Relationship between intrarenal distribution of blood flow and renin secretion during ureteral occlusion

The present study was undertaken to evaluate the relationship between renin secretion from the denervated kidney and intrarenal distribution of blood flow during reductions in renal perfusion pressure by partial constriction of the aorta with and without ureteral occlusion in the anesthetized dog. In addition, renin contents in different zones of the kidney were measured. A reduction in renal arterial pressure from normal pressure (125-135 mmHg) to 77 mm Hg resulted in significant increase in renin secretion and redistribution of cortical blood flow. A further reduction of renal arterial pressure to 51 mmHg produced a marked increase in renin secretion rate (RSR) without further changes in the intrarenal distribution pattern of blood flow. The pressure reductions during ureteral occlusion increased RSR without any change in the distribution pattern of blood flow, and a decrease in the amounts of extractable renin was found in the outer cortex of the experimental kidney. These findings suggest that renin release occurs mainly in the outer cortex, and this process may be stimulated when the mechanism of autoregulation fails as the perfusion presure approaches to the lower range of autoregulation in the outer cortex.     

Can gonadal steroids influence cell position in the developing brain?

The preoptic area/anterior hypothalamus (POA/AH) is a site where hormones dramatically influence development. The POA/AH is comprised of multiple subgroups, but little is known about the derivation of these subgroups during development. Results from several laboratories suggest that some cells in the POA/AH originate from progenitor cells in other regions of the developing nervous system. We are exploring pathways for migration in the developing POA/AH in two ways. First, we are examining the distribution of radial glial processes as potential migratory guides using immunocytochemistry. We have identified a transient pattern of radial glial processes from the lateral ventricles to the pial surface at the base of the POA/AH. Additionally, the expression of a molecule in radial glial processes originating in the third ventricle was decreased by prenatal treatment with testosterone. Second, we are utilizing time-lapse video microscopy in vitro to assess the extent and direction of movements of fluorescent dye-labeled cells at different ages in brain slice preparations from the POA/AH of developing rats. Data from these studies indicate that cell migration in the POA/AH includes movements along dorsal-ventral routes and from lateral to medial positions, in addition to the predicted medial to lateral pathway away from the third ventricle. Several researchers have examined effects of gonadal steroids on neurite outgrowth, cell differentiation, cell death, and synaptogenesis. The determination of cell position, however, may be a key event influenced by gonadal steroids earlier in development. The characterization of migratory pathways that contribute to permanent changes in brain structure and ultimately function is essential for unraveling the process of sexual differentiation.     

Aggressive behaviors in adult SF-1 knockout mice that are not exposed to gonadal steroids during development.

Sex hormones are a major factor responsible for the development of sex differences. Steroidogenic factor 1 (SF-1) is a key regulator of gonadal and adrenal development, and SF-1 knockout mice (SF-1 KO) are born without gonads and adrenal glands. Consequently, these mice are not exposed to gonadal sex steroids. SF-1 KO pups die shortly after birth due to adrenal deficiency. In the present study, SF-1 KO mice were rescued by neonatal corticosteroid injections followed by adrenal transplantations on day 7-8 postnatally. Control mice received corticosteroid injections and were gonadectomized prior to puberty. Mice were observed interacting with ovariectomized hormone primed females and gonad-intact males. In the absence of sex steroid replacement, adult SF-1 KO mice were significantly more aggressive than control mice in tests with stimulus females. After testosterone treatment, control males displayed significantly more aggression towards male intruders than control female mice, or male and female SF-1 KO mice, suggesting a developmental role of gonadal hormones in the expression of aggressive behavior and affirming SF-1 KO mice as a behavioral model to investigate affects of fetal gonad deficiency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationship between blood pressure and renal function

RENAL DAMAGE CAUSED BY HYPERTENSION: Renal vasoconstriction seems to be a key factor in the origin of arterial hypertension and accounts for the decrease in renal blood flow commonly observed in patients with hypertension. An inverse correlation has been found between renal blood flow and clinic blood pressure levels in established hypertension. Other features of renal damage attributable to high blood pressure have also been correlated with clinic blood pressure levels. Microalbuminuria is a good example of an alteration in renal function that depends in part on blood pressure levels. EFFECTS OF ANTIHYPERTENSIVE AGENTS: Antihypertensive agents can prevent or ameliorate renal vascular damage secondary to arterial hypertension, including renal failure. Ambulatory blood pressure monitoring is an excellent method of studying blood pressure levels in relation to end-organ damage and the blood pressure response to antihypertensive agents. Preliminary studies using this technique indicate that changes in renal function are closely correlated with the average daily blood pressure in arterial hypertension. CONCLUSIONS: Further studies are needed on the mechanisms of renal deterioration and on how to preserve renal function in arterial hypertension.     

