The combined associations of social participation and support with self-rated health and dietary satisfaction in men with spinal cord injury.

STUDY DESIGN: Cross-sectional study. OBJECTIVES: (1) To examine the association between social participation (SP) and social support (SS) with self-rated health and dietary satisfaction and (2) to explore the joint association and interactions of SP and SS with self-rated health and dietary satisfaction in community-dwelling adult men with spinal cord injury. SETTING: Members of the Spinal Injuries Japan organization. METHODS: We sent questionnaires to 2731 registered members of Spinal Injuries Japan via mail. Responses from 625 men aged ⩾40 years were analyzed. Respondents were categorized into four groups: SP/sufficient SS, SP/insufficient SS, no SP/sufficient SS and no SP/insufficient SS. Logistic regression analysis was used to examine the odds ratios for self-rated health and dietary satisfaction according to the SP/SS categories. RESULTS: Relative to participants in the no SP/insufficient SS category, those in the SP/sufficient SS group demonstrated significantly better self-rated health and dietary satisfaction after adjusting for sociodemographic variables. There was no interaction between SP and SS in self-rated health or dietary satisfaction. SP was associated with high self-rated health without SS, and sufficient SS was associated with high dietary satisfaction without SP. CONCLUSIONS: Relative to other groups, participants with SP/sufficient SS demonstrated higher self-rated health and dietary satisfaction. Sufficient SS was associated with high dietary satisfaction without SP. This study suggested the importance of addressing aspects of both SP and SS using self-rated health and dietary satisfaction as outcome measures in health promotion programs.

Transient induction of the MRP/GS-X pump and gamma-glutamylcysteine synthetase by 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3- nitrosourea in human glioma cells.

Treatment of human glioma A172 cells with 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU), an alkylating antitumor agent the primary target of which has been thought to be DNA, resulted in elevated expression of mRNA for multidrug resistance-associated protein (MRP) within the first 2 h and then a decrease in expression 24 h after the treatment. Western blot analyses revealed that levels of MRP in these ACNU-treated cells paralleled mRNA levels. Membrane vesicles prepared from ACNU-treated cells also displayed elevated transport activities for leukotriene C4, a known substrate for MRP. Gamma-glutamylcysteine synthetase (gamma-GCS) mRNA expression was coinduced with MRP by ACNU. Because gamma-GCS is the rate-limiting enzyme involved in the de novo biosynthesis of glutathione, increases in glutathione were also transiently induced by ACNU. These results demonstrate for the first time that the expression of functional MRP and gamma-GCS can be transiently coinduced by ACNU. Multiple short exposures (1 h) of ACNU following a long duration (1 week) of drug-free conditions resulted in the development of an ACNU-resistant population (designated A172R) that overexpressed MRP/gamma-GCS mRNA and had elevated transport activities for leukotriene C4. A172R exhibited cross-resistance to the antitumor drug doxorubicin and heavy metal sodium arsenate but not to cisplatin. Our results also demonstrate that intermittent treatments of human glioma cells with ACNU can lead to the development of MRP-related multidrug resistance. These results, taken together, reveal a possible new mechanism of the development of drug resistance for the antitumor nitrosoureas.

Interaction of wasp venom mastoparan with biomembranes.

Mastoparan-induced changes in the K+ permeability of rat peritoneal mast cells, human erythrocytes, Staphylococcus aureus and Escherichia coli were examined. Mastoparan did not efficiently increase the K+ permeability of cells except for S. aureus. The release of membrane phospholipids was also observed from S. aureus cells in the concentration range of the permeability enhancement. Mastoparan stimulated histamine release from mast cells, independently of a small efflux of K+. Mastoparan became markedly effective to E. coli cells whose outer membrane structure was chemically disrupted beforehand, showing that the peptide can enhance the permeability of the cytoplasmic membranes of both Gram-positive and -negative bacteria. In experiments using liposomes, mastoparan increased the permeability of the liposomes composed of egg phosphatidylethanolamine and egg phosphatidylglycerol, which are the lipid constituents of the cytoplasmic membrane of E. coli cells, while it showed a weak activity to the liposomes composed of egg phosphatidylcholine and cholesterol. The latter result related closely to the fact that this peptide acted weakly on erythrocytes and mast cells in which acidic lipids constitute a minor portion. Mastoparan decreased the phase transition temperature of dipalmitoylphosphatidylglycerol liposomes, but it did not affect that of dipalmitoylphosphatidylcholine liposomes. These results indicate that mastoparan penetrated into membranes mainly containing acidic phospholipids and disrupted the membrane structure to increase the permeability. The action of the wasp venom mastoparan was compared with that of a bee venom melittin.

