Neuropsychological assessment in schoolchildren from an area of moderate iodine deficiency

Neuropsychological assessment was carried out in schoolchildren from a montane area of Eastern Tuscany (Tiberina Valley). This area was found to be moderately iodine deficient (mean urinary iodine excretion: 39 micrograms/g creatinine), with a cumulative goiter prevalence of 51.9% in schoolchildren aged 6-14 yr (goiter prevalence in the control iodine-sufficient area: 5.6%). No significant differences in serum TT4, TT3, FT4I, TSH levels between the endemic and control areas were found, whereas serum thyroglobulin values were significantly higher in the iodine-deficient area (61 +/- 8 vs 17 +/- 1 ng/ml, p less than 0.01). No differences were found as to the height, body weight and pubertal development in the two areas. Neuropsychological assessment, performed in a representative sample of 50 schoolchildren from the endemic area and 50 schoolchildren from the control area, matched for age, sex and socioeconomical conditions, failed to show major differences between the two groups in the global neuropsychological performance and cognitive levels. However, minor but significant differences were noted in the information vocabulary and coding subtests, at least in children aged 8. Although familial cultural influences might play a role, it would appear that some marginal impairment, with particular regard to motor-perceptual functions, be present in areas of moderate iodine deficiency.

Diacetylrhein and rhein: in vivo and in vitro effect on lymphocyte membrane fluidity

The effect of diacetylrhein on lymphocyte membrane fluidity in osteoarthritis patients before and after 10 and 30 days of treatment was studied using the 1,6-diphenyl-1,3,5-hexatriene fluorescence polarization. Moreover we studied the in vitro effect of rhein, the active metabolite of diacetylrhein, on lymphocyte membrane fluidity of controls using the fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene and its cationic derivative 1-(4-trimethylaminophenyl)-6-phenyl-1,3,5-hexatriene. Our results showed that the patients with active osteoarthritis have higher fluorescence polarization values than those in the other osteoarthritis patients and in the controls. Moreover after 10 days of diacetylrhein treatment, we observed a significant decrease of fluorescence polarization values only in lymphocytes of the patients who showed active osteoarthritis before therapy. However after 30 days of treatment, significant changes of fluorescence polarization values were observed also in those patients who did not show painful osteoarthritis before diacetylrhein treatment. We observed that in vitro rhein also induces an increase in lymphocyte membrane fluidity, more evident with 1-(4-trimethylaminophenyl)-6-phenyl-1,3,5-hexatriene with respect to 1,6-diphenyl-1,3,5-hexatriene.

Factors limiting maximal oxygen consumption in humans

The factors limiting VO2max in humans are analyzed according to a multifactorial model derived from the O2 conductance equation. In this context, alveolar ventilation (VA) and lung O2 transfer (GL) are not considered to be limiting, at least at sea level, because changes in VA and/or in GL are not accompanied by changes in VO2max due to the shape of the O2 dissociation curve. Thus, the limits to VO2max are shared between blood O2 transport (FQ') and a peripheral factor. This last includes tissue O2 transfer (Ft') and mitochondrial O2 utilization (Fm'). In untrained subjects at sea level, blood O2 transport is found to be responsible for approximately 70% of the overall limits to VO2max (FQ' = 0.7), the rest depending on the peripheral factors. FQ', as well as the sum of Ft' and Fm', are unchanged after training or upon return to sea level following exposure to chronic hypoxia (altitude higher than 5000 m). In the latter condition, however, since tissue O2 transfer, which sets Ft', is facilitated, and mitochondrial O2 utilization, which sets Fm', is impaired, Ft' is reduced and Fm' increased as compared to control condition and/or after training.

Evidence that plasma membrane fluidity of isolated hepatocytes is modified by exposure to microtubule-depolymerizing drugs

The role of microtubules on membrane fluidity has been investigated on freshly isolated whole rat hepatocytes prepared by the perfusion method and exposed either to the microtubule-depolymerizing drugs colchicine and vincristine or to beta-lumicolchicine, a colchicine analog deprived of biological activity. Exposure of hepatocytes to 6.3 microM colchicine or to 3.0 microM vincristine led to a significant decrease of membrane fluidity as measured by fluorescence polarization of trimethylammoniodiphenylhexatriene (TMA-DPH). No changes were observed in cells exposed to 10.0 microM beta-lumicolchicine. These observations support the hypothesis that the microtubular system plays a role in the modulations of physico-chemical properties of the plasma membrane.

