Histone proteoform analysis reveals epigenetic changes in adult mouse brown adipose tissue in response to cold stress

BACKGROUND

Regulation of the thermogenic response by brown adipose tissue (BAT) is an important component of energy homeostasis with implications for the treatment of obesity and diabetes. Our preliminary analyses of RNA-Seq data uncovered many nodes representing epigenetic modifiers that are altered in BAT in response to chronic thermogenic activation. Thus, we hypothesized that chronic thermogenic activation broadly alters epigenetic modifications of DNA and histones in BAT.

RESULTS

Motivated to understand how BAT function is regulated epigenetically, we developed a novel method for the first-ever unbiased top-down proteomic quantitation of histone modifications in BAT and validated our results with a multi-omic approach. To test our hypothesis, wildtype male C57BL/6J mice were housed under chronic conditions of thermoneutral temperature (TN, 28°C), mild cold/room temperature (RT, 22°C), or severe cold (SC, 8°C) and BAT was analyzed for DNA methylation and histone modifications. Methylation of promoters and intragenic regions in genomic DNA decrease in response to chronic cold exposure. Integration of DNA methylation and RNA expression datasets suggest a role for epigenetic modification of DNA in regulation of gene expression in response to cold. In response to cold housing, we observe increased bulk acetylation of histones H3.2 and H4, increased histone H3.2 proteoforms with di- and trimethylation of lysine 9 (K9me2 and K9me3), and increased histone H4 proteoforms with acetylation of lysine 16 (K16ac) in BAT.

CONCLUSIONS

Our results reveal global epigenetically-regulated transcriptional "on" and "off" signals in murine BAT in response to varying degrees of chronic cold stimuli and establish a novel methodology to quantitatively study histones in BAT, allowing for direct comparisons to decipher mechanistic changes during the thermogenic response. Additionally, we make histone PTM and proteoform quantitation, RNA splicing, RRBS, and transcriptional footprint datasets available as a resource for future research.

Histone proteoform analysis reveals epigenetic changes in adult mouse brown adipose tissue in response to cold stress

Regulation of the thermogenic response by brown adipose tissue (BAT) is an important component of energy homeostasis with implications for the treatment of obesity and diabetes. Our preliminary analyses uncovered many nodes representing epigenetic modifiers that are altered in BAT in response to chronic thermogenic activation. Thus, we hypothesized that chronic thermogenic activation broadly alters epigenetic modifications of DNA and histones in BAT. Motivated to understand how BAT function is regulated epigenetically, we developed a novel method for the first-ever unbiased top-down proteomic quantitation of histone modifications in BAT and validated our results with a multi-omic approach. To test our hypothesis, wildtype male C57BL/6J mice were housed under chronic conditions of thermoneutral temperature (TN, 28.8°C), mild cold/room temperature (RT, 22°C), or severe cold (SC, 8°C) and BAT was analyzed for DNA methylation and histone modifications. Methylation of promoters and intragenic regions in genomic DNA decrease in response to chronic cold exposure. Integration of DNA methylation and RNA expression data suggest a role for epigenetic modification of DNA in gene regulation in response to cold. In response to cold housing, we observe increased bulk acetylation of histones H3.2 and H4, increased histone H3.2 proteoforms with di- and trimethylation of lysine 9 (K9me2 and K9me3), and increased histone H4 proteoforms with acetylation of lysine 16 (K16ac) in BAT. Taken together, our results reveal global epigenetically-regulated transcriptional "on" and "off" signals in murine BAT in response to varying degrees of chronic cold stimuli and establish a novel methodology to quantitatively study histones in BAT, allowing for direct comparisons to decipher mechanistic changes during the thermogenic response. Additionally, we make histone PTM and proteoform quantitation, RNA splicing, RRBS, and transcriptional footprint datasets available as a resource for future research.

Genetic variants in ALDH1L1 and GLDC influence the serine-to-glycine ratio in Hispanic children

BACKGROUND

Glycine is a proteogenic amino acid that is required for numerous metabolic pathways, including purine, creatine, heme, and glutathione biosynthesis. Glycine formation from serine, catalyzed by serine hydroxy methyltransferase, is the major source of this amino acid in humans. Our previous studies in a mouse model have shown a crucial role for the 10-formyltetrahydrofolate dehydrogenase enzyme in serine-to-glycine conversion.

OBJECTIVES

We sought to determine the genomic influence on the serine-glycine ratio in 803 Hispanic children from 319 families of the Viva La Familia cohort.

METHODS

We performed a genome-wide association analysis for plasma serine, glycine, and the serine-glycine ratio in Sequential Oligogenic Linkage Analysis Routines while accounting for relationships among family members.

RESULTS

All 3 parameters were significantly heritable (h2 = 0.22-0.78; P < 0.004). The strongest associations for the serine-glycine ratio were with single nucleotide polymorphisms (SNPs) in aldehyde dehydrogenase 1 family member L1 (ALDH1L1) and glycine decarboxylase (GLDC) and for glycine with GLDC (P < 3.5 × 10-8; effect sizes, 0.03-0.07). No significant associations were found for serine. We also conducted a targeted genetic analysis with ALDH1L1 exonic SNPs and found significant associations between the serine-glycine ratio and rs2886059 (β = 0.68; SE, 0.25; P = 0.006) and rs3796191 (β = 0.25; SE, 0.08; P = 0.003) and between glycine and rs3796191 (β = -0.08; SE, 0.02; P = 0.0004). These exonic SNPs were further associated with metabolic disease risk factors, mainly adiposity measures (P < 0.006). Significant genetic and phenotypic correlations were found for glycine and the serine-glycine ratio with metabolic disease risk factors, including adiposity, insulin sensitivity, and inflammation-related phenotypes [estimate of genetic correlation = -0.37 to 0.35 (P < 0.03); estimate of phenotypic correlation = -0.19 to 0.13 (P < 0.006)]. The significant genetic correlations indicate shared genetic effects among glycine, the serine-glycine ratio, and adiposity and insulin sensitivity phenotypes.

CONCLUSIONS

Our study suggests that ALDH1L1 and GLDC SNPs influence the serine-to-glycine ratio and metabolic disease risk.

COPB2 loss of function causes a coatopathy with osteoporosis and developmental delay

Coatomer complexes function in the sorting and trafficking of proteins between subcellular organelles. Pathogenic variants in coatomer subunits or associated factors have been reported in multi-systemic disorders, i.e., coatopathies, that can affect the skeletal and central nervous systems. We have identified loss-of-function variants in COPB2, a component of the coatomer complex I (COPI), in individuals presenting with osteoporosis, fractures, and developmental delay of variable severity. Electron microscopy of COPB2-deficient subjects' fibroblasts showed dilated endoplasmic reticulum (ER) with granular material, prominent rough ER, and vacuoles, consistent with an intracellular trafficking defect. We studied the effect of COPB2 deficiency on collagen trafficking because of the critical role of collagen secretion in bone biology. COPB2 siRNA-treated fibroblasts showed delayed collagen secretion with retention of type I collagen in the ER and Golgi and altered distribution of Golgi markers. copb2-null zebrafish embryos showed retention of type II collagen, disorganization of the ER and Golgi, and early larval lethality. Copb2+/- mice exhibited low bone mass, and consistent with the findings in human cells and zebrafish, studies in Copb2+/- mouse fibroblasts suggest ER stress and a Golgi defect. Interestingly, ascorbic acid treatment partially rescued the zebrafish developmental phenotype and the cellular phenotype in Copb2+/- mouse fibroblasts. This work identifies a form of coatopathy due to COPB2 haploinsufficiency, explores a potential therapeutic approach for this disorder, and highlights the role of the COPI complex as a regulator of skeletal homeostasis.

Genetic variants and physical activity interact to affect bone density in Hispanic children

Background

Our aim was to investigate if moderate to vigorous physical activity (MVPA), calcium intake interacts with bone mineral density (BMD)-related single nucleotide polymorphisms (SNPs) to influence BMD in 750 Hispanic children (4-19y) of the cross-sectional Viva La Familia Study.

