Measurement of polarization observables T, P, and H in π0 and η photoproduction off quasi-free nucleons

The target asymmetry T, recoil asymmetry P, and beam-target double polarization observable H were determined in exclusive π 0 and η photoproduction off quasi-free protons and, for the first time, off quasi-free neutrons. The experiment was performed at the electron stretcher accelerator ELSA in Bonn, Germany, with the Crystal Barrel/TAPS detector setup, using a linearly polarized photon beam and a transversely polarized deuterated butanol target. Effects from the Fermi motion of the nucleons within deuterium were removed by a full kinematic reconstruction of the final state invariant mass. A comparison of the data obtained on the proton and on the neutron provides new insight into the isospin structure of the electromagnetic excitation of the nucleon. Earlier measurements of polarization observables in the γ p → π 0 p and γ p → η p reactions are confirmed. The data obtained on the neutron are of particular relevance for clarifying the origin of the narrow structure in the η n system at W = 1.68 GeV . A comparison with recent partial wave analyses favors the interpretation of this structure as arising from interference of the S 11 ( 1535 ) and S 11 ( 1650 ) resonances within the S 11 -partial wave.

A Pragmatic Randomized Trial Comparing Surgical Clipping and Endovascular Treatment of Unruptured Intracranial Aneurysms

BACKGROUND AND PURPOSE

Surgical clipping and endovascular treatment are commonly used in patients with unruptured intracranial aneurysms. We compared the safety and efficacy of the 2 treatments in a randomized trial.

MATERIALS AND METHODS

Clipping or endovascular treatments were randomly allocated to patients with one or more 3- to 25-mm unruptured intracranial aneurysms judged treatable both ways by participating physicians. The study hypothesized that clipping would decrease the incidence of treatment failure from 13% to 4%, a composite primary outcome defined as failure of aneurysm occlusion, intracranial hemorrhage during follow-up, or residual aneurysms at 1 year, as adjudicated by a core lab. Safety outcomes included new neurologic deficits following treatment, hospitalization of >5 days, and overall morbidity and mortality (mRS > 2) at 1 year. There was no blinding.

RESULTS

Two hundred ninety-one patients were enrolled from 2010 to 2020 in 7 centers. The 1-year primary outcome, ascertainable in 290/291 (99%) patients, was reached in 13/142 (9%; 95% CI, 5%-15%) patients allocated to surgery and in 28/148 (19%; 95% CI, 13%-26%) patients allocated to endovascular treatments (relative risk: 2.07; 95% CI, 1.12-3.83; P = .021). Morbidity and mortality (mRS >2) at 1 year occurred in 3/143 and 3/148 (2%; 95% CI, 1%-6%) patients allocated to surgery and endovascular treatments, respectively. Neurologic deficits (32/143, 22%; 95% CI, 16%-30% versus 19/148, 12%; 95% CI, 8%-19%; relative risk: 1.74; 95% CI, 1.04-2.92; P = .04) and hospitalizations beyond 5 days (69/143, 48%; 95% CI, 40%-56% versus 12/148, 8%; 95% CI, 5%-14%; relative risk: 0.18; 95% CI, 0.11-0.31; P < .001) were more frequent after surgery.

CONCLUSIONS

Surgical clipping is more effective than endovascular treatment of unruptured intracranial aneurysms in terms of the frequency of the primary outcome of treatment failure. Results were mainly driven by angiographic results at 1 year.

Doctor-patient communication during the Corona crisis - web-based interactions and structured feedback from standardized patients at the University of Basel and the LMU Munich

Background: Due to the pandemic-related restrictions in classroom teaching at the medical faculties of the LMU Munich and the University of Basel, teaching methods with standardized patients (SPs), were shifted to a digital, web-based format at short notice as of April 2020. We report on our experiences with the WebEncounter program, which was used for the first time in German-speaking countries. The program enables one-to-one encounters between SPs and students. Students receive an invitational email with brief instructions and background information on the case. SPs use case-specific criteria that are compliant with the learning objectives for digital evaluation during the encounter. A feedback session takes place immediately following the encounter. The SPs address the didactically relevant sections and can illustrate them with the corresponding video sequences. Finally, the students receive the links to the video recordings of the encounter and the feedback unit by email. Project description: The aim of this pilot study was to analyze the practicability of the program and its acceptance by students and SPs. In addition, we examined whether the operationalization of the learning objectives in the form of assessment items has an impact on the content and thematic development of courses in the area of doctor-patient communication. Methods: To implement the program, patient cases previously tested in communication seminars in Munich and Basel were rewritten and case-specific evaluation criteria were developed. SPs were trained to use the program, to present their patient figure online and to give feedback. The experience of those involved (faculty, SPs and SP trainers, students) in implementing the program was documented at various levels. The frequency and causes of technical problems were described. Student results on the patient cases and on the feedback items were collected quantitatively and, where possible, supplemented by free-text statements. Results: Data from 218/220 students in Basel and 120/127 students in Munich were collected and evaluated. Students were very satisfied with the patient cases, the encounter with the SPs and their feedback: 3.81±0.42. SPs experienced the training as an increase in their competence and the structured feedback as particularly positive. The training effort per SP was between 2.5 and 4 hours. The results show predominantly normally-distributed, case-specific sum scores of the evaluation criteria. The analysis of the individual assessment items refers to learning objectives that students find difficult to achieve (e.g. explicitly structuring the conversation). Problems in the technical implementation (<10 percent of the encounters) were due mainly to the use of insufficient hardware or internet connection problems. The need to define case-specific evaluation criteria triggered a discussion in the group of study directors about learning objectives and their operationalization. Summary: Web-based encounters can be built into the ongoing communication curriculum with reasonable effort. Training the SPs and heeding the technical requirements are of central importance. Practicing the virtual consultation was evaluated very positively by the students - in particular, the immediate feedback in the protected dialogue was appreciated by all involved.

The challenge of post-mortem GHB analysis: storage conditions and specimen types are both important

BACKGROUND

For the interpretation of concentrations of gamma-hydroxybutyrate (GHB) in post-mortem specimens, a possible increase due to post-mortem generation in the body and in vitro has to be considered. The influence of different storage conditions and the specimen type was investigated.

METHOD AND MATERIAL

Post-mortem GHB concentrations in femoral venous blood (VB), heart blood (HB), serum (S) from VB, urine (U), cerebrospinal fluid (CSF) and vitreous humour (VH) were determined by gas chromatography-mass spectrometry after derivatisation. Various storage conditions, that is 4 °C or room temperature (RT) and the addition of sodium fluoride (NaF), were compared during storage up to 30 days. Additionally, bacterial colonisation was determined by mass spectrometry fingerprinting.

RESULTS

Twenty-six cases without involvement of exogenous GHB were examined. GHB concentrations (by specimen) at day 0 were 3.9-22.1 mg/L (VB), 6.6-33.3 mg/L (HB), < 0.5-18.1 mg/L (U), 1.1-10.4 mg/L (CSF) and 1.7-22.0 mg/L (VH). At 4 °C, concentrations increased at day 30 to 5.6-74.5 mg/L (VB), 4.6-76.5 mg/L (HB) and < 0.5-21.3 mg/L (U). At RT, concentrations rose to < 0.5-38.5 mg/L (VB), 1.2-94.6 mg/L (HB) and < 0.5-37.5 mg/L (U) at day 30. In CSF, at RT, an increase up to < 0.5-21.2 mg/L was measured, and at 4 °C, a decrease occurred (< 0.5-6.5 mg/L). GHB concentrations in VH remained stable at both temperatures (1.2-20.9 mg/L and < 0.5-26.2 mg/L). The increase of GHB in HB samples with NaF was significantly lower than that without preservation. No correlation was found between the bacterial colonisation and extent of GHB concentration changes.

