[Cognitive research about the use of virtual worlds among the students enrolled to the faculty of medicine and surgery "Campus Bio-Medico University" in Rome]. / Indagine conoscitiva riguardo l'utilizzo dei mondi virtuali tra gli studenti della Facoltà di Medicina e Chirurgia dell'Università Campus Biomedico di Roma.

BACKGROUND AND AIMS: The main difference between a virtual reality and a generic representation is to be directly involved into the action you are performing. As a matter of fact, within the shift from real to virtual world, our biological physique does not mutate but is amplified and connected to the virtual world by technological interfaces. Training using a virtual reality simulator is an option to supplement (or replace) standard training. One of the two main goals of our study is to test, at first, how much students enrolled to the Faculty of Medicine at "University Campus Bio-Medico of Rome" are familiar with synthetic worlds, how long they have been using them and how they would like their Avatar to look like. Moreover, the second aim is to collect students' opinion about the use of virtual, interactive environments to enable learning and participation in dynamic, problem based, clinical, virtual simulations. Simulations might be used to allow learners to make mistakes safely in lieu of real life situations, learn from those mistakes and ultimately to improve performances by subsequent avoidance of those mistakes. MATERIALS AND METHODS: The selected approach to the study is based on a semi-structured questionnaire made of 14 questions administered to all the medical students. RESULTS: Most of the students appear not to be very confident with virtual worlds mostly because of a lack of interest. However, a large majority of them are likely to use a virtual world for fun or escaping from reality. Students would select and customize their Avatar by giving her/him the same sexual identity, same figure, same social class but different employment. CONCLUSIONS: It is important to notice that a wide majority of the students is interested in practicing on a virtual world in order to manage new experiences and being able to face them; their willing is to get benefits from the ability to make mistakes in a safe environment as well as to record a positive impact on their understanding.

Grayscale calibration and quality assurance of diagnostic monitors in a PACS system.

PURPOSE: The aim of this study was to calibrate monitors used in soft-copy review of diagnostic images in a pictures archiving and communication system (PACS) and to assess critical quality assurance (QA) parameters through appropriate checks. MATERIALS AND METHODS: Barco [cathode ray tube (CRT) and liquid crystal display (LCD)] and EIZO (LCD) monitors were evaluated. Calibration and QA controls were carried out during acceptance tests on the systems and every 6 months according to the Task Group 18 (TG18) report by the American Association of Physicists in Medicine (AAPM). The parameters in question include: maximum luminance, contrast ratio, luminance response, spatial resolution and angular response. A subjective evaluation of image quality was also conducted by a number of radiologists. RESULTS: Barco medical monitors' results were well within tolerances, with significant parameters persisting over time. EIZO nonmedical monitors showed rapid performance deterioration below the minimum requirements. Calibration had to be repeated only in a few cases. Radiologists' evaluations showed that monitor quality is equal to or even better than that of conventional films. CONCLUSIONS: Medical monitors turned out to be fully adequate to the task. Periodic QA tests are, however, absolutely necessary to ensure constant quality levels.

Comparison of reticulated platelet count and mean platelet volume determination in the evaluation of bone marrow recovery after aplastic chemotherapy.

Reticulated platelet count provides an estimate of thrombopoiesis in the same way as reticulocyte count is a measure of erythropoiesis. We applied thiazole orange (TO) staining, followed by fluorescence-activated flow-cytometric analysis, to platelets in whole-blood samples from normal subjects and 18 aplastic patients after chemotherapy for haematologic malignancies. The percentage of TO-positive platelets in 30 control subjects was 5.7 +/- 2.4% (mean +/- 1 SD), determining the threshold of reticulated platelet positivity as up to 10.5% (mean + 2 SD). In the 18 patients studied, the mean percentage of TO-positive platelets was 4.3 +/- 1.89% during aplasia and 23.3 +/- 9.43% during bone marrow recovery, respectively (P < 0.05). All patients had a percentage of TO-positive platelets of up to 10.5%. In comparison, mean platelet volume during bone marrow recovery increased in 12 cases of the 18 patients studied. We conclude that flow cytometric analysis of reticulated platelets is a sensitive and specific test for evaluating thrombopoiesis recovery during aplastic chemotherapy, and platelet transfusion should be reconsidered in these patients.

[Assessment of contrast enhancement in solitary pulmonary nodules studied with spiral computerized tomography. Preliminary results]. / Valutazione dell'accentuazione del contrasto del nodulo polmonare solitario studiato con Tomografia Computerizzata spirale. Risultati preliminari.

