Changes in Serum TSH and Free T4 during Human Sleep Restriction

Study Objectives:

To examine whether recurrent sleep restriction is accompanied by changes in measures of thyroid function.

Design:

Two-period crossover intervention study.

Setting:

University clinical research center and sleep laboratory.

Participants:

11 healthy volunteers (5F/6M) with a mean (± SD) age of 39 ± 5 y and BMI 26.5 ± 1.5 kg/m².

Intervention:

Randomized exposure to 14 days of sedentary living with ad libitum food intake and 5.5- vs. 8.5-h overnight sleep opportunity.

Measurements and Results:

Serum thyroid-stimulating hormone (TSH) and free thyroxine (T4) were measured at the end of each intervention. Partial sleep restriction was accompanied by a modest but statistically significant reduction in TSH and free T4, seen mainly in the female participants of the study.

Conclusions:

Compared to the well-known rise in TSH and thyroid hormone concentrations during acute sleep loss, tests obtained after 14 days of partial sleep restriction did not show a similar activation of the human thyroid axis.

Citation:

Kessler L; Nedeltcheva A; Imperial J; Penev PD. Changes in serum TSH and free T4 during human sleep restriction. SLEEP 2010;33(8):1115-1118.     

Apnoea induced by airflow obstruction

Total obstruction of the airways caused all respiratory efforts to stop on 15 occasions in 10 preterm babies. This was not seen in 60 studies on 38 term babies. These findings suggest that failure to achieve an oral airway may not be the only mechanism by which upper airway obstruction might cause the cot death syndrome.     

Ultrasonographic evaluation of knee joint cartilage in rheumatoid arthritis patients

The non-invasive methods used to study joint cartilage are restricted in their scope. No direct visualization of the joint cartilage is possible in conventional radiology and tomography and the decrease in joint space is only indirect evidence for joint destruction. CT is a radiologic method for direct visualization of joint cartilage but its diagnostic precision in the evaluation of early cartilage lesions is limited because it can not produce an image in a plane other than the transversal plane perpendicular to the direction of the main axis of the body and because it has limited spatial resolution. Other methods for direct visualization of joint cartilage are arthrography and arthroscopy which are little used in clinical practice because of their invasiveness and limited indications. MRI is a promising technique but its usage is limited by the high price and limited accessibility. Our object in the present study was to evaluate the significance of arthro-sonography in the diagnosis of early arthritic lesions of knee cartilage, based on the ultrasonographic assessment of the joint surface and cartilage thickness. Femoral cartilage was our choice for the study as there is statistically well documented high incidence of early arthritic changes in this area; moreover, the area is easily accessible for ultrasound evaluation using a scan perpendicular to the articular surface, incl. the cases with complete flexion of the knee joint, where the pressure areas of the condyles are apositioned to the tibial plateau. Using a 7.5 MHz transducer we managed to measure and document early arthritic changes in joint thickness and the contour of the joint surfaces before they can be detected using routine radiologic methods.     

Leptin concentrations in the follicular phase of spontaneous cycles and cycles superovulated with follicle stimulating hormone

It has been reported that oestradiol may play a role in the production of leptin from adipocytes. To investigate this relationship further, nine normally ovulating women were studied during two menstrual cycles, i.e. an untreated spontaneous cycle and a cycle treated with follicle stimulating hormone (FSH) from cycle day 2 until the day of human chorionic gonadotrophin (HCG) injection. Serum leptin values on cycle day 2 did not differ significantly between the spontaneous and the FSH cycles. In the spontaneous cycles, leptin values declined gradually and significantly up to day 7 and then increased progressively up to the day of luteinizing hormone (LH) surge onset, at which point they achieved the highest values. In the FSH cycles, serum leptin values increased gradually and significantly up to day 6, remaining stable thereafter, and were in the midfollicular phase significantly higher than in the spontaneous cycles. Significant positive correlations were found between mean values of leptin and mean values of oestradiol during the second half of the follicular phase in the spontaneous cycles and during the first half in the FSH cycles. A significant negative correlation was found between these two parameters in the spontaneous cycles during the first half of the follicular phase. Serum leptin levels were significantly higher in the midluteal than in the follicular phase in both cycles. These results demonstrate for the first time significant changes in leptin values during the follicular phase of the human menstrual cycle and a significant increase during superovulation induction with FSH. It is suggested that oestradiol may be involved in the regulation of leptin production in women.      

Current and future status of ovulation induction in polycystic ovary syndrome

Great progress has been achieved during the last 20 years inthe field of ovulation induction in patients with polycysticovary syndrome (PCOS). Clomiphene citrate remains the firstline of treatment for all anovulatory women with PCOS, sincein properly selected patients the cumulative pregnancy rateapproaches that in normal women. Human urinary gonadotrophinshave been used extensively for ovulation induction but the developmentof low-dose regimens has opened a new era in the managementof anovulation related to PCOS. This article discusses the mainadvantages and disadvantages of the principal methods and regimenscurrently used for ovulation induction in patients with PCOSincluding clomiphene citrate, gonadotrophins, pulsatile gonadotrophin-releasinghormone (GnRH) and GnRH agonists. It also discusses new drugsdiscovered recently, particularly recombinant gonadotrophinsand GnRH antagonists, and provides some thoughts regarding theiruse in future protocols. Finally, based on the discovery ofnew ovarian substances which specifically control luteinizinghormone (LH) secretion, this article develops assumptions onpossible implications of these substances in the pathophysiologyof PCOS and their potential use in the management of the syndrome.     

实验性高胆固醇血症兔离体主动脉功能变化的研究

目的探讨高胆固醇血症对血管功能的影响。方法20只新西兰雄性兔随机分为2组正常饮食组(normal cholesterol,NC)10只及高胆固醇饮食组(hypercholesterol,HC)10只。4周后取出每只兔的降主动脉,5mm宽动脉环放置于含有25mlKreb液的组织－器官水浴系统中。分别测量游离血管对乙酰胆碱（10-10～10-5mol/L)的舒张反应及对去甲肾上腺素（10-10～10-5mol/L）的收缩反应。结果2组兔血胆固醇有显著差异,其中NC组（30.1±11.2）mg/dl,HC组（987.3±110.0)mg/dl(P<0.01);HC组血管对乙酰胆碱舒张反应与NC组比较明显减弱,HC组最大为（58.50±6.17）％,NC组最大为(103.2±6.9)％(P<0.01）;HC组血管对去甲肾上腺素反应增强,最大收缩力HC组为(4.15±0.56)g,NC组为(2.9±0.3)g(P<0.05）。2组动脉病理学检查无动脉硬化的改变。结论高胆固醇血症降低血管内皮依赖性舒张反应,增加血管对去甲肾上腺素的收缩反应。高胆固醇血症时血管内皮功能改变早于动脉粥样硬化的结构改变。     

2型糖尿病患者血浆同型半胱氨酸水平与冠心病的关系

目的探讨2型糖尿病患者血浆同型半胱氨酸（homocysteine,Hcy）水平与冠心病是否相关。方法回顾性分析169例2型糖尿病并已行选择性冠脉造影的患者,按冠脉狭窄程度分为对照组,单支组,双支组和多支病变组,分析不同组别Hcy及其他临床生化指标。结果冠心病各亚组Hcy均高于对照组（P〈0.05）,Hcy随冠脉病变程度的加重而升高,多支病变组Hcy明显高于单支组,与之呈正相关（P〈0.05）;多元逐步回归分析显示血浆同型半胱氨酸与冠脉狭窄程度明显相关（P〈0.05）。结论2型糖尿病患者血浆同型半胱氨酸水平升高有可能加重冠脉粥样硬化。