What has GWAS done for HLA and disease associations?

The major histocompatibility complex (MHC) is located in chromosome 6p21 and contains crucial regulators of immune response, including human leucocyte antigen (HLA) genes, alongside other genes with nonimmunological roles. More recently, a repertoire of noncoding RNA genes, including expressed pseudogenes, has also been identified. The MHC is the most gene dense and most polymorphic part of the human genome. The region exhibits haplotype-specific linkage disequilibrium patterns, contains the strongest cis- and trans-eQTLs/meQTLs in the genome and is known as a hot spot for disease associations. Another layer of complexity is provided to the region by the extreme structural variation and copy number variations. While the HLA-B gene has the highest number of alleles, the HLA-DR/DQ subregion is structurally most variable and shows the highest number of disease associations. Reliance on a single reference sequence has complicated the design, execution and analysis of GWAS for the MHC region and not infrequently, the MHC region has even been excluded from the analysis of GWAS data. Here, we contrast features of the MHC region with the rest of the genome and highlight its complexities, including its functional polymorphisms beyond those determined by single nucleotide polymorphisms or single amino acid residues. One of the several issues with customary GWAS analysis is that it does not address this additional layer of polymorphisms unique to the MHC region. We highlight alternative approaches that may assist with the analysis of GWAS data from the MHC region and unravel associations with all functional polymorphisms beyond single SNPs. We suggest that despite already showing the highest number of disease associations, the true extent of the involvement of the MHC region in disease genetics may not have been uncovered.

The frequency of C609T polymorphism in the NQO1 gene and its relation to cytogenetic abnormalities in patients with myelodysplastic syndrome

The aim of the present study is to evaluate the frequency of C609T polymorphism in the NQO1 (NAD(P)H) quinon oxydoreductase) gene and its relation to cytogenetic abnormalities in patients with Myelodysplastic Syndrome (MDS). The study group consisted of 80 patients MDS with 13 of them in the pediatric age group. The frequency of the NQO1 gene polymorphism was compared with a healthy control group involving 423 individuals. Cytogenetic abnormalities were detected in 43 patients (54%). In patients with MDS the overall frequency of the C609T polymorphism was not different than controls. Also, although the frequency of the C609T polymorphism was higher in patients with secondary MDS (sMDS) (OR: 1.893, 95% CI: 0.840-4.265, p=0.238) , 5/del(5q) (OR:1.298, 95% CI: 0.331-5.086,p=0.124), +21(OR:1.817, 95% CI:0.429-7698,p=0.124) and t(8;21) (OR:3.028, 95% CI: 0.604-15.172,p=0.137) groups, the difference did not reach statistical significiance. Our results do not support the view that the C609T polymorphism has a role in the pathogenesis of MDS. Also the frequency of the C609T allele did not seem to be associated with cytogenetic abnormalities.

Evaluating CT Perfusion Deficits in Global Cerebral Edema after Aneurysmal Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Global cerebral edema is an independent predictor of mortality and poor outcomes after aneurysmal SAH. Global cerebral edema, a complex disease process, is thought to be associated with an altered cerebral autoregulatory response. We studied the association between cerebral hemodynamics and early global cerebral edema by using CTP.

MATERIALS AND METHODS

We retrospectively studied consecutive patients with aneurysmal SAH with admission CTP performed at days 0-3. Two neuroradiologists classified global cerebral edema and hydrocephalus on NCCT performed concurrently with CTP. Global cerebral edema was defined as diffuse effacement of the sulci and/or basal cisterns or diffuse disruption of the cerebral gray-white matter junction. CTP was postprocessed into CBF and MTT maps by using a standardized method. Quantitative analysis of CTP was performed by using standard protocol with ROI sampling of the cerebral cortex. The Fisher exact test, Mann-Whitney test, and independent-samples t test were used to determine statistical associations.

RESULTS

Of the 45 patients included, 42% (19/45) had global cerebral edema and 58% (26/45) did not. Patient groups with and without global cerebral edema were well-matched for demographic and clinical data. Patients with global cerebral edema were more likely to have qualitative global CTP deficits than those without global cerebral edema (P = .001) with an OR = 13.3 (95% CI, 2.09-138.63). Patients with global cerebral edema also had a very strong trend toward statistical significance, with reduced quantitative CBF compared with patients without global cerebral edema (P = .064).