This study was aimed at assessing the clinical usefulness of measuring the contrast enhancement (CE) of solitary pulmonary nodules (SPN) in distinguishing benign from malignant lesions. We used spiral CT to study prospectively 35 pulmonary lesions presenting as SPNs < 30 mm phi; we evaluated the CE of the nodules 120 minutes after the administration of 100 mL of nonionic contrast material (= 30 grams of iodine), at 2 mL/s. The final diagnosis of the 35 SPNs was made at surgery (27 cases); positive sputum cytology (2 cases), 12 months' follow-up (5 cases) or fine-needle aspiration biopsy and 6 months' follow-up (1 case). Thus, 25 of 35 SPNs proved malignant (11 adenocarcinomas, 5 squamous cell carcinoma, 2 large cell carcinomas, 2 carcinoids, 1 small cell carcinoma, 2 cases with positive sputum cytology, 2 metastases) and the extant 10 of 35 proved benign. Malignant nodules enhanced markedly more (mean value: 36.8 HU) more than benign lesions (mean value: 18.6 HU). CE exceeded 20 HU in 23/25 malignant nodules and did not in 2/25; it did not exceed 20 HU in 6/10 benign nodules and did in 4/10. With 20 HU as the threshold value for a positive test (malignancy), sensitivity was 92%, specificity 60% and accuracy 83%; positive and negative predictive values were 85% and 75%, respectively. In conclusion, CE evaluation is a sensitive, although not very specific, indicator of malignancy in SPNs.

[The detectability of osteoarticular lesions of the extremities on the television monitor]. / Riconoscibilità delle lesioni osteoarticolari delle estremità al monitor televisivo.

The diagnostic accuracy of the light-box reading of conventional (film screen) radiographs of the extremities was compared with that of the same set of images displayed on a 1 k x 1 k interactive monitor after laser digitization. 389 alterations (23 nondisplaced fractures, 129 soft-tissue calcifications and 237 articular bone erosions), identified by two experienced radiologists on 66 conventional radiographs, were the reference standard. ROC statistical analysis was performed on 1,556 observations expressed by four readers. The overall diagnostic performance of the two display modalities were substantially equivalent: no statistically significant differences resulted on the whole, but two individual readers performed better with conventional images. No overall nor individual statistically significant difference was reobserved for the subset of articular erosions either. Light-box reading of conventional radiographs allowed a higher number of calcifications in the soft-tissues and of proximal (carpal) abnormalities to be detected. Although our results indicate the overall high fidelity of monitor-displayed laser-digitized images, major improvements in the performance of digital diagnostic workstations are still required before adopting monitors for routine radiologic activity.

Hemorrhagic infarction: risk factors, clinical and tomographic features, and outcome. A case-control study.

A radiological diagnosis of hemorrhagic infarction (HI) was made in 41 of 2726 cases with cerebrovascular lesions (1.9%). The clinical records of the cases and those of 82 age- and gender-matched subjects with ischemic infarction were examined, and notes of the principal risk factors of cerebrovascular disorders, the clinico-radiologic features and the outcome of the disease were taken for comparison. Cardiac sources of emboli (atrial fibrillation, native or prosthetic valve disorders, recent myocardial infarction) were present in 44% of cases and in 24% of controls. Diabetes mellitus was recorded in 31% and 18% respectively. Thirteen percent of cases and 35% of controls gave a history of transient ischemic attacks. Stupor or coma during the acute phase and a more severe course were more common among cases. In general, HIs were significantly larger than ischemic infarcts, with mass-effect, although the size of the lesion did not seem to be related to the presence of cardiogenic embolism.

A radiologic study by CT scan of pineal size in cancer patients: correlation to melatonin blood levels.

Alterations in size of the pineal body and melatonin secretion have been observed in cancer patients. The present study was carried out to evaluate pineal dimensions in a group of cancer patients and their relation to melatonin blood levels. The study included 70 oncologic patients. As controls, 41 patients with acute or chronic disease other than cancer entered the study. Melatonin serum levels were measured by radioimmunoassay on venous blood samples collected at 9:00 a.m. Pineal size was determined by brain CT scan, by considering the product of the two longest perpendicular diameters, multiplied by the thickness of the stratum. The volume of the pineal body was found to be enlarged in 12/70 (17%) cancer patients, and its mean value was significantly higher than that observed in controls. Melatonin levels were also significantly higher in oncologic patients than in controls. However, there was no correlation between melatonin levels and pineal size in cancer patients. Finally, cancer patients did not show a higher degree of pineal calcifications than controls. The clinical significance of pineal enlargement in cancer patients remains to be understood.

Cranial computed tomography findings in children with acute lymphoblastic leukemia at diagnosis.

