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1.
Plasma concentraption changes in luteinizing hormone (LH) and follicle stimulation hormone (FSH) following elctrochemical stimulation (ECS) of the medial preoptic area (MPOA) or dorsal anterior hypothalamic area (DAHA) of estrogen-or androgen-sterilized rats were compared with normal proestrous rats in which spontaneous gonadotropin surges had been blocked with Nembutal (control). ECS of control rats, AST, and ESR provoked marked increases in FSH by 120 minutes and peak levels by 180 minutes poststimulation. No differenses were seen when ESR of ASR plasma levels were compared with control values or to each other (ESR vs. ASR). DAHA-ECS did not provoke a marked LH rise in ASR and ESR. MPOA-ECS of control, ASR, and ESR resulted in the release of LH and FSH. FSH peaked in all groups at 240 minutes but at 120 and 180 minutes poststimulation plasma FSH levels were greater in ASR and ESR than controls. FSH in ESR was significantly higher (p. 05) at 120 and 240 minutes poststimulation. LH was elevated in all groups following MPOA-EDS but in ESR markedly greater LH levels were obtained at 60 and 180 minutes compared with controls or ASR. Preoptic stimulation of progesterone-treated ASR (P-ASR) did not induce greater release of FSH than in control, ASR, ESR, or P-ESR. Stimulation of P-ASR resulted in greater plasma LH rise by 60 minutes which was greater than ASR, P-ASR, ESR, or controls, followed by decreased levels to baseline in P-ESR. MPOA-ECS controls ovulated (8-13 eggs) whereas neither ASR nor ESR Fallopian tubes contained eggs the following morning. No DAHA-stimulated groups ovulated. All P-ASR but no P-ESR ovulated after MPOA-ECS. It is concluded that while exposure of neonatal female rats to estrogen renders them more sensitive than ASR to preoptic stimulation, the ovaries of these amimals are much less responsive to the gonadotropin released into plasma than are those of ASR or normal rats.  相似文献   

2.
Immunization of rats with enriched murine specific T-suppressors (STS) permitted obtaining the antisuppressor serum (ASS) which selectively inactivated in vitro the capacity of the STS to inhibit the proliferation of T-lymphocytes in a mixed lymphocyte culture in response to allo-antigens. Two opposite effects of the ASS in vivo were demonstrated: elimination of T-suppressors (on ASS administration 4 days after immunization) and stimulation of their formation (on ASS administration before immunization or to non-immunized mice). It is assumed that the two opposite effects of the ASS in vivo are caused by two different types of antibodies to unidentified markers of STS to an antigen of differentiated STS and to an antigen expressed on their precursors.  相似文献   

3.
酸性硫酸盐土中的硫及其形态演变探讨   总被引:3,自引:0,他引:3  
钟继洪 《生态学杂志》2003,22(5):98-101
研究了酸性硫酸盐土中S及其形态演变。结果表明,酸性硫酸盐土S含量高,以无机态为主;S积累和S形态演变与酸性硫酸盐土形成、发育与利用密切相关。与红树林盐渍沼泽土(潜在酸性硫酸盐土)比较,酸性硫酸盐水稻土黄钾铁矾S含量较高,但FeS2含量较低。酸性硫酸盐水稻土S形态剖面分布明显,其氧化层的黄钾铁矾S含量较高,pH值较低;其还原层的FeS2含量较高。防治酸害是酸性硫酸盐土持续利用要解决的关键问题。  相似文献   

