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Biomedical subjects

P Mancini

Publications and source records attributed to P Mancini.

At least 55 records · Page 3Linked to original sources
PubMed1994

Extracorporeal CO2 removal in a lung lavage model of respiratory failure.

Extracorporeal life support (ECLS) is a recognized treatment for neonatal respiratory distress unresponsive to other forms of therapy. Variations of this technique are being developed in an effort to extend its applicability and safety. Extracorporeal CO2 removal (ECCO2R) is one such modification that requires blood flows of 20% to 50% of cardiac output and therefore lends itself to percutaneous venous cannulation. The authors evaluated ECCO2R in conjunction with low-frequency ventilation, using a lung lavage-induced model of respiratory failure in rabbits. Six rabbits were lavaged an average of 9 times with 15 mL/kg Plasma-Lyte A at 37 degrees C via an endotracheal tube. Incremental ventilatory changes were made during lavage, to an FIO2 of 1.0, rate of 80, peak inspiratory pressure (PIP) of 37 cm H2O, and positive end-expiratory pressure (PEEP) of 4 cm H2O. Arterial blood gas values of PaO2 < 40 mm Hg and PaCO2 > 60 mm Hg resulted, meeting our criteria for respiratory failure. The rabbits were placed on veno-venous ECCO2R using a 0.8-m2 hollow fiber oxygenator and a commercially available double-lumen dialysis catheter. Blood flows of 10 to 20 mL/kg/min were used to manage CO2 removal. A low-frequency ventilation technique was employed using an FIO2 of 1.0 and a rate of 5 breaths per minute. PEEP was increased incrementally to maintain the PaO2 above 80 mm Hg. After initiation of ECCO2R, the arterial PaO2 increased to 165 +/- 109 mm Hg, with PEEP above 15 cm H2O, and PaCO2 decreased to 37 +/- 5 mm Hg, with a bypass flow rate of 15 mL/kg/min.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Identification and localization of the GM1 ganglioside in the cochlea using thin-layer chromatography and cholera toxin.

Using high-performance thin-layer chromatography, we identified GM1, GM3, GD3, GD1a, GT1b, GQ1b, and other gangliosides in chinchilla cochlea and cerebellum. GM1 was also identified on chromatograms with the B-subunit of cholera toxin (BCT). BCT was also used to determine the distribution of GM1 in fixed and unfixed tissues from cochlea, cerebellum, and sciatic nerve. Positive control tissues showed expected labeling of GM1 by BCT. Negative controls showed expected suppression of BCT binding to GM1 after GM1 extraction and GM1 absorption. In the cochlea, GM1 appeared abundant in plasma membranes of most epithelial cells lining the endolymphatic surface of the scala media, including the interdental, inner supporting, pillar, Deiters, Hensen, Claudius, Boettcher, spiral prominence, and external sulcus. GM1 appeared less abundant in cells of the stria vascularis, Reissner's membrane, and in nerve fibers. In hair cells, the stereocilia appeared to contain GM1; however, the endolymphatic surface of the cuticular plate and the body of the outer hair cells appeared to contain little GM1. In addition, the tectorial membrane, connective tissue of the spiral limbus, and amorphous layer of the basilar membrane also appeared to contain little GM1. Enzymatic degradation of glycoproteins and transformation of polysialogangliosides to GM1 increased the reactivity of BCT to cochlear GM1. This further supported the presence of GM1 and other gangliosides in the cochlea. Although the functional significance of GM1 and other gangliosides in the cochlea is not yet known, they are likely to play important roles in membrane function.

Animals↗
PubMed1993

Localization of the GM1 ganglioside in the vestibular system using cholera toxin.

