Biomedical subjects

M Tebaldi

Publications and source records attributed to M Tebaldi.

6 recordsLinked to original sources

PubMed2003

Modulated speckle simulations based on the random-walk model.

The random-walk model is employed to simulate modulated speckle patterns. We demonstrate that the geometrical image approximation fails to describe the modulated speckle pattern. A new approach to analyzing this phenomenon is proposed. The validity of the approximations employed is verified by comparison of the simulation with the experimental results. Speckle metrological applications and phase measurement techniques could be improved by taking advantage of this model.

Journal Article↗

PubMed2000

Speckle photography with different pupils in a multiple-exposure scheme.

The use of different multiple-aperture pupils for recording each image in speckle photography is proposed. The introduction of suitable spatial frequency carriers, by internally modulating imaged speckles, allows one to selectively isolate or combine the spectral content of different images into spatially separated regions in the Fourier plane. Theoretical and experimental results extend the speckle photography technique to the depiction of several specklegrams of multiple uniform in-plane displacements. In this case, because different pupils are considered for recording, the cross-correlation functions for the amplitudes and intensities in the image plane are calculated on the basis of the statistical properties of the object. Also, the ensemble-average intensity in the Fourier plane is analytically derived, and fringe visibility is investigated.

Light↗

PubMed1998

Clinical economics review: functional (non-ulcer) dyspepsia.

Dyspepsia is common within the general population and it imposes a significant burden on health-care resources. Calculation of the economic implications of functional dyspepsia is constrained by the fact that it is only possible to make this diagnosis in a minority of individuals with the disorder, because many do not seek medical attention and investigation is not appropriate for all who do. Studies which attempt to assess the effectiveness or cost-effectiveness of therapy may be further constrained by the fact that there is now good evidence that many patients with dyspepsia seek medical attention not so much because of the severity of symptoms, but because they fear that the symptoms signal the presence of some serious underlying disease. In this situation, effective well-founded reassurance that no serious disease is present is an important outcome of medical intervention and one which should be included in an economic appraisal of dyspepsia management. For obvious reasons, it is sensible to compare the cost-effectiveness of various clinical management strategies applicable in dyspepsia. Decision-tree analyses are currently fashionable but suffer from the major defect that there is no theoretical basis from which patient satisfaction with treatment options can be assessed. It is suggested that for disorders such as functional dyspepsia, which are non-lethal and non-progressive, recommendations about acceptable clinical management strategies require that account be taken of patient satisfaction with the strategies being reviewed. Cost-effectiveness calculations which take no account of this aspect of outcome are of limited relevance to clinical practice.

Antacids↗

PubMed1998

Quality of life assessment in reflux disease.

The recognition of heartburn and acid regurgitation as manifestations of gastro-oesophageal reflux disease (GORD), and the suppression of these symptoms with therapy, represent an over-simplistic approach to the reflux patient. For GORD, as for other gastrointestinal disorders, it is evident that many patients suffer a greater impairment of well-being than has been appreciated hitherto, and that this impairment can be quantified using modern quality of life measuring techniques. Successful treatment normalizes quality of life in a manner which is substantially, but not wholly, predictable from symptom responses or the healing of oesophagitis. These observations raise the possibility that physicians' therapeutic intentions do not always match the patients' wishes. The appraisal of health status, or quality of life (QOL), is increasingly important in defining the implications of disease and for assessing the outcome of therapy. Hitherto, QOL evaluations have seemed relevant to circumstances of major physical disability and for patients receiving potentially unpleasant treatments, such as cancer chemotherapy, but it is now evident that QOL evaluation has much wider applicability, including relevance to common gastrointestinal disorders such as GORD.

Gastroesophageal Reflux↗

PubMed1996

Chronic obstructive pancreatitis in humans is a lithiasic disease.

In humans chronic obstructive pancreatitis (COP) is thought to be a disease devoid of ductal stones. The aim of this study was to verify the presence and frequency of calcifications in patients with COP and compare them with those found in patients with chronic calcifying/calcific pancreatitis (CCP). We conducted a retrospective ERCP investigation in 115 patients with documented chronic pancreatitis. Only 75 could be safely classified as COP or CCP. Fifty-three patients (M:F ratio, 5.6:1; mean age, 36.1 +/- 12.2 years) had CCP, 46 of whom (86.8%) with calcifications. Twenty-two patients (M:F ratio, 3.4:1; mean age, 45.3 +/- 16.2 years; p < 0.05 vs. CCP) presented COP at endoscopic retrograde cholangiopancreatography, 8 (36.4%) with ductal calcifications (p < 0.0001 vs. CCP). COP was secondary to acute pancreatitis in nine cases, to odditis in 11 cases, and to malignant tumor and hypertrophy of Oddi's sphincter, respectively, in the other two cases. The two patient groups showed no significant differences in drinking and smoking habits, number of painful relapses, disease duration, and incidence of diabetes, gallstones, and need for surgery. In conclusion, formation of ductal stones is by no means rare in COP and should be classified as a form of lithiasic pancreatitis. Early restoration of pancreatic outflow by removing the obstruction, or by shunt-type operations and abstinence from drinking and smoking, should resolve this type of disease.

Adult↗

PubMedDate not supplied

[Medical therapy of chronic idiopathic constipation].

The medical care of the idiopathic constipation requires the correct patient identification based on precise classification items and on physiopathological considerations. The laxative abuse is often the most difficult problem to be solved and it has to be dealt with the consideration of different clinical aspects (wrong diet, psychological profile, concomitant diseases, drug therapy, etc.). The first step exactly consists in the identification and correction of the wrong convictions, of the behavioural attitudes and of the unbalanced dietary habits. Adding bran is the second widely accepted therapeutic step based on both physiopathological and epidemiological considerations. Even if the mechanism of action is still not completely understood, the fibre addition per se leads to an improvement of the constipation in quite a relevant percentage of patients, although it is often poorly tolerated. Nevertheless there are peculiar conditions not responsive to the bran addition such as the so-called "anismus". For these situations different therapeutic approaches have been proposed with variable results. Among these we can mention the re-educational programmes of the modalities of the defecation using biofeedback techniques. The chronic idiopathic constipation not respondent to the conventional medical therapy appears anyway a problematic and very difficult condition both from the investigational viewpoint and the therapeutic options. Finally it can be stated that the laxatives have a certain role in those clinical conditions most probably leading to the constipation. For each therapeutic drug class it is, of course, of great importance to know its mode of action as well as its adverse event profile.

Cathartics↗