Genetic differentiation and admixture between sibling allopolyploids in the Dactylorhiza majalis complex.

Allopolyploidization often happens recurrently, but the evolutionary significance of its iterative nature is not yet fully understood. Of particular interest are the gene flow dynamics and the mechanisms that allow young sibling polyploids to remain distinct while sharing the same ploidy, heritage and overlapping distribution areas. By using eight highly variable nuclear microsatellites, newly reported here, we investigate the patterns of divergence and gene flow between 386 polyploid and 42 diploid individuals, representing the sibling allopolyploids Dactylorhiza majalis s.s. and D. traunsteineri s.l. and their parents at localities across Europe. We make use in our inference of the distinct distribution ranges of the polyploids, including areas in which they are sympatric (that is, the Alps) or allopatric (for example, Pyrenees with D. majalis only and Britain with D. traunsteineri only). Our results show a phylogeographic signal, but no clear genetic differentiation between the allopolyploids, despite the visible phenotypic divergence between them. The results indicate that gene flow between sibling Dactylorhiza allopolyploids is frequent in sympatry, with potential implications for the genetic patterns across their entire distribution range. Limited interploidal introgression is also evidenced, in particular between D. incarnata and D. traunsteineri. Altogether the allopolyploid genomes appear to be porous for introgression from related diploids and polyploids. We conclude that the observed phenotypic divergence between D. majalis and D. traunsteineri is maintained by strong divergent selection on specific genomic areas with strong penetrance, but which are short enough to remain undetected by genotyping dispersed neutral markers.

Drug use among street children in southern Brazil.

We studied the self-reported activities engaged in by children found wandering on the streets of Porto Alegre, Brazil, aiming to describe their drug abuse habits and practice of thefts or mendicancy. One hundred-and-five youngsters, 6-18 years old, were interviewed in the streets. Although the external appearance of the interviewed children lacked cues as to their life-style differences, three diverse life-style characteristics were depicted among them. Almost 25% of the children lived with their families and went to school (FAMSCH) and 46% lived with their families but didn't go to school (FAM). The other 29% spent all day long and slept in the streets (STREET). The most frequently used drug for the total group of children was tobacco, followed by alcohol, with a much higher prevalence of use of both alcohol and tobacco among children from the STREET subgroup. Alcohol was used by more than 25% of the STREET children and tobacco by 58% of the children from this subgroup, in a regular (almost daily) basis. Less than 12% of the FAMSCH children used illicit drugs. Inhalants were the preferred drugs for illicit drug experimental use. Only 4% of the children attending school sniffed solvents in a regular basis. Regular abuse of inhalants was reported much more frequently by the STREET subgroup of children, reaching a prevalence of 40%. Self-report of marijuana smoking was described to be regular by 4% of the FAMSCH children and 26% by the STREET children. A significantly higher number of the children who lived with their families in comparison to the STREET children described work activities (selling food, washing cars or polishing shoes) while out in the streets. On the other hand the practice of thefts was self-reported mainly by the children from the STREET group and only by the ones who used illicit drugs. Children who lived with their families reported less mendicancy and thefts than STREET children. These results show that very poor children might spend many hours of the day by themselves in the streets of a big city accompanied by children who are never under adult supervision. In spite of being alone for some hours a day and making friends with others who might use drugs, having a family and regularly attending school decreases the risk of delinquent acts and drug use.

Comparison of behavioral effects of moclobemide and deprenyl during forced swimming.