Cholera toxin is an ubiquitous activator of intracellular adenylate cyclase and is divided in two major components: A and B. The B-component consists of several subunits that specifically bind to the external cell membrane. The receptor for the toxin, the GM1 ganglioside, is concentrated in nervous tissues. The B subunit of the cholera toxin, conjugated to different molecules (i.e., choleragenoid) is therefore a sensitive anatomical tracer and has been used to detect the presence of GM1 in mammalian tissues. Using choleragenoid, unlabeled and labeled with FITC, we have determined the distribution of the GM1 ganglioside in the vestibular system of the chinchilla. Vestibular tissues were fixed in 4% paraformaldehyde in phosphate buffer, decalcified in 10% EDTA and prepared as either whole-mount, surface-preparations, or for radial cryosections. Positive control tissue consisted of binding to normal brain tissues. Negative controls consisted of several treatments: masking of the GM1 receptors with unlabeled choleragenoid, tissue extraction of GM1 using ethanol, and preabsorbing the choleragenoid with bovine GM1. In addition, to exclude staining of glycoproteins that may have a carbohydrate structure similar to GM1, tissues were digested with trypsin prior to choleragenoid exposure. In the vestibular system, a strongly positive reaction was observed in: the sensory stereocilia and supporting cells of the maculae and cristae, epithelial cells of the planum semilunatum, and polygonal cells of the semicircular canal. Positive but less strong reactivity was observed in the sensory cell body of maculae and cristae, nerve fibers, epithelial cells of utricle and ampulla walls and flattened epithelial cells of the semicircular canals. No reactivity was present in the supporting connective tissue cells and fibrils, blood vessels, gelatinous cupula of the cristae ampullaris and statoconial membranes. Brain tissue showed strong choleragenoid reactivity. The negative controls showed no or greatly reduced reactivity to choleragenoid. Trypsin digestion did not decrease reactivity to choleragenoid.

Animals↗
PubMed1993

[The Nissenkorn endourethral prosthesis: our experience].

The Authors report their experience about 40 patients who presented urinary retention by cervico-prostatic obstruction with anesthetic counterindications or limited life expectancy, cured with the urethral prosthesis of Nissenkorn (IUC). Our data permit to say that in selected patients IUC may represent an effective treatment with minimal invasiveness, low cost and few side effects.

Aged↗
PubMed1993

[Three-dimensional computerized modelling of anatomical structures by computerized tomography imaging].

The authors built an automatic CT-driven device by which 3D models of biologic structures can be obtained. Original bidimensional densitometric data are recorded on tape and transferred to a mechanical computer-driven arm capable of cutting polystyrene slices reproducing the original biologic structures by means of an original software. The aim of our research was to assess the feasibility of such a device from a practical point of view and to analyze and solve related problems, in order to use the experience thus gained to develop more complex systems. We deliberately set up a device both technologically advanced and simple to be used even by non-specifically trained operators. The system capabilities open new perspectives in many application fields, such as surgery (stereotactic procedures, the making of personalized prostheses, plastic surgery, procedures planning and simulation), treatment (stereotactic radiotherapy), diagnostics (stereotactic biopsy) and educational use.

Humans↗
PubMed1993

[Echography in the follow-up of patients receiving an endoscopic injection of teflon for vesico-renal reflux].

The surgical treatment of vesicorenal reflux implies open surgery and consequently an hospitalization. The sub-ureteric injection of poly-tetra-fluoro ethylene (Teflon) for correction of vesicorenal reflux was first utilized in 1981 by Matouschek. We have reviewed our personal experience with endoscopic correction of vesicorenal reflux from 1985 to 1990 and evaluated the importance of ultrasonography especially in the follow up.

Adolescent↗
PubMed1993

[Echo-guided puncture of intraprostatic cysts: our experience].

Prostatic cysts are a pathological condition which is rare and still poorly known. In the past a precise diagnosis was difficult and was made with radiologic examination and/or cystoscopy and/or surgery. Up to date echotomography is the most important technique not only for the diagnosis but also for the treatment of prostatic cysts. The Authors relate upon their experience about diagnosis and treatment of prostatic cysts.

Cysts↗
PubMed1993

[Echographic localization and monitoring of bladder calculi treated with ESWL].

The standard treatments for bladder stones consist either of an open operation or endoscopic transurethral disintegration and extraction. These treatment require anesthesia and hospitalization. We report our experience of ESWL monotherapy in the treatment of 10 patients affected by bladder stones. Our early datas show that ESWL for bladder stones is a safe an effective therapy which can be performed without the use of anesthesia in an outpatient basis.

Adult↗
PubMed1992

Sensory disorders of the lower urinary tract: urodynamic evaluation.

Sensory disorders of the lower urinary tract (urethral syndrome, prostatodynia, painful pelvic-perineal syndromes, trigonitis) are clinically frequent, however this diagnosis is possible only by excluding other pathologies after clinical and instrumental evaluation. The Authors report their experience in urodynamic evaluation of sensory disorders of the lower urinary tract and they discuss about the absence of a typical urodynamic pattern of sensorial pathology.

Female↗
PubMed1991

Partition of epidermal growth factor receptors on freeze-fractured plasma membranes of A431 cells is affected by the ligand.

