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Biomedical subjects

F Forni

Publications and source records attributed to F Forni.

At least 37 records · Page 2Linked to original sources
PubMed1990

Oxidative stress of red blood cells stored for transfusion use.

Some oxidative indexes and the level of reduced glutathione have been determined on red blood cells stored for transfusion use. Conjugated dienes show a concentration which increases until around the third week of storage and then comes back to lower values. On the contrary malonyldialdeyde shows a decreasing level until the third week and then rises rapidly to very high values. Reduced glutathione rises until about the end of the second week and then falls to very low values. Free haemoglobin continuously rises through the whole period of storage; from these data it is evident that a storage time not exceeding 21 days gives the best transfusion results.

Alkenes↗
PubMed1989

Effect of montmorillonite on drug release from polymeric matrices.

Drug release from matrices of polyvinyl alcohol was affected by molecular weight and solubility of the drugs (either sodium salicylate or papaverine hydrochloride), and by the matrix loading. - Montmorillonite addition to the matrix formulation modified only the release constant of papaverine hydrochloride owing to drug interaction with the clay by an ionic exchange process. The kinetics exponent was affected a little bit by interaction of the drug with montmorillonite, whereas the influence of the matrix loading was more remarkable.

Bentonite↗
PubMed1989

Distribution of drugs in polymers loaded by swelling.

Ethylene:vinyl acetate pellets were loaded at 20 degrees C by swelling the polymer with 1 and 3% (w/v) chloroformic solutions of tolbutamide. The energy dispersive X-ray analysis showed different concentrations of the tolbutamide sulfur in the pellets sections according to the loading time. At the beginning of the loading process, the sulfur in the pellets showed two concentration peaks which later joined in the center of the section before reaching a homogeneous distribution. The concentration peaks might depend on a drug sieving process as the solution flow reaches a less swollen inner area. Therefore, the concentration distribution of the drug would be affected by the size of the polymer network, which is related to the volume of the solvent in the polymer. Another possible explanation of these concentration profiles is that they could be a result of the solvent evaporation process. The concentration distribution of the drug becomes homogeneous only after the complete swelling of all of the polymer.

Chemistry, Pharmaceutical↗
PubMed1987

Surface area and crystallinity of Form A of chloramphenicol palmitic and stearic esters: which one is the limiting factor in the enzymatic hydrolysis?

Chloramphenicol stearic and palmitic esters in the polymorphic Form A, when ground for 85 h showed an in-vitro enzymatic hydrolysis rate constant (Khydr), the value of which was the same as that of a commercial Form B. The increase in the rate of the enzymatic hydrolysis was not related to the specific surface area as shown by the fact that the micronized Form A, having a higher specific surface area value than ground Form A, showed the same Khydr as the unground Form A. The Khydr value of the ground Form A could be the result of an increase in the crystalline disorder brought about by the grinding process.

Chloramphenicol↗
PubMed1983

[Non-invasive recording of the His bundle electrogram: choice of leads and reliability of the "averaging" technic].

An improvement in detecting His bundle activity using a Marquette high resolution Mac unit, without pharmacologic depression of AV node conduction, was obtained with two surface lead systems, which were selected on the basis of the His bundle anatomical position and its electrostimulation axis. In 8 patients the direction of the His bundle bipolar stimulation vector was evaluated in the frontal plane, on the orthogonal leads and with map of the chest potential. In 39 patients the surface recording, using high-gain amplification, filtering between 50-300 Hz and an averaging of 256-512 cycles, was obtained by positioning the electrodes in the following sites: manubrium sterni-xiphisternum-V4. When this lead system failed, it was replaced by another one, which included V4-right sternal and right vertebral border at the level of the 3rd intercostal space. In 24 patients (PR less than 0.16" in 4 cases) intracavitary and surface H-V recording were compared. The surface interval was measured between the apex of the surface "blip" and onset of the QRS. Sensitivity was 86% with a good correlation (r = 0.94) between invasive and non-invasive measurements. The surface leads, in which the His bundle activity was best detected, were the manubrium-xiphisternum (on the midsternal line) and V4-right vertebral border at the 3rd intercostal space level. Our external measurement technique avoids subjective misinterpretations; the surface H-V interval was on an average 6 msec. shorter than the invasive one. The upper normal value of non-invasive H-V interval is therefore 50 msec in our measurement method.

Aged↗