Prediction of variceal hemorrhage by esophageal endoscopy

To assess the risk of variceal bleeding, endoscopic findings in 172 patients with esophageal varices were classified based on the "General Rules for Recording Endoscopic Findings on Esophageal Varices" prepared by the Japanese Research Society for Portal Hypertension. Among the factor which enabled an accurate prediction of bleeding were the red wale marking and cherry-red spot of the red color sign category and blue varices of the fundamental color category with large varices. Other factors in the "General Rules" such as the form and location were of minor significance in prediction of the bleeding. Each of these factors can be quantified and an assessment can be made of the likelihood of bleeding. By calculating the total score of these factors, the risk of bleeding in individual patients was accurately estimated.

Complete genome structure of the nitrogen-fixing symbiotic bacterium Mesorhizobium loti

The complete nucleotide sequence of the genome of a symbiotic bacterium Mesorhizobium loti strain MAFF303099 was determined. The genome of M. loti consisted of a single chromosome (7,036,071 bp) and two plasmids, designated as pMLa (351,911 bp) and pMLb (208, 315 bp). The chromosome comprises 6752 potential protein-coding genes, two sets of rRNA genes and 50 tRNA genes representing 47 tRNA species. Fifty-four percent of the potential protein genes showed sequence similarity to genes of known function, 21% to hypothetical genes, and the remaining 25% had no apparent similarity to reported genes. A 611-kb DNA segment, a highly probable candidate of a symbiotic island, was identified, and 30 genes for nitrogen fixation and 24 genes for nodulation were assigned in this region. Codon usage analysis suggested that the symbiotic island as well as the plasmids originated and were transmitted from other genetic systems. The genomes of two plasmids, pMLa and pMLb, contained 320 and 209 potential protein-coding genes, respectively, for a variety of biological functions. These include genes for the ABC-transporter system, phosphate assimilation, two-component system, DNA replication and conjugation, but only one gene for nodulation was identified.

Classification and evolution of EF-hand proteins

Forty-five distinct subfamilies of EF-hand proteins have been identified. They contain from two to eight EF-hands that are recognizable by amino acid sequence as being statistically similar to other EF-hand domains. All proteins within one subfamily are congruent to one another, i.e. the dendrogram computed from one of the EF-hand domains is similar, within statistical error, to the dendrogram computed from another(s) domain. Thirteen subfamilies--including Calmodulin, Troponin C, Essential light chain, Regulatory light chain--referred to collectively as CTER, are congruent with one another. They appear to have evolved from a single ur-domain by two cycles of gene duplication and fusion. The subfamilies of CTER subsequently evolved by gene duplications and speciations. The remaining 32 subfamilies do not show such general patterns of congruence; however, some--such as S100, intestinal calcium binding protein (calbindin 9 kd), and trichohylin--do not form congruent clusters of subfamilies. Nearly all of the domains 1, 3, 5, and 7 are most similar to other ODD domains. Correspondingly the EVEN numbered domains of all 45 subfamilies most closely resemble EVEN domains of other subfamilies. Many sequence and chemical characteristics do not show systemic trends by subfamily or species of host organisms; such homoplasy is widespread. Eighteen of the subfamilies are heterochimeric; in addition to multiple EF-hands they contain domains of other evolutionary origins.

