Cigarettes and Straws: Late Positive Potential Modulation in Mental Illness and Nicotine Addiction

Tobacco use remains a major preventable cause of death worldwide, accumulating billions of dollars in healthcare spending annually in the U.S. alone. Evidence has found that among those addicted, individuals suffering with psychiatric illnesses are disproportionally abusing. To assess this disparity, our study observed event related potential (ERP) responses recorded with electroencephalogram (EEG) in chronic smokers with (MI; n=6) and without mental illness (NMI; n=6). We found that the MI group alone presented heightened late positive potential (LPP) responses while processing cigarette (addictive) stimuli compared to neutral images (t-value = 3.11 at Cz, 3.92 at Pz). Our study illustrates the significance of the LPP as a promising biomarker to assess tobacco addiction in individuals facing mental illness.

Non-Invasive, Cost-Effective, Early Diagnosis of Mild Cognitive Impairment in an Outpatient Setting: Pilot Study

Mild cognitive impairment (MCI) and Alzheimer's Disease (AD) affect millions worldwide, yet no curative treatments for these neuro-degenerative disorders have been developed to date. The current study aims to propose a noninvasive, cost-effective, early diagnostic protocol for individuals suffering with MCI in an outpatient setting. Elderly participants (n=11) were screened for MCI utilizing the Montreal Cognitive Assessment (MoCA) questionnaire preceding a visual stimuli task. Participants were presented with facial stimuli to elicit event related potentials (ERP) while their cortical activity was recorded utilizing electroencephalogram (EEG). Combining regional neurophysiological biomarkers into a multidimensional feature space allowed for differentiation between healthy and MCI participants based on their respective MoCA scores. This study illustrates the feasibility of recording reliable EEG in an outpatient setting while presenting a novel method for diagnosing MCI in elderly (age >60) populations.

mTOR regulates peripheral nerve response to tensile strain

While excessive tensile strain can be detrimental to nerve function, strain can be a positive regulator of neuronal outgrowth. We used an in vivo rat model of sciatic nerve strain to investigate signaling mechanisms underlying peripheral nerve response to deformation. Nerves were deformed by 11% and did not demonstrate deficits in compound action potential latency or amplitude during or after 6 h of strain. As revealed by Western blotting, application of strain resulted in significant upregulation of mammalian target of rapamycin (mTOR) and S6 signaling in nerves, increased myelin basic protein (MBP) and β-actin levels, and increased phosphorylation of neurofilament subunit H (NF-H) compared with unstrained (sham) contralateral nerves (P < 0.05 for all comparisons, paired two-tailed t-test). Strain did not alter neuron-specific β3-tubulin or overall nerve tubulin levels compared with unstrained controls. Systemic rapamycin treatment, thought to selectively target mTOR complex 1 (mTORC1), suppressed mTOR/S6 signaling, reduced levels of MBP and overall tubulin, and decreased NF-H phosphorylation in nerves strained for 6 h, revealing a role for mTOR in increasing MBP expression and NF-H phosphorylation, and maintaining tubulin levels. Consistent with stretch-induced increases in MBP, immunolabeling revealed increased S6 signaling in Schwann cells of stretched nerves compared with unstretched nerves. In addition, application of strain to cultured adult dorsal root ganglion neurons showed an increase in axonal protein synthesis based on a puromycin incorporation assay, suggesting that neuronal translational pathways also respond to strain. This work has important implications for understanding mechanisms underlying nerve response to strain during development and regeneration.NEW & NOTEWORTHY Peripheral nerves experience tensile strain (stretch) during development and movement. Excessive strain impairs neuronal function, but moderate strains are accommodated by nerves and can promote neuronal growth; mechanisms underlying these phenomena are not well understood. We demonstrated that levels of several structural proteins increase following physiological levels of nerve strain and that expression of a subset of these proteins is regulated by mTOR. Our work has important implications for understanding nerve development and strain-based regenerative strategies.

Knockout of STAT3 in skeletal muscle does not prevent high-fat diet-induced insulin resistance

Objective

Increased signal transducer and activator of transcription 3 (STAT3) signaling has been implicated in the development of skeletal muscle insulin resistance, though its contribution, in vivo, remains to be fully defined. Therefore, the aim of this study was to determine whether knockout of skeletal muscle STAT3 would prevent high-fat diet (HFD)-induced insulin resistance.

Methods

We used Cre-LoxP methodology to generate mice with muscle-specific knockout (KO) of STAT3 (mKO). Beginning at 10 weeks of age, mKO mice and their wildtype/floxed (WT) littermates either continued consuming a low fat, control diet (CON; 10% of calories from fat) or were switched to a HFD (60% of calories from fat) for 20 days. We measured body composition, energy expenditure, oral glucose tolerance and in vivo insulin action using hyperinsulinemic-euglycemic clamps. We also measured insulin sensitivity in isolated soleus and extensor digitorum longus muscles using the 2-deoxy-glucose (2DOG) uptake technique.

Results

STAT3 protein expression was reduced ∼75–100% in muscle from mKO vs. WT mice. Fat mass and body fat percentage did not differ between WT and mKO mice on CON and were increased equally by HFD. There were also no genotype differences in energy expenditure or whole-body fat oxidation. As determined, in vivo (hyperinsulinemic-euglycemic clamps) and ex vivo (2DOG uptake), skeletal muscle insulin sensitivity did not differ between CON-fed mice, and was impaired similarly by HFD.

Conclusions

These results demonstrate that STAT3 activation does not underlie the development of HFD-induced skeletal muscle insulin resistance.

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Loss of STAT3 in skeletal muscle does not effect whole body energy expenditure in mice.

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Mice with knockout of STAT3 in skeletal muscle (mKO) develop glucose intolerance with HFD feeding similar to littermate controls.

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HFD-induced insulin resistance in skeletal muscle is not prevented by knockout of STAT3.

