Biomedical subjects

I Ringqvist

Publications and source records attributed to I Ringqvist.

At least 55 records · Page 3Linked to original sources

PubMed1995

Cold exposure increases cyclic guanosine monophosphate in healthy women but not in women with Raynaud's phenomenon.

OBJECTIVE: To investigate influence of whole-body cooling on cyclic GMP (cGMP) in women with Raynaud's phenomenon and in healthy women. DESIGN: The study was performed as an open, parallel-group comparison between women with Raynaud's phenomenon and healthy women during the winter month of February. SETTING: The municipality of Västerås (Sweden). PARTICIPANTS: The Raynaud group comprised 24 female patients. The control group consisted of 21 healthy females. MAIN OUTCOME MEASURE: The venous levels of cGMP were measured on three different occasions: just before and after 40 min of whole-body cooling and after 20 min rest at room temperature (21 degrees C). RESULTS: Venous cGMP increased significantly in the control group after cold exposure (mean difference 0.43 pmol mL-1; 95% CI, 0.018-0.848; t = 2.18; df = 20; P = 0.02) and remained at a high level after 20 min rest (mean difference 0.58 pmol mL-1; 95% CI, 0.063-1.108; t = 2.34; df = 20; P = 0.015). In contrast, the levels of venous cGMP in the Raynaud group did not change significantly. The difference in increase between the two groups was significant (P < 0.02). The diastolic blood pressure in the Raynaud group increased after 40 min of whole-body cooling and was still significantly increased (P < 0.001) after 20 min rest at room temperature (21 degrees C). CONCLUSION: These results indicate that women suffering from Raynaud's phenomenon lack the physiological response of cGMP to cold exposure, which may explain their increased vasospastic response.

Adult↗

PubMed1994

Magnesium sulphate infusion decreases circulating calcitonin gene-related peptide (CGRP) in women with primary Raynaud's phenomenon.

The effects of two different vasodilating agents (MgSO4 infusion and the calcium antagonist nifedipine) on circulating levels of calcitonin gene-related peptide (CGRP) were studied in 12 women with pronounced primary Raynaud's phenomenon (PRP) and in 12 healthy females. There were no significant differences with regard to basal levels of circulating CGRP between women with PRP and the control group; median 15.5 (range 10-48) vs. 14 (range 10-69) pmol l-1, respectively. However, treatment with MgSO4 infusion significantly decreased circulating CGRP in women with PRP only from median 15.5 (range 10-48) to 10 (range 10-110) pmol l-1) (P < 0.05). On the other hand 14 days of treatment with nifedipine did not affect circulating CGRP in either of the investigated groups. Erythrocyte magnesium (ery-Mg) levels increased significantly after MgSO4 infusion in women with PRP (2.43 +/- 0.13 vs. 2.52 +/- 0.15 mmol l-1, P < 0.05) but not in the controls (2.51 +/- 0.24 vs. 2.57 +/- 0.28 mmol l-1, ns). In conclusion, the decrease of circulating CGRP after MgSO4 infusion in women with PRP provides further evidence that magnesium plays a significant role in the pathophysiology of PRP.

Adult↗

PubMed1994

The concentration of magnesium in erythrocytes in female patients with primary Raynaud's phenomenon; fluctuation with the time of year.

The magnesium (Mg) concentration was measured in erythrocytes of 30 women with pronounced primary Raynaud's phenomenon (PRP) and of 33 age-matched healthy control women. The measurements were made at three different times, six months apart. The mean Mg concentration in the PRP group and the control group differed significantly at each measurement. The values for the two groups were, respectively, 1.64 +/- 0.21 and 2.02 +/- 0.21 mmol/L (P < 0.001) in February, 1988; 2.16 +/- 0.21 and 1.85 +/- 0.21 mmol/L (P < 0.001) in August, 1988; and 2.01 +/- 0.21 and 2.37 +/- 0.20 mmol/L (P < 0.001) in January, 1989. The erythrocyte Mg level varied significantly with the time of year in both groups. In the PRP group the mean value was significantly higher in August than in the two winter months, but in the control group it was significantly lower in August. The authors conclude that women with PRP have a significantly lower magnesium concentration in erythrocytes during winter than the healthy controls and that this concentration varied with the season of the year in both groups.

Adult↗

PubMed1994

Effect of magnesium sulfate infusion on circulating levels of noradrenaline and neuropeptide-Y-like immunoreactivity in patients with primary Raynaud's phenomenon.

