Biomedical subjects
Publications and source records attributed to M A Lopes.
We report a case of congenital splenic cyst that was identified by prenatal sonography at 25 gestational weeks. Serial scans demonstrated an increase in size during the prenatal period but after birth the cyst progressively decreased in size until its complete regression at 6 months of age.
Salivary duct carcinoma is an uncommon malignant salivary gland tumor that occurs predominantly in the parotid gland. Oral involvement is extremely rare, with few cases having been reported in the literature. The tumor is characterized by an aggressive behavior and has a poor prognosis. We describe a case of salivary duct carcinoma arising in the hard palate of a 63-year-old man. Immunohistochemical analysis revealed that tumor cells tested positive for cytokeratin, epithelial membrane antigen, proliferating cell nuclear antigen, Ki67, p53, laminin, and collagen IV. Despite radical surgical resection, bilateral neck dissection, and postoperative radiotherapy, liver metastases developed, and the patient subsequently died of his disease.
Although liposarcoma is one of the most common soft tissue sarcomas, its location in the oral cavity is very rare. To our knowledge, only 43 cases of liposarcoma originating in the oral tissues have been reported in the English-language literature. In this article, we report a case of well-differentiated liposarcoma affecting the cheek of a 28-year-old man and review the oral liposarcoma literature. Immunohistochemical analysis of the tumor revealed an MDM2+/CDK4+/p53+ immunophenotype that is consistent with the immunohistochemical profile of well-differentiated liposarcoma originating in other areas of the body. Quantitative polymerase chain reaction analysis of the DNA levels of the MDM2 (human homologue of the murine double-minute type 2), CDK4 (cyclin-dependent kinase 4), and SAS (sarcoma amplified sequence), genes was performed, revealing only SAS gene amplification. The possibility of misdiagnosis of oral liposarcoma because of its sometimes inconspicuous clinical and microscopic features is emphasized. Careful pathologic examination of liposarcoma is essential for discrimination from benign adipose tissue neoplasms and for precise histologic classification, both of major prognostic significance. Possible implications of molecular and cytogenetic analysis for unraveling the pathogenesis and determining the prognosis of liposarcoma are discussed.
INTRODUCTION AND OBJECTIVES: Hospital discharge on day 10 after acute myocardial infarction (AMI) is still frequent in our hospital. The present study aims at evaluating the occurrence of cardiac events on day 5, 7 and 10, in patients with AMI who had an uncomplicated course for 72 hours after thrombolysis, as well as a cost-effectiveness analysis on an earlier discharge. METHODS: We retrospectively studied consecutive patients admitted with AMI for a period of 5 years, submitted to thrombolysis who suffered no events (recurrent ischemia, reinfarction, coronary revascularization, heart failure, arrhythmias implicating electric cardioversion or dysfibrilation, pacemaker or death) within the first 72 hours (n = 128; 101 males and 27 females, mean age 64.1 +/- 12.8). Patients were divided into two groups, with no events occurring by discharge (group I, n = 119) or with events between 72 hours and discharge (group II, n = 9). The latter were subdivided according to whether events occurred between 72 hours and day 5, between days 6 and 7 or between 8 and 10. RESULTS: Group I and II were not significantly different regarding vascular risk factors, prior coronary disease and infarction location. Group I was mainly constituted of males, younger than those in group II and with preserved systolic LV function. Between 72 hours and discharge, there were no events in 93% of the patients (119) and events occurred in 7% (9 patients). Two cases of cardiac events occurred until day 5 (1.6%) one angina and one death, two patients with complications between days 6 and 7 (1.6%), both heart failure, and 5 patients suffered events after day 7 (4%), 3 angina and 2 deaths. Dead patients (3 cases--2.3%) were older, had prior AMI, mostly with unpreserved systolic LV function and prior ischemic heart disease. All of them had sudden death. The most frequent non-fatal complications were recurrent ischemia and heart failure. CONCLUSIONS AND IMPLICATIONS: In patients with AMI who had an uncomplicated course for 72 hours after thrombolysis, the risk of cardiac events by the 10th day is low. It occurs randomly in time. In this group of patients it seems of no effectiveness to lengthen hospitalization. An earlier discharge may be advantageous since it does not significantly increase the risk that a longer hospitalization could prevent.
