Characterisation of MCP-600D and MCP-700D thermoluminescence detectors and their applicability for photoneutron detection

This paper presents the characteristics of two high-sensitive LiF:Mg,Cu,P thermoluminescence detectors (TLDs) named MCP-600D and MCP-700D [thermoluminescence detector (TLD) Poland]. Furthermore, the applicability of both detectors used as a paired system for photoneutron detection in a high-energy photon field at a linear accelerator is shown. For MCP-600D and MCP-700D, the batch homogeneity is within 22 and 14%, respectively (2 SD). Correction for the individual response of each TLD leads to a reproducibility of 5 and 4%, respectively Both TLD types reveal a linear detector response to dose up to 4 Gy. The energy dependence for both is within 2% for 4 and 6 MV photons. For a 15 MV photon beam, the MCP-600D shows a higher response (10%); compared with the MCP-700D (2%). The MCP-600D is capable of detecting extra doses due to photoneutrons in a 15 MV photon exposure; however, the signal for an open field of the used linear accelerator is in the order of the reproducibility. Using a kind of albedo technique allows detection of photoneutrons in the open photon field anyhow. The neutron detection limit is 10 microGy neutron dose per 1 Gy photon dose. Reproducibility of the TLDs, however, requires more than 10 detectors to determine results with an uncertainty of <5%.

Association between oral antidiabetic use, adverse events and outcomes in patients with type 2 diabetes

OBJECTIVE

To quantify adverse events (AEs) associated with the use of metformin (MET), sulphonylureas (SUs) and thiazolidinediones (TZDs) in a usual care setting, and to assess the relationship of AEs to treatment patterns and glycaemic response in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

An electronic medical record database was used to identify patients with type 2 diabetes age >or=18 years from 1996 to 2005. Patients naïve to oral antidiabetic therapy were followed for 395 days postinitiation of MET, SU or TZD treatment. AEs related to study drugs were evaluated during the follow-up period. Baseline and follow-up A1C levels were compared by drug regimen. Associations between the change in A1C, drug regimen changes and AEs were evaluated.

RESULTS

A total of 14,512 patients (mean age 60.8 years, 52.9% female) were identified. During the follow-up period, 12.7% of patients experienced an AE (8.6% MET, 15.9% SU and 19.8% TZD patients). SU and TZD patients were more likely to experience an AE than MET (p < 0.001) patients. AEs did not significantly influence A1C outcomes, although MET and SU patients experiencing an AE were more likely to add-on therapy (odds ratio (OR) = 1.34 and OR = 1.37, respectively; p < 0.05) than those without an AE. MET patients with AEs were more likely to switch therapy (OR = 1.91; p < 0.05) than those without an AE.

CONCLUSIONS

The occurrence of AEs did not significantly impact glycaemic response to therapy. However, AEs may lead to greater treatment switches for patients receiving MET and add-on therapy for MET-treated and SU-treated patients.

Comparison of variance estimation approaches in a two-state Markov model for longitudinal data with misclassification

We examine the behaviour of the variance-covariance parameter estimates in an alternating binary Markov model with misclassification. Transition probabilities specify the state transitions for a process that is not directly observable. The state of an observable process, which may not correctly classify the state of the unobservable process, is obtained at discrete time points. Misclassification probabilities capture the two types of classification errors. Variance components of the estimated transition parameters are calculated with three estimation procedures: observed information, jackknife, and bootstrap techniques. Simulation studies are used to compare variance estimates and reveal the effect of misclassification on transition parameter estimation. The three approaches generally provide similar variance estimates for large samples and moderate misclassification. In these situations, the resampling methods are reasonable alternatives when programming partial derivatives is not appealing. With smaller chains or higher misclassification probabilities, the bootstrap method appears to be the best choice.

G(2) chromosomal radiosensitivity in Danish survivors of childhood and adolescent cancer and their offspring

