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Biomedical subjects

F Cervantes

Publications and source records attributed to F Cervantes.

At least 199 records · Page 11Linked to original sources
PubMed1982

Prognostic significance of cytogenetical studies in chronic granulocytic leukaemia.

In a series of 121 patients with chronic granulocytic leukaemia (CGL) the frequence and prognostic significance of two cytogenetical features (absence of Ph'-chromosome and presence of Ph'-mosaicism) were studied. 13% of the patients were Ph'-negative, these patients showing a shorter survival than the Ph'-positive ones (P less than 0.005). 23 instances of Ph'-mosaicism were found (22.5%). This feature was observed either at diagnosis or after treatment, and irrespective of the patient's being in chronic or blastic phase of CGL, but in no case later than 2 years from diagnosis of the disease. Ph'-mosaicism patients vs the remainder of the Ph'-positive group were compared for survival, and no difference was found. The lack of prognostic significance of Ph'-mosaicism was evident regardless of the latter feature being detected at diagnosis or after treatment.

Adolescent↗
PubMed1982

Tumour lysis syndrome with hypocälcaemia in accelerated chronic granulocytic leukaemia.

Tumour lysis syndrome is a well-known complication of lymphoid malignancies, but it has rarely been described in myeloproliferative disorders. A patient is reported with myeloblastic type of accelerated chronic granulocytic leukaemia who developed a tumour lysis syndrome following intensive chemotherapy. The most prominent manifestation of such a syndrome was hypocalcaemia, which was associated with other biochemical alterations, including hyperphosphataemia, hyperuricaemia and renal failure.

Adult↗
PubMed1982

A multivariate analysis of prognostic factors in chronic myeloid leukemia.

The prognostic value of different clinical and laboratory findings at diagnosis of chronic myeloid leukemia (CML) was analyzed in a series of 121 cytogenetically studied patients. From the univariate and multivariate analysis of the whole series it was apparent that the minority of Ph1-negative patients (11.5%) could be considered as a poor prognosis group. The analysis was then restricted to the Ph1-positive patients. From a multivariate survival analysis (Cox's regression model) of the latter group the following poor prognosis factors emerged: splenomegaly, hepatomegaly, presence of erythroid precursors in peripheral blood, and bone marrow myeloblasts over 5%. From the contribution of each one of these factors to the regression model, a clinical staging of Ph1-positive CML was derived: stage I (low risk, 32% of patients), including patients with one or no factors; stage II (intermediate risk, 38%), including cases with two factors; and stage III (high risk, 30%), including patients with three or four factors. The difference in survival of the patients at different stages was highly significant (p less than 0.001).

Adolescent↗
PubMed1981

Multiple myeloma in primary biliary cirrhosis.

A patient who had primary biliary cirrhosis and, simultaneously, multiple myeloma (IgG, lambda) is reported. In chronic liver diseases, polyclonal hypergammaglobulinaemia is common, monoclonal gammopathies have also been found in rare instances, being attributed to chronic antigenic stimulation of the reticuloendothelial system by antigens from the intestinal flora. The mechanisms (as chronic antigenic stimulation, immunologic disturbances and granulomata formation) which apply to explain the development of monoclonal gammopathies in other conditions are also found in primary biliary cirrhosis. It is postulated that, in this disease, the development of multiple myeloma could be not merely coincidental but also the result of chronic stimulation of the reticuloendothelial system.

Female↗
PubMed1980

Mathematical models of synaptic plasticity: I. Posttetanic potentiation.

A mathematical model of post-tetanic potentiation is proposed. The model uses differential equations and is based upon physiological postulates of the electrical, metabolic, and neuroendocrine activities that are related to synaptic connectivity. These activities may modify some important parameters in synaptic function. In the proposed model these parameters are restricted to the presynapse in view of the physiological evidence indicating that posttetanic potentiation is probably due to presynaptic mechanisms. The model takes into consideration the size of the transmitter pool available for release, the mobilization of transmitter from and to this pool, and the fraction of transmitter released. Based upon the above postulates, we have simulated different phases of the phenomenon of posttetanic potentiation, and we have presented the results of several preparations in which this event has been studied. This work represents a successful attempt to reproduce the dynamics of posttetanic potentiation based upon physiological results with a mathematical model.

Calcium↗
PubMed1980

Mathematical model of synaptic plasticity: II. Habituation.

A mathematical model of the phenomenon of habituation as a homosynaptic depression of the amount of transmitter release is proposed. The model is based on the physiological studies of habituation in invertebrates and in the spinal cord of vertebrates, where a single synapse has been isolated and some of the physiological mechanisms of this process have been elucidated. The model simulates the following properties of habituation: (1) reduced amount of transmitter release attributed to a repetitive stimulus through changes in the membrane permeability to Ca2+ ions; (2) spontaneous recovery by rest; (3) the amplitude and frequency dependence of habituation; (4) modulation of habituation: sensitization, through an increase in membrane Ca2+ permeability, and presynaptic inhibition, through a reduced depolarization of the physiological stimulus; (5) long-term habituation attributed to repetitive trials of habituation and spontaneous recovery.

Animals↗
PubMed1980

Mathematical model of synaptic plasticity: III. Heterosynaptic changes.

A mathematical model, using differential equations, of heterosynaptic plasticity is proposed. The model is based on physiological studies of invertebrates in which nonspecific conditioning, such as sensitization and heterosynaptic inhibition, starts to be elucidated and behavioral studies of classical and instrumental conditioning, which we postulate to have the same mechanisms as those found in nonspecific conditioning. The model permits us to simulate the following heterosynaptic changes: sensitization, heterosynaptic inhibition, classical and instrumental conditioning--including short- and long-term memory--extinction and recuperation--spontaneously and by stimulation.

Animals↗
PubMed1980

Low-dose vincristine in the treatment of corticosteroid-refractory idiopathic thrombocytopenic purpura (ITP) in non-splenectomized patients.

Eight non-splenectomized patients with corticosteroid-refractory idiopathic thrombocytopenic purpura (ITP) were treated with low-dose vincristine (1 mg/week up to a total dose of 4 mg). Complete remission was achieved in 2 cases and partial remission in 3. Bleeding stopped in one patient who failed to remit. No statistical relationship was found between the response to vincristine and the duration of the disease or the corticosteroid-therapy. Side effects were only observed in one patient. By comparing these results with those reported in the literature, it can be inferred that low-dose vincristine may be useful in the management of corticosteroid-refractory ITP.

Adolescent↗
PubMed1980

Thrombocytosis in quiescent chronic granulocytic leukaemia after vincristine and 6-mercaptopurine therapy.

In an attempt to retard the appearance of blastic transformation 11 patients recently diagnosed with chronic granulocytic leukaemia were given courses of vincristine and 6-mercaptopurine after stabilization of the disease by busulfan. In 4 of the patients a marked thrombocytosis developed shortly after the administration of such courses. When we compared the clinical and biological features at the moment of diagnosis, the patients in whom thrombocytosis developed after vincristine and 6-mercaptopurine courses showed higher platelet counts and a smaller spleen size than the other ones, although no statistical significance was reached. A possible thrombocytopoietic effect of vincristine is discussed.

Adolescent↗