Cognition and the risk of eating disorders in Spanish adolescents: the AVENA and AFINOS studies

Eating disorders (ED) can arise from a combination of biological and psychological factors. Some studies suggest that intellectual factors might be important in the development of ED, although the evidence is still scarce. The aim of this study was to examine the association between cognition measurements (cognitive performance and academic achievement) and the risk of developing ED in adolescents considering their weight status. The sample consisted of 3,307 adolescents (1,756 girls), aged 13-18.5 years, who participated in the AVENA (n = 1,430; 783 girls) and AFINOS (n = 1,877; 973 girls) studies. Cognitive performance was measured by the TEA test in the AVENA study, and academic achievement was self-reported in the AFINOS study. ED risk was evaluated in both studies by using the SCOFF questionnaire. Body mass index was calculated to classify adolescents as non-overweight or overweight (including obesity). Overweight adolescents showed a higher risk of developing ED than non-overweight ones in both studies. In the AVENA study, overweight boys with low performance in reasoning ability showed increased risk of ED (p = 0.05). In the AFINOS study, overweight boys with low academic performance in physical education and non-overweight girls with low academic achievement in all the areas analyzed showed higher risk of ED than their peers (all p < 0.05).

CONCLUSION

No association between cognitive performance and ED risk was found in adolescents, while academic achievement was associated with ED risk, especially in non-overweight girls. The non-cognitive traits that accompany academic achievement could influence the likelihood of developing ED in these girls.

Five year trends on total and abdominal adiposity in Spanish adolescents

OBJECTIVE

To assess five years trends in total and abdominal fat in Spanish adolescents.

DESIGN

Two cross-sectional studies: adolescents from the city of Zaragoza (Spain) assessed during 2001-2002 and 2006-2007.

SUBJECTS

399 adolescents in 2001-02 and 392 adolescents in 2006-07.

MAIN OUTCOME MEASUREMENTS

Socio-economic status was assessed using the education level of both parents. A complete anthropometric assessment was performed in both surveys using the same methodology: weight, height, skinfold thickness (biceps, triceps, subscapular, suprailiac, thigh and calf) and circumferences (waist and hip). The body mass index (BMI) and the sum of 6 skinfold thicknesses were calculated. Body fat percentage (BF%) was also calculated by the formulas described by Slaughter et al.

RESULTS

After adjusting for age and pubertal status, only females showed a significantly decrease in weight, BMI and waist circumference, and a significant increase in the sum of 6 skinfolds (all P < 0.05 and Cohen's d ≥ 0.25) in 2006-2007, when compared to values obtained in 2001-2002. Males did not show any significant change between the two surveys. Concerning centile values, a slight general reduction was observed in weight, BMI and waist circumference for both males and females. On the contrary, the sum of 6 skinfolds and the BF% were higher in 2006-2007 than in 2001-2002.

CONCLUSION

According to these results, there might be a levelling-off in the trends of BMI, BF% and waist circumference in male adolescents from Zaragoza. In females, despite a trend towards higher body fat mass, there was a trend towards lower BMI and waist circumference values.

Nutrition and physical activity programs for obesity treatment (PRONAF study): methodological approach of the project

BACKGROUND

At present, scientific consensus exists on the multifactorial etiopatogenia of obesity. Both professionals and researchers agree that treatment must also have a multifactorial approach, including diet, physical activity, pharmacology and/or surgical treatment. These two last ones should be reserved for those cases of morbid obesities or in case of failure of the previous ones. The aim of the PRONAF study is to determine what type of exercise combined with caloric restriction is the most appropriate to be included in overweigth and obesity intervention programs, and the aim of this paper is to describe the design and the evaluation methods used to carry out the PRONAF study.

