[Tropical climate, exotic diseases. 3. The effect of tropical climate on the neuroendocrine system].
Explore the source record for details and available documents.
Adaptation, Physiological↗
SEARCH · PubMed Health
Results for “TROPICAL CLIMATE”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
[The adaptation of flying personnel to the tropical climates of West Africa].
Explore the source record for details and available documents.
Acclimatization↗
Anthropological and thermoregulatory changes induced by a survival sojourn in a tropical climate.
OBJECTIVE: A survival sojourn in a tropical climate exposes subjects to 2 main constraints: food restriction and tropical climatic conditions. We hypothesized that such a sojourn could modify anthropological characteristics and thermoregulatory responses to heat and cold on return. METHODS: Eight European male subjects were submitted to a sweating test (ST) for 90 minutes (dry bulb temperature [Tdb] = 47 degrees C, relative humidity (RH) = 10%, and wind speed = 0.8 m x s(-1)) and to a whole-body cold-air test (Tdb = 1 degrees C, RH = 40%, and wind speed = 0.8 m x s(-1)) for 120 minutes in thermoclimatic chambers both before and after a 4-week survival sojourn in French Guyana. RESULTS: The survival sojourn resulted in a decrease in lean body mass (P < .05) without any significant change in body fat content. Heat thermoregulatory changes studied during the ST were characterized both by a lower mean skin temperature (Tsk) (P < .05) and a higher sweat rate measured after the sojourn than before it (m(sw); P < .05). Cold thermoregulatory changes were characterized by a higher T(sk) value (P < .05) and a decreased onset for continuous shivering without any significant change in internal temperature or metabolic heat production (M). CONCLUSIONS: This study showed that this type of sojourn modifies not only biometrical characteristics of the subjects but also the thermoregulatory responses, inducing an adaptation of the thermoregulatory system to heat and an increase in the sensitivity of the thermoregulatory system to cold. This finding could have practical implications on return after such a sojourn.
Adaptation, Physiological↗
Drug formulations intended for the global market should be tested for stability under tropical climatic conditions.
RATIONALE OBJECTIVE: The quality of drugs imported into developing countries having a tropical climate may be adversely affected if their formulations have not been optimized for stability under these conditions. The present study investigated the influence of tropical climate conditions (class IV: 40 degrees C, 75% relative humidity) on the drug content, in vitro dissolution and oral bioavailability of different formulations of two essential drugs marketed in Tanzania: diclofenac sodium and ciprofloxacin tablets. METHODS: Before and after 3 and 6 months storage under class IV conditions the drug content and in vitro dissolution were evaluated using United States Pharmacopoeia (USP) 24 methods. Following a randomized four-period cross-over study, the pharmacokinetic parameters of drug formulations stored for 3 months under class IV conditions were compared with those stored at ambient conditions. RESULTS: Drug content and drug release from all tested ciprofloxacin formulations were within USP-24 requirements and remained stable during storage at simulated tropical conditions. Oral bioavailability was also not influenced by tropical conditions. The dissolution rate of two diclofenac formulations (Diclo 50 manufactured by Camden and Dicloflame 50 manufactured by Intas) reduced significantly during storage under class IV conditions. After oral administration Camden tablets stored for 3 months under class IV conditions showed a reduction in C(max) (90% CI of C(max) ratio: 0.59 - 0.76). This reduction was smaller than expected based on the in vitro tests. CONCLUSIONS: Some drug formulations imported into Tanzania are not optimized for stability in a tropical climate. Manufacturers and regulatory authorities should pay more attention to the WHO recommendations for testing the stability of drugs under tropical climate conditions. Efforts should be made to improve the in vitro tests to better predict the bioavailability.
Administration, Oral↗
Instability of (methyl)ergometrine in tropical climates: an overview.
