[Clinical isolates of group B streptococci from elderly patients]

The importance of Group B streptococcal infection in elderly patients has not been clearly defined. We studied the annual incidence of Group B streptococci (GBS) isolated from sputum and urine of elderly patients who were admitted to Nagoyashi Koseiin Geriatric Hospital. The percentage of GBS isolated has increased since 1988. The type distribution of GBS isolates shows predominantly types Ia, Ib and JM9. The major clinical factors in patients from whom GBS was isolated from sputum were bedridden status, feeding tubes and tracheostomy. We also investigated the antibody to GBS in these elderly patients. The titers of GBS antibody were significantly higher in the group with GBS isolates than in the group without these pathogens. These results suggest that GBS is one of the causative organisms of nosocomial infections in elderly patients.

Sex and strain differences in constitutive expression of fatty acid omega-hydroxylase (CYP4A-related proteins) in mice

The constitutive expression of hepatic fatty acid hydroxylase was examined in both sexes of ddY mice by measuring the activities of lauric acid omega-hydroxylase (LAH). The activity of male mice was significantly higher than that of female mice. Such a sex difference of hepatic LAH activity was not observed in other strains of mice, including BALB/c and C57BL/6. To examine whether decreased total P450 activities caused low LAH activity levels in female ddY mice, ethoxycoumarin O-deethylase activity, which is exhibited by many P450s, was measured in both sexes of mice. This activity had no sex difference. The developmental regulation of hepatic fatty acid hydroxylase was then examined by making consecutive measurements of LAH activity in ddY mice. The activity is the same in immature male and female mice, but is differentiated in the sexually mature state. Furthermore, in male mice, orchiectomy caused a dramatic decrease in hepatic LAH activity and the activity was restored by testosterone treatment to the level of the intact animal. In female mice, ovariectomy and estradiol treatment had no effect on the activity, but testosterone treatment caused an increase in the activity. The above data are consistent with the constitutive expression of CYP4A-related proteins measured by using anti-rat CYP4A1 polyclonal antibody. Anti-CYP4A1 antibody inhibited LAH activity, but not lauric acid (omega-1)-hydroxylase activity. These results suggest that some factors associated with male sex hormone are involved in the regulation of hepatic fatty acid omega-hydroxylase in ddY mice.

Production of nitric oxide (NO) is not essential for protection against acute Toxoplasma gondii infection in IRF-1-/- mice

Production of nitric oxide (NO) by macrophages is important for the killing of intracellular pathogens. IFN-gamma and LPS stimulate NO production by transcriptional up-regulation of inducible nitric oxide synthetase (iNOS). In the present study we used mice with a targeted disruption of the IFN regulatory factor-1 gene (IRF-1-/-) to investigate the importance of NO in the host immune response against Toxoplasma gondii, a major cause of infection in newborns and those with AIDS. IRF-1-/- mice were more susceptible to acute Toxoplasma infection, and treatment with either exogenous IFN-gamma or in vivo neutralization of endogenous IFN-gamma had little effect on their susceptibility to infection. However, administration of exogenous IL-12 was able to prolong survival even when IFN-gamma was depleted. An in vivo depletion study suggested that the mechanism of this protective response is mediated in part by CD4+ T cells. The administration of IL-12 could not overcome the inhibition of lymphoproliferative response in T. gondii-infected mice and treatment with N-monomethyl-L-arginine (L-NMMA), a nitric oxide synthase (iNOS) antagonist in vitro was unable to reverse the immunosuppression. In response to Toxoplasma infection, splenocytes from IRF-1-/- mice exhibited increased production of IL-10 as well as a 30-fold increase in its message expression. These studies indicate that NO may not be essential for host immunity to the parasite, and moreover that IL-12 appears to induce an IFN-gamma-independent mechanism of protection against this opportunistic pathogen.

