Socioeconomic Disadvantage, Mental Health and Substance Use in Young Men in Emerging Adulthood.

Emerging adulthood is a neglected phase of the life course in health research. Health problems and risk behaviors at this time of life can have long-term consequences for health. The 2016 Lancet Commission on Adolescent Health and Wellbeing reported that the influence of socioeconomic factors was under-researched among adolescents and young adults. Moreover, the influence of socioeconomic factors on health has been little researched specifically in emerging adult men. We aimed to investigate associations between socioeconomic disadvantage and mental health, suicidal behavior, and substance use in young adult Australian men. Logistic regression was used to examine the association between Year 12 (high school) completion and area disadvantage on mental health, suicidal behavior, and substance use in 2,281 young men age 18-25 participating in the Australian Longitudinal Study on Male Health (Ten to Men). In unadjusted analysis both Year 12 non-completion and area disadvantage were associated with multiple adverse outcomes. In adjusted analysis Year 12 non-completion, but not area disadvantage, was associated with poorer mental health, increased odds of suicidal behavior, and substance use. Retaining young men in high school and developing health-promotion strategies targeted at those who do exit education early could both improve young men's mental health and reduce suicidal behavior and substance use in emerging adulthood.

Treatment seeking by employment characteristics among Australian males: a longitudinal study from the Ten to Men study.

OBJECTIVES: Men are less likely to seek treatment for mental health problems than women; however, the structural employment-related factors influencing this relationship are unknown. STUDY DESIGN: This is a prospective cohort study. METHODS: Using the Australian Ten to Men cohort (N = 6447), we examined the relationship between being in a male-dominated occupation and treatment seeking from a mental health professional compared to being in a gender-equal occupation. Models were fit using logistic regression. RESULTS: There was some evidence of a stepwise gradient between male-dominated occupations and treatment seeking for mental health problems. However, results were only significant for the most male-dominated occupations after adjustment (odds ratio [OR] 0.70, 95% confidence interval [CI] 0.52 to 0.94, P = 0.017). We also found evidence that individuals who more strongly adhered to masculine norms had a lower likelihood of treatment seeking (OR = 0.97, 95% CI 0.95 to 0.99, P = 0.004). CONCLUSIONS: This supports the idea that occupational-related factors influence male treatment seeking for mental health problems.

Psychosocial job stressors and thoughts about suicide among males: a cross-sectional study from the first wave of the Ten to Men cohort.

OBJECTIVES: Psychosocial job stressors are known to be associated with poor mental health. This research seeks to assess the relationship between psychosocial working conditions and suicidal ideation using a large dataset of Australian males. STUDY DESIGN: Cross-sectional study. METHODS: Data from wave 1 of the Australian Longitudinal Study on Male Health (Ten to Men) was used to assess the association between suicidal ideation in the past two weeks and psychosocial working conditions using logistic regression. The sample included 11,052 working males. The exposures included self-reported low job control, high job demands, job insecurity and low fairness of pay. We controlled for relevant confounders. RESULTS: In multivariable analysis, persons who were exposed to low job control (odds ratio [OR] 1.15, 95% confidence interval [CI] 1.05-1.26, P = 0.003), job insecurity (OR 1.69, 95% CI 1.44-1.99, P < 0.001) and unfair pay (OR 1.19, 95% CI 1.11-1.27, P < 0.001) reported elevated odds of thoughts about suicide. Males employed casually or on fixed-term contracts reported higher odds of suicidal ideation (OR 1.32, 95% CI 1.09-1.61, P = 0.005). CONCLUSION: Psychosocial job stressors are highly prevalent in the working population and workplace suicide prevention efforts should aim to address these as possible risk factors.

Stress, genetics and epigenetic effects on the neurobiology of suicidal behavior and depression.