Methods

Physical activity and dietary intake were measured by accelerometers and multiple-pass 24 h dietary recalls, respectively. Total body and lumbar spine BMD were measured by dual energy X-ray absorptiometry. A polygenic risk score (PRS) was computed based on SNPs identified in published literature. Regression analysis was conducted with PRSs, MVPA and calcium intake with total body and lumbar spine BMD.

Results

We found evidence of statistically significant interaction effects between the PRS and MVPA on total body BMD and lumbar spine BMD (p < 0.05). Higher PRS was associated with a lower total body BMD (β = − 0.040 ± 0.009, p = 1.1 × 10^− 5) and lumbar spine BMD (β = − 0.042 ± 0.013, p = 0.0016) in low MVPA group, as compared to high MVPA group (β = − 0.015 ± 0.006, p = 0.02; β = 0.008 ± 0.01, p = 0.4, respectively).

Discussion

The study indicated that calcium intake does not modify the relationship between genetic variants and BMD, while it implied physical activity interacts with genetic variants to affect BMD in Hispanic children. Due to limited sample size of our study, future research on gene by environment interaction on bone health and functional studies to provide biological insights are needed.

Conclusions

Bone health in Hispanic children with high genetic risk for low BMD is benefitted more by MVPA than children with low genetic risk. Our results may be useful to predict disease risk and tailor dietary and physical activity advice delivery to people, especially children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02537-y.

Serum Urate, PUFAs and Abdominal Obesity in Hispanic Children: The Viva La Familia Study

Objectives

Elevated serum urate is known to increase chronic kidney and cardiovascular disease risk. Studies in adults have shown inverse association between serum urate and n-3 polyunsaturated fatty acids (PUFAs), particularly eicosapentaenoic acid (EPA). Here, we aimed to determine the relationship between serum levels of PUFAs and urate in overweight/obese Hispanic children of the Viva La Familia Study (VFS) and then test whether it is mediated by obesity and insulin resistance.

Methods

VFS was designed to determine the genetic and environmental effects on childhood obesity. n-3 (EPA, alpha-linolenic acid (ALA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA)) and n-6 (arachidonic acid (AA), linoleic acid (LA), eicosadienoic and docosadienoic acid) PUFAs were measured as part of metabolomic profiling (N = 782). Quantitative genetic and phenotypic analyses were conducted using SOLAR. Mediation analysis was conducted using Baron and Kenny approach with waist circumference (WC), BMIZ and HOMA (measures of obesity and insulin resistance) as mediators.

Results

Phenotypic correlations showed that serum urate was positively associated with LA (β = 0.08 (0.02), P &lt; 0.0001), ALA (β = 0.03 (0.01), P &lt; 0.05), eicosadienoic (β = 0.09 (0.02), P &lt; 0.0001) and docosadienoic acid (β = 0.04 (0.007), P &lt; 0.0001). Further analysis showed inverse genetic correlations between serum urate and EPA (rhog = −0.30 (0.14), P &lt; 0.05), BMIZ (rhog = 0.45 (0.12), P &lt; 0.005) and waist circumference (rhog = 0.42 (0.11), P &lt; 0.005). The genetic correlation between serum urate and EPA remained significant after adjustment for BMIZ (rhog = −0.27 (0.13), P &lt; 0.05) and HOMA (rhog = −0.23 (0.13), P &lt; 0.05). However, it was no longer significant after adjustment for WC (rhog = −0.21 (0.13), P = 0.10). No statistical significance was observed for other PUFAs.

Conclusions

Our genetic analysis suggests pleiotropic relationship between EPA and serum urate levels as observed in adults. This relationship seems to be mediated by WC, a surrogate measure for abdominal obesity, but not by BMIZ or HOMA. Further investigations are warranted to determine the role of EPA in reducing serum urate and its implications for associated diseases.

Funding Sources

NIDDK.

Genetic variants affecting bone mineral density and bone mineral content at multiple skeletal sites in Hispanic children

CONTEXT

Osteoporosis is a major public health burden with significant economic costs. However, the correlates of bone health in Hispanic children are understudied.

OBJECTIVE

We aimed to identify genetic variants associated with bone mineral density (BMD) and bone mineral content (BMC) at multiple skeletal sites in Hispanic children.

METHODS

We conducted a cross-sectional genome-wide linkage analysis, genome-wide and exome-wide association analysis of BMD and BMC. The Viva La Familia Study is a family-based cohort with a total of 1030 Hispanic children (4-19 years old at baseline) conducted in Houston, TX. BMD and BMC were measured by Dual-energy X-ray absorptiometry.

RESULTS

Significant heritability were observed for BMC and BMD at multiple skeletal sites ranging between 44 and 68% (P < 2.8 × 10-9). Significant evidence for linkage was found for BMD of pelvis and left leg on chromosome 7p14, lumbar spine on 20q13 and left rib on 6p21, and BMC of pelvis on chromosome 20q12 and total body on 14q22-23 (logarithm of odds score > 3). We found genome-wide significant association between BMC of right arm and rs762920 at PVALB (P = 4.6 × 10-8), and between pelvis BMD and rs7000615 at PTK2B (P = 7.4 × 10-8). Exome-wide association analysis revealed novel association of variants at MEGF10 and ABRAXAS2 with left arm and lumber spine BMC, respectively (P < 9 × 10-7).

CONCLUSIONS

We identified novel loci associated with BMC and BMD in Hispanic children, with strongest evidence for PTK2B. These findings provide better understanding of bone genetics and shed light on biological mechanisms underlying BMD and BMC variation.

Genetic variation underlying renal uric acid excretion in Hispanic children: the Viva La Familia Study

Background

Reduced renal excretion of uric acid plays a significant role in the development of hyperuricemia and gout in adults. Hyperuricemia has been associated with chronic kidney disease and cardiovascular disease in children and adults. There are limited genome-wide association studies associating genetic polymorphisms with renal urate excretion measures. Therefore, we investigated the genetic factors that influence the excretion of uric acid and related indices in 768 Hispanic children of the Viva La Familia Study.

Methods

We performed a genome-wide association analysis for 24-h urinary excretion measures such as urinary uric acid/urinary creatinine ratio, uric acid clearance, fractional excretion of uric acid, and glomerular load of uric acid in SOLAR, while accounting for non-independence among family members.

Results

All renal urate excretion measures were significantly heritable (p <2 × 10⁻⁶) and ranged from 0.41 to 0.74. Empirical threshold for genome-wide significance was set at p <1 × 10⁻⁷. We observed a strong association (p < 8 × 10⁻⁸) of uric acid clearance with a single nucleotide polymorphism (SNP) in zinc finger protein 446 (ZNF446) (rs2033711 (A/G), MAF: 0.30). The minor allele (G) was associated with increased uric acid clearance. Also, we found suggestive associations of uric acid clearance with SNPs in ZNF324, ZNF584, and ZNF132 (in a 72 kb region of 19q13; p <1 × 10⁻⁶, MAFs: 0.28–0.31).

Conclusion

For the first time, we showed the importance of 19q13 region in the regulation of renal urate excretion in Hispanic children. Our findings indicate differences in inherent genetic architecture and shared environmental risk factors between our cohort and other pediatric and adult populations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-016-0366-3) contains supplementary material, which is available to authorized users.

Serum uric acid concentrations and SLC2A9 genetic variation in Hispanic children: the Viva La Familia Study

BACKGROUND

Elevated concentrations of serum uric acid are associated with increased risk of gout and renal and cardiovascular diseases. Genetic studies in adults have consistently identified associations of solute carrier family 2, member 9 (SLC2A9), polymorphisms with variation in serum uric acid. However, it is not known whether the association of serum uric acid with SLC2A9 polymorphisms manifests in children.

OBJECTIVE

The aim was to investigate whether variation in serum uric acid is under genetic influence and whether the association with SLC2A9 polymorphisms generalizes to Hispanic children of the Viva La Familia Study.

DESIGN

We conducted a genomewide association study with 1.1 million genetic markers in 815 children.

RESULTS

We found serum uric acid to be significantly heritable [h(2) ± SD = 0.45 ± 0.08, P = 5.8 × 10(-11)] and associated with SLC2A9 variants (P values between 10(-16) and 10(-7)). Several of the significantly associated polymorphisms were previously identified in studies in adults. We also found positive genetic correlations between serum uric acid and BMI z score (ρG = 0.45, P = 0.002), percentage of body fat (ρG = 0.28, P = 0.04), fat mass (ρG = 0.34, P = 0.02), waist circumference (ρG = 0.42, P = 0.003), and waist-to-height ratio (ρG = 0.46, P = 0.001).

