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Biomedical subjects

Stuart Brody

Publications and source records attributed to Stuart Brody.

13 recordsLinked to original sources
PubMed2003

Cognitive and psychomotor function in hypoglycemia: response error patterns and retest reliability.

Hypoglycemia has been shown to impair cognitive and psychomotor function, but it has been unclear which measures are most reliable and sensitive for detecting these effects. In a single-blind repeated measures design, healthy young adults (N=17, 8 male, mean age 27 years) performed three PC-based cognitive and psychomotor function tests: a paced auditory serial addition task (PASAT), an adaptive five-choice reaction time test (CRTT), and a manual tracking test on two occasions 4 weeks apart. In each session, a hyperinsulinemic clamp method was used during a normoglycemic (plasma glucose: 4.7 mmol/l) baseline testing period, followed in one session by a normoglycemic target testing period, and in the other session by a hypoglycemic (2.7 mmol/l) target testing period. All cognitive and psychomotor function measures showed high test-retest reliability (r ranging from.69 to.95) and sensitivity to hypoglycemia (P<.01). A new finding is that on the PASAT, hypoglycemia appears to differentially increase the rate of omission errors more than it increases false responses. Data on PASAT reaction time (RT) are also presented.

Adult↗
PubMed2003

Alexithymia is inversely associated with women's frequency of vaginal intercourse.

The study examined the relation between frequency of penile-vaginal intercourse (FSI; contrasted with other sexual behavior) and alexithymia (difficulty recognizing, identifying, and communicating emotions, reduced fantasy capacity, and an externally oriented cognitive style). To minimize response bias, persons scoring above the 86th percentile on the Eysenck Personality Inventory Lie scale were excluded. Participants (54 female and 39 male healthy young adults) completed the German version of the Toronto Alexithymia Scale (TAS-20), and provided both recall and diary measures of FSI, partner sex without vaginal intercourse, and masturbation. For women, TAS-20 scores were inversely associated with both recall and diary measures of FSI but not other sexual behavior. For men, TAS-20 scores were unrelated to all sexual behavior measures. Thus, for normal women but not men, alexithymia was specifically associated with lower FSI. Results are discussed in terms of the unique nature of penile-vaginal intercourse, emotional integration and sexuality, and both less alexithymia and greater FSI being associated with indices of better physical and psychological health.

Adult↗
PubMed2003

Circadian rhythms in Neurospora crassa: farnesol or geraniol allow expression of rhythmicity in the otherwise arrhythmic strains frq10, wc-1, and wc-2.

In Neurospora crassa, the circadian rhythm can be seen in the bd (band) strain as a series of "bands" or conidiation (spore-forming) regions on the surface of an agar medium. Certain mutations at 3 different genes (frq, wc-1, or wc-2) lead to the loss of the circadian rhythm. In this study, it was found that the addition of 10(-4) to 10(-5) M of geraniol or farnesol restored rhythmic banding to strains that lack a circadian rhythm due to mutations in any 1 of these 3 genes. These 3 conditionally arrhythmic strains now exhibited robust, free-running conidiation rhythms. Their rhythms were neither temperature-compensated nor obviously sensitive to light, so the full properties of a circadian rhythm were not restored. At 20 degrees C, in growth tubes, farnesol treatment gave periods of 28, 26, and 22 h for the frq10, wc-1, and wc-2 strains, respectively. Geraniol treatment at 20 degrees C gave periods of 23, 25.5, and 24.5 h for the frq10, wc-1, and wc-2 strains, respectively. A PRC for temperature pulses (1 h, 20 to 40 degrees C) for the frq10 strain grown in the presence of geraniol showed strong resetting (type 0), suggesting that a temperature-sensitive oscillator was present. Farnesol and geraniol are related to known intermediates in the steroid (or mevalonate) pathway. These data are interpreted in terms of a 2-oscillator model, in which farnesol/geraniol activate or amplify a remaining oscillator (a postulated frq-less oscillator).

Activity Cycles↗
PubMed2003

Assessing the role of anal intercourse in the epidemiology of AIDS in Africa.

Public health authorities have long believed that the preponderance of AIDS cases in Africa are attributable to 'heterosexual transmission'; most people silently assume this rubric to indicate penile-vaginal intercourse only. Recent epidemiologic analyses suggest that the majority of HIV cases in sub-Saharan Africa may be due to non-sterile health care practices. The present paper reviews the anthropological, proctologic, and infectious disease literature, and argues that both homosexuality and heterosexual anal intercourse are more prevalent in Africa than has traditionally been believed. The authors hypothesize that perhaps the majority of HIV transmission not accounted for by iatrogenic exposure could be accounted for by unsuspected and unreported penile-anal intercourse. Given the authors' findings, properly conducted studies to measure this HIV transmission vector, while controlling for iatrogenic exposure confound, are clearly warranted in Africa and in countries with similar epidemiologic characteristics.

Acquired Immunodeficiency Syndrome↗
PubMed2003

Let it be sexual: how health care transmission of AIDS in Africa was ignored.

The consensus among influential AIDS experts that heterosexual transmission accounts for 90% of HIV infections in African adults emerged no later than 1988. We examine evidence available through 1988, including risk measures associating HIV with sexual behaviour, health care, and socioeconomic variables, HIV in children, and risks for HIV in prostitutes and STD patients. Evidence permits the interpretation that health care exposures caused more HIV than sexual transmission. In general population studies, crude risk measures associate more than half of HIV infections in adults with health care exposures. Early studies did not resolve questions about direction of causation (between injections and HIV) and confound (between injections and STD). Preconceptions about African sexuality and a desire to maintain public trust in health care may have encouraged discounting of evidence. We urge renewed, evidence-based, investigations into the proportion of African HIV from non-sexual exposures.

