Normal colon of Sprague-Dawley rats

Summary The patterns of expression of the human-tumor-associated antigens, CO17-1A, GA73-3, BR55-2, GICA19-9, CA50 and carcino-embryonic antigen (CEA) were studied in the normal colonic mucosa (the last three also in the serum) of Sprague-Dawley rats. Four immunohistochemically different segments were identified: caecum, ascending colon, transverse colon and descending colon. The immunohistochemical reactions of the cells at the lower part of the crypt were essential for the distinction of the four segments. In the caecum, the MAbs 17-1A, 73-3 and 19-9 stained the glycocalyx of the cells of the lower part of the crypts and the Golgi apparatus of the intercalated cells (IC). MAb55-2 stained very weakly the goblet-like cells (GLC) of the lower part of the crypt of transverse colon, in addition to a nearly complete lack of reaction in the upper part of the crypts. In the ascending colon, the lower part of the crypts showed a characteristic diffuse staining of the intercalated cells with MAb55-2. The perinuclear and mucosal staining observed in the GLC of the transverse colon with MAbs 17-1A, 73-3 and 19-9 as against the supranuclear and Golgi zone staining observed in the GLC/goblet cells (GC)/columnar cells (CC) of the lower part of crypts of the descending colon with the same MAbs, distinguished the former segment from the latter. The IC demonstrated by immunohistochemistry in the lower parts of the crypts of caecum and ascending colon appear to correspond to the replicating cells of the colonic crypts.     

Malaria vectors in the Bioko Island (Equatorial Guinea): estimation of vector dynamics and transmission intensities

The current study was performed on the Bioko Island (Equatorial Guinea) with the aim of establishing a rapid assessment technique for mapping malaria risk and measuring vector densities. Human bait collection, tent traps, light traps, indoor resting collection, and window exit traps were used to collect Anopheles gambiae s.s. and Anopheles funestus, the two anopheline species involved in malaria transmission in this island. Capture data were used to compare differences in the behavior and vectorial capacity of An. gambiae s.s. and An. funestus. Differences in the two species of mosquitoes were found in relation to the season and trapping methods used. Entomological inoculation rates (EIR) for Plasmodium falciparum were calculated using a polymerase chain reaction (PCR) test with individual anopheline mosquitoes from human bait collections in two villages during the dry and rainy seasons. P. falciparum sporozoites were detected from both dissected heads/thorax and abdomens of both species.     

Genetic relatedness and antimicrobial resistance determinants among clinical isolates of enterococci from Cuba

This study describes the genetic relationships and antimicrobial resistance determinants found among 99 clinical isolates of enterococci from 15 different hospitals in Cuba. Pulsed-field gel electrophoresis SmaI analysis demonstrated a high degree of genetic diversity. A limited number of multiresistant Enterococcus faecalis clones, showing resistance to three or more families of antimicrobial agents, were detected simultaneously in different institutions, suggesting inter-hospital circulation of selected clones, and/or selection of particular clones following their introduction into the hospital environment. Antimicrobial resistance determinants, including erm(B), aac(6')-aph(2'), aph(3'), ant(6), vanB (E. faecalis) and vanA (Enterococcus faecium) were detected by PCR in various isolates.     

Rapid detection of cucumber vein yellowing virus by tissue-print hybridisation with digoxigenin-labelled cDNA probes

Hybridisation of tissue prints with nonradioactive cDNA probes was developed to detect cucumber vein yellowing virus (CVYV) in cucurbit plants. Results showed irregular distribution of the virus within cucumber, zucchini or melon plants without defined tropism for a specific tissue. Therefore, reliable diagnosis of CVYV requires analysis of tissue prints from at least five different plant sites. This detection procedure allows rapid analysis of large numbers of plants and it can be useful for epidemiological studies of CVYV and to control virus spread via eradication of early foci.     

Differentiation between Trichophyton mentagrophytes and T. rubrum by sorbitol assimilation.

Trichophyton rubrum was easily differentiated from T. mentagrophytes by its ability to assimilate sorbitol with an API 20C AUX strip. One hundred percent of 36 T. rubrum strains and none of 147 T. mentagrophytes strains assimilated sorbitol.     

ICAM-3, the third LFA-1 counterreceptor,is a co-stimulatory molecule for both resting and activated T lymphocytes

Optimal activation of human T cells mediated by ligation of CD3/T cell receptor (TcR) complex requires co-stimulatory signals. These can be provided by the adhesive interaction between receptor molecules on T cells and their counter-receptors on antigen-presenting cells. Soluble ICAM-3, anti-ICAM-3 and anti-CD3 mAb were utilized to address the role of the ICAM-3/LFA-1 pathway in TcR/CD3-dependent or -independent T cell activation. Immunoaffinity-purified ICAM-3 co-immobilized with suboptimal concentrations of anti-CD3 monoclonal antibody (mAb) stimulated T lymphocytes as monitored by the expression of the lymphocyte activation antigens CD25 and CD69. The mechanism underlaying this activation appear to involve the interaction of ICAM-3 with a β2 integrin, likely to be LFA-1, since mAb to the CD18 chain completely inhibited T cell activation. Similar experiments demonstrated that anti-ICAM-3 mAb were able to co-stimulate both resting (cord blood) and activated (T cell clones) T lymphocytes. On the contrary, anti-ICAM-1 mAb were only co-stimulatory for CD25 expression on activated but not on resting T cells. In addition, we have found that some γδ T cell clones bearing the Vδ1 segment were activated by direct mAb engagement of ICAM-3 in the absence of TcR/CD3 occupancy. Furthermore, immobilized anti-ICAM-3 mAb also induced development of dentritic processes. In conclusion, our data suggest that ICAM-3 on the surface of both T cells and antigen-presenting cells plays an essential role in the initiation of the immune response.     

Five types of pyloric cells in the antral mucosa of the stomach.

Only one type of pyloric cells in the exocrine antral glands is usually described in the literature. The review of 100 gastrectomy specimens revealed 5 types of pyloric cells: one composed of "ordinary" pyloric cells (i.e. cuboidal cells with ill-defined borders, pale, bubbly cytoplasm with an inconspicuous cytoplasmic network). The second type was characterized by pyloric cells with a small, regular vacuole, usually in a subnuclear position. The vacuole in such cells was negative for mucous stains. The third type of pyloric cells had a large intracytoplasmatic vacuole. Cells with this characteristic were found in cystically dilated pyloric glands. The vacuoles in such cells were usually negative for mucous stains although a rim of PAS or alcian blue positive substance was found in some vacuoles. The fourth type of pyloric cells had eosinophilic granules in the cytoplasm. These granules were proven to contain lysozyme. The fifth type had a non-vacuolated, homogeneous ("glassy") cytoplasm which was weakly positive for PAS but negative for acid mucins or mannosides. While the significance of the various types of pyloric cells herein described remains unclear, their easy identification in H & E stained preparations would permit more elaborated studies with histochemistry, immunohistochemistry and/or transmission electron microscopy in the future.