Presence of ascites in bullfrog breeders reared and kept on a frog farm / Presença de ascite em reprodutores de rã-touro criados e mantidos em ranário

Ascites is a pathology characterized by the extravasation of fluid from blood vessels and its accumulation in the abdominal cavity, caused by several associated factors. In this paper, we report the occurrence of this syndrome in breeding male and female Bullfrogs fed a commercial fish feed with 40% crude protein. Liver malformation was already observed due to lack of protein deposition in adult animals from the same spawning. The culture of ascitic fluid showed absence of bacterial growth. Kidney histopathology showed, in both sexes, a large number of tubular structures with strongly eosinophilic hyaline material suggesting colloid growth in both the cortical region and spinal cord. The analysis also revealed granulomas in various stages of development, many showing central necrotic material. The kidneys, glomerular, were mostly hypoplastic, with enlarged Bowman space, and many were hyalinized or hemorrhagic; the parenchyma showed dystrophic calcification, and many tubules containing fibrinoid material. The liver displayed a large amount of melanomacrophages in the parenchyma and foci of mono-lymphocytic hepatitis and marked cytoplasmic rarefaction, as well as several hepatocytes with pyknotic nuclei and necrotic cells and dissociation of the hepatic trabeculae. Ascites may be caused by the lesions observed in these organs.(AU)

A ascite é uma condição patológica que se caracteriza pelo extravasamento do líquido dos vasos sanguíneos e por seu acúmulo na cavidade abdominal provocado por uma somatória de fatores. É considerada uma síndrome de caráter multifatorial e, uma vez desencadeado o processo ascítico, esse se torna, na maioria dos casos, irreversível. O objetivo deste trabalho foi relatar a ocorrência dessa síndrome em machos e fêmeas reprodutores de rã-touro (Lithobates catesbeianus), alimentados com ração comercial para peixes, com 40% de proteína bruta, durante três anos e já sendo observada má formação de fígado, por falta de deposição proteica, em animais adultos da mesma desova. A cultura do líquido ascítico demonstrou ausência de crescimento bacteriano. Na histopatologia, observou-se, para ambos os sexos, nos rins, grande número de estruturas tubulares com material fortemente eosinofílico e hialino, sugerindo coloide, tanto na região cortical como na medular. Visualizaram-se também granulomas em vários estágios de desenvolvimento, muitos apresentando material necrótico central. Ainda se pôde observar que os aparelhos renais, os glomérulos, em sua maioria, estavam hipoplásicos e com aumento do espaço de Bowman, e muitos hialinizados ou hemorrágicos; além de calcificação distrófica no parênquima e nos dos túbulos, havia material fibrinoide no seu interior. No fígado, pôde-se ver grande quantidade de melanomacrófagos no parênquima e focos de hepatite monolinfocitária e acentuada rarefação citoplasmática, assim como vários hepatócitos com núcleo em picnose e células em necrose e dissociação das trabéculas hepáticas. A causa da ascite pode ser devido às lesões observadas nesses órgãos.(AU)

Luminescent behavior of Eu3+ doped BaHfO3 perovskite ceramic under UV radiation.

In this paper, luminescent properties of Europium trivalent ion in the matrix with unbalanced charge of barium hafnate under UV radiation, with special emphasis on the 5D0 → 7F0 transition are reported. The synthesis was conducted by the hydrothermal route at 200 °C with a reaction time of 90 min using chlorides as raw materials. In order to determinate the luminescent quenching concentration, the samples were doped with different amounts of Europium trivalent ions being the sample doped with 1 and 3% at of Eu3+ which shows the highest luminescent emission. X-ray diffraction analysis showed that the material crystallize in the cubic perovskite structure with space group Pm-3m. The Energy Dispersive Spectroscopy (EDS) shows there are not elements other those that Ba, Hf, O and Eu in the synthesized material. Photoluminescent emission spectra show peaks of emission associated with the 5D0 → 7FJ (J = 0,1,2,3,4) transitions, characteristics of europium ion. The 5D0 → 7F0 transition centered at 580 nm showed an unusual great intensity when it was excited with the wavelength associated with the charge transfer band (272 nm). Finally the decay time was measured in the 5D0 → 7FJ (J = 0,1,2,3,4) transitions using the sample doped with Eu3+ (3% at).

