Structure and stability of molybdenum sulfide fullerenes

MoS2 nanooctahedra are believed to be the smallest stable closed-cage structures of MoS2, i.e., the genuine inorganic fullerenes. Here a combination of experiments and density functional tight binding calculations with molecular dynamics annealing are used to elucidate the structures and electronic properties of octahedral MoS2 fullerenes. Through the use of these calculations MoS2 octahedra were found to be stable beyond nMo > 100 but with the loss of 12 sulfur atoms in the six corners. In contrast to bulk and nanotubular MoS2, which are semiconductors, the Fermi level of the nanooctahedra is situated within the band, thus making them metallic-like. A model is used for extending the calculations to much larger sizes. These model calculations show that, in agreement with experiment, the multiwall nanooctahedra are stable over a limited size range of 104-105 atoms, whereupon they are converted into multiwall MoS2 nanoparticles with a quasi-spherical shape. On the experimental side, targets of MoS2 and MoSe2 were laser-ablated and analyzed mostly through transmission electron microscopy. This analysis shows that, in qualitative agreement with the theoretical analysis, multilayer nanooctahedra of MoS2 with 1000-25 000 atoms (Mo + S) are stable. Furthermore, this and previous work show that beyond approximately 105 atoms fullerene-like structures with quasi-spherical forms and 30-100 layers become stable. Laser-ablated WS2 samples yielded much less faceted and sometimes spherically symmetric nanocages.

Phylogenetic analysis of protozoa in the rumen contents of cow based on the 18S rDNA sequences

AIMS

To examine the diversity of protozoa in the rumen contents of cow.

METHODS AND RESULTS

Protozoa that inhabit the rumen were detected by PCR using protozoan-specific primers. Libraries of protozoan rDNA sequences were constructed from rumen fluid, solid tissues and epithelium. Twenty-three clones isolated from rumen fluid fell into two genera identified as Entodinium (69.6% of clones) and Epidinium (31.4% of clones). Of the clones isolated from rumen fluid, a moderate number were unidentifiable (30.4%).

CONCLUSIONS

The predominant protozoan genus identified in the whole rumen belonged to the Entodinium group (81.1%). Protozoa were not detected in the rumen epithelium.

SIGNIFICANCE AND IMPACT OF THE STUDY

These findings suggest that rumen fluid and solid tissues contain different protozoan populations that may play specific roles in rumen function. Quantitative PCR techniques and a more specific set of phylogenetic probes that distinguish between protozoan species are needed to determine the significance of newly identified groups and to determine the distribution of identified protozoan clusters in rumen microbial communities.

Cloning and characterization of ce/8A gene from Rhizobium leguminosarum bv. trifolii 1536

AIMS

To isolate the cellulase gene from Rhizobium leguminosarum bv. trifolii 1536.

METHODS AND RESULTS

By the shot-gun method a clone (cel8A) harbouring 3.1 kb genomic DNA fragment from R. leguminosarum bv. trifolii 1536 was obtained. The cel8A gene coded 348 amino acids and it belongs to the glycosyl hydrolase family 8. The molecular mass of Cel8A protein induced from Escherichia coli DH5alpha, appeared to be 35 kDa. The optimum pH and optimum temperature was 7.0, and about 30 degrees C for its enzymatic activity respectively.

CONCLUSIONS

R. leguminosarum bv. trifolii 1536 had cel8A gene having an open reading frame of 1047 bp coded for the activity of hydrolyzation of carboxymethyl cellulose.

SIGNIFICANCE AND IMPACT OF THE STUDY

The production of celluloytic enzyme by R. leguminosarum bv. trifolii was confirmed, which would play specific roles in rhizobia. Future study should focus on its role in the infection and nodulation phenomena.

