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Biomedical subjects

A Anderson

Publications and source records attributed to A Anderson.

At least 163 records · Page 9Linked to original sources
PubMed1990

The use of carvedilol in elderly hypertensive patients.

Carvedilol, a beta-blocking drug with vasodilator activity, has been used in 4 studies in 107 elderly patients with essential hypertension and has reduced blood pressure effectively. In the first study the pharmacokinetics and clinical response were compared between 21 patients greater than 65 years of age and 8 patients aged 35-50 years). The peak blood levels, time to maximal concentration, area under the curve, half-life and trough level of the drug with chronic administration did not differ. The clinical responses to the drug were similar, with a greater fall in systolic blood pressure in the older group. However the initial systolic blood pressure in the older group was higher. Carvedilol was compared with metoprolol, pindolol and nitrendipine in elderly patients. The responses to carvedilol were at least equal to those obtained with the other drugs. Control was achieved in the three studies with once-daily therapy. There was no significant postural hypotensive effect. A feature of all studies was the large number of patients who responded to carvedilol. The side-effect profile of the drug was acceptable; headache and dizziness were more common than with placebo or the comparison drugs and were frequently associated. There were no adverse biochemical effects and the lipid profile was not altered. Carvedilol is an effective antihypertensive drug that lowers blood pressure equally well in the young and the old.

Adrenergic beta-Antagonists↗
PubMed1990

Evidence for neutral and selective processes in the recruitment of enzyme-crystallins in avian lenses.

In apparent contrast to most other tissues, the ocular lenses in vertebrates show striking differences in protein composition between taxa, most notably in the recruitment of different enzymes as major structural proteins. This variability appears to be the result of at least partially neutral evolutionary processes, although there is also evidence for selective modification in molecular structure. Here we describe a bird, the chimney swift (Chaetura pelagica), that lacks delta-crystallin/argininosuccinate lyase, usually the major crystallin of avian lenses. Clearly, delta-crystallin is not specifically required for a functionally effective avian lens. Furthermore the lens composition of the swift is more similar to that of the related hummingbirds than to that of the barn swallow (Hirundo rustica), suggesting that phylogeny is more important than environmental selection in the recruitment of crystallins. However differences in epsilon-crystallin/lactate dehydrogenase-B sequence between swift and hummingbird and other avian and reptilian species suggest that selective pressures may also be working at the molecular level. These differences also confirm the close relationship between swifts and hummingbirds.

Amino Acid Sequence↗
PubMed1990

Simvastatin in the treatment of hypercholesterolaemia in patients with essential hypertension.

Mortality from coronary artery disease is a common problem in treated hypertensive patients, and these people have a high prevalence of elevated cholesterol levels. A study was undertaken to determine whether cholesterol could be lowered effectively without major side effects in patients with treated hypertension. Forty-nine patients (mean age 67.6 years) with cholesterol greater than 5.5 mmol/l were placed on a reduced-fat (less than 30% of calories from fat with a ratio of polyunsaturated to saturated fats of less than 1) diet for 3 months. If the cholesterol was between 5.5 and 7.5 mmol/l and total cholesterol divided by high-density lipoprotein cholesterol was greater than 4.5, the patients were randomly allocated either to the simvastatin (24 patients) or the placebo group (25 patients). Diet and placebo caused minor and insignificant falls in cholesterol and no change in triglycerides or lipids. Treatment with simvastatin reduced cholesterol levels from 6.85 to 4.75 mmol/l (P less than 0.001), triglycerides from 2.7 to 2.1 mmol/l (P less than 0.01), low-density lipoproteins from 4.6 to 2.6 mmol/l (P less than 0.001) and high-density lipoproteins rose from 1.09 to 1.18 mmol/l (P less than 0.01). Total cholesterol divided by high-density lipoprotein cholesterol fell from 6.3 to 4.0 (P less than 0.001). The drug was well tolerated and the side-effect profile did not differ from the placebo in clinical or biochemical events. The active drug was stopped in one patient (abdominal pain, dizziness, headache, tiredness) and in two patients taking the placebo (elevated creatine phosphokinase, cardiovascular collapse). Simvastatin effectively lowered total cholesterol and improved the lipoprotein profile. The dose required in most patients was 40 mg/day. Simvastatin may be an acceptable drug to improve the lipoprotein profile in order to determine whether this improves the prognosis in patients treated for hypertension.

