Regulation of PUMA-alpha by p53 in cisplatin-induced renal cell apoptosis

Nephrotoxicity is a major side effect of cisplatin, a widely used cancer therapy drug. Depending on its concentration, cisplatin induces necrosis or apoptosis of tubular cells in the kidneys, whereas the underlying injury mechanism is unclear. Our recent work has suggested a critical role for p53 in cisplatin-induced tubular cell apoptosis; nevertheless, the apoptotic events triggered by p53 remain elusive. The current study has examined Bcl-2 family proteins, critical regulators of apoptosis that may be subjected to p53 regulation. Following cisplatin treatment, the expression of Bcl-xL, an antiapoptotic molecule, was suppressed, while the expression of Bak, a proapoptotic molecule, increased slightly. Of interest, PUMA-alpha, a newly identified p53-responsive proapoptotic Bcl-2 family protein, was drastically induced by cisplatin. PUMA-alpha induction preceded or paralleled the development of apoptosis. Induced PUMA-alpha was localized in mitochondria and appeared to antagonize Bcl-xL via molecular interaction. PUMA-alpha induction during cisplatin treatment was attenuated by pifithrin-alpha, a pharmacological inhibitor of p53, which was accompanied by the amelioration of Bax activation, cytochrome c release and apoptosis. Moreover, PUMA-alpha induction was suppressed by dominant-negative p53. Importantly, cisplatin-induced apoptosis was ameliorated in PUMA-alpha knockout cells. In vivo, cisplatin induced PUMA-alpha in the kidneys, and the inductive response was abrogated in p53-deficient animals. Together, this study has demonstrated the first compelling evidence for the involvement of PUMA-alpha in p53-mediated renal cell apoptosis during cisplatin nephrotoxicity.

Electrodynamic heart model construction and ECG simulation

OBJECTIVES

In this paper, we present a unified electrodynamic heart model that permits simulations of the body surface potentials generated by the heart in motion. The inclusion of motion in the heart model significantly improves the accuracy of the simulated body surface potentials and therefore also the 12-lead ECG.

METHODS

The key step is to construct an electromechanical heart model. The cardiac excitation propagation is simulated by an electrical heart model, and the resulting cardiac active forces are used to calculate the ventricular wall motion based on a mechanical model. The source-field point relative position changes during heart systole and diastole. These can be obtained, and then used to calculate body surface ECG based on the electrical heart-torso model.

RESULTS

An electromechanical biventricular heart model is constructed and a standard 12-lead ECG is simulated. Compared with a simulated ECG based on the static electrical heart model, the simulated ECG based on the dynamic heart model is more accordant with a clinically recorded ECG, especially for the ST segment and T wave of a V1-V6 lead ECG. For slight-degree myocardial ischemia ECG simulation, the ST segment and T wave changes can be observed from the simulated ECG based on a dynamic heart model, while the ST segment and T wave of simulated ECG based on a static heart model is almost unchanged when compared with a normal ECG.

CONCLUSIONS

This study confirms the importance of the mechanical factor in the ECG simulation. The dynamic heart model could provide more accurate ECG simulation, especially for myocardial ischemia or infarction simulation, since the main ECG changes occur at the ST segment and T wave, which correspond with cardiac systole and diastole phases.

A common polymorphism in the 3'UTR of cyclooxygenase 2/prostaglandin synthase 2 gene and risk of lung cancer in a Chinese population

Cyclooxygenases (COXs) are key enzymes that convert arachidonic acid to prostaglandins. Overexpression of COX-2, one of the COX isozymes, has been shown to be an early event in lung carcinogenesis and may play an important role in lung cancer development. A common single nucleotide polymorphism, T8473C, located within a potential functional region in the 3'UTR of COX-2 gene was identified and we hypothesized that this COX-2 variant is associated with lung cancer risk. To test this hypothesis, we genotyped this variant in a case-control study of 322 histologically-confirmed lung cancer patients and 323 age and sex frequency-matched cancer-free controls in a Chinese population. The results showed that the frequencies of variant genotypes 8473CT/CC were significantly less common in the cases (27.3%) than in the controls (35.3%) (P=0.034), suggesting that the 8473C allele was protective against lung cancer. Multivariate logistic regression analyses revealed that the COX-2 variant genotypes (8473CT/CC) were associated with a significantly decreased risk of lung cancer compared with the 8473TT wild-type homozygotes (OR=0.64, 95% CI=0.45-0.92). When we defined the reference group as non-smokers having the 8473CT/CC variant genotypes, the smokers with the 8473TT wild-type genotype had the greatest risk (adjusted OR=5.28, 95% CI=3.10-9.00). These findings indicate that the COX-2 T8473C polymorphism may contribute to lung cancer susceptibility in the Chinese population. Further larger molecular epidemiological studies are warranted to confirm these findings.

