Intellectual profile and level of IQ among a clinical group of obese children and adolescents

This study explored intellectual profile of children attending a clinic for obesity and to what extent their characteristics predicted full scale IQ. Totally, 60 patients aged 8-16 years were recruited consecutively from the National Childhood Obesity Centre at Karolinska University Hospital in Sweden. These patients were tested using the Wechsler Intelligence Scale for Children (WISC). Of these 60 patients, 51 (85%) parents gave informed consent for their children's results to be included in this study (mean age 12.94, standard deviation, SD 2.42). The children's mean full scale IQ was 85.39. Parental education was strongly associated with child IQ. After adjustment for parental education, female gender and a higher level of obesity were associated with lower IQ. Obese children are at increased risk of having below average IQ and strategies to tackle associated problems should be developed in paediatric obesity clinics.

Family conditions and dietary control in phenylketonuria

OBJECTIVE

This investigation is an attempt to describe coping with phenylketonuria (PKU) in order to understand some aspects underlying good compliance.

METHODS

The coping concept was applied to PKU in two questionnaires. Self- and parental ratings were combined with assessments of phenylalanine levels and the severity of the disease. All Swedish patients with PKU born in 1980-91, a total of 53 children and youths with their parents, were invited to participate in the study and 41 (77%) of them did so.

RESULTS

The patients turned out to have good compliance with the diet. The main result was that patients with separated or divorced parents were more likely to have higher phenylalanine levels and this association was not diminished by adjustment for the potential confounding factors.

CONCLUSION

Patients' need for support must be judged individually according to different family conditions.

Morning versus bedtime isophane insulin in type 2 (non-insulin dependent) diabetes mellitus

Morning versus bedtime administration of NPH insulin was compared in 12 subjects with Type 2 diabetes and overt fasting hyperglycaemia. Subjects were studied at baseline (diet alone) and after 2 months on each of the two insulin programmes in a random crossover design, in which dosage was increased until at least one daily preprandial blood glucose was consistently in the range of 3.9 to 6.0 mmol l-1. Mean (+/- SEM) daily total insulin dosage was equivalent for the morning (0.36 +/- 0.03 units kg-1) and for the bedtime (0.37 +/- 0.03 units kg-1) insulin administration schedules. Glycaemic control was improved on both insulin regimens, but was better on bedtime than morning insulin. Fasting plasma glucose (mmol l-1) was 12.0 +/- 0.7 (baseline), 8.6 +/- 0.7 (morning), and 4.6 +/- 0.3 (bedtime), respectively. Mean 24 h plasma glucose (mmol l-1) was 13.3 +/- 1.3, 9.0 +/- 0.7, and 7.8 +/- 0.7. Glycated haemoglobin (%) was 7.65 +/- 0.35, 6.23 +/- 0.26, and 5.81 +/- 0.32. The improvement of basal glycaemia is a consequence of increased basal metabolic clearance of glucose (baseline, 47.6 +/- 3.1 ml m-2 min-1; morning 63.5 +/- 5.4, bedtime 103.5 +/- 7.1). There was no change in hepatic glucose output. It is concluded that bedtime administration of intermediate acting insulin results in increased basal insulinaemia, leading to improved basal glycaemia and consequent improved overall metabolic control, compared to morning insulin administration. Therefore, bedtime may be the preferable timing of insulin therapy for patients with Type 2 diabetes and overt fasting hyperglycaemia.

The use of acridine orange cytofluorometry in the study of macrophage lysosomal exocytosis

We present a rather simple cytofluorometric technique for the study of exocytosis of lysosomal contents from individual cultured cells. It is based on the use of the lysosomotropic weak base acridine orange (AO) which, in its stacked form, as it occurs within lysosomes, emits red fluorescence when excited by blue light. Mouse peritoneal macrophages were cultured for 48 h and, after 2 h in serum-free medium, stained with AO. The cells were then exposed to F10-medium with or without newborn calf serum (NCS), zymosan A (Z) or cytochalasin B (CB) for different times at 20 or 37 degrees C. After staining, the macrophages showed no change in red fluorescence intensity, if stored at room temperature in the dark. If, however, the cells were kept in the incubator at 37 degrees C, the cells showed slightly decreasing red fluorescence intensity with time. This decrease was markedly potentiated by the presence of NCS, Z or CB, which are known to induce secretion of lysosomal enzymes from macrophages in vitro. Selective lysosomal enzyme release was confirmed biochemically during treatment with zymosan A. The technique presented here may be of value in further studies on the stimulation of, and the mechanisms behind, lysosomal exocytosis in cultured cells.