CONCLUSION

GHB concentrations can significantly increase in post-mortem HB, VB and U samples, depending on storage time, temperature and inter-individual differences. Results in CSF, VH, S and/or specimens with NaF are less affected.

Fostering medical students' clinical reasoning by learning from errors in clinical case vignettes: effects and conditions of additional prompting procedures to foster self-explanations

The present study aims at fostering undergraduate medical students' clinical reasoning by learning from errors. By fostering the acquisition of "negative knowledge" about typical cognitive errors in the medical reasoning process, we support learners in avoiding future erroneous decisions and actions in similar situations. Since learning from errors is based on self-explanation activities, we provided additional prompting procedures to foster the effectiveness of the error-based instructional approach. The extent of instructional support in a web-based learning environment with erroneous clinical case examples was varied in a one-factorial design with three groups by either presenting the cases as (a) unsupported worked examples or by providing the participants with (b) closed prompts in the form of multiple-choice tasks or (c) with open reflection prompts during the learning process. Despite significant learning progress in all conditions, neither prompting procedure improved the learning outcomes beyond the level of the unsupported worked example condition. In contrast to our hypotheses, the unsupported worked example condition was the most effective with respect to fostering clinical reasoning performance. The effects of the learning conditions on clinical reasoning performance was mediated by cognitive load, and moderated by the students' self-efficacy. Both prompting procedures increased extraneous cognitive load. For learners with low self-efficacy, the prompting procedures interfered with effective learning from errors. Although our error-based instructional approach substantially improved clinical reasoning, additional instructional measures intended to support error-based learning processes may overtax learners in an early phase of clinical expertise development and should therefore only be used in moderation.

[The management of unruptured intracranial aneurysms]

The rupture of an intracranial aneurysm is a sudden, unpredictable and potentially severe event. The responsible aneurysm has to be excluded from the cerebral circulation to avoid recurrence. More and more commonly, intracranial aneurysms are detected by coincidence. How to react to these fortuitous discoveries is unclear, because the risk of rupture is difficult to estimate. We present our approach to patients facing this situation and the decision-making process.

Efficacy and safety of sofosbuvir/ledipasvir for the treatment of patients with hepatitis C virus re-infection after liver transplantation

BACKGROUND

Hepatitis C virus (HCV) infection is associated with a particularly poor outcome after liver transplantation. In December 2014, sofosbuvir/ledipasvir (SOF/LDV) fixed-dose combination (FDC) was approved for HCV genotype 1 and 4 in Europe. In orthotopic liver transplantation (OLT) recipients, the interferon-free treatment of HCV re-infection with novel direct-acting antivirals has been demonstrated to be safe and effective in clinical trials, but real-world data are missing. The aim of this study was to investigate the safety and efficacy of SOF/LDV FDC in OLT recipients in the real-life setting.

METHODS

All consecutive OLT patients started on SOF/LDV FDC for 12 or 24 weeks at the University Medical Center Hamburg-Eppendorf and Medical School Hannover between October 2014 and August 2015 were retrospectively analyzed (n = 30). The primary efficacy endpoint was sustained virological response (SVR), i.e., absence of viremia 12 weeks after end of treatment (SVR 12). Liver function tests, creatinine, blood count, and HCV RNA (by polymerase chain reaction assay) were determined at each visit.

RESULTS

SVR was achieved in 29/30 patients (96.67%) treated with SOF/LDV ± ribavirin (RBV) for 12 (n = 4) or 24 weeks (n = 25). Twenty-five patients (86.2%) received RBV. However, in 15 of the 25 patients, RBV administration had to be discontinued because of severe anemia (57.7%). One RBV-treated patient died of a myocardial infarction during antiviral therapy; this event was most likely not directly related to SOF/LDV. Aside from RBV-associated anemia, no severe side effects of the antiviral regimen were observed.

CONCLUSION

Antiviral treatment with SOF/LDV is highly effective, safe, and well tolerated in OLT recipients. The addition of RBV often results in severe anemia, requiring dose reduction or discontinuation.

Effects of intraduodenal infusion of the branched-chain amino acid leucine on ad libitum eating, gut motor and hormone functions, and glycemia in healthy men

BACKGROUND

Branched-chain amino acids (BCAAs), particularly leucine, act as nutrient signals regulating protein synthesis and degradation as well as glucose metabolism. In addition, leucine has been demonstrated in animal experiments to modulate eating and energy homeostasis.

OBJECTIVE

We aimed to characterize the effects of physiologic and supraphysiologic loads of intraduodenal leucine on eating, gut hormone and motor functions, and blood glucose in humans.

DESIGN

Twelve lean men were studied on 3 occasions in a randomized, double-blind order. Antropyloroduodenal motility, plasma ghrelin, cholecystokinin, glucagon-like peptide 1, peptide YY, insulin, glucagon, blood glucose, appetite perceptions, and gastrointestinal symptoms were measured during 90-min intraduodenal infusions of leucine at 0.15 kcal/min (total 3.3 g, 13.5 kcal), 0.45 kcal/min (total 9.9 g, 40.5 kcal), or saline (control). Ad libitum eating from a buffet lunch was quantified immediately after the infusions.

RESULTS

Leucine at 0.45 kcal/min inhibited eating (energy intake by ∼13%, P < 0.05), increased plasma cholecystokinin, slightly reduced blood glucose and increased plasma insulin, and decreased antral pressures (all P < 0.05). Leucine at 0.15 kcal/min had no effect on food intake, blood glucose, or antral pressures but also slightly increased plasma cholecystokinin (P < 0.05). Neither dose affected plasma ghrelin, glucagon, glucagon-like peptide 1 and peptide YY, or pyloric and duodenal pressures. Plasma leucine concentrations were related to the dose of intraduodenal leucine, with substantial increases during both 0.15 and 0.45 kcal/min.

CONCLUSIONS

The effects of intraduodenal infusions of free leucine on eating are probably not primarily mediated by changes in gut motor and hormone functions, with perhaps the exception of cholecystokinin. Instead, increased plasma leucine concentrations may be a potential signal mediating the eating-inhibitory effect of leucine. The study was registered as a clinical trial with the Australia and New Zealand Clinical Trial Registry (www.anzctr.org.au) as ACTRN12613000899741.

[ABOUT JUVENILE NASOPHARYNGEAL ANGIOFIBROMA]

We report the case of a young man with a juvenile nasopharyngeal angiofibroma. In this paper, we will first remind the clinical signs of this pathology and its radiological appearance (localisation and extensions). Then we will explain how radioembolisation techniques were used to facilitate the surgical intervention. Finally we will discuss the histology of this tumor.

