Biomedical subjects

B Adler

Publications and source records attributed to B Adler.

At least 145 records · Page 8Linked to original sources

PubMed1989

Experimental immunisation of hamsters with lipopolysaccharide antigens of Leptospira interrogans.

Hamsters were immunised with leptospiral lipopolysaccharide (LPS) or the polysaccharide (PS) fraction of LPS from Leptospira interrogans serovar copenhageni and the antibody responses were measured by agglutination tests. Maximum titres were observed approximately 6 weeks after immunisation and protection against lethal challenge with the homologous strain was afforded by immunisation with as little as 2.5 micrograms of LPS or PS. All animals produced IgM agglutinins but a higher proportion of-animals immunised with PS produced IgG agglutinins than did those immunised with LPS. Immunisation of guinea-pigs with autoclaved PS showed that the preparation retained some but not all of its immunogenic activity.

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMed1989

A dual transcriptional activation system for the 230 kb plasmid genes coding for virulence-associated antigens of Shigella flexneri.

The expression of plasmid-encoded, invasion-related antigens lpa b, c and d of Shigella flexneri was found to be positively regulated at transcriptional level by a 33kD protein produced by the previously defined, virulence-associated Region 1 on the SalI fragment B of the 230 kb invasion plasmid. The gene (designated virB) was identified and its nucleotide sequence determined. No Ipa b or c was produced in the absence of an intact virB gene although lower levels of d were produced. The previously reported regulatory activity of the virF gene some 30 kb distance away was shown to act exclusively through virB. In contrast, the activation of the virG gene necessary for intercellular spread occurred directly by virF without the requirement for virB. This study thus ascribes a critical function to a previously recognized, but functionally undefined, virulence locus on the large invasion plasmid of S. flexneri. The virF gene appears to have a central role in activation of the 230 kb plasmid-encoded virulence genes.

Amino Acid Sequence↗

PubMed1989

Functional organization and nucleotide sequence of virulence Region-2 on the large virulence plasmid in Shigella flexneri 2a.

The 7 kb virulence Region-2 of the large (virulence) plasmid in Shigella flexneri 2a encodes several proteins required for invasion of intestinal epithelial cells. Insertion and deletion mutagenesis, DNA subcloning and SDS-polyacrylamide gel electrophoresis of proteins synthesized in minicells demonstrated five genes in this region. They encode 24, 18, 62 (IpaB), 41 (IpaC) and 37 (IpaD)-kiloDalton (kD) proteins. Complementation of Tn5-induced mutations in Region-2 with the above plasmid constructs indicated that Region-2 consists of two operons and that the three Ipa proteins are essential for the virulence phenotype. The transcriptional organization determined by Northern blotting, S1 nuclease protection and the effect of Tn5 insertions on expression of the Ipa proteins revealed that Region-2 has three promoters that transcribe RNAs of 4.0, 4.5 and 7.5 kb. The 4.0 kb RNA was the transcript for the operon encoding the 24, 18 kD, IpaB and C proteins and the 4.5 kb RNA for the ipaD gene. In addition, the full-length RNA of 7.5 kb which covers Region-2 supplemented full expression of the Ipa proteins. The 7663 nucleotides of Region-2 were determined to confirm the five open reading frames encoding 23,655, 17,755, 62,168, 41,077 and 36,660 Dalton proteins, respectively, and their regulatory sequences.

Amino Acid Sequence↗

PubMed1989

Childhood injuries: a population-based study of emergency room visits in Jerusalem.

