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Biomedical subjects

T Mengden

Publications and source records attributed to T Mengden.

At least 55 records · Page 3Linked to original sources
PubMed1992

Oxidation of low density lipoprotein enhances its potential to increase intracellular free calcium concentration in vascular smooth muscle cells.

There have been suggestions that oxidation of low density lipoproteins (LDL) might increase their atherogenic potential. Because changes in intracellular free calcium concentration [Ca2+]i have been linked to atherogenesis, we compared the influence of oxidized LDL (Ox-LDL) and native LDL (N-LDL) on [Ca2+]i in vascular smooth muscle cells cultured from rat aortas. For determination of [Ca2+]i, fura-2 fluorescence was used. LDL was isolated by ultracentrifugation from the sera of human donors (n = 17). In N-LDL, oxidation was prevented by addition of antioxidants, whereas Ox-LDL was obtained by auto-oxidation. The extent of oxidation was assessed by measurement of thiobarbituric acid-reactive substances. Addition of Ox-LDL (20 micrograms protein/ml) to the vascular smooth muscle cells induced a mean increase of 129 +/- 13% in [Ca2+]i compared with 81 +/- 7% with N-LDL (p less than 0.01). Dose-response curves from 1 to 20 micrograms/ml (six experiments) confirmed this difference within the entire dose range. These results indicate that a more pronounced increase in [Ca2+]i induced by Ox-LDL might be one of the cellular mechanisms responsible for the higher atherogenic potential of Ox-LDL compared with N-LDL, as [Ca2+]i is an important second-messenger system involved in many atherogenic processes such as hypertrophy, cell migration, and cell damage.

Animals↗
PubMed1992

Betablocking drugs in essential hypertension: transdermal bupranolol compared with oral metoprolol.

In the present study the antihypertensive efficacy and tolerability of transdermal bupranolol (30 mg once-daily) was compared with oral metoprolol (100 mg once-daily). Blood pressure measurements were performed in the office, at home, and with ambulatory 24-h blood pressure devices. Systemic and local side-effects, as well as compliance and acceptance, were evaluated every two weeks. The treatment period lasted eight weeks. The results showed a significant decrease in blood pressure under the bupranolol transdermal therapeutic system in the office, at home, and with 24-h blood pressure measurements day- (08h00-20h00) and night-time (20h00-08h00). Under oral metoprolol there was a significant blood pressure decrease in the office, at home, and in the mean daytime values of the 24-h blood pressure measurements. The night-time values, however, demonstrated only a slight decrease in blood pressure, being significant only for diastolic values. Systemic side-effects were comparable in both groups. 69% of the patients had local side-effects at the patch side (erythema, papulous exanthema, pruritus). Six patients dropped out because of localized urticarial exanthema (five patients treated with transdermal bupranolol, one patient treated with oral metoprolol). In comparison to the oral form, twice as many patients had admitted to have been non-compliant with the patches (13 versus 7 patients). At the end of the study, 24 out of 32 patients preferred to be treated with capsules.

Administration, Cutaneous↗
PubMed1991

[Performing self-measurement of blood pressure: a patient survey].

In the present study the knowledge of 200 patients of our hypertension clinic about the technique of blood-pressure self-measurement was investigated using a questionnaire of 22 questions. 44-66% of the patients in different age groups measured their own blood-pressure, showing that self-measurement is commonly used, regardless of the age. 73% of the patients had bought a device on their own, but only 17% on the physician's advice. Possible causes for erroneous measurements were rarely known and underestimated by the patients. Due to lacking or insufficient instruction a relatively high percentage of the patients did not perform correct measurements. 45% did not measure the blood-pressure at the same time of day, 45% did not read systolic and diastolic pressures to the nearest 2 mmHg mark of the manometer scale, 59% did not count the pulse rate and 52% did not document the blood-pressure values. About half of the patients adjusted their medication on the ground of self-measured blood-pressure determinations. 45% of the elderly patients felt that their compliance had improved by self-measurement in contrast to 17% in the younger group. Given the increasing use of blood-pressure self-measurement we conclude that education of patients and physicians on possibilities and limitations of self-measurement as well as optimal training in the correct technique seem advisable.

Adult↗
PubMed1991

[How reliable is conventional blood pressure registration? Comparison with a semi-automatic device].

