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Biomedical subjects

J F Scott

Publications and source records attributed to J F Scott.

At least 55 records · Page 3Linked to original sources
PubMed1982

Pain treatment in a palliative unit or team of a university hospital.

A Palliative Care Unit and Team provides a model for delivering care, in which narcotic analgesics can be optimally effective in the treatment of cancer pain. Our rapidly expanding knowledge of pain physiology and narcotic pharmacokinetics will not benefit patients unless we design more appropriate organizational structures to implement therapy and to teach symptom control. The Palliative Care Service model, as developed at several university hospitals in Canada, is designed to assist and complement oncology departments. Its primary role is to provide a consultation service to cancer patients wherever they may be in the health care system (home, O.P.D., hospital). A multi-specialty and interdisciplinary team offers assessment and therapy of pain and other symptoms. The McGill Pain Questionnaire is one useful tool in evaluating pain treatment. The Service also provides the university with a Palliative Care Unit designed for patients with advanced cancer who have complex symptomatology. Hospital organization must reflect the fact that environmental and psychosocial factors alter pain perception and response. Oral morphine is more effective when administered in a Palliative Care Unit than when it is given to patients in other settings. The Unit provides personnel skilled in analgesic titration and a supportive environment in which psychological, social and spiritual components of the pain experience can be evaluated and treated.

Environment↗
PubMed1982

Construction, replication, and chromatin structure of TRP1 RI circle, a multiple-copy synthetic plasmid derived from Saccharomyces cerevisiae chromosomal DNA.

Transformation studies with Saccharomyces cerevisiae (bakers' yeast) have identified DNA sequences which permit extrachromosomal maintenance of recombinant DNA plasmids in transformed cells. It has been hypothesized that such sequences (called ARS for autonomously replicating sequence) serve as initiation sites for DNA replication in recombinant DNA plasmids and that they represent the normal sites for initiation of replication in yeast chromosomal DNA. We have constructed a novel plasmid called TRP1 R1 Circle which consists solely of 1,453 base pairs of yeast chromosomal DNA. TRP1 RI Circle contains both the TRP1 gene and a sequence called ARS1. This plasmid is found in 100 to 200 copies per cell and is relatively stable during both mitotic and meiotic cell cycles. Replication of TRP1 RI Circle requires the products of the same genes (CDC28, CDC4, CDC7, and CDC8) required for replication of chromosomaL DNA. Like chromosomal DNA, its replication does not occur in cells arrested in the B1 phase of the cell cycle by incubation with the yeast pheromone alpha-factor. In addition, TRP1 RI Circle DNA is organized into nucleosomes whose size and spacing are indistinguishable from that of bulk yeast chromatin. These results indicate that TRP1 RI Circle has the replicative and structural properties expected for an origin of replication from yeast chromosomal DNA. Thus, this plasmid is a suitable model for further studies of yeast DNA replication in both cells and cell-free extracts.

Base Sequence↗
PubMed1980

D-Mannitol oxidation in the land snail, Helix aspersa.

Respiration by mitochondrial preparations from hepatopancreas tissue of the land snail Helix aspersa is stimulated by D-mannitol. The rate of mannitol-stimulated respiration is approximately one-half that given by succinate, the most effective substrate thus far tested with these preparations. Mannitol-stimulated respiration is cyanide-insensitive but is not inhibited by salicylhydroxamate. The product of the membrane-bound mannitol-oxidizing activity was shown to be D-mannose by thin layer chromatography, high voltage electrophoresis of the germanate and borate complexes, gas chromatography of the trimethylsilyl derivative, low resolution mass spectrometry of the trimethylsilyl derivative, and by an enzymatic method dependent upon phosphomannose isomerase. The reaction mannitol + O2 leads to mannose is stoichiometric; however, it is not known whether O2 is the immediate electron acceptor. The activity in Helix mitochondria is thus unique among most alditol-oxidizing enzymes in not being pyridine nucleotide linked and in acting on carbon 1 rather than carbon 2.

Alcohol Oxidoreductases↗
PubMed1979

Strategic intervention: a mental health program for the Hispanic community.

Over the past three years the Worcester Youth Guidance Center has developed a series of mental health programs directed to the Hispanic community of Worcester, Massachusetts. The model for these programs has been that of strategic intervention. This approach was based upon knowledge gained from the literature and extensive exploratory contacts with key Hispanic leaders. The Center's Hispanic Program consists of five components: (1) community education and training. (2) clinical consultation, (3) program consultation, (4) research, and (5) clinical intervention and case management. This article describes these components in detail and presents a rationale for strategic intervention.

