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Biomedical subjects

F Greco

Publications and source records attributed to F Greco.

At least 19 recordsLinked to original sources
PubMed2002

The stress tensor in entangled polymers.

In entangled polymeric liquids, a subchain connecting two entanglements is an open system which can exchange particles (Kuhn segments) with its neighboring subchains along the polymer chain. We present a calculation of the subchain mechanical behavior as determined from the grand canonical formalism of statistical mechanics, with different subchains in the same chain sharing the same chemical potential. It is shown that the linear monomer density is a constant, as originally inferred by Doi and Edwards, but the tension is generally different from one subchain to another. Accounting for the latter effect leads to a new tensorial strain measure, somewhat different from that proposed by Doi and Edwards.

Journal Article↗
PubMed2002

Androgen receptors in Dupuytren's contracture.

Palmar fascia tissue and cultured cells from patients with Dupuytren's contracture and from normal subjects were characterized and analyzed for androgen receptor expression. Androgen receptors have never been studied in Dupuytren's myofibroblasts and may have a role in its high male predominance. Surgical samples were collected from eight patients undergoing surgery for Dupuytren's contracture and from four patients with carpal tunnel syndrome, used as control tissue. Immunohistochemical analysis was performed on tissue samples and on cell cultures with anti-androgen receptor, anti-alpha-smooth muscle actin, anti-fibronectin, and anti-type I and III collagen antibodies using the biotin avidin peroxidase method as revelatory system. Immunostaining for androgen receptors in tissue samples and cultured cells revealed nuclear reaction in many Dupuytren's myofibroblasts, but in few fibroblasts of the normal palmar fascia. In a double-labeling study, androgen receptors were seen to co-localize with alpha-actin in both cell cultures and tissue samples. We present the first evidence that the palmar fascia is a target tissue for androgen action and that the expression of androgen receptors in Dupuytren's contracture is considerably higher than in the normal palmar fascia. Further studies will need to evaluate whether the androgen-responsive state of the tissue is related to the high incidence of Dupuytren's contracture in the male sex.

Actins↗
PubMed2002

Nasal and hearing impairment: are they linked?

Hearing impairment is the most prevalent sensory deficit in the human population. Otosclerosis and chronic otitis media are two of the most frequent causes of hearing loss of the Western world and both benefit from middle ear surgery. The success rate is high for both operations, in expert hands, but, in our clinic and in every ENT clinic, there remains a percentage of failure. Some of the most frequent post-operative complications can lead to tubal dysfunction. We believe that a correct and complete evaluation of the rhino-pharyngeal-tubal unit is very important before tympanoplasty and stapedioplasty in order to further reduce the incidence of some post-operative complications and to increase the success rate of middle ear surgery. What is well known in medicine, 'prevention is the best therapy', seems not oddly observed in ear surgery, where is usually operated the effect, while the evaluation and therapy of the causes seems to be underestimated.

Eustachian Tube↗
PubMed2002

Early-onset of septo-optic dysplasia. A case report with follow-up.

The case of a nine-month'old girl with septo-optic dysplasia is reported. The patient suffered in neonatal life from severe hypoglycemia, conjugated hyperbilirubinemia and nystagmus. At the age of 2 months ophthalmological examination revealed bilateral optic nerve hypoplasia; at the age of 9 months endocrinological investigations showed GH and ACTH deficiency and substitutive hormone therapy was started. MRI scans demonstrated dilatation of ventricles and pituitary ectopia. At the age of 27 months hypothyroidism due to TSH deficiency developed. The auxological and neurological follow-up is reported. The importance of direct ophthalmoscopy of the optic nerve in neonatal age is stressed: an early diagnosis can favourably influence the outcome of the disease.

Age Factors↗
PubMed2001

Magnetic resonance imaging of molecular transport in living morning glory stems.

MRI was applied to investigate the transport pathways in Morning Glory plant stems. The study was carried out on living plants without affecting their integrity. The architecture of a dicotyledonous plant was deeply characterized: the root system structure and the vascular bundle location were identified, the presence of central voids caused by cell maturation and loss were observed in the stem. Molecular transport components were recognized, by observing the concentration profile of a tracer, which changed with time after its absorption by the plant roots. MRI analysis revealed the presence of an axial transport as the progress of the tracer front through the vascular bundles and a radial molecular transport from the vascular bundles toward the surface of the stem. As a result, the tracer molecular transport formed the parabolic tracer front (PTF). A model was built up through the analysis of the PTF that consisted of an axial front at the peak position and a radial front at the width of the parabolic tail. PTF analysis revealed differences between the tracer transport velocities in the axial and the radial directions in the plant stem. The model revealed that the width of the parabolic tail reflected the magnitudes of diffusion and permeation of the tracer in the plant stem.

Biological Transport↗
PubMed2001

High-dose thiotepa and melphalan with hemopoietic progenitor support following induction therapy with epirubicin-paclitaxel-containing regimens in metastatic breast cancer (MBC).

