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Biomedical subjects

O Güven

Publications and source records attributed to O Güven.

At least 19 recordsLinked to original sources
PubMed2005

MIB-1 expression in odontogenic epithelial rests, epithelium of healthy oral mucosa and epithelium of selected odontogenic cysts. An immunohistochemical study.

The aim of this study is to investigate the proliferative potential of rests of odontogenic epithelium found in follicles of unerupted teeth, epithelium of oral mucosa and epithelial linings of various odontogenic cysts. MIB-1 expression was studied in the rests of odontogenic epithelium (n=10), healthy oral mucosa (n=10), odontogenic keratocysts (n=10) and other odontogenic cysts (n=10) using an avidin-biotin peroxidase technique on paraffin sections. The number of positively stained cells was counted on 10 representative areas of epithelium using a x40 objective. The average number of MIB-1 positive cells in each group was calculated. No MIB-1 positive cells were seen in the rests of odontogenic epithelium. The mean numbers of MIB-1 positive cells detected within the epithelium of oral mucosa, and of radicular and dentigerous cysts were similar. The number of MIB-1 positive cells was found to be increased in the presence of marked inflammatory cell infiltration. The highest number of MIB-1 positive cells was seen in the keratocysts. These findings suggest that removal of an unerupted tooth to prevent the possibility of neoplastic transformation of rests of odontogenic epithelium is not a justifiable rationale.

Cell Proliferation↗
PubMed2003

Remodelling in young sheep: a histological study of experimentally produced defects in TMJ.

QUESTIONS UNDER STUDY: In this study, experimentally induced surgical defects of the mandibular condyle were evaluated histologically 3, 6 and 9 months postoperatively to investigate the capacity for remodelling which is one of the most important features of the temporomandibular joint. METHODS: In three healthy sheep standardised surgical defects were produced on each right condylar head. The left temporomandibular joints served as controls. No treatment was performed on the surgical defects and function was not restricted postoperatively. At the end of the experimental period the sheep were sacrificed and a histological evaluation was carried out. RESULTS: Histologically, no disturbance was observed during the healing process in bone and cartilage. Although function was not limited throughout the study, it was observed that the experimental surgical defects had healed completely. CONCLUSIONS: This result points to the condyle's high capacity for repair and remodelling.

Animals↗
PubMed2001

Investigation of active substance release from poly(ethylene oxide) hydrogels.

The uptake and controlled release of model active substances from poly(ethylene oxide), (PEO), hydrogels synthesized by irradiation were investigated. For the characterization of network structure of PEO hydrogels, swelling properties in water and the number average molecular weight between crosslinks were determined. Salicylic acid, phthalic acid and resorcinol were used as model substances for their controlled release from PEO hydrogels. The effects of dose rate, total dose and chemical structure of active substance on the uptake and release have been studied. The active substance uptake capacity of hydrogels was found to be lowest for phthalic acid and highest for resorcinol in the gel system obtained by irradiation both at low and high dose rates. The release was lowest both in rate and in total amounts in hydrogels containing phthalic acid, more in those with salicylic acid and highest in those with resorcinol. The physical and chemical factors affecting the release of model compounds such as the network structure of hydrogels and hydrogen bond formation between the adsorbent and PEO chains were discussed.

Anti-Infective Agents↗
PubMed2001

Effect of left atrial size and function on P-wave dispersion: a study in patients with paroxysmal atrial fibrillation.

BACKGROUND: Paroxysmal atrial fibrillation (PAF), a common arrhythmia, is caused by the fractionated and nonhomogeneous propagation of sinus impulse. HYPOTHESIS: This study was undertaken to examine the effect of left atrial (LA) dimension and function on P-wave dispersion (deltaP) in unselected patients with PAF and health controls. METHOD: In this study, 62 consecutive patients with PAF (32 men, 30 women, mean age 55+/-11 years) and 62 age- and gender-matched healthy controls (33 men, 29 women, mean age 52+/-13 years) were studied to compare the effect of LA size, volume, and function on deltaP (difference between maximum and minimum P-wave duration on 12-lead electrocardiogram). RESULTS: P-wave dispersion in patients with PAF and normal LA diastolic diameter (LAD) was longer than that in controls with normal LA size (53+/-8 vs. 34+/-8 ms, p < 0.001). P-wave dispersion increased in patients with PAF (62+/-12 vs. 53+/-8 ms, p = 0.003) and controls (40+/-7 vs. 34+/-8 ms, p = 0.005) with increased LAD. Presence or absence of PAF did not interact with LAD for their effect on deltaP (2 x 2 analysis of variance test p = 0.20). In the PAF group, deltaP correlated with LAD (r = 0.43, p = 0.002), LA diastolic volume (r = 0.6, p < 0.001), and LA ejection fraction (AEF) (r = - 0.33, p = 0.05). The AEF was preserved when LAD increased in the patients without PAF (0.52+/-0.07 vs. 0.57+/-0.10, p = NS), however was significantly decreased in the PAF group (0.37+/-0.12 vs. 0.49+/-0.10, p = 0.01). On multivariate logistic regression analysis, only deltaP retained significance on development of PAF. CONCLUSION: It was concluded that deltaP increased in patients with PAF and normal LA size. In controls with increased LA size, deltaP increased but did not reach the levels attained in patients with PAF. The AEF was decreased in patients with PAF but was preserved in those without PAF. These findings can be explained by the changes in LA microarchitecture which concurrently decreased atrial myocardial contraction, increased deltaP, and predisposed to PAF.

