Improvement of non-steroidal anti-inflammatory drug-induced gastrointestinal symptoms during proton pump inhibitor treatment: are G-protein ß3 subunit genotype, Helicobacter pylori status, and environmental factors response modifiers?

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) are associated with significant upper and lower gastrointestinal (GI) morbidity. AIM: To determine the efficacy and safety of pantoprazole versus placebo in controlling GI symptoms during treatment with NSAIDs and to evaluate the influence of potential response modifiers. METHODS: 800 patients with GI complaints during NSAID treatment were randomized to pantoprazole 20 mg once daily or placebo for 4 weeks in this double-blind, multicenter trial. Assessments included the difference in cumulated overall symptom load of any GI complaint during treatment (primary endpoint), proportion of days without GI symptoms, and influence of risk factors such as gender, age, alcohol consumption, smoking, Helicobacter pylori status, and GNB3 genotype SNP rs5443 (825C>T) on symptom load. RESULTS: At 4 weeks, cumulated overall symptom load was significantly lower in pantoprazole than placebo recipients [p < 0.0001; intent-to-treat (ITT)]; the effect was statistically significant after 7 days' treatment. Pantoprazole versus placebo recipients had 54 versus 29% of days without GI symptoms (p < 0.0001; ITT). Neither common risk factors nor GNB3 genotype were significantly associated with therapeutic response, while GNB3 825TT versus CT was associated with a significantly higher baseline symptom load (p < 0.05). CONCLUSION: In the population studied, treatment with the proton pump inhibitor pantoprazole significantly improves GI symptoms during NSAID therapy, irrespective of the risk factors investigated or GNB3 genotype.

Bloodstream- versus tick-associated variants of a relapsing fever bacterium.

The relapsing fever spirochete, Borrelia hermsii, alternates infections between a mammal and a tick vector. Whether the spirochete changes phenotypically in the different hosts was examined by allowing the tick vector Ornithodoros hermsi to feed on mice infected with serotype 7 or serotype 8 of B. hermsii. Upon infection of ticks, the spirochetal serotype-specific variable major proteins (Vmps) 7 and 8 became undetectable and were replaced by Vmp33. This switch from a bloodstream- to tick-associated phenotype could be induced in culture by a decrease in temperature. After tick-bite transmission back to mice, the process was reversed and the spirochetes resumed expression of the same Vmp present in the previous infectious blood meal.

Role of the Yersinia pestis hemin storage (hms) locus in the transmission of plague by fleas.

Yersinia pestis, the cause of bubonic plague, is transmitted by the bites of infected fleas. Biological transmission of plague depends on blockage of the foregut of the flea by a mass of plague bacilli. Blockage was found to be dependent on the hemin storage (hms) locus. Yersinia pestis hms mutants established long-term infection of the flea's midgut but failed to colonize the proventriculus, the site in the foregut where blockage normally develops. Thus, the hms locus markedly alters the course of Y. pestis infection in its insect vector, leading to a change in blood-feeding behavior and to efficient transmission of plague.

Ectoparasites (sucking lice, fleas and ticks) of small mammals in southeastern Kenya.

During 1998-2000, at least 14 species (n = 309) of small mammals were live-trapped and examined for ectoparasites in moist forests of the Taita and Shimba Hills and drier savannah habitats of Nguruman, southeastern Kenya. Ectoparasites were recorded from 11 species of mammals. Five species of sucking lice [Hoplopleura inexpectans Johnson, H. intermedia Kellogg & Ferris, Polyplax reclinata (Nitzsch), P. waterstoni Bedford and Schizophthirus graphiuri Ferris], six species of fleas (Ctenophthalmus leptodactylous Hubbard, Dinopsyllus grypurus Jordan & Rothschild, D. lypusus Jordan & Rothschild, Hypsophthalmus campestris Jordan & Rothschild, Listropsylla basilewskyi Smit and Xiphiopsylla lippa Jordan) and at least six species of ticks (Amblyomma sp., Haemaphysalis sp., Ixodes sp., I. alluaudi Neumann, I. cumulatimpunctatus Schulze, I. muniensis Arthur & Burrow and Rhipicephalus sp.) were recorded from these hosts. Four of the five species of sucking lice were host specific whereas P. reclinata was recorded from two different species of white-toothed shrews, Crocidura spp. Although fleas and ticks were less host specific, C. leptodactylous, D. grypurus and I. cumulatimpunctatus were only recorded from the murid rodent Praomys delectorum (Thomas), Amblyomma sp. was only recorded from the nesomyid rodent Beamys hindei Thomas, Rhipicephalus sp. was only recorded from the murid Lemniscomys striatus (L.) and I. muniensis was only recorded from the dormouse Graphiurus microtis (Noack). More species of ectoparasites and significantly greater infestation prevalences were recorded from small mammals in moist habitats compared with those from the savannah habitat. At least one of the fleas recorded, D. lypusus, is a known vector of Yersinia pestis Lehmann & Neumann, the causative agent of plague, which is present in the region.

