Diffuse C-Cells Hyperplasia Is the Source of False Positive Calcitonin Measurement in FNA Washout Fluids of Thyroid Nodules: A Rational Clinical Approach to Avoiding Unnecessary Surgery

PURPOSE

The FNA-CT is useful for the diagnosis of MTC. The aim of this study was to evaluate the performance of FNA-CT in TNs coexisting with CCH.

METHODS

This study retrospectively reviewed the records of 11 patients with TNs submitted to thyroidectomy on the basis of elevated basal and/or stimulated serum CT values, which at histology were not confirmed to be MTC. The results obtained in this group were compared with those of a previously reported group of histologically proven MTC patients submitted to an identical presurgical evaluation. All patients, negative for known mutations in the RET proto-oncogene, were preoperatively submitted to neck ultrasound, FNA-cytology, and FNA-CT.

RESULTS

Approximately 6 of 11 patients showed increased (>36 ng/mL, as established in previous studies not involving patients with CCH) FNA-CT. All these patients showed diffuse CCH at histology in the thyroid lobe submitted to FNA; 5 of them were benign at histology, while only one was malignant (papillary thyroid carcinoma, PTC). The remaining 5 of 11 patients had low FNA-CT (<36 ng/mL), and all of them showed only focal CCH in the lobe submitted to FNA; three of them were malignant (2 PTC, 1 follicular carcinoma), while two were benign.

CONCLUSIONS

Employing the currently proposed cut-off values, false-positive FNA-CT results may be observed in benign/malignant TNs with coexisting diffuse CCH. FNA-CT must therefore be cautiously used in the diagnostic approach for patients with TNs and a slightly increased basal or stimulated serum CT concentration in order to avoid unnecessary surgery.

P44 PREDICTORS OF MORTALITY AFTER ACUTE TYPE A AORTIC DISSECTION REPAIR IN PATIENTS OF 70 YEARS OF AGE OR OLDER

Objectives

The impact of age on outcomes of acute type A aortic dissection remains controversial. We sought to investigate 30–day and follow–up outcomes of acute type A aortic dissection repair in elderly patients. Survival anlysis was performed and independent risk factors for mortality were searched.

Methods

During a 21–year period (2000–2021), 102 patients of 70 years of age or older were emergently treated for acute type A aortic dissection at our institution. (mean age 75.1 ± 3.8 years, 53.9% male) Preoperative characteristics are displayed in Table I.

Results

Overall 30–day mortality (including operative mortality) was 21.6%. Mortality increased among patients presenting with atrial fibrillation (adjusted odds ratio 10.33, P = 0.02) and visceral malperfution (adjusted odds ratio 70.88, P = 0.005). Survival at 1, 5 and 10 years was 70.2 ± 4.6%, 50.9 ± 5.6% and 24.1 ± 5.6%, respectively (Figure 1). The need to perform concomitant coronary artery bypass grafting was the only independent risk factor for mortality during follow–up. (adjusted odds ratio 2.21, P = 0.04)

Conclusions

Thirty –day and follow–up mortality were extremely satisfactory in elderly patients undergoing acute type A dissection repair. We could detect significant disease and surgery–related risk factors for death. Patients presenting with atrial fibrillation or visceral malperfusion had the poorest 30–day outcome. The need to perform concomitant coronary artery bypass grafting, significantly increased the mortality during follow–up.

Interplay between synthetic conditions and micromorphology in poly(3,4-ethylenedioxythiophene):tosylate (PEDOT:Tos): an atomistic investigation

A systematic analysis was performed to elucidate the role played by proton scavengers in PEDOT chain length distribution and micromorphology.

Clinical and ultrasound features of benign, borderline, and malignant invasive mucinous ovarian tumors

OBJECTIVE

To compare clinical and sonographic features of benign, borderline, and malignant invasive mucinous ovarian tumors (MOTs).

MATERIALS AND METHODS

Retrospective observational multicenter study comprising 365 women (mean age: 46.1 years) with a histologically confirmed benign, borderline or malignant invasive MOT. Clinical data (patient's age, patient's complaints), tumor markers (CA-125 and CA-1 9.9), and sonographic data (tumor size, bilaterality, morphology -unilocular, multilocular, unilocular-solid, multilocular-solid and solid-, and IOTA color score) were reviewed and compared among these three groups. Women with ultrasound evidence on intra-abdominal disease spread were excluded.

