Acute changes in bladder volume produce minimal cardio-respiratory responses in lightly anesthetised humans

PURPOSE

To examine whether changes in bladder volume elicit reflex cardiovascular and respiratory responses in humans under general anesthesia with sevoflurane and nitrous oxide.

METHODS

Fourteen patients free of autonomic disorders were anesthetized with sevoflurane 0.5% and nitrous oxide 60% in oxygen that were approximately equivalent to 0.9 MAC. Warmed saline (6 ml x kg(-1), 37 degrees C) was instilled into the pre-emptied urinary bladder, and then the bladder was kept distended for five minutes. Following the distension, the instilled saline was drained to the pre-instilled volume of the bladder Arterial blood pressure, respiratory flow, and intra-vesicle pressure were continuously measured, and mean arterial pressure, pulse rate, respiratory rate, tidal volume, and minute ventilation were estimated offline from these signals.

RESULTS

Bladder emptying produced small decreases in mean blood pressure (from 83.4+/-4.3 to 80.0+/-4.4 mm Hg, mean +/- SE, P = 0.017) and pulse rate (from 72.2+/-2.9 to 69.4+/-2.7 bpm, mean +/- SEM, P = 0.004). Only minimal respiratory reflexes were invoked by the bladder volume changes.

CONCLUSION

In lightly anesthetized humans, the acute changes in bladder volume produce only mild cardiovascular and respiratory responses.

Crystal structure of the holliday junction DNA in complex with a single RuvA tetramer

In the major pathway of homologous DNA recombination in prokaryotic cells, the Holliday junction intermediate is processed through its association with RuvA, RuvB, and RuvC proteins. Specific binding of the RuvA tetramer to the Holliday junction is required for the RuvB motor protein to be loaded onto the junction DNA, and the RuvAB complex drives the ATP-dependent branch migration. We solved the crystal structure of the Holliday junction bound to a single Escherichia coli RuvA tetramer at 3.1-A resolution. In this complex, one side of DNA is accessible for cleavage by RuvC resolvase at the junction center. The refined junction DNA structure revealed an open concave architecture with a four-fold symmetry. Each arm, with B-form DNA, in the Holliday junction is predominantly recognized in the minor groove through hydrogen bonds with two repeated helix-hairpin-helix motifs of each RuvA subunit. The local conformation near the crossover point, where two base pairs are disrupted, suggests a possible scheme for successive base pair rearrangements, which may account for smooth Holliday junction movement without segmental unwinding.

Effect of P(2)' site tryptophan and P(20)' site deletion of Momordica charantia trypsin inhibitor II on inhibition of proteinases

Momordica charantia trypsin inhibitor II (MCTI-II) inhibits the amidolytic activity of factor Xa with a K(i) value 10-100-fold smaller than those of other squash family inhibitors. It also inhibits factor X activation mediated by factor VIIa-tissue factor complex or factor IXa. Comparison of other squash family inhibitors reveal Trp at position 7 (P(2)') and a deletion at position 25 (P(20)') are characteristics of MCTI-II. In order to elucidate the effect of these positions on the inhibitory activity, we chemically synthesized three inhibitors: S-MCTI-II whose amino acid sequence is identical to natural MCTI-II, S-MCTI-II(7L) whose P(2)'(Trp) is substituted with Leu, and S-MCTI-II(25N) whose P(20)'(deletion) is filled with Asn. The dissociation constants of the complexes of human factor Xa with S-MCTI-II, S-MCTI-II(7L), and S-MCTI-II(25N) were 1.3x10(-6) M, 2.8x10(-5) M, and 7.3x10(-6) M, respectively. They inhibited factor X activation mediated by factor VIIa with the same degree. As in the case of natural MCTI-II, S-MCTI-II suppressed factor X activation mediated by factor IXa, while S-MCTI-II(7L) and S-MCTI-II(25N) did not. Both the Trp at the P(2)' position and deletion at the P(20)' position are thus likely required for the inhibition of factor Xa, trypsin, and factor IXa, while these two positions do not affect factor X activation initiated by the factor VIIa-tissue factor complex.

Mechanism of product chain length determination for heptaprenyl diphosphate synthase from Bacillus stearothermophilus

A member of the medium-chain prenyl diphosphate synthases, Bacillus stearothermophilus heptaprenyl diphosphate synthase, catalyzes the consecutive condensation of isopentenyl diphosphate with allylic diphosphate to produce (all-E)-C35 prenyl diphosphate as the ultimate product. We previously showed that the product specificity of short-chain prenyl diphosphate synthases is regulated by the structure around the first aspartate-rich motif (FARM). The FARM is also conserved in a subunit of heptaprenyl diphosphate synthase, component II', which suggests that the structure around the FARM of component II' regulates the elongation. To determine whether component II' regulates the product chain length by a mode similar to that of the short-chain prenyl diphosphate synthases, we replaced a bulky amino acid at the eighth position before the FARM of component II', isoleucine 76, by glycine and analyzed the product specificity. The mutated enzyme, I76G, can catalyze condensations of isopentenyl diphosphate beyond the native chain length of C35. Moreover, two mutated enzymes of A79Y and S80F, which have a single replacement to the aromatic residue at the fourth or the fifth position before the FARM, mainly yielded a C20 product. These results strongly suggest that a common mechanism controls the product chain length of both short-chain and medium-chain prenyl diphosphate synthases and that, in wild-type heptaprenyl diphosphate synthase, the prenyl chain can grow on the surface of the small residues at positions 79 and 80, and the elongation is precisely blocked at the length of C35 by isoleucine 76.

Adrenomedullin gene transcription is decreased in peripheral blood mononuclear cells of patients with IgA nephropathy

We measured mRNA levels of adrenomedullin (AM), C-type natriuretic peptide (CNP), vascular endothelial growth factor (VEGF), interleukin 1beta (IL-1beta) and interleukin 6 (IL-6) in peripheral blood mononuclear cells (PBMC) of patients with IgA nephropathy. To evaluate these mRNA levels, we employed a real-time quantitative PCR method which was performed using a hybridization probe labeled with two fluorescence dyes. This strategy was found to afford the standard curves with a high correlation, suggesting that this method is useful for evaluations of mRNA levels. By this method, levels of AM, CNP, VEGF, IL-1beta and IL-6 mRNA in PBMC of 49 IgA nephropathy patients and 35 healthy volunteers were evaluated. Among the mRNAs examined, AM mRNA levels were significantly lower in severe-grade than in mild-grade IgA nephropathy patients. Furthermore, AM mRNA levels correlated with CNP mRNA levels in PBMC of patients with IgA nephropathy, and each peptide generated from these mRNAs has antiproliferative effects on mesangial cells. These data indicate that gene expression of AM in PBMC is regulated according to the pathophysiological states of IgA nephropathy and that decreased AM production may contribute to the progression of IgA nephropathy.

Patient access to medical records: problems and strategies for inpatient charts

Fasing the impending introduction of patient access to medical charts, we have attempted to include a more substantial description of medical activity in specific areas. Using the guidelines published jointly by the Ministry of Health and Welfare and the Tokyo Metropolitan Office in October 1998, the staff of the medical records division examined and evaluated the layout and description of items on individual hospital charts, with excellent results. To encourage the continued improvement of medical chart recording in the future, incentives should be implemented to avoid insufficient descriptions, encourage regular chart inspections, and promote education regarding the need for a systematic approach to charts and chart recording.

