The concentration of protein-compounds in interstitial tissue of patients with chronic critical limb ischaemia and oedema.

BACKGROUND: Many of chronic critical limb ischaemia (CLI) patients have distal leg and foot oedema. Previous electronmicroscopic studies have shown that chronic severe ischaemia may cause hypoxic damage of the capillary endothelium, including morphological changes i.e. multiplicated/thickened basal lamina, and formation of interendothelial gaps. To assess the functional consequences of these morphologic derangements, where proteins can leak through, we investigated the composition of the interstitial fluid in oedematous ischaemic limbs. PATIENTS AND METHODS: Nine female and 3 male patients with a mean age of 79 +/- 7.9 years were included. All had unilateral CLI and peripheral pitting oedema. Leg and foot volume was measured with water displacement volumetry. Blister suction technique was used to collect subcutaneous interstitial fluid. The concentration of albumin, transferrin, immunoglobulin G and alpha 2-macroglobulin in plasma and blister fluid was measured by immunoturbidimetry. Nine patients, 8 women and 1 man with a mean age of 83 +/- 5.5 years with a proximal femur fracture served as an age-matched control group. RESULTS: The mean concentration of albumin in blister fluid was significantly lower in the patients, whereas the mean concentration of alpha 2-macroglobulin in blister fluid did not differ between patients and controls. Mean ratio between concentrations in blister and serum of albumin, transferrin and immunoglobulin G in the limbs with CLI and oedema were significantly lower than respective values in the control group. However, there was no significant difference in the ratio of alpha 2-macroglobulin between these groups. CONCLUSION: A higher transcapillary concentration gradient for proteins in CLI limbs signifies an increase in the net osmotic pressure gradient across the capillary wall, which may be a potential oedema limiting factor.

HFE gene mutation (C282Y) and phenotypic expression among a hospitalised population in a high prevalence area of haemochromatosis.

BACKGROUND: Previous studies have shown that up to 0.5% of the Caucasian population is homozygous for the HFE gene C282Y mutation. High prevalence values have been reported in Northern Europe. To what extent the presence of this mutation is associated with overt clinical haemochromatosis is unclear. AIM: To determine the prevalence of the C282Y allele in a hospitalised population of an acute medical department, and study the phenotypic expression in the homozygotes. METHODS: Blood samples were obtained from 2027 hospitalised patients; 1900 Caucasians and 127 non-Caucasians. Serum iron, transferrin, and ferritin were measured at admission. The presence of the HFE gene mutation was determined by polymerase chain reaction based analysis. Follow up fasting blood samples were obtained from patients homozygous for the mutation. RESULTS: Fourteen of the 1900 Caucasian subjects (0.74%) were homozygous and 224 (11.8%) were heterozygous for the C282Y mutation, including 32 subjects (1.7%) who were compound heterozygous for the C282Y and H63D mutations. Ten of 14 (71%) homozygous patients displayed mild to moderate biochemical expression of haemochromatosis with a serum ferritin level <550 microg/l, two (14%) patients were "non expressing", and two of five in whom liver biopsies were carried out had cirrhosis, including one with advanced hepatocellular carcinoma. CONCLUSIONS: The prevalence of C282Y homozygosity in a hospitalised population was 0.74%. However, the majority of homozygous patients displayed mild to moderate biochemical expression. C282Y mutation screening may detect individuals that do not develop haemochromatosis. Transferrin saturation and ferritin, which are used as first line screening in haemochromatosis, may be highly unreliable in the presence of an inflammatory process.

High prevalence of the hemochromatosis-associated Cys282Tyr HFE gene mutation in a healthy Norwegian population in the city of Oslo, and its phenotypic expression.

BACKGROUND: Previous studies have shown that 5%-10% of white subjects are heterozygous for the HFE gene C282Y mutation, which is associated with hemochromatosis. The aim of our study was to determine the prevalence of heterozygosity and homozygosity for the C282Y HFE gene mutation and its phenotypic expression in a group of healthy Norwegians. METHODS: Fasting blood samples were obtained from 505 unrelated hospital employees. Serum iron, transferrin, and serum ferritin were measured. Transferrin saturation was calculated. The presence of HFE gene mutation was determined with a polymerase chain reaction-based analysis. RESULTS: Two of the 505 subjects (0.4%) were homozygous and 75 (14.9%) were heterozygous for the C282Y mutation. Median serum ferritin among the heterozygotes was 59 microg/l, compared with 47 microg/l among individuals without the C282Y mutation (P = 0.12). Median transferrin saturation among the heterozygotes was 31%, compared with 24% among individuals without C282Y mutation (P < 0.001). Twenty-three individuals (4.6%) had a serum ferritin level > 200 microg/l. Eight of these (35%) had the C282Y mutation: two homozygotes and six heterozygotes. Transferrin saturation > 50% was observed in 25 individuals (5.0%). Twelve of these (48%) had the C282Y mutation; two were homozygotes and 10 heterozygotes. Only eight individuals (1.6%) had a transferrin saturation > 60%: one homozygote, five heterozygotes, and two individuals without mutation. CONCLUSIONS: Fifteen per cent of a healthy Norwegian population is heterozygous for the HFE gene mutation C282Y. This is among the highest reported prevalence values among healthy individuals. Half of the subjects with transferrin saturation greater than 50% were carriers of the C282Y mutation.