Adult↗
PubMed2001

Transpedicular decancellation osteotomy in the treatment of peridural fibrosis.

From 1992 to 1997 a series of 12 multiply operated (averaging 2.5 previous operations) patients with recurrent peridural fibrosis and postlaminectomy kyphosis underwent surgery at our clinic. The surgery was designed to restore the physiological lordosis and relax tethered cord and epidural veins by transpedicular decancellation osteotomy at a vertebra other than the vertebra with peridural fibrosis. This paper presents the long-term functional outcome of these 12 patients. Clinical assessments were conducted pre-operatively and at 3-month intervals postoperatively and included X-ray assessment and evaluation of the patients' functional status by Oswestry Disability Index (ODI) and of pain by visual analogue scale (pain VAS). All symptoms and the pain due to peridural fibrosis disappeared in the early postoperative period. Patients had tower disability and pain scores at their early and long-term follow-ups (follow-up period 24-74 months, mean 36.3 months). For patients with failed medical therapy for peridural fibrosis accompanied by lumbar kyphosis or hypolordosis, transpedicular decancellation osteotomy should be the surgical treatment of choice.

Adult↗
PubMed2001

Anterior urethral valve as a cause of end-stage renal disease.

Although posterior urethral valves are predominant as a cause of obstructive uropathy in children, anterior urethral valves may also appear as the underlying etiologic factor in end-stage renal disease that results from obstruction. Two cases are presented of anterior urethral valve patients that were admitted with end-stage renal disease. The first case was successfully treated with diverticulectomy and urethral reconstruction in preparation for renal transplantation. The second case, however, had been on cystostomy drainage for 6 years and also had a contracted bladder. A more extensive lower urinary tract reconstruction was delayed. Children with poor stream and recurrent infections should be evaluated carefully and anterior urethral valve or diverticula should be considered in differential diagnosis of obstructive lesions.

Adolescent↗
PubMed2001

Remodelling following condylar fractures in children.

PURPOSE: In this study, 18 children with 21 subcondylar fractures sustained during their growth period (age at trauma from 4-11 years, mean 7.7 years) have been followed-up. MATERIAL AND METHODS: All patients were treated by custom-made arch bars and intermaxillary fixation for 12-17 days, then kept on a liquid diet for 15 days without fixation. The mean follow-up was 4.7 years. The conservative treatment has been evaluated with clinical, radiographic, and functional parameters. RESULTS: Remodelling of the condylar head was good in 17, whilst moderate remodelling occurred in the other four condyles. In four patients, a slight deflection (less than 2 mm) to the side of the fracture on wide mouth opening was seen. There was no malocclusion or ankylosis. CONCLUSION: Conservative treatment of condylar fractures during growth resulted in good function and good remodelling of the condyle. Functional treatment after intermaxillary fixation for 12-17 days proved to be quite acceptable.

Bone Remodeling↗
PubMed2000

Controlled release of terbinafine hydrochloride from pH sensitive poly(acrylamide/maleic acid) hydrogels.

Adsorption and controlled release of terbinafine hydrochloride (TER-HCl) to and from pH sensitive poly(acrylamide/maleic acid) (P(AAm/MA)) hydrogels were investigated. P(AAm/MA) hydrogels were prepared by irradiating the ternary mixtures of AAm/MA/and water by gamma-rays at ambient temperature. Antifungal drug, TER-HCl containing hydrogels, at different drug to polymer ratios, was prepared by direct adsorption method. The influence of MA content in the gel on the adsorption capacities of hydrogel and the effect of pH on the releasing behavior of TER-HCl from gel matrix were investigated. Terbinafine adsorption capacity of hydrogels are found to increase from 2 to 38 mg TER-HCl per g dry gel with increasing amount of MA in the gel system. In vitro drug release studies in different buffer solutions show that the basic parameters affecting the drug release behavior of hydrogel are the pH of the solution and MA content of hydrogel.

