Stress, acute hyperglycemia, and hyperlipidemia role of the autonomic nervous system and cytokines

The cancer-immune dialogue in the context of stress

Although there is little direct evidence supporting that stress affects cancer incidence, it does influence the evolution, dissemination and therapeutic outcomes of neoplasia, as shown in human epidemiological analyses and mouse models. The experience of and response to physiological and psychological stressors can trigger neurological and endocrine alterations, which subsequently influence malignant (stem) cells, stromal cells and immune cells in the tumour microenvironment, as well as systemic factors in the tumour macroenvironment. Importantly, stress-induced neuroendocrine changes that can regulate immune responses have been gradually uncovered. Numerous stress-associated immunomodulatory molecules (SAIMs) can reshape natural or therapy-induced antitumour responses by engaging their corresponding receptors on immune cells. Moreover, stress can cause systemic or local metabolic reprogramming and change the composition of the gastrointestinal microbiota which can indirectly modulate antitumour immunity. Here, we explore the complex circuitries that link stress to perturbations in the cancer-immune dialogue and their implications for therapeutic approaches to cancer.

Latent class analysis to evaluate performance of plasma cortisol, plasma catecholamines, and SHSQ-25 for early recognition of suboptimal health status

Background

Chronic stress is associated with suboptimal health status (SHS) which is a new public health challenge in China and worldwide. Plasma stress hormones may act as potential objective biomarkers for SHS measure. This study was aimed to evaluate the diagnostic performance of plasma cortisol, catecholamine adrenaline/noradrenaline, and SHS questionnaires (SHSQ) for SHS using latent class analysis (LCA) in the absence of a gold standard.

Methods

A cross-sectional study was conducted among 868 employees in Beijing. The SHS questionnaires-25 (SHSQ-25) was distributed, and plasma cortisol, adrenaline, and noradrenaline were measured in the survey. LCA was used to assess the performance of both subjective and objective measures for SHS recognition.

Results

Akaike information criterion (AIC) and consistent AIC (CAIC) was 14.11 and 54.48 respectively, indicating that the model was well fitted. The sensitivity and specificity of plasma cortisol were 0.836 (95% CI 0.811-0.861) and 0.840 (95% CI 0.816-0.864), respectively. The area under curve (AUC) of receiver operating characteristic (ROC) of SHSQ-25 was 0.743 (95% CI 0.709-777), while the AUC of plasma adrenaline was 0.688 (95% CI 0.651-0.725). The prevalence of SHS in the investigated population was 34.78%.

Conclusion

Plasma cortisol is a valuable biomarker for SHS detection, whereas SHSQ-25 is more suitable for SHS screening in the population-based health survey. The accuracy and applicability of plasma adrenaline are inferior to cortisol and SHSQ-25, respectively. LCA has merit to evaluate performance of plasma cortisol, catecholamines, and SHSQ-25 for recognition of SHS in the absence of a gold standard test.

Identification of Neuroendocrine Stress Response-Related Circulating MicroRNAs as Biomarkers for Type 2 Diabetes Mellitus and Insulin Resistance

BACKGROUND

Chronic stress plays an important role in the development of type 2 diabetes mellitus (T2DM) and insulin resistance (IR). MicroRNAs (miRNAs) play key roles in mediating stress responses by regulating the expression of target genes. This study systematically screened and identified the neuroendocrine stress response-related circulating miRNAs which are associated with T2DM and IR.

METHODS

Based on the differential plasma expression profiles between individuals with and without T2DM, stress-related miRNAs were selected from those differently expressed miRNAs whose targets are involved in known neuroendocrine pathway of stress response. Candidate miRNAs were further validated by quantitative real-time polymerase chain reaction in a large sample, including 112 T2DM patients, 72 individuals with impaired fasting glucose (IFG), and 94 healthy controls. The association between miRNA expression and potential risk of T2DM and IFG was assessed by multivariate logistic regression models. The miRNA predictors of IR were identified by stepwise multiple regression analysis. The diagnostic performance for T2DM was evaluated by area under the curve (AUC) of receiver operating characteristic (ROC).

