Interhemispheric differences of hand muscle representation in human motor cortex

Focal magnetic transcranial stimulation (TCS) is employed for mapping of the motor cortical output to abductor digiti minimi (ADM) muscle. The aim of this study was to evaluate the interhemispheric asymmetries in normals. Motor maps were obtained through motor evoked potentials (MEPs) recordings from ADM muscle in 20 healthy subjects in right and left hemispheres TCS. Measurement of several indexes such as excitability threshold, MEPs amplitude, MEPs latency, and silent period duration did not show differences between the hemispheres. Moreover, no interhemispheric asymmetries were found when the amplitude ratio values were analyzed. The hand motor cortical area, as represented by the number of responsive sites (3.6 vs. 3.5) and the "hot spot" site localization presented a fairly symmetrical organization. Absolute values displayed a relatively wide intersubject variability, while their interhemispheric differences were extremely restricted. This observation can offer a new tool in diagnosing and following up neurological disorders affecting the central motor system, mainly for those concerning monohemispheric lesions.

Mapping of motor cortical reorganization after stroke. A brain stimulation study with focal magnetic pulses

BACKGROUND AND PURPOSE

Focal transcranial magnetic stimulation (TCS) is used for noninvasive and painless mapping of the somatotopical organization of the motor cortex. TCS mapping of motor cortical output to the abductor digiti minimi (ADM) muscle was followed up in monohemispheric stroke patients by evaluating motor evoked potentials (MEPs). This approach allowed noninvasive investigation of the functional reorganization of hand motor areas.

METHODS

Motor maps were constructed for 15 subacute stroke patients about 2 months from the ictus by recording MEPs from the ADM muscle via focal TCS in the affected hemisphere (AH) and unaffected hemisphere (UH) at the beginning of (T1) and after 8 to 10 weeks of neurorehabilitation (T2). Barthel Index and Canadian Neurological Scale scores were evaluated as well. An age-sex matched group of 15 healthy control subjects was enrolled to establish normative data.

RESULTS

MEP excitability threshold was significantly higher in the AH of stroke patients than in normal subjects and in the UH (P < .001); excitability threshold was not significantly different between normal subjects and UH. In the AH, MEPs were significantly (P < .001) delayed in latency both in T1 and T2, with a significant decrease of the extenuation of motor output area to the ADM muscle (P < .05) in T1 versus control group and UH. This area was significantly enlarged (P < .05) in T2. Amplitude of MEPs from the AH, both at rest and during voluntary contraction, was significantly lower than normal in T1 (P < .001); it increased in T2 (P < .01) during relaxation but was still smaller than normal during contraction (P < .001). In combination with these findings, an improvement of Barthel Index and Canadian Neurological Scale scores (P < .001) was observed between T1 and T2 (P < .001). Central conduction time was prolonged in stroke patients both in T1 and T2. Changes in the shape of motor maps in the AH during follow-up in T2 were either isolated (therefore increasing the interhemispheric asymmetry) or also were "mirrored" on the UH.

CONCLUSIONS

Our neurophysiological data are consistent with the presence of a rearrangement of the motor cortical output area and correlate well with an improvement of motor performances. These findings confirm the existence in adults of a "plasticity" in the central nervous system that is still operating between 2 and 4 months from the acute ictal episode. The observed neurophysiological modifications are significantly correlated with clinical improvement of disability and clinical scores.

Toxicity evaluation of waters from a tributary of the River Po using the 7-Day Ceriodaphnia dubia test

Seven-day toxicity tests with Ceriodaphnia dubia were used to assess ambient water toxicity in the River Lambro, a tributary of the River Po, and in the corresponding stretch of the main river located downstream from their confluence. About once a month, toxicity tests were conducted on water samples of the River Lambro, using as dilution water the water of the main river collected upstream from the confluence. With a lower frequency, the downstream stretch of the River Po was tested for ambient toxicity at four sites located at 6, 11, 16, and 21 km from the emission of the tributary. The River Lambro demonstrated variable toxicity in different time periods, although the most frequent effects were sublethal, on both reproduction and growth. Ammonia, nickel, and zinc can be indicated as possible toxicants. Acute toxic effects to C. dubia were observed with spring samples only, when the action of some pesticides, likely insecticides, have to be taken into account. Tests conducted on downstream water gave limited results, seemingly because the dilution capacity of the River Po reduced Lambro toxicity to a level close to and often below the detection limit of the 7-day test. Accordingly, toxic effects at downstream sites could only be observed on the growth of C. dubia, which was found to be the most sensitive endpoint. Fairly good agreement was found between predictions based on toxicity tests of the River Lambro and the effects observed for downstream samples.

