Characterization of theL-Lysine Biosynthetic Pathway in the Obligate MethylotrophMethylophilus methylotrophus

The L-lysine biosynthetic pathway of the gram-negative obligate methylotroph Methylophilus methylotrophus AS1 was examined through characterization of the enzymes aspartokinase (AK), aspartsemialdehyde dehydrogenase, dihydrodipicolinate synthase (DDPS), dihydrodipicolinate reductase, and diaminopimelate decarboxylase. The AK was inhibited by L-threonine and by a combination of L-threonine and L-lysine, but not by L-lysine alone, and the activity of DDPS was moderately reduced by L-lysine. In an L-lysine producing mutant (G49), isolated as an S-(2-aminoethyl)-L-cysteine (lysine analog) resistant strain, both AK and DDPS were partially resistant to feedback inhibition. The ask and dapA genes encoding AK and DDPS respectively were isolated from the parental strain, AS1, and its G49 derivative. Comparison of the sequences revealed a point mutation in each of these genes in G49. The mutation in the ask gene altered aspartic acid in a key region involved in the allosteric regulation common to AKs, while a novel mutation in the dapA gene altered tyrosine-106, which was assumed to be involved in the binding of L-lysine to DDPS.

Effects ofxapAandguaADisruption on Inosine Accumulation inEscherichia coli

A xapA-disrupted mutant was studied to minimize hypoxanthine production and to improve inosine productivity in mutants of Escherichia coli. The xapA-disrupted mutant accumulated 5.6 g/l of inosine from 40 g/l of glucose, while the parent strain accumulated 4.6 g/l. This result indicates that xapA is activated in xapA-positive inosine-producers and that xapA disruption might be useful for improving inosine productivity.

Total abdominal hysterectomy versus laparoscopically-assisted vaginal hysterectomy versus total vaginal hysterectomy

INTRODUCTION

While total abdominal hysterectomy (TAH) and total vaginal hysterectomy (TVH) are conventional procedures, we have actively introduced laparoscopically-assisted vaginal hysterectomy (LAVH) since its advent. This study was the first attempt to retrospectively compare the surgical results, including invasiveness, among the three methods of performing a hysterectomy.

METHODS

The subjects included 1181 patients who underwent total hysterectomies (TAH, n=465; LAVH, n=629; TVH, n=87) due to uterine fibroids or uterine adenomyosis at our hospital between January 1995 and December 2009. The mean age, parity, weight of the removed uterus, operative time, blood loss, rates of intra- and post-operative complications, length of post-operative hospital stay, leukocyte count, and CRP and hemoglobin levels were compared.

RESULTS

The operative time was significantly longer in the LAVH group than the other two groups. Blood loss was significantly greater in the TAH group than the LAVH and TVA groups. The rates of intra- and post-operative complications were significantly higher in the TAH group than the LAVH group. The CRP level and leukocyte count were significantly lower in the LAVH group than the TAH and TVH groups.

CONCLUSION

LAVH can be applied to nulligravidas or patients with relatively large uteri and it is proved less invasive than TAH and TVH in this study. We recommend active application of LAVH.

Effect of amplification of desensitized purF and prs on inosine accumulation in Escherichia coli

The effect of a phosphoribosylpyrophosphate (PRPP) synthetase gene (prs) that was desensitized to feedback inhibition by ADP on inosine accumulation was investigated using an inosine-producing mutant of Escherichia coli. At the same time, various types of plasmid having a PRPP amidotransferase gene (purF) that was desensitized to feedback inhibition by AMP and GMP were also investigated to improve inosine productivity using a compatible plasmid containing prs with a plasmid containing purF. The recombinant E. coli I-9 harboring a low-copy-number plasmid having the desensitized-purF (pMWKQ) accumulated 3.6 g/l inosine from 40 g/l glucose in a 2-d culture. Furthermore, desensitized-prs amplification, in addition to purF, resulted in the accumulation of 6.2 g/l inosine. Additionally, through these experiments, a spontaneous mutant with an enhanced inosine-producing ability compared with the parent strain I-9 was obtained. The spontaneous mutant I-9m harboring only pMWKQ and I-9m harboring both pMWKQ and pSTVDA (a plasmid having the desensitized-prs) accumulated 6.7 g/l and 7.5 g/l inosine, respectively, from 40 g/l glucose in a 3-d culture.

l-Lysine biosynthetic pathway of Methylophilus methylotrophus and construction of an l-lysine producer

Previously, we showed that the enzymes aspartokinase (AK) and dihydrodipicolinate synthase (DDPS), which are involved in L-lysine biosynthesis in the Gram-negative obligate methylotroph Methylophilus methylotrophus AS1, were inhibited by allosteric effectors, including L-lysine. To elucidate further the regulation of L-lysine biosynthesis in M. methylotrophus, we cloned the genes encoding three other enzymes involved in this pathway, L-aspartate-beta-semialdehyde dehydrogenase, dihydrodipicolinate reductase (DDPR) and diaminopimelate decarboxylase, and examined their properties. DDPR was markedly inhibited by L-lysine. Based on this and our previous results, we constructed an L-lysine-producing strain of M. methylotrophus by introducing well-characterized genes encoding desensitized forms of AK and DDPS, as well as dapB (encoding DDPR) from Escherichia coli, using a broad host range plasmid. L-Lysine production was significantly increased by employing an S-(2-aminoethyl)-L-cysteine (L-lysine analog)-resistant mutant as the host. This derivative accumulated L-lysine at a concentration of 1 g l(-1) of medium using methanol as a carbon source.

Effects of edd and pgi disruptions on inosine accumulation in Escherichia coli

Using an inosine-producing mutant of Escherichia coli, the contributions of the central carbon metabolism for overproducing inosine were investigated. Sodium gluconate instead of glucose was tested as a carbon source to increase the supply of ribose-5-phosphate through the oxidative pentose phosphate pathway. The edd (6-phosphogluconate dehydrase gene)-disrupted mutant accumulated 2.5 g/l of inosine from 48 g/l of sodium gluconate, compared with 1.4 g/l of inosine in the edd wild strain. The rpe (ribulose phosphate 3-epimerase gene)-disrupted mutant resulted in low cell growth and low inosine production on glucose and on gluconate. The disruption of pgi (glucose-6-phosphate isomerase gene) was effective for increasing the accumulation of inosine from glucose but resulted in low cell growth. The pgi-disrupted mutant accumulated 3.7 g/l of inosine from 40 g/l of glucose when 8 g/l of yeast extract was added to the medium. Furthermore, to improve effective utilization of adenine, the yicP (adenine deaminase gene)-disrupted mutant was evaluated. It showed higher inosine accumulation, of 3.7 g/l, than that of 2.8 g/l in the yicP wild strain when 4 g/l of yeast extract was added to the medium.

