妊娠高血压外周血中促Th2的细胞因子水平及IL-2／IL-10平衡的临床意义

目的：检测妊娠高血压患者外周血中促Th2的分子IL-4、IL-2与IL-10的水平,探讨IL-2／IL-10在妊高症中的临床意义。方法：选择40例未妊娠妇女为对照组,30例正常妊娠妇女为妊娠组,28例妊娠高血压患者为妊娠高血压组,ELISA检测血清中IL-4、IL-2和IL-10的水平。结果：与对照组外周血中IL-4水平（0．53±0．04）pg／ml相比：正常妊娠组IL-4水平升高至（0．91±0．03）pg／ml（P〈0．05）,妊娠高血压组IL-4水平（0．67±0．35）pg／ml升高但明显低于正常妊娠组（P〈0．01）。与对照组外周血中IL-2水平（0．41±0．05）pg／ml相比：正常妊娠组IL-2水平升高至（0．82±0．11）pg／ml（P〈0．01）;妊娠高血压组IL-2水平高达1．57±0．22（pg／m1）明显高于其它两组（P〈0．01）。妊娠高血压组外周血中IL-10水平明显低于正常妊娠组IL-10水平（P〈0．01）;妊娠高血压组外周血中IL-2／IL-10比值明显高于于对照组及正常妊娠组的比值。结论：妊娠高血压患者外周血中细胞因子IL-2和IL-10分泌异常且诱导Th2细胞产生的IL-4降低,打破Th1／Th2平衡,致使Th1型免疫反应增强,使早孕期滋养细胞受到免疫损伤以致侵入能力下降,导致妊娠期高血压疾病的发生。     

A comparison between the concentration of prostaglandin F in human plasma and serum

The concentration of prostaglandin F (PGF) has been measured in serum and plasma samples prepared under different conditions from the antecubital vein blood of 4 non-pregnant and 7 pregnant women. Prostaglandin F concentrations were less than 41 pg/ml in 19 samples of serum or plasma prepared by centrifugation within 30 minutes of collection. When the blood was allowed to clot at room temperature for 24 hours, highly variable, but usually markedly increased concentrations of PGF (<30 - 3020 pg/ml) were found in the serum. Plasma obtained from blood which stood at 23°C for 24 hours contained undetectable amounts of PGF in 4 out of 6 samples and less than 75 pg/ml in the 2 remaining samples. Plasma and serum obtained from blood which stood at 4°C for 24 hours contained less than 45 pg PGF/ml. These results show that (i) incubation of blood at room temperature may markedly elevate concentrations of PGF in serum, (ii) plasma samples rather than serum should be used for measurements of PGF concentrations.     

Obestatin, acylated and total ghrelin concentrations in the perinatal rat pancreas

BACKGROUND: Ghrelin and obestatin are encoded by the preproghrelin gene and originate from posttranslational processing of the preproghrelin peptide. The fetal rat pancreas contains acylated and desacylated ghrelin peptides, as well as growth hormone secretagogue receptor -1a mRNA. Acylated ghrelin inhibits insulin secretion. We investigated the plasma and tissue ontogeny of ghrelin and obestatin in the rat. METHODS: We measured obestatin and acylated and total ghrelin concentrations in plasma, pancreas and stomach from rat fetuses (F20) and neonates at postnatal day (PN) 1, 6, 12 and 21). RESULTS: Overall, obestatin concentrations were markedly lower than total ghrelin concentrations. In plasma, total ghrelin concentrations decreased abruptly after birth (p < 0.05), contrasting with a 3 times increase in the concentration of acylated ghrelin between F20 and PN1 (p < 0.05). In pancreas, total ghrelin and obestatin concentrations decreased progressively from PN1 to PN21 but acylated ghrelin concentrations increased 6-7 times from F20 (18 [6] pg/ml) to PN6 (122 [59] pg/ml). The percent of acylated ghrelin increased from 1.8 (0.6) at F20 to 39.7 (13.0) % of total ghrelin immunoreactivity at PN12 (p < 0.05). There were significant positive correlations between postnatal obestatin, acylated or total ghrelin and insulin concentrations in the pancreas (all p < 0.02, r(2) > 0.21) and between postnatal total ghrelin and obestatin (in pancreas, r(2) = 0.37) or acylated ghrelin (in stomach, r(2) = 0.27) (p < 0.001). CONCLUSION: Ghrelin and obestatin are present in the perinatal pancreas where they could potentially affect insulin secretion.     

