Effects of chronic high fat diet on mediobasal hypothalamic satiety neuron function in POMC-Cre mice

OBJECTIVE

The prevalence of obesity has increased over the past three decades. Proopiomelanocortin (POMC) neurons in the hypothalamic arcuate nucleus (ARC) play a vital role in induction of satiety. Chronic consumption of high-fat diet is known to reduce hypothalamic neuronal sensitivity to hormones like leptin, thus contributing to the development and persistence of obesity. The functional and morphological effects of a high-calorie diet on POMC neurons and how these effects contribute to the development and maintenance of the obese phenotype are not fully understood. For this purpose, POMC-Cre transgenic mice model was exposed to high-fat diet (HFD) and at the end of a 3- and 6-month period, electrophysiological and morphological changes, and the role of POMC neurons in homeostatic nutrition and their response to leptin were thoroughly investigated.

METHODS

Effects of HFD on POMC-satiety neurons in transgenic mice models exposed to chronic high-fat diet were investigated using electrophysiological (patch-clamp), chemogenetic and Cre recombinase advanced technological methods. Leptin, glucose and lipid profiles were determined and analyzed.

RESULTS

In mice exposed to a high-fat diet for 6 months, no significant changes in POMC dendritic spine number or projection density from POMC neurons to the paraventricular hypothalamus (PVN), lateral hypothalamus (LH), and bed nucleus stria terminalis (BNST) were observed. It was revealed that leptin hormone did not change the electrophysiological activities of POMC neurons in mice fed with HFD for 6 months. In addition, chemogenetic stimulation of POMC neurons increased HFD consumption. In the 3-month HFD-fed group, POMC activation induced an orexigenic response in mice, whereas switching to a standard diet was found to abolish orexigenic behavior in POMC mice.

CONCLUSIONS

Chronic high fat consumption disrupts the regulation of POMC neuron activation by leptin. Altered POMC neuron activation abolished the neuron's characteristic behavioral anorexigenic response. Change in nutritional content contributes to the reorganization of developing maladaptations.

Postweaning Social Isolation Alters Puberty Onset by Suppressing Electrical Activity of Arcuate Kisspeptin Neurons

INTRODUCTION

Postweaning social isolation (PWSI) in rodents is an advanced psychosocial stress model in early life. Some psychosocial stress, such as restrain and isolation, disrupts reproductive physiology in young and adult periods. Mechanisms of early-life stress effects on central regulation of reproduction need to be elucidated. We have investigated the effects of PWSI on function of arcuate kisspeptin (ARCKISS1) neurons by using electrophysiological techniques combining with monitoring of puberty onset and estrous cycle in male and female Kiss1-Cre mice.

METHODS

Female mice were monitored for puberty onset with vaginal opening examination during social isolation. After isolation, the estrous cycle of female mice was monitored with vaginal cytology. Anxiety-like behavior of mice was determined by an elevated plus maze test. Effects of PWSI on electrophysiology of ARCKISS1 neurons were investigated by the patch clamp method after intracranial injection of AAV-GFP virus into arcuate nucleus of Kiss1-Cre mice after the isolation period.

RESULTS

We found that both male and female isolated mice showed anxiety-like behavior. PWSI caused delay in vaginal opening and extension in estrous cycle length. Spontaneous-firing rates of ARCKISS1 neurons were significantly lower in the isolated male and female mice. The peak amplitude of inhibitory postsynaptic currents to ARCKISS1 neurons was higher in the isolated mice, while frequency of excitatory postsynaptic currents was higher in group-housed mice.

CONCLUSION

These findings demonstrate that PWSI alters pre- and postpubertal reproductive physiology through metabolic and electrophysiological pathways.

Opioidergic signaling contributes to food-mediated suppression of AgRP neurons

Opioids are generally known to promote hedonic food consumption. Although much of the existing evidence is primarily based on studies of the mesolimbic pathway, endogenous opioids and their receptors are widely expressed in hypothalamic appetite circuits as well; however, their role in homeostatic feeding remains unclear. Using a fluorescent opioid sensor, deltaLight, here we report that mediobasal hypothalamic opioid levels increase by feeding, which directly and indirectly inhibits agouti-related protein (AgRP)-expressing neurons through the μ-opioid receptor (MOR). AgRP-specific MOR expression increases by energy surfeit and contributes to opioid-induced suppression of appetite. Conversely, its antagonists diminish suppression of AgRP neuron activity by food and satiety hormones. Mice with AgRP neuron-specific ablation of MOR expression have increased fat preference without increased motivation. These results suggest that post-ingestion release of endogenous opioids contributes to AgRP neuron inhibition to shape food choice through MOR signaling.

AgRP neurons encode circadian feeding time

Food intake follows a predictable daily pattern and synchronizes metabolic rhythms. Neurons expressing agouti-related protein (AgRP) read out physiological energetic state and elicit feeding, but the regulation of these neurons across daily timescales is poorly understood. Using a combination of neuron dynamics measurements and timed optogenetic activation in mice, we show that daily AgRP-neuron activity was not fully consistent with existing models of homeostatic regulation. Instead of operating as a 'deprivation counter', AgRP-neuron activity primarily followed the circadian rest-activity cycle through a process that required an intact suprachiasmatic nucleus and synchronization by light. Imposing novel feeding patterns through time-restricted food access or periodic AgRP-neuron stimulation was sufficient to resynchronize the daily AgRP-neuron activity rhythm and drive anticipatory-like behavior through a process that required DMHPDYN neurons. These results indicate that AgRP neurons integrate time-of-day information of past feeding experience with current metabolic needs to predict circadian feeding time.