The present study compared the antiimmobility effects of l-deprenyl (DEP) and moclobemide (MOC) to the classic antidepressant imipramine (IMI), using an ethological approach. To investigate the degree of MAO-B inhibition by DEP and MOC, combination of treatments of ineffective doses of phenylethylamine (PHEA) with DEP or with MOC were administered in three doses before immobility was tested in the forced-swimming paradigm. Tests were videotape recorded for analysis of the frequency and duration of the behaviors during the procedure. There was a significant, dose-dependent decrease in immobility duration and an increase in mobility duration of rats treated with IMI. Both active behaviors of climbing and swimming were equally enhanced by the tricyclic antidepressant, climbing behavior composing 75% of the mobile behaviors. The intermediate doses of the MAOIs tested, DEP 0.25 mg/kg and MOC 30 mg/kg, decreased immobility and increased mobility. The antiimmobility effect of DEP was due to longer climbing behavior while MOC enhanced swimming duration. No behavioral changes were seen with the administration of the lower and higher doses of the MAOI. Potentiation of the antiimmobility effects was observed when ineffective doses of PHEA and of DEP or MOC were administered in combination. Differences between the MAO inhibitors on the active behaviors were also observed when administered with PHEA; DEP and PHEA significantly increased climbing and MOC and PHEA increased swimming. This preclinical evaluation of selective MAO inhibitors indicates that both MAO-A and MAO-B inhibitors have antidepressant effects. However, to clearly demonstrate that these antiimmobility effects are a consequence of increased brain concentrations of any one of the several monoamines implicated in the mechanism of action of DEP or MOC should be the subject of future studies.

Effect of sodium valproate on the open-field behavior of rats.

1. It has been reported that sodium valproate induces a morphine-like withdrawal syndrome in rats. The effects of acute or chronic treatment with sodium valproate on rat behavior was studied in the open-field test. 2. Acute sodium valproate (320 mg/kg, intraperitoneally) decreases the frequency of, and the time spent in grooming even when not modifying locomotion, rearing or defecation (N = 15), either 15 or 60 min after an acute treatment. This effect was not modified (N = 10) by concomitant administration of morphine (2 mg/kg) or naloxone (1 mg/kg). 3. Interruption of prolonged (30 days) valproate treatment with increasing doses of 40 to 320 mg/kg, by gavage, twice daily (N = 10) did not modify rat behavior in the open-field, from the first to the fourteenth day of the test. 4. We conclude that the decreased novelty-induced grooming does not depend on the opioid system and may be related to an anti-anxiety effect of valproate.

Effects of phenylethylamine on rat locomotor behavior and avoidance learning.

1. The effects of beta-phenylethylamine (PEA) alone and in association with caroxazone, a potent inhibitor of monoamine oxidase B (MAO B), on the activity and long-term memory in the wheel-shaped activity monitor and on fixed-interval two-way avoidance acquisition were studied in rats. In a separate study, we determined the effects of PEA and of d-amphetamine on the variable-interval two-way avoidance acquisition. 2. The action of PEA was markedly different from that of amphetamine in several aspects. The stimulating effects of PEA in the wheel-shaped activity monitor were of a more subtle nature than those of amphetamine and in the variable-interval two-way avoidance acquisition PEA had no effect, while amphetamine improved performance. 3. PEA did not induce an increase in path-choice stereotypy, but caroxazone did. The absence of any caroxazone-session interaction effects on the path iteration frequency suggested that there were no long-term memory effects. 4. In the fixed-interval two-way avoidance acquisition experiments, PEA increased the avoidance responses of rats while caroxazone had no effect. The association of the two drugs did not potentiate either.

Chronic effect of antidopaminergic drugs or estrogen on male wistar rat lactotrophs and somatotrophs.

The aim of the present study was to evaluate the effect of antidopaminergic agents on the somatotrophs in the presence of hyperprolactinemia. Adult male Wistar rats were divided into 6 groups: a control group and five groups chronically treated (60 days) with haloperidol, fluphenazine, sulpiride, metoclopramide or estrogen. Somatotrophs and lactotrophs were identified by immunohistochemistry and the data are reported as percent of total anterior pituitary cells counted. The drugs significantly increased the percentage of lactotrophs: control (mean +/- SD) 21.3 +/- 4.4, haloperidol 27.8 +/- 2.2, fluphenazine 34.5 +/- 3.6, sulpiride 32.7 +/- 3.5, metoclopramide 33.4 +/- 5.5 and estrogen 42.4 +/- 2.8. A significant reduction in somatotrophs was observed in animals treated with haloperidol (23.1 +/- 3.0), fluphenazine (22.1 +/- 1.1) and metoclopramide (24.2 +/- 3.0) compared to control (27.3 +/- 3.8), whereas no difference was observed in the groups treated with sulpiride (25.0 +/- 2.2) and estrogen (27.1 +/- 2.8). In the groups in which a reduction occurred, this may have simply been due to dilution, secondary to lactotroph hyperplasia. In view of the duplication of the percentage of prolactin-secreting cells, when estrogen was applied, the absence of a reduction in the percent of somatotrophs suggests a replication effect on this cell population. These data provide additional information about the direct or indirect effect of drugs which, in addition to interfering with the dopaminergic system, may act on other pituitary cells as well as on the lactotrophs.

