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PubMed1991

The effects of repeated administration of MDMA on the expression of sexual behavior in the male rat.

3,4-Methylenedioxymethamphetamine (MDMA, "Ecstasy") is a potent neurotoxin which preferentially produces 5-HT nerve terminal degeneration in the CNS in both rodents and primates. Timely research on the behavioral effects of acute and long term treatment of MDMA is critical due to the neuropathological effects of MDMA and its abuse liability. Presently, there are no published reports that have systematically examined the effects of acute or chronic treatment of MDMA on animal sexual behavior. Accordingly, the effects of repeated systemic administration of MDMA on a variety of parameters of male sexual behavior in sexually vigorous male rats were studied. Treatment consisted of subcutaneous injections of MDMA (40 mg/kg) or saline (1 ml/kg) every 12 hours for 4 consecutive days. In addition, neurochemical assessments of brain 5-HT and 5-HIAA depletion following repeated MDMA treatment were also conducted using reverse phase liquid chromatography. The results of this study revealed that repeated systemic administration of MDMA to sexually vigorous male rats produced a transient disruption of the expression of male copulatory behavior. In addition, in MDMA-treated males that did display copulatory behavior, both the ejaculation latency and postejaculatory interval were dramatically lengthened when compared to saline injected controls. Surprisingly, one week after the first behavioral test, copulatory behavior in MDMA treated rats appeared unaffected despite a marked depletion of 5-HT and 5-HIAA content in the striatum, and hippocampus.

3,4-Methylenedioxyamphetamine↗
PubMed1993

Chronic and acute tolerance to subjective effects of nicotine.

Tolerance to subjective effects of nicotine may induce novice smokers to increase the magnitude and frequency of their nicotine self-dosing. In this study, smokers (n = 8) and nonsmokers (n = 7) participated in three sessions involving presentation of 0, 7.5, or 15 micrograms/kg nicotine 30 min for 2 h via measured-dose nasal spray, with different doses presented on separate days. Subjective responses were assessed using visual analog scales (VASs) of jittery, light-headed, relaxed, dizzy, and head rush, and the Profile of Mood States (POMS) scales of vigor, confusion, fatigue, tension, and the composite scale of arousal. Smaller responses in smokers vs. nonsmokers were viewed as evidence for chronic tolerance. In addition, on each day subjects received a fifth, challenge dose of 30 micrograms/kg 30 min after the previous dosing. Smaller responses to the challenge dose as a function of increasing prior nicotine dosing during Trials 1-4 were viewed as evidence for acute tolerance. Results showed significant changes in most measures as a function of nicotine dose, and the dose-response curves for most VAS and POMS scales tended to be shifted to the right, or dampened, in smokers relative to nonsmokers, consistent with chronic tolerance. However, smokers and nonsmokers tended to respond to nicotine in opposite directions for POMS scales of vigor and arousal, perhaps reflecting withdrawal relief in smokers. Acute tolerance on a few selected VAS and POMS scales was apparent for both smokers and nonsmokers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Behavior of bull spermatozoa in bovine uterine tube epithelial cell co-culture: an in vitro model for studying the cell interactions of reproduction.

