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Biomedical subjects

M C Dufour

Publications and source records attributed to M C Dufour.

At least 19 recordsLinked to original sources
PubMed2001

Transient post-mating inhibition of behavioural and central nervous responses to sex pheromone in an insect.

Mating is costly for both male and female insects and should therefore only occur if it is likely to be successful. Within one scotophase, which is the dark period of the light cycle, male moths can only produce one single spermatophore, which is transferred to the female during mating. Remating within the same scotophase would thus be unsuccessful. We tested the hypothesis that newly mated males of the moth Agrotis ipsilon have developed an energy-saving strategy based on the transient inhibition of their sexual behaviour, thus avoiding unsuccessful remating. Agrotis ipsilon males do not copulate more than once during the same scotophase. Moreover, newly mated males do not respond behaviourally to the female sex pheromone although electroantennograms showed that their peripheral olfactory system is fully functional. However, intracellular recordings of antennal lobe neurons showed that the sensitivity for the synthetic sex pheromone blend decreased as compared with that of unmated males. Both the sexual behaviour and the sensitivity of the antennal lobe neurons were restored when tested during the next scotophase. Our results show a fast, transient neuronal plasticity that 'switches off' the olfactory system, which could prevent males from mating unsuccessfully.

Animals↗
PubMed2001

The relationship of early-onset regular smoking to alcohol use, depression, illicit drug use, and other risky behaviors during early adolescence: results from the youth supplement to the third national health and nutrition examination survey.

PURPOSE: Recently we found that the early onset of regular tobacco use is as predictive of lifetime drug use and depressive disorders as it is of alcohol use disorders [Alcohol.: Clin. Exp. Res. 23 (1999) 513.]. This finding, which paralleled findings regarding early onset of alcohol use [J. Subst. Abuse 10 (1998) 59.], suggested that early regular use of any drug might simply be an indicator of risk for a constellation of problem behaviors. The purpose of the present study is to test this hypothesis as well as to study the strength and patterns of associations among these problem behaviors already present among youth. The results will permit description of more precise profiles to identify groups of children at risk. METHODS: Using data for respondents aged 12-16 from the Third National Health and Nutrition Examination Survey (NHANES III), descriptive statistics were calculated and logistic regression models were estimated. RESULTS: Descriptive analyses indicated that in comparison with those who never smoked, or who simply experimented, early-onset regular smokers, both those who began at age 13 or younger and those who did so between 14 and 16, were those most likely to use alcohol and other drugs as well as have school problems and early sexual experiences culminating in pregnancy. Multivariate logistic regression analyses were conducted to assess the associations among these high-risk behaviors. IMPLICATIONS: These results support the hypothesis that early onset of smoking is but an indicator of a syndrome of problem behaviors already in place during childhood. They also suggest that the significance of an age onset variable may differ depending on the age of the sample used. As follow-up data are collected, we expect to learn much about the natural course of the distinct risk groups identified in the analyses by studying longitudinally this nationally representative group of early adolescents.

Adaptation, Psychological↗
PubMed2001

If you drink alcoholic beverages do so in moderation: what does this mean?

The changes in content of the alcohol guideline of the various editions of the Dietary Guidelines for Americans from 1980 to 2000 are discussed. This is followed by a capsule summary of the history and evolution of the discipline of alcohol epidemiology compared with that of nutrition epidemiology. Methods of assessment are discussed, and issues surrounding the validity and reliability of self-report of alcohol consumption are then outlined. Relevant objectives from Healthy People 2010 are discussed. Surveillance of the alcohol guideline discloses that, at present, very few American drinkers follow the recommendations of the alcohol guideline. Indications for future research needs to address this issue conclude the discussion.

Alcohol Drinking↗
PubMed2001

The critical dimension of ethnicity in liver cirrhosis mortality statistics.