Homology between Borrelia burgdorferi OspC and members of the family of Borrelia hermsii variable major proteins.

Synthesis of the Borrelia burgdorferi outer surface protein C (OspC) is quite variable. We have cloned and sequenced the ospC gene from B. burgdorferi isolate CA-11.2A, a clone in which ospC expression varies. The 5' flanking region of the gene contains at least two consensus promoter regions, as well as two large overlapping inverted repeats. Sequence comparison to other OspC proteins indicated that the CA-11.2A OspC is as closely related to OspC from two different genospecies of Lyme disease spirochetes as it is to OspC from the prototype B. burgdorferi strain, B31. Comparisons of the OspC amino acid (aa) sequence with those in aa sequence databases revealed partial identity with the variable major proteins Vmp3 and Vmp24 of B. hermsii, a causative agent of tick-borne relapsing fever. An ospC probe hybridized to B. hermsii restriction fragments and linear plasmids that also were recognized by the vmp3 and vmp24 probes. OspC and these Vmp appear to be related, but their synthesis is regulated differently in the two species of spirochetes. This represents a fascinating example of the evolution of the number, position, regulation and perhaps function of homologous genes in two related pathogens. These parameters may relate to characteristic properties of the pathogens and their separate tick vectors.

1-[[[5-(substituted phenyl)-2-oxazolyl]methylene]amino]-2,4- imidazolidinediones, a new class of skeletal muscle relaxants.

A series of 1-[[[5-(substituted phenyl)-2-oxazolyl]methylene]amino]- 2,4-imidazolidinediones (6a-t) was synthesized, and the compounds were evaluated for direct skeletal muscle inhibition in the pithed rat gastrocnemius muscle preparation. The correctness of structural assignment of the new series was verified by alternate, unequivocal synthesis of one representative structure (6f). The phenyloxazoles 6d, 6g, 6j, 6k, and 6l exhibited significant skeletal muscle relaxant activity when administered intravenously and orally. The skeletal muscle relaxant effect of these five compounds is similar to that of other direct-acting skeletal muscle relaxants. The oxazole moiety proved to be an acceptable isosteric replacement for furan, as the biological activity in the oxazole series was retained. The synthesis of this new class of compounds is described, and pharmacologic evaluation data are presented. A discussion of structure-activity relationships is also presented.

Synthesis and comparative skeletal muscle relaxant activity of some 2,4-imidazolidinediones and their corresponding 5-hydroxy-2,4-imidazolidinediones.

A series of 5-hydroxy substitution products of 2,4-imidazolidinediones, including the 5-hydroxy metabolite of the skeletal muscle contraction antagonist, dantrolene sodium, has been synthesized and evaluated for skeletal muscle relaxant activity. Most of these analogues are active in vivo with iv administration and in vitro. While two analogues are also active by oral and ip administration, only 1-[[[5-(3,4-dichlorophenyl)-2-furanyl]methylene]amino]-5-hydroxy-2,4-imidazolidinedione is sufficiently active in inhibiting the Straub tail in mice. However, none of these analogues has a muscle relaxant efficacy index greater than 1, comparable to dantrolene.

Antigenic variation and strain heterogeneity in Borrelia spp.