Ultrastructure and function of dimeric, soluble intercellular adhesion molecule-1 (ICAM-1)

Previous studies have demonstrated dimerization of intercellular adhesion molecule-1 (ICAM-1) on the cell surface and suggested a role for immunoglobulin superfamily domain 5 and/or the transmembrane domain in mediating such dimerization. Crystallization studies suggest that domain 1 may also mediate dimerization. ICAM-1 binds through domain 1 to the I domain of the integrin alpha(L)beta(2) (lymphocyte function-associated antigen 1). Soluble C-terminally dimerized ICAM-1 was made by replacing the transmembrane and cytoplasmic domains with an alpha-helical coiled coil. Electron microscopy revealed C-terminal dimers that were straight, slightly bent, and sometimes U-shaped. A small number of apparently closed ring-like dimers and W-shaped tetramers were found. To capture ICAM-1 dimerized at the crystallographically defined dimer interface in domain 1, cysteines were introduced into this interface. Several of these mutations resulted in the formation of soluble disulfide-bonded ICAM-1 dimers (domain 1 dimers). Combining a domain 1 cysteine mutation with the C-terminal dimers (domain 1/C-terminal dimers) resulted in significant amounts of both closed ring-like dimers and W-shaped tetramers. Surface plasmon resonance studies showed that all of the dimeric forms of ICAM-1 (domain 1, C-terminal, and domain 1/C-terminal dimers) bound similarly to the integrin alpha(L)beta(2) I domain, with affinities approximately 1.5--3-fold greater than that of monomeric ICAM-1. These studies demonstrate that ICAM-1 can form at least three different topologies and that dimerization at domain 1 does not interfere with binding in domain 1 to alpha(L)beta(2).

NF-kappa B decoy suppresses cytokine expression and thermal hyperalgesia in a rat neuropathic pain model

Pro-inflammatory cytokines have been shown to be involved in the genesis, persistence, and severity of neuropathic pain following nerve injury. The transcription factor, nuclear factor-kappa B (NF-kappaB), plays a pivotal role in regulating pro-inflammatory cytokine gene expression. To elucidate the role of NF-kappaB in the pathogenesis of neuropathic pain, using a gene-based approach of NF-kappaB decoy, we tested whether the activated NF-kappaB affected pain behavior via the expression of inflammatory mediators. Single endoneurial injections of NF-kappaB decoy, at the site of nerve lesion, significantly alleviated thermal hyperalgesia for up to 2 weeks and suppressed the expression of mRNA of the inflammatory cytokines, iNOS, and adhesion molecules at the site of nerve injury. This finding suggests that a perineural inflammatory cascade, that involves NF-kappaB, is involved in the pathogenesis of neuropathic pain.

Dimerization and the effectiveness of ICAM-1 in mediating LFA-1-dependent adhesion

Dimeric intercellular adhesion molecule-1 (ICAM-1) binds more efficiently to lymphocyte function-associated antigen-1 (LFA-1) than monomeric ICAM-1. However, it is unknown whether dimerization enhances binding simply by providing two ligand-binding sites and thereby increasing avidity, or whether it serves to generate a single "fully competent" LFA-1-binding surface. Domain 1 of ICAM-1 contains both the binding site for LFA-1, centered on residue E34, and a homodimerization interface. Whether the LFA-1-binding site extends across the homodimerization interface has not been tested. To address this question, we constructed four different heterodimeric soluble forms of ICAM-1 joined at the C terminus via an alpha-helical coiled coil (ACID-BASE). These heterodimeric ICAM-1 constructs include, (i) E34/E34 (two intact LFA-1-binding sites), (ii) E34/K34 (one disrupted LFA-1-binding site), (iii) E34/DeltaD1-2 (one deleted LFA-1-binding site), and (iv) K34/K34 (two disrupted LFA-1-binding sites). Cells bearing activated LFA-1 bound similarly to surfaces coated with either E34/K34 or E34/DeltaD1-2 and with an approximately 2-fold reduction in efficiency compared with E34/E34, suggesting that D1 dimerization, which is precluded in E34/DeltaD1-D2, is not necessary for optimal LFA-1 binding. Furthermore, BIAcore (BIAcore, Piscataway, NJ) affinity measurements revealed that soluble open LFA-1 I domain bound to immobilized soluble ICAM-1, E34/E34, E34/K34, and E34/DeltaD1-D2 with nearly identical affinities. These studies demonstrate that a single ICAM-1 monomer, not dimeric ICAM-1, represents the complete, "fully competent" LFA-1-binding surface.

Reversibly locking a protein fold in an active conformation with a disulfide bond: integrin alphaL I domains with high affinity and antagonist activity in vivo

The integrin alphaLbeta2 has three different domains in its headpiece that have been suggested to either bind ligand or to regulate ligand binding. One of these, the inserted or I domain, has a fold similar to that of small G proteins. The I domain of the alphaM and alpha2 subunits has been crystallized in both open and closed conformations; however, the alphaL I domain has been crystallized in only the closed conformation. We hypothesized that the alphaL domain also would have an open conformation, and that this would be the ligand binding conformation. Therefore, we introduced pairs of cysteine residues to form disulfides that would lock the alphaL I domain in either the open or closed conformation. Locking the I domain open resulted in a 9,000-fold increase in affinity to intercellular adhesion molecule-1 (ICAM-1), which was reversed by disulfide reduction. By contrast, the affinity of the locked closed conformer was similar to wild type. Binding completely depended on Mg(2+). Orders of affinity were ICAM-1 > ICAM-2 > ICAM-3. The k(on), k(off), and K(D) values for the locked open I domain were within 1.5-fold of values previously determined for the alphaLbeta2 complex, showing that the I domain is sufficient for full affinity binding to ICAM-1. The locked open I domain antagonized alphaLbeta2-dependent adhesion in vitro, lymphocyte homing in vivo, and firm adhesion but not rolling on high endothelial venules. The ability to reversibly lock a protein fold in an active conformation with dramatically increased affinity opens vistas in therapeutics and proteomics.

Adenine deaminase activity of the yicP gene product of Escherichia coli

During previous work on deriving inosine-producing mutants of Escherichia coli, we observed that an excess of adenine added to the culture medium was quickly converted to hypoxanthine. This phenomenon was still apparent after disruption of the known adenosine deaminase gene (add) on the E. coli chromosome, suggesting that, like Bacillus subtilis, E. coli has an adenine deaminase. As the yicP gene of E. coli shares about 35% identity with the B. subtilis adenine deaminase gene (ade), we cloned yicP from the E. coli genome and developed a strain that overexpressed its product. The enzyme was purified from a cell extract of E. coli harboring a plasmid containing the cloned yicP gene, and had significant adenine deaminase [EC 3.5.4.2] activity. It was deduced to be a homodimer, each subunit having a molecular mass of 60 kDa. The enzyme required manganese ions as a cofactor, and adenine was its only substrate. Its optimum pH was 6.5-7.0 and its optimum temperature was 60 degrees C. The apparent Km for adenine was 0.8 mM.

Glucocorticoid suppresses neutrophil activation in ventilator-induced lung injury

OBJECTIVE

To investigate, in a rat model, the role of the Mac-1/ICAM-1 pathway and the anti-inflammatory activity of steroid in ventilator-induced lung injury.

DESIGN

Prospective, randomized controlled study.

SETTING

Animal investigation using Wistar rats.

