[Adrenomedullin. A new peptide involved in the regulation of the cardiovascular system]

Adrenomedullin was originally discovered in human pheochromocytoma but is now known to be widely distributed in various organs. Adrenomedullin is a potent vasodilatator peptide that exerts major effects on cardiovascular function. Plasma adrenomedullin concentration is increased in patients with cardiovascular disease such as hypertension, congestive heart failure, myocardial infarction, renal failure and other diseases. The present review summarizes the recent advances on adrenomedullin research and demonstrates that adrenomedullin is one of the important vasoactive peptides involved in the physiology and pathophysiology of cardiovascular system.

Biotechnologies and acute hepatic failure

Orthotopic liver transplantation survival for patients with acute liver failure is poor (50%). Mortality on the waiting list is high due to the lack of donors. For these reasons, the possibility of sustaining hepatic function by extra-corporeal liver perfusion must be considered. In this experimental research, two groups of pigs have been submitted to total de-vascularisation of the liver causing acute hepatic failure. In the first group (4 pigs) no extra-corporeal assistance has been used after total de-vascularisation. All pigs died between 16 and 33 hours after the acute hepatic failure was induced. In the second group (8 pigs) after complete hepatic de-vascularisation an extra-corporeal hepatic support by continuous allo-perfusion of isolated liver was performed using the Abouna-Costa extra-corporeal circuit. All pigs were observed during the acute hepatic failure which lasted from 6.30 to 7.30 hours. The data that were more positively influenced by the extra-corporeal assistance were ammonia and lactates that improved after the application of hepatic assistance.

A conventional beagle dog model for acute and chronic infection with Helicobacter pylori

Helicobacter pylori has been widely recognized as an important human pathogen responsible for chronic gastritis, peptic ulcers, gastric cancer, and mucosa-associated lymphoid tissue (MALT) lymphoma. Little is known about the natural history of this infection since patients are usually recognized as having the infection only after years or decades of chronic disease. Several animal models of H. pylori infection, including those with different species of rodents, nonhuman primates, and germ-free animals, have been developed. Here we describe a new animal model in which the clinical, pathological, microbiological, and immunological aspects of human acute and chronic infection are mimicked and which allows us to monitor these aspects of infection within the same individuals. Conventional Beagle dogs were infected orally with a mouse-adapted strain of H. pylori and monitored for up to 24 weeks. Acute infection caused vomiting and diarrhea. The acute phase was followed by polymorphonuclear cell infiltration, interleukin 8 induction, mononuclear cell recruitment, and the appearance of a specific antibody response against H. pylori. The chronic phase was characterized by gastritis, epithelial alterations, superficial erosions, and the appearance of the typical macroscopic follicles that in humans are considered possible precursors of MALT lymphoma. In conclusion, infection in this model mimics closely human infection and allows us to study those phases that cannot be studied in humans. This new model can be a unique tool for learning more about the disease and for developing strategies for treatment and prevention.

Laminin receptors in differentiated thyroid tumors: restricted expression of the 67-kilodalton laminin receptor in follicular carcinoma cells

The expression of integrin laminin receptors was investigated in normal thyroid primary cultures; immortalized normal thyroid cells (TAD-2); papillary (NPA), follicular (WRO), and anaplastic (ARO) thyroid tumor cell lines; seven thyroid tumors (four papillary and three follicular carcinomas); and normal thyroid glands. The expression of alpha1beta1, alpha2beta1, alpha3beta1, alpha6beta1, and alpha6beta4 was found in all tumor specimens and in tumor cell lines, whereas normal thyroid cells and TAD-2 cells lacked the expression of alpha6beta4. Despite the presence of several integrin laminin receptors, adhesion of TAD-2, NPA, and ARO cells to immobilized laminin-1 was poor, whereas WRO cells and follicular carcinoma-derived cells displayed a strong adhesion. Indeed, WRO and follicular carcinoma-derived cells showed expression of a nonintegrin laminin receptor, the 67-kDa high affinity laminin receptor (67LR). TAD-2, NPA, and ARO cells as well as nodular goiter, toxic adenoma, follicular adenoma, and papillary carcinoma-derived cells did not express the 67LR. Adhesion of WRO and follicular carcinoma-derived cells to laminin-1 was specifically inhibited by a recombinant polypeptide containing laminin-binding domains of 67LR, demonstrating that this receptor confers to follicular carcinoma cells attachment capacity to laminin. Moreover, tissue specimens from follicular carcinomas expressed the 67LR, whereas follicular adenomas and normal thyroid tissues were negative. In thyroid tumors, integrin receptors, although abundant, participate weakly in adhesion to laminin. The expression in follicular carcinoma cells of a functional, high affinity 67LR together with nonfunctional integrin LM receptors could be responsible for the tendency of follicular carcinoma cells to metastasize by mediating stable contacts with basal membranes.

