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Biomedical subjects

L Pieri

Publications and source records attributed to L Pieri.

At least 19 recordsLinked to original sources
PubMed2004

Evolution of endotoxin-induced lung injury in the rat beyond the acute phase.

OBJECTIVES: Intratracheal endotoxin in rats causes acute lung injury. Here we have addressed the cellular physiopathology of lung recovery from that injury. METHODS: The lungs of 5 untreated rats and rats treated with intratracheal endotoxin from 2, 3, 5, 8 (5 rats each) and 15 days (2 rats) were studied by light and electron microscopy and immunohistochemistry. RESULTS: In the acute phase there was a reduction in the aerated spaces (p < 0.01); diffuse infiltration of granulocytes and macrophages; hyperplasia of type-II pneumocytes, and hypertrophy of interstitial cells. Aerated spaces improved during recovery. In the early recovery phase (3-8 days) the compartmentalization of infiltrating cells varied significantly (p < 0.01): macrophages remained widespread while neutrophils were inside blood vessels. Many pneumocytes were intermediate between type-I and type-II cells. In the late recovery phase (15 days) the infiltrate disappeared; myofibroblasts were significantly more than previously (p < 0.01) and extracellular matrix was abundant; type-II pneumocytes contained non-lamellated lipid inclusions. CONCLUSIONS: Macrophages play a pivotal role in the damage-repair processes of the lung following endotoxin injury, leading to an increase in extracellular matrix, differentiation of myofibroblasts and altered secretion of surfactant by newly differentiated type-II pneumocytes.

Animals↗
PubMed2004

Endogenous oxidative stress induces distinct redox forms of tumor necrosis factor receptor-1 in melanoma cells.

Receptors of the TNFR superfamily possess abundant thiols in their extracellular domains, which makes them susceptible to redox modulation by prooxidant agents and processes. Previous studies from our laboratory have documented that membrane gamma-glutamyltransferase (GGT) activity can originate reactive oxygen species in the extracellular milieu, during the GGT-mediated metabolism of extracellular glutathione. The present study was aimed thus to verify a possible redox-modulating effect of GGT activity on TNFR1 receptors. The thiol-specific probe maleimide-polyethylene glycol was used to selectively label the reduced thiol groups in proteins of cell lysates; fractions corresponding to TNFR1 were then identified by immunoblot. In human melanoma Me665/2 cells, expressing varying GGT levels, at least five distinct forms of TNFR1 have been thus identified. The more oxidized forms appear to be prevalent in the 2/60 clone, expressing higher GGT levels, as compared to clone 2/21. Stimulation of GGT activity in the latter induced an increase of the oxidized TNFR1 forms. It is conceivable that different redox states of TNFR1 may correspond to different binding affinity and/or changes in the transducing function of the receptor. As GGT is frequently expressed by malignant tumors, the described phenomena might concur to alter the sensitivity of cancer cells to agents targeted on activation of TNF-alpha-dependent signaling pathways.

Cell Line, Tumor↗
PubMed2002

Use of periodate-lysine-paraformaldehyde for the fixation of multiple antigens in human skin biopsies.

Periodate-lysine-paraformaldehyde (PLP) has been proposed as a fixative for glycoprotein antigens which should stabilize periodate oxidized polysaccharide chains through lysine mediated crosslinks, either directly or by the intermediation of formaldehyde. In spite of premises and attempts reported in the literature, this fixative has never become popular for the study of membrane antigens of immune system cells, which leads to doubts on its real efficacy. We have addressed this issue in biopsies of human skin and found that PLP followed by cryoprotection with 30% sucrose and cryosectioning, or PLP fixation of isolated epidermal sheets, consistently provided for good preservation of morphology and intense labeling of major histocompatibility complex class II molecules, CD 1 a, CD4, CD8, E-cadherin, cytokeratins in general, cytokeratin-18 in particular, and bromodeoxyuridine, incorporated by cycling cells in vitro, and for the demonstration of tyrosinase enzyme activity. PLP-fixed, osmicated and epon-embedded epidermal sheets proved as good as sheets fixed with a mixture of formaldehyde and glutaraldehyde for electron microscopic morphological analysis. Also, these sheets were amenable to immunoperoxidase staining of Langerhans cell membrane antigen CD1a and keratinocyte membrane antigen E-cadherin before being osmicated and prepared for electron microscopy. In a parallel paper, we had also shown that oral mucosa biopsies fixed in PLP showed good morphology and immunolabeling of CD54, CD80, CD83 and CD86. Therefore, we conclude that PLP can be proposed as a multi-task fixative for light and electron microscopic analysis of membrane, cytoplasmic and nuclear antigens of immune system cells and keratinocytes.

