[Variables associated with hematological remission and survival in patients with acute myeloid leukemia after induction failure and relapse]

Objective: This study aimed to explore variables associated with remission rate and survival in patients with acute myeloid leukemia (AML) after induction failure and relapse. Methods: Data of 373 consecutive patients with AML were analyzed after induction failure and relapse. Binary logistics and the Cox model regression were used to identify variables associated with remission rate and outcomes. Results: In patients with AML after induction failure and relapse, the total CR+CRi rates were 50.6% and 40.3%, respectively; among those who achieved CR/CRi, the 3-year RFS rates were 34.4% and 30.4%, respectively, and the 3-year overall survival rates were 40.1% and 31.6%, respectively. In the multivariate analyses, using CLAG or FLAG regimen as a re-induction chemotherapy regimen, age <39 years and SWOG low-risk were significantly associated with higher remission rates in patients with induction failure. Male, secondary AML, SWOG high-risk, the interval from the first remission to relapse within 12 months, and bone marrow blasts ≥20% at the time of relapse were significantly associated with lower remission rates in relapsed patients. Transplantation was significantly associated with prolonged relapse-free survival and overall survival in patients achieving hematologic remission; the SWOG low-risk group was significantly associated with longer overall survival in those with induction failure; and achieving CR (not CRi) or having female gender was associated with longer RFS or overall survival in relapsed patients. Conclusion: Reinduction chemotherapy regimen, age, gender, SWOG risk, secondary AML, the interval from the first remission to relapse, and bone marrow blast percentage at the time of relapse were significantly associated with remission rates in the patients with AML after induction failure and relapse. Transplantation, SWOG low-risk, achieving CR, or female gender were associated with longer survivals in those achieving remission.

[A study on the end criteria of forced vital capacity curve in adults]

Objective: To explore the end criteria of forced vital capacity(FVC) curve in adults. Methods: A multicenter cross-sectional study was performed in Zhongshan Hospital Affiliated to Fudan University, the First Affiliated Hospital of Fujian Medical University, and the Third Affiliated Hospital of Inner Mongolia Medical University from January 2017 to August 2017. A consecutive sample of subjects who completed the spirometry test and FVC curves met end criteria of no volume change (<0.025 L) for ≥ 1 s were qualified in this study. Subjects were divided into a normal group (n=610), an obstructive group (n=536), and a restrictive group(n=306) according to pulmonary function test results. The FET values in different groups were compared. The side effects in the 3 groups and the diagnostic accuracy, specificity and security of different FET in the obstructive group were assessed. Results: The FET values of the normal group, the obstructive group, and the restricted group were (4.00±1.07) s, (8.08±1.56) s and (2.97±0.76) s respectively, and the 95% CI of FET in the 3 groups were between 3.88-4.12 s, 7.02-10.14 and 2.21- 3.73 s (F=2 263.80, P<0.01). When the exhalation platform was used as the standard of FVC curve, the adverse reaction rate in the normal group and the restricted group were 1.1% and 1.3% respectively, lower than the rate of 17.2% in the obstructive group (χ(2)=92.73, χ(2)=48.49 respectively; all P<0.05). In the obstructive group, 7 s as the ending criterion had similar incidence of adverse reactions to 6 s (χ(2)=0.01, P=0.93). With further extension of expiration time, the incidence of adverse reactions increased significantly. In the obstructive group, the sensitivity of FEV(1)/FEV(7) was 99.25%, higher than that at FEV(1)/FEV(6) (χ(2)=4.06, P=0.04), and the specificity of diagnosis was very similar and 100%. Conclusions: FET was variable in subjects with different lung function status. It is not appropriate to use a fixed FET≥ 6 s as the end criterion of spirometry for adults. For patients with normal lung function or restrictive lung function defect, exhalation platform should be used as the end of exhalation standard. For patients with obstructive lung function defect, an FET of up to 7 s is appropriate.

