RESUMO
The aim of this study was to determine the prevalence, virulence factors (stx, eae, ehxA and astA) and phylogenetic relationships [PFGE and multilocus sequence typing (MLST)] of Shiga toxin-producing Escherichia coli (STEC) strains isolated from four previous cohort studies in 2212 Peruvian children aged <36 months. STEC prevalence was 0.4â% (14/3219) in diarrhoeal and 0.6â% (15/2695) in control samples. None of the infected children developed haemolytic uraemic syndrome (HUS) or other complications of STEC. stx1 was present in 83â% of strains, stx2 in 17â%, eae in 72â%, ehxA in 59â% and astA in 14â%. The most common serotype was O26â:âH11 (14â%) and the most common seropathotype was B (45â%). The strains belonged mainly to phylogenetic group B1 (52â%). The distinct combinations of alleles across the seven MLST loci were used to define 13 sequence types among 19 STEC strains. PFGE typing of 20 STEC strains resulted in 19 pulsed-field patterns. Comparison of the patterns revealed 11 clusters (I-XI), each usually including strains belonging to different serotypes; one exception was cluster VI, which gathered exclusively seven strains of seropathotype B, clonal group enterohaemorrhagic E. coli (EHEC) 2 and phylogenetic group B1. In summary, STEC prevalence was low in Peruvian children with diarrhoea in the community setting. The strains were phylogenetically diverse and associated with mild infections. However, additional studies are needed in children with bloody diarrhoea and HUS.
Assuntos
Infecções por Escherichia coli/microbiologia , Escherichia coli Shiga Toxigênica/classificação , Escherichia coli Shiga Toxigênica/genética , Adesinas Bacterianas/genética , Sequência de Bases , Estudos de Casos e Controles , Pré-Escolar , Estudos de Coortes , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado , Infecções por Escherichia coli/epidemiologia , Proteínas de Escherichia coli/genética , Feminino , Genes Bacterianos , Proteínas Hemolisinas/genética , Humanos , Lactente , Recém-Nascido , Masculino , Tipagem de Sequências Multilocus , Peru/epidemiologia , Filogenia , Prevalência , Sorotipagem , Toxina Shiga/genética , Escherichia coli Shiga Toxigênica/isolamento & purificação , Fatores de Virulência/genéticaRESUMO
Enterotoxigenic Escherichia coli (ETEC) is a major cause of childhood diarrhea. The present study sought to determine the prevalence and distribution of toxin types, colonization factors (CFs), and antimicrobial susceptibility of ETEC strains isolated from Peruvian children. We analyzed ETEC strains isolated from Peruvian children between 2 and 24 months of age in a passive surveillance study. Five E. coli colonies per patient were studied by multiplex real-time PCR to identify ETEC virulence factors. ETEC-associated toxins were confirmed using a GM1-based enzyme-linked immunosorbent assay. Confirmed strains were tested for CFs by dot blot assay using 21 monoclonal antibodies. We analyzed 1,129 samples from children with diarrhea and 744 control children and found ETEC in 5.3% and 4.3%, respectively. ETEC was more frequently isolated from children >12 months of age than from children <12 months of age (P < 0.001). Fifty-two percent of ETEC isolates from children with diarrhea and 72% of isolates from controls were heat-labile enterotoxin (LT) positive and heat-stable enterotoxin (ST) negative; 25% and 19%, respectively, were LT negative and ST positive; and 23% and 9%, respectively, were LT positive and ST positive. CFs were identified in 64% of diarrheal samples and 37% of control samples (P < 0.05). The most common CFs were CS6 (14% and 7%, respectively), CS12 (12% and 4%, respectively), and CS1 (9% and 4%, respectively). ST-producing ETEC strains caused more severe diarrhea than non-ST-producing ETEC strains. The strains were most frequently resistant to ampicillin (71%) and co-trimoxazole (61%). ETEC was thus found to be more prevalent in older infants. LT was the most common toxin type; 64% of strains had an identified CF. These data are relevant in estimating the burden of disease due to ETEC and the potential coverage of children in Peru by investigational vaccines.
