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Biomedical subjects

M Arias

Publications and source records attributed to M Arias.

At least 127 records · Page 7Linked to original sources
PubMed1999

Relationship between radiologic morphology of the bone lengthening formation and its complications.

The objective was to study the different types of lengthened bone regeneration and their development during the various phases of the process to correlate them with patient factors and the surgical technique used, and to establish a possible relation between the development of the bone lengthening formation and the problems or complications. The authors studied the radiographs of a random group of 55 patients taken at three points during the course of treatment. The callus was classified with regard to its transverse diameter and the presence or absence of hypodense areas. The overall callus type was significantly influenced by the etiology, the osteotomy site, and the percentage lengthened. The percentage by which the limb was lengthened at the beginning of the process influences the overall morphology of the callus. Poor callus had been lengthened the most, atrophic callus the least. There was a correlation between the morphology of the overall callus at the end of treatment and the percentage lengthened, and between the percentage lengthened and the presence of bands at the end of treatment. The authors also found a significant correlation between age and the appearance of bands at the end of distraction. A central band was found among younger patients. The type of osteotomy affected the overall callus at the end of distraction and at the end of treatment and also influenced the transverse diameter. All the elongations with poor bone formation at the end of treatment were found to have undergone a diaphyseal osteotomy. The most common complication at the first follow-up and at the end of distraction was angulation. The diameter of the callus and the presence of bands at the end of treatment were significantly related to the complications. Fracture occurred in the first 2 weeks after removal of the external fixator in 88% of cases and in the third and fourth week in the rest. However, the segment had no significant influence on the appearance of complications. Lengthened callus with incomplete trabecular formations and hypodense areas at the end of the treatment has a high risk of fracture at the end of treatment. Callus with axial deviation, hypodense areas, or an insufficient transverse diameter during the lengthening procedure must be manipulated so that it reaches the maturing phase in better condition.

Adolescent↗
PubMed1999

[Cervical ectopic thymus].

We present a case of ectopic thymus in an eight month old male baby, with a right lateral tumor of the neck. Ectopic thymus is a pathology rarely observed, its embryogenesis could explain its cervical localization. X Ray, ultrasonography, IRM, esophagoscophy and laryngoscophy may be helpful in the differential diagnosis with other tumors of the neck. Due to the fact that cystic lesions and neoplasis developments take place, the chosen treatment is the complete chirurgical extirpation. But at the absence of symptoms, no treatments is advisable because eventually the thymus spontaneously involutionates.

Choristoma↗
PubMed1998

Steroid hormone regulation of cytokine secretion by proteolipid protein-specific CD4+ T cell clones isolated from multiple sclerosis patients and normal control subjects.

Steroid hormones have long been known to modulate immune function, and recent studies indicate that one of the means by which they do so involves effects on the secretion of immunoregulatory cytokines. Our laboratory has found recently that estradiol (E2) selectively modifies cytokine secretion in proteolipid protein (PLP)-specific, CD4+ T cell clones isolated from patients with the demyelinating disease, multiple sclerosis, and from normal control subjects. The data suggest that E2 may play a role in regulating the balance between pro- and antiinflammatory conditions, especially at concentrations typical of pregnancy. To determine whether other pregnancy-associated steroid hormones are capable of similar activity, we expanded our testing to include estrone (E1), estriol (E3), progesterone, and dexamethasone. The results indicate that E1 and E3 enhance secretion of Ag- or anti-CD3-stimulated IL-10 and IFN-gamma in dose-dependent fashion, almost identical to that of E2. The effect on IL-10 was more potent than occurred with IFN-gamma. In addition, E1 and E3, like E2, had a biphasic effect on TNF-alphabeta secretion, with low concentrations stimulatory, and high doses inhibitory. None of the estrogens influenced IL-4 or TGF-beta secretion. Progesterone enhanced secretion of IL-4, without affecting any other tested cytokine. Finally, dexamethasone induced TGF-beta secretion, but inhibited IFN-gamma and TNF-alphabeta. This differential effect of steroid hormones on the secretion of cytokines by CD4+ human T cell clones is consistent with the possibility that, collectively, they promote antiinflammatory conditions at high concentrations typical of pregnancy.