Forty children newly diagnosed with acute lymphoblastic leukemia (ALL) were examined by computed tomography (CT) of the central nervous system (CNS) on hospital admission before any medication was started. The results of the CT scans were defined as normal, borderline (slight or moderate dilatation of the ventricular system and/or basal cisterns and/or convolutional sulci), or pathologic (severe cerebral atrophy). The mean age of the patients was 5.8 years (range 1.7-15 years). Sixteen of the 40 patients (40%) had CT scan abnormalities with 14 patients having borderline scans and two patients pathologic scans. No child presented with neurologic symptoms or CNS leukemia. These data suggest that CT abnormalities of the brain are common in children with ALL at diagnosis and may represent clinically unsuspected lesions secondary to leukemia.

[Teleradiography and tomography in the search for pulmonary metastases in 132 cases of soft tissue and bone neoplasms]. / Teleradiografia e tomografia nella ricerca delle metastasi polmonari in 132 casi di neoplasie delle parti molli e delle ossa.

In recent years whole lung tomography (WLT) has been considered mandatory in the staging of some neoplastic diseases, particularly of soft tissues and bone tumors. Since WLT is an exacting roentgen examination, its usefulness was evaluated by analysing 132 consecutive patients submitted to orthogonal chest roentgenograms and WLT, from January 1979 to October 1981 at the National Cancer Institute of Milan. A comparison between WLT and traditional chest X-ray examination was performed in order to evaluate how much tomography is significantly useful in improving diagnosis of lung metastases. From this analysis, the authors conclude that WLT is generally unnecessary when chest roentgenograms are negative, whereas it is useful when single or multiple lung metastases are already evident by traditional X-ray examination. In these cases WLT allows a more accurate identification of the metastases from the point of view of their number and site, which is important not only for the treatment choice but also for the check of its effectiveness.

Comparison of endocrine secretion by monolayer cultures derived by different procedures from neonatal hamster and rat pancreas.

Monolayer cultures derived from neonatal hamster or rat pancreas by two different epithelioid cell-enriching gravity sedimentation procedures varied in ability to maintain uniform levels of insulin secretion with increased culture age. Rat pancreatic cultures were superior in this respect to identically derived hamster preparations, depending on the preparative procedure employed. Quantitative differences in the temporal pattern of insulin secretion by different rat pancreatic culture preparations were ascribed to plating cell density and consequent terminal cell density as a function of preparative procedure such that reduced densities favored sustained secretory levels. These findings suggest the importance of tissue species and preparative procedure in deriving pancreatic monolayer cultures capable of sustained levels of insulin secretion with age.

Hyaluronidase-induced inhibition of the insulinotropic action of sulfonylureas, leucine, and glucagon in rodent isolated pancreatic islets.

Exposure of hamster pancreatic islets to hyaluronidase during isolation by means of collagenase inhibits the insulinotropic action of several chemically different sulfonylureas, leucine, and glucagon without affecting glucose-stimulated insulin secretion. This inhibition is reversible for tolbutamide and leucine but irreversible for glucagon. Hyaluronidase inhibits reversibly the insulinotropic action of tolbutamide without affecting that of glucose also in mouse and rat isolated pancreatic islets . These findings suggest the existence of functionally related pancreatic beta cell receptors for tolbutamide and leucine different from those for glucose and glucagon and illustrate the potential usefulness of hyaluronidase as an enzymatic probe applicable toward investigating the cellular mechanism of action of key insulinotropic agents.

Monolayer cultures derived from neonatal hamster pancreas. Light and electron microscopy.

Cells derived by trypsinization of neonatal golden hamster pancreas were cultured in modified Eagle's medium for 120 h in the presence of glucose (0.8 mg/ml) and for an additional 48 h in medium containing glucose (0.8 or 3.1 mg/ml) or tolbutamide (1,000 microg/ml) plus glucose (0.8 mg/ml). At day 7, cultures were stained differentially for light microscopy or examined by electron microscopy. Immunoreactive insulin (IRI) and immunoreactive glucagon (IRG) in the culture medium were measured by standard immunoassay procedures. Staining properties and ultrastructural appearance of cultured cells were comparable to those of the intact neonatal hamster pancreas. Cultures consisted predominantly of cells possessing aldehyde fuchsin positive (AF(+)) cytoplasmic granules resembling ultrastructurally those of the intact neonatal pancreatic beta cells and additionally, those of fibroblastoid, acinar, acino-insular, and aldehyde fuchsin negative (AF(-)) argyrophilic cells. IRI release rate by the cultured cells was increased in the presence of elevated glucose or tolbutamide which paralleled the loss of AF(+) granulation, but IRG release rate was suppressed by elevated glucose concentration. These findings indicate that these monolayer cultures consist of most of the cell types occurring in the neonatal pancreas, including endocrinologically competent islet cells.