DDAVP: does the drug have a direct effect on the vessel wall?

Evidence is presented that 1-deamino-8-d-arginine vasopressin (DDAVP), a vasopressin analog, has a direct effect on isolated vessel segments. The most significant finding is increased platelet adhesion and spreading at injury sites. An isologous human umbilical vein perfusion model was used to compare effects of DDAVP with those of epinephrine or zero drug controls. Scanning electron microscopy, in conjunction with morphometry, permitted quantification of platelet adhesion to subendothelium exposed by minimal injury in the model. In addition, umbilical vein effluents were tested for levels of factor VIII moieties (F VIII:C, F VIII:Rag, F VIII:RCof) and the prostanoids, 6 keto PGF1 alpha (stable metabolite of prostacyclin) and TXB2 (stable metabolite of thromboxane A2. Only F VIII:C from DDAVP treated segments was significantly (p less than 0.01) changed from controls.

Synthesis of the 5'-half molecule of yeast alanine tRNA

In this paper, we report the synthesis of the 5'-half molecule of yeast alanine tRNA (tRNAAlay) by ligating three oligonucleotide fragments corresponding to the nucleotide sequences 1-13, 14-22 and 23-35 respectively under the catalysis of T4 RNA ligase (Fig. 1). Because of the high purity of the oligonucleotide fragments and the excellent quality of T4RNA ligase and polynucleotide kinase we prepared, the isolation steps were simplified and the overall yields were much higher. The ligating yield of the docosamer (IV) was 75%, that of the pentatriacontamer (V), 90%, and the isolated yield of the final product was 21% calculated on the basis of the tridecamer (III) used in the first reaction. Under the action of T4 RNA ligase the synthetic 5'-half molecule was joined with the natural 3'-half molecule forming a semi-synthetic tRNAAlay, which possessed the biological activities of both accepting (3H)-alanine and incorporating it into proteins. The correctness of the structure of the synthetic 5'-half molecule was verified by both chemical analysis and biological activity assay.

Total synthesis of yeast alanine transfer ribonucleic acid

By a combination of chemical and enzymatic methods, small oligonucleotides with lengths varying from 2 to 8 nucleotides were synthesized from mononucleotides. The small oligonucleotides were then ligated with T4 RNA ligase into six large oligonucleotides (9 to 19 nucleotides long) which were further ligated to form two half molecules with 35 and 41 nucleotides respectively. Finally, the two synthetic half molecules were annealed and ligated to obtain the whole molecule of yeast alanine tRNA (tRNAAlay). Prior to this, two semi-syntheses were performed, i.e. ligation of the synthetic 5'-half molecule with the natural 3'-half molecule and that of the natural 5'-half molecule with the synthetic 3'-half molecule. Both the semi-synthetic tRNAAlay and the synthetic tRNAAlay occupy the same position as the natural tRNAAlay after electrophoresis on a 20% polyacrylamide gel. They have the same chemical composition (containing 9 modified nucleotides of 7 different species) and structure as the natural tRNAAlay and are biologically active, i.e. accepting and transferring alanine into proteins in a cell-free protein synthesizing system, the accepting activity of the synthetic product is 52-66% of that of the natural tRNAAlay and 91-106% of that of the reconstituted product of the two natural half molecules. The incorporation activity of alanine into proteins of the synthetic 3H-alanine tRNAAlay is 63%, corresponding to 91% of that of the natural tRNAAlay and 115% of that of the reconstituted product of the two natural half molecules. To the best of our knowledge, this is the first time that a natural RNA with biological activity is synthesized.

Integration, loss, and reacquisition of defective viral DNA in SV40-transformed mouse cell lines

