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A Arends

Publications and source records attributed to A Arends.

At least 19 recordsLinked to original sources
PubMed2003

Lactobacillus GG prevents recurrence of colitis in HLA-B27 transgenic rats after antibiotic treatment.

BACKGROUND AND AIMS: Bacteroides vulgatus induces colitis in gnotobiotic HLA-B27 transgenic (TG) rats while broad spectrum antibiotics prevent and treat colitis in specific pathogen free (SPF) TG rats although disease recurs after treatment ends. Lactobacilli treat human pouchitis and experimental colitis. We investigated if Lactobacillus rhamnosus GG (L GG) can prevent colitis in TG rats monoassociated with B vulgatus and if L GG or Lactobacillus plantarum 299v (LP 299v) can treat established colitis in SPF TG rats and prevent recurrent disease after antibiotics were stopped. METHODS: Germfree B27 TG rats were monoassociated with B vulgatus for four weeks following two weeks of colonisation with L GG or no bacteria. SPF B27 TG rats received oral vancomycin and imipenem for two weeks, or water alone, followed by four weeks of treatment with oral L GG, LP 299v, or water only. Disease activity was quantified by blinded gross and histological scores, caecal myeloperoxidase (MPO) activity, and levels of interleukin (IL)-1 beta, tumour necrosis factor (TNF), transforming growth factor beta, and IL-10. RESULTS: L GG did not prevent colitis in B vulgatus co-associated TG rats or treat established disease in SPF rats. However, L GG but not LP 299v prevented colitis relapse in antibiotic treated rats with reduced gross and histological scores, caecal MPO, IL-1 beta, and TNF whereas caecal IL-10 was increased. CONCLUSIONS: L GG does not prevent colitis in gnotobiotic TG rats or treat established disease in SPF rats, but is superior to LP 299v in the prevention of recurrent colitis. These studies suggest that antibiotics and probiotic agents provide synergistic therapeutic effects, perhaps mediated by altered immunomodulation with selective activity of different lactobacillus species.

Animals↗
PubMed2001

The comparative energetics of 'caviomorph' rodents.

The energetics of 11 species of New World hystricognath ('caviomorph') rodents are presented and compared with data from the literature on 19 additional species. Log(10) body mass alone accounts for 94% of the variation in the log(10) basal rate of metabolism in caviomorphs. The residual variation in basal rate is correlated with the stratum on which species live: arboreal species have low basal rates; terrestrial and fossorial species have intermediate basal rates; and aquatic species have high basal rates. When stratum is not included in the analysis, folivores, especially those that are arboreal, have lower basal rates than species with other food habits when combined with log(10) body mass. Small island endemics, all of which are folivores, have basal rates that are 61% of continental species. Log(10) basal rate correlates with family affiliation when combined with log(10) mass, but only if no other factor is included. Therefore, caviomorphs with low basal rates are arboreal, folivorous, live on small islands and belong to the Capromyidae, whereas other character combinations are associated with higher basal rates. These observations demonstrate that the basal rates of caviomorphs reflect many factor interactions. No differences in basal rate were found to reflect climate. Log(10) mass, the only factor to correlate with conductance, accounts for 82% of the variation in log(10) minimal thermal conductance. Mean interspecific body temperature was 36.9 degrees C; it was lowest in aquatic and fossorial species.

Animals↗
PubMed2000

Determination of beta-globin gene cluster haplotypes and prevalence of alpha-thalassemia in sickle cell anemia patients in Venezuela.

Sickle cell anemia and alpha-thalassemia have a heterogeneous distribution in Venezuela with a high frequency in the coastal area (sea level) and few cases in the mountains. Most of our population is an ethnic admixture of Europeans (Spaniards colonists), Africans (slaves), and Amerindians. The purpose of our study was to determine the origin of the beta(s) globin haplotype, age and survival dependency, and the admixture among the different African groups in our population. The alpha(3.7) globin gene deletion status was also studied and found in a very high frequency. DNA from peripheral blood of 191 non-related patients (81 with HbS homozygous and 15 patients compound heterozygous for HbS, HbC, HbD with beta-thalassemia, and 95 with sickle cell trait) were studied. The beta(s) chromosome was linked 51% to the Benin Haplotype, 29.5% with the CAR, 12.5% to the Senegal, and 2.5% to the Cameroon. We did not find any significant difference between the haplotype distribution among adults and children and among sickle cell patients and traits. Only 8.6% of the patients have homozygosity for the Benin haplotype. These results show a very high frequency of admixture in our African origin population.

