首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Prostaglandins have long been thought to play important roles in the mechanism of parturition. Here we review the involvement of prostaglandins in myometrial and cervical functions with emphasis on human labor and birth. In addition, the cellular sources of prostaglandins as well as their interactions with various other endocrine, paracrine and physical factors, such as oxytocin, corticotropin releasing hormone, nitric oxide, platelet activating factor, cytokines, endothelin and stretch are also addressed together with their potential role in the molecular reorganization of cervical structure associated with labor and delivery. Finally, the premier role of progesterone in pregnancy maintenance and parturition is juxtaposed with the proposed "fine-tuning", modulatory role of prostaglandins and the above listed factors in the regulation of parturition.  相似文献   

2.
A cytochemical study using a lead precipitation technique has been made of the distribution of adenosine triphosphatase (ATPase) in mature and differentiating phloem and xylem cells of Nicotiana tabacum and Pisum sativum. The sites of ATPase localization in tobacco phloem were the plasma membrane, endoplasmic reticulum, mitochondria, dictyosomes, plasmodesmata, and the dispersed P proteins of mature sieve elements. In pea phloem sieve elements ATPase was localized in the endoplasmic reticulum, but was not associated with the P proteins or plasma membranes at any stage of their differentiation. In pea transfer cells ATPase activity was associated with the endoplasmic reticulum at all stages of their differentiation and with the plasma membrane of transfer cells that had formed wall ingrowths. In xylem cells of both tobacco and pea the patterns of ATPase activity was similar. At early stages of differentiation ATPase activity was associated with the plasma membrane and the endoplasmic reticulum. At intermediate stages of differentiation ATPase activity continued to be associated with the endoplasmic reticulum, but was no longer associated with the plasma membrane. At later stages of xylem element differentiation ATPase activity was associated with disintegrating organelles and with the hydrolyzing cell walls.  相似文献   

3.
In 16 adult cats with electrolytically destructed external and internal parts of the globus pallidus and in 8 cats with destructed putamen direct strio-pallido-hypothalamic and strio-pallido-subthalamic pathways have been studied. Degeneration of the axonal preterminals and terminals have been examined in preparations treated after Nauta--Gygax, Nauta--Laidlow, Finck--Heimer with simultaneous additional staining of the nuclei with cresyl violet after Kawamura--Niimi. Direct pallido- and putamen-hypothalamic pathways to nuclei of the grey tubercle, posterior and lateral nuclei of the hypothalamus were stated. Direct pathways from the putamen to the subthalamic nucleus have been revealed, however, these pathways are represented in less degree than those of pallido-subthalamic connections. Direct pathways from the external portion of the globus pallidus and putamen to the subthalamic nucleus are more pronounced and represented by greater numbers of projections than those of strio-pallido-hypothalamic origin.  相似文献   

4.

Background

Although expert opinion has asserted that there is an increased risk of violence in individuals with schizophrenia and other psychoses, there is substantial heterogeneity between studies reporting risk of violence, and uncertainty over the causes of this heterogeneity. We undertook a systematic review of studies that report on associations between violence and schizophrenia and other psychoses. In addition, we conducted a systematic review of investigations that reported on risk of homicide in individuals with schizophrenia and other psychoses.

Methods and Findings

Bibliographic databases and reference lists were searched from 1970 to February 2009 for studies that reported on risks of interpersonal violence and/or violent criminality in individuals with schizophrenia and other psychoses compared with general population samples. These data were meta-analysed and odds ratios (ORs) were pooled using random-effects models. Ten demographic and clinical variables were extracted from each study to test for any observed heterogeneity in the risk estimates. We identified 20 individual studies reporting data from 18,423 individuals with schizophrenia and other psychoses. In men, ORs for the comparison of violence in those with schizophrenia and other psychoses with those without mental disorders varied from 1 to 7 with substantial heterogeneity (I 2 = 86%). In women, ORs ranged from 4 to 29 with substantial heterogeneity (I 2 = 85%). The effect of comorbid substance abuse was marked with the random-effects ORs of 2.1 (95% confidence interval [CI] 1.7–2.7) without comorbidity, and an OR of 8.9 (95% CI 5.4–14.7) with comorbidity (p<0.001 on metaregression). Risk estimates of violence in individuals with substance abuse (but without psychosis) were similar to those in individuals with psychosis with substance abuse comorbidity, and higher than all studies with psychosis irrespective of comorbidity. Choice of outcome measure, whether the sample was diagnosed with schizophrenia or with nonschizophrenic psychoses, study location, or study period were not significantly associated with risk estimates on subgroup or metaregression analysis. Further research is necessary to establish whether longitudinal designs were associated with lower risk estimates. The risk for homicide was increased in individuals with psychosis (with and without comorbid substance abuse) compared with general population controls (random-effects OR = 19.5, 95% CI 14.7–25.8).

