter reaction volumes.

Value of positive myocardial infarction imaging in coronary care units

Positive myocardial imaging was undertaken on 120 unselected patients admitted to a coronary care unit with clinical suspicion of acute myocardial infarction. Multipurpose mobile gamma-cameras were used for serial imaging after administration of 99mtechnetium-labelled imidodiphosphonate, a low-cost radiopharmaceutical that is 97% specific for myocardial necrosis, with myocardial uptake and blood clearance most suitable for myocardial imaging. The sensitivty of detection was 94% for patients whose infarction was unequivocal on the ECG; when the presence of raised enzyme concentrations was also used as a criterion for myocardial necrosis, the overall sensitivity for all 120 patients remained 94%. In 73 patients (61%), whose ECGs were unhelpful or difficult to interpret, scintigraphy allowed infarction to be diagnosed in 11 (15%) and to be excluded in five (7%). In 32 (44%) of this group whose ECGs were totally uninterpretable due to previous myocardial damage or disorders of electrical activation, scintigraphy provided confirmation of a diagnosis that otherwise rested only on whether enzyme concentrations were raised. Myocardial imaging is thus a useful technique that permits more definite diagnosis in patients for whom ECG and enzyme data are uncertain.