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At least 343 records · Page 19Linked to original sources
PubMed2006

The mahogany family "out-of-Africa": divergence time estimation, global biogeographic patterns inferred from plastid rbcL DNA sequences, extant, and fossil distribution of diversity.

With information on fossils and extant distribution of diversity/endemism in the mahogany family, we perform a global biogeographic study of Meliaceae using plastid rbcL data for all subfamilies, tribes and nearly all genera. Our study indicates that: (1) Meliaceae are of western Gondwanan origin; (2) dispersal played an important role for the current distribution of mahogany biota; and (3) the direction of dispersal was most likely an "out-of-Africa" scenario with important dispersal routes across Eurasia and between Eurasia and North America provided by Beringia and the North Atlantic land bridge and North America and South America via island chains and/or direct land connections. Populations in North America, Europe, and East Asia were presumably eliminated as tropical climates disappeared from these areas during the Miocene. Extensive Meliaceae fossil findings confirm that the entry of megathermal (frost-intolerant) angiosperms into southern continents from Oligocene to Pliocene must be considered as an important means of establishing pantropical distribution patterns.

Africa↗
PubMed2001

The prevalence and risk factors for pterygium in an adult Chinese population in Singapore: the Tanjong Pagar survey.

PURPOSE: To determine the prevalence and risk factors for pterygium in the Chinese population of Singapore. METHODS: A population-based survey was conducted in Singapore, an island located 1 degree north of the equator with a stable tropical climate. A disproportionate, stratified, clustered, random sampling procedure was used to select the names of 2000 Chinese people aged 40 to 79 years from the 1996 electoral register in the Tanjong Pagar district of Singapore. Selected subjects underwent a comprehensive interview and ocular examination. Pterygium was diagnosed and graded clinically as grade 1 (transparent), 2 (intermediate), and 3 (opaque). Risks factors associated with pterygium and grade 3 pterygium were evaluated with logistic regression models. RESULTS: From a total of 1717 eligible subjects, 1232 (71.8%) were examined. There were 120 people with either unilateral (n = 70) or bilateral (n = 50) pterygium, equivalent to an overall prevalence of 6.9% (95% confidence interval [CI], 5.2, 8.8) in the Chinese population aged 40 and older. The prevalence increased linearly with age (chi-square test of trend P <.001) and was higher among men than women (age-adjusted odds ratio [OR], 4.2; 95% CI, 2.5, 6.9). Men aged 70 and above had the highest overall prevalence of 25.4% (95% CI, 18.2, 19.4), but pterygium was not seen in women aged 40 to -49 years. In multivariate analysis, ptergyium was independently associated with increasing age (OR, 7.8; 95% CI, 3.2, 18.8 for persons 70 to 81 years, compared with 40 to 49 years), male sex (OR, 5.1; 95% CI, 2.9, 9.3) and certain occupations; factory workers, production workers and machine operators (OR, 3.1; 95% CI, 1.5, 6.3), as well as laborers and agricultural workers (OR, 3.3; 95% CI, 1.6, 7.0) had higher risks, compared with professionals and office workers. Grade 3 pterygium (n = 36) was also independently associated with male sex (OR, 11.6; 95% CI, 3.5, 38.6) and similar occupations but was not related to age. CONCLUSIONS: The prevalence of pterygium in Singapore is 7% among Chinese aged 40 years and older. Independent associations with increasing age, male sex, and occupations linked to outdoor work and other exposures suggest a multifactorial cause of this condition.

Adult↗
PubMed1999

Misoprostol used alone for the termination of early pregnancy. A review of the evidence.

Increased access to medical methods of abortion could significantly reduce maternal mortality, especially in developing countries. In light of the political and commercial difficulties in distributing the abortifacient mifepristone, the widely studied mifepristone-misoprostol regimen may not be sufficiently available in the near future. Thus, researchers have begun to look for alternative regimens, including regimens using misoprostol alone. This article reviews the current available evidence on the potential of a misoprostol-alone regimen for medical abortion. Although the data are varied and difficult to compare, recent studies indicate that a misoprostol-alone regimen could be safe and effective as a method of medical abortion. Misoprostol is widely marketed around the world for its other indications and is inexpensive, stable in tropical climates, easy to transport, and simple to administer. A misoprostol-alone regimen of medical abortion could thus greatly improve the access to safe medical abortion services by women in developing countries.

