فهرست مطالب

Sciences, Islamic Republic of Iran - Volume:16 Issue: 3, 2006
  • Volume:16 Issue: 3, 2006
  • تاریخ انتشار: 1385/06/13
  • تعداد عناوین: 12
  • Balanced Chromosomal Translocations of Parents in Relation to Spontaneous Abortions
    M. Hassanzadeh Nazarabadi, * R. Raoofian, R. Abutorabi Page 10
    The most significant complication of pregnancy is recurrent miscarriage. Numerous factors have been described as associations with recurrent wastage such as: uterine abnormalities, immunological factors, endocrinologic imbalance and chromosomal defects. Cytogenetic evaluation of couples with recurrent pregnancy losses is performed on the basis of G-banding technique only after other possible etiologic factors have been excluded. The purpose of this study was to determine the frequency of balanced translocation in 153 couples who were introduced to the medical genetic laboratory by gynecologists. The prevalence of balanced chromosomal translocation was 9.8% among which 3.3% appeared with Robertsonian translocation and the remaining (6.5%) was evident with different type of balanced chromosomal rearrangement. The yield of positive results for balanced chromosomal translocation carrier was lower than that expected. With regard to the low incidence of balanced translocation in normal population and high cost and time-consumption of chromosomal analysis cytogenetic investigation should be suggested only in couples with recurrent spontaneous abortions when clinical data fail to clarify the cause
  • J. Raheb, * A.A. Karkhane, S. Naghdi, K.P. Flint Page 209
    A one kb portion of the rpoS gene from Flexibacter chinensis was isolated by PCR, sequenced and compared to the rpoS gene of a variety of other organisms. The gene was found to be 98% similar to previously sequenced genes. Mutation of the rpoS gene with tri-parental mating produced strain JR101 and the growth rate of the mutant was compared with that of the wild-type. The mutant grew slower, and produced longer cells in the stationary phase. The cell size of the mutant was not reduced during the stationary phase, suggesting that cell division was inhibited during the stationary phase. The mutant also showed a much reduced survival under starvation conditions compared to the wild-type strain.
  • S.A. Sadat Noori*, M. Harati Page 217
    Hybrid populations (F3) derived from cross between four moderate salt-resistant spring wheat (Triticum aestivum L.) were assessed for transgressive segregation of salt-tolerant genotypes allowing germination and emergence at 350 mM NaCl for 30 days. The achieved Selection intensity was the order of 0.24-0.27 in these segregation populations (22-25 seedlings from 9000 seeds). Assessment of transgrassive individuals (more salt tolerant) and their parents was carried out in a hydroponics experiment applying six salt concentrations of 150, 200, 225, 250, 275 and 300 Mm NaCl. Root lengths of two-week-old seedlings grown in the different concentrations were used as salt-tolerant criteria. Root length of transgressive plants were longer than parents (except Tobari 66) showing more tolerance to NaCl. It may be assumed that the character in quantitative trait based, and the parents of such hybrids may contain different genes for salt tolerance.
  • R. Salehi, * M. Salehi, A.R. Moafi, Y. Ghaisari, P. Karimian Page 223
    Acute leukemia is the most common malignancy in children accounting for approximately one-third of all childhood cancers. Modern treatment protocols lead to complete remission (CR) in a considerable proportion of patients with lymphoproliferative disorders. However, many of these patients ultimately relapse, showing that in spite of clinical CR still significant amounts of residual malignant cells persist. Various protocols like cytogenetic, molecular and immunological techniques that are more sensitive than morphology are increasingly used to assess and quantify minimal residual disease (MRD). These techniques produce different levels of sensitivity allowing detection of MRD between 10−2-10−6. In this study we have assessed the feasibility of fluorescent PCR in MRD detection and quantification using immunoglobuline heavy chain (IgH) gene rearrangement. Bone marrow samples obtained from 40 patients with precursor-B cell ALL after induction, consolidation, reconsolidation and intensification therapy. Analysis of clonally rearranged IgH gene carried out by CDR3 amplification in presence of an internal competitor with known copy number. After induction therapy 53% of the patients who were considered to be in clinical remission phase still had detectable MRD. After consolidation therapy 43% of the patients were MRD positive. Subsequent to maintenance-2 or intensification therapy still in 30% of patients MRD was observed.
