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.

[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.

Effect of low-density lipoprotein on intracellular calcium, intracellular pH and DNA synthesis in cultured vascular smooth muscle cells

Low-density lipoprotein has proliferative effects on vascular smooth muscle cells and thus may play a role in the pathogenesis of atherosclerosis and hypertension. In order to investigate the underlying mechanisms, we studied the influence of low-density lipoprotein on intracellular free calcium, intracellular pH and the rate of DNA synthesis in cultured vascular smooth muscle cells of the rat aorta. The low-density lipoprotein (1-30 micrograms/ml) caused a dose-dependent increase in intracellular calcium and affected the intracellular pH accordingly. In addition, a marked low-density lipoprotein-induced increase in 3H-thymidine incorporation into DNA was observed. It is concluded that low-density lipoprotein, apart from its classical role as a cholesterol-transporting vehicle, enhances cellular processes leading to cell proliferation.

Cortisol-stimulated phosphoinositide metabolism in vascular smooth muscle cells: a role for glucocorticoids in blood pressure control?

Physiological concentrations of cortisol (0.02-5.0 micrograms/ml) stimulate the phosphoinositide breakdown in cultured smooth muscle cells from rat aorta. After a 15-min stimulation of the cells with various concentrations of cortisol, the inositol-1,4,5-triphosphate concentrations showed a dose-dependent increase. This phenomenon was qualitatively similar but quantitatively more sensitive in smooth muscle cells from spontaneously hypertensive rats (SHR) than in vascular smooth muscle cells from normotensive animals. When the antihormone RU 486 was added before the vascular smooth muscle cells were stimulated with cortisol, the inositol-1,4,5-triphosphate production was reduced to 50%.

[Why are blood pressure values higher in the doctor's office than at home?]

Blood pressure values measured by the patients at home are lower than those measured during medical consultation. To test whether the person measuring the blood pressure is responsible for this difference, the blood pressure of 127 patients was measured first by the doctor and then by the patients themselves during the consultation. There was a good agreement and no significant difference between the two measurements. Values taken at home were however significantly lower. Our results indicate, that difference between clinic and home blood pressure values does not depend on the person performing the measurement.

[Self measurement of blood pressure: patient education]

Many patients measure their blood pressure without any instruction due to the availability of modern measuring devices. Although the technique can be mastered by most of the patients, some sources of error have to be eliminated. The aim of such an instruction is to explain these sources of error to the patients and to give them opportunity to practise the self measurement under medical supervision. An instruction sheet is handed out as a pamphlet. The patients are also directed to keep a record of all measurements which is periodically controlled by the physician. It is also advisable to reexamine the measuring technique of the patient from time to time and to check the accuracy of the patients measuring device.

[The therapeutic significance of home blood pressure measurement]

Optimization of antihypertensive therapy during the initial dose titration as well as the long term follow-up of chronic therapy constitute the main therapeutic indications of blood pressure measurement at home. Furthermore home blood pressure measurements may be of value in patients with unsatisfactory blood pressure response in whom poor compliance is suspected. Finally patients may adjust their antihypertensive therapy according to the level of self-recorded blood pressure measurements.

[Diagnostic and prognostic aspects of home blood pressure measurement]

Up to now the diagnosis of hypertension has been based on a few casual blood pressure measurements in the physician's office according to WHO guidelines. Blood pressure measurements at home in the recent years have gained increasing popularity as a supplementary diagnostic tool. The establishment of an everyday blood pressure profile and exclusion of "white coat" hypertension are the main diagnostic indications. In borderline hypertension those patients with elevated home blood pressures can be identified. However world-wide epidemiologic studies are urgently needed to develop definitions of normal and pathological values for self-recorded blood pressure readings. From our experience diastolic home-recorded values higher than 90 mm Hg should be regarded as pathological.

[ 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.

[The treatment of essential hypertension in the hospital and in the office: is there a difference?]

An identical antihypertensive regimen with Metoprolol, a beta-blocking agent, was compared in two groups of patients with mild to moderate hypertension regarding effectiveness and side effects. 17 patients were treated by practitioners, 28 patients at the university clinic. The aim of the comparison was to appreciate possible effects of the clinical setting. With respect to the blood pressure reduction no difference was found between the two groups. Significant differences were noted however regarding side-effects. The practitioners reported fewer and less serious side-effects. This observation should caution about similar phenomena in similar studies and lead to modification of planning in future studies.

[The ambulatory patient history: an attempt at quality control]

At the medical outpatient clinic of the university of Zurich a sample of 200 records, 100 each from male and female patients was taken and analyzed to assess the quality of record-keeping. An average to acceptable quality was found regarding history, physical examination, diagnostic evaluation and treatment. Next to incomplete registration of anamnestic and clinical data deficiencies consisted in neglect of outdated or less important items of the check-list. Time-consuming or disagreeable procedures such as ophthalmoscopy or rectal examination could hardly be analyzed since the physician had often not indicated whether he had performed the procedure or found a normal state. Although evaluation of fitness to work was expected it was rarely documented and could not be analyzed. Check-lists for medical records should thus be adapted more frequently to meet changing demands. Periodic reviews of record-quality should serve to periodically inform doctors about deficiencies in their practice of patient work-up. Physicians should also be coerced to identify procedures that were not performed or which yielded normal findings.