Parenteral ergometrine is widely used for the prevention and treatment of excessive uterine bleeding following birth. Unfortunately, in tropical climates it is often found to contain very little active ingredient: only 32 of 100 field samples from Bangladesh, Gambia, Malawi, Yemen and Zimbabwe contained 90-110% of the amount of active ingredient stated on the label, and 34 contained less than 60%. In this paper the results of nine studies, of which eight were initiated and coordinated by WHO, are reviewed to formulate answers to the following questions: (1) what is the extent of the problem of low potency of ergometrine in tropical climates; (2) is the problem due to instability or low initial quality, or both; (3) which practical measures can assure the quality of injectable ergometrine; and (4) are there any alternative drugs which are more stable? Injectable ergometrine is very unstable under tropical conditions and particularly if stored unrefrigerated and exposed to light, when it may loose up to 20% of its potency per month. However, there are differences between brands. Practical measures to assure the quality of injectable ergometrine therefore include a careful supplier selection and refrigerated storage. Ergometrine injection should always be protected from light until given to the patient. Loss of active ingredient can easily be detected by regular visual checks of the colour of the solution. Any discoloration implies that the solution contains less than 90% of the stated amount of active ingredient, and should not be used. Methylergometrine is no more stable than ergometrine. Parenteral oxytocin is more stable than both ergometrine and methylergometrine injection. Oral and buccal dosage forms are less stable than injections. In view of the better stability in tropical climates, similar cost, fewer side effects and comparative efficacy, parenteral oxytocin, rather than parenteral ergometrine, is the drug of choice in the prevention and treatment of postpartum haemorrhage.
Administration, Oral↗
Effect of fourteen days of acclimatization on athletic performance in tropical climate.
In order to study the acclimatization process over 14 days of exposure to tropical climate, 9 triathletes performed 4 outdoor indirect continuous multistage tests in both thermoneutral and tropical conditions. The thermoneutral test (TN, 14 degree C, 45% rh) was performed before traveling to the tropical area (Martinique, FWI). The tropical tests were performed 2, 8, and 14 days after arrival (32.9 degree C, 78% rh). During each trial, we measured tympanic temperature, sweat rate, body mass loss, heart rate (HR), and performance. The results showed that 1). the mean tympanic temperature was greater in T2 (P <.001), T8 (P <.01) and T14 (P <.01) than in TN and significantly lower in T14 than in T2 (P <.05); 2). the mean sweat rate was significantly greater (P <.001) in T2, T8 and T14 than in TN and significantly greater (P <.05) in T8 and T14 than in T2; 3). the body mass loss after trials was significantly greater (P <.001) in T2, T8 and T14 than in TN and significantly greater (P <.05) in T8 and T14 than in T2; 4). the mean HR and HR at rest were significantly higher (P <.005) in T2 than in TN, T8, T14 and the mean HR was significantly lower (P <.05) in T14 than in the other trials; and 5). the performance time was significantly lower in T2 (P < 0.02), T8 (P < 0.03) and T14 (P < 0.05) than in TN. We concluded that 14 days of exposure to tropical climate led to changes in physiological parameters but were still insufficient to ensure complete acclimatization in well-trained athletes. The hot/wet climate induced impairment of physiological responses and performance that were still evident on the 14th day.
Acclimatization↗
Effect of tropical climate on performance during repeated jump-and-reach tests.
