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Biomedical subjects

S Ozden

Publications and source records attributed to S Ozden.

At least 37 records · Page 2Linked to original sources
PubMed1998

The significance of birth weight difference in discordant twins: a level to standardize?

OBJECTIVE: To evaluate the significance of different degrees of birth weight discordance in twin pregnancies. DESIGN: Population based study. METHODS: Three hundred and eighty-four twin gestations over 20 weeks of gestation during a two-year period ending in 31.12.1995 were retrospectively analyzed. Twins were stratified into six categories according to the percent difference in infant birth weight. The difference in percents was calculated from the larger twin; (Birth weight of larger twin--Birth weight of smaller twin)/Birth weight of larger twin and multiplied with 100. The relationship between different categories and the subsequent perinatal and neonatal outcomes was assessed. RESULTS: Among 384 pairs thirteen patients were identified to have single fetal demise and fourteen patients were documented to have dead fetuses of both twin pairs. Of 357 twin gestations studied 137 (38.4%) had discordance of < 10% and 36 experienced discordance of > 30% (10.1%). The frequency of low APGAR score (< 7) in women with > 30% discordance was higher than that of < 10% group (16.7% vs. 9.5%). Intensive care for infants was required in 30 infants with > 30% birth weight discordance (41.7%) and in 24 cases with < 10% birth weight discordance (8.8%). Thirty-three percent of cases with discordance of > 30% experienced neonatal mortality whereas the corresponding figure for patients with < 10% discordance was 1.5%. CONCLUSION: We postulate that definition of discordant growth in twin gestations should be categorized with respect to gestational week since the level of discordance prejudicing fetal or neonatal jeopardy may vary in different stages of pregnancy.

Adult↗
PubMed1997

Infection of choroid plexus cells by human T cell leukaemia virus type I.

Very little is known about the factors that determine the outcome of infection by human T cell leukaemia virus type I (HTLV-I) and the neurotropism of this virus is still a controversial point. In transgenic mice, the HTLV-I LTR is active mainly in the central nervous system (CNS), in parenchyma as well as in ependymal and choroid plexus cells. The latter are of particular interest and could represent the way of entry of the virus into the CNS. In this study we show that primary cultures of sheep choroid plexus can be infected with HTLV-I, leading to characteristic multinucleated syncytial cells containing virus RNA and proteins. HTLV-I p24 Gag protein was detected in the culture medium and the presence of virus particles was observed by electron microscopy 40 days after infection. At this time post-infection HTLV-I could be transmitted to human cord blood cells.

Animals↗
PubMed1997

Random selection: a model for poliovirus infection of the central nervous system.

Mixed infections occur in the natural environment, and also result from the use of mixed live vaccines. Some recipients of the trivalent oral poliovirus vaccine develop vaccine-associated paralytic poliomyelitis (VAPP). Numerous serotypes and recombinant genotypes of vaccine-derived polioviruses may be found in stool samples from such cases. To investigate the relationship between the multiplication of various genotypes at the primary replication site in the gut and the infection outcome in the central nervous system (CNS), the viruses excreted on consecutive days by two patients with VAPP were compared with the viruses isolated from the CNS. The genotypes from stools were numerous and varied with time in both cases, suggesting a multiplication of the viruses in multiple foci in the gut. Where the CNS isolated virus clearly corresponded to one of the many viruses detected in stool, this virus was unexpectedly less neurovirulent than others isolated from stool. To assess the mechanism by which viruses with different degrees of neurovirulence are selected in the CNS, transgenic mice sensitive to poliovirus infection were inoculated extraneurally with mixtures of two phenotypically different viruses at different neuropathogenic doses. The virus(es) inducing neurological disease was then isolated from the CNS. At less than 100% input neuropathogenic dose of both inoculated viruses, individual mice were affected stochastically by the virus variants from the mixture. Extrapolated to humans, this selection pattern might explain the occurrence of CNS infections with less neurotropic viruses derived from an extraneural pool containing also highly neurotropic viruses.

Animals↗
PubMed1996

Reproductive outcome after metroplasty.

OBJECTIVE: To evaluate the impact of abdominal metroplasty for symmetric uterine anomalies on reproductive performance. METHOD: A retrospective analysis of 24 patients who conceived following metroplasty for symmetric congenital anomalies during a 5-year period. RESULTS: In patients with poor obstetric histories before surgery, the overall fetal survival rate increased from 2.5%, before treatment to 73.3% after treatment and 90.5% of women gave birth to a surviving infant. The remaining three patients suffering from infertility delivered a full-term infant after metroplasty. Antenatal complications occurred in 56.7% of the pregnancies. CONCLUSION: Abdominal metroplasty clearly improves fetal survival particularly in women suffering from a history of poor obstetric outcome associated with symmetric malformations.