Alterations in a number of neurobiological systems have been associated with suicidal behavior including the serotonergic and noradrenergic systems and the hypothalamic-pituitary-adrenal axis. Altered functioning of these systems may stem from both genetic and developmental causes. Adversity in early-life has developmental consequences on these systems that persist into adulthood. Genetic differences may also contribute to alterations in functioning of neurobiological systems. Moreover, the interaction of early-life experiences of adversity and genetic vulnerability is increasingly thought to play a role, including via epigenetic mechanisms.

Beta4 integrin promotes osteosarcoma metastasis and interacts with ezrin.

The development of pulmonary metastasis is the major cause of death in osteosarcoma, and its molecular basis is poorly understood. In this study, we show that beta4 integrin is highly expressed in human osteosarcoma cell lines and tumor samples. Furthermore, highly metastatic MNNG-HOS cells have increased levels of beta4 integrin. Suppression of beta4 integrin expression by shRNA and disruption of beta4 integrin function by transfection of dominant-negative beta4 integrin was sufficient to revert this highly metastatic phenotype in the MNNG-HOS model without significantly affecting primary tumor growth. These findings suggest a role for beta4 integrin expression in the metastatic phenotype in human osteosarcoma cells. In addition, we identified a previously uncharacterized interaction between beta4 integrin and ezrin, a membrane-cytoskeletal linker protein that is implicated in the metastatic behavior of osteosarcoma. The beta4 integrin-ezrin interaction appears to be critical for maintenance of beta4 integrin expression. These data begin to integrate ezrin and beta4 integrin expression into a model of action for the mechanism of osteosarcoma metastases.

Prospective studies of suicidal behavior in major depressive and bipolar disorders: what is the evidence for predictive risk factors?

OBJECTIVE: Prospective studies over the past 30 years have identified an array of predictive indicators for suicidal acts in mood disorders. However, prediction of suicidal behavior remains an elusive goal. This paper reviewed evidence from prospective studies for clinical factors that elevate risk of suicidal acts in that group. METHOD: English language prospective studies of suicidal behavior in major depressive and bipolar disorders were examined. RESULTS: The predictors with the best support were a past history of suicidal behavior and the presence of refractory or recurrent depressions. For other risk factors, there was either not enough data to consider them robust or findings were contradictory. CONCLUSION: Future studies must not only be comprehensive in their inclusion of potentially contributing factors, but must also address their relative importance towards the goal of developing predictive models and enhance suicide prevention efforts.

Acute tachyphylaxis to propofol sedation during ethanol withdrawal.

We treated a patient with a 30-year history of ethanol and benzodiazepine abuse who, on emerging from general anesthesia, was combative and confused. Our working diagnosis was acute ethanol withdrawal, and the patient received intravenous (i.v.) propofol, and midazolam. Initially small doses (10 to 20 mg) of propofol, combined with a midazolam infusion (50 mg/hr), produced sedation. Later, however, the patient became increasingly combative, confused, hypertensive, and tachycardic despite an i.v. propofol infusion at doses up to 1,000 micrograms/kg/min (total propofol dose: 1,755 mg). Immediate sedation was produced by thiopental bolus (500 mg) and i.v. infusion (200 mg/hr). The implication of the patient's initial appropriate response to propofol, followed by the lack of effect when much higher doses were employed, is discussed. While tachyphylaxis has been reported after long-term propofol use, we believe this to be the first case of acute tachyphylaxis.

Review of the afferent neural system of the knee and its contribution to motor learning.

Understanding the afferent neural system of the knee is considered to be vital to rehabilitation planning. An intricate relationship exists involving the afferent neural receptors in the inert and contractile tissues of the knee. Traditional rehabilitation strategies may not exploit this extensive afferent neural system. Closed kinetic chain functional training (CKCFT) may provide a method for more effectively rehabilitating an injured or reconstructed knee. The rationale for CKCFT has traditionally focused on mechanical aspects. Sensorimotor integration through motor learning is believed to be an important component of CKCFT. The purposes of this review are to discuss: 1) the afferent neural system of the knee with emphasis on the mechanoreceptors, 2) the influence of the afferent neural system of the knee on motor learning, and 3) how CKCFT uses the afferent neural system of the knee and motor learning during knee rehabilitation. This review reinforces the use of CKCFT in knee rehabilitation plans.