RESULTS

let-7b, let-7i, miR-142, miR-144, miR-155, and miR-29a were selected as candidate miRNAs for validation. Increased expression of let-7b, miR-144, and miR-29a and decreased expression of miR-142 were significant independent predictors of T2DM, IFG, and IR (P < 0.0125). These miRNAs significantly correlated with stress hormone levels (P < 0.0125). A three-miRNA panel, including let-7b, miR-142, and miR-144 had a high accuracy for diagnosing T2DM (AUC = 0.871, 95% CI: 0.822-0.919).

CONCLUSION

let-7b, miR-142, miR-144, and miR-29a in plasma may be important markers of neuroendocrine stress response and may play a role in the pathogenesis of T2DM and IR.

Effect of pertussis toxin pretreated centrally on blood glucose level induced by stress

In the present study, we examined the effect of pertussis toxin (PTX) administered centrally in a variety of stress-induced blood glucose level. Mice were exposed to stress after the pretreatment of PTX (0.05 or 0.1 µg) i.c.v. or i.t. once for 6 days. Blood glucose level was measured at 0, 30, 60 and 120 min after stress stimulation. The blood glucose level was increased in all stress groups. The blood glucose level reached at maximum level after 30 min of stress stimulation and returned to a normal level after 2 h of stress stimulation in restraint stress, physical, and emotional stress groups. The blood glucose level induced by cold-water swimming stress was gradually increased up to 1 h and returned to the normal level. The intracerebroventricular (i.c.v.) or intrathecal (i.t.) pretreatment with PTX, a Gi inhibitor, alone produced a hypoglycemia and almost abolished the elevation of the blood level induced by stress stimulation. The central pretreatment with PTX caused a reduction of plasma insulin level, whereas plasma corticosterone level was further up-regulated in all stress models. Our results suggest that the hyperglycemia produced by physical stress, emotional stress, restraint stress, and the cold-water swimming stress appear to be mediated by activation of centrally located PTX-sensitive G proteins. The reduction of blood glucose level by PTX appears to due to the reduction of plasma insulin level. The reduction of blood glucose level by PTX was accompanied by the reduction of plasma insulin level. Plasma corticosterone level up-regulation by PTX in stress models may be due to a blood glucose homeostatic mechanism.

Losartan may prevent the elevation of plasma glucose, corticosterone and catecholamine levels induced by chronic stress

Introduction

Stress is a stimulus that activates the hypothalamic pituitary adrenal (HPA) axis and sympathetic nervous system (SNS). Increased activity of the SNS causes to increment or impairment in blood pressure, heart rate, body temperature and plasma glucose and adrenocorticotrophic hormone (ACTH) levels. Angiotensin II (Ang II), which is a product of the renin-angiotensin system (RAS), is an important factor affecting the activity of the SNS and responses to stress. We suggest that the blockade of Ang II may be worthwhile in the prevention and treatment of diabetes mellitus and cardiovascular diseases affected by stress. Therefore, we investigated the effects of immobilisation stress on blood glucose, norepinephrine (NE), epinephrine (E) and corticosterone levels and the effects of an Ang II receptor antagonist, losartan, on these parameters.

Materials and methods

The rats were kept in small cylindrical cages for 60 min/day for 10 consecutive days to perform chronic immobilisation stress. Losartan (10 mg/kg) was given daily by gavage to Losartan (L) and Losartan + Chronic Stress (L+CS) groups. Control (C) and Chronic Stress (CS) P groups received an equal volume of saline daily by gavage for 10 days. After the last stress regimen, blood samples were collected for plasma glucose, NE, E and corticosteroid measurements.

Results

Plasma glucose, NE, E and corticosterone levels in the CS Group increased significantly compared with the C group. In Group L+CS, the plasma glucose, NE, E and corticosterone levels decreased significantly vs. Group CS. In Group L there was no significant difference vs. Group C.

