Inhibition of cellular ras prevents smooth muscle cell proliferation after vascular injury in vivo

Proliferation of smooth muscle cells of the arterial wall in response to local injury is an important aetiologic factor of vascular proliferative disorders such as atherosclerosis and restenosis after angioplasty. Ras proteins are key transducers of mitogenic signals from membrane to nucleus in many cell types. We investigated the role of ras proteins in the vascular response to arterial injury by inactivating cellular ras of rats in which the common carotid artery was subjected to balloon injury. DNA vectors expressing ras transdominant negative mutants, which interfere with ras function, reduced neointimal formation after injury. Our results indicate a key role for ras in smooth muscle cell proliferation and show that the local delivery of transdominant negative mutants of ras in vivo might prevent some of the acute vascular injury caused by balloon injury.

Activation of cAMP-PKA signaling in vivo inhibits smooth muscle cell proliferation induced by vascular injury

Injury of the arterial wall induces the formation of the neointima. This structure is generated by the growth of mitogenically activated smooth muscle cells of the arterial wall. The molecular mechanism underlying the formation of the neointima involves deregulated cell growth, primarily triggered by the injury of the arterial wall. The activated gene products transmitting the injury-induced mitogenic stimuli have been identified and inhibited by several means: transdominant negative expression vectors, antisense oligodeoxynucleotides, adenovirus-mediated gene transfer, antibodies and inactivating drugs. Results of our study show that local administration of 3',5'-cyclic AMP and phosphodiesterase-inhibitor drugs (aminophylline and amrinone) to rats markedly inhibits neointima formation after balloon injury in vivo and in smooth muscle cells in vitro. The growth inhibitory effect of aminophylline was completely reversed by the inhibition of cAMP-dependent protein kinase A (PKA). These findings indicate an alternative approach to the treatment of diseases associated with injury-induced cell growth of the arterial wall, as stimulation of cAMP signaling is pharmacologically feasible in the clinical setting.

The v-Ki-Ras oncogene alters cAMP nuclear signaling by regulating the location and the expression of cAMP-dependent protein kinase IIbeta

The v-Ki-Ras oncoprotein dedifferentiates thyroid cells and inhibits nuclear accumulation of the catalytic subunit of cAMP-dependent protein kinase. After activation of v-Ras or protein kinase C, the regulatory subunit of type II protein kinase A, RIIbeta, translocates from the membranes to the cytosol. RIIbeta mRNA and protein were eventually depleted. These effects were mimicked by expressing AKAP45, a truncated version of the RII anchor protein, AKAP75. Because AKAP45 lacks membrane targeting domains, it induces the translocation of PKAII to the cytoplasm. Expression of AKAP45 markedly decreased thyroglobulin mRNA levels and inhibited accumulation of C-PKA in the nucleus. Our results suggest that: 1) The localization of PKAII influences cAMP signaling to the nucleus; 2) Ras alters the localization and the expression of PKAII; 3) Translocation of PKAII to the cytoplasm reduces nuclear C-PKA accumulation, resulting in decreased expression of cAMP-dependent genes, including RIIbeta, TSH receptor, and thyroglobulin. The loss of RIIbeta permanently down-regulates thyroid-specific gene expression.

A common mechanism underlying the E1A repression and the cAMP stimulation of the H ferritin transcription

Transcription of the H ferritin gene in vivo is stimulated by cAMP and repressed by the E1A oncoprotein. We report here the identification of the cis-element in the human promoter responsive to both cAMP- and E1A-mediated signals. This promoter region is included between positions -62 to -45 and binds a approximate 120-kDa transcription factor called Bbf. Bbf forms a complex in vivo with the coactivator molecules p300 and CBP. Recombinant E1A protein reduces the formation of these complexes. In vivo overexpression of p300 in HeLa cells reverses the E1A-mediated inhibition of the ferritin promoter transcription driven by Bbf. These data suggest the existence of a common mechanism for the cAMP activation and the E1A-mediated repression of H ferritin transcription.