血液黏稠度增高与不孕症关系的探讨

目的探讨血液流变学指标异常对不孕症的影响.方法对治疗组48例不孕症患者治疗前、治疗后分别进行血液流变学指标检测,并与对照组20例健康育龄女性的血液流变学指标进行比较.结果治疗组治疗前与对照组比较全血黏度高切、中切、低切均增高(P＜0.01),红细胞压积增高(P＜0.05),血浆黏度、红细胞沉降率与对照组比较无明显差异(P＞0.05).经活血理气中医治疗后治疗组治疗后较治疗前比较全血黏度高切、中切、低切均下降(P＜0.05),红细胞压积下降(P＜0.05).治疗组治疗后血流变学指标与对照组比较,无显著性差异(P＞0.05).结论血液黏稠度增高导致的气滞血瘀证可能是引起不孕的原因之一,通过活血理气治疗,改善微循环,增加局部组织器官血液灌注,对受孕有积极意义.     

Relationship between blood pressure and stress-prone temperament in dogs

As part of an assessment of stress during the training of guide dogs for the blind, blood pressures have been monitored in their main breeds. For this article a population of 227 Labradors, between 9 and 24 months of age, had indirect arterial blood pressures measured and means taken of five readings. They were ranked according to their pressures. Prior to the measurements, their character was independently assessed as "stress-prone" or "non-stress-prone" by their highly experienced and trained handlers. The pressure data distribution of stress-prone animals in the ranking was analysed; they were significantly more likely to be found at the high end of the blood pressure range for that population.     

Anabolic steroids and blood cell production

In the past anabolic steroids were the first-choice treatment for pancytopenic disorders that were often poorly classified. They are now superseded by other more recently developed methods of treatment--for example bone marrow transplantation and immunosuppression. This contrasts to the authors' experience, and to that of many other haematologists, who have noted anabolic steroid-induced responses in patients who were unsuitable for or unresponsive to the new treatments. Anabolic steroids did not, however, demonstrate an obvious effect in recent controlled trials involving patients with aplastic anaemia. Their use with immunosuppressive treatment is currently under investigation. Although anabolic steroids rarely reverse the course of anaemia in a myelodysplastic syndrome, even a slight haemopoietic improvement is desirable. Children with Fanconi's anaemia may benefit from a reduced transfusion requirement. Uraemic patients may experience significant side effects on standard erythropoietin (epo) treatment. There have been no controlled trials comparing epo versus anabolic steroids or epo versus epo in conjunction with anabolic steroids. Data from uncontrolled studies indicate a better response to anabolic steroids in children and females than in men. In spite of the fact that anabolic steroids have been used for almost 30 years, they should be carefully re-evaluated in scientifically controlled trials to test their efficacy and to compare them with the new treatments. Such trials, however, are impeded by the limited knowledge available with regard to pharmacological parameters and optimal treatment schedules.     

Relationship between lead mining and blood lead levels in children

The authors studied blood lead levels of 226 randomly selected children, aged 6-92 mo, who lived in either a lead-mining area or a nonmining area, and 69 controls. The authors sought to determine to what extent mining activities contributed to blood lead levels in the children. The mean blood lead levels in the study and control groups were 6.52 microg/dl and 3.43 microg/dl, respectively. The corresponding proportions of children with elevated blood lead levels were 17% and 3%. Soil and dust lead levels were up to 10 times higher in the study than the control group. Elevated blood lead levels appeared to result from exposure to both lead-mining waste and lead-based paint. Mining waste was the cause of the higher prevalence of elevated blood lead levels in these children.     