Conclusion

It can be speculated that chronic blockade of RAS may decrease the excess sympathetic responses to stress in cardiovascular diseases and prevent the likely development of Type II diabetes mellitus.

Catheter-based arterial sympathectomy: hypertension and beyond

Transluminal ablation of renal artery sympathetic nerves has been shown to provide a significant and durable reduction in blood pressure with very low complication rates. Additional publications have documented improvement in insulin sensitivity, obstructive sleep apnea indices, and frequency and severity of congestive heart failure in subgroups undergoing the procedure. This technology may provide effective management of other diseases in which there is autonomic imbalance. Available data are reviewed with the intent to provoke interest within the interventional radiology community in this novel technology, which may allow minimally invasive treatment of many important chronic medical conditions.

Deletion of GαZ protein protects against diet-induced glucose intolerance via expansion of β-cell mass

Insufficient plasma insulin levels caused by deficits in both pancreatic β-cell function and mass contribute to the pathogenesis of type 2 diabetes. This loss of insulin-producing capacity is termed β-cell decompensation. Our work is focused on defining the role(s) of guanine nucleotide-binding protein (G protein) signaling pathways in regulating β-cell decompensation. We have previously demonstrated that the α-subunit of the heterotrimeric G(z) protein, Gα(z), impairs insulin secretion by suppressing production of cAMP. Pancreatic islets from Gα(z)-null mice also exhibit constitutively increased cAMP production and augmented glucose-stimulated insulin secretion, suggesting that Gα(z) is a tonic inhibitor of adenylate cyclase, the enzyme responsible for the conversion of ATP to cAMP. In the present study, we show that mice genetically deficient for Gα(z) are protected from developing glucose intolerance when fed a high fat (45 kcal%) diet. In these mice, a robust increase in β-cell proliferation is correlated with significantly increased β-cell mass. Further, an endogenous Gα(z) signaling pathway, through circulating prostaglandin E activating the EP3 isoform of the E prostanoid receptor, appears to be up-regulated in insulin-resistant, glucose-intolerant mice. These results, along with those of our previous work, link signaling through Gα(z) to both major aspects of β-cell decompensation: insufficient β-cell function and mass.

Sequence variants of interleukin 6 (IL-6) are significantly associated with a decreased risk of late-onset Alzheimer's disease

BACKGROUND

Interleukin 6 (IL-6) has been related to beta-amyloid aggregation and the appearance of hyperphosphorylated tau in Alzheimer's disease (AD) brain. However, previous studies relating IL-6 genetic polymorphisms to AD included few and unrepresentative single nucleotide polymorphisms (SNPs) and the results were inconsistent.

METHODS

This is a case-control study. A total of 266 patients with AD, aged≧65, were recruited from three hospitals in Taiwan (2007-2010). Controls (n = 444) were recruited from routine health checkups and volunteers of the hospital during the same period of time. Three common IL-6 haplotype-tagging SNPs were selected to assess the association between IL-6 polymorphisms and the risk of late-onset AD (LOAD).

RESULTS

Variant carriers of IL-6 rs1800796 and rs1524107 were significantly associated with a reduced risk of LOAD [(GG + GC vs. CC): adjusted odds ratio (AOR) = 0.64 and (CC + CT vs. TT): AOR = 0.60, respectively]. Haplotype CAT was associated with a decreased risk of LOAD (0 and 1 copy vs. 2 copies: AOR = 0.65, 95% CI = 0.44-0.95). These associations remained significant in ApoE e4 non-carriers only. Hypertension significantly modified the association between rs2069837 polymorphisms and the risk of LOAD (pinteraction = 0.03).

CONCLUSIONS

IL-6 polymorphisms are associated with reduced risk of LOAD, especially in ApoE e4 non-carriers. This study identified genetic markers for predicting LOAD in ApoE e4 non-carriers.

