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Biomedical subjects

J Rosa

Publications and source records attributed to J Rosa.

At least 163 records · Page 9Linked to original sources
PubMed1980

Fetal hemoglobin synthesis in culture of early erythroid precursors (BFU-E) from the blood of normal adults.

BFU-E from the blood of 14 normal adults have been grown by the plasma clot technique. The hemoglobins synthesized in burst colonies were purified from other proteins by affinity chromatography on Sepharose-haptoglobin. The radioactivity incorporated in the globin chains was estimated by CM-cellulose chromatography in urea. The number of bursts scored at the 14th day of culture fluctuated between 50-130 (average 86, s: 29) for 10(6) mononuclear plated cells. A constant reactivation of fetal hemoglobin was found (from 1.4% to 11%, mean value 5.8%, s:3.07), but was lower than previously described, mainly because of the highly selective purification of Hb. This reactivation of fetal hemoglobin was not dependent upon the concentration of erythropoietin (from 1 U/ml to 6 U/ml) nor on the purity of the erythropoietin preparations (from 6 U/mg of protein to 70 000U/mg of protein). In addition, the same subject exhibited a constant proportion of Hb F synthesized in culture over a period of time up to 6 months. A positive correlation exists between the proportion of Hb F in culture and that of F cells present in the blood, with the exception of two subjects. Such findings suggest that Hb F in culture is a characteristic of each individual and that this reactivation often represents an amplification of the Hb F synthesis in vivo.

Adult↗
PubMed1980

Diabetic control in 102 insulin-treated out-patients.

Haemoglobin AIc concentrations were measured in 102 insulin-treated diabetic outpatients. Only 19% had Hb AIc levels below three standard deviations above the normal mean value (5.23 +/- 0.05%). There were no correlations between Hb AIc levels, random C-peptide immunoreactivity or age. A significant correlation (r = 0.49; p < 0.001) was, however, observed between HbAIc and random plasma glucose levels. The mean random plasma glucose value was normal (89 +/- 18 mg/100 ml; 5 +/- 1 mmol/l) in the patients on insulin three times a day who had received short acting insulin 160 +/- 6 min before the sampling. --A significant inverse correlation was found (r = -0.26; p < 0.01) between the number of daily insulin injections and the HbAIc concentration. --These results suggest that the use of multiple daily insulin injections improves diabetic control. It should however be emphasised that the patients receiving multiple insulin injections were younger than those on the single injection regime and had lower plasma insulin antibody titres, different social and psychological status and a shorter duration of the disease.

Adult↗
PubMed1980

International transoceanic kidney sharing.

The shortage of cadaver kidneys for transplantation persists in most regions of the United States. Because so many patients have preformed antibodies against prospective donors, identification of appropriate donor-recipient pairs is proving difficult in spite of computerized interregional sharing. To avoid wasting valuable human organs, we have shared 11 kidneys between Italy, the Soviet Union, West Germany and the USA, 10 of which resulted in successful transplants. Such sharing guarantees better utilization of kidneys bilaterally and aids in transplanting cytotoxic patients by increasing the total number of kidneys available.

Cadaver↗
PubMed1980

The human alpha-globin gene. The protein products of the duplicated genes are identical.

In order to determine whether any heterogeneity exists in the human alpha-globin chain, i.e. whether the products of the duplicated genes are identical, we have determined the total sequence of 14 alpha-globin chains: seven of these were abnormal, while six were normal chains from the same individuals, with one additional sample which consisted of the alpha chains from a normal control. In the individuals heterozygous for an alpha-chain abnormality, the product of a single alpha-gene could be isolated from that of the three others using the differing physicochemical properties of the mutant haemoglobins. In the special situation of a double heterozygosity for an alpha-chain abnormality, the products of the two mutated genes were separated from each other and from the mixture of the products of the two normal genes. They were then investigated independently, this approach increased the precision of our work. During the course of the present investigation, sequence determinations were mainly performed on large fragments of the chains, which were purified exclusively by gel chromatography. In this way mixtures of products of several genes could be studied, thereby overcoming the risk of losing peptides differing slightly in sequence. Such loss may often occur when using ion-exchange procedures to purify small peptides. Our results show the absence of any heterogeneity at the level of the gene products of the duplicated alpha loci. Thus the human alpha-globin chain has to be considered as homogeneous.