Synthesis and stimulated luminescence property of Zn(BO2)2:Tb3.

Zinc borate, Zn(BO2)2, doped with different concentrations of terbium (0.5-8mol%) was synthesized and polycrystalline samples were characterized by Scanning Electron Microscopy and X-Ray Diffraction. The Zn(BO2)2 was formed in the pure samples sintered at 750 and 800°C which has the body centered cubic structure, and a ZnB4O7 primitive orthorhombic phase was present. The thermoluminescent intensity was dependents on the thermal treatment (250-500°C) and also on the impurity concentration. The linear dose-response was obtained between 0.022-27.7Gy and 0.5-50Gy when the samples were exposed to beta and gamma radiation, respectively. The complex structure of the glow curves was analyzed by the Computerized Glow Curve Deconvolution method. The kinetics parameters were calculated assuming the general order kinetics model describing accurately the TL process. The glow curves of Tb3+-doped zinc borate phosphor were well deconvolved by six glow peaks. Zinc borate with 8mol% of impurity concentration exhibited an intense radioluminescent emission. The radioluminescent spectra show their maximum bands at 370, 490, 545 and 700nm related to the terbium ion in the zinc borate. These obtained results suggest that the terbium doped zinc borate is a promising phosphor for use in radiation dosimetry because of its high TL sensitivity to the ionizing radiation.

Vitamin C supplementation has no effect on American bullfrog's immune response.

American bullfrog (Lithobates catesbeianus) is the only species raised in Brazilian commercial frog farms, and the intensive culture of these animals has gained great popularity in Brazil over the past several years. Stress is one of the major obstacles in frog culture. To minimise this problem, the aim of the present study was to investigate the role of added vitamin C in the diet of American bullfrogs as an antistress factor through the assessment of plasma corticosterone, leucocyte levels and macrophage activation in animals raised in confinement. The experimental design was entirely randomised, with six treatments (supplementation of 0, 250, 500, 750, 1000 and 2000 mg of vitamin C/kg of feed) and four replications. The plasma corticosterone level, leucocyte level and macrophage activation were evaluated. It was concluded that vitamin C had no influence on the evaluated parameters due to the possible adaptation of the animals to life in captivity (domestication). The results of this research indicate that farmers should not increase the levels of vitamin C in commercial feeds because this would only enhance production costs.

Photo-, cathodo- and thermoluminescent properties of dysprosium-doped HfO2 films deposited by ultrasonic spray pyrolysis.

In this work, the photoluminescent (PL), cathodoluminescent (CL) and thermoluminescent (TL) properties of hafnium oxide films doped with trivalent dysprosium ions are reported. The films were deposited on glass substrates at temperatures ranging from 300 to 600°C, using chlorides as precursor reagents. The surface morphology of films showed a veins shaped microstructure at low deposition temperatures, while at higher temperatures the formation of spherical particles was observed on the surface. X-ray diffraction showed the presence of HfO2 monoclinic phase in the films deposited at temperatures greater than 400°C. The PL and CL spectra of the doped films showed the highest emission band centered at 575nm corresponding to the transitions (4)F9/2→(6)H13/2, which is a characteristic transition of Dy(3+) ion. The greatest emission intensities were observed in samples doped with 1 atomic percent (at%) of DyCl3 in the precursor solution. Regarding the TL behavior, the glow curve of HfO2:Dy(+3) films exhibited spectrum with one broad band centered at about 150°C. The highest intensity TL response was observed on the films deposited at 500°C.

