Biomedical subjects

S Perri

Publications and source records attributed to S Perri.

At least 19 recordsLinked to original sources

PubMed2004

[Two cases of small bowel ischemia due to unusual cause].

The authors report 2 cases of small bowel ischemia due to unusual cause. In both cases, vasculopathy was the cause of ischemia, but with a different etiology. In the first case, a mesenteric inflammatory veno-occlusive disease, with striking features of extensive phlebitis and venulitis affecting the veins of the small intestine and mesentery, without arterial involvement of this district was observed and histological examination showed inflammatory lymphocytic infiltrates and myointimal hyperplasia of the veins. The second case affected by intestinal ischemia from secondary and multiple cholesterol embolism, the histological examination showed inflammatory infiltrates with (lymphocytes and granulocytes) in the vessels of submucosal mesenteric area, by loose intimal fibrosis incorporating cholesterol clefts. Both patients required surgical exploration with resection of ischemic bowel. In the second case laparoscopy was the initial approach which allowed to identify the extension of ischemia with special regard to the perforation. The ultimate diagnosis is possible only with histological examination. Clinically, patients show the general signs of intestinal ischemia with pain, vomiting and bloody diarrhea. Prognosis depends on the extension of the lesions and the early surgical treatment.

Aged↗

PubMed2003

[Intraoperative cholangiography during laparoscopic cholecystectomy: selective or routine?].

Since its presentation by Mirizzi in 1931, the role of intraoperative cholangiography (ICHO) has been controversial and has become an argument even more disputed with the introduction of laparoscopic cholecystectomy (VLC) in 1988. The Authors reviewed their experience to determine the most appropriate use of ICHO during VLC on the basis of a retrospective analysis of cases of selective ICHO. From December 1991 to January 2001, 597 patients, 552 elective procedure and 45 emergency procedure, were reviewed. Of 552 patients 62 presented with at least one diagnostic criterion for symptomatic gallstone disease and were treated by means of ERCP completed with endoscopic sphincterectomy (ES) when a stone of the common bile duct was found, while the remaining 490 patients underwent VLC; a total of 10 ICHO were performed, two of which in the ERCP group and 8 in the VLC group. The 45 patients treated in emergency underwent VLC; in 43 cases ICHO was performed. Of all patients, there were 2 cases of common bile duct injuries (0.33%) and in both cases ICHO was not performed. A cholangiogram added 27 min to the average duration of surgery. On the basis of both the literature and Authors' experience, it can be stated that the routine use of ICHO is not useful to reduce bile duct injuries, while it significantly increases the cost of the surgical procedure due to the increase of average operative time. The use of ICHO seems to be effective to demonstrate clinically unsuspected choledocholitiasis, although, at present, the real clinical advantage deriving from the detection of these stones is not clear. The Authors conclude that further prospective, randomized studies are necessary to assess the precise role of ICHO with regard to VLC.

Cholangiography↗

PubMed2001

Human immunodeficiency virus type 1 Gag-specific vaginal immunity and protection after local immunizations with sindbis virus-based replicon particles.

The majority of human immunodeficiency virus (HIV) infections occur through vaginal and rectal transmission. In seeking a safe, nonreplicating gene-delivery vector that can induce mucosal and systemic immune responses and protection, Sindbis virus-based replicon particles expressing HIV-1 Gag (SIN-Gag) were developed. In mice, after nasal or intramuscular immunization with SIN-Gag and vaginal challenge with vaccinia virus (VV) expressing HIV-1 Gag (VV-Gag), CD8(+) T cell-mediated responses were detected locally, in the vaginal mucosa and in the draining iliac lymph nodes (ILNs), and systemically, in the spleen. However, the mice were not protected against VV-Gag replication in the ovaries. In contrast, after vaginal or rectal immunization with SIN-Gag and vaginal challenge with VV-Gag, despite lower local CD8(+) T cell-mediated responses in the vaginal mucosa and ILNs, the mice were protected against VV-Gag replication in the ovaries. Therefore, local immunization with SIN-Gag induced both local mucosal cell-mediated responses and protection.

AIDS Vaccines↗

PubMed2001

[Laparoscopic appendicectomy: an 8-year clinical experience].