BACKGROUND: In 1997, liver cirrhosis was the 10th leading cause of death in the United States. Beginning in the 1950s, liver cirrhosis mortality rates have been consistently higher for black than for white men and women. There has been a gradual adoption of the recommendation that all death certificates include information on the Hispanic origin of decedents, with universal adoption in the 1997 data year. It is the purpose of this study to examine the extent to which relative risks for cirrhosis mortality might shift for different demographic groups when Hispanic origin is considered along with the race and sex of the decedent. METHODS: Age-adjusted death rates were calculated for liver cirrhosis by using public-use data files produced by the National Center for Health Statistics. Trends in cirrhosis mortality rates from 1991 through 1997 are shown for white Hispanic, white non-Hispanic, black Hispanic, and black non-Hispanic men and women. RESULTS: In 1997, white Hispanic men show the highest cirrhosis mortality rates over the period examined, followed by black non-Hispanic and white non-Hispanic men, white Hispanic women, and black non-Hispanic and white non-Hispanic women. Among Hispanic decedents, the largest group was of Mexican ancestry, with large numbers being born outside the United States and having low education levels. CONCLUSIONS: The findings of higher risk for cirrhosis mortality among white men and women of Hispanic origin serve to focus new attention on these demographic groups. Collateral analyses of other causes of death do not support alternate explanations of these findings as artifacts of demographic misclassification. Future studies of amounts and patterns of alcohol consumption should include Hispanic origin among demographic factors examined.

Black or African American↗
PubMed1999

What is moderate drinking? Defining "drinks" and drinking levels.

Although the benefits and risks associated with moderate drinking have gained increasing attention in recent years from both researchers and the general public, no universal definition of moderate drinking exists. Most currently used definitions are based on a certain number of drinks consumed in a specific time period. Defining a "drink," however, also is difficult because alcoholic beverages can differ substantially in their alcohol content, even within the same beverage category (e.g., beer, wine, or distilled spirits). Because international differences in drink definitions also exist, comparing studies from different countries is difficult. The development of a universal definition of moderate drinking is hampered further by variations in the way alcohol consumption levels and drinking patterns are being assessed (i.e., the survey methods and assessment modes used). Despite these problems, definitions of moderate drinking and drinking guidelines have been developed in the United States and other countries.

Alcohol Drinking↗
PubMed1998

The pheromone biosynthesis activating neuropeptide (PBAN) of the black cutworm moth, Agrotis ipsilon: immunohistochemistry, molecular characterization and bioassay of its peptide sequence.

PBAN-like immunoreactivity has been detected in the suboesophageal ganglion and the brain (Br-SOG) of larvae and adult males and females of Agrotis ipsilon, using an antiserum against Helicoverpa zea PBAN (Hez-PBAN). The amino acid sequence of A. ipsilon PBAN (Agi-PBAN) was deduced from the cDNA sequence, using both Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) and 5' Rapid Amplification of cDNA Ends (RACE). The primers were degenerate sets of oligonucleotides derived from known amino acid sequences of the PBAN precursor. The final cloned fragment contained the complete DNA sequence coding for the putative Agi-PBAN. Based on a comparison with known PBAN processing from the polypeptide precursor, we propose that Agi-PBAN is a 33-amino acid peptide. Agi-PBAN exhibits high sequence homology with Hez-PBAN (88%), Lymantria dispar PBAN (Lyd-PBAN, 88%) and Bombyx mori PBAN (Bom-PBAN, 73%). Agi-PBAN shares the C-terminal hexapeptide sequence (Tyr-Phe-Ser-Pro-Arg-LeuNH2) with all identified PBANs but has only one methionine residue instead of two in Hez-PBAN and Lyd-PBAN, and three in Bom-PBAN. Based on predicted a.a. sequence, Agi-PBAN, with Leu-NH2 as C-terminal motif, has been synthesized and assayed for its ability to promote pheromone production in decapitated females of A. ipsilon. Synthetic Agi-PBAN induced pheromone production in decapitated females as evaluated by the male responsiveness to the pheromonal blend in a wind tunnel.

Amino Acid Sequence↗
PubMed1997

The effects of substance use during gestation on birth outcome, infant and maternal health.