A study of childhood injuries of 0-17-year-old Jewish children based on emergency room records of the four major hospitals and the first aid stations was conducted in Jerusalem during 1986. The incidence of visits was 99.7/1000 child-years with 95% confidence intervals (CI) = 98.0-101.5. The rate was 97.2/1000 child-years (CI = 94.4-100.0) among the 0-5-year-old, 114.6/1000 child-years (CI = 111.3-118.0) in the 6-12 age group, and was 93.6/1000 child-years (CI = 90.1-97.1) among 13-17-year-old. The male to female rate ratio was 1.7 for the 0-5-year-olds, 2.1 for the 6-12-year-olds and 2.3 for the 13-17-year-olds. The most frequent causes of injuries were falls, 38.5/1000 child-years (CI = 37.4-39.6), being struck or caught, 21.1/1000 child-years (CI = 20.3-21.9), and road accidents, 5.4/1000 child-years (CI = 5.0-5.8). Only burns among children aged 6 years and over and poisoning among 13-17-year-olds showed a higher incidence among females than among males. The head was the most frequently injured part of the body (45.2/1000 child-years, CI = 44.0-46.4). Head injuries decreased as age increased, while injuries to the extremities and trunk increased with increasing age. Two per cent of the injured children were admitted to hospital.

Accidental Falls↗

PubMed1989

Monoclonal antibodies reacting with serogroup and serovar specific epitopes on different lipopolysaccharide subunits of Leptospira interrogans serovar pomona.

Monoclonal antibodies with two kinds of specificities, produced against Leptospira interrogans serovar pomona, were studied by agglutination and immunoblotting. Antibodies reacted either exclusively with serovar pomona or with all members of the Pomona serogroup, but none of the antibodies reacted with representative serovars of other serogroups. Both antibodies recognized epitopes on purified lipopolysaccharide (LPS) from serovar pomona. In immunoblotting experiments the serogroup specific antibody recognized both the major LPS bands of 21 kDa and 26 kDa whereas the serovar specific antibodies reacted only with the 26 kDa band, thus localizing serovar specificity in the 26 kDa band and serogroup specific epitopes on at least two different LPS subunits.

Animals↗

PubMed1989

Leptospira interrogans serovar hardjo is not a major cause of bovine abortion in Victoria.

The aim of this study was to determine whether evidence could be obtained of foetal infection with Leptospira interrogans serovar hardjo in aborted foetuses collected from dairy farms. Material from 197 abortions occurring over a wide area of Victoria was collected over 3 years. None of 195 foetal kidney cultures or 7 cultures from membranes was positive for leptospiral organisms. Immunogold silver staining for leptospires was performed on sections of kidneys, lungs or heart from 156 foetuses, with negative results. Evidence of transient leptospiral infection in 11 of 123 foetuses was obtained by foetal heart blood serology. Two isolates of L. interrogans serovar hardjo were obtained from the urine of milking cows. These strains were examined by restriction endonuclease analysis and both were shown to be of the genotype Hardjobovis, as have been all Australian isolates studied so far. It appears that foetal infection with serovar hardjo is not associated with any substantial proportion of bovine abortions in Victoria, in contrast to the situation in Northern Ireland. The apparent absence from Victoria of the pathogenic genotype Hardjoprajitno is a possible explanation.

Abortion, Veterinary↗

PubMed1989

Trends in sibling correlations for height and weight: the effect of age changes (0-24 months) and spacing between siblings (0-10 years).

Familial correlations were studied in a sample of 618 sibships from a western neighborhood of Jerusalem, whose height (H) and weight (W) were measured longitudinally at the same age, from birth to 3 years of age. Covariate adjustments were applied to correct for change in mean of H and W with the sex of child and age of mother and for the effect of origin, education, and socioeconomic status of the mother, parity, and calendar year at birth. The highest sibling correlations were observed at birth or 1 month later (r = 0.45-0.46). Pooled sibling correlations were lower 6 months later (r = 0.33; r = 0.26 for H and W, respectively) and tended to increase again 12-18 months after birth. A clear trend of decline in sib-sib correlation for H and W measured 3 and 12 months after birth with increased spacing between siblings was observed. Our data provide evidence for transient environmental factors as possible sources of the observed temporal variation in sibling correlation for height and weight.

Birth Weight↗

PubMed1989

Detection of leptospires in pig kidney using DNA hybridisation.

