Serotonin and catecholaminergic polymorphic ventricular tachycardia: a possible therapeutic role for SSRIs?

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare malignant arrhythmia, usually diagnosed in the adolescent years. The diagnosis can typically be made by one or more of the following: a positive family history, exercise electrocardiography, ambulatory ECG monitoring and/ or an intra-cardiac, electrophysiological examination. This is a case report of a patient with CPVT that was refractory to treatment with beta-blockade and an implanted automatic cardioverter defibrillator. However, after a selective serotonin re-uptake inhibitor (SSRI) was added to the therapeutic regimen, no further episodes of ventricular tachycardia occurred during the following two years.

Enhanced tumor suppression in vitro and in vivo by co-expression of survivin-specific siRNA and wild-type p53 protein

The development of malignant prostate cancer involves multiple genetic alterations. For example, alterations in both survivin and p53 are reported to have crucial roles in prostate cancer progression. However, little is known regarding the interrelationships between p53 and survivin in prostate cancer. Our data demonstrate that the expression of survivin is inversely correlated with that of wtp53 protein (r(s)=0.548) in prostate cancer and in normal prostate tissues. We have developed a therapeutic strategy, in which two antitumor factors, small interfering RNA-survivin and p53 protein, are co-expressed from the same plasmid, and have examined their effects on the growth of PC3, an androgen-independent prostate cancer cell line. When p53 was expressed along with a survivin-specific short hairpin RNA (shRNA), tumor cell proliferation was significantly suppressed and apoptosis occurred. In addition, this combination also abrogated the expression of downstream target molecules such as cyclin-dependent kinase 4 and c-Myc, while enhancing the expression of GRIM19. These changes in gene expression occurred distinctly in the presence of survivin-shRNA/wtp53 compared with control or single treatment groups. Intratumoral injection of the co-expressed construct inhibited the growth and survival of tumor xenografts in a nude mouse model. These studies revealed evidence of an interaction between p53 and survivin proteins plus a complex signaling network operating downstream of the wtp53-survivin pathway that actively controls tumor cell proliferation, survival and apoptosis.

Multimodality imaging of hypoxia in preclinical settings

Hypoxia has long been recognized to influence solid tumor response to therapy. Increasingly, hypoxia has also been implicated in tumor aggressiveness, including growth, development and metastatic potential. Thus, there is a fundamental, as well as a clinical interest, in assessing in situ tumor hypoxia. This review will examine diverse approaches focusing on the preclinical setting, particularly, in rodents. The strategies are inevitably a compromise in terms of sensitivity, precision, temporal and spatial resolution, as well as cost, feasibility, ease and robustness of implementation. We will review capabilities of multiple modalities and examine what makes them particularly suitable for investigating specific aspects of tumor pathophysiology. Current approaches range from nuclear imaging to magnetic resonance and optical, with varying degrees of invasiveness and ability to examine spatial heterogeneity, as well as dynamic response to interventions. Ideally, measurements would be non-invasive, exploiting endogenous reporters to reveal quantitatively local oxygen tension dynamics. A primary focus of this review is magnetic resonance imaging (MRI) based techniques, such as ¹⁹F MRI oximetry, which reveals not only hypoxia in vivo, but more significantly, spatial distribution of pO₂ quantitatively, with a precision relevant to radiobiology. It should be noted that preclinical methods may have very different criteria for acceptance, as compared with potential investigations for prognostic radiology or predictive biomarkers suitable for use in patients.

Identification and characterization of large-effect quantitative trait loci for grain yield under lowland drought stress in rice using bulk-segregant analysis