In order to investigate the relationship between chromosomal radiosensitivity and early-onset cancer, the G(2) chromosomal radiosensitivity assay was undertaken on a group of 23 Danish survivors of childhood and adolescent cancer, a control group comprising their partners and a group of 38 of their offspring. In addition, the previously reported in-house control group from Westlakes Research Institute (WRI) was extended to 27 individuals. When using the 90th percentile cutoff for the WRI control group, the proportion of individuals with elevated radiosensitivity was 11, 35, 52 and 53% for the WRI control, partner control, cancer survivor and the offspring groups, respectively, with significant differences between the WRI control group and the cancer survivor group (P=0.002) and the offspring group (P<0.001). However, while the comparisons with the WRI control group support an association of chromosomal radiosensitivity with cancer predisposition, when the partner control group was used to define the radiosensitivity cutoff point, no significant differences in radiosensitivity profiles were found between the partner control group and either the cancer survivor group or the offspring group. The failure to distinguish between the G(2) aberration profiles of the apparently normal group of partners and the cancer survivor group suggests that any association with cancer should be viewed with caution, but also raises questions as to the suitability of the partners of cancer survivors to act as an appropriate control group. Heritability of the radiosensitive phenotype was examined by segregation analysis of the Danish families and suggested that 67.3% of the phenotypic variance of G(2) chromosomal radiosensitivity is attributable to a putative major gene locus with dominant effect.

Haplotype diversity in 11 candidate genes across four populations

Analysis of haplotypes based on multiple single-nucleotide polymorphisms (SNP) is becoming common for both candidate gene and fine-mapping studies. Before embarking on studies of haplotypes from genetically distinct populations, however, it is important to consider variation both in linkage disequilibrium (LD) and in haplotype frequencies within and across populations, as both vary. Such diversity will influence the choice of "tagging" SNPs for candidate gene or whole-genome association studies because some markers will not be polymorphic in all samples and some haplotypes will be poorly represented or completely absent. Here we analyze 11 genes, originally chosen as candidate genes for oral clefts, where multiple markers were genotyped on individuals from four populations. Estimated haplotype frequencies, measures of pairwise LD, and genetic diversity were computed for 135 European-Americans, 57 Chinese-Singaporeans, 45 Malay-Singaporeans, and 46 Indian-Singaporeans. Patterns of pairwise LD were compared across these four populations and haplotype frequencies were used to assess genetic variation. Although these populations are fairly similar in allele frequencies and overall patterns of LD, both haplotype frequencies and genetic diversity varied significantly across populations. Such haplotype diversity has implications for designing studies of association involving samples from genetically distinct populations.

Modelling ground vibration from railways using wavenumber finite- and boundary-element methods

A mathematical model is presented for ground vibration induced by trains, which uses wavenumber finite- and boundary-element methods. The track, tunnel and ground are assumed homogeneous and infinitely long in the track direction ( x -direction). The models are formulated in terms of the wavenumber in the x -direction and discretization in the yz -plane. The effect of load motion in the x -direction is included. Compared with a conventional, three-dimensional finite- or boundary-element model, this is computationally faster and requires far less memory, even though calculations must be performed for a series of discrete wavenumbers. Thus it becomes practicable to carry out investigative study of train-induced ground vibration. The boundary-element implementation uses a variable transformation to solve the well-known problem of strongly singular integrals in the formulation. A ‘boundary truncation element’ greatly improves accuracy where the infinite surface of the ground is truncated in the boundary-element discretization. Predictions of vibration response on the ground surface due to a unit force applied at the track are performed for two railway tunnels. The results show a substantial difference in the environmental vibration that could be expected from the alternative designs. The effect of a moving load is demonstrated in a surface vibration example in which vibration propagates from an embankment into layered ground.

The dystrophin associated protein complex in zebrafish

Many cases of muscular dystrophy in humans are caused by mutations in members of the dystrophin associated protein complex (DAPC). Zebrafish are small vertebrates whose bodies are composed predominantly of skeletal muscle, making them attractive models for studying mammalian muscle disorders. Potential orthologs to most of the human DAPC proteins have been found in zebrafish by database screening. Expression of the sarcoglycans, dystroglycan and dystrophin has been confirmed by western blotting. Immunohistochemical and biochemical techniques localize these proteins to the muscle cell membrane in adult zebrafish. Morpholino (MO) experiments designed to inhibit the translation of dystrophin mRNA produce juvenile zebrafish that are less active than zebrafish injected with control morpholinos. Western blot analysis of the dystrophin morpholino-injected zebrafish shows concurrent reduction of dystrophin and the sarcoglycans, suggesting that these proteins, like those in mammals, are part of a complex whose integrity is dependent on dystrophin expression. These results indicate that the zebrafish is an excellent animal model in which to approach the study of dystrophin and its associated proteins.