METHODS/DESIGN

One-hundred nineteen overweight (46 males) and 120 obese (61 males) subjects aged 18-50 years were randomly assigned to a strength training group, an endurance training group, a combined strength + endurance training group or a diet and physical activity recommendations group. The intervention period was 22 weeks (in all cases 3 times/wk of training for 22 weeks and 2 weeks for pre and post evaluation). All subjects followed a hypocaloric diet (25-30% less energy intake than the daily energy expenditure estimated by accelerometry). 29-34% of the total energy intake came from fat, 14-20% from protein, and 50-55% from carbohydrates. The mayor outcome variables assesed were, biochemical and inflamatory markers, body composition, energy balance, physical fitness, nutritional habits, genetic profile and quality of life. 180 (75.3%) subjects finished the study, with a dropout rate of 24.7%. Dropout reasons included: personal reasons 17 (28.8%), low adherence to exercise 3 (5.1%), low adherence to diet 6 (10.2%), job change 6 (10.2%), and lost interest 27 (45.8%).

DISCUSSION

Feasibility of the study has been proven, with a low dropout rate which corresponds to the estimated sample size. Transfer of knowledge is foreseen as a spin-off, in order that overweight and obese subjects can benefit from the results. The aim is to transfer it to sports centres. Effectiveness on individual health-related parameter in order to determine the most effective training programme will be analysed in forthcoming publications.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01116856.

Interplay between weight loss and gut microbiota composition in overweight adolescents

The aim of this study was to determine the influence of an obesity treatment program on the gut microbiota and body weight of overweight adolescents. Thirty-six adolescents (13-15 years), classified as overweight according to the International Obesity Task Force BMI criteria, were submitted to a calorie-restricted diet (10-40%) and increased physical activity (15-23 kcal/kg body weight/week) program over 10 weeks. Gut bacterial groups were analyzed by quantitative real-time PCR before and after the intervention. A group of subjects (n=23) experienced >4.0 kg weight loss and showed significant BMI (P=0.030) and BMI z-score (P=0.035) reductions after the intervention, while the other group (n=13) showed <2.0 kg weight loss. No significant differences in dietary intake were found between both groups. In the whole adolescent population, the intervention led to increased Bacteroides fragilis group (P=0.001) and Lactobacillus group (P=0.030) counts, and to decreased Clostridium coccoides group (P=0.028), Bifidobacterium longum (P=0.031), and Bifidobacterium adolescentis (P=0.044) counts. In the high weight-loss group, B. fragilis group and Lactobacillus group counts also increased (P=0.001 and P=0.007, respectively), whereas C. coccoides group and B. longum counts decreased (P=0.001 and P=0.044, respectively) after the intervention. Total bacteria, B. fragilis group and Clostridium leptum group, and Bifidobacterium catenulatum group counts were significantly higher (P<0.001-0.036) while levels of C. coccoides group, Lactobacillus group, Bifidobacterium, Bifidobacterium breve, and Bifidobacterium bifidum were significantly lower (P<0.001-0.008) in the high weight-loss group than in the low weight-loss group before and after the intervention. These findings indicate that calorie restriction and physical activity have an impact on gut microbiota composition related to body weight loss, which also seem to be influenced by the individual's microbiota.

Truncal and abdominal fat as determinants of high triglycerides and low HDL-cholesterol in adolescents

We examined whether abdominal and truncal adiposity, assessed with simple anthropometric indices, determines serum triglycerides and high-density lipoprotein (HDL)-cholesterol levels independently of total adiposity amount in adolescents. A total of 547 Spanish adolescents (284 males and 263 females) aged 13-18.5 years were included in this study. Measures of truncal adiposity included subscapular to triceps ratio, and trunk-to-total skinfolds ratio (TTS%). Waist circumference was used as a surrogate of abdominal adiposity, and BMI was used as a measure of total adiposity. The results of the regression models indicated that levels of triglycerides were positively associated with waist circumference and TTS% after controlling for age and Tanner stage in both sexes. Once BMI was entered in the model, these associations remained significant for waist circumference in females. HDL-cholesterol levels were negatively associated with waist circumference in both sexes, and with subscapular to triceps ratio and TTS% in males, after controlling for age and Tanner stage. Once BMI was entered in the model, these associations remained significant for subscapular to triceps ratio and for TTS% in males. The results of this study suggest that in male adolescents, truncal adiposity is negatively associated with levels of HDL-cholesterol, whereas in females, abdominal adiposity is positively associated with levels of triglycerides independently of total adiposity. These findings highlight the deleterious effect of both truncal and abdominal fat depots on the lipid profile already from the first decades of life.

