Relationship between obesity and pulse pressure in children: results of the National Health and Nutrition Survey (NHANES) 1988–1994

BackgroundObesity is a known cardiometabolic risk factor in children. In adults, pulse pressure (PP) is a known predictor and a risk factor of cardiovascular (CV) diseases. In this study, we examined the association between measures of obesity and PP in children.MethodsA retrospective analysis of 4667 children ages 6–17 years from the National Health and Nutrition Survey (1988–1994) was performed. We defined wide PP as 4th quartile PP and high waist circumference (WC) as >75th percentile based on age and gender.ResultsThere were 51% boys, 74% whites, 16% blacks, 10% Hispanics, 12% obese, 26% with high WC, 26% with wide PP, and 9% with high blood pressure (BP). Prevalence of wide PP was high among obese children. A significantly higher mean PP was observed in boys, Blacks, obese, those with high WC and high BP. The adjusted odds ratio (OR) for wide PP was higher in boys, Blacks, and those with high WC.ConclusionThere was a statistically significant independent association observed between wide PP and high WC, but not with obesity based on BMI. Further exploration of wide PP as a CV risk factor in childhood and its relationship to CV outcomes appears warranted.     

Characterization of the p67phox gene: genomic organization and restriction fragment length polymorphism analysis for prenatal diagnosis in chronic granulomatous disease

The genetic defect in the p67phox-deficient form of chronic granulomatous disease (CGD) follows an autosomal recessive pattern of inheritance. When genomic DNA from normal individuals is digested with HindIII and probed with p67phox cDNA an allelic restriction fragment length polymorphism (RFLP) of 4.0 kb or 2.3 kb is detected. We cloned and characterized the p67phox gene using the cDNA and sequenced the exon/intron boundaries, mapping 16 exons on the 40-kb gene. The polymorphic region was then sequenced to identify the inheritance pattern of amniocentesis-derived fetal cells by genomic amplification. The proband, a 9-year-old female patient with p67phox-deficient CGD, and her phenotypically normal mother are homozygous for the RFLP marker, whereas the father and two brothers are heterozygous. The fetus was shown to be heterozygous as well, showing it had inherited at least one normal p67phox gene from the father and that it was predicted to have a normal phenotype. Cord blood samples at birth showed normal oxidative function. Amplification allows rapid detection of the inheritance pattern for fetal diagnosis in informative families. We report the genomic structure of p67phox and an amplification-based method for detection of the marker on chromosome 1q25, used here for prenatal diagnosis of CGD.     

Effect of salt loading on nitric oxide synthase expression in normotensive rats

Elevation of arterial blood pressure (BP) with high salt intake in Dahl salt-sensitive rats is associated and perhaps, in part, due to downregulation of renal and vascular production of nitric oxide (NO) and nitric oxide synthase (NOS) expressions. Several recent studies have revealed a significant increase in BP in Sprague-Dawley rats on high salt intake. Given the apparent salt sensitivity of Sprague-Dawley rats, we hypothesized that chronic high salt intake may affect NO system in these rats in a manner resembling that reported in salt-sensitive (not salt-resistant) Dahl rats. The effects of a high salt diet (chow containing 8% NaCl) of 48-h or 3-week duration was studied on immunodetectable endothelial (eNOS), inducible (iNOS), and neuronal (nNOS) NOS expressions of relevant organs in male Sprague-Dawley rats. The results were compared with those obtained in the control animals fed a regular no-added salt diet (0.2% NaCl). Consumption of a high salt diet for 3 weeks induced hypertension (HTN) (158 +/- 6 v 115 +/- 5 mm Hg, P < .01) and widespread downregulation of iNOS expression in renal cortex, renal medulla, aorta, and heart. Similarly, chronic salt loading resulted in marked downregulation of eNOS expression in renal cortex and aorta and lowered expressions of nNOS in the brain, renal cortex, and renal medulla. In comparison, short-term salt loading resulted in significant reduction of iNOS in the renal cortex and aorta and of eNOS in the aorta together with significant elevation of nNOS expression in renal medulla and brain. Thus, chronic consumption of a high salt diet resulted in moderate HTN in normotensive Sprague-Dawley rats. This was accompanied by widespread downregulation of various NOS isotypes that undoubtedly contributed to the development and maintenance of HTN in this model.     

Prevalence of intestinal parasitic pathogens among HIV-positive individuals in Iran

Parasites are important enteric pathogens among patients with human immunodeficiency virus (HIV) infection. There have been very few reports on the prevalence of intestinal parasites among such patients in Iran. To determine the prevalence of intestinal parasites among HIV-positive individuals, we collected single stool samples and analyzed them for detection of various intestinal parasites from 206 HIV-positive individuals with different immune status visited in different medical centers in Iran. The data were tested for statistical significance with chi(2) and Mann-Whitney U tests. The overall prevalence of intestinal parasites was 18.4% (95%CI: 13.7, 24.3). More specifically, the following parasites were identified: Giardia lamblia (7.3%), Blastocystis hominis (4.4%), Entamoeba coli (3.9%), and Cryptosporidium parvum (1.5%). Other parasites observed included Strongyloides stercoralis and Hymenolepis nana in two cases and Dicrocoelium dendriticum in one. Of the 38 patients who tested positive for intestinal parasites, 15 (39.2%) had diarrhea. Intestinal parasites were significantly more common among patients with diarrhea than those without (P < 0.001). Further, CD4 counts were significantly lower among individuals with diarrhea than those without (P < 0.001). This study highlights the importance of testing for intestinal parasites among Iranian HIV-positive patients, especially those with low immunity presenting with diarrhea.     

