The effect of dietary L-arginine intake on the level of antibody titer, the relative organ weight and colon motility in broilers.

This study was carried out to determine the effect of L-arginine (L-Arg) levels in diet at the starter, grower and finisher phases on immune response, organ development, nitric oxide (NO) metabolism and colon motility in broilers. A total of 500 one-day-old Ross-308 broiler chickens of mixed sex were separated into one Arg-deficient group and four experimental groups. Each group was then divided into five subgroups of 20 birds each. Arginine deficient group for all phases was fed a basal diet which contained 10% less L-Arg than optimum Arg requirement recommended by the breeder. Experimental groups were fed a basal diet supplemented with L-Arg which was progressively 10% increased in groups. Thus, the diet contained 90, 100, 110, 120 and 130% of optimum Arg requirement for each phases in groups, respectively. The highest serum infectious bursal disease antibody titer (IBD) was observed in the experimental group which was fed the diet containing 110% L-Arg at grower phase (P < 0.05), whereas Newcastle disease antibody titer did not differ between groups. The relative weight of spleen increased in groups which were fed the diet containing 120 and 130% L-Arg at starter phase as compared to Arg-deficient group (P < 0.05). The group which was fed the diet containing 110% L-Arg showed highest relative weight of bursa Fabricii at grower (P < 0.05) and finisher (P < 0.01) phases. It was observed that serum nitric oxide (NO) concentration decreased in Arg-deficient group (P < 0.05). The amplitude of spontaneous colon contractility did not differ between groups at the end of all three phases. However, the frequency of spontaneous colon contractility in the Arg deficient group was higher at starter (P<0.05), grower (P < 0.01) and finisher (P < 0.05) phases. These results suggest that the supplementation of L-Arg at higher level than optimum Arg requirement in broiler diet has minimal effect on parameters investigated in the study. However, L-Arg-deficiency may negatively affect immune response and the motility of gastrointestinal system due to disruption of NO metabolism at three phases.

Subgross and macroscopic investigation of the coeliac artery in the chinchilla (chinchilla lanigera).

The knowledge of branching and variations of the coeliac artery is clinically important, especially in the surgical operations and non-surgical treatments.Moreover, the chinchillas abdominal region have been used as a model in some surgical experimental researches. In this frame, we have aimed to explain the branching of this artery in the chinchillas detailedly. A total of 10 adult, healthy,male chinchillas (chinchilla lanigera) were used to investigate the origin and the course of the coeliac artery and its branches. Coloured latex was injected into the carotid arteries, following conventional anatomical applications. The results indicated that the coeliac artery was divided into 4 branches such as left gastricartery, hepatic artery, splenic artery and gastrolienal artery. The left gastric artery was a continuity of the coeliac artery and the main vessel of the stomach. The hepatic artery was divided into the left lateral branch, the left medial branch and the right branch. The splenic artery was covered by the pancreas tissue and sent branches to the pancreas. The gastrolienal artery was supplying the fundus of the stomach and the dorsal extremity of the spleen. We believe that the findings will be of help to the researchers interested in the anatomical area, surgeons and experimental researches.

Diagnostics to look beyond the normal appearing brain tissue (NABT)? A neuroimaging study of patients with primary headache and NABT using magnetization transfer imaging and diffusion magnetic resonance.

OBJECTIVE: Novel diagnostics can allow us to "look beyond" normal-appearing brain tissue (NABT) to unravel subtle alterations pertinent to the pathophysiology of primary headache, one of the most common complaints of patients who present to their physician across the medical specialties. Using both magnetization transfer imaging (MTI) and diffusion weighted imaging (DWI), we assessed the putative microstructural changes in patients with primary headache who display the NABT on conventional magnetic resonance imaging (conventional MRI). METHODS: Subjects were 53 consecutive patients with primary headache disorders (40 = migraine with aura; 9 = tension headache; 4 = cluster headache) and 20 sex- and age-matched healthy volunteers. All subjects underwent evaluation with MRI, MTI, and DWI in order to measure the magnetization transfer ratio (MTR) and the apparent diffusion coefficient (ADC), respectively, in eight and six different regions of interest (ROIs). RESULTS: Compared to healthy controls, we found a significant 4.3 % increase in the average ADC value of the occipital white matter in the full sample of patients (p = 0.035) and in patients with migraine (p = 0.046). MTR values did not differ significantly in ROIs between patients and healthy controls (p > 0.05). CONCLUSIONS: The present study lends evidence, for the first time to the best of our knowledge, for a statistically significant microstructural change in the occipital lobes, as measured by ADC, in patients with primary headache who exhibit a NABT on MRI. Importantly, future longitudinal mechanistic clinical studies of primary headache (e.g., vis-à-vis neuroimaging biomarkers) would be well served by characterizing, via DWI, occipital white matter microstructural changes to decipher their broader biological significance.

