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Biomedical subjects

H Uysal

Publications and source records attributed to H Uysal.

At least 19 recordsLinked to original sources
PubMed2005

An experimental analysis of stresses in simulated flared root canals subjected to various post-core applications.

Cervical root fracture is a major clinical problem in flared root canals treated with different post and core applications. This in vitro study evaluated the stress transfer of different post and core systems to the cervical part of the artificially created flared root canals, by using strain gauges. The post-core systems investigated were: (a) cast post-core system without resin reinforcement, (b) cast post-core system with resin reinforcement, (c) pre-fabricated post and resin core with resin reinforcement. The post-core systems which were cemented on simulated roots were subjected to a load applied at an angle of 45 degrees to the long axis of the simulated roots. The strain gauges which were cemented to the cervical part of simulated roots were connected to the data acquisition module to measure and record the changes in strain data. Specimens restored with resin reinforcement either with cast post-core or pre-fabricated post and resin core transferred the stress to the cervical part of the artificial roots at a rate lower than conventional cast post-core system (P = 0.001; anova and Tukey's post hoc test). It was concluded that the resin reinforcement of root canals before post-core applications reduces the stresses at the cervical part of the root surfaces.

Dental Restoration Failure↗
PubMed2004

The relationship between HRCT and pulmonary function in Behcet's disease.

The purpose of this study was to compare the pulmonary functions in female Behcet's patients with or without pathological pulmonary lesions using high resolution computerized tomography (HRCT). Twenty-nine female patients aged 19-54 yrs and 20 healthy females aged 19-50 yrs (control group) were accepted into the study. HRCT images were taken and according to HRCT patients were divided into HRCT (+) and HRCT (-) groups (18 patients in each). Pulmonary function tests (PFT) through a spirometer were performed and FVC, FEV(1), FEF(25-75%), PEF, VC, RV, FRC, DLCO and DLCO/VA were determined. No statistically significant difference was observed when the PFT values were compared between HRCT (+) and HRCT (-) patients for the obtained results and the percentage of the expected values. When the PFT values were compared for both HRCT (+) and HRCT (-) patients with the control group separately there was no statistical difference between the best values. A statistically low DLCO/VA value was observed between the percentage of the expected values. It is concluded that though there is a pulmonary restriction in Behcet's disease, this restriction has no relation to pulmonary functions. It would be useful to perform pulmonary function tests in the patients with Behcet's disease both with or without any pathological findings in HRCT for obtaining information about pulmonary functions. We suggest that even when the results of the pulmonary function tests are normal, considering some pathological changes in HRCT, HRCT investigations may be useful for following up the disease.

Adult↗
PubMed2002

Multiple plasma cell granuloma of the central nervous system: a unique case with brain and spinal cord involvement. Case report and review of literature.

STUDY DESIGN: Single subject (male, 34 years-of-age) case report. OBJECTIVES: To describe a unique case of plasma cell granuloma (PCG) with simultaneous brain and spinal cord involvement. SETTING: Private hospital, capital city, Turkey. METHODS: The patient presented with headache and paraplega. T2 weighted MR images showed multiple hyperintense cerebral, cerebellar, brainstem and spinal cord lesions that enhanced homogeneously with contrast medium. The patient was operated on, and the two intramedullary spinal cord lesions at T11 and T12 were totally excised. RESULTS: After 3 months of an intense physiotherapy programme the patient was able to walk with help. CONCLUSION: We report for the first time, the occurrence of multiple, simultaneous brain and intramedullary spinal cord plasma cell granulomas.

Adult↗
PubMed2001

Correlation between lead exposure indicators and sister chromatid exchange (SCE) frequencies in lymphocytes from inorganic lead exposed workers.

Inorganic lead exposure was studied in 31 volunteers employed in storage battery plant. The genotoxicity of lead was measured in terms of sister chromatid exchange (SCE). Erythrocyte delta-aminolevulinic acid dehydrogenase (ALAD) activity, urinary delta-aminolevulinic acid (U-ALA), and blood lead levels (PbBs) were also determined to evaluate some possible relations between these lead exposure indicators and the observed SCE frequencies. Blood lead concentration of 36.31 microg/dl was determined as an average level in the workers. Consequently decreased ALAD activity in erythrocytes and increased U-ALA excretion was observed in statistically higher PbBs when compared with the control group. A statistically significant correlation was observed between the PbBs and SCE frequencies (p < 0.05). Moreover, the correlation between U-ALA excretion and SCE frequencies (p < 0.01) was relatively higher than the correlation between PbBs and SCE frequencies. These results might indicate a possible mechanism of ALA mediation in the genotoxic effects of lead.

Adult↗
PubMed1999

Reproducibility of tendon jerk reflexes during a voluntary contraction.