Cryoglobulinemia in hepatitis C virus chronic active hepatitis: effects of interferon-alpha therapy

We investigated the prevalence of mixed cryoglobulinemia (MC) in 100 cases of chronic hepatitis C virus (HCV) infection and the effect of a 6-month treatment with interferon-alpha (IFN-alpha). Cryoglobulins were detected on admission in 36 of 100 patients and appeared during observation in a further 18 cases. Cryocrit ranged from 0.5% to 20%. Patients with MC were older and had a higher incidence of cirrhosis than those without MC. Immunologic characterization of the cryoprecipitate showed the presence of type II in 84% of cases and type III in 16%. The patients received IFN-alpha (6 MU three times per week) for 6 months. Fifty-seven were responders (i.e., reached normal aminotransferase levels), 26 of these relapsed within 2 months after IFN withdrawal, and 30 did not relapse. After IFN-alpha treatment, cryoglobulinemia disappeared in 11 of the 21 evaluable responders, but in none of the 15 nonresponder patients (p < 0.003). The clearance of MC was associated in all cases with clearance of HCV RNA. The delayed appearance of cryoglobulinemia in responders seems to be associated with a higher probability of relapse.

The dyspeptic syndrome in migraine: morphofunctional evaluation on 53 patients

The authors, in order to evaluate the important role of gastrointestinal dysfunction during the migraine attack, have studied 53 patients with migraine without aura during the asymptomatic stage between attacks. Patients were examined functionally with a pH meter test of the gastroesophageal tract over 24 hours and morphologically with esophagogastroduodenoscopy. The results of this study point out that in a high percentage of patients with migraine, both evaluations are normal. The authors suggest the possibility of detecting, even hypothetically, an alteration of the common neurotransmitter substrate in the origin of migraine attacks and accompanying symptoms.

Use of high sumatriptan dosages during episodic cluster headache: three clinical cases

The authors describe three patients with episodic cluster headache whose attacks were all treated with subcutaneous sumatriptan. The patients described had a high frequency of attacks (more than two per day); therefore, far higher dosage of the drug was taken than commonly used in cluster headache. The patients did not experience any particular side effects, neither during the treatment period nor on abrupt withdrawal of the drug. Moreover, neither tachyphylaxis nor addiction were observed. The authors point out both the efficacy of sumatriptan, confirmed in all the treated attacks, and its safety even at higher dosages than recommended.

Short-term diabetic ketosis alters n-6 polyunsaturated fatty acid content in plasma phospholipids

At present, no information is available about the possibility that acute loss of metabolic control might be able to modify fatty acid composition in IDDM patients. Therefore, the aim of this study was to determine whether a short-term period of ketosis has any effect on the composition of fatty acid of plasma phospholipids in a group of insulin-dependent diabetes mellitus (IDDM) patients. Eleven IDDM patients and nine healthy volunteers were studied. Patients were studied over a 2-day period; each 2-day period consisted of initial baseline measurements followed by a day of hyperglycemia and mild ketosis, which was promptly alleviated by insulin infusion. No significant difference in baseline percent fatty acid composition was observed between normal controls and IDDM patients. In IDDM patients, ketosis induced a significant decrease in percent arachidonic acid (20:4 n-6) content, with a significant parallel decline in n-6 total polyunsaturated fatty acids. A significant inverse correlation between the prevailing plasma glucose and the relative content of arachidonic acid in plasma phospholipids was observed (r = -0.35; P = 0.0488). A highly significant inverse correlation was observed between the change from baseline condition to ketosis of the ratio C20:4/C20:3, the product/precursor ratio for the reaction catalyzed by delta5-desaturase, and the values of hemoglobin A1c,(r = -0.855; P = 0.0015). In conclusion, short term diabetic ketosis is associated with a significant decrease in n-6 polyunsaturated fatty acid content in plasma phospholipids, especially arachidonic acid. This decrease in arachidonic acid appears to be related to the degree of metabolic derangement, whereas the influence of short-term diabetic ketosis on the ratio of C20:4 to C20:3 seems to be due to the degree of long-term metabolic control.

