Alteration of the fibrinogen molecule and its phosphorylation state in myocardial infarction patients undergoing thrombolytic treatment.

Fibrinogen was purified by protamine-agarose chromatography from plasma from three patients after their submission to hospital due to acute myocardial infarction. The total amount of phosphate bound to fibrinogen and the concentration of fibrinogen was determined in samples withdrawn immediately after submission and after thrombolytic treatment. Streptokinase treatment almost totally removed circulating fibrinogen while recombinant tissue plasminogen activator spared much of it. In patients treated with streptokinase, the new circulating fibrinogen was homogeneous according to the single alpha-band seen after sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis under reducing conditions, whereas fibrinogen from the recombinant tissue plasminogen activator-treated patient as well as healthy controls exhibited two alpha-bands in the 66-kDa region. The molar ratios of phosphate to fibrinogen of healthy controls and commercial fibrinogen were 0.82 (+/-0.04) and 0. 87 (+/-0.05), respectively. For two streptokinase-treated patients the degree of phosphorylation increased threefold from a normal range of 0.97 (+/-0.11) and 0.67 (+/-0.09) mol/mol fibrinogen before treatment to 3.33 (+/-0.32) and 1.86 (+/-0.17) mol/mol in newly formed fibrinogen on day 1. Recombinant tissue plasminogen activator treatment led to a smaller increase in phosphorylation, from 1.14 (+/-0.13) pretreatment to 1.65 (+/-0.11) after treatment on day 1. In conclusion we show in this report that after streptokinase treatment of patients with acute myocardial infarction, the new Aalpha-chain of fibrinogen was a homogeneous single 66-kDa band on sodium dodecyl sulphate polyacrylamide gel electrophoresis under reducing conditions and that the degree of phosphorylation of plasma fibrinogen was elevated, approaching the theoretical limit of 4 mol phosphate/mol fibrinogen.

[Brain damage caused by hypotensive anesthesia? Both the anesthetic technique and the anesthetic agent must be chosen with care]. / Cerebrala skador av hypotensionsnarkos? Anestesiteknik och narkosmedel måste väljas med omsorg.

During the fifty years since hypotensive anaesthesia, induced hypotension to minimise intraoperative blood loss, became an established routine, there have been few reports of associated cerebral complications. However, evidence of disturbed cerebral function among patients undergoing orthognathic surgery under induced hypotension was obtained in a recent study where the level of adenylate kinase activity in cerebrospinal fluid was used as a highly sensitive biochemical marker of brain cell injury. Moreover, psychometric tests revealed persistent postoperative mental deterioration. The underlying cause of brain cell injury seems to be complex, and as in all likelihood it is not hypotension per se that is responsible, the effect of the anaesthetic agents used (isoflurane and propofol) has to be considered. It was also noted that hypotension did not improve the clinical outcome of orthognathic surgery, as compared with comparable operations performed under normotension.

Erythrocytic protein kinase C activity in primary hypertension.

OBJECTIVES: Increased protein kinase C activity has been reported in erythrocytes from patients with primary hypertension and also from hypertensive rats. In this phenomenological study, we investigated whether a possible increased activity was the result of an augmented amount of enzyme molecules or a more active enzyme. DESIGN: Collect blood samples, separate erythrocytes from other blood cells. After partial purification of protein kinase C in the erythrocyte lysate, assay the enzyme activity under optimal conditions using a specific peptide substrate. SETTING: Central Hospital in Eskilstuna and University Hospital in Uppsala, Sweden. SUBJECTS: Healthy individuals: 47 persons (20 women and 27 men). Ten patients with untreated primary hypertension. MAIN OUTCOME MEASURES: Erythrocytes were separated from leucocytes and platelets by passing through a cellulose column followed by repeated washings. Some proteins in the erythrocyte lysate interfering with protein kinase C assay were removed by chromatography on DEAE-cellulose. RESULTS: The mean protein kinase C activity in erythrocytes from healthy individuals was 0.18 +/- 0.02 pmol [32P]phosphate min(-1) x 10(6) cells, regardless of sex and age. The corresponding value for patients with primary hypertension was 0.16 +/- 0.04 pmol [32P]phosphate min(-1) x 10(6) cells. CONCLUSIONS: The amount of protein kinase C, measured as the activity at optimal assay conditions, in erythrocytes from patients with primary hypertension is not critical for the development of moderate hypertension.

