Biomedical subjects

R S Gomez

Publications and source records attributed to R S Gomez.

At least 19 recordsLinked to original sources

PubMed2007

The IL1A (-889) gene polymorphism is associated with chronic periodontal disease in a sample of Brazilian individuals.

BACKGROUND AND OBJECTIVE: It has been proposed that genotypes reflective of polymorphisms in cytokine genes can predispose individuals to disease by enhancing inflammatory processes. The C/T polymorphism at position -889 of the IL1A gene influences interleukin-1alpha expression, with the T allele inducing higher expression. The aim of this study was to evaluate the association of the IL1A (-889) gene polymorphism in Brazilian individuals with different clinical forms of periodontitis and severity of disease. MATERIAL AND METHODS: DNA was obtained from oral swabs of 163 Brazilian individuals and was amplified using the polymerase chain reaction (PCR). Products were submitted to digestion and were analyzed by electrophoresis to distinguish the C and T alleles. RESULTS: A significant difference in the genotype distribution was observed when comparing the chronic periodontitis group with the control group, evaluating only nonsmokers (chi-squared analysis = 9.91; p = 0.007), as well as when smokers were included (chi-squared analysis = 6.36; p = 0.04). Moreover, we observed a higher incidence of the T allele in the chronic periodontitis group (37.8%) when compared with the control group (18.4%) in nonsmokers (p = 0.006, odds ratio = 2.69, confidence interval = 1.27-5.68) and also when smokers were included (p = 0.03, odds ratio = 1.87, confidence interval = 0.98-3.56). No statistical difference was observed when the aggressive periodontitis group was compared with the control group. With regard to severity of disease, no statistical difference was observed. CONCLUSION: These data show an association of the IL1A (-889) polymorphism with chronic periodontitis in Brazilian individuals.

Adolescent↗

PubMed2006

Epidural anaesthesia as a complication of attempted brachial plexus blockade using the posterior approach.

We report a case of accidental epidural anaesthesia as a complication of attempted brachial plexus blockade using a posterior approach in a 31-year-old man scheduled to undergo elective shoulder surgery. The block was inserted with the patient in the lateral position before induction of general anaesthesia. On emergence from anaesthesia, the patient could breathe but could not move his arms. He had no pain sensation from the fifth cervical dermatome to the third thoracic dermatome bilaterally; this resolved 8 h after surgery and he was discharged well 2 days later. Although proponents of the posterior approach to the brachial plexus claim that its use is associated with a lower incidence of significant complications, this case proves that the technique is not devoid of potentially serious complications.

Acromion↗

PubMed2006

Association of interleukin-1beta polymorphism with recurrent aphthous stomatitis in Brazilian individuals.

BACKGROUND: Recurrent aphthous stomatitis (RAS) is characterized by recurrent episodes of oral ulceration in an otherwise healthy individual. Some reports in the literature indicate that RAS may have immunological, psychological, genetic and microbiological bases. The purpose of the present study was to investigate the possible association between interleukin-1beta (IL-1beta) +3954 (C/T) genetic polymorphism and RAS in a sample of Brazilian patients. SUBJECTS AND METHODS: Sixty-two consecutive subjects affected by minor and major forms of RAS and 62 healthy volunteers were genotyped at IL-1beta (+3954). The chi-squared test was used for statistical analysis. RESULTS: A significant increase in the high production of IL-1beta genotype CT was observed in the group with RAS (P = 0.01). After stratifying RAS patients according to the mean number of lesions per episode, a significant difference was only observed between patients with >or=3 lesions in each episode and control. CONCLUSION: There is an increased frequency of polymorphism associated with high IL-1beta production in RAS patients.

Adolescent↗

PubMed2005

Molecular and immunohistochemical investigation of protein kinase a regulatory subunit type 1A (PRKAR1A) in odontogenic myxomas.

Odontogenic myxomas are rare benign neoplasms affecting the jaw. Myxomas of bones and other sites occur as part of Carney complex (CNC), a multiple neoplasia syndrome caused by mutations in the PRKAR1A gene, which codes for the regulatory subunit of protein kinase A (PKA). In the present study, 17 odontogenic myxomas from patients without CNC were screened for PRKAR1A mutations and PRKAR1A protein expression by immunohistochemistry (IHC). Mutations of the coding region of the PRKAR1A gene were identified in 2 tumors; both these lesions showed no or significantly decreased immunostaining of PRKAR1A in the tumor compared to that in the surrounding normal tissue. One mutation (c.725C>A) led to a nonconservative amino acid substitution in a highly conserved area of the gene (A213D); the other was a single base-pair deletion that led to a frameshift (del774C) and a stop codon 11 amino acids downstream of the mutation site; both tumors were heterozygous for the respective mutations. Of the remaining tumors, 7 of the 15 without mutations showed almost no PRKAR1A in the tumor cells, whereas IHC showed that the protein was abundant in nontumorous cells. We concluded that PRKAR1A may be involved by its down-regulation in the pathogenesis of odontogenic myxomas caused by mutations and/or other genetic mechanisms. Of the sporadic, nonfamilial tumors associated with PRKAR1A mutations, the odontogenic type was the first myxomatous lesion found to harbor somatic PRKAR1A sequence changes.

