Transient left ventricular apical ballooning without coronary artery stenosis: a novel heart syndrome mimicking acute myocardial infarction. Angina Pectoris-Myocardial Infarction Investigations in Japan

OBJECTIVES

To determine the clinical features of a novel heart syndrome with transient left ventricular (LV) apical ballooning, but without coronary artery stenosis, that mimics acute myocardial infarction, we performed a multicenter retrospective enrollment study.

BACKGROUND

Only several case presentations have been reported with regard to this syndrome.

METHODS

We analyzed 88 patients (12 men and 76 women), aged 67 +/- 13 years, who fulfilled the following criteria: 1) transient LV apical ballooning, 2) no significant angiographic stenosis, and 3) no known cardiomyopathies.

RESULTS

Thirt-eight (43%) patients had preceding aggravation of underlying disorders (cerebrovascular accident [n = 3], epilepsy [n = 3], exacerbated bronchial asthma [n = 3], acute abdomen [n = 7]) and noncardiac surgery or medical procedure (n = 11) at the onset. Twenty-four (27%) patients had emotional and physical problems (sudden accident [n = 2], death/funeral of a family member [n = 7], inexperience with exercise [n = 6], quarreling or excessive alcohol consumption [n = 5] and vigorous excitation [n = 4]). Chest symptoms (67%), electrocardiographic changes (ST elevation [90%], Q-wave formation [27%] and T-wave inversion [97%]) and elevated creatine kinase (56%) were found. After treatment of pulmonary edema (22%), cardiogenic shock (15%) and ventricular tachycardia/fibrillation (9%), 85 patients had class I New York Heart Association function on discharge. The LV ejection fraction improved from 41 +/- 11% to 64 +/- 10%. Transient intraventricular pressure gradient and provocative vasospasm were documented in 13/72 (18%) and 10/48 (21%) of the patients, respectively. During follow-up for 13 +/- 14 months, two patients showed recurrence, and one died suddenly.

CONCLUSIONS

A novel cardiomyopathy with transient apical ballooning was reported. Emotional or physical stress might play a key role in this cardiomyopathy, but the precise etiologic basis still remains unclear.

Complete genome sequence of enterohemorrhagic Escherichia coli O157:H7 and genomic comparison with a laboratory strain K-12

Escherichia coli O157:H7 is a major food-borne infectious pathogen that causes diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. Here we report the complete chromosome sequence of an O157:H7 strain isolated from the Sakai outbreak, and the results of genomic comparison with a benign laboratory strain, K-12 MG1655. The chromosome is 5.5 Mb in size, 859 Kb larger than that of K-12. We identified a 4.1-Mb sequence highly conserved between the two strains, which may represent the fundamental backbone of the E. coli chromosome. The remaining 1.4-Mb sequence comprises of O157:H7-specific sequences, most of which are horizontally transferred foreign DNAs. The predominant roles of bacteriophages in the emergence of O157:H7 is evident by the presence of 24 prophages and prophage-like elements that occupy more than half of the O157:H7-specific sequences. The O157:H7 chromosome encodes 1632 proteins and 20 tRNAs that are not present in K-12. Among these, at least 131 proteins are assumed to have virulence-related functions. Genome-wide codon usage analysis suggested that the O157:H7-specific tRNAs are involved in the efficient expression of the strain-specific genes. A complete set of the genes specific to O157:H7 presented here sheds new insight into the pathogenicity and the physiology of O157:H7, and will open a way to fully understand the molecular mechanisms underlying the O157:H7 infection.

Mass screening for lung cancer with mobile spiral computed tomography scanner

BACKGROUND

The incidence of and mortality from lung cancer have increased steadily. Most lung cancers are not localised when first detected, but early detection is mandatory to improve prognosis. Since curable early cases are hard to visualise with conventional chest radiography, a new diagnostic means must be found. We assessed whether population-based mass screening with a spiral computed tomography scanner could contribute substantially to detection of smaller cancers, and decrease mortality.

METHODS

In 1996, we screened in a mobile unit 5483 individuals from the general population of Matsumoto, Japan, aged between 40 years and 74 years who had undergone annual chest radiography (miniature fluorophotography) and cytological assessment of sputum. All participants had a low-dose X-ray spiral computed tomography (CT) scan of the thorax; 3967 also underwent miniature fluorophotography. We compared smokers and non-smokers. Further assessments were done for probably benign but suspicious lesions; suspicion of cancer; and indeterminate small nodules by chest radiography and conventional CT, with additional transbronchial biopsy when possible. Thoracotomy was recommended when it was strongly suspected that the patients had lung cancer.

