Serum leptin levels in girls with precocious puberty

Few data are available regarding leptin levels in children with different pubertal stages or with precocious puberty (PP). The aim of this study was to assess the changes in serum leptin levels in patients with PP. We studied 20 girls with PP, with Tanner stage II-III; the age at the beginning of pubertal signs ranged from 4.2 to 7.1 yr; all the girls had an advantaged bone age. Controls were subdivided in two groups: group 1: 20 pre-pubertal girls with the same chronological age of the patients, without any signs of pubertal development (Tanner stage I); group 2: 20 additional girls with the same bone age, pubertal stage and body mass index (BMI) of the girls with PP. Serum leptin levels in females with PP are similar to those found in subjects with normal puberty (9.0 +/- 0.8 vs 9.1 +/- 0.9 ng/ml; ns) and different from subjects with the same chronological age without activation of puberty (5.6 +/- 0.9 ng/ml, p < 0.001). In all groups leptin levels correlated significantly with BMI (girls with PP: r = 0.5 1, p < 0.02; control group 1 girls: r = 0.71; p < 0.0001; control group 2 girls: r = 0.49; p < 0.02), there was no significant relationship between leptin and activation of hypothalamic-pituitary-gonadal axis. Our results indicate that the serum leptin levels in the girls with PP are not significantly different from levels in healthy girls at a similar stage of pubertal development, suggesting that the relationship between serum leptin levels and BMI is also present in this pathological situation.     

Serum leptin levels in acute protein deprivation

BACKGROUND: Protein energy malnutrition (PEM) induces a host neuroendocrine response, reflected by significant elevations in circulating glucocorticoid levels and associated with metabolic and immune dysfunction. Leptin regulates food intake and body mass and has a significant impact on the hypothalamic-pituitary-adrenal axis (HPA). We hypothesized that leptin may be altered by and may play an important role in regulating the effects of PEM. METHODS: Female Balb/c mice were used. In experiment 1, mice were pair-fed either a protein-free (0% casein) or control (24% casein) diet for 7 days. In experiment 2, mice were implanted with either a placebo or corticosterone-releasing pellet and fed the control diet for 7 days. In experiment 3, adrenalectomized mice were pair-fed either the protein-free or control diet for 7 days. Serum corticosterone and leptin levels were measured in all experiments. RESULTS: PEM caused significant reductions in food intake, body weight, and total body fat, but not lean body mass. Serum corticosterone and leptin levels were significantly greater in mice fed the protein-free diet. Subcutaneous implantation of a corticosterone pellet in mice fed the control diet resulted in a significantly elevated serum leptin level compared with placebo-implanted controls. Bilateral adrenalectomy partially blunted the increased serum leptin in PEM. CONCLUSIONS: Leptin may be an important mediator of weight loss and decreased food intake in PEM. Elevated serum leptin in PEM may be secondary to elevated serum corticosterone, with other factors inherent in the host response to protein restriction also contributing to elevated serum leptin.     

Serum leptin concentrations in patients with short-bowel syndrome

BACKGROUND: Short-bowel syndrome is a state of severe malabsorption resulting from absence or removal of the small bowel for several causes. A number of short-bowel patients develop hyperphagia. Leptin, a protein secreted from adipose tissue, signals the amount of energy stores to the brain. OBJECTIVE: To study body composition and leptin regulation in short-bowel patients and to determine whether or not leptin concentrations are linked with hyperphagia. DESIGN: We studied 25 short-bowel patients (remnant bowel less than 150 cm) and 31 controls and 10 oral nutrition. Fifteen patients received total parenteral nutrition and 10 oral nutrition. Anthropometric measurements, body composition (by bioelectrical impedance), and cholesterol, triacylglycerol and leptin concentrations were studied in all subjects. RESULTS: There were no differences between short-bowel patients and controls in anthropometric variables, body composition, or leptin concentrations. Leptin concentrations were higher in short-bowel women than men (9.21+/-8.54 vs. 3.22+/-1.86 ng/ml, P=0.01). Leptin concentrations correlated positively with age (r=0.4, P=0.045), body mass index (r=0.52, P=0.007), fat mass (r=0.67, P=0.001) and body fat (r=0.68, P=0.0001); there were no correlations with other body composition parameters. We found no correlations between parenteral or oral nutrition and body composition parameters, or between leptin concentrations and the presence of hyperphagia. Logistic regression analysis showed that body fat correctly identified leptin concentrations in 60% of patients. CONCLUSIONS: Body composition, leptin concentrations and leptin regulation in patients with short-bowel syndrome are similar to those of controls. Leptin concentrations do not correlate with hyperphagia in short bowel-patients.     

