Seasonal prevalence of gastrointestinal parasites in desert bighorn sheep (Ovis canadensis) in northern Mexico.

This study aimed to describe the shedding pattern of gastrointestinal parasite eggs by a wild population of desert bighorn sheep (DBS; Ovis canadensis) in northern Mexico. Seventy-five fresh faecal samples were collected from the ground in each season within an hour after being expelled by these animals. The generalized linear mixed model showed that eggs per gram of faeces were highest in winter (577 ± 399) and lowest in summer (260 ± 198). Generalized linear models revealed that Strongyloides spp. predominated during most seasons with a peak in summer (85% of faecal samples analysed) and the absence of this helminth in winter. Nematodirus spp. was another helminth present in three seasons, with the presence of this nematode in 35% of the faecal samples in spring and 0% in summer. Other parasites in DBS faeces included Bunostomun spp., Trichostrongylus spp., Cooperia spp., Mecistocirrus digitatus, Haemonchus contortus, Chabertia ovina and Eimeria ovinoidalis. There were differences among seasons in the percentage of these helminths and coccidia in faecal samples for all these parasites. It was concluded that helminths egg output in DBS in a semi-arid rangeland is lowest in summer and spring and highest in autumn and winter. Furthermore, it was shown that DBS in the study site do not suffer from severe parasite burden. Therefore, this nematode parasite burden is compatible with the conservation and well-being of this particular population.

Differential immune response in mice immunized with the A, R or C domain from TcSP protein of Trypanosoma cruzi or with the coding DNAs.

In a murine model of experimental Trypanosoma cruzi (H8 strain) infection, we investigated the induction of protective immunity against the domains [amino (A), repeats (R) and carboxyl (C)] of the surface protein (SP), a member of the trans-sialidase (TS) superfamily. Recombinant proteins and plasmid DNA coding for the respective proteins were used to immunize BALB/c mice, and the humoral response and cytokine levels were analysed. Immunization with the recombinant proteins induced higher levels of anti-TcSP antibodies than immunization with the corresponding DNAs, and analysis of serum cytokines showed that immunization with both recombinant proteins and naked DNA resulted in a Th1-Th2 mixed T-cell response. Mice immunized with either recombinant proteins or plasmid DNA were infected with blood trypomastigotes. The recombinant protein-immunized mice showed a variable reduction in peak parasitemia, and most died by day 60. Only the pBKTcSPR-immunized mice exhibited a significant reduction in peak parasitemia and survived the lethal challenge. DNA-based immunization with DNA coding for the repeats domain of TcSP is a good candidate for the development of a vaccine against experimental T. cruzi infection.

Plasmid DNA immunization with Trypanosoma cruzi genes induces cardiac and clinical protection against Chagas disease in the canine model.

The only existing preventive measure against American trypanosomosis, or Chagas disease, is the control of the transmitting insect, which has only been effective in a few South American regions. Currently, there is no vaccine available to prevent this disease. Here, we present the clinical and cardiac levels of protection induced by expression to Trypanosoma cruzi genes encoding the TcSP and TcSSP4 proteins in the canine model. Physical examination, diagnostic chagasic serology, and serial electrocardiograms were performed before and after immunization, as well as after experimental infection. We found that immunization with recombinant plasmids prevented hyperthermia in the acute phase of experimental infection and produced lymphadenomegaly as an immunological response against the parasite and additionally prevented heart rate elevation (tachycardia) in the acute and/or chronic stages of infection. Immunization with T. cruzi genes encoding the TcSP and TcSSP4 antigens diminished the quality and quantity of the electrocardiographic abnormalities, thereby avoiding progression to more severe developments such as right bundle branch block or ventricular premature complexes in a greater number of dogs.

[Incrusted cystitis after Mitomicin-C]. / Cistitis incrustante tras Mitomicina C.

Incrusted cystitis is an infrequent process characterized by precipitation an incrustation of salts on the vesical mucosa. An alkanine urine is required to this precipitation. The urinary infection with urolithic activity microorganisms can also be a very important factor. We present a case of incrusted cystitis after using Mitomicine as vesical chemotherapy.

Safety and efficacy of Omniscan (gadodiamide injection) at 0.1 mmol/kg for MRI in infants younger than 6 months of age: phase III open multicenter study.