CONCLUSIONS

Our results show that variation in serum uric acid in Hispanic children is under considerable genetic influence and is associated with obesity-related phenotypes. As in adults, genetic variation in SLC2A9 is associated with serum uric acid concentrations, an important biomarker of renal and cardiovascular disease risk, in Hispanic children.

Energetic adaptations persist after bariatric surgery in severely obese adolescents

OBJECTIVE

Energetic adaptations induced by bariatric surgery have not been studied in adolescents or for extended periods postsurgery. Energetic, metabolic, and neuroendocrine responses to Roux-en-Y gastric bypass (RYGB) surgery were investigated in extremely obese adolescents.

METHODS

At baseline and at 1.5, 6, and 12 months post-baseline, 24-h room calorimetry, body composition, and fasting blood biochemistries were measured in 11 obese adolescents relative to five matched controls.

RESULTS

In the RYGB group, mean weight loss was 44 ± 19 kg at 12 months. Total energy expenditure (TEE), activity EE, basal metabolic rate (BMR), sleep EE, and walking EE significantly declined by 1.5 months (P = 0.001) and remained suppressed at 6 and 12 months. Adjusted for age, sex, fat-free mass, and fat mass, EE was still lower than baseline (P = 0.001). Decreases in serum insulin, leptin, and triiodothyronine (T3), gut hormones, and urinary norepinephrine (NE) paralleled the decline in EE. Adjusted changes in TEE, BMR, and/or sleep EE were associated with decreases in insulin, homeostatic model assessment, leptin, thyroid stimulating hormone, total T3, peptide YY3-36, glucagon-like peptide-2, and urinary NE and epinephrine (P = 0.001-0.05).

CONCLUSIONS

Energetic adaptations in response to RYGB-induced weight loss are associated with changes in insulin, adipokines, thyroid hormones, gut hormones, and sympathetic nervous system activity and persists 12 months postsurgery.

Genome-wide association replicates the association of Duffy antigen receptor for chemokines (DARC) polymorphisms with serum monocyte chemoattractant protein-1 (MCP-1) levels in Hispanic children

Obesity is associated with a chronic low inflammatory state characterized by elevated levels of chemokines. Monocyte chemoattractant protein-1 (MCP-1) is a member of the cysteine-cysteine (CC) chemokine family and is increased in obesity. The purpose of this study was to identify loci regulating serum MCP-1 in obese Hispanic children from the Viva La Familia Study. A genome-wide association (GWA) analysis was performed in 815 children, ages 4-19 years, using genotypes assayed with the Illumina HumanOmni1-Quad v1.0 BeadChips. All analyses were performed in SOLAR using a linear regression-based test under an additive model of allelic effect, while accounting for the relatedness of family members via a kinship variance component. The strongest association for MCP-1 levels was found with a non-synonymous single nucleotide polymorphism (SNP), rs12075, resulting in an amino acid substitution (Asp42Gly) in the Duffy antigen receptor for chemokines (DARC) gene product (minor allele frequency=43.6%, p=1.3 × 10(-21)) on chromosome 1. Four other DARC SNPs were also significantly associated with MCP-1 levels (p<10(-16)-10(-6)). The Asp42Gly variant was associated with higher levels of MCP-1 and accounted for approximately 10% of its variability. In addition, MCP-1 levels were significantly associated with SNPs in chemokine receptor 3 (CCR3) and caspase recruitment domain family, member 9 (CARD9). In summary, the association of the DARC Asp42Gly variant with MCP-1 levels replicates previous GWA results substantiating a potential role for DARC in the regulation of pro-inflammatory cytokines.

A genetic contribution to circulating cytokines and obesity in children

Cytokines are considered to be involved in obesity-related metabolic diseases. Study objectives are to determine the heritability of circulating cytokine levels, to investigate pleiotropy between cytokines and obesity traits, and to present genome scan results for cytokines in 1030 Hispanic children enrolled in VIVA LA FAMILIA Study. Cytokine phenotypes included monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-alpha), leptin, adiponectin, soluble intercellular adhesion molecule-1 (sICAM-1), transforming growth factor beta 1 (TGF-beta1), C-reactive protein (CRP), regulated upon activation, normal T-cell expressed and secreted (RANTES) and eotaxin. Obesity-related phenotypes included body mass index (BMI), fat mass (FM), truncal FM and fasting serum insulin. Heritabilities ranged from 0.33 to 0.97. Pleiotropy was observed between cytokines and obesity traits. Positive genetic correlations were seen between CRP, leptin, MCP-1 and obesity traits, and negative genetic correlations with adiponectin, ICAM-1 and TGF-beta1. Genome-wide scan of sICAM-1 mapped to chromosome 3 (LOD=3.74) between markers D3S1580 and D3S1601, which flanks the adiponectin gene (ADIPOQ). Suggestive linkage signals were found in other chromosomal regions for other cytokines. In summary, significant heritabilities for circulating cytokines, pleiotropy between cytokines and obesity traits, and linkage for sICAM-1 on chromosome 3q substantiate a genetic contribution to circulating cytokine levels in Hispanic children.

Body size, body composition, and metabolic profile explain higher energy expenditure in overweight children

Lower relative rates of energy expenditure (EE), increased energetic efficiency, and altered fuel utilization purportedly associated with obesity have not been demonstrated indisputably in overweight children. We hypothesized that differences in energy metabolism between nonoverweight and overweight children are attributable to differences in body size and composition, circulating thyroid hormones, sympathetic nervous system, and adrenomedullary activity. A total of 836 Hispanic children, 5-19 y old, participated in 24-h calorimetry, anthropometric, and dual-energy X-ray absorptiometry measurements. Biochemistries were determined by standard techniques. Absolute total EE (TEE) and its components (sleep EE, basal EE, sedentary EE, cycling EE, walking EE, activity EE, nonexercising activity thermogenesis) were higher in overweight children (P = 0.001). Net mechanical energetic efficiency of cycling was lower in overweight children (P = 0.001). Adjusting for body size and composition accounted for differences in TEE, its components, and energetic efficiency. Net carbohydrate and fat utilization did not differ between groups. TEE was independently influenced by sex, Tanner stage, fat free mass, fat mass (FM), fasting serum nonesterified fatty acids (NEFA), leptin, free thyroxine, triiodothyronine, and 24-h urinary norepinephrine and epinephrine. Fat utilization was independently associated with age2, sex, FM, fasting serum NEFA, triacylglycerol, adiponectin, leptin, total thyroxine, and free triiodothyronine. Higher EE in overweight children was largely explained by differences in body size and composition, with minor contributions of thyroid and sympathoadrenal systems. Alterations in EE, energetic efficiency, and substrate utilization were not evident in the overweight children.

Genome-wide scan for serum ghrelin detects linkage on chromosome 1p36 in Hispanic children: results from the Viva La Familia study

This study was conducted to investigate genetic influence on serum ghrelin and its relationship with adiposity-related phenotypes in Hispanic children (n=1030) from the Viva La Familia study (VFS). Anthropometric measurements and levels of serum ghrelin were estimated and genetic analyses conducted according to standard procedures. Mean age, body mass index (BMI), and serum ghrelin were 11+/-0.13 y, 25+/-0.24 kg/m2 and 38+/-0.5 ng/mL, respectively. Significant heritabilities (p<0.001) were obtained for BMI, weight, fat mass, percent fat, waist circumference, waist-to-height ratio, and ghrelin. Bivariate analyses of ghrelin with adiposity traits showed significant negative genetic correlations (p<0.0001) with weight, BMI, fat mass, percent fat, waist circumference, and waist-to-height ratio. A genome-wide scan for ghrelin detected significant linkage on chromosome 1p36.2 between STR markers D1S2697 and D1S199 (LOD=3.2). The same region on chromosome 1 was the site of linkage for insulin (LOD=3.3), insulinlike growth factor binding protein 1 (IGFBP1) (LOD=3.4), homeostatic model assessment method (HOMA) (LOD=2.9), and C-peptide (LOD=2.0). Several family-based studies have reported linkages for obesity-related phenotypes in the region of 1p36. These results indicate the importance of this region in relation to adiposity in children from the VFS.

