Biomedical subjects
Publications and source records attributed to P Valenti.
A series of 2-substituted 1,4-dihydropyridines with a xanthone backbone was prepared. The compounds were evaluated for inotropic, chronotropic and calcium antagonist properties.
Chromone, flavone and xanthone analogues of geiparvarin (1) are described. Compounds 2a and 2b are more active in inhibiting the proliferation of F10 metastatic murine melanoma cells. In particular, 2a is 13 times more active at microM concentration after 48 h exposure.
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Clinically relevant Streptococcus spp. were tested for their susceptibility towards human serum transferrin (TR) and lactoferrin (LF). Neither clinical isolates or type strains were inhibited by transferrins (5 mg/ml). All species tested were shown to be able to grow under iron-limiting conditions (< 0.1 microM) and this might account for the lack of TR or LF activity towards streptococci. Even if not sensitive to LF and TR, some species were shown to bind LF in the apo-form.
30 asymptomatic volunteer subjects and more than 400 patients with suspected rotator cuff lesions were examined by MRI at 0.5 T using T2*-PD weighted gradient echo (T2-GEI) sequences. Its superiority over T2 spin echo imaging was established in previous studies. The results were compared to those of surgery in 87 cases and arthrography in 233 cases (associated with CT arthrography in 70 cases). In the operated patients, T2-GEI and arthrography correctly diagnosed 49 complete ruptures (CR). T2-GEI was found to be superior to arthrography for defining the real extent of the rupture, the degree of tendon retraction and the local muscular trophicity, essential information to define the therapeutic indications. In contrast, among 22 lesions of the long biceps tendon, correctly demonstrated by arthrography or CT arthrography, 5 intracapsular lesions were not detected by MRI. MRI was able to detect 8 lesions of the anterior labrum associated with a CR not demonstrated by arthrography. Lastly, among the 18 cases of partial inferior rupture (PIR), 6 partial superficial ruptures and 14 cases of inflammatory changes, correctly diagnosed by MRI, only 8 PIR were also demonstrated by arthrography. For the non-operated patients investigated by the two modalities (146 cases), T2-GEI and arthrography were concordant in 43 cases. In contrast, 103 intact cuffs on arthrography showed features on T2-GEI compatible with tendinopathy without rupture, bursitis and degenerative changes. In the absence of very fine surgical or histological correlations for these small lesions, it is impossible, at the present time, to determine the real sensitivity and specificity of MRI.
A series of xanthone 1,4-dihydropyridine derivatives were prepared. The compounds were evaluated for inotropic, chronotropic, and calcium antagonist properties.
We investigated the effect of some eucaryotic cytoplasmic structure and function inhibitors on the entry into HeLa cells of the Escherichia coli HB101 K12 strain, harbouring the recombinant plasmid pRI203, in which is cloned a 3.2 Kb chromosomal fragment of Yersinia pseudotuberculosis. Substances impairing microfilament structures and functions (cytochalasin B and trifluoroperazine) significantly reduced invasion ability whereas microtubule organization inhibitors (colchicine and vinblastine) were ineffective. Data obtained with a lipophilic weak base (methylamine), which raises the pH of intracellular vesicles, demonstrated that, in entry pathway of E. coli HB101 (pRI203), endosome acidification is not required. Host cell energy has been shown to contribute to bacterial internalization since the presence of oxidative phosphorylation and glycolysis inhibitors (sodium azide, 2-dinitrophenol and 2-deoxy-D-glucose) during the invasion process, affected bacterial entry.
A series of fluorenone and benzophenone 1,4-dihydropyridine derivatives were prepared. The compounds were evaluated for inotropic, chronotropic and calcium antagonist properties.
Vesiculodeferentography (VDG) plays an important role in diagnosing male infertility and staging of prostatic cancer; the techniques of performing the examination are, today, well codified: 1) retrograde, by endoscopic cannulation of ejaculatory ducts; 2) anterograde, by cannulation of the deferent duct surgically prepared at the scrotum. In order to avoid the difficulties of the first method and the risks in the second (like stenosis and fibrosis of the deferent duct) we propose a new simple and safe method based on the direct transperineal puncture of the seminal vesicle under direct echographic control with a transrectal probe. We have studied 16 patients, mainly in order to stage prostatic cancer; the procedure was easy to perform, well tolerated and without consequences at seminal level. It required only 30 minutes, without anaesthesia and with a very low cost. The method permits a clear visualisation of anatomical structures and of possible pathologies with particular reference to vesicular invasion by a prostatic cancer.
