Increase in daily LH secretion in response to short-term calorie restriction in obese women with PCOS

We hypothesized that short-term calorie restriction would blunt luteinizing hormone (LH) hypersecretion in obese women with polycystic ovary syndrome (PCOS) and thereby ameliorate the anovulatory endocrine milieu. To test this hypothesis, 15 obese patients with PCOS and nine age- and body mass index-matched healthy women underwent 24-h blood sampling to quantitate plasma LH, leptin, and insulin levels. PCOS subjects were prescribed a very low caloric liquid diet (4.2 MJ/day) for 7 days and were then resampled. Basal and pulsatile LH secretion was threefold higher in PCOS subjects, but plasma insulin and leptin levels were not different in the calorie-replete state. Contrary to expectation, calorie restriction enhanced basal and pulsatile LH secretion even further. As expected, plasma glucose, insulin, and leptin concentrations decreased by 18, 75, and 50%, respectively. Serum total testosterone concentration fell by 23%, whereas serum estrone, estradiol, sex hormone-binding globulin (SHBG), and androstenedione concentrations remained unchanged. Enhanced LH secretion in the presence of normal metabolic and hormonal adaptations to calorie restriction points to anomalous feedback control of pituitary LH release in PCOS.

Inflammation and stroke: the Leiden 85-Plus Study

BACKGROUND

Experimental evidence indicates that interleukin-10 (IL-10) deficiency is associated with the development of cardiovascular and cerebrovascular disease. We analyzed the relation between low IL-10 production levels, history of stroke, and incident fatal stroke.

SUMMARY OF REPORT

All 85-year-old inhabitants of Leiden, Netherlands (n=599) were visited at their place of residence (response rate, 87%). Production levels of the anti-inflammatory cytokine IL-10 were assessed in a whole blood assay whereby lipopolysaccharide was used as a stimulus. Plasma concentrations of C-reactive protein (CRP) were also used as a marker of inflammation. A history of stroke was obtained at baseline (prevalence, 10%). The number of fatal strokes was prospectively obtained for a median follow-up of 2.6 years (incidence, 1.82 per 100 person-years at risk). Subjects with a history of stroke had significantly lower median IL-10 production levels at baseline than subjects without stroke (558 versus 764 pg/mL; P<0.05). They also had significantly higher median CRP concentrations (6 versus 3 mg/L; P<0.05). The odds ratio for a history of stroke increased to 2.30 (95% CI, 1.12 to 4.72) over strata representing decreasing production levels of IL-10. The relative risk for incident fatal stroke was 2.94 (95% CI, 1.01 to 8.53) when we compared subjects with low or intermediate baseline IL-10 production levels to those with high production levels of IL-10.

CONCLUSIONS

Our data support the hypothesis that subjects with low IL-10 production levels have an increased risk of stroke.

Reduction of plasma leptin levels and loss of its circadian rhythmicity in hypocretin (orexin)-deficient narcoleptic humans

Recent observations have implicated hypocretin deficiency in the pathogenesis of narcolepsy. Hypocretin neurotransmission also affects energy balance, and narcoleptic patients tend to become obese. Because hypocretins appear to have important neuroendocrine effects, we hypothesized that the neuroendocrine systems that regulate energy balance might be distinctly set in narcolepsy. As leptin is a pivotal part of these systems, we explored the 24-h plasma leptin (20-min sampling interval) concentration profile in six narcoleptic males and six normal controls, matched for age, sex, body mass index, waist/hip ratio, and fat mass. We thus demonstrated a reduction of the mean 24-h leptin concentration in narcoleptics to 52% of that in controls (5.9 microg/liter in narcolepsy vs. 11.4 microg/liter in controls; P < 0.05). Further, a nocturnal acrophase (clock time of the highest concentration), which is typical of normal leptin secretion, was observed in controls (mean, 2335 h; 95% confidence interval, 2105-0205 h), but not in narcoleptic patients. The mechanisms that potentially disturb the circadian rhythm of leptin levels in hypocretin-deficient narcoleptic humans include anomalies of the sleep-wake cycle and/or disruption of the circadian distribution of autonomic activity. As leptin deficiency clearly leads to morbid obesity in experimental animals and humans, we infer that the observed reduction of plasma leptin levels may predispose narcoleptic humans to weight gain.

No effect of preoperative selective gut decontamination on endotoxemia and cytokine activation during cardiopulmonary bypass: a randomized, placebo-controlled study

BACKGROUND

Cardiopulmonary bypass predisposes the splanchnic region to inadequate perfusion and increases in gut permeability. Related to these changes, circulating endotoxin has been shown to rise during cardiac surgery, and may contribute to cytokine activation, high oxygen consumption, and fever ("postperfusion syndrome"). To a large extent, free endotoxin in the gut is a product of the proliferation of aerobic gram-negative bacteria and may be reduced by nonabsorbable antibiotics.

OBJECTIVE

To evaluate the effect of preoperative selective gut decontamination (SGD) on the incidence of endotoxemia and cytokine activation in patients undergoing open heart surgery.

DESIGN

Prospective, randomized, placebo-controlled double-blind trial.

SETTING

Tertiary-care university teaching hospital.

INTERVENTION

Preoperative administration for 5 to 7 days of oral nonabsorbable antibiotics (polymyxin B and neomycin) vs. placebo. The efficacy of SGD was assessed by culture of rectal swabs.