Comparative effects of intraduodenal protein and lipid on ghrelin, peptide YY, and leptin release in healthy men

Intraduodenal infusion of lipid or protein potently reduces subsequent energy intake. There is evidence that the underlying mechanisms differ significantly between the two nutrients. While intraduodenal lipid stimulates glucagon-like peptide-1 and CCK much more than protein, the release of insulin and glucagon is substantially greater in response to protein. Ghrelin and PYY are both involved in short-term regulation, while leptin is a long-term regulator, of energy balance; the acute effects of nutrients on leptin release are unclear. We investigated the comparative effects of intraduodenal lipid and protein on plasma ghrelin, PYY, and leptin concentrations. Thirteen lean, young men received 90-min intraduodenal infusions of protein (whey hydrolysate) or lipid (long-chain triglyceride emulsion) at a rate of 3 kcal/min, or saline control, on three separate days. Blood samples were collected at baseline and regularly during infusions. Both lipid and protein potently suppressed plasma ghrelin compared with control (both P < 0.001), with no difference between them. While both lipid and protein stimulated plasma PYY (P < 0.001), the effect of lipid was substantially greater than that of protein (P < 0.001). Neither intraduodenal lipid nor protein affected plasma leptin. In conclusion, intraduodenal lipid and protein have discrepant effects on the release of PYY, but not ghrelin. When considered with our previous findings, it appears that, with the exception of ghrelin, the energy intake-suppressant effects of lipid and protein are mediated by different mechanisms.

Effects of intraduodenal infusion of L-tryptophan on ad libitum eating, antropyloroduodenal motility, glycemia, insulinemia, and gut peptide secretion in healthy men

CONTEXT

Changes in gut motor and hormonal function contribute to the eating-inhibitory and glucose-lowering effects of protein. The effect of amino acids, the digestive products of protein, on gastrointestinal function, eating, and glycemia has not been investigated comprehensively.

OBJECTIVE

We tested the hypothesis that L-tryptophan (L-Trp) stimulates gastrointestinal motor and hormonal functions, inhibits eating, and modulates glycemia. Design, Settings, Participants, and Intervention: Ten healthy, normal-weight men were studied in randomized, double-blind fashion, each receiving a 90-minute intraduodenal infusion of L-Trp at 0.075 (total 6.75 kcal) or 0.15 (total 13.5 kcal) kcal/min or saline (control).

MAIN OUTCOME MEASURES

Antropyloroduodenal motility, plasma ghrelin, cholecystokinin, glucagon-like peptide-1, peptide tyrosine tyrosine, insulin, glucagon, blood glucose, and appetite perceptions were measured. Food intake was quantified from a buffet meal after the infusion.

RESULTS

Intraduodenal L-Trp suppressed antral pressures (P < .05) and stimulated pyloric pressures (P < .01) and markedly increased cholecystokinin and glucagon (both P < .001). Glucagon-like peptide-1 and peptide tyrosine tyrosine increased modestly (both P < .001), but there was no effect on total ghrelin. Insulin increased slightly (P < .05) without affecting blood glucose. Plasma L-Trp increased substantially (P < .001). All effects were dose-related and associated with increased fullness and substantially decreased energy intake (P < .001). There was a strong inverse correlation between energy intake and plasma L-Trp (r = -0.70; P < .001).

CONCLUSIONS

Low caloric intraduodenal loads of L-Trp affect gut motor and hormonal function and markedly reduce energy intake. A strong inverse correlation between energy intake and plasma L-Trp suggests that, beyond gut mechanisms, direct effects of circulating L-Trp mediate its eating-inhibitory effect.

Effects of extracellular phosphate on gene expression in murine osteoblasts

That phosphate homeostasis is tightly linked to skeletal mineralization is probably best underscored by the fact that the phosphaturic hormone FGF23 is primarily expressed by terminally differentiated osteoblasts/osteocytes and that increased circulating FGF23 levels are causative for different types of hypophosphatemic rickets. In contrast, FGF23 inactivation results in hyperphosphatemia, and unexpectedly this phenotype is associated with severe osteomalacia in Fgf23-deficient mice. In this context it is interesting that different cell types have been shown to respond to extracellular phosphate, thereby raising the concept that phosphate can act as a signaling molecule. To identify phosphate-responsive genes in primary murine osteoblasts we performed genome wide expression analysis with cells maintained in medium containing either 1 or 4 mM sodium phosphate for 6 h. As confirmed by qRT-PCR, this analysis revealed that several known osteoblast differentiation markers (Bglap, Ibsp, and Phex) were unaffected by raising extracellular phosphate levels. In contrast, we found that the expression of Enpp1 and Ank, two genes encoding inhibitors of matrix mineralization, was induced by extracellular phosphate, while the expression of Sost and Dkk1, two genes encoding inhibitors of bone formation, was negatively regulated. The ability of osteoblasts to respond to extracellular phosphate was dependent on their differentiation state, and shRNA-dependent repression of the phosphate transporter Slc20a1 in MC3T3-E1 cells partially abolished their molecular response to phosphate. Taken together, our results provide further evidence for a role of extracellular phosphate as a signaling molecule and raise the possibility that severe hyperphosphatemia can negatively affect skeletal mineralization.

Food intake regulating hormones in adult craniopharyngioma patients

INTRODUCTION

Patients with craniopharyngioma (CP) have disturbances of the hypothalamic-pituitary axis and serious comorbidities such as obesity. We hypothesized that the secretion of hormones regulating the nutritional status is altered in adult patients with CP compared with patients with non-functioning pituitary adenoma (NFPA).

METHODS

WE INCLUDED 40 CP (50% MALES, MEAN AGE: 49.6±14.3 years) and 40 NFPA (72.5% males, mean age: 63.4±9.8 years) patients. We measured glucose, insulin, leptin, total ghrelin, peptide-YY (PYY) and cholecystokinin (CCK) during oral glucose tolerance test (OGTT). Fat mass (FM) was determined by dual X-ray absorptiometry.

RESULTS

Gender distribution was not significantly different, but CP patients were significantly younger (P<0.001). CP patients had significantly higher BMI and FM than NFPA patients (BMI 32±8 vs 28±4 kg/m(2), P=0.009 and FM 37±9 vs 33±9%, P=0.02). Fasting glucose level (84±12 vs 78±11 mg/dl, P=0.03), leptin (27.9±34.2 vs 11.9±11.6 μg/l, P=0.008) and leptin levels corrected for percentage FM (0.66±0.67 vs 0.32±0.25 μg/l%, P=0.005) were significantly higher in CP than in NFPA patients, whereas ghrelin was significantly lower (131±129 vs 191±119 ng/l, P=0.035). Insulin, PYY and CCK did not differ significantly between groups. After glucose load, leptin decreased significantly in CP patients (P=0.019). In both groups, ghrelin decreased significantly during OGTT (both P<0.001). The percentage decline was significantly smaller for CP. PYY and CCK increased equally after glucose in both groups.

CONCLUSION

Our patients with CP have more metabolic complications than our patients with NFPA. The levels of leptin and ghrelin at fasting status and after glucose seem to be altered in CP, whereas changes in insulin, PYY and CCK do not seem to be responsible for the metabolic changes in these patients.

[Transcranial color-coded sonography in the management of patients with cervical and intracranial arterial stenosis]

Technological innovations have endowed the development of powerful tools in medical imaging, such as transcranial color-coded sonography. In addition to other imaging techniques, its relevance in cerebrovascular disorders is increasing. This article aims to describe the technique through specification of its current indications in patients with arterial cervical and intracranial stenosis.

[Multidisciplinary treatment of glioblastoma]

Glioblastoma is a primary brain tumor that occurs most often in elderly patients. Despite improved management, the prognosis of this cancer remains poor. This review describes the multidisciplinary management of the patient with glioblastoma. It includes surgery, radiation therapy and chemotherapy.

The impact of insulin-independent, glucagon-induced suppression of total ghrelin on satiety in obesity and type 1 diabetes mellitus

AIMS/HYPOTHESIS

The mechanisms underlying glucagon-induced satiety are incompletely understood. The glucagon-induced reduction in total ghrelin exerted at the hypothalamo-pituitary level might be responsible for this effect. Here we investigated glucagon-suppressive effects on circulating total and acyl-ghrelin, both in obesity and in type 1 diabetes mellitus (T1DM), with respect to the role of glucagon in appetite control. We further aimed to identify a possible mechanistic impact of changes in endogenous insulin.