Production of nitric oxide (NO) is not essential for protection against acute Toxoplasma gondii infection in IRF-1-/- mice

Production of nitric oxide (NO) by macrophages is important for the killing of intracellular pathogens. IFN-gamma and LPS stimulate NO production by transcriptional up-regulation of inducible nitric oxide synthetase (iNOS). In the present study we used mice with a targeted disruption of the IFN regulatory factor-1 gene (IRF-1-/-) to investigate the importance of NO in the host immune response against Toxoplasma gondii, a major cause of infection in newborns and those with AIDS. IRF-1-/- mice were more susceptible to acute Toxoplasma infection, and treatment with either exogenous IFN-gamma or in vivo neutralization of endogenous IFN-gamma had little effect on their susceptibility to infection. However, administration of exogenous IL-12 was able to prolong survival even when IFN-gamma was depleted. An in vivo depletion study suggested that the mechanism of this protective response is mediated in part by CD4+ T cells. The administration of IL-12 could not overcome the inhibition of lymphoproliferative response in T. gondii-infected mice and treatment with N-monomethyl-L-arginine (L-NMMA), a nitric oxide synthase (iNOS) antagonist in vitro was unable to reverse the immunosuppression. In response to Toxoplasma infection, splenocytes from IRF-1-/- mice exhibited increased production of IL-10 as well as a 30-fold increase in its message expression. These studies indicate that NO may not be essential for host immunity to the parasite, and moreover that IL-12 appears to induce an IFN-gamma-independent mechanism of protection against this opportunistic pathogen.

Humanization of an anti-human IL-6 mouse monoclonal antibody glycosylated in its heavy chain variable region

Interleukin-6 (IL-6) inhibitors are good potential therapeutic agents in human patients, and anti-IL-6 antibodies are among the best candidates. Here, we have successfully humanized mouse monoclonal antibody SK2, which specifically binds to IL-6 and strongly inhibits IL-6 functions. Since this antibody possesses N-linked carbohydrates on Asn-30 of VH region, which seems to be very close to an antigen-binding site, influence of these carbohydrates on antigen-binding was investigated. A biosensor study showed that the mouse SK2 Fab and its deglycosylated fragments had almost equal Kd (Kon/Koff), 26.8 nM (1.05 x 10(6)/2.81 x 10(-2)) and 24.7 nM (1.28 x 10(6)/3.15 x 10(-2)), respectively. Furthermore, a mutant chimeric SK2 antibody, in which the N-glycosylation site was removed from the VH region, showed a Kd of 11 nM, almost similar to that of the original chimeric SK2 antibody, determined by Scatchard analysis with 125I-IL-6. These data indicate the carbohydrates of mouse SK2 VH region do not significantly influence antigen-binding activity. In the next step, two versions of each humanized SK2 VL and VH regions were carefully designed based on the amino acid sequences of human REI and DAW, respectively. Only one alteration, Tyr to Phe, was made at position 71 in the two light chains, according to the canonical residue for LI. A N-glycosylation site was introduced on the two heavy chains, by changing Ser to Asn at position 30. All four combinations of humanized light and heavy chains could bind to IL-6 as well as the chimeric SK2 antibody. The light chain first version, however, could not efficiently inhibit IL-6 binding to its receptor, indicating the importance of the LI loop conformation for the inhibitory activity of SK2 antibody. In contrast, both versions of the heavy chains were comparable, in yielding good humanized SK2 antibodies, suggesting that the glycosylation of the SK2 VH region has no influence in recreating a functional antigen-binding site in this humanization.

Effects of gonadectomy and sex hormones on the induction of hepatic CYP4A by clofibrate in rats

The effects of sex hormones on the induction of hepatic CYP4A by clofibrate were examined in intact and gonadectomized rats of both sexes by measuring the activity of lauric acid omega-hydroxylation (LAH). Although the specific activity of LAH is the same in both sexes, only in male rats, was the activity significantly increased by administration of clofibrate. In female rats, ovariectomy or testosterone treatment resulted in an enhanced response to clofibrate, similar to that observed in male rats. In ovariectomized female rats, the effect of clofibrate was decreased by estradiol. In orchiectomized male rats, testosterone had no effect on the induction of LAH by clofibrate and estradiol suppressed induction. Changes in LAH activities co-related well with those in CYP4A proteins and CYP4A1 mRNA. These results suggest that some factors associated with female sex hormones were involved in the suppressive regulation of CYP4A induced by clofibrate.

