Biomedical subjects

M Tomassetti

Publications and source records attributed to M Tomassetti.

62 records · Page 4Linked to original sources

PubMedDate not supplied

Analysis of L-dopa in pharmaceutical preparations and of total phenols content in urine by means of an enzyme-amperometric sensor.

An enzyme-amperometric method is proposed for the analysis of total phenols and L-dopa; the method is based on the enzyme tyrosinase, which is immobilized in a Nylon membrane and coupled to an oxygen gas-diffusion amperometric electrode. The method was applied to the determination of total phenols in urine and to L-dopa in formulations and was evaluated as a promising alternative to currently adopted methods, e.g. to a classical spectrophotometric technique, chosen as a reference method.

Biosensing Techniques↗

PubMedDate not supplied

Cholanic acids determined in commercial drugs by means of a new ISFET device.

An ISFET device selective for cholanic acids, based on a PVC-sebacate membrane, containing benzyldimethylcetylammoniumcholate as exchanger, has been prepared, characterized and applied to the determination of cheno or ursodeoxycholic acid content of commercial pharmaceutical drugs and critical micellar concentration (CMC) values for cholate, deoxycholate and chenodeoxycholate. The results are compared with those obtained using previously described polymeric membrane sensors based on the same exchanger.

Calibration↗

PubMedDate not supplied

Epidural mepivacaine for cesarean section: effects of a pH-adjusted solution.

STUDY OBJECTIVE: To determine the clinical effects of the alkalinization of 2% mepivacaine with epinephrine used for epidural block during cesarean section. DESIGN: Randomized, double-blind, placebo-controlled (standard commercial preparation of 2% mepivacaine with epinephrine) study. SETTING: Inpatient obstetric department at a general hospital. PATIENTS: Seventy patients scheduled for elective cesarean section under epidural anesthesia. INTERVENTIONS: Two groups of 35 patients each receiving either the standard commercial preparation of mepivacaine or the pH-adjusted solution (prepared with the addition of 0.1 meq/ml of sodium bicarbonate to the standard commercial solution). MEASUREMENTS AND MAIN RESULTS: Measurements of sensory (pinprick) and motor (Bromage's criteria) block were taken at 1- to 2-minute intervals beginning after the completion of the epidural injection. Increasing the pH of the mepivacaine resulted in a significant shortening of the time of analgesia onset (9.3 minutes compared with 16.01 minutes, p less than 0.01) and of peak effect (11.1 minutes compared with 21.2 minutes, p less than 0.01). The alkalinization did not affect duration of the block, intensity of motor block, or mean dose of local anesthetic used. CONCLUSION: The alkalinization allowed the surgery to proceed more rapidly, significantly decreasing the time interval between epidural block and delivery of the infant.

Adult↗

PubMedDate not supplied

Lecithin determination in foods and drugs by an amperometric enzymatic sensor.

A new enzymatic-amperometric method for the determination of lecithin as an additive in foods and as a component of commercial drugs is proposed. The method is based on a detector realized with two enzymes, choline oxidase and phospholipase D, the former immobilized, the latter free in solution, and by an oxygen Clark electrode. The experimental conditions were investigated in order to obtain wide applications with different samples. Extraction or dissolution of the samples in ethanol proved satisfactory. The precision of the method was found to be about 1.5%, inaccuracy less than or equal to 4%. Correlation between the proposed enzymatic-amperometric method and an enzymatic-spectrophotometric reference method was satisfactory.

Alcohol Oxidoreductases↗

PubMedDate not supplied

Identification of different types of imperial age marble finds using instrumental chemical analysis and pattern recognition analysis.

A physical-chemical characterisation of several marbles frequently used in ancient times for artistic or decorative purposes was performed in support the work of historians and restorers. The data were obtained using several different types of instrumental chemical methods (Thermogravimetry, Differential Thermal Analysis, X-ray Diffractometry and ICP Plasma Emission Spectroscopy) and have been summarised in short tables. The data have already proved useful in the identification of a small number of finds (statues or architectonic elements) from Ancient Rome (Imperial Age, 2nd-3nd cent. A.D.) for the purpose of which also a well-known pattern recognition analysis software package was used for data processing. In practice, the research showed that an organised set of chemical data obtained using several modern instrumental methods can provide a valid basis for the reasonably rapid and reliable identification of the type of marble used to make artistic artifacts that have not yet been subjected to typological study.

Calcium Carbonate↗

PubMedDate not supplied

[Acute effects of a new type of lipidic emulsion in critical patients].

A new type of 10% lipidic emulsion based on safflower oil and soya (Liposyn II, Abbott, Latina) characterised by a high linoleic/linolenic acid ratio was administered in random, double blind fashion with 10% Intralipid to 20 subjects submitted to major surgery of the digestive system. Dosage was 1.2 g/kg at an infusion rate of 2.6 ml/kg/h. In order to evidence possible in vivo inter-reactions between proteins of the acute post-aggressive phase and these emulsions, serial samples were used to measure haemogasanalytic parameters, plasma levels of triglycerides and serum levels of protein C-reactive and fourth complement factor. Both emulsions proved well tolerated and there was no evidence of general or administrative site reactions. The plasma levels of triglycerides underwent an increase during the test, with no significant differences between the two groups of patients. Notwithstanding the high serum levels of protein C-reactive of the subjects in question, there was no evidence of activation of the complement system nor alteration in haemogasanalytic parameters with the two lipidic emulsions adopted.

Aged↗

PubMedDate not supplied

Maternal analgesia and neonatal effects of epidural sufentanil for cesarean section.

This study was designed to evaluate the maternal intraoperative and postoperative analgesia and neonatal effects of adding sufentanil to epidural anesthesia for cesarean section before the skin incision. Forty-five multipara were randomized in three equal groups to receive sufentanil 80 micrograms, 50 micrograms, or saline with the epidural lidocaine. Intraoperative and postoperative analgesia and side effects were recorded. Infants were evaluated by Apgar score at one and five minutes and by Neurologic and Adaptive Capacity Score and Early Neonatal Neurobehavioral Scale at one, four and 24 hours of life. Superior analgesia, with no intraoperative requirements for supplemental narcotics, was obtained when either 80 micrograms or 50 micrograms sufentanil were added to lidocaine. Postoperative analgesia was prolonged after sufentanil, but side effects increased with the greater dose. The infants whose mothers received 80 micrograms sufentanil showed a mild neurobehavioral depression. It is therefore concluded that the addition of 50 micrograms of sufentanil improves both intraoperative and postoperative analgesia without significant neonatal effects.

Adult↗

PubMedDate not supplied

Effect of stromal cells from human lymph nodes on the growth of osteosarcoma cell lines.

We investigated whether stromal cells obtained from human tonsils could interact and modulate the proliferation of the osteosarcoma cell in order to determine why lymph node metastases usually have a low incidence and remain occult using routine examinations. The effects of the supernatant of resting or activated stromal cells were analysed on osteoblastic cell proliferation of three different cell lines (HOS, U2, OS, MG-63). Only the proliferation of MG-63 was significantly inhibited. The direct adhesion of stromal cells to the osteosarcoma cell lines caused a greater inhibition of the proliferation of all three lines tested.

Cell Communication↗