Biomedical subjects

J Ness

Publications and source records attributed to J Ness.

12 recordsLinked to original sources

PubMed1994

The assessment of the HO. scavenging action of therapeutic agents.

A new method is reported for the assessment of the HO. scavenging action of therapeutic agents. It is based on the photolysis of zinc oxide and has a detection limit of 3.3%. The scavenging order of the compounds tested was penicillamine > rentiapril > ascorbic acid > cysteine > glutathione > thiomalic acid > N-acetylcysteine > myocrysin > methionine. None were as effective as DMSO. It is argued that these compounds can have an in vivo protective effect where HO. is produced from oxidant producing cells, thus limiting radical induced damage.

Azo Compounds↗

PubMed1991

Specific identification and subcellular localization of three calmodulin-binding proteins in the rat gonadotrope: spectrin, caldesmon, and calcineurin.

In an effort to characterize the second messenger system for LH release, we have previously identified five calmodulin-binding proteins in rat gonadotropes of Mr greater than 205,000, 200,000, 135,000, 60,000, and 52,000. In the present study, we have used a calmodulin overlayer assay combined with Western blotting to determine the molecular identity of three calmodulin-binding proteins in rat gonadotropes: the alpha subunit of spectrin (Mr greater than 205,000), caldesmon (Mr 84,000), and the alpha subunit of calcineurin (Mr 60,000). The Mr greater than 205,000 and Mr 60,000 components or rat pituitary which bind calmodulin are immunoreactive with spectrin and calcineurin antisera, respectively. Rat pituitary also contains an Mr 84,000 component, which is immunoreactive with polyclonal sera and monoclonal antibody raised to chicken gizzard caldesmon (Mr 150,000). Like caldesmon from other sources, the Mr 84,000 component remains soluble after heat treatment and preferentially binds either filamentous actin or calmodulin, depending on the Ca2+ concentration. The three calmodulin-binding proteins were localized specifically in gonadotropes using indirect immunofluorescence microscopy or by Western-blotting cell fractions enriched for gonadotropes. After differential centrifugation of pituitary homogenate, spectrin immunoreactivity was found associated with the nuclear and secretory granule fractions, whereas caldesmon immunoreactivity was seen in the cytosolic fraction and calcineurin in the cytosolic and nuclear fractions. Although the precise role for these proteins remains unknown, the apparent requirement for calmodulin and the small number of calmodulin-binding proteins in the gonadotrope suggest their involvement in mediating GnRH actions.

Animals↗

PubMed1990

Transducer manometry and the effect of body position on anal canal pressures.

Anal canal manometry is performed conventionally with balloons, sleeves, perfused or nonperfused open-tipped catheters, or with multiport probes. The authors constructed a new manometer with four transducers embedded in a probe (15 mm outside diameter) and oriented radially, 90 degrees apart. The transducer probe was validated in 27 healthy volunteers by comparing its performance to that of a standard four-port perfused manometer and then used to measure anal canal and rectal pressures in body positions more physiologic (standing, sitting) than that usually employed (left lateral) for such measurements. Both devices measured similar anal canal resting pressure in the left lateral position (mid canal, 58 +/- 3 mm Hg perfused vs. 62 +/- 4 mm Hg transducer; P greater than 0.05). The transducer probe, however, recorded higher squeeze pressures (mid canal, 100 +/- 6 mm Hg perfused vs. 143 +/- 14 mm Hg transducer; P less than 0.05). The transducer probe detected higher intrarectal and resting anal canal pressures when subjects were standing or sitting, compared with the left lateral position (rectum, 3 +/- 1 mm Hg left lateral; 17 +/- 2 mm Hg standing; 20 +/- 1 mm Hg sitting; P less than 0.05; mid anal canal, 57 +/- 3 mm Hg left lateral; 86 +/- 4 mm Hg standing; 81 +/- 5 mm Hg sitting, P less than 0.05). The rise in resting anal canal pressure was uniform circumferentially. Neither anal canal length nor squeeze pressure changed with change in position. The authors concluded that 1) transducer manometry recorded similar resting but higher squeeze pressures compared with perfused manometry; 2) transducer manometry recorded the same radial variation in anal canal resting and squeeze pressures as that recorded by the perfused manometer; and 3) standing and sitting caused a four-fold rise in intrarectal pressure, which was associated with a concomitant rise in resting anal canal pressure.

Adult↗

PubMed1990

Identification of a unique biological tumor marker in human breast cyst fluid and breast cancer tissue.

Breast cyst fluid from 35 women was stratified into risk groups based on personal and family history of breast cancer. Mitogenic activity in breast cyst fluid of women at highest risk to develop breast cancer was significantly higher than the activity in the lowest-risk group. There was a direct dose-dependent relationship between mitogenic activity and increased risk of developing breast cancer. Size-exclusion chromatography showed that breast cyst fluid from women at highest risk contained two peaks of growth factor activity: less than 6 kilodaltons (kd), identified as human EGF (epidermal growth factor), and 6 to 18 kd. Moderate-risk group samples demonstrated only the single less than 6 kd peak, whereas the lowest-risk group had insignificant growth-promoting activity. Breast cancer tissue analyzed in a similar manner revealed a predominant 6- to 14-kd peak of mitogenic activity demonstrating the same acid- and heat-stability found in breast cyst fluid.

Biomarkers, Tumor↗

PubMed1986

Structural studies on centromeres in the yeast Saccharomyces cerevisiae.

In the yeast Saccharomyces cerevisiae, circular or linear plasmids containing a functional centromere (CEN) and a chromosomal replicator (ARS) are mitotically stable and segregate as ordinary yeast chromosomes in the first and second meiotic divisions. A centromere in S. cerevisiae consists of a region of DNA, approximately 150 bp in length, containing three important sequence elements, which are folded with proteins into a specific conformation in the chromatin (the yeast kinetochore). Each of the functional CEN sequences contains a high (91% to 95%) AT region (element II), 78 to 86 bp in length, flanked on one side by the common sequence PuTCACPuTG (element I), and on the other by the sequence TGTTT.TG.TTTCCGAAA....AAA (element III). Deletions in the element II region partially inactivate mitotic function and cause precocious separation of the sister chromatids in meiosis I. Element III appears to be a protein binding site, as evidenced by the following observations. Various point mutations in element III inactivate centromere function, especially in the central CCG (17). One or more protein binding sites in the element III region can be demonstrated by an exonuclease III blocking assay. Wild-type CEN sequences compete strongly in this binding assay, whereas certain functionally inactive mutant CEN sequences do not. In addition, various DNA segments containing either CEN3 or the element III region strongly repress expression of the yeast GAL1 gene when inserted immediately upstream from the transcriptional start site. Helical DNA segments containing CEN3 or CEN14 are shown to be bent or distorted in shape in the high-AT element II region.

Base Sequence↗

PubMed1986

An analysis of social skills generalization in two natural settings.

The interactional behavior of two groups of elderly mentally retarded residents of a community facility was measured in two generalization situations before, during, and after one group received social skills training. The training group received social skills training within a game format, whereas the contrast group simply played a game with no emphasis on interactional behavior. Results suggested that generalization to natural interactional situations may be delayed following training and that it is more likely in some situations (i.e., with trained peers) than others (i.e., in the presence of untrained peers).

Aged↗

PubMed1985