Biomedical subjects

S Gagliardi

Publications and source records attributed to S Gagliardi.

At least 19 recordsLinked to original sources

PubMed2006

Use of porcine dermal collagen graft (Permacol) for hernia repair in contaminated fields.

BACKGROUND: Complicated hernias often involve contaminating surgical procedures in which the use of polypropylene meshes can be hazardous. Prostheses made of porcine dermal collagen (PDC) have recently been proposed as a means to offset the disadvantages of polypropylene meshes and have since been used in humans for hernia repairs. The aim of our study was to evaluate the safety and efficacy of incisional hernia repair using PDC as a mesh in complicated cases involving contamination. METHODS: A prospective study of hernia repair of complicated incisional hernias with contamination using PDC grafts was carried out at the Department of General, Emergency and Transplant Surgery of St Orsola-Malpighi University Hospital. RESULTS: From January 2004 up to the writing of this article, seven patients were treated for complicated incisional hernias with a PDC prosthesis. In six out of seven patients a bowel resection was carried out. There were not surgical complications. Morbidity was 14.2%. No recurrences and wound infections were observed. CONCLUSIONS: Incisional hernioplasty using PDC grafts is a potentially safe and efficient approach in complicated cases with contamination.

Abdominal Cavity↗

PubMed2005

On the difference in scattering behavior of cyclic and linear polymers in bulk.

It has been suggested that, due to topological constraints, rings in the melt may assume a more compact shape than Gaussian chains. In this paper, we exploit the availability of narrow fractions of perdeuterated linear and cyclic polydimethylsiloxane (PDMS) and, through the analysis of the small angle neutron scattering (SANS) profiles, demonstrate the difference in scattering properties of linear and cyclic PDMS molecules. As expected for Gaussian chains, for the H/D linear PDMS samples, log-log plots of the scattered intensity versus scattering vector Q display a Q((-2)) dependence. However, for H/D cyclic blends, the scaling exponent is higher than 2, as predicted by computer simulations reported in the literature. We show that cyclic molecules in bulk display the characteristic maximum in plots of scattered intensity versus Q((-2)) that is expected on the basis of Monte Carlo calculations and from the Casassa equation [E. F. Casassa, J. Polym. Sci. A 3, 605 (1965)]. It is also shown that, for rings, the Debye equation [P. Debye, J. Appl. Phys. 15, 338 (1944)] is no longer appropriate to describe the SANS profiles of H/D cyclic blends, at least up to M(w) approximately 10 000. For these samples, the Casassa form factor gives a better representation of the SANS data and we show that this function which was developed for monodisperse cyclics is still adequate to describe our slightly polydisperse samples. Deviations from all above observations are noted for M(w)>11 000 and are attributed to partial contamination of cyclic samples with linear chains. The failure of both the Debye and the Casassa form factors could be due to contamination of the cyclic fractions by linear polymers or to a real conformational change.

Journal Article↗

PubMed2004

Lichtenstein repair of inguinal hernia with Surgisis inguinal hernia matrix soft-tissue graft in immunodepressed patients.

While polypropylene mesh remains the preferred prosthesis material for hernioplasties, there are some problems with infections, intestinal obstruction and fistulization, and migration particularly in immunodepressed patients. A new degradable and reabsorbable material, the porcine small intestinal submucosa (Surgisis) has been developed for hernia repairs in humans. This prospective study evaluated the safety and efficacy of Lichtenstein hernioplasty using the Surgisis inguinal hernia matrix soft-tissue graft as a mesh in ten immunodepressed subjects. Six subjects were HIV-positive in the immunodepressive phase, and the other four had undergone transplantation (three kidney, one liver). There were no intraoperative or postoperative complications, recurrences, or wound infections. Thus Lichtenstein's hernioplasty using the Surgisis inguinal hernia matrix soft-tissue graft in immunodepressed patients promises safety and efficacy.

