The cost of harmful alcohol use in South Africa: A reply to Murray and Barr (2022)

Letter by Matzopoulos et al. on article by Murray and Barr (Murray M, Barr GDI. The cost of harmful alcohol use in South Africa: A commentary. S Afr Med J 2022;112(3):187-188. https://doi.org/10.7196/SAMJ.2022.v112i3.16354).

The efficacy of a blended motivational interviewing and problem solving therapy intervention to reduce substance use among patients presenting for emergency services in South Africa: A randomized controlled trial

Background

The treatment of substance use disorders is a public health priority, particularly in South Africa where the prevalence of these disorders is high. We tested two peer-counsellor delivered brief interventions (BIs) for risky substance use among adults presenting to emergency departments (EDs) in South Africa.

Methods

In this randomised controlled trial, we enrolled patients presenting to one of three 24-hour EDs who screened at risk for substance use according to the Alcohol, Smoking, and Substance Involvement Screening Test (ASSIST). Eligible patients were randomly allocated to one of three conditions: Motivational Interviewing (MI), blended MI and Problem Solving Therapy (MI-PST) or a Psycho-educational Control Group (CG). The primary outcome was reduction in ASSIST scores at three months follow-up.

Results

Of the 2736 patients screened, 335 met inclusion criteria, were willing to participate in the intervention and were randomised to one of three conditions: 113 to MI, 112 to MI-PST and 110 to CG. ASSIST scores at three months were lower in the MI-PST group than they were in the MI and CG groups (adjusted mean difference of −1.72, 95 % CI −3.36 - -0.08). We recorded no significant difference in ASSIST scores between the CG and MI group (adjusted mean difference of −0.02, 95 % CI −2.01 - 1.96).

Conclusion

With the addition of minimal resources, BIs are feasible to conduct in EDs in a low resourced country. These preliminary findings report that MI-PST appears to be an effective BI for reducing substance use among at risk participants. Further research is required to replicate these findings with effort to limit attrition, to determine whether reductions in substance use are persistent at 6 and 12 month follow-up and whether parallel changes occur in other indications of treatment outcomes, such as injury rates and ED presentations.

Trial registration

This trial registered with the Pan African Clinical Trial Registry (PACTR201308000591418)

The efficiency of oxidative phosphorylation and the rapid control by thyroid hormone of nicotinamide nucleotide reduction and transhydrogenation in intact rat liver mitochondria

In confirmation of previous work enhancement of the fluorescence emission of reduced nicotinamide nucleotides in intact rat liver mitochondria was found to depend on incubation conditions. Under standard conditions the enhancement is constant at 4.8-fold in states 3 and 4 and is not altered by thyroidectomy of the animal 6 weeks prior to experiment. The ADP-induced (state 4----state 3----state 4) fluorescence changes are significantly different in intact mitochondria from normal and hypothyroid animals and reflect the decreased rate and efficiency of oxidative phosphorylation after thyroidectomy. Incubation of liver homogenates in vitro for 15 min with 1 microM triiodothyronine before isolating mitochondria significantly restores their ADP response towards normal. Direct addition of hormone to isolated mitochondria was ineffective. Enzymatic measurement of mitochondrial extracts shows that thyroidectomy leads to increases in the contents of NAD(H) by 22% and NADP(H) by 33%. With glutamate as substrate ADP-induced changes in the reduced/oxidized ratio of NAD+ are not significantly altered in hypothyroid preparations. By contrast the NADP+ ratio remains substantially more reduced in state 3 than it does in normal mitochondria. The hypothesis is advanced that the decreased efficiency of hypothyroid preparations in phosphorylating ADP may be the result of increased energy-linked transhydrogenase activity. This is needed to supply NADPH via the glutathione peroxidase for reducing endogenously formed peroxides. Direct reduction of mitochondrial glutathione with dithiothreitol had no substantial effect on ADP/O ratios or on ADP-induced redox cycles in either normal or thyroidectomised preparations. This decisively eliminates the possibility that lowered phosphorylation efficiency is the result of a leak of reducing equivalents via glutathione peroxidase.

Short-term control of mitochondrial adenine nucleotide translocator by thyroid hormone

An improved simple technique for measuring adenine nucleotide translocator activity at low medium substrate concentrations is described. Confirming previous reports, thyroidectomy was shown to lead to lowered translocator activity in rat liver mitochondria. The rapidly exchangeable portion of the matrix nucleotide also decreased in hypothyroid preparations even though the total nucleotides increased substantially. The apparent Km of translocator for ADP increased from 2.8 to 6.2 microM in hypothyroid preparations: Mg2+ ions raised this to about 20 microM. All of these changes in adenine nucleotide translocation were entirely reversed by 15 min after a single intravenous near-physiological dose of triiodothyronine.