CD4-Positive T-Lymphocytes↗
PubMed1998

[Diagnostic usefulness of glutamic acid decarboxylase antibodies in stiff-man syndrome].

Stiff-man syndrome (SMS) is a rare neurological disorder characterized by progressive rigidity of the axial musculature with superimposed spasms. Frequently, SMS remains undiagnosed for prolonged periods or the patients are diagnosed of a primary psychiatric disorder. 60% of the SMS patients harbor GAD-autoantibodies (GAD-Ab). We have analyzed the diagnostic value of GAD-Ab in a syndrome whose clinical expression is not well known, but its diagnosis is performed by clinical criteria. Five patients were studied following the established clinical criteria for diagnosis of SMS. GAD-Ab were analyzed by radioimmunoassay (RIA) and immunohistochemistry, and confirmed by immunoblot. The GAD-Ab titers were compared with those of 49 patients with insulin-dependent diabetes mellitus (IDDM), 322 with other neurological disorders, 14 non-IDDM first-degree relatives of IDDM patients with antibodies anti-islet cells and 91 normal subjects. Three patients fulfilled all clinical criteria (typical SMS). Unilateral limb symptoms alone, and acute onset with rapid progression involving the distal limb muscles constituted the atypical features of SMS in the remaining 2 patients. The 5 patients presented several serum organ-specific autoantibodies. All but one also presented autoimmune diseases. By RIA, GAD-Ab titers from all patients were elevated (mean: 24,532 +/- 26,892 U/ml) and significantly higher than the titers of IDDM patients without neurological disorders (mean: 48 +/- 112 U/ml) (p < 0.0001). GAD-Ab were absent in the non-SMS patients and in normal subjects. These findings suggest that clinical expression of SMS is more extensive than that recognized by the established criteria. GAD-Ab are helpful to define the clinical spectrum of SMS.

Aged↗
PubMed1998

A Phase II trial of neoadjuvant methotrexate, vinblastine, doxorubicin, and cisplatin in the treatment of patients with locally advanced breast carcinoma.

BACKGROUND: Traditionally, primary surgical therapy is considered unsuitable for the treatment of patients with locally advanced breast carcinoma (LABC). Multiple reports have documented the efficacy of primary chemotherapy in this group of patients. The purpose of this study was to investigate the efficacy of a multimodality treatment program in reducing distant and local disease relapses in patients with LABC. METHODS: Fifty-five patients with large operable or inoperable Stage III breast carcinoma, median tumor greatest dimension 7 x 8 cm, were treated with neoadjuvant MVAC (methotrexate, vinblastine, doxorubicin, and cisplatin) to achieve maximum clinical response, followed by modified radical mastectomy, adjuvant MVAC for six courses, and chest wall radiation. Of these patients, 37 had Stage IIIA disease and 18 had Stage IIIB or inflammatory breast carcinoma. RESULTS: Forty-nine patients achieved overall responses to the neoadjuvant chemotherapy, including 16 complete clinical remissions. Histopathologic evaluation was performed for all patients; nine were pathologically free of disease and six had residual intraductal carcinoma only. After a median follow-up of 47 months (range, 8-76 months), 24 patients had relapsed: 6 locoregional and distant, and 18 distant only. The median disease free and overall survival have not been reached; the 5-year disease free and overall survival rates are 51% and 63%, respectively. The number of lymph nodes with metastases was found to be an independent predictor of relapse in univariate and multivariate analyses. CONCLUSIONS: This multidisciplinary approach produced an excellent local control rate and a respectable 5-year distant relapse free rate. Axillary lymphadenectomy after primary chemotherapy provides crucial prognostic information, which can be important in planning multimodality treatment of patients with LABC.

Adult↗
PubMed1998

Effect of serum phosphate on parathyroid hormone secretion during hemodialysis.