Effect of the Ala12 allele in the PPARgamma-2 gene on the relationship between birth weight and body composition in adolescents: the AVENA study

The intent of this study was to assess whether the effect of birth weight on later body composition is modified by Pro12Pro, Pro12Ala, and Ala12Ala genotypes of the peroxisome proliferator-activated receptor gamma-2 (PPARgamma-2) gene. The PPARgamma-2 gene polymorphism was genotyped in 273 adolescents aged 13-18.5 y, born at term and whose birth weight was known. They were selected from a cross-sectional multicenter study conducted in five Spanish cities in 2000-2002. Body mass index (BMI) was calculated from weight and height measurements, and body composition and fat distribution were estimated from skinfold thickness. A total of 229 subjects (111 males and 118 females) carried the Pro12Pro genotype and 44 (22 males and 22 females) the Pro12Ala and Ala12Ala PPARgamma-2 genotypes. In the Pro12Pro group, birth weight Z score was positively associated with both fat-free mass (FFM) (p < 0.05) and fat mass (FM) (p < 0.05), but these relationships disappeared after controlling for age, gestational age, socioeconomic status (SES), physical activity, Tanner stage, sex, and BMI. In the Ala12 group, birth weight Z score was positively associated with FFM (p < 0.01), and this relationship remained significant after controlling for confounding variables (p < 0.05). Small body weight at birth may program lower FFM in adolescents carrying the Ala12 allele in the PPARgamma-2 gene.

[Lipid and metabolic profiles in adolescents are affected more by physical fitness than physical activity (AVENA study)]

INTRODUCTION AND OBJECTIVES

To determine whether the level of physical activity or physical fitness (i.e., aerobic capacity and muscle strength) in Spanish adolescents influences lipid and metabolic profiles.

METHODS

From a total of 2859 Spanish adolescents (age 13.0-18.5 years) taking part in the AVENA (Alimentación y Valoración del Estado Nutricional en Adolescentes) study, 460 (248 male, 212 female) were randomly selected for blood analysis. Their level of physical activity was determined by questionnaire. Aerobic capacity was assessed using the Course-Navette test. Muscle strength was evaluated using manual dynamometry, the long jump test, and the flexed arm hang test. A lipid-metabolic cardiovascular risk index was derived from the levels of triglycerides, low-density lipoprotein cholesterol (LDLC), high-density lipoprotein cholesterol (HDLC), and glucose.

RESULTS

No relationship was found between the level of physical activity and lipid-metabolic index in either sex. In contrast, there was an inverse relationship between the lipid-metabolic index and aerobic capacity in males (P=.003) after adjustment for physical activity level and muscle strength. In females, a favorable lipid-metabolic index was associated with greater muscle strength (P=.048) after adjustment for aerobic capacity.

CONCLUSIONS

These results indicate that, in adolescents, physical fitness, and not physical activity, is related to lipid and metabolic cardiovascular risk. Higher aerobic capacity in males and greater muscle strength in females were associated with lower lipid and metabolic risk factors for cardiovascular disease.

Brain docosahexaenoic acid status and learning in young rats submitted to dietary long-chain polyunsaturated fatty acid deficiency and supplementation limited to lactation

N-3 fatty acid deficiency has been related to decreased docosahexaenoic acid (DHA) and increased docosapentaenoic acid (DPA) levels in brain and to learning disadvantages. The influence of n-3 deficiency and supplementation on brain fatty acids and learning were investigated in young rats. Newborn Wistar rats were assigned to three groups of cross-foster mothers. The control group (C) was nursed by mothers that received essential fatty acids during pregnancy and lactation, and the deficient group (D) was nursed by mothers that did not receive those fatty acids. The supplemental group (S) had the same conditions as D, receiving an additional DHA and arachidonic acid supplement during lactation. Cerebral cortex and hippocampus fatty acid composition was examined using thin-layer and capillary column gas chromatography, and learning was measured by passive-avoidance procedure. D brains showed low DHA and high DPA levels, but S brain composition was similar to C. Learning in the S group was unaffected, but in the D group, it was poorer than C. Learning was directly correlated with DHA levels and inversely with DPA levels in brain. Low DHA and high DPA brain levels both were correlated with poor learning. DPA seems not to be a suitable brain functional analogue of DHA, and DHA supplementation reversed both biochemical and learning adverse effects observed in n-3 deficiency.