Expression of the 67-kDa laminin receptor in acute myeloid leukemia cells mediates adhesion to laminin and is frequently associated with monocytic differentiation

Lodgement, proliferation, and migration of leukemic cells within bone marrow (BM) microenvironment involves adhesion of these cells to the BM extracellular matrix molecules fibronectin and laminin. The 67-kDa laminin receptor (67LR) is a nonintegrin protein with high affinity for laminin, which plays a critical role in basement membrane invasion and metastasis of cancer cells. By Western blotting, we documented that 67LR was strongly expressed in myelomonocytic THP1 and histiocytic U937 cells and was weakly expressed in promyelocytic HL-60 cells. In HL-60 cells, 67LR expression almost disappeared after retinoic-induced granulocytic differentiation, whereas it strongly increased after phorbol ester-induced monocytic differentiation. We did not detect 67LR expression in normal BM hematopoietic cells, in precursor-B acute lymphoblastic leukemia, in chronic lymphocytic leukemia, or in chronic myeloid leukemia in chronic phase. By contrast, we detected enhanced 67LR expression in 40% of 53 de novo acute myeloid leukemias (AMLs), which frequently exhibited monocytic or myelomonocytic morphology and expressed CD14 and CD11a (P < 0.05). Using a colorimetric assay, we found that the expression pattern of this receptor corresponded to a higher adhesion to laminin; the adhesion was specific because in vitro addition to laminin-coated wells of recombinant 37-kDa laminin receptor precursor (37LRP), which is the cytoplasmic precursor containing both laminin-binding domains of cell surface 67LR, significantly reduced laminin binding of AML cells. The expression of 67LR on AML cell surface did not correlate with other differentiation and integrin antigens such as CD7, CD13, CD33, CD34, CD11b, CD11c, CD49d, CD49e, CD45RA, and CD45RO. In contrast with 67LR behavior in solid tumors, no statistically significant difference was found between 67LR expression and any hematological characteristic of the disease at diagnosis, nor between 67LR expression and outcome of the disease as measured by complete remission rate, disease-free survival, or overall survival. In conclusion, our results indicate that 67LR expression mediates specific adhesion to laminin and that the detection of this molecule may be a valuable addition to other lineage-associated antigens in identifying monocytic-oriented AML.

[Bochdalek's diaphragmatic hernia in adults. Description of a clinical case]

Bochdalek's hernia is a congenital posterior diaphragmatic defect, resulting from persistence of the pleuroperitoneal canal of embryonic life. Bochdalek's hernias are rare occurrences in adult patients and they present commonly with digestive symptoms and need surgical therapy. This article describes a case of an 88-year-old female with symptomatic right Bochdalek defect containing intra-abdominal viscera with no hernial sac.

[Perforation of primary non-Hodgkin's lymphoma during chemotherapy. Clinical evaluation and therapeutic strategy]

Primary cecal lymphoma are very rare. The case is reported of an elderly woman having voluntary preliminary chemotherapy with consequent cecum perforation due to tumoral necrosis, some days after the first chemotherapy. The diagnostic, clinical and therapeutic protocol is analysed and stress is laid on the rare clinical cases described. Resection is advisable in the still delimited forms in order to avoid surgical complications due to preliminary chemotherapy and in order to classify precisely the neoplasm.

