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Biomedical subjects

E Santos

Publications and source records attributed to E Santos.

At least 145 records · Page 8Linked to original sources
PubMed1981

Specific suppressor cells and immune response to host antigens in long-term human allogeneic marrow recipients: implications for the mechanisms of graft-host tolerance and chronic graft-versus-host disease.

After marrow grafting from HLA-identical siblings, anti-host immune reactivity and suppressor activity were examined in long-term patients with and without C-GVHD. Lymphocytes (of donor origin) from 17 of 32 patients with C-GVHD showed MLR to non-HLA antigens of stored host lymphocytes, and lymphocytes from 8 of 21 patients with C-GVHD exhibited cytotoxicity to host skin fibroblasts. Lymphocytes from only 2 of 15 patients without C-GVHD, however, showed significant MLR to host lymphocytes and none of 16 had cytotoxicity to host fibroblasts. Suppressor activities differed in the two patient groups. Patients without C-GVHD had circulating suppressor cells that specifically inhibited donor MLR to TNP-host lymphocytes but not to TNP-donor, TNP-unrelated and unmodified unrelated lymphocytes. On the other hand, patients with C-GVHD had predominantly suppressor cells that inhibited donor MLR to TNP-unrelated and unmodified unrelated lymphocytes. These findings indicate that anti-host immune reactivity in the absence of specific suppressor cells plays a role in C-GVHD, and that graft-host tolerance in the stable chimeras may be maintained by specific suppressor cells.

Acute Disease↗
PubMed1979

Nonspecific suppressor cells in patients with chronic graft-vs-host disease after marrow grafting.

Forty-four human long-term survivors after marrow transplantation for aplastic anemia or hematologic malignancy were studied for the presence of circulating nonspecific suppressor cells. Twenty-two of the patients were healthy and 22 had mild to moderately severe chronic graft-vs-host disease (GVHD). Patient mononuclear cells (of donor origin) were tested for their ability to suppress the responses of lymphocytes obtained from the respective marrow donors to alloantigens in mixed leukocyte culture (MLC) and/or to concanavalin A (Con A). Tests were carried out between 199 and 2393 (median 376) days after transplantation. Cells from only 1 of 22 patients without chronic GVHD showed suppression of donor cell blastogeneis responses. In contrast, cells from 11 of 22 patients with chronic GVHD showed more than 30% suppression of donor cell responses in MLC and/or to Con A. The finding of suppressor cells was not related to the time of testing after grafting nor to immmunosuppressive therapy. Nonspecific suppressor activity was abrogated by irradiation with 1600 rads in vitro in five of six cases tested. Nonspecific suppressor cells may be one explanation for the severe combined immunodeficiency and the recurrent infectious complications characteristic of patients with chronic GVHD.

Bone Marrow Transplantation↗
PubMed1978

The plasma membrane of Saccharomyces cerevisiae. Isolation and some properties.

The isolation of Saccharomyces cerevisiae plasma membrane was carried out after hypotonic lysis of yeast protoplasts treated with concanavalin A by two independent methods: a, at low speed centrifugation and b, at high speed centrifugation in a density gradient. Several techniques (electron microscopic, enzymic, tagging, etc.) were used to ascertain the degree of purification of the plasma membranes obtained. The low speed centrifugation technique as compared with the other method gave a higher yield of plasma membranes with a similar degree of purification. Analysis of the yeast plasma membrane of normally growing cells by sodium dodecyl sulphate polyacrylamide gel electrophoresis showed at least 25 polypeptide bands. Twelve glycoprotein bands were also found, and their apparent molecular weights were determined. Treatment of the protoplasts with cycloheximide resulted in a significant decrease in the carbohydrate and protein content of the plasma membrane. The electrophoretic pattern of the plasma membrane of cycloheximide-treated cells showed a redistribution of the relative amounts of each protein band and a drastic reduction in the number of Schiff-positive bands. The isoelectric point of the most abundant proteins was low (pI 4) or lower than expected from previous data. A large part of the mannosyl transferase activity found in the cell (80%) was associated with the internal membranes, the remaining activity (20%) was located in the plasma membrane preparation. Part of the mannosyl transferase activity of the cells is located at the plasma membrane surface. Invertase (an external mannoprotein) is found in both the plasma and internal membranes, and as the specific activity dropped significantly following cycloheximide treatment of the cells, it is suggested that these membranes systems are the structures for the glycosylation of a precursor invertase and its subsequent release into the periplasmic space. Other transferase found in the plasma membrane preparation transfers glucose residues from UDPglucose to a poly(alpha(1 leads to 4) polymer identified as glycogen.

Carbohydrates↗
PubMed1978

Inositol deficiency in yeast: metabolic, enzymatic and autoradiographic studies.

