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Biomedical subjects

P A Lorkin

Publications and source records attributed to P A Lorkin.

At least 19 recordsLinked to original sources
PubMed1985

Hemoglobin Hofu associated with beta 0-thalassemia.

A mild anemia (hemoglobin 9 g/dl) was found in a patient from Seville (Spain) with marked morphological abnormalities in the peripheral blood smear. The red cell osmotic fragility showed a mild resistance curve with a mean cell fragility (MCF) of 0.375% NaCl (normal = 0.450). Chemical Chemical and thermal instability test and search for inclusion bodies gave positive results. Hemoglobin electrophoresis at pH 8.9 revealed absence of Hb A, a major component of fast mobility (94%), and increased Hb F and Hb A2 levels (1.5% and 4.6%, respectively). The fast fraction, isolated and purified by means of cellulose acetate electrophoresis, precipitated in acid acetone and treated with urea 8 M and mercaptoethanol, revealed an anomalous beta chain. Trypsin-digested globin peptides were separated by high-voltage electrophoresis at pH 6.4 and ascendant chromatography. With differential staining, an extra peptide was detected in an unusual site, more anodic than alpha Tp4 but in lower position. Peptide map of the fast beta chain, stained with ninhydrin, and also for Tyr, confirmed the position of the new peptide and the absence of the usual beta Tp13. The new peptide, separated by high-voltage electrophoresis at pH 3.5, revealed absence of Val and the presence of an additional Glu residue, which should appear only in position beta 126. The diagnosis of Hb Hofu (alpha 2 beta 2 126 Val----Glu; H4) was reached, thus interpreting its increase and the absence of Hb A, as an association with beta o-thalassemia, producing a mild hemolytic anemia. Evidence was obtained that Hb Hofu is a mild unstable hemoglobin variant.

Adult↗
PubMed1983

Malignant hyperthermia in pigs: a search for abnormalities in Ca2+ binding proteins.

Malignant hyperthermia occurs in man and pigs as a hereditary disorder notably as a complication of halothane-induced anaesthesia. It involves an abnormality in the metabolism of Ca2+. A search was made for abnormalities of calcium-binding proteins. Troponin C from normal pig muscle was found to differ in 2 of 159 amino acids from rabbit Tn C and 3 from man. No differences between normal and abnormal pig muscle were found. Two-dimensional electrophoresis of red cell calmodulin from normal and abnormal pigs also failed to demonstrate a difference.

Amino Acid Sequence↗
PubMed1983

Investigation of malignant hyperthermia: analysis of skeletal muscle proteins from normal and halothane sensitive pigs by two dimensional gel electrophoresis.

Two dimensional gel analysis of skeletal muscles from normal pigs and from pigs which were homozygous for halothane sensitivity showed no obvious differences in the patterns of spots attributed to the major contractile proteins and glycolytic enzymes. In muscle from a sensitive pig which died of heat shock under anaesthesia there was a selective loss of glyceraldehyde-3-phosphate dehydrogenase and aldolase, presumably owing to proteolytic activity. The progressive loss of these enzymes under anaesthesia could contribute to the mechanism of heat production by diverting fructose 1,6 diphosphate into a futile cycle.

Actins↗
PubMed1976

The occurrence of Hb E Saskatoon in Scotland.

The finding of several examples of Hb E Saskatoon in the Orkney Islands, in Edinburgh and in individuals of Scottish descent in Canada but nowhere else, suggests that the original mutation occurred in Scotland, perhaps in the Orkneys.

Genetics, Population↗
PubMed1976

A drug-induced haemolytic anaemia due to Hb Torino (alpha43(CD1)Phe replaced by Val). second finding in an Italian family.

The unstable haemoglobin, Tb Torino (alpha43(CD1)Phe replaced by Val), has been found for the second time in a family from the Treviso region of Italy. The haemoglobin has a slightly lower oxygen affinity than normal. In both cases, the abnormal haemoglobin is associated with inclusion body anaemia but the course of the disorder in the present case is much less severe than that previously reported. The oxygen affinity of the haemolysate has been measured and been found lower than normal.

Adult↗
PubMed1975

Haemoglobin Rahere (beta Lys-Thr): A new high affinity haemoglobin associated with decreased 2, 3-diphosphoglycerate binding and relative polycythaemia.

