Table of Contents

Abstract: Geological substrates and air pollution affect the availability of calcium to mammals in many habitats, including the Adirondack Mountain Region (Adirondacks) of the United States. Mammalian insectivores, such as shrews, may be particularly restricted in environments with low calcium. We examined the consequences of calcium restriction on the least shrew (Cryptotis parva) in the laboratory. We maintained one group of shrews (5 F, 5 M) on a mealworm diet with a calcium concentration comparable to beetle larvae collected in the Adirondacks (1.1 ± 0.3 mg/g) and another group (5 F, 3 M) on a mealworm diet with a calcium concentration almost 20 times higher (19.5 ± 5.1 mg/g). Animals were given no access to mineral sources of calcium, such as snail shell or bone. We measured running speed and performance in a complex maze over 10 weeks. Shrews on the high-calcium diet made fewer errors in the maze than shrews on the low-calcium diet (F_1,14 = 12.8, p < 0.01). Females made fewer errors than males (F_1,14 = 10.6, p < 0.01). Running speeds did not markedly vary between diet groups or sexes, though there was a trend toward faster running by shrews on the high calcium diet (p = 0.087). Shrews in calcium-poor habitats with low availability of mineral sources of calcium may have greater difficulty with cognitive tasks such as navigation and recovery of food hoards.

Abstract: Youth homelessness is a growing problem in the United States. The experience of homelessness appears to have numerous adverse consequences, including psychiatric and substance use disorders. This study compared the frequencies of psychiatric disorders, including substance use, between homeless youth (18–24 years-old) in San Francisco (N = 31) and Chicago (N = 56). Subjects were administered the Mini International Neuropsychiatric Interview (M.I.N.I.) to assess DSM-IV-TR diagnoses and substance use disorders. Eighty-seven percent of the San Francisco youth, and 81% of the Chicago youth met criteria for at least one M.I.N.I. psychiatric diagnosis. Nearly two-thirds of the youth in both samples met criteria for a mood disorder. Approximately one-third met criteria for an anxiety disorder. Thirty-two percent of the San Francisco sample and 18% of the Chicago met criteria for Antisocial Personality Disorder. Approximately 84% of the San Francisco youth and 48% of the Chicago youth met criteria for a substance-related disorder, and more substances were used by San Francisco youth. In conclusion, the high rate of psychiatric disorders in homeless youth provides clear evidence that the mental health needs of this population are significant. Implications are discussed.

Abstract: The androgenic adrenal steroids dehydroepiandrosterone (DHEA) and 4α-androstenedione (4-A) have significant biological activity, but it is unclear if the behavioral effects are unique or only reflections of the effects of testosterone (TS). Gonadally intact male Long-Evans rats were assigned to groups to receive supplements of DHEA, 4-A, TS, corticosteroid (CORT), all at 400 µg steroid/kg of body weight, or vehicle only for 5 weeks. All males were tested in a paradigm for sexual motivation that measures time and urinary marks near an inaccessible receptive female. It was found that DHEA and 4-A supplements failed to influence time near the estrous female in the same way TS supplements did, and, indeed, 5 weeks of 4-A administration reduced the time similar to the suppressive effects of CORT after 3 weeks. Further, animals treated with DHEA or 4-A left fewer urinary marks near an estrous female than TS and control groups. These results suggest that DHEA and 4-A are not merely precursors of sex hormones, and provide support for these steroids influencing the brain and behavior in a unique fashion that is dissimilar from the effects of TS on male sexual behavior.