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Biomedical subjects

T Coşkun

Publications and source records attributed to T Coşkun.

At least 37 records · Page 2Linked to original sources

Nutritional assessment of children on haemodialysis: value of IGF-I, TNF-alpha and IL-1beta.

BACKGROUND: Protein-energy malnutrition (PEM) is associated with increased morbidity and mortality in haemodialysis (HD) patients. Insulin-like growth factor I (IGF-I) has proved to be a sensitive marker of malnutrition, while interleukin-1 (IL-1beta) and tumour necrosis factor (TNF) have been found to be raised in catabolic states. METHODS: We have investigated the nutritional status of 17 chronic renal failure (CRF) paediatric patients (8 boys, 9 girls) on maintenance HD. Eight predialysis CRF children (5 boys and 3 girls; mean creatinine 5.1+/-3.2 mg/dl) and 10 healthy children served as control groups. PEM was defined according to anthropometric measurements (triceps skinfold thickness (TST), mid-arm circumference (MAC), and mid-arm muscle circumference (MAMC)). These were correlated with serum IGF-I, IL-1, TNF-alpha, transferrin, and albumin (all sampled before the HD session). RESULTS: In the HD group, TST was reduced in 41.2% of the patients, whereas MAC and MAMC were reduced in 82.4 and 76.5% respectively. TST was depleted in only one of the predialysis CRF children. The degree of reduction in MAC and MAMC were 62.5 and 62.5% respectively. Median serum IGF-I level was decreased in both HD and predialysis CRF patients (205.1 interquartile range (IQR) 194.4 microg/l and 258.8 IQR 155.0 microg/l respectively) compared to the healthy children (418.0 IQR 310.5 microg/l) (P=0.0009 and P=0.01 respectively). Within the HD group, IGF-I levels were lower in patients with malnutrition defined according to TST (145.0 IQR 125.5 microg/l) compared to children with normal TST (301.2 IQR 218.8 microg/l) (P=0.05). IGF-I levels of the HD patients with malnutrition according to TST was also lower than the predialysis CRF patients and healthy children (P=0.04 and P=0.002 respectively). Serum IL-1beta was undetectable in all groups. Median serum TNF-alpha levels were higher in HD and predialysis CRF patients compared to healthy children, albeit statistically insignificant. There was no correlation between TNF-alpha, transferrin or albumin and anthropometric parameters. CONCLUSIONS: Our results support the high prevalence of malnutrition in CRF children, which becomes more pronounced when treatment by HD is initiated. We suggest that determination of IGF-I levels in childhood HD patients in conjunction with anthropometric measurements is useful for identification of malnutrition. We have not been able to demonstrate the catabolic effects of cytokines on this state of protein energy malnutrition.

Adolescent↗

The effect of live measles vaccines on serum vitamin A levels in healthy children.

OBJECTIVE: Serum retinol levels have been shown to be depressed during measles infection. This study aims to demonstrate whether there is any decrease in serum vitamin A level following immunization with live viral vaccine and its relation with vaccine seroconversion in children with measles. Since many children receive measles vaccine alone or in combination with measles-mumps-rubella vaccine, we studied serum vitamin A levels and antibody levels in healthy, well-nourished children before and after immunization with monovalent and combined live attenuated measles vaccine. METHODS: The first group included 21 healthy children between the ages of 9-11 months who received live measles (Schwarz) vaccine. There were also 21 healthy children (range 14-20 months of age) who received measles-mumps-rubella Trimovax (Pasteur Merieux) vaccine. All children were tested for serum vitamin A levels before vaccination, on days 9-14 and 30-42 following both vaccinations. Measles specific antibody levels were also measured on admission and 30-42 days following vaccinations. RESULTS: In both vaccination groups, mean serum vitamin A levels reduced significantly on days 9-14, but increased slightly on days 30-42 in the measles-mumps-rubella vaccinated group (P < 0.05). The baseline and follow-up levels of mean serum vitamin A did not differ between seroconverted and nonseroconverted cases within the measles vaccinated group. CONCLUSION: Serum vitamin A levels are reduced following vaccination with monovalent and combined live attenuated measles vaccines.

Antibodies, Viral↗

Pathways mediating CRF-induced inhibition of gastric emptying in rats.

