Isolation of omnipotent suppressors in an [eta+] yeast strain

Omnipotent suppressors decrease translational fidelity and cause misreading of nonsense codons. In the presence of the non-Mendelian factor [eta+], some alleles of previously isolated omnipotent suppressors are lethal. Thus the current search was conducted in an [eta+] strain in an effort to identify new suppressor loci. A new omnipotent suppressor, SUP39, and alleles of sup35, sup45, SUP44 and SUP46 were identified. Efficiencies of the dominant suppressors were dramatically reduced in strains that were cured of non-Mendelian factors by growth on guanidine hydrochloride. Wild-type alleles of SUP44 and SUP46 were cloned and these clones were used to facilitate the genetic analyses. SUP44 was shown to be on chromosome VII linked to cyh2, and SUP46 was clearly identified as distinct from the linked sup45.

Motor slowing in asymptomatic HIV infection

To examine neuropsychological deficits associated with the human immunodeficiency virus (HIV), 25 asymptomatic homosexual men and sexual partners of intravenous drug users and 25 seronegative homosexual men and nonhigh-risk heterosexuals were assessed on measures of fine motor control, visual scanning, attention, depression, and global psychological functioning. Analysis suggested that HIV infection is associated with reduced fine motor control. Seropositivity is associated with elevated depression and global psychological maladjustment. When depression and global adjustment were analyzed as covariates, motor slowing was evident in the seropositive group. These findings suggest an association between motor slowing and HIV infection in asymptomatic subjects and point to the necessity of measuring affect at least as a control variable. Further study is needed to determine whether the fine motor deficit evident in this sample is limited to distinct subgrouping of the over-all sample.

Neonatal seizures: the Dublin Collaborative Study

Asphyxial seizures occurred in 89 of 101,829 infants born alive at term (0.87/1000) in three large maternity hospitals from January 1980 to December 1984. These seizures were significantly associated with antenatal complications, primiparity, and prolonged pregnancy. Meconium staining of the amniotic fluid was also associated with asphyxial seizures, but there were high false positive (11%) and false negative (50%) rates. Fifteen of the infants who had seizures died (18%) and 21 (25%) were handicapped at 1 year. Outcome was most successfully predicted by the way the infant was feeding at 1-2 weeks. All infants taking more than half their estimated requirements by mouth at 1 week were normal, and those still being fed by tube at 2 weeks were handicapped.

Appearance and characterization of lipoprotein X during continuous intralipid infusions in the neonate

The development of hyperphospholipidemia and hypercholesterolemia was studied in infants that required total parenteral nutrition and given a continuous infusion of Intralipid, (1-4 g/kg body wt per 24 h. Detailed studies were carried out on infusion periods lasting 1-10 d. After 24 h there was a marked increase in plasma free cholesterol (68%) and phospholipid (77%) concentrations. Based on the amount of cholesterol in Intralipid, and the rate of infusion, it was estimated that at least 50% of the plasma cholesterol increment during 64-h infusions was derived from endogenous sources. By contrast, the hyperphospholipidemia could be attributed to the Intralipid as the rise in plasma was calculated to be equivalent to only 16% of the exogenous phospholipid infused. Approximately 10% of the phospholipid in Intralipid was in a triglyceride-free mesophase form with a free cholesterol:phospholipid molar ratio of 0.063. There were no systematic changes in plasma concentrations of cholesterol ester or triglyceride during Intralipid infusions. The increase in free cholesterol and phospholipid was localized in the low density lipoproteins (d = 1.006-1.063 g/ml). The presence of lipoprotein X (Lp-X) in the low density lipoprotein fraction was demonstrated by electrophoresis in agar and by isolation and chemical characterization with hydroxylapatite chromatography. Isoelectric focusing of urea-soluble protein of Lp-X revealed that albumin and apolipoproteins CII and CIII were major components, whereas apolipoprotein E and AI were minor constituents. The abnormal lipoprotein was apparent by 16 h during 64 h of infusion. After 6 d of continuous infusions the free cholesterol in Lp-X was 30+/-10 mg/dl (mean+/-SD), which represents a total Lp-X mass of 90 mg/dl. After cessation of the infusion, Lp-X, as monitored by electrophoresis in agar, disappeared within 72-96 h. Thus, during infusion of Intralipid in infants at rates commonly employed, the capacity of the clearance mechanisms for phospholipid are exceeded, which causes the accumulation of phospholipid and free cholesterol in the form of Lp-X particles. It is suggested that mesophase phospholipids in Intralipid may play a significant role in this process.

Further isolations of reovirus type 3 from cases of Burkitt's lymphoma

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