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Biomedical subjects

L Castellani

Publications and source records attributed to L Castellani.

At least 73 records · Page 4Linked to original sources
PubMed1986

[Peroperative endoluminal dilatation or recanalization (DELPO or RCPO) in arteriopathies of the lower extremities. A new therapeutic weapon for the vascular surgeon. Apropos of 42 cases].

Forty-two DELPO or RCPO were performed using coaxial balloon catheters through surgical vascular approach for 35 cases of advanced lower limb arterial disease (stages: pronounced II: 6, III: 13, IV: 12, subacute ischemic: 4). The DELPO involved the following arteries: iliac: 12, deep femoral: 3, superficial femoral: 12, popliteal: 5, leg artery: 8, stenosis of popliteal anastomosis: 2, and was combined with a reconstructive arterial operation in 26 cases (proximal: 11 times, distal: 14 times or intersegmental: twice in relation to the surgical procedure). The DELPO was conducted alone in 9 cases and the RCPO alone in 6 cases, the surgical approach being preferred to the percutaneous route. Early results were rated as good in 89%, with clinical failures requiring amputation in 4% and failure of the method in 7%. The DELPO allows two objectives to be reached. First, when combined with a surgical procedure it reduces the extent and therefore the degree of surgical aggression while creating improved hemodynamic conditions for vascular reconstruction (improved proximal or distal beds or both). Second, when performed alone DELPO or RCPO enable safe, reliable treatment of lesions usually approached by a percutaneous endoluminal dilatation procedure.

Aged↗
PubMed1985

Dimer ribbons in the three-dimensional structure of sarcoplasmic reticulum.

The three-dimensional structure of scallop sarcoplasmic reticulum membranes has been determined from electron micrographs of two classes of stain-filled tubules by helical reconstruction methods. These structures are characterized by dimer ribbons of Ca2+-ATPase molecules running diagonally around the tube wall. Deep right-handed grooves separate the ribbons. The elongated, curved units of the dimer (approximately 95 A long in the radial direction; 60 to 70 A axially, and about 30 A wide) are displaced axially by approximately 34 A and are connected at their outer ends by a bridge running nearly parallel to the tube axis. The monomers make a second contact at their inner ends. Adjacent units with the same orientation form a strong contact that is responsible for the ribbon appearance. Comparison of tubules of different diameter shows that one set of connections between the dimer ribbons is conserved: the inner ends of axially displaced dimers appear to make contact along a left-handed path almost perpendicular to the major grooves. The lipid bilayer cannot be clearly identified. The two-dimensional map obtained from flattened tubules is consistent with the three-dimensional reconstruction in showing dimer ribbons connected by a weak contact across the grooves, strongly resembling the inter-dimer bond observed in three dimensions. The two-dimensional map shows a 2-fold axis relating units of the dimer, but the three-dimensional tubes show a slight axial polarity that may arise from the presence of proteins other than the Ca2+-ATPase.

Animals↗
PubMed1985

Ordered arrays of Ca2+-ATPase on the cytoplasmic surface of isolated sarcoplasmic reticulum.

Isolated sarcoplasmic reticulum (SR) vesicles with polymerized calcium pump protein were freeze-dried and rotary shadowed following uranyl acetate stabilization. This technique allows direct observation of a single side of the vesicle without requiring optical filtering. The heads of individual ATPase molecules, projecting above the cytoplasmic surface, are clearly resolved in the replicas. Ca ATPase molecules form extensive arrays in vanadate-treated, rabbit SR vesicles and in gently isolated, native SR vesicles from scallop. Gentle isolation results in limited areas of orderly structure in native SR isolated from vertebrate muscles. Special attention is given to the effect of various shadow thicknesses on the appearance of the heads. This information is essential to the interpretation of images in the accompanying paper (Franzini-Armstrong, C., and D.J. Ferguson, 1985, Biophys. J., 48:607-615).

Acetates↗
PubMed1984

Serum and sputum concentrations of azlocillin, cefoperazone and ceftazidime in patients with cystic fibrosis.

Single-dose pharmacokinetics of azlocillin, cefoperazone and ceftazidime were studied in 17 patients with cystic fibrosis (CF). All patients had broncho-pulmonary infections caused by Pseudomonas aeruginosa. Three groups of five, six, and six patients were treated with azlocillin, cefoperazone, or ceftazidime, respectively. The size of the single dose was 133 mg/kg for azlocillin, 66.7 mg/kg for ceftazidime and 66.7 mg/kg for cefoperazone. The clearance values for the three antibiotics calculated from the single-dose data were, on the average, higher than the values previously reported for normal subjects. After the first dose, the patients received a repeated-dose treatment with the same antibiotic. During the first 5 days of therapy, a complement postural drainage of sputum was obtained four times a day for each patient. Cefoperazone could be measured in 47 (39.2%) of the 120 sputum samples assayed while ceftazidime was shown to be present in all 120 sputum samples examined. Azlocillin was not detected in any of the 100 sputum samples assayed.