Acrylic Resins↗
PubMed2000

Effect of Valsalva maneuver on surface electrocardiographic P-wave dispersion in paroxysmal atrial fibrillation.

The purpose of this study was to investigate the effect of the Valsalva maneuver on P-wave durations and dispersion. After the Valsalva maneuver, we found that maximum P-wave duration increased, minimum P-wave duration decreased, and P-wave dispersion increased in controls, whereas the opposite was true for unselected patients with paroxysmal AF. It was concluded that patients with paroxysmal AF performing the Valsalva maneuver normalized their P-wave dispersion, thereby correcting the inhomogeneous intra-atrial conduction.

Anti-Arrhythmia Agents↗
PubMed2000

A clinical study on temporomandibular joint ankylosis.

OBJECTIVE: Temporomandibular joint (TMJ) ankylosis results from trauma, infection and inadequate surgical treatment of the condylary area. Many techniques for treatment have been described so far. However, none of them gave uniformly successful results. A limited range of intrinsical opening due to relapse, loss of vertical height of the affected ramus, foreign body reactions and reankylosis are expected complications. However, wide bone resection, the use of interpositional spacer, insensitive and aggressive physiotherapy immediately after the operation are the basic principles as agreed by many authors. In this article, a review of the historical background of the treatment has been discussed. METHODS: A clinical and retrospective evaluation of 42 patients treated for this disorder showed that 89% of all patients had unilaterally and 11% had bilateral ankylosis. From the viewpoint of the techniques we used, patients fell into three groups. In two groups, two different type of spacers were used, and in the third group gap arthroplasty were performed for the treatment of TMJ ankylosis. RESULTS: Our results revealed a predominance of traumatic aetiology. The highest incidence was between the ages of 11 and 20. A total of 45.24% of the patients were treated by interpositional arthroplasty by using acrylic spacer, 11.90% of the patients by sylastic sheet used as an interpositional material and the rest of the cases (42.86%) were treated only by gap arthroplasty. CONCLUSION: The advantages of the spherical acrylic spacer and gap arthroplasty were discussed. The advantages of the techniques are, shorter operating time, and more importantly its very low cost.

Adolescent↗
PubMed2000

The incidence of cysts and tumors around impacted third molars.

The objective of this retrospective analysis was to determine the incidence of the development of cysts and tumors around third molars and to discuss some relevant issues in relation to the removal of asymptomatic, impacted third molars. 9994 impacted third molars, removed in 7582 patients, formed the basis of this study. The analysis revealed 231 cysts (2.31%) and 79 tumors (0.79%), including 7 benign tumors (0.77%) and two malignant tumors (0.02%). The incidence of cysts and tumors around impacted third molars was 3.10%.

Adolescent↗
PubMed2000

Echocardiographic findings in professional league soccer players. Effect of the position of the players on the echocardiographic parameters.

BACKGROUND: The purpose of the study was to compare the echocardiographic parameters of soccer players to healthy controls and to assess the effect of the position of the soccer players on the echocardiographic findings. METHODS: M Mode 2D and Doppler echocardiographic examination were carried out on 83 professional league soccer players and 52 healthy controls. RESULTS: Soccer players had increased interventricular septum (1.14+/-0.13 cm vs 0.99+/-0.17 cm, p<0.001) left ventricular posterior wall (1.08+/-0.16 cm vs 0.91+/-0.13 cm, p<0.001) thickness, increased left ventricular diastolic diameter (5.24+/-0.40 cm vs 4.88+/-0.43 cm, p<0.001), volume (133+/-23 ml vs 113+/-22 ml, p<0.001) and increased left ventricular mass index (142+/-28 g/m2 vs 103+/-23 g/m2, p<0.001) compared to controls. Soccer players had greater mitral E wave to A wave ratio (2.08+/-0.53 vs 1.65+/-0.43, p<0.001) compared to controls. Soccer players were subgrouped according to their position in the play as goal keepers, defensive, midfielder, and offensive players. Comparison among defensive, midfield and offensive players revealed subtle differences between defensive and midfield players. Right ventricular dimensions were higher in goal keepers compared to midfielders due to the greater body surface area of the goal keepers (2.8+/-0.4 cm vs 2.4+/-0.5 cm, p<0.05). Left ventricle end diastolic dimension were similar between groups but when these dimensions were corrected for the greater height of the defensive players the difference between midfields and defensive players became significant (3.05+/-0.18 vs 2.89+/-0.22, p=0.05). On Doppler flow parameters the ratio of peak E wave to A wave velocity (2.27+/-0.55 vs 1.84+/-0.36, p<0.05) was increased in midfield players compared to defensive players. CONCLUSIONS: It was concluded that soccer players had greater left ventricular wall thickness, volume and mass compared to controls. But the effect of the position of the players on the measured cardiac dimensions were minimal. These subtle findings were explained by the leveling effect of the playing system and training, and lack of physical training during the previous month.