We have examined the state of viral DNA in a set of SV40-transformed mouse cell lines. Using restriction enzymes which cut SV40 DNA in one place, we demonstrate that anchorage-independent SV40-transformed mouse cells commonly contain one or more detectable defective monomers of integrated viral DNA. The defective viral DNA in one of these cell lines, SV101, was extensively mapped using single and double enzyme digests. The results of this analysis indicate that SV101 contains nondefective viral DNA as well as defective viral DNA of the following sizes: 5.0, 4.3, 3.7, 3.4, and 1.5 kb. Three of these defective monomers (4.3, 3.7, and 1.5 kb) preserve the amino terminal exon of large T antigen, and two monomers (4.3, and 3.7 kb) preserve the little t coding region. Anchorage-dependent subclones of SV101 preferentially lose the defective viral DNA, while retaining an intact SV40 early region and the ability to express lytic-sized large and small T antigens. Despite a considerable amount of viral DNA rearrangement which accompanies subcloning, anchorage-independent subclones of SV101 retain defective viral DNA, especially the 4.3- and 3.7-kb monomers. Also, when an anchorage-independent subclone is selected from an anchorage-dependent revertant of SV101, it reacquires defective viral DNA, although of a size not seen in SV101. We conclude that defective viral DNA plays a role in generating the anchorage-independent phenotype. In earlier studies, we have reported that anchorage-transformed mouse lines contain a variant (100kDa) T antigen. The possible role of defective viral DNA in generating this T antigen is discussed.

Pulmonary function laboratory, the Mason Clinic

This laboratory, equipped to perform more than a score of different tests, provides diagnostic support for 125 board-certified physicians in joint private practice and for the 320-bed Virginia Mason Hospital. Nearly half of the 50 outpatients seen each day in the laboratory have been referred by physicians outside the Seattle area.

Plasticity of the parallel fiber-Purkinje cell synapse by spine takeover and new synapse formation in the adult rat

Alteration in synaptic connectivity between Purkinje cell spines and parallel fibers of the cerebellum were studied following partial deafferentation of Purkinje cells in the the adult rat. Transection of parallel fibers by two lesions placed at a 1 mm interval on the folial crest were used to produce degeneration of these afferents. Ultrastructural analysis of synapses on Purkinje cell spines revealed degeneration with vacating of postsynaptic sites within 6 h. Reactive synaptogenesis as takeover of Purkinje cell spines by formation of new synapses from remaining parallel fibers occurred even before degenerating parallel fibers had vacated postsynaptic sites. This was accompanied by a marked increase in the number of dual innervations by reactive parallel fibers within one day. Some vacated postsynaptic sites were lost as indicated by a reduction in the number of synapses and others may have been taken over by newly formed synapses on spines. In addition, new synapses formed between the shafts of Purkinje cell branchlets and parallel fibers. Sprouting of parallel fibers occurred as small extensions without tubules while Purkinje cell spines reacted by forming elongated and multiple heads which contacted different parallel fibers. After 5 days degenerating boutons were rarely found. Enlarged spine heads were each capped by a proportionally enlarged parallel fiber bouton and joined by an elongated synaptic junction to parallel fibers. Some parallel fiber boutons were greatly enlarged and capped numerous profiles of spines. This study shows that formation of new pre- and postsynaptic sites takes precedence over reoccupation of original contacts and that multiple synapses on individual spines are being eliminated to give rise to single contacts with boutons. This elimination resulted in enlargement of synaptic contact areas between Purkinje cell spines and parallel fibers by taking over postsynaptic sites from some vacated and eliminated boutons.

Constructions of gene libraries of Rana nigromaculata and Mus musculus with cosmid pHC79

Gene libraries of Rana nigromaculata and Mus musculus (C57J6) have been constructed by the cosmid system developed by Collins using BamHl and Pstl as cloning restriction enzymes. A simplified formula, which is a modification of Clarke and Carbon derived from approximation, was used for calculating the number of colonies or recombinants necessary for the construction of a gene library. Pro+ and leu+ complementary to the recipient cells (HB101) with the genetic constitution of pro- and leu- have been selected from the BamH1 gene libraries of both Rana nigromaculata and the mouse in the present work.

Nonlytic simian virus 40-specific 100K phosphoprotein is associated with anchorage-independent growth in simian virus 40-transformed and revertant mouse cell lines