AIM: The aim of the present study was to determine the effect of tropical climate (i.e., hot and humid) on performance during multiple jump-and-reach tests. METHODS: Fourteen male basketball players volunteered to perform 2 randomized series of jump-and-reach tests, which consisted of a jump-and-reach test every 15 sec for 5 min (21 jump-and-reach tests) in two thermal conditions: tropical (TR, 30.4 degrees C, 70% rh) and thermoneutral (TN, 23.1 degrees C, 53% rh). During each test, lactate concentration [La(-)], tympanic temperature (Tty), sweat rate (SR), heart rate (HR), and performance (height: H) were noted at rest, during exercise and recovery. Two hours of recovery separated the TN and TR tests. RESULTS: There were no significant differences in mean height, maximal height or the kinetics between TN and TR. Both conditions induced an increase in height over time (time effect: p<0.002). There were no significant differences in [La(-)] at rest or during exercise or recovery in the 2 conditions. Both conditions induced an increase in [La(-)] (time effect: p<0.002). There was a tendency toward a higher mean [La(-)] during TR than TN (situation effect, p<0.07). However, compared to resting values, [La(-)] values were significantly increased only in TR and not in TN. Tty, was significantly greater (p<0.001) at rest and during exercise and recovery in TR than in TN. SR and HR were also significantly greater at rest and during exercise and recovery in TR (p<0.001 for SR and HR). CONCLUSION: We conclude that tropical climate affects physiological responses without improving or decreasing performance during successive jump tests.
Adult↗
Effects of dietary fiber on performance of multiparous lactating sows in a tropical climate.
Sixty-two multiparous Large White sows were used to determine the effect of dietary fiber level on lactation performance according to season under conditions of a humid tropical climate. This experiment was conducted in Guadeloupe (West French Indies, lat 16 degrees N, long 61 degrees W) between October 1999 and January 2001. Two seasons were distinguished a posteriori from climatic measurements parameters continuously recorded in the farrowing room. During the warm season, ambient temperature and relative humidity averaged 25 degrees C and 86.8%, respectively. The corresponding values for the hot season were 27.5 degrees C and 83.5%. Experimental diets fed during lactation were a control diet (C; 14% neutral detergent fiber) and a high-fiber diet (HF; 20% neutral detergent fiber) obtained by substitution of wheat middlings by wheat bran. The two diets were formulated to provide the same ratios between essential amino acids and lysine and between lysine and net energy. No interaction between season and diet composition was found for all criteria studied. Over the 28-d lactation, average daily feed intake (ADFI) was lower and body weight loss was higher (P < 0.001) during the hot season compared to the warm season (3,447 vs 4,907 g/d and 33 vs 17 kg, respectively). The number of stillborn piglets was higher (P < 0.05) during the hot season than during the warm season (2.0 vs 1.1 piglets, respectively). Litter growth rate and mean BW of piglets at weaning were reduced (P < 0.01) during the hot season vs the warm season (2.1 vs 2.3 kg/d and 7.7 vs 8.3 kg, respectively). The ADFI was similar for both diets and digestible energy (DE) intake tended to be lower (P = 0.06) with the HF diet (54.9 vs 59.3 MJ of DE/d for C sows) in relation with its lower DE concentration. The body weight loss was greater (P < 0.01) for HF sows than for C sows (30 vs 21 kg). Compared with the C diet, the HF diet increased (P < 0.05) litter growth rate and piglet body weight at weaning (2.3 vs 2.1 kg/d and 8.3 vs 7.7 kg/d for HF vs C, respectively). Season and diet composition did not affect the weaning-to-estrus interval. In conclusion, the hot season in humid tropical climates, which combines high levels of temperature and humidity, has a major negative effect on the performance of lactating sows.
Animal Feed↗
Influence of a hot/wet environment on exercise performance in natives to tropical climate.
AIM: The purpose of this study was to determine the influence of a hot/wet climate on thermoregulation and cardiac responses during a prolonged effort in natives to tropical climate. METHODS EXPERIMENTAL DESIGN: 22 healthy trained subjects volunteered to perform 3 trials of submaximal cycling of 1 hour each. Two of the trials were performed in a cool environment and the third, in tropical conditions. MEASURES: during all trials, we measured the evolution of tympanic temperature, water loss, heart rate performance. RESULTS: The results showed 1). a significant increase in core temperature (p>0.001), heart rate (p<0.0001), sweat rate (p<0.0005) and water loss (p<0.0001) and 2). a significant impairent in performance, estimated at 27.7% (p<0.01), in tropical conditions as compared with a cool environment. CONCLUSION: We concluded that intensive and prolonged exercise in a hot/wet climate induces an overload regarding thermoregulatory and cardiac responses even in natives to tropical climate. The impaired physiological responses constitute a limiting factor for aerobic performance.
