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Biomedical subjects

J Rinaldi

Publications and source records attributed to J Rinaldi.

15 recordsLinked to original sources
PubMed2003

Availability of combination therapy for HIV: effects on sexual risk taking in a sample of high-risk gay and bisexual men.

The objective of this study was to assess the impact of successes in the medical treatment of HIV disease on the perceptions of high-risk gay and bisexual men attending an anonymous testing site towards becoming infected with HIV and on their decisions to have unsafe sex. A cross-sectional survey with a face-to-face interview and self-recorded information was used. A convenience sample of high-risk men seeking anonymous HIV antibody counselling was recruited for an intervention study. To be eligible, men had to have a history of at least one previous negative antibody test and unprotected anal intercourse within the last year. Upon enrollment, subjects were asked about the impact of new treatment developments on their decisions to engage in high-risk sex both in the recent past and in the future. In general, neither the recent successes in treating HIV nor the availability of combination therapy had any impact on the men's decisions about safe sex, although a minority of men reported less concern about becoming HIV-positive. Also, some men reported already having taken more risk. In conclusion, a small number of men in this high-risk population have increased risk behaviour as a result of recent treatment advances. These results merit continued monitoring.

Adult↗
PubMed1999

Frontal brain electrical activity in infants of depressed and nondepressed mothers: relation to variations in infant behavior.

In previous studies, infants of depressed mothers have been found to exhibit reduced left frontal brain electrical activity (EEG). The left frontal region has been hypothesized to mediate social approach behaviors and positive affective expression. These findings raise important questions about the cause and nature of atypical EEG patterns in infants of depressed mothers. The present study begins to address some of these questions by examining whether or not variations in patterns of frontal brain activity in infants of depressed and nondepressed mothers are related to variations in infant behavior as observed in naturalistic situations. If such relations exist, are they specific to certain behaviors hypothesized to be mediated by the frontal region (i.e., positive approach behaviors)? Frontal and parietal brain electrical activity was recorded from 14- to 15-month old infants of depressed versus nondepressed mothers during a baseline condition and during conditions designed to elicit interest and positive affect. Infant behavior was observed in naturalistic play conditions, with and without mother, on a separate day from EEG testing. Mothers provided information on infant temperament. Infants of depressed mothers showed less affection and touching of their mothers. For infants of depressed mothers only, reduced left frontal brain activity was found to be related to lower levels of affection toward mother, but not to infant temperament. Furthermore, increased generalized frontal activation was found to be related to higher levels of negative affect, hostility, and tantrums and aggression. Relations between infant brain activity and behavior were not found for parietal EEG activity. These results suggest that infant frontal electrical brain activity is related to variations in infant behavior, especially those involved in positive affiliative behavior and the expression and regulation of negative affect. The nature and cause of atypical patterns of brain activity and question of whether such atypical patterns of frontal brain activity predispose infants to affective disorders in later life are discussed.

Depression↗
PubMed1999

Name-based reporting of HIV-positive test results as a deterrent to testing.

OBJECTIVES: This study evaluated attitudes toward name-based reporting of HIV. METHODS: One hundred thirty high-risk, male repeat testers received information on the public health benefits of name-based reporting and reported their intentions to test. RESULTS: Of the 67 men who were randomly selected and asked their intentions before hearing the benefits, 63% said they would not test if reporting were required. After hearing the benefits, 19% changed their minds (P < .014). Of the 63 men who were asked only after hearing the benefits, 44% would not test. CONCLUSIONS: Implementing name-based reporting without working before-hand to change attitudes could undermine the benefits of both testing and HIV surveillance.

AIDS Serodiagnosis↗
PubMed1998

Children with autism fail to orient to naturally occurring social stimuli.

