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Biomedical subjects

P Gray

Publications and source records attributed to P Gray.

At least 109 records · Page 6Linked to original sources
PubMed1982

"Developmental lag" in the evolution of technique for psychoanalysis of neurotic conflict.

The practice of psychoanalysis of neurotic conflict has not--to the extent that might be expected--evolved a consistent use in technique of available knowledge of the ego's mechanisms of defense. This is primarily related to a general resistance that can usefully be regarded as a "developmental lag." The evidence for this, particularly in Freud's writings, is reviewed as are the observations of others who have made note of this phenomenon. Some of the reasons that have contributed to this resistance among analysts are discussed.

Conflict, Psychological↗
PubMed1981

Leukocyte and fibroblast interferon genes are located on human chromosome 9.

At least eight leukocyte interferon genes (IFL) and the single fibroblast interferon gene (IFF) have been located on chromosome 9 in humans. In somatic cell hybrids of human and mouse cells containing a normal complement of mouse parental cell chromosomes but reduced numbers of human chromosomes, the human leukocyte and fibroblast interferon DNA sequences were present only when human chromosome 9 was also present.

Animals↗
PubMed1980

Integration of hepatitis B virus sequences and their expression in a human hepatoma cell.

Hepatitis derived from hepatitis B virus (HBV) infection is endemic throughout the world, but it is particularly prevalent in Asia and Africa. In these areas, demographic studies show a strong coincidence between HBV infection (assayed by HBV antigenic markers) and the incidence of primary liver cancer. On these grounds, a causal link between HBV infection and primary hepatocellular cancer has been proposed. Recently, a human hepatoma cell line (PLC/PRF/5; Alexander cells) has been shown to produce hepatitis B surface antigen (HBsAg). We show here that the Alexander cell line contains at least six (four complete and two partial) hepatitis B viral genomes integrated into high molecular weight host DNA. An analysis using specific probes to fragments of the HBV genome suggests that integration of the virus in most cases occurs at the nicked cohesive end region of the virus. Expression of viral sequences using Northern blots demonstrates the presence of RNA transcripts specific for the surface antigen sequences of HBV DNA and the absence of detectable transcripts corresponding to the hepatitis B core antigen.

Carcinoma, Hepatocellular↗
PubMed1980

A radio-immunoassay of 17-alpha-hydroxyprogesterone.

A method is described for the determination of 17 alpha-hydroxyprogesterone (17-OHP) in plasma. Antisera were raised in rabbits against 11-deoxycortisol-21-hemisuccinate-bovine serum albumin (11-DOC-21-HS-BSA) and 17 alpha-hydroxyprogesterone-3-carboxymethyloxime-bovine serum albumin (17-OHP-3-CMO-BSA). An antiserum to 11-DOC-21-HS-BSA exhibited cross-reaction with progesterone (29%), 11-deoxycortisol (100%), cortisol (17%) and testosterone (10%) and was therefore not appropriate for quantitation of 17-OHP in plasma. An antiserum to 17-OHP-3-CMO-BSA cross-reacted with progesterone (9,7%), 11-deoxycortisol (50%) and less than 1% with all other major naturally occurring steroid hormones. A radio-immunoassay (RIA) was developed using the antiserum to 17-OHP-4-CMO-BSA. The intra-assay and interassay coefficients of variation were 7,2% and 10,5% respectively. The normal ranges (nmol/l plasma) of samples extracted with hexane:benzene (1:1) and purified by Sephadex LH-20 chromatography were 0,28-4,7 for men, 0,84-3,0 for women (follicular phase), 3,0-11,0 for women (luteal phase), 4,6-22,1 for pregnant women, 18,5-123,9 for cord blood, 0,12-5,0 for children and 56,3-1 032 for persons with congenital adrenal hyperplasia (CAH) due to a 21-hydroxylation enzyme defect. Sephadex LH-20 purification of plasma extracts could be omitted when using the RIA as a screening procedure for CAH due to a 21-hydroxylation enzyme defect.

Adult↗
PubMed1980

Counting efficiency of some commercially available liquid scintillators compared.