Safety of mycophenolate mofetil versus azathioprine in renal transplantation: a systematic review

INTRODUCTION

To evaluate the safety of mycophenolate mofetil (MMF) versus azathioprine (Aza) in renal transplantation, we compared their side effects using evidence-based methods.

METHODS

Medline, Embase, Cochrane library, and Chinese Biomedicine database (CBM) were searched to select randomized clinical trials that had one group using MMF and another group using Aza as an immunosuppressive drugs. Safety analysis consist of the following factors: diarrhea, abdominal pain, vomiting, nausea, constipation, CMV infection, leukopenia, anemia, thrombocytopenia or skin malignancy. RevMan 4.11 software was used for the systematic review analysis.

RESULT

Twenty trials including 6387 patients were identified. The diarrhea incidence with MMF (3 g/d) was higher than for Aza at 1 and 3 years (P < .05). Diarrhea on MMF (2 g/d) was higher than for Aza within 6 months (P < .05). CMV infection incidence on MMF (3 g/d) was higher than for Aza's at 3 years (P < .05), but MMF (2 g/d) did not show a statistical significance compared with Aza. Leukopenia incidence on MMF (3 g/d) was higher than that on Aza, whereas the incidence with MMF (2 g/d) was not significantly different from Aza. Skin malignancy incidence showed no statistical difference between MMF 3 g/d, MMF 2 g/d, or Aza.

CONCLUSION

The use of MMF is associated with slight increases in gastrointestinal adverse effects, some hematologic adverse events, and CMV infections compared with Aza. Larger sample sizes of randomized controlled trials are needed to evaluate the safety of MMF.

An object-oriented designed finite-difference time-domain simulator for electromagnetic analysis and design in MRI--applications to high field analyses

This paper presents a finite-difference time-domain (FDTD) simulator for electromagnetic analysis and design applications in MRI. It is intended to be a complete FDTD model of an MRI system including all RF and low-frequency field generating units and electrical models of the patient. The program has been constructed in an object-oriented framework. The design procedure is detailed and the numerical solver has been verified against analytical solutions for simple cases and also applied to various field calculation problems. In particular, the simulator is demonstrated for inverse RF coil design, optimized source profile generation, and parallel imaging in high-frequency situations. The examples show new developments enabled by the simulator and demonstrate that the proposed FDTD framework can be used to analyze large-scale computational electromagnetic problems in modern MRI engineering.

Study of hepatic function matching between banna minipig inbred and humans

As a unique inbred pig Banna minipig inbred (BMI) is potentially suitable for pig-to-human xenotransplantation due to its clear genetic background and minor interindividual differences. Previous studies of BMI have focused on immunological barriers between BMI and humans. However, a comparison of liver function between donor animals and humans is an essential premise for successful xenotransplantation. In this study, we investigated routine hepatic functions, protein electrophoresis, and drug metabolism to compare capacity of liver synthesis, metabolism, and drainage between BMI and humans. The results showed no significant differences in the concentrations of albumin and globulin synthesized in the liver (alpha1, alpha2, and beta-globulin). Serum enzyme activities in BMI were higher than those in humans, and levels of total bilirubin and direct-reacting bilirubin of BMI were lower than those of humans. In BMI, the clearance of antipyrine, a widely used model drug to study hepatic drug metabolism, was 16 times greater than that by humans, with a mean residual time of antipyrine in BMI, one-tenth of that in human. These findings suggested that BMI livers are similar to humans in albumin and alpha, beta-globulin synthesis, but stronger in bilirubin elimination, enzyme activity, and drug metabolism. BMI livers may have stronger functions compared with those of humans. No incompatibility was identified in hepatic function between BMI and humans.

