Reduction in sexual risk behaviors among college students following a comprehensive health education intervention.

Sexually active college students are at risk of contracting sexually transmitted diseases, including HIV infection. As a result, health education initiatives to prevent these infections are commonplace, but few controlled research studies have evaluated behavioral changes as a result of on-campus sex education. In a nonrandomized control trial, sexual risk behaviors of 341 students who had received a comprehensive health education intervention in a first-year seminar were compared with 227 students who were not enrolled in the seminar. The seminar curriculum included an intervention addressing facts about sexually transmitted diseases, safer sex, values, decision making, and assertiveness skills. Sexual abstinence (no sexual intercourse), number of sexual partners, consistent condom use, and methods of contraception were assessed at baseline and after 3 months. Compared with students who had not received the intervention, men in the seminar reported increased sexual abstinence but no change in consistent condom use; the women in the intervention group reported no change in sexual abstinence but an increase in consistent condom use. Women who had not received the intervention reported never using a condom more frequently than women who had received the intervention. The health education intervention on a college campus was associated with short-term reduction in sexual risk behaviors, but the reduction varied according to the students' gender.

New, special stain for histopathological diagnosis of cryptococcosis.

The Masson-Fontana silver stain for melanin was employed for the differentiation of pathogenic fungal species in human or mouse tissues. The fungi studied were Candida albicans, Candida tropicalis, Candida glabrata (Torulopsis glabrata), Cryptococcus neoformans, Cryptococcus bacillisporus, Coccidioides immitis, Blastomyces dermatitidis, Histoplasma capsulatum, Paracoccidioides brasiliensis, Sporothrix schenckii, Rhizopus rhizopodiformis, and Aspergillus fumigatus. The tissue sections stained with Masson-Fontana silver stain showed a dark brown to black color in the wall of cryptococci, whereas the walls of remaining fungal species were hyaline, except for those of S. schenckii. The yeastlike cells of S. schenckii showed faint brown pigment on the wall. Cultures of these fungi showed staining characteristics identical to those of the in vivo results. Cultures of four nonpathogenic Cryptococcus species, Cryptococcus uniguttulatus, Cryptococcus laurentii, Cryptococcus terreus, and Cryptococcus luteolus, were also tested for staining by the Masson-Fontana procedure. Of these, only C. laurentii stained positively, and the pigment on the cell wall was as intense as that of the cells of C. neoformans. These results indicate that the Masson-Fontana silver stain can be used as a specific stain in the histological diagnosis of cryptococcosis.

Relationship between polyene resistance and sterol compositions in Cryptococcus neoformans.

Six mutants of Cryptococcus neoformans resistant to nystatin and pimaricin and three mutants resistant to amphotericin B were isolated by ultraviolet irradiation techniques from two wild-type strains. The major sterols of the wild-type strains were Delta(7)-ergosten-3beta-ol and ergosterol. All six mutants resistant to nystatin and pimaricin showed either loss of ergosterol and concurrent production of Delta(7, 22)-ergostadien-3beta-ol and Delta(7)-ergosten-3beta-ol, or loss of both the wild-type sterols, with production of Delta(8(9))-ergosten-3beta-ol and Delta(5, 8(9), 22)-ergostatrien-3beta-ol. The mutants producing Delta(7, 22)-ergostadien-3beta-ol and Delta(7)-ergosten-3beta-ol showed relatively low levels of resistance to nystatin and pimaricin, whereas the mutants producing Delta(8(9))-ergosten-3beta-ol and Delta(5, 8(0), 22)-ergostatrien-3beta-ol showed a high level of resistance to either drug. Although highly resistant to amphotericin B, however, the three mutants produced sterol compositions identical to those of the wild types, indicating that the strains acquired resistance other than by alteration of the membrane sterols. The mutants producing Delta(8(9)) and Delta(5, 8(9), 22) sterols were not virulent for mice, showed reduced growth rates at 25 C, and failed to grow at 37 C. The other mutants showed a slightly reduced rate of growth both at 25 and 37 C, and the virulence in mice was slightly reduced in comparison with that of the wild types. These comparisons were on gross observations and were not statistically analyzed.

Koch's stulates and experimental ocular histoplasmosis.

The present study shows clearly that focal choroiditis is produced in rabbits by infecting the animals with a mycelial form of H. capsulatum. Identification of this organism as the pathogenic agent was made by histopathological and mycological observations. This fungus was recovered from infected ocular lesions in those eyes enucleated within four weeks following the appearance of uveitus-a time period consistent with the clinical and pathological appearance of multiple granulomas in the choroid. The absence of organisms in the contralateral eyes of these same animals at eight weeks suggests perhaps that recovery was associated with the emergence of immunity by two months following the appearance of uveitus. This is supported in part by our previous study, which supplied evidence that animals were protected from further uveitis on subsequent reinfections (after they had recovered from their initial infection) by a mycelial or yeast form of the fungus. Similar protection was also seen in animals that had prior exposures to heat-killed organisms. Moreover, onset of the ocular changes occurred usually two weeks after infection. This evidence strongly suggests that the experimental choroiditis may be immunologically induced. H. capsulatum recovered from infected eyes (Groups I and II) produced identical ocular lesions clinically and histopathologically when injected into normal animals (Groups IA and IIA). Fulfillment of Koch's postulates in experimental ocular histoplasmosis was achieved within only one month following the appearance of uveitis. This may be of fundamental importance in that efforts to demonstrate a causal relationship between the ocular picture and benign systemic histoplasmosis have been unsuccessful in man. Because of the striking similarity between the experimental choroiditis in rabbits and the changes observed in presumed ocular histoplasmosis in man, studies in primates are necessary. Since the ocular anatomy is similar in monkeys and in man, there remains the necessity to reproduce the hemorrhagic disciform lesion of the macula, which represents the gravest aspect of presumed ocular histoplasmosis.