Breast-feeding and risk of hospitalization for all causes and fever of unknown origin

BACKGROUND

Breast-feeding has shown to give a reduction in the risk of hospitalization due to respiratory tract infections and gastrointestinal conditions during the first two years of life. The association of breast-feeding with all admission causes and with fever of unknown origin (FUO) was analysed.

METHODS

A case-reference study in Cantabria (northern Spain) was carried out. Cases (n=336) were hospitalized children aged less than 24 months at University of Cantabria Hospital; the reference was a 1:1 matched (by time from delivery to admission) sample of children from mothers delivering at the same hospital. Information on breast-feeding, socioeconomic variables and employment were obtained. Odds ratios (ORs), their 95% confidence intervals (CIs), and mean length of breast-feeding were estimated after adjusment for confounding variables.

RESULTS

In the reference population, shorter duration of breast-feeding was associated with smoking, lower educational level, and less privileged social strata. The frequency of breast-feeding was higher in the reference than in the cases, 82.3% vs 75.6% (p=0.023). Significant negative trends were noted in univariate analyses between the length of breast-feeding and both all admission causes and FUO, although the statistical significance was lost after adjusting for confounding variables (educational level, social class, smoking, and use of incubator after delivery). The adjusted mean length of breast-feeding was shorter in hospitalized children < or = 6 months old for both all admission causes (40.6 +/- 5.4 vs 99.5 +/- 5.4, p < 0.001) and FUO (40.8 +/- 12.4 vs 91.7 +/- 12.4, p=0.006).

CONCLUSION

Breast-feeding time is shorter in hospitalized children for both all admission causes and FUO.

Expression and regulation of the transcriptional repressor ZNF43 in Ewing sarcoma cells

In vitro, cells derived from Ewing sarcoma (ES) with the characteristic somatic rearrangement between the genes EWS and FLII can be induced to differentiate toward a neuronal phenotype by exposure to agents such as dibutyryl cyclic AMP (db cAMP) or retinoic acid. Therefore, expression of the chimeric Ews-Flil protein does not irreversibly block the capacity of Ewing cells to engage in the neuronal differentiation program initiated by these agents. To identify genes that might be involved in the maintenance of Ewing cells in their undifferentiated state, a PCR-based differential display method was used to compare gene expression patterns in Ewing cell lines with those induced to differentiate toward a neuronal phenotype. A cDNA was expressed at high levels in proliferating Ewing-derived EW-1 cells and downregulated in EW-1 cells induced to differentiate, which corresponds to ZNF43, a multi-zinc finger protein containing the Krüppel-associated box (KRAB) transcriptional repression domain. Treatment of EW-1 cells with antisense oligonucleotides complementary to ZNF43 mRNA induces morphological differentiation and growth arrest. These findings suggest a role for ZNF43 in the maintenance of ES cells in an undifferentiated state, and that ZNF43 could be a primary target for differentiation stimuli in Ewing cells.

Apolipoprotein C-III and E polymorphisms and cardiovascular syndrome, hyperlipidemia, and insulin resistance in renal transplantation

Hyperlipidemia and insulin resistance frequently develop after renal transplantation, contributing to cardiovascular disease. Individual differences in response based upon genetic variations in proteins regulating lipidic and glucose tolerance metabolism could be expected. In the general population, the S2 allelic variant of the apoprotein (apo) C-III gene has been associated with hypertriglyceridemia and an insulin resistant state, whereas the E4 allele of the apo E has been associated with hypercholesterolemia and atherosclerosis. Its influence in renal transplant patients remains to be seen. In order to assess the impact of apo E and C-III major polymorphisms on atherosclerotic vascular disease, lipid profile and impaired glucose tolerance in renal transplant patients, we studied 110 consecutively examined patients undergoing kidney transplantation (age range 24-73 years). Atherosclerotic complications were detected in 25% of patients, with age, male sex and hypercholesterolemia being significant atherosclerotic risk factors. Among the male patients with E4 allele, the odds ratio for coronary disease and global atherosclerosis were 10.2 (95% CI) and 6.4 (95% CI), respectively. There were no significant differences in the frequency of any of the polymorphisms among patients with dyslipidemia and impaired glucose tolerance. As the number of patients in our sample was small, larger studies are needed to verify these issues. While in the studied population C-III polymorphism appears to have little association with the prevalence of atherosclerotic complications, E4 allele should be considered as a genetic marker of coronary artery disease and global atherosclerosis in renal transplant patients.

