Chromosomal localization of actin genes in the malaria mosquito Anopheles darlingi.

Physical and genetic maps have been used for chromosomal localization of genes in vectors of infectious diseases. The availability of polytene chromosomes in malaria mosquitoes provides a unique opportunity to precisely map genes of interest. We report the physical mapping of two actin genes on polytene chromosomes of the major malaria vector in the Amazon, Anopheles darlingi (Diptera: Culicidae). Clones with actin gene sequences were obtained from a cDNA library constructed from RNA isolated from adult females and males of An. darlingi. Each of the two clones was mapped to a unique site on chromosomal arm 2L in subdivisions 21A (clone pl05-A04) and 23B (clone pl17-G06). The obtained results, together with previous mapping data, provide a suitable basis for comparative genomics and for establishing chromosomal homologies among major malaria vectors.

Effects of strain and age on ear wound healing and regeneration in mice

Round holes in the ears of MRL mice tend to close with characteristics of regeneration believed to be absent in other mouse strains (e.g., C57BL/6). We evaluated the kinetics and the histopathology of ear wound closure in young (8 weeks old) C57BL/6 and BALB/c mice. We also used middle-aged (40 weeks old) C57BL/6 mice to evaluate the influence of aging on this process. A circular through-and-through hole was made in the ear, photographs were taken at different times after injury and wound area was measured with digital analysis software. The percentages of closed area measured on day 100 were: 23.57 ± 8.66 percent for young BALB/c mice, 56.47 ± 7.39 percent for young C57BL/6 mice, and 75.31 ± 23.65 percent for middle-aged C57BL/6 mice. Mice were sacrificed on days 1, 3, 5, 25, 44, and 100 for histological evaluation with hematoxylin and eosin, Gomori’s trichrome, periodic acid-Schiff, or picrosirius red staining. In young mice of both strains, healing included re-epithelialization, chondrogenesis, myogenesis, and collagen deposition. Young C57BL/6 and BALB/c mice differed in the organization of collagen fibers visualized using picrosirius-polarization. Sebaceous glands and hair follicles regenerated and chondrogenesis was greater in young C57BL/6 mice. In middle-aged C57BL/6 mice all aspects of regeneration were depressed. The characteristics of regeneration were present during ear wound healing in both young BALB/c and young C57BL/6 mice although they differed in intensity and pattern. Greater ear wound closure in middle-aged C57BL/6 mice was not correlated with regeneration.

Assessment of cell proliferation and prognostic factors in canine mammary gland tumors / Avaliação da proliferação celular e fatores prognósticos em tumores mamários caninos

Three methods for the analysis of cell proliferation, mitotic index/10 high-power fields (10 HPF), mitotic index/four sets of 10 HPF (40 HPF), and MIB-1 index were evaluated in a series of canine mammary gland tumors, as well as the possible correlation between them. Fifty-six canine mammary gland tumors, including 23 benign and 33 malignant, were studied. In addition, the prognostic impact of mitotic index/10 HPF, and histological malignancy grade were evaluated in 17 malignant tumors, being seven ductal and 10 metaplastic carcinomas. The three methods used to evaluate cell proliferation were correlated with the prognostic impact of mitotic index/10 HPF and histological malignancy grade. The results showed a strong association between mitotic figure counts and MIB-1 index (P<0.0001). A correlation was observed between mitotic count per 40 HPF and MIB-1, and between mitotic index per 10 HPF and 40 HPF (P<0.05). Moreover, histological malignancy grade and mitotic figure counts were excellent prognostic factors during three-year follow-up (P<0.05). There was a correlation between the three methods used for the evaluation of cell proliferation and prognostic factors as observed in human breast cancer studies.

Avaliaram-se três métodos de proliferação celular, índice mitótico/10 campos de grande aumento (10 CGA), quatro vezes 10 CGA (40 CGA) e índice de marcação por MIB-1, em uma série de tumores mamários caninos, e as possíveis correlações entre estes métodos. Foram estudados 56 tumores mamários caninos, 23 benignos e 33 malignos. Foi também avaliado o impacto prognóstico do índice mitótico (10 CGA) e o grau histológico maligno em 17 tumores malignos, sete carcinomas ductais e 10 carcinomas metaplásicos. A correlação entre os três métodos para avaliar a proliferação celular e o impacto prognóstico do índice mitótico por 10 CGA e o grau histológico maligno foi realizada. Os resultados mostraram que existe uma forte associação entre contagem de mitose e o índice de marcação por MIB-1(P<0,0001) e correlação entre contagem de mitoses em 40 CGA e índice de marcação por MIB-1 e entre índice mitótico em 10 CGA e 40 CGA (P<0,05). Observou-se correlação entre os três métodos de avaliação da proliferação celular e os fatores prognósticos semelhante aos estudos de câncer de mama humano.

Pathogenic aspects of pyogenic liver abscess associated with experimental schistosomiasis.

Schistosomiasis mansoni infection that occurs concurrently with Staphylococcus aureus bacteremia favors the formation of pyogenic liver abscess. The present experimental study in mice evaluated the following aspects of the relationship between infection with Schistosoma mansoni and liver abscess caused by S. aureus: a) the role of the eggs of S. mansoni in the genesis of the abscesses; b) the influence of different phases of schistosomiasis in the development of liver abscesses; and c) the effect of the treatment of schistosomiasis on the development of the abscesses. Macroscopic and histopathological study showed multiple liver abscesses around granulomas of S. mansoni in the acute and chronic phases of schistosomiasis. Treatment of acute schistosomiasis before experimentally-induced bacteremia did not prevent the formation of liver abscess. The study findings indicate that granulomas around S. mansoni eggs and worms lodged in the liver provide a focus and substrate for pyogenic abscesses caused by S. aureus.

Pyogenic liver abscesses and acute schistosomiasis mansoni: report on 3 cases and experimental study.

Three children with acute schistosomiasis mansoni developed pyogenic liver abscesses. The abscesses were diagnosed by ultrasonography and confirmed during laparotomy. Staphylococcus aureus were the sole bacteria isolated from the abscesses. An experimental study was carried out in mice to establish whether schistosomiasis is a predisposing cause for pyogenic liver abscesses. Seventeen mice (group 1) were infected with 40 Schistosoma mansoni cercariae (LE strain) and 60 d later inoculated intravenously with a strain of Staph. aureus, isolated from a patient with bacteraemia; 17 mice infected with Sch. mansoni (group 2), 19 infected with bacteria alone (group 3), and 18 uninfected mice (group 4), served as controls. Thirteen group 1 mice (77%) developed multiple liver abscesses while none was observed in the controls. These results indicate that acute schistosomiasis mansoni concurrent with Staph. aureus bacteraemia favours the colonization of the liver by bacteria and the development of pyogenic hepatic abscesses.