Effects of electrical and electromagnetic stimulation after anterior cruciate ligament reconstruction.

A need exists to develop new methods of neuromuscular electrical stimulation (NMES) that are both effective and relatively pain-free. The purpose of this pilot study was to determine the effects of both NMES and a new method of electromagnetic (NMES/PEMF) stimulation for reducing girth loss and for reducing pain and muscle weakness of the knee extensor muscles in patients during the first 6 weeks after reconstructive surgery of the anterior cruciate ligament (ACL). Seventeen patients receiving ACL reconstructive surgery participated as a control group (N = 3), as an NMES group (N = 7), and with combined NMES and magnetic field stimulation (NMES/PEMF) (N = 7). Patients receiving NMES/PEMF rated each type of stimulation for perceived pain and were measured for their torque. Torque results revealed a mean decrease of 13.1% for NMES/PEMF patients. The mean percent of thigh girth decreased 8.3% for controls, 0.5% for NMES, and 2.3% for NMES/PEMF patients. The NMES/PEMF patients rated NMES as causing about twice the pain intensity as NMES/PEMF during treatments. As a result of this data, the authors conclude that both NMES and NMES/PEMF are effective in reducing girth loss and that NMES/PEMF is less painful than NMES alone in treating patients after ACL reconstruction.

Effect of variation in the burst and carrier frequency modes of neuromuscular electrical stimulation on pain perception of healthy subjects.

The purpose of this study was to explore the effect of various combinations of burst and carrier frequencies of neuromuscular electrical stimulation (NMES) on subjects' perception of pain intensity associated with induction of high intensity muscle contractions. Twenty-seven healthy volunteers completed the study. After the initial test session, all subjects were treated in three additional sessions with nine combinations of burst frequencies (50, 70, and 90 bursts per second [bps]) and carrier frequencies (2,500, 5,000, and 10,000 Hz) at an NMES amplitude that produced torque equivalent to 50% of maximal voluntary contraction of their quadriceps femoris muscle. Subjects rated each frequency combination for perceived pain intensity with a visual analog scale. The combinations of burst frequencies (50, 70, and 90 bps) and carrier frequencies (2,500 and 5,000 Hz) do not differ from each other in perceived pain intensity but do differ significantly in perceived pain from the combinations of burst frequencies at the carrier frequency of 10,000 Hz. Thus, the clinician may have to try different stimulus combinations on patients at different current training levels to obtain the least individually perceived pain.

Effect of motor neuromuscular electrical stimulation on microvascular perfusion of stimulated rat skeletal muscle.

The purpose of this study was to determine the effect of neuromuscular electrical stimulation (NMES) (2,500-pps sine wave interrupted at 50 bps) on the degree of microvascular perfusion in stimulated skeletal muscle. The tibialis anterior (TA) and extensor digitorum longus (EDL) muscles of 36 male rats were treated with NMES for 30 minutes at current amplitudes sufficient to produce a sustained muscle contraction (motor NMES). Muscle tissue was removed at 0, 5, 10, 15, and 30 minutes after NMES. The perfused vessel/muscle fiber ratio (PV/F) of the stimulated animals at time 0 minutes was greater than that of the unstimulated control animals. A gradual decrease in the magnitude of the PV/F increase was noted over time. Depending on the muscle's fiber-type composition, the PV/F values returned to control levels by 10 to 30 minutes after motor NMES. The results indicate (1) that motor NMES significantly increases the degree of microvascular perfusion in stimulated rat skeletal muscle and (2) that the increased degree of perfusion persists for various lengths of time, depending on the fiber-type composition of the muscle. Thus, if responses in an animal model can be used as indicators of similar human responses, then the results of this study suggest that NMES can be used to increase the degree of microvascular perfusion in human skeletal muscle.

