Análise ultraestrutural do colágeno de feridas cutâneas de coelhos tratadas com plasma rico em plaquetas de equino / Ultrastructural analysis of the collagen of rabbit skin wounds treated with platelet-rich equine plasma

O colágeno é sintetizado e segregado no espaço extracelular e organizados em fibrilas estriadas de acordo com o tipo de tecido. Utilizaram-se 24 coelhos brancos da raça Nova Zelândia, com idade de 12 meses e com 3,0kg de peso corporal, para avaliar a porcentagem de colágeno das feridas cutâneas tratadas com plasma rico em plaquetas de equino e pomada contendo gentamicina, sulfanilamida, sulfadiazina, ureia e vitamina A. Os animais foram separados em quatro grupos de igual número e submetidos à remoção de pele na região das linhas médias dorsal torácica (feridas tratadas) e lombar (feridas controle). As feridas torácicas foram tratadas com plasma rico em plaqueta de equino e pomada contendo gentamicina, sulfanilamida, sulfadiazina, ureia e vitamina A, e as do grupo controle somente com a pomada. Dos animais do grupo I, foi coletado tecido cutâneo, para a avaliação histológica e a ultraestrutural, com três dias de pós-operatório; dos animais do grupo II, com sete dias; do grupo III, com 14 dias; e do grupo IV, com 21 dias. Decorrido o período de avaliação de cada grupo, foi coletado fragmento de pele para avaliação da porcentagem de colágeno, bem como do diâmetro e da densidade da fibrila de colágeno por microscopia eletrônica de transmissão. O tratamento com PRP de equino associado à aplicação tópica da pomada mostrou-se eficaz na maturação das fibrilas colágenas e na antecipação do processo cicatricial.(AU)

Collagen is synthesized and secreted into the extracellular space and organized into striated fibrils according to the tissue type. This study evaluated the concentration of collagen in rabbit skin wounds treated with equine platelet-rich plasma (PRP) and ointment containing gentamicin, sulfanilamide, sulfadiazine, urea, and vitamin A. Twenty-four New Zealand white rabbits aged 2 to 12 months and weighing 3.0kg were included. The animals were allocated equally into four groups and the skin was removed from the thoracic dorsal midline (treated wound) and lumbar (control wound) regions. The thoracic wounds were treated with equine PRP and ointment containing gentamicin, sulfanilamide, sulfadiazine, urea, and vitamin A, and the control group was treated with the ointment alone. For histological and ultrastructural assessment, cutaneous tissue was collected on postoperative days 3 (group I), 7 (group II), 14 (group III), and 21 (group IV). After the evaluation period, in each group, a skin fragment was collected for analysis of the collagen concentration, as well as the collagen fibril diameter and density by transmission electron microscopy. The results indicated that treatment with equine PRP combined with topical application of the ointment was effective in facilitating the maturation of collagen fibrils and the wound healing process.(AU)

Antimalarial and toxic effect of triple combination of pyronaridine, sulfadoxine and pyrimethamine.

The triple combination of pyronaridine, sulfadoxine and pyrimethamine which has been proven to be efficient in delaying emergence of drug resistance of rodent malarial parasites was further studied for potential application to malaria control. The antimalarial effect of the triple combination on Plasmodium berghei ANKA-infected mice and the toxic effects in mice and rats were additive. A single dose of pyronaridine 500 mg in combination with sulfadoxine, 1000 or 1500 mg, and pyrimethamine, 50 or 75 mg, given to 72 acute falciparum malaria patients resulted in a 100% cure rate with nil or mild side effects, and no recrudescence of asexual parasite over 4-week follow-up. Preliminary experiments on the drug effect on sporogony showed that the drug combination at the dose used could not completely interrupt the sporozoite formation although many retarded oocysts were found.

Comparative drug trial of a sulfadoxine/pyrimethamine and a sulfalene/pyrimethamine combination against Plasmodium falciparum infections in semi-immune populations of Burma.

The antiplasmodial effect of a single dose treatment with a sulfadoxine/pyrimethamine combination as compared to a sulfalene/pyrimethamine combination against falciparum malaria was assessed in semi-immune populations in Burma in early 1980. Parasite clearance rates on Day 7 after treatment were 99.2% for the sulfadoxine/pyrimethamine combination and 98.6% for the sulfalene/pyrimethamine combination for all age-groups. The earlier recrudescence rates within one month were 3.7% and 9.2% respectively, while the later recrudescence rates between 1 and 2 months were 9% and 8.3% respectively. Hence, both combinations were equally effective for treatment of falciparum malaria as no significant difference in the parasite clearance rates was observed. However, the earlier recrudescence rates showed a significant difference with a higher rate for the sulfalene/pyrimethamine combination. This is thought to be due to the shorter half-life of sulfalene compared to sulfadoxine and to its being unable therefore to suppress the falciparum infections for as long a period as sulfadoxine. But there was not much difference in the later recrudescence rates. These combinations have a stimulating effect on the production of falciparum gametocytes; and, in order to minimize transmission, an effective gametocytocide such as primaquine should be given along with them, as well as with the chloroquine/pyrimethamine combination, in areas with efficient malaria vectors. Recrudescence rates and gametocyte rates were highest among children in the 1-4 years age-group and this could be attributed to their lower level of acquired immunity compared to the older children and adults. Vivax malaria was also found to be effectively suppressed for about 4 weeks with both combinations.(ABSTRACT TRUNCATED AT 400 WORDS)