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Biomedical subjects

B Bergdahl

Publications and source records attributed to B Bergdahl.

At least 19 recordsLinked to original sources
PubMed1995

Trials of lipid-lowering therapy in secondary prevention of coronary heart disease.

The Scandinavian Simvastatin Survival Study showed that a 35% decrease in LDL-cholesterol was accompanied by a 42% reduction in coronary mortality. Even if the period of time is longer than 1 year for the divergence of survival curves in the simvastatin and placebo groups there are reasons to believe that the beneficial effect of lipid lowering is rapid. The effect may be mediated by stabilization of lipid-rich coronary lesions or by effects on endothelium. Lipid-lowering studies in the acute stage of coronary heart disease are suggested.

Anticholesteremic Agents↗
PubMed1993

An automatic computerized bipolar coagulator for dermatologic surgery.

BACKGROUND: The problem with all bipolar diathermy equipment is the adherence of the tissue to the prongs of the forceps. OBJECTIVE AND METHODS: We describe a new computerized bipolar coagulator (Coa-Comp/M) with electronic feedback of the tissue impedance that automatically starts and shuts off coagulation thus preventing overheating, undue tissue damage and sticking of the forceps. The fully automation implies that no footswitch or handcontrol is necessary. The coagulator was tested during 2 years in advanced dermatologic surgery. RESULTS: A log memory recorded the number of coagulations according to effect and coagulation time. A power setting of 16W was appropriate for effective coagulation of most vessels; 99% of the coagulations were faster than 1.3 seconds necessitating automatic control for preventing sticking and charring. CONCLUSIONS: The automatic bipolar coagulator saves time and avoids sticking of the forceps. It is a useful tool in dermatologic surgery demanding repeated coagulations for hemostasis.

Dermatology↗
PubMed1991

Studies on coagulation and the development of an automatic computerized bipolar coagulator. Technical note.

A new computerized bipolar coagulator is described in which tissue heating is switched off automatically when adequate vessel occlusion has been achieved, thus preventing overheating, undue tissue damage, cutting, and sticking of the forceps. Experiments with radiofrequency (rf) heating of albumin or arteries revealed an impedance minimum at the moment of coagulation. The attainment of this impedance minimum is transmitted electronically via a microprocessor to the coagulator, which automatically shuts off the rf energy supply. In experiments, adequate artery strength and avoidance of the drawbacks of conventional coagulation methods were achieved when rf heating was shut off soon after the impedance minimum was reached. Neither irrigation for cooling nor cleaning of the forceps tips was necessary. Electronic feedback through the same cables as used for coagulation enabled the use of conventional bipolar cables and forceps. The bipolar coagulator described can also be used for conventional bipolar coagulation under visual control. The microcomputer enables: 1) automatic coagulation cycles that start when tissue is picked up in the forceps and stop automatically on completion of the seal; 2) the change of power setting from a pedal and activation of automatic cycles by the pedal as described above or surgeon-controlled coagulation, which facilitates the use of alternative debridement with inactive forceps; 3) cable testing; and 4) negligible disturbance of the intraoperative monitoring equipment.

Animals↗
PubMed1988

Decreased plasma levels of cyclic GMP in patients with chest pain and angiographically normal coronary arteries.

Plasma levels of cyclic nucleotides were determined by radioimmunoassay in patients with (1) angina-like chest pain and normal coronary arteries (suspected spasm angina), (2) exercise-induced angina, and (3) heart diseases other than angina pectoris, as well as in (4) normal subjects. The concentration of cyclic GMP in plasma was significantly lower (by at least three-fold) in patients with suspected spasm angina, as compared with the other groups. No statistically significant difference in the plasma levels of cAMP was observed between the different patient groups. The low cGMP levels in plasma from patients with angina-like chest pain and normal coronary arteries might be an indication of a defect in the vasculature, making it more sensitive to contractile stimuli.

Adult↗
PubMed1988

Once daily dosing of enalapril in congestive heart failure.

Enalapril 40 mg or tolerated dose was given once daily to 21 patients with congestive heart failure (CHF), NYHA class III, in addition to treatment with digoxin and/or diuretics. After an 8-week open period, 19 patients were randomized to continue enalapril or to receive a placebo in a double-blind manner. After the first enalapril dose of 10 mg, maximal reduction of blood pressure (BP) occurred after 4 hours (mean 34/17 mmHg; p less than 0.001). No further reduction was found after higher doses. After the open period significant improvement was shown as judged by NYHA class (p less than 0.01), stroke volume (p less than 0.05), maximal working capacity (p less than 0.05), heart volume (p less than 0.01) and maximum rate pressure product (RPPmax) (p less than 0.001). Urinary aldosterone markedly decreased (p less than 0.01), whereas serum potassium and serum creatinine slightly increased (p less than 0.05). At the end of the blind period enalapril was superior to placebo concerning NYHA class (p less than 0.01), heart volume (p less than 0.05) and RPPmax (p less than 0.05). Other parameters, including aldosterone in urine, did not differ between the groups. Carry-over effects may have diminished the differences between enalapril and placebo. Diarrhoea (n = 5) and hypotension (n = 5) were the most common side-effects. Overall, enalapril was well tolerated and seems to be useful in single daily doses in the treatment of CHF.