Antigenic variation and strain heterogeneity have been demonstrated for the pathogenic Borrelia species, i.e. B. burgdorferi and the relapsing fever borreliae. In relapsing fever, new borrelia serotypes emerge at a high rate spontaneously, a mechanism that is caused by DNA rearrangements on linear plasmid translocating genes coding for variable major proteins from previous silent to expression sites (i.e. from inner sites to telomeric sites of the plasmid). As a result of this variation, the borreliae escape the immune response of the host, thus leading to the relapse phenomenon. In B. burgdorferi, which is the causative agent of the multisystem disorder Lyme borreliosis, there is also a growing body of findings that antigenic variation is involved in pathogenesis of the disease. Phenotypic variation of strains in vitro concerns the size and the amount of surface-associated proteins (OspA, OspB and pC). There are indications that OspA and OspB truncations are due to deletions within the ospAB operon caused by recombination events, and that OspA/OspB-less mutants lack the 49-kb plasmid that bears the ospAB operon. With the increasing number of isolates obtained from various geographic and biological sources, it became apparent that B. burgdorferi is immunologically and genetically more heterogeneous, as previously believed. The major outer surface proteins OspA and OspB (which have been efficient antigens in vaccine studies) are heterogeneous at a genetic level. The same degree of genetic non-identity was observed for the pC protein. Other proteins like flagellin and the highly specific immunodominant p100 range protein show a lower degree of non-identity. Recombinant OspA, pC, p100 range protein and flagellin have been hyperexpressed in E. coli and these proteins are immunologically reactive. This allows further research for development of vaccines and diagnostic tools. B. burgdorferi isolates have been investigated with genotyping (DNA hybridization, PCR and 16S rRNA analysis) as well as serotyping by various authors. Comparison of the different methods has shown good agreement when the same strains have been investigated. No correlation could be found between different phenotypic and genotypic groups with respect to the ability to cause arthritis in SCID mice. A serotyping system based on immunological differences in OspA detected by a panel of monoclonal antibodies has been proposed. Serotyping a large number of B. burgdorferi isolates has shown a striking predominance of the OspA serotype 2 among European isolates from human skin, in contrast to isolates from ticks or CSF.(ABSTRACT TRUNCATED AT 400 WORDS)

Fleas on roof rats in six areas of Los Angeles County, California: their potential role in the transmission of plague and murine typhus to humans.

Roof rats (Rattus rattus) in southern California are rarely involved with plague epizootics and murine typhus. Little evidence exists implicating these rodents as sources of human infection. This might be explained by the absence of fleas capable of transmitting these 2 diseases. From February 1981 through January 1982, roof rats were live-trapped and examined for fleas each month in 4 areas of Los Angeles County. Two other areas were trapped for 9 and 3 months respectively. Areas sampled were in or near the suburban-wilderness fringe where plague and murine typhus occur, and where roof rats coexist with a variety of wild and domestic mammals and humans. From 1,206 roof rats, 827 fleas belonging to eight species were collected. Leptopsylla segnis (54%) and Nosopsyllus fasciatus (39%) were the most abundant and together comprised 93% of all fleas. Xenopsylla cheopis was not found. The relative abundance and diversity of fleas on roof rats varied considerably between areas, making it difficult to predict flea diversity and abundance in unsurveyed areas where similar conditions exist. However, the overall low flea indices and the absence of X. cheopis help to explain why roof rats in Los Angeles County are rarely involved with plague and murine typhus.

Recombinant capsular antigen (fraction 1) from Yersinia pestis induces a protective antibody response in BALB/c mice.

Yersinia pestis produces a glycoprotein capsule, the biosynthesis of which appears to be temperature dependent. The fraction I (F1) component of this capsule is specific to Y. pestis and the detection of F1 antibodies is the basis for several serological tests. We report the cloning of the F1 gene and its expression in Escherichia coli using the phagemid vector lambda ZAPII and a F1-specific monoclonal antibody. The recombinant F1 antigen had a molecular weight of 17 kDa, which proved to be identical to that of the F1 antigen produced by Y. pestis. The recombinant cells produced F1 antigen at 37 degrees C but only minimal amounts at 27 degrees C, suggesting that the genetic features affected by temperature in Y. pestis may be operating in the E. coli clone. It is not known if their similar molecular weights reflect the glycosylated nature of both proteins. F1 antigen purified from the E. coli recombinant induced a protective immune response in BALB/c mice challenged with up to 10(5) virulent Y. pestis. The resistance of immunized mice to plague infection correlated with high titers of F1 antibody. The cloned gene expresses an immunogenically competent F1 antigen suitable for use in plague serodiagnostics and vaccine development.

Estimation of vector infectivity rates for plague by means of a standard curve-based competitive polymerase chain reaction method to quantify Yersinia pestis in fleas.