CONCLUSIONS

Global perfusion deficits are significantly associated with global cerebral edema in the early phase after aneurysmal SAH, supporting the theory that hemodynamic disturbances occur in global cerebral edema.

A certified plasmid reference material for the standardisation of BCR-ABL1 mRNA quantification by real-time quantitative PCR

Serial quantification of BCR–ABL1 mRNA is an important therapeutic indicator in chronic myeloid leukaemia, but there is a substantial variation in results reported by different laboratories. To improve comparability, an internationally accepted plasmid certified reference material (CRM) was developed according to ISO Guide 34:2009. Fragments of BCR–ABL1 (e14a2 mRNA fusion), BCR and GUSB transcripts were amplified and cloned into pUC18 to yield plasmid pIRMM0099. Six different linearised plasmid solutions were produced with the following copy number concentrations, assigned by digital PCR, and expanded uncertainties: 1.08±0.13 × 10⁶, 1.08±0.11 × 10⁵, 1.03±0.10 × 10⁴, 1.02±0.09 × 10³, 1.04±0.10 × 10² and 10.0±1.5 copies/μl. The certification of the material for the number of specific DNA fragments per plasmid, copy number concentration of the plasmid solutions and the assessment of inter-unit heterogeneity and stability were performed according to ISO Guide 35:2006. Two suitability studies performed by 63 BCR–ABL1 testing laboratories demonstrated that this set of 6 plasmid CRMs can help to standardise a number of measured transcripts of e14a2 BCR–ABL1 and three control genes (ABL1, BCR and GUSB). The set of six plasmid CRMs is distributed worldwide by the Institute for Reference Materials and Measurements (Belgium) and its authorised distributors (https://ec.europa.eu/jrc/en/reference-materials/catalogue/; CRM code ERM-AD623a-f).

Deregulated WNT signaling in childhood T-cell acute lymphoblastic leukemia

WNT signaling has been implicated in the regulation of hematopoietic stem cells and plays an important role during T-cell development in thymus. Here we investigated WNT pathway activation in childhood T-cell acute lymphoblastic leukemia (T-ALL) patients. To evaluate the potential role of WNT signaling in T-cell leukomogenesis, we performed expression analysis of key components of WNT pathway. More than 85% of the childhood T-ALL patients showed upregulated β-catenin expression at the protein level compared with normal human thymocytes. The impact of this upregulation was reflected in high expression of known target genes (AXIN2, c-MYC, TCF1 and LEF). Especially AXIN2, the universal target gene of WNT pathway, was upregulated at both mRNA and protein levels in ∼40% of the patients. When β-CATENIN gene was silenced by small interfering RNA, the cancer cells showed higher rates of apoptosis. These results demonstrate that abnormal WNT signaling activation occurs in a significant fraction of human T-ALL cases independent of known T-ALL risk factors. We conclude that deregulated WNT signaling is a novel oncogenic event in childhood T-ALL.

Expression analysis and clinical correlation of aquaporin 1 and 4 genes in human hippocampal sclerosis

Mesial temporal sclerosis (MTS) is the most frequent cause of drug resistant symptomatic partial epilepsy. The mechanism and genetic background of this unique pathology are not well understood. Aquaporins (AQP) are regulators of water homeostasis in the brain and are expressed in the human hippocampus. We explored the role of AQP genes in the pathogenetic mechanisms of MTS through an evaluation of gene expression in surgically removed human brain tissue. We analyzed AQP1 and 4 mRNA levels by quantitative real-time polymerase chain reaction and normalized to ABL and cyclophilin genes, followed by immunohistochemistry for AQP4. Relative expressions were calculated according to the delta Ct method and the results were compared using the Mann-Whitney U test. Brain specimens of 23 patients with epilepsy who had undergone surgery for MTS and seven control autopsy specimens were investigated. Clinical findings were concordant with previous studies and 61% of the patients were seizure-free in the postoperative period. AQP1 and 4 gene expression levels did not differ between MTS patients and control groups. Immunofluorescence analysis of AQP4 supported the expression results, showing no difference. Previous studies have reported contradictory results about the expression levels of AQP in MTS. To our knowledge, only one study has suggested upregulation whereas the other indicated downregulation of perivascular AQP4. Our study did not support these findings and may rule out the involvement of AQP in human MTS.