A comparison of several hypertonic solutions for resuscitation of bled sheep

Small volumes (4 ml/kg) of 2400 mOsm NaCl restore cardiac output and mean arterial pressure to 80% of baseline after hemorrhage (65% of blood volume) in unanesthetized sheep. An equal volume of normal saline is less effective. To identify an optimal hypertonic solution, we screened six 2400 mOsm solutions in 18 randomized experiments in 8 sheep: NaCl, NaHCO3, NaCl/sodium acetate, NaCl/mannitol, NaCl/6% Dextran 70, and glucose. Cardiovascular function, as determined by cardiac output and mean arterial pressure, was restored best with NaCl, NaCl/NaAc, and NaCl/Dex. These three solutions were then evaluated using 18 sheep in 36 experiments. Following a 1-hr baseline period, the sheep were bled to a mean arterial pressure of 50 mm Hg for 2 hr. One of the solutions was then given in a volume of 4 ml/kg over 2 min and the sheep were monitored for 3 hr. Within 3 min of the infusion, cardiac output increased to greater than 100% of baseline for all three solutions. The NaCl-Dex solution sustained a significantly higher cardiac output over the 3-hr observation period than the other solutions. Plasma volume increased for all solutions following infusion. NaCl-Dex maintained plasma volume significantly better than the other solutions. As a further control, an isotonic solution of 6% Dextran 70 in normal saline was studied. It was not as effective as the hypertonic NaCl-Dex in maintaining cardiac output, mean arterial pressure, or plasma volume. Osmolality increased 10% (309 to 326 mOsm/kg H2O), plasma [NA] increased 7% (151 to 161 meq/liter), and plasma [K] decreased from 3.9 to 2.6 meq/liter following the hypertonic infusions. The sheep appeared to tolerate these electrolyte changes well. We conclude that a single bolus infusion of 2400 mOsm NaCl with 6% Dextran 70 best resuscitates sheep that have been subjected to a moderate degree of hemorrhagic shock compared to several other solutions. Its beneficial effects are caused in part by a sustained reestablishment of plasma volume. More studies are needed to document the safety of dextran in the clinical setting of hemorrhagic shock. Small volumes of hypertonic solutions may be valuable in the initial fluid resuscitation of patients in hemorrhagic shock.

C-reactive protein is protective against Streptococcus pneumoniae infection in mice

C-reactive protein (CRP) has several properties that suggest that it may function as a bacterial opsonin. CRP shows binding reactivity with pneumococcal C-polysaccharide, the cell wall carbohydrate of Streptococcus pneumoniae. In this study we have demonstrated protection of mice against serotypes 3 and 4 of S. pneumoniae infection by a single prior injection of CRP. This effect was seen both in mice that lacked antibody to phosphocholine and in normal mice. Thus the opsonic properties of CRP previously described may be related to protection against pneumococcal infection.

Simultaneous or delayed administration of hepatocyte growth factor equally represses the fibrotic changes in murine lung injury induced by bleomycin. A morphologic study

Hepatocyte growth factor (HGF) is a humoral mediator of epithelial-mesenchymal interactions, acting on a variety of epithelial cells as mitogen, motogen, and morphogen. Exogenous HGF acts as a hepatotrophic factor and a renotrophic factor during experimental injury. To investigate whether HGF has a pulmotrophic function, human recombinant HGF was administered to C57BL/6 mice with severe lung injury by bleomycin (BLM). Low dose simultaneous and continuous administration of HGF (50 micrograms/mouse/7 d) with BLM (100 mg/mouse/7 d) repressed fibrotic morphological changes at 2 and 4 wk. Ashcroft score showed a significant difference in lung fibrosis with and without HGF at 4 wk (3.7 +/- 0.4 versus 4.9 +/- 0.3, p < 0.05). Furthermore, either simultaneous or delayed administration of high dose HGF (280 micrograms/mouse/14 d) equally repressed fibrotic changes by BLM when examined at 4 wk (Ashcroft score: 2.6 +/- 0.4 and 2.4 +/- 0.2 versus 4.1 +/- 0.2, p < 0.01). Hydroxyproline content in the lungs was significantly lower in mice with either simultaneous or delayed administration of high dose HGF as compared to those administered BLM alone (121.8 +/- 8.1% and 113.2 +/- 6.2% versus 162.7 +/- 4.6%, p < 0.001). These findings indicate that exogenous HGF acts as a pulmotrophic factor in vivo and prevents the progression of BLM-induced lung injury when administered in either a simultaneous or delayed fashion. HGF may be a potent candidate to prevent or treat lung fibrosis.