An F(4:5) population of 490 recombinant inbred lines (RILs) from the cross Apo/(2*)Swarna was used to detect quantitative trait loci (QTL) with large effects on grain yield under drought stress using bulk-segregant analysis (BSA). Swarna is an important rainfed lowland rice variety grown on millions of hectares in Asia, but is highly susceptible to drought and aerobic soil conditions. Apo is an aerobic-adapted variety with moderate tolerance to drought. Two rice microsatellite (RM) markers, RM324, and RM416, located on chromosomes 2 and 3, respectively, were shown via BSA to be strongly associated with yield under lowland drought stress. The effects of these QTL were tested in a total of eight hydrological environments over a period of 3 years. The QTL linked to RM416 (DTY(3.1)) had a large effect on grain yield under severe lowland drought stress, explaining about 31% of genetic variance for the trait (P < 0.0001). It also explained considerable variance for yield under mild stress in lowland conditions and aerobic environments. To our knowledge this is the first reported QTL that has a large effect on yield in both lowland drought and aerobic environments. The QTL linked to RM324 (DTY(2.1)) had a highly significant effect on grain yield in lowland drought stress (R(2) = 13-16%) and in two aerobic trials. The effect of these QTL on grain yield was verified to be not mainly due to phenology differences. Effects of DTY(3.1) on yield under stress have been observed in several other rice mapping populations studied at IRRI. Results of this study indicate that BSA is an effective method of identifying QTL alleles with large effects on rice yield under severe drought stress. The Apo alleles for these large-effect QTL for grain yield under drought and aerobic conditions may be immediately exploited in marker-assisted-breeding to improve the drought tolerance of Swarna.

Conversion from cyclosporin A to sirolimus retards the progression of chronic allograft nephropathy in the long term in a rat kidney transplantation model

In a rat renal allograft model, the long-term effect of conversion from cyclosporin A (CsA) to sirolimus on recipient kidneys and growth factor expression were compared with continuous use or withdrawal of CsA. Kidneys from Fisher 344 rats were orthotopically transplanted into Lewis rats. Four Fisher 344 to Lewis allograft groups were treated post-transplant as follows: (i) CsA (transplant to week 8) then sirolimus (weeks 8 - 24); (ii) CsA (transplant to week 24); (iii) CsA (transplant to week 8) then vehicle (weeks 8 - 24); (iv) control vehicle (transplant to week 24). A fifth group underwent syngeneic isograft (Lewis to Lewis) with no drug treatment. Proteinuria was measured every 4 weeks and grafts harvested at 24 weeks for morphological and immunohistochemical analysis. Conversion from CsA to sirolimus resulted in a significant decrease in proteinuria at 24 weeks, a lower Banff sum score and lower expression of transforming growth factor mRNA compared with continuous use or withdrawal of CsA. In conclusion, conversion from CsA to sirolimus retarded progression of chronic allograft nephropathy in the rat model.

L-arginine reverses cigarette-induced reduction of fractional exhaled nitric oxide in asthmatic smokers

INTRODUCTION

Complex mechanisms regulate nitric oxide (NO) synthesis. Cigarette smoking decreases fractional exhaled NO (FE(NO)), while asthmatic inflammation increases FE(NO). To assess whether the smoking-induced decrease in FE(NO) levels was reversible, asthmatic and non-asthmatic smokers inhaled the NO synthase (NOS) substrate, L-arginine. Aminoguanidine, a relatively selective Type II NOS inhibitor, was used also to assess the role of NOS subtypes in these changes of FE(NO).

METHODS

The study was a single-blinded, placebo-controlled, cross-over design in two parts. Part I: smoking asthmatic and non-asthmatic smoking subjects smoked one cigarette and then inhaled nebulised L-arginine or L-alanine (control). Spirometry, FE(NO), nasal NO (FN(NO)), FE(CO), were measured for 4 h. Part II: subjects inhaled nebulised aminoguanidine prior to an identical protocol as in Part I. Change in FE(NO) was assessed as area under the curve (AUC).

RESULTS

Part I: In asthmatic smokers, cigarette smoking followed by L-arginine caused a significant median increase in AUC of 29.2(17)% FE(NO) change/hour (p = 0.04), which did not occur in non-asthmatic smokers (baseline FE(NO) 12.7(7.1-18) vs. 6.7(4-9.2) ppb, respectively). Part II: Aminoguanidine prior to smoking caused a significant fall in FE(NO) in both asthmatic and non-asthmatic smokers. L-arginine showed significant reversal of this effect in both asthmatic and non-asthmatic subjects.

