A metabotropic glutamate receptor agonist DCG-IV suppresses synaptic transmission at mossy fiber pathway of the guinea pig hippocampus

The effects of specific metabotropic glutamate receptor (mGluR) agonists on field excitatory postsynaptic potentials (fEPSPs) at mossy fiber-CA3 synapses were examined in guinea pig hippocampal slice preparations. Application of a novel and potent group II-selective mGluR agonist (2S,1'R,2'R,3'R)-2-(2,3-dicarboxycyclopropyl)glycine (DCG-IV; 0.1 microM) reversibly reduced the fEPSPs. Both the group III-selective agonist DL-2-amino-4-phosphonobutyric acid (AP4; 50 microM) and the broad-spectrum agonist 1S,3R-1-aminocyclopentane-1, 3-dicarboxylic acid (1S,3R-ACPD; 5 microM) also reversibly suppressed the fEPSPs. These results suggest that multiple mGluR subtypes (belonging to groups II and III) are expressed at mossy fiber synapses of the guinea pig hippocampus and activation of the receptors reduces the synaptic excitation, although we cannot exclude the possibility that guinea pig mossy fiber-CA3 synapses express a single class of mGluRs with unique pharmacological profiles.

Randomized controlled trial of acellular diphtheria, pertussis and tetanus vaccines in southern Ghana

A randomized controlled trial of acellular diphtheria/pertussis/tetanus (ADPT) freeze-dried and liquid vaccines in infants was conducted in a peri-urban community (Ashaiman) in southern Ghana. Immunogenicity of the acellular vaccines, persistence of antibodies and adverse reactions were compared with those achieved with a whole-cell diphtheria-pertussis-tetanus (DPT) vaccine. The incidence of pertussis in the vaccine groups and prevalence of pertussis in children under 5 years of age in the study area were also determined. The acellular vaccines produced significantly fewer local and systemic reactions. Local reactions such as swelling and redness were observed in 2% (8/399) to 2.3% (9/385) of the acellular vaccine recipients as against 31% (122/394) in the whole-cell vaccine group. Fever ( > or = 37.5 degrees C) occurred in 7.27% (29/399) to 9.8% (38/385) in the acellular vaccine groups compared with 36.6% (145/394) in the whole-cell vaccine group. Geometric mean titres (GMTs), measured by ELISA, to pertussis toxin (PT) and filamentous haemagglutinin (FHA) were significantly higher in the acellular vaccine groups than in the whole-cell DPT (WCDPT) group. There were no significant differences in the GMTs of tetanus and diphtheria antitoxins between the two groups after each vaccination. Twelve months after primary vaccination, GMTs to PT in the freeze-dried, liquid ADPT groups and the WCDPT group have fallen from 56.23, 62.63 and 44.97 ELISA U/ml to 6.08, 6.18 and 11.30 ELISA U/ml, respectively. GMTs to FHA in all the vaccine groups also dropped during the same period from 49.94, 41.73 and 20.74 ELISA U/ml to 7.26, 7.72 and 5.91 ELISA U/ml, respectively. In this comparative controlled trial, the ADPT vaccines were more immunogenic, with less local and systemic reactions, than the WCDPT vaccine but there was a considerable drop in antibody titres in all the vaccine groups 12 months after primary vaccination. However, the levels of titres of anti-PT and anti-FHA antibodies in all the three vaccines that confer protection are not known. Further studies are necessary to provide this information in order to assess the need for subsequent booster doses after primary immunization with both ADPT and WCDPT vaccines.

Detection by polymerase chain reaction of wild-type measles virus genome in the cerebrospinal fluid of a patient with SSPE who had received measles vaccine

BACKGROUND

Previous studies have reported that approximately 4-5% of patients with subacute sclerosing panencephalitis (SSPE) were given measles vaccination but had no history of natural measles. However, in the case who received measles vaccine, it has been extremely difficult to determine whether the actual cause of SSPE is the inoculated vaccine virus or not.