Reuse of wastewater sludge with marine clay as a new resource of construction aggregates

The disposal of sludge from wastewater treatment presents highly complex problems to any municipality. Most of the sludge disposal methods have varying degrees of environmental impact. Hence, it is necessary to explore potential areas of reuse in order to alleviate sludge disposal problems and to conserve natural resources. Industrial sludge and marine clay are two forms of high-volume wastes. Using these wastes as a resource of raw materials to produce construction aggregates would enable large-scale sludge reuse. The aggregates were produced at various sludge-clay combinations containing 0, 20, 50, 80 and 100% clay contents, respectively. The pelletized aggregates displayed lower particle densities ranged between 1.48 and 2.25 g/cm3, compared to the density of granite at 2.56 g/cm3. Good 28-day concrete compressive strength of 38.5 N/mm2 achieved by the 100% sludge aggregate was comparable to the value of 38.0 N/mm2 achieved of the granite control specimens. The leachate contamination levels from the aggregates after 150 days were found acceptable when used in concrete, indicating insignificant environmental contamination. The heat flow study showed increases in heat flow at the temperatures of 480 degrees C and between 660 degrees C and 900 degrees C, indicating a need for the extension of heating time around these temperatures.

A comparison of ultrasound treatment on primary and secondary sludges

Ultrasound treatment of primary and secondary sludges was conducted to improve the qualities of sludges for the anaerobic digestion. The impacts of different sonication times, sonication densities and solids concentrations on ultrasonication efficiency were examined. The experimental results indicated that the significant reduction in particle size and increase in soluble organics could be achieved, implying that ultrasonication could offer a feasible treatment method to efficiently disintegrate sludge. The greater decrease in particle size and increase in soluble organics of sludge indicated that the secondary sludge has a more remarkable improvement after sonication over the primary sludge. With respects to the extent of disintegration and energy consumption, higher sonication density performed more effectively in terms of specific energy. There exists an optimal solids concentration range for both the sludges for optimum sonication. Within the optimal solids concentration range, efficient sonication can be effected and sludge would be disintegrated efficiently. The ultrasound would be attenuated by scattering and absorption if the solids concentration exceeds the optimal range. It appeared from the study that the mechanical shear forces caused by ultrasonic cavitation could be a key factor for sludge disintegration and collapse of cavitation bubbles could significantly alter the sludge characteristics.

Manufacturing artificial aggregates from industrial sludge and marine clay with addition of sodium salt

The potential of converting industrial sludge and dredged marine clay into building and construction materials as an alternative to disposal was investigated in this study. The industrial sludge was mixed with marine clay at various compositions and was shaped into round pellets to be used as concrete aggregates. The pellets were then dried and transferred into a high temperature kiln where they were heated at 1,135 degrees C. The artificial aggregates were more porous then the normal granite aggregate. The occurrence of this condition was suspected to be attributed to two factors, viz. the firing temperature and the amount of sodium in the aggregates. To validate this hypothesis, the aggregates with and without added sodium chloride were fired at temperatures of 1,100 and 1, 200 degrees C. Results showed a reduction in the densities of the aggregates with the addition of sodium chloride and the increase in firing temperature.

4G/5G polymorphism of the plasminogen activator inhibitor-1 gene and insertion/deletion polymorphism of the tissue-type plasminogen activator gene in atherothrombotic stroke

BACKGROUND AND PURPOSE

Decreased fibrinolytic capacity due to increased plasminogen activator inhibitor-1 (PAI-1) activity and decreased tissue-type plasminogen activator (t-PA) activity has been associated with hypertension or atherothrombotic disorders. The aims of this study were to observe associations of the genetic polymorphism for PAI-1 and t-PA with hypertension and atherothrombotic stroke, and to elucidate whether impaired fibrinolytic activity in atherothrombotic stroke was related to atherothrombosis per se or to other risk factors such as hypertension.

METHODS

Patients with atherothrombotic stroke (n = 60), hypertension (n = 100), and control subjects (n = 100) were enrolled. We genotyped all subjects for 4G/5G polymorphism in the promoter region of the PAI-1 gene and the Alu-repeat insertion/deletion (I/D) polymorphism in intron h of the t-PA gene by polymerase chain reaction and endonuclease digestion.

