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Biomedical subjects

G Montanari

Publications and source records attributed to G Montanari.

At least 37 records · Page 2Linked to original sources
PubMed1996

[The evaluation of the physical characteristics of a volumetric computer tomograph].

Spiral or volumetric computed tomography (CT) is a new scanning technique which allows the scanning of body regions with a continuously rotating system based on the slip ring technology; the patient is also moved continuously, synchronously with data acquisition. The physical characteristics of spiral CT image acquisition were compared with those of conventional CT images. The modulation transfer function (MTF) has the same values for medium-resolution filters, but lower values for spiral CT for high-resolution and frequency-enhancement filters. The slice sensitivity profile (SSP) describes the longitudinal image resolution for multiplanar reconstructions and was measured in terms of FWHM of the SSP curve. We obtained, for 10-mm slice thickness, a FWHM = 10.4 mm (conventional CT), versus 10.7 mm (Spiral CT), while, for 5-mm slice thickness, the corresponding values were 5.2 mm (conventional CT) and 5.5 mm (spiral CT). Noise was evaluated simply by measuring the standard deviation of the CT numbers, in a region of interest, of a uniform image and with the power spectrum or Wiener spectrum of the same image. To assess overall image quality and yield, the noise equivalent quanta (NEQ) value was also calculated. The values were a little lower for the spiral technique, particularly with high-resolution and enhancement or convolution filters. Dosimetric evaluation of the computed tomography dose index (CTDI) and of the multiple scan average dose (MSAD) was done using an acquisition protocol for average lung dose, in an anthropomorphic phantom and with TL dosimeters. The MSAD was 6.17 +/- 0.20 cGy for conventional CT and 5.98 +/- 0.23 cGy for Spiral CT, while lung dose was 3.25 +/- 0.12 cGy and 3.01 +/- 0.16 cGy, respectively.

Artifacts↗
PubMed1995

Efficacy of a three day course of azithromycin in moderately severe community-acquired pneumonia.

This study was designed to evaluate the efficacy of a 3 day course of azithromycin in low to moderately severe community-acquired pneumonia. Forty patients with low to moderately severe community-acquired pneumonia (29 males, 11 females, mean age 46 +/- 17 yrs; 20 pretreated with betalactams for 2-10 days with no results before admission to hospital; 18 with evidence of co-morbidity) were enrolled in an open, randomized study with azithromycin, 500 mg q.d. oral therapy for 3 days, versus clarithromycin, 250 mg b.i.d. oral therapy for 10 +/- 2 days. The aetiology of pneumonia was identified in 18 patients by serology (nine Mycoplasma pneumoniae, four Chlamydia pneumoniae, five Legionella pneumophila; one patient with chlamydial infection also had Klebsiella pneumoniae bacteraemia). A presumptive aetiological diagnosis was obtained with sputum culture in three other patients (one Haemophilus influenzae, two Haemophilus parainfluenzae), all strains were sole isolates with 10(8) Colony forming units (CFU), and with Gram stain in one patient with Streptococcus pneumoniae. All patients in the azithromycin group (one after a second 3 day course), and all but two (of those available for evaluation) of the clarithromycin group were cured. Defervescence occurred after 2.6 +/- 1.6 days, and chest roentgenogram cleared after 8.9 +/- 3.3 days, with no difference between the two groups. Tolerance was good, and there were no withdrawals from therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Selective trophic effect of L-carnitine in type I and IIa skeletal muscle fibers.

Biopsies were taken from the vastus lateralis muscle of 26 chronic uremic patients before and after a 24-week treatment with L-carnitine given at the dose of 2 g i.v. at the end of hemodialysis, or in dialysis solution, or per os twice daily. The aim of the study was to evaluate both the muscle morphology in dialyzed subjects and the modification provoked by the therapy. All patients manifested a significant, even if variable, degree of muscular atrophy which involved all types of muscle fibers. After the treatment there was an increase of about 7% in the diameter of type I and type IIa fibers, which can utilize carnitine for fatty acid oxidation to produce energy, and a reduction in the atrophic fibers. No noteworthy changes were documented in type IIb fibers, which depend on glycolysis for energy production.

Carnitine↗
PubMed1994

Composite resin-amalgam compound restorations.

Extensive silver amalgam restorations in premolars and molars occasionally require sacrifice of healthy unsupported enamel walls or cusps. A posterior composite resin-amalgam compound technique has been proposed to conserve these structures. Microleakage was high at the enamel-amalgam interface, moderate at the composite resin-silver amalgam and dentin-composite resin interfaces, and minimal between the inner enamel and the composite resin. Light microscopy and scanning electron microscopy demonstrated that marginal adaptation of the silver amalgam to the composite resin of the cusps was acceptable and that penetration of the inner etched enamel to the composite resin was complete.

Bicuspid↗
PubMed1994

[Propafenone and verapamil poisoning. Report of 2 clinical cases].