High-fat diet-induced impairment of skeletal muscle insulin sensitivity is not prevented by SIRT1 overexpression

Skeletal muscle sirtuin 1 (SIRT1) expression is reduced under insulin-resistant conditions, such as those resulting from high-fat diet (HFD) feeding and obesity. Herein, we investigated whether constitutive activation of SIRT1 in skeletal muscle prevents HFD-induced muscle insulin resistance. To address this, mice with muscle-specific overexpression of SIRT1 (mOX) and wild-type (WT) littermates were fed a control diet (10% calories from fat) or HFD (60% of calories from fat) for 12 wk. Magnetic resonance imaging and indirect calorimetry were used to measure body composition and energy expenditure, respectively. Whole body glucose metabolism was assessed by oral glucose tolerance test, and insulin-stimulated glucose uptake was measured at a physiological insulin concentration in isolated soleus and extensor digitorum longus muscles. Although SIRT1 was significantly overexpressed in muscle of mOX vs. WT mice, body weight and percent body fat were similarly increased by HFD for both genotypes, and energy expenditure was unaffected by diet or genotype. Importantly, impairments in glucose tolerance and insulin-mediated activation of glucose uptake in skeletal muscle that occurred with HFD feeding were not prevented in mOX mice. In contrast, mOX mice showed enhanced postischemic cardiac functional recovery compared with WT mice, confirming the physiological functionality of the SIRT1 transgene in this mouse model. Together, these results demonstrate that activation of SIRT1 in skeletal muscle alone does not prevent HFD-induced glucose intolerance, weight gain, or insulin resistance.

NAD(+)/NADH and skeletal muscle mitochondrial adaptations to exercise

The pyridine nucleotides, NAD(+) and NADH, are coenzymes that provide oxidoreductive power for the generation of ATP by mitochondria. In skeletal muscle, exercise perturbs the levels of NAD(+), NADH, and consequently, the NAD(+)/NADH ratio, and initial research in this area focused on the contribution of redox control to ATP production. More recently, numerous signaling pathways that are sensitive to perturbations in NAD(+)(H) have come to the fore, as has an appreciation for the potential importance of compartmentation of NAD(+)(H) metabolism and its subsequent effects on various signaling pathways. These pathways, which include the sirtuin (SIRT) proteins SIRT1 and SIRT3, the poly(ADP-ribose) polymerase (PARP) proteins PARP1 and PARP2, and COOH-terminal binding protein (CtBP), are of particular interest because they potentially link changes in cellular redox state to both immediate, metabolic-related changes and transcriptional adaptations to exercise. In this review, we discuss what is known, and not known, about the contribution of NAD(+)(H) metabolism and these aforementioned proteins to mitochondrial adaptations to acute and chronic endurance exercise.

NAD(+)/NADH and skeletal muscle mitochondrial adaptations to exercise

The pyridine nucleotides, NAD(+) and NADH, are coenzymes that provide oxidoreductive power for the generation of ATP by mitochondria. In skeletal muscle, exercise perturbs the levels of NAD(+), NADH, and consequently, the NAD(+)/NADH ratio, and initial research in this area focused on the contribution of redox control to ATP production. More recently, numerous signaling pathways that are sensitive to perturbations in NAD(+)(H) have come to the fore, as has an appreciation for the potential importance of compartmentation of NAD(+)(H) metabolism and its subsequent effects on various signaling pathways. These pathways, which include the sirtuin (SIRT) proteins SIRT1 and SIRT3, the poly(ADP-ribose) polymerase (PARP) proteins PARP1 and PARP2, and COOH-terminal binding protein (CtBP), are of particular interest because they potentially link changes in cellular redox state to both immediate, metabolic-related changes and transcriptional adaptations to exercise. In this review, we discuss what is known, and not known, about the contribution of NAD(+)(H) metabolism and these aforementioned proteins to mitochondrial adaptations to acute and chronic endurance exercise.

Gene expression alterations at baseline and following moderate exercise in patients with Chronic Fatigue Syndrome and Fibromyalgia Syndrome

OBJECTIVES

To determine mRNA expression differences in genes involved in signalling and modulating sensory fatigue, and muscle pain in patients with chronic fatigue syndrome (CFS) and fibromyalgia syndrome (FM) at baseline, and following moderate exercise.

DESIGN

Forty-eight patients with CFS only, or CFS with comorbid FM, 18 patients with FM that did not meet criteria for CFS, and 49 healthy controls underwent moderate exercise (25 min at 70% maximum age-predicted heart rate). Visual-analogue measures of fatigue and pain were taken before, during and after exercise. Blood samples were taken before and 0.5, 8, 24 and 48 h after exercise. Leucocytes were immediately isolated from blood, number coded for blind processing and analyses and flash frozen. Using real-time, quantitative PCR, the amount of mRNA for 13 genes (relative to control genes) involved in sensory, adrenergic and immune functions was compared between groups at baseline and following exercise. Changes in amounts of mRNA were correlated with behavioural measures and functional clinical assessments.

RESULTS

No gene expression changes occurred following exercise in controls. In 71% of patients with CFS, moderate exercise increased most sensory and adrenergic receptor's and one cytokine gene's transcription for 48 h. These postexercise increases correlated with behavioural measures of fatigue and pain. In contrast, for the other 29% of patients with CFS, adrenergic α-2A receptor's transcription was decreased at all time-points after exercise; other genes were not altered. History of orthostatic intolerance was significantly more common in the α-2A decrease subgroup. FM-only patients showed no postexercise alterations in gene expression, but their pre-exercise baseline mRNA for two sensory ion channels and one cytokine were significantly higher than controls.

CONCLUSIONS

  At least two subgroups of patients with CFS can be identified by gene expression changes following exercise. The larger subgroup showed increases in mRNA for sensory and adrenergic receptors and a cytokine. The smaller subgroup contained most of the patients with CFS with orthostatic intolerance, showed no postexercise increases in any gene and was defined by decreases in mRNA for α-2A. FM-only patients can be identified by baseline increases in three genes. Postexercise increases for four genes meet published criteria as an objective biomarker for CFS and could be useful in guiding treatment selection for different subgroups.