Age Distribution↗
PubMed2000

Helicobacter hepaticus does not induce or potentiate colitis in interleukin-10-deficient mice.

Helicobacter hepaticus has been reported to induce colitis, hepatitis, and hepatocellular carcinoma in several different murine models. The aim of this study was to determine if H. hepaticus will cause colitis in monoassociated mice lacking the interleukin-10 gene (IL-10(-/-) mice) and potentiate colitis in specific-pathogen-free (SPF) IL-10(-/-) mice. Germfree IL-10(-/-) mice on either a mixed (C57BL/6 x 129/Ola) or inbred (129/SvEv) genetic background were monoassociated with H. hepaticus ATCC 51448 by oral feeding and rectal enemas. In a second experiment, germfree IL-10(-/-) mice were colonized with stool from SPF mice that harbored or did not harbor endogenous H. hepaticus. After 7 to 9 weeks of colonization, weight loss and mortality were assessed, the colon was isolated for histology and IL-12 secretion, and mesenteric lymph node cells were assessed for T-cell activation markers. It was found that IL-10(-/-) mice monoassociated with H. hepaticus for up to 16 weeks showed almost no histologic colitis or increased IL-12 production. SPF IL-10-knockout mice had no significant difference in weight loss, mortality rate, histologic scores, colonic IL-12 secretion, or T-cell activation with or without H. hepaticus. We conclude that H. hepaticus does not induce or potentiate disease in our IL-10(-/-) mice and therefore is not required to induce colitis in genetically susceptible hosts.

Animals↗
PubMed1999

[Detection of beta thalassemia by the technique of refractory amplification of mutation systems (ARMS-PCR)].

beta Thalassemia (Thal) mutations were studied in DNA from 80/159 patients with hemolytic anemia and high levels of Hb A2 by the amplification refractory mutation system technique (ARMS-PCR). This method detects point mutations and insertions or deletions of just a few nucleotides in the beta globin gene by the polymerase chain reaction of allele-specific priming. In 43/80 patients with different clinical presentations of beta Thalassemia and 37/80 compound heterozygous for hemoglobinopathies and beta Thalassemia the most frequent mutation found was the -29 (of African origin), followed by the CD39 (of Mediterranean origin) and in a lower frequency also was found the -88, the IVSI-6 and the IVSI-110. We conclude that this technique is an useful approach in determining the beta thalassemia mutations in population surveys, because it allows to make a differential diagnosis between beta Thalassemia minor and individuals with high levels of Hb A2. It helps to clarify the diagnosis of patients with structural hemoglobinopathies that also presents high levels of Hb A2.

Base Sequence↗
PubMed1988

Comparison of antibiotic resistant and sensitive strains of Haemophilus influenzae type b in The Netherlands by outer-membrane protein subtyping.

The percentage of beta-lactamase producing Haemophilus influenzae strains from patients with meningitis in The Netherlands increased from 0% in 1975/1976 to 4.6% in 1985/1986 (n = 1559). Twenty-three isolates resistant to ampicillin, penicillin, chloramphenicol, rifampicin and/or tetracycline were subtyped to determine if one resistant strain was spreading. (Sub)typing was performed by capsular typing, analysis of the major outer membrane protein patterns on sodium dodecylsulfate gels (SDS-PAGE subtypes), lipopolysaccharide serotyping and biotyping. The (sub)types of the resistant strains were similar to those of sensitive strains, thus indicating that antibiotic resistant strains develop at random.

Anti-Bacterial Agents↗
PubMed1988

Cross-reactions between Neisseria meningitidis group H and Escherichia coli K2 and K62 polysaccharides.

Neisseria meningitidis group H polysaccharide was found to cross-react in immunoprecipitation with cultures, culture supernatants, and purified polysaccharides from Escherichia coli O86:K62 and O6:K2 but not with those fractions from E. coli O6:K-. Antibodies to N. meningitidis group H polysaccharide could be absorbed completely with E. coli K62 and partly with E. coli K2 bacteria but not with E. coli K- bacteria. N. meningitidis H and E. coli K2 and K62 polysaccharides share the structure -phosphate----galactose (Gal)p----glycerol (Gro)-.

Cross Reactions↗
PubMed1987

Mitogen induced lymphoproliferative responses and lymphocyte sub-populations in patients with sickle cell disease.

