Biomedical subjects

M T Perra

Publications and source records attributed to M T Perra.

At least 19 recordsLinked to original sources

PubMed2006

Finding of conjunctival melanocytic pigmented lesions within pterygium.

AIMS: Conjunctival pigmented lesions have characteristic clinical and histopathological appearances. Melanocytic pigmented lesions commonly occur in the conjunctiva, although they have not been previously reported in pterygium, a common lesion which originates from conjunctiva. Our aim was to evaluate the possibility of an association between pterygium and conjunctival melanocytic pigmented lesions. METHODS AND RESULTS: A total of 80 samples of pterygium excised from Ecuadorian patients in 2002 were collected. Clinical data were available regarding age, sex, race and place of residence. Histological sections were evaluated for the presence of melanocytic pigmented lesions. Nine cases of conjunctival melanocytic, pigmented lesions within pterygium were found and were classified according to the histopathological criteria previously published for pigmented lesions of the conjunctiva, as naevi and primary acquired melanosis (PAM) with varying degrees of atypia. Five of the nine cases showed primary acquired melanosis without atypia, while two cases had atypia; one case showed features of compound naevus and one lesion was designated as subepithelial naevus. CONCLUSIONS: Our findings suggest that conjunctival melanocytic, pigmented lesions occasionally occur in pterygium. All surgically removed pterygia should undergo careful histopathological examination.

Adolescent↗

PubMed2003

Detection of human papillomavirus DNA in pterygia from different geographical regions.

BACKGROUND/AIMS: The aetiology and pathogenesis of pterygia remain unclear and the involvement of human papillomavirus (HPV) is controversial. 41 pterygia from two geographic locations were evaluated for the presence of HPV DNA. METHODS: 41 pterygium biopsies (17 from Italy and 24 from Ecuador) were analysed using the L1C1 and PU-1ML primer sets by polymerase chain reaction (PCR) and DNA sequence analysis. RESULTS: 22 of the 41 pterygia (54%) were positive for HPV, including all 17 Italian cases and 5/24 (21%) Ecuadorean cases. DNA sequencing of the 22 positive cases showed that 11 were HPV type 52, four were type 54, five were candHPV90, and two of unknown genotype. CONCLUSIONS: The major differences in the frequency of HPV in geographically distant populations might suggest a possible explanation for the vast differences in the reported detection rates. Three subtypes of HPV were found in this sample of pterygia. None the less, these results suggest that HPV may have a pathogenic role in pterygium.

Biopsy↗

PubMed2002

Immunohistochemical study of human pterygium.

The purpose of this study has been to evaluate the immunohistochemical characteristics of human pterygial tissues in order to ascertain the possible contribution of an immunological mechanism in the pathogenesis of pterygium and to investigate the presence in the pterygial tissues of some melanoma-associated antigens, in order to evaluate if there may be a small possibility of correlation of the two diseases. Human biopsy specimens of pterygium were obtained by surgery for pterygium excision. Tissue segments were fixed and processed for paraffin embedding. Microtome sections were treated for the immunohistochemical demonstration of IgA, IgM, IgG, CD3, CD20, CD68, HLA-DR, Protein S100, HMB45, and Melan A using the avidin-biotin peroxidase method or the streptavidin biotin-alkaline phosphatase method. The findings suggest that all the effector components of the mucosal immune system are present in the human pterygium and, among the most sensitive markers for melanoma, only S100 shows immunoreactivity. An immunopathogenetic mechanism seems to be responsible for the pathogenesis of pterygium, perhaps being caused by pre-existing conjunctivitis or microtrauma in combination with the patient's predisposition. No correlation between pterygium and melanoma was found.

Adult↗

PubMed2000

Subcellular localization of epidermal growth factor in human submandibular gland.

Epidermal growth factor in human submandibular gland was localized at the subcellular level by means of an immunogold staining method. Labelling was observed in serous acini and ducts. In the acini, gold particles were found within secretory granules, indicating that the growth factor is released into the saliva through granule exocytosis. In the ductal system, the most intense reactivity was revealed in the principal cells of striated ducts. In these cells, an abundant population of small cytoplasmic vesicles was specifically stained. Immunoreactive vesicles were found both apically and basally, suggesting that ductal cells can release their products not only into the saliva but also into the interstitium.

Adolescent↗

PubMed2000

The presence of a local immune system in the upper blind and lower part of the human nasolacrimal duct.

The nasolacrimal duct is exposed to exogenous agents, including potentially harmful microorganisms, coming from the eye surface by the lacrimal sac, and from the nasal cavity by the inferior meatus of the nose. The upper blind and lower part of the human nasolacrimal duct were examined immunohistochemically to ascertain the presence and localization of immunoglobulin-producing cells and the epithelial expression of IgA, IgM, and IgG in order to verify the possible antimicrobial properties of this duct. IgA-, IgM-, and IgG-positive immunocompetent cells were recognizable in the lamina propria of the upper blind and lower part of the human nasolacrimal duct, while an evident immunoreactivity for sIgA, IgM, and IgG was demonstrated in the cytoplasm of the apical epithelial cells. The results suggest that all the effector components of the mucosal immune system are present in that area of the human nasal mucosa next to the opening of the nasolacrimal duct as well as in the human lacrimal sac.

Adolescent↗

PubMed1998

Immunohistochemical localization of secretory immunoglobulins in the main excretory duct of the human submandibular gland.