Abortion, Spontaneous↗
PubMed1996

Acylated delphinidin glycosides in the blue-violet flowers of Consolida armeniaca.

Four new acylated delphinidin 3,7-glycosides were isolated from the blue-violet flowers of Consolida armeniaca as major anthocyanin pigments. The first pigment was based on delphinidin 3,7-diglucoside and was identified as delphinidin 3-O-[6-O-(malonyl)-beta-D-glucopyranoside]-7-O- [6-O-(4-O-(6-O-(p-hydroxybenzoyl)-beta-D-glucopyranosyl)-p-hydroxybenzoy l)- beta-D-glucopyranoside] by spectral methods. The other three acylated anthocyanins were based on delphinidin 3-glucoside-7-sophoroside. The second pigment was determined to be delphinidin 3-O-[6-O-(malonyl)-beta-D-glucopyranoside]-7-O-[2-O-(beta-D- glucopyranosyl)-6-O-(4-O-(6-O-(p-hydroxybenzoyl)-beta-D-glucopyranosyl)- p- hydroxybenzoyl)-beta-D-glucopyranoside]. The third pigment was elucidated to be delphinidin 3-O-[6-O-(malonyl)-beta-D-glucopyranoside]-7-O-[2-O-(6-O-(p- hydroxybenzoyl)-beta-D-glucopyranosyl)-6-O-(4-O-(6-O-(p-hydroxybenzoyl)- beta-D- glucopyranosyl)-p-hydroxybenzoyl)-beta-D-glucopyranoside], and the fourth as delphinidin 3-O-[6-O-(malonyl)-beta-D-glucopyranoside]-7- O-glucopyranosyl[(2-O-(6-O-(p-hydroxybenzoyl)-beta-D-glucopyranosyl)-6-O - (4-O-(6-O-(p-hydroxybenzoyl)-beta-D-glucopyranosyl)-p-hydroxybenzoyl)-be ta-D- glucopyranoside].

Acetylation↗
PubMed1996

HTLV-I transgenic models: an overview.

Human T cell leukemia virus type I (HTLV-I) is the agent of a wide spectrum of human diseases. The mechanisms by which a single virus can cause neurodegenerative disorders as well as leukemia is still a matter of debate. Transgenic mice have been used to assess the contribution of different viral elements in viral tropism as well as on cell transformation in vivo. In particular, transgenic models were generated to study the tissue specificity of expression directed by the viral long terminal repeat and the pathological effects induced by the Tax protein of HTLV-I. These models have led to a description of the cell types able to support the viral expression in vivo, and the use of Tax-transgenic mice has demonstrated that this protein is oncogenic and able to induce muscular atrophy and arthropathies. Finally, these models could provide a useful system to study therapeutic approaches for HTLV-I-associated diseases.

Animals↗
PubMed1996

The number of follicles and ovarian volume in the assessment of response to clomiphene citrate treatment 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 polycystic ovarian syndrome. MAIN OUTCOME MEASURES: Follicle numbers and volumes in both ovaries, hormonal profile, response to Clomiphene Citrate(CC). RESULTS: Ovarian volume was significantly greater in cases with polycystic ovarian syndrome than controls. However, ovarian volume in the Clomiphene Citrate nonresponders was significantly greater than in Clomiphene Citrate responders in the polycystic ovarian syndrome group. The number of small follicles was significantly higher in cases with polycystic ovarian syndrome than controls, and in the Clomiphene Citrate nonresponder group this number was also significantly higher than in Clomiphene Citrate responders. Endocrine features of patients with polycystic ovarian syndrome revealed that Dehydroepiandrostenedione sulfate, Androstenedione, follicle stimulating and luteinizing hormone do not discriminate between patients who respond to Clomiphene Citrate and those who do not respond. However, Testosterone and luteinizing hormone levels differ significantly in responders and nonresponders. CONCLUSIONS: Small multiple follicles (> 9) and enlarged ovarian volume (> 6.8 ml) were the most prominent transvaginal ultrasonographic features of ovaries in Clomiphene Citrate nonresponsive patients with polycystic ovarian syndrome. Higher levels of Testosterone, luteinizing hormone and significantly higher number of small follicles were associated with lack of Clomiphene Citrate response. These ultrasonographic features and laboratory assays could be clinically useful for distinguishing better the Clomiphene Citrate nonresponders from responders.