Adrenergic modulation of melanocortin pathway by hunger signals

Norepinephrine (NE) is a well-known appetite regulator, and the nor/adrenergic system is targeted by several anti-obesity drugs. To better understand the circuitry underlying adrenergic appetite control, here we investigated the paraventricular hypothalamic nucleus (PVN), a key brain region that integrates energy signals and receives dense nor/adrenergic input, using a mouse model. We found that PVN NE level increases with signals of energy deficit and decreases with food access. This pattern is recapitulated by the innervating catecholaminergic axon terminals originating from NTSTH-neurons. Optogenetic activation of rostral-NTSTH → PVN projection elicited strong motivation to eat comparable to overnight fasting whereas its inhibition attenuated both fasting-induced & hypoglycemic feeding. We found that NTSTH-axons functionally targeted PVNMC4R-neurons by predominantly inhibiting them, in part, through α1-AR mediated potentiation of GABA release from ARCAgRP presynaptic terminals. Furthermore, glucoprivation suppressed PVNMC4R activity, which was required for hypoglycemic feeding response. These results define an ascending nor/adrenergic circuit, NTSTH → PVNMC4R, that conveys peripheral hunger signals to melanocortin pathway.

Angiotensin AT1A receptor signal switching in Agouti-related peptide neurons mediates metabolic rate adaptation during obesity

Resting metabolic rate (RMR) adaptation occurs during obesity and is hypothesized to contribute to failed weight management. Angiotensin II (Ang-II) type 1 (AT1A) receptors in Agouti-related peptide (AgRP) neurons contribute to the integrative control of RMR, and deletion of AT1A from AgRP neurons causes RMR adaptation. Extracellular patch-clamp recordings identify distinct cellular responses of individual AgRP neurons from lean mice to Ang-II: no response, inhibition via AT1A and Gαi, or stimulation via Ang-II type 2 (AT2) receptors and Gαq. Following diet-induced obesity, a subset of Ang-II/AT1A-inhibited AgRP neurons undergo a spontaneous G-protein "signal switch," whereby AT1A stop inhibiting the cell via Gαi and instead begin stimulating the cell via Gαq. DREADD-mediated activation of Gαi, but not Gαq, in AT1A-expressing AgRP cells stimulates RMR in lean and obese mice. Thus, loss of AT1A-Gαi coupling within the AT1A-expressing AgRP neuron subtype represents a molecular mechanism contributing to RMR adaptation.

Effects of endocrine disruptors on the electrical activity of leptin receptor neurons in the dorsomedial hypothalamus and anxiety-like behavior in male mice

There is increasing concern about the effects of endocrine disrupting chemicals (EDCs) on human health. Recently, some EDCs are suggested to affect energy metabolism leading to increased risk of obesity. Obesogenic effects of some EDCs on adipogenesis have been reported, however, there is no study examining their potential actions on the brain circuits controlling feeding and metabolism. We have investigated effects of tributyltin (TBT) and dichlorodiphenyltrichloroethane (p,p'-DDT) on electrical activity on dorsomedial hypothalamic leptin receptor neurons (DMH^LepR), morphological adaptations in neuronal anatomy of DMH^LepR, locomotion, and anxiety-like behaviors in mice. Twenty-three Lep-Cre transgenic mice were intracranially injected with GFP virus. Control animals received intraperitoneal corn oil alone while group 2 and 3 received TBT (25 μg/kg) and p,p'-DDT (2 mg/kg) for one month. Locomotor activity and anxiety-like behavior of the animals were determined by open field test. Electrophysiological effects of TBT and p,p'-DDT on DMH^LepR neurons were determined by patch clamp method. Neuronal anatomy was determined by confocal microscopy. Spontaneous firing frequency of DMH^LepR neurons of TBT group of mice was significantly higher than both p,p'-DDT and control groups (p < 0.01). TBT and p,p'-DDT significantly decreased frequency of the spontaneous inhibitory post-synaptic currents to DMH^LepR neurons compared to the control group (p < 0.05). The time spent in the center and the number of entrances to the center by the TBT-administered mice were significantly lower than other groups (p < 0.01). The total distance traveled and mean speed of the control group of mice were significantly higher than the p,p'-DDT- and TBT-administered animals (p < 0.0001). c-Fos activity of the p,p'-DDT- and TBT-administered animals were significantly elevated compared to the control group (p < 0.001), while no change in the number of dendritic spines were observed. In conclusion, this study demonstrates that exposure to TBT and p,p'-DDT alters electrical activity in DMH^LepR neurons and behavioral state in mice.

Dorsal raphe serotonergic neurons suppress feeding through redundant forebrain circuits

OBJECTIVE

Serotonin (5HT) is a well-known anorexigenic molecule, and 5HT neurons of dorsal raphe nucleus (DRN) have been implicated in suppression of feeding; however, the downstream circuitry is poorly understood. Here we explored major projections of DRN^5HT neurons for their capacity to modulate feeding.

METHODS

We used optogenetics to selectively activate DRN^5HT axonal projections in hypothalamic and extrahypothalamic areas and monitored food intake. We next used fiber photometry to image the activity dynamics of DRN^5HT axons and 5HT levels in projection areas in response feeding and metabolic hormones. Finally, we used electrophysiology to determine how DRN^5HT axons affect downstream neuron activity.

RESULTS

We found that selective activation of DRN^5HT axons in (DRN^5HT → LH) and (DRN^5HT → BNST) suppresses feeding whereas activating medial hypothalamic projections has no effect. Using in vivo imaging, we found that food access and satiety hormones activate DRN^5HT projections to LH where they also rapidly increase extracellular 5HT levels. Optogenetic mapping revealed that DRN^5HT → LH^vGAT and DRN^5HT → LH^vGlut2 connections are primarily inhibitory and excitatory respectively. Further, in addition to its direct action on LH neurons, we found that 5HT suppresses GABA release from presynaptic terminals arriving from AgRP neurons.

CONCLUSIONS

These findings define functionally redundant forebrain circuits through which DRN^5HT neurons suppress feeding and reveal that these projections can be modulated by metabolic hormones.