Adult↗
PubMed1999

An unusual treatment with sagittal split osteotomy: report of a case involving an odontoma.

Sagittal split osteotomy is one of the most commonly performed surgical techniques in the world and has been modified by many authors. The efficacy of this operation has been studied by many groups. When performing this surgery, there should be adequate contact of wide, cancellous bone surfaces, which guarantees excellent and rapid bony union in the desired position. In the present article, treatment of mandibular prognathism with open bite by sagittal split osteotomy with an odontoma in the third molar area is presented.

Adult↗
PubMed1998

Autonomic dysfunction in vitamin B12 deficiency: a heart rate variability study.

This study was arranged to examine whether vitamin B12 deficiency may cause autonomic dysfunction. Time-domain and long-term frequency-domain heart rate variability parameters from 12 patients with pernicious anemia were compared to 12 age and sex matched controls. In B12 deficient patient group time-domain parameters; SDNN (100.4 +/- 37.86 vs. 131.91 +/- 26.94, P = 0.05), SDANN (87.00 +/- 37.77 vs. 118.83 +/- 26.22, P = 0.05) SD (39.41 +/- 13.32 vs. 53.41 +/- 15.39, P = 0.0221), rMSSD (21.41 +/- 10.00 vs. 28.5 +/- 8.42, P = 0.046) were significantly lower when compared to controls. Difference in pNN50 between groups were not statistically significant. In B12 deficient patients frequency-domain parameters; total power (23.08 +/- 9.89 vs. 34.75 +/- 9.56, P = 0.0078), low frequency power (13.5 +/- 6.57 vs. 22.75 +/- 7.25, P = 0.0069) and high frequency power (7.58 +/- 4.25 vs. 11.58 +/- 3.80, P = 0.0175) were significantly lower when compared to controls. It was concluded that B12 deficiency may cause autonomic dysfunction.

Adult↗
PubMed1998

The effects of moclobemide on the yohimbine-induced anxiogenic action in the elevated plus-maze.

Moclobemide (MOC), a selective and reversible MAO-A inhibitor, was claimed to have both anxiolytic and anxiogenic properties. Therefore, we assessed whether: (1) acute and subchronic (10 days) MOC treatments, in doses which display antidepressant activity, affect the performance of rats in the elevated plus-maze that provides detection of both anxiolytic and anxiogenic properties in the same experimental conditions; (2) the alpha 2 antagonist yohimbine (YOH), which increases noradrenaline (NA) release, is able to modify the effects of MOC treatments in the elevated plus-maze. The results showed that MOC, at doses of 10 and 20 mg kg-1 i.p. either acutely or subchronically administered, significantly reduced the immobility time in the forced swimming test in rats. In other words, it displayed antidepressant activity. In the elevated plus-maze, acutely administered MOC (20 mg kg-1 i.p.) significantly increased both the percentage of open arm entries and the time spent in open arms, while only the former parameter was increased in response to 10 mg kg-1 i.p. MOC treatment. Thus, the anxiolytic action of MOC at a dose of 20 mg kg-1 i.p. was more prominent. Subchronically administered MOC at both doses significantly increased the two parameters. Hence, it can be stated that anxiolytic action of subchronically administered MOC appears to be more pronounced. Acutely administered YOH (0.5 mg kg-1 i.p.) showed anxiogenic effect in the elevated plus-maze. However, in both acutely and subchronically MOC-treated animals, YOH failed to exert its anxiogenic effect. This implies the importance of NA-gic activity in the MOC-induced anxiolytic action.

Adrenergic alpha-2 Receptor Antagonists↗
PubMed1998

A clinical study on oroantral fistulae.

The report presented is an analysis of 98 patients with an oroantral fistula (OAF). The tooth most frequently involved was the upper second molar, followed by the first molar. The highest incidence was seen in the fourth and third decades of life and the lowest incidence in the second decade. In this study, intercurrent sinusitis was the most obvious cause of the chronic oroantral communication. The closure of OAF is one of the more challenging problems in oral surgery. Long-term successful closure of OAF depends on the technique used, the size and location of the defect, and on the presence or absence of sinus disease. Among the several techniques proposed for treatment of OAFs, in the majority of cases, the buccal advancement flap technique was used in this study. The advantages and limitations of the technique are discussed.

Adolescent↗