BACKGROUND: For more than a century, open appendectomy through a laparotomy has been the golden standard for the surgical removal of the appendix. Nowadays, many surgeons question the utility of laparoscopic surgery to perform appendectomies because it is commonly stated that the appendix can be removed through a small surgical incision carrying a minimal surgical trauma to the patient. Although open appendectomy is really safe, on the other hand it carries a considerable risk of postoperative complications, is associated with postoperative pain and affects patient s normal activity. Laparoscopic appendectomy was first described in 1983 and, in many studies, it is described to be better than open standard technique for the treatment of appendiceal diseases. The aim of the present study is the retrospective analysis of laparoscopic appendectomies performed in a 8-year period. METHODS: The authors report on 129 patients who underwent laparoscopic appendectomy. RESULTS: Conversion rate was 0.7 %, while the laparoscopic procedure was completed in 96 female and 32 male patients. The position of the appendix was behind the cecum in 37 cases, associate diseases were found in 15 cases. Mean operative time was 51 minutes; kind of laparoscopic instrumentation affected the operation time. Histologically there were 71 (55.5 %) focal appendicitis, 22 (17.1 %) suppurative appendicitis, 11 (8.6 %) gangrenous appendicitis, 18 (14.1 %) chronic appendicitis showing signs of previous suppurative episodes and 6 (4.7 %) normal appendix. There were neither in-hospital morbidity nor mortality. Follow-up showed reduced postoperative pain, short hospital stay, fast return to complete social activity. CONCLUSIONS: The authors conclude that laparoscopic technique can be considered a safe and effective procedure for the removal of the appendix as it has the advantage of allowing faster postoperative recovery; moreover the author recommend a wider and routinely use for appendectomy.

Adolescent↗

PubMed2001

[Efficacy of somatostatin and its analogues in the treatment of acute pancreatitis: clinical retrospective study].

Acute pancreatitis is an acute inflammatory disease of the pancreas, with variable involvement of other regional tissues or remote organ systems. Acute pancreatitis is mild in 80% of cases; virtually all patients with this form of disease will survive, because it's associated with minimal organ dysfunction and uneventful recovery; the severe pancreatitis develops in 20% of cases and is associated with higher morbidity and mortality. It's most important to identify the severity of disease at the moment of hospital admission; many scoring systems have been developed to serve as early prognostic signs: Ranson's criteria, Imrie's criteria, Apache II score, Balthazar's TC score. Recently, new drugs have been proposed in the treatment of acute pancreatitis, as, for example, calcitonine, glucagon, systemic antioxidants, antagonists of the receptors of interleukines, antiproteases (aprotinin and gabexate-mesilate) and the inhibitors of pancreatic secretions (somatostatin and its analogues). However, many controversies still exist concerning the real efficacy of these drugs in the treatment of acute pancreatitis, particularly regarding the inhibitors of pancreatic secretions: recently, some studies showed that somatostatin is able to actually reduce the local complication of the disease and the development of severe forms of acute pancreatitis; on the other hand, other studies failed to show real advantages of somatostatin reducing morbidity and mortality for pancreatitis. The aim of present study is a retrospective analysis of patients affected by acute pancreatitis in order to evaluate efficacy of somatostatin and its analogues. All patients subdivided in two groups: group A, patients treated with conventional therapy plus somatostatin and/or octreotide (SS/LS), and group B, patients treated only with conventional therapy. Results seem to show that somatostatin does not positively affect morbidity and mortality in patients with acute pancreatitis. The Authors conclude that, at present; somatostatin cannot be considered surely effective in preventing complications and mortality in acute pancreatitis. Further studies are still necessary to verify the effectiveness of somatostatin and its analogues in the therapy of acute pancreatitis.

Acute Disease↗

PubMed2001

[Total thyroidectomy in the surgical treatment of thyroid disease a retrospective clinical study].

