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Biomedical subjects

S Maggi

Publications and source records attributed to S Maggi.

At least 73 records · Page 4Linked to original sources
PubMed1993

[Physics, dosimetry, and quality control in mammography].

The diagnostic value of mammography, especially in the early diagnosis of breast cancer, is closely related to examination optimization in terms of high-quality images with the lowest possible dose to the organ. Currently, "optimal" beams are produced by X-ray tubes with a Molybdenum anode, their voltage reaching 35 kV, using the K fluorescence line at 17.48 keV and absorption of photons with > 20 keV energy, through Mo filtration. The dose delivered with a mammographic examination is expressed differently in the literature reports on the subject: air exposure, skin exposure, dose at the midplane and mean dose; currently, it is recommended to specify the dose as "average glandular tissue dose", considering beam quality and the ratio between transmissions in perspex and tissues respectively. Threshold values for the average dose to the glandular tissue range 1.8 to 3 mGy with a grid and 0.9 to 1.5 mGy without the grid. The high quality standard of mammography requires quality assurance programs including the mammographic unit and the image acquisition and treatment systems. In Italy the "Dose and Quality in Mammography" program is in progress. According to the acceptance quality criteria established in the program and on the basis of the investigation of 272 centers, an acceptable dose-quality ratio was seen in 37.5% of the centers, low quality was found in 24.5%, high dose in 23.7% and high dose plus low quality in 14.1% of the whole of centers.

Breast Neoplasms↗
PubMed1993

The need for a strict methodology in dietary surveys: the experience of the WHO Osteoporosis Project.

There are three basic dietary data collection tools: direct weighing, diet diaries and diet recalls. Each technique has inherent strengths and weaknesses. Direct weighing requires great cooperation from the participants, is expensive and time consuming; diary methods tend to distort usual intake patterns, while retrospective data collection methods are subject to respondent memory bias. Therefore, there are differences in study outcomes depending on the methodologies used; comparisons of data collected in different studies would only be possible if a standardized method were utilized. The Project on Osteoporosis of the World Health Organization is a cross-national study, designed to explore the differences in the incidence of hip fracture and to ascertain risk and protective factors for bone loss and fractures in the older populations in different countries. The objective of the diet assessment is to evaluate the role of diet on osteoporotic hip fracture, and on loss of bone mass. Major effort during the preparation of the proposal was devoted to the development of strategies for assessing the validity and reliability of the instruments selected and the comparability of the results obtained in the participating countries. Such strategies include re-interviews of the participants, proxy interviews and comparisons of data obtained by the food frequency method and those recorded in diaries.

Aged↗
PubMed1992

[Malignant fibrous histiocytoma of the pancreas].

The authors report a case of pancreatic malignant fibrous histiocytoma (approximately 22 cm). Clinical and instrumental approach for preoperative diagnosis is discussed and the anatomopathological features of the lesion, which is rarely localized in the pancreatic gland, are stressed. Surgical treatment is outlined as well.

Female↗
PubMed1992

[Use of ultrafiltration in refractory cardiac decompensation].

Traditional therapy for heart failure (diuretics, digitalic compound, vasodilators, inodilatory ACE-inhibitors) cannot arrest the progressive overloading of the circulatory system so that it is inevitable that a refractory stage to all forms of treatment will be reached when more specialised techniques, such as heart transplant and ultrafiltration will be needed. The paper reports the results obtained in 13 patients in ultrafiltration treatment for refractory heart failure: in the majority of these, a marked improvement in general conditions (edema, dyspnea) was recorded together with a regression from class 5 to class 3 NYHA in 5 patients, and to class 2 for others. The ultrafiltration method in spite of not altering the prognosis which remains negative in these patients, allow those waiting for heart transplant to survive and may improve their chances of surviving heart surgery.

Adult↗
PubMed1992

[Hormonal markers of early-stage osteitis fibrosa in patients on hemodialysis].

The diagnosis of renal osteodystrophy is straightforward when the disease has reached an advanced stage and the pathology is extremely difficult to treat, whereas it is considerably more complex during the early stages. A study was carried out to assess the sensitivity of some biochemical, hormonal and instrumental markers in the early diagnosis of osteitis fibrosa in patients undergoing hemodialysis due to chronic renal insufficiency. Of these markers, the assay of whole molecule PTH appeared to be the most sensitive and specific biological marker.

Adult↗
PubMed1992

[Comparison of acceptance tests of 5 linear electron accelerators for radiotherapy].

The acceptance tests of five electron linear accelerators have been analyzed to compare their completeness, the standards specified by the manufacturers and the measured deviations. Involved tests were relative to geometrical and mechanical parameters, photon and electron beam characteristics, dose monitoring systems, treatment table and safety systems. The comparison of acceptance tests has shown a significant nonuniformity, also due to the absence of a specific legislation; anyway, the measured deviations generally appeared to be within internationally recommended values.

Particle Accelerators↗
PubMed1991

Incidence of hip fractures in the elderly: a cross-national analysis.