In vitro activity of DU-6681a, an active form of the new oral carbapenem compound DZ-2640, in comparison with that of R-95867, faropenem and oral cephalosporins

We compared the in vitro antibacterial activity of DU-6681a against Gram-positive and Gram-negative bacteria with that of R-95867, faropenem and oral cephalosporins such as cefcapene, cefotiam and cefpodoxime. DU-6681a is an active form of the new oral carbapenem compound DZ-2640, which is an ester-type prodrug, and R-95867 is an active form of the oral carbapenem CS-834. Against most Gram-positive bacteria, DU-6681a was as active as or two- to 16-fold more potent than R-95867 and faropenem in terms of MIC(90), and comparable to or two- to 64-fold more effective than the cephalosporins. Against most Gram-negative bacteria, the activity of DU-6681a was the same as or two- to 16-fold more potent than that of R-95867, and comparable to or two- to 2048-fold higher than that of faropenem and the cephalosporins.

Usefulness of continuous oxygen insufflation into trachea for management of upper airway obstruction during anesthesia

BACKGROUND

Severe complications associated with upper airway obstruction often occur during the perioperative period. Development of a simple and reliable technique for reversing the impaired airway patency may improve airway management. The purpose of the current study is to evaluate the usefulness of transtracheal oxygen insufflation (TTI) for management of upper airway obstruction during anesthesia and to explore the mechanisms of TTI in detail.

METHODS

During propofol anesthesia in eight spontaneously breathing patients, the upper airway cross-sectional area and pressure-flow measurements during neck flexion with TTI were compared with those during triple airway maneuvers (TAM) without TTI. Blood gas analyses assessed efficacy of CO2 elimination during TTI in an additional nine patients.

RESULTS

TTI achieved adequate PaCO2 and PaO2 levels equivalent to those during TAM. In addition to a significantly smaller cross-sectional area during TTI, the location and slope of the pressure-flow relation during TTI completely differed from those during TAM, indicating that upper airway resistance was much higher during TTI. Notably, minute ventilation during TTI was significantly smaller than that during TAM, suggesting reduced dead space or other mechanisms for CO2 elimination.

CONCLUSIONS

TTI is capable of maintaining adequate blood gases through mechanisms different from those of conventional airway support in anesthetized subjects with upper airway obstruction.

Inhaled furosemide greatly alleviates the sensation of experimentally induced dyspnea

Furosemide is known to influence the activity of vagally mediated mechanoreceptors in the airways. Because vagal afferent fibers may play an important role in modulation of the sensation of dyspnea, it is possible that inhaled furosemide may modify the sensation of dyspnea. In a double-blind, randomized, crossover study, we compared the effect of inhaled furosemide on dyspneic sensation with that of placebo. Severe dyspneic sensation was induced in 12 healthy subjects in two ways: (1) breathholding and (2) loaded breathing with a combination of inspiratory resistive load (240 cm H(2)O/L/s) and hypercapnia induced by extra mechanical dead space (0.26 L). Subjects were asked to rate their sensation of respiratory discomfort using a visual analogue scale (dyspneic VAS). Breathholding times and changes in dyspneic VAS score during a 5-min period of loaded breathing were measured after inhalation of placebo and furosemide (40 mg). Total breathholding time after inhalation of furosemide (median, 93 [interquartile range, 78 to 112]s) was prolonged compared with the total breathholding time after placebo inhalation (67 [47-74]s). We also found that respiratory discomfort during loaded breathing after inhalation of furosemide develops more slowly and is less than that observed after inhalation of placebo. Our findings indicate that inhaled furosemide greatly alleviates the sensation of dyspnea induced experimentally by breathholding and by a combination of resistive loading and hypercapnia.

Modulation of RuvB function by the mobile domain III of the Holliday junction recognition protein RuvA

In prokaryotes, RuvA-RuvB complexes play a crucial role in the migration of the Holliday junction, which is a key intermediate of homologous recombination. RuvA binds to the Holliday junction and enhances the ATPase activity of RuvB required for branch migration. RuvA adopts a unique domain structure, which assembles into a tetrameric molecule. The previous mutational and proteolytic analyses suggested that mutations in a carboxyl-terminal domain (domain III) impair binding of RuvA to RuvB. In order to clarify the functional role of each domain in vitro, we established the recombinant expression systems, which allow us to analyze structural and biochemical properties of each domain separately. A small-angle X-ray scattering solution study, combined with X-ray crystallographic analyses, was applied to the tetrameric full-length RuvA and its tetrameric NH2 region (domains I and II) lacking the domain III. These results demonstrated that domain III can be completely separate from the tetrameric major core of the NH2 region and freely mobile in solution, through a remarkably flexible loop. Biochemical analyses indicated that domain III not only interacts with RuvB, but also modulates its ATPase activity. This modulation may facilitate the dynamic coupling between RuvA and RuvB during branch migration.

Sequence motif-specific assignment of two [2Fe-2S] clusters in rat xanthine oxidoreductase studied by site-directed mutagenesis

The sequence motif-specific assignment of the two distinct [2Fe-2S] clusters in rat xanthine oxidoreductase (XOR) was unequivocally established by site-directed mutagenesis of recombinant enzymes expressed in a baculovirus-insect cell system and electron paramagnetic resonance (EPR) spectroscopy. The conserved cysteine residues, including Cys-115, in the unusual C-terminal -Cys-Xaa(2)-Cys-//-Cys-Xaa(1)-Cys- motif serve as ligands to the Fe/S I center, which is probably located in close proximity to the Mo-pterin center. Other conserved cysteine residues, including Cys-43 and Cys-51, in the N-terminal plant ferredoxin-like motif serve as ligands to the Fe/S II center, which is distantly located from the Mo-pterin center. The present sequence motif-specific assignment of the Fe/S I and II centers is discussed in the light of the structural features of XOR.

Transit of radical scavenging activity of milk products prepared by Maillard reaction and Lactobacillus casei strain Shirota fermentation through the hamster intestine

Oxidative stress in the colon is associated with the incidence of colon cancer. In situ, the suppression of oxidative stress in the colon would be an effective form of prevention of the cancer. In this study we investigated the transit of the radical scavenging activity of milk products through the hamster intestinal tract. Two types of skim milk products were prepared by Maillard reaction and then lactic acid fermentation. Heat treatment enhanced the radical scavenging activity for 2,2-diphenyl-1-picrylhydrazyl radical of skim milk. The activity was further increased by fermentation with Lactobacillus casei strain Shirota. Normal hamsters were fed these milk products for 14 d. For potential radical scavenging activity per unit dry weight of feces and cecal content, the groups ranked in the order of fermented product-fed hamsters > heated product-fed hamsters > control hamsters, reflecting the order of the potential of the corresponding diets. Approximately 12% of the activity of the heated and the fermented product diets passed through the gastrointestinal tract. These results suggest that some of the radical scavenging activity generated by food processing reached the colon in nonabsorbable products.

Dose-dependent effects of mandibular advancement on pharyngeal mechanics and nocturnal oxygenation in patients with sleep-disordered breathing

STUDY OBJECTIVES

To examine dose-dependent effects of mandibular advancement on collapsibility of the passive pharynx and sleep-disordered breathing (SDB).

DESIGN

Prospective, randomized study.

SETTING

University hospital.

PATIENTS

Thirty-seven adult patients with SDB.

INTERVENTIONS

Oral appliances with 2-, 4-, and 6-mm advancement of the mandible.

