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 15 毫秒
1.
2.
Myelinated cultures of mouse spinal cord were exposed to sera obtained from rabbits affected by experimental allergic encephalomyelitis following challenge with whole white matter in complete Freund's adjuvant. In the presence of complement, the tissue response begins with an increased birefringence of its myelin sheaths. This is rapidly followed by a gamut of changes leading to demyelination. This study reports that, in the absence of complement, the response is arrested at the stage of increased birefringence. In this way, this early stage of the demyelinating process was available for detailed examination by light and electron microscopy. The brightened myelin sheaths appeared with a few hours of exposure and were seen around all axons and sometimes around cell bodies. This was often accompanied by abrupt breaks in the sheaths and angularly shaped myelin figures. Examination by electron microscope revealed a uniform increase in the myelin period from 11 nm. to 22 nm. The normally double intraperiod line was increased to four electron-dense leaflets, the additional two appearing to be derived from the close apposition of an additional electron-dense layer on the outer surface of the myelin sheath or oligodendrocytic membrane. Oligondendrocytes responsed with a prolific growth of processes whose membranes compacted to form swollen myelin. Neurons, astrocytes, and neuropil showed no changes. In its early stages, at least, the swelling was reversible. It would appear, therefore, that we have isolated the first stage of antiserum-induced demyelination in vitro, a stage which is now available for further study.  相似文献   

3.
The first successful analysis of estrogens in serum and urine was performed by mass fragmentography using a GC-MS combined system. The equipment used was Shimadzu LKB 9000 GC-MS (MID-PM). The TMSi derivative of the compounds were analyzed using the GC-MS system equipped with a 3 ft x 3mm column packed with 1.5% OV-1 and the temperature was programed from 200 degrees to 260 degrees C at 10 degrees C/min increments. The mass spectrum showed molecular ions at m/e 342, 416 and 504 which correspond to the TMSi derivatives of Estrone (E-1), Estradiol (E-2) and Estriol (E-3) respectively. Molecular ion peak of each compound was applied to establish the precise quantitative evaluation of E-1, E-2 and E-3. 1) The minimum detectable limits of the compounds injected into the column were ca. 2 pg for E-1, E-2 and 5 pg for E-3 respectively. 2) The sensitivity was of the order of ng or pg which enables quantitation with 2 ml of human serum and urine samples obtained from normally ovulating women. 3) This method was very convenient for extracting the compounds from biological fluids, and the procedure can be carried out easily in a short time. 4) Mass fragmentography makes possible the simultaneous measurements of E-1, E-2 and E-3 in samples obtained from pregnant women.  相似文献   

4.
In this review article, the case in favour of the need for psychosexual counselling in family planning practice will be presented. Since psychosexual counselling is a multidisciplinary subject, family planning clinics and practices are ideally suited to the task. In presenting the case, liberal illustrative examples are provided in order to depict what the current and suggested extended facilities and techniques involve. The article is also intended to act as a comprehensive guide for students, nurses, medical practitioners and specialists alike, to bring them up to date in new concepts in history taking, physical examination and the sexually explicit aspects of family planning. Traditionally taught concepts may well be out of date in a modern society.  相似文献   

5.
A chemical method was used for the study of the concentration of the three main groups of oestrogens in the blood of five ewes after mating in natural heat. The concentration values of all the three groups of oestrogens was found to increase in proportion with the length of gravidity. From the 30th to the 140th day of gravidity the average concentration values of oestrone increased from 309 to 1380 ng per 100 ml blood, those of oestradiol from 48 to 192 ng per 100 ml blood. Significant changes were recorded in oestrone between the 50th and 60th day and between the 130th and 140th day of gravidity; in oestradiol and oestriol such changes occurred on the 140th day of gravidity.  相似文献   

