INTRACARDIAC TUMOURS – EXPERIENCE WITH 12 CASES

Twelve cases of intracardiac tumours operated during the period 1975 to 1994 are presented. There were 8 males and 4 females in the age range of 18 years to 64 years. Tumours were located in the left atrium in 10 patients and in the right atrium in 2 patients. Standard cardiopulmonary techniques were followed. The right atrial tumours were approached through a right atrial incision while the left atrial tumours were approached through a bi-atrial trans-septal approach. One patient underwent a perineal urethrolithotomy for an impacted urethral calculus at the same sitting. Eleven of the tumour masses excised were myxomas confirmed on histopathology. The last patient, operated for synovial sarcoma of the left knee 2 years before, presented with a metastatic tumour mass in the left atrium. No deaths occurred in the series.KEY WORDS: Heart neoplasms, Heart surgery, Myxomas     

Diet, plasma lipoproteins and experimental atherosclerosis in baboons (Papio sp.)

Diet-induced hyperlipidaemia in baboons is similar to that inhumans. As in humans, the ratio between low density lipoprotein(LDL) and high density lipoprotein (HDL) cholesterol is a majordeterminant of atherosclerosis. Baboons, like humans and othernon-human primates, vary in their lipaemic responses to dietarylipids. By selective breeding based on variability in plasmaand lipoprotein cholesterol response to diet, lines of baboonswith high and low responses of various lipoproteins have beendeveloped. Genetic analyses suggest that lipoprotein patternsin responses to dietary cholesterol and fat are heritable. Metabolicand molecular studies of high and low LDL and HDL cholesterolresponses to dietary lipids have suggested that different mechanismsregulate plasma LDL cholesterol on the chow and on the highcholesterol-high fat (HCHF) diet. On the chow diet, plasma LDLcholesterol levels are positively associated with cholesterolabsorption and negatively associated with hepatic LDL receptorlevels and, thus, cholesterol absorption and LDL receptors seemto regulate plasma LDL cholesterol levels. However, when theanimals consume a human-like fat- and cholesterol-enriched diet,plasma LDL cholesterol levels are not associated with eithercholesterol absorption or hepatic LDL receptor mRNA levels,but are negatively associated with plasma 27-hydroxycholesterolconcentrations, hepatic sterol 27-hydroxylase activity, andmRNA levels. Hepatic sterol 27-hydroxylase activity and mRNAlevels are induced by dietary cholesterol and fat in low respondingbaboons more than in high responding baboons. Thus, the abilityto induce sterol 27-hydroxylase determines the LDL cholesterolresponse in baboons. High HDL response baboons often have highlevels of HDL₁ in their plasma. Our studies suggest that theN-terminal fragment of apo C-I with 38 amino acids and a molecularweight of 4 kDa acts as a cholesteryl ester transfer inhibitorpeptide in high HDL₁ baboons. The inhibitor peptide associateswith apo A-1 in HDL to produce a modified apo A-1 protein witha molecular weight of 31 kDa. The inhibitor peptide is a geneproduct and the presence of this peptide produces an antiatherogenichigh HDL₁ phenotype.     

1140406603The immunoglobulin superfamily protein Izumo is required for sperm to fuse with eggs

Representing the 60 trillion cells that build a human body, a sperm and an egg meet, recognize each other, and fuse to form a new generation of life. The factors involved in this important membrane fusion event, fertilization, have been sought for a long time. Recently, CD9 on the egg membrane was found to be essential for fusion, but sperm-related fusion factors remain unknown. Here, by using a fusion-inhibiting monoclonal antibody and gene cloning, we identify a mouse sperm fusion related antigen and show that the antigen is a novel immunoglobulin superfamily protein. We have termed the gene Izumo and produced a gene-disrupted mouse line. Izumo -/- mice were healthy but males were sterile. They produced normal-looking sperm that bound to and penetrated the zona pellucida but were incapable of fusing with eggs. Human sperm also contain Izumo and addition of the antibody against human Izumo left the sperm unable to fuse with zona-free hamster eggs.     

24-Hour urinary glucose excretion in assessment of control in juvenile diabetes mellitus

24-Hour urinary glucose excretion was measured in 43 juvenile diabetics during treatment as outpatients. In 20 children studied twice over 1-3 months there was good correlation between glucose excretion on each occasion. Subdivision of the collections into the periods 08 therefore 00-20 therefore 00 and 20 therefore 00-08 therefore 00 hours gave slightly less consistent results with correlation coefficients of 0 therefore 83 and 0 therefore 80, respectively, between the results of the repeat tests. In 37 prepubertal children, 24-hour glucose concentration and height velocity over the previous year were compared, and a highly significant negative correlation found. 10 of the 12 children with glucose excretion greater than 40 g/d had height velocities more than 1 SD below the mean for age, while only 2 of the 25 subjects excreting less than 40 g/d had height velocities more than 1 SD below the mean. The results indicate that estimation of 24-hour urine glucose excretion can be a useful index for monitoring treatment and that subdivision of the total collection may be of value in selecting the most suitable insulin regimen for the patient.