Biomedical subjects
J Almeida
Publications and source records attributed to J Almeida.
Progression of mitral regurgitation. A prospective Doppler echocardiographic study.
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[Ascending aorta dissection as a cause of myocardial infarction].
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Correlation between cytogenetic abnormalities and disease characteristics in multiple myeloma: monosomy of chromosome 13 and structural abnormalities of 11q are associated with a high percentage of S-phase plasma cells.
BACKGROUND AND OBJECTIVES: Cytogenetic studies in multiple myleoma (MM) are limited by the difficulties in obtaining metaphases that can be investigated and few studies have analyzed the relationship between cytogenetics and clinical disease characteristics. The aim of our study was to analyze the recurrent cytogenetic changes in MM and to correlate them with clinical and biological characteristics including the percentage of S-phase plasma cells (PCs). DESIGN AND METHODS: Chromosomal abnormalities were analyzed in 86 patients with MM. In all patients, two types of cultures (5 d culture with interleukin-4 and unstimulated 72 h culture) were used for cytogenetic analysis. DNA content analysis (ploidy and cell cycle analysis) together with the most relevant clinical and biological disease features were studied. RESULTS: Cytogenetic analysis was successful in 72 of the 86 patients (84%). Forty-seven patients (65%) had an abnormal karyotype. The most frequent trisomies involved chromosomes 3, 5, 9, 11, 15, 19, 22, 1, 7, 17, 18, and 21, and monosomies affected chromosomes 13 and 8, while structural changes involved chromosomes 1, 11, 14q32, 4p16 and 16q22-23. Patients with abnormal karyotype displayed a poor performance status, advanced stage, anemia and a high percentage of bone marrow plasma cells. In addition, MM patients with -13/13q- and 11q abnormalities showed a significantly higher proportion of S-phase PCs (p=0.02). INTERPRETATION AND CONCLUSIONS: In summary, our study shows a relationship between unfavorable cytogenetics (-13/13q-/11q abnormalities) and a high percentage of S-phase PCs, a well-known adverse prognostic factor.
In vivo nuclear magnetic resonance studies of glycolytic kinetics in Lactococcus lactis.
The metabolism of glucose by nongrowing cells of L. lactis strain MG5267 was studied under controlled conditions of pH, temperature, and gas atmosphere (anaerobic and aerobic) using a circulating system coupled to nuclear magnetic resonance (NMR) detection that allowed a noninvasive determination of intracellular pools of intermediate metabolites by 13C-NMR with a time resolution of 30 seconds. In addition, intracellular parameters, such as pH, NTP levels, and concentration of inorganic phosphate in the cytoplasm, could be monitored on-line by 31P-NMR with a time resolution of approx. 3 min. The time course for the concentrations of intracellular fructose 1,6-bisphosphate (FBP), 3-phosphoglycerate (3-PGA), and phosphoenolpyruvate (PEP), together with kinetic measurements of substrate consumption and endproducts formation, were used as a basis for the construction of a mechanistic model for glycolysis. In vivo measurements were complemented with determinations of phosphorylated metabolites in perchloric acid extracts. A top-down model was developed by simplifying the metabolism to the resolution allowed by the experimental data collected by in vivo NMR (grouped in seven metabolic steps). This simplified mechanistic model was adjusted to the metabolite concentrations determined by in vivo NMR. The results obtained led to the rationalization of the dynamics of glucose metabolism as being driven largely by ATP surplus. This excess causes accumulation of FBP due to NAD+ limitation, whose regeneration is dependent on downstream pyruvate reduction. The model was capable of predicting qualitative shifts in the metabolism of glucose when changing from anaerobic to aerobic conditions.
Correlation of rhodamine 123 efflux by neoplastic plasma cells with clinical and biological characteristics of multiple myeloma.