Tracking viral particles in the intestinal contents of the American bullfrog, Lithobates catesbeianus, by Transmission Electron Microscopy / Pesquisa de partículas virais em conteúdo intestinal de rãs-touro americanas, Lithobates catesbeianus, por meio da microscopia eletrônica de transmissão

Feces are an important viral agent elimination route for infected carrier animals and in aquatic organisms these pathogenic agents can very rapidly propagate due to the habitation environment. The objective of this work is to track viral particles in the intestinal contents of bullfrogs (Lithobates catesbeianus) from five commercial frog farms in the region of Vale do Paraíba, in the State of São Paulo, Brazil, using negative contrast transmission electron microscopy (TEM). The Coronaviridae, Paramyxoviridae, Parvoviridae and Herpesviridae families were observed and photographed in specimens. This work emphasizes the importance of adopting sanitary measures in commercial farms and confirms that observing feces by TEM is an efficient and rapid diagnostic tool for detecting viral agents...

Sabendo-se que as fezes são uma importante via de eliminação de agentes virais pelos animais portadores e que, por estarem na água, os agentes patogênicos podem se propagar mais rapidamente, objetivou-se a pesquisa de vírus em conteúdo intestinal de rãs-touro (Lithobates catesbeianus) de cinco ranários comerciais na região do Vale do Paraíba, no estado de São Paulo, pela técnica de microscopia eletrônica de transmissão. As famílias Coronaviridae, Paramixoviridae, Parvoviridae e Herpesviridae foram observadas e fotografadas. Este trabalho ressalta a importância da adoção de medidas sanitárias nas criações, além da confirmação de que a observação de fezes pela microscopia eletrônica de transmissão é uma eficiente ferramenta de diagnóstico rápido para agentes virais...

Thermoluminescent characterization of HfO2:Tb3+ synthesized by hydrothermal route.

Thermo and photoluminescent properties of nanoparticles (NPs) of hafnium oxide (HfO2), both intrinsic and doped with terbium (Tb(3+)) are reported. The NPs of HfO2 were synthesized by hydrothermal route, using hafnium tetrachloride (HfCl4) and terbium chloride hexahydrated (TbCl3∙6H2O) as precursors and sodium hydroxide (NaOH) to adjust the pH. Deionized water was used as solvent in all cases. The synthesis was carried out at different dopant concentrations from 0 to 20 at% of terbium with respect to the amount of hafnium in the precursor solution. The temperature of hydrothermal treatment was 200 °C and 80 min of reaction time. X-ray diffraction results show that at terbium concentrations higher than 15 at% the HfO2 nanoparticles have a crystalline structure corresponding to the tetragonal phase. Thermoluminescent (TL) characterization was performed after 5 min irradiation of the samples with ultraviolet light of 200 nm wavelength. The highest TL emission was observed on samples with 7 at% of Tb, with the TL peak centered at 128 °C. Thermoluminescence analysis shows behavior associated with second-order kinetics with activation energy of 0.49 eV. Photoluminescent spectrum present the characteristics (5)D4→(7)FJ (J=3-6) terbium ion electronic transitions lines centered on 489 nm, 543 nm, 584 nm and 622 nm.

Enrichment of cis-regulatory gene expression SNPs and methylation quantitative trait loci among bipolar disorder susceptibility variants.

