Polyamines stimulate superoxide production in human neutrophils activated by N-fMet-Leu-Phe but not by phorbol myristate acetate.

The polyamines putrescine, spermidine and spermine, at concentrations of 10 microM, stimulated superoxide generation by human polymorphonuclear leukocytes induced by fMet-Leu-Phe in the presence of Ca2+. This positive effect was not evident in the absence of Ca2+ or when the polymorphonuclear leukocytes were stimulated by phorbol myristate acetate. Spermidine in the range of 10-100 microM showed a dose-dependent stimulatory effect on the superoxide generation induced by fMet-Leu-Phe, whilst at doses above 25 mM it produced an inhibitory effect. At this concentration, spermidine did not reduce the phorbol myristate acetate-neutrophil-induced O2-. generation, while an inhibitory effect by the polyamine was evident at concentrations above 50 mM. In addition, 100 microM spermidine increased the amount of superoxide generated and enhanced the ability of the chemotactic peptide to stimulate superoxide generation. The polyamines in the range of 10 microM-25 mM did not modify the activity of purified NADPH oxidase, nor the rate of reduction of cytochrome c as supported by the xanthine/xanthine oxidase reaction. These results indicate that physiological concentrations of polyamines can stimulate superoxide formation by polymorphonuclear leukocyte cells produced by the chemotactic peptide fMet-Leu-Phe, probably by increasing the availability of external calcium.

Why downfield proton chemical shifts are not reliable aromaticity indicators.

Traces of magnetizability, traces of magnetic shielding at the hydrogen nuclei, and nucleus-independent chemical shift are not reliable aromaticity quantifiers for planar conjugated hydrocarbons. A measure of aromaticity is provided by the out-of-plane tensor components, whose magnitude is influenced by the pi-ring currents. The failure of nucleus-independent chemical shift in this regard was proved for the molecule shown in the abstract graphic, sustaining a diatropic pi-current. The validity of the ring-current model is reaffirmed. [structure: see text]

Ring-current models from the differential Biot-Savart law.

The differential Biot-Savart law provides simple models for the pi ring currents induced in diatropic and paratropic planar conjugated molecules by a perpendicular magnetic field. The model predictions are confirmed by ab initio maps of nuclear magnetic shielding density. The effects on the protons and on the ring carbon atoms from the closest and furthest segments of the current loop are easily interpreted. [structure: see text]

Influence of urine on "in vitro" crystallization rate of calcium oxalate: determination of inhibitory activity by a [14C]oxalate technique.

A simple radiochemical method is proposed for the in vitro assay of the inhibitory activity of urine with respect to calcium oxalate crystal growth using [14C]oxalate as a tracer. The method shows an improved sensitivity over existing methods and indicates that citrate, pyrophosphate and chondroitin sulphate are active inhibitors of calcium oxalate crystal growth down to concentrations of 10(-5), 10(-7) and 10(-10) mol/l respectively. The inhibitory activity in the urines of 12 recurrent calcium stone-formers was significantly lower than in the urines of matched control subjects (P less than 0.01), confirming the clinical usefulness of the test.

Cardiovascular and biochemical assessment in migraine patients submitted to tilt test.

Ten migraine patients underwent a tilt test both during migraine attack and headache-free interval, and the following parameters were assessed: plasma levels of norepinephrine (NE), and serum dopamine beta hydroxylase (D beta H), systolic and diastolic blood pressure and heart rate (SBP, DBP, HR). SBP during the tilt test showed a fall greater than 30 mmHg in 2 cases in the headache-free interval and in 4 cases during migraine attack. In migraine patients in headache-free interval, tilt test increased NE and D beta H as it did in the control group, while in migraine attack tilt test increased NE and D beta H less than in the control group. This impairment of the sympathetic nervous system during the migraine attack is discussed.

Ring current effects on nuclear magnetic shielding of carbon in the benzene molecule.

The differential Biot-Savart law of classical electrodynamics was applied to develop a ring current model for the magnetic shielding of the carbon nucleus in benzene. It is shown that the local effect of the pi currents, induced by a magnetic field normal to the molecular plane, on the sigmaC out-of-plane shielding tensor component vanishes. However, approximately 10% of sigmaC is due to the shielding contributions from pi current density in the region of the other carbon atoms. Magnetic shielding density maps obtained via quantum mechanical procedures confirm the predictions of the classical model.

