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PubMed1997

Stability of essential drugs in the field: results of a study conducted over a two-year period in Burkina Faso.

To evaluate the stability of essential drugs stored in realistic tropical conditions, we have carried out a two-year prospective study in western Burkina Faso. Twenty-seven essential drugs were stored in a rural site and a urban one where temperature and hygrometry were recorded daily. Samples of each drug were taken for further analysis to the World Health Organization Collaborative Center for the Study of Stability of Drugs in Nantes, France every three months. Quantitative analysis showed that the majority of samples suffered no significant loss of their active ingredient. In contrast, ampicillin, erythromycin, sulfaguanidine, injectable furosemide, penicillin G, trimethoprim, and chloroquine showed more than a 10% quantitative loss of their active ingredient. Thus, it is not recommended that these essential drugs be stored for more than one year in a tropical climate.

Burkina Faso↗

PubMed1988

Assessment of a physical training program in patients with myocardial infarction in a tropical country.

Twenty-five myocardial infarction patients, included in a comprehensive cardiac rehabilitation programme, were studied in order to assess the physical training effects upon several physiological parameters in a country with a tropical climate. Training consisted of three-times weekly supervised sessions with running, under telemetric control, accomplished continuously, during thirty minutes at 120 m/min as mean speed. Symptom-limited exercise stress testing was initially performed and repeated after three months of training. 88% of patients showed an increase in physical working capacity, 84% in exercise time duration and 80% in the myocardial efficiency index at subsequent ergometries. A decrease of double product and submaximal heart rate was observed. Angina, ECG ischaemic alterations and arrhythmias during exercise in the first test disappeared or occurred with higher workload in the second ergometry. Mean resting acid concentration, 1.28 +/- 0.36 mmol/l, increased immediately after exercise to 2.03 +/- 0.58 mmol/l. The prescribed physical training programme showed satisfactory results and increased the patients' quality of life, even in a humid and moderately hot climate.

Cuba↗

PubMed1989

Unusual ultrastructural features in the superficial pineal gland of the yellow-bellied country rat (Rattus losea Swinhoe).

The ultrastructure of the superficial pineal gland of the yellow-bellied country rat (Rattus losea Swinhoe), living under natural climatic conditions at the margin of the tropical region, was studied with special reference to the seasonal changes. In the rainy season with average monthly rainfall of 400 mm (light phase of 13.5 h, and temperature of 28 degrees C) the gland was characterized by the presence of frequent large vacuoles containing flocculent material (LVFs), large condensed inclusions (LCIs) in the pinealocytes, and extensive accumulations of presumptive secretion in the extracellular compartment, suggesting an enhanced secretory activity. In the dry season with average monthly rainfall of 13 mm (light phase of 11 h, and temperature of 19 degrees C), however, the pinealocytes were characterized by the presence of numerous clear spindles, which exhibited acid phosphatase activity; at this time there were few LVFs and LCIs and rare extracellular accumulations, suggesting a declined glandular activity. We conclude that the cellular activity of the pineal gland in R. losea, living under tropical climatic conditions, is synchronized with the annual changes of rainfall, which is apparently more important than the annual changes of photoperiod and temperature.

Animals↗

PubMed1998

Adult susceptibility to varicella in the tropics is a rural phenomenon due to the lack of previous exposure.

In the industrialized countries of the West, varicella is largely a childhood disease, whereas reports from tropical countries indicate a significant incidence of varicella among adults. High ambient temperature, epidemiologic interference from other viruses, and race have been blamed. We tested our hypothesis that less exposure to varicella-zoster virus (VZV) during childhood in rural areas accounts for the reported greater frequency of varicella in adults in tropical climates by comparing rates of VZV seropositivity among urban and rural adult Bengalee populations living in identical climatic conditions in India. Only 5 (3.4%) of 153 urban adults were seronegative compared with 74 (31.1%) of 246 rural adults. Ninety-six percent of urban adults were immune by the age of 25, compared with 42% in the rural group. The results suggest that higher adult susceptibility to varicella is seen only in rural areas of the Tropics and is due to reduced transmission of VZV.

Adult↗

PubMed1988

The effect of tropical ambient temperature on growth and metabolism in pigs.