The LN54 radiation hybrid map of zebrafish expressed sequences

To increase the density of a gene map of the zebrafish, Danio rerio, we have placed 3119 expressed sequence tags (ESTs) and cDNA sequences on the LN54 radiation hybrid (RH) panel. The ESTs and genes mapped here join 748 SSLp markers and 459 previously mapped genes and ESTs, bringing the total number of markers on the LN54 RH panel to 4226. Addition of these new markers brings the total LN54 map size to 14,372 cR, with 118 kb/cR. The distribution of ESTs according to linkage groups shows relatively little variation (minimum, 73; maximum, 201). This observation, combined with a relatively uniform size for zebrafish chromosomes, as previously indicated by karyotyping, indicates that there are no especially gene-rich or gene-poor chromosomes in this species. We developed an algorithm to provide a semiautomatic method for the selection of additional framework markers for the LN54 map. This algorithm increased the total number of framework markers to 1150 and permitted the mapping of a high percentage of sequences that could not be placed on a previous version of the LN54 map. The increased concentration of expressed sequences on the LN54 map of the zebrafish genome will facilitate the molecular characterization of mutations in this species.

Conformational and functional significance of residue proline 17 in chicken muscle adenylate kinase

The effect of mutation proline 17 on the multiple conformations and catalytic function in chicken muscle adenylate kinase (AK) has been studied. The substitution of proline 17 with glycine or valine altered the distribution of multiple conformations. Compared with the wild-type enzyme, the P17G and P17V mutants contained decreased fraction of minor conformer from 18% to 9% and 11%, respectively. Due to the mutation, the enzyme showed lower secondary structural content, poorer affinity to substrates or substrate analogues, and reduced catalytic efficiency. The results revealed the significance of proline 17 in the conformation and function of AK.

[Cloning of the mouse Doc-1R gene by genomic walking]

OBJECTIVE

To obtain the genomic sequences of the mouse Doc-1R gene.

METHODS

Gene-specific primers were designed and synthesized based on the cDNA sequences of the mouse Doc-1R gene. With the use of genomic walking strategy, the mouse genomic walking library was amplified by the polymerase chain reaction(PCR). Mouse genomic library constructed with a special adaptor was utilized as a template to amplify the desired fragment by nested PCR.

RESULTS

A desired fragment of 1.5 kb was obtained. Sequence analysis of the desired fragment confirmed that the genomic cloning of the Doc-1R gene was successful. This gene contains four exons and three introns. All of the splice donor/acceptor site sequences are in accordance with the consensus 'GT-AG' rule.

CONCLUSION

The genomic walking strategy is simple, efficient and reliable; it is an ideal method of cloning genomic fragments.

Modeling and analysis of the structure of the thermostable catechol 2,3-dioxygenase from Bacillus Stearothermophilus

The three-dimensional structure of thermostable catechol 2,3-dioxygenase(TC230) from Bacillus Stearothermophilus has been modeled basing on the known x-ray structure of catechol 2,3-dioxygenase(metapyrocatechase) from Pseudomonas putida mt-2, using computer graphics energy minimization techniques. The rationality of the resulting model was validated by Ramachandran plot and Profile-3D. The structure-functionally important residues, such as M++ binding residues and the substrate binding residues, were identified from the model. These residues are candidates for further site-directed mutagenesis experiments. The reason that the thermostability of TC230 is greater than metapyrocatechase(MPC) has been found, which may be due to the specific structure of the TC230 in the C-end mainly.

Methylcobalamin as antagonist to transient ototoxic action of gentamicin

The objective of this study was to determine whether methylcobalamin inhibits the ototoxic action of gentamicin. Fourteen pigmented guinea pigs were randomly divided into experimental and control groups. Each animal in the experimental group was given a large single dose of gentamicin (125 mg/kg i.m.), followed by immediate administration of methylcobalamin (1 mg kg i.m.). In the control group, the animals received gentamicin only, at the same dose as the experimental group. The compound action potentials (CAPs) in the right ears of animals were measured using a signal processor before and 15, 30, 45, 60 and 75 min after injection of the drugs. The sound stimulus was presented by means of clicks and tone pips at 2, 4 and 8 kHz. Following the electro-physiological tests, the animal was sacrificed and prepared for scanning electron microscopic observation. There was prolongation of latency and diminution of amplitude of CAPs N1 and N2 15 min after injection of gentamicin. Although the N1-N2 intervals increased as the time after injection of gentamicin increased, the variations were still within normal ranges. In contrast, there was no prolongation of N1 latencies or N1-N2 intervals 30 min after injection in the experimental group. There were no marked changes in N1 or N2 amplitudes, compared with the results before injection, in the experimental group. The firing mechanism of the inner ear may be affected by a single dose of gentamicin. This suggests that the transient ototoxic action of gentamicin hardly affected the conductive function of the nerve fibres, even though the firing function of the inner ear was influenced. Methylcobalamin may inhibit the ototoxic side effects of gentamicin.

