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Biomedical subjects

H Lehmann

Publications and source records attributed to H Lehmann.

At least 109 records · Page 6Linked to original sources
PubMed1985

Homozygosity for the delta-chain variant haemoglobin A2' (HbB2) (delta 16 Gly----Arg).

A healthy 20-year-old woman, belonging to the Kgalagadi tribe of Botswana, has been found to possess a variant Haemoglobin A2 as her only minor haemoglobin component. Fingerprinting and amino-acid analysis have shown that it is Haemoglobin A2' (delta 16 Gly----Arg). The one parent available for study is heterozygous for the Hb delta A2' allele and the variant haemoglobin accounts for 3% of the total haemoglobin in the proband. It is reasoned that the proband is, therefore, homozygous for the Hb delta A2' allele. No haematological abnormalities were evident.

Adult↗
PubMed1984

Haemoglobin Warwickshire (beta 5 [A2] Pro----Arg). A possible 'fine tuning' of 2,3-DPG affinity by beta 5 Pro.

The blood of a 67-year-old Scotsman who was admitted to hospital with an abdominal carcinoma showed an abnormal red cell lysis in the oxidase channel of the Technicon H6000 analyser. This is seen regularly with Hb C and sometimes with Hb S and on further investigation a new haemoglobin variant--Hb Warwickshire--was found. When the family was examined, other examples were revealed. The haematological parameters were normal. Hb Warwickshire is mildly unstable and whilst in the absence of phosphates its oxygen dissociation does not differ from that of Hb A, a small fall of oxygen affinity is noted when phosphates are present.

2,3-Diphosphoglycerate↗
PubMed1984

The myoglobin of primates: the Night Monkey, Aotes trivirgatus (Cebidae, Platyrrhini, Anthropoidea).

The amino acid sequence of the myoglobin of the South American Night Monkey, Aotes trivirgatus, is identical to that of the marmoset (Callithrix jacchus [1]) except for residue 21 which is isoleucine in the marmoset, like in all other anthropoids, but valine in Aotes. Analysis of a possible pathway of the evolution of Aotes myoglobin using 18 known primate myoglobin sequences [2-5] supports the classification of the Night Monkey within Anthropoidea and Platyrrhini but it indicates that this species might be more closely related to the marmoset (family Callitrichidae) than to the family Cebidae as a member of which it is commonly classified.

Amino Acid Sequence↗
PubMed1984

Serum antibody response and germinal centre reaction in the upper respiratory tract after antigen challenge in mice.

In order to establish an experimental model for the study of immunological reactions to exogenic immunogens in the upper and lower respiratory system NMRI mice were subjected to inhalation of the mitogenic and inflammatory response inducing lectin concanavalin A (Con A) and bovine serum albumin (BSA). Immunological reactions were induced in the upper respiratory tract and in the lungs. Serologically, the course of the antibody titre was measured by radio-immunoassay over several weeks. Germinal centre reactions in the nose and paranasal sinus equivalents were the morphological correlate. The lungs showed an increase in the number of macrophages and a thickening of the alveolocapillary membrane, but no germinal centre reactions were observed. These morphological and serological results may indicate a priming of the immune response in the upper respiratory tract leading to a subsequent production of antibodies in the lung.

Aerosols↗
PubMed1984

Sickle cell anemia 35 years ago: reminiscence of early African studies.

The author was a biochemist who, because he had experience in plasma iron estimations, became involved in the investigation of a hypochromic anemia in India during World War II. This led to another such study in Uganda after the war. There, an investigation of the incidence of sickling led to the discovery of overall differences between Hamitic-speaking tribes and the Bantu and Nilotes. A few exceptions could later be explained on the basis of the effect of malaria on sickling incidence. A mapping of the world distribution of sickle-cell and other hemoglobins followed, as well as a search for factors which cause the severity of sickle-cell anemia to vary. A most important lowering influence on this severity seems to be that of alpha-thalassemia. It is suggested that the high incidence of alpha-thalassemia type 2 (alpha/alpha alpha) in malarial regions is not related to malaria itself but to the beta-chain abnormalities which protect against malaria and therefore are frequent in the same populations. Alpha thalassemia in turn has a selective value because it lowers the pathological effect of sickle-cell anemia, as well as the consequences of Hemoglobin E and beta-thalassemia.

Africa↗
PubMed1984

Ultrastructure of Anaulus creticus Drebes & Schulz with special reference to its reduced ocelli.

The ultrastructure of the vegetative cell of the centric diatom Anaulus creticus Drebes & Schulz is described. Exhibiting the organic wall component (diatotepum) separated from the siliceous parts of the cell wall this species belongs to the diatom group with so-called split-walls [17]. A most interesting feature of the Anaulus cell is the horn region and its internal structure. As there is no silicified sieve-plate at the horn top but just a big hole sealed only by a thin diatotepum with a hexagonal meshwork, this wall structure is termed a "reduced ocellus". The inner part of the horn region is largely occupied by a conspicuous protoplasmic plug of proteinaceous nature. The possible function of this peculiar structure is discussed as well as new ideas about the role of the labiate process are provided.

Eukaryota↗
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↗
PubMed1983

Haemoglobin LeporeBaltimore in a Spanish family.

Description of the clinical, haematological and biochemical aspects of a new family with heterozygous haemoglobin LeporeBaltimore. Of the 6 members affected. 4 were totally asymptomatic. All of them showed morphologic features of heterozygous beta-thalassaemia. The levels of haemoglobin Lepore ranged from 12.2 to 15% (mean value: 13.7 +/- 1.1%). The analysis of the primary structure of the haemoglobin shows that crossing over takes place between amino acid 50 of the delta-chain and amino acid 86 of the beta-chain. This is the third family, to our knowledge, with haemoglobin LeporeBaltimore so far described.

Adolescent↗