Adult↗
PubMed1986

The relaxant effect of glyceryltrinitrate on isolated human peripheral vein and its relation to cyclic GMP metabolism.

The relaxant effect of glyceryltrinitrate (GTN) on human vena saphena magna was studied in vitro. Vessels contracted by serotonin (0.25 microM) and phenylephrine (0.1 mM) were relaxed to the same extent (EC50 = 10 microM) by GTN, whereas in 100 mM K+-depolarized vessels the relaxation was significantly lower. The relaxant effect produced by GTN was preceded by an elevation of cyclic guanosine-3',5'-monophosphate (cGMP). For 0.1 mM GTN there was a 3-fold increase in cGMP after 3 min. A correlation between relaxation and increase in cGMP was established. When GTN was combined with dipyridamole (5 microM) the relaxant effect of GTN was significantly greater (EC50 = 0.1 microM). Phosphodiesterase inhibition, as a possible mechanism behind the observed better relaxation for the combination (GTN+dipyridamole), is briefly discussed. In conclusion, the relaxant effect of GTN on isolated human vena saphena magna seems to be dependent on the contractile stimuli used, increased by the addition of DIP and to be mediated via cGMP.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1984

Increased metabolism to dihydrodigoxin after intake of a microencapsulated formulation of digoxin.

A capsule preparation containing small, enteric-coated granules of digoxin was developed to prevent acid hydrolysis of the drug in the stomach and to diminish the variation in plasma glycoside concentration during the intervals between doses. The absorption and metabolism of tritiated digoxin after a single oral loading dose of this formulation (Formulation C) were compared to those after ingestion of a digoxin solution (Formulation S) by 8 healthy men. Drug concentrations were measured by radioimmunoassay (RIA) and liquid chromatography (LC). The percentage of the digoxin dose excreted in the urine during 72 h, as measured by RIA, was significantly lower after the capsule (20.5 +/- 2.0% vs 36.2 +/- 3.0% after S, mean +/- SEM) but total urinary radioactivity after the two treatments was similar (C 35.3 +/- 5.2 and S 41.2 +/- 2.6%; p greater than 0.05). The discrepancy was mainly due to significantly greater excretion of dihydrodigoxin after the capsule (m 12.8%, range 0-28.6% of the dose) than after the digoxin solution (m 5.4%, range 0-14.5%). Dihydrodigoxin was not measured by the RIA. The recovery of hydrolysis metabolites (LC) was greater during the first 24 h after S (2.3 +/- 0.6% vs 0.9 +/- 0.3% after C; p less than 0.05). The peak plasma concentration of digoxin (RIA) was significantly reduced and delayed after intake of C (2.5 +/- 0.4 nmol/l at 3.8 +/- 0.3 h vs. 8.3 +/- 0.8 nmol/l at 0.9 +/- 0.1 h after S), and so was the shortening of electromechanical systole at 1.5 h, 2.5 h, and 3 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Automatically controlled bipolar electrocoagulation--"COA-COMP".

Modern bipolar electrocoagulation has certain limitations, especially regarding the regulation of the short coagulation course. Studies on the electrical parameters of tissues during heating led to the conclusion that impedance changes in a typical and reproducible way. Furthermore, the impedance value proved to be close to minimal at the moment of coagulation. Laboratory tests were performed to correlate the pressure strength of the sealed artery to the impedance change. The tests proved that strong seals were achieved when the coagulation was interrupted soon after minimum impedance. Good seals were also achieved with later interruption of the heating but the well-known phenomena of sticking of the forceps to tissues and charging of the tips with charred tissue became more prominent. Further electrocoagulation gives carbonisation, fulguration and risk of new haemorrhage. Based on these results, micro-computerized equipment was built which cut off the coagulation soon after minimum impedance, i.e. when good strength without sticking was achieved. This equipment was tested clinically and the trials showed that the method is practical and most reliable. The microcomputer also allows automatic start of the coagulation as needed during opening or closing of wounds, as well as providing a built-in test of the equipment. This equipment saves time and labour and increases safety.

Electrocoagulation↗
PubMed1984

Urinary excretion of digoxin and its metabolites in hyperacidic patients and in patients during coronary care.

