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Haemoglobinopathies are a group of inherited disorders caused by structural variations of the haemoglobin molecule. We report the case of a 5-year-old girl suffering from chronic haemolytic anaemia. A diagnosis of compound heterozygous sickle cell disease (SCD) and β0-thalassaemia was established using haemoglobin sub-fractionation studies and parental screening. The latter revealed the father and mother to have heterozygous SCD and heterozygous β-thalassaemia, respectively. Evaluation of children with a haemolytic anaemia requires a thorough history and physical examination, appropriate laboratory testing and careful interpretation of the results. [ABSTRACT FROM AUTHOR]

We report the use of alpha 2b-interferon in 15 children with symptomatic, chronic idiopathic thrombocytopenic purpura, who did not respond to standard therapy. The platelet count increased in nine children during therapy. In six children the increase lasted less than 6 weeks. An increased platelet count was seen when a higher dose was used in two of four initial nonresponders. One responder who relapsed had an identical response when retreated with the same dose. No significant side effects were documented. Further studies are required to establish the optimal dose and administration schedule of alpha 2b-interferon for use in children with chronic idiopathic thrombocytopenic purpura.

Tests were carried out on 198 patients with inherited coagulation disorders attending haemophilia clinics of Johannesburg and Baragwanath Hospitals for the prevalence of antibodies to the human immunodeficiency virus (HIV). This cohort of patients has been treated with locally produced (South African) blood products from volunteer donors, except for a 15-month period in 1982-1984 when, owing to a shortage of locally produced material, an imported large donor-pool US factor VIII concentrate was used. Not all patients received this material. Of the haemophilia A patients who received the imported factor VIII concentrate, 85% were seropositive, while only 3% of the patients who received locally produced small donor-pool products were seropositive. No factor VIII-deficient patients have seroconverted while using small donor-pool products, since the introduction of routine screening of blood donations and strict exclusion criteria of donors. However, despite testing of blood products, 3 patients receiving locally produced factor IX concentrate (4,000 donors) seroconverted in 1988, having previously been HIV-negative. Factors influencing the choice of blood products to be used, especially in South Africa, are discussed.

To test our hypothesis that specific interactions of ACTH peptides with model lipid membranes reflect the biological importance of similar interactions on target cells, we investigated the liposome-mediated labeling of ACTH fragments with the extremely hydrophobic photolabel, 3-trifluoromethyl-3-(m-[125I]iodophenyl)diazirine. Correlations were found between the labeling rates and the agonistic and antagonistic potencies of the peptides for in vitro steroidogenesis and inhibition of a synaptosomal protein kinase. A model for the cross-reactivity between ACTH and opioid peptides is discussed.

The purpose of this experimental investigation was to provide a purified plasma membrane fraction containing a highly hormone-responsive adenylate cyclase system. Bovine adrenal cortex was homogenised and a washed pellet (450 000 X g - min) was fractionated by zonal centrifugation in a sucrose and dextran gradient. Adenylate cyclase activity was purified up to 60-fold to a specific activity of 55, 340 and 210 pmol of adenosine 3':5'-monophosphate (cyclic AMP) produced/minute per mg of protein at 38 degrees C for the basal, adrenocorticotrophin and fluoride-activated states, respectively. The time course of the adenylate cyclase activity is linear. The concentration necessary for half-maximal stimulation by adrenocorticotrophin-(1-24)-tetracosipeptide is 0.5 muM. The high hormone-responsiveness of the membrane preparation allows one to demonstrate activation of adenylate cyclase by very weakly agonistic adrenocorticotrophin fragments. The F- activated state can be detergent-dispersed by Lubrol and shows a Km (ATP) different from that of either the basal or adrenocorticotrophin-stimulated state. Other marked enzymes such as 5'-nucleotidase, glucose-6-phosphatase and cytochrome oxidase were followed during purification. The plasma membrane fraction shows rather homogeneous, relatively large vesicles (mean diameter 0.5 mum). It contains high-affinity binding sites for angiotensin II (about 2 pmol per mg protein) with an apparent association constant of 2 X 10(7) (1/mol) at 12 degrees C. The yield, 20 mg of membrane protein per preparation, may make it a tool in either affinity-labelling studies with the peptide hormones mentioned or the starting point for solubilisation and purification of adenylate cyclase.

The discovery of regulatory peptides common to the nervous and the endocrine systems (brain, gut, and skin) has brought about a revolution in our concepts of endocrinology and neurology. We are beginning to understand some of the complex interrelationships between soma and psyche that might, someday, be important for an integrated treatment of diseases. Examples of the actions of certain peptides in the periphery and in the central nervous system are given, and their biosynthesis and molecular anatomy as carriers for information are discussed.

Chicken egg-white lysozyme forms a yellow complex with N-methylnicotinamide chloride. Titration studies utilizing the appearance of the yellow color as a measure of complex formation indicate that the weak complex (association constant k = 3.2 liter mole(-1)) involves a single class of binding sites on the lysozyme molecule. By analogy with similar titration studies on model compounds containing the indole moiety, the site for N-methylnicotinamide binding is probably the indole ring of a single, solvent-available tryptophan residue. The yellow color itself apparently arises from a charge transfer transition, with the indole ring system serving as the donor and N-methylnicotinamide as the acceptor. Complete resolution of the charge transfer spectrum of the lysozyme-N-methylnicotinamide complex was not achieved due to the very high absorbance of the protein near the short-wavelength absorption edge of the band. However, it is possible to consider the spectrum as the sum of two Gaussian bands whose positions and relative intensities agree remarkably well with the positions and relative intensities obtained by Gaussian fitting of the charge transfer spectra of several model complexes between substituted indoles and N-methylnicotinamide. The geometry for such complex formation requires that the ring faces of both donor and acceptor be more or less completely available for complexation. The possible use of N-methylnicotinamide as a molecular probe for tryptophan residues having at least one indole ring face freely available to the solvent is discussed.