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Biomedical subjects

G Yavuz

Publications and source records attributed to G Yavuz.

At least 19 recordsLinked to original sources
PubMed2002

657del5 mutation in the NBS1 gene is associated with Nijmegen breakage syndrome in a Turkish family.

We report on a consanguineous Turkish family whose first son died of anal atresia and whose second son presented with severe pre- and post-natal growth retardation as well as striking microcephaly, immunodeficiency, congenital heart disease, chromosomal instability and rhabdomyosarcoma in the anal region. The proband was found to carry the homozygous 657del5 mutation in the NBS1 gene, which is responsible for Nijmegen breakage syndrome (NBS) in most of the Slav populations. Our family, the first diagnosed with NBS in the Turkish population, represents one of the most severely affected examples of the syndrome, with profound pre- and post-natal growth retardation associated with structural abnormalities, and expands the clinical spectrum of this rare disorder.

Abnormalities, Multiple↗
PubMed2001

Serum levels and differential expression of CD44 in childhood leukemia and malignant lymphoma: correlation with prognostic criteria and survival.

BACKGROUND: The CD44, a cell surface proteoglycan, participates in a variety of function including tumor dissemination and metastasis. However, there are no available data on the prognostic significance of CD44 expression of tumor tissue correlated with serum sCD44 level in childhood leukemias and lymphomas. METHODS: Serum levels and leukemic cell tumor tissue expression of CD44 were detected in 54 children with acute leukemia and malignant lymphoma. Serum samples were obtained from all patients before treatment and during remission. Twelve age-matched healthy children were included as a control group. RESULTS: The serum CD44 levels were significantly higher in patients with Hodgkin's disease (HD), non-Hodgkin's lymphoma (NHL), Burkitt's lymphoma (BL) and acute lymphoblastic leukemia (ALL) than those in the control group. The median values were 1627.0, 1336.0, 1318.5, 1730.4, 902.7 ng/mL, respectively, and P<0.001, P<0.01, P<0.01, P<0.05 in comparisons, respectively. However, there was no significant difference between acute myeloid leukemia (AML) and the control group (median values: 900.3 and 902.7 ng/mL, respectively, P>0.05). Serum sCD44 levels significantly declined in HD, NHL and ALL patients who were in complete remission (median values: 684.0, 573.8 and 1101.1 ng/mL, respectively, P<0.05 in each comparison). Patients with HD had higher levels of serum sCD44 and correlated well with higher erythrocyte sedimentation rate (ESR), B-symptoms and advanced-stage disease (P<0.05, P<0.05 and P<0.01, respectively). Expression of CD44 was significantly high in patients with HD and NHL who were in advanced stages of disease. High serum CD44 level was also associated with high tumor tissue expression of CD44 in patients with HD and BL. In addition, patients with higher levels of serum sCD44, had a poorer outcome and survival than those with lower sCD44 levels in HD and NHL groups. CONCLUSIONS: A high serum sCD44 level and/or tumor tissue expression at diagnosis is associated with poor prognostic criteria and/or unfavorable outcome in childhood leukemias and lymphomas.

Adolescent↗
PubMed2000

Natural killer cell numbers and cytotoxic activity in pediatric Hodgkin disease.

In this study peripheral blood natural killer (NK) cell activity was evaluated in 17 pediatric cases with Hodgkin disease (HD) (9 untreated, 8 in remission) and 20 age-matched healthy children. Peripheral blood CD16 and CD56 molecule expressions were also examined. No difference related to NK cell numbers and cytotoxic activity was detected at either stage of the disease. In cases in which long-term remission has been achieved (> or = 5 years) NK cell activity was slightly but not significantly increased in parallel with remission duration. Finally, no relation between NK cell activity and the etiology, prognosis, and severity of the disease has been established in children with HD.

Adolescent↗
PubMed2000

Immune thrombocytopenia and hemolytic anemia as a presenting manifestation of Hodgkin disease.

A very unusual clinical presentation of Hodgkin disease with immune thrombocytopenia and autoimmune hemolytic anemia is reported. A 6.5-year-old boy presented with thrombocytopenia, Coombs' positive hemolytic anemia, and multiple small posterior cervical lymph nodes. After a course of high-dose methylprednisolone therapy with a diagnosis of Evans syndrome, complete response for thrombocytopenia and partial response for anemia was achieved. Six weeks later there was a sudden increase in the size of left posterior cervical lymph nodes and a biopsy was compatible with Hodgkin disease, mixed cellularity type. The child was successfully treated with chemotherapy and radiation therapy. He has been off therapy for 28 months and has no clinical or laboratory evidence of autoimmune cytopenia. A combination of immune thrombocytopenia and autoimmune hemolytic anemia may be associated with Hodgkin disease. The recognition of this clinical picture as a complication of Hodgkin disease has important implications. This complication appeares to be managed best by the definitive treatment of Hodgkin disease.

Anemia, Hemolytic, Autoimmune↗
PubMed2000

Anaesthesia for Friedreich's ataxia. Case report.