Long-chain polyunsaturated fatty acids in rat maternal milk, offspring brain and peripheral tissues in essential fatty acid deficiency

Fatty acid status in humans is usually related to plasma or red blood cell fatty acid profiles. The aim of the study was to explore whether a maternal deficiency in dietary essential fatty acids would differentially affect lipid fractions in several tissues of the offspring, including brain. Female Wistar rats were fed an essential fatty acid-deficient diet during 3 months before mating. The fatty acid composition of different lipid fractions was examined in maternal milk, and in plasma, red blood cells, liver, adipose tissue, cerebral cortex and hippocampus of the offspring using thin layer and capillary column gas chromatography. Lipid fractions from most tissues of deprived offspring showed a common fatty acid profile characterized by elevated 20:3 omega9/20:4 omega6 ratio, and decreased docosahexaenoic acid and arachidonic acid. However, arachidonic acid was not affected in brain, even though 22:5 omega6 was increased in phospholipids of cerebral cortex and hippocampus. The present results demonstrate different degrees of resistance to essential fatty acid deficiency in lipid fractions and tissues. This suggests a priority distribution of arachidonic acid to preferential areas and shows that blood phospholipid fatty acids do not exactly reflect brain phospholipid status.

Cutaneous vasculitis in children and adults. Associated diseases and etiologic factors in 303 patients

Cutaneous vasculitis (CV), a condition characterized by palpable purpura and nonspecific histopathologic findings, presents a diagnostic and therapeutic challenge because it may be a primary disorder or it may be a cutaneous manifestation of another entity, such as systemic necrotizing vasculitis, connective tissue disease, systemic bacterial infection, or malignancy. We studied 303 unselected patients (172 adults and 131 children) with CV to assess the disease associations and etiologic factors, to identify the frequency of primary and secondary CV in different age-groups, and to characterize features that help to distinguish between primary and secondary CV. Of the 131 children, 130 had primary CV: Henoch-Schönlein purpura (HSP) in 116 and hypersensitivity vasculitis (HV) in 14. In contrast, of the 172 adults, only 120 had primary CV: HSP in 39, HV in 70, and essential mixed cryoglobulinemia in 11. CV was a manifestation of systemic necrotizing vasculitis in 23 adults (polyarteritis nodosa in 17, Wegener granulomatosis in 4, and Churg-Strauss syndrome in 2). CV was secondary to other processes in 29 adults: in 20 patients CV was associated with connective tissue disease or another autoimmune or rheumatic disease, in 5 patients CV was a manifestation of severe bacterial infection, especially bacterial endocarditis (4 cases), and in the other 4 patients CV was the presenting symptom of an underlying malignancy. The patients for whom CV was a manifestation of systemic necrotizing vasculitis or secondary to a connective tissue disease, severe bacterial infection, or malignancy had clinical and laboratory data suggestive of the associated disorder. The clinical picture and outcome of primary CV in both children and adults were benign. By contrast, the prognosis of patients with CV in the context of systemic necrotizing vasculitis or secondary to other entities depended on the primary process. Given the different disease association in children and adults, we propose a simple diagnostic workup in children with CV. By contrast the diagnostic approach in adults with CV should be more cautious and the workup more extensive. The early differentiation between primary CV, secondary CV, and CV presenting as a symptom of systemic necrotizing vasculitis, especially in adults, is of paramount importance for an adequate diagnosis and appropriate treatment.

PI SZ phenotype in chronic obstructive pulmonary disease

BACKGROUND

A study was undertaken to clarify whether the PI SZ phenotype of the protease inhibitor system predisposes to chronic obstructive pulmonary disease (COPD).

