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Biomedical subjects

V Johnson

Publications and source records attributed to V Johnson.

At least 91 records · Page 5Linked to original sources
PubMed1990

Serious alcohol and drug problems among adolescents with a family history of alcoholism.

Data concerning adolescents' alcohol- and drug-using behaviors, as well as the drinking patterns of their parents, were obtained from a sample of 1,380 New Jersey youth born between 1961 and 1969. Initially tested between 1979 and 1981 at ages 12, 15 or 18, these subjects were retested two additional times at 3-year intervals (retest rate = 92%). We wished to determine if offspring of families exhibiting a positive history of alcoholism (FH+) reported a serious alcohol or drug problem (including seeking treatment) at a higher rate than those without such backgrounds (FH-). Analyses indicated that FH+ rates for a self-reported alcohol and/or drug problem were about twice the rate for FH- individuals and about 1.5 times as high as the base rate for the entire sample. However, there were no significant differences between the two groups of troubled youth in terms of alcohol or marijuana use patterns or the frequency of use-related negative consequences. Our data also illustrated that FH+ females were as likely as FH+ males to report a serious problem and that FH+ families reported a higher rate of having more than one troubled offspring. It is of special import that these results are based upon observations of a community-based sample of adolescents and young adults in contrast to studies relying upon clinical samples and retrospective reports.

Adaptation, Psychological↗
PubMed1989

Effect of nitroglycerin-induced reduction of left ventricular filling pressure on diastolic filling in acute dilated heart failure.

Recent information has suggested that early diastolic filling may be influenced by the left ventricular filling pressure, especially in the failing left ventricle. Acute severe left ventricular dysfunction was induced in 14 dogs by severe left ventricular global ischemia produced by left main coronary artery microsphere embolization until the left ventricular end-diastolic pressure was greater than or equal to 20 mm Hg. To assess the importance of left ventricular filling pressure on left ventricular diastolic filling, nitroglycerin was infused and titrated to reduce left ventricular end-diastolic pressure to less than 15 mm Hg in seven dogs, whereas the remaining seven dogs were observed for 1 h after acute severe left ventricular dysfunction. In both groups of dogs, severe left ventricular dysfunction resulted in left ventricular dilation and elevation of end-diastolic pressure, reduction in area ejection fraction (echocardiographically determined) and an early redistribution of diastolic filling (increased filling fractions at one-third and one-half diastole) despite prolongation of the time constant of left ventricular pressure decline. Pressure-area plots shifted upward and rightward with severe left ventricular dysfunction and were unchanged at 1 h as were all other variables. Nitroglycerin infusion reduced left ventricular size and filling pressure, redistributed diastolic filling to later in diastole as characterized by reduced filling fraction at one-third diastole (left ventricular dysfunction 48.8 +/- 9.7%, nitroglycerin 17.9 +/- 7.9%, p less than 0.001) and shifted downward left ventricular pressure-area plots. Nitroglycerin also improved the time constant of relaxation (left ventricular dysfunction 83 +/- 15 ms, nitroglycerin 52 +/- 15 ms, p less than 0.001) and lengthened the diastolic filling period.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1989

Familial drinking history as a predictor of alcohol and drug consumption among adolescent children.

Data concerning adolescent alcohol and drug using behaviors, as well as the drinking patterns of their parents, were obtained from a sample of 1,380 New Jersey youth born between 1961 and 1969. Initially tested between 1979 and 1981 at ages 12, 15 or 18, these subjects were retested between 1982 and 1984 (retest rate = 95%). We wish to describe the early differences in patterns of alcohol and drug use between offspring of families exhibiting a positive history of alcoholism (FH+) and those without such backgrounds (FH-). FH+ subjects are compared to three other groups from varying parental backgrounds (heavy drinking nonalcoholic parents, high stress families and symptom-free families) as regarding problem use. Several indicators of problem use (e.g., early onset of intoxication, frequent intoxication, escape drinking) were not found to be more prevalent among FH+ than FH- adolescents. Analyses indicate, however, that FH+ adolescents are more likely than FH- adolescents from symptom-free families to report experiencing problems/consequences related to both drinking and drug taking.

Adaptation, Psychological↗
PubMed1989

An investigation of factors related to intoxicated driving behaviors among youth.

This study assessed the prevalence of driving under the influence of alcohol and marijuana among a sample of 18 and 21 year olds and examined the across-time relationships between intoxicated driving and consumption, risk-taking/impulsive orientation, negative intrapersonal state, stress and use of alcohol and other drugs to cope with problems. Self-report data were collected from 556 men and women, ages 18 and 21, at two points in time. The data indicated that at least a minimum level of drinking and driving, as well as smoking marijuana and driving, is engaged in at least once for the majority of youth. Correlations between eight driving behaviors and consumption variables indicated that frequency of substance use was strongly related to frequency of driving while intoxicated (DWI). Regression analyses revealed that coping use of substances was the strongest predictor of driving under the influence. A path model examining the effect of stress, negative states and risk-taking orientations (T1) on driving under the influence as mediated through coping use (T2) was tested. Results showed that risk-taking orientation was the strongest predictor of DWI, both directly and indirectly (as mediated through coping use). Findings suggest that impaired driving may be part of a global syndrome of risk-taking behavior and is an activity engaged in most often by those who frequently use alcohol and other drugs to cope with problems.