INTERVENTION

Rats in three randomly assigned groups of 18, a total of 54 animals, were subject to the following: Two groups received high peak inspiratory pressure (35 cm H2O) ventilation after pretreatment with methylprednisolone (high-methylprednisolone group) or pretreatment with methylprednisolone vehicle (high-vehicle group). The third group of animals received low peak inspiratory pressure (7 cm H2O) ventilation after pretreatment with methylprednisolone vehicle (low-vehicle group). Except for animals previously killed to establish baseline values, after 40 mins of mechanical ventilation, the animals in each group were killed. Some animals provided histological samples, and the rest received total lung lavage.

MEASUREMENT

We measured flow cytometry of lavage fluid, cell counts of tissue samples, and pressure-volume curves before and after mechanical ventilation.

RESULTS

In the groups that received high peak inspiratory pressure ventilation, both the number of neutrophils that infiltrated the lungs and the expression of Mac-1 and ICAM-1 on neutrophils and macrophages increased significantly more than in the low-vehicle group. Static lung compliance was reduced in the high peak inspiratory pressure groups. In the high peak inspiratory pressure groups, there were significantly fewer neutrophils in samples from the high-methylprednisolone group (0.412 +/- 0.1 x 10(5)) than from the high-vehicle group (1.10 +/- 0.1 x 10(5); p < .05). The high-vehicle group showed greater expression of CD11b on neutrophils, but this was significantly decreased by methylprednisolone (mean fluorescence intensity: high-vehicle, 118.4 +/- 34.3; high-methylprednisolone, 25.8 +/- 4.2; p < .05). The lung mechanics measured by pressure-volume curve analysis were deteriorated less in the high-methylprednisolone group.

CONCLUSION

Our study suggests that a neutrophil-endothelium interaction via the Mac-1/ICAM-1 pathway is involved in the activation and recruitment of neutrophils in ventilator-induced lung injury. Activation and recruitment of neutrophils were lessened by pretreatment with methylprednisolone, which might have contributed to the improvement of lung dysfunction after mechanical ventilation.

gsk disruption leads to guanosine accumulation in Escherichia coli

We tried some improvement of inosine production using an inosine-producing mutant of Escherichia coli which is deficient in purF (phosphoribosylpyrophosphate (PRPP) amidotransferase gene), purA (succinyl-adenosine 5'-monophosphate (AMP) synthetase gene), deoD (purine nucleoside phosphorylase gene), purR (purine repressor gene) and add (adenosine deaminase gene), and harboring the desensitized PRPP amidotransferase gene as a plasmid. The guaB (inosine 5'-monophosphate (IMP) dehydrogenase gene) disruption brought about a slightly positive effect on the inosine productivity. Alternatively, the gsk (guanosine-inosine kinase gene) disruption caused a considerable amount of guanosine accumulation together with a slight increase in the inosine productivity. The further addition of guaC (guanosine 5'-monophosphate (GMP) reductase gene) disruption did not lead to an increased guanosine accumulation, but brought about the decrease of inosine accumulation.

Investigation of various genotype characteristics for inosine accumulation in Escherichia coli W3110

For the derivation of an inosine-overproducing strain from the wild type microorganism, it is known that the addition of an adenine requirement, removal of purine nucleoside hydrolyzing activity, removal of the feedback inhibition, and repression of key enzymes in the purine nucleotides biosynthetic pathway are essential. Thus, the disruption of purA (adenine requirement), deoD (removal of purine nucleosides phosphorylase activity), purR (derepression of the regulation of purine nucleotides biosynthetic pathway), and the insensitivity of the feedback inhibition of phosphoribosylpyrophosphate (PRPP) amidotransferase by adenosine 5'-monophosphate (AMP) and guanosine 5'-monophosphate (GMP) were done in the Escherichia coli strain W3110, and then the inosine productivity was estimated. In the case of using a plasmid harboring the PRPP amidotransferase gene (purF) that encoded a desensitized PRPP amidotransferase, purF disrupted mutants were used as the host strains. It was found that the innovation of the four genotypes brought about a small amount of inosine accumulation. Furthermore, an adenine auxotrophic mutant of E. coli showed inappropriate adenine use because its growth could not respond efficiently to the concentration of adenine added. As the presence of adenosine deaminase is well known in E. coli and it is thought to be involved in adenine use, a mutant disrupted adenosine deaminase gene (add) was constructed and tested. The mutant, which is deficient in purF, purA, deoD, purR, and add genes, and harboring the desensitized purF as a plasmid, accumulated about 1 g of inosine per liter. Although we investigated the effects of purR disruption and purF gene improvement, unexpectedly an increase in the inosine productivity could not be found with this mutant.

Locking in alternate conformations of the integrin alphaLbeta2 I domain with disulfide bonds reveals functional relationships among integrin domains

We used integrin alphaLbeta2 heterodimers containing I domains locked open (active) or closed (inactive) with disulfide bonds to investigate regulatory interactions among domains in integrins. mAbs to the alphaL I domain and beta2 I-like domain inhibit adhesion of wild-type alphaLbeta2 to intercellular adhesion molecule-1. However, with alphaLbeta2 containing a locked open I domain, mAbs to the I domain were subdivided into subsets (i) that did not inhibit, and thus appear to inhibit by favoring the closed conformation, and (ii) that did inhibit, and thus appear to bind to the ligand binding site. Furthermore, alphaLbeta2 containing a locked open I domain was completely resistant to inhibition by mAbs to the beta2 I-like domain, but became fully susceptible to inhibition after disulfide reduction with DTT. This finding suggests that the I-like domain indirectly contributes to ligand binding by regulating opening of the I domain in wild-type alphaLbeta2. Conversely, locking the I domain closed partially restrained conformational change of the I-like domain by Mn(2+), as measured with mAb m24, which we map here to the beta2 I-like domain. By contrast, locking the I domain closed or open did not affect constitutive or Mn(2+)-induced exposure of the KIM127 epitope in the beta2 stalk region. Furthermore, locked open I domains, in alphaLbeta2 complexes or expressed in isolation on the cell surface, bound to intercellular adhesion molecule-1 equivalently in Mg(2+) and Mn(2+). These results suggest that Mn(2+) activates alphaLbeta2 by binding to a site other than the I domain, most likely the I-like domain of beta2.

An isolated, surface-expressed I domain of the integrin alphaLbeta2 is sufficient for strong adhesive function when locked in the open conformation with a disulfide bond

We introduced disulfide bonds to lock the integrin alphaLbeta2 I domain in predicted open, ligand binding or closed, nonbinding conformations. Transfectants expressing alphaLbeta2 heterodimers containing locked-open but not locked-closed or wild-type I domains constitutively adhered to intercellular adhesion molecule-1 (ICAM-1) substrates. Locking the I domain closed abolished constitutive and activatable adhesion. The isolated locked-open I domain bound as well as the activated alphaLbeta2 heterodimer, and binding was abolished by reduction of the disulfide. Lovastatin, which binds under the conformationally mobile C-terminal alpha-helix of the I domain, inhibited binding to ICAM-1 by alphaLbeta2 with wild-type, but not locked-open I domains. These data establish the importance of conformational change in the alphaL I domain for adhesive function and show that this domain is sufficient for full adhesive activity.