Adolescent↗
PubMed1983

Structure of myosin/paramyosin filaments from a molluscan smooth muscle.

Small-angle X-ray diffraction patterns of chemically skinned pedal retractor muscles from Mytilus (PRM) in the relaxed state show a set of diffuse off-meridional reflections that arise from a helical array of myosin crossbridges with 8/3 screw symmetry. Experiments involving extraction of myosin as well as analysis of the rigor pattern have been used to confirm the origin of these reflections. The relatively high myosin/paramyosin molar ratio (1.3 to 1.6) in PRM compared to other molluscan smooth muscles may account for the observation of the relatively stronger diffraction from the myosin array. Thick filaments isolated from PRM and contrasted by negative staining for electron microscopy appear to be very long (up to 17 micron), and to have a rather small diameter (about 40 nm at the center); they taper gradually toward the ends. These filaments show a clear transverse band pattern repeating at 14.4 nm and elongated projections (crossbridges) at the surface except in the central bare zone. Optical diffraction patterns show reflections from crossbridges consistent with the X-ray patterns of the relaxed whole muscle. Filaments unidirectionally shadowed with platinum show diagonal striations running at an angle of about 17 degrees to the filament axis, revealing that the crossbridges are arrayed in a right-handed helix. The paramyosin core is clearly seen upon extraction of myosin. Observations on both negatively stained and sectioned material are consistent with the results of Elliott (1979) and Bennett & Elliott (1981) suggesting a layered structure of the core. Cores stripped of myosin, however, appear to undergo some distortion indicating that the three-dimensional structure is not yet completely solved. The assembly of these thick filaments presents intriguing structural problems since the myosin surface lattice does not appear to have the same symmetry as the underlying paramyosin core.

Animals↗
PubMed1983

X-ray absorption near edge structure (XANES) determination of calcium sites of troponin C and parvalbumin.

Using synchrotron radiation at the Frascati storage ring ADONE, the X-ray Absorption Near Edge Structure (XANES) has been applied to determine homologies and modifications of the local structure of the calcium binding sites of troponin C. In all four calcium binding sites, Ca2+ appears to be co-ordinated to carboxyl and carbonyl groups in a characteristic configuration. No structural difference has been found between high and low-affinity sites. A distortion of the Ca2+ site geometry by binding of Mg2+ has been observed. The XANES of parvalbumin has been measured and found to be different from troponin C. A tentative identification of the characteristic XANES spectra of the two different Ca2+ sites in this protein is reported.

Amino Acid Sequence↗
PubMed1983

Crystalline structure of sarcoplasmic reticulum from scallop.

Negatively stained sarcoplasmic reticulum from the scallop Placopecten magellanicus presented a variety of crystalline forms, the most common being tubular structures. These were characterized by paired rows of morphological units, spaced at approximately 120 A, running diagonally across the tubules. The orthogonal unit cell (120 X 55 A) contained two units, related by a twofold axis, which probably represented the part of the Ca2+-ATPase molecule projecting from the outer surface of the membrane.

Animals↗
PubMed1983

Alternative antibiotics for the treatment of Pseudomonas infections in cystic fibrosis.

We have investigated the effectiveness of seven new beta-lactam antibiotics, azlocillin, piperacillin, ceftazidime, cefsulodin, cefoperazone, latamoxef (moxalactam), and cefotaxime, against acute pulmonary exacerbations caused by Pseudomonas aeruginosa in cystic fibrosis. Three hundred and fifty-five strains of Ps aeruginosa isolated from 310 sputum cultures (190 cystic fibrosis patients) were tested for susceptibility to the drugs by determination of minimal inhibitory concentrations (MIC). The highest activity was shown by ceftazidime (6% resistant strains) followed by cefsulodin and piperacillin (15 and 16% resistant strains); very low activity was found for cefotaxime and latamoxef (moxalactam). Ceftazidime was the most active drug against 32 pseudomonas isolates that were resistant to both carbenicillin and aminoglycosides (78% susceptible). A randomized, double-blind trial of azlocillin, piperacillin, ceftazidime, cefsulodin or cefoperazone was performed in 111 cystic fibrosis patients with predominant and susceptible pseudomonas in their sputum. Results were evaluated by a clinical, radiological and bacteriological scoring system: the best results were obtained with ceftazidime, followed by cefsulodin and piperacillin. However, pseudomonas was eradicated in only 22 (23%) of the cases with the most active drugs and persisted or reappeared in all the cases 1 to 3 months later. Ceftazidime always eradicated Staph. aureus and Haemophilus influenzae associated with pseudomonas. Similar eradication occurred nearly always with cefsulodin but rarely with the other drugs. No serious drug reaction occurred but a later fever and rash with piperacillin, transient diarrhoea with cefoperazone, vomiting with cefsulodin, and very frequent eosinophilia with ceftazidime should be mentioned. These five drugs offer, in varying degree, alternatives to traditional anti pseudomonas antibiotics in cystic fibrosis pulmonary infections, but they should be used only against well-proven resistant strains. Ceftazidime is best and cefotaxime and latamoxef (moxalactam) least useful.