Cyclic AMP-Dependent Protein Kinase RIalpha Subuni↗

PubMed2005

A homozygous cathepsin C mutation associated with Haim-Munk syndrome.

Haim-Munk syndrome (HMS) is a rare autosomal recessive disorder characterized clinically by abnormal palmoplantar hyperkeratosis and destruction of the periodontium, with hallmarks of onychogryphosis and arachnodactyly. Germline mutations in the lysosomal protease cathepsin C gene (CTSC) have been described in a single patient with HMS and in several individuals with the clinically related disorder Papillon-Lefevre syndrome (PLS). We describe a patient with HMS. We have analysed the cathepsin C gene in the proband and her mother. Sequence analysis of CTSC in the proband revealed a homozygous mutation at codon 196 (587T-->C) within exon 4 that altered the conserved leucine to proline (Leu196Pro), whereas the patient's mother was heterozygous for that mutation. The same mutation has previously been described in an unrelated Brazilian family with PLS. An identical single missense mutation in the cathepsin C gene may underlie both PLS and HMS. These findings confirm that HMS and PLS are allelic variants of cathepsin C gene mutations and suggest that other factors (environmental or genetic) may be important determinants of the clinical phenotype of HMS and PLS.

Adult↗

PubMed2005

Herpes simplex virus type 1 shedding in the oral cavity of seropositive patients.

OBJECTIVE: Investigate the frequency of herpes simplex virus type 1 (HSV-1) reactivation in the oral cavity of seropositive patients with previous history of recurrent herpes labialis (recrudescent group) compared with those without any history of recrudescent lesions (asymptomatic HSV-1 infection). In addition, the relation between recrudescence and the presence of the virus in the saliva was assessed. MATERIALS AND METHODS: Fourteen individuals with previous history of herpes labialis (recrudescent group) and 11 HSV-1 seropositive asymptomatic volunteers were included in the study. Swabs were performed periodically in all subjects and the presence of HSV-1 DNA was identified by nested PCR. RESULTS: All the 25 subjects enrolled in the study, revealed at least one positive swab for HSV-1. The frequency of HSV-1 positivity in the group with recrudescent herpes labialis was not statistically different from the other group. Ten subjects of the recrudescent group presented with herpes labialis at least once during the study. CONCLUSIONS: HSV-1 shedding in the oral cavity occurs independently of herpes labialis recrudescence.

Adult↗

PubMed2004

Investigation of the GSalpha gene in the diagnosis of fibrous dysplasia.

Fibrous dysplasia is a benign fibro-osseous disease of bone and its etiology has been previously established. Activating mutations in the gene that encodes the alpha subunit of stimulatory G protein (G(S)alpha) has been described in monostotic and polyostotic fibrous dysplasia and in the McCune-Albright syndrome. The present report describes a patient with monostotic fibrous dysplasia which diagnosis was confirmed by sequencing of the G(S)alpha gene, demonstrating a heterozygous missense mutation on codon 201 (201C --> T). Due to the high prevalence of G(S)alpha gene mutations in fibrous dysplasia in contrast to other benign and malignant fibrous-osseous lesions, mutational analysis are an additional and helpful parameter for the diagnosis of fibrous dysplasia in selected cases.

Adolescent↗

PubMed2004

Ameloblastin gene (AMBN) mutations associated with epithelial odontogenic tumors.

Ameloblastin (AMBN, MIM *601259) gene expresses an important protein (AMBN), present in the organic matrix of enamel. The AMBN protein has an important role in the differentiation of ameloblast cells and epithelium-mesenchyme signaling during odontogenesis which prompted us to investigate this gene in aggressive epithelial odontogenic tumors, such as ameloblastomas, and in some non-aggressive ones, such as the adenomatoid odontogenic tumor and the squamous odontogenic tumor. Six cases of epithelial odontogenic tumors were studied and normal cells of the patient's mucosa were used as negative controls. The results demonstrated novel mutations in all tumors, while mucosal cells showed the wild type DNA sequence. Our data demonstrates that AMBN gene has an important role in the tumorigenesis of subtypes of epithelial odontogenic tumors and that this phenotypic heterogeneity could be caused by genetic heterogeneity.

