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Biomedical subjects

G Can

Publications and source records attributed to G Can.

At least 19 recordsLinked to original sources
PubMed1999

Renal duplex Doppler ultrasonography as a predictor of preclinical diabetic nephropathy in children.

PURPOSE: To perform Doppler US in patients with insulin-dependent diabetes mellitus (IDDM) as a predictive method in diabetic nephropathy (DN). MATERIAL AND METHODS: Twenty-five patients with type I diabetes mellitus underwent renal Doppler US examination. Children were divided into three age groups: group I, 3-7 years; group II, 8-10 years; and group III, 11-18 years. The age-matched control group consisted of 56 healthy children who underwent renal Doppler US only. RESULTS: The mean values of the resistive index (RI) were, respectively, 0.64+/-0.03, 0.59+/-0.04, 0.59+/-0.02 in age groups I, II, and III for healthy children and 0.68+/-0.03, 0.62+/-0.04, 0.59+/-0.04 in age groups I, II, and III of the diabetic patients. There were no significant differences between the diabetic and healthy subjects. The mean RI value was not different in the patients with glomerular hyperfiltration compared to patients with normal filtration rate. Additionally, there were no significant differences between the mean RI value in patients with or without microalbuminuria. CONCLUSION: Renal Doppler US is not useful for prediction or for early diagnosis of DN.

Adolescent↗
PubMed1998

Effect of a somatostatin analogue (SMS 201-995) on tear secretion in rats.

PURPOSE: In this study we investigated the effect of a somatostatin analogue, octreotide, (SMS 201-995) on tear secretion in rats. METHOD: The animals were anaesthetized intraperitoneally (ip) with urethan (1.2 g/kg) The drugs were injected subcutaneously (sc.). Tear samples were collected by folding a 5 mm section of the Schirmer strip over the lower lid margin to absorb tear fluid from the lower conjunctival sac for 5 mm. Forty animals were divided into four groups (n = 10). Group I (control) received 1 ml of saline, group 2 received 100 microg/kg of SMS 201-995, group 3 received 50 microg/kg of acetylcholine (Ach), group 4 received 100 microg/kg of SMS 201-995 and 30 min later 50 microg/kg of Ach. At t = 0 the local anesthetic proparacain HCI was instilled onto the ocular surface to minimize reflex secretion. Baseline secretion was measured before administering the various treatments. RESULTS: While Ach alone significantly increased tear secretion, SMS 201-995 reduced it compared to saline (control) (p<0.0001, p<0.001, respectively). SMS 201-995 combined with Ach decreased tear secretion compared to Ach alone (p<0.03). CONCLUSION: SMS 201-995 significantly inhibits Ach stimulated tear secretion in rats.

Acetylcholine↗
PubMed1998

Inhibition of penile erection in rats by a long-acting somatostatin analogue, octreotide (SMS 201-995).

OBJECTIVE: To assess the effect of a new somatostatin analogue (SMS 201-995, octreotide) on erectile function in rats. MATERIALS AND METHODS: Animals were fasted and anaesthetized intraperitoneally with pentobarbital. A cannula was placed in the trachea and the femoral vein cannulated for intravenous infusion. The hypogastric and pelvic nerve, major pelvic ganglion, and the nerve fibres to the lower genitourinary tract were identified. In 20 animals, these nerves were stimulated unilaterally using bipolar silver-wire electrodes; the stimulation was repeated every 15 min for 1 h. Twenty animals were divided into two equal groups; after measuring penile erection to obtain basal values, the animals received either saline or 50 micrograms SMS 201-995 over 1 h and 30 min later, the stimulation was repeated. RESULTS: After administering SMS 201-995 or saline, the levels of penile erection reduced linearly in both groups, but SMS 201-995 caused a greater decrease than in the control group (P < 0.05) and from baseline (P < 0.01) at all times. CONCLUSION: SMS 201-995 inhibits penile erection in rats and the systems may serve as an in vivo animal model for further investigation.

Animals↗
PubMed1998

Identification and sequencing of a putative variant of proopiomelanocortin in human epidermis and epidermal cells in culture.