The effect of a short-term magnesium sulfate (MgSO4) infusion on venous plasma concentration of noradrenaline (NA) and neuropeptide-Y-like immunoreactivity (NPY-LI) was investigated in 12 women with primary Raynaud's phenomenon (PRP) and in 12 healthy matched controls. The Raynaud's patients did not demonstrate any significant changes in mean basal plasma NA concentration (0.29 +/- 0.15 vs 0.37 +/- 0.09 ng/mL, ns) after MgSO4 infusion. However, in the controls there was more than twice the amount of circulating noradrenaline (cNA) (0.21 +/- 0.14 vs 0.54 +/- 0.22 ng/mL, P < 0.001) after MgSO4 infusion, compared with the preinfusion value. Measurements during the cold pressor test prior to the MgSO4 infusion showed a significant increase of cNA in both the PRP group and the control group (from 0.29 +/- 0.15 to 0.33 +/- 0.16 ng/mL, P < 0.05, and from 0.21 +/- 0.14 to 0.29 +/- 0.16 ng/mL, P < 0.005, respectively). After MgSO4 infusion the levels of cNA during the cold pressor test increased significantly only in the PRP group (from 0.37 +/- 0.09 to 0.41 +/- 0.11 ng/mL, P < 0.05). Circulating NPY-LI concentrations increased significantly during MgSO4 infusion in the Raynaud's patients as well as in the controls from 105 +/- 21 to 127 +/- 23 pmol/L, P < 0.05, and from 107 +/- 17 to 132 +/- 27 pmol/L, P < 0.01, respectively. There were no detectable changes during the cold pressor tests in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Sympathetic activation after two weeks of nifedipine treatment in primary Raynaud's patients and controls.

The effect of a standardized cold pressor test on circulating noradrenaline and neuropeptide-Y-like immunoreactivity was investigated in 12 women with primary Raynaud's phenomenon and 12 healthy female controls before and after 2 weeks of treatment with the calcium antagonist, nifedipine. Measurement before treatment showed significant increase during the cold pressor test on circulating noradrenaline in both the primary Raynaud's phenomenon group and in the control group (from 0.29 +/- 0.15 ng/ml to 0.33 +/- 0.16 ng/ml, p < 0.05, and from 0.21 +/- 0.14 ng/ml to 0.29 +/- 0.16 ng/ml, p < 0.005, respectively). However, treatment with nifedipine resulted in significantly increased levels of circulating noradrenaline during the cold pressor test only in the control group (from 0.43 +/- 0.21 ng/ml to 0.50 +/- 0.20 ng/ml, p < 0.01). Plasma concentrations of neuropeptide-Y-like immunoreactivity were unchanged by the standardized cold pressor test, whether performed before or during nifedipine treatment in both groups. Nifedipine treatment per se significantly increased circulating noradrenaline in both the primary Raynaud's phenomenon patient group and in the control group (from 0.29 +/- 0.15 to 0.49 +/- 0.13 and 0.21 +/- 0.14 to 0.43 +/- 0.21 ng/ml, respectively, p < 0.001). Similarly, the circulating neuropeptide-Y-like immunoreactivity significantly increased in both the primary Raynaud's phenomenon group and in the control group (from 105 +/- 21 to 137 +/- 19 pmol/l and 107 +/- 17 to 147 +/- 13 pmol/l, respectively, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed1993

Effects of cold pressor test on circulating atrial natriuretic peptide 99-126 (ANP) in patients with Raynaud's phenomenon and influence of treatment with magnesium sulphate and nifedipine.

The effect of a standardized cold pressure test (CPT) on the venous concentration of immunoreactive atrial natriuretic peptide (irANP) was studied in 12 females with primary Raynaud's phenomenon (PRP) and 12 female age-matched controls. The test was performed at the end of three stages. During the first stage no medication was given. During the second stage a magnesium infusion was given. After fourteen days of medication with a calcium antagonist (Nifedipine) the third stage of the study was performed. The venous irANP increased significantly (P < 0.05) 10 min after the start of the CPT both in the PRP group and in the control group (136 +/- 39 to 159 +/- 54 and 153 +/- 45 to 179 +/- 40 pg ml-1, given as mean and SD). Baseline irANP did not change in the PRP group after treatment with magnesium or nifedipine. In the control group nifedipine treatment significantly (P < 0.01) lowered venous irANP compared to the no treatment or magnesium sulphate infusion stages (128 +/- 31 vs. 153 +/- 45 and 160 +/- 41 pg ml-1). After the CPT in both PRP group and control group the venous irANP did not increase either during magnesium sulphate infusion or nifedipine treatment. In conclusion the study has demonstrated that a standardized CPT results in a delayed increase in irANP in venous plasma and that magnesium sulphate infusion and nifedipine treatment prevent this increase. Furthermore, our data do not suggest a role for irANP in the symptomatology of primary Raynaud's phenomenon.

