PubMed Health⌕ Search

Biomedical subjects

J Keddie

Publications and source records attributed to J Keddie.

8 recordsLinked to original sources
PubMed2000

Arabidopsis transcription factors: genome-wide comparative analysis among eukaryotes.

The completion of the Arabidopsis thaliana genome sequence allows a comparative analysis of transcriptional regulators across the three eukaryotic kingdoms. Arabidopsis dedicates over 5% of its genome to code for more than 1500 transcription factors, about 45% of which are from families specific to plants. Arabidopsis transcription factors that belong to families common to all eukaryotes do not share significant similarity with those of the other kingdoms beyond the conserved DNA binding domains, many of which have been arranged in combinations specific to each lineage. The genome-wide comparison reveals the evolutionary generation of diversity in the regulation of transcription.

Amino Acid Motifs↗
PubMed1981

The withdrawal of centrally acting antihypertensives in dogs.

1. The effects of the withdrawal of clonidine and 6-(2-chloro-6-fluoro-phenyl)-2,3,6,7-tetrahydro-5H-pyrrolo-(1,2-a)-imidazole hydrobromide (ICI 106270) on the blood pressure and heart rate of chronically dosed beagle dogs has been investigated. 2. The control heart rate was 75.4 beats/min and it varied considerably during therapy with clonidine (100-200 microgram/kg orally 2 X or 3 X daily for 10 days). 3 h after dosing it was always depressed, this reduction varying from 48.5% on day 1 to 32.2% on day 9. The heart rate was depressed 8 h after the initial dose but by day 9 heart rate was 37.6% above control at this time. 3. On withdrawal of clonidine heart rate displayed a marked rebound which reached a maximum of 59.9% above control 16 h after the last dose. 4. During clonidine treatment diastolic blood pressure fell by 23.3% from a control of 87.4 mmHg and on withdrawal it returned to control with no overshoot. 5. During treatment with ICI 106270 (600 microgram/kg orally 3 X daily for 10 days) heart rate did not rise above the control level of 88.9 beats/min and diastolic blood pressure was decreased 21.6% from a control value of 113.7 mmHg. 6. On withdrawal of ICI 106270 both blood pressure and heart rate returned to control levels without any overshoot. 7. The tachycardia on withdrawal of clonidine in dogs occurred with every animal treated and may represent a useful model for assessing the likelihood of other centrally acting antihypertensives to produce rebound in man. In this test situation ICI 106270 did not produce rebound tachycardia.

Animals↗
PubMed1975

Plasma renin activity during and after dynamic and static exercise.

The effect of dynamic and static exercise on plasma renin activity was investigated in three normal males. Near maximal supine exercise for 10 min on a bicycle ergometer caused a small increase in plasma renin activity during exertion with a much larger increase during recovery which reached a peak between 10-20 min. Supine exercise at half this level and static exercise (hand-grip) had no detectable effect on plasma renin activity.

Heart Rate↗
PubMedDate not supplied

The role of angiotensin in the control of blood pressure during sodium depletion.

Sodium depletion was induced in dogs to raise plasma renin activity (PRA) from 1.11 to 26.48 ng/ml/hr. Little overall change in blood pressure (BP) occurred, but cardiac output (CO) and central venous pressure fell, while total peripheral resistance and heart rate (HR) increased. A nonapeptide converting enzyme inhibitor (CEI) produced a fall in BP which was linearly related to log. PRA; the intercept with PRA was at 1.05 ng/ml/hr, close to the average value for dogs on a normal diet. The fall in BP with this agent was not accompanied by an increase in HR or CO. When Sar1-Ala8 angiotensin II was used to antagonize the action of angiotensin, the fall in BP was also linearly related to log. PRA. However, for a given level of PRA this fall in BP was less than that achieved with CEI and the intercept of BP fall with PRA was 2.6 ng/ml/hr. Again with this agent there was little change in HR or CO as BP was reduced. Thus, both antagonists lowered peripheral resistance without exciting the homeostatic reflexes indicating that, as PRA rose above the normal resting level, the angiotensin generated had both a direct and indirect effect in maintaining BP.

Angiotensin II↗