Glutathione S-transferase P1 polymorphisms are associated with time to tumor progression in small cell lung cancer patients

PURPOSE

Many of commonly used chemotherapeutics in lung cancer treatment are metabolized by glutathione-S transferases (GSTs). The placental isoform of GST (GSTP1) is the most abundant isoform in the lung. Polymorphisms within the GSTP1 may result in alterations in enzyme activity and change sensitivity to platinum-based chemotherapy. We investigated whether the polymorphism within the exons 5 and 6 of GSTP1 gene may change response to therapy, time to tumor progression (TTP) and overall survival in small cell lung cancer (SCLC) patients.

METHODS

Ninety-four histologically confirmed patients with SCLC were enrolled in this study during 1995-2006. GSTP1 Ile105Val polymorphism in exon 5 and GSTP1 Ala- 114Val polymorphism in exon 6 were determined by using PCR-RFLP techniques. Associations between the GSTP1 polymorphisms and treatment response were evaluated using the chi-square test. Associations between the GSTP1 polymorphisms and TTP and overall survival were compared using Kaplan-Meier survival curves.

RESULTS

We found no significant associations between exon 5 and exon 6 GSTP1 gene polymorphisms and response to therapy or overall survival. Patients carrying both variant exon 5 (Ile/Val or Val/Val) and variant exon 6 (Ala/Val) genotypes had significantly shorter TTP (5 vs. 8 months, p = 0.04). Moreover, patients with heterozygote exon 6 variant had presented with extensive-stage disease.

CONCLUSION

No individual effect of variant alleles was found in relation to chemotherapy response, median TTP and overall survival. The carriage of both types of variant alleles may predict worse outcome.

Effects of Imatinib Mesylate on Renin–Angiotensin System (RAS) Activity during the Clinical Course of Chronic Myeloid Leukaemia

The renin–angiotensin system (RAS) is involved in cell growth, proliferation and differentiation in bone marrow in an autocrine–paracrine manner, and it modulates normal and neoplastic haematopoietic cell proliferation. This study aimed to assess expressions of the RAS components, renin, angiotensinogen and angiotensin-converting enzyme (ACE), during imatinib mesylate treatment of patients with chronic myeloid leukaemia (CML). Expressions of RAS components were studied in patients with CML at the time of diagnosis ( n = 83) and at 3, 6 and 12 months after diagnosis ( n = 35) by quantitative real-time polymerase chain reaction. De novo CML patients had increased ACE, angiotensinogen and renin mRNA levels and these expression levels decreased following administration of imatinib. The RAS activities were significantly different among Sokal risk groups of CML, highlighting the altered biological activity of RAS in neoplastic disorders. The results of this study confirm that haematopoietic RAS affects neoplastic cell production, which may be altered via administration of tyrosine kinase inhibitors such as imatinib mesylate.

Validation of breast cancer nomograms for predicting the non-sentinel lymph node metastases after a positive sentinel lymph node biopsy in a multi-center study

OBJECTIVE

In the study, our aim was to evaluate the predictability of four different nomograms on non-sentinel lymph node metastases (NSLNM) in breast cancer (BC) patients with positive sentinel lymph node (SLN) biopsy in a multi-center study.

METHODS

We identified 607 patients who had a positive SLN biopsy and completion axillary lymph node dissection (CALND) at seven different BC treatment centers in Turkey. The BC nomograms developed by the Memorial Sloan Kettering Cancer Center (MSKCC), Tenon Hospital, Cambridge University, and Stanford University were used to calculate the probability of NSLNM. Area under (AUC) Receiver Operating Characteristics Curve (ROC) was calculated for each nomogram and values greater than 0.70 were accepted as demonstrating good discrimination.

RESULTS

Two hundred and eighty-seven patients (287) of 607 patients (47.2%) had a positive axillary NSLNM. The AUC values were 0.705, 0.711, 0.730, and 0.582 for the MSKCC, Cambridge, Stanford, and Tenon models, respectively. On the multivariate analysis; overall metastasis size (OMS), lymphovascular invasion (LVI), and proportion of positive SLN to total SLN were found statistically significant. We created a formula to predict the NSLNM in our patient population and the AUC value of this formula was 0.8023.

CONCLUSIONS

The MSKCC, Cambridge, and Stanford nomograms were good discriminators of NSLNM in SLN positive BC patients in this study. A newly created formula in this study needs to be validated in prospective studies in different patient populations. A nomogram to predict NSLNM in patients with positive SLN biopsy developed at one institution should be used with caution.