BACKGROUND: Preliminary data from phase III randomized studies have failed to show benefit of HDC given as consolidation after anthracycline and alkylating-based chemotherapy in metastatic breast cancer (MBC). Moderate activity of induction regimens and selection of chemoresistant clones are among the possible reasons for these disappointing results. We therefore have designed a phase II study where high-dose alkylating agents are given as consolidation after an induction treatment including the most active agents (epirubicin and paclitaxel) without alkylating agents. PATIENTS AND METHODS: Patients with MBC not previously treated with chemotherapy for metastatic disease were eligible. After six courses of epirubicin-paclitaxel +/- gemcitabine patients received a course of thiotepa 600 mg/m2 + melphalan 160 mg/m2 with hemopoietic support. Pharmacokinetic parameters of thiotepa and melphalan were measured and related to treatment outcomes. The L-VEF of the patients was monitored before and after treatment. RESULTS: Forty-eight patients have been treated. Before HDC 14 patients were in CR, and 34 in PR. A median of 6.92 x 10(6) (range 1.53-16.6) CD34+ cells/kg were reinfused after HDC. Median days (range) to neutrophils > 0.5 x 10(9)/l and platelets > 20,000 x 10(9)/l were 9.5 (9-33) and 10 days (9-32), respectively. Symptomatic CHF was observed in two patients (4.1%). Cmax and AUC of thiotepa showed a linear relationship with time to progression (TTP) and overall survival (OS): r2 = 0.6. After HDC the conversion rate from PR to CR was 44.1%. At five years progression-free and overall survival rates are 37.5% and 65%, respectively. A treatment-related death was observed. CONCLUSIONS: High-dose thiotepa and melphalan after an epirubicin-paclitaxel-containing treatment is feasible, devoid of significant cardiotoxicity and very active. Pharmacokinetic parameters of high-dose thiotepa might be linked to treatment outcome.

Adult↗
PubMed2001

Hemihydranencephaly: case report and literature review.

Hydranencephaly is a severe brain condition characterized by complete or almost complete absence of cerebral cortex with preservation of meninges, basal ganglia, pons, medulla, cerebellum, and falx. It has been ascribed to different causes (infections, irradiations, fetal anoxia, medications, twin-twin transfusion), all leading to vascular disruption. Hemihydranencephaly is an extremely rare condition in which the vascular anomaly is unilateral. We report on a patient who was suspected to have hydrocephalus in utero; a brain magnetic resonance imaging scan showed left-sided hydranencephaly with preservation of basal ganglia. The patient developed signs of right hemiparesis but notably has only mild language delay. The available literature on hemihydranencephaly is reviewed.

Brain↗
PubMed2001

[Thrombolytic therapy during cardiopulmonary resuscitation for acute massive pulmonary embolism. A case report].

Massive pulmonary embolism associated with cardiac arrest has an extremely high mortality in spite of cardiopulmonary resuscitation maneuvers. An early diagnosis of pulmonary embolism as cause of cardiac arrest and a rapid specific therapy able to obtain a restoration of pulmonary flow can improve the prognosis. The authors report a case of cardiac arrest for massive pulmonary embolism promptly diagnosed by echocardiography and treated by thrombolytic therapy with an initial favourable outcome.

Acute Disease↗
PubMed2000

Isolated pulmonary hypertension in diffuse cutaneous systemic sclerosis successfully treated with long-term plasma exchange.

Isolated pulmonary hypertension (PHT) in patients with diffuse cutaneous systemic sclerosis (dSSc) is one of the most severe complication. Here we report the case of a 22 year-old white woman with anti-U3RNP antibody-positive dSSc complicated by severe, isolated PHT successfully treated with long-term plasma exchange. This beneficial effect persisted for two years, even after plasma exchange discontinuation. This is the first observation of isolated PHT in dSSc responsive to plasma exchange therapy.

Adult↗
PubMed2000

[The usefulness of the association of clinical probability, rapid plasma measurement of D-dimer, compression echography of the lower limbs and echocardiography in the diagnosis of acute pulmonary embolism].

