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Biomedical subjects

S Ozden

Publications and source records attributed to S Ozden.

52 records · Page 3Linked to original sources
PubMed1990

Isolation of a specific cellular mRNA by subtractive hybridization in Theiler's virus persistent infection.

Viruses change the mRNA repertoire of the tissues they infect. They add viral mRNAs and they specifically alter the expression of some host genes. These events can play important parts in pathogenesis. In principle, it should be possible to isolate viral mRNAs and to identify changes in host gene expression using subtractive hybridization. We tested this approach in the persistent infection of mouse central nervous system by Theiler's virus. A cDNA library was constructed with poly A+ RNA from infected mouse spinal cords. The library was screened with a subtracted probe. We identified one mitochondrial gene, coding for subunit 1 of cytochrome oxidase, which is overexpressed in infected tissues whereas another mitochondrial gene, URF 2, is not. Subtractive hybridization should prove to be invaluable in studying the pathogenesis of chronic human central nervous system diseases of unknown etiology.

Animals↗
PubMed1990

Simultaneous in situ detection of two mRNAs in the same cell using riboprobes labeled with biotin and 35S.

We used 35S-labeled and biotinylated cRNAs (riboprobes) to detect simultaneously two different mRNAs by in situ hybridization. In a first step we established the conditions under which each type of probe achieved the same high level of sensitivity. We then used these conditions to hybridize BHK cells infected with Theiler's virus, a murine picornavirus, with a mixture of a virus-specific biotinylated riboprobe and a 35S-labeled riboprobe specific for beta-actin mRNA. Both mRNAs could be detected in the same cell, although the sensitivity achieved by the radiolabeled probe was reduced by about 40% by the simultaneous hybridization with the biotinylated probe.

Actins↗
PubMed1988

Expression of Theiler's murine encephalomyelitis virus protease 3C and polymerase 3D in Escherichia coli and characterization of monospecific sera.

Defined DNA fragments of cloned Theiler's murine encephalomyelitis virus genome were used to construct procaryotic recombinant plasmids expressing viral genes 3C and 3D. In these plasmids (pEX-EMBL vectors), viral sequences are fused in-phase behind the Escherichia coli lac Z' gene which is under the control of the inducible lambda Pr promoter. Partially purified fusion proteins were used to immunize Balb/c mice. Sera monospecific for the viral protease 3C and polymerase 3D were obtained. These sera detected their corresponding antigens in situ in infected BHK cells using immunocytochemical reactions.

3C Viral Proteases↗
PubMed1986

Theiler's virus genome is closely related to that of encephalomyocarditis virus, the prototype cardiovirus.

Theiler's virus causes a persistent demyelinating infection of the mouse central nervous system. Our study of the molecular mechanism of persistence led us to sequence 1925 nucleotides located at the 3' end of the viral genome. We observed extensive homologies between this region and the corresponding region of encephalomyocarditis virus, the prototype cardiovirus, and only some homologies with the 3' ends of foot-and-mouth disease virus, rhinovirus, and poliovirus genomes.

Amino Acid Sequence↗
PubMed1985

Dengue virus induced polypeptide synthesis. Brief report.

Dengue 2 virus polypeptide synthesis was investigated in BHK21 cells. Nine or ten virus induced polypeptides were identified, three of which are glycoproteins as demonstrated by tunicamycin treatment of infected cells. We performed pulse chase experiments, experiments with amino-acid analogs, protease inhibitors or pactamycin treatment of infected cells, to determine whether or not large polypeptide processing occurs. In some of these experiments a large polypeptide (P 130) was immunoprecipitated by an anti-dengue 2 serum. We observed a transfer of label between small molecular weight polypeptides which might be the result of restricted proteolytic cleavage.

Animals↗
PubMedDate not supplied

Effect of trimetazidine on retinal ischemia/reperfusion injury in rats.

PURPOSE: To investigate the effect of trimetazidine (TMZ), an antioxidant agent, on the ischemia/reperfusion (I/R) injury in rat retina histopathologically. METHODS: The retinal I/R model was carried out by the 4-vessel occlusion method on Wistar albino rats. Twenty-one rats were divided into 7 groups, each comprising 3 rats. The animals in groups 1, 2 and 3 underwent 30 min of ischemia + 4 h of reperfusion and were treated by the administration of saline, TMZ before reperfusion and TMZ before ischemia, respectively. The animals in groups 4, 5 and 6 underwent 90 min of ischemia + 4 h of reperfusion and were treated in the same way as those in groups 1, 2 and 3, respectively. The 7th group was sham operated. RESULTS: Thirty and 90 min of ischemia followed by 4 h of reperfusion induced retinal injury in the rat retina. Histopathologically, the inner plexiform and inner nuclear layers were the most affected parts. TMZ was able to reduce almost all retinal I/R damage when administered before ischemia. A cytoprotective effect of TMZ was partly observed in those animals which were treated before reperfusion. CONCLUSION: TMZ seemed to have a protective effect against retinal I/R injury in rats.