RESULTS

Three hundred seventy-eight MOTs (14 women had bilateral lesions) were analyzed. Histologically, 287 tumors were benign, 51 were borderline, and 40 were malignant. No difference in patient's mean age was observed. Women with borderline or invasive tumors were less frequently asymptomatic. Tumors were larger in case of invasive lesions. Borderline and invasive tumors showed solid components and exhibited IOTA color score 3 or 4, more frequently than benign lesions (p < 0.001). However, the authors discovered that 16 out of 51 (31.4%) of borderline tumors and six out of 40 (15.0%) of invasive cancers had no solid components and a color score 1 or 2, and were considered as a benign lesion by the sonolo- gist. On the other hand, 96 out of 287 (33.4%) benign mucinous cystadenoma exhibited solid components and/or a color score of 3 or 4.

CONCLUSIONS

In spite of statistical differences, the authors observed significant overlapping in ultrasound features among benign, borderline, and invasive ovarian mucinous tumors that renders a difficult accurate preoperative discrimination among these lesions.

David operation: single center 10-year experience

AIM

Aortic valve-sparing operation has been progressively widely performed for the treatment of aortic root aneurysm. Nowadays, this procedure has been proposed even in presence of a bicuspid aortic valve, severe aortic regurgitation or in primary aortic dissection repair. We present our ten-year experience focusing on mid-term echocardiographic follow-up.

METHODS

Between June 2002 and February 2012, 139 patients (mean age of 61±12 years) underwent aortic valve-sparing operation with valve reimplantation. Twenty-seven patients (19%) had bicuspid aortic valve; in eighteen cases (13%) cusp motion or anatomical abnormalities concurred in determining aortic regurgitation and needed an adjunct cusp repair. A Gelweave Valsalva™ graft was implanted in all the patients.

RESULTS

The mortality pre-discharge was 0.7% (1 patient). The cumulative 1-year, 5-years and 8-years survival rates were 99%, 93% and 87% respectively. Postoperative aortic regurgitation more than mild degree (>2+/4+) was the only significant risk factors for redo aortic valve surgery Freedom from reoperation due to aortic valve regurgitation was 96% at 1 year, 90% at 5 years and 86% at 8 years. When comparing freedom from reoperation in patients with bicuspid vs tricuspid aortic valve, no differences were found (P=0.31) and the rate of aortic valve reoperation was significantly higher (P<0.001) in patients who received leaflet's repair.

CONCLUSION

The durability of valve reimplantation was found to be excellent in patients with tricuspid aortic valve and normal or nearly normal cusps. Cusp prolapse and complication after cusp repair turned out to be the main causes for early failure.

Functional characterization of a CDKN1B mutation in a Sardinian kindred with multiple endocrine neoplasia type 4 (MEN4)

Inactivating germline mutations of the CDKN1B gene, encoding for the nuclear cyclin-dependent kinase inhibitor p27kip1 protein, have been reported in patients with multiple endocrine neoplasia type 4 (MEN4), a MEN1-like phenotype without MEN1 mutations. The aim of this study was to in vitro characterize the germline CDKN1B mutation c.374_375delCT (S125X) we detected in a patient with MEN4. The proband was affected by multiglandular primary hyperparathyroidism and gastro-entero-pancreatic tumors. We carried out subcellular localization experiments transfecting into eukaryotic HeLa and GH3 cell lines plasmid vectors expressing the CDKN1B wild type (wt) or mutant cDNA. Western blot studies showed that fusion proteins were expressed at equal levels. The mutated protein was shorter compared to the wt protein and lacked the highly conserved C-terminal domain, which includes the bipartite nuclear localization signal at amino acids 152/153 and 166/168. In HeLa and GH3 cells wt p27 localized in the nucleus whereas the p27_S125X protein was retained in the cytoplasm predicting the loss of tumor suppressive function. The proband's tumoral parathyroid tissue did not show allelic loss, since wt and mutant alleles were both present by sequencing the somatic DNA. Immunohistochemistry showed a complete loss of nuclear p27 expression in the parathyroid adenoma removed by the patient at the second surgery. In conclusion, our study confirms the pathogenic role of the c.374_375delCT CDKN1B germline mutation in a patient with MEN4.

