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To examine interactions between alcohol and endogenous opioids in their suppressive effects on rat testicular function, the opioid antagonist naltrexone or the opioid agonist morphine was administered to adult male rats alone or in combination with alcohol. Serum testosterone, testicular interstitial fluid (TIF) testosterone, and TIF volumes were measured to assess testicular function. Naltrexone induced dose-dependent increases in serum and TIF testosterone levels without changes in TIF volume. Alcohol (0.5 g/kg) inhibited naltrexone-induced stimulation of testosterone secretion and shifted the naltrexone dose-response curve to the right. Conversely, naltrexone (0.05 mg/kg) inhibited alcohol-induced suppression of testosterone secretion and shifted the alcohol dose-response curve to the right. Relatively high doses of naltrexone (5 to 30 mg/kg) were needed to stimulate testosterone secretion maximally in rats treated with a low dose of alcohol (0.5 g/kg) and to stimulate normal levels of testosterone secretion in rats treated with a high dose of alcohol (2 g/kg). In addition, combined treatment with 1 and 30 mg/kg of naltrexone and 0.5 to 2 g/kg of alcohol did not alter blood alcohol concentrations significantly, suggesting that the interactions between alcohol and naltrexone were unrelated to gross changes in alcohol metabolism or bioavailability factors. Simultaneous treatments with a low dose of alcohol (0.3 g/kg), near the threshold of efficacy, and low-moderate doses of morphine (0.3 to 3 mg/kg) were not additive in suppressing testosterone secretion, compared with either agent alone. These results support the hypothesis that opioid antagonists can reverse the suppressive effect of alcohol on testicular steroidogenesis, but the results also suggest that endogenous opioids do not exclusively mediate alcohol's effects on testosterone secretion.

In order to analyze sunbathing practices, a survey was conducted during the summer of 1995 on three Connecticut state beaches, with 1,003 interviews completed. The majority (65.8%) of respondents were women. Almost 70% of respondents were visiting the beach to get or maintain a tan. While the intended beach stay averaged four hours, only 55.7% of respondents were using sunscreen, 6.9% were sitting under shade, 12.7% were wearing hats, and 17.1% were wearing clothes other than a bathing suit. More than half (55%) of the sunscreen used had a sun protection factor of less than 15. Children were provided with greater protection than adults. The survey indicates the need for greater educational efforts to motivate protective behavior. Primary-care physicians could have an important role in these efforts.

Patients infected with human immunodeficiency virus (HIV) have a high prevalence of UV radiation-responsive skin diseases including psoriasis, pruritus, eosinophilic folliculitis and eczemas. On the other hand, UV has been shown to suppress T cell-mediated immune responses and to induce activation and replication of HIV. These developments have prompted clinicians and investigators to question whether phototherapy is safe for HIV-infected individuals. We have reviewed these issues and hereby provide a summary and critique of relevant laboratory and clinical evidence.

These studies examined whether nitric oxide (NO) mediates opioid suppression of testicular steroidogenesis. Adult male rats were treated with various combinations of a NO synthase (NOS) inhibitor (NG-nitro-L-arginine methyl ester; NAME), a NO donor (isosorbide dinitrate; ISDN), an opioid agonist (morphine, and an opioid antagonist (naltrexone). Serum LH and testosterone and testicular interstitial fluid (TIF) testosterone concentrations were then measured. Inhibition of NO production by NAME reversed morphine-suppressed testosterone secretion; treatment with the NO donor, ISDN, reversed naltrexone-stimulated testosterone secretion. NAME did not alter morphine's effects on LH secretion and attenuated morphine's suppression of hCG-stimulated testosterone secretion, indicating that these effects occur directly in the testes and are not dependent on LH secretion. Even though these effects suggested possible interactions between NO and opioid systems, no additive or synergistic effects were found with suppressive combinations of morphine and ISDN, or with stimulatory combinations of naltrexone and NAME at does that had little effect on testosterone secretion when given alone. These results indicate that opioid and NO exert independent effects on testicular steroidogenesis through separate pathways or mechanisms and that NO does not mediate opioid-induced testicular suppression.

Although 5 years old, the Americans with Disabilities Act of 1990 is still considered a relatively new law. Physicians' practices are influenced daily by the Act--from office hiring practices to treating disabled patients. This article is in response to several questions that have been raised concerning the scope of the Act as it applies to a physician's office when treating hearing impaired patients.