Friedreich's ataxia is an inherited neuromuscular disorder often associated with significant cardiac disease and requiring special care during anaesthesia because of increased sensitivity to muscle relaxants. We report a 37 years old female patient with Friedreich's ataxia who underwent anaesthesia for total hip replacement because of degenerative hip arthritis. Anaesthesia was induced with alfentanil and propofol. Endotracheal intubation was achieved without the use of any muscle relaxants and muscle relaxants were avoided throughout the operation. Anaesthesia was maintained with propofol infusion and intermittent bolus doses of alfentanil. At the end of the procedure recovery from anaesthesia was fast and uneventful. When there is no absolute indication for neuromuscular blocking agents as its the case for many orthopaedic operations, avoiding these drugs would simply avoid many potential complications due to muscle relaxant use in this group of patients.

Adult↗
PubMed1999

Fungal colonization and infection in children with acute leukemia and lymphoma during induction therapy.

BACKGROUND: Fungal infection represents a growing problem in children with hematologic malignancies. During chemotherapy induced neutropenia, colonization with fungi is considered a major risk factor for subsequent fungal infection. The rates and risk factors for mycotic infections in pediatric oncology patients is undetermined, particularly for centers in developing countries. The aim of this study was to evaluate the rates and risk factors of fungal colonization in children with acute leukemia and lymphoma at one of the major pediatric hematology/oncology centers in Turkey. PROCEDURE: Fifty-two consecutive children newly diagnosed with acute leukemia and lymphoma during intensive remission induction therapy were evaluated for the occurrence of fungal colonization (defined as at least one positive surveillance culture) and infection. RESULTS: Thirty-six of the 52 patients (69.2%) were colonized by Candida albicans which was the only fungus isolated from surveillance cultures. There were three (5.8%) proven systemic fungal infections: two cases of candidemia and one case of brain abscess with Aspergillus spp. isolated from tissue. All patients with fungal colonization were receiving prophylactic or curative antibiotics. No significant association was found between type of disease and fungal colonization, but there was a significant association with neutropenia. CONCLUSIONS: Our findings suggest that there is a high rate of fungal colonization in children receiving remission induction therapy for acute leukemia and lymphoma. Limiting the use of antibiotics and instituting antifungal chemoprophylaxis may decrease the rate, while the early initiation of empiric antifungal therapy in patients with fever and suspected mycotic colonization may increase survival in these patients.

Adolescent↗
PubMed1995

Late effects of chemoradiotherapy in pediatric Hodgkin's disease.

We treated 137 Turkish children with biopsy-proven Hodgkin's disease, followed up between the years 1964 and 1989. Most patients were treated and were in advanced stage with histological subtype of mixed cellularity (67.5%). Radiotherapy (Mantle form) and/or MOPP, ABVD and OPPA combination chemotherapy regimens were used in 75.84% of patients. The follow-up period in these patients ranged from 5 to 24 years. The late effects in 28 patients who were evaluated for the late sequelae of chemoradiotherapy are presented. Seven out of 28 patients showed retarded sexual maturation. Testicular and ovarian functions were assessed in 11 patients, all of whom showed elevated serum FSH levels and 2 azoospermia. Analysis of thyroid functions was carried out in patients receiving radiotherapy to the neck. The thyroid gland was palpable in 6 patients. Further analysis showed diffuse hyperplasia in 5 and nodular in 1 patient. The nodule was excised and reported as "nodular colloidal goiter". Two patients had elevated TSH levels. "Swan-like neck" was observed in 3 patients who had received 40 to 42 Gy radiotherapy to the neck. Cirrhosis due to chronic hepatitis B infection was diagnosed in 2 patients as an unusual late complication. The secondary malignancy occurred in only 1 case in the form of "fibrosarcoma". The second neoplasm was probably radiation-induced as it occurred in the field of prior radiotherapy.

Adolescent↗
PubMed1995

Granulocyte-macrophage colony stimulating factor (rh-GM-CSF) in the treatment of chemotherapy-induced neutropenia.

Neutropenic pediatric patients with solid tumors and malignant lymphomas were treated with recombinant granulocyte-macrophage colony stimulating factor (rh-GM-CSF). Eleven patients, including seven lympho-reticular malignancies, two Ewing's sarcoma and one patient in each group with the diagnosis of nasopharyngeal rhabdomyosarcoma, malignant mesenchymal tumor, entered the study. Six were females and five were males, the mean age was 10.4 yr, the range was 4 to 21 years. rh-GM-CSF was given at the dose of 5 micrograms/kg s.c. daily, starting either on the day following the last day of cytotoxic chemotherapy or when ANC < 1000/ml was determined. All patients received rh-GM-CSF for a total of seven days. Hematopoietic recovery occurred in all children except one. The response to rh-GM-CSF was achieved in a mean time of 7.4 days. Tolerance to rh-GM-CSF treatment was good. Adverse events were documented as fever, nausea, vomiting, fatigue, chills and itching. Sagittal sinus thrombosis developed in one patient 5 days following the completion of chemotherapy and rh-GM-CSF cycle. In conclusion, rh-GM-CSF can be applied during the intensive chemotherapy schedules of pediatric cancer patients.

