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Biomedical subjects

M A Castro

Publications and source records attributed to M A Castro.

65 records · Page 4Linked to original sources
PubMedDate not supplied

Synthesis and antineoplastic activity of cyclolignan aldehydes.

Several aldehydes related to methyl 9-deoxy-9-oxo-alpha-apopicropodophyllate, a selective antitumour agent against the HT-29 colon carcinoma, have been prepared and evaluated for their cytotoxic activities on four neoplastic cell lines (P-388, A-549, HT-29 and MEL-28). All of them lacked the lactone ring but maintained their cytotoxicity at, or under, the microM level.

Aldehydes↗
PubMedDate not supplied

[Neoplasms associated with esophageal epidermoid carcinoma].

INTRODUCTION: The esophageal epidermoid cancer has an important association with aerodigestive tract neoplasms and possibly share the same risk factors. Furthermore, other neoplasms can be associated with esophagus cancer. OBJECTIVE: To analyze retrospectively the patients with esophageal epidermoid cancer (EEC) and associated neoplasms, treated by the Esophagus Stomach and Small Intestine Group of Surgery at Hospital de Clinicas de Porto Alegre from January 1988 to June 1995. PATIENTS AND METHODS: Nineteen (7.28%) of the 261 studied patients had associated neoplasms to the EEC. Ten patients presented synchronic tumours and 9 metachronic ones. The predominant sex was the masculine with 17 cases. The mean age was 62.52 years in the moment of the esophageal cancer diagnostic. RESULTS: The aerodigestive tumours, squamous carcinomas in totality, represented the predominant associated neoplasm histological type in 68.42% of the cases. The most frequent associated aerodigestive tumours site was the respiratory tract (53.8%), followed by the oral cavity and oropharynx (23%) and larynx (23%). In our sample, twelve patients were smokers and 9 were alcohol abusers. In relation to the EEC treatment, surgery was performed in 6 patients. The associated neoplasm was treated with radical surgery in 11 patients and radiotherapy in 5. Surprisingly 4 cases (21%) of gastric adenocarcinoma associated to the EEC were diagnosed, treated with radical surgery in 3 patients. CONCLUSION: The authors call attention to the importance of a criterial staging as well as the follow up in patients with EEC owing to the significant association with others neoplasms, principally with aerodigestive tumours, and discuss the common risk factors possibility: tobacco and alcohol use. Important association with gastric neoplasms were found in this casuistry.

Adult↗
PubMedDate not supplied

[Methods to assess the ex vivo growth capacity of mesothelial cells obtained directly from peritoneal effluent].

The anatomical and functional integrity of mesothelial cells (MC) is necessary for peritoneal membrane stability. At present, there is no satisfactory method to assess MC function and regenerative capacity in individual peritoneal dialysis (PD) patients. MC may be cultured from peritoneal biopsy specimens, but peritoneal biopsy is an invasive procedure that cannot be performed serially. The aim of this study is to explore the feasibility of serial culture of MC from the peritoneal effluent of PD patients. Fifty-two randomly selected PD patients were studied. MC were obtained from the peritoneal effluent of nocturnal 2.27% glucose exchanges and cultured in T25 tissue culture flasks. Subconfluent MC cultures were obtained in 80.7% of patients. At this stage, the percentage of cells in the tissue cultured flask characterized as MC by morphology and immunostaining had increased to 95.5%. MC were then subcultured in multi-well culture plates, where they showed exponential cell growth until day 16. Nine (17%) patients released low numbers of MC into the effluent and MC could not be cultured to subconfluence. One additional patient released and apparently adequate number of MC that repeatedly failed to reach confluence. Patients showed the same behavior in several cultures performed. In conclusion, peritoneal MC released into peritoneal effluent are accessible for profound analysis by a culture technique. This technique opens the possibility of serial follow-up of the biology of MC individual PD patients.

Cell Division↗
PubMedDate not supplied

Icodextrin effluent leads to a greater proliferation than glucose effluent of human mesothelial cells studied ex vivo.

OBJECTIVE: To compare the effect of glucose (Glu) and icodextrin (Ico) dialysate on in vitro culture of mesothelial cells (MC) from peritoneal dialysis (PD) patients. DESIGN: Prospective, controlled comparative study on the effects of two PD solutions. SETTING: A tertiary-care public university hospital. PATIENTS: Sixteen PD patients regularly using Glu dialysate were asked to collect an 8-hour dwell peritoneal effluent on 2 different days, with an interval shorter than 7 days. In the first collection, 2.27% Glu solution and in the last, 7.5% Ico solution was infused. Human MC were isolated from the nocturnal peritoneal effluent bags and grown ex vivo. MAIN OUTCOME MEASURES: Mesothelial cell proliferative capacity ex vivo. RESULTS: Mesothelial cells were present in all patient dialysates except that of a single patient's Glu dialysate. The number of MC drained was similar with both solutions. After the initial culture reached confluence, MC were identified in 14 and 12 patients receiving Ico and Glu, respectively. However, in 1 patient using Ico and in 2 using Glu, the MC count at this stage was so low that further subculture could not be performed. Cells from Ico-derived solutions exhibited a higher degree of proliferation than cells from Glu-derived solutions. The morphology of MC was also different. Cells from drained effluent were typical in 11 patients using Glu solution in contrast with 14 patients using Ico. At confluence, the percentages of typical appearance were 50% and 92.9% (p < 0.05) in Glu and Ico respectively. CONCLUSIONS: Mesothelial cells taken from icodextrin effluent show a greater proliferation ex vivo than those taken from glucose effluent.