Assuntos
Escherichia coli Enterotoxigênica/classificação , Escherichia coli Enterotoxigênica/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Antibacterianos/farmacologia , Anticorpos Antibacterianos , Anticorpos Monoclonais , Toxinas Bacterianas/biossíntese , Toxinas Bacterianas/genética , Estudos de Casos e Controles , Pré-Escolar , Diarreia/microbiologia , Escherichia coli Enterotoxigênica/genética , Escherichia coli Enterotoxigênica/metabolismo , Enterotoxinas/biossíntese , Enterotoxinas/genética , Ensaio de Imunoadsorção Enzimática/métodos , Proteínas de Escherichia coli/biossíntese , Proteínas de Escherichia coli/genética , Feminino , Humanos , Lactente , Masculino , Testes de Sensibilidade Microbiana , Peru , Reação em Cadeia da Polimerase/métodos , Fatores de Virulência/biossíntese , Fatores de Virulência/genéticaRESUMO
OBJECTIVE: To describe geographical patterns of implementation of the Integrated Management of Childhood Illness (IMCI) strategy in three countries and to assess whether the strategy was implemented in areas with the most pressing child health needs. METHODS: We conducted interviews with key informants at the national and district levels in Brazil, Peru and the United Republic of Tanzania, and an ecological study of factors associated with health worker training in IMCI. Explanatory factors included district population, distance from the capital, human development index, other socioeconomic indicators and baseline mortality rates in children younger than five years. FINDINGS: In line with recommendations by WHO, early implementation districts were characterized by proximity to the capital and suitable training sites, presence of motivated health managers and a functioning health system. In the expansion phase, IMCI tended to be adopted by other districts with similar characteristics. In Brazil, uptake by poor and small municipalities and those further away from the state capital was significantly lower. In Peru, there was no association with distance from Lima, and a non-significant trend for IMCI adoption by small and poor departments. In the United Republic of Tanzania, the only statistically significant finding was a lower uptake by remote districts. Implementation was not associated with baseline mortality levels in any country studied. CONCLUSION: Whereas clear and reasonable guidelines are provided for selection of early use districts, no criteria for promoting IMCI expansion had been issued, and areas of greatest need were not prioritized. Equity analyses based on the geographical deployment of new programmes and strategies can contribute to assessing whether they are reaching those who need them most.
Assuntos
Serviços de Saúde da Criança/organização & administração , Prestação Integrada de Cuidados de Saúde , Implementação de Plano de Saúde , Área Carente de Assistência Médica , Pobreza , Brasil/epidemiologia , Criança , Serviços de Saúde da Criança/provisão & distribuição , Pré-Escolar , Difusão de Inovações , Geografia , Pesquisas sobre Atenção à Saúde , Acessibilidade aos Serviços de Saúde , Necessidades e Demandas de Serviços de Saúde , Humanos , Lactente , Recém-Nascido , Entrevistas como Assunto , Peru/epidemiologia , Avaliação de Programas e Projetos de Saúde , Tanzânia/epidemiologiaRESUMO
This study was conducted to establish reference values for percent oxygen saturation of hemoglobin (SaO2, %) and heart rate (HR, bpm) in children living at high altitude (4,100 m) and to relate possible differences in the variables with ethnic origin. Healthy children from a mine-located school (Tintaya, n = 417), a nearby school (Marquiri, n = 474), and a rural Andean community (Nuñoa, n = 373) were investigated. The samples included different ethnic combinations, with the Nuñoa children having a predominant Quechua ancestry. Mean SaO2 for all ages was substantially lower in all high altitude children compared to values considered normal for sea level. Among the three samples, SaO2 was higher (91.3 +/- 2.7) and HR was lower (84.8 +/- 13.6) in Nuñoa than in Tintaya (SaO2, 89.8 +/- 2.5; HR, 91.7 +/- 14.9) and Marquiri (SaO2, 89.6 +/- 3.1; HR, 88.5 +/- 12.9) (P < 0.05). There was no sex difference and only a weak age-dependent trend for SaO2. Values considered abnormal at sea level were observed in all healthy high-altitude children. Higher SaO2 and lower HR in Nuñoa children may suggest a better degree of acclimatization to altitude.
