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Biomedical subjects

M Ferrari

Publications and source records attributed to M Ferrari.

At least 109 records · Page 6Linked to original sources
PubMed1992

Effects of pinacidil on guinea-pig isolated perfused heart with particular reference to the proarrhythmic effect.

1. The effects of pinacidil (10, 30, 50 microM) on contractility (+dP/dtmax), coronary perfusion pressure (cP), and ECG intervals (PR, QRS, QT) have been studied on constant-flow perfused guinea-pig hearts, driven at four frequencies (2.5, 3, 3.5, 4 Hz). 2. Pinacidil decreased +dP/dtmax, cP and the QT interval in a dose-dependent manner, whereas the PR interval was increased. QRS duration was not modified. All these effects were independent of driving frequency. Pinacidil decreased the interval from Q-wave to T-wave peak (QTpeak) to a greater extent than the QT interval, thus decreasing the QTpeak/QT ratio. This effect, unlike that on QT interval, was more evident at the highest frequency of stimulation. 3. In 4 out of 20 hearts treated with pinacidil sustained ventricular fibrillation (VF) occurred following a short run of premature ventricular beats (R on T phenomenon). 4. In separate experiments, an attempt to induce VF electrically was made at drug concentrations ranging from 10 microM to 100 microM (8 experiments for each concentration). In control conditions and at the lowest concentrations of pinacidil tested (10 microM) VF could never be induced; in the presence of 30 microM pinacidil VF was induced in 5 out of 8 experiments. Drug concentrations higher than 50 microM permitted the induction of VF in every case. 5. Although the concentrations of pinacidil producing ventricular fibrillation are 30-40 times higher than those found in patients under long term treatment with this agent, it is suggested that caution should be used in prescribing this drug, at least in patients suffering from myocardial ischaemia.

Animals↗
PubMed1992

Marginal leakage of a new adhesive restorative system: a preliminary in vivo investigation.

The efficacy of newly developed adhesive restorative materials is commonly described by in vitro test results such as bond strength and microleakage data. Due to the inconsistency often found between in vitro testing and in vivo performance, the purpose of the present investigation was to restore teeth scheduled for extraction in vivo with an experimental restorative bonding system and to evaluate the microleakage of the restorations by common laboratory techniques following extraction after 3 months of clinical service. Two restorations were placed in each of seven anterior teeth, one in the middle of the labial enamel portion and the other labially extending over the cementoenamel junction (CEJ). Six of the seven fillings completely surrounded by enamel showed no microleakage. However, two of the restorations crossing the CEJ revealed microleakage originating from the cervical margins. In spite of the small number of fillings assessed, the experimental enamel-dentin adhesive compound tested is preliminarily considered a promising new system.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1992

Effects of graded hypotension on cerebral blood flow, blood volume, and mean transit time in dogs.

This study tested the hypothesis that cerebral blood flow (CBF) is maintained by vasodilation, which manifests itself as a progressive increase in mean transit time (MTT) and cerebral blood volume (CBV) when cerebral perfusion pressure is reduced. Cerebral perfusion pressure was decreased in 10 pentobarbital-anesthetized dogs by controlled hemorrhage. Microsphere-determined CBF was autoregulated in all tested cerebral regions over the 40- to 130-mmHg cerebral perfusion pressure range but decreased by 50% at approximately 30 mmHg. MTT and CBV progressively and proportionately increased in the right parietal cerebral cortex over the 40- to 130-mmHg cerebral perfusion pressure range. Total hemoglobin content (Hb1), measured in the same area by an optical method, increased in parallel with the increases in CBV computed as the (CBF.MTT) product. At 30 mmHg cerebral perfusion pressure, CBV and Hb were still increased and MTT was disproportionately lengthened (690% of control). We conclude that within the autoregulatory range, CBF constancy is maintained by both increased CBV and MTT. Outside the autoregulatory range, substantial prolongation of the MTT occurs. When CBV is maximal, further reductions in cerebral perfusion pressure produce disproportionate increases in MTT that signal the loss of cerebral vascular dilatory hemodynamic reserve.

Animals↗
PubMed1992

[The short- and long-term results in heart surgery of the elderly].

We have studied retrospectively 106 patients aged 69 years or older (range 69 to 79) who underwent cardiac surgery between November 1986 and December 1989. The majority of patients (61%) were male. Coronary artery bypass surgery was performed in 59 patients, isolated valve replacement in 38 and combined valve replacement with coronary artery bypass surgery in 5. Two patients underwent ascending aorta replacement for aortic dissection and 2 ventricular aneurysmectomy and postinfarction ventricular septal defect repair. The mean postoperative hospital stay was 12 days. Ninety-one percent of patients underwent a primary elective operation and 9% required an emergency operation. Hospital mortality was 5% (n = 6). All hospital survivors were followed up by telephone contact (mean follow-up: 37 months) to determine presence or absence of chest pain, dyspnea, postoperative NYHA class and the overall effect of surgery on quality of life. There were 16 follow-up deaths; 5 were non cardiac. Follow-up study showed significant improvement in symptom status and quality of life (96%). We concluded that cardiac surgery in the elderly, although associated with increased operative risk, gives excellent relief of symptoms and good survival.

Aged↗
PubMed1992

The response of pregnant gilts previously given an inactivated preparation of porcine parvovirus (PPV) to challenge infection with a fully virulent PPV.