Seroreactivity against PTEN-induced putative kinase 1 (PINK1) in Turkish patients with Behçet's disease

BACKGROUND

Behçet's disease (BD) is a multisystem inflammatory disorder characterized by recurrent oral ulcers, genital ulcers and ocular inflammation, as well as skin, joint, vascular, pulmonary, central nervous system (CNS) and gastrointestinal tract manifestations. The etiopathogenesis of BD has not yet been identified; but it has generally been accepted that several environmental factors may induce an inflammatory attack in genetically susceptible individuals. In this study, we aimed to identify antigens that could elicit high-titer IgG responses by the serological analysis of recombinant expression of cDNA libraries method (SEREX).

METHODS

We screened a human testis cDNA library with pooled sera obtained from 4 BD patients by SEREX. Antigens that were identified with the initial analysis were selected for seroreactivity analysis of a larger group of BD patients (n=78) and controls (n=66) by serological immunoscreening.

RESULTS

We observed seroreactivity against 6 antigens using the pooled sera. These included rabaptin 5 (RABPT5), PTEN-induced putative kinase 1 (PINK1), switch associated protein 70 (SWAP70), interferon-induced protein with tetratricopeptide repeats 2 (IFIT2), ankyrin repeat domain 20 family, member A1 (ANKRD20A1), and an unknown antigen. Eleven out of 82 (13.4%) BD patients were found to have antibodies elicited against PINK1 antigen, when none of the control sera showed reactivity (p=0.001). There was no significant difference in the frequency of other defined antigens between the patient and control groups. However, among BD clinical sub-groups, anti-SWAP70 antibodies were found to associate with vascular involvement.

DISCUSSION

In this study, antibodies against PINK1 were found to specifically associate with BD while SWAP70 antibody was associated with clinical sub-groups of BD. Although variations in both genetic background and environmental factors may affect the outcome of serological responses, our results suggest that serological screening can be used to identify antigens that elicit antibody responses associated with BD.

Prognostic and predictive value of vascular endothelial growth factor and soluble flt-1 and kdr levels in the sera of small cell lung cancer patients

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Background: Small cell lung cancer (SCLC) has a rapid growth rate, and is characterized by early metastases. Tumor growth is dependent on angiogenesis. Vascular endothelial growth factor (VEGF) is an important regulator of angiogenesis. Whether surveillance of pre and post treatment serum VEGF and its receptors Flt-1 and Kdr levels in SCLC patients have impact on clinical outcome is unknown. Methods: From February 2001- January 2003, 39 consecutive patients (34 male, 5 female) with histologically proven SCLC were enrolled into the study. The patients were staged as limited and extensive according to the Veterans Administration Lung Group (VALSG). Pre treatment (n:39) and post treatment (n:25) serum samples of the same patients after 3 months of treatment were collected. The levels of VEGF and its receptors Flt-1 and kdr are measured in the serum by quantitative sandwich enzyme immunoassay technique. Statistical analysis was performed using the SPSS 10.0 pocket program. Results: The median pretreatment serum VEGF, Flt-1, and Kdr levels were 1,200 pg/ml (range, 1,414.3±956.2 pg/ml), 85 pg/ml (range, 97.8±70.7 pg/ml), and 11,550 pg/ml (range, 14,481±6,267 pg/ml) respectively. The pretreatment serum VEGF, Flt-1, and Kdr concentrations were not different in limited and extensive stages. We detected a poor but positive correlation between VEGF and Kdr (r=0.46, p=0.003). Pretreatment low serum VEGF value (<728.5 pg/ml) and good response to treatment were found as good prognostic factors in multivariate analysis. Surveillance of serum VEGF and Flt-1, Kdr values did not correlate with clinical parameters. Conclusions: Serum VEGF was found to be a significant and independent prognostic factor in SCLC patients. We showed a limited association between serum levels of VEGF and Kdr. Whether the levels of serum VEGF and its receptors Flt-1 and kdr have value in detecting treatment modalities of SCLC needs further studies.

No significant financial relationships to disclose.

