High-rate x-ray spectroscopy in mammography with a CdTe detector: a digital pulse processing approach.

PURPOSE: Direct measurement of mammographic x-ray spectra under clinical conditions is a difficult task due to the high fluence rate of the x-ray beams as well as the limits in the development of high resolution detection systems in a high counting rate environment. In this work we present a detection system, based on a CdTe detector and an innovative digital pulse processing (DPP) system, for high-rate x-ray spectroscopy in mammography. METHODS: The DPP system performs a digital pile-up inspection and a digital pulse height analysis of the detector signals, digitized through a 14-bit, 100 MHz digitizer, for x-ray spectroscopy even at high photon counting rates. We investigated on the response of the digital detection system both at low (150 cps) and at high photon counting rates (up to 500 kcps) by using monoenergetic x-ray sources and a nonclinical molybdenum anode x-ray tube. Clinical molybdenum x-ray spectrum measurements were also performed by using a pinhole collimator and a custom alignment device. RESULTS: The detection system shows excellent performance up to 512 kcps with an energy resolution of 4.08% FWHM at 22.1 keV. Despite the high photon counting rate (up to 453 kcps), the molybdenum x-ray spectra, measured under clinical conditions, are characterized by a low number of pile-up events. The agreement between the attenuation curves and the half value layer values, obtained from the measured spectra, simulated spectra, and from the exposure values directly measured with an ionization chamber, also shows the accuracy of the measurements. CONCLUSIONS: These results make the proposed detection system a very attractive tool for both laboratory research and advanced quality controls in mammography.

[The demonstration of the connection of cause in the professional allergic pathology not tabulated. Utility and limits of the allergometric tests]. / La dimostrazione del nesso di causa nella patologia allergica professionale non tabellata. Utilità e limiti dei test allergometrici.

The Sentences of the Constitutional Court no 179/88 and 206/88 have of done modified the system insurance of the professional illnesses. To the old tabular system to the pathologies for which the legal conceitedness of origin is in force they are added those pathologies that need to be shown with burden of test of the applicant. And necessary to resort to the criterion pathogenetic for the geneses pathologies plurifactorialy or to non certain etiology. These innovations determine the necessity of a methodological iter forced for the recognition of the professional illness not table. The authors therefore they propose an iter diagnostic that passes through the recognition of the connection of cause. To such intention the authors examine meaning and limits of the suggested investigations.

Feeding dysfunction in infants with severe chronic renal failure after long-term nasogastric tube feeding.

Nasogastric tube feeding (NGTF) is frequently necessary to overcome the inadequate caloric intake of children with severe chronic renal failure (CRF). In a multicenter retrospective study, we evaluated feeding dysfunction after tube feeding withdrawal in children with severe CRF who started long-term enteral nutrition early in childhood. We considered, almost exclusively, infants who had started NGTF very early and continued to be tube fed for at least 9 months. Twelve patients were included in the study: 8 showed significant and persistent eating difficulties, with difficulties in chewing and swallowing in 7 and food refusal in 6. For 2 patients "panic attacks" from swallowing were repeatedly reported. These problems persisted for more than year in 5 patients and between 1 and 6 months in 4. The possible feeding difficulties that may follow NTGF must be carefully evaluated. A possible means of overcoming these difficulties might include: encouraging the use of a pacifier, proposing water for spontaneous assumption, leaving the child the possibility of eating food spontaneously during the daytime, and increased support for the parents during weaning. These need prospective study.

Abnormal hypertensive response during exercise test in normotensive transplanted children and adolescents.

We investigated the cardiovascular and respiratory conditions, at rest and in response to stress testing, in 10 children and adolescents with successful renal transplantation, to release certifications for participation in sports. Our patients were aged more than 6 years, transplanted 6 months or more before the study, with creatinine clearance > 40 ml/min/1.73 m2, without hypertension at rest. All but 1 were on cyclosporine A, prednisone and azathioprine. Two control study groups with the same chronological age and body surface area were paired with our patients. They underwent a graded exercise tread-mill test, during which maximal blood pressure and heart rate were recorded. Resting electrocardiogram, dynamic 24-hour electrocardiogram Holter monitoring and mono- and bidimensional echocardiograms were obtained before the test. Spirometry was performed to study lung flow and volume. A questionnaire collected information about physical activity patterns. Four categories, according to practice, frequency and duration of exercise, were identified: nonactive, starters, experienced and very experienced. Most children and adolescents were sedentary or mildly interested in sports and during treadmill test we observed reduced exercise capacity and systolic hypertensive response to increasing exercise testing.