FINDINGS

19 patients were diagnosed as having lung cancer--14 with suspicion of lung cancer, three with benign but suspicious lesions, and two with indeterminate small nodules. 18 cases were surgically confirmed, and one was clinically diagnosed. The mean size of lesions was 17 mm (range 6-47). In four of 19 patients, lung abnormality was seen on CT and miniature fluorophotography. The lung-cancer detection rate with CT was 0.48%, significantly higher than the 0.03-0.05% for standard mass assessments done previously in the same area. CT missed one case that was found solely on a sputum cytology examination.

INTERPRETATION

Our results show that miniature fluorophotography or conventional chest radiography, which have been the main diagnostic techniques for lung cancer, showed few small cancers. CT was more accurate in mass screening for lung cancer and led to early detection and an accurate diagnosis of lung cancer, and should be considered in future health plans.

Excitation spectra of circular, few-electron quantum dots

Studies of the ground and excited states in semiconductor quantum dots containing 1 to 12 electrons showed that the quantum numbers of the states in the excitation spectra can be identified and compared with exact calculations. A magnetic field induces transitions between the ground and excited states. These transitions were analyzed in terms of crossings between single-particle states, singlet-triplet transitions, spin polarization, and Hund's rule. These impurity-free quantum dots allow "atomic physics" experiments to be performed in magnetic field regimes not accessible for atoms.

Cisplatin-incorporating polymeric micelles (NC-6004) can reduce nephrotoxicity and neurotoxicity of cisplatin in rats

In spite of the clinical usefulness of cisplatin (CDDP), there are many occasions in which it is difficult to continue the administration of CDDP due to its nephrotoxicity and neurotoxicity. We examined the incorporation of CDDP into polymeric micelles to see if this allowed the resolution of these disadvantages. Cisplatin was incorporated into polymeric micelles through the polymer-metal complex formation between polyethylene glycol poly(glutamic acid) block copolymers and CDDP (NC-6004). The pharmacokinetics, pharmacodynamics, and toxicity studies of CDDP and NC-6004 were conducted in rats or mice. The particle size of NC-6004 was approximately 30 nm, with a narrow size distribution. In rats, the area under the curve and total body clearance values for NC-6004 were 65-fold and one-nineteenth the values for CDDP (P<0.001 and 0.01, respectively). In MKN-45-implanted mice, NC-6004 tended to show antitumour activity, which was comparable to or greater than that of CDDP. Histopathological and biochemical studies revealed that NC-6004 significantly inhibited the nephrotoxicity of CDDP. On the other hand, blood biochemistry revealed transient hepatotoxicity on day 7 after the administration of NC-6004. Furthermore, rats given CDDP showed a significant delay (P<0.05) in sensory nerve conduction velocity in their hind paws as compared with rats given NC-6004. Electron microscopy in rats given CDDP indicated the degeneration of the sciatic nerve, but these findings were not seen in rats given NC-6004. These results were presumably attributable to the significantly reduced accumulation of platinum in nerve tissue when NC-6004 was administered (P<0.05). NC-6004 preserved the antitumour activity of CDDP and reduced its nephrotoxicity and neurotoxicity, which would therefore seem to suggest that NC-6004 could allow the long-term administration of CDDP where caution against hepatic dysfunction must be exercised.

Results of three-year mass screening programme for lung cancer using mobile low-dose spiral computed tomography scanner

The aim of this study was to evaluate the usefulness of annual screening for lung cancer by low-dose computed tomography (CT) and the characteristics of identified lung cancers. Subjects consisted of 5483 general population aged 40-74 years, who received initial CT scans in 1996, followed by repeat annual scans for most subjects in 1997 and 1998, with a total of 13 786 scans taken during 1996-1998. Work-up examinations for patients with suspicious lesions were conducted using diagnostic CTs. The initial screening in 1996 detected suspicious nodules in 279 (5.1%) of 5483 subjects, and 22 (8%) were confirmed surgically to have lung cancer. Corresponding figures in 1997 and 1998 screening studies were 173 (3.9%) of 4425 and 25 (14%) of 173, and 136 (3.5%) of 3878 and 9 (7%) of 136, respectively. The sensitivity and specificity of detecting surgically confirmed lung cancer were 55% (22/40) and 95% (4960/5199) in 1996 and 83% (25/30) and 97% (4113/4252) in 1997 screening, respectively. 88% (55/60) of lung cancers identified on screening and surgically confirmed were AJCC stage IA. Our trial allowed detection of nearly 11 times the expected annual number of early lung cancers. Repeat CT allowed the detection of more aggressive, rapidly growing lung cancers, compared to those in the initial screening.