The fracture immunolabel technique, which permits assessment of the partition of transmembrane proteins with the inner or outer leaflets of the freeze-fractured membrane, was used to analyze the behavior on fracture of epidermal growth factor (EGF) receptors over the plasma membranes of A431 cells. The receptors partition mainly with the outer leaflet of the freeze-fractured plasma membranes, whereas they become associated with the inner leaflet when they are occupied by the ligand. This modified partition is even more evident after receptor clustering induced by incubation with EGF at 37 degrees C. Treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) decreases the number of receptors over both inner and outer leaflets. An effect similar to that induced by the ligand is obtained when receptor aggregation is achieved using anti-receptor monoclonal antibodies (MAb). The modified partition therefore indicates receptor activation and appears to be a consequence of receptor cross-linking rather than to reflect a conformational change of the receptor molecule. Parallel immunolabeling with anti-phosphotyrosine antibodies of freeze-fractured EGF-treated A431 cells reveals that the receptors, when activated, are associated only with the inner leaflet of the plasma membrane.

Cell Line↗
PubMed1990

High-resolution surface views of human lymphocytes during capping of CD4 and HLA antigens as revealed by immunogold fracture-flip.

The surface ultrastructure of lymphocytes during capping of two transmembrane proteins is shown. As seen by fracture-flip the plasma membranes of human lymphocytes are covered by a high density of surface particles. Incubation in 30% glycerol leads to aggregation of these surface particles. Immunogold labelling shows that the transmembrane proteins bearing HLA class I and CD4 antigens are confined to the particle aggregates. These results indicate that surface particles revealed by fracture-flip represent surface protrusions of integral membrane proteins seen as intramembrane particles in freeze-fractured lymphocytes. During capping HLA or CD4 antigens aggregate into progressively larger patches and, finally, into single caps. As revealed by fracture-flip the patches/caps are seen as clearly differentiated raised platforms that are clearly and sharply demarcated relative to contiguous areas of the surface. In non-patched (non-capped) regions, the pattern of distribution and apparent density of surface particles remain unaltered. Immunogold labelling clearly demarcates patches and caps, and shows that virtually no antigen molecules remain dispersed over the non-patched (non-capped) regions. Estimates of the surface density of either HLA or CD4 antigens over the capped areas point to high planar concentrations of the transmembrane proteins that bear these antigens.

Antigens, Surface↗
PubMed1990

[Bidirectional tachycardia. Physiopathogenetic considerations and therapeutic strategy].

The authors report two cases of bidirectional ventricular tachycardia in patients suffering from digitalis intoxications. Considered the severe prognosis of such arrhythmias, the importance of an early diagnosis for starting an exact therapeutic strategy is stressed. It is important to note the absolute contraindication at the use of cardioactive glucoside. The various pathogenetic hypotheses about this arrhythmias are reviewed.

Adult↗
PubMed1990

[Electrocardiographic evaluation of myocardial co-involvement in Duchenne muscular dystrophy: prognostic implications in a case with multiple localizations].

After a review of the literature on myocardial involvement (MI) in Duchenne's progressive muscular dystrophy (DMD), the authors report a case with an extensive MI. This severe myocardial functional impairment is a poor index in the prognosis of DMD. The authors emphasize the use of echocardiography in the screening of MI in DMD.

Adolescent↗
PubMed1989

Molecular cytochemistry of CD3 and CD4 antigens in human lymphocytes as studied by label-fracture and by fracture-label.

Label-fracture and fracture-label membrane immunocytochemistry are used to analyze the surface distribution, dynamics and partition on fracture of CD3 and CD4 antigens of human T lymphocytes. Redistribution of the antigens, induced by treatment at 37 degrees C with specific monoclonal antibodies, results in patching and capping of the labeling as observed in label-fractured specimens. Examination of platinum/carbon replicas of freeze-fractured plasma membranes of antibody-treated cells does not reveal recognizable domains of intramembrane particles. However, in cells where the aggregation of intramembrane particles is induced by incubation with glycerol, colloidal gold-labeled CD3 and CD4 molecules are seen confined to particulate domains of the membrane. Therefore, the lack of visible aggregation of intramembrane particles in patched or capped regions of the membrane implies that migration of CD3 and CD4 antigens with concentration in domains of the membrane is achieved contemporaneously with export of other non-capped integral membrane proteins from the same regions, in a process of diffusional equilibrium. Examination of fracture-labeled specimens shows that CD4 molecules partition on fracture with the inner protoplasmic face of the plasma membrane. This partition illustrates the transmembrane attitude of the antigen molecule and is a probable consequence of interaction of the protein with other components of the membrane or with the cytoskeleton.

Antibodies, Monoclonal↗