BACKGROUND: The aim of this study was to investigate the diagnostic utility of clinical probability, rapid plasma D-dimer assay, compression ultrasonography (CUS) and transthoracic echocardiography (TTE) in patients with suspected pulmonary embolism. METHODS: One hundred forty consecutive outpatients with suspected pulmonary embolism were enrolled in a prospective trial. We evaluated sensitivity, specificity, positive and negative predictive value of a combination of clinical probability, D-dimer, CUS and TTE using perfusion lung scan and pulmonary angiography as a combined gold standard for determining the presence or absence of pulmonary embolism. Clinical probability was assessed in accordance with the PIOPED criteria. The D-dimer (Nycocard) level was considered as abnormal > 0.3 mg/l, the CUS if incompressibility of the leg veins was showed, and the TTE if right ventricular dilation was present, in the absence of chronic pulmonary disease. The combination of these tests was considered consistent with the presence of pulmonary embolism if D-dimer plus CUS and/or TTE showed abnormal results. A pulmonary embolism was excluded if D-dimer and CUS showed normal findings or a low clinical probability was associated with normal findings of CUS and TTE. RESULTS: One hundred eleven patients were evaluated. Pulmonary embolism was present in 45/111 (40%) patients. The combination of tests showed positive findings in 39/39 patients with pulmonary embolism, negative findings in 47/50 without pulmonary embolism and non-diagnostic results in 22/111 (20%) patients (95% confidence interval--CI 12-28%). There were three false positive and no false negative results. Sensitivity and specificity were 100 and 94% respectively (95% CI 92-100% and 87-100%); positive and negative predictive values were 93 and 100% (95% CI 85-100% and 93-100%). None of these tests, separately, showed enough sensitivity and specificity. CONCLUSIONS: The combination of clinical probability, D-dimer, CUS and TTE was highly accurate to confirm or rule out pulmonary embolism.

Acute Disease↗
PubMed2000

[Congenital abnormalities of the temporal bone. Clinical picture and therapeutic indications].

The embryology of the ear and the different congenital anomalies depending on the arrest in development at a particular embryologic date are reviewed. The historical and the actual attitude towards surgical correction is discussed. The classification system, the evaluation and patients selection, the timing of auricular reconstruction and atresiaplasty, the preoperative evaluation, the patient and parents counselling, the surgical technique, the complications and alternative techniques are discussed.

Craniofacial Abnormalities↗
PubMed1999

Experimental Determination of Drop Shape in Slow Steady Shear Flow.

Theoretical predictions for the 3D shape of a Newtonian drop immersed in a Newtonian fluid under slow flow have been available for a long time (C.E. Chaffey and H. Brenner, J. Colloid Interface Sci. 24, 258 (1967); J.M. Rallison, J. Fluid Mech. 98, 625 (1980)). The predictions contain four scalar coefficients, given in terms of the viscosity ratio of the component fluids. In this work, experimental values of such coefficients were measured for the case of two Newtonian fluids in simple shear flow. The experiments were carried out in a parallel plate apparatus, equipped with video-enhanced microscopy, and the measurements were performed by image analysis techniques. The results were also compared to theoretical calculations and provide the first complete assessment of shape predictions for the case of Newtonian fluids. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Pyrrolo[3,2-c]quinoline derivatives: a new class of kynurenine-3-hydroxylase inhibitors.

A series of pyrrolo[3,2-c]quinoline derivatives were synthesised and evaluated as inhibitors of selected enzymes of the kynurenine pathway. 7-Chloro-3-methyl-1H-pyrrolo[3,2-c]quinoline-4-carboxylic acid (7a) was found to be a relatively potent and selective inhibitor of kynurenine-3-hydroxylase (KYN-3-OHase). A molecular modelling study showed a good superimposition of 7a with PNU-156561 and kynurenine the natural substrate of KYN-3-OHase.

Animals↗
PubMed1999

Elastic fibers of musculoskeletal tissues in bovine Marfan syndrome: a morphometric study.

Bovine Marfan syndrome has all the major pathognomonic, clinical, and pathological features of the human syndrome. To further explore the alterations characterizing Marfan syndrome, musculoskeletal tissues from affected and healthy cattle were subjected to histochemical and histomorphometric analysis. Our findings demonstrated reduced elastic fiber content in the periosteum, capsule, interosseous ligament, and flexor tendons of the metatarsophalangeal joint of affected cattle. The elastic properties of a tissue are supplied by elastic fibers in the extracellular matrix; therefore, their reduced content in articular tissues suggests that these fibers could be functionally incompetent to withstand normal stress, causing a predisposition to joint laxity and dislocation. Moreover, perichondrial-periosteal membranes, which are made of collagen and elastic fibers, are known to affect the growth process of the long bones. The decrease in the number of elastic fibers in these membranes could result in reduced restraint of skeletal growth and explain some skeletal abnormalities of Marfan syndrome (i.e., dolichostenomelic habitus).

Animals↗
PubMed1999

N,N-dicarboxymethyl chitosan as delivery agent for bone morphogenetic protein in the repair of articular cartilage.

Bone morphogenetic protein (BMP), associated with N,N-dicarboxymethyl chitosan, is used to induce or facilitate the repair of articular cartilage lesions. This association is intended for the synergistic potentiation of the respective biological effects. Data show that BMP-7 enhances the in vivo proliferation of cells with chondrocytes phenotype in the articular environment, leading to partial healing of the articular surface of the lesions. N,N-dicarboxymethyl chitosan is found to be useful as a molecular carrier or drug delivery agent.

Animals↗