Abortifacient Agents, Nonsteroidal↗
PubMed2002

Distribution and sources of polycyclic aromatic hydrocarbons in the sediment of a sub-tropical coastal wetland.

Sediment cores (0-35cm below surface) from twelve sampling stations in the Mai Po and Inner Deep Bay Ramsar Site of Hong Kong were retrieved in the period March-December 1999. Vertical profiles of 15 priority polycyclic aromatic hydrocarbons (PAHs) in each sediment core were determined. Ranges of total PAH concentration, [sigmaPAH], in the wetland sediment were 0.18-0.83 (N = 0.36) microg/g dried sediment (mudflats) and 0.63-0.96 (x = 0.77) microg/g dried sediment (mangroves). A decreasing trend in depth averaged [sigmaPAH] was observed from the landward end towards the seaward end of the Marshes. On the mudflats, vertical profiles of the PAHs were quite uniform. At the fringe of the Mai Po mangroves, significantly higher concentration of all PAHs was observed at the upper 0 to -8 cm layer. No significant difference in the distribution patterns of the 15 priority PAHs in summer and winter was observed. This indicates that distribution of PAHs in the sediment of the Mai Po Marshes is not very sensitive to sub-tropical climatic changes of the region. Two PAH isomer ratios, [Phen]/([Phen] + [Anthra]) and [Pyrene]/([Pyrene] + [Fluoran]), were used to identify potential sources of PAH contamination in the wetland. Results revealed that local deposition is a more important source than long-range atmospheric transportation.

Aerosols↗
PubMed1996

Socioeconomic status and race as risk factors for cockroach allergen exposure and sensitization in children with asthma.

BACKGROUND: The domestic cockroach has been identified as an important source of indoor aeroallergens worldwide in both temperate and tropical climates. Because cockroach populations are highest in crowded urban areas, some have suggested that the increased asthma morbidity and mortality rates in inner cities could be related in part to cockroach allergen exposure. We have examined cockroach allergen exposure in the homes of children with asthma in both urban and suburban locations and have related the rates of exposure and sensitization to socioeconomic, racial, and demographic factors. OBJECTIVE: The study was designed to determine the independent contribution of race, socioeconomic status, and place of residence to the risk of cockroach allergen exposure and sensitization in children with asthma. METHODS: Eighty-seven children with moderate to severe allergic asthma, aged 5 to 17 years, participating in a prospective trial of immunotherapy, were evaluated. Extracted dust samples from three home locations were analyzed by using two-site monoclonal immunoassays for major cockroach allergens (Bla g 1 and Bla g 2). A puncture skin test with a mixed cockroach allergen extract was performed in 81 of the 87 subjects. RESULTS: In the 87 homes evaluated, 26% of the bedroom dust samples had detectable levels of cockroach allergen. In homes with detectable bedroom cockroach allergen levels, mean Bla g 1 and Bla g 2 concentrations in urban and suburban homes were similar. Over 80% of children with bedroom Bla g 1 or Bla g 2 of 1 U/gm or greater demonstrated skin sensitivity to cockroach allergen. The rate of cockroach sensitization was directly related to the level of bedroom exposure. African-American race was the only factor that was independently associated with cockroach allergen exposure (p = 0.05). Lower socioeconomic status, age greater than 11 years, cockroach exposure, and African-American race were all independently associated with cockroach allergen sensitization on the basis of stepwise multiple linear regression analysis. CONCLUSIONS: African-American race and low socioeconomic status were both independent, significant risk factors for cockroach allergen sensitization in children with atopic asthma. Cockroach allergen is detectable throughout the house, including the critical bedroom environment.

Adolescent↗
PubMed2006

[Tinea capitis in Madagascar: a survey in a primary school in Antsirabe].