Normal fibroblasts display two distinct growth controls which can be assayed as requirements for serum or for anchorage. Interaction of mouse 3T3 fibroblasts with simian virus 40 (SV40) thus generates four classes of transformed cells. We have examined viral gene expression in these four classes of cell lines. Immunoprecipitation of [35S]methionine-labeled cell extracts with an antiserum obtained from tumor-bearing hamsters detected the SV40 large T and small t proteins (94,000 molecular weight [94K], 17K) and the nonviral host 54K protein in all cell lines tested. A tumor antigen with an apparent molecular weight of 100,000 was also found in some, but not all, lines. Similar "super T" molecules have been found by others in many rodent transformed lines. We carried out an analysis of the relation of phenotype to relative amounts of these proteins in cell lines of the four classes, using the Spearman rank correlation test. The amount of the 100K T antigen relative to the 94K T antigen or to total viral protein was well correlated with the ability to form colonies in semisolid medium. No significant correlation was found between quantities of labeled 94K T antigen, 54K host antigen, or 17K t antigen and either serum or anchorage independence. Mouse cells transformed with the small t SV40 deletion mutant 884 synthesized a 100K T antigen, suggesting that small t is not required for the production of this protein. The 100K T antigen migrated more slowly than lytic T. Since mixtures of extracts from cells expressing and lacking the 100K T antigen yielded the expected amount of this protein, it is unlikely that the 100K T derives from the 94K protein by a posttranslational modification.

Pharmacokinetics of ceftriaxone in humans

Pharmacokinetics of the investigational cephalosporin ceftriaxone were studied after 30-min intravenous infusions of three ascending single doses of 0.5, 1, and 2 g crossed over in 12 normal subjects. Serially collected plasma and urine samples were analyzed for ceftriaxone by high-performance liquid chromatography. Plasma concentration-time profiles were characterized by a linear two-compartment open model with the following respective mean (+/- standard deviation) parameters at 0.5-, 1-, and 2-g dose levels: elimination half-life, 6.5 +/- 0.7, 6.2 +/- 0.8, and 5.9 +/- 0.7 h; apparent volume of distribution, 8.5 +/- 1.1, 9.0 +/- 1.1, and 10.1 +/- 1.0 liters; and plasma clearance, 929 +/- 150, 1,007 +/- 130, and 1,190 +/- 150 ml/h. The respective renal excretion parameters were as follows: renal clearance, 373 +/- 60, 399 +/- 50, and 533 +/- 128 ml/h; and percentage of dose excreted unchanged in the 48-h urine samples, 41 +/- 8, 39 +/- 5, and 43 +/- 10. The 6-h elimination half-life of ceftriaxone was 2- to 10-fold longer than those reported for marketed and other known investigational cephalosporins. The small dose-related increases in the apparent volume of distribution and clearance parameters can be explainhe 48-h urine samples, 41 +/- 8, 39 +/- 5, and 43 +/- 10. The 6-h elimination half-life of ceftriaxone was 2- to 10-fold longer than those reported for marketed and other known investigational cephalosporins. The small dose-related increases in the apparent volume of distribution and clearance parameters can be explainhe 48-h urine samples, 41 +/- 8, 39 +/- 5, and 43 +/- 10. The 6-h elimination half-life of ceftriaxone was 2- to 10-fold longer than those reported for marketed and other known investigational cephalosporins. The small dose-related increases in the apparent volume of distribution and clearance parameters can be explained by the concentration-dependent plasma protein binding of ceftriaxone in humans. The impact of the small dose-dependent changes in the pharmacokinetics of ceftriaxone is anticipated to be of negligible clinical significance.

Studies on the interaction of arylazido-beta-alanyl NAD+ with the mitochondrial NADH dehydrogenase

Arylazido-beta-alanyl NAD+ (A3'-O-(3-[N-(4-azido-2-nitrophenyl)amino]propionyl) NAD+) is a potent competitive inhibitor with respect to NADH (apparent Ki, 1.7-2.7 microM) for the purified mitochondrial NADH dehydrogenase (EC 1.6.99.3). Upon photoirradiation of the dehydrogenase in the presence of arylazido-beta-[3-3H]-alanyl NAD+, radioactivity was found to be associated with the Mr = 57,000 subunit without significant labeling of what are considered to be the enzyme's two smaller subunits. This labeling could be prevented by the presence of NADH during photoirradiation. In contrast to arylazido-beta-alanyl NAD+, arylazido-beta-alanyl NADP+ (N3'-O-(3-[N-(4-azido-2-nitrophenyl)amino]-propionyl) NADP+) did not inhibit dehydrogenase activity nor did photoirradiation of the enzyme in the presence of the radiolabeled analogue (arylazido-beta-[3-3H]alanyl NADP+) result in radioactivity being incorporated into the enzyme. It is concluded that the Mr -- 57,000 subunit contains the pyridine nucleotide-binding site of the mitochondrial NADH electron transport system.