Ventilator-induced lung injury is associated with neutrophil infiltration, macrophage activation, and TGF-beta 1 mRNA upregulation in rat lungs

Activated neutrophils contribute to the development of ventilator-induced lung injury (VILI) caused by high-pressure mechanical ventilation. However, exact cellular and molecular mechanisms have not been conclusively studied. Our investigation aimed to examine expression of adhesion molecules by both neutrophils and macrophages in lung lavage fluids of rats with VILI. Further, involvement of proinflammatory (tumor necrosis factor-alpha) and profibrogenetic (transforming growth factor-beta 1) mediators was analyzed at mRNA level in lung tissue. Wistar rats were ventilated by high pressure (45 cm H(2)O of peak inspiratory pressure, n = 23) or low pressure (7 cm H(2)O, n = 13) with 0 positive end-expiratory pressure. After 40 min of comparative ventilation, lung lavage was performed in 20 rats from the experimental group and 10 from the control for immunofluorescence analysis with anti-Mac-1 and anti-ICAM-1 monoclonal antibodies. The lung tissues from remaining rats were subjected to pathological and reverse transcription-polymerase chain reaction examinations. Although there was no significant change of PaO(2) in the low-pressure group, PaO(2) was decreased in the high-pressure group. The high-pressure group also had greater neutrophil infiltration into alveolar spaces, upregulation of CD54 and CD11b on alveolar macrophages, and more transforming growth factor-beta 1 mRNA in lung tissues. Tumor necrosis factor-alpha was not involved in the pathogenesis of the severe VILI observed. Histologic findings also demonstrated more infiltrating neutrophils, destructive change of the alveolar wall, and deposition of matrix in the high-pressure group. These results suggest that a series of proinflammatory reactions and profibrogenetic process may be involved in the course of VILI.

Effects of box weight, vertical location and symmetry on lifting capacities and ratings on category scale in Japanese female workers

The aim was to clarify the effects of box weight, vertical location and symmetry on the lifting capacities and subjective burden in Japanese female workers with manual material handling tasks. Sixteen healthy females were tested. They performed 12 different lifting tasks (three heights * two weights * two symmetries). It is difficult for Japanese women to exert dynamic force in lifting a 15-kg weight from the elbow to the shoulder level. A remarkable increase was observed in heart rate and category scale with ratio properties (CR-10) on large muscle group in lifting a 15-kg weight as compared with lifting a 10-kg one. Judging from calculation of the Recommended Weight Limit using the application manual by the National Institute for Occupational Safe and Health, it was also suggested that lifting the 15-kg weight from the elbow to the shoulder level was difficult for female workers. Not only peak force, but also the average upward acceleration and peak velocity were lower in asymmetric liftings than those in symmetric liftings. CR-10 for the left back and right thigh were also higher in 90 degrees right lateral plane lifting than in the mid-sagittal plane. Thus, asymmetric lifting was supposed to impose higher stress on the back contralaterally and thigh ipsilaterally to the location of the weight.

Phosphorylation of guanosine using guanosine-inosine kinase from Exiguobacterium acetylicum coupled with ATP regeneration

Guanosine 5'-monophosphate (5'-GMP) and inosine 5'-monophosphate (5'-IMP) are widely used as flavor enhancers. Recently, a novel process for 5'-IMP production by phosphorylation of inosine using guanosine-inosine kinase coupled with ATP regeneration was reported. In this study, we demonstrated the practical possibility of producing 5'-GMP by phosphorylation of guanosine using a guanosine-inosine kinase from Exiguobacterium acetylicum coupled with ATP regeneration.

Computational design of an integrin I domain stabilized in the open high affinity conformation

We have taken a computational approach to design mutations that stabilize a large protein domain of approximately 200 residues in two alternative conformations. Mutations in the hydrophobic core of the alphaMbeta2 integrin I domain were designed to stabilize the crystallographically defined open or closed conformers. When expressed on the cell surface as part of the intact heterodimeric receptor, binding of the designed open and closed I domains to the ligand iC3b, a form of the complement component C3, was either increased or decreased, respectively, compared to wild type. Moreover, when expressed in isolation from other integrin domains using an artificial transmembrane domain, designed open I domains were active in ligand binding, whereas designed closed and wild type I domains were inactive. Comparison to a human expert designed open mutant showed that the computationally designed mutants are far more active. Thus, computational design can be used to stabilize a molecule in a desired conformation, and conformational change in the I domain is physiologically relevant to regulation of ligand binding.

Does blood type B protect against haemolytic uraemic syndrome? An analysis of the 1996 Sakai outbreak of Escherichia coli O157:H7 (VTEC O157) infection. The Osaka HUS Critical Care Study Group

OBJECTIVES

Expression of the P1 blood type antigen is suggested to have a protective effect against post-enteropathic haemolytic uraemic syndrome (HUS). The B blood type may also protect against HUS, since terminal trisaccharide sequences similar to those of the B blood type determinants are reported to have an affinity to Vero cytotoxin that is 23% as strong as that of the P1 determinants. Thus, we studied whether ABO blood types were related to the occurrence or severity of HUS.

METHODS

We obtained clinical and laboratory data of 49 HUS patients treated in 14 critical care facilities during the 1996 Escherichia coli O157:H7 outbreak in Sakai, Japan. We retrospectively studied whether ABO blood types were related to the occurrence or severity of HUS.

RESULTS

The numbers of patients with blood types A, B, O or AB were 29, 8, 12, and 0, respectively. For each blood type, the number of patients with severe renal complications was 16, 6, 9, and 0, respectively. The distribution of blood types among the HUS patients deviated from a population-based distribution of blood types (P<0.05, Chi-squared test); i.e., the frequency of the A blood phenotype was significantly higher among our HUS patients. However, there was no significant difference in the frequency of patients with the A antigen (A and AB blood groups) among our HUS patients, whereas the frequency of B antigen expression was significantly lower (P<0.05, Chi-squared test). The risk of severe renal complications did not appear to be related to ABO blood types.

CONCLUSIONS

Our data suggest that expression of the B antigen has a protective effect against the onset of HUS, but that it does not affect the severity of the disease.

End-product regulation and kinetic mechanism of guanosine-inosine kinase from Escherichia coli

Escherichia coli guanosine-inosine kinase was overproduced, purified, and characterized. The native and subunit molecular weights were 85,000 and 45,000, respectively, indicating that the enzyme was a dimer. A pI of 6.0 was obtained by isoelectric focusing. In addition to ATP, it was found that deoxyadenosine 5'-triphosphate, UTP, and CTP could serve as phosphate donors. The phosphate acceptors were guanosine, inosine, deoxyguanosine and xanthosine, but not adenosine, cytidine, uridine, or deoxythymidine. Maximum activity was attained at an ATP/Mg2+ concentration ratio of 0.5. In the presence of pyrimidine nucleotides, enzyme activity was slightly increased, while it was markedly inhibited by GDP and GTP. Initial velocity and product inhibition studies support an ordered Bi Bi mechanism in which guanosine was the first substrate to bind and GMP was the last product to be released. Guanosine kinase may be a regulatory enzyme that has a role in modulating nucleotide levels.