Freshly ejaculated bull semen was centrifuged and spermatozoa were resuspended in modified sperm TALP. Bovine uterine tube epithelial cell monolayers (BUTC) were obtained from cows in the periovulatory phase of estrus. In Experiment 1, sperm aliquots were assigned to culture wells containing either BUTC, BUTC-conditioned TALP, or control TALP. Sperm heads attached to the monolayers within 1 h of co-culture. Attached spermatozoa showed vigorous tail motion. At 5, 8 and 11 h of incubation at 39 degrees C, the percentage of unattached sperm cells with intact acrosome membranes and percentage of motility of these cells was measured. Sperm-BUTC co-cultures were also fixed in situ for electron microscopy. Unattached spermatozoa in co-culture had more (P<0.05) acrosomal membrane loss, showed hyperactive motion and had an overall decrease in motility as compared to sperm cells in control or conditioned medium. Evaluation by electron microscopy showed BUTC attached spermatozoa to behave in the co-culture system similar to reports for spermatozoa found in uterine tubes in vivo. Microvilli of the BUTC appeared to actively entrap the spermatozoa. Mucus-type granules could be seen on acrosomal regions and vesiculation of acrosomal membranes was seen in some cells. In Experiment 2, 43% of the 12 x 10(6) sperm cells added to 2-cm(2) BUTC bound within 4 h of co-culture. By 7 h of co-culture 19% of the previously bound sperm cells had been released from the BUTC. Released cells had limited motility and were mostly dead (73%). Sperm cells remaining on the monolayer at 7 h showed vigorous tail motion and were gradually released from the BUTC over 48 h. Spermatozoa in co-culture interacted with the BUTC in a manner much like that seen in vivo, and sperm capacitation changes were stimulated by this interaction.

Journal Article↗
PubMed1991

Physical activity and incidence of non-insulin-dependent diabetes mellitus in women.

The potential role of physical activity in the primary prevention of non-insulin-dependent diabetes mellitus (NIDDM) is largely unknown. We examined the association between regular vigorous exercise and the subsequent incidence of NIDDM in a prospective cohort of 87,253 US women aged 34-59 years and free of diagnosed diabetes, cardiovascular disease, and cancer in 1980. During 8 years of follow-up, we confirmed 1303 cases of NIDDM. Women who engaged in vigorous exercise at least once per week had an age-adjusted relative risk (RR) of NIDDM of 0.67 (p less than 0.0001) compared with women who did not exercise weekly. After adjustment for body-mass index, the reduction in risk was attenuated but remained statistically significant (RR = 0.84, p = 0.005). When analysis was restricted to the first 2 years after ascertainment of physical activity level and to symptomatic NIDDM as the outcome, age-adjusted RR of those who exercised was 0.5, and age and body-mass index adjusted RR was 0.69. Among women who exercised at least once per week, there was no clear dose-response gradient according to frequency of exercise. Family history of diabetes did not modify the effect of exercise, and risk reduction with exercise was evident among both obese and nonobese women. Multivariate adjustments for age, body-mass index, family history of diabetes, and other variables did not alter the reduced risk found with exercise. Our results indicate that physical activity may be a promising approach to the primary prevention of NIDDM.

Adult↗
PubMed1985

A simple method for increased recovery of purified paramyxovirus virions.

A simple method involving vigorous agitation of infected cell monolayers prior to collection of culture medium is described to greatly increase the recovery of purified virions of measles virus, respiratory syncytial virus and human parainfluenza virus. Vigorous agitation of the flasks containing monolayers of infected cells increased the recovery of purified virions by at least 3- to 10-fold as judged by the intensity of [35S]methionine labeled viral proteins on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). These protein profiles also indicated that these virions were as clean as those purified from gently collected medium. Analysis of titers of infectious virus recovered from medium of agitated and non-agitated flasks showed similar increases. These results suggest that the cell associated nature of these viruses may be at least partly due to either partially budded virions or mature virions sticking to the cell membrane, since these both might be expected to be freed from the cell by mechanical shearing.

Animals↗
PubMed1995

High efficiency induction of papillomas in vivo using recombinant cottontail rabbit papillomavirus DNA.

Plasmids containing cottontail rabbit papillomavirus (CRPV) DNA can induce papillomas in vivo, but efficiency has been low. The aim of the present investigation was to explore some of the technical variables involved in inoculation of rabbits with recombinant CRPV DNA in attempts to improve both yield and consistency of papilloma induction. It was found that induction of epidermal hyperplasia, with either a mixture of turpentine and acetone or phorbol esters, produced a marked increase in papilloma yield. An additional powerful factor was the use of very vigorous, cutaneous scarification, sufficient to penetrate the papillary dermis and produce bleeding. When used in combination, papilloma yields were consistent and often reached 90-100% of inoculated sites. A number of other variables which did not consistently affect papilloma yield were tested. These included bleb and puncture injections, plasmid dose, vector type, occlusive dressings, lipofection reagent, carrier DNA, and different methods for plasmid DNA extraction and purification. It is concluded that the most important variables in improving papilloma yields were prior induction of epidermal hyperplasia and vigorous cutaneous scarification.

