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G Koliakos

Publications and source records attributed to G Koliakos.

At least 19 recordsLinked to original sources
PubMed2006

The effect of insulin-like growth factor I on healing of colonic anastomoses in cortisone-treated rats.

PURPOSE: This study was designed to investigate whether intraperitoneally injected insulin-like growth factor I is able to protect colonic healing from the adverse effects of hydrocortisone therapy. METHODS: Eighty female Wistar rats were randomized into four groups (20 rats each). After resection of a segment of transverse colon, an end-to-end anastomosis was performed. Hydrocortisone (5 mg/kg body weight) was injected intramuscularly in rats of cortisone (Group B) and insulin-like growth factor I + cortisone (Group D) groups once daily for seven days before and after the operation. Insulin-like growth factor I (2 mg/kg body weight) was intraperitoneally injected in rats of the insulin-like growth factor I (Group C) and the insulin-like growth factor I + Cortisone (Group D) groups immediately after operation and on the second, fourth, and sixth postoperative days. Rats were killed on the seventh postoperative day. Anastomoses were graded macroscopically and histologically, and bursting pressures and anastomotic hydroxyproline levels were recorded. Statistical analyses were performed by using Fisher's exact test for the comparison of proportions and ANOVA for the comparison of means among groups with subsequent post-hoc analysis using Bonferroni correction. RESULTS: Leakage rate was significantly higher in the cortisone (Group B) group. Bursting pressures were significantly lower in the cortisone group, whereas they were significantly higher in the insulin-like growth factor I and insulin-like growth factor I + cortisone groups (Group C and D). Histology revealed a significant decrease of inflammatory cell infiltration, neoangiogenesis, and fibroblast activity in the cortisone group compared with the control group, whereas these parameters were significantly higher in the insulin-like growth factor I and insulin-like growth factor I + cortisone groups. Hydroxyproline levels were significantly higher in the insulin-like growth factor I and insulin-like growth factor I + cortisone groups. CONCLUSIONS: Hydrocortisone inhibits the healing of colonic anastomoses. However, insulin-like growth factor I given intraperitoneally mediates the deleterious effects of cortisone and protects colonic healing in rats.

Anastomosis, Surgical↗
PubMed2006

The characteristics and outcome of primary vesicoureteric reflux diagnosed in the first year of life.

A retrospective trial was performed to study presentation, evaluation, management, complications and outcome of 186 infants with vesicoureteral reflux (VUR). Medical records of 103 male and 83 female infants with mean age at entry 5.97 months were reviewed. Diagnosis was established using radiographic voiding cystourethrogram. At diagnosis, a renal ultrasound and dimercaptosuccinic acid renal scintigraphy were performed in all children. The follow-up included blood pressure measurements, serial urine cultures, haematological and biochemical tests, radionuclide cystography, renal ultrasounds and renal scintigraphy. The majority of infants with reflux, 176/186, presented with one or more episodes of urinary tract infections. In 113 children, reflux resolved spontaneously, 27 underwent surgical or endoscopic correction and 46 are being followed-up to date. Spontaneous resolution after prophylaxis was more frequent in boys (p < 0.0001), in children with grade I or II (p < 0.0001) and unilateral reflux at diagnosis (p = 0.0215). No significant difference could be established with respect to the presence of scars (p = 0.1680) and the number of breakthrough urinary tract infections (p = 0.1078). The data of the present study indicate that spontaneous resolution rate is high in infants, and therefore, early antireflux

Female↗
PubMed2004

High glucose concentrations stimulate human monocyte sodium/hydrogen exchanger activity and modulate atherosclerosis-related functions.

In the present study, the effect of high (20 mM) glucose concentrations on human monocyte sodium/hydrogen exchanger (NHE1) activity, scavenger receptor CD36 expression, cell adhesion, and cell migration have been investigated. Incubation with high glucose concentrations caused an increase in NHE1 activity, as estimated by internal pH and sodium-uptake measurements. This effect was specific for glucose, since it was not observed when monocytes were incubated in the presence of 20 mM of galactose, fructose, or mannitol. In addition, the activation of sodium uptake was inhibited by ethylisopropyl amiloride (EIPA), phloretine and cytochalasine B, and calphostin C. High glucose concentrations also increased the expression of CD36 receptors on the surface of monocytes and positively influenced monocyte migration and adhesion to laminin. EIPA added together with glucose counteracted these effects. The data of the present study suggest that a high glucose concentration can influence atherosclerosis-related monocyte functions via NHE1 activation.