Acetone↗
PubMed2000

Membrane gamma-glutamyl transpeptidase activity of melanoma cells: effects on cellular H(2)O(2) production, cell surface protein thiol oxidation and NF-kappa B activation status.

The metabolism of glutathione by membrane-bound &ggr;-glutamyl transpeptidase (GGT) has been recently recognized as a basal source of hydrogen peroxide in the extracellular space. Significant levels of GGT activity are expressed by malignant tumours, and in melanoma cell lines they were found to correlate with the malignant behaviour. As hydrogen peroxide and other oxidants can affect signal transduction pathways at several levels, the present study was aimed to verify: (i) the occurrence of GGT-dependent production of hydrogen peroxide in melanoma cells; (ii) the effects of GGT-dependent prooxidant reactions on known redox-sensitive cellular targets, i.e. protein thiols, the nuclear transcription factor NF-kappa B and p53. Two melanoma Me665/2 cell clones, exhibiting traces of (clone 2/21) or high (clone 2/60) GGT activity, were studied. The occurrence of GGT-dependent production of hydrogen peroxide was apparent in 2/60 cells, in which it was accompanied by lower levels of cell surface protein thiols. In 2/60 cells, GGT expression was also associated with higher levels of NF-kappa B activation, as compared to GGT-poor 2/21 cell clone. Indeed, stimulation or inhibition of GGT activity in 2/60 cells resulted in progressive activation or inactivation of NF-kappa B, respectively. An analysis of the p53 gene product indicated lack of protein expression in 2/60 cells, whereas a mutant protein was highly expressed in 2/21 cells. Taken together, these results indicate that the expression of GGT activity can provide melanoma cells with an additional source of hydrogen peroxide, and that such prooxidant reactions are capable to modify protein thiols at the cell surface level. In addition, GGT expression results in an up-regulation of the transcription factor NF-kappa B, which could explain the higher metastatic behaviour reported for GGT-rich melanoma cells as compared to their GGT-poor counterparts.

Blotting, Western↗
PubMed1999

Hodgkin's lymphoma: an isolated case of involvement of the ureter.

We report the case of a man in which a Hodgkin's lymphoma involved the ureter as the very first clinical situs of the disease. Ureteral involvement in lymphomas is very rare (0.86%-7% and 1%-16%, found in two studies, respectively, of cases of patients with lymphoma examined post mortem) and when it does occur it is secondary to renal involvement or retroperitoneal adenopathies. It is by all means exceptional as an isolated situs of disease. Those cases reported in the literature as presenting lymphomatous involvement of the ureter have always been diagnosed as Non-Hodgkin's lymphomas.

Combined Modality Therapy↗
PubMed1998

Is laparoscopic sonography a reliable and sensitive procedure for staging colorectal cancer? A comparative study.

BACKGROUND: Laparoscopic colectomy has developed rapidly with the explosion of technology. In most cases, laparoscopic resection is performed for colorectal cancer. Intraoperative staging during laparoscopic procedure is limited. Laparoscopic ultrasonography (LUS) represents the only real alternative to manual palpation during laparoscopic surgery. METHODS: We evaluated the diagnostic accuracy of LUS in comparison with preoperative staging and laparoscopy in 33 patients with colorectal cancer. Preoperative staging included abdominal US, CT, and endoscopic US (for rectal cancer). Laparoscopy and LUS were performed in all cases. Pre- and intraoperative staging were related to definitive histology. Staging was done according to the TNM classification. RESULTS: LUS obtained good results in the evaluation of hepatic metastases, with a sensitivity of 100% versus 62.5% and 75% by preoperative diagnostic means and laparoscopy, respectively. Nodal metastases were diagnosed with a sensitivity of 94% versus 18% with preoperative staging and 6% with laparoscopy, but the method had a low specificity (53%). The therapeutic program was changed thanks to laparoscopy and LUS in 11 cases (33%). In four cases (12%), the planned therapeutic approach was changed after LUS alone. CONCLUSIONS: The results obtained in this study demonstrate that LUS is an accurate and highly sensitive procedure in staging colorectal cancer, providing a useful and reliable diagnostic tool complementary to laparoscopy.