BACKGROUND: Recent studies have demonstrated that a high concentration of phosphate directly stimulates parathyroid hormone (PTH) secretion. High serum levels of phosphate are usually observed in patients with end-stage renal disease. The aim of the present study was to evaluate whether serum phosphate concentration had an acute effect on PTH secretion in hemodialysis patients. The levels of serum phosphate were manipulated during the hemodialysis session by using a phosphate free dialysate or a dialysate with a high content of phosphate. METHODS: Ten stable hemodialysis patients with PTH values above 300 pg/ml were included in the study. A PTH-calcium curve was obtained during both high phosphate and phosphate free hemodialysis. RESULTS: The serum phosphate concentration remained high (2.17 +/- 0.18 mM) throughout the high phosphate hemodialysis and decreased progressively to normal levels (1.02 +/- 0.06 mM) during the phosphate free hemodialysis. The serum PTH levels at maximal inhibition by hypercalcemia (minimal PTH) were greater during the high phosphate than the phosphate free hemodialysis (413 +/- 79 vs. 318 +/- 76 pg/ml, P < 0.003). In all patients the values of minimum PTH were greater during the high phosphorus than the phosphorus free hemodialysis. The values of maximally stimulated PTH during hypocalcemia and the set point of the PTH-calcium curve were similar during the high phosphate and the phosphate free hemodialysis. CONCLUSION: The maintenance of high serum phosphorus levels during hemodialysis prevented, in part, the inhibition of PTH secretion by calcium, which strongly suggests that in hemodialysis patients high serum phosphate contributes directly to the elevation of PTH levels despite normal or high serum calcium concentration.

Adult↗
PubMed1998

Diminished adherence and/or ingestion of virulent Mycobacterium tuberculosis by monocyte-derived macrophages from patients with tuberculosis.

The interaction between the macrophage and Mycobacterium tuberculosis is mediated by a variety of macrophage membrane-associated proteins. Complement receptors have been implicated in the adherence of M. tuberculosis to macrophages. In the present work, the adherence and/or ingestion of M. tuberculosis H37Rv to human monocyte-derived macrophages (MDM) from patients with tuberculosis (TB) and healthy controls was measured by microscopical examination, [3H]uracil incorporation, and CFU. The adherence and/or ingestion was enhanced by fresh serum and inhibited by heat inactivation, EDTA treatment, and anti-CR1 and anti-CR3 antibodies. Comparison of MDM from TB patients and healthy controls showed that the former exhibited a significantly decreased capacity to adhere and/or ingest M. tuberculosis, as determined by the number of CFU and 3H incorporation. The expression of CR1 (CD35) and CR3 (CD11b/CD18) on MDM from TB patients and healthy controls, as determined by flow cytometry, did not show significant differences. These results suggest that the lower ingestion of M. tuberculosis by MDM from TB patients is not due to defects in complement receptors, and therefore, there might be other molecules involved in the adherence and/or ingestion process that render MDM from TB patients ingest less mycobacteria than those from healthy controls.

Bacterial Adhesion↗
PubMed1998

[Clinical pseudo-peripheral presentation of cerebral lesions].

Small size cerebral lesions, located strategically, can determine the presence of sensitive and motor signs limited to a part of an extremity, clinically suggesting peripheral nervous system affectation, determining erroneous diagnostic and therapeutic decisions. We present 5 patients initially diagnosed of peripheral nervous system pathology, which were finally diagnosed of cerebral lesions (2 lacunar infarcts, multiple sclerosis, progressive multifocal leucoencephalopaty, multicentric astrocytoma). In all, clinical examination disclosed incongruous distribution of the sensitive manifestations and myotatic reflexes were present. CT studies were normal in three patients whereas MRI showed lesions in all cases. Lesions were smaller than 1.5 cm in diameter (greater in the case of multicentric astrocytoma), and were subcortically located in the opposite cerebral hemisphere to the affected extremity. Sensitivomotor signs restricted to an extremity not concordant with a nervous or radicular distribution and with presentation of myotatic reflexes, make it necessary to look for a central nervous system lesion. Lesion will be located in the opposite cerebral hemisphere and MRI will be the elective complementary exam.

Adult↗
PubMed1998

[Long chronic course of hemiparkinson-plus with l-dopa maintained response].

