The mouse as a model for the study of penile erection: moving towards a smaller animal

We evaluated erectile haemodynamics in mice and characterized the corpus cavernosum morphologically. Four-month-old male BALB/c mice and Sprague-Dawley rats were used. The following stimulation parameters were tested to achieve maximal erectile responses: voltage, 1-6 V; frequency, 6-24 Hz; pulse width, 1 msec; duration, 1 min (n = 7 per group). In a separate group of mice and rats (n = 10 per group), we measured systemic arterial pressure by use of either a 24-gauge angiocatheter or smaller calibre PE-10 tubing. Cavernous tissues from mice, rats or patients with psychogenic erectile dysfunction were stained for factor VIII, alpha-actin and Masson trichrome. Electrical stimulation of the cavernous nerve in mice produced voltage-dependent erectile responses of up to 5 V, with the highest response at a frequency of 12 Hz. The maximal intracavernous pressure recorded at this stimulation parameter was comparable with that in rats. A PE-10 catheter was more reliable for measuring systemic arterial pressure in mice than was a 24-gauge angiocatheter, and the values recorded were similar between mice and rats. The content of endothelial cells, smooth muscle cells and collagen was similar between mice and rats. However, the cavernous tissue of both animals contained lesser amounts of smooth muscle cells and greater amounts of collagen than that of humans (p < 0.01). These results suggest that the mouse is a useful and technically feasible model for the study of penile erection and has functional and structural properties similar to those of rats.     

Prognostic impact of HER-2/neu expression on squamous head and neck carcinomas

BACKGROUND: HER-2/neu gene amplification and protein overexpression have been identified in various solid tumors, but its prognostic relevance in head and neck squamous cell carcinoma (HNSCC) is still controversial. METHODS: The study investigated the expression of HER-2/neu oncoprotein in HNSCC and sought possible correlations to various clinicopathologic parameters. Expression of HER-2/neu oncoprotein was assessed in archival tumor tissues from 87 untreated HNSCC patients by immunohistochemical technique. Data were correlated with both the clinicopathologic parameters and patient survival. RESULTS: A high membranous HER-2/neu protein expression level was found in 39% of patients. Multivariate analysis indicated that HER-2/neu protein expression and pN lymph-node status were independent prognostic factors for disease-free survival. CONCLUSIONS: HER2/neu overexpression and its relationship with survival suggest that new therapeutic approaches targeting epidermal growth factor receptor (EGFR) family receptors could provide a new way of treating HNSCC patients with HER2/neu-positive neoplastic lesions.     

枯草杆菌Bacillus sp F26产过氧化氢酶的发酵条件

从内蒙古呼伦贝尔草原的盐碱湖中分离到的一株低度嗜盐嗜碱细菌Bacillus sp F26，能积累高水平过氧化氢酶（CAT）。对Bacillus sp F26发酵产过氧化氢酶的环境与营养条件的研究结果表明，其积累高水平过氧化氢酶的适宜环境条件为：温度37℃，种龄20-22h，接种量5％，装液量50mL／（250mL的摇瓶）。适宜发酵培养基组成（g／L）为：葡萄糖15，牛肉膏10，玉米浆10，酵母膏5，磷酸二氢钾1，氯化镁0．2，氯化钠50，碳酸钠10。采用上述条件进行摇瓶分批发酵实验，发酵20h，过氧化氢酶酶活达到16．32U／mL，细胞干重为4．12g／L。进一步研究发现，在对数生长后期（16h）添加2mmol／L的H2O2可以明显刺激产酶，在5L的发酵罐上进一步以指数速率方式流加H2O2，由于该流加方式可降低H2O2对细胞的毒害作用，过氧化氢酶酶活达到29．89U／mL，与分批发酵相比提高了92．8％。     

An optimal regulator for linear systems with multiple state and input delays

This paper presents an optimal regulator for a linear system with multiple state and input delays and a quadratic criterion. The optimal regulator equations are obtained reducing the original problem to the linear‐quadratic regulator design for a system without delays. Performance of the obtained optimal regulator is verified in the illustrative example against the best linear regulators available for the linear system without delays and for two rational approximations of the original time‐delay system. Simulation graphs demonstrating better performance of the obtained optimal regulator with respect to the criterion value are included. Copyright © 2006 John Wiley & Sons, Ltd.     