Three experiments involving 34 individually fed pigs were conducted in Guadeloupe (16 degrees Lat. N., 61 degrees Long. W.) to determine the effects of environmental temperature (tropical, 22 to 32 degrees C, vs thermoneutral, 17 to 21 degrees C) and feeding method (restricted vs ad libitum) on performance, carcass characteristics and physiological and metabolic responses of pigs at three weight ranges (8 to 25, 29 to 50 and 54 to 79 kg live weight). Compared with the control environment, the tropical climate increased rectal temperature and respiratory rate but depressed growth rate and efficiency of feed utilization. In addition, in the heaviest weight group, feed intake was reduced and body fat increased. Changes in metabolic status, such as increased concentrations of plasma free fatty acids, triglycerides, cholesterol and adipose tissue lipoprotein lipase activity were observed in pigs housed in the tropical environment. Moreover, in these pigs, there was a decreased plasma concentration of thyroid hormones (triiodothyronine and thyroxine). These results indicate that tropical ambient temperature markedly affects the metabolism of pigs and, therefore, probably influences their nutritional requirements.

Animals↗

PubMed2000

Sorption of imidacloprid and its metabolites on tropical soils.

The sorption of imidacloprid (1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolid-inimine ) (IMI) and its metabolites imidacloprid-urea (1-[(6-chloro-3-pyridinyl)-methyl]-2-imidazol-idinone) (IU), imidacloprid-guanidine (1-[(6-chloro-3-pyridinyl)-methyl]-4,5-dihydro-1H-imidazol-2-amine) (IG), and imidacloprid-guanidine-olefin (1-[(6-chloro-3-pyridinyl)methyl]-1H-imidazol-2-amine) (IGO) was determined on six typical Brazilian soils. Sorption of the chemicals on the soil was characterized using the batch equilibration method. The range and order of sorption (Kd) on the six soils was IG (4.75-134) > or = IGO (2.87-72.3) > IMI (0.55-16.9) > IU (0.31-9.50). For IMI and IU, Kd was correlated with soil organic carbon (OC) content and CEC, the latter due to the high correlation between OC and cation exchange capacity (CEC) (R2 = 0.98). For IG and IGO, there was no correlation of sorption to clay, pH, OC or CEC due to the high sorption on all soils. Average Koc values were IU = 170, IMI = 362, IGO = 2433, and IG = 3500. Although Kd and Koc values found were consistently lower than those found in soils developed in non-tropical climates, imidacloprid and its metabolites were still considered to be slightly mobile to immobile in Brazilian soils.

Absorption↗

PubMed2003

The fate of chloroacetanilide herbicides and their degradation products in the Nzoia Basin, Kenya.

Alachlor, metolachlor and their respective environmentally stable aniline degradation products, 2,6-diethylaniline and 2-ethyl-6-methylaniline were analyzed in water and sediment samples from 9 sites along River Nzoia, Kenya using gas chromatography. The degradation products were detected in > 90% of the sediment and water samples, while the parent compounds occurred in < 14% of the water samples. Much higher concentrations of the pesticides and their degradation products occurred in the sediment than in the water (1.4 up to 10 800-fold), indicating an accumulation of the compounds in the sediment. The constant occurrence of the degradation products in the sediment during the study period infers a persistence of these compounds. It is hypothesized that the prevailing tropical climatic conditions favor a quick breakdown of the pesticides to their environmentally stable degradation products, thereby making the latter more important pollutants than their parent products in the study area.

Acetamides↗

PubMed2004

Time-of-day effects in maximal anaerobic leg exercise in tropical environment: a first approach.

The aim of this study was to establish the effect of time of day on maximal anaerobic leg power in a tropical environment (French West Indies). Twenty-three physical education students (15 males and 8 females) who trained 10.5 hours a week (SD 6) volunteered to participate in the study. Their mean age, height and body mass were 22.8 (SD 3) years, 172.6 (SD 8) cm, and 64.6 (SD 7) kg, respectively. The chronotype of all subjects was moderate or intermediate. Tests were scheduled at 08 : 00, 13 : 00 and 17 : 00 hours on separate days in random order and constant conditions (room temperature: 28.1 degrees C [SD 0.6], relative room humidity: 62.6 % [SD 3.4]). On test days, the subjects were first measured at rest for body mass, heart rate and rectal temperature and they then performed vertical jump tests and a force-velocity test. The results showed a time-of-day effect on rectal temperature, which was significantly (p < 0.005) higher by the afternoon (13 : 00 and 17 : 00) than the morning (08 : 00). However, our results failed to show any daytime variation in maximal anaerobic power under the influence of tropical climate, which suggests that a hot and humid environment may have blunted the time-of-day effect by a passive warm-up effect.

Adult↗

PubMed1985

Observations on semen quality of dogs in the tropics.