Disturbed energy balance in skeletal muscle of patients with untreated primary hypertension.

OBJECTIVE: It has been shown that the distribution of Na+ and Ca2+ in various cells is abnormal in patients with untreated primary hypertension, indicating an altered membrane permeability in these cells. This would activate certain ion pumps and thereby enhance ATP turnover. We investigated possible alterations in energy economy of skeletal muscle tissue. DESIGN: Skeletal muscle energetics were studied in vitro and in vivo in patients with untreated primary hypertension. Phosphocreatine (PCr), energy charge (EC) and total adenylate values were assessed. SETTING: The study was performed at the outpatient clinic of a general hospital and at a university clinical chemistry department and at a specialized bioenergetic laboratory. SUBJECTS: Altogether, 17 patients with untreated primary hypertension were examined together with matched, healthy and normotensive controls with normal body-mass index. MAIN OUTCOME MEASURES: Skeletal muscle biopsies were obtained from 10 patients and 10 controls for analysis of high energy phosphate compounds. Another seven patients were enrolled for in vivo NMR spectroscopy. RESULTS: We found a decrease of 30% (P < 0.01) of PCr content in the patients, whilst EC and total adenylates were unchanged. Nuclear magnetic resonance spectroscopy showed an abnormal decrease of PCr during exercise followed by a markedly slower regeneration of PCr during post-exercise recovery parallelled by a slower recovery of pH. This phenomenon was mirrored by a more pronounced decrease of ATP/Pi in patients during exercise and a slower recovery of ATP/Pi. CONCLUSION: The data are compatible with an increased ATP turnover in skeletal muscle cells of patients with untreated primary hypertension although ATP was favoured and kept at a normal resting level at the expense of the PCr store.

Direct effect of insulin on 45calcium uptake in human erythrocytes.

OBJECTIVE: High blood pressure is prevalent in obesity and non-insulin dependent diabetes mellitus; both conditions, with insulin resistance and essential hypertension, have been associated with increasing intra-erythrocytic levels of calcium ions. We tested the hypothesis of whether insulin itself might be responsible for the abnormal red cell cytosolic free calcium. DESIGN: The ionic effects of insulin were studied on the kinetics of 45calcium uptake in vitro in normal human erythrocytes. SETTING: The study was performed in the outpatient clinic of a central hospital. SUBJECTS: Sixteen healthy, normotensive individuals with normal body mass index were recruited for the study. MAIN OUTCOME MEASURES: Blood from eight individuals was used for time-dependent studies of 45calcium uptake in erythrocytes and blood from another eight individuals was used for dose-dependent studies of insulin effect. RESULTS: The rate of 45calcium influx in red blood cells has two components, a fast component (0-10 min), which measures the initial rate of 45calcium influx, and a slow component (10-60 min) probably reflecting a relatively large backflux of calcium (calcium efflux), which accordingly determines an apparent low rate of 45calcium influx between 10-60 min. The uptake was linear with time between 10-120 min regardless of insulin being present or not. Insulin at a concentration of 120 mU L-1 significantly decreased the 45calcium uptake in a time-dependent fashion between 10-120 min. The uptake was 508 (+/- 59) at 60 min in the presence of insulin vs. a control value of 529 (+/- 59) pmol mL red blood cells-1 (P < 0.001). The corresponding figures at 120 min were 742 (+/- 109) and 767 (+/- 127), respectively (P = 0.02). Inconsistent results were obtained on 45calcium uptake at 60 min by varying insulin concentrations from 40-640 mU L-1 and a dual effect of insulin on 45calcium uptake could not be excluded, one at a fairly low concentration of insulin (40-120 mU L-1) and another at a high concentration (160-640 mU L-1). CONCLUSION: The data indicate a direct role of insulin in the transport process of calcium into normal human erythrocytes.