4.
A special herbal tea has been used to treat clomiphene-resistant anovulatory disease and obesity effectively, especially in polycystic ovary syndrome (PCOS) cases with hyperinsulinemia. The effect of the herbal tea on obesity and anovulation was investigated in androgen-sterilized rats (ASR). The ASR model was established by subcutaneous injection of 1.25 mg testosterone propionate to Sprague-Dawley female rats at the age of 9 days. Rats were sacrificed around 112 days of age. ASR manifested with PCO, anovulation, high food intake, elevated body weight, and obesity. Immunocytochemistry demonstrated that estrogen receptors (ER) were predominantly distributed in the cytoplasm of neuropeptide Y (NPY)-containing neurons in the preoptic area (POA), and the coexpression was also found in the nuclei and fibers of NPY-synthesizing neurons in the arcuate nucleus (ARC). Compared with that in normal control rats, NPY expression was increased, the numbers of ER in hypothalamic ARC-median eminence (ME) decreased, gonadotropin-releasing hormone (GnRH) levels in ME was decreased, serum estrogen (E2) and leptin were elevated, and follicular stimulating hormone (FSH) and luteinizing hormone (LH) levels were reduced significantly in ASR. Significantly negative correlations between NPY and ER or GnRH, and between leptin and FSH or LH were observed. A positive correlation existed between serum leptin and body weight. These metabolic-endocrine changes in ASR were normalized after feeding the herbal tea. Both obesity and hypogonadotropin were expressed in ASR. The abnormal ovarian hormone milieu (elevated E2 levels) may have enhanced NPY expression and resulted in less GnRH and gonadotropin secretion. The herbal tea reduced body weight and induced ovulation in ASR.  相似文献   

5.
Hepatic ischaemia/reperfusion (I/R), a major cause of liver damage associated with multiple trauma, haemorrhagic and septic shock, and liver transplantation, contributes significantly to multiple organ failure. Development of novel sensitive biomarkers that detect early stages of liver damage is vital for effective management and treatment of ischaemic liver injury. By using high-throughput immunoblotting and cation-anion exchange chromatography/reversed-phase liquid chromatography-tandem mass-spectrometry, we identified several hepatic proteins, including argininosuccinate synthase (ASS) and estrogen sulfotransferase (EST-1), which were degraded in the liver and rapidly released into circulation during I/R injury. ASS accumulated in serum within 10 min, reached a steady state at 30 min, and persisted up until 3 h after reperfusion following 30 min of total hepatic ischaemia. EST-1 appeared rapidly in blood and attained maximum within 1 hour followed by a decline at 3 h of reperfusion. No ASS or EST-1 protein was detected in serum of control or sham operated rats. ASS and EST-1 exhibited greater sensitivity and specificity toward I/R liver injury as compared with alanine aminotransferase (ALT), an established marker of hepatocellular necrosis. In contrast, serum ASS and EST-1 were undetectable in rats with chronic alcoholic liver disease, while the levels of ALT protein were significantly increased. In addition, ASS, but not EST-1 or ALT accumulated in blood only 6 h after treatment with hepatotoxic combination of lipopolysaccharide and D-galactosamine. These data demonstrate the utility of ASS and EST-1 as novel sensitive and specific biomarkers of acute liver ischaemic injury for prospective clinical studies.  相似文献   

6.
Hepatic ischaemia/reperfusion (I/R), a major cause of liver damage associated with multiple trauma, haemorrhagic and septic shock, and liver transplantation, contributes significantly to multiple organ failure. Development of novel sensitive biomarkers that detect early stages of liver damage is vital for effective management and treatment of ischaemic liver injury. By using high-throughput immunoblotting and cation–anion exchange chromatography/reversed-phase liquid chromatography-tandem mass-spectrometry, we identified several hepatic proteins, including argininosuccinate synthase (ASS) and estrogen sulfotransferase (EST-1), which were degraded in the liver and rapidly released into circulation during I/R injury. ASS accumulated in serum within 10 min, reached a steady state at 30 min, and persisted up until 3 h after reperfusion following 30 min of total hepatic ischaemia. EST-1 appeared rapidly in blood and attained maximum within 1 hour followed by a decline at 3 h of reperfusion. No ASS or EST-1 protein was detected in serum of control or sham operated rats. ASS and EST-1 exhibited greater sensitivity and specificity toward I/R liver injury as compared with alanine aminotransferase (ALT), an established marker of hepatocellular necrosis. In contrast, serum ASS and EST-1 were undetectable in rats with chronic alcoholic liver disease, while the levels of ALT protein were significantly increased. In addition, ASS, but not EST-1 or ALT accumulated in blood only 6 h after treatment with hepatotoxic combination of lipopolysaccharide and D-galactosamine. These data demonstrate the utility of ASS and EST-1 as novel sensitive and specific biomarkers of acute liver ischaemic injury for prospective clinical studies.  相似文献   