Evolution of EF-hand calcium-modulated proteins. II. Domains of several subfamilies have diverse evolutionary histories

In the first report in this series we described the relationships and evolution of 152 individual proteins of the EF-hand subfamilies. Here we add 66 additional proteins and define eight (CDC, TPNV, CLNB, LPS, DGK, 1F8, VIS, TCBP) new subfamilies and seven (CAL, SQUD, CDPK, EFH5, TPP, LAV, CRGP) new unique proteins, which we assume represent new subfamilies. The main focus of this study is the classification of individual EF-hand domains. Five subfamilies--calmodulin, troponin C, essential light chain, regulatory light chain, CDC31/caltractin--and three uniques--call, squidulin, and calcium-dependent protein kinase--are congruent in that all evolved from a common four-domain precursor. In contrast calpain and sarcoplasmic calcium-binding protein (SARC) each evolved from its own one-domain precursor. The remaining 19 subfamilies and uniques appear to have evolved by translocation and splicing of genes encoding the EF-hand domains that were precursors to the congruent eight and to calpain and to SARC. The rates of evolution of the EF-hand domains are slower following formation of the subfamilies and establishment of their functions. Subfamilies are not readily classified by patterns of calcium coordination, interdomain linker stability, and glycine and proline distribution. There are many homoplasies indicating that similar variants of the EF-hand evolved by independent pathways.

Involvement of cpxA, a sensor of a two-component regulatory system, in the pH-dependent regulation of expression of Shigella sonnei virF gene

In Shigella species, IpaBCD proteins encoded on the virulence plasmid direct the entry of this bacterium into host epithelial cells. Expression of the ipaBCD genes is under the control of several environmental conditions, such as temperature and osmolarity. Extracellular pH also controlled the the expression of the genes, and this regulation occurred mainly at the step of expression of virF, a plasmid-encoded positive regulator of ipaBCD. The expression of virF was activated at high pH (pH 7.4) and repressed at low pH (pH 6.0). We isolated a Tn10 transposon mutant in Escherichia coli K-12 which altered this regulation at the transcriptional level. The Tn10 in the mutant inserted within a reading frame of the cpxA gene, whose product belongs to a family of sensor proteins of two-component signal transduction systems. Complementation analysis showed that cpxA was involved in the pH-dependent regulation of virF gene expression. A gene homologous to cpxA was conserved in Shigella spp. as well as in E. coli. These results may indicate that CpxA senses directly or indirectly a change in extracellular pH and influences the expression of virF in E. coli and Shigella spp.

Role of nitric oxide in learning and memory and in monoamine metabolism in the rat brain

1. We investigated the effects of NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthase, on the performance of rats in a radial arm maze and in habituation tasks, and on monoamine metabolism in the brain. 2. Daily administration of L-NAME (10-60 mg kg-1) resulted in a dose-dependent impairment of performance during the acquisition of the radial arm maze task, while it failed to affect performance in those rats that had previously acquired the task. 3. The rate of decrease in locomotor activity in the habituation task in the L-NAME-treated rats was significantly less than that in control rats. 4. NG-nitro-D-arginine methyl ester (D-NAME, a less active inhibitor of NO synthase) showed no effects in the above behavioural tasks. 5. NO synthase activity was significantly decreased in both the L-NAME and D-NAME-treated rats, with the magnitude of inhibition being greater in the L-NAME-treated animals. 6. The content of 5-hydroxyindoleacetic acid (5-HIAA) in the hippocampus and the 5-HIAA/5-hydroxytryptamine ratio in the hippocampus and cortex were significantly decreased in the L-NAME (60 mg kg-1)-treated rats compared with these values in the controls. 7. Striatal 3,4-dihydroxyphenylacetic acid (DOPAC) content was significantly increased in the L-NAME (60 mg kg-1)-treated rats compared with the values in the controls, while the DOPAC/dopamine ratio was not changed. 8. These results suggest that: (i) NO may play an important role in performance during the acquisition,but not retention, of the radial arm maze task, and (ii) that endogenous NO may be involved in the regulation of monoamine metabolism.

Sequence and analysis of chromosome 5 of the plant Arabidopsis thaliana

The genome of the model plant Arabidopsis thaliana has been sequenced by an international collaboration, The Arabidopsis Genome Initiative. Here we report the complete sequence of chromosome 5. This chromosome is 26 megabases long; it is the second largest Arabidopsis chromosome and represents 21% of the sequenced regions of the genome. The sequence of chromosomes 2 and 4 have been reported previously and that of chromosomes 1 and 3, together with an analysis of the complete genome sequence, are reported in this issue. Analysis of the sequence of chromosome 5 yields further insights into centromere structure and the sequence determinants of heterochromatin condensation. The 5,874 genes encoded on chromosome 5 reveal several new functions in plants, and the patterns of gene organization provide insights into the mechanisms and extent of genome evolution in plants.