Expression of integrins of the beta1 family in thyroid cells from patients with Graves' disease in vivo and in vitro

The expression of the beta1 family of integrins was determined in thyroid follicular cells from patients with Graves' disease (GD). Integrin expression was quantitated by flow fluorocytometry of single cell suspensions with antibodies against the common beta1 chain and the alpha1-alpha6 subunits. Results indicated that also in thyroid glands of GD, as previously observed in nodular goiters, two follicular cell populations with different patterns of beta1 integrin expression coexist (VLAalpha3beta1 and VLAalpha1,3,5,6beta1). The VLAalpha1,3,5,6beta1 thyrocyte population in GD was more abundant than in nodular goiters, ranging from 40 to 70% of the total follicular cells and the overall expression of the beta1 integrins was a two-fold higher. In thyrocytes from patients with GD cultured in vitro, alpha3 and alpha2 expression was regulated by cell-to-cell contact as previously described in normal thyroid cells, while the expression of alpha1, alpha5 and alpha6 was quickly lost during the culture. Our data suggest that the integrin profile of the VLAalpha1,3,5,6beta1 thyrocyte population in GD is induced by micro-environmental conditions rather than being the expression of a constitutive phenotype.

Air pollution and cause-specific mortality in Milan, Italy, 1980-1989

In several studies, investigators have reported associations among air pollution, weather, and daily deaths, usually from all causes. In the current study, we focused on the difference in lag time between exposure to total suspended particulates or extreme weather and cause-specific mortality in an effort to understand the potential underlying mechanism. We used a robust Poisson regression in a generalized additive model to investigate the association between air pollution and daily mortality. We used a loess smooth function to model season, weather, and humidity; indicator variables for hot days were also used. To examine the relationship in a currently meaningful range, we excluded all days with a total suspended particulate concentration higher than 200 microg/m3. We found a significant association on the concurrent day, both for respiratory infection deaths (11% increase/100 microg/m3 increase in total suspended particulate; 95% confidence interval = 5, 17) and for heart-failure deaths (7% increase; 95% confidence interval = 3, 11). The associations with myocardial infarction (i.e., 10% increase; 95% confidence interval = 3, 18) and chronic obstructive pulmonary disease (12% increase, 95% confidence interval = 6, 17) were found for the means of 3 and 4 d prior to death. We observed an effect of cold weather at lag 1 for respiratory infections and an effect of hot weather at lag 0 for heart failure and myocardial infarctions. The association for all causes and cause-specific deaths was almost identical to that noted previously in Philadelphia, Pennsylvania. Smoothed functions of total suspended particulates suggested a higher slope at lower concentrations, and this finding may account for differences noted between European and U.S. studies. Given that both the dependence between weather and daily mortality and the lag between exposure and death varies by cause of death, analyses by specific causes of death would be very useful in the future.

Urokinase-type plasminogen-activator and normal thyroid cell adhesion to the extracellular matrix

The urokinase-type plasminogen activator receptor (uPA-R) focuses the proteolytic activity of its ligand, the urokinase-type plasminogen activator (uPA), on the cell surface, and can also act as an adhesion receptor for vitronectin (VTN). uPA increases uPA-R affinity for VTN and is also able to cleave its receptor. We have previously shown that uPA-R is involved in the adhesion of normal thyroid cells to VTN. In the present report, we have investigated the effect of uPA on normal thyroid cell adhesion to some extracellular matrix (ECM) components. We show that a short-term treatment with uPA does not change normal thyroid cell adhesion to fibronectin (FNT), collagen (CGN), laminin (LMN) and VTN. The prolongation of uPA treatment increases cell adhesion to VTN, and, less efficiently, to other ECM components. Since the short term uPA treatment causes a partial cleavage of uPA-R, that does not increase with time, the observed increase in cell adhesivity cannot be related to the cleavage of uPA-R. We show that the adhesion improvement after the long term uPA treatment is instead due to a strong increase of the cell-surface expression of the integrin beta3 and a moderate increase of the integrin alpha(v). Both alpha(v) beta3 and alpha(v) beta1 are integrinic receptors for VTN.