Oxygen transport system before and after exposure to chronic hypoxia

Maximal VO2 on the treadmill (VO2max) and on the bicycle ergometer (VO2peak), maximal cardiac output (Qmax), by a CO2 rebreathing method, maximal heart rate (HRmax), blood hemoglobin concentration (Hb), and hematocrit (Hct) were measured on six subjects before (B) and 3 weeks after (A) prolonged exposure to chronic hypoxia. It was observed that after high-altitude exposure VO2max, VO2peak, and Qmax were lower (P less than 005) than before [A: 4.13 +/- 0.67; 3.28 +/- 0.41 and 16.89 +/- 2.49 (l/min +/- SD); B: 4.39 +/- 0.39; 3.53 +/- 0.34 and 21.81 +/- 1.27, respectively], whereas Hb and Hct were larger (A: 162 +/- 8 g/l and 0.46 +/- 0.02; B: 142 +/- 7 and 0.41 +/- 0.02) and HRmax was unchanged (178 +/- 7 vs 175 +/- 9 bts/min). Thus, the calculated stroke volume of the heart and the Hb flow at VO2 peak were lower in A than in B (95 +/- 15 vs 124 +/- 7 ml and 2,723 +/- 307 vs 3,129 +/- 196 g/min) (P less than 0.05, respectively), whereas the arteriovenous O2 difference was greater in A than in B (195 +/- 16 vs 162 +/- 19 ml O2/l; P less than 0.05). At any given submaximal work load, VO2 and HR were the same in B and in A, whereas Q was lower in A by approximately 2-3 l/min. However, because of the increased Hb, leading to a higher arterial O2 content, at any work load the O2 flow remained unchanged.

Maximal muscular power before and after exposure to chronic hypoxia

The maximal muscular power (both instantaneous, w, and average, w-.) and the cross-sectional area of the left thigh (CSA) were measured on six subjects before (B) and after (A) prolonged exposure to high altitude (above 5000 m asl). w and w were determined during a standing high jump off both feet on a force platform, and CSA by computed tomography. It was observed that: (1) in B, body weight (BW) = 74.1 +/- 5.8 kg, w = 3330 +/- 460 W (44.8 +/- 3.4 W.kg-1). w-. = 1795 +/- 395 W (24.6 +/- 4.3 W.kg-1), and CSA = 184.5 +/- 23.1 cm2; 2) in A, BW = 70.4 +/- 6.6 kg, w = 3005 +/- 472 W (42.5 +/- 3.6 W.kg-1), w = 1531 +/- 267 W (21.9 +/- 3.1 W.kg-1), and CSA = 163.5 +/- 23.1 cm2. Thus, w and w-. were decreased both in absolute terms (-9.8% and -14.7%, respectively) and per unit BW (-5.1% and -11.0%). However, because of the concomitant decrease in CSA, when expressed per unit cross-sectional area of the muscle, w (9.04 +/- 0.71 and 9.20 +/- 0.72 W +/- cm2) and w (4.87 +/- 0.81 and 4.70 +/- 0.67 W/cm2) were unchanged. The intrinsic capacity of the muscle to generate explosive power is therefore preserved in A. It is concluded that the decrease in w and w after high-altitude exposure depends only on a net loss of muscle mass.

Conductive and convective heat flows of exercising humans in cold water

The apparent conductance (Kss, in W.m-2.degrees C-1) of a given region of superficial shell (on the thigh, fat + skin) was determined on four nonsweating and nonshivering subjects, resting and exercising (200 W) in water [water temperature (Tw) 22-23 degrees C] Kss = Hss/(Tsf-Tsk) where Hss is the skin-to-water heat flow directly measured by heat flow transducers and Tsf and Tsk are the temperatures of the subcutaneous fat at a known depth below the skin surface and of the skin surface, respectively. The convective heat flow (qc) through the superficial shell was then estimated as qc = (Tsf - Tsk).(Kss - Kss,min), assuming that at rest Kss was minimal (Kss,min) and resting qc = 0. The duration of immersion was set to allow rectal temperature (Tre) to reach approximately 37 degrees C at the end of rest and approximately 38 degrees C at the end of exercise. Except at the highest Tw used, Kss at the start of exercise was always Kss,min and averaged 51 W.m-2.degrees C-1 (range 33-57 W.m-2.degrees C-1) across subjects, and qc was zero. At the end of exercise at the highest Tw used for each subject, Kss averaged 97 W.m-2.degrees C-1 (range 77-108 W.m-2.degrees C-1) and qc averaged 53% (range 48-61%) of Hss (mean Hss = 233 W.m-2).(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma membrane fluidity in isolated rat hepatocytes: comparative study using DPH and TMA-DPH as fluorescent probes