We conducted a systematic study of top susceptibility variants from a genome-wide association (GWA) study of bipolar disorder to gain insight into the functional consequences of genetic variation influencing disease risk. We report here the results of experiments to explore the effects of these susceptibility variants on DNA methylation and mRNA expression in human cerebellum samples. Among the top susceptibility variants, we identified an enrichment of cis regulatory loci on mRNA expression (eQTLs), and a significant excess of quantitative trait loci for DNA CpG methylation, hereafter referred to as methylation quantitative trait loci (mQTLs). Bipolar disorder susceptibility variants that cis regulate both cerebellar expression and methylation of the same gene are a very small proportion of bipolar disorder susceptibility variants. This finding suggests that mQTLs and eQTLs provide orthogonal ways of functionally annotating genetic variation within the context of studies of pathophysiology in brain. No lymphocyte mQTL enrichment was found, suggesting that mQTL enrichment was specific to the cerebellum, in contrast to eQTLs. Separately, we found that using mQTL information to restrict the number of single-nucleotide polymorphisms studied enhances our ability to detect a significant association. With this restriction a priori informed by the observed functional enrichment, we identified a significant association (rs12618769, P(bonferroni)<0.05) from two other GWA studies (TGen+GAIN; 2191 cases and 1434 controls) of bipolar disorder, which we replicated in an independent GWA study (WTCCC). Collectively, our findings highlight the importance of integrating functional annotation of genetic variants for gene expression and DNA methylation to advance the biological understanding of bipolar disorder.

Detection of white spot syndrome virus in Brazil using negative staining, immunoelectron microscopy and immunocytochemistry techniques / Detección del virus del síndrome de mancha blanca en el Brasil utilizando inmunomicroscopía e inmunomarcación con partículas de oro coloidal

In this study thirty shrimp samples from commercial marine shrimp (L. vannamei) farms of southern region of Brazil were obtained. Hepatopancreas and shell scrapings fragments collected in these animals were processed by transmission electron microscopy using negative staining (rapid preparation), immunoelectron microscopy and immunocytochemistry (immunolabelling with colloidal gold particles) techniques. On the transmission electron microscopy a great number of white spot virus particles, ovoid or bacilliform-to-ellipsoid, measured 230-290 nm in length and 80-160 nm in diameter with intra-nuclear projections were visualized by the negative staining technique in 27 (90 percent) out of 30 samples examined. Using immunoelectron microscopy technique, the anti-VP 664 serum agllutinated a large number of particles formed by antigen-antibody interaction. In the immunocytochemistry technique, the antigen-antibody reaction was styrongly marked by the particles of colloidal gold over the virus. Notably, this is the first report, to our knowledge, describing use of these microscopy techniques to study Brazilian L. vannamei marine shrimp samples; moreover, this methodology also appears to be a viable complementary tool for diagnosing the presence of the white spot virus within shrimp tissues. Importantly, these are the first photoelectron micrographs of the WSSV in Brazil.

Se obtuvieron para el estudio 30 muestras de camarones marinos comerciales (L. vannamei) de las granjas de la región sur de Brasil. Fueron procesados fragmentos de hepatopáncreas y raspados internos del cefalotórax recogidos en estos animales por microscopía electrónica de transmisión con tinción negativa (preparación rápida), inmunomicroscopía y técnicas de inmunocitoquímica (inmunomarcación con partículas de oro coloidal). En la microscopía electrónica de transmisión de un gran número de partículas de virus de la mancha blanca, ovoide o elipsoidal a baciliformes, medían 230-290 nm de longitud y 80-160 nm de diámetro. En 27 (90 por ciento) de las 30 muestras examinadas intra-nuclear proyecciones se visualizaron mediante la técnica de tinción negativa. Utilizando una técnica de inmunomicroscopía electrónica, el anti-suero VP 664 reunió a un gran número de partículas formadas por la interacción antígeno-anticuerpo. En la técnica de inmunocitoquímica, la reacción antígeno-anticuerpo fue fuertemente reforzada por las partículas de oro coloidal en los virus. En particular, en Brasil este es el primer informe, a nuestro entender, que describe el uso de estas técnicas de microscopía en muestras de camarón marino L. vanamei. Además, esta metodología también parece ser una herramienta complementaria viable para diagnosticar la presencia del virus de la mancha blanca en tejidos de camarón. Es importante destacar que estas son las primeras fotos en microscopia electrónica del WSSV obtenidas en Brasil.

Ethnic disparities in the perception of ethical risks from psychiatric genetic studies.