Although a variable proportion of multiple myeloma patients can achieve response with conventional chemotherapy, residual tumor cells, which are refractory, finally reemerge leading to disease progression. The expression of the multidrug resistance protein (MDR1) has been one of the most extensively explored mechanisms of drug resistance and has been related to a poor response to chemotherapy in several human tumors. Nevertheless, a careful analysis of the literature on MDR1 expression in multiple myeloma (MM) shows the existence of disturbing discrepancies as regards both the incidence of MDR1 over-expression and its clinical value. A prerequisite for the assessment of MDR1 in tumor cells should be the identification of the neoplastic cells present in the sample. This is particularly important in MM, where the percentage of tumor cells in bone marrow (BM) is relatively low. In the present study we have analyzed the functional expression of MDR1 in BM plasma cells (PC), from a group of 40 untreated MM patients. For that purpose, the rhodamine 123 efflux assay was used in combination with specific staining for plasma cells (CD38 strong+). The mean fluorescence channel (MFC) of rhodamine 123 in myelomatous PC from MM patients was 311 and 110 after incubating cells with this fluorochrome for 15 and 60 min, respectively. The median percentage of rhodamine 123 elimination by BM PC was of 61% (range: 0.29 to 88%). Upon analyzing the relationship between the ability of myelomatous PC to eliminate rhodamine 123 and other clinical and biological disease characteristics we found that, within the group of patients displaying high MDR1 expression (>61% rhodamine efflux), there was a higher incidence of cases with bone disease (P = 0.014) and advanced clinical stages (P = 0.031), greater calcium (P = 0.007) and creatinine serum levels (P = 0.061), and lower levels of albumin in serum (P = 0.015). All these parameters are usually associated with a poor prognosis. When we analyzed the possible relationship between the ability of BM PC to eliminate rhodamine 123 and the presence of numerical chromosome abnormalities we observed that a low MDR1 expression was related to a higher incidence of trisomies of chromosomes 6 and 17, although these differences did not reach statistical significance (P = 0.06). In spite of these associations, from the prognostic point of view, MDR1 expression did not correlate with other relevant prognostic factors, response to treatment (P = 0.38) or overall survival (P = 0.12).
Atrioventricular septal defect following blunt chest trauma.
The authors describe an acquired atrioventricular septal defect that has resulted from a blunt chest trauma. Besides being an uncommon traumatic heart injury, this case has the particularities of the non-involvement of other adjacent anatomical structures and the long delay between the accident and the occurrence of the myocardial rupture.
High-sensitive immunophenotyping and DNA ploidy studies for the investigation of minimal residual disease in multiple myeloma.
Sensitive techniques for monitoring minimal residual disease (MRD) in multiple myeloma (MM) are needed to evaluate the effectiveness of new intensive treatment strategies. The aim of the present study was to explore the applicability and sensitivity of flow cytometry immunophenotyping and DNA ploidy studies for the investigation of residual myelomatous plasma cells (PC) in MM patients. Bone marrow (BM) samples from 61 untreated MM patients were immunophenotypically analysed with a panel of 21 monoclonal antibodies, using a high-sensitive method based on a two-step acquisition procedure through a SSC/CD38 -CD138+ 'live-gate'. Overall, in 87% of MM cases, PC displayed an aberrant phenotype at diagnosis. The most important aberrant criteria were: antigen over-expression of CD56 (62%), CD28 (16%) and CD33 (6%) and asynchronous expression of CD117 (28%), sIg (21%) and CD20 (10%). DNA aneuploidy was found in 62% of cases. The simultaneous use of these two techniques allowed the detection of aberrant/aneuploid PC in 95% of the cases. Based on dilutional experiments, the detection limit of both techniques ranged from 10(-4) to 10(-5). In 29 stem cells harvests and 19 BM samples obtained 3 months after autologous transplantation, we have investigated the presence of residual myelomatous PC; they were detected in 44% of the stem cell collections and in 61% of the BM samples obtained after transplant. The percentage of pathological PC did not significantly change during the days of harvest. In summary, the present study shows that the combined use of immunophenotyping and DNA ploidy studies is a suitable approach for MRD investigation in MM patients based on their applicability (95% of cases) and sensitivity (up to 10(-5)).
