The role of lean body mass and physical activity in bone health in children

In the context of physical education curricula, markers of physical fitness (e.g., aerobic capacity, muscular strength, flexibility, and body mass index or body fat) are usually evaluated in reference to health standards. Despite their possible mediating role in the relationship between weight-bearing or muscle forces and features of bone tissue, these attributes of fitness may not be the most relevant to predict skeletal health. It is therefore important to analyze the relative contribution of these factors to the variability in bone tissue of different parts of the skeleton, and to analyze it by gender, as sensitivity to mechanical loading can diverge for boys and girls. We compared the effects of habitual physical activity (PA) and lean mass, as surrogates of weight-bearing and muscle forces, and of physical fitness (aerobic and muscle capacity of lower and upper limbs) on bone mineral content (BMC) and size of total body, lumbar spine, femoral neck, and 1/3 radius in 53 girls and 64 boys from 7.9 to 9.7 years of age. After controlling for bone age, body mass, body height, and calcium intake, lean mass was the most important predictor of bone size and/or mineral in both genders (p < 0.05), while habitual weight-bearing PA positively influenced BMC in boys (p < 0.05). The effect of muscle in bone was not determined by PA and fitness score did not explain bone variability. Femoral neck was the bone site more closely associated with mechanical loading factors; boys with a PA > 608 counts/min/day (~105 min/day of moderate and vigorous intensity) showed 13–20% more BMC than those with less physical activity, and girls with a lean mass >19 kg showed 12–19% more BMC than those with less lean mass. These findings suggest that lean mass was the most important predictor of bone size and/or mineralization in both genders, while habitual weight-bearing PA appears to positively impact on bone mineral in prepubertal boys and that both lean mass and PA need to be considered in physical education curricula and other health-enhancing programs.     

Intrinsic expression of Nod2 in CD4+ T lymphocytes is not necessary for the development of cell-mediated immunity and host resistance to Toxoplasma gondii

Nod2 belongs to the nucleotide-binding domain leucine-rich repeat family of proteins and senses bacterial cell wall components to initiate innate immune responses against various pathogens. Recently, it has been reported that T-cell-intrinsic expression of Nod2 promotes host defense against Toxoplasma gondii infection by inducing type 1 immunity. Here, we present results that demonstrate that Nod2 does not play a role in the defense against T. gondii infection. Nod2-deficient mice were fully capable of inducing Th1 immune responses and did not show enhanced susceptibility to infection. Upon TCR stimulation in vitro, Nod2-deficient CD4(+) T cells showed normal activation, IL-2 production, proliferation, and Th1/2 differentiation. Nod2 mRNA and protein were expressed in CD4(+) T and CD8(+) T cells at substantial levels. Therefore, Nod2, although expressed in CD4(+) T cells, does not have an intrinsic function in T-cell activation and differentiation.     

BEL-2, an Extended-Spectrum β-Lactamase with Increased Activity toward Expanded-Spectrum Cephalosporins in Pseudomonas aeruginosa

A Pseudomonas aeruginosa isolate recovered in Belgium produced a novel extended-spectrum ß-lactamase, BEL-2, differing from BEL-1 by a single Leu162Phe substitution. That modification significantly altered the kinetic properties of the enzyme, increasing its affinity for expanded-spectrum cephalosporins. The bla_BEL-2 gene was identified from a P. aeruginosa isolate clonally related to another bla_BEL-1-positive isolate.Extended-spectrum ß-lactamases (ESBLs), such as TEM, SHV, PER, VEB, GES, and more recently, CTX-M variants, are reported increasingly to be found in Pseudomonas aeruginosa in various areas (1, 2, 7, 8, 10-12, 15, 17, 21, 23, 27, 28, 30). The BEL-1 ß-lactamase, distantly related to other ESBLs, was identified from a P. aeruginosa isolate from Roeselare, Belgium, which interestingly shows resistance to ticarcillin and ceftazidime but only reduced susceptibility to piperacillin, cefepime, cefpirome, and aztreonam (24). The bla_BEL-1 determinant was found as a gene cassette in the chromosome-borne class 1 integron, In120, that includes other resistance genes (aacA4, aadA5, and smr2) and that was part of a Tn1404-type transposon structure (24). Very recently, Bogaerts et al. (5) reported on the diffusion of BEL-1-producing isolates in various hospital centers of Belgium and also found that BEL-1 could be associated with other relevant β-lactamases, such as the VIM-1 metallo-β-lactamase (5).P. aeruginosa isolate 531 (this study) was recovered from a urine sample of a patient hospitalized in Roeselare, Belgium, in February 2007 for pneumonia and was resistant to all β-lactams but imipenem (Table ​(Table1).1). A synergy between aztreonam or ceftazidime and clavulanic acid-containing disks suggested the synthesis of an ESBL (19). PCR followed by sequencing using ESBL gene-specific primers (24) identified a novel gene encoding BEL-2, which differs from BEL-1 by a single amino acid substitution (Leu to Phe at Ambler position 162) (3). Transfer of a ß-lactam resistance marker from P. aeruginosa 531 to Escherichia coli or to P. aeruginosa reference strains was unsuccessful by either conjugation or transformation (25). Plasmid extraction performed as described previously (14) did not identify any plasmid, suggesting a chromosomal location of the bla_BEL-2-like gene in P. aeruginosa 531. A pulsed-field gel electrophoresis (PFGE) analysis (4) showed that isolates 531 (BEL-2 positive) and 51170 (BEL-1 positive), recovered from the same geographical area, were clonally related. A PCR mapping approach confirmed the presence of a class 1 integron whose structure was identical to that of In120 of P. aeruginosa 51170 (24) and identified an identical structure in P. aeruginosa 531 (data not shown). Overall, these data suggest that the bla_BEL-2 sequence likely resulted from a mutational event that had occurred in In120-carrying P. aeruginosa strains.