The corticotrophin-releasing factor (CRF) is shown to be released during stress suggesting that CRF has a physiological role in the mediation of central nervous system (CNS) response to stress, including an inhibitory effect on gastric emptying. In the present study, we have examined the pathways by which intracerebroventricularly (i.c.v.) administered CRF and central CRF activation during stress alter the gastric emptying rate of saline (0.14 M), acid (50 mM), peptone (4.5%) and peptone after preload. The emptying rates of all these test meals were significantly (p < 0.05-0.001) delayed with increasing doses of i.c.v. CRF (0.001, 0.003, 0.01, 0.1, 0.3 and 1 nmol/10 microl), when compared with their i.c.v. saline-treated controls. The 1-nmol dose of CRF inhibited the emptying of acid, peptone and peptone after a preload by 43.8%, 64.1% and 81.1%, respectively. Twenty-minute swim stress delayed gastric emptying rate of saline, acid and peptone solutions significantly (p < 0.001) and the CRF receptor antagonist, alpha-helical CRF (8 nmol/10 microl, i.c.v.), applied before the swim stress, abolished the inhibitory effect of stress on the emptying rate of these solutions. Acute intragastric administration of capsaicin (2 mg/rat) and systemic capsaicin (125 mg kg(-1)) treatment facilitated the gastric emptying rate of acid, peptone and peptone after preload significantly, almost abolishing the inhibitory effect of central CRF (p < 0.001). However, either capsaicin treatment had no effect on stress-induced inhibition of the gastric emptying of none of the solutions, except peptone after a preload. Our findings demonstrate that the gastric inhibitory response induced by swimming as a stress-producing stimulus is mediated by the endogenous release of CRF. They also suggest that CRF exerts its CNS actions on the gastrointestinal tract via vago-vagal, capsaicin-sensitive pathways, probably involving the central cholecystokinin (CCK) mechanisms.

Animals↗

Glucagon-like peptide-1 inhibits gastric emptying via vagal afferent-mediated central mechanisms.

Exogenous administration of glucagon-like peptide-1-(7-36) amide (GLP-1), an insulinotropic hormone, inhibits gastric emptying and acid secretion in humans. The role of GLP-1 as a regulator of gastric function is elusive. In gastric fistula rats, vagal afferent denervation and peripheral administration of the GLP-1 receptor antagonist exendin-(9-39) amide enhanced emptying of a glucose meal, whereas intracerebroventricular exendin was ineffective. The rate of saline emptying was attenuated by peripheral as well as by central administration of GLP-1, and pretreatment with exendin by the respective routes reversed the inhibition by GLP-1. Vagal afferent denervation abolished the central and peripheral action of GLP-1 on gastric emptying. Neither peripheral cholinergic nor adrenergic blockade altered the delay of methyl cellulose meal emptying by intracisternal GLP-1 injection. Acid secretion in conscious pylorus-ligated rats was inhibited by intracisternal GLP-1 administration, whereas systemic GLP-1 was ineffective. These results support the notion that GLP-1 receptors participate in the central and peripheral regulation of gastric function. Furthermore, vagal afferent nerves mediate the inhibitory action of GLP-1 on gastric motor function. GLP-1 may be a candidate brain-gut peptide that acts as a physiological modulator of gastric function.

Animals↗

The effect of nitric oxide synthase blockade and indomethacin on gastric emptying and gastric contractility.

The aim of the present study was to investigate the effect of nitric oxide (NO) synthase inhibition on gastric emptying rate in conscious rats and on gastric muscle contractility. The involvement of NO was also investigated in indometacin-induced (25 mg/kg, s.c.) changes in gastric emptying rate and smooth muscle contractility. L-NAME (NG-nitro-L-arginine methyl ester; 10 mg/kg, i.v.) inhibited the gastric emptying rate compared to controls and this effect was abolished by L-arginine (300 mg/kg, i.v.). Similarly, indometacin treatment led to a significant delay of gastric emptying rate with respect to vehicle-treated rats. Gastric longitudinal and circular muscle strips of L-NAME or indometacin-treated rats showed a reduction in contractile responses to carbachol. The results demonstrate that NO synthase blockade and indometacin treatment delay gastric emptying in conscious rats, concomitant with reduced responsiveness to carbachol, in vitro.

Animals↗

Inhibitory effects of gastrin releasing peptide on gastric emptying in rats.

Gastrin-releasing peptide (GRP) has a wide range of biological actions, including stimulation of the frequency of antral contractions and delaying gastric emptying. The present study was designed to evaluate the role of GRP in the control of gastric emptying of liquid test meals in the rat. The emptying of methyl cellulose given by gavage to fasted rats, or of saline given via the fistula to conscious gastric fistula rats was not influenced by the GRP antagonists, NC-8-89 (Leu13-psi-(CH2NH)-Leu14-bombesin) and 2258U89 ((de-NH2)Phe19, D-Ala24, D-Pro26 psi (CH2NH)Phe27(-GRP (19-27)), at 2 mg/kg, s.c. However, both antagonists (0.02, 0.2 and 2 mg/kg) reversed the inhibitory effect of HCI on gastric emptying in gastric fistula rats (P < 0.05-0.001). When peptone was administered after a preload, but not otherwise, the inhibition of emptying was also partly reversed by both antagonists at all doses used (P < 0.05-0.001). Interestingly, the delay in the emptying of hyperosmolal saline compared to saline, was enhanced at a dose of 0.2 mg/kg of both antagonists (P < 0.05 and P < 0.01). Food intake did not change significantly with the two lower doses of antagonists, but was decreased by the highest dose of NC 8-89. We conclude that GRP specifically inhibits gastric emptying of acid and peptone solutions in the conscious rat.

