RESUMEN

AIMS: The study aim was to determine the presence of total and faecal coliforms on kitchen surfaces, in tap water and on the hands of caregivers in households on both sides of the US-Mexico border. METHODS AND RESULTS: Samples were collected in 135 randomly selected households in Ciudad Juarez, Mexico, and El Paso, Texas. Different surfaces throughout the kitchen and head of households' hands were sampled using sterile cotton swabs moistened in D/E neutralizing solution. Sponge/dishcloth and drinking water samples were also obtained. Total and faecal coliforms were enumerated on m-Endo LES and mFC respectively. Total coliforms and Escherichia coli in drinking water samples were enumerated in accordance with the Quanti-Tray method. Sponge/dishcloth samples were the most commonly contaminated kitchen sites, followed by countertops and cutting boards. We recovered faecal coliforms from 14% of the hands of child caregivers, and this indicator was moderately associated with self-reported failure to wash hands after using the toilet (OR = 3.2; 95% CI: 0.9, 11.1). CONCLUSIONS: Hand washing should continue to be emphasized, and additional interventions should be directed to specific kitchen areas, such as sponges/dishcloths, tables/countertops and cutting boards. SIGNIFICANCE AND IMPACT OF THE STUDY: There is a need for additional interventions regarding kitchen sanitation.

Asunto(s)

RESUMEN

Taenia solium and T. saginata are zoonotic tapeworms of substantial medical and economic importance. Although human taeniasis is widely recognised as an endemic problem in Mexico, its presence in the United States is poorly understood. The first population-based study to estimate the prevalence of human infection with Taenia tapeworms along the Texas-Mexico border has recently been conducted. Households were interviewed in the Texan city of El Paso and in the neighbouring Ciudad Juárez, in Mexico. Faecal samples from household members were then checked for Taenia eggs by flotation and/or for Taenia copro-antigens in an ELISA. The overall prevalence of taeniasis in this border region was found to be 3% but, compared with the residents of Juárez, El Paso residents were 8.6-fold more likely to be tapeworm carriers. The interviews revealed some important differences between the two study sites, particularly the more frequent use of anthelminthic drugs on the Mexican side of the border. These findings have implications in terms of the planning of effective health-education campaigns to decrease the prevalence of taeniasis in the human populations along the Texas-Mexico border.

Asunto(s)

RESUMEN

p38 is a member of the mitogen-activated protein (MAP) kinase family. Activation (phosphorylation) of p38 acts as a switch for the transcriptional and translational regulation of a number of proteins, including the proinflammatory cytokines. Investigation of a set of small peptides revealed that, as with protein substrates, p38-alpha behaves as a proline-directed Ser/Thr MAP kinase for a peptide substrate, peptide 4 (IPTSPITTTYFFFKKK). We investigated the steady-state kinetic mechanism of the p38-alpha-catalyzed kinase reaction with EGF receptor peptide, peptide 1, as a substrate. Lineweaver-Burk analysis of the substrate kinetics yielded a family of lines intersecting to the left of the ordinate, with either ATP or peptide 1 as the varied substrate. Kinetic analysis in the presence of ADP yielded a competitive inhibition pattern when ATP was the varied substrate and a noncompetitive pattern if peptide 1 was the varied substrate. At saturating peptide substrate concentrations, inhibition by phosphopeptide product yielded an uncompetitive pattern when ATP was the varied substrate. These data are consistent with ordered binding with ATP as the initial substrate. We provide further evidence of the existence of a productive p38.ATP binary complex in that (a) activated p38-alpha has intrinsic ATPase activity, (b) ATPase and kinase activities are coupled, and (c) inhibitors of ATPase activity also inhibit the kinase activity with a similar inhibition constant. The k(cat) for the kinase reaction was lowered by 1.8-fold when ATP-gamma-S was used. Microviscosity linearly affected the k(cat) values of both the ATP and ATP-gamma-S reactions with a slope of about 0.8. These observations were interpreted to mean that the phosphoryl transfer step is not rate-limiting and that the release of product and/or enzyme isomerization is a possible rate-limiting step(s).