IL-7 stimulates protective immunity in mice against the intracellular pathogen, Toxoplasma gondii

Cytokines, in particular IFN-gamma and IL-12, are important in host protection against infection with Toxoplasma gondii. This parasite is a major cause of congenital infection and morbidity in immunosuppressed persons, especially those with AIDS. IL-7, a monomeric protein produced by bone marrow stromal cells and fetal thymus, is able to induce the proliferation of pro-B cells and CD4+ and CD8+ T cells, and to enhance cytotoxicity of CTL and NK cells. Inbred mice were infected with a lethal dose of T. gondii and given IL-7 twice daily. Mice treated with IL-7 beginning at the time of infection survived, whereas mice either treated after infection or not treated died. Phenotypic analysis of splenocytes identified an expansion of NK (asialo GM1+) cells and CD8+ T cell populations. In vivo depletion of NK (asialo GM1+) and CD8+ T cells showed that cells expressing these phenotypes were important for maintaining protection against the parasite. IFN-gamma depletion resulted in complete reversal of the protective effect of IL-7 administration. In vivo depletion of endogenous IL-7 enhanced susceptibility to infection. Cytokine analysis by semiquantitative reverse-transcriptase PCR showed that IL-7 enhances the IFN-gamma response and furthermore reverses the parasite-mediated down-regulatory response on IL-2. These observations indicate that exogenous administration of human rIL-7 is able to protect mice against acute parasite challenge by stimulating IFN-gamma production and augmenting the CD8+ T cell-mediated CTL response.

IL-7 stimulates protective immunity in mice against the intracellular pathogen, Toxoplasma gondii

Cytokines, in particular IFN-gamma and IL-12, are important in host protection against infection with Toxoplasma gondii. This parasite is a major cause of congenital infection and morbidity in immunosuppressed persons, especially those with AIDS. IL-7, a monomeric protein produced by bone marrow stromal cells and fetal thymus, is able to induce the proliferation of pro-B cells and CD4+ and CD8+ T cells, and to enhance cytotoxicity of CTL and NK cells. Inbred mice were infected with a lethal dose of T. gondii and given IL-7 twice daily. Mice treated with IL-7 beginning at the time of infection survived, whereas mice either treated after infection or not treated died. Phenotypic analysis of splenocytes identified an expansion of NK (asialo GM1+) cells and CD8+ T cell populations. In vivo depletion of NK (asialo GM1+) and CD8+ T cells showed that cells expressing these phenotypes were important for maintaining protection against the parasite. IFN-gamma depletion resulted in complete reversal of the protective effect of IL-7 administration. In vivo depletion of endogenous IL-7 enhanced susceptibility to infection. Cytokine analysis by semiquantitative reverse-transcriptase PCR showed that IL-7 enhances the IFN-gamma response and furthermore reverses the parasite-mediated down-regulatory response on IL-2. These observations indicate that exogenous administration of human rIL-7 is able to protect mice against acute parasite challenge by stimulating IFN-gamma production and augmenting the CD8+ T cell-mediated CTL response.

CAG repeat expansion of Machado-Joseph disease in the Japanese: analysis of the repeat instability for parental transmission, and correlation with disease phenotype

Machado-Joseph disease (MJD) is caused by abnormal expansion of an unstable CAG repeat in a novel gene locating on chromosome 14q32.1. We analysed this CAG repeat polymorphism with 66 Japanese MJD patients. All the patients were selectively associated with abnormal expansion of the CAG repeat. Repeat length of the mutant allele did not overlap that of normal allele and closely correlated with not only age at onset but also with clinical phenotypes. CAG repeat size is apparently related to a wide variety of phenotypic presentations in MJD.

Splicing mutations in the COL4A5 gene in Alport's syndrome: different mRNA expression between leukocytes and fibroblasts

The COL4A5 gene from 40 patients with Alport's syndrome was examined using single-strand conformation substitution at the acceptor site (-2) of intron 50 and a G-to-C substitution at the donor site (+1) of intron 47, respectively. The transcript in peripheral leukocytes from the former had a 10-nucleotide deletion. This shortened transcript was derived from abnormal splicing in a cryptic acceptor site within exon 51. This could be translated into a protein with an alteration of three amino acids followed by premature termination, which eliminated 23 amino acids from the carboxyl end. Gene tracking revealed that the mother and a brother carried the mutant allele. In the latter, the transcript in leukocytes was normal, but that in cultured skin fibroblasts showed skipping of exon 47, the result being that 71 amino acids were absent. Glomerular basement membrane from the patient did not react with the anti-alpha 5(IV) antibody. His maternal grandmother, mother, and a sister, all with abnormal urinalysis, carried the mutant allele. Thus, the appearance of exons of the COL4A5 gene in leukocytes may differ from that in fibroblasts. If kidney mRNA is not available, mRNAs from cultured skin fibroblasts, in addition to leukocytes, can be used for gene analysis in subjects with Alport's syndrome.