SOX2 antibody responses in patients with various tumor types and SCLC with and without paraneoplastic neurologic syndromes

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Background: SOX2, a member of the SOX Group B family of transcription factors, is expressed in normal adult brain, testis and prostate as well as in many SCLC cell lines. Spontaneous antibody responses to SOX2 have previously been shown to be detectable in SCLC patients. We undertook a retrospective study to determine whether antibody responses were detectable in patients with other malignancies and in patients with paraneoplastic neurologic syndromes (PND/PNS). Methods: Previously obtained serum samples from patients with no known disease (n = 84), breast and ovarian cancer (n = 35 each), melanoma (n = 42), NSCLC (n = 150), and SCLC patients, 90 from Turkey and 68 patients studied for PND, were tested by ELISA using serial 4-fold dilutions for anti-SOX2 and anti-HuD antibody. Results: Preliminary data shows SOX2 reactivity in 5/84 (6%) normal volunteer sera, 8/35 (23%) in both breast and ovarian cancer patients, 4/42 (9%) melanoma patients, 20/150 (13.3%) NSCLC patients, and 56/158 (35.4%) SCLC patients. Compared to controls, there was a statistically significant difference in SOX2 immunoreactivity in breast, ovarian (p = 0.007 for both) and SCLC patients (p < 0.001), and a trend was noted in NSCLC patients (p = 0.080). No breast, ovarian, melanoma or normal patient had SOX2 antibody titers ≥1:6400, compared with 32/56 (57.1%) of SCLC (p < 0.01) and 6/20 (30%) NSCLC patients (p < 0.16). Nine SCLC patients had neurologic symptoms and were previously found to have anti-HuD antibodies, associated with a diagnosis of PND. This was confirmed in 8/9 patients in our assay. However, none of the nine patients displayed anti-SOX2 reactivity. Eleven additional SCLC patients were found to be HuD positive by our ELISA. Conclusions: Anti-SOX2 responses are found in a significant proportion of patients with SCLC, breast and ovarian cancer, but not in melanoma patients compared to normal controls. Patients with SCLC have higher titer antibodies when compared with the other groups, and anti-SOX2 antibodies do not appear to associate with anti-HuD responses, supporting the hypothesis that SOX2 immune responses are not associated with PND and may be useful as a vaccine target. Supported by the Cancer and Leukemia Group B/Aventis Oncology Award and the Steps for Breath Foundation.

No significant financial relationships to disclose.

Which anesthetic agent alters the hemodynamic status during pediatric catheterization? comparison of propofol versus ketamine

OBJECTIVE

To compare the effects of propofol and ketamine on systemic and pulmonary circulations in pediatric patients scheduled for elective cardiac catheterization.

DESIGN

Prospective, randomized, and blinded.

SETTING

University hospital.

PARTICIPANTS

Children (n = 41) undergoing cardiac catheterization.

INTERVENTIONS

All children were premedicated with oral midazolam 60 minutes before the procedure. Patients were separated into 3 groups according to shunts diagnosed by transthoracic echocardiography before the catheterization procedure: patients without cardiac shunt (Group I, n = 11), left-to-right shunt (Group II, n = 12), and right-to-left shunt (Group III, n = 18). A continuous infusion of propofol (100-200 microg/kg/min) or ketamine (50-75 microg/kg/min) was randomly started in all groups to obtain immobility during the procedure. Hemodynamic data, including systemic venous, pulmonary artery and vein, aortic saturations and pressures, were recorded; Qp/Qs were calculated. The same set of data was recorded before discontinuation of infusions at the end of the procedure.

MEASUREMENTS AND MAIN RESULTS

After the propofol administration, in all 3 patient groups propofol infusion was associated with significant decreases in systemic mean arterial pressure. In groups with cardiac shunts (Group II and III), propofol infusion significantly decreased systemic vascular resistance and increased systemic blood flow, whereas pulmonary vascular resistance and pulmonary blood flow did not change significantly. These changes resulted in decreased left-to-right shunting and increased right-to-left shunting; the pulmonary-to-systemic flow ratio decreased significantly. On the other hand, after ketamine infusion, systemic mean arterial pressure increased significantly in all patient groups, but pulmonary mean arterial pressure, systemic vascular resistance, and pulmonary vascular resistance were unchanged.

CONCLUSION

In children with cardiac shunting, the principal hemodynamic effect of propofol is a decrease in systemic vascular resistance. In children with intracardiac shunting, this results in an increase in right-to-left shunting and a decrease in the ratio of pulmonary to systemic blood flow, which may lead to arterial desaturation. Ketamine did not produce these changes. The authors suggested that during cardiac catheterization in children, both the anesthesiologists and cardiologists need to know that anesthetic agents can significantly alter the hemodynamic status in children with complex congenital heart defects and affect the results of hemodynamic calculations that are important for decision-making and treatment of these patients.

