Catalytic properties of Na(+)-translocating V-ATPase in Enterococcus hirae

V-ATPases make up a family of proton pumps distributed widely from bacteria to higher organisms. We found a variant of this family, a Na(+)-translocating ATPase, in a Gram-positive bacterium, Enterococcus hirae. The Na(+)-ATPase was encoded by nine ntp genes from F to D in an ntp operon (ntpFIKECGABDHJ): the ntpJ gene encoded a K(+) transporter independent of the Na(+)-ATPase. Expression of this operon, encoding two transport systems for Na(+) and K(+) ions, was regulated at the transcriptional level by intracellular Na(+) as the signal. Structural aspects and catalytic properties of purified Na(+)-ATPase closely resembled those of other V-type H(+)-ATPases. Interestingly, the E. hirae enzyme showed a very high affinity for Na(+) at catalytic reaction. This property enabled the measurement of ion binding to this ATPase for the first time in the study of V- and F-ATPases. Properties of Na(+) binding to V-ATPase were consistent with the model that V-ATPase proteolipids form a rotor ring consisting of hexamers, each having one cation binding site. We propose here a structure model of Na(+) binding sites of the enzyme.

Fission yeast homologues of the B' subunit of protein phosphatase 2A: multiple roles in mitotic cell division and functional interaction with calcineurin

BACKGROUND

Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase distributed in eukaryotes from yeast to human, and plays pivotal roles in diverse cellular functions such as metabolism, cell cycle progression, gene expression and development. PP2A holoenzyme is a heterodimer of a catalytic subunit C and a regulatory subunit A, or a heterotrimer of C, A and a variable regulatory subunit consisting of three families; B, B', and PR72. Specific functions for each variable subunit are not well understood.

RESULTS

Two fission yeast genes pbp1+ and pbp2+ homologous to the regulatory subunit B' were isolated. Physical in vivo interaction of the gene products with the catalytic subunit was demonstrated. A double disruption haploid mutant (Deltapbp1Deltapbp2) showed growth defect, cell shape and size abnormality, multiseptation and anucleated cell formation due to abnormality in septum positioning. These phenotypes were suppressed by human B' cDNA, indicating the striking conservation of the B' function from yeast to human. Over-expression of fission yeast B' led to growth defects, a loss of cell shape polarity, septal abnormality and anucleated cell formation. Deltapbp1Deltapbp2 and pbp1 null haploids were hypersensitive to calcineurin inhibitors, cyclosporin A and FK506, with which the mutants underwent arrest at post-anaphase and cell lysis. Double disruption of calcineurin and pbp1+, but not pbp2+, genes led to synthetic lethality.

CONCLUSION

The fission yeast B' subunit of PP2A plays critical roles in cell shape control and septum formation, and shares essential functions with calcineurin for viability, possibly through their roles in cytokinesis and cell wall integrity.

Involvement of polyamines in B cell receptor-mediated apoptosis: spermine functions as a negative modulator

The B cell lymphoma WEHI231 has been used as a model for studying clonal deletion of B cells on the basis of its ability to undergo growth arrest and apoptosis by B cell antigen receptor (BCR) cross-linking. To comprehensively analyze the genes involved in BCR-mediated apoptosis, we applied the technique of serial analysis of gene expression (SAGE) to WEHI231. Comparison of expression patterns revealed that BCR cross-linking caused coordinate changes in the expression of genes involved in polyamine metabolism. Polyamines are ubiquitous compounds required for cell proliferation and homeostasis. The coordinate expression of the polyamine-related genes was confirmed by semiquantitative reverse transcriptase-polymerase chain reaction analysis. During apoptosis, the genes involved in polyamine biosynthesis were downregulated, whereas those involved in polyamine catabolism were upregulated, suggesting that intracellular polyamines play a role in BCR-mediated apoptosis. Levels of intracellular putrescine, spermidine, and spermine were reduced after BCR cross-linking. These effects were prevented by concurrent CD40 stimulation, which blocked BCR-mediated apoptosis. Furthermore, addition of spermine could repress the BCR-mediated apoptosis by attenuating the mitochondrial membrane potential (Deltapsim) loss and activation of caspase-7 induced by BCR signaling. These findings strongly suggest that polyamine regulation is involved in apoptosis during B cell clonal deletion.