The regulation of blood glucose level in physical and emotional stress models: possible involvement of adrenergic and glucocorticoid systems

This study was done to determine the effect of stress on blood glucose regulation in ICR mice. The stress was induced by the electrical foot shock-witness model. Blood glucose level was found to be increased in the electrical foot shock-induced physical stress group. Furthermore, the blood glucose levels were also elevated in the emotional stress group in both physical and emotional stress groups. The blood glucose level reached maximum 30 min after stress stimulation and returned to normal level 2 h after stress stimulation in both physical and emotional stress groups. Subsequently, we observed that intraperitoneal injection of phentolamine (an α1-adrenergic receptor antagonist), yohimbine (an α2-adrenergic receptor antagonist) or RU486 (a glucocorticoid receptor blocker) significantly inhibited blood glucose level induced by both physical and emotional stress. The results of our study suggest that physical and emotional stress increases blood glucose level via activation of adrenergic and glucocorticoid system.

Metyrapone blunts stress-induced hyperthermia and increased locomotor activity independently of glucocorticoids and neurosteroids

Metyrapone, a cytochrome P(450) inhibitor used to inhibit corticosterone synthesis, triggers biological markers of stress and also reduces stress-induced anxiety-like behaviors. To address these controversial effects, 6 separate investigations were carried out. In a first set of investigations, abdominal temperature (T(abd)), spontaneous locomotor activity (A(S)) and electroencephalogram (EEG) were recorded in freely moving rats treated with either saline or 150 mg kg(-1) metyrapone. An increase in T(abd) and A(S) occurred in saline rats, while, metyrapone rats exhibited an immediate decrease, both variables returning to basal values 5h later. Concomitantly, the EEG spectral power increased in the gamma and beta 2 bands and decreased in the alpha frequency band, and the EMG spectral power increased. This finding suggests that metyrapone depressed stress-induced physiological response while arousing the animal. In a second step, restraint stress was applied 5h after injection. Metyrapone significantly blunted the stress-induced T(abd) and A(S) rise, without affecting the brain c-fos mRNA increase. Corticosterone (5 and 40 mg kg(-1)) injected concomitantly to metyrapone failed to reverse the observed metyrapone-induced effects in T(abd) and A(S). Finasteride (50 mg kg(-1)), which blocks neurosteroid production, was also unable to block these effects. In conclusion, metyrapone acutely reduced stress-induced physiological response in freely behaving rats independently from glucocorticoids and neurosteroids.

Anti-stress effects of ginseng via down-regulation of tyrosine hydroxylase (TH) and dopamine β-hydroxylase (DBH) gene expression in immobilization-stressed rats and PC12 cells

Catecholamines are among the first molecules that displayed a kind of response to prolonged or repeated stress. It is well established that long-term stress leads to the induction of catecholamine biosynthetic enzymes such as tyrosine hydroxylase (TH) and dopamine β-hydroxylase (DBH) in adrenal medulla. The aim of the present study was to evaluate the effects of ginseng on TH and DBH mRNA expression. Repeated (2 h daily, 14 days) immobilization stress resulted in a significant increase of TH and DBH mRNA levels in rat adrenal medulla. However, ginseng treatment reversed the stress-induced increase of TH and DBH mRNA expression in the immobilization-stressed rats. Nicotine as a ligand of the nicotinic acetylcholine receptor (nAChR) in adrenal medulla stimulates catecholamine secretion and activates TH and DBH gene expression. Nicotine treatment increased mRNA levels of TH and DBH by 3.3- and 3.1-fold in PC12 cells. The ginseng total saponin exhibited a significant reversal in the nicotine-induced increase of TH and DBH mRNA expression, decreasing the mRNA levels of TH and DBH by 57.2% and 48.9%, respectively in PC12 cells. In conclusion, immobilization stress induced catecholamine biosynthetic enzymes gene expression, while ginseng appeared to restore homeostasis via suppression of TH and DBH gene expression. In part, the regulatory activity in the TH and DBH gene expression of ginseng may account for the anti-stress action produced by ginseng.