Extensive characterization of the immunophenotype and pattern of cytokine production by distinct subpopulations of normal human peripheral blood MHC II+/lineage- cells.
Dendritic cells (DC) represent the most powerful professional antigen-presenting cells (APC) in the immune system. The aim of the present study was to analyse, on a single-cell basis by multiparametric flow cytometry with simultaneous four-colour staining and a two-step acquisition procedure, the immunophenotypic profile and cytokine production of DC from 67 normal whole peripheral blood (PB) samples. Two clearly different subsets of HLA-II+/lineage- were identified on the basis of their distinct phenotypic characteristics: one DC subset was CD33strong+ and CD123dim+ (0.16 +/- 0.06% of the PB nucleated cells and 55.9 +/- 11. 9% of all PB DC) and the other, CD33dim+ and CD123strong+ (0.12 +/- 0.04% of PB nucleated cells and 44.53 +/- 11.5% of all PB DC). Moreover, the former DC subpopulation clearly showed higher expression of the CD13 myeloid-associated antigen, the CD29 and CD58 adhesion molecules, the CD2, CD5 and CD86 costimulatory molecules, the CD32 IgG receptor and the CD11c complement receptor. In addition, these cells showed stronger HLA-DR and HLA-DQ expression and a higher reactivity for the IL-6 receptor alpha-chain (CD126) and for CD38. In contrast, the CD123strong+/CD33dim+ DC showed a stronger reactivity for the CD4 and CD45RA molecules, whereas they did not express the CD58, CD5, CD11c and CD13 antigens. Regarding cytokine production, our results show that while the CD33strong+/CD123dim+ DC are able to produce significant amounts of inflammatory cytokines, such as IL-1beta (97 +/- 5% of positive cells), IL-6 (96 +/- 1.1% of positive cells), IL-12 (81.5 +/- 15.5% of positive cells) and tumour necrosis factor-alpha (TNF-alpha) (84 +/- 22.1% of positive cells) as well as chemokines such as IL-8 (99 +/- 1% of positive cells), the functional ability of the CD123strong+/CD33dim+ DC subset to produce cytokines under the same conditions was almost null. Our results therefore clearly show the presence of two distinct subsets of DC in normal human PB, which differ not only in their immunophenotype but also in their functionality, as regards cytokine production.
Immunophenotype of bone marrow mast cells in indolent systemic mast cell disease in adults.
One of the major advances in the histological diagnosis of bone marrow (BM) involvement in mastocytosis has been the specific immunohistochemical detection of tryptase on most cells (MC), which has shown to be of great diagnostic value, especially in cases of malignant mastocytosis. On the other hand, recent studies have clearly shown that bone marrow mast cells can be specifically identified and accurately enumerated using multiparametric flow cytometry, which allow a systematic analysis of the immunophenotypic characteristics of bone marrow mast cells. Once this flow cytometric approach was applied for the analysis of BMMC from mastocytosis patients clear immunophenotypical differences were found between BMMC from normal individuals and adults with mastocytosis. The most characteristic immunophenotypic feature, both in malignant and adult indolent systemic mast cell disease, being the coexpression of CD2 and CD25 antigens, never present in normal bone marrow mast cells and, which constitute an aberrant hallmark of bone marrow mast cells in adult mastocytosis. Furthermore, bone mast cells from mastocytosis display a higher reactivity for CD35, CD63, and CD69 activation-associated antigens. Based on these results it could be concluded that the use of multiparametric flow cytometric immunophenotyping of BMMC in adult patients suffering from cutaneous mastocytosis can be of great utility for the diagnosis of BM involvement; additionally, this might also help to establish the real incidence of BM involvement in cutaneous mastocytosis.
In vitro growth in acute myeloblastic leukemia: clinico-biological correlations.