DNA repair gene XPD polymorphism and lung cancer risk: a meta-analysis

Interindividual variation in lung cancer susceptibility may be modulated in part through genetic polymorphisms in the DNA repair genes, especially the genes involved in the nucleotide excision repair (NER) pathway. The xeroderma pigmentosum complementary group D (XPD) is one of the NER genes, and two of the XPD polymorphisms 751A --> C and 312G --> A have been extensively studied in the association with lung cancer, although published studies have been inconclusive. To clarify the impact of XPD polymorphisms on lung cancer risk, we performed a meta-analysis of the published data from nine (10 comparisons) individual case-control studies of 3725 lung cancer cases and 4152 controls. The results showed that individuals with the XPD 751CC genotype had a 21% (odds ratio (OR)= 1.21, 95% confidence interval (CI) = 1.02-1.43) increased risk of lung cancer compared with individuals with the 751AA genotype without any between-study heterogeneity (P = 0.26). There was also a significant association in the recessive model of 751 C allele by comparing the CC with AC + AA genotypes (OR = 1.19, 95% CI = 1.02-1.40). The results also showed a significantly increased risk of lung cancer associated with the 312AA homozygous genotype compared with the GG genotype and the 312 A allele in the recessive model (compared with GA + AA genotypes) (OR = 1.27, 95% CI = 1.04-1.56 and OR = 1.32, 95% CI = 1.09-1.59, respectively). These results support the hypothesis that both the XPD 751 C and 312 A are risk alleles and individuals with the XPD 751 CC and 312 AA genotypes are at higher risk of developing lung cancer. Large multi-center studies with precise design, and stratified/adjusted analyses of the gene-gene (haplotypes) and gene-environment interactions are needed.

Study of renal function matching between banna minipig inbred line and human

Pigs have been thought to be ideal candidates for xenotransplant donors. However besides the immunological barrier, physiological and pharmacokinetic comparabilities of kidney function between donor animals and humans are important factors for successful xenotransplantation. As a unique large inbred animal, Banna Minipig Inbred (BMI) has been reported to be a potential large animal suitable for xenotransplantation. However, its physical and pharmacokinetic compatibilities with humans have not been documented. The purpose of this investigation was to measure renal routine function, glomerular filtration rate (GFR), renal blood flow (ERPF), and drug metabolism to evaluate comparability to humans. The results suggested that the renal function of BMI was similar to that of humans to eliminate nonprotein nitrogenous end products of metabolism. Pharmacokinetics of p-aminohippurate (PAH) and inulin--the most widely used methods to assess ERPF and GFR--showed that BMI showed lower values than humans for GFR, but similar function to humans in ERPF. The pharmacokinetics of cefazolin; a widely used model drug to study kidney drug metabolizing capacity, showed greater overall renal drug elimination of BMI than of humans. These results suggested that BMI did show comparable data to human renal function.

Efficient preparation of L-cysteic acid and its esters

L-Cysteic acid and its esters were prepared in good yields from the oxidation of L-cystine by chlorine in water and in alcohols. When the reaction was carried out in alcohols the corresponding esters were produced.

Efficacy of mycophenolate mofetil versus azathioprine after renal transplantation: A systematic review

INTRODUCTION

Our objective was to evaluate the efficacy of mycophenolate acid (MMF) versus azathioprine (AZA) after renal transplantation.

MATERIALS AND METHODS

The following electronic databases were searched: Medline, Embase, Cochrane library, and Chinese Biomedicine database (CBM). Randomized controlled trials (RCTs) were subjected to Revman 4.11 for statistical analyses.

RESULTS

Twenty-three RCTs were identified to compare MMF and AZA for antirejection, prophylaxis after renal transplantation. The data showed that MMF (2 g/d) was more beneficial than AZA to improve graft and long-term patient survivals, but there was no statistical differences between MMF (3 g/d) and AZA. Whether at 6 months or at 1 year after renal transplantation, the use of MMF (2 g/d) or MMF (3 g/d) markedly reduced the incidence of biopsy-proven rejection.