7.
The field potential and temperature of the cerebral cortex were studied in right-handed, left-handed, and ambidextrous rats. Temperature asymmetry of the cerebral hemispheres was revealed, which proved to differ in rats with different types of interhemispheric asymmetry: the interhemispheric temperature gradient was maximal in left-handed rats, minimal in right-handed rats, and intermediate in ambidextrous rats. Both parameters of energy metabolism (field potential and temperature of the cerebral cortex) correlated with one another, and the structure of these statistically significant correlations was different in right-handed, left-handed, and ambidextrous rats. It is suggested that the previously known types of interhemispheric asymmetry—biochemical, neurophysiological, and organoelement—are based on differences in the intensity of energy-consuming processes in the cerebral hemispheres.  相似文献   

8.
By means of transmission electron microscopy, the age-related changes in axospinous (ASS) and axodendritic (ADS) synapses in the dorsal part of the rostral neostriatum in two groups of Wistar rats: young (3-month-old), and senescent (25-month-old) were examined. The changes in different parameters, characterizing the ASS and ADS: synaptic density (SD), number of synaptic vesicles (SV), number of synaptic contact zone (SCZ), and number of dendritic spines, bearing synapses (DS) were investigated morphometrically. The SD of the ASS decreased significantly during aging, but the SD of the ADS did not changed significantly. The mean area of the synaptic boutons increased significantly during aging in two types of synapses. The mean number of vesicles per synaptic bouton increased, but the number of vesicles per microm2 of synaptic bouton, and per microm3 of the neuropil decreased. The mean SCZ length increased in both types of synapses. The total SCZ length per 1000 microm2 of the neuropil, and the total area of the SCZ per 1000 microm3 of the neuropil decreased in ASS, but the same parameters of the ADS did not changed significantly. The mean number of synaptic DS per 1000 microm2 of the neropil decreased during aging, but the mean area of the synaptic DS increased. The present results support the hypothesis that the synaptic contacts change significantly during aging, and the ASS are more vulnerable during aging than the ADS.  相似文献   

9.
It has been suggested that the lateralization of the human brain underlies hemispheric specialization and that it can be observed also on a biochemical level. Biochemical laterality appears to be a basis of volumetric or functional asymmetry but direct relationships among them are still unclear. Moreover, age-related differences between the right and left hemispheres are not well documented in various rat strains. In the current study, biochemical markers sensitive to Alzheimer disease (activities of high-affinity choline uptake and of nitric oxide synthases, expression of 17β-hydroxysteroid dehydrogenase type 10) were estimated in both hemispheres of young and old male Wistar/Long Evans rats. Our experiments indicate (1) differences in some biochemical markers between young Wistar and Long Evans rats (the activities of endothelial nitric oxide synthase are higher in Long Evans and those of citrate synthase in Wistar rats), (2) more similar brain asymmetry of healthy human/young Wistar brains when compared to those of young Long Evans, (3) the decrease in asymmetry of the physiologically left/right lateralized biomarker during aging (the activity of the high-affinity choline uptake decreases more markedly in the left side of old Wistar rats) in accordance with the HAROLD model, (4) the age-related shift to reversed left/right asymmetry of the physiologically right/left lateralized biomarker (the activity of inducible nitric oxide synthase increases especially in the left side of old Long Evans rats), and finally (5) age-related differences in physiologically unlateralized biomarkers between Wistar and Long Evans rats (changes in the activities of neural/endothelial nitric oxide synthases or in expression of 17β-hydroxysteroid dehydrogenase type 10 are more asymmetrical in old Wistar when compared to rather bilateral alterations of old Long Evans animals). It seems that the physiological lateralization of the human or rat brains on a biochemical level and their age-related alterations are dependent on biomarker type/function. By our opinion, it is difficult, perhaps impossible, to make one simple universal model, at least on a biochemical level. Since lateral analyses are of sufficient sensitivity to reveal subtle links, we recommend using Wistar rather than Long Evans rats in modeling of diseases accompanied by alterations in brain asymmetry.  相似文献   