Conclusions

Schizophrenia and other psychoses are associated with violence and violent offending, particularly homicide. However, most of the excess risk appears to be mediated by substance abuse comorbidity. The risk in these patients with comorbidity is similar to that for substance abuse without psychosis. Public health strategies for violence reduction could consider focusing on the primary and secondary prevention of substance abuse. Please see later in the article for Editors'' Summary  相似文献   

5.
Two molecular forms of prolactin (PRL), glycosylated and non-glycosylated, were isolated from pituitary glands of two reptiles, alligator and crocodile. The reptilian PRLs were extracted under alkaline conditions from the precipitate obtained after pituitaries were first extracted with 0.25 M sucrose, 1 mM NH4HCO3, pH 6.3. Purification was performed by ion exchange chromatography on DE-52, gel filtration on Sephadex G-75 superfine, and reversed phase high performance liquid chromatography. Two forms of both alligator and crocodile PRL, designated PRLI and PRLII, with molecular weights of 26,000 and 24,000 were isolated. Alligator and crocodile PRLI and PRLII were stained specifically in immunoblots with anti-sea turtle PRL and anti-ostrich PRL. Sequence analysis revealed that both forms of alligator and crocodile PRLs consisted of 199 amino acid residues with a glycosylation consensus sequence (Asn-Ala-Ser) at position 60 in alligator and crocodile PRLs with a molecular weight of 26,000 (PRLI). In contrast, Thr was substituted for Asn at position 60 in the PRLs with a molecular weight of 24,000 (PRLII). The sequences of alligator PRLs differed from crocodile PRLs only in position 134: Val for alligator PRLs and Ile for crocodile PRLs. There is a high degree of structural conservation between the reptilian PRLs isolated in this study and avian PRL; each showed 92% sequence identity with chicken PRL and 89% with turkey PRL.  相似文献   

6.
Protein and RNA syntheses were investigated with bulk isolated nerve and glial cells from rabbit brain. For polypeptide synthesis, ‘intact’ cells were incubated with [3H]leucine under various conditions and the results were compared with those of polyribosomal polypeptide synthesis. For RNA synthesis ‘intact’ cells were incubated with [3H]uridine or [3H]guanosine and the results were compared with those of DNA-dependent RNA polymerase assay. The bulk isolated ‘intact’ nerve cells were more active in protein synthesis than the ‘intact’ glial cells, while the latter synthesized RNA more actively than the former, although both polyribosomal polypeptide synthesis and DNA-dependent RNA polymerase activity were higher with the nerve cells, indicating a higher potential for the nerve cells. The observed discrepancy of RNA synthesis was explained by the significantly less active uptake of nucleosides with the nerve cells. Both protein and RNA syntheses with ‘intact’ cells were sensitive to hypoxic or glucose-deficient conditions. While both the nerve and glial cells were sensitive to hypoxia to a similar extent, the nerve cells were more sensitive to glucose deficiency. It was suggested that the bulk isolated nerve and glial cells still retain certain integral cell functions as viable cells, and can be utilized for various physiological and pharmacological investigations provided caution is exercised in their application and in the interpretation of the results.  相似文献   

7.
Toxic metals such as cadmium (Cd2+) pose serious risks to human health. However, even though the importance of Cd2+ as environmental health hazards is now widely appreciated, the specific mechanisms by which it produces its adverse effects have yet to be fully elucidated. Cd2+ is known to enter cells, it binds and interacts with a multitude of molecules, it may indirectly induce oxidative stress and interfere with gene expression and repair of DNA. It also interacts with transport across cell membranes and epithelia and may therefore disturb the cell’s homeostasis and function. Interaction with epithelial transport, especially in the kidney and the liver, may have serious consequences in general health. A lot of research still needs to be done to understand the exact way in which Cd2+ interferes with these transport phenomena. It is not always clear whether Cd2+ has primary or secondary effects on cell membrane transport. In the present review we try to summarize the work that has been done up to now and to critically discuss the relevance of the experimental work in vitro with respect to the in vivo situation.  相似文献   