OBJECTIVES

To detect the measles virus genome in a patient with SSPE and to analyze its nucleotide and deduced amino acid sequence.

STUDY DESIGN

We applied the polymerase chain reaction (PCR) to detect the measles virus genome in specimens from a 12-year-old boy with SSPE who had received measles vaccine 10 years before and had no history of apparent natural measles. The oligonucleotide primers for PCR were prepared based on the nucleotide sequence of the F and NP genes of the measles virus Edmonston strain.

RESULTS

F and NP genes were detected in both the cerebrospinal fluid and peripheral blood lymphocytes. Nucleotide and deduced amino acid sequence analysis of the F gene showed that the patient's virus was different from that of the vaccine strain. Judging from these results, it was likely that the SSPE-associated strain in this case was derived from the wild-type rather than the vaccine strain.

CONCLUSIONS

PCR is a useful method to establish a definitive diagnosis of SSPE and to study the nature of the SSPE-associated virus.

Comparison of diphtheria-tetanus-two component acellular pertussis vaccines in United States and Japanese infants at 2, 4, and 6 months of age

OBJECTIVE

We compared the diphtheria and tetanus toxoids and bicomponent acellular pertussis vaccine (DTaP) responses in Japanese and United States infants.

DESIGN

This was a double-blind, comparative study.

SETTING

Private pediatric practices in Japan and the U.S. participated.

SUBJECTS

One hundred eighty-nine healthy 2-month old infants were tested.

INTERVENTIONS

Infants were immunized at 2, 4, and 6 months of age. The Japanese formulation (DTaP-J) contained 20 micrograms of pertussis toxin (PT) and 20 micrograms of filamentous hemagglutinin (FHA); the U.S. formulation (DTaP-US) contained 23.4 micrograms of each antigen. Parents used a standard form to record average adverse experiences. Serum was obtained before the first immunization, 2 months after the second immunization, and 1 month after the third immunization.

MEASUREMENTS

Differences in DTaP-J and DTaP-US were evaluated in Japanese infants immunized subcutaneously (s.c.). Differences due to ethnicity and to route of administration were compared in U.S. infants immunized with DTaP-US s.c. or intramuscularly (i.m.). An indirect enzyme-linked immunosorbent assay was used to determine immunoglobulin G antibody responses to PT, FHA, and tetanus toxoid. Neutralizing antibody to PT was measured by a Chinese hamster ovary call assay. Diphtheria antitoxin was assayed by serum neutralization on VERO cells.

RESULTS

Statistical differences (P < .05) in adverse events included less fatigue after immunization with DTaP-US compared with DTaP-J. Erythema of more than 2.5 cm was more frequent, but erythema less than 2.5 cm was less frequent in Japanese infants compared with U.S. infants. Fewer Japanese infants were febrile ( > 38 degrees C), tired, or irritable. Subcutaneous immunization resulted in a greater frequency of erythema and induration. The DTaP-US resulted in an equivalent response to PT and a greater response to FHA. More Japanese infants demonstrated at least a fourfold response over preimmunization antibody values to FHA. In U.S. infants, antibody responses to the contained pertussis antigens were equivalent after i.m. and s.c. administration. Compared with Japanese infants receiving DTaP-J s.c., U.S. infants receiving DTaP-US i.m. had equivalent responses to PT and a greater response to FHA.

CONCLUSIONS

United States infants receiving an i.m. injection of a U.S. -produced bicomponent DTaP vaccine produced antibody responses to the contained pertussis antigens at least equal to those of Japanese infants receiving a similar bicomponent DTaP vaccine shown to be effective in older Japanese children.

Mite-specific induction of interleukin-2 receptor on T lymphocytes from children with mite-sensitive asthma: modified immune response with immunotherapy

BACKGROUND

The efficacy of immunotherapy is still controversial. To elucidate the mechanisms of immunotherapy, we studied mite-specific induction of IL-2 receptor (IL-2R) expression on T lymphocytes from children with mite-sensitive asthma.