Acquired Immunodeficiency Syndrome↗
PubMed2002

High-dose ascorbic acid increases intercourse frequency and improves mood: a randomized controlled clinical trial.

BACKGROUND: Ascorbic acid (AA) modulates catecholaminergic activity, decreases stress reactivity, approach anxiety and prolactin release, improves vascular function, and increases oxytocin release. These processes are relevant to sexual behavior and mood. METHODS: In this randomized double-blind, placebo-controlled 14 day trial of sustained-release AA (42 healthy young adults; 3000 mg/day Cetebe) and placebo (39 healthy young adults), subjects with partners recorded penile-vaginal intercourse (FSI), noncoital partner sex, and masturbation in daily diaries, and also completed the Beck Depression Inventory before and after the trial. RESULTS: The AA group reported greater FSI (but, as hypothesized, not other sexual behavior) frequency, an effect most prominent in subjects not cohabiting with their sexual partner, and in women. The AA but not placebo group also experienced a decrease in Beck Depression scores. CONCLUSIONS: AA appears to increase FSI, and the differential benefit to noncohabitants suggests that a central activation or disinhibition, rather than peripheral mechanism may be responsible.

Adult↗
PubMed2002

Cannabis, tobacco, and caffeine use modify the blood pressure reactivity protection of ascorbic acid.

Cannabis, caffeine, and tobacco use are associated with increased mesolimbic dopamine activity. Ascorbic acid (AA) modulates some dopaminergic agent effects, and was recently found to decrease systolic blood pressure (SBP) stress reactivity. To examine how AA SBP stress reactivity protection varies by use of these substances, data from an AA trial (Cetebe, 3000 mg/day for 14 days; N=108) were compared by substance use level regarding SBP reactivity to the anticipation and actual experience phases of a standardized psychological stressor (10 min of public speaking and arithmetic). Self-reported never users of cannabis, persons not currently smoking tobacco, and persons consuming three or more caffeine beverages daily all exhibited AA SBP stress reactivity protection to the actual stressor, but not during the anticipation phase. Conversely, self-reported ever cannabis users, current tobacco smokers, and persons consuming less than three caffeine beverages daily exhibited the AA SBP protection during the anticipation phase, but only the lower caffeine consumption group exhibited AA protection during both phases. Covariates (neuroticism, extraversion, and depression scores, age, sex, body mass index) were all nonsignificant. Results are discussed in terms of dopaminergic effects of these substances, modulation of catecholaminergic and endothelial activity, and AA support of coping styles.

Adaptation, Psychological↗
PubMed2002

Age at first intercourse is inversely related to female cortisol stress reactivity.

The relationship between age at first sexual intercourse and salivary cortisol stress reactivity (to the Trier Social Stress Test; TSST; consisting of public speaking and mental arithmetic) was examined in healthy subjects (43 females and 36 males; ages 19-38). Women reporting earlier first intercourse had less intense cortisol increases in response to the stressor (a non-significant trend was observed for males), and faster recovery from the stressor. Results were not confounded by age, oral contraceptive use, depression scores, smoking status, or body mass index. It is concluded that earlier first intercourse is associated with less reactivity to and faster recovery from stress as indexed by this endocrine measure. Results are discussed in terms of genetic and psychological influences on first intercourse and implications for coping with interpersonal stress.

Adult↗
PubMed2001

A randomized controlled trial of high dose ascorbic acid for reduction of blood pressure, cortisol, and subjective responses to psychological stress.

RATIONALE: Physiological responses to stress are considered disruptive to health. High-dose ascorbic acid has reduced indices of stress in laboratory animals. METHODS: We conducted a randomized double-blind, placebo-controlled 14-day trial of sustained-release ascorbic acid (60 healthy young adults; 3 x1000 mg/day Cetebe) and placebo (60 healthy young adults) for reduction of blood pressure, cortisol, and subjective response to acute psychological stress (Trier Social Stress Test, TSST, consisting of public speaking and mental arithmetic). Six subjects from each group were excluded. RESULTS: Compared to the placebo group, the ascorbic acid group had less systolic blood pressure (an increase of 23 versus 31 mmHg), diastolic blood pressure, and subjective stress responses to the TSST; and also had faster salivary cortisol recovery (but not smaller overall cortisol response). Cortisol response to 1 microg ACTH, and reported side-effects during the trial did not differ between groups. Plasma ascorbic acid level at the end of the trial but not pre-trial was associated with reduced stress reactivity of systolic blood pressure, diastolic blood pressure, and subjective stress, and with greater salivary cortisol recovery. CONCLUSIONS: Treatment with high-dose sustained-release ascorbic acid palliates blood pressure, cortisol, and subjective response to acute psychological stress. These effects are not attributable to modification of adrenal responsiveness.

Adult↗
PubMedDate not supplied

Concordance between women's physiological and subjective sexual arousal is associated with consistency of orgasm during intercourse but not other sexual behavior.

Many studies have found a discordance between women's genital (vaginal pulse amplitude) and subjective sexual arousal responses to erotica. We hypothesized that the association between the physiological and subjective domains would be greater for women with greater orgasmic consistency during penile-vaginal intercourse but not for orgasm consistency during other sexual behaviors. We confirmed this specific hypothesis in a sample (N = 38) of postmenopausal women. In addition, we discovered that the correlation between the domains was unrelated to social desirability responding, that orgasm consistency was not less for intercourse than for other sexual activity, and that orgasm consistency during intercourse was uncorrelated with orgasm consistency during masturbation. We discuss the results in terms of the unique nature of penile-vaginal intercourse, our study's implications for sex therapy, and orgasm consistency during intercourse being an operational measure of functional vaginal sensitivity and sexual pleasure integration and organization.

Arousal↗