Zeins, the maize storage proteins, are the most abundant proteins in the corn endosperm, and are synthesized on the rough endoplasmatic reticulum and deposited in discrete organelles called protein bodies. Several authors, using circular dichroism and optical rotatory dispersion, have concluded that these proteins have a high alpha-helical content in alcoholic solution. In this work we have studied these proteins, within the protein bodies themselves and after extraction from the corn grains with 70% ethanol, using NMR (nuclear magnetic resonance) spectroscopy. We conclusively demonstrate the presence of free fatty acids within both the protein bodies and also in the alcohol extracted alpha zeins. We present evidence for a direct interaction between the free fatty acids and the alpha zein proteins within the protein body and suggest possible mechanisms by which such an association has arisen during the evolution of the maize endosperm.
P2O5 glass reinforced hydroxyapatite composite materials were prepared through a liquid-phase sintering process. Secondary phases, beta- and alpha-tricalcium phosphates (beta-TCP and alpha-TCP), were formed in the microstructure of the composites, due to the reaction between the liquid glassy phase and the hydroxyapatite matrix. The dynamic Young's modulus (E) and shear modulus (G) of these composites were determined using an impulse excitation method. By applying the Duckworth-Knudsen equation, the elastic property results were correlated with the relative proportion of beta-TCP and alpha-TCP phases and with the porosity percentage present in the microstructure. Glass reinforced hydroxyapatite composites showed lower Young's and shear moduli than unmodified hydroxyapatite, mainly due to the presence of beta-TCP phase. The Duckworth-Knudsen model demonstrated an exponential dependence of E and G modulus with porosity and mathematical equations were derived for composite materials with porosity correction factors (b) of 4.04 and 4.11, respectively, indicating that porosity largely decreased both E and G moduli.
This investigation examined primarily epidermal specializations of the adult horse tongue by light, scanning and transmission electron microscopy. Samples were collected from seven regions of the normal tongue of various breeds of horse. The filiform papillae, present on the dorsal and lateral aspects but not the ventral aspect of the tongue, were short, slender and finger-like structures with variable-shaped terminae. The epidermal thickness and height of dermal ridges were reduced on fungiform and vallate papillae, but tissue architecture and keratinocyte ultrastructure of most of the lingual epidermis corresponded to the common mammalian epidermal paradigm. One unique finding was the highly localized clustering of epidermal cells with exceptionally high content of PAS-negative trichohyalin cytoplasmic granules at a location atop the dermal ridges and beneath the base of filiform papillae. These granular cells were immediately subjacent to clusters of clear, non-granulated epidermal cells. It is believed that this integumentary specialization may enhance the structural strength at this localized site of the tissue architecture, in relationship to the mechanical papillae.
The hindgut is the major site in the horse for nutrient digestion and absorption. Most of this activity occurs in the large intestinal compartments, i.e., cecum, right and left ventral colon and left and right dorsal colon. The colonic pelvic flexure is a short and narrow loop connecting the left ventral and left dorsal colon. It is not significant directly in digestive and absorptive processes but plays an important functional role in regulating colonic aboral and retropropulsive transit of digesta through its motility pacemaker activity. The pelvic flexure also contributes to the pathophysiology of colic, the leading cause of death in horses. Its narrow lumen may contribute to colonic impaction, and malfunctions of the pacemaker may contribute to volvuli and colonic displacements. Neuronal and ganglion density of the myenteric plexus is increased at the pelvic flexure and adjacent left dorsal colon pacemaker region. Contractile activity, vasoactive intestinal peptide (VIP) and neurokinins-1 and -3 are all enhanced in the pelvic flexure. The mucosa histologically resembles that of the ventral and dorsal colon, with apically-granulated principal cells and goblet cells lining the luminal surface. Clustered intranuclear inclusions resembling the cytoplasmic granules are also observed by electron microscopy in the principal cells as elsewhere in the horse colon. Further neuroendocrine and morphologic investigation of the pelvic flexure is warranted due to the great importance of this localized region for normal function and pathophysiology.
