Lyme borreliosis in transgenic mice tolerant to Borrelia burgdorferi OspA or B

The evolution of Lyme borreliosis in transgenic mice tolerant to Borrelia burgdorferi outer surface proteins (Osps) A or B was assessed to investigate the role of immunity to OspA or B in infection and pathogenesis of Lyme disease. Antibodies to OspA or B protect immunocompetent C3H/HeJ or C.B.17 severe combined immunodeficient (scid) mice from challenge with B. burgdorferi. Moreover, arthritis in infected C3H mice resolves with the rise of high titers of B. burgdorferi specific antibodies, including OspA and B, whereas disease persists in scid mice--suggesting that the regression of arthritis may be due to the development of borreliacidal OspA or B antibodies. To evaluate the course of Lyme borreliosis in OspA or B tolerant mice we developed transgenic mice that expressed OspA or B under control of the major histocompatibility complex (MHC) class I promoter. Mice carrying OspA or B transgenes on a C3H/HeJ (C3H, disease-susceptible) or C57BL/6 (B6, disease-resistant) background, immunized with OspA or B, did not mount a humoral or cellular immune response to OspA or B, respectively, but responded normally to other B. burgdorferi antigens. The evolution of Lyme borreliosis, including infection and the development of arthritis and carditis, was similar in transgenic and nontransgenic littermates suggesting that an OspA or B immune response is not singularly involved in either the genesis or regression of Lyme disease in C3H or B6 mice.

Selection of variant Borrelia burgdorferi isolates from mice immunized with outer surface protein A or B

A nonclonal population of Borrelia burgdorferi N40 (passage 3) that survived protective immunity following challenge inoculation of outer surface protein (Osp) A- or B-hyperimmunized mice were characterized for the molecular basis of evasion of immunity. Two of six B. burgdorferi isolates, cultured from OspA-immunized mice, had antigenic diversity in the carboxyl terminus of OspA and did not bind to the protective OspA monoclonal antibody designated IXDII. However, OspA-immunized mice challenged with these variants were fully protected. Moreover, B. burgdorferi isolates with a point mutation in ospB, which results in a truncated OspB that does not bind to protective OspB monoclonal antibody 7E6C, were frequently enriched after infection of OspB-immunized mice. These studies suggest that the incomplete efficacy of an OspA- or OspB-based vaccine may be partly due to immunomediated in vivo selective pressure, resulting in the persistence of some spirochetes that do not bind to protective antibodies.

C-natriuretic peptide but not atrial natriuretic peptide increases cyclic GMP in cerebral arterial smooth muscle cells

A-type natriuretic peptide (ANP) is found primarily in the heart and is released into the circulation. C-type (CNP) is found principally in the brain and has also been detected in the systemic circulation. When injected, both peptides produce vasodilatation most likely by elevation of guanosine 3'5'-cyclic monophosphate (cGMP) in smooth muscle cells via two distinct receptors, NPR-A and NPR-B. In this present study, we determined the effects of these two peptides on intracellular cGMP in smooth muscle cells cultured from pig cerebral and peripheral arteries. In smooth muscle cells cultured from the left anterior descending coronary artery, ANP and CNP increased cGMP with equal potency and efficacy (EC50 for ANP and CNP, 3.6 +/- 0.2 x 10(-8) M and 6.7 +/- 0.8 x 10(-8) M, respectively). In contrast, in smooth muscle cells from cerebral arteries, ANP was without effect while CNP increased cGMP in a concentration dependent manner (EC50: 9.6 +/- 1.7 x 10(-8) M). Stimulation of the soluble guanylyl cyclase with either nitroglycerin or nitroprusside was equivalent in the two cell types. The pattern of response of intracellular cGMP to CNP and ANP in isolated intact arteries from brain and heart was similar to that found in the cultured cells. These results suggest that smooth muscle cells in cerebral arteries express only NPR-B while cells from peripheral arteries can express both NPR-A and NPR-B.

