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Biomedical subjects

J Collins

Publications and source records attributed to J Collins.

At least 397 records · Page 22Linked to original sources
PubMed1980

Oestrogen use and survival in endometrial cancer.

Of 860 women with endometrial cancer registered in a regional cancer treatment centre, 259 (30%) gave a history of oestrogen use for 6 months or more at some time before diagnosis, and 568 (66%) were non-users. OEstrogen use was associated with younger age, earlier stage, lower grade of tumour, less common myometrial invasion, and preferred treatment including radiation and hysterectomy. The 5-year survival of oestrogen users was 92 +/- 2% compared with 68 +/- 2% for non-users. Further analysis controlling for differences in the distribution of the variables associated with survival showed that for women who have endometrial cancer, the risk of any death for non-users is approximately 2-7 times greater than for oestrogen users, and the risk of death from endometrial cancer is 5.4 times greater for non-users. A history of oestrogen use is not associated with superior survival of women who have poorly differentiated tumours or myometrial invasion.

Adult↗
PubMed1980

Bronchoalveolar lavage for the preparation of free lung cells: technique and complications.

Bronchoalveolar lavage at fibreoptic bronchoscopy enables the peripheral bronchoalveolar free cell population, which consists mainly of lymphocytes and macrophages, to be sampled. The yield is sufficient for detailed morphological and functional investigation of these cells, which can be separated by exploiting the glass-adherent or phagocytic properties of macrophages. Such studies are of particular interest in patients with recurrent chest infections, to detect abnormalities of local cellular immunity; in pulmonary fibrosis to assess activity of the disease and effect of treatment by observing morphology and testing function of free lung cells; and in bronchial carcinoma to investigate local immune responses to the tumour. The procedure is held to be ethical in these circumstances. The lavage consists of irrigation of a segmental bronchus through the fibreoptic bronchoscope with up to 500 ml pH-corrected normal saline solution. It is contraindicated in those with respiratory or cardiac risk, but is tolerated well by most patients. Complications include acute respiratory distress, vasovagal syncope and fever with pulmonary infiltrates. Lavage is associated with a mean fall of PaO2 of 3.0 kPa (22.7 mmHg) and routine oxygen supplementation is recommended.

Cell Separation↗
PubMed1980

A small cosmid for efficient cloning of large DNA fragments.

The production and use of the 6 kb cosmid pHC79, a derivative of pBR322, is described. It can be used for cloning of fragments cleaved by EcoRI, ClaI, BamHI (also BglII, BclI, Sau3A and MboI), SalI (also XhoI and AvaI), EcaI and PstI. Hybrid cosmids containing inserts in the size range of 40 kb are packaged in vitro and transduced with an efficiency of 5 X 10(4) - 5 X 10(5) clones/microgram of insert DNA. Prefractionation of the DNA fragments to be cloned into 40 kb sized fragments ensures the cloning of contiguous stretches of DNA. Proteins produced in vitro by the cosmid pHC79 are identical to the ones produced by its pBR322 parent.

Bacteriophage lambda↗
PubMed1980

Restriction endonucleases or the site-specific DNA endonucleases.

Our present view of the site-specific endonucleases, which appear to be ubiquituous in the prokaryote kingdom, is probably heavily distorted by our search for tools for recombinant DNA technology. Only those enzymes having recognition sequences in the range of three to seven specific bases have been isolated. Of course the usefulness of these enzymes in the analysis of complex genomes, the rise of "reverse genetics", and the immediate breakthroughs in the area of gene expression in eukaryotes, particularly the understanding of tumour virus RNA processing and gene rearrangements in the expression of immunoglobulin genes has dominated the consciousness of the molecular and cell biologists during the last five years. There is a great diversity of staggering, symmetry, asymmetry and degeneration in the recognition sequences found. Taking into account also the genetic data on site-specific recombination and/or DNA degradation suggests that our present collection of endonucleases may only represent a narrow spectrum of specificities on an open-ended scale of complexity. The enzymes, themselves provide a rich pool to be exploited by the biophysicist and the biochemist to probe the subtleties of DNA-protein interaction.

Binding Sites↗
PubMed1979

Deletions, insertions and rearrangements affecting rpoB gene expression.

Through cloning and deletion experiments on ColEl hybrids the rpoB gene (Rifr) was located on a physical restriction map; RNA polymerase binding studies showed no binding site within the structural gene. The genetic data and RNA polymerase binding studies lead to the conclusion that rp/L and rpoB are dependent upon a common promoter.