Treatment of renal anaemia with recombinant human erythropoietin results in decreased red cell uptake of 45Ca.

The ability of erythrocytes to undergo deformation may be of importance to erythrocyte survival and to blood flow resistance. In a previous study a decreased deformability was demonstrated in the erythrocytes of uraemic patients treated with recombinant human erythropoietin (rhEPO). Erythrocyte deformability is, at least partly, determined by the intracellular concentration of free calcium ions. Six patients with renal anaemia (initial haemoglobin 95 +/- 11 g/l) were treated with rhEPO. They were examined with regard to certain erythrocyte characteristics before treatment and after reaching a haemoglobin concentration exceeding 120 g/l. A decrease was noted upon treatment in erythrocyte deformability and uptake of 45Ca in vitro. The blood pressure tended to increase. The individual values of the decrease in 45Ca uptake and the increase in systolic blood pressure were positively correlated to each other (r = 0.87; p < 0.05). No correlation was found between changes in erythrocyte deformability and 45Ca uptake. The decrease in 45Ca uptake may be interpreted in two different ways. It could reflect a reduced membrane permeability to calcium ions, or, which is more probable, it could be the end result of an increase in the intracellular metabolic pool of free calcium ions caused by the rhEPO treatment. We, therefore, conclude that rhEPO treatment has certain effects on calcium homeostasis in erythrocytes which may be related to blood pressure regulation.

Decreased erythrocyte cholesterol/phospholipid ratio in untreated patients with essential hypertension.

The erythrocyte cholesterol/phospholipid ratio was determined in eight patients with untreated essential hypertension and compared with that of eight age-matched control subjects. The ratio was significantly lower in patients (Wilcoxon's paired rank test; P less than 0.01), and a correlation existed between the ratio and serum cholesterol concentration in patients (r = 0.63) but not in controls (r = 0.02). A reduction in the cholesterol/phospholipid ratio may play a direct role in destabilizing the plasma membrane, which will in turn result in an increase in membrane permeability in essential hypertension.

Inhibition of Zn(2+)-dependent ATPase in prostasome membrane by nonsaturated, long-chain fatty acids.

Arachidonic and oleic acids, opposite to stearic and palmitic acids, at concentrations near 10(-5) mol/l markedly inhibited Zn(2+)-dependent ATPase in human prostasome membranes. Arachidonic acid was somewhat more potent as inhibitor than oleic acid and the involvement of the metabolites of arachidonic acid cascade was less probable. Deoxycholate, an anionic biological detergent, produced a similar inhibitory effect although at a much higher concentration. The restraining role of nonsaturated, long-chain fatty acids on sperm motility in human semen is discussed in terms of their established inhibitory action on prostasome ATPase systems.

Antianginal and anti-ischemic efficacy of nicorandil compared with nifedipine in patients with angina pectoris and coronary heart disease: a double-blind, randomized, multicenter study.

Patients with stable, effort-induced angina pectoris and a typical combination of anginal pain and ischemic ST depression in exercise tolerance tests were randomized to treatment for 8 weeks with nicorandil (a newly developed antianginal and anti-ischemic drug) or nifedipine. After 4 weeks, the dosage of nicorandil was increased from 10 mg b.i.d. to 20 mg b.i.d., but the recommended dosage of nifedipine, 20 mg b.i.d., was kept constant during the study period. Double-blind treatment was preceded by a 2-week prephase during which patients were treated with isosorbide dinitrate. During the study period, patients were asked to report the rate of anginal attacks and consumption of sublingual nitroglycerin. Measurements of blood pressure and heart rate at rest and during exercise always were performed 2 h after drug intake. Fifty-eight patients were randomized--29 to nicorandil and 29 to nifedipine. There were large individual variations in anginal attack rates, which makes group comparisons difficult, but in the nicorandil group, the anginal attack rate decreased significantly compared with baseline frequency. Systolic blood pressure at rest was reduced significantly only with the highest dose of nicorandil, but nifedipine had a significant effect on both systolic and diastolic blood pressures as well as on the heart rate. Both treatments significantly increased exercise duration, time to onset of angina pectoris, and time to 1-mm ST depression. In the nicorandil group, an improvement was noted with the 20-mg dose compared with the 10-mg dose, but no significant differences were noted between the nicorandil and nifedipine groups after either 4 or 8 weeks of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Phospholipase A activity in seminal plasma of men attending an infertility clinic.