10.
Laminar shear stress (LSS) is known to increase endothelial nitric oxide (NO) production, which is essential for vascular health, through expression and activation of nitric oxide synthase 3 (NOS3). Recent studies demonstrated that LSS also increases the expression of argininosuccinate synthetase 1 (ASS1) that regulates the provision of L-arginine, the substrate of NOS3. It was thus hypothesized that ASS1 might contribute to vascular health by enhancing NO production in response to LSS. This hypothesis was pursued in the present study by modulating NOS3 and ASS1 levels in cultured endothelial cells. Exogenous expression of either NOS3 or ASS1 in human umbilical vein endothelial cells increased NO production and decreased monocyte adhesion stimulated by tumor necrosis factor-α (TNF-α). The latter effect of overexpressed ASS1 was reduced when human umbilical vein endothelial cells were co-treated with small interfering RNAs (siRNAs) for ASS1 or NOS3. SiRNAs of NOS3 and ASS1 attenuated the increase of NO production in human aortic endothelial cells stimulated by LSS (12 dynes·cm(-2)) for 24 h. LSS inhibited monocyte adhesion to human aortic endothelial cells stimulated by TNF-α, but this effect of LSS was abrogated by siRNAs of NOS3 and ASS1 that recovered the expression of vascular cell adhesion molecule-1. The current study suggests that the expression of ASS1 harmonized with that of NOS3 may be important for the optimized endothelial NO production and the prevention of the inflammatory monocyte adhesion to endothelial cells.  相似文献   

11.
Rats allocated to groups by the method of "emotional resonance": rats which did and did not escape crying of a partner (A- and E-groups, respectively). Unit activity in the right and left prefrontal brain cortex (PFC) was recorded in these rats. The recorded neurons neurons were divided in two groups according to their reaction to a change in the level of food motivation. The so-called D-neurons decreased their activity after feeding of animals after a 24-hour food deprivation and the other group (I-neurons) increased its firing rate rate in this situation. It was shown that hemispheric distributions of D- and I-neurons are different in selected rat groups. In E-rats the I-neurons substantially predominated in the left hemisphere, whereas the D-neurons were more frequently recorded in the right one. No such asymmetry was observed in A-group of rats. During intracranial stimulation of emotionally positive brain structures I-neurons increased their firing rate, predominantly, in the left hemisphere, whereas during intracranial emotionally negative stimulation activation of the D-neurons predominated at the right. Features of the observed functional interhemispheric asymmetry of prefrontal cortex in A- and E-groups of rats were explained by differences in the interaction between hemispheres and dissimilar activation control.  相似文献   

12.
Incidence data from the population cancer registry of Cotonou (Benin) for the three year period 2014–2016 are presented.1086 cancer cases were recorded, 608 cases (56.0%) in women (corresponding to an age standardized incidence rate (ASR) of 78.4 per 100,000) and 478 cases (44.0%) in men (ASR 91.8 per 100,000).Breast and cervical cancer accounted for 49.2% of all cancers in women. Breast cancer (ASR 22.6 per 100,000) was more common than cervical cancer (ASR 14.9 per 100,000) and the mean age of cases was lower. The incidence of prostate cancer (one quarter of all cancers in men), 30.5 per 100,000, was similar to that in other West African registries. Cancers of the liver and digestive tract were also relatively common in both sexes.These are the first data on cancer incidence in Benin, and will be invaluable for the development and evaluation of the National Cancer Control plan.  相似文献   