Arteriosclerosis↗
PubMed2003

Urine biochemical markers of early renal dysfunction are associated with iron overload in beta-thalassaemia.

Renal dysfunction in thalassemia patients can be attributed to chronic anemia, and iron overload as well as to desferioxamine (DFO) toxicity. We analyzed the urine of 91 well-maintained homozygous beta-thalassemia patients, with no evidence of renal disease, for early evidence of kidney dysfunction by means of electrophoresis and quantitative biochemical tests. Measurement of liver magnetic resonance imaging (MRI) T2 values and serum ferritin concentration was used to estimate iron overload. In 55 of the 91 patients, urine analysis indicated signs of tubular dysfunction. The urine concentration of albumin and beta 2-microglobulin, as well as the activity of N-acetyl-beta-D-glucosaminidase (NAG), correlated positively with serum ferritin concentration and liver iron deposition, as detected by MRI T2 values. This suggested that the cause of renal dysfunction in homozygous beta-thalassemia is iron overload. On the other hand, the same urine markers did not correlate with age, indicating that chronic anemia or desferrioxamine (DFO) treatment are not related to renal dysfunction in thalassemia.

Acetylglucosaminidase↗
PubMed2002

Short-term human chorionic gonadotropin-induced testosterone rise does not modify leptin levels in eugonadal men.

The aim of this study was to monitor serum leptin concentrations after altering the levels of testosterone, by intramuscular administration of human chorionic gonadotropin (hCG), in eugonadal men. A 7-day monitoring of hCG, testosterone and leptin levels was performed after intramuscular administration of a dose of 5000 IU hCG in these men. Thirty fertile men aged 23-38 years were studied. In addition, 30 women aged 18-34 years with normal ovulatory cycles were studied, to verify reports of sexual dimorphism in serum leptin levels. These 60 individuals were divided into four groups, according to their sex and body mass index (BMI) values. In men, blood samples were collected at 09.00, after an overnight fast, for the determination of hCG, testosterone and leptin levels, and, immediately thereafter, a dose of 5000 IU hCG was administered intramuscularly. Further blood samples were collected at 24-h intervals for a period of 7 days for determination of the same hormones. In women, blood samples were collected only once, at 09.00, after an overnight fast between the 3rd and the 6th day of the menstrual cycle, for determination of serum estradiol and leptin levels. Our results showed that the mean value of leptin in thin men and women was significantly lower than that in obese men and women, respectively. The mean value of leptin in thin women was significantly higher than that in obese men. Serum leptin concentrations decreased significantly, 168 h after short-term hCG administration. There was a significant positive correlation between BMI values and serum leptin concentrations, in both men and women. Our results support the view that hCG administration in eugonadal men does not influence serum leptin levels. Moreover, a short-term increase of serum testosterone levels, after one dose of hCG, is not sufficient to affect and modify leptin secretion mechanisms in vivo.

Adolescent↗
PubMed2001

The effect of leptin on Na(+)-H(+) antiport (NHE 1) activity of obese and normal subjects erythrocytes.

Obesity is currently considered as a chronic metabolic disease, associated with a high risk of cardiovascular complications. Leptin, an adipocyte-derived hormone has a variety target cells influencing a wide range of processes. Possible counteractions of hyperleptinaemia are currently investigated. The Na(+)-H(+) exchanger (NHE 1) is involved in multiple cellular functions and its activation has been related to hypertension and obesity. NHE 1 is present on erythrocytes and can be stimulated by various hormones. Erythrocytes have on their surface a variety of receptors with mostly unknown function. In the present paper, the effect of leptin on erythrocytes NHE 1 activity has been investigated. For this reason, the intracellular pH and sodium influxes were measured before and after addition of leptin in erythrocyte suspensions from normal and obese individuals. Amiloride, a specific NHE 1 inhibitor, and staurosporine a protein kinase C inhibitor were used to inhibit erythrocyte NHE 1. For the binding study leptin was labeled with fluorescein isothiocyanate (FITC) and the binding on erythrocytes was estimated by Scatchard analysis. NHE 1 activity increased in the presence of leptin but significantly less in the obese than in the control group. Furthermore the concentrations of leptin binding sites on the surface of erythrocytes were lower in erythrocytes drawn from obese individuals than in erythrocytes drawn from normal subjects. Since NHE 1 activity has been associated with insulin resistance and hypertension, the activation of this antiport by leptin may represent a link between adipose tissue hypertrophy and cardiovascular complications of obesity.

