Dating preferences of university women: an analysis of the nice guy stereotype.

Many researchers have attempted to discover what types of men women consider most desirable for relationship partners. This study investigated university women's (N = 165) perceptions of "nice guys," specifically whether women perceived nice guys to be more or less sexually successful than guys who are considered not nice. Both quantitative and qualitative analyses were used. The qualitative analysis was useful in understanding women's differing interpretations of the nice guy label. More than one half of the women agreed that nice guys have fewer sexual partners. However, more than one half also reported a preference for a nice guy over a bad boy as a date. As hypothesized, women who placed a lesser emphasis on the importance of sex, who had fewer sexual partners, and who were less accepting of men who had many sexual partners were more likely to choose the nice guy as a dating partner. The findings indicate that nice guys are likely to have fewer sexual partners but are more desired for committed relationships.

Spinal extradural hematoma in an infant with hemophilia A: an unusual presentation of a rare complication.

Epidural hematomas are a rare complication of hemophilia. This article documents the first case of an infant who initially had irritability alone without neurologic symptoms. The infant's disease was diagnosed and treated early and the child had a good neurologic outcome.

Gender differences in toxicokinetics, liver metabolism, and plasma esterase activity: observations from a chronic (27-week) toxicity study of enalapril/diltiazem combinations in rats.

Diltiazem (DTZ), a calcium channel blocker, and enalapril (EN), an angiotensin-converting enzyme inhibitor, are being developed as combination therapy for cardiovascular disease. A toxicokinetic evaluation of EN and DTZ drug levels during a 27-week toxicity study used an enzyme assay to measure EN and an HPLC assay to measure DTZ, deacetylated DTZ (DAD), and desmethyl DTZ (DMD). EN exposure during drug week 7 was proportional to dose and without dispositional gender differences. However, gender differences in DTZ and metabolite plasma profiles were dramatic. For example, female DTZ Cmax values were roughly 15-20% of males; DAD plasma Cmax values were roughly 3- to 10-fold greater; and the desmethyl metabolite, DMD, was roughly 2- to 10-fold lower. Sodium fluoride added to samples taken during drug week 26 to inhibit plasma esterase activity did not alter DTZ plasma profiles, suggesting that gender differences in DTZ and metabolite plasma levels were not caused by sample degradation. Liver esterase activity in treated rats was significantly greater (p > 0.05) than controls, whereas plasma activity was not affected. Female plasma and liver esterase activities were roughly 3- and 5-fold greater than males (p < 0.002), respectively, which may explain the low DTZ and high DAD plasma levels we measured. These results indicate that liver and plasma esterase activity is much greater in female rats and may be responsible for the differences in drug and metabolite plasma profiles relative to males. In addition, chronic coadministration of EN/DTZ may modestly increase liver esterase activity.

Stable photobleaching of P840 in Chlorobium reaction center preparations: presence of the 42-kDa bacteriochlorophyll a protein and a 17-kDa polypeptide.

Simple procedures for the anaerobic preparation of photoactive and stable P840 reaction centers from Chlorobium tepidum and Chlorobium limicola in good yield are presented and quantitated. The subunit composition was tested by cosedimentation in sucrose density gradients. For C. limicola, it minimally comprises four subunits: the P840 reaction center protein PscA, the BChla antenna protein FMO, the FeS protein PscB with centers A and B, and a positively charged 17-kDa protein denoted PscD. The preparation from Chlorobium tepidum additionally contained PscC, a cytochrome c-551. The BChla absorption peak of the purified complexes was at 810 nm, with a shoulder at 835 nm. The ratio of the shoulder to the peak was 0.25, which corresponds to 1 reaction center per 70 BChla molecules if a uniform extinction coefficient of BChla is assumed. However, bleaching at 610 nm in continuous light corresponded up to 1 photoactive reaction center per 50 BChla molecules. Therefore, either the extinction coefficient of BChla in the reaction center is overestimated or the one for photobleaching is underestimated. In any case, the major portion of the reaction center was photoactive in the preparations. A P840 reaction center subcomplex, lacking PscD and deficient in FMO and PscB, but retaining the cytochrome c subunit, was obtained as a side product. It was photoinactive and had an absorption peak at 814 nm and a 835/814 absorbance ratio of 0.42. FMO and PscB show the tendency to form a complementary subcomplex. FMO and PscD are apparently required to stabilize the photoactive reaction center, while the cytochrome c subunit is not.

