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PubMedDate not supplied

Major constituents of the foliar epicuticular waxes of species from the Caatinga and Cerrado.

The epicuticular waxes of leaves of four species (Aspidosperma pyrifolium, Capparis yco, Maytenus rigida and Ziziphus joazeiro) from the Caatinga, (a semi-arid ecosystem of Northeast Brazil) and four species (Aristolochia esperanzae, Didymopanax vinosum, Strychnos pseudoquina and Tocoyena formosa) from the Cerrado, (a savanna ecosystem covering one third of the Brazilian territory), were analyzed. Six species contained a high content (above 60 microg x cm(-2)) of wax, four of them from the Caatinga. Triterpenoids and n-alkanes were the most frequent and abundant constituents found in the species from both habitats. The distribution of n-alkanes predominated by homologues with 27, 29, 31 and 33 carbon atoms, displayed no consistent differences between species from the two habitats. Lupeol, beta-amyrin, epifriedelinol and ursolic acid were the triterpenoids found. Triterpenoids clearly predominate over alkanes in the waxes from the Cerrado species. The waxes of two evergreen species from the Caatinga yielded n-alkanes as predominant constituents. A comparison of foliar epicuticular waxes of native plants from ecosystems with different hydric constraints is discussed.

Alcohols↗
PubMedDate not supplied

Pharmacokinetics, bioavailability and dosage regimen of sulphadimidine in camels (Camelus dromedarius) under hot, arid environmental conditions.

A two-way crossover study was conducted in young Bikaneri camels (aged between 12 and 18 months) during the hot summer season to determine the bioavailability, pharmacokinetics and dosage regimens of sulphadimidine (SDM). A dose of 100 mg.kg-1 of SDM was used to study both the intravenous and oral pharmacokinetics of the drug. Analysis of the intravenous data according to a two-compartment pharmacokinetic model revealed that SDM was well distributed in the body (Vd(area):0.862 L.kg-1), had an overall body clearance of 0.035 +/- 0.019 L.h-1.kg-1 and the elimination of half-lives was in the range of 14.2 to 20.6 h. The mean maximum plasma SDM concentration following oral administration was 63.23 +/- 2.33 micrograms.mL-1, which was achieved 24 h after the oral administration. The mean bioavailability of SDM following oral administration was approximately 100%. To achieve and maintain the therapeutically satisfactory plasma sulphadimidine levels of > or = 50 micrograms.mL-1, the optimum dosage regimen for camels following either intravenous or oral administration would be 110 mg.kg-1 as the priming dose and 69 mg.kg-1 as the maintenance dose, to be repeated at 24 h intervals.

Animals↗
PubMed1990

An Antarctic research outpost as a model for planetary exploration.

During the next 50 years, human civilization may well begin expanding into the solar system. This colonization of extraterrestrial bodies will most likely begin with the establishment of small research outposts on the Moon and/or Mars. In all probability these facilities, designed primarily for conducting exploration and basic science, will have international participation in their crews, logistical support and funding. High fidelity Earth-based simulations of planetary exploration could help prepare for these expensive and complex operations. Antarctica provides one possible venue for such a simulation. The hostile and remote dry valleys of southern Victoria Land offer a valid analog to the Martian environment but are sufficiently accessible to allow routine logistical support and to assure the relative safety of their inhabitants. An Antarctic research outpost designed as a planetary exploration simulation facility would have great potential as a testbed and training site for the operation of future Mars bases and represents a near-term, relatively low-cost alternative to other precursor activities. Antarctica already enjoys an international dimension, an aspect that is more than symbolically appropriate to an international endeavor of unprecedented scientific and social significance--planetary exploration by humans. Potential uses of such a facility include: 1) studying human factors in an isolated environment (including long-term interactions among an international crew); 2) testing emerging technologies (e.g., advanced life support facilities such as a partial bioregenerative life support system, advanced analytical and sample acquisition instrumentation and equipment, etc.); and 3) conducting basic scientific research similar to the research that will be conducted on Mars, while contributing to the planning for human exploration. (Research of this type is already ongoing in Antarctica).

Antarctic Regions↗
PubMed1973

Antarctica as a Martian model.