Animals↗
PubMedDate not supplied

Protective effects of antithrombin III on retinal ischemia/reperfusion injury in rats: a histopathologic study.

PURPOSE: To investigate the effect of antithrombin III (AT III) on retinal ischemia/reperfusion (I/R) injury in rats. METHODS: The study was carried out on 10 Wistar albino rats (20 eyes) and four-vessel occlusion method was employed to induce retinal ischemia in this study. Rats were divided into two groups: Group I (control group, 10 eyes) and Group II (AT III, 10 eyes). In both groups, vertebral arteries were occluded bilaterally an electric needle coagulator under an operating microscope. A total of 48 hours after the initial procedure, the rats were re-anesthetized and both common carotid arteries were clamped to interrupt blood flow. In Group II, rats were injected intravenously with 250 U/kg of AT III 5 minutes before the induction of ischemia. Duration of ischemia was 30 minutes. At the end of this period, clamp was removed for the reperfusion of the eye for 4 hours. Following the reperfusion period, the animals were killed by decapitation. Retinal sections were evaluated under light and electron microscope. The signs of I/R injury at the microscopic level, i.e., cellular degeneration, vacuolization between retinal layers, increase in the retinal thickness due to edema, mononuclear cell infiltration, and apoptotic cells, were recorded for each group. RESULTS: Retinal sections obtained from the rats in the AT III group revealed a well preserved retinal structure. When average thickness values of the two groups were compared to each other, the difference was significant with respect to inner nuclear and inner plexiform layers indicating increased retinal thickness values in Group I due to tissue edema resulting from I/R injury. Similarly, mononuclear cell infiltration and apoptotic cell counts were found to be significantly higher in control group compared to AT III group showing the inhibitory effect of AT III on leukocyte infiltration and apoptotic cell death in rat retina. CONCLUSIONS: Antithrombin III attenuated I/R injury in rat retina.

Animals↗
PubMedDate not supplied

In vitro tuberculostatic activities of some 2-benzylbenzimidazole and 2-phenoxymethylbenzimidazole derivatives.

Some 2-benzylbenzimidazole and 2-phenoxymethylbenzimidazole derivatives were synthesized and tested for in vitro tuberculostatic activity against Mycobacterium tuberculosis H 37 Rv. and human type wild strain (protocol n degrees.4186). The synthesized compounds have one of the CH3, Cl, NO2 or OCH3 groups at position 5 and 4' and are prepared by heating appropriate o-phenylenediamines with the carboxylic acids in the presence of 4.5N HCl. The experiments indicate that 2-phenoxymethylbenzimidazoles were more active than the corresponding 2-benzylbenzimidazoles. The most active compound was 5-chloro-2-phenoxymethylbenzimidazole (IIc) (MIC: 125 micrograms/ml).

Antitubercular Agents↗
PubMedDate not supplied

Tay-Sachs disease: a case report.

Tay-Sachs disease (GM2 gangliosidosis I) is an autosomal recessive lysosomal-storage disorder confined to the central nervous system, resulting from deficiency of hexosaminidase A. The case presented is of a twelve-month-old girl brought to the hospital because of mental-motor deterioration and convulsions. She was the child of first cousins and had a history of the deaths of two siblings with the same manifestations. Generalized hypotonia, macrocephaly, hyperacusis and a retinal cherry red spot appearance were present. There was no organomegaly. The diagnosis of Tay-Sachs disease was made by means of absence of serum hexosaminidase A activity.

Age of Onset↗
PubMedDate not supplied

The number of follicles and ovarian volume in the assessment of the response to clomiphene citrate in polycystic ovarian syndrome.

OBJECTIVE: To evaluate whether the number of follicles and ovarian volume have any significance in evaluating the response to clomiphene citrate treatment in Polycystic ovarian syndrome (PCOS). DESIGN: A prospective study of 70 infertile women, 44 of which were diagnosed with PCOS. SETTING: Zeynep Kamil Women and Children's Hospital Infertility Polyclinic. MAIN OUTCOME MEASURES: Follicle numbers and volumes in both ovaries, hormonal profile, response to Clomiphene Citrate (CC). Ovarian volume was significantly greater in PCOS cases than controls. However ovarian volume in the CC nonresponders was significantly greater than in CC responders in the PCOS group. The number of small follicles was significantly higher in PCOS cases than controls, and in the CC nonresponder group this number was also significantly higher than in CC responders. Endocrine features of patients with PCOS revealed that FSH, LH/FSH, DHEAS and Androstenedion do not discriminate between patients who respond to CC and those who do not respond. However, Testosterone (T) and LH levels differ significantly in responders and nonresponders. Small multiple follicles (> 9) and enlarged ovarian volume (> 6.8 ml) were the most prominent transvaginal ultrasonographic features of ovaries in CC nonresponsive patients with PCOS. Higher levels of T, LH, and significantly higher number of small follicles were associated with lack of CC response. These ultrasonographic features and laboratory assays could be clinically useful for distinguishing better the CC nonresponders from responders.

Adult↗