The study of membrane fluidity is a rapidly expanding field of research and its interest in hepatology has been stressed recently. The present study is the first report concerned with the determination of membrane fluidity of isolated rat hepatocytes. The data have been compared with those obtained in plasma membrane fractions and subfractions (basolateral or canalicular) derived from homogenates. The fluorescent probes used to measure the fluidity were diphenylhexatriene (DPH) a 'classical' probe, and its derivative trimethylammoniodiphenylhexatriene (TMA-DPH) at 25 degrees C and at 37 degrees C. The values obtained with DPH were lower than those with TMA-DPH, probably due to the localization of the probes in different regions of the phospholipid bilayer. In addition, DPH revealed significant differences in the fluorescence polarization values obtained in isolated hepatocytes compared with membrane fractions, which was in contrast to TMA-DPH, where the respective values were of the same order of magnitude. This behaviour is probably due to the mobility of DPH in the membrane core and its rapid internalization into the cell, whereas TMA-DPH remains anchored for a long time on the cell surface. These findings suggest that TMA-DPH is a better probe than DPH for measuring the fluorescence polarization of whole isolated hepatocytes and that the use of different probes might be of help in exploring different zones of the membrane bilayer.

Azelastine in the prophylactic treatment of bronchial asthma: an Italian multicentre comparison with ketotifen

The prophylactic effectiveness of the phthalazinone derivative, azelastine was compared with ketotifen. A total of 111 patients, aged 18-65 years, from 10 centres was entered into this randomized, double-blind study. All patients had reversible asthma. After 1 week on placebo, patients were allocated to either 8 mg/day azelastine once or twice daily, or to 1 mg ketotifen, twice daily, for a further 12 weeks. Azelastine was more effective in improving respiratory function (forced expiratory flow in 1 s and peak expiratory flow rate) when given in the once daily regimen, whereas clinical measures (number of weekly asthma attacks) were most improved by twice daily dosing. There was no significant difference between the effectiveness of azelastine and that of ketotifen. Treatments were equally well tolerated and a low incidence of side-effects was reported. In conclusion, 8 mg/day azelastine, in either a single or twice daily dosage regimen may be regarded as providing effective prophylaxis against bronchial asthma.

[Etiopathogenetic role of metabolic, circulatory, sex factors and type and duration of diabetes in diabetic retinopathy. Investigation with vitreofluorophotometry]

We have studied metabolic, circulatory and vascular parameters in a group of 57 diabetics (37 affected by IDDM, 20 affected by NIDDM; 35 were males, 22 were females). Goals of present study were: 1) quantitative evaluation of the blood retinal barrier; 2) influence of the metabolic state, blood pressure, sex, type and duration of the diabetes on the ocular conditions; 3) relationship between ophthalmoscopic appearance of the retina and vitreous fluorophotometric recordings. We concluded that: a) ocular alterations depend by lipidic metabolism, blood pressure, sex, type and duration of the diabetes; b) vitreous fluorophotometry has proved a good device for early detection of retinal damages in the diabetic retinopathy.

Echinogenic action of L-alpha-lysophosphatidylcholine in Duchenne muscular dystrophy: a study on carrier detection

The percentage of echinocytes induced after red cell treatment with L-alpha-lysophosphatidylcholine in the blood of 16 patients affected by Duchenne muscular dystropy (DMD) has been evaluated. Moreover, 15 mothers, 10 sisters, and 15 fathers were also included in the study. We found an increased level of echinocytes in dystrophic patients and in known and possible carriers. Correlations were also evaluated between echinocytes and serum enzymes used in DMD diagnosis, showing an increase of echinocytes also in DMD carriers with normal levels of serum creatine kinase, lactate dehydrogenase, and aldolase. Our results suggest that the sensitivity of erythrocytes to L-alpha-lysophosphatidylcholine in DMD could be used as a diagnostic test for carrier detection.