METHODS

Peripheral blood mononuclear cells were obtained from 28 children with mite-sensitive asthma: 13 had never received house dust immunotherapy (nonimmunotherapy group), 15 had been receiving house dust immunotherapy at the time of the study (immunotherapy group). After a 6-day culture with or without Dermatophagoides farinae (Df) antigen, the expression of IL-2Rp55 (CD25) and p75 on CD4+ or CD8+ T lymphocytes was measured by flow cytometry.

RESULTS

The nonimmunotherapy group showed significant Df-specific CD25 induction on CD4+ T lymphocytes (delta CD4+ CD25+) but little induction on CD8+ T lymphocytes (delta CD8+ CD25+). delta CD4+ CD25+ was correlated with the severity of the disease. In the immunotherapy group delta CD8+ CD25+ was significantly higher than in the nonimmunotherapy group or in normal subjects and correlated with Df-specific IgG4 and cumulative doses of house dust extract, whereas delta CD4+ CD25+ was similar in the nonimmunotherapy and the immunotherapy groups. IL-2Rp75 was not induced either on CD4+ or CD8+ T lymphocytes.

CONCLUSIONS

Our data suggest that house dust immunotherapy may have induced Df-specific CD8+ T lymphocytes in patients with mite-sensitive asthma and that the efficacy of immunotherapy may be attributed to the generation of Df-specific CD8+ T lymphocytes.

Antibody responses in volunteers induced by nasal influenza vaccine combined with Escherichia coli heat-labile enterotoxin B subunit containing a trace amount of the holotoxin

Evaluation of the efficacy of nasal influenza vaccine combined with Escherichia coli heat-labile enterotoxin B subunit (LTB) containing a trace amount of the holotoxin (LT) in inducing antibody responses among volunteers, which was conducted during the winter season of 1993-1994, is reported. A trivalent inactivated vaccine, composed of A/Yamagata/32/89 (H1N1), A/Kitakyusyu/159/93 (H3N2) and B/Bangkok/163/90 influenza virus strains, was used alone or together with the adjuvant, recombinant LTB supplemented with 0.5% recombinant LT (LTB*). The volunteers were divided into two groups: 73 volunteers (mean age 35.0 +/- 12.0 years) inoculated intranasally (i.n.) with LTB*-combined vaccine and 49 volunteers (37.9 +/- 11.3) inoculated i.n. with the vaccine alone. Vaccination was done twice 4 weeks apart. Salivary secretory IgA and serum hemagglutination-inhibiting (HI) antibodies were measured before and 8 weeks after the primary vaccination. For the sake of convenience, more than a 1.4-fold rise in IgA antibody response (units of specific IgA antibody per microgram of total IgA) and a fourfold or greater rise in HI antibody titer after vaccination were regarded as a positive antibody response. Thirty-seven (50.3%) and 36 (49.3%) of the 73 vaccinees, respectively, given the nasal LTB*-combined vaccine showed positive IgA and HI antibody responses to one or more of the three vaccine strains. In comparison, positive antibody responses in the group given vaccine alone were 32.7% for IgA and 30.6% for HI antibody. There was a significant difference between these two groups. These results suggest that the nasal LTB*-combined vaccine could enhance the production of higher levels not only of serum HI antibody but IgA antibodies in the respiratory tract than do the nasal vaccine alone.

Role of adhesion molecules in natural killer cell-induced DNA fragmentation of cytomegalovirus-infected fibroblasts

We investigated the roles of CD11a, CD11b, CD18, and CD54 adhesion molecules in non-adherent peripheral blood mononuclear cells (NPBMC)-induced DNA fragmentation of cytomegalovirus (CMV)-infected cells. DNA fragmentation in the supernatant from CMV-infected cells and NPBMC was assayed, and cytotoxicity against CMV-infected cells was calculated. Treatment of NPBMC with monoclonal antibodies to CD11a, CD11b, CD18, and CD54 significantly reduced cytotoxicity against CMV-infected cells. A combination of anti-CD11a, anti-CD11b, and anti-CD18 antibodies further inhibited cytotoxicity against CMV-infected cells. Cytotoxicity against CMV-infected cells treated with anti-CD54 antibody was also significantly inhibited. Binding of effector cells to target cells was not affected by treatment of NPBMC or CMV-infected cells with antiadhesion molecule antibodies. These results indicate that LFA-1 (CD11a/CD18), Mac-1 (CD11b/CD18), and ICAM-1 (CD54) adhesion molecules are involved in natural killer (NK) cell-induced DNA fragmentation in CMV-infected cells.