RATIONALE AND OBJECTIVES: To demonstrate that gadodiamide injection is a safe and efficient contrast agent for MRI in infants younger than 6 months of age. METHODS: The authors designed a phase III multicenter nonrandomized study using a control group. Gadodiamide injection at a dosage of 0.1 mmol/kg body weight was administered to 39 children; 20 received no contrast. The mean age was 10.6 weeks in the contrast group and 9.3 weeks in the control group. MR examinations, blood (serum creatinine, S-ASAT, S-ALAT, S-bilirubin, alkaline phosphatase) and urine (proteins, blood, others) sampling before sedation and after examination, heart rate (electrocardiography) and oxygen saturation (pulse oximetry) during examination, adverse events, and efficacy parameters were analyzed. RESULTS: In the contrast group, 18 (51.4%) children had 31 abnormal changes in one or more of the safety parameters and vital signs. In the control group there were 16 (80.0%) children with 19 abnormal changes. Gadodiamide injection had no negative influence on the safety parameters. No serious adverse events occurred, and only three clinically relevant adverse events (elevation of S-ALAT and S-ASAT, elevation of bilirubin) in two patients in the contrast group and one event (vomiting) in one patient in the control group were documented. The benefit of the contrast medium was clearly shown for all evaluated parameters. CONCLUSIONS: Gadodiamide injection is safe, well tolerated, and effective in infants younger than 6 months of age.

Humoral nitric oxide levels and antibody immune response of symptomatic and indeterminate Chagas' disease patients to commercial and autochthonous Trypanosoma cruzi antigen.

We report here the evaluation of chagasic patients for the presence and/or severity of the disease, antibody to Trypanosoma cruzi, and nitric oxide (NO) serum levels. Serum samples tested by ELISA with autochthonous and commercial antigen revealed that 10% and 7.5% of the individuals were anti-T. cruzi antibody-positive, respectively. Ten of 21 seropositive individuals had no clinical signs, the other 11 cases presented cardiomyopathy and/or mega-gastrointestinal syndromes, and three patients presented a combined form. A statistical difference (P < 0.001) in antibody titer between asymptomatic and symptomatic patients with autochthonous antigen was detected, and serum NO levels was found to be three times higher in cases than in controls. These results suggest that it is recommended to use a sole source of antigen (autochthonous) for the serodiagnosis of Chagas' disease, and that the pathogenic role of NO in this disease should be evaluated.

A beta 1 integrin-like molecule in Entamoeba histolytica.

Human invasive amoebiasis is highly destructive, causing rapid necrosis and liquefaction of all tissues reached by the trophozoites. Degradation of extracellular matrix components (EMC) has been demonstrated during invasion of the basal lamina. Pursuing the idea that trophozoites might behave similarly to other invasive cells with respect to their interaction with EMC, plasma membrane proteins biochemically or functionally related to integrins were looked for. A 140 kDa molecular mass membrane protein from Entamoeba histolytica trophozoites with the characteristics of a beta 1 integrin-like fibronectin receptor was identified.

Analysis of the hyperpolarizing effects of forskolin in guinea-pig atrial heart muscle.

The effects of forskolin on action potential configuration and on both uptake and efflux of 86Rb+ were studied in guinea-pig left atria. The action potential was prolonged by forskolin in the plateau range but shortened at the end of repolarization; maximal upstroke velocity and amplitude of slow response potentials were enhanced. In partially depolarized preparations, the resting potential was increased by forskolin; this effect was not prevented by atropine 1 mumol/l. Forskolin augmented the rate constant of 86Rb+ efflux in beating and in resting preparations. The uptake of 86Rb+ was enhanced by forskolin in resting preparations. It is concluded that forskolin stimulates the Na+,K+-pump and activates a background potassium conductance. Both effects may account for the shortening effect of the drug on the action potential and the increase in resting potential seen in partially depolarized preparations.

Stage specific kinetoplast DNA-binding proteins in Trypanosoma cruzi.