Asunto(s)

RESUMEN

1. The major pathological responses to Gram-negative bacterial sepsis are triggered by endotoxin or lipopolysaccharide. As endotoxin is shed from the bacterial outer membrane, it induces immunological responses that lead to release of a variety of cytokines and other cellular mediators. As part of a program aimed at developing a therapeutic agent for septic shock, we have developed E5531, a novel synthetic lipopolysaccharide antagonist. 2. As measured by release by tumour necrosis factor-alpha, human monocytes or whole blood can be activated by lipopolysaccharide, lipid A, and lipoteichoic acid (from Gram-positive bacteria). E5531 potently antagonizes activation by all these agents while itself being devoid of agonistic activity. 3. The inhibitory activity of E5531 was dependent on time of addition. When 10 nM E5531 was added simultaneously with lipopolysaccharide or 1 - 3 h before addition of lipopolysaccharide, production of tumour necrosis factor-alpha was inhibited by more than 98%. The addition of E5531 1 h after lipopolysaccharide reduced the efficacy of E5531 by 47%. 4. Antagonistic activity of E5531 was specific for lipopolysaccharide as it was ineffective at inhibiting interferon-gamma mediated NO release of RAW 264.7 cells, phorbor 12-myristate 13-acetate stimulated superoxide anion production in human neutrophils, concanavalin A stimulated mitogenic activity in murine thymocytes and tumor necrosis factor-alpha induced E-selectin expression in human umbilical vein endothelial cells. 5. E5531 as well as MY4, an anti-CD14 antibody, inhibited radiolabelled lipopolysaccharide binding in human monocytes. 6. These results support our contention that E5531 is a potent antagonist of lipopolysaccharide-induced release of tumour necrosis factor-alpha and other cellular mediators and may be an effective therapeutic agent for human septic shock due to Gram-negative bacteria.

Asunto(s)

RESUMEN

Lipid A from the photosynthetic bacterium Rhodobacter sphaeroides (RSLA) has been previously shown to antagonize many of the effects of endotoxins from more pathogenic gram-negative bacteria. We have reported on the synthesis of the proposed structure of RSLA and determined that bacterially derived RSLA is not identical to its proposed structure (W.J. Christ, P. D. McGuinness, O. Asano, Y. Wang, M. A. Mullarkey, M. Perez, L. D. Hawkins, T. A. Blythe, G. R. Dubuc, and A. L. Robidoux, J. Am. Chem. Soc. 116:3637-3638, 1994). Here we report results of analyzing the antagonistic and agonistic activities of bacterially derived RSLA in comparison with the activities of chemically synthesized material of the proposed structure of RSLA and analogs. Results indicated that all compounds were approximately equally potent at inhibiting endotoxin-induced release of tumor necrosis factor alpha from human monocytes and human whole blood as well as endotoxin-induced generation of nitric oxide in murine macrophages. In addition, all compounds were of equivalent potencies at inhibiting the binding of 125I-labelled lipopolysaccharide derivatized with 2-(p-azido-salicylamido) ethyl-1-3'-dithiopropionate to murine macrophages. Higher concentrations of bacterially derived RSLA (10 to 100 microM) were agonistic in human and murine assays. In gamma interferon-treated murine macrophages, agonism was exhibited at concentrations as low as 100 nM. In contrast, all synthetic materials were either dramatically less agonistic or devoid of agonistic activity when tested at concentrations as high as 100 microM. It is possible either that bacterially derived RSLA contains a small amount of a highly agonistic impurity or that the agonistic activity of RSLA is intrinsic to its molecular structure. In either case, these biological results support our previous report concluding that biologically derived RSLA is not identical to synthetic material of its proposed structure.

Asunto(s)

RESUMEN

Lipid As from non-toxic bacteria such as Rhodobacter capsulatus and Rhodobacter sphaeroides have been shown to antagonize the immunostimulatory effects of lipid A and LPS from pathogenic bacteria. We have biologically characterized a series of synthetic LPS antagonists including the proposed structures of the lipid A and R. sphaeroides containing fatty acid side chains ester-linked to the disaccharide backbone, as well as an analog of R. capsulatus lipid A containing ether-linked alkyloxy side chains (E5531). In vitro assays utilizing LPS-stimulated human monocytes or whole blood demonstrated that low nanomolar concentrations of E5531 inhibited cellular activation as indicated by decreased release of the cytokines TNF-a, and interleukins-1, 6, and 8. E5531 also inhibited LPS-induced release of cytokines and nitric oxide from murine macrophages. Synthetic antagonists at up to 100 microM were devoid of agonistic activity in murine and human in vitro systems. In vivo, E5531 blocked induction of TNF-a by LPS and reduced LPS-induced lethality in mice. These in vitro and in vivo results indicate that E5531 may have clinical therapeutic utility as an antagonist of endotoxin-mediated morbidity and mortality.

Asunto(s)

RESUMEN

Rejection of Nippostrongylus brasiliensis in mice typically occurs by 14 days postinfection (PI). We report here on a putative BALB/c mouse strain from the University of Texas at El Paso (UTEP) animal colony that did not exhibit a normal pattern of self-cure. Following subcutaneous inoculation with approximately 500 third-stage larvae of N. brasiliensis, the parasite was present in substantial numbers in UTEP BALB/c mice on days 21 and 28 PI and in low numbers through day 70 PI regardless of host sex. Normal self-cure was observed using identical techniques in 2 other BALB/c strains and a CFW strain. Hence, the UTEP BALB/c mouse provides a unique tool to examine the immune response to N. brasiliensis.