A betaPP peptide carboxyl-terminal to Abeta is neurotoxic

Extracellular Abeta-amyloid and intraneuronal paired helical filaments (PHFs) composed of tau protein are the neuropathological hallmark of Alzheimer's disease. Abeta is a 39- to 43-residue peptide derived by cleavage of a 695- to 770-amino-acid membrane-associate glycoprotein (termed beta-protein precursor, betaPP). Following the observation that an antiserum to an epitope located between residues 713 and 723 of betaPP770 (ie, the transmembrane region of the betaPP distal to Abeta) labels PHFs and that a synthetic peptide homologous to residues 713 to 730 of betaPP770 (betaPP713-730) is highly fibrillogenic and interacts with tau in vitro, it has been hypothesized that betaPP fragments other than Abeta may feature in the pathogenesis of Alzheimer's disease concurring with neuronal degeneration. To investigate this issue, we have analyzed the effects of the exposure of primary neuronal cultures to the synthetic peptide betaPP713-730. Cultures were prepared from rat hippocampus on embryonic day 17 and incubated with the peptide at 2.5 to 30 micromol/L concentration for 1 to 4 days. Cell viability was compared with that of control cultures exposed to a scrambled sequence of the peptide. A 4-day exposure to 20 micromol/L betaPP713-730 resulted in almost complete neuronal loss, whereas no changes were observed with the scrambled peptide. Degenerating neurons showed DNA fragmentation by agarose gel electrophoresis and apoptotic changes by light and electron microscopy. These findings support the view that betaPP sequences other than Abeta may play a role in nerve cell degeneration in Alzheimer's disease.

Epidemiologic and genetic factor in colorectal cancer: development of cancer in dizygotic twins in a family with Lynch syndrome

Human tumours usually develop due to a close interaction between environmental and genetic factors. This concept applies also to well defined genetic diseases such as Hereditary Nonpolyposis Colorectal Cancer (HNPCC or Lynch syndrome), which is featured by early onset tumours of the large bowel (and other target organs), striking aggregation of neoplasms in families, and vertical transmission consistent with an autosomal dominant pattern of inheritance. As a further example of gene/environment interaction, we report on a Hereditary Nonpolyposis Colorectal Cancer family in which two dizygotic twins were affected by cancer of the large bowel. One of the twins was slightly overweight and showed many common risk factors for colorectal carcinoma; he developed a Dukes' C lesion at the age of 52 years. The other twin was not overweight and was much less exposed to exogenous risk factors; a Dukes' B carcinoma was diagnosed at age 60, during a control endoscopy. This anedoctal report suggests that diet and lifestyle are of relevance also in patients with genetically determined tumours of the large bowel. It follows that the control of these environmental factors might be associated with a delay of tumour occurrence and possibly with a less aggressive tumour behaviour.

Thyroid hormone effects on mouse oocyte maturation and granulosa cell aromatase activity

In the present study we evaluated the role of T3 on the in vitro processes of mouse cumulus cell-oocyte complex expansion, oocyte meiotic maturation, and granulosa cell aromatase activity. Results obtained from cumuli oophori isolated from immature and adult mice ovaries demonstrated that T3 at all concentrations tested (0.1-100 nM) did not affect basal or FSH-induced cumulus expansion or interfere with oocyte meiotic maturation up to metaphase II stage. On the contrary, T3 inhibited in a time- and dose-dependent manner FSH-induced aromatase activity in cultured granulosa cells obtained from either adult or immature female mice. The half-maximal dose (ED50) of T3 inhibition was 0.87 +/- 0.21 nM, which is in agreement with the reported dissociation constant of T3 nuclear receptor (Kd = 0.4-5 nM) in mammalian granulosa cells. Time-course experiments demonstrated higher sensitivity to T3 of adult granulosa cells with respect to immature granulosa cells in culture. Indeed, in immature granulosa cells T3 inhibition became significantly evident only after 6 days of hormonal treatment, whereas in adult granulosa cells the inhibitory effect was present after only 2 days of treatment. (Bu)2cAMP- or 3-isobutyl-1-methyl-xanthine-stimulated aromatase activity was also significantly decreased by T3, thus suggesting that the inhibition was downstream from cAMP formation. Lastly, analysis of aromatase messenger RNA (mRNA) levels by semiquantitative RT-PCR demonstrated the ability of FSH to increase aromatase mRNA level in cultured granulosa cells by 2.4 +/- 0.5-fold. In agreement with the effect on enzyme activity, the stimulatory effect of FSH on aromatase mRNA level was greatly reduced after T3 cotreatment. In conclusion, T3 inhibition of aromatase activity may be of physiological relevance in the complex multihormonal regulation of mammalian follicle development and may contribute to explaining the alteration in female reproductive functions after thyroid hormone hypo- or hypersecretion.