Semen was obtained from eight mongrels and 17 purebred dogs kept in a tropical climate. The mean spermatozoal output per ejaculate was 303.6 +/- 138.2 and 602.9 +/- 466.2 million, respectively. Values for individual progressive motility, live and abnormal spermatozoa were comparable with those obtained in temperate regions. The type and frequency of spermatozoal abnormalities are illustrated.

Animals↗

PubMed1990

Development and characterization of the IOR/Hab inbred mouse strain.

The IOR/Hab inbred mouse strain, developed and maintained in the National Institute of Oncology and Radiobiology, is the first inbred strain to be developed in Cuba. It has a high fertility in this tropical climate. A number of physiological characteristics such as longevity, haematological characteristics, and growth are reported. Other experiments and results concerning spontaneous tumour frequency suggest that the strain is well adapted to standard environmental conditions, and could be useful for biomedical research.

Animals↗

PubMed2000

[Seasonal evolution of the biogeochemical cycle in the southwest lagoon of New Caledonia. Application of a compartmental model].

A biogeochemical box model describing the south-west lagoon of New-Caledonia was developed in order to simulate the seasonal cycle of carbon and nitrogen. We used fluxes generated by a 3D hydrodynamic model to simulate horizontal exchanges between boxes and added freshwater influxes as nitrogen sources from the land. Average residence time proved to be less than 11 days for the lagoon as a whole. Standard simulations showed baseline values of chlorophyll a between 0.2 and 0.4 microgram.L-1. Influences of freshwater influxes proved to be significant (increases up to 1 microgram.L-1) only in shallow areas protected from wind exposure and during short periods of heavy rainfall (tropical depressions). Tropical climatic events have reduced impact in space and time and long-term simulations over decades with increased nutrient inputs did not show any significant process of eutrophication. Hydrodynamics seemed to be one of the major control factors with respect to organic matter cycling in the lagoon.

Chlorophyll↗

PubMed2002

Dried blood spots (DBS): a valuable tool for HIV surveillance in developing/tropical countries.

Dried blood spots (DBS) on filter paper have been used as a practical method of sample collection in sero-surveillance studies of numerous diseases. DBS may be particularly useful for HIV screening in remote areas, in which unrefrigerated transfer time to a laboratory may take a number of days. In this study, we evaluate the ability to detect human immunodeficiency virus (HIV) type-1 antibodies from DBS that have been subjected to a tropical climate in southern India for 6 days. DBS were prepared from blood samples of 59 known HIV-positive individuals and 30 known HIV-negative individuals. ELISA and Western blot results from DBS that were subjected to a mean temperature of 35.8 degrees C and humidity of 73% for 6 days had a sensitivity of 100% and 92%, respectively, and a specificity of 100% and 100%, respectively. Based on these findings, we conclude that DBS sampling could serve as a cost-effective and convenient tool for widespread HIV sero-surveillance in remote areas within tropical countries.

AIDS Serodiagnosis↗

PubMed1992

[Otitis externa in tropical diving and swimming].

Studies of the microflora of the external auditory canal should help to clarify the frequent acute diffuse external otitis which may occur in recreational scuba-divers and swimmers during a stay in the tropics. We found that colonisation with facultatively pathogenic microorganisms increased after exposure. Apart from this contamination, indirect factors such as the tropical climate and intensive exposure to water may play an important role in the aetiology of the external otitis. For individual preventive measures, topical application of paraffin-oil before, and an aqueous solution of alcohol and acetic acid after exposure are recommended.

Acetates↗

PubMed1991

Diagnostic Mr 31/32000 proteins of Schistosoma mansoni (Sm31/32) and S. haematobium (Sh31/32): stability and reaction conditions for prospective field tests.

The existence of adult Schistosoma haematobium worm proteins (Sh31/32) homologous to the diagnostic Sm31/32 of S. mansoni is shown. Sm31/32 and Sh31/32, adsorbed on nitrocellulose and kept dry on the bench before immunoblot analysis, were antigenically stable for at least 4 years including storage for 17 months in tropical climates. The antigens react with patient sera in the absence of defined buffers under rather simple conditions ("humid chamber blot"). The results add to the use of these antigens for serodiagnosis of schistosomiasis in endemic areas.

Animals↗

PubMed1995

Circadian and seasonal variation of the body temperature of sheep in a tropical environment.

