[Klinefelter syndrome: Advances in research].

Klinefelter syndrome (KS) is a most common chromosome abnormality and frequently leads to male infertility. In recent years, deeper insights have been gained into the treatment of KS in children, clinical manifestations of KS, as well as reproductive problems and pre- and postnatal screening of the disease. This article presents an overview of the epidemiology, clinical manifestations, pathophysiological mechanism, laboratory examination, drug therapy and application of assisted reproductive technology, and KS screening, aiming to provide some reference for KS-related clinical practice.

The Role of NF mRNA and Calpain in NF Reduction of Acrylamide Neuropathy.

The purpose of this study was to study the role of neurofilament (NF) mRNA and calpain in NF reduction of acrylamide (ACR) neuropathy. Male Wistar adult rats were injected i.p. every other day with ACR (20 mg/kg·bW or 40 mg/kg·bW) for 8 weeks. NF mRNA expression was detected using RT-PCR and the calpain concentration was determined using western blot analysis. The NF mRNA expression significantly decreased while the level of m-calpain and µ-calpain significantly increased in two ACR-treated rats groups regardless of the ACR dose. The light NF (NF-L) protein expression was significantly correlated with NF-L mRNA expression. Combined with previous data, the concentrations of three NF subunits were negatively correlated with the calpain levels. These findings suggest that NF-L mRNA and calpain mediated the reduction in NF of ACR neuropathy.

[Structural equation model analysis of risk factors for low back pain among greenhouse vegetable-planting farmers].

OBJECTIVE: To explore the risk factors of low back pain (LBP) among greenhouse vegetable planting farmers and estimate the level of the effects. METHODS: A self-made questionnaire based on the Dutch Musculoskeletal Questionnaire and the Nordic Questionnaire was conducted to 639 greenhouse vegetable planting farmers and then structural equation model was used to analyze the risk factors of LBP in SmartPLS software. RESULTS: The coefficient of determination of the model was 0.827, and the structural coefficients of dynamic loads, static loads, force exertion, ergonomic environment and repetitive loads on LBP were 0.21, 0.43,0.27, 0.045 and 0.034 respectively, and the total effects of the above latent variables on LBP were 0.21, 0.43,0.27, 0.33 and 0.034 respectively. CONCLUSION: The main risk factors of LBP among greenhouse vegetable planting farmers were static loads, ergonomic environment, force exertion and dynamic loads.

[Expression changes of cyclin dependent kinase 5/p35 in nerve tissues of 2, 5-hexanedione intoxicated rats].

OBJECTIVE: To explore the role of cyclin dependent kinase 5 (CDK5) in 2, 5-hexanedione (HD)-induced neuropathy. METHODS: Thirty male Wistar rats weighted 200 approximately 240 g were divided randomly into three groups, i.e. control group, 200 mg/kg HD group and 400 mg/kg HD group (n = 10 for each group). HD was administered to rats by intraperitoneal injection at dosage of 200 or 400 mg/kg for 8 weeks (five times per week) to establish the intoxicated rats model. The relative contents of CDK5, p35 and p25 were determined in cerebrum, spinal cord and sciatic nerve of rats by Western Blotting. RESULTS: Compared with that of the control group rats, p35 contents were significantly decreased (P < 0.01) in the cytosolic fractions of cerebrum and spinal cord in both the 200 and 400 mg/kg HD intoxicated rats, while in the membrane fractions of spinal cord and sciatic nerve, p35 contents were increased significantly (P < 0.01). The changes of p25 showed the same pattern with p35. P25 contents were significantly reduced (P < 0.05) in the cytosolic (cerebrum and spinal cord) and membrane (cerebrum) fractions of both HD-treated rats and were elevated (P < 0.01) in the membrane fraction of spinal cord and cytosolic fraction of sciatic nerve. The relative amounts of CDK5 were significantly decreased (P < 0.01) in the cytosolic and membrane fractions of cerebrum in both the 200 and 400 mg/kg HD intoxicated rats. Except for membrane fraction of sciatic nerve, the significant increased (P < 0.01) of CDK5 were observed in the spinal cord and sciatic nerve of both the 200 and 400 mg/kg HD treated rats. CONCLUSION: HD can induce significant changes of CDK5 and its activators p35, p25 in nerve tissues, which may be related to the neuropathy induced by HD.

Involvement of cyclin-dependent kinase 5 in 2,5-hexanedione-induced neuropathy.

Occupational exposure to n-hexane produces a neuropathy characterized as a central-peripheral distal axonopathy, which is mediated by 2,5-hexanedione (HD). To investigate the mechanisms of the neuropathy induced by HD, the contents and activities of cyclin-dependent kinase 5 (CDK5) and activators (p35 precursor, p35 and p25) in rats' cerebrum cortex (CC), spinal cord (SC) and sciatic nerve (SN) were determined. The results showed that the levels and activities of CDK5 in CC of 200 or 400mg/kg HD-treated rats were significantly decreased in both the cytosolic and membrane fractions and negatively correlated with gait abnormality in the cytosolic fraction. However, CDK5 contents and activities in SN of rats treated with 200 or 400mg/kg HD were significantly increased and positively correlated with gait abnormality in both the cytosolic and membrane fractions. Although increases of CDK5 contents in both the cytosolic and membrane fractions of SC in 200 and 400mg/kg HD-treated rats were also observed, CDK5 activities were significantly decreased in the cytosolic fraction and negatively correlated with gait abnormality. The changes of p35 precursor, p35 and p25 contents in CC, SC and SN showed the same pattern with that of CDK5 activities. Thus, HD intoxication was associated with deregulation of CDK5 and its activator p35 or p25 in nerve tissues. The inconsistent changes of CDK5 activities in CNS and PNS might delegate the different mechanisms of HD-induced peripheral neuropathy.