Adult↗
PubMed2001

Phosphorylation of laminin-1 by protein kinase C.

Several extracellular proteins have been reported to be phosphorylated. Previous studies of our laboratory indicated that laminin-1 can be phosphorylated by protein kinase A (PKA). Moreover, it has been reported that protein kinase C (PKC), although known to be intracellular, can phosphorylate extracellular proteins in the case of cellular damage and/or platelet activation. In the present study we examined the possibility of laminin-1 serving as a substrate of PKC. Amino acid analysis revealed that laminin-1 is phosphorylated by this enzyme on serine residues. Self assembly, heparin binding, and cell attachment on the phosphorylated molecule were then studied. Phosphorylated laminin-1 showed an increased and more rapid self assembly than the non-phosphorylated molecule. Heparin binding and cell attachment experiments indicated enhanced heparin and cell binding capacity of the phosphorylated molecule in comparison to the non- phosphorylated control. These results indicate that laminin-1 can be phosphorylated by protein kinase C. Furthermore, phosphorylation by protein kinase C seems to alter several properties of the molecule, though, the in vivo significance of this phenomenon remains to be studied.

Animals↗
PubMed2001

Electrophoretic analysis of urinary proteins in diabetic adolescents.

Pathological changes in the urine sodium dodecyl sulphate gel electrophoresis (SDS PAGE) patterns often precede the occurrence of any sign of renal involvement in diabetes. However, data concerning the most frequent SDS PAGE pattern of the urine in early stages of type I diabetes mellitus are controversial. In the present study an SDS PAGE technique has been used that provides an adequate sensitivity for the detection of the abnormal pattern. Urinary proteins have been analyzed by SDS PAGE in twenty two diabetic adolescents and twenty four age matched controls. Albumin concentration, and N acetyl-beta-D-glucosaminidase (NAG) activity were also measured in the same samples. There was no significant difference in urine albumin concentration and NAG activity between diabetic children and controls. However twelve patients showed an electrophoretic pattern characteristic for glomerulopathy, two had a pattern indicating tubular dysfunction and another two patients had a mixed pattern. Among the twenty four controls only three showed abnormal electrophoretic patterns. The results support the view that early stages of diabetic nephropathy may involve both glomerular and tubular dysfunction. However the exact clinical and prognostic significance of the information provided by SDS PAGE analysis remains to be elucidated.

Acetylglucosamine↗
PubMed2001

The clinical significance of reverse redistribution in Tl201 cardiac SPET.

UNLABELLED: In an attempt to evaluate the clinical significance of reverse redistribution in Tl201 cardiac SPET, Tl201 SPET examinations included in the data base of our department have been retrospectively reviewed. PATIENTS: Six hundred ninety eight patients demonstrated the pattern of reverse redistribution. For 237 of these patients' cardiac catheterization data were also available. One hundred and six patients of these had a history of myocardial infarction while the rest of them were referred for angina symptoms. RESULTS: Catheterization showed that the infarction area was perfused by a stenosed but patent vessel in 79 of the 106 patients with a history of myocardial infarction (74.5%). Collateral circulation was evident in 21 of these 106 patients (19.8%). Only six patients (5.6%) showed a totally occluded vessel with no obvious evidence of collateral circulation. Of the 131 patients, with no myocardial infarction history, 14 (10.7%) had normal coronary vessels. The rest of the patients (89.3%) demonstrated stenotic vessels perfusing the same area where reverse redistribution was observed. Sixty-three of these patients have been reexamined after 9-36 months. On 15 of these patients (23.8%) the second scintigram showed ischemia in the same segments where reverse redistribution was initially detected. Another 17 of the above patients had a former scintigraphic examination that showed ischemia on the segments that currently demonstrated reverse redistribution. CONCLUSION: The results of the present retrospective study indicate that, in patients with known coronary disease, the pattern of reverse redistribution frequently indicates the ischemic area.

Adult↗
PubMed2001

The effect of insulin on Na+-H+ antiport activity of obese and normal subjects erythrocytes.