Absorbable Implants↗

PubMed2002

Selective inhibition of osteoclast vacuolar H(+)-ATPase.

The proton pump expressed on the plasma membrane of bone resorbing osteoclasts, and which mediates the acidification of the extracellular environment in resorption lacuna, belongs to the family of vacuolar H(+)-ATPases, which are enzymes ubiquitously distributed among all cells and are evolutionary conserved. These pumps have two functional domains: a peripherally associated cytoplasmatic section, and a proton channel composed of several subunits one of which, the 116 kDa subunit, is expressed exclusively in osteoclasts and confers unique functional and pharmacological properties to the osteoclast V-ATPase. It was demonstrated that inhibition of this pump can abolish bone resorption; therefore, osteoclast-selective inhibitors could provide novel and useful agents for the treatment of osteoporosis. This paper reviews the medicinal chemistry approaches that have allowed to obtain such new agents, most of which have been designed starting from the natural macrolide antibiotic bafilomycin A(1), a potent and selective inhibitor of all V-ATPases. Identification of SAR and of minimal structural requirements for bafilomycin activity have allowed to obtain (2Z,4E)-5-(5,6-dichloroindolyl)-2-methoxy-N-(1,2,2,6,6-pentamethylpiperidin-4-yl)-2,4-pentadienamide (SB-242784) which inhibits the osteoclastic proton pump and bone resorption in vitro. Although it inhibits the activity of non-osteoclastic proton pumps as well, it appears to have reasonable selectivity and its administration for 6 months prevented the loss of femoral and vertebral BMD in ovariectomized rats, without any significant renal effects in control and acid-loaded animals. Other independent approaches that did not start from bafilomycin have led to the discovery of a different class of V-ATPase inhibitors, among which 4-(2,6-dichlorobenzoyl)amino-2-trifluoromethyl(benzoimidazol-1-yl)acetyl morpholine (FR177995) was the most effective in preventing bone resorption in an ovariectomized rat model of osteoporosis. These compounds are of great pharmaceutical and medical interest because they allow to target a specific function of the osteoclast; however, only clinical trials might demonstrate whether they have significant advantages over other inhibitors of bone resorption for the treatment of osteoporosis.

Animals↗

PubMed2002

Use of prosthetic mesh in complicated incisional hernias.

BACKGROUND: Incisional hernia (IH) repair with conventional techniques is associated with high recurrence rate. Surgical repair using prosthetic biomaterials is becoming increasingly popular. On the basis of the good results an increasing number of surgeons have begun to use this technique. However prosthesis use in contaminated fields is still debated. In complicated IH contaminating surgical procedure are often performed and the use of meshes can be hazardous. The aim of this study was to report our experience about the treatment of complicated IH with prosthetic materials in an emergency surgery setting. METHODS: From November 1995 to November 2001 55 patients were submitted to emergency surgical treatment for complicated IH. Eleven patients were treated using a prosthetic device. Patients mean age was 71.3 (range 38-91). About 70% of patients had concomitant major cardiac or pulmonary diseases. RESULTS: Thirty-two IH were strangulated, 23 were incarcerated. In all patients a viscerolysis was carried out. In 6 patients a small bowel resection was done and in 4 subjects a large bowel resection was performed. Eight patients were submitted to omental resection. There were not differences in morbidity and mortality between the studied group. Recurrence rate was significantly lower in prosthetic treated group. CONCLUSIONS: We concluded that prosthetic repair of complicated IH is feasible in selected cases allowing abdominal wall anatomy re-establishment.

Adult↗

PubMed2001

Stepwise modulation of neurokinin-3 and neurokinin-2 receptor affinity and selectivity in quinoline tachykinin receptor antagonists.