Children with autism were compared to developmentally matched children with Down syndrome or typical development in terms of their ability to visually orient to two social stimuli (name called, hands clapping) and two nonsocial stimuli (rattle, musical jack-in-the-box), and in terms of their ability to share attention (following another's gaze or point). It was found that, compared to children with Down syndrome or typical development, children with autism more frequently failed to orient to all stimuli, and that this failure was much more extreme for social stimuli. Children with autism who oriented to social stimuli took longer to do so compared to the other two groups of children. Children with autism also exhibited impairments in shared attention. Moreover, for both children with autism and Down syndrome, correlational analyses revealed a relation between shared attention performance and the ability to orient to social stimuli, but no relation between shared attention performance and the ability to orient to nonsocial stimuli. Results suggest that social orienting impairments may contribute to difficulties in shared attention found in autism.

Attention↗
PubMed1998

Folate, vitamin B12, homocysteine status and DNA damage in young Australian adults.

We performed a cross-sectional study (n = 49 males, 57 females) and a randomized double-blind placebo-controlled dietary intervention study (n = 31/32 per group) to determine the effect of folate and vitamin B12 (B12) on DNA damage (micronucleus formation and DNA methylation) and plasma homocysteine (HC) in young Australian adults aged 18-32 years. None of the volunteers were folate deficient (i.e. red blood cell folate <136 nmol/l) and only 4.4% (all females) were vitamin B12 deficient (i.e. serum vitamin B12 <150 pmol/l). The cross-sectional study showed that (i) the frequency of micronucleated cells (MNCs) was positively correlated with plasma HC in males (R = 0.293, P < 0.05) and (ii) in females MNC frequency was negatively correlated with serum vitamin B12 (R = -0.359, P < 0.01) but (iii) there was no significant correlation between micronucleus index and folate status. The results also showed that the level of unmethylated CpG (DNA) was not significantly related to vitamin B12 or folate status. The dietary intervention involved supplementation with 3.5x the recommended dietary intake (RDI) of folate and vitamin B12 in wheat bran cereal for three months followed by ten times the RDI of these vitamins via tablets for a further three months. In the supplemented group, MNC frequency was significantly reduced during the intervention by 25.4% in those subjects with initial MNC frequency in the high 50th percentile but there was no change in those subjects in the low 50th percentile for initial MNC frequency. The reduction in MNC frequency was significantly correlated with serum vitamin B12 (R = -0.49, P < 0.0005) and plasma HC (R = 0.39, P < 0.006), but was not significantly related to red blood cell folate. DNA methylation status was not altered in the supplemented group. The greatest decrease in plasma HC (by 37%) during the intervention was observed in those subjects in the supplemented group with initial plasma HC in the high 50th percentile, and correlated significantly with increases in red blood cell folate (R = -0.64, P < 0.0001) but not with serum vitamin B12. The results from this study suggest that (i) MNC frequency is minimized when plasma HC is below 7.5 micromol/l and serum vitamin B12 is above 300 pmol/l and (ii) dietary supplement intake of 700 microg folic acid and 7 microg vitamin B12 is sufficient to minimize MNC frequency and plasma HC. Thus, it appears that elevated plasma HC, a risk factor for cardiovascular disease, may also be a risk factor for chromosome damage.

Adult↗
PubMed1998

Neuropsychological correlates of early symptoms of autism.

Both the medial temporal lobe and dorsolateral prefrontal cortex have been implicated in autism. In the present study, performance on two neuropsychological tasks--one tapping the medial temporal lobe and related limbic structures, and another tapping the dorsolateral prefrontal cortex--was examined in relation to performance on tasks assessing autistic symptoms in young children with autism, and developmentally matched groups of children with Down syndrome or typical development. Autistic symptoms included orienting to social stimuli, immediate and deferred motor imitation, shared attention, responses to emotional stimuli, and symbolic play. Compared with children with Down syndrome and typically developing children, children with autism performed significantly worse on both the medial temporal lobe and dorsolateral prefrontal tasks, and on tasks assessing symptoms domains. For children with autism, the severity of autistic symptoms was strongly and consistently correlated with performance on the medial temporal lobe task, but not the dorsolateral prefrontal task. The hypothesis that autism is related to dysfunction of the medial temporal lobe and related limbic structures, such as the orbital prefrontal cortex, is discussed.