Follicle cell proteasome activity and acid extract from the egg vitelline coat prompt the onset of self-sterility in Ciona intestinalis oocytes

In the hermaphrodite ascidian Ciona intestinalis, the egg vitelline coat (VC) controls gamete self-nonself discrimination. Oocytes, after germinal vesicle breakdown, can be fertilized by both self and nonself sperm. However, a barrier to fertilization by self sperm progressively develops in the VC in the 3 hours after germinal vesicle breakdown. During this period, follicle cells attached to the outer surface of the VC release self-sterility factors that bind to the VC. Within the follicle cells, these factors (possibly peptides) are thought to be shuttled to the cell membrane by an hsp70 homolog (Cihsp70). In fact, antibodies to hsp70 block the development of self-sterility. Proteasomes are central to the production of antigen peptides. Specific inhibition of proteasome activity with clasto-lactacystin beta-lactone (CLbetaL) prevented the onset of self-sterility, but had no effect once this process had started. CLbetaL did not block fertilization by nonself sperm. The self-sterility factors were removed from mature oocytes by exposure to acidified media, and their biological activity was transferred to immature oocytes treated with CLbetaL. The obvious high multiplicity of self-nonself recognition alleles involved in fertilization, and the involvement of an hsp70 and a proteasome in processing self-sterility factors, suggests that this system may be evolutionarily related to the vertebrate immune system.

Identification and developmental expression of Ci-isl, a homologue of vertebrate islet genes, in the ascidian Ciona intestinalis

Here we describe the cloning and expression pattern of Ci-isl, a homologue of vertebrate genes, in the ascidian. Early in development, Ci-isl expression occurs in the primordia of palps and brain vesicle, then in the tailbud embryo it is transiently extended to the notochord cells. At larva stage, the expression is down-regulated in the notochord, and it persists predominantly in the compartments of the nervous system. These observations indicate that also in invertebrates, islet genes show an expression pattern during differentiation of the nervous system.

Distribution pattern of hepatitis C virus genotypes and correlation with viral load and risk factors in chronic positive patients

OBJECTIVE

Hepatitis C virus (HCV) has emerged as a leading cause of chronic hepatitis, liver cirrhosis and hepatocellular carcinoma worldwide. The purpose of this study was to describe the distribution pattern of HCV genotypes in chronic hepatitis patients in the Campania region of southern Italy and estimate their association with risk factors and viral load.

MATERIALS AND METHODS

404 consecutive HCV ribonucleic acid-positive patients were included in the study. HCV genotyping was carried out by the HCV line probe assay test and viral load estimation by the TaqMan real-time PCR system.

RESULTS

The predominant genotype was 1 (63.6%), followed by genotype 2 (29.4%), 3 (6.2%) and 4 (0.8%). Subtype 1b was more frequent in females than in males. Conversely, genotype 3 was more frequent in males. No significant difference was observed in age distribution of HCV genotypes. Surgery and dental therapy were the most frequent risk factors for genotype 1 and intravenous drug abuse and tattooing for genotype 3. Patients with genotype 1 more frequently showed high HCV viral load when compared to those with genotypes 2 and 3.

CONCLUSION

The present study revealed that HCV genotypes 1 and 2 accounted for over 95% of all HCV infections in the Campania region, and genotype 1 was more frequently associated with a higher viral load when compared to genotypes 2 and 3.

The sustainability of a community nurses programme aimed at supporting active ageing in mountain areas

BACKGROUND

Community Nurse Supporting Elderly iN a changing SOciety is a project funded by the European Union, which is aimed at developing an innovative care model based on community nurses to support active ageing in mountain areas. The planned sustainability of this innovative approach relies on social entrepreneurship, and this work highlights the necessary conditions for the existence of these entrepreneurial initiatives on the market, with community nurses' services purchased by the public health care system.

METHODS

The authors propose a sustainability framework for this project based on three relevant dimensions (ie, health, organisation, and context), highlighting the necessary conditions for continued provision of health services beyond project conclusion. Then, considering the Piedmont Region and those aged 65 or older as target population, health outcomes are analysed, proposing a break-even analysis to calculate expected levels.

