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Biomedical subjects

K E Jones

Publications and source records attributed to K E Jones.

48 records · Page 3Linked to original sources
PubMed1991

Triiodothyronine receptor beta-2 messenger ribonucleic acid expression by somatotropes and thyrotropes: effect of propylthiouracil-induced hypothyroidism in rats.

mRNA for a thyroid hormone receptor isoform that is unique to the pituitary gland (TR beta-2) is down-regulated by T3. Increases in the expression of this mRNA are seen in rats rendered hypothyroid by treatment with propylthiouracil (PTU). This study used dual labeling to determine which pituitary cells expressed TR beta-2 mRNA in normal and PTU-treated rats. In situ hybridization protocols localized the mRNA (with biotinylated complementary oligonucleotide probes detected by avidin-biotin-peroxidase), and immunoperoxidase protocols identified the pituitary hormone proteins. In dispersed pituitary cells, 20 +/- 2% (average +/- SD) of cells from normal rats and 30 +/- 3% of cells from PTU-treated rats were labeled for TR beta-2 mRNA. PTU caused increases in the area of the labeled cells (from 114 +/- 11 to 225 +/- 7 microns 2), the area of the label per cell (from 27 +/- 3 to 71 +/- 11 microns 2), and label density. PTU produced increases in the percentage of TSH cells from 8 +/- 1% to 19 +/- 2%, decreases in the percentage of GH cells from 27 +/- 3% to 11 +/- 2%, and no change in other cell types. After dual labeling, 73% of cells that expressed TR beta-2 mRNA stored either TSH (35 +/- 8) or GH (38 +/- 6). Less than 10% stored other hormones. When each cell type was analyzed, 56 +/- 3% of TSH cells and 43 +/- 4% of GH cells expressed TR beta-2 mRNA. When these percentages were multiplied by the percentages of each cell type in the overall population, TSH and GH cells with TR beta-2 mRNA represented 6.8 +/- 1% and 11.6 +/- 1% of the pituitary cells, respectively. Less than 1% of all pituitary cells expressed TR beta-2 and ACTH (0.9 +/- 0.06), LH (0.8 +/- 0.1), FSH (0.8 +/- 0.1), and PRL (0.9 +/- 0.04). PTU treatment increased the percentage of TSH cells with TR beta-2 mRNA to 72 +/- 4% and decreased the percentage of GH cells with TR beta-2 mRNA to 30 +/- 3%. However, some enlarged putative TSH cells could not be identified by immunolabel because the storage levels were low. Thus, changes in TR beta-2 mRNA in hypothyroid rats may be the net result of the increase in the percentage of TSH cells, the amount of mRNA per cell (measured by area and density of label), and the decrease in the percentage of GH cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Isolation of a cDNA encoding human Rev-ErbA alpha: transcription from the noncoding DNA strand of a thyroid hormone receptor gene results in a related protein that does not bind thyroid hormone.

A cDNA encoding Rev-ErbA alpha, a member of the thyroid/steroid hormone receptor superfamily, has been isolated from a human fetal skeletal muscle library. This cDNA contains 269 consecutive base pairs identical to a region of a human c-erbA alpha-2 cDNA, but the respective long open reading frames utilize this nucleotide sequence in opposite orientations. Thus, human Rev-ErbA alpha (hRev) is derived from opposite-strand transcription of the c-erbA alpha genomic locus. mRNA encoding hRev was detected in human skeletal muscle by Northern analysis. Comparison of hRev and Rev-ErbA (rRev) reveals 99% identity in the putative DNA-binding and "ligand-binding" (carboxy-terminal) domains. hRev does not bind thyroid hormone (T3), as has also been found for its rat homolog. Interestingly, the human and rat Rev-ErbA alpha cDNAs are dissimilar at their 5' ends, corresponding to the first exon that we have identified in the rat gene. The conservation of the bidirectionally transcribed regions of c-erbA alpha-2 and Rev-ErbA alpha in human and rat suggests that this unusual genomic arrangement has an important function, perhaps related to the regulation of gene expression.

Base Sequence↗
PubMed1990

Gerontological research. Is it useful for nursing practice?

The potential usefulness to gerontological nursing practice of nursing as well as non-nursing research was studied. The empirical phase of nursing research was also compared with that of medical, behavioral science, and multidisciplinary research. Although the quantity of nursing research reviewed was small, nearly 80% was judged to be potentially useful to the practice of gerontological nursing. About one third of the non-nursing research was judged potentially useful. These findings are relevant to all nurses, indicating the value on non-nursing as well as nursing research to nursing practice. Overall, the design of nursing research compared favorably to the design of non-nursing research.

Geriatric Nursing↗
PubMed1990

A 100 electrode intracortical array: structural variability.