Sequence and analysis of chromosome 3 of the plant Arabidopsis thaliana

Arabidopsis thaliana is an important model system for plant biologists. In 1996 an international collaboration (the Arabidopsis Genome Initiative) was formed to sequence the whole genome of Arabidopsis and in 1999 the sequence of the first two chromosomes was reported. The sequence of the last three chromosomes and an analysis of the whole genome are reported in this issue. Here we present the sequence of chromosome 3, organized into four sequence segments (contigs). The two largest (13.5 and 9.2 Mb) correspond to the top (long) and the bottom (short) arms of chromosome 3, and the two small contigs are located in the genetically defined centromere. This chromosome encodes 5,220 of the roughly 25,500 predicted protein-coding genes in the genome. About 20% of the predicted proteins have significant homology to proteins in eukaryotic genomes for which the complete sequence is available, pointing to important conserved cellular functions among eukaryotes.

Infusion of very hypertonic saline to bled rats: membrane potentials and fluid shifts

Anesthetized rats were subjected to a moderate degree of hemorrhagic shock, lowering their mean arterial pressure to approximately 50 mm Hg for approximately 100 min. At the end of the shock period, resting skeletal muscle transmembrane potentials had depolarized from a baseline value of -82 mV to -65 mV; intracellular water had increased by 13%; and intracellular sodium and chloride contents had doubled. Eight rats were then given an infusion of very hypertonic saline (2400 mOsmole/kg, calculated osmolality) in a volume equal to only 10% of the volume of shed blood; another eight rats were given the equivalent amount of sodium and chloride in an isotonic solution (volume equal to 80% of shed blood). The mean arterial pressure in the rats that were given the very hypertonic saline returned to 81 mm Hg, compared to 55 mm Hg in the animals given normal saline. The membrane potentials in the hypertonic group polarized back to near normal- -78 mv--compared to no changes in the normal saline group. Intracellular water returned to preshock values in the hypertonic group as did intracellular sodium and chloride contents. Cellular contents in the normal saline group remained at shock levels. It was concluded that, in rats, infusion of small amounts of hypertonic saline can reverse some of the cellular abnormalities induced by hemorrhagic shock.

Treatment of myasthenia gravis by immunoadsorption of plasma

We treated 16 patients with moderately severe to severe generalized myasthenia gravis (MG) by immunoadsorption (perfusion through a resin that adsorbs proteins) of 2,500 ml plasma on each of four alternate days. Fourteen patients who completed treatment all had significant improvement in strength (6 excellent, 6 good, and 2 fair), which began a mean of 42 hours after the first immunoadsorption, reached a maximum 4 days after the fourth immunoadsorption (mean, 250% of baseline strength), and returned to baseline over a mean of 2 months. Thirty-seven grams of plasma proteins were removed during each immunoadsorption, which required no replacement, compared with 175 grams during plasma exchange, which requires replacement with albumin. Serum or plasma concentration of all proteins fell, more so for most of the larger proteins than for the smaller ones: acetylcholine receptor antibody (AChR Ab) fell to a mean of 23% of original level, fibrinogen to 26%, C4 to 29%, IgM to 33%, IgG to 35%, CH50 to 41%, C3 to 42%, IgA to 54%, and albumin to 76%. All proteins, including AChR Ab, returned to their original levels within 1 to 3 weeks after the last immunoadsorption, while improvement in strength lasted a mean of 6 weeks longer. One seronegative patient had excellent improvement lasting more than a month. Activated complement C5a and white blood cell count rose during each immunoadsorption, while activated complement C3a fell, and each returned to its original level within hours. Eight patients had transient symptomatic hypotension attributable to withdrawal of blood more rapidly than it was returned; this hypotension was prevented or ameliorated by intravenous saline.(ABSTRACT TRUNCATED AT 250 WORDS)

The Y chromosome in the liverwort Marchantia polymorpha has accumulated unique repeat sequences harboring a male-specific gene