营养不良儿童血清瘦素水平与BMI、能量摄入的相关性分析

【目的】　探讨营养不良儿童血清瘦素水平的变化及其与能量摄入的相关性。　【方法】　检测32例营养不良患儿的空腹血清瘦素水平、体质指数(body mass index,BMI)、能量摄入量,并与32例健康儿童比较,同时分析血清瘦素水平与BMI、能量摄入的相关性。　【结果】　①病例组与对照组间的血清瘦素水平比较有统计学差异(F=4.574,P<0.05),病例组明显降低;②病例组中患儿的血清瘦素水平与BMI、能量摄入均有显著相关性(P<0.05);对照组中血清瘦素水平与BMI存在显著相关性(P<0.05), 但血清瘦素与能量摄入无显著相关性(P>0.05) 。　【结论】　营养不良儿童血清瘦素水平明显降低;其低下的原因,除了患儿脂肪含量下降致瘦素分泌减少外,还与能量摄入的减少有关。     

Serum leptin levels in overweight children and adolescents

Leptin is an adipocyte-secreted hormone which plays a key role in energy homeostasis. Our aim was to determine the relationship between serum leptin and clinical and biochemical features in overweight children and adolescents. Overweight children and adolescents followed in this Unit with serum leptin ascertained were included. Clinical, biochemical and abdominal ultrasound data were analysed. Statistical analysis was performed by t test, chi2, Pearson's correlation and linear regression. One outlier of serum leptin was excluded to perform correlation and regression. Serum leptin was determined in 357 patients. At the first visit, the mean age was 9.5 (sd 3.2) years and mean BMI z-score was 1.72 (sd 1.34) (girls 1.71 (sd 1.16); boys 1.72 (sd 1.11)). Serum leptin levels were significantly related to: sex (mean: girls 48.0 ng/ml, boys 34.4 ng/ml; P = 0.003); Tanner stage (mean: I-II 37.0 ng/ml, III-V 45.2 ng/ml; P = 0.035); systolic blood pressure (mean: normal 41.3 ng/ml, high 44.0 ng/ml; P = 0.009); BMI z-score (r 0.136; P = 0.010); C-peptide (r 0.17; P = 0.002); insulin (r 0.34; P < 0.001); homeostasis model assessment of insulin resistance (HOMA-IR) (r 0.25; P < 0.001) and aspartate aminotransferase (r - 0.12; P = 0.023). In the multivariate analysis (with leptin as the dependent variable and sex, Tanner stage, BMI z-score, systolic blood pressure, aspartate aminotransferase, C-peptide, insulin and HOMA-IR as independent variables), sex and BMI were determinant factors. The present study in overweight children and adolescents showed that being female and greater BMI were significantly and independently associated with increased serum leptin. In this large cohort other associations with leptin described in the literature can be discharged.     

Serum leptin and insulin levels during chronic diurnal fasting

Ramadan fasting is a unique model that is associated with restriction of the timing of food and fluid intake food from dawn to sunset and reduction in meal frequency and sleep duration. Leptin levels are thought to play a role in long-term regulation of caloric intake and fat deposition. However, the long-term changes in leptin levels during this pattern of fasting are not known. The study was conducted on lean (N=6, BMI=22.5+/-0.4) and obese (N=18, BMI=33.1+/-1.0) healthy female volunteers. Fasting serum levels of leptin, insulin and glucose were estimated at baseline (day 1), days 14 and 28 of the month of Ramadan and 2 weeks after Ramadan. Baseline serum levels of leptin were significantly higher in obese (13.5+/-1.96 microg/L,P<0.05) compared with lean subjects (9.60+/-0.80 microg/L) and correlated positively with body fat (r=0.82, P=0.0004). Serum leptin levels exhibited a significant and comparable increase by 39% and 37% throughout the month in lean and obese subjects, respectively. In addition, a significant correlation (r=0.52, P=0.003) was found between changes in serum leptin and serum insulin levels. We conclude that chronic diurnal fasting is associated with significant elevations in serum leptin. These elevations appear to be mediated by changes in serum levels of insulin. These data support the role of insulin in the long-term regulation of leptin secretion during chronic diurnal fasting followed by nocturnal eating during the month of Ramadan.     