Adult↗
PubMed1990

Prognosis of male patients with treated hypertension followed over 15 years.

1. Male patients aged 50-75 years on treatment for hypertension in 1973 have been followed for 15 years. 2. Overall mortality in the 271 patients was 63% and 41% died of vascular disease. 3. Coronary artery disease or sudden death occurred in 44% of the patients who died and was between 2 and 6 times more common than in the general population. 4. Treatment of hypertension has improved overall prognosis but mortality from coronary artery disease is more common than in the general population.

Aged↗
PubMed1990

Interaction of enalapril with sodium restriction, diuretics, and slow-channel calcium-blocking drugs.

While monotherapy sometimes controls blood pressure (BP), it is often essential to add a second drug for adequate control. This study examined in a factorial fashion the interaction of enalapril with some commonly used antihypertensive therapies. There were between 10 and 16 patients in each study, and the patients had responded in part to the two drugs used. Enalapril and sodium restriction lowered BP 12 +/- 3/11 +/- 2 and 4 +/- 2/3 +/- 1 mm Hg, respectively. The effects of the two therapies were additive, and there was no interaction. Enalapril and hydrochlorothiazide lowered BP 11 +/- 3/8 +/- 3 and 8 +/- 2/6 +/- 2 mm Hg, respectively. The effect of the two drugs together indicated a positive interaction of 4 +/- 2/3 +/- 1 mm Hg (p less than 0.05). Enalapril and nifedipine both lowered BP (10 +/- 2/8 +/- 1 and 11 +/- 3/8 +/- 1 mm Hg). The two drugs combined had a strongly positive interaction of 10 +/- 3/7 +/- 2 mm Hg (p less than 0.001). Enalapril can be used with the other therapeutic methods tested. If a converting enzyme inhibitor does not reduce BP adequately, it appears appropriate to add a thiazide diuretic or a slow-channel calcium-blocking drug. The mechanism of the positive interaction with diuretics probably reflects an effect on the renin-angiotensin system, but the explanation for the synergism with slow-channel calcium-blocking drugs is unclear.

Blood Pressure↗
PubMed1990

Neurologic, computed cranial tomographic, and magnetic resonance imaging abnormalities in patients with small-cell lung cancer: further follow-up of 6- to 13-year survivors.

To determine the subsequent evolution of neurologic, neuropsychologic, and intracranial anatomic findings in long-term survivors of small-cell cancer, we repeated an evaluation done 4 years previously in patients 6 to 13 years after treatment. Fifteen patients were reevaluated with a history and physical examination, mental status examination, neuropsychologic testing, computed cranial tomographic (CCT) scans, and magnetic resonance imaging (MRI). All but one was ambulatory and none were institutionalized. Thirteen of 15 had neurologic complaints, 10 of 15 had an abnormal neurologic examination, seven of 14 had an abnormal mental status examination, 12 of 14 had abnormal neuropsychologic testing, 12 of 15 had abnormal CCT scans, and seven of 15 had white-matter abnormalities on MRI scans. No dramatic decline in performance status, functional status, neurologic symptoms, or neurologic examination occurred in these patients with 4 years of additional follow-up. More patients showed a decline in mental status examinations and neuropsychologic testing than demonstrated improvement. Anatomic studies showed no dramatic changes in the CCT scans and MRI confirmed these findings. From these data we conclude that there is a slow decline in neuropsychologic function in some of the patients surviving more than 6 years from a diagnosis of small-cell lung cancer. The anatomic abnormalities documented by CCT scans and MRI are more frequent in patients with abnormal neuropsychologic function.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Effect of tube ovalling on pressure wave propagation speed.