Eight 40-day pregnant gilts, previously treated with an adjuvanted-inactivated viral preparation (AIVP) obtained with a field strain of porcine parvovirus (PPV) together with 4 pregnant untreated controls, were subjected to challenge infection with a virulent strain of PPV at the 40th day of gestation. After challenge, all controls became febrile for 2 to 8 days, whereas only one gilt among those which had been treated with the AIVP experienced fever which lasted 4 days. Virus was consistently recovered from fecal swabs obtained from the controls and only sporadically from feces of AIVP-treated gilts. When the gilts were killed 53 days after challenge infection, no macroscopic lesions were found in any of the gilts in either groups, but fetal death was observed in the two groups of animals. However, the rate of dead fetuses was much higher among the control (70.5%) than among those from the AIVP-treated gilts (10.1%). Virus was recovered from 23 of the 24 dead fetuses in the control group and only from 3 among the 8 dead fetuses which were reported for the AIVP-treated gilts.

Acrylic Resins↗
PubMed1992

Measurement of enamel thickness in relation to reduction for etched laminate veneers.

The etched porcelain laminate veneer is a new conservative treatment that offers a solution to fractured, discolored, and worn anterior teeth. Preparation of enamel should be 0.5 mm to give minimal porcelain thickness and to avoid an overcontoured restoration. At the same time, dentinal exposure is contraindicated, because resin bonds better with enamel than with dentin. One hundred fourteen extracted teeth were measured at the gingival, middle, and incisal thirds. The resulting data reported on labial enamel thickness of anterior teeth may offer guidance in the preparation of laminate veneers.

Acid Etching, Dental↗
PubMed1992

Cement thickness and microleakage under metal-ceramic restorations with a facial butted margin: an in vivo investigation.

Ten metal-ceramic restorations with buccal porcelain butt margins and palatal metal beveled margins were fabricated for periodontally hopeless teeth. After cementation, the experimental crowns remained in the oral environment for 3 to 6 months; the teeth were then extracted and used for microscopic and microleakage evaluation. All ten crowns showed at least a small amount of microleakage, but adaptation of beveled margins proved to be superior to that of shoulder porcelain margins.

Cementation↗
PubMed1991

Plateletpheresis with the new Fresenius AS 104 blood cell separator.

Among the many blood cell separators introduced into the international market in these last few years, the Fresenius AS 104 represents an advanced and safe thrombocytapheresis machine whose development took advantage of extensive worldwide experience with blood cell separation. Nonetheless the AS 104 has generated most interest in West Germany and most, if not all, the studies published on its platelet collection efficiency have been carried out in that country. It is normally reported that from 2.7 to 3.5 x 10(11) platelets can be collected in approximately 80 minutes. Since these results could not be duplicated routinely in our hemapheresis unit, we set up a study by modifying the standard procedure. It was possible to reduce the procedure time and to collect platelet concentrates containing more than 4 x 10(11) cells on a routine basis by using the following procedure: ACD-A/blood ratio 1:10; Interface position 6:2; blood flow rate always exceeding 65 mL/min; rpm 1750; cell collection from 4 to 7 mL/min; volume of blood processed 3.6 L followed by the rinsing of the system with 200 ml of saline; extraction of the content of the secondary separation chamber by the action of the plasma pump working at 20 mL/min for 2 min. With this procedure the platelet yield in 34 collections exceeded 3.1 x 10(11) and averaged 4.06 x 10(11). The procedure time was reduced to 56.5 minutes with a mean blood flow rate of 62.3 mL/min. The leukocyte and erythrocyte contamination of the products were in the range of 1 x 10(7) and 1 x 10(8) respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation Studies as Topic↗
PubMed1991

Doxorubicin for acromegaly: a case report.

We report the case of an acromegalic woman, aged 35 years, with a huge GH-secreting tumor, repeatedly treated with neurosurgery and radiotherapy, not responsive to bromocriptine (Br) and octreotide (SMS), whose clinical picture evolved to coma due to endocranic hypertension. Since remnant size was too large to be further treated by surgery, chemotherapy with doxorubicin (DOX) (100 mg i.v. every three weeks up to 0.5 mg/m2 over 7 months) was started. Treatment was followed by a rapid improvement of clinical picture with resumption out of coma, progressive decline of GH levels (from 800 ng/ml to 15 ng/ml) and a slight shrinkage of tumor. No side effects were observed during DOX administration. We suggest that in those few acromegalic patients resistant both to SMS and Br, and with poor prognosis, DOX may be effectively used.

Acromegaly↗
PubMed1991

The vaccination and challenge with bovine viral diarrhea virus (BVDV) of calves previously infected with a non-cytopathic BVDV.

Four calves were infected with noncytopathic (NCP) New York-1 strain of bovine viral diarrhea virus (BVDV). During the observation period of one month the calves remained clinically normal but the virus was repeatedly recovered from their pharyngeal swabbings and blood. Thirty days following infection the four calves were vaccinated, together with two uninfected calves, with a modified-live vaccine containing cytopathic (CP) BVDV, infectious bovine rhinotracheitis virus and parainfluenza-3 virus. No detrimental effects were observed after vaccination. Forty-three days after vaccination the calves were challenged by exposure either with the CP TVM-2 strain or the NCP New York-1 strain of BVDV. The vaccinated calves remained healthy throughout the 60-day observation period.

Animals↗