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Biomedical subjects

M D Martins

Publications and source records attributed to M D Martins.

14 recordsLinked to original sources
PubMed2007

Intraosseous schwannoma mimicking a periapical lesion on the adjacent tooth: case report.

AIM: To present an additional case of intraosseous schwannoma involving the apical area in the mandibular alveolar bone mimicking an inflammatory periapical lesion. SUMMARY: This article describes a case of schwannoma periapically located mimicking an inflammatory periapical lesion in the mandible of a 34-year-old female. Diagnostic and therapeutic problems can occur when this lesion is misinterpreted as being endodontic in origin. The diagnosis, radiograph, immunohistochemical aspects and treatment are also discussed. KEY LEARNING POINTS: Intraosseous schwannoma is a rare unilocular radiolucency that when located periapically could be misdiagnosed as an endodontic lesion and result in unnecessary root canal treatment. The vitality of the pulp is an important test to exclude lesions of inflammatory origin. Histological examination is important to establish the diagnosis of lesions in the periradicular region.

Adult↗
PubMed2006

Somatic cytogenetic and azoospermia factor gene microdeletion studies in infertile men.

The objective of the present study was to determine the frequency of somatic chromosomal anomalies and Y chromosomal microdeletions (azoospermia factor genes, AZF) in infertile males who seek assisted reproduction. These studies are very important because the assisted reproduction techniques (mainly intracytoplasmic sperm injection) bypass the natural selection process and some classical chromosomal abnormalities, microdeletions of AZF genes or some deleterious genic mutations could pass through generations. These genetic abnormalities can cause in the offspring of these patients male infertility, ambiguous external genitalia, mental retardation, and other birth defects. We studied 165 infertile men whose infertility was attributable to testicular problems (60 were azoospermic, 100 were oligospermic and 5 were asthenospermic). We studied 100 metaphases per patient with GTG banding obtained from temporary lymphocyte culture for chromosomal abnormality detection and performed a genomic DNA analysis using 28 Y chromosome-specific sequence-tagged sites for Y AZF microdeletion detection. Karyotyping revealed somatic anomalies in 16 subjects (16/165 = 9.6%). Of these 16, 12 were in the azoospermic group (12/60 = 20%) and 4 were in the oligospermic group (4/100 = 4%). The most common chromosomal anomaly was Klinefelter syndrome (10/165 = 6%). Microdeletions of AZF genes were detected in 12 subjects (12/160 = 7.5%). The frequencies detected are similar to those described previously. These results show the importance of genetic evaluation of infertile males prior to assisted reproduction. Such evaluation can lead to genetic counseling and, consequently, to primary and secondary prevention of mental retardation and birth defects.

Chromosome Deletion↗
PubMed2003

A study of the extracellular matrix in salivary gland tumors.

BACKGROUND: Epithelial-mesenchymal interactions constitute fundamental phenomena in the development and maintenance of the characteristic branching pattern seen in salivary glands. This study was undertaken to discuss the extracellular matrix (ECM) role in morphogenesis and cellular differentiation of salivary gland tumors originating from the intercalated duct. METHODS: The ECM components, laminin (LN), type IV collagen, fibronectin (FN), and tenascin (TN) were revealed using a streptoavidin-biotin immunohistochemical technique and analyzed in 34 cases of salivary gland tumors: pleomorphic adenoma (PA); myoepithelioma; basal cell adenoma (BCA); polymorphous low grade adenocarcinoma (PLGA); and adenoid cystic carcinoma (ACC). RESULTS: LN and type IV collagen were present in all tumors, confining well-organized duct-like structures, separating them from the stroma, or surrounding cell clusters. In PA and myoepithelioma, the basement membrane (BM) fragmentation was observed through LN and type IV collagen staining around each individual spindle-shaped cell, which was strictly related to the cell modification. Interestingly, BM interruption could not be seen in the malign tumors, however, was frequently augmented in some cases. LN, type IV collagen, and FN were also found in the stroma of all tumors studied, except for the pseudocystic spaces of ACC, which were only delimited by replicated LN and type IV collagen. TN exhibited a variable expression, being more intense in solid ACC. CONCLUSIONS: LN and type IV collagen were always present around morphologically well-differentiated duct-like structures in all tumors studied. BM interruption could not be seen in the malign tumors, on the contrary BM production was evident, which is probably related to invasion. FN was present in the stroma of all tumors, but TN was mostly observed in less differentiated and higher degree of malignancy tumors, such as solid ACC.

Adenocarcinoma↗
PubMed2003

Immunolocalization of bone extracellular matrix proteins (type I collagen, osteonectin and bone sialoprotein) in human dental pulp and cultured pulp cells.

AIM: To simultaneously analyse the expression of type I collagen, osteonectin and bone sialoprotein (BSP) in human dental pulp of different ages. METHODOLOGY: Cultured dental pulp fibroblasts (FP1 cell line), pulps from dental germs with incomplete root formation (n = 4) and pulps of erupted teeth with total root formation (n = 4) were used. Bone proteins were searched by immunohistochemistry and immunofluorescence using polyclonal antibodies and compared among the three groups assessed. RESULTS: Immunohistochemistry detected the three proteins in dental pulp tissue, as it labelled extracellular matrix, predentine and odontoblasts. The BSP label was weaker, when compared to both type I collagen and osteonectin. The presence of type I collagen was more evident in pulps from erupted teeth, when compared to germ dental pulps. On the other hand, a strong expression of osteonectin in germ dental pulps was observed. CONCLUSIONS: Regardless of the degree of maturation, dental pulps present type I collagen, osteonectin and BSP in the extracellular matrix (ECM) and in the odontoblastic layer. Thus, the results suggest that these proteins are related to the production and mineralization of dentine.