To examine if ethnic differences in concerns about unfavorable consequences from psychiatric genetic studies, existing between non-Hispanic Black and White populations, persist among participants in an actual genetic study of bipolar disorder. Historically, minority subjects have been less willing to participate in such studies. Participants in the US Bipolar Genome Study (BIGS) were assessed on six items of concerns in the Questionnaire on Genetic Risk (QGR). Each item had five response categories, ranging from "not at all" concerned to "very concerned." Responses from Black (N = 188) and White participants (N = 1,065) formed the base for this analysis. Concerns about unfavorable consequences of conducting psychiatric genetic studies were prevalent in the whole sample. Concern for medical insurance was most prevalent (63.4%), followed by job concern (58.8%) and stigma (57.4%). Racial discrimination was less prevalent (28.1%). Blacks endorsed significantly stronger concerns for all consequences except the medical insurance item (P < 0.008). The most significant ethnic disparity in concerns was for racial discrimination (P < 0.0001). Associations between levels of concern and ethnicity remained significant after adjustments for other factors in multivariate models. Ethnic differences (Blacks vs. Whites) in perceived concerns about unfavorable consequences from participation persist among participants in an actual psychiatric genetic study. This suggests that other factors may play a more critical role in the decision not to participate. Future studies should investigate more comprehensive sources of barriers to consenting for ongoing psychiatric genetic studies in representative samples, incorporating assessments from non-participants as well as participants.

Synthesis and characterization of hafnium oxide films for thermo and photoluminescence applications.

Hafnium oxide (HfO(2)) films were deposited by the ultrasonic spray pyrolysis process. The films were synthesized from hafnium chloride as raw material in deionized water as solvent and were deposited on corning glass substrates at temperatures from 300 to 600 degrees C. For substrate temperatures lower than 400 degrees C the deposited films were amorphous, while for substrate temperatures higher than 450 degrees C, the monoclinic phase of HfO(2) appeared. Scanning electron microscopy showed that the film's surface resulted rough with semi-spherical promontories. The films showed a chemical composition close to HfO(2), with an Hf/O ratio of about 0.5. UV radiation was used in order to achieve the thermoluminescent characterization of the films; the 240 nm wavelength induced the best response. In addition, preliminary photoluminescence spectra, as a function of the deposition temperatures, are shown.

Genome-wide association study of bipolar disorder in European American and African American individuals.

To identify bipolar disorder (BD) genetic susceptibility factors, we conducted two genome-wide association (GWA) studies: one involving a sample of individuals of European ancestry (EA; n=1001 cases; n=1033 controls), and one involving a sample of individuals of African ancestry (AA; n=345 cases; n=670 controls). For the EA sample, single-nucleotide polymorphisms (SNPs) with the strongest statistical evidence for association included rs5907577 in an intergenic region at Xq27.1 (P=1.6 x 10(-6)) and rs10193871 in NAP5 at 2q21.2 (P=9.8 x 10(-6)). For the AA sample, SNPs with the strongest statistical evidence for association included rs2111504 in DPY19L3 at 19q13.11 (P=1.5 x 10(-6)) and rs2769605 in NTRK2 at 9q21.33 (P=4.5 x 10(-5)). We also investigated whether we could provide support for three regions previously associated with BD, and we showed that the ANK3 region replicates in our sample, along with some support for C15Orf53; other evidence implicates BD candidate genes such as SLITRK2. We also tested the hypothesis that BD susceptibility variants exhibit genetic background-dependent effects. SNPs with the strongest statistical evidence for genetic background effects included rs11208285 in ROR1 at 1p31.3 (P=1.4 x 10(-6)), rs4657247 in RGS5 at 1q23.3 (P=4.1 x 10(-6)), and rs7078071 in BTBD16 at 10q26.13 (P=4.5 x 10(-6)). This study is the first to conduct GWA of BD in individuals of AA and suggests that genetic variations that contribute to BD may vary as a function of ancestry.

Singleton deletions throughout the genome increase risk of bipolar disorder.

