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Biomedical subjects

A Masoni

Publications and source records attributed to A Masoni.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

Toxicity of fatty acid 18:5n3 from Gymnodinium cf. mikimotoi: II. Intracellular pH and K+ uptake in isolated trout hepatocytes.

Effects of octadecapentaenoic acid 18:5n3 and other related polyunsaturated fatty acids present in gymnodinium cf. mikimotoi were tested in isolated trout hepatocytes. These exotoxins decreased intracellular pH followed by a slow recovery to initial value and alkalinization of acidic compartments, suggesting an inhibition of vacuolar H(+)-ATPases. Moreover, addition of 18:5n3 to the extracellular medium induced a decrease of K+ uptake into hepatocytes as a result of Na,K-ATPase inhibition. However, high concentrations (10(-5)-10(-3) M) are necessary to induce these effects.

Acridine Orange↗
PubMedDate not supplied

Toxicity of fatty acid 18:5n3 from Gymnodinium cf. mikimotoi: I. Morphological and biochemical aspects on Dicentrarchus labrax gills and intestine.

We present evidence for the toxic effects of fatty acid 18:5n3 (octadecapentaenoic acid) in the gills and intestine of the sea bass Dicentrarchus labrax. Light microscopic observation of gills showed strong mucus production and alteration of ionocytes. The Mg- and Na,K-ATPase activities were inhibited, with IC50 values of 10(-3) and 1.6 x 10(-4) M, respectively. Results are discussed in relation to osmoregulation.

Animals↗
PubMedDate not supplied

Effects of lead loads on branchial osmoregulatory mechanisms in the rainbow trout Oncorhynchus mykiss.

Exposure of rainbow trout to lead chloride (PbCl2, 1 ppm) in fresh water killed all animals within 16 days. Exposure to this lethal dose for 6 days only showed a significant increase in the haematocrit. Calcium, sodium and chloride concentrations in plasma were not notably modified. Both the influx and the net flux of sodium fluctuated much less than the diffusional water fluxes through secondary lamellae in gills. Branchial Na,K-ATPase, Ca-ATPase and HCO3-ATPase activities were not sensitive to lead toxicity. Lead caused a cellular 'wave-shaped' degeneration and renewal with modification in the number and morphology of chloride cells. Results are discussed in relation to the hydromineral balance of the trout.

Adenosine Triphosphatases↗
PubMedDate not supplied

Effects of copper on gill structure and transport function in the rainbow trout, Oncorhynchus mykiss.

Effects of copper were studied in freshwater adapted rainbow trout using the perfused head preparation. In its monovalent chemical form, copper at millimolar concentrations had no significant effects on Na+ and water transport. By contrast, the divalent form produced an increase in gill perfusion pressure, a significant reduction in Na+ influx and water fluxes and reversed Na+ net flux. Observations by light microscopy showed important cell damage (oedema, mucus production, cellular desquamation). By electron microscopy there was smoothing of apical membranes, swelling of the tubular system and destruction of mitochondria. The Na, K-ATPase activity was totally suppressed and residual ATPase activity largely inhibited by 1 mM Cu2+. There was inhibition of the Na,K-ATPase activity with an IC50 of approximately 10 microM of total copper (free and bound cupric fractions). As active sodium transport is located on the secondary lamellae, our results show that its entry mechanism is inhibited at that level by cupric ions only. Results are discussed in relation to hydromineral balance of the trout.

Analysis of Variance↗
PubMedDate not supplied

Free insulin concentrations in immediately extracted plasma samples and their relationships to clinical and metabolic parameters in insulin-treated diabetic patients.

The relationships between free insulin and various clinical and metabolic parameters in insulin-treated diabetic patients are still not clear, possibly because of the technical difficulties in measuring free insulin. Recently, it has been demonstrated that in the presence of insulin antibodies only immediate centrifugation of blood and extraction of insulin antibodies provide an accurate evaluation of in vivo free insulin concentrations. In this study we evaluated the relationships between free and bound insulin levels, insulin antibodies, metabolic control and insulin requirement in 38 insulin-treated diabetic patients, in whom plasma free insulin was assayed in immediately processed samples. The main findings of our study are as follows. Free insulin concentrations ranged from 2.5 to 54 microU/ml; no difference was found between males and females; the unbound hormone level was inversely correlated to fasting plasma glucose (p less than 0.01) and HbA1c (p less than 0.02); a positive correlation was shown between free insulin and daily insulin dose; finally, free insulin concentrations were not correlated with insulin antibody binding.