BACKGROUND: Thyroid diseases constitute a group of benign and malignant affections, among which the most represented is multinodular goitre. Nowadays, an important question regards routine total thyroidectomy as the treatment of choice for all thyroid diseases. The aim of the present study is to verify if total thyroidectomy can always represent an option for modern surgery of thyroid disease. METHODS: One hundred-thirty-seven patients underwent operations for thyroid disease during an 11-year period. Fifty-three patients underwent total thyroidectomy, 27 affected by a benign pathology and 26 by a malignant one. RESULTS: Both short term and long term results have been analysed. CONCLUSIONS: In conclusion, the authors affirm that a complete resection of the gland is mandatory for the surgeon in the treatment of malignant diseases because the primary aim for oncologic surgery of the thyroid is the reduction of local recurrence and the increase of survival. As far as benign diseases are concerned, some surgeons affirm that morbility of non-total operations is lower than total thyroidectomy; anyway, the authors affirm that the most important factor to prevent morbility after total thyroidectomy is an appropriate surgical technique. In this way, both the identification of parathyroid glands and the identification preparation of recurrent nerve are considered the most valid method to prevent lesions. Another factor in favour of total thyroidectomy is represented by the risk of carcinoma on the residual tissue.

Adult↗

PubMed2000

Significance of duplex/colour Doppler sonography in hepatic arterial chemotherapy for patients with liver metastases from colorectal carcinoma.

AIMS: The aim of the study was to evaluate the importance of duplex/colour Doppler ultrasound in a protocol of hepatic regional chemotherapy, by measuring the blood flow in the hepatic artery, portal vein, hepatic veins, and inferior caval vein of patients with unresectable liver metastases from colorectal carcinoma. METHODS: Thirty-nine consecutive subjects were selected for this study, including 21 patients who had unresectable histologically confirmed liver metastases from colorectal carcinoma (Group A), and 18 asymptomatic volunteers as normal controls (Group B). All subjects of Groups A and B were examined using duplex/colour Doppler sonography. After the ultrasound study, all patients of Group A were submitted to the administration of high dose mitomycin C into the hepatic artery, with concomitant detoxication of post-hepatic venous blood. RESULTS: The mean value of the hepatic artery blood flow was significantly higher (P=0.0009) in liver metastases patients (361 ml/min, SEM=24 ml/min) than in normal controls (245 ml/min, SEM=20 ml/min). Also, the mean Doppler perfusion index was higher in liver metastases patients than in normal controls. For each patient of Group A, the total dose of mitomycin C to be infused was calculated based on the blood flow in the hepatic artery. In this way the concentration of mitomycin C in the hepatic artery was always greater than 3 microg/ml. The duration of detoxication was calculated based on the blood flow in the inferior caval vein. For two patients only, the blood flow was lower than 1000 ml/min, with the necessity to protract the duration of detoxication over 2 hours. CONCLUSIONS: The measurement of the blood flow in hepatic vessels of patients with liver metastases seems to be very important in establishing the total dose of drug which has to be infused in hepatic arterial chemotherapy, and to determine the duration of concomitant detoxication of post-hepatic venous blood.

Adult↗

PubMed2000

Replicon vectors derived from Sindbis virus and Semliki forest virus that establish persistent replication in host cells.

Alphavirus replicon vectors are well suited for applications where transient, high-level expression of a heterologous gene is required. Replicon vector expression in cells leads to inhibition of host macromolecular synthesis, culminating in eventual cell death by an apoptotic mechanism. For many applications, including gene expression studies in cultured cells, a longer duration of transgene expression without resulting cytopathic effects is useful. Recently, noncytopathic Sindbis virus (SIN) variants were isolated in BHK cells, and the mutations responsible were mapped to the protease domain of nonstructural protein 2 (nsP2). We report here the isolation of additional variants of both SIN and Semliki Forest virus (SFV) replicons encoding the neomycin resistance gene that can establish persistent replication in BHK cells. The SIN and SFV variant replicons resulted from previously undescribed mutations within one of three discrete regions of the nsP2 gene. Differences among the panel of variants were observed in processing of the nonstructural polyprotein and in the ratios of subgenomic to genomic RNAs. Importantly, high-level expression of a heterologous gene was retained with most replicons. Finally, in contrast to previous studies, efficient packaging was obtained with several of the variant replicons. This work expands the utility of noncytopathic replicons and the understanding of how alphavirus replicons establish persistent replication in cultured cells.

Genetic Vectors↗

PubMed2000

Infection of human dendritic cells by a sindbis virus replicon vector is determined by a single amino acid substitution in the E2 glycoprotein.