Anomalous phospholipid n-6 polyunsaturated fatty acid composition in idiopathic calcium nephrolithiasis

Anomalies in the erythrocyte transport of anions and cations have been described in idiopathic calcium oxalate nephrolithiasis and seem to play a pathogenetic role in this disease. In consideration of the hypothesis that the complex array of ion flux cell abnormalities is an epiphenomenon of an anomaly in the composition of cell membranes, this study investigated cell-membrane lipid composition. In idiopathic calcium oxalate renal stone formers, in which ion transport abnormalities were present, and in healthy control subjects, plasma and erythrocyte membrane lipid composition, the erythrocyte oxalate exchange, and Na/K/2Cl cotransport activity were evaluated. Furthermore, in stone formers, the effect of a 30-day fish-oil diet supplementation on plasma lipids, erythrocyte oxalate exchange, oxaluria, and calciuria was investigated. The effect of archidonic acid released by phospholipase A2 on anion-carrier phosphorylation and activity in erythrocytes was evaluated as well. Patients had a lower content of linoleic and higher concentration of archidonic acids in both plasma and erythrocyte membrane phospholipids, and an increased archidonic/linoleic acid ratio. The archidonic acid level correlated with the erythrocyte oxalate exchange and sodium cotransport activity. Fish-oil supplementation lowered calcium and oxalate urine excretion, and normalized the erythrocyte oxalate exchange. Phospholipase A2 increased the erythrocyte anion-carrier protein phosphorylation and the oxalate exchange. This study shows that idiopathic calcium nephrolithiasis in the patient group reported here is characterized by a systemic defect in phospholipid archidonic acid levels that might provide an answer to the link between genetic background, dietary habits, and renal lithiasis.

Influences of lipid and non-lipid nutritional parameters on factor VII coagulant activity in normal subjects: the Nove study

Community-based studies have suggested that the dietary intake of total fat influences factor VII coagulant activity (FVIIc), a predictor of fatal events from coronary heart disease (CHD). Nevertheless, the question whether the quality of dietary fats, with special reference to fatty acids (FAs), influences FVIIc is unsolved. The authors investigated in 90 healthy volunteers living in Nove, a village near Vicenza (northern Italy), the relationships between FVIIc and the plasma concentration of individual FAs. Several indices of other nutritional factors that have recently received increasing attention as determinants of CHD risk (antioxidant vitamins A and E, oligoelements) were also included in the multivariate analysis. The stepwise multiple linear regression analysis revealed body mass index (BMI), and the concentrations of plasma stearic acid (C18:0) and serum copper as significant independent predictors of a substantial proportion of FVIIc variability (R = 0 center dot 52; R2 = 0 center dot 27; P < 0 center dot 001). This study substantially supports the role of the plasma concentration of stearic acid as an important factor in modulating FVIIc.

[Assessment of complications of major orthopedic surgery: comparison of indobufen, calcium heparin, and low molecular heparin]

OBJECTIVE

Evaluation of incidence of postoperative thrombotic and haemorrhagic complications in autotrasfused patients undergoing blood predepositing, hemodilution, intra and postoperative blood saving and treated with indobufen, heparin calcine and low molecular weight heparin (enoxeparin).

EXPERIMENTAL DESIGN

Comparative study. Length of follow up: 6 months.

SETTING

Three division of Orthopaedic Surgery related to 1st Anaesthesiology and Intensive Care Unit of Rizzoli Orthopaedic Institute.

PATIENTS

980 consecutive patients admitted to hospital from 1-1-1992 to 30-6-1994 (321 males and 159 females), aged between 20 and 90 years (mean 62 +/- 11 years), with basal hemoglobin at 13.4 +/- 1.4 g/dI (range 6.7-17.9), who had undergone antithromboembolic prophylaxis with indobufen (Indo, 668), heparin calcine (CaHe, 200) and low molecular weight heparin (LMWH).

