Wave amplitude gain within wedge waveguides through scattering by simple obstacles.

Wave confinement, e.g., in waveguides, gives rise to a huge number of distinct phenomena. Among them, amplitude gain is a recurrent and relevant effect in undulatory processes. Using a general purpose protocol to solve wave equations, the boundary wall method, we demonstrate that for relatively simple geometries, namely, a few leaky or opaque obstacles inside a θ wedge waveguide (described by the Helmholtz equation), one can obtain a considerable wave amplification in certain spatially localized regions of the system. The approach relies on an expression for the wedge waveguide exact Green's function in the case of θ=π/M (M=1,2,...), derived through the method of images allied to group theory concepts. The formula is particularly amenable to numerical calculations, greatly facilitating simulations. As an interesting by-product of the present framework, we are able to obtain the eigenstates of certain closed shapes (billiards) placed within the waveguide, as demonstrated for triangular structures. Finally, we briefly discuss possible concrete realizations for our setups in the context of matter and electromagnetic (for some particular modes and conditions) waves.

Metastasis to the male breast from carcinoma of the urinary bladder.

We report a case of male breast metastasis from a urothelial carcinoma. Only two cases of this type of metastasis have been previously reported, and these were in the female breast. Clinical examination showed a progressive swelling of the left mammary region, with periareolar skin infiltration. Both mammography and ultrasound showed a rounded mass. Only histological examination with immunohistochemical staining permitted the correct diagnosis to be made. A particular feature of the present case is the absence of contralateral gynaecomastia, normally seen in cases of metastatic tumour to the breast from prostatic carcinoma.

[Follow-up chest radiography in surgical breast cancer patients]. / La radiografia del torace nel controllo delle pazienti operate per neoplasia della mammella.

PURPOSE: We investigated to what extent the diagnostic findings of chest radiography can improve prognosis and treatment in surgical breast cancer patients. We also reviewed the literature and our personal findings to choose the optimal follow-up frequency to meet therapeutical and management needs, including radiation protection. MATERIAL AND METHODS: We retrospectively reviewed 1556 chest radiographs of 195 surgical patients with M0 breast cancer performed January 1990 to December 1996. Patient's history and clinical data were accurately reviewed to investigate the relation between protocol type and results. The maximalist or intensive protocol featured 3 chest radiographs a year, even in the absence of any specific signs; the results were reviewed in terms of early diagnosis and prolongation of life. RESULTS: Only 13% of the examinations had been performed following a specific clinical indication, while 87% had been performed for a generic referral. Recurrences were found in 0.6% only of the latter examinations, which means that radiography provided no diagnostic improvement or important change in treatment in as much as 99.4% of cases. In 1997 radiographic follow-up was made triannual instead of biannual as it used to be. DISCUSSION AND CONCLUSIONS: In the absence of specific clinical indications, chest radiography can be performed in the two projections once a year. More aggressive protocols requiring more frequent examinations are not justified, as the patient's life expectancy is not increased. Yearly examinations permit to meet economic and management needs, with a better use of time, staff and materials. Moreover, the clinical-diagnostic yield is not affected by the skipping of unselected examinations. Finally, another pro is the technical thoroughness of the examination with orthogonal projections and the possibility to use ionizing radiations, which improves the management of clinical risks. Maximum radiologist-oncologist cooperation in clinical practice can improve both diagnostic efficiency and treatment efficacy, by reducing the population dose and rationalizing the use of human, instrumental, structural and financial resources.

[Comparison of dietary intake of type I diabetic patients and nutritional recommendations]. / Confronto tra introito alimentare di diabetici tipo I con le raccomandazioni nutrizionali.

BACKGROUND: The management of type I diabetes mellitus requires a careful balance between nutrient intake, energy expenditure and dose and timing of insulin. According to the recommendations of the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD) the calories should be prescribed according to energy needs to achieve and maintain a desirable body weight. Many studies have shown that diets in which carbohydrates provide 50-60% of total energy are associated with improved blood glucose control and lower levels of LDL cholesterol. Whenever acceptable to the patients, natural foods containing unrefined carbohydrate should be substituted for the highly refined carbohydrates that are low in fiber. The high risk of macrovascular disease in patients with diabetes dictates a need to restrict total fat (25-30% of total energy) and cholesterol intake (300 mg/day). ADA and EASD suggest that reduction of protein intake (0.8 g/kg/day) may reduce proteinuria and progression to renal failure during the earliest stages of diabetic nephropathy. METHODS: The goal of this study was to describe macronutrient intakes in type I diabetic patients of our Centre by a validated 3 day record. RESULTS: Mean energy intake was 2022+/-427 Kcal/die (vs 2596+/-501 recommended intake). Average protein intake was well above the level of 0.8 g/kg/day required to ensure an adequate protein intake in type I diabetes mellitus. Total fats contributed 29.8+/-7.4 of total energy (vs 27% recommended intake) and saturated fat provided significantly more than 10% of energy. Carbohydrates intake was above 50% of total energy but fiber intakes was substantially lower than the recommendation (12.7+/-5.5 vs 20.1+/-6.6 g/day). CONCLUSIONS: These data indicate current problems in the nutritional intake of type I diabetes mellitus; in fact the majority of our group of patients are not meeting the recommended dietary intakes for protein, total fat, saturated fat and fiber.