Novel alpha-amylase that is highly resistant to chelating reagents and chemical oxidants from the alkaliphilic Bacillus isolate KSM-K38

A novel alpha-amylase (AmyK38) was found in cultures of an alkaliphilic Bacillus isolate designated KSM-K38. Based on the morphological and physiological characteristics and phylogenetic position as determined by 16S ribosomal DNA gene sequencing and DNA-DNA reassociation analysis, it was suggested that the isolate was a new species of the genus Bacillus. The enzyme had an optimal pH of 8.0 to 9.5 and displayed maximum catalytic activity at 55 to 60 degrees C. The apparent molecular mass was approximately 55 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the isoelectric point was around pH 4.2. This enzyme efficiently hydrolyzed various carbohydrates to yield maltotriose, maltohexaose, maltoheptaose, and, in addition, maltose as major end products after completion of the reaction. The activity was not prevented at all by EDTA and EGTA at concentrations as high as 100 mM. Moreover, AmyK38 was highly resistant to chemical oxidation and maintained more than 80% of its original activity even after incubation for 1 h in the presence of excess H2O2 (1.8 M).

Reconstitution of human beta-globin locus control region hypersensitive sites in the absence of chromatin assembly

The human beta-globin genes are regulated by the locus control region (LCR), an element composed of multiple DNase I-hypersensitive sites (HS sites) located 5' to the genes. Various functional studies indicate that the LCR confers high-level, position-independent, and copy number-dependent expression to linked globin genes in transgenic mice. However, the structural basis for LCR function is unknown. Here we show that LCR HS sites can be reconstituted in an erythroid cell-specific manner on chromatin-assembled LCR templates in vitro. Surprisingly, HS2 and HS3 are also formed with erythroid proteins in the absence of chromatin assembly, indicating that sensitivity to nucleases is not simply a consequence of nucleosome reorganization. The generation of LCR HS sites in the absence of chromatin assembly leads to the formation of S1- and KMnO(4)-sensitive regions in HS2 and HS3. These sites are also sensitive to S1 nuclease in erythroid cells in vivo, suggesting a distorted DNA structure in the LCR core enhancer elements. Finally, we show that RNA polymerase II initiates transcription in the HS2 and HS3 core enhancer regions in vitro. Transcription in both HS2 and HS3 proceeds in a unidirectional manner. Taken together, the data suggest that erythroid proteins interact with the core enhancer elements, distort the DNA structure, and recruit polymerase II transcription complexes. These results further our understanding of the structural basis for LCR function and provide an explanation for why the LCR core regions are so extremely sensitive to nucleases in erythroid cells.

Immunohistochemical localization of Betacellulin, a member of epidermal growth factor family, in atherosclerotic plaques of human aorta

Betacellulin (BTC), a new member of the EGF family, has been reported to be a potent mitogen for rat vascular smooth muscle cells (SMCs). BTC mRNA is known to be expressed in several human organs. However, the localization of BTC in human vascular tissues has not yet been clarified. We investigated whether or not BTC protein is involved in the pathogenesis of human atherosclerosis. Recombinant human BTC showed a mitogenic activity on cultured human aortic SMCs by measuring [3H]thymidine incorporation. The immunohistochemical localization of BTC, SMCs, macrophages, EGF receptors and ErbB4 was examined in autopsied human aortas. BTC was detected in both intimal and medial SMCs of the aortic wall. The percentage of BTC-positive medial SMCs in early types of atherosclerotic lesions decreased with age, but in adult, it was significantly higher in advanced types than in early types of atherosclerotic lesions. BTC-positive SMCs were predominantly localized in the medial side of the intima. Furthermore, numerous BTC-positive SMCs and macrophages were observed around the core lesion of atherosclerotic plaques. Receptors for BTC, EGF receptor and ErbB4, were expressed on SMCs, suggesting that BTC is associated with EGF receptor family-mediated signaling. BTC is produced in human aortic tissue and might play important roles in atherogenesis.