UNLABELLED: OBJECTIVE AND CLINICAL CASE: We describe and present a video film of a patient with a hemiparkinsonian illness associated with hemidystonia and pyramidalism, which responded to continuous L-Dopa treatment for twenty years, with no fluctuation or deterioration at the end of the dose-effect. CT and MR studies were normal. CONCLUSIONS: The characteristics of this case with probable static unilateral dysfunction, basically presynaptic, of the nigrostriate via, make it reasonable to include it in the hemiparkinson-hemiatrophy group.

Aged↗
PubMed1998

[From writer's cramp to butcher's spasms: a case of interprofessional dystonia].

INTRODUCTION: Occupational or professional dystonia is a focal motor dystonic disorder which affect motor programs necessaries for the exercise of the patient's profession. Clinical case. A patient with writer's cramp in the childhood presented at the age of 22 years a new dystonia, which we name 'butcher's spasm', giving rise to a laboral incapacity. Neurological exam was normal except for right arm distal (writer's cramp) and proximal dystonias (butcher's cramp), with intentional tremor in the upper extremities. We classified, after complementary exams, the disease as idiopathic. CONCLUSIONS: Idiopathic focal dystonias can progress to segmentary or multifocal dystonias, and, in exceptional cases as ours, can interfere with two different professional activities.

Adult↗
PubMed1997

Inhibition of virulent Mycobacterium tuberculosis by Bcg(r) and Bcg(s) macrophages correlates with nitric oxide production.

The Nramp1 gene controls macrophage resistance or susceptibility to several intracellular microorganisms; however, there is conflicting evidence regarding its role during infection with virulent Mycobacterium tuberculosis. Nitric oxide (NO) is a potent antimycobacterial agent produced by macrophages, which is also regulated by Nramp1. The in vitro ability of B10R (resistant) and B10S (susceptible) murine macrophages to inhibit M. tuberculosis H37Rv and to produce NO in response to infection and interferon-gamma (IFN-gamma) was compared. Infected B10R macrophages inhibited [3H]uracil incorporation by M. tuberculosis and produced higher amounts of NO than did B10S macrophages. IFN-gamma increased the inhibitory activity of both cells. Inhibition of M. tuberculosis by IFN-gamma-activated B10R macrophages was reversed by N(G)-monomethyl-L-arginine (N(G)MMA). L-arginine restored NO production and increased the antimycobacterial activity by IFN-gamma-stimulated N(G)MMA-treated macrophages. The Bcg/Nramp1 gene may regulate macrophage resistance or susceptibility to virulent M. tuberculosis by a differential capability of these cells to produce NO.

Animals↗
PubMed1997

Description of a project for the production and evaluation of oxygen-carrying hemosubstitutes.

Scarce availability and risk of transmission of infections and diseases (HIV, hepatitis B, Chagas' disease) limit the use and benefits of homologous blood transfusions for surgical purposes. Recent trials of perfluorocarbon-based hemosubstitutes (PFC-HSs) in experimental cardiopulmonary bypass (CPB) have demonstrated their ability to improve brain oxygenation, as compared with conventional crystalloid priming solutions. The objective of the project described here is to test different formulations of PFC-HSs and optimize their formulation and dosage for use in CPB. The project includes: (1) study the feasibility of implementing a laboratory for small scale production of PFC-HSs; (2) evaluate the efficacy of use of PFC-HSs in an animal model of CPB; and (3) evaluate the safety of use of PFC-HSs in an animal model of hemorrhagic shock. Several in-house PFC-HSs and outside PFC-HSs are being evaluated. The current state of the project is: (1) the feasibility study has been completed and several PFCs, emulsifiers and surfactants are being tested; (2) and (3) the animal models have been implemented are being used to test in-house and outside PFC-HSs as priming solutions in CPB and reinfusion fluids in hemorrhagic shock respectively. Some preliminary results are presented.

Animals↗
PubMed1996

Primary amyloidosis presenting as renal infarction.

We report a case of primary amyloidosis affecting the kidney and presenting as a renal infarction on computed tomography and ultrasound examination. To our knowledge, it is the first case in the radio-logical literature with these imaging characteristics.

Amyloidosis↗