METHODS

In our prospective, double-blinded, placebo-controlled study, we investigated the endocrine and metabolic responses to intramuscular glucagon administration in 13 patients with T1DM (6 males, 7 females; body mass index [BMI] 24.8 ± 0.95 kg/m(2)), 11 obese participants (OP; 5 males, 6 females; BMI 34.4 ± 1.7 kg/m(2)), and 13 healthy lean participants (LP; 6 males, 7 females; BMI 21.7 ± 0.6 kg/m(2)).

RESULTS

As compared with placebo, glucagon significantly increased satiety index in T1DM and in LP (P < .001) but failed to induce satiety in OP (P = .152). Total ghrelin significantly decreased after glucagon administration in all study groups (P < .01). Similarly, acyl-ghrelin significantly decreased in LP (P < .01). However, acyl-ghrelin concentrations showed no change in OP (P = .248) and even increased substantially in T1DM (P < .01). Changes in acyl-ghrelin correlated positively with changes in nonesterified fatty acid concentrations in all groups (r = 0.31-0.43; P < .01).

CONCLUSIONS/INTERPRETATION

Glucagon-induced satiety was preserved in T1DM but not in obesity. This effect was unrelated to changes in total or acylated ghrelin and was independent of endogenous insulin release. In contrast to the insulin-independent glucagon-induced suppression of total ghrelin, glucagon- and/or insulin-induced modification of lipolysis may determine changes in acylated ghrelin.

[Cerebrotendinous xanthomatosis, a rare, severe, but treatable metabolic disorder]

Cerebrotendinous xanthomatosis (CTX) is a rare and treatable autosomal recessive disease. The diagnosis should be suspected in the presence of a suggestive clinical triad characterized by early-onset cataract, tendinous xanthomata and neurological symptoms and signs, notably cerebellar ataxia, mental retardation and pyramidal syndrome.The diagnosis is confirmed by demonstrating an increased blood level of cholestanol, or/and by molecular genetic analysis.In typical cases, brain MRI shows bilateral hyperintensity of the cerebellar nucleus dentatus together with cerebral atrophy and leukoencephalopathy. The treatment is based on the administration of chenodeoxycholic acid. The aim is to restore the negative feedback on the enzymatic cascade altered by mutation in the gene CYP27 which induces a 27-hydroxylase deficiency

Cholecystokinin revisited: CCK and the hunger trap in anorexia nervosa

Objective

Despite a number of studies in the past decades, the role of Cholecystokinin (CCK) in anorexia nervosa (AN) has remained uncertain. In this study a highly specific assay for the biologically active part of CCK was used in patients with bulimic as well as with the restricting type of AN who were followed over the course of weight gain.

Methods

Ten patients with restricting and 13 with bulimic AN were investigated upon admission (T0), after a weight gain of at least 2 kg on two consecutive weighting dates (T1), and during the last week before discharge (T2) from inpatient treatment in a specialized clinic. Blood samples were drawn under fasting conditions and 20 and 60 minutes following a standard meal (250 kcal). Data were compared to those of eight controls matched for sex and age. Gastrointestinal complaints of patients were measured by a questionnaire at each of the follow-up time points.

Results

At admission, AN patients exhibited CCK-levels similar to controls both prior to and after a test meal. Pre and post-meal CCK levels increased significantly after an initial weight gain but decreased again with further weight improvement. CCK release was somewhat lower in bulimic than in restricting type AN but both subgroups showed a similar profile. There was no significant association of CCK release to either initial weight or BMI, or their changes, but CCK levels at admission predicted gastrointestinal symptom improvement during therapy.

Conclusions

Normal CCK profiles in AN at admission indicates hormonal responses adapted to low food intake while change of eating habits and weight gain results in initially increased CCK release (counteracting the attempts to alter eating behavior) that returns towards normal levels with continuous therapy.

[Horner's syndrome revealing a spontaneous carotid artery dissection]

We report a case of spontaneous carotid artery dissection suspected by the appearance of Horner's syndrome. Under medical treatment, the intramural hematoma resolved within 3 months. The patient had an uneventful recovery, without any residual neurologic deficit. Spontaneous arterial dissection is responsible for a hematoma in the arterial wall without significant trauma. The pathogenesis remains unknown. Predisposing factors seem to exist. The clinical presentation is variable mainly due to local compression of adjacent structures which can precede a transient or permanent neurological deficit. The diagnosis is confirmed by Doppler US, CT angiography or magnetic resonance angiography, the best optional investigations. The treatment mainly consists of stroke prevention by anticoagulation versus antiplatelet therapy. The role of surgery and/or endovascular techniques has not yet been confirmed.

Influence of acute exposure to high altitude on basal and postprandial plasma levels of gastroenteropancreatic peptides

Acute mountain sickness (AMS) is characterized by headache often accompanied by gastrointestinal complaints that vary from anorexia through nausea to vomiting. The aim of this study was to investigate the influence of high altitude on plasma levels of gastroenteropancreatic (GEP) peptides and their association to AMS symptoms. Plasma levels of 6 GEP peptides were measured by radioimmunoassay in 11 subjects at 490 m (Munich, Germany) and, after rapid passive ascent to 3454 m (Jungfraujoch, Switzerland), over the course of three days. In a second study (n = 5), the same peptides and ghrelin were measured in subjects who consumed standardized liquid meals at these two elevations. AMS symptoms and oxygen saturation were monitored. In the first study, both fasting (morning 8 a.m.) and stimulated (evening 8 p.m.) plasma levels of pancreatic polypeptide (PP) and cholecystokinin (CCK) were significantly lower at high altitude as compared to baseline, whereas gastrin and motilin concentrations were significantly increased. Fasting plasma neurotensin was significantly enhanced whereas stimulated levels were reduced. Both fasting and stimulated plasma motilin levels correlated with gastrointestinal symptom severity (r = 0.294, p = 0.05, and r = 0.41, p = 0.006, respectively). Mean O(2)-saturation dropped from 96% to 88% at high altitude. In the second study, meal-stimulated integrated (= area under curve) plasma CCK, PP, and neurotensin values were significantly suppressed at high altitude, whereas integrated levels of gastrin were increased and integrated VIP and ghrelin levels were unchanged. In summary, our data show that acute exposure to a hypobaric hypoxic environment causes significant changes in fasting and stimulated plasma levels of GEP peptides over consecutive days and after a standardized meal. The changes of peptide levels were not uniform. Based on the inhibition of PP and neurotensin release a reduction of the cholinergic tone can be postulated.