Plasma obestatin levels in normal weight, obese and anorectic women

Obestatin is a recently discovered peptide produced in the stomach, which was originally described to suppress food intake and decrease body weight in experimental animals. We investigated fasting plasma obestatin levels in normal weight, obese and anorectic women and associations of plasma obestatin levels with anthropometric and hormonal parameters. Hormonal (obestatin, ghrelin, leptin, insulin) and anthropometric parameters and body composition were examined in 15 normal weight, 21 obese and 15 anorectic women. Fasting obestatin levels were significantly lower in obese than in normal weight and anorectic women, whereas ghrelin to obestatin ratio was increased in anorectic women. Compared to leptin, only minor differences in plasma obestatin levels were observed in women who greatly differed in the amount of fat stores. However, a negative correlation of fasting obestatin level with body fat indexes might suggest a certain role of obestatin in the regulation of energy homeostasis. A significant relationship between plasma obestatin and ghrelin levels, independent of anthropometric parameters, supports simultaneous secretion of both hormones from the common precursor. Lower plasma obestatin levels in obese women compared to normal weight and anorectic women as well as increased ghrelin to obestatin ratio in anorectic women might play a role in body weight regulation in these pathologies.     

Bolus administration of obestatin does not change glucose and insulin levels neither in the systemic nor in the portal circulation of the rat

Obestatin is a second peptide derived from the preproghrelin polypeptide. It was originally thought to have anorexigenic effects, thereby functioning as an antagonist of ghrelin. However, this has been a subject of debate ever since. Since acylated ghrelin strongly induces insulin resistance, it could be hypothesized that obestatin plays a role in glucose homeostasis as well. In the present study we evaluated the effect of obestatin on glucose and insulin metabolism in the systemic and portal circulation. Obestatin 200 nmol/kg was administered systemically as a single intravenous bolus injection to fasted pentobarbital anesthetized adult male Wistar rats. Up to 50 min after administration, blood samples were taken to measure glucose and insulin concentrations, both in the portal and in the systemic circulation. The effect of obestatin was evaluated in fasted and in glucose-stimulated conditions (IVGTT) and compared to control groups treated with saline or IVGTT, respectively. Intravenous administration of obestatin did not have any effect on glucose and insulin concentrations, neither systemic nor portal, when compared to the control groups. Only the glucose peak 1 min after administration of IVGTT was slightly higher in the obestatin treated rats: 605.8 ± 106.3% vs. 522.2 ± 47.1% in the portal circulation, respectively (NS), and 800.7 ± 78.7% vs. 549.6 ± 37.0% in the systemic circulation, respectively (P < 0.02), but it can be debated whether this has any clinical relevance. In the present study, we demonstrated that intravenously administered obestatin does not influence glucose and insulin concentrations, neither in the portal nor in the systemic circulation.     

Plasma obestatin is lower at fasting and not suppressed by insulin in insulin-resistant humans

Obestatin, a recently discovered 23-amino acid peptide, is involved in the regulation of appetite and body weight in antagonistic fashion to ghrelin, both deriving from a common precursor peptide. Ghrelin was shown to be associated with insulin resistance, which may also affect obestatin. We investigated the association between insulin resistance and plasma concentrations of obestatin and ghrelin in nondiabetic individuals with high (IS; n = 18, 13 females and 5 males, age 47 +/- 2 yr, BMI = 25.5 +/- 0.9 kg/m(2)) and low (IR; n = 18, 12 females and 6 males, age 45 +/- 2 yr, P = 0.49, BMI = 27.5 +/- 1.1 kg/m(2), P = 0.17) insulin-stimulated glucose disposal (M), measured by 2-h hyperinsulinemic (40 mU.min(-1).m(-2)) isoglycemic clamp tests. M(100-120 min) was higher in IS (10.7 +/- 0.7) than in IR (4.4 +/- 0.2 mg.min(-1).kg(-1), P < 10(-9)), whereas insulin-dependent suppression of free fatty acids (FFA) in plasma was reduced in IR (71 +/- 6% vs. IS: 82 +/- 5%, P < 0.02). In both groups, plasma ghrelin concentrations were comparable at fasting and similarly reduced by 24-28% during insulin infusion. IR had lower fasting plasma obestatin levels (383 +/- 26 pg/ml vs. IS: 469 +/- 23 pg/ml, P < 0.02). Clamp insulin infusion reduced plasma obestatin to approximately 81% of basal values in IS (P < 0.00002), but not in IR. Fasting plasma obestatin was correlated positively with M (r = 0.34, P = 0.04), HDL cholesterol (r = 0.45, P = 0.01), and plasma ghrelin concentrations (r = 0.80, P < 0.000001) and negatively with measures of adiposity, plasma FFA during clamp (r = -0.42, P < 0.01), and systolic blood pressure (r = -0.33, P < 0.05). In conclusion, fasting plasma concentrations of obestatin, but not of ghrelin, are reduced in insulin resistance and are positively associated with whole body insulin sensitivity in nondiabetic humans. Furthermore, plasma obestatin is reduced by insulin in insulin-sensitive but not in insulin-resistant persons.     

