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Biomedical subjects

R L Brown

Publications and source records attributed to R L Brown.

At least 127 records · Page 7Linked to original sources
PubMed1984

Comparative trial of six methods for the detection of CMV antibody in blood donors.

Six techniques were compared to find the most suitable method for determining the cytomegalovirus (CMV) antibody status of blood donors. Five hundred and ninety-six random sera were tested by immunofluorescence (IF), complement fixation (CFT), two enzyme linked immunosorbent assays (ELISA), a commercial indirect haemagglutination test (IHA)--used as supplied, and a locally devised micromodification of the same IHA test. Five hundred and thirty-five sera shared total agreement of results by all tests. The ELISA tests were the most discordant with other methods (10.5% discordancies both positive and negative). IF and CFT correlated well with other tests (0.8% discordances each) but for different reasons are unsatisfactory for donor screening. The IHA test used as supplied and its micromodification gave the most consistent results (0.8% and 0.5% discordancies respectively). The micromodification is easy to perform and read; it compares very favourably with CFT and IF for material costs and expertise required, and readily lends itself to the testing of large numbers of sera in a reasonable time. Within certain provisos the micro-IHA technique described is recommended as the most suitable test for blood donor screening.

Antibodies, Viral↗
PubMed1983

Development of a serum-free medium which supports the long-term growth of human and nonhuman primate lymphoid cells.

The ability to grow lymphoid cells in serum-free media affords the advantage of separately analyzing those components found to be involved in proliferation and differentiation. Iscove's medium (IMDM) supplemented with bovine serum albumin or casein, cholesterol, ferrous chloride, insulin, beta-mercaptoethanol, L-alpha-phosphatidylcholine, and transferrin supported the long-term proliferation of a gibbon ape lymphoma T-cell line, MLA144. These cells continue to produce interleukin 2 (IL-2, T-cell growth factor) constitutively in the serum-free medium. IL-2-dependent human T cells initiated and maintained in culture in serum-free medium containing IL-2 have continued to replicate for over 3 months with two population doublings every 3 to 4 days. A normal, IL-2-dependent marmoset T-cell line, OH-1, also proliferated on the serum-free medium when supplemented with IL-2. Several established primate B-cell lines which do not require IL-2 for growth were able to proliferate in the serum-free medium. These B-cell lines included B95-8, an Epstein-Barr virus (EBV)-transformed marmoset cell line, HuCo/R-H, a human cord B-lymphocyte line transformed with EBV, and Namalwa, an EBV-positive B-cell line established from a Burkitt's lymphoma. B95-8 cells grown on serum-free medium showed high levels of EBV antigen-positive cells after induction with 12-O-tetradecanoyl-phorbol-13-acetate (TPA).

Animals↗
PubMed1983

Audiometric monitoring of cis-platinum ototoxicity.

A prospective study was performed on 37 patients receiving 50 mg/m2 of cis-platinum every 3 to 4 weeks. These patients received a baseline audiogram evaluation and subsequent testing before each dose. Ototoxicity was noted to occur in 46% of the patients during therapy. Fourteen percent of this group showed a hearing loss in the speech frequency range. Four variables were analyzed to determine their correlative value for subsequent ototoxicity: (i) Pretreatment (baseline) audiograms, (ii) cumulative dose in milligrams, (iii) dosage in milligrams per square meter, and (iv) mean serum creatinine. Of these parameters, only a pretreatment abnormal audiogram was shown to have a prognostic value at a level of P = 0.095. Recommendations for audiometric monitoring of this high-risk group are discussed.

Adolescent↗
PubMed1982

The effect of T cell growth factor on the cell cycle of primate T cells.

The effect of T cell growth factor (TCGF) on the cell cycle of four T cell lines that differed in their response to TCGF was studied. Activated normal marmoset T cells (OH-1) were totally dependent on the addition of TCGF for long-term proliferation. In the absence of TCGF, the cells were incapable of traversing the cell cycle and became arrested in G1. The addition of TCGF to arrested OH-1 cells stimulated them to enter the S phase after a lag phase of 24 to 33 hr. The TCGF-stimulated cells reached a maximum of cells in the S phase by 12 hr after the initiation of DNA synthesis. TCGF was required for a minimum of 18 hr before cells would enter the S phase. In the absence of TCGF, activated owl monkey (8I) and human (RG) lymphocytes displayed a TCGF-sensitive block; addition of TCGF stimulated these cells to enter the S phase after 12 and 16 hr, respectively. In contrast, an owl monkey tumor-derived T cell line (OMT-1), not dependent on exogenous TCGF for proliferation, was able to progress slowly through the cell cycle without a TCGF-sensitive block. These cells responded to TCGF by showing an initial increase in cells that entered the S phase after a lag of 6 hr and a continuing movement of additional cells into S over the course of the next several hours.

Animals↗
PubMed1981

The value of breast self-examination.