Diagnosis of premature rupture of membranes with an improved alpha-fetoprotein monoclonal antibody kit

We developed a new kit for detecting alpha-fetoprotein (AFP) in leaked amniotic fluid (Eur J Obstet Gynecol Reprod Biol 1995;58:67-72). Later, we developed an improved AFP kit utilizing the same AFP monoclonal antibody. We compared this improved AFP test with the nitrazine test for 137 patients. The nitrazine test correctly diagnosed 62.1% of the cases, but the improved AFP kit diagnosed 98.0% for < 37 weeks of gestation (P < 0.001). The nitrazine test showed a specificity of 58.3%, whereas the AFP kit showed a 100% rate for detecting > or = 37 weeks of gestation (P < 0.01). The reaction time with the AFP kit is 90 s. This study has confirmed a high clinical efficacy of the improved AFP test kit as a method of diagnosis of premature rupture of fetal membranes.

[Anesthesia with transesophageal echocardiography for removal of pheochromocytoma]

A 45-year-old female was scheduled for left adrenalectomy because of a pheochromocytoma. Preoperative general condition was well controlled with alpha- and beta-blockers. Anesthesia was induced with thiamylal and vecuronium, and maintained with isoflurane (0.5-3%) and nitrous oxide in oxygen. Blood pressure was controlled with nicardipine and alpha-blocker during the manipulation of the tumor. After removal of the tumor, dopamine and norepinephrine were used. We used transesophageal echocardiography (TEE) to determine the fluid administration rate and doses of catecholamine. We could observe the wall motion and the mass of the heart, and see changes of the left ventricular enddiastolic volume, the cardiac output and the stroke volume. TEE monitoring seems to be very useful during the resection of pheochromocytoma.

Diagnosis of premature rupture of membranes with an improved alpha-fetoprotein monoclonal antibody kit

We developed a new kit for detecting alpha-fetoprotein (AFP) in leaked amniotic fluid (Eur J Obstet Gynecol Reprod Biol 1995;58:67-72). Later, we developed an improved AFP kit utilizing the same AFP monoclonal antibody. We compared this improved AFP test with the nitrazine test for 137 patients. The nitrazine test correctly diagnosed 62.1% of the cases, but the improved AFP kit diagnosed 98.0% for < 37 weeks of gestation (P < 0.001). The nitrazine test showed a specificity of 58.3%, whereas the AFP kit showed a 100% rate for detecting > or = 37 weeks of gestation (P < 0.01). The reaction time with the AFP kit is 90 s. This study has confirmed a high clinical efficacy of the improved AFP test kit as a method of diagnosis of premature rupture of fetal membranes.

[Clinical study on cerebrovascular diseases after renal transplantation]

Between October 1975 and December 1994, 131 renal transplants were performed on our hospital. Eight of these patients had 9 cerebrovascular diseases, which were 2 cerebral hemorrhages, 5 cerebral infarctions, 2 subarachnoid hemorrhages. Five of the 8 patients whose graft functions were bad died. We studied the relationship of the incidence of these complications to some factors as follows; 1) blood pressure, 2) hypercholestemia, 3) duration of hemodialysis, and 4) graft function. The cerebrovascular diseases after renal transplantation were related to the hypertension after renal transplantation and no correlation with the other factors could be found. Therefore, we think that the control of the hypertension after renal transplantation is the most important for the cerebrovascular diseases and the patient's prognosis.

