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Biomedical subjects

G Arslan

Publications and source records attributed to G Arslan.

At least 55 records · Page 3Linked to original sources
PubMed2001

Successful heterotopic segmental liver transplantation from a live donor to a patient with Alagille syndrome.

Alagille syndrome is characterized by a paucity of bile ducts in the liver. The syndrome is associated with some or all the features of chronic cholestasis, cardiac disease, skeletal abnormalities, ocular defects and a distinctive facial appearance. The most common finding is chronic cholestasis, which causes intractable pruritus, xanthoma, deficiency of certain metabolic nutrients and growth retardation. Cardiac abnormalities are the most common cause of death in these patients. It is unusual to see the clinical picture of hepatic failure resulting in cirrhosis and requiring transplantation, but liver transplantation is indicated in Alagille syndrome patients who have chronic cholestasis. If the disease is diagnosed in childhood, transplantation can improve significantly the patient's prognosis and the quality of life. In recent years, auxiliary liver transplantation has gained popularity for treating both acute and chronic liver disease. Heterotopic segmental liver transplantation is an alternative treatment modality for patients who do not require native liver removal. Individuals with Alagille syndrome are good candidates for this type of treatment. J Pediatr Surg 36:667-671.

Adolescent↗
PubMed2001

Vertebral pneumatocysts.

OBJECTIVE: To review the prevalence and location of vertebral pneumatocysts and evaluate the CT findings of these benign lesions. MATERIAL AND METHODS: Retrospectively we reviewed CT images of 89 patients with suspected disc disease during a 6-month period. RESULTS: Distinctive CT pattern of intraosseous pneumatocysts involving the cervical, thoracic and lumbar spine was found. In 8 patients (9%), 10 vertebral pneumatocysts were detected. Five were located in the vertebral body and 4 of these were associated with vacuum phenomenon in adjacent intervertebral discs. Five were located near the facet joint and all were associated with vacuum phenomenon in adjacent facet joint. CONCLUSION: Intraosseous pneumatocyst is a benign lesion, therefore biopsy and follow-up are unnecessary. Although vertebral pneumatocysts seem to be uncommon with a few reported cases, this study shows them to be more frequent than previously thought.

Adult↗
PubMed2001

(51)CrEDTA colonic permeability and therapy response in patients with ulcerative colitis.

Orally administered (51)Cr-labelled ethylenediaminetetraacetic acid ((51)CrEDTA) has been used to evaluate intestinal permeability in inflammatory bowel disease, especially Crohn's disease. However, information about colonic permeability in ulcerative colitis (UC) is relatively scarce. The aim of this study was to investigate the urinary excretion of orally administered (51)CrEDTA, its relation to disease activity and its response to medical therapy in patients with UC. Forty-three patients with UC and 19 controls were examined. Disease activity was evaluated by endoscopy. In 19 patients with active UC, the (51)CrEDTA permeability test was repeated after medical therapy. (51)CrEDTA (95 microCi; 26 MBq) was given orally after an overnight fast and urine was collected over a 24 h period. The first urine samples were taken 5 h and the second 24 h after the oral administration of (51)CrEDTA. Urine samples were counted in a gamma counter. In controls, the median 5 h and 24 h excretions were 0.10% and 0.93%, respectively. Patients with UC showed significantly increased urine (51)CrEDTA excretion at both time intervals (5 h: 2.41%, P<0.0002; 24 h: 6.72%, P<0.0001). There was also a significant correlation between intestinal permeability and disease activity (5 h: r=0.45, P=0.0025; 24 h: r=0.51 P=0.0006). After medical therapy, (51)CrEDTA urinary excretion was significantly decreased (pre-treatment UC: 7.87%; post-treatment UC: 2.50%; P<0.0002). Briefly, the (51)CrEDTA test reflected colonic permeability in UC and might be useful as an indicator of disease severity. Moreover, this study suggested that, in patients with UC, medical therapy not only leads to the recovery of acute inflammation but also restores mucosal barrier integrity and function.

Adult↗
PubMed2000

Stimulatory and inhibitory effects of adenosine A(2A) receptors on nerve growth factor-induced phosphorylation of extracellular regulated kinases 1/2 in PC12 cells.

