Distributed representation of objects in the human ventral visual pathway.
(25/1829)
Brain imaging and electrophysiological recording studies in humans have reported discrete cortical regions in posterior ventral temporal cortex that respond preferentially to faces, buildings, and letters. These findings suggest a category-specific anatomically segregated modular organization of the object vision pathway. Here we present data from a functional MRI study in which we found three distinct regions of ventral temporal cortex that responded preferentially to faces and two categories of other objects, namely houses and chairs, and had a highly consistent topological arrangement. Although the data could be interpreted as evidence for separate modules, we found that each category also evoked significant responses in the regions that responded maximally to other stimuli. Moreover, each category was associated with its own differential pattern of response across ventral temporal cortex. These results indicate that the representation of an object is not restricted to a region that responds maximally to that object, but rather is distributed across a broader expanse of cortex. We propose that the functional architecture of the ventral visual pathway is not a mosaic of category-specific modules but instead is a continuous representation of information about object form that has a highly consistent and orderly topological arrangement. (+info)
Chagas disease in an area of recent occupation in Cochabamba, Bolivia.
(26/1829)
INTRODUCTION: A descriptive, entomological and seroepidemiological study on Chagas disease was conducted in a place of recent occupation on the outskirts of Cochabamba, Bolivia: Avaroa/Primer de Mayo (population:3,000), where the socio-economic level is low and no control measures have been made available. METHODS: The immunofluorescent antibody test (IFAT) was used for IgG and IgM anti-Trypanosoma cruzi antibodies in filter paper bloodspot eluates from 128 subjects (73 females, 55 males) selected by systematic sampling. Concerning each subject age, gender, birthplace, occupation, duration of residence and building materials used in their houses were recorded. Vectors were captured both in domestic and peridomestic environments. RESULTS: Seropositive, 12.5% (16/128): females, 15.1% (11/73); males, 9.1% (5/55). Average time of residence: 6.1 years for the whole population sample and 7.4 years for the seropositive subjects. Most houses had adobe walls (76. 7%, n= 30), galvanized iron rooves (86.7%) and earthen floors (53. 4%) 80% of the walls had crevices. One hundred forty seven specimens of Triatoma infestans were captured, of which 104 (70.7%) were domestic, and 1 peridomestic Triatoma sordida. Precipitin host identification: birds, 67.5%; humans, 27.8%; rodents, 11.9%; dogs, 8. 7%; cats, 1.6%. House infestation and density indices were 53.3 and 493.0 respectively. We found 21 (14.3%) specimens of T. infestans infected with trypanosomes, 18 (85.7%) of which in domestic environments. DISCUSSION: The elements for the vector transmission of Chagas disease are present in Avaroa/Primer de Mayo and the ancient custom of keeping guinea pigs indoors adds to the risk of human infection. In neighboring Cochabamba, due to substandard quality control, contaminated blood transfusions are not infrequent, which further aggravates the spread of Chagas disease. Prompt action to check the transmission of this infection, involving additionally the congenital and transfusional modes of acquisition, is required. (+info)
Biomass cooking fuels and prevalence of tuberculosis in India.
(27/1829)
OBJECTIVES: To examine the relation between use of biomass cooking fuels (wood or dung) and prevalence of active tuberculosis in India. METHODS: The analysis is based on 260,162 persons age 20 and over in India's 1992-93 National Family Health Survey. Logistic regression is used to estimate the effects of biomass fuel use on prevalence of active tuberculosis, as reported by household heads, after controlling for a number of potentially confounding variables. RESULTS: Persons living in households that primarily use biomass for cooking fuel have substantially higher prevalence of active tuberculosis than persons living in households that use cleaner fuels (odds ratio [OR] = 3.56; 95% confidence interval [CI] = 2.82-4. 50). This effect is reduced somewhat when availability of a separate kitchen, house type, indoor crowding, age, gender, urban or rural residence, education, religion, caste or tribe, and geographic region are statistically controlled (OR = 2.58; 95% CI = 1.98-3.37). Fuel type also has a large effect when the analysis is done separately for men (OR = 2.46; 95% CI = 1.79-3.39) and women (OR = 2. 74; 95% CI = 1.86-4.05) and separately for urban areas (OR = 2.29; 95% CI = 1.61-3.23) and rural areas (OR = 2.65; 95% CI = 1.74-4.03). The analysis also indicates that, among persons age 20 years and over, 51% of the prevalence of active tuberculosis is attributable to cooking smoke. CONCLUSIONS: Results strongly suggest that use of biomass fuels for cooking substantially increases the risk of tuberculosis in India. (+info)
Decreased point prevalence of Haemophilus influenzae type b (Hib) oropharyngeal colonization by mass immunization of Brazilian children less than 5 years old with hib polyribosylribitol phosphate polysaccharide-tetanus toxoid conjugate vaccine in combination with diphtheria-tetanus toxoids-pertussis vaccine.
(28/1829)
A protective herd effect has been described after susceptible populations of children are vaccinated with conjugate Haemophilus influenzae type b (Hib). Hib carriage was studied in children aged 6-24 months attending day care centers in two cities in southern Brazil (Curitiba and Porto Alegre). In Curitiba, routine immunization with Hib polyribosylribitol phosphate polysaccharide-tetanus toxoid conjugate vaccine (PRP-T) in combination with diphtheria-tetanus toxoids-pertussis vaccine (PRP-T/DTP) has been offered since September 1996; DTP vaccine alone is routinely given in Porto Alegre. Children in Porto Alegre (n=643) were 8 times less likely to have received adequate Hib vaccination and 4 times more likely to be Hib carriers than children in Curitiba (n=647; i.e., point prevalence of oropharyngeal colonization, 4.8% vs. 1.2%). Point prevalence of carriage with non-type b or other nontypeable Hi was similar in children of both cities. There was a vaccination effect on carriage rates in children who received a primary 3-dose series, independent of the booster dose, suggesting that a booster may be unnecessary to induce population protection. (+info)
Radon testing in households with a residential smoker--United States, 1993-1994.