Non-radioactive assay of natural killer cell-mediated cytotoxicity against cytomegalovirus-infected fibroblasts by DNA fragmentation ELISA

Cell-mediated cytotoxicity against cytomegalovirus (CMV)-infected fibroblasts (FS-4 cells) was investigated by a non-radioactive assay, and by DNA fragmentation ELISA and LDH release assay and the assays were compared to the standard chromium release assay. Fragmentation of DNA and LDH activity were detected in the supernatant of CMV-infected FS-4 cells cultured with non-adherent peripheral blood mononuclear cells (PBMC). The DNA fragmentation ELISA was most sensitive to cytotoxicity against CMV-infected FS-4 cells and showed excellent correlation with the standard chromium release assay. DNA fragmentation of CMV-infected FS-4 cells by non-adherent PBMC was reduced markedly by treatment with anti-leu 11b plus complement. Thus, the present DNA fragmentation ELISA is non-radioactive, highly sensitive and a useful method for detecting natural killer cell-mediated cytotoxicity against CMV-infected fibroblasts.

Molecular cloning of the defense factor in the albumen gland of the sea hare Aplysia kurodai

Aplysianin-A, an antibacterial glycoprotein in the albumen gland of the sea hare Aplysia kurodai, inhibited the growth of both Gram-positive and Gram-negative bacteria. Aplysianin-A cDNA clones were isolated from an albumen gland cDNA library. Sequence analysis reveals that aplysianin-A is produced as a precursor protein of 556 amino acid residues with a signal peptide of 19 amino acid residues and contains 6 potential N-glycosylation sites. Aplysianin-A mRNA was expressed tissue-specifically in the albumen gland. Homology search reveals that aplysianin-A has a 50% overall amino acid sequence homology to achacin, an antibacterial glycoprotein of the giant African snail Achatina fulica.

Nitric oxide is a mediator of tachykinin NK3 receptor-induced relaxation in rat mesenteric artery

1. The mechanism of vasodilatation induced by tachykinin peptides was studied in isolated mesenteric arteries of rats. 2. Senktide, a selective NK3 agonist, elicited potent endothelium-dependent relaxation of arteries precontracted with phenylephrine (10(-5) M), but an NK1 agonist did not. 3. A non-peptide NK3 antagonist, SR 142801, inhibited senktide-induced relaxation. However, a non-peptide NK1 antagonist, CP-96,345, and a peptide-based NK2 antagonist, L-659,877, had no effect on senktide-induced relaxation. 4. N omega-nitro-L-arginine (L-NOARG), a nitric oxide synthesis inhibitor, markedly attenuated the relaxant response to senktide. 5. These results suggest that the endothelium of rat mesenteric arteries possesses tachykinin NK3 receptors, and that NK3 agonist-induced vasodilatation is mediated by release of nitric oxide (NO) from the endothelium.

Markedly elevated levels of β2-microglobulin in urine with measles viruria in patients with measles

BACKGROUND

Measles is a highly contagious infectious disease in children. However, the pathogenesis has not yet been fully defined since susceptible cells to measles virus (MV) had not been developed. Recently, B95a cells, which are very susceptible to MV, have been reported.

OBJECTIVES

To evaluate measles viruria in patients with measles, isolation of MV from urine was performed using B95a cells.

STUDY DESIGN

Isolation of MV from supernates or sediments of urine in patients with measles was performed using B95a cells. The levels of beta2-microglobulin (MG) in urine and serum were also measured.