Biopsy↗
PubMed1998

Sarmazenil-precipitated withdrawal: a reliable method for assessing dependence liability of benzodiazepine receptor ligands.

The benzodiazepine receptor partial inverse agonist sarmazenil exhibits in vivo proconvulsive, but not convulsant, effects in different paradigms in rodents. Intravenous sarmazenil challenge given at several fixed intervals following the termination of repeated treatment with a markedly sedative dose of diazepam in squirrel monkeys was effective in precipitating withdrawal signs, but had no comparable effects in vehicle-treated controls. The precipitated withdrawal reaction was not only robust, but it was consistently observed in all of the diazepam-treated monkeys. Thus, the use of sarmazenil challenge in the precipitated withdrawal paradigm provides a reliable method for assessing the development of physical dependence during repeated treatment with benzodiazepine receptor agonists.

Animals↗
PubMed1997

[Urotheliomas of the upper urinary tract. The role of computed tomography in integrated diagnostic imaging].

INTRODUCTION: Transitional cell carcinomas are frequent in the bladder but rare in the renal pelvis. Most upper urinary tract cancers are suspected and detected with urography and retrograde pyelography; CT is important in the questionable cases at US, urography and retrograde pyelography, but it is also useful to detect locoregional disease. We report the findings of 35 patients, with ureteral lesions to assess the role of CT in the diagnosis and staging. MATERIALS AND METHODS: Thirty-five patients were examined with US and CT; 27 underwent urography, 16 retrograde pyelography and 4 nephrostomic pyelography, CT staging was made with Hahn's criteria related to TNM (stages CT I, CT II, CT III). All patients underwent surgery and the histologic findings were compared with CT staging. RESULTS: CT detected all lesions and characterized them from a morphological viewpoint (intraluminal minus, wall thickening). Using Hahn's CT staging we obtained agreement with histologic findings in 21 of 23 cases in CT stage I, six of 10 in CT stage II and 4 of 5 in CT stage III. CONCLUSIONS: CT is an important tool for both diagnosis and therapy because it shows the renal cavities and parenchyma and permits accurate staging, differentiating the tumors localized in the wall from those with local spread or distant metastases. In our experience, CT is not useful to differentiate mucosal from pelvic-ureteral muscle invasion but peripelvic and periureteral fat invasion can be suspected when the infiltrated wall exhibits an irregular and spiculated profile.

Adult↗
PubMed1996

Interlaboratory reproducibility in reporting inadequate cervical smears--a multicentre multinational study.

A set of 300 vaginal smears was interpreted by 13 cytologists from six European laboratories, who were requested to report inadequate and suboptimal smears. The set had been appropriately seeded to reach approximately 10% inadequate and 20% suboptimal smear frequency. According to the majority report, 230 smears were classified as adequate (76.7%), 43 as inadequate (14.3%), and 27 as suboptimal (9.0%). Agreement with the majority report ranged from 52% to 91% (average 78%). Kappa statistics for reporting inadequate smears showed a high level of agreement for five cytologists, and fair to good agreement for eight. In contrast, kappa statistics for reporting suboptimal smears showed fair to good agreement with the majority report only in five instances, whereas agreement was poor for eight cytologists. 'Inadequate smear' rates may be used to compare the quality of smears received in different laboratories, as there is a high level of agreement among cytologists as to what constitutes an inadequate smear. However, this is not true for "suboptimal smear" rates, and more precise reporting criteria must be defined and tested if an intermediate category is to be retained to report poor quality smears: more precise reporting criteria must be defined and tested if an intermediate category is to be retained to report poor quality smears.