A stepwise chemical modification from human neurokinin-3 receptor (hNK-3R)-selective antagonists to potent and combined hNK-3R and hNK-2R antagonists using the same 2-phenylquinoline template is described. Docking studies with 3-D models of the hNK-3 and hNK-2 receptors were used to drive the chemical design and speed up the identification of potent and combined antagonsits at both receptors. (S)-(+)-N-(1-Cyclohexylethyl)-3-[(4-morpholin-4-yl)piperidin-1-yl]methyl-2-phenylquinoline-4-carboxamide (compound 25, SB-400238: hNK-3R binding affinity, K(i) = 0.8 nM; hNK-2R binding affinity, K(i) = 0.8 nM) emerged as the best example in this approach. Further studies led to the identification of (S)-(+)-N-(1,2,2-trimethylpropyl)-3-[(4-piperidin-1-yl)piperidin-1-yl]methyl-2-phenylquinoline-4-carboxamide (compound 28, SB-414240: hNK-3R binding affinity, K(i) = 193 nM; hNK-2R binding affinity, K(i) = 1.0 nM) as the first hNK-2R-selective antagonist belonging to the 2-phenylquinoline chemical class. Since some members of this chemical series showed a significant binding affinity for the human mu-opioid receptor (hMOR), docking studies were also conducted on a 3-D model of the hMOR, resulting in the identification of a viable chemical strategy to avoid any significant micro-opioid component. Compounds 25 and 28 are therefore suitable pharmacological tools in the tachykinin area to elucidate further the pathophysiological role of NK-3 and NK-2 receptors and the therapeutic potential of selective NK-2 (28) or combined NK-3 and NK-2 (25) receptor antagonists.

Amino Acid Sequence↗

PubMed2001

Discovery of a novel antitumor benzolactone enamide class that selectively inhibits mammalian vacuolar-type (H+)-atpases.

A series of naturally occurring compounds reported recently by multiple laboratories defines a new small-molecule class sharing a unique benzolactone enamide core structure and diverse biological actions, including inhibition of growth of tumor cells and oncogene-transformed cell lines. Here we show that representative members of this class, including salicylihalamide A, lobatamides A-F, and oximidines I and II inhibit mammalian vacuolar-type (H+)-ATPases (V-ATPases) with unprecedented selectivity. Data derived from the NCI 60-cell antitumor screen critically predicted the V-ATPase molecular target, while specific biochemical assays provided confirmation and further illumination. The compounds potently blocked representative V-ATPases from human kidney, liver, and osteoclastic giant-cell tumor of bone but were essentially inactive against V-ATPases of Neurospora crassa and Saccharomyces cerevisiae and other membrane ATPases. Essential regulation of pH in cytoplasmic, intraorganellar, and local extracellular spaces is provided by V-ATPases, which are ubiquitously distributed among eukaryotic cells and tissues. The most potent and selective V-ATPase inhibitors heretofore known were the bafilomycins and concanamycins, which do not discriminate between mammalian and nonmammalian V-ATPases. Numerous physiological processes are mediated by V-ATPases, and aberrant V-ATPase functions are implicated in many different human diseases. Previous efforts to develop therapeutic pharmacological modulators of V-ATPases have been frustrated by a lack of synthetically tractable and biologically selective leads. Therefore, availability of the unique benzolactone enamide inhibitor class may enable further elucidation of functional and architectural features of mammalian versus nonmammalian V-ATPase isoforms and provide new opportunities for targeting V-ATPase-mediated processes implicated in diverse pathophysiological phenomena, including cancer.

Animals↗

PubMed2000

A sensitive method to assay the xanthine oxidase activity in primary cultures of cerebellar granule cells.