Evidence has been reported supporting the hypothesis that nitric oxide (NO) partially mediates the expression of morphine dependence. To examine whether NO-related agents also affect the expression of alcohol dependence, adult male rats were treated chronically with alcohol. Upon withdrawal of alcohol administration, abstinence signs were observed after treatment with a NO synthase (NOS) inhibitor, NG-nitro-L-arginine methyl ester (NAME), or a NO donor, isosorbide dinitrate (ISDN). Withdrawal severity was based primarily on the presence and intensity of tremors, rigidity, hyperactivity, and spontaneous and audiogenic convulsions. The NOS inhibitor, NAME (10-100 mg/kg), injected during alcohol withdrawal significantly inhibited withdrawal severity decreasing the intensity of signs of hyperactivity, tremors, and rigidity, but not affecting the occurrence of convulsions. The NO donor, ISDN (30 mg/kg), administered during alcohol withdrawal significantly increased the severity of most withdrawal signs. These results suggest that NO mediates some aspects of the expression of alcohol dependence.

To examine whether nitric oxide (NO) affects alcohol (ethanol) narcosis, adult male rats were pretreated with a NO synthase (NOS) inhibitor, NG-nitro-l-arginine methyl ester (NAME); a NOS substrate, l-arginine methyl ester (AME); or a NO donor, isosorbide dinitrate (ISDN); then treated with anesthetic doses (3-5 g/kg, ip) of alcohol. Pretreatment with NAME (30-100 mg/kg, sc) 40 min before alcohol treatment delayed the onset of alcohol-induced loss of the righting reflex (LORR) and increased the duration of the LORR. NAME (100 mg/kg) pretreatment combined with high doses of alcohol (4-5 g/kg) exerted significant lethal effects, even though treatment with either agent alone or NAME combined with lower doses of alcohol (3-3.5 g/kg) was not lethal. Simultaneous treatment with the NOS substrate AME (100 mg/kg, subcutaneous) blocked the effects of NAME on LORR duration times, but did not alter LORR onset times. The NO donor ISDN (30 mg/kg) given by oral gavage 2 hr before alcohol decreased LORR duration times without affecting the onset of LORR. In addition, ISDN dose-dependently inhibited NAME-induced LORR duration increases during alcohol narcosis without significantly altering LORR onset times. Neither ISDN nor NAME significantly altered blood alcohol concentrations. These results suggest that NOS inhibition and subsequent decreases in NO production enhance alcohol-induced narcosis and that increases in NO concentrations inhibit alcohol narcosis, supporting the hypothesis that inhibition of arginine-NOS-NO systems mediates part of the sedative-hypnotic effect of alcohol.

Estimates of the smoking-attributable morbidity, mortality, and economic costs for Connecticut for 1989 were made using software distributed by the Centers for Disease Control and Prevention. The software calculations are based on relative risks for smoking-related diseases from major prospective studies. Using smoking prevalence, mortality, population, and health-care expenditure data for the state, 19.3% of all deaths in Connecticut in 1989 were estimated to be related to smoking. Cardiovascular disease and cancer accounted for the largest number of these estimated deaths. Men who died from smoking-related deaths lost an estimated 11.6 years of life while women died an estimated 12.8 years prematurely from smoking-related causes. The total cost, including direct and indirect smoking-related costs, was estimated to be $944 million, or $287 for each man, woman, and child in the state.

All cases of occupational carpal tunnel syndrome (OCTS) who received surgery for this condition in the Washington State workers' compensation system were identified using claim and physician billing databases. One hundred ninety-one incident surgical cases were identified between July 1, 1987 and December 31, 1987, and were followed up a mean of 3 years postoperatively for clinical, disability, and return to work outcomes. Medical record and claim file review was required for clinical and employment information. The mean age of all patients was 36.6 years, 48% were female, and 40% received bilateral surgery. The mean time from claim filing to surgery was 187 days. Ninety-eight percent of cases met the National Institute for Occupational Safety and Health (NIOSH) case definition for OCTS. Relief of pain was complete or modest in 86% (124/145) and only 14% of cases reported no improvement in symptoms. Mean duration of disability (time loss) postoperatively was nearly 4 months, and 8% of cases exceeded 1 year of time loss. The majority of cases returned to their same job (67%) or to a different job (15%). Workers in high risk occupations were less likely to return to the same job after CTS surgery compared to those in lower risk occupations (61% vs. 75%, p = 0.08). In this population, no association was seen between any outcome and age, gender, marital status, or baseline wage. Duration of disability was not significantly related to preoperative severity of OCTS or to more specific case criteria for this condition.(ABSTRACT TRUNCATED AT 250 WORDS)

An acute injection of an intoxicating dose of alcohol to male rats 24 hours prior to breeding with drug-naive females produced no discernible effect on copulatory activity, as reflected in vaginal plugs, but resulted in markedly (> 50%) reduced pregnancy rates. Fetal outcome was also markedly affected in offspring sired by alcohol-treated males: litter sizes were appreciably smaller (30%) and fetal mortality was more than 2 times higher than in controls. These results suggest that paternal alcohol use, like maternal alcohol abuse, may adversely affect fertility and fetal outcome.

