Increase in pulmonary capillary permeability in dogs exposed to 100% O2

Changes in pulmonary capillary filtration induced by hyperoxia were investigated in 15 dogs. After 12 h of normobaric hyperoxic exposure, animals were anesthetized and artificially ventilated with 100% O2. A pulmonary lymphatic vessel was cannulated, and lymph flow and protein content were measured together with pulmonary and systemic hemodynamics. An increase in pulmonary capillary filtration was found when compared with reference data (normoxic dogs in similar conditions) gathered from available literature: lymph flow increased from 21.8 +/- 13.4 to 125.2 +/- 131.6 microliter/min, and the lymph-to-plasma protein concentration ratio increased from 0.67 +/- 0.08 to 0.78 +/- 0.08. To characterize the mechanisms involved, left atrial pressure was increased in two stages (approximately 10 and approximately 25 mmHg). The results clearly indicated an increase in pulmonary capillary permeability as evidenced by a decrease of the minimal estimate of the protein reflection coefficient from 0.62 +/- 0.05 to 0.42 +/- 0.05.

DYSGENESIS-INDUCED INSTABILITY OF ROSY LOCUS TRANSFORMATION IN DROSOPHILA MELANOGASTER: ANALYSIS OF EXCISION EVENTS AND THE SELECTIVE RECOVERY OF CONTROL ELEMENT DELETIONS

ABSTRACT Utilizing the method of P-M hybrid dysgenesis-mediated gene transfer to insert rosy locus DNA into various chromosomal locations, we recovered a transformed strain that carries an ry + transposon inserted in or near the scalloped locus in polytene section 13F on the Χ chromosome. The resultant product, when stabilized, behaves as a homozygous and hemizygous viable and fertile extreme scalloped allele associated with wild-type expression of the rosy locus. We have labeled this allele, sdry+ +. This allele has been destabilized by subsequent P-M hybrid dysgenesis, and mutations were recovered that exhibit alterations in the rosy and/or scalloped phenotypes. Representative samples of all phenotypic classes have been characterized by Southern blot analyses of restricted DNA. The most common events are excisions of DNA wholly internal to the transposon and representing sections of rosy DNA. In addition to loss of rosy locus function, such excisions affect the scalloped locus expression.—A second dysgenesis experiment was carried out involving an ry + transposon inserted in polytene section 16D on the Χ chromosome. A minimal estimate of the relative frequency of imprecise excisions, determined in this experiment is 75%.—A successful pilot experiment is described that utilizes dysgenic perturbation of the sdryry + allele to select for small deletions of the 5' noncoding region of the rosy locus.

Feeding and Excretion in the Scorpion Paruroctonus Mesaensis: Water and Material Balance

Scorpions feed by a process involving the external grinding and digestion of prey, with the ingestion of only the soluble fraction. The water obtained from the prey represents the most important source of water intake for scorpions inhabiting arid regions, placing great importance on the animals' ability to utilize prey water effectively. The scorpion Paruroctonus mesaensis (Stahnke) was found to ingest a mean of 88% of the body water of selected prey. However, the scorpion loses 0.37 ml of its own body water per ml of prey water extracted, resulting in a net water gain of 0.51 ml water for every ml of prey water. Fluid uptake by the scorpion has been ascribed to a pharyngeal pumping mechanism. Direct measurements of the suction generated by the pharynx yielded a minimal estimate of its pumping capability of 130mmHg. The uptake and excretion of nitrogen and electrolytes by Paruroctonus mesaensis on a diet of Tenebrio molitor adults were also analysed. Almost all the potassium ingested was excreted, whereas most of the sodium and chloride were retained, possibly serving to expand haemolymph volume. Assuming a steady state for nitrogen, it was estimated that the net utilizable water obtained from prey, that is the water intake minus the excretory water necessitated by nitrogen excretion, was equivalent to about 35% of the initial prey water or 69% of the water ingested.

Cholesterol at Birth and Age 1: Comparison of Normal and Hypercholesterolemic Neonates

Plasma cholesterol was evaluated at birth and at age 1 in 56 infants who had elevated cord blood cholesterol levels, and in 42 infants who had normal cord blood cholesterol levels. Both groups of infants came from a study of 1,800 unselected live births. Familial hypercholesterolemia was documented by three-generation transmission (from grandparent to parent to neonate) or by presence of tendinous xanthomatosis with hyper-beta-lipoproteinemia in eight neonates and kindreds. A minimal estimate of the heterozygote frequency of familial hyperlipidemia in unselected live births was 0.44% (8/1,800). On moderate-high cholesterol intake at age 1, three of four infants with familial hypercholesterolemia maintained distinctive elevations of plasma cholesterol. On low cholesterol diets, the distinction between four infants with familial hypercholesterolemia and normal or other hypercholesterolemic infants was blurred. Responsiveness to low cholesterol diet may hold promise in a long-term approach to normalization of plasma cholesterol in infants with familial hypercholesterolemia.

Spermatozoal Head Shape in Two Inbred Strains of Mice and Their Fl and F2 Progenies

Seven available inbred strains of mice-A, C57, SWR, C3H, 101, CBA, and DBA-were examined for differences in the shape of their spermatozoal heads. The two most extreme strains with respect to spermatozoal head shape were found to be SWR and C57. The Fl and F2 progenies derived from crossing C57 and SWR strains were found to be roughly intermediate between the parent inbred strains. Spermatozoal head shape for these preliminary investigations was calculated as outlined by Penrose (1953). Discriminant analysis was then carried out on F2 data and a linear discriminant function was obtained whereby 13 characteristics of the spermatozoal head were combined into one "super-character" or discriminant score. The numerical value of the discriminant score was taken as an estimate of spermatozoal head shape for each spermatozoon measured. 4nalyses of variance carried out on the discriminant scores for each generation revealed that intrastrain variation was not significant in the SWR strain and reached only low levels of significance in the C57 strain. The Fl males were found to be more variable than the inbred males. A large portion of the variability between the Fl males was shown to arise from "maternal effects". The F2 males were found to be much more variable than the Fl males and an estimate of heritability was approximately 0 -9. A minimal estimate of the number of "effective factors" operating to distinguish the two inbred parent strains was found to be two. The within-male variance was found not to differ significantly from generation to generation. The implications of these results are discussed.