Europe↗
PubMed1995

Sarcoidosis: single bulky mesenteric lymph node mimicking a lymphoma.

A previously healthy man presented with acute abdominal pain that extended from the left lumbar area to the left iliac fossa and to the omolateral testicular region. Abdominal ultrasonography and CT scan showed a bulky mesenteric mass and mesenteric, paraaortic, and paracaval lymph nodes. Biopsy specimens of the mass revealed non caseating granulomas. Chest CT scan and 67Gallium thoracic scan demonstrated lymph node and parenchymal pulmonary involvement. Bronchoalveolar lavage (BAL) confirmed the presence of a low intensity alveolitis. Serum angiotensin converting enzyme (SACE) level was elevated. Two years after steroid therapy, markers of disease activity and abdominal ultrasonography are in the normal range.

Adult↗
PubMed1995

Laparoscopic sonography in screening metastases from gastrointestinal cancer: comparative accuracy with traditional procedures.

The wide use of operative and diagnostic laparoscopy has led to a greater use of the laparoscopic ultrasound (LUS) as a complementary procedure. A preliminary study was performed to evaluate the efficacy of LUS using a linear array laparoscopic probe characterized by double frequency, mechanical flexibility, and availability of Doppler analysis. LUS was performed in 36 patients with gastrointestinal neoplasms and compared with preoperative sonography, computed tomography, and with laparoscopy alone. LUS identified liver metastases with a sensitivity of 100% versus 60% for preoperative diagnostic means and laparoscopy. Nodal metastases were identified with a sensitivity of 96.1% and a specificity of 66.6%. Therapeutic planning was modified as result of LUS in 8 of 35 cases (22.9%). In patients with abdominal malignancy, LUS improves staging (cancer spread, nodal metastases, liver metastases), modifying therapeutic decisions. LUS represents a complementary, indispensable diagnostic method during laparoscopic surgery.

Bile Duct Neoplasms↗
PubMed1994

[Imaging diagnosis in pseudomembranous colitis].

Pseudomembranous colitis (PC) is a dangerous inflammatory disease which arises as a complication of systemic antibiotic therapy. The colon is the preferred localization of PC, which is caused by the alteration in the bacterial population of the bowel which favors the growth and activation of several germ types--e.g., the Clostridium difficile, whose toxins can damage the colonic mucosa deeply. Later, the condition may affect extramucosal structures thus causing an actual parietal alteration. Clinically, PC patients present with diarrhea, abdominal pain, onset or worsening of fever, impairement of the main body functions. The colonic mucosa appears macroscopically edematous and is covered with yellowish plaques, called "pseudomembranes", which adhere strictly to the mucosa. Pseudomembranes are made by fibrin, mucus, leucocytes and epithelial remnants. The diagnosis is made on the basis of laboratory tests--i.e. the demonstration of Clostridium difficile or its toxins in the feces. Endoscopy is the examination of choice when PC is suspected because it can demonstrate the typical mucosal alterations directly. In this paper the main etiologic, pathologic and clinical features of PC are presented and the role of diagnostic imaging examinations is discussed, not only in demonstrating the typical lesions but also in the spatial evaluation of the condition and in its follow-up.

Colon↗
PubMed1994

[The National Workshop on Defecography: anorectal deformities with a functional origin (prolapse, intussusception, rectocele)].

The nonoperative treatment--i.e., rubber band ligation and sclerotherapy--of mucous rectal prolapse, rectocele and intussusception is much less expensive than conventional surgery (Lit. 325,000 vs. 6,500,000, p < 0.0001 on the average). Symptom relief, however, has been reported in 0 to 57% of cases only, according to current literature. A possible cause is represented by improper management from misdiagnosis, relying on clinical findings only, overestimating mucous prolapse in 36.37% of cases and underestimating intussusception in 14.22% of cases (with respect to defecography). Defecography is a cost-effective method (average cost: Lit. 37,000) potentially reducing failure rate after the surgical repair of rectal prolapse.

Ambulatory Surgical Procedures↗