DNA hybridisation detected leptospiral organisms in homogenised kidneys from experimentally infected pigs, and in homogenates of pig kidneys collected at abattoirs. The technique is easy to perform and had some advantages over cultural and histological methods, in permitting the rapid survey of many kidneys simultaneously. Leptospires added to a homogenate of uninfected kidney could be detected at 10(2) organisms ml-1 by DNA hybridisation, but the technique appeared to be less sensitive than culture.

Abattoirs↗

PubMed1988

Variants of human tissue-type plasminogen activator that lack specific structural domains of the heavy chain.

The heavy chain of tissue plasminogen activator (t-PA) consists of four domains [finger, epidermal-growth-factor (EGF)-like, kringle 1 and kringle 2] that are homologous to similar domains present in other proteins. To assess the contribution of each of the domains to the biological properties of the enzyme, site-directed mutagenesis was used to generate a set of mutants lacking sequences corresponding to the axons encoding the individual structural domains. The mutant proteins were assayed for their ability to hydrolyze artificial and natural substrates in the presence and absence of fibrin, to bind to lysine-Sepharose and to be inhibited by plasminogen activator inhibitor-1. All the deletion mutants exhibit levels of basal enzymatic activity very similar to that of wild-type t-PA assayed in the absence of fibrin. A mutant protein lacking the finger domain has a 2-fold higher affinity for plasminogen than wild-type t-PA, while the mutant that lacks both finger and EGF-like domains is less active at low concentrations of plasminogen. Mutants lacking both kringles neither bind to lysine-Sepharose nor are stimulated by fibrin. However, mutants containing only one kringle (either kringle 1 or kringle 2) behave indistinguishably from one another and from the wild-type protein. We conclude that kringle 1 and kringle 2 are equivalent in their ability to mediate stimulation of catalytic activity by fibrin.

Amino Acid Sequence↗

PubMed1988

Tracking of blood pressure over an eight year period in Jerusalem school children.

Tracking of blood pressure (BP) over an 8-year period between the age of 6 and 14 years and the effect of weight, height, BMI and weight gain has been studied in a population of school children in Jerusalem (n = 533). Pearson's correlation coefficients were 0.65 for weight, 0.61 for height, 0.32 for systolic BP and 0.29 for diastolic BP over an 8-year period. Children maintaining their percentile rank for weight or BMI showed higher correlations than those increasing or decreasing their percentile rank. Girls' menarcheal status did not have a significant effect on the level of BP at 14 years of age. The prevalence of significant and severe BP as defined by the NHLBI Task Force was 1% at 6 years and 0.4% at 14 years. The predictive value of the BP at 6 years for 14 years of age was low even for those with hypertension levels: for SBP 16-33% and for DBP 0-37%. Based on the present study and others, large scale screening of BP is not recommended, rather community based programs aimed at modifying health behaviour in order to prevent development of cardiovascular risk factors and associated morbidity and mortality should be introduced.

Blood Pressure↗

PubMed1988

Antigens recognised by the human immune response to infection with Leptospira interrogans serovar hardjo.

Serum samples from patients infected with Leptospira interrogans serovar hardjo were tested by the microscopic agglutination test (MAT), enzyme immunoassay (EIA) and immunoblotting. There was no apparent correlation between MAT titre and EIA optical density (OD) for individual serum samples, but sequential serum samples produced similar profiles in both tests during the course of an infection. Immunoblotting of hardjo sonicate with patients' sera revealed reactions with a number of bands, in the mol. wt (10(3] range 14.4-95. However, all serum samples reacted with the major 28 x 10(3)-mol. wt sub-unit of hardjo lipopolysaccharide (LPS) and most reacted with a (34.5-35) x 10(3)-mol. wt flagella doublet. Examination of sequential serum samples obtained over a period of about 3 months after infection revealed little change in the antigens detected after the second to third week of infection. Absorption of patients' sera with whole viable leptospires revealed that antibodies to several exposed antigens, including LPS, were produced. Sera which reacted with hardjo flagella also reacted with bands of similar mol. wts in preparations from other serovars.