Assuntos
Altitude , Etnicidade/estatística & dados numéricos , Frequência Cardíaca , Oxigênio/sangue , Aclimatação , Adolescente , Distribuição por Idade , Criança , Humanos , Indígenas Sul-Americanos , Modelos Lineares , Análise Multivariada , Peru , Valores de Referência , Distribuição por Sexo , Estatísticas não ParamétricasRESUMO
The growth of children living in two high-altitude communities associated with an active copper mine in southern Peru was examined. In the community directly associated with mining operations, nutritional and health conditions were believed to be relatively favorable as a result of the substantial mine-related infrastructure that had developed over the previous 12 years. In contrast, few such benefits were available in the other community, which provides limited part-time labor at the mine. Anthropometric data, including measurements of height, weight, skinfold thicknesses, upper arm circumference, and chest dimensions, and determination of bone age, were collected from a total of 880 children between the ages of 4 and 18 years. There were significant differences between the two communities, with those in the mining community exhibiting significantly greater height and weight, a higher level of body fat, and more rapid skeletal development. Among children over the age of 12 years, a plateau in height was seen, suggesting that the benefits to growth resulting from mining-related development were more noticeable in younger children. Compared with Peruvian high-altitude populations examined during the 1960s, both samples from the present study were substantially taller and heavier, suggesting that despite local differences in socioeconomic conditions between the communities studied, overall conditions for growth are generally more favorable than those that existed among Peruvian high-altitude populations surveyed in the 1960s.
Assuntos
Altitude , Transtornos da Nutrição Infantil/etiologia , Cobre , Transtornos do Crescimento/etiologia , Mineração/estatística & dados numéricos , Pobreza/estatística & dados numéricos , Adolescente , Antropometria , Estatura , Peso Corporal , Criança , Transtornos da Nutrição Infantil/diagnóstico , Transtornos da Nutrição Infantil/epidemiologia , Proteção da Criança , Pré-Escolar , Fatores de Confusão Epidemiológicos , Feminino , Transtornos do Crescimento/diagnóstico , Transtornos do Crescimento/epidemiologia , Nível de Saúde , Humanos , Análise dos Mínimos Quadrados , Estudos Longitudinais , Masculino , Inquéritos Nutricionais , Estado Nutricional , Peru/epidemiologiaRESUMO
Prevalence of excessive erythrocytosis, the main sign of chronic mountain sickness (CMS), is greater in postmenopausal Andean women than in premenopausal women. It is uncertain whether this greater prevalence is related to the decline in female hormones and ventilatory function after the occurrence of the menopause. To study this, we compared the physiological variables involved in the physiopathology of CMS [end-tidal CO(2) (PET(CO(2)), Torr) and end-tidal O(2) (PET(O(2)), Torr), arterial oxygen saturation (Sa(O(2)), %), and Hb concentration (g/dl)] and progesterone and estradiol levels between postmenopausal and premenopausal women, both in the luteal and follicular phases. Women residing in Cerro de Pasco (n = 33; 4,300 m) aged 26--62 yr were studied. Postmenopausal women compared with premenopausal women in the luteal phase had lower PET(O(2)) (48 +/- 4 vs. 53 +/- 2 Torr, P = 0.005) and Sa(O(2)) levels (82 +/- 12 vs. 88 +/- 12%, P < 0.005) and higher PET(CO(2)) (34 +/- 2 vs. 29 +/- 3 Torr, P = 0.005) and Hb concentration (19 +/- 1 vs. 14 +/- 2 g/dl, P < 0.005). In addition, plasma progesterone was negatively correlated with PET(CO(2)) and positively correlated with PET(O(2)) and Sa(O(2)). No clear relationship was found among the cycle phases between estradiol and the variables studied. In conclusion, our results reveal that, before menopause, there is better oxygenation and lower Hb levels in women long residing at altitude, and this is associated with higher levels of progesterone in the luteal phase of the cycle.