Cardiovascular risk factors: The effects of ageing and smoking on the immune system, an observational clinical study

Currently immunomodulatory compounds are under investigation for use in patients with cardiovascular disease, caused by atherosclerosis. These trials, using recurrent cardiovascular events as endpoint, require enrollment of large patient groups. We investigated the effect of key risk factors for atherosclerosis development, ageing and smoking, on the immune system, with the objective to identify biomarkers differentiating between human populations, and potentially serving as endpoints for future phase 1B trials with immunomodulatory compounds. Blood was collected from young healthy volunteers (aged 18-25 years, n=30), young smokers (18-25 years, n=20), elderly healthy volunteers (>60 years, n=20), heavy smokers (>45 years, 15 packyears, n=11) and patients with stable coronary artery disease (CAD) (>60 years, n=27). Circulating immune cell subsets were characterized by flow cytometry, and collected plasma was evaluated by proteomics (Olink). Clear ageing effects were observed, mostly illustrated by a lower level in CD8⁺ and naïve CD4⁺ and CD8⁺ T cells, with an increase in CD4⁺ and CD8⁺ effector memory T cells in elderly healthy volunteers compared to young healthy volunteers. Heavy smokers showed a more inflammatory cellular phenotype, especially a shift in Th1/Th2 ratio: higher Th1 and lower Th2 percentages compared to young healthy volunteers. A significant decrease in circulating atheroprotective oxLDL-specific IgM was found in patients with CAD compared to young healthy volunteers. Elevated pro-inflammatory and chemotactic proteins TREM1 and CCL11 were observed in elderly volunteers compared to young volunteers. In addition, heavy smokers had an increase in pro-inflammatory cytokine IL-6 and lysosomal protein LAMP3. These data show that ageing and smoking are associated with an inflammatory immunophenotype, and that heavy smokers or aged individuals may serve as potential populations for future clinical trials investigating immunomodulatory drugs targeted for cardiovascular disease.

FGF21 suppresses alcohol consumption through an amygdalo-striatal circuit

Excessive alcohol consumption is a major health and social issue in our society. Pharmacologic administration of the endocrine hormone fibroblast growth factor 21 (FGF21) suppresses alcohol consumption through actions in the brain in rodents, and genome-wide association studies have identified single nucleotide polymorphisms in genes involved with FGF21 signaling as being associated with increased alcohol consumption in humans. However, the neural circuit(s) through which FGF21 signals to suppress alcohol consumption are unknown, as are its effects on alcohol consumption in higher organisms. Here, we demonstrate that administration of an FGF21 analog to alcohol-preferring non-human primates reduces alcohol intake by 50%. Further, we reveal that FGF21 suppresses alcohol consumption through a projection-specific subpopulation of KLB-expressing neurons in the basolateral amygdala. Our results illustrate how FGF21 suppresses alcohol consumption through a specific population of neurons in the brain and demonstrate its therapeutic potential in non-human primate models of excessive alcohol consumption.

Towards remote monitoring in pediatric care and clinical trials-Tolerability, repeatability and reference values of candidate digital endpoints derived from physical activity, heart rate and sleep in healthy children

Background

Digital devices and wearables allow for the measurement of a wide range of health-related parameters in a non-invasive manner, which may be particularly valuable in pediatrics. Incorporation of such parameters in clinical trials or care as digital endpoint could reduce the burden for children and their parents but requires clinical validation in the target population. This study aims to determine the tolerability, repeatability, and reference values of novel digital endpoints in healthy children.

Methods

Apparently healthy children (n = 175, 46% male) aged 2–16 were included. Subjects were monitored for 21 days using a home-monitoring platform with several devices (smartwatch, spirometer, thermometer, blood pressure monitor, scales). Endpoints were analyzed with a mixed effects model, assessing variables that explained within- and between-subject variability. Endpoints based on physical activity, heart rate, and sleep-related parameters were included in the analysis. For physical-activity-related endpoints, a sample size needed to detect a 15% increase was calculated.

Findings

Median compliance was 94%. Variability in each physical activity-related candidate endpoint was explained by age, sex, watch wear time, rain duration per day, average ambient temperature, and population density of the city of residence. Estimated sample sizes for candidate endpoints ranged from 33–110 per group. Daytime heart rate, nocturnal heart rate and sleep duration decreased as a function of age and were comparable to reference values published in the literature.

Conclusions

Wearable- and portable devices are tolerable for pediatric subjects. The raw data, models and reference values presented here can be used to guide further validation and, in the future, clinical trial designs involving the included measures.

FGF21 Signals to Glutamatergic Neurons in the Ventromedial Hypothalamus to Suppress Carbohydrate Intake

Fibroblast growth factor 21 (FGF21) is an endocrine hormone produced by the liver that regulates nutrient and metabolic homeostasis. FGF21 production is increased in response to macronutrient imbalance and signals to the brain to suppress sugar intake and sweet-taste preference. However, the central targets mediating these effects have been unclear. Here, we identify FGF21 target cells in the hypothalamus and reveal that FGF21 signaling to glutamatergic neurons is both necessary and sufficient to mediate FGF21-induced sugar suppression and sweet-taste preference. Moreover, we show that FGF21 acts directly in the ventromedial hypothalamus (VMH) to specifically regulate sucrose intake, but not non-nutritive sweet-taste preference, body weight, or energy expenditure. Finally, our data demonstrate that FGF21 affects neuronal activity by increasing activation and excitability of neurons in the VMH. Thus, FGF21 signaling to glutamatergic neurons in the VMH is an important component of the neurocircuitry that functions to regulate sucrose intake.

NTS Catecholamine Neurons Mediate Hypoglycemic Hunger via Medial Hypothalamic Feeding Pathways

Glucose is the essential energy source for the brain, whose deficit, triggered by energy deprivation or therapeutic agents, can be fatal. Increased appetite is the key behavioral defense against hypoglycemia; however, the central pathways involved are not well understood. Here, we describe a glucoprivic feeding pathway by tyrosine hydroxylase (TH)-expressing neurons from nucleus of solitary tract (NTS), which project densely to the hypothalamus and elicit feeding through bidirectional adrenergic modulation of agouti-related peptide (AgRP)- and proopiomelanocortin (POMC)-expressing neurons. Acute chemogenetic inhibition of arcuate nucleus (ARC)-projecting NTS^TH neurons or their target, AgRP neurons, impaired glucoprivic feeding induced by 2-Deoxy-D-glucose (2DG) injection. Neuroanatomical tracing results suggested that ARC-projecting orexigenic NTS^TH neurons are largely distinct from neighboring catecholamine neurons projecting to parabrachial nucleus (PBN) that promotes satiety. Collectively, we describe a circuit organization in which an ascending pathway from brainstem stimulates appetite through key hunger neurons in the hypothalamus in response to hypoglycemia.