INTERVENTIONS

Total hip (714) and knee (121) arthroprosthesis and hip replacements (cup 33, stem 10, cup and stem 102).

MEASUREMENTS

The incidence of death, thromboembolic complications (pulmonary embolism, deep vein thrombosis), hemorrhage (hematoma and homologous transfusions), cardiac ischaemia. ANOVA and contingency tables (CT) were used for statistical.

RESULTS

The absence of complications was significantly greater in patients treated with indobufen (Indo 94.3% vs CaHe 83.5% vs LMWH 85.7%, CT: p = 0.0001); the incidence of thromboembolic complications was significantly higher in patients treated with heparin calcine and low molecular weight heparin; in patients treated with heparin calcine the incidence of haemorrhagic complications was significantly higher. Due to bleeding brought about by the use of heparin calcine, one patient with coronary heart disease suffered from anemia and severe hypotensions by myocardiac infarction and cardiogenous shock which led to the patient's death. The use of homologous transfusions was significantly higher in patients treated with heparin calcine (Indo 4.2% vs CaHe 14.5% vs LMWH 4.5%, CT: p = 0.0001).

CONCLUSIONS

In patients undergoing autotransfusion and hemodilution, indobufen has a lower of haemorrhagic complications compared to heparine calcine and low molecular weight heparin and it is more effective in the prevention of thrombotic complications at clinical evidence.

Selenium, zinc, and thyroid hormones in healthy subjects: low T3/T4 ratio in the elderly is related to impaired selenium status

Iodothyronine 5' deiodinase, which is mainly responsible for peripheral T3 production, has recently been demonstrated to be a selenium (Se)-containing enzyme. The structure of nuclear thyroid hormone receptors contains Zinc (Zn) ions, crucial for the functional properties of the protein. In the elderly, reduced peripheral conversion of T4 to T3 with a lower T3/T4 ratio and overt hypothyroidism are frequently observed. We measured serum Se and RBC GSH-Px (as indices of Se status), circulating and RBC Zinc (as indices of Zn status), thyroid hormones and TSH in 109 healthy euthyroid subjects (52 women, 57 men), carefully selected to avoid abnormally low thyroid hormone levels induced by acute or chronic diseases or calorie restriction. The subjects were subdivided into three age groups. To avoid under- or malnutrition conditions, dietary records were obtained for a sample of 24 subjects, randomly selected and representative of the whole population for age and sex. Low T3/T4 ratios and reduced Se and RBC GSH-Px activity were observed only in the older group. A highly significant linear correlation between the T3/T4 ratio and indices of Se status was observed in the older group of subjects (r = 0.54; p < 0.002, for Se; r = 0.50; p < 0.002, for RBC GSH-Px). Indices of Zn status did not correlate with thyroid hormones, but RBC Zn was decreased in older as compared with younger subjects. We concluded that reduced peripheral T4 conversion is related to impaired Se status in the elderly.

Role of the Na(+)-Ca2+ and Na(+)-H+ antiporters in prolactin release from anterior pituitary cells in primary culture

2',4'-dimethylbenzamilamiloride (DMB), a somewhat selective inhibitor of the Na(+)-Ca2+ exchanger, in concentrations of 10, 30 and 100 microM did not produce any significant effect on baseline prolactin release from anterior pituitary cells in primary culture. When prolactin secretion was stimulated by the inhibitor of the Na(+)-K(+)-ATPase, ouabain, that activates the Na(+)-Ca2+ exchanger as a Ca(2+)-influx pathway, DMB was able to produce inhibition of prolactin secretion. 5-(N,N-hexamethylene) amiloride (HMA), another amiloride analog which specifically inhibits the Na(+)-H+ antiporter and has no inhibitory activity on the Na(+)-Ca2+ exchanger, at the concentrations of 0.1, 1 and 10 microM, did not affect basal prolactin release whereas it significantly reduced prolactin release stimulated by thyrotropin releasing hormone (TRH) (1 microM). These results suggest that the Na(+)-Ca2+ antiporter is involved in the process of prolactin release elicited by the inhibition of the Na(+)-K(+)-ATPase whereas the Na(+)-H+ antiporter is involved in the prolactin secretion elicited by TRH.