In the present review we analyse the current knowledge about the growth properties of AML progenitor cells and their relationship with other clinico-biological characteristics of the disease. Leukaemic colony forming unit L-CFU is considered to be the clonogenic cell in AML and more immature than the blast cell population. Our studies have shown that in leukaemic hematopoiesis colony forming cells can exist among both cell fractions CD34+ and CD34-. Optimal "in vitro" proliferation of L-CFU is dependent upon the addition of exogenous growth factors. However, it has been observed that leukaemic progenitor cells frequently display a certain degree of autonomous proliferation. In order to quantify the "in vitro" behaviour of L-CFU, we have explored 3 parameters: 1) plating efficiency (PE); 2) autonomous growth (AG); and 3) autonomous proliferative index (API) which was calculated as AG divided by PE and we have correlated them with other clinico-biological data. According to the FAB classification we could observe that patients with M3 subtype showed an higher PE than other AML subgroups and a significantly lower API. Regarding CD34 expression we observed that AG was enhanced in CD34+ cases and also in those showing a higher rh123 elimination. In order to determine whether PE could condition clinical evolution, we analysed this parameter in a large series of patients but failed to demonstrate any relationship. By contrast, we observed that patients who displayed a higher API showed a shorter survival than patients with lower API (18% vs 48% surviving at 3 years). We have also shown that abnormalities in the CFU-GM growth pattern could be associated with risk the of relapse in AML patients; a switch from normal to abnormal "in vitro" growth should alert us. But for the assessment of the real value of these analyses sequential follow-up studies are mandatory. In summary, cell culture studies contribute not only to a better understanding of leukaemic hematopoiesis but may also contribute to better disease monitoring.
Immunophenotypic and DNA content characteristics of plasma cells in multiple myeloma and monoclonal gammopathy of undetermined significance.
In the present paper we review the immunophenotypic characteristics of plasma cells (PC) and the PC DNA contents from multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS), and its value for the differential diagnosis between both entities. The strong reactivity for CD38 and the positivity for CD138 are the two best markers for identifying PC. Myelomatous PC display an heterogeneous phenotype consistent with the fact that the neoplastic clone is able to undergo a certain degree of differentiation. In addition, PC from MM patients usually lack surface expression of B-cell associated antigens and frequently display reactivity for markers which are not restricted to the B-cell lineage. In MGUS patients, two clearly defined and distinct PC subpopulations can be identified. One of these PC subpopulations shows phenotypic characteristics identical to those of normal PC, including a very strong reactivity for the CD38 antigen, intermediate/low light scatter characteristics and positivity for CD19, in the absence of CD56, and corresponds to the residual normal bone marrow PC. The second PC subpopulation shows an immunophenotype similar to that of myelomatous PC, characterized by a slightly lower reactivity for CD38 and strong CD56 expression, on the absence of positivity for CD19, these PC corresponding to the clonal counterpart. Using a simultaneous staining for PC and DNA, around 60% of MM and 73% of MGUS patients display DNA aneuploidy, the majority of them being hyperdiploid. However, in contrast to MM patients, in MGUS patients two clearly different PC subsets can be discriminated in most cases (73%): a diploid and an aneuploid (hyperdiploid) subset, corresponding to normal and clonal PC, respectively. Upon comparing hyperdiploid with diploid patients in MM, the former display a better prognosis, in line with the higher incidence of DNA hyperdiploidy in MGUS. A clear correlation between the percentage of S-phase PC and several prognosis features of MM has been found. In spite of these findings, no significant differences in the percentage of pathological S-phase PC are detected between MM and MGUS patients. Regarding the differential diagnosis between MGUS and MM, multivariate analysis shows that the ratio between the number of clonal and normal residual PC is the best single parameter.
Intermediate-term outcome of mitral reconstruction in cardiomyopathy.
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[Transesophageal echocardiography in the operating room].