[Analysis of urinary calculi. Study methods]. / Analisi dei calcoli urinari. Metodi di studio.

A comparative study of the composition of a hundred urinary gravel stones is carried out, made by chemical analysis and spectroscopy infra-red. This research has shown that the spectroscopic method is better than chemical analysis: the latter method is excessively sensitive, above all when considering magnesium, phosphates and uric acid. The marked chemical disclosure of these substances takes us to false conclusions regarding the composition of the gravel stone with percentages varying between 20 and 40% of the cases. On the other hand chemical analysis has not revealed the presence of oxalates in 24% of the gravel stones examined. The spectroscopic method has shown itself to be simpler and faster to execute (a part from being more sensitive and precise), and capable of furnishing precise information on the composition of gravel stones, even very small ones of a weight of 500 microgram.

Spectrophotometric phosphate assay in human seminal plasma. A technique for the determination of glycerol-3-phosphorylcholine secretion.

Glycerol-3-phosphorylcholine (GLY-3-PrC) has a role in determining the epididymal environment, but its function is not yet completely clear. This lack of knowledge might be partially due to the limitations of techniques currently employed in the GLY-3-PrC determination. In this paper we have studied and adjusted to human seminal plasma a spectrophotometric assay initially devised for bull and rabbit ejaculates. By means of column-chromatography and solvent extraction the specific interferences (up to 30%) present in human ejaculate, probably due to phosphatidylcholine, were avoided. The technique is precise, simple, cheap and shows GLY-3-PrC recovery higher than 90%.

[Specific activity and release of norepinephrine in isolated and perfused rabbit hearts under various oxygen pressure]. / Attivita' specifica e rilascio della norepinefrina in cuori di coniglio isolati e perfusi con differenti tensioni di ossigeno.

The incorporation of 3H-tyrosine into norepinephrine of rabbit hearts perfused with Krebs-Henseleit solution containing 11 mM glucose and gassed with 95% O2 - 5% CO2 (control) or 80% O2 - 5% CO2 15% N2 (hypoxic) or 95% N2 - 5% CO2 (anoxic), was studied. In the control hearts a constant specific activity of norepinephrine without any release of catecholamine into coronary effluent was measured after 5, 15, 30, 60 minutes. The hypoxic perfusion while not causing any release of norepinephrine, produced a significant increase in tyrosine incorporation into norepinephrine. The specific activity of norepinephrine and its release into coronary effluent were increased by anoxic perfusion; this effect was most evident when the glucose was replaced with a solution containing 11 mM mannitol. These results suggest that the synthesis of norepinephrine in isolated hearts, lacking of sympathetic innervation, may be affected by different condition of oxygen supply.

Neurovascular island flaps in the emergency reconstruction of the terminal phalanx of the thumb.

The technique of neurovascular island flaps is described applied as an emergency operation in six patients who presented with considerable loss of substance of the fleshy pulp of the thumb or total loss of the terminal phalanx. The writers consider that the reconstructive method described by them is an advance on the traditional method, since not only can the matter be resolved in a single operative session, but epicritic sensitivity is maintained, the length of the thumb remains unaltered, better aesthetic results are obtained, and there are no vasomotor or sympathetic disorders.

Interference of specific autoantibodies in the assessment of serum thyroglobulin.

Prevalence of anti-thyroglobulin autoantibody (anti-TG Ab) above 120 IU/mL was 0.238 in 491 healthy and thyroid-disorder patients (80% female, mean overall age 50 +/- 15 years) presenting to the laboratory for contrastographic, endocrinologic, or general medical purposes. It is well known that anti-TG Ab (autoantibodies to thyroglobulin) can lead to the underestimation of serum thyroglobulin (TG). In this work, recovery (REC) of TG (thyroglobulin) added to the specimen was performed in all TG assays and low REC values were considered indicative of interference. The results show that REC = 70% is a very good cut-off value both for the anti-TG Ab prevalence found in our patients and in all prevalences below 0.6. However, we used an 80% cut-off which shows higher (+11%) sensitivity and in consequence improves the clinical decision. Only 60% of low REC values are directly attributable to high levels of anti-TG Ab. In the remaining 40%, low REC values are associated with low anti-TG Ab (< 120 IU/mL). These data indicate that anti-TG Ab concentrations are not always sufficient for evaluation of interference levels since they do not take account the actual effectiveness of anti-TG Ab. In fact, the same level of anti-TG Ab may reduce REC to different degrees (up to ten times) depending on the source serum. The practical consequence of this marked variability of autoantibody activity is that in the usual double Ab immunoassays REC must be determined for each sample to avoid unsuspected interference and negative influences on the clinical decision.(ABSTRACT TRUNCATED AT 250 WORDS)