6.
This report concerns the evaluation of various estrogens, estrone (El), estradiol (E2), and estrone sulfate (E1S), as well as E1S-sulfatase and aromatase activities in pre- and postmenopausal women with breast cancer. The levels (in picomoles per g; mean +/- SEM) of the various estrogens in the breast tissue from premenopausal patients (n = 11) are: El, 1.4 +/- 0.5; E2, 1.2 +/- 0.6; and E1S, 1.2 +/- 0.3. In postmenopausal patients (n = 23), the values are, respectively, 1.0 +/- 0.4, 1.4 +/- 0.7, and 3.3 +/- 1.9. These concentrations of estrogens in the tumors of postmenopausal patients are significantly higher than those found in plasma. The activity of E1S-sulfatase in both pre- and postmenopausal patients was 50-200 times higher than that of aromatase. E1S-sulfatase and aromatase activities are significantly higher in post-menopausal than in cycling patients. It is concluded that despite the low levels of circulating estrogens in postmenopausal patients, the tissue concentrations of these steroids are several-fold higher than those in plasma, suggesting tumor accumulation of these estrogens. The physiopathology and clinical significance of these high levels of the various estrogens (E1, E2, and E1S) as well as sulfatase and aromatase activities in postmenopausal patients with breast cancer is yet to be explored.  相似文献   

7.
Horse (Equus caballus) luteinizing hormone (eLH) and chorionic gonadotrophin (eCG), which have the same amino acid sequence, are unusual in that, although they express only LH activity in equids, they express dual LH and FSH activities in all other species tested. Donkey (Equus asinus) LH (dkLH) and CG (dkCG), which also share an identical peptide backbone, have been less well characterized and conflicting results concerning their FSH activity in heterologous species have appeared in the literature. In order to assess and compare the intrinsic LH and FSH activities of the horse and donkey LHs in heterologous species, recombinant eLH (r.eLH/CG) and recombinant dkLH (r.dkLH/CG) were expressed, for the first time, in COS-7 cells. Their LH activities were assessed in a rat Leydig cell bioassay, and their FSH activities were estimated in a bioassay using Y1 cells stably expressing the human FSH receptor. Human CG (hCG) was expressed (r.hCG) and analysed in the same system. The results showed that, whereas r.dkLH/CG was about twice as active as r.eLH/CG in the LH bioassay, it was five times less active than r.eLH/CG in the FSH bioassay; r.hCG was about three times less active than r.eLH/CG in the LH bioassay but was completely inactive in the FSH bioassay. These results confirm that dkLH/CG possesses significant FSH activity in heterologous species that is not attributable to contamination with FSH.  相似文献   

8.
9.
Plasma unconjugated estrone (E1), estradiol-17beta (E2) and estriol (E3), and HCS were measured in the same plasma samples collected throughout pregnancy in 19 gestational diabetics (GD) and 21 diabetics (D). When compared to the results obtained in 22 normal subjects, plasma levels of E1 and E2 were significantly elevated in D in the second half of gestation. The results were intermediate although closer to the normals, in GD. E3 values were not different from the normals in both D and GD. HCS values were lower than normal in early pregnancy in both D and GD. In late pregnancy HCS levels were not different from normal in either D or GD, although some individual values were much above the upper limit in some diabetic patients. The hormonal ratios in D and GD parallel those in normals, although E3/E2 and HCS/E2 were lower in D. These results are discussed with respect to the different behaviour of E2 and E3, taking into account the difference in their respective biosynthetic pathways. Besides a possible quantitative modification of the placental function in D, the results could tentatively be explained by a qualitative change in the fetal estrogen precursors to placental aromatization, in favour of the 16 non-hydroxylated compound. However, maternal modifications in precursor production or in estrogen metabolism can be an alternative hypothesis. Finally, the present work does not support the hypothetical estrogen deficiency in diabetic pregnancy. Estrogen treatment appears to have no objective justification.  相似文献   