Agglutination Tests↗

PubMed1988

Identification of leptospiral flagellar antigens by gel electrophoresis and immunoblotting.

Flagella extracted from five serovars, representative of the pathogenic and saprophytic species of the Leptospiraceae, were morphologically similar. Analysis of Leptospira interrogans flagellar preparations by polyacrylamide gel electrophoresis revealed three common major bands in the (30-40) x 10(3)-mol. wt region, and serovar-specific bands in the lower region of the gels. Although some differences were observed, flagella extracted from L. biflexa serovar patoc and Leptonema illini revealed similar electrophoretic profiles to those seen in L. interrogans flagella. Immunoblot analysis showed that while flagellar components in the (20-30) x 10(3)-mol. wt region were recognised only by homologous rabbit antisera, a major protein doublet of (33-34) X 10(3)-mol. wt, depending on the species, was also demonstrated by heterologous antisera. The serovar-specific bands in the (20-30) x 10(3)-mol. wt region were composed of lipopolysaccharide (LPS). These results show that leptospiral flagella are immunogenic and contain antigens which are conserved among the different genera of the family Leptospiraceae.

Antigens, Bacterial↗

PubMed1988

Reaction of monoclonal antibodies with species specific determinants in Leptospira interrogans outer envelope.

A set of 24 monoclonal antibodies (MABs) was produced against an outer envelope preparation from Leptospira interrogans serovar copenhageni. The MABs reacted in enzyme immunoassay with species-specific determinants of an antigen in the leptospiral outer envelope (OE) of pathogenic but not of saprophytic species of Leptospira. The MABs did not agglutinate whole leptospires, nor could they opsonise homologous leptospires for phagocytosis by mouse macrophages or protect new-born guinea-pigs against lethal infection. The MABs reacted by Western blotting with a 35 x 10(3)-mol-wt band in OE separated on SDS-polyacrylamide gels, and also reacted with other bands to a lesser extent. The determinants to which the MABs were directed were localised in the leptospiral OE by immunogold labelling techniques.

Agglutination Tests↗

PubMed1987

Detection of leptospires in biological fluids using DNA hybridisation.

DNA extracted from Leptospira interrogans serovar pomona was labelled with phosphorus-32 by nick translation and used as a genomic probe to detect leptospiral DNA. The sensitivity of detection in a 10-microliter spot on nylon membranes was 160 pg of leptospiral DNA or 1.1 X 10(3) leptospires and assays with nylon membranes were somewhat more sensitive than assays with nitrocellulose membranes. The probe reacted with the pathogenic hardjo and tarassovi leptospiral serovars, but not with other genera of bacteria. To detect leptospires in body fluids, these were treated to free leptospiral DNA and then concentrated on membranes using a Bio-Dot apparatus. Neither serum nor urine interfered with the assay system. The DNA of leptospires added to pig urine was stable for at least 2 h at room temperature and for at least 20 h at -20 degrees C.

Animals↗

PubMed1987

Effect of maternal vaccination on the susceptibility of growing pigs to leptospiral infection.

Serum samples were collected from 30 piglets, derived from 17 litters, whose dams had been vaccinated against leptospirosis. Microscopic agglutination test (MAT) titres against Leptospira interrogans serovar pomona varied greatly from pig to pig; there was less variation among littermates. Titres declined between 4 and 10 weeks of age, with an uncorrected half-life of 15.5 days, consistent with IgG being the main antibody class involved. Twelve pigs, 4 derived from unvaccinated sows and 8 from sows vaccinated against leptospirosis, were challenged intravenously at 8 weeks of age with leptospires of serovar pomona. Colostrum-derived antibody protected 4 out of 8 pigs, and in 1 of the remaining 4 the serological response was reduced. Three of the protected pigs showed reduced serological responses and in the fourth the response was strong, but delayed. All of the pigs derived from unvaccinated sows developed leptospiraemia and leptospiruria and showed strong serological responses. Protection by colostrum-derived antibody bore an inexact relationship to MAT titre, but a titre of 16 appeared to be sufficient for protection.