Polyamine uptake systems in Escherichia coli

The polyamine content of cells is regulated by biosynthesis, degradation, and transport. In Escherichia coli, the genes for three different polyamine transport systems have been cloned and characterized. Two uptake systems (putrescine-specific and spermidine-preferential) are ABC transporters, each consisting of a periplasmic substrate binding protein, two transmembrane proteins, and a membrane-associated ATPase. The third transport system, catalyzed by PotE, mediates both uptake and excretion of putrescine. In this article, the properties of the first two polyamine uptake systems are reviewed in detail.

Polyamine cytotoxicity in the presence of bovine serum amine oxidase

The toxicity of extracellular spermine, determined in the presence of fetal calf serum, was studied using three cell lines: FM3A, L1210, and NIH3T3 cells. Amine oxidase in fetal calf serum produces aminodialdehyde generating acrolein spontaneously, H(2)O(2), and ammonia from spermine. Spermine toxicity was prevented by aldehyde dehydrogenase, but not by catalase. Similar concentrations of spermine and acrolein were needed to produce toxicity. Other aldehydes (formaldehyde, acetaldehyde, and propionaldehyde) and hydrogen peroxide were less toxic than acrolein. Spermidine and 3-aminopropanal, which produces acrolein, also exhibited severe cytotoxicity. The degree of cytotoxicity of spermine, spermidine, and 3-aminopropanal was nearly parallel with the amount of acrolein produced from each compound. Thus, it was deduced that acrolein is a major toxic compound produced from polyamines (spermine and spermidine) by amine oxidase.

Transcription factor BACH1 is recruited to the nucleus by its novel alternative spliced isoform

The transcription factor Bach1 is a member of a novel family of broad complex, tramtrack, bric-a-brac/poxvirus and zinc finger (BTB/POZ) basic region leucine zipper factors. Bach1 forms a heterodimer with MafK, a member of the small Maf protein family (MafF, MafG, and MafK), which recognizes the NF-E2/Maf recognition element, a cis-regulatory motif containing a 12-O-tetradecanoylphorbol-13-acetate-responsive element. Here we describe the gene structure of human BACH1, including a newly identified promoter and an alternatively RNA-spliced truncated form of BACH1, designated BACH1t, abundantly transcribed in human testis. The alternate splicing originated from the usage of a novel exon located 5.6 kilobase pairs downstream of the exon encoding the leucine zipper domain, and produced a protein that contained the conserved BTB/POZ, Cap'n collar, and basic region domains, but lacked the leucine zipper domain essential for NF-E2/Maf recognition element binding. Subcellular localization studies using green fluorescent protein as a reporter showed that full-length BACH1 localized to the cytoplasm, whereas BACH1t accumulated in the nucleus. Interestingly, coexpression of BACH1 and BACH1t demonstrated interaction between the molecules and the induction of nuclear import of BACH1. These results suggested that BACH1t recruits BACH1 to the nucleus through BTB domain-mediated interaction.

A serpin with M(r) 43,000 is a binding protein of M(r) 25,000 protein, a substrate for protein ser/thr kinase detected in Xenopus laevis oocytes

In an attempt to get some clue as to the function of M(r) 25,000 protein, a protein Ser/Thr kinase substrate detected in Xenopus laevis oocytes [Hashimoto, E. et al. (1995) J. Biochem. 118, 453-460], the binding protein was surveyed using the (32)P-labeled protein by casein kinase II as a screening probe. When the cytosolic proteins from oocytes were transferred to a polyvinylidene fluoride membrane and incubated with the labeled protein, only one protein with M(r) 43,000 was visualized on autoradiography. This protein was purified to a nearly homogeneous state through several column chromatography steps. The amino acid sequence of the amino-terminal region of this protein identified it as a kind of serine protease inhibitor (serpin) [Holland, L.J. et al. (1992) J. Biol. Chem. 267, 7053-7059]. However, the M(r) 25,000 protein did not have any effect on the inhibitory action of this serpin on alpha-chymotrypsin. In addition, several binding proteins were also detected in the particulate fraction of oocytes, although the exact identity of these proteins is not clear at this time. These results suggest that the M(r) 25,000 protein may play some role(s) by interacting with these binding proteins in Xenopus oocytes.