To examine whether nitric oxide (NO) mediates the suppression of testosterone secretion by alcohol (ethanol), adult male rats were pretreated with a NO synthase inhibitor, NG-nitro-L-arginine methyl ester (NAME), then treated with alcohol. Serum and testicular interstitial fluid (TIF) testosterone concentrations, serum luteinizing hormone (LH) concentrations, blood alcohol concentrations (BAC), and TIF volumes were measured 2 hr after alcohol treatment at a time of peak effects of alcohol and NAME on testosterone secretion. Pretreatment with NAME (30 or 100 mg/kg, subcutaneous) 30 min before alcohol treatment (0.5-3 g/kg, intraperitoneal) completely blocked the alcohol-induced suppression of testosterone secretion into the general circulation and into TIF without significantly altering blood alcohol concentrations (BAC) or TIF volumes. These results support the hypotheses that NO synthase inhibitors can antagonize alcohol-induced suppression of testicular steroidogenesis, that alcohol interacts with arginine-NO synthase systems that regulate testicular steroidogenesis, and that NO is involved in mediating alcohol's testicular and reproductive effects.

Objective: In the United States, 20% or more of nursing home residents receive antipsychotic drugs, primarily for the behavioral manifestations of dementia. This high level of use of drugs with substantial toxicity has engendered a strong and persistent controversy and recently has led to explicit regulatory measures to curtail use (Omnibus Budget Reconciliation Act of 1987). We developed and tested a comprehensive program to reduce antipsychotic use through education of physicians, nurses, and other nursing home staff. The primary elements of the program were instruction in use of behavioral techniques to manage behavior problems and encouragement of a trial of gradual antipsychotic withdrawal., Design: In a nonrandomized controlled trial, the program was implemented (beginning in August 1990) in two rural Tennessee community nursing homes with elevated antipsychotic use; two other comparable homes were selected as concurrent controls., Patients: Throughout the study 194 residents were in the education homes and 184 were in the control homes. Residents in both groups of homes had comparable demographic characteristics and functional status, and each group had a baseline rate of 29 days of antipsychotic use per 100 days of nursing home residence., Main Outcome Measures: The primary end points were postintervention changes in administration of antipsychotics and other psychotropic drugs, use of physical restraints, and frequency of behavior problems., Results: Days of antipsychotic use decreased by 72% in the education homes vs 13% in the control homes (P < .001). No significant changes were noted in the use of other psychotropic drugs in either group. Days of physical restraint use decreased 36% in the education homes vs 5% in the control homes (P < .001). Behavior problem frequency did not increase in either group, even among the 48% of baseline antipsychotic users in the education homes who had antipsychotic drug regimens discontinued for 3 or more months., Conclusions: The educational program led to a substantial reduction in antipsychotic use with no increase in the frequency of behavior problems. This suggests that for many antipsychotic drug users benefits may be marginal and that programs to reduce such drug use among the 250,000 US nursing home residents receiving these drugs should have high priority.

The hypothesis that an arginine-nitric oxide (NO) synthase-NO system mediates the morphine abstinence syndrome was tested in adult male rats implanted subcutaneously for 3 days with one morphine (75 mg) pellet followed by naloxone-precipitated withdrawal (0.5 mg/kg). Injection with a NO synthase inhibitor, NG-nitro-L-arginine methyl ester (NAME, 100 mg/kg subcutaneous), shortly before naloxone-induced withdrawal significantly inhibited abstinence signs by 25-80%. Continuous infusion of NAME via subcutaneous osmotic pumps during the development of morphine physical dependence and during naloxone-precipitated withdrawal also inhibited morphine abstinence signs. In addition, treatment with isosorbide dinitrate, a NO donor, induced a quasi morphine-abstinence syndrome (QMAS) that was significantly suppressed by implantation of a morphine pellet 3 days before isosorbide dinitrate treatment. These results indicate that NO mediates part of the expression of the morphine abstinence syndrome.

Study of non-hip fractures, which are a serious public health problem for persons greater than or equal to 65 years of age, has been hindered by the absence of an economical method for case identification. We assessed the utility of computerized Medicare inpatient, emergency room, hospital outpatient department and physician claims for identifying fractures in an elderly Tennessee Medicaid population. We used these files for 1987 to identify 3086 possible fractures and reviewed medical records for a sample of 1440. Using this sample, we developed a definition of probable fractures that excluded claims unlikely to represent newly diagnosed fractures. For all fractures, this definition had a positive predictive value of 94%, which for individual fracture sites, ranged from 79% (tibia/fibula) to 98% (hip). Of fractures in the reviewed sample, 91% were identified as probable fractures; this upper bound for sensitivity varied between 75% (femoral shaft) and 100% (patella). These data suggest that computerized Medicare files can be used for rapid and economical fracture ascertainment among persons greater than or equal to 65 years of age. However, further work is needed to obtain better estimates of sensitivity.