Quantitative genetic analysis of the metabolic syndrome in Hispanic children

Childhood obesity is associated with a constellation of metabolic derangements including glucose intolerance, hypertension, and dyslipidemia, referred to as metabolic syndrome. The purpose of this study was to investigate genetic and environmental factors contributing to the metabolic syndrome in Hispanic children. Metabolic syndrome, defined as having three or more metabolic risk components, was determined in 1030 Hispanic children, ages 4-19 y, from 319 families enrolled in the VIVA LA FAMILIA study. Anthropometry, body composition by dual energy x-ray absorptiometry, clinical signs, and serum biochemistries were measured using standard techniques. Risk factor analysis and quantitative genetic analysis were performed. Of the overweight children, 20%, or 28% if abnormal liver function is included in the definition, presented with the metabolic syndrome. Odds ratios for the metabolic syndrome were significantly increased by body mass index z-score and fasting serum insulin; independent effects of sex, age, puberty, and body composition were not seen. Heritabilities +/- SE for waist circumference, triglycerides (TG), HDL, systolic blood pressure (SBP), glucose, and alanine aminotransferase (ALT) were highly significant. Pleiotropy (a common set of genes affecting two traits) detected between SBP and waist circumference, SBP and glucose, HDL and waist circumference, ALT and waist circumference, and TG and ALT may underlie the clustering of the components of the metabolic syndrome. Significant heritabilities and pleiotropy seen for the components of the metabolic syndrome indicate a strong genetic contribution to the metabolic syndrome in overweight Hispanic children.

Genetic and environmental factors influencing fasting serum adiponectin in Hispanic children

CONTEXT

Because of its antiinflammatory and insulin-sensitizing properties, adiponectin may play a role in the development of cardiovascular disease and type 2 diabetes.

OBJECTIVES

The aims of these analyses were: 1) to estimate the heritability of fasting serum adiponectin; 2) to evaluate the effects of age, sex, and body composition on fasting serum adiponectin; 3) to test for associations between fasting serum adiponectin and diet, fitness, energy expenditure, and fat oxidation; and 4) to determine the relationships between fasting serum adiponectin, insulin and lipids, and blood pressure in Hispanic children.

DESIGN

Genetic and environmental factors influencing fasting serum adiponectin were investigated in a cohort of children participating in the VIVA LA FAMILIA Study in 2000-2005.

SETTING

This study was performed at the Children's Nutrition Research Center.

PARTICIPANTS

The study participants were 805 Hispanic nonoverweight and overweight children, ages 4-19 yr.

MAIN MEASURE

The main measure of the study was fasting serum adiponectin.

RESULTS

The heritability of serum adiponectin was 0.93 +/- 0.10 (P = 2.4 x 10(-40)). Adiponectin differed by age (P = 0.001), sex (P = 0.04), and weight (P = 0.001) status. Adiponectin levels declined with age, in association with changes in sex hormones and growth factors. Adiponectin was not associated with macronutrient intake, fitness, 24-h energy expenditure, or fat oxidation. Controlling for age, sex, and percent fat mass, adiponectin was inversely associated with homeostasis model of insulin resistance, triglycerides (TG)/high-density lipoprotein cholesterol (HDL-C), and systolic blood pressure (P = 0.001). Significant positive genetic correlations were detected between adiponectin and total cholesterol (rho(G) = 0.19), HDL-C (rho(G) = 0.32), low-density lipoprotein cholesterol (rho(G) = 0.24), and IGF-binding protein-1 (rho(G) = 0.39), and negative genetic correlations were detected between adiponectin and leptin (rho(G) = -0.30), TG (rho(G) = -0.21), TG/HDL-C (rho(G) = -0.33), and IGF-binding protein-3 (rho(G) = -0.32), indicating shared genetic components in their expression.

CONCLUSION

The high heritability of adiponectin and pleiotropy seen between adiponectin and leptin, growth factors, and lipids may play a role in the pathogenesis of cardiovascular disease and type 2 diabetes in overweight Hispanic children.

Anti-ganglioside antibody-mediated neuronal cytotoxicity and its protection by intravenous immunoglobulin: implications for immune neuropathies

Antibodies against GD1a, GM1 and related gangliosides are frequently present in patients with the motor variant of Guillain-Barré syndrome (GBS), and their pathological role in this variant of GBS is now widely accepted. However, two basic issues related to anti-ganglioside antibody-mediated neural injury are not completely resolved: (i) some anti-ganglioside antibodies can cross-react with glycoproteins and therefore the nature of antigens targeted by these antibodies is not well established; and (ii) although pathological studies suggest that complement activation occurs in GBS, experimental data for the role of complement remain inconclusive. To address these issues, we developed and characterized a simple anti-ganglioside antibody-mediated cytotoxicity assay. Our results demonstrate first, that both GBS sera containing anti-ganglioside antibodies and monoclonal anti-ganglioside antibodies cause neuronal cell lysis by targeting specific cell surface gangliosides, and secondly, that this cell lysis is complement dependent. In this assay, the GD1a cell membrane pool appears to be more susceptible to anti-ganglioside antibody-mediated injury than the GM1 pool. Further, human intravenous immunoglobulin (i.v.Ig), now a standard treatment for GBS, significantly decreased cytotoxicity in this assay. Our data indicate that the mechanisms of i.v.Ig-mediated protection in this assay include anti-idiotypic antibodies and downregulation of complement activation. This simple cytotoxicity assay can potentially be used for screening of (i) pathogenic anti-ganglioside antibodies in patients with immune-mediated neuropathies; and (ii) new/experimental therapies to prevent anti-ganglioside antibody-mediated neural injury.

Energy requirements of women of reproductive age

BACKGROUND

The energy requirements of women have been based on total energy expenditure (TEE) derived from the factorial approach or as multiples of basal metabolic rate (BMR).

OBJECTIVE

This study was designed to reevaluate the energy requirements of healthy, moderately active underweight, normal-weight, and overweight women of reproductive age.

DESIGN

The energy requirements of 116 women [n = 13 with a low body mass index (BMI), n = 70 with a normal BMI, and n = 33 with a high BMI] were estimated from TEE measured by the doubly labeled water method. Twenty-four-hour EE and BMR were measured by room respiration calorimetry, activity EE was estimated from nonbasal EE as TEE - BMR, and physical activity level was calculated as TEE/BMR. Body composition was derived from a multicomponent model. Fitness, strength, and physical activity level were assessed, and fasting serum indexes were measured.

RESULTS

Energy requirements differed among the low-BMI (8.9 +/- 0.9 MJ/d), normal-BMI (10.1 +/- 1.4 MJ/d), and high-BMI (11.5 +/- 1.9 MJ/d) groups (P = 0.02-0.001, all pairwise comparisons). Major predictors of BMR, 24-h EE, and TEE were weight, height, and body composition; minor predictors were fasting metabolic profile and fitness. Fat-free mass and fat mass accounted for the differences in EE seen between the BMI groups. The mean physical activity level of 1.86 suggested that the multiples of BMR used to estimate energy requirements have been underestimated.

CONCLUSION

Recommended energy intakes for healthy, moderately active women of reproductive age living in industrialized societies should be revised on the basis of TEE.

Gastric proteolysis in preterm infants fed mother's milk or formula

Gastric proteolysis is assumed to be low in the newborn (Britton & Koldovsky 1989). Postprandial pepsin output is significantly lower in preterm infants than adults, 589 vs. 3352U/kg, respectively (Armand et al. 1995, 1996). We now report on gastric proteolysis in preterm infants (gestation age, 29 weeks; postnatal age, 5-6 weeks) gavage-fed mother's milk or preemie formula. The data show that a) the nonprotein component is higher in human milk than formula, b) net proteolysis amounts to 15% of protein, c) gastric proteolysis is lower than lipolysis and, contrary to the latter, is not enhanced by milk feeding (Armand et al. 1996). We suggest that stomach pH, enzyme output, and food structure are the reasons for differences in gastric digestion of protein and fat in infants.