Administration of thiazolidinediones for neuroprotection in ischemic stroke: a pre-clinical systematic review

Thiazolidinediones (TZDs) may prevent or attenuate CNS injury arising from an ischemic event. We performed meta-analysis of experimental studies in which a TZD (either rosiglitazone or pioglitazone) was administered in a rodent model of focal or global cerebral ischemia. Infarct volume was the primary endpoint for analysis of drug efficacy, and neurological outcome was also assessed. We identified 31 studies through the use of PubMed and Embase, 22 of which met our pre-specified inclusion criteria and were analyzed with the Cochrane Review Manager software. Treatment with TZDs decreased infarct volume and improved neurological outcome regardless of study quality, dose timing, or ischemia model (transient or permanent). Rosiglitazone and pioglitazone were similarly effective in reducing infarct volume and protecting neurologic function. Importantly, the collective data suggest that pre-treatment with a TZD is not required for neuroprotection, although additional studies are clearly needed to define the breadth of the therapeutic window. The data warrant further studies into the potential acute use of TZDs for ischemic stroke therapy in the general population.

Brain activation in multiple sclerosis: a BOLD fMRI study of the effects of fatiguing hand exercise

Background

Multiple sclerosis (MS) patients experience fatigue as a chronic symptom that decreases quality of life. Commonly, fatigue in MS patients is manifested as decreased motor function during or after physical activity and is associated with changes in brain metabolism.

Objective

To determine brain activation patterns in MS patients and healthy controls during a simple motor task before and after fatiguing hand-grip exercise.

Methods

Functional magnetic resonance imaging (fMRI) scans were conducted on 10 MS patients and 13 healthy controls during 4-finger flexion and extension in rested and fatigued states.

Results

Before the fatigue protocol, MS patients had greater activation in the contralateral primary motor cortex, insula, and cingulate gyrus than controls. Following fatiguing exercise, controls showed increased activation of precentral gyrus and insula while patients did not show any activation increases and actually decreased activity to the insula.

Conclusion

Results indicate that before fatiguing exercise, MS patients marshaled more brain activation compared to controls, which may represent functionally adaptive changes in response to demyelination. This increased activation may suggest that patients require more effort to perform even simple motor tasks, possibly because peripheral or central signals for fatigue are chronically enhanced. When fatigued further by muscle contraction, brain activation cannot be further increased.

Motor-evoked potentials in response to fatiguing grip exercise in multiple sclerosis patients

OBJECTIVE

This study examined central and peripheral effects of fatiguing exercise (3 min maximal grip) in healthy controls (n=10) and multiple sclerosis (MS) subjects with weakness, MS-W (n=16) and normal motor function, MS-NM (n=16) in the studied extremity.

METHOD

Transcranial magnetic stimulation (TMS) was used to assess resting and facilitated motor-evoked potentials (MEPs) of abductor pollicus brevis (APB) and flexor carpi radialis (FCR) muscles before and after fatiguing exercise. Exercise-induced depletion and recovery of phosphocreatine (PCr) were measured using (31)P magnetic resonance spectroscopy ((31)PMRS) in FCR.

RESULTS AND CONCLUSION

MS subjects demonstrated significantly lower peak force and a faster decline in force than controls. Contralateral muscle activation (hand grip) before the fatigue protocol resulted in significantly increased MEP amplitudes in all groups. Contralateral hand grip following fatiguing exercise resulted in significantly higher MEP amplitudes in controls and MS-NM subjects, but not MS-W subjects. Fatiguing exercise resulted in prolonged central motor conduction time (CMCT) in MS subjects, but not controls. No group differences in PCr depletion or resynthesis were observed. All groups demonstrated significant post-exercise depression (PED) of MEP amplitude that persisted beyond the time course of PCr recovery, indicating fatigue was central in origin. MS subjects were less able than controls to increase cortical excitability using contralateral muscle activation following fatiguing exercise, possibly indicating impaired conduction in the corpus callosum.

Effect of precooling on physical performance in multiple sclerosis

Many individuals with MS experience heat sensitivity that may be associated with transient increases in the frequency of clinical signs and symptoms. Although physical activity may be beneficial for those with MS, induced thermal loads may preclude participation in exercise and other daily activities. This project was designed to evaluate the effects of precooling on physical function. Six thermosensitive MS patients were studied. Participants performed a graded exercise test to determine maximal oxygen uptake (VO2max) on a combined arm-leg ergometer. Thermal load was induced by 30 min of exercise under noncooled and precooled conditions at a workrate corresponding to 60% VO2max. Precooling consisted of 30 min lower body immersion in 16 - 17 degrees C water. Fatigue and 25-ft walk performance were assessed before, immediately after, and 30 min following exercise. No treatment differences in VO2 were observed. Rectal temperature, heart rate, and rating of perceived exertion (RPE) were significantly lower during the precooled exercise trial compared to the noncooled trial. Immediately following exercise, 25-ft walk performance and fatigue scores showed significantly greater deterioration in the noncooled condition. Precooling was effective in preventing gains in core temperature with physical work and may allow heat-sensitive individuals with MS to exercise with greater physical comfort.

Recommendations for physical activity in patients with multiple sclerosis

For many years, patients with multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system, have been advised to avoid exercise. MS is believed to be autoimmune in origin, mediated by activated T cells which penetrate the blood-brain barrier and attack myelin. The pathophysiology, with respect to function is an impairment of saltatory conduction, specifically, slowing of conduction speed and/or conduction block. Symptoms can temporarily worsen on exposure to heat or during physical exercise. Exercise programmes must be designed to activate working muscles but avoid overload that results in conduction block. Fatigue, often severe, affects about 85% of MS patients and, along with motor and sensory symptoms, results in decreased mobility and reduced quality of life. Physical activity and recreation are reduced in patients with MS. Before developing recommendations, physical activity patterns and the physical effects of MS should be assessed in individual patients. Patients may then be functionally classified. Physical activity can also be classified in a pyramid structure, with the most basic functions forming the base and the most integrated functions on top. The muscular fitness pyramid progresses through passive range of motion, active resistive, specific strengthening and integrated strength exercises Overall physical activity may be increased according to functional level by performing activities of daily living, incorporating inefficiencies into daily living, pursuing more active recreation and eventually developing a structured exercise programme. The importance of the proper exercise environment, balance and coordination issues and factors related to adherence are discussed.