In this study of 2092 women with cancer of the breast, those who had practiced breast self-examination (BSE) had earlier cancer than did those who had not practiced BSE. This was true for both black and white races, all educational and economic levels, each age group, and within each period of delay between first symptom and medical consultation. The practice of BSE increased as the educational level rose and diminished as age advanced. A higher percentage of whites than blacks used the procedure. Breast self-examination is safe and without cost to the women who practice it. It has the potential for helping more women to find their breast cancer early than any other method now available and feasible for widespread use.

Adult↗
PubMed1981

Sequence of events in the transformation process in cells infected with a temperature-sensitive transformation mutant of Moloney murine sarcoma virus.

Normal rat kidney cells infected with the temperature-sensitive transformation mutant of Moloney murine sarcoma virus were used to study the biochemical and morphological changes that occur during transformation. The infected cells exhibited a normal morphology at the nonpermissive temperature (39 degrees C) and a transformed morphology at the permissive temperature (33 degrees C). A new viral protein was detected 2 hr after shift to the permissive temperature as a polyprotein with an estimated Mr of 85,000 (p85). Scanning electron microscopy of the cells within 5 hr after shifting them to the permissive temperature showed that they became smaller and rounded with numerous elongated microvilli. In an earlier study, changes in hexose uptake were found to occur 8-12 hr after the shift [Horn, J. P., Wood, T. G., Blair, D. G. & Arlinghaus, R. B. (1980) Virology 105, 516-525]. By 48 hr, the cells had the morphology of a fully transformed cell. Concomitant with the changes in the morphology were alterations in the cytoplasmic microtubule complex. At the nonpermissive temperature, the complex consisted of a lacy network of microtubules. Within 5 hr at the permissive temperature, the lacy network was still present but the microtubules were more diffusely stained and less discernible. By 48 hr, the microtubules were so diffuse that the lacy network could not be recognized. Alterations in the F-actin cables did not occur until 24 hr after shifting the cells to the permissive temperature. Enucleation of the cells at the nonpermissive temperature and shifting the cytoplasts to the permissive temperature did not result in the synthesis of detectable p85 or in any alteration of the cytoplast morphology or microtubule complex, suggesting that the temperature-sensitive lesion affects some event occurring in the nucleus.

Animals↗
PubMed1981

A conversational information computer system for health and safety operation: the occupational surveillance interactive system (OSIS).

Collection, storage and retrieval of health and safety information is critical in occupational settings in making decisions about safety of employees and the healthful nature of the work environment. Computer surveillance programs have been utilized previously, but have been too complicated, too mathematical, and not directly accessible to health and safety personnel. This paper discusses the Occupational Surveillance Interactive System (OSIS), a conversational system which utilizes English instead of a computer language, and which provides immediate feedback to the health and safety practitioner through fact retrieval and statistical inference. Additionally, an algorithm is introduced which provides a predictive cueing for the development of some disease processes. The hypothetical example illustrated herein introduces a prototypal computer surveillance system, operating under an interactive mode, to provide the health and safety professional with a decision-making tool in occupational settings.

Computers↗
PubMed1981

Spontaneous release of a factor with properties of T cell growth factor from a continuous line of primate tumor T cells.

A continuous lymphoid cell line had been previously established from a gibbon with spontaneous lymphosarcoma. This cell line, designated as MLA144, when tested after several years in culture was shown to release spontaneously a factor biologically and biochemically similar to human T cell growth factor (TCGF). Conditioned media (CM) from MLA144 cells support growth and DNA synthesis of T cells from humans, several other species of primates, and also from mice and rabbits. The activity in the MLA144 CM is resistant to 60 degrees C and to low and high pH, has a m.w., as determined by gel filtration, of 21,500, elutes from DEAE-cellulose at 0.04 to 0.06 M sodium phosphate buffer, pH 7.6, and has an isoelectric point of about 6.45. Surface-marker analysis of MLA144 cells by rosetting techniques indicates that they are T cells lacking in the receptor for the Fc portion of IgG. The release of TCGF by MLA144 cells should have practical value in terms of ease of TCGF production and should be of great help in the facilitation of studies on the cell biology and molecular biology of TCGF production.

Animals↗
PubMed1980

Genetic manipulation by means of microcell-mediated transfer of normal human chromosomes into recipient mouse cells.

Microcell-mediated chromosome transfer is an innovative approach to the production of karyotypically simple hybrids. This method of gene transfer, employing micronuclei formed by prolonged Colcemid treatment, has been utilized for rodent systems. Expansion of this technology to include transfer of normal human genetic material has been hindered because large micronucleate populations from diploid human cells have been unobtainable. This report describes the production of micronuclei in 40-60% of normal human fibroblasts. These micronucleated cells have been enucleated by combining centrifugation and cytochalasin B treatment, and the resultant microcells have been purified and fused to recipient mouse (LMTK-) cells. Microcell hybrid clones containing a single human chromosome have been isolated from three separate fusion experiments. The time course for production of these hybrids, from fusion to karyotypic analysis, was 6 weeks. With a transfer frequency of about 2 x 10(-6), a single intact human chromosome has become a functioning element of the murine genome.

Animals↗