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Biomedical subjects

A D'Ambrosio

Publications and source records attributed to A D'Ambrosio.

At least 19 recordsLinked to original sources
PubMed2006

Structure-function relationships in the human visual system using DTI, fMRI and visual field testing: pre- and post-operative assessments in patients with anterior visual pathway compression.

The focus of this project is to improve our understanding of the relationships between brain structure and function in patients presenting with anterior visual pathway compression using functional MRI (fMRI), visual field(VF) maps and diffusion tensor imaging (DTI). Significant visual loss can occur when large pituitary lesions compress the optic chiasm. Surgical resection of these lesions decompresses the chiasm and can lead to visual recovery. In this preliminary study, we selected patients presenting with slowly progressive visual loss secondary to a compressive pituitary region mass. Using preoperative DTI data, we reconstructed white matter projections of the optic radiations and demonstrated a structural correlation with functional vision as quantified by formal visual field mapping and fMRI. The structural data generated through a fiber tracking algorithm may represent a potentially powerful tool to better understand functional visual deficits in patients with anterior visual pathway compression. Furthermore, we believe that specific patterns in preoperative DTI data may predict the likelihood of postoperative visual recovery in a select group of patients.

Brain↗
PubMed2005

Proteolysis in miniature cheddar-type cheeses manufactured using extracts from the crustacean Munida as coagulant.

Miniature (20 g) Cheddar-type cheeses were manufactured using enzymes extracted from the crustacean Munida or chymosin as coagulant. Cheeses were ripened at 8 degrees C and samples were collected for analysis after 2, 6 and 12 weeks. Proteolysis was assessed by urea-polyacrylamide gel electrophoresis, which showed that cheeses manufactured with the Munida extracts had a higher extent of degradation of beta-casein than cheeses made using chymosin as coagulant. Patterns of proteolysis were also obtained by reverse-phase high-performance liquid chromatography (RP-HPLC) and matrix assisted laser desorption ionisation-time of flight (MALDI-ToF) mass spectrometry. In general, the products of proteolysis were more complex in cheese made using the Munida extracts than in cheese made by chymosin as coagulant. Statistical analysis of results clearly discriminated the cheeses on the basis of coagulant used. Molecular mass of peptides found in cheese made using Munida extracts were similar to those of peptides commonly detected in cheeses made using chymosin as coagulant.

Animals↗
PubMed2003

Extracting and purifying R-phycoerythrin from Mediterranean red algae Corallina elongata Ellis & Solander.

R-Phycoerythrin (R-PE) is a protein acting as a photosynthetic accessory pigment in red algae (Rodophyta). This protein has gained importance in many biotechnological applications in food science, immunodiagnostic, therapy, cosmetics, protein and cell labelling, and analytical processes. In this paper we report on a new, one step procedure for the extraction and purification of R-PE from a new source: the Mediterranean red algae Corallina elongata Ellis & Solander. This red algae contains mainly R-PE and is suitable for the production in culture. No other contaminating phycobiliproteins could be detected in the extracts. The method we propose for the purification is based on the use of hydroxyapatite, a chromatographic resin that can be produced in the laboratory at very low cost and can be used batch-wise with large amounts of extracts, alternative to chromatography, and therefore can be scaled up. Both the yield and the purity of R-PE are very good.

Adsorption↗
PubMed2003

Intermittent warm blood cardioplegia induces the expression of heat shock protein-72 by ischemic myocardial preconditioning.