Effect of varying the ratio of electrically induced muscle contraction time to rest time on serum creatine kinase and perceived soreness.

Supported in part by a North Carolina Physical Therapy Association Student Research Grant. The purpose of this study was to determine whether there were differences in the amount of muscle soreness and serum creatine kinase (CK) produced when ratios of electrically induced muscle contraction time to rest time were varied. Fifteen subjects were randomly assigned to one of three groups, each receiving 10, 15-second electrically induced isometric contractions of the quadriceps femoris muscle with rest periods of 10, 30, and 50 seconds between contractions, respectively. The intensity of the contractions were maintained at 30 percent of an individual's maximum voluntary isometric contraction (MVC). Blood samples for serum CK activity, an indicator of muscle damage, and perceived soreness were collected pretreatment, 24, 48, and 72 hours following the single treatment session. Significant increases in the serum CK and perceived soreness ratings were observed in all groups. Postexercise serum CK increases were found to be significantly different between the 10 seconds and the 30-seconds and 50-seconds rest period groups. Clinically, muscle soreness may result from initial trials of neuromuscular electrical stimulation (NMES) with peak amplitudes sufficient to produce contractions equivalent to 30 percent of the MVC. Contraction time to rest ratios of NMES may influence the amount of muscle damage produced. J Orthop Sports Phys Ther 1991,13(6):310-315.

The Effect of One Session of Muscle Soreness-Inducing Weight Lifting Exercise on WBC Count, Serum Creatine Kinase, and Plasma Volume.

The purpose of this study was to assess white blood cell (WBC) count, serum creatine kinase (CK), and plasma volume (PV) changes following a single session of soreness-inducing exercise. Sixteen untrained males, aged 18 to 38 years, were exercised at 80% of one repetition maximum until failure for three sets on seven different weight lifting resistive machines. Measurements were done prior to and up to 84 hours postexercise on: a) delayed onset muscle soreness (DOMS), utilizing a four-point pain scale on seven muscles; b) CK; c) WBC count; and d) PV change, indirectly assessed by hematocrit and hemoglobin. One session of weight lifting exercise was found to produce significant postexercise PV elevations, with the peak change occurring at 36 hours (8.9%, p < .05). Significant elevations in WBC count were found 12 hours postexercise (7900 cells/mul, p < .05) when corrections were made for PV increases. In addition, DOMS and CK were significantly increased postexercise, with the highest levels occurring at 36 hours (9/21 pain scale units, p < .05) and 84 hours (5756 IU/L, p < .001). These results suggest that one session involving high intensity weight lifting exercise may induce muscle soreness and elevate WBC count, CK, and plasma volume. The aggressive initiation of a fitness program can trigger delayed muscle discomfort, a possible inflammatory process, and dilate blood parameters that physical therapists may be monitoring. J Orthop Sports Phys Ther 1991;13(6):316-321.

Effect of Longitudinal Versus Transverse Electrode Placement on Torque Production by the Quadriceps Femoris Muscle during Neuromuscular Electrical Stimulation.

The purpose of this study was to evaluate the effect of electrode placement in relation to muscle design for producing muscle torque when using neuromuscular electrical stimulation (NMES). Thirty-five healthy subjects (19 men, 16 women) participated in this study on a voluntary basis. All subjects were tested for maximum voluntary isometric contraction (MVC) of their dominant quadriceps femoris muscle while seated on an isokinetic dynamometer. NMES to subject tolerance was used while determining the effect of electrode placement (longitudinal and transverse) on the torque. Findings show that the longitudinal electrode position produces significantly more torque than the transverse position when the knee extensor muscles are electrically stimulated by the same current amplitude. Physical therapists should be aware of this technique when using NMES clinically to produce muscle torque. J Orthop Sports Phys Ther 1990;11(11):530-534.

Electrophysiologic responses of human sural nerve to temperature.

