Differential effects of estrogen metabolites on bone and reproductive tissues of ovariectomized rats

A total of 108 patients affected by Alport's syndrome, taken from 97 families, were enrolled in a genetic and ultrastructural study. Sixty-four families (75 patients) were X-linked, seven autosomal recessive, two autosomal dominant, five uninterpretable, and 19 sporadic. The ultrastructural features were consistent with Alport's syndrome in 66, doubtful in 20, and not significant for Alport's syndrome in 22 patients in the X-linked, sporadic, and genetically uninterpretable groups (without significant differences), as well as in the autosomal group. Mutations of the COL4A5 gene were present in 36 patients in the first three groups, without significant differences. More severe mutations were more frequently present in patients with an ultrastructural pattern consistent with Alport's syndrome. Nevertheless, there seems to be no strict correlation between mutation and ultrastructure, because a major rearrangement was found in a patient with no significant lesions, and different morphologic patterns were detected in patients Belonging to the same family. Immunohistochemical investigation into 24 patients for alpha (IV) chains showed that both alpha 3(IV) and alpha 5(IV) were lacking in the glomerular basement membrane of 13 patients (five with mutations) and were expressed in another six (three with mutations and one in the autosomal group). On the contrary, in this study the retained expression of alpha 3(IV) chain was found, despite the lack of alpha 5(IV) in the glomerular basement membrane of five patients (two with mutation). These different patterns could be related to both the type and severity of the COL4A5 mutations. All of the ultrastructural patterns were identified in all three immunohistochemical groups. Ultrastructural features and alpha 5(IV) chain production, even if an expression of a genetic mutation, do not strictly correlate. The combined use of analysis of collagen expression and electron microscopy made it possible to diagnose Alport's syndrome in 92% of the cohort, and therefore this approach is advisable. A multidisciplinary approach is recommended in the study of Alport's syndrome in an attempt to achieve a better diagnostic definition of and insight into the pathogenetic mechanisms.     

Differential effects of low- and high-dose estrogen treatments on vascular responses in female rats

In an attempt to study the mechanisms by which estrogens affect vascular responses, we utilized aortic preparations from intact and ovariectomized female rats receiving low- and high-dose subcutaneous estrogen treatments. Oil-treated, as well as male rats, served as controls. In ovariectomized females, low-dose 17-beta-estradiol injections (5 microg/kg daily for two days) affected the basal release of nitric oxide, as evaluated by concentration-related curves to superoxide dismutase and N(G)-Methyl-L-arginine acetate, which was found to be greater in 17-beta-estradiol-treated females compared to oil-treated females or males. Conversely, the nitric oxide-related vascular relaxation evoked by acetylcholine and sodium nitroprusside was unchanged. Prostacyclin production was also evaluated. Aortic rings from ovariectomized 17-beta-estradiol-treated females released significantly more prostacyclin than those from oil-treated females. These results point out a possible role for nitric oxide and prostacyclin in the vascular protection brought about by physiological levels of estrogens. When intact females were treated with high doses of ethynilestradiol (100 microg/Kg daily for one month), a component of contraceptive pills, either the basal release of nitric oxide, or acetylcholine-induced relaxation underwent a significant decrease. Likewise, the relaxant responses to sodium nitroprusside were impaired in the aortic rings obtained from ethynilestradiol-treated animals when compared to controls. Similarly, the amount of prostacyclin released from aortic tissues obtained from ethynilestradiol-treated animals was significantly reduced. These results may provide a possible explanation for the higher incidence of cardiovascular disease in women who take contraceptive preparations containing high doses of estrogens.     

Effects of dihydrotestosterone alone and combined with estrogen on bone mineral density, bone growth, and formation rates in ovariectomized rats

The combination of fast MR sequences and rapid i.v. injection of paramagnetic contrast media provides information on cerebral perfusion. MR-perfusion imaging primarily depicts the relative cerebral blood volume. The aim of this study was to test whether MR-perfusion imaging with a clinical MR scanner using a standard 2D-FLASH sequence provides clinically relevant information on patients with cerebrovascular diseases and brain tumors. Brain infarctions, lesions in cerebral microangiopathy and occlusions of the carotid artery with very poor collateralization showed definite differences in perfusion imaging compared with normal controls. However, our results show that acceleration of the imaging sequence and optimization of the contrast bolus and data processing are prerequisites for the clinical use of this method, which in principle may provide information on the absolute cerebral blood volume and even blood flow.     