8.
9.
Murine thioglycollate-elicited peritoneal macrophages were cultured in the presence of a variety of fatty acids added as complexes with bovine serum albumin. All fatty acids tested were taken up readily by the cells and both neutral and phospholipid fractions were enriched with the fatty acid provided in the medium. This generated a range of cells enriched in saturated, monounsaturated or polyunsaturated fatty acids, including n-3 acids of fish oil origin. Saturated fatty acid enrichment enhanced macrophage adhesion to both tissue culture plastic and bacterial plastic compared with enrichment with polyunsaturated fatty acids. Macrophages enriched with the saturated fatty acids myristate or palmitate showed decreases of 28% and 21% respectively in their ability to phagocytose unopsonized zymosan particles. Those enriched with polyunsaturated fatty acids showed 25-55% enhancement of phagocytic capacity. The greatest rate of uptake was with arachidonate-enriched cells. Phagocytic rate was highly correlated with the saturated/unsaturated fatty acid ratio, percentage of polyunsaturated fatty acid and index of unsaturation, except for macrophages enriched with fish-oil-derived fatty acids; they showed lower phagocytic activity than expected on the basis of their degree of unsaturation. These results suggest that membrane fluidity is important in determining macrophage adhesion and phagocytic activity. However, in the case of phagocytosis, this effect may be partially overcome if the cells are enriched with fish-oil-derived fatty acids. Thus it may be possible to modulate the activity of cells of the immune system, and so an immune response, by dietary lipid manipulation.  相似文献   

10.
Serum from humans infected with Schistosoma mansoni, when reacted with a Biomphalaria glabrata soluble hepatopancreas antigen extract (BgSHA) yields 2 lines of precipitation by gel diffusion and 1 by immunoelectrophoresis. The IgG from the serum of a human infected with S. mansoni was coupled to CNBr-activated Sepharose 4B. BgSHA (8.0 mg) was then filtered through the gel and the bound antigens, denoted BgSm, eluted with HCl-glycine, pH 2.6. These bound antigens comprised 2.8% of the total BgSHA. BgSm was then applied to an anti-Fasciola hepatica column as above. The drop through in PBS (38% yield) and containing the BgSm antigens depleted of cross-reactivity with F. hepatica was then tested by the ELISA to evaluate its serodiagnostic potential. These antigens detected a primary S. mansoni infection by 4 wk but were less sensitive than SmSEA in the detection of a primary infection with S. mansoni. However, the BgSm-specific antigens were more specific than SmSEA and showed less cross-reactivity with the serum of mice infected with F. hepatica. At least 16 peptides were seen by silver staining following SDS-PAGE with 5-20% gradient gels. The 2 more prominent bands obtained were estimated to have molecular weights of 62 and 66 kd. Nitrocellulose strips blotted with BgSHA were incubated with the serum of mice infected with S. mansoni for 12 wk and developed 6 bands with molecular weights of 66, 57, 55, 50, 48 and 32 kd.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

11.
Superoxide ions (O2-) oxidized oxyhaemoglobin to methaemoglobin and reduced methaemoglobin to oxyhaemoglobin. The reactions of superoxide and H2O2 with oxyhaemoglobin or methaemoglobin and their inhibition by superoxide dismutase or catalase were used to detect the formation of superoxide or H2O2 on autoxidation of oxyhaemoglobin. The rate of autoxidation was decreased at about 35% in the presence of both enzymes. The copper-catalysed autoxidation of Hb (haemoglobin) was also shown to involve superoxide production. Superoxide was released on autoxidation of three unstable haemoglobins and isolated alpha and beta chains, at rates faster than with Hb A. Reactions of superoxide with Hb Christchurch and Hb Belfast were identical with those with Hb A, and occurred at the same rate. Hb Koln contrasted with the other haemoglobins in that the thiol groups of residue beta-93 as well as the haem groups reacted with superoxide. Haemichrome formation from methaemoglobin occurred very rapidly with Hb Christchurch and Hb Belfast, as well as the isolated chains, compared with Hb A. The process did not involve superoxide production or utilization. The relative importance of autoxidation and superoxide production compared with haemichrome formation in the haemolytic process associated with these abnormal haemoglobins and thalassaemia is considered.  相似文献   