Cell Division↗
PubMedDate not supplied

Vascular endothelial growth factor (VEGF) levels in peritoneal dialysis effluent.

BACKGROUND: Long-term peritoneal dialysis (PD) patients who develop peritoneal ultrafiltration failure have an abnormally large number of capillaries and sclerotic changes in peritoneal biopsy. Peritoneal vascular endothelial growth factor (VEGF) production has been suggested to explain the higher levels in peritoneal effluent than in plasma. The high effluent VEGF levels have been related to peritoneal changes consisting of increased permeability to small molecules. To further analyze the relationship between peritoneal neoangiogenesis induced by VEGF and peritoneal transport, we studied peritoneal effluent VEGF levels in active PD patients. METHODS: VEGF levels were determined in serum and plasma, and in peritoneal effluent (PE) after 4, 8 and 15 h dwell times. RESULTS: PE VEGF levels were 58.6+/-33.7 pg/mL, with a mean VEGF D/P ratio of 0.45+/-0.29 (range 0.06-0.93). In low-transport patients (n = 7) this ratio did not differ from high-average ones (n=5) (0.48+/-0.3 and 0.41+/-0.1, NS). In multivariate analysis, the VEGF D/P ratio showed no correlation with the independent variables included in this study. VEGF levels were higher in 15 h than in 8 h effluent; so the VEGF D/P ratios were higher as well. Regression analysis showed a direct correlation between PEVEGF levels and dwell time (r: 0.57, p = 0.03), but not between VEGF D/P ratio and dwell time. PEVEGF levels directly correlated with effluent protein content. Regression analysis showed no correlation between PEVEGF levels and age, time on PD, days of peritonitis, urea and creatinine-mass transfer coefficients, ultrafiltration capacity, and accumulated glucose dose. Multivariate regression analysis showed correlation only between PEVEGF levels and dwell time, but not with the other independent variables. CONCLUSIONS: This study confirms that VEGF is present in fresh PE from PD patients at levels that suggest local production and filtration from plasma. Peritoneal effluent VEGF levels are not significantly associated with peritoneal functional parameters and background, and seem to be influenced by ultrafiltration in a dilution process. We believe that the role of VEGF in peritoneal pathophysiology is part of a complex relationship involving multiple peritoneal structures and other growth factors, including local counteracting factors for VEGF that regulate neoangiogenesis.

Dialysis Solutions↗
PubMedDate not supplied

[Acute arterial thrombosis of the extremity in pseudoxanthoma elasticum].

We report a case of a patient with an elastic pseudoxanthoma (PXE) who presented an acute ischaemia at the left lower limb. The cause of such ischaemia was a thrombosis into the iliac and femoropopliteal arteries. Patient underwent a surgical procedure. The arteriopathy associated with a PXE rarely cause an arterial major occlusion. We did not found a case of acute arterial thrombotic ischaemia and PXE, treated with direct arterial revascularization in the reviewed literature.

Acute Disease↗
PubMedDate not supplied

Patient-specific computational fluid dynamics modeling of anterior communicating artery aneurysms: a study of the sensitivity of intra-aneurysmal flow patterns to flow conditions in the carotid arteries.

BACKGROUND AND PURPOSE: The purpose of this study was to investigate the effects of unequal physiologic flow conditions in the internal carotid arteries (ICAs) on the hemodynamics of anterior communicating artery aneurysms. METHODS: Patient-specific computational fluid dynamics models of 2 cerebral aneurysms were constructed from bilateral 3D rotational angiograms. The flow dynamics of the aneurysm sac were analyzed under the effect of unequal mean flows, phase shifts, and waveforms between the ICAs. A total of 9 simulations were performed for each patient; cine flow velocity simulations and unsteady wall shear stress (WSS) maps were created for each flow condition. Time-dependent curves of average WSS magnitude over selected regions on the aneurysms were constructed. RESULTS: Mean flow unbalances in the feeding vessels tended to shift the regions of elevated WSS towards the dominating inflow jet and to change the magnitude of the WSS peaks. The overall qualitative appearance of the WSS distribution and velocity simulations was not substantially affected. Phase and waveform asymmetry increased the temporal complexity of the hemodynamic patterns and tended to destabilize the flow pattern. CONCLUSIONS: Differences in the relative phase and waveform shape in ICAs can significantly affect the complexity and stability of the hemodynamic force distributions. The magnitude of these effects is related to the geometry of the aneurysm and the feeding vessels. Conditions affecting the flow characteristics in the parent arteries of cerebral aneurysms with more than 1 avenue of inflow should be incorporated into flow models.

Angiography↗
PubMedDate not supplied

[Emphysematous cystitis].

Emphysematous cystitis constitutes an uncommon clinical radiological entity. (Approximately 160 cases in the literature). We offer five cases of emphysematous cystitis, all of which occurred in women aged 60-80 (X = 74.2). All of them except one proved to be known diabetics and the glycemia figures at the time of being attended were above the limits of normality. In no case was pneumaturia observed, and the main symptoms displayed were those of the cystitis type together with pain in the hypogastrium and macroscopic hematuria. Simple abdomen radiology was the diagnosis procedure in all cases. The treatment applied permitted the favourable evolution and resolution of the process.

Aged↗