MEASUREMENTS AND RESULTS

Overnight oximetry was performed with and without oral appliances. Each 2-mm mandibular advancement coincided with approximately 20% improvement in number and severity of nocturnal desaturations. Percentages of patients producing a > 50% improvement rate of the number of desaturations were 25%, 48%, and 65% with use of oral appliances with 2-, 4-, and 6-mm mandibular advancement, respectively. Static pharyngeal mechanics were evaluated in six completely paralyzed patients with SDB under general anesthesia with and without the oral appliances. Advancement of mandibular position was found to produce dose-dependent closing pressure reduction of all pharyngeal segments. Normalization of nocturnal oxygenation was associated with negative closing pressure, especially at the velopharynx.

CONCLUSIONS

We conclude that improvement of both nocturnal oxygenation and pharyngeal collapsibility significantly depends on the mandibular position.

[Changes in the antibacterial activity of chemotherapeutic agents (especially carbapenems) for 10 species of clinical isolates between 1994 and 1996. Surveillance group of the sensitivities of clinical isolates to antibacterial agents]

During October and December of each year of from 1994 to 1996, 3,849 strains of 10 species of bacteria were isolated from clinical materials in 21 institutions nationwide. The minimum inhibitory concentrations (MICs) for these bacteria of four carbapenems (imipenem [IPM], panipenem [PAPM], meropenem [MEPM], and biapenem [BIPM]) and other representative antibacterial agents were measured to investigate annual changes in antibacterial activity. Carbapenems showed potent activity against methicillin-sensitive S. aureus (MSSA), S. pneumoniae, E. faecalis, H. influenzae, E. coli, K. pneumoniae, E. cloacae, S. marcescens, and the B. fragilis group, with the activity being stable. However, these drugs showed weak activity against methicillin-resistant S. aureus (MRSA) and P. aeruginosa. The antibacterial activity (MIC90) against the tested organisms generally remained stable. Particularly, there was annual improvement of the MIC90 values of IPM and BIPM for S. pneumoniae, as well as the values of IPM and PAPM for H. influenzae, and those of IPM, PAPM, and BIPM for S. marcescens. On the other hand, the activity of carbapenems (including IPM) against MRSA was not necessarily strong, but there was annual improvement of MIC90 values.

Pre-and post-operative respiratory assessment of acromegalics with sleep apnea--bedside oximetric study for transsphenoidal approach

PURPOSE

Although routine mechanical nasal packing after transsphenoidal surgery (TS) is thought to increase respiratory disorders during sleep, there has been little in the literature about the pre- and post-operative airway assessment of acromegalics with sleep apnea (SA). We describe 4 acromegalic patients with SA, who underwent transsphenoidal surgery. METHODS AND CASES: The patients were all men, aged from 47 to 59 years. The pre- and post-operative sleep study consisted with a computer calculated oximetry parameter of oxygen desaturation index (ODI), which was defined as the number/hour of oxygen desaturation episodes exceeding 4% from the base line (normal range < 15). The postoperative (postop.) sleep study was carried out from the 1st postop. day to the 8th day, for 1 to 8 days, varying for each patient.

RESULTS

Only the worst postop. result is shown. Patient 1 had 2 operations, 2 years apart. ODI was 39.6 before the 1st operation and 45.9 postop.. In the second operation ODI was 21.8 preoperatively (preop.) and 57.9 postop.. Preop. and postop. ODI was 18.1 and 22.2 in patient 2, 21.6 and 22.5 in patient 3 and 45.5 and 18.9 in patient 4, respectively. ODI of patient 4 was 39.6, 3 weeks later.

CONCLUSION

Our data showed that the postop. oxymetric study commonly showed worse results in acromegalics with nasal packing. The better result of patient 4 was probably due to a postop. sleepless state. REM sleep usually increases in the first several postop. days, when cardiopulmonary complications are more likely to occur. Since acromegalics with severe SA and postop. nasal packing may more readily suffer from cardiopulmonary complications, postoperative meticulous respiratory monitoring and care should be mandatory.

Zinc-finger genes that specifically express in pistil secretory tissues of petunia

Tissue-specific expression patterns of petunia zinc-finger genes, ZPT2-10 and ZPT3-3, were analyzed by using GUS reporter system. The GUS expression directed by ZPT2-10 promoter was specifically found in the stylar transmitting tissue of pistil, and that by ZPT3-3 promoter in stigmatic and stylar transmitting tissues. These tissues play important roles in reproductive process. We discuss possible roles of the zinc-finger proteins in these specialized tissues.

Physiological and pathophysiological implications of upper airway reflexes in humans

The upper airway is a vital part of the respiratory tract. Although the upper airway serves several functions, protection of the airway and preservation of airway patency are the most essential functions subserved by upper airway reflexes. Various types of nerve endings have been identified in and under the epithelium of the upper airway, and afferent nerve endings are the natural starting of all reflex activity. The upper airway reflexes consist of many different types of reflex responses such as sneezing, apnea, swallowing, laryngeal closure, coughing, expiration reflex, and negative pressure reflex. Although the activation of upper airway reflexes does not necessarily occur at one particular site of the respiratory tract, individual reflex response is usually considered to be highly specific for the particular respiratory site which has been affected. The upper airway reflexes are modified by many factors such as sleep, anesthesia, and background chemical ventilatory drive. Both depression and exaggeration of upper airway reflexes cause clinical problems. Depression of upper airway reflexes enhances the chance of pulmonary aspiration and compromises the maintenance of the airway, whereas exaggeration of airway reflexes such as laryngospasm and prolonged paroxysm of cough can be harmful and dangerous. In this review, various aspects of upper airway reflexes are discussed focusing on the functions of upper airway reflexes in humans and some pathophysiological problems related to clinical medicine.

Intersubunit location of the active site of farnesyl diphosphate synthase: reconstruction of active enzymes by hybrid-type heteromeric dimers of site-directed mutants

Farnesyl diphosphate synthase is a homodimer of subunits having typically two aspartate-rich motifs with two sets of substrate binding sites for an allylic diphosphate and isopentenyl diphosphate per molecule of a homodimeric enzyme. To determine whether each subunit contains an independent active site or whether the active sites are created by intersubunit interaction, we constructed several expression plasmids that overproduce hybrid-type heterodimers of Bacillus stearothermophilus FPP synthases constituting different types of mutated monomers, which exhibit little catalytic activity as homodimers, by combining two tandem fps genes for the manipulated monomer subunit with a highly efficient promoter trc within an overexpression pTrc99A plasmid. A heterodimer of a combination of subunits of the wild type and of R98E, a mutant subunit which exhibits little enzymatic activity as a dimer form (R98E)(2), exhibited 78% of the activity of the wild-type homodimer enzyme, (WT)(2). Moreover, when a hybrid-type heterodimeric dimer of FPP synthase mutant subunits (R98E/F220A) was prepared, the FPP synthase activity was 18- and 390-fold of that of each of the almost inactive mutants as a dimeric enzymes, (R98E)(2) and (F220A)(2) [Koyama, T., et al. (1995) Biochem. Biophys. Res. Commun. 212, 681-686], respectively. These results suggest that the subunits of the FPP synthase interact with each other to form a shared active site in the homodimer structure rather than an independent active site in each subunit.