Activation of mitogen-activated protein kinases is required for alpha1-adrenergic agonist-induced cell scattering in transfected HepG2 cells

Activation of alpha1B-adrenergic receptors ((alpha1B)AR) by phenylephrine (PE) induces scattering of HepG2 cells stably transfected with the (alpha1B)AR (TFG2 cells). Scattering was also observed after stimulation of TFG2 cells with phorbol myristate acetate (PMA) but not with hepatocyte growth factor/scatter factor, epidermal growth factor, or insulin. PMA but not phenylephrine rapidly activated PKCalpha in TFG2 cells, and the highly selective PKC inhibitor bisindolylmaleimide (GFX) completely abolished PMA-induced but not PE-induced scattering. PE rapidly activated p44/42 mitogen-activated protein kinase (MAPK), p38 MAPK, c-Jun N-terminal kinase (JNK), and AP1 (c-fos/c-jun). Selective blockade of p42/44 MAPK activity by PD98059 or by transfection of a MEK1 dominant negative adenovirus significantly inhibited the PE-induced scattering of TFG2 cells. Selective inhibition of p38 MAPK by SB203850 or SB202190 also blocked PE-induced scattering, whereas treatment of TFG2 cells with the PI3 kinase inhibitors LY294002 or wortmannin did not inhibit PE-induced scattering. Blocking JNK activation with a dominant negative mutant of JNK or blocking AP1 activation with a dominant negative mutant of c-jun (TAM67) significantly inhibited PE-induced cell scattering. These data indicate that PE-induced scattering of TFG2 cells is mediated by complex mechanisms, including activation of p42/44 MAPK, p38 MAPK, and JNK. Cell spreading has been reported to play important roles in wound repair, tumor invasion, and metastasis. Therefore, catecholamines acting via the (alpha1)AR may modulate these physiological and pathological processes.

[Recurrence, metastasis and complications of stage I and II endometrial neoplasms treated by different therapeutic modalities]

OBJECTIVE

To make an approach to the relationship between recurrence, metastasis and complication of stage I and II endometrial carcinoma treated by 4 different therapeutic modalities.

METHODS

To compare the rates of recurrence, metastasis and complication in 4 treatment groups (surgery, full-dose preoperative intracavitary irradiation, non-full dose preoperative intracavitary irradiation and radiation alone).

RESULTS

Recurrence and metastasis in surgery, full-dose preoperative intracavitary irradiation, non full-dose preoperative intracavitary and radiotherapy alone groups were 19.8%, 8.1%, 22.2% and 34.6%, respectively. The recurrent rates of vaginal stump were 6.2%, 1.6%, 11.1% and 11.5%, respectively. The rates of proctitis and cystitis in full dose preoperative intracavitary irradiation group were 3.2% and 3.2%, 2.8 and 0.0% in non-full dose preoperative intracavitay irradiation group, and 0.0% and 3.8% in radiotherapy alone group.

CONCLUSIONS

The rates of recurrence and metastasis in full-dose preoperative intracavitary irradiation group were the lowest compared with other groups and incidence of complication was also low. This therapeutic method is the optimal choice for the treatment of endometrial carcinoma with stage I and II.

Neurogenesis and identification of developing layers in the visual cortex of the wallaby (Macropus eugenii)

Birthdates of the neurons that comprise the layers of the mature visual cortex in the wallaby (Macropus eugenii) have been determined with the aid of tritiated thymidine autoradiography. The laminar positions of cells, identified by their birthdates, have then been followed at early stages during development and compared with previously published data on the distribution of thalamocortical afferents and corticothalamic projecting cells (Sheng et al. [1991] J. Comp. Neurol. 307:17-38). Neurons are born in a deep to superficial sequence typical of other mammals. The loosely packed zone of cells, which develops at the base of the thin compact zone of cells at the superficial margin of the cortical plate early in development, was identified as being part of the cortical plate. Afferents did not wait below this zone but grew into the developing cortical layers immediately after the cells that form these layers began accumulating in the loosely packed zone, starting with layer 6 on postnatal day 22 (P22). The genesis of layer 4 did not begin until P32, and these cells reached the superficial cortical plate at P54 and entered the loosely packed zone by P65. Cells of layers 5 and 6 formed the initial projection to the thalamus. Despite the protracted development of the wallaby and the large discrepancy between the time of thalamic ingrowth and genesis of layer 4, there was no extended waiting period for afferents in the subplate.