MCH Neuron Activity Is Sufficient for Reward and Reinforces Feeding

BACKGROUND

Melanin-concentrating hormone (MCH)-expressing neurons have been implicated in regulation of energy homeostasis and reward, yet the role of their electrical activity in short-term appetite and reward modulation has not been fully understood.

OBJECTIVES

We investigated short-term behavioral and physiological effects of MCH neuron activity manipulations.

METHODS

We used optogenetic and chemogenetic approaches in Pmch-cre transgenic mice to acutely stimulate/inhibit MCH neuronal activity while probing feeding, locomotor activity, anxiety-like behaviors, glucose homeostasis, and reward.

RESULTS

MCH neuron activity is neither required nor sufficient for short-term appetite unless stimulation is temporally paired with consumption. MCH neuronal activation does not affect short-term locomotor activity, but inhibition improves glucose tolerance and is mildly anxiolytic. Finally, using two different operant tasks, we showed that activation of MCH neurons alone is sufficient to induce reward.

CONCLUSIONS

Our results confirm diverse behavioral/physiological functions of MCH neurons and suggest a direct role in reward function.

Inactivation of Magel2 suppresses oxytocin neurons through synaptic excitation-inhibition imbalance

Prader-Willi and the related Schaaf-Yang Syndromes (PWS/SYS) are rare neurodevelopmental disorders characterized by overlapping phenotypes of high incidence of autism spectrum disorders (ASD) and neonatal feeding difficulties. Based on clinical and basic studies, oxytocin pathway defects are suggested to contribute disease pathogenesis but the mechanism has been poorly understood. Specifically, whether the impairment in oxytocin system is limited to neuropeptide levels and how the functional properties of broader oxytocin neuron circuits affected in PWS/SYS have not been addressed. Using cell type specific electrophysiology, we investigated basic synaptic and cell autonomous properties of oxytocin neurons in the absence of MAGEL2; a hypothalamus enriched ubiquitin ligase regulator that is inactivated in both syndromes. We observed significant suppression of overall ex vivo oxytocin neuron activity, which was largely contributed by altered synaptic input profile; with reduced excitatory and increased inhibitory currents. Our results suggest that dysregulation of oxytocin system goes beyond altered neuropeptide expression and synaptic excitation inhibition imbalance impairs overall oxytocin pathway function.

Treatment of industrial estate wastewater by the application of electrocoagulation process using iron electrodes

In this study electrocoagulation (EC) of industrial estate wastewater taken from the inlet of wastewater treatment plant was investigated using sacrificial iron electrodes. Employing a pole changer to homogenous consumption of electrodes, studies on the parameters such as current density, supporting electrolyte concentration and initial pH, which have significant effects on COD removal and hence the energy consumption, were performed. Hydrogen peroxide was used in different concentrations to observe its effects on COD removal efficiency and the energy consumption. Sludge productions were also calculated for all experiments. COD removal efficiency of ∼92% was obtained at the best experimental conditions (i = 30 mA/cm², SE = 3 mM Na₂SO₄, pH = original pH (∼6) of the wastewater, 1500 mg/L H₂O₂) with an energy cost of €3.41/m³ wastewater treated and the sludge production of 5.45 g per g COD removed.

Disturbed endometrial NF-κB expression in women with recurrent implantation failure

OBJECTIVE

This study was planned to investigate whether expression levels of endometrial NF-κB1 and NFκB p65 changes in women with recurrent implantation failure (RIF).

PATIENTS AND METHODS

The study group consists of 30 RIF patients having at least three previous failed IVF cycles. The control group comprises of 30 patients having one or no previous failed attempt. Endometrial samples were obtained from all participants during hysteroscopy at the late follicular phase. Samples underwent ELISA analysis and immunohistochemical staining. The semi-quantitative H-Score method was used for analyzing the intensity of endometrial NF-κB p65 expression.

RESULTS

The concentrations of endometrial NF-κB1 were found to be significantly increased when compared to control subjects. Likewise, significantly increased NF-κB p65 immunoreactivity was detected in the cytoplasm of luminal and glandular epithelial cells. The H-Score of NF-κB p65 in RIF women was found to be significantly increased when compared to control group.

CONCLUSIONS

Increased levels of NF-κB1 and NF-κB p65 in the endometrium of RIF women can disturb physiological inflammation which is known to be positive modulator of endometrial receptivity.

The role of S100B protein, neuron-specific enolase, and glial fibrillary acidic protein in the evaluation of hypoxic brain injury in acute carbon monoxide poisoning

The main purpose of this study was to assess the role of S100B protein, neuron-specific enolase (NSE), and glial fibrillary acidic protein (GFAP) in the evaluation of hypoxic brain injury in acute carbon monoxide (CO)-poisoned patients. This cross-sectional study was conducted among the patients with acute CO poisoning who referred to the emergency department in a 1-year period. Serum levels of S100B protein, NSE, and GFAP were determined on admission. A total of 55 CO-poisoned patients (mean age ± standard deviation, 45 ± 20.3 years; 60% women) were included in the study. The control group consisted of 25 healthy adults. The patients were divided into two groups according to whether they were conscious or unconscious. The serum levels of S100B, NSE, and GFAP were higher in patients than that in the control group. There was no significant difference between unconscious and conscious patients with respect to these markers. There was a statistically significant difference between the conscious and unconscious patients and the control group in terms of S100B and NSE levels. There was also a statistically significant difference between the unconscious patients and the control group in terms of GFAP levels. Increased serum S100B, NSE, and GFAP levels are associated with acute CO poisoning. These biomarkers can be useful in assessing the clinical status of patients with CO poisoning.

Therapeutic effect of magnesium sulphate on carbon monoxide toxicity-mediated brain lipid peroxidation

BACKGROUND

Carbon monoxide (CO) toxicity primarily results from cellular hypoxia caused by impedance of oxygen delivery. Studies show that CO may cause brain lipid peroxidation and leukocyte-mediated inflammatory changes in the brain.

