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Biomedical subjects

R Jardine

Publications and source records attributed to R Jardine.

13 recordsLinked to original sources
PubMed1991

The inheritance of alcohol consumption patterns in a general population twin sample: II. Determinants of consumption frequency and quantity consumed.

Genetic models were fitted to self-report data on frequency of alcohol consumption and average quantity consumed when drinking, from 3,810 adult Australian twin pairs. Frequency of consumption is determined both by an abstinence dimension, which is strongly influenced by shared environmental effects but not by genetic effects, and by an independent frequency dimension, which is influenced by genetic effects in both sexes and possibly by shared environmental affects in men. Quantity of alcohol consumed is likewise determined by an environmental abstinence dimension and by an independent and partly heritable quantity dimension. The best-fitting model allowed for two routes to abstinence: those who were not abstainers by virtue of their position on the abstinence dimension could nonetheless become abstainers by their position on the second, frequency (or quantity) dimension. Heritability estimates were 66% in women and 42-75% in men, for frequency; and 57% in women and 24-61% in men, for quantity.

Adult↗
PubMed1990

Efficacy of oral sotalol in reentrant ventricular tachycardia.

Oral sotalol was given to 64 patients (78% postinfarction) with recurrent, reentrant ventricular tachycardia (VT) during an average follow-up period of 19.7 months. Fifty-nine (92%) patients had previously experienced recurrent ventricular tachycardia, in spite of having received an average of three conventional antiarrhythmic drugs (13 had previously failed on other Class III drugs). The nature and mechanism of the VT was proved with electrophysiologic testing (EPS), and the chronic sotalol dosage was determined by repeated EPS at 3- to 4-day intervals until the VT was no longer inducible. Sotalol failed in five patients and was discontinued in six patients because of severe side effects (three proarrhythmic effects, including two with torsades de pointes)--a total of 18%. Sotalol was successful alone in 42 patients (65%) and in combination with another antiarrhythmic drug in 11 patients (18%). The average dose of sotalol required for success was 589 mg; 658 mg was the mean daily dose when given alone and 486 mg when given in combination. Side effects were common and were due mainly to the beta-blocking effects of sotalol. Dual chamber pacing was required by 11 patients because of poorly tolerated bradycardia, and 14 patients remained symptomatic from worsening of the cardiac failure in spite of pacing, increased diuretics, or vasodilator therapy. The average drug dosage was the same for symptomatic (680 mg) and asymptomatic (627 mg) patients. Sotalol is a valuable antiarrhythmic drug for reentrant ventricular tachycardia. High doses are needed, and at these doses the beta-blocking activity is responsible for most of the side effects.

Administration, Oral↗
PubMed1989

Interactive effects of genotype and social environment on alcohol consumption in female twins.

Information about drinking practices has been obtained by questionnaire from 1,984 monozygotic and dizygotic adult female twin pairs from the Australian twin register, including 1,690 pairs where both twins have used alcohol. Statistical analyses of these data show that marital status is an important modifier of genetic effects on drinking habits. In young twins, aged 30 years or less, genetic differences between individuals account for only 31% of the variance in alcohol consumption of married respondents, but for 60% of the variance of unmarried respondents. In twin pairs, aged 31 years or more, genetic differences account for 46-59% of the variance in married twins, but for 76% of the variance in unmarried twins. In our young sample (average age 35 years) there is no evidence that individuals genetically predisposed to heavy drinking are any less likely to be married than the rest of the population. Some alternative explanations of these findings are also rejected.

Adult↗
PubMed1988

Anxiety disorders and neuroticism: are there genetic factors specific to panic?

Data from 2,903 adult same-sex twin pairs were analysed to investigate whether the genetic determinants of symptoms of panic are different from those underlying the neuroticism personality trait. Our results suggest that much of the genetic variation influencing the physical symptoms associated with panic is of the nonadditive type, perhaps due to dominance or epistasis. In both sexes these nonadditive genetic effects on physical symptoms influence the reporting of "feelings of panic". In males they also account for as much as half the genetic variance in neuroticism. The remainder is additive and also accounts for the balance of genetic variation in "feelings of panic". In females genetic variance in neuroticism is entirely additive but is not an important source of covariation with either panic symptom. Thus, symptoms of panic seem to be shaped in part by unique genetic influences which do not affect other anxiety symptoms. That a substantial part of the genetic variance in neuroticism in males may be due to the nonadditive effects on physical symptoms of panic may help to explain the rather low correlation between the genetic influences found to affect neuroticism in males and their counterparts in females.