Since xanthine oxidase (XO, Xanthine:oxidoreductase, E.C.1.2.3.22) is a key enzyme in reactive oxygen specie formation which plays a major role in cell oxidative stress, the availability of a sensitive and simple assay useful to detect its activity in monolayer cell cultures is worthwhile. In order to achieve this, we developed a method in which the conversion of pterine into isoxanthopterin is monitored fluorimetrically. Temperature assay was 50 degrees C. The activity of XO was detected in cerebellar granule cells exposed to glutamate. Since XO is formed from protease-dependent xanthine dehydrogenase processing, its activity appearance was found to be prevented by the protease inhibitor, leupeptin, as well as the glutamate NMDA-receptor inhibitor, MK-801, and the Ca(++) complexing agent, EGTA. The reported novel protocol, at variance with a conventional method, is shown to be a simple, fast, sensitive and relatively cheap method to assay XO activity. In addition, the reported assay can be applied to any cell type in culture.

Animals↗

PubMed1999

Replacement of the quinoline system in 2-phenyl-4-quinolinecarboxamide NK-3 receptor antagonists.

Results from a medicinal chemistry approach aimed at replacing the quinoline ring system in the potent and selective human neurokinin-3 (hNK-3) receptor antagonists 1-4 of general formula I are discussed. The data give further insight upon the potential NK-3 pharmacophore. In particular, it is highlighted that both the benzene-condensed ring and the quinoline nitrogen are crucial determinants for optimal binding affinity to the hNK-3 receptor. Some novel compounds maintained part of the binding affinity to the receptor (5, 6, 10 and 13) and compound 5, featuring the naphthalene ring system, appears to be suitable for further modifications; it offers the option to introduce electron-withdrawing groups at position 2 and 4, conferring on the ring an overall electron-deficiency similar to that of the quinoline.

Animals↗

PubMed1999

Selective inhibitors of the osteoclast vacuolar proton ATPase as novel bone antiresorptive agents.

The proton ATPase located on the apical membrane of the osteoclast is essential to the bone resorption process. This proton pump is, therefore, an attractive molecular target for the design of novel inhibitors of bone resorption, and potentially useful for the treatment of osteoporosis and related metabolic diseases of bone. Recently, several inhibitors with different degrees of selectivity for the osteoclast V-ATPase have been reported. In particular, systematic chemical modifications of the macrolide antibiotic bafilomycin A1 have identified the minimal structural requirements for activity and allowed the design of simplified analogues that demonstrate high potency and selectivity for the osteoclast enzyme.

Journal Article↗

PubMed1999

Glutamate neurotoxicity in rat cerebellar granule cells involves cytochrome c release from mitochondria and mitochondrial shuttle impairment.

To gain some insight into the mechanism by which glutamate neurotoxicity takes place in cerebellar granule cells, two steps of glucose oxidation were investigated: the electron flow via respiratory chain from certain substrates to oxygen and the transfer of extramitochondrial reducing equivalents via the mitochondrial shuttles. However, cytochrome c release from intact mitochondria was found to occur in glutamate-treated cells as detected photometrically in the supernatant of the cell homogenate suspension. As a result of cytochrome c release, an increase of the oxidation of externally added NADH was found, probably occurring via the NADH-b5 oxidoreductase of the outer mitochondrial membrane. When the two mitochondrial shuttles glycerol 3-phosphate/dihydroxyacetone phosphate and malate/oxaloacetate, devoted to oxidizing externally added NADH, were reconstructed, both were found to be impaired under glutamate neurotoxicity. Consistent early activation in two NADH oxidizing mechanisms, i.e., lactate production and plasma membrane NADH oxidoreductase activity, was found in glutamate-treated cells. In spite of this, the increase in the cell NADH fluorescence was found to be time-dependent, an index of the progressive damage of the cell.

Animals↗

PubMed1999

Chemistry and structure activity relationships of bafilomycin A1, a potent and selective inhibitor of the vacuolar H+-ATPase.