Effects of nerve growth factor (NGF), adenosine and an adenosine A(2A) receptor agonist (CGS 21680) on the phosphorylation of extracellular-regulated kinases 1/2 (ERK1/2) were examined in PC12 cells. Adenosine and CGS 21680stimulated ERK1/2, but inhibited the phosphorylation of ERK1/2 induced by a 10 min incubation with NGF. Longer treatment with CGS 21680 and NGF (1-2h) resulted in an additive effect on the activation of ERK1/2. Forskolin exerted the same effects, suggesting that they are mediated by cyclic AMP. These results indicate that adenosine A(2A) receptor induced increases in cyclic AMP can stimulate ERK1/2 phosphorylation per se, inhibit the initial and enhance the late NGF-induced activation of ERK1/2. These results may be explained by the fact that NGF action is mediated via different pathways at early and late time points.

Adenosine↗
PubMed2000

P2Y receptors contribute to ATP-induced increases in intracellular calcium in differentiated but not undifferentiated PC12 cells.

ATP-induced Ca2+ transients were examined in individual PC12 cells of a well defined clone, before and after treatment with nerve growth factor (NGF) to induce a neurone-like phenotype. Using reverse transcriptase PCR these cells were found to express mRNA for several P2 receptors. In undifferentiated cells the ATP-induced Ca2+ response was entirely dependent on Ca2+ influx, could not be mimicked by UTP, alpha,beta-methylene ATP or dibenzoyl ATP or be blocked by pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS). ATP had no significant effect on levels of cyclic AMP or inositol 1,4,5-trisphosphate (InsP3). These results suggest that in undifferentiated PC12 cells ATP mainly acts on a P2X receptor, possibly the P2X4 subtype. After treatment with NGF for 7 days the ATP response was increased and partially sensitive to PPADS. A component of the ATP-induced Ca2+ increase was due to mobilisation of intracellular Ca2+ stores and another to capacitative Ca2+ entry. UTP caused an increase in intracellular Ca2+, and InsP3 formation could be stimulated by ATP and UTP. ATP also caused a small increase in cyclic AMP, but this was abolished in the presence of indomethacin. Thus, after NGF treatment ATP acts partially via a P2Y receptor, possibly the P2Y2 subtype.

Adenosine Triphosphate↗
PubMed2000

Structure and function of adenosine receptors and their genes.

Four adenosine receptors have been cloned from many mammalian and some non-mammalian species. In each case the translated part of the receptor is encoded by two separate exons. Two separate promoters regulate the A1 receptor expression, and a similar situation may pertain also for the other receptors. The receptors are expressed in a cell and tissue specific manner, even though A1 and A2B receptors are found in many different cell types. Emerging data indicate that the receptor protein is targeted to specific parts of the cell. A1 and A3 receptors activate the Gi family of G proteins, whereas A2A and A2B receptors activate the Gs family. However, other G proteins can also be activated even though the physiological significance of this is unknown. Following the activation of G proteins several cellular effector pathways can be affected. Signaling via adenosine receptors is also known to interact in functionally important ways with signaling initiated via other receptors.

Amino Acid Sequence↗
PubMed2000

Pediatric renal transplantation in Turkey: a review of 56 cases from a single center.

In order to assess certain aspects of pediatric kidney transplantation (Tx) in Turkey, we retrospectively analyzed the results of 56 of these pediatric procedures performed at our center. From January 1986 to January 1998, 56 pediatric renal Tx (29 males, 27 females; 0-17 yr of age) were carried out at Başkent University Hospital. All were first-time Tx. Fifty-one (91%) patients were on hemodialysis and four (7.3%) were on peritoneal dialysis prior to Tx. Pre-emptive Tx was performed for only one patient. Living-related donors (LRD) provided 47 (84%) of the transplanted organs and cadaver sources were utilized for nine (16%) patients. The mean cold ischemia time (CIT) for cadaveric donors (CD) was 38.6 h (range 23-56 h). Among living-related graft (LRG) recipients, the average waiting time for Tx was 4 months for Tx performed after 1990 and 8 months for those prior to 1990 (p < 0.05). Median length of hospital stay for Tx was 17 +/- 1.1 and 18 +/- 1.4 days for LRG and cadaveric graft (CG) recipients, respectively. Fifteen of 47 (33%) LRG recipients and six of nine (67%) CG recipients received anti-rejection treatment within 30 days following the Tx surgery. Graft failure developed in 16 (12 LRG, four CG) recipients. Two patients developed Kaposi's sarcoma, 17 and 3 months after Tx. There were total of six deaths (four with functioning grafts). The 1-, 3-, and 5-yr graft survival rates were 93%, 75%, and 63%, respectively, and corresponding patient survival rates were 96%, 92%, and 77%. The social and educational status of 27 patients with functioning grafts were also evaluated. Our results showed that 56% of patients ended their education before high school and only three patients have been married. The high rate of school drop-out and unemployment among pediatric renal transplant recipients in our population underline the need for a more intensive rehabilitation program.