RESULTS

MV was isolated from either supernates or sediments of urine. MV was isolated from 10 of 11 samples (91%) within 2 days of the appearance of a rash. MV was isolated from supernates of urine for up to 4 days after the appearance of a rash, and from sediments for up to 5 days. The levels of urinary beta2-MG were elevated within 2 days of the appearance of a rash. The levels of urinary beta2-MG with measles viruria were significantly higher compared to those without measles viruria.

CONCLUSIONS

Measles viruria may occur early in all patients with measles and elevated levels of urinary beta2-MG in patients with measles may be the consequence of tubular injury.

Suppression of presynaptic calcium influx by metabotropic glutamate receptor agonists in neonatal rat hippocampus

Mechanisms of presynaptic inhibition by metabotropic glutamate receptor (mGluR) agonists were investigated in neonatal rat hippocampal CA1 region using the optical recording technique recently developed. Following selective loading of presynaptic terminals with a fluorescent Ca2+ indicator dye rhod-2 AM, changes in Ca2+ signals and the corresponding field excitatory postsynaptic potentials (EPSPs) induced by single electrical stimuli to the Schaffer collateral-commissural (SCC) pathway were recorded simultaneously. Application of a mGluR agonist, 1S,3R-1-aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD; 100 microM) or (+/-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (trans-ACPD; 100 microM), reversibly reduced both the field EPSP and the presynaptic Ca2+ transient, and the quantitative relationship between them was quite similar to that observed during application of Cd2+, a non-selective Ca2+ channel blocker, or in a Ca(2+)-free solution. Application of 4-aminopyridine (4-AP; 1 mM), a blocker of certain subtypes of voltage-dependent K+ channels, significantly inhibited the 1S,3R-ACPD effect. Application of DCG-IV, a novel mGluR2/mGluR3-selective agonist, suppressed field EPSPs only slightly even at a high dose (3 microM). These results suggest that activation of presynaptic mGluR different from mGluR2/mGluR3 suppresses the action potential-triggered Ca2+ influx, probably via 4-AP-sensitive mechanisms, and thereby reduces glutamate release in neonatal rat hippocampal CA1 region.

Immunogenicity and reactogenicity of the component acellular pertussis vaccine produced by a combination of column purified pertussis toxin and filamentous haemagglutinin

This is the report on a prospective, single blind, comparative study of a component acellular pertussis vaccine produced by a combination of detoxified, column purified pertussis toxin (PT) and filamentous hemagglutinin (FHA) combined with diphtheria and tetanus toxoids (DTcaP) and the traditional acellular pertussis vaccine produced with essentially the same method as described by Sato with DT (DTaP) of the same manufacturer. A total of 616 infants and children received DTcaP and a total of 289 received DTaP. In all age groups for both vaccines values of serum antibodies to PT and FHA after two doses of the vaccines were comparable to those of convalescent sera. Incidences of systemic and local reactions were, in general, not greatly different between DTcaP and DTaP recipients. In Japan the use of traditional acellular vaccines replaced whole cell vaccines in 1981. Protective antigens of Bordetella pertussis have now been specified and thus component vaccines have become theoretically possible. This is the first component vaccine which has been developed in Japan. Several other component vaccines are now under investigation in the world.

Formation of a mutagen, glyoxal, from DNA treated with oxygen free radicals

Oxygen free radicals cause extensive chemical changes in DNA, including base and sugar modifications and strand breaks. In the present study we found that a mutagen, glyoxal, is produced by exposure of DNA to an oxygen radical forming system (5 mM FeSO4-EDTA, 37 degrees C, 60 min). It was produced with 17 times higher efficiency than 8-hydroxydeoxyguanosine. Thus it is possible that the formation of glyoxal is one of the major types of damage in DNA exposed to oxygen free radicals.