CONCLUSION

Compared with AZA, MMF is a more potent immunosuppressive drug, that is more efficient in reducing the incidence of acute rejection episodes after renal transplantation. MMF can improve the graft and patient survival rate. The 2 g per day dosage is more acceptable.

[Significance of human telomerase RNA expression in situ in malignant melanoma]

By using the method of hybridization in situ, human telomerase RNA(hTR) are detected in 36 cases of malignant melanoma tissue, 16 cases of nevocellular nevus and 12 cases of normal skin. Results showed that the positive expression percentage of hTR in malignant melanoma, nevocellular nevus and normal skin was 86.3%, 6.26% and 12.7%, respectively. The positive expression percentage of hTR in malignant melanoma was significantly higher than that of nevocellular nevus and normal skin(P < 0.01). Meanwhile, the positive expression intensity of hTR in metastatic malignant melanoma is frequently stronger than that of original malignant melanoma(P < 0.05). The results suggest that hTR might indirectly reflect the telomerase activity, and be used as a new marker for diagnosis of malignant melanoma and metastasis prediction.

Human babesiosis in Japan: epizootiologic survey of rodent reservoir and isolation of new type of Babesia microti-like parasite

We have carried out epizootiologic surveys at various sites in Japan to investigate wild animals that serve as reservoirs for the agents of human babesiosis in the country. Small mammals comprising six species, Apodemus speciosus, Apodemus argenteus, Clethrionomys rufocanus, Eothenomys smithii, Crocidura dsinezumi, and Sorex unguiculatus, were trapped at various places, including Hokkaido, Chiba, Shiga, Hyogo, Shimane, and Tokushima Prefectures. Animals harboring Babesia microti-like parasites were detected in all six prefectures. Inoculation of their blood samples into hamsters gave rise to a total of 20 parasite isolates; 19 were from A. speciosus, and the other 1 was from C. rufocanus. Sequencing of the parasite small-subunit rRNA gene (rDNA) sequence revealed that 2 of the 20 isolates were classified as Kobe type because their rDNAs were identical to that of the Kobe strain (the strain from the Japanese index case). The other 18 isolates were classified as a new type, designated the Hobetsu type, because they all shared an identical rDNA sequence which differed significantly from both that of Kobe-type isolates and that of northeastern United States B. microti (U.S. type). The parasites with Kobe-, Hobetsu- and U.S.-type rDNAs were phylogenetically closely related to each other but clearly different from each other antigenically. The isolates from rodents were demonstrated to be infective for human erythrocytes by inoculation into SCID mice whose erythrocytes had been replaced with human erythrocytes. The results suggest that a new type of B. microti-like parasite, namely, the Hobetsu type, is the major one which is prevalent among Japanese wild rodents, that A. speciosus serves as a major reservoir for both Kobe- and Hobetsu-type B. microti-like parasites, and that C. rufocanus may also be an additional reservoir on Hokkaido Island.

Sensitivity to benzo(a)pyrene diol-epoxide associated with risk of breast cancer in young women and modulation by glutathione S-transferase polymorphisms: a case-control study