Recessive nonsense suppressors in Saccharomyces cerevisiae: action spectra, complementation groups and map positions.

Three genes SUP111, SUP112 and SUP113 of Saccharomyces cerevisiae have been identified that can mutate to give recessive omnipotent nonsense suppressors. Alleles of these loci can also act as allosuppressors; that is, different phenotypes, due apparently to different efficiencies of suppression, can result from different alleles at a given locus. The SUP111, SUP112 and SUP113 loci map to the right arms of chromosomes VIII, VII and XIII, respectively.

Recessive UAA suppressors of the yeast Saccharomyces cerevisiae.

Recessive lysine-independent revertants were isolated from a psi + haploid strain of the yeast Saccharomyces cerevisiae containing one of the leucine-inserting UAA suppressors, SUP29, and various UAA mutations including lys1-1. The majority of the revertants were found to have recessive suppressors in addition to the pre-existing SUP29 mutation. The recessive suppressors were able to suppress only a very limited number of UAA mutations, and none of the UAG mutations thus far examined. The recessive inefficient UAA suppressors were assigned to three complementation groups, sup111, sup112, and sup113. A high incidence of gene conversion was observed for an allele of sup111. An antisuppressor acting on sup111, but not detectably on SUP29, was inadvertently obtained during the course of the study. Interactions between SUP29, sup111 and the antisuppressor asu12 were studied.

Omnipotent Suppressors Effective in psi Strains of SACCHAROMYCES CEREVISIAE: Recessiveness and Dominance.

We have characterized recessive and dominant omnipotent suppressor mutations obtained by conversion of the leu2-1 UAA mutation and the met8-UAG mutation in a psi(+) strain of Saccharomyces cerevisiae. The suppressors that act recessively upon these markers fell into two complementation groups; the sup47 and sup36 suppressors show linkage to the tyr1 locus and the aro1 locus, respectively. Of the suppressors acting dominantly upon both markers, those linked to the tyr1 locus are alleles of the SUP46 ribosomal mutation. The sup47 suppressors differ from the SUP46 suppressors not only in their suppressor activities in heterozygous diploids but also in their map positions relative to the tyr1 locus and their effects on the S11 ribosomal protein. The remaining dominant suppressors are not alleles of sup36 as judged by linkage analysis. The recessive suppressors and the dominant suppressors also differ in their effects on cell growth.

A novel point mutation in the steroid sulfatase gene in X-linked ichthyosis.

We analyzed the steroid sulfatase (STS) gene in nine Japanese patients with X-linked ichthyosis (XLI) by a polymerase chain reaction technique and subsequent DNA sequencing. Eight of nine patients showed complete deletion of the STS gene. In a patient of XLI exhibiting a normal amplifying pattern with predicted sizes of the STS gene, a novel mutation was found resulting in the appearance of a stop codon in exon 7 of the STS gene. This suggests that exon 7 or an area in its downstream region is important for STS activity.

Effect of calmodulin inhibitors on thyroid hormone secretion.

The effect of calmodulin inhibitors, N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W-7) and trifluoperazine, on TSH-induced thyroid hormone secretion from rat thyroid was examined in vivo and in vitro. The ip administration of 5 mg W-7 to the rat inhibited T4 and T3 secretion from rat thyroids at 2, 3, and 4 h after the ip injection of 2 IU TSH, and so did the ip injection of trifluoperazine at 3 and 4 h. However, the ip injection of N-(6-aminohexyl)-1-naphthalene sulfonamide as a control substance did not show any significant inhibition of T4 and T3 release. To identify the site of action of calmodulin, the effect of W-7 on (Bu)2cAMP-induced thyroid hormone secretion was tested in vitro. One hundred micromolar W-7 completely inhibited T4 release from the rat thyroid when it was enhanced by TSH or (Bu)2cAMP, suggesting that the inhibitory effect of W-7 is subsequent to cAMP formation. These results suggest that calmodulin may play a role in thyroid hormone secretion from the thyroid, acting beyond cAMP formation.

