Sensitivity of 24-h EMG duration and intensity in the human vastus lateralis muscle to threshold changes.

Few studies have quantified lower limb muscle activity over 24 h using electromyographic signals (EMG). None have described the changes in EMG duration and intensity when data are analyzed with different thresholds. Continuous bilateral EMG recordings were made from vastus lateralis (VL) in 10 subjects (20-48 yr) for 24 h. Before and after this recording, voluntary quadriceps forces and VL EMG at 25%, 50%, 75%, and 100% of the maximal voluntary contraction (MVC), percentage voluntary activation (twitch interpolation), and compound action potentials (M-waves) were recorded. Offline, the 24-h EMG integrals (IEMG, 10-ms time constant) were normalized to the MVC IEMG. Total EMG duration and mean IEMG ranged from 1-3 h and 3.2-12.1% MVC, respectively, when the data were analyzed using the baseline (+3 SD) as threshold. When analysis was done with progressively higher thresholds, from baseline up to 4% MVC, the total EMG duration declined curvilinearly. In some cases the decline in duration was 50-60% for a 1% MVC threshold increment. The mean 24-h IEMG increased by 1.5-2% MVC for each 1% MVC threshold increment. Hence, a small change in the analysis threshold may result in large changes in 24-h EMG duration but moderate changes in mean IEMG. Our findings suggest that VL was active for a short amount of time and at low intensities over 24 h.

Alcohol use among older adults.

Alcohol use problems among older adults have been called the "invisible epidemic." As the population of older adults continues to grow, there is an increased need to reexamine alcohol use in this population. The authors provide an overview on alcohol use in the over-60 age group. The main areas of focus included research on the prevalence of drinking in that population, as well as comments on the best practices in assessment and psychological treatment. Several screening assessments have been recommended for use with older adults, such as the CAGE questionnaire, Michigan Alcohol Screening Test-Geriatric version, Alcohol-Related Problems Survey, and the Alcohol Use Disorders Identification Test. The authors note age-appropriate psychological treatment interventions that include brief interventions, family interventions, motivational counseling, and cognitive behavioral therapies. Barriers to assessment and treatment are also discussed.

Inflammatory cytokine concentrations are elevated in seminal plasma of men with spinal cord injuries.

The semen of most men with spinal cord injury (SCI) contains sperm with abnormally low motility. Studies suggest that the seminal plasma is the source of this condition. The seminal plasma of men with SCI contains an abnormally high number of white blood cells (WBC), specifically, activated T cells. It is known that activated T cells secrete cytokines and elevated concentrations of cytokines can be harmful to sperm. It is not known if the seminal plasma of men with SCI contains elevated concentrations of cytokines. The purpose of this study was to determine if the seminal plasma of men with SCI contained elevated concentrations of cytokines. Using the method of enzyme-linked immunosorbant assay (ELISA), ten cytokines were measured in the seminal plasma of men with SCI as well as healthy non-SCI control subjects. The cytokines of interest were grouped according to Th1 effector functions: interleukin 1 beta, interleukin 2, interleukin 12, tumor necrosis factor alpha, tumor necrosis factor beta, interferon gamma (IL1 beta, IL2, IL12, TNF alpha, TNF beta, INF gamma, respectively) and Th2 effector functions: interleukin 4, interleukin 6, interleukin 10, transforming growth factor beta 1 (IL4, IL6, IL10, TGF beta 1, respectively). The results showed a predominance of Th1 versus Th2 cytokine production in the seminal plasma of men with SCI compared with that of control subjects. This finding suggests an immunologic basis for infertility as a possible avenue of investigation in these men.

Cytofluorographic identification of activated T-cell subpopulations in the semen of men with spinal cord injuries.

The semen of most men with spinal cord injury (SCI) contains an abundance of leukocytes. It is not known if this leukocytospermia contributes to the abnormally low sperm motility observed in many of these men. Our study used flow cytometry to identify the leukocyte population in the semen of 12 men with SCI compared to 8 healthy age-matched control subjects. The results showed that, compared to control subjects, the semen of men with SCI had increased numbers of mature granulocytes and lymphocytes. The largest proportion of the leukocytes consisted of lymphocytes, and immunophenotypic analysis showed that the greater fraction were T cells, many of which coexpressed human leukocyte antigen HLA-DR and CD25, suggesting they were in an "activated" state. No significant B-cell population was evident. Our finding of immunologically active leukocytes is a significant step in understanding the relationship of leukocytospermia and decreased sperm motility in the semen of men with SCI.

Semen retrieval in men with spinal cord injury is improved by interrupting current delivery during electroejaculation.

PURPOSE: Based on the findings of a previous study of pressure differentials in the external and internal urinary sphincters during electroejaculation we determined whether semen retrieval in men with spinal cord injury would be improved by interrupting current delivery during electroejaculation. MATERIALS AND METHODS: We tested continuous versus interrupted current delivery in the same group of 12 men with spinal cord injury. Patients underwent a mean of 4 randomly assigned continuous or interrupted trials 4 to 8 weeks apart. Antegrade and retrograde semen parameters were analyzed per trial. Multiple trials of each method per patient were averaged and semen parameters by the continuous and interrupted methods were compared. RESULTS: Interrupted delivery resulted in significantly greater mean antegrade volume versus continuous delivery (2 versus 0.9 cc). In this antegrade fraction mean total sperm count and mean total motile sperm was higher for interrupted (130 million and 35 million) versus continuous (79 million and 26 million, respectively) delivery. The mean retrograde total sperm count was 4-fold higher for continuous (120 million) versus interrupted (29 million) delivery. In the total ejaculate of the combined antegrade and retrograde fractions the mean total sperm count and mean total motile sperm were not significantly different for the 2 methods. CONCLUSIONS: Each method resulted in a similar mean total sperm count and total motile sperm in the total ejaculate but a higher proportion of sperm was found in the antegrade fraction using the interrupted method. We recommend interrupted current delivery as the technique of choice when electroejaculation is performed to obtain sperm for fertilization.