Systemic passive transfer studies using IgM monoclonal antibodies to sulfatide

We present a patient with benign IgM-gamma anti-Sulfatide (SUL) whose neuropathy was transferred in newborn rabbits. The patient's clinico-pathological picture of anti-SUL-associated demyelinating neuropathy is reported. The monoclonal IgM antibodies prepared by Tatum's method, that retained their biological activity, were passively transferred to newborn rabbits. The passive transfer produced demyelinating nerve lesions very similar to the donor antibody neuropathy. In experimental lesions we observed the human IgM anti-SUL antibodies binding to Schmidt-Lanterman incisures and nodes of Ranvier. We postulate that the myelin-specific and complement-dependent lesions observed in the peripheral nerve support the potential demyelinating role of anti-SUL antibodies. Moreover, the pattern of the antibody binding to the perineuronal sheath of satellite cells in dorsal root ganglia strengthen the hypothesis that anti-SUL antibodies may have a pathogenetic role in this sensorimotor syndrome.

Directional coronary atherectomy and progressive coronary dilatation: a comparative analysis of acute outcome

To evaluate the acute results and in-hospital complications of directional atherectomy (DCA) as compared to progressive coronary dilatation (PCD), we retrospectively analyzed the acute outcome of DCA with PCD in age-, sex-, vessel-, and lesion morphology-matched groups of patients during the same time span. There was a total of 73 matched patients (77 lesions) in each group. Angiographic success on the basis of intent to treat was 85% in the DCA cohort versus 97%. The preprocedural mean diameter stenosis was similar between the two groups (87% vs 84%; p = n.s.). The mean postprocedural stenosis was significantly lower with DCA than with PCD (11.2% vs 19.7%; p < or = 0.05). Complications including death, myocardial infarction, and need for emergency bypass surgery were not statistically different in either group. In conclusion, PCD offers an alternative method of coronary intervention in patients with "atherectomy anatomy" with a significantly higher success rate. It can also be used successfully when DCA fails or cannot be performed because of technical factors.

[Evaluation of the efficacy of oral sumatriptan in the management of migraine attacks. Clinical results]

This italian multicentre, double blind, parallel groups study compared the efficacy, safety and tolerability of oral sumatriptan, given as new film-coated tablet, with placebo in the acute treatment of migraine. 88 Patients received placebo and 162 patients received sumatriptan 100 mg (plus an optional dose 2 h later if the headache persisted plus a further optional dose for recurrence within 24 h). Sumatriptan was significantly more effective than placebo at releiving headache at 2 h (51% versus 31%, P = 0.003) and 4 h (71% versus 35%, P < 0.001). Fewer sumatriptan-treated patients required a second dose compared with placebo-treated patients (49% versus 74%, P < 0.001). Sumatriptan was more effective than placebo at relieving nausea, vomiting and photophobia/phonophobia. Few patients were evaluable for treatment of headache recurrence, and statistical analysis was not possible. More sumatriptan-treated patients than placebo-treated patients reported adverse events (29% versus 16%) but the difference was not statistically significant. More of these events were mild to moderate in severity, of short duration and resolved without treatment. Sumatriptan had no clinically significant effect on blood pressure, heart rate, electrocardiogram or laboratory test results. It is concluded that oral sumatriptan 100 mg, given as a film-coated, tablet, provides an effective and well-tolerated acute treatment for migraine.

Physico-chemical properties of membranes of recovered erythrocytes in blood autologous transfusion: a study using fluorescence technique

Using fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) and its derivative trimethylammonium-1,6-diphenyl-1,3,5-hexatriene (TMA-DPH), we have investigated the fluidity in erythrocyte membranes isolated from intraoperatively and postoperatively recovered erythrocytes, compared to membranes isolated from untreated erythrocytes or stored red blood cells (RBCs). Fluorescence polarization (Pf) of DPH and TMA-DPH was not significantly modified in membranes isolated from intraoperatively and postoperatively recovered RBCs compared to membranes isolated from untreated fresh RBCs or stored RBCs. However, using 2-dimethyl-amino-6-lauroyl-naphtalene (Laurdan), a very sensitive molecule, a significant increase in polarity in membranes from stored RBCs compared to untreated, intraoperatively and postoperatively recovered RBCs was observed. Moreover, there was significantly higher susceptibility to oxidative stress in membranes isolated from stored RBCs, compared to untreated and intraoperatively or postoperatively recovered RBC membranes, both at baseline and after oxidative stress. Our results suggest that intraoperative and postoperative recovered RBCs are less damaged than stored RBCs.