Enolase subunits in patients with neuroendocrine tumors.

Concentrations of the alpha-, beta-, and gamma-subunits of enolase in surgically resected tumors and serum obtained from patients with various endocrine tumors were measured by a sensitive enzyme immunoassay system. Tissue concentrations of the gamma-subunit were significantly elevated in patients with neuroendocrine tumors concurrent with high concentrations of the gamma-subunit in their serum, which fell to normal in 90% of those who underwent tumor resection. Immunohistochemical analysis revealed that considerable amounts of the gamma-subunit were contained specifically in these tumors. These results indicate that the gamma-subunit of enolase is a useful marker for diagnosing and monitoring patients with neuroendocrine tumors.

Functional evaluation of cytochrome P450 2D6 with Gly42Arg substitution expressed in Saccharomyces cerevisiae.

A single amino acid-substituted mutant protein, CYP2D6 (G42R) was expressed in Saccharomyces cerevisiae and its enzymatic properties were compared with those of other single (P34S, R296C and S486T) and double amino acid-substituted mutant proteins (P34S/S486T and R296C/S486T) expressed in yeast cells, all of which were known to occur in the CYP2D6 gene as single nucleotide polymorphisms. The protein levels of G42R, P34S and P34S/S486T in microsomal fractions and their oxidation capacities towards debrisoquine as a prototypic substrate and bunitrolol as a chiral substrate were different from those of wild-type CYP2D6, while the R296C, S486T and R296C/S486T behaved similarly to the wild-type in these indices. The CYP contents both in yeast microsomal and in whole cell fractions indicated that some part of G42R protein was localized in the endoplasmic reticulum membrane fraction, whereas most of G42R protein was in some subcellular fractions other than endoplasmic reticulum. In kinetic analysis, the G42R substitution increased apparent Km and decreased Vmax for debrisoquine 4-hydroxylation, while it increased both Km and Vmax for bunitrolol 4-hydroxylation. The P34S substitution did not drastically change Km but decreased Vmax for debrisoquine 4-hydroxylation, whereas Km was increased and Vmax unchanged or decreased for bunitrolol 4-hydroxylation by P34S substitution. These results suggest that the G42R substitution causes a change in the CYP2D6 conformation, which may be different from the change produced by the P34S substitution.

Activation mechanism of human Hageman factor-plasma kallikrein-kinin system by Vibrio vulnificus metalloprotease.

Vivrio vulnificus, an opportunistic human pathogen, secretes a metalloprotease (VVP). The VVP inoculated into a guinea pig is known to generate bradykinin through activation of the Hageman factor-plasma kallikrein-kinin system. VVP was shown to possess the ability to activate the human system through the same mechanism as that clarified in the guinea pig system, namely, VVP converted both human zymogens (Hageman factor and plasma prekallikrein) to active enzymes (activated Hageman factor and plasma kallikrein), and the then generated kallikrein liberated bradykinin from high-molecular-weight kininogen. However, in the presence of plasma alpha 2-macroglobulin (alpha 2M), the VVP action was drastically decreased. This finding suggests that the human system might be activated only at the interstitial-tissue space which contains negligible amounts of alpha 2M or in the bloodstream of the individuals whose plasma alpha 2M level is extremely reduced.

Vacuolar-type H(+)-ATPase in mouse bladder epithelium is responsible for urinary acidification.

The urine in the mouse bladder was found to be acidic, ranging from pH 5.3 to 5.5 in the daytime and pH 6.0 to 6.3 at night. Administration of bafilomycin A1 or concanamycin A, specific inhibitors of vacuolar-type H(+)-ATPase, into bladder lumen caused neutralization of urinary pH at least for 36 h, whereas inhibitors of mitochondrial ATP synthase (F-type H(+)-ATPase) or P-type H(+)-ATPases did not. Bafilomycin A1-sensitive proton secretion from isolated inside-out bladder was also observed. Immuno-electron microscopy with antibodies against vacuolar H(+)-ATPase revealed that vacuolar-type H(+)-ATPase is rich in luminal plasma membrane and endosomes of superficial cells of the bladder epithelium. These results indicate that vacuolar-type H(+)-ATPases present in luminal plasma membrane of the superficial epithelial cells secrete protons so as to acidify the urine in mouse bladder.

