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Biomedical subjects

T Coşkun

Publications and source records attributed to T Coşkun.

At least 19 recordsLinked to original sources

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

Alpha-mannosidosis: the first Turkish case.

We describe a 10 month old boy with alpha-mannosidosis who presented with recurrent bronchopneumonia and diarrhea. Facial coarsening, deafness, hepatosplenomegaly, umbilical hernia, pectus carinatum and widespread Mongolian spots were distinguishing features. He also had mild skeletal deformities grouped together as 'dysostosis multiplex', and vacuolated lymphocytes on peripheral blood smear. These findings coupled with an abnormal urinary oligosaccharide pattern led to the suspicion of a lysosomal storage disease in the patient which proved to be alpha-mannosidosis. An exceptionally low level of alpha-mannosidase activity was subsequently found in serum and cultured skin fibroblasts. The patient's brother, who had died at the age of 10 months, had similar features. To the best of our knowledge, this is the first case reported from Turkey.

Humans

Cerebrospinal fluid amino acid levels in newborn infants with intracranial hemorrhage.

Cerebrospinal fluid (CSF) amino acid levels including excitatory amino acids (i.e. glutamate and aspartate) in 25 preterm and 18 full-term newborn infants with no serious disease except intracranial hemorrhage (ICH) were measured. ICH was detected in 13 preterm and six full-term infants on the basis of the clinical, lumbar puncture (LP) and cranial ultrasonography (CraUSG) findings. Twelve preterm and 12 full-term infants who were neurologically healthy comprised the control group. The mean concentration of CSF amino acids did not differ between preterm and full-term infants. The CSF concentrations of taurine, threonine, glycine, alanine, valine, isoleucine, leucine, tyrosine and phenylalanine in preterm infants, and threonine, aspartic acid and alanine in full-term infants were significantly elevated in infants with ICH. These abnormalities, especially in preterm infants, are probably related to cerebral hypoxia in CSF amino acid concentrations in newborn infants with ICH.

Amino Acids

Cyclosporin A reduces the severity of cold-restraint-induced gastric lesions: role of leukocytes.

The objective of this study was to determine the role of cyclosporin A (CsA) on cold-restraint-induced gastric lesions. Animals were subjected to 3 h immobilization at 4 degrees C in plastic restraining devices following a starvation period of 48 h. Gastric samples were obtained for the measurement of myeloperoxidase (MPO) activity, an index of number of peroxidase positive cells and thiobarbituric acid-reactive substances (TBARS; lipid peroxidation). Animals were pretreated with CsA which is a potent immunosuppressant and inhibits ischemia/reperfusion-induced polymorphonuclear leukocyte (PMN) infiltration. Cold-restraint administration significantly elevated the tissue MPO activity and TBARS formation. CsA pretreatment significantly reduced the severity of cold-restraint-induced gastric lesions while attenuating the elevated MPO measurements observed during cold-restraint administration. Animals rendered neutropenic with antineutrophil serum (ANS) exhibited significantly less gastric mucosal injury normally observed after cold-restraint stress. Neither CsA nor ANS treatment effected the elevated TBAR levels, indicating that PMNs are not involved in the lipid peroxidation process observed after cold-restraint stress. In conclusion, the results of this study indicate that CsA is capable of inhibiting cold-restraint-induced gastric mucosal injury and can attenuate the cold-restraint-induced increases in gastric MPO measurements. Our results also indicate that PMNs may be the important mediators of cold-restraint-induced gastric lesions.

Animals

Two missense mutations causing tyrosinemia type 1 with presence and absence of immunoreactive fumarylacetoacetase.

Hereditary tyrosinemia type 1, due to a deficiency of fumarylacetoacetase (FAH), is characterized by progressive liver damage and renal tubular dysfunction and may occur in an acute or a chronic form. An Ala 134 to Asp (GCT to GAT) transition was found in one Turkish and two Norwegian patients with chronic tyrosinemia. SphI digestion of polymerase chain reaction (PCR) amplified genomic DNA identified the mutation and showed that the patients were heterozygous. All these patients had immunoreactive FAH protein in fibroblasts. Another Norwegian patient with chronic disease, without FAH immunoreactive material in fibroblasts, had a Pro 342 to Leu mutation (CCG to CTG). This mutation was identified by MspI digestion of PCR amplified genomic DNA, and the patient was heterozygous. Northern blotting showed FAH mRNA of normal size and amounts in all patients. Site directed mutagenesis and translation in a rabbit reticulocyte lysate demonstrated that both mutations abolished FAH activity.

Amino Acid Metabolism, Inborn Errors

Sodium chloride deficiency in cystic fibrosis patients.

Sodium chloride deficiency (SCD) was observed within the 1st year of life in 12 of 46 cystic fibrosis (CF) patients between July 1989 and September 1992. All patients showed sweating, loss of appetite, fever, vomiting, irritation, dehydration, weakness, and cyanosis during an attack. Mean plasma sodium, potassium and chloride levels were 122.9 (range 106-135), 2.5 (range 1.6-3.5), and 73.3 (range 60-90) mEq/l respectively. Alkalosis and elevated plasma renin activity were detected in all patients. Of the patients, 50% showed microscopic haematuria, and hypercalciuria was detected in two out of four patients. Low urinary sodium and high urinary potassium were observed in the four examined patients. Increased creatinine, BUN and uric acid values returned to normal with treatment. All the patients were treated initially with intravenous fluids and electrolyte solutions. All patients were less than 7 months of age during the first attack, five received only breast milk and the others breast milk with formula milk. Their oral salt supplement was 2-4 mEq/kg per day, which is recommended for CF patients, but could be deficient in excessively sweating infants. The genotype of these patients might be cause of high salt losses. F508 is the most common mutation with the frequency of 38% in our CF patients with SCD, but the frequency of unknown mutations is high (54%).

Alkalosis