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Biomedical subjects

I Hjermann

Publications and source records attributed to I Hjermann.

At least 19 recordsLinked to original sources
PubMed1992

Long-term effect of lovastatin alone and in combination with cholestyramine on lipoprotein (a) level in familial hypercholesterolemic subjects.

We have determined the effect of lovastatin alone or in combination with cholestyramine on lipoprotein (a) [Lp(a)] levels in 59 heterozygotes for familial hypercholesterolemia (FH) treated for 33.8 (+/- 6.1) months. The median pretrial Lp(a) value was 10.2 mg/100 ml, which is twice the median value in healthy people examined at the Institute of Medical Genetics, University of Oslo. The median Lp(a) level was insignificantly reduced by 10.3% during the first 20 weeks when the subjects were on a standardized medication of increasing doses of lovastatin and cholestyramine. The first 20 weeks were followed by usual care treatment period, and a further decrease in Lp(a) level to 16.2% (P = 0.0012) was observed at the end of the study. Comparison between the 20 subjects on lovastatin monotherapy and the 31 subjects on the combined therapy of lovastatin and cholestyramine, revealed that the subjects on monotherapy had a median reduction of 20.1%, and the subjects on the combined therapy had a reduction of 15.4%. Thus, it appears that the reduction in Lp(a) level could be ascribed to lovastatin alone.

Adolescent↗
PubMed1992

The influence of dietary change on hemostatic risk variables.

In the 1970s in the Diet-Antismoking Trial, of the Oslo Study, colleagues and I found that the majority of high-risk men with elevated serum cholesterol and elevated triglyceride concentrations had impaired fibrinolytic capacity. Later on, both our group and others found a similar negative correlation between serum triglyceride levels and fibrinolytic capacity. Furthermore, in a prospective study of dietary intervention in individuals with both elevated cholesterol and triglyceride levels, we found that dietary lowering of serum triglyceride levels was significantly and positively correlated with an improvement in fibrinolytic capacity. In another study, we made the same observation for the coagulation factor VII-phospholipid complex: the more the triglycerides were reduced by diet, the greater was the change in factor VII complex. This correlation was highly significant and independent of changes in serum cholesterol. Platelet function is also influenced by dietary habits, but except for the effects of a fish oil-enriched diet, few data are available about the dietary effects on platelet function. It seems, however, that in individuals with elevated lipid levels and elevated blood pressure, increased platelet reactivity is a highly prevalent finding. Many of the hemostatic risk variables are associated with the so-called "metabolic risk syndrome" characterized by an increase in serum insulin level, together with increased relative body weight, mild hypertension, hyperlipidemia, and physical inactivity. This syndrome can often be influenced favorably by life-style changes. A controlled study with interventions in diet and activity level has just been started by our group.

Adult↗
PubMed1992

The metabolic cardiovascular syndrome: syndrome X, Reaven's syndrome, insulin resistance syndrome, atherothrombogenic syndrome.

A short review of the metabolic cardiovascular risk syndrome (MCVS) is given. Traditionally, cardiovascular risk has been associated with three so-called "main" risk factors; hypercholesterolemia, hypertension, and smoking. In addition, the association between diabetes and cardiovascular disease has been known for many years in clinical medicine. Primarily, these risk factors have been regarded separately as independent factors, although epidemiological studies showed intercorrelations between them. However, it is now well accepted that relatively few at-risk individuals have only one risk factor, and in many cases a whole "symphony" of factors play together to create what we might call an individuals' risk profile. As an example, very often essential hypertension has been regarded as a disease in itself, which can be successfully treated just by lowering the blood pressure by drugs. When such a strategy obviously failed, the association of elevated blood pressure with dyslipoproteinemia and impaired glucose tolerance attracted more attention, particularly when it was realized that many antihypertensive drugs affected risk in MCVS in a possible negative way. The most important etiologic factor of MCVS is (besides genetics) an excessive caloric intake compared to what the individual spends in physical activity. In the clinical setting, the most important findings of MCVS are central obesity, dyslipoproteinemia with low high-density lipoprotein (HDL) cholesterol, hypertension, reduced insulin sensitivity in peripheral tissues, and increased thrombogenicity. The reduced insulin sensitivity leads to a compensatory increase in beta-cell insulin production, and thereby hyperinsulinemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗
PubMed1992

StyI polymorphism in an enhancer region of the second intron of the apolipoprotein B gene in hyper- and hypocholesterolemic subjects.