Forensic Issues in Pain: Review of Current Practice

Forensic activity in pain practice is reviewed with reference to the differing roles of the pain clinician and the independent expert. Ethical guidelines and recommendations for assessment, documentation, record review, and court testimony are discussed. Specific issues include the assessment of disability and impairment, malingering, and application of the Daubert standard in forensic pain practice. Examples of case law are reviewed for civil liability and CRPS, malpractice with opioid prescribing, and practice issues in a correctional setting.

Energy requirements derived from total energy expenditure and energy deposition during the first 2 y of life

BACKGROUND

Current recommendations for energy intake of children are derived from observed intakes. Deriving energy requirements on the basis of energy expenditure and deposition is scientifically more rational than is using the observational approach and is now possible with data on total energy expenditure (TEE), growth, and body composition.

OBJECTIVES

The objectives of this study were 1) to define energy requirements during the first 2 y of life on the basis of TEE and energy deposition; 2) to test effects of sex, age, and feeding mode on energy requirements; and 3) to determine physical activity.

DESIGN

TEE, sleeping metabolic rate, anthropometry, and body composition were measured in 76 infants. TEE was measured with doubly labeled water, sleeping metabolic rate with respiratory calorimetry, and body composition with a multicomponent model.

RESULTS

Total energy requirements were 2.23, 2.59, 2.97, 3. 38, 3.72, and 4.15 MJ/d at 3, 6, 9, 12, 18, and 24 mo, respectively. Energy deposition (in MJ/d) decreased significantly over time (P: = 0.001) and was lower in breast-fed than in formula-fed infants (P: = 0.01). Energy requirements were approximately 80% of current recommendations. Energy requirements differed by age (P: = 0.001), feeding group (P: = 0.03), and sex (P: = 0.03). Adjusted for weight or fat-free mass and fat mass, energy requirements still differed by feeding group but not by age or sex. Temperament and motor development did not affect TEE.

CONCLUSION

The TEE and energy-deposition data of these healthy, thriving children provide strong evidence that current recommendations for energy intake in the first 2 y of life should be revised.

Different effects of nocturnal parafunction on the masticatory system: the Weak Link Theory

It is proposed that damage to the masticatory system from intense parafunction can be assessed more accurately by the Weak Link Theory. The theory predicts that the more intense and the more prolonged the forces, the more the tendency of damage to either. 1. the periodontal tissue; 2. the teeth; or 3. the orofacial structures. To test the theory, 22 subjects were selected based on reports of nocturnal bruxism. Each was assessed for masticatory system breakdown on the Russell Periodontal Index, the Helkimo Dysfunction Index, and a Tooth Wear Index. A Bruxcore (Forgione, A. 1974 J Dent Res 53:127) was used to obtain an objective score of bruxism. Five of eleven subjects with mild bruxism scored high on only one index. Significantly more subjects (ten of eleven) with moderate to severe bruxism scored high on one index only.

Physiologic variations in dural venous sinus flow on phase-contrast MR imaging

OBJECTIVE

Our study quantifies normal physiologic variations of dural sinus flow using phase-contrast MR imaging.

SUBJECTS AND METHODS

Fifteen volunteers were imaged using nontriggered and triggered phase-contrast MR venography of the superior sagittal and transverse sinuses. Triggered scans were obtained during regular breathing; nontriggered scans were obtained during regular breathing, breath-holding, deep inspiratory breath-holding, and deep expiratory breath-holding. Analysis of variance, Bonferroni method, and Dunn post hoc analysis were used to determine any significant differences in the mean flow and velocity between the different breathing maneuvers. A paired t test was used to compare flow between sinuses during regular breathing.

RESULTS

Deep inspiratory breath-holding and deep expiratory breath-holding resulted in a significant decrease in blood flow and velocity in all dural sinuses compared with regular breathing. During deep inspiratory breath-holding, blood flow decreased 30.8% in the superior sagittal sinus, 19.7% in the left transverse sinus, and 19.1% in the right transverse sinus. Similarly, during deep expiratory breath-holding, blood flow decreased 30.2% in the superior sagittal sinus, 20.8% in the left transverse sinus, and 20.3% in the right transverse sinus. The sum of the flow in the transverse sinuses was significantly greater than in the sagittal sinus. Normal pulsatility of dural sinus blood velocity was also characterized for all measured sinuses.

CONCLUSION

Characterization of variations in dural sinus velocity and flow as a function of the cardiac cycle and breathing maneuvers, using phase-contrast MR imaging, may help separate physiologic from pathologic changes of flow resulting from conditions that influence the cerebrovascular circulation.

Protective function of human milk: the milk fat globule

Human milk contains many components that protect the newborn against infection at a time when the infant's own defense mechanisms are poorly developed. Fat is one of the major nutrients in human milk. The fat is contained within milk fat globules composed of a core of triglyceride and a membrane consisting of phospholipids, cholesterol, proteins, and glycoproteins. Both the membrane and the core components can provide protection against microorganisms. The major protective membrane glycoproteins, mucin, and lactadherin are resistant to conditions in the newborn's stomach and maintain their structure and function even at low pH and in the presence of the proteolytic enzyme pepsin. The core triglycerides upon hydrolysis by digestive lipases (especially gastric lipase, which is well developed in the newborn) produce free fatty acids and monoglycerides, amphiphylic substances able to lyse enveloped viruses, bacteria, and protozoa. Therefore, in addition to its nutritional value, the fat in human milk has a major protective function.

Dynamic T1-weighted spin-echo MR imaging: the role of digital subtraction in the demonstration of enhancing brain lesions

We compared subtracted and non-subtracted images obtained from a contrast-enhanced dynamic T1-weighted spin echo (SE) magnetic resonance (MR) technique for the demonstration of enhancing brain lesions with and without associated hemorrhage. Thirty-four patients with enhancing brain lesions or subacute parenchymal hematomas were imaged using a contrast-enhanced dynamic T1-weighted SE MR technique modified by a keyhole scheme. On-line digital subtraction was performed. Non-subtracted and subtracted dynamic scans were compared for conspicuity and contrast-to-noise ratios (CNRs) of enhancing brain lesions. The presence and pattern of enhancement in the subacute parenchymal hematomas were evaluated on the subtracted images. In all, 47 enhancing brain lesions were detected on both the non-subtracted and the subtracted images. The enhancing brain lesions were more conspicuous on the subtracted images (P < 0.05). There was an increase in CNRs of the enhancing lesions on the subtracted images compared with the non-subtracted ones (P < 0.001). Seventeen subacute parenchymal hematomas were detected on the non-subtracted images. The subtracted images demonstrated enhancement in 15 hematomas (8 rim enhancement only/7 both nodular and rim enhancement). Digital subtraction in contrast-enhanced dynamic T1-weighted SE MR imaging is helpful in demonstrating enhancing brain lesions with and without associated hemorrhage.

The effect of vertical dimension and mandibular position on isometric strength of the cervical flexors

This study compared the peak isometric strength of the cervical flexors in deep bite temporomandibular dysfunction (TMD) patients while biting in four bite positions: habitual occlusion, edge-to-edge, lateral shift and retruded. These values were then compared to those of the same subjects' bite positions elevated to a functional criterion (maximum isometric strength of the deltoid muscles). The mean height increase was 2.4 mm with a range of 1.5-3.8 mm. Fifteen of eighteen deep bite subjects met an inclusionary criterion, at least 13.3 Newtons (N) stronger cervical muscle strength with mandible relaxed open than habitual bite. Peak strength biting edge-to-edge was significantly greater than biting in habitual occlusion. Strength was found to increase significantly when biting in each of four mandibular positions when the bite was elevated to the functional criterion. The greatest strength was obtained from elevated habitual and edge-to-edge positions. The findings are of clinical significance, suggesting that cervical muscle isometric strength is affected by bite position and vertical dimension of occlusion. The results suggest that when biting, individuals with deep bite may be functioning at about 60% of their potential cervical flexor, isometric strength. The interaction between occlusal position, vertical dimension and cervical muscle function suggests a craniomandibular-cervical masticatory system.