Ghrelin and obestatin can promote human ovarian granulosa cell functions and FSH effects

The aim of the present in-vitro experiments was to examine the direct influence of ghrelin and obestatin on viability, proliferation and progesterone release by human ovarian granulosa cells and their response to FSH administration. Human granulosa cells were cultured in presence of ghrelin or obestatin (both at 0, 1, 10 or 100 ng/ml) alone or in the presence of FSH (10 ng/ml). Cell viability, accumulation of proliferation markers PCNA and cyclin B1 and release of progesterone were analyzed by Trypan blue extrusion test, quantitative immunocytochemistry and ELISA. Ghrelin, obestatin and FSH up-regulated all the measured ovarian cell parameters. Moreover, both ghrelin and obestatin promoted all the stimulatory effects of FSH. The obtained results demonstrate the direct stimulatory action of ghrelin, obestatin and FSH on basic ovarian cell functions, as well as the ability of metabolic hormones to improve FSH action on human ovarian cells.     

Characteristics Associated With Fasting Appetite Hormones (Obestatin,Ghrelin, and Leptin)

Obestatin, derived from the same gene as the hunger hormone ghrelin, may reduce food intake in animals. The role of obestatin in human physiology is unclear. We evaluated cross‐sectional associations between participant characteristics and fasting levels of obestatin as well two other hormones associated with energy balance, ghrelin and leptin. Data are from the baseline visit of the Optimal Macronutrient Intake Trial to Prevent Heart Disease (OMNI‐Heart) Trial that enrolled adults with elevated blood pressure (systolic 120–159 mm Hg or a diastolic of 80–99 mm Hg) but who were otherwise healthy. Partial Spearman's correlations and linear regression models estimated the association between age, gender, BMI, physical activity, and smoking with fasting hormones. Obestatin was directly associated with ghrelin (r = 0.45, P < 0.05). On average, overweight (BMI 25–30) and obese (BMI > 30) individuals had obestatin concentrations that were 12.6 (s.d. 8.8) and 25.4 (s.d. 8.4) pg/ml lower compared to normal weight (BMI < 25) individuals, respectively (P for trend = 0.002). Overweight (BMI 25–30) and obese (BMI > 30) individuals had ghrelin concentrations that were 161.7 (s.d. 69.6) and 284.7 (s.d. 66.5) pg/ml lower compared to normal weight (BMI < 25) individuals, respectively (P for trend <0.0001). A 5 unit increase in BMI was associated with 41.3% (s.d. 4.3%) (P < 0.0001) higher leptin. Obestatin and ghrelin are directly correlated and share the same patterns of association with participant characteristics. Modifiable risk factors for chronic diseases, such as BMI, are associated with fasting levels of leptin, obestatin, and ghrelin.     

