Poly-Drug and Marijuana Use Among Adults Who Primarily Used Methamphetamine

Abstract

This study examines health and legal problems associated with use of commonly reported substances and combinations of substances in a sample of adults with long histories of methamphetamine (meth) use. Data are from a 2009–11 eight-year follow-up interview in an intensive natural history study (N = 373). Respondents who had not used illicit substances in the year preceding the follow-up interview (38%) were compared to users of marijuana-only (16%), meth-only (7%), and poly-drug users who used meth + marijuana but not heroin or cocaine (19%), and poly-drug users who used heroin and/or cocaine (20%). Multinomial regression results indicate that compared to drug-abstinent individuals, greater depressive symptomatology was reported for poly-drug users of meth + marijuana (p = .001), and arrest rates were higher for poly-drug users who used heroin/cocaine (p = .006); no differences in health, mental health, or criminal involvement were observed for meth-only users compared to abstinent individuals. Users of marijuana-only and poly-drug users of heroin/cocaine experienced poorer physical health status than those who were abstinent. To further explore this finding, use of marijuana for medical reasons was examined by drug use group. Overall, health and criminal outcomes varied based on type and combination of substances used, and these differences should be considered when planning treatment strategies.     

Role of mineralocorticoid receptors in arterial stiffness in human aging

Arterial stiffness, an independent predictor of cardiovascular disease, is increased in aging, but the underlying mechanisms are not completely understood. Mineralocorticoid receptors (MR) may contribute to oxidative stress and arterial stiffness in healthy older adults. To test the hypothesis that short-term MR blockade may reduce oxidative stress and improve arterial stiffness, we conducted a randomized, double blind, crossover study using the selective MR blocker Eplerenone or placebo in 23 older adults (age, 64 ± 1 years; mean ± SE) free from overt cardiovascular and other clinical disease (e.g, diabetes, renal and liver disease). In response to MR blockade, brachial and carotid blood pressure decreased (P ≤ 0.01). However, MR blockade had no effect on oxidative stress (oxidized LDL, 61.2 ± 6.8 vs. 62.4 ± 7.4 U/L, P = 0.9; placebo vs. Eplerenone) and arterial stiffness (aortic pulse wave velocity (PWV), 9.17 ± 1.19 vs. 8.92 ± 1.19 m/s, P = 0.5; leg PWV, 13.45 ± 0.45 vs. 12.81 ± 0.47 m/s, P = 0.3; arm PWV, 11.43 ± 0.62 vs. 11.73 ± 0.68 m/s, P = 0.7; carotid artery compliance, 0.150 ± 0.013 vs. 0.149 ± 0.014 mm²/mm Hg, P = 0.8; distensibility, 23.1 ± 1.8 vs. 23.3 ± 1.7 10^− 3/kPa, P = 0.8; β stiffness index, 3.5 ± 0.3 vs. 3.6 ± 0.3, P = 0.6; and augmentation index, 16.0 ± 2.2 vs. 15.6 ± 2.8%, P = 0.8). These results provide the first evidence that MR do not appear to contribute to oxidative stress in human aging and that short-term MR blockade does not result in reduced oxidative stress and improved arterial stiffness.     

Association of liver cirrhosis related IgA nephropathy with portal hypertension

A high incidence of IgA nephropathy has been reported in patients with liver cirrhosis, though, clinically evident nephrotic syndrome is very uncommon. Impaired hepatic clearance of circulating IgA immune complexes and subsequent deposition in renal glomeruli has been considered principally in the pathogenesis of liver cirrhosis associated IgA nephropathy. Here we report on a patient with cryptogenic liver cirrhosis and splenic vein thrombosis, who presented with nephrotic syndrome. Renal biopsy showed findings consistent with IgA nephropathy. Lower endoscopy showed features of portal hypertensive colopathy. Following initiation of propranolol and anticoagulant treatment to reduce portal pressure, a gradual decrease of proteinuria and hematuria to normal range was noted. The potential pathogenetic role of portal hypertension in the development of IgA nephropathy in cirrhotic patients is discussed.     

