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Biomedical subjects

H Kronenberg

Publications and source records attributed to H Kronenberg.

At least 145 records · Page 8Linked to original sources

Familial association of the lupus anticoagulant.

A lupus anticoagulant was detected in plasma from two pairs of siblings using the kaolin clotting time mixing test. Strong evidence for this inhibitor in one further sibling pair is presented. Although coagulation abnormalities are usually classified as either acquired or of genetic origin it is apparent that the lupus anticoagulant might often be an acquired coagulation defect requiring genetic predisposition.

Adolescent↗

Current trends in the management of myasthenia gravis: plasmapheresis and immunosuppressive therapy.

In recent years a considerable body of evidence has accumulated to demonstrate autoimmune mechanisms in myasthenia gravis. This evidence has important implications for the aetiology, diagnosis and management of the disease. The primary abnormality in myasthenia gravis is related to the presence of antibody which reacts with the acetylcholine receptor. Measurement of this IgG antibody in the serum has become the most reliable diagnostic adjunct to the edrophonium test, and in an individual patient, the level of the serum antibody relates closely to the clinical indices. In cases of myasthenia where control with anticholinesterase drugs is unsatisfactory, methods to lower the antiacetylcholine receptor antibody are indicated: these may include thymectomy, immunosuppressive therapy of plasmapheresis. Two patients with very severe disease are described in whom all types of therapy were used and in whom survival depended ultimately on the use of plasmapheresis. These patients illustrate the importance of receptor antibody in the clinical manifestations of myasthenia gravis and in its management.

Acetylcholine↗

Myocardial infarction, papillary muscle dysfunction and mitral valvular incompetence in systemic lupus erythaematosus.

A fatal case of systemic lupus erythaematosus complicated by myocardial infarction, papillary muscle dysfunction and mitral incompetence seven months before death is reported. Necropsy examination of the heart revealed that the infarct was due to multiple occlusive thrombi in epicardial branches of the corresponding coronary artery. No evidence of atherosclerosis or previous coronary arteritis was present.

Adult↗

Comparison of thromboplastins used for oral anticoagulant control.

Prothrombin ratio (PR) ranges of 1.5-2.5 based on clinical effect are used for oral anticoagulant control with most commercially available thromboplastins, whereas with Australasian Reference Thromboplastin (ART) 2.0-3.5 is recommended. Plasmas from patients taking oral anticoagulants were concurrently tested with various thromboplastins and interrelationships between these products were determined. Although PR's with ART appear higher, in fact therapy based on ART guidelines is considerably more conservative than that monitored with most commercial thromboplastins.

Administration, Oral↗

Some properties of the colony forming cell in adult acute leukaemia.

Variations in the concentration and physical characteristics of the bone marrow derived colony forming cell(CFC) have been studied in patients with acute leukaemia. Two-hundred-and-fifteen marrow samples from 83 patients provide the basis for this analysis. CFC concentration confirmed the clinical remission/relapse status and yielded some guidelines to prognosis in individual patients while the proportions of CFC in DNA synthesis also proved to be a most reliable indicator of disease status. In remission, CFC concentrations return to normal values whilst on presentation and in the relapse phase of acute leukaemia CFC numbers are reduced. Biophysical profiles of CFC established using albumin density gradient and velocity sedimentation studies also indicated the state of the leukaemic process in individual patients. By applying physical laws to the data obtained from such profiles, the mean volume, diameter, density and mass of CFC were calculated. CFC from leukaemic patients in relapse were up to twice the volume and mass although slightly less dense than CFC from normal patients. The reasons for these changes are explained and discussed.

Acute Disease↗

B cell leukaemia.

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Diagnosis, Differential↗

The colony forming cell in the myeloproliferative disorders and aplastic anaemia.

Bone marrow colony forming cell (CFC) concentration and the proportion of CFC in DNA synthesis were studied in myeloproliferative disorders and aplastic anaemia. Growth patterns of bone marrow cells in agar cultures were able to supplement traditional morphological and clinical criteria in the diagnosis of these haematological conditions. Bone marrow CFC concentration tended to be increased in chronic myeloid leukaemia (CML) and polycythaemia vera (PV), but decreased in myelofibrosis, erythroleukaemia, paroxysmal nocturnal haemoglobinuria (PNH) and the aplastic phase of aplastic anaemia. The proportion of CFC in DNA synthesis was decreased in CML, myelofibrosis and aplastic anaemia, but increased in blastic transformation, PV, PNH and during regeneration from aplastic anaemia. The proportion of CFC in DNA synthesis in bone marrow from patients with CML in blastic transformation was directly related to the percentage of myeloblasts in the bone marrow. CFC kinetics in blastic transformation have been demonstrated to be different from those in acute leukaemia.

Anemia, Aplastic↗

Immunoradiometric and electroimmuno assay of increased ferritin and apoferritin levels in serum.