Multiple polyamine transport systems on the vacuolar membrane in yeast

We recently identified a gene (TPO1, YLL028w) that encodes a polyamine transport protein on the vacuolar membrane in yeast [Tomitori, Kashiwagi, Sakata, Kakinuma and Igarashi (1999) J. Biol. Chem. 274, 3265-3267]. Because the existence of one or more other genes for a polyamine transport protein on the vacuolar membrane was expected, we searched sequence databases for homologues of the protein encoded by TPO1. Membrane proteins encoded by the open reading frames YGR138c (TPO2), YPR156c (TPO3) and YOR273c (TPO4) were postulated to be polyamine transporters and, indeed, were subsequently shown to be polyamine transport proteins on the vacuolar membrane. Cells overexpressing these genes were resistant to polyamine toxicity and showed an increase in polyamine uptake activity and polyamine content in vacuoles. Furthermore, cells in which these genes were disrupted showed an increased sensitivity to polyamine toxicity and a decrease in polyamine uptake activity and polyamine content in vacuoles. Resistance to polyamine toxicity in cells overexpressing the genes was overcome by bafilomycin A(1), an inhibitor of the vacuolar H(+)-ATPase. Among the four polyamine transporters, those encoded by TPO2 and TPO3 were specific for spermine, whereas those encoded by TPO1 and TPO4 recognized spermidine and spermine. These results suggest that polyamine content in the cytoplasm of yeast is elaborately regulated by several polyamine transport systems in vacuoles. Furthermore, it was shown that Glu-207, Glu-324 (or Glu-323) and Glu-574 of TPO1 protein were important for the transport activity.

[Lung involvement in rapidly progressive glomerulonephritis]

The purpose of this study is to evaluate pulmonary involvement in rapidly progressive glomerulonephritis (RPGN). Of 71 patients in whom RPGN was diagnosed, 32 (45.1%) had pulmonary involvement: 12, alveolar hemorrhage (AH) (16.9%); 10, interstitial pneumonia (IP) (14.1%); four, chronic bronchial lesions (5.6%); two, consolidation (2.8%), and four, old inflammatory lesions (5.6%). Investigation of which organ of the twelve AH patients, the kidney or the lung, was the first to be involved, showed that the lung preceded in one patient, the kidney was first in three, and the lung and kidney occurred at the same time in the other eight. Of the ten IP patients, the lung preceded in eight, the kidney was ahead in two, and lung and kidney were simultaneous in one. Three patients had a history of pneumoconiosis, and two had acute progressive IP. Seventeen (45.9%) of 37 patients who tested positive for antineutrophil cytoplasmic autoantibodies (MPO-ANCA) had lung involvement, and three (30.0%) of the ten patients who tested negative for MPO-ANCA, PR 3-ANCA and anti-GBM antibody also had lung involvement.

Massive subchorionic hematoma (Breus' mole) complicated by intrauterine growth retardation

We present here a case of massive subchorionic hematoma complicated by intrauterine growth retardation and oligohydramnios diagnosed at 22 weeks' gestation. The patient was managed with the following medications: (1) tocolysis with ritodrine infusion, (2) 10%maltose infusion therapy (1500mL/day), (3) antibiotic infusion (cefotaxim sodium, 2 g/dayx7) and (4) kampo therapy with Sairei-to until delivery. At 33 weeks and 0 days' gestation, a female baby weighing 1,342 g was delivered without complication by caesarean section. During surgery, an escape of about 500~600 g of dark brown blood with no clots was noted from the subchorionic space of the placenta. Examination of the placenta showed a large fibrosis with well-defined margins on the fetal surface.