13.
Virulence factors for Aeromonas salmonicida subsp. salmonicida (ASS) strains isolated from cultured turbot Psetta maxima L. are unknown with regard to this host. The presence of virulence genes associated with different stages of ASS infection in salmonids (vapA, tapA, fla, ascV, ascC, aexT, satA and aspA) was analysed using a polymerase chain reaction (PCR) technique in ASS strains isolated from turbot. Other ASS strains isolated from salmonids and environmental A. salmonicida (AS) strains were included for comparison. The presence of the genes was evaluated with respect to ASS virulence in turbot based on intraperitoneal and bath challenges. The genetic profile, including all of the genes studied, that was linked to virulent behaviour after intraperitoneal challenge was significantly more frequent in strains isolated from turbot than in those from salmonids or the environment. The data prove that it is not possible to predict the virulence of ASS in turbot based only on the presence of all genes tested. Moreover, the combined PCR results of vapA, aexT, ascV and ascC were useful for separating most of the ASS from environmental A. salmonicida strains. An association between virulence or genetic profile and the geographical or facility origin of the strains was not found.  相似文献   

14.
Deficiency of argininosuccinate synthetase (ASS) causes citrullinemia in human beings. Type II citrullinemia is found in most patients with adult-onset citrullinemia in Japan, and ASS deficiency is found specifically in the liver. Previous studies have shown that the decrease of hepatic ASS activity is caused by a decrease in enzyme protein with normal kinetic properties and that there were no apparent abnormalities in the amount, translational activity, and gross structure of hepatic ASS mRNA. In the present work, we show by sequencing analysis that there was no mutation in the ASS mRNA from two patients with type II citrullinemia. We also report RFLP analysis of a consanguineous family with type II citrullinemia, by using three DNA polymorphisms located within the ASS gene locus. In spite of having consanguineous parents, the patient was not a homozygous haplotype for the ASS gene. The RFLP analysis of 16 affected patients from consanguineous parents showed that 5 of 16 patients had the heterozygous pattern for one of the three DNA probes and that the frequency of the heterozygous haplotype was not different from the control frequency. These results suggest that the primary defect of type II citrullinemia is not within the ASS gene locus.  相似文献   

15.
Convict cichlid fish (Archocentrus nigrofasciatus) are one of the few monogamous species where the female appears more colorful than the male. We examined whether this sexual dimorphism was reflected in a female-biased actual sex ratio (ASR) and whether convict cichlid females would exhibit behavioral traits typified in monogamous males when they possessed the extravagant colors and/or morphology. Our field observations revealed that females are marginally, but not significantly, more abundant than males but they did initiate more intersexual social interactions (i.e. approach behavior) than males. They also showed more intrasexual aggression. Furthermore, males more commonly chased females rather than vice versa. Our laboratory experiment also indicated that differences in intrasexual aggression were not related to differences in the ASR but did appear with the addition of a breeding site. Thus, while intrasexual competition was more frequently observed between females in the field it was probably related to the availability of breeding sites rather than our estimates of the ASR.  相似文献   

16.
Nakazawa T 《PloS one》2011,6(2):e14667
It has been suggested that when juveniles and adults use different resources or habitats, alternative stable states (ASS) may exist in systems coupled by an ontogenetic niche shift. However, mainly the simplest system, i.e., the one-consumer-two-resource system, has been studied previously, and little is known about the development of ASS existing in more complex systems. Here, I theoretically investigated the development of ASS caused by an ontogenetic niche shift in the presence of multiple resource use. I considered three independent scenarios; (i) additional resources, (ii) multiple habitats, and (iii) interstage resource sharing. The model analyses illustrate that relative balance between the total resource availability in the juvenile and adult habitats is crucial for the development of ASS. This balance is determined by factors such as local habitat productivity, subsidy inputs, colonization area, and foraging mobility. Furthermore, it is also shown that interstage resource sharing generally suppresses ASS. These results suggest that the anthropogenic impacts of habitat modifications (e.g., fragmentation and destruction) or interaction modifications (e.g., changes in ontogeny and foraging behavior) propagate through space and may cause or prevent regime shifts in the regional community structure.  相似文献   