10.
It had been found previously that exposure of human lymphocytes in vitro to diethylstilbestrol (DES), a synthetic estrogen and known human carcinogen, led to the induction of sister chromatid exchanges. More sister chromatid exchanges were induced in cells from pregnant women than from men. To see if the effects of DES could be induced by other estrogens, lymphocytes from a man and a pregnant woman were treated in vitro with the natural estrogens estradiol and estriol. These did not induce sister chromatid exchanges. To see if the presence of exogenous female hormones might be responsible for the increase in DES-induced sister chromatid exchanges seen in cells from pregnant women, lymphocytes from a man and a pregnant woman were also treated in vitro simultaneously with DES, estradiol, estriol, and progesterone. Treatments with these exogenous hormones did not alter the number of DES-induced sister chromatid exchanges. Our previous studies showed that DES also inhibits in vitro proliferation of lymphocytes. The results reported here show that estradiol also strongly inhibits this proliferation but that estriol is only a weak inhibitor. The cause of delayed cell proliferation induced by DES and estradiol was 2-fold: some of the cells were delayed in phytohemagglutinin-mediated blast cell transformation but, additionally, most cells had a prolonged cell cycle because of an extended G2 phase. These studies also showed that DES, but not estradiol or estriol, induced a low level of polyploidy in human lymphocytes.  相似文献   

11.
The analytical, intra-individual and inter-individual variations as well as the best storage conditions were determined for erythrocyte glutathione, and the reference values were established. A total of 396 apparently healthy people, 206 male, and 190 female, were randomly selected from villages and cities of the southern part of Turkey. The distribution was Gaussian and no significant difference was observed between the male and the female subjects. The mean (standard deviation) of the population investigated for glutathione was 6.9 (1.0) mumol/gHb. The analytical, intra-individual and inter-individual variations were assessed in 20 apparently healthy subjects and were found to be 4.63%, 13.67% and 11.16%, respectively. Whole blood stored at -70 degrees C for up to 10 days was shown to be the best storage condition for erythrocyte glutathione determination. The results of the index of individuality showed that glutathione reference values could be used for diagnostic purposes.  相似文献   

12.
13.
Administration of progesterone eugonadal women during the midfollicular phase of the menstrual cycle failed to induce a positive feedback effect on the serum concentrations of LH and FSH. The levels of estradiol in serum decreased following the injection of progesterone without a parallel change in LH and FSH concentrations indicating a direct ovarian effect of the exogenous progesterone. In the late follicular phase of the cycle, when preovulatory levels of estradiol were present in serum, or under a ethinyl estradiol treatment progesterone was able to induce an LH discharge indicating the requirement of an estradiol priming of the positive feedback of progesterone in eugonadal women. In order to establish the time required for a sufficient estrogen priming with preovulatory levels of estradiol in serum 3 mg of estradiol-benzoate were administered i.m. 1, 12 and 24 h prior to the administration of 30 mg of microcristalline progesterone in the midfollicular phase of the menstrual cycle, when progesterone alone did not cause an LH surge. Only when estradiol-benzoate was injected 24 h prior to the progesterone administration an LH surge reproducible in time course and magnitude occurred. Administration of estradiol-benzoate alone under these conditions did not cause an LH surge within the elapse of time after the injection when the progesterone induced LH surge occurred. Thus, these experiments demonstrate that a defined estrogen priming is required for the positive feedback effect of progesterone on the gonadotropin release in eugonadal women. Furthermore, progesterone levels in serum of about only 1--2 ng/ml were required for the induction of an LH surge indicating that under physiological conditions progesterone may have an supplementory effect on the primarily estradiol induced LH midcycle peak. 17-hydroxyprogesterone administered during the mid follicular phase of the menstrual cycle and under pretreatment with ethinyl estradiol failed to induce a positive feedback effect on the serum concentrations of LH and FSH, indicating that this steroid does not play a regulatory role on the midcycle LH release in women. 20alpha-dihydroprogesterone administered under the same experimental conditions as 17-hydroxyprogesterone seems to be able to induce an LH surge in serum provided there is an adequate estrogen priming.  相似文献   