Proopiomelanocortin (POMC) is a precursor polypeptide for various bioactive peptides, including adrenocorticotropic hormone, alpha-, beta-, and gamma-melanotropin, beta-endorphin, and beta-lipotropin. Although the classical source of POMC is the pituitary, various studies indicate the expression of POMC in several nonpituitary tissues. In this study, in situ hybridization with anti-sense cRNA riboprobe was used to show expression of POMC mRNA in human epidermis and cultured human epidermal cells (melanocytes and keratinocytes). POMC mRNA was amplified by reverse transcriptase-polymerase chain reaction using anti-sense and sense primers designed from Exons 2 and 3 of POMC gene. A approximately 300 bp product was present in normal human skin, grafted human skin, and cultured normal human melanocytes and keratinocytes. By Southern analysis this product was hybridized specifically to the POMC cDNA. Sequence analysis of the reverse transcriptase polymerase chain reaction product from tissues or cells showed 85% homology to POMC cDNA from human, bovine, pig, and monkey sources. This suggests the existence of a putative isoform or variant of POMC mRNA in human epidermis.

Animals↗
PubMed1997

Epidermal growth factor receptor expression following small bowel resection.

BACKGROUND: Adaptation following massive small bowel resection (SBR) is an important compensatory response. While epidermal growth factor (EGF) has been shown to augment this response, the mechanism and role of EGF and its intestinal receptor (EGF-R) during adaptation are not known. The purpose of this study was to determine the effect of massive SBR and adaptation on intestinal expression of EGF-R. MATERIALS AND METHODS: Male Sprague-Dawley rats underwent either a 75% mid-SBR with primary reanastomosis or sham operation (bowel transection with reanastomosis). Ileal mucosa was harvested from animals of each group at 6 and 12 hr, 1, 3, and 5 days, and 1, 2, and 4 weeks after operation. Expression of EGF-R protein was studied by Western blotting. Expression of EGF-R mRNA was determined by quantitative reverse-transcriptase polymerase chain reactions normalized to beta-actin. RESULTS: When compared with sham, SBR resulted in a modest (32%) increase in the expression of EGF-R mRNA at 1 week (P < 0.003). A twofold greater expression of EGF-R protein corresponded to this time point. While not statistically significant, expression of EGF-R mRNA was slightly greater after SBR at every other time point measured. CONCLUSION: Following massive SBR, expression of both EGF-R mRNA and protein is slightly increased in the ileum with a more pronounced increase in protein. These findings, which have not previously been reported, suggest that changes in EGF-R signaling may not play a major role during the initiation and or progression of intestinal adaptation following massive SBR.

Animals↗
PubMed1997

Coating of silicone-based impression materials in a glow-discharge system by acrylic acid plasma.

OBJECTIVES: The main purpose of this study was to demonstrate an increase in the wettability of silicone-based impression materials after coating them with a hydrophilic film in a glow-discharge system. METHODS: Two vinyl polysiloxane impression materials, Extrude (Kerr) and Accuflex (GC America Inc.) were used. Impression specimens were treated in a glow-discharge reactor at a radio frequency of 13.56 MHz at different discharge powers (5-20 W) and exposure times (5-60 min). Surface analysis of the specimens was done by FTIR. Surface contact angles were obtained by a captive-bubble method. These results were analyzed by ANOVA and Duncan's Multiple Range test (p < 0.05). The total number of voids on the die stone casts was observed microscopically. Linear dimensional accuracy, detail reproducibility, and surface hardness of the die stone casts were also determined. A Student t-test was performed for statistical analysis of these parameters (p > 0.05). RESULTS: FTIR spectra indicated that the number of hydroxyl groups on the surfaces increased (p > 0.05) because of the glow-discharge treatment. Contact angle measurements showed an increase (p < 0.05) in surface hydrophilicity. Total void formation in the stone casts decreased. There were no significant differences in the linear dimensional accuracy, detail reproducibility, and hardness, before and after glow-discharge treatment (p > 0.05). SIGNIFICANCE: It was concluded that the surface wettability of the impression materials may be increased by plasma deposition, and therefore, the formation of voids was reduced in the stone casts.

Acrylates↗
PubMed1996

Leukocyte lipid peroxidation, superoxide dismutase, glutathione peroxidase and serum and leukocyte vitamin C levels of patients with type II diabetes mellitus.