Bafilomycin A1, a macrolide antibiotic isolated from the fermentation of Streptomyces spp., is a potent and selective inhibitor of vacuolar-type proton translocating ATP-ases (V-ATPases) and was used to study the physiological role of this class of enzymes. An extensive chemical effort on the unusual structure of this macrolide led to the synthesis of significantly different bafilomycin derivatives. None of the new analogues was more potent than the parent compound but provided a significant amount of information about the structural requirements for the inhibitory activity of bafilomycin A1 in particular on chicken osteoclast (cOc) ATPase. The vinylic methoxy group adjacent to a carbonyl function, the dienic system and the hydroxy group at position 7 were recognized to be essential features for bafilomycin V-ATPase-inhibitory activity. This information was utilized to design simplified novel derivatives as inhibitors of bone resorption.

Animals↗

PubMed1998

(2Z,4E)-5-(5,6-dichloro-2-indolyl)-2-methoxy-N-(1,2,2,6,6- pentamethylpiperidin-4-yl)-2,4-pentadienamide, a novel, potent and selective inhibitor of the osteoclast V-ATPase.

Optimisation of a novel series of osteoclast ATPase inhibitors led to (2Z,4E)-5-(5,6-dichloro-2-indolyl)-2-methoxy-N-(1,2,2,6,6- pentamethylpiperidin-4-yl)-2,4-pentadienamide (1) that was the most potent compound in an in vitro osteoclast ATPase assay and in human bone resorption assays. Two of the possible geometric isomers have also been prepared and shown to be significantly less potent than 1.

Enzyme Inhibitors↗

PubMed1998

Evaluation of the cone biopsy excisor compared with the large loop for electrosurgical excision of cervical lesions.

Data incorporated from August 1994 to July 30, 1997.Objective: To compare a newly designed triangular electrode, the Cone Biopsy Excisor to the loop electrode with respect to the margin evaluation, fragmentation, and thermal damage of the conization specimen.Methods: After approval by the Institutional Review Boards of Hartford Hospital, St. Francis Hospital, and New Britain General Hospital/University of Connecticut, patients were randomly assigned to undergo conization with the Cone Biopsy Excisor or with the large loop. Inclusion criteria included biopsy proven CIN II, CIN III, inadequate colposcopy, positive endocervical curettage, or cytohistological discrepancy. Exclusion criteria included pregnancy, undiagnosed uterine bleeding, and invasive carcinoma. The procedures were performed by senior residents on clinic patients at the respective institutions. In addition, after FDA approval November 18, 1996, private OB/GYN practitioners performed cases and added those results to the study. Seventy-eight patients were randomized to the Cone Biopsy Excisor, while 77 patients were randomized to the loop electrosurgical excision procedure (LEEP). To obtain the surgical specimen, Force 2 Valley Lab generators were used with wattage ranging from 35 to 50 according to the size of the instrument chosen, 40/60 blend of coagulation, and cutting current.Pathology reports were reviewed to determine the amount of fragmentation that occurred during the procedure and for tissue diagnosis. Specimens were then evaluated by two gynecologic pathologists blinded to the instrument used. The specimens were analyzed for the ability to evaluate the margins and for degree of thermal damage. A thermal damage score was assigned to each specimen. The scoring system results in 4 levels of thermal damage, from one (minimal thermal damage) to four (heavy thermal damage). Follow-up data was obtained from the patients' medical and pathology records.Results: Seventy-two of 78 (92%) Cone Biopsy Excisor cases vs 10 of 77 (13%) LEEP cases submitted one specimen to pathology, P <.001 based on a chi(2) test. Mean number of specimens submitted to pathology per case in the Cone Biopsy Excisor group was 1.1 +/- 0.5 vs 2.2 +/- 0.8 in the LEEP group, P <.001 based on a t test. Margins were unable to be interpreted because of thermal damage in 2 of 78 (3%) in the Cone Biopsy Excisor group vs 14 of 77 (18%) in the LEEP group, P <.003 based on a chi(2) test.Conclusion: The Cone Biopsy Excisor provided a cervical specimen that had less fragmentation and less thermal damage with margins that were less likely to be indeterminate than those obtained with the large loop electrosurgical procedure.

Journal Article↗

PubMed1998

Synthesis and structure-activity relationships of bafilomycin A1 derivatives as inhibitors of vacuolar H+-ATPase.