CONCLUSIONS

In asthmatic smokers, L-arginine increases FE(NO) after cigarette smoking but not in non-asthmatic smokers. The decrease in FE(NO) after aminoguanidine and subsequent partial reversal by L-arginine in both groups, suggests that Type II NOS contributes to the FE(NO) in both.

Alteration products of uraninite from the Colorado Plateau

Uraninite and associated alteration products from the Colorado Plateau were studied by optical microscopy, electron microprobe analysis (EMPA), scanning electron microscopy (SEM) and backscattered electron (BSE) imaging in order to determine the behavior and fate of trace elements, such as Pb, Ca, Si, Th, Zr, and REE, during corrosion under oxidizing conditions. The long-term alteration products and processes of uraninite may provide insight into the corrosion of the UO2in spent nuclear fuel. Uraninite, schoepite, calciouranoite, uranophane, fourmarierite, a Fe-rich uranyl phase, and coffinite were identified. The primary uraninites and alteration phases generally have low trace element contents, except for coffinite from Caribou Mine, Colorado that has Y2O3as high as 0.88 wt%. The highest Zr, Ti, Th and REE values of the uraninite are ThO20.17, Y2O30.28, La2O30.03, Ce2O30.10, Pr2O30.02, Nd2O30.14, Sm2O30.12, Eu2O30.04, Gd2O30.08, ZrO20.93, and TiO20.54 wt%, which are in general lower than the corresponding components in secondary uranyl phases (the highest values are ThO20.21, Y2O30.88, La2O30.05, Ce2O30.15, Pr2O30.05, Nd2O30.18, Sm2O30.14, Eu2O30.11, Gd2O30.08, ZrO22.11, and TiO22.74 wt%), suggesting that trace elements preferentially enter the structures of these secondary uranyl phases (Table 2). A compositional profile of a concentric structure in schoepite shows that, with increasing alteration, UO2, PbO and ZrO2decrease, and SiO2, TiO2, CaO and P2O5increase. Alteration causes loss of U, Pb and Zr and incorporation of Si, Ti, Ca and P into uranyl phases. The Ca-rich calciouranoite from Grants, New Mexico, indicates an interaction between the limestone host rock and uranium minerals. Texturally, concentric structures and micro-fractures are common. Concentric structures are usually composed of both uraninite and uranyl phases, while micro-fractures are common in the secondary phases.

Current status of contraceptive use among rural married women in Anhui Province of China

OBJECTIVES

This study aims to explore the current status of married women in regard of their use of contraceptive methods (permanent methods versus non-permanent methods) and to find out factors that affect the use of contraceptive methods in rural areas of Anhui Province of China.

DESIGN

Survey.

SETTING

Anhui, China.

POPULATION

A total of 53,652 married women aged 18-49 years.

METHODS

A multistage probability sampling method was used to identify a representative sample of 53,652 married women aged 18-49 years. All women were asked to provide detailed information by completing detailed questionnaires.

MAIN OUTCOME MEASURES

Contraceptive prevalence and influence factors.

RESULTS

The total birth control rate of the sample was 95.2%. Samples choosing the permanent and nonpermanent contraceptive methods have taken up 46.7 and 48.5% respectively. Female sterilisation was the first choice with a usage rate of 43.6%, followed by intrauterine device (IUD), which was used by 41.1% of samples. Single-variable analysis showed that the choice of contraceptive methods was associated with age, education level, parity, frequency of sex intercourses in a month, contraceptive knowledge, RTI symptom and the gender of the last child of rural married women.

CONCLUSIONS

A significant increase in contraceptive use of rural married women in Anhui Province of China. Female sterilisation and IUD still play the dominant role. Effective family planning methods should be advocated through adequate counselling on the correct use and proper management, with consideration of the background of custom and belief.

A multicentre study assessing the prevalence of sensitizations in patients with asthma and/or rhinitis in China

BACKGROUND

The prevalence of sensitization in patients with asthma and rhinitis in mainland China remains unclear.

OBJECTIVE

Our aim was to estimate the prevalence of allergy in patients with respiratory allergic diseases such as asthma and/or rhinitis attending respiratory clinics within mainland China. The study also investigated regional and annual differences in the prevalence and pattern of sensitization among the patients in China.