The regulation of the human apolipoprotein (apo) B gene that plays a crucial role in lipid metabolism is apparently very complex, with multiple cis- and trans-acting regulatory factors. One of these factors is an enhancer region in the second intron. In this region a point mutation at position + 722 has been found that is detectable by the restriction enzyme StyI. The report of Levy-Wilson et al. (1991) could suggest that the mutant allele (abolished StyI site) is associated with hypocholesterolemia. To investigate further the possible effect of this mutation on plasma cholesterol levels, we have compared the frequency of the mutant allele between 206 hypercholesterolemic Norwegian or Czech subjects on one hand, and 165 hypocholesterolemic Norwegian or Czech subjects on the other hand. No significant difference in frequency was found between the hypercholesterolemic and the hypocholesterolemic groups. This finding indicates either that the mutation at position + 722 does not affect the enhancer activity or that this in vitro enhancer activity is of little or no clinical significance. One of the Norwegian hypercholesterolemic subjects who was of Czech descent possessed the apoB 3500 mutation that leads to defective binding of low density lipoprotein (LDL) to the LDL receptors. Haplotype analysis of the apoB gene in her family showed that the mutation-bearing allele was identical to that reported in other countries, indicating a common gene source.

Adult↗
PubMed1991

[Hypertension as a part of metabolic cardiovascular syndrome].

Hypertension is only one of several cardiovascular risk factors that tend to cluster. Hypertension is associated with glucose intolerance, hyperinsulinemia, decreased HDL-cholesterol, high triglycerides and decreased fibrinolytic activity. One possible link is insulin resistance, which also links hypertension to obesity and diabetes mellitus type II. The authors review the literature and discuss clinical and therapeutic implications in the treatment of hypertension. Since the hypertensive patient may have an unfavourable cardiovascular risk profile, a non-pharmacological approach is essential in the treatment. Furthermore, if antihypertensive agents have to be used, metabolic side effects should be monitored closely, since they may reduce the beneficial effects of the blood pressure reduction on the cardiovascular risk profile.

Antihypertensive Agents↗
PubMed1989

[Dietary advice in hyperlipidemia. A challenge for the health care service].

We propose practical dietary advice for patients with hyperlipidemias, based on data obtained from new results in epidemiology, clinical trials and laboratory experiments. We suggest a schedule for obtaining reliable data on dietary habits, to be used as a basis for advice to the individual patient. If the dietary fat intake can be reduced from about 40% to 25% of the total energy it is possible to achieve an average reduction in serum cholesterol of 10-20%. It is very important that doctors and other health personnel become involved in providing dietary advice in connection with treatment and prevention of coronary heart disease.

Coronary Disease↗
PubMed1989

[Hypercholesterolemia. Use of laboratory analysis].

The article summarizes the use of laboratory analysis as described in the recently published Norwegian program for diagnosis and treatment of hypercholesterolemia in adults. Serum cholesterol is used both to diagnose hypercholesterolemia and to monitor the effect of treatment. Serum triglycerides should be measured when hypercholesterolemia has been found and dietetic treatment is considered. High density lipoprotein (HDL) cholesterol should be measured when dietetic treatment has not reduced hypercholesterolemia sufficiently and drug treatment is considered. We do not at present recommend measurement of apolipoproteins and factors within coagulation/fibrinolysis, but such measurements might be of importance in the near future. Blood cholesterol exhibits large biological variations, which makes retesting necessary before hypercholesterolemia is diagnosed. Analytical variation is usually less than biological variation, but requires use of quality control materials. This control is equally important for small dry chemistry analyzers as for wet chemistry analyzers.