Campylobacter jejuni induces extra-intestinal immune responses via Toll-like-receptor-4 signaling in conventional IL-10 deficient mice with chronic colitis

Campylobacter jejuni is one of the predominant causes for foodborne bacterial infections worldwide. We investigated whether signaling of C. jejuni-lipoproteins and -lipooligosaccharide via Toll-like-receptor (TLR) -2 and -4, respectively, is inducing intestinal and extra-intestinal immune responses following infection of conventional IL-10(-/-) mice with chronic colitis. At day 3 following oral infection, IL-10(-/-) mice lacking TLR-2 or TLR-4 harbored comparable C. jejuni strain ATCC 43431 loads in their colon. Interestingly, infected TLR-4(-/-) IL-10(-/-) mice displayed less compromized epithelial barrier function as indicated by lower translocation rates of live gut commensals into mesenteric lymphnodes (MLNs), and exhibited less distinct B lymphocyte responses in their colonic mucosa as compared to naїve IL-10(-/-) controls. Furthermore, in extra-intestinal compartments such as MLNs and spleens, abundance of myeloid cells was less distinct whereas relative percentages of activated T helper cells and cytotoxic T cells were higher in spleens and dendritic cells more abundant in MLNs of infected IL-10(-/-) animals lacking TLR-4 as compared to IL-10(-/-) controls. Taken together, in conventionally colonized IL-10(-/-) mice, TLR-4, but not TLR-2, is involved in mediating extra-intestinal pro-inflammatory immune responses following C. jejuni infection. Thus, conventional IL-10(-/-) mice are well suited to further dissect mechanisms underlying Campylobacter infections in vivo.

Effects of fat, protein, and carbohydrate and protein load on appetite, plasma cholecystokinin, peptide YY, and ghrelin, and energy intake in lean and obese men

While protein is regarded as the most satiating macronutrient, many studies have employed test meals that had very high and unsustainable protein contents. Furthermore, the comparative responses between lean and obese subjects and the relationships between energy intake suppression and gut hormone release remain unclear. We evaluated the acute effects of meals with modest variations in 1) fat, protein, and carbohydrate content and 2) protein load on gastrointestinal hormones, appetite, and subsequent energy intake in lean and obese subjects. Sixteen lean and sixteen obese men were studied on four occasions. Following a standardized breakfast, they received for lunch: 1) high-fat (HF), 2) high-protein (HP), 3) high-carbohydrate/low-protein (HC/LP), or 4) adequate-protein (AP) isocaloric test meals. Hunger, fullness, and gut hormones were measured throughout, and at t = 180 min energy intake at a buffet meal was quantified. In lean subjects, hunger was less and fullness greater following HF, HP, and AP compared with HC/LP meals, and energy intake was less following HF and HP compared with HC meals (P < 0.05). In the obese subjects, hunger was less following HP compared with HF, HC/LP, and AP meals, and energy intake was less following HP and AP compared with HF and HC meals (P < 0.05). There were no major differences in hormone responses to the meals among subject groups, but the CCK and ghrelin responses to HP and AP were sustained in both groups. In conclusion, HP meals suppress energy intake in lean and obese subjects, an effect potentially mediated by CCK and ghrelin, while obese individuals appear to be less sensitive to the satiating effects of fat.

Subjective and Biological Weight-Related Parameters

Objective: Administration of atypical antipsychotics often induces significant weight gain and metabolic changes. Little is known about subjective weight-related parameters in adolescent patients. Therefore, this cross-sectional, explorative study aimed to assess these parameters and their relationship with biological weight-related parameters. Method: 74 patients (mean age: 19.9 [SD ± 2.3] years; 66.2% male) with schizophrenia under clozapine or olanzapine treatment were examined. Subjective well-being, eating behavior, body perception and social functioning were assessed, using the Three-Factor-Eating-Questionnaire, FKB-20 Body Perception Questionnaire, Subjective Well-being under Neuroleptics, Short Form and Global Assessment of Functioning. Patients’ biological weight-related parameters were measured as well. Gender differences as well as associations between subjective and biological weight-related parameters were evaluated. Results: Female patients reported significantly worse negative body appraisal and physical functioning than males. An elevated BMI was associated with impaired physical functioning in females and with negative body appraisal and hunger in males. Conclusions: In our sample of young patients with schizophrenia unter treatment with atypical antipsychotics, an elevated BMI was associated with impaired physical functioning and negative body appraisal, respectively. Bearing in mind the high risk of obesity in this population, the mentioned impairments should be accounted for, especially in terms of compliance and quality of life.

Duodenal lipid-induced symptom generation in gastroesophageal reflux disease: role of apolipoprotein A-IV and cholecystokinin

BACKGROUND

  Duodenal lipid intensifies the perception of esophageal acid perfusion. Recently, we showed that genes implicated in lipid absorption were upregulated in the duodenum of fasting gastro-esophageal reflux disease (GERD) patients. This suggests that chylomicron production and secretion may be enhanced and, consequently, the release of apolipoprotein A-IV (apoA-IV), a chylomicron-derived signaling protein. ApoA-IV may stimulate release of cholecystokinin (CCK), an activator of vagal afferents. This study evaluated putative involvement of abnormal apoA-IV and CCK responses to lipid in GERD.

METHODS

  Ten GERD patients and 10 healthy volunteers (HV) underwent duodenal perfusion with Intralipid 20%, 2 kcal min(-1) , for 60 min. Symptoms were scored, blood samples collected every 15 min during lipid perfusion and 15 min after discontinuation when duodenal biopsies were taken. Plasma and mucosal concentrations of apoA-IV and CCK and transcript levels of 21 genes implicated in lipid absorption, differentially expressed under fasting conditions, were quantified.

KEY RESULTS

  Heartburn (P = 0.003), abdominal discomfort (P = 0.037) and nausea (P = 0.008) only increased significantly during lipid infusion in GERD patients. Following lipid infusion mean mucosal apoA-IV concentration was lower in GERD patients compared with HV (P = 0.023), whereas plasma concentration tended to be elevated (P = 0.068). Mean mucosal CCK concentration was also lower in GERD patients (P = 0.009). Two genes, HIBADH and JTB, were upregulated in GERD patients (P = 0.008 and P = 0.038, respectively).

CONCLUSIONS & INFERENCES

  Our results suggest excessive duodenal lipid-induced release of apoA-IV and CCK in GERD. We postulate that the resulting heightened activation of duodenal vagal afferents may underlie central sensitization, thereby increasing the perception of reflux events.

Campylobacter jejuni infection of infant mice: acute enterocolitis is followed by asymptomatic intestinal and extra-intestinal immune responses

Campylobacter (C.) jejuni is among the leading bacterial agents causing enterocolitis worldwide. Despite the high prevalence of C. jejuni infections and its significant medical and economical consequences, intestinal pathogenesis is poorly understood. This is mainly due to the lack of appropriate animal models. In the age of 3 months, adult mice display strong colonization resistance (CR) against C. jejuni. Previous studies underlined the substantial role of the murine intestinal microbiota in maintaining CR. Due to the fact that the host-specific gut flora establishes after weaning, we investigated CR against C. jejuni in 3-week-old mice and studied intestinal and extra-intestinal immunopathogenesis as well as age dependent differences of the murine colon microbiota. In infant animals infected orally immediately after weaning C. jejuni strain B2 could stably colonize the gastrointestinal tract for more than 100 days. Within six days following infection, infant mice developed acute enterocolitis as indicated by bloody diarrhea, colonic shortening, and increased apoptotic cell numbers in the colon mucosa. Similar to human campylobacteriosis clinical disease manifestations were self-limited and disappeared within two weeks. Interestingly, long-term C. jejuni infection was accompanied by distinct intestinal immune and inflammatory responses as indicated by increased numbers of T- and B-lymphocytes, regulatory T-cells, neutrophils, as well as apoptotic cells in the colon mucosa. Strikingly, C. jejuni infection also induced a pronounced influx of immune cells into extra-intestinal sites such as liver, lung, and kidney. Furthermore, C. jejuni susceptible weaned mice harbored a different microbiota as compared to resistant adult animals. These results support the essential role of the microflora composition in CR against C. jejuni and demonstrate that infant mouse models resemble C. jejuni mediated immunopathogenesis including the characteristic self-limited enterocolitis in human campylobacteriosis. Furthermore, potential clinical and immunological sequelae of chronic C. jejuni carriers in humans can be further elucidated by investigation of long-term infected infant mice. The observed extraintestinal disease manifestations might help to unravel the mechanisms causing complications such as reactive arthritis or Guillain-Barré syndrome.