Development of an improved assay for purine nucleoside kinase activity in cell extracts and detection of inosine kinase activity in Brevibacterium acetylicum ATCC 953, related species, and Corynebacterium flaccumfaciens ATCC 6887

An improved assay was developed to detect direct purine nucleoside phosphorylating activity in cell-free extracts. Direct inosine phosphorylating activity was detected in 2 of 70 species tested. Both activities, which depended on magnesium ion and ATP, phosphorylated a hydroxyl group at the 5' position of inosine. The new assay was shown to be useful for screening of direct purine nucleoside phosphorylating activity and have the potential to detect inosine kinase in the presence of a background of nucleoside phosphorylase and purine phosphoribosyltransferase activities. Previously, the latter two activities made it difficult to correctly detect direct phosphorylation of inosine by inosine kinase.

Associations of self estimated workloads with musculoskeletal symptoms among hospital nurses

OBJECTIVES

To investigate the prevalence of neck, shoulder, and arm pain (NSAP) as well as low back pain (LBP) among hospital nurses, and to examine the association of work tasks and self estimated risk factors with NSAP and LBP.

METHODS

A cross sectional study was carried out in a national university hospital in Japan. Full time registered nurses in the wards (n = 314) were selected for analysis. The questionnaire was composed of items on demographic conditions, severity of workloads in actual tasks, self estimated risk factors for fatigue, and musculoskeletal pain in the previous month. Rate ratios (RRs) and 95% confidence intervals (95% CIs) were calculated by the Cox's proportional hazards model to study the association of pain with variables related to work and demographic conditions.

RESULTS

The prevalences of low back, shoulder, neck, and arm pain in the previous month were 54.7%, 42.8%, 31.3%, and 18.6%, respectively. The prevalence of musculoskeletal symptoms among hospital nurses was higher than in previous studies. In the Cox's models for LBP and NSAP, there were no significant associations between musculoskeletal pain and the items related to work and demographic conditions. The RRs for LBP tended to be relatively higher for "accepting emergency patients" and some actual tasks. Some items of self estimated risk factors for fatigue tended to have relatively higher RRs for LBP and NSAP.

CONCLUSIONS

It was suggested that musculoskeletal pain among hospital nurses may have associations with some actual tasks and items related to work postures, work control, and work organisation. Further studies, however, are necessary, as clear evidence of this potential association was not shown in the study.

Resolution of racemic carboxylic acids via the lipase-catalyzed irreversible transesterification of vinyl esters

The lipase-catalyzed irreversible transesterification procedure using vinyl esters was applied to the resolution of racemic 2-phenoxypropanoic acids. Aspergillus niger lipase showed high enantioselectivities and reasonable reaction rates. The enantioselectivity was found to be affected profoundly by several variables, e.g., the alcohol as nucleophile, the organic solvent used, and the reaction temperature. A gram-scale resolution of (RS)-2-phenoxypropanoic acid was achieved after optimization of the reaction conditions. Then this irreversible transesterification procedure was applied to the resolution of some related 2-substituted carboxylic acids. Thus, racemic 2-methoxy-2-phenylacetic acid was resolved via the A. niger lipase-catalyzed transesterification of the corresponding vinyl ester. 2-Phenylpropanoic acid and 2-phenylbutanoic acid were resolved using Pseudomonas sp. lipase. A gram-scale resolution of 2-phenylbutanoic acid was achieved by this procedure coupled with the porcine liver esterase-catalyzed hydrolysis of the resulting methyl ester.

Effect of saliva on the growth of Helicobacter pylori

The effect of saliva mixed in culture media from young healthy volunteers on the growth of Helicobacter pylori (H. pylori) was investigated. Saliva was centrifuged at 15,000 rpm for 10 min and the supernatant was mixed with the reference strain of standard H. pylori which was suspended in sterilized physiological saline. The mixture was inoculated onto agar plate and incubated for 3 days. The numbers of colonies were counted. Saliva from a young male volunteer stimulated the growth of H. pylori significantly compared with the control. This result indicates that there may be such individuals who have saliva increasing the growth of H. pylori. But this is the preliminary report and more studies are needed to know what factors in saliva may affect the growth of H. pylori.

Lymphocyte activation is attenuated by stellate ganglion block

BACKGROUND AND OBJECTIVES

Clinical evidence suggests that stellate ganglion block (SGB) might modulate the immune system. Little is known, however, about the immunologic effects of SGB. We examined how SGB affected immune functions by analyzing the activation response of lymphocytes during SGB.

METHODS

Twenty-four volunteers were randomly subdivided into three groups. The SGB group (SGB; n = 9) received 6 mL 1% lidocaine at the sixth cervical vertebra (C6) transverse process and showed Horner's sign and elevation of ipsilateral facial and upper limb temperature. The lidocaine group (n = 7) had 6 mL 1% lidocaine injected into subcutaneous tissue at the neck and showed no remarkable clinical effects. The saline group (placebo; n = 8) received 6 mL saline solution injected at approximately the C6 transverse process and showed no remarkable clinical effects. Peripheral blood samples were drawn before and 30 minutes after drug administration. Samples were incubated for 4 hours under the stimulation of mitogen. Using flow cytometry, we measured the de novo expression of CD69, which is one of the initial markers of lymphocyte activation and which reflects the cell activation process. The changes in pre- and post-values were calculated and compared among the three groups.

RESULTS

In only the SGB group, the helper T-cell activation was significantly reduced, and the cytotoxic T-cell activation also tended to decrease after SGB.

CONCLUSIONS

SGB may depress immune system activity for a short time, as reflected in the T-cell activation response.

The influence of surgical stress on T cells: enhancement of early phase lymphocyte activation

For the control of postoperative infection, it may be important to understand the possible influences of surgical stress on the host immune system. To this end, we examined how the early phase of lymphocyte activation was affected in patients after major surgery (eight patients with esophageal carcinoma and six undergoing cardiac surgery) using a flow cytometric assay based on expression of the early activation antigen, CD69. Freshly isolated T cell in preoperative and postoperative samples did not express CD69. When peripheral blood mononuclear cells were stimulated in vitro, the expression of CD69 was greatly enhanced in both CD4 and CD8 T cells, compared with the preoperative samples. The proportion of de novo CD69-expressing cells in the CD4 subset was approximately 3 times (Postoperative Day 1) and 4 times (Postoperative Days 2, 3, 5, and 7) greater than those preoperatively, whereas the proportion of de novo CD69-expressing cells in the CD8 subset was approximately 1.5 times (Postoperative Days 2 and 5) and 2 times (Postoperative Day 3) greater than those preoperatively. The proportion of CD69+ cells was significantly greater in the CD4+ subset than in the CD8+ subset during the postoperative period.

IMPLICATIONS

Our results show that major surgical stress enhances the early phase of lymphocyte activation. The augmentation of activation was greater in CD4 (helper) T cells than in CD8 (cytotoxic) T cells.