For physiological and other flows it is often assumed that the pressure pulse wave speed is given by the classic Moens-Korteweg expression and this may be used, for example, to assist in the determination of in vivo blood vessel wall incremental Young's modulus. A number of physical factors affecting the value of this wave speed have been reviewed in the literature, but the effect of slight ovalling of the tube cross-section is rarely mentioned. The analysis for a tube of elliptic cross-section shows that even a very small degree of ovalling can cause quite substantial reductions in Young mode wave propagation velocities compared with the classic Moens-Korteweg expression. Bending-induced changes in cross-section shape with internal pressure increase the apparent elasticity of the tube wall. Experimental confirmation is provided by waterhammer wave speed measurements in a copper tube that has been ovalled by coiling. Even though the Young mode is not dominant in this case, as it would be for a physiological case, the measured wave speed is quite clearly less than the Moens-Korteweg theory and it can be shown that the small degree of measured tube ovality explains this.

Blood Flow Velocity↗
PubMed1990

Pharmacokinetics of carvedilol in older and younger patients.

Carvedilol, a combined beta- and alpha 1-blocking drug, was given to 8 young (age 39-47) and 21 old (age 64-79) patients with essential hypertension. Clinical and pharmacokinetic responses to 12.5, 25 and 50 mg were determined and compared. In both age groups, pharmacokinetic data were similar with all three doses of carvedilol. Peak blood levels were reached within 90 minutes and at 24 hours the trough blood level was less than 10% of the peak level. Carvedilol or its metabolite did not accumulate. Falls in systolic and diastolic BP were greater than 7 mmHg in 28 of the 29 patients. The falls in diastolic BP did not differ between groups but the older group had a greater fall in systolic BP. However, the systolic BP of the older group was higher and expressed as a percentage, the falls in BP did not differ. The time to peak fall in BP was about 4 hours and was always after the time to peak blood level. There was no correlation between blood level and BP fall. When the drug was administered 24 h after the previous dose, a further fall in BP was seen indicating a greater effect at peak drug levels. Side effects were few and, during the chronic study, there was no postural hypotension or postural hypotensive symptoms. On the study days, five patients developed postural hypotension with symptoms. These were not observed at other times and may have been due to decreased sympathetic outflow on the study days. Carvedilol lowered BP in order and younger patients. There were no significant effects of age on its pharmacokinetics. Carvedilol is an effective antihypertensive agent that can be used in people with essential hypertension in all age groups.

Adult↗
PubMed1990

A comparative study of zopiclone and triazolam in patients with insomnia.

Zopiclone, a cyclopyrrolone derivative, was compared with triazolam in a double-blind, randomized, parallel group study in general practice patients suffering from insomnia. Both drugs were found to be effective compared to baseline assessment in that they increased the number of hours of sleep, reduced the number of nocturnal wakenings and reduced the latency of falling asleep. In addition, both drugs improved patients' condition following awakening, with zopiclone showing slight superiority. In both treatment groups, there was a transient period of poor sleep after withdrawal of the drug, and one patient in each group withdrew from the study for this reason. There were no serious adverse reactions during the trial.

Adult↗
PubMed1990

The barrier function in extracapsular cataract surgery.

The distribution of fluorescein between the anterior chamber and the anterior vitreous was measured in two groups of patients after oral administration: group I, extracapsular cataract extraction (ECCE) patients with intact capsule and posterior chamber intraocular lens (PC IOL) (n = 12); group II, intracapsular cataract extraction (ICCE) patients with anterior chamber IOL (AC IOL) (n = 13). The fluorescein concentrations were measured by fluorophotometry and the penetration ratios were calculated. The penetration of fluorescein into the anterior vitreous was significantly less in the ECCE group (group I, penetration ratio = 2.03 +/- 1.00 X 10(-3) min-1; group II, penetration ratio = 5.99 +/- 4.89, X 10(-3) min-1, P less than 0.01). The authors concluded that in ECCE versus ICCE a significantly smaller proportion of fluorescein is found in the anterior vitreous relative to the aqueous after passage through the blood-aqueous barrier. This suggests a barrier to posterior movement of other molecules that may initially gain access to the eye in the anterior segment (e.g., prostaglandins).

Aged↗
PubMed1989

Imovane (zopiclone)

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Azabicyclo Compounds↗