Arteriovenous fistula obstruction and expression of platelet receptors for von Willebrand factor and for fibrinogen (glycoproteins GPib and GPiib/iiia) in hemodialysis patients.

Platelet surface receptors for von Willebrand factor and for fibrinogen (glycoproteins GPIb and GPIIb/IIIa) were studied with monoclonal antibodies CD42 and CD41 and cytofluorometry in 31 healthy subjects, 10 hemodialysis patients with no A-V fistula obstruction (patent original fistula), 10 hemodialysis patients with frequent A-V fistula obstruction (more than twice), 12 patients with mild chronic renal failure (creatinine 1.75 +/- 0.40 mg/100 ml), 11 patients with advanced chronic renal failure (creatinine 5.62 +/- 1.22 mg/100 ml), and 10 patients with end-stage renal disease (ESRD) treated with peritoneal dialysis. There was a significant increase of platelet surface glycoproteins GPIb and GPIIb/IIIa in the population of hemodialysis patients with frequent A-V fistula obstruction. The expression of these platelet receptors might be related to the prothrombotic tendency of a group of patients with ESRD, who suffer more occlusive and thrombotic events of the A-V fistula. This group of patients may also have a higher frequency of systemic thrombotic and atherosclerotic complications.

Slow-to-fast transformation of denervated soleus muscle of the rat, in the presence of an antifibrillatory drug.

The myofibrillar changes of rat denervated soleus muscle were studied in the presence and in the absence of an antifibrillatory drug. After bilateral sciaticotomy, a concentrated solution of procainamide hydrochloride was steadily released, by way of a miniosmotic pump, in the space between the soleus and the gastrocnemius muscles of one leg. Fibrillation activity of soleus muscles was checked electromyografically at 3- to 5-day intervals. On the 21st day following denervation the muscles were excised, stained for adenosine triphosphatase activity and analysed for myosin heavy chain (MHC) isoforms. In the denervated-procainamide-treated muscles fibrillation was consistently (-75% on average) depressed in comparison to the contralateral denervated muscles. Type 1 (slow) fibres and MHC isoform were also significantly reduced, to the advantage of type 2A (fast) fibres and MHC isoform. The results support the view that denervation inactivity, like other kinds of muscle inactivity, favours the expression of fast type myofibrillar isoforms, and that this effect is counteracted, at least partially, by the spontaneous activity of the denervated muscle.

["On line" processing using a microcomputer of bioelectric signals of gnathological significance]. / Elaborazione "on line" mediante microcomputer di segnali bioelettrici di interesse gnatologico.

EMG during diagnosis and treatment monitoring in orthodontics and gnatology has become widely used. The Authors describe the linking of a PC to an amplifier of EMG signals. The program is then reported and commented on.

[A proposed method for analysis of the correlation between electromyographic and cephalometric parameters]. / Proposta di una metodica per l'analisi della correlazione tra parametri elettromiografici e cefalometrici.

This work reports on a method of analysis and statistical correlation of electromyographic and cephalometric parameters. Has been employed a computer as oscilloscop with digital memory.

Emission of microvesicles and erythrocytic spherocytation.

We have examined mathematically the "cause-effect" relationship between the phenomenon of emission of microvesicles and that of erythrocytic sphericitation, especially when the age of the cell is the main factor involved.

Absorption and disposition kinetics of flunoxaprofen and benoxaprofen in healthy volunteers.

Flunoxaprofen is a new nonsteroidal antiinflammatory agent that, like benoxaprofen, inhibits leukotriene rather than prostaglandin synthesis. The absorption and disposition kinetics of flunoxaprofen and benoxaprofen have been compared in six healthy volunteers after oral administration of 100 mg of each drug. The two drugs showed similar absorption characteristics, whereas the distribution and elimination processes were much faster for flunoxaprofen. The renal route of elimination appeared to contribute significantly less to the disposition of flunoxaprofen. These kinetic characteristics render less likely the risk of excessive drug accumulation with flunoxaprofen, especially in the presence of reduced renal function.

[An outline for applying to human plasma classical theories on the viscosity of colloidal suspensions and macromolecular solutions (Kuhn, Simha, Taylor et al.). (A brief preliminary outline. I)]. / Schema di trasposizione al plasma umano di teorie classiche sulla viscosità di sospensioni colloidali e di soluzioni macromolecolari (Kuhn, Simha, Taylor, et al.). (Breve traccia preliminare. I parte).

This methodological investigation is a formal and short outline of a rheological model for human plasma. Such a model proposal originates from equations and formulae for viscosity of colloidal suspensions and macromolecular solutions established by several authors (R. Simha, G. I. Taylor, W. and H. Kuhn). The model here proposed requires very hard oversimplifications and it may be considered as a semiempirical approach.

[Metabolic influences on the onset of fibrillation and on membrane potentials of denervated muscles]. / Influenze metaboliche sull'insorgenza della fibrillazione e sul potenziale di membrana nei muscoli denervati.

Fibrillation activity and membrane depolarization which follow denervation, were studied in skeletal muscles of control and pretreated adult rats. The investigation was carried out on both fast (Tibialis Anterior) and slow (Soleus) muscles. The pretreatment consisted in prolonged (4 days) starvation, or Streptozotocin-induced diabetes, preceding denervation. Denervation was performed by cutting the sciatic nerve. In fast as well as in slow muscle, both pretreatment significantly delayed the onset of fibrillation. Starvation enhanced depolarization only in fast muscle, while diabetes was effective also in slow muscle. The results support the view that membrane depolarization (but not fibrillation activity) in denervated muscle is related to an altered carbohydrate metabolism.

Effects of two synaptic activators, calcium and ethanol, on MEPP distribution in time.

Miniature end-plate potentials (MEPPs) were recorded intracellularly from sartorius muscle of Rana esculenta. Tracings were divided into time bins whose duration approximated one-fifth of the mean interval between consecutive potentials. The observed number of bins containing 0, 1, 2, ... MEPPs was compared, by the X2 test, with the number calculated from the Poisson equation. MEPP timing was analyzed in the absence as well in the presence of Ca2+ (1 mM, 2.5 MM, and 15 mM). In half of the experiments, 0.5% ethanol was added to the bathing solution. In the absence of Ca2+, MEPP timing fitted the Poisson predictions. On adding Ca2+, the fit became poor and MEPPs showed the tendency to cluster. At 15 mM Ca2+, no experiment proved to be Poissonian. Though increasing the frequency of MEPPs similarly to Ca2+, ethanol maintained a Poissonian release of transmitter at any concentration of Ca2+. It is suggested that ethanol masks the effects of Ca2+ on MEPP timing by also inducing the discharge of transmitter outside the Ca2+-dependent sites of exocytosis in the presynaptic membrane.