DNA-Directed RNA Polymerases↗
PubMed1979

Expression of Escherichia coli ribosomal protein and RNA polymerase genes cloned on plasmids.

Fragments of lambda drifd 18 DNA with different end-points within the set of structural genes of ribosomal proteins L11 (RPLK), Li (rplA), L10 (rplJ) and L12 (rplL) as well as the beta (rpoB) ANd beta' (rpoC) subunits of RNA polymerase have been cloned on plasmids. These plasmids were transformed in host cells which were mutant for each of the genes, enabling expression of both wild-type (plasmid-borne) and mutant (chromosomal) genes to be differentiated. On the basis of these results we propose the following genetic structure for the region: rplK and rplA are in one operon; rplL, rpoB and rpoC are in a second. Our data suggest the possibility that rplJ is by itself in an operon situated between the other two.

DNA, Recombinant↗
PubMed1979

Cell-free synthesis of proteins coding for mobilisation functions of ColE1 and transposition functions of Tn3.

A hybrid plasmid, pJC74, carrying the large (3.35 Md) EcoRI-PstI fragment of ColE1, the 1.3 and 1.8 Md PstI fragments of plasmid R1 drd19 (containing a part of Tn3 and known to specify transpostion functions), and a part of gamma bacteriophage DNA carrying the fused cohesive ends of gamma (cos) was constructed. Supercoiled DNA of pJC74 and a series of deletions (series pJC75) were used in a cell-free coupled transcription-translation system. Analysis of the proteins produced allowed the identification of a 28 to 30 kd protein and/or a 3 kd protein responsible for mobilisation of the plasmids in sex-factor-promoted conjugation. Furthermore, three protein bands of 12, 12.5 and 13 kd were correlated with the presence of a portion of the Tn3 transposon previously shown to code for transposition functions which can complement in trans. These latter and the 30 kd beta-lactamase were the only proteins identified as Tn3-specific by comparison of ColE1 with RSF2124.

Cell-Free System↗
PubMed1979

Providing health and social services to illegal alien families: a dilemma for community agencies.

Proposals for dealing with illegeal migration from Mexico to the United States generally do not recognize it as an international social problem. The proposals also present contradictory solutions. Amnesty, a humanitarian policy, is being suggested as well as increased restrictions and punishments, a policing policy. However, in the absence of a comprehensive national policy, community social and health care programs must provide services to illegal aliens. This article attempts to document some of the issues that illegal immigration presents for community agencies.

Child Health Services↗
PubMed1979

Possible priming effect of luteinizing hormone releasing hormone on the anterior pituitary gland in the Japanese quail and the stimulation of secretion of follicle-stimulating hormone.

After the i.m. injection of 10 micrograms synthetic LH releasing hormone (LH-RH) into Japanese quail the levels of LH and FSH in plasma rose significantly within 2 min. The increased level of LH declined rapidly but that of FSH was maintained for the duration of the experiment. To determine whether the anterior pituitary gland is primed by LH-RH a double injection schedule was adopted. It would appear that, while endogenous LH-RH may prime the avian pituitary gland slightly, synthetic LH-RH is ineffective.

Animals↗
PubMed1978

Altered DNA-protein relaxation complex in a replication mutant of plasmid ColE1.

Approximately 200,000 clones of Escherichia coli carrying mutagen-treated colicinogenic plasmid E1 (ColE1) were examined for irreversible loss of the plasmid at 43 degrees. Thirty of these clones that appeared to be most defective in plasmid DNA replication at the non-permissive temperature were selected for the study of: (a) the kinetics of plasmid and chromosomal DNA replication during a temperature shift in either the presence or absence of chloramphenicol; (b) the temperature stability of the plasmid DNA-protein relaxation complex; and (c) the temperature effect on F-promoted conjugal transfer. Two mutant plasmids, pJC307 and pJC301, showed defects in their relaxation complex. The relaxation complex of pJC307 exhibited an altered temperature stability in vitro. Reversion to temperature resistant replication resulted in four out of five cases in a concomitant change in the temperature stability of the relaxation complex. Conjugal mobility of this mutant was not markedly reduced at the permissive or non-permissive temperature. Plasmid pJC301 could not be isolated in the form of a relaxation complex and it was very poorly mobilized in an F'-promoted conjugation. These results indicate that the ColE1 plasmid codes for at least one of the proteins of the relaxation complex and that the relaxation complex is involved in ColE1 DNA replication. In addition, the properties of the mutant plasmid pJC301 are consistent with a role for the complex in the mobilization of ColE1 during conjugation.

Colicins↗