Serum leptin levels in healthy adolescents: Effects of gender and growth

Objectives The purposes of this paper were to evaluate the serum leptin levels in healthy adolescents and to establish standard age variation curves. Methods Nine hundred six (414 boys and 492 girls) healthy adolescents were investigated. The maximum increment age in height (MIA) was identified in 124 boys and 130 girls. The menarcheal age (MA) was obtained for 130 girls. Fasting leptin levels were measured by enzyme immunoassay. The MIA was calculated by proportional allotment of yearly height increments. Results Serum leptin levels did not change in boys and girls from the ages of 9 to 11. They decreased after the age of 11 in boys, while they increased in girls. Stepwise multiple regression analysis revealed that serum leptin levels were closely related to pubertal stage. The levels decreased remarkably after MIA in boys and increased remarkably after MA in girls. We drew standard age variation curves of serum leptin levels by calculating the 25th, 50th and 75th percentiles for each age in both boys and girls. The percentile curves for boys were divided into pre-MIA and post-MIA curves. Those for girls were divided into pre-MA and post-MA curves. Conclusion We have devised a potentially useful method for evaluating serum leptin levels in adolescents considering the effects of gender and growth.     

煤工尘肺患者血清中抵抗素和瘦素水平及临床意义

目的 探讨煤工尘肺患者血清中抵抗素和瘦素水平及意义.方法 选择85例煤工尘肺患者(煤工尘肺组)作为观察对象,并以46例井下非尘肺工人(井下对照组)及40例井上非尘肺工人(井上对照组)作为对照,采用酶联免疫吸附双抗体夹心法检测血清中抵抗素和瘦素水平,并分析与体重指数(BMI)的关系.结果 与井上对照组及井下对照组比较,煤工尘肺患者血清中抵抗素和瘦素水平均明显降低,差异均有统计学意义(P《0.01);BMI较差及正常的煤工尘肺患者血清中抵抗素、瘦素水平明显低于井上对照和井下对照,差异有统计学意义(P《0.05).抵抗素和瘦素均与BMI呈正相关关系(r=43、r=47,P《0.01).结论 煤工尘肺患者血清中抵抗素和瘦素水平下降,BMI较差时下降更明显.     

三氯乙烯药疹样皮炎患者细胞因子水平分析

目的 探讨三氯乙烯(TCE)药疹样皮炎患者血清γ干扰素(IFN-γ)、肿瘤坏死因子(TNF-α)、白细胞介素4(IL-4)和白细胞介素10(IL-10)细胞因子水平的变化。 方法 采用酶联免疫吸附法(ELISA)测定52例患者和52例正常人血清中IFN-γ、TNF-α、IL-4、IL-10水平,并比较其水平差异,同时分析患者各细胞因子水平的相关性。 结果 病例组血清中IFN-γ、TNF-α、IL-4、IL-10水平[中位值(范围)]分别为20.59(12.64~198.00)、53.46(26.14~306.60)、28.05(12.83~256.36)、12.77(4.48~245.05) ng/L,对照组分别为13.62(6.03~28.18)、19.97(11.72~43.81)、12.34(10.39~22.39)、5.63(2.77~18.77) ng/L,以上4种结果在两组间比较,差异均有统计学意义(z=-5.649、-5.891、-5.416、-5.264,P<0.01);病例组血清中IFN-γ、TNF-α、IL-4、IL-10四种细胞因子水平均相互呈正相关(P<0.01)。 结论 IFN-γ、TNF-α、IL-4、IL-10在TCE药疹样皮炎发生过程中具有重要意义,可用于预测工人发病倾向以及发病趋势。     

Serum antioxidant vitamin levels in patients with coronary heart disease

The aim of this study was to investigate anthropometric measurements, body composition, and serum antioxidant vitamin levels in men with coronary heart disease (CHD). Thirty-five men with CHD and 31 men without CHD, aged 40 - 65 years, were included this study. Dietary records and anthropometric measurements of each participant were recorded by researchers and serum antioxidant vitamin levels and lipid profiles were analyzed. Fat mass (FM) and the percentage of fat mass (FM%) in men with CHD was higher than in men without CHD (p < 0.05). Lipid profiles were found to be similar in both groups, with the exception of high-density lipoprotein cholesterol (HDL-C). Men with CHD had lower HDL-C levels than men without CHD (p < 0.05). When the antioxidant vitamin intake of participants was investigated, vitamin E intake in men without CHD was found to be less than in men with CHD (p < 0.05). However, serum vitamin A, vitamin E, and vitamin C levels in men with CHD were found to be lower than in men without CHD (p < 0.05). Based on the results of this study, we propose that high FM, low HDL-C, and low serum antioxidant vitamin levels could be important risk factors for CHD.     