Age Factors↗
PubMed1995

A comparison of lymphocyte micronuclei and plasma micronutrients in vegetarians and non-vegetarians.

We performed a biochemical and cytogenetic epidemiological study to establish if there are significant differences between vegetarians (V) and non-vegetarians (NV) in their peripheral blood lymphocyte micronucleus (MN) index, which is a measure of chromosome damage rate. The levels of plasma vitamin C (VIT-C), vitamin E (VIT-E), vitamin B12 (B12) and folic acid were also analysed to assess if differences in chromosome damage rates were associated with these potentially antimutagenic micronutrients. Volunteers were classified as either 'vegetarian' if they had abstained from eating any flesh foods for at least 3 years prior to the study or 'non-vegetarian' if they consumed meat or meat products at least 5 days/week for at least 3 years before participation in the study. The volunteers in the study consisted of 47 male and 79 female V and 66 male and 72 female NV, all of whom were non-smokers for at least 3 years prior to the study. The age of the volunteers varied between 20 and 89 years. There was no significant difference in the slope of the age-related increase in MN index of V and NV of either sex. However, the MN index was significantly lower in NV males in the age group 20-40 years and significantly lower for V males in the 41-60 years age group. No difference between the MN index of older males was detectable and there also was no difference in the MN index of V and NV females across all age groups. V were generally found to have significantly higher plasma levels of VIT-C and folic acid, significantly lower levels of B12, and similar levels of VIT-E when compared with NV. VIT-C correlated positively with MN index in young males, but the reverse was true for B12. In young females folate and B12 appeared to correlate negatively with MN index. VIT-E had no apparent impact on MN index. These data suggest that the level of folate and B12 may be more important than VIT-C or VIT-E in minimizing chromosome damage rates in human lymphocytes. Overall, the data from this study do not support the hypothesis that V have a lower genetic damage rate than NV.

Adult↗
PubMed1994

The relationship between micronuclei in human lymphocytes and plasma levels of vitamin C, vitamin E, vitamin B12 and folic acid.

The cytokinesis-block micronucleus assay is increasingly being applied to the study of spontaneous or induced genetic damage in human lymphocytes, but little is known about dietary and other lifestyle factors that could influence this index. As part of a larger study investigating the role of dietary factors on baseline genetic damage in human lymphocytes from 152 non-smoking females and 113 non-smoking males evenly distributed between the ages of 20 and 87 years, we have measured (a) the micronucleus (MN) frequency and (b) the plasma level of the anti-oxidant vitamins C and E and the B vitamins folic acid and B12. Multiple regression analysis indicated that age (beta value = 0.598, P < 0.0001) was the most important factor influencing the variance of micronucleus frequency in females, while micronutrient levels had no apparent significant effects on genetic damage. In males age was also the predominant factor (beta value = 0.505, P < 0.0001) influencing genetic damage, but vitamin-C level also contributed positively and significantly to the observed MN frequency (beta value = 0.220, P < 0.0228). To avoid the potential confounding effect of collinearity between variables we also performed separate simple regression analysis for each plasma micronutrient in relation to age-adjusted micronucleus frequency; the results from this analysis again showed a significant and positive effect of plasma vitamin C on age-adjusted micronucleus frequency in males only (beta value = 0.188, P = 0.0503), while no effect was observed for the other micronutrients in both sexes. In view of the predominant age effect, we also focused on the data obtained in the youngest age groups of both sexes. In view of the predominant age effect, we also focused on the data obtained in the youngest age groups of both sexes (i.e. 20-30 years olds) and found (a) that the MN frequency in young males is significantly and positively correlated with plasma vitamin C levels (r = 0.823, P < 0.001) but negatively correlated with plasma vitamin B12 status (r = -0.799, P < 0.001) and (b) in females the only significant correlation was an inverse relationship between MN frequency and the combined folate and vitamin B12 plasma levels (r = -0.4632, P < 0.030).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1994

The origin of micronuclei induced by cytosine arabinoside and its synergistic interaction with hydroxyurea in human lymphocytes.