Molecular characterization of guanosine kinase gene from a facultative alkalophile, Exiguobacterium aurantiacum ATCC 35652

Guanosine kinase activity was identified in an alkalophile, Exiguobacterium aurantiacum ATCC 35652, and the gsk gene encoding it was isolated as a homologous fragment of the Brevibacterium acetylicum gsk. The cloned chromosomal fragment contained an open reading frame which encodes a polypeptide of 308 amino acids with a molecular mass of 33349 Da. The Ex. aurantiacum Gsk shows strong sequence similarity to B. acetylicum Gsk, but possesses five additional amino acids at the C-terminus. An Mr 39200 protein synthesized in Escherichia coli harboring plasmids carrying Ex. aurantiacum gsk was purified and characterized. A 0.9 kb transcript revealed by Northern blot analysis and the presence of a factor-independent terminator structure suggest that Ex. aurantiacum gsk is monocistronic, although B. acetylicum gsk has been shown to be bicistronic. The striking alterations in the 3'-untranslated region resulted in a different gene organization.

Orally administered cholera toxin prevents murine intestinal T cells from staphylococcal enterotoxin B-induced anergy

BACKGROUND & AIMS

Cholera toxin (CT) has been shown to be a strong mucosal adjuvant for the induction of antigen-specific secretory immunoglobulin A (IgA). The mechanism of adjuvant activity of CT is still unknown. The aim of this study was to examine the immunomodulatory function of CT on mucosal T cells using staphylococcal enterotoxin B (SEB) as coadministered oral antigen, because SEB has been shown to directly regulate alpha beta T-cell responses.

METHODS

C3H/HeN mice were orally or systemically immunized with SEB and/or CT. The levels of SEB-specific antibodies and frequencies of CD4(+)Vbeta8(+) T cells were analyzed. SEB-specific T-cell proliferation and cytokine production were also determined.

RESULTS

Neither SEB-specific IgA nor IgG antibodies were induced in feces when SEB was administered alone. This was a result of the clonal deletion and partial unresponsiveness of CD4(+)Vbeta8(+)T cells in Peyer's patches. On the other hand, SEB-specific antibodies were induced by oral immunization with SEB and CT. Although some degree of clonal deletion was induced by oral immunization with SEB and CT, coadministered CT prevented the induction of anergy for CD4(+)Vbeta8(+) T cells in Peyer's patches.

CONCLUSIONS

CT is a powerful immunomodulatory molecule that prevents mucosal T cells from SEB-induced anergy.

Circadian secretion patterns of melatonin after major surgery

Biorhythms, such as regular variation in core body temperature and the pattern of the secretion of melatonin, are thought to be mediated by the same biological clock. Core body temperature is affected by the inflammatory response to major surgery. Apart from the well-known inhibitory effect of bright light on its secretion, melatonin is an exceedingly good marker of one of the central generating systems of circadian rhythms. We sequentially measured the plasma melatonin concentration pattern in patients who had undergone esophagectomy with thoracotomy to elucidate the circadian rhythm after major surgery. From seven patients who had received esophagectomy with thoracotomy for esophageal cancer, plasma concentrations of melatonin were measured using an RIA method. Blood samples were collected via each patient's arterial line at 00.00, 02.00, 04.00, 06.00, 08.00, 12.00, 16.00, 20.00, and 24.00 hr on the first postoperative day for six of the patients, and, for one patient, every 2 hr until the third postoperative day and every 4 hr thereafter until the sixth postoperative day. Four patients out of seven had melatonin concentrations of over 30 pg/ml (mean 34 pg/ml) at 24.00 hr on the first postoperative day. Five patients showed circadian secretion patterns of melatonin during the first postoperative day. One patient whose melatonin concentrations were measured consecutively for 6 days showed a regular circadian secretion pattern through the 6 days of the study. Even the stress caused by extremely invasive surgery did not significantly disturb the melatonin secretion pattern.

Test-retest reliability of isometric and isoinertial testing in symmetric and asymmetric lifting

The aim of this study was to evaluate test-retest reliability of a dynamometer in measuring lifting strength or force parameters under several combinations of ergonomic factors. Thirteen healthy participants were tested on peak force (PF), related variables and isometric strength (IS) twice, at intervals of 3 months. Correlation coefficients for all parameters in the sagittal plane were 0.60-0.85. Coefficients of variations (CVs) of methodology error for PF in the sagittal plane were 6.2-6.9%. Correlation coefficients and CVs for IS at 90 degrees to the lateral plane were 0.51-0.54 and 16.6-17.9%, respectively. In paired t-tests of the parameters under all conditions, there was a significant difference between test and retest. In the test and retest, ratings of perceived exertions for the low back and the right arm in isometric lifting were significantly higher than those in dynamic lifting. It was concluded that the test-retest reliability of dynamic forces in the dynamometer was high. The peak force in the sagittal plane was considered reliable. In isometric lifting, isometric strength in the sagittal plane seemed reliable, while that at right angles to the lateral plane was considered to be less reliable.

Up-regulation of Fas ligand (FasL) mRNA expression in peripheral blood mononuclear cells (PBMC) after major surgery

FasL, which is expressed mainly on activated lymphocytes, can induce apoptosis (programmed cell death) of cells which express Fas. Fas/FasL interaction is primarily beneficial in maintaining immunological and physiological homeostasis by eliminating unnecessary cells. Dysregulation of the interaction, however, leads to tissue damage. We investigated how Fas/FasL levels changed after major surgery. The major aim of this study was to elucidate the involvement of the Fas/FasL system in postoperative inflammation. The investigation involved 10 patients admitted to the intensive care unit after surgery. Although the percentage of Fas+ cells and the amount of Fas expression tended to increase, there was no significant difference between pre- and post-operative samples. In contrast, the levels of FasL mRNA were dramatically up-regulated after operation. Post-operative C-reactive protein (CRP) levels increased and correlated well with FasL levels (r=0.91, P<0.01). Lymphocyte counts decreased after operation and were inversely proportional to FasL levels (r=0.58, P < 0.05). These results suggest that the enhanced FasL expression is likely to be related to systemic inflammatory responses induced during the perioperative period. FasL up-regulation may be involved in the aggravation of tissue damage, including lymphocytopenia, in the early post-operative period.

Epicondylitis among cooks in nursery schools

OBJECTIVES

To investigate the prevalence and risk factors of epicondylitis among cooks in nursery schools in a cross sectional study because they are suspected to have strenuous workloads on the hands and arms.

METHODS

Prevalence of epicondylitis among 209 nursery school cooks and 366 control workers aged 40-59 were studied. Both groups consisted of women workers chosen from 1299 subjects who agreed to participate from 1329 social welfare employees in a city. All workers were interviewed with a questionnaire and had a clinical examination of the tenderness to palpation of epicondyles and epicondylar pain provoked by resisted extension and flexion of the wrist.