Adult↗
PubMed1996

Analysis of the expression directed by two HTLV-I promoters in transgenic mice.

We generated several lines of mice transgenic for the lacZ reporter gene under the control of an HTLV-I LTR. Two different LTR were used; one was isolated from a case of Adult T-cell Leukemia (ATL), the other from a case of Tropical Spastic Paraparesis (TSP/HAM). These LTR differed at 18 nucleotide positions. The pattern of expression of the transgene, studied at the RNA level by RT-PCR, was the same regardless of the origin of the promoter. The beta-galactosidase activity was detected primarily in the central nervous system, in the parenchyma, the choroid plexus and the ependymal cells along the ventricles. In parenchyma, double labelling experiments showed that the cells expressing beta-galactosidase were neurons. These results show that choroid plexus cells and ependymal cells, as well as some neurons, are permissive for the activity of the HTLV-I promoter. The origin of the LTR had not influence on the pattern of expression of the reporter gene.

Animals↗
PubMed1996

QSAR analysis of a set of benzimidazole derivatives based on their tuberculostatic activities.

A set of benzimidazole derivatives previously tested for their tuberculostatic activities was analyzed using the quantitative structure activity relationship (QSAR) method. The activity contributions for structural and substituent effects were determined from the correlation equations which were derived using stepwise regression technique. The resulting QSAR showed that the activity contributions of benzimidazoles depend on the size of the substituents at R2, the field effect of the substituents at R1 and structural parameter IY which indicates the presence of oxygen between the benzimidazole and benzyl or phenyl groups.

Antitubercular Agents↗
PubMed1995

A search for human T-cell leukemia virus type I in the lesions of patients with tropical spastic paraparesis and polymyositis.

We searched for the presence of human T-cell leukemia virus type I (HTLV-I) sequences in central nervous system and muscle lesions of 3 patients with tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM) and 3 patients with HTLV-I-associated polymyositis. Proviral DNA coding for the Tax protein was found by polymerase chain reaction amplification in DNA extracted from lesions of every patient with TSP/HAM or HTLV-I-associated polymyositis. In contrast, viral RNA was found occasionally by in situ hybridization in muscle lesions of some patients with polymyositis, but was never found in central nervous system lesions of TSP/HAM patients.

DNA, Viral↗
PubMed1995

IgG autoantibody response in HTLV-I-infected patients.

Human T-cell leukemia virus type I (HTLV-I) is associated with a large spectrum of clinical manifestation including adult T-cell leukemia (ATL) and tropical spastic paraparesis or HTLV-I-associated myelopathy (TSP/HAM). In most cases, however, infected patients remain asymptomatic. The participation of the immune system in the pathogenesis of TSP/HAM has been suggested. In this study the IgG antibody response of HTLV-I-infected individuals has been investigated using both ELISA with a panel of nuclear and cytoplasmic proteins and peptides known to be recognized by antibodies from patients with various systemic autoimmune diseases, and immunoprecipitation of ribonucleoproteins from HeLa cell extracts. The results were compared with the reactivity of sera from individuals with non-HTLV-I-related neurological diseases and healthy blood donors. Raised levels of autoantibodies reacting with several nuclear and cytoplasmic antigens were found in TSP/HAM and ATL patients. In asymptomatic HTLV-I-seropositive individuals, both the prevalence and level of IgG antibodies were lower and directed only against a restricted set of antigens. The mechanism of induction of these antibodies still remains obscure. However, the results show that a significant autoimmune response exists in these patients and it may contribute to the pathogenesis of the disease.

Adult↗
PubMed1993

Analysis of proteolipid protein and P0 transcripts in mice infected with Theiler's virus.

Inbred strains of mice vary in their susceptibility to the chronic inflammatory and demyelinating disease caused by Theiler's virus. The severity of this disease depends on the extent of demyelination but also on the occurrence of remyelination. We studied the extent of demyelination and remyelination in mice with different genetic backgrounds. To estimate the extent of demyelination, we analyzed the abundance of proteolipid protein (PLP) transcripts in the spinal cord 45 days after inoculation. RNA transcripts were quantitated at the single cell level using in situ hybridization. We observed a correlation between the reduction of PLP mRNA and the extent of inflammation in the SJL/J, C3H, F1 SJL x C3H and C3H.Q strains. Remyelination by Schwann cells was estimated by the detection of P0 mRNA and was observed in C3H mice only. It is likely that intense inflammation in highly susceptible strains prevents the migration of Schwann cells into the central nervous system (CNS).