  • A. Vahdati, M. Adib, T. Afrooz, Sh. Kashfi Page 229
    Erythropoietin (EPO) was first known as a factor for red blood cell proliferation and differentiation. Recent studies show the effects of EPO on immune system. In this study the antihuman leukocyte antibody (anti-HLA) titer were determined in five groups of rats، which had been sensitized with human lymphocyte. Also، the effects of stimulation''s frequency and dose of recombinant human erythropoietin (rHuEPO) on anti-HLA antibody titer were studied. Two groups of rats received 20 and 100 IU/kg rHuEPO respectively، after twice sensitization with human lymphocyte. The other two groups were given 20 and 100 IU/kg rHuEPO، but after three times sensitization with human lymphocyte. Control group did not receive rHuEPO. Microlymphocytotoxicity method was used to detect anti-HLA antibodies. The results show that the anti-HLA antibody titer has been decreased significantly compared to control group. This statistically significant decrease was seen in groups، which received 100 IU/kg rHuEPO، and also in those، which received 20 IU/kg after 2 antigenic stimulations. This could be due to the effects of rHuEPO on the number or the activity of B cells and T cells. Moreover، the dose of rHuEPO، length of treatment and the level of sensitization with human lymphocyte might affect anti-HLA antibody titer.
  • S. Vallian, * M.R. Khazaei, F. Karimzadeh Page 233
    Rapid and in time diagnosis of phenylketonuria (PKU) in affected infants can help preventing the progress of mental and developmental disorders associated with the disease. Here we report the isolation of alkaliphilic Bacillus bacteria capable of producing high level of Phenylalanine dehydrogenase (PheDH) from soil. A new quantitative and rapid test for PKU diagnosis was then developed using the isolated bacteria. The bacterial cells were used to convert serum Phenylalanine to phenyl-pyrovic acid، which was measured quantitatively using spectrophotometer. Application of the method in diagnosis of PKU patients in parallel with the HPLC method produced essentially similar results. However، the cost per sample (10-20 cents per sample) using this new method was much less than that of the HPLC method. The method can be automated which is suitable for mass screening for PKU in populations in which funding is a limiting factor.
  • M.H. Karimpour*, A. Malekzadeh Shafaroudi Page 239
    The massive sulfide of Taknar deposits are part of meta volcanic-sedimentary complex (Taknar Formation, Ordovician) and consist of clastic sediments, carbonate, felsic and mafic volcanic and sub-volcanic rocks. The Taknar polymetal deposit shows good layering; therefore it is syngenetic in origin. Taknar zone was affected by low grade metamorphism (Green Schist facies) in the late Paleozoic. As a result, pelitic and subarkosic rocks were changed to sericite or sericite-chlorite schist. Taknar deposit is situated within Taknar zone which is an allochthonous block. This block is situated between two major faults, Drouneh Fault to the south and Rivash (Taknar) Fault to the north. These deposits which are called Tak-I, II, III, and IV, originally were part of one big deposit but due to faulting they are being truncated and moved at least 1 km from each other. Three types of mineralization such as layered, massive and stockwork are present. The layered section is composed of alternating layers of pyrite, chalcopyrite, magnetite, sphalerite, galena and chlorite. The Individual sulphide layers range in thickness from millimeters to 2 cm. Chlorite is the dominate silicate mineral within the layered ore. Massive ore horizons, having >50% magnetite, occur at the stratigraphic top of the mineralized zone. Major minerals are: magnetite + pyrite + chalcopyrite + sphalerite ± galena + chlorite ± quartz ± sericite ± calcite. Pyrite and chalcopyrite content are higher in the lower layers and magnetite, sphalerite and galena are higher within the upper layers. In stockwork mineralization, major minerals are: pyrite + chalcopyrite ± magnetite + quartz + chlorite + sericite ± calcite. Chemical variations of some elements in different deposit are: Tak-I: Cu=0.01-5.86%, Zn=269-15600 (ppm), Pb=27-4400 (ppm), Au=0.86-7 (ppm), Ag=2-95 (ppm), Bi=34-2200 (ppm), and Mo=85-1300 (ppm). Tak-II: Cu=0.33-2.56%, Zn=0.3-7.7%, Pb=93-5000 (ppm), Au=0.33-11 (ppm), Ag=19-105 (ppm), Bi=79-214 (ppm), and Mo=54-116 (ppm). Tak-III: Cu=0.05-5.54%, Zn=62-179 (ppm), Pb=17-47 (ppm), Au=0.06-0.33 (ppm), Ag=2-40 (ppm), and Bi=11-250 (ppm). Based on paragenesis, alteration, style of mineralization, petrography, geochemistry, and structure, Taknar is a new type of magnetite rich polymetal volcanic massive sulfide deposit. Lack of pyrrhotite and high magnetite associated with sulfide minerals make this deposit very different from other VMS deposit. Based on the mineral paragenesis the estimated physiochemical conditions of formation are: Tak-I: T °C ≥ 250, Log f O2=(-29) to (-30), pH=5-7. Tak-II: T °C ≤ 250, Log f S2=(-11) to (-12), Log f O2=(-36) to (-39), 59. Tak-III: T °C ≥ 270, Log f O2=(-28) to (-29), pH>5.
  • H. Doosti*, H.A. Niroumand Page 255
    We propose a wavelet based stochastic regression function estimator for the estimation of the regression function for a sequence of pairwise negative quadrant dependent random variables with a common one-dimensional probability density function. Some asymptotic properties of the proposed estimator are investigated. It is found that the estimators have similar properties to their counterparts studied earlier in literature.
  • H.R. Nili Sani, * M. Amini, A. Bozorgnia Page 261
    In this paper، we discuss strong laws for weighted sums of pairwise negatively dependent random variables. The results on i. i. d case of Soo Hak Sung [9] are generalized and extended.
  • N. Sanjari Farsipour Page 267
    In this paper, we consider admissible estimation of the parameter λr in the gamma distribution with truncated parameter space under entropy loss function. We obtain the classes of admissible estimators. The result can be applied to estimation of parameters in the normal, lognormal, pareto, generalized gamma, generalized Laplace and other distributions.
  • H. Raeisian Amiri*, F. Ebrahimi Page 271

    In this paper, using the tight-binding model, we extend the real-space renormalization group method to time-dependent Hamiltonians. We drive the time-dependent recursion relations for the renormalized tight-binding Hamiltonian by decimating selective sites of lattice iteratively. The formalism is then used for the calculation of the local density of electronic states for a one dimensional quantum wire with time-dependent random potential. Specifically, we study the electronic densities of states of a single and chains of quantum dots connected to two noisy leads.

  • P.K. Shrivastava, * N. Singh, D.P. Tiwari Page 277
    Solar flare events of high importance were utilised to study solar latitudinal frequency distribution of the solar flares in northern and southern hemisphere for the solar cycle 22 to recent solar cycle 23. A statistical analysis was performed to obtain their relationship with sudden storm commencement (SSCs) and Forbush decrease events (Fd) of cosmic ray intensity. An 11-year cyclic variation pattern was seen in occurrence of number of events for solar flares, SSCs and Fds. It was noted that number of solar flares (Fd associated) occurred in southern hemisphere was larger as compared to that in northern hemisphere for the solar cycle 22. Situation reversed, as we associated SSCs and Fds. Northern hemisphere was found more active for the solar cycle 23.