The folic acid endophenotype and depression in an elderly population

OBJECTIVES

Folate status and/or genes have been linked to depression in a number of studies. This may be via a direct action (or actions) on neuronal membranes or indirect effects through the metabolism of methyl groups involved in neurotransmitter synthesis. This study examines folate and related thiol metabolism that might underpin either phenomenon.

DESIGN

Cohort study describing the relationship between several genetic and nutritional aspects of folic acid homeostasis and depression assessed by the HADS psychometric index in an elderly cohort.

SETTING

New South Wales (Australia) retirement village.

PARTICIPANTS

118 elderly participants (age 65-90 years).

RESULTS

Stepwise multiple regression was used to determine the best statistical model to predict depression; C677T-MTHFR (p=0.0103) was found to be positively associated with depression, while the thiol dipeptide Cys-Gly was negatively associated (p=0.0403). The statistical models used accounted for the major folate related indices (genetic and biochemical) that are most often evaluated in the context of health and disease. When only genetic data were examined for interactions, C677T-MTHFR was found to be negatively associated with the HADS Depression Index Score (p=0.0191).

CONCLUSION

The potential influence of Cys-Gly on this phenotype is novel, and of considerable interest given that it has been linked to altered spontaneous activity and sedation in an animal model. Cys-Gly is a recognised ligand at the N-methyl-D-aspartatic acid (NMDA) subclass of glutamate receptor, a system associated with depression. In addition, the C677T-MTHFR association adds further support to existing findings underscoring the potential role of folate in depression.

Mechanisms of increase in plasma triacylglycerol concentrations as a result of high carbohydrate intakes in patients with non-insulin-dependent diabetes mellitus

To determine the mechanisms of increase in plasma triacylglycerol concentrations after high dietary intakes of carbohydrates, 10 men with non-insulin-dependent diabetes mellitus (NIDDM) were fed an isoenergetic high-carbohydrate diet (55% of energy as carbohydrate and 30% as fat) and a high-monounsaturated-fat diet (45% of energy as fat and 40% as carbohydrates) for 6 wk in a randomized, crossover manner. The high-carbohydrate diet raised fasting plasma triacylglycerol concentrations by 26% (P = 0.007) but did not affect postheparin lipoprotein lipase (P = 0.2) or hepatic lipase activities (P = 0.9). The oral-fat-tolerance test labeled with retinyl palmitate also revealed no differences in postprandial plasma triacylglycerol (P = 0.37) or retinyl palmitate clearances (P = 0.34) between the two diets. We conclude that the increase in plasma triacylglycerol concentrations with high-carbohydrate diets in men with NIDDM is not due to reduced lipolysis or diminished postprandial clearance of triacylglycerol-rich lipoproteins but is primarily due to increased hepatic secretion of very-low-density-lipoprotein triacylglycerols.

'Exaggerated adrenarche' in children presenting with premature adrenarche

OBJECTIVE

Previous reports of endocrinological profiles in children presenting with premature adrenarche have not shown consistent abnormalities. We therefore aimed to review the clinical and biochemical aspects of a large number of patients presenting with premature adrenarche without virilization and determine the relation between clinical and biochemical characteristics and the frequency of adrenal steroid disorders.

DESIGN AND PATIENTS

Eighty-eight patients presenting with adrenarche without virilization during 1985-1992 were retrospectively reviewed. There were 72 girls and 16 boys. All were normotensive and had either prepubertal breasts or testes < 4 ml. In patients with high adrenal androgen levels, adrenal tumours had been excluded by either adrenal ultrasound or CT scan.

MEASUREMENT

We recorded clinical manifestations, auxological data, bone age, biochemical results including basal 17OH-progesterone (b17OHP), dehydroepiandrosterone sulphate (DHEAS), androstenedione (delta 4A), testosterone, cortisol and stimulated 17OHP and cortisol. ACTH stimulation tests (using soluble Synacthen 250 micrograms intramuscularly and collecting blood at 0, 30 and 60 minutes) were performed when clinically indicated. 17OH-Pregnenolone (17OHPreg) was also measured during ACTH stimulation tests in 13 individuals to look for abnormalities of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD).