[Infrared spectroscopy in the quantitative determination of urinary calculi constituents (author's transl)]. / Analisi quantitativa dei componenti dei calcoli urinari mediante spettroscopia nell'infrarosso.

Infrared spectroscopy of urinary calculi can be used for the quantitative determination of the major constituents in mixed stones; the method is simple and consists in area-measurements of specific absorption peaks of the spectrum of each compound. In the area-measurement method the average error is +/- 2,5% in calcium-oxalate-apatite and +/- 2% in ammonium magnesium phosphate-carboapatite mixtures; within these limits the calculus matrix do not affect significantly the value of areas. An investigation of 64 mixed renal stones shows that in 57% of the samples, apatite is present in the nucleus; uric acid and calcium-oxalate are the most frequent superficial compounds, while the external layer of ammonium magnesium phosphate and the mixture uric acid-calcium phosphate are rare events. In calcium-oxalate-apatite and ammonium magnesium phosphate-carboapatite calculi the quantitative composition of the nucleus and the external layer differ significantly. The proposed method of analysis of internal and external structures in renal calculi can be useful for the study of etiology, for the prevention and the treatment of urolithiasis.

Reduced oxidative activity of circulating neutrophils in patients after myocardial infarction.

Circulating neutrophils isolated from patients 3-4 h after a myocardial infarction produced less O2-. compared with controls, when stimulated with phorbol myristate acetate or formyl-methionine-leucine-phenylalanine. Three days after the infarction the O2-. generation elicited by both stimuli further decreased markedly. Seven and 15 days after infarction the O2-. stimulated production was only slightly lower than or similar to the control values. The neutrophils of infarcted patients showed an augmented latency period before O2-. production compared with controls in response to exogenous stimuli, particularly three days after infarction. Electron microscopy revealed that the neutrophils isolated from the infarcted patients displayed signs of cell exhaustion with few alterations of the plasma membranes when stimulated with phorbol ester. In contrast, control neutrophils displayed alterations of the plasma membranes characteristic of active neutrophils. The results of this study indicate that the circulating neutrophils appear exhausted and functionally inhibited immediately after myocardial infarction.

Reduced cardiovascular responsiveness to exercise-induced sympathoadrenergic stimulation in patients with cirrhosis.

Cardiovascular responsiveness to sympathoadrenergic activation obtained by muscle exercise in the supine position was evaluated in 22 patients with cirrhosis (11 alcoholic, 11 postnecrotic/cryptogenic; 14 with ascites) and 10 controls of comparable age. Plasma norepinephrine, heart rate, diastolic arterial pressure and cardiac function, as evaluated by systolic time intervals, were monitored. At rest, cirrhotics had higher norepinephrine (154 +/- 19 S.E.M. ng/l) and heart rate (79 +/- 2 beats per min) than controls (71 +/- 3 ng/l, p less than 0.01; 67 +/- 2 beats per min, p less than 0.001), whereas diastolic arterial pressure was similar. Among systolic time intervals, electromechanical systole, pre-ejection period, electromechanical delay and pre-ejection period to left ventricular ejection time ratios were prolonged (p less than 0.05 or less). Exercise led to significant increases in plasma norepinephrine, heart rate and diastolic arterial pressure in both controls and patients. In the latter, however, whereas the increase in norepinephrine was greater (p less than 0.001), those in heart rate and diastolic arterial pressure were less (p less than 0.005). As expected, most systolic time intervals shortened, but the decrease in pre-ejection period (p less than 0.05), isometric contraction time (p less than 0.02) and pre-ejection period to left ventricular ejection time ratio (p = 0.06) was less in patients than in controls. Direct correlations between exercise-induced changes in norepinephrine and both diastolic arterial pressure (r = 0.81; p less than 0.005) and heart rate (r = 0.85; p less than 0.002) were observed in controls, while inverse correlations (r = -0.67, p less than 0.001 and r = -0.44; p less than 0.05) were found in cirrhotics. These results suggest that cardiovascular reactivity to the sympathetic drive is impaired in cirrhotics. The impairment of cardiac contractility may be due to altered electromechanical coupling.