Effects on metabolic variables after 12-month treatment with a new once-a-week sustained-release recombinant growth hormone (GH: LB03002) in patients with GH deficiency

INTRODUCTION

GH substitution in GH deficiency (GHD) must be subcutaneously administered daily. A new sustained-release formulation of GH (LB03002) has been developed, which has to be injected once a week. As a substudy to the phase III study, we performed this prospective study to evaluate the influence of LB03002 on metabolic variables and hormones.

METHODS

Eleven patients with GHD [four women/seven men, 58 years (29-69 years)] without GH therapy were included in the study. Eight patients were treated with LB03002 for 12 months and three patients received placebo for 6 months followed by LB03002 for 6 months. A 3-h oral glucose tolerance test (OGTT) was performed at study entry and at study end. Additionally, IGF-I, cholesterol, LDL, HDL, triglycerides, leptin, ghrelin, HbA1c and C-peptide were measured. Body composition was evaluated by dual-energy X-ray absorptiometry (DXA), and waist/hip ratio (WHR) and waist/height (WHtR) ratio were measured by tape and scale.

RESULTS

Multiple of upper limit of normal (xULN) of IGF-I (0·23 (0·09-0·4) vs 0·71 (0·4-1·04), P < 0·01), WHR (0·98 (0·86-1·04) vs 1·01 (0·86-1·05), P < 0·05) and ghrelin levels [119·8 ng/l (67·7-266·6) vs 137 ng/l (67-289·5), P < 0·05] were significantly higher, whereas fat mass (FM) [34·7% (20·4-49·2) vs 32·4% (16·7-48·5), P < 0·05] and leptin [11·2 μg/l (3·3-55·7) vs 7·05 μg/l (2·4-54·3), P < 0·05] were significantly lower at study end. Glucose, insulin, HOMA-IR, ISI, HOMA-β, C-peptide and HbA1c during OGTT were not significantly different before and after GH substitution, neither were BMI, WHtR, bone mineral density and lipid variables.

CONCLUSION

Substitution with LB03002 showed statistically significant reduction in FM, which reduces leptin levels and increases ghrelin levels but does not seem to influence glucose and lipid metabolism.

Slowly and rapidly digested fat emulsions are equally satiating but their triglycerides are differentially absorbed and metabolized in humans

Little is known about the effect of dietary fat emulsion microstructure on plasma TG concentrations, satiety hormones, and food intake. The aim of this study was to structure dietary fat to slow digestion and flatten postprandial plasma TG concentrations but not increase food intake. Emulsions were stabilized by egg lecithin (control), sodium sterol lactylate, or sodium caseinate/monoglyceride (CasMag) with either liquid oil or a liquid oil/solid fat mixture. In a randomized, double-blind, crossover design, 4 emulsions containing 30 g of fat in a 350-mL preload were consumed by 10 men and 10 women (BMI = 25.1 ± 2.8 kg/m(2); age = 58.8 ± 4.8 y). Pre- and postprandial plasma TG, cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), and peptide YY (PYY) concentrations and food intake were measured. In a second experiment in a subset of the participants (n = 8, 4 men and 4 women), (13)C-labeled mixed TG was incorporated into 2 different emulsions and breath (13)C was measured over 6 h. In the first experiment, the postprandial rise in plasma TG concentrations following the CasMag-stabilized emulsion containing 30% solid fat was lower than all other emulsions at 90 and 120 min (P < 0.05). Plasma CCK (P < 0.0001), GLP-1 (P < 0.01), and PYY (P < 0.001) concentrations were also reduced following this emulsion compared with control. Food intake at a test meal, eaten 3 h after the preload, did not differ among the emulsions. In the second experiment, when measured by the (13)C breath test, 25% of the TG in the CasMag emulsion was absorbed and metabolized compared with control. In conclusion, fat can be structured to decrease its effect on plasma TG concentrations without increasing food intake.

Effect of GABA-ergic mechanisms on synaptosomal NO synthesis and the nitrergic component of NANC relaxation in rat ileum

BACKGROUND

γ-Aminobutyric acid (GABA) acts on specific neural receptors [A, B and C(Aρ)] to modulate gastrointestinal function. The precise role of GABA receptor activation in the regulation of presynaptic nitric oxide (NO) synthesis in nerve terminals is unknown.

METHODS

Rat ileal nerve terminals were isolated by differential centrifugation. Nitric oxide synthesis was analysed using a L-[(3) H]arginine assay. In vitro studies were performed under non-adrenergic non-cholinergic (NANC) conditions on isolated ileal segments.

KEY RESULTS

γ-Aminobutyric acid inhibited NO synthesis significantly (n = 6, P < 0.05) [(fmol mg(-1) min(-1)) control: 27.7 ± 1.5, 10(-6) mol L(-1): 19.7 ± 1.3; 10(-5) mol L(-1): 17.5 ± 3.0]. This effect was antagonized by the GABA A receptor antagonist bicuculline and the GABA C receptor antagonist (1,2,5,6-tetrahydropyridin-4-yl)methylphosphinic acid (TPMPA), but not by the GABA B receptor antagonist SCH 50911. The GABA A receptor agonist muscimol [(fmol mg(-1) min(-1)) control: 27.6 ± 1.0, 10(-6) mol L(-1): 19.1 ± 1.7, n = 5, P < 0.05] and the GABA C receptor agonist cis-4-aminocrotonic acid (CACA) [(fmol mg(-1) min(-1)) control: 29.5 ± 3.2, 10(-3) mol L(-1): 20.3 ± 2.5, n = 6, P < 0.05], mimicked the GABA-effect, whereas the GABA B agonist baclofen was ineffective. Bicuculline reversed the inhibitory effect of muscimol, TPMPA antagonized the effect of CACA. In functional experiments the GABA A and C receptor agonists reduced the NANC relaxation induced by electrical field stimulation in rat ileum by about 40%. After NOS-inhibition by Nε-nitro-L-arginine methyl ester (L-NAME) the GABA A receptor agonist had no effect, whereas the GABA C receptor agonist still showed a residual response.

CONCLUSIONS & INFERENCES

γ-Aminobutyric acid inhibits neural NO synthesis in rat ileum by GABA A and GABA C(Aρ) receptor-mediated mechanisms.

Marked differences in gustatory and gastrointestinal sensitivity to oleic acid between lean and obese men

BACKGROUND

Both orosensory stimulation and feedback from the gastrointestinal tract contribute to energy intake regulation.

OBJECTIVE

We evaluated the hypothesis that overweight or obese subjects would be less sensitive to both oral and intraduodenal oleic acid exposure than would lean subjects.

DESIGN

Eleven overweight or obese and 8 lean men were studied on 2 occasions, during which antropyloroduodenal pressures, plasma cholecystokinin and peptide YY, and appetite were measured during 90-min intraduodenal infusions of saline or oleic acid (18:1 load: 0.78 kcal/min); energy intake (buffet lunch) was determined immediately afterward. Oral detection thresholds for 18:1 and recent dietary intake (2-d recall) were also quantified.