CYP1A1 specificity of Verlukast epoxidation in mice, rats, rhesus monkeys, and humans.

It has previously been shown that Verlukast is converted to Verlukast dihydrodiol in microsomes from beta-naphthoflavone (BNF)-treated, but not uninduced Swiss Webster mice and Sprague-Dawley rats. We have examined the involvement of CYP1A1 in this reaction in more detail. It is concluded that this reaction is catalyzed exclusively by CYP1A1 in rats, mice, and humans based on the following criteria: 1) the epoxidation of Verlukast is negligible in uninduced rats, which express CYP1A2 but not CYP1A1; 2) Verlukast epoxidation is highly inducible by BNF treatment (60- to 200-fold); 3) Verlukast epoxidation in BNF-treated rat microsomes was inhibited by alpha-naphthoflavone (ANF) treatment, indicating that this activity was mediated by the CYP1A subfamily; 4) > 95% of Verlukast epoxidation in BNF-treated rat microsomes was inhibited by antibodies raised against CYP1A1; and 5) Verlukast was epoxidized by human CYP1A1 but not CYP1A2. Thus, Verlukast epoxidation appears to be specific for rat, mouse, and human CYP1A1. Additional studies showed that Verlukast was metabolized to Verlukast dihydrodiol in microsomes from uninduced rhesus monkeys. This reaction was inhibited by nanomolar concentrations of ANF in rhesus monkey microsomes implicating the involvement of the CYP1A subfamily. In addition, the 8-hydroxylation of R-warfarin, a pathway that is selective for rodent and human CYP1A1 activity, was also catalyzed at significant rates by rhesus monkey microsomes. These findings indicate that, unlike rats, mice, and humans, which have very low constitutive levels of hepatic CYP1A1 activity, the uninduced rhesus monkey is able to catalyze reactions specific to CYP1A1 in rodents and humans.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of verlukast metabolites arising from an epoxide intermediate produced with hepatic microsomes from beta-naphthoflavone-treated rodents (P-4501A1).

Verlukast, (R)3-((((3-(2-(7-chloroquinolin-2-yl)-(E)-ethenyl)phenyl)-3- dimethylamino-3-oxopropylthio)methyl)thio)-propionic acid (also known as MK-0679 and L-668,019), is a potent leukotriene D4 antagonist. Verlukast was incubated with hepatic microsomes from beta-naphthoflavone (beta NF) or isosafrole-treated rodents to evaluate whether P-4501A1 or 1A2 mediated biotransformations could occur. With beta NF-induced mouse or rat microsomes, in which the induction of P-4501A1 had been proven by Western blot analysis, incubations produced new metabolites that were separated by reversed-phase HPLC and were initially characterized by UV (photodiode array). Metabolites were subsequently isolated and characterized by NMR and MS, and were assigned as the 5",6"-dihydrodiol and 6"-phenol (on the quinoline ring). The presumed 5",6"-epoxide intermediate was also detected and was characterized by UV (photodiode array) and MS. Microsomes from isosafrole-treated rodents produced the dihydrodiol to a much lesser extent and did not yield any other new metabolites. alpha-Naphthoflavone inhibited the dihydrodiol formation in incubations with microsomes from isosafrole- and beta NF-treated rats. In incubations with microsomes from beta NF-treated rats, to which the epoxide hydrolase inhibitor 3,3,3-trichloropropene 1,2-oxide had been added, the formation of dihydrodiol was inhibited, consistent with a microsomal epoxide hydrolase hydrolysis of the epoxide intermediate. When glutathione was added to incubations with microsomes from beta NF-treated rats, the dihydrodiol, phenol, and epoxide peaks were reduced in size and a new material, the glutathione adduct, was formed.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS and sex tourism.

