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Biomedical subjects

S Rinaldi

Publications and source records attributed to S Rinaldi.

At least 55 records · Page 3Linked to original sources
PubMed2000

Serum C-peptide, insulin-like growth factor (IGF)-I, IGF-binding proteins, and colorectal cancer risk in women.

BACKGROUND: Leading a Western lifestyle, being overweight, and being sedentary are associated with an increased risk of colorectal cancer. Recent theories propose that the effects of these risk factors may be mediated by increases in circulating insulin levels and in the bioactivity of insulin-like growth factor (IGF)-I. To test this hypothesis, we conducted a case-control study nested within a cohort of 14 275 women in New York. METHODS: We used blood samples that had been obtained from these women from March 1985 through June 1991 and stored in a biorepository. C-peptide (a marker for insulin secretion), IGF-I, and IGF-binding proteins (IGFBPs)-1, -2, and -3 were assayed in the serum of 102 women who subsequently developed colorectal cancer and 200 matched control subjects. Logistic regression was used to relate cancer risk to these peptide levels, by adjustment for other risk factors. All statistical tests used are two-sided. RESULTS: Colorectal cancer risk increased with increasing levels of C-peptide (P:(trend) =.001), up to an odds ratio (OR) of 2. 92 (95% confidence interval [CI] = 1.26-6.75) for the highest versus the lowest quintiles, after adjustment for smoking. For colon cancer alone (75 case subjects and 146 control subjects), ORs increased up to 3.96 (95% CI = 1.49-10.50; P:(trend) <.001) for the highest versus the lowest quintiles. A statistically significant decrease in colorectal cancer risk was observed for increasing levels of IGFBP-1 (P:(trend) =.02; OR in the upper quintile = 0.48 [95% CI = 0.23-1. 00]), as well as for the highest quintile of IGFBP-2 levels (P:(trend) =.06; OR = 0.38 [95% CI = 0.15-0.94]). Colorectal cancer risk showed a modest but statistically nonsignificant positive association with levels of IGF-I and was statistically significantly increased for the highest quintile of IGFBP-3 (OR = 2.46 [95% CI = 1. 09-5.57]). CONCLUSIONS: Chronically high levels of circulating insulin and IGFs associated with a Western lifestyle may increase colorectal cancer risk, possibly by decreasing IGFBP-1 and increasing the bioactivity of IGF-I.

Adult↗
PubMed2000

Fatal disseminated Nocardia farcinica infection in a renal transplant recipient.

Six years after a renal cadaver transplant, a 20-year-old girl developed multiple painful cutaneous abscesses and bilateral pneumonia secondary to Nocardia farcinica infection. Despite broad in vitro sensitivity to several antibiotic agents and aggressive medical treatment, the patient failed to respond and died after 10 weeks of therapy. We conclude that Nocardia farcinica is a very aggressive organism in immunocompromised patients and is often resistant to antimicrobial agents.

Adult↗
PubMed2000

Paecilomyces variotii peritonitis in an infant on automated peritoneal dialysis.

Fungal peritonitis is a serious complication of chronic peritoneal dialysis (CPD) and is frequently associated with CPD drop-out. Paecilomyces variotii, a common saprophytic fungus, rarely causes human infection. To date, only nine adult or adolescent patients with P. variotii peritonitis during continuous ambulatory peritoneal dialysis have been reported. In all patients, successful treatment required antifungal therapy and removal of the peritoneal catheter. We report the first case of P. variotii peritonitis in an infant on automated peritoneal dialysis successfully treated with combined intraperitoneal and oral fluconazole, without removal of the peritoneal catheter.

Administration, Oral↗
PubMed2000

High endogenous estradiol is associated with increased venous distensibility and clinical evidence of varicose veins in menopausal women.