This study examines the relationship of substance use to birth outcome, infant, and maternal health in a large, nationally representative sample. Multiple regression analyses, accommodating the nature of the survey data using the SUDAAN software package, indicated that drinking and smoking independently and/or interactively with depression account for poor health and serious medical conditions among pregnant women as well as negative birth outcomes or adverse health consequences in those infants who are live births. In addition, African American women and their infants are more likely than those of other racial groups to suffer these adverse outcomes. Given the risk profiles of individual illnesses, this study suggests the need for developing and targeting health education and preventive efforts specific to those groups that are clearly at greater risk.

Alcohol Drinking↗
PubMed1995

Alcohol use in combination with cocaine, heroin and methadone by medical examiner cases.

OBJECTIVE: The purpose of this review of all appropriate, available medical examiner (ME) studies is to provide information on cases with positive toxicologies for cocaine, morphine (the heroin metabolite) and methadone that have positive blood or brain alcohol concentrations (BACs). METHODS: Criteria for inclusion of U.S. ME studies in this review are (1) at least 20 cases with a positive toxicology for cocaine, morphine or methadone and (2) BAC test findings according to specific drug positivity. Only 19 studies conducted from 1969 to 1992 met these criteria; most studies reviewed were not included primarily because of their failure to present or link available BAC test findings with positive toxicologies for these other drugs. RESULTS: The BAC-positive ranges were similar for cocaine and heroin. In reports on both heroin and methadone or on all three drugs, heroin-positive cases had the highest proportions and methadone-positive cases had the lowest proportions with positive BACs. CONCLUSIONS: Published data confirm the substantial presence of alcohol in combination with cocaine, heroin and methadone among ME cases. Future ME studies should endeavor to link BAC and toxicology findings for other drugs according to drug-induced or drug-related manner of death. These data would advance our knowledge about the role of alcohol in drug deaths and provide additional information on substance abuse trends.

Adolescent↗
PubMed1994

The motivational correlates of drinking, smoking, and illicit drug use during pregnancy.

Despite attempts to eliminate the consumption of alcohol, tobacco, and other substances of abuse by women of childbearing age, especially during gestation, apparently many do not curtail these negative lifestyle behaviors, as evidenced by the number of poor birth outcomes and developmentally disabled children born each year. This study examined the relationship of depression, attitude toward pregnancy, a number of sociodemographic variables, and substance use by women of child-bearing age prior to and after learning of their pregnancies. Results indicated that attitude independently, and depression independently and in interaction with socio-demographic factors are associated with substance use at both time points. From this we conclude that preventive efforts should be designed and targeted at those women who are depressed, especially those who have the sociodemographic characteristics associated with heavier substance use.

Adolescent↗
PubMed1994

Direct assessment of the rate of chromosomal abnormalities in grade IV human embryos produced by in-vitro fertilization procedure.

During in-vitro fertilization (IVF) procedures, human preimplantation embryos were classified into four grades according to their morphological appearance under light microscopy. The grade IV group included poor quality embryos. In our IVF programme, these embryos were never transferred or frozen, and were thus available for cytogenetic analysis. Cytogenetic analysis was performed on 411 grade IV embryos from 327 couples participating in the IVF programme. A total of 118 embryos were successfully karyotyped using at least one metaphase. Normal diploid chromosomes were found in only 12 embryos, containing a total of 19 metaphases. All others (90%) showed abnormal or aberrant chromosome complements; 48 were aneuploid and six cases of single chromatids were noted; 14 embryos (11.8%) contained haploid complements, while the remaining 44 exhibited mosaics (2n/3n, n/2n, n/3n) or fragmented chromosome sets. Also, several structural aberrations and rearrangements were observed. These results indicate that the large majority of grade IV human embryos are chromosomally abnormal. This confirms the morphological assessment of the poor quality of these embryos and demonstrates the uselessness of both the transfer and the cryopreservation of grade IV embryos.

Blastocyst↗
PubMed1994

Relationship between age and drinking patterns and drinking problems among Japanese, Japanese-Americans, and Caucasians.