OBJECTIVE: Recent studies have demonstrated that the induction of heat shock protein-72 (HSP72) by different stimuli preserves the heart function after cardioplegic arrest. Based on these findings, we investigated whether intermittent warm blood cardioplegia would induce changes in the myocardial expression of HSP72. METHODS: Forty patients scheduled for aortocoronary bypass were randomly assigned to receive either cold or warm intermittent blood cardioplegia. In all patients HSP72 and HSP72 mRNA were assayed in biopsies from the right atrium at baseline, and during the reperfusion period. Plasma CK-MB and troponin-T, and myocardial oxygen extraction and lactate release were also measured. RESULTS: In both groups, myocardial expression of HSP72 increased throughout the reperfusion period, but the values of HSP72 band lengths were significantly higher in the warm group. Correspondingly, HSP72 mRNA levels increased progressively in both groups, with significant difference between groups observed in biopsies at the reperfusion. Warm blood cardioplegia was associated with lower levels of CK-MB and troponin-T. Myocardial oxygen extraction and lactate release were higher during intermittent warm cardioplegia, indicating a more profound ischemic anaerobic metabolism in the warm group. CONCLUSIONS: Intermittent warm blood cardioplegia induces an increased expression of HSP72 and it is associated with a better myocardial protection, by a mechanism involving a variant of the classical ischemic preconditioning model.

Coronary Artery Bypass↗
PubMed2003

Electron paramagnetic resonance and ultraviolet/visible study of compounds I and II in the horseradish peroxidase-H(2)O(2)-silk fiber reaction system.

The enzymatic oxidation of silk with H(2)O(2) in the presence of horseradish peroxidase (HRP) has been investigated. Two intermediate complexes have been observed during this reaction. Both can be attributed to Fe(4+) ions axially bonded to an oxygen atom and to a porphyrin radical (P). In the most unstable of them, indicated as compound II, the chemical bond between [Fe(IV)=O](2+) and P was weaker than in the other, indicated as compound I. The former compound disappeared within 1 h of the reaction, at difference with the latter, traces of which were observed even after 3 weeks with dried samples. However, the chemical bond between [Fe(IV)=O](2+) and P in compound I weakened during the sample ageing. All these phenomena have been enlightened by electron paramagnetic resonance (EPR) and spectrophotometric ultraviolet/visible (UV/Vis) measurements.

Electron Spin Resonance Spectroscopy↗
PubMed2003

Simvastatin attenuates leucocyte-endothelial interactions after coronary revascularisation with cardiopulmonary bypass.

OBJECTIVE: To investigate the effects of preoperative simvastatin treatment on leucocyte-endothelial interactions following coronary artery bypass surgery with cardiopulmonary bypass. DESIGN: Double blind crossover study. Experiments on polymorphonuclear cells (neutrophils) were done at the end of cardiopulmonary bypass and one hour postoperatively. Endothelial P-selectin expression and neutrophil/endothelial adhesion were evaluated under either normoxic or hypoxic conditions. SETTING: University hospital (tertiary referral centre). PATIENTS: Three groups of patients undergoing coronary bypass surgery: 20 patients taking simvastatin for cholesterol control, 16 patients not responsive to simvastatin, and 20 controls. MAIN OUTCOME MEASURES: Expression of neutrophil CD11b and endothelial P-selectin; adhesion of neutrophils to endothelium. RESULTS: Cardiopulmonary bypass resulted in a significant increase in neutrophil CD11b expression in all groups. Similarly, the exposure of saphenous vein to hypoxia/reoxygenation induced an augmentation of endothelial P-selectin. However, both neutrophil CD11b expression and endothelial P-selectin exocytosis were less in the simvastatin groups than in the controls. Cardiopulmonary bypass and controlled hypoxia/reoxygenation stimulated neutrophil/endothelial adhesion, but the number of adhering cells was less in the simvastatin groups than in the controls, irrespective of the cholesterol concentration. Treatment of endothelial cells with L-NAME completely reversed the effects of simvastatin. CONCLUSIONS: Pretreatment with simvastatin reduces neutrophil adhesion to the venous endothelium in patients undergoing coronary surgery, irrespective of its efficacy at lowering cholesterol concentration.

Anticholesteremic Agents↗
PubMed2002

Central precocious puberty in multisystem Langerhans cell histiocytosis: a case report.