RESULTS

The frequency of the 4G/4G genotype of PAI-1 was significantly higher in the atherothrombotic stroke patients than the control subjects (41.7 versus 21%; p = 0.005), but not in the hypertensive subjects. There was a significant association between 4G/4G genotype of PAI-1 and atherothrombotic stroke (adjusted odds ratio = 3.11, 95% confidence interval 1.18-8.15), adjusting for age, sex, total cholesterol, low-density lipoprotein, triglyceride, and body mass index. However, the number of the I/I genotype of t-PA in the atherothrombotic stroke or hypertensive patients was virtually identical to the control subjects.

CONCLUSION

Our results suggest that the 4G/4G genotype of the PAI-1 gene is significantly associated with an increased risk of atherothrombotic stroke. This finding also supports that impaired fibrinolytic activity in atherothrombotic stroke is related to atherothrombosis per se, but not to hypertension, one of the most important risk factors of atherothrombotic stroke.

The effect of a disrupted yhjQ gene on cellular morphology and cell growth in Escherichia coli

The 5' upstream region of the cellulose synthase operon ( bcs operon) has been isolated by cloning from Escherichia coli. A gene encoding YhjQ is located 1.0 kb upstream of the bcs operon in E. coli. The function of YhjQ remains unknown. Insertional inactivation of the yhjQ gene causes abnormal cell division, resulting in incomplete partition of the chromosome and filamentous cells of various sizes. These results suggest that the product of yhjQ may affect normal doubling and cellular morphology.

Is tumor necrosis factor genotype (TNFA2/TNFA2)a genetic prognostic factor of an unfavorable outcome in IgA nephropathy?

The purpose of this study was to examine whether there are the associations between TNF alpha and TNF beta gene polymorphisms and the development and progression of Ig A nephropathy (IgAN). A cross-sectional study on TNF alpha and TNF betagene polymorphisms by polymerase chain reaction with restriction fragment length poly-morphisms was performed on 76 patients with primary IgAN confirmed by renal biopsy and 100 healthy controls. The allele with G-->A substitution was designated as TNFA2 for the TNF alpha gene and TNFB2 for the TNF betagene. A patient in whom dialysis treatment was started or whose serum creatinine became double or over during the follow-up duration was designated as a "progressor". The TNFA2/ TNFA2 genotype was more prevalent in the progressor than in the non-pregressor group (20.0 vs 3.3%, p<0.05). Clinical factors such as serum creatinine, systolic and diastolic blood pressure (p<0.001, respectively) were higher and pathologic factor such as Grade IV or V renal lesions was more prevalent (p<0.01) in the progressor than in the non-progressor group. Therefore, TNFA2/TNFA2 genotype may be a risk factor for the progression of IgAN.

New frontiers in the continuum of dental education

During the past 150 years, dental education and training have changed from an apprenticeship to a university-based dental school. The future of dental education will be shaped by changing demographics, advances in technology, and a greater integration of science and research into the dental profession. We are entering an age of interdisciplinary practice, where dentistry provides oral health care as an integral part of an individual's overall health care.

Cloning of the cel9A gene and characterization of its gene product from marine bacterium Pseudomonas sp. SK38

The yellow-pigmented bacterial strain causing green spot rot and death of layer was isolated from Porphyra dentata. This strain has been identified as Pseudomonas sp., harboring agarase, xylanase, and protease activity, as well as carboxymethyl-cellulase (CMCase). Using genomic DNA from the Pseudomonas sp. SK38 digested with Sau3AI and ligated into pBluescript II KS+, we isolated a cel gene encoding a CMCase in Pseudomonas sp. SK38. A 4.5-kb fragment was subcloned into pKR400. The structure of the cel9A gene consists of an open reading frame of 1,521 bp starting with a GTG start codon and ending with a TAG stop codon. It thus encodes 506 amino acid residues of a protein with a calculated molecular weight of 52,636 daltons plus a signal peptide of 22 amino acids. The deduced amino acid sequence of the cel9A protein is similar to the same protein of Clostridium thermocellum. It contains, in particular, the two conserved regions of the glycoside hydrolase family 9. The apparent molecular mass of the Cel9A protein is 52 kDa as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme is most active at pH 6-7 and an optimal temperature of around 30 degrees C.

