Cytokines and immunity in multiple sclerosis: the dual signal hypothesis

Multiple sclerosis (MS) is considered an immune-mediated disease of the central nervous system (CNS) sustained by a chronic inflammatory process leading to patchy demyelination and axonal loss. However, the inflammatory triggering event as well as the target of the pathogenic process in MS are still partially unknown. We report evidence that a 'local' inflammatory process occurring in the CNS (considered as a reaction of blood vessels in vascularized living tissue to a local injury leading to the accumulation of fluid and blood cells) along with a concomitant, but possibly unrelated, peripheral inflammatory event may trigger a CNS-specific autoimmune reaction cascade sustaining the MS pathogenesis. In the CNS, inflammatory mediators (mainly cytokines) act either as regulatory (i.e. activation of glial cells, shaping the autoimmune response) or effector molecules (i.e. myelinotoxicity, oligodendrotoxicity). In the periphery, inflammatory cytokines induce, in a bystander fashion, activation of monocytes and T cells. Among this latter cell population there are myelin-specific T cells belonging to the normal 'autoimmune' repertoire that home to the CNS where they may trigger the continuous recruitment of effector cells (macrophages) from the periphery. The concept that two concomitant, but possibly unrelated, inflammatory events, occurring in the CNS and in the periphery, represent the crucial elements sustaining MS, might reveal a more comprehensive view (dual signal hypothesis) of the entire etiopathogenic process underlying this disease.

Beta-endorphin concentrations in peripheral blood mononuclear cells of patients with multiple sclerosis: effects of treatment with interferon beta

CONTEXT

It has been reported that the opioid peptide beta-endorphin (BE) has immunosuppressive effects. Interferon beta (IFN-beta) is a well-established therapy for multiple sclerosis (MS), but immunological mechanisms underlying its beneficial effects in MS are partially undefined.

OBJECTIVES

To determine BE levels in peripheral blood mononuclear cells (PBMCs) of patients with relapsing-remitting MS during different phases of disease activity and the possible modulating effects of IFN-beta treatment on PBMC BE synthesis in patients with MS.

DESIGN

We measured BE levels in blood samples collected from 6 patients with MS who had not experienced clinical changes during the previous 3 months (patients with stable MS) and from 7 patients with MS during a clinical relapse. We also surveyed BE levels in PBMC samples from 8 patients with MS before treatment and for 6 months after the beginning of IFN-beta administration. The control group was 13 healthy subjects.

RESULTS

Low PBMC BE levels were detected in patients with stable MS and in those entering IFN-beta treatment compared with control subjects. Increased BE concentrations were observed in MS patients experiencing a clinical relapse compared with patients with stable MS. During IFN-beta treatment, the levels of BE in PBMC samples from patients with MS increased significantly (after 1 month, P =.02; after 3 months, P =.007; and after 6 months, P =.16).

CONCLUSIONS

A reduction of BE levels was present in patients with clinically inactive MS. Treatment with IFN-beta seems to induce an increase of this opioid in PBMCs of MS patients. The increase of BE concentration during a clinical relapse may represent a possible control mechanism aimed at counterbalancing the inflammatory phase of the disease. Arch Neurol. 2000;57:1178-1181

Principles of diagnosis and treatment of high-caries-risk subjects

The aim of this article is to highlight the main goals and to describe the clinical impact of the procedures used for the identification of high-caries-risk subjects. The techniques for the correction of caries risk level and their influence on restorative treatment are also described to enable the dental team to offer patients the most appropriate and successful treatment, and to meet an up-to-date and high-quality dental care standard.

Pulmonary pathology of Erdheim-Chester disease

Erdheim-Chester disease (ECD) is a rare non-Langerhans' cell histiocytosis that may present with pulmonary symptoms. The condition seems to be nonfamilial and typically affects middle-aged adults. Radiographic and pathologic changes in the long bones are diagnostic, but patients often present with extraskeletal manifestations. Advanced pulmonary lesions are associated with extensive fibrosis that may lead to cardiorespiratory failure. The clinical, radiologic, and pathologic features of six patients with ECD with lung involvement are presented. The patients were three men and three women (mean age, 57). Five presented with progressive dyspnea, and one presented with diabetes insipidus. Open-lung biopsies showed histiocytic infiltrates in a lymphangitic pattern with associated fibrosis and lymphoplasmacytic inflammatory infiltrates. The histiocytes did not stain with periodic acid-Schiff. Immunoperoxidase studies performed on specimens from five of six patients showed that the histiocytes were positive for CD68 and Factor XIIIa and negative for CD1a. Specimens from two patients exhibited immunoreactivity for S-100 protein. Electron microscopy studies performed on specimens from two patients showed phagocytic lysosomes but no Birbeck granules. Clinical follow-up of up to 16 years was available. At the end of that time, five patients were dead of complications related to their disease; one patient remains alive 4 years after diagnosis but with severe respiratory compromise. ECD is a rare non-Langerhans' cell histiocytosis that may present as interstitial lung disease and resemble other pulmonary conditions, particularly usual interstitial pneumonitis and pulmonary Langerhans' cell histiocytosis. Recognition of this entity will allow better assessment of its true incidence, therapeutic options, and prognosis.

