Francesca Mangili

Proliferation index of nonfunctioning pituitary adenomas: Correlations with clinical characteristics and long-term follow-up results

OBJECTIVEThe recurrence of nonfunctioning pituitary adenomas (NFPAs) after surgical removal is common. The aim of our study was to investigate and correlate the growth fraction of NFPAs with clinical characteristics and long-term follow-up results. METHODSTumor specimens were obtained from 101 consecutive patients with NFPAs (48 female patients and 53 male patients; mean age, 52.0 ± 1.5 yr). Specimens were immediately fixed in 10% buffered formalin and then embedded in paraffin. The Ki-67 antigen was assessed by immunocytochemical analysis using the monoclonal antibody MIB-1. The Ki-67 antigen labeling index (LI) was determined by counting a total of at least 1000 neoplastic nuclei. RESULTSThe mean Ki-67 LI for the 101 patients was 2.4 ± 0.3% (range, 0–23.0%). Only age at surgery was inversely correlated with the Ki-67 LI; sex, maximal tumor diameter, and invasiveness into the cavernous sinuses did not significantly affect the Ki-67 LI. The mean follow-up period was 39.7 ± 2.1 months. During follow-up monitoring, 23 patients experienced tumor recurrence, after a mean period of 28.6 ± 4.8 months. Invasiveness of the tumor on preoperative magnetic resonance imaging scans was the strongest predictor of late tumor recurrence, followed by previous pituitary surgery, younger age, and lack of postoperative radiotherapy. The Ki-67 LI had no independent prognostic value. CONCLUSIONOur study suggests that the clinical characteristics of patients with NFPAs, except for age at surgery, are not correlated with the Ki-67 LI. Moreover, the Ki-67 LI does not seem to provide independent information to identify patients at high risk for tumor recurrence.

Integrin-dependent induction of functional urokinase receptors in primary T lymphocytes.

In order to reach the sites of inflammation, lymphocytes leave the bloodstream and migrate into peripheral tissues, in a process involving integrin-mediated adhesion to the vascular endothelium, followed by transmigration across the endothelial barrier and through the underlying interstitial matrix. We have investigated the role of the plasminogen activator/plasmin system in normal T cell migration. Receptors for urokinase plasminogen activator (uPAR) were not expressed in resting T lymphocytes, but could be efficiently induced at the mRNA and protein level by coclustering of the antigen receptor complex and beta1 or beta2 integrins, through a signalling pathway involving both protein kinase C activation and an increase in intracellular cyclic AMP. Catalytic activation of plasminogen by uPAR-expressing T cells promoted their migration through an extracellular matrix in vitro. Plasmin-induced invasion was inhibited by plasmin-and urokinase inhibitors and by anti-uPAR antibodies. Finally, cytofluorimetric and immunohistochemical analysis of primary human tumor specimens showed the presence of uPAR positive infiltrating T cells in vivo. Collectively, these findings suggest that plasminogen activation may play a role in lymphocyte migration in vivo, and that integrin-dependent expression of membrane-associated endopeptidases could represent an additional step in the regulated process of leukocyte transmigration.

Determination of the proliferation and apoptotic index in adrenocorticotropin-secreting pituitary tumors: Comparison between micro- and macroadenomas

We investigated the growth fraction and cell loss fraction in a large group of patients with Cushings disease subdivided according to tumor size. Fifty-one patients, 8 males and 43 females, aged 12 through 61 years (mean age 34.6 +/- 1.5 years), were studied. Thirty-six patients had a microadenoma and the remaining 15 a macroadenoma. Immunohistochemical analysis was performed on paraffin-embedded material using a monoclonal antibody (MIB-1) directed against a proliferation-associated nuclear antigen, Ki-67, to measure the growth fraction. Apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method, using a monoclonal antibody recognizing areas of DNA fragmentation. Ki-67 labeling index and apoptosis were counted on separate slides in at least 1000 evaluable cells. Patients with a macroadenoma had a significantly higher value of Ki-67 index (9.3 +/- 2.7%) than patients with microadenoma (2.8 +/- 0.5%; P < 0.002), whereas the apoptotic index was not significantly different in the two groups (1.7 +/- 0.8% in macroadenomas versus 0.8 +/- 0.3% in microadenomas). Our study shows that ACTH-secreting macroadenomas are characterized by a higher cell growth fraction than microadenomas, whereas the cell loss fraction is not different. A high proliferation rate seems to play a major role in determining the progression from small to large pituitary tumors in Cushings disease.