Three cases of generalized and severe HGF in young patients of the same family without other features are reported. The purpose of this article is to present documented cases and discuss the identification, treatment, and control of the disease. The histopathological characteristics of HGF are emphasized.
Wettability and zeta potential studies were performed to characterize the hydrophobicity, surface tension, and surface charge of P2O5-glass-reinforced hydroxyapatite composites. Quantitative phase analysis was performed by the Rietveld method using GSAS software applied to X-ray diffractograms. Surface charge was assessed by zeta potential measurements. Protein adsorption studies were performed using vitronectin. Contact angles and surface tensions variation with time were determined by the sessile and pendent drop techniques, respectively, using ADSA-P software. The highest (-18.1 mV) and lowest (-28.7 mV) values of zeta potential were found for hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP), respectively, with composite materials presenting values in between. All studied bioceramic materials showed similar solid surface tension. For HA and beta-TCP, solid surface tensions of 46.7 and 45.3 mJ/m2, respectively, were obtained, while composites presented intermediate surface tension values. The dispersive component of surface tension was the predominant one for all materials studied. Adhesion work values between the vitronectin solution and HA and beta-TCP were found to be 79.8 and 88.0 mJ/m2, respectively, while the 4.0 wt % glass composites showed slightly lower values than the 2.5 wt % ones. The presence of beta-TCP influenced surface charge, hydrophobicity, and protein adsorption of the glass-reinforced HA composites, and therefore indirectly affected cell-biomaterial interactions.
CaO-P(2)O(5) glasses with additions of MgO and CaF(2) were used as a sintering aid of hydroxyapatite, and glass-reinforced hydroxyapatite composites obtained. Glasses promoted significant changes in the microstructure of the composites, namely with the formation of tricalcium phosphate secondary phases, beta and alpha-TCP. Quantitative phase analysis was performed by the Rietveld method using General Structure Analysis Software. Grain size measurements were carried out on SEM photomicrographs, using a planimetric procedure according to ASTM E 112-88. Flexural bending strength was determined from concentric ring-on-ring testing. Flexural bending strength (FBS) of glass-reinforced hydroxyapatite composites was found to be about twice or three times higher than that of unreinforced hydroxyapatite and tended to depend more on porosity and beta and alpha-TCP secondary phases, rather than on grain size. Traces of alpha-tricalcium phosphate significantly enhanced the strength of the composites. Using the rule of mixtures to estimate the zero porosity bending strength, the Duckworth-Knudsen model applied to the composites gave a porosity correction factor, b, with a value of 4.02. Weibull statistics were also used to analyze biaxial strength data and the level of reinforcement obtained by comparing failure probability for the composites and for the unreinforced hydroxyapatite. Lower activation energies for grain growth were observed for the composites compared to unreinforced hydroxyapatite, which should be attributed to the presence of a liquid glassy phase that promotes atomic diffusion during the sintering process.
Fracture toughness and hardness properties of CaO-P2O5 glass-reinforced hydroxyapatite composites have been assessed using indentation techniques and results calculated according to Laugier and Evans' equations. Both properties showed to be dependent upon several microstructural characteristics, namely residual porosity and the percentage of secondary beta and alpha tricalcium phosphate phases in the structure of the composites. Composites presented a Palmqvist-type indentation crack system, which is the specific crack system addressed by Laugier's approach. Fracture toughness determinations according to Evan's equation, which is a universal one and adapted to both median and Palmqvist crack systems, did not correlate well with Laugier determinations.