Microbial metalloproteases and pathogenesis.

Zinc metalloproteases produced by human pathogenic microorganisms show a wide variety of pathological actions. In local infections, the proteases cause necrotic or hemorrhagic tissue damage through digestion of structural components of the ground substance, and also form edematous lesions through generation of inflammatory mediators, while in systemic infections, the proteases act as a synergistic virulence factor through disordered proteolysis of many plasma proteins. Clostridial neurotoxins, Bacteroides fragilis enterotoxin and Bacillus anthracis lethal factor are also zinc metalloproteases.

Effect of disopyramide on initiation of atrial fibrillation and relation to effective refractory period.

Electrophysiologic studies were performed before and after intravenous administration of disopyramide (2 mg/kg) to 40 patients with either documented or suspected atrial fibrillation (AF). In control studies, sustained AF (greater than 1 minute), nonsustained AF (1 to 60 seconds) and no AF were found in 14, 18 and 8 patients, respectively. After disopyramide, the ability to initiate AF was totally lost in 18 patients (group A), while 22 patients (group B) showed sustained AF (11 patients) or nonsustained AF (11 patients). The effective refractory period of the atrium was 232 +/- 41 ms in the control study and 266 +/- 49 ms after disopyramide. Atrial functional refractory periods before and after disopyramide were 282 +/- 43 and 317 +/- 48 ms, respectively. The differences and ratios of the refractory periods after and before disopyramide were higher in group A than in group B (p less than 0.001). The prolongation of atrial refractoriness after disopyramide was important to suppress the initiation of AF in group A. In some group B patients, on the other hand, the initiation of AF was promoted after disopyramide. Disopyramide may alter the atrial electrophysiologic substrate required for AF initiation.

Alpha-macroglobulin-like plasma inactivator for Vibrio vulnificus metalloprotease.

The metalloprotease produced by Vibrio vulnificus (VVP) is known to be quickly inactivated by plasma proteins which belong to the class of alpha-macroglobulins in vitro at a molar ratio of 1:1. But the in vivo potential of the inactivators has not been studied. Macroalbumin (MA), a member of alpha-macroglobulins in guinea pig plasma, was found to inactivate VVP by means of physical entrapment in vitro. In vivo actions of VVP, permeability-enhancing and hemorrhagic actions, were greatly augmented by simultaneous injection of the antibody against MA, which had no effect on in vitro proteolytic action toward azocasein. The interstitial-tissue space in the normal guinea pig skin contains a negligible amount of MA. However, sufficient MA was present in the extravascular fluid collected after the intradermal injection of VVP. Besides, in the extravascular fluid, VVP formed a complex with MA and no inactivator other than MA was found. These results indicate that plasma MA leaked from the vascular system owing to the permeability-enhancing and hemorrhagic actions of VVP, resulting in inactivation of VVP in situ.

Inhibitory effect of alpha 2-macroglobulin on Vibrio vulnificus protease.

Vibrio vulnificus, an etiologic agent of wound infections and septicemia in humans, elaborates a metalloprotease which is known to be an important virulence factor of the Vibrio. The proteolytic activity of V. vulnificus metalloprotease (VVP) toward casein and elastin was inhibited by alpha 2-macroglobulin (alpha 2 M) at the molar ratio of 1:1, although partial activity was maintained. Permeability-enhancing and hemorrhagic activities were also inhibited, but the peptidase activity toward Z-Gly-Phe-NH2 was not reduced, even by an excess amount of alpha 2 M. VVP formed a complex with alpha 2 M through cleavage of the bait regions of all four alpha 2 M subunits and elicitation of conformational change of the alpha 2 M molecule, which resulted in entrapment of VVP in the alpha 2 M molecule. The peptidase activity of alpha 2 M-VVP complex was inhibited by low-molecular-weight inhibitors such as phosphoramidon, but IgG antibody against VVP failed to neutralize its peptidase activity. Of human plasma proteins, alpha 2 M was the only inhibitor for VVP. These findings indicate that VVP produced during V. vulnificus infection is inactivated by plasma alpha 2 M that leaks from the vascular system.