[Effects of artesunate combined with bortezomib on apoptosis and autophagy of acute myeloid leukemia cells in vitro and its mechanism]

Objective: To investigate the effects of artesunate combined with bortezomib on the proliferation, apoptosis and autophagy of human acute myeloid leukemia cell lines MV4-11, and its mechanisms. Methods: MTT method was used to determine the anti-proliferation effect of different concentrations of artesunate, bortezomib and their combination on MV4-11 cells. The cell apoptosis were analyzed by flow cytometry. The expression of cleaved-Caspase-3, Bcl-2 family protein (Bcl-2, Mcl-1, Bim, Bax) and autophagy-related protein LC3B were assayed by Western blot. Results: Artesunate displayed a proliferation inhibition effect on MV4-11 with dose- and time-dependent manner, the IC(50) of artesunate on MV4-11 after 48 hours was 1.44 μg/ml. Bortezomib displayed a proliferation inhibition effect on MV4-11 with dose-dependent manner, the IC(50) of bortezomib on MV4-11 after 48 hours was 8.97 nmol/L. The combination of artesunate (0.75, 1.0 μg/ml) and Bortezomib (6, 8 nmol/L) showed higher inhibition on MV4-11 than artesunate or bortezomib alone in the same concentration gradient after 48 hours (P<0.05) . The cooperation index of the two drugs were all less than 1. The 48 h apoptotic rate of artesunate (1.5 μg/ml) on MV4-11 was (15.27±2.18) %, (19.85±3.23) % of bortezomib (8 nmol/L) , (81.67±5.96) % of combination of the two drugs, significantly higher than the single group (P<0.05) . When combination of the two drugs on MV4-11 after 24 hours, the levels of pro-apoptotic protein Bim and the cleaved activation of Caspase-3 and autophagy-related protein LC3B were up-regulated and the anti-apoptotic protein Bcl-2 expressions was down-regulated. Conclusion: Combination of artesunate with bortezomib shows a significant synergistic effects on proliferation, apoptosis and autophagy of MV4-11 cell lines, which may be associated with Bcl-2 family proteins expression.

Inflammation in lung after acute myocardial infarction is induced by dendritic cell-mediated immune response

The present study was performed to describe the changes of lung tissues in mice with acute myocardial infarction (AMI) and also explain the cell mechanism involved in inflammation in lung. AMI was established by left coronary ligation in mice. Then mice were divided into three groups: control group, MW1 group (sampling after surgery for one week) and MW2 group (sampling after surgery for two weeks). Afterwards, measurement of lung weight and lung histology, cell sorting in bronchoalveolar lavage (BAL) fluid and detection of several adhesive molecules, inflammatory molecules as well as enzyme associated with inflammation were performed. Moreover, dendritic cells (DCs) were isolated from bone marrow of C57B/L6 mice. After incubating with necrotic myocardium, the expression of antigen presenting molecules, co-stimulatory molecules and inflammatory molecules were detected by flow cytometry or immunohistochemistry in DCs. We also detected T-cell proliferation after incubating with necrotic myocardium-treated DCs. AMI induced pathological changes of lung tissue and increased inflammatory cell amount in BAL fluid. AMI also increased the expression of several inflammatory factors, adhesive molecules and enzymes associated with inflammation. CD11c and TLR9, which are DC surface markers, showed a significantly increased expression in mice with AMI. Additionally, necrotic myocardium significantly increased the expression of co-stimulatory factors including CD83 and CD80, inflammatory cytokines including TNF-α, IFN-γ and NF-κB in DCs. Furthermore, DCs treated with necrotic myocardium also significantly promoted T-cell proliferation. AMI induced inflammation in lung and these pathological changes were mediated by DC-associated immune response.

Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay

This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18)  cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43)  cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.

New measurement of antineutrino oscillation with the full detector configuration at Daya Bay

We report a new measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9×10^{5} GW_{th}  ton days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six ^{241}Am-^{13}C radioactive calibration sources reduced the background by a factor of 2 for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of sin^{2}2θ_{13} and |Δm_{ee}^{2}| were halved as a result of these improvements. An analysis of the relative antineutrino rates and energy spectra between detectors gave sin^{2}2θ_{13}=0.084±0.005 and |Δm_{ee}^{2}|=(2.42±0.11)×10^{-3}  eV^{2} in the three-neutrino framework.

Search for a light sterile neutrino at Daya Bay

A search for light sterile neutrino mixing was performed with the first 217 days of data from the Daya Bay Reactor Antineutrino Experiment. The experiment's unique configuration of multiple baselines from six 2.9 GW(th) nuclear reactors to six antineutrino detectors deployed in two near (effective baselines 512 m and 561 m) and one far (1579 m) underground experimental halls makes it possible to test for oscillations to a fourth (sterile) neutrino in the 10(-3) eV(2)<|Δm(41)(2) |< 0.3 eV(2) range. The relative spectral distortion due to the disappearance of electron antineutrinos was found to be consistent with that of the three-flavor oscillation model. The derived limits on sin(2) 2θ(14) cover the 10(-3) eV(2) ≲ |Δm(41)(2)| ≲ 0.1 eV(2) region, which was largely unexplored.