Seminal plasma from 40 men attending an infertility clinic was analyzed for phospholipase A activity and compared with serum from 20 healthy blood donors. The imprecision of the method was acceptable and the overall coefficient of variation was 8.1%. A huge discrepancy existed between seminal plasma and blood serum with regard to phospholipase A activity, the former fluid displaying on average a 180-fold higher activity than the latter. Preincubation of seminal plasma for 1 h at 37 degrees C resulted in an even higher phospholipase A activity while the corresponding activity in serum remained unchanged by such a treatment. This suggested the existence of a zymogen form of phospholipase A in seminal plasma. A significant correlation existed between sperm concentration and phospholipase A activity in seminal plasma (r = 0.46; p less than 0.01) and preincubated seminal plasma samples from normozoospermic men displayed a significantly higher mean value than those of azoospermic men. Phospholipase A activity also correlated significantly to zinc concentration in seminal plasma (r = 0.67; p less than 0.001). 4-Bromophenacyl bromide was inhibitory to a certain extent, the inhibition being most evident in the samples with high phospholipase A activity. Dibucaine and quinacrine, known phospholipase inhibitors in other systems, had no inhibitory effects. Only 58% of the seminal plasma samples contained measurable amounts of triglycerides. No significant correlation existed between triglyceride concentration and phospholipase A activity, r = 0.11.

Increased whole blood viscosity combined with decreased erythrocyte fluidity in untreated patients with essential hypertension.

Erythrocyte fluidity and other haemorheological variables were studied in 22 patients with essential hypertension and compared with age- and sex-matched healthy controls. Hypertensive patients displayed a significantly lower erythrocyte fluidity (P less than 0.001). Similarly, significantly elevated values for haematocrit, plasma and whole blood viscosity, as well as aggregation tendency were observed compared to controls. Although differing in these respects from controls, there were no obvious relationships between these rheological variables and either systolic or diastolic blood pressure. The significantly lower erythrocyte fluidity and other changes in haemorheological variables of red blood cells found in hypertensive patients may be explained by an enlarged metabolic pool of free calcium ions in these red blood cells. It is suggested that the molecular mechanisms underlying the evolution of essential hypertension are multifactorial rather than being based on a single molecular derangement. Primary events resulting in altered physicochemical properties of the red blood cells may work in concert in the development of essential hypertension, in addition to the increased availability of calcium ions and their potential role in smooth muscle contraction.

Improved blood pressure control with isradipine in hypertensive patients treated with pindolol.

Isradipine is a new calcium antagonist of the dihydropyridine type with marked vasodilator activity and minimal negative inotropic effects. It is a potent antihypertensive drug when given as monotherapy. This was a randomized double-blind crossover study of 16 weeks' duration, including 80 hypertensive patients with diastolic blood pressures of at least 95 mm Hg who had shown clinically relevant antihypertensive responses, but no normalization of blood pressure during pindolol 10 to 15 mg once daily as monotherapy. Either isradipine or placebo was added to the beta-blocker at doses of either 2.5 mg or 5 mg twice daily, which was doubled after four weeks if the diastolic blood pressure remained more than 90 mm Hg. The addition of isradipine (in either dose regimen) caused a pronounced reduction of blood pressure with no changes in heart rate. Five patients were withdrawn from the study because of adverse events while receiving isradipine compared with three taking placebo. A further three patients withdrew from the study because of adverse events (one patient) or lack of efficacy (two patients) during placebo treatment. These results indicate that isradipine is an effective and well-tolerated adjunct to beta-blockers in hypertensive patients.