Assessing RET/PTC in thyroid nodule fine-needle aspirates: the FISH point of view

RET/PTC rearrangement and BRAF(V600E) mutation are the two prevalent molecular alterations associated with papillary thyroid carcinoma (PTC), and their identification is increasingly being used as an adjunct to cytology in diagnosing PTC. However, there are caveats associated with the use of the molecular approach in fine-needle aspiration (FNA), particularly for RET/PTC, that should be taken into consideration. It has been claimed that a clonal or sporadic presence of this abnormality in follicular cells can distinguish between malignant and benign nodules. Nevertheless, the most commonly used PCR-based techniques lack the capacity to quantify the number of abnormal cells. Because fluorescence in situ hybridization (FISH) is the most sensitive method for detecting gene rearrangement in a single cell, we compared results from FISH and conventional RT-PCR obtained in FNA of a large cohort of consecutive patients with suspicious nodules and investigated the feasibility of setting a FISH-FNA threshold capable of distinguishing non-clonal from clonal molecular events. For this purpose, a home brew break-apart probe, able to recognize the physical breakage of RET, was designed. While a ≥3% FISH signal for broken RET was sufficient to distinguish nodules with abnormal follicular cells, only samples with a ≥6.8% break-apart FISH signal also exhibited positive RT-PCR results. On histological analysis, all nodules meeting the ≥6.8% threshold proved to be malignant. These data corroborate the power of FISH when compared with RT-PCR in quantifying the presence of RET/PTC in FNA and validate the RT-PCR efficiency in detecting clonal RET/PTC alterations.

Functioning glucagonoma associated with primary hyperparathyroidism: multiple endocrine neoplasia type 1 or incidental association?

BACKGROUND

Diagnosis of multiple endocrine neoplasia type 1 (MEN1) is commonly based on clinical criteria, and confirmed by genetic testing. In patients without known MEN1-related germline mutations, the possibility of a casual association between two or more endocrine tumors cannot be excluded and subsequent management may be difficult to plan. We describe a very uncommon case of functioning glucagonoma associated with primary hyperparathyroidism (pHPT) in which genetic testing failed to detect germline mutations of MEN-1 and other known genes responsible for MEN1.

CASE PRESENTATION

The patient, a 65-year old woman, had been suffering for more than 1 year from weakness, progressive weight loss, angular cheilitis, glossitis and, more recently, skin rashes on the perineum, perioral skin and groin folds. After multidisciplinary investigations, functioning glucagonoma and asymptomatic pHPT were diagnosed and, since family history was negative, sporadic MEN1 was suspected. However, genetic testing revealed neither MEN-1 nor other gene mutations responsible for rarer cases of MEN1 (CDKN1B/p27 and other cyclin-dependent kinase inhibitor genes CDKN1A/p15, CDKN2C/p18, CDKN2B/p21). The patient underwent distal splenopancreatectomy and at the 4-month follow-up she showed complete remission of symptoms. Six months later, a thyroid nodule, suspected to be a malignant neoplasia, and two hyperfunctioning parathyroid glands were detected respectively by ultrasound with fine needle aspiration cytology and 99mTc-sestamibi scan with SPECT acquisition. Total thyroidectomy was performed, whereas selective parathyroidectomy was preferred to a more extensive procedure because the diagnosis of MEN1 was not supported by genetic analysis and intraoperative intact parathyroid hormone had revealed "adenoma-like" kinetics after the second parathyroid resection. Thirty-nine and 25 months after respectively the first and the second operation, the patient is well and shows no signs or symptoms of recurrence.

CONCLUSIONS

Despite well-defined diagnostic criteria and guidelines, diagnosis of MEN1 can still be challenging. When diagnosis is doubtful, appropriate management may be difficult to establish.

The 312N variant of the luteinizing hormone/choriogonadotropin receptor gene (LHCGR) confers up to 2·7-fold increased risk of polycystic ovary syndrome in a Sardinian population

OBJECTIVE

Polycystic ovary syndrome (PCOS) is a frequent condition, affecting about 15% of women of reproductive age. Because of its familial occurrence, a multifactorial model of susceptibility, including both genetic and environmental factors, has been proposed. However, the identification of genetic factors has been elusive.

DESIGN

Case-control study aimed at evaluating possible associations between functionally relevant variants of the luteinizing hormone/choriogonadotrophin receptor gene (LHCGR) and PCOS phenotype.