Adolescent↗
PubMed1983

[Surgical treatment of congenital aortic valve constriction with associated obstructive cardiomyopathy. Perioperative left intraventricular gradient treated with beta blockers. Apropos of a case].

The authors report a case of congenital valvular aortic stenosis associated with echocardiographic and angiographic appearances of hypertrophic obstructive cardiomyopathy. After valvular replacement and partial myotomy a high intraventricular pressure gradient (125 mmHg) with low intra aortic pressure was recorded. High dose intravenous propranolol (25 mg in 2 hours) reduced this gradient to 50 mmHg allowing cardiopulmonary bypass to be discontinued. This clinical combination is associated with a risk of aggravation of the intra-ventricular obstructive phenomenon when the obstacle to left ventricular ejection is relieved: surgical myotomy was performed in similar, previously published cases. High doses betablocker therapy can be performed in similar, previously published cases. High dose betablocker therapy can be useful in this association and it may also be instituted when right intraventricular pressure gradient increase after relief of pulmonary valvular stenosis.

Adolescent↗
PubMed1981

Structure of filamin and the F-actin-heavy merofilamin complex.

Rotary-shadowed filamin molecules appear as long, highly flexible rods curved into a variety of configurations. The particles observed were 2.7 nm wide but had contour lengths of either 98 nm or 193 nm. The longer particles are probably end-to-end dimers of the shorter but it is not clear how many polypeptide chains these particles contain. Heavy merofilamin, obtained by digestion of filamin with a calcium-activated protease from muscle, has been used to investigate where filamin binds on the actin filaments. Negatively stained filaments of actin plus heavy merofilamin resemble those of pure actin; occasionally rod-shaped material sticking out from the filament is observed suggesting that the elongated shape of filamin is maintained after digestion. Optical diffraction patterns of electron micrographs of paracrystals of actin plus heavy merofilamin indicate that the helical symmetry of the actin filament is unchanged, but the observed interfilament spacing is larger than in F-actin paracrystals. Increased intensity of the second layer-line reflection is observed, suggesting that additional material is lying along the grooves of the actin helix. The elongated shape of filamin and its ability to bind to F-actin in a way similar to tropomyosin suggest a possible role for this protein in regulating the organization and aggregation of actin filaments.

Actins↗
PubMed1978

Nerve growth factor potentiates actomyosin adenosinetriphosphatase.

The nerve growth factor protein (NGF) favors polymerization of brain actin and induces its organization to form paracrystalline structures that activate myosin ATPase (ATP phosphohydrolase, EC 3.6.1.3) to an extent greater than actin alone. Binding studies show that the initial 1:1 stoichiometry of NGF-G-actin complexes decreases to 1:7-10 when polymerization is ended and paracrystalline structures are formed. The ratio becomes even lower when heavy meromyosin is added in the absence of ATP, suggesting that heavy meromyosin displaces NGF bound to actin microfilaments. This conclusion is supported by the finding that when heavy meromyosin is added to NGF-microfilament complexes, under conditions for "decorating" microfilaments, the usual paracrystalline structure of the complexes disappears. The NGF-mediated organization of actin and activation of myosin ATPase is visualized as a self-regulatory and self-propagating mechanism, because progressive displacement of the growth factor induced by heavy meromyosin binding to F actin as ATP consumption proceeds renders an increasingly higher amount of NGF free for new interactions. These findings are discussed in the light of the mechanism of action of NGF in the target cells.

Actins↗
PubMed1978

Fine structure and cytochemistry of the morphogenesis of round-headed human sperm.

Ejaculates and testicular biopsies of two infertile men were examined at ultrastructural and cytochemical levels. The two patients presented spermiograms in which all the spermatozoa had globular heads. Wide Golgi areas and large masses of annulatae lamellae were evident during spermatogenesis. Abnormal acrosomal vesicles were evident during early spermatid stage. Among the late spermatids, there was a small group characterized by a fibrous sheath showing considerable malformation, and "spindle shaped body." In Sertoli cells, detached acrosomes undergoing degeneration were noted. Low TPPase activity was found in Golgi complex and in abnormal acrosomal vesicles of early spermatids. As regards acid phosphatase, was localized in spermatocytes and in early spermatids, but not in late spermatids and mature spermatozoa. Leydig cells had high phosphatase activity.

Acid Phosphatase↗