The physiological effects of beverage ingestion during cross country ski training in elite collegiate skiers

The purpose of this study was to investigate the effects of beverage ingestion on fluid balance during 1.5 hr of low intensity cross country skiing. In Part I, 6 skiers drank water ad libitum during ski training. In Part II, 10 skiers were matched by body weight (BW) and assigned to ingest 2.5 ml.kg-1 BW of water or a carbohydrate/electrolyte (CE) beverage every 2.5 km. Skiing speed averaged 11.5 km.hr-1 for 90 min around a 5 km groomed track. Following 20 min of seated rest, blood samples were collected immediately before and approximately 30 min after skiing. Part I data indicated that subjects ingested 576 +/- 189 ml of fluid and produced 266 +/- 205 ml of urine; BW, plasma and urine osmolality, and plasma protein decreased significantly. In Part II, the CE group produced less urine (135u75 vs. 450 +/- 262 ml) and had smaller decreases in plasma osmolality (-1.0 +/- 1.0 vs. -7.0 +/- 2.4 mOsm.kg H2O) and protein (-0.11 +/- 08 vs. -0.42 +/- 0.24 gL-1) than the water group. No differences were observed for BW loss, % change in PV, FWC, or change in urine osmolality. It was concluded that ad lib water ingestion was inadequate to minimize fluid balance disruption. Plain water ingestion also led to significant dilution of the plasma and increased urine output. However, the ingestion of CE led to attenuation of fluid balance disruption, presumably due to the maintenance of osmotic balance in the plasma.

Impact of aerobic training on fitness and quality of life in multiple sclerosis

Fifty-four multiple sclerosis (MS) patients were randomly assigned to exercise (EX) or nonexercise (NEX) groups. Before and after 15 weeks of aerobic training, aspects of fitness including maximal aerobic capacity (VO2max), isometric strength, body composition, and blood lipids were measured. Daily activities, mood, fatigue, and disease status were measured by the Profile of Mood States (POMS), Sickness Impact Profile (SIP), Fatigue Severity Scale (FSS), and neurological examination. Training consisted of 3 x 40-minute sessions per week of combined arm and leg ergometry. Expanded Disability Status Scale (EDSS) scores were unchanged, except for improved bowel and bladder function in the EX group. Compared with baseline, the EX group demonstrated significant increases in VO2max, upper and lower extremity strength, and significant decreases in skinfolds, triglyceride, and very-low-density lipoprotein (VLDL). For the EX group, POMS depression and anger scores were significantly reduced at weeks 5 and 10, and fatigue was reduced at week 10. The EX group improved significantly on all components of the physical dimension of the SIP and showed significant improvements for social interaction, emotional behavior, home management, total SIP score, and recreation and past times. No changes were observed for EX or NEX groups on the FSS. Exercise training resulted in improved fitness and had a positive impact on factors related to quality of life.

Physiological aspects and injury in elite Alpine skiers

Alpine skiing requires aerobic and anaerobic power, muscular strength, and a variety of complex motor abilities including quickness, agility, balance and coordination. There is evidence of variability in physical characteristics between skiers of different events. Generally, successful alpine competitors are taller and heavier than in the past. Greater size, specifically lean mass, may be related to technique changes because of the advent of breakaway poles. Aerobic power, although important, does not discriminate competitors of varying ability categories. Aerobic power is more likely to be a result of conditioning for alpine skiing rather than a profound requirement of the sport. Anaerobic power is important for skiing and both laboratory and field power tests correlate well with performance. Tests that measure explosive and sustained anaerobic power such as the Wingate, vertical jump, 60-second repeated jump, and Margaria-Kalamen stair run are valuable in assessing skiers. On-snow lactate and oxygen consumption measurements further substantiate the need for high anaerobic power. Alpine skiers have very high leg strength compared with other athletes. Isokinetic testing has been used to evaluate dynamic leg strength in skiers, but little is known about high speed dynamic or eccentric strength capabilities. A new mechanism of knee injury that is associated with tibial acceleration has been identified in competitive alpine skiers. A release binding that is sensitive to physiological factors in addition to release forces should be developed. Strength profiling of skiers may also be valuable in evaluating injury risk.

Human infection by genetically diverse SIVSM-related HIV-2 in west Africa

Our understanding of the biology and origins of human immunodeficiency virus type 2 (HIV-2) derives from studies of cultured isolates from urban populations experiencing epidemic infection and disease. To test the hypothesis that such isolates might represent only a subset of a larger, genetically more diverse group of viruses, we used nested polymerase chain reactions to characterize HIV-2 sequences in uncultured mononuclear blood cells of two healthy Liberian agricultural workers, from whom virus isolation was repeatedly unsuccessful, and from a culture-positive symptomatic urban dweller. Analysis of pol, env and long terminal repeat regions revealed the presence of three highly divergent HIV-2 strains, one of which (from one of the healthy subjects) was significantly more closely related to simian immunodeficiency viruses infecting sooty mangabeys and rhesus macaques (SIVSM/SIVMAC) than to any virus of human derivation. This subject also harboured multiply defective viral genotypes that resulted from hypermutation of G to A bases. Our results indicate that HIV-2, SIVSM and SIVMAC comprise a single, highly diverse group of lentiviruses which cannot be separated into distinct phylogenetic lineages according to species of origin.

Non-specific abdominal pain: the resource implications

Non-specific abdominal pain (NSAP) is responsible for a significant proportion of emergency surgical admissions with resultant resource implications. The extent of the problem was assessed in a consecutive group of 100 patients, aged between 15 and 35 years, admitted with lower abdominal pain to one general surgical firm. No less than 67 of these patients (67%) were diagnosed as having NSAP (13.29% of all general surgical admissions), most (75%) being female and having a mean hospital stay of 4.1 days. Only 11 patients (11%) had appendicitis and the remaining 22 had miscellaneous gynaecological, urological or gastrointestinal problems. Detailed analysis of the resources used revealed that the mean cost to the NHS of each case of NSAP was 807 pounds, the bulk of which was attributable to the hospital stay. Wider assessment of the problem (by means of postal questionnaire) suggests that the cost to the NHS in Wales is in the region of 6 million pounds per year and may be over 100 million pounds per year in the UK as a whole.