Spectral measurement of electron antineutrino oscillation amplitude and frequency at Daya Bay

A measurement of the energy dependence of antineutrino disappearance at the Daya Bay reactor neutrino experiment is reported. Electron antineutrinos (ν¯(e)) from six 2.9  GW(th) reactors were detected with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls. Using 217 days of data, 41 589 (203 809 and 92 912) antineutrino candidates were detected in the far hall (near halls). An improved measurement of the oscillation amplitude sin(2)2θ(13)=0.090(-0.009)(+0.008) and the first direct measurement of the ν¯(e) mass-squared difference |Δm(ee)2|=(2.59(-0.20)(+0.19))×10(-3)  eV2 is obtained using the observed ν¯(e) rates and energy spectra in a three-neutrino framework. This value of |Δm(ee)2| is consistent with |Δm(μμ)2| measured by muon neutrino disappearance, supporting the three-flavor oscillation model.

Radiopotentiation of human brain tumor cells by sodium phenylacetate

Phenylacetate (PA) inhibits the growth of tumor cells in vitro and in vivo and shows promise as a relatively nontoxic agent for cancer treatment. A recent report shows that prolonged exposure of cells to low concentrations of PA can enhance the radiation response of brain tumor cells in vitro, opening up the possibility of using this drug to improve the radiation therapy of brain tumor patients. We investigated the cytotoxicity produced by sodium phenylacetate (NaPA) alone and in combination with X-rays in SF-767 human glioblastoma cells and in two medulloblastoma cell lines, Masden and Daoy. Exposure of all three cell lines to relatively low concentrations of NaPA for up to 5 days did not enhance the subsequent cell killing produced by X-irradiation. However, enhanced cell killing was achieved by exposing either oxic or hypoxic cells to relatively high drug concentrations ( > 50-70 mM) for 1 h immediately before X-irradiation. Because central nervous system toxicity can occur in humans at serum concentrations of approximately 6 mM PA, translation of these results into clinical trials will likely require local drug-delivery strategies to achieve drug concentrations that can enhance the radiation response. The safety of such an approach with this drug has not been demonstrated.

Distribution of semaphorin IV in adult human brain

The semaphorins comprise a family of secreted and membrane bound proteins that influence development of the nervous system as well as non-neural organs. H.SemaIV was originally isolated from a homozygously deleted region involving a subset of small cell lung cancers, a neuroendocrine derived neoplasm. To investigate H.SemaIV expression, specific polyclonal antibodies directed against a unique polypeptide (amino acids 758-773) were developed and their specificity confirmed. In cell lines, H.SemaIV staining was observed in cytoplasmic granules. In the normal adult human brain, we noted three general characteristics of H.SemaIV expression. H.SemaIV was strongly present in specific nuclei or in neuronal regions arranged in defined subnuclear structures. It was also present in neurons but not glial cells or ependymocytes. Lastly, H.SemaIV was not present in cell bodies, but rather in fibers and nerve terminals. Interestingly, an altered pattern of staining was detected in brains of three patients with Alzheimer's disease.

Genomic organization of the MTM1 gene implicated in X-linked myotubular myopathy

X-linked recessive myotubular myopathy (XLMTM) is a very severe congenital muscular disease characterised by an impaired maturation of muscle fibres, and caused by defects in the MTM1 gene. This gene defines a new family of putative tyrosine phosphatases conserved through evolution. We have determined intronic flanking sequences for all the 15 exons to facilitate the detection of mutations in patients and genetic counselling. We characterised a new polymorphic marker in the immediate vicinity of the gene, which might prove useful for linkage analysis. Sequencing of the TATA-less predicted promoter provides the basis for transcriptional regulatory studies.

Characterization of human glioblastoma xenograft growth in athymic mice

BACKGROUND-MATERIALS-METHODS: We initiated the studies reported in this paper to establish baseline growth data for tumors produced by several human brain tumor cell lines. Female athymic mice were injected with five established human glioblastoma cell lines subcutaneously. We optimized implantation conditions in SF-767 cells by evaluating tumor take and growth characteristics, and resulting growth data were compared to 2 other cell lines.