Amino Acid Sequence↗
PubMed1980

Globin-chain affinity chromatography on Sepharose-haptoglobin: a new method of study of hemoglobin synthesis in reticulocytes, in bone marrow and in colonies of erythroid precursors.

In the present work we have developed an affinity chromatography system, using haptoglobin bound covalently to Sepharose 4B, to purify hemoglobin from soluble non-heme proteins. Sepharose-haptoglobin specifically binds hemoglobin. It exhibits the same characteristics in its interactions with hemoglobin and alpha or beta hemoglobin chains as does haptoglobin in solution. Globin chains can be eluted from the Sepharose-haptoglobin after removal of the heme. This method has allowed accurate measurements of globin-chain synthesis in blood and bone marrow samples and in culture of early erythroid precursors.

Adult↗
PubMed1980

Elevated Hb F associated with beta-thalassaemia trait: haemoglobin synthesis in reticulocytes and in blood BFU-E.

The red cells of a patient heterozygous for beta-thalassaemia contained 19% fetal Hb. Study of his family suggested that the proband had inherited the Swiss type of hereditary persistence of fetal Hb (HPFH) from his mother who is not thalassaemic and possessed 1.37% of Hb and 11% F-cells. Studies of globin synthesis showed a similar imbalance in the heterocellular HPFH-beta-thalassaemia compound heterozygotes and in the heterozygous beta-thalassaemic members of the family. Age stratification of the red cells showed a slight enrichment in Hb F and a decreased Hb A2 level in the older cell populations. Hb F production in the BFU-E colonies of the proband was higher than that found in vivo and in other beta-thalassaemic heterozygotes in culture. Study of single erythroid burst colonies showed a marked heterogeneity in Hb F synthesis from one colony to another, while the pool of free alpha-chains remained of similar magnitude. It is suggested that in the proband, the HPFH gene, which is in trans with respect to the beta-thal-gene, increases the size of the F-cell population and its activity is carried on at the expense of the normal beta A gene.

Cells, Cultured↗
PubMed1980

A gamma and G gamma globin chain synthesis in BFU-E colonies from adult, newborn, and fetal subjects and from thalassemic patients.

The G gamma and A gamma content of Hb F produced in cultures of BFU-Es from the blood of normal fetuses, neonates, and adults was determined. The results show that erythroid progenitors produce A gamma and G gamma chains in a ratio characteristic of their ontogenic stage. The analysis of the G gamma/A gamma ratio in culture of BRU-Es from thalassemic patients showed a marked heterogeneity, resembling that observed in freshly drawn cells. These results afford evidence that the type of gamma chain produced is programmed at the level of early erythroid progenitors.

Adult↗
PubMed1980

Prenatal diagnosis of hemoglobinopathies: comparison of the results obtained by isoelectric focusing of hemoglobins and by chromatography of radioactive globin chains.

Isoelectric focusing (IEF) of hemoglobin was compared to the classical chromatography of labeled globin chains for 22 antenatal diagnoses of hemoglobinopathies: 11 for beta thalassemia, and 11 for sickle cell disease. In all cases, the two methods gave identical results. The diagnosis was confirmed after birth or abortion. Three fetuses homozygous for beta thalassemia and one homozygous for sickle cell disease exhibited no Hb A by IEF, in contrast to normal fetuses or those heterozygous for one of the two hemoglobinopathies. In addition, blood samples obtained in other centers after abortion of 22 fetuses homozygous for beta + or beta 0 thalassemia exhibited no Hb A when analyzed by IEF. When Hb A was present, the respective proportions of Hb A and acetylated Hb F were determined by densitometry of the IEF gel. The Hb A/acetylated Hb F ratio obtained by IEF correlated well with the beta A/gamma ratio of globin chain synthesis, IEF requires 0.1 mg of unlabeled hemoglobin. It is performed in 90 min and several samples can be analyzed simultaneously. If present, maternal contamination of fetal blood must be eliminated by selective lysis of maternal (RBC) using the Orskov reaction. Improvements in this method to obtain suitable samples for IEF analysis are described.

Anemia, Sickle Cell↗
PubMed1980

[Evaluation of three commercial kits for the estimation of total glycolysed hemoglobin: Hb Al (author's transl)].