BACKGROUND: Tinea capitis is a common infection among schoolchildren in developing countries. This condition is still under-reported in Madagascar. In order to assess the prevalence of Tinea capitis in Madagascar, we conducted a study in a primary school in Antsirabe, a town located in the country's high central territories. METHODS: Samples were taken from 210 children in the 4 school classes aged between 6 and 14 years. Only children with scaling lesions or with alopecia were sampled. No microsporic gray-patch ringworm was found in any of the children. Samples were obtained from a total of 83 children. Cotton swabs moistened with distilled sterilized water were rubbed on the children's scalps for 15 seconds and the scales thus collected were then seeded on 2 separate tubes of Sabouraud-Dextrose-Agar media containing chloramphenicol, one with and the other without cycloheximide. The tubes were incubated at a temperature of 27 degrees C for 4 weeks. All the micromycetes were identified (dermatophytes, yeasts and molds). RESULTS: Three species of dermatophytes were isolated: one anthropophilic species, responsible for black-dot ringworm (Trichophyton tonsurans), and 2 geophilic dermatophytes, unusual in human disease (Microsporum boullardii and Trichophyton terrestre). Of the 83 children sampled, 17 had 20 dermatophytes (in 3 children, 2 different species of dermatophytes were associated). We collected 15 Trichophyton tonsurans (2 Trichophyton tonsurans were associated with Microsporum boullardii, and 1 with Trichophyton terrestre), and 2 Microsporum boullardii. The prevalence of carriers of dermatophytes was 8 p. 100 for all children and 20.5% for the sampled children. DISCUSSION: Children in Madagascar, unlike those in Central Africa, do not develop microsporic gray-patch ringworm caused by Microsporum langeronii. However, they may present tinea capitis with small alopecic lesions, or they may frequently have Trichophyton tonsurans and seem to have healthy scalps. In contrast with Central Africa, where T. soudanense is the main cause of black-dot ringworm, and with North Africa, where T. violaceum is most frequently seen, these 2 species are not found in Antsirabe. Studies carried out in coastal regions with a more tropical climate could perhaps show other dermatophytes responsible for tinea capitis. Anthropophilic tinea capitis caused by Trichophyton tonsurans is endemic in the Antsirabe area. The lesions are inconspicuous with diffuse scaling, like those reported in surveys conducted in the USA. Mycological investigation followed up by topical treatment with a fungicide could diminish the spread of this anthropophilic, and thus contagious, dermatophyte. Trichophyton tonsurans has also reappeared regularly in France over the past few years.

Adolescent↗
PubMed2003

Varicella zoster virus immunity in multinational health care workers of a Saudi Arabian hospital.

INTRODUCTION: The health care worker (HCW) is vulnerable to hospital-acquired varicella zoster virus (VZV) infection, and thereafter may transmit infection to coworkers and patients who are susceptible and hospitalized. Interventions to prevent varicella transmission in HCW groups of uncertain immunity prove labor intensive, costly, and disruptive. Therefore, documentation of total varicella immunity in HCWs is desirable. SETTING: The National Guard King Abdulaziz Medical City is a 600-bed tertiary care center in Riyadh, Saudi Arabia with a multinational staff. MATERIAL AND METHOD: A program to assess the VZV status of HCWs was initiated in 1999. The survey was confined to HCWs having direct patient contact. Questions elucidated previous history of varicella (chicken pox) infection, antibody testing against varicella, and varicella vaccination. HCWs with a negative or unknown history were subsequently tested for varicella antibodies (IgG). RESULTS: Seventy-six percent (2,047) of the HCWs responded to the questionnaire. Of these, 562 (28%) were physicians, 761 (37%) were nurses, 438 (21%) were medical technicians, and 286 (14%) were involved in clerical work. A total of 802 (39%) were from the Middle East including Saudi Arabia, 633 (31%) were from the Far East, 361 (18%) were from the West and from temperate areas, 138 (7%) were from South Africa, and 113 (5%) were from other nationalities. A previous history of VZV infection was reported by 1303 (64%); 262 (13%) had a history of positive test for varicella antibody, and only 44 (2%) had a history of varicella vaccination. Of the 744 (36%) HCWs who had a negative or unknown history of VZV infection, 217 (29%) underwent antibody testing. Of these, 181 (83%) proved to be immune (IgG > or = 1.10), and 36 (17%) nonimmune (IgG < 1.2). The latter group have completed varicella immunization. Staff from the West (81%), Far East (78%), and South Africa (59%) reported more histories of VZV infection compared with the employees of Middle Eastern origin (46%) (P <.001) and disclosed a history of positive antibodies in 13%, 18%, 17%, and 8%, respectively (P <.001). In relation to occupation, nurses reported history of varicella infection (75%) and a history of positive varicella antibodies (16%) more than physicians (54% and 8%, respectively) (P <.05). Conversely, serologic immunity to VZV infection proved consistent among the different nationalities and among the 4 occupational groups. CONCLUSION: Total varicella immunity of a multinational workforce can be realized through screening of HCWs and vaccination of susceptible individuals. It is preferred above repeated interventions after varicella exposure for its simplicity, cost-effectiveness, and efficiency. Knowledge of VZV infection varies between different nationalities and cannot be used as a true predictor of immunity. There is no difference in the immunity by antibody testing of staff recruited from temperate and tropical climates. Total varicella immunity should, therefore, be achieved through screening of all HCWs and vaccination of those susceptible.