Milk fat globule glycoproteins in human milk and in gastric aspirates of mother's milk-fed preterm infants

Human milk fat globule (HMFG) glycoproteins can prevent infections by microorganisms in breast-fed infants; the MUC-1 mucin inhibits binding of S-fimbriated Escherichia coli to buccal mucosa, and lactadherin may prevent symptomatic rotavirus infections. In this study, the survival of these HMFG glycoproteins in the stomach of human milk-fed preterm infants (gestational age = 27.5 +/- 0.4 wk) was assessed, and levels in their mothers' milk determined, using specific RIAs. Butyrophilin, a major component of HMFG membrane that has no demonstrated antimicrobial activity, was studied for comparison. The levels of mucin, lactadherin, and butyrophilin in 41 milk samples of 20 mothers were 729 +/- 75, 93 +/- 10, and 41 +/- 3 microg/mL, respectively. Mucin and lactadherin were significantly higher in early milk samples (<15 d postpartum) than in later milk samples (15-90 d postpartum), whereas butyrophilin showed no such difference. Significant amounts of mucin and lactadherin were found in almost all gastric aspirates of human milk-fed infants, even 4 h after feeding (mucin, 270 +/- 30 microg/mL; lactadherin, 23.2 +/- 4.4 microg/mL), whereas butyrophilin was rapidly degraded in the majority of aspirates. Western blot analysis demonstrated that the immunoreactive mucin, lactadherin, and butyrophilin in the milk-fed gastric aspirates had the expected native molecular weights. Mucin and lactadherin survived at all gastric pH values, whereas butyrophilin was found only at pH > 4. Neither lactadherin nor butyrophilin were detected in gastric aspirates of formula-fed infants (gestational age = 27.8 +/- 0.5 wk), whereas the very low level of mucin (9.1 +/- 1.1 microg/mL) in this group is presumably cross-reacting gastric mucin. These results demonstrate that two HMFG glycoproteins implicated in prevention of infection, MUC-1 mucin and lactadherin, survive and maintain their integrity in the stomachs of human milk-fed preterm infants.

Effect of increased maxillo-mandibular relationship on isometric strength in TMD patients with loss of vertical dimension of occlusion

The effect on isometric strength of the shoulders and limbs while biting in habitual occlusion, on a bite-elevating appliance and on a placebo appliance was analyzed. Twenty female volunteer patients, presenting with temporomandibular pain dysfunction syndrome and obvious loss of vertical dimension, served as subjects. All were weaker to the manual application of the isometric Deltoid Press (IDP) when biting, as opposed to maintaining the mandible in an unsupported rest position. Two intraoral appliances were fabricated for each subject: a bite-elevating appliance (BEA) set by a functional criterion of peak strength to the IDP and a placebo appliance which did not interfere with occlusion but was "set" with a mock IDP procedure. Testing was carried out by the Neuromuscular Research Testing Laboratory of the Neurology Department of Tufts New England Medical Center. Testing was independent of the dentist who fabricated and set the appliances. A standard neuromuscular test with the Maximal Voluntary Isometric Contraction apparatus was used to assess strength of right and left shoulder, elbow and knee flexion and extension as is routinely performed with all neuromuscular disease patients. Twelve strength tests were carried out for each of three conditions: 1. Baseline-biting in habitual occlusion; 2. Elevated-biting on the BEA; and 3. Placebo-biting with the placebo appliance inserted. The order of conditions 2 and 3 was counterbalanced without knowledge of the subjects. Twelve repeated measures ANOVAs (each subject as their own control) were conducted for each of the 12 strength measures. All F-tests indicated a significant main effect for treatment differences (p < 0.0001). Mean strength biting on the BEA was consistantly greater (p < 0.001) than Baseline or Placebo strength. Baseline and Placebo condition were equivalent. These findings confirmed previous observations at this TMD Center: individuals with loss of vertical dimension of occlusion respond to a bite raising appliance by increased isometric-strength.

The relationship between jaw posture and muscular strength in sports dentistry: a reappraisal

From the late 1970s until the early 1990s, there have been several reports of improved appendage muscle strength and athletic performance. Much of the criticism of using a mouthguard alone or in conjunction with a splint, such as a mandibular orthopedic repositioning appliance (MORA), to enhance athletic performance has been aimed at study designs, controls, periods of time, double blindness, and the placebo effect. Although it would appear that designing a study which pleases both clinician and researcher would be a difficult task, studies have been performed that do meet the "gold standard." The results favor the premise that jaw repositioning can enhance appendage muscular strength and athletic performance. Studies performed during the mid-1980s, and to which the scientific community refers to continually, on closer examination are flawed.

Effect of human milk or formula on gastric function and fat digestion in the premature infant

The effect of diet, human milk or formula, on gastric function (lipase and pepsin activity, pH, and volume) and intragastric digestion of fat was assessed in 28 appropriate for gestational age preterm infants (gestational age, 28.9 +/- 1.4, 29.1 +/- 0.9, 29.5 +/- 0.6 wk; birth weight, 1.00 +/- 0.14 to 1.18 +/- 0.07 kg). The infants were fed either human milk (n = 11), SMA Super Preemie formula (n = 9), or Similac, Special Care formula (n = 8). Fasting and postprandial activity of digestive enzymes, pH, and gastric volume (measured before or during 50 min after gavage feeding) did not differ as a function of diet among the three groups of infants. Gastric lipase output, 23.1 +/- 5.1, 28.3 +/- 6.6, and 22.5 +/- 6.4 (U/kg of body weight) in human milk-, SMA SP-, or Similac SC-fed infants was comparable to the gastric lipase output of healthy adults fed a high fat diet (22.6 +/- 3.0). Pepsin output was, however, significantly lower (597 +/- 77, 743 +/- 97, and 639 +/- 142 U/kg of body weight) in human milk-, SMA SP-, and Similac SC-fed infants) than in healthy adults (3352 +/- 753 U/kg). The hydrolysis of dietary fat was 1.7-2.5-fold higher (p < 0.01) in human milk-fed infants than in infants fed either formula. We conclude that differences in type of feeding, i.e. different fatty acid profiles (long chain or medium chain triglycerides), different emulsions (natural or artificial), and different fat particle sizes do not affect the level of activity of gastric enzymes. However, the triglyceride within milk fat globules appears to be more accessible to gastric lipase than that within formula fat particles. We suggest that the contribution of gastric lipase to overall fat digestion might be greater in the newborn (a period of pancreatic insufficiency) than in the adult.

Relationship of muscular strength to jaw posture in sports dentistry

From the late 1970s until the early 1990s there have been several reports of improved appendage muscle strength and athletic performance. Much of the criticism of using a mouthguard alone or in conjunction with a splint, such as a mandibular orthopedic repositioning appliance (MORA), to enhance athletic performance has been aimed at study designs, controls, periods of time, double blindness and the placebo effect. Although it would appear that designing a study that would please both clinician and researcher would be a difficult task, studies have been performed that do meet the "gold standard"; and the results favor the premise that jaw repositioning can enhance appendage muscular strength and athletic performance. Previous studies performed in the mid-1980s, and to which the scientific community refers to continually, on closer examination are flawed.

Whole-body irradiation transiently diminishes the adrenocorticotropin response to recombinant human interleukin-1 alpha

Recombinant human interleukin-1 alpha (rhIL-1 alpha) has significant potential as a radioprotector and/or treatment for radiation-induced hematopoietic injury. Both IL-1 and whole-body ionizing irradiation acutely stimulate the hypothalamic-pituitary-adrenal axis. We therefore assessed the interaction of whole-body irradiation and rhIL-1 alpha in altering the functioning of the axis in mice. Specifically, we determined the adrenocorticotropin (ACTH) and corticosterone responses to rhIL-1 alpha administered just before and hours to days after whole-body or sham irradiation. Our results indicate that whole-body irradiation does not potentiate the rhIL-1 alpha-induced increase in ACTH levels at the doses used. In fact, the rhIL-1 alpha-induced increase in plasma ACTH is transiently impaired when the cytokine is administered 5 h after, but not 1 h before, exposure to whole-body irradiation. The ACTH response may be inhibited by elevated corticosterone levels after whole-body irradiation, or by other radiation-induced effects on the pituitary gland and hypothalamus.