Changes in membrane properties of erythrocytes and polymorphonuclear cells in psoriasis

Using fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene and its cationic derivative, 1-(4-trimethylaminophenyl)-6-phenyl-1,3,5-hexatriene, we evaluated membrane fluidity in living polymorphonuclear leukocytes and in erythrocytes of psoriatic patients. Our results have shown that erythrocyte membranes of psoriatic patients exhibit a decrease of fluidity. These changes were not associated with any relevant modifications of the cholesterol to phospholipid molar ratio. Moreover, we observed a decrease in polymorphonuclear leukocytes membrane fluidity associated with changes in chemotactic migration. Our results indicate changes of membrane fluidity involving membranes different from the epidermal cells and suggest the hypothesis of a defective membrane-cytoskeleton interaction in psoriasis.

Effect of antirheumatic drugs on lymphocyte membrane fluidity in rheumatoid arthritis: a fluorescence polarization study

We have demonstrated significant differences in 1,6-diphenyl-1,3,5-hexatriene fluorescence polarization values between lymphocyte membranes of untreated rheumatoid arthritis patients and lymphocyte membranes of patients treated with antirheumatic drugs, such as hydroxychloroquine and auranofin. No difference has been detected in rheumatoid arthritis patients treated with auranofin associated with 6-methylprednisolone. The results indicate that some drugs used in the treatment of rheumatoid arthritis induce changes of lymphocyte membrane fluidity. The positive correlations between fluorescence polarization values and objective indices of the disease activity, as erythrocyte sedimentation rate, C-reactive protein, fibrinogen level, and alpha 2-globulin, suggested that fluorescence polarization could be used in the study of the pharmacological action of antirheumatic drugs and in monitoring antirheumatic therapy.

Influence of auranofin on lymphocyte membrane fluidity in rheumatoid arthritis. A fluorescence polarization study

Using the fluorescence polarization of 1.6-diphenyl-1, 3, 5-hexatriene, the membrane fluidity of lymphocytes obtained from rheumatoid arthritis patients was measured during 12 months of auranofin treatment. Significant differences in fluorescence polarization values were observed following auranofin treatment. The correlations shown between fluorescence polarization values and the indices of rheumatoid arthritis activity, such as erythrocyte sedimentation rate, alpha 2-globulins, plasma fibrinogen levels and platelet count suggest that changes in lymphocyte membrane fluidity could be used to monitor the effects of auranofin therapy.

Altered properties of platelet membrane in childhood obesity

Using 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5,hexatriene (TMA-DPH) as fluorescent probe, we have studied platelet membrane fluidity and thrombin induced exocytosis in ten obese children and fifteen controls. Our results indicate a decrease of membrane fluidity, as shown by an increase of fluorescence anisotropy, in platelets from obese patients in comparison with the controls. Associated with the changes in membrane fluidity, platelets of obese subjects showed a decreased sensitivity to thrombin stimulation.

Age and sex related changes of plasma membrane fluidity in isolated rat hepatocytes

The influence of sex and age on membrane fluidity, has been investigated in 6, 12, 18 weeks old Sprague-Dawley rats. Fluorescence polarization (P) was determined at 37 degrees C with a Perkin Elmer MPF 44A fluorescence spectrophotometer. The fluorescent probe TMA-DPH was added to isolated hepatocytes prepared by collagenase method. The membrane fluidity was constantly lower in males than in females, but the difference was statistically significant only in the 12 weeks old group. Major differences appeared related to aging with a significant age-related decrease in fluidity in all animals.

[The MRI sites functioning in 1987 in France. Results of a survey]

A study of the 23 MRI sites functioning in France at the end of 1987 provides an overall view of the organizational and economic aspects of these sites as well as an initial assessment of their activity in terms of the types of equipment used and the institutions, private or public, within which they have been set up.

Changes of erythrocyte membrane fluidity associated with childhood obesity: a molecular study using fluorescence spectroscopy

Fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene has been used to investigate the physical state of erythrocyte membranes from 36 obese children in absence of endocrine and metabolic disorders involving alterations of blood lipid pattern. A decrease of membrane fluidity, as shown by an increase of fluorescence polarization, was evident in obese subjects in comparison with the controls. The study of membrane composition has revealed an increase of cholesterol content and of cholesterol to phospholipid molar ratio, both being positively correlated with the observed changes of membrane fluidity. Moreover a correlation of membrane fluidity is also observed with body-mass index and plasma cholesterol levels. The results are discussed in the light of the possible use of erythrocyte membrane as a model to detect early alterations in the exchanges between erythrocyte membrane and lipoproteins in obesity.