AIM

The aim of this study was to investigate whether magnesium sulphate could prevent or diminish brain lipid peroxidation caused by carbon monoxide toxicity in rats.

MATERIALS AND METHODS

Fourty rats were divided into five groups of 8 rats each. Group l was not received any agent during the experiment. Group 2 was inhaled CO gas followed by intraperitoneally normal saline 30 minutes (min) later. Group 3 was inhaled CO gas followed by 100 mg/kg magnesium sulphate intraperitoneally 30 min later. Group 2 and Group 3 rats was undergone laparotomy and craniotomy while still under anesthesia at 6 hour, and tissue sample was obtained from the cerebrum. Group 4 was inhaled CO gas followed by intraperitoneally normal saline 30 min later. Group 5 was inhaled CO gas followed by 100 mg/kg magnesium sulphate intraperitoneally 30 min later. Group 4 and Group 5 rats was undergone laparotomy and craniotomy while still under anesthesia at 24 hour, and tissue sample was obtained from the cerebrum.

RESULTS

Nitric oxide levels were no significantly different between all groups. Malonyldialdehyde levels increased in intoxication group (group 2) and decreased in treatment group (group 3). Activities of superoxide dismutase decreased in intoxication group (group 2) and increased in treatment group (group 3). Activities of catalase increased in intoxication group (group 2) and decreased in treatment group (group 3). Activities of glutathione peroxidase (GSH-Px) decreased in intoxication group (group 4) and increased in treatment group (group 5).

CONCLUSIONS

CO poisoning caused significant damage, detected within the first 6 hours. Due to antioxidant enzymes, especially GSH-Px activity reaching the top level within 24th hours, significant oxidative damage was not observed. The protective effect against oxidative damage of magnesium sulfate has been identified within the first 6 hours.

Hypothalamic obesity in children

Hypothalamic obesity is an intractable form of obesity syndrome that was initially described in patients with hypothalamic tumours and surgical damage. However, this definition is now expanded to include obesity developing after a variety of insults, including intracranial infections, infiltrations, trauma, vascular problems and hydrocephalus, in addition to acquired or congenital functional defects in central energy homeostasis in children with the so-called common obesity. The pathogenetic mechanisms underlying hypothalamic obesity are complex and multifactorial. Weight gain results from damage to the ventromedial hypothalamus, which leads, variously, to hyperphagia, a low-resting metabolic rate; autonomic imbalance; growth hormone-, gonadotropins and thyroid-stimulating hormone deficiency; hypomobility; and insomnia. Hypothalamic obesity did not receive enough attention, as evidenced by rarity of studies in this group of patients. A satellite symposium was held during the European Congress of Obesity in May 2011, in Istanbul, Turkey, to discuss recent developments and concepts regarding pathophysiology and management of hypothalamic obesity in children. An international group of leading researchers presented certain aspects of the problem. This paper summarizes the highlights of this symposium. Understanding the central role of the hypothalamus in the regulation of feeding and energy metabolism will help us gain insights into the pathogenesis and management of common obesity.

Can exposure to manganese and extremely low frequency magnetic fields affect some important elements in the rat teeth?

BACKGROUND

Length and level of exposure to electromagnetic fields (EMFs) is increasing in association with the widespread use of electrical and electronic devices and technological progress. The undesirable effects of extremely low frequency magnetic fields (ELF-MFs) on health have attracted considerable interest.

MATERIALS AND METHODS

Sixty-four four-month-old male Wistar rats divided into eight groups of eight rats each were used. Seven groups were exposed to varying dosages of manganese (Mn) and a 50 Hz magnetic field (MF) of approximately 1 mT, while the last group was set aside as the cage control group and not subjected to any procedure. This study was intended to investigate the interactions between the application of MF and Mn and the elements Ca, Zn, Mg, and P thought to be involved in caries, in rat teeth.

RESULTS

Levels of Ca, Mg, Zn, and P in the experimental group rats were different to those in the control group.

CONCLUSIONS

The results demonstrate that ELF-MF and Mn can have significant effects on levels of elements in rat teeth. Further experimental and epidemiological studies of ELF-MF and Mn are needed in order to evaluate their dental effects.

Navigation in laparoscopy--prototype research platform for improved image-guided surgery

The manipulation of the surgical field in laparoscopic surgery, through small incisions with rigid instruments, reduces free sight, dexterity, and tactile feedback. To help overcome some of these drawbacks, we present a prototype research and development platform, CustusX, for navigation in minimally invasive therapy. The system can also be used for planning and follow-up studies. With this platform we can import and display a range of medical images, also real-time data such as ultrasound and X-ray, during surgery. Tracked surgical tools, such as pointers, video laparoscopes, graspers, and various probes, allow surgeons to interactively control the display of medical images during the procedure. This paper introduces navigation technologies and methods for laparoscopic therapy, and presents our software and hardware research platform. Furthermore, we illustrate the use of the system with examples from two pilots performed during laparoscopic therapy. We also present new developments that are currently being integrated into the system for future use in the operating room. Our initial results from pilot studies using this technology with preoperative images and guidance in the retroperitoneum during laparoscopy are promising. Finally, we shortly describe an ongoing multicenter study using this surgical navigation system platform.

Two cases of acute endosulfan toxicity

BACKGROUND

Endosulfan is widely used in insect control and is absorbed by both humans and animals through the intestinal tract, the lungs, and the skin. Organochlorine insecticides are highly toxic compounds that are responsible for a number of severe intoxications worldwide, with several deaths. A 9-year analysis by one of Turkey's poison control centers reported that pesticide intoxications accounted for 8.8% of 25,572 poisoning calls, with 80.3% of them relating to insecticides and 19.7% concerning rodenticides.

CASE REPORTS

We present two cases of unintentional exposure to endosulfan, one of which presented with neurological manifestations, liver toxicity, and required mechanical ventilation and emergent hemodialysis; the other had only neurological manifestations and liver toxicity.

CONCLUSION

In cases of endosulfan poisoning, physicians must be aware of neurological manifestations, seizures, and severe metabolic acidosis. If severe metabolic acidosis is present, we suggest that hemodialysis may be an important intervention and should be performed early.