The Effect of a Constant Electrical Field on Osseointegration after Immediate Implantation in Dog Mandibles: A Preliminary Study

PURPOSE: The long time span between insertion of implants and functional rehabilitation often inconveniences patients. Accelerating bone growth around dental implants can shorten this time span. This in vivo study evaluated the effect of a constant electrical field on bone growth around dental implants. MATERIALS AND METHODS: Four mongrel dogs were used in this study. Sixteen dental implants were placed immediately after extraction of the first premolar and molar teeth. A constant electrical field (CEF) generator was placed in the mucoperiostal pouch created from the subperiostral dissection under the inferior border of the dog's mandible and connected to the experiment side fixtures. CEF provided 3 V of electrical potential during osseointegration. Histologic sections were stained with hematoxylin-eosin and observed under light microscopy. The sections were analyzed histomorphometrically to calculate the amount of newly formed bone. Statistical analysis was performed with SPSS 11.0 computer software (alpha= 0.05). RESULTS: At the end of the first stage of the osseointegration (90 days) CEF group sections showed enhanced growth of the trabeculae compared with the control group. Statistical analysis revealed significant differences between experimental and control groups. Bone contact ratio was statistically significant in the experimental group (p= 0.001). An increase in the local bone formation and bone contact ratio was observed with direct electrical stimulation of the implant and the bone area around the implant. CONCLUSION: Minimal direct electrical current, which can produce an electrical field around the implant, can increase the amount of bone formation and decrease the time of osseointegration.     

Intestinal absorption and biliary secretion of cholesterol in rats with nephrotic syndrome

Background: Nephrotic syndrome (NS) results in hypercholesterolemia which is attributed to increased production and decreased removal of cholesterol-rich lipoproteins. Adjustments in intestinal absorption are reportedly involved in cholesterol homeostatis. We therefore, studied the intestinal absorption and biliary excretion of cholesterol in NS. Methods: We studied intestinal absorption (by in vivo perfusion and in vitro everted sac incubation techniques) and biliary secretion (by common bile duct cannulation) of cholesterol in rats with puromycin-induced NS. The results were compared with those obtained from pair-fed control (PF) animals, those given free access to food (NL) or those fed a hypercholerolemic diet (H-chol group). Micellar solutions of Krebs' phosphate buffer containing trace amounts of [¹⁴C]inulin and [³H]cholesterol, as well as different concentrations of unlabeled cholesterol, were used for absorption studies. Results: The NS and H-chol groups showed severe and comparable hypercholesterolemia. No significant difference was found in the rate of biliary cholesterol secretion among the study groups. Likewise, the rates of in vivo and in vitro cholesterol absorptions in the NS and H-chol groups were comparable with one another and similar to those found in the NL and PF groups. The rate of in vitro cholesterol absorption was directly proportional to its concentration in the incubation media at low concentrations. However, the absorption rate showed a pattern consistent with saturable transport at high cholesterol concentrations in all groups. Conclusions: We conclude that intestinal absorption and biliary secretion of cholesterol are not appreciably influenced by either nephrotic or diet-induced hypercholesterolemia in rats. The data further suggest that cholesterol absorption may be a saturable process.     

Antioxidant therapy potentiates antihypertensive action of insulin in diabetic rats

BACKGROUND: Poorly controlled longstanding diabetes frequently results in sustained hypertension (HTN) which plays a major role in the pathogenesis of diabetic nephropathy. In addition, hyperglycemia, per se, causes a reversible rise in blood pressure (BP) and increases production of reactive oxygen species (ROS). Increased ROS activity may raise BP by promoting inactivation of nitric oxide (NO) and/or nonenzymatic generation of vasoconstrictive prostaglandins from peroxidation of arachidonic acid. Therefore, we hypothesized that antioxidant therapy may enhance the BP-lowering effect of glycemia control with insulin replacement in diabetes. METHODS: Male Sprague-Dawley rats were rendered diabetic by streptozotocin administration and randomized to untreated, antioxidant-treated (vitamin E-fortified food, tocopherol 5000 U/kg chow and vitamin C-fortified H2O, 1000 mg/L), insulin-treated and insulin plus antioxidant-treated groups. Normal rats fed a regular diet or antioxidant-fortified diet served as controls and monitored for 4 weeks. RESULTS: The diabetic animals showed marked hyperglycemia, HTN, proteinuria, depressed tissue glutathione level and elevated plasma lipid peroxidation product, malondialdehyde (MDA) denoting increased ROS activity. Insulin therapy alone resulted in significant, but incomplete reduction in BP and plasma MDA but not proteinuria. Antioxidant therapy alone had no effect on the measured parameters in either the diabetic or control animals. However, combined insulin and antioxidant therapies normalized BP, plasma MDA and urinary protein in the diabetic animals. As expected, uncontrolled diabetes resulted in glomerular hyperfiltration which was partially reversed by insulin therapy, but was unaffected by antioxidant therapy. CONCLUSION: Uncontrolled hyperglycemia in the early phase of diabetes was associated with elevated plasma MDA, HTN and proteinuria. Insulin therapy alone resulted in significant but incomplete reduction of plasma MDA and BP. Antioxidant therapy which was ineffective when given alone, normalized plasma MDA, BP and reduced urinary protein excretion when combined with insulin treatment.