Role of tissue hypoxia as the mechanism of lactic acidosis during E. coli endotoxemia.

We compared the hemodynamic and metabolic alterations produced in rabbits by similar decreases in cardiac output created by inflating a balloon placed in the right ventricle (n = 6) with those produced by an intravenous bolus of Escherichia coli lipopolysaccharide (LPS; SEP group; n = 6). We measured O2 consumption (VO2), O2 transport (TO2), and O2 extraction ratio (ERO2) for the whole animal and also for the left hindlimb. Both groups experienced similar decreases in cardiac output, systemic TO2, and VO2 and similar increases in ERO2. For the hindlimb, TO2 was similar, but VO2 and ERO2 were lower for the SEP group 30 min after LPS administration (P less than 0.05); however, this difference disappeared during the remainder of the experiment. Arterial lactate concentration was greater (P less than 0.05) for the SEP group. There were no differences in skeletal muscle PO2, measured with a multiwire surface electrode, or in cardiac and skeletal muscle concentrations of high-energy phosphates. We hypothesize that a direct effect of LPS on cellular metabolism may have resulted in greater arterial lactate concentration for the SEP group.     

Enhancement of specific nitrogenase activity inAzospirillum brasilense andKlebsiella pneumoniae,inhibition inRhizobium japonicum under air by phenol

Specific nitrogenase activity inAzospirillum brasilense ATCC 29145 in surface cultures under air is enhanced from about 50 nmol C₂H₄·mg protein^-1·h^-1 to 400 nmol C₂H₄ by the addition of 1 mM phenol. 0.5 and 2 mM phenol added increase the rate 5-fold and 4-fold. This enhancement effect is observed only between 2 and 3 days after inoculation, with only a small reduction of the growth of the cells by the phenol added. In surface cultures under 1% O₂, nitrogenase activity is slightly reduced by the addition of 1–0.01 mM phenol. Utilization of succinate is enhanced during the period of maximum enhancement of nitrogenase activity by 60% by addition of 1 mM phenol. The cells did not produce¹⁴CO₂ from [U-¹⁴C] phenol, neither in surface cultures nor in liquid cultures and less than 0.1% of the phenol was incorporated into the cells. A smaller but significant enhancement of nitrogenase activity by about 100% in surface cultures under air was found withKlebsiella pneumoniae K 11 after addition of 1 mM phenol. However, inRhizobium japonicum 61-A-101 all phenol concentrations above 0.01 mM reduced nitrogenase activity. With 1 mM phenol added activity was reduced to less than 10% with no effect on the growth in the same cultivation system. With thisRhizobium japonicum strain significant quantities of phenol (25 mol in 24 h by 2·10¹² cells) were metabolized to¹⁴CO₂, with phenol as sole carbon source. WithAzospirillum brasilense in liquid culture under 1% and 2% O₂ in the gas phase, no enhancement of nitrogenase activity by phenol was noticed.     

Hypertrophic cardiomyopathy associated with left ventricular aneurysm and normal coronary arteries: Case study indicating genetic tendencies of cardiomyopathy

A 50-year-old man presented with hypertrophic obstructive cardiomyopathy (HOC) associated with a left ventricular aneurysm and normal coronary arteries. His history revealed no evidence of myocardial infarction or atypical angina. Physical examination disclosed HOC but did not suggest the presence of an aneurysm. Although the patient was treated medically, heart failure ensued, and he died suddenly while working his farm. Subsequent investigation of the patient's family revealed that three of his five children were also affected by cardiomyopathy, which was especially pronounced in the eldest, a 22-year-old man. The possible hemodynamic relationship between HOC and left ventricular aneurysm is discussed, along with probable indications. The role of left ventricular aneurysm is also presented in relation to the natural history of the disease.     

Particle selection in the nauplius of Calanus pacificus

Food selection by the nauplius of Calanus pacificus is definedas the ability to ingest certain kinds of particles in behavioralpreference to others that occur simultaneously in the same environment.Using mixtures of planktonic algae and plastic beads of differentor similar sizes, the nauplii strongly selected the algal cells,consuming them almost exclusively, and at similar rates to thecontrols with only algae. In some cases, however, ingestionrates on the algae were lower than the in the controls, mainlywhen the mixture was composed of algal cells and plastic beadsof smaller sizes able to be captured by the nauplii. Selectionof algal particles was also observed when pollen grains or detrituswere used instead of the plastic beads. Selection behavior alsooccurred when mixtures of two algae of different sizes wereoffered to the nauplii, and it was dependent on the proportionand concentration of both kinds of algae in the mixture. Thepossible effect of particle production on the observed selectivepatterns is discussed.     

Distribution of RNA polymerase on Drosophila polytene chromosomes as studied by indirect immunofluorescence

Using indirect immunofluorescence visualization techniques we investigated the in situ distribution of RNA polymerase B on Drosophila melanogaster polytene chromosomes. The enzyme was found at many sites distributed throughout the genome in a pattern clearly distinct from that observed for histone H1, but it was especially concentrated in puffs induced by heat shock.     

A gel-forming (1→3)-β-D-glucan isolated from cyttaria harioti fischer

An alkali-soluble glucan, [α]_D + 11° (M potassium hydroxide) having a degree of polymerization of 220, has been isolated from the fruit bodies of the tree fungus Cyttaria harioti Fischer. Periodate oxidation and methylation analysis show that it consists of a highly branched β-D-(1→3)-linked backbone. Hydrolysis of the methylated polysaccharide yielded 2,3,4,6-tetra-O-methyl- (24.5 mol%), 2,4,6-tri-O-methyl-(39.4 mol%), 2,3,4-tri-O-methyl- (8.6 mol%), and 2,4-di-O-methyl-D-glucose (27.5 mol%). Periodate-oxidation results substantiate the methylation studies. The general structural features of the glucan are discussed.