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Biomedical subjects

M Gavioli

Publications and source records attributed to M Gavioli.

18 recordsLinked to original sources
PubMed2001

Endorectal sonographic appearances of rectal MALT lymphoma, its response to therapy, and local recurrence.

Endorectal sonography may significantly help to evaluate rectal lymphoma. We report the sonographic findings in a case of rectal non-Hodgkin's MALT (mucosa-associated lymphoid tissue) lymphoma, including the monitoring of response to therapy and confirmation of recurrence, in a 45-year-old man. On endorectal sonography of the rectal wall, the mucosa was markedly thickened to 1.1 cm and was diffusely hypoechoic and risen into multiple polypoid folds. The submucosa and muscularis propria appeared normal. Multiple lymph nodes were visualized in the perirectal fat; they were homogeneously hypoechoic, were round or oval, and ranged from 1.0 cm to 2.6 cm. Endoscopic biopsies revealed a grade I non-Hodgkin's MALT lymphoma. Following chemotherapy, endorectal sonography showed that the surface of the rectal mucosa had a smoother appearance and near-normal thickness, but lymph nodes, although smaller, remained visible in the perirectal fat. Four months later, endorectal sonography demonstrated a local relapse of disease, with significant thickening of the rectal mucosa and multiple lymph nodes visible in the perirectal fat. Following high-dose chemotherapy for the recurrence, endorectal sonography demonstrated a near-normal appearance of the rectal mucosa.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Crystallization and preliminary crystallographic study of the periplasmic domain of the Escherichia coli TolR protein.

The TolR protein from Escherichia coli is part of the Tol-Pal multiprotein complex used by group A colicins to penetrate and kill cells. All genes of the Tol-Pal system are conserved in Gram-negative bacteria and this system is thought to play a role in the maintenance of the bacterial envelope integrity, although its exact function is not known. The TolR protein comprises 142 amino acids. The periplasmic domain of the TolR protein has been expressed, purified and crystallized. The crystals belong to the tetragonal space group P4(1)22, with unit-cell parameters a = 46.3, c = 178.0 A. There are one or two molecules in the asymmetric unit. Frozen crystals diffract to at least 3.2 A resolution using synchrotron radiation. Selenomethionine-substituted periplasmic TolR protein is currently being produced in order to use multiwavelength anomalous dispersion (MAD) for phasing.

Bacterial Proteins↗
PubMed2000

Usefulness of endorectal ultrasound after preoperative radiotherapy in rectal cancer: comparison between sonographic and histopathologic changes.

PURPOSE: Our aim was to assess the advantages of endorectal ultrasound after preoperative radiotherapy in rectal cancer, its reliability in tumoral staging, and its capacity to identify completely sterilized lesions. METHODS: From 1994 to 1997, 29 patients with rectal cancer were systematically subjected to endorectal ultrasound before and after preoperative radiotherapy. Each patient was administered 30 to 50 Gy, followed by surgery six to eight weeks after completion of radiotherapy. Endorectal ultrasound was performed using a biplanar (linear and sectorial) endorectal probe. The morphologic, quantitative, and echo-pattern changes of the irradiated tumor were examined. Results of ultrasound findings before and after radiotherapy and a histologic examination of the surgical specimens were compared. Histopathologic studies were used to evaluate macromicroscopical radiation-induced changes, case by case. A comparison between tumoral shrinkage and fibrotic replacement was made using the semiquantitative Dworak's method. RESULTS: Morphologically and quantitatively, postradiation endorectal ultrasound showed the reappearance of anatomic cleavage planes, a considerable shrinkage of the tumor, and in low rectal tumors, an increase in the distance from the anorectal ring in more than 50 percent of the cases. These data had a direct influence on surgical treatment. Histologic examination showed that, in 28 out of 29 cases, fibrosis was the most dominant component of the irradiated lesions, varying by more than 50 to 100 percent of the lesion (four cases pTO). A comparison of postradiation endorectal ultrasound with histopathology revealed that fibrosis became the morphologic basis of ultrasound images; therefore, after radiotherapy, what endorectal ultrasound staged was no longer the tumor but the extent of fibrosis in the rectal wall. A histopathologic examination showed that the residual tumor, when present, was always within the fibrosis, never outside or separate from it. Postradiation endorectal ultrasound showed echo-pattern changes. Some of the changes (more echogenic and nonhomogeneous lesions) were histologically related to the persistence of the tumor to a considerable degree; other changes (reappearance of parietal layers) were related to complete sterilization of lesions in two of three cases. CONCLUSIONS: From the morphologic and quantitative point of view, postradiation endorectal ultrasound provides oncologists and surgeons useful information to assess treatment effectiveness and plan the surgical approach. From the tumor staging point of view, our report presents a completely new concept: that six to eight weeks after radiotherapy, endorectal ultrasound no longer stages the tumor, but rather the fibrosis that takes its place. However, postradiation endorectal ultrasound is a valid tool, because the extent of fibrosis in the rectal wall is a direct indication of the depth of residual cancer. A residual tumor, when present, is always inside the fibrosis. Finally, however, as regards the capacity of endorectal ultrasound to exclude or indicate complete sterilization of the lesion, the actual significance of the echo-pattern changes we observed needs to be assessed further by studies on a large number of cases.