The authors describe a girl with multisystem Langerhans cell histiocytosis (LCH) who developed central precocious puberty (CPP). At the age of 19 months she presented with otorrhea and polypoid formations in the ear canal; polyps were removed and LCH suspected. She subsequently developed diabetes insipidus with a documented lesion of the pituitary stalk; she received chemotherapy and began therapy with l-desamino-8-D-argininevasopressin. Growth hormone deficiency was diagnosed at the age of 4.4 years and GH replacement therapy started. The patient has been off therapy for LCH since the age of 6. Signs of pubertal development appeared at 7.5 years (bone age 8 years) and gonadotropin-releasing hormone analog (GnRHa) treatment was started. During the observation period she developed central hypothyroidism. Development of CPP during LCH is extremely rare; to the authors 'knowledge, no patient has been described so far. The authors believe that CPP was secondary to LCH and did not represent a casual finding, even in the absence of hypothalamic-pituitary axis involvement. The presence of preceding lesions producing excessive cytokine levels, with damage on the neurosecretory apparatus that inhibits the GnRH pulse generator, represents the most intriguing hypothesis. The possibility of CPP development should be considered during the follow-up of these patients.

Child↗
PubMed2001

Corpus callosum agenesis, multiple cysts, skin defects, and subtle ocular abnormalities with a de novo mutation [45,XX,der(5), t(5;;14) (pter;q11.2)].

We report on a 2-year-old girl with a de novo mutation [45,XX,der(5),t(5;14) (pter;q11.2)] with corpus callosum agenesis, multiple cysts (cerebral and cardiac), subtle eye abnormalities, and at least two different skin defects, strongly indicating neuroectodermal involvement, as a neuromuscular choristoma (hamartoma) and an eccrine hamartoma. Fluorescent in situ hybridization with different single-locus probes showed that chromosome 5 has a very small deletion, confined to a region composed of repetitive sequences. By contrast, the long (q) arm of chromosome 14 seems to be much more involved in the rearrangement, with partial monosomy spanning from the centromere to the D14S72 and D14S261 loci. The extent of the deleted region of chromosome 14 is approximately 16 cM. To our knowledge, this is the smallest reported deletion involving the chromosome 14q11.2 region to be associated with a developmental disorder resulting in variable eye, skin, and brain anomalies. We suggest that a new syndrome, mimicking in some ways the MLS phenotype, is caused by a deletion in the chromosome 14q11.2 region.

Abnormalities, Multiple↗
PubMed2001

[S(-) bupivacaine (levobupivacaine) in peripheral blocks: preliminary results].

We have compared the onset time, anesthetic potency and adverse effects of three local anaesthetics (ropivacaine, levobupivacaine and bupivacaine) in two type of peripheral blocks (brachial plexus block for upper limb and femoral nerve block for lower limb) in adult patients in a double blind, randomized, prospective study. A total of 66 patients undergoing orthopaedic surgery were randomly allocated to receive brachial plexus block or femoral nerve blockade with 0,5% ropivacaine (group R, n=22), 0,5% levobupivacaine (group L, n=22) or 0,5% bupivacaine (group B, n=22), each groups has been divided into two subgroups (LBP n=11, RBP n=11, BPB n=11, LBF n=11, RBF n=11, BBF n=11) dipending on the type of block. The onset of sensory nerve block was similar for the three groups; the onset of motor block and onset time ready to surgery were faster in group R (-30%) if compared with group L and B. The duration of motor block and sensory block was respectively longer in group L and in group B. Study results have not been influenced by the blocks, except for plexus nerve block where we observed the same results for group B and group R in relation to onset time ready to surgery. VRS scores were higher in group R as showed by the number of analgesic request in postoperative period. We did not observe any adverse effect. We conclude that ropivacaine acts faster with less interpatient variability, while levobupivacaine and bupivacaine offer a prolonged postoperative analgesia. For this reason, with the exception of bupivacaine due to major cardio and neuro toxicity, we can indifferently use levobupivacaine or ropivacaine depending on the requested characteristics of the anesthetic.

Amides↗
PubMed2000

Early and long-term results of stenting of diffuse coronary artery disease.