PATIENTS

A total of 198 PCOS and 187 non-PCOS women, aged 14-35 years, of Sardinian origin, were referred to the outpatient clinic of the Department of Obstetrics and Gynaecology of the University of Cagliari (Sardinia). PCOS diagnosis was based on the Rotterdam criteria.

MEASUREMENTS

We determined the genotype of ins18LQ, S291N and S312N variants at the LHCGR locus. Genotype was related to the presence or absence of PCOS and to several clinical and biochemical characteristics.

RESULTS

The presence of at least one 312N allele was strongly associated with PCOS risk (OR, 2·04; 95% CI, 1·32-3·14; χ(2) , 10·47; P = 0·001). 312N homozygosity was associated with a further risk increase (OR, 2·73; 95% CI, 1·25-5·95; χ(2) , 6·65; P = 0·01). The number of ins18LQ alleles was associated with LH serum levels in controls (χ(2) , 8·04, P = 0·017).

CONCLUSIONS

For the first time, we have identified a genetic variant that is strongly associated with PCOS in an isolated population. These results, if confirmed in other cohorts, may provide the opportunity to test the S312N genotype at the LHCGR locus in fertile women to assess the risk of PCOS. The avoidance of triggering factors like weight increase may improve the reproductive outcome of potentially at-risk subjects.

Multiple endocrine neoplasia type 2 syndromes (MEN 2): results from the ItaMEN network analysis on the prevalence of different genotypes and phenotypes

OBJECTIVE

Multiple endocrine neoplasia type 2 (MEN 2) is a genetic disease characterized by medullary thyroid carcinoma (MTC) associated (MEN 2A and 2B) or not familial MTC (FMTC) with other endocrine neoplasia due to germline RET gene mutations. The prevalence of these rare genetic diseases and their corresponding RET mutations are unknown due to the small size of the study population.

METHODS

We collected data on germline RET mutations of 250 families with hereditary MTC followed in 20 different Italian centres.

RESULTS AND CONCLUSIONS

The most frequent RET amino acid substitution was Val804Met (19.6%) followed by Cys634Arg (13.6%). A total of 40 different germline RET mutations were present. Six families (2.4%) were negative for germline RET mutations. The comparison of the prevalence of RET germline mutations in the present study with those published by other European studies showed a higher prevalence of Val804Met and Ser891Ala mutations and a lower prevalence of Leu790Phe and Tyr791Phe (P<0.0001). A statistically significant higher prevalence of mutations affecting non-cysteine codons was also found (P<0.0001). Furthermore, the phenotype data collection showed an unexpected higher prevalence of FMTC (57.6%) with respect to other MEN 2 syndromes (34% MEN 2A and 6.8% of MEN 2B). In conclusion, we observed a statistically significant different pattern of RET mutations in Italian MEN 2 families with respect to other European studies and a higher prevalence of FMTC phenotype. The different ethnic origins of the patients and the particular attention given to analysing apparently sporadic MTC for RET germline mutations may explain these findings.

A metabolic approach to the treatment of dilated cardiomyopathy in BIO T0-2 cardiomyopathic Syrian hamsters

Mechanisms underlying dilated cardiomyopathy (DCM) are poorly understood and effective therapy is still unavailable. The aim of this study was to examine the heart ultrastructure and dynamic of BIO T0-2 cardiomyopathic hamsters, an animal model of DCM, and to study in these animals, the effects of a co-formulation (HS12607) of propionyl-L-carnitine, coenzyme Q(10) and omega-3 fatty acids on cardiac mechanical parameters. Sarcomere length, Frank-Starling mechanism and force-frequency relations were studied on isolated ventricular papillary muscle from age-matched BIO F1B normal Syrian hamsters, BIO T0-2 control and BIO T0-2 HS12607-treated cardiomyopathic Syrian hamsters. At the optimum length to maximum active force, electron microscopy of left ventricular papillary muscle revealed that seven out of ten muscles studied showed shorter sarcomeres (1.20 +/- 0.29 microm), and the remaining three showed longer sarcomeres (2.80 +/- 0.13 microm), compared to those of normal hamsters (2.05 +/- 0.06 microm, n = 10). Severe alterations of the Frank-Starling mechanism, force-frequency relations and derivative parameters of contractile waves were also observed in vitro in the BIO T0-2 control hamsters. Long-term (8 weeks) treatment with HS12607 prevented alterations in sarcomere length in the BIO T0-2 cardiomyopathic hamsters; the Frank-Starling mechanism and force-frequency relations were also significantly (P < 0.05) improved in these hamsters. Therefore results of the present study strongly suggest the need for clinical studies on metabolic therapeutic intervention in the effort to stop the progression of dilated cardiomyopathy.