The haploid liverwort Marchantia polymorpha has heteromorphic sex chromosomes, an X chromosome in the female and a Y chromosome in the male. We here report on the repetitive structure of the liverwort Y chromosome through the analysis of male-specific P1-derived artificial chromosome (PAC) clones, pMM4G7 and pMM23-130F12. Several chromosome-specific sequence elements of approximately 70 to 400 nt are combined into larger arrangements, which in turn are assembled into extensive Y chromosome-specific stretches. These repeat sequences contribute 2-3 Mb to the Y chromosome based on the observations of three different approaches: fluorescence in situ hybridization, dot blot hybridization, and the frequency of clones containing the repeat sequences in the genomic library. A novel Y chromosome-specific gene family was found embedded among these repeat sequences. This gene family encodes a putative protein with a RING finger motif and is expressed specifically in male sexual organs. To our knowledge, there have been no other reports for an active Y chromosome-specific gene in plants. The chromosome-specific repeat sequences possibly contribute to determining the identity of the Y chromosome in M. polymorpha as well as to maintaining genes required for male functions, as in mammals such as human.

Effect of cilostazol, a phosphodiesterase III inhibitor, on experimental thrombosis in the porcine carotid artery

Thrombus formation in the carotid artery is one of the common causes of transient ischemic attacks and stroke. Platelet aggregation seems to be an essential component in these processes. The present study was conducted to determine the ability of cilostazol, a phosphodiesterase III inhibitor, to prevent formation of totally occlusive thrombus in a porcine carotid artery, in comparison with ticlopidine. Castrated male Yorkshire pigs were allocated to control (n=8), cilostazol (30 mg/kg, twice a day [b.i.d] for 2 days, n=8), and ticlopidine (50 mg/kg, b.i.d. for 3 days, n=7) groups. The endothelium of the right common carotid artery was injured with electrical stimulation (150 microA) without constriction and blood flow in this region was monitored by Doppler flow probe. Arterial blood was sampled during electrical stimulation for the measurement of platelet aggregation. Total occlusion rates within 240 minutes were 87.5% (7:8), 37.5% (3:8), and 85.7% (6:7) in the control, cilostazol, and ticlopidine groups, respectively. Compared with the control group, the time to total occlusion was significantly prolonged in the cilostazol group, but not in the ticlopidine group. Consistently, platelet aggregation was significantly inhibited only in the cilostazol group. Because ticlopidine increases blood flow in the intact carotid artery before injury to a greater extent than cilostazol, direct antiplatelet action is thought to be responsible for cilostazol's beneficial effect in preventing thrombotic occlusion. These results suggest that cilostazol may be useful for the inhibition of the thrombus formation in the carotid artery and for the prevention of cerebral ischemic events.

Differing effects of clarithromycin and azithromycin on cytokine production by murine dendritic cells

Summary The macrolide antibiotics are now well known to have anti-inflammatory effects. Because dendritic cells (DCs) orchestrate immune responses, we examined the in vitro effects of clarithromycin (CAM), azithromycin (AZM) and midecamycin (MDM) on the expression of co-stimulatory molecules and production of cytokines [interleukin (IL)-10, IL-6, interferon (IFN)-gamma, IL-12p40, tumour necrosis factor (TNF)-alpha] of murine bone marrow-derived DCs by lipopolysaccharide (LPS) stimulation. A 15-membered macrolide, AZM, and a 14-membered macrolide, CAM, significantly enhanced the intensity of a co-stimulatory molecule, CD80, on DCs but not CD86 and CD40. AZM significantly increased the production of IL-10 and CAM significantly inhibited the production of IL-6 by DCs. However, a 16-membered macrolide, MDM, did not have any significant effect on these surface markers and cytokine productions. Moreover, AZM increased IL-10 and CAM decreased IL-2 productions significantly, when naive T cells derived from spleen were co-cultured with DCs treated in advance with LPS and these macrolides. These findings suggest that 14-membered and 15-membered, but not 16-membered macrolides play as anti-inflammatory agents, at least in part, through modulating the functions of DCs. However, each macrolide affects them in different ways.