Asunto(s)

Asunto(s)

Asunto(s)

RESUMEN

Results suggest that infection with Eimeria nieschulzi (Protozoa) interferes with splenocyte proliferation induced by infection with Nippostrongylus brasiliensis (Nematoda).

Asunto(s)

RESUMEN

The issue of extraintestinal infection by Eimeria nieschulzi in the rat was addressed by transferring various tissues from infected to uninfected rats by mouth. All 6 rats receiving liver, spleen, or small intestine from rats killed at 3 or 8 hr postinoculation (PI), and all 5 rats receiving spleen and small intestine from rats killed 8 days PI, showed infections. Rats receiving tissues from rats killed at 8 days PI showed infections 24 hr later, indicating that fourth-generation merozoites were transferred. This is the first demonstration of an extraintestinal rodent eimerian.

Asunto(s)

RESUMEN

PGE1 and PGE2 have been reported to enhance natural expulsion of Nippostrongylus brasiliensis, a nematode parasite, from the intestine of the rat. Mucus production may also be a key element of worm rejection. Our study attempts to determine if 1) PGE1 or PGE2 alter the normal course of infection with N. brasiliensis in rats, 2) a known mucous enhancing drug, acetazolamide, can augment the rate of worm expulsion, and 3) combinations of prostaglandins and acetazolamide affect N. brasiliensis in the rat. Rats were inoculated with approximately 1,000 infective larvae of N. brasiliensis. Animals were administered, intraduodenally, one of the following: 0.2 ml 0.9% NaCl; 0.2 ml 100% ethanol; 250 micrograms PGE1/0.2 ml 100% ethanol; 250 micrograms PGE2/0.2 ml 100% ethanol; 250 micrograms acetazolamide/0.2 ml 100% ethanol; 250 micrograms PGE1 or PGE2 + 250 micrograms acetazolamide/0.2 ml 100% ethanol. These solutions were given in a single bolus on day 6 postinoculation (PI) or twice daily on days 6-9 PI. Following these treatments the number of parasite ova per gram feces per day for days 6-10 PI and numbers of worms present at necropsy on day 10 PI were determined. Treatment with prostaglandins or acetazolamide or both failed to adversely affect egg deposition by adult female worms or the number of worms in the small intestine. These results do not support the involvement of prostaglandins in the expulsion of N. brasiliensis from the host intestine.

Asunto(s)

RESUMEN

Interspecific interactions between Nippostrongylus brasiliensis and Eimeria nieschulzi were studied by measuring fecal lysophospholipase (LYPH) activity and relative numbers of peripheral eosinophils in rats singly or concurrently infected with one or both parasite species. Three groups of 10 rats each were inoculated with 2 X 10(3) N. brasiliensis L3 larvae and/or 5 X 10(5) E. nieschulzi sporulated oocysts. Groups 1 and 2 were infected with E. nieschulzi or N. brasiliensis, respectively. Group 3 rats were infected first with N. brasiliensis, followed on day 8 postinoculation (PI) with E. nieschulzi. Each rat served as its own control. Results revealed LYPH levels rose steadily in Group 2 rats, reaching significant peaks on days 10 and 12 PI before decreasing to control levels. Lysophospholipase activity in Groups 1 and 3, however, did not differ from control values. Group 2 rats also demonstrated peripheral eosinophilia, with peak values occurring on days 10, 12, 14, and 16 PI, while rats in Groups 1 and 3 exhibited no eosinophilia. These results demonstrate that E. nieschulzi suppressed intestinal LYPH activity and relative peripheral eosinophilia and demonstrate that a host's immune response to a single parasite may be significantly altered when a second parasite species is present.

Asunto(s)

RESUMEN

Four groups of 60 rats each were used to examine interspecific interactions between Eimeria nieschulzi and Nippostrongylus brasiliensis. Rats in group 1 served as uninoculated controls. Group 2 rats were each injected subcutaneously with 2.0 X 10(3) L3 larvae of N. brasiliensis. Group 3 rats were each inoculated per os with 2.5 X 10(5) sporulated oocysts of E. nieschulzi. Rats in group 4 were first infected with 2.0 X 10(3) larvae of N. brasiliensis and, at 8 days postinoculation, with 2.5 X 10(5) oocysts of E. nieschulzi. Ten animals from groups 1-3 were sacrificed at 4-day intervals postinoculation and group 4 rats were sacrificed at 4-day intervals beginning after the secondary infection. Blood smears were prepared from each animal to determine differential blood cell counts, bone marrow was examined at the times of peak infection for absolute and relative numbers of eosinophils, portions of the duodenum and jejunum were examined histologically for mast cells, and feces obtained from the cecum and large intestine were examined for ova/gram of feces. Results revealed that relative numbers of peripheral neutrophils and monocytes became elevated during the course of infection for all infected animals, and rats infected with the helminth only also had elevated eosinophil levels. However, rats infected singly with E. nieschulzi, or concurrently with the coccidium and helminth, had peripheral eosinophil levels that were not significantly different from controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Asunto(s)

