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A Ballabriga

Publications and source records attributed to A Ballabriga.

At least 19 recordsLinked to original sources
PubMed2000

Morphological and physiological changes during growth: an update.

Skeletal growth and changes in body composition during growth present important variations; body mass index and lean body mass related to age show important gender differences. The process of ossification is developed in two different ways, endochondral and intramembraneous. The former is characterised by the formation of bone from growth cartilage. Intramembraneous ossification is characterised by the formation of bone from a mesenchymal structure, as occurs with the flat bones of the skull. During childhood and adolescence and up to the acquisition of adult stature, two phenomenons are produced simultaneously: the synthesis of new bone from growth cartilage due to the process of endochondral ossification, and modeling-remodeling of previously synthesized bone. Bone growth and mineralisation of its extracellular matrix are simultaneous phenomenons, the final result being the acquisition and maintenance of body bone mass. A positive calcium balance is necessary during adolescence in order to achieve the maximum peak of bone mass and even with the termination of longitudinal growth of bone, the process of mineralisation can last a further 4 years. Childhood and adolescence are the period of life in which the peak of bone mass must be achieved, and if during this time this does not happen there will be a greater risk for the later development of osteoporosis. Regulation of bone mass is a polygenic process and during recent years studies have been centred on the receptor genes of vitamin D and estrogens. A maximum calcium retention during adolescence may influence the achievement of a high peak of bone mass but at a certain level of calcium intake the calcium retention reaches a plateau. The expression of grams of hydroxyapatite per square centimetre has been used clinically, or expressed in volume as g/cm3. From birth until 3 years, the increase represents approximately 30% of the total increase, from 3 years until the beginning of pubertal development the increase is 20%. During pubertal development there is an increase of 30-40% and from the end of growth until the age of 21 years there is an increase of 15-20%. Both prepubertal boys and girls show a progressive increase of leptin levels during the years prior to the onset of puberty and until Tanner's stage 11 and higher levels are observed in girls in this period, possibly in relation to their earlier onset of puberty. This increase of leptin in girls during pubertal development suggests that leptin may be a link between adipose tissue and puberty.

Adolescent↗
PubMed1998

Lead exposure in the general population of the Metropolitan Area of Barcelona: blood levels and related factors.

A cross-sectional study was conducted on 254 individuals not occupationally exposed to lead to determine the degree of lead exposure in the general population of the Metropolitan Area of Barcelona. Blood lead levels (BPb) were analysed by atomic absorption spectrophotometry and zinc protoporphyrin (ZPP) by haemofluorimetry. Blood lead levels were analysed with respect to individuals' age, sex, area of residence, the season of the year the blood was drawn and ZPP. Mean blood lead in our series was 0.22 +/- 0.011 mumol/l (mean +/- S.E.); no significant differences were found with respect to area of residence, sex or season. A linear relationship was observed between BPb and individuals' age (BPb = 0.08 + 0.05 x age; r = 0.37). The prevalence of lead intoxication (BPb > 0.48 mumol/l) was 7.1%. No linear relationship was observed between BPb and ZPP. ZPP determination does not appear to be a good screening method for lead intoxication since it presents low specificity and sensitivity values with an area below the ROC curve similar to the null value line (area below the curve = 0.5052, IC 95% = 0.443-0.568). We conclude that lead exposure does not constitute a serious health problem in the area studied, since BPb levels found are far below the toxic limit and the prevalence of intoxication is similar to that reported in other studies conducted in other developed countries.

Adolescent↗
PubMed1998

Lead exposure in children: levels in blood, prevalence of intoxication and related factors.

Lead is a highly toxic metal, the main source of which is contamination from combustion of unleaded petrol. The aims of this work were to detect the degree of lead exposure in a large sample of children; determine the relationship between blood lead levels (BPb) and age, sex, habitat and season of the year; and correlate BPb with zinc protoporphyrin (ZPP) values. A cross-sectional study was carried out. Blood from routine extractions drawn at our centre was used. BPb and ZPP were measured by atomic absorption spectrophotometry and haematofluorimetry, respectively. We analysed 1158 blood samples from children. BPb (mean +/- SEM): 0.22 +/- 0.04 mumol l-1. Correlation BPb-age: BPb = 0.19 + 0.086 x age (months), r = 0.129, P < 0.0001. BPb was greater in boys (0.23 +/- 0.007 versus 0.20 +/- 0.006 mumol l-1, P < 0.0002). No differences were observed between habitats (urban versus rural). BPb were higher in the warm months (0.24 +/- 0.013 versus 0.21 +/- 0.007 mumol l-1, P < 0.0001). Prevalence of lead intoxication (BPb > 0.48 mumol l-1) was 4.2%. No differences in prevalence were found among the different groups. The correlation between BPb and ZPP showed r = 0.0969, P = 0.0024. Utility for screening: sensitivity of 53.7% and specificity of 59.3% (cut-off point of 60 mumol ZPP mol-1 haem). We can conclude that lead exposure in children in our sample was in the range reported in similar studies in other areas and countries, and below the toxic limit. None of the factors analysed significantly influenced lead intoxication prevalence. There was no good correlation between ZPP and BPb in our samples and the ZPP cut-off point used did not present good specificity and sensitivity values.