RESULTS-CONCLUSIONS

Three (SF-767, U-251 MG-NCI, and U-87 MG) of the 5 cell lines produced solid, ellipsoid tumors. For SF-767 cells, the best tumor growth parameters were achieved when 3.0 x 10(6) cells in 0.1 ml medium containing fetal calf serum were injected unilaterally. These conditions produced a high percentage of usable tumors (77.6%) that were detectable approximately 3 days after implantation and reached a size of 100 mm3 in 23 days. Comparison of several growth characteristics of the tumors produced by the 3 cell lines revealed that SF-767 tumors displayed the most uniform growth rates, the fastest doubling times, and the most uniform usable group of tumors (> 100 mm3). U-87 MG and U-251 MG-NCI had a similar histopathologic appearance while SF-767 had a different histology. Our results indicate that these 3 human glioblastoma cells produce flank tumors that exhibit decidedly different growth parameters. We are currently using all 3 of these human brain tumor xenograft models in other in vivo studies.

Cloning and characterization of an alternatively spliced gene in proximal Xq28 deleted in two patients with intersexual genitalia and myotubular myopathy

We have identified a novel human gene that is entirely deleted in two boys with abnormal genital development and myotubular myopathy (MTM1). The gene, F18, is located in proximal Xq28, approximately 80 kb centromeric to the recently isolated MTM1 gene. Northern analysis of mRNA showed a ubiquitous pattern and suggested high levels of expression in skeletal muscle, brain, and heart. A transcript of 4.6 kb was detected in a range of tissues, and additional alternate forms of 3.8 and 2.6 kb were present in placenta and pancreas, respectively. The gene extends over 100 kb and is composed of at least seven exons, of which two are noncoding. Sequence analysis of a 4.6-kb cDNA contig revealed two overlapping open reading frames (ORFs) that encode putative proteins of 701 and 424 amino acids, respectively. Two alternative spliced transcripts affecting the large open reading frame were identified that, together with the Northern blot results, suggest that distinct proteins are derived from the gene. No significant homology to other known proteins was detected, but segments of the first ORF encode polyglutamine tracts and proline-rich domains, which are frequently observed in DNA-binding proteins. The F18 gene is a strong candidate for being implicated in the intersexual genitalia present in the two MTM1-deleted patients. The gene also serves as a candidate for other disorders that map to proximal Xq28.

Cytotoxicity and cell-cycle effects of paclitaxel when used as a single agent and in combination with ionizing radiation

PURPOSE

This study aimed to determine the extent of paclitaxel-induced cytotoxicity and cell-cycle perturbations when used alone and in combination with radiation in human glioma cells.

METHODS AND MATERIALS

The effect of paclitaxel alone on three human glioma cells lines--SF-126, U-87 MG, and U-251 MG--was assessed after 24, 48, 72, or 96 h treatment. For experiments in combination with radiation, cells were exposed to either a long (48-h) or short (8-h) duration of paclitaxel treatment prior to irradiation. Cell survival was determined by clonogenic assay. Cell cycle perturbations were assessed by using flow cytometry to measure the proportion of cells in G1, S, and G2/M phases.

RESULTS

When cells were treated with paclitaxel alone for > or = 24 h, cytotoxicity increased up to a threshold dose, after which it plateaued. When treatment duration was < or = 24 h, cytotoxicity was appreciably greater in U-251 MG cells than in SF-126 and U-87 MG cells. After 24 h of paclitaxel treatment, cells in plateau phase growth had increased survival compared to cells in log phase growth. In contrast, after 8 h paclitaxel treatment, mitotic cells had reduced survival compared to cells from an asynchronous population. Cell-cycle perturbations were consistent with the presence of a mitotic block after paclitaxel treatment, although changes in other cell-cycle phase fractions varied among cell lines. For experiments in combination with radiation, cytotoxicity was increased when cells were irradiated after 48 h of paclitaxel treatment but not after 8 h of treatment.

CONCLUSION

The duration of paclitaxel treatment and the location of cells in the cell cycle modify the degree of radiation cytotoxicity. The mechanisms of paclitaxel cytotoxicity are likely to be multifactorial because varying effects are seen in different cell lines. Furthermore, it is clear that simply increasing the number of cells in G2/M is insufficient in itself to increase the response of cells to radiation.