Assuntos
Altitude , Estradiol/sangue , Fase Folicular/fisiologia , Hipóxia , Fase Luteal/fisiologia , Ovário/fisiologia , Pós-Menopausa/fisiologia , Pré-Menopausa/fisiologia , Progesterona/sangue , Adulto , Pressão Sanguínea , Dióxido de Carbono/sangue , Feminino , Frequência Cardíaca , Humanos , Indígenas Sul-Americanos , Pessoa de Meia-Idade , Oxigênio/sangue , PeruRESUMO
This randomized, observer-blind, multicenter, parallel-group study compared the clinical and bacteriologic efficacy and safety of amoxycillin, 45 mg/kg/day b.d. and amoxycillin, 40 mg/kg/day t.d.s. after 7 days of treatment in 517 children with acute bacterial tonsillopharyngitis. At the end of treatment, a successful clinical response was recorded in more than 96% of patients in each of the treatment groups. A similar result was obtained at follow-up. Among those patients who were bacteriologically evaluable at the end of treatment, a successful bacteriologic response was achieved in more than 94% in each treatment group. Both treatments were well tolerated. Drug-related adverse events were recorded in just 12 patients (4.6%) in the b.d. group and six (2.4%) in the t.d.s. group. The study demonstrated that a twice-daily regimen of amoxycillin, 45 mg/kg/day, was as effective and as well tolerated as the standard three-times-daily regimen of amoxycillin, 40 mg/kg/day, in the treatment of acute bacterial tonsillopharyngitis in children.
Assuntos
Amoxicilina/administração & dosagem , Penicilinas/administração & dosagem , Faringite/tratamento farmacológico , Infecções Estreptocócicas/tratamento farmacológico , Streptococcus pyogenes , Tonsila Faríngea , Amoxicilina/uso terapêutico , Criança , Pré-Escolar , Feminino , Hemólise , Humanos , Masculino , Penicilinas/uso terapêutico , Faringite/microbiologia , Método Simples-Cego , Streptococcus pyogenes/efeitos dos fármacosRESUMO
Neste estudo observador-cego, cento e setenta e um pacientes com evidência clínica de faringotonsilite foram randomizados para serem submetidos ao tratamento com amoxicilina administrada duas vezes ao dia(bd)ou três vezes ao dia (tid). Este é um relatório descritivo preliminar, até o momento, a característica "observador-cego" do estudo. Assim, os grupos de pacientes estäo sendo caracterizados como "Tratamento A" e "Tratamento B". Ao final do tratamento, foi obtido um índice de cura clínica de noventa e seis e cinco por cento para os pacientes do grupo "Tratamento A" e noventa e seis e cinco por cento para pacientes do grupo "Tratamento B", sugerindo equivalência terapêutica entre os grupos quanto à eficácia clínica. Os dois esquemas posológicos foram bem tolerados. Em conclusäo, os dados apresentados sugerem que o regime terapêutico de amoxilina administrada duas vezes ao dia (bd) seja täo eficaz quanto o regime de amoxicilina administrada três vezes ao dia (tid) para o tratamento destes pacientes, com a vantagem de poder determinar maior aderência dos doentes ao tratamento
Assuntos
Amoxicilina/administração & dosagem , Amoxicilina/uso terapêutico , Faringite/tratamento farmacológico , Tonsilite/tratamento farmacológicoRESUMO
OBJECTIVE: To compare fecal screening tests in the diagnostic approach to childhood invasive diarrhea. SETTING AND PATIENTS: We assessed 125 consecutive children with acute diarrhea for fecal lactoferrin, fecal leukocytes and occult blood from November, 1995, to June, 1996. RESULTS: Lactoferrin showed a greater overall sensitivity than fecal leukocytes or occult blood for detecting invasive pathogens. Combinations of lactoferrin or fecal leukocytes and of lactoferrin or occult blood or both yielded sensitivities and negative predictive values close to 100%, being superior to all other combinations. All patients with full breast-feeding and mixed feeding had a positive lactoferrin test with a 1:50 dilution used as the cutoff. In controls without diarrhea being exclusively bottle-fed, 3 of 15 (20%) still showed a positive lactoferrin result at the dilution of 1:50. This compared with 15 of 15 (100%) positive results among controls fully breast-fed, 14 of 15 (93%) among controls predominantly breast-fed and 11 of 15 (73%) among control children predominantly bottle-fed. CONCLUSIONS: This study confirms the usefulness of lactoferrin testing as a negative predictor. Breast-feeding lowers the specificity of the test but does not alter the sensitivity. Fecal lactoferrin may be viewed as the screening test of choice to avoid expensive stool cultures in the diagnostic approach to invasive diarrhea.