METHODS

The prevalence of PI Z and PI SZ deficient phenotypes was investigated in a population of 702 patients with COPD followed up at the Chest Unit of a tertiary hospital and in 15400 newborn infants from the same geographical area. Individuals with deficiency were detected by screening of dried blood spots on filter paper using a comparative electro-immunodiffusion technique for alpha 1-antitrypsin and transferrin. The serum phenotype was confirmed by means of isoelectrofocusing on polyacrylamide gel.

RESULTS

Of the 702 blood samples from patients with COPD, six PI Z subjects (0.85%) and one PI SZ (0.14%) were detected. Of the 15400 samples from neonates, the number of PI Z subjects was eight (0.052%) and that of PI SZ was 24 (0.156%). The difference between the two groups was significant for PI Z but not for PI SZ.

CONCLUSIONS

The data do not indicate an increased risk for development of COPD associated with the PI SZ phenotype but confirm the predisposition of PI Z individuals for the development of COPD.

Henoch-Schönlein purpura in adulthood and childhood: two different expressions of the same syndrome

OBJECTIVE

To assess the possible differences between children (< or = 20 years) and adults (> 20 years) with Henoch-Schönlein purpura (HSP).

METHODS

A retrospective study of an unselected population of patients with HSP who presented to our teaching hospital between 1975 and 1994. Patients were classified as having HSP according to the criteria proposed by Michel et al.

RESULTS

Following the above-mentioned criteria, 162 white patients (113 male and 49 female) were classified as having HSP; 46 of the patients were adults (mean +/- SD age 53.2 +/- 16.9 years) and 116 were children (6.9 +/- 3.1 years). We were unable to identify any precipitating event in 72% of the adults and 66% of the children. The frequency of previous drug treatment, primarily antibiotics or analgesics, was similar in both groups, whereas previous upper respiratory tract infection was more frequent among the children (P < 0.02). At symptom onset, cutaneous lesions were the main clinical manifestation in both groups. However, adults had a lower frequency of abdominal pain (P < 0.008) and fever (P < 0.01), and a higher frequency of joint symptoms (P < 0.001). During the clinical course, adults had more frequent (P < 0.001) and severe renal involvement. An increased erythrocyte sedimentation rate was also more frequent in the adults (P < 0.001). Adults required more aggressive therapy, consisting of steroids (P < 0.002) and/or cytotoxic agents (P < 0.001). The outcome was relatively good in both age groups, with complete recovery in 107 children (93.9%) and in 33 adults (89.2%) after a mean +/- SD followup of 19.4 +/- 27.7 (median 12) and 21.8 +/- 33.5 (median 15) months, respectively.

CONCLUSION

In adulthood, HSP, as defined by the criteria proposed by Michel et al, represents a more severe clinical syndrome, with a higher frequency of renal involvement. However, the final outcome of HSP is equally good in patients of both age groups.

[Blood coagulation, genetics and post-angioplasty restenosis]

Throughout the last few decades, different factors have been related to coronary stenosis which is clinically evidenced by coronary heart disease, the leading cause of death in developed countries. Different experimental models have contributed towards defining some of these factors, and to an understanding of the physiopathology of the atherosclerotic lesion. The genetic basis related to individual responses to the same event is currently being established. As endothelial injury reparative mechanisms are fundamental in atherosclerosis pathogeny, patients who experiment restenosis after undergoing revascularization procedures are useful human models in the study of these processes. We review from the literature the genetic factors related to thrombus formation, which may be associated with restenosis after percutaneous transluminal coronary angioplasty, in order to define the most suitable anticoagulant therapy for each patient. We refer to the recently characterized gene for the platelet receptors and its relationship with fibrinogenous, factor Xa, PAI-I, and the involvement of apolipoprotein (a) in the coagulation process.

