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Biomedical subjects

M Mazzoni

Publications and source records attributed to M Mazzoni.

At least 73 records · Page 4Linked to original sources
PubMed1983

Thermodynamic behaviour of membrane enzymes in Duchenne muscular dystrophy.

Erythrocyte ghost preparations have been prepared from blood of Duchenne patients (DMD), female carriers of the disease and controls. Arrhenius plots of Na+, K+-ATPase activity of these membrane preparations show a biphasic response for controls. For 75% of DMD and carriers the response is monophasic. This is not an inherent property of the membrane since it can vary over time in the one individual and it can be induced in normal membranes by preincubation with DMD plasma. Arrhenius plots of AChE activity showed no such difference between the three sources of blood.

Acetylcholinesterase↗
PubMed1982

[Intestinal mechanisms of compensation and morphologic and functional adaptation after resection of bypass].

The intestine's ability to adapt following extensive resection is well known, and includes augmentation in calibre and the thickness of the wall, increased villus height, changes in motility, and qualitative and quantitative alterations in the flora. Positive identification of the mechanisms through which this morphological and functional adaptation takes place still forms the subject of research. An account is given of the latest views concerning the way in which compensation of the intestine takes place after resection and by-pass surgery.

Adaptation, Physiological↗
PubMed1980

[Dietetic considerations of the peptic ulcer treatment (author's transl)].

Stated that the alimentary inconguities, the improper mastication and the quickly eaten of foods are to avoid for the direct irritant effect on the stomach, the authors have examinate the various dietetic treatments, imploied for peptic ulcer and they conclude that only during the acute clinical phase more restrictive regimens are necessary. When the patient in on way of recovery, the alimentation must be free in agreement to the tolerance and personal taste using more variety of food. Moreover it's necessary to remember that the patient is not an "ulcer", but "his ulcer" be treated with the psycho-pathological implication correlated.

Acute Disease↗
PubMed1980

[Nosology of contraceptives: hematological and ultrastructural observations after experimental administration of low dosage contraceptives (author's transl)].

A further experimental study on changes produced in rabbits by low dosage contraceptives is presented. The administration has been continued for six months. Serum biochemical and hepatic ultrastructural findings are in agreements with literature data. On the contrary the early changes of cardiac microcirculation and chiefly renal glomerular tuft seem to be rather unusual. The weight to be attached to the knowledges descending from the presented data in assessing allowance of contraceptive treatments in human subjects and aiming preventive medicine purposes is emphasized.

Animals↗
PubMed1980

[Effects of clofibrate on rabbit kidneys].

The Authors have investigated the effect on the kidney of experimental administration of 250 mg of clofibrate in rabbits. After 36 days of treatment the animals are sacrificed and histological and ultrastructural examination are made. The seriographies an alteration of the glomerular membrane and a mild fragmentation of endothelial lamina. Swelling of the proximal tubular cell is also revealed. It is concluded that this early injury of the nephron is reversible and more severe manifestation in man can occur. This drug must be strongly avoided.

Animals↗
PubMedDate not supplied

Recent innovations in total liquid ventilation system and component design.

In addition to partial liquid ventilation (PLV), total liquid ventilation (TLV) is being explored as a potential therapy to mitigate ventilator-associated lung injury and acute lung failure. TLV is ventilation of the completely liquid-filled lung using tidal flow of oxygenated perfluorochemical (PFC) liquid delivered by a "liquid ventilator." Most TLV research to date has focused on "small" lung (animals < 20 kg; vast majority < 5 kg), with primary relevance to its use in children. Recent investigations regarding TLV in larger lungs have helped define new design challenges for liquid ventilator systems to succeed as clinical products. Adult TLV requires the delivery of significantly higher liquid tidal volumes, with proportionately greater O2 and CO2 exchange. Although a simple scale-up of liquid ventilator components such as pumps, tubing, fittings, and gas and heat exchangers might be considered the most straightforward way to compensate for the increased demand, there are a number of practical problems with this approach. These include requirements to: 1) minimize priming volume, 2) minimize PFC evaporative loss, 3) suppress flow-induced cavitation in fittings and components, 4) monitor and control ventilation based on pressure signals exhibiting noise, 5) maintain ability and accuracy of delivered breaths in a fluid mechanical environment having higher inertial forces and pressure losses than for small lung systems, 6) use disposable or sterilizable fluid-contacting components, and 7) maintain PFC materials compatibility. TLV system and component innovations implemented on a new large-animal liquid ventilator prototype are presented. The advantages of new pumps, gas exchangers, and temperature-control components are discussed.

Adult↗
PubMedDate not supplied

Dose monitoring in Partial Liquid Ventilation by infrared measurement of expired perfluorochemicals.