Endosonography↗
PubMed2000

Proton motive force drives the interaction of the inner membrane TolA and outer membrane pal proteins in Escherichia coli.

The Tol-Pal system of the Escherichia coli envelope is formed from the inner membrane TolQ, TolR and TolA proteins, the periplasmic TolB protein and the outer membrane Pal lipoprotein. Any defect in the Tol-Pal proteins or in the major lipoprotein (Lpp) results in the loss of outer membrane integrity giving hypersensitivity to drugs and detergents, periplasmic leakage and outer membrane vesicle formation. We found that multicopy plasmid overproduction of TolA was able to complement the membrane defects of an lpp strain but not those of a pal strain. This result indicated that overproduced TolA has an envelope-stabilizing effect when Pal is present. We demonstrate that Pal and TolA formed a complex using in vivo cross-linking and immunoprecipitation experiments. These results, together with in vitro experiments with purified Pal and TolA derivatives, allowed us to show that Pal interacts with the TolA C-terminal domain. We also demonstrate using protonophore, K+ carrier valinomycin, nigericin, arsenate and fermentative conditions that the proton motive force was coupled to this interaction.

Bacterial Outer Membrane Proteins↗
PubMed1998

Escherichia coli tol-pal mutants form outer membrane vesicles.

Mutations in the tol-pal genes induce pleiotropic effects such as release of periplasmic proteins into the extracellular medium and hypersensitivity to drugs and detergents. Other outer membrane defective strains such as tolC, lpp, and rfa mutations are also altered in their outer membrane permeability. In this study, electron microscopy and Western blot analyses were used to show that strains with mutations in each of the tol-pal genes formed outer membrane vesicles after growth in standard liquid or solid media. This phenotype was not observed in tolC and rfaD cells in the same conditions. A tolA deletion in three different Escherichia coli strains was shown to lead to elevated amounts of vesicles. These results, together with plasmid complementation experiments, indicated that the formation of vesicles resulted from the defect of any of the Tol-Pal proteins. The vesicles contained outer membrane trimeric porins correctly exposed at the cell surface. Pal outer membrane lipoprotein was also immunodetected in the vesicle fraction of tol strains. The results are discussed in view of the role of the Tol-Pal transenvelope proteins in maintaining outer membrane integrity by contributing to target or integrate newly synthesized components of this structure.

Bacterial Outer Membrane Proteins↗
PubMed1997

[Preoperative radiotherapy in cancer of the rectum. Our 5-year experience].

Since 1990, 41 patients with rectal carcinoma have been submitted to preoperative radiotherapy, which induced a shrinkage of the tumor, favouring its surgical resection. Besides, in 3 cases the operative specimens were tumor free, and a higher incidence of A and B 1 categories was found. Surgical results have been compared with an analogous group of 20 patients, where surgery was performed as a first procedure, then followed by radiotherapy in 9. No increase of postoperative complications was observed. While analysis of follow-up results demonstrates a decrease of tumour recurrence in patients with preoperative radiotherapy, no difference in survival was registered, because of the development of extra-pelvic metastases.

Adult↗
PubMed1996

TolA central domain interacts with Escherichia coli porins.

TolA is an inner membrane protein with three domains: a transmembrane N-terminus and periplasmic central and C-terminal domains. The interaction of TolA with outer membrane porins of Escherichia coli was investigated. Western blot analyses of cell extracts with anti-TolA antibodies indicated that TolA forms high molecular weight complexes specifically with trimeric OmpF, OmpC, PhoE and LamB, but not with OmpA. The interaction of purified TolA domains with purified porins was also studied. TolA interacted with OmpF, PhoE and LamB porins via its central domain, but not with either their denatured monomeric forms or OmpA. Moreover, the presence or absence of lipopolysaccharides associated with trimeric porins did not modify the interactions. These results suggest that the specific interaction of TolA with outer membrane porins might be relevant to the function of Tol proteins.

Amino Acid Sequence↗
PubMed1996

[A rare case of primary abdominal actinomycosis].

The authors describe a case of primary abdominal actinomycosis operated on because of peritonitis sustained by a tubo-ovarian abscess. They discuss the pathogenesis of the case: the patient had been on intrauterine device contraception till two months earlier and had been operated on for breast cancer. Preoperative diagnosis is quite impossible and only the microscopic observation of the specimen can show the causative agent. Surgical options are reported, stressing the need for an adequate period of antimicrobial therapy.