3H-Estradiol uptake and retention by target tissues of light-sterilized female rats

Tissue distribution of radioactivity was studied at 2, 4 and 6 h after intravenous injection of 3H-estradiol-17beta (41.7 ng/100 g b.w.) in 12 light-sterilized and 11 control female rats ovariectomized 72 h prior to injection. Female rats were light-sterilized by exposure to continuous illumination for 82 days and, based on the duration of continuous vaginal cornification and the absence of corpora lutea at post-mortem histological examination of the ovaries, were anovulatory for at least 30 days prior to injection. Control rats were housed under conditions similar to the experimentals except that they were exposed to alternating lighting (14 h light:10 h dark). They remained ovulatory throughout the experiment. Uterine 3H-estradiol uptake and retention were significantly depressed in the light-sterilized group. There were no significant differences in 3H-estradiol uptake or retention as a result of light-sterilization in any of the other tissues studied, including anterior, middle, and posterior hypothalamus, hippocampus, amygdala, cerebrum, anterior pituitary and plasma. The failure to detecta reduction in neural 3H-estradiol uptake demonstrates that the anovulatory state can exist without a concomitant reduction in the hypothalamic estrogen binding capacity. The possibility is discussed that the decreased target tissue binding noted in various types of anovulatory animals is the result, not the cause, of altered ovarian function.     

Effect of clomiphene citrate on gonadotropin responses to LRH administration in secondary amenorrhea and oligomenorrhea

Clomiphene citrate was administered to 17 patients with either secondary amenorrhea or oligomenorrhea to study its effect on hypothalamic-pituitary response. Measurement of pulsatile gonadotropin output was accomplished utilizing samples collected every 20 minutes for 6 to 8 hours before and after clomiphene administration. Response to 100 mug synthetic luteinizing hormone releasing hormone (LRH) was measured at the end of the sampling period. Patients with polycystic ovarian disease who ovulated showed increased baseline FSH and LH, decreased peak LH, and a decrease in the percentage increase over baseline for both LH and FSH. On patient wil clinical anorexia nervosa responded to clomiphene as an estrogen, with lowered baseline LH and FSH values. Patients with resolving anorexia responded to clomiphene as an antiestrogen, with increased baseline gonadotropins, and decreased gonadotropin peak values. A patient with a surgically treated chromophobe adenoma showed no change in parameters measured before and after clomiphene administration. Baseline and pulsatile LH output appear to reflect the tonic output of gonadotropin as affected by estrogen acting in a negative feedback system, and the peak response to LRH administration, the response to the positive feedback of estrogen. Thus, LRH stimulation in clomipheneresistent patients may be of value in diagnosing the site and degree of the defect and aid in improving therapy.     

Differential expression of estrogen receptor-beta and estrogen receptor-alpha in the rat ovary

Immunohistochemical localization of two estrogen receptor (ER) subtypes, ER beta and ER alpha, was performed in neonatal, early postnatal, immature, and adult rats to determine whether ER alpha and ER beta are differentially expressed in the ovary. ER beta and ER alpha were visualized using a polyclonal anti-ER beta antibody and a monoclonal ER alpha (ID5) antibody, respectively. Postfixed frozen sections and antigen-retrieved paraffin sections of the ovary revealed nuclear ER beta immunoreactivity (IR) in granulosa cells, which was prevented when peptide-adsorbed antibody was used instead. In immature and adult rat ovaries, ER beta was expressed exclusively in nuclei of granulosa cells of primary, secondary, and mature follicles. Atretic follicle granulosa cells showed only weak or no staining. No specific nuclear ER beta IR was detected in thecal cells, luteal cells, interstitial cells, germinal epithelium, or oocytes. In neonatal rat ovary, no ER beta expression was found. In ovaries of 5- and 10-day-old rats, weak ER beta IR was observed in granulosa cells of primary and secondary follicles, but no staining was detected in the primordial follicles. ER alpha protein exhibited a differential distribution in the ovary with no detectable expression in the granulosa cells but evidence of ER alpha IR in germinal epithelium, interstitial cells, and thecal cells. In the oviduct and uterus, IR for ER alpha, but not ER beta, was found in luminal epithelium, stromal cells, muscle cells, and gland cells. Our present study demonstrates that ER beta and ER alpha proteins are expressed in distinctly different cell types in the ovary. The exclusive presence of ER beta in granulosa cells implies that this specific new subtype of ER beta mediates some effects of estrogen action in the regulation of growth and maturation of ovarian follicles.     