Recent studies suggest that nitric oxide (NO) may regulate hormone biosynthesis and secretion. This was tested by treating male rats with NG-nitro-L-arginine methyl ester (NAME), a NO synthase inhibitor, and measuring serum and testicular interstitial fluid testosterone and serum corticosterone, luteinizing hormone (LH), and prolactin (PRL). The effect of NG-nitro-L-arginine (NA), a less-soluble form of the same NO synthase inhibitor, on the reproductive suppressant actions of alcohol was also examined. NAME increased testosterone and corticosterone secretion dose-dependently without affecting LH and PRL secretion. The alcohol-induced suppression of testosterone or LH secretion was not altered by treatment with NA. Although effects of NAME and NA on other systems may be involved, these results indicate that testicular and adrenal steroidogenesis are negatively regulated by endogenous NO and that NO does not regulate LH and PRL secretion or inhibit the testicular steroidogenic pathway in the same way as alcohol.

In an attempt to examine the relationship between alcohol-induced alterations in immunoreactive beta-endorphin (i-beta E) levels in the hypothalamic-pituitary-gonadal axis and the synthesis and release of reproductive hormones, male rats were treated with either an acute intraperitoneal injection of alcohol or were chronically exposed to an alcohol-containing liquid diet. Hypothalamic, pituitary, serum, and testicular levels of immunoreactive beta-endorphin (i-beta E) and serum levels of luteinizing hormone (LH) and testosterone were measured at various times after initiation of these treatments. Testicular interstitial fluid (TIF) volumes and levels of TIF i-beta E and testosterone were also measured 4 hr after acute treatment as an index of testicular release of these substances. Acute alcohol decreased pituitary levels of i-beta E and increased serum levels of the peptide for up to 1 hr after its injection, but did not alter hypothalamic or testicular levels. Acute alcohol markedly increased TIF i-beta E and decreased TIF testosterone and TIF volume. Sharp decreases in serum LH and testosterone were observed in association with these acute changes in i-beta E levels in the pituitary, blood, and testes. During chronic alcohol exposure serum testosterone levels were substantially depressed, but tolerance appeared to develop quickly to the chronic effects of alcohol on serum LH. Similarly, tolerance to alcohol's effects on i-beta E levels in the pituitary and serum also appeared to develop during chronic alcohol administration. However, hypothalamic and testicular i-beta E levels were markedly suppressed by chronic alcohol administration in contrast to the lack of effect observed after acute alcohol administration.(ABSTRACT TRUNCATED AT 250 WORDS)

In the United States, youth (15-24 years) suicide rates increased 191% between 1950 and 1986. This paper presents data regarding suicidal ideation and attempts, suicide-related hospitalizations, and completed suicides among Connecticut youth, comparing them with data from other states and the United States. Girls have higher rates of attempts and hospitalization, boys of completed suicide. Firearms are the suicidal method of choice for both sexes. Nonmetropolitan areas had higher rates than metropolitan. Reported suicidal ideation among students ranged from 10% to as high as 66%, while attempts range from 3% to 15%. The authors stress that caution is necessary when comparing rates, pointing to the need for standardized data collection and analysis. Reported rates of suicidal behavior are lower among Connecticut youth compared to their counterparts in other states, but suicide is increasing among young males in Connecticut and remains a major issue for health care providers.

Morphine releases endogenous opioids into the circulation of dogs. To test the stereospecificity of this effect, as well as to determine whether morphine also releases endogenous opioids centrally, which might be involved in its antinociceptive action, the effects of (-)-morphine sulfate (10 mg/kg, sc) or (+)-morphine hydrobromide on antinociception in a dog tail-flick test, on semi-quantified morphine-induced signs of salivation, emesis, defecation and ataxia, and on the plasma and cerebrospinal fluid (CSF) levels of endogenous opioid peptides were studied. Plasma and CSF levels of immunoreactive beta-endorphin (i-BE), met-enkephalin (i-ME), leu-enkephalin (i-LE), and dynorphin (i-DY) were quantified by radioimmunoassay in octadecylsilyl-silica cartridge extracts. Immunoreactive morphine (i-M) levels were measured in unextracted samples. (-)-Morphine treatment significantly increased antinociception, morphine-induced signs, i-M levels in plasma and CSF, and i-BE, i-ME, and i-LE levels in plasma, but not CSF. Levels of i-DY remained constant in plasma and CSF. (+)-Morphine treatment did not alter any of these parameters, indicating that the effects of morphine on nociception, behavioral signs, and plasma endogenous opioids in dogs were stereoselective. It is concluded that morphine does not cause an increase in immunoreactive endogenous opioid peptides in the CSF at the time of its peak antinociceptive effect.