Cloning sequencing and expression of the gene encoding the VP2 protein of the human group B rotavirus, ADRV

Adult diarrheal rotavirus, ADRV, is a noncultivable human group B rotavirus. A complete cDNA copy of ADRV gene segment 2 has been cloned and sequenced. Gene segment 2 contains 2844 bases and encodes one long open reading frame beginning at base 14 and terminating at base 2812. Gene 2 encodes a protein containing 933 amino acids with a calculated molecular weight of 105.6 kDa and a pl of 5.5. The gene 2 polypeptide contains significant homology with the VP2 protein which comprises the core of group A rotavirus strains. The gene 2 protein has been expressed in a rabbit reticulocyte lysate in vitro and is identical in molecular mass with a protein previously demonstrated to be present on iodinated EDTA-treated virions and from in vitro translations of total ADRV mRNA. A recombinant baculovirus containing gene segment 2 has been constructed and used to express the encoded VP2 equivalent protein. The expressed VP2 protein is immunoprecipitable by hyperimmune anti-ADRV serum, porcine group B infection serum, and human convalescent serum but not by hyperimmune serum to group A rotavirus. Our results suggest that ADRV gene segment 2 encodes the VP2 protein equivalent to group A rotavirus strains present in the core of the group B virion.

[The efficacy and side reactions in humans immunized with Danish strain of dried BCG of Shanghai]

A procedure of keeping Danish BCG strain 2 is reported. The strain is cultivated in Bile potato Medium and Suton Potato Medium alternatively with incubation periods of two weeks. Lyophilized vaccine produced by using seeds derived from this strain gives better immunogenicity and lower side reaction to new-born babies and has better thermostability in compare with vaccines derived from strains of Beijing, Brazil, CCCP, France of Hungary.

Sera from patients with chronic Lyme disease protect mice from Lyme borreliosis

Sera from selected patients with Lyme disease in different stages were used to passively immunize mice against Borrelia burgdorferi challenge to determine if human antibodies could protect the animals from infection. Sera from 2 patients with late-stage Lyme disease that contained strong antibody reactivity to proteins in B. burgdorferi lysates, including antibodies to the outer surface proteins (Osps) A and B, partly protected mice from infection after challenge with a small inoculum (10(2)) of B. burgdorferi. Mice immunized with sera from either of these 2 patients developed significantly fewer infections from the borreliae (patient 1 serum, 5%; patient 2 serum, 25%) relative to control mice (patient 1 serum, 90%; patient 2 serum, 74%). In contrast, sera from 2 patients with early or late Lyme disease that lacked antibodies reactive to OspA and OspB did not confer protection. Immunity appeared to be related, at least in part, to the presence of a strong humoral response to the Osps. These results suggest that during prolonged infection, some patients develop an immune response that may be partly protective against reinfection with B. burgdorferi. Therefore, although most patients do not mount a strong humoral response to the Osps during natural infection, vaccination with an Osp may elicit protective immunity.

The effects of 1,25-dihydroxyvitamin D3 on osteoclast formation in fetal mouse metatarsal organ cultures

We have previously described a model system, using 15-day fetal mouse metatarsals cultured in serumless medium, in which osteoclasts and their precursors develop from in situ progenitors in a manner which is similar, both temporally and spatially, to that which occurs in vivo. In this report we evaluate the role of the osteotropic hormone 1,25-dihydroxyvitamin D3 (1,25-D3) on osteoclast formation in this model system by characterizing its effects on proliferation, differentiation, and fusion of cells of the osteoclast lineage. Morphologic evaluation was used to enumerate osteoclast precursors, mono- and multinucleate osteoclasts, and osteoclast nuclei in serial paraffin sections. Dose response data reveal a significant stimulation of osteoclast formation by 1,25-D3 in the range of 0.6 nM to 40 nM, and kinetic analyses suggest that these effects are on proliferation of osteoclast progenitors as well as on differentiation of precursors to form osteoclasts. A single 48 h exposure between day 4 and 6 of culture is necessary and sufficient to induce maximal osteoclast formation, while continuous exposure beyond this "critical period" inhibits multinucleate osteoclast formation. Simultaneous treatment with indomethacin inhibits the effects of 1,25-D3, while treatment with PGE2 stimulates osteoclast formation without significantly increasing precursor numbers, or inhibiting multinucleate osteoclast formation. These results suggest that the effect of 1,25-D3 to induce differentiation of precursors to form mono- and multinucleate osteoclasts is mediated by endogenous prostaglandin synthesis. On the other hand, the inhibition of polykaryon formation observed with continuous 1,25-D3 treatment, does not appear to be a prostaglandin mediated phenomena.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of atrial natriuretic peptide receptors in vascular smooth muscle cells: role of cGMP