The effect of charge increase on the specificity and activity of a short antimicrobial peptide

By using short linear antimicrobial peptides as a model system, the effect of peptide charge on the specificity between Candida albicans (fungi) and Gram-positive bacteria was investigated. In a present study, we added and/or deleted lysine residue(s) at the C-terminal and/or N-terminal end(s) of an antimicrobial peptide (KKVVFKVKFK-NH(2)) and synthesized the peptides that had similar alpha helical structures in a lipid membrane mimic condition. The increase of peptide charge improved antifungal activity without the change of antibacterial activity. Structure-activity relationship study about the peptides revealed that the net positive charge must play an important role in the specificity between C. albicans and Gram-positive bacteria and the increase of the net positive charge without the moderate change of secondary structure could improve activity for C. albicans rather than Gram-positive bacteria.

Inhibition of tumor growth and metastasis by Korean mistletoe lectin is associated with apoptosis and antiangiogenesis

The mistletoe lectins are major active components in the extract of European mistletoes that have been widely used in adjuvant chemotherapy of cancer. This study was performed to investigate the mechanism of anticancer and antimetastatic activity of the purified Korean mistletoe lectin (Viscum album L. coloratum agglutinin, VCA). C57BL6 mice inoculated with B16-BL6 melanoma cells and treated with VCA were assessed for survival and metastasis. The induction of apoptosis of B16-BL6 cells by VCA was investigated by morphological changes, DNA fragmentation characteristics, and cell cycle analysis. The antiangiogenic activity of VCA was also measured by the CAM (choriallantoic membrane) assay. Length of survival of mice was increased and lung metastasis was inhibited by VCA. Treatment of cells with VCA resulted in growth suppression, nuclear morphological changes, DNA fragmentation, and an increased fraction of cells in sub-G1 consistent with apoptosis. Antiangiogenesis of VCA was assessed by CAM assay, where vessel growth induced by fat emulsion was decreased. These results suggest that VCA inhibits tumor growth and metastasis by increasing apoptosis and inhibiting angiogenesis.

Cloning and characterization of an intracellular isoamylase gene from Pectobacterium chrysanthemi PY35

The gene encoding an intracellular isoamylase from the Pectobacterium chrysanthemi PY35 was cloned in Escherichia coli DH5alpha and sequenced. The isoamylase gene (amyX) had an open reading frame of 1974 bp encoding 657 amino acid residues with a calculated molecular weight of 74,151 Da. The molecular weight of the enzyme was also estimated to be 74 kDa by activity staining of a SDS-PA gel. Isoamylase from P. chrysanthemi PY35 had 59% pairwise amino acid identity with glycogen debranching enzyme from E. coli and contained the four regions conserved among all amylolytic enzymes. The isoamylase was optimally active at pH 7 and 40 degrees C. AmyX hydrolyzed alpha-1,6-glycosidic linkages of amylopectin, while did not hydrolyze alpha-1,4-glycosidic linkages of amylose.

mRNA expression of urokinase and plasminogen activator inhibitor-1 in human crescentic glomerulonephritis

AIMS

Weak staining for urokinase-plasminogen activator (uPA), tissue type plasminogen activator (tPA), or plasminogen activator inhibitor-1 (PAI-1) confined to crescents has been described in a few cases of severe crescentic glomerulonephritis. We evaluated the molecular mechanism by which these proteins are increased or induced within crescents.