Astroglial in vivo response to cocaine in mouse dentate gyrus: a quantitative and qualitative analysis by confocal microscopy

Astrocytes have been proved to play a critical role in neuromodulation, neuroprotection, pH maintenance, axon guidance control during development, homeostasis preservation and blood brain barrier maintenance in the CNS (Kimmelberg and Norenberg, 1989). Quantitative changes in the expression of glial fibrillary acidic protein (GFAP), a cytoskeletal intermediate filament protein exclusively expressed in astrocytes (Bignami et al, 1972), have been observed after administration of alcohol (Framke, 1995), morphine (Beitner-Johnson et al., 1993), amphetamine and its derivates (Aguirre et al., 1999), cannabinoids (Suarez et al., 2000), nicotine (Janson and Moller, 1993), caffeine (Marret et al., 1993) and prenatal exposure to cocaine (Clarke et al., 1996; Nassogne et al., 1998). However, the general astrocytic response to drugs of abuse is still far from being defined. In the present study we examined the in vivo astroglial response to cocaine in mouse dentate gyrus, the hippocampus being a common target of neurotoxic agents (Walsh and Emerich, 1988) which has a prominent effect on learning and memory processes (Eichenbaum et al., 1992). Quantitative changes in immunoreactivity of GFAP were investigated 24 h after acute and repeated daily administration of intraperitoneal cocaine (20 mg/kg). Drug-induced morphological alterations and spatial distribution of astrocytes were evaluated by means of confocal microscope. The results show that, compared to control animals, GFAP expression is two-fold enhanced after a single cocaine injection, still significantly higher after seven consecutive daily administrations, but not statistically different after prolonged (14 days) drug treatment. Moreover, morphological and morphometric analyses reveal significant modifications in astrocytic numbers, cell size and shape complexity. These data demonstrate that in mouse dentate gyrus, cocaine exposure differently affects the expression of GFAP and induces strong changes in astrocytes proliferation rate and cell morphology. Taken together, our findings provide the first in vivo quantitative and qualitative evaluation of astrocytic response to several regimens of cocaine in adult animals brain.

Use of biocytin as neuroanatomic tracer in harvested human pancreas: a confocal laser scanning microscopy analysis

INTRODUCTION

To identify central neuroanatomic structure, biocytin labeling has recently been used. To date, there are no bibliographic references about the use of this molecule in investigations of the peripheral nervous system. In the present study, fresh, harvested human pancreas was used to evidence pancreatic innervations by biocytin.

AIM

To investigate for the first time pancreatic innervation in harvested pancreas from human multiorgan cadaveric donors.

METHODOLOGY

Biocytin labeling was used as a neuroanatomic tracing method, and confocal laser scanning microscopy was used for analysis for description by means of high-resolution images.

RESULTS

The application of biocytin-avidin staining in harvested human pancreas revealed numerous bundles of nervous fibers, intrapancreatic ganglia, few small solitary neurons, and a large number of positive supporting cells (glial-like cells). Biocytin appeared to pass through gap junctions between glial elements and neurons and among the neurons. In human pancreas, biocytin is rapidly transported in both anterograde and retrograde directions, with consequent visualization of fine details of pancreatic innervation morphology. Indeed, evidence of anterograde and retrograde transportation of biocytin has been demonstrated in the extensive labeling of pancreatic preganglionic and postganglionic fibers as well as a great number of chemical buds that wind through exocrine tissue or undetermined target cells.

CONCLUSION

To our knowledge, this is the first report of the successful use of biocytin in neuronal retrograde and anterograde labeling in the human peripheral nervous system.

Lipid metabolism and molecular changes in normal and atherosclerotic vessels

OBJECTIVES

a positive correlation between cholesterol esterification, acyl-CoA:cholesterol acyltransferase (ACAT), multidrug resistance (MDR1) gene expression and atherosclerotic lesions has been shown in human arteries. The objective of this study was to map the expression of MDR1, ACAT genes and the cholesteryl ester content in normal, atherosclerotic and varicose human vessels.

MATERIALS

vascular segments were obtained from seven cadaveric donors, 27 patients undergoing vascular surgery for severe atherosclerotic disease and 11 patients with saphenous vein varicosities.

