cDNA sequence of human beta-preprotachykinin, the common precursor to substance P and neurokinin A

The nucleotide sequence of cDNA encoding the human substance P precursor, beta-preprotachykinin (beta-PPT), has been determined. The source of mRNA was a human laryngeal carcinoid tumour that contained a high concentration of immunoreactive substance P. The human beta-PPT polypeptide is 129 amino acids long and contains regions encoding substance P and neurokinin A, each flanked by basic amino acid residues. Residues 72-107 of the human beta-PPT polypeptide encode the sequence of neuropeptide K, an N-terminally extended form of neurokinin A recently isolated from porcine brain.     

Leishmania donovani: cellular and humoral immune responses after primary and challenge infections in squirrel monkeys, Saimiri sciureus

Cellular and humoral immune responses were studied in squirrel monkeys after primary and challenge infection with a Khartoum strain (WR 378) of Leishmania donovani. Each of 7 squirrel monkeys, Saimiri sciureus, was inoculated intravenously with 5 X 10(7) amastigotes/kg body weight, and one other monkey (control) was inoculated with uninfected hamster spleen homogenate. Five infected monkeys recovered from visceral leishmaniasis and two infected monkeys died. Three of the five squirrel monkeys which recovered from the primary infection demonstrated acquired resistance when challenged with an intravenous inoculation of 1.0 X 10(8) amastigotes of L. donovani/kg of body weight. Each of these same three monkeys, the two remaining monkeys which recovered from the primary infection and an uninfected control monkey, were challenged subsequently with an intradermal injection of 2.2 X 10(7) promastigotes of L. braziliensis panamensis (WR539) and developed cutaneous lesions. The reactivity of peripheral blood leukocytes from infected squirrel monkeys to phytohemagglutinin was depressed 2 to 10 weeks after infection, and the reactivity to concanavalin A was not affected. Data on responses to pokeweed mitogen were inconclusive. Reactivity to leishmanial antigens was detected at 12 weeks after infection, which coincided with a marked decrease or disappearance of parasites in liver imprints. Two of five surviving squirrel monkeys developed weak delayed skin test responses to leishmanin antigens after 23 weeks; the three remaining monkeys were anergic during the primary infection but developed strong delayed skin test responses to leishmanin antigens at 7 weeks after a challenge with L. donovani. All squirrel monkeys inoculated with L. donovani developed a hyperproteinemia, hypergammaglobulinemia, hypoalbuminemia, and a reversal of the albumin/globulin ratio between 4 to 18 weeks after infection. Plasma IgM and IgG levels were increased between 2 to 18 weeks after infection; much of this increase was due to IgG. Class-specific antileishmanial antibodies, with generally low IgM and high IgG titers, reached a maximum after 14 and 16 weeks, respectively. A correlation was observed between concentration of gamma-globulins and plasma IgM and IgG levels, but not gamma-globulin concentrations and maximum titers of class-specific antileishmanial antibodies. Squirrel monkeys challenged with L. donovani again developed hyperproteinemia, hypergammaglobulinemia, and increased concentrations of plasma IgM and IgG which correlated with high titers of IgG class-specific antileishmanial antibody 4 weeks after reinoculation.(ABSTRACT TRUNCATED AT 400 WORDS)     

Regional Amino Acid Concentration in the Brains of Rats Exposed to High Pressures

Regional amino acid concentrations were measured in rat brain fixed by microwave irradiation at three levels of elevated atmospheric pressure corresponding to different phases of the high-pressure neurological syndrome [20 atmospheres absolute (ATA), no clinical signs; 60 ATA, tremor; 85 ATA, severe tremor and myoclonic jerks]. No changes in amino acid content occurred at 20 or 60 ATA. At 85 ATA glutamine content increased in hippocampus, striatum, cerebellum, and substantia nigra, and gamma-aminobutyric acid content increased in hippocampus. It is suggested that enhanced glutamate release in various subcortical structures contributes to the myoclonic activity observed at 85 ATA.     

Dilute acid hydrolysis of paper birch: kinetics studies of xylan and acetyl-group hydrolysis

Batch hydrolysis kinetics of paper birch (Betula papyrifera) xylan and its associated acetyl groups in dilute sulfuric acid have been measured for acid concentrations of between 0.04 and 0.18M and temperatures of between 100 and 170 degrees C. Only 5% of the cellulose was hydrolyzed for up to 85% xylan removal. Rate data were correlated well by a parallel reaction model based on the existence of reactive and resistant xylan portions. The resulting rate equation predicts the experimental xylan concentrations in the residue to within 10%. Hydrolysis of xylan-associated acetyl groups was found to occur at the same rate as that of xylan, except at 100 degrees C, where acetyl is released preferentially. No effect of acid concentration on the rate of acetyl removal relative to that of xylan was evident.     

Immunochemical detection and characterisation of osteocalcin from moa bone

Osteocalcin (the 6,000 dalton Mr gamma-carboxyglutamate-containing protein of bone) has been detected in acid extracts of bones of the extinct class of New Zealand ratite birds, the moas, using a radioimmunoassay for sheep osteocalcin. The immunoreactive osteocalcin of the extracts of two of these bones (the fibulae from two specimens of Pachyornis elephantopus found in South Island swamps) has been fractionated by gel filtration chromatography and reversed-phase high performance liquid chromatography, and behaves in a manner characteristic of osteocalcin from modern bones. Carbon-14 dating of bones and gizzard contents found in association with these specimens indicates approximate ages of 3,600 and 7,400 years respectively.     