The role of hyperglycemia in burned patients: evidence-based studies

Severely burned patients typically experience a systemic response expressed as increased metabolism, inflammation, alteration of cardiac and immune function, and associated hyperglycemia. Hyperglycemia has been associated with an increased risk of morbidity and mortality in critically ill patients. Until recently and for many years, hyperglycemia has been expectantly managed and considered a normal and desired response of an organism to stress. However, findings reported from recent studies now suggest beneficial effects of intensive insulin treatment of critically ill patients. The literature on the management of hyperglycemia in severely burned patients is sparse, with most of the available studies involving only small numbers of burned patients. The purpose of this article is to describe the pathophysiology of hyperglycemia after severe burns and to review the available literature on the outcome of intensive insulin treatment and other anti-hyperglycemic modalities in burned patients in an evidence-based medical approach.

Association of glucocorticoid with stress-induced modulation of body temperature, blood glucose and innate immunity

To know the details of the mechanism on stress-associated responses, attention was first focused on body temperature and blood glucose after stress. Mice were exposed to restraint stress for 6 h. Under this condition, hypothermia (39 degrees C --> 33 degrees C) and hyperglycemia (150 mg/dl --> 350 mg/dl) were induced. Reflecting a stress-associated response, an increase of serum corticosterone (200 ng/ml --> up to 600 ng/ml) was observed. It was examined whether an administration of glucocorticoid induced a similar response. An injection of hydrocortisone (5.0 and 10.0 mg/mouse) simultaneously induced hypothermia and hyperglycemia. The effect on immunoparameters by an injection of hydrocortisone was examined. Although immunosuppression was seen as thymic atrophy and a decrease in the proportion of B cells in the liver, extrathymic T cells and NKT cells were found to be stress-resistant lymphocyte populations, especially in the liver. HSP70 mRNA was indicated to increase in the adrenal glands in response to the hydrocortisone injection. All these responses, including hypothermia, hyperglycemia and immunomodulation, induced by the hydrocortisone injection were suppressed by pre-administration of a glucocorticoid receptor antagonist (RU-486). These results suggest that glucocorticoid is one of the important mediators of the stress-associated responses.

Feeding high proportions of barley grain in a total mixed ration perturbs diurnal patterns of plasma metabolites in lactating dairy cows

The aim of this study was to evaluate effects of feeding increasing proportions of barley grain in a total mixed ration (TMR) on diurnal plasma metabolite fluctuations in high-producing dairy cows. Eight early- to mid-lactation (60 to 140 d in milk) primiparous Holstein cows were assigned to a double 4 x 4 Latin square experimental design. Each experimental period lasted 21 d with the first 11 d used for diet adaptation. Cows were fed a TMR once daily at 0800 h containing no barley grain (control diet), or 15, 30, and 45% (dry matter basis) barley grain as well as barley silage. Blood samples were collected from the tail vein on the last day of each period shortly before (i.e., 0 h) and at 2, 4, 6, 8, 10, and 12 h after the morning feeding. Concentrations of glucose, nonesterified fatty acids (NEFA), beta-hydroxybutyric acid, cholesterol, and lactate in plasma were measured. Results of this study showed that feeding increasing proportions of barley grain affected concentrations of glucose and lactate in plasma with greater plasma glucose and lactate in cows fed the highest amount of grain; however, the amount of grain in the diet did not have an effect on diurnal patterns of plasma glucose. Additionally, the concentration of NEFA in plasma was greater in cows fed the higher grain diets and was greater in the hours following the morning meal than later in the day. The amount of grain in the diet was associated with lower plasma beta-hydroxybutyric acid, which increased particularly after the morning meal. Interestingly, cows fed the most barley grain had the lowest plasma cholesterol and this decreased during the day. In conclusion, the concomitant increase of glucose, lactate, and NEFA as well as the decrease of plasma cholesterol in cows fed high proportions of barley grain suggest that high inclusion of barley grain in the diet played a role in the diurnal patterns of plasma metabolites in lactating dairy cows. However, further research is warranted to understand involvement of these metabolic changes on the long-term health and productivity of dairy cows.