Adolescent↗
PubMed2000

Schwachman-Diamond syndrome. A case report.

Schwachman-Diamond syndrome is an autosomal recessive disorder consisting of exocrine pancreatic insufficiency and neutropenia. The typical pathological finding with this syndrome is fatty infiltration in the pancreas of patients. We report a case of Scwachman-Diamond syndrome examined with abdominal ultrasonography, CT and radiography.

Abdomen↗
PubMed2000

Relationship between intestinal permeability and calprotectin concentration in gut lavage fluid.

BACKGROUND: Calprotectin is released from neutrophils and monocytes, and increased calprotectin levels in stool may serve as a marker of intestinal inflammation. Intestinal permeability is increased in inflammatory bowel diseases, especially in Crohn disease. We studied the relationship between intestinal permeability and calprotectin concentration in intestinal lavage fluid in patients with known or suspected inflammatory bowel disease (IBD). METHODS: Thirty-eight patients were examined; 17 had Crohn disease; 3, ulcerative colitis; and 18, irritable bowel syndrome. Intestinal lavage was performed by means of a nasojejunal tube positioned by gastroduodenoscopy. By means of a peristaltic pump 2 l isotonic polyethylene glycol solution (MW, 3350) containing 50 microCi 51Cr-labelled ethylenediaminetetraacetic acid (EDTA) were administered through the tube over a period of 40 min. The first clear fluid passed per rectum was collected and analysed for calprotectin levels with an enzyme-linked immunosorbent assay method. Urine was collected for 5 h and analysed for gamma radioactivity. 51Cr-EDTA excretion in urine was expressed as percentage of dose administered (that is, intestinal permeability). RESULTS: Both intestinal permeability and calprotectin concentration were significantly higher in patients with IBD than in patients with functional conditions. In Crohn disease the values depended on disease activity but not on whether the disease was located in the small or in the large bowel. There was a highly significant correlation between calprotectin concentration in gut lavage fluid and intestinal permeability (r=0.79, P<0.0001). CONCLUSION: The significant correlation between calprotectin concentration in gut lavage fluid and intestinal permeability supports the view that increased intestinal permeability in IBD might, at least in part, be a consequence of increased transepithelial migration of neutrophils.

Adult↗
PubMed2000

Intraosseous lipoma of the frontal bone. A case report.

Intraosseous lipomas are among the most uncommon bone tumors. They arise most often in the appendicular skeleton. There are very few reported cases of intraosseous lipomas within the skull bones. We report a case of intraosseous lipoma of the frontal bone with conventional radiography and CT findings.

Adult↗
PubMed1999

Reciprocal interactions between adenosine A2A and dopamine D2 receptors in Chinese hamster ovary cells co-transfected with the two receptors.

Human adenosine A2A and rat dopamine D2 receptors (A2A and D2 receptors) were co-transfected in Chinese hamster ovary (CHO) cells to study the interactions between two receptors that are co-localized in striatopallidal gamma-aminobutyric acid-(GABA)ergic neurons. Membranes from transfected cells showed a high density of D2 (3.6 pmol per mg protein) and A2A receptors (0.56 pmol per mg protein). The D2 receptors were functional: an agonist, quinpirole, could stimulate GTPgammaS binding and reduce stimulated adenylyl cyclase activity. The A2A receptor agonist 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine (CGS 21680) decreased high-affinity binding of the agonist dopamine at D2 receptors. Activation of adenosine A2A receptors shifted the dose-response curve for quinpirole on adenosine 3',5'-cyclic monophosphate (cAMP) to the right. However, CGS 21680 did not affect dopamine D2 receptor-induced GTPgammaS binding, but did cause a concentration-dependent increase in cAMP accumulation. The maximal cAMP response was decreased by the D2 agonist quinpirole in a concentration-dependent manner, but there was no change in EC50 and no effect in cells transfected only with adenosine A2A receptors. A2A receptor activation also increased phosphorylation of cAMP response element-binding protein and expression of c-fos mRNA. These effects were also strongly counteracted by quinpirole. These results show that the antagonistic actions between adenosine A2A and dopamine D2 receptors noted previously in vivo can also be observed in CHO cells where the two receptors are co-transfected. Thus, no brain cell-specific factors are required for such interactions. Furthermore, the interaction at the second messenger level and beyond may be quantitatively more important than A2A receptor-mediated inhibition of high affinity D2 agonist binding to the receptor.

Adenosine↗