METHODS AND RESULTS

We examined uPA, tPA and PAI-1 mRNA expression in 12 renal biopsies with crescentic glomerulonephritis, and in six control renal biopsies with no detectable abnormalities by RNA in-situ hybridization. The expressions of uPA, tPA and PAI-1 proteins were also assessed by immunofluorescence. To better determine the cellular origin of uPA and PAI-1 transcripts, CD68 protein was studied by immunohistochemistry on the same sections on which in-situ hybridization had been performed. In controls, there were very low level signals of uPA and PAI-1 mRNAs in a few glomerular epithelial cells (GECs). Specific signals of uPA and PAI-1 mRNAs were detected in the cells forming crescents in all the cases with crescentic glomerulonephritis. However, weak expression of mRNA for tPA was detected in two cases only. Immunostaining for uPA and PAI-1 was positive in some but not all, cases of crescentic glomerulonephritis. A double-labelling study showed that the signal for PAI-1 and uPA mRNAs was mainly in CD68- cells.

CONCLUSIONS

Local accumulation of uPA or PAI-1 in crescents is associated with enhanced mRNA expression of these proteins. The up-regulation of PAI-1 mRNA by GECs, in particular, could play a major role in the formation of persistent fibrin deposits and progression of the lesions in crescents. Whether up-regulation of uPA is an epiphenomenon or plays a pathogenic role in the formation of crescents remains to be clarified.

Enzymatic activation of autotaxin by divalent cations without EF-hand loop region involvement

Autotaxin (ATX) is a recently described member of the nucleotide pyrophosphatase/phosphodiesterase (NPP) family of proteins with potent tumor cell motility-stimulating activity. Like other NPPs, ATX is a glycoprotein with peptide sequences homologous to the catalytic site of bovine intestinal alkaline phosphodiesterase (PDE) and the loop region of an EF-hand motif. The PDE active site of ATX has been associated with the motility-stimulating activity of ATX. In this study, we examined the roles of the EF-hand loop region and of divalent cations on the enzymatic activities of ATX. Ca(2+) or Mg(2+) was each demonstrated to increase the PDE activity of ATX in a concentration-dependent manner, whereas incubation of ATX with chelating agents abolished this activity, indicating a requirement for divalent cations. Non-linear regression analysis of enzyme kinetic data indicated that addition of these divalent cations increases reaction velocity predominantly through an effect on V(max.) Three mutant proteins, Ala(740)-, Ala(742)-, and Ala(751)-ATX, in the EF-hand loop region of ATX had enzymatic activity comparable to that of the wild-type protein. A deletion mutation of the entire loop region resulted in slightly reduced PDE activity but normal motility-stimulating activity. However, the PDE activity of this same deletion mutant remained sensitive to augmentation by cations, strongly implying that cations exert their effect by interactions outside of the EF-hand loop region.

Characterization of a novel allele of glucose oxidase from a Korean wild type strain of Aspergillus niger

We have identified a novel allele of the glucose oxidase (GO, EC1.1.3.4) gene (GO) from a Korean wild type strain of Aspergillus niger, ACMO4, with an increased GO activity in culture filtrate. Southern blot analyses of GO from ACMO4 (GO-ACMO4) revealed that the gene was present as a single copy in the genome of A. niger. However, its sequence differs from that of GO from A. niger ATCC 9029 (GO-ATCC9029). GO-ACMO4 appears to be a functional gene based on the fact that it is enzymatically active when heterologously expressed in yeast. Sequence comparisons of the coding region of GO-ACMO4 revealed 16 nucleotide changes that resulted in four amino acid substitutions; T432D, G517D, G530S, and Q542R. The GO proteins from both ATCC 9029 and ACMO4 were heterologously expressed, purified, and compared biochemically. The two enzymes showed no difference in their apparent Km value for glucose (30 mM), but the Vmax of GO-ACMO4 (515.6 unit/mg) was 10% higher than that of GO-ATCC 9029, resulting in a 10% higher specific activity.