We investigated four commercially available liquid scintillators as to overall counting efficiency and quenching effect of added phosphate-buffered isotonic saline. They differed significantly in these respects. Evidently, characteristics of the scintillator used in radioimmunoassays where beta-particle emitters are counted should be carefully examined if results are to be optimal.

Buffers↗
PubMed1979

Nucleotide sequence of the gene coding for the major protein of hepatitis B virus surface antigen.

DNA extracted from hepatitis B virus Dane particles has been cloned in bacteria using a plasmid vector. A full-length clone has been examined by restriction endonuclease analysis, and the nucleotide sequence of an 892-base pair fragment from cloned hepatitis B viral DNA encoding the surface antigen gene is reported. The amino acid sequence deduced from the DNA indicates that the surface antigens is a protein consisting of 226 amino acids and with a molecular weight of 25,398. The portion of the gene coding for this protein apparently contains no intervening sequences.

Antigens, Surface↗
PubMed1979

Structure-activity relationships in the development of hypoxic cell radiosensitizers. II. Cytotoxicity and therapeutic ratio.

This paper describes measurements of the aerobic cytotoxicity of 42 nitroaromatic and nitroheterocyclic compounds towards Chinese Hamster cells in vitro. The results of acute and chronic exposure were quantified, and the concentration C required to achieve a standard response estimated. Fitting the data to an equation of the form - log C = b0 + b1E, where E is the one-electron reduction potential, explained 47 and 71 per cent of the variance in the acute and chronic aerobic cytotoxicity respectively. The addition of further terms to the equation, quantifying partition properties, was not statistically significant. The coefficient b1 was similar for both acute and chronic exposure; the dependence of both cytotoxicity and radiosensitization efficiency on reduction potential was also similar. A therapeutic ratio derived from these in vitro measurements showed no dependence on redox or partition properties. The insensitivity of cytotoxicity and radiosensitization properties to variations in molecular structure, other than those which influence redox behaviour, offers exceptional flexibility in developing compounds of improved therapeutic ratio.

Animals↗
PubMed1978

Some factors affecting the specific toxicity of misonidazole towards hypoxic mammalian cells.

The toxic action of misonidazole towards hypoxic mammalian cells has been shown to be a function of serum concentration, with higher serum concentrations enhancing the toxic effect. Added thiols protect cells against misonidazole toxicity. In addition, the action of misonidazole on hypoxic cells labelled with 5-BUdR has been examined. Cells with incroported 5-BUdR are no more sensitive to misonidazole toxicity than are cells without label.

Blood↗
PubMed1978

Hepatotoxicity of salicylates in monolayer cell cultures.

The influence of graded doses of sodium salicylate on rat liver cells cultured in monolayers was assessed by measuring lactic dehydrogenase activity in a culture media after incubation. Morphological alterations were studied by electron microscopy. The influence of different albumin concentrations in the media on toxicity was also evaluated. Lactic dehydrogenase concentrations rose with increasing doses of salicylate up to 40 mg per dl. High concentrations of albumin were associated with reduced salicylate toxicity. These findings suggest that salicylate-induced hepatic injury is dose related and my be influenced by serum albumin levels

Albumins↗
PubMed1977

High energy fast neutrons from the Harwell variable energy cyclotron. I. Physical characteristics.

A high energy fast neutron beam potentially suitable for radiotherapy was built at the Harwell variable energy cyclotron. The beam line is described and results are given of physical measurements on the fast neutron beams produced by 42 MeV deuterons on thick (4 mm) and thin (2 mm) beryllium targets. With 20 muA beam current the entrance dose rate in a phantom 150 cm from the target was about 130 rad min-1 with the thick target and about 60 rad min-1 with the thin target. Therefore, it is possible to use both the thin target and the relatively large target-skin distance of 150 cm to improve depth dose for radiotherapy or radiobiology. With this arrangement the dose rate decreased to 50% at depths in the phantom of 11.3-15.4 cm, depending on the field size. The use of primarily hydrogenous materials for shielding and collimation provided beam edge definition similar to that of 60Co teletherapy units, and off-axis radiation levels of approximately 1% which compare favorably with 14 MeV deuteron-tritium generators. The copper backing of the thin target became highly radioactive and an alterative material may be preferable. Biologic characteristics of the beam are described in a companion paper.

Fast Neutrons↗