Mounting epidemiological evidence suggests that smoking may play a role in the etiology of breast cancer. Because smoking-related DNA adducts are detectable in both normal and malignant breast tissues, we hypothesized that breast cancer patients may be sensitive to tobacco-induced carcinogenesis, and this sensitivity could be modulated by variants of metabolic genes. To test this hypothesis, we evaluated benzo(a)pyrene diol-epoxide (BPDE)-induced mutagen sensitivity and polymorphisms of GSTM1 and GSTT1 in a pilot case-control study of breast cancer. Short-term cell cultures were established from blood samples of 100 female breast cancer patients and 105 healthy controls. After 5 h of in vitro exposure to 4 microM of BPDE, we harvested the lymphocytes for cytogenetic evaluation and recorded and compared the frequency of BPDE-induced chromatid breaks between cases and controls. We used a multiplex PCR-based assay to simultaneously detect polymorphisms of GSTM1 and GSTT1 from genomic DNA. We performed univariate and multivariate logistic regression analyses and calculated odds ratios (OR) and 95% confidence intervals (CIs). Cases had a significantly higher frequency of chromatid breaks than did controls (P < 0.0001). The level of chromatid breaks greater than the median value of controls was associated with a >3-fold increased risk of breast cancer [adjusted odds ratio (ORadj) = 3.11; 95% CI = 1.72-5.64]. The risk was more pronounced in those who were < 45 years (ORadj = 4.79; 95% CI = 1.87-12.3), ever-smokers (ORadj = 5.55; 95% CI = 1.85-16.6), alcohol drinkers (ORadj = 4.64; 95% CI = 1.70-12.7), and those who had the GSTT1 null variant (ORadj = 8.01; 95% CI = 1.16-55.3). These data suggest that sensitivity to BPDE-induced chromosomal aberrations may contribute to the risk of developing breast cancer, and such sensitivity may be modulated by both genetic and environmental factors. Larger studies are needed to confirm our findings.

Polymorphic hCHK2/hCds1 codon 84 allele and risk of squamous cell carcinoma of the head and neck--a case-control analysis

Checkpoint kinase 2 (hCHK2/hCds1) is a tumor suppressor gene involved in cell-cycle control. A hCHK2/hCds1 polymorphism in codon 84 (A-->G at nucleotide 252) was recently identified in Li-Fraumeni syndrome patients. Because cell cycle regulates DNA repair that is associated with cancer risk, we hypothesized that this new polymorphism exists in the general population and is associated with cancer risk. To test this hypothesis, we evaluated the role of this polymorphism in a case-control study of 215 non-Hispanic white patients with newly diagnosed squamous cell carcinoma of the head and neck (SCCHN) and 229 frequency-matched cancer-free controls. We found that the hCHK2/hCds1 codon 84 variant was rare and less frequent in non-Hispanic white cases (0.0186) than in controls (0.0437; P = 0.033). Although no variant homozygotes were detected in these cases and controls, heterozygosity protected against SCCHN, representing a 60% reduction of risk (adjusted odds ratio = 0.40; 95% confidence intervals, 0.17-0.93) compared with wild-type homozygotes. The variant allele was also rare in other ethnic groups (0.0487, 0.0095 and 0.0541 in 115 African Americans, 105 Hispanic Americans and 111 native Chinese, respectively), and only one variant homozygous individual (a Chinese subject) was identified. These results suggest that this hCHK2/hCds1 codon 84 polymorphism is rare and may have a protective role in the aetiology of SCCHN in non-Hispanic whites. Larger studies are warranted to confirm this finding and further mechanistic studies are needed to understand biological relevance of this polymorphism.

Determination of Danshensu, a major active compound of Radix Salvia miltiorrhiza in dog plasma by HPLC with fluorescence detection

A simple and sensitive high performance liquid chromatography method has been developed for the determination of Danshensu (3, 4-dihydroxyphenyllactic acid) in dog plasma. Plasma samples were extracted with ethyl acetate. Analysis of the extracts was performed on a reversed-phase column with an aqueous phosphate buffer-acetonitrile (93:7, v/v) mobile phase, and 4-hydroxybenzoic acid was used as the internal standard. Fluorescence detection at 285 nm (excitation) and 320 nm (emission) was employed. Standard curves were linear in the range from 0.125 to 11.3 microg/mL (regression coefficient r > 0.993) on three different days. Mean recovery was determined as 96.4% by analysis of plasma standard containing 0.63, 5.65 and 11.3 microg/mL of Danshensu. The inter-day precision (RSD) ranged from 3.4 to 8.6% at concentrations of 0.125, 1.88, 6.28 and 11.3 microg/mL, and the intra-day precision was better than 7.2%. The detection and quantitation limits were 0.063 and 0.125 microg/mL, respectively. This validated assay was applied to the determination of Danshensu concentration in dog plasma after oral administration of Radix Salvia miltiorrhiza extracts.