Presenilin 1 associates with glycogen synthase kinase-3beta and its substrate tau

Families bearing mutations in the presenilin 1 (PS1) gene develop Alzheimer's disease. Previous studies have shown that the Alzheimer-associated mutations in PS1 increase production of amyloid beta protein (Abeta1-42). We now show that PS1 also regulates phosphorylation of the microtubule-associated protein tau. PS1 directly binds tau and a tau kinase, glycogen synthase kinase 3beta (GSK-3beta). Deletion studies show that both tau and GSK-3beta bind to the same region of PS1, residues 250-298, whereas the binding domain on tau is the microtubule-binding repeat region. The ability of PS1 to bring tau and GSK-3beta into close proximity suggests that PS1 may regulate the interaction of tau with GSK-3beta. Mutations in PS1 that cause Alzheimer's disease increase the ability of PS1 to bind GSK-3beta and, correspondingly, increase its tau-directed kinase activity. We propose that the increased association of GSK-3beta with mutant PS1 leads to increased phosphorylation of tau.

The carboxyl third of tau is tightly bound to paired helical filaments

To obtain definitive evidence that tau is a component of paired helical filaments (PHF) in Alzheimer's disease, we fractionated and sequenced PHF-derived peptides according to a previously described procedure. In the PHF digest, we found four independent tau peptides that were located in the carboxyl third of tau. Subsequent extensive analysis of the PHF digest did not provide any other tau peptides. The conventional PHF antiserum and a new antiserum directed toward formic acid-denatured PHF reacted with the distinct CNBr fragments of tau localized on the carboxy-terminal portion of tau by protein sequencing. From these observations, we conclude that the carboxyl third of tau is tightly bound to PHF.

BAS1: A gene regulating brassinosteroid levels and light responsiveness in Arabidopsis

The Arabidopsis bas1-D mutation suppresses the long hypocotyl phenotype caused by mutations in the photoreceptor phytochrome B (phyB). The adult phenotype of bas1-D phyB-4 double mutants mimics that of brassinosteroid biosynthetic and response mutants. bas1-D phyB-4 has reduced levels of brassinosteroids and accumulates 26-hydroxybrassinolide in feeding experiments. The basis for the mutant phenotype is the enhanced expression of a cytochrome P450 (CYP72B1). bas1-D suppresses a phyB-null allele, but not a phyA-null mutation, and partially suppresses a cryptochrome-null mutation. Seedlings with reduced BAS1 expression are hyperresponsive to brassinosteroids in a light-dependent manner and display reduced sensitivity to light under a variety of conditions. Thus, BAS1 represents one of the control points between multiple photoreceptor systems and brassinosteroid signal transduction.

Calcium-activated neutral proteinase (calpain) system in aging and Alzheimer's disease

Calpains (CANPs) are a family of calcium-dependent cysteine proteases under complex cellular regulation. By making selective limited proteolytic cleavages, they activate or alter the regulation of certain enzymes, including key protein kinases and phosphatases, and induce specific cytoskeletal rearrangements, accounting for their suspected involvement in intracellular signaling, vesicular trafficking, and structural stabilization. Calpain activity has been implicated in various aging phenomena, including cataract formation and erythrocyte senescence. Abnormal activation of the large stores of latent calpain in neurons induces cell injury and is believed to underlie neurodegeneration in excitotoxicity, Wallerian degeneration, and certain other neuropathologic states involving abnormal calcium influx. In Alzheimer's disease, we found the ratio of activated calpain I to its latent precursor isoform in neocortex to be threefold higher than that in normal individuals and those with Huntington's or Parkinson's disease. Immunoreactivity toward calpastatin, the endogenous inhibitor of calpain, was also markedly reduced in layers II-V of the neocortex in Alzheimer's disease. The excessive calpain system activation suggested by these findings represents a potential molecular basis for synaptic loss and neuronal cell death in the brain in Alzheimer's disease given the known destructive actions of calpain I and its preferential neuronal and synaptic localization. In surviving cells, persistent calpain activation may also contribute to neurofibrillary pathology and abnormal amyloid precursor protein trafficking/processing through its known actions on protein kinases and the membrane skeleton. The degree of abnormal calpain activation in the brain in Alzheimer's disease strongly correlated with the extent of decline in levels of secreted amyloid precursor protein in brain. Cytoskeletal proteins that are normally good calpain substrates become relatively calpain resistant when they are hyperphosphorylated, which may contribute to their accumulation in neurofibrillary tangles. As a major effector of calcium signals, calpain activity may mirror disturbances in calcium homeostasis and mediate important pathologic consequences of such disturbances.