Age Factors↗
PubMed1994

Blood polyunsaturated fatty acids in patients with peroxisomal disorders. A multicenter study.

The purpose of the study was to compare the polyunsaturated fatty acid (PUFA) status in patients with X-linked adrenoleukodystrophy or adrenomyeloneuropathy (X-ALD/AMN) with that in disorders of peroxisome biogenesis (PB). Total fatty acids and plasmalogens were quantified in plasma and red cells from 28 patients with X-ALD/AMN, 26 patients with generalized peroxisomal disorders, and 37 controls. Total fatty acid methyl esters and plasmalogen dimethyl acetals were obtained by direct transmethylation and separated by capillary column gas chromatography. The results confirm previous findings in that docosahexaenoic acid (DHA, 22:6n-3) was greatly decreased in both plasma and erythrocytes from patients with PB disorders. When nutritional conditions were adequate, patients with X-ALD/AMN had normal levels of DHA. A highly significant positive correlation was found between the levels of DHA and those of plasmalogens in peroxisomal patients. As in other tissues, the parent n-6 fatty acid, linoleic acid (LA, 18:2n-6) was significantly increased in red cells from PB patients, whereas arachidonic acid (20:4n-6) was virtually within normal limits. In clear contrast to red cells and other tissues, arachidonate was significantly lower in plasma from PB patients. The decrease in plasma arachidonate and the high tissue levels of LA suggest a defect of delta 6 desaturase and/or delta 5 desaturase in PB patients. The n-6 fatty acids were normal in X-ALD/AMN patients. The present data show that X-ALD/AMN patients do not have the profound PUFA alterations that PB patients have, at least in blood.

Adolescent↗
PubMed1994

Aluminum in the neonate related to parenteral nutrition.

Sources of aluminium loading and exposure in preterm and full-term newborns were studied. Parenteral nutrition solutions were the main source of aluminium representing 88.7% of total aluminium intake. Blood and urine aluminium levels were followed over a 28-day period in a group of 26 preterm and 9 term infants while receiving parenteral nutrition (duration 15.6 +/- 8.7 days) and later when being formula fed. Urine levels were followed up to 13 weeks in a subgroup of the neonates. Serum aluminium levels (0.86 +/- 0.38 mumol/l) and urine aluminium/creatinine ratio (1.52 +/- 0.81 mumol/mmol) were increased when the infants were receiving parenteral nutrition compared with the control group (p < 0.001). The urine aluminium/creatinine ratio remained high up to 10 weeks following withdrawal of parenteral nutrition and suggested tissular loading. This was confirmed after high aluminium levels were found in post-mortem brain and bone samples from two preterm and one full-term infant. We conclude that both preterm and full-term neonates are susceptible to accumulation of aluminium in tissue while receiving parenteral nutrition.

Aluminum↗
PubMed1992

Somatostatin effects on cultured human fetal epiphyseal chondrocytes.

Somatostatin effects on cultured human fetal epiphyseal chondrocytes were evaluated by studying the effects of somatostatin on DNA synthesis. Cultured epiphyseal chondrocytes from human fetuses (12-40 wk old) were incubated for 48 h in Ham's F-12 serum-free medium. After this, the medium was replaced by MCDB-104 serum-free medium and the cells were incubated for an additional 48 h in the presence or absence of somatostatin 1 pM to 10 microM, with the addition of 3H-thymidine (5 microCi/mL) for the last 24 h of incubation. A significant (p < 0.02) inhibitory effect of somatostatin (1 nM to 10 microM) on 3H-thymidine DNA incorporation was observed in cultured chondrocytes from fetuses of all gestational ages studied (12-40 wk), with no significant differences among fetal ages. In conclusion, our results show that somatostatin exerts a biologic effect on cultured human fetal epiphyseal chondrocytes, as it does in its target cells. These results suggest that somatostatin could regulate human skeletal growth not only by growth hormone secretion regulation, but also by acting directly on chondrocyte metabolism. However, the physiologic significance of the latter remains to be elucidated.