Differential neuronal responses to angiotensin III from the subfornical organ of normotensive and spontaneously hypertensive rats

We previously reported that chronic central administration of angiotensin III (AIII) fails to produce sustained drinking behavior in spontaneously hypertensive rats (SHR), possibly because of the development of early desensitization of the angiotensin receptors. The present study extended these findings to the cellular level, using brain-slice preparation from Wistar-Kyoto rats (WKY) and SHR, in conjunction with single-neuron recording in the subfornical organ (SFO), a target site for angiotensin II-induced drinking. We found that a majority of the SFO neurons studied (13/18 in WKY, 20/28 in SHR) responded in a dose-related manner to AIII, given in the range of 10(-6)-10(-5) M. This excitation was receptor-specific, since it was reversed by Ile7-AIII (10(-4)-10(-3) M), the selective AIII antagonist. Bestatin (10(-5)-10(-4) M), an aminopeptidase B inhibitor, did not discernibly affect basal spike frequency when delivered alone. Nevertheless, given in combination with the heptapeptide, bestatin reduced the intensity and duration of SFO neuronal response in WKY to the higher dose (10(-5) M), and in SHR to both doses (10(-6) or 10(-5) M), of AIII. These data suggest that the SFO may also be a central site of action for AIII. Moreover, prolonging the action of AIII by protecting it from being metabolized with bestatin may produce desensitization of the angiotensin receptors on SFO neurons. This was particularly so in the SHR, which are thought to be defective in the degradation of the heptapeptide in the brain.     

Differential spatiotemporal regulation of lactoferrin and progesterone receptor genes in the mouse uterus by primary estrogen, catechol estrogen, and xenoestrogen

Many xenobiotics are considered reproductive toxins because of their ability to interact with the nuclear estrogen receptors (ERalpha and ERbeta). However, there is evidence that these xenobiotics can regulate gene expression in the reproductive targets by mechanisms that do not involve these ERs. To examine this further, we compared the effects of estrogenic (o,p'-DDT [1-(o-chlorophenyl)-1-(p-chlorophenyl)2,2,2-trichloroethane] and Kepone, chlordecone) and nonestrogenic (p,p'-DDD [1,1-dichloro-2,2-bis(p-chlorophenyl)ethane], a metabolite of p,p'-DDT) xenobiotics with those of 17beta-estradiol (E2) and 4-hydroxyestradiol-17beta (4-OH-E2), a catechol metabolite of E2, on uterine expression of lactoferrin (LF) and progesterone receptor (PR). These genes are estrogen responsive in the mouse uterus. Normally, LF is expressed in the uterine epithelium, whereas PR is expressed in both the epithelium and stroma in response to estrogenic stimulation. Ovariectomized mice were injected with xenobiotics (7.5 mg/kg), E2 (10 microg/kg), 4-OH-E2 (10 microg/kg), or the vehicle (oil, 0.1 ml/mouse), and uterine tissues were processed for Northern blot and in situ hybridization. The pure antiestrogen ICI-182780 (ICI; 1 or 20 mg/kg) was used to interfere with estrogenic responses that were associated with the ERs. The results of Northern and in situ hybridization demonstrated increased uterine levels of PR and LF messenger RNAs (mRNAs) by all of these xenobiotics, but quantitatively the responses were much lower than those induced by E2 or 4-OH-E2. The results further showed that the E2-inducible epithelial LF mRNA accumulation was markedly abrogated by pretreatment with ICI (20 mg/kg). In contrast, this treatment retained the epithelial expression of PR mRNA, but down-regulated the stromal expression. In contrast, ICI had negligible effects on LF and PR mRNA responses to 4-OH-E2, indicating that this catechol estrogen exerted its effects primarily via a mechanism(s) other than the ERs. The heightened accumulation of LF mRNA in the epithelium in response to Kepone and o,p'-DDT was also severely compromised by pretreatment with ICI, but this antiestrogen had little effect on responses to p,p'-DDD. Similar to E2, Kepone increased the expression of PR mRNA in both uterine epithelium and stroma. However, pretreatment with ICI decreased stromal cell expression, whereas epithelial cell expression remained unaltered or increased. These responses were not noted in mice treated with o,p'-DDT or p,p'-DDD. Collectively, the results demonstrate that catechol estrogens or xenobiotics can alter uterine expression of estrogen-responsive genes by mechanisms that are not totally mediated by the classical nuclear ERs, and these alterations are cell type specific. We conclude that an interaction of a compound with the nuclear ERalpha and/or ERbeta is not an absolute requirement for producing specific estrogen-like effects in the reproductive target tissues.     

