Methylphenidate decreases fat and carbohydrate intake in obese teenagers.

OBJECTIVE: Dopamine is a neurotransmitter that mediates the reward value of food. Methylphenidate (MPH) selectively binds and inhibits the dopamine transporter, thus increasing brain dopamine levels shortly after oral administration. This investigation studied whether a single dose of MPH decreases energy intake (EI) in obese teenagers compared to placebo (P). METHODS: This study used a single-blind, placebo-controlled, within subject design. Teenagers with body mass index (BMI) ≥95th percentile underwent two identical meal tests (P or MPH) after a 10 h fast in random order. Food was weighed before and after the meals, and EI was calculated as energy content/gram of consumed foods. Total and macronutrient EI (mean ± SD) were analyzed by Mann-Whitney U and Wilcoxon tests. RESULTS: Twenty-two subjects (15 females, 7 males) completed the study. Participants were 13.4 ± 2.2 years old and had BMI 34.9 ± 10.7 kg/m². EI from fat (167 vs. 203 kcal, P = 0.03) and carbohydrates (311 vs. 389 kcal, P = 0.04) was decreased for MPH compared to P meals, with a trend in decreased total EI (545 vs. 663 kcal, P = 0.06). CONCLUSION: A single dose of MPH decreases EI from fat and carbohydrates in obese adolescents. This effect underscores the importance of central dopamine signaling on eating behavior.

Vasoactive compounds in the neonatal period.

Sufficient organ blood flow of healthy newborn babies is maintained by relatively low systemic blood pressure. Premature infants are at an increased risk of systemic hypotension, often but not obviously, resulting in hypoperfusion of the cerebral, renal and intestinal vascular beds. Maintaining a stable blood pressure in preterm babies is of high importance in order to prevent complications such as intraventricular hemorrhage, periventricular leucomalatia, necrotizing enterocolitis or renal failure. The regulation of systemic and local hemodynamics in newborns differs substantially from that of the adults. Developmental changes in catecholamine sensitivity, higher local vasodilator factor activity and structural differences of the immature myocardium should be taken into account when applying vasoactive agents in neonates. The effects of widely used catecholamines such as dopamine, epinephrine or dobutamine can not be directly adapted from adult therapeutics to neonatal care. Their administration should be supported by data on their effects on systemic and cerebral blood flow in addition to blood pressure changes. At the bedside, neonatologists should use new diagnostic tools to differentiate between neonatal hypotension and hypoperfusion, vasoconstriction and myocardial dysfunction in order to choose the appropriate medication. Newer vasoactive agents already used in adult or pediatric cardiovascular therapy such as milrinone, levosimendan or terlipressin need to be carefully evaluated before introducing them to the treatment of neonatal hypotensive states. Well-designed preclinical and human newborn studies also evaluating their local effects are warranted.

Urinary tract infections in children: a review.

Febrile urinary tract infection is the most common serious bacterial infection in childhood, but the most appropriate evaluation of children with this condition is still unclear, overall regarding the best long-term management of children after a first UTI. Here we review current recommendations for the diagnosis, treatment, imaging evaluation and use of antibiotic prophylaxis in children with the first febrile urinary tract infection. Nevertheless, the development of a universally accepted diagnostic protocol remains elusive.

Genetic risk for recurrent urinary tract infections in humans: a systematic review.

Urinary tract infections (UTIs) are a frequent cause of morbidity in children and adults and affect up to 10% of children; its recurrence rate is estimated at 30-40%. UTI may occur in up to 50% of all women in their lifetimes and frequently require medication. Recent advances have suggested that a deregulation of candidate genes in humans may predispose patients to recurrent UTI. The identification of a genetic component of UTI recurrences will make it possible to diagnose at-risk adults and to predict genetic recurrences in their offspring. Six out of 14 genes investigated in humans may be associated with susceptibility to recurrent UTI in humans. In particular, the HSPA1B, CXCR1 & 2, TLR2, TLR4, TGF-beta1 genes seem to be associated with an alteration of the host response to UTIs at various levels.

Renal function and volume of infants born with a very low birth-weight: a preliminary cross-sectional study.

AIM: The aim of our study was to compare the function and volumes of kidneys of very low birth-weight (VLBW) and of extremely low birth-weight (ELBW) infants at pre-school ages. PATIENTS AND METHODS: We did a revision of the neonatal records of infants born in our hospital that weighed < or =1500 g at birth. The children were divided into two groups according to their weight at birth: ELBW (<1000 g) and VLBW (1000-1500 g). At the age of 5.7 +/- 1.4 years, the children underwent clinical, laboratory and ultrasound renal assessments. RESULTS: Sixty-nine children fulfilled the requirements for the study. The rate of neonatal treatment with aminoglycosides was higher in ELBW preterms. Renal function parameters, i.e. estimated glomerular filtration rate and albuminuria, did not differ between the two groups of children. Urinary alpha1-microglobulin excretion was significantly higher and kidneys were significantly smaller in the ELBW group than in the VLBW group. CONCLUSION: No impairment or differences in renal parameters were found in pre-school children born ELBW compared with those born with VLBW, except for differences in kidney volume, renal cortical thickness and urinary alpha1-microglobulin excretion. Thus, patients born with ELBW would require a longer follow-up period.