Nychthemeral and annual rhythms of the rectal temperature were determined for Corriedale sheep in a tropical climate. The minimum rectal temperature averaged 39.55 degrees C at 0500 hours in summer, and 38.87 degrees C at 0600 hours in winter. The maximum was 40.03 degrees C in summer (1700 hours) and 39.33 degrees C in winter (1830 hours). Annual cycle of the rectal temperature showed a minimum in July and maximum in December.

Animals↗

PubMed1990

[The energy requirements of Holstein-Friesian heifers during rearing and pregnancy under the tropical conditions of Cuba. 1. Determination of dry matter and energy assimilation and of the live weight development and energy expenditure].

In an individual feeding experiment with 48 Holstein-Friesian heifers divided into 3 groups, the effect of various energy levels on live weight development and energy expenditure in the age bracket of 97 days (78 kg live weight) to conception (350 kg LW) and from conception to calving (500 kg LW) was investigated. Rations with differing concentrate--roughage ratios were used. The differentiation of energy intake per day between groups 1 and 2 and group 3 amounted to 7.5% in the 1st development period and to 20% between group 1 and groups 2 and 3 in the 2nd development period. There were significant differences in the live weight gain of 95 g/animal and day in the first development period (up to conception) and of 81 g/animal and day in the second period of development (from conception to calving). Under the tropical climatic conditions the energy expenditure in these studies was approximately 10% under the energy expenditure recommended by the NRC (1978). While there was a clear reciprocal relation between energy expenditure and live weight gain in the first period of development, this relation was less distinct in the second period of development.

Age Factors↗

PubMed2004

Behavior and pollination efficiency of Nannotrigona perilampoides (Hymenoptera: Meliponini) on greenhouse tomatoes (Lycopersicon esculentum) in subtropical México.

The acclimation, foraging behavior, and pollination efficiency of stingless bees of the species Nannotrigona perilampoides Cresson were evaluated in tomato (Lycopersicon esculentum Mill.) plants cultivated in two greenhouses. The greenhouses were divided into three areas of 16 m2, and one of the following treatments was used for pollination: stingless bees (SB), mechanical vibration (MV), and no pollination (NP). Observations were conducted once a week from 0800 to 1600 hours during 2 mo. The acclimation of the bees to the greenhouses was estimated by the number of bees that did not return to the hive (lost bees) and by comparing the population of the colonies (brood and adults). The foraging activity of the bees across the day was evaluated by comparing the number of foragers per hour. The influence of environmental variables on the foraging activity was also analyzed. The pollination efficiency was compared among treatments through the percentage of fruit set, weight of individual fruit, kilograms of fruit produced per square meter, and the number of seed per fruit. The bees started foraging on the flowers approximately 7 d after the colonies were introduced to the greenhouse. There was a decline in the population of the colonies across the experiment, but colonies did not die out. Correlations of environmental variables with the foraging activity of the bees showed that none of them had a significant influence on pollen foraging. However, water collection was positively correlated with the temperature and negatively correlated with the humidity inside the greenhouse. The estimation of the pollination efficiency per treatment showed that there were significant differences in fruit set in SB (83 +/- 4.2) and MV (78.5 +/- 6.4) compared with NP (52.6 +/- 7.6). However, the average weight of the fruit was similar for the three treatments (65 g). There were significant differences for seed number in SB (200 +/- 15.3) and MV (232 +/- 21.4) compared with NP (120 +/- 16.6). The productivity in kilograms of fruit per square meter was higher in SB (5.72 +/- 0.61) and MV (5.66 +/- 0.58 kg) compared with NP (3.34 +/- 0.72). The number of seed was positively correlated with the weight of the fruit. We conclude that the use of Nannotrigona testaceicornis Rondani, for pollinating greenhouse tomatoes in tropical climates, could be an alternative to the use of highly defensive African-derived Apis mellifera or non-native bumble bees (Bombus spp.). However, more research is needed to evaluate the cost/benefit on large-scale greenhouse pollination using N. perilampoides Cresson against other bee species and pollination methods.

Agriculture↗

PubMed2001

Metabolism of fluvalinate in chickpea plants under sub-tropical conditions of northern India.

The metabolism of fluvalinate in chickpea plants in the field under sub-tropical climatic conditions has been investigated. Ten days after spraying with fluvalinate, leaves were collected and extracted in acetone. The extract was fractionated and the metabolites were identified by co-chromatography using TLC, GLC, and GC-MS. The anilino acid, a metabolite derived from ester cleavage, was the major metabolite present as both free and conjugated forms in chickpea leaves. 3-PBacid and 3-PBalc were minor metabolites. Glucose was found to be the major sugar conjugating with the metabolites.

Agriculture↗