Identification of a hot spot for microdeletions in patients with X-linked deafness type 3 (DFN3) 900 kb proximal to the DFN3 gene POU3F4

Small mutations in the POU domain gene POU3F4 were recently shown to cause X-linked deafness type 3 (DFN3) in nine unrelated males. The POU3F4 gene was found to be located outside four of five deletions associated with DFN3. Two of these deletions were situated more than 400 kb proximal to POU3F4. Employing PCR analysis of sequence tagged sites from this region we initially identified novel deletions in two DFN3 patients. To investigate this chromosomal segment in more detail, we extended a previously established 850 kb cosmid contig in the centromeric direction to a total size of 1500 kb. Cosmids from this contig were hybridized to DNA of 11 unrelated males with DFN3. In two patients, we identified deletions encompassing the POU3F4 gene and variably sized segments of Xq21.1. In six of the nine remaining patients which lacked mutations in the POU3F4 gene, smaller deletions were identified which, with one exception, overlap in a 8 kb segment 900 kb proximal to the POU3F4 gene. In one patient, we identified several small deletions in the vicinity of the 8 kb DNA segment. Together, deletions account for 56% (13/23) of all known DFN3 mutations, most (10/13) of which do not encompass the POU3F4 gene. The combined molecular data suggest that the deletion hot spot region in Xq21.1 contains another DFN3 gene or, alternatively, a sequence element involved in transcriptional regulation of POU3F4.

X-linked myotubular myopathy: refinement of the gene to a 280-kb region with new and highly informative microsatellite markers

We have recently refined the localization of the myotubular myopathy (MTM1) gene to a 430-kb region between DXS304 and DXS1345 in proximal Xq28. We report two new polymorphic microsatellite markers, DXS8377 and DXS7423, that were physically mapped within the critical interval. A recombination event in a family segregating for MTM1 placed the disease gene telomeric to the trinucleotide polymorphism DXS8377. Together with the recent mapping of two microdeletions associated with MTM1, the recombination refines the critical region to 280 kb. A second recombination event was observed distal to the tetranucleotide repeat DXS7423. This recombination has occurred in the off-spring of a female with a more than 67% probability of being a carrier and very likely restricts the MTM1 gene to a 130-kb region. This physical refinement is significant for positional cloning of the disease gene. The highly polymorphic markers and the precise localization of the MTM1 gene will facilitate genetic diagnosis of the disorder.

A gene mutated in X-linked myotubular myopathy defines a new putative tyrosine phosphatase family conserved in yeast

X-linked recessive myotubular myopathy (MTM1) is characterized by severe hypotonia and generalized muscle weakness, with impaired maturation of muscle fibres. We have restricted the candidate region to 280 kb and characterized two candidate genes using positional cloning strategies. The presence of frameshift or missense mutations (of which two are new mutations) in seven patients proved that one of these genes is indeed implicated in MTM1. The protein encoded by the MTM1 gene is highly conserved in yeast, which is surprising for a muscle specific disease. The protein contains the consensus sequence for the active site of tyrosine phosphatases, a wide class of proteins involved in signal transduction. At least three other genes, one located within 100 kb distal from the MTM1 gene, encode proteins with very high sequence similarities and define, together with the MTM1 gene, a new family of putative tyrosine phosphatases in man.

Prenatal diagnosis of X-linked myotubular myopathy: strategies using new and tightly linked DNA markers

X-linked myotubular myopathy (MTM1) is a severe congenital myopathy characterized by hypotonia, muscle weakness, and associated respiratory insufficiency. Perinatal death is common. The disease locus was shown to be linked to polymorphic markers in Xq28 and we have recently refined the MTM1 locus to a physical region of less than one megabase (Mb) at proximal Xq28. Two new microsatellite markers were developed and assigned in the MTM1 candidate region. We applied them and other DNA markers for prenatal diagnosis in two families. In one case, an affected fetus was predicted and a recombination event was observed with two more distal markers in the region. The second fetus was born unaffected as predicted. The new DNA markers and the precise location of the MTM1 gene provide an improvement for early prenatal diagnosis of the disease. We present suggestions for different combinations of linked and flanking DNA markers for maximal informativeness and accuracy.