RESULTS

According to our results, in order to care for 191 977 elderly people for 3 years, a successful pro-active approach is needed to prevent 1657 falls with hip fracture, reducing the prevalence of this adverse outcome by 36%. These are the expected health outcome levels for the existence of a social market, which can be achieved through the successful involvement of local public health organisations and stakeholders.

CONCLUSIONS

Policy makers need clear information on the economic impact of extending this new intervention to the whole target population and on the required preconditions for its financial sustainability in terms of health outcomes. However, a participatory process involving all relevant local stakeholders and organisations is crucial to extend current achievements beyond project conclusion.

Advantages of immediate two-dimensional echocardiography in patients with acute cardiac ischemic events

We hypothesized that the assessment of kinetic alterations on two dimensional echocardiogram (2DE) would provide greater diagnostic information than clinical symptoms and ECG changes only. The study was aimed to determine sensitivity of 2DE in patients with cardiac ischemic events and to improve the indications to thrombolysis. Three-hundred ninety-one patients (87 F; 304 M) hospitalized for suspected acute myocardial infarction (AMI), first episode, within 4 h from the onset of symptoms, suitable for thrombolysis Killip class I-II and with unstable angina (UA), were admitted in the study. Patients had to show ECG changes and alterations of segmentary motion on 2DE performed at entry, or 2DE alterations without ECG changes. The 2DE variables analyzed included right ventricular function and left ventricular systolic function. Thrombolysis was performed when 2DE and ECG changes were evidenced at the same time and when 2DE alterations without ECG changes were observed. Patients with UA treated with heparin alone were also studied. The presence of segmentary motion alterations was mandatory.

RESULTS

Inferior AMIs, 87 patients (60 +/- 13 years), anterior AMI, 169 patients (61 +/- 11 years); UA group subjected to thrombolysis, 87 patients (62 +/- 12 years); UA group treated with heparin, 48 patients (62 +/- 12 years). We noted only one patient false negative, and five patients false positive. Alterations of right ventricular function were observed in 24, 14 and nine patients with inferior, anterior AMI and UA, respectively. Normal ECG at entry was observed in seven, two and seven patients with inferior, anterior AMI and UA, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of the use of platelet-rich plasma gel on local recurrence in an animal model of human fibrosarcoma

Background

Platelet-rich-plasma (PRP) is largely used, thanks to its properties, as wound therapy after surgical resection. Several studies and clinical findings have demonstrated that the PRP can accelerate the regeneration and the repair of tissues through the action of the platelet-derived growth factors.

Material and methods

Our study aimed to investigate the effects of PRP-gel on the rate of tumor relapse by using a mouse model of Human Fibrosarcoma (HF). The radical resection of tumors of mice was conducted under fluorescence-guidance (FGR) by using MacroFluo microscope, after a primary tumor removal with bright-light surgery (BLS).

Results

It was found that the lesion recurrence and the tumor growth were reduced in mice treated with PRP observed in each group of treatment (50%) after 30 days from tumor excision, respect to controls (without statistical significance; p = 0.12). The histopathological and immune-histochemical analysis did not report differences in cellular morphology between the tumors of control and PRP-treated mice.

Conclusion

Our data suggest that PRP-gel, used as an adjuvant treatment for the stimulation of tissue repair and speed up recovery, can impair tumor growth and slow the tumor.

Serial RT-PCR detection of circulating tumour cells as a marker of disease progression in patients with malignant melanoma

18009

Background: Detection of circulating malignant cells (CMCs) through a reverse transcriptase-polymerase chain reaction (RT-PCR) assay seems to be a demonstration of systemic disease. We here evaluated the prognostic role of RT-PCR assays in serially-taken peripheral blood samples from patients with malignant melanoma (MM). Methods: One hundred forty-nine melanoma patients with disease stage ranging from I to III were consecutively collected in 1997. A multi-marker RT-PCR assay was used on peripheral blood samples obtained at time of diagnosis and every 6 months during the first two years of follow-up (total: 5 samples). Univariate and multivariate analyses were performed after 83 months of median follow-up. Results: Detection of at least one circulating mRNA marker was considered a signal of the presence of CMC (referred to as PCR-positive assay). A significant correlation was found between the rate of recurrences and the increasing number of PCR-positive assays (P = 0.007). Presence of CMC in a high number (≥2) of analysed blood samples was significantly correlated with a poor clinical outcome (disease-free survival: P = 0.019; overall survival: P = 0.034). Multivariate analysis revealed that presence of a PCR-positive status does play a role as independent prognostic factors for overall survival in melanoma patients, adding precision to the predictive power of the disease stage. Conclusions: Our findings indicated that serial RT-PCR assay may identify a high risk subset of melanoma patients with occult cancer cells constantly detected in blood circulation. Prolonged presence of CMCs seems to act as a surrogate marker of disease progression or a sign of more aggressive disease.