[Effect of treatment with biosynthetic GH on thyroid function in patients with an isolated deficiency of GH]. / Effetti del trattamento con GH-biosintetico sulla funzione tiroidea in soggetti con deficit isolato di GH.

The use of GH treatment in subjects with a GH deficiency has led to contrasting results concerning its impact to develop thyroid hyperfunction, whereas many others have underlined the possible onset of hypothyroidism. A number of studies have been carried out over short periods in subjects with multiple tropin deficiencies, in healthy adults or adults with GH deficiencies, in healthy adults or adults with GH deficiencies. The aim of the present study was to assess the effect of prolonged treatment with biosynthetic GH on thyroid function in children with an isolated idiopathic GH deficiency. The study included 8 children (mean age 10.4 +/- 0.8 years) with GH deficiencies treated with biosynthetic GH and 8 children with familial retarded stature of a similar age (mean age 10.3 +/- 0.7 years) who represented the control group. Serum levels of T3, T4, FT3, FT4 and TSH were measured at the start of the study and after one year of continuous GH treatment in subjects with GH deficiency; the same tests were performed in the control group on recruitment and after one year's observation without therapy. T4 and FT4 levels diminished, but not significantly, whereas there was a significant increase in plasma levels of T3 and FT3 (p less than 0.01); TSH values were significantly reduced in the treated group (p = 0.025). No significant variations in thyroid parameters were found in the control group. These data support the hypothesis of an increased peripheral conversion of T4 into T3 due to GH therapy; in conclusion, however, no significant variation in thyroid function was observed following GH replacement therapy, even if prolonged, in subjects with an idiopathic isolated GH deficiency.

[The primary empty sella syndrome: a clinical and neuroradiological study of 10 cases]. / La sindrome della sella vuota primitiva: studio clinico e neuroradiologico di 10 casi.

Primary empty sella is an anatomical entity in which an enlarged pituitary fossa is partially filled with cerebrospinal fluid owing to the arachnoid herniation and the pituitary gland is compressed against the fossa. This condition can be due to an inherent weakness of the diaphragma of the sella as well as to an increase in intracranial pressure. Empty sella can be associated with neuroradiological and endocrine symptoms and the present study reports the clinical, endocrine and radiological features in 10 patients with primary empty sella syndrome. We conclude that the endocrine alterations are frequent in the empty sella syndrome and that the most specific and sensible neuroradiological investigation is N.M.R.

[Paravertebral block of the lumbar plexus. Variations of the original technic]. / Blocco del plesso lombare per via paravertebrale. Variante alla metodica originale.

After studying a hundred or so abdominal CT scans carried out at L5 level and having verified that the interfascial compartment between the quadrate muscle of the lumbi and the psoas muscle is relatively fixed (1.8-2.3 cm), it is proposed to utilise this datum (introduction of the 2 cm) needle after contact with the transverse apophysis of L5) to identify the psoas compartment which contains most of the nerves making up the lumbar plexus. Study of the series and results obtained confirm the value and simplicity of the proposed technique.

[Incidence and severity of postoperative anemia in elderly patients treated with Ender intramedullary nails]. / Incidenza e gravità dell'anemia postoperatoria nel paziente geriatrico trattato con chiodi endomidollari di Ender.

Stress is laid on the state of progressive anaemia that follows osteosynthesis with Ender intramedullary nails in elderly patients suffering from femoral pertrochanteric fracture. The behaviour of haemochromocytometric values has been examined in a series of 56 female patients aged more than 75, from the time of admission to the fourth day subsequent to surgery: in sharp contrast with the minor trauma triggered by the operation, a significant reduction was observed in haemoglobinaemia and in haematocrit value. Attempting, hypothetically, to give a plausible justification to these results, it is concluded by recommending careful clinical and laboratory control during the days immediately following the operation.