Microsatellite instability in multiple colorectal tumors

Tumor multiplicity is a hallmark of hereditary cancers: in the colon-rectum multiple tumors represent 5-10% of all colorectal cancer cases. A portion of these cases belongs to hereditary non-polyposis colorectal cancer (HNPCC), a genetic cancer syndrome due to mismatch repair (MMR) gene mutations, phenotypically expressed as microsatellite instability (MSI); the majority of multiple tumors, however, is apparently without any family history. We analyzed 78 (38 synchronous and 40 metachronous) neoplasms from 37 patients with multiple tumors of the large bowel, both HNPCC and sporadic, with the aim of identifying a common genetic basis in multiple tumors. DNA was extracted from normal and cancerous formalin-fixed tissue and was analyzed for MSI using 6 markers. Tumors showing MSI in at least 2 of 6 microsatellite loci were defined as MSI(+). The overall number of MSI(+) tumors was 22 (28.2% of the total). A significant difference in the rate of MSI(+) between HNPCC and sporadic tumors was observed (85% vs. 17%). In the same patients, the MSI phenotype of synchronous tumors (both HNPCC and sporadic) tended to be more concordant than that of the metachronous ones. The higher frequency of MSI in HNPCC than in sporadic tumors, even when multiple, suggests that the involvement of MMR genes in the pathogenesis of the sporadic cases may be uncommon, thus confirming that screening for MSI in multiple colorectal tumors could be a useful tool in the identification of HNPCC in the general population.

Microsatellite instability in multiple colorectal tumors

Tumor multiplicity is a hallmark of hereditary cancers: in the colon-rectum multiple tumors represent 5-10% of all colorectal cancer cases. A portion of these cases belongs to hereditary non-polyposis colorectal cancer (HNPCC), a genetic cancer syndrome due to mismatch repair (MMR) gene mutations, phenotypically expressed as microsatellite instability (MSI); the majority of multiple tumors, however, is apparently without any family history. We analyzed 78 (38 synchronous and 40 metachronous) neoplasms from 37 patients with multiple tumors of the large bowel, both HNPCC and sporadic, with the aim of identifying a common genetic basis in multiple tumors. DNA was extracted from normal and cancerous formalin-fixed tissue and was analyzed for MSI using 6 markers. Tumors showing MSI in at least 2 of 6 microsatellite loci were defined as MSI(+). The overall number of MSI(+) tumors was 22 (28.2% of the total). A significant difference in the rate of MSI(+) between HNPCC and sporadic tumors was observed (85% vs. 17%). In the same patients, the MSI phenotype of synchronous tumors (both HNPCC and sporadic) tended to be more concordant than that of the metachronous ones. The higher frequency of MSI in HNPCC than in sporadic tumors, even when multiple, suggests that the involvement of MMR genes in the pathogenesis of the sporadic cases may be uncommon, thus confirming that screening for MSI in multiple colorectal tumors could be a useful tool in the identification of HNPCC in the general population.

Cochlear implant and traumatic lesions secondary to electrode insertion

On the basis of data reported in the literature, the authors have attempted to define the relationship between the functional results of cochlear implants and possible traumatic damage caused by the insertion of electrodes and their support into the cochlear bony walls. These findings show that traumatic conditions result in functional damage only when they involve the body of Corti's ganglion cells or the central part of their axon, whereas functional results are not influenced by traumatic damage to the peripheral part of the axon. Traumatic damage sustained by other non-nervous structures and the inevitable fibrosis and subsequent bone metaplasia processes which occur when a foreign body penetrates a living organism also appear to be unimportant.

Induction-consolidation with an idarubicin-containing regimen, unpurged marrow autograft, and post-graft chemotherapy in adult acute lymphoblastic leukaemia

Between 1991 and 1993 we conducted a collaborative trial in adult acute lymphoblastic leukaemia, introducing an idarubicin (IDA)-containing regimen for induction and early consolidation, and increasing consolidation intensity with an autologous bone marrow transplantation phase (ABMT, patients aged <51 years) followed by further chemotherapy for 12 weeks and low-dose maintenance for 6 months (ABMT patients) or 18 months. 96 patients were evaluable for antileukaemic response after induction with vincristine-prednisone-L-asparaginase plus cumulative IDA 36 or 20 mg/m2 (IVAP-1 and IVAP-2), and for disease-free survival (DFS) after a minimum follow-up >3.5 years with an off-therapy interval >1.5 years. The response rate was 44% (7/16) with IVAP-1 and 90% (72/80) with IVAP-2 (P=0.0001), due to regimen-related toxicities. Post-remission therapy was administered as planned to most cases but protocol violation was registered in some patients eligible to ABMT and post-graft chemotherapy. The 5-year disease-free survival (DFS) rate was 31%. Multivariate analysis indicated that DFS was improved in patients receiving a transplant (11 allogeneic, DFS 70%; 32 ABMT, 36%; 37 neither, 17%; P < 0.001) and was negatively affected by high-risk features such as blast cell count >25x10(9)/l, T-cell or mature B-cell immunophenotype, and t(9;22)/t(4;11) (all P values <0.05). The 5-year DFS rate was 54% for 26 patients with no high-risk factor, 26% for 35 patients with any one, and 6% for 18 patients with any two (P<0.005). IVAP-2 brought about a high complete response rate and post-remission treatment including ABMT was feasible and modestly toxic. In spite of the short post-graft chemotherapy phase, the long-term DFS rate was good in cases with no high-risk feature. However, because autografting may be redundant in the standard-risk category, its role requires further investigation for high-risk cases.