Physiological comparison of international, national and regional alpine skiers

The purpose of this study was to evaluate the predictive power of physiological tests in categorizing competitive alpine skiers. Sixty-one subjects (30 female and 31 male) were classified into three levels: international, national, and regional on the basis of past competition results. Hydrostatic weighing, maximal cycling, Wingate, 60-s repeated jump, and vertical jump tests were used to assess body composition, aerobic and anaerobic power, respectively. MANOVA revealed a significant group by gender interaction (Hotellings T, p less than .001), and main effects of gender and group (p less than .001). Discriminant analyses performed separately for male and female groups determined which variables were responsible for differences and resulted in selection of the following variables for classification of the men: average work from the repeated jump, absolute power for the vertical jump, and Wingate endurance. For the women, average work from the repeated jump, absolute and relative vertical jump power, absolute maximum Wingate power, and relative repeated jump power were most important. Fat-free mass was a powerful predictor for both sexes because of its strong relationship (r greater than 0.85) with power results. Aerobic power was not useful in group classification. In conclusion, physiological tests of anaerobic power and fat-free mass were the best predictors of group membership.

Improvement in severe onchocercal skin disease after a single dose of ivermectin

PURPOSE

Skin disease is the most common clinically important manifestation of onchocerciasis. Ivermectin, a newly available drug, is well tolerated and effective in Onchocerca volvulus infection. However, little information is available regarding its effect on onchocercal skin disease. The purpose of this study was to examine, in patients with well-characterized onchodermatitis, the effect of a single dose of ivermectin.

SUBJECTS AND METHODS

Twenty-one persons with severe onchodermatitis were followed over a 6-month period. In order to evaluate the effect of ivermectin on their skin lesions, photographic transparencies were made before treatment and at 3 and 6 months after treatment. These were then evaluated in a blinded fashion.

RESULTS

Following a single dose of 150 micrograms/kg, there was a significant improvement in dermatitis in the first 3 months after treatment. All 14 persons with the worst skin disease showed improvement. The drug had no demonstrable effect on depigmented lesions over the period of observation. Treatment was well tolerated.

CONCLUSION

Single-dose ivermectin shows promise as the first acceptable treatment for severe onchocercal dermatitis.

Ocular manifestations of onchocerciasis in a rain forest area of west Africa

The epidemiology and natural history of onchocerciasis and its ocular complications in rain forest areas are poorly understood. The present study was conducted on a rubber plantation in a hyperendemic area in the rain forest of Liberia, West Africa, where 800 persons were examined. The prevalence of infection was 84% overall 29% had intraocular microfilariae, and 2.4% were blind in one or both eyes. Onchocerciasis was the cause of all binocular blindness and one-third of all visual impairment. Over half of the visual impairment caused by onchocerciasis was due to posterior segment diseases. Chorioretinal changes were present in 75% of people, and included intraretinal pigment clumping in 52% and retinal pigment epithelium atrophy in 32%. Atrophy of the retinal pigment epithelium was associated with increasing age and severity of infection. Intraretinal pigment was strongly associated with anterior uveitis. There was a strong correlation between uveitis and the inflammatory chorioretinal sequelae: retinitis, intraretinal pigment, subretinal fibrosis, and optic neuropathy. These findings indicate that considerable visual impairment associated with rain forest onchocerciasis is common and is due largely to chorioretinal disease.

A comparison of 6-, 12-, and 24-monthly dosing with ivermectin for treatment of onchocerciasis

This study was designed to examine the optimal dose and interval of administration of ivermectin, the now-accepted drug of choice for onchocerciasis. Two hundred Liberians with Onchocerca volvulus infection received 100, 150, or 200 micrograms/kg ivermectin or placebo and were followed for 36 months. The reaction after the second dose of ivermectin was significantly less than after the initial dose, although it was still significant in the 200-micrograms/kg group. The skin microfilaria counts in the group treated 6-monthly with 150 micrograms/kg was significantly less than in the group treated yearly (12 and 24 months after initial therapy). Prevalence of microfilariae in the anterior chamber and punctate corneal opacities decreased progressively in all groups over 3 years. There appears to be a slight advantage, in terms of antiparasitic effect over the first 2 years, of therapy given 6-monthly compared with yearly.

Grand rounds revisited: results of a survey of U.S. Departments of Medicine

Medical grand rounds is a time-honored weekly conference at United States teaching hospitals. We surveyed 122 departments of medicine to test the hypothesis that grand rounds may have changed with the changing training environment. Our goal was to gain a new perspective on the way physicians learn clinical medicine and maintain their fund of information. A questionnaire was designed to assess several aspects of grand rounds, including format, objectives, popularity, and changes over time. The questionnaire was directed to department heads of 122 U.S. medical schools. Seventy-five percent of respondents were department chairs; the remainder were chief residents and other faculty. Survey response rate was 96%. According to respondents, the major objective of grand rounds was to provide "updates in diagnosis and treatment." Case presentations were regularly included in about one third of departments; patients were rarely present for examination or interview. The popularity of grand rounds was thought to have decreased. These data support the impression that medical grand rounds is still considered important in most academic medical centers. Suggestions are made for increasing the clinical relevance of the conference. New techniques for presenting clinical material are reviewed, and an argument is made for returning to a basic strategy of "solving the patient's problem."

Safety of and compliance with community-based ivermectin therapy

In a study of the safety, acceptability, and efficacy of ivermectin for community-based mass treatment of onchocerciasis, the drug was issued twice, one year apart, to the population of a rubber plantation (14,000 people) in Liberia, where over 80% of the adults have Onchocerca volvulus infection. The plantation microfilarial load in a sample of adults was reduced by 86% 6 months after initial treatment and by 78% after 1 year. Compliance was 97% with each round of treatment. After the initial treatment of 7699 people, 101 (1.3%) had moderate adverse reactions. After re-treatment only 37 (0.5%) people had moderate adverse reactions. No ivermectin-related death or severe adverse reactions occurred. The data show that community-based treatment with ivermectin is well accepted and effective in reducing microfilarial loads. Ivermectin is likely to provide the first realistic means of chemotherapy-based control of onchocerciasis on a mass scale.