The need to optimize cardiac surgery performance combined with the capability that intraoperative transesophageal echocardiography (ETE) has to evaluate the surgical results in real time, without invading the operative field and with an image quality as good as epicardial echo, have led to the increasing use of this tool in the surgical setting. After describing the historical evolution and defining the leading indications to perform intraoperative echocardiography, the author reports his experience with intraoperative TEE. The echocardiographic evaluation of the surgically repaired mitral valve deserves particular attention as it represents the leading reason to perform intraoperative TEE in his experience. Between January 91 and January 98, 116 intraoperative TEE were performed, most of them (65%) in patients submitted to valvular surgery, particularly for the evaluation of reparative mitral valve surgery results (34%). The results of conservative surgery was considered satisfactory in 33 patients (82%) ad unsatisfactory in six (15%). These patients have had a second run of cardiopulmonary by-pass and a mitral prosthesis was implanted in all of them. Looking ahead, the author concludes with the importance that three-dimensional and myocardial contrast echocardiography will have on broadening the indications to perform intraoperative TEE.
Cardiac papillary fibroelastoma of a mitral valve chordae revealed by stroke.
We report the case of a young male patient referred to our hospital after having a stroke due to a papillary fibroelastoma arising from a mitral valve chorda. The tumor was identified by two-dimensional echocardiography and was treated by surgery with preservation of valve integrity. Cardiac papillary fibroelastoma as an uncommon source of cerebral emboli is discussed.
[Severe ventricular dysfunction. When should is surgery not indicated?].
The decision to operate in the presence of severe ventricular dysfunction is one of the most difficult medical judgements because ventricular dysfunction is, as we know, the leading risk factor for morbidity and mortality in cardiac surgery. However, despite the greater surgical risk in some pathologies, the patients with severe cardiac dysfunction are those who will most likely benefit from surgery when we compare medical and surgical survival curves. Although ejection fraction is the parameter usually used to quantify ventricular systolic function and to stratify patients according to risk, we should not ignore the limitations of this parameter in the evaluation of myocardial function. Therefore, besides ejection fraction, other criteria should be considered in the process of patient selection for surgery. Taking these facts into consideration, the author seeks to establish criteria for different cardiac pathologies for the surgical treatment of patients with severe left ventricular dysfunction.
Determinants of survival after aortic valve replacement.
The aim of this study to was evaluate the surgical results of Aortic Valve Replacement (AVR) and to identify the predictive variables associated to risk. A total of 650 consecutive patients underwent isolated AVR at the Thoracic Surgery Centre, S. João Hospital, Oporto, between January 1976 and December 1996. There were 29 (4.5%) early operative deaths and 108 follow-up deaths (64 cardiac and 44 non cardiac), which represents a linearized rate of 2.3% patients per year. The 5, 10 and 15 year cumulative survival rates for the 650 patients were 85 +/- 3%; 76 +/- 4.1% and 64 +/- 6.6, respectively. According to data in the literature, six preoperative variable and four operative variables were selected to be tested for association to risk. Multivariate analysis identified advanced age and the year of operation as the most important predictors of mortality followed by the type of the prosthesis (the mechanical valves performing better than the biological ones) and the prosthetic valve size (the small prosthesis performing worse than the others). We concluded that AVR is currently a low risk procedure at our Centre. The patient's age emerges as the main risk factor for overall mortality; a mechanical prosthesis should be preferred, at least before the age of 60, and prostheses with a ring size below 21-mm should be avoided.
Coping with ill health in a rickshaw puller's household in Chittagong, Bangladesh.
The correlation between poverty and ill-health is undeniably strong. Ill-health reduces the earning capacity, and increases the risk of families with ill members to drift down the social and economic ladder. In this article, we present a simulation model of how a poor rickshaw puller in Bangladesh copes with illness, in particular tuberculosis (TB). We first analyze the various coping mechanisms that are set in motion when he starts to suffer from tuberculosis; the impact on household assets, income and food intake will be studied. The simulation model is then used to analyse the effects on his household of a specific health intervention, namely the Directly Observer Treatment Short Course (DOTS) treatment. It shows that DOTS offers positive improvements of the overall well-being of the household by restoring the working capacity of the rickshaw puller in one treatment course and minimizing lost income. Assets and food consumption would be preserved significantly more in the presence of DOTS, rendering the household both financially and physically less vulnerable. The probability of death of the sick rickshaw puller is also significantly reduced, improving household's welfare over the long run.