Biomedical subjects

M C Rozenberg

Publications and source records attributed to M C Rozenberg.

6 recordsLinked to original sources

PubMed1979

Family study on the kindred of an adenosine deaminase deficient child with severe combined immunodeficiency.

A study was performed on the family of a child with severe combined immunodeficiency and deficiency of the purine salvage pathway enzyme, adenosine deaminase (ADA). Sixteen relatives over three generations were studied. Erythrocyte ADA levels clearly indicated the heterozygous status of five members. A sixth member, whose erythrocyte ADA level of 48 nmol/hr/ml Hb was within two standard deviations (32) of the mean (76) was shown by ADA determination on platelets to be clearly heterozygous. Similarly, consideration of ADA data of either serum, platelets or lymphocytes only, would have failed to identify all heterozygotes. The survey shows that the identification of phenotype by the indirect means of enzyme level determination is enhanced by the simultaneous study of several tissues.

Adenosine Deaminase↗

PubMed1979

IgA deficiency, superior mediastinal tumour with unusual clinical manifestations.

The clinical course of a 17-year-old man with selective IgA deficiency and anaplastic carcinoma in the superior mediastinum is described. High swinging fevers, neutrophil leucocytosis reaching 60 x 10(9)/l, polyarthralgia and skin vasodilatation were unusual manifestations of the tumour. Marked tissue reactions in the neck and polyserositis occurred with a neutrophil granulocyte tissue reaction and progressed to fibrosis. Circulating immune complexes were present and IgE levels were grossly raised. It was not established whether the unusual clinical manifestations were due solely to the tumour or were an abnormal response of an IgA-deficient host. Review of the literature of malignancy in selective IgA deficiency casts doubt upon an increased incidence of neoplasm in this immune deficiency.

Adolescent↗

PubMed1979

The association of haemopoietic dysplasia (pre-leukaemia) and abnormal cell clone with connective tissue disease.

A 68-year-old man with haemotological features consistent with haemopoietic dysplasia (pre-leukaemia) and an abnormal cell clone in the marrow, 46, XY, -18, +t(13;18) (q11;123), developed acute connective tissue disease characterised by vasculitis, dermal changes, marked muscular weakness and serological features suggesting an auto-immune disturbance. Although four other cases of haemopoietic dysplasia ("pre-leukaemia") with unusual connective tissue disease had been reported since the recognition of haemopoietic dysplasia as a distinct entity, a definite association between these two disease states still awaits confirmation by further reports and investigations.

Aged↗

PubMed1979

Interpretation of serum and red cell folate results. A comparison of microbiological and radioisotopic methods.

Serum folate and red blood cell folate levels were measured in 167 patients using a microbiological method (Lactobacillus casei) and a commercial 125I radioassay kit. The results of the two methods were compared and related to the clinical findings to see which method more truly reflected the physiological folate status of the patient. There was a good linear correlation between the methods for both serum folate and red cell folate over the whole range encountered and the mean results obtained with each method were nearly identical. Both methods seemed to perform equally well in distinguishing low serum folate levels, but when the red cell folate results were compared to the clinical and other laboratory findings, the radioassay more closely related to the folate status of the patient. The study again emphasized the high number of low serum folate levels found in hospital patients and the importance of measuring the red cell folate.

Biological Assay↗

PubMed1979

In vitro platelet abnormality in adenosine deaminase deficiency and severe combined immunodeficiency.

The platelets of an infant with severe combined immune deficiency and adenosine deaminase deficiency showed markedly diminished responses to ADP-induced aggregation in vitro. This abnormality was corrected by the addition of purified adenosine deaminase in vitro. Exogenous adenosine added to platelet-rich plasma caused markedly prolonged inhibition of ADP-induced aggregation. This was shown by isotopic studies to be due to slow clearance of adenosine and hence persistence of this nucleoside. Direct assay for adenosine deaminiase in plasma and platelet lysates of the patient confirmed the very low activity of this enzyme. Raised cAMP levels were demonstrated in his platelets. The deranged adenosine metabolism and raised cAMP in the platelets of this child with severe combined immunodeficiency may explain the altered response to ADP. Despite the in vitro platelet aggregation abnormality, the patient had no clinical evidence of impaired hemostasis.

Adenosine Deaminase↗

PubMed1975

The effect of ADP, calcium and some inhibitors of platelet aggregation on protein phosphokinases from human blood platelets.

A protein phosphokinase (ATP: protein phosphotransferase EC 2.7.1.37) which is stimulated by 3',5'-cyclic adenosine monophosphate (cyclic AMP) has been partially purified from both the cytoplasmic and membrane fractions of human platelets. The kinetics of both enzymes preparations are similar in respect to cyclic AMP, ATP, ADP and AMP. 5-10-minus 7 M cyclic AMP stimulated both preparations by approximately 100%. Both ADP and AMP at a concentration of 5-10-minus 5 M inhibited protein phosphokinase activity of the soluble and membrane preparation by between 50% and 70%. The response of the two enzyme preparations to calcium differed. 10 mM Ca-2+ inhibited soluble protein phosphokinase activity approximately 80% both in the presence and absence of 5-10 minus 7 M cyclic AMP whereas the same concentrations of Ca-2+ inhibited the membrane-bound enzyme by approximately 60% in the presence of 5-10-minus 7 M cyclic AMP and 40% in the absence of cyclic AMP. This observation may be of importance in understanding the mechanism of platelet aggregation.

Adenosine↗