Histomorphologic evaluation of guinea pig skin and soft tissue after controlled tissue expansion

To evaluate the histologic changes attendant on tissue expansion in the guinea pig, self-inflating implants were placed in the dorsal subcutaneous space and the tissue response was sequentially studied at periods ranging from 1 to 18 weeks. Fixation artifacts have been minimized. The cellular response is relatively benign. The epidermis does not undergo thinning during expansion, although dermis and panniculus carnosus become significantly thinner. Atrophy of panniculus muscle is demonstrable. This study supports the hypothesis that tissue expansion results in a net gain of donor tissue.     

Insecticide barrier spraying for the control of sand fly vectors of cutaneous leishmaniasis in rural Guatemala

An initial evaluation of insecticide barrier spraying directed against sand fly vectors of cutaneous leishmaniasis was done in a nonclimax forested area with heavy undergrowth in Peten, Guatemala. A 100 m-wide swath of vegetation was sprayed once with a 1:3 mixture of cyfluthrin insecticide and a palm oil carrier using back-pack sprayers to simulate a central cantonment area in one site while another site remained as an untreated control. Prior to spraying and throughout 87 days post-treatment, sand fly populations were monitored at both sites with light traps set at ground and canopy levels at 50-m intervals radiating out from the centers of the cantonments, 150-m in the four cardinal directions. A total of 2,876 female sand flies were captured, representing 16 species. Three species, Brumptomyia galindoi, Lutzomyia panamensis, and Lu, ovallesi, comprised 70% of the total collection. The single insecticide barrier significantly reduced sand flies from reaching the cantonment area for more than 80 days, while sand fly populations outside the treated cantonment and in the untreated (control) cantonment remained high (52 sand flies in the treated cantonment versus 235 sand flies in the untreated cantonment).     

Development and evaluation of an ELISA using recombinant fusion protein to detect the presence of host antibody to equine arteritis virus

Over the past 12 years, the poxvirus vector technology has provided scientists with valuable reagents to achieve high-level expression of proteins, to address questions of structure-function relationship of specific polypeptides, to investigate the immunobiology of specific pathogens, and to develop recombinant vaccine candidates. It is this last role that has drawn enthusiasm from the medical community because of the potential this technology has to provide novel approaches for addressing urgent needs in human and veterinary medicine. From one perspective, the safety issues surrounding the use of vaccinia-based vaccine candidates have been addressed with the development of the NYVAC and ALVAC vectors. Evaluation of these novel poxvirus vectors are in progress to determine their potential impact on cancer and infectious disease.     

Some thoughts on tolerance

In 4 duodenal ulcer patients the morphology of parietal cells has been studied before and one year after proximal gastric vagotomy (PGV). The average basal gastric acid secretion of the 4 patients was reduced from 9.2 m.mol/h before to 0.9 m.mol/h one year after PGV (90% reduction). The reduction in acid secretion was not accompanied by changes in the morphology of the parietal cells. Light microscopical studies indicated that the average cell size was about the same before and one year after PGV. Electron micro scopical studies showed only negligible changes in the parietal cell ultrastructure.     

Monocyte-mediated lysis of acute myeloid leukemia cells in the presence of the bispecific antibody 251 x 22 (anti-CD33 x anti-CD64)

Immunotherapy using bispecific antibodies (BsAb) to direct immune effector cells toward target tumor cells has been shown to be effective in a number of studies. Several immune trigger molecules have been characterized. Among them, FcgammaRI appears to play an important role in antibody-dependent cellular cytotoxicity. It is expressed mainly on monocytes, macrophages, and neutrophils under certain clinical situations. The expression of FcgammaRI can be regulated by a variety of cytokines, primarily by IFN-gamma. Recent studies have shown that granulocyte-colony-stimulating factor (G-CSF) and granulocyte-macrophage-colony stimulating factor (GM-CSF) can increase the number of the FcgammaRI-positive monocytes, increase the expression of FcgammaRI on circulating neutrophils after in vivo infusion, and greatly enhance the cytotoxic activity of circulating neutrophils. CD33 is a glycoprotein expressed on the cell surface of mature monocytes, myeloid progenitor cells, and myeloid leukemic blasts, but not on the earliest hematopoietic progenitor cells and other normal tissues. Herein, we report the construction of a BsAb, 251 x 22, by conjugating an anti-CD33 mAb (mAb 251) to an anti-FcgammaRI mAb (mAb 22). The BsAb 251 x 22 is capable of enhancing the cytotoxicity of several leukemia cell lines by cytokine-activated monocytes. Our data also show that G-CSF- and GM-CSF-stimulated monocytes can mediate cytotoxicity of target leukemia cells comparable to that of IFN-gamma-stimulated monocytes. The expression of FcgammaRI on monocytes after 24-h in vitro incubation with G-CSF and GM-CSF was increased, although not significantly. Prolonged incubation of monocytes with G-CSF for 48 h significantly increased the FcgammaRI expression. Because humanized anti-CD33 and anti-FcgammaRI mAb are available, and because GM-CSF and G-CSF have been used widely for patients after chemotherapy to stimulate the recovery of myeloid hematopoiesis, additional clinical development of this project is feasible. A BsAb comprised of humanized anti-CD33 and anti-FcgammaRI could have clinical application in the treatment of myeloid leukemia, especially in the management of minimal residual disease.     

Comparison of immunoaffinity chromatography enrichment and nuclease P1 procedures for 32P-postlabelling analysis of PAH-DNA adducts

32P-postlabelling analysis for detecting DNA adducts formed by polycyclic aromatic compounds is one of the most widely used techniques for assessing genotoxicity associated with these compounds. In cases where the formation of adducts is extremely low, a crucial step in the analysis is an enrichment procedure for adducts prior to the radiolabelling step. The nuclease P1 enhancement procedure is the most established and frequently used of these methods. An immunoaffinity procedure developed for class specific recognition for polycyclic aromatic hydrocarbon (PAH)-DNA adducts has therefore been compared with the nuclease P1 method for a range of DNA adducts formed by PAHs. The evaluation was carried out with skin DNA from mice treated topically with benzo[a]pyrene, 7,12-dimethylbenz[a]anthracene, 5-methylchrysene or chrysene. The immobilised antibody had the highest affinity for adducts structurally similar to the BPDE-I-deoxyguanosine adduct ([+/-]-N2-(7r,8t,9r-trihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene-1 0t-yl)-2'-deoxyguanosine) against which the antibody had been raised. Of the PAH-modified DNAs evaluated, the maximum adduct recovery was obtained for DNA containing the BPDE I-deoxyguanosine adduct. With DMBA-modified DNA, the profiles of adducts recovered from the column were similar when the column material was treated either with a digest of DMBA-modified DNA or with 32P-labelled DMBA adducts. I-compounds (endogenous adducts in tissue DNA of unexposed animals), which had similar chromatographic properties to PAH-DNA adducts, were not enriched by the immunoaffinity procedure. Compared to the simple nuclease P1 enhancement procedure, the immunoaffinity methods were lengthier and more labour intensive. Advantages of the immunoaffinity procedure include: specificity, allowing the selective detection of a certain class of adducts: efficient adduct enrichment, providing a viable alternative to other enrichment procedures; adequate sensitivity for model studies and the potential to purify adducts for further characterisation. However, as a general screen for detecting the formation of DNA adducts, the nuclease P1 procedure was viewed as the initial method of choice since it was capable of detecting a wider range of PAH-DNA adducts.