PIP: Tourists traveling internationally lower their inhibitions and take greater risks than they would typically in their home cultures. Loneliness, boredom, and a sense of freedom contribute to this behavioral change. Some tourists travel internationally in search of sexual gratification. This motivation may be actively conscious or subconscious to the traveler. Billed as romantic with great natural beauty, Thailand, the Philippines, Brazil, the Dominican Republic, and Kenya are popular destinations of tourists seeking sex. The Netherlands and countries in eastern Europe are also popular. With most initial cases of HIV infection in Europe having histories of international travel, mass tourism is a major factor in the international transmission of AIDS. While abroad, tourists have sex with casual partners, sex workers, and/or other tourists. Far from all tourists, however, carry and consistently use condoms with these partners. One study found female and non white travelers to be less likely than Whites and males to carry condoms. The risk of HIV infection increases in circumstances where condoms are not readily available in the host country and/or are of poor quality. Regarding actual condom use, a study found only 34% of sex tourists from Switzerland to consistently use condoms while abroad. 28% of men in an STD clinic in Melbourne, Australia, reported consistent condom use in sexual relations while traveling in Asia; STDs were identified in 73% of men examined. The few studies of tourists suggest that a significant proportion engage in risky behavior while traveling. HIV prevalence is rapidly increasing in countries known as destinations for sex tourism. High infection rates are especially evident among teenage sex workers in Thailand. Simply documenting the prevalence of risky behavior among sex tourists will not suffice. More research is needed on travelers and AIDS with particular attention upon the motivating factors supporting persistent high-risk behavior.^ieng

Canadian tourist and Dominican Republic sex workers.

PIP: The Dominican Republic is a popular tourist destination for Canadians. The country's sex industry for tourists developed markedly in the 1980s. The Puerto Plata/Sosua area is currently one of the most popular tourist sites and claimed the highest incidence of AIDS in 1989 at 23.2 cases/100,000 people. Two pilot phases of the Dominican Sex Workers and Canadian Tourists Study have been conducted to obtain methodological and empirical data to use in developing a major study of sex and tourism. First phase interviews were held only with beachboys who make money by having relations with female tourists, while phase two interviews were held with beachboys, female sex workers, and female and male tourists. Results indicate that female tourists consider their relations with male sex workers to be primarily social, while male tourists see their relations with female sex workers as more casual, sexual, and monetarily based. Further, women are more likely than men to continue their relationships with sex workers after returning to Canada; many help their men to immigrate and some get married. To learn more about the dynamics of tourism, sex, and AIDS prevention, the author proposes individual studies exploring the characteristics of each of the following four populations: male and female sex workers and male and female tourists.^ieng

Enantioselective induction of peroxisomal proliferation in CD-1 mice by leukotriene antagonists.

The effects of a racemic leukotriene antagonist (MK-0571) and its component enantiomers (L-668,018 and L-668,019) on hepatic peroxisome proliferation were examined in mice, rats, and rhesus monkeys. Administration of racemic MK-0571 to mice resulted in increased liver weights, increased peroxisomal volume density, and a pleiotropic induction of characteristic peroxisomal and nonperoxisomal enzyme activities associated with peroxisomal proliferation. When the individual enantiomers of MK-0571 were administered to mice, a pronounced enantioselective induction of peroxisome proliferation was observed. Toxicokinetic studies showed that the levels of each enantiomer in the liver or plasma after separate administration were similar. Thus, the enantioselectivity in the induction of peroxisome proliferation could not be explained on the basis of pharmacokinetic differences between the enantiomers. The hepatic peroxisomal response of the rat to MK-0571 was greatly attenuated compared to the mouse. As has been seen with other peroxisome-proliferating agents, MK-0571 had no effect on either peroxisomal volume density or peroxisomal enzyme activity in monkeys. Due to the high degree of enantiomeric discrimination toward the induction of peroxisomal proliferation by these enantiomers, compounds of this type may prove useful as probes to examine the mechanisms by which peroxisomal proliferating agents induce their effects.

Studies of early hepatocellular proliferation and peroxisomal proliferation in Sprague-Dawley rats treated with tumorigenic doses of clofibrate.

