Influence of larval and pupal products on the oviposition behavior of Aedes Fluviatilis (Lutz) (Diptera: Culicidae)

Several larval and pupal products of Aedes fluviatilis (Lutz) were tested for their influence on the oviposition behaviour of females of the same species. Significant (alfa = 0,05) atractiveness was shown by: larval water, previously containing 5 to 15 larvae/1,5 ml; larval water, preserved up to 38 days; evaporate and reconstructed larval water extracts up to 2 years after production and water filtered through fresh or dried ground larvae. hexanic larval water extracts and water filtered through fresh or dired ground pupae did not influence oviposition.

Immunopathology of american cutaneous leishmaniasis. Modulation of MHC class II gene products by Keratinocytes before and after glucantime therapy

Epidermal changes from 32 cutaneous and 3 mucosal American leishmaniasis (ACL) active lesions were studied for HLA-DR, -DP expression, Lanerhans cells and lymphocyte infiltration. In addition to a DR and DQ positivity at the surface of the cells of the inflammatory infiltrate, a strong reaction for DR antigens was detected on keratinocytes. Hyperplasia of Langerhans cells was present in al cutaneous lesions and epidermis was infiltrated by T lymphocytes. When healed lesions of 14 of these subjects were re-biopsied 1 to 12 months after the end of pentavalent antimonial therapy, MHC class antigens could no longer be seen on keratinocytes. Our data represrn evidence for hhe reversibility of the abnormal HLA-DR expression by keratinocytes in ACL after Glucantime therapy or spontaneous scar formation, demonstrating that this expresion is restricted to the period of active lesions. The present findings can be regarded as an indirect evidence that keratinocytes may be involved in the immunopathology of ACL.

Potential sources of biodynamically active natural products in Brazil

In contrast to China where vegatation is predominantly herbaceous, vegetation in Brazil is commonly arboreous. This fact may explain why Chinese drugs are usually acetate derived, while actual and potential natural therapeutic agents from Brazil are mostly shikimate derived. Only relatively few compounds isolated from Brazilian plants have been submitted to adequate pharmacological testing

Marine organisms: an alternative source of potentially valuable natural products

This paper recalls the outcoming of marine natural products research and reviews a selection of marirne bioactive metabolites in current use together with promising trends in marine pharmacology.

Development of natural products as drugs acting on central nervous system

We have recenty studied several natural product constituents which have effects on the CNS. (1) Tetrahydropalmatine (THP) and its analogues were isolated from Corydalis ambigua and various species of Stephania. (+)-THP and (-)-THP posses not only analgesic activity, but also exert sedative-tranquillizing and hypnotic actions. Results of receptor binding assay and their pre-and post-synaptic effects on dopaminergic system indicate that (-)-THP and (-)-stepholidine are dopamine receptor antagonists while (+)-THP is a selective dopamine depletor. (2) 3-Acetylaconitine (AAC) is an alkaloid isolated from Aconitum flavum. The relative potency of analgesic action of AAC was 5.1-35.6 and 1250-3912 times that of morphine and aspirin, respectively. The analgesic effect of AAC was antagonized by naloxone, but was eliminated by reserpine. In monkeys, after AAC was injected for 92 days, no abstinence syndrome was seen after sudden AAC withdrawal or when challenged with nalorphine. (3) Huperzine A (Hup-A) is an alkaloid isolated from Huperzia serrata which was found to be a selective ChE inhibitor and could improve learning and retrieval process. Preliminary clinical studies showed that Hup-A improve short-and long-term memory in patients of cerebral arteriosclerosis with memory impairment. (4) Ranamargarin is a new tetradecapeptide isolated from the skin of the Chines frog Rana margaratae. This peptide may mainly act on NK-1 receptor.

Antimalarial chemotherapy with natural products and chemically defined molecules

In the present work we have described the in vivo antimalarial actrivity of six different plants. Two of them (Verninia brasiliana and Eupatorium squalidum) were tested in a randomic approach among 273 crude extracts from plants; four (Acanhospermum australe, Esenbeckia febrifuga, Lisianthus specious and Tachia guianensis) were selected after screening 22 crude extracts from different medicinal and some of them showed antimalarial activity in vitro. Some aspects of recent research with natural products aiming to produce drugs are discussed.

Evaluation of acute administration of natural products with potential diuretic effects, in humans

In order to evaluate the potential diuretic effect of two natural products, Elephantopus scaber and Alpinia speciosa, a trial administration was carried out in ten healthy volunteers and the effects compared to the those of a placebo. The substances were given on different days, with a seven day interval between doses. The amount of substance administered to the subjects was five times the usual dose i.e. 7.5 g/100 ml and 0.8 g/100 ml respectively. The following parameters parameteres were measured: urinary and plasma sodium, potassium, uric acid, calcium, phosphate, urea, creatinine. The subjects were also examined clinically and total urinary volume was assessed. The only significant finding (p < 0.05) was a slight diuresis with Alpinia speciosa, which also lowered the diastolic (p < 0.05) and systolic (p < 0.01) blood pressures. No effect on electrolytes or renal function parameters was observed, and this probably excludes any renal tubular or glomerular effect from these substances.