Older adults and the news media: utilization, opinions, and preferred reference terms.

We surveyed 868 community-dwelling older adults about their (a) utilization of media news, (b) opinion of news media coverage of older people, and (c) preferences among terms used by news media to refer to senior citizens. Those with more than high school education read more newspaper news than those with less education. All groups watched TV news more frequently than they read the newspaper. Respondents had reservations about the news media's accuracy in, attitude toward, and interest in stories regarding seniors. Clear education and gender-related patterns emerged, whereas age proved nonsignificant in many analyses. Respondents' preferred reference terms were: (nouns) senior citizen, retiree, senior, and older adult; (adjectives) retired, senior, and mature. Respondents disliked: (nouns) old man/woman, old person, oldster, old timer, and geezer; (adjectives) old, aged, gray, and geriatric.

Density of L-type calcium channels in ischaemically preconditioned porcine heart regions.

Ischaemic preconditioning by brief ischaemic episodes could be explained by reduced cellular calcium ion (Ca2+) influx, reduced cytosolic Ca2+ overload and delayed cell-injury during subsequent long-lasting ischaemia. L-type calcium channels (LCC) regulate sarcolemmal Ca2+ influx in myocardial cells. The aim of this study was to investigate if preconditioning was associated with reduced density or altered state of LCC in the preconditioned region of the heart. To test this we compared the density and the dissociation constant of (+)-[3H]isradipine binding to LCC in membranes from preconditioned and control regions of porcine hearts. Eight porcine hearts were regionally preconditioned by two 10-min occlusions of the mid left anterior descending artery, and each occlusion was followed by 30 min of reperfusion. Biopsies were taken from the preconditioned regions and control regions supplied by the circumflex artery at the end of the last reperfusion, and (+)-[3H]isradipine binding to membranes made from the biopsies was measured. The differences in density and dissociation constant of (+)-[3H]isradipine binding to LCC in membranes from preconditioned and control regions were not significant. In conclusion, the proposed effect of ischaemic preconditioning to reduce Ca2+ influx, does not involve local changes in density or state of LCC that could be detected by (+)-[3H]isradipine binding.

Cardiac adaptation to one hour of mild regional low flow ischaemia in the pig.

OBJECTIVE: The aim was to determine the cardiac consequences of a 1 h period of mild regional low flow ischaemia in the pig heart. METHODS: In eight pentobarbitone sodium anaesthetised pigs (weight range 23-38 kg), the mid left anterior descending coronary artery was constricted by a hydraulic occluder. Transmural coronary blood flow (Doppler flowmetry) was reduced to approximately 70% of control for 1 h. After complete release of the occluder cardiac function was monitored for 2 h. Left ventricular segment lengths were continuously recorded in the region subjected to low flow ischaemia and in a control region supplied by the circumflex artery. RESULTS: After 1 h with a 28(SEM 3)% reduction in coronary blood flow, the systolic shortening index decreased from 100 to 68(7) (p < 0.001). This index transiently normalised upon reperfusion. Thereafter it declined, reaching a nadir of 72(5) at 1.25 h of reperfusion, and subsequently improved to 82(6) at 2 h of reperfusion. CONCLUSIONS: Normalisation of local myocardial function appears during the first minutes of reperfusion after 1 h of mild low flow ischaemia and is followed by a period of stunning.

Effect of cold pressor test and awareness of hypertension on platelet function in normotensive and hypertensive women.

Plasma beta-thromboglobulin (beta-TG) concentration, reflecting platelet function in vivo, was compared in fertile women with untreated essential hypertension and age-matched normotensives, in two separate studies. In the first study, hypertensives and normotensives were aware of their blood pressure status. Blood was sampled through arterial and venous indwelling catheters, and no difference in beta-TG was found between the groups. Arterial beta-TG was significantly lower than venous concentration (p < or = 0.05). Cold pressor test increased arterial beta-TG significantly in both groups (p < 0.05). In the second study, both women and investigator were unaware of blood pressure status, and beta-TG concentration, platelet count, and mean platelet volume obtained by venipunctures were similar in the hypertensive and normotensive group. Thus, platelet function in vivo seems to be normal in fertile hypertensive women, in contrast to the platelet dysfunction previously reported in hypertensive men. In women, as in men, platelet release occurred during venous catheter blood sampling and during cold pressor test. However, at variance from men, platelet function was not influenced by awareness of blood pressure status in the hypertensive females.

