Search PubMed⌕ Search

Biomedical subjects

J R Miller

Publications and source records attributed to J R Miller.

At least 235 records · Page 13Linked to original sources
PubMed1975

Detection of nonintegrated plasmid deoxyribonucleic acid in the folded chromosome of Escherichia coli: physiochemical approach to studying the unit of segregation.

Physiocochemical evidence presented indicates plasmid deoxyribonucleic acid (DNA) can associate with host chromosome without linear insertion of the former into the latter. This conclusion is based on the observation that covalently closed circular (CCC) plasmid DNA can cosediment with undegraded host chromosome in a neutral sucrose gradient. When F plus bacteria are lysed under conditions that preserve chromosome, approximately 90% of CCC F sex factor plasmid (about 1% of the total DNA) is found in folded chromosomes sedimenting at rates between 1,500 and 4,000s. The remaining 10% of the CCC F DNA sediments at the rate (80S) indicative of the free CCC plasmid form. Reconstruction experiments in which 80S, CCC F DNA is added to F plus or F minus bacteria before cell lysis show that exogenous F DNA does not associate with folded chromosomes. In F plus bacteria, F plasmid is harbored at a level of one or two copies per chromosomal equivalent. In bacteria producing colicin E1, the genetic determinant of this colicin, the Col E1 plasmid, is harbored at levels of 10 to 13 copies per chromosomal equivalent; yet, greater than 90% of these plasmids do not cosediment with the 1,800S species of folded chromosome. However, preliminary evidence suggests one or two Col E1 plasmids may associate with the 1,800S folded chromosome. Based on evidence presented in this and other papers, we postulate F plasmid can link to folded chromosome because the physicochemical structure of the plasmid resembles a supercoiled region of the chromosome and, therefore, is able to interact with the ribonucleic acid that stabilizes the folded chromosome structure. Implications of this model for F plasmid replication and segregation are discussed.

Carbon Radioisotopes↗
PubMed1975

Reaction of poliovirus RNAs with antibodies to double-stranded RNA demonstrated by an immunochemical binding assay.

An immunochemical binding assay was used to investigate the reactivity of radioactively labeled viral RNAs from poliovirus-infected cells with antibodies to the synthetic double-stranded RNA, poly(I)-poly(C). A RNase-free antibody-containing serum fraction was employed. Poliovirus replicative form reacted with the antibodies to poly(I)-poly(C) as well as or better than poly(I)-poly(C). Poliovirus replicative intermediate reacted with the antibodies to a greater extent than poliovirus single-stranded RNA, but both were less reactive than replicative form. The use of the immunochemical binding assay with sucrose-gradient fractions demonstrated that for both poliovirus single-stranded RNA and replicative form the peak of reactivity with the antibodies was coincident with the peak of radioactive material precipitated by trichloroacetic acid. The proportion of replicative intermediate that reacted with the antibody increased in sucrose-gradient fractions containing the more slowly sedimenting RI RNA.

Animals↗
PubMed1975

Advances in medical genetics.

Although advances in medical genetics are designed ultimately to help human beings receive better health care, they pose many problems for society. Some of these concerns are real, but others result from misunderstanding and/or misrepresentation of the true implication of certain developments in genetics. It is obvious that the geneticist must play a dual role in society as scientist and as advocate. Although such a duality or role is not easy, it is not impossible. However, it does mean that the training of the medical geneticist must include more than exposure to the scientific approach.

Biomedical Research↗
PubMed1975

Optic nerve and retina after experimental circulatory arrest.

The retinas and optic nerves of late juvenile and adult Rhesus monkeys that had survived transient, total arrest of systemic circulation were normal when examined with the light microscope. The period of circulatory arrest ranged from 12 to 30 minutes and the subsequent survivals ranged from four hours to one year. The optic nerve and retina thus seem to share with the rest of the brain a surprising degree of resistance to damage from circulatory arrest.

Acid-Base Equilibrium↗
PubMed1975

The use of a registry case load survey in predicting trends in rehabilitative needs for the handicapped.

A special follow-up study of handicapped children was carried out to determine the level of residual disability in the caseload of the British Columbia Health Surveillance Registry. A total of 10,689 cases, aged seven or fourteen years were surveyed. Sixty-eight per cent of seven-year-olds and sixty-five per cent of fourteen-year-olds had a residual handicap. Of 3,131 seven-year-olds with a residual handicap, four per cent were not attending a school of any kind. Three per cent of the 4,094 fourteen-year-olds with a residual handicap were not attending school. These figures, along with prevalence statistics obtained through other Registry procedures provide useful minimal data for planning rehabilitative facilities for handicapped persons.

Adolescent↗
PubMed1973

Dermatoglyphics.

Explore the source record for details and available documents.

Animals↗