Effects of carbamazepine or imipramine alone or in association with amphetamine on the fighting time of REM sleep-deprived rats.

The fighting time of REM sleep-deprived rats was measured after both acute and long-term intraperitoneal treatment with carbamazepine (CBZ) or imipramine (IMI) alone or associated with amphetamine. Fighting time was increased by the lower doses of CBZ (5-20 mg/kg) or IMI (0.5-2 mg/kg) administered acutely. At the highest dose tested, CBZ (40 mg/kg) was not significantly different from the control value, and the fighting time observed after 4 mg/kg IMI was less than that observed with 2 mg/kg. Amphetamine (2 mg/kg) alone increased the fighting time and this effect was not modified by association with 5-40 mg/kg CBZ or 0.5-4 mg/kg IMI. Long-term treatment (14 days) with CBZ (20 mg kg-1 day-1) or IMI (2 mg kg-1 day-1) significantly reduced fighting time in contrast to the increase observed with a single acute treatment at the same dose. The fighting time of rats acutely treated with amphetamine (2 mg/kg) was significantly but not completely reduced by previous long-term pretreatment with CBZ, whereas IMI pretreatment had no effect. The differences between the effects of acute and long-term treatment with CBZ cannot be explained by the development of metabolic tolerance, since serum CBZ levels were the same in both situations.

[Toxicology of toluene: aspects related to its abuse]. / Toxicologia do tolueno: aspectos relacionados ao abuso.

Toluene, present in many industrial and domestic products, is the main solvent involved in solvent abuse and occupational exposure. The main problem in studying toluene-related pathologies is the fact that it is frequently combined with other substances. This review focuses on its potential toxicity. The following subjects are discussed: pharmacologic parameters; physico-chemical features; exposure; clinical trials; experimental research; diagnosis; tolerance and dependence; acute and chronic effects; neurotoxicity; teratogenicity; psychiatric disorders; carcinogenicity; and treatment. It is concluded that is important more research on larger population samples with a view to better definition of the consequences of chronic use should be undertaken.

Enhanced detection of hyperactivity after drug withdrawal with a simple modification of the open-field apparatus.

The open-field apparatus has been used to study withdrawal reactions from chronic treatments with central nervous system depressant drugs. To study the behavior of the same animal after drug withdrawal, the rats are introduced into the open field on consecutive days. Because the open field is a novel environment, the repetition could lead to false-negative results with regard to drug withdrawal. To overcome this problem, we sought a modification of the open field, using different floor-painting patterns every time the animal is observed. The most frequently observed withdrawal manifestation was hyperactivity. We verified that long-term treatment withdrawal reactions from barbital, clonazepam, and ethanol were seen more often if the rats were introduced in the modified open field. In addition, fewer animals were used here than in other trials and hyperactivity was detected more frequently in the modified open field than was sound-induced convulsions. We propose that the modified open field is more useful than the classic one for screening of drug withdrawal reactions.

The effects of GABAergic drugs on grooming behaviour in the open field.

In a previous study it was demonstrated that sodium valproate, a drug that increases GABA cerebral concentrations, decreases grooming in the open field. This effect was not modified by morphine or naloxone. To provide evidence for the participation of the GABA system in the expression of grooming, other GABAergic drugs were acutely administered to rats before the test in the open field. The drugs, in the doses tested, did not modify locomotion, rearing, freezing or defaecation. Aminooxiacetic acid 10 mg/kg, barbital 60 mg/kg, baclofen 1.5 mg/kg, clonazepam 0.1 mg/kg, sodium valproate 150 mg/kg and 4,5,6,7-tetrahydroxi-azolo-5,4c-pyridine-3-ol (THIP) 0.75 mg/kg were the lowest doses to decrease the frequencies of grooming. The estimated ED50 to suppress grooming behaviour in the open field were 1.75 mg/kg baclofen, 52 mg/kg barbital, 0.86 mg/kg clonazepam and 1.0 mg/kg THIP. The decrease in grooming produced by the lowest effective doses of aminooxiacetic acid, clonazepam, sodium valproate and THIP was antagonized by concomitant administration of picrotoxin 1 mg/kg or bicuculline 1 mg/kg. The effects of baclofen and barbital on grooming were not modified by the antagonists. It is concluded that the GABA system, through GABA A and GABA B receptors may play a role in the expression of novelty-induced grooming behaviour.