PATIENTS

Forty-four patients (median age 65 yrs, 29 males) were included in a pilot study to establish the sampling points of perioperative measurements. Seventy-eight consecutive patients (median age 65 yrs, 55 males) were enrolled for the prospective study; of these, 51 were randomly allocated to take SGD (n = 24) or placebo (n = 27); 27 were included in a control group (no medication).

MEASUREMENTS AND RESULTS

SGD but not placebo effectively reduced the number of rectal swabs that grew aerobic gram-negative bacteria (27% vs. 93%, respectively; p < .001). SGD did not affect the occurrence of perioperative endotoxemia, nor did it reduce the tumor necrosis factor-alpha, interleukin-10, or interleukin-6 concentrations (p > .20), as determined before surgery, upon aorta declamping, 30 mins into reperfusion, or 2 hrs after surgery. Also, SGD did not alter the incidence of postoperative fever or clinical outcome measures such as duration of artificial ventilation and intensive care unit and hospital stay.

CONCLUSION

SGD effectively reduces the aerobic gram-negative bowel flora in cardiac surgery patients but fails to affect the incidence of perioperative endotoxemia and cytokine activation during cardiopulmonary bypass and the occurrence of a postperfusion syndrome.

Altered neuroregulation of GH secretion in viscerally obese premenopausal women

We used deconvolution analysis of 24-h plasma GH concentration profiles (10- min sampling intervals) to appraise GH secretion rates and elimination kinetics in obese (body mass index, approximately 34 kg/m2) premenopausal women with large visceral fat area (LVFA; n = 8) vs. small visceral fat area (SVFA; n = 8) as determined by magnetic resonance imaging. The subjects were matched for body mass index, body fat percentage, and age. The impact of the loss of 50% of prestudy weight excess induced by caloric restriction was assessed as well. The results were compared with those obtained in normal weight control women (n = 8). LVFA subjects manifested markedly (4-fold) reduced mean plasma GH levels, which was brought about by jointly diminished basal and pulsatile GH secretion. Moreover, visceral obesity was associated with loss of regularity of GH release, as established by the approximate entropy statistic. In contrast, SVFA subjects produced normal daily amounts of GH and exhibited mean 24-h plasma GH concentrations that were similar to those in normal weight controls. GH half-life and distribution volume were not different among the study groups. Importantly, weight loss did not affect the daily GH secretion rate in LVFA women, so that their mean plasma GH concentration remained considerably reduced (approximately 50%) compared with controls (despite the loss of approximately 40% of visceral fat). Normal GH kinetics in SVFA women were not significantly influenced by weight reduction. Thus, GH neuroregulation appears to be particularly altered in obese women with a tendency to store fat in their visceral adipose depot. Because weight loss did not reverse GH secretion rate in viscerally obese women, we speculate that relative hyposomatotropism is a primary feature of these women, which could be involved in their tendency to preferentially store excess fat in visceral adipose tissue.

Opioid overdose in a patient using a fentanyl patch during treatment with a warming blanket

IMPLICATIONS

This case describes the narcotic overdose associated with the use of a fentanyl transdermal patch in a patient being rewarmed with an external warming blanket during surgery. The clinical manifestation and the presumed pharmacokinetic mechanism responsible for the fentanyl overdose are discussed.

Renal clearance of endogenous leptin in hypertensive humans with or without renal artery stenosis

In humans, the kidney is involved in leptin clearance from the body. The present study was performed to assess the renal extraction of leptin in hypertensive patients with or without renal artery stenosis. Sixty-five hypertensive subjects (39 males and 26 females) underwent catheterization of the renal artery and both renal veins with blood sampling for measuring leptin levels. Blood flow to both kidneys was measured by the xenon washout technique. From these data, renal leptin uptake and renal fractional extraction of leptin were calculated. Endogenous creatinine clearance ranged from 24 to 191 ml/min in the males and from 20 to 149 ml/min in the females. In 25 patients, radiological signs of renal artery stenosis were present. Total renal leptin uptake by both kidneys averaged 141 +/- 47 ng x min(-1) x 100 g(-1). No differences in leptin uptake were found between males and females or between patients with or without renal artery stenosis. The average renal extraction fraction of leptin was 6 +/- 2%. Renal leptin uptake and renal extraction fraction of leptin did not correlate with arterial leptin concentrations or with blood pressure, endogenous creatinine clearance, or the presence or absence of renal artery stenosis. In hypertensive patients with or without renal artery stenosis, the kidney removes only a small fraction of circulating leptin from the body within one passage. This fraction remains relatively constant despite wide variations in renal function or circulating leptin.

A randomized controlled trial of three years growth hormone and gonadotropin-releasing hormone agonist treatment in children with idiopathic short stature and intrauterine growth retardation