The prevalence of infectivity within a vector population is a critical factor in arthropod-borne disease epidemiology but it is difficult to estimate. In the case of bubonic plague, infective flea vectors contain large numbers of Yersinia pestis within a bacterial mass that blocks the flea's foregut, and only such blocked fleas are important for biologic transmission. A bacterial quantitation method could therefore be used to assess the prevalence of plague-infective (blocked) fleas in a population. We developed a standard, curve-based, competitive polymerase chain reaction (PCR) procedure to quantitate Y. pestis in individual fleas. The quantitative PCR (Q-PCR) method equaled a colony count reference method in accuracy and precision when evaluated using mock samples and laboratory-infected fleas. The Q-PCR was more reliable than colony count, however, for field-collected fleas and for blocked fleas collected after their death. In a sample of fleas collected from a prairie dog colony in the aftermath of a plague epizootic, 48% were infected but less than 2% contained numbers of Y. pestis indicative of blockage. The method provides a means to monitor plague epizootics and associated risks of flea-borne transmission to humans, and is applicable to the study of other vector-borne diseases.

Failure of intragastrically administered Yersinia pestis capsular antigen to protect mice against challenge with virulent plague: suppression of fraction 1-specific antibody response.

We evaluated the Yersinia pestis capsular (fraction 1 [F1]) antigen as a potential oral immunogen in mice. We found that single doses of as much as 0.4 mg of F1, administered by intragastric (ig) intubation, were unprotective and did not stimulate production of detectable levels of specific antibody. Three weekly ig doses resulted in low serum antibody levels that also did not provide protection against challenge with virulent Y. pestis. Assays of type-specific antibody following intubation and subsequent challenge with a subcutaneous inoculation of F1 revealed that the quantity of antigen intubated and the secondary IgG2a antibody levels were inversely related, suggesting the induction of tolerance to intragastrically administered F1 antigen. Transfer of spleen cells from intubated mice to F1 immune recipients failed to demonstrate suppression of specific antibody, indicating that the immune tolerance observed in intubated mice was not due to a T suppressor cell-mediated effect. The results of this study indicate that Y. pestis F1 antigen is not likely to be an efficacious immunogen for oral vaccination of mice against plague.

DNA typing of rickettsiae in naturally infected ticks using a polymerase chain reaction/restriction fragment length polymorphism system.

We used the polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) rickettsial typing system of Regnery and others to rapidly identify rickettsiae in naturally infected ticks. Unlike previously described methods, our PCR assays type rickettsiae directly from tick tissues without first isolating the organisms. We collected 226 adult Dermacentor andersoni ticks in the Bitterroot Mountains of western Montana and analyzed them for possible rickettsial infection by hemolymph test using the Gimenez stain. Thirteen (5.8%) of these ticks were positive by hemolymph test and selected for further analysis using the above PCR/RFLP typing system. The PCR assays performed using the first primer set (RpCS) resulted in amplification of fragments of the predicted size from nine of the 13 hemolymph test-positive tick samples. Only four of these nine tick samples were also positive in similar PCR assays performed with a second primer set (Rr190) that is presumed to be spotted fever group specific. The RFLP analyses of material amplified from these four ticks indicated they were infected with Rickettsia rickettsii (one sample) and R. rhipicephali (three samples). The PCR/RFLP analyses of the five PCR-positive tick samples that were positive only in assays performed with the RpCS primer set indicated that these ticks were infected with R. bellii. The remaining four of 13 hemolymph test-positive tick samples gave negative PCR results with both the RpCS and Rr190 primer sets. Infected hemocytes from these PCR-negative ticks contained organisms of distinctive bacillary morphology that appeared similar to those described previously as long forms, and it is possible that these organisms belong to a genus other than Rickettsia. We also examined established laboratory isolates of tick-borne rickettsiae from different regions of North America to determine whether this typing system produces consistent results. Multiple isolates of R. montana (nine isolates), R. bellii (five isolates), R. rickettsii (Hlp-like) (four isolates), and R. canada (two isolates) were tested and no significant variations in PCR/RFLP patterns were observed between members of the same serotypes. However, among the five isolates of R. rhipicephali tested, two slightly different RFLP patterns were noted. Our results suggest that this PCR/RFLP typing scheme has wide applicability for identifying rickettsiae directly from D. andersoni or D. variabilis tick tissues.

Nucleotide sequence and analysis of the gene in Borrelia burgdorferi encoding the immunogenic P39 antigen.

The P39 antigen is a specific, highly conserved, and immunogenic protein of Lyme disease spirochetes, Borrelia burgdorferi sensu lato. The nucleotide sequence of the gene encoding this protein was determined and found to be the first of two tandemly arranged open reading frames located on the spirochete's chromosome. These two open reading frames were designated bmpA for the gene encoding P39 and bmpB for the gene encoding the putative protein ORF2 encoded by the second open reading frame. The nucleic acid sequence identity for the two open reading frames was 62% while their deduced amino acid sequences were 52% identical. Comparison to sequence data bases demonstrated that the deduced amino acid sequences of both P39 and ORF2 were homologous to TmpC, a putative outer or cytoplasmic membrane lipoprotein of the syphilis spirochete, Treponema pallidum.