Clofibrate, a peroxisome proliferator, is hepatocarcinogenic in rats in a dose-dependent fashion. While there is a relationship between peroxisome proliferation and rodent liver carcinogenesis, recent evidence also suggests an association between the tumorigenicity of peroxisome proliferators and sustained cell proliferation. To investigate the role of early cell proliferation in clofibrate-induced carcinogenesis and the predictive potential of this endpoint, in a 3-month study, rats were fed clofibrate doses equivalent to those used in the chronic bioassay, and cell proliferation was determined after 1 week and 3 months, using a 1-week continuous bromodeoxyuridine (BrdU)-labeling technique. Adult Sprague-Dawley rats were fed clofibrate at 1500, 4500, or 9000 ppm. Six rats/sex/group were killed after 1 or 13 weeks of treatment. Osmotic minipumps containing BrdU were implanted into rats 7 days prior to necropsy to determine the cumulative 7-day hepatocyte labeling index immunohistochemically. A dose-related increase in hepatocyte labeling index was seen after 1 week of treatment. However, at 13 weeks, sustained increases in hepatocyte proliferation were not seen; but a dose-related decrease in the hepatocyte labeling index was observed. Liver stereology at 13 weeks demonstrated a dose-related increase in liver weight and volume, but a decrease in hepatocyte nuclei per unit volume, a minimal increase or no change in the total number of hepatocyte nuclei per liver, and an absolute decline in the total number of BrdU-labeled hepatocyte nuclei per liver. These data suggest that in rats, clofibrate may influence hepatocarcinogenicity by decreases in normal hepatocyte proliferation over time and this effect may influence the pathogenesis of tumors at time points beyond 13 weeks of treatment.

Anesthesia and muscle relaxation with intrathecal injections of AR636 and AG489, two acylpolyamine spider toxins, in rat.

Acylpolyamine toxins are constituents isolated from many invertebrate predator venoms. These toxins are structurally novel and potent noncompetitive ligand-mediated ion channel antagonists. This study was designed to explore the sensory and motor effects of intrathecally applied acylpolyamine toxin. AR636 and AG489, acylpolyamine toxins from the spiders Argiope aurantia and Agelenopsis aperta, respectively, were injected intrathecally into rats prepared with chronic spinal catheters, and the effect on spinal function was assessed. AR636 was found to evoke a dose-dependent incidence of muscle flaccidity as well as a blockade of the agitation otherwise evoked by noxious mechanical and thermal stimuli applied to the tail or hind paws. AR636 has a calculated effective concentration (EC50) of 2 micrograms for motor inhibition and 7 micrograms for sensory inhibition. In contrast, AG489 was not found to have any effects at the highest tested dose of 50 micrograms. The precise mechanism whereby AR636 exerts its action in the rat spinal cord is not known, but in insect models, this agent is known to act as a postsynaptic, noncompetitive antagonist at a glutamate receptor and to block cholinergic-gated ion channels. Thus, this agent, a representative of the acylpolyamine toxins, has prominent effects on the sensory and motor systems of mammals, and this class of agents may be found to have potential application as spinally acting muscle relaxants and/or anesthetics.

Parents and AIDS education.

The objective of this research was to study parents' attitudes toward AIDS education in schools. Questionnaires were mailed to employees in an industrial plant and a hospital in a city of 150,000 in Ontario, Canada. Two hundred and sixteen questionnaires from parents with children in schools were analyzed. Two thirds of the parents agreed that AIDS education should discourage premarital sex; whereas, 88% believed that AIDS education should teach about condoms. Pearson correlations and multiple regression were used to analyze hypotheses that tested attitudes toward AIDS education in the schools. Two predictor variables--attitude toward premarital intercourse and fear of casual contact of AIDS--were significantly correlated with all three measures of attitudes toward AIDS education in the schools. Church attendance and knowledge of AIDS were related to both attitudes toward discouraging premarital sex and teaching about condoms. Three multiple regression models were constructed to predict attitudes toward AIDS education in the schools. The final models accounted for between 11% and 33% of the variance.

Thiobenzamide-induced hepatotoxicity: effects of substituents and route of administration on the nature and extent of liver injury.

