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R C Hahn

Publications and source records attributed to R C Hahn.

10 recordsLinked to original sources
PubMed2003

Factors associated with the prevalence of Malassezia species in the external ears of cattle from the state of Minas Gerais, Brazil.

Swabs collected from the external ears of 942 cattle, including both European and zebu breeds, were used to evaluate the epidemiology of Malassezia species. High numbers of Malassezia isolates were significantly associated with maturity of the animals and with diagnosed otitis. In healthy animals, a particularly low prevalence of the genus was found in Holstein cows, especially in the summer months, a finding perhaps correlating with the open, air-exposed ears of this breed. Pendutlous-eared zebu breeds and hybrids had higher levels of colonization, although this effect was more pronounced in humid regions, and was least in the dry north and west of the state. The most common species seen was M. sympodialis, which accounted for 47.1% of isolates from healthy cattle and 39.1% from cattle with otitis. In cattle with otitis sampled in summer, we found that the relatively thermotolerant M. sympodialis made up 80.8% of isolates. By contrast, during the winter the less thermotolerant M. globosa was the most common species from otitis, making up 56% of the isolates. Humidity and temperature may be the main factors explaining the epidemiology of Malassezia diseases and colonizations in both animals and humans.

Animals↗
PubMed2002

In vitro comparison of activities of terbinafine and itraconazole against Paracoccidioides brasiliensis.

In vitro, terbinafine is highly active against a broad spectrum of pathogenic fungi. We evaluated the activities of terbinafine and itraconazole against 31 isolates of Paracoccidioides brasiliensis. The tests were conducted by using a broth macrodilution procedure. MICs, in micrograms per milliliter, were as follows: terbinafine, 0.015 to 1.0 (geometric mean, 0.1188); itraconazole, 0.007 to 0.5 (geometric mean, 0.03165). The usual therapy for paracoccidioidomycosis is sulfonamides, amphotericin B, and azole derivatives (ketoconazole, itraconazole, and fluconazole). In comparison to amphotericin B, azole derivatives allow shorter treatment courses, can be administered orally, and are equally effective. Itraconazole has as high efficacy as ketoconazole, but with superior tolerance. It is the current drug of choice for treatment of paracoccidioidomycosis. The data obtained in this study indicate that terbinafine is active against P. brasiliensis in vitro and suggest that this allylamine can be considered a new option as drug therapy for paracoccidioidomycosis.

Adult↗
PubMed2000

In vitro susceptibilities of Paracoccidioides brasiliensis yeast form to antifungal drugs.

A total of 12 Paracoccidioides brasiliensis yeast form strains, including clinical and environmental isolates, were tested for their susceptibilities to amphotericin B, ketoconazole, fluconazole, and itraconazole. The tests were determined using a broth macrodilution procedure. In general, there was a remarkable homogeneity of results for all strains, and comparable MICs were found for environmental and clinical isolates.

Antifungal Agents↗
PubMed1999

Prevalence of Malassezia spp. in the ears of asymptomatic cattle and cattle with otitis in Brazil.

Yeasts of the genus Malassezia are lipophilic microorganisms that are saprophytes that can act as opportunistic pathogens in animals. Malassezia pachydermatis is commonly isolated from the ear canal and skin of healthy dogs, or in association with seborrheic dermatitis and otitis externa conditions. The objective of the present study was to determine the occurrence of Malassezia spp. in the ears of healthy bovines and bovines with otitis. Specimens (secretion or cerumen) were collected with sterile swabs, inoculated onto Mycosel medium, supplemented with olive oil, and incubated at 35 degrees C for 1 week. Yeasts were identified according to morphological characteristics, growth in Dixon medium at 32 degrees C and Sabouraud glucose medium modified by the addition of Tween 20, 40 or 80. The results showed that 54.7% of the cultures were positive in bovines with otitis (75) and 34.6% were positive in healthy bovines (378). Analysis of the positive cultures (41) from animals with otitis allowed presumptive identification of 24 strains corresponding to M. globosa (12), M. slooffiae (5), M. furfur (5) and M. sympodialis (2). Further studies on a larger number of animals may confirm the trend verified thus far, i.e. a higher frequency of isolation of Malassezia spp. from animals with otitis than from healthy animals (P<0.01) and a predominance of the species M. globosa.

Animals↗
PubMed1988

Minnesota Multiphasic Personality Inventory-rated depression and the incidence of breast cancer.

Using data from the Walnut Creek Contraceptive Drug Study (a prospective study begun in 1969 and continuing to the present), Minnesota Multiphasic Personality Inventory-(MMPI) measured scores for depression of 8932 women were studied in relation to the incidence of breast cancer. No statistically significant association between MMPI scores for depression and the subsequent development of breast cancer was found. There was neither an association of risk of breast cancer with repression/sensitization as measured on the MMPI nor with scores on the MMPI lie scale. This study is unique because it represents the largest reported prospective cohort in which the association between depression and breast cancer development has been examined.

Adult↗