Clinical implications of delayed growth of the Lyme borreliosis spirochete, Borrelia burgdorferi.

Lyme borreliosis, a spirochetal infection caused by Borrelia burgdorferi, may become clinically active after a period of latency in the host. Active cases of Lyme disease may show clinical relapse following antibiotic therapy. The latency and relapse phenomena suggest that the Lyme disease spirochete is capable of survival in the host for prolonged periods of time. We studied 63 patients with erythema migrans, the pathognomonic cutaneous lesion of Lyme borreliosis, and examined in vitro cultures of biopsies from the active edge of the erythematous patch. Sixteen biopsies yielded spirochetes after prolonged incubations of up to 10.5 months, suggesting that Borrelia burgdorferi may be very slow to divide in certain situations. Some patients with Lyme borreliosis may require more than the currently recommended two to three week course of antibiotic therapy to eradicate strains of the spirochete which grow slowly.

Xenopsylla bantorum is an east African subspecies of X. cheopis (Siphonaptera: Pulicidae).

The geographic distribution, host association, and male genital morphology of Xenopsylla bantorum Jordan were examined and compared with the Nilotic and Oriental "strains" of Xenopsylla cheopis (Rothschild). The more acute shape of the ninth sternite separates X. bantorum from all types of X. cheopis; however, the length of the first process of the male's clasper and the number of setae on this process are significantly different among all three groups; the Nilotic strain of X. cheopis is intermediate to the others. Specimens collected from both wild and commensal rodents in Nakuru, Kenya, were all X. bantorum, suggesting that X. cheopis present early in the century that resulted from introductions on Rattus rattus had been absorbed by the native X. bantorum population. These factors and a review of opinions by others concerning the status of X. bantorum demonstrate that this flea is not specifically distinct from X. cheopis. The trinomial X. cheopis bantorum is erected. Furthermore, the Nilotic and Oriental "strains" of X. cheopis are distinguishable morphologically solely by the length of the male's first process.

Sex ratio and phoretic mites of fleas (Siphonaptera: Pulicidae and Hystrichopsyllidae) on the Nile grass rat (Arvicanthis niloticus) in Kenya.

The sex ratio of fleas and their phoretic mites associated with the Nile grass rat, Arvicanthis niloticus (Desmarest), were studied during 14 mo in a grassland community of Lake Nakuru National Park, Kenya. Females of the fleas Dinopsyllus lypusus Jordan & Rothschild, Ctenophthalmus calceatus cabirus Jordan & Rothschild, and Xenopsylla cheopis bantorum Jordan infested more grass rats and in greater numbers than did males. Phoretic hypopi (hetermorphic deutonymphs) of two species of mites, Psylloglyphus uilenbergi Fain and Paraceroglyphus xenopsylla Fain & Schwan, varied seasonally in their abundance on fleas and utilized female fleas over male fleas for their major source of transport. Additionally, the mites were very host specific with nearly 100% of those identified on D. lypusus and C. calceatus cabirus being P. uilenbergi and 89% of the mites identified on X. cheopis bantorum being P. xenopsylla. This level of specificity suggests that these mite-flea associations are highly evolved. The importance of female fleas as hosts for transporting mites also suggests that female-biased sex ratios of fleas on their hosts may be caused, in part, by females being more important as dispersers within flea populations.

Positional isomer of the muscle relaxant dantrolene.

3-[[5-(P-Nitrophenyl) furfurylidene]amino]hydantoin, a position isomer of dantrolene, was synthesized and evaluated for skeletal muscle relaxant activity.

5-chloro-2-pyrimidinyl analog of dantrolene.

1-[5-(5-Chloro-2-pyrimidinyl)furfurylidene]amino-hydantoin, a structural analog of the skeletal muscle contraction antagonist dantrolene, was synthesized and found to have no skeletal muscle relaxant activity.

Synthesis of 5-hydroxy-1-((5-(p-nitrophenyl)furfurylidene)-amino) hydantoin, a metabolite of dantrolene.

The synthesis and structural elucidation of 5-hydroxyl-1-[[5-(p-nitrophenyl)furfurylidene]amino]hydantoin, a compound proposed as a metabolite of dantrolene sodium, are reported. In addition, a chromatographic comparison of the biological and synthesized materials is made.