Using human lymphocytes and the cytokinesis-block micronucleus (CBMN) assay we have recently shown that excision-repairable DNA lesions induced by methylnitrosourea (MNU) and ultraviolet (UV) light (254 nm) can be converted to micronuclei (MNi) within one cell cycle if cytosine arabinoside (ARA-C) is added during the G1 phase of the cell cycle after mitogen stimulation. We have proposed that this conversion resulted from the inhibition by ARA-C of the gap-filling step during excision repair which results in the formation of single-stranded breaks at repair sites; these breaks are then converted to chromatid or chromosome breaks and subsequently to MNi on completion of nuclear division. To confirm this hypothesis we have examined the origin of MNi induced by ARA-C by using anti-kinetochore antibodies and found that between 77 and 86% of these MNi are kinetochore-negative which supports the idea that they originate mainly from acentric chromosome fragments. We have also demonstrated that combining ARA-C treatment with hydroxyurea (HU) during G1 provides a synergistic improvement in the conversion of spontaneous (4-fold increment) or MNU-induced (2-fold increment) excision-repairable DNA lesions to MNi when compared to the effects with ARA-C alone. HU treatment on its own did not influence micronucleus expression in untreated cells and cells treated with MNU.

Adult↗
PubMed1990

Evaluation of a hospital based substance abuse intervention and referral service for HIV affected patients.

This paper reports an outcome evaluation and needs assessment conducted by the AIDS and Substance Abuse Program (ASAP) of the San Francisco AIDS Health Project. The study was designed to: 1) evaluate effectiveness of a hospital based intervention and referral service for HIV affected substance abusers, and 2) gather information from this population regarding accessibility and barriers to drug treatment. Participants were 86 individuals consecutively referred to ASAP over an 8-month period. All received a brief needs assessment interview in addition to the standard ASAP evaluation protocol. Agency follow-up contacts were made for those individuals referred by ASAP to extended substance abuse treatment, with information limited to whether or not the client contacted the designated referral resource. Source of referral to ASAP, interest in treatment, and prior sexual risk behavior change were significant predictors of intervention outcome. Personal unreadiness and treatment program waiting lists were the most frequently reported obstacles to treatment. While most participants reported changing risk behavior in response to the AIDS epidemic, patterns of change differed according to intravenous drug use history.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Sex is an important variable affecting spontaneous micronucleus frequency in cytokinesis-blocked lymphocytes.

The micronucleus frequency in cytokinesis-blocked lymphocytes of 152 females and 113 males aged between 20 and 89 years (minimum of 15 subjects per sex per decade) was compared. Marked differences in the micronucleus frequency of males and females were observed: (a) there was a greater dispersion in the results for females when compared to males in all age groups older than 40 years; (b) there was a significant positive correlation between micronucleus frequency and age in both sexes (p < 0.0001) but the slope of the linear regression line was steeper in females (slope = 0.499 micronuclei/year) compared to males (slope = 0.289 micronuclei/year) (p < 0.0045); (c) the micronucleus frequency in females (Mf) was significantly higher than the micronucleus frequency in males (Mm) in all decades examined (p < 0.05), the Mf,Mm ratio varied between 1.47 and 1.65 (mean +/- 1 SEM = 1.53 +/- 0.03) and showed no trend with age. These results suggest that an added mechanism, possibly the loss of X chromosomes, is contributing to the micronucleus frequency in females and highlights the importance of sex as a variable that has to be taken into consideration when interpreting data from cross-sectional studies utilising the cytokinesis-block micronucleus assay as a biomarker of chromosome damage.

Adult↗