Acetone↗
PubMedDate not supplied

Activity of primate magnocellular red nucleus related to hand and finger movements.

Single cells were recorded in the magnocellular red nucleus (RNm) of two cynomolgus monkeys using tungsten microelectrodes. The first monkey was trained to press finger switches and to operate a push-pull device. Comparison of responses while operating the two devices demonstrated a strong distal bias. The finger device elicited large modulations in discharge (greater than or equal to 50 impulses/s) in 75% of the sampled neurons. Most cells fired optimally during thumb switch operation, but also fired vigorously in association with other switch operations. The left motor cortex was removed from the second monkey 18 months prior to microelectrode recording. Cells in the cortically denervated RNm discharged vigorously in association with grouped finger movements that opened and closed the affected right hand. These results coupled with our previous findings suggest that the RNm is preferentially linked to distal limb muscles, and the primary role of the forelimb zone may be to control coordinated hand function including grouped movements of the fingers.

Animals↗
PubMed1990

Nigral D1 and striatal D2 receptors mediate the behavioral effects of dopamine agonists.

The mediation of behavior by nigral and striatal dopamine (DA) D1 and D2 receptors was investigated in rats that had sustained extensive unilateral 6-hydroxydopamine-induced injury to ascending DA neurons. Selective D1 and D2 agonists and antagonists were injected directly into the DA-denervated substantia nigra pars reticula or the caudate-putamen via a chronically indwelling cannula. Contralateral rotation resulting from unilateral stimulation of supersensitive DA receptors was quantified over 46 min. Intrastriatal apomorphine (5 micrograms) or the selective D2 agonist quinpirole (5 micrograms), but not the selective D1 agonist (+/-)-SKF 38393 (15 micrograms), induced vigorous rotation. The rotation induced by intrastriatal quinpirole was greatly diminished by systemic administration of the selective D2 antagonist eticlopride (0.5 mg/kg, i.p.) and could not be enhanced by additional injection of intrastriatal (+/-)-SKF 38393. Intranigral administration of apomorphine or (+/-)-SKF 38393, but not quinpirole (same doses as above), elicited vigorous rotation. However, the rotation induced by intranigral (+/-)-SKF 38393 could not be blocked by systemic administration of the selective D1 antagonist SCH 23390 (0.5 mg/kg, s.c.), and was mimicked by intranigral (-)-SKF 38393 (15 micrograms), which exhibits 100-fold less activity than the dextrorotatory enantiomer at the D1 receptor. In order to circumvent the problem of this drug's apparent non-D1-mediated action when injected intranigrally, rotation was induced by systemic (+/-)-SKF 38393 (2.0 mg/kg, i.p.) 10 min after intranigral administration of selective antagonists. Intranigral SCH 23390 (10 micrograms), but not eticlopride (10 micrograms), powerfully antagonized the rotation induced by systemic (+/-)-SKF 38393. Conversely, rotation induced by systemic quinpirole (0.5 mg/kg, i.p.) was potently blocked by intrastriatal eticlopride but not SCH 23390. Rotation induced by systemic apomorphine (0.25 mg/kg, i.p.) was not attenuated by either antagonist alone, regardless of intracerebral injection site. The results indicate that both nigral D1 and striatal D2 receptors mediate the behavioral effects of DA agonists. These data may be useful in elucidating the mechanism(s) underlying the D1/D2 synergism observed in neurologically intact animals, as well as in understanding the action of drugs used in the treatment of Parkinson's disease.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1991

The influence of parasites on host sexual selection.