OBJECTIVE: The purpose of this study was to determine if there is an association between elevated sex hormones (ie, serum estradiol, sex hormone binding globulin [SHBG], testosterone) and increased venous distension and clinical evidence of varicose veins in menopausal women. METHODS: Participants were 104 healthy volunteer menopausal women, aged 48 to 65 years, who were not undergoing hormonal treatment. Of these 104, 14 were excluded from analyses because their estradiol levels were compatible with a premenopausal condition (4), because they had missing values for insulin concentration (5), and because they did not show up at venous vessel examination (5). Patients underwent a physical examination to determine the presence of varicose veins; a venous strain-gauge plethysmographic examination to compute instrumental measures of venous distensibility; and laboratory analyses of blood so serum testosterone, estradiol, SHBG, glucose, and insulin could be measured. There were also prevalence ratios and odds ratios used to test the presence of an association between biochemical and instrumental variables. RESULTS: Serum levels of estradiol in the upper tertile of the frequency distribution were significantly associated with clinical evidence of varicose veins (prevalence odds ratios 3.6; 95% CI 1.1-11.6) and with increased lower limb venous distensibility (prevalence odds ratios 4.4; 95% CI 1.2-15.5). No association was found for SHBG and testosterone. CONCLUSIONS: Our finding that high serum levels of estradiol are associated with clinical evidence of varicose veins and instrumental measurements indicating increased venous distensibility in menopausal women suggests that endogenous estrogens may play a role in the development of this very common venous vessel abnormalities.

Aged↗
PubMed2000

Retroperitoneal laparoscopy for renal biopsy in children.

PURPOSE: We report our experience with the retroperitoneal laparoscopic approach for treating pediatric patients and when the percutaneous needle approach is not possible due to uncontrolled hypertension, bleeding disorders, anti-clotting medications and anatomical abnormalities. MATERIALS AND METHODS: Retroperitoneal laparoscopic renal biopsy was performed in 20 patients 2 to 18 years old (mean age 9.7) during a 16-month period. At the same time 53 percutaneous needle biopsies and 1 open biopsy were performed. The child is in a flank position, and 2 trocars are used via a direct vision approach. The first trocar is 12 mm. in diameter and positioned on the posterior axillary line, and the second trocar is 5 mm. in diameter and is entered 4 cm. anteriorly. Gentle dissection is done to free the lower pole of the selected kidney, biopsy forceps are used to grasp the specimen under direct vision and the biopsy site is fulgurated using bipolar electrocautery. RESULTS: Biopsy was performed successfully in all cases except 1, which was converted to an open procedure. Mean operative time was 40 minutes, blood loss was minimal and mean hospital stay was 1.2 days postoperatively. No pain medication was required postoperatively, and all patients returned to their usual activities within 3 to 5 days. A minor intraoperative complication, which was a peritoneal tear with no postoperative sequelae, occurred in 1 case. CONCLUSIONS: The retroperitoneal laparoscopic technique is simple and safe, and does not require extensive laparoscopic experience. We believe that this approach is reliable, and has less morbidity and several advantages compared to open surgery. It should be selected as the first choice for treating pediatric patients when percutaneous needle renal biopsy is contraindicated.

Adolescent↗
PubMed1999

Virtual reality based experiential cognitive treatment of anorexia nervosa.

The treatment of a 22-year old female university student diagnosed with Anorexia Nervosa is described. In the study the Experiential Cognitive Therapy (ECT) was used: a relatively short-term, integrated, patient oriented approach that focuses on individual discovery. Main characteristic of this approach is the use of Virtual Reality, a new technology that allows the user to be immersed in a computer-generated virtual world. At the end of the in-patient treatment, the subject increased her bodily awareness joined to a reduction in her level of body dissatisfaction. Moreover, the patient presented a high degree of motivation to change. The results are discussed with regard to Vitousek, Watson and Wilson (1998, Clinical Psychology Review, 18(4), 391-420) proposal of using the Socratic Method to face denial and resistance of anorectic patients.

Adult↗
PubMed1999

Purpura of the ears: a distinctive vasculopathy with circulating autoantibodies complicating long-term treatment with levamisole in children.

The cutaneous side-effects of levamisole include non-specific and lichenoid eruptions, fixed drug eruption and, very rarely, cutaneous vasculitis. We describe a distinctive clinical and histological vasculopathy with immunological abnormalities in children with paediatric nephrotic syndrome receiving long-term levamisole treatment. Four boys and one girl were identified. Their average age was 10 years. Levamisole had been used for an average of 24 months. Purpura of the ears was the most common finding corresponding histologically to a vasculopathic reaction pattern ranging from a leucocytoclastic and thrombotic vasculitis to a vascular occlusive disease without true vasculitis but with associated antinuclear, antiphospholipid and anticytoplasmic antibodies. The eruption resolved in all patients 2-3 weeks after the discontinuation of levamisole, but serum autoantibodies persisted for 2-14 months.