An overall burden of rare structural genomic variants has not been reported in bipolar disorder (BD), although there have been reports of cases with microduplication and microdeletion. Here, we present a genome-wide copy number variant (CNV) survey of 1001 cases and 1034 controls using the Affymetrix single nucleotide polymorphism (SNP) 6.0 SNP and CNV platform. Singleton deletions (deletions that appear only once in the dataset) more than 100 kb in length are present in 16.2% of BD cases in contrast to 12.3% of controls (permutation P=0.007). This effect was more pronounced for age at onset of mania

Time trends in burdens of cadmium, lead, and mercury in the population of northern Sweden.

The time trends of exposure to heavy metals are not adequately known. This is a worldwide problem with regard to the basis for preventive actions and evaluation of their effects. This study addresses time trends for the three toxic elements cadmium (Cd), mercury (Hg), and lead (Pb). Concentrations in erythrocytes (Ery) were determined in a subsample of the population-based MONICA surveys from 1990, 1994, and 1999 in a total of 600 men and women aged 25-74 years. The study took place in the two northernmost counties in Sweden. To assess the effect of changes in the environment, adjustments were made for life-style factors that are determinants of exposure. Annual decreases of 5-6% were seen for Ery-Pb levels (adjusted for age and changes in alcohol intake) and Ery-Hg levels (adjusted for age and changes in fish intake). Ery-Cd levels (adjusted for age) showed a similar significant decrease in smoking men. It is concluded that for Pb and maybe also Hg the actions against pollution during recent decades have caused a rapid decrease of exposure; for Hg the decreased use of dental amalgam may also have had an influence. For Cd, the decline in Ery-Cd was seen only in smokers, indicating that Cd exposure from tobacco has decreased, while other environmental sources of Cd have not changed significantly. To further improve the health status in Sweden, it is important to decrease the pollution of Cd, and actions against smoking in the community are important.

Understanding and treating depression among cancer patients.

Cancer is a devastating disease. Awareness of this disorder tremendously impacts an individual's life, creating a host of changes to occur. Depression is one concern that many cancer patients experience. It is important to make an accurate and complete assessment of depressive symptoms. Furthermore, a heightened awareness of patients' culture and their perceptions is vital to their assessment, diagnosis, and treatment of depression. In cases of clinical depression, appropriate antidepressants prescribed along with the treatment for cancer are significant for the patient. Palliative counseling for patients and supportive counseling for their family are recommended as part of a treatment plan.

Genetic influences on the retention of inorganic mercury.

Mercury is eliminated as glutathione (GSH) conjugates. GSH production is mediated by glutamyl-cysteine ligase (GCL), and conjugation by glutathione S-transferases (GST). This study tested if polymorphisms in GCL and GST genes modify mercury retention in humans exposed to elemental mercury vapor. Total mercury concentrations in whole blood, plasma and urine, and genotypes for GCLC, GCLM, GSTA1, GSTM1, GSTP1, and GSTT1 were determined in 309 gold miners, gold buyers and controls. The presence of the GCLM-588T allele was associated with increased blood, plasma and urine mercury levels. These results indicate that genotypes with decreased GSH availability for mercury conjugation affect the metabolism of inorganic mercury.

Polymorphisms in glutathione-related genes affect methylmercury retention.

Methylmercury is eliminated from the human body as glutathione (GSH) conjugates. GSH production is mediated by glutamyl-cysteine ligase (GCL) and conjugation by glutathione S-transferases (GST). In this study, the authors tested whether polymorphisms in GCL and GST genes modify methylmercury retention. Erythrocyte mercury concentration (EryHg), plasma polyunsaturated fatty acids (PPUFA), and genotype for GCLC, GCLM, GSTA1, GSTM1, GSTP1, and GSTT1 were determined in 365 individuals. A general linear model was developed for analyzing whether genotype modified the regression of EryHg on PPUFA. The presence of one variant allele for either GCLC-129 or GSTP1-114 was associated with higher EryHg and steeper regression slope. No similar trends were shown for GCLM, GSTA1, GSTM1, or GSTT1. These findings indicate that GCLC polymorphisms that affect GSH production also affect methylmercury retention, and that GSTP1 may play a role in conjugating methylmercury with GSH.