Adult↗
[Primary non-adaptation syndrome to tropical climates].
Explore the source record for details and available documents.
Climate↗
Effects of 8 days acclimation on biological and performance response in a tropical climate.
BACKGROUND: This study was designed to determine the acclimation process elicited by exposure to a tropical climate. METHODS: Nine triathletes performed 3 outdoor indirect continuous running multistage tests in both thermoneutral and tropical conditions. Before travelling to the tropical area (Martinique Island, FWI), the triathletes performed the thermoneutral test (TN) in 14 degrees C and 45% rh conditions. The tropical tests were performed 2 and 8 days after arrival (T2 and T8, performed at a mean environmental temperature of 33.4 degrees C and 75.5% rh). The day before T8, blood samples were drawn for biochemical analysis. During each test, tympanic temperature, sweat rate, weight loss, heart rate (HR), and performance were recorded. RESULTS: The results demonstrated that: 1) the mean tympanic temperature was greater in T2 (p<0.001) and T8 (p<0.01) than in TN; 2) the mean sweat rate was significantly greater (p<0.001) in T2 and T8 than in TN and significantly greater in T8 than in T2 (p<0.03); 3) the weight loss after trials was significantly greater (p<0.001) in T2 and T8 than in TN and in T8 than in T2 (p<0.04); 4) the mean HR and the HR at rest were significantly greater in T2 than in TN (p<0.001) and T8 (p<0.005); 6) significant reductions were observed in T8 vs TN in red cell count (p<0.05) and plasma proteins (p<0.04), the consequence of a 7.5% plasma volume expansion; and 7) the performance was significantly lower in both T2 (p<0.02) and T8 (p<0.03) than in TN. CONCLUSIONS: We concluded that 8 days exposure to hot/wet conditions induced impairments in physiological responses and performance that were still evident on the 8th day. Further and longer outdoor studies are needed to investigate if return to optimal performance levels after adaptation to hot/wet conditions is possible.
Acclimatization↗
Genetic and sex influences on the regional distribution of acetylcholinesterase activity in the porcine brain and hypophyses under humid tropical climatic conditions.
The adaptability of one indigenous and four exotic breeds of pigs to the humid tropical climatic conditions of Ibadan was comparatively evaluated with acetylcholinesterase activity (AChE) of brain and hypophyseal parts as the parameter. Significant breed differences were observed in the weight and AChE of the hypophyses and in the AChE of the brain parts. With regard to sex, only the relative adenohypophyseal weight and the AChE of the cerebellum and medulla oblongata were influenced. The results demonstrate the greater adaptability of the indigenous pigs to their native environment than the exotic breeds. A reduced sensitivity to the various stressing factors of the indigenous pigs and the females was implied. Results also suggest that the Large White breed may be more suited to the conditions prevalent in Ibadan than the other exotic breeds.
Acetylcholinesterase↗
Field evaluation of protective equipment for pesticide operators in a tropical climate.
In order to extend the practical advice and information on personal protection when using pesticides in tropical climates, a GIFAP-FAO Working Group carried out a study on protective equipment worn by pesticide workers in hot and humid conditions in Thailand. Items assessed included protective garments worn by workers mixing and loading the organophosphorus insecticide formulation Tamaron and by spraymen applying the diluted formulation for several hours per day to a cotton crop with knapsack sprayers. The mixer-loaders also wore nitrile rubber gloves and a faceshield. The protective garments were made up of two pieces, an upper garment of a double apron design and separate trousers. Garments made up of different materials were assessed for their acceptability to the workers, their comfort and durability and their protectiveness against the insecticide. As a result of the study it is considered that cotton protective garments are appropriate for pesticide workers in these conditions if additional protection is necessary. The nitrile rubber gloves and faceshield were also found to be suitable for mixer-loaders in these circumstances. It is emphasized that the effective use of protective equipment must go hand in hand with safe handling precautions and the adoption of good personal hygiene.