FIMM, a database of functional molecular immunology

FIMM database (http://sdmc.krdl.org.sg:8080/fimm ) contains data relevant to functional molecular immunology, focusing on cellular immunology. It contains fully referenced data on protein antigens, major histocompatibility complex (MHC) molecules, MHC-associated peptides and relevant disease associations. FIMM has a set of search tools for extraction of information and results are presented as lists or as reports.

[Bcl-2 gene expression in endometrial carcinoma]

OBJECTIVE

To evaluate the relationship between bcl-2 gene and endometrial carcinoma.

METHODS

Immunohistochemical staining was performed on formalin-fixed paraffin-embedded tissue sections. A monoclonal antibody to the bcl-2 gene product was used, the signal was detected using a streptavidin-biotin complex with aminoethylcarbazole. There were 15 cases of endometrial atypical hyperplasia and 50 cases of endometrial carcinoma examined.

RESULTS

Bcl-2 expression was high in endometrial atypical hyperplasia, whereas bcl-2 expression was low in endometrial carcinoma. In endometrial carcinoma, with progression of clinical stage, decreased histologic grade and deepening of cancer invasion, the positive rate of bcl-2 expression was correspondingly decreased.

CONCLUSION

Bcl-2 plays a role in the genesis of endometrial carcinoma especially at the initial stage.

[The clinical evaluation of endometrial carcinoma following irradiation for cervical cancer]

OBJECTIVE

To study the characteristics and clinical features of endometrial carcinoma occurred after pelvic irradiation.

METHODS

Clinical data of 27 cases of endometrial carcinoma occurred after irradiation for cervical cancer were reviewed, estrogen receptor (ER) and progesterone receptor (PR) status were studied in 17 cases by immunohistochemistry.

RESULTS

The incidence of endometrial carcinoma occurred following pelvic irradiation was 0.19%. The mean age of patients was 63 year old. The mean incubation period from pelvic irradiation to diagnosis of the disease was 15.6 years. The proportion of advanced cases was 51.9% (14/27). The expression of ER and PR was very low (11.8%, 2/17). The original sites of 5 cases with stage I were in fundus or corner of the uterus, which received lower dose irradiation formerly. Operation was the best choice of treatment, 19 out of 27 cases received this modality. The survival rate of 3 and 5 year was 56.8%, 37.8%, respectively.

CONCLUSION

The incidence of endometrial carcinoma occurred following pelvic irradiation for cervical cancer was higher than that of cancer occurred spontaneously, the proportion of advanced cases was high, the expression of ER and PR was very low, operation was the mainly method of treatment. The prognosis was poorer than that of spontaneous disease.

[Effects of excessive zinc in fodder on brain development and abilities of learning and memory and their mechanisms in young rats]

OBJECTIVE

To study the effects of excessive zinc in fodder on brain development and abilities of learning and memory and to explore their mechanisms in young rats.

METHODS

Animal models with excessive zinc were established in young Wistar rats during their lactation period. Rats were divided into five groups, Groups ZE1 and ZE2 were fed with excessive zinc, Group AL was freely fed with Flanagna fomula fodder added with zinc sulfate, Group PF was matched pair of Group ZE2 and Group ZE2R was fed with fodder same as Group AL after weaning. Ultrastructure was observed with electron microscopy, their free amino acids, nitrous oxide and somatostatin were measured with neurobiochemical methods, and their abilities to learn and memorize were examined.

RESULTS

Weight of cerebrum and hippocampus in the rats reduced and zinc levels in their serum and hippocampus raised with the increase of zinc content in their fodder. Acute avoidance response (AAR) and movement in the young rats fed with excessive zinc in Groups ZE1 and ZE2 were obviously lower than in Groups AL and PF. AAR was significantly lower in Group ZE2R than that in Groups AL and PF, but significantly higher than that in Group ZE2. There was no significant difference in AAR between Groups PF and AL, but more movement was observed in them. Nitrous oxide in hippocampus raised and somatostatin decreased in Group ZE2, and total amount of excitatory and inhibitory amino acids in brain tissues raised, especially for glutamic acid. Neurones, gliocytes and organella in the CA1 region of hippocampus in the Group ZE2 showed degeneration, necrosis and rupture of synaptic bolus to varied extent.

CONCLUSION

Excessive zinc in fodder could significantly affect brain development and functions in young rats with multiple mechanisms.