[Fibrolamellar hepatocarcinoma. Case report]. / Hepatocarcinoma fibrolamelar Reporte de un caso.

We reported a case with the hystologic diagnosis of fibromellar carcinoma. A 50 year-old woman without known risk factors for hepatocellular carcinoma. She appeared at the hospital with pain in the upper right quadrant, hepatomeglia and weight loss. The automated enhanced tomography evidenced a heterogeneous tumor with a diameter of 15 cm. compromising segments 4, 5, 6, 7 and 8 of the liver. Tumor calcifications and the retraction of the hepatic capsule were identified. Alpha-fetoprotein levels were normal and a negative serology for viral hepatitis were found. The patient underwent a surgical resection (extended right hepatectomy, the partial resection of the main biliary tract and a portal lymphadenectomy). Six months later she is asymptomatic and evidences no recurrence of the disease. The clinical, pathological, radiological features, treatment options and prognoses of fibrolamellar carcinoma were discussed.

Enhanced expression of p53 and apoptosis induced by blockade of the vacuolar proton ATPase in cardiomyocytes.

Activation of the vacuolar proton ATPase (VPATPase) has been implicated in the prevention of apoptosis in neutrophils and adult cardiac myocytes. To determine the role of the VPATPase in apoptosis of cardiac myocytes, we used a potent and specific inhibitor of the VPATPase, bafilomycin A1. Bafilomycin A1 alone caused increased DNA laddering of genomic DNA and increased nuclear staining for fragmented DNA in neonatal cardiomyocyte apoptosis in a dose- and time-dependent manner. Intracellular acidification in cardiac myocytes was also observed after 18 h of bafilomycin A1 treatment. Accordingly, bafilomycin A1-treated myocytes also showed increased accumulation of p53 protein and p53-dependent transactivation of gene expression, including a persistent upregulation of p21/wild-type p53 activated fragment 1/cyclin kinase inhibitor protein-1 mRNA. The bafilomycin A1-induced increase in p53 protein levels was accompanied by a marked increase in p53 mRNA accumulation. In contrast, cardiac fibroblasts treated with bafilomycin A1 showed no change in p53 protein expression or pHi and did not undergo apoptosis even after 24 h of treatment. Our data suggest that blockade of the VPATPase induces apoptotic cell death of cardiac myocytes and that this may occur through a p53-mediated apoptotic pathway.

p53 and the hypoxia-induced apoptosis of cultured neonatal rat cardiac myocytes.

Myocyte cell loss is a prominent and important pathogenic feature of cardiac ischemia. We have used cultured neonatal rat cardiac myocytes exposed to prolonged hypoxia as an experimental system to identify critical factors involved in cardiomyocyte death. Exposure of myocytes to hypoxia for 48 h resulted in intranucleosomal cleavage of genomic DNA characteristic of apoptosis and was accompanied by increased p53 transactivating activity and protein accumulation. Expression of p21/WAF-1/CIP-1, a well-characterized target of p53 transactivation, also increased in response to hypoxia. Hypoxia did not cause DNA laddering or cell loss in cardiac fibroblasts. To determine whether the increase in p53 expression in myocytes was sufficient to induce apoptosis, normoxic cultures were infected with a replication-defective adenovirus expressing wild-type human p53 (AdCMV.p53). Infected cells expressed high intracellular levels of p53 protein and exhibited the morphological changes and genomic DNA fragmentation characteristic of apoptosis. In contrast, no genomic DNA fragmentation was observed in myocytes infected with the control virus lacking an insert (AdCMV.null) or in cardiac fibroblasts infected with AdCMV.p53. These results suggest that the intracellular signaling pathways activated by p53 might play a critical role in the regulation of hypoxia-induced apoptosis of cardiomyocytes.