Detailed images of asteroid 25143 Itokawa from Hayabusa

Rendezvous of the Japanese spacecraft Hayabusa with the near-Earth asteroid 25143 Itokawa took place during the interval September through November 2005. The onboard camera imaged the solid surface of this tiny asteroid (535 meters by 294 meters by 209 meters) with a spatial resolution of 70 centimeters per pixel, revealing diverse surface morphologies. Unlike previously explored asteroids, the surface of Itokawa reveals both rough and smooth terrains. Craters generally show unclear morphologies. Numerous boulders on Itokawa's surface suggest a rubble-pile structure.

Activation of tau protein kinase I/glycogen synthase kinase-3beta by amyloid beta peptide (25-35) enhances phosphorylation of tau in hippocampal neurons

According to the amyloid hypothesis for the pathogenesis of Alzheimer's disease (AD), amyloid beta peptide (Abeta) directly affects neurons, leading to neurodegeneration and tau phosphorylation, followed by the production of paired helical filaments (PHF) in neurofibrillary tangles (NFT). To analyze the relationship between the phosphorylation sites of tau and the activation of kinases in response to Abeta, we treated cultured rat hippocampal neurons with a peptide fragment of Abeta, Abeta(25-35). Abeta(25-35) treatment activated tau protein kinase I/glycogen synthase kinase-3beta (TPKI/GSK-3beta) but not glycogen synthase kinase-3alpha (GSK-3alpha) or mitogen activated protein kinase (MAP kinase) in primary culture of hippocampal neurons. Using antibodies that recognize phosphorylated sites of tau, we showed that tau phosphorylation was enhanced in at least five sites (Ser199, Ser202, Ser396, Ser404, and Ser413 numbered according to the human tau isoform containing 441 amino acid residues), to an extent that depended on the level of TPK I/GSK-3beta. Treatment with TPK I/GSK-3beta antisense oligonucleotide inhibited the enhancement of tau phosphorylation induced by Abeta(25-35) exposure. Thus, TPK I/GSK-3beta activation by Abeta(25-35) may lead to extensive tau phosphorylation.

Purification and characterization of a hemolysin produced by a clinical isolate of Kanagawa phenomenon-negative Vibrio parahaemolyticus and related to the thermostable direct hemolysin

A clinical isolate (strain 4037) of Kanagawa phenomenon-negative Vibrio parahaemolyticus was studied. Although the strain was judged to be Kanagawa phenomenon-negative by various conventional tests, it produced a new hemolysin (named Vp-TRH, for thermostable direct hemolysin [Vp-TDH]-related hemolysin) that was related to the Vp-TDH produced by ordinary Kanagawa phenomenon-positive V. parahaemolyticus. Vp-TRH was purified by ammonium sulfate fractionation and successive column chromatographies on DEAE-cellulose, hydroxyapatite, and Mono Q. The molecular weight of Vp-TRH was estimated as 48,000 by Sephadex G-100 gel filtration, and the molecular weight of the subunit was estimated to be 23,000 by sodium dodecyl sulfate-slab gel electrophoresis. Thus, like Vp-TDH, Vp-TRH seems to be composed of two subunits. The isoelectric point of Vp-TRH was determined to be 4.6. Vp-TRH showed lytic activities different from those of Vp-TDH on erythrocytes from various animals, especially those from calves, chickens, and sheep. The hemolytic activity of Vp-TRH was labile on heat treatment at 60 degrees C for 10 min, unlike that of Vp-TDH. The immunological similarities, but not the identities of Vp-TRH and Vp-TDH, were demonstrated by Ouchterlony, neutralization, and latex agglutination tests. Thus, we conclude that this clinical isolate of Kanagawa phenomenon-negative V. parahaemolyticus produces a new type of hemolysin that is similar, but not identical, to Vp-TDH, which is usually produced by Kanagawa phenomenon-positive V. parahaemolyticus.