The localization of IgA, IgG, and IgM was investigated immunohistochemically in the mucosal surface of the main excretory duct of the human submandibular gland in order to verify the possible antimicrobial properties of this duct. Only secretory IgA-immunoreactivity was recognized in the epithelial cells of the duct. An intense immunoreactivity was observed in the cytoplasm of some cells and at the luminal surface of most of the cells. Clusters of IgA-positive immuno-competent cells were also recognizable in the subepithelial layers. No reactivity for IgG and IgM was noticed. The results suggest that the ductal epithelium may actively be involved in the release of secretory IgA, which could play a prominent role in the local defense mechanism of the duct.

Adult↗

PubMed1998

Immunoglobulins in the human male genitourinary tract.

Human male genitourinary tract was processed for the immunohistochemical demonstration of IgG and IgM, in order to verify the presence and the source of these immunoglobulins. Only the epithelia of the prostate gland and urethra showed a marked IgM-immunopositivity, localized in the cytoplasm of apical cells. An intense immunoreactivity for IgG was observed in the apical cells of the vesical epithelium; a less intense immunoreactivity for IgG in the pelvic apical epithelial cells was found. Immunostaining in the ureteric epithelium was absent. Clusters of IgM- and IgG-positive immunocompetent cells were present in the subepithelial layers of the organs observed in our study. This study indicates that IgM, present in mucosal surfaces, derived from an active secretion, as well as secretory IgA, whereas most of the IgG present in the human seminal plasma were probably due to transudation process. Immunoreactivity for IgG in the vesical and pelvic epithelia could depend upon to virus-specific IgG antibodies produced by the mucosa. This in turn can contribute to the total antiviral activity in mucosal secretions.

Adult↗

PubMed1997

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.

Adolescent↗

PubMed1996

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.

Acetylcholinesterase↗

PubMed1995

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.

Adult↗

PubMed1995

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.

Adult↗

PubMed1995

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.

Adult↗

PubMed1993

Peptidergic (VIP) nerves in normal human pancreas and in pancreatitis: an immunohistochemical study.

Vasoactive intestinal polypeptide was demonstrated in the nerves of the human normal pancreas and in pancreatitis by light microscope immunohistochemical technique. In specimens of normal pancreas, vasoactive intestinal polypeptide-immunoreactive neuronal cells were present in the autonomic ganglia. These ganglia were found to receive an abundant supply of vasoactive intestinal polypeptide-positive fibre plexuses. Immunoreactive nerve fibres were seen to run in the stroma, in association with secretory acini, ducts and blood vessels. Vasoactive intestinal polypeptide-positive fibres were also seen close to the Langerhans' islets, but no vasoactive intestinal polypeptide-like immunoreactivity was observed in the endocrine cells. In specimens from patients affected by pancreatitis, even in lesioned regions, immunoreactive elements were extremely scarce.

Connective Tissue↗

PubMed1990

L-leucyl beta-naphtylamidase activity and differentiation of adult human prostate.

The histochemical method for the demonstration of the L-leucyl-beta-naphtylamidase (LNAase) activity has been applied to bioptic and autoptic human prostates from very early to adult age to evaluate any correlation between sexual maturity and the appearance of this enzyme. The histochemical results indicate that in the human prostate, the LNAase activity is present at a cellular level in intrauterine life, infancy, and adulthood. This suggests that the appearance of this enzyme is genetically controlled even if different hormonal stimuli play some role in its localization and distribution.

Adult↗

PubMed1990

Human meibomian glands: a histochemical study for androgen metabolic enzymes.

Human meibomian glands were treated for the histochemical demonstration of several enzymatic activities. The 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD), 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) and 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) appeared intensely reactive in the differentiating excretory cells, and weakly reactive in the basal cells and in the epithelial cells of the proximal portion of the ducts. The results indicate that meibomian glands can metabolize androgens by the reductive pathway, characteristic of target tissues. The finding of an intense reactivity for the enzymes glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) is also discussed.

Adolescent↗

PubMed1988

Evidence for the presence of substance P-like immunoreactivity in the human cerebellum.

Preliminary results on the localization of substance P-like immunoreactivity in the human cerebellum are presented. Cerebella from newborn and adult subjects were examined. While only sporadic positive fibres were detected in the adult tissue, the immunoreactive material appeared more abundant in the cerebella from newborn subjects. Varicose and non-varicose fibres and dot-like nerve terminals were present with different density in various regions. The paucity of immunoreactive perikarya suggests that most of the cerebellar substance P-like immunoreactive material has an extrinsic origin.

Aged↗

PubMed1988

A histochemical study of the main excretory duct of the human submandibular gland.

The duct was reacted histochemically to identify glycoproteins and several enzymic activities. Neutral mucosubstances were detected in the entire cytoplasm of the principal cells, and acid glycoproteins were identified only in a thin apical zone corresponding to the glycocalyx. Lysosomal enzymes were demonstrated as cytoplasmic granules, whereas endogenous peroxidase was diffusely distributed throughout the entire cytoplasm of the epithelial cells. 17 beta- and 3 beta-hydroxysteroid dehydrogenases and prostaglandin-synthetase reactivity were intense in all epithelial cells.

Adult↗

PubMed1988

Histochemistry of L-leucyl beta-naphtylamidase activity in genital tract of men.

The histochemical method to demonstrate L-leucyl-beta-naphtylamidase (LNAase) activity has been applied to biopsies of normal human ductus deferens, deferential ampulla, seminal vesicle, prostate, bulbourethral (Cowper's) gland, and cavernous urethra. An intensely positive reaction was observed in the secreting epithelia of prostate, Cowper's, and urethral (Littré's) glands. Not only the prostate but also the Cowper's and Littré's glands secrete some LNAase into the semen. A possible role of the seminal LNAase is discussed.

Adult↗