RESULTS

The age of onset ranged from 3 to 9.5 years (mean 6.8 +/- 1.3). There were no significant differences by sex for height SDS, weight SDS or % ideal body weight, but bone age advancement was greater in males (P < 0.02). The most common presenting clinical manifestation was premature appearance of pubic hair in 93.8%, the other 6.2% presenting with body odour, acne and/or hirsutism. Twelve patients had b17OHP > 6 nmol/l of whom 5 were diagnosed as having congenital adrenal hyperplasia (CAH) resulting from 21-hydroxylase deficiency after ACTH stimulation tests. A further 33 patients who had b17OHP < 6 nmol/l had normal 17OHP and cortisol responses to ACTH stimulation. Patients, after excluding those with CAH, were divided on the basis of their DHEAS levels into prepubertal (< 1.5 mumol/l), pubertal (1.5-6 mumol/l) and above pubertal range (> 6 mumol/l). The 8 patients with DHEAS values above the pubertal range were described as having 'exaggerated adrenarche'. There were no significant clinical differences between these 3 groups, but significant differences were found for bone age advancement and the steroids, b17OHP, delta 4A and testosterone. There was a strong correlation between DHEAS and delta 4A (r = 0.623, P < 0.001). The 'exaggerated adrenarche' group had higher 17 OHPreg/17OHP ratios at 60 minutes after stimulation but these were not diagnostic for 3 beta-HSD deficiency.

CONCLUSION

The value of assessing basal steroids in children presenting with premature adrenarche is demonstrated in this series with 5.7% being diagnosed with 21-hydroxylase deficiency and 9.1% with 'exaggerated adrenarche'. No relation was found between adrenal steroids and clinical features except for the acceleration of bone age. The relation between 'exaggerated adrenarche' and future ovarian hyperandrogenism needs further evaluation.

Activities of lipoprotein lipase and hepatic triglyceride lipase in postheparin plasma of patients with low concentrations of HDL cholesterol

Previous investigations have shown that abnormalities in the postheparin plasma levels of the lipolytic enzymes, lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL), are correlated with variations in plasma high-density lipoprotein cholesterol (HDL-C) levels. The present study was performed to determine correlations between the postheparin plasma activities of these two enzymes and HDL levels in a sizable number of subjects with low HDL-C levels. Two types of low-HDL subjects were investigated: 159 male subjects with low HDL-C (< 40 mg/dL) and normal triglyceride (< 250 mg/dL) levels (the low-HDL group) and 80 male subjects with low HDL-C (< 40 mg/dL) and elevated triglyceride (> or = 250 mg/dL) levels (the low-HDL/high-TG group). Postheparin plasma activities of LPL and HTGL were determined in these two groups, and these levels were compared with those obtained from 51 normolipidemic (normal-HDL) male subjects. Postheparin LPL activities were significantly lower in the low-HDL and low-HDL/high-TG groups (mean +/- SD, 9.9 +/- 2.9 and 10.4 +/- 3.0 mmol/h per liter, respectively; P < .001 for both) compared with the normal-HDL group (12.5 +/- 3.7 mmol/h per liter). Conversely, postheparin HTGL activities were significantly higher in the low-HDL and low-HDL/high-TG groups (39.3 +/- 16.2 and 44.4 +/- 16.7 mmol/h per liter, respectively; P < .001 for both) compared with the normal-HDL group (29.7 +/- 11.3 mmol/h per liter). Consequently, mean LPL/HTGL ratios were markedly lower in the two low-HDL groups compared with the normal-HDL group.(ABSTRACT TRUNCATED AT 250 WORDS)

Dose-related effects of phenobarbital on hepatic glutathione-S-transferase activity and ligandin levels in the rat

To determine which individual parameters contribute to the increased bilirubin clearance which follows phenobarbital administration in the rat, dose response studies are being conducted relating changes in various aspects of bilirubin transport to the dose of phenobarbital administered. The relationships between phenobarbital dose, immunoreactive ligandin concentrations, and cytosolic glutathione-S-transferase (GSHT) enzymatic activities were determined in the 100,000g liver cytosol obtained from non-fasted male Sprague-Dawley rats, treated for 6 days (ip) with either phenobarbital at various doses ranging from 1 to 125 mg/kg/day or distilled water. Ligandin levels were measured by radioimmunoassay employing an antiserum which reacts with both GSHT-1 (Ya) and -2 (Yc) subunits. Ligandin concentration increased in a dose-dependent fashion, achieving a maximal observed value of 278% of control at the highest administered phenobarbital dose. Values were significantly elevated compared to controls at doses as low as 3 mg/kg/day. GSH-dependent delta 5-3-ketosteroid isomerase (KSI) activity, which reflects predominantly GSH transferase subunit 1, and GSHT activity against 1-chloro-2,4-dinitrobenzene (CDNB) also increased over the entire range of phenobarbital doses administered. Both of these enzymatic activities were highly correlated with immunoreactive ligandin levels (KSI: r = 0.89, p less than 0.005; GSHT (CDNB): r = 0.92, p less than 0.001). By contrast, GSHT activity against 1,2-dichloro-4-nitrobenzene (DCNB), which resides principally on GSHT subunits not present in ligandin, did not correlate significantly with measured ligandin concentrations. These studies indicate that phenobarbital is capable of inducing immunoreactive ligandin concentrations and related enzymatic activities at doses as small as 5% of those commonly employed to demonstrate this effect.

