De novo malignancies following liver transplantation: results from a multicentric study in central and southern Italy, 1990-2008.

OBJECTIVE: The objective of this study was to quantify incidence rates (IR) and risks of de novo tumors (except nonmelanoma skin cancers) in patients who underwent orthotopic liver transplantation (OLT) in central and southern Italy. METHODS: Data were collected on 1675 patients (75.5% males) who underwent OLT in six Italian transplantation centers in central and southern Italy (1990-2008). The time at risk of cancer (person years [PY]) was computed from OLT to the date of cancer diagnosis, death, or last follow-up, whichever occurred first. The number of observed cancer cases were compared with the expected one using data from population-based cancer registries. We computed gender- and age-standardized incidence ratios (SIRs) and 95% confidence intervals (CIs). RESULTS: During 10,104.3 PYs (median follow-up, 5.2 years), 98 patients (5.9% of the total) were diagnosed with a de novo malignancy (for a total of 100 diagnoses). Twenty-two of these cancers were post-transplantation lymphoproliferative disorders (PTLD; 18 non-Hodgkin lymphoma [NHL] and 2 Hodgkin's lymphoma [HL]), 6 were Kaposi's sarcoma (KS), and 72 were solid tumors (19 head and neck [H&N], 13 lung, 11 colon-rectum, 6 bladder, and 4 melanoma). The overall incidence was 9.9 cases/10(3) PYs, with a 1.4-fold significantly increased SIR (95% CI, l.2-1.7). Significantly increased SIRs were observed for KS (37.3), PTLD (3.9), larynx (5.7), melanoma (3.1), tongue (7.1), and H&N (4.5) cancers. CONCLUSIONS: These results confirmed that OLT patients are at greater risk for cancer, mainly malignancies either virus-associated or related to pre-existent factors (eg, alcohols). These observations point to the need to improve cancer surveillance after OLT. The on-going enrollment of patients in the present cohort study will help to elucidate the burden of cancer after OLT and better identify risk factors associated with its development.

Primary and reactivated HHV8 infection and disease after liver transplantation: a prospective study.

Human herpesvirus 8 (HHV8) is pathogenic in humans, especially in cases of immunosuppression. We evaluated the risk of HHV8 transmission from liver donors, and its clinical impact in southern Italy, where its seroprevalence in the general population is reported to be as high as 18.3%. We tested 179 liver transplant recipients and their donors for HHV8 antibodies at the time of transplantation, and implemented in all recipients a 12-month posttransplant surveillance program for HHV8 infection. Of the 179 liver transplant recipients enrolled, 10.6% were HHV8 seropositive before transplantation, whereas the organ donor's seroprevalence was 4.4%. Eight seronegative patients received a liver from a seropositive donor, and four of them developed primary HHV8 infection. Two of these patients had lethal nonmalignant illness with systemic involvement and multiorgan failure. Among the 19 HHV8 seropositive recipients, two had viral reactivation after liver transplantation. In addition, an HHV8 seronegative recipient of a seronegative donor developed primary HHV8 infection and multicentric Castleman's disease. In conclusion, primary HHV8 infection transmitted from a seropositive donor to a seronegative liver transplant recipient can cause a severe nonmalignant illness associated with high mortality. Donor screening for HHV8 should be considered in geographic areas with a high prevalence of such infection.

Characterization of a triacylglycerol lipase that liberates arachidonic acid from bovine chromaffin cells during secretion.

Primary cultures of chromaffin cells from bovine adrenal medullae were used as a model to study lipolytic events during stimulus-secretion coupling. It has been shown that chromaffin cells liberate arachidonic acid in addition to their main secretion product, the catecholamines. To understand more about the mechanism of arachidonic acid liberation, chromaffin cells were labeled with radioactive arachidonic acid, stimulated, and then analyzed for changes in lipid composition. After stimulation with 10(-4) M acetylcholine, the radioactivity of triacylglycerols decreased to the same extent that the free arachidonic acid level rose. This finding suggests that in bovine chromaffin cells a stimulation-dependent triacylglycerol lipase (triacylglycerol hydrolase; EC 3.1.1.3) is involved in arachidonic acid liberation. Further work was performed on detection, characterization, and isolation of this enzyme. Triacylglycerol lipase activity was found in whole cell homogenates and in plasma membrane fractions isolated from adrenal medullary tissue. The plasma membrane lipase showed a pH optimum of 4.3. The apparent Michaelis constant was determined as 3.3 x 10(-4) mol/L. Ca2+ did not influence the enzymatic activity. To differentiate the plasma membrane triacylglycerol lipase from the previously described plasma membrane diacylglycerol lipase of chromaffin cells, the influence of RG 80267, a specific diacylglycerol lipase inhibitor, was examined. RG 80267 (50 microM) inhibited the triacylglycerol lipase by only 24%, although diacylglycerol lipase was totally inhibited with only 20 microM RG 80267. The pH optimum of homogenate lipase was broad, lying between 4 and 7. Starting from the soluble fraction of whole cell homogenates, the triacylglycerol lipase was partially purified by ultracentrifugation and size-exclusion chromatography.(ABSTRACT TRUNCATED AT 250 WORDS)

Arachidonic acid liberated by diacylglycerol lipase is essential for the release mechanism in chromaffin cells from bovine adrenal medulla.

Chromaffin cells from bovine adrenal medulla secrete catecholamines on stimulation with acetylcholine. In addition to the activation of the phosphatidylinositol cycle, arachidonic acid is generated, which was thought to be the result of phospholipase A2 activation. We have demonstrated in isolated plasma membranes of these cells that arachidonic acid is generated by a two-step reaction of diacylglycerol and monoacylglycerol lipase splitting diacylglycerol, which originates from the action of phospholipase C on phosphatidylinositols. No phospholipase A2 activity could be detected in plasma membranes so far. External addition of arachidonic acid increases the release in the absence and in the presence of agonist. Inhibition of the diacylglycerol lipase by RHC 80267 suppresses the catecholamine release, which is restored on addition of arachidonic acid. This effect, however, is reversed by lipoxygenase inhibitors, indicating that it is not arachidonic acid itself, but one of its lipoxygenase products, that is essential for inducing exocytosis.