Blood Chemical Analysis↗
PubMed1989

Effect of dopamine and dopamine-antagonist infusion on blood platelet count, size and release reaction in hypertensive and normotensive subjects.

To examine the effect of dopamine on in vivo platelet function and a possible platelet contribution to the clearance of dopamine we measured platelet count, platelet size and plasma concentration of the platelet specific protein beta-thromboglobulin (BTG) in groups of 40 year old untreated hypertensive and normotensive men. One hypertensive (n = 10) and one normotensive (n = 10) group received dopamine infusion at doses from 0.5 to 2.0 micrograms/kg/min which increased plasma dopamine 100-fold from baseline. Two other groups of hypertensive (n = 10) and normotensive (n = 11) subjects received 10 mg of the dopamine antagonist metoclopramide intravenously, upon which serum prolactin concentration increased 10-fold. No significant effect on platelet function in any group was observed during these interventions. Platelet phenol-sulphotransferase may contribute to dopamine conjugation. However, the selected platelet parameters correlated only weakly with dopamine kinetics during the infusion. Neither dopamine nor a dopamine antagonist altered the selected platelet parameters, nor did these parameters influence the clearance of dopamine during a short-lasting pharmacological infusion.

Blood Platelets↗
PubMed1988

Effects of lovastatin alone and in combination with cholestyramine on serum lipids and apolipoproteins in heterozygotes for familial hypercholesterolemia.

We have studied the effect of lovastatin, an inhibitor of the rate-limiting enzyme in cholesterol biosynthesis (3-hydroxy-3-methylglutaryl coenzyme A reductase), alone and in combination with the bile acid sequestrant cholestyramine on lipid parameters in 30 heterozygous patients with familial hypercholesterolemia (FH) during a 20-week open trial. Lovastatin 40 mg bid (twice daily) decreased significantly total serum cholesterol, low density lipoprotein (LDL)-cholesterol, triglycerides and apolipoprotein B by 36%, 45%, 29% and 11%, respectively, while high density lipoprotein (HDL)-cholesterol and apolipoprotein A-I were increased significantly by 16% and 37%, respectively. These data are consistent with a reduction in both the number of LDL particles and in their cholesterol content. Addition of cholestyramine 4 g bid caused a significant further decrease in total serum cholesterol and LDL-cholesterol to a total of 43% and 61%, respectively. The addition of 4 g bid or 8 g bid of cholestyramine caused only minor changes in the other lipid parameters. No effect was found by these drugs on Lp(a) lipoprotein level. We conclude that lovastatin alone or in combination with a small dose of cholestyramine normalizes the lipid profile in most FH heterozygotes.

Adult↗
PubMed1988

Decreased serum phosphate in essential hypertension. Related to increased sympathetic tone.

Forty-year old men with untreated mild essential hypertension (n = 35) had decreased serum phosphate (P less than 0.001) concomitant with elevated resting plasma epinephrine (P less than 0.05) and heart rate (P less than 0.001) compared with age-matched, normotensive control men (n = 44). Blood pressure correlated negatively with serum phosphate (P less than 0.001) and positively with plasma epinephrine (P less than 0.01) and heart rate (P less than 0.01). Serum phosphate was significantly lowered during infusion of epinephrine, increasing arterial plasma epinephrine within the lower pathophysiological range corresponding to arousal reactions. Serum concentrations of immunoreactive parathyroid hormone were unchanged. Thus, hypophosphatemia in patients with mild essential hypertension appears to be inversely related to sympathetic adrenal tone and may be caused by increased plasma epinephrine within pathophysiologic arterial concentrations.