TABLE 1.

MICs of β-lactams^a

Extraosseous vulvar chondroma: a case report

BACKGROUND: Extraosseous chondromas are cartilaginous tissue tumors with a nodular appearance on the hands and feet. There are reports of these tumors occurring on the knee, neck, back, liver and testis and in the oral cavity. Occurrence in the pelvis is generally rare. The origin is metaplastic and may be mesenchymal or subcelomic. Treatment is by surgery and requires removing the tumor with a safety margin. Recurrences are infrequent, and distant metastasis has never been reported. CASE: An 11-year-old girl was referred for a painless solid tumor located on the mons pubis. Surgical removal of the tumor with a safety margin was performed. Macroscopically, the tumor was shiny when cut open and yellowish. Microscopic examination revealed a very distinct cartilage-forming tumor compatible with extraosseous chondroma. Two years after the operation, the patient had no recurrence. CONCLUSION: Extraosseous chondroma is a rare benign tumor. Finding it in children is even less frequent, and localization in the vulvar region has never before been reported. This appears to be the first such report of this type of tumor in this region and age range.     

Lipid profile in women over 35 years old using triphasic combined oral contraceptives

Twenty-nine women aged 35 years old or more, using triphasic combined oral contraceptive (COC) were evaluated during six cycles for the following parameters: total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and its subfraction HDL2, triglycerides, apoproteins A and B, Castelli risk index I and II (cholesterol/HDL-C and LDL-C/HDL-C) and apoprotein ratio (apoprotein B/apoprotein A). The same laboratory measurements were done in a control group of 49 non-COC-user women. The results showed that there were no differences on most of the studied parameters between user and nonuser women. There was a significant reduction of HDL-C and HDL2-C, although within the normal range. In addition, it was observed a significant increment of triglycerides and apoprotein B at 6 months of follow-up only in user group (p < 0.05), although within the normal range. It is concluded that the use of levonorgestrel triphasic COC appeared to have no additional adverse impact when used by women aged over 35 years. Further studies are needed to obtain conclusive data.     

Chemical afferent vagal axotomy blocks re-intake after partial withdrawal of gastric food contents

Objectives: The aim of this study was to investigate the biological process by which animals regulate meal size. An experimental procedure for its study is to examine food re-intake after partial withdrawal of gastric food contents.

Methods: The aim of the present experiments was to investigate the role of vagal afferents in food re-intake after perivagal administration of capsaicin, a neurotoxin that specifically damages weakly myelinated or unmyelinated vagal sensory axons.

Results: In experiment 1, capsaicin-treated animals initially consumed higher amounts of food in comparison to controls (in first 24 hours) but their excess intake was compensated for in subsequent daily satiation tests. However, capsaicin treatment impaired the common short-term re-intake behavior observed in control rats after partial removal of gastric food nutrients, and the lesioned animals consumed significantly less food than had been withdrawn after completion of the initial meal; moreover, in this deficit condition, no counteraction was observed in subsequent repeated tests. This behavioral disturbance cannot be attributed to an indirect effect of capsaicin on gastric emptying volume, because the stomach contents were similar in both groups (Experiment 2).

Discussion: These findings are discussed in terms of the critical role played by vagal afferents in rapid visceral adjustments related to short-term food intake, as also observed in other gastrointestinal regulatory behaviors that require immediate processing of visceral sensory information.     

25(OH)D Levels in Relation to Gender,Overweight, Insulin Resistance,and Inflammation in a Cross-Sectional Cohort of Northern Italian Workers: Evidence in Support of Preventive Health Care Programs

Objective: In recent years, the welfare of workers and the prevention of chronic disabling diseases has become a topic of great interest. This study investigates serum levels of total 25-hydroxyvitamin D (25(OH)D) in a cohort of overweight–obese and insulin-resistant northern Italian indoor workers in apparent good health followed a nutritional education program.

Methods: An observational cross-sectional study on 385 patients (females = 291, males = 94), age range 18–69 years and body mass index (BMI) > 25 kg/m², was performed at the Department of Occupational Medicine Milan, Italy, latitude 45.465454 N. We evaluated nutritional intakes, occupational and leisure physical activity, anthropometric measurements, impedance evaluation, blood pressure, the presence of metabolic syndrome (MetS) and nonalcoholic fatty liver diseases (NAFLD) by fatty liver index (FLI). Hematologic and biochemical parameters and (25(OH)D) levels were evaluated from fasting blood samples.

Results: Only 10.91% of subjects had optimal values of 25(OH)D; 17.40% of the remaining 89.09% subjects were severely deficient, with no gender difference and insufficient intake of vitamin D. Only 28% declared leisure physical activity; 39.48% had metabolic syndrome and 62.60% had an FLI > 30. An inverse relationship between 25(OH)D levels and BMI was found, with a significant reduction of total 25(OH)D serum concentrations in winter. The homeostasis model assessment–insulin resistance (HOMA-IR) is positively related to BMI and inversely related to 25(OH)D concentrations. A positive correlation between vitamin D and leisure physical activity was found. At univariate analysis adjusted for age, gender and BMI, an inverse relationship between vitamin D and FLI was observed in both genders. The correlation between 25(OH)D levels, inflammation markers, BMI, and FLI showed an increased risk of cardiovascular disease in this cohort of workers.

Conclusion: Our results suggest the rationale for a large-scale screening program for vitamin D by means of easily implementable low-cost preventive supplementation.