RESUMEN

Results suggest that malabsorption of amino acids which occurs during Eimeria nieschulzi and Nippostrongylus brasiliensis infections in rats is not due to impairment by intestinal inflammation of gamma-glutamyl transpeptidase activity.

Asunto(s)

Asunto(s)

RESUMEN

Ova production in Nippostrongylus brasiliensis infected rats was significantly greater than in rats singly infected with the helminth when Eimeria separata infections were introduced 4, 6 and 11 days postinoculation with N. brasiliensis. Patent periods were unaltered during concurrent infections. These results suggest that the presence of E. separata affects helminth fecundity but does not increase N. brasiliensis longevity as has been shown with E. nieschulzi.

Asunto(s)

RESUMEN

Glucose absorption and net small intestinal water movement were examined in rats infected with Nippostrongylus brasiliensis at Days 4, 6, 9, 13, and 19 after inoculation. Rats were infected with 4 X 10(3) N. brasiliensis third stage larvae. The entire small intestine was divided into three segments and each segment perfused simultaneously in vivo with Krebs-Ringer phosphate buffer containing 80 mM glucose, 6 X 10(5) dpm/ml [3H]glucose, and 6.2 X 10(3) dpm/ml [14C]polyethylene glycol. Rats perfused on Days 6, 9, 13, and 19 after inoculation showed a significant (P less than 0.05) decrease in glucose absorption rates from all three segments of the small intestine when compared to uninfected controls. In the three segments of uninfected rat small intestine and those perfused on Days 4, 13, and 19 after inoculation, net absorption of water occurred. However, in the proximal and distal segments perfused on Day 6 and the proximal segment perfused on Day 9, net water movement into the lumen occurred. This is the first report of depressed glucose absorption along the entire length of the small intestine during nippostrongylosis and contradicts previous reports of unaltered net glucose absorption in response to this parasite.

Asunto(s)

RESUMEN

Interspecific interactions between Nippostrongylus brasiliensis and Eimeria nieschulzi were studied by measuring parasite fecundity and patency in rats concurrently infected with both species. Nine groups of five rats each were inoculated with either 4 x 10(3) N. brasiliensis larvae or 2.6 x 10(5) E. nieschulzi sporulated oocysts or both. Groups 1 and 2 served as singly-infected controls. Group 3 rats were infected simultaneously with both parasites. Rats in Groups 4 to 8 were infected first with N. brasiliensis and later with E. nieschulzi on days 3, 4, 8, 9, and 14 PI. Rats in Group 9 were infected with E. nieschulzi and then with N. brasiliensis 2 days later. Patency of N. brasiliensis infections was extended significantly (P less than or equal to 0.05) beyond singly-infected controls in all groups with concurrent infections except Group 3, whereas ova production was significantly greater than that in singly-infected controls only when both parasites were administered simultaneously (Group 3). Patency of E. nieschulzi was significantly shorter in Group 7 rats and longer in Group 9 rats compared to that of singly-infected controls. Total oocyst production was unaltered except for Groups 5 and 7 in which there was a significant reduction. These results demonstrate that the endogenous stages of E. nieschulzi increased N. brasiliensis longevity.

Asunto(s)

RESUMEN

Biliary tract histopathologic responses of the Mongolian jird, Meriones unguiculatus, were monitored during infection with Brachylaime microti. At 15 days postinoculation (PI), an inflammatory cell (polymorphonuclear and band neutrophil) response occurred in periductal tissue of the common bile duct at the site of oral sucker attachment; basophils and eosinophils were not observed. Capillary prominence and fibroblasts also were noted in this region. Histologic evidence suggested an immunologic response had begun by 15 days PI; massive periductal lymphocytic infiltration occurred and enlarged mesenteric lymph nodes adjacent to the pancreas contained proliferating lymphocytes. Hepatocyte vacuolation was noted at this time. By 30 days PI, the bile duct epithelium had invaginated and lymph nodes were enlarged further. At 65 days PI, worms were encapsulated in small intrahepatic ducts by fibrous tissue of host origin. Gastric peritoneal mesothelial cysts containing ova were seen in one host. Pancreatitis was not observed in response to infection with B. microti.

Asunto(s)