[Hypertension and old age]

Pharmacotherapy of hypertension in the aged does not differ qualitatively but only quantitatively from that in use for younger patients. Adjusted, usually lower doses of diuretics, beta-blocking agents, ACE-inhibitors and calcium-channel blockers are the basic drugs. Individual aging processes and concomitant diseases determine the choice of drugs in the elderly (individualized therapy). All substances are initially prescribed at very low dose. The increasing infirmity of the aged often associated with tiredness, dyspnea and dizziness even without treatment requires careful instruction of the patient about effects and side effects of the prescribed medication. The old WHO-guidelines (systolic BP greater than or equal to 160, diastolic BP greater than or equal to 95 mm mercury) should be maintained for diagnosis and treatment of hypertension. However antihypertensive therapy in patients over 80 years of age and in those with marginally elevated diastolic or solely elevated systolic pressure is controversial today.

Evaluation of the therapeutic effect of transdermal beta-blocker therapy in patients with essential hypertension

Transdermal drug delivery has been applied to various agents in an effort to decrease the frequency of drug administration and improvement of the patients compliance. In the present study, it could be demonstrated that transdermal monotherapy (BIO TSD) with a beta-blocker (20 mg mepindolol) in patients with essential hypertension led to an effective 24 h blood pressure lowering effect within 1 week (160.1 +/- 6.1 mmHg/95.8 +/- 8.3 mmHg vs. 136.8 +/- 7.2 mmHg/84.3 +/- 5.0 mmHg; p less than 0.05). Also a reduction of excessive blood pressure peaks in the circadian blood pressure profiles was observed. Studies comparing transdermal with oral beta-blocker administration in hypertensive patients would further substantiate the value of this new therapeutic system as an antihypertensive treatment.

[Using drugs: experiences with a slide show program and patient questionnaires]

200 patients were surveyed by questionnaire while attending the medical outpatient service at the university hospital of Zürich. Questions related to a slide show on the usage of prescribed drugs presented at the same time in the attending room but also to general personal habits and attitudes regarding pharmacotherapy. Appreciation of the slide show was remarkable. This was substantiated by the observation that next to the physician media such as news papers, television and broadcast serve as source of information on drugs. Patient-compliance was in part related to lack of correct information. While older patients discontinued treatment because of side-effects, younger patients stopped drugs often because of improvement under therapy. In depth information could improve compliance in the latter population since particularly these individuals complained about insufficient instruction. The personal preference of "natural" over "chemical" drugs was surprisingly at variance with the admission of regular intake of prescription drugs--possibly a sign of an ultimately greater confidence in "chemical" drugs.

[Fish oil: clinical application possibilities]

Current interest in fish-oil stems in part from epidemiologic evidence gathered in eskimos. Due to a high proportion of fish in their diet eskimos have a low incidence in cardiovascular mortality. The active principle in fish-diet are n-3-fatty acids. These modulate prostaglandin and leukotriene metabolism. Numerous studies have been undertaken to demonstrate clinical usefulness. Current interests focus on lipid lowering, inhibition of hemostasis and antihypertensive actions. Furthermore antiinflammatory and immunologic effects as well as uses in oncology are discussed.

Vasoconstriction: a novel activity for low density lipoprotein

Low density lipoprotein plays an important role in the pathogenesis of atherosclerosis. Cumulative addition of 1-30 micrograms/ml of LDL from normolipidemic subjects produced a dose-dependent increase in contractile tension of thoracic aortic rings from rats. The maximal LDL-induced contractile response was approximately 30% of that induced by 1 microM norepinephrine. Similar concentrations of LDL induced a dose-dependent transient increase of the concentration of intracellular free calcium, and a biphasic change of the intracellular pH in cultured rat vascular smooth muscle cells. We conclude that low density lipoprotein occurring for example in the extravascular fluid can mediate vasoconstriction by changes in cytosolic calcium and intracellular pH.