We assessed the effectiveness and safety of 3 yr combined GH and GnRH agonist (GnRHa) treatment in a randomized controlled study in children with idiopathic short stature (ISS) or intrauterine growth retardation (IUGR). Gonadal suppression, GH reserve, and adrenal development were assessed by hormone measurements in both treated children and controls during the study period. Thirty-six short children, 24 girls (16 ISS/8 IUGR) and 12 boys (8 ISS/4 IUGR), with a height SD score of -2 SD or less in early puberty (girls, B2-3; boys, G2-3), were randomly assigned to treatment (n = 18) with GH (genotropin 4 IU/m(2). day) and GnRHa (triptorelin, 3.75 mg/28 days) or no treatment (n = 18). At the start of the study mean (SD) age was 11.4 (0.56) or 12.2 (1.12) yr whereas bone age was 10.7 (0.87) or 10.9 (0.63) yrs in girls and boys, respectively. During 3 yr of study height SD score for chronological age did not change in both treated children and controls, whereas a decreased rate of bone maturation after treatment was observed [mean (SD) 0.55 (0.21) 'yr'/yr vs. 1.15 (0.37) 'yr'/yr in controls, P < 0.001, girls and boys together]. Height SD score for bone age and predicted adult height increased significantly after 3 yr of treatment; compared with controls the predicted adult height gain was 8.0 cm in girls and 10.4 cm in boys. Furthermore, the ratio between sitting height/height SD score decreased significantly in treated children, whereas body mass index was not influenced by treatment. Puberty was effectively arrested in the treated children, as was confirmed by physical examination and prepubertal testosterone and estradiol levels. GH-dependent hormones including serum insulin-like growth factor I and II, carboxy terminal propeptide of type I collagen, amino terminal propeptide of type III collagen, alkaline phosphatase, and osteocalcin were not different between treated children and controls during the study period. Thus, a GH dose of 4 IU/m(2) seems adequate for stabilization of the GH reserve and growth in these GnRHa-treated children. We conclude that 3 yr treatment with GnRHa was effective in suppressing pubertal development and skeletal maturation, whereas the addition of GH preserved growth velocity during treatment. This resulted in a considerable gain in predicted adult height, without demonstrable side effects. Final height results will provide the definite answer on the effectiveness of this combined treatment.

Cesarean section combined with splenectomy in a parturient with immune thrombocytopenic purpura

The case of a 25-year-old parturient with immune thrombocytopenic purpura is discussed. The patient was first seen at 20 weeks' gestation because of a history of thrombocytopenia after delivery of a child six years previously. The patient was not compliant with prednisone therapy or return follow-up visits; a combined cesarean section with splenectomy was planned for this patient. The report discusses the multidisciplinary management of this patient during her pregnancy and delivery.

Endothelin-1 plasma concentration increases in the early phase of pulmonary hypertension development during respiratory distress syndrome: a study in newborn lambs

OBJECTIVE

Elevated plasma concentrations of endothelin-1 (ET-1) have been reported with pulmonary hypertension during respiratory distress syndrome (RDS). However, the exact role of ET-1 in the development of pulmonary hypertension during RDS is unclear. The relative time-course of changes in ET-1 concentrations and pulmonary artery pressure (P(ap)) during RDS may give insight in the role of ET-1.

METHODS

ET-1 and P(ap) changes were studied in an experimental model of RDS, induced by lung lavages in seven newborn lambs. Five other lambs served as controls.

RESULTS

Lung lavages induced a twofold increase of mean P(ap) (from 15 to 34 mm Hg) that remained present throughout the 4-h study period. Along with the increased P(ap), ET-1 plasma concentration showed a significant increase 15 min after induction of RDS at all three sample locations (pulmonary artery 198%, aorta 181% and right atrium 195% compared to baseline). This increased concentration remained high at 1 and 4 h of RDS. In control animals, no significant changes in ET-1 concentrations were observed. Plotting ET-1 concentration values against mean P(ap), in RDS and control animals at all time points, a correlation was found between the severity of the pulmonary hypertension and ET-1 concentration.

CONCLUSION

This experimental model of RDS shows that ET-1 concentration increases concomitant with the development of pulmonary hypertension, from an early time point onward. More severe pulmonary hypertension is associated with higher ET-1 concentrations, but whether ET-1 is a marker or a mediator of pulmonary hypertension remains as yet unsettled.

Growth hormone (GH) secretion in patients with an inactivating defect of the GH-releasing hormone (GHRH) receptor is pulsatile: evidence for a role for non-GHRH inputs into the generation of GH pulses

GH secretion is regulated by the interaction of GHRH and somatostatin and is released in 10-20 pulses in each 24-h cycle. The exact roles in pulse generation played by somatostatin, GHRH, and the recently isolated GH-releasing peptide, Ghrelin, are not fully elucidated. To investigate the GHRH-mediated GH secretion in human, we investigated pulsatile, entropic, and 24-h rhythmic GH secretion in two young adults (male, 24 yr; female, 23 yr) from a Moroccan family with a novel inactivating defect of the GHRH receptor gene. Data were compared with values in age- and gender-matched controls. Plasma GH concentration were measured by a sensitive immunofluorometric assay, with a detection limit of 0.01 mU/L. All plasma GH concentrations in the female patient were measurable; in the male patient 30 of 145 samples were at or below the detection limit. GH secretion was pulsatile, with 21 and 23 secretory episodes/24 h in the male and female patients, respectively. The fraction of basal to total GH secretion was raised in both patients by 0.18 and 0.15, respectively. The total 24-h GH production rate was greatly diminished; in the male patient it was 6.9 mU/L (normal values for his age, 26--63 mU/L), and in the female patient it was 4.2 mU/L (normal values for her age, 96--390 mU/L). The nyctohemeral plasma GH rhythm was preserved (P < 0.001), with normal acrophases (0430 and 0218 h in the male and female, respectively). Approximate entropy was greatly elevated in both subjects (0.82 in the male and 1.17 in the female; upper normal values for age and gender, 0.24 and 0.59, respectively). Intravenous injection of 50 microg GHRH failed to increase the plasma GH concentration in both patients, but 100 microg GH-releasing peptide-2 elicited a definite increase (male patient, 0.13 to 1.74 mU/L; female patient, 0.29 to 0.87 mU/L). Both patients had a partial empty sella on magnetic resonance imaging scanning. In summary, the present studies in two patients with a profound loss of function mutation of the GHRH receptor favor the view that in the human the timing of GH pulses is primarily supervised by intermittent somatostatin withdrawal, and the amplitude of GH pulses is driven by GHRH. In addition, we infer that effectual GHRH input controls the GH cell mass and the orderliness of the secretory process.