We present a retrospective study of 196 patients with intraoral minor salivary gland tumours, 128 malignant and 68 benign, diagnosed from 1954 to 1993 in the A. C. Camargo Hospital, São Paulo, Brazil. Sixty-five percent of the cases occurred in the palate, followed by tongue (9.7%) and retromolar area (6.1%). Pleomorphic adenoma was the most common benign tumour, and mucoepidermoid carcinoma was predominant among the malignant tumours. Surgery was the main treatment method and postoperative radiotherapy and radiotherapy alone were used in 40 and 15 patients, respectively. Local recurrence was observed in two patients with pleomorphic adenoma and in eight patients with malignant tumours. Regional lymph node metastases occurred in four cases and distant metastases in five. Forty-six of 47 patients with benign tumours who were followed up from 1 to 7 years were alive without disease. Twenty-four of 79 patients with malignant tumours who were followed up for at least 5 years died due the tumour and 47 were alive without disease.
A case of congenital lower lip pits is presented. The main characteristics of these malformations, the importance of the diagnosis and the surgical treatment are discussed.
Flow cytometry (FCM) was examined as a possible procedure for measuring in vitro the biocompatibility of implant materials for orthopedic and dental surgery. The human osteoblast-like cell line MG63 was grown on hydroxyapatite (HA) and P2O5 glass-reinforced HA composite discs and compared with the same cells grown on polystyrene culture dishes. While morphological observation at the light and electron microscopic levels showed no major deleterious effects, FCM indicated that cell size was somewhat reduced, particularly by growth on the HA composite. Morever, this material also appeared to delay the progression of the cells from the G0/G1 into the S phase of the cell cycle. In addition to this low level of inhibition of cell growth relative to control cultures, FCM analysis also demonstrated that the glass-reinforced HA caused some down-regulation of the expression of osteocalcin and fibronectin, two antigens which play a vital part in the integrity and function of bone and soft connective tissue, respectively. These results thus show, first, that although HA and the HA composite used in these experiments were generally biocompatible, they nevertheless had certain suboptimal effects on the cells; and second, that FCM could be a highly useful procedure for effectively screening and evaluating important biological responses to implant materials.
BACKGROUND: Minor salivary gland carcinomas are uncommon tumors of the oral cavity. The decision regarding treatment remains controversial. The main objective of this paper is to report on the survival results of 128 patients treated in a single institution. METHODS: Tumor sites were: hard palate (62 cases), tongue (16 cases), buccal mucosa (13 cases), soft palate (12 cases), and other sites (25 cases). The most common histology was mucoepidermoid carcinoma (76 cases). Clinically metastatic lymph nodes were palpable in 21 patients. Cox regression technique was used to construct the mathematical-statistical models, aiming to predict the risks of recurrence and of death as functions of the different variables under study. RESULTS: The 5-year overall survival rates were, respectively, 85.9% and 87.7% in the groups of patients treated by surgery or combined therapy. There were significant differences in survival rates according to N stage, bone involvement, tumor histology, sex, and type of surgery. CONCLUSIONS: Most of the recurrences were at the site of primary tumor; neck metastases were rare at presentation and after initial treatment. Prognosis involves several factors related to stage, histology, and treatment.
Glass-reinforced HA composites were produced using phosphate-based glasses, and a structure refinement was carried out to determine the effect of the glass on the structure of the residual HA. Quantitative phase analysis showed that the glass causes some of the HA to decompose to beta-TCP and, at higher temperatures, to alpha-TCP. It also was indicated that when three phases were present, the formation of the alpha-TCP arose from decomposition of the beta-TCP and not from further decomposition of HA to alpha-TCP. The unit cell dimensions showed a decrease in the a axis and an increase in the c axis, giving an overall unit cell decrease in volume. There also was a significant effect based on the amount of glass added. The changes found in the composite containing the 4 wt% glass were attributed to the loss of carbonate and loss of hydroxyl. This was expected to cause shrinkage in the unit cell; however this was not seen, and therefore the major changes in the unit cell were attributed to the ions from the glass taking an interstitial role in the HA structure, thus not allowing the unit cell to shrink as much as expected.
Many diseases can cause orofacial pain, and the diagnosis must be established before final treatment. This case report presents a patient with orofacial pain that was diagnosed as an acute pulpitis. However, there was no evidence of this problem on examination. After 4 days, the patient showed multiples vesicles on the face, and a herpes zoster viral infection was diagnosed. The patient was treated with acyclovir and, after 2 yr, she still complains of facial sensitivity.