The ability to target antigen-presenting cells with vectors encoding desired antigens holds the promise of potent prophylactic and therapeutic vaccines for infectious diseases and cancer. Toward this goal, we derived variants of the prototype alphavirus, Sindbis virus (SIN), with differential abilities to infect human dendritic cells. Cloning and sequencing of the SIN variant genomes revealed that the genetic determinant for human dendritic cell (DC) tropism mapped to a single amino acid substitution at residue 160 of the envelope glycoprotein E2. Packaging of SIN replicon vectors with the E2 glycoprotein from a DC-tropic variant conferred a similar ability to efficiently infect immature human DC, whereupon those DC were observed to undergo rapid activation and maturation. The SIN replicon particles infected skin-resident mouse DC in vivo, which subsequently migrated to the draining lymph nodes and upregulated cell surface expression of major histocompatibility complex and costimulatory molecules. Furthermore, SIN replicon particles encoding human immunodeficiency virus type 1 p55(Gag) elicited robust Gag-specific T-cell responses in vitro and in vivo, demonstrating that infected DC maintained their ability to process and present replicon-encoded antigen. Interestingly, human and mouse DC were differentially infected by selected SIN variants, suggesting differences in receptor expression between human and murine DC. Taken together, these data illustrate the tremendous potential of using a directed approach in generating alphavirus vaccine vectors that target and activate antigen-presenting cells, resulting in robust antigen-specific immune responses.

Adenovirus E2 Proteins↗

PubMed2000

Alphavirus DNA and particle replicons for vaccines and gene therapy.

Alphaviruses have several features that make them attractive as gene delivery platforms, and vectors derived principally from Sindbis virus (SIN), Semliki Forest virus (SFV), and Venezuelan equine encephalitis virus (VEE), are currently being developed as prophylactic and therapeutic vaccines for infectious diseases and cancer. Alphavirus vectors, termed "replicons", retain the nonstructural protein genes encoding the viral replicase, that in turn programme high level cytoplasmic amplification of the vector RNA. We have developed plasmid DNA and recombinant vector particle delivery systems derived from the prototype alphavirus, SIN. Each system uses RNA polymerase II-based expression of alphavirus genome components and both vector formats are highly efficacious towards inducing robust antigen-specific immune responses in vaccinated animals. To increase the potency of SIN vector particles, which are not known to be lymphotropic, the tropism was re-directed for efficient infection of dendritic cells, both in vitro and in vivo.

Alphavirus↗

PubMed1999

Stable alphavirus packaging cell lines for Sindbis virus and Semliki Forest virus-derived vectors.

Alphavirus vectors are being developed for possible human vaccine and gene therapy applications. We have sought to advance this field by devising DNA-based vectors and approaches for the production of recombinant vector particles. In this work, we generated a panel of alphavirus vector packaging cell lines (PCLs). These cell lines were stably transformed with expression cassettes that constitutively produced RNA transcripts encoding the Sindbis virus structural proteins under the regulation of their native subgenomic RNA promoter. As such, translation of the structural proteins was highly inducible and was detected only after synthesis of an authentic subgenomic mRNA by the vector-encoded replicase proteins. Efficient production of biologically active vector particles occurred after introduction of Sindbis virus vectors into the PCLs. In one configuration, the capsid and envelope glycoproteins were separated into distinct cassettes, resulting in vector packaging levels of 10(7) infectious units/ml, but reducing the generation of contaminating replication-competent virus below the limit of detection. Vector particle seed stocks could be amplified after low multiplicity of infection of PCLs, again without generating replication-competent virus, suggesting utility for production of large-scale vector preparations. Furthermore, both Sindbis virus-based and Semliki Forest virus-based vectors could be packaged with similar efficiency, indicating the possibility of developing a single PCL for use with multiple alphavirus-derived vectors.

Alphavirus↗

PubMed1997

Effects of mutations within and adjacent to the terminal repeats of hepatitis B virus pregenomic RNA on viral DNA synthesis.