Alpha-tocopherol transfer protein is important for the normal development of placental labyrinthine trophoblasts in mice

Alpha-tocopherol transfer protein (alpha-TTP), a cytosolic protein that specifically binds alpha-tocopherol, is known as a product of the causative gene in patients with ataxia that is associated with vitamin E deficiency. Targeted disruption of the alpha-TTP gene revealed that alpha-tocopherol concentration in the circulation was regulated by alpha-TTP expression levels. Male alpha-TTP(-/-) mice were fertile; however, placentas of pregnant alpha-TTP(-/-) females were severely impaired with marked reduction of labyrinthine trophoblasts, and the embryos died at mid-gestation even when fertilized eggs of alpha-TTP(+/+) mice were transferred into alpha-TTP(-/-) recipients. The use of excess alpha-tocopherol or a synthetic antioxidant (BO-653) dietary supplement by alpha-TTP(-/-) females prevented placental failure and allowed full-term pregnancies. In alpha-TTP(+/+) animals, alpha-TTP gene expression was observed in the uterus, and its level transiently increased after implantation (4.5 days postcoitum). Our results suggest that oxidative stress in the labyrinth region of the placenta is protected by vitamin E during development and that in addition to the hepatic alpha-TTP, which governs plasma alpha-tocopherol level, the uterine alpha-TTP may also play an important role in supplying this vitamin.

Potassium uptake with low affinity and high rate in Enterococcus hirae at alkaline pH

Two high-affinity K+ uptake systems, KtrI and KtrII, have been reported in Enterococcus hirae. A mutant, JEMK1, defective in these two systems did not grow at pH 10 in low-K+ medium (less than 1 mM K+), but grew well when supplemented with 10 mM KCl. In this mutant, we found an energy-dependent K+ uptake at pH 10 with a low affinity for K+ (Km of approximately 20 mM) and an extremely high rate [Vmax of 1.6 micromol x min(-1) (mg protein)(-1)]. Rb+ uptake [Km of approximately 40 mM and Vmax of 0.5 micromol x min(-1) (mg protein)(-1)], which was inhibited competitively by K+ and less prominently by Cs+, was also observed. The specificity of this transport is likely to be K+>Rb+>Cs+. This peculiar K+ transport plays a role as a salvage mechanism against defects in high-affinity systems in the K+ homeostasis of this bacterium.

Recombinant human betacellulin promotes the neogenesis of beta-cells and ameliorates glucose intolerance in mice with diabetes induced by selective alloxan perfusion

Betacellulin (BTC), a member of the epidermal growth factor family, is expressed predominantly in the human pancreas and induces the differentiation of a pancreatic acinar cell line (AR42J) into insulin-secreting cells, suggesting that BTC has a physiologically important role in the endocrine pancreas. In this study, we examined the in vivo effect of recombinant human BTC (rhBTC) on glucose intolerance and pancreatic morphology using a new mouse model with glucose intolerance induced by selective alloxan perfusion. RhBTC (1 microg/g body wt) or saline was injected subcutaneously every day from the day after alloxan treatment. The intraperitoneal glucose tolerance test revealed no difference between rhBTC-treated and rhBTC-untreated glucose-intolerant mice at 2-4 weeks. However, glucose tolerance was significantly improved and body weight was significantly increased in rhBTC-treated mice compared with untreated mice at 8 weeks. Islet-like cell clusters, consisting mainly of beta-cells, were increased in the pancreas and were localized in contact with the ductal lining cells and sometimes with acinar cells. In conclusion, administration of rhBTC improved glucose tolerance in this mouse model by increasing beta-cell volume, primarily through accelerated neogenesis from ductal lining cells.