Allied Health Personnel↗
PubMed1978

Purification of the rep protein of Escherichia coli. An ATPase which separates duplex DNA strands in advance of replication.

The product of the rep gene of Escherichia coli catalytically separates phiX174 duplex DNA strands in advance of their replication, utilizing ATP in the process (Scott, J. F., Eisenberg, S., Bertsch, L. L., and Kornberg, A. (1977) Proc. Natl. Acad. Sci. U. S. A. 74, 193-197). The enzyme has now been purified to near-homogeneity. Relatively large quantities were obtained from ColE1-plasmid-containing cells in which the enzyme level was 7 to 10 times above wild type. The assay for rep protein was based on its essential role, with phage-induced cistron A protein, in enzymatic synthesis of phage phiX174 (+) strands, using duplex circular DNA as template. The protein exhibits a molecular weight of 65,000 under denaturing and reducing conditions. The turnover number of the enzyme is approximately 6800 ATP molecules/min in strand separation as measured by extent of replication, or in an uncoupled reaction using single-stranded DNA effector.

Adenosine Triphosphatases↗
PubMed1978

ATP utilization by rep protein in the catalytic separation of DNA strands at a replicating fork.

Hydrolysis of ATP by rep protein proceeds in the presence of a single-stranded region of DNA 4 residues long, but the true effector for rep ATPase appears to be a replicating fork rather than a random coil. At or near a fork in duplex DNA, rep ATPase action is different from what it is on DNA lacking secondary structure (single-stranded): (i) Km for ATP is lower, (ii) specificity is for ATP and dATP with no action on other nucleoside triphosphates, (iii) sensitivity to certain ATP analogs is reduced, (iv) presence of a DNA-nicking enzyme (e.g. cistron A protein induced by phiX174) is required, and (v) Escherichia coli DNA binding protein facilitates rather than inhibits. During the separation of strands accompanying replication, 2 molecules of nucleoside triphosphate (ATP or dATP) are hydrolyzed for every nucleotide polymerized. Utilization of ATP by rep protein may provide energy for catalytic strand separation at a fork in advance of replication.

Adenosine Triphosphatases↗
PubMed1977

A mechanism of duplex DNA replication revealed by enzymatic studies of phage phi X174: catalytic strand separation in advance of replication.

The enzyme system for duplicating the duplex, circular DNA of phage phi X174 (replicative form) in stage II of the replicative life cycle was shown to proceed in two steps: synthesis of the viral (+) strand ]stage II(+)], followed by synthesis of the complementary (-) strand ]stage II(-)] [Eisenberg et al. (1976) Proc. Natl. Acad. Sci. USA 73, 3151-3155]. Novel features of the mechanism of the stage II(+) reaction have now been observed. The product, synthesized in extensive net quantities, is a covalently closed, circular, single-stranded DNA. The supercoiled replicative form I template and three of the four required proteins--the phage-induced cistron A protein (cis A), the host rep protein (rep), and the DNA polymerase III holoenzyme (holoenzyme)--act catalytically; the Escherichia coli DNA unwinding (or binding) protein binds the product stoichiometrically. In a reaction uncoupled from replication, cis A, rep, DNA binding protein, ATP, and Mg2+ separate the supercoiled replicative form I into its component single strands coated with DNA binding protein. In the presence of Mg2+, cis A, nicks the replicative form I; rep, ATP, and Mg2+ achieve strand separation with a concurrent cleavage of ATP and binding of DNA binding protein to the single strands. rep exhibits a single-stranded DNA-dependent ATPase activity. These observations suggest that the rep enzymatically melts the duplex at the replicating fork, using energy provided by ATP; this mechanism may apply to the replication of the E. coli chromosome as well.

Adenosine Triphosphatases↗
PubMed1977

X-linked Hunter syndrome: the heterozygous phenotype in cell culture.

Fibroblast cultures derived from the skin of three Hunter heterozygotes have been examined for iduronate sulfatase deficiency primarily by measurement of [35S]-mucopolysaccharide accumulation in the presence and absence of Hunter corrective factor. For each heterozygote, two populations of clones were observed: normal and enzyme deficient, as predicted by the Lyon hypothesis. However, the phenotype of the uncloned cultures was usually normal, presumably because of cross-correction, even after storage in liquid N2. Mixing experiments indicate that the presence of a majority of cells with the Hunter phenotype may be obscured as the result of correction by the minority population of normal cells in the mixture. Variability in the ability to cross-correct was also demonstrated. The unpredictable behavior of uncloned cultures make them unsuitable for diagnosing the Hunter carrier state.