The viral polymerase and several cis-acting sequences are essential for hepadnaviral DNA replication, but additional host factors are likely to be involved in this process. We previously identified two sequences, UBS and DBS (upstream and downstream binding sites), present in multiple copies in and adjacent to the pregenomic RNA (pgRNA) terminal redundancy, that were specifically recognized by a 65-kDa host factor, p65. The possible roles of these two sequences in hepatitis B virus (HBV) replication were investigated in the context of the intact viral genome. UBS is contained within the terminal redundancy of pgRNA, and the 5' copy of this sequence is essential for viral replication. Mutations within the central core of UBS ablate p65 binding and selectively block synthesis of plus-strand DNA, without affecting RNA packaging or minus-strand synthesis. The DBS sequence, which is located downstream of the pgRNA polyadenylation site, overlaps the core (C) protein coding region. All mutations introduced into this site severely affected viral replication. However, these effects were shown to result from dominant negative effects of mutant core polypeptides rather than from cis-acting effects on RNA recognition. Thus, the 5' UBS but not DBS sites play important cis-acting roles in HBV DNA replication; however, the involvement of p65 in these roles remains a matter for investigation.

Cells, Cultured↗

PubMed1996

The plasmid RK2 initiation protein binds to the origin of replication as a monomer.

The TrfA protein encoded by the broad host range bacterial plasmid RK2 specifically binds to eight direct repeats (iterons) present at the plasmid replication origin to initiate DNA replication. Purified TrfA protein is largely in the form of a dimer, and using a dimerization test system that involves the fusion of the amino-terminal domain of the lambda cI repressor protein to TrfA, we show that the TrfA protein forms dimers in vivo. Because of the high stability of the dimer form of TrfA, the formation of heterodimers between the wild-type and different sized TrfA proteins requires in vivo de novo folding of the primary protein sequence or in vitro denaturation and renaturation. The results of gel mobility shift assays using in vitro or in vivo formed heterodimers indicated that the TrfA protein binds to the iteron DNA as a monomer. Furthermore, when the monomeric and dimeric forms of TrfA are separated by gel filtration chromatography, only the protein in the chromatographic position of the monomeric form demonstrated significant DNA binding activity. These results indicate that only the monomer form of the TrfA protein is active for binding to the iterons at the RK2 replication origin.

Bacterial Proteins↗

PubMed1996

A host factor that binds near the termini of hepatitis B virus pregenomic RNA.

The terminal regions of hepatitis B virus (HBV) pregenomic RNA (pgRNA) harbors sites governing many essential functions in the viral life cycle, including polyadenylation, translation, RNA encapsidation, and DNA synthesis. We have examined the binding of host proteins to a 170-nucleotide region from the 5' end of HBV pgRNA; a large portion of this region is duplicated at the 3' end of this terminally redundant RNA. By UV cross-linking labeled RNA to HepG2 cell extracts, we have identified a 65-kDa factor (p65) of nuclear origin which can specifically bind to this region. Two discrete binding sites were identified within this region; in vitro cross-competition experiments suggest that the same factor binds to both elements. One binding site (termed UBS) overlaps a portion of the highly conserved stem-loop structure (epsilon), while the other site (termed DBS) maps 35 nucleotides downstream of the hexanucleotide polyadenylation sequence. Both binding sites are highly pyrimidine rich and map to regions previously found to be important in the regulation of viral polyadenylation. However, functional analysis of mutant binding sites in vivo indicates that p65 is not involved in the polyadenylation of HBV pgRNA. Potential roles for the factor in viral replication in vivo are discussed.

Binding Sites↗

PubMed1995

[Inguinal hernioplasty: current trends].

The Authors report their experience in the surgical management of 282 inguinal hernias classified according to Gilbert's classification. The different techniques used were compared analysing the results obtained in 104 patients operated with the Bassini hernioplasty, while in 120 cases the Lichteinstein tension-free repair and in 58 cases the Shouldice hernioplasty were performed. In the patients operated according to the Lichteinstein tension-free technique an Autosuture mesh was used. The Authors conclude that the Lichteinstein tension-free repair is preferable, not simply for the incidence, although low in this series, of recurrence observed with the Bassini hernioplasty, but particularly for the reduced postoperative pain, the fast return to full activities, the low cost, and the possibility to be performed in Day-Hospital.

Adolescent↗

PubMed1994

Hepadnavirus reverse transcription initiates within the stem-loop of the RNA packaging signal and employs a novel strand transfer.