We described the self-poisoning of two young adolescents who took improper doses of two major cardiovascular drugs: propafenone and verapamil. The young girls developed markedly different clinical patterns: ECG abnormalities without clinical consequences were found in one case progressively ingravescent ECG abnormalities leading to cardiac arrest in the other. These differences are probably due to varying doses taken and metabolic states. Conventional detoxication and resuscitation techniques proved successful in both cases.

Adolescent↗
PubMed1994

[Digital storage phosphor radiography. Doses and image quality].

Digital radiography (DR) based on storage phosphor technology is progressively replacing conventional screen-film system radiographic techniques (CR). However, many questions about image quality and dose reduction are still open. Thus, since DR spatial resolution is always lower than that of high quality screen-film images and image noise is conversely higher, for general radiography examinations especially, the signal-to-noise ratio is always lower with DR than with CR at the same dose level. However, the wide dynamic range, the linear response of storage phosphor detectors and the automatic read-out control of the digital system, enable lower DR X-ray imaging efficiency to be overcome, producing a nearly perfect readout of the image data every time an exposure is made. Moreover, post-processing can make the detection of abnormalities easier. This is why in many ROC clinical accuracy studies DR performed equally or better than CR. Good quality DR images, similar to conventional ones at the same dose levels, are therefore achievable in chest, abdomen, bone and soft-tissues examinations. Dose evaluation protocols are strongly needed in DR since overexposures due to technical mistakes may be overlooked; moreover, doses can be adjusted to the peculiar diagnostic need. The S values shown on any hard-copy image can be used to this purpose, even though it must be pointed out that they do not express the actual mean dose to the detector.

Humans↗
PubMed1992

Respiratory chain enzymes in muscle of endurance athletes: effect of L-carnitine.

The effects of L-carnitine on respiratory chain enzymes in muscle of long distance runners were studied in 14 athletes. These subjects received placebo or L-carnitine (2 g orally b.i.d.) during a 4-week period of training. Athletes receiving L-carnitine showed a significant increase (p < 0.01) in the activities of rotenone-sensitive NADH cytochrome c reductase, succinate cytochrome c reductase and cytochrome oxidase. In contrast, succinate dehydrogenase and citrate synthase were unchanged. No significant changes were observed after placebo administration. The levels of both total and free carnitine from athletes receiving placebo were significantly decreased (p < 0.01) after treatment. By contrast, total and free carnitine levels were markedly increased (p < 0.01) after supplementation with L-carnitine. Our results suggest that L-carnitine induces an increase of the respiratory chain enzyme activities in muscle, probably by mechanisms involving mitochondrial DNA.

Analysis of Variance↗
PubMed1992

Effects of dentin surface treatments on the shear bond strength of Vitrabond.

The influences of nine dentin surface treatments were evaluated on the shear bond strength of a new light-cured glass-ionomer cement (GIC) and on the SEM morphology of the treated dentin surfaces. The following treatments were performed: saline solution (control), NaOCl, acidic glycine, EDTA, malic acid, malic acid plus glycine, polyacrylic acid, tannic acid, and neutral+acidic oxalate solutions. Buccal dentin surfaces were polished with #320-grit abrasive paper, treated with one of the chemicals, washed, and air-dried. Cylindrical GIC samples were then applied to the dentin surface, stored in 100% humidity, and tested after 24 h. SEM observations demonstrated no effect of saline or NaOCl treatment on the smear layer but its complete removal with exposure of collagen fibrils after malic or malic acid plus glycine treatment. Partial removal of the smear layer occurred following glycine treatment and with tannic or polyacrylic acids. Complete removal of the smear layer was seen after EDTA or pyruvic acid treatment. Oxalate treatment produced a layer of crystals, which completely covered the dentin surface. Shear bond strength of GIC was significantly increased only by treatment with the oxalate solutions.

Dental Bonding↗
PubMed1992

Lateral discoid meniscus: treatment and results.

Forty-six patients (47 knees) who had symptomatic discoid lateral menisci were operated on between August 1981 and May 1989. The patients were categorized according to Watanabe's classifications: complete (80.8%), incomplete (10.6%), and Wrisberg type (8.5%). The treatment of the discoid meniscus is based on total or partial meniscectomy, achieved by the percutaneous or arthrometric technique. Of the 47 knees, 30 underwent a follow-up evaluation. Using Ikeuchi's knee scale, 27 cases (90%) had either excellent or good ratings, and 3 (10%) received fair ratings. There were no poor outcomes. The results in the knees treated by partial meniscectomy were better than those in the knees treated with total meniscectomy.

Adolescent↗
PubMed1992

Treatment with low dose metformin in patients with peripheral vascular disease.