Animals↗

A case of Pearson syndrome associated with multiple renal cysts.

A 41-day-old infant who had severe metabolic acidosis, anemia, bleeding, hypoglycemia, and proximal tubulopathy was diagnosed with Pearson syndrome. Fibrosis in the liver, severe iron deposition in hepatocytes, and multiple renal cortical cysts were found on postmortem examination. Southern blot analysis of mitochondrial DNA obtained from peripheral blood revealed a heteroplasmic deletion of approximately 3.5 kilobases.

DNA, Mitochondrial↗

The effect of aqueous garlic extract on the levels of arachidonic acid metabolites (leukotriene C4 and prostaglandin E2) in rat forebrain after ischemia-reperfusion injury.

Leukotriene C4 (LTC4) and prostaglandin E2 (PGE2) are known to be highly potent cerebral vasoconstrictors which are formed from arachidonic acid (AA). They enhance vascular permeability, inducing vasogenic edema that may damage the ischemic penumbra after ischemia and reperfusion. The inhibitory effect of aqueous garlic extract (AGE) on AA metabolism in human platelets is known. In this study, following the global ischemic model application to the rats, all underwent 10 min ischemia and were reperfused for different periods. The levels of LTC4 and PGE2 in rat forebrain were then measured. One rat group consisted of 8 rats. In the combined reperfused groups both metabolites increased significantly when compared with the 10 min ischemia alone, no reperfusion group (p < 0.05). In the 8 min reperfused group, PGE2 and LTC4 levels increased significantly at 60 min of reperfusion compared with each corresponding control group (P < 0.005). PGE2 and LTC4 levels were reduced significantly at 60 min of reperfusion compared with the 8 min reperfused group (P < 0.005). AGE (1 ml/kg) reduced both LTC4 and PGE2 levels significantly in the 8 min and 60 min reperfused group (P < 0.001, P < 0.001, P < 0.05, P < 0.01). In conclusion, AGE reduced LTC4 and PGE2 levels at a dosage of 1 ml/kg following 8 and 60 min reperfusion. It may be helpful in reducing AA metabolite levels and preventing injury after ischemic phenomena.

Animals↗

Indicators of nutritional status in Turkish preschool children: results of Turkish Demographic and Health Survey 1993.

The Turkish Demographic and Health Survey (TDHS), conducted in 1993, provided data on the magnitude of malnutrition in a sample of 3152 preschool children from five geographical regions, and on its causal and conditioning factors. Stunting was found to be the dominant form of malnutrition (21 per cent). Altogether 10 per cent of children were underweight and 3 per cent were wasted. There were urban-rural (16 v. 27 per cent, P < 0.001) and regional differences (highest in the East 38 per cent, lowest in the West and North 10 and 14 per cent, respectively; P < 0.001) in the rate of stunting. Among the most important conditioning factors were too early introduction of supplementary foods, mother's educational level, mother's work area, person who takes care of children while mother is at work, birth rank of children, birth spacing, number of children in an individual family, family size, and mother's welfare and hygiene indices. The need for an intersectoral approach for the development of remedial programs to reduce the effect of these factors and for periodic assessment of nutritional status of preschool children is stressed.

Age Distribution↗

Anaesthetic management in maple syrup urine disease.

Two children with maple syrup urine disease undergoing emergency and elective surgery are reported. The administration of ketamine to a 12-month-old boy without neurological problems and propofol infusion to a 5-year-old girl with a history of convulsions, was uneventful. We believe that a full knowledge of the pathophysiology of maple syrup urine disease and potential peri-operative problems associated with the disease are essential, so that patients are not subjected to unnecessary risks.

Anesthesia, General↗

Influence of gallopamil on the gastric effects of stress in conscious rats.

The influence of the calcium-channel blocker gallopamil on cold-restraint stress (CRS)-induced gastric effects was investigated in conscious rats with gastric cannula. CRS, while leading to multiple gastric lesions, reduced gastric acid output and mast cell count, but increased the gastric emptying rate of acid solutions. Intraperitoneally injected gallopamil (1 mg/kg), given 1 h before CRS administration, prevented gastric lesion formation and partially reversed mast cell count and the emptying of acid solutions, but had no further effect on acid output. However, gallopamil in unrestrained rats did not significantly affect acid emptying or mast cell count. Regarding calcium involvement in the pathophysiology of stress-induced gastric lesions, the possible antiulcer actions of gallopamil involved in the prevention of CRS-induced lesion formation may be attributed to its putative stabilizing effect on mast cells and gastric emptying.