Comparing alcohol consumption patterns by age and gender among Japanese in Japan and Japanese-Americans and Caucasians in the United States, this study examined the associations between age and both heavy drinking and social problems using logistic regression for each ethnic group of male current drinkers. As reported in previous studies of Caucasians, men drink more alcohol than women, older respondents are more likely than younger ones to be abstainers, and the percentages of heavier drinkers and problem drinkers are higher among the young than among older people. Although Japanese-Americans reported consuming less alcohol than Caucasians, their drinking patterns by age were similar: among both United States populations, younger respondents are at higher risk for drinking problems than older respondents, even when alcohol consumption and sociodemographic variables are controlled by logistic regression. However, this association of age and drinking patterns and drinking problems is not universal. Japanese men consumed more alcohol and had a higher proportion of heavier drinkers in the middle age groups; the association between age and drinking problems also varied in this group. In addition to aging, sociocultural factors such as drinking norms probably account for the differences in drinking behavior among different age groups. This study may stimulate further cross-cultural comparison of drinking patterns and problems.

Acculturation↗
PubMed1993

A simplified method for R banding of human oocyte chromosomes.

A simple and reliable R banding technique was developed for karyotyping mature human oocytes. The banding quality obtained is sufficient for the diagnosis of specific aneuploidies and the discrimination between whole chromosomes and separated chromatids. The ability to karyotype human oocytes accurately will facilitate study of the aetiology of chromosomal abnormalities in human concepti.

Chromosome Banding↗
PubMed1993

Average daily alcohol consumption during adult life among decedents with and without cirrhosis: the 1986 National Mortality Followback Survey.

The relationship of alcohol consumption and cirrhosis mortality was examined by sampling 1% of deaths in the U.S. using the 1986 National Mortality Followback Survey. Quantity and frequency of decedent's alcohol consumption was obtained from next of kin through mailed questionnaire. The percentage of decedents with cirrhosis increased sharply with the increasing number of drinks per day. Three drinks per day was associated with a significantly higher percentage of cirrhosis deaths compared with lifetime abstainers for both whites and blacks. Although blacks had a significantly higher percentage of abstainers than whites, of those persons who were reported to drink every day, blacks were more likely to be heavier drinkers (5 or more drinks per day). Blacks did not have a higher risk of cirrhosis mortality than whites for each drinking category. Although Native Americans were oversampled, the number of deaths was too small for statistical comparisons.

Adult↗
PubMed1993

[Cytogenetic study of fragmented embryos not transferred in in vitro fertilization].

A cytogenetic analysis was performed on a sample of 411 human grade IV embryos (i.e. poor morphological quality embryos, never transferred in our in vitro fertilization (IVF) pro Gram) in order to investigate the chromosomal status of these embryos. One hundred eighteen were successfully karyotyped from at least one metaphase. Only 10% displayed normal diploid metaphases. Aneuploidy was the most frequently observed abnormality, with a rate of 36.4%. Six cases of single chromatids were noted and 9 embryos showed structural aberrations. Polyploidy (from 3n to 7n) and haploidy were also observed, suggesting parthenogenetic activation, polyspermy or chromosomal duplication. Mosaicism constituted 6% of the abnormalities. Thirty embryos exhibited fragmented chromosome sets which might result from in vitro delayed fertilization.

Chromosome Aberrations↗
PubMed1992

The association of drinking levels and drinking attitudes among Japanese in Japan and Japanese-Americans in Hawaii and California.

This study examined cross-cultural differences in drinking attitudes and drinking levels and their correlation among Japanese in Japan and Japanese-Americans in Hawaii or California. In most situations, an increase in drinking levels was associated with more tolerant drinking attitudes in all three groups. Abstainers were less likely to say that getting drunk is sometimes all right, whereas the reverse was true for heavier drinkers. Drinking levels among Japanese, especially among Japanese women, were not highly associated with how much drinking was perceived as acceptable in each situation, whereas among Japanese-Americans, drinking levels were highly associated with drinking attitudes. Although the Japanese had generally tolerant attitudes toward drinking, they indicated higher abstention rates before driving than Japanese-Americans regardless of their drinking levels. This may reflect the impact of public education on drunken driving in Japan.

Adolescent↗