We tested the hypothesis that intracellular guanosine 3',5'-cyclic monophosphate (cGMP) regulates atrial natriuretic peptide (ANP) receptors. The effect of chronic exposure to ANP, sodium nitroprusside (SNP), and 8-bromo-cGMP (8-BrcGMP) on ANP receptors and cGMP formation was determined in guinea pig thoracic aorta smooth muscle cells (TASM) and in coronary artery smooth muscle cells (CASM). TASM express both the ANP-activated guanylyl cyclase (B-receptor) and the clearance receptor (C-receptor) and respond to ANP with increased cGMP. CASM exhibit only the ANP C-receptor. In TASM, 24-h treatment with 1 microM atriopeptin (AP) III [rat ANP-(103-126)] caused a sixfold increase in basal cGMP levels, which were unaltered in CASM. In AP III-treated TASM, maximal binding of 125I-labeled AP III (Bmax) was reduced 40% while affinity [dissociation constant (KD)] was unaltered. In CASM, Bmax and KD were not affected. In treated TASM, washed free of AP III, acute dose-response curves of cGMP to AP III were not different from that in untreated cells. In both TASM and CASM, basal cGMP levels were elevated and Bmax was decreased by 6-h treatment with SNP. SNP did not alter the acute response of cGMP to AP III. In both cell types, 8-BrcGMP for 6 h caused reduction in Bmax. These findings support the conclusion that elevated cGMP was necessary for ANP-induced downregulation of receptors. The unaltered responsiveness of cGMP to AP III suggests the B-receptor was not altered and the reduced Bmax was due to decreased C-receptor.

Evasion of protective immunity by Borrelia burgdorferi by truncation of outer surface protein B

We analyzed variability in outer surface protein B (OspB) from Borrelia burgdorferi (Bb), the causative agent of Lyme disease, to determine how Bb escapes immune destruction. We have shown that vaccination with OspB from Bb strain B31 protected mice from infection with Bb B31 but not against Bb N40. The present study demonstrates that Bb N40 spirochetes which evade vaccination immunity to OspB have a truncated form of OspB, due to a TAA stop codon at nucleotide 577. In contrast, Bb N40 spirochetes that express full-length OspB are unable to infect mice immunized with OspB, analogous to our previous studies with Bb B31. Mapping of the OspB antibody response shows that epitopes in the C terminus of OspB are surface-exposed and bind protective monoclonal and polyclonal antibodies. This suggests that the C terminus of OspB is important for eliciting a protective immune response to OspB. Truncation or modification of outer surface proteins that do not bind protective antibody may be a means by which Bb evades host defenses.

Identification and baculovirus expression of the VP4 protein of the human group B rotavirus ADRV

A complete cDNA copy of the fourth RNA segment of the human group B rotavirus adult diarrheal rotavirus (ADRV) has been cloned into lambda phage and excised into plasmid pSK Bluescript. Gene segment 4 contains 2,303 bases and encodes one long open reading frame beginning at base 16 and terminating at base 2263. The encoded protein contains 749 amino acids, with a calculated molecular mass of 84.4 kDa and a pI of 6.1. Gene 4 cDNA was inserted into a recombinant baculovirus via homologous recombination. The gene 4 polypeptide migrates at 84 kDa when expressed either by a recombinant baculovirus or in vitro in a rabbit reticulocyte lysate. The gene 4 protein is immunoprecipitable by hyperimmune serum to ADRV, human ADRV convalescent-phase serum, a porcine group B rotavirus infection serum, and a monoclonal antibody made to ADRV virion. Guinea pig hyperimmune serum to the baculovirus-expressed ADRV VP4 protein recognizes virus and immunoprecipitates an 84-kDa protein from in vitro translations of total ADRV mRNA. In addition, the gene 4-encoded protein shares significant amino acid identity and similarity with the group A rotavirus VP4 protein. This information, together with our previous identification of an 84-kDa protein present on iodinated intact virion but not EDTA-treated ADRV, suggests that gene 4 encodes the VP4 protein equivalent present on the outer capsid of ADRV. The ADRV VP4 protein is also 58% identical to the IDIR rat group B rotavirus gene segment 3 protein. The substantial differences between these two group B VP4 proteins suggests that they are distantly related and likely to define two different group B rotavirus VP4 serotypes. The baculovirus-expressed VP4 protein should be useful for developing serotyping reagents and tests for human and animal group B rotaviruses as well as for addressing the role of VP4 in ADRV neutralization.