Atrial natriuretic peptide infusion and nitric oxide inhalation in patients with acute respiratory distress syndrome

Aim:

To study the effects of infusion of atrial natriuretic peptide (ANP) versus the inhalation of nitric oxide (NO) in patients with an early acute respiratory distress syndrome (ARDS).

Methods:

Ten patients with severe ARDS were studied in a crossover study design, within 72 hours after starting mechanical ventilation. We studied the effects of ANP infusion (10 ng/kg/min for 1 hour) and of inhalation of NO (20 ppm for 1 hour) on hemodynamic and respiratory patient parameters, as well as the effects on plasma levels of ANP, guanosine 3',5'-cyclic monophosphate, nitrate and endothelin-1.

Results:

Despite an approximate 50% increase in mixed venous ANP plasma concentration (from 86 ± 21 to 123 ± 33 ng/l, P < 0.05) during ANP infusion, there were no changes in mean pulmonary artery pressure, pulmonary vascular resistance index, extravascular lung water index, or in pulmonary gas exchange. NO inhalation, in contrast, lowered mean pulmonary artery pressure (from 26 ± 1.9 to 23.9 ± 1.7 mmHg, P < 0.01), pulmonary vascular resistance index (from 314 ± 37 to 273 ± 32 dynes/cm⁵/m², P < 0.05) and central venous pressure (from 8.2 ± 1.2 to 7.3 ± 1.1 mmHg, P < 0.02). Furthermore, NO inhalation improved pulmonary gas exchange, reflected by a decrease in alveolar-arterial oxygen gradient (from 41.9 ± 3.9 to 40.4 ± 3.6 kPa, P < 0.05), a small increase in oxygenation (PaO₂/FiO₂ from 17.7 ± 1.4 to 19.7 ± 1.1 kPa, P = 0.07) and a small decrease in venous admixture (Q_s/Q_t from 35.7 ± 2.0 to 32.8 ± 2.7%, P = 0.11).

Conclusion:

This study shows that, in contrast to NO inhalation, infusion of ANP neither improves oxygenation nor attenuates pulmonary hypertension or pulmonary edema in patients with severe ARDS.

Bezafibrate reduces heart rate and blood pressure in patients with hypertriglyceridemia

OBJECTIVE

In hypertriglyceridemic patients, hypertension occurs frequently and may be associated with hyperinsulinemia and elevated plasma levels of free fatty acids (FFA). Besides the lipid-lowering effects, fibrates have been shown to reduce blood pressure in hypertensive patients. The present study was undertaken to investigate the effects of bezafibrate on hemodynamics in relation to insulin, FFA, sympathetic activity, renal sodium absorption, cyclic-GMP (cGMP) and endothelin-1 in hypertriglyceridemic patients.

SUBJECTS AND METHODS

Hypertriglyceridemic patients (17) were randomized to receive in a double-blind placebo-controlled study bezafibrate or placebo for 6 weeks. At the end of both treatment periods, blood pressure and heart rate were measured automatically. Plasma insulin, FFA, aldosterone, catecholamines, cGMP, endothelin-1 levels and 24 h urine catecholamines and sodium excretion were assessed.

RESULTS

Bezafibrate therapy decreased serum triglycerides (-65%, P < 0.001) and hemodynamic parameters: heart rate decreased from 69 to 66/min (P = 0.009), systolic blood pressure from 137 to 132 mmHg (P = 0.01), diastolic blood pressure from 81 to 79 mmHg (P = 0.07) and mean blood pressure from 102 to 99 mmHg (P = 0.06). Bezafibrate therapy reduced FFA and insulin (-55 and -57% respectively, both P < 0.001), while sympathetic activity and renal sodium absorption were not affected. cGMP increased (+17%, P = 0.008), whereas endothelin-1 levels tended to decrease upon bezafibrate therapy (-10%, P = 0.077)

CONCLUSION

Bezafibrate reduces heart rate, blood pressure, insulin and FFA in hypertriglyceridemic patients. The hemodynamic effects cannot be attributed to changes in sympathetic activity or renal sodium absorption. Instead, based on the increase in plasma cGMP levels, the bezafibrate-induced hemodynamic effects are most likely to be caused by bezafibrate-induced improvement of endothelial function.

Basal, pulsatile, entropic, and 24-hour rhythmic features of secondary hyperprolactinemia due to functional pituitary stalk disconnection mimic tumoral (primary) hyperprolactinemia