The hydrolytic cleavage of digoxin was studied after single oral doses of tritiated glycoside to four patients with gastric hyperacidity (GH-group) and to six patients during coronary care (CCU-group). Drug analysis was performed with a high-pressure liquid chromatographic method. Results in the two groups did not differ and were similar to results in a previous study in healthy volunteers. On the average 22% of the radioactivity was recovered in 24-h urine specimen. Of this 24.8 +/- 8.5% (GH-group, mean +/- SEM) and 19.3 +/- 6.6% (CCU-group) were cleavage products and unidentified, polar metabolites in equal amounts. This indicates that hydrolysis of digoxin is on average limited even in patients at risk for such metabolic cleavage.

Adult↗
PubMed1983

Fasting and postprandial absorption of digoxin from a microencapsulated formulation.

The absorption of digoxin from a capsule preparation containing a large number of small, enteric-coated granules of the glycoside (Preparation CR) was compared in 10 volunteers with that from a rapidly dissolving tablet (Preparation L). Plasma and urine digoxin concentrations were measured by radioimmunoassay. In the fasting state, after a loading dose of digoxin (0.76 mg), peak plasma concentrations were significantly (p less than 0.001) lower after CR (2.0 +/- 0.5 nmol/l, mean +/- SD) than L (4.7 +/- 1.1 nmol/l). Peak concentrations after CR were significantly (p less than 0.001) delayed compared to L (3.3 +/- 0.6 h vs 1.1 +/- 0.4 h). Also, postprandial peak plasma concentrations at steady state, were significantly (p less than 0.01) lower after CR (1.0 +/- 0.3 nmol/l) than L (2.7 +/- 0.5 nmol/l), and the peak concentrations occurred later (3.9 +/- 1.7 h vs 1.4 +/- 0.9 h). The area under the plasma concentration-time curves was smaller (p less than 0.01) for CR (17.7 +/- 5.9 nmol X 1(-1) X h) than for L (22.4 +/- 4.1 nmol X 1(-1) X h), and so was the amount of drug excreted in urine (174 +/- 25 micrograms vs 190 +/- 31 micrograms; p less than 0.005). Thus, the absorption rate of digoxin from the enteric-coated formulation was markedly reduced but at the cost of a variable reduction in the amount absorbed.

Adult↗
PubMed1983

Reproducibility of standard preparation in digoxin radioimmunoassay in plasma and serum.

We studied the reproducibility of standard preparations in digoxin radioimmunoassay in a randomized trial using serum and plasma as matrices. The errors expressed relative to the observed counts per minute (cpm) attributable to each of the procedures involved in the preparation of standards were as follows: preparation of stock solutions and dilutions, 1.3%; addition of diluted solutions to the medium, 1.2%; and residual error due to the assay procedure, 3.7%. No error caused by mixing, portioning, and storage was detected. Heparinized plasma gave lower cpm values than serum at 4.0 ng/ml (p less than 0.01), an effect that would give over- or underestimations by about 5% at that level, depending on the medium used. This suggests that standard and sample matrices should be similar. Our procedure for preparing the standards seems to be reasonably reliable; this is necessary for satisfactory monitoring of patients on digitalis therapy.

Digoxin↗
PubMed1982

Metabolism of digoxin and absorption site.

After oral intake of enteric-coated granules containing [3H]-digoxin extensive metabolism was observed. Maximum 66% of the 24 h urinary excretion was identified as [3H]-dihydrodigoxin, using high performance liquid chromatography for the analysis. It is suggested that metabolism of digoxin may depend on the absorption site.

Biotransformation↗
PubMed1980

Absorption of digoxin from a new microencapsulated formulation.

The absorption of digoxin from two capsule preparations containing a large number of small, enteric-coated granules of the glycoside (0.38 mg) was compared with that of the same amount from ultrarapidly dissolving commercial tablets. Eight volunteers were studied during steady state conditions. Digoxin concentrations in plasma and urine were measured by radioimmunoassay. Peak plasma concentrations of digoxin were significantly (p < 0.01) delayed after taking the capsules (2.6 +/- 1 h and 2.6 +/- 0.9 h, mean +/- SD) as compared to the tablets (1.3 +/- 0.7 h). The peak concentrations produced by the capsules were 3.1 +/- 1.0 and 2.6 +/- 1.1 nmol/l; only the latter was significantly (p less than 0.05) lower than after the tablets (3.4 +/- 1.0 nmol/l). Areas under the plasma concentration-time curves during a 24 h dosage interval were similar for the three preparations, and so was the 24 h urinary excretion of digoxin, which averaged 60-63% of the daily dose. Thus, this particular enteric coating of digoxin delayed absorption without reducing the amount absorbed.

Adult↗
PubMed1980

An evaluation method providing confidence intervals applied to radioimmunoassay.

A method for evaluation of radioimmunoassay results is described. The order of the single tubes in each assay run is randomized. A polynomial is fitted to untransformed data (y = counts per minute; x = concentration of curve.A confidence interval is calculated for each sample, taking into account the variance of the standard curve and that of the actual duplicate assay jointly.

Humans↗