This paper reviews international data on incidence rates of hip fracture in persons 50 years of age and older, based on a bibliographic search of articles published since 1960. Incidence rates are higher in white populations than in black, Asian, and Hispanic populations. In both sexes and in all ethnic groups and geographic areas, incidence rates increase markedly with age. The steep increase with age, however, occurs later in black, Asiatic and Hispanic populations than in whites. The ratio of female to male incidence rates is higher than 1.0 in whites, while in blacks and Asians it has often been the reverse, with higher rates among men. In recent years in Hong Kong incidence rates in females have increased more rapidly than incidence rates in males, so that now the incidence rates in females are higher than those in males. In addition to the study in Hong Kong, most studies in Northern Europe and North America show an increase in age-adjusted hip fracture incidence rates over time over the past few decades. Methodological differences among the various studies (including differences in the definition of hip fracture, in case ascertainment, and in the selection and sample size of the study population) necessitate cautious interpretation of the findings of this report.

Age Factors↗
PubMed1991

Aging.

Many issues are emerging as a consequence of the aging of modern populations. Developed as well as developing countries need to define the policies and programs that will reduce the burden of aging populations on societies and their economies, ensure the availability of health and social services for older persons, and promote their continuing participation in a socially and economically productive life. The situation is more challenging for developing countries, which must add new priorities to the scarce resources of their health and social programs when they still have to deal with the problems of their younger population. The World Health Organization is collaborating with the member states to find solutions that are adequate to their own situation. Promotion of research that will provide policymakers with data on the actual needs of their aging population is the main objective of the WHO international research program on aging.

Aged↗
PubMed1991

[The evaluation of urinary NAG activity in patients undergoing urography].

A study has been carried out to verify the nephrotoxic effect of hyperosmotic substances used as a contrast medium in radiology employing the enzymuria technique (NAG). The research was carried out in 202 patients, some of whom diabetic, suffering from various pathologies and subjected to perfusion urography by inoculating an iodate contrast medium (isopaque). The result showed that NAG urinary activity grows significant in the 24-36 hours subsequent to X-ray examination in both diabetics and nondiabetics although the increase is greater in the former. After 5-7 days, enzymuria returns to normal in nondiabetic patients but remains high in the diabetic.

Acetylglucosaminidase↗
PubMed1990

Diabetes mellitus and other cardiovascular risk factors in an elderly population.

The purpose of this study was to describe the prevalence of diabetes in a community-dwelling elderly population, and to assess whether other cardiovascular disease risk factors were more frequent in older diabetics than in non-diabetics. Results suggest that, with the exception of hypertension, other cardiovascular disease risk factors are not more prevalent in older diabetics and do not aggregate in older diabetics. However, there was a very high prevalence of hypertension among older diabetics. Of particular concern is the observation that 40% of diabetic individuals under treatment for hypertension still have unacceptably high blood-pressure levels. These results indicate a need for follow-up of high-blood-pressure treatment in older diabetic people.

Aged↗
PubMed1989

Blood pressure changes with aging: evidence for a cohort effect.

Data from cross-sectional surveys show an increase in systolic blood pressure with increasing age. However, cross-sectional data can be misleading. Our purpose in this study is to prospectively describe changes in systolic and diastolic blood pressure levels over time in community-dwelling elderly persons. The participants were 1,917 men and women aged 65 to 98 yr who had participated at least seven years in the Florida Geriatric Research Program, a community-based, multi-phasic health screening program located in Dunedin, Florida (USA). Our results show that contrary to the cross-sectional data, systolic and diastolic blood pressure levels tend to decrease with increasing age. Mean systolic blood pressure in women at the baseline visit (Visit 2) was 143 mmHg and three years later (Visit 5) it had dropped to 140 mmHg. This downward trend was consistent at all ages and for both men and women. Stratification by use of antihypertensive medication, weight change, and survivorship did not alter this association. Further follow-up of this cohort to Visit 7 revealed a U-shaped trend of blood pressure with aging. There was also clear evidence of a cohort effect, as the age-specific mean systolic blood pressure was consistently lower in each younger 5 yr birth cohort. Our results suggest that in a healthy elderly population, systolic and/or diastolic blood pressure levels do not increase with aging; this finding may have implications for the diagnosis and treatment of hypertension in the elderly.

Aged↗
PubMed1989

[Radiological study of the thorax. Evaluation of efficacy-efficiency of a large-field image intensifier in mass screening].

Chest X-ray is the most frequent examination in radiology and accounts for a considerable portion of total population radiation exposure, mostly in screening programs. The ideal radiographic system is the one providing the best image quality together with the lowest dose to the patient, at a low cost. In this paper the authors analyze the potentials of a new chest X-ray examination unit equipped with a large-screen image intensifier (TS 57-Siemens). Two-thousand subjects were examined with this unit. The technical aspects of everyday practice are analyzed from the radiologist's point of view, together with the dose to the patient, image quality, and costs.

Adult↗