METHODS

lipid analysis and RT-PCR of MDR1 and ACAT mRNAs were performed.

RESULTS

an increase in cholesteryl ester content and in ACAT and MDR1 expression was demonstrated in relation to the age in the arteries prone to atherosclerosis; this expression was maximal in arteries from symptomatic patients. In resistant arteries and in veins cholesteryl ester accumulation was rare and light, while ACAT and MDR1 expression was not related to the age of the subjects.

CONCLUSIONS

the results showed that an increase in MDR1 and ACAT expression may be responsible for the accumulation of cholesteryl esters as well as for cell growth rate acceleration in vessel sites prone to atherosclerosis.

Evidence of pituitary adenylate cyclase activating polypeptide (PACAP) in pancreatic islet cells by confocal microscopy

Several studies have shown that pituitary adenylate cyclase activating polypeptide (PACAP) stimulates at very low concentration insulin release from pancreatic beta cells. In addition, PACAP has been evidenced in pancreatic nervous fibers surrounding the islets, the core of the islet, and the capillaries. The aim of the present study was to demonstrate internalization of PACAP in pancreatic islet cells. Pancreatic islets were obtained from Wistar rat pancreata by modified Lacy's isolation method. The isolated islets were incubated in the presence of Fluo-PACAP 27, a fluorescent ligand specific for PACAP receptors. At the end of incubation the islets were fixed in paraformaldehyde and then observed by confocal microscope. Fluo-PACAP 27 was internalized into pancreatic islet cells, and this process was time- and temperature-dependent (37 degrees C). The fluorescent molecules converged toward the nucleus where an intense fluorescence was evidenced after 60 minutes. Incubation with phenyl arsine oxide as well as with PACAP 6-38, a receptor antagonist, prevented the internalization process. Further studies are required to explain the internalization process of PACAP 27 into the nucleus of pancreatic islet cells.

Opposite pattern of MDR1 and caveolin-1 gene expression in human atherosclerotic lesions and proliferating human smooth muscle cells

Cholesterol esterification and smooth muscle cell (SMC) proliferation are the crucial events in the development of atherosclerotic lesions. The objective of this study was to analyse cholesterol esterification and the expression of MDR1 (multidrug resistance), ACAT (acyl-CoA:cholesterol acyltransferase) and caveolin-1 genes in atherosclerotic and healthy vascular walls, in SMCs obtained from atherosclerotic lesions and saphenous veins. Results demonstrated higher levels of cholesterol esters, ACAT and MDR1 mRNAs and lower levels of caveolin-1 mRNA in atherosclerotic segments compared to adjacent serial sections of the same artery and the corresponding non-atherosclerotic arteries from cadaveric donors. SMCs isolated from atherosclerotic plaques manifested an increased capacity to esterify cholesterol and to grow at a faster rate than SMCs isolated from saphenous veins. In addition, when SMCs from atherosclerotic plaques were cultured in the presence of progesterone, a potent inhibitor of cholesterol esterification, significant growth suppression was observed. An increase in ACAT and MDR1 expression and a concomitant decrease in caveolin-1 expression were also observed in SMCs isolated from atherosclerotic arteries as early as 12 h after serum stimulation. An opposite pattern was found when SMCs were treated with progesterone. These findings support the idea that cholesterol esterification plays a role both in early atherogenesis and in clinical progression of advanced lesions and raise the possibility that the cholesterol ester pathway might directly modulate the proliferation of SMCs.

MDR1 gene expression in normal and atherosclerotic human arteries(1)

Recent studies have shown that a membrane p-glycoprotein, encoded by MDR1 gene, is involved in the transport of free cholesterol from the plasma membrane to endoplasmic reticulum, the site of cholesterol esterification by acyl-CoA:cholesterol acyltransferase (ACAT). Moreover, results deriving from our previous studies have shown that the rate of cell proliferation was positively correlated with cholesteryl ester levels as well as with ACAT and MDR1 gene expression. In this study, lipid content and the expression of the genes involved in cholesterol metabolism such as hydroxy-methylglutaryl coenzyme A reductase (HMGCoA-R), low-density lipoprotein receptor (LDL-R), ACAT and MDR1 have been investigated in control and atherosclerotic arteries. The results have shown that the levels of cholesteryl ester increase with the age of cadaveric donors in arteries prone to atherosclerosis (abdominal aorta, superficial femoral artery) and become predominant in advanced atherosclerotic lesions. The mRNA levels of ACAT and MDR1 showed the same age correlation, reaching the highest values in atherosclerotic specimens. These results suggest that MDR1 may be involved in the accumulation of intracellular cholesterol ester levels found in atherosclerotic lesions. Moreover, the levels of HMGCoA-R, LDL-R and ACAT gene expressions progressively increased with the age of cadaveric donors; conversely, in atherosclerotic specimens, the mRNA levels of HMGCoA-R and LDL-R drastically decreased while ACAT gene expression reached its maximum. These findings suggest a reactivation of normal homeostatic regulation of cholesterol in advanced and complicated lesions.