The ovarian and uterine arteries in the chinchilla (Chinchilla lanigera).

The purpose of this study was to describe arteries supplying the ovaries and uterus in the chinchilla. Five healthy adult female chinchillas were used. In order to reveal the arterial network by dissecting under a stereoscopic microscope, latex coloured with red ink was injected through the common carotid artery. The ovaries of the chinchilla are supplied by the arteriae ovaricae which formed end-to-end anastomoses with the cranial termination of the arteria uterina. Soon after leaving the aorta abdominalis, the arteriae ovaricae extended 2-3 mm caudolaterally, then released 1 branch and extended caudally and bifurcated into 2 further branches. One of these supplied branches to fat tissue. The other branch coursed caudally and anastomosed with the arteria circumflexa ilium profunda and dispersed into fat tissue. The arteria ovarica further subdivided into 2 rami ovaricae. The origins of the uterine arteries were exclusively from the left arteria iliaca externa. The arteria uterina gave a branch to the arteria umbilicalis and consecutive branches which supplied to the ureter, urinary bladder and cranial aspects of the vagina. It also gave rise to 2-3 branches to the cervix and further supplied 10-12 meandering branches to the uterine horns. The arteria uterina gave rise to many tortuous arteries to the uterus and provided 2 further branches to the ovary.

Macroscopic description of the coronary arteries in Swiss albino mice (Mus musculus).

A total of 25 (13 male, 12 female) adult, healthy Swiss albino mice were used to investigate the origin, course and anastomoses of coronary arteries. Coloured latex was injected into the aortic arch to enable these arteries to be clearly discerned. A. coronaria sinistra was larger than A. coronaria dextra. It was divided into a Ramus interventricularis paraconalis and a Ramus circumflexus sinister. However, in 2 specimens, the septal ramus, was observed to stem directly from the left coronary artery, and only 1 ventricular branch arose from the left circumflex. The collateral branches of the paraconal interventricular ramus had a larger diameter and more extensive distribution was observed in these specimens. The A. coronaria dextra was divided into a Ramus septalis and Ramus circumflexus dexter. The Ramus interventricularis subsinuosis was not detected in this study. The ventricular branches of the left coronary artery run intramyocardially whereas the branches of the right coronary artery course subendocardially.

Subgross and macroscopic investigation of blood vessels originating from aortic arch in the chinchilla (Chinchilla lanigera).

A total of 10 adult, healthy, male chinchilla (Chinchilla lanigera) were used to investigate the vessels originating from aortic arch. Coloured latex was injected into the carotid arteries following conventional anatomical applications in all the chinchillas examined. The brachiocephalic trunk and the left subclavian artery arose from the aortic arch at the level of the second intercostal region in the thoracic cavity. The right and left subclavian arteries detached branches at the level of first intercostal region and divided into the following vessels: internal thoracic artery, dorsal scapular artery, vertebral artery, superficial cervical artery and axillar artery. The vessels originating from the aortic arch displayed some significant differences in chinchillas compared to rats, guinea pigs, rabbits, porcupines and other laboratory rodents.

The right coronary artery is absent in the chinchilla (Chinchilla lanigera).

A total of 10 adult, healthy, male chinchillas (Chinchilla lanigera) were used to investigate the origin, course, and termination of the coronary arteries. Coloured latex was injected into the carotid arteries following conventional anatomical applications. In all the chinchillas examined, the left coronary artery was the single coronary artery. The right coronary artery was missing. Additionally, a small vessel originating from the cranial border of the aorta was observed in one chinchilla. The left coronary artery divided into the paraconal, interventricular and left circumflex rami. The left marginis ventricular ramus arose from the paraconal interventricular ramus in eight chinchillas, and from the left circumflex ramus in two. The ventricular and septal branches of the left coronary artery ran subepicardially at the beginning mostly parallel to the muscle fibres, also surrounded by a thin adipose tissue. It was concluded that the only left coroner artery supplied blood to the heart in the chinchilla.