The effectiveness of steam autoclaving on bacterial endospores placed within five types of sharps containers was tested. A variety of container physical orientations within the autoclave were evaluated. Spores were present on commercial spore strips or placed onto capped and uncapped dental needles. All strips and needles present in empty or filled containers could be sterilized within 15 minutes when the containers were placed on their sides and their vents left open. The contents of containers processed in an upward position required between 30-60 minutes of autoclaving before being sterilized. The size and shape of the containers influenced ease of sterilization.

The treatment of acute appendicitis in remote environments without the capability of surgical intervention appears to be effective when using antibiotic protocols active against both aerobic and anaerobic bacteria. A review of nine such cases treated with various antibiotic protocols was conducted and demonstrated good response in all patients. This aggressive medical management frequently resulted in complete resolution of symptoms in patients who later required elective appendectomy or who had recurrences, with similar symptoms requiring acute appendectomies. A strong index of suspicion for appendicitis must be maintained in these cases and one must rely on the medical documentation of the initial episode and proceed with a thorough surgical evaluation.

We have investigated the ontogeny of immunoreactive beta-endorphin (i-beta E) in the testes of rats from 5 to 150 days of age. i-beta E was measured by RIA in acid extracts of decapsulated testes and characterized by gel filtration chromatography. Significant age-related differences in both the levels and type of i-beta E were observed. Total levels of i-beta E in the testes were very low and barely detectable from 5-20 days of age, but rose sharply in parallel with testes weights from 20-60 days of age; thereafter, no significant changes in i-beta E were found through 150 days of age. Concentrations of i-beta E, expressed in pmol/g testis, fell precipitously between days 5 and 10 and remained relatively constant from 10-150 days. Most of the i-beta E at 5 and 15 days chromatographed like authentic beta-endorphin. However, with the onset of puberty (30-35 days) and during sexual maturation, much of the total i-beta E chromatographed like its' precursor beta-lipotropin (beta LPH). Hypophysectomy decreased the weight and total i-beta E levels of the testes to the same extent without altering the concentrations of i-beta E or the chromatographic pattern of i-beta E. These results indicate that beta E-like and beta LPH-like peptides are present in the rat testis and that age-related changes in both the levels and type of i-beta E correlate with various structural and functional aspects of testicular development.

This study tested Phares, Wilson, and Klyver's (1971) hypothesis that locus of control differences are unimportant in a situation which provides very explicit cues arousing specific expectancies regarding the locus of blame for poor performance. Two hundred and seventeen undergraduate students (134 men and 83 women) completed Rotter's I-E Scale as part of classwork in midsemester. During the last week of the semester they were routinely administered a questionnaire containing items on course evaluation, instructor evaluation, and expected grade. Expected grade was significantly correlated with ratings on several course evaluation and instructor evaluation items for internals and externals in the male, female, and total samples. However, these correlations were not significantly different for internals and externals in each sample. These results provided strong empirical support for the tested hypothesis.

We have investigated the ontogeny of, and the effect of hypophysectomy on, immunoreactive beta-endorphin in rat ovaries. Total levels rose with ovarian weight from nondetectable levels at 5 days of age to approximately 0.15 pmol/ovary at 80 days; thereafter, the levels remained constant through 201 days of age. Hypophysectomy decreased both ovarian weight and the total content of immunoreactive beta-endorphin, but the concentration per weight was not significantly altered. Most of the immunoreactive beta-endorphin before puberty chromatographed like authentic beta-endorphin, but after puberty most chromatographed like beta-lipotropin. Hypophysectomy did not alter this chromatographic pattern.

To gain further insight into the possible role of endogenous opioid peptides in the respiratory difficulties associated with the apnea of infancy and other disorders possibly related to apnea, the levels of beta-endorphin immunoreactivity were measured in the cerebrospinal fluid (CSF) of five groups of infants: (1) infants with proved apnea, (2) infants with histories of an apparent life-threatening event (ALTE), (3) siblings of victims of the sudden infant death syndrome (SIDS), (4) infants with suspected but unproved apnea, and (5) infants undergoing investigation for other acute illnesses. Twenty-two infants considered at risk for an ALTE (groups 1 to 3) had significantly higher CSF beta-endorphin equivalents (88 +/- 7 pg/mL) than did the 22 control patients in groups 4 and 5 (31 +/- 3 pg/mL). Plasma beta-endorphin immunoreactivity, which was also measured in some of the infants, did not correlate with levels in CSF and, in fact, was significantly lower in the groups at risk for an ALTE (50 +/- 9 pg/mL; n = 14) than in the control subjects (80 +/- 6 pg/mL; n = 11). These studies indicate that elevated beta-endorphin immunoreactivity in CSF may be a marker in infants who have apnea and who may be considered at risk for an ALTE.