Adult↗
PubMed1986

Late potentials, ventricular stimulation and ventricular tachycardia.

Late potentials are depolarizations which arise from areas of delayed ventricular activation and may indicate a propensity for ventricular tachycardia. Sixty-four subjects were assessed by non-invasive measurement. Late potentials were not present in 20 subjects with normal hearts nor in 6 patients with cardiac disease but with no evidence of ventricular tachycardia (VT). Seventeen of 20 patients with recurrent sustained ventricular tachycardia (RSVT) and 2 of 10 patients with unsustained VT had late potentials. None of the 6 patients with automatic VT or the 2 patients with torsades de pointe had late potentials. In a subgroup of 28 symptomatic patients in whom programmed ventricular stimulation was performed, late potentials correlated with inducibility of sustained VT (P less than 0.05). Late potentials may therefore serve as a useful marker of RSVT and confirm a re-entrant mechanism of VT.

Action Potentials↗
PubMed1986

Transmission of social attitudes.

Data gathered in Australia and England on the social attitudes of spouses and twins are largely consistent with a genetic model for family resemblance in social attitudes. There is substantial assortative mating and little evidence of vertical cultural inheritance.

Attitude↗
PubMed1984

Genetic covariation between neuroticism and the symptoms of anxiety and depression.

A genetic analysis of the trait of neuroticism and symptoms of anxiety and depression in 3,810 pairs of adult MZ and DZ twins is reported. Differences between people in these measures can be explained simply by differences in their genes and in their individual environmental experiences. There is no evidence that environmental experiences that are shared by cotwins, such as common family environment or social influences, are important. There are differences between the sexes in gene action affecting neuroticism, and genetic effects become more pronounced with age in females. The lack of evidence for dominance variance affecting neuroticism contrasts well with the detection of considerable genetical nonadditivity for extraversion in the same sample and reinforces the view that these two traits are not only statistically, but also genetically, quite independent. An analysis of the causes of covariation between anxiety, depression, and neuroticism shows that additive gene effects are more important causes of covariation than environmental factors. Genetic variation in symptoms of anxiety and depression is largely dependent on the same factors as effect the neuroticism trait. However, there is also evidence for genetic variation specific to depression.

Adolescent↗
PubMed1984

Causes of variation in drinking habits in a large twin sample.

A genetic analysis of alcohol consumption in 3810 pairs of adult twins is reported. When no correction was made for age, individual environmental variance, including non-repeatable errors of reporting, accounted for approximately 44% of variation in both sexes. In females, there was no evidence of shared environmental effects and 56% of the variance was genetic in origin. In males, only 36% of the variance was genetic and common environmental effects accounted for the remaining 20% of individual differences. For females, the results for younger (30 years and under) and older (over 30) twins were similar. For males, however, the effect of age was striking. In younger male twins over 60% of the variance was genetic in origin, with the remaining variance due to environmental influences unique to the individual. In older twins genetic differences do not appear to be important, with approximately 50% of the total variance due to individual environmental differences and the remaining 50% due to the effect of the common family environment. Our results suggest that both age and sex need to be considered when analysing the causes of variation in alcohol consumption.

Adolescent↗
PubMed1983

Further experience with long-term captopril therapy in severe refractory congestive heart failure.

Fifty patients in severe congestive heart failure (CHF) were treated with captopril (Capoten; Squibb), an oral angiotensin-converting enzyme inhibitor, over a 2-year period (range 3-24 months, mean 8,6 +/- 7,7 months). At entry, all patients were in New York Heart Association (NYHA) functional class IV despite high-dose diuretic and conventional vasodilator therapy. The overall cumulative survival at 6 and 12 months was 64% and 53% respectively. There were 22 deaths (18 during captopril therapy) including 8 sudden deaths. At 2-year follow-up (mean 14,6 +/- 6,9 months), there were 25 survivors on captopril; 18 in NYHA class I or IIS and 7 in class IIM or III. Diuretic requirements were decreased considerably in all. Side-effects were common but transient and in no case did captopril have to be withdrawn. We confirm our earlier conclusion that captopril has long-term beneficial effects and is a highly effective drug in the treatment of patients with CHF refractory to currently accepted therapy. Sudden death despite satisfactory clinical improvement continues to cause concern. Precautions which may reduce or avoid these are briefly discussed.

Adolescent↗