BACKGROUND/AIMS: The exact mechanism that links insulin resistance and vascular disease remains unknown. A significantly increased Na+-H+ exchanger (NHE 1) activity and a different effect of insulin on obese individuals erythrocyte NHE 1 has been suggested. These observations may provide a link between obesity, hyperinsulinemia and vascular disease. METHODS: The intracellular pH and sodium influx were measured before and after addition of insulin in erythrocyte suspensions from normal and obese individuals. Amiloride, a specific NHE 1 inhibitor, and staurosporine a protein kinase C inhibitor were used to inhibit erythrocyte NHE RESULTS: Erythrocytes from normal individuals showed increased pH and increased sodium influx after insulin stimulation. This effect of insulin was inhibited by amiloride and by staurosporine as well. In contrast insulin had no effect on NHE 1 activity of erythrocytes from obese individuals. CONCLUSION: These ex vivo data indicate that erythrocyte NHE 1 activity in obese individuals is "insulin resistant". Erythrocytes may provide a simple system for the study of insulin resistance pathways in obesity.

Adult↗
PubMed2000

The significance of PSA/IGF-1 ratio in differentiating benign prostate hyperplasia from prostate cancer.

The importance of insulin-like growth factor 1 (IGF-1) in human serum for the early diagnosis of prostate cancer is controversial. The IGF-1/PSA ratio may improve the performance of prostate specific antigen (PSA) as a prostate cancer marker. IGF-1, along with PSA and free PSA concentration, was measured in the serum of 34 patients with prostate cancer and in 131 patients with benign prostatic hyperplasia (BPH). Although IGF-1 concentration did not significantly differ between the groups, PSA/IGF-1 ratio could clearly distinguish the two groups. In patients with cancer but not in patients with BPH, IGF-1 concentration correlated with PSA and free PSA. The values of PSA and free PSA correlated with each other for both groups. Receivers Operating Curve (ROC) analysis indicated a better sensitivity to specificity ratio for PSA/IGF-1 than for PSA or Free/Total (F/T) PSA.

Adenocarcinoma↗
PubMed1999

Leptin concentrations during oral glucose tolerance test (OGTT) in obese and normal weight women.

OBJECTIVE: To examine possible changes of leptin concentrations after the acute administration of glucose orally (OGTT). DESIGN: Seventy-five grams of glucose were administered per os in one group of obese and normal weight individuals and concentrations of glucose, insulin and leptin were measured at 0, 30, 60, 90 and 120 min. In an age matched control group of individuals with similar BMI water was given and leptin concentrations were measured before and after 30, 60, 90 and 120 min. SUBJECTS: Twenty-seven obese women aged 34+/-1.57 y with BMI 37.1+/-0.8 kg/m2 and 16 normal weight women, aged 32+/-1.13 y with BMI 23.6+/-0.3 kg/m2 formed the experimental group, while 10 obese and 10 normal weight females with similar age and BMI were used as controls. MEASUREMENTS: Weight, height, BMI, body fat, glucose, insulin and leptin at baseline and during OGTT. Variations of the above parameters were calculated from the area under the curve (AUC). RESULTS: Fasting leptin concentrations and AUC were higher in obese than in normal weight women. In obese women, leptin increased significantly in comparison to its basal concentrations 30 and 60 min after the glucose loading. Insulin was also increased, as expected. No correlation was found between insulin and leptin concentrations after glucose loading. Basal concentrations of leptin did not correlate with those of glucose and insulin. No changes in leptin concentrations were found in normal weight women after OGTT. However, a significant positive correlation was found between insulin and basal leptin. Finally, leptin concentrations did not change in obese and normal weight controls after water administration. CONCLUSION: A significant increase in leptin concentrations was found 30 and 60 min after glucose loading in obese individuals. No such increase was found in normal-weight women.

Adult↗
PubMed1999

Stability of serum TSH concentration after non refrigerated storage.

BACKGROUND: The ignorance of how sensitive serum samples for defined assays may be, can lead to overprotecting measures. This attitude not only increases cost and labor in everyday routine but may be responsible for not evaluating series of measurements if performed in serum samples not well stored. METHODS: Thyrotropin (TSH) concentration in serum was tested in three pooled samples drawn from various patients, before and after four days storage at freezing (-15 degrees C), low (4 degrees C), and room temperature (18-22 degrees C). TSH concentration was measured in each part, in 22 replicates using a commercial assay. RESULTS: The variation of the measured values due to the storage conditions was less than 10%, not exceeding the accepted between assay variation. CONCLUSIONS: For the estimation of TSH concentration, patient serum samples may be stored up to four days at 4 degrees C or even at room temperature without significant loss of measurement accuracy.

Cold Temperature↗
PubMed1997

Lung carcinoma imaging using a synthetic laminin derivative radioiodinated peptide YIGSR.