The distribution of the coronary arteries in the Angora rabbit.

The aim of this study was to determine the origin, course, termination and anastomosing of the coronary arteries in Angora rabbits. Eight adult healthy male Angora rabbits were used. Coloured latex was injected into the ascending aorta. A. coronaria sinistra of the Angora rabbit had larger diameter than a. coronaria dextra. It was divided into r. proximalis atrii sinistri, r. interventricularis paraconalis and r. circumflexus sinister in six Angora rabbits as well as r. septi interventricularis in two. R. septi interventricularis that stem directly from a. coronaria sinistra in two animals and from r. interventricularis paraconalis in six was a principal vessel responsible for the septum interventriculare. R. marginis ventricularis sinistri originating from r. circumflexus sinister was the most prominent artery on the auricular surface of the heart. R. interventricularis subsinuosus was not detected in Angora rabbits examined. A. coronaria dextra, crossing the sulcus coronarius immediately after its origin, ran obliquely in direction of the sulcus interventricularis subsinuosus to supply the right portion of the heart. The ventricular and septal branches of a. coronaria sinistra and a. coronaria dextra ran subepicardially at the beginning then intramyocardially and mostly parallel to the muscle fibres as surrounded by a thin adipose tissue. Their atrial branches were seen continuously to run subepicardially.

Gross morphological features of plexus brachialis in the chinchilla (Chinchilla lanigera).

This study documents the detailed features of the morphological structure and the innervation areas of the plexus brachialis in the chinchilla (Chinchilla lanigera). The animals (5 female and 5 male) were euthanased with ketamine hydrocloride and xylazine hydrocloride combination, 60 mg/kg and 6 mg/kg, respectively. Skin, muscles and nerves were dissected under a stereo-microscope. The brachial plexus of the chinchilla is formed by rami ventrales of C5-C8, T1 and T2, and possesses a single truncus. The subscapular nerve is formed by the rami of the spinal nerves originating from C6 (one thin ramus) and C7 (one thick and 2 thin rami). These nerves innervate the subscapular and teres minor muscles. The long thoracic nerve, before joining with the brachial plexus, obtains branches from C6 and C7 in 5 cadavers (3 male, 2 female), from C7 in 4 cadavers (2 male, 2 female) and from C6-C8 in only 1 female cadaver. These nerves disperse in variable combinations to form the extrinsic and intrinstic named, nerves of the thoracic limb. An undefined nerve branch originates from the rami ventrales of C7, C8 and T1 spinal nerves enter the coracobrachial muscle.

5-Hydroxytryptamine-2A receptor gene (HTR 2 A) candidate polymorphism (T 102 C): Role for human platelet function under pharmacological challenge ex vivo.

Although the environmental and life-style factors influencing individual predisposition to acute myocardial infarction (AMI) have been well documented, little is known on the identity of genetic loci that may contribute to risk for AMI. Recently, genetic studies in patients with nonfatal AMI have suggested an association with the T 102 C polymorphism in the serotonin 5-HT(2A) receptor gene (HTR 2 A). Considering the significant role of the 5-HT(2A) receptor in serotonin-induced platelet responses and the contribution of platelet (patho)physiology to thromboembolic events, we postulated that the increased susceptibility to AMI in patients with the T 102 homozygosity may be attributable, in part, to altered serotonin-mediated platelet function. In a group of healthy volunteers recruited from the Eskisehir region in central Turkey (N=37), we investigated the functional consequences of HTR 2 A T 102 C polymorphism in relation to platelet pharmacodynamics ex vivo. The platelet shape change and aggregation response to serotonin were measured with use of the platelet aggregometry and expressed as aggregometer output (mm). Because the circulating catecholamine hormone epinephrine can augment platelet aggregation, pharmacodynamic response (aggregation and its inhibition by 5-HT(2A) receptor antagonist cyproheptadine) was measured in the presence of both serotonin and epinephrine, to mimic the clinical situation in patients. The mean platelet aggregation was higher by 38% in subjects with T 10 2 homozygosity (T/T genotype, N=13) when compared with the carriers of the 102 C-allele (T/C and the C/C genotypic groups, N=24) (39.5 mm+/-12.3 vs. 28.7 mm+/-16.8, respectively) (mean+/-SD) (p<0.05). On the other hand, neither the serotonin-induced platelet shape change nor the cyproheptadine inhibition of platelet aggregation was influenced by the HTR 2 A T 102 C genetic variation (p>0.05). These findings in healthy subjects may provide a mechanistic explanation for the previously reported genetic association between HTR 2 A and AMI. Further genetic association studies of the 5-HT(2A) receptor in patients with AMI in different populations are warranted.