The lipoprotein composition of plasma and ascitic fluid in liver cirrhosis

Lipoprotein particles were examined in plasma and ascitic fluid from nine patients (5 males and 4 females) with liver cirrhosis and in plasma from nine control subjects. LDL and HDL fractions were isolated by ultracentrifugation under rate flotation conditions in a zonal rotor. LDL size was analysed by non-denaturing polyacrylamide gradient gel electrophoresis. Plasma lipids in cirrhotic patients were markedly reduced compared to controls. Free cholesterol represented 45.3% of the total cholesterol in plasma and 70.4% of the total cholesterol in the ascitic fluid. The total cholesterol-triglyceride ratio was three times higher in the plasma than in the ascitic fluid of cirrhotic patients. The LDL particles had the same flotation properties in plasma from cirrhotic patients as in that from controls. In cirrhotic patients the IDL concentration was higher than that in controls. In ascitic fluid the LDL particles had a higher flotation rate than in the plasma. The LDL diameter as measured by gradient gel electrophoresis was similar in both plasma and ascitic fluid of the cirrhotic patients as well as in the plasma of controls. In plasma and ascitic fluid of cirrhotic patients only a single HDL subclass (HDL1) could be identified. HDL1 particles had a higher flotation rate than normal HDL particles. The plasma levels of all the apoproteins were reduced in cirrhotic subjects compared to controls, but to a variable degree; while apo CII level in cirrhosis represented only 9% of the control level, the apo E level represented 77% of the control level.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood saving program: a multicenter Italian experience

To assess the causes of failure in a blood saving program and the consequent need for homologous transfusions during major orthopedic surgery, data were collected from six orthopedic centers where an autotransfusion program was carried out from 1992-1994. The 1,576 (1,016 female and 560 male) patients studied (average age 63.6 +/- 10 years) were treated either for total hip prosthesis (1,144 pts) total knee prosthesis (212 pts), plate and screw removal plus hip prosthesis (8 pts), hip revision (cup 48 pts, stem 10 pts, cup plus stem 146 pts) and total knee revision (8 pts). Ninety percent of patients did not undergo homologous transfusions, which was significantly connected to: male sex (8% versus 11.7% p = 0.02), younger age (63.2 vs 66.9 years, p = 0.0001), higher weight (male 76 vs 70.7 Kg. p = 0.003, female 65.6 vs 61.9 Kg. p = 0.0003); higher baseline Hb (13.9 vs 12.8 g/dl, p = 0.0041), shorter operation time (110 vs 128 minutes, p = 0.0001); use of indobufen for antithromboembolic prophylaxis (indobufen 4.6% vs heparin calcium 15.2% vs low molecular weight heparin 9% p = 0.0001). On the contrary, the factors favoring homologous transfusions were: peripheral anesthesia (spinal and epidural 15.3% vs general 9.3% vs integrated 9.8% p = 0.016), total hip or knee revision, fixation device removal before hip prosthesis, systemic hypertension and coronary heart disease.

Anaesthesia and autologous transfusion

The anaesthesiologist plays a central role in co-ordinating the combined application of the various blood saving techniques. In fact, to carry out transfusion therapy correctly, the anaesthesiologist must plan the right number of units of predeposit blood during the first examination, estimate the salvage of intra and post operative blood loss and spread the infusion of the units over the first three days in order to keep the patient in a state of haemodilution. From January 1992 to June 1994 in the department of anaesthesia and the intensive care unit, 980 patients were treated for total joint replacement: 714 total hips (7 after removal of plates and screws) 145 revisions, and 121 total knee prostheses. Basal Hb was 13.4 +/- 1.4 g/dl (range 6.7-17.9 g/dl). Homologous transfusions were carried out in 6.3% of these patients. The need to use homologous transfusions was negatively influenced by female sex, coronary heart disease (p = 0.005), length of surgery and type of antithromboembolic prophylaxis (indobufen has a significantly low incidence-p = 0.0001--compared to calcium heparin or low molecular weight heparin).