Formation of 2-hydroxydeoxyadenosine triphosphate, an oxidatively damaged nucleotide, and its incorporation by DNA polymerases. Steady-state kinetics of the incorporation

We found that hydroxylation occurs at the C-2 position of adenine by oxygen radical treatment (Fe2+-EDTA) of dA, dATP, and single- and double-stranded DNA. This oxidatively damaged base, 2-hydroxyadenine, was produced 3-6-fold and 40-fold less than 8-hydroxyguanine when monomers and polynucleotides, respectively, were treated. To determine whether the damaged nucleotide, 2-hydroxydeoxyadenosine triphosphate (2-OH-dATP), is incorporated into a growing DNA, and to reveal the kinds of nucleotides opposite which 2-OH-dATP is incorporated, calf thymus DNA polymerase alpha and the Klenow fragment of Escherichia coli DNA polymerase I were used in vitro DAN synthesis in the presence of 2-OH-dATP. DNA polymerase alpha incorporated the nucleotide opposite T and C in the DNA template. On the other hand, in an experiment using the Klenow fragment, incorporation of 2-OH-dATP was observed only opposite T. Steady-state kinetic studies indicated that incorporation of 2-OH-dATP by DNA polymerase alpha opposite T was favored over that opposite C by a factor of only 4.5. These results indicate that 2-OH-dATP, an oxidatively damaged nucleotide, is a substrate for DNA polymerases and is incorporated incorrectly by the replicative DNA polymerase.

8-Hydroxyadenine (7,8-dihydro-8-oxoadenine) induces misincorporation in in vitro DNA synthesis and mutations in NIH 3T3 cells

An oligodeoxyribonucleotide containing 8-hydroxyadenine (OH8Ade) was chemically synthesized and single- and double-stranded c-Ha-ras gene fragments with OH8Ade at the second position of codon 61 were prepared. The single-stranded ras gene fragment was used as a template for in vitro DNA synthesis with the Klenow fragment of Escherichia coli DNA polymerase I, Taq DNA polymerase, rat DNA polymerase beta and mouse DNA polymerase alpha. The former two enzymes exclusively incorporated dTMP opposite OH8Ade. The DNA polymerases alpha and beta misinserted dGMP, and dAMP and dGMP, respectively. The c-Ha-ras gene was constructed using the double-stranded ras gene fragment containing OH8Ade and was transfected into NIH 3T3 cells. The gene with OH8Ade induced focus formation, indicating that OH8Ade elicited point mutations in cells. When c-Ha-ras genes present in transformed cells were analyzed, an A-->G transition and an A-->C transversion were detected. These results indicate that OH8Ade induced misincorporation in in vitro DNA synthesis and mutations in mammalian cells.

Detection of varicella-zoster virus (VZV) DNA in throat swabs and peripheral blood mononuclear cells of immunocompromised patients with herpes zoster by polymerase chain reaction

BACKGROUND

Varicella-zoster virus (VZV) is rarely isolated from throat swabs and peripheral blood leukocytes from patients with herpes zoster by conventional virus isolation methods. The polymerase chain reaction (PCR) is a highly sensitive method to detect VZV genomes. It has been reported that VZV DNA was detected in the cerebrospinal fluid (Puchhammerstockl et al., 1991) and peripheral blood mononuclear cells (PBMC) of patients with VZV-associated neurological symptoms (Gilden et al., 1992) by PCR.

OBJECTIVES

We used the nested double PCR to detect VZV DNA in patients with herpes zoster.

STUDY DESIGN

Sixteen patients with herpes zoster, ten immunocompromised and six immunocompetent patients, were studied. Throat swabs and PBMC were collected weekly and examined for VZV DNA by the nested double PCR.

RESULTS

VZV DNA was detected in 60% (6/10) of throat swabs and in 60% (6/10) of PBMC of immunocompromised patients, and in 16.7% (1/6) of throat swabs and in 33% (2/6) of PBMC of immunocompetent patients within two weeks after the onset of skin rash. VZV DNA was detected in throat swabs or PBMC of two patients 5 and 7 days after cessation of acyclovir.

CONCLUSION

VZV DNA was detected in throat swabs and PBMC-associated viremia exist in patients with herpes zoster. It is suggested that VZV spread from sensory ganglia to the skin or pharyngeal area along the nerve fiber or hematogenously and local cutaneous replication of VZV can lead to viremia with subsequent hematogenous dissemination in patients with herpes zoster.