Selection of genetically modified chicken blastodermal cells by magnetic-activated cell sorting

The use of chicken blastodermal cells (CBC) in the production of transgenic chickens requires incorporation of the desired stable genetic modification into CBC. With greater proportions of stably transfected blastodermal cells in the embryo inoculum, the frequency of intermediate chimeric birds is greater. Magnetic-activated cell sorting (MACS) was evaluated as a method for enrichment of transfected CBC. This approach requires surface expression of a molecule that can be recognized by an antibody. Chicken blastodermal cells from fertilized Barred Plymouth Rock eggs were coelectroporated with pmiwZ and pMACS Kk and were sorted magnetically by expression of the mouse H-2Kk molecule on the surface of successfully transfected cells. The effectiveness of sorting was assessed using X-gal staining to detect lacZ expression from the pmiwZ plasmid. After 48 h of culture, lacZ-positive cells appeared to be enriched 1.4-fold in the MACS selected population. Cells from this enriched pool contributed to extra-embryonic and intra-embryonic tissues of 72-h White Leghorn recipient embryos with a marginal increase in levels of intra-embryonic contribution. Our demonstration that transfected, cultured, and magnetically sorted CBC maintain their ability to contribute to ectodermal and mesodermal lineages of intra-embryonic tissues illustrates the potential value of this technique for introducing genetic modifications into birds.

RNAi as random degradative PCR: siRNA primers convert mRNA into dsRNAs that are degraded to generate new siRNAs

In posttranscriptional gene silencing (PTGS), "quelling," and RNA interference (RNAi), 21-25 nucleotide RNA fragments are produced from the initiating dsRNA. These short interfering RNAs (siRNAs) mediate RNAi by an unknown mechanism. Here, we show that GFP and Pp-Luc siRNAs, isolated from a protein complex in Drosophila embryo extract, target mRNA degradation in vitro. Most importantly, these siRNAs, as well as a synthetic 21-nucleotide duplex GFP siRNA, serve as primers to transform the target mRNA into dsRNA. The nascent dsRNA is degraded to eliminate the incorporated target mRNA while generating new siRNAs in a cycle of dsRNA synthesis and degradation. Evidence is presented that mRNA-dependent siRNA incorporation to form dsRNA is carried out by an RNA-dependent RNA polymerase activity (RdRP).

Gamma-radiation sensitivity and risk of glioma

BACKGROUND

About 9% of human cancers are brain tumors, of which 90% are gliomas. gamma-Radiation has been identified as a risk factor for brain tumors. In a previous pilot study, we found that lymphocytes from patients with glioma were more sensitive to gamma-radiation than were lymphocytes from matched control subjects. In this larger case-control study, we compared the gamma-radiation sensitivity of lymphocytes from glioma patients with those from control subjects and investigated the association between mutagen sensitivity and the risk for developing glioma.

METHODS

We used a mutagen sensitivity assay (an indirect measure of DNA repair activity) to assess chromosomal damage. We gamma-irradiated (1.5 Gy) short-term lymphocyte cultures from 219 case patients with glioma and from 238 healthy control subjects frequency matched by age and sex. After irradiation, cells were cultured for 4 hours, and then Colcemid was added for 1 hour to arrest cells in mitosis. Fifty metaphases were randomly selected for each sample and scored for chromatid breaks. All statistical tests were two-sided.

RESULTS

We observed a statistically significantly higher frequency of chromatid breaks per cell from case patients with glioma (mean = 0.55; 95% confidence interval [CI] = 0.50 to 0.59) than from control subjects (mean = 0.44; 95% CI = 0.41 to 0.48) (P<.001). Using 0.40 (the median number of chromatid breaks per cell in control subjects) as the cut point for defining mutagen sensitivity and adjusting for age, sex, and smoking status, we found that mutagen sensitivity was statistically significantly associated with an increased risk for glioma (odds ratio = 2.09; 95% CI = 1.43 to 3.06). When the data were divided into tertiles, the relative risk for glioma increased from the lowest tertile to the highest tertile (trend test, P<.001).

CONCLUSION

gamma-Radiation-induced mutagen sensitivity of lymphocytes may be associated with an increased risk for glioma, a result that supports our earlier preliminary findings.