Lack of tolerance to imipramine or mianserine in two animal models of depression.

Few clinical reports describe tolerance induced by antidepressants and this question is considered an unsolved problem for clinical use of this group of drugs. The present report deals with the effects of imipramine and mianserine on two animal models of depression, after acute or prolonged previous treatment with these antidepressants. Imipramine and mianserine potentiated amphetamine-induced anorexia both after acute administration or after prolonged previous treatment with each drug. Mianserine effects were not detected in the behavioral despair test and imipramine reduced rats immobility equally after acute and prolonged previous treatment. It was concluded that imipramine and mianserine do not induce detectable tolerance when previously administered to animals submitted to amphetamine anorexia or behavioral despair.

An epidemiologic study of headache among children and adolescents of southern Brazil.

To study the epidemiology of pediatric headache, we conducted a cross-sectional study of a randomized and proportional sample of 538 male and female students, 10 to 18 years old. They were in the 5th to 8th grade of the schools of Porto Alegre, RS, Brazil. The headache disorders were classified on the basis of clinical interview as well as a physical and neurological examination using the operational diagnostic criteria of the International Headache Society (IHS). The following headache prevalences were found: lifetime, 93.2%; last year, 82.9%; last week, 31.4%; last 24 h, 8.9%. Last week and last 24 h headache complaints were twice as prevalent in the female group. During the last year the prevalence of headache disorders was 72.8% for tension-type and 9.9% for migraine headache and was not associated with age distribution. Only the last year and last week prevalences of tension-type headache were significantly higher in the female group. The last year prevalence of headache disorders proved to be positively associated with sex and age variables. The prevalence of headache disorders was found to be extremely high in this population group, requiring more attention on the part of investigators as a public health problem.

Dissimilar effects of lithium and valproic acid on GABA and glutamine concentrations in rat cerebrospinal fluid.

1. This study compared the effects of the antimanic drugs, lithium and valproic acid, on GABA and glutamine CSF concentration and on head-shakes during hyponatremia. 2. Hyponatremic and normonatremic rats were treated with 2 mEq/kg lithium and 360 mg/kg valproic acid. Behavioral observation was conducted for 120 min after which blood and CSF collection were performed under anesthesia. 3. Peritoneal dialysis with glucose induced moderate hyponatremia and doubled glutamine CSF concentrations. Both lithium and valproic acid significantly increased GABA CSF levels in normonatremic and hyponatremic animals. Valproic acid induced head-shakes and increased CSF glutamine concentration. 4. The results suggest that both antimanic drugs have similar effects on GABA, but lithium is preferred if the increase in glutamine concentration poses a problem, either in the presence or absence of hyponatremia.

Lithium and valproate combined administration: acute behavioural effects and drug plasma levels.

Drug plasma concentrations and behavioural effects of acute combined administration of lithium and valproic acid were studied in normonatraemic and hyponatraemic rats. Hyponatraemia was induced two hours before drug administration and behavioural observations lasted for two additional hours. Blood was collected by the end of the behavioural observation. The higher doses of valproic acid (360 mg/kg) or lithium (2 mEq/kg) induced more head-shakes and higher plasma concentration than 180 mg/kg of valproic acid or lithium 1 mEq/kg, respectively. Valproic acid and lithium administered separately induced more head shakes and higher drug plasma levels in hyponatraemic rats than in normonatraemic animals. Combined administration of valproic acid (180 mg/kg) and lithium (2 mEq/kg) produced a supra-aditive effect in head-shakes. The drug interaction between lithium and valproic acid induced a decrease in valproic acid plasma level and an increase in lithium plasma levels.

Analgesic use for headache treatment by schoolchildren of southern Brazil.