An active-site mutation causes enhanced reactivity and altered regiospecificity of transglucosylation catalyzed by the Bacillus sp. SAM1606 α-glucosidase

Bacillus sp. SAM1606 alpha-glucosidase catalyzes the transglucosylation of sucrose to produce three regioisomers of the glucosylsucroses, with theanderose (6-O(G)-glucosylsucrose) as the most abundant transfer product. To find the active-site amino acid residues which can affect the reactivity and regiospecificity of the glucosyl transfer, 16 mutants with amino acid substitutions near the active site were allowed to react with 1.75 M sucrose at 60 degrees C, pH 6.0, and the course of transglucosylation as well as the product specificity were analyzed. The sites of the amino acid substitutions were selected by comparing the conserved amino acid sequences located near the active site of the SAM1606 enzyme with those of the Bacillus oligo-1,6-glucosidases (O16G), which have very high amino acid sequence similarities near the active site but have a distinct substrate specificity. The results showed that, among the mutated SAM1606 enzymes examined, only the mutants with substitution of Gly273 with Pro showed an altered reactivity and specificity of transglucosylation; these mutants exhibited a significantly enhanced initial velocity of glucosyl transfer, yielding isomelezitose (6-O(F)-glucosylsucrose) instead of theanderose as the major transfer product. These results indicate that the substitution of Gly273 with Pro critically governs the enhanced reactivity and altered specificity of the transglucosylation. The notion that the amino acid residue at this position is the determinant of the glucosyl-transfer specificity was further confirmed by observation that the Bacillus cereus O16G, which has a proline at the corresponding position, produced isomelezitose as the major transfer product during transglucosylation with sucrose.

Mutational analysis of the role of His452 of Saccharopolyspora rectivirgula beta-galactosidase

To examine the role of His452 of the Saccharopolyspora rectivirgula beta-galactosidase in the binding of a tightly bound, catalytically important Mn2+ (i.e., class II Mn2+) ion, His452 was replaced with Phe or Glu and the respective site-directed mutants, H452F and H452E, were characterized. Neither mutant contained Mn2+ in an Mn2+-free buffer and both were virtually inactive in the absence of Mn2+ (their relative activities being less than 0.03% that of the fully activated wild-type enzyme). When Mn2+ was added, however, the mutants were activated to 3% (for H452F) and 0.8% (for H452E) of the full activity of the wild type. The Mn2+ concentrations needed for half-maximal activation of H452F and H452E were, respectively, 15,000 and 5000 times higher than the reported dissociation constant (2 nM) of the class II Mn2+, suggesting that His452 plays a key role in the binding of this catalytically important Mn2+. Activation of the mutants by Mn2+, albeit very weak, contrasts with a lack of any such metal activation previously observed with the two corresponding mutants of Escherichia coli lacZ beta-galactosidase.

Thermostable collagenolytic activity of a novel thermophilic isolate, Bacillus sp. strain NTAP-1

We isolated an acidophilic thermophile belonging to the genus Bacillus, strain NTAP-1, which secreted a thermostable collagenolytic activity into the culture medium. The collagenolytic activity exhibited an optimum pH for Azocoll hydrolysis of pH 3.9 and was not completely inhibited by 10 mM ethylenediaminetetraacetic acid (residual activity, 63%), suggesting that Bacillus NTAP-1 produces a novel acid proteinase with highest activity for collagen. The collagenolytic activity was thermostable; more than 80% of the original activity was retained after incubation of the culture supernatant at pH 4.0 and 60 degrees C for 4 h.

Dietary zinc deficiency decreases glutathione S-transferase expression in the rat olfactory epithelium

Zinc deficiency leads to olfactory and gustatory dysfunction, but little is known about the underlying molecular mechanism of this phenomenon. We examined the effect of dietary zinc deficiency on the rat olfactory epithelium. Immunoreactivities of glutathione S-transferase (GST) mu, neuron-specific enolase (NSE) and proliferating cell nuclear antigen (PCNA), and in situ hybridization of GST mu mRNA in the olfactory epithelia were examined under different dietary zinc intake conditions. Adult male rats were fed a zinc-deficient (ZD) diet (0.5 mg zinc/kg diet), whereas control rats, including pair-fed (PF) and zinc-adequate (ad libitum consumption, AL) groups, were fed a zinc-adequate diet (58 mg zinc/kg diet) for 7 wk. We also examined the effect of zinc replacement (ZR) by subsequently feeding half of the ZD group a zinc-adequate diet for 5 wk after the initial 7-wk deprivation. No significant differences in immunoreactivity for NSE in olfactory epithelial receptor cells or for PCNA in basal cells were noted among groups. Intense GST mu immunoreactivity and hybridization signals were observed in olfactory supporting cells of AL, PF and ZR groups, but very minimal or no such signal was noted in ZD rats. Our findings indicated that zinc deficiency reduces GST mu expression in the supporting cells of rat olfactory epithelia but does not affect receptor cell proliferation or maintenance.

Effects of tongue electrical stimulation on pharyngeal mechanics in anaesthetized patients with obstructive sleep apnoea

The tongue plays a significant role in the maintenance of a patent airway. The purpose of this study was to examine the effects of tongue musculature contraction on the static mechanical properties of the pharynx in patients with obstructive sleep apnoea (OSA). During hyperventilation-induced apnoea in seven OSA patients anaesthetized with sevoflurane, the static pressure/area relationships of the oropharynx were obtained by means of step changes in airway pressure while endoscopically measuring cross-sectional area. At each airway pressure, the tongue was electrically stimulated via electrodes placed bilaterally. Tongue electrical stimulation (TES) did not further dilate the oropharyngeal area at higher airway pressure (3.2+/-1.9 versus 3.0+/-2.1 cm2), although the narrowed oropharyngeal area at lower airway pressures increased during TES (0.8+/-9.0) versus 1.7+/-1.8 cm2, p<0.05). Accordingly, the slope of the pressure/area relationship decreased during TES (0.24+/-0.20 versus 0.12+/-0.09 cm2 x cm H2O(-1), p<0.05). In conclusion, electrical stimulation of the tongue stiffens the retroglossal airway wall in patients with obstructive sleep apnoea.

Experimental pain augments experimental dyspnea, but not vice versa in human volunteers

BACKGROUND

Pain and dyspnea frequently coexist in many clinical situations. However, whether the two different symptoms interact with each other has not been elucidated. To elucidate the interaction between pain and dyspneic sensations, the authors investigated separately the effects of pain on dyspnea and the effects of dyspnea on pain in 15 healthy subjects.

METHODS

Subjects were asked to rate their sensation of pain or dyspnea using a visual analog scale (VAS) during pain stimulation produced by tourniquet inflation (inflation cuff pressure: 350 mmHg) around the calf, and/or the respiratory loading consisted of a combination of resistive load (77 cm H2O x l(-1) x s(-1)) and hypercapnia induced by extra mechanical dead space (255 ml). In addition to changes in VAS scores, changes in ventilatory airflow and airway pressure were continuously measured.

RESULTS

Pain stimulation and loaded breathing increased VAS scores, ventilation, and occlusion pressure (P0.1). The addition of a pain stimulus during loaded breathing increased the dyspneic VAS score (median 56 [interquartile range 50-62] vs. 64 [55-77]: before vs. after addition of pain stimulus, P < 0.05) with concomitant increases in minute ventilation (10.8 [10.1-13.3] vs. 12.4 [11.0-14.8] l/min, P < 0.05) and P0.1 (5.5 [4.9-7.2] vs. 6.8 [5.8-9.0] cm H2O, P < 0.05). The addition of respiratory loading during pain stimulation did not cause a significant change in pain VAS score (40 [33-55] vs. 31 [30-44]: before vs. after addition of respiratory loading), although both additional burdens increased further minute ventilation (10.0 [8.8-10.9] vs. 12.0 [10.6-13.2] l/min, P < 0.05) and P0.1 (2.5 [2.0-3.0] vs. 6.2 [4.9-7.0] cm H2O, P < 0.05).