Concurrent methylation of multiple genes in childhood ALL: Correlation with phenotype and molecular subgroup

Multiple genes have been shown to be independently hypermethylated in lymphoid malignancies. We report here on the extent of concurrent methylation of E-cadherin, Dap-kinase, O(6)MGMT, p73, p16, p15 and p14 in 129 pediatric ALL cases. While most of these genes demonstrated methylation in a proportion of cases, O(6)MGMT, p16 and p14 were infrequently methylated (11, 7 and 3%, respectively). Methylation of at least one gene was found in the vast majority (83%) of cases. To determine the extent and concordance of methylation we calculated a methylation index (MI=number of methylated genes/number of studied genes) for each sample. The average MI was 0.28, corresponding to 2/7 methylated genes. MI was correlated with standard prognostic factors, including immunophenotype, age, sex, WBC and presence of specific translocations (TEL-AML1, BCR-ABL, E2A-PBX1 or MLL-AF4). We determined that children >/=10 years old and children presenting with high WBC (>/=50 x 10(9)/l) both associated with a higher MI (P<0.01 and <0.05, respectively). T-ALLs demonstrated a lower MI (median=0.17) than precursor B ALLs (median=0.28). Among the different molecular subgroups, MLL-ALLs had the highest MI (mean=0.35), while ALLs carrying the t(1;19) had the lowest MI (mean=0.07). The most common epigenetic lesion in childhood ALL was methylation of E-cadherin (72%) independent of the molecular subtype or other clinicopathological factors.

Tumour necrosis factor-alpha gene promoter region -308 and -376 G-->A polymorphisms in Behçet's disease

OBJECTIVE

Contribution of HLA-B51 to the genetic susceptibility for Behçet's disease is well documented and recent studies suggest involvement of other genes. Tumour necrosis factor (TNF) genes are located in the vicinity of the HLA-B locus. Polymorphisms in the promoter region of TNF-alpha gene has been found to be associated with altered TNF secretion, and it may have a prominent role in the increased inflammatory responses of Behçet's disease.

METHODS

The study group consisted of 99 Behçet's disease patients and 96 healthy matched controls. All patients fulfilled the International Study Group criteria for Behçet's disease. The TNF-alpha -308 and -376 promoter alleles were assigned by the digestion of each amplified PCR product with NcoI and TasI enzymes, respectively.

RESULTS

No significant difference was observed in the distribution of TNF-alpha promoter region polymorphisms between patients with Behçet's disease and controls. There was no association between the presence of uncommon -308A and -376A alleles and the manifestations or severity of Behçet's disease either. The TNF-alpha -308A allele and HLA-B*50 was found to be associated in this series of Turkish patients and controls.

CONCLUSION

The role of TNF-alpha promoter region -308 and -376 polymorphisms in the pathogenesis of Behçet's disease is not supported by this data. The overexpression of TNF-alpha in Behçet's disease may be caused by other polymorphisms in the TNF gene or by post-transcriptional mechanisms.

Genetic polymorphism of cytochrome P450 2E1 in the Turkish population

CYP 2E1 is involved in metabolic activation of carcinogenic N-nitrosamines, benzene, urethane and other low molecular weight compounds. CYP2E1 gene is present in the population in various polymorphic forms. We detected the RFLP of the human CYP2E1 gene with the restriction endonuclease PstI, RsaI and DraI in a group of 153 Turkish individuals. According to the results of the PstI/RsaI analysis, 96.07% of the subjects were of the c1/c1 genotype, and 3.93% were of the c1/c2 genotype. In the DraI RFLP analysis, 84.30% DD genotype, 15.03% CD genotype and 0.66% CC genotype were determined. The data obtained may be useful in epidemiological studies of the influence of CYP2E1 polymorphism on carcinogenesis.

Is AML1/ETO gene expression a good prognostic factor in pediatric acute myeloblastic leukemia?

