Differential effects of forest degradation on primate populations

A population survey of nonhuman primates in an area of northern Colombia was conducted using repeated systematic census techniques as well as exploratory transects. Both remnant forest patches and more extensive forests were examined for comparison. WhereasLagothrix andAteles were most numerous in extensive forests,Lagothrix was virtually absent in remnant forests.Cebus, Alouatta andSaguinus persist in remnant forests, and the last may even find second growth a favorable habitat. These results are in good agreement with independent studies in a second area in the South.     

Biochemical genetic analysis of pyrimidine biosynthesis in mammalian cells: I. Isolation of a mutant defective in the early steps of de novo pyrimidine synthesis.

The isolation and characterization of a new mutant of Chinese hamster ovary cells is described. This mutant, Urd-A, shows an absolute requirement for exogenously added pyrimidines for growth. Complementation analysis indicates that the lesion in this mutant is recessive. Revertants can be isolated at frequencies suggesting that it is a single gene alteration. Biochemical analysis of cell-free extracts of CHO-K1 (Urd+) and Urd-A revealed that Urd-A possesses no more than 10% of wild-type levels of carbamyl phosphate synthetase (EC 2.7.2.9) activity, no more than 1% of wild-type levels of aspartate transcarbamylase (EC 1.2.3.2) activity, and undetectable levels of dihydroorotase (EC 3.5.2.3) activity. Thus, this mutant appears simultaneously to possess marked or complete deficiencies in the activities of the first three enzymes of pyrimidine biosynthesis. Activities of the other enzymes of the pathway appear normal. The use of this mutant for biochemical-genetic studies of pyrimidine biosynthesis is discussed.     

NEUROCHEMISTRY OF THE SPINAL CORD IN EXPERIMENTAL BORDER DISEASE (HYPOMYELINOGENESIS CONGENITA) OF LAMBS

Abstract— The total lipid, cholesterol (free and esterified), cerebroside, phospholipid and fat-free dry matter contents were estimated in spinal cords of lambs affected with experimentally produced Border Disease. Comparisons were made with a healthy control group and with a group of lambs obtained from vaccinated ewes.
Clinically affected lambs showing tremors ('shaking'), a'hairy'birthcoat or both were found to possess one or two myelin lipid abnormalities. These were a generalised deficiency of myelin lipids (notably cerebroside) and the presence of abnormal quantities of esterified cholesterol. The former was particularly associated with the birthcoat defect and the latter with the neurological signs.
Previous exposure of the ewes to the infective agent (vaccination 28 days before mating) appeared to give considerable protection against the degenerative lipid changes and against 'shaking'but less against myelin dysgenesis and'hairiness'.     

Role for protein kinase C in A23187 induced glomerular arachidonate release and PGE2 production

A high concentration of the calcium ionophore A23187 (10 uM) stimulated release of labeled arachidonate and immunoreactive PGE2 from isolated superfused glomeruli. A lower concentration of A23187 (1 uM) or 12-0-tetradecanoyl phorbol-13-acetate (TPA, 0.1 uM), a direct activator of protein kinase C, when added alone was without effect on these parameters. Combined addition of A23187 (1 uM) and TPA (0.1 uM) synergistically stimulated arachidonate release and PGE2 production. 1-(5-isoquinolinyl)-2-methylpiperazine (H-7) a known inhibitor of protein kinase C in other tissues, suppressed increases in arachidonate release and PGE2 production mediated by A23187 (10 uM) or TPA plus A23187 (1 uM). H-7 inhibited while TPA stimulated protein kinase C activity that had been partially purified from soluble fractions of glomerular homogenates. These results support a role for protein kinase C in A23187 mediated arachidonate release.     

Determining pore size distribution in wet cellulose by measuring solute exclusion using a differential refractometer

Solute exclusion was used to determine the pore volume and micropore size distribution of wet cellulosic materials. Glucose, cellobiose, and polyethylene glycol (PEG) (8 to 130 A in diameter) were used as molecular probes. Four replicates of cellulosic samples, with each sample being analyzed 4 to 8 times, gave the concentrations of each molecular probe before and after contact with cellulose. Sugar concentrations were determined by the DNS method and PEG concentrations by a differential refractometer. Deviations arising from sample-to-sample variability result in variations of solute uptake from which the pore size distribution was determined. The need for replicate samples and a statistical approach to data analysis is indicated. Consequently, the data were fitted to an empirical logistic model function based on the minimum of the residual sum of squares using the finite-difference, Levenberg-Marquardt algorithm. A smooth increasing function resulted. We report experimental methodology employing a differential refractometer, common in many laboratories having a liquid chromato-graph instrument, combined with statistical treatment of the data. This method may also find application in determining pore size distribution in wet, hydrophilic polymers used in some types of membranes, chromatographic supports, and gel-type resins.     

Characterization of chromosomes with hybrid genes for Hb Lepore-Washington,Hb Lepore-Baltimore,Hb P-Nilotic,and Hb Kenya

Summary This study concerns the characterization of chromosomes with hybrid genes for Hb Lepore-Washington (44 chromosomes), for Hb Lepore-Baltimore (5 chromosomes), for Hb P-Nilotic (8 chromosomes), and for Hb Kenya (7 chromosomes) by determining a relatively large number of restriction enzyme polymorphism. Two, and possibly three, different Hb Lepore-Washington chromosomes were identified by specific haplotypes, while the haplotype of the Hb Lepore-Baltimore chromosome had its own characteristic pattern. A likely conclusion is that the crossovers leading to the formation of these chromosomes have occurred as independent events within the populations. Chromosomes with the -Lepore-Washington hybrid gene maintained specific characteristies (such as increased Hb F levels in heterozygotes, and high or low ^G values in this Hb F) which have been observed in normal individuals with chromosomes having comparable haplotypes. Only one haplotype was observed for each of the chromosomes carrying either the -P-Nilotic hybrid gene or the ^A hybrid gene of Hb Kenya.     

Effects of imidazole and indomethacin on fluid balance in isolated sheep lungs

We determined the effects of extracorporeal perfusion with a constant flow (75 ml . min-1 . kg-1) of autologous blood on hemodynamics and fluid balance in sheep lungs isolated in situ. After 5 min, perfusate leukocyte and platelet counts fell by two-thirds. Pulmonary arterial pressure (Ppa) increased to a maximum of 32.0 +/- 3.4 Torr at 30 min and thereafter fell. Lung lymph flow (QL), measured from the superior thoracic duct, and perfusate thromboxane B2 (TXB2) concentrations followed similar time courses but lagged behind Ppa, reaching maxima of 4.1 +/- 1.2 ml/h and 2.22 +/- 0.02 ng/ml at 60 min. Lung weight gain, measured as the opposite of the weight change of the extracorporeal reservoir, and perfusate 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) concentration increased rapidly during the first 60 min and then more gradually. After 210 min, weight gain was 224 +/- 40 g and 6-keto-PGF1 alpha concentration, 4.99 +/- 0.01 ng/ml. The ratio of lymph to plasma oncotic pressure (pi L/pi P) at 30 min was 0.61 +/- 0.06 and did not change significantly. Imidazole (5 mM) reduced the changes in TXB2, Ppa, QL, and weight and platelet count but did not alter 6-keto-PGF1 alpha, pi L/pi P, or leukocyte count. Indomethacin (0.056 mM) reduced TXB2, 6-keto-PGF1 alpha, and the early increases in weight, Ppa, and QL but did not alter the time courses of leukocyte or platelet counts. Late in perfusion, however, Ppa and QL were greater than in either untreated or imidazole-treated lungs.(ABSTRACT TRUNCATED AT 250 WORDS)