The importance of the use of analgesic medication for the symptomatic relief of pain has been underestimated in medical practice. The objective of this study was to determine the prevalence of tension-type and migraine-type headaches and the associated analgesic consumption for its treatment within elementary school students from Porto Alegre (Brazil). A systematic random sample of 538 students from 5th to 8th grades was produced to complete the cross-sectional delineation. Subjects were individually submitted to a structured interview on headache and to general physical and neurological examination. Lifetime prevalence for headaches was 93.3%, 82.9% of the students recalled having headaches during the last year and 31.4% reported headaches in the last week. The prevalence for headaches in the previous 24 h was 8.9%. There was a significant prevalence of headache in females. The prevalence of analgesic consumption was 84.1% throughout life, 85.7% in the last year, and 54% in the last 3 months. A significantly higher prevalence of headache medication consumption was also depicted for females. However, the small age differences within the sample did not appear to be an important factor in influencing analgesic use for headaches. Different agents composed the individual treatment of headaches, with predominant use of over-the-counter preparations. Acetylsalicylic acid, consumed by 58.3% of the children, was the drug most frequently used for both tension-type and migraine-type headache treatments. In spite of the verification that headache was very frequently experienced by the children composing this sample accompanied by a consequent use of analgesics, no medication abuse was diagnosed.

Does intratesticular testosterone administration modify the evolution of transitory testicular ischemia in pre-pubertal rats?

PURPOSE: Testicular torsion followed by ischemia results in variable degrees of infertility and until now there appears to be no effective way to recover it. Testosterone participation in the maintenance of male sexual organs and spermatogenesis led us to hypothesize that intratesticular administration could recover ischemic injury. MATERIALS AND METHODS: We divided 40 Wistar rats in 2 groups, of 20 each. One group was control and the other underwent a 120-minute testicular ischemia by means of a vascular clamp on the left spermatic cord. Each group was further subdivided in 2 subgroups. The first one was observed and the second received intratesticular testosterone 25 mg. starting on the third day after injury and during the next 7 consecutive days. Half the animals were sacrificed 30 days after injury and the remaining ones after 60 days. Weight, volume, number of seminiferous tubules, histology and spermatogenesis of the same side and contralateral testes were examined. For statistical analysis ANOVA and Fisher's tests were applied. RESULTS: It was found that testosterone was capable of acting upon volume and weight of the left testis (p=0.0001). The animals receiving intratesticular testosterone showed lower testicular weight and volume after 30 and 60 days, respectively. This subgroup also showed a higher number of seminiferous tubules, modified histology and absent spermatogenesis suggesting testicular atrophy. CONCLUSIONS: We concluded that intratesticular injection of testosterone 25 mg. once a day during 7 consecutive days after transitory testicular ischemia causes ipsilateral testis atrophy. The animals in control group showed testicular histological recovery 60 days after injury. There were no significant histological differences in the contralateral testes.

Hematological alterations in rats from xylene and benzene.

Benzene and xylene are used by the chemical industry as raw materials for the manufacturing of paints, insecticides, gums, resins and other compounds. Through its myelotoxic actions, benzene produces hematologic changes ranging from pancytopenia to total bone marrow aplasia. The present investigation studied the possible effects of xylene on rat peripheral blood and compared these effects to those produced by benzene. Thirty-six male Wistar rats were injected s.c. with 2 ml benzene, xylene or saline/kg body weight 3 times a week at 2-3 d intervals for 5 w. The animals were lightly anesthetized and blood was collected by puncture of the retro-orbital plexus before the first administration of the solvents on d 7, 14, 21 and 35 of dosing, and 14 d after dosing was discontinued. Xylene induced leukocytosis as an increase in absolute neutrophil numbers, whereas benzene caused leukocytopenia due to decreases in absolute lymphocyte number. The 2 solvents reduced erythrocyte counts, hematocrit and hemoglobin. Platelet counts were high throughout the dosing with benzene and xylene. Fourteen d after discontinuation of xylene dosing, the rats recovered their initial hematologic values, whereas the animals dosed with benzene did not fully recover leukocytes and erythrocytes. The intoxications with benzene and xylene were not solely hematologic since there was also growth retardation, as shown by reduced weight gain, which did not recover after dosing ceased.