Identification of the putrescine recognition site on polyamine transport protein PotE

The PotE protein can catalyze both uptake and excretion of putrescine. The K(m) values of putrescine for uptake and excretion are 1.8 and 73 microm, respectively. Uptake of putrescine is dependent on the membrane potential, whereas excretion involves putrescine-ornithine antiporter activity. Amino acids involved in both activities were identified using mutated PotE proteins. It was found that Cys(62), Trp(201), Trp(292), and Tyr(425) were strongly involved in both activities, and that Tyr(92), Cys(210), Cys(285), and Cys(286) were moderately involved in the activities. Mutations of Tyr(78), Trp(90), and Trp(422) mainly affected uptake activity, and the K(m) values for putrescine uptake by these PotE mutants increased greatly, indicating that these amino acids are involved in the high affinity uptake of putrescine by PotE. Mutations of Lys(301) and Tyr(308) mainly affected excretion activity (putrescine-ornithine antiporter activity), and excretion by these mutants was not stimulated by ornithine, indicating that these amino acids are involved in the recognition of ornithine. It was found that the putrescine and ornithine recognition site on PotE is located at the cytoplasmic surface and the vestibule of the pore consisting of 12 transmembrane segments. Based on the results of competition experiments with various putrescine analogues and the disulfide cross-linking of PotE between cytoplasmic loops and the COOH terminus, a model of the putrescine recognition site on PotE consisting of the identified amino acids is presented.

Suppression of rat thromboxane synthase gene transcription by peroxisome proliferator-activated receptor gamma in macrophages via an interaction with NRF2

We have studied the transcription regulation of the rat thromboxane synthase (TXS) gene by peroxisome proliferator-activated receptor gamma (PPARgamma) in macrophages. The transcription activity of a cloned 5'-flanking region (1.6 kilobases) of the rat TXS gene (5'FL-TXS) was examined by luciferase reporter gene assay. TXS mRNA expression and the transcription activity of 5'FL-TXS were inhibited by PPARgamma ligands, 15-deoxy-Delta(12,14)-prostaglandin J(2) (PGJ(2)), and the thiazolidinedione troglitazone (TRO) in a dose-dependent manner. Overexpression of PPARgamma also significantly suppressed transcription, and further addition of PGJ(2) or TRO augmented the suppression. Deletion analysis showed that the element responsible for the PPARgamma effect is located in a region containing the nuclear factor E2 (NF-E2)/AP-1 site (-98/-88), which was indicated to be the major promoter of the TXS gene. By electrophoretic mobility shift assay using the NF-E2/AP-1 site and nuclear extracts from macrophages, we observed a specific protein-DNA complex formation, which was inhibited by a specific antibody against the transcription factor NRF2 (NF-E2-related factor 2). Moreover, the complex was decreased with PGJ(2), TRO, or in vitro translated PPARgamma. The transcription suppression by PPARgamma was confirmed using this truncated NRF2-binding element (-98/-88) by the reporter gene assay. Finally, a direct interaction between PPARgamma and NRF2 was confirmed by glutathione S-transferase pull-down assay. In conclusion, the NRF2-binding site (-98/-88) is the major promoter of 5'FL-TXS which can be suppressed by activated PPARgamma via a protein-protein interaction with NRF2 in macrophages.

Differentiation of Toxocara canis and T. cati eggs by light and scanning electron microscopy

In this study, we investigated the morphological identification of Toxocara canis and T. cati eggs on the basis of light and scanning electron microscopic (SEM) observations. T. canis and T. cati eggs used in this study were recovered from the uteri of respective gravid female worms. Measurement of egg size was not helpful in the differentiation of these species, because approximately 90% of eggs measured were of similar size. Using SEM, we were able to differentiate T. canis eggs from T. cati eggs based on their respective characteristic surface structures. Both species have subspherical eggs with markedly pitted surfaces like those of a golf ball, but the surface pitting in T. canis is more coarse than that in T. cati. In this study, however, these differences were not absolute, as 16% of T. canis and 29% of T. cati eggs showed surface pitting that was uncharacteristic of their species. Of the 16% of T. canis eggs that could not be differentiated by surface structure, 3% had pitting resembling T. cati, and the remaining 13% showed intermediate type surface pitting. Similarly, 5% of T. cati eggs resembled T. canis, and 25% of these were of intermediate type. Light microscopic observation yielded results similar to those of SEM, indicating that light microscopy is also a useful tool for the identification of Toxocara eggs.