The aim of the present study was to determine observer error in measuring blood pressure by the conventional auscultatory method. Casual blood pressure was measured in two age-matched groups of normo- and hypertensive patients with a conventional mercury sphygmomanometer (n = 181) or a semiautomatic device (n = 176) by ten doctors of the university hospital. Although there were no significant differences in mean systolic or diastolic blood pressure values between the groups, the conventionally determined values showed a distinctively different pattern of distribution in comparison to the semiautomatically taken readings. With conventional readings a highly significant preference for terminal digit "0" (44%) and fewer systolic and diastolic values in the lower blood pressure range were observed. Furthermore there was a higher frequency of conventional readings ending in "8" than in "2". Terminal digit preference in the whole group was mainly due to the doctors, who did not measure blood pressure to the nearest 2 mmHg mark. Our results thus stress the importance of better and regular training in the correct technique of measuring blood pressure in order to reduce sources of observer bias.

Automation↗
PubMed1990

[Peroneal weakness].

The 22 year old male patient was admitted because of right sided peroneal nerve palsy two months after transient foot drop on the left side. Both pareses developed under a strict dietary regime leading to a weight loss of about 30 kg within 3 months. Slimmers' paralysis of peroneal nerve was diagnosed after exclusion of polyneuropathy or trauma as possible causes. Complete remission followed after a less restrictive diet.

Adult↗
PubMed1990

Low-density lipoprotein elevates intracellular calcium and pH in vascular smooth muscle cells and fibroblasts without mediation of LDL receptor.

Low-density lipoprotein (7 micrograms/ml) induced in the absence or in the presence of 7, 35, 70 micrograms/ml monoclonal antibodies against the specific Low-density lipoprotein receptor an elevation of intracellular Ca2+ from 105 to approximately 210 nM in vascular smooth muscle cells from rat aorta. Moreover, in both human cultured fibroblasts from normocholesterolemic individuals and from patients with familial hypercholesterolemia homozygote class 1, Low-density lipoprotein (7 micrograms/ml) induced a rise of free intracellular calcium and a biphasic change of intracellular pH. Low-density lipoprotein (1,7,15,30 micrograms/ml) had no significant influence on the phosphatidylinositol-turnover in vascular smooth muscle cells and fibroblasts. Since homozygote class 1 fibroblasts lack specific Low-density lipoprotein receptors, and as antibodies against this receptor did not attenuate the Low-density lipoprotein-induced elevation of cytosolic calcium and pH, we conclude that these intracellular changes are independent from the classical Low-density lipoprotein receptor.

Calcium↗
PubMed1990

[Skin spots, skin nodules, gangrene of the toes].

A 42-year-old man with multiple cutaneous neurofibromacules, café-au-lait and gangrene of toes was diagnosed having neurofibromatosis in 1976. An aortography performed because of severe hypertension had shown a coarctation and bilateral renal artery stenosis in 1982. Conservative antihypertensive therapy with an ACE-inhibitor, a vasodilatating agent and a diuretic resulted in gradual normalisation of blood pressure values. A recent follow-up revealed minimal progression of neurofibromatosis and hypertensive lesions documenting a benign course for over 13 years.

Adult↗
PubMed1990

Novel cellular activities for low density lipoprotein in vascular smooth muscle cells.

Hyperlipidemia and hypertension play important roles in the pathogenesis of atherosclerosis. To investigate the underlying intracellular mechanisms, we studied the effect of various concentrations of low density lipoprotein from normolipidemic subjects on concentrations of free intracellular calcium, intracellular pH, DNA synthesis, and vascular tone in vascular smooth muscle cells and rings from rat aortas. Low density lipoprotein in the range of 1-15 micrograms/ml induced a dose-dependent increase of concentration of free intracellular calcium and a biphasic change of the intracellular pH. Similar concentrations of low density lipoprotein led to an enhanced DNA synthesis. Furthermore, cumulative addition of 1-15 micrograms/ml low density lipoprotein produced a dose-dependent increase in contractile tension of thoracic aortic rings from rats. The maximal low density lipoprotein-induced contractile response was approximately 70% of that induced by 40 mM KCl. These findings indicate that low concentrations of low density lipoprotein occurring, for example, in the extravascular fluid might contribute to the pathogenesis of cardiovascular diseases by enhancing cell proliferation and vasoconstriction by changing intracellular calcium and intracellular pH.

Animals↗
PubMed1990

Casual versus ambulatory twenty-four-hour blood pressure measurement in a comparative study with bisoprolol or nitrendipine.

