Impact level of dihydrotestosterone on the hypothalamic-pituitary-leydig cell axis in men

Dihydrotestosterone (DHT) the physiologically most potent androgen cannot be aromatised into oestrogen. DHT is used as a treatment for idiopathic gynaecomastia. In order to investigate the different sites of action of DHT on the hypothalamic-pituitary-testicular axis, two groups of adult men were studied. Group I included 10 gonadotropin-releasing hormone (GnRH)-deficient men who were evaluated before and during a pulsatile infusion of GnRH alone for 2 weeks and then in association with DHT given transdermally at doses used in the treatment of gynaecomastia for further two weeks. Luteinizing hormone (LH) pulsatility was assessed at the end of each step of the study. Plasma LH levels were measured every 15 min. Plasma testosterone (T), DHT, oestradiol (E2), free alpha-subunit (FAS) of glycoproteic hormones and LH bioactivity were measured on pooled plasma samples. Group II included 12 healthy men in whom plasma T, DHT and E2 were measured before and then 24, 48 and 72 h after the injection of 5000 IU hCG alone or in combination with either DHT or the pure anti-androgen nilutamide. Two weeks separated each of the 3 hCG testing. In group I, except for bioactive/immunoreactive (B/I) LH ratio which was unchanged, GnRH treatment induced significant rises (p < 0.01) in all plasma hormone levels, LH pulse amplitude and frequency. During treatment with GnRH+DHT, plasma DHT levels increased up to 16.8 +/- 2.5 nm, while plasma hormone levels, B/I LH ratio, LH pulse amplitude and frequency were similar to those obtained with GnRH alone. In group II, the peak of hCG-induced T rise was not modified by either DHT or nilutamide. In contrast, DHT reduced by 50% (p < 0.01) the E2 peak in response to hCG. These data show that DHT exerts no direct action on the pituitary to retroregulate LH secretion and to modify either B/I LH ratio or FAS secretion. Its reducing effect on LH secretion is likely mediated at the hypothalamic level. DHT does not appear to have a physiological influence on Leydig cells steroidogenesis. Administered at therapeutic doses, DHT directly reduces testicular aromatase activity that combined with its antigonadotropic effect leads to the gain in the symptomatic treatment of gynaecomastia.     

垂体腺苷酸环化酶激活多肽调节LPS激活的树突状细胞免疫功能

目的:研究垂体腺苷酸环化酶激活多肽(pituitary adenylate cyclase-activating polypeptide,PACAP)能否调节小鼠骨髓起源的LPS激活的树突状细胞(dendritic cell,DC)的免疫功能。方法:联合应用rmGM-CSF和rmIL-4自C57BL/6小鼠骨髓细胞制备DC,以LPS和(或)PACAP刺激DC;收集被激活的DC及其上清液行ELISA和流式细胞术分析;自DC提取总RNA行RT-PCR和RNase分析。结果:PACAP能明显抑制LPS激活的DC分泌细胞因子IL-2、IL-12和TNF-α(P<0.05,P<0.01,P<0.01),以及LPS激活的DC分泌趋化因子MIP-2(P<0.01),但抑制细胞因子IL-6,趋化因子MIP-1α和MIP-1β的作用并不明显(P>0.05)。结论:PACAP对LPS激活的DC的免疫功能具有负性调节作用。     

Chromium VI administration induces oxidative stress in hypothalamus and anterior pituitary gland from male rats

Hexavalent chromium (Cr VI)-containing compounds are known carcinogens which are present in industrial settings and in the environment. The major route of chromium exposure for the general population is oral intake. Previously we have observed that Cr VI affects anterior pituitary secretion and causes oxidative stress in vitro. The aim of the present work was to investigate if in vivo Cr VI treatment (100 ppm of Cr VI in drinking water for up 30 days) causes oxidative stress in hypothalamus and anterior pituitary gland from male rats. This treatment produced a 4-fold increase of chromium content in hypothalamus and 10-fold increase in anterior pituitary gland. Lipid peroxidation showed a significant increase in hypothalamus and anterior pituitary. Cr VI augmented superoxide dismutase activity in anterior pituitary gland and glutathione reductase activity in hypothalamus, but glutathione peroxidase and catalase activities remained unchanged in both tissues. Heme oxygenase-1 mRNA expression significantly rose in both tissues. Metallothionein 1 mRNA content increased in anterior pituitary and metallothionein 3 mRNA increased in hypothalamus. These results show, for the first time, that oral chronic administration of Cr VI produces oxidative stress on the hypothalamus and anterior pituitary gland which may affect normal endocrine function.     

Complications of transsphenoidal surgery for sellar region: intracranial vessel injury

Background Intracranial vessel injury is a severe complication of transsphenoidal surgery （TSS） for lesions of sellar region. The purpose of this study was to improve recognition of the complication.
Methods The clinical data of 400 cases of TSS for sellar region from 1964 to 2004 were reviewed retrospectively. Ten patients with complications of intracranial vessel injury were included in this study, 7 underwent transsphenoidal microsurgery and 3 underwent endoscopic TSS. Subarachnoid hemorrhage （SAH） occurred in 8 cases, hemorrhage of cavernous sinus in one, and post-operative cerebral hemorrhagic infarction caused by thrombosis of injured right internal carotid artery in one. The clinical data of all the patients were analyzed.
Results The SAH resulted from hemorrhage of residues of tumor in 2 patients and from damaged sellar and arachnoidea in 6 patients. The cause of hemorrhage of anterior intercavernous sinus was malformation of anterior intercavernous sinus. The reason of thrombus of internal carotid artery was manipulation of operation. Three patients died and six patients were cured. One patient lived with hemiplegia.
Conclusions The cause of intracranial vessels injury of TSS is complicated. Detailed anatomic knowledge of seller and skilled operation is helpful to reduce the complication.     

垂体脓肿的MRI诊断及鉴别诊断

目的探讨垂体脓肿的MRI诊断与鉴别诊断和临床特点。方法回顾性分析6例经手术病理证实的垂体脓肿的MRI表现,所有患者术前均行MR平扫和增强。结果6例均表现为垂体腺增大,向鞍上突出;5例MR平扫T1WI呈低信号,1例呈等信号;4例T2WI呈脑脊液样高信号,2例呈稍高信号;MR增强扫描均呈环形强化,且环壁薄而均匀,部分环壁稍厚。结论平扫T1WI呈低或等信号、T2WI呈脑脊液样高信号或稍高信号及增强呈环形强化是垂体脓肿的主要MR表现。     

Objective assessment of the severity of unilateral facial palsy using OKAO Vision® facial image analysis software

Vestibular compensation is defined as the process of behavioural recovery that occurs following the loss of sensory input from one or both vestibular labyrinths. The visual and postural instability resulting from the vestibular damage must alter the homeostasis of the subject; however, very little research has been conducted that investigates the interaction between vestibular compensation and the adaptive stress response of the body, i.e. the hypothalamic—pituitary—adrenal (HPA) axis. The aim of this review is to describe and evaluate the experimental evidence indicating a link between vestibular compensation and the body's response to stress, via the HPA axis.