Structure and iron transport activity of vibrioferrin, a new siderophore of Vibrio parahaemolyticus.

The structure of vibrioferrin, a siderophore from Vibrio parahaemolyticus, was elucidated based on a combination of partial hydrolysis and spectroscopic techniques. HPLC of purified vibrioferrin showed two peaks with an area ratio of approximately 2:1. However, upon reinjection of each of those isolated compounds, the original chromatographic pattern was obtained, indicating an equilibrium between two compounds in aqueous solution. Consistent with this finding, most of the NMR signals of vibrioferrin were duplicated. The structure was determined as 1-(2-[2-(5-carboxy-5-hydroxy-2-oxo-1-pyrrolidinyl)propionamide]ethyl) citrate, which exists in two epimeric forms resulting from cyclization between an amidic nitrogen of the alanine residue and a keto group of the 2-ketoglutaric acid residue. Transport experiments with 55Fe-labeled vibrioferrin demonstrated the function of vibrioferrin as a siderophore in V. parahaemolyticus. Kinetic studies with mid-log phase cells revealed that the iron uptake system was receptor-mediated, with Km and Vmax values of 67 nM and 54 pmol Fe/mg cell protein/min, respectively. Moreover, iron uptake mediated by vibrioferrin was blocked both by uncouplers and by ATPase inhibitors.

Structures of two polyamine-containing catecholate siderophores from Vibrio fluvialis.

From low-iron cultures of Vibrio fluvialis AQ 0012, two new compounds with siderophore activity were purified by XAD-7 adsorption followed by preparative TLC. Norspermidine and 2,3-dihydroxybenzoic acid were identified as constituents common to both compounds by GC-MS analyses of their acid hydrolytic products. In addition, L-threonine was identified in the hydrolysate of one compound, named fluvibactin. Based on high magnetic NMR analyses, the structure of fluvibactin was established as N4-[2-(2,3-dihydroxy-phenyl)-trans-5-methyl-2-oxazoline-4-yl]carboxy-N1, N7- bis-(2,3-dihydroxybenzoyl)-norspermidine, and that of the other compound as N1,N7-bis-(2,3-dihydroxybenzoyl)-norspermidine. The structures were supported by fast atom bombardment mass spectrometry. Both of the purified compounds restored growth inhibition of the producer strain and V. cholerae Non-O1 induced by ethylenediamine di-(o-hydroxyphenylacetic acid), a potent synthetic chelating agent of ferric iron.

An acute exercise-induced translocation of beta-adrenergic receptors in rat myocardium.

The effect of acute exercise (treadmill running) on rat myocardium beta-adrenergic receptors (beta-AR) was studied. beta-AR was identified in purified sarcolemmal membrane fractions and light vesicle fractions. In control hearts, the number of beta-AR was 21.25 +/- 2.25 and 20.89 +/- 2.89 fmol/mg protein (mean +/- SE) in sarcolemmal membranes and light vesicles, respectively. Immediately after a single bout of dynamic exercise, about 35% of beta-AR was transferred from light vesicles to sarcolemmal membranes (p less than 0.05); concomitantly, isoproterenol-stimulated adenylate cyclase activity also significantly increased in sarcolemmal membranes (p less than 0.05). These results suggest that acute exercise provokes the translocation of beta-AR from a presumably intracellular site (light vesicles) to functional membrane fractions (sarcolemmal membranes) in rat myocardium.

DNA polymerase beta in human thyroid of Graves' disease and thyroid tumors.

We have shown that the level of DNA polymerase beta of rat adrenal cortex is regulated by pituitary trophic hormones and may correlate with their endocrine function. Here we measured DNA polymerase beta activity in human thyroid tissues of various benign and malignant thyroid disorders in order to verify the correlation between DNA polymerase beta activity and endocrine function. In Graves' disease (hyperfunction), the level of DNA polymerase beta per cell was three times higher than in normal thyroid, while in undifferentiated thyroid carcinomas this enzyme level was lower than normal. Furthermore, DNA polymerase beta in the crude extracts of cancer cells showed larger molecular forms, ranging from five to 12S, upon sucrose gradient sedimentation. These observations further support the hypothesis that the activity of DNA polymerase beta correlates, in part, with the functional level of the endocrine organ and with cell differentiation.