N-methyl-D-aspartic acid stimulation of vasopressin release: role in osmotic regulation and modulation by gonadal steroids

Previous experiments demonstrated that excitatory amino acids participate in the osmotic regulation of vasopressin secretion, but the specific involvement of N-methyl-D-aspartic acid (NMDA) receptors was not evaluated. This was demonstrated in the present studies. NMDA stimulated vasopressin release from perifused explants of the hypothalamo-neurohypophyseal system (HNS), and osmotic stimulation of vasopressin release was inhibited by MK-801 (10 microM) and AP5 (100 microM) NMDA receptor antagonists. The effective concentration of NMDA was dependent upon the Mg2+ concentration of the perifusate with stimulation observed at 1 microM NMDA in Mg2+-replete compared with 5 microM in low-Mg2+ medium. Previous experiments also demonstrated that estradiol and dihydrotestosterone (DHT) inhibited osmotically stimulated vasopressin secretion, and a nongenomic mechanism of action was suggested by the ability of steroids conjugated to bovine serum albumin to replicate the effect. Experiments were performed to explore the potential role of NMDA receptors in this mechanism. Estradiol (50 pg/ml) and DHT (3 ng/ml) inhibited NMDA stimulated vasopressin release in perifused HNS explants. These results suggest a role of NMDA receptors in the mediation of vasopressin secretion in osmotically stimulated release. Furthermore, estradiol and DHT may exert their inhibitory effect on osmotically stimulated vasopressin release via the NMDA receptor.     

Relationship between activity levels and circadian blood pressure variations

In 17 healthy Japanese students (14 males and 3 females) an ambulatory activity level monitoring instrument (Actigraph) was attached to the wrist for 48-hour measurement of wrist movement (with 0.01G or higher acceleration). At the same time, an ambulatory blood pressure monitoring apparatus was attached to these subjects to monitor blood pressure (BP) and heart rate (HR) every 30 minutes. Sleeping hours were calculated from the activity levels. The sleeping hours obtained by the Actigraph correlated with those judged from the diary. The correlation was better for the go-to-sleep time than for the awakening time. Activity level, HR and BP showed a similar circadian variation. Activity level differed significantly between the active daytime (4500 counts/hour) and during sleep at night (720 counts/hour). The acrophase of activity level, obtained by the cosinor method, was 235 degrees which did not significantly differ from that of BP and HR. Hourly activity levels correlated with HR and BP at corresponding hours. These results suggest that BP is affected by activity levels even if this rhythm continues to recur in bedrest.     

Percutaneous umbilical blood sampling in the management of immune thrombocytopenic purpura during pregnancy

Severe neonatal thrombocytopenia occurs in about 15% of deliveries from women with immune thrombocytopenic purpura (ITP). Conflicting data exist about the real usefulness of percutaneous umbilical blood sampling (PUBS) in evaluating the fetal platelet count. We report successful experience, using PUBS, in the management of 12 pregnant women with ITP.     

Effects of gonadal steroids on ventricular repolarization and on the response to E4031

Gonadal steroids are thought to be important determinants of gender-related differences in electrophysiology, such as the longer rate-corrected QTc intervals in women and the incidences of some clinical arrhythmias. We studied the chronic effects of gonadal steroids on cardiac action potentials (APs) using standard electrophysiological techniques. Papillary muscles were removed from the hearts of oophorectomized rabbits that had been treated with placebo, estradiol or dihydrotestosterone (DHT). The electrocardiograms of the three groups did not differ. Papillary muscle APs were studied during drive at cycle lengths of 330 to 5000 msec. The APD30 of the DHT group was significantly shorter than that of the others at cycle lengths of >500 msec. The APD90 of the estradiol group was significantly longer than that of the DHT group at cycle lengths of >1000 msec. The APD90 of the placebo group tended to be intermediate. The effects of the antiarrhythmic drug E4031 (10(-8)-10(-6) M) also were examined. E4031-induced prolongation of APD90 and magnitude of early afterdepolarizations was significantly greater in the estradiol-treated than the DHT-treated and placebo groups. In conclusion, in rabbit heart, gonadal steroids are important determinants of base-line electrophysiological properties and the proarrhythmic response to E4031.     