Differential responses to endurance training in subsarcolemmal and intermyofibrillar mitochondria

To examine the effect of endurance training (6 wk of treadmill running) on regional mitochondrial adaptations within skeletal muscle, subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria were isolated from trained and control rat hindlimb muscles. Mitochondrial oxygen consumption (VO2) was measured polarographically by using the following substrates: 1 mM pyruvate + 1 mM malate (P+M), 10 mM 2-oxoglutarate, 45 microM palmitoyl-DL-carnitine + 1 mM malate, and 10 mM glutamate. Spectrophotometric assays of cytochrome-c reductase and NAD-specific isocitrate dehydrogenase (IDH) activity were also performed. Maximal (state III) and resting (state IV) VO2 were lower in SS than in IMF mitochondria in both trained and control groups. In SS mitochondria, training elicited significant 36 and 20% increases in state III VO2 with P+M and glutamate, respectively. In IMF mitochondria, training resulted in a smaller (20%), yet significant, increase in state III VO2 with P+M as a substrate, whereas state III VO2 increased 33 and 27% with 2-oxoglutarate and palmitoyl-DL-carnitine + malate, respectively. Within groups, cytochrome-c reductase and IDH activities were lower in SS when compared with IMF mitochondria. Training increased succinate-cytochrome-c reductase in both SS (30%) and IMF mitochondria (28%). IDH activity increased 32% in the trained IMF but remained unchanged in SS mitochondria. We conclude that endurance training promotes substantial changes in protein stoichiometry and composition of both SS and IMF mitochondria.     

Localization of estrogen receptor-alpha in human and rabbit skeletal tissues

Estrogen is essential for the development and maintenance of optimal bone mass in women and men, and acts through activation of estrogen receptors (ER). We have examined the pathways of estrogen action on the skeleton by seeking to localize the "classical" estrogen receptor, ER alpha, to particular cells to test the hypotheses that 1) estrogen directly influences growth plate chondrocytes; and 2) estrogen has a principal action on bone tissue via osteoblasts. ER alpha messenger ribonucleic acid (mRNA) was localized by in situ hybridization in human specimens from five males (11-15 yr old), two females (9 and 11 yr old), and three growing rabbits. In all of the human material examined, ER alpha mRNA was consistently identified in chondrocytes. In all of the rabbit tissue studied, ER alpha mRNA was localized in chondrocytes of the growth plate and the subarticular epiphyseal growth center. ER alpha mRNA signals were readily observed in both active osteoblasts and lining cells on trabecular surfaces of all samples. No clear evidence of positive staining was detectable in osteoclasts or osteocytes in either species. The distribution of ER alpha mRNA coincided with immunolocalization of the ER protein in the human specimens. These data suggest a direct action of estrogen on growth plate chondrocytes that may affect longitudinal growth and subsequent fusion of the growth plate and also on osteoblasts to affect bone formation at trabecular sites.     

Differential responses to male and female depressive reactions.