In a double-blind, placebo-controlled, randomly allocated study, the 24-h efficacy of a single morning dose of 10 mg of the beta-blocker bisoprolol (n = 17) versus 20 mg of the calcium channel antagonist nitrendipine (n = 19) was assessed using two different methods of blood pressure determination: (1) casual blood pressure determinations in the morning before the dose; and (2) ambulatory day-time (6 a.m. to 6 p.m.) and night-time (6 p.m. to 6 a.m.) blood pressure monitoring using a non-invasive automatic device (Spacelabs 90202). After 4 weeks both agents induced significant blood pressure reductions compared to the placebo period as assessed by both casual and ambulatory day-time readings, without significant differences in the blood pressure reductions induced by the two drugs (P less than 0.05). Ambulatory night-time values, however, showed a significant blood pressure reduction only for bisoprolol (from 138 +/- 16/84 +/- 12 to 129 +/- 15/77 +/- 11 mmHg); nitrendipine did not induce any significant systolic or diastolic blood pressure changes during this period (140 +/- 11/87 +/- 10 to 136 +/- 13/86 +/- 10 mmHg). Individual response rates were 47% for nitrendipine and 71% for bisoprolol. The incidence of side effects was comparable under both drugs. Our results indicate that bisoprolol was more effective over 24 h than nitrendipine. We also conclude that the value of casual blood pressure readings for the evaluation of therapeutic agents given once a day seems to be limited in comparison to 24-h ambulatory monitoring.

Adrenergic beta-Antagonists↗
PubMed1990

Ambulatory twenty-four-hour blood pressure measurements in pharmacological studies.

Until a few years ago, only casual blood pressure measurements were used in the diagnosis and treatment of arterial hypertension in clinical practice and in pharmacological studies. The development of portable lightweight devices for 24-h ambulatory blood pressure measurement has proved a substantial step towards reducing the potential pitfalls of casual blood pressure measurements. Ambulatory monitoring of blood pressure can improve pharmacological trials by excluding patients in whom blood pressure is elevated only in the clinic environment, and by increasing the accuracy and reproducibility of blood pressure values. Twenty-four-hour blood pressure measurement has great advantages for trials investigating the time-course of a particular drug, since the 24-h blood pressure rhythm is fully monitored. However, internationally accepted normal values for 24-h blood pressure measurements are required, and the interpretation of results obtained with this method needs to be standardized before the technique can be routinely used in antihypertensive drug trials.

Antihypertensive Agents↗
PubMed1990

Self-measured blood pressures at home and during consulting hours: are there any differences?

Home blood pressures are lower than casual blood pressures and this difference is probably due to physician-patient interaction in a clinical stress situation. In order to prove this assumption we compared the casual blood pressures of 127 subjects, measured by a physician and by the subjects themselves in the presence of the physician, with self-measured values obtained at home over a 7-day observation period. The casual pressures were higher than the home pressures (delta = 7.6/3.9 mmHg) regardless of whether they were taken by the physician or by the subjects themselves in the presence of the physician. The subjects' casual readings (132.9 +/- 17.5/87.6 +/- 12 mmHg) were slightly, but significantly, higher than those measured by the physician (131.9 +/- 18.4/86.3 +/- 12.6 mmHg) and both systolic and diastolic self-measured casual values were highly significantly correlated with the physician's readings (r = 0.92 and 0.91, respectively; P less than 0.01).

Adult↗
PubMed1990

Individualizing antihypertensive therapy with enalapril versus atenolol: the Zurich experience.

With the present increasing concern for compliance and quality or life during antihypertensive treatment, drug therapy tailored optimally for the individual patient is becoming increasingly important. The aim of the present double-blind crossover study was to analyse the individual as well as the group blood pressure response under enalapril and atenolol. Our results show that the group effects of these drugs did not differ significantly. However, individually, two-thirds of the responding patients showed a preference for either enalapril or atenolol. A response to one drug did not predict a comparable response to the other drug. We conclude that double-blind crossover studies are a possible way of individualizing antihypertensive treatment. However, no appropriate methodology or definitions of terms for these studies have yet been established.

Adult↗
PubMed1989

[ Self measurement of blood pressure. Equipment and comparison of equipment].

Precision is the primordial criterion for the evaluation of a blood pressure measuring device. While traditionally devices based on the auscultation technique have dominated semiautomatic devices have recently gained acceptance. The latter permit to reduce procedure-related errors. They are simpler to use and require less demanding instruction but are more expensive than stethoscopic devices.

Auscultation↗