Renal function impairment induced by change in posture in patients with cirrhosis and ascites.

The assumption of upright posture by patients with liver cirrhosis leads to striking activation of adrenergic and renin-angiotensin systems. The tilting-induced modifications in renal function of eight healthy controls and 14 untreated patients with liver cirrhosis and ascites were related to plasma concentrations of noradrenaline, renin activity and aldosterone. All patients had preserved renal blood perfusion. All parameters were evaluated during bed rest for two hours and in the sitting posture for one hour. Basal plasma renin activity (0.1 greater than p greater than 0.05), aldosterone and noradrenaline concentrations (p less than or equal to 0.01) were raised in cirrhotics. The renal function tests (creatinine clearance, filtered sodium, tubular rejection fraction, urinary sodium excretion) were significantly reduced in cirrhosis. Under basal conditions, in cirrhotic patients tubular rejection fraction and urinary sodium excretion were inversely related to both noradrenaline and aldosterone concentrations. After tilting, the noradrenaline and aldosterone integrated outputs (sigma delta) were significantly greater in cirrhosis. All renal function tests significantly decreased in cirrhotics, whereas creatinine clearance only significantly decreased in controls. Patient's tubular rejection fraction of sodium and sodium excretion were related to sigma delta aldosteronaemia (r = -0.72; p less than 0.01), but no longer to sigma delta plasma noradrenaline.

Impairment of blood pressure control in patients with liver cirrhosis during tilting: study on adrenergic and renin-angiotensin systems.

Mean arterial pressure, phenylalanine, tyrosine, norepinephrine and plasma renin activity (PRA) were determined in the plasma of 6 healthy controls and 8 patients with liver cirrhosis receiving a controlled sodium intake (40 mEq/day), after 1 h of bed rest and 10 min after being tilted up at 90 degrees. After resting, patients showed lower arterial pressure (p less than 0.025) and higher plasma levels of phenylalanine (p less than 0.005), tyrosine (p less than 0.05), norepinephrine (n.s.) and PRA (n.s.) than controls. In spite of a prolonged and marked stimulation of the adrenergic system induced by tilting, arterial pressure of cirrhotics, after an initial increase, decreased significantly. A significant PRA increase was observed in both groups but in patients it was greater and lasted longer, up to 30 min, when PRA and arterial pressure were inversely and significantly correlated. The adrenergic system of cirrhosis then appeared unable to maintain adequate levels of arterial pressure, even though hyperstimulated. The renin-angiotensin system played an important compensatory role in this contest.

[Catecholamine and renin-angiotensin system in blood pressure control in patients with liver cirrhosis]. / Catecolamine e sistema renina-angiotensina nel controllo della pressione arteriosa in pazienti con cirrosi epatica.

The changes induced by active tilting in arterial pressure, plasma renin activity, norepinephrine and its precursors phenylalanine and tyrosine were evaluated in 8 patients with liver cirrhosis and 6 healthy controls. The results suggest the inability of the adrenergic system, though hyperstimulated, to maintain arterial pressure homeostasis in cirrhosis with a compensatory hyperactive renin-angiotensin system. Derangements in catecholamine synthesis, possibly due to altered utilisation of precursors to alternative final products (weak neurotransmitters?) can be taken into account.

Assessment of cerulein effects on serum bile acids concentration in liver disease. Comparison with the test meal.

Twenty-four liver patients and seven healthy subjects underwent the enzymatic-fluorimetric assay of total serum bile acids during fasting and after a hyperlipidic meal, both alone and with the intramuscular administration of 0.3 microgram/kg of cerulein. A third test with cerulein alone was carried out on the control group and on 12 liver patients. The liver patients were divided into two groups; those with moderate and severe liver disease, according to the degree of liver function impairment and the clinical data. The best discriminant efficiency was observed in the test with the meal alone, even if, in the liver patients, the meal with cerulein caused a greater percentual increase of serum bile acids. After taking into account the most significant correlations between serum bile acids and liver function tests, the addition of cerulein to the meal may be recommended for liver patients with previous cholecystectomy or gallbladder pathology.