Adult↗

PubMed1992

Diagnostic and prognostic importance of ST recording after an episode of unstable angina or non-Q-wave myocardial infarction.

The diagnostic and prognostic value of ST recordings in unstable coronary artery disease were evaluated in 198 men below 70 years of age admitted to the coronary care unit because of chest pain due to myocardial ischaemia but without the development of Q-wave infarction. The ST recordings were performed for 24 h in bed in the CCU (n = 75) between 6 and 66 hours after the last episode of pain, before discharge during ambulation in hospital 4-6 days after admission (n = 198), and ambulatory out of hospital 1 month later (n = 109). The long-term ECG was registered from bipolar leads corresponding to V2 and V5 using two-channel FM-recorders. Significant ST episodes were defined as ST segment deviation greater than or equal to 0.1 mV from baseline and lasting for at least 1 min. During the recordings 85-90% of the patients were treated with betablockers and 27-41% also with calcium channel blockers. In the CCU recordings, ST depression occurred in 23% of the patients, 21% had asymptomatic and 7% symptomatic episodes. Before discharge the ST recordings showed ST depression in 18% of the patients, 16% asymptomatic and 7% symptomatic. Ambulatory monitoring after 1 month showed a higher occurrence of ST depressions--33% (P less than 0.01 compared to day 5), 26% had episodes without pain and 13% painful episodes.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed1990

The effect of felodipine on cold-induced digital vasospasm.

Felodipine, a calcium antagonist with pronounced vascular selectivity, was given to 10 patients with cold-induced, digital vasospasm. Placebo and increasing doses of felodipine (2.5, 5, and 10 mg b.i.d.) were given for 2 weeks each. There was a significant decrease in systemic, but not in digital, blood pressure and a significant increase in heart rate during felodipine treatment. The subjective rating of symptoms improved significantly on all doses. No significant effect on cold-induced digital vasospasm during local cooling to 15 and 10 degrees C was registered. Typical side effects of calcium-entry blockers were reported. Moreover, two postmenopausal women reported recurrence of menstrual bleeding and one woman reported vaginal hemorrhagic discharge during treatment. In conclusion, felodipine, although causing a significant, symptomatic relief, had no significant effect on cold-induced digital vasospasm when objective measures were used.

Blood Pressure↗

PubMed1990

Lower serum magnesium level after exposure to cold in women with primary Raynaud's phenomenon.

Serum levels of magnesium (s-Mg), calcium (s-Ca), potassium (s-K) and sodium (s-Na) were measured in 80 women with primary Raynaud's phenomenon (RP) and in 24 age-matched female controls recruited from a population survey. The blood samples were taken after a 40-min standardized whole body cooling test. The mean s-Mg level in the group with RP was significantly lower than in the controls (0.81 +/- 0.05 vs. 0.86 +/- 0.07 mmol l-1, P less than 0.05). One year later, 66 members of the RP group and 22 members of the control group were investigated further, but without any exposure to cold. No differences in mean s-Mg values were found between the groups. The mean s-Mg level was significantly higher in the blood samples taken later without cold exposure than at the initial examinations after exposure to cold in the RP group, but not in the controls. The s-Mg level was lower after exposure to cold in 82% of the women with RP, compared to 45% of the controls (P less than 0.001). No differences in the other electrolytes were found. It is concluded that exposure to cold under standardized conditions may decrease the s-Mg level in women with primary RP. Further studies of the role of magnesium in patients with RP are required.

Adult↗

PubMed1989

The effect of isradipine, a new calcium-channel antagonist, in patients with primary Raynaud's phenomenon: a single-blind dose-response study.