Clinical study of location and reproducibility of three mandibular positions in relation to body posture and muscle function

Clinical studies have confirmed the adequate reproducibility of both centric occlusion and centric relation when used as reference positions during treatment; however, the reproducibility of the neuromuscular position has been found inadequate. This study evaluated the location and reproducibility of these three mandibular positions in relation to body posture, sitting and supine, and bilateral muscle activity before and after the insertion of a flat mandibular positioning device equilibrated to balance the muscle functions, as shown by two electromyography biofeedback instruments. Intraoral recordings were made in 11 young subjects with complete natural dentition. Acrylic resin clutches that supported a screw point in the maxillary arch and painted glass in the mandibular arch were used and positioned not to interfere with the occlusion. The distances of the screw scratch from two of the edges of the painted glass were used to measure the anteroposterior and mediolateral locations with a micrometer. The reproducibility was evaluated by measuring the scratch surface by measuring the weight of the print cutouts made from photographs of the scratches taken with a stereoscope. The location and reproducibility of centric occlusion and centric relation were not affected by body posture. A more precise posterior neuromuscular position was obtained in the supine position. The insertion of a mandibular positioning device did not affect centric occlusion but gave a more precise centric relation. Neuromuscular position became as precise as centric occlusion and was located anteroposteriorly between centric occlusion and centric relation.

Systemically administered histamine H1 and H2 receptor antagonists do not block the ACTH response to bacterial lipopolysaccharide and interleukin-1

The administration of lipopolysaccharide (LPS) results in the activation of the hypothalamic-pituitary-adrenal axis (HPAA). We recently reported that the participation and interaction of LPS-induced proinflammatory cytokines were obligatory for the stimulation of adrenocorticotropic hormone (ACTH) release by LPS. LPS and LPS-derived cytokines also stimulate the release of histamine (HA). HA is a known hypothalamic neurotransmitter and activates the HPAA. Therefore, to elucidate the role of HA in LPS- and cytokine-induced ACTH release, we evaluated the effects of several HA H1 and H2 receptor antagonists on the ACTH response to LPS, recombinant human interleukin-1 alpha (rhIL-1 alpha) and HA in mice. Although all 3 of the H1 receptor antagonists administered (mepyramine (MEP), diphenhydramine (DPH) or promethazine (PMZ) were able to block the 10-min ACTH response to HA, only PMZ (a less selective H1 receptor antagonist than MEP) was able to reduce the LPS- or rhIL-1 alpha-induced ACTH responses. Ranitidine, a powerful and selective H2 receptor antagonist, had little effect on the LPS- and rhIL-1 alpha-induced ACTH responses, while metiamide (MET), a much less potent first-generation H2 receptor antagonist, substantially diminished ACTH release. The greater effectiveness of PMZ, in contrast to MEP or DPH, probably relates to the ability of phenothiazine derivatives to inhibit non-HA-dependent pathways involved in the stimulation of the HPAA by cytokines; the same may be true of MET.(ABSTRACT TRUNCATED AT 250 WORDS)

Strength and bite, Part 2: Testing isometric strength using a MORA set to a functional criterion

The effect on isometric strength of biting on three intraoral devices and habitual occlusion was analyzed. Only subjects who showed a relative weakness to the Isometric Deltoid Press (IDP) when biting as opposed to maintaining the mandible in an unsupported rest position were included in the study. Both in the original 35 subjects and the 23 subjects returning on the second day, performance wearing the appliance set by a functional criterion of peak strength (locking) to the IDP was significantly greater than wearing a placebo appliance and a bite raising appliance that deflected the mandible 1 mm to the left. Strength biting on the appliance set by a functional criterion was significantly greater than all these conditions. Strength biting in habitual trials that were matched with the deflection condition was found to be significantly greater than that biting in the placebo condition. It was concluded that a relationship does exist between bite and isometric strength. Previous speculation about the role of placebo effect was not substantiated by the data gathered in this experiment.

Pulmonary function and morbidity in textile mill workers

The study was conducted in a large cotton textile mill in Surat City. A selected number of 278 employees were evaluated for social, anthropological and pulmonary functions. No parameters except the period of exposure to dust reduced pulmonary function; it was statistically significant in the case of vital capacity and maximum breathing capacity. Out of 23.94% pulmonary morbidity observed, the byssinosis rate was 1.62.

Adherence of medium-chain fatty acids to feeding tubes of premature infants fed formula fortified with medium-chain triglyceride

Adherence of medium-chain triglyceride (MCT) oil to feeding tubes during gavage feeding of Enfamil formula was quantitated. Infants were fed similar volumes of either unfortified formula (n = 11) or MCT oil-fortified formula (0.5 ml/oz); either the MCT oil was mixed with the formula before feeding (n = 11) or the MCT oil was delivered into the feeding tube and then was followed by formula (n = 11). The fat residue in the feeding sets was quantitated by gravimetry, and individual fatty acids were characterized by gas-liquid chromatography. The data show that only trace amounts of lipid (0.23 +/- 0.04%) adhered to feeding sets during feeding of unfortified formula. Significantly more lipid (p less than 0.0005) adhered when formula was fortified with MCT oil, and the method of feeding greatly affected lipid adherence, i.e., 1.52 +/- 0.21% when the MCT oil was followed by formula versus 10.20 +/- 1.76% when the MCT oil was mixed with formula before feeding. Analysis of the fat residue of fortified formula showed that greater than 90% was composed of C8:0 and C10:0, the major fatty acid components of MCT oil. We suggest that care be exercised when fortifying infant formula with MCT oil.

Strength and bite, Part 1: An analytical review

The original clinical observations and research in the area of bite and strength enhancement studied individuals with obvious malocclusion and a subject population with mixed occlusions. An increase in isometric strength was obtained when biting on a K-MORA, an intraoral device that supports a mandibular position determined by a functional criterion. The criterion is a locking response to the Isometric Deltoid Press, a muscle challenge used by kinesiologists. Rather than replication with improved design, subsequent research (1) employed different mandibular positions based on therapeutic, electrical impulse or structural criteria; (2) tested mainly isokinetic strength; (3) referred to "strength" without qualification, implying more generalization than the findings actually allowed; (4) criticized and rejected positive findings by attributing strength increase to the placebo effect even though in no instance has the placebo effect been demonstrated in this field. Considering published and unpublished research on isometric strength and the irrelevance of many studies that found no difference in isokinetic strength, it is concluded that it is most probable that isometric strength is increased by the K-MORA in mixed populations.

Fat absorption in premature infants: medium-chain triglycerides and long-chain triglycerides are absorbed from formula at similar rates

Fat absorption from two different premature infant formulas and one full-term formula containing three different fat blends was investigated in two groups of premature infants. The first group of nine infants (gestational age, 29.1 +/- 0.88 weeks; postnatal age, 3.13 +/- 0.71 weeks) was fed alternately for 1 week each SMA preterm formula containing either high levels (50%) of medium-chain triglycerides (MCT) (6:0, 8:0, and 10:0) or high levels (86%) of long-chain triglycerides (LCT) (greater than or equal to C12). Except for fat blends, the formulas were otherwise identical. The second group of 11 infants (gestational age, 30.5 +/- 0.77 weeks, studied at a postnatal age of 4.33 +/- 0.91 weeks) was fed for 1 week a full-term infant formula, S-26, containing 98% LCT. Fat absorption (studied during a 3-day fat balance period) was similar irrespective of fat blend: 89.08 +/- 2.37% during feeding of preterm SMA, 50% MCT; 87.0 +/- 3.81% during feeding of preterm SMA, 86% LCT; and 83.00 +/- 2.89% during feeding of S-26, 98% LCT. Weight gain (grams per day) and increase in length (centimeters per day) were 23.2 +/- 1.7, 21.20 +/- 1.7, and 14.28 +/- 2.9, and 0.17 +/- 0.06, 0.16 +/- 0.04, and 0.22 +/- 0.07 during feeding of the three fat blends, respectively. Lipase activity levels in fasting gastric aspirates were higher during feeding of the LCT than the MCT formula. The possible stimulation of gastric lipase secretion secondary to long-chain fatty acid stimulation of cholecystokinin secretion might be related to the efficient digestion of formula fat, irrespective of triglyceride-fatty acid chain length.(ABSTRACT TRUNCATED AT 250 WORDS)