14.
15.
Pigmentation is a well recognised adverse effect of minocycline therapy. Various body sites, most notably the skin, nails, bones, thyroid, mouth and eyes are affected and the pigmentation may appear at multiple sites. In general, pigmentation results from long term administration of minocycline at cumulative doses greater than 100 g, although cutaneous or oral mucosal pigmentation may appear, regardless of dose or duration of therapy. When the skin is involved, the blue-black pigmentation develops most frequently on the shins, ankles and arms. Other patterns of skin involvement include pigmentation that is either generalised and symmetrical, or that develops at sites of inflammation. The bones of the oral cavity are probably the most frequently affected sites of pigmentation affecting greater than 20% of patients taking minocycline for more than 4 years. In contrast, the oral mucous membranes and teeth are infrequently pigmented from minocycline. Ocular, thyroid and visceral pigmentation is also relatively uncommon and usually develops only with high doses and long term minocycline use. Whereas pigmentation of the skin and oral mucosa is generally reversible when the drug is discontinued, the pigmentation is often permanent when other sites are involved. Although minocycline-induced pigmentation is not harmful, the drug should be discontinued when the adverse effect is recognised. All patients receiving minocycline, especially those treated for longer than 1 year, require screening for the development of pigmentation.  相似文献   

16.
Tachykinins are present in the anterior pituitary gland and there is evidence that they may have a direct intrapituitary role influencing the secretion of some of the hormones released by this gland. In this investigation, we have studied the effect of the non-peptide NK-2 receptor antagonist SR 48,968 (Sanofi Recherche) on the basal release of LH, FSH, and prolactin by rat hemipituitaries incubated in vitro, and also on the response to GnRH. SR 48,968 significantly inhibited prolactin release into the medium. The highest doses of this compound stimulated the basal release of LH by hemipituitaries from castrated, castrated testosterone-treated, and ovariectomized estradiol-treated rats, but not from intact male rats. SR 48,968 significantly inhibited the release of LH in response to GnRH. Since some tachykinin receptor antagonists have been demonstrated to act also on calcium channels, studies with verapamil, a calcium channel antagonist, were also carried out for comparison. Verapamil inhibited prolactin release into the medium and decreased the LH response to GnRH. These results suggest that tachykinins that bind NK-2 receptors, may have an intrapituitary role stimulating the release of prolactin, and that they may also modulate the response of the gonadotrophs to GnRH. The fact that verapamil shares some of the actions exerted by NK-2 receptor antagonists on the pituitary glandm however, suggests the possibility that some of the effects of NK-2 receptor antagonists may be mediated through calcium channel antagonism. Therefore, the results observed with the use of some of these antagonists should be interpreted with great caution.  相似文献   

17.
18.
To assess whether vomitoxin-induced dysregulation of IgA production and IgA nephropathy are reversible, relevant immunologic parameters were compared among experimental groups of B6C3F1 mice that were fed: (1) 25 ppm vomitoxin in AIN-76A semipurified diet for 24 weeks (treatment group), (2) 25 ppm vomitoxin for 8 weeks and then control diet for 16 weeks (withdrawal group), and (3) control diet for 24 weeks (control group). Levels of serum IgA and microhematuria index in the treatment group were elevated after 4 to 8 weeks and continued to increase with further vomitoxin exposure. IgA immune complexes and mesangial IgA deposition, as quantitated by interactive laser cytometer image analysis, were also increased with toxin exposure at Weeks 8, 16, and 24, whereas IgM, IgG, and complement component C3 deposition were unaffected or depressed. Serum IgA, microhematuria index, and mesangial IgA deposition in withdrawal mice remained elevated over those of the controls at Weeks 16 and 24 but were less than those of the treatment group. Cell recovery from Peyer's patches (PP) as well as the percentages of IgA+ and CD4+ cells in PP and spleen at Weeks 16 and 24 were greater in treatment mice than in controls, but only the percentage of IgA+ cells in PP was elevated in the withdrawal mice at these the same time points. When IgA secretion by unstimulated and LPS-stimulated splenic lymphocytes was used as the measure of systemic production, it was elevated in both treatment and withdrawal mice at Weeks 16 and 24. The results indicated that experimental dysregulation of IgA production and IgA nephropathy persisted up to 4 months after a discrete period of dietary vomitoxin exposure, but that the severity of these effects did not increase in a progressive fashion.  相似文献   