[Enhancement of bleomycin or hyperthermia induced tumor cell damage by ADPRT inhibitor]

Enhancement of tumor cell damage by ADPRT inhibitor, 3-aminobenzamide (3AB) was investigated. 3AB could inhibit DNA strand break repair in HeLa S3 cells after treatment with bleomycin. 3AB was able to lower the clonogenic ability of HeLa S3 cells after bleomycin treatment and hyperthermia. 3AB could also prevent potentially lethal damage repair (PLDR) in HeLa S3 cells treated with bleomycin. This work presents some experimental evidence and theoretical background for the possible use of 3AB as a sensitizer in the treatment of cancer.

Rhizobium leguminosarum CFN42 lipopolysaccharide antigenic changes induced by environmental conditions

Four monoclonal antibodies were raised against the lipopolysaccharide of Rhizobium leguminosarum bv. phaseoli CFN42 grown in tryptone and yeast extract. Two of these antibodies reacted relatively weakly with the lipopolysaccharide of bacteroids of this strain isolated from bean nodules. Growth ex planta of strain CFN42 at low pH, high temperature, low phosphate, or low oxygen concentration also eliminated binding of one or both of these antibodies. Lipopolysaccharide mobility on gel electrophoresis and reaction with other monoclonal antibodies and polyclonal antiserum indicated that the antigenic changes detected by these two antibodies did not represent major changes in lipopolysaccharide structure. The antigenic changes at low pH were dependent on growth of the bacteria but were independent of nitrogen and carbon sources and the rich or minimal quality of the medium. The Sym plasmid of this strain was not required for the changes induced ex planta. Analysis of bacterial mutants inferred to have truncated O-polysaccharides indicated that part, but not all, of the lipopolysaccharide O-polysaccharide portion was required for binding of these two antibodies. In addition, this analysis suggested that O-polysaccharide structures more distal to lipid A than the epitopes themselves were required for the modifications at low pH that prevented antibody binding. Two mutants were antigenically abnormal, even though they had abundant lipopolysaccharides of apparently normal size. One of these two mutants was constitutively unreactive toward three of the antibodies but indistinguishable from the wild type in symbiotic behavior. The other, whose bacteroids retained an epitope normally greatly diminished in bacteroids, was somewhat impaired in nodulation frequency and nodule development.

Small-bowel carcinoid presenting in association with a phytobezoar

An unusual case of a recurrent, postoperative, small-bowel obstruction is presented. The obstruction was due to a phytobezoar proximal to the site of a primary carcinoid of the small bowel. The radiologic findings of a mobile, intraluminal filling defect and a more distal, fixed mural mass are reviewed. The cause of the recurrent obstruction was likely a "ball-valve" effect of the phytobezoar at the site of stenosis caused by the carcinoid. This case emphasizes the value of small-bowel imaging in repeated small-bowel obstruction.

Expression of the major inner capsid protein of the group B rotavirus ADRV: primary characterization of genome segment 5

A complete cDNA copy of the fifth RNA segment of the human group B rotavirus, ADRV, has been cloned into plasmid AD512. Gene segment 5 contains 1269 bases and encodes one long open reading frame of 391 amino acids beginning at base 31 and terminating at base 1203. The gene 5 polypeptide, expressed in vitro in a rabbit reticulocyte lysate, comigrates with the 44-kDa major inner capsid protein present on EDTA treated ADRV virions. The gene 5 protein is immunoprecipitable by hyperimmune serum to ADRV, human ADRV convalescent serum and by a group B-specific monoclonal antibody. In addition, this protein shares amino acid identity and similarity with the VP6 proteins from group C and group A rotavirus strains. The ADRV VP6 equivalent protein appears to be more closely related to the group C VP6 than the Group A VP6 polypeptide and a common ancestral rotavirus VP6 precursor protein is suggested. As a result, the fifth RNA segment of ADRV defines the major inner capsid protein, or VP6 equivalent, in the group B rotavirus. Expression of the ADRV VP6 equivalent protein is potentially useful for evaluating the prevalence of serum antibodies to group B rotavirus in human and animal populations as well as for generating antibodies for the direct detection of group B rotavirus antigen.

[Synthesis and animal experiments of ethylnitrosourea]

Ethylnitrosourea (ENU) was synthesized with raw materials such as ethylamine and sodium nitrite. The product was a yellowish powder. Its melting point, solubility and infrared absorption spectrum coincided with those reported in the literature. The result form elementary analysis for the product was almost the same as the theoretical value. The product was applied to rats by various methods. It was found that ENU was a cancerogenic compound, especially to the nervous system. More details about the animal experiments will be published in some other papers.