RESULTS

In lean subjects, the number of isolated pyloric pressure waves (IPPWs) was greater during 18:1 infusion than during saline infusion (P < 0.05); no significant differences were observed between the 18:1 and saline infusions in the overweight or obese subjects. In both groups, 18:1 stimulated plasma cholecystokinin and peptide YY and suppressed energy intake compared with saline (P < 0.05), with trends for reduced cholecystokinin and energy intake responses in the overweight or obese subjects. Detection thresholds for 18:1 were greater in overweight or obese (7.9 ± 0.1 mmol/L) than in lean (4.1 ± 0.4 mmol/L) subjects (P < 0.05). Overweight or obese subjects had greater recent energy (P < 0.05) and fat (P = 0.07) intakes than did lean subjects. There was a direct relation (r = 0.669) of body mass index with 18:1 detection thresholds and inverse relations (r < -0.51) of IPPWs with body mass index and 18:1 detection thresholds (P < 0.05).

CONCLUSIONS

The ability to detect oleic acid both orally and within the gastrointestinal tract is compromised in obese men, and oral and gastrointestinal responses to oleic acid are related. This trial was registered at www.actr.org.au (Australian New Zealand Clinical Trials Registry) as 12609000557235.

Effects of acute dietary restriction on gut motor, hormone and energy intake responses to duodenal fat in obese men

BACKGROUND

Previous patterns of energy intake influence gastrointestinal function and appetite, probably reflecting changes in small-intestinal nutrient-mediated feedback. Obese individuals consume more fat and may be less sensitive to its gastrointestinal and appetite-suppressant effects than lean individuals.

OBJECTIVE

To evaluate the hypothesis that, in obese individuals, the effects of duodenal fat on gastrointestinal motor and hormone function, and appetite would be enhanced by a short period on a very-low-calorie diet (VLCD).

METHODS

Eight obese men (body mass index 34±0.6  kg  m(-2)) were studied on two occasions, before (V1), and immediately after (V2), a 4-day VLCD. On both occasions, antropyloroduodenal motility, plasma cholecystokinin (CCK), peptide-YY (PYY) and ghrelin concentrations, and appetite perceptions were measured during a 120-min intraduodenal fat infusion (2.86  kcal  min(-1)). Immediately afterwards, energy intake was quantified.

RESULTS

During V2, basal pyloric pressure and the number and amplitude of isolated pyloric pressure waves (PWs) were greater, whereas the number of antral and duodenal PWs was less, compared with V1 (all P<0.05). Moreover, during V2, baseline ghrelin concentration was higher; the stimulation of PYY and suppression of ghrelin by lipid were greater, with no difference in CCK concentration; and hunger and energy intake (kJ; V1: 4378±691, V2: 3634±700) were less (all P<0.05), compared with V1.

CONCLUSIONS

In obese males, the effects of small-intestinal lipid on gastrointestinal motility and some hormone responses and appetite are enhanced after a 4-day VLCD.

[Third cranial nerve palsies in childhood. A case report of sellar germ cell tumor]

PURPOSE

Third cranial nerve palsies are unfrequent in childhood and adolescence and are most often congenital. The association of sellar germ cell tumor and ophthalmoplegia is considered as being very rare at this age.

CASE REPORT

A 11-year-old young girl was examined in emergency with a third left cranial nerve partial palsy associated with one- year duration history of hypopituitarism with insipid diabetes and growth retardation. Cerebral IRM revealed a tumor of the pituitary gland. In histopathological examination of pituitary gland biopsies, lesions were compatibles with a sellar germ cell tumor.

CONCLUSION

Although they are most often of a congenital nature, third cranial nerve palsies in childhood may be secondary to other causes that should be always taken in mind. When they are secondary to a sellar tumor and according to the clinical presentation and the IRM, the histopahological examination of biopsies is mandatory to have a precise diagnosis.

Influence of pegvisomant on serum ghrelin and leptin levels in acromegalic patients

INTRODUCTION

Pegvisomant (peg) is a GH receptor antagonist. In de novo acromegalic patients with high GH levels, ghrelin and leptin levels are reduced, suggesting a direct GH-mediated effect. The aim of our study was to evaluate whether peg treatment in acromegalic patients may abolish the GH impact on ghrelin and leptin levels.

METHODS

Ghrelin, leptin and endogenous GH were measured in ten peg-treated acromegalic patients (three females/seven males, 47 years (28-57)), ten patients with active (act) and ten patients with inactive disease (inact) as well as in ten gender-, age- and body mass index (BMI)-matched healthy volunteers (controls). Endogenous GH was measured using a special in-house assay without interference by peg; total ghrelin and leptin were determined using a commercial RIA and an immunofluorometric in-house assay respectively.

RESULTS

Age and BMI did not differ significantly between groups. Endogenous GH was significantly higher in peg (6.3 μg/l (1.5-41)) and act (9.3 μg/l (1.7-70)) compared with controls (0.1 μg/l (0.1-3.1)) and inact (0.35 μg/l (0.1-2.0), P<0.001). Ghrelin was significantly higher in peg (232  ng/l (96-351)) compared with act (102 ng/l (33-232), P<0.01), whereas ghrelin was not significantly different between the other groups. Leptin was highest in controls (19 μg/l (4-57)) and lowest in act (6 μg/l (2-21)), but this difference did not reach significance.

CONCLUSION

Treatment with peg seems to disrupt the feedback loop of ghrelin and GH, leading to elevated ghrelin levels. Furthermore, peg therapy appears not to have a strong impact on leptin levels, as acromegalic patients with and without peg treatment showed similar leptin levels.

Hypobaric hypoxia causes body weight reduction in obese subjects

The reason for weight loss at high altitudes is largely unknown. To date, studies have been unable to differentiate between weight loss due to hypobaric hypoxia and that related to increased physical exercise. The aim of our study was to examine the effect of hypobaric hypoxia on body weight at high altitude in obese subjects. We investigated 20 male obese subjects (age 55.7 +/- 4.1 years, BMI 33.7 +/- 1.0 kg/m(2)). Body weight, waist circumference, basal metabolic rate (BMR), nutrition protocols, and objective activity parameters as well as metabolic and cardiovascular parameters, blood gas analysis, leptin, and ghrelin were determined at low altitude (LA) (Munich 530 m, D1), at the beginning and at the end of a 1-week stay at high altitude (2,650 m, D7 and D14) and 4 weeks after returning to LA (D42). Although daily pace counting remained stable at high altitude, at D14 and D42, participants weighed significantly less and had higher BMRs than at D1. Food intake was decreased at D7. Basal leptin levels increased significantly at high altitude despite the reduction in body weight. Diastolic blood pressure was significantly lower at D7, D14, and D42 compared to D1. This study shows that obese subjects lose weight at high altitudes. This may be due to a higher metabolic rate and reduced food intake. Interestingly, leptin levels rise in high altitude despite reduced body weight. Hypobaric hypoxia seems to play a major role, although the physiological mechanisms remain unclear. Weight loss at high altitudes was associated with clinically relevant improvements in diastolic blood pressure.

Effect of meglitinides on postprandial ghrelin secretion pattern in type 2 diabetes mellitus

BACKGROUND

A progressive weight gain is associated with various pharmacological options improving glycemic control in type 2 diabetes mellitus (T2DM). Ghrelin has been implicated in the regulation of feeding behavior and energy balance in humans. Based on evidence that functional ATP-sensitive channels are present in ghrelin-producing cells, we hypothesized that meglitinides may affect circulating ghrelin levels in subjects with type 2 diabetes.