Corticosterone inhibits the lipid-mobilizing effects of oleoyl-estrone in adrenalectomized rats

Oleoyl-estrone (OE) is an adipose-derived signal that decreases energy intake and body lipid, maintaining energy expenditure and glycemic homeostasis. Glucocorticoids protect body lipid and the metabolic status quo. We studied the combined effects of OE and corticosterone in adrenalectomized female rats: daily OE gavages (0 or 10 nmol/g) and slow-release corticosterone pellets at four doses (0, 0.5, 1.7, and 4.8 mg/d). Intact and sham-operated controls were also included. After 8 d, body composition and plasma metabolites and hormones were measured. OE induced a massive lipid mobilization (in parallel with decreased food intake and maintained energy expenditure). Corticosterone increased fat deposition and inhibited the OE-elicited mobilization of body energy, even at the lowest dose. OE enhanced the corticosterone-induced rise in plasma triacylglycerols, and corticosterone blocked the OE-induced decrease in leptin. High corticosterone and OE increased insulin resistance beyond the effects of corticosterone alone. The presence of corticosterone dramatically affected OE effects, reversing its decrease of body energy (lipid) content, with little or no change on food intake or energy expenditure. The maintenance of glycemia and increasing insulin in parallel to the dose of corticosterone indicate a decrease in insulin sensitivity, which is enhanced by OE. The reversal of OE effects on lipid handling, insulin resistance, can be the consequence of a corticosterone-induced OE resistance. Nevertheless, OE effects on cholesterol were largely unaffected. In conclusion, corticosterone administration effectively blocked OE effects on body lipid and energy balance as well as insulin sensitivity and glycemia.

Milnacipran, a serotonin and norepinephrine reuptake inhibitor, induces appetite-suppressing effects without inducing hypothalamic stress responses in mice

Milnacipran, a selective serotonin (5-HT) and norepinephrine (NE) reuptake inhibitor, increases extracellular 5-HT and NA levels equally in the central nervous system. Here, we report that systemic administration of milnacipran (20–60 mg/kg) significantly suppressed food intake after fasting in C57BL6J mice. The appetite-suppressing effects of milnacipran were sustained for 5 h. Neither SB242084, a selective 5-HT2C receptor antagonist, nor SB224289, a selective 5-HT1B receptor antagonist, reversed the appetite-suppressing effects of milnacipran. Milnacipran suppressed food intake and body weight in wild-type mice and in Ay mice, which have ectopic expression of the agouti protein. Moreover, milnacipran significantly increased hypothalamic proopiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) mRNA levels, while having no effect on hypothalamic neuropeptide Y, ghrelin, corticotropin-releasing hormone (CRH), and suppressor of cytokine signaling-3 mRNA levels. Interestingly, milnacipran did not increase plasma corticosterone and blood glucose levels, whereas fenfluramine, which inhibits 5-HT reuptake and stimulates 5-HT release, significantly increased plasma corticosterone and blood glucose levels in association with increased hypothalamic CRH mRNA levels. The appetite-suppressing effects of milnacipran had no effects on food intake in food-restricted, wild-type mice and Ay mice. On the other hand, fenfluramine suppressed food intake in food-restricted wild-type mice, but it had no effects in food-restricted Ay mice. These results suggest that inhibition of 5-HT and NA reuptake induces appetite-suppressing effects independent of 5-HT2C and 5-HT1B receptors, and increases hypothalamic POMC and CART gene expression without increasing plasma corticosterone and blood glucose levels in mice.