Mitogen induced lymphoproliferative responses and lymphocyte sub-populations were studied in a group of sickle cell disease (SCD) patients with homozygous SS hemoglobinopathy. Even though the response to a sub-optimal dose of Con A (0.5 microgram/ml of culture) was significantly decreased in patients with SCD, the proliferative responses to optimal doses of Con A, to PHA and to PWM were preserved in the patients. Addition of indomethacin to the cultures increased to a more significant degree the response to Con A of lymphocytes from patients than from the normal controls. Study of the mononuclear cell subsets indicated that the relative and absolute numbers of B lymphocytes as well as those of monocytes were significantly increased in the patients' group. The percentage of T3+ lymphocytes was found decreased in SCD. However, a rise in the number of T11+ and T4+ lymphocytes as well as in the helper/suppressor cell ratio was observed in the patients as compared to controls.

Anemia, Sickle Cell↗
PubMed1980

Effects of sublethal dose exposure to dieldrin on Rhodnius prolixus (Hemiptera: Reduviidae) under laboratory conditions.

The effects of a sublethal dose of Dieldrin (7.2 x 10(-5) g/day) were evaluated on oxygen consumption, survivorship, moulting and reproduction of Rhodnius prolixus. No difference was found in oxygen consumption between treated and control male insect. Survivorship proved to be very much affected by the sublethal exposure, but this was strongly dependent on the feeding stage of the individuals. Moulting times were prolonged by 2 to 3 days depending on the instar, but the number of individuals that succeeded in moulting was not affected. Total number of eggs laid by an average female was not affected, but the treated females layed fewer eggs in the first three weeks after feeding, and more eggs in the following weeks, than the untreated females. Possible physiological mechanisms that explain our results are related to the proteolytic activity of the midgut, to an interference with the hormonal system, to an insecticide hormoligasis effect, and to an interference with the ovarian follicles development. In terms of vector control these effects provide an alternative way of repopulating a sprayed house.

Animals↗
PubMed1975

Experimental glomerulonephritis in the rat induced by antibodies directed against tubular antigens. II. Influence of medication with prednisone and azathioprine: a histologic and immunohistologic study at the light microscopic and the ultrastructural level.

In this paper, the effect of the administration of prednisone and azathioprine on an experimental immune complex glomerulonephritis is studied. During the observation period of 3 months, it appeared that prednisone had no effect either on the morphology of glomerulonephritis or on the proteinuria caused by it. Azathioprine, especially when given 4 days before or simultaneously with the induction of the experimental immune complex glomerulonephritis, showed a clear effect on the morphology of the glomerulonephritis as well as on the proteinuria. The damage to the glomerular basement membrane as a result of deposition of immune complexes was less and the proteinuria was significantly lower. The effect of azathioprine was not present when given 10 days after the induction of glomerulonephritis, at a time when the autologous phase had already developed.

Animals↗
PubMed1975

Experimental glomerulonephritis in the rat induced by antibodies directed against tubular antigens. I. The natural history: a histologic and immunohistologic study at the light microscopic and the ultrastructural level.

A new form of experimental immune complex glomerulonephritis is described which is induced by one single injection of heterologous antibody directed against antigens present in the brush border of the proximal tubules of the rat kidney. In this model, antigen-antibody complexes are deposited as early as 3 hours after injection of the heterologous antiserum. The first localization of these complexes is seen in the dense layer of the glomerular basement membrane. Later, they move up to the lamina rara externa and stay there for at least 3 months. This model is easily reproducible and offers possibilities for studying the effects of medication on the deposition of immune complexes.

Animals↗
PubMed1975

Focal and segmental glomerular hyalinosis and sclerosis in the rat.

A glomerular disease spontaneously developing in Wistar rats was studied by light and electron microscopy and by immunofluorescence techniques. The disease is characterized by the local subendothelial deposition of hyaline material leading to increase of mesangial matrix and the development of adhesions. Immunofluorescence shows deposition of complement and IgM and to a lesser degree also of IgG in these lesions. There is a constant relationship of these early changes with the vascular pole of the glomerulus. It is confirmed that female rats are resistent to the disease as are male rats fed a sodium-deficient diet. A higher protein excretion was found in normally fed male rats as compared to female rats and to rats on a sodium-deficient diet. These differences already existed before the normally fed male rats developed glomerular disease. From these studies it is suggested that an appropriate name for this disease would be focal and segmental glomerular hyalinosis and sclerosis and that hemodynamic factors could be an important etiologic mechanism. The histopathology of the disease bears a striking resemblance to focal sclerosing glomerulopathy with segmental hyalinosis sometimes found in kidneys of patients with an idiopathic nephrotic syndrome.

Animals↗