Under physiological conditions, PRL secretion is regulated precisely by various stimulating and inhibiting factors. Hyperprolactinemia may arise as a primary consequence of a PRL-secreting pituitary adenoma. Secondary hyperprolactinemia (SH) may emerge in patients with hypothalamic disease, hypophyseal stalk compression, or suprasellar extension of a (nonlactotrope) pituitary adenoma. The latter may reflect diminished delivery of dopamine or other inhibitory factors to normal lactotropes. We hypothesized that diurnal and ultradian rhythms of PRL secretion would differ in secondary (e.g. hypothalamic) and primary (e.g. tumoral states) hyperprolactinemia (PH), assuming that the underlying pathophysiologies differ. To test this clinical postulate, we investigated the patterns of 24-h PRL release in eight patients with SH associated with functional hypothalamo-pituitary disconnection and in eight patients with PH attributable to microprolactinoma. Data in each group were compared with values in healthy gender-matched controls. PRL time series were obtained by repetitive 10-min blood sampling, followed by high- precision immunofluorometric assay. PRL concentration profiles were analyzed by the complementary tools of model-free discrete peak detection, waveform-independent deconvolution analysis, cosinor regression, and the approximate entropy metric to quantitate pulsatile, basal, 24-h rhythmic, and pattern-dependent (entropic) PRL secretion. Patients with tumoral hyperprolactinemia (PH) showed a 2-fold higher 24-h mean serum PRL concentration than patients with SH (62 +/- 13 microg /L vs. 30 +/- 6.9 microg/L, respectively, P = 0.029). Estimated PRL pulse frequency (events/24 h) was similar in the two patient groups (18.5 +/- 0.7 vs. 17.6 +/- 0.8; P = 0.395) but elevated over that in euprolactinemic controls (P < 0.0001 for both). Deconvolution analysis disclosed a mean daily PRL secretion rate of 790 +/- 170 microg in PH patients vs. 380 +/- 85 microg in SH patients (P = 0.030). Nonpulsatile PRL secretion comprised nearly 70% of total secretion in both patient groups and 50% in controls (P < 0.0001). Cosinor analysis revealed similar acrophases in all three study cohorts. The mean skewness of the statistical distribution of the individual PRL sample secretory rates was reduced, compared with controls (P < 10 (-5) for each), but equivalent in SH and PH patients (0.83 +/- 0.12 vs. 0.78 +/- 0.08, respectively), denoting a loss of the normal spectrum of low- and higher-amplitude secretion rates. Approximate entropy, a regularity statistic, was markedly elevated in both patient groups over controls (P < 10 (-6) for each) and was slightly higher in PH patients than in SH patients (1.639 +/- 0.029 vs. 1.482 +/- 0.067, P = 0.048). In summary, patterns of PRL secretion in PH and SH states exhibit an equivalently increased frequency of PRL pulses, a comparably marked rise in nonpulsatile (basal) PRL secretion. Despite overlap, the regularity of PRL release patterns is disrupted even more profoundly in PH (tumoral), compared with SH. Assuming that the orderliness of serial PRL output monitors normal integration within a feedback-controlled neurohormone axis, then the more disorderly patterns of tumoral PRL secretion point to greater regulatory disruption in PH. The latter may reflect abnormal secretory behavior associated with lactotrope neoplastic transformation and/or isolation of the tumor cell mass from normal hypothalamic controls.

Hyperlipidaemia is associated with increased insulin-mediated glucose metabolism, reduced fatty acid metabolism and normal blood pressure in transgenic mice overexpressing human apolipoprotein C1

AIMS/HYPOTHESIS

Insulin resistance for glucose metabolism is associated with hyperlipidaemia and high blood pressure. In this study we investigated the effect of primary hyperlipidaemia on basal and insulin-mediated glucose and on non-esterified fatty acid (NEFA) metabolism and mean arterial pressure in hyperlipidaemic transgenic mice overexpressing apolipoprotein C1 (APOC1). Previous studies have shown that APOC1 transgenic mice develop hyperlipidaemia primarily because of an impaired hepatic uptake of very low density lipoprotein (VLDL).

METHODS

Basal and hyperinsulinaemic (6 mU.kg-1.min-1), euglycaemic (7 mmol/l) clamps with 3(-)3H-glucose or 9,10(-)3H-palmitic acid infusions and in situ freeze clamped tissue collection were carried out.

RESULTS

The APOC1 mice showed increased basal plasma cholesterol, triglyceride, NEFA and decreased glucose concentrations compared with wild-type mice (7.0 +/- 1.2 vs 1.6 +/- 0.1, 9.1 +/- 2.3 vs 0.6 +/- 0.1, 1.9 +/- 0.2 vs 0.9 +/- 0.1 and 7.0 +/- 1.0 vs 10.0 +/- 1.1 mmol/l, respectively, p < 0.05). Basal whole body glucose clearance was increased twofold in APOC1 mice compared with wild-type mice (18 +/- 2 vs 10 +/- 1 ml.kg-1.min-1, p < 0.05). Insulin-mediated whole body glucose uptake, glycolysis (generation of 3H2O) and glucose storage increased in APOC1 mice compared with wild-type mice (339 +/- 28 vs 200 +/- 11; 183 +/- 39 vs 128 +/- 17 and 156 +/- 44 vs 72 +/- 17 mumol.kg-1.min-1, p < 0.05, respectively), corresponding with a twofold to threefold increase in skeletal muscle glycogenesis and de novo lipogenesis from 3-(3)H-glucose in skeletal muscle and adipose tissue (p < 0.05). Basal whole body NEFA clearance was decreased threefold in APOC1 mice compared with wild-type mice (98 +/- 21 vs 314 +/- 88 ml.kg-1.min-1, p < 0.05). Insulin-mediated whole body NEFA uptake, NEFA oxidation (generation of 3H2O) and NEFA storage were lower in APOC1 mice than in wild-type mice (15 +/- 3 vs 33 +/- 6; 3 +/- 2 vs 11 +/- 4 and 12 +/- 2 vs 22 +/- 4 mumol.kg-1.min-1, p < 0.05) in the face of higher plasma NEFA concentrations (1.3 +/- 0.3 vs 0.5 +/- 0.1 mmol/l, p < 0.05), respectively. Mean arterial pressure and heart rate were similar in APOC1 vs wild-type mice (82 +/- 4 vs 85 +/- 3 mm Hg and 459 +/- 14 vs 484 +/- 11 beats.min-1).