[From the newborn infant to the child, to the adult: historia magistra vitae]. / Dal neonato all'adolescente, all'uomo adulto: historia magistra vitae.

The hypothesis of the prenatal programming of adult diseases took on increasing interest from the moment that, in the 60s, an epidemiological association was proposed between low birth weight and cardiovascular diseases. In the last 20 years it has been demonstrated that individuals with low weight, low stature and thinness at birth have a higher risk of developing cardiovascular diseases and type 2 diabetes. Animal and clinical studies are casting light on the biological mechanisms underlying the association between modified development in the uterus and diseases, and on how growth in adolescence and in adult life can modulate this initial proneness to disease. One of the mechanisms that has aroused most interest among researchers is the reduced number of nephrons, associated with low birth weight, which predisposes to glomerulosclerosis and increased systemic arterial pressure in adult life. A correlation has also been found between low weight at birth and peripheral resistance to insulin. Nevertheless, it is thought that modified prenatal development is only a predisposing factor, open to profound influences in the course of postnatal development. It has in fact been demonstrated that accelerated development in the period of infancy and adolescence can extend the initial condition of neonatal suffering. Indirectly these studies renew and at the same time extend the concept of prevention, a priority aim of the physician of the third millennium.

Biochemical markers for the early assessment of neonatal sepsis: the role of procalcitonin.

Procalcitonin (PCT) is the precursor of calcitonin, normally synthesized in the C-cells of the thyroid gland. Systemic inflammation and sepsis induce PCT production by various cell types, including hepatocytes, nephrons, monocytes. PCT begins to rise four hours after exposure to bacterial endotoxins, peaking at six to eight hours, and remaining raised for at least 24 hours with a half-life of 25-30 hours. Serum PCT levels significantly increase in systemic bacterial infection, necrotizing enterocolitis, and during both early and late onset neonatal sepsis. By using a cut-off limit of 0,5 microg/L, the PCT positive likelihoud ratio was found of 12.5. PCT has a theoretical advantage as a marker of systemic induction in sepsis and its half-life suitable for daily monitoring of disease progress. PCT may be useful in assessing the severity of infection, following the progress of treatment, and predicting outcomes.

Potential risk factors for the development of acute renal failure in preterm newborn infants: a case-control study.

AIMS: To determine in a case-control study possible associations between the development of acute renal failure in preterm newborns and therapeutic interventions, particularly drug treatments. METHODS: The study population was 172 preterm infants of <38 weeks gestation; 71 had acute renal failure and 101 were controls closely matched for gestational age and birth weight. Maternal and neonatal information was collected for both groups through questionnaires and interviews. Routine data on renal variables were also collected. Univariate and multivariate logistic regression analyses were performed. RESULTS: Very low birthweight infants were at high risk of acute renal failure (79% of cases were <1500 g). However, the acute renal failure was transient. Mothers of infants with acute renal failure received more drugs during pregnancy and delivery (mainly antibiotics and non-steroidal anti-inflammatory drugs). Of the possible therapeutic interventions, intubation, catheterisation, and phototherapy were mainly applied to case subjects. A low Apgar score and patent ductus arteriosus were diagnosed in a greater percentage of neonates with acute renal failure. Moreover, in the first few days of life and before diagnosis of acute renal failure, case subjects received more drugs (antibiotics, non-steroidal anti-inflammatory drugs, and diuretics) and for a longer time. In the multivariate logistic analysis, medullary hyperechogenicity (odds ratio (OR) 4.491; 95% confidence interval (CI) 1.879 to 10.731) and ceftazidime administration (OR 5.082; 95% CI 1.493 to 17.297) were associated with a greater risk of acute renal failure. CONCLUSIONS: The results suggest the need for careful monitoring of very low birthweight infants and attention to drug treatments, as it is difficult to differentiate between normality and renal failure in the first few days of life.

Role of renal PGE2 in the adaptation from foetal to extrauterine life in term and preterm infants.

Urinary PGE(2) concentrations were assayed using a new EIA method, in 16 preterm and 18 term neonates at birth and 3 days later, since there is evidence that PGE(2) in urine are likely to reflect their renal generation and then could be correlated with kidney maturation or renal problems. PGE(2) concentrations were not different at birth (1.50+/-1.12 vs 1.56+/-1.94 ng/day), while resulted significantly higher in preterms, compared to terms, three days after birth (2.22+/-1.23 vs 1.39+/-0.79 ng/day). This increase in daily PGE(2) excretion observed only in preterm neonates could be due to an increased renal biosynthesis as a mechanism of compensatory response to prevent further decrements in renal plasma flow, since prostanoids play an important role in protecting the immature kidney from high levels of angiotensin II. Otherwise, the passive reabsorption of PGE(2) along the distal nephron could be altered because of kidney immaturity. The measurement of PGE(2) in urine of neonates, particularly prematures, could be useful to provide a better understanding of the homeostatic function of the kidney in the phase of adaptation to extra-uterine life.

[Solitary kidney]. / Il rene solitario.

A functionally solitary kidney may be the consequence of renal agenesis, dysplasia, or surgical procedures. Compensatory hypertrophy and physiologic mechanisms intervene to preserve renal function. The authors discuss the physiopathology of solitary kidney in several clinical conditions.