In 1982 Hamilton and Zuk(1) proposed a provocative solution for the unexplained fact that the males of many species exhibit 'showy' traits such as brightly coloured plumage or vigorous courtship displays. They suggested that showy traits are fully expressed only by males who are resistant to parasites and that females examine such traits in order to choose resistant males as mates. Hamilton and Zuk's proposal has been the topic of extensive research and vigorous debate for nearly a decade. This article reviews the research, relevant criticisms and unanswered questions pertaining to the influence of parasites on sexual selection.

Journal Article↗
PubMed1992

Perspectives: bone's mechanical usage windows.

As mechanical usage (MU) of a bone changes from complete disuse towards maximal vigor, the biologic mechanisms that can adapt it to its MU tend to react predictably. Acute disuse can increase BMU (Basic Multicellular Unit, the remodeling 'packet') creations but reduces how much bone they form, to increase bone loss next to marrow. Normal usage reduces those creations to normal and tends to equalize their resorption and formation; this conserves bone. In mild overloading, BMUs still conserve existing bone, while modeling drifts can begin adding to and/or reshaping it. Severe overloading can increase microdamage alarmingly, its repair by BMUs too, and can cause woven bone formation, anarchic resorption and a regional acceleratory phenomenon. Those ranges of MU vigor can define four 'windows'. An adapted window should apply to healthy, normally active adult mammals, and a mild overload window to healthy, normally active growing ammals. The biologic responses in the pathologic window could explain among other things some total joint and internal fixation failures, some pathologic fractures and some bone healing and sports medicine problems.

Adaptation, Physiological↗
PubMed1992

Nutrition and cellular immunity.

We have investigated the influence of nutrition on immune function in animals and man over the past two decades. The profound impairment of immune function that had not been observed in children in developing countries could not consistently be reproduced in the laboratory setting; paradoxically, moderate nutritional restriction could even enhance T-cell-based cell-mediated immune responses in experimental animals. Studies of the crucial role of the element zinc in maintenance of vigorous cellular immunity provided at least a partial explanation of this paradox. Zinc, shown to be absolutely crucial for development and expression of both T- and B-cell functions, was commonly deficient as were other micronutrients under many conditions of protein-calorie malnutrition. Indeed, administration of adequate zinc alone could correct some of the T-cell-mediated immune functions in children with protein-calorie malnutrition. In later investigations we found that as long as all essential nutrients were supplied in adequate amounts, 40% chronic energy (calorie) restriction will regularly extend lifespan and maintain vigorous immunologic function while preventing numerous cancers and immunologically based diseases of aging, such as profound and destructive autoimmune diseases in genetically short-lived mice strains, as it was known to do for moderately long-lived rats and long-lived strains of mice. Such undernutrition without malnutrition appears to influence a wide range of critical metabolic and physiologic processes in both short-lived and long-lived animals. One of the most challenging of these influences was a down-regulation of cellular proliferation and cell turnover in each of the rapidly replicating tissues studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Development of countermeasures for medical problems encountered in space flight.

By the turn of this century, long-duration space missions, either in low Earth orbit or for got early planetary missions, will become commonplace. From the physiological standpoint, exposure to the weightless environment results in changes in body function, some of which are adaptive in nature and some of which can be life threatening. Important issues such as environmental health, radiation protection, physical deconditioning, and bone and muscle loss are of concern to life scientists and mission designers. Physical conditioning techniques such as exercise are not sufficient to protect future space travellers. A review of past experience with piloted missions has shown that gradual breakdown in bone and muscle tissue, together with fluid losses, despite a vigorous exercise regimen can ultimately lead to increased evidence of renal stones, musculoskeletal injuries, and bone fractures. Biological effects of radiation can, over long periods of time increase the risk of cancer development. Today, a vigorous program of study on the means to provide a complex exercise regimen to the antigravity muscles and skeleton is under study. Additional evaluation of artificial gravity as a mechanism to counteract bone and muscle deconditioning and cardiovascular asthenia is under study. New radiation methods are being developed. This paper will deal with the results of these studies.

Aerospace Medicine↗
PubMed1987

Effects of increased energy expenditure on weight gain and adiposity in the LA-corpulent rat.

