Biomedical subjects
T H Marshall
Publications and source records attributed to T H Marshall.
Liquid chromatographic assay for cerebrospinal fluid normetanephrine.
A method for quantitation of normetanephrine in human cerebrospinal fluid is described. An amine-specific reagent, sulfosuccinimidyl propionate, is used to obtain the lipid soluble N-propionyl derivative of normetanephrine, which can be separated and quantitated in presence of other biogenic amines by liquid chromatography with electrochemical detection. The method is reproducible, linear, and precise at the relatively low concentrations of unconjugated normetanephrine occurring in human cerebrospinal fluid. Hospitalized, drug-free, alcoholic patients were found to have cerebrospinal fluid unconjugated normetanephrine concentrations in the 0.5-1.5 nanomolar range. The practical limit of sensitivity for the method is about 0.025 pmole per ml of CSF.
Liquid chromatographic assay for cerebrospinal fluid serotonin.
A novel liquid chromatographic method was developed for accurate and precise routine quantification of serotonin in human cerebrospinal fluid. Serotonin is derivatized with an amine-specific reagent leaving its hydroxy group free for electrochemical detection and making it lipophilic enough for efficient extraction into organic solvents. The method is reproducible, linear and free of interferences by endogenous amines other than serotonin. The limit of sensitivity is 100 fmol/ml CSF or 20 parts per trillion. Serotonin concentrations in lumbar cerebrospinal fluid from drug free, depressed patients were in the low nanomolar range.
Asthma and diary/treatment cards.
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Cell surface receptors for endogenous mouse type C viral glycoproteins and epidermal growth factor: tissue distribution in vivo and possible participation in specific cell-cell interaction.
We have described previously the detection and tissue distribution of free cell surface receptors for ecotropic R-MuLV envelope glycoprotein and the growth factor EGF in vivo [1]. More recently, we have reported the chromosomal map position of the ecotropic viral receptor and its conservation between subspecies of the genus Mus [2]. This work has shown, for the first time, the presence of multiple, independently segregating cell surface receptor genes specific for different classes of ecotropic type C viral envelope glycoprotein. In this report we extend these findings and identify chromosome 2 as coding for the receptor used by M813, an ecotropic MuLV from a feral Asian mouse. This new receptor is probably also used by oncogenic, recombinant (MCF class) MuLV of C3H origin.
Regulation of expression of type C virion DNA polymerase (reverse transcriptase) in human x mouse and human x rat hybrid cells.
Human cells from 13 different individuals were fused to mouse and rat cells producing abundant type C viral particles. The results demonstrate that incorporation of active DNA polymerase (reverse transcriptase) into mature type C particles is suppressed in many of the hybrid clones but not in the parental mouse cell clones. This low particle-associated DNA polymerase phenotype was a heritable trait for over 100 cell generations but reversion to a high particle-associated DNA polymerase phenotype was possible. In contrast, no evidence for suppression of viral p30 antigen was found. These results suggest that human cells contain a factor(s) capable of interfering with the normal maturation of the mouse retrovirus DNA polymerase protein; however, it was not possible to assign this function to any of 20 different human chromosomes tested. It is suggested that these somatic cell hybrids may be useful in examining individual events in retrovirus packaging and release.
Genes controlling receptors for ecotropic and xenotropic type C virus in Mus cervicolor and Mus musculus.
Gene loci controlling cell surface receptors for murine leukemia virus were studied by using murine X Chinese hamster hybrid cells. Hybrids which exclusively segregate murine chromosomes were made by fusing Mus cervicolor and Mus musculus lymphocytes to hamster fibroblasts. Sensitivity to Moloney murine leukemia virus infecotion and specific binding of the envelope glycoprotein of Rauscher murine leukemia virus (gp70) cosegregate and isozyme analysis show an association with chromosome 5 in both species. With the possible exception of one clone, no evidence was found for a proviral integration site independent of chromosome 5. Evidence is presented for additional unlinked ectropic and xenotropic receptors independent of chromosome 5.
Gene mapping by somatic cell hybridization in species other than man.
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Gene mapping by somatic cell hybridization in species other than man.
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Chinese hamster X mouse hybrid cells segregating mouse chromosomes and isozymes.
Hybrid cells are readily formed by fusing clonal Chinese hamster cells to fresh, noncultured, adult mouse spleen cells followed by isolation in selective medium. The vast majority of such hybrids retain Chinese hamster chromosomes and isozymes while segregating mouse chromosomes and isozymes. The growth, plating efficiency, ease of karyology, and rapid segregation of mouse markers allows linkage tests in primary clones. Analysis of 13 isozymes showed 12 to be asyntenic and on epair (PGD-PGM2) to be syntenic This system will allow extensive somatic cell hybrid gene mapping in the mouse and permit a comparison of human and mouse linkage relationships.
Oncornavirus expression in human x mouse hybrid cells segregating mouse chromosomes.
Human x mouse hybrid clones obtained by fusing transformed human (VA2) cells with embryonic mouse brain cells were tested for their ability to spontaneously express type C virus particles. It had been previously shown that these hybrid cells preferentially retained human chromosomes while mouse chromosomes were lost. The culture fluid from one cell line was found to contain type C particle markers in abundance, and typical budding C particles were observed in the cells by electron microscopy. In contrast, no particle markers were detected in the culture fluid from parental cells and several other hybrid cell lines. Subclones of the virus-positive cell line continued to lose mouse chromosomes and were found to vary more than 100-fold in their culture fluid DNA polymerase activity. The hybrid cell viruses, termed HMV1, banded in a sucrose gradient between 1.14 and 1.16 g/ml, possessed viral group-specific antigens, and exhibited B-tropic host range for replication in mouse embryo cells, but did not replicate in human cells when directly applied. The virus did not transform mouse cells but was able to rescue the defective murine sarcoma virus from sarcoma-positive, helper-virus-negative cells. Activity of the DNA polymerase associated with HMV1 was similar to the activity of Rauscher murine leukemia virus (MuLV) DNA polymerase in its preference for poly(rA) over poly(dA) as a template, use of endogenous template, detergent requirement, and inhibition by antiserum directed against MuLV.DNA polymerase. The results suggest that human x mouse hybrid cells segregating mouse chromosomes can spontaneously express endogenous type C viruses and that such hybrid cell lines may be used for the isolation of latent mammalian oncornaviruses and analysis of viral gene regulation.
Activation parameters of elastase and chymotrypsin catalyzed hydrolysis. Differential role of favorable enthalpy in determining reactivity.
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The specificity of porcine elastase and -chymotrypsin. Effect of fatty acid chain length in a homologous series of nitrophenyl esters.
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Porcine elastase. I. The presence of tyrosinate-splitting enzymes as impurities in elastase preparations.
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Porcine elastase. II. Properties of the tyrosinate-splitting enzymes and the specificity of elastase.
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The elastase-catalyzed hydrolysis of p-nitrophenyl trimethylacetate.
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The determination of the concentration of hydrolytic enzyme solutions: alpha-chymotrypsin, trypsin, papain, elastase, subtilisin, and acetylcholinesterase.
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