The Prognostic Importance of Trauma Scoring Systems for Blunt Thoracic Trauma

BACKGROUND

Early identification and aggressive management of blunt thoracic trauma are essential to reduce the significant rates of morbidity and mortality. The aim of this study was to evaluate the independent predictive value of 5 different trauma scoring systems (Revised Trauma Score [RTS], Trauma and Injury Severity Score [TRISS], Injury Severity Score [ISS], Lung Injury Scale [LIS], and Chest Wall Injury Scale [CWIS]) with respect to prognostic factors such as tube thoracostomy duration, the need for mechanical support and thoracotomy, the length of hospital and ICU stay, morbid conditions, and deaths of patients with blunt thoracic trauma.

METHODS

The records of 152 patients with blunt thoracic trauma were reviewed and data consisting of the patients' age and gender, blood pressure and respiratory rate on admission, the extent of chest wall and intrathoracic injury, types of associated injuries, Glasgow Coma Scale (GCS) scores, the need for mechanical support and thoracotomy, tube thoracostomy duration, length of hospital and ICU stay, morbid conditions, and deaths were collected. The relations between the trauma scoring systems and prognostic factors were evaluated by multivariate analysis.

RESULTS

The analysis showed that only TRISS was an independent predictor of mortality and only LIS was an independent predictor of morbidity, the need for thoracotomy, and tube thoracostomy duration. TRISS and LIS were independent predictors of the length of ICU stay. ISS, CWIS, and LIS were independent predictors of the need for mechanical support. RTS, TRISS, ISS and LIS were independent predictors of the length of hospital stay.

CONCLUSIONS

The LIS grade appeared to correlate with the severity of blunt thoracic injury and was found to be the most useful scoring system in predicting the outcomes of these patients.

Ergonomic design criteria for a novel laparoscopic tool handle with tactile feedback

Laparoscopic surgery has many ergonomic disadvantages often not considered in the design of instruments. The poorly designed surgical tools produce inconveniences in both functional and cognitive aspects; including tactile sensation and visual-motor space coordination. The aim of this article is to find out how laparoscopic handle design can be improved by combining classical ergonomic guidelines with tactile feedback related to handle design. The article briefly discusses how the human hand and hand-held tools are used to perform tasks. An ergonomic handle for laparoscopic grasping, with a built-in tactile sensation display, is presented. Our review of laparoscopic instruments reveals important aspects for handle design. It is concluded that there is a need for greater awareness of ergonomic guidelines for users' sensory requirements when designing and manufacturing laparoscopic instruments.

Hemodynamic and tissue blood flow responses to long-term pneumoperitoneum and hypercapnia in the pig

BACKGROUND

Increased peritoneal blood flow may influence the ability of cancer cells to adhere to and survive on the peritoneal surface during and after laparoscopic cancer surgery. Carbon dioxide (CO2) pneumoperitoneum is associated with a marked blood flow increase in the peritoneum. However, it is not clear whether the vasodilatory effect in the peritoneum is related to a local or systemic effect of CO2.

METHODS

In this study, 21 pigs were exposed to pneumoperitoneum produced with either CO2 (n = 7) or helium (He) (n = 7) insufflation at 10 mmHg for 4 h, or to two consecutive levels of hypercapnia (7 and 11 kPa) (n = 7) produced by the addition of CO2 to the inhalational gas mixture. Tissue blood flow measurements were performed using the colored microsphere technique.

RESULTS

Blood flow in peritoneal tissue increased during CO2, but not He, pneumoperitoneum, whereas it did not change at any level of hypercapnia alone. There was no change in blood flow in most organs at the partial pressure of CO2 (PaCO2) level of 7 kPa. However, at a PaCO2 of 11 kPa, blood flow was increased in the central nervous system, myocardium, and some gastrointestinal organs. The blood flow decreased markedly in all striated muscular tissues during both levels of hypercapnia.

CONCLUSION

The effect of CO2 on peritoneal blood flow during laparoscopic surgery is a local effect, and not attributable to central hemodynamic effects of CO2 pneumoperitoneum or high systemic levels of CO2.

Development of a total colonoscopy rat model with endoscopic submucosal injection of the cecal wall

BACKGROUND

Experimental models of colorectal tumor require either laparotomy for induction or anastomosis following resection. The long murine cecum avoids the need for an anastomosis, making the cecum the preferred site for induction. This study aimed to evaluate total colonoscopy with submucosal injection of cecal wall (TCWI) in rats in terms of failure rate (FR), complication rate (CR), and reproducibility (R).

METHODS

A bolus of bowel prep was given. Anesthesia was injected intraperitoneally. A video fiberscope (5.9 mm outer diameter, 180/90 degrees up/down bending, 100/100 degrees right/left bending, 103 cm working length, 120 degrees view field, and 2.0 mm channel) allowed for irrigation and suction. Saline 1 ml was injected in the cecal wall through a 4-mm-long, 23-gauge needle placed on a 3-mm wire, resulting in a blister. FR was a failure to reach and inject the cecum. Rats were allowed to recover. CR was measured at necropsy. R was assessed by comparing TCWI time, FR, and CR for three investigators. Sample size of 120 (type I error, 0.05; power, 80%) was based on a pilot study. Data are presented as median (range).

RESULTS

A total of two of 122 rats (1.6%) died after prep or anesthesia. Bowel prep resulted in 99.1% evacuation of solid feces. A total of 120 male Sprague-Dawley retired breeders weighing 592 g (range, 349-780) underwent TCWI. Scope depth was 28 cm (range, 20-36). Irrigating fluid was 290 ml (range, 100-600). TCWI time was 7 min (range, 4-28). FR was 4%. In three failed cases, the scope reached the ascending colon. CR was 2%. There were two perforations in the ascending colon. All three operators had similar TCWI time (p = 0.673), FR (p > 0.1), and CR (p > 0.1). A total of 98.3% of rats survived to planned sacrifice. At 48-h necropsy, the injection site was macroscopically identified in 118 rats.

CONCLUSIONS

A safe and reproducible TCWI rat model has been achieved, which may provide a valuable tool in the future for studies of solid colorectal tumors.