Groups of lean or pre-obese LA/N-cp rats were subjected to a program of vigorous exercise (less than 4 hr/day) or remained sedentary from 6 weeks until 12 weeks of age. Sedentary pre-obese rats gained weight twice as rapidly as sedentary lean rats. Exercise treatment resulted in greater decrements in body wt in obese than in lean rats, but did not result in absolute weight loss in either group. At 12 weeks of age, fat pad weights in principle depots were 10-15 times greater in corpulent than in lean rats and were significantly smaller in the exercised groups of both phenotypes, and corresponded with lower relative adiposity compared to corresponding sedentary groups. Heart weights were greater in corpulent than lean, while gastrocnemius muscle weights were similar in both phenotypes. Exercise was without effect on the weight of either muscle tissue in either phenotype. Interscapular brown adipose tissue weights and the IBAT:BW ratio were greater in obese than in lean rats. IBAT weights were lower in exercised than sedentary rats of either phenotype, but the IBAT:BW ratio was lower only in the obese exercised rats. In sedentary rats, L-alpha-glycerophosphate dehydrogenase and malic enzyme activity were greater in obese than lean, and exercise treatment resulted in increased L-alpha-glycerophosphate dehydrogenase and malic enzyme only in lean rats. These results are consistent with a redistribution of energy expenditure from energy storing to energy dissipating pathways following vigorous exercise, resulting in slowed rates of weight gain and body fat accretion in both lean and obese animals, with the most significant decrements among pre-obese rats.

Adipose Tissue↗
PubMed1989

The effects of smoking on the mood, cardiovascular and adrenergic reactivity of heavy and light smokers in a non-stressful environment.

Following a period of overnight deprivation, 58 smokers participated in a 90-min laboratory assessment in which they viewed a non-stressful movie and smoked two 0.5-mg nicotine-containing cigarettes. The first cigarette was given to all subjects following 25 min of adaptation and baseline. The next cigarette was provided at their request, which occurred 9-12 min later. "Heavy" and "light" smokers were grouped according to their average morning cotinine values, which fell above or below 250 ng/ml, respectively. The results showed that, relative to their baseline, heavy and light smokers experienced about the same level of post-smoking change in blood nicotine, heart rate and blood pressure. However, heavy smokers showed a significantly greater delta from baseline in post-smoking measures of epinephrine, norepinephrine, tension reduction and increase in vigor enhancement. A strong and consistent correlation was observed between post-smoking increases in epinephrine, tension reduction and increased vigor.

Adult↗
PubMed1992

Neurotoxic damage evokes regenerative responses from adult rat sensory neurones.

When adult rats were pre-treated systemically with the excitotoxin, capsaicin, a subset of their dorsal root ganglion (DRG) sensory neurones responded as if they had been axotomised. Firstly, an increased proportion of capsaicin-sensitive DRG neurones (identified by using a cobalt stain) vigorously extended processes in vitro. Additionally, a subset of small dorsal root ganglion neurones expressed elevated levels of the growth-associated protein-43 (GAP-43) in situ. Both vigorous neuritogenesis and elevated GAP-43 levels are characteristics of neurones that are actively regenerating following mechanical damage. Although capsaicin-treated adult DRG neurones show these regenerative responses, their C-fibers fail to regenerate in vivo.

Animals↗
PubMed1987

A prospective analysis of stress and fatigue in recurrent low back pain.