Cells, Cultured↗
PubMed1992

Effects of triiodothyronine (T3) and identification of specific nuclear T3-binding sites in cultured human fetal epiphyseal chondrocytes.

The effects of T3 on cultured human fetal epiphyseal chondrocytes were assessed by studying its effects on DNA synthesis and alkaline phosphatase activity. DNA synthesis was evaluated as follows: after 48-h incubation in Ham's F-12 serum-free medium, cultured chondrocytes were incubated with or without T3 (0.1-100 nM) in MCDB-104 serum-free medium for different periods of time (2-10 days), with the addition of [3H]thymidine (5 microCi/mL) for the last 24 h. Confluent cultured chondrocytes in 25-cm2 tissue culture flasks were incubated in Ham's F-12 serum-free medium for up to 9 days with or without T3 (0.1-100 nM); the cellular cytoplasmic fraction was obtained, and alkaline phosphatase activity was evaluated using paranitrophenylphosphate as a substrate. No significant effects of T3 (0.1-100 nM) on DNA-[3H]thymidine incorporation were observed in any experiment (n = 17) for any gestational age (12-39 weeks) or for any incubation period studied (2-10 days). However, a significant (P less than 0.025 or more) stimulatory effect of T3 (0.1-100 nM) on alkaline phosphatase activity was observed after 9 days of incubation. This effect was highest for 5 nM T3 and was present in cultured chondrocytes from human fetuses of all ages studied (13-40 weeks). Cultured human fetal epiphyseal chondrocytes from human fetuses 12-40 weeks old (n = 8) showed specific nuclear binding sites for T3. The binding capacity was 27.14 +/- 2.84 fmol/100 micrograms DNA, and the Kd was 0.66 +/- 0.14 x 0.1 nM (mean +/- SEM), with no significant differences among fetal ages. In conclusion, our results show that T3 elicits a biological response in cultured human fetal epiphyseal chondrocytes and has specific nuclear binding sites. Since alkaline phosphatase is closely related to the mineralization of epiphyseal cartilage, these results suggest that thyroid hormones could regulate this process.

Alkaline Phosphatase↗
PubMed1991

High serum aluminium levels and acute reversible encephalopathy in a 4-year-old boy with acute renal failure.

We report a 4-year-old boy, in acute renal failure, who had acute encephalopathy with very high serum aluminium levels (135 micrograms/l [5 mumol/l]) after receiving vesical irrigations with alum. We believe that in situations of non-focal neurological deterioration with no apparent cause in patients with impaired renal function receiving aluminium-containing preparations, the possibility of acute aluminium poisoning should be considered.

Acute Disease↗
PubMed1990

Biological effects of androgens and identification of specific dihydrotestosterone-binding sites in cultured human fetal epiphyseal chondrocytes.

The biological effects of dihydrotestosterone (DHT) and testosterone (T) on cultured human fetal epiphyseal chondrocytes were assessed by studying the ability of these androgens to promote DNA synthesis. DNA synthesis was evaluated by measuring [3H]thymidine incorporation into DNA. After 48-h incubation in Ham's F-12 serum-free medium, chrondrocytes were incubated with or without DHT (10(-11)-10(-8) M) or T (10(-11)-10(-8) M) in MCDB-104 serum-free medium for a further 48 h, with the addition of [3H]thymidine (5 microCi/mL) for the last 24 h. In chondrocytes from five male fetuses (12-40 weeks' gestation) DHT and T significantly stimulated DNA synthesis. The maximum stimulatory effect was obtained for DHT at 10(-10) M (P less than 0.01) and for T at 10(-6) M (P less than 0.02). In chondrocytes from four female fetuses the stimulatory effect was significant only for DHT and was maximum at 10(-10) M (P less than 0.02), whereas no effect was observed for T. Cultured chondrocytes from both male and female fetuses show the presence of proteins with high affinity and limited binding capacity (Bmax) for DHT (male fetuses: Bmax, 4.9 +/- 1.9 x 10(-15) M/mg protein; Kd, 0.43 +/- 0.24 x 10(-9) M; female fetuses: Bmax, 4.8 +/- 1.6 x 10(-15) M/mg protein; Kd, 0.63 +/- 0.19 x 10(-9) M) with no significant differences between sexes. In conclusion, our results show that androgens elicit a biological response in cultured human fetal epiphyseal chondrocytes and that DHT-binding sites are present in these cells. DHT, rather than T, seems to be the active androgen. A sex difference in the degree of androgen action is also documented.

Androgen-Binding Protein↗