Attenuation of adrenomedullin-induced renal vasodilatation by NG-nitro L-arginine but not glibenclamide

1. The present study was conducted in order to elucidate the in vivo contribution of nitric oxide (NO) and the glibenclamide-sensitive potassium channel in the renal action of adrenomedullin in anaesthetized dogs. 2. Intrarenal arterial infusion of adrenomedullin (20 ng kg-1 min-1) elicited a pronounced increase in renal blood flow with no changes in systemic blood pressure. The renal vasodilator action of adrenomedullin was markedly attenuated by pretreatment with NG-nitro L-arginine (L-NOARG), but this was reversed by continuous infusion of L-arginine. 3. Pretreatment with glibenclamide almost completely blocked the renal vasodilatation induced by lemakalim, but had no effect on the renal vasodilator and diuretic action of adrenomedullin. 4. Intrarenal arterial infusion of adrenomedullin induced diuresis and natriuresis. Diuretic and natriuretic action of adrenomedullin was also attenuated by L-NOARG. L-Arginine partly reversed the effect of L-NOARG and adrenomedullin-induced diuresis and natriuresis. 5. These data indicate that the in vivo renal vasodilator action of adrenomedullin is mediated by the release of NO. The glibenclamide-sensitive potassium channel is not involved in the renal action of adrenomedullin, at least, not in anaesthetized dogs. Since the inhibition of L-NOARG of adrenomedullin-induced diuresis occurred concomitantly with the attenuation of the renal vasodilator action of adrenomedullin, direct involvement of NO in adrenomedullin-induced diuresis remains to be established.

Oxytocin-producing and vasopressin-producing eosinophils in the mouse spleen: immunohistochemical, immuno-electron-microscopic and in situ hybridization studies

Oxytocin-like and vasopressin-like immunoreactive cells, and the cells expressing mRNAs for these peptides in the spleen of the C57BL/6 mouse were studied by immunohistochemistry, immuno-electron microscopy and in situ hybridization. Immunoreactive cells were distributed mainly in the splenic cord and marginal zone, whereas there were few in the lymphocyte-packed periarteriolar-lymphoid sheath, lymphoid follicle and germinal center. More numerous vasopressin-positive cells were seen in the splenic cord. The colocalization of oxytocin-like and vasopressin-like immunoreactivity in the same cells was identified by the investigation of mirror sections. By the pre-embedding immuno-electron-microscopic method using antisera against oxytocin and vasopressin, immunopositive reaction products were localized in the matrix around the specific granules, small clear vesicles and mitochondrial membrane of the eosinophils. No immunoreactivity to these peptides was found within the specific granules of the eosinophils. In situ hybridization with synthetic oligonucleotide probes labeled with 32P revealed the presence of mRNAs for oxytocin and vasopressin in the cells of the spleen, the distribution of the mRNAs for these peptides being the same as that of immunopositive cells. These observations suggest that eosinophils synthesize both oxytocin and vasopressin and store them in the matrix. Possible differences in the mechanism of synthesis and storage of these peptides between peripheral eosinophils and hypothalamic neurons are discussed.

Expression of a cell adhesion molecule, neuropilin, in the developing chick nervous system

Neuropilin (previously known as the A5 protein) is a membrane protein identified in Xenopus and is presumed to be involved in the target recognition of the optic nerve fibers. We have isolated cDNAs encoding the chick homologue of neuropilin, using the Xenopus neuropilin cDNA as a hybridization probe. The predicted amino acid sequence of chick neuropilin is 75% identical to that of the Xenopus homologue. A cell aggregation assay showed that fibroblasts transfected with the chick neuropilin cDNA acquired cell adhesiveness. This adhesion is mediated by a heterophilic interaction between neuropilin and protease-sensitive molecules on fibroblasts. The expression of chick neuropilin is restricted to certain neuronal circuits and is dynamically regulated during development, as is the Xenopus homologue. However, their expression patterns differed significantly in the visual systems between the two species: In the chick optic tectum, the localization of neuropilin is confined to layers d and e of SGFS, two of the six layers receiving the retinal input; the chick optic nerve fibers do not express neuropilin; in the chick retina, amacrine cells transiently express neuropilin. Cultured neurons of the dorsal root ganglia express chick neuropilin on their neurites including growth cones. These results suggests that neuropilin functions as a cell adhesion molecule during the formation of certain neuronal circuits in vivo.