The purpose of the present study was to determine whether patients with recurrent low back pain display a different pattern of mood fluctuations across days than matched healthy controls and whether these mood states are related to pain occurrence and/or magnitude using a prospective design. The questions addressed are whether mood states prior to a pain episode are associated with the episode or whether mood relates to pain as a secondary reaction. Similarly, the relationship between mood state recorded prior to, during or following pain and magnitude of pain experienced was investigated. Thirty-three ambulatory chronic low back pain patients and an equivalent group of asymptomatic controls matched for age, sex, socioeconomic status, and reported activity level monitored mood state (anxiety, tension, depression, anger, vigor, fatigue, confusion) and pain before breakfast, at 4 p.m. and at bedtime for 14 consecutive days. Groups were successfully matched. Analyses revealed significantly higher levels of tension, anxiety and fatigue and lower levels of vigor in the pain cases. No mood state was predictive of pain onset but fatigue was associated with pain 24 h following pain, indicating fatigue as secondary to pain. While mood state recorded prior to or following pain was unable to predict magnitude of pain, fatigue was associated with the level of pain experienced during the pain episode itself. The findings reveal a pattern of anxiety, tension and fatigue where fatigue is associated with increased pain during the pain episode and is increased 24 h following pain. This fatigue-pain relationship is superimposed upon a continuous elevation of anxiety and tension. These findings suggest the importance of pain management efforts directed at decreasing patients' fatigue levels, and increasing functional endurance while simultaneously reducing anxiety. The results also question the role of negative mood states in the initiation or exacerbation of pain and highlights the influence of physical mood states such as fatigue on pain in low back pain.

Adult↗
PubMed1996

Vasodilatation and enhanced oxidative metabolism of the cerebral cortex provoked by the periaqueductal gray matter in anaesthetized rats.

The aim of the present study was to evaluate the possible contribution of the cerebral cortical oxidative metabolism to the cortical vasodilator action of the periaqueductal gray. In 70 rats with cervical cordotomy, we found that unilateral stimulation of the caudal third of the lateral longitudinal column of the periaqueductal gray with N-methyl-D-aspartate bilaterally provoked the greatest increase in cortical blood flow (laser-Doppler flowmetry and/or microsphere flowmetry). The response was widespread over the entire neocortical regions, elicited in a dose-dependent manner, with little change in arterial blood pressure. The flow was increased effectively by a submaximal dose of the amino acid (1 mM, 100 nl), attaining a peak increase by 99 +/- 41% of the baseline level (mean +/- S.D., n = 30), and was associated with an enhancement of the cortical metabolic rate for oxygen by 51 +/- 26%. We then compared the flow increase with that induced by cold exposure (by 52 +/- 29%, n = 27), the latter response being tightly coupled to an enhanced metabolic rate for oxygen (by 41 +/- 23%). It was thus found that the increase in cortical blood flow provoked by the subdivision was dependent on the cerebrovasodilator mechanism that may be coupled to the cortical oxidative metabolism to the extent of one-half, and on certain other mechanisms for the remaining half. In view of the fact that this particular region serves to generate vigorous defence reactions that involve flight behaviour, the region should also help to meet the urgent demand for an increased cortical blood flow, so as to prepare for the possible generation of cortical hyperactivity in coping vigorously with a threatening emergency.

Anesthesia↗
PubMed1995

Effect of pleasant odors on mood of males at midlife: comparison of African-American and European-American men.

The purpose of this study was to determine if daily use of colognes could elevate mood in middle-aged men. Sixty men ranging in age from 40 to 55 years participated in the study. Half were European-American and half were African-American. Mood ratings were obtained twice daily for 12 days using the Profile of Mood States questionnaire (POMS). The first 2 days of the experiment were used as baseline information to establish each man's mood prior to the administration of the colognes. The following 10 days of the study consisted of two conditions of 5 days each, the fragrance condition and the placebo condition. Main effects of condition (baseline, fragrance, placebo) were found for all POMS factors including tension, depression, anger, vigor, fatigue, and confusion, as well as for the Total Mood Disturbance score (TMD). The scores for the fragrance condition were significantly better than those for the baseline condition for tension, depression, anger, fatigue, and confusion factors, as well as for the TMD. Also, the scores for the fragrance condition were significantly better than those for the placebo condition for all factors and the TMD. There was a main effect for race, with European-American subjects having significantly worse scores for tension and fatigue and significantly better scores for depression than African-American subjects. An interaction was present between race and condition for the depression, vigor, and confusion factors. The main conclusion of this study was that use of pleasant odors improved the mood of males at midlife.

Adult↗