Adjuvants, Immunologic↗
PubMed1999

The use of PC based VR in clinical medicine: the VREPAR projects.

Virtual reality (VR) is an emerging technology that alters the way individuals interact with computers: a 3D computer-generated environment in which a person can move about and interact as if he actually was inside it. Given to the high computational power required to create virtual environments, these are usually developed on expensive high-end workstations. However, the significant advances in PC hardware that have been made over the last three years, are making PC-based VR a possible solution for clinical assessment and therapy. VREPAR - Virtual Reality Environments for Psychoneurophysiological Assessment and Rehabilitation - are two European Community funded projects (Telematics for health - HC 1053/HC 1055 - http://www.psicologia.net) that are trying to develop a modular PC-based virtual reality system for the medical market. The paper describes the rationale of the developed modules and the preliminary results obtained.

Cerebrovascular Disorders↗
PubMed1998

Acidic deposition, plant pests, and the fate of forest ecosystems.

We present and analyze a nonlinear dynamical system modelling forest-pests interactions and the way they are affected by acidic deposition. The model includes mechanisms of carbon and nitrogen exchange between soil and vegetation, biomass decomposition and microbial mineralization, and defoliation by pest grazers, which are partially controlled by avian or mammalian predators. Acidic deposition is assumed to directly damage vegetation, to decrease soil pH, which in turn damages roots and inhibits microbial activity, and to predispose trees to increased pest attack. All the model parameters are set to realistic values except the inflow of protons to soil and the predation mortality inflicted to the pest which are allowed to vary inside reasonable ranges. A numerical bifurcation analysis with respect to these two parameters is carried out. Five functioning modes are uncovered: (i) pest-free equilibrium; (ii) pest persisting at endemic equilibrium; (iii) forest-pest permanent oscillations; (iv) bistable behavior with the system converging either to pest-free equilibrium or endemic pest presence in accordance with initial conditions; (v) bistable behavior with convergence to endemic pest presence or permanent oscillations depending on initial conditions. Catastrophic bifurcations between the different behavior modes are possible, provided the abundance of predators is not too small. Numerical simulation shows that increasing acidic load can lead the forest to collapse in a short time period without important warning signals.

Acid Rain↗
PubMed1998

Chaos and peak-to-peak dynamics in a plankton-fish model.

A plankton-fish model, comprising phosphorus, algae, zooplankton, and young fish, with light intensity and water temperature varying periodically with the seasons, is analyzed in this paper. For realistic values of the parameters the model behaves chaotically, but its dynamics within the strange attractor can be described by a few one-dimensional maps that allow one to forecast the next yearly peak of plankton or fish from the last peaks. This property is an unambiguous mark of a special form of chaos. Unfortunately, the estimate of such peak-to-peak maps from field data is possible only if plankton or young fish biomass has been sampled accurately and frequently for a paramount number of years. In conclusion, the analysis shows that it might be that plankton dynamics are characterized by an interesting and peculiar form of chaos, but that inferences from recorded data on the existence of these forms of chaos are premature.

Animals↗
PubMed1998

Experiential cognitive therapy in anorexia nervosa.

The paper details the characteristics of Experiential Cognitive Therapy (ECT), a relatively short-term, integrated, patient-oriented approach that focuses on individual discovery. Its novelty is the use of Virtual Reality, a new technology that could play an important role in clinical psychology, since it enables ECT to address both body experience disturbances and motivation for change, two key topics in the treatment of anorexia nervosa. All the phases of ECT are described with reference to an actual clinical case: a 22-year-old female anorectic patient.

Adult↗
PubMed1998

Singular homoclinic bifurcations in tritrophic food chains.

The Rosenzweig-MacArthur food chain model is proved to have homoclinic orbits. The proof is in two steps. First, we use a geometric approach based on singular perturbation and detect singular homoclinic orbits as well as parameter combinations for which these orbits exist. Second, we show, numerically, that for slightly different parameter values there exist also nonsingular homoclinic orbits that tend toward the singular ones when the time responses of the three trophic levels are extremely diversified. The analysis is performed without exploiting too deeply the mathematical structure of the Rosenzweig-MacArthur model. This is done intentionally, to assist readers interested more in the methodology than in the application to food chains.

Animals↗
PubMed1998

Experiential cognitive therapy: a VR based approach for the assessment and treatment of eating disorders.