High incidence of point mutation in K-ras codon 12 in carcinoma of the fallopian tube

BACKGROUND

Adenocarcinoma of the fallopian tube is a rare tumor with a poor prognosis. Whether these carcinomas possess any genetic changes that contribute to their malignant behavior is unknown and to date few studies regarding the molecular pathogenesis of these tumors have been reported. In adenocarcinoma of the endometrium, mutations in the first exon of K-ras, although relatively infrequent, were observed to be an independent risk factor for poor clinical outcome.

METHODS

Eight patients with adenocarcinoma of the fallopian tube were examined for mutations in the 12th codon of K-ras. DNA was obtained from single sections of paraffin embedded tumor tissue and the first exon of K-ras was amplified by the polymerase chain reaction. Point mutations were assayed using a nonradioactive restriction fragment length polymorphism technique.

RESULTS

The eight patients in this study varied in clinical stage from I-IV and were all treated with surgery and chemotherapy. Six of eight of the patients died and one of the surviving patients had metastases in the vertebrae. K-ras point mutations were detected at codon 12 in seven of the eight tumors (87.5%).

CONCLUSIONS

K-ras mutations occurred with high frequency in this series of eight patients with fallopian tube carcinoma, suggesting that mutations of this protooncogene could play an important role in the molecular pathogenesis of this lesion.

Pertussis immunization with acellular vaccines in Ghanaian children

In the present study, the persistence of antibodies to pertussis antigens was assessed in 51 Ghanaian children immunized with one of two acellular vaccines and one whole cell vaccine in early infancy. The effect of a booster dose 1 year after primary immunization was also examined. Antibody titres to pertussis toxin (PT) and filamentous haemagglutinin (FHA) were measured 1 month and 1 year after primary immunization and 1 month after the booster dose. Although geometric titres (GMTs) to FHA were significantly higher in the two types of acellular vaccinees in the whole cell vaccinees 1 month after primary immunization, GMTs to FHA and PT after 1 year were not significantly different in the three groups. Geometric mean titres to PT and FHA following the booster dose were significantly higher in the acellular vaccinees than in the whole cell vaccinees. Seropositivity rates to PT and FHA in the acellular vaccinees, which were more than 93.3% 1 month after primary immunization, ranged from 50.0 to 77.8% after 1 year. In conclusion, the acellular vaccines did not produce higher antibody levels than the whole cell vaccine 1 year after primary immunization. The booster dose was essential to maintaining sufficient seropositivity to pertussis antigens.

[Four cases of hemolytic uremic syndrome (HUS) associated with serotype O165 verotoxin producing Escherichia coli (VTEC) identified by LPS-solid phase enzyme-linked immunosorbent assay (ELISA)]

Enzyme-linked immunosorbent assay using LPS derived from newly recognized serotype O165 verotoxin producing Escherichia coli (VTEC) could identify 4 cases of hemolytic uremic syndrome (HUS) associated with O165 VTEC. All 4 cases showed a typical clinical course seen in VTEC-associated HUS. We screened 33 cases of HUS whose pathogen was not identified by culture of serodiagnosis. The O165 serotype was not thought to be important not only as a VTEC but also as an enteropathogenic E. coli. However, the prevalence, 4 cases, was as high as of O111 serotype, which is the second major serotype of VTEC in Japan. We have to be careful for this serotype when we look for the pathogen of the patients with hemorrhagic colitis or with HUS.

Impaired expression of interleukin 2 receptor and CD45RO antigen on lymphocytes from children with acute lymphoblastic leukemia in response to cytomegalovirus and varicella-zoster virus

The expression of CD25 and CD45RO in lymphocytes from patients with acute lymphoblastic leukemia in response to cytomegalovirus and varicella-zoster virus antigens was analyzed by flow cytometry. It is suggested that the defects in the immune response to cytomegalovirus and varicella-zoster virus in patients with acute lymphoblastic leukemia on chemotherapy are in the expression of CD25 and in the switching of CD45RA cells to CD45RO cells.