The addition of inositol to starved cells of Saccharomyces cerevisiae NCYC 86 resulted in an initiation of growth. Inositol was incorporated into phosphatidyl-inositol and after a lag period RNA was the first macromolecule with a rate of synthesis departing from the rate observed in deprived cells. Pulse chase experiments showed that inositol was first incorporated into phosphatidylinositol and later into more polar lipids. Finally it appeared to be excreted into the surrounding medium. When S. cerevisiae NCYC 86 was grown in suboptimal concentrations of inositol (0,5 microgram/ml), alterations in the level of some membrane-bound enzymatic activities were detected; these might reflect structural modifications of the cellular membranes due to a different composition of phospholipids. High-resolution autoradiography showed that inositol was probably first incorporated into internal membranes and later transferred to the plasma membrane. Analytical experiments carried out with inositol-deprived cells showed that inositol was released into the surrounding medium in that case. The unbalanced growth detected in S. cerevisiae NCYC 86 under inositol deprivation might be due to an abnormal functioning of the cell membranes as a consequence of the deficiency in inositol-containing phospholipids.

Autoradiography↗
PubMed1977

An ultrasonographic study of the persistence of buckle height three years after segmental sponge explants.

We studied a consecutive series of rhegmatogenous retinal detachments treated with segmental silicone sponge explants and cryotherapy, with or without drainage, approximately three years postoperatively by ultrasonography to determine the degree and persistence of the height of the buckle measuring 1.5 to 3 mm remained in all patienst examined clinically and ultrasonographically at three years or later. Five of these patients reexamined one year later demonstrated no loss of buckle height between the third and fourth postoperative years. By comparison, in a small group of patients examined early in their postoperative course (2.5 to 4 months), the buckles were only slightly higher than in the group studied at three years. Buckle height thus appeared to stabilize relatively quickly postoperatively and to persist at least three years. We believe encapsulation of the sponge by scar tissue must contribute to the long-term maintenance of buckle height.

Cryosurgery↗
PubMedDate not supplied

The waist and abdominoplasty.

Basing our work on ideal aesthetic features of the feminine figure and focusing our attention on the waist, we add several points to the abdominoplasty classification. We have carried out 150 abdomino plasties in the last 5 years: 60% of the patients presented with musculoponeurosis alterations, for whom plicature of the rectus abdominis and obliques with wide dissection was accomplished, and 40% with mainly fat excess at the flanks, on whom limited dissection and liposuction were performed. Our objective was to achieve an ideal waist for each patient.

Abdomen↗
PubMedDate not supplied

[Helical computerized tomography of the thorax in the diagnosis of unresolved chronic pulmonary thromboembolism].

We assessed the diagnostic usefulness of helical CT scan of the thorax in the setting of chronic thromboembolic pulmonary hypertension by prospectively comparing the results of helical CT scan to those of the pulmonary angiogram (gold standard). We studied 40 patients with diagnosis of pulmonary hypertension of diverse etiology (mean age: 40.7 +/- 12 y.o.; mean systolic pulmonary artery pressure: 91 +/- 33 mmHg)). Thirty of these patients fulfilled the diagnostic criteria of chronic thromboembolic pulmonary hypertension and the other ten were used as controls. Diagnosis in control patients included: primary pulmonary hypertension (4); patent ductus arteriosus (2); atrial septal defect (1); rheumatic valve disease (1); ischemic heart disease (1); and acute pulmonary embolism (1). Both helical CT scan and pulmonary angiogram were part of the routine diagnostic work up of these patients, and were, performed and interpreted almost simultaneously (within one week) by a different group of investigators in a blind manner. Only the diagnostic accuracy of the method regarding central (major arteries) vascular lesions was evaluated. Helical CT scan had an overall sensitivity of 100% (29/29), and a specificity of 91% (10/11). Positive predictive and negative predictive values were 96.6% (29/30) and 100% (10/10), respectively. Overall diagnostic accuracy was 97.5% (39/40). We conclude that helical CT scan of the thorax is an excellent alternative approach for the diagnosis of major arteries lesions in the setting of chronic thromboembolic pulmonary hypertension.

Adolescent↗
PubMedDate not supplied

[Diabetes and surgery I: effects on metabolic control and preoperative evaluation].

The management of diabetes mellitus before, during and after surgery represents a common challenge in clinical practice. Surgical stress promotes a sequence of hormonal changes that might cause devastating effects on the diabetic patient, and this stress depends on several factors, some of them predictable such as the type of surgical operation or the sort of anaesthesia which is applied. The glycemic control should be optimal in order to avoid the possible consequences derived from an inadequate metabolic control during the perioperative period. The knowledge of physiopathological processes involved in the effects of surgery and anaesthesia on metabolic control represents a key element for a successful management.

Diabetes Complications↗