RESULTS

Nursery school cooks had a significantly higher prevalence of epicondylitis (11.5%) than the controls (2.5%). In a logistic regression model, job title of the cook was also found to have a strong association with epicondylitis (odds ratio (OR) 5.4, 95% confidence interval (95% CI) 2.4 to 11.9) after adjustment for age, body length, and body mass index. Weaker associations were also found between epicondylitis and suspected job stress or workload scores for mechanical workload and psychosocial stressors based on factor analysis.

CONCLUSIONS

This study supported the hypothesis that nursery school cooks had a higher prevalence of epicondylitis than other workers with less strenuous hand and arm tasks. It was suggested that risk factors of epicondylitis would be multifactorial, including mechanical workload and psychosocial factors.

A comparative study of physical work load in Japanese and Swedish nursery school teachers

Comparisons were made of general and local physical work loads between two groups of 58 Japanese and 15 Swedish nursery school teachers. Heart rate, number of steps, rating of perceived exertion (RPE), frequency and time expended with respect to trunk flexion, sitting/kneeling, and lifting/carrying loads of 1 kg or more were monitored during working hours. The average percentage heart rate increase in the maximal heart rate range was lower in the Japanese than in the Swedish teachers. However, all parameters of local physical work load indicating musculoskeletal stress were higher in the Japanese than in the Swedish teachers. The RPE was slightly higher in the Japanese than in the Swedish teachers. These features of general and local work load in the Japanese teachers were typically observed among the teachers in charge of very young children (0-2 years). The Japanese teachers in charge of children aged 3-5 years, on the other hand, had similar levels of both general and local work load as the Swedish teachers in charge of classes comprising children of various ages (1-5 years). The physical work load measured in the present study was not sufficient to explain the difference in the magnitude of musculoskeletal problems for nursery school teachers in the two countries, and other factors should now be examined.

Bacterial invasion induces interleukin-7 receptor expression in colonic epithelial cell line, T84

The intestinal epithelial layer forms the interface between the external and the internal environments of a host. Since the interleukin-7 (IL-7) and IL-7 receptor (IL-7R) signaling pathway has been shown to play an important role in the mucosal immune system, we studied the expression of IL-7R in T84, a colonic epithelial cell line, after cells were infected with several types of enteropathogenic bacteria, including Salmonella typhimurium, enteropathogenic Escherichia coli and enteroinvasive Escherichia coli. Bacterial invasion induced IL-7R expression in T84 assessed by a semi-quantitative reverse transcription-polymerase chain reaction technique and flow cytometry. The inhibition of bacterial invasion by cytochalasin D, a specific inhibitor of actin polymerization, led to a reduction in the expression of IL-7R. These data indicate that bacterial invasion into intestinal epithelial cells is likely to be an essential process in the induction of IL-7R. The communication between the epithelium and mucosal lymphocytes which is mediated via IL-7 and IL-7R may be involved in the modulation of the mucosal inflammation which occurs in bacterial infection.

Molecular cloning and transcriptional analysis of a guanosine kinase gene of Brevibacterium acetylicum ATCC 953

The Brevibacterium acetylicum gsk gene, which encodes guanosine kinase (ATP:guanosine 5'-phosphotransferase), a kinase that is involved in guanosine salvage pathways, has been cloned by using the N-terminal amino acid sequence of the purified protein. The cloned chromosomal fragment containing the gsk gene was sequenced and shown to encode a polypeptide of 303 amino acids with a molecular mass of 32,536 Da, which is in good agreement with the measured molecular weight of the purified enzyme. Recombinant Escherichia coli strains harboring plasmids carrying the B. acetylicum gsk gene overexpressed both guanosine and inosine kinase activities. The primary structure of the gsk gene shows similarity to amino acid sequences of sugar kinases classified in the ribokinase family stronger than to those of the E. coli gsk gene encoding guanosine kinase and other nucleoside kinases. Northern blot analysis and primer extension analysis revealed a 1.4-kb transcript and promoter sequences, like the E. coli sigma70 and B. subtilis sigmaA consensus sequences, respectively. These results, together with the nucleotide sequence of the downstream region of gsk, suggested that the organization of B. acetylicum gsk is bicistronic. The second gene, orf2, shows significant similarity to the mutT mutator genes of several organisms, although its function has not yet been identified. The gsk gene was specifically transcribed in the early exponential growth phase, which seems to correspond to the specific guanosine kinase activity profile and suggests a role in controlling the nucleoside monophosphate level by efficiently recycling guanosine when cells are in the early exponential phase.

Evaluation of the AMPLICOR CMV test for direct detection of cytomegalovirus in plasma specimens

We evaluated the AMPLICOR CMV test (PCR) for the direct detection of cytomegalovirus in plasma. Sixty-eight specimens were involved for the comparison between the AMPLICOR test and the antigenemia assay. The sensitivities, specificities, and positive and negative predictive values were 97.1, 100, 100, and 97.1%, respectively, for the AMPLICOR test and 79.4, 100, 100, and 82.9%, respectively, for the antigenemia assay.

Tension pneumopericardium following tracheoplasty for congenital tracheal stenosis

Tension pneumopericardium is a rare complication of mechanical ventilation following tracheoplasty for congenital tracheal stenosis. This case report describes fatal tension pneumopericardium in a three-month-old male infant some 24 hours following tracheoplasty for this condition. Because of persisting stenosis of the left main bronchus, ventilation pressures of PIP 23 cm H2O and PEEP 5 cm, progressing to PIP 28 cm and PEEP 7 cm were needed to maintain adequate respiratory exchange. Partial relief of the pneumopericardium was achieved by vigorous cardiac massage, but three days later the infant died of massive airway haemorrhage.

Characterization of guanosine kinase from Brevibacterium acetylicum ATCC 953

Guanosine kinase (GKase) activity was identified in a cell-free extract of Brevibacterium acetylicum ATCC 953. We have purified the enzyme 4000-fold from the cell-free extract to apparent homogeneity. Molecular weight of 71,300 and 36,300 determined by gel filtration and sodium dodecyl sulfate gel electrophoresis, respectively, revealed that the enzyme is a dimer molecule. Maximum activity of the GKase was attained when the magnesium/ATP concentration ratio was close to 1. The GKase activity was dependent on the presence of a divalent cation. The Km values for guanosine, inosine, and 2'-deoxyguanosine as phosphate acceptors were determined to be 0.022, 0.87, and 2.83 mM, respectively. In addition to ATP and dATP, GTP and dGTP were shown to be effective phosphate donors for the GKase. The optimal pH seemed to be around pH 8.3, although relatively high activity was observed in the alkaline pH range of 7.5-9.8. The addition of 0.1 mM pyrimidine nucleotides, especially CMP and CTP, activated the GKase activity. On the other hand, the addition of 1 mM AMP, ADP, and GMP inhibited the GKase activity. It is thus likely that the GKase activity might be regulated in vivo by nucleotide concentrations and may control the nucleoside monophosphate level by efficiently recycling guanosine.