A new haemoglobin with increased oxygen affinity, beta82 (EF6) lysine leads to threonine (Hb Rahere), was found during the investigation of a patient who was found to have a raised haemoglobin concentration after a routine blood count. The substitution affects one of the 2, 3-diphosphoglycerate binding sites, resulting in an increased affinity for oxygen, but both the haem-haem interaction and the alkaline Bohr effect are normal in the haemolysate. This variant had the same mobility as haemoglobin A on electrophoresis at alkaline pH but was detected by measuring the whole blood oxygen affinity; it could be separated from haemoglobin A, however, by electrophoresis in agar at acid pH. The raised haemoglobin concentration was mainly due to a reduction in plasma volume (a relative polycythaemia) and was associated with a persistently raised white blood count. This case emphasises the need to measure the oxygen affinity of haemoglobin in all patients with absolute or relative polycythaemia when some obvious cause is not evident.

Adult↗
PubMed1975

Haemoglobin G Norfolk: alpha 85 (F6) Asp leads to Asn.

The characterisation of haemoglobin G Norfolk (alpha2 85 Asp leads to Asn 2) is described. This variant has been identified in the heterozygous state in three apparently unrelated English families of which two are resident in England and the other in Canada.

Amino Acids↗
PubMed1975

Erythraemia due to haemoglobin San Diego.

A 63-year-old man with erythraemia was found to have a high affinity haemoglobin which was subsequently identified as Hb San Diego beta 109 (G11) Val leads to Met, recently described in a Filipino family (Nute et al, 1974). The oxygen affinity of the haemolysates was increased approximately two-fold at pH values between 6.04 and 7.90. The n value was nearly normal (2.5-2.9) in the upper range of saturation (70-95% oxygenation) but was somewhat diminished (1.9-2.1) below this range. In vitro biosynthesis of globin by reticulocytes showed that there was balanced synthesis of alpha and beta chains (alpha:beta ratio = 1).

California↗
PubMed1975

Homozygous haemoglobin D Punjab.

A homozygote for the gene controlling Hb D Punjab is described. The diagnosis is supported by the peptide analysis of the haemoglobin and the examination of both parents. There was no anaemia or reticulocytosis and there was balanced synthesis of both the alphaA- and betaD-globin chains in reticulocytes. However, the oxygen affinity of the haemolysate had a small but significantly higher oxygen affinity than normal. The only other abnormalities were a somewhat decreased osmotic fragility and a slight anisocytosis of the red cells.

Amino Acids↗
PubMed1975

Haemoglobin G-Szuhu, beta80 Asn-Lys, in the homozygous state in a patient with abetalipoproteinaemia.

An 11-year-old Jewish girl of Turkish extraction with abetalipoproteinaemia was found to be homozygous for haemoglobin Szuhu (beta80 Asn leads to Lys). Except for the abnormal haemoglobin, no other haematological or biochemical abnormalities were found in her consanguineous parents and one sister. In the propositus, erythrocyte morphology showed the acanthocytosis known to be in association with abetalipoproteinaemia. Increased autohaemolysis was also found, which reverted to normal after treatment with vitamin E. This case represents the first reported association of abetalipoproteinaemia with an abnormal haemoglobin, and the first homozygous Hb G-Szuhu.

Abetalipoproteinemia↗
PubMed1975

Futher investigations of the gamma-chaina in a ghanaian adult, homozygous for hereditary perisitence of fetal haemoglobin. Isolation of gamma CB-3 peptides and Ggamma:Agamma ratio determination in human Hb E.

The gamma-chain in a Ghanain homozygous for hereditary persistence of fetal haemoglobin was considered to be of the Ggamma type on the basis of the amino acid analysis of gammaTp XIV (gamma133-144) of the Hb F of this subject [1]. Recently, the sequence of residues gamma134-137 of the gamma-chain of this subject was determined and found to contain some alanine at position gamma136. It is therefore of the Ggamma + Agamma type. A rapid technique for the isolation of gammaCB-3 (gamma134-146) peptides in human fetal haemoglobin for Ggamma:Agamma ratio determination is described.

Adult↗
PubMed1974

Haemoglobin Belfast 15 (A12) tryptophan leading to arginine: a new unstable haemoglobin variant.

A new unstable haemoglobin, alpha(2)beta(2)15 Trp--> Arg (Hb Belfast), with increased oxygen affinity has been found during the routine investigation of a long-stay psychiatric patient. It seemed to cause little haematological disorder. The reticulocytes synthesized normal and abnormal beta-chains at the same rate but in the circulating blood Hb Belfast amounted to only 27.5% of the total haemoglobin.

Adult↗