CONCLUSION

The authors' findings suggest that pain intensifies the dyspneic sensation, presumably by increasing the respiratory drive, whereas dyspnea may not intensify the pain sensation.

Inhibition of neuronal nitric oxide synthase by phosphatidylinositol 4,5-bisphosphate and phosphatidic acid

Phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidic acid (PA) were found to inhibit strongly the citrulline formation activity of neuronal nitric oxide synthase (nNOS; EC 1.14.13.39). Such inhibition was not observed with any other phospholipid examined. A kinetic analysis of purified nNOS showed no significant change in apparent K(m) for L-Arg or NADPH caused by these inhibitory phospholipids. Electron paramagnetic resonance analysis revealed no significant spectral perturbation of the ferriheme or flavin semiquinone upon the addition of PIP2. On the other hand, a lower enhancement of the NADPH diaphorase activity by Ca(2+)-calmodulin was observed in the presence of PIP2 and PA, and the citrulline formation activity was protected from phospholipid inhibition by preincubation with Ca(2+)-calmodulin. Moreover, trypsin digestion analysis showed that the cleavage site within the calmodulin-binding site of nNOS was specifically protected from trypsin by the addition of PIP2 and PA. These results strongly suggest that PIP2 and PA inhibit the citrulline formation activity of nNOS by blocking the interaction of the enzyme with Ca(2+)-calmodulin.

An endothelial nitric oxide synthase inhibitor aggravates CDL-induced acute pancreatitis in rats

To clarify the role of nitric oxide (NO) in the development and progression of acute pancreatitis, we investigated the effect of different NO synthase inhibitors and NO donors on experimental pancreatitis in rats. Closed duodenal loop (CDL)-induced pancreatitis was produced in male Wistar rats, and the animals were treated with normal saline, the NO-synthase substrate L-arginine, the NO donor S-nitroso-N-acetylpenicillamine, aminoguanidine, which is a more powerful inhibitor of inducible NO synthase (iNOS) than is endothelial NO synthase (eNOS), and N-nitro-L-arginine methyl ester (L-NAME), a more powerful inhibitor of eNOS than of iNOS. All drugs were infused intravenously during a period of 6 or 12 h in each group. Pancreatic tissue was removed at 6 and 12 h after creating the CDL. L-Arginine, S-nitroso-N-acetyl-penicillamine, and aminoguanidine treatment had no effect on the elevation of serum pancreatic enzymes, whereas L-NAME administration significantly exacerbated their elevation. Pathologically, L-NAME treatment resulted in a significantly worse histologic score at 6 and 12 h, especially in terms of the degree of hemorrhage, acinar cell necrosis, and microvascular thrombosis. Addition of L-arginine clearly reversed the effect of L-NAME. Neither the NO substrate nor NO donor could inhibit the progression of hemorrhagic pancreatitis in CDL-induced pancreatitis. Aminoguanidine had no effect on the severity of the pancreatitis. We therefore concluded that NO production by eNOS may play a significant role in preventing the development and progression of acute pancreatitis.

Association of mast cells with Warthin's tumor in fine needle aspirates of the salivary gland

OBJECTIVE

To determine the significance of the presence of mast cells in Warthin's tumor by evaluating the occurrence of these cells in cellular and immunohistochemical preparations.

STUDY DESIGN

Specimens derived from five cases of FNAC were examined. A total of four slides from five cases were prepared from each: two air-dried smears were stained with May-Grünwald-Giemsa (MGG) stain and two with Hansel's stain. The other two were alcohol fixed and stained using the Papanicolaou method. The smears were evaluated for the presence of mast cells, especially associated with oxyphilic cells. In order to investigate the location of mast cells, we also counted those cells by means of immunohistochemistry using anti-mast cell monoclonal antibody AA1.

RESULTS

The Hanselstained cellular sample from Warthin's tumor contained numerous mast cells, associated mainly with large, oxyphilic cell sheets. The number of AA1-positive cells (mast cells) stained with immunohistochemistry was greater in epithelial component than in lymphoid stroma.

CONCLUSION

Mast cells in a salivary gland aspirate might be indicative of Warthin's tumor; therefore, MGG-stained slides offer the advantage of ease of preparation, particularly when the typical cytologic features are not present.

Binding analysis of Xenopus laevis translation initiation factor 4E (eIF4E) in initiation complex formation

A translation initiation factor, eIF4E, of Xenopus laevis was purified by affinity column chromatography after the gene expression as a full-length protein in a baculovirus-insect cell system. Interaction between X. laevis eIF4E and 4E-BP2 was analyzed by affinity column chromatography, gel permeation chromatography (GPC), and surface plasmon resonance (SPR). It was found that the interaction of eIF4E with an mRNA cap-analogue enhanced the binding activity of eIF4E with 4E-BP2. Furthermore, the SPR analysis showed that the eIF4E-cap-analogue interaction was very weak regardless of complex formation of 4E-BP2 with eIF4E; the dissociation constant of eIF4E for the cap-analogue was estimated to be 10(-2)-10(-4) M. These results suggest that the participation of another initiation factor is required for eIF4E to recognize the cap structure in vivo. The results reported in this paper support "the performed complex model" of Lee et al., in which eIF4E binds to the mRNA cap structure after the initiation factors have formed the initiation complex eIF4F.

Crystal structure of a multifunctional 2-Cys peroxiredoxin heme-binding protein 23 kDa/proliferation-associated gene product

Heme-binding protein 23 kDa (HBP23), a rat isoform of human proliferation-associated gene product (PAG), is a member of the peroxiredoxin family of peroxidases, having two conserved cysteine residues. Recent biochemical studies have shown that HBP23/PAG is an oxidative stress-induced and proliferation-coupled multifunctional protein that exhibits specific bindings to c-Abl protein tyrosine kinase and heme, as well as a peroxidase activity. A 2.6-A resolution crystal structure of rat HBP23 in oxidized form revealed an unusual dimer structure in which the active residue Cys-52 forms a disulfide bond with conserved Cys-173 from another subunit by C-terminal tail swapping. The active site is largely hydrophobic with partially exposed Cys-173, suggesting a reduction mechanism of oxidized HBP23 by thioredoxin. Thus, the unusual cysteine disulfide bond is involved in peroxidation catalysis by using thioredoxin as the source of reducing equivalents. The structure also provides a clue to possible interaction surfaces for c-Abl and heme. Several significant structural differences have been found from a 1-Cys peroxiredoxin, ORF6, which lacks the C-terminal conserved cysteine corresponding to Cys-173 of HBP23.