UNLABELLED: The synthetic laminin pentapeptide tyrosyl-isoleucyl-glycyl-seryl-arginine (YIGSR) binds to a metastasis associated high-affinity laminin receptor. The aim of this study was to investigate if the radiolabeled peptide can be considered as a basis for a potential tumor-imaging radiopharmaceutical. METHODS: Iodine-131-labeled YIGSR was injected in mice inoculated with Lewis Lung carcinoma, as well as in normal controls. The experimental animals were imaged on a gamma camera 10 hr after peptide administration. The same peptide was also labeled with 125I and administered to tumor-bearing and normal mice. At various time-points after peptide administration, the experimental animals were killed, and the radioactivity in the tumor, lung, liver and spleen was measured. Microscopic autoradiography was performed in histological sections of the same tissues. RESULTS: The tumor and the spleen of tumor-bearing animals were imaged on a gamma camera. No significant blood-pool background was detected. No other organ except urinary bladder and thyroid was imaged in normal animals. The peptide was retained on tumor and spleen of tumor-bearing animals. Twenty-four hours after peptide administration, the tumor, lung, liver and spleen of animals with tumors contained significantly more radioactivity than the same tissues of equally treated normal controls. The radiolabeled peptide YIGSR was detected by microscopic autoradiography on the surface of certain tumor cells, but not on the surface of any normal cell. CONCLUSION: Although extensive research is still required, the peptide YIGSR can be considered as a basis for the development of a receptor specific radiopharmaceutical useful for the in vivo estimation of the metastatic potential of tumors. This radiopharmaceutical may be helpful in staging and prognostic-related decisions on cancer treatment.

Animals↗
PubMed1996

Haemoglobin O Arab in the Pomak population of Thrace.

A 21 year old woman from Thrace with clinical and laboratory findings of mild hemolysis, was found to be homozygous for haemoglobin O Arab. Blood samples from 15 members of her family and from 42 inhabitants of her village were examined for the presence of Hb O Arab. A high incidence of this variant allele was also detected among the patient's family members as well as in other inhabitants of the village (p = 0.274 +/- 0.049). The possibility that Pomaks, a culturally unique tribe with controversial ethnic origin, may represent one of the original pools for the geographic distribution of the gene in the broader area of the Mediterranean basin is discussed.

Adult↗
PubMed1996

In vivo binding of the radioiodinated peptide YIGSR on B16 melanoma cells.

It has been reported that metastatic melanoma cell lines selectively bind in vitro with the synthetic laminin pentapeptide tyrosyl-isoleucyl-glycyl-seryl-arginine (YIGSR). The aim of this study was to investigate whether the same peptide can bind on melanoma cells in vivo as well. Iodine-125-labeled YIGSR was administered to B16 melanoma-bearing animals. Microscopic autoradiography of tumor and organ sections taken 24 h after peptide administration showed that the peptide did accumulate on the surface of certain tumor cells. The peptide binding cells were frequent in metastatic sites and tumors grown for 24 days and rare in tumors grown for 10 days. A similarly radiolabeled control pentapeptide (peptide DRLKY) did not bind to any tumor cell. It is suggested that the YIGSR binding tumor cells may represent a distinct melanoma cell population with a high metastatic potential.

Animals↗
PubMed1995

Increased lung uptake during myocardial scintigraphy improves the detection and localization of coronary artery disease.

Increased lung uptake during exercise thallium 201 scanning denotes severe ventricular hypofunction. To assess whether there is any relationship between this finding and the stenosis of a single coronary artery, the authors studied 140 patients (age 57.5 +/- 12 years) with both exercise thallium and coronary angiography within three months. A planar view was acquired for two hundred forty seconds immediately postexercise and prior to the single photon emission computed tomography acquisition. Two identical regions of interest outlining the left ventricle and the right lung in the planar view were used for calculation of the lung uptake, expressed as a lung-to-heart counts ratio. The patients were divided into four angiographic groups: (I) lesions at the left anterior descending (LAD), n = 35; (II) stenosis at the circumflex (CRX), n = 35; (III) stenosis at the right coronary artery (RCA), n = 35; and (IV) another group of 35 normal subjects serving as controls. No patient had a previous myocardial infraction (MI) or any cardiac operation. Patients in groups I (0.53 +/- 0.094) and II (0.44 +/- 0.072) had higher lung uptake than those in groups III (0.43 +/- 0.061) or IV (0.42 +/- 0.050). There was no difference between groups III and IV, or II and IV, but the difference between I and IV was of statistical significance (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