Deletions in Xq28 in two boys with myotubular myopathy and abnormal genital development define a new contiguous gene syndrome in a 430 kb region

We have recently described a female patient with myotubular myopathy (MTM1) and an interstitial deletion at Xq28. Characterisation of the deletion allowed us to position the MTM1 gene to a 600 kb region between DXS304 and DXS497. In order to further restrict the region we screened for deletions in a set of 38 patients. We found two overlapping deletions in boys that in addition to MTM1 showed an unexpected abnormal genital development. As the latter phenotype is not found in the other non-deleted MTM1 patients, our observations are best explained by a contiguous gene syndrome. The deletions define a 430 kb region that contains the MTM1 gene and most likely a gene implicated in male sexual development. A high resolution physical map of this region is presented.

Myotubular myopathy in a girl with a deletion at Xq27-q28 and unbalanced X inactivation assigns the MTM1 gene to a 600-kb region

A young girl with a clinically moderate form of myotubular myopathy was found to carry a cytogenetically detectable deletion in Xq27-q28. The deletion had occurred de novo on the paternal X chromosome. It encompasses the fragile X (FRAXA) and Hunter syndrome (IDS) loci, and the DXS304 and DXS455 markers, in Xq27.3 and proximal Xq28. Other loci from the proximal half of Xq28 (DXS49, DXS256, DXS258, DXS305, and DXS497) were found intact. As the X-linked myotubular myopathy locus (MTM1) was previously mapped to Xq28 by linkage analysis, the present observation suggested that MTM1 is included in the deletion. However, a significant clinical phenotype is unexpected in a female MTM1 carrier. Analysis of inactive X-specific methylation at the androgen receptor gene showed that the deleted X chromosome was active in approximately 80% of leukocytes. Such unbalanced inactivation may account for the moderate MTM1 phenotype and for the mental retardation that later developed in the patient. This observation is discussed in relation to the hypothesis that a locus modulating X inactivation may lie in the region. Comparison of this deletion with that carried by a male patient with a severe Hunter syndrome phenotype but no myotubular myopathy, in light of recent linkage data on recombinant MTM1 families, led to a considerable refinement of the position of the MTM1 locus, to a region of approximately 600 kb, between DXS304 and DXS497.

X linked myotubular myopathy (MTM1) maps between DXS304 and DXS305, closely linked to the DXS455 VNTR and a new, highly informative microsatellite marker (DXS1684)

The locus for X linked recessive myotubular myopathy (MTM1) has previously been mapped to Xq28 by linkage analysis. We report two new families that show recombination between MTM1 and either DXS304 or DXS52. These families and a third previously described recombinant family were analysed with two highly polymorphic markers in the DXS304-DXS52 interval, the DXS455 VNTR and a newly characterised microsatellite, DXS1684 (82% heterozygosity). These markers did not recombine with MTM1 in the three families. Together with the recent mapping of an interstitial X chromosome deletion in a female patient with moderate signs of myotubular myopathy, our data suggest the following order of loci in Xq28: cen-DXS304-(DXS455, MTM1)-DXS1684-DXS305-DXS52-tel. This considerably refined localisation of the MTM1 locus should facilitate positional cloning of the gene. The availability of highly polymorphic and very closely linked markers will markedly improve carrier and prenatal diagnosis of MTM1.

Radiopotentiation of human brain tumor cells by the spermine analog N1,N14-bis(ethyl)homospermine

PURPOSE

To determine whether the cytotoxicity produced by radiation can be increased by the spermine analog N1,N14-bis(ethyl)homospermine (BE-4-4-4).

METHODS AND MATERIALS

Two human tumor cell lines, SF-126 and U-251 MG, were either treated with 0.1 or 0.4 microM BE-4-4-4 for 3 or 4 days, or with 0.2 microM BE-4-4-4 for 4 days. At the end of BE-4-4-4 treatment, cells were irradiated and assayed immediately. Polyamine levels, cell survival, and cell number were determined.