[A case of mixed connective tissue disease with microscopic polyarteritis nodosa associated with perinuclear-antineutrophil cytoplasmic antibody and anti-glomerular basement membrane]

A 46-year-old female was admitted to our hospital due to general fatigue, systemic edema and dyspnea with history of systemic sclerosis (SSc). The patient was diagnosed as mixed connective tissue disease (MCTD) based on Raynaud phenomenon, a high anti-RNP antibody level and clinical symptoms and laboratory findings suggesting SSc, dermatomyositis (DM) and systemic lupus erythematosus (SLE). After the admission, both alveolar hemorrhage and a rapidly progressive glomerulonephritis (RPGN) also developed and laboratory findings showed a positive remark of myeloperoxydase-antineutrophil cytoplasmic antibody (MPO-ANCA) and anti-glomerular basement membrane (GBM) antibody. She was therefore re-diagnosed as microscopic polyarteritis nodosa (microscopic PAN) combined with MCTD and treatment with high dose prednisolone and steroid pulse therapy dramatically improved general conditions and lung symptoms, but maintenance dialysis was persistent because of irreversible renal failure. However, 3 months after the admission, she died of acute exacerbation of interstitial pneumonitis that was unresponsive to steroid pulse therapy. Autopsy revealed interstitial pneumonitis with alveolar hemorrhage and crescentic glomerulonephritis (CrGN), in which immunofluorescent microscopy showed no deposition in agreement with pauciimmune type. The histological findings supported the diagnosis; primary microscopic PAN combined with MCTD, which is a quite rare case, to our knowledge. Furthermore, co-existence of MPO ANCA and anti-GBM antibody, clinical and histological findings of the case also lead us to reconsider the relevance of these antibodies to pathogenesis and/or categories of microscopic PAN and Goodpasture's syndrome.

Inhibition of the generation of thrombin and factor Xa by a fucoidan from the brown seaweed Ecklonia kurome

The effects of a fucoidan (C-II), which was purified from the brown seaweed Ecklonia kurome, on the generation of thrombin and factor Xa have been investigated by measuring the amidolytic activities by using the respective specific chromogenic substrates in both plasma and purified systems. C-II inhibited significantly the generation of thrombin in both the intrinsic and the extrinsic pathways, although the intrinsic inhibitory effect by C-II was more remarkable than the extrinsic one. On the other hand, C-II was a good inhibitor of the factor Xa generation in the intrinsic pathway, while it was a poor one in the extrinsic pathway. In the purified systems C-II also inhibited the formation of prothrombin-activating complex (i.e., prothrombinase), but not its activity. The concentration of C-II required for 50% inhibition of thrombin generation was about one-tenth to one-seventh of that of the activity of the generated thrombin in plasma. These results indicate that C-II has an inhibitory effect on the generation of thrombin by blocking the formation of prothrombinase and by preventing the generation of intrinsic factor Xa in addition to its antithrombin activity, and also that the generation-inhibitory effect is more remarkable than C-II's enhancement effect on the antithrombin activity by heparin cofactor II in plasma.

Topological analysis of an RND family transporter, MexD of Pseudomonas aeruginosa

The membrane topology of a resistance-nodulation-division (RND) family transporter, MexD of Pseudomonas aeruginosa, was determined. Although it had been predicted previously that most RND proteins contain 12 transmembrane helices, three independent computer programs used in the present study predicted that MexD possessed 11, 14 or 17 transmembrane segments. To investigate the topology of MexD more thoroughly, 25 MexD-PhoA (alkaline phosphatase) and 18 MexD-Bla (beta-lactamase) fusion plasmids were constructed and analyzed. The resulting topological model had just 12 transmembrane helices and two periplasmic loops of about 300 residues between helices 1 and 2 and helices 7 and 8. It is therefore proposed that the N- and C-termini are located in the cytoplasm and the predicted orientation is consistent with the 'positive-inside rule'. This topological model can be applied to other RND proteins.

Nitrous oxide increases normocapnic cerebral blood flow velocity but does not affect the dynamic cerebrovascular response to step changes in end-tidal P(CO2) in humans

We sought to clarify the effect of nitrous oxide (N2O) on the immediate responses of cerebral vasculature to sudden changes in arterial carbon dioxide tension in healthy humans. By use of a transcranial Doppler ultrasonography, blood flow velocity in the middle cerebral artery (V(MCA)) was measured during a step increase followed by a step decrease in end-tidal CO2 tension (PET(CO2)) between normo- and hypercapnia while subjects inspired gas mixtures containing 70%O2 + 30% N2 (control) and 70% O2 + 30% N2O (N2O) separately. During the control condition, both step increase and decrease in PET(CO2) produced rapid exponential changes in V(MCA). An increase in V(MCA) produced by the step increase in PET(CO2) was smaller (P < 0.001) and slower (P < 0.001) than a decrease in V(MCA) induced by the step decrease in PET(CO2). These general features of the dynamic cerebrovascular response were not affected by substitution of N2O for N2 in the inspired gases although N2O increased baseline V(MCA) by 15% (P < 0.001) compared with the control condition. We conclude that N2(O) in itself does not affect the dynamic cerebrovascular response to arterial CO2 changes, although it produces static mild cerebral vasodilation.

IMPLICATIONS

This study suggests that nitrous oxide does not affect the dynamic cerebrovascular reactivity to acute arterial carbon dioxide (CO2) changes, i.e., exponential changes in cerebral blood flow in response to step changes in alveolar CO2 tension, although it does produce a mild increase in normocapnic cerebral blood flow velocity.

Diazepam increases calcium sensitivity of the skinned cardiac muscle fiber in guinea pig

Influences of diazepam, a benzodiazepine derivative, on the contractile response to calcium in skinned trabecular fibers of guinea pig heart were examined. Diazepam (100 microM) enhanced the contractile response of the skinned fiber to calcium and shifted the concentration-response curve to the left. The pCa50 values were 6.07+/-0.03 and 6.28+/-0.03 (P<0.05) in the absence and presence of diazepam, respectively. This result suggests that diazepam increases calcium sensitivity of contractile proteins in heart muscles.

Protein design of geranyl diphosphate synthase. Structural features that define the product specificities of prenyltransferases

Geranyl diphosphate synthase catalyzes the condensation of isopentenyl diphosphate with dimethylallyl diphosphate to give a C(10) compound, geranyl diphosphate, which is a precursor of all monoterpenoids. However, the gene has not been isolated from any organisms. To examine the possibility that geranyl diphosphate synthase has evolved from a common ancestor of the prenyltransferase family and to predict the active site structure, we tried to convert Bacillus stearothermophilus farnesyl diphosphate synthase to geranyl diphosphate synthase, according to our previous findings. Several mutated farnesyl diphosphate synthases that have single amino acid substitutions before the first aspartate-rich motif were constructed. A mutated enzyme that has the replacement of serine by phenylalanine at the fourth position before the motif exclusively produced geranyl diphosphate when dimethylallyl diphosphate was used as the primer, and hardly accepted geranyl diphosphate as a primer, indicating that this mutation causes the conversion to geranyl diphosphate synthase. This result supports the idea that the product specificities of all members of the E-prenyltransferase family are mainly defined by a few structural features: the amino acids at the fourth position and the fifth position before the first aspartate-rich motif, and the insertion of two amino acids in the motif. This suggests that natural geranyl diphosphate synthases might have an active site structure similar to that of the mutated enzyme.