Renovascular hypertension: a non-invasive Duplex scanning screening

A Duplex-Scanner was used to screen 62 patients with severe hypertension, queried renovascular. Ten results were technically unsatisfactory and in the remaining 52 highlighted flow alterations in the renal arteries of 29 patients were found. Control angiographies confirmed renal artery stenosis in 27 cases. Comparative statistical analyses proved the test to be both highly sensitive and specific, considering other screening methods currently used in diagnosing renovascular hypertension--which include endovenous digital subtraction angiography. Results confirmed the Duplex-Scanner as a reliable renovascular hypertension screener as well as being a non-invasive method with no potentially toxic effects.

Changes of lymphocyte membrane fluidity in rheumatoid arthritis: a fluorescence polarisation study

Fluorescence polarisation of 1,6-diphenyl-1,3,5-hexatriene was used to study the lymphocyte membrane in rheumatoid arthritis. The increase of polarisation value in the patients (n = 27) compared with healthy controls (n = 32) suggests a decrease of membrane fluidity. Moreover, erythrocyte sedimentation rate (ESR) and plasma fibrinogen concentrations were positively correlated with lymphocyte fluorescence polarisation values (r = 0.66 and r = 0.76 respectively). The results suggest that the changes in lymphocyte membrane fluidity could be involved in the pathogenetic mechanism of rheumatoid arthritis.

Regional heat flows of resting and exercising men immersed in cool water

Trunk (HT), limb (HL), and whole-body (HDIR = HT + HL + Hforehead) skin-to-water heat flows were measured by heat flow transducers on nine men immersed head out in water at critical temperature (TCW = 30 +/- 2 degrees C) and below [overall water temperature (TW) range = 22-32 degrees C] after up to 3 h at rest and exercise. Body heat flow was also determined indirectly (HM) from metabolic rate corrected for changes in heat stores. At rest at TCW [O2 uptake (VO2) = 0.33 +/- 0.07 l/min, n = 7], HT = 52.3 +/- 14.2 (SD) W, HL = 56.4 +/- 14.6 W, HDIR = 120 +/- 27 W, and HM = 111 +/- 29 W (significantly different from HDIR). TW markedly affected HDIR but only slightly affected HM (n = 22 experiments at TW different from TCW plus 7 experiments at TCW). During light exercise (3 MET) at TCW (VO2 = 1.06 +/- 0.26 l/min, n = 9), HT = 122 +/- 43 W, HL = 130 +/- 27 W, HDIR = 285 +/- 69 W, and HM = 260 +/- 60 W. During severe exercise (7 MET) at TCW (VO2 = 2.27 +/- 0.50 l/min, n = 4), HT = 226 +/- 100 W, HL = 262 +/- 61 W, HDIR = 517 +/- 148 W, and HM = 496 +/- 98 W. Lowering TW at 7-MET exercise (n = 9, plus 4 at TCW) had no effect on HDIR and HM. In conclusion, resting HL and HT are equal. At TW less than TCW at rest, HDIR greater than HM, showing that unexpectedly the shell was still cooling. During exercise, HL increases more than HT but less than expected from the heat production of the working limbs. Therefore some heat produced by the limbs is probably transported by blood to the trunk. During heavy exercise, HDIR is constant at all considered TW; apparently it is regulated by some thermally dependent mechanism, such as a progressive cutaneous vasodilation occurring as TW increases.

Modification of lipid composition of erythrocyte membranes in chronic alcoholism

The lipid composition and microviscosity of erythrocyte membranes have been studied in chronic alcoholics with macrocytosis and minimal liver dysfunction. The findings have been compared with those obtained in subjects with macrocytosis not related to ethanol abuse. In all instances, macrocytosis was accompanied by an increased microviscosity of erythrocyte membranes, together with an increase of the cholesterol/phospholipid and of saturated/unsaturated fatty acids ratio. Both microviscosity and saturated/unsaturated ratio were significantly higher in alcoholics compared to subjects with macrocytosis not related to ethanol abuse. These findings confirm that altered lipid composition and fluidity of erythrocyte membrane may be observed in chronic alcoholics with minimal liver dysfunction, possibly due to the "stabilising" properties of ethanol - among a number of drugs- on biological membranes.