8-Hydroxyguanine (7,8-dihydro-8-oxoguanine) in hot spots of the c-Ha-ras gene: effects of sequence contexts on mutation spectra

We previously reported that 8-hydroxyguanine (7,8-dihydro-8-oxoguanine) at the second position of codon 12 of the c-Ha-ras gene induces many types of mutations in NIH3T3 cells. In this study we incorporated the modified base into the first and second positions of codon 12 in the coding strand and into the first position of codon 61 in the non-coding strand of the gene using a new 8-hydroxyguanine phosphoramidite as a building block during oligonucleotide synthesis. The ras genes with 8-hydroxyguanine were transfected into NIH3T3 cells and the mutations induced were analyzed. 8-Hydroxyguanine residues at the first positions of codons 12 and 61 induced mutations to T at the modified sites almost exclusively. On the other hand, the DNA lesion at the second position of codon 12 induced a G-->A transition in addition to a G-->T transversion, confirming our previous results. Mutations in 5'-flanking sites were observed with 8-hydroxyguanine at the second position of codon 12 or the first position of codon 61. These results indicate that 8-hydroxyguanine in mammalian cells mainly induces a G-->T transversion at the modified site, but that other types of mutations are also elicited.

Misincorporation of dAMP opposite 2-hydroxyadenine, an oxidative form of adenine

Nucleotide incorporation opposite an oxidative form of adenine, 2-hydroxyadenine (2-OH-Ade) was investigated. When a primed template with 2-OH-Ade was treated with an exonuclease-deficient Klenow fragment of Escherichia coli DNA polymerase I (KFexo-), recombinant rat DNA polymerase beta (pol beta) or calf thymus DNA polymerase alpha (pol alpha), incorporation of dTMP and dAMP was observed. In addition, KFexo- inserted dGMP as well. A steady-state kinetic study indicated that the insertion of dAMP and dTMP opposite the DNA lesion occurred with similar frequency with KFexo- and pol beta. Insertion of dTMP opposite 2-OH-Ade was favored to that of dAMP by pol alpha. Chain extension from the A.2-OH-Ade pair is less favored than that from the T.2-OH-Ade pair by all three DNA polymerase. Analysis of full-length products of in vitro DNA synthesis showed that dTMP and dAMP were incorporated by DNA polymerases and that exonuclease-proficient and -deficient Klenow fragments also inserted dGMP opposite 2-OH-Ade. These results suggest that formation of 2-OH-Ade from A in DNA will induce A-->T and A-->C transversions in cells.

Comparison of incorporation and extension of nucleotides in vitro opposite 8-hydroxyguanine (7,8-dihydro-8-oxoguanine) in hot spots of the c-Ha-ras gene

DNA templates with 8-hydroxyguanine (7,8-dihydro-8-oxoguanine, oh8Gua) at a site corresponding to the first or second position of codon 12 of the c-Ha-ras gene were prepared, and the nucleotides inserted opposite the modified base were compared. The Klenow fragment (KF) of Escherichia coli DNA polymerase I inserted C opposite oh8Gua at both positions. Taq DNA polymerase incorporated C and A opposite oh8Gua, and the ratio of C to A was higher at the first position than at the second position. DNA polymerase alpha (pol alpha) inserted A and C at the first position, and A at the second position of codon 12, indicating that the ratio of C to A was higher at the first position. Moreover, we studied the extensions of bases paired with oh8Gua by DNA polymerases with or without 3'-5' exonuclease activity. G and T opposite oh8Gua were removed, and subsequently C was inserted by KF. We found that an oh8Gua:A pair was recognized by the exonuclease activity of the enzyme and that A was partially substituted by C. On the other hand, pol alpha extended only C and A opposite oh8Gua. No difference was observed with oh8Gua at the two positions. These results indicate that the ratio of nucleotides incorporated opposite oh8Gua depends on the sequence context, while there is no particular difference in the extension of base pairs involving oh8Gua by DNA polymerases.