The effect of tilmicosin on cardiac superoxide dismutase and glutathione peroxidase activities.

In this study, the effect of tilmicosin on cardiac superoxide dismutase and glutathione peroxidase activities was investigated. Forty male BALB/c mice were used as material. Ten mice served as a control group, and 30 mice were injected with tilmicosin (25 mg/kg body weight, subcutaneously, with a single injection). After drug administration, they were monitored for 3 days. Tilmicosin caused decreases in cardiac superoxide dismutase and glutathione peroxidase activities.

CYP1A2 activity as measured by a caffeine test predicts clozapine and active metabolite steady-state concentrationin patients with schizophrenia.

Clozapine is an atypical antipsychotic drug and displays efficacy in 30% to 60% of patients with schizophrenia who do not respond to traditional antipsychotics. A clozapine concentration greater than 1,150 nmol/L increases the probability of antipsychotic efficacy. However, plasma clozapine concentration can vary more than 45-fold during long-term treatment. The aim of this study was to assess the contribution of CYP1A2 to variability in steady-state concentration of clozapine and its active metabolite norclozapine. Patients with schizophrenia or schizoaffective disorder were prospectively monitored during clozapine treatment (N = 18). The in vivo CYP1A2 activity was measured using the caffeine metabolic ratio (CMR) in overnight urine. Trough plasma samples were drawn after at least 5 days of treatment with a constant regimen of clozapine. A significant negative association was found between the CMR and the dose-corrected clozapine (r(s) = -0.87,p < 0.01) and norclozapine (r(s) = -0.76,p < 0.01) concentrations. Nonsmokers displayed a higher clozapine (3.2-fold) and norclozapine (2.3-fold) concentration than smokers (p < 0.05). Furthermore, there was marked person-to-person variation in CYP1A2 activity during multiple-dose clozapine treatment (coefficient of variation = 60%). Age, weight, serum creatinine, and grapefruit juice consumption did not significantly contribute to variability in clozapine and norclozapine concentration (p > 0.05). In conclusion, CYP1A2 is one of the important contributors to disposition of clozapine during multiple-dose treatment. Although further in vitro experiments are necessary, the precise metabolic pathways catalyzed by CYP1A2 seem to be subsequent to the formation of norclozapine, hitherto less recognized quantitatively important alternate disposition routes, or both. From a clinical perspective, an environmentally induced or constitutively high CYP1A2 expression can lead to a decrease in steady-state concentration of clozapine as well as its active metabolite norclozapine. Thus, interindividual variability in CYP1A2 activity may potentially explain treatment resistance to clozapine in some patients. CYP1A2 phenotyping with a simple caffeine test may contribute to individualization of clozapine dosage and differentiate between treat ment noncompliance and high CYP1A2 activity.

Lack of association between serotonin-2A receptor gene (HTR2A) polymorphisms and tardive dyskinesia in schizophrenia.