To assess the clinical significance of AML1/ETO gene detected by nested reverse transcriptase polymerase chain reaction, the outcome of 7 patients with acute myeloblastic leukemia between 3 and 14 years of age were presented. All patients had complete remission (CR) at the end of induction (AML-MRC 10 protocol) and 4 underwent unpurged autologous, 2 allogeneic (from matched siblings) non-T-cell-depleted bone marrow transplantations (BMT) in first CR. One patient died due to allogeneic BMT-related complications, and 4 patients relapsed at 13, 17, 18, and 26 months. Only one patient achieved second CR. All relapsed patients died between 18 and 36 months with resistant disease (n = 3) or infection during salvage chemotherapy (n = 1). Two patients who had autologous BMT are alive and disease free at 44 and 50 months. Although statistical significance could not be shown, event-free survival and overall survival rates of AML1/ETO-positive patients (28.57 and 28.57%, respectively) at 3.5 years were even lower than those of AML1/ETO-negative patients. The results confirm some previous reports that AML1/ETO gene in children and adolescents is not a favorable prognostic factor.

The hazardous effects of alveolar hypocapnia on lung mechanics during weaning from cardiopulmonary bypass

The bronchoconstrictive effects of alveolar hypocapnia during weaning from cardiopulmonary bypass (CPB) were investigated in patients undergoing elective coronary artery revascularization. Thirty patients were randomly assigned into two equal groups. In both groups, mechanical ventilation was initiated for 3 min prior to weaning from CPB with the venous pressure low. This kept the pulmonary vascular bed empty, resulting in alveolar hypocapnia (ETCO2 < 2 kPa). Peak airway pressure (P(peak)) and plateau pressures (P(plateau)) were recorded. In group 1, 5% CO2 was added to the inspiratory gas mixture and the ETCO2 allowed to rise (ETCO2 > 3.3 kPa). The ventilation pressure measurements were recorded again after 3 min stabilization. In group 2, the venous pressure was increased to allow the pulmonary venous bed to fill and the ventilation pressures recorded after a 3 min period of stabilization. In group 1, the ventilatory pressures dropped significantly (p < 0.001) when the alveolar hypocapnia was reversed with added CO2 (P(peak) 19.71 +/- 5.7 to 12.31 +/- 2.8 cmH2O and P(plateau) 13.15 +/- 3.28 to 9.15 +/- 2.23 cmH2O). In group 2, a similar effect was achieved by allowing filling of the pulmonary vascular bed (P(peak) 17.46 +/- 4.72 to 11.92 +/- 3.03 cmH2O and P(plateau) 13.93 +/- 4.10 to 9.37 +/- 3.00 cmH2O). These results suggest that filling the pulmonary vascular bed prior to initiating ventilation, when weaning from CPB, prevents the otherwise deleterious effects of alveolar hypocapnia, resulting in raised bronchomotor tonus and raised airway pressures.

Prevalence of factor V Leiden in patients with retinal vein occlusion

PURPOSE

Factor V Leiden mutation is a common genetic defect associated with a tendency to venous thrombosis. The aim of this study was to evaluate the prevalence of factor V Leiden in patients with retinal vein occlusion (RVO).

METHODS

Blood samples were obtained from fifty RVO patients and were tested for factor V Leiden using DNA analysis. Twenty-three patients had central RVO (CRVO), twenty-five had branch RVO (BRVO) and two had CRVO in one eye and BRVO in the other eye.

RESULTS

DNA analysis showed that only 4 patients (8%) were heterozygous carriers of factor V Leiden. None of the patients were found to be homozygous. In the control group 11 (9.2%) were heterozygous carriers of factor V Leiden. The difference between the patients and the controls was not statistically significant.

CONCLUSION

There was no clear association between RVO and factor V Leiden in this pool of patients. Factor V Leiden does not seem to play an important role in the development of RVO.

Role of the mutations Trp8 => Arg and Ile15 => Thr of the human luteinizing hormone beta-subunit in women with polycystic ovary syndrome

OBJECTIVE

To evaluate the clinical significance of LH in the form of a mutant beta-subunit in women with polycystic ovary syndrome (PCOS).

DESIGN

Prospective, controlled study.

SETTING

University hospital.

PATIENT(S)

Thirty healthy women and 30 women with PCOS.

INTERVENTION(S)

Clinical, ultrasonographic, and hormonal findings were used to define PCOS. Nucleotide mutations within codons 8 and 15 in the LH beta-subunit gene (Trp8 => Arg and Ile15 => Thr) were analyzed with the use of polymerase chain reaction and subsequent restriction fragment length polymorphism.