Ovipositional substrates used by Calyptrate Diptera in Tijuca forest, Rio de Janeiro

Twenty seven species of calyptrate muscoids were reared from a forested area of Rio de Janeiro (Tijuca Forest). Substrates for obtaining flies were beef liver, fish, mouse, frog, shrimp, snail carcasses, human faeces, banana and papaya fruits. The most frequent species found were: Fannia sp. (subgroup pusio) (49.9% on shrimp). Hemilucilia flavifacies (95.0% on liver). Phaenicia eximia (49.4% on mouse), Synthesiomyia nudiseta ( 100.0% on fish), Ophyra aenescens (100.0% on shrimp), Oxyvinia excisa (100.0% on faeces), Euboettecheria collusor (52.4% on faeces) and Pattonella intermutans (61.0% on frog).

Forest culicinae mosquitoes in the environs of samuel hydroeletric plant, state of Rondônia, Brazil

Data on frequency and seasonal distribution of culicinae were recorded in the forest near a recently constructed hydroelectric plant - Samuel, in the State of Rondônia, Brazilian Amazon. Collections were performed almost daily from August 1990 to July 1991, between 6 and 9 p.m., using human bait. A total of 3,769 mosquitoes was collected, representing 21 species, including seven new records for the State of Rondônia. The most frequently collected species were Aedes fulvus (25%) and Ae. pennai (12.3%). The highest density for the majority of mosquito species coincided with the rainy season.

Simian malaria at two sites in the Brazilian Amazon - II: Vertical distribution and frequency of anopheline species inside and outside the forest

An anopheline survey was carried out in two simian malaria areas in the Brazilian Amazon, Balbina and Samuel, to determine the potential vectors of Plasmodium brasilianum. The most abundant and/or acrodendrophilic anophelines in the forest and the most likely vector were Anopheles mediopunctatus, An. nuneztovari, An. oswaldoi, An. triannulatus and An. shannoni. An. darlingi and An. marajoara were captured essentially in anthropic habitats outside the forest and are unlikely to be involved in the transmission of P. brasilianum among monkeys within the forests and from monkeys to man in their surroundings in the Amazon.

Molecular Epidemiology of Human Polyomavirus JC in the Biaka Pygmies and Bantu of Central Africa

Polyomavirus JC (JCV) is ubiquitous in humans and causes a chronic demyelinating disease of the central nervous system , progressive multifocal leukoencephalopathy which is common in AIDS. JCV is excreted in urine of 30-70% of adults worldwide. Based on sequence analysis of JCV complete genomes or fragments thereof, JCV can be classified into geographically derived genotypes. Types 1 and 2 are of European and Asian origin respectively while Types 3 and 6 are African in origin. Type 4, a possible recombinant of European and African genotypes (1 and 3) is common in the USA. To delineate the JCV genotypes in an aboriginal African population, random urine samples were collected from the Biaka Pygmies and Bantu from the Central African Republic. There were 43 males and 25 females aged 4-55 years, with an average age of 26 years. After PCR amplification of JCV in urine, products were directly cycle sequenced. Five of 23 Pygmy adults (22%) and four of 20 Bantu adults (20%) were positive for JC viruria. DNA sequence analysis revealed JCV Type 3 (two), Type 6 (two) and one Type 1 variant in Biaka Pygmies. All the Bantu strains were Type 6. Type 3 and 6 strains of JCV are the predominant strains in central Africa. The presence of multiple subtypes of JCV in Biaka Pygmies may be a result of extensive interactions of Pygmies with their African tribal neighbors during their itinerant movements in the equatorial forest.

Distribution of Sandflies (Diptera:Psychodidae) on Tree-trunks in a Non-flooded Area of the Ducke Forest Reserve, Manaus, AM, Brazil

Sandflies were collected in the base of tree-trunks in the seasons of high and least rainfall in the Ducke Forest Reserve, near Manaus in the State of Amazonas. Lutzomyia umbratilis was the most abundant sandfly species. Caryocar villosum, Chrysophyllum amazonicum, Dinizia excelsa, Eschweilera atropetiolata and Parkia multijuga were the tree species on which most sandflies were collected and relative abundance were related to trunk characteristics. Seasonal patterns of sandfly distribution in the forest were observed.

A Mitochondrial DNA Phylogeny Indicates Close Relationships between Populations of Lutzomyia whitmani (Diptera: Psychodidae, Phlebotominae) from the Rain-forest Regions of Amazônia and Northeast Brazil

Phylogenetic analysis of all 31 described mitochondrial (cytochrome b) haplotypes of Lutzomyia whitmani demonstrated that new material from the State of Rondônia, in southwest Amazônia, forms a clade within a lineage found only in the rain-forest regions of Brazil. This rain-forest lineage also contains two other clades of haplotypes, one from eastern Amazônia and one from the Atlantic forest zone of northeast Brazil (including the type locality of the species in Ilhéus, State of Bahia). These findings do not favour recognizing two allopatric cryptic species of L. whitmani, one associated with the silvatic transmission of Leishmania shawi in southeast Amazônia and the other with the peridomestic transmission of Le. braziliensis in northeast Brazil. Instead, they suggest that there is (or has been in the recent past) a continuum of inter-breeding populations of L. whitmani in the rain-forest regions of Brazil.