Erythrocyte Na(+)-H+ exchanger and Na(+)-Li+ countertransport activity in primary aldosteronism

Several authors have described increased Na-H exchanger activity in essential hypertension but no data are available in secondary forms of hypertension such as primary aldosteronism. We measured Na-H exchanger kinetics together with Na-Li countertransport Vmax in the erythrocytes of eight patients with primary aldosteronism and in 15 normotensive control subjects. Plasma aldosterone, plasma renin and plasma potassium were also evaluated. Na-H exchanger Vmax appear to be increased in patients with primary aldosteronism and Hill's n, an index of co-operativity amongst intracellular proton binding sites, was significantly lower in patients than in controls. No statistically significant differences were found between affinity for intracellular protons (K50%) and for Na-Li countertransport Vmax between the two groups studied. We were unable to find any correlations between Na-H exchanger Vmax and Na-Li countertransport Vmax in the two groups considered as a whole. From the present data Na-H exchanger overactivity would not appear to be a specific feature of essential hypertension but seems to be characteristic in patients with primary aldosteronism.

Appearance of depolarization- and maitotoxin-induced [Ca2+]i elevation in single LAN-1 human neuroblastoma cells on exposure to retinoic acid

LAN-1 is a human neuroblastoma cell line that, in the undifferentiated state, does not respond to membrane depolarization with an elevation of [Ca2+]i, monitored by fura-2 single-cell microfluorimetry. The exposure of LAN-1 cells to the differentiating agent retinoic acid induced the appearance of [Ca2+]i elevation elicited by 55 mM K+. Maitotoxin, a putative activator of voltage-sensitive Ca2+ channels, did not evoke an elevation of [Ca2+]i in undifferentiated LAN-1 cells, but produced a marked and sustained increase in [Ca2+]i when superfused in retinoic acid-treated cells. Both high K(+)- and maitotoxin-induced [Ca2+]i elevation in retinoic acid-differentiated LAN-1 cells was reversed by the lanthanide Gd3+, an inorganic Ca(2+)-entry blocker, and by the snail toxin omega-conotoxin GVIA, which interacts with the N subtype of voltage-sensitive Ca2+ channels. In contrast, both Bay K 8644 and nimodipine, dihydropyridines that selectively activate or block, respectively, the L-channel subtype, were completely ineffective. The tumor promoter phorbol 12-myristate 13-acetate (100 nM), a protein kinase C activator, inhibited the elevation of [Ca2+]i due to Ca2+ influx elicited by membrane depolarization. K(+)-induced [Ca2+]i elevation appeared 24 h after the addition of retinoic acid and reached the highest magnitude after 72 h. Furthermore, 8 days after the removal of the differentiating agent from the culture medium, the high K(+)-induced increase of [Ca2+]i was still present.(ABSTRACT TRUNCATED AT 250 WORDS)

Methods of blood saving in revision surgery of the hip

The blood saving protocol, which is the product of 15 years of experience, has gradually been improved, until the current form has been achieved, which includes predeposit, acute intentional isovolemic hemodilution, controlled hypotension, intraoperative blood recovery, postoperative monitoring and blood recovery, external compressive elastic dressing. The acceptance of values for hemoglobin which may even be < 8 g/dl during the late postoperative period, as long as this is well-tolerated by patients, has allowed us to drastically reduce the use of homologous transfusions. Over the last 2 years, out of 59 autotransfused patients submitted to revision surgery of the hip, only 9 (equal to 15%) required homologous transfusion. An analysis of the data shows that the use of homologous blood is associated with the presence of ischemic cardiopathy (p < 0.001) and with a predeposit which is less than 4 units of blood (packed red blood cell+fresh frozen plasma) (p = 0.05).