Isradipine is a new potent calcium-channel blocking agent with highly selective action on peripheral vessels. In this single-blind study, its dose-related effect on cold-induced changes in finger systolic pressure (FSP) was investigated in ten female patients with primary Raynaud's phenomenon, and the side effects of isradipine treatment were evaluated. The patients were studied during 9 weeks of treatment. After 3 weeks of placebo, isradipine was given in doses of 1.25 mg b.i.d. and 2.5 mg b.i.d. for 3 weeks each. FSP was measured on local finger cooling to 10 degrees C. FSP at 10 degrees C expressed in percent of the value of 30 degrees C increased from 21 +/- 16% (M +/- SD) after placebo to 42 +/- 28% (p less than 0.05) and 62 +/- 25% (p less than 0.001) after treatment with isradipine 1.25 mg and 2.5 mg b.i.d., respectively. The subjective efficacy of the treatment was assessed with a visual analogue scale (VAS). The VAS rating increased from 17 (range 0-66) after placebo to 39 (range 12-88) (NS) and 68 (range 25-99) (p less than 0.001) after isradipine treatment with 1.25 mg and 2.5 mg b.i.d., respectively. Adverse effects of isradipine therapy were few and did not differ from those reported after the placebo period. This single-blind, dose-response study showed that isradipine in doses of 1.25 mg and 2.5 mg b.i.d. had favorable objective and subjective effects in patients with primary Raynaud's phenomenon and had no serious side effects.

Adult↗

PubMed1989

Validity of a postal questionnaire with regard to the prevalence of myocardial infarction in a general population sample.

In order to evaluate the possibility of finding persons who have suffered a myocardial infarction (MI) by postal questionnaire, a self-administered questionnaire was sent to a random sample of 4400 men aged 45-64 years, drawn from the general population. The response rate was 95%. 176 men indicated that they had been hospitalized for MI, out of which 124 cases could be verified from medical records. Of the remaining men, 33 had evidence of cardiovascular disease (CVD) in their records but no MI, and 19 men had no evidence of CVD. The sensitivity (estimated from a subsample) was 100% and the specificity 98.7%. The predictive value was 100% for a negative response and 70.5% for a positive response. The 33 positive responders whose MI could not be verified but who had evidence of CVD had characteristics fairly similar to the responders with verified MIs. However, the 19 positive responders whose MI could not be verified and who had no evidence of CVD had characteristics that were dissimilar from the MI group as well as from the negative responders. The questionnaire thus identified all the MI cases. The need for validation can be limited to the relatively small group of positive responders.

Cardiovascular Diseases↗

PubMed1989

Diagnostic value of longterm ambulatory ECG in patients with syncope, dizziness or palpitations.

The diagnostic value of longterm ambulatory ECG recording (LTER) was determined in 63 patients referred for investigation of syncope, in 32 with dizziness and in 89 with palpitations. Among patients referred for syncope, dizziness or palpitations 8, 13 and 54%, respectively, had typical symptoms during the recording with concomitant arrhythmia explaining the symptom, and 6, 50 and 11% had a typical symptom without concomitant arrhythmia. In 12 and 3% of the patients referred for syncope or dizziness, respectively, arrhythmia was observed and probably explained their previous complaint, but no symptoms occurred during LTER. LTER was found to be of diagnostic value in 24% of the patients with syncope, in 66% of those with dizziness and in 65% of those with palpitations. In the latter two groups the presence of symptoms the week before the start of these recordings predicted the occurrence of symptoms during LTER. Only occasionally was there a higher yield of typical symptoms beyond 48 h of recording.

Aged↗

PubMed1989

Deduction of biphasic phase response curves from ventricular parasystole.

The mechanisms behind ventricular premature beats may be divided into two main categories, reentry and modulated parasystole. Although it is relatively easy to distinguish among arrhythmia generating mechanisms on the cellular level, it is far more difficult in the clinic. Modulation of ventricular parasystole by sinus beats has been shown to result in a biphasic phase response curve. Two cases are reported where the deduction of such phase response curves from long-term ECG recordings is discussed and described as a stepwise procedure.

Aged↗

PubMed1989

Deduction of triphasic phase response curves from ventricular parasystole.

Modulation of ventricular parasystole by sinus beats has been shown to result in a biphasic phase response curve. Some reports also indicate that the modulation effect could be described by a triphasic response with an early phase of acceleration, which would correspond to the supernormal phase of excitability. Two cases of such triphasic phase response curves are reported. The coexistence of ventricular couplets and parasystole is also discussed. The second beat of the couplet has often been explained by reentry or reflection, but could also be interpreted as due to supernormal modulation, resulting in an accelerated second ectopic response.

Aged↗

PubMed1988

Propafenone versus disopyramide for treatment of chronic symptomatic ventricular arrhythmias. A multicenter study.