Differences in the nature and extent of hepatic injury were examined after administration of para-substituted thiobenzamides to rats. In accordance with previous studies, the extent of hepatotoxicity varied with the electron-donating ability of the substituent. There was also a good correlation between the extent of hepatic necrosis and the amount of substituted thiobenzamide sulfoxide found in the plasma after intraperitoneal dosing. The nature of the hepatic lesion, characterized as a combination of hepatic necrosis, ballooning degeneration, and biliary dysfunction, varied qualitatively with each thiobenzamide analog. When the hepatotoxicity of thiobenzamide was compared after either intraperitoneal or oral dosing, differences in the extent of hepatic necrosis, ballooning degeneration, transaminase elevation, and biliary dysfunction were observed. Intraperitoneal dosing with thiobenzamide gave less severe necrosis and more pronounced elevations in bile acids, while oral dosing led to more severe necrosis along with impaired biliary function. The route of administration was shown to dramatically affect the pharmacokinetics of thiobenzamide and thiobenzamide sulfoxide. Intraperitoneal administration of thiobenzamide gave high plasma and liver levels of both thiobenzamide and thiobenzamide sulfoxide, whereas oral administration gave slightly lower levels of the sulfoxide but much lower levels of thiobenzamide. The reason for greater hepatic necrosis after oral administration may be due to a greater ability to further metabolize the sulfoxide to a reactive metabolite in the absence of high levels of thiobenzamide.

Sex education and the prevention of STD/AIDS and pregnancy among youths.

The prevention of unwanted pregnancy and STD/AIDS are two major goals of health educators. Usually these are discussed as separate goals. In this paper both of these health concerns are presented from a behavioural preventive perspective. Our objective is to outline the essential components to be used by health educators in school-based sex education programs focussing on the prevention of unwanted pregnancy and STD/AIDS.

Insulin-like effects of ATP on adipocyte pyruvate dehydrogenase and phosphorylase.

Extracellular ATP stimulated adipocyte pyruvate dehydrogenase in a time- and dose-dependent manner with an EC50 of 0.1 mM. The maximal effect was observed at 0.5 mM ATP after a 15-min incubation with a lag period of about 5 min. Depletion of intracellular Ca2+ with ethylene glycol bis(beta-aminoethyl ether) N,N'-tetraacetic acid reduced the effect of ATP by 50% and completely abolished the stimulatory effect of vasopressin on adipocyte pyruvate dehydrogenase but had no effect on the stimulation induced by insulin or adenosine. The effects of insulin and ATP on pyruvate dehydrogenase were glucose-dependent whereas the effect of adenosine was glucose-independent. Furthermore, ATP, like insulin, partially blocked the stimulatory effect of isoproterenol on phosphorylase. Adenosine, at a concentration of 1 mM, did not affect either basal or isoproterenol-stimulated phosphorylase activities. It is concluded that ATP activates adipocyte pyruvate dehydrogenase by at least two separate mechanisms: one is Ca2(+)-dependent and the other is Ca2(+)-independent. However, neither is the result of the formation of adenosine from ATP through hydrolysis.

Two classes of channel-specific toxins from funnel web spider venom.

1. The paralytic effects and neuromuscular actions of Agelenopsis aperta venom on insects were analyzed biochemically and electrophysiologically. 2. Paralysis caused by Agelenopsis venom is correlated with two effects on neuromuscular transmission: postsynaptic inhibition and presynaptic excitation. These effects are explained by the actions of two classes of toxins purified by RPLC, the alpha- and mu-agatoxins. 3. The alpha-agatoxins are low molecular weight, acylpolyamines which cause rapid, reversible paralysis correlated with use-dependent postsynaptic block of EPSPs and ionophoretic glutamate potentials. The mu-agatoxins are cysteine-rich polypeptides which cause irreversible paralysis and repetitive action potentials originating in presynaptic axons or nerve terminals. 4. The joint actions of the alpha- and mu-agatoxins lead to significantly higher rates of paralysis than are obtained by either toxin class alone, and this may relate to enhancement by excitatory mu-agatoxins of use-dependent block caused by alpha-agatoxins.