Agglutination Tests↗

PubMed1987

Genus-specific antigens in Leptospira revealed by immunoblotting.

Immunoblotting of leptospiral sonicates with heterologous rabbit antisera revealed a distinct cross-reactive pattern which differed with respect to the pathogenic and non-pathogenic leptospiral serovars, and that all serovars tested from Leptospira interrogans, L. biflexa and L. illini contained a common 35 kilodalton (Kd) band. A leptospiral genus-specific antigen preparation produced by ethanol fractionation of L. biflexa serovar patoc reacted by enzyme immunoassay (EIA) with all heterologous serovars tested. Further purification using Sephacryl S-300 gel filtration revealed one major cross-reactive peak and several homologous peaks detectable by EIA. Gel electrophoresis of this peak revealed 3 major protein bands of 35, 34 and 29 Kd by Coomassie blue staining. This peak was further fractionated by high pressure liquid chromatography (HPLC), yielding 7 fractions, one of which cross-reacted. Rabbit antisera to this S-300/HPLC fraction reacted with all serovars tested. Immunoblotting revealed 2 distinct groups of cross-reactive antigens, a 33-35 Kd group that was proteinase K sensitive but not reduced by periodate oxidation, and a 14.4-26.5 Kd group whose activity was reduced by periodate but not proteinase K, indicating the presence of both protein and carbohydrate genus antigens. Immunoblotting L. interrogans serovar pomona flagella with S-300/HPLC antiserum suggested that the 35 Kd band found in all serovars tested was a flagellar component.

Animals↗

PubMed1987

Transfection of normal human and Chinese hamster DNA corrects diepoxybutane-induced chromosomal hypersensitivity of Fanconi anemia fibroblasts.

Cultured cells from individuals affected with Fanconi anemia (FA) exhibit spontaneous chromosome breakage and hypersensitivity to the cell killing and clastogenic effects of the difunctional alkylating agent diepoxybutane (DEB). We report here the correction of both of these DEB-hypersensitivity phenotypes of FA cells achieved by cotransfection of normal placental or Chinese hamster lung cell DNA and the plasmid pSV2-neo-SVgpt. Transfectants were selected for clonogenic survival after treatment with DEB at a dose of 5 micrograms/ml. At this dose of DEB, the clonogenicity of normal fibroblasts was reduced to 50% and that of FA fibroblasts was reduced to zero. DEB-resistant (DEBr) colonies selected in this system exhibited a normal response to DEB-induced chromosome breakage and resistance to repeated DEB treatment. The neo and gpt sequences were detected by Southern blot analysis of DNA from one of four DEBr colonies independently derived from transfection of human DNA and one of three DEBr colonies independently derived from transfection of Chinese hamster DNA. In addition, Alu-equivalent hamster sequences were detected in three of seven additional independently derived colonies from transfection of Chinese hamster DNA. The DEBr phenotype of these colonies was stably maintained over several subcultures. Our results demonstrate that DNA sequences that complement the two hallmark cellular phenotypes (cellular and chromosomal hypersensitivity to alkylating agents) of FA are present in human as well as Chinese hamster DNA. The cloning of these genes using transfection strategies can be expected to enable molecular characterization of FA.

Anemia, Aplastic↗

PubMed1987

Opsonic monoclonal antibodies against lipopolysaccharide antigens of Leptospira interrogans serovar hardjo.

Six monoclonal antibodies produced from mice immunised with Leptospira interrogans serovar hardjo were directed against determinants in the leptospiral lipopolysaccharide, as indicated by immunodiffusion and enzyme immunoassay (EIA), and opsonised leptospires for phagocytosis by mouse macrophages. Their specificities were studied by agglutination and EIA. Five antibodies reacted with some, but not all, members of the Sejroe and Hebdomadis serogroups, and one antibody agglutinated exclusively members of the Sejroe group thus indentifying a serogroup-specific epitope. None of the six antibodies reacted with representative serovars of any other serogroup.

Animals↗