Sleep-disordered breathing in acromegalics--relation of hormonal levels and quantitative sleep study by means of bedside oximeter

Sleep-disordered breathing (SDB) is common in patients with growth hormone (GH) secreting pituitary adenomas. Since long-term untreated SDB aggravates systemic conditions (hypertension and arrhythmia etc.), the therapeutic outcome of SDB is important in reducing morbidity and mortality rates. But the results of a quantitative analysis of the lowered GH and IGF-1 levels in SDB in a relatively large number of patients are not detailed. Ten consecutive acromegalic patients were studied with a bedside oximeter. Preoperatively they were divided into two groups based on the presence (SDB group = 6 patients) or absence (non-SDB group = 4 patients) of clinical symptoms of SDB such as habitual snoring, excessive daytime somnolence and nocturnal apneic episodes. The serum IGF-1 averaged 931.7 ng/ml in SDB group and 898.3 ng/ml in non-SDB group. The oxygen desaturation index (ODI) (the number of oxygen desaturations exceeding 4% from the base line) was 29.1+/-15.4 in the SDB group and 2.5+/-1.8 in the non-SDB group (P=0.01). Other oximeter parameters such as the percent of the time spent at O2 saturation < 90% and the mean and the lowest O2 saturations closely correlated with the degree of the clinical symptoms. A postoperative sleep study was conducted in 5 patients in the preoperative SDB group, 4 months or more after the surgery. The serum GH and IGF-1 levels normalized in 3 patients but remained slightly high in 2. ODI became 9.1+/-5.6, which was significantly lower than the preoperative value (P=0.026). One patient had a complete clinical resolution. The other 4 obtained slight to moderate improvement clinically and oximetrically despite normalized or decreased hormonal levels. This study clarified that the response of SDB to lowering of the GH level varies from one patient to another and persisting SDB despite the normalization of the hormonal levels suggests the involvement of other factors in the production of SDB.

[In vitro antibacterial activity of faropenem, a novel oral penem antibiotic, against enterohemorrhagic Escherichia coli O157 strains]

Against enterohemorrhagic Escherichia coli (EHEC) O157 clinically isolated, the effects of faropenem (FRPM), a novel oral penem antibiotic, on the MICs, bactericidal activity, verotoxin (VT)-release, and lipopolysaccharide (LPS)-release were investigated in vitro and compared with those of other types of antibacterial agents. The MICs of FRPM in aerobic and anaerobic culture condition, were 0.78 and 0.39 microgram/ml, respectively. In aerobic condition, FRPM was more active than ampicillin, amoxicillin (AMPC), fosfomycin (FOM), kanamycin (KM), minocycline (MINO), and clarithromycin (CAM), but was slightly less active than cefdinir (CFDN), cefditoren (CDTR), and norfloxacin (NFLX) against O157 clinical isolates. In anaerobic condition, however, FRPM showed as strong activity as CFDN, CDTR, and NFLX. FOM, NFLX, and KM as well as the beta-lactams including FRPM indicated the powerful bactericidal activity against one strain of O157 clinical isolates. The effects of MINO and CAM were bacteriostatic. FOM and the beta-lactams including FRPM promoted verotoxin type 1 (VT1)-release, but rather suppressed verotoxin type 2 (VT2)-release from the same isolate. NFLX, however, promoted VT1-release and vast amount of VT2-release. In the case of KM, MINO, and CAM, the release suppression of both VT1 and VT2 was observed. FRPM, AMPC, and FOM had very weak activity on LPS-release, while CFDN, CDTR, and NFLX released a large amount of LPS from the strain. KM, MINO, and CAM had relatively weak activity. In these in vitro experiments, FRPM demonstrated the effective profile to the treatment for EHEC infection, except for the effect on VT1-release. These results suggest the possibility that FRPM shows good clinical efficacy for EHEC infection.

Collapsibility of passive pharynx in patients with acromegaly

Sleep-disordered breathing (SDB), either central or obstructive in nature, is common in patients with acromegaly. However, no study has systematically examined the collapsibility of the pharynx in acromegaly to date. We evaluated intrinsic mechanical properties of passive pharynx in 10 anesthetized and paralyzed patients with active acromegaly before transsphenoidal adenomectomy for their pituitary adenoma. Static pressure-area relationships of the velopharynx and oropharynx were obtained by step changes in airway pressure during endoscopic cross-sectional area measurement of each segment. Moreover, curve fitting analysis by an exponential function estimated the closing pressure (P'close) of each segment. Preoperative nocturnal oximetry identified five acromegalic patients with an oxygen desaturation index (ODI) greater than 10 h-1 and clinical symptoms suggesting presence of SDB. The pharyngeal airway of all five acromegalic patients with SDB was highly collapsible at both velopharynx and oropharynx with positive P'close. Compared with age-, body mass index (BMI)-, and ODI-matched SDB patients without acromegaly, SDB patients with acromegaly had a higher P'close of the oropharynx, indicating that the etiology of SDB in acromegaly appears to differ from that of ordinary sleep apnea. Our results suggest that anatomic abnormality, especially at the base of the tongue, appears to play a significant role in development of SDB in acromegaly.

Atypical presentation of vertebral bone metastasis from lung cancer

The authors describe a case of lung cancer in a 55-year-old man who complained of back pain. Initial isotopic bone scanning showed no abnormality, however, magnetic resonance (MRI) imaging revealed bone metastasis in thoracic vertebral bone. Even when there is no typical findings of metastasis in bone scintigraphy, MRI imaging would be useful if vertebral bone metastasis is suspected. MRI imaging is an important modality to evaluate extraosseous extension and marrow invasion of metastatic tumors.

Characterization of mouse nNOS2, a natural variant of neuronal nitric-oxide synthase produced in the central nervous system by selective alternative splicing

Mouse neuronal nitric-oxide synthase 2 (nNOS2) is a unique natural variant of constitutive neuronal nitric-oxide synthase (nNOS) specifically expressed in the central nervous system having a 105-amino acid deletion in the heme-binding domain as a result of in-frame mutation by specific alternative splicing. The mouse nNOS2 cDNA gene was heterologously expressed in Escherichia coli, and the resultant product was characterized spectroscopically in detail. Purified recombinant nNOS2 contained heme but showed no L-arginine- and NADPH-dependent citrulline-forming activity in the presence of Ca2+-promoted calmodulin, elicited a sharp electron paramagnetic resonance (EPR) signal at g = 6.0 indicating the presence of a high spin ferriheme as isolated and showed a peak at around 420 nm in the CO difference spectrum, instead of a 443-nm peak detected with the recombinant wild-type nNOS1 enzyme. Thus, although the heme domain of nNOS2 is capable of binding heme, the heme coordination geometry is highly abnormal in that it probably has a proximal non-cysteine thiolate ligand both in the ferric and ferrous states. Moreover, negligible spectral perturbation of the nNOS2 ferriheme was detected upon addition of either L-arginine or imidazole. These provide a possible rational explanation for the inability of nNOS2 to catalyze the cytochrome P450-type monooxygenase reaction.

Association of plasma fibrinogen level and blood pressure with diabetic retinopathy, and renal complications associated with proliferative diabetic retinopathy, in Type 2 diabetes mellitus

AIM

To clarify the association of several clinical parameters, including plasma fibrinogen level, with diabetic retinopathy in patients with Type 2 diabetes mellitus (DM).

METHODS

A total of 294 Japanese patients with Type 2DM were studied; 53 patients with no diabetic retinopathy (NDR), 90 with background diabetic retinopathy (BDR), and 151 with proliferative diabetic retinopathy (PDR). Multiple logistic regression analysis was performed to assess variables independently associated with diabetic retinopathy in two settings: presence of retinopathy of any severity and presence of advanced retinopathy.

RESULTS

The following parameters were identified as independent factors associated with the presence of diabetic retinopathy (NDR vs. BDR + PDR): type of therapy (P<0.0005), log-transformed plasma fibrinogen level (P < 0.05), mean blood pressure (P < 0.05), and duration of diabetes (P < 0.05). The independent variables associated with advanced retinopathy were type of therapy (P<0.00005), age (P<0.0005) and nephropathy (P<0.05). Body mass index, smoking and hypertensive status, HbA1c and total cholesterol levels were not independently associated.