The impact of gestational length on human milk selenium concentration and glutathione peroxidase activity

Longitudinal changes in selenium (Se) and protein concentrations and glutathione peroxidase (GSH-Px) activity of milk collected from healthy mothers of term (n = 12), preterm (n = 10), and very preterm (n = 12) infants were assessed. All infants were size appropriate for gestational age. Milk samples representative of colostrum (d 3), transitional (d 7), and mature milk (d 21 and 42) were assayed. The content of Se in the colostrum secreted by mothers of preterm infants was significantly greater than the Se content of milk secreted by the same mothers at d 21 and 42 of lactation. Mothers of term and very preterm infants, however, produced colostrum with significantly higher levels of Se than milk produced at d 7 (p less than 0.05), d 21 (p less than 0.01), or d 42 (p less than 0.001). Significant differences between the protein concentrations measured in early lactation and in late lactation were evident in all maternal groups. Protein content did not differ significantly among groups at anytime during lactation. An age-related difference was detected in milk GSH-Px activities of mature milk (d 21). Mature milk produced by mothers of very preterm infants on d 21 of lactation contained significantly greater enzyme activity (p less than 0.05) than milk produced by mothers of term infants at the same stage of lactation. Activity of GSH-Px in milk from mothers of very preterm and preterm infants paralleled previously noted changes in long-chain polyunsaturated fatty acid content in human milk with the progression of lactation.(ABSTRACT TRUNCATED AT 250 WORDS)

Hyperalimentation-associated neonatal cholestasis: effect of oral gentamicin

The effect of oral gentamicin on the incidence of parenteral nutrition-associated cholestasis in preterm infants less than 1500 g birth weight was assessed retrospectively. Of 24 patients on parenteral nutrition for more than 10 days, 12 infants who received oral gentamicin (group I) for prophylaxis against neonatal necrotizing enterocolitis were compared to 12 infants who did not (group II). Both mean and peak direct bilirubin levels were significantly higher in group II. The increase in both mean and peak direct bilirubin levels after initiation of total parenteral nutrition (TPN) was significant in group II only. The incidence of cholestasis was significantly higher in group II than in group I. These results suggest that oral gentamicin may have a protective effect against parenteral nutrition-associated cholestasis in the newborn preterm infant.

Meningococcal meningitis in an industrial area adjoining Surat City--some clinico-epidemiological aspects

An industrial area with poor sanitation and inhabited by migrant, male predominant population, situated South to Surat City, experienced an outbreak of pyogenic meningitis during 1985-87. A total of 197 cases of meningitis with 34 deaths were reported during a period of 1 1/2 years. Neisseria meningitidis was the predominant pathogen isolated from 66 out of 138 CSF samples. Recently migrated males of productive age groups drawn from the States of Uttar Pradesh and Orissa were predominantly affected. Male to female ratio was found to be 7.2:1. Nearly 2/3rd of the cases were reported during the dry colder months of winter and spring. Pregnancy and childbirth appeared to be important predisposing factors in females. Nine cases were reported from the family contacts of cases. Majority of the cases were labourers doing manual work.

Lipases in human milk: effect of gestational age and length of lactation on enzyme activity

Human milk contains two lipases, bile salt-stimulated lipase (BSSL) and lipoprotein lipase (LPL). In the mammary gland, LPL provides long-chain fatty acid for milk fat synthesis. LPL has no known function in milk, but has been implicated in milk fat hydrolysis during cold storage. BSSL may have an important role in infant fat digestion. The aims of the present studies were to assess (1) the methodological validity of using whole milk to analyze BSSL activity, (2) the longitudinal variation of BSSL and LPL activity in the milk of mothers delivering premature and full-term infants, and (3) the stability of BSSL and LPL activity during cold storage. Diluted whole milk and purified BSSL were shown to have similar characteristics. LPL activity was equally stable at -20 and -70 degrees C, whereas BSSL activity was higher in milks stored at -70 than at -20 degrees C (38.8 +/- 0.88 vs 33.3 +/- 0.87 U/ml milk, respectively; 1U = 1 mumol free fatty acid release/min). Levels of BSSL activity in preterm and term milk were similar. LPL activity tended to be higher in term milk. Overall, BSSL activity showed significant longitudinal variation, being highest at 1 and 3 weeks of lactation (43.2 +/- 0.04 and 42.6 +/- 1.03 U/ml milk, respectively). For LPL, the longitudinal pattern of activity depended upon the length of pregnancy. Implications for infant nutrition and mammary gland biology are discussed.

Gastric lipolysis and fat absorption in preterm infants: effect of medium-chain triglyceride or long-chain triglyceride-containing formulas

The extent of gastric lipolysis, fat absorption, and infant weight gain was studied in 12 preterm infants (gestational age 28.75 +/- 0.50 weeks, postnatal age 6.08 +/- 0.81 weeks) fed medium-chain triglyceride or long-chain triglyceride formula for 1 week in a crossover design. The former formula contained 42% of 8:0 and 10:0 and 19% of 12:0, 14:0, and 16:0; the latter formula contained only 7% of 8:0 and 10:0 and 46% of 12:0, 14:0, and 16:0. Gastric aspirates were obtained on the second and third day of formula feeding for quantitation of lipase activity and of the extent of gastric lipolysis. Fat balance studies were conducted during the last three days of each feeding regimen. The study showed that (1) there was marked hydrolysis of formula fat in the stomach during feeding of either medium-chain triglyceride formula or long-chain triglyceride formula (20% and 16%, respectively); (2) lipase activity in the gastric aspirates was less during feeding of medium-chain triglyceride formula than before the meal, which suggested stimulation of lipase secretion by long-chain fatty acid released from long-chain triglyceride formula fat or more rapid binding of lipase to ingested lipid in the medium-chain triglyceride formula; (3) fatty acid distribution in glycerides and free fatty acids showed preferential release of medium-chain (8:0, 10:0) and long-chain unsaturated (18:1, 18:2) fatty acids in the stomach. The low content of 8:0 and 10:0 in gastric triglyceride and free fatty acids suggested that medium-chain fatty acids were absorbed directly in the stomach.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of total parenteral nutrition on lipase activity in the stomach of very low birth weight infants

Lipase activity was quantitated in gastric aspirates of 7 premature infants (gestational age 24-29 weeks) during periods of total parenteral nutrition (TPN), mixed parenteral nutrition and gavage feeding or exclusive gavage feeding. The infants were studied from birth until the establishment of exclusive gastric gavage feeding. Lipase activity in gastric aspirates (quantitated by the hydrolysis of 3H-triolein at pH 4.2 and expressed in nmol 3H-oleic acid released/min/ml gastric aspirate) did not differ significantly as a function of mode of feeding: 570 +/- 235 during TPN, 260 +/- 145 during mixed parenteral nutrition and gavage feeding, and 374 +/- 149 during exclusive gastric gavage feeding. The data suggest that, contrary to the intestine and pancreas, the digestive function of the stomach is not impaired during TPN in the very preterm infant.

Bile salt-stimulated lipase of human milk: characteristics of the enzyme in the milk of mothers of premature and full-term infants

Human milk contains a lipase (bile salt-stimulated lipase) that is considered to have an important role in infant fat digestion. In this study we compared the characteristics of bile salt-stimulated lipase activity in milk samples from mothers delivering prematurely (26-30 and 31-37 weeks of gestation) and in milk from mothers delivering at term (38-42 weeks of gestation). Preterm milks were collected at day 1-5 and during week 6 of lactation. Term milks were collected during week 6 of lactation. The characteristics of the enzyme (kinetics, enzyme concentration, pH optimum, and pH stability, effects of bile salt structure and concentration, eserine inhibition) were identical regardless of length of pregnancy or duration of lactation. Bile salt-stimulated lipase had a neutral to alkaline pH optimum (pH 7.3-8.6), was stable for 1 h at a wide pH range (pH 3.1-8.6), was active only in the presence of primary bile salts, and was inhibited by eserine. The data indicate that, following parturition at as early as 26 weeks of gestation, the mammary glands synthesizes bile salt-stimulated lipase with identical characteristics as does the mammary gland after a full-term pregnancy.