Low back pain among cooks in nursery schools

A cross-sectional questionnaire study was conducted on cooks working for nursery schools in N city in order to verify epidemiological evidence of the work-relatedness of low back pain among them. After female workers aged 30 or more were selected from a study base of 2,799 workers in social welfare facilities, low back pain prevalence of cooks (n = 240) was compared with nursery school teachers (n = 955). Age-standardized prevalence ratios (PRs) of low back pain were 1.9 (95% CI: 1.5-2.5) in cooks compared with nursery school teachers. Among cooks, relative risks of low back pain increased with the increase in the number of lunches to be prepared and decreased with the increase in the number of cooks making lunches in a logistic regression model controlling age and body length. Low back pain was also found to be associated with self-estimated job stressors/ work load by logistic regression models. Multifactorial effects from ergonomic and psychosocial factors, and individual factors on the low back were suggested. From the viewpoint of epidemiological criteria for work-relatedness, it was concluded that the work-relatedness of low back pain among cooks in nursery schools was partially supported.

Nitric oxide induces apoptosis in mouse splenic T lymphocytes

The cytotoxic effect of nitric oxide (NO) on mouse T lymphocytes was investigated. Freshly isolated T lymphocytes from mouse spleen were incubated with NOR, a novel NO releasing agent, at different doses. After incubation for 4 h, apoptotic cell death was observed in both NOR-treated T lymphocytes and controls as judged by the appearance of DNA laddering in agarose gel electrophoresis, but a quantitative analysis by flow cytometry indicated that the high level of exogenous NO (500 micrograms ml of NOR) could promote apoptosis in T lymphocytes as compared with controls (30% vs. 8%). After 8 h, NO promoted apoptosis of T lymphocytes in a dose-dependent manner. This study indicated that NO might be one of the factors which regulate this life of T lymphocytes in vivo.

Ketamine inhibits nitric oxide production in mouse-activated macrophage-like cells

We have investigated the effects of ketamine on nitric oxide produced by activated macrophages using a murine macrophage-like cell line, J774. Cells were incubated for 18 h under stimulation with lipopolysaccharide and interferon-gamma or lipoteichoic acid and interferon-gamma, with various concentrations of ketamine (6-600 mumol litre-1). Nitric oxide production was assessed by measuring nitrite, a stable by-product of nitric oxide breakdown, in the medium. Other N-methyl-D-aspartate receptor antagonists, MK-801 (150 mumol litre-1) and dextromethorphan (150 mumol litre-1) were also tested. In addition, we studied the effects of ketamine on production of tumour necrosis factor-alpha by activated macrophages. Ketamine inhibited nitrite production dose-dependently with both lipopolysaccharide- and lipoteichoic acid-activated macrophages by up to approximately 65% at the highest ketamine concentration (600 mumol litre-1). Neither MK-801 nor dextromethorphan had an inhibitory effect. Ketamine also suppressed production of tumour necrosis factor-alpha. The data show that ketamine inhibited nitric oxide production by activated macrophages probably, in part, via inhibition of production of tumour necrosis factor-alpha, an autocrine stimulatory factor for nitric oxide production, but not via the NMDA receptor pathway, which is involved in neuronal nitric oxide production.

Effects of asymmetric dynamic and isometric liftings on strength/force and rating of perceived exertion

A laboratory study was undertaken to determine the postural and physical characteristics and subjective stress during dynamic lifting of a usual load (10 kg) compared with during isometric lifting. The authors also aimed to clarify the effects of asymmetric lifting on these parameters. The subjects were thirteen male college students. They were asked to lift a box weighing 10 kg. They performed sixteen different lifting tasks from the floor to a height of 71 cm, involving a combination of three independent factors: two lifting modes (isometric lifting and dynamic lifting), four lifting angles in relation to the sagittal plane (sagittal plane, right 45 degree, right 90 degree and left 90 degree planes) and two lifting postures (squat and stoop). For each lifting task, strengths or forces and ground reaction forces were measured. At the end of each task, the authors asked the subjects to rate their perceived exertion (RPE) during lifting at ten sites of the body. Angle factor had a significant effect on isometric strengths and dynamic peak forces. Isometric strengths during the maximum 3 s were highest in lifting in the right 45 degree plane, followed by that in the sagittal plane, while those in the right 90 degree and left 90 degree planes were the lowest. However, peak forces in dynamic lifting were the highest in the lifting in the sagittal plane, followed by that in the right 45 degree plane, while those in the right 90 degree and left 90 degree planes were the lowest. Postural factor had a significant effect on height at peak force, which is higher in squat lifting than in stoop lifting. RPEs for the left arm, the backs and the right whole body in isometric lifting were significantly higher than in dynamic lifting of 10 kg. There were remarkably high RPEs for the ipsilateral thigh to the box in right 90 degree and left 90 degree planes during both isometric and dynamic liftings. Locations of the resultant force consisting of three component forces on the force plate were closer to the foot on the same side as the box in asymmetric lifting. Thus, some similarities and differences were found between isometric lifting and dynamic liftings regarding the indexes of strength used in this experiment. The authors consider that the subjects used the foot nearer to the box as a fulcrum during asymmetric lifting. Dynamic measurement using the 10 kg weight is less stressful than the conventional isometric measurement. It was possible to obtain the height data at peak force and time-based changes in the force and the box location during lifting only through dynamic lifting measurement. The results provide new knowledge about the biomechanical features of dynamic lifting tasks.

Detection of the gene for toxic shock syndrome toxin 1 in Staphylococcus aureus by enzyme-labelled oligonucleotide probes

A colony hybridisation method with enzyme-labelled oligonucleotide probes was developed to detect the gene for toxic shock syndrome toxin 1 (tst). For rapid identification, bacterial colonies were transferred from agar plates directly on to nylon membranes. These procedures took only 3 h. Results obtained by this test correlated well with those obtained by the reverse passive latex agglutination test. Thus, this method is convenient and reliable for the detection of tst in staphylococci, which could be useful for both research and clinical purposes. This method demonstrated that tst was more prevalent in methicillin-resistant Staphylococcus aureus (56%) than in methicillin-susceptible S. aureus (4%).

Fucoidin, a potent inhibitor of leukocyte rolling, prevents neutrophil influx into phorbol-ester-induced inflammatory sites in rabbit lungs

The polysaccharide fucoidin, a homopolymer of sulfated L-fucose, is known, by interfering with the function of L-selectin, to inhibit leukocyte rolling, which is an early and essential step in the process of leukocyte extravasation into inflamed sites. We tested the inhibitory effect of fucoidin on neutrophil accumulation in lung inflammation induced by phorbol myristate acetate and peritoneal inflammation induced by thioglycollate in rabbits. Pretreatment (10 mg/kg) followed by continuous administration (10 mg/kg/h) of fucoidin dramatically reduced the number of neutrophils recruited into the lungs (determined by neutrophil counts in bronchoalveolar lavage fluid; 97.7 +/- 0.52% reduction) and peritoneal cavity (determined by neutrophil counts in peritoneal lavage fluid; 98.4 +/- 1.29% reduction). Fucoidin treatment also increased the systemic neutrophil count. These results suggest that the inhibition of leukocyte rolling, which may be a primary function of fucoidin, leads to a reduction of neutrophil accumulation at inflammatory sites, which may be beneficial for attenuating neutrophil-mediated tissue injury.