METHOD

A cross-sectional survey was performed in 6304 patients suffering from asthma and/or rhinitis in 17 cities from 4 regions of China. Patients completed a standardized questionnaire asking for the presence of respiratory and allergic symptoms. They also underwent skin prick tests with 13 common aeroallergens.

RESULTS

Among the 6304 patients, 4545 (72.1%) had at least one positive skin prick reaction. The overall prevalence of positive skin prick responses was 59.0% for Dermatophagoides farinae, 57.6% for Dermatophagoides pteronyssinus, 40.7% for Blomia tropicalis, 16.1% for American cockroach, 14.0% for dog, 11.5% for Blatella germanica, 11.3% for Artemisia vulgaris, 10.3% for cat, 6.5% for Ambrosia artemisifolia, 6.3% for mixed mould I, 4.4% for mixed mould IV, 3.5% for mixed grass pollen and 2.2% for mixed tree pollen. Sensitizations to common allergens varied widely between geographical areas and demonstrated unique pattern in patients by stratification with age groups, with asthma and/or rhinitis. Severity of rhinitis and asthma was significantly correlated with skin index of reactivity to Artemisia vulgaris, Ambrosia artemisifolia and to D. pteronyssinus, D. farinae and Blomia tropicalis respectively (P < 0.001). Positive reactivity to the tested allergens and concomitant reactivity to multiple allergens including to house dust mites and Blomia tropicalis was markedly increased in patients with both asthma and rhinitis.

CONCLUSION

House dust mites were the most prevalent allergens in patients with asthma and/or rhinitis in China. There were significant differences in patterns of sensitizations in patients from different geographical areas, age groups as well as asthma and/or rhinitis.

The Sino-MONICA-Beijing Study: report on results between 1984 and 1986

The Beijing Heart Lung and Blood Vessel Medical Center has participated in the World Health Organisation MONICA project since 1981. Our study, named Sino-MONICA-Beijing, has been carried out in Beijing and covers a population approximately of 700,000. After a 2-year pilot study, the project started formally January 1, 1984. This paper presents the organization and methodology of the study, with emphasis on the monitoring system and on how events were found. The main results of the cardiovascular disease (CVD) event monitoring are as follows: average annual mortality from all causes, for the 3-year period of 1984-86 was 319/100,000 for men and 238/100,000 for women aged 25-64; from CVD 119/100,000 for men and 101/100,000 for women; from ischemic heart disease 29/100,000 for men and 14/100,000 for women; and from cerebrovascular disease 59/100,000 for men and 52/100,000 for women. Preliminary experience has shown that Sino-MONICA-Beijing is a well-standardized project of long-term surveillance of CVD in the communities of Beijing.

The H19 gene imprinting in normal pregnancy and pre-eclampsia

OBJECTIVES

To characterize the H19 gene imprinting in the placental tissues of normal pregnancy and pre-eclampsia.

METHODS

A total of 188 subjects at 5-9 weeks, 54 at 10-12 weeks, 50 at the second trimester, 65 at term of gestation, and 30 with pre-eclampsia at the third trimester were recruited. Their DNA and RNA were extracted from the placental tissues. The H19 genotypes for individuals were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and the H19 gene imprinting was identified by reverse transcription-PCR (RT-PCR) and the RsaI-based RFLP. The levels of H19 RNA transcripts in the pre-eclampsia patients with the H19 heterozygote were measured by quantitative RT-PCR. The frequency of the H19 heterozygote, the H19 imprinting status among different trimesters of pregnancy and the clinical symptoms in the pre-eclampsia patients were analyzed.

RESULTS

(1) About 40-46% of subjects at varying stages of normal pregnancy showed the H19 heterozygote, and 24 out of 87 (27.59%) heterozygous cases were at 5-9 weeks of gestation, but no single one in other stages displayed biallelic expression of the H19 gene. (2) Thirteen out of 30 pre-eclampsia patients were H19 heterozygous and six of these showed the biallelic expression of the H19 gene (loss of imprinting). (3) The pre-eclampsia patients with the biallelic expression of H19 tended to have severer hypertension although their H19 RNA transcription level was similar to that in those with monoallelic expression.