Suggests that the commonly reported preponderance of female over male depression in incidence and prevalence studies requires further analysis. One explanation is that the social consequences of expression of depressive symptomatology are different for males and females. A comparison of 157 male and 189 female undergraduates' reactions to male and female case histories of common reactions to stress confirmed the hypothesis. Depression elicited more rejection of males than of females, and the sex difference in rejection of depression was more pronounced than for anxiety or flat affect-detached responses. A discriminant analysis suggested that depressed males are especially likely to be perceived as impaired in role functioning as compared with depressed females. Results suggest that depressed males are not rejected for expression of emotionality as such. Speculations about the causes and consequences of differential rejection of depression are noted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cardiac responses to moderate training in rats

Left ventricular (LV) performance was studied in 30 rats conditioned by swimming and in 27 sedentary controls. Hearts were studied in the open chest both during sinus rhythm and during atrial pacing. Afterload was increased by occlusion of the aorta. Sinus rates were 328 beats/min in sedentary and 300 in conditioned animals (P less than 0.01). During ejection (E), peak left ventricular systolic pressure (PLVSP) and maximum LV dP/dt were significantly higher in conditioned than in sedentary animals. When data from hearts matched for similar heart rates were compared, increased LV performance was still seen during aortic obstruction in conditioned animals. Performance at pacing rates up to 400 beats/min was similar in hearts from conditioned and sedentary animals. At pacing rates above 400 beats/min cardiac performance was less in sedentary than in the conditioned animals. These data illustrate that although base-line cardiac performance may be the same in rats conditioned by a moderate swimming program and in sedentary animals, cardiac reserve is improved by the swimming program.     

HuR, a novel target of anti-Hu antibodies, is expressed in non-neural tissues

Paraneoplastic encephalomyelitis (PEM) is characterized by a diverse set of clinical signs that are limited to the nervous system. The serologic hallmark of PEM is the presence of circulating autoantibodies, collectively referred to as 'anti-Hu,' which immunoreact specifically with members of the Elav protein family. Until recently, the ELAV antigens were only detected in neurons, thus strongly supporting a role for anti-Hu antibodies in the selective neural tissue injury in PEM. The identification of HuR, however, a new member with a broad, non-neural pattern of RNA expression, raises several fundamental questions regarding PEM. First, why are non-neural tissues spared in PEM? Second, why is PEM predominantly associated with neuroendocrine tumors? To begin addressing these questions, we sought to determine whether the antibody response to HuR differs from the neural-specific counterparts in patients with PEM, and to characterize the protein expression pattern of this novel antigen in peripheral tissues and tumors. Using sera from 11 patients with Hu-positive PEM, we found that the majority of samples (73%) were weakly or non-reactive for recombinant HuR on Western blot, in contrast to consistently strong immunoreactivity with the neural-specific members HuD and Hel-N1. We also demonstrate that HuR is expressed at the protein level in both non-neural tissues and non-neuroendocrine tumors. These findings suggest that immunoreactive differences among Elav family members may contribute to the neural-restrictive pattern of tissue injury in patients with PEM.     

Renal, intestinal, and adrenal responses to sodium loading in Dahl-Iwai salt-sensitive and salt-resistant rats

Following the introduction of an improved surveillance system for infectious intestinal disease outbreaks in England and Wales, the Public Health Laboratory Service Communicable Disease Surveillance Centre received reports of 26 outbreaks between 1 January 1992 and 31 December 1995 in which there was evidence for waterborne transmission of infection. In these 26 outbreaks, 1756 laboratory confirmed cases were identified of whom 69 (4%) were admitted to hospital. In 19 outbreaks, illness was associated with the consumption of drinking water from public supplies (10 outbreaks) or private supplies (9 outbreaks). The largest outbreak consisted of 575 cases. In 4 of the remaining 7 outbreaks, illness was associated with exposure to swimming pool water. Cryptosporidium was identified as the probable causative organism in all 14 outbreaks associated with public water supplies and swimming pools. Campylobacter was responsible for most outbreaks associated with private water supplies. This review confirms a continuing risk of cryptosporidiosis from chlorinated water supplies in England and Wales, and reinforces governmental advice to water utilities that water treatment processes should be rigorously applied to ensure effective particle removal. High standards of surveillance are important for prompt recognition of outbreaks and institution of control measures. As microbiological evidence of water contamination may be absent or insufficient to implicate a particular water supply, a high standard of epidemiological investigation is recommended in all outbreaks of suspected waterborne disease.     

Somatostatin immunoreactivity in bone and joint tissues

Using immunoelectron microscopy we have investigated the presence of somatostatin in normal bone and joint tissues. We observed somatostatin labeling in the myelinated nerve fibers of the periosteum, the bone marrow cells and in the mature bone matrix but only slightly in the synovial cells. Quantification of somatostatin in bone tissue by radioimmunoassay showed highest levels in bone marrow followed by periosteum and cortical bone. These findings suggest a role for somatostatin in bone and joint physiology.     