MAIN OUTCOME MEASURE(S)

Serum levels of gonadotropins, androgens, E2, and prolactin were determined, and the results of restriction fragment length polymorphism were analyzed.

RESULT(S)

Five women in the control group and one woman in the PCOS group were found to be affected by the LHbeta gene mutations. No difference was observed in serum androgen and E2 levels between the affected women and 25 healthy women who were homozygous for the wild-type LH. However, women whose serum LH levels were < or = 5.1 mIU/mL had a higher risk of having mutant LH.

CONCLUSION(S)

The frequency of LH mutations in women with PCOS is similar to that in healthy women. The presence of the variant does not cause any significant change in serum levels of androgens and E2.

Evaluation of chimerism with DNA polymorphisms in bone marrow transplantation

Evaluation of chimeric status following allogenic BMT is an important tool for monitoring the replacement of host cells with donor cells and for determining the risk of relapse. Polymorphic DNA sequences can be used as powerful markers in identification of donor/recipient genotype differences, even between close relatives. Polymerase chain reaction (PCR) amplification of three variable number of tandem repeat (VNTR) loci and five single-locus polymorphisms (SLP) was used to identify chimerism in 40 recipient-donor pairs. Mixed chimerism was present in 11 patients, and complete chimerism in 29. This PCR method is a rapid and sensitive assay to detect engraftment and evaluate relapse potential, and thus is very useful in the clinical management of BMT patients.

Coagulation factor V gene mutation increases the risk of venous thrombosis in behçet's disease

We investigated the prevalence of the coagulation factor V gene G1691A mutation in 64 patients with Behçet's disease (BD) and in 107 apparently healthy individuals. The mutation was present in the heterozygous state in 37.5% of the patients with a history of deep vein thrombosis (12/32) and in 9.4% of the patients without any thrombotic event (3/32). Eleven healthy individuals were also heterozygous for the mutation (10.3%). The prevalence of the mutation in BD patients with and without thrombosis was significantly different (P = 0.0079). We conclude that the factor V gene mutation may play a major role in the development of venous thrombosis in BD.

Amplification in tumors and benign tissue of breast cancer patients

Inappropriate expression of the c-erb B2 gene has been associated with aggressive tumor behavior in breast cancer. In this study the c-erb B2 amplification was investigated both in the tumors and benign breast tissue of the patients by competitive PCR. The technique combines the sensitivity and speed of PCR with coamplification of a single copy reference gene to achieve quantitative results. Gene copy numbers in excess of 3 copies were observed in tumors of 7 patients but not in the normal tissue samples. We conclude that the increase in the gene copy numbers is a result of the tumorigenic changes occurring in the cancer cell.

Clinical and cytogenetic studies of two cases of Klinefelter syndrome with hereditary retinoblastoma and rhabdomyosarcoma

Two children with Klinefelter syndrome (KS), one associated with bilateral hereditary retinoblastoma (RB) and the other with rhabdomyosarcoma (RMS) are reported. Both were boys and chromosomally mosaic for KS. The hereditary retinoblastoma case yielded 46,XY,del(13)(q12q14.2)/47, XXY(c),del(13)(q12q14.2) in PHA-stimulated lymphocytes. The rhabdomyosarcoma case yielded 46,XY/ 47,XXY(c) in peripheral blood cells whereas tumor revealed trisomy 8, trisomy 7, and t(7;13)(q33;q32) in addition to 46,XY/47,XXyc mosaicism.

Monosomy 7 myeloproliferative disease associated with neurofibromatosis type I: a case report

A 7-year-old girl with neurofibromatosis type I (NF1) was diagnosed to have monosomy 7 myeloproliferative disease (Mo 7-MPD). Of the benign and malignant tumors that are encountered with increased incidence in NF1, those originating from the neural crest are frequent. However, tumors that do not originate from the neural crest may also be seen and among these, myeloid leukemias are prominent. Studies on NF1 patients with Mo 7-MPD and juvenile chronic myeloid leukemia (JCML) have suggested the role of the NF1 gene in the leukemogenesis. The relationship between monosomy 7 and hematological malignancies is already known. These findings are in agreement with the multi-step development theory of cancer. In addition, our case is one of the very rare NF1 cases having father to daughter inheritance with a myeloid malignancy. We believe that cytogenetic and molecular genetic studies will contribute to further understanding of leukemogenesis.