The recombinant plasmid pRI203 carries a Yersinia pseudotuberculosis chromosomal gene that makes E. coli K-12 HB101 strain able to synthetize an outer membrane protein, invasin, which interacts with integrin receptors of eukaryotic cells, enabling this microorganism to penetrate human cultured animal cells. In this study we evaluated the involvement of HeLa cell membrane structural components in the early phases of the invasive pathway of E. coli HB101 (pRI203). When HeLa cell monolayers were treated with several enzymes we showed that trypsin-, proteinase K- and neuraminidase-sensitive components are required for bacterial invasion. Comparison of the ability of simple and complex carbohydrates to inhibit bacterial invasion indicated that N-acetyl neuraminic acid, N-acetyl glucosamine and mucin were the most effective competitive inhibitors. Among glycolipids, gangliosides enhanced bacterial entry in HeLa cells. The results obtained suggest that N-acetyl neuraminic acid and N-acetyl glucosamine-containing glycoproteins and/or glycolipids participate as putative HeLa cell binding sites for the penetration process of E. coli HB101 (pRI203).
The authors have reviewed the results of the operative repair of 37 injuries of the axillary nerve. In 25 patients only the axillary nerve was injured, in 8 the suprascapular nerve was also damaged and in a further 4 the musculocutaneous nerve had also sustained injury. There was an associated anterior dislocation of the shoulder in 10 patients and a fracture was present in 8. Eleven patients out of 25 had a nearly normal range of abduction in spite of paralysis of the deltoid muscle, and this accounted for delay in diagnosis. Operation was undertaken 8 months after injury using a combined anterior and posterior approach. In 34 patients disruption of the nerve had occurred in relation to the quadrilateral space. In 32 cases nerve grafts were employed, in 2 direct suture and 1 underwent neurolysis. The results were good or very good in 23 out of the 25 direct repairs of isolated axillary lesions, and in all 4 patients with associated injury to the musculocutaneous nerve. Only 4 good results were obtained in the 8 patients who also had injuries to the suprascapular nerve. The results suggest that repair should be carried out early at between 3 and 6 months. E.M.G. studies are necessary before operation for proper assessment of nerve recovery.
Osteochondritis dissecans is a transchondral fracture. Localization to the elbow is rare when it is usually located in the capitellum of the humerus or the radial head. Osteochondritis of the trochlea of the humerus is described in a 12 year old X-ray and MRI.
The growth inhibiting activity of transferrins, citrate, 2-2' dipyridyl and desferrioxamine methanesulphonate towards Legionella spp. and their serogroups was investigated. The inhibitory activity of all these compounds depended upon the iron-free state of the molecules and was abolished by saturation with iron. No bactericidal effect by transferrins was observed at concentrations up to four times the minimal bacteriostatic concentration. No interaction of transferrins with the legionella cell surface was detected by direct or indirect fluorescence assay, or by dialysis culture experiments in which transferrin was separated from the bacterial cells. The demonstration of a siderophore-like activity in supernates of iron-deficient legionella cultures may account for the ability of Legionella spp. to multiply in conditions of iron restriction.
In the present paper, we demonstrated that low concentrations of various polycationic agents sensitize E. coli HB 101 harboring the plasmid pRI203, containing the Y. pseudotuberculosis invasion region, to antibiotics rifampicin, amikacin, ceftazidime and cefotaxime. These antibiotics, known to be excluded, to various degrees, by the bacterial outer membrane, resulted several-fold more active towards polycation-treated bacteria by comparison with controls. This increased permeability to antibiotics of E. coli HB 101 (pRI203) probably depends upon the binding of polycations to the acidic moieties of lipopolysaccharide, as already suggested for other gram-negative bacteria.
A series of 4-heterotricyclic substituted 1,4-dihydropyridines were prepared. The compounds were evaluated for inotropic, chronotropic and calcium antagonist properties. The tested compounds are fairly good as calcium antagonists, but exert potent selective bradycardic effects.
In thirteen patients, the repair of a soft tissue defect of the lower limb required a free tissue transfer revascularized by microvascular grafts. The indication of vascular grafting was either the absence of vessels or inadequate recipient vessels. Proximal anastomoses were performed on the femoral artery and the femoral vein or the long saphenous vein. All the transfers were done in one stage procedure. In two cases, a transitory arteriovenous shunt was established. Three flaps out of thirteen have been lost by thrombosis. The discussion concerns the causes of the failures and the indication of the establishment of a transitory or a temporary arterioveinous shunt prior to free flap transfer.
The o-, m- and p-acetoxymethyl-N,N,N-trimethylbenzenemethanaminium iodide (2a-c) as cyclovinilogues of acetylcholine are described. This structural modification allows to modulate the cholinergic activity of the natural neurotransmitter along the sequence: agonist----partial agonist----antagonist, which is referred to meta (2b), para (2c) and ortho (2a) regioisomers, respectively.
The authors report a new case of osteoid osteoma of the lunate. The absence of any specific clinical or radiographic features emphasises the importance of computed tomography, which not only confirms the diagnosis, but, more importantly, defines the topography and also guides the surgical approach and even the surgical technique.