In the present study, leukocyte lipid peroxidation, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and serum and leukocyte vitamin C levels of patients with type II diabetes mellitus and healthy controls were investigated. Patients consisted of 53 cases (23 male, 30 female) aged 35-75 years and controls of 34 subjects (15 male, 19 female) aged 34-66 years. Leukocyte lipid peroxidation of diabetics was significantly increased (P < 0.05) whereas vitamin C level was decreased (P < 0.05) compared to those of controls. There was no significant difference in the other parameters. Also, there was no correlation between the above parameters and HbA1c and glucose levels. Our results show that leukocytes of diabetics are affected by oxidative stress which might be a reason for decreased microbicidal activity.

Adult↗
PubMed1996

Effect of verapamil on portal and splanchnic hemodynamics in patients with advanced posthepatitic cirrhosis using duplex Doppler ultrasound.

PURPOSE: To assess the effect of verapamil (80 mg) oral administration on portal and splanchnic hemodynamics in patients with advanced posthepatitic cirrhosis using duplex Doppler ultrasound (US). METHODS: Fourteen patients with post-hepatitic liver cirrhosis were included in the study. Duplex Doppler sonographic examinations were performed before, and 2-3 h after, 80 mg verapamil oral administration. Portal and splanchnic hemodynamics including vessel diameters (mm), mean flow velocities (cm/s), blood flows (ml/min), Doppler indices such as pulsatility and resistive indices (PI and RI), were investigated before and after verapamil administration. RESULTS: After verapamil administration; diameter of portal vein, splenic vein, and superior mesenteric artery (SMA) showed increase of 8%, 10%, and 7% (P < 0.05 to < 0.001), respectively. Increases of 20%, 38%, and 47% were found in blood flows (P < 0.05 to < 0.0001) with respect to the above vessels. Decreases of 17%, 10%, 11%, and 7% were found in SMA PI, SMA RI, splenic artery (SA) PI, and SA RI, respectively (P < 0.05 to < 0.0001). CONCLUSIONS: Verapamil appears to have splanchnic, portal, splenic, portocollateral and probably intrahepatic vasodilator effects in patients with advanced posthepatitic liver cirrhosis. Verapamil should be further investigated in the treatment of patients with advanced liver cirrhosis with prospective studies measuring portal and wedged hepatic pressure.

Administration, Oral↗
PubMed1996

Intestinal adaptation following massive small bowel resection in the mouse.

BACKGROUND: Transgenic mice represent powerful tools for studying the role of genes and their expression under multiple conditions, and they may provide a unique model for studies of intestinal adaptation after massive small bowel resection (SBR). This study characterized a successful model for SBR and intestinal adaptation in the mouse. STUDY DESIGN: Sham operation (bowel transection with reanastomosis) or SBR was performed on male C57BL/6 mice. A solid or liquid diet, various sizes of monofilament suture for the anastomosis, and resection of 50 or 75 percent of the proximal small intestine were studied. In other studies, intestinal adaptation was characterized as changes in intestinal wet weight, DNA, protein, villus height, crypt depth, and crypt cell proliferation rates at 12 hours, 24 hours, three days, and one, two, and four weeks after 50 percent SBR. RESULTS: Survival was significantly improved with a liquid diet (8 percent compared with 88 percent; p < .001) and modestly improved by using the smallest suture for anastomosis (60 percent for 7-0 compared with 88 percent for 9-0; p = not significant). Mice did not tolerate more than 50 percent SBR (16 percent survival rate for 75 percent SBR compared with 85 percent survival rate for 50 percent SBR; p < .01). Small bowel resection augmented ileal wet weight, DNA and protein content, villus height, crypt depth, and crypt-cell proliferation rates. CONCLUSIONS: Provision of a liquid diet, using a small suture for anastomosis, and resection of no more than 50 percent of the proximal small intestine are important for survival. This model will permit researchers using transgenic mice to better understand critical genes during intestinal adaptation after SBR.

Adaptation, Biological↗
PubMed1996

Relationship between various functional impression techniques and different operators.

The purpose of the present investigation was to determine the relationship between the reproducibility of soft tissue contours by three different functional impression techniques and four dentists for mandibular distal-extension removable partial dentures. The selected functional impression methods were Lejoyeux, Rouot and McLean techniques. A mucostatic impression technique was used for the control group. To compare and measure the degree of tissue displacement, a three-dimensional coordinate measuring system was used. The differences in vertical displacement of soft tissue among the operators were statistically determined for each impression technique used. Lejoyeux technique produced the least variation in tissue displacement followed respectively by McLean, mucostatic and Rouot methods.