Replication of the hepadnavirus genome occurs by reverse transcription of an RNA pregenome and is mediated by the viral polymerase; the polymerase is also required for packaging of the pregenome through interaction with the RNA packaging signal, epsilon. Previous work suggested that reverse transcription of minus-strand DNA initiates within the sequence element DR1 (direct repeat 1) and that disruption of DR1 activates a cryptic initiation site in a downstream copy of epsilon. However, using active duck hepatitis B virus polymerase expressed in a yeast Ty vector system, we demonstrate that synthesis of minus-strand DNAs with 5' ends at DR1 requires the stem-loop of epsilon, whereas the production of DNAs mapping to epsilon does not require DR1. Mutations at epsilon that remove homology between epsilon and DR1 eliminate reverse transcripts with 5' ends in DR1, and restoring homology at DR1 to a mutant epsilon partially restores DNAs mapping to DR1. Insertions of one nucleotide into the bulge region of the epsilon stem-loop increase the length of minus-strand DNA whose 5' ends map to DR1 by one nucleotide. Thus, very short minus-strand primers are initiated within epsilon, rather than in DR1 as previously supposed; they are then transferred to a four-nucleotide homology in DR1. Transfer was also observed in vivo during replication of duck hepatitis B virus in avian cells; in this case, transfer is from the 5' copy of epsilon to the 3' copy of DR1. This minus-strand transfer reaction is likely to be a general feature of all hepadnaviruses.

Animals↗

PubMed1993

[Subclavian steal syndrome. Clinical aspects and therapeutic problems].

Cerebrovascular disease is a leading cause of morbidity and mortality in Italy. Although atherosclerotic involvement of the carotid artery is more prevalent, some patients suffer from stenosis of the subclavian artery, usually proximal to the origin of the vertebral artery. Neurological symptoms result from reversed flow in the vertebral artery, so-called "subclavian-steal". This collateral pathway may rob the posterior circulation of perfusion to the degree of producing episodes of vertebrobasilar insufficiency. The authors have therefore reviewed their experience with this disease and present their findings, therapeutic procedures and short-term results. During 1990 four patients affected by "subclavian-steal syndrome" were observed at the Surgical Department of Montecchio Maggiore Hospital (VI). Two patients were operated on and axillo-axillary bypass operations were performed (with a 5 mm Gore-tex graft). The goal of surgical treatment is to alleviate cerebrovascular symptomatology by restoring flow to the subclavian artery distal to the occlusion. Axillo-axillary bypass offers distinct advantages over the alternative methods such as transthoracic procedures or carotid-subclavian bypass. Axillo-axillary bypass is a technically simple procedure with very good results and minimal complications. It avoids sternotomy, thoracotomy and clavicular resections: the carotid artery is not involved in the procedure. The authors conclude that axillo-axillary bypass is a cheap, safe and effective treatment for symptomatic subclavian artery insufficiency.

Aged↗

PubMed1993

DNA sequence requirements for interaction of the RK2 replication initiation protein with plasmid origin repeats.

Replication of plasmid RK2 in a variety of Gram-negative bacteria requires its origin of replication and the plasmid-encoded TrfA proteins (TrfA-33 and TrfA-44). The initiation of replication requires that the TrfA proteins bind to a series of 17-base pair (bp) direct repeats located within the RK2 origin. The conserved 17-bp repeats are arranged in tandem and are separated by less conserved spacer sequences of 4-6 bp in length. A series of plasmids containing one or two iterons, with or without the less conserved spacer sequences, were constructed to analyze the DNA sequence requirements for binding of TrfA-33 to the iterons. In addition to the analysis of TrfA binding in vitro, the plasmid constructs were examined for their ability to exert incompatibility toward an RK2 replicon in Escherichia coli. These analyses revealed that the conserved 17-bp iteron sequence itself is not sufficient for TrfA binding; the adjacent less conserved spacer sequences are also required. Site-specific mutagenesis was carried out to determine the importance of specific bases within the spacer sequence for binding activity and a consensus sequence for a TrfA-specific binding unit was determined. DNase I and methylation interference footprinting procedures were also carried out to characterize the TrfA-binding unit complex. Finally, it was shown that the binding of the TrfA-33 protein to two adjacent TrfA binding units on a DNA fragment is not substantially affected by the relative orientation or spacing between the two units.

Bacterial Proteins↗