Patients undergoing Partial Liquid Ventilation (PLV) with the perfluorochemical liquid perflubron (PFB) continuously evaporate the drug from the lung during ventilatory expiration. In this study, two infrared (IR) devices, a modified industrial analyzer ("experimental prototype") and a custom-designed device suitable for use in a clinical environment ("clinical prototype"), were calibrated and validated on the bench to measure a range of PFB concentrations (CPFB) in a gas stream. PFB loss from the lung (area under the CPFB-vs-time-curve) could be correlated during PLV simulation with changes in tidal volume, breathing rate, and variable CPFB-vs-time profiles. The two IR devices produced nearly identical measurements for the same CPFB standards (maximum deviation = 1.5%). The experimental IR prototype was tested in 17 anesthetized, paralyzed, and ventilated swine (42-53 kg) to quantify the total amount and rate of evaporate loss of PFB over 12 hours of PLV, both with and without periodic supplemental PFB doses. The residual PFB volumes in the animal lungs at the end of the study, as determined by a gravimetric postmortem lung method, were found to agree on average for all animals to within 10% of the residual PFB volume as predicted by the IR approach. Furthermore, the IR signal of CPFB does not appear to correlate with the absolute amount of PFB in the lungs, but may reflect the relative proportion of PFB-wetted airway and alveolar surface. The authors conclude that IR quantitation of PFB evaporative loss is acceptably accurate for extended periods of PLV and may be a useful tool in the clinic for PFB dose monitoring and maintenance, thereby helping to optimize PLV treatment.

Algorithms↗
PubMedDate not supplied

A closed rebreathing system for dose maintenance during Partial Liquid Ventilation.

Partial Liquid Ventilation (PLV), a treatment for acute respiratory failure in which the lungs are filled, either partially or to functional residual capacity (FRC), with perfluorochemical (PFC) liquid while the patient is on mechanical gas ventilation, has progressed to clinical trials using the PFC perflubron (PFB). Because gas expired during PLV is laden with PFB vapor, PFB is lost via evaporation, which increases dose consumption and necessitates periodic redosing. A device has been developed to minimize evaporative loss by confining PFC vapor to a gas volume breathed by the patient, which is isolated from the ventilator. This closed rebreathing system works with the ventilator such that after the lung is filled with PFB, the patient is connected to the rebreathing system, with breathing still "driven" by the ventilator. The rebreathing system consists of two gas circuits, or compartments, separated by a flexible bag (in a box) partition. One compartment is in gas communication with the lung, while the second communicates with the ventilator. The O2 level on the patient side is matched to that on the ventilator side by sensing gas concentrations and by feedback control of O2 introduction. Similarly, air is introduced into the patient side under pressure-based feedback control to maintain a constant gas volume. On inspiration, the ventilator delivers the tidal volume (breath) into the box surrounding the bag, which, in turn, is transmitted through the bag to the lung. On expiration, the process is reversed. Unidirectional circulation of gas in the rebreathing circuit is achieved via check valves, and expired CO2 is removed by a barium hydroxide lime cartridge. Airway humidification is maintained by captive water vapor in the system and water vapor from the CO2 absorber. It is recommended that flow, pressure, O2, and CO2 levels be monitored at the patient "Y," i.e., the proximal end of the endotracheal tube. Performance data from both in-vitro experiments and in-vivo PLV experiments in pigs are presented. The authors conclude that with the closed rebreathing system, the dose can be safely maintained with fewer redosing procedures, and an approximately 90% savings in dose is achieved.

Animals↗
PubMedDate not supplied

Category-specific semantic disorders in Alzheimer's disease.

A striking dissociation between the inability to identify living things plus food, along with a preserved ability to identify inanimate objects has been observed in patients who are recovering from herpes simplex encephalitis. In order to find out if a similar dissociation is also present in Alzheimer's disease (where the suspected initial site of parenchymal atrophy involves the same areas affected by herpes simplex virus), we carried out five experimental linguistic tasks to compare Alzheimer's patients' performance therein with that of vascular dementia patients and controls. Our results indicate a constant parallel between the category-specific semantic impairment of Alzheimer's patients and that described in patients recovering from herpes simplex encephalitis. The dissociation of living things+food vs inanimate objects in Alzheimer's disease appears to be of diagnostic value: it is not present in vascular dementia.

Alzheimer Disease↗
PubMedDate not supplied

[Paralysis of the parasympathetic ocular nerve after influenza syndrome].

A 41 year-old-man developed diplopia, bilateral ptosis, paralysis of conjugate eye movement upwards and horizontal, with dilated and fixed pupils, after an influenza syndrome. Radiological, cerebrospinal fluid and electrophysiological data were normal, except BAEPs. The different aetiologies and pathogenesis are discussed.

Adult↗
PubMedDate not supplied

[Parkinsonian syndrome during viral meningoencephalitis].

During a viral meningoencephalitis, a 60-year-old woman developed a full parkinsonian syndrome, unchanged four months after the onset. The viral researches demonstrated an increase of the anti-CMV antibodies, especially in the cerebrospinal fluid. CSF's and neuroimaging data are discussed.

Female↗