Previous investigators have reported that the microbiological population of the glacier free valleys of southern Victorialand, Antarctica, is sparse, and that from about 10% of the soil samples examined no micro-organisms could be cultivated. Since these areas are assumed to be more favorable to the growth of terrestrial organisms than any Martian environment, the previous authors concluded that the probability of terrestrial organisms growing on Mars would therefore be so small that sterilization standards could be relaxed by many orders of magnitude. The unsuitability of the Antarctic environment to the multiplication of terrestrial micro-organisms was ascribed by them to limiting amounts of water. We have carried out a survey of a variety of environments in the dry valleys, ranging from mountain crests to valley floors. The main purpose of our investigation was the determination of active microbial multiplication in the soil. A series of techniques was employed which permitted the detection of bacterial growth in situ. All evidence points to an active growth of micro-organisms in the Antarctic soil in all locations which we examined. The measurements were supported by electron micrographs of soil films which showed colonial growth covering soil particles. These findings suggest that Antarctica does not serve as a useful model for the Martian environment in evaluating quarantine standards.

Antarctic Regions↗
PubMedDate not supplied

[Neuroscience in ancient Egypt and in the school of Alexandria].

INTRODUCTION: About five thousand years ago, one of the most ancient, important and enduring civilisations in the history of Mankind flourished on the banks of the Nile. In Egypt, all the branches of human knowledge attained a high degree of development and today it is considered the mother of medicine. Despite the marked religious component that affected all its activities, the medicine of the Pharaohs was practised in a rational and deductive manner, and the Egyptians were the inventors of clinical observation. METHOD: The desert climate of the Nile Valley has preserved monuments, mummies and papyruses which have enabled us to get a certain idea of the degree of development reached in medical matters. The aim of this work is to analyse them from a neuroscientific point of view. The anatomical discoveries of the Egyptians originated in the inspection of wounds and the practice of embalming. They came to know a large number of diagnoses and were able to prescribe many different forms of treatment. They also attained a certain proficiency in dealing with neurotraumatological patients. They practised anamnesis, prognostics and a regulated surgery that infrequently included trephination. Their conservatism meant that, after the Macedonian domination, the traditional Egyptian medicine was replaced the Greek medicinal arts, which reached their maximum period of splendour in the School of Alexandria, where Herophilus and Erasistratus, pioneers in the study of anatomy and brain circulation, were especially renowned. CONCLUSIONS: From the point of view of the neurosciences, the Egyptians were the first to describe the brain, migraine, epilepsy, strokes, tetanus, Bell s palsy and the sequelae of head injuries and of spinal transection. Their artwork sometimes shows neurological patients and, according to Herodotus, there were doctors who were specialised in head diseases and could therefore be considered the precursors of our present day neurologists.

Egypt, Ancient↗
PubMed1954

Inhalant allergens in Palm Springs, California.

Although Palm Springs, California, offers a pleasant desert climate that is often advantageous in treatment of respiratory allergies, physicians should be made aware in referring their patients that definite pollen factors must be taken into consideration in recommending a visit to Palm Springs, and should try to determine the compatibility of their patient's allergic sensitivity pattern and the particular seasonal incidence of pollen concentration in Palm Springs. It is believed that the most important pollens there are those of Bermuda grass, olive tree, mesquite, dicoria, false ragweed, scales, and hymenoclea salsola. A favorable climate alone does not permit a patient to disregard good allergic management.

Allergens↗
PubMed1989

An aerobiological survey of allergens in al Khobar, Saudi Arabia.

A nationwide aerobiologic study is in progress in Saudi Arabia using Burkard 7-day volumetric spore traps to determine the major airborne allergens and their seasonal patterns. Eights months readings have been completed at Al-Khobar, an important coastal city on the Arabian Gulf. Pollen levels showed a double season. An autumnal peak reached its maximum in October rising sharply from the low summer values before falling during the short winter then rising again in springtime. Both local and imported flora were represented with chenopodiaceae, grasses and Ambrosia as the most common botanical groups, identification of the most significant individual species is still in progress. Fungal spores also show distinctive seasonal patterns. In descending rank order from the most common genera were Cladosporium, Ustilago, Alternaria, with Chaetomium and Ulocladium as consistent but minor components. Basiodiospores and Ascospores represented less than 10% of the total spore population, indicative of the dry nature of the climate. Desert dust added an important irritant to the Saudi atmosphere but a major contaminating factor to the aerobiological material being analysed.

Aerosols↗
PubMed1977

Effect of environments on human functions: studies on water metabolism.

The purpose of this review is to study general behaviour of human systems with respect to the environmental conditions. This type of work will be of profound significance to record the effect of medical treatment in various climatic zones of the world (Arayne and Saify, 1975). We attempted to discuss various facts which would be helpful for tackling the health problems of the people residing in these areas. The statistical data is avoided at the moment and a descriptive pattern is adapted in order to express views, about one of the important aspects of medical science.

Adaptation, Physiological↗