Photooxidative damage to lysosomes of cultured macrophages by acridine orange

Cultured cells accumulate acridine orange (AO), which is a weak basic dye and a photosensitizer, in lysosomes and other acidic compartments. During exposure to blue light, AO-loaded macrophages show decreasing red granular fluorescence and increasing green diffuse fluorescence. This is hypothesized to represent peroxidative damage to lysosomal membranes resulting in an impaired proton gradient with deprotonation of the AO to its uncharged form and subsequent leakage of the dye. Further damage to the lysosomal membranes will result in release of lytic enzymes from the lysosomal compartment into the cytosol, leading to degeneration and finally cell death. The survival of AO-loaded and light-exposed macrophages is controllable by varying the exposure times to blue light. Inhibition of lysosomal proteases by E-64 results in increased cell survival after AO and blue light-mediated damage, indicating a role of proteolytic enzymes in this type of damage. Morphological analysis shows 'rounding up' with formation of retraction fibrils and pronounced plasma membrane blebbing. The formation of autophagic vacuoles is an early and pronounced event. After protease inhibition, however, all these phenomena are inhibitable to a considerable degree. We have thus directed photooxidative damage selectively to lysosomal membranes and their contents. This technique will allow further detailed studies of the role of lysosomes in degeneration-regeneration processes.

Lysosomal enzyme leakage during the hypoxanthine/xanthine oxidase reaction

Impairment of lysosomal stability due to reactive oxygen species generated during the oxidation of hypoxanthine by xanthine oxidase was studied in rat liver lysosomes isolated in a discontinuous Nycodenz gradient. Production of O2.- and H2O2 during the hypoxanthine/xanthine oxidase reaction occurred for at least 5 min, while lysosomal damage, indicated by the release of N-acetyl-beta-glucosaminidase, occurred within 30 s, there being no further damage to these organelles thereafter. The extent of lysosomal enzyme release increased with increasing xanthine oxidase concentration. Superoxide dismutase and catalase did not prevent lysosomal damage during the hypoxanthine/xanthine oxidase reaction. Lysosomes reduced xanthine oxidase activity, as assessed in terms of O2 consumption, only slightly but substantially inhibited in a competitive manner the O2.- -mediated reduction of cytochrome c. This inhibition was almost completely reversed by potassium cyanide, thus pointing to the presence of a cyanide-sensitive superoxide dismutase in the lysosomal fraction. However, potassium cyanide did not affect the hypoxanthine/xanthine oxidase-mediated lysosomal damage, thus suggesting an inability of the lysosomal superoxide dismutase to protect the organelles. Negligible malondialdehyde formation was observed in the lysosomes either during the hypoxanthine/xanthine oxidase reaction or with different selective experimental approaches known to produce lipid peroxidation in other organelles such as microsomes and mitochondria.(ABSTRACT TRUNCATED AT 250 WORDS)

Acridine orange-mediated photodamage of microsomal- and lysosomal fractions

Irradiation of microsomes with visible light in the presence of externally-added acridine orange results in O2 uptake, malondialdehyde accumulation, and inactivation of the microsomal drug-metabolizing system. The latter effect is reflected by a decrease in NADPH-cytochrome P450- and NADH-cytochrome b5 reductase activities and cytochromes P450 and b5 content by 88-, 85-, 60-, and 34%, respectively, after 5-min irradiation. Anoxia prevented inactivation of both reductases by 70-90%, whereas it prevented completely cytochrome b5 destruction. The presence of reducing equivalents, at the expense of NADPH and NADH, exert a partial protection (40-54% residual activities) against photosensitization damage on both reductase activities, whereas it almost fully protected cytochrome b5. Photosensitization of lipid peroxidation, as well as inactivation of the microsomal drug-metabolizing system, appears to involve both a type I and type II process. Products of lipid peroxidation might also play a role in enzyme inactivation and cytochrome destruction, as suggested by kinetic and time course studies and the redox state of microsomes. The uptake of acridine orange by isolated lysosomes is linearly dependent on the concentration of added dye and the distribution between extra- and intralysosomal acridine orange is strongly dependent on the amount of lysosomes. Irradiation of acridine orange-loaded lysosomes (light intensity at the sample position approximately 320 mW/cm2) produces an impairment of the membrane which leads to a rapid release of enzyme (N-acetyl-beta-glucosaminidase activity) into the medium, accompanied by a loss of activity in the lysosome-containing pellet and a partial photodamage of the enzyme. Concomitantly, thiobarbituric acid-reactive material accumulation increases in the reaction mixture with increasing irradiation time. When light intensity at the position was reduced to approximately 3.6 mW/cm2, photodamage of lysosomes was of a lesser magnitude, allowing the demonstration of a lag phase, which decreased with irradiation time, probably reflecting the so-called first-stage activation of lysosomes, preceding the release of lysosomal enzymes.

Evaluation of lysosomal stability in living cultured macrophages by cytofluorometry. Effect of silver lactate and hypotonic conditions

The ability of living mouse peritoneal macrophages to retain the lysosomotropic photosensitizer acridine orange (AO) within their secondary lysosomes was studied with a novel cytofluorometric method. During exposure to blue light, cellular AO fluorescence turned from a red granular pattern to that of diffuse green. The resulting change in total fluorescence intensity versus time - a primary decline due to red fluorescence bleaching and a secondary recovery due to the spectral shift - was interpreted as the result of leakage of AO from the lysosomal vacuome. The hypothesis that this time course should be affected by changes in lysosomal membrane stability was tested by labilizing the lysosomes by exposure of cultured macrophages to either hypotonic medium or silver lactate. In hypotonic medium, the ability to retain AO decreased continuously. Exposure to low concentrations of silver lactate (10 microM) also decreased AO retention time. We suggest that this method could be used, within appropriate experimental conditions, to evaluate lysosomal membrane stability in living cells.