Synthetic oleanane and ursane triterpenoids with modified rings A and C: a series of highly active inhibitors of nitric oxide production in mouse macrophages

We have designed and synthesized 16 new olean- and urs-1-en-3-one triterpenoids with various modified rings C as potential antiinflammatory and cancer chemopreventive agents and evaluated their inhibitory activities against production of nitric oxide induced by interferon-gamma in mouse macrophages. This investigation revealed that 9(11)-en-12-one and 12-en-11-one functionalities in ring C increase the potency by about 2-10 times compared with the original 12-ene. Subsequently, we have designed and synthesized novel olean- and urs-1-en-3-one derivatives with nitrile and carboxyl groups at C-2 in ring A and with 9(11)-en-12-one and 12-en-11-one functionalities in ring C. Among them, we have found that methyl 2-cyano-3, 12-dioxooleana-1,9(11)-dien-28-oate (25), 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO) (26), and methyl 2-carboxy-3,12-dioxooleana-1,9(11)-dien-28-oate (29) have extremely high potency (IC(50) = 0.1 nM level). Their potency is similar to that of dexamethasone although they do not act through the glucocorticoid receptor. Overall, the combination of modified rings A and C increases the potency by about 10 000 times compared with the lead compound, 3-oxooleana-1,12-dien-28-oic acid (8) (IC(50) = 1 microM level). The selected oleanane triterpenoid, CDDO (26), was found to be a potent, multifunctional agent in various in vitro assays and to show antiinflammatory activity against thioglycollate-interferon-gamma-induced mouse peritonitis.

The coxsackievirus-adenovirus receptor protein as a cell adhesion molecule in the developing mouse brain

In an attempt to elucidate the molecular mechanisms underlying neuro-network formation in the developing brain, we analyzed 130 proteolytic cleavage peptides of membrane proteins purified from newborn mouse brains. We describe here the characterization of a membrane protein with an apparent molecular mass of 46 kDa, a member of the immunoglobulin superfamily of which the cDNA sequence was recently reported, encoding the mouse homologue of the human coxsackievirus and adenovirus receptor (mCAR). Western and Northern blot analyses demonstrated the abundant expression of mCAR in the mouse brain, the highest level being observed in the newborn mouse brain, and its expression was detected in embryos as early as at 10. 5 days post-coitus (dpc), but decreased rapidly after birth. On in situ hybridization, mCAR mRNA expression was observed throughout the newborn mouse brain. In primary neurons from the hippocampi of mouse embryos the expression of mCAR was observed throughout the cells including those in growth cones on immunohistochemistry. In order to determine whether or not mCAR is involved in cell adhesion, aggregation assays were carried out. C6 cells transfected with mCAR cDNA aggregated homophilically, which was inhibited by specific antibodies against the extracellular domain of mCAR. In addition to its action as a virus receptor, mCAR may function naturally as an adhesion molecule involved in neuro-network formation in the developing nervous system.

A filamentous phage associated with recent pandemic Vibrio parahaemolyticus O3:K6 strains

A specific serotype, O3:K6, of Vibrio parahaemolyticus has recently been causing epidemics of gastroenteritis in Southeast Asia, Japan, and North America. To examine whether the new O3:K6 strains possess characteristics that may exacerbate outbreaks, we compared V. parahaemolyticus O3:K6 strains with non-O3:K6 strains using strains isolated from individuals with traveler's diarrhea at Kansai Airport Quarantine Station, Osaka, Japan. All 24 O3:K6 strains possessed a common plasmid, pO3K6 (DNA size, 8,782 bp, with 10 open reading frames [ORFs]). The gene organization of pO3K6 was similar to that of Vf33, a filamentous phage previously described in V. parahaemolyticus. We isolated a phage (phage f237) from the culture supernatant of V. parahaemolyticus O3:K6 strain KXV237, which formed a turbid plaque on an indicator strain. The genome of f237 was single-stranded DNA, and the double-stranded DNA obtained by treatment of the genome with DNA polymerase was identical to that of pO3K6 when analyzed by agarose gel electrophoresis after HindIII digestion. Furthermore, the N-terminal amino acid sequence of the f237 major coat protein was found in ORF4 of pO3K6. Our results showed that pO3K6 is a replicative form of f237. Among the ORFs found in the f237 genome, the sequence of ORF8 had no significant homology to those of any proteins in databases. ORF8 was located on a region corresponding to the distinctive region of Vf33, and its G+C content was apparently lower than that of the remaining DNA sequence of f237. By colony hybridization, ORF8 was detected only in O3:K6 strains isolated since 1996 and was not found in O3:K6 strains isolated before 1996 and clinical V. parahaemolyticus strains other than those of serotype O3:K6. Thus, this study shows that f237 is exclusively associated with recent V. parahaemolyticus O3:K6 strains. The ORF8 gene can be a useful genetic marker for the identification of the recently widespread O3:K6 strains of V. parahaemolyticus.