Fourteen mildly aphasic and 14 normal speakers responded to an oral verbal fluency task for five different semantic categories. Retrieved words were scored within each 15-s time interval of a 60-s task as highly representative (i.e., having a high frequency of occurrence in a previous normative study), moderately representative (i.e., having a moderate frequency of occurrence), or highly unrepresentative (i.e., having a low frequency of occurrence). Both speaker groups were affected similarly by category type, and both retrieved words according to prior data-based notions of semantic categorical organization. The two groups differed with respect to the interaction between time intervals and representativeness levels. The different verbal fluency performance of the aphasic subjects was related to both the temporal occurrence of a word within a 60-s response interval and to its representativeness level (prototypicality) within a particular semantic category.

A gas chromatographic (GC) method has been developed for determination of cholesterol in meats. The method involves ethanolic KOH saponification of the sample material, homogeneous-phase toluene extraction of the unsaponifiables, derivatization of cholesterol to its trimethylsilylether, and quantitation by GC-flame ionization detection using 5-alpha-cholestane as internal standard. This direct saponification method is compared with the current AOAC official method for determination of cholesterol in 20 different meat products. The direct saponification method eliminates the need for initial lipid extraction, thus offering a 30% savings in labor, and requires fewer solvents than the AOAC method. It produced comparable or slightly higher cholesterol results than the AOAC method in all meat samples examined. Precision, determined by assaying a turkey meat sample 16 times over 4 days, was excellent (CV = 1.74%). Average recovery of cholesterol added to meat samples was 99.8%.

Previous X-ray studies (2.8-A resolution) on the crystals of tobacco mosaic virus protein (TMVP) grown from solutions containing high salt have characterized the structure of the protein aggregate as a bilayered cylindrical disk formed by 34 identical subunits [Bloomer, A.C., Champness, J.N., Bricogne, G., Staden, R., & Klug, A. (1978) Nature (London) 276, 362-368]. Under low-salt conditions, 20S aggregates are in equilibrium with 4S species and involved in the efficient nucleation of TMV assembly in vitro [Butler, P.J.G. (1984) J. Gen. Virol. 65, 253-279]. We have investigated by sedimentation velocity and near-UV circular dichroism (CD) measurements the structure of 20S aggregates in low salt (I = 0.1 potassium phosphate at pH 7.0 and 20 degrees C) and the aggregates in high salt [0.2 M (NH4)2SO4 in I = 0.1 tris(hydroxymethyl)aminomethane hydrochloride at pH 8.0 and 20 degrees C, close to the conditions under which TMVP crystallizes as disk aggregates]. At high salt, we observe structures (presumably stacks of disks) having s20,w values around 40, 45, and 50 S, but not the 20S species present in low-salt buffers. The near-UV CD spectrum of 20S aggregates has been obtained for the first time, using computer techniques, from the spectra of the 4S-20S equilibrium mixture and the 4S species. This spectrum of 20S aggregates differs dramatically from that of the stacks of disks examined at both high and low salt (into which the stacks can be returned by dialysis), indicating that the difference is not a solvent effect.(ABSTRACT TRUNCATED AT 250 WORDS)

It has been suggested that endogenous opioid peptides (EOP) exert paracrine or autocrine effects in the testes. To assess this hypothesis, we examined whether naloxone, by blocking the effects of EOP, influenced serum testosterone levels, apart from its effects on LHRH/LH, in the intact male rat. We found that naloxone increased serum LH and testosterone levels over essentially the same time course and produced dose-dependent increases in serum testosterone levels even though LH levels were maximally elevated at all doses. These data are not consistent with the view that naloxone exerts its effects on testosterone exclusively by altering LHRH/LH release. Additional, perhaps more definitive, evidence of a direct effect of naloxone on testosterone's biosynthesis was provided by our observations that 1) naloxone generated increases in serum testosterone levels in male rats in which the naloxone-induced surge in LH was blocked by nembutal; and 2) intratesticular injections of naloxone increased serum testosterone levels without increasing LH. Although these data suggest that naloxone influences steroidogenesis independently of its effects on LH, we found that the antagonist failed to increase serum testosterone levels in hypophysectomized animals or when serum LH levels were allowed to reach undetectable levels in nembutal-blocked animals. Consequently, our data are consistent with the hypothesis that naloxone facilitates the effects of LH on testosterone's biosynthesis rather than exerting an independent effect of its own. Whether the effects observed in these studies represent a negative autocrine effect of EOP on Leydig cells or a paracrine effect on Sertoli cells remains to be determined. Nevertheless, our results provide, to our knowledge, the first in vivo evidence that EOP modulate testicular steroidogenesis in the intact animal.