RESULTS

In SF-126 cells, treatment with 0.2 microM BE-4-4-4 for 4 days killed about 50% of the cells and also increased the cytotoxicity of radiation. The dose enhancement ratio was approximately 1.3:1.5, which is similar to that reported for alpha-difluoromethylornithine. Polyamine levels were partially depleted, and growth was inhibited to about 60% of control levels. Pretreatment of cells with either 0.1 or 0.4 microM BE-4-4-4 for 3 or 4 days produced less of an increase in radiation-induced cytotoxicity, even though these exposures killed 30-40% or 60-90% of the cells, respectively. Similar treatment with 0.1-0.4 microM BE-4-4-4 in U-251 MG cells had minimal effects on cytotoxicity and growth inhibition, while treatment with 1.0 microM and 2.0 microM BE-4-4-4 for 4 days produced more than a 50% depletion in polyamine levels and partial inhibition in growth, but failed to demonstrate radiopotentiation.

CONCLUSION

The cytotoxic polyamine analog BE-4-4-4 can increase the cytotoxicity caused by radiation in at least one cell line. The amount of potentiation depends on the concentration of the analog, with the most occurring at the intermediate concentration. Because we did not observe potentiation in both cell lines, and because of the dose dependence seen in SF-126 cells, the clinical efficacy produced by combined BE-4-4-4 and radiation protocols may be limited.

Non-specific X-linked mental retardation: linkage analysis in MRX2 and MRX4 families revisited

We have previously reported linkage analysis in 3 families with non-specific X-linked mental retardation (XLMR). This used RFLPs and was limited by the relatively low informativeness and density of markers available. We have performed a new linkage analysis using microsatellites (including new Genethon markers) in the two most informative families. In the MRX2 family, a lod score of 2.61 at theta = 0.05 had previously been obtained with DXS85 in Xp22.2. We now report a tighter linkage with AFM 135xe7 (DXS989, z = 4.62 at theta = 0.00) and established the order DXS85-DXS207-DXS999 (AFM234 y12)-MRX2, DXS365, DXS1052 (AFM 163yh2), DXS989-DXS1065 (AFM224zf2), DMD 3'. The localization of MRX2 in Xp22.2-p22.1 is thus clearly different from the more distal MRX gene defined by patients with contiguous gene syndromes. In the MRX4 family, a maximum lod score of 2.53 at theta = 0.00 had been obtained with DXS159 in Xq13. Our present study did not show recombination from ALAS2 in Xp11.21 to DXS441 in Xq13.3 (z = 3.38 at theta = 0.00 for the latter marker) and the closest flanking markers are DXS255 in Xp11.22 and DXYS1 in Xq21.3. Reduced recombination around the centromere prevents precise mapping. The localisation of MRX4 overlaps with that of several other MRX families.

Shift-invariant photorefractive joint-transform correlator using Fe:LiNbO(3). crystal plates

We report the results of our experimental investigation on a shift-invariant photorefractive image correlator that uses a thin crystal plate of Fe:LiNbO(3), which operates in the Raman-Nath regime of diffraction.

The effect of valproic acid on sister chromatid exchange aberration frequency in epileptic children

Sister chromatid exchange (SCE) and chromosome aberration have been used to examine the peripheral lymphocytes of 20 epileptic children on 6-52 months monotherapy with valproic acid (VPA), and two matched control groups were set for comparison. The frequency of SCE in the VPA treated group is significantly higher than two control groups (P less than 0.01). It seems that the increase in SCE frequency is not related to epilepsy. SCE was also examined in 10 epileptic children before and after intake of only sodium valroat for 6-7 months, there was statistically significant change of SCE following VPA. 9 normal children's lymphocytes were exposed in vitro to sodium valproate (5-20 micrograms/ml), all showed a significant increase in SCE. These results suggested that VPA and its derivatives could damage the DNA of child users; however slightly higher rates of chromosome aberration were not significantly different from two control groups.

The effect of valproic acid on SCE and chromosome aberrations in epileptic children

Sister-chromatid exchange (SCE) and chromosome aberrations have been studied in peripheral lymphocytes of 20 epileptic children treated in monotherapy with valproic acid (VPA) for 6-52 months and in 2 matched control groups. The frequencies of SCE in the VPA-treated epileptic children were significantly higher than in the 2 control groups (p less than 0.01); rates of chromosome aberrations were slightly higher but not significantly different from the 2 control groups. We also examined SCE in 10 epileptic children before and after they took sodium valproate for 6-7 months; there was a statistically significant change in SCE following VPA. 9 normal children whose lymphocytes were exposed in vitro to sodium valproate (5-20 micrograms/ml) showed a significant increase in SCE.