CONCLUSIONS

(1) The biallelic expression of the H19 gene exists in some cases at the early stage of normal pregnancy and changes into monoallelic expression near 10 weeks of gestation. The dynamic alternations in the patterns of the H19 gene imprinting may regulate the maintenance of normal pregnancy. (2) The loss of the H19 gene imprinting in the placental tissues of pre-eclampsia patients may be associated with severe hypertension, contributing to the pathogenic process of pre-eclampsia.

Neural stem cell tropism to glioma: critical role of tumor hypoxia

Hypoxia is a critical aspect of the microenvironment in glioma and generally signifies unfavorable clinical outcome. Effective targeting of hypoxic areas in gliomas remains a significant therapeutic challenge. New therapeutic platforms using neural stem cells (NSC) for tumor-targeted drug delivery show promise in treatment of cancers that are refractory to traditional therapies. However, the molecular mechanisms of NSC targeting to hypoxic tumor areas are not well understood. Therefore, we investigated the role of hypoxia in directed migration of NSCs to glioma and identified the specific signaling molecules involved. Our data showed that hypoxia caused increased migration of human HB1.F3 NSCs to U251 human glioma-conditioned medium in vitro. In HB1.F3 NSCs, hypoxia led to up-regulation of CXCR4, urokinase-type plasminogen activator receptor (uPAR), vascular endothelial growth factor receptor 2 (VEGFR2), and c-Met receptors. Function-inhibiting antibodies to these receptors inhibited the migration of HB1.F3 cells to glioma-conditioned medium. Small interfering RNA knockdown of hypoxia-inducible factor-1alpha in glioma cells blocked the hypoxia-induced migration of NSCs, which was due to decreased expression of stromal cell-derived factor-1 (SDF-1), uPA, and VEGF in glioma cells. Our in vivo data provided direct evidence that NSCs preferentially distributed to hypoxic areas inside intracranial glioma xenografts, as detected by pimonidazole hypoxia probe, as well as to the tumor edge, and that both areas displayed high SDF-1 expression. These observations indicate that hypoxia is a key factor in determining NSC tropism to glioma and that SDF-1/CXCR4, uPA/uPAR, VEGF/VEGFR2, and hepatocyte growth factor/c-Met signaling pathways mediate increased NSC-to-glioma tropism under hypoxia. These results have significant implications for development of stem cell-mediated tumor-selective gene therapies.

Effects of PI3-k/Akt short hairpin RNA on proliferation, fibronectin production and synthesis of thrombospondin-1 and transforming growth factor-beta1 in glomerular mesangial cells induced by sublytic C5b-9 complexes

OBJECTIVES

To explore proliferation of glomerular mesangial cells (GMC) and secretion of extracellular matrix (fibronectin induced by sublytic C5b-9 complexes), and then ascertain the role of phosphatidylinositol 3-kinase (PI3-k)/Akt signal pathway in these processes, by using small hairpin RNAs.

MATERIAL AND METHODS

The expression of cyclin D(2), (3)H-thymidine into DNA and production of fibronectin including thrombospondin-1 and transforming growth factor-beta(1) in the GMCs stimulated by sublytic C5b-9 or transfected with expression vectors of PI3-k and Akt short hairpin RNA or LY294002 (PI3-k inhibitor) were measured by Real-time quantitative polymerase chain reaction (PCR), Western blot, enzyme-linked immunosorbent assay (ELISA) and (3)H-thymidine incorporation ((3)H-TdR), respectively.

RESULTS

The expression of cyclin D(2), (3)H-thymidine into DNA and fibronectin in the GMCs stimulated by sublytic C5b-9 could all be increased, and the elevations of these parameters mentioned above were also markedly reduced in the GMCs transfected with vectors of PI3-k and Akt short hairpin RNA or LY294002, respectively.

CONCLUSIONS

These data indicate that sublytic C5b-9 can promote proliferation of GMCs and secretion of fibronectin as well as synthesis of thrombospondin-1 and transforming growth factor-beta(1). The PI3-k/Akt signal pathway in these reactions, mediated by sublytic C5b-9 complexes, may play at least a partial role.