Image-guided laparoscopic surgery. Review and current status

The main drawback with laparoscopic surgery is that the surgeon is unable to palpate vessels, tumours and organs during surgery. Further-more, the laparoscope only provides a surface view of organs. There is a need for more advanced visualizations techniques that can enhance the display presented to the surgeon so that important information below the surface of the organs is included when planning the procedure as well as for guidance and control during treatment. In this paper, we present a review of the literature and the state of art within image-guided laparoscopic surgery. We describe our own experience using a prototype navigation system for advanced visualizations and guidance during laparoscopic procedures in the retroperitoneum. Furthermore, we show sample images from the Future Operating Room for laparoscopic surgery in Trondheim, where this technology is being further developed and tested in clinical studies. Our system is based on three-dimensional navigation technology, i.e. preoperatively acquired magnetic resonance or computed tomography data used in combination with tracked instruments, allowing the surgeon to interactively control the display of images prior to and during surgery with normal use of the instruments. In summary, we believe that abdominal image navigation using tracked instruments and advanced visualizations has a large potential for improving future laparoscopic surgery, especially in cases where vessels and anatomical relations beyond surfaces is difficult to identify using only a laparoscope. The technology helps the surgeon to better understand the anatomy and locate blood vessels. Accordingly, we believe that this new technology could increase safety and make it easier for the surgeon to perform successful laparoscopic surgery.

Effect of interleukin-10 on pancreatic damage caused by organophosphate poisoning

Organophosphate poisoning is a common cause of severe morbidity and mortality in emergency departments. Acute pancreatitis is a frequently reported consequence of organophosphate poisoning, but preventing this potentially severe complication has not been the subject of much research. We tested whether interleukin-10, a cytoprotective agent, could prevent or diminish pathological signs of acute pancreatitis caused by organophosphate poisoning. Thirty rats were divided into three equal groups. Group 1 did not receive any agent during the experiment. Group 2 received 0.8 g/kg fenthion intraperitoneally, followed by 6 ml/kg intraperitoneal normal saline 30 min and 3 h later. Group 3 received 0.8 g/kg fenthion intraperitoneally, followed by 2 microg/kg of interleukin-10 intraperitoneally 30 min and 3 h later. All rats underwent laparotomy and thoracotomy while still under anesthesia at 6 h, and tissue samples were obtained from the pancreas. After blood samples were taken by cardiac puncture, the animals were sacrificed. Organophosphate poisoning resulted in significant elevations of serum amylase and glucose. Interleukin-10 significantly reduced pancreatic damage as determined by pathologic scoring, but not by enzyme elevations. Interleukin-10 should be considered for larger studies in other animal models to confirm its ability to decrease pancreatic damage after organophosphate poisoning treatment with interleukin-10.

Effect of carbon dioxide pneumoperitoneum on tissue blood flow in the peritoneum, rectus abdominis, and diaphragm muscles

BACKGROUND

Changes in local blood flow may play a role in the pathogenesis of port-site metastasis. This study aimed to investigate the effect of pneumoperitoneum induced by carbon dioxide (CO2) on the blood flow in the peritoneum and abdominal wall muscle layers, which are target structures for this phenomenon.

METHODS

The study was performed on domestic farm swine of both genders weighing 20 to 25 kg. Intraabdominal pressures (IAP) of 0, 5, and 10 mmHg were produced by either CO2 ( n = 9) or helium (He) ( n = 6) insufflations. The colored microsphere technique was used to measure blood flow distributions in the parietal peritoneum, rectus abdominis, and diaphragm muscles.

RESULTS

Insufflation of CO2 was associated with a threefold increase in blood flow of the parietal peritoneum at both 5 and 10 mmHg IAP ( p < 0.001 for both pressure levels). In contrast, insufflation of He caused a significant decrease in blood flow in the parietal peritoneum at both 5 and 10 mmHg ( p < 0.05). In the rectus abdominis and diaphragm muscles, blood flow remained unchanged after insufflation of CO2 at both 5 and 10 mmHg IAP. However, after insufflation of He, there was a substantial decrease in blood flow both in the rectus abdominis and diaphragm muscles at both 5 mmHg ( p < 0.01 and p < 0.05, respectively) and 10 mmHg ( p < 0.001 and p < 0.01, respectively).

CONCLUSIONS

Despite high intraabdominal pressure, tissues surrounding the abdominal cavity, particularly the peritoneum, respond to insufflation of CO2 with increased blood flow, which may favor the growth of tumor cells.

Electroadsorption of acilan blau dye from textile effluents by using activated carbon-perlite mixtures

The feasibility of the removal of dye stuffs from textile effluents by electroadsorption has been investigated. An activated carbon-perlite mixture with a ratio of 8:1 for bipolarity has been used as the adsorbent. Conventional adsorption experiments have also been conducted for comparison. A bipolar trickle reactor has been used in the electroadsorption experiments. The model wastewater has been prepared by using acilan blau dye. Initial dye concentration, bed height between the electrodes, applied potential, flowrate, and the supporting electrolyte concentration have been examined as the parameters affecting the removal efficiency. A local textile plant effluent has been treated in the optimum values of these parameters obtained from the experimental studies. Adsorption kinetics and the amount of adsorbent required to reach the maximum removal efficiency have also been investigated and mass-transfer coefficients have been calculated for adsorption and electroadsorption. The results showed that a removal efficiency of up to 100% can be achieved with energy consumption values of 1.58 kWh/m3 of wastewater treated. However, energy consumption decreases to 0.09 kWh/m3 if an exit dye concentration of 4.65 mg/L is accepted. It can be concluded from this work that this method combines all of the advantages of the activated-carbon adsorption and electrolytic methods for the removal of dyes from wastewater.

Technology and application of the reusable Olympus Ultrasonic Dissector

With US scalpels a new era of laparoscopic surgery has begun. We have given instances of the striking advantages of modern ultrasonic dissectors in general, and of the SonoSurg system in particular. Key aspects are reusability, modularity and multi-functionality. Modularity allows for extension of the basic scalpel e.g. to an aspirator, reusability results in cost effectiveness. Nevertheless, ultrasonically activated devices are not limited to the well-known scalpels and aspirators. New technologies such as the SonoSurg ultrasound trocar and combination instruments are currently under development.