Assuntos
Diarreia/diagnóstico , Fezes/química , Lactoferrina/análise , Leucócitos , Sangue Oculto , Criança , Fezes/citologia , Humanos , Estudos Prospectivos , Sensibilidade e EspecificidadeRESUMO
A novel modified India ink technique for the diagnosis of Cryptococcus neoformans in cerebrospinal fluid specimens is described. It employs 2% chromium mercury and India ink. This technique allows a clear identification of some external and internal structures of the organism. Three layers from the outer capsule that have previously been discerned only by electron microscopy are distinguished.
Assuntos
Carbono , Criptococose/líquido cefalorraquidiano , Cryptococcus neoformans/isolamento & purificação , Corantes , HumanosRESUMO
OBJECTIVE: To evaluate the value of fecal leukocytes, fecal occult blood, fecal lactoferrin and combination of fecal leukocytes with clinical data in the workup of patients with inflammatory diarrhea. DATA IDENTIFICATION: A systematic literature search in all languages using MEDLINE (1970 to 1994), reference lists of articles primarily retrieved and of review articles and correspondence with experts in the field. STUDY SELECTION: The search identified 2603 references, 81 of which were deemed relevant on the basis of prespecified selection criteria. Of these 25 contained sufficient data for further analysis and thus were finally included. DATA EXTRACTION: All data from the selected articles were extracted by one observer whereas the second reviewer checked these data for accuracy. True positive rates and false positive rates were calculated from each 2 x 2 table. RESULTS OF DATA ANALYSIS: The study summarizes the diagnostic accuracy of the signaled tests as predictors of inflammatory diarrhea as defined by stool culture (the reference test). Plots of true positive rates against false positive rates demonstrated widely scattered points, indicating heterogeneity. A summary receiver operating characteristic curve was fitted to the data with the use of logistic transforms and weighted least squares linear regression. Of the 25 studies analyzed 38 data points were used to construct summary receiver operating characteristic curves for index tests. CONCLUSIONS: Fecal lactoferrin was the most accurate index test. Fecal leukocytes showed the lowest performance as assessed by the area under the curve. Occult blood and combination of fecal leukocytes with clinical data yielded intermediate curves. A limited number of studies (fecal lactoferrin, and fecal leukocytes with clinical data) and methodologic flaws identified in the assessed studies must be solved in future primary studies to improve the usefulness of the metaanalytic approach used here.