Risks of acute renal failure after cardiopulmonary bypass surgery in children: a retrospective 10-year case-control study.

To our knowledge there are no case-control studies that have examined the main risk factors for acute renal failure (ARF) following cardiopulmonary bypass surgery in children. We therefore evaluated the potential risk factors in a large retrospective case-control study. Sixty-one of 2262 children (2.7%) developed postcardiopulmonary bypass surgery ARF requiring peritoneal dialysis (PD) from 1982 to 1991. Fifty-eight of 61 cases (median age 8.5 months) were selected by systematic sampling and matched with 176 controls who did not develop ARF. The four matching variables were age, cardiopulmonary bypass and circulatory arrest duration, and year of operation. Mortality rate was 79% in cases (controls: 18%). Forty-three of 48 of the deceased cases did not recover renal function: no renal cause of death was found; 13 of 61 cases survived and recovered renal function. Multiple regression analysis showed the following significant risk factors for postcardiopulmonary bypass surgery ARF: central venous hypertension > 12 h (odds ratio (OR) 9.6); systolic arterial hypotension > 12 h (OR 8.9); dopamine dosage > 15 micrograms/kg/min (OR 3.0); adrenaline (OR 5.9) and isoproterenol (OR 13.5) use. High preoperative serum creatinine, cyanosis, and vasodilator use were not significant risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Haemolytic-uraemic syndrome in childhood: surveillance and case-control studies in Italy. Italian HUS Study Group.

Seventy-six cases of haemolytic-uraemic syndrome (HUS) were collected over a 4-year period during a surveillance and case-control study. The annual incidence of 0.2 per 100,000 children aged 0-14 years is lower than in other countries; 34% had no prodromal diarrhoea. Evidence for verocytotoxin-producing Escherichia coli (VTEC) infection was found in 72% of patients and 3% of controls; 88% of patients with bloody diarrhoea, 67% with non-bloody diarrhoea and 55% without diarrhoea were VTEC positive. Seventy-three percent of patients had creatinine clearance > or = 80 ml/min per 1.73 m2, normal blood pressure, no proteinuria and haematuria < 2+ after 1 year of follow-up. One patient died and none had non-renal sequelae. VTEC positivity was significantly correlated with a good outcome, while the absence of diarrhoea and a high total white blood cell count at onset were not predictors of a bad outcome. Household contacts of HUS patients had diarrhoea more frequently than those of the control group, supporting the hypothesis of person-to-person transmission of VTEC infection.

A community outbreak of haemolytic-uraemic syndrome in children occurring in a large area of northern Italy over a period of several months.

From March to October 1993, 15 cases of haemolytic-uraemic syndrome (HUS) in children were detected in a large area of northern Italy, where only 8 cases had occurred in the previous 5 years. Analysis of stool and serum specimens obtained from 14 cases showed evidence of Verotoxin-producing Escherichia coli (VTEC) infection in 13. Serum antibodies to the E. coli O157 lipopolysaccharide (LPS) were found in 8 patients and to the O111 LPS in 2. An O86 VTEC was isolated from another patient. Fourteen children needed dialysis, and 1 died. No obvious epidemiologic link was observed among cases, most of whom lived in small townships. A case-control study did not show an association between HUS and food or exposure to cattle, but suggested an association with contact with chicken coops (OR = 6.5, 95% C.I. 1.2-34.9). However, VTEC were not isolated from stool samples obtained from the chicken coops involved. The risk factors for VTEC infection related to living in rural settlements, including the exposure to live poultry, should be considered in outbreak investigations.

Effects of stress and conflict difficulty on arousal and conflict resolution.

The present study was concerned with the effects of conflict type and shock stress on arousal and conflict resolution. Subjects were randomly assigned to either stress (random shock) or non-stress conditions. Each subject was exposed to three trials of each of the four Lewinian conflict types and three control trials, interspersed among additional non-conflict trials. Resolution performance was assessed in terms of speed of resolution and error frequency. Phasic electrodermal responsivity served as a measure of arousal. Results supported several hypotheses. It was found that both stress and conflict increased the magnitude of electrodermal responses and that larger responses occurred under more difficult conflicts. In addition, increased conflict difficulty produced lower speeds, and stress increased errors. Finally, stress caused a greater increase in error frequency on conflict than on control trials. Results were discussed in terms of arousal and stress hypotheses found in the theories of Lewin and Dollard & Miller.