Cell Line↗
PubMed2000

Mycoses in AIDS.

Major changes are occurring in the epidemiology of opportunistic infections (OI) in patients with acquired immune deficiency syndrome (AIDS) and treated with highly active antiretroviral therapy (HAART). A marked decrease of minor and major OI was observed and clinical resistance of thrush to antifungal agents became extremely rare. Primary and secondary prophylaxis against Pneumocystis carinii infections can be stopped; however, the situation is less clear for other OI such as cryptococcosis or endemic mycoses. The epidemiology is dramatically different in the countries which cannot afford the cost of HAART for the majority of patients, such as South Africa. These topics will be discussed in this paper.

AIDS-Related Opportunistic Infections↗
PubMed1998

Declining rates of oropharyngeal candidiasis and carriage of Candida albicans associated with trends toward reduced rates of carriage of fluconazole-resistant C. albicans in human immunodeficiency virus-infected patients.

In order to determine the current prevalence and incidence of fluconazole-resistant oropharyngeal candidiasis among human immunodeficiency virus (HIV)-infected patients, we conducted a prospective observational study of a consecutive series of HIV-infected patients. Of 128 enrolled patients, 70 patients completed four quarterly follow-up visits over a period of 1 year. Over this period, declining rates of carriage of Candida albicans (from 61% to 39%; P = .008) and of oropharyngeal candidiasis (from 30% to 4%; P < .001) were documented. Trends toward reduction in the frequency of fluconazole-resistant isolates (MIC, > or = 64 micrograms/mL) were also seen. During the survey period, the mean (median) number of antiretroviral agents used per patient rose from 0.5 (0) to 1.8 (2) (P < .001). Thus, rather than progression, we observed declining rates of oropharyngeal candidiasis, C. albicans carriage, and fluconazole-resistant C. albicans in a cohort of HIV-infected patients treated with increasingly effective antiretroviral therapy.

AIDS-Related Opportunistic Infections↗
PubMed1998

Activated lymphocytes reduce adherence of Aspergillus fumigatus.

Lymphocytes comprise up to 30% of the cells present in human bronchoalveolar lavage fluid and thus could participate in host response to infectious Aspergillus fumigatus conidia. We have examined the possibility that lymphocytes might play a role during early infection by either damaging the fungus or interfering with adherence. When incubated with A. fumigatus conidia for 20 h, highly purified 5-day-old lymphocytes activated with either IL-2 or phytohaemagglutinin, but not untreated lymphocytes, were consistently able to reduce residual fungal biomass as estimated by a metabolic assay. T lymphocytes, but not NK cells, appeared to be responsible for this activity. Lymphocytes bound both A. fumigatus conidia and hyphae, and the antifungal activity of the lymphocytes required direct lymphocyte fungus contact. In a separate set of experiments using release of 51Cr from 51Cr-loaded fungi as an estimate of fungal damage, lymphocyte-induced loss of fungal biomass was found to be due to loss of fungal adherence rather than to direct fungal damage. The detached hyphae were also found to be metabolically intact and to have normal morphology by electron microscopy. These data demonstrate that IL-2- and phytohaemagglutinin-activated lymphocytes exhibit a contact-dependent ability to reduce adherence of germinating conidia of A. fumigatus to a surface.

Aspergillus fumigatus↗
PubMed1997

Point prevalence of oropharyngeal carriage of fluconazole-resistant Candida in human immunodeficiency virus-infected patients.

To estimate the prevalence of both clinically evident and asymptomatic carriage of fluconazole-resistant Candida, we prospectively surveyed 128 adults infected with human immunodeficiency virus (HIV). The patients had an average CD4 cell count of 206/mm3. Ninety-seven isolates of Candida were obtained from the oropharynx of 82 patients (64%). Of these 82 patients, 76% carried C. albicans alone; 18%, both albicans and non-albicans isolates; and 6%, non-albicans species alone. Oropharyngeal candidiasis was evident in only 38 (46%) of the 82 patients for whom a culture was positive and was never seen unless C. albicans was present. When MICs were measured by using the National Committee for Clinical Laboratory Standards M27-T methodology and grouped by using recently proposed breakpoints, we found that eight of the 38 patients with oropharyngeal candidiasis and six of the 44 patients who were asymptomatically colonized carried C. albicans isolates resistant to fluconazole (MIC, > or = 64 micrograms/mL); estimated rates of carriage were 21% (95% confidence interval, 10%-37%) and 14% (95% confidence interval, 5%-27%), respectively. Carriage of resistant isolates of C. albicans by HIV-infected adults is more common than previously suspected, and clinicians should be alert to the possible need for either higher doses of fluconazole or alternative treatment modalities.

Adult↗
PubMed1996

Resistance to antifungal agents in the critical care setting: problems and perspectives.

As is the case with antibacterial agents, the increasing use of antifungal agents has led to development of antifungal resistance, the most clinically important of which is the resistance of Candida to fluconazole. While mutation to high-level fluconazole resistance is possible, the most important aspect of fluconazole resistance for patients in the ICU is the possibility of an epidemiologic shift away from such susceptible species as C. albicans and C. parapsilosis toward the most resistant species, such as C. glabrata and C. krusei. Resistance to amphotericin B by Candida is also possible, but less frequent. Strategies for treating invasive Candida infections must consider the relative rates of non-C. albicans Candida infection and the likelihood of antifungal resistance. The agents that cause invasive mold infections in the ICU are intrinsically moderately resistant to the available antifungal agents, and therapy depends less on the choice of antifungal therapy than on the correction of predisposing factors. The role of susceptibility testing as a guide in selecting appropriate therapy for all of these infections is as yet incompletely defined, but testing for resistance to fluconazole may soon be ready for clinical use.

Amphotericin B↗