Long-term antihypertensive therapy with isradipine. Improvement of coronary flow reserve in patients with arterial hypertension and microvascular angina

Antihypertensive Long-term Therapy with Isradipine/Improvement of coronary flow reserve in patients with arterial and microvascular angina In patients with arterial hypertension coronary flow reserve is often impaired due to left ventricular (LV) hypertrophy and alterations of the coronary microcirculation. Experimental and clinical studies have shown that calcium channel blockers can induce regression of myocardial hypertrophy. Objective of the present study was to see whether chronic antihypertensive treatment with calcium channel blockers can improve the diminished coronary reserve in patients with arterial hypertension and microvascular angina pectoris. Fifteen hypertensive patients with microvascular angina (61 +/- 7 years, normal coronary angiogram, mild LV-hypertrophy) were treated with isradipine (CAS 75695-93-1) (5.3 +/- 0.9 mg/d) for 12 +/- 2 months. Before and after therapy (after a washout period of 1 week) coronary flow was quantitatively measured by the gas chromatographic Argon method. Coronary reserve was calculated as the quotient of coronary resistance under baseline conditions and after dipyridamole (0.5 mg/kg i.v.). Under isradipine therapy systolic blood pressure was lowered from 165 +/- 20 to 140 +/- 13 mmHg (p < 0.01) and diastolic blood pressure from 98 +/- 8 to 88 +/- 6 mmHg (p < 0.01). The LV muscle mass index decreased by 10% from 154 +/- 33 to 139 +/- 28 g/m2 (p < 0.05). Baseline coronary blood flow (81 +/- 13 versus 83 +/- 16 ml/min x 100 g, n.s.) was identical before and after therapy. There were also no differences in coronary perfusion pressure, heart rate, myocardial oxygen consumption and arterio-coronary venous oxygen difference before and after therapy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Thermofluid-neutronic stability of the rotating, fluidized bed, space-power reactor

A rotating fluidized bed nuclear reactor has the potential of being a vary attractive option for ultra-high power space systems, especially for propulsion. Research has already examined fuel bed expansion due to variations in state variables, propellant flow rate, and rotational speed, and has also considered problems related to thermal stress. This paper describes the results of a coupled thermofluid-neutronic analysis where perturbations in fuel bed height caused by maneuvering changes in operating conditions alter power levels due to varying absorption of neutrons which would otherwise leak from the system, mainly through the nozzle. This first analysis was not a detailed stability analysis. Rather, it utilized simplified neutronic methods, and was intended to provide an order-of-magnitude assessment of the stability of the reactor with the intention to determine whether or not stability might be a “concept killer”.Stability was compared with a fixed-fuel-bed reactor of identical geometry for three different cases comprising a set of small, medium and large sizes/powers from 250 MW to 5 GW. It was found that power fluctuations in the fluidized bed reactor were larger by 100 db or more than expected in a packed bed reactor of the same geometry, but never resulted in power excursions. Margins to unit gain in some cases, however, were sufficiently small that the approximations in this quasi-2-dimensional model may not be sufficiently accurate to preclude significant excursions.     

The installation and support of internationally distributed equipment for people with dementia

This paper describes the evaluation and support of assistive technology designed to increase the independence of people with dementia. Devices were evaluated by people with dementia in their own homes. Working with and supporting people with dementia requires relational skills not normally needed by installers and technical supporters.     

Imitation, copying, and the use of models: report writing in an introductory physics course

The article focuses on the use and misuse of models-both appropriate and inappropriate-in the report-writing practices of first year physics students, especially those from non-English speaking backgrounds. It analyzes the students' propensity to use any available text on a given topic as a source of model sentences. Examples of "copying" are provided and analyzed. It is argued that many forms of copying are legitimate learning strategies of novice writers, for the production of certain kinds of texts, but that this can become a problem when inappropriate models are used or when appropriate models are used inappropriately. Copying is discussed in relation to imitative learning and modeling as well as plagiarism, and some suggestions to improve teaching practice are made.     

MIMO Generalized Predictive Control for a Hydroelectric Power Station

In this paper, the approach of generalized predictive control (GPC) is applied to a multivariable model of the Dinorwig pumped-storage hydroelectric power station. The response of the system with constrained predictive control is compared with the classic PI controller as currently implemented. The results show that GPC offers significantly better performance across the plant's operating range. It is shown that fixed-parameter, constrained GPC produces a faster primary response when the station is operating with a single unit while preserving stability as the operating conditions change when multiple units are online     

Visual sharpness contingency in recognition memory for orientation: Mnemonic illusion suppressed by sensory signature.