Low dose metformin (500 mg b.i.d.) was tested in 11 patients with symptomatic peripheral vascular disease (PVD) in an open design. At -1, 0, 1, 4, 7 months the major lipid and lipoprotein parameters, arterial function, and fibrinolytic activity were monitored. Arterial function changes were similar to those found with a high dose (850 mg t.i.d.) metformin but plasma lipids did not change to an appreciable extent. Post-ischaemic blood flow, by plethysmography, rose 30%; the exercise capacity, evaluated by treadmill test, also increased significantly by 105.7% for relative and 53.3% for absolute claudication. Total fibrinolytic activity did not change during the treatment but the antigens of two of the major components of the fibrinolytic system, i.e. t-PA and PAI-1, were significantly reduced at the end of the study. This study gave results quite consistent with those obtained with higher metformin doses, associated with a potentially higher risk of lactic acidosis.

Aged↗
PubMed1992

[Gynecomastia].

Gynecomastia is a benign pathology due to the increased volume of the mammary glands. The various etiological factors lead to an imbalanced estrogen/androgen ratio or to a greater local receptivity to the former with consequent hypertrophy of the mammary stromal gland components. Although the majority of cases are benign and/or transient, gynecomastia must be carefully examined using thorough anamnesis, hormone assays and instrumental tests in order to exclude local or further removed pathology. At present, medical or surgical therapy is reserved for those cases in which this condition is painful and/or psychologically damaging. In this study, following a review of the literature, the Authors focus on the etiological, diagnostic and therapeutic aspects of gynecomastia and illustrate the cases they have observed.

Adolescent↗
PubMed1992

[Intestinal volvulus in pregnancy].

Intestinal occlusion is a rare pathologic event during pregnancy occurring mostly in the second and third trimenon when increased volume of the uterus and the consequent displacement of abdominal organs cause complications of pathologies which would otherwise escape notice, such as intestinal adhesions, to become manifest. Diagnosis is difficult for a number of reasons. Vomiting during the first trimenon and mild abdominal pain during the third are often neglected or considered to be part of the normal course of pregnancy; pain is sometimes referred to atypical sites due to the displacement of abdominal organs; in other cases, the high endorphin tonus is apt to reduce the customary defence reaction. All this should not cause time to be lost, and whenever intestinal occlusion is suspected all the necessary diagnostic procedures must at once be carried out and appropriate therapy must speedily be started so as to reduce the risk of mortality and morbidity for mother and fetus. Management of ileus in pregnancy is identical to that for the non pregnant woman, except for the need to empty the uterus in cases in which it prevents treatment or if the fetus has reached a sufficient degree of pulmonary maturity. The paper describes a case of ileal volvulus and revisits the literature analyzing the diagnostic and therapeutic options suggested.

Adult↗
PubMed1992

[Ultrasonography and ultrasound-guided biopsy in lymphomas].

The authors have reviewed the literature on imaging techniques for the diagnosis of lymphoma. Lymphography, axial computerized tomography (CT) and echotomography have been compared as to their sensitivity and specificity. Lymphography allows diagnosis of the disease even in lymph nodes of less than 0.5 cm diameter, but this technique cannot be applied to all lymphatic station. Echotomography and CT are equivalent as to the accuracy of diagnosis and are both helpful for guided needle biopsy. In view of its low cost, echotomography is considered by most workers the first-line approach to the evaluation of lymphoma patients. In spite of its advantages over other methods, echotomography must, nevertheless, be integrated by CT, lymphography, and nuclear magnetic resonance.

Biopsy↗
PubMed1991

[Diagnosis of breast carcinoma. Comparison of clinical, mammographic, echographic and cytological aspiration diagnosis in a group of 50 patients].

The study assesses the sensitivity of clinical, mammographic, echographic and needle biopsy tests in a sample group of 50 women some of whom were examined and operated by the Surgical Division of Casalpusterlengo Hospital, whereas others were examined and operated at Crema Hospital. Data were compared with those from larger studies recently reported in the literature. Patients had a minimum age of 42 years and a mean age of 64.3 years; all were symptomatic. Clinical examination, mammography and echotomography showed an increased sensitivity in parallel with the increased size of tumour and the patient's age. The sensitivity of mammography in T1 cases was higher than that of clinical examination and ultrasound tests. Diagnosis was made on cytological grounds alone in 2% of cases, but was negative in 14% (benign/inadequate sample) in spite of the presence of a positive clinical examination and mammography. A 90.4% sensitivity rate was achieved using a combined clinical examination and mammography.

Adult↗
PubMed1991

Shear bond strength and microleakage of dentin bonding systems.

This study evaluated the shear bond strength and microleakage of class V non-retentive restorations with 10 different dentin bonding systems. Some were tested with different composite resins. For the shear bond test, eight specimens were prepared for each product and tested in a universal testing machine. For the microleakage test, 158 V-shaped class V cavities extending to the cementoenamel junction were prepared, coated with a dentin bonding system, and restored with a composite resin. After 250 thermocycles, the teeth were immersed in a dye solution for 48 hours, longitudinally sectioned, and evaluated for microleakage. Both test procedures resulted in significant differences between the various materials. The bond strength failed to completely prevent microleakage at the dentinal wall. The new generation of dentin bonding systems offer a significant improvement over previous materials.

Acrylates↗