Onchocerca volvulus recombinant antigen: physical characterization and clinical correlates with serum reactivity

An Onchocerca volvulus cDNA clone expressing epitopes found in adult and larval parasites, designated lambda RAL-2, was derived from a 1,000-base message present in adult O. volvulus, which encodes a protein with an apparent molecular weight of 17,000. This protein does not appear to be extensively posttranslationally modified. Serum samples from 52 individuals exposed to O. volvulus were examined for antibodies recognizing the lambda RAL-2 recombinant antigen; 77% produced such antibodies. In addition, individuals producing antibodies recognizing the recombinant antigen were significantly less likely to develop some aspects of ocular pathology associated with O. volvulus infection than were individuals who did not do so. These results suggest that recombinant antigens such as that produced by lambda RAL-2 may be useful in attempts to understand the mechanism of O. volvulus-induced ocular pathology.

Effect of single-dose ivermectin therapy on human Onchocerca volvulus infection with onchocercal ocular involvement

Ivermectin has shown promise as a potentially safe and effective microfilaricidal drug for the treatment of onchocerciasis. Several limited studies have shown it to have fewer side effects, especially ocular complications, than the currently available drug, diethylcarbamazine. The detailed ocular findings in 200 moderately to heavily infected Liberians who were enrolled in a safety and dose-finding study are presented. They received either 0, 100, 150, or 200 micrograms/kg of ivermectin and were followed up for 12 months. In clinical studies so far carried out ivermectin in a dose of 100, 150, or 200 micrograms/kg has not been associated with any major adverse reactions nor were there any sight-threatening effects even in the presence of severe ocular disease. Each of these doses significantly reduced the ocular microfilaria load for at least 12 months when compared with either the placebo (p less than 0.05) or pretreatment values (p less than 0.001). However, the 100 and 150 micrograms/kg doses caused fewer minor side effects than the higher dose. These results confirm that ivermectin in a single oral dose may be a safe and effective microfilaricidal drug for the treatment of onchocerciasis and that it appears to be free of major ocular side effects.

Effects of high doses of diethylcarbamazine on adult Onchocerca volvulus examined by the collagenase technique and by histology

Thirty adult male nodule carriers from a hyperendemic onchocerciasis area in the Liberian rain forest were treated with high doses of diethylcarbamazine (30 mg/kg/d) over one week. Another ten patients received placebo tablets and served as a control. All detectable nodules were removed from half of the patients at two months and from the remaining patients at ten months after chemotherapy. The adult worms in the nodules were examined for pathological alterations by the collagenase technique including embryogram, and by histology. No macrofilaricidal effect was observed at either time, and no significant reduction of microfilariae in the uteri of the female worms or in the tissue of the nodules was seen. Two months after the therapy there was a significant increase of degenerated stretched intrauterine microfilariae but this effect was no longer observed after ten months. No pathological effect was seen on the intrauterine coiled microfilariae. On the contrary, their number had significantly increased after ten months which could mean a stimulation of the embryogenesis. No effect on spermatogenesis was observed. Both techniques, the collagenase digestion and the histological examination of the nodules, provided similar results to demonstrate that there was no marked long lasting effect on O. volvulus after a treatment with high doses of diethylcarbamazine.

Histological examination of onchocercomata after therapy with ivermectin

During chemotherapy trials in hyperendemic onchocerciasis areas in West Africa 15 adult nodule carriers in Liberia and 24 patients in Mali received single doses of ivermectin (150 or 200 micrograms/kg). Nodules were extirpated two, six and ten months after therapy and examined histologically. No macrofilaricidal effect of ivermectin was observed. Two months after therapy, in 93% of all female worms with intrauterine stretched microfilariae nearly all microfilariae were degenerated. The percentage was lower after ten months but still significantly higher than in untreated control groups. Ivermectin did not cause degeneration of the intrauterine coiled microfilariae. But the percentage of the female worms with coiled microfilariae was significantly lower two and ten months after therapy than that in the placebo or untreated control groups. Correspondingly, the percentage of nodules with intact microfilariae in the nodule tissue was also significantly lower throughout the examination period than that of the untreated control groups. There was not observed any effect on the spermatogenesis and spermatozoa were found frequently in the uteri of female worms. Using the method of histology, the long lasting inhibitory effect of a single dose of ivermectin on the intrauterine production of microfilariae could clearly be demonstrated. This proves the value of histology for the assessment of drug effects on adult O. volvulus.

Cell-mediated immune responses in human infection with Onchocerca volvulus

Mechanisms involved in modulation of the immune response in persons with chronic Onchocerca volvulus infection are poorly understood. In this study in vitro reactivity of PBMC to O. volvulus antigen (Ovag), streptolysin O (SL-O) and the mitogen PHA was tested in 62 infected individuals (INF), 17 persons living in the endemic area with exposure to the infection, but with no detectable infection (END), and 7 healthy controls (CTRL) in Liberia, West Africa. Mean blastogenic responses to Ovag were minimal and did not differ between the groups. There was, however, heterogenous reactivity to Ovag in the INF and END. For example, individuals with a history of therapy, and half of those less than 17 yr old who were tested, showed high responses. No significant differences in the response to SL-O or PHA were detected between the groups. IL-2 production in response to Ovag was minimal in the majority of infected subjects. Exogenous IL-2 was found to cause a significant increase in mean responses to Ovag and SL-O in INF and END only. Similarly, Ovag did not stimulate IL-1 production in most INF, whereas stimulation with LPS led to significantly greater production of IL-1. Depletion of plastic and nylon wool adherent cells did not increase responses to parasite-related antigen in INF, END or CTRL; however, responses to SL-O were augmented in INF, an effect that was also observed in CTRL. Finally, depletion of CD8 or CD16 cells in INF by C lysis did not increase blastogenic responses. These results indicate that cell-mediated immunity to parasite-related Ag as reflected in lymphocyte responses in vitro is diminished in infected individuals, and that this may be caused by defects in T cell activation.