12.
Seven strains of axenic unicellular Chlorophyta and three strains ofaxenic Cyanophyta were selected for their high growth rate and positivecytokinin-like activity in the Cucumber Cotyledon Expansion Bioassay. Ethanolicextracts of these ten strains were purified using cation exchange resin andpaper chromatography and then screened for cytokinin-like activity using theSoybean Callus Bioassay. No trend was detected in the Cyanophyta with onespecies having two peaks of cytokinin-like activity co-eluting with zeatinderivatives and iso-pentenyladenine derivatives and theother two species having only one peak of activity co-eluting with zeatinderivatives. Four Chlorophyta only had one peak of cytokinin-like activity,co-eluting with zeatin derivatives, while two species had two peaks of activityco-eluting with zeatin and iso-pentenyladeninederivatives.One Chlorophyta species had no detectable cytokinin-like activity. The same tenstrains were also tested for auxin-like activity. The water extract of sevenstrains demonstrated auxin-like activity in the Cucumber Cotyledon RootFormation Bioassay. No auxin-like activity was detected in any of the strainsusing the Mung Bean Bioassay after being extracted in methanol and purified byphase partitioning with phosphate buffer and ethyl acetate.  相似文献   

13.
14.
Together with the synthesis of specific antibodies and autoantibodies, effects of cellular allergy, such as damage to neutrophils, agglomeration of leukocytes and inhibition of migration of leukocytes with tuberculin and isologous pulmonary antigen were established in patients with silicosis and silicotuberculosis. Autoallergy becomes manifest already in the "pre-roentgenological" stage of development of silicosis; in silicotuberculosis it correlates with the stage of the specific process. In both silicosis and silicotuberculosis, it includes elements of immediate and delayed hypersensitivity. In clinical practice, allergic reactions of leukocytes with tuberculin can be of assistance in determining the stage of the specific process and in differential diagnosis of silicosis and silicotuberculosis.  相似文献   

15.
N. T. McPhedran  R. D. Henderson 《CMAJ》1965,92(24):1258-1260
The records of 147 patients who had pruritus and jaundice (11% of a series of 1262 patients with jaundice) were reviewed in an effort to delineate more clearly the etiology of jaundice associated with pruritus.Fifty-two had obstructive jaundice caused by neoplasm, 51 had obstructive jaundice not caused by neoplasm, 42 had pruritus associated with hepatogenous jaundice, and two had jaundice and pruritus associated with a lymphoma.Pruritus occurred in 17% of all patients with non-neoplastic obstructive jaundice and in 45% of patients with neoplastic obstructive jaundice. Hepatogenous jaundice was the cause of pruritus in almost one-third of the patients in this series-occurring in 20% of patients with infectious hepatitis and in 7% of patients with cirrhosis.This large series confirms the clinical impression that pruritus occurs most often in association with extrahepatic biliary obstruction, and as well re-emphasizes the common association of pruritus with hepatogenous jaundice.  相似文献   

16.
The essential trace element selenium (Se) is required for thyroid hormone synthesis and metabolism. Selenoproteins contain selenocysteine and are responsible for biological functions of selenium. Glutathione peroxidase (GPx) is one of the major selenoproteins which protects the thyroid cells from oxidative damage. Selenoprotein P (SePP) is considered as the plasma selenium transporter to tissues. The aim of this study was to evaluate serum Se and SePP levels, and GPx activity in erythrocytes of children and adolescents with treated Hashimoto’s thyroiditis, hypothyroidism, and normal subjects.Blood samples were collected from 32 patients with Hashimoto’s thyroiditis, 20 with hypothyroidism, and 25 matched normal subjects. All the patients were under treatment with levothyroxine and at the time of analysis all of the thyroid function tests were normal. GPx enzyme activity was measured by spectrophotometry at 340 nm. Serum selenium levels were measured by high-resolution continuum source graphite furnace atomic absorption. SePP, TPOAb (anti-thyroid peroxidase antibody), and TgAb (anti-thyroglobulin antibody) were determined by ELISA kits. T4, T3, T3 uptake and TSH were also measured.Neither GPx activity nor SePP levels were significantly different in patients with Hashimoto’s thyroiditis or hypothyroidism compared to normal subjects. Although GPx and SePP were both lower in patients with hypothyroidism compared to those with Hashimoto’s thyroiditis and normal subjects but the difference was not significant. Serum Se levels also did not differ significantly in patients and normal subjects. We did not find any correlation between GPx or SePP with TPOAb or TgAb but SePP was significantly correlated with Se.Results show that in patients with Hashimoto’s thyroiditis or hypothyroidism who have been under treatment with levothyroxine and have normal thyroid function tests, the GPx, SePP and Se levels are not significantly different.  相似文献   

17.
The inner muscles of the larynx have been dissected and its length values and circumferences were measured. The potential force of the posterior cricothyroid muscle was estimated with 26,65 N of the arytenoid muscles with 17,24 N, and for the lateral crico-arytenoid and thyreoarytenoid external muscles with 26,56 N. The development and the functions of the muscles are discussed.  相似文献   