CONCLUSIONS/INTERPRETATION

1) Hyperlipidaemic APOC1 mice show reduced NEFA and increased glucose metabolism under both basal and insulin-mediated conditions, suggesting an intrinsic defect in NEFA metabolism. Primary hyperlipidaemia alone in APOC1 mice does not lead to insulin resistance for glucose metabolism and high blood pressure.

Circulating atrial natriuretic peptide plasma levels as a marker for cardiac damage after radiotherapy

PURPOSE

To investigate whether plasma concentrations of atrial natriuretic peptide (ANP) could be used to identify patients with radiation mediated cardiac dysfunction.

MATERIALS AND METHODS

Circulating levels of ANP were measured in patients who have been irradiated on a large part of the heart (50-80%; Hodgkin's disease) or smaller part of the heart (20-30%; primary breast cancer). C-terminal ANP was determined by radioimmunoassay (RIA) using a commercial kit.

RESULTS

In this study ANP plasma levels of 121 patients (Hodgkin's disease, 73 patients; breast cancer, 48 patients) and 67 controls were examined. ANP plasma levels of both Hodgkin patients (28.8+/-2.2, P=0.003) and breast cancer patients (20.4+/-2.8 ng/l, P=0.01) were significantly elevated when compared to age-matched controls (13.5+/-1.2 ng/l). Both for the Hodgkin (R=0.42, P=0.05) and breast cancer group (R=0.50, P=0.09) a positive relation between ANP plasma values and age was found. However, no clear relation between ANP plasma levels and time post treatment could be demonstrated. Patients with clinical symptoms of cardiovascular disease (n=25) had significantly higher ANP plasma levels (P<0.001) compared to patients in the same treatment group without evidence of cardiac disease (50.2+/-7.5 vs. 23.3+/-1.3 ng/l, P<0.001, and 38.2+/-12.4 vs. 16.3+/-1.6 ng/l, P<0.001, for Hodgkin's disease and breast cancer, respectively). Eight patients suffered from essential hypertension (n=8), whereas the remaining group of 17 patients showed a variety of cardiac disorders (i.e. myocardial infarction, decreasing ventricular function, and atrial fibrillations). In 11 patients cardiac problems were manifest either before or within a few years after mediastinal therapy. In two patients treated for Hodgkin's disease, and in four patients treated for breast cancer cardiac problems became manifest a long time (>10 years) after radiotherapy. Probably in this group of patients cardiac problems are related to the therapy.

CONCLUSIONS

The present study indicates that ANP plasma levels could be used to identify patients with radiation induced cardiac dysfunction.

Effect of modified sham feeding and insulin-induced hypoglycemia on function of the proximal stomach

BACKGROUND/AIM

Animal experiments have shown that vagal cholinergic stimulation causes an increase in proximal gastric tone, but little is known about the effect of vagal stimulation on proximal gastric motor function in humans. Vagal cholinergic stimulation can be elicited by modified sham feeding (MSF) or by insulin-induced hypoglycemia. The aim of our study was to investigate the effect of MSF and insulin-induced hypoglycemia on the motor and sensory function of the proximal stomach in humans.

METHODS

Eight healthy volunteers participated in random order in three experiments: (A) control experiment, (B) MSF and (C) intravenous insulin injection. Intragastric volume was recorded with a barostat set at a constant preselected pressure level (MDP + 2 mm Hg). Pancreatic polypeptide (PP) secretion was measured as an indicator of cholinergic tone.

RESULTS

PP secretion increased significantly after both MSF (p<0.05) and insulin administration (p<0.01). No changes in intragastric volume were seen after MSF, while intragastric volume increased significantly in response to insulin-induced hypoglycemia when compared to control (290+/-43 vs. 148+/-24 ml; p<0.01). No differences in perception scores were seen between the three experiments.

CONCLUSIONS

Vagal cholinergic stimulation by MSF has no effect on the motor function of the proximal stomach, while insulin-induced hypoglycemia causes a relaxation of the proximal stomach.

Hyperleptinemia in women with Cushing's disease is driven by high-amplitude pulsatile, but orderly and eurhythmic, leptin secretion

The episodicity of 24 h leptin release was studied in seven women (mean age 39 years, range 22-56 years) with pituitary-dependent hypercortisolism and in seven age- and body mass index (BMI)-matched female controls. Pulsatile leptin release was quantified by model-free cluster analysis and deconvolution, the orderliness of leptin patterns by the approximate entropy statistic (ApEn), and nyctohemeral leptin rhythmicity by cosinor analysis. Blood samples were taken at 10 min intervals for 24 h. Both cluster and deconvolution analysis revealed 2.4-fold increased leptin secretion in patients, caused by combined and equal amplification of basal and pulsatile secretion. Cluster analysis identified 7.1+/-1.5 peaks per 24 h in patients and 6.0+/-0.5 in controls (not significant). The statistical distribution of the individual sample secretory rates was similarly skewed in patients and controls (0.55+/-0.12 vs 0.52+/-0.07). The acrophase (timing of the nyctohemeral leptin peak) in patients occurred at 2314 h (+/-76 min) and at 0058 h (+/-18 min) in controls (not significant). The approximate entropy of leptin release was equivalent in patients and controls (1.67+/-0.03 vs 1.61+/-0.05). The approximate entropy (ApEn) for cortisol in patients was 1.53+/-0.09 and in controls was 0.93+/-0.07 (P<0.0005). Cross-ApEn showed significant pattern synchrony between leptin and cortisol release, which (unexpectedly) was not disrupted by the cortisol excess (patients, 2.02+/-0.04; controls, 1.88+/-0.09; P=0.233). Insulin levels in fasting patients ('fasting insulin') were 27+/-5.7 mU/l vs 14+/-1.6 mU/l in controls (P=0.035). Leptin secretion correlated with fasting insulin levels (R(2)=0.34, P=0.028) and with the cortisol production rate (R(2)=0.33, P=0.033) when patients and controls were combined. In summary, Cushing's disease in women increases leptin production about twofold in an amplitude-specific way. The pulse-generating, nyctohemeral phase-determining, and entropy-control mechanisms that govern the 24 h leptin release are not altered. The increased secretion is not explained by BMI and is probably only partly explained by increased insulin production, suggesting a cortisol-dependent change in adipose leptin secretion.

