The effects of illicit drug use and HIV infection on sex hormone levels in women.

Drug use and HIV infection may affect sex hormone levels in women. One hundred and ninety-six women with and without a history of illicit drug use (50 HIV-negative and 148 HIV-infected), with regular menses, who never used antiretrovirals, were evaluated. Luteinizing hormone levels were significantly higher in women with a CD4 cell count <200/microl (p < 0.002). Current methadone use was associated with lower levels of total testosterone (p = 0.03) and higher levels of prolactin (p = 0.002); mean estradiol levels were 43% lower in women who used intravenous drugs (p < 0.001). Alcohol and crack cocaine use was not associated with sex hormone levels. Age, race, body mass index and degree of HIV immunosuppression were also associated with differences in sex hormone levels.     

Color vision and dentistry.

Color vision is a critical component of restorative and esthetic dentistry, but dentists, as a group, do not have their color vision tested at any time during their careers. A study was undertaken to ascertain the color-vision status of practicing dental personnel at the University of Tennessee, College of Dentistry. One hundred fifty individuals, 75 men and 75 women, were screened. The results corroborated the existing medical data for the general population. It was found that 9.3% of the men and none of the women exhibited color-vision defect. Since most dentists are male, this study demonstrates an area of potential weakness for some practitioners. Once a color-vision problem is found, it is simple to remedy by employing a team approach to shade matching or mechanical means of matching shades (by the practitioner). No ethnic or racial distinctions were detected, although these have been reported in other studies.     

Long-range temporal correlations in the spontaneous spiking of neurons in the hippocampal-amygdala complex of humans

The spontaneous or background discharge patterns of in vivo single neuron is mostly considered as neuronal noise, which is assumed to be devoid of any correlation between successive inter-spike-intervals (ISI). Such random fluctuations are modeled only statistically by stochastic point process, lacking any temporal correlation. In this study, we have investigated the nature of spontaneous irregular fluctuations of single neurons from human hippocampus-amygdala complex by three different methods: (i) detrended fluctuation analysis (DFA), (ii) multiscale entropy (MSE), (iii) rate estimate convergence. Both the DFA and MSE analysis showed the presence of long-range power-law correlation over time in the ISI sequences. Moreover, we observed that the individual spike trains presented non-random structure on longer time-scales and showed slow convergence of rate estimates with increasing counting time. This power-law correlation and the slow convergence of statistical moments were eliminated by randomly shuffling the ISIs even though the distributions of ISIs were preserved. Thus the power-law relationship arose from long-term correlations among ISIs that were destroyed by shuffling the data. Further, we found that neurons which showed long-range correlations also showed statistically significant correlated firing as measured by correlation coefficient or mutual information function. The presence of long-range correlations indicates the history-effect or memory in the firing pattern by the associative formation of a neuronal assembly.     

Differential Effects of Left versus Right Monaural Biofeedback for Heart Rate Increase

Cerebral lateralization in the voluntary increase of heart rate was investigated in a biofeedback experiment involving 20 right-handed female subjects randomly assigned to one of two groups: right or left ear input of stimulus and biofeedback information. The stimulus was a 1000 Hz tone which signalled the start and duration of 30 20-sec training trials. Feedback was a click presented every time an interbeat interval was shorter than a criterion established through a shaping schedule. A monetary bonus provided additional reinforcement at the end of each trial. Subjects given right ear feedback increased their heart rate significantly more than subjects given left ear feedback. The largest difference between the group means (7 bpm) was recorded after the first 20 training trials. The results are discussed in terms of hemispheric perceptual and functional differences.     

Sweets, chocolate, and atypical depressive traits

An original questionnaire, the Foods and Moods Inventory (FMI) was used to investigate appetite for sweets and chocolate and its relationship to dysphoric mood. The FMI was administered to a group of subjects with an identified interest in chocolate (chocolate group, N = 73), a comparison sample (comparison group, N = 172), and a sample of former alcoholics (N = 22). Those who reported "self-medicating" with sweets or chocolate were more likely to have personality traits associated with hysteroid dysphoria, an atypical depressive syndrome. In addition, the tendency to eat compulsively, in general, and appetite for sweets and chocolate, in particular, were significantly greater among women.