Diffuse coronary artery disease (CAD) is considered unfavorable for interventional procedures; however, the results of stenting of diffuse CAD have not been completely characterized. We performed stenting in 100 consecutive patients with diffuse CAD, defined as significant stenosis >20 mm (n = 59 patients), multiple significant stenoses in the same artery (n = 23 patients), or significant narrowing involving the whole length of the coronary artery (n = 18 patients). Angiographic success was achieved in 103 arteries (100%) and clinical success was obtained in all 100 patients. There were no deaths; no patient had stent closure, acute myocardial infarction, or required emergency coronary artery bypass surgery. All 100 patients had >6 months follow-up (mean 18 +/- 7 months, range 7 to 31); 77 (77%) remained asymptomatic, and 5 (5%) had acute myocardial infarction, of whom 2 died (2%). In-stent restenosis was observed in 12 patients (12%) and repeat angioplasty was performed in 10. Including those patients who underwent repeat angioplasty, 89 (89%) maintained clinical improvement and 95 (95%) were alive and free of bypass surgery during follow-up. Life-table analysis showed 86% freedom from death, myocardial infarction, and target lesion revascularization at 28 months. Thus, selected patients with diffuse CAD may be treated with satisfactory acute and long-term results by stent implantation.

Angioplasty, Balloon, Coronary↗
PubMed2000

Vagal and hypoglossal Bell's palsy.

A 7-year-old boy was referred because of a sudden change to nasal speech, dysarthria for words with explosive consonants in speech, and nasal regurgitation of fluids. The symptoms arose over 1 week following a capricious episode of acute asthmatic bronchitis. Physical and neurologic examinations were normal except for a left deviation of the uvula, accompanied by a "curtain" movement of the posterior pharyngeal wall against the opposite side, and a left deviation of the protruded tongue. No vascular, traumatic, infectious, neoplastic, or neurologic causes could be identified. No therapy was administered. Full recovery occurred 4 months later. The diagnosis was idiopathic vagal and right hypoglossal nerve palsy (Bell's palsy).

Bell Palsy↗
PubMed1999

Reducing perioperative blood loss in patients undergoing total hip arthroplasty.

In this prospective, randomised, double-blind study, we investigated the effect of epidural anaesthesia and an antifibrinolytic agent, Aprotinin (500,000 KIU in bolus before surgery and 500,000 KIU h(-1) in drip form during surgery), on intra and postoperative blood loss and transfusion requirements in total hip arthroplasty. Sixty patients were allocated randomly to four groups (A: epidural + general anesthesia + Aprotinin, B: epidural + general anesthesia + placebo (equal volume), C: general anaesthesia + Aprotinin, D: general anaesthesia + placebo). Postoperative analgesia: epidural analgesia in groups A and B, systemic analgesia with opiates in groups C and D. Blood loss during surgery was monitored and salvaged with the Compact-A Dideco, and postoperative blood loss with the BT 797 Recovery Dideco for the first 24 hours. Perioperative blood loss, frequency and quantity of transfusions were significantly higher in group D (p<0.0001). Total blood loss was reduced by 31.3% by epidural anaesthesia, 20.4% by Aprotinin and 51.4% using a combination of the two techniques.

Aged↗
PubMed1999

Coronary stenting in patients with situs viscerum inversus.

Atherosclerotic coronary disease may develop even in patients with complex cardiovascular anomalies who reach adult life. Coronary revascularization (surgical or interventional) may present potential difficulties related to the unusual anatomy. We describe two cases of situs viscerum inversus who underwent cardiac catheterization and angiography as adults because of ingravescent angina. The study identified the cardiac relations and connections, and diagnosed severe coronary disease that was successfully treated with coronary angioplasty and stent implantation. The implications of performing such procedures in patients with similar cardiac anomalies are discussed.

Angioplasty, Balloon, Coronary↗
PubMed1999

Improvement of myocardial ischemia by subclavian stent implantation in patients with internal mammary grafts: a case report and review of the literature.

In patients with coronary bypass which utilizes left (LIMA) or right internal mammary artery (RIMA), recurrent ischemia is often due to stenosis of the distal anastomoses of the grafts. However, occasionally, ischemia may be due to extracoronary causes, such as subclavian disease proximal to the internal mammary artery origins. This case report describes such clinical situation emphasizing the need for careful patient evaluation, and discusses therapeutic interventional options, in particular, safety and effectiveness of self expanding subclavian stent implantation. A review of the literature is also presented.

Humans↗