The effects of acute stress and pubertal development on metabolic hormones in the rat

A dramatic change in stress responsiveness occurs during pubertal development such that stress-induced corticosterone secretion in prepubertal animals takes 45-60 min longer to return to baseline compared to adults. Though corticosterone is known to influence energy mobilization, it is presently unknown whether stressors affect other hormones important in energy utilization and metabolism differentially in animals before and after pubertal development. Therefore, we exposed prepubertal (28 days of age) and adult (77 days of age) male rats to a single 30 min session of restraint stress in either the light or dark phase of the animals' light-dark (LD) cycle and measured plasma glucose, insulin and thyroid hormones (thyroxine (T4) and triiodothyronine (T3)). We found similar stress-induced increases in plasma glucose levels in prepubertal and adult animals in the LD phase of the LD cycle. We also found that prepubertal animals have lower circulating insulin and total and free T4 levels, but higher total and free T3 levels compared to adults in both the light and dark phases (LD). Interestingly, insulin and thyroid hormone levels were unaffected by acute stress at either age or time of day. These data indicate that, despite prepubertal animals showing an extended glucocorticoid stress response after a single acute exposure to stress, glucose levels are similarly affected by acute stress in prepubertal and adult animals. Furthermore, though stage of development significantly affects the levels of peripheral metabolic hormones such as insulin, T4 and T3, acute stress does not appreciably influence their secretion before or after puberty.

Lipid kinetics in obese patients undergoing laparoscopy. the impact of cortisol inhibition by etomidate

The aim of this study was to investigate the response of cortisol, insulin and lipid parameters [serum Lipoprotein Lipase activity, choleseryl-ester transfer protein, triglycerides, total Cholesterol, High Density Lipoprotein, Free Fatty Acids] during the perioperative period in obese patients undergoing laparoscopic cholecystectomy. Twenty obese patients were included and divided in two groups. In group A (n=10) patients were anaesthetized with propofol and group B (n=10) with etomidate. Blood samples were collected before induction in anaesthesia, just after the end of the operation and at one, two and three hours postoperatively. According to our results, in both groups serum LPL activity showed a significant decrease whereas serum Free Fatty Acids a potent increase over time. Likewise, both groups did not demonstrate significant changes over time in choleseryl-ester transfer protein activity, total cholesterol, triglycerides, High Density Lipoprotein or insulin concentrations in serum. Furthermore, cortisol release was significantly inhibited in the etomidate group while substantially enhanced in propofol group. Additionally, apart of triglycerides, no difference was found between the two groups in all the lipid parameters and insulin concentrations. In conclusion, serum Free Fatty Acids levels and Lipoprotein Lipase activity demonstrated significant alterations in obese patients underwent laparoscopic cholecystectomy and this result did not seem to be related with the anaesthetic agent used for induction in anaesthesia.

Stress-induced lidocaine modification in serum and tissues

The aim of this study is to examine the influence of acute (trauma) and chronic (cold swimming and adjuvant rheumatoid arthritis) stress on lidocaine concentrations in plasma. Forty male Wistar rats were used. The animals were divided into four groups. Group A served as control. Group B underwent mandible osteotomy. Group C was submitted to swimming stress in cold water 4 degrees C for ten minutes daily for 15 minutes, while group D underwent experimental arthritis with Freud's adjuvant. All groups received lidocaine i.m (2.5 mg/kg). Blood samples were collected and FFA (free fatty acid), unbound-lidocaine, albumin and a1-acid glycoprotein concentrations were estimated. Furthermore, the adrenals, heart and liver were isolated. The adrenals' relative weight (adrenal weight/body weight) was assessed, while lidocaine concentrations in the heart and the liver incubation medium were measured by intertechnic a-counter. Lidocaine and FFA levels in serum as well as the adrenal weights demonstrated a significant elevation in stress-groups as compared to the control group. Furthermore, in the stress-groups, lidocaine concentrations in heart tissue were significantly increased, whereas in the liver they were significantly reduced as compared to the control group. Our results indicate that stress can alter lidocaine levels in plasma and tissues, suggesting that stress should be considered an important factor when determining the dosage of lidocaine in clinical application.