Knowledge regarding kinetoplast DNA organization in all members of the Trypanosomatid family is incomplete. Recently, the presence of kinetoplast-associated proteins in condensing kDNA networks in Crithidia fasciculata has been described and a role for these proteins in the maintenance of these complex structures was suggested. To investigate the presence of protein components in Trypanosoma cruzi kinetoplast, we previously described seven epimastigote kinetoplast-associated proteins. We report here the existence of kinetoplast binding proteins in amastigote and trypomastigote stages of T. cruzi, which could bind both mini and maxicircles components with a stage specific elements for every infective form of the parasite. We propose three major classes of kinetoplast-associated proteins related to the basic processes of this intricate disc structure and suggest a possible function of these binding proteins in the T. cruzi mitochondrial DNA organization.

Entamoeba histolytica collagen binding proteins.

Three main collagen binding proteins from trophozoites of E. histolytica have been isolated: 105 kDa, 56 kDa and 30 kDa. They display a type I collagenolytic activity. The enzyme behaves as a mammalian collagenase regarding to its activity, collagen degradation products and inhibitors. Antibodies against affinity-purified molecules inhibit the binding of trophozoites to collagen substrates. Indirect evidence suggests that the 30 kDa molecule is the putative collagen receptor. These surface molecules may be necessary for attachment and migration of the parasite into solid tissue.

Growth inhibition of Entamoeba histolytica by rat colon components.

Susceptibility to invasive amebiasis has been suggested to be due to intrinsic amebic factors and/or to such host factors as intestinal microflora, mucus and colonic redox potential. We investigated the effect of rat colon components on the growth of axenically cultured E. histolytica trophozoites. Extracts of rat colon tissue produced a 57% amebic growth inhibition. The main growth inhibitory components were precipitated by 65% ammonium sulfate and were heat-sensitive. These components were partially separated by ultrafiltration and gel filtration chromatography. Thus, we found colonic components (Mr 50-100 kDa) that produced strong growth inhibition (75%). These results suggest that rat colonic products may play an active role in resistance to amebic infection.

Identification and partial purification of an Entamoeba histolytica membrane protein that binds fibronectin.

A 37 kDa protein has been described as a putative receptor for fibronectin (Fn) on E. histolytica trophozoites (1). We have now identified a membrane protein that binds biotinylated fibronectin (BFn) with an apparent molecular weight of 140 kDa. Using BFn we were able to follow this protein during partial purification through DEAE-cellulose and Fn-Sepharose chromatography. Antisera prepared against a peptide corresponding to the deduced amino acid sequence for the putative receptor binding site for human Fn (2) recognized a protein with the same molecular weight. The purified protein was also recognized by this sera. We propose that this protein may function as a Fn receptor and will explore the possibility for it being an integrin.

Purification and partial characterization of an hemolytic activity from Entamoeba histolytica.

It is generally accepted that hydrolytic and cytolytic amebic components are involved in the pathogenic mechanisms of E. histolytica. We have now identified a lytic activity in two membrane proteins of 23.5 kDa and 25 kDa, which are able to lyse rat erythrocytes. The activity was purified from total homogenates of the virulent strains HM1:IMSS and HM38:IMSS, and the erythrocyte lysis was directly related to protein concentration. The hemolytic activity was heat-sensitive and resistant to reduction by 2-mercaptoethanol. Total amino acid analysis of pure proteins showed a high hydrophobic amino acid content: 36% for 23.5 kDa and 50% for 25 kDa. This hemolytic activity could be related, along with other amebic factors, to tissue damage.

American trypanosomiasis (Chagas' disease) and blood banking in Mexico City: seroprevalence and its potential transfusional transmission risk.

BACKGROUND: American trypanosomiasis (Chagas' disease), an anthropozoonosis fairly common in rural Latin America, has become an urban disease due to continuous migration, intra- and internationally. Blood transfusion, the second important pathway for transmission, increases its impact. Recognition of seropositive subjects among blood donors is now recommended, and clinical and serological screening enforced. Maneuvers to inactivate or remove Trypanosoma cruzi present in collected blood are recommended. METHODS: We surveyed voluntary donors at the National Institute of Cardiology in Mexico City in search of anti-T. cruzi by indirect immunofluorescence, ELISA, and Western blot analysis. Seropositive donors were identified and tested for immunoglobulin. We used types and fractions of donated blood to extract DNA and perform the PCR technique using kinetoplast primers seeking parasite DNA in blood. RESULTS: After 3,300 donors were screened, we identified 10 seropositive subjects (0.3%). These subjects were considered as indeterminate chagasic patients, came mainly from rural areas, and had IgG (100%) and IgA (30%) antibodies against a crude extract as well as a recombinant T. cruzi antigen. Identification of parasite DNA in red cell and platelet fraction was achieved from eight blood units. CONCLUSIONS: The present data provide evidence that blood donors at an urban hospital are seropositive for T. cruzi and at least 50% of donors carry the parasite potentially able to transmit T. cruzi in their cellular blood products. Serological screening should be included in routine blood-making. It is also necessary to adopt measures to inactivate or eliminate organisms in donated blood.