The purpose of this study was to assess the conduction, specifically the latency and amplitude of the sensory nerve action potential (SNAP), of the sural nerve as a function of intraneural temperature of the leg. The electrophysiologic responses of the sural nerve were determined at different temperatures in 22 healthy adults. Distal sensory latency and amplitude of the sural SNAP was determined at 1 degree C intervals over a limb temperature range of 23 degrees to 40 degrees C. Limb temperature was monitored with a thermistor probe placed subcutaneously near the sural nerve. Ice bath soaks were used for cooling and infrared radiation for warming the limbs. An analysis of covariance was performed for the SNAP latencies and amplitudes to determine the effect of gender and leg (right or left) at each temperature level. No effect of gender or leg on neural conduction was detected in individual subjects. A regression analysis was then used on pooled data to determine the effect of temperature on sural SNAP latency and amplitude. An inverse linear change in the latency of sural SNAP was observed over the temperature ranges used. Mean latency increased 0.1 msec per 1 degree C increase in subcutaneous temperature. A direct relationship between amplitude of the SNAP and temperature was determined. Mean amplitude increased 0.3 muV per 1 degree C increase in subcutaneous temperature. The results of this study support previous reports, which state that SNAP latency is indirectly related to the intraneural temperature. Clinical electromyographers must monitor the temperature of the lower leg and foot whenever sensorineural conduction of the lower limbs is performed.

Comparison of selected pulse frequencies from two different electrical stimulators on blood flow in healthy subjects.

The purpose of this study was to measure the effects of selected frequencies from two different pulsed electrical stimulators on blood flow, blood pressure, and heart rate. Each of 30 healthy subjects attended 10 study sessions: 1 torque-testing session, 1 control session consisting of no electrical stimulation (ES), and 8 sessions of ES. All subjects received ES at an intensity sufficient to produce torque equal to 15% of the predetermined maximal voluntary contraction of their right quadriceps femoris muscle. The results of a multivariate analysis of variance showed that changes in blood flow during and after ES were dependent on pulse frequency but independent of stimulator type. Further analysis showed significant increases in blood flow with ES using 10, 20, and 50 pulses per second compared with 1 pulse per second. Inconsistent changes in blood pressure and heart rate were produced by ES. Based on the results of this study, effective clinical use of ES for promoting arterial blood flow to muscle would involve pulsed frequencies of 10 to 50 pulses per second.

Effects of high voltage pulsed electrical stimulation on blood flow.

The purpose of this study was to determine whether high voltage electrical stimulation would increase blood flow to skeletal muscle in healthy subjects. Subjects were assigned to one of three groups: 1) an Electrical Stimulation (ES) Group (n = 16), 2) an Exercise (EX) Group (n = 14), or 3) a Control Group (n = 8). Isometric contractions were induced electrically at 30 Hz in the ES Group and performed volitionally in the EX Group for five minutes at intensities of 10% and 30% of predetermined maximal voluntary isometric contraction (MVC) efforts. Blood flow, heart rate, and blood pressure were unaffected in the ES Group, but blood flow and systolic blood pressure increased and decreased, respectively, for the EX Group at 30% of MVC. High voltage stimulation at a pulse rate of 30 Hz and at intensities needed to evoke contractions at 10% and 30% of MVC for plantar flexion did not increase blood flow at the popliteal artery.

Augmenting voluntary torque of healthy muscle by optimization of electrical stimulation.

The purpose of this study was to evaluate the ability of electrical stimulation (2,500-Hz sine waves, interrupted for 50 pulsed bursts per second) to improve muscle torque using low-dosage training characteristics. Fifteen healthy subjects (9 men, 6 women), 20 to 32 years of age, participated in the experiment. All subjects received electrical stimulation of the right anterior thigh musculature while their left leg served as the control. Electrical stimulation was repeated eight times per session, each stimulation producing isometric torque equal to 50% of the subject's maximum voluntary isometric contraction. The sessions were repeated twice a week over a period of five weeks. Results showed that electrical stimulation, when used with the specified low-dosage training characteristics of this study, will augment quadriceps femoris muscle torque of men.