Parametric uncertainty and disturbance attenuation in the suboptimal control of a non‐linear electrochemical process

The optimal control of the hydrogen evolution reactions is attempted for the regulation and change of set‐point problems, taking into account that model parameters are uncertain and I/O signals are corrupted by noise. Bilinear approximations are constructed, and their dimension eventually increased to meet accuracy requirements with respect to the trajectories of the original plant. The current approximate model is used to evaluate the optimal feedback through integration of the Hamiltonian equations. The initial value for the costate is found by solving a state‐dependent algebraic Riccati equation, and the resulting control is then suboptimal for the electrochemical process. The bilinear model allows for an optimal Kalman–Bucy filter application to reduce external noise. The filtered output is reprocessed through a non‐linear observer in order to obtain a state‐estimation as independent as possible from the bilinear model. Uncertainties on parameters are attenuated through an adaptive control strategy that exploits sensitivity functions in a novel fashion. The whole approach to this control problem can be applied to a fairly general class of non‐linear continuous systems subject to analogous stochastic perturbations. All calculations can be handled on‐line by standard ordinary differential equations integration software. Copyright © 2007 John Wiley & Sons, Ltd.     

Gender,work‐based support and family outcomes

Work‐based support has effects on family outcomes (Thompson, Kirk, & Brown, Stress and Health, 2005, 21, 199–207), suggesting that the effects of work‐based support are transmitted to the family environment through some mediating mechanism. This study examines two potential mediating mechanisms, emotional exhaustion and work interference with family (WIF). It was expected that women would report higher levels of work support, and work support would have a stronger relationship with outcomes for women. Gender as a moderator of the relationships between work support, and emotional exhaustion, WIF, and family environment (family cohesion, family conflict) was tested via regression analyses. Eighty‐one males (43.3 per cent) and 106 females (56.7 per cent), and their spouse/partners participated in the study. Women reported higher levels of coworker support than men, and support from supervisors predicted WIF only for women. Gender did not moderate the work support—family environment relationship. WIF, but not emotional exhaustion, mediated the relationship between supervisor and coworker support, and employee reports of family cohesion. Spouse/partner reports of family environment were not predicted by the study variables. Thus, work support reduces employee negative perceptions of the family environment through reduced work–family stress, and the impact is similar for men and women. Copyright © 2006 John Wiley & Sons, Ltd.     

Stress‐related predictors of optimism in breast cancer survivors

Optimism is a key variable for adjustment in aversive conditions. The purpose of this study was to examine whether optimism is predicted by two stress‐related variables which represent information about self and the environment (i.e. illness‐related stress and self‐efficacy), in a sample of breast cancer survivors. Ninety‐two women who had undergone a mastectomy participated in the study (minimum time elapsed since diagnosis = 3 years). Most participants (51 per cent) reported that at least one of four illness‐related concerns had been quite or very stressful in the past 6 months. Analyses showed that illness‐related stress exerted influence on optimism through coping, whereas self‐efficacy exerted influence both directly and through coping. Stress was predicted by two medical variables (time since diagnosis and time since mastectomy). These findings confirmed our hypothesis that knowledge about personal abilities, as well as about environment difficulties can predict the way a person evaluates future outcomes. This study has significant implications for clinical practice with patients. Copyright © 2007 John Wiley & Sons, Ltd.     

Burnout and self‐employment: a cross‐cultural empirical study

This study examined the differences between full‐time self‐employed and organizationally employed individuals in Canada (n = 248) and Pakistan (n = 306) in terms of overall burnout and its three dimensions (emotional exhaustion, depersonalization and lack of accomplishment), turnover intentions and non‐work satisfaction. Data were collected by means of a structured questionnaire from Canadian employees in Montreal and Pakistani employees in Lahore. One‐way analysis of variance and multivariate analysis of variance were used to analyse the data. The self‐employed reported significantly higher overall burnout, emotional exhaustion, lack of accomplishment, non‐work satisfaction and turnover intention than the organizationally employed in both countries. No significant differences were found between self‐employed and organizationally employed in terms of depersonalization in both countries. Results are discussed in light of previous empirical evidence on self‐employment and the quality of work and non‐work life from cross‐cultural perspectives. Copyright © 2007 John Wiley & Sons, Ltd.