The observation that the narcotic antagonist naloxone could inhibit analgesia produced by electrical stimulation of the brain indicated the involvement of an endogenous chemical in the relief of pain. Multiple endogenous opioid peptides have been identified that have similar pharmacological properties to known narcotic analgesics. The biosynthesis, release, and degradation of opioid peptides have been studied in order to better understand how the manipulation of endogenous opioid systems can be used to produce or augment analgesia. The results of our studies reveal that various conditions and manipulations, such as electrical brain stimulation, acupuncture, stress, and the administration of opioid analgesics, can cause the release of endogenous opioid peptides and possibly endogenous nonpeptide substances. It has also been discovered that nonopioid peptides, such as cholecystokinin, calcitonin, and angiotensin II, can alter the action of opioid analgesics by antagonizing or potentiating their effects. An understanding of the role of endogenous peptides in endogenous opioid mechanisms is necessary for the development of new ways to treat pain and such other disorders as sleep apnea in children (sudden infant death syndrome), head injury, and opioid addiction that involve the activation or alteration of endogenous opioid systems.

Increased plasma beta-endorphin immunoreactivity in scuba divers after submersion. Med. Sci. Sports Exerc., Vol. 19, No. 2, pp. 87-90, 1987. After submersion under water in a motionless state of neutral buoyancy, scuba divers frequently report feelings of well-being or euphoria similar to those reported after strenuous exercise. Since strenuous exercise is associated with a stress-related increase in plasma beta-endorphin immunoreactivity (beta-EIR), this study was undertaken to measure plasma beta-EIR after submersion in a state of neutral buoyancy under conditions that do not involve strenuous exercise or other extreme stresses. Plasma beta-EIR was measured by radioimmunoassay in male scuba divers before and immediately after remaining motionless 10 ft under water in a state of neutral buoyancy. A significant (P less than 0.01) increase in plasma beta-EIR was found under these conditions. Venipuncture and scuba breathing out of the water did not alter beta-EIR levels. These results indicate that the milder stress associated with submersion in a state of neutral buoyancy involves an increase in plasma beta-EIR similar to that caused by severe stress.

A follow-up study of 35 children subjected to electrocochleography (Ecog) was conducted to determine (1) agreement of Ecog results with other audiometric measures obtained subsequently, and (2) accuracy of recommendations for patient management made on the basis of Ecog results. The latter was determined by parental experience, educational placement and achievement, and information from medical and paramedical personnel currently managing the children. These data indicate that Ecog test results are valuable in helping select between possible management alternatives in children who are not testable by behavioral means. However, discussion of two "problem" cases points to possible errors of management that could be made if Ecog results were the only available diagnostic information.

The pH dependence of the resonance Raman and absorption spectra of human methemoglobin fluoride (HbIIIF) and sperm whale metmyoglobin fluoride (MbIIIF) has been examined. Both the Raman and absorption spectra of HbIIIF and MbIIIF indicate the existence at alkaline pH of an equilibrium between the hydroxide and fluoride complexes. The absorption maxima of HbIIIF and MbIIIF solutions shift to longer wavelengths as the pH is decreased from neutrality. The Raman data show a corresponding shift of the 461- and 468-cm-1 Fe-F vibrational stretching peaks at pH 7.0 [Asher, S. A., & Schuster, T. M. (1979) Biochemistry 18, 5377] to 399 and 407 cm-1 at acid pH in MbIIIF and HbIIIF, respectively. These shifts are interpreted to result from protonation of the distal histidine and the formation of a hydrogen bond to the fluoride ligand. Measurements of the pH dependence of the absorption and resonance Raman spectra give distal histidine ionization constants (apparent) corresponding to pK = 5.1 (+/- 0.1) for HbIIIF and pK = 5.5 (+/- 0.1) for MbIIIF. An examination of the distal histidine pK values and the frequency of the hydrogen-bonded Fe--F stretching vibration at pH 5.0 of HbIIIF with and without inositol hexaphosphate indicates little difference in the distal histidine--heme distance between the so-called R and T quaternary forms of HbIIIF. These results indicate that the changes in the electronic spectrum of HbIIIF that occur upon switching from the R to the T form do not result from alterations in (1) the iron--fluoride bond distance, (2) the iron out-of-heme plane distance, or (3) the distal histidine--fluoride distance.