Circulating monocyte chemoattractant protein-1 in women with gestational diabetes

Monocyte chemoattractant protein 1 (MCP-1) has been implicated as a key factor in the recruitment and activation of peripheral blood leukocytes in atherosclerotic lesions and adipose tissue. Elevated levels of circulating MCP-1 have been found in patients with type 1 and type 2 diabetes, as well as with coronary artery disease. In this study we compared serum MCP-1 concentrations between pregnant women with normal glucose tolerance (NGT), gestational diabetes mellitus (GDM) and non-pregnant healthy women. The group studied consisted of 62 patients with GDM (mean age 30.1 +/- 5.0 years) at 29.0 +/- 3.5 week of gestation, 64 pregnant women with NGT (mean age 30.0 +/- 4.7 years) at 29.2 +/- 2.9 week of gestation and 34 non-pregnant healthy women (mean age 29.8 +/- 4.7 years). Serum MCP-1 concentration was measured using an enzyme - linked immunosorbent assay. Median MCP-1 concentrations did not differ significantly between women with GDM (median 342.3 [interquartile range 267.9-424.4] pg/ml) and NGT (338.0 [274.7-408.2] pg/ml), but were markedly lower than those found in non-pregnant women (485.2 [409.6-642.4] pg/ml, p<0.0001). After adjusting for glucose, the difference between pregnant and non-pregnant women remained highly significant (p<0.0001). In GDM patients MCP-1 levels correlated significantly with fasting glucose (r=0.2665, p=0.0363), insulin (r=0.4330, p=0.0004), HOMA-IR (r=0.4402, p=0.0003), ISQUICKI (r=-0.4402, p=0.0003), HbA1c (r=0.2724, p=0.0322), as well as with prepregnancy and current BMI (r=0.3501, p=0.0057 and r=0.3250, p=0.0106, respectively). Multiple regression analysis revealed that MCP1 concentrations were significantly predicted only by plasma glucose ( beta=0.3489, p=0.00004). Our results suggest that MCP1 levels are decreased in pregnant women, irrespective of their glucose tolerance status.     

Circulating obestatin is increased in patients with cardiorenal syndrome and positively correlated with vasopressin

Obestatin regulates fluid and electrolyte homeostasis mainly by opposing the action of vasopressin (AVP). We measured plasma concentration of obestatin and AVP in patients with cardiorenal syndrome (CRS). Plasma AVP and obestatin concentration were measured in 34 patients with type II CRS. The data were compared to that in 31 patients with chronic kidney disease (CKD), 41 patients with chronic heart failure (CHF) and 30 healthy subjects. Obestatin was significantly higher in the patients with CRS (355.8 ± 85.1 pg/ml) than that in the healthy controls (212.3 ± 37.9 pg/ml, P < 0.01), the patients with CKD (246.7 ± 34.3 pg/ml, P < 0.01) and the patients with CHF (258.4 ± 112.1 pg/ml, P < 0.01). AVP was also significantly higher in the patients with CRS (65.1 ± 36.0 pg/ml) than that in the healthy controls (38.5 ± 20.1 pg/ml, P < 0.01), the patients with CKD (50.4 ± 24.8 pg/ml, P < 0.01) and the patients with CHF (54.6 ± 16.3 pg/ml, P < 0.01). Plasma concentration of obestatin was positively correlated with AVP plasma concentration in the overall analysis that included subjects from all disease categories (r = 0.219, P < 0.05), but not within the CRS group. Plasma obestatin and vasopressin were elevated in patients with CRS. Plasma obestatin concentration seemed to be positively correlated with plasma AVP.     

Modulation of prostaglandin of the renal vascular action of arginne vasopressin

To determine whether the renal vascular effect of arginine vasopressin (AVP) is modulated by renal prostaglandin E₂ (PGE₂) were determined during the infusion of AVP in dogs during control conditions and after the administration of the inhibitor of prostaglandin synthesis, indomethacin. During control conditions, intrarenal administration for 10 min of a dose of AVP calculated to increase arterial renal plasma AVP concentration by 75 pg/ml produced a slight renal vasodilation (p<0.01) and an increase in renal venous plasma concentration of PGE₂. Renal venous PGE₂ concentration during control and AVP infusion averaged 33 ± 7 and 52 ± 12 pg/ml (p<0.05), respectively. After administration of indomethacin, the same dose of AVP induced renal vasoconstriction (p<0.05) and failed to enhance renal venous PGE₂ concentration (9 ± 1 to 8 ± 1 pg/ml). Intrarenal administration of 20 ng/kg. min of AVP for 10 min induced a marked renal vasoconstriction (p<0.01) and increased renal venous plasma PGE₂. Renal venous PGE₂ during control and AVP infusion averaged 31 ± 10 and 121 ± 31 pg/ml (p<0.01), respectively. Administration of the same dose of AVP following indomethacin produced a significantly greater and longer lasting renal vasoconstriction (p<0.01) and failed to increase renal venous plasma PGE₂ (10 ± 1 to 9 ± 1 pg/ml). These results indicate that a concentration of AVP comparable to that observed in several pathophysiological conditions induces a slight renal vasodilation which is mediated by renal prostaglandins. The results also indicate that higher doses of AVP induce renal vasoconstriction and that prostaglandin synthesis induced by AVP attenautes the renal vasoconstriction produced by this peptide.     