Ferritin in serum from patients with increased serum ferritin levels has been studied both quantitatively and qualitatively. All techniques utilized in these studies are suitable to be used as routine screening tests for large numbers of patients. Electroimmuno assay (EIA) has been compared with the solid phase immunoradiometric (IRMA) assay as a technique to determine serum ferritin concentration (r = 0.99) and is suggested as a useful alternative when determining ferritin concentrations above 500 microgram/l. Iron stained EIA gels have been used to indicate the iron content of the ferritin molecule in sera. This simple screening test has demonstrated that apoferritin is found more often than iron-rich ferritin in the serum of patients with elevated serum ferritin levels. Immunoelectrophoresis precipitin bands suggest the heterogeneity of ferritin in serum from different patients.

Animals↗

Apparent antihaemophilic activity of basic amphoteric polyelectrolytes.

Amphoteric polyelectrolytes with alkaline isoelectric points (for example Ampholine 9-11) intended for use in isoelectric focussing were found to shorten the prolonged partial thrombosplastin clotting time with kaolin (PTTK) of plasma deficient in factor VIII. The response of this PTTK to Ampholine 9-11 was linear when plotted on double log paper with a slope slightly greater than that of factor VIII itself. Ampholine 9-11 at 2% concentration had factor VIII and factor IX activity equal to that of normal plasma as well as somewhat less activity as factor XI. It had no significant correcting effect on the clotting of plasmas deficient in factors V, VII, X, II OR XII. Ampholine 9-11 inhibited low concentrations of contact activators and its effect in correcting factor VIII deficient plasma was found to be related to the degree of contact activation.

Amino Acids↗

A sensitive test demonstrating lupus anticoagulant and its behavioural patterns.

The kaolin clotting time of platelet poor plasma was used as a sensitive test for detecting the lupus anticoagulant in mixtures of normal and patients' plasmas. Platelets were found to decrease the anticoagulant effect of a typical lupus inhibitor. Thus, high sensitivity in this test system was achieved by ensuring low platelet concentrations and omitting platelet lipid substitute. In 17 patients with disseminated lupus erythematosus (DLE), 12 had detectable inhibitor by this method, more than would be detected with routine coagulation tests. Mixing patterns were of four distinct types, representing three different modes of anticoagulant behaviour. The pattern (type 3) of plasma mixtures giving longer kaolin clotting times than the individual components could be reproduced in vitro by adding trace amounts of crude thrombin or platelet fragments to a more typical lupus anticoagulant-containing plasma; formation of such a mixing pattern by the plasma of a patient with DLE may therefore indicate activation of the coagulation pathway. Six patients with idopathic thrombocytopenic purpura (ITP) had no detectable inhibitor indicating that anti-platelet antibodies behave differently from the lupus anticoagulant.

Blood Cell Count↗

A new hybrid haemoglobin: haemoglobin Strumica/Beograd occurring in an individual with four haemoglobins.

An investigation of the cord blood from full term twin infants revealed an additional haemoglobin F component due to an abnormal alpha chain. The father of the twins, whose blood picture was normal, was shown to have normal alpha and beta polypeptide chains together with variant alpha and beta polypeptide chains. Electrophoresis showed that he had four major haemoglobin components. Separation of the haemoglobin fractions by column chromatography, globin preparation, chain separation, tryptic and chymotryptic digestion and peptide map preparation led to the identification of haemaglobin A, haemoglobin Strumica (alpha2 112His leads to Arg beta2), haemoglobin D Beograd (alpha2beta2 121 Glu leads to Val) and a hybrid haemoglobin Strumica D/Beograd (alpha2 112His leads to Argbeta2 121Glu leads to Val).

Alleles↗

The effect of cyclic AMP on human colony forming cell and colony stimulating factor production.

The effect of cyclic AMP (cAMP) and related nucleotides on human colony forming cells (CFC) and those cells producing colony stimulating factor (CSF) was studied in vitro. When added at physiological concentrations (10(-2) to 1 micron), exogenous cAMP stimulated maximum colony formation in cultures without feeder layers. Related nucleotides stimulated colony formation to a lesser extent and in decreasing order of free energy. All nucleotides inhibited colony formation in concentrations above 1 micron. A velocity sedimentation cell separation technique was used to obtain cell fractions rich in CFC but poor in CSF-producing cells. Such fractions did not respond to cAMP stimulation. These studies suggest that exogenous cAMP stimulates human bone marrow to form colonies in vitro by increasing the release and/or production of endogenous CSF.

Adenine↗

The isolation and identification of haemoglobin Lephore Boston (Washington) in an Australian family.

Haemoglobin Lepore is a haemoglobin variant associated with a thalassaemia-like disorder. It has been only rarely detected in Anglo-Saxons and its occurrrence in an Australian family of British and stock is reported for the first time. The appearances of the blood film resemble those seen in various hypochromic anaemias, inclusing thalassaemia traits, and on this account it is of clinical importance to recognize it in order to avoid unnecessary investigation and treatment. The chemical structure of nine examples of haemoglobin Lepore has been confirmed by peptide mapping and amino acid analysis, and the genetic mechanisms postulated for the production of haemoglobin Lepore are discussed.

Amino Acids↗