Adolescent↗
PubMed1994

Burkitt's lymphoma in Turkish children: clinical, viral [EBV] and molecular studies.

Eighty-one Turkish children with Burkitt's lymphoma (BL) were observed during a period of 24 years (1968-1992). The diagnosis was established histologically according to WHO criteria. BL represented 48.5% of NHL in this series. The median age of patients was 5 years with a sex (M/F) ratio of 2.3/1. The most common primary site of tumor involvement at initial presentation was the abdomen (70.4%), which was followed by facial tumors, in particular the jaw and orbit (45.7%). The majority of the patients (84.0%) were in advanced stages (C and D) at initial diagnosis. Facial tumors observed in Turkish children with BL were more similar to African Burkitt's lymphoma than American or European cases. High titers of antibodies against VCA and EA of EBV were also observed in 32 recent cases of BL. Preliminary molecular and immunologic studies revealed EBV-DNA (type I) and T cell deficiency. The clinical presentation, median age, and association with EBV revealed that BL appears to be inbetween African and non-African types in Turkish children. This will be further elucidated in the future by direct examination of tumor cells for EBV and investigation of the molecular characteristics in these cases.

Adolescent↗
PubMed1993

Burkitt's lymphoma between African and American types in Turkish children: clinical, viral (EBV), and molecular studies.

Seventy-two Turkish children with Burkitt's lymphoma (BL) observed during a period of 22 years (1968-1990) have been analysed retrospectively. The diagnosis was established histologically according to WHO criteria. BL represented 50% of NHL in this series. The patients were staged according to Ziegler's system. The median age of patients was 5.5 years with a sex (M/F) ratio of 2.1/1. The most common primary site of tumor involvement was the abdomen (69.4%), which was followed by facial tumors, in particular the jaw and orbit (49.9%). There were 21 cases with jaw (29.1%) and 15 cases with orbital involvement (20.8%) at initial presentation. The majority of the patients (84.4%) were in advanced stages (C and D) at initial diagnosis. Facial tumors observed in Turkish children with BL were more similar to African Burkitt's lymphoma than American or European cases. High titers of antibodies against VCA and EA of EBV were also seen in our recent cases of BL. Two main treatment regimens, namely, single agent chemotherapy with cyclophosphamide (CYX) (1968-1974) and three drug (COM) combination chemotherapy, were used consecutively (1974-1988). COM has been shown to produce better results than single agent therapy. The clinical presentation, mean age, and high antibodies (IgG) to EBV and preliminary molecular studies revealed that BL appears to be in between African and non-African types in Turkish children. This will be further elucidated by direct examination of tumor cells for EBV and investigation of the molecular characteristics of Turkish tumors. Such studies are presently under way.

Adolescent↗
PubMed1993

T-lymphocyte sub-populations in orbito-ocular granulocytic sarcoma (OOGS) and acute myelocytic leukemia (AML): a preliminary study.

The aetiology of GS remains obscure and a little is known about the immune competence of these patients. Interestingly, all children with OOGS were from low 'socio-economic status' and showed diminished delayed hypersensitivity reactions and reduced T cell counts (E-R) in our previous observation. We present herewith a preliminary data on evaluation of T cell sub-populations determined by monoclonal antibodies (CD3, CD4, CD8 and CD16 cells) in 10 patients with OOGS and AML prior to treatment. Quantitative immunoglobulin determinations of IgA, IgM, IgG were also made. The percentage of Pan T (CD3), CD4, CD8 cells were significantly lower than those in the controls (p < 0.01). The immunoglobulin levels were slightly elevated suggesting normal B cell functions. In conclusion, these preliminary findings suggest that cellular immune deficiency may be an underlying cause.

CD3 Complex↗
PubMed1993

Orbito-ocular granulocytic sarcoma (OOGS) and acute myeloblastic leukemia (AML) with duplication of Philadelphia chromosome.

A 6-year-old Turkish boy with bilateral orbito-ocular granulocytic sarcoma and AML is described. Cytogenetic studies on peripheral blood disclosed an abnormal hyperdiploid population with a double Ph chromosome. Despite intensive chemotherapy, he achieved only partial remission. Repeated cytogenetic studies on bone marrow during relapse revealed the persistence of double Ph chromosome. The aggressive course and the short survival time of this patient, despite adequate chemo-radiotherapy, may be explained by the presence of the double Ph chromosome.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

[Comparison of carrageenan-induced experimental inflammation in cheek and on dorsum of guinea-pigs].

Carrageenan is a high molecular weight sulfated polygalactose extracted from the marine algae and several biological and immunological properties. Carrageenan granuloma induced subcutaneously in guinea pigs has been widely used in connective tissue studies. Carrageenan is also commonly used as an excellent phylogistic agent for inducing experimental edema. In the present investigation carrageenan granuloma produced on the dorsum of guinea was compared with the inflammatory reaction produced in the cheek. The histopathologic investigations showed that the inflammatory reaction occurred in the buccal tissues was more powerful and the healing manifestations appeared earlier and continued more rapidly in the cheek.

Animals↗