Endotoxin, cytokines, and procalcitonin in febrile patients admitted to the hospital: identification of subjects at high risk of mortality

We prospectively examined 464 febrile patients (median age, 61 years) for predictors of in-hospital death, by use of univariate and multivariate logistic regression using clinical data (age, underlying disease, duration of fever, chills, and shock on admission) and plasma endotoxin, TNF-alpha, IL-6, IL-10, and procalcitonin levels. The mortality rate was 4.6-fold higher (95% confidence interval [CI], 1.8-12) in 31 patients with shock on admission, 7 of whom died; the strongest association with mortality was the endotoxin concentration (relative risk, 13.7; 95% CI, 1. 4-136), which predicted 5 of the deaths with a 5% false-positive rate. For 433 patients without shock on admission, mortality (26 deaths) was associated with age and underlying disease: clinical data predicted 30% of the deaths, whereas IL-6 and procalcitonin levels identified an extra 10% with a 5% false-positive rate. When febrile patients are screened on hospital admission to identify those with a high risk for mortality, clinical judgment on the basis of age, underlying disease, and recent history outweighs the predictive value of endotoxin, cytokine, and procalcitonin levels. Only in patients who present with shock will measurement of endotoxin levels help predict those who will likely die at the cost of few false-positive results.

Apparently complete restoration of normal daily adrenocorticotropin, cortisol, growth hormone, and prolactin secretory dynamics in adults with Cushing's disease after clinically successful transsphenoidal adenomectomy

ACTH production in Cushing's disease is characterized by a markedly elevated rate of basal (nonpulsatile) secretion, an increased mass of ACTH released per burst and an unremarkable pulse frequency. In addition, the ACTH secretory process and that of GH and PRL exhibit profoundly disordered patterns. Whether some or all of these disturbances can be reversed or normalized by transsphenoidal microadenomectomy remains unknown. We therefore investigated the detailed dynamics of ACTH, GH, and PRL in eight patients (aged 38.9+/-4.2 yr) with pituitary-dependent Cushing's disease who were in long-term (8.2+/-1.7 yr) clinical remission following transsphenoidal surgery and eight controls matched for age, gender, and body mass index. To this end, blood was sampled at 10-min intervals for 24 h for the later assay of ACTH, cortisol, GH, and PRL. Secretory activity was quantitated by deconvolution methods, and the pattern orderliness (regularity) of hormone release was determined by the approximate entropy (ApEn) statistic. The joint synchrony of ACTH and cortisol secretion was monitored by the cognate bivariate statistic, cross-ApEn. Diurnal properties of the hormonal release were appraised by cosinor analysis. Based on deconvolution analysis, postsurgical patients exhibited a normal frequency, half-life, duration, and mass of ACTH and cortisol secretory bursts. Accordingly, the 24-h production rates of both ACTH (2.5+/-0.7 microg/L in patients vs. 2.9+/-0.7 microg/L in controls; P = 0.755) and cortisol (49+/-11 micromol/L in patients vs. 73+/-15 micromol/L in controls; P = 0.217) were normal also. The acrophase of the diurnal rhythm of ACTH (patients, 0817 h +/- 37 min; controls, 0850 h +/- 38 min; P = 0.629) and cortisol (patients, 1000 h +/- 24 min; controls, 0855 h +/- 30 min; P = 0.175) was also restored by surgery. ApEn values of ACTH (patients, 1.168 +/- 0.090; controls, 0.864+/-0.122; P = 0.133) and cross-ApEn of ACTH-cortisol (patients, 1.396+/-0.087; controls, 1.170+/-0.076; P = 0.140) secretion were both normal in this cohort, denoting restoration of the secretory process regularity. Cortisol ApEn was slightly higher in patients (patients, 1.034+/-0.084; controls, 0.831+/-0.038; P = 0.048). Both GH and PRL time series manifested full reconstitution of pulsatile, 24-h rhythmic, and entropic properties. In summary, clinically successful transsphenoidal microadenomectomy in adults with Cushing's disease can fully normalize virtually all quantitative features of regulated ACTH, cortisol, GH, and PRL secretion. Further studies will be needed to establish the consistency of these findings in larger cohorts of adults with Cushing's disease and in children with this disorder and to delineate the significance, if any, of a residual, minimally detectable disruption of orderly cortisol secretion in this patient population.

Growth hormone and prolactin are secreted more irregularly in patients with Cushing's disease

OBJECTIVE

To investigate whether the spontaneous secretion of growth hormone and prolactin in adult patients with pituitary-dependent Cushing's disease is decreased.