Reversible brain cell damage due to hypoglycemia in a patient with insulinoma.

A case of an insulinoma with hypoglycemic attacks accompanied by episodes of unconsciousness in a 57-year-old woman is described. During the hypoglycemic spells the level of adenylate kinase (AK) in the cerebrospinal fluid (CSF) was elevated 6-fold above the normalized level obtained later from the patient being in a normoglycemic condition. CSF-AK was previously found to be a sensitive marker of subtle brain cell damage due to hypoxia. The increased efflux of AK into CSF during the insulinoma-induced hypoglycemia was most probably the result of a brain cell injury caused by shortage of glycolytic fuel.

Effect of pindolol on changes in serum lipids induced by hydrochlorthiazide.

Forty-two patients with essential hypertension, WHO I-II, and a diastolic blood pressure greater than or equal to 100 mm Hg, were initially given 25 mg hydrochlorthiazide alone. After treatment for 3 months 10 mg pindolol was also given to 16 of them as the diastolic blood pressure had not been reduced to less than or equal to 90 mm Hg. After 3 months treatment on hydrochlorthiazide alone there was a significant increase in serum cholesterol, low density lipoprotein cholesterol and triglyceride concentrations, and a decrease in high density lipoprotein cholesterol concentration, and this pattern persisted after a further 3 months on the single drug regimen. In contrast, in those patients who received additional treatment with pindolol after the first 3 months, there was a significant decrease in the low density lipoprotein cholesterol and an increase in high density lipoprotein cholesterol during the following 3 months. Thus, the addition of pindolol to hydrochlorthiazide therapy appeared to reverse the negative effects on the lipid profile induced by the diuretic alone.

Decreased 45calcium uptake in red cells of patients with essential hypertension.

Decreased 45calcium uptake was observed in red cells of 20 patients with essential hypertension. Equilibration of extracellular 45calcium with intracellular calcium was not achieved within 60 min in red cells of either hypertensive patients or control subjects. By introducing the ionophore A23187, equilibrium conditions were attained for red cells of both categories of individuals. Still the discrepancy in 45calcium uptake was preserved between them. These results support the view that red cells of hypertensive patients have an altered membrane permeability to calcium, possibly reflecting also a greater exchangeable pool of cytosolic free calcium.

Prostasome membrane associated enzyme activities and semen parameters in men attending an infertility clinic.

Seminal plasma from 22 men attending an infertility clinic was subjected to preparative ultracentrifugation for 2 h at 105,000 g. The pelleted material as well as the supernatant thus obtained were investigated with regard to prostasome membrane-linked enzyme activities in relation to other semen parameters. The mean activity of Zn2+-dependent adenosine triphosphatase in the sedimented prostasome fraction was 1.45 +/- 1.02 mumol (range 0.29-4.79) orthophosphate released per milligram protein and 20 min, while the corresponding figures for the supernatant were 0.56 +/- 0.30 (range 0.12-1.29). Hence, 72% of the specific activity was sedimented, and 28% remained in the supernatant. The same pattern was recognized with regard to the other two enzymes investigated, although they displayed individual characteristics with regard to distribution after ultracentrifugation. The pelleted prostasome-linked mean aminopeptidase activity was 0.39 U/mg protein (81.9%), with only 0.087 U (18.1%) remaining in the supernatant. The corresponding figures for gamma-glutamyltransferase were 7.89 (60.4%) and 5.17 (39.6%) mu kat/g protein, respectively. The different enzyme activities in the prostasome fraction and supernatant, respectively, were interrelated to each other and correlated significantly with r values between 0.73 and 0.93 (p less than 0.001). It was concluded that a minor fraction of prostasomes remained in the supernatant after ultracentrifugation. A relationship existed between prostasomes and semen volume revealing a rather consistent pattern in that small volumes favoured the presence of comparatively more prostasomes in the supernatant and less prostasomes in the pelleted fraction than large volumes. In addition, the sperm concentration seemed to be another determinant of the distribution of prostasomes in seminal plasma on subsequent ultracentrifugation.