Search PubMed⌕ Search

Biomedical subjects

K Young

Publications and source records attributed to K Young.

At least 145 records · Page 8Linked to original sources
PubMed1989

The effect of diclofenac acid (Voltaren) on bleomycin-induced pulmonary fibrosis in hamsters.

Bleomycin is an anti-neoplastic compound which produces a time- and dose-dependent pulmonary fibrosis. The mechanisms which cause this fibrosis are not known. However, the ability of bleomycin to modulate prostaglandin synthesis, degradation and circulating levels appears to be central to the fibrosis. Previous studies, which have attempt to modulate bleomycin-induced fibrosis by prevention of prostaglandin synthesis have conflicting results. Therefore, the present study was designed to determine the effects of diclofenac acid, a nonsteroidal anti-inflammatory compound, on the development of bleomycin-induced pulmonary fibrosis. Diclofenac acid pretreatment and daily injections prevented lung collagen accumulation after intratracheal bleomycin. In addition diclofenac acid treatment resulted in significantly lower lung collagen level after intratracheal bleomycin at 14 and 21 days when compared with bleomycin alone. These data indicate that diclofenac acid treatment inhibits bleomycin-induced lung fibrosis possible through the prevention of prostaglandins synthesis.

Animals↗
PubMed1987

Chemotherapy of lymphoma in 75 cats.

Seventy-five cats with lymphoma were treated with combination sequential chemotherapy consisting of vincristine, cyclophosphamide, and methotrexate. Thirty-nine cats had mediastinal, 16 had multicentric, 14 had alimentary, and 6 had renal lymphoma. The median survival time of the 75 cats was 8 weeks, with a mean of 32 weeks. Sixty-two cats had follow-up evaluation until death or cure and had a median survival time of 7 weeks, with a mean of 37 weeks. Of the 62 cats, 32 (52%) attained complete remission, with a median remission duration of 16 weeks and a mean of 46 weeks. The addition of prednisolone and/or L-asparaginase to the protocol did not improve the results. Sixteen cats with multicentric lymphoma had the longest survival times (median, 18 months) and remission durations (median, 25 months). Prognostic factors were evaluated in each anatomic form of lymphoma.

Animals↗
PubMed1985

Trans acting regulation of beta globin gene expression in erythroleukemia (K562) cells.

K562 cells are induced by hemin to produce gamma and epsilon globin but not beta globin, although the beta globin gene is intact, and when isolated is expressed in a transient expression assay (1, 2). We have previously shown that an epsilon globin gene transferred into K562 cells is expressed and inducible (3). In this paper, we report the stable transfer of a sickle or betaS globin gene into K562 cells. Thirty-six different transformed lines were tested; 24 of 36 lines contained an intact betaS globin gene. However, using S1 nuclease, Dot blot, and Northern blotting analyses, none of these lines showed beta globin mRNA expression. These results indicate that trans acting factors are responsible for the lack of expression of the beta globin gene in K562 cells.

Cell Line↗
PubMed1985

Muscle weakness following sustained and rhythmic isometric contractions in man.

The effects of sustained and rhythmically performed isometric contractions on electrically evoked twitch and tetanic force generation of the triceps surae have been investigated in 4 healthy male subjects. The isometric contractions were performed separately and on different occasions at 30%, 60% and 100% of the force of maximal voluntary contraction (MVC). The area under the maximal voluntary contraction (MVC) force/time curve during the rhythmic and sustained contractions was the same for each experiment. The results showed that following rhythmic isometric exercise there was a small decrease in low (10 and 20 Hz) and high (40 Hz) frequency tetanic tension which was associated with % MVC. However, there was no change in the 20/40 ratio of tetanic forces, MVC or the contraction times and force of the maximal twitch. In contrast, following sustained isometric exercise tetanic forces were markedly reduced, particularly at low frequencies of stimulation. The 20/40 ratio decreased and the induced muscle weakness was greater at 30% than 60% or 100% MVC. The performance of sustained isometric contractions also effected a decrease in contraction time of the twitch and MVC. The results are in accord with previous findings for dynamic work (Davies and White 1982), and show that if isometric exercise is performed rhythmically the effect on tetanic tensions is small and there is no evidence of a preferential loss of electrically evoked force at either high or low frequencies of stimulation following the contractions. For sustained contractions, however, the opposite is true, the ratio of 20/40 Hz forces is markedly reduced and following 30% sustained MVC there is a significant (p less than 0.05) change in the time to peak tension (TPT) of the maximal twitch.

Adult↗
PubMed1985

The effects of two forms of isometric training on the mechanical properties of the triceps surae in man.

The training effects of rhythmic and sustained isometric contractions on the contractile characteristics of the triceps surae have been investigated in four healthy subjects over a period of 8 weeks. One leg (ST) of each subject was trained by performing repeated daily sustained (1 min) isometric contractions at 30% of maximal voluntary contraction force (MVC), and the other using rhythmic isometric contractions at 100% of MVC. The protocol was so arranged that the total area under the training force/time curves was the same for each limb. Electrically evoked maximal twitch (Pt) and tetanic (Po) tensions of the triceps surae were measured weekly on both legs using a standard procedure. The results showed that the rhythmic regime increased the MVC at the rate of 5.5% per week and the sustained training increased MVC at the rate of 3.3% per week. Twitch and tetanic tensions were not altered by either regime. However, only training using sustained contractions produced a progressive increase in endurance as measured by performance in a fatigue test. The results suggest that increases in voluntary strength resulting from short term isometric training are not necessarily associated with a rise in the intrinsic involuntary capacity of muscle fibres to generate force.

Adult↗
PubMed1985

Deletion and fusion analysis of the phage phi X174 lysis gene E.

The lysis gene, E, of bacteriophage phi X174 has been subjected to deletion and gene fusion analysis. C-terminal deletions of as few as 17 of the 91 codons inactivate the cloned E gene, which in its intact form can cause lysis of the host cell. Fusion of lacZ to deletion joints at the 59th codon or beyond apparently restores lethal and lytic competence to the respective E deletion alleles, whereas a fusion at the 23rd codon remains non-lethal. The lethal E phi lacZ fusions are also lethal to a mutant, designated slyD, which was isolated as a spontaneous E. coli mutant resistant to the expression of the intact E gene. slyD appears to be linked to rpsE. The data are interpreted in terms of a model in which E-mediated lethality requires oligomerization of the E gene product. Calculations based on the beta-galactosidase activity accumulated by the time of lethal action of E phi lacZ suggest that fewer than 1000 molecules of E gene product are required for lysis and probably fewer than 100 are required for loss of host viability.

Alleles↗
PubMed1985

Mechanical power output in children aged 11 and 14 years.

Short-term power output in jumping and cycling has been measured in 56 children aged 11 and 14 years. The results showed that the peak power output in cycling (Wb) and jumping (Wp) were closely associated (r = 0.91) but in absolute terms Wb was approximately 34% greater than Wb. There were no significant differences in Wb (or Wp) between the 11-year-old boys and girls, but the 14-year-old boys recorded approximately 25% higher power output values in cycling and jumping than girls of the same age and were approximately twice as powerful as their younger male counterparts. The velocity of movement in cycling (Vb) and jumping (VT) for a given age were identical and independent of sex in the younger children. Peak power output in cycling was reached when force and velocity were equivalent to 50% of their calculated maximal values. When Wb and Wp were related to an anthropometric estimate of leg muscle (plus bone) volume the difference in absolute power output between the children disappeared. The results suggest that the difference between Wp and Wb and the increase in absolute mechanical power output with age is mainly a function of size and the force which can be exerted at the optimal frequency of movement in children.

Adolescent↗