A striking finding about human memory is that people's level of accuracy in remembering the orientation of heads on coins is often not simply at the chance level but significantly below it. However, S. W. Kelly, A. M. Burton, T. Kato, and S. Akamatsu (2001) reported that this is not so when two-alternative forced-choice visual recognition is employed. The Kelly et al. result could not be replicated here with a copy of their stimuli. However, the result was successfully replicated with newly created stimuli. A series of experiments provided converging evidence that the mnemonic illusion is suppressed when recognition alternatives possess sharp visual detail. The role of a sensory signature in suppressing the mnemonic illusion and in modulating visual recognition performance in general is delineated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Triploidy: antenatal sonographic features with post-mortem correlation

The CD34 antigen is expressed by human hematopoietic progenitor and stem cells. These cells are capable of reconstituting marrow function after marrow-ablative chemo-radiotherapy. Several different technologies have been developed for the separation of CD34+ cells from bone marrow or peripheral blood stem cell (PBSC) components. We used an immunomagnetic separation technique to enrich CD34+ cells from PBSC components in anticipation of autologous transplantation for patients with B lymphoid malignancies. Twenty-nine patients enrolled on this study and received mobilization chemotherapy followed by G-CSF. Of these, 21 achieved a peripheral blood CD34+ cell level of at least 2.0 x 10(4)/l required by protocol for separation of the stem cell components. A median of three components per patient was collected for processing. The average CD34+ cell concentration in the components after apheresis was 1.0 +/- 1.2%. After the CD34+ cell selection, the enriched components contained 0.6 +/- 0.6% of the starting nucleated cells. The recovery of CD34+ cells, however, averaged 58.4 +/- 19.2% of the starting cell number, with a purity of 90.8 +/- 6.5%. Overall depletion of CD34- cells was 99.96 +/- 0.06%. Nineteen patients were treated with marrow-ablative conditioning regimens and received an average of 6.2 +/- 2.0 x 10(6) CD34+ cells/kg body weight. These patients recovered to an ANC >0.5 x 10(9)/l at a median of 11 days (range 8-14), and platelet transfusion independence at a median of 9 days (range 5-13). Four patients died of transplant-related complications or relapse before 100 days after transplantation. No patient required infusion of unseparated cells because of failure of sustained bone marrow function. These data demonstrate that peripheral blood-derived CD34+ cells enriched by use of an immunomagnetic separation technique are capable of rapid engraftment after autologous transplantation.     

Follow-up of TIPS: evaluation of signs of dysfunction with Doppler ultrasonography

The anemia of malignancy is common and is related to several etiologic factors, a major one being relative erythropoietin (Epo) deficiency. Blood transfusions, the traditional therapy, provides a quick solution but is associated with complications. This was the rationale for recombinant human Epo (rHuEpo) in the treatment of anemia of cancer. Over the past few years, about 20 publications have reported the results of rHuEpo in the treatment of cancer-associated anemia in more than 850 patients with a variety of malignancies. In general, more than half of the patients responded with a significant increase in their hemoglobin level, a decrease in blood transfusion requirements, and an improved performance status and quality of life. About 4 weeks are required till the onset of effect. The hormone is well tolerated with minimal adverse effects and subcutaneous injections appear to be the preferred method of administration. Additional studies will hopefully answer several questions including optimal dosage and duration of treatment, Epo resistance, and the possibility of predicting the response.     

Absence of PTEN/MMAC1 germ-line mutations in sporadic Bannayan-Riley-Ruvalcaba syndrome

Bannayan-Riley-Ruvalcaba syndrome (BRRS) is a rare hamartomatous polyposis condition with features of macrocephaly, intestinal juvenile polyposis, developmental delay, lipomas, and pigmentation spots of the male genitalia. An autosomal dominant pattern of inheritance exists in some families, but others appear as sporadic cases. Germ-line mutations in PTEN, a tyrosine phosphatase and putative tumor suppressor gene, have been demonstrated in two families with BRRS, and chromatin loss at the PTEN gene locus on chromosome 10q23 has been demonstrated in two BRRS patients. Germ-line mutations in PTEN have also been described in Cowden disease and in a small number of patients with juvenile polyposis syndrome. In an attempt to assess the nature of PTEN mutations in BRRS, we analyzed three sporadic BRRS patients for chromosome 10q23 deletion or PTEN germ-line mutations. All 3 patients demonstrated no loss of parental alleles at 15 chromosome 10q23 markers that encompassed the region of PTEN. In addition, analysis of mRNA and genomic DNA revealed no nonsense, missense, or insertion/deletion mutations of PTEN. Thus, other mechanisms besides mutation of PTEN must have occurred to cause BRRS in these patients. We speculate that BRRS and juvenile polyposis syndrome may have a heterogeneous etiology to cause their syndromes.