Cells, Cultured↗
PubMed1976

Use of the Brompton mixture in treating the chronic pain of malignant disease.

Physical, psychological, financial, interpersonal and spiritual factors all modify the appreciation of chronic pain. The Brompton mixture is a highly effective, flexible, safe and convenient means of controlling the chronic pain of malignant disease. The mixture is a solution containing morphine; the dose of narcotic can be varied with the need for analgesia. It is given regularly, usually every 4 hours, with a phenothiazine, the main aims of therapy being prevention of pain rather than treatment, an unclouded sensorium and a normal affect.

Aged↗
PubMed1976

An enzyme system for replication of duplex circular DNA: the replicative form of phage phi X174.

Viral single strands (SS) are converted to the duplex from (RF) by a soluble enzyme fraction uninfected Escherichia coli [Schekman et al. (1975) J. Biol. Chem. 250, 5859-5865]. When reactions were supplemented with a soluble enzyme fraction from phi X174-infected cells, replication of phi X174 superhelical RF I DNA was observed. The activity supplied by infected cells was absent in cells treated with chloramphenicol or in cells infected with a phi X174 phage mutant in cistron A (cis A). A host function coded by the rep gene, essential in vivo for RF replication (but not for SS leads to RF), was supplied by enzyme fractions from either infected or uninfected cells. Based on complementation assays, the cisA-dependent and the rep-dependent proteins have each been purified about 1000-fold. The synthetic products of the enzymatic reaction were identified as RF I and RF II in which viral (+) and complementary (-) strands were newly synthesized.

Bacterial Proteins↗
PubMed1976

Enzymatic replication of viral and complementary strands of duplex DNA of phage phiX174 proceeds by seprate mechanisms.

Multiplication of the duplex, circular, phage phiX174DNA (replicative form, RF) in stage II of the replicative life cycle has been observed with a crude enzyme preparation [Eisenberg et al. (1976) Proc, Natl. Acad, Sci. USA 73, 1594-1597]. This stage has now been partially reconstituted with purified proteins and subdivided into two stages: II(+) and II(-). In stage II(+), viral (+) strand synthesis is carried out by four proteins: the phage-induced, cistron A-dependent protein, rep-dependent protein, DNA unwinding protein, and DNA polymerase III holenzyme. In stage II(-), complementary (-) strand synthesis utilizes the product of stage II(+) as template and the multiprotein system previously identified in the stage I synthesis of a complementary strand on the viral DNA template to produce RF. The multiprotein system includes DNA unwinding protein, proteins i and n, dnaB protein, dnaC protein, dnaG protein, and DNA polymerase III holoenzyme. A discussion of these two separate mechanism for synthesis of (+) and (-) strands suggests that they may account for essentially all the replicative stages in the life cycle of phiX174.

Bacterial Proteins↗
PubMed1976

Wheat bran in dyschezia in the aged.

A trial of wheat bran added to the diet of aged dyschezic hospital patients (12 men, 13 women) is reported. This significantly reduced the need for aperients and suppositories but revealed unexpected differences in response by sex. In men, bran produced more bowel actions, fewer constipated days and an increase in stool size. In women there was much less effect upon the number of bowel actions and reduction of constipated days. In men there were fewer constipated days and need for aperients after the bran was withdrawn. Side-effects were only seen in men. Most patients received 15 g/day (range 5-25 g/day). Although cheap and effective in replacing aperients, there were problems in administration and control of incontinence for the nursing staff. The value of added wheat bran in the bowel management of the long-stay hospital patient is discussed and an effective method of combining bran in the diet (e.g. with bread) might be further investigated.

Aged↗
PubMed1975

Regulation of histidine operon does not require hisG enzyme.

Mutations are described which delete all or part of the first structural gene (hisG) of the histidine operon of Salmonella typhimurium. Physiological regulation of histidine enzymes occurs normally in strains carrying any deletion that has both endpoints within the hisG gene. Constitutive high operon expression is observed in strains carrying any hisG deletion and an unlinked regulatory mutation, hisT1504. These results strongly indicate that the hisG protein is not an essential component of the mechanism for regulating expression of the histidine operon.

Cell Division↗