The macrolide antibiotic bafilomycin A1 is a highly potent and selective inhibitor of all the vacuolar ATPases (V-ATPases). With the aim of obtaining novel analogues specific for the osteoclast subclass of vacuolar ATPase, 31 derivatives of bafilomycin A1 were synthesized and tested for their ability to inhibit differentially the V-ATPase-driven proton transport in membrane vesicles derived from chicken osteoclasts (cOc) and bovine chromaffin granules (bCG). Although none of the new analogues were more potent than the parent compound, the obtained data provided a significant amount of information about the structural requirements for the inhibitory activity of bafilomycin A1. The different effects of a few analogues on the two enzymes could also suggest the possibility of a selective modulation of the V-ATPases in different tissues.

Adenosine Triphosphate↗

PubMed1998

5-(5,6-Dichloro-2-indolyl)-2-methoxy-2,4-pentadienamides: novel and selective inhibitors of the vacuolar H+-ATPase of osteoclasts with bone antiresorptive activity.

The vacuolar H+-ATPase (V-ATPase), located on the ruffled border of the osteoclast, is a proton pump which is responsible for secreting the massive amounts of protons that are required for the bone resorption process. With the aim to identify new agents which are able to prevent the excessive bone resorption associated with osteoporosis, we have designed a novel class of potent and selective inhibitors of the osteoclast proton pump, starting from the structure of the specific V-ATPase inhibitor bafilomycin A1. Compounds 3a-d potently inhibited the V-ATPase in chicken osteoclast membranes (IC50 = 60-180 nM) and were able to prevent bone resorption by human osteoclasts in vitro at low-nanomolar concentrations. Notably, the EC50 of compound 3c in this assay was 45-fold lower than the concentration required for half-maximal inhibition of the V-ATPase from human kidney cortex. These results support the validity of the osteoclast proton pump as a useful molecular target to produce novel inhibitors of bone resorption, potentially useful as antiosteporotic agents.

Animals↗

PubMed1998

Neuronal apoptosis in rats is accompanied by rapid impairment of cellular respiration and is prevented by scavengers of reactive oxygen species.

Apoptosis of cerebellar granule cells induced by potassium withdrawal is accompanied by a very rapid decrease in both cell and mitochondrial respiration supported by glucose and succinate, respectively. The respiratory control ratio, which is an index of oxidative phosphorylation and therefore reflects the ability of mitochondria to produce ATP, is reduced by 50% within the first 2 h after the beginning of apoptosis, insulin-like growth factor I (IGF-I), actinomicin D or cycloheximide, previously reported to inhibit apoptosis, fully prevent the impairment of cellular respiration while scavengers of reactive oxygen species partially inhibit apoptosis and restore cellular respiration.

Animals↗

PubMed1998

Fumarate permeation in normal and acidotic rat kidney mitochondria: fumarate/malate and fumarate/aspartate translocators.

In order to gain some insight into the fate of fumarate synthesised in the cytosol in the purine nucleotide cycle and in amino acid catabolism, the capability of both rat kidney mitochondria and acidotic rat kidney mitochondria to take up either externally synthesised, via adenylsuccinate lyase, or added fumarate in exchange with intramitochondrial malate or aspartate was tested by means of both spectrophotometric and isotopic techniques. The appearance of either malate or aspartate caused by the presence of fumarate was revealed outside normal and acidotic mitochondria by using specific substrate detecting systems. Consistently, externally added fumarate was found to cause efflux of either [14C]-malate or [14C]-aspartate from loaded mitochondria. The occurrence in rat kidney mitochondria of two separate translocators, i.e., fumarate/malate and fumarate/aspartate carriers, is shown in the light of saturation kinetics and the different inhibitor sensitivity. The fumarate/aspartate antiporters found in normal and acidotic mitochondria appear to differ from each other.

Acidosis↗