Ameloblastoma↗

PubMed2004

Effect of bone marrow transplantation on the immunolocalization of p53, hMSH2, and hMLH1 proteins on oral mucosa.

OBJECTIVE: Considering that hMSH2, hMLH1 and p53 are important in maintaining genomic stability of the oral mucosa epithelium, the purpose of the present study was to investigate the immunolocalization of these proteins in the epithelium of the oral mucosa of patients submitted to bone marrow transplantation (BMT) compared with controls. MATERIALS AND METHODS: Twenty-one samples of lip biopsies from BMT recipients were retrieved. Twenty samples of normal lower labial mucosa associated with mucocele in non-transplanted patients were included as control group. The streptavidin-biotin complex stain was used to detect the human DNA mismatch repair proteins hMSH2, hMLH1 and p53 protein. RESULTS: The main findings demonstrated that the mean number of suprabasal epithelial cells positive for MSH2 was statistically higher than the control group. The immunostaining of hMLH1 and p53 at the basal and suprabasal epithelial layers were statistically higher in the oral labial mucosa of the BMT patients compared with controls. CONCLUSION: The present study shows that oral epithelial cells of BMT patients show increased immunolocalization of the DNA repair related proteins.

Adaptor Proteins, Signal Transducing↗

PubMed2003

Oral myiasis by screwworm Cochliomyia hominivorax.

We report a rare case of periodontal myiasis by New World screwworm Cochliomyia hominivorax, an obligatory larval parasite, in a 66-year-old woman. The myiasis occurred in the anterior upper jaw associated with a pre-existent generalised periodontitis. About 40 larvae were removed from the lesion. One week later the periodontal tissues were healing normally and the patient was referred to a periodontist. As all of the larvae were in the last stage, they were probably deposited 5-7 days before.

Aged↗

PubMed2003

Idiopathic bone cavity: a clinical, radiographic, and histological study.

The aim of the present study was to evaluate the clinical, radiographic and histological characteristics of idiopathic bone cavities from the Oral Pathology archives at Universidade Federal de Minas Gerais. Forty-three cases were retrieved. Age, sex, some radiographic variables and morphological variables measured of the connective tissue, were studied. The results showed the men who developed cavities tended to be younger than women (median 16 years (range 11-48) compared with 18 (12-64)). Radiographically rounded lesions that were single, unilocular, and small were more common in younger patients. While rounded cavities occurred mainly in the anterior region, cavities with interdental scalloping occurred in the posterior area. The median age of the patients with thin connective tissue on the wall of the bony cavity was lower than that of those with a thicker lining. In conclusion, the present study shows that there is a significant relation between age and sex, radiographic and histological variables. These findings may contribute to the diagnosis of idiopathic bone cavities.

Adolescent↗

PubMed2003

Lymphangiogenesis in human dental pulp.

AIM: To investigate the impact of inflammation on lymphangiogenesis in human dental pulp. METHODOLOGY: Eleven samples of dental pulp without inflammation and 11 dental pulps with moderate to intense mononuclear cell inflammatory infiltrate associated with dentine caries were selected. The streptavidin-biotin complex stain was used to detect CD31, vascular endothelial growth factor receptor-3 (VEGFR-3) and alpha-smooth muscle actin. The number of lymphatic vessels was obtained by counting the number of vessels positive for CD31 and VEGFR-3 and negative for alpha-smooth muscle actin. RESULTS: The results demonstrated that the mean number (+/-SD) of vessels positive for CD31 and VEGFR-3 (lymphatic vessels) in the group with inflammation (6.09 +/- 1.81) was statistically higher (P = 0.0123) than the mean number in the group without inflammation (3.73 +/- 2.20). CONCLUSION: Increased co-immunostaining of CD31 and VEGF-3 in vessels associated with human dental pulp inflammation occurred, which suggests lymphangiogenesis.

Actins↗

PubMed2002

Release of gamma-[(3)H]aminobutyric acid in rat brain cortical slices by alpha-scorpion toxin.

In this paper, the effect of the alpha-scorpion toxin tityustoxin (TsTX) in the release of gamma-[(3)H]aminobutyric acid ([(3)H]GABA) from rat brain cortical slices is described. The TsTX-stimulatory effect on the release of [(3)H]GABA was dependent on incubation time and TsTX concentration, having an EC(50) of 0.33 microM. Tetrodotoxin (TTX) completely inhibited the TsTX action on [(3)H]GABA release. The scorpion toxin effect was calcium-dependent and involves P/Q calcium channels. beta-Alanine also induces the release of [(3)H]GABA that was not inhibited by TTX but was additive in the presence of TsTX. The data suggest a neuronal origin for the release of [(3)H]GABA by TsTX.