Design and synthesis of 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid, a novel and highly active inhibitor of nitric oxide production in mouse macrophages

New derivatives with electron-withdrawing substituents at the C-2 position of 3-oxoolean-1-en-28-oic acid were synthesized. Among them, 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO) was 400 times more potent than previous compounds we have made as an inhibitor of production of nitric oxide induced by interferon-gamma in mouse macrophages (IC50, 0.4 nM). The potency of CDDO was similar to that of dexamethasone, although CDDO does not act through the glucocorticoid receptor.

Regulation of reactive oxygen species-induced apoptosis and necrosis by caspase 3-like proteases

Reactive oxygen species (ROS) and caspases have been implicated as potential mediators of cell death. However, their mechanistic relationship remains to be elucidated. Here we investigated the roles of caspases in apoptosis and necrosis induced by ROS, generated by the mixture of xanthine and xanthine oxidase (X/XO). A low concentration of XO (0.025 U/ml) induced DNA fragmentation with little cellular membrane damage 3 h after treatment, suggesting the induction of apoptosis. The same treatment induced membrane blebbing, a morphological change typical of apoptosis, 15 min after treatment. A high concentration of XO (0.1 U/ml) damaged cell membranes with little concomitance of DNA fragmention, suggesting the induction of necrosis. ROS also activated caspase 3-like proteases and caspase 3 itself together with the release of cytochrome c which might be the cause of caspase activation. Apoptosis induced by low concentrations of XO and necrosis induced by high concentrations of XO was inhibited by z-DEVD-CH2F, an irreversible inhibitor of caspase 3. However, rapid induction of membrane blebbing was not inhibited by z-DEVD-CH2F. These results suggest that both apoptosis and necrosis could be induced by ROS through the activation of caspase 3-like protease; however, caspase 3 activation is not needed for ROS-induced membrane blebbing.

High-resolution CT analysis of small peripheral lung adenocarcinomas revealed on screening helical CT

OBJECTIVE

The purpose of this study was to determine the correlation between high-resolution CT morphologic features of small peripheral lung adenocarcinomas and tumor growth patterns.

MATERIALS AND METHODS

We examined high-resolution CT morphologic features of 59 small, surgically resected peripheral lung adenocarcinomas (diameter, 6-20 mm) that were detected on screening for lung cancer using low-dose helical CT. Among these adenocarcinomas, 14 (24%) were visible and 45 (76%) were invisible on conventional chest radiography. The correlation between high-resolution CT morphologic features and tumor growth patterns was analyzed.

RESULTS

Sixteen (94%) of 17 type A (Noguchi's classification) adenocarcinomas appeared as nodules of pure ground-glass attenuation (high-resolution CT type I). Ten (71%) of 14 type B tumors appeared as heterogeneous, low-attenuation nodules (type II). Seven (29%) of 24 type C tumors appeared as nodules with ground-glass attenuation in the periphery and a high-density central zone (type III), and 12 (50%) of 24 type C tumors appeared as homogeneous nodules with soft-tissue density (type IV). Among tumors with a replacement growth pattern, the size and CT values of type C tumors were larger than those of type A or type B tumors (p < 0.05), whereas the percentage of ground-glass attenuation and retained air space in type C tumors was smaller than those in type A or type B tumors (p < 0.01). All (100%) four type D tumors appeared to be homogeneous nodules with soft-tissue density (type IV).

CONCLUSION

Small peripheral lung adenocarcinomas shown on CT exhibit four high-resolution CT patterns that corresponded to the histopathologic findings of different tumor growth patterns.