Relationship between time of activation of phospholipase C-linked plasma membrane receptors and reloading of intracellular Ca2+ stores in LAN-1 human neuroblastoma cells

The effect of sequential stimulation of different inositol (1,4,5)-trisphosphate (IP3)-linked receptors on the functioning of intracellular Ca2+ stores was evaluated in single LAN-1 human neuroblastoma cells by means of fura-2 microfluorimetry. Homologous restimulation both in the absence and in the presence of extracellular Ca2+ with endothelin-1 (ET-1), Lys-bradykinin (BK), and ATP did not elicit an intracellular Ca2+ increase, whereas a [Ca2+]i elevation after carbachol (CCh) re-exposure was obtained only in the presence of extracellular Ca2+. Since thapsigargin and ionomycin, in the absence of extracellular Ca2+, were still able to release Ca2+ after ET-1, BK, and ATP but not after CCh, it can be argued that in the first case the stores were not completely depleted. This evidence was also confirmed by the fact that LAN-1 cells, sequentially exposed in different order to ET-1, BK, ATP, and upon extracellular Ca2+ removal, showed an increase of [Ca2+]i although progressively reduced in magnitude. By contrast, when CCh was perfused as the first agonist, it completely precluded any further Ca2+ mobilization by the other three agonists. In addition, the lack of potentiation of the Ca2+ response when BK and ET-1 were superfused together and the potentiation of Ca2+ response elicited by ET-1 after BK, when the plasma membrane Ca2+ efflux pathways were blocked by lanthanum during the first agonist exposure, indicated that LAN-1 cells can recycle cytoplasmic Ca2+ when exposed to ET-1, BK, ATP but not when exposed to CCh. This inhibitory effect of CCh (perfused for 90 s) on Ca2+ refilling was strictly dependent on the time of receptor occupancy since the exposure to CCh for a shorter period (15 s) produced the same effect on Ca2+ refilling when ET-1, BK, and ATP were perfused, as first agonist, for 90 s. Furthermore, the entity of Ca2+ refilling after 15 s of BK receptor occupancy was similar to that observed after 90 s. This seems to suggest that the receptors for ET-1, BK, and ATP maintain the transductional mechanisms in an activated state for a time shorter than the time of receptor occupancy. This was confirmed by the fact that IP3 levels during a 90-s BK exposure fell to prestimulated value within 30 s, whereas after CCh they reached a sustained plateau phase, after the peak.

Factors affecting the thiobarbituric acid test as index of red blood cell susceptibility to lipid peroxidation: a multivariate analysis

The relationship between formation of thiobarbituric acid reactive substances (TBARS) in red blood cells (RBC) after exposure to H2O2 and factors potentially able to modulate it was investigated by a multivariate analysis in 92 healthy volunteers. The independent covariates considered were: RBC membrane fatty acids and cholesterol, RBC antioxidant enzymes and zinc, plasma vitamins A and E and serum selenium, zinc and copper. The stepwise multiple-linear-regression analysis revealed RBC membrane fatty acids and cholesterol as predictors of a consistent proportion of the RBC-TBARS variability whereas none of the antioxidants entered the equation. The unsaturation index was the most important individual predictor; RBC-TBARS increased with increasing concentrations of total omega-3 polyunsaturated fatty acids, C 20:5 omega-3 and cholesterol, whereas they decreased with increasing concentrations of total monounsaturated fatty acids, saturated fatty acids, C 16:0 and C 18:0. It is suggested that formation of TBARS, at least in currently used conditions, reflects mainly the lipid composition of the tissue under investigation, without giving sufficient information about the status of the antioxidant defences.

Decreased activity of scavenger enzymes in human hepatocellular carcinoma, but not in liver metastases

To investigate the role of oxygen free radicals in hepatocellular carcinoma we assayed tissue scavenger enzymes (superoxide dismutase and selenium-dependent glutathione peroxidase) in liver homogenate, plasma concentrations of vitamins A and E and the serum selenium level from 19 control patients, 23 cases of hepatocellular carcinoma and 18 cases of metastases to liver from different carcinomas. In hepatocellular carcinoma tissue the enzyme activities were all significantly lower than in control liver and in metastases-bearing liver; the enzyme activities of the latter tissues were not different from control liver. In contrast, normal liver adjacent to the hepatocellular carcinoma had decreased activity of superoxide dismutase. Serum selenium concentrations were significantly decreased in patients with hepatocellular carcinoma and those with liver metastases, while vitamin A was significantly decreased only in the former. These findings suggest that hepatocellular carcinoma develops in liver with severe impairment of cellular antioxidant systems, since, in patients with liver metastases from different cancers, despite low selenium concentrations, cellular scavenger enzymes have normal activities.