A number of factors which lower the oxygen affinity of hemoglobins are also known to produce shifts of the absorption band maxima of the oxyheme. We have studied the variation of the absorption spectra of oxygenated alpha SH and beta SH subunits of human Hb A as a function of their state of association (i.e. alpha, alpha 2, beta, beta 4, alpha beta, or alpha 2 beta 2), and have attempted to correlate the spectral changes with changes to O2 affinity. These studies were carried out under solution conditions (0.1 M Tris, 0.1 M NaCl, 1 mM Na2EDTA, pH 7.4, 10 degrees C) where detailed thermodynamic data for subunit association and oxygen binding are available (Ackers, G. K. (1980) Biophys. J. 32, 331-346). Concentration-difference spectra reveal that the visible and Soret absorption band maxima of beta O2 are slightly red shifted relative to beta 4O8. A unique feature of this spectral change is that the red shift is accompanied by an increase in the ratio of the peak absorbances of the visible alpha and beta spectral bands. By measuring the spectral change as a function of concentration, an association constant of 6.4 +/- 1.9 X 10(15) M-3 was determined for the 4(beta O2) in equilibrium beta 4O8 equilibrium. In contrast, no spectral differences were found between alpha O2 and alpha 2O4 or between oxy alpha beta dimers and oxyHb. Mixing experiments show that the spectrum of oxyHb differs from the average of either alpha O2 + beta O2 or alpha O2 + beta 4O8, but is closer to the former. A comparison between these spectral data and the reported O2 affinities of these species shows that affinity and oxyheme spectra are not correlated.

These studies assessed the fate and localization of incoming iron in 6-8-day rat reticulocytes during inhibition of heme synthesis by succinylacetone. Succinylacetone inhibition of heme synthesis increased iron uptake by increasing the rate of receptor recycling without affecting receptor KD for transferrin, transferrin uptake, or total receptor number. Its net effect was to amplify the number of surface transferrin receptors by recruitment of receptors from an intracellular pool. Despite increased iron influx in inhibited cells, only 2-4% of total incoming iron was diverted into ferritin. The majority of incoming iron (65-80%) in succinylacetone-inhibited cells was recovered in the stroma, where ultrastructural and enzymic analyses revealed it to be accumulated mainly in mitochondria. Intramitochondrial iron (70-75%) was localized mainly in the inner membrane fraction. Removal of succinylacetone restored heme synthesis, utilizing iron accumulated within mitochondria for its support. Thus, inhibition of heme synthesis in rat reticulocytes results in accumulation of incoming iron in a functional mobile intramitochondrial precursor iron pool used directly for heme synthesis. Under normal conditions, there is no significant intracellular or intramitochondrial iron pool in reticulocytes, which are therefore dependent upon continuous delivery of transferrin-bound iron to maintain heme synthesis. Ferritin plays an insignificant role in iron metabolism of reticulocytes.

Sedimentation and proton binding studies on the endothermic self-association of tobacco mosaic virus (TMV) protein indicate that the so-called "20S" sedimenting protein is an interaction system involving at least the 34-subunit two-turn yield cylindrical disk aggregate and the 49-subunit three-turn helical rod. The pH dependence of this overall equilibrium suggests that disk formation is proton-linked through the binding of protons to the two-turn helix which is not present as significant concentrations near pH 7. There is a temperature-induced intramolecular conformation change in the protein leading to a difference spectrum which is complete in 5 x 10(-6) s at pH 7 and 20 degrees C and is dominated at 300 nm by tryptophan residues. Kinetics measurements of protein polymerization, from 10(-6) to 10(3) s, reveal three relaxation processes at pH 7.0, 20 degrees C, 0.10 M ionic strength K (H) PO4. The fastest relaxation time is a few milliseconds and represents reactions within the 4S protein distribution. The second fastest relaxation is 50-100 x 10(-3) s and represents elementary polymerization steps involved in the formation of the approximately 20 S protein. Analysis of the slowest relaxation, approximately 5 x 10(4) s, suggests that this very slow formation of approximately 20 S protein may be dominated by some first order process in the overall dissociation of approximately 20S protein. Sedimentation measurements of the rate of TMV reconstitution, under the same conditions, show by direct measurements of 4S and approximately 20S incorporation at various 4S to approximately 20S weight ratios that the relative rate of approximately 20S incorporation decreases almost linearly, from 0 to 50% 4S. There appears to be one or more regions of TMV-RNA, approximately 1-1.5 kilobases long, which incorporates approximately 20S protein exclusively. Solutions of approximately 95-100% approximately 20S protein have been prepared for the first time and used for reconstitution with RNA. Such protein solutions yield full size TMV, but at a slower rate than if 4S protein is added. Thus the elongation reaction in TMV assembly, following nucleation with approximately 20S protein, is not exclusively dependent upon the presence of either 4S or approximately 20S protein aggregates. The initial, maximum, rate of reconstitution increases about threefold when the protein composition is changed from 5% to 30% 4S protein, at constant total protein concentration at pH 7.0, 20 degrees C in 0.10 M ionic strength K (H)PO4. The probable binding frame at the internal assembly nucleation site of TMV-RNA has been determined by measuring the association constants for the binding of various trinucleoside diphosphates to helical TMV protein rods. The -CAG-AAG-AAG-sequence at the nucleation site is capable of providing at least 10-14 kcal/mol of sites of binding free energy for the nucleation event in TMV self-assembly.