It has been demonstrated by numerous workers that variations in levels of glycolysed hemoglobins Hb Al (Alb, Alb, Alc) are an excellent means of control of the quality of diabetes control. The estimation of the main glycolysed hemoglobin (Hb Alc) is very difficult, and various chromatographic methods have been developed to permit rapid estimation of all these glycolysed hemoglobins. Our work consisted of testing the three microcolumn kits on the french market: Isolab, Helena and Biorad. The great thermo-dependency of the first two kits did not permit us to obtain results in correlation with those of our reference technic derived from Trivelli's method. On the other hand, the levels of Hb Al obtained with the Biorad kit were perfectly correlated with the levels of Hb Alc. The average normal of Hb Al was 6,45 +/- 0,66 p. cent, CV 10,2 p. cent; the average value of Hblc was 5,4 +/- 0,4 p. cent. CV 7,4 p. cent. The average levels of Hb A obtained in diabetic subjects was 12 p. cent, the levels of Hblc being 10 p. cent. Certain restrictions in the use of these microcolumns were demonstrated: presence of Hb F or abnormal Hb, hyperlipemia and presence of chylomicrons.

Adolescent↗
PubMed1980

[Clinical and biological studies of an hybrid S/Stanleyville II hemoglobin (alpha 2 78 Asn replaced by Lys beta 2 6 Glu replaced by Val) (author's transl)].

A report of a doubly heterozygous case for both haemoglobins: Hb Stanleyville II (alpha 78 replaced by Lys) and Hb S (beta 6 Glu replaced by Val) with Hb hybrid S/St II. A 29-year-old woman from Zaïre was found to have four haemoglobins: Hb A, Hb Stanleyville II, Hb S and Hb hybrid S/St II. The clinical and hematological effects of this combination were similar to those of heterozygous sickle cell anaemia. Substitution of Lysin for Asparagin at residue alpha 78 reduced the tendency to polymerization and increased mechanical stability. These findings demonstrated involvement of this site in intermolecular interactions and explained the moderate severity of the sickle cell anaemia syndrome.

Adult↗
PubMed1980

Effects of ethanol on amino acid uptake by rat liver cells.

The effects of ethanol on amino acid uptake were investigated in primary cultures of parenchymal cells isolated from adult rat liver. Sodium-dependent and energy-requiring amino acid transport was studied by measuring the uptake of the nonmetabolizable acid, alpha-amino isobutyric acid (AIB). Ethanol (80 to 100 mM) inhibits both basal and insulin-stimulated AIB uptake, measured after 21 hours of exposure to ethanol. Both the initial rate and cumulative uptake of AIB are inhibited. Although inhibition of basal uptake may involve an effect on more than one system for amino acid transport, the inhibition of insulin-stimulated AIB uptake suggests a major effect on the "A" system. The inhibition is dependent on the concentration of ethanol and results in an increase in Km, but no change in Vmax. Blocking the metabolism of ethanol by pyrazole does not prevent the inhibition of AIB uptake. Under these conditions, the presence of ethanol, rather than its metabolism, appears to inhibit amino acid transport. Inhibition of amino acid transport by ethanol may play a role in the ethanol-induced interference with hepatic gluconeogenesis and protein synthesis.

Adenosine Triphosphate↗
PubMed1980

Cord blood screening for hemoglobin abnormalities by thin layer isoelectric focusing.

Hemoglobin variants can be successfully identified in cord blood samples. The methods most commonly used include cellulose acetate (CAC) and citrate agar (CAG) electrophoresis. Recently thin layer isoelectric focusing (TLIF) has been shown to be an excellent method for identifying hemoglobin variants. To determine the applicability of TLIF for cord blood screening, we compared the results of 835 samples obtained by TLIF with that obtained by CAC, CAG, and the combination of both CAC and CAG. In 100 of these samples we detected an abnormal hemoglobin pattern using TLIF. In contrast, we detected only 80 abnormal samples by CAC, 70 by CAG, and 80 by using the combination of CAC and CAG. Due to the increased resolution provided by TLIF, we correctly diagnosed two sickle cell trait samples by TLIF that were incorrectly suspected to be homozygous for sickle cell disease by CAC and CAG. We identified 41 samples containing Bart's hemoglobin by TLIF in contrast to only 21 using CAC and 14 using CAG. The time and cost of TLIF was comparable to that using the combination of both methods. We, therefore, conclude that TLIF is the method of choice for cord blood screening.

Anemia, Sickle Cell↗