Adult↗
PubMedDate not supplied

Reproducibility of electrophysiological parameters of sinus node following autonomic blockade.

We investigated the reproducibility of sinus node cycle length (SCL), corrected sinus node recovery time (CSRT) and sino-atrial conduction time (SACT) during the control state and following autonomic blockade in 25 patients (mean age: 56.9 +/- 13.8 years). Autonomic blockade was induced by i.v. administration of propranolol (0.2 mg/kg) and atropine (0.04 mg/kg). The electrophysiological study was repeated after 24 hr and the results were compared. The patients were divided into two groups: Group 1 (15) with normal and Group 2 (10) with abnormal intrinsic sinus node function. Following autonomic blockade in Group 1 the daily variations in SCL, CSRT and SACT were very slight whereas in Group 2 there was far greater variability in these parameters. However, in the latter group there were no patients who changed their status from prolonged to normal intrinsic CSRT on the second study, whereas SACT changed its status in 2 patients. In Group 1 the daily variations in sinus node parameters were much slighter following autonomic blockade than during the control state. In Group 2 the variations were very similar during control and following autonomic blockade. These data suggest that: (1) following autonomic blockade the reproducibility of sinus node parameters is very good in Group 1, whereas in Group 2 several patients show marked daily variations in sinus node parameters; (2) following autonomic blockade the sinus node electrophysiological parameters are meaningful in diagnosing an involvement of intrinsic sinus node function; and (3) in patients with abnormal sinus node parameters during control state, but with normal intrinsic sinus node function, the daily variations are mainly due to change in autonomic tone, whereas when the intrinsic sinus node function is abnormal, the day to day variations during control state appear due predominantly to intrinsic sinus node abnormalities.

Adolescent↗
PubMedDate not supplied

Behavioral versus pharmacological treatments for essential hypertension: a pilot study.

This is the only study so far in which a behavioral treatment is compared with standard pharmacological treatments for essential hypertension. Three groups of five subjects each were compared: 1. pharmacological treatment; 2. relaxation treatment (autogenic training); 3. the combination. The group given antihypertensive medication was significantly more improved (as determined by blood pressure decrease) by the fourth quarter of the treatment as compared with the relaxation treatment or with the combination. This advantage for routine amounts of antihypertensive medications vs. behavioral treatments is consistent with the only other data from a similar comparison that is available [1].

Adult↗
PubMedDate not supplied

Salivary immunoreactive insulin concentrations are related to plasma free-insulin levels in insulin-treated diabetic patients.

Salivary immunoreactive insulin was measured in 45 insulin-treated diabetic patients directly from saliva samples by a radioimmunoassay procedure. Mean and median fasting salivary immunoreactive insulin was respectively 88.5 and 54.0 pmol/L (range 12.2-633.6 pmol/L); fasting salivary insulin values were positively correlated with steady-state plasma free-insulin levels measured in immediately extracted plasma samples (r = 0.62, p less than 0.001) and with daily insulin dose (r = 0.32, p less than 0.05). After subcutaneous injection of 15 U regular insulin in 6 type 1 diabetic patients, salivary insulin concentrations increase reflected that of plasma free-insulin during a 6 h period although with a 60 min time lag. Mean salivary insulin values and plasma free-insulin concentrations were significantly correlated to each other both at each time point (p less than 0.001) and when the mean salivary insulin levels were plotted against the mean plasma free-insulin values 60 min earlier (p less than 0.001). These results suggest that the measurement of salivary immunoreactive insulin (that is easier, faster and cheaper than plasma free-insulin assay) may be usefully employed as an approximation of plasma free-insulin concentrations for clinical and research purposes in patients with circulating anti-insulin antibodies.

Adult↗