OBJECTIVES: The present study explored whether testing tendon jerks during voluntary contraction of the test muscle would improve reproducibility by effectively 'clamping' the excitability of the motoneurone pool at firing threshold. METHODS: Tendon jerk reflexes of soleus, tibialis anterior and vastus lateralis and the soleus H reflex were recorded in 12 healthy subjects at rest and during voluntary contractions of 10-20% of maximum. Recordings were repeated 8-10 times in 5 subjects, in whom reflex symmetry was also determined. RESULTS: Not all tendon jerk reflexes could be recorded at rest, and the variability of latency and amplitude was high. All reflexes could be recorded in each subject during contractions. The latency of tendon jerk reflexes decreased by approximately 2 ms during contractions, but H-reflex latency decreased by only 0.2-0.3 ms. For the tendon jerks, an asymmetry of >3.0 ms at rest and >2.5 ms contracting would be outside 3 SD of the normal mean. In repeat studies, the coefficient of variation of reflex latency was <4% for the tendon jerk. CONCLUSIONS: A voluntary contraction could potentiate the tendon jerk by a number of mechanisms, but the most important is probably enhancement of the excitability of the motoneurone pool. The present techniques should increase the value of tendon reflex testing when assessing possible peripheral nerve, plexus and root disturbances.

Adult↗
PubMed1999

Changes in the expression and distribution of fibronectin, laminin and tenascin by cultured fibroblasts from skin lesions of patients with tuberous sclerosis.

Fibronectin, laminin and tenascin play an important part in the assembly of the extracellular matrix and the interaction of cells with it. In this study, changes in their expression and distribution associated with tuberous sclerosis are reported. Fibroblasts from three different tuberous sclerosis skin lesions (forehead plaque, neck fibroma and ungual fibroma) secreted more fibronectin and tenascin into their culture medium than did normal skin fibroblasts. Immunohistochemistry and flow cytometry showed that cells from an ungual fibroma which secreted most of each of these glycoproteins also retained more of them, associated mainly with the cell surface and a perinuclear area. Laminin was also produced by all fibroblasts but only in those from the neck fibroma was more both secreted and retained. The proportions of fibronectin/laminin/tenascin secreted by the skin lesion fibroblasts were markedly different from normal. The results suggest that the characteristic tissue hardening of skin lesions in tuberous sclerosis may result, at least in part, from differences in the expression and distribution of these critical components of the extracellular matrix and its consequent abnormal assembly.

Adolescent↗
PubMed1999

Cerebrospinal fluid nitric oxide levels in childhood bacterial meningitis.

The role of nitric oxide (NO) in childhood bacterial meningitis was investigated by determining the levels of nitrate/nitrite, stable end products of NO metabolism, in cerebrospinal fluid (CSF). Eighteen children with bacterial meningitis and 18 as a control group were included in the study. Mean (+/- SD) CSF nitrate/nitrite levels were 27.6 +/- 26 micromol/l in the bacterial meningitis group and 3.2 +/- 1.8 micromol/l in the control group (p = 0.0005). We found no correlation between CSF nitrate/nitrite levels and CSF white blood cell count (r = 0.22), protein (r = 0.26) or tumour necrosis factor alpha (TNF-alpha) levels (r = 0.046), but a moderate negative correlation between CSF nitrate/nitrite and glucose levels (r = -0.46).

Adolescent↗
PubMed1999

Babinski reflex by sural stimulation and dysfunction of descending motor pathway.

The aim of the study was to find out the relationship between the Babinski reflex and flexor polysynaptic reflexes which was evaluated by sural nerve stimulation, and to evaluate the descending motor pathway in involvement by cervical and transcortical cranial stimulation (TCCS) in a group of patients that were diagnosed as having the Babinski sign with either hemiparetic of hemiplegic, due to a cerebrovascular accident. In the normal population no significant responses were seen from the EHL by sural stimulation and these responses were recorded from the BF with a latency of 88 msec. In the patients who had Babinski reflex responses, signs could be easily recorded from EHL by sural stimulation with a latency of 166 msec. In this group, reflex responses from the BF were recorded with a latency of approximately 100 msec. Responses from the EHL were evaluated in 100% ratio by TCCS with a latency of 33.4 msec. in the normal group. The responses recorded from EHL by TCCS and latency was 47.5 msec. in 35.7% of the patients, who having Babinski sign. In 100% of the normal population, responses were evaluated with a latency of 28.8 msec. from EHL by cervical stimulation. In only 55% of the patients having the Babinski sign, responses were recorded in the same limb with a latency was 32.3 msec. These results support a different mechanism that control the EHL muscle in comparison to the BF muscle having dysfunction of descending motor tracts due to a pyramidal lesion.

Adult↗
PubMed1998

Pulmonary function of workers in the aluminum industry.