METHODS

In a single-blinded randomized three-period crossover study (n = 20), repaglinide or nateglinide was given in combination with metformin for two treatment periods over a 1-week period, respectively, separated by a 1-week treatment with placebo. Liquid meal challenge tests (LMCTs) with single preprandial doses of repaglinide (2 mg), nateglinide (120 mg), or placebo were performed at the end of each treatment period. Ten control subjects without diabetes underwent a single LMCT without any medication.

RESULTS

Fasting ghrelin concentrations were not different between all treatments and between patients with diabetes and control subjects. Subjects with T2DM treated with placebo showed no suppression of ghrelin in the LMCT. After administration of meglitinides a nadir of serum ghrelin was observed at 60 min (8.6% of baseline [P = 0.038] for repaglinide and 7.5% of baseline [P = 0.081] for nateglinide), which was similar to the secretion pattern seen in control subjects. No correlations between postprandial insulin or glucose levels and circulating ghrelin concentrations were observed.

CONCLUSIONS

Treatment with meglitinides reconstructed postprandial ghrelin secretion patterns to those of controls without diabetes. This observation may help to improve the control of feeding behavior in patients with T2DM.

Influence of long-term growth hormone replacement on leptin and ghrelin in GH deficiency before and after glucose load

INTRODUCTION

This cross-sectional study was performed to evaluate the effect of long-term GH substitution on leptin and ghrelin in GH deficiency (GHD).

METHODS

Leptin and ghrelin were measured after glucose load for 3 h in 52 pat and 10 age- and BMI-matched healthy controls. 22 GHD pat were on GH substitution (GH-Sub) for a median of 10 yr (range 2-27 yr). 30 age- and BMI-matched GHD pat were not substituted for at least 2 yr (non-Sub).

RESULTS

Basal leptin (8 microg/l (1-130) vs. 16 microg/l (3-89), p<0.05) and AUC of leptin (p<0.05) was significantly lower in GH-Sub compared to non-Sub. In the control group, leptin was higher compared to GH-Sub and similar to non-Sub (19 microg/l (4-57)). Ghrelin (baseline: non-Sub 113 ng/l (61-270), GH-Sub 145 ng/l (83-280), controls 131 ng/l (83-274)) were slightly but not significantly lower for non-Sub. After glucose load, a significant decrease in leptin appeared in both GHD groups, but not in the control group. Ghrelin decreased significantly in all groups.

CONCLUSION

Lipolytic GH causes lower leptin in GH-Sub. The reason for similar ghrelin might be the compensating effect of acute GH suppression and stimulating low fat mass on ghrelin. Leptin regulation after glucose load is impaired in GHD, whereas ghrelin regulation seems to be not effected.

The droplet size of intraduodenal fat emulsions influences antropyloroduodenal motility, hormone release, and appetite in healthy males

BACKGROUND

The presence of fat in the small intestine modulates gastrointestinal motility, stimulates plasma cholecystokinin and peptide YY release, and suppresses appetite and energy intake. These effects are dependent on the lipolysis of fat.

OBJECTIVE

Our aim was to evaluate the hypothesis that increasing the droplet size of a fat emulsion would attenuate these effects.

DESIGN

Ten healthy, lean males were studied on 4 separate occasions in single-blind randomized order. Antropyloroduodenal pressures, plasma triglycerides, cholecystokinin, peptide YY, and appetite were measured during 120-min intraduodenal infusions of fat emulsions comprising 3 different droplet sizes: 1) 0.26 microm (LE-0.26), 2) 30 microm (LE-30), and 3) 170 microm (LE-170) in addition to saline (control). Energy intake at a buffet lunch was quantified immediately after the infusions.

RESULTS

Increasing the droplet size of the lipid emulsion was associated with diminished suppression of antral (r = 0.75, P < 0.01) and duodenal (r = 0.80, P < 0.01) pressure waves and with stimulation of isolated (r = -0.72, P < 0.01) and basal (r = -0.83, P < 0.01) pyloric pressures. Increasing the droplet size was also associated with attenuation of the stimulation of plasma triglycerides (r = -0.73, P < 0.001), cholecystokinin (r = -0.73, P < 0.001), and peptide YY (r = -0.83, P < 0.001) as well as with reductions in the suppression of hunger (r = 0.75, P < 0.01) and energy intake (r = 0.66, P < 0.001).

CONCLUSIONS

The acute effects of intraduodenal fat emulsions on gastrointestinal function and appetite are dependent on fat droplet size. These observations have implications for the design of functional foods to maximize effects on those gut functions that are involved in the suppression of appetite.

Circadian variation of rectal sensitivity and gastrointestinal peptides in healthy volunteers

The aim of our study was to identify diurnal variation of perception of rectal distension and the release of gastroenteropancreatic hormones. In 12 healthy male volunteers (25 years, range 22-32), a rectal balloon distension was performed. Rectal perception thresholds (minimal, urge and pain) and rectal compliance were double-measured with a computer-controlled barostat at seven standardized time points during the day (from 16.00 to 14.00 hours the following day). Blood samples were taken 30 min before and after each rectal distension procedure to determine plasma levels of cholecystokinin (CCK), pancreatic polypeptide (PP) and motilin. Sensory thresholds for urge and pain varied significantly with the time of day, with higher threshold levels in the evening than in the morning hours. Bowel wall compliance showed as well-significant variance at pain threshold and was higher during daytime than in the evening or at night. In contrast to motilin, release of CCK and PP also showed a significant variation depending on daytime. Perception of rectal distension stimuli as well as compliance was independent of intake of food and peptide hormone levels, but CCK and PP levels increased with food, and PP levels decreased with rectal distension. Significant differences in the perception of rectal distension stimuli for urge and pain depending on daytime were found, but the release of gastrointestinal peptides seemed not to be involved. This circadian variation needs to be taken into account in patients and volunteer studies.

Xenon anesthesia impairs hepatic oxygenation and perfusion in healthy pigs

BACKGROUND

Over the last 15 years, there has been growing interest in the noble gas xenon as a new inhalational anesthetic. This is due to its favorable pharmacological properties such as short onset and offset, as well as its hemodynamic stability. However, most volatile anesthetics appear to play an important role in the multi-factorial etiology of perioperative liver injury by decreasing liver blood flow with a subsequent reduction of hepatic oxygen supply. However, the effects of the anesthetic gas xenon on hepatic perfusion and oxygenation have not been completely investigated.

METHODS

Following ethical approval, 18 anesthetized and acutely monitored pigs were randomly assigned to the two following groups: 9 animals received xenon anesthesia in increasing inspiratory concentrations of 0%, 20%, 50%, and 65% in addition to their basic intravenous anesthesia; 9 animals served as a control group. Measurement points for systemic and regional hemodynamic and oxygenation parameters were performed 30 min after changing the xenon concentration.

RESULTS

Xenon elicited dose-dependent systemic hemodynamic changes such that the mean arterial pressure did not change, while the heart rate and cardiac output decreased by about 30%, thereby indicating an increase in the systemic vascular resistance. Portal venous blood flow decreased, while hepatic arterial blood flow was unchanged. The oxygen supply of the liver was reduced, but not the rate of indocyanine plasma disappearance from the liver. Furthermore, the increase of liver surface pO2 to systemic hyperoxia was absent, and hepatic lactate uptake was reduced.

CONCLUSION

Xenon, in addition to basic intravenous anesthesia, elicited a decrease in heart rate and cardiac output and an increase in mean arterial pressure. Similar to volatile anesthetics, xenon does reduce portal venous flow and influences hepatic tissue oxygenation. In contrast, hepatic arterial blood flow remains stable in the presence of xenon, and no changes in the hepatic arterial buffer responses were evident. Xenon does affect hepatic perfusion and oxygenation.