19.
Metoclopramide, 4-amino-5-chloro-2-methoxy-N-(2-diethyl-aminoethyl) benzamide, is advocated for use in gastro-intestinal diagnostics, and in treating various types of vomiting and a variety of functional and organic gastro-intestinal disorders. Published data have indicated that metoclopramide assists radiological identification of lesions in the small intestine, facilitates duodenal intubation and small intestine biopsy, and eases emergency endoscopy in upper gastro-intestinal haemorrhage. Metoclopramide reduces post-operative vomiting and radiation sickness, and ameliorates some types of drug-induced vomiting. It may provide symptomatic relief in dyspepsia and possibly in vertigo, reflux oesophagitis and hiccups, but further controlled trials are needed to confirm the efficacy of metoclopramide in these proposed areas of use. It promotes gastric emptying prior to anaesthesia. Its effects in healing gastric ulcer and preventing relapse of duodenal ulcer remain unproven. Side-effects are few and transient, though alarming extrapyramidal reactions can occur in a small proportion of patients receiving therapeutic doses but more usually following excessive doses in young subjects. They respond rapidly to withdrawal of the drug.  相似文献   

20.
The effects on LH release of infusing luteinizing hormone-releasing hormone (LHRH 80 mug/20 min) into the third ventricle, the pituitary, and the peripheral circulation were compared in spayed rhesus monkeys. Within 30 min after iv administration, serum LH concentrations increased to twice to preinfusion levels, and by 120 min declined to original values. Intraventricular or intrapituitary infusions of LHRH resulted in similar LH increments, but the peaks occurred somewhat later (70 to 90 min) and the elevations persisted beyond 200 min. Estradiol-17beta (E2) administered by a sc silastic capsule caused a 5-fold increase in serum E2 within 1 h and reduced serum LH levels by 65% within 4 h. The LH release caused by intrapituitary LHRH was significantly suppressed by maintaining for 72 h E2 concentrations near 100 pg/ml, a level inadequate for stimulating an LH surge. A comparable E2 treatment before intraventricular infusion of LHRH, however, did not inhibit LH release. This difference between the effects of intrapituitary and intraventricular LHRH was demonstrable only in E2-treated monkeys. Moreover, the release of LH after intraventricular infusion of LHRH in E2-treated females was blocked (P less than 0.001) by a single iv injection (90 min before LHRH) of haloperidol (1 mg/kg BW) or phentolamine (5 mg/kg), but was not altered by phenoxybenzamine (3 mg/kg) or propranolol (5 mg/kg). Without E2 pretreatment, LH release after intraventricular LHRH was enhanced by each drug. Phentolamine, injected into both E2- and non-E2-treated monkeys 90 min before an intrapituitary infusion of LHRH had no demonstrable effects on the patterns of serum LH. Our interpretation of these data is that E2 at a concentration below the level that triggers an LH surge has a dual action on LHRH-induced LH release in monkeys: an inhibitory effect exerted directly on the pituitary and a stimulatory effect on the brain. Furthermore, the paradoxical effects of the drugs with and without E2 are due to the involvement of two distinct neuronal systems. The postulated neural effects of both E2 and these drugs can be explained either by an increase in the quantity of injected or secreted LHRH which ultimately binds to LH-secreting cells or by the release of additional endogenous LH-stimulating agents together with ventricular LHRH.  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