Bacteria in midguts of field-collected Anopheles albimanus block Plasmodium vivax sporogonic development

Bacterial infections were investigated in midguts of insectary and field-collected Anopheles albimanus Weidemann from southern Mexico. Serratia marcescens, Enterobacter cloacae and Enterobacter amnigenus 2, Enterobacter sp., and Serratia sp. were isolated in field samples obtained in 1998, but only Enterobacter sp. was recovered in field samples of 1997 and no bacteria were isolated from insectary specimens. These bacteria were offered along with Plasmodium vivax infected blood to aseptic insectary An. albimanus, and the number of infected mosquitoes as well as the oocyst densities assessed after 7d. Plasmodium vivax infections in mosquitoes co-infected with En. amnigenus 2, En. cloacae, and S. marcensces were 53, 17, and 210 times, respectively, lower than in control mosquitoes, and the mean oocyst density in mosquitoes co-infected with En. cloacae was 2.5 times lower than in controls. Mortality was 13 times higher in S. marcensces-infected mosquitoes compared with controls. The overall midgut bacterial infection in mosquito field populations may influence P. vivax transmission, and could contribute to explain the annual variations in malaria incidence observed in the area.     

Female fertility preservation before sterilizing treatment: contribution of ovarian tissue cryopreservation

Longer survival after anticancer treatment has lead to concern about the long-term adverse effects. Altered fertility is of particular importance. Before sterilizing treatment, three non-exclusive methods can be proposed to preserve female fertility: in vitro fertilization followed by cryopreservation of embryos, cryopreservation of mature ovocytes, cryopreservation of ovarian tissue. The method or methods chosen will depend on the age of the patient, here marital status, the urgency of the treatment, and the type of disease. Embryo cryopreservation is a routine practice in medically assisted reproduction centers, while cryopreservation of mature ovocytes and ovarian tissue is still in the experimental phase. It is known however that mature ovocytes can be used after cryopreservation. Cyropreservation of ovarian tissue is a more difficult problem. To date, there have not been any pregnancies or births after freezing-thawing of human ovarian tissue. This tissue could be used in two ways: autograft and in vitro folliculo-ovocyte maturation. Despite the uncertainty concerning use, women cryopreservation of ovarian tissue quite well.     

Relationships between cell division,expression of growth factors and microcirculation in the thyroids of Tg-A2aR transgenic mice and patients with Graves' disease

Tissue heterogeneity and nodule formation are hallmarks of thyroid growth. This is accounted for by the clonality theory that acknowledges different individual cellular abilities to respond to trophic stimuli. In order to test the hypothesis that functional and mitotic properties of thyrocytes could be influenced by paracrine interactions with neighbour endothelial cells, studies were conducted in both mouse and human goitre models. In the first part of the study, homogenous goitres in C57 black mice were compared with heterogeneous goitres in transgenic hyperthyroid mice expressing the A2 adenosine receptor (Tg-A2aR). The second part of the study concentrated on comparing human thyroid tIssue of control individuals and of patients with Graves' disease. The rate of cell division was evaluated by immunohistochemical detection of cells positive for proliferating cell nuclear antigen (PCNA). Their spatial distribution was then correlated with immunohistochemical cellular expression of growth- and vasoactive-related factors (fibroblast growth factor-2, transforming growth factor-beta, endothelin-1, vascular endothelial growth factor, nitric oxide synthase III), and with microcirculation expansion. Observations were made on digitalised images of histological serial sections. The nearest-neighbour method was used to distinguish between random or clustered distribution. PCNA-positive cells were both randomly and uniformly distributed in homogenous goitres from C57 black mice, and were clustered in tIssue areas identified as papillary and hyperplastic zones in heterogeneous goitres from Tg-A2aR mice. However, they were absent in the so-called compact cellular zones featuring resting cells. Moreover, whereas papillary and hyperplastic zones were highly vascularised, compact zones were nearly free of microvessels. Spatial distribution of dividing cells was positively correlated with the expression of growth-related factors. A similar pattern was observed in the thyroids of patients with Graves' disease. In accordance with the recent demonstration of the presence of angiofollicular units in the thyroid, these data strongly support the hypothesis that functional and mitotic properties of each single thyrocyte, likely to be responsible for growth heterogeneity of hyperplastic glands, may be adjusted at tIssue level by specific interactions with neighbour endothelial cells that, in turn, could alter the mitotic rate of thyrocytes through paracrine signals.     

Group B streptococcus cellulitis-adenitis syndrome in neonates. Is it a marker of bacteremia?

We report the case of an infant in whom facial cellulitis was the only initial sign of a group B streptococcal bacteriemia. Adenitis-cellulitis syndrome is a rare clinical manifestation of group B streptococcal infection in infants. Local infection together with the onset of fever can be the only signs of bacteriemia in newborns and infants.