Biomedical subjects
Publications and source records attributed to B Colombo.
An electrophoretic fast-moving hemoglobin was found in a Cuban family of Spanish descent. Structural studies demonstrated a replacement of arginine by glycine at alpha 141(HC3). This change is not associated with clinical symptoms, although the substitution is in one of the residues involved in the stabilization of the deoxy form of the hemoglobin molecule.
Explore the source record for details and available documents.
Haemoglobin J Cubujuqui (alpha2141(HC3)Arg replaced by Ser beta2) was found during a screening for abnormal haemoglobins carried out in Costa Rica. This variant is clinically silent, although its substitution is in one of the residues involved in the stabilization of the deoxy form of the haemoglobin molecule.
Haemoglobin J Guantanamo (alpha 2 beta 2 128 (H6) Ala replaced by Asp) was found during a screening from abnormal haemoglobins in three members of a Cuban family, of negro ancestry. The substitution in this variant is located at the alpha 1 beta 1 contact. This explains the slight instability and the mild haemolytic anaemia and morphological abnormalities found in the carriers of this variant. The instability of haemoglobin J Guantanamo indicates that the presence of Asp at the position beta-128 (H6) weakens the alpha 1 beta 1 contact.
Explore the source record for details and available documents.
During a screening programme for abnormal haemoglobins in Habana, one case of Hb Porto Alegre was found in 23 000 cases analysed. The ability of this variant to polymerise in vitro and the absence of clinical features in the carriers have been confirmed. These observations are now explained by the findings of high levels of glutathione in the red cells of subjects heterozygous for Hb Porto Alegre: it is suggested that the increase of glutathione is responsible for the absence of in vivo polymerisation and accounts for the lack of clinical symptoms.
Explore the source record for details and available documents.
Eighteen patients with myasthenia gravis, second-stage (A or B) according to Ossermann and Genkins, and of young age, were examined as outpatients from the cardiological point of view. Clinical and radiological examination of the heart and large vessels revealed no pathological features. Electrocardiographic abnormalities (including one case of ventricular preexcitation syndrome and one of subepicardial ischemia) were detected in three patients (16,6%). Among the various left ventricular systolic time intervals, only the deformation time was somewhat off normal limits in some cases, but the difference was not statistically significant. In over one-third of the cases, conversely, the kinetocardiogram revealed paradoxical systolic outward movements, indicative of myocardial dyskinesis or dissinergy. The essential normality of systolic time intervals in the presence of manifest abnormalities of the kinetocardiographic curve may be explained by the smallness of hypokinetic or dyskinetic areas, whereby the ejection fraction was not reduced. In general, the ECG and kinetocardiographic tracings showed no tendency to change under the effect of orally administered pyridostigmine.
Haemoglobin F (Hb F) levels were determined in 209 full-term newborn babies or infants of different ages ranging from birth to 11 months. A follow-up study of the disappearance of Hb F after birth was carried out on 25 premature babies; they were followed periodically from birth until 8 months. The results obtained in both samples show that Hb F levels remain constant after birth for periods varying from about 15 d in at term babies to about 40 d in premature babies; a linear decrease follows in both cases. The initial plateau is a finding contrary to what has been reported. A possible model for the phenomenon is discussed in terms of haemoglobin genes and ontogenetic differentiation.
The frequency of alpha-thalassaemia has been determined by the analysis of Hb Barts in 650 newborns; 4.46% of them showed high levels of Hb Barts. The incidence of newborns with different levels of Hb Barts (1-2, 5 and 25%, respectively) and the frequency of the alpha-thalassaemia genes are also given.
Gene frequencies of several red cell and serum gentic markers were determined in the three main racial groups--whites, mulattoes and Negroes--of the Cuban population. The results were used to estimate the relative contribution of Caucasian and Negro genes to the genetic makeup of these three groups and to calculate the frequencies of these genes in the general Cuban population.
The significance and importance of investigation of the synovial fluid enzymes in the main arthropathies are explanined. Tables are given for the main enzymes studied, the cell compartments of origin, and data for their values in rheumatic diseases (as reported in the literature). Stress is laid on the importance of enzymes belonging to the lysosomial compartment, both in the pathogenesis of the underlying inflammation and in the relation to anatomopathological lesions in the joints. Attention is directed to the most widely accepted hypotheses. These ten to see enzymes increases in breakdown of condrocytes, as inflammatory arthritis attributable to synoviocytes and leukocytes. A personal opinion based on prior research is also presented. Further work in this sector is urged a mean of learning more about the pathology of rheumatic diseases.
The frequencies of the Gd-A, Gd-A- and Gd-B alleles have been estimated in a random sample of 455 female and 405 male high school students from Habana. The estimates of the Negro and Caucasian relative contributions to the present genetic make-up of the Habana population, based on these gene frequencies, are 0.20 and 0.80 respectively.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.