The effects of aluminum on the pulmonary function of aluminum workers were investigated in this study. Serum aluminum levels and spirometry were measured in 55 male workers and 30 male controls. The mean serum aluminum level of workers (72.7 +/- 9.9 ng/ml) was significantly high compared to that of controls, indicating aluminum toxicity. Spirometric parameters were significantly lower in workers than in controls and correlated negatively with both exposure time and serum aluminum levels. The impairment in pulmonary function may be due to exposure time and insufficient protection.

Adult↗
PubMed1998

Comparison of four different denture cushion adhesives--a subjective study.

Four cushion adhesives (Fittydent I; Fittydent II, introduced as an advanced formula; Protefix; and Seabond) were compared clinically through patients subjective evaluations. Maxillary dentures of 32 patients were relined and the mandibular dentures were scored by Kapur index before the application of different treatments. The cushion adhesives were used only with the existing mandibular prosthesis. The four treatments were applied to the patients in groups of 8 by allocating each group randomly to one of the four sequences of treatments determined by latin square design. Each patient took each treatment only once. The adhesives were applied by the authors as recommended by the manufacturers. Patients used each material for 24 h and, through a questionnaire, they evaluated the seven following aspects of each different cushion material: retention, duration of retention, effects on ability to chew, effects on other oral functions, cleansing of dentures, cleansing of gums, and an overall evaluation of materials. Both Fittydent products significantly improved denture retention and the ability to chew. The patients who expressed 'much better' chewing with Fittydent products, had mandibular dentures rated poor or fair.

Adhesives↗
PubMed1997

Changes in the secretion and glycosylation of fibronectin by human skin fibroblasts associated with tuberous sclerosis.

Fibroblasts from skin and skin lesions of patients with tuberous sclerosis (TS) and from skin of normal individuals were grown in culture. ELISA showed that the spent medium of those derived from TS skin lesions contained significantly more fibronectin (FN) than spent medium from the other cells. Amino acid compositional analysis of the FN from TS and normal sources revealed no substantial differences. However the FN of fibroblasts from TS-skin lesions was shown by HPAEC to contain a two- to three-fold increased content of carbohydrate. The changed monosaccharide composition was consistent with an increased content of N- and O-linked glycans and with the former containing polylactosamine chains. Fibroblasts from a normal individual were shown to proliferate more slowly and to produce larger cells when grown on FN from a TS skin lesion compared to growth on FN from normal skin.

Adolescent↗
PubMed1996

Antiseizure activity of insulin: insulin inhibits pentylenetetrazole, penicillin and kainic acid-induced seizures in rats.

The present study was undertaken to evaluate the antiseizure activity spectrum of insulin against various behavioral seizure models in rats. Insulin was injected intraperitoneally (i.p.) at a test dose of 1 U/kg. Dextrose (3 g/kg) was administered simultaneously with insulin to counteract its hypoglycemic effect and induce a normoglycemic state. Insulin was found to significantly decrease the incidence, intensity and mortality rate and prolong the latency of generalized tonic-clonic convulsions induced by pentylenetetrazole (60 mg/kg i.p.) and significantly decrease the intensity and mortality rate and prolong the latency of generalized tonic-clonic convulsions induced by penicillin (2000 U/intracerebrocortical). Insulin was not only found to prolong the latency of all the seizure components but was found to reduce the incidence of focal myoclonic twitches and generalized tonic-clonic convulsions induced by kainic acid (12 mg/kg i.p.) as well. Insulin was shown to be ineffective to suppress ouabain (5 micrograms/intracerebroventricular) induced seizures. These findings indicate that insulin possesses a broad spectrum of antiseizure activity in rats. Interaction with brain Na(+)-K(+)-ATPase has been discussed as a possible mechanism of action.

Animals↗
PubMed1996

Vagal stimulation.

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Efferent Pathways↗
PubMed1996

Determination of the heart rate deflection point by the Dmax method.

OBJECTIVE: Conconi et al. proposed that the point where heart rate departed from linearity in an incremental exercise test was a good indicator of the anaerobic threshold. However, the heart rate deflection points (HRDPs) can not be determined in many subjects. The aim of this study was to determine the heart rate deflection point by the Dmax method and to compare it with the conventional linear method. SETTING: The study was performed in the Exercise Physiology Laboratory in the Faculty of Medicine, Selçuk University. PARTICIPANTS: Thirty-two untrained males (aged 18-22) performed a maximal exercise test on a cycle ergometer. RESULTS: The deflection from linearity of HR could not be detected in nine subjects (28%) by the linear method. The HRDPs could be detected in all subjects by the Dmax method. It was observed that the HR values in the HRDPs determined by both methods were close to the maximal HR values (approximately 90% of maximum). There were high correlations and no differences (p more than 0.05) between the deflection points expressed as oxygen uptake, HR and work rate determined by two methods (correlation coefficients 0.93, 0.93, 0.97, respectively, p less than 0.001). CONCLUSIONS: The Dmax method is more useful than linear method. The HRDPs of all the people can easily and objectively be found by this method.

Adolescent↗