A technique has been developed for fabricating three dimensional "hair brush" electrode arrays from monocrystalline silicon blocks. Arrays consist of a square pattern of 100 penetrating electrodes, with 400 microns interelectrode spacing. Each electrode is 1.5mm in length and tapers from about 100 microns at its base to a sharp point at the tip. The tips of each electrode are coated with platinum and the entire structure, with the exception of the tips, is insulated with polyimide. Electrical connection to selected electrodes is made by wire bonding polyimide insulated 25 microns diameter gold lead wires to bonding pads on the rear surface of the array. As the geometrical characteristics of the electrodes in such an aray will influence their electrical properties (such as impedance, capacitance, spreading resistance in an electrolyte, etc.) it is desirable that such an array have minimal variability in geometry from electrode to electrode. A study was performed to determine the geometrical variability resulting from our micromachining techniques. Measurements of the diameter of each of the 100 electrodes were made at various planes above the silicon substrate of the array. For the array that was measured, the standard deviation of the diameters was approximately 9% of the mean diameter near the tip, 8% near the middle, and 6% near the base. We describe fabrication techniques which should further reduce these variabilities.

Animals↗
PubMed1986

The acquired immune deficiency syndrome: setting up a practical information network.

AIDS is a highly emotive subject. From the outset the problem was tackled openly, looking at it from a professional and a public point of view. Initially the programme was intended only to protect staff and manage patients effectively. It rapidly expanded to delivery an educational message, which deals with all aspects of the AIDS problem, to virtually all members of the community. This should help allay unnecessary anxiety and enhance communication. The incidence of AIDS infection in North Lincolnshire is low--there have not been any cases recorded. In these circumstances it may seem the efforts have been excessive. However, it is hoped that both staff and public have been reasonably well prepared to face the problem and help prevent its spread should the need arise.

Acquired Immunodeficiency Syndrome↗
PubMed1982

Epidemiologic study of refinery and chemical plant workers.

A dynamic retrospective cohort study was performed to examine the mortality experience of workers at Exxon's Baton Rouge, La refinery an chemical plant. Included were 8,666 regular employees who worked at least one month during the period Jan 1, 1970 through Dec 31, 1977, and retirees who were alive as of Jan 1, 1970. Mortality from all causes of death was lower than expected when compared with that of the U.S. population of similar age, sex, and race. Analyses of mortality by specific site of cancer revealed elevated standardized mortality ratios SMRs) for cancer of the kidney, testis, brain/central nervous system, pancreas, and lymphopoietic sites; none of these elevations was statistically significant. Because of the higher than average mortality from cancer of the pancreas in some Louisiana parishes and the observation that one additional death from cancer of the pancreas in this study would have resulted in a statistically significant SMR at the 95% confidence level, some emphasis was placed on this finding. No evidence was found to link cancer of the pancreas to a specific occupational group. An examination of mortality by occupational class revealed some elevated SMRs for further study.

Adult↗
PubMed1981

T1 bacteriophage as an indicator for decontamination of laminar-flow biological safety cabinets.

Type 1 coliphage dried onto a glass surface was used as an indicator to monitor decontamination of biological safety cabinets. When desiccated virus was treated with formaldehyde vapor (5,000 or 10,000 ppm) adjusted to 70 to 90% relative humidity immediately before testing, viral inactivation was slow for the first 50 min but then accelerated, being complete in the next 10 min. However, when virus was incubated in an atmosphere containing 70% humidity for 1 h before formaldehyde was added, inactivation was complete within 3 min, indicating that careful attention must be paid to relative humidity in decontamination of safety cabinets.

Containment of Biohazards↗
PubMed1977

Radiationless relaxation in "large" molecules: Experimental evidence for preparation of true molecular eigenstates and Born-Oppenheimer states by a coherent light source.

Photon absorption and emission by molecules that undergo radiationless transitions are examined using the single modes of lasers having well-defined coherence properties. Contrary to the usual beliefs, where it is assumed that the molecule is prepared in a Born-Oppenheimer singlet state and then "crosses-over" to other states (vibrationally "hot" singlets and/or triplets), it is shown experimentally that the true eigenstates of the molecule can be prepared, even in "large" molecules, if the laser correlation time is relatively long and the molecular relaxation is made slow. On the other hand, lasers with short (psec) correlation time have yielded effectively the singlet Born-Oppenheimer state, which has a much shorter lifetime than the true eigenstates. Effects of magnetic fields and temperature are also reported. The former changes the amount of mixing amongst the Born-Oppenheimer states. The latter, on the other hand, swings the molecule from being "small" (i.e., sparse vibronic structure with long lifetimes) to being "large" (i.e., dense statistical distribution of levels) since the relaxation between levels is very effective at high temperatures. Finally, the results of this work show that the words fluorescence and phosphorescence in their strict meaning are misleading if the true eigenstates, which may contain both singlet and triplet character, are prepared.

Journal Article↗
PubMedDate not supplied

A comparison of human motoneuron data to simulated data using cat motoneuron models.

The response of repetitively firing human motoneurons to a composite excitatory input was evaluated. It was clearly shown that the response of the motoneurons to the transient input decreased with an increase in the background firing rate of the cell. The current model of repetitively firing human motoneurons could not account for this experimental result. Therefore, a compartmental modelling approach was used to simulate the repetitive firing properties of anaesthetised cat motoneurons under current clamp conditions. The modelled motoneurons were used in simulations similar to the experimental paradigms where the response to a composite excitatory input was evaluated at different background firing rates. The motoneuron models also showed a decrease in response to the excitatory input at faster background firing rates. The results suggest that human motoneurons are more comparable to motoneurons in the anaesthetised cat preparation than formerly thought. The results also demonstrate that the apparent efficacy of a synaptic input may be modulated by changes in background firing rate of the postsynaptic neuron.

Animals↗