Serum leptin levels and their association with several factors related to arteriosclerosis among medical students in Japan

The association between serum leptin levels and several factors related to arteriosclerosis were studied in subjects who were Japanese medical students taking no medications. The group was comprised of 75 males and 35 females. The age distribution in males was 21.4 to 29.8 years (median age, 24.0 years) and in females was 21.3 to 29.9 years (median age, 22.9 years). Statistical analyses were performed using the Wilcoxon rank sum test and Spearman correlation. Median levels of serum leptin were 3.3 ng/ml in males and 7.6 ng/ml in females. The largest correlation observed was widi percent body fat irrespective of sex [males; r=0.775, p<0.001, females; r=0.553, p<0.001]. However, body mass index (BMI) was similarly well correlated with serum leptin [r=0.631, p<0.001] in males but not in females [r=0.305, p=0.075]. A negative correlation was observed between high density lipoprotein cholesterol (HDL-C) and leptin in both sexes [males; r=-0.298, p<0.01, females; r=-0.363, p<0.05] .respectively. Percent body fat, BMI, diastolic blood pressure, apolipoprotein B, and HDL-C were the most significant factors in males. Percentage of body fat and HDL-C were the most important factors in females.     

Changes in serum leptin levels in chronic renal failure patients with metabolic acidosis.

OBJECTIVE: To examine the relationship between serum leptin levels (SLL) and metabolic acidosis in patients with chronic renal failure (CRF). DESIGN: SLL in control patients and in predialysis patients with CRF were measured and compared. SLL before and after correction of acidosis in patients with CRF were also compared. Patients and Controls: Twenty-five patients with CRF (10 men and 15 women) aged 51.2 +/- 10.4 years and control patients (healthy subjects, 23 men and 25 women) aged 42.1 +/- 12.6 years were studied. INTERVENTION: Five percent sodium bicarbonate (NaHCO(3), 2 to 3 mL/kg) was intravenously infused on the morning of the first day of treatment. NaHCO(3) was taken orally at a dosage of 50 to 200 mg/kg/d for 3 to 5 days thereafter. Main Outcome Measure: SLL before and after NaHCO(3) treatment was measured by radioimmunoassay, and blood gas was measured before and after correction of metabolic acidosis in patients with CRF. RESULTS: SLL in the normal control group (n = 48) was 10.04 +/- 7.0 ng/mL and was realated to body mass index (BMI) (P =.0331). SLL in men (n = 23) was lower than that in female controls (n = 25, P <.01). SLL in patients with CRF (n = 25) before (plasma HCO(3)(-), 13.03 +/- 3.05 mmol/L) and immediately after improvement of metabolic acidosis (plasma HCO(3)(-), 18.35 +/- 4.21 mmol/L) was 14.52 +/- 9.27 ng/mL and 15.34 +/- 11.89 ng/mL (P >.05), respectively. SLL measured 3 to 5 days after treatment for metabolic acidosis (plasma HCO(3)(-), 20.46 +/- 4.03 mmol/L) was 19.33 +/- 14.58 ng/mL, which was significantly higher than that in the normal control group and that in acidotic patients before NaHCO(3) treatment (P <.01). CONCLUSIONS: SLL in acidotic patients with CRF were comparable to that in control subjects, and SLL was significantly increased after correction of metabolic acidosis in patients with CRF. The preliminary results suggest that hyperleptinemia in patients with CRF may be masked by metabolic acidosis and that metabolic acidosis may inhibit leptin synthesis or secretion. Further studies are needed to clarify the mechanisms.     

Serum magnesium levels in nursing home patients

The elderly nursing home patient is at risk for hypomagnesemia due to poor nutritional intake, multiple chronic disease states, and polypharmacy. In order to assess the need to screen for magnesium deficiency in a long-term care setting, serum magnesium levels were determined in 75 nursing home patients. Mild hypomagnesemia was observed in 3 of the patients, all with poor eating habits. Diuretic use, although common, was not associated with magnesium deficiency. Routine screening for hypomagnesemia in nursing home patients with adequate nutritional intake does not appear warranted.