Assuntos
Doenças Transmissíveis/diagnóstico , Doenças Transmissíveis/etiologia , Diarreia/diagnóstico , Diarreia/etiologia , Fezes/química , Fezes/citologia , Sangue , Reações Falso-Negativas , Reações Falso-Positivas , Humanos , Inflamação/diagnóstico , Lactoferrina/análise , LeucócitosRESUMO
Sodium cyanate (NaOCN) first appeared on the biomedical scene as a potential therapeutic agent for sickle-cell disease. Although it did not fulfill its early promise in the clinic, it proved to be useful as a pharmacological tool in physiological research, particularly in the physiology of oxygen transport. NaOCN has been especially valuable in the area of investigation which is reviewed here: the study of oxygen transport, both in normoxic and in hypoxic conditions, in experimental models in which NaOCN was used to induce a shift to the left of the oxygen dissociation curve. The classical idea is that a low Hb-O2 affinity is of adaptive value for life at high altitudes but it has been challenged by several pieces of evidence. One of them is the demonstration of increased survival in hypoxic hypoxia of animals with a high Hb-O2 affinity induced by NaOCN. We also discuss the advantages and potentially confounding factors which should be taken into consideration when interpreting results of studies in which the oxygen dissociation curve has been modified by administration of NaOCN.
Assuntos
Altitude , Anemia Falciforme/tratamento farmacológico , Cianatos/metabolismo , Cianatos/uso terapêutico , Desenvolvimento Embrionário e Fetal/efeitos dos fármacos , Eritropoese/efeitos dos fármacos , Hemoglobinas/metabolismo , Hipóxia/tratamento farmacológico , Ventilação Pulmonar/fisiologia , Animais , HumanosRESUMO
Sodium cyanate (NaOCN) first appeared on the biomedical scene as a potential therapeutic agent for sickle-cell disease. Although it did not fulfill its early promise in the clinic, it proved to be useful as a pharmacological tool in physiological research, particularly in the physiology of oxygen transport. NaOCN has been especially valuable in the area of investigation which is reviewed here: the study of oxygen transport, both in normoxic and in hypoxic conditions, in experimental models in which NaOCN was used to induce a shift to the left of the oxygen dissociation curve. The classical idea is that a low Hb-O2 affinity is of adaptive value for life at high altitudes but it has been challenged by several pieces of evidence. One of them is the demonstration of increased survival in hypoxic hypoxia of animals with a high Hb-O2 affinity induced by NaOCN. We also discuss the advantages and potentially confounding factors which should be taken into consideration when interpreting results of studies in which the oxygen dissociation curve has been modified by administration of NaOCN
Assuntos
Animais , Humanos , Altitude , Anemia Falciforme/tratamento farmacológico , Cianatos/metabolismo , Cianatos/uso terapêutico , Eritropoese/efeitos dos fármacos , Desenvolvimento Fetal/efeitos dos fármacos , Hemoglobinas/metabolismo , Hipóxia/tratamento farmacológico , Ventilação Pulmonar/fisiologiaRESUMO
Acid-fast, coccidian-like bodies (Cyclospora cayetanensis) were identified over the last 18 months in the stools of seven Peruvian patients suffering from diarrhoea. The follow-up of two patients revealed a watery, self-limited diarrhoea, which lasted for up to four weeks. The organism was simultaneously identified in the diarrhoeal stools of three members of the same family who drank unchlorinated canal water and in the stools of a duck bred by this family. The organism was not found in the faecal samples of 50 healthy subjects and 10 ducks bred by families without known diarrhoea cases. These findings, albeit preliminary, may be suggesting that besides consumption of untreated water, additional modes of transmission such as contact with domestic animals may be important in this disease. Further studies are needed to assess whether this disease behaves as a zoonotic condition and to ascertain the relative importance of symptom-free subjects in person-to-person transmission of the organism.