Animals↗

PubMed2002

Translocation of protein kinase C by halothane in cholinergic cells.

Protein kinase C (PKC) is a signal transducing enzyme that is an important regulator of multiple physiologic processes and a potential molecular target for volatile anaesthetic actions. However, the effects of these agents on PKC activity are not yet fully understood. Volatile anaesthetics increase intracellular calcium concentration ([Ca(2+)](i)) in a variety of cells, thus their effects on PKC activity may be indirect due to [Ca(2+)](i) increase. Alternatively, the anaesthetics could directly stimulate PKC activity. In order to distinguish these two possibilities in intact cells, we used a fully functional green fluorescent protein conjugated PKCbetaII (GFP-PKCbetaII) and confocal microscopy to evaluate the dynamic redistribution of PKC in living SN56 cells, a cholinergic cell line, in response to halothane. Halothane induced PKC translocation in SN56 cells transfected with GFP-PKCbetaII. This effect was not suppressed by dantrolene, a drug that blocks halothane-induced Ca(2+) release from intracellular stores in these cells. These findings indicate that halothane induces PKC translocation in SN56 cells independently of its ability to release calcium from internal stores.

Anesthetics, Inhalation↗

PubMed2002

Vascular endothelial growth factor in minor salivary glands: effect of ageing.

Morphological and physiological age changes are described in human salivary glands. Vascular endothelial growth factor (VEGF) is neoangiogenic growth factor found in normal salivary glands. Considering the neoangiogenic properties of VEGF and its important function in inflammation, repair and, probably, in oral mucosa homeostasis, the purpose of the present study was to evaluate the effect of ageing on the immunolocalization of VEGF in minor salivary glands. Paraffin-embedded tissue blocks containing normal labial salivary glands were retrieved and classified according to the patients' age in two groups (< 20 and > 40-year-old). The biotin-streptavidin-peroxidase system was used to detect the VEGF antigen. The results demonstrated that the mean level of VEGF immunoreaction in the young group was not statistically different from the old group when compared by the Mann-Whitney U-test (P = 0.54). This may indicate that although salivary flow reduction may develop in old patients, some properties of the salivary glands may not be affected.

Adolescent↗

PubMed2002

Effects of a bleaching agent containing 35% carbamide peroxide on the immunolocalization of cyclin D and p16.

The evidences that p16 and cyclin D alterations occur in the earlier stages of many human cancers and that its immunolocalization can be used to study the cell cycle regulation, coupled with the possibility that chronic use of carbamide peroxide would induce DNA damage and cell cycle alteration, prompted us to analyse the effect of carbamide peroxide on the immunolocalization of these proteins in rat oral mucosa. Ten male Wistar rats were selected and submitted to topical application of 35% carbamide peroxide over buccal mucosa. The procedures were carried out twice a week for 3 months consecutively. The animals were killed after the last treatment and the buccal mucosa was removed and stored at -70 degrees C. Only distilled water was applied over the buccal mucosa of the control animals. The biotin-streptavidin amplified system was used for identification of cyclin D and p16 antigens and the percentage of basal and suprabasal cells positive for each one were obtained. The results did not show any difference between the experimental and control groups regarding the immunolocalization of cyclin D and p16. In conclusion, the present study showed that chronic use of carbamide peroxide does not induce cell cycle alteration in the oral mucosa of rats.

Animals↗

PubMed2002

An extreme case of cherubism.

We describe an 8-year-old boy who presented with severe facial swelling. This progressed rapidly and 17 months later he died of gastrointestinal and pulmonary infections. The diagnosis was initially brown tumour associated with hyperparathyroidism, but this was revised in the light of laboratory investigations that were within the reference ranges, and normal appearance of the parathyroids on exploration to that of an extreme case of cherubism that behaved in a locally aggressive manner.

Cherubism↗

PubMed2002

Immunolocalization of PTCH protein in odontogenic cysts and tumors.

The human patched gene (PTCH) functions in both embryologic development and tumor suppression. PTCH mutations have been found in odontogenic keratocysts. However, the expression and localization of the protein product of the gene have not been determined in odontogenic tumors and cysts. We investigated 68 odontogenic lesions by immunohistochemistry, and compared their PTCH expression with that in basal cell carcinomas. All odontogenic lesions, including two keratocysts with truncating mutations, were positive for PTCH. Different types of lesions had different amounts of staining. Lack of staining was noted in the majority of basal cell carcinomas. Taken together, these data suggest that odontogenic keratocysts arise with heterozygous mutations of the PTCH gene.

Amino Acid Sequence↗