No significant financial relationships to disclose.

Changes in CMR parameters and prediction of cardiac complications in thalassemia major: fibrosis tells us more than iron

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): The MIOT project received “no-profit support” from industrial sponsorships (Chiesi Farmaceutici S.p.A. and ApoPharma Inc.).

Background

Cardiovascular magnetic Resonance (CMR) has dramatically changed the clinical practice and improved the prognosis in thalassemia major (TM).

Aim

This is the first study evaluating the predictive value of changes in CMR parameters (myocardial iron, function, and fibrosis) for cardiac complications in TM.

Methods

We followed prospectively 709 TM patients (374 females; 29.77 ± 8.53 years) consecutively enrolled in the Myocardial Iron Overload in Thalassemia (MIOT) Network who performed a baseline and a 1st follow up CMR scan after 18 months.  Myocardial iron overload (MIO) was measured by multislice multiecho T2* technique and atrial dimensions and biventricular function by cine images. Macroscopic myocardial fibrosis was detected by late gadolinium enhancement technique.

Risk classes were defined based on  the 4 patterns of MIO from worst to normal. For patients with baseline MIO (at least one segmental T2*<20 ms), improvement was defined as a transition to a better risk class, stabilization as no change in risk class, and worsening as a transition to a worse risk class. For patients without baseline MIO, the worsening was the transition to a worse risk class.

The percentage change was used for continuous variables. For biventricular ejection fractions, improvement was a %change > 10%, stabilization a %change between -10% and 10%, and worsening a %change<-10%. For biventricular volumes, LV mass index, and atrial areas, improvement was a % change<-10%, stabilization a % change between -10% and 10%, and worsening a % change > 10%.

Myocardial fibrosis was considered absent if not detected in any of the two CMRs and present if detected in at least one examination.

Results

During a mean follow-up of 89.4 ± 33.3 months, cardiac events were recorded in 50 (7.1%) patients: 24 (48%) episodes of heart failure, 24 (48%) arrhythmias (23 supraventricular and 1 hypokinetic), and 2 (4.0%) pulmonary hypertension.  Mean time from the 1st follow up CMR to the development of a cardiac complication was 75.31 ± 35.35 months.

In the univariate Cox regression analysis, cardiac iron cleareance and myocardial fibrosis were identified as univariate prognosticators (Table 1). In the multivariate analysis only myocardial fibrosis remained an independent predictor factor.

Conclusion

The presence of myocardial fibrosis at the baseline CMR or developed within 18 months emerges as the strongest long-term predictor for cardiac complications in TM. Our data demonstrate the importance in using the contrast medium for CMR scans in thalassemia patients.

Inhibition of c-ras reactivates thyroglobulin synthesis in middle-T transformed thyroid cells

Differentiated thyroid cells expressing polyoma Middle-T became transformed and tumorigenic when injected into syngenic animals. The expression of thyroglobulin was greatly reduced and no longer responsive to thyrotropin (TSH) and to cAMP. Inhibition of endogenous c-ras by the expression of two transdominant negative mutant H-ras genes, Asn17 and Leu61-Ser186, reactivated thyroglobulin synthesis. Reactivation of thyroglobulin synthesis by c-ras inhibition was not observed in the absence of TSH. These findings indicate that MT elicits dedifferentiation of thyroid cells by activating endogenous c-ras and that c-ras interferes with TSH or cAMP signaling.