Relationship between blood pressure and subcortical lesions in healthy elderly people

The germinal center (GC) is an anatomic compartment found in peripheral lymphoid organs, wherein B cells undergo clonal expansion, somatic mutation, switch recombination, and reactivate immunoglobulin gene V(D)J recombination. As a result of somatic mutation, some GC B cells develop higher affinity antibodies, whereas others suffer mutations that decrease affinity, and still others may become self-reactive. It has been proposed that secondary V(D)J rearrangements in GCs might rescue B cells whose receptors are damaged by somatic mutations. Here we present evidence that mature human tonsil B cells coexpress conventional light chains and recombination associated genes, and that they extinguish recombination activating gene and terminal deoxynucleotidyl transferase expression when their receptors are cross-linked. Thus, the response of the recombinase to receptor engagement in peripheral B cells is the opposite of the response in developing B cells to the same stimulus. These observations suggest that receptor revision is a mechanism for receptor diversification that is turned off when antigen receptors are cross-linked by the cognate antigen.     

Gender difference in hypothalamic-pituitary-adrenal axis response to alcohol in the rat: activational role of gonadal steroids

Production of different recombinant proteins in baculovirus AcMNPV (BV)-infected cells may be facilitated by the availability of immunoassays to monitor active infection of Sf9 insect cells. To this end, two hybridomas secreting mouse monoclonal antibodies (mAbs) were established to different BV-related products. The proteins recognized by mAb SM22 and SM62 were easily detectable by immunoblotting and immunostaining in Sf9 cells infected with recombinant BV (rBV), but not in non-infected cells. Their production paralleled that of the recombinant proteins analyzed but was independent of the type of recombinant protein expressed. Thus, immunoassays with these mAbs allow: (1) daily monitoring of the infection occurring in small and large scale cultures of Sf9 cells using a defined rBV; (2) preliminary assessment of active rBV infection in the absence of a specific reagent for the recombinant protein and (3) single-reagent comparison of the infection achieved in Sf9 cells exposed to rBVs expressing different recombinant proteins.     

Relationship between velopharyngeal dimensions and palatal EMG during progressive hypercapnia

To examine the contribution of specific palatal muscles to velopharyngeal dimensions, we recorded electromyographic (EMG) activity in the levator veli palatini, the tensor veli palatini, and the palatoglossus while examining the velopharynx (VP) with videoendoscopy in eight awake normal adults. Simultaneous display of VP images and airflow provided precise timing of events. Video images and EMG signals were recorded during progressive hypercapnia. Every tenth breath was analyzed. For each selected breath, VP area, anteroposterior and lateral diameters, and EMG activity were determined at five points: beginning, middle, and end of inspiration and middle and end of expiration. VP measurements changed significantly during the respiratory cycle. Although maximum area was measured at end inspiration or middle expiration and minimum area at the beginning or end of the breath, respiratory-related changes in VP measurements and EMG activity were characterized by substantial inter- and intrasubject variability. This variability is similar to velopharyngeal behavior during nonrespiratory tasks and suggests that upper airway patency is determined by multiple factors.     

Assessment of platelet activation by coronary sinus blood sampling during balloon angioplasty and directional coronary atherectomy

Three markers of platelet activation (platelet-derived microparticles, fibrinogen binding and expression of P-selectin) were assessed by flow cytometry during diagnostic coronary angiography and therapeutic coronary interventions. In 24 patients undergoing diagnostic angiography, blood was collected to determine if our sampling techniques or coronary angiography caused platelet activation. Changes during diagnostic angiography were used to establish baseline values and interpret changes during coronary interventions. In 21 patients, blood samples were obtained at 5 time points during percutaneous transluminal coronary angioplasty (PTCA) (n = 17) or directional coronary atherectomy (DCA) (n = 4). During coronary interventions, mean values for the percentage of platelets expressing P-selectin or binding fibrinogen increased, but with considerable variation among patients. Individual responses for platelet activation markers in each patient were characterized using a twofold increase to indicate elevation related to the intervention. Patients were classified as having complicated or uncomplicated procedures based on the presence of acute closure, dissection, or thrombus observed by angiography. There were no differences in the percentage of elevated markers between patients with uncomplicated (12.5%) and complicated (19%) PTCA procedures. However, patients treated with DCA had more elevated markers (38%) than those treated with PTCA (15%) (p = 0.04). Our data suggest that the extent of platelet activation in individual patients cannot be predicted by common angiographic findings or complications. More markers of platelet activation were present after DCA and may reflect a greater degree of vascular trauma associated with this procedure.