Antibodies, Viral↗
PubMed1984

Vaccinology of poliomyelitis.

Vaccinology requires not only an understanding of the fundamental properties of the immune system and specific immunogens, but also the application of basic knowledge to develop effective immunization programmes for particular social, political, and environmental conditions. Two problems exist in the use of oral, live poliovirus vaccine: the occurrence of vaccine-associated paralytic poliomyelitis and the uncertain antibody response in tropical climates. These difficulties can be overcome by the use of killed poliovirus vaccine formulated to be effective with a single dose. Application of basic principles can bring poliomyelitis fully under control in all parts of the world.

Administration, Oral↗
PubMed2002

Granulomatous lung diseases in the tropics.

International travel, changing immigration patterns, and political upheavals have transformed the epidemiological picture of many tropical granulomatous disorders [53]. These diseases are seen with an increasing frequency in the United States, Europe, and other developed countries. Physicians must now become familiar with illnesses that were previously regarded as being "exotic" because of this increasing prevalence. Accurate diagnosis is important because therapy is significantly different for infectious granulomatous disorders than for non-infectious diseases.

Diagnosis, Differential↗
PubMed2002

Adult respiratory distress syndrome in the tropics.

Today ARDS is more frequently recognized and managed in tropical countries, although published data from most locations is meager. The spectrum of disorders causing ARDS in tropical countries includes virtually all conditions encountered in the West. Additionally, tropical infections and other disorders are seen far more commonly. In particular, malaria and TB are important infections that predispose patients to ARDS in the tropics. Both of these illnesses give lead to severe forms of disease, such as falciparum malaria, acute miliary TB or TB bronchopneumonia, and may cause ARDS. Awareness of the complications helps in early recognition and differential diagnosis from several similar manifestations. Although earlier reports painted a gloomy picture of the outcome of these patients in general--mainly due to financial and logistic constraints--the scenario is improving quickly with better and wider availability of newer diagnostic and management tools.

Adult↗
PubMed2003

Factors related to cattle infestation level and resistance to acaricides in Boophilus microplus tick populations in New Caledonia.

Boophilus microplus, even in the absence of babesiosis, is a major disease of the cattle in New Caledonia where the particular farming system associates continental European breeds and a tropical climate tempered by the Pacific Ocean. In order to have a better understanding of the factors involved in cattle tick infestation, to decrease the possible wastage and use of chemicals and to increase the lifetime of the acaricides, the veterinary authorities investigated the conditions of the chemical treatments. A survey among 148 cattle farms of the whole of New Caledonia was carried out and factors that explain the development of tick resistance and cattle infestation have been determined. From this survey, three typologies for the main characteristics of the farms have been set up, the technical practices of the farmers and the tick control measures applied by the farmers, respectively. Some variables are significantly associated with the tick resistance to deltamethrin but their contribution to the explanation model is always moderate: farms in the south, with a positive resistance gradient from east to west, absence of bush fire and membership to a cattle farmers organization. The more the farmers have intensified their breeding-male castration, weaning, heifer separation, drenching, etc.-and pasture-high stock rate, mowing, extra feeding of the cows, many paddocks, etc.-techniques, the higher was the probability for the ticks in their farm to be resistant to deltamethrin. The technical details of the acaricide treatment had a low contribution to the explanation model. However, the use of a spray generated more resistance than a dip. Furthermore, there is a negative resistance gradient when the farmers increased the treatment interval average. Considering infestation, none of the variables from the three typologies were associated with the two infestation variables (1: semi-engorged tick females and 2: other ticks) at the herd level. However, the seven studied variables-the three typologies, breed, age, body condition score and breeding status-affected significantly the two infestation variables at the cow level, but their predictive ability remained very low (R(2)<3.5%). This result-individual effect more important than herd effect on the infestation-is confirmed by the importance of the variance of the intra-farm factors (99%) when compared with inter-farm factors (1%). Cows of Charolais breed, in poor body condition, old, pregnant or lactating, and those of the farms with irrational and high pressure control of ticks are the most infested.

Agriculture↗