Even if there has been significant progress in research on eating disorders, little empirical work has been done yet to specify the content of clinical guidelines and to validate their efficacy in treatment. In particular there are at least three themes that are somehow neglected by current guidelines: body experience disturbances, motivation for change and the integration between the different approaches used. This chapter details the characteristics of the Experiential Cognitive Therapy (ECT), an integrated approach ranging from cognitive-behavioral therapy to virtual reality (VR) sessions. In particular, using VR, ECT is able to address both body experience disturbances and motivation for change. In the chapter a description of all the phases of this approach are offered by using an actual clinical case: a 22-year old female anorectic patient.

Adult↗
PubMed1998

Detoxification process for glutaraldehyde-treated bovine pericardium: biological, chemical and mechanical characterization.

BACKGROUND AND AIMS OF THE STUDY: Glutaraldehyde cross-linked bovine pericardium was post-treated with homocysteic acid in order to bond unreacted glutaraldehyde groups, and preserved in aldehyde-free solution to reduce the toxicity and calcification potential of the tanned tissue. The study aim was to verify the efficacy and preservation of chemical and mechanical properties of pericardial tissue treated in this way. METHODS: Detoxification efficacy was tested by measuring free aldehyde groups and by in vitro cultivation of human endothelial cells on pericardial samples. Material stability tests included mechanical characterization, shrink temperature measurement, pronase digestion resistance and amino acid analysis after acid hydrolysis. The effect of treatment on fatigue resistance was evaluated by monitoring changes in permeability and compliance caused by 15 x 10(6) cycles of pulsatile stress. RESULTS: Detoxified samples showed negligible glutaraldehyde residues and significantly improved endothelial cell proliferation compared with conventionally treated samples. Chemical and mechanical properties were similar in detoxified and glutaraldehyde-treated samples. Tissue fatigue behavior was not modified by homocysteic acid treatment. CONCLUSION: Homocysteic acid treatment effectively reduces toxicity but does not affect the stability of glutaraldehyde cross-linked pericardium.

Adult↗
PubMed1998

Detoxified glutaraldehyde cross-linked pericardium: tissue preservation and mineralization mitigation in a subcutaneous rat model.

BACKGROUND AND AIM OF THE STUDY: Glutaraldehyde is considered a promoter of calcification by the action of toxic aldehyde group residuals from cross-linking. Post-fixation treatment with homocysteic acid (HA), besides bonding aldehyde groups and neutralizing toxicity, should enhance biocompatibility due to the strongly electronegative sulfonic group. The aim of this investigation was to evaluate HA efficacy on tissue preservation and dystrophic calcification mitigation in glutaraldehyde cross-linked bovine pericardium (BP) using a subcutaneous rat model. METHODS: Four samples of BP, two with glutaraldehyde-HA and two with glutaraldehyde treatment, were implanted in each of 24 male Sprague-Dawley rats. Three rats were killed at 14 days, eight at 28 days, eight at 56 days and five at 84 days. Unimplanted glutaraldehyde-HA- and glutaraldehyde-treated samples served as controls. All samples were studied by gross examination, mammography, light transmission and scanning electron microscopy, and atomic absorption spectroscopy. The nature of mineralization was investigated by coupling techniques of scanning electron microscopy, electron microprobe analysis and X-ray powder diffraction. RESULTS: No histological and ultrastructural differences were found between glutaraldehyde-HA- and glutaraldehyde-treated BP, whether implanted or unimplanted. In both groups, calcification progressed with time, but significantly less after glutaraldehyde-HA treatment than after glutaraldehyde alone and at all time intervals (14.63 +/- 21.34 versus 43.17 +/- 15.99 at 28 days, p = 0.003; 56.42 +/- 40.20 versus 90.59 +/- 32.90 at 56 days, p = 0.008; 91.68 +/- 67.68 versus 156.23 +/- 17.85 at 84 days, p = 0.01). Differences were evident by mammography and histology (von Kossa stain). Electron microprobe analysis in both groups showed the composition of calcified nuclei to be calcium phosphate, stoichiometrically close to apatite (Ca5(PO4)3(OH)). The occurrence of crystallized apatite was supported by X-ray powder diffraction findings, the amount of crystallized apatite being higher in glutaraldehyde-treated samples. CONCLUSIONS: Post-fixation treatment with HA preserves BP structural properties and significantly mitigates mineralization of long-term subcutaneous implants.

Animals↗