(29/1829)
Epidemiologic investigations of underground miners and studies of alpha particle carcinogenesis among laboratory animals suggest that exposure to the radioactive decay products (progeny) of radon is an important risk factor for lung cancer. Persons who smoke cigarettes and are exposed to these radon progeny have a substantially greater risk for developing malignancy than nonsmokers. Residential radon concentrations above the U.S. Environmental Protection Agency's (EPA) action level of 4 pCi/L are the primary sources of exposure among the general population. EPA and the Public Health Service promote home testing for radon, especially in households with a person who smokes. However, it is unknown whether households that contain smokers are more likely than those without smokers to test for radon. To characterize radon testing practices of households that contain a person who smokes within the dwelling (i.e., residential smoker), CDC analyzed survey data from the National Health Interview Survey (NHIS). This report summarizes the results of this analysis, which indicates that households with a residential smoker are significantly less likely to test for radon than those without smokers. (+info)
Prediction of toxigenic fungal growth in buildings by using a novel modelling system.
(30/1829)
There is growing concern about the adverse effects of fungal bioaerosols on the occupants of damp dwellings. Based on an extensive analysis of previously published data and on experiments carried out within this study, critical limits for the growth of the indoor fungi Eurotium herbariorum, Aspergillus versicolor, and Stachybotrys chartarum were mathematically described in terms of growth limit curves (isopleths) which define the minimum combination of temperature (T) and relative humidity (RH) at which growth will occur. Each growth limit curve was generated from a series of data points on a T-RH plot and mathematically fitted by using a third-order polynomial equation of the form RH = a(3)T(3) + a(2)T(2) + a(1)T + a(0). This fungal growth prediction model was incorporated within the ESP-r (Environmental Systems Performance [r stands for "research"]) computer-based program for transient simulation of the energy and environmental performance of buildings. For any specified location, the ESP-r system is able to predict the time series evolution of local surface temperature and relative humidity, taking explicit account of constructional moisture flow, moisture generation sources, and air movement. This allows the predicted local conditions to be superimposed directly onto fungal growth curves. The concentration of plotted points relative to the curves allows an assessment of the risk of fungal growth. The system's predictive capability was tested via laboratory experiments and by comparison with monitored data from a fungus-contaminated house. (+info)
Infant pulmonary hemorrhage in a suburban home with water damage and mold (Stachybotrys atra).
(31/1829)
The American Academy of Pediatrics recently issued guidelines regarding the potential toxic effect of indoor molds. We now report another case of an infant with pulmonary hemorrhage whose residential environmental assessment revealed the presence of the toxigenic mold Stachybotrys atra. We used a questionnaire to identify environmental factors that could predispose the home to fungal contamination. We collected air samples from multiple locations in the home that we felt would reflect areas of relevant exposure. Surface samples were collected with a piece of transparent tape for semiquantitative measurement of spores present. We classified spores into their respective genera based on shape, size, and color. We also measured mycotoxin levels. Air sampling revealed significantly elevated total spore counts in the patient's bedroom and in the attic. Aspergillus/Penicillium species were predominant. Stachybotrys spores were found in the air sampled in the patient's bedroom, as well as from surfaces sampled in the patient's closet and the attic ceiling. Additionally, a small patch of Stachybotrys-contaminated area in the closet ceiling was sent for mycotoxin analysis. This material proved to be highly toxigenic. As the link between the presence of Stachybotrys in the home and pulmonary hemorrhage in infants increases, further efforts should be made to educate physicians, health care providers, and new parents about the potential toxic effects of this mold. (+info)
Prevalence of Trypanosoma cruzi and Leishmania chagasi infection and risk factors in a Colombian indigenous population.
(32/1829)
This study was carried out in order to obtain base-line data concerning the epidemiology of American Visceral Leishmaniasis and Chagas' Disease in an indigenous population with whom the government is starting a dwelling improvement programme. Information was collected from 242 dwellings (1,440 people), by means of house to house interviews about socio-economic and environmental factors associated with Leishmania chagasi and Trypanosoma cruzi transmission risk. A leishmanin skin test was applied to 385 people and 454 blood samples were collected on filter paper in order to detect L. chagasi antibodies by ELISA and IFAT and T. cruzi antibodies by ELISA. T. cruzi seroprevalence was 8.7% by ELISA, L. chagasi was 4.6% and 5.1% by IFAT and ELISA, respectively. ELISA sensitivity and specificity for L. chagasi antibodies were 57% and 97.5% respectively, as compared to the IFAT. Leishmanin skin test positivity was 19%. L. chagasi infection prevalence, being defined as a positive result in the three-immunodiagnostic tests, was 17.1%. Additionally, 2.7% of the population studied was positive to both L. chagasi and T. cruzi, showing a possible cross-reaction. L. chagasi and T. cruzi seropositivity increased with age, while no association with gender was observed. Age (p<0.007), number of inhabitants (p<0. 05), floor material (p<0.03) and recognition of vector (p<0.01) were associated with T. cruzi infection, whilst age ( p<0.007) and dwelling improvement (p<0.02) were associated with L. chagasi infection. It is necessary to evaluate the long-term impact of the dwelling improvement programme on these parasitic infections in this community. (+info)