Hypomagnesaemia of hereditary renal origin

Cases of hypomagnesaemia of hereditary renal origin represent at least three different congenital disorders of tubular reabsorption of magnesium (Mg). Isolated familial hypomagnesaemia has been reported in a heterogeneous group of patients and an autosomal dominant pattern of inheritance has often been found to be present. Familial hypokalaemia-hypomagnesaemia, inherited as an autosomal recessive trait, has been reported in 17 patients and we now describe 3 additional cases. Hypomagnesaemia is accompanied by hypokalaemia, metabolic alkalosis, hypocalciuria and moderate sodium chloride wasting. Titration of renal Mg reabsorption indicates the presence of a low threshold but a normal Tm. The inherited defect is probably situated at the level of the distal convoluted tubule and mimics the therapeutic effect of thiazides. This condition is frequently confused with Bartter's syndrome. Familial hypomagnesaemia-hypercalciuria, also inherited as an autosomal recessive trait, has been reported in at least 15 patients and we now add 3 new cases. Hypomagnesaemia is always accompanied by hypercalciuria and nephrocalcinosis. Ocular abnormalities such as myopia and horizontal nystagmus are often present. Hypermagnesiuria is of a greater degree than that observed in the previous entity and reflects a low Tm of Mg reabsorption. The defect must be situated at the level of the ascending limb of the loop of Henle and affects the transport of both calcium and Mg but not of sodium and chloride. This condition has not been clearly separated from hereditary distal renal tubular acidosis in the literature.

Immunoglobulin-producing cells in IgA nephropathy

The number of peripheral blood mononuclear cells (PBMC) producing IgA, IgG and IgM spontaneously, after in vitro polyclonal stimulation with pokeweek mitogen (PWM) and in response to autologous mixed lymphocyte reaction (AMLR), were determined by a protein A hemolytic plaque assay in 23 patients with IgA nephropathy confirmed by renal biopsies and in 24 normal controls. The geometric mean of circulating IgA-producing cells in Berger's disease (689 +/- 1.73 cells/10(6) PBMC) was increased when compared with the normal controls (332 X divided by 1.52 cells/10(6) PBMC; p less than 0.001). To a lesser degree, there was also an increase in the number of IgG-secreting cells (98 +/- 3.97 cells/10(6) PBMC vs. 38 +/- 2.90 cells/10(6) PBMC; p less than 0.05). After PWM stimulation, although the number of IgA-producing cells was increased in patients with IgA nephropathy, no significant differences were observed between the 2 groups. In response to AMLR, the number of IgA-secreting cells was significantly higher in the cases with Berger's disease (1,979 +/- 1.76 cells/10(6) non-T cells vs. 783 +/- 1.95 cells/10(6) non-T cells; p less than 0.001). Although it did not reach statistical significance, the patient group had also an increase in the number of IgG-producing cells (884 +/- 2.64 cells/10(6) non-T cells vs. 317 +/- 5.05 cells/10(6) non-T cells). These data support the existence of some abnormalities in the mechanisms regulating the synthesis of IgA in Berger's disease which might contribute to its pathogenesis.

[Poststreptococcal glomerulonephritis]

Acute poststreptococcal glomerulonephritis is one of the best defined renal diseases and it is the commonest form of acute glomerulonephritis in children. Antigen-antibody complexes formed in the circulation or "in situ" seem to play an important role in the pathogenesis and even though antiglobulins have recently been incriminated, there is still controversy over the nature of the antigen/s involved. Usually the clinical picture is very characteristic, but in those cases of atypical presentation mainly in those without urinary abnormalities, the diagnosis could be resolved by demonstration of well defined histological lesions. Although it is generally agreed upon, on the basis of clinical observations, that recovery from acute glomerulonephritis generally occurs in children, confusion still exists concerning the precise frequency with which chronicity may happen in this disease. There is no specific treatment for the immunological processes but symptomatic therapy has considerably reduced early mortality.

Serum levels of alpha 1-antitrypsin and Pi types in children with bronchiolitis

Alpha 1-antitrypsin levels were determined at the beginning of the disease and after clinical recovery in a group of 51 infants with bronchiolitis, and the results were compared to those obtained in 24 normal infants and in 15 infants with viral bronchopneumonia. Distribution of Pi types in the patients with bronchiolitis was also compared to that observed in a control population of 170 blood donors of the same ethnic background. Both serum levels of alpha 1-antitrypsin and prevalence of non-M phenotypes were not statistically different from the values found in the control groups, thus not supporting the hypothesis that a deficiency of alpha 1-antitrypsin plays a role in the pathogenesis of bronchiolitis. A non explained finding was the lack of elevation of serum level of alpha 1-antitrypsin during the acute phase of the bronchiolitis process, a fact present in the group of patients with bronchopneumonia.