Elevated levels of erythrocyte hypoxanthine phosphoribosyltransferase associated with allelic variation of murine Hprt

Murine stocks with wild-derived hypoxanthine phosphoribosyltransferase (HPRT) A alleles (Hprt a) have erythrocyte HPRT activity levels that are approximately 25-fold (Mus musculus castaneus) and 70-fold (Mus spretus) higher than those of laboratory strains of mice with the common Hprt b allele (Mus musculus: C3H/HeHa or C57B1/6). Since the purified HPRT A and B enzymes have substantially similar maximal specific activities (64 and 46 units/mg of protein, respectively), we infer that these HPRT activity levels closely approximate the relative levels of HPRT protein in these cells. Red blood cells of HPRT A and B mice have similar levels of adenine phosphoribosyltransferase activity (APRT; EC 2.4.2.7) and reticulocyte percentages, which suggests that the elevated levels of HPRT in erythrocytes of HPRT A mice are not secondary consequences of abnormal erythroid cell development. The HPRT activity levels in reticulocytes of HPRT B mice are approximately 35-fold higher than the levels in their erythrocytes and approach the HPRT activity levels in reticulocytes of HPRT A mice. Thus, the marked differences in the levels of HPRT protein in erythrocytes of HPRT A and B mice result from differences in the extent to which the HPRT A and B proteins are retained as reticulocytes mature to erythrocytes. The substantial and preferential loss of HPRT B activity from reticulocytes is paralleled by an equivalent loss of HPRT immunoreactive protein (i.e., CRM) from that cell, and we infer that the HPRT B protein is degraded or extruded as reticulocytes mature to erythrocytes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Specific detection of α-amylase activity in crude plant extracts after isoelectric focusing

A new method which utilizes Procion Red MX 2B amylopectin for the detection of α-amylase in crude plant extracts is described. The substrate is specific only against α-amylase hydrolysis and β-amylase does not attack it. Paper containing Procion Red MX 2B amylopectin applied to gels after isoelectric focusing reveals α-amylase isoenzymes as white bands. When this technique is used, heat-inactivation of β-amylase is not required.     

DNA-mediated gene transfer of a mutant regulatory subunit of cAMP-dependent protein kinase

We have used DNA-mediated gene transfer of genomic DNA to introduce into wild-type Chinese hamster ovary (CHO) cells a mutant gene that confers resistance to the growth inhibitory effect of cAMP. This dominant mutation in CHO cell line 10248 is responsible for an alteration in the RI subunit (RI*) of the type I cAMP-dependent protein kinase (Singh, T. J., Hochman, J., Verna, R., Chapman, M., Abraham, I., Pastan, I.H., and Gottesman, M.M. (1985) J. Biol. Chem. 260, 13927-13933). The transformant 11564 which was studied in detail, has the same characteristics as the original mutant 10248 including continued growth in medium containing 8-Br-cAMP, an increase in the Ka for cAMP activation of the kinase, a greatly reduced amount of type II protein kinase activity, an altered incorporation of the photoaffinity label 8-N3[32P]cAMP into the RI* subunit of PKI, and an absence of cAMP-dependent phosphorylation of a Mr = 52,000 protein in intact cells. In addition, analysis of the DNA of the transformant indicates the presence of an increased amount of DNA for the RI gene. These results are consistent with the transfer of a mutant gene for the RI* subunit of the cAMP-dependent protein kinase and its phenotypic expression in the transformant and also support the hypothesis that the mutation responsible for the defect in cell line 10248 is due to an alteration in the gene for RI.     

Effect of elastic loading on ventilatory pattern during progressive exercise

Ventilatory responses to progressive exercise, with and without an inspiratory elastic load (14.0 cmH2O/l), were measured in eight healthy subjects. Mean values for unloaded ventilatory responses were 24.41 +/- 1.35 (SE) l/l CO2 and 22.17 +/- 1.07 l/l O2 and for loaded responses were 24.15 +/- 1.93 l/l CO2 and 20.41 +/- 1.66 l/l O2 (P greater than 0.10, loaded vs. unloaded). At levels of exercise up to 80% of maximum O2 consumption (VO2max), minute ventilation (VE) during inspiratory elastic loading was associated with smaller tidal volume (mean change = 0.74 +/- 0.06 ml; P less than 0.05) and higher breathing frequency (mean increase = 10.2 +/- 0.98 breaths/min; P less than 0.05). At levels of exercise greater than 80% of VO2max and at exhaustion, VE was decreased significantly by the elastic load (P less than 0.05). Increases in respiratory rate at these levels of exercise were inadequate to maintain VE at control levels. The reduction in VE at exhaustion was accompanied by significant decreases in O2 consumption and CO2 production. The changes in ventilatory pattern during extrinsic elastic loading support the notion that, in patients with fibrotic lung disease, mechanical factors may play a role in determining ventilatory pattern.