Morphology and morphogenesis of viruses of hemorrhagic fever with renal syndrome. II. Inclusion bodies--ultrastructural markers of hantavirus-infected cells

Three distinctive types of viral inclusion bodies were identified in hantavirus-infected cells by thin-section electron microscopy. The inclusion bodies, designated granular, granulofilamentous, and filamentous, were intracytoplasmic and closely associated with the rough endoplasmic reticulum and Golgi cisternae. Virus specificity of the inclusions was verified by immune colloidal gold and immunoperoxidase labeling. The inclusion bodies were a common morphological marker for 13 strains of hantaviruses studied, irrespective of their origin.

Antigenic characterization and ELISA detection of adult diarrhea rotaviruses

Recently, severe epidemics of diarrhea among both adults and children in China have been associated with an agent called adult diarrhea rotavirus (ADRV). We have studied ADRV from two areas of China (Jinzhou and Guangxi) and compared them with prototype group A, B, and C rotaviruses. The viral genomes were compared by electrophoresis of the RNA genome segments in polyacrylamide gels, and the antigenic relatedness of these viruses was examined by immune electron microscopic studies using virus preparations of either double- or single-capsid particles. Hyperimmune antisera (guinea pig and rabbit) to one strain of ADRV reacted with high titers with other strains of ADRV and with single-shelled capsids of a porcine group B rotavirus. The antisera to ADRV did not react with either group A or group C rotaviruses. Antisera to either bovine or porcine group B rotaviruses reacted with ADRV but not with the group A or group C viruses. Antisera to group A or group C virus reacted only with their respective homologous virus. These results and those of immunofluorescence studies place the human ADRV rotaviruses from China among the group B rotaviruses. We also report the development of an ELISA to detect ADRV; this ELISA should be useful for defining the epidemiology of these recently described rotaviruses.

Changes in plasma concentrations of thyroxine and triiodothyronine in beef steers fed different levels of propylthiouracil

Three Latin-square trials were conducted to determine the effects of feeding the thyroid depressant propylthiouracil (PTU) on plasma concentrations of thyroxine (T4) and triiodothyronine (T3) in feedlot steers. In trial 1, four steers were fed 0, 1, 2 or 4 mg PTU/kg body weight daily during five 35-d experimental periods. In trial 2, eight steers were fed 0, .5, 1 or 2 mg PTU/kg body weight daily during five 28-d periods. In trial 3, three steers were fed 0, 1 or 4 mg PTU/kg body weight daily during the first 3 d in each of three 28-d periods. In general, feeding PTU caused increases in plasma T4 concentrations that peaked 5 to 7 d after feeding started. Concurrently, T3 concentrations tended to decrease when PTU was fed. The effects of PTU on hormone concentrations were apparent within approximately 1 to 4 h after PTU feeding started. Furthermore, when PTU was not fed, T4 and T3 concentrations appeared to have rhythmic cycles of 90 and 111 min, respectively, and PTU treatment appeared to interrupt this cyclical pattern. After the initial PTU response, the dose response relationship between PTU level and plasma hormone concentration was not linear. Both 4 and 2 mg PTU appeared to depress both T4 and T3 concentrations, suggesting direct inhibition of the thyroid gland and, for the 1-mg PTU treatment, T4 tended to stabilize at concentrations significantly greater than for 0 mg PTU, while T3 concentrations for 1 mg PTU were slightly lower than for 0 mg PTU.(ABSTRACT TRUNCATED AT 250 WORDS)

Triiodothyronine and thyroxine during gestation in dairy cattle selected for high and low milk production

Circulating thyroxine, triiodothyronine, and prolactin were analyzed by radioimmunoassay from two groups of pregnant heifers representing genetic populations that differed by 685 kg milk in their first lactation. At 100 days of gestation, blood samples were taken every 15 min for prolactin assay and every 2 h to determine variations of thyroid hormone serum concentration from 0800 to 2000. Basal serum prolactin concentrations in the two genetic groups were not significantly different. A pattern was consistent for both triiodothyronine and thyroxine; concentrations were lower in the morning and higher during the afternoon. Serum triiodothyronine means were not different in the high-producing (1.84 ng/ml) and low-producing heifers (1.86 ng/ml). Serum thyroxine concentrations were significantly higher in the low-producing heifers (67.84 ng/ml) than in high-producing heifers (59.18 ng/ml). The higher thyroxine concentration in pregnant heifers with lower producing ability suggests a negative relationship of thyroxine to milk yield potential.