Assuntos
Coccidiose/parasitologia , Diarreia/parasitologia , Eucoccidiida/isolamento & purificação , Fezes/parasitologia , Enteropatias Parasitárias/parasitologia , Adolescente , Adulto , Animais , Criança , Coccidiose/transmissão , Patos/parasitologia , Feminino , Humanos , Enteropatias Parasitárias/transmissão , Masculino , Peru , Abastecimento de ÁguaRESUMO
During the recent cholera epidemic which affected Peru and other Latin American countries, fresh stool samples of 100 hospitalized children were assessed February through April 1991. The children had been admitted because of profuse watery diarrhea. The microbiologic study of wet mount preparations showed curved bacteria suspicious for cholera agent and confirmed afterward to be Vibrio cholerae 01 scrotype Inaba. In 30% of such cases, besides the curved bacteria, a strikingly large number of trophozoites of Giardia intestinalis were observed. The same samples studied by permanent stains confirmed the presence of Giardia trophozoites. To our knowledge, the association of Giardia with serious epidemic cholera infection has not been previously described. All patients were admitted because of severe dehydration requiring intravenous fluid replacement, which might suggest a synergistic role for the above-noted coinfection. Adequately designed case-control studies are needed to ascertain the frequency and the pathophysiologic and clinical significance of such an unusual association.
Assuntos
Cólera/epidemiologia , Diarreia/epidemiologia , Diarreia/microbiologia , Giardia lamblia/isolamento & purificação , Giardíase/epidemiologia , Vibrio cholerae/isolamento & purificação , Animais , Criança , Comorbidade , Hospitalização , Humanos , Incidência , Peru/epidemiologiaRESUMO
A prospective study of 111 young Peruvian children with Campylobacter jejuni diarrhoea showed that it behaves as an endemic enterotoxigenic-like, waterborne, milkborne, and zoonotic disease. Although there were no definite differential features between pure C. jejuni diarrhoea, mixed-agent diarrhoea, and C. jejuni diarrhoea plus parenteral infections, children with C. jejuni diarrhoea plus parenteral infections were all inpatients, were more frequently malnourished and more frequently exhibited systemic symptoms. Campylobacter jejuni associated with other enteric pathogens did not seem to act synergistically as the disease was not particularly severe in this group.
Assuntos
Infecções por Campylobacter/epidemiologia , Campylobacter jejuni , Diarreia Infantil/epidemiologia , Infecções por Campylobacter/microbiologia , Pré-Escolar , Diarreia Infantil/complicações , Diarreia Infantil/microbiologia , Humanos , Lactente , Estado Nutricional , Peru/epidemiologia , Estudos ProspectivosRESUMO
The Hb-O2 affinity and the erythropoietic response as a function of time were studied in mice treated with sodium cyanate for up to 2 months. Cyanate increased the Hb-O2 affinity in normoxic mice more than in chronically hypoxic mice. The hemoglobin concentration rose as a function of time both in normoxic and hypoxic conditions but reached higher levels in hypoxia. After 42 days of study (21 days of hypoxia) hemoglobin reached maximum levels and thereafter showed a plateau in both cyanate and control animals. It is concluded that a chronic left-shifted oxygen dissociation curve does not avoid the development of hypoxic polycythemia in mice. Moreover, prolonged cyanate administration potentiates the erythropoietic response to chronic hypoxia. Since polycythemia is an index of tissue hypoxia, the results show that the high hemoglobin affinity did not prevent tissue hypoxia in low PO2 conditions. Results showing beneficial effects of high hemoglobin oxygen affinity induced by cyanate based on acute hypoxic expositions should be cautiously interpreted with regard to their adaptive value in animals chronically exposed to natural or simulated hypoxia.
Assuntos
Hipóxia Celular/fisiologia , Cianatos/administração & dosagem , Hemoglobinas/metabolismo , Oxigênio/sangue , Altitude , Animais , Masculino , Camundongos , Policitemia/etiologia , Fatores de TempoRESUMO
A study performed on Peruvian children < 10 years of age and their controls showed that Campylobacter jejuni is a leading cause of diarrhoea. Infants 1 year old or younger were the most affected. The disease was usually moderately severe, although > 50 per cent of patients required i.v. fluid therapy. Campylobacter was also more frequent in malnourished patients, who come from socio-economically deprived groups, with overcrowding, poor sanitation, and frequent contact with domestic birds and animals. The seasonal behaviour suggests that diarrhoea caused by Campylobacter is endemic in this area.