PATIENTS

Fourteen adult patients (9 women, 5 men; age: 34 +/- 3.4 years, mean +/- SEM) with pituitary-dependent Cushing's disease and 14 controls matched for age, gender and body mass index were studied.

METHODS

Blood samples were withdrawn at 10 minutes intervals starting at 0900 h for 24 h. GH and PRL release were quantified with deconvolution methods. The regularity of GH and PRL release was measured with approximate entropy statistics.

RESULTS

The number of GH secretory events per 24 h was higher in patients than in controls: 19 +/- 1.3 vs. 14 +/- 1.5 peaks per 24 h, respectively (P = 0.020). GH secretion rate was about one quarter lower in patients (ns), and the 24 h secretion of PRL was unchanged. Total GH production correlated negatively with the urinary excretion of free cortisol (R = 0.729, P = 0.005) and with the plasma cortisol production rate (R = 0.613; P = 0.026). The orderliness of GH and PRL secretion was appraised with the approximate entropy statistic (ApEn). For GH secretion ApEn(1,20%) in patients was 0.952 +/- 0.084 vs. 0.404 +/- 0.047 in controls, P = 1.17 x 10-4, pointing to a markedly disordered secretion in patients. Similar results were obtained for PRL secretion: patients: 1.586 +/- 0.063 vs. 1.003 +/- 0.068 in controls, P = 3.67 x 10-5. No statistically significant differences in secretory dynamics were demonstrated between the 10 patients with a microadenoma and the four with a macroadenoma.

CONCLUSION

The amount of GH released spontaneously into the circulation in adult patients with pituitary-dependent Cushing's disease is inversely related to the degree of cortisol hypersecretion. However, except for severe hypercortisolism, GH secretion is relatively preserved. In addition, secretion of GH and PRL is remarkably disordered in patients with Cushing's disease. Since we could not detect differences in GH and/or PRL secretory dynamics between patients with a microadenoma and those harboring a macroadenoma, we speculate that an intrapituitary paracrine mechanism and/or elevated cortisol feedback effects may be responsible for the evident disruption of GH and PRL secretion patterns.

Insulin secretion and sensitivity after simultaneous pancreas-kidney transplantation estimated by continuous infusion of glucose with model assessment

BACKGROUND

Monitoring of insulin secretion and sensitivity after pancreas transplantation remains a practical problem.

METHODS

We introduced the simple structural model, continuous infusion of glucose with model assessment (CIGMA), to obtain insulin secretion and insulin sensitivity estimations after 35 successful simultaneous pancreas-kidney transplantations. Eighteen non-diabetic kidney transplant recipients were used as control group.

RESULTS

The baseline characteristics were equal between the two groups except for higher fasting insulin levels in the pancreas transplant group. After the 1-hr CIGMA glucose load, the pancreas transplant group reached a mean +/- SD blood glucose of 8.2+/-1.7 mmol/L compared with 7.3+/-1.0 mmol/L in the control group (P = 0.05). Concurrent stimulated insulin and C-peptide levels were 48+/-28 mU/L and 2.3+/-0.9 nmol/L in the pancreas transplant group compared with 36+/-21 mU/L and 2.9+/-1.1 nmol/L in the control group (P = 0.1 and P = 0.03, respectively). Both the CIGMA estimation for secretion as well as the CIGMA estimation for sensitivity were lower in pancreas transplant group (P = 0.003 and P = 0.01, respectively). Mean +/- SE coefficients of variation for the model estimations were 15+/-4% for secretion and 17+/-6% for sensitivity.

CONCLUSIONS

We conclude that CIGMA can be used clinically to evaluate carbohydrate metabolism in pancreas-kidney transplant recipients. These patients have a reduction in insulin secretory capacity and evidence of more insulin resistance than non-diabetic kidney transplant recipients.

C-reactive protein is a strong but nonspecific risk factor of fatal stroke in elderly persons

An elevated level of C-reactive protein is a strong predictor of cardiovascular events in elderly persons. Whether C-reactive protein has direct adverse vascular effects or is a marker of aspecific systemic inflammation remains to be determined. The aim of this study was to investigate the relation between C-reactive protein and the occurrence of fatal strokes in elderly persons. In the Leiden 85-Plus Study, a population-based prospective follow-up study, we studied the levels of C-reactive protein in 80 participants who died from stroke within the first 5 years of follow-up. Levels of C-reactive protein were determined in serum samples at baseline. Levels of C-reactive protein were also determined in 82 control subjects who survived for the first 5 years of follow-up and in 83 participants who died from noncardiovascular causes. Mortality risks were estimated with logistic regression and adjusted for differences in age, sex, smoking, medication, total cholesterol, history of diabetes or hypertension, and previous cardiovascular events. Levels of C-reactive protein at baseline were 2-fold higher in subjects who died from stroke than in control subjects (median 5.7 versus 2.7 mg/L, P<0.005). The levels of C-reactive protein in subjects who died from stroke or from noncardiovascular causes were similar (median 5.7 versus 4.9 mg/L, P=0.7). The risk of death from stroke as well as from noncardiovascular causes increased linearly up to 10-fold in subjects with the highest levels of C-reactive protein at baseline (P<0.001). The levels of C-reactive protein were lower when more time had elapsed between blood sampling and time of death during follow-up (P=0.01). C-reactive protein is a strong but nonspecific risk factor of fatal stroke in old persons. The data do not support the idea that C-reactive protein has direct vascular effects that underlie fatal cerebrovascular disease.