In vivo evaluation of timing, degree, and distribution of bacterial translocation following experimental small bowel transplantation

These studies were designed to evaluate the correlation between morphologic and functional changes after heterotopic auxiliary small bowel isograft with systemic venous drainage and two ostomies in 20 Lewis rats. Morphologic damage of the graft was scored by full-thickness biopsies before surgery and 1, 3, 5, and 7 days after transplant. Functional evaluation of the graft was done, at the same time points, by urinary excretion of lactulose and mannitol injected in the proximal ostomy. The intestinal permeability was also studied by injecting Escherichia coli labeled with indium-111 oxine in the proximal ostomy. Translocation of radiolabeled bacteria was quantitated in extraintestinal tissues by radionuclide counts and number of viable organisms and in vivo by scinti-graphic imaging. One day after transplant, significant graft damage (score 17.2±4.2) was observed when compared with the pretransplant value (7.3±2.6). The degree of tissue injury was similar on days 3 (15.8±3.5) and 5 (16.1 ±3.9) after transplant and remained high on day 7 (11.8±2.8). The lactulose to mannitol ratio showed a significantly increased permeability on day 1 (17.5) versus pretransplant values (2.6), remained high on day 3 (8.6), and returned to normal values on day 5 (2.8). Translocation of bacteria to distant organs, as measured by both radionuclide counts and number of viable organisms, was strikingly enhanced on day 1 after transplantation, compared with control animals, but returned to the pretransplant value on day 3. A good qualitative and quantitative correlation was observed between radionuclide counts in the extraintestinal organs and in vivo images obtained by scintigraphic scanning. In conclusion, in this model, timing and degree of bacterial translocation do not seem to correlate well, with the exception of the acute posttransplantation phase, with morphologic and perme ability changes of the graft. Evaluation of translocation by scintigraphic imaging appears a suitable approach to study in vivo the kinetics and distribution of this process.

Mycobacterium tuberculosis Chaperonin 10 Is Secreted in the Macrophage Phagosome: Is Secretion Due to Dissociation and Adoption of a Partially Helical Structure at the Membrane?

To confirm that Mycobacterium tuberculosis chaperonin 10 (Cpn10) is secreted outside the live bacillus, infected macrophages were examined by electron microscopy. This revealed that the mycobacterial protein accumulates both in the wall of the bacterium and in the matrix of the phagosomes in which ingested mycobacteria survive within infected macrophages. To understand the structural implications underlying this secretion, a structural study of M. tuberculosis Cpn10 was performed under conditions that are generally believed to mimic the membrane environment. It was found that in buffer-organic solvent mixtures, the mycobacterial protein forms two main species, namely, a partially helical monomer that prevails in dilute solutions at room temperature and a dimer that folds into a beta-sheet-dominated structure and prevails in either concentrated protein solutions at room temperature or in dilute solutions at low temperature. A partially helical monomer was also found and was completely associated with negatively charged detergents in a micelle-bound state. Remarkably, zwitterionic lipids had no effect on the protein structure. By using N- and C-truncated forms of the protein, the C- and N-terminal sequences were identified as possessing an amphiphilic helical character and as selectively associating with acidic detergent micelles. When the study was extended to other chaperonins, it was found that human Cpn10 is also monomeric and partially helical in dilute organic solvent-buffer mixtures. In contrast, Escherichia coli Cpn10 is mostly dimeric and predominately beta-sheet in both dilute and concentrated solutions. Interestingly, human Cpn10 also crosses biological membranes, whereas the E. coli homologue is strictly cytosolic. These results suggest that dissociation to partially helical monomers and interaction with acidic lipids may be two important steps in the mechanism of secretion of M. tuberculosis Cpn10 to the external environment.