CREST staining of micronuclei from free-living rodents to detect environmental contamination in situ

In this work immunofluorescent antikinetochore (CREST) staining was used to analyse bone marrow micronuclei (MN) from free-living animals belonging to four different rodent species. Yellow-necked mice (Apodemus flavicollis) and bank voles (Clethrionomys glareolus) were trapped in the Czech Republic, Algerian mice (Mus spretus) in Spain and house mice (Mus musculus domesticus) in Italy. Animals were collected in areas displaying low or high environmental pollution in order to investigate the sensitivity of CREST analysis on bone marrow MN as a biomarker of environmental stress in situ. Differences in total MN frequencies between animals collected in control or contaminated areas were statistically significant for two species, whereas the differences in CREST+ MN were statistically significant for three species. Interestingly, the percentages of CREST+ MN in animals collected in the control areas were very low (3. 2-8.7%), suggesting that activities inducing alterations in the distribution of chromosomes are very rare in natural conditions. The increased frequencies of CREST+ MN observed in areas with high environmental impact indicate that activities producing loss of chromosomes at mitosis may be characteristic of anthropogenic environments such as industrial settlements around petrochemical factories. Our data suggest that the analysis of CREST+ MN may represent a sensitive end-point for the detection of environmental contamination by genotoxic xenobiotics, offering the advantage of providing information on the mechanism of action of environmental contaminants.

Evaluation of new small barium alginate microcapsules

Microencapsulation of islets of Langerhans has been proposed in order to prevent immune rejection and possible recurrence of autoimmune disease. This study introduces a fast simple one-step microencapsulation procedure which allows the production of small sized barium-alginate beads. The volume of the microcapsules produced was approximately that of the encapsulated islets. Consequently, the insulin kinetics and the oxygen diffusion were favoured, while the transplanted tissue volume was reduced. Electron microscopy and immunoisolating testing were performed to evaluate the molecular cut-off, the physical and chemical characteristics of these microcapsules. Immunohistochemical staining and perifusion experiments of microencapsulated pancreatic islets showed their viability after the encapsulation procedure as well as in vivo experiments. In fact, microencapsulated porcine islets were implanted intraperitoneally into streptozotocin-diabetic rats. The xenografts reversed the hyperglycemic state and functioned for a period ranging from 9 to 385 days. The low mannuronic acid concentration and the purity grade of the alginate, exerted a combined influence on the capsule biocompatibility as in vivo studies showed.

[Xenograft of pancreatic islets: preliminary results of a new immunoisolation method]

Results of clinical islet transplantation remain disappointing despite the advances in islet technology. Availability of human organs and control of rejection by adequate immunosuppressive therapy remain the unsolved problems. Transplantation of xenogeneic tissue enclosed in immuno-separating membranes without immunosuppressive drugs may be a solution. In the present study porcine pancreatic islets were isolated by semiautomated method and purified utilizing discontinuous Euroficoll gradients on IBM 2991 cell separator. The porcine pancreatic islets were encapsulated with a new one-step method utilizing a home-made droplet generator. Each microcapsule contained one or two islets and microcapsule diameter was approximately that of the islets. This condition allows an optimal diffusion of insulin, glucose, nutrients and oxygen. Consequently, perifusion experiments with encapsulated porcine islets revealed a typical biphasic pattern of insulin release as it was seen in unencapsulated controls. Human erythrocytes were encapsulated and incubated with serum containing hemolysins and complement. These experiments showed that the encapsulated erythrocytes were protected against the hemolytic activity of Ig G and complement fractions. In conclusion, this encapsulation procedure allows the production of a very thin barium alginate membrane around the islets with very little increase of the total volume of transplanted tissue.