Computing Methodologies↗
PubMed1995

Retentive characteristics of different dental magnetic systems.

It is necessary to recognize the retentive capabilities of magnetic systems to assess their clinical performance. This study determined the retentive characteristics of one open-field and two closed-field commercial dental magnetic systems. The effect of speed of separation and the space between the magnet and its keeper on the retention force were evaluated. The magnets and their respective keepers, embedded in acrylic resin blocks, were tested with fast and slow speeds of separation. The maximum retention values of the magnetic systems were tested with slow speed of separation. The fast speed of separation was designed to reflect mandibular movement. Various spaces were developed between the magnets and their respective keepers, and magnetic systems were tested only in slow speed of separation. The fast speed of separation dramatically lowered the retention force of each magnetic system. As the space increased between the magnet and keeper, the retention values diminished rapidly. While closed-field systems demonstrated higher retentive forces than the open-field system, the open-field system was less affected by the various spaces.

Denture Retention↗
PubMed1995

Nephrocalcinosis in newborn.

Nephrocalcinosis is uncommon in childhood, and almost always develops outside the newborn period. Over the last decade, nephrocalcinosis due to multifactorial pathogenesis has increased in very low birthweight infants. In this report a 23 day old full-term baby with nephrocalcinosis secondary to distal renal tubular acidosis is described.

Acidosis, Renal Tubular↗
PubMed1995

Breast milk beta-glucuronidase and prolonged jaundice in the neonate.

Breast milk samples from mothers of breast-fed, healthy, term newborns with unexplained prolonged jaundice were analyzed for beta-glucuronidase activity. Mean enzyme activity was 75.7 +/- 34.5 modified Sigma units/ml in the breast milk samples ingested by the study group of jaundiced babies (n = 25) and 82.2 +/- 40.1 modified Sigma units/ml in the samples ingested by the control group of non-jaundiced babies (n = 20) (p > 0.05). Enzyme activities at 2, 3 and 4 postnatal weeks were 101.0 +/- 39.9, 66.0 +/- 20.7 and 57.0 +/- 22.4 modified Sigma units/ml in the study group and 87.9 +/- 36.1, 58.5 +/- 15.0 and 88.3 +/- 49.1 modified Sigma units/ml in the controls. The differences were not statistically significant (p > 0.05). We conclude that breast milk beta-glucuronidase activity may be a contributory factor, in the presence of other variables, in hyperbilirubinemia but it is neither the main nor the only cause of prolonged jaundice in neonates.

Adult↗
PubMed1995

[Disorders of kidney function in asphyxic newborn infants].

In this study it was aimed to investigate the renal function disturbances at an early stage of term newborn babies with perinatal asphyxia. 18 term newborn babies with the diagnosis of perinatal asphyxia were followed in the first 3 days of their lives, and various laboratory tests were applied to evaluate the renal functions. The results were compared with 10 healthy newborn who were chosen as a control group. The renal functions glomerular filtration rate (GFR) and fractional sodium excretion (FENa) were found significantly impaired up to 60% in the asphyctic babies especially those whose clinical presentation was expected to be severe.

Acute Kidney Injury↗
PubMed1994

Effect of surface treatments of porcelain on the shear bond strength of applied dual-cured cement.

The effect of different surface treatments of porcelain on the shear bond strength of the applied dual-cured cement was examined. Acid etching with hydrofluoric acid, roughening the porcelain surface by means of grinding with a diamond bur, and the use of silane coupling agent alone and with combinations of these surface treatments were used. Silane treatment resulted in a shear bond strength on roughened porcelain surfaces that was statistically significantly greater than all other treatment groups (p < 0.05). However the use of two mechanical bond systems together with a chemical bond did not improve the shear bond strength.

Analysis of Variance↗
PubMed1993

Neonatal suppurative parotitis: a vanishing disease?

A case of neonatal suppurative parotitis due to Klebsiella pneumoniae is described. This is the first case reported in the last 20 years. Infection with unusual microorganisms should be taken into account when planning antibiotic treatment, especially in hospital acquired infections of the salivary glands in the newborn.

Amikacin↗