Evaluation Studies as Topic↗
Seasonal affective disorder: some epidemiological findings from a tropical climate.
OBJECTIVE: To determine whether a predominantly summer-focussed pattern of seasonal affective disorder (SAD) exists in tropical northern Australia. METHOD: A mail survey containing a modified form of the Seasonal Pattern Assessment Questionnaire (SPAQ) was administered to 176 households in the city of Townsville (latitude: 19 degrees south). RESULTS: Using previously reported screening criteria, 9% of respondents reported a degree of summer impairment indicative of SAD, while the incidence rate for winter SAD was 1.7%. This summer-winter ratio is typically reversed in more temperate latitudes. CONCLUSIONS: Excessive heat and humidity were reported to be the two most influential environmental factors affecting mood and behaviour. It is likely that respondents meeting criteria for summer SAD represent the extreme end of a spectrum of summer-related mood and behaviour change that affects many individuals in northern Australia. Strategies for further clinical and epidemiological research on SAD in tropical climates are proposed.
Adolescent↗
[Effect of tropical climate on the androgenic activity of various strains of bulls].
By means of experiments the effect of a tropical climate on the androgenic activity of bulls expressed by the fructose level in the sperm was proved as well as a direct dependence of its concentration on the volume of the ejaculate and an indirect dependence on the density of spermatozoa. Besides this also its positive relation to the vitamin C level and to the polarographic and hemolytic activity of the sperm was proved. From the results obtained the conclusion has been drawn that the androgens affect the protein, vitamin and enzymic structures of the sperm.
Androgens↗
High seroprevalence of antibodies to varicella zoster virus in adult women in a tropical climate.
OBJECTIVES: To determine whether the seroprevalence of antibodies to varicella zoster virus (VZV) in adults is similar to that reported in tropical populations elsewhere. METHODS: We measured the seroprevalence of VZV IgG antibodies, using an enzyme immunoassay (EIA) in women attending an antenatal clinic in an urban centre in tropical Australia. RESULTS: The overall seroprevalence of VZV antibodies in 298 women was 92% (95% CI 88-95), with no difference between women who spent their childhoods in the tropics and colleagues. None of the overseas-born women was seronegative. CONCLUSION: The seroprevalence of VZV antibodies in this tropical population in Australia is as high as that reported from temperate regions, suggesting that social and cultural factors and population mobility are more important determinants of age distribution of VZV immunity than tropical climate.
Adolescent↗
[Physiometry of tropical climate].
Explore the source record for details and available documents.
Climate↗
Tepid sponging to reduce temperature in febrile children in a tropical climate.
The effectiveness of tepid sponging, in addition to antipyretic medication, in the reduction of temperature in febrile children living in a tropical environment, was assessed in a prospective, randomized, open trial. Seventy-five children aged between 6 and 53 months who attended the casualty department of the Children's Hospital, Bangkok, Thailand, with fever (rectal temperature > or = 38.5 degrees C) of presumed viral origin were randomized to received either tepid sponging and oral paracetamol (sponged group) or paracetamol alone (control group). Rectal temperature and the occurrence of crying, irritability, and shivering were recorded over the following 2 hours. A greater and more rapid fall in mean rectal temperature occurred in the sponged group than in the control group. Temperature fell below 38.5 degrees C sooner in children in the sponged group than in control children (P < 0.001). At 60 minutes, 38 (95.0%) of the controls still had a temperature of 38.5 degrees C or greater, compared with only 15 children (42.9%) in the sponged group (P < 1 x 10(-5). Crying was associated with sponging, but shivering and irritability occurred in only one child who was being sponged. It is concluded that tepid sponging, in addition to antipyretic medication, is clearly more effective than antipyretic medication alone in reducing temperature in febrile children living in a tropical climate.
Acetaminophen↗