17.
Asymmetry of movement direction was found in Wistar rats at establishing of motor alimentary conditioned reflex to simultaneously presented visual stimuli. In the course of learning the asymmetry weakened on the whole, but some individuals retained right- or left side preference. The analysis of asymmetry change before and after unilateral cortical inactivation revealed a special role of right hemisphere influences for the formation of right-side preference and of the left hemisphere--for the choice of the left direction. The lack of asymmetry was observed at the presence of the influences from the left hemisphere cortex depressing ipsilateral nigro-striate system and activating the contralateral one. Influences of the cortex of both hemispheres reduce the absolute value of the asymmetry coefficient; the left hemisphere has a special significance for manifestation of temporal asymmetry parameters. Photic interference is a factor modulating the asymmetry. It reduces the right hemisphere activity more than that of the left one; it intensifies right hemisphere influences, contributes to the involvement of the transcallosal conduction channel in the formation of spatial-motor asymmetry.  相似文献   

18.
Plasma albumin is well known to decrease in response to inflammation. The rate of albumin synthesis from both liver and plasma was measured in vivo by use of a large dose of L-[(2)H(3)-(14)C]valine in rats injected intravenously with live Escherichia coli and in pair-fed control rats during the acute-phase period (2 days postinfection). The plasma albumin concentration was reduced by 50% in infected rats compared with pair-fed animals. Infection induced a fall in both liver albumin mRNA levels and albumin synthesis relative to total liver protein synthesis. However, absolute liver albumin synthesis rate (ASR) was not affected by infection. In plasma, albumin fractional synthesis rate was increased by 50% in infected animals compared with pair-fed animals. The albumin ASR estimated in the plasma was similar in the two groups. These results suggest that hypoalbuminemia is not due to reduced albumin synthesis during sepsis. Moreover, liver and plasma albumin ASR were similar. Therefore, albumin synthesis measured in the plasma is a good indicator of liver albumin synthesis.  相似文献   

19.
Direct experimental evidence for alternative stable states: a review   总被引:13,自引:0,他引:13  
A large number of studies have presented empirical arguments for the existence of alternative stable states (ASS) in a wide range of ecological systems. However, most of these studies have used non-manipulative, indirect methods, which findings remain open for alternative explanations. Here, we review the direct evidence for ASS resulting from manipulation experiments. We distinguish four conclusive experimental approaches which test for predictions made by the hysteresis effect: (1) discontinuity in the response to an environmental driving parameter, (2) lack of recovery potential after a perturbation, (3) divergence due to different initial conditions and (4) random divergence. Based on an extensive literature search we found 35 corresponding experiments. We assessed the ecological stability of the reported contrasting states using the minimum turnover of individuals in terms of life span and classified the studies according to 4 categories: (1) experimental system, (2) habitat type, (3) involved organisms and (4) theoretical framework. 13 experiments have directly demonstrated the existence of alternative stable states while 8 showed the absence of ASS in other cases. 14 experiments did not fulfil the requirements of a conclusive test, mostly because they applied a too short time scale. We found a bias towards laboratory experiments compared to field experiments in demonstrating bistability. There was no clear pattern of the distribution of ASS over categories. The absence of ASS in 38% of the tested systems indicates that ASS are just one possibility of how ecological systems can behave. The relevance of the concept of ASS for natural systems is discussed, in particular under consideration of the observed laboratory bias, perturbation frequency and variable environments. It is argued, that even for a permanently transient system, alternative attractors may still be of relevance.  相似文献   

20.
This study examines the effects of somatocrinin (GRF) and somatostatin antiserum (ASS), jointly and separately on gastric and duodenal growth. 24-day-old rats received twice daily SC injections of saline or GRF (4 and 20 micrograms X kg-1) for 14 days. ASS was given IP every 2 days. Alone, GRF increased gastric fundus weight concomitantly with DNA, RNA and protein contents producing hyperplasia and hypertrophy within this gland. Alone, ASS increased RNA and protein cellular concentrations. Joint ASS and GRF treatment stabilized the weight and protein content of the fundus, while reducing RNA contents as well as RNA and protein concentrations. GRF alone caused significant increments in duodenal weight and protein content suggesting cellular hypertrophy. Growth hormone, gastrin, cholecystokinin and secretin may be considered as putative mediators of these trophic effects.  相似文献   

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