Abscess↗
PubMed1996

[Prosthesis and emergency surgery of hernia].

Use of prostheses in emergency surgery is a controversial issue due to the risk of infection. We report our experience with a series of 31 strangled hernias treated in emergency situations with a polypropylene (n = 29) or a vinyl (n = 2) sheath placed in a pre-peritoneal or retro-muscular position. There were three small bowel resections and 13 resections of the omentum for necrosis. There were no cases of infectious complications during the post-operative period. There were no recurrent hernias during the follow-up. The absence of any supplementary morbidity after emergency prosthesis is in agreement with the data in the literature. These results suggest that a prosthesis can be proposed for strangled hernias when the weakness of the parietal wall would compromise a conventional procedure. Excluded are cases with severe infection, including peritonitis by gangrenous perforation of an incarcerated loop and associated colonic resections.

Emergency Medicine↗
PubMed1995

[Effect of menstrual cycle on the immune response to surgical stress].

The Authors have studied the effects of different surgical interventions on some factors of humoral and cell-mediated immuno-competence: 112 premenopausal women, operated on mainly for benign conditions, have been considered in order to evaluate the influence of various phases of menstrual cycle on surgical immunosuppression. Two schemes were used to stratify the study sample: in the first analysis, we have subdivided the patients in 59 cases in perimenstrual phase (0 through 6 and 21 through 36 days from last menstrual period, LMP) and 53 in periovulatory (7-20 days from LMP). The second stratification relied on the hormone-dependent phases determined by the putative time of ovulation 14 days after LMP: 51 cases in follicular phase and 61 cases in luteal phase have been considered. Immune parameters have been evaluated before surgery and the day after intervention. The first comparison stresses the worst outcome of immune parameters in patients operated on in the perimenstrual period (CD4, activated lymphocytes and C3 have significantly reduced post-operatively). The second part of the study shows no significant difference in the two groups as to such parametres.

Adolescent↗
PubMed1990

[Progress in the evaluation of lymphatic involvement in cancer of the rectum: endoscopic rectal lymphoscintigraphy].

The preoperative evaluation of lymphatic spread in rectal cancer constitutes a considerable problem. A prospective study including 45 patients operated for rectal cancer, was carried out in order to assess the diagnostic value of a new technique: endoscopic rectal lymphoscintigraphy. The results of the preoperative assessment were compared with histological data according to Dukes' classification (Dukes A/B: 22 cases, Dukes C: 23 cases). Analysis of these results revealed the sensitivity (80%), specificity (73%) and accuracy (80%) of this new technique. If, combined with endorectal ultrasonography, rectal lymphoscintigraphy might play highly significant role in identifying the indications for local excisions of small tumours; similarly, the effect of preoperative radiotherapy might be more thoroughly assessed.

Adenocarcinoma, Mucinous↗
PubMed1988

[Acute pulmonary edema due to hyperperfusion: experimental observations in the dog].

A condition of acute pulmonary edema was obtained experimentally in the dog, perfusing the lower lobe of the left lung by a roller pump with compatible canine plasma. The edema develops contemporarily to the increase of pressure in the pulmonary artery and the interstitial tissue: it diffuses principally in the interstitial tissue, while after clamping the pulmonary veins it is observed also inside the alveoli.

Acute Disease↗
PubMedDate not supplied

[Isolated jejunal rupture after closed thoraco-abdominal trauma].

INTRODUCTION: Short bowel disruption following blunt abdominal trauma is rare and hard to diagnose and to treat. Death rate depends both on timing of surgical procedure and on associated lesions. MATERIAL AND METHODS: We show a case of short bowel isolated lesion following fall from mountain bike, III degree in O.I.S. Classification. Abdominopelvic US and helicoidal CT scan were performed, reveling pneumoperitonaeum due to hollow viscus disruption. Surgical procedure was performed within five hours from trauma. RESULTS: No complications occurred in postoperative period. Upper alimentary tract X-ray proved a regular transit, without any fistula. Patient was discharged on 13th day. CONCLUSION: Laparotomy must not be delayed if there is any doubt about bowel conditions: it's demonstrated that timing of surgical procedure is related to prognosis. If haemodynamic status of the patient allows, careful abdomen CT evaluation is mandatory; adequate nutritional support in postoperative period is also very important.

Accidental Falls↗
PubMedDate not supplied

[Primary transitional-cell carcinoma of the male anterior urethra].

Primary carcinomas of the male anterior urethra account for less than 1% of all urological carcinoma. The majority of these neoplasias develop of the posterior part of the urethra (proximal portion). The most common histotype is the squamous-cellular carcinoma. We have only found 4 other published reports of primary transitional carcinoma of the male anterior urethra. The paper discusses the diagnostic and therapeutic procedures employed in these rare cases.

Aged↗