Interrelationship of magnesium and estrogen in cardiovascular and bone disorders, eclampsia, migraine and premenstrual syndrome

The anticonvulsive and antihypertensive values of magnesium (Mg) in eclampsia, and its antiarrhythmic applications in a variety of cardiac diseases, have caused Mg to be considered only for parenteral administration by many physicians. In contrast, nutritionists have long recognized Mg as an essential nutrient, because severe deficiencies elicit neuromuscular manifestations similar to those justifying its use in eclampsia. More recently, this element has been used to favorably influence latent tetany with and without thrombotic complications, to delay preterm birth, to influence premenstrual syndrome, and to ameliorate migraine headaches. Most of these disorders exclusively or largely afflict women. The lesions of arteries and heart caused by experimental Mg deficiency have been well documented and may contribute to human cardiovascular disease. Estrogen's enhancement of Mg utilization and uptake by soft tissues and bone may explain resistance of young women to heart disease and osteoporosis, as well as increased prevalence of these diseases when estrogen secretion ceases. However, estrogen-induced shifts of Mg can be deleterious when estrogen levels are high and Mg intake is suboptimal. The resultant lowering of blood Mg can increase the Ca/Mg ratio, thus favoring coagulation. With Ca supplementation in the face of commonly low Mg intake, risk of thrombosis increases.     

Low-selenium diet, bone, and articular cartilage in rats

The pathophysiology of secondary osteoarthritis remains largely obscure. Our attention has been drawn to Kashin-Beck disease (KBD), which has been attributed to Se deficiency. To obtain information regarding the prevention, prediction of progression, and treatment of this condition, we performed histological and biochemical studies on bone and articular cartilage specimens obtained from rats fed a low-Se diet. A low-Se diet was prepared and fed to Wistar rats for 3-11 mo, after which the rats were killed under general anesthesia, and their articular cartilages were studied microscopically and electron microscopically. The bone mineral density (BMD) of the femur was determined by the microdensitometry method and ash weight. In addition, serum Se, Ca, P, Alk Phos, T3, T4, and urinary Se were measured. In the low-Se group, impaired weight gain was observed from the 5th mo, and head alopecia was found in 60% of the animals. Microscopically, no clear changes in the articular chondrocytes were apparent, whereas with the electron microscope, chondrocytes in the deep layer showed degeneration of nuclei and endoplasmic reticular ballooning. From the 5th mo, a decrease in BMD (ash weight) was noted. Serum Se concentrations, alkaline phosphatase activity, and urine Se concentrations were decreased in the Se-deficient rats, whereas serum Ca, P, T3, and T4 values did not differ from those of a control group. Also, a decrease in sulfotransferase activity, which is involved in transfer in the process of synthesis of glycosaminoglycan, which is a proteoglycan carbohydrate chain, was found.(ABSTRACT TRUNCATED AT 250 WORDS)     

Exogenous estrogen may exacerbate thrombophilia, impair bone healing and contribute to development of chronic facial pain

Humoral and cellular responses to Schistosoma bovis antigens have been evaluated over a period of 11 weeks in mice exposed to S. bovis cercariae and data analysed in the context of the parasitic parameters (worm and egg loads) recorded at days 30, 60 and 80 of the ongoing infection. Results revealed a decrease of worm burden, particularly marked for female worms, between day 60 and day 80 of infection suggesting a higher susceptibility of female schistosomes to attrition mechanisms. The B-cell response, studied by measuring the production of different isotypes, was directed against different stage specific antigens, with a predominance of IgG1 antibodies associated with a significant increase of IgA and IgE antibodies after egg deposition. The T-cell response, assessed after in vitro stimulation of splenocytes, showed a predominant production of Th-2 cytokines (IL-4, IL-5 and IL-10) occurring after egg laying. Interestingly in contrast to S. mansoni infection the Th-2 polarization did not seem to be exclusively triggered by egg-associated antigens since significant amounts of IL-10 were produced after stimulation with adult worm antigen preparation (SWAP) before the beginning of egg deposition.