Local immune response in the skin of the external auditory meatus: an immunohistochemical study.

Cerumen plays an important role in the protection of the external auditory meatus against several kinds of damage. Its hydrophobic properties, due to the high concentration of lipids, shelter the canal from physical damages, while other components probably protect against certain microbial strains. Nevertheless there has been considerable dispute in the literature with regard to the antibacterial activity of cerumen. Because of the importance of the role of immunoglobulins (Ig) in local defense mechanisms, we attempted to study, by immunohistochemical methods, the presence and localization of the cells necessary to activate an Ig-mediated immune response and the epithelial expression of immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin G (IgG) in order to obtain information about a local immune response in those areas of the skin that take part in cerumen production. Our findings indicate that in the human skin of the external auditory canal the cells necessary to activate an antibody-mediated immune response were localized in the different layers of the epidermis and/or in the dermis surrounding the sebaceous and ceruminous glands and the piliary follicle, while an intense immunoreactivity for IgA and IgG was observed in the epithelial layers of the skin. The results suggest that the external auditory canal is protected from the insults of pathogens by an antibody-mediated local immune response, because all the effector components of an active local immune system are present.

Salvage chemotherapy with paclitaxel in platinum-resistant advanced ovarian cancer patients.

Encouraging results with Paclitaxel are reported in ovarian cancer patients relapsing and progressing after platinum-based chemotherapy; however, the two populations have different probabilities of a response to a second-line treatment. Here we report the results achieved in 39 patients with platinum-refractory ovarian cancer, treated with Paclitaxel 175 mg/qm2 (or 135 mg/m2 if heavily pretreated) using 3-hour intravenous infusion every 3 weeks, in an attempt to verify the activity of this drug in platinum-resistant patients. The toxicity was mild to moderate and primarily hematologic and neurologic. The objective response rate is 12.8% with no complete responses. The response duration was brief and the median survival 6 (range 1-17) months. An accurate cost-benefit balance is necessary before routinely use of Paclitaxel in platinum-refractory patients. Further research is needed to determine the optimal role of Paclitaxel in the whole therapeutic strategy for ovarian cancer.

Histochemical demonstration of acetylcholinesterase activity in human Meibomian glands.

The distribution of acetylcholinesterase activity in human Meibomian glands was evaluated using enzyme-histochemical methods. The butyrylcholinesterase (BuChE) inhibitor, tetraisopropyl pyrophosphoramide (iso-OMPA), was used to localize acetylcholinesterase (AChE) activity, the AChE inhibitor, 1,5-bis (4-allyldimethylammoniumphenyl) pentan-3-one dibromide (BW284c51), was used to localize BuChE activity, and eserine was used to inhibit all cholinesterase activity in control incubations; the appropriate specific inhibitors for competing enzymic activities were added to the incubation medium. At the light microscopic level, acetylcholinesterase reaction product appeared as cytoplasmic brown deposits, often crystalline. A very dense accumulation of AChE-positive nerve fibers was seen in the form of a network around the acinar and the ductal tissue of the glands. No discrete nerve endings were observed, whereas a strong reaction was elicited in some fibers in close association with blood vessels. These observations suggest that the cholinergic system is involved in the regulation of the Meibomian glands secretory function.

A histochemical and immunohistochemical study of certain defense mechanisms in the human lacrimal sac epithelium.

The mucosal surface of the human lacrimal sac represents an area exposed to exogenous agents including potentially harmful microorganisms. The human lacrimal sac was examined histochemically to identify glycoproteins, and immunohistochemically to identify secretory IgA. Neutral and acid glycoconjugates were detected mainly in the cytoplasm of the surface cells of the columnar stratified epithelial lining. The same reactions were recognized in occasional clusters of secretory cells forming intraepithelial glands in the lining of the lacrimal sac. The presence of secretory IgA in the cytoplasm of the apical epithelial cells was demonstrated. The results indicate that the lacrimal sac mucosa possesses certain active defense mechanisms against ascending infections.

Immunohistochemical study of secretory IgA in the human male reproductive tract.

Male human genital tract was treated for the immunohistochemical demonstration of secretory IgA in order to verify its own possible antimicrobial properties. An intensely positive immunoreaction for sIgA in the epithelial cells of prostate and urethral glands was observed; in the same organs the presence of immunoreactive cell clusters in the subepithelial layers was noted. Immunostaining in the epithelia of deferent duct, seminal vesicle, deferential ampulla, ejaculatory duct and bulbourethral glands was absent. The findings suggest that a local immune response sIgA-mediated is present in the lower male genital tract.

Immunohistochemical demonstration of secretory IgA in human urothelium.

The mucosal surface of the human urothelium represents a very large exposure area to exogenous agents, including potentially harmful microorganisms. Male human urothelium was treated for the immunohistochemical demonstration of secretory IgA (sIgA) in order to verify its own possible antimicrobial properties. An intense immunoreactivity for sIgA was observed in the apical cells of the urethral and vesical epithelia. The ureteric epithelium, at the luminal surface, showed discontinuous areas of less dense or completely absent reaction product. A less intense immunoreactivity was observed in the pelvic apical epithelial cells. The results suggest that sIgA play a prominent role in the local defence mechanisms of the lower urinary tract against ascending infections, whereas in the upper urinary tract the immuno-specific local defences seem reduced.

Human male genitourinary tract: an immunohistochemical study of secretory IgA.

Male human genitourinary tract was treated for the immunohistochemical demonstration of secretory IgA (sIgA) in order to verify its own possible antimicrobial properties. An intense immunoreactivity for sIgA was observed in the apical cells of the urethral and vesical epithelia. The ureteric epithelium, at the luminal surface, showed discontinuous areas of less dense or completely absent reaction product. A less intense immunoreactivity in the pelvic apical epithelial cells was found; an intensely positive immunoreaction for sIgA in the epithelial cells of prostate and urethral glands was also observed. The results suggest that a local immune response sIgA-mediated is present in the lower male urogenital tract.

Human urethral epithelium: immunohistochemical demonstration of secretory IgA.

Male human urethral epithelium was treated for the immunohistochemical demonstration of secretory IgA in order to verify its own possible antimicrobial properties. An intense immunoreactivity for sIgA in the entire cytoplasm and at the luminal surface of the apical epithelial cells was observed. The results suggest that sIgA play a prominent role in the local defense mechanisms of the urethra. Such mucosal defense mechanisms may be of significance in the defense of the urinary and genital tract against ascending infections.

Histochemical study of the human bulbourethral (Cowper's) glands.

Human bulbourethral glands were reacted histochemically and immunohistochemically to identify glycoproteins, some androgen metabolic enzymes, and VIP-like immunoreactivity. Neutral/acid mucosubstances were detected in the cytoplasm of the tubuloalveolar and ductal cells. 3 beta-, 17 beta-, and 3 alpha-hydroxysteroid dehydrogenase, G6PD, and 6PGD reactivity were intense in all the glandular epithelium. Small amounts of VIP-positive fibres were observed around the secretory elements.

Histochemistry of human urethral glands.

Human urethral glands were reacted histochemically and immunohistochemically to identify glycoproteins, some androgen metabolic enzymes, and VIP-like immunoreactivity. Neutral/acid mucosubstances were detected mainly in the apical cytoplasm of the principal cells. 3 beta-, 17 beta-, and 3 alpha-hydroxysteroid dehydrogenase, G6PD, and 6PGD reactivity were intense in all the glandular epithelium. Small amounts of VIP-positive fibers were noted around the secretory elements.