Sex differences in essential hypertension.

A group of 41-year-old hypertensive men (n = 35, blood pressure (BP) 149.9 +/- 2.1/98.9 +/- 1.1 mmHg, mean +/- SEM) who had never received treatment for their condition were compared with hypertensive women of the same age (n = 18, BP 155.9 +/- 4.3/98.1 +/- 1.6 mmHg) with comparable body mass index (BMI, 25.9 +/- 0.5 vs. 24.9 +/- 4.5 kg m-2) who, also, had never received treatment. The lipid profile was more atherogenic in the men, with lower HDL cholesterol (1.21 +/- 0.04 vs. 1.38 +/- 0.06 mmol l-1, P = 0.04), higher total cholesterol (6.04 +/- 0.14 vs. 5.54 +/- 0.18 mmol l-1, P = 0.04) and triglycerides (1.80 +/- 0.16 vs. 0.96 +/- 0.10 mmol l-1, P < 0.001). The hypertensive men had higher haemoglobin (P < 0.001) and haematocrit. Plasma catecholamines were inversely related to BMI in the women only (r = -0.52, P < 0.05 for both noradrenaline and adrenaline). Women with BMI above 25 kg m-2 had significantly lower arterial plasma adrenaline and noradrenaline than those with BMI below 25 kg m-2 (28 +/- 5 vs. 78 +/- 16 pg ml-1, P < 0.01 and 101 +/- 17 vs. 206 +/- 33 pg ml-1, P < 0.01 respectively). A negative curvilinear relationship appeared between arterial adrenaline and insulin (r = 0.49, P = 0.05). These results suggest a male propensity for athero-thrombogenic risk factors in otherwise comparable hypertensive subjects. A close relationship between metabolic risk factors within the normal range seems to exist even in hypertensive women. The decreased sympathetic activity at rest in the obese hypertensive women indicates different pathophysiological mechanism for hypertension in lean and obese. Decreased sympathetic activity and thus reduced energy expenditure, promotes a risk for weight gain, and could explain the inverse relationship between insulin and adrenaline.

Role of adenosine for reactive hyperemia in normal and stunned porcine myocardium.

The role of adenosine for reactive hyperemia in normal and stunned myocardium was examined in 16 open-chest barbiturate-anesthetized pigs. Interstitial adenosine concentration was reduced or enhanced by intracoronary infusion of adenosine deaminase or the nucleoside transport inhibitor R 75231, respectively. In normal myocardium, adenosine deaminase reduced volume of hyperemia (Doppler flowmetry) after a 30-s left anterior descending coronary artery (LAD) occlusion by 20% (6-34%; P < 0.05), whereas R 75231 increased volume of hyperemia by 15% (2-24%; P < 0.05). Adenosine deaminase reduced volume of hyperemia after a 2-min LAD occlusion by 27% (13-37%; P < 0.001), whereas R 75231 increased volume of hyperemia by 66% (53-159%; P < 0.001). Adenosine deaminase and R 75231 did not affect maximal hyperemia. Volume of hyperemia after a 2-min LAD occlusion was reduced in stunned myocardium (%systolic segment length shortening reduced by approximately 45%, ultrasonic technique) but not further altered by either adenosine deaminase or R 75231. These findings show that adenosine contributes to reactive hyperemia after 30-120 s of ischemia in normal myocardium and indicate that the reduced reactive hyperemia in stunned myocardium is due to reduced accumulation of adenosine during ischemia.

Myocardial potassium balance associated with regional ischaemia in the pig: effects of beta-adrenoceptor blockade, duration of ischaemia and preceding ischaemic periods.

The effects of beta-adrenoceptor blockade, duration of ischaemia and preceding ischaemic periods on ischaemia-induced changes in myocardial K+ balance were studied in 12 open-chest pigs. Coronary venous blood was directed through a shunt from the coronary sinus to the right atrium. Continuous recordings of arterial, shunt blood [K+] and shunt flow enabled us to compute myocardial K+ balance during and after consecutive 2-, 2-, 5-, 10- and 2-min periods of regional ischaemia separated by 30 min of reperfusion. beta-adrenoceptor blockade (propranolol 1 mg kg-1 i.v.) given between the first and second ischaemic period did not alter the effects of 2 min ischaemia on myocardial K+ balance. Total K+ losses induced by 2, 5 and 10 min of ischaemia were 67.1 (40.6-93.3), 106.7 (69.4-176.8) and 192.2 (117.7-332.6) mumol 100 g-1, respectively. Thus, the plateau observed in extracellular [K+] between 2 and 10 min of regional ischaemia could, at least partly, be explained by continuous drainage of K+ from ischaemic myocardium into the surrounding normally perfused tissue. The total K+ loss induced by the second and last 2-min ischaemic period were 67.1 (40.6-93.3) and 35.6 (23.1-53.6) mumol 100 g-1 (P less than 0.001), respectively. This reduction shows that ion homeostasis during ischaemia was greatly changed in myocardium which had been 'preconditioned' and 'stunned' by 5 plus 10 min of ischaemia. Total amount, maximal rate and duration of post-ischaemic K+ reuptake increased with the duration of the preceding ischaemia. Moreover, K+ re-uptake after 2 min of ischaemia and the number of sarcolemmal Na/K pumps ([3H]ouabain binding), were normal in stunned myocardium. From these observations we conclude that progressive stimulation of the Na/K-pump occurred when ischaemia was prolonged from 2 to 10 min, and that Na/K-pump function was preserved in stunned myocardium.