The efficacy and safety of propafenone, 150 mg four times daily, were compared with those of disopyramide, 100 mg four times daily, in a randomized single-blind, cross-over study in 38 patients with symptomatic premature ventricular complexes (PVCs). The 24-hour ambulatory ECG, employed for assessing antiarrhythmic efficacy, was analyzed blindly. The median reduction in the number of PVCs was higher with propafenone than with disopyramide (91.4% vs. 63.5%, respectively, p less than 0.01). A reduction of at least 80% was achieved by propafenone in 22 (59%) and by disopyramide in 16 patients (43%) (NS). Ventricular tachycardias (VTs) were abolished by propafenone in eight out of 11, and by disopyramide in five out of nine patients with VTs (NS) a possible proarrhythmic effect was seen in three patients during disopyramide and in one patient during propafenone treatment. Micturition disturbances (p less than 0.001) and a dry mouth (p less than 0.01) were more commonly associated with disopyramide than with propafenone. In conclusion, in the given dosages, propafenone was superior to disopyramide in suppressing PVCs and had fewer side-effects.

Adult↗

PubMed1988

Total lung capacity measured by body plethysmography and by the helium dilution method. A comparative study in different patient groups.

The helium dilution method is known to underestimate the total lung capacity (TLC) in patients with poorly or non-ventilated areas in the lungs. The standard plethysmographic method has been reported to overestimate TLC in patients with severe airway obstruction. To determine the magnitude of the difference between the two methods, a comparison was made in different patient groups. In a group of patients with normal lung function tests (n = 20) there was a small but significant average difference in TLC between plethysmography and the helium dilution method, the larger values being obtained with the latter. In patient groups with moderately obstructed airways (n = 23), severely obstructed airways (n = 20), or emphysema (n = 19), there were no significant average differences, although in two patients in the emphysema group the plethysmographic values were considerably larger than those obtained by helium dilution. We conclude that the gas dilution methods and plethysmography with a pressure-compensated volume displacement plethysmograph gave estimates of TLC which agreed even in patients with airway obstruction or emphysema, except in patients with very severe lung disease.

Emphysema↗

PubMed1987

Distribution patterns of ventricular premature complexes at different heart rates.

The relation between distribution patterns of ventricular premature complexes (VPCs) and heart rate in Holter recordings abundant in VPCs was analyzed using computer-assisted determination of the number of interectopic sinus beats at different heart rates. Within the complete 24-hour heart rate spectrum, zones were demonstrated that were characterized by manifest or concealed bigeminy or manifest or concealed trigeminy. Bigeminy zones were found in 26 and trigeminy zones in 21 of 42 patients. Bigeminy zones were found at a significantly lower heart rate, on the average, then trigeminy zones. In 10 patients both bigeminy and trigeminy zones were observed. Bigeminy and trigeminy zones probably correspond to the distribution patterns of VPCs predicted from modulation of a pacemaker and reflected reentry, both of which can be induced by electrotonically mediated impulses across a zone of impaired conduction in isolated bundles of Purkinje fibers. The bigeminy and trigeminy zones will correspond at least partly to the entrainment zones found during electrotonic modulation of parasystolic foci. The bigeminy zones will correspond to 2:1 entrainment and the trigeminy zones mainly to 3:1 entrainment.

Adult↗

PubMed1987

The effect of the calcium-entry blocker nifedipine on cold-induced digital vasospasm. A double-blind crossover study versus placebo.

The effects of the calcium-entry blocker nifedipine 20 mg, two 10 mg capsules, t.i.d. in patients with cold-induced digital vasospastic disease of idiopathic or traumatic origin was tested in 28 patients, using double-blind crossover technique on both symptoms and test results. The effect of treatment on digital blood pressure during local cooling was assessed using the Nielsen-Lassen method. Symptomatic improvement was reported by 5 patients during placebo treatment and 17 during nifedipine treatment (p less than 0.01). The symptomatic improvement was significant in the total group of patients and in the group of patients with idiopathic vasospastic disease. The digital blood pressure during local cooling improved significantly with nifedipine at 5, 10, 15 (p less than 0.001) and 20 degrees C (p less than 0.05) for the total study population and for the two subgroups except for the change at 20 degrees C in the IDIOP group. At a digital temperature of 10 degrees C, 2 patients reached normal digital blood pressure during placebo treatment compared to 16 during nifedipine treatment (p less than 0.001). The number of side-effects increased significantly (p less than 0.05) during nifedipine treatment. We consider the use of nifedipine in patients with cold-induced digital vasospastic disease to be of great value, especially in patients with digital vasospastic disease of idiopathic origin.

Adult↗