18.
The objective of this retrospective cohort study was to determine the effect of tumor necrosis factor inhibitor (TNFi) therapy on the risk of head and neck cancer (HNC) recurrence or HNC-attributable death in patients with rheumatoid arthritis (RA). RA patients with HNC were assembled from the US national Veterans’ Affairs (VA) administrative databases, and diagnoses confirmed and data collected by electronic medical record review. The cohort was divided into those treated with non-biologic disease-modifying anti-rheumatic drugs (nbDMARDs) versus TNF inhibitors (TNFi) after a diagnosis of HNC. Likelihood of a composite endpoint of recurrence or HNC-attributable death was determined by Cox proportional hazards regression. Of 180 patients with RA and HNC, 31 were treated with TNFi and 149 with nbDMARDs after the diagnosis of HNC. Recurrence or HNC-attributable death occurred in 5/31 (16.1%) patients in the TNFi group and 44/149 (29.5%) patients in the nbDMARD group (p = 0.17); it occurred in 2/16 (13%) patients who received TNFi in the year prior to HNC diagnosis but not after. Overall stage at diagnosis (p = 0.03) and stage 4 HNC (HR 2.49 [CI 1.06–5.89]; p = 0.04) were risk factors for recurrence or HNC-attributable death; treatment with radiation or surgery was associated with a lower risk (HR 0.35 [CI 0.17–0.74]; p = 0.01 and HR 0.39 [CI 0.20–0.76]; p = 0.01 respectively). Treatment with TNFi was not a risk factor for recurrence or HNC-attributable death (HR 0.75; CI 0.31–1.85; p = 0.54). We conclude that treatment with TNFi may be safe in patients with RA and HNC, especially as the time interval between HNC treatment and non-recurrence increases. In this study, TNF inhibition was not associated with an increase in recurrence or HNC-attributable death.  相似文献   

19.
Tyrosine phenol-lyase (TPL) and tryptophan indole-lyase (Trpase) catalyse the reversible hydrolytic cleavage of L-tyrosine or L-tryptophan to phenol or indole, respectively, and ammonium pyruvate. These enzymes are very similar in sequence and structure, but show strict specificity for their respective physiological substrates. We have mutated the active site residues of TPL (Thr(124), Arg(381), and Phe(448)) to those of Trpase and evaluated the effects of the mutations. Tyr(71) in Citrobacter freundii TPL, and Tyr(74) in E. coli Trpase, are essential for activity with both substrates. Mutation of Arg(381) of TPL to Ala, Ile, or Val (the corresponding residues in the active site of Trpase) results in a dramatic decrease in L-Tyr beta-elimination activity, with little effect on the activity of other substrates. Arg(381) may be the catalytic base with pK(a) of 8 seen in pH-dependent kinetic studies. T124D TPL has no measureable activity with L-Tyr or 3-F-L-Tyr as substrate, despite having high activity with SOPC. T124A TPL has very low but detectable activity, which is about 500-fold less than wild-type TPL, with L-Tyr and 3-F-L-Tyr. F448H TPL also has very low activity with L-Tyr. None of the mutant TPLs has any detectable activity with L-Trp as substrate. H463F Trpase also exhibits low activity with L-Trp, but retains high activity with other substrates. Thus, additional residues remote from the active site may be needed for substrate specificity. Both Trpase and TPL may react by a rare S(E)2-type mechanism.  相似文献   

20.
The chemical synthesis of 2 alpha, 17 alpha-diethynyl-A-nor-5 alpha-androstane-2 beta, 17 beta-diol dipropionate (Anordrin) and the corresponding diacetate is reported. Similarly, the preparation of the 2 alpha, 17 alpha-diethynyl-A-nor-5 alpha-estrane-2 beta, 17 beta-diol, its diacetate and dipropionate (Dinordrin I), along with the corresponding 2 beta-epimer (Dinordrin II) from 17 beta-hydroxy-A-nor-5 alpha=estran-2-one is described. In rat uterotrophic activity bioassay, the slope of ethynylestradiol differed significantly from the slopes of the other three compounds, thus vitiating potency estimates with this reference compound. Dinordrin I was 20 times more potent than Anordrin and considerably more potent then Dinordrin II. The single-dose oral antifertility effect in rats generally paralleled uterotrophic activity. Immediate postovulatory contraceptive effectiveness was assessed in adult cycling female baboons given two doses daily for 4 days. Both Anordrin and Dinordrin I showed antifertility activity worthy of further study. Moreover, a definite luteolytic effect, with depression of both plasma estrogen and progesterone levels, was observed with these two steroids.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号