Accidents, Traffic↗
PubMed1988

Adolescent alcohol and marijuana use: a longitudinal assessment of a social learning perspective.

A social learning model which incorporates measures from both the sociological perspective of differential association and the psychological perspective of behavior reinforcement is analyzed as an explanation of continued alcohol and marijuana use among youths. Data were gathered at two points in time from a sample of adolescents from New Jersey. The measurement and structural relationships among peer associations, attitudes, reinforcing and punishing consequences, and patterns of use were examined. It was found that, overall, the model fit the data for use of both substances, proving to be invariant across age and gender groups. The most pronounced difference between the alcohol and marijuana models was that differential associations exhibited the strongest relationship to maintenance of alcohol use while reinforcers were most salient to continued marijuana use.

Adolescent↗
PubMed1986

Renal reabsorption of phosphate during development: whole-kidney events.

The isolated perfused kidney of the guinea pig has been used to assess the mechanism that accounts for the maintenance of the positive phosphate (Pi) balance during development. The kidneys obtained from mature guinea pigs (n = 25) had a glomerular filtration rate (GFR) of 0.48 +/- 0.04 ml/min (mean +/- SE), whereas those of the newborn (n = 20) had a GFR of 0.15 +/- 0.02 ml/min. These values compare favorably with those observed in intact animals. The fractional excretion of Na+ (FENa) was 3.8 +/- 0.7% in the mature kidneys and 4.7 +/- 0.7% in the newborn kidneys. The maximal tubular reabsorption of Pi (TmPi) by the newborn kidney was 24.3 +/- 2.8 micrograms/min. The filtered load at which the TmPi of the newborn was reached exceeds by 2.5-fold the filtered load of Pi encountered under physiological conditions. In the adult the TmPi was 53.9 +/- 2.6 micrograms/min. The filtered load at which the TmPi of the adult was reached is only slightly higher than the average normal filtered load of Pi. The TmPi/GFR was significantly higher (P less than 0.02) in the newborn (117.4 +/- 10.8 micrograms X min-1 X ml-1 GFR) compared with the adult (82.6 +/- 3.6 micrograms X min-1 X ml-1 GFR). Moreover, at any filtered load of Pi below Tm the newborn animals reabsorbed twofold more Pi per gram kidney weight than the adult (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1986

An application of three deviance theories to adolescent substance use.

This study tests the applicability of aspects of three theories of deviance--differential association, control, and strain--to the use of alcohol and drugs among a representative cross-section of 12-, 15-, and 18-year-olds. Regression analyses are conducted separately on each theory as well as on an overall model combining aspects of all three perspectives. Results show that differential association theory is a far more powerful predictor of adolescent alcohol and drug use than either the control or strain theories. The predictive power of the overall model is dependent upon the type of substance used as well as the age of the subject; however, the model is invariant between males and females.

Adolescent↗
PubMed1984

Hypokalemic periodic paralysis.

Hypokalemic periodic paralysis is an unusual disease that may begin dramatically. Although terrifying to the patient, the attacks can usually be controlled if the proper diagnosis is made. Although much has been done to determine the pathogenesis, many questions remain unanswered.

Adult↗
PubMed1977

Renal extraction, filtration, absorption, and catabolism of growth hormone.

Renal handling of homologous labeled rat growth hormone (125I-rGH) was studied in the intact rat and in a filtering and nonfiltering isolated perfused rat kidney preparation. Plasma disappearance rate, renal accumulation, renal clearance (C), glomerular sieving coefficient (GSC), absorption rates, and fate of absorbed hormones were determined. 125I-rGH is extensively filtered (GSC approximately 0.6) and subsequently absorbed by the tubular epithelium (C/GRF less than 1%). The absorption process of 125I-rGH has a high capacity and is inhibited by iodoacetate. Absorbed 125I-rGH is catabolized and a detectable product of catabolism (125I-monoiodotyrosine) is returned to the circulation. A nonfiltering kidney preparation with adequate renal perfusate flow was developed to study the contribution of the peritubular side to the renal handling of small proteins. Experiments in the nonfiltering kidney show that renal accumulation, extraction, and catabolism of 125I-rGH from the peritubular side is minimal when compared to that occurring from the luminal side. The ratio of the renal extraction rate of 125I-rGH in the isolated kidney and the mean plasma disappearance rate of 125I-rGH in the intact rat was 0.67, demonstrating that the kidneys account for the major fraction of the total plasma turnover of GH in the rat.

Animals↗