Tactile-spatial and cross-modal attention effects in the second somatosensory and 7b cortical areas of rhesus monkeys

This study analyzed neuronal responses in the second somatosensory (SII) and 7b cortical areas during a selective attention task. Cues directed attention to one of three simultaneous stimuli: vibrotactile stimuli applied to mirror sites on both hands or to a similarly timed auditory tone. Two stimulus patterns appeared with equal probability for the cued stimulus: a constant amplitude sinewave or the latter with a superimposed brief amplitude pulse midway in the trial. Uncued stimuli always contained amplitude pulses. Monkeys demonstrated whether an amplitude pulse at the cued location was present or absent by making appropriately rewarded up and down foot pedal movements. Cue location and stimulus pattern varied trial-wise and pseudo-randomly. Average firing rates to vibrotactile stimuli in 82 of 181 SII cells and 13 of 22 area 7b cells differed significantly during at least one epoch for trials cued to the contralateral hand when compared to trials cued to the ipsilateral hand or auditory stimulus. Predominant were relatively suppressed firing rates during times prior to the epoch containing the amplitude pulses or enhanced activity during and after these pulses. Generally, different cells showed suppression early vs enhancement later in a trial. Analyses of the ratio between firing rates before and during the amplitude pulses suggested improved evoked signals to the amplitude pulses. The discussion considers attention as a mechanism for reducing distractions, early in the trial through suppressing these signals, or for selectively increasing response magnitudes in the cued channel, especially around times when amplitude pulses were present or absent.

The methylenetetrahydrofolate reductase gene polymorphism in Koreans with coronary artery disease

Hyperhomocysteinemia is a known risk factor of cardiovascular diseases. Methylenetetrahydrofolate reductase (MTHFR), involved in folate-dependant metabolism, is associated with homocysteine levels. We studied the associations among MTHFR genotypes, coronary artery disease (CAD), and homocysteine levels in 85 patients with CAD and 152 healthy subjects. The MTHFR genotypes and plasma homocysteine levels were determined. No significant difference in mutation of the MTHFR gene between two groups was observed (P>0.05). While the homozygous mutant genotype (V/V) had the highest homocysteine levels compared to wild (A/A) and heterozygous mutant (A/V) genotypes, there were no significant differences in homocysteine levels among the MTHFR genotype groups. Homocysteine was significantly and inversely related to folate levels, the significant association in V/V genotype (beta coefficient=-1.954, P=0.04). Our data suggested that MTHFR polymorphism was not associated with homocysteine levels, implying no association between gene polymorphism and CAD in Koreans.

Effects of housing relocation on immunocompetence and psychosocial functioning in older adults

BACKGROUND

The psychological and physical response to moderate life stressors among older adults has not been well characterized. This research examines effects of voluntary housing relocation on distress and immune function in healthy older adults as a model for studying the effects of moderate life stress.

METHODS

Thirty older adults moving to congregate living facilities were assessed 1 month premove, 2 weeks postmove, and 3 months postmove. Twenty-eight nonmoving control subjects were assessed at similar time points. Subjects completed psychosocial questionnaires and had early morning blood draws in their homes. Blood samples were assayed for natural killer cell cytotoxicity (NKCC), interleukin-6 (IL-6), and IgG antibody titers to the Epstein Barr virus (EBV) viral capsid antigen.

RESULTS

Movers demonstrated decreased vigor and elevated thought intrusion 1 month premove and 2 weeks postmove. By the 3-month follow-up, vigor increased, and intrusion decreased to levels commensurate with the controls. Averaged across all time points, movers showed lower NKCC than controls; however, post-hoc analyses indicate that by the 3-month follow-up time point, these differences were no longer significant. There were no differences between groups in IL-6 or in EBV antibody titers. Independent of the effects of group, higher levels of vigor were associated with greater NKCC at all assessments and with lower EBV titers at 2 weeks postmove.

CONCLUSIONS

Findings suggest that in general, healthy older adults recover well psychologically from moderate. temporary life stressors such as moving. Whereas movers showed generally lower NKCC than controls, IL-6 and EBV antibody titers appeared not to be strongly affected by the stress of moving.