Two hydrophobic subunits are essential for the heme b ligation and functional assembly of complex II (succinate-ubiquinone oxidoreductase) from Escherichia coli

Complex II (succinate-ubiquinone oxidoreductase) from Escherichia coli is composed of four nonidentical subunits encoded by the sdhCDAB operon. Gene products of sdhC and sdhD are small hydrophobic subunits that anchor the hydrophilic catalytic subunits (flavoprotein and iron-sulfur protein) to the cytoplasmic membrane and are believed to be the components of cytochrome b556 in E. coli complex II. In the present study, to elucidate the role of two hydrophobic subunits in the heme b ligation and functional assembly of complex II, plasmids carrying portions of the sdh gene were constructed and introduced into E. coli MK3, which lacks succinate dehydrogenase and fumarate reductase activities. The expression of polypeptides with molecular masses of about 19 and 17 kDa was observed when sdhC and sdhD were introduced into MK3, respectively, indicating that sdhC encodes the large subunit (cybL) and sdhD the small subunit (cybS) of cytochrome b556. An increase in cytochrome b content was found in the membrane when sdhD was introduced, while the cytochrome b content did not change when sdhC was introduced. However, the cytochrome b expressed by the plasmid carrying sdhD differed from cytochrome b556 in its CO reactivity and red shift of the alpha absorption peak to 557.5 nm at 77 K. Neither hydrophobic subunit was able to bind the catalytic portion to the membrane, and only succinate dehydrogenase activity, not succinate-ubiquinone oxidoreductase activity, was found in the cytoplasmic fractions of the cells. In contrast, significantly higher amounts of cytochrome b556 were expressed in the membrane when sdhC and sdhD genes were both present, and the catalytic portion was found to be localized in the membrane with succinate-ubiquitnone oxidoreductase and succinate oxidase activities. These results strongly suggest that both hydrophobic subunits are required for heme insertion into cytochrome b556 and are essential for the functional assembly of E. coli complex II in the membrane. Accumulation of the catalytic portion in the cytoplasm was found when sdhCDAB was introduced into a heme synthesis mutant, suggesting the importance of heme in the assembly of E. coli complex II.

The E-cadherin gene is silenced by CpG methylation in human oral squamous cell carcinomas

Reduction of E-cadherin strongly relates to invasiveness and metastasis in vitro. To clarify CpG methylation around the promoter region of the E-cadherin gene in oral squamous cell carcinoma (SCC), we examined the DNA samples of various human SCC cell lines and primary oral SCC tissues by methylation-specific polymerase chain reaction (MSP). CpG methylation of the E-cadherin gene markedly correlated to the reduction of E-cadherin expression in human oral SCC cell lines. In primary oral SCC tissues, only 1 of 5 preserved E-cadherin-expressing tissues was methylated, whereas methylation was found in 17 (94.4%) of 18 E-cadherin-reduced tissues. Our results suggest that reduction of E-cadherin expression is associated with CpG methylation of the E-cadherin gene promoter. We recently established two cell lines with high and low metastatic potential, UM1 and UM2, from SCC primary tongue tissue of a patient. E-cadherin expression of high-metastatic UM1 was clearly lower than that of low-metastatic UM2, and MSP results showed CpG methylation in the UM1 but not the UM2 cell line. To investigate whether demethylation of CpG methylation of the E-cadherin gene could restore expression and function of E-cadherin, we treated UM1 with the demethylating agent 5-azacytidine (5-aza) and found that E-cadherin expression was indeed restored by demethylation. Moreover, in the demethylated UM1, invasion of the collagen gel was clearly suppressed compared with the untreated UM1. These results suggested that inactivation of E-cadherin expression resulted from CpG methylation of the gene promoter; a correlation between CpG methylation of the E-cadherin gene promoter and invasive potential was also suggested.

Indication of electron neutrino appearance from an accelerator-produced off-axis muon neutrino beam

The T2K experiment observes indications of ν(μ) → ν(e) appearance in data accumulated with 1.43×10(20) protons on target. Six events pass all selection criteria at the far detector. In a three-flavor neutrino oscillation scenario with |Δm(23)(2)| = 2.4×10(-3)  eV(2), sin(2)2θ(23) = 1 and sin(2)2θ(13) = 0, the expected number of such events is 1.5±0.3(syst). Under this hypothesis, the probability to observe six or more candidate events is 7×10(-3), equivalent to 2.5σ significance. At 90% C.L., the data are consistent with 0.03(0.04) < sin(2)2θ(13) < 0.28(0.34) for δ(CP) = 0 and a normal (inverted) hierarchy.