Obestatin and ghrelin in obese and in pregnant women

We identified, through qPCR, receptor mRNA for a number of gut peptides in female human omental fat: the incretins, GIP and GLP-1, the orexigenic peptides PYY-Y1 and -Y2 and ghrelin, and the anorexigenic peptide obestatin. Four cohorts of women were examined: lean controls (BMI<23), obese (BMI>41), obese diabetic and term pregnant women. Human fat expressed receptor mRNAs for all six peptides. Pregnant women expressed roughly three times as much orphan GPR-39 receptor, a proposed obestatin receptor, than other women and less than half as much of the ghrelin receptor (GHSR-1a). An immunoblot probed with a GPR-39 selective antibody yielded a single band corresponding to the correct molecular weight (52 kDa) for the proposed obestatin receptor. Fluorescent immunohistochemistry of human fat employing the same antibody indicated the receptor protein was localized to the adipocyte cell membrane. The concentration of obestatin circulating in blood was measured in the same cohort of women and was significantly lower in obese and obese diabetic women compared to control.     

Ghrelin is present in human colostrum, transitional and mature milk

Ghrelin and its mRNA have recently been found in numerous human tissues including breast. The aim of this study was to compare the ghrelin levels in colostrum, mature and transitional milk and plasma in lactating women with plasma samples from non-lactating women. Venous blood samples were obtained from 17 healthy lactating women aged 22-35 years and from 16 age-matched controls. Colostrum, transitional and mature milk samples were collected just before suckling. The level of bioactive ghrelin was determined by RIA. Comparison of ghrelin values for lactating women showed significantly lower concentrations in colostrum (70.3 +/- 18 pg/ml), transitional milk (83.8 +/- 18pg/ml) and mature milk (97.3 +/- 13 pg/ml) than in the corresponding plasma samples (first day 95 +/- 16 pg/ml, 10th day 111 +/- 13 pg/ml and 15th day 135 +/- 16 pg/ml). The plasma concentrations were lower in the lactating than in the non-lactating women. Thus, the ghrelin levels in colostrum, transitional and mature milk were elavated concomitantly with increasing plasma ghrelin after delivery. The origin of milk ghrelin is not known, but it probably comes from the plasma.     

EFFECT OF EXERCISE ON APPETITE-REGULATING HORMONES IN OVERWEIGHT WOMEN

Over the past decade, our knowledge of how homeostatic systems regulate food intake and body weight has increased with the discovery of circulating peptides such as leptin, acyl ghrelin, des-acyl ghrelin and obestatin. These hormones regulate the appetite and food intake by sending signals to the brain regarding the body''s nutritional status. The purpose of this study was to investigate the response of appetite-regulating hormones to exercise. Nine overweight women undertook two 2 h trials in a randomized crossover design. In the exercise trial, subjects ran for 60 min at 50% of maximal oxygen uptake followed by a 60 min rest period. In the control trial, subjects rested for 2 h. Obestatin, acyl ghrelin, des-acyl ghrelin and leptin concentrations were measured at baseline and at 20, 40, 60, 90 and 120 min after baseline. A two-way ANOVA revealed a significant (P < 0.05) interaction effect for leptin and acyl ghrelin. However, changes in obestatin and des-acyl ghrelin concentration were statistically insignificant (P > 0.05). The data indicated that although acute treadmill exercise resulted in a significant change in acyl ghrelin and leptin levels, it had no effect on plasma obestatin and des-acyl ghrelin levels.     

