TASK DEFINITION: Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.
PROBLEM: Abstract: Tissue available (bioavailable) testosterone (T) includes circulating free T (FT) and albumin-bound T. A reasonable assessment of bioavailable T can be made by using 50% ammonium sulfate to precipitate sex hormone-binding globulin (SHBG)-bound T. The supernatant non-SHBG-bound T (non-SHBG-T) correlates well with physiological androgen activity. To assess bioavailable T in normal aging men, we analyzed serum samples from seven healthy aged men (65-83 yr old) and compared the results to samples from 13 young men (22-39 yr old). Mean serum T, FT, and LH concentrations were not significantly different in the 2 groups. However, the mean absolute non-SHBG-T level was significantly lower (P less than 0.005) in the older group. In a separate population of 20 impotent but otherwise healthy men (5 27-37 yr old, 10 48-64 yr old, and 5 66-69 yr old), the mean absolute non-SHBG-T concentration was lower in middle-aged (P less than .01) and elderly men (P less than 0.001) than in young men. The absolute FT was lower only in the elderly group (P less than 0.05), while mean LH and T levels were similar in all 3 age groups. These data suggest that serum concentrations of tissue available T are decreased in aged men and that non-SHBG-T measurement is a more sensitive indicator of this decrease than are serum T or serum FT measurements. These changes appear to begin by middle age.

SOLUTION: Decreased bioavailable testosterone in aging normal and impotent men.

PROBLEM: Abstract: VEPs were recorded with three different spatial frequencies of stimulation in patients affected by idiopathic Parkinsonism and by Parkinsonian syndromes. The detection of VEP abnormalities in Parkinson's disease was dependent on the spatial frequency of the visual stimulus (a vertical square wave grating). The VEP latency was normal in Parkinsonian syndrome patients (except in one patient affected by familial Parkinsonism). Dopamine precursor therapy differently reduced the VEP latency, depending on the spatial frequency of the visual stimulus. These findings suggest that the dopaminergic mechanism involved in the generation of VEP delays is sensitive to stimulus spatial frequency. The study of VEPs before and after the administration of haloperidol confirmed this hypothesis. VEP latency did not correlate with the major clinical symptoms of Parkinson's disease and could not predict the results of chronic dopaminergic therapy.

SOLUTION: Visual evoked potentials in parkinsonism and dopamine blockade reveal a stimulus-dependent dopamine function in humans.

PROBLEM: Abstract: Vasoactive intestinal peptide (VIP) has been proposed as an inducer of PRL release. Moreover, immunocytochemical studies suggested an increase in the VIP content in the hypothalamus of lactating rats. We investigated whether this increase is regulated at the level of gene transcription. A sensitive RNA detection assay that uses in vitro transcribed RNA probes corresponding to specific exons of the VIP gene was devised to study VIP gene expression. Using this method, an approximately 2000-base long RNA containing the coding sequences for VIP was detected in rat hypothalamus. This RNA also contains the coding sequences for the VIP-related peptide PHM/I (peptide histidine methionine amide or isoleucine amide). An identical VIP-encoding RNA was previously identified in the rat cerebral cortex. A 2-fold increase was observed in hypothalamic VIP mRNA during lactation. In addition, the levels of this mRNA increased in the hypothalamus at the time of sexual maturation. Taken together, our results suggest a physiological regulation of VIP gene expression associated with its potential role as a neuroendocrine hormone.

SOLUTION:
Hypothalamic vasoactive intestinal peptide messenger ribonucleic acid is increased in lactating rats.