Faster and more reliable absorption of adrenaline by aerosol inhalation than by subcutaneous injection.

1. The aim of the present study was to compare absorption of adrenaline given by aerosol spray inhalation with absorption after subcutaneous injection. 2. Arterial plasma adrenaline was measured in nine healthy volunteers following adrenaline administration by both methods. 3. Following inhalation of 20 puffs of adrenaline aerosol, 0.15 mg/puff, a peak arterial adrenaline concentration after 1 min and a rapid fall to baseline from this peak occurred. 4. When given by subcutaneous injection absorption was slower with a peak arterial adrenaline concentration after 4 min. The fall in arterial adrenaline from this peak level was not statistically significant within 30 min after injection. 5. There was less intersubject variation of arterial adrenaline concentration following inhalation when compared with injection. 6. Heart rate, blood pressure and finger tremor followed the changes in arterial adrenaline concentrations. 7. These results indicate that absorption is more reliable when adrenaline is given by inhalation. The rapid fall in arterial adrenaline following inhalation, suggests that repeated inhalations are necessary when such adrenaline therapy is required.

Increased arterial adrenaline is related to pain in uncomplicated myocardial infarction.

Plasma levels of catecholamines, beta-thromboglobulin (BTG) and arginine vasopressin (AVP), and degree of pain were examined in 22 patients with suspected uncomplicated myocardial infarction within 24 h following onset of chest pain. Sixteen patients developed infarction with peak creatine phosphokinase at 1280 Ul-1 (range 293-3770 Ul-1). Fifteen healthy men served as controls (C). Arterial adrenaline levels were significantly higher in patients with pain (1.15 +/- 0.23 nmol l-1, n = 8, mean value +/- SEM) than in those without pain (0.60 +/- 0.10 nmol l-1, n = 14, P less than 0.05). Plasma catecholamines were moderately but significantly elevated in myocardial infarction; the concentration of arterial adrenaline was 0.83 +/- 0.14 nmol l-1 and that of arterial noradrenaline was 2.70 +/- 0.28 nmol l-1 compared with 0.44 +/- 0.04 nmol l-1 (P less than 0.025) and 1.47 +/- 0.05 nmol l-1 (P less than 0.0005), respectively, in C. One week later, plasma catecholamines had returned to baseline levels. Plasma BTG showed borderline elevation (1.0 +/- 0.1 pmol l-1) compared with C (0.6 +/- 0.1 pmol l-1, P = 0.04), and remained unchanged 1 week later. Plasma AVP was at baseline level. Uncomplicated myocardial infarction, regardless of size, was associated with only moderately increased sympathetic tone. Plasma adrenaline was related more to the degree of pain than to the presence of acute myocardial infarction. Arterial adrenaline may be a sensitive marker of sympatho-adrenal activity related to pain.

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.

Significance of right atrial function during right sided inotropic stimulation of pig hearts in situ.

Cardiac adjustments to inotropic stimulation of the right side of the heart were examined in anaesthetised, open chest pigs by calcium chloride infusion (80 mumol.min-1) into the right coronary artery. At stable haemodynamic conditions and at constant heart rate, right ventricular (RV) pre-ejection segment length increased by 4.6 (2.7-7.2) % (median, 95 % confidence interval) (p less than 0.01), RV end diastolic pressure rose from 5.3 (3.4-7.7) to 6.0 (3.6-8.8) mm Hg (p less than 0.05), and stroke volume rose by 6.8 (4.2-10.8) % (p less than 0.001). When the effect of right atrial contraction on RV filling was excluded by simultaneous pacing of atria and ventricles, the RV pre-ejection segment length no longer increased, and stroke volume rose by only 3.5 (0.1-9.5) % (p less than 0.05) during right side inotropic stimulation. Right atrial inotropic stimulation improves right ventricular filling, and may cause redistribution of blood from the systemic to the pulmonary circulation. This redistribution would raise the pulmonary vascular pressures, and thereby also improve left ventricular filling. The improved right ventricular filling partly accounts for the rise in RV output.

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.