Effects of endotoxin on iron uptake by the hepatocyte

Administration of endotoxins is often followed within 12-24 h by marked hypoferremia. Because the hepatocyte is the major site of both iron storage and transferrin synthesis, we have investigated the effects of an Escherichia coli endotoxin (lipopolysaccharide, LPS) on these parameters on isolated hepatocytes from normal Wistar rats (ND), rats previously treated intraperitoneally with 2.5 mg/kg (LD) or 25 mg/kg (HD) LPS, and control rats injected intraperitoneally with sterile saline (CD). No effects were observed on iron uptake from transferrin by ND cells incubated in vitro with up to 350 micrograms LPS/10(7) hepatocytes. There was also no significant difference in iron uptake between CD, HD, and LD hepatocytes 1 h after LPS injection. However, hepatocytes isolated 24 h after LPS administration took up iron significantly faster than controls. The uptake of non-transferrin-bound iron was also increased in HD and LD hepatocytes at 24 h but only in HD cells at 1 h. Transferrin binding was not altered in LPS-treated cells from ND rats but was depressed in cells from LPS-treated rats both at 1 h and at 24 h after injection. Transferrin receptor recycling was significantly increased at 24 h in cells from both LD and HD rats. Transferrin and total protein synthesis were also depressed at 1 h in LPS-treated rats, returning to normal values at 24 h. Direct preincubation of ND cells, however, failed to increase synthesis except at the highest concentrations of LPS. We conclude that LPS has an immediate (although indirect) effect on protein synthesis by the hepatocyte but not on iron uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Depression of iron uptake from transferrin by isolated hepatocytes in the presence of ethanol is a pH-dependent consequence of ethanol metabolism

Incubation of freshly isolated rat hepatocytes with highly purified radiolabeled rat transferrin in weakly buffered medium in the presence of 10 mM ethanol resulted in a marked diminution of iron uptake by these cells, associated with a greater pH depression than in ethanol-free control studies. This effect on iron uptake persisted, even when the cells were preincubated for 90 min with ethanol before the addition of transferrin. Increasing the buffering capacity of the system or the addition of a metabolic inhibitor of alcohol dehydrogenase (4-methylpyrazole) returned iron uptake to control values. Acetaldehyde, acetate, lactate (products of ethanol metabolism), and 3-butanol (an alcohol not metabolized by alcohol dehydrogenase) had no influence on iron uptake. Further investigation of iron uptake over the pH range 6-8.5 revealed a marked dependency of iron uptake on the extracellular pH. Leucine incorporation into cell protein was also found to be pH dependent. It is suggested that, in the light of current understanding of transferrin recycling by other cell types, the disturbances of iron homeostasis observed in alcoholics can be partially accounted for by alterations in their acid-base metabolism.

A burn specific health scale

The outcome of burn care is conventionally measured in terms of mortality. To extend our understanding beyond this level, and specifically to develop insight into the morbidity and other sequelae or burn injury, we have constructed a Burn-Specific Health Scale (BSHS). The scale is composed of 114 items, based on the selection of items from a much larger pool by a group of professional and patient judges. The scale has been utilized to quantify dysfunction and distress across six major domains of health. Preliminary internal consistency and reliability testing of the scale has proved satisfactory. We present here the results of testing in 40 initial patients, with the following conclusions: 1) The psychosocial performance of patients with major burns lags behind their performance in other areas, and we need to explore alternate clinical strategies for their support; 2) The BSHS can be used to determine both individual and group performance and needs for intervention; 3) The postburn recovery is dynamic and undergoes marked changes for a prolonged period of time, at least 1 year post-hospitalization: this must be considered when such patients are being evaluated for various purposes, e.g., disability.

THE ANATOMIC APPROACH TO PULMONARY RESECTION

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