Increase in cap- and IRES-dependent protein synthesis by overproduction of translation initiation factor eIF4G

The role of eIF4G during the initiation of protein synthesis was studied using mouse mammary carcinoma FM3A cells and FM4G cells that overproduce an N-terminally truncated form of eIF4G, which lacks the binding site of poly(A)-binding protein. An increase in eIF4G was correlated with an increase in protein synthesis and RNA helicase activity. Translation of mRNAshaving both short and long 5'-untranslated regions (5'-UTR) increased significantly in FM4G cells compared to that in FM3A cells. Both full-length and N-terminally truncated eIF4G transfectants of NIH3T3 cells formed colonies in soft agar and increased the saturation density of cell growth, indicating that both eIF4Gs function similarly. We also found that an internal ribosome entry site (IRES) exists in the 5'-UTR of ornithinedecarboxylase mRNA and that IRES-dependent protein synthesis increased in FM4G cells. Our results indicate that an increase in eIF4G contributes to the formation of active eIF4F similarly to that caused by an increase in eIF4E, as well as to a stimulation of IRES-dependent protein synthesis.

Brain metastasis as a sole recurrence of prostate cancer after total prostatectomy

Brain metastasis from prostate cancer is a rare clinical event. We present a case of prostate cancer with a solitary brain metastasis as a sole site of recurrence after total prostatectomy. To our knowledge, this is the third reported case of an isolated brain metastasis from prostate cancer.

Hepatocellular carcinoma cell cycle: study of Long-Evans cinnamon rats

Amplification found in a number of cyclin genes, especially in cyclin D and E, is an important event process that takes place in cancers, including hepatocellular carcinoma (HCC). The activities of a wide range of cell cycle-related kinases remain obscure in HCC. The purpose of the present study is to determine the cyclins and kinase activities of HCC in Long-Evans Cinnamon (LEC) rats. Cyclin D1, E, A, H, Cdk1(cyclin-dependent kinase; Cdc2), Cdk4, and Cdk6 protein levels were determined by Western blot analysis at different pathologic stages of liver tissues exhibiting HCC. Enzymatic activities of cyclin D1, E, A, Cdk4, Cdk6, Cdc2, Cdk7, and Wee1 kinase were measured by in-gel kinase assay. Protein levels and kinase activities of cyclin D1, E, Cdk4, cyclin A, and Wee1 increased proportionally with the development of HCC, especially in the transition process from chronic hepatitis to HCC. Although Cdc2 kinase activity was found to increase slightly from normal liver to chronic hepatitis, its activity remained unchanged in the process from chronic hepatitis to HCC. Cdk6 and Cdk7 activities remained unchanged in the process from normal liver to HCC. These data suggest that the increase in Cdc2 kinase may play a role in the process from normal liver to chronic hepatitis, whereas the predominant increase in cyclin D1, Cdk4, cyclin E, cyclin A, and Wee1 suggests involvement not only in the process from normal liver to chronic hepatitis, but also during transition into HCC.

Coronary artery-left ventricle fistula complicating balloon angioplasty--a case report

The authors describe a coronary artery fistula complicated balloon angioplasty. The proximal left anterior descending coronary artery was dilated, but a septal branch was occluded by thrombus. Angioplasty was used on the septal branch, but a pseudoaneurysm communicating with the left ventricle occurred. Follow-up angiography revealed spontaneous closure of the fistula.

Evolution of left ventricular involvement in arrhythmogenic right ventricular cardiomyopathy

Left ventricular (LV) involvement in arrhythmogenic right ventricular cardiomyopathy (ARVC) is fairly well known, but the evolution of LV involvement during long-term follow-up has not been well documented. We describe such evolution in a patient followed for 9 years. Evolution was confirmed by a progressive perfusion defect of the LV wall in myocardial scintigrams and by the development of LV asynergy with ventricular aneurysm formation in left ventriculograms. As the right ventricle progressively enlarged, we concluded that ARVC is a diffuse and progressive myocardial disease that affects both ventricles.