Animals↗

Role of neutrophils in indomethacin-induced gastric mucosal lesions in rats.

Nonsteroidal anti-inflammatory drugs (NSAIDs) cause clinically important gastric damage by several mechanisms. In order to evaluate the role of neutrophil infiltration in lesion formation, tissue myeloperoxidase activities were assessed in different gastric layers of the stomach both in rats with normal neutrophil levels and in neutropenic rats. Sprague-Dawley rats were treated either with indomethacin (Indo; 25 mg/kg, s.c.) or the vehicle. A group of rats were made neutropenic by administration of methotrexate (MTX; 2.5 mg/kg i.p.) once a day for 3 days. The stomachs were removed for the determination of lesion index, glutathione, lipid peroxide levels, protein oxidation and tissue myeloperoxidase activities. MTX treatment appeared to reduce neutrophil infiltration significantly while producing insignificant effects on eosinophils and macrophages. Indo administration caused multiple gastric lesions and treatment with MTX significantly reduced lesion index. In rats treated with Indo, neither glutathione nor LP levels showed any significant changes but the protein oxidation was significantly higher than that of other groups. The MPO level of gastric mucosa was increased in Indo-treated rats and reversed by MTX pretreatment. The results of the present study indicate that neutrophil infiltration in the gastric mucosa of rats may be involved in the pathogenesis of NSAID-induced gastric mucosal injury, but no correlation was found between lesion formation and protein oxidation in the gastric mucosa.

Animals↗

Delayed gastric emptying in conscious male rats following chronic estrogen and progesterone treatment.

Several clinical observations and animal experiments have led to speculation concerning the possible effects of pregnancy and pregnancy-associated sex steroids on gastrointestinal function. It was reported that estrogen increases intestinal contractile activity, while progesterone or the combination of estrogen and progesterone decreases it. In order to measure gastric emptying, a methylcellulose test meal was given orally into the stomach of conscious rats. In progesterone-treated rats, at the dose of 0.2 mg/kg, gastric emptying was not significantly different from that of the control, but it was found to be significantly delayed at the dose of 10 mg/kg (P < 0.05). Estrogen treatment at doses of 20 micrograms/kg and 600 micrograms/kg significantly delayed gastric emptying, when compared with controls (P < 0.001). Combined therapy of estrogen and progesterone induced a significant delay in gastric emptying rate compared with the control group (P < 0.001). In the animals with pseudopregnancy treatment (100 micrograms/kg estrogen+ 15 mg/kg progesterone; 7-12 days) the gastric emptying rate was significantly different from that of the control (P < 0.05). We conclude that both estrogen and progesterone exert inhibitory effects on gastric emptying, and this may account for the disturbances in gastrointestinal function that pregnant women frequently experience.

Animals↗

The effect of thermal injury on gastric emptying in rats.

Gastric distension and gastrointestinal discomfort are common complications of burn injuries. This study was designed to examine the effect of thermal injury on the emptying rate of liquids in conscious rats fitted with stainless steel cannulae in the body of the stomach. In rats with partial-thickness burns emptying of the hyperosmolal saline was found to be delayed (P < 0.5) with respect to control only during the chronic phase of injury. However, full-thickness burns delayed hyperosmolal saline emptying in both acute and chronic phases, together with delayed saline emptying in the acute state. Thermal injury did not influence the gastric emptying of peptone and acid solutions, which activate different pathways to delay gastric emptying. Delayed gastric emptying of hyperosmolal solutions may be explained by increased sympathetic and opiatergic nervous activities, resulting in reflex relaxation of gastric smooth muscle.

Analysis of Variance↗

Cardiovascular effects of centrally active cholinomimetics in conscious and anesthetized rats: the role of amygdala.

Central cardiovascular effects of cholinergic agonists depend on the dose, site and mode of administration, species, and to the state of the animal. Intravenous injection of physostigmine and intracerebroventricular injection of carbachol produced pressor and tachycardic responses in urethane-anesthetized rats. Both agents also elicited pressor responses in conscious rats, but bradycardia occurred in the presence of anesthesia. Additionally, pressor responses to physostigmine, but not to carbachol, were significantly exaggerated by urethane anesthesia. These results demonstrate that anesthesia depresses cardiovascular reflexes and the inhibitory control mechanisms on acetylcholine release from the nerve endings involved in cardiovascular regulation. The role of the central nucleus of the amygdala (CNA) was also investigated in this study. The pressor effects of intracerebroventricular injection of carbachol were significantly attenuated by electrolytic ablation of the CNA, but heart rate changes were not altered both in anesthetized and conscious rats. These results indicate that the CNA plays a role in cholinergic control of blood pressure, but not in the regulation of heart rate.

Amygdala↗