Tardive dyskinesia (TD) is a disabling neurological side effect associated with long-term treatment with typical antipsychotics. Family studies and animal models lend evidence for hereditary predisposition to TD. The newer atypical antipsychotics pose a minimal risk for TD which is in part attributed to their ability to block the serotonin-2A (5-HT(2A)) receptor. 5-HT(2A) receptors were also identified in the basal ganglia; a brain region that plays a critical role in antipsychotic-induced movement disorders. We tested the significance of variation in the 5-HT(2A) receptor gene (HTR2A) in relation to the TD phenotype. Three polymorphisms in HTR2A, one silent (C102T), one that alters the amino acid sequence (his452tyr) and one in the promoter region (A-1437G) were investigated in 136 patients refractory or intolerant to treatment with typical antipsychotics and with a DSM-IIIR diagnosis of schizophrenia. We did not find any significant difference in allele, genotype or haplotype frequencies of polymorphisms in HTR2A among patients with or without TD (P > 0.05). Further analysis using the ANCOVA statistic with a continuous measure of the TD phenotype (Abnormal Involuntary Movement Scale (AIMS) score) found that the AIMS scores were not significantly influenced by HTR2A polymorphisms, despite controlling for potential confounders such as age, gender and ethnicity (P > 0.05). Theoretically, central serotonergic function can be subject to genetic control at various other mechanistic levels including the rate of serotonin synthesis (tryptophane hydroxylase gene), release, reuptake (serotonin transporter gene) and degradation (monoamine oxidase gene). Analyses of these other serotonergic genes are indicated. In summary, polymorphisms in HTR2A do not appear to influence the risk for TD. Further studies evaluating in tandem multiple candidate genes relevant for the serotonergic system are warranted to dissect the genetic basis of the complex TD phenotype.

What will be the role of pharmacogenetics in evaluating drug safety and minimising adverse effects?

In the US, adverse drug reactions (ADRs) rank between the fourth to sixth leading cause of death, ahead of pneumonia and diabetes mellitus. An important reason for the high incidence of serious and fatal ADRs is that the existing drug development paradigms do not generate adequate information on the mechanistic sources of marked variability in pharmacokinetics and pharmacodynamics of new therapeutic candidates, precluding treatments from being tailored for individual patients. Pharmacogenetics is the study of the hereditary basis of person-to-person variations in drug response. The focus of pharmacogenetic investigations has traditionally been unusual and extreme drug responses resulting from a single gene effect. The Human Genome Project and recent advancements in molecular genetics now present an unprecedented opportunity to study all genes in the human genome, including genes for drug metabolism, drug targets and postreceptor second messenger machinery, in relation to variability in drug safety and efficacy. In addition to sequence variations in the genome, high throughput and genome-wide transcript profiling for differentially regulated mRNA species before and during drug treatment will serve as important tools to uncover novel mechanisms of drug action. Pharmacogenetic-guided drug discovery and development represent a departure from the conventional approach which markets drugs for broad patient populations, rather than smaller groups of patients in whom drugs may work more optimally. Pharmacogenetics provides a rational framework to minimise the uncertainty in outcome of drug therapy and clinical trials and thereby should significantly reduce the risk of drug toxicity.

Pharmacogenetic assessment of antipsychotic-induced movement disorders: contribution of the dopamine D3 receptor and cytochrome P450 1A2 genes.

Tardive dyskinesia (TD) is characterized by involuntary movements predominantly in the orofacial region and develops in approximately 20% of patients during long-term treatment with typical antipsychotics. The high prevalence of TD and its disabling and potentially irreversible clinical course is an important shortcoming for treatment with typical antipsychotics. The studies presented in this article evaluate the role of single nucleotide polymorphisms in dopamine D3 receptor (DRD3) and CYP1A2 genes for propensity to develop TD in patients with schizophrenia. In theory, a combined pharmacogenetic analysis of pharmacokinetic and pharmacodynamic targets for antipsychotics should improve our ability to identify subpopulations that differ in drug safety profile. This information may in turn contribute to the design of more efficient clinical trials and thus expedite the development and regulatory approval of newer antipsychotic compounds.

Treatment-resistance to clozapine in association with ultrarapid CYP1A2 activity and the C-->A polymorphism in intron 1 of the CYP1A2 gene: effect of grapefruit juice and low-dose fluvoxamine.

Antipsychotic response to clozapine varies markedly among patients with schizophrenia. The disposition of clozapine is dependent, in part, on the cytochrome P-450 (CYP) 1A2 enzyme in vivo. In theory, a very high CYP1A2 activity may lead to subtherapeutic concentrations and treatment resistance to clozapine. This prospective case study evaluates the clinical significance of ultrarapid CYP1A2 activity and a recently discovered single nucleotide (C --> A) polymorphism in intron 1 of the CYP1A2 gene (CYP1A2*F) for treatment resistance to clozapine. In addition, we describe the effect of grapefruit juice or low-dose fluvoxamine (25-50 mg/d) coadministration on clozapine and active metabolite norclozapine steady-state plasma concentration and antipsychotic response.