From the Cover: Transgenic multivitamin corn through biofortification of endosperm with three vitamins representing three distinct metabolic pathways

Vitamin deficiency affects up to 50% of the world''s population, disproportionately impacting on developing countries where populations endure monotonous, cereal-rich diets. Transgenic plants offer an effective way to increase the vitamin content of staple crops, but thus far it has only been possible to enhance individual vitamins. We created elite inbred South African transgenic corn plants in which the levels of 3 vitamins were increased specifically in the endosperm through the simultaneous modification of 3 separate metabolic pathways. The transgenic kernels contained 169-fold the normal amount of β-carotene, 6-fold the normal amount of ascorbate, and double the normal amount of folate. Levels of engineered vitamins remained stable at least through to the T3 homozygous generation. This achievement, which vastly exceeds any realized thus far by conventional breeding alone, opens the way for the development of nutritionally complete cereals to benefit the world''s poorest people.     

Novel software for quantitative evaluation and graphical representation of masticatory efficiency

Blending of chewing gums of different colours is used in the clinical setting, as a simple and reliable means for the assessment of chewing efficiency. However, the available software is difficult to use in an everyday clinical setting, and there is no possibility of automated classification of the patient's chewing ability in a graph, to facilitate visualisation of the results and to evaluate potential chewing difficulties. The aims of this study were to test the validity of ViewGum – a novel image analysis software for the evaluation of boli derived from a two‐colour mixing ability test – and to establish a baseline graph for the representation of the masticatory efficiency in a healthy population. Image analysis demonstrated significant hue variation decrease as the number of chewing cycles increased, indicating a higher degree of colour mixture. Standard deviation of hue (SDHue) was significantly different between all chewing cycles. Regression of the log‐transformed values of the medians of SDHue on the number of chewing cycles showed a high statistically significant correlation (r² = 0·94, P < 0·01). ViewGum eliminates drawbacks of previous two‐colour chewing gum test methods by the simplicity of its application. The newly developed ViewGum software provides speed, ease of use and immediate extraction of clinically useful conclusions to the already established method of chewing efficiency evaluation and is a valid adjunct for the evaluation of masticatory efficiency with two‐colour chewing gum.     

Age-associated impairement in endpoint accuracy of goal-directed contractions performed with two fingers is due to altered activation of the synergistic muscles

The purpose of this study was to determine whether older adults compared with young adults exhibit impaired end-point accuracy during a two-finger task due to altered activation of the contributing synergistic muscles. Nine young (21.3 years ± 1.6 years, 4 men) and 9 older (73.1 years ± 6.4 years, 5 men) were instructed to accurately match the center of a target with concurrent abduction of the index and little fingers (synergistic two-finger task). The target comprised of 20% MVC and 200 ms. Visual feedback of the force trajectory and target was provided 1s after each trial. Subjects completed 40 trials and the last 10 were used for analysis. Endpoint accuracy was quantified as the normalized deviation from the target in terms of peak force (peak force error), time-to-peak force (time-to-peak force error), and a combination of the two (overall error). Motor output variability was quantified as the standard deviation and coefficient of variation (CV) of peak force and time to peak force. The neural activation of the involved synergist muscles (first dorsal interosseus (FDI) and abductor digiti minimi (ADM)) was quantified with the electromyography (EMG) amplitude (root mean square) and its frequency structure (wavelet analysis). Older adults exhibited significantly greater peak force (46.7 ± 10% vs. 24.9 ± 3.2%) and overall endpoint error (68.5 ± 9.7% vs. 41.7 ± 4.3%), whereas the time to peak force error was similar for the two age groups. Older adults also exerted greater peak force variability than young adults, as quantified by the CV of peak force (34.3 ± 3.5% vs. 24.1 ± 2.3%). The greater peak force error in older adults was associated with changes in the activation of the ADM muscle but not the FDI. Specifically, greater peak force error was associated with greater power from 13-30 Hz and lesser power from 30-60 Hz. These results, therefore, suggest that older adults compared with young adults exhibit impaired endpoint force accuracy during a two finger task because of altered activation of one of the synergist muscles.