Complete nucleotide sequences of 93-kb and 3.3-kb plasmids of an enterohemorrhagic Escherichia coli O157:H7 derived from Sakai outbreak

Enterohemorrhagic Escherichia coli (EHEC) O157:H7, derived from an outbreak in Sakai city, Japan in 1996, possesses two kinds of plasmids: a 93-kb plasmid termed pO157, found in clinical EHEC isolates world-wide and a 3.3-kb plasmid termed pOSAK1, prevalent in EHEC strains isolated in Japan. Complete nucleotide sequences of both plasmids have been determined, and the putative functions of the encoded proteins and the cis-acting DNA sequences have been analyzed. pO157 shares strikingly similar genes and DNA sequences with F-factor and the transmissible drug-resistant plasmid R100 for DNA replication, copy number control, plasmid segregation, conjugative functions and stable maintenance in the host, although it is defective in DNA transfer by conjugation due to the truncation and deletion of the required genes and DNA sequences. In addition, it encodes several proteins implicated in EHEC pathogenicity such as an EHEC hemolysin (HlyA), a catalase-peroxidase (KatP), a serine protease (EspP) and type II secretion system. pOSAK1 possesses a ColE1-like replication system, and the DNA sequence is extremely similar to that of a drug-resistant plasmid, NTP16, derived from Salmonella typhimurium except that it lacks drug resistance transposons.

Direct association of presenilin-1 with beta-catenin

Families bearing mutations in the presenilin-1 (PSI) gene develop Alzheimer's disease (AD). However, the mechanism through which PS1 causes AD is unclear. The co-immunoprecipitation with PS1 in transfected COS-7 cells indicates that PSI directly interacts with endogenous beta-catenin, and the interaction requires residues 322450 of PSI and 445-676 of beta-catenin. Both proteins are co-localized in the endoplasmic reticulum. Over-expression of PS1 reduces the level of cytoplasmic beta-catenin, and inhibits beta-catenin-T cell factor-regulated transcription. These results indicate that PSI plays a role as inhibitor of the beta-catenin signal, which may be connected with the AD dysfunction.

Endoscopic treatment of early oesophageal or gastric cancer

BACKGROUND AND AIMS

Endoscopic treatment has become increasingly popular in recent years as an alternative to surgical treatment with the hope of offering superior quality of life (QOL) for the patient. The results of endoscopic treatment of mucosal lesions of mostly early oesophageal or gastric cancer performed in 145 patients (155 lesions) over the past eight years were reviewed from the standpoint of QOL.

RESULTS

In 56 patients who underwent radical resection of the oesophageal mucosa, no serious complications and symptoms occurred, with epithelialisation completed within about a month. Patients also showed good results regarding dietary intake and performance status (PS), and all are currently alive without any sign of recurrence. One time fractionated endoscopic resection was carried out in about 40% of the 57 patients who underwent gastric mucosal resection. In these 57 patients, an artificial ulcer measuring 3 cm or more was formed, resulting in a favourable outcome after healing. An overwhelming proportion of these subjects had no symptoms and good PS after the treatment.

CONCLUSIONS

The introduction of this method, endoscopic mucosal resection using a cap fitted panendoscope, is expected to permit additional indications for endoscopic treatment. Endoscopic Nd-YAG laser irradiation was applied mainly to early gastric cancer lesions (32 patients), usually for relative indications for endoscopic treatment. This procedure is safe and advantageous in that it requires no hospitalisation, permits fractionated irradiation, and secures good QOL.

Purification and characterization of a hemolysin produced by Vibrio cholerae biotype El Tor: another toxic substance produced by cholera vibrios

A thermolabile direct hemolysin from an El Tor cholera vibrio strain has been isolated and partially characterized as a simple protein of ca. 20,000 molecular weight. In addition to its hemolytic activity, the hemolysin is cytotoxic, cardiotoxic, and rapidly lethal. In these respects it resembles the thermostable direct hemolysin/cytotoxin/cardiotoxin/lethal toxin of Vibrio parahaemolyticus and certain other bacterial hemolysins, although there are other significant differences. Because identical diseases are produced by both hemolytic and nonhemolytic cholera vibrios, the El Tor hemolysin may be presumed to be pathogenetically irrelevant. These observations raise the question of "When is a toxic substance also a toxin?"