Adult↗
PubMed1988

Correlates of blood pressure change in middle-aged male mild hypertensives: results from the untreated control group in the Oslo hypertension trial. The Oslo Study.

The never-treated control group in the Oslo Study hypertension trial of middle-aged men 40-49 years old at entry (n = 379) was studied with respect to five-year change in blood pressure and its correlates. The study began in 1972 and ended in 1979, and each patient was followed for five years. Both baseline and rate of change of correlates were analyzed as independent variables versus rate of change in blood pressure as the dependent variable. Rate of change in serum triglycerides were found to be the strongest correlate of rate of change in blood pressure in this population of healthy mild hypertensives. In addition, rate of change in serum cholesterol and body weight made significant contributions in some analyses, but to a lower degree than did rate of change in triglycerides. The model predicts a substantial decrease in blood pressure if lipids and body weight are reduced. Rate of change in sodium, uric acid, and chloride concentrations were also associated with blood pressure change, but total degree of explanation of all explaining variables only accounted for 11-15% of total variation in annual blood pressure change.

Adult↗
PubMed1988

Increased platelet and vascular smooth muscle reactivity to low-dose adrenaline infusion in mild essential hypertension.

During low-dose adrenaline infusion, platelet count, platelet size, plasma beta-thromboglobulin (BTG) and forearm vascular resistance (FVR) were measured in twelve 40-year-old men with mild, untreated hypertension. The average platelet count increased from 195 to 226 X 10(9)/l (P less than 0.001), platelet size from 7.31 to 7.53 X 10(-15)/l (P less than 0.01), BTG from 0.61 to 1.08 nmol/l (P less than 0.02) and FVR decreased from 97 to 58 (arbitrary units; P less than 0.001) during the infusion. The change in platelet count reflects splenic release of platelets, the change in plasma BTG reflects platelet release reaction, while the reduced FVR reflects vascular smooth muscle cell relaxation. In 11 normotensive men aged 40 years, platelet count increased from 187 to 201 X 10 g/l (P less than 0.01) during an equal low-dose adrenaline infusion. This increase in platelet count is significantly less than in the hypertensive group (P less than 0.01). There was statistically no significant change in platelet size, BTG or FVR in the normotensive group. Arterial adrenaline rose from 0.5 to 2.5 nmol/l in the hypertensive and from 0.5 to 2.4 nmol/l in the normotensive group. A third group of 12 normotensive men received saline infusion: neither platelet parameters nor FVR changed in this group. Thus, a small and equal dose of adrenaline elicited a greater increase in platelet count, an enhanced platelet release reaction and a more pronounced forearm vasodilation in hypertensive than in normotensive subjects.

Adult↗
PubMed1988

Hyper-responsiveness to low-dose epinephrine infusion in mild essential hypertension.

The present study was undertaken to evaluate the effects of intravenous infusion of small amounts of epinephrine on haemodynamics, renal electrolyte excretion and blood platelets in essential hypertension. Arterial plasma epinephrine concentrations were increased during the infusion to approximately 2.5 nmol/l both in a group of 40-year-old men with untreated mild essential hypertension (blood pressure 154 +/- 3/100 +/- 3 mmHg, n = 12) and in a group of age-matched male controls (124 +/- 3/78 +/- 2 mmHg, n = 11). In the hypertensive group only, mean blood pressure decreased, forearm blood flow increased, forearm vascular resistance decreased (P less than 0.001 for all) and the urinary excretion of sodium and potassium increased (P less than 0.01 for both). The hypertensive group also responded with an increase in plasma beta-thromboglobulin (P less than 0.05), blood platelet size (P less than 0.05) and a higher increase in platelet counts than in the normotensive group (P less than 0.05). Thus, in several ways the hypertensive patients showed a hyper-responsiveness to amounts of epinephrine which corresponds well to the plasma concentration achieved during psychological and physical activity.

Adult↗