Diagnostic value of serum cystatin C for evaluation of hepatorenal syndrome

BACKGROUND

The evaluation of renal function in patients with decompensated cirrhosis is important for prognosis, dosage assessment of potentially nephrotoxic drugs and recognition of changes in glomerular filtration rate (GFR) to decide paracentesis and diuretic therapy. Patients with many different disorders of hepatic function can present with various abnormalities of renal function in the absence of other known causes of renal failure which has been called hepatorenal syndrome (HRS). Some reports have pointed out that serum creatinine levels frequently failed to rise above normal levels even when glomerular filtration rate (GFR) is very low in cirrhotic patients with hepatorenal syndrome. The aim of this study was to determine if estimation of serum cystatin C could replace creatinine clearance in routine GFR determinations for patients with cirrhosis.

METHODS

Serum cystatin C, creatinine clearance (Clcr), and 99mTc-DTPA clearance were determined in 26 patients with cirrhosis. According to Child-Pugh's classification, 21 patients were in group C and 5 were in Group B.

RESULTS

Pearson correlation analyses showed that correlation between serum cystatin C and 99mTc-DTPA clearance was r=-0.522, p=0.006, between serum creatinine and 99mTc-DTPA was r=-0.373, p=0.06. The results of our study demonstrated that neither serum creatinine nor creatinine clearance (Clcr) were good indicators of hepatorenal syndrome because the mean value for Clcr was found to be higher than Tc-DTPA clearance, and there was no correlation between these two parameters (r=0.059). Additionally, the mean value of serum creatinine was found to be within the normal range, whereas the mean DTPA clearance level was lower than normal range.

CONCLUSIONS

This finding could be explained by the fact that cirrhotic patients with poor nutrition may have decreased protein intake, low muscle mass and lack of converting capacity of creatine to creatinine. Thus, we suggest that serum cystatin C assay, which has good analytical performance, could replace or at least be added to creatinine measurement for GFR assessment in patients with cirrhosis.

Effect of increased intraabdominal pressure on cardiac output and tissue blood flow assessed by color-labeled microspheres in the pig

BACKGROUND

Studies of the hemodynamic effects associated with the pneumoperitoneum have had controversial results. We set out to investigate the effect of increased intraabdominal pressure (IAP) on cardiac output and tissue blood flow in various intraabdominal and extraabdominal organs using the color-labeled microsphere (CLM) technique.

METHODS

IAP was induced by CO2 insufflation in anesthetized pigs; 0, 5, and 10 mmHg was used in the low-pressure group and 0, 15, and 24 mmHg in the high-pressure group. Tissue blood flow (ml.min-1.g-1) and cardiac output (CO) (ml/min) were determined by the CLM technique.

RESULTS

CO decreased at IAP > or = 15 mmHg. Arterial PaCO2 and hydrogen ion concentration increased in response to all levels of IAP. Arterial PaO2, oxygen saturation, and bicarbonate ion concentration remained unchanged. Low IAP did not influence tissue blood flows in most of the organs. However, in the spleen, pancreas, esophagus, and gastric mucosal specimens, tissue blood flow was significantly decreased at 24 mmHg.

CONCLUSION

The level of IAP used in current practice (10-12 mmHg) appears to be safe with regard to hemodynamic variables and tissues blood flow; however, higher levels may induce a decrease in cardiac output and tissue blood flow.

A comparative experimental study evaluating the performance of surgical robots aesop and endosista

The aim of this study was to experimentally assess and compare the accuracy of the surgical robots Aesop and Endosista as camera holders for use in laparoscopic surgery. The performance of these two robotic systems was examined for linear (upwards, downwards, diagonal), complex, and "in and out" movements using laparoscopic training boxes. Standard distances and tests were used for each system, and the time required to achieve each task was measured. The majority of the linear movements of the verbal and preprogrammed modes of Aesop were quicker than those of Endosista. Diagonal movements were significantly faster with the preprogrammed-mode Aesop. Complex or three-dimensional movements were also significantly faster with both modes of Aesop than with Endosista. Under the experimental conditions, Aesop, particularly in the preprogrammed mode, is quicker and more accurate than Endosista.

The effect of antioxidant therapy on colonic inflammation in the rat

Under normal physiological conditions, chemical and antioxidant defenses protect tissues from the damaging effects of reactive oxygen metabolites (ROM). It has been proposed that ROMs are involved in the development of tissue injury in many inflammatory diseases and also in patients with colitis. In the present study we aimed to investigate the effects of antioxidant therapy on the extent of colonic inflammation and ROM levels in the injured tissues in a trinitrobenzene sulfonic acid-induced colitis model in the rat. Sprague-Dawley rats were pretreated with the antioxidants superoxide dismutase (30,000 U/kg s.c.) or catalase (400,000 U/kg s.c.) prior to induction of colitis and they were decapitated 24 h (acute group) or 6 days (chronic group) after the induction of colitis (each group consists of eight to ten rats). Pretreatment with the antioxidants reduced the macroscopic damage score significantly in both acute and chronic groups compared with untreated colitis groups, whereas they reduced the microscopic damage score and colonic wet weight only in the chronic group. The chemiluminescence assay - a technique to assess the presence of reactive oxygen species in the tissues - values of the groups pretreated with the antioxidants showed a tendency to decrease compared with the untreated colitis group, but they were not statistically significant. Based on these findings, pretreatment with the antioxidants superoxide dismutase or catalase has beneficial effects on the extent of colonic inflammation, particularly in the chronic period, and this may support the importance of antioxidant therapy to reduce the severity of inflammatory bowel disease in humans.

Comparison of infertility rates in communities from boron-rich and boron-poor territories

As a part of a large-scale work aimed at studying the health effects of boron (B) in residents of a country with the world's largest supply, developmental effects of B are presented. Spontaneous abortions, stillbirths, and congenital malformations in addition to early infant mortality were questioned in the field by home visits. Although the number of families so far ascertained is rather small, the rates related to spontaneous abortions and stillbirths from high B exposure vs low B exposure subpopulations revealed no differences of significance, providing no evidence that B affects human development adversely.