[The surgical treatment of nonpalpable breast carcinomas]

The wide-spreading use of mammography in clinical approach and in screening programmes contributed to a sensible modification in the population of patients affected by breast malignancies. A special increase has been recorded in non-palpable breast tumors. The Authors have analyzed a total of 135 patients with impalpable breast lesions during the period 1990-1997. All patients underwent fine needle stereotactic aspiration for cytology and in the meantime the lesions were marked with charcoal suspension and within 15 days time a surgical open biopsy was performed. The subgroup of malignant lesions was then surgically treated either with radical quadrantectomy or mastectomy. The results of the analysis confirmed that fine needle biopsy is an imperfect test because of its low sensibility and impossibility of distinguishing between infiltrating and "in situ" carcinomas; the stereotactic tattooing of the lesions is reliable for surgical approach. The rate of in situ carcinomas is remarkably higher than in non selected group of patients affected by palpable cancers. Pathologic staging confirms that non-palpable tumors are of better prognosis and they should benefit in large majority of a conservative surgical treatment.

[The use of the pleural tent in superior lobectomies]

Persistent pleural space must be considered a possible complication after lung resection surgical treatment. Although in most cases the evolution is favourable, the authors suggest the use of the "pleural tent" technique, that compared to others thoracoplasty procedures offers some advantages. A short historical review of the thoracoplasty techniques is presented together with a detailed description of the above-mentioned technique.

Prenyltransferase inhibitors induce apoptosis in proliferating thyroid cells through a p53-independent CrmA-sensitive, and caspase-3-like protease-dependent mechanism

The inhibitors of protein prenylation have been proposed for chemotherapy of tumors. Lovastatin, a 3-hydroxy-3-methylglutaryl-Coenzyme A (HMG-CoA) reductase inhibitor, displays proapoptotic activity in tumor cells blocking the synthesis of isoprenoids compounds. To test whether HMG-CoA reductase inhibition can induce apoptosis in proliferating thyroid cells, we studied the effects of lovastatin in normal and neoplastic thyroid cells and in primary cultures from normal human thyroids. In an immortalized human thyroid cell line (TAD-2) and in neoplastic cells, lovastatin induced cell rounding within 24 h of treatment. After 48 h the cells were detached from the plate and underwent apoptosis, as evidenced by DNA fragmentation. Morphological changes and apoptosis did not occur in serum-starved quiescent TAD-2 cells or in primary cultures of normal thyrocytes. Mevalonate, the product of the HMG-CoA reductase enzymatic activity, and the protein synthesis inhibitor cycloheximide completely blocked the effects of lovastatin in a dose-dependent fashion. The geranylgeranyl transferase GGTI-298 inhibitor mimicked the effects of lovastatin on cell morphology and induced cell death, whereas the farnesyl transferase inhibitor FTI-277 was less effective to induce both cell rounding and apoptosis. Resistance to lovastatin-induced apoptosis by expression of the viral serpine CrmA and by the peptide inhibitor of caspases, Z-DEVD-fmk, demonstrated the involvement of CrmA-sensitive, caspase-3-like proteases. Inhibition of endogenous p53 activity did not affect the sensitivity of thyroid cells to lovastatin, demonstrating that this type of apoptosis is p53 independent. We conclude that lovastatin is a potent inducer of apoptosis in proliferating thyroid cells through inhibition of protein prenylation. This type of apoptosis requires protein synthesis, is CrmA sensitive and caspase-3-like protease dependent, and is independent from p53.