Reuse of industrial sludge as construction aggregates

Industrial wastewater sludge and dredged marine clay are high volume wastes that needed enormous space at landfill disposal sites. Due to the limitation of land space, there is an urgent need for alternative disposal methods for these two wastes. This study investigates the possibility of using the industrial sludge in combination with marine clay as construction aggregates. Different proportions of sludge and clay were made into round and angular aggregates. It was found that certain mix proportions could provide aggregates of adequate strength, comparable to that of conventional aggregates. Concrete samples cast from the sludge-clay aggregates yield compressive strengths in the range of 31.0 to 39.0 N/mm2. The results showed that the round aggregates of 100% sludge and the crush aggregates of sludge with up to 20% clay produced concrete of compressive strengths which are superior to that of 38.0 N/mm2 for conventional aggregate. The study indicates that the conversion of high volume wastes into construction materials is a potential option for waste management.

The detection of p53 gene mutation using a microdissection technique in primary intracranial germ cell tumors

Using a microdissection technique, the contribution of the p53 mutation to tumorigenesis and prognosis in each histological subtype of the intracranial germ cell tumors (GCTs) was evaluated. Nineteen patients had primary intracranial GCTs, including 4 germinomas (GEs), 4 teratomas (TEs), 1 mixed tumor of GE and TE, and 10 mixed GCTs containing non-germinomatous malignant germ cell tumors (NG-MGCTs). After microdissection of specific subtypes, genomic DNA was screened for mutations in exons 5-8 of the p53 gene, using the dideoxyfingerprinting (ddF) followed by direct DNA sequencing. The direct sequencing revealed a total of six mutations in PCR products derived from the five cases (26%) which showed mobility shifts in ddF. Among the six mutations detected, four were missense mutations and two were silent. Missense mutations of the p53 gene tended to occur more frequently in the NG-MGCT component than in the GE or TE components (3/15 vs. 1/12 vs. 0/13). The incidence of missense mutations was not different between the survivors (3/13) and the deceased (1/6). This study suggests the possible role of the p53 gene in the tumori-genesis of NG-MGCT. However, p53 gene mutation did not correlate with the prognosis of NG-MGCT.

Associations between laboratory parameters and outcome of paraquat poisoning

Paraquat, a non-selective herbicide, is a known fatal substance in humans, and intentional ingestion of paraquat is increasing among Korean suicides. In 1999, 147 subjects admitted to the Institute of Pesticide Poisoning, Soonchunhyang Chunan Hospital, Korea ingested paraquat. Initial routine laboratory tests were conducted and the outcome of paraquat poisoning was categorized as survivor and fatality. Mean amount (S.D.) of ingestion was 54.5 (104.9) ml, and the overall fatality rate was 44.2%. Abnormal liver function (GOT and GPT), renal dysfunction (BUN and creatinine), metabolic acidosis (pH and PaCO(2)), and abnormal urine analysis (RBC, WBC, and protein) had significant odds ratios (ORs) for paraquat fatality (P<0.05). In multiple logistic regression, subjects with liver or renal dysfunction or metabolic acidosis had significant risks of the fatality. Our results determined that initial routine laboratory parameters could be used to predict the outcome of paraquat poisoning and recommended that evaluation of acid-base status and renal and liver function should be conducted and evaluated before intensive therapy.

Role of sea surface temperature and soil-moisture feedback in the 1998 Oklahoma-Texas drought

The drought that affected the US states of Oklahoma and Texas in the summer of 1998 was strong and persistent, with soil moisture reaching levels comparable to those of the 1930s 'dust bowl'. Although other effects of the record-strength 1997-98 El Niño were successfully predicted over much of the United States, the Oklahoma-Texas drought was not. Whereas the response of the tropical atmosphere to strong anomalies in sea surface temperature is quite predictable, the response of the extratropical atmosphere is more variable. Here we present results from mechanistic experiments to clarify the origin and maintenance of this extratropical climate extreme. In addition to global atmospheric models, we use a regional model to isolate regional climate feedbacks. We conclude that during April and May 1998, sea surface temperature anomalies combined with a favourable atmospheric circulation to establish the drought. In June-August, the regional positive feedback associated with lower evaporation and precipitation contributed substantially to the maintenance of the drought. The drought ended in the autumn, when stronger large-scale weather systems were able to penetrate the region and overwhelm the soil-moisture feedback. Our results show the potential for numerical models including appropriate physical processes to make skillful predictions of regional climate.