Fish oil affects phosphoinositide turnover and thromboxane A metabolism in cultured vascular muscle cells

Fish oil has been reported as having beneficial effects on cardiovascular diseases. Elevated serum lipoproteins, prostaglandins and intracellular free calcium concentrations [( Ca2+]i) of the vasculature and thus the phosphoinositide (PI) turnover may be involved in the pathogenesis of these disorders. Therefore, the effect of fish oil on the potency of both low-density lipoprotein (LDL) and angiotensin II (AII) to stimulate the PI turnover in cultured rat vascular smooth muscle cells (VSMC) has been studied. Furthermore, a possible link between PI turnover activity and thromboxane A2 (TXA2) metabolism in these cells has been investigated. In VSMC cultured for up to 7 weeks with either fish oil or n-3 eicosapentaenoic acid (EPA) a decrease to 5-48% of the LDL-induced inositol trisphosphate (IP3) formation (= 100%) was found. A similar range of decreased IP3 synthesis was observed, when AII was used instead of LDL. Both LDL- and AII-stimulated TXA2 synthesis was suppressed concomitantly within the range 34-60%. Blockade of VSMC TXA2 biosynthesis with either indomethacin or TXA2 synthetase blocker (SQ-80338) inhibited LDL-induced formation of IP3 in a dose-dependent manner. Similar results were obtained, when TXA2 receptor coupling antagonists (SQ-27427 or BM-13177) were used. However, blockers of TXA2 synthesis and of TXA2 receptor binding failed to affect AII-induced formation of IP3.

[Acute facial swelling, pruritus]

This patient developed facial edema with impressive swelling of the inferior lip within a few hours. He had experienced several episodes with transient, itching swelling at diverse sites over the past six months. This history and the rapid disappearance of symptoms after intravenous corticoids were suggestive of Quincke's edema. Since testing for possible causes remained unsuccessful idiopathic Quincke's edema was diagnosed.

Blood pressure self-measurement in normotensive and hypertensive patients

In this study casual blood pressure was compared with home blood pressure measurement in 41 normotensive, 39 hypertensive and 21 borderline hypertensive subjects. The average casual readings for the whole group were 8.6 mmHg higher for systolic and 4.0 mmHg higher for diastolic pressures than self-determined values. Casual and home-registered blood pressures showed a highly significant relationship (P less than 0.001) for both systolic and diastolic blood pressure readings. In the distribution of self-measured diastolic blood pressure readings, normotensive subjects rarely (5%) showed values higher than 90 mmHg, whereas hypertensive subjects had a relatively high percentage of diastolic readings above that level (55%). The results confirm previous reports of lower self-determined than casual blood pressure values. However, the high correlation between these two methods of blood pressure measurement indicates that in general there is a quantitative rather than a qualitative difference between casual and self-registered blood pressures. Finally, self-registered diastolic values exceeding 90 mmHg may be interpreted as hypertensive.

Effect of fish oil on blood pressure and serum lipids in hypertension and hyperlipidaemia

We studied the antihypertensive and hypolipidaemic effects of fish oil containing eico-sapentaenoic acid and docosahexaenoic acid in a capsule preparation in patients with mild to moderate essential hypertension and in patients with hypercholesterolaemia. In addition, we used two independent procedures to analyse changes in blood pressure, casual and self-recorded blood pressure measurements. A very moderate blood pressure lowering effect of fish oil was confirmed in this study, and a slight antihyperlipidaemic effect in plasma triglycerides was demonstrated. During the fish oil treatment, casual blood pressure values were consistently lower than self-recorded values. It is assumed that this was an observer error due to knowledge of the treatment.

Ca2+-channel blockers inhibit the action of recombinant platelet-derived growth factor in vascular smooth muscle cells

Human platelet-derived growth factor (PDGF) is mainly composed of two polypeptide chains (PDGF-AB). All three possible dimeric forms of PDGF--i.e., PDGF-AA, PDGF-BB and PDGF-AB--exist in nature. We have used two recombinant PDGF homodimers to determine the roles of each isoform in the activation of phosphatidylinositol turnover in vascular smooth muscle cells (VSMC) isolated from rat thoracic aorta, their mitogenic effect on VSMC, and their vasoconstrictor effect on intact strips of aortic vascular tissue. Three Ca2+-channel blockers, nifedipine, verapamil, and diltiazem, were used as antagonists for investigating the PDGF-dependent changes mediated by the homodimers. PDGF-BB had a greater efficacy than PDGF-AA on inositol 1,4,5-trisphosphate release, on the formation of diacylglycerol, and on Ca2+ mobilization, which was also associated with vasoconstrictor activity and effective mitogenicity. PDGF-AA, on the other hand, was more potent than PDGF-BB in stimulating protein kinase C. In all instances, the activation of the phosphatidylinositol turnover by the two homodimers was inhibited by the Ca2+-channel blockers.

[Intestinal drug smuggling--a new diagnostic and therapeutic problem]

Since spring 1985 81 persons were examined because of suspected intestinal drug-smuggling (body-packing). 46 patients (57%) had drug-packages in the gastro-intestinal tract, in 35 persons (43%) the suspicion was not confirmed. 26 patients had swallowed the drugs (mostly cocaine) whereas in 20 cases drugs were found in the rectum (mostly heroine). Most important for diagnosis was abdominal x-ray whereas in our hands abdominal sonography was unreliable. When body-packing is diagnosed, observation and mild laxative in conjunction with sufficient beverages are recommended. Serious complications in our series comprised one patient with mechanical ileus and another with heroine-poisoning after rupture of a package.