Cell-mediated immune responses in human infection with Onchocerca volvulus

Mechanisms involved in modulation of the immune response in persons with chronic Onchocerca volvulus infection are poorly understood. In this study in vitro reactivity of PBMC to O. volvulus antigen (Ovag), streptolysin O (SL-O) and the mitogen PHA was tested in 62 infected individuals (INF), 17 persons living in the endemic area with exposure to the infection, but with no detectable infection (END), and 7 healthy controls (CTRL) in Liberia, West Africa. Mean blastogenic responses to Ovag were minimal and did not differ between the groups. There was, however, heterogenous reactivity to Ovag in the INF and END. For example, individuals with a history of therapy, and half of those less than 17 yr old who were tested, showed high responses. No significant differences in the response to SL-O or PHA were detected between the groups. IL-2 production in response to Ovag was minimal in the majority of infected subjects. Exogenous IL-2 was found to cause a significant increase in mean responses to Ovag and SL-O in INF and END only. Similarly, Ovag did not stimulate IL-1 production in most INF, whereas stimulation with LPS led to significantly greater production of IL-1. Depletion of plastic and nylon wool adherent cells did not increase responses to parasite-related antigen in INF, END or CTRL; however, responses to SL-O were augmented in INF, an effect that was also observed in CTRL. Finally, depletion of CD8 or CD16 cells in INF by C lysis did not increase blastogenic responses. These results indicate that cell-mediated immunity to parasite-related Ag as reflected in lymphocyte responses in vitro is diminished in infected individuals, and that this may be caused by defects in T cell activation.

An investigation of age-related factors in the age-job-satisfaction relationship

Most researchers have found a positive linear relation between age and job satisfaction. We attempted to account for this relationship by measuring variables that had been proposed to be causal factors. Subjects were 496 city and county managers working in Florida. Potential explanatory variables were (a) job congruence (the difference between what managers prefer and what they perceive they have in a job), (b) internal-external locus of control, and (c) related demographics-age, salary, organizational tenure, position tenure, and organizational level. Multiple regression analyses found that job congruence and work locus of control accounted for almost all of the variance in the age-satisfaction relationship. This study supports the job change hypothesis, which proposes tha older workers get more of what they want out of work.

Controlled trial and dose-finding study of ivermectin for treatment of onchocerciasis

Ivermectin, given as a single oral dose, has shown considerable promise as a new treatment for onchocerciasis. We assessed the safety and efficacy of ivermectin and tried to determine the optimal dose. Two hundred Liberians received 100, 150, or 200 micrograms of ivermectin/kg or placebo and were followed up for 12 months. Therapy was associated with only minimal systemic and ocular side effects. A 200-micrograms/kg dose was associated with greater systemic reaction than was a 100-micrograms/kg dose. Each treatment group had significant reduction in skin microfilaria counts by day 3 and a decrease of approximately 95% at three months. At three months the proportion of persons with no microfilariae in a specimen of skin was significantly less in the 100-micrograms/kg group than in the 150-micrograms/kg or 200-micrograms/kg groups. At 12 months, the level of microfilariae in skin was still reduced approximately 80%. Significant reduction in ocular involvement was seen in all groups. These results confirm that single-dose ivermectin is effective and well-tolerated and suggest that 150 micrograms of ivermectin/kg may be the optimal dose for initial therapy.

Sensitivity of skin snips in the diagnosis of onchocerciasis

To find the optimum number and combination of skin snips for the diagnosis of onchocerciasis, data of six skin snips (two shoulder, two hip, two calf) taken from 776 Liberians aged 12 to 60 years were examined. From these data, proportions of positive skin snips from the hip, or hip and calf areas, for different levels of skin microfilaria density were calculated. These proportions were used in a mathematical model that examined 20 hypothetical populations with different levels of endemicity and skin microfilaria densities. The sensitivity of using two or four snips was then estimated. If only two snips were taken, two hip snips had the highest sensitivity (ranging from 80.7% to 100% according to the population). When the microfilaria density was high, the addition of two extra snips from the calf did not significantly improve the sensitivity. However, when the microfilaria density was low, the combination of two hip and two calf snips substantially improved the sensitivity (ranging from 80.7% to 94%). If fewer than six skin snips are desired for a particular field study, the choice of how many skin snips to be taken should be based on the expected precision required for that study. This in turn can be determined by skin microfilaria density. If such information is lacking, an estimate can be made from the findings of six snips from a small sample.

Ivermectin effect on microfilariae of Onchocerca volvulus after a single oral dose in humans

Ivermectin is a broad spectrum anti-helminthic agent which is currently being tested for use in human onchocerciasis. Its activity is believed to result from its effect on GABA-mediated neurotransmission. We examined the effects of ivermectin on motility of microfilariae of O. volvulus following administration to humans. When ivermectin was given in dosages of 100, 150 and 200 mcg/kg on day 1 there was a clear reduction in motility of microfilariae obtained on day 3 when compared to microfilariae from the placebo group. The mean motility scores in microfilariae from ivermectin recipients were 3.1, 2.3, and 2.2 at 0, 12, and 24 hours of incubation compared to 3.3, 2.9, and 2.5, respectively, in microfilariae from placebo recipients (p less than 0.003, p less than 0.005, and p less than 0.012, respectively). Examination of the effect according to dose suggested a dose-response relationship. Microfilariae in the anterior chamber of the eye 2 days after a single oral dose of ivermectin showed abnormal and reduced winding and coiling. Microfilariae in 50% of ivermectin recipients showed abnormal motility compared to no such effects in subjects examined concurrently who received oral DEC, DEC lotion or placebo. These observations indicate that ivermectin has an effect on motility of microfilariae of O. volvulus following administration to humans.

An investigation of age-related factors in the age-job-satisfaction relationship

Most researchers have found a positive linear relation between age and job satisfaction. We attempted to account for this relationship by measuring variables that had been proposed to be causal factors. Subjects were 496 city and county managers working in Florida. Potential explanatory variables were (a) job congruence (the difference between what managers prefer and what they perceive they have in a job), (b) internal-external locus of control, and (c) related demographics-age, salary, organizational tenure, position tenure, and organizational level. Multiple regression analyses found that job congruence and work locus of control accounted for almost all of the variance in the age-satisfaction relationship. This study supports the job change hypothesis, which proposes tha older workers get more of what they want out of work.