Modification of the inotropic effect of digoxin by diazepam in rat left atria.

There is a pharmacokinetic interaction between digoxin and diazepam that increases the elimination half-life of digoxin. It may be due to a reduction of digoxin tissue concentrations and to an enhanced effect of diazepam on digoxin binding to plasma albumin. Diazepam (10(-5) M) also induces a positive inotropic effect in guinea-pig isolated atria. In a study of a possible pharmacodynamic interaction between both drugs, the inotropic response to digoxin has been examined in rat isolated atria in the presence of diazepam. The atria were kept in Tyrode at 37 degrees C, bubbled with 95% O2 and 5% CO2 and electrically stimulated at twice the threshold voltage. The results indicate that diazepam induces an inotropic effect at 10(-5) M (P less than 0.05) and reduces (P less than 0.05) at 10(-9), 10(-7) and 10(-5) M the inotropic response to digoxin (10(-5) M).

Interferon- or interleukin-10 production is induced by related Trypanosoma cruzi antigens.

The purpose of this study was to evaluate the effects of a crude Trypanosoma cruzi antigen (TCA) and its partially purified subfractions TCF1, TCF2 on peripheral blood mononuclear cells (PBMC) of normal donors and chagasic patients. TCFI and TCF2 stimulated cells from normal donors and chagasic patients in association with a significant production of interleukin (IL)-10. Only PBMC from chagasic patients multiplied after incubation with TCA and released mainly interferon-y but also IL-10. Neither the production of IL-2 and IL-4 nor CD4/CD8 ratios were changed after culture with antigens. These data suggest that some antigens active during the acute phase of T. cruzi infection would stimulate the production of cytokines that promote progression of infection, and the immune system can produce a desired cytokine(s) once the appropriate antigenic stimulus is used.

[Prostatic angiosarcoma: report of a new case]. / Angiosarcoma prostático: aportación de un nuevo caso.

We report the case of a 31 year old male, with lower urinary tract symptoms. We achieved the diagnosis of an prostate angiosarcoma. The treatment was a retropubic radical prostatectomy and partially resection of bladder neck, followed by chemotherapy with Ifosfamide and Adriamycin. At least 36 months up to surgery the patient is alive and free of symptoms and radiological signs of recurrence.

[Appendix mucinous cystadenoma]. / Cistoadenoma mucinoso apendicular.

Mucous cystadenomas are benign epithelial tumours with great mucous content inside. Despite being non-malignant, they acquired great size, compressing and displacing important structures and organs of the zone, with theirs unlucky outcomes. Surgical exeresis is very difficult, being almost impossible its total exeresis, showing great frequency of relapse. We present an appendix mucous cystadenoma case in a 54 years old patient.

[Melanoma metastatic to the female urethra. Report of a case]. / Melanoma metastásico a uretra femenina. Aportación de un caso.

We report a case of a 77 years old woman with an previous malignant melanoma, who presented an urethral metastasis. The disease was treated with conservative therapy by local excision after pedicle ligation, and she is free of symptoms after one 1 year of control.

[Rare origin of a retroperitoneal mass: Castleman's disease]. / Raro origen de masa retroperitoneal: enfermedad de Castleman.

Castleman's disease (angiofollicular hyperplasia of the lymphatic nodes) can exceptionally appear as a retroperitoneal mass of difficult differential diagnosis relative to other malignant retroperitoneal masses. Because of its rarity, one case report of a retroperitoneal mass with histologic study corresponding to Castleman's disease is contributed. A revision of the different histologic varieties of Castleman's disease, specific treatment and prognosis is included.