Animals↗
PubMed1993

Comparative analysis of HTLV-I promoter activities reveals no disease-linked pattern of expression.

To investigate the possibility of an association between the type of pathology caused by HTLV-I and the activity of its promoter, we compared the levels of transcription obtained with six LTRs isolated from patients with two different HTLV-I-related diseases: ATL and TSP/HAM. The patients came from different geographical endemic areas. The LTR region was amplified by polymerase chain reaction (PCR) from the DNA of uncultured peripheral blood lymphocytes, and directly cloned upstream of the luciferase reporter gene. Constructs were tested by a transient transfection assay in a variety of cell lines. Although the activities of these LTRs were statistically different in some of the cell lines tested, no correlation could be demonstrated between the promoter activity and the nature of the disease. Thus, the data suggest that the LTR is not a major determinant of the nature of the disease associated with the infection by HTLV-I.

Analysis of Variance↗
PubMed1993

Comparison of the sensitivities of ribonucleic acid and oligonucleotide probes for in situ detection of Theiler's virus mRNA.

To evaluate the sensitivity of in situ detection of the Theiler's virus genome, we hybridized BHK-21-infected cells with antisense ribo- and oligonucleotide 35S-labeled probes. The sensitivity achieved with the anti-sense 280-nucleotide riboprobe was similar to that obtained with a 93-mer oligonucleotide probe. However, more reproducible and accurate results were obtained with the riboprobe. With long exposure times, the background was higher with the oligonucleotide probe than with the RNA probe. The background was improved by using freshly labeled oligonucleotide probe.

Animals↗
PubMed1992

Functional analysis of two long terminal repeats from the HTLV-I retrovirus.

Human T-cell leukemia virus type I (HTLV-I) is associated with a large spectrum of clinical manifestations in man. Viral and host factors are probably involved in determining the consequences of infection. Although most of the genome of HTLV-I appears remarkably stable, considerable variation is observed in the long terminal repeat (LTR) which harbors the promoter region. So far, no correlation between specific mutations and pathogenesis has been found, and the current opinion is that sequence variations reflect the geographical origin of the isolate more than the associated pathology. To assess whether the mutations observed between two HTLV-I LTRs were functionally significant, two LTRs, which differ by ten mutations, were coupled to the highly sensitive eukaryotic luciferase-encoding reporter gene, luc, and tested by transfection in a variety of cell lines. Marked differences in promoter activity were observed in some of the cells tested, whereas in other both LTRs were equally active. This result demonstrates that the minor differences observed between two HTLV-I LTRs can affect the activity level of the promoter in some cellular environments, a result which could point to the LTR as one determinant of HTLV-I cell tropism in vivo.

Animals↗
PubMed1992

Tissue expression pattern directed in transgenic mice by the LTR of an HTLV-I provirus isolated from a case of tropical spastic paraparesis.

Human T lymphotropic virus type I (HTLV-I) causes adult T cell leukemia/lymphoma and a chronic neurological disease called either tropical spastic paraparesis (TSP) or HTLV-I-associated myelopathy. The different outcomes of this infection could be due to both host and viral factors and it has been proposed that genetic differences could make some HTLV-I strains neurotropic. In this paper, we examined the pattern of tissue-specific expression determined by a long terminal repeat (LTR) obtained from a case of TSP. We constructed transgenic mice in which this LTR controlled the expression of the nlslacZ reporter gene. We observed that in three independent lines of transgenic mice, the reporter gene was expressed predominantly in the central nervous system (CNS), in choroid plexus, and in cells of the hippocampus and cerebellum. Our observations indicate the existence of CNS cells permissive for the expression of HTLV-I and which may be of importance in the pathogenesis of TSP.

Animals↗
PubMed1991

In situ analysis of proteolipid protein gene transcripts during persistent Theiler's virus infection.

SJL/J mice inoculated intracranially with the DA strain of Theiler's virus exhibit a persistent demyelinating disease of the central nervous system. To investigate the effect of persistent infection of oligodendrocytes on the expression of myelin genes, we analyzed the level of PLP mRNA in infected as well as uninfected oligodendrocytes. This study was performed at the single-cell level using the simultaneous detection of viral antigens by immunocytochemistry and PLP mRNAs by in situ hybridization with 35S-labeled oligonucleotide probes. Our data indicate that viral infection of oligodendrocytes reduces the level of PLP mRNA by about 80%.

Animals↗