CONCLUSIONS

These data suggest that in patients with Type 2 DM, an increased blood viscosity due to high fibrinogen level as well as an elevated intravessel pressure play a role in the development of diabetic retinopathy, and that the progression to PDR is influenced or accompanied by the deterioration of renal status.

Coordination of swallowing and phases of respiration during added respiratory loads in awake subjects

In order to test the hypothesis that different types of respiratory mechanical loads may differently modify the coordination of respiration and swallowing, we investigated the coordination of respiration and swallowing during resistive and elastic loads in 14 healthy subjects. Ventilation was monitored with a pneumotachograph and reflex swallowing was elicited by continuous infusion of distilled water into the pharynx (3 ml/min) and recorded on a submental electromyogram while the subject breathed through a device with a flow-resistive load (180 cm H2O/L/s), an elastic load (70 cm H2O/L), or without any external load. We found that addition of a flow-resistive load did not influence the frequency of swallowing, whereas addition of an elastic load caused a significant increase in swallowing frequency during continuous infusion of water. Analysis of the timing of swallowing in relation to respiratory cycle phase revealed that with flow-resistive loading, swallows occurred preferentially during the inspiratory-expiratory (I-E) transition, whereas with elastic loading, swallows occurred preferentially during the expiratory-inspiratory (E-I) transition. Signs of laryngeal irritation were observed most often during the elastic loading following E-I swallows. These results indicate that different types of respiratory mechanical loads can differently modify this coordination of respiration and swallowing, and suggest that the coordination may be compromised more with elastic loading than with flow-resistive loading.

Crystallographic characterization of a stress-induced multifunctional protein, rat HBP-23

HBP-23 is a stress-induced multifunctional rat protein that belongs to a novel family of antioxidant proteins, referred to as peroxiredoxins, and exhibits heme-binding and inhibition of c-Abl protein tyrosine kinase. Recombinant HBP-23 was crystallized by a hanging-drop vapor-diffusion method. The crystals belong to space group P41212 or P43212 with unit-cell dimensions of a = b = 73.47 A, c = 210.37 A and contain two protein molecules in the asymmetric unit. A data set at 2.7-A resolution was collected with a cryo-crystallographic technique. Crystals of selenomethionyl HBP-23 were also obtained under the same conditions.

Molecular cloning and characterization of the oprQ gene coding for outer membrane protein OprE3 of Pseudomonas aeruginosa

We cloned and characterized the oprQ gene coding for outer membrane protein OprE3 of Pseudomonas aeruginosa PAO1. The oprQ gene was composed of 1,275 base pairs including a sequence encoding for the signal sequence and a mature protein with a Mr of 44,602. Computer-aided alignment and hydropathy analyses of the predicted amino acid sequences suggested that OprE3 is a transmembrane protein homologous to outer membrane proteins of P. aeruginosa such as OprD2 (OprD) porin and OprE1 (OprE) porin. Susceptibility to several antibiotics of the strains lacking or overproducing OprE3 was indistinguishable from that of the wild-type strain, suggesting that OprE3 is unlikely involved in the diffusion of carbapenems and other beta-lactam antibiotics.

Efficacy of endoscopic static pressure/area assessment of the passive pharynx in predicting uvulopalatopharyngoplasty outcomes

OBJECTIVES/HYPOTHESIS

Although uvulopalatopharyngoplasty (UPPP) is an attractive surgical treatment for obstructive sleep apnea (OSA), the unpredictable outcome limits application of the procedure. Since UPPP corrects only retropalatal airway (RP) patency, we hypothesized that response to UPPP is determined by collapsibility of the retroglossal airway (RG), where UPPP does not correct.

METHODS

We estimated closing pressure (Pclose) for each pharyngeal segment by endoscopically obtaining the static pressure/area relationship of the passive pharynx in completely paralyzed and anesthetized patients with sleep-disordered breathing (n = 41) before UPPP. Preferable response to UPPP was defined as the number of oxygen dips (ODI), obtained by nocturnal oximetry, less than 10 h(-1) after UPPP.

RESULTS

Patients with negative Pclose at RG responded to UPPP significantly better than those with positive Pclose at RG (22/30 [73%] vs. 3/11 [27%], P<.05). ODI after UPPP was significantly correlated with age, Pclose at RP, and Pclose at RG.

CONCLUSIONS

Endoscopic assessment of anatomic abnormality of the pharynx in paralyzed patients with sleep-disordered breathing under general anesthesia has clinical value for the improvement of UPPP outcome.

Sequence analysis of the gyrA and parC homologues of a wild-type strain of Vibrio parahaemolyticus and its fluoroquinolone-resistant mutants

Vibrio parahaemolyticus causes seafood-borne gastroenteritis in humans. It is particularly important in Japan, where raw seafood is frequently consumed. Fluoroquinolone is one of the current drugs of choice for treating patients infected by V. parahaemolyticus because resistant strains are rarely found. To study a possible fluoroquinolone resistance mechanism in this organism, nucleotide sequences that are homologous to known gyrA and parC genes have been cloned from V. parahaemolyticus AQ3815 and sequenced by amplification with degenerate primers of the quinolone resistance-determining region (QRDR), followed by cassette ligation-mediated PCR. Open reading frames encoding polypeptides of 878 and 761 amino acid residues were detected in the gyrA and parC homologues, respectively. The V. parahaemolyticus GyrA and ParC sequences were most closely related to Erwinia carotovora GyrA (76% identity) and Escherichia coli ParC (69% identity) sequences, respectively. Ciprofloxacin-resistant mutants of AQ3815 were obtained on an agar medium by multistep selection with increasing levels of the quinolone. One point mutation only in the gyrA QRDR was detected among mutants with low- to intermediate-level resistance, while point mutations in both the gyrA and parC QRDRs were detected only in strains with high-level resistance. These results strongly suggest that, as in other gram-negative bacteria, GyrA and ParC are the primary and secondary targets, respectively, of ciprofloxacin in V. parahaemolyticus.

A thermophilic cyanobacterium Synechococcus elongatus has three different Class I prenyltransferase genes

Prenyltransferases (prenyl diphosphate synthases), which are a broad group of enzymes that catalyze the consecutive condensation of homoallylic diphosphate of isopentenyl diphosphates (IPP, C5) with allylic diphosphates to synthesize prenyl diphosphates of various chain lengths, have highly conserved regions in their amino acid sequences. Based on the above information, three prenyltransferase homologue genes were cloned from a thermophilic cyanobacterium, Synechococcus elongatus. Through analyses of the reaction products of the enzymes encoded by these genes, it was revealed that one encodes a thermolabile geranylgeranyl (C20) diphosphate synthase, another encodes a farnesyl (C15) diphosphate synthase whose optimal reaction temperature is 60 degrees C, and the third one encodes a prenyltransferase whose optimal reaction temperature is 75 degrees C. The last enzyme could catalyze the synthesis of five prenyl diphosphates of farnesyl, geranylgeranyl, geranylfarnesyl (C25), hexaprenyl (C30), and heptaprenyl (C35) diphosphates from dimethylallyl (C5) diphosphate, geranyl (C10) diphosphate, or farnesyl diphosphate as the allylic substrates. The product specificity of this novel kind of enzyme varied according to the ratio of the allylic and homoallylic substrates. The situations of these three S. elongatus enzymes in a phylogenetic tree of prenyltransferases are discussed in comparison with a mesophilic cyanobacterium of Synechocystis PCC6803, whose complete genome has been reported by Kaneko et al. (1996).