Treatment of onchocerciasis. The ocular effects of ivermectin and diethylcarbamazine

The ocular changes that occur with diethylcarbamazine treatment of onchocerciasis seriously restrict its usefulness. Ivermectin, a newly developed antifilarial drug, was compared with diethylcarbamazine for treatment of onchocerciasis in a double-masked, placebo-controlled trial. Thirty men with moderate to severe infection and ocular involvement were randomly assigned to receive ivermectin as a single oral dose (200 micrograms/kg), diethylcarbamazine (administered for eight days), or placebo. Detailed ocular examinations were performed serially over a 12-month period. Diethylcarbamazine treatment caused a marked increase in living and dead microfilariae in the cornea, punctate opacities, and limbitis during the first week of therapy. Ivermectin had no such effect. However, ivermectin therapy resulted in a long-term reduction in intraocular microfilariae comparable to that seen with diethylcarbamazine. Ivermectin appears to have few ocular complications and be a better-tolerated and more effective microfilaricidal agent than diethylcarbamazine for the treatment of onchocerciasis.

Comparison of ivermectin and diethylcarbamazine in the treatment of onchocerciasis

We compared ivermectin with diethylcarbamazine for the treatment of onchocerciasis in a double-blind, placebo-controlled trial. Thirty men with moderate to heavy infection and ocular involvement were randomly assigned to receive ivermectin in a single oral dose (200 micrograms per kilogram of body weight), diethylcarbamazine daily for eight days, or placebo. Diethylcarbamazine caused a significantly more severe systemic reaction than ivermectin (P less than 0.001), whereas the reaction to ivermectin did not differ from the reaction to placebo. Diethylcarbamazine markedly increased the number of punctate opacities in the eye (P less than 0.001), as well as the number of dead and living microfilariae in the cornea over the first week of therapy. Ivermectin had no such effect. Both ivermectin and diethylcarbamazine promptly reduced skin microfilaria counts, but only in the ivermectin group did counts remain significantly lower (P less than 0.005) than in the placebo group at the end of six months of observation. Analysis of adult worms isolated from nodules obtained two months after the start of therapy showed no effect of either drug on viability. Ivermectin appears to be a better tolerated, safer, and more effective microfilaricidal agent than diethylcarbamazine for the treatment of onchocerciasis.

Comparison of ivermectin and diethylcarbamazine in the treatment of onchocerciasis

We compared ivermectin with diethylcarbamazine for the treatment of onchocerciasis in a double-blind, placebo-controlled trial. Thirty men with moderate to heavy infection and ocular involvement were randomly assigned to receive ivermectin in a single oral dose (200 micrograms per kilogram of body weight), diethylcarbamazine daily for eight days, or placebo. Diethylcarbamazine caused a significantly more severe systemic reaction than ivermectin (P less than 0.001), whereas the reaction to ivermectin did not differ from the reaction to placebo. Diethylcarbamazine markedly increased the number of punctate opacities in the eye (P less than 0.001), as well as the number of dead and living microfilariae in the cornea over the first week of therapy. Ivermectin had no such effect. Both ivermectin and diethylcarbamazine promptly reduced skin microfilaria counts, but only in the ivermectin group did counts remain significantly lower (P less than 0.005) than in the placebo group at the end of six months of observation. Analysis of adult worms isolated from nodules obtained two months after the start of therapy showed no effect of either drug on viability. Ivermectin appears to be a better tolerated, safer, and more effective microfilaricidal agent than diethylcarbamazine for the treatment of onchocerciasis.

Study on the dehydrating effect of the red cell Na+/K+-pump in nystatin-treated cells with varying Na+ and water contents

Using the antibiotic Nystatin, we have developed a systematic method for the preparation of red blood cells with independently selected levels of intracellular Na+ concentrations and water content. Such cells provided an experimental model to study the effect of Na+/K+ pump stimulation on red cell water content. Even in initially dehydrated cells, stimulation of the Na+/K+ pump by elevated intracellular Na+ caused subsequent further loss of cell water. Cell water loss was reflected in decreased monovalent cation content per unit mass of hemoglobin and by a shift in the density distribution of the cell populations to higher densities on discontinuous Stractan gradients. We conclude that the 3 Na+out : 2 K+in stoichiometry of the Na+/K+ pump results in a net desalting effect with increased pump activity. Under the conditions of these experiments, the cell appears to have no effective mechanism to compensate for a net loss of ions and water.

Sequence organization of cloned intracisternal A particle genes

Seven recombinant DNA clones containing mouse intracisternal A particle genes were isolated and analyzed by restriction enzyme digestion, Southern blot analysis and heteroduplex mapping. The sequence organization of the individual genes was found to differ, with one end of the gene region being most variable, while a central segment of 1.8 kb was missing from two of the clones. A third region, common to all the clones and containing the 3' end of the gene, is present in about 1800 copies per haploid genome, but the central portion is found in only 650 copies. The same reiteration frequency is found in both myeloma tumor and mouse liver DNA. The most abundant intracisternal A particle RNA in two different myeloma lines was found to be 3.5 kb, and RNA/DNA hybrids show that the RNA is homologous to all but a small internal segment of one of the clones.

Morphine-induced behavioral disruption in rats chronically depleted of brain dopamine

The ability of rats, chronically depleted of brain dopamine (DA), to develop tolerance to morphine (120 mg/kg, s.c.) given twice daily was studied using a food-reinforced operant procedure (FR-10). DA was depleted via the administration of 6-OHDA (150 ug, ict.) and desmethylimipramine (DMI; 25 mg/kg, ip.) to rats 14 days of age. This procedure resulted in a 61% depletion of brain DA when these rats were 120 days of age, while norepinephrine levels were not significantly affected. The response rates of DA-depleted and vehicle (ict.) + DMI treated controls were equally suppressed by various acute doses of morphine, but the DA-depleted group appeared to develop tolerance to the higher morphine dosage regimen (120 mg/kg, b.i.d) faster than the control group. In addition, DA-depleted rats exhibited a greater suppression of response rates 24 hr after the cessation of morphine treatment.