Surgery increases fetal plasma prostacyclin

Pulmonary arterial prostacyclin (as 6-keto-PGF_1α) concentrations of near term, fetakl lambs and goats were determined following fetal surgery and 24, 48, and 72 hrs later. Blood gases, pH, and arterial pressure were determined also. At the end of 2.5 hrs of surgery including exteriorization of the uterus and fetal thorocotomy, pulmonary arterial concentrations of 6-keto-PGF_1α was 948 ± 92 (SEM) pg/ml of blood. Twenty-four hrs later it had fallen to 435 ± 92 pg/ml and remained constant for the duration of monitoring. Maternal arterial 6-keto-PGF_1α concentration was much lower (105 ± 20 pg/ml of blood). No significance changes in fetal Pa_O2, Pa_CO2, pH, or arterial pressure were observed, although Pa_CO2 appeared to be elevated and pH reduced following surgery. These values normalized within 24 hrs. We conclude that surgical perturbation increases fetal arterial prostacyclin concentration. Increased prostacyclin levels are transient, reaching stable values within 24 hrs following completion of extensive surgery.     

The effect of weight reduction on plasma concentrations of ghrelin and insulin-like growth factor 1 in obese women

Introduction: The aim of the present study was to examine how weight loss treatment modulates plasma concentrations of ghrelin and insulin-like growth factor 1 (IGF-1) in obese women and to determine whether there is any association with possible changes in plasma concentrations of these hormones after weight loss. Material and methods: The study group consisted of 22 obese women without additional disease (age 40.6 +/- 12.9 years; BMI 37.2 +/- 4.6 kg/m(2)). All subjects participated in a 3-month weight reduction program. The measurements were performed at baseline and after weight loss. Plasma concentration of ghrelin and IGF-1 were measured by enzyme - linked immunosorbent assay (ELISA) kit. Serum concentrations of insulin were measured by radioimmunoassay (RIA). Body composition was determined by bioelectrical impedance analysis using a Bodystat analyser. Results: The mean weight loss was 9.3 +/- 4.1 kg (9.7 +/- 4.3%). Following weight loss, plasma ghrelin and IGF-1 concentrations increased significantly (63.5 +/- 13.0 vs. 72.8 +/- 15.1 pg/ml; p < 0.01; 126.9 +/- 67.0 vs. 170.5 +/- 83.3 ng/ml p < 0.01, respectively) and serum insulin concentrations decreased significantly (17.5 +/- 8.5 vs. 14.8 +/- 10.4 mIU/ml p< 0.05). We observed a significant positive correlation between the increase of ghrelin and decrease of body fat percentage after weight loss (r = 0.44, p = 0.03). There are no correlations between change of ghrelin and IGF-1concentrations and between changes of insulin and IGF 1 concentrations. Conclusion: Plasma concentrations of ghrelin and IGF-1 increased after weight loss. However, it seems there is no association between serum concentrations of ghrelin and IGF-1 in obese women.     

Relationship between elevated lipid peroxides,vitamin E deficiency and hypertension in preeclampsia

Preeclampsia or pregnancy-induced hypertension is a major cause of both maternal and fetal-neonatal morbidity and mortality. The deficiency of vitamin E can cause accumulation of lipid peroxidation products, which, in turn, can induce vasoconstriction. This study has examined any evidence of increased cellular lipid peroxidation and accumulation of malonydialdehyde (MDA, an end product of lipid peroxidation) in pregnancy-induced hypertension and any relationship between the elevated MDA and lower vitamin E levels with hypertension in pregnant women. EDTA-Blood was collected from pregnant women at the time of delivery. Plasma vitamin E was determined by HPLC; MDA by the thiobarbituric acid-reactivity. Subjects with diastolic blood pressure(DBP) 90 mm Hg were considered hypertensive (HT) and with <90 mm Hg normotensive (NT). Data (Mean±SE) from 49 NT and 11 HT women show that HT has significantly lower vitamin E (22±1 vs 27±1 nmole/ml, p<0.03) and elevated MDA levels (0.56±0.06 vs 0.43±0.02 nmole/ml, p<0.03) compared to NT; the ages and gestational ages of women were similar. Among all women, there was a significant positive relationship between DBP and MDA levels (r=0.27, p<0.05), and a significant negative relationship between vitamin E levels and DBP (–0.36, p<0.005), and a significant negative relationship between MDA and vitamin E levels (r=–0.27, p<0.05). Thus, HT women's plasma has significantly lower E and higher MDA levels, and DBP significantly correlates with the extent of vitamin E deficiency and increased MDA levels. This study suggests a relationship between elevated lipid peroxidation and lower vitamin E levels and hypertension in pregnancy (preeclampsia).     