Avidin-biotin system in radioimmunoguided surgery for colorectal cancer. Advantages and limits.

PURPOSE: Radiolabeled monoclonal antibodies (MAbs) have been reported to allow tumor intraoperative detection by means of a gamma-detecting probe. The technology is called the Radioimmunoguided Surgery (RIGS®) system. The main inconveniences of the method are 1) the long interval needed for clearance of unattached MAbs from the patients body, between the injection of the MAb and surgery, and 2) the low sensitivity of current MAbs used in detecting small tumors. We describe a new method to overcome these inconveniences using biotinylated MAbs and avidin in order to obtain a rapid blood clearance of the radiolabeled MAbs both anticarcinoembryonic antigen and antitumor-associated glycoprotein-72 MAbs. METHODS: Twenty patients with primary and recurrent colorectal cancer have been enrolled in the study;125I-biotinylated MAbs FO23C5 (anticarcinoembryonic antigen) and B72.3 (antitumor-associated glycoprotein-72) followed by cold avidin were injected in 13 patients and 7 patients, respectively. RESULTS: A decrease of 94±3 perceNt of circulating radioactivity was Achieved in 3 to 5 days. PatientS underwent surgery approximAtely seven days after MAb injections rather than afder four weeks. Tumors were localized in 14/20 (70 pErcent) Patients (true positive), 2 (10 percent) were false Negative, and 4 (20 percent) were true negative. The overall sensitivity level in early-stage primary cancers was 37 percent when related to the presencE of disease and 75 percent when related to antigenic exprescion. The sensitivity for moRe advanced cancer and for recurRences was 10 percent. MoreOver, thein vivotumor dargeting of biotinylated MAb was demonstrated in frozen tumor section by direct streptoavidin-peroxidasE staining. CONCLUSIONS: The avidin-biotin system may enhance applicability and effectiveness of radioimMunoguided surgery (RIGS®).

Prognostic effect of DNA content depends on the amount of the residual disease in ovarian tumours

SummaryA retrospective study was conducted on 47 patients with ovarian malignancies (1986–1991). DNA content analysis, surgical stage, residual tumor and histological grade were correlated to prognosis. In our experience, 36 months survival rate shows a more favourable outcome in diploid forms 166·7%), compared with 34·5% in aneuploid ovarian cancer patients. The results of flow cytometry may be used in conjunction with other prognostic factors. such as stage, residual tumor after primary surgery, grade and histological type, to tailor treatment protocols based on risk assessment. The importance of RT after primary debulking surgery is emphasised in our study. In fact RT was the only independent prognostic factor. The magnitude of the prognostic effect of DNA ploidy is dependent on the ability of the surgeon to reach an optimal debulking surgery.

Bleeding Gastric Polyposis-Like Metastases of Hepatocellular Carcinoma

The first case ever described of symptomatic gastric polypoid metastases in a 62-year-old patient, who had undergone right hepatectomy for hepatocellular carcinoma (HCC) 2 years before, is reported. The patient presented recurrences of gastrointestinal bleeding. Barium meal and endoscopy showed multiple gastric polyps extending from the cardia to the pylorus. Histological examination of biopsies of these polyps resulted consistent with metastases of HCC. A total gastrectomy was performed for palliation of symptoms. Histopathological examination confirmed the presence of metastatic HCC: neoplastic nests implanted in the submucosa and extending towards the mucosa. The above observation supports that the possible route of spread in our patient could be hematogenous from reversed portal blood flow. The patient died 20 months after surgery, with liver recurrence of the tumor.