RESUMO
Giardia infections in domestic cattle has come under increasing scrutiny owing to the potential contamination of surface and ground waters through manure distribution on fields and pasture runoff. The objective of the study was to determine the prevalence and genotypes of Giardia duodenalis in beef calves in major beef cow calf farms in Alberta, Canada. Fecal samples were collected from beef calves aged 2-10 weeks at nine farms in Alberta. Samples were examined for the presence of G. duodenalis cysts by immunofluorescent staining. Giardia cysts were found in 168 of the 495 fecal samples examined, with prevalence ranging from 7 to 60% among farms. Genotypic analysis of positive isolates utilizing PCR and sequencing of a 292 bp fragment of the 16S-rRNA locus, revealed the hoofed livestock genotype in 41 of the 42 isolates. One isolate was identical to the Assemblage A genotype. The results of this study demonstrate that beef calves in this area are primarily infected with the livestock genotype which is thought to be specific to artiodactyl hosts and non-infective to humans. This suggests that the Giardia carried by beef cattle may be a minimal zoonotic threat.
Assuntos
Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/parasitologia , Giardia/genética , Giardia/isolamento & purificação , Giardíase/epidemiologia , Giardíase/veterinária , Alberta , Animais , Bovinos , Genes de Protozoários/genética , Genótipo , Giardia/classificação , Giardíase/parasitologia , Filogenia , Prevalência , RNA Ribossômico 16S/genéticaRESUMO
The environmental distribution of Giardia spp. and Cryptosporidium spp. is dependent upon human, agricultural, and wildlife sources. The significance of each source with regard to the presence of parasites in the environment is unknown. This 2-year study examined parasite prevalence in human sewage influent, wildlife, and agricultural sources associated with the North Saskatchewan River Basin in Alberta, Canada. Fecal samples were collected from cow-calf, dairy, and hog operations in the watershed area. Sewage-treatment facilities were sampled bimonthly during the 2-year study, and wildlife scat was collected at locations along tributaries of the North Saskatchewan River. All samples were analyzed for the presence of Giardia and Cryptosporidium, using sucrose-gradient separation followed by immunofluorescent microscopy. Giardia and Cryptosporidium were detected in all three sources. The lowest prevalence of both Giardia (3.28%) and Cryptosporidium (0.94%) was found in wildlife, with 6 of 19 species testing positive. Sewage influent had the highest prevalence of Giardia (48.80%) and Cryptosporidium parvum-like oocysts (5.42%); however, the concentration of both parasites was minimal compared with the concentration detected in cattle feces. Cow-calf sources contained the highest concentration of Giardia (mean 5800/g feces, P < 0.01), and dairy sources contained the highest concentration of C. parvum-like oocysts (mean 295/g feces, P < 0.01). Although prevalence and concentration are higher in cattle feces than in sewage, the Giardia and Cryptosporidium in animal manure do not have direct access to water draining into the North Saskatchewan River. PCR-based characterization of rDNA from isolates of Cryptosporidium collected from Alberta human, pig, calf, mature steer, dog, cat, and beaver hosts revealed distinct genetic differences that may reflect host specificity.
Assuntos
Criptosporidiose/veterinária , Cryptosporidium/isolamento & purificação , Giardíase/veterinária , Abastecimento de Água , Água/parasitologia , Animais , Canadá/epidemiologia , Bovinos , Criptosporidiose/epidemiologia , Cryptosporidium/genética , Eletroforese em Gel de Poliacrilamida , Monitoramento Ambiental , Monitoramento Epidemiológico , Fezes/parasitologia , Giardia/genética , Giardia/isolamento & purificação , Giardíase/epidemiologia , Humanos , Reação em Cadeia da Polimerase , PrevalênciaRESUMO
The carcinoid tumor is an uncommon neuroendocrine neoplasm the hallmark of which is excessive serotonin production. In studying kinetics of tryptophan hydroxylase and aromatic-L-amino acid decarboxylase (AAAD) in human carcinoid hepatic metastases and adjacent normal liver (J. A. Gilbert et al, Biochem. Pharmacol., 50: 845-850, 1995), we identified one significant difference: the Vmax of carcinoid AAAD was 50-fold higher than that in normal liver. Here, we report Western and Northern analyses detecting large quantities of AAAD polypeptide and mRNA in human carcinoid primary as well as metastatic tumors compared with normal surrounding tissues. To assess the feasibility of targeting these high AAAD levels for chemotherapy, AAAD inhibitors carbidopa (alpha-methyl-dopahydrazine), alpha-monofluoromethyldopa (MFMD), and 3-hydroxybenzylhydrazine (NSD-1015) were incubated (72 h) with NCI-H727 human lung carcinoid cells. Carbidopa and MFMD were lethal (IC50 = 29 +/- 2 microM and 56 +/- 6 microM, respectively); NSD-1015 had no effect on proliferation. On exposure to other human tumor lines, carbidopa was lethal only to NCI-H146 and NCI-H209 small cell lung carcinoma (SCLC) lines (IC50 = 12 +/- 1 microM and 22 +/- 5 microM, respectively). Carbidopa (100 microM) decreased growth of (but did not kill) SK-N-SH neuroblastoma and A204 rhabdomyosarcoma cells and did not affect proliferation of DU 145 prostate, MCF7 breast, or NCI-H460 large cell lung carcinoma lines. The rank order of lines by AAAD activity was NCI-H146 > NCI-H209 > SK-N-SH > NCI-H727, whereas A204, DU 145, MCF7, and NCI-H460 had no measurable activity. For lung tumor lines (carcinoid, two SCLC, and one large cell lung carcinoma), AAAD activity was correlated with the potency of carbidopa-induced cytotoxicity. However, carcinoid cell death was not solely attributable to complete inhibition of either AAAD activity or the serotonin synthetic pathway. In further evaluating potential applications of these findings with carbidopa, we determined that sublethal doses of carbidopa produced additive cytotoxic effects in carcinoid cells in combination with etoposide and cytotoxic synergy in SCLC cells when coincubated with topotecan.
Assuntos
Inibidores das Descarboxilases de Aminoácidos Aromáticos , Carbidopa/farmacologia , Tumor Carcinoide/tratamento farmacológico , Carcinoma de Células Pequenas/tratamento farmacológico , Inibidores Enzimáticos/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Tumor Carcinoide/enzimologia , Tumor Carcinoide/patologia , Carcinoma de Células Pequenas/enzimologia , Carcinoma de Células Pequenas/patologia , Divisão Celular/efeitos dos fármacos , Humanos , Íleo/enzimologia , Fígado/enzimologia , Neoplasias Pulmonares/enzimologia , Neoplasias Pulmonares/patologia , Microscopia Eletrônica , Células Tumorais CultivadasRESUMO
Health professionals have a high probability of working with populations experiencing death and other types of loss. Surveys of medical, nursing, pharmacy, dental, and social work schools in the United States to determine their offerings in thanatology revealed that the majority (with the exception of dentistry) offer some education on death and dying. Because most of the offerings are limited to one or two lectures, a high percentage of students are graduating with limited formal exposure in this area. However, offerings have come a long way since the early 1970s.