Day-to-day variation in plasma interleukin-6 concentrations in older adults

Interleukin-6 (IL-6) is a pro-inflammatory cytokine commonly used in studies as a means of assessing chronic inflammatory status. Despite the use of plasma IL-6 as a marker of chronic inflammation few studies exist that examine the variability of plasma IL-6 within and between individuals. The purpose of this study was to assess inter- and intra-variability of plasma IL-6 concentration in men and postmenopausal women. Sixteen healthy postmenopausal women and 5 men completed the 2-week study. Fasted venous blood samples were obtained on three consecutive mornings for two consecutive weeks (six blood draws per participant). Mean plasma IL-6 values were 2.00 ± 1.74 pg/mL. Intra-variability was not significantly different (p > 0.05) however inter-variability was significantly different (p < 0.05). The index of individuality (II) was 0.20 and the standard error of the mean (SEM) was determined to equal 0.16 pg/mL (0.32 pg/mL; 1.96 SEM). An II of 0.20 demonstrates the need to carefully evaluate changes in plasma IL-6 concentration instead of utilizing population-based reference norms. In an older adult population until plasma IL-6 differences exceed 0.32 pg/mL such values could be considered normal fluctuation between trials and most likely not attributable to a nutrition intervention.     

Critical considerations in teh development of an assay for sulfidopeptide leukotrienes in plasma

A sensitive and specific assay has been developed for measurement of total sulfidopeptide leukotriense (LT) in plasma. LTC₄ and LTD₄ in plasma are converted to LTE₄ which is then extracted by C₁₈ Sep-Pak binding and elution. Total LTE₄ in resolved by reverse phase high performance liquid chromatography (RP-HPLC) and quantitated by radioimmunoassay (RIA). A [³H]LTE₄ internal standard is added to the starting plasma sample to allow RP-HPLC to be assayed for LTE₄-like immunoreactivity. The correlation between the measured increase in LTE₄ concentration after addition of incremental amounts of LTC₄ and LTE₄ to plasma was 0.989 and 0.978, respectively, with slopes of 1.05 and 1.11. Addition of 51 pg/ml LTE₄ to 5 ml plasma was detectable; the measured increase was 48 ± 12 pg/ml (mean ± SE, n = 7). The intra-assay coefficient of variation for 341 pg/ml of added LTC₄ was 3.2% (n = 6). Sulfidopeptide leukotrienes could not be detected in blood samples taken from 12 normal volunteers in whom the theoretical detection limit, calculated from the sensitivity of the RIA, the overall recovery of LTE₄, and the volume of plasma extracted, was 83 ± 4 pg LTE₄/ml plasma (0.19 ± 0.01 pmol sulfidopeptide leukotriene/ml plasma; mean ± SE).     

Circulating oestrogen concentrations during pregnancy in the African elephant (Loxodonta africana)

Oestrone, oestradiol-17 beta and oestriol were measured in plasma samples from non-pregnant and pregnant African elephants shot in the wild. Enzymic hydrolysis of plasma showed that approximately 90 and 96% of the total (i.e. conjugated plus unconjugated) concentrations of oestrone and oestradiol-17 beta, respectively were represented by conjugated hormones. Unconjugated oestrogens remained low (less than 50 pg ml) in all samples, with no distinction between non-pregnant and pregnant animals. Levels of total oestrone during pregnancy varied between 160 and 594 pg/ml but were not significantly different from non-pregnant values. Total oestradiol-17 beta concentrations were significantly elevated during pregnancy (P less than 0 X 01) and, despite considerable individual variation (193-1428 pg/ml), were consistently higher than non-pregnant values after 6 months of gestation. The elevated levels of oestradiol-17 beta resulted in a reversal of the total oestradiol-17 beta: oestrone concentration ratio at about 6 months of pregnancy. Concentrations of total oestriol did not exceed 103 pg/ml. An indirect method of measurement indicated that oestradiol-17 beta sulphate was probably the most abundant circulating oestrogen during pregnancy in the African elephant.