Cultivatable microbial biodiversity: gnawing at the Gordian knot

Rapid and inexpensive sorting of bacterial isolates may be achieved using Fourier transform infrared spectroscopy (FT-IR), a method that has hitherto been applied to identification and classification. The comprehensive characterization of environmental samples requires the isolation of large numbers of isolates using different growth media and growth conditions. In such cases, sorting the isolates is critical before isolates are subjected to more detailed studies. Using FT-IR, isolates are grown under standardized conditions, and 100 strains can be tested within less than 8 h. Chemotaxonomic and molecular characterization of members of clusters emerging from FT-IR analysis either at a level of spectral distance values below 20-30 (analysis of region 600-800 cm(-1), average linkage algorithm) or at spectral heterogeneity values below 75 (regions 1,200-900, 3,000-2,798 and 901-698, scaling to first region, Ward's algorithm) reveals great similarities in fatty acids and 16S rDNA sequences. As judged from riboprinting analyses and fatty acid analyses, FT-IR analysis is able to unravel intraspecific subclustering. The example used in this study of 100 isolates from a mat system, Lake Fryxell, Dry Valleys, Antarctica, selected from a larger number of isolates, picked mainly on the basis of colony pigmentation and form, reveals the utility of the method for identifying the number of putative species quickly. The method described is able to select strains rapidly that represent clusters at the specific and intraspecific level for subsequent characterization.

Divergent differentiation in neuroendocrine lung tumors

The classification of neuroendocrine (NE) lung tumors has been revised in the 1999 World Health Organization (WHO) classification of lung tumors, allowing sharp morphological definition of typical versus atypical carcinoids, and atypical carcinoids versus large cell neuroendocrine carcinoma (LCNEC), a newly described class of high-grade NE lung tumors which differs from small-cell lung cancer by a large-cell phenotype. Divergent differentiation accounts for the high frequency of glandular differentiation with mucin production, and ultrastructural features in carcinoids and LCNEC, and low frequency of squamous differentiation in both LCNEC and SCLC. Specific NE markers (chromogranin, synaptophysin, neural cell adhesion molecule) and epithelial markers consistently negative in neuroendocrine components (cytokeratins 1, 5, 10, 14; epidermal growth factor (EGF)-receptor, human leukocyte antigen beta 2 (HLA-beta2) microglobuline) help to recognize divergent differentiation in NE tumors. At morphological level, divergent differentiation in NE tumors is recognized in WHO classification as variants: combined SCLC and combined LCNEC. The derivation of all lung tumors from a common endodermal stem cell and adoption of amine precursor uptake and decarboxylation properties by this endodermal stem cell explains divergent differentiation in NE lung tumors and the occurrence of NE subsets in NSCLC.

MEN1 gene mutation analysis of high-grade neuroendocrine lung carcinoma

Neuroendocrine tumors of the lung consist of a spectrum of neoplasms, including typical carcinoids, atypical carcinoids, large-cell neuroendocrine carcinomas (LCNEC), and small-cell lung carcinomas (SCLC). We previously reported frequent inactivation of the gene responsible for multiple endocrine neoplasia type 1 (MEN1) in both typical and atypical carcinoid tumors. In the present study, we extend the analysis of human NE lung tumors to include 9 primary SCLCs, 36 SCLC cell lines, and 13 primary LCNECs for MEN1 gene inactivation. In SCLC, loss of heterozygosity (LOH) at the MEN1 gene on chromosome band 11q13 was detected in one primary tumor and two cell lines. The coding sequence and splice junctions of the MEN1 gene were screened for mutations in all 44 tumors and cell lines, and no mutations were detected. Northern blot analysis of 13 SCLC cell lines showed the MEN1 transcript to be present and of normal size. In LCNECs, a somatic frameshift in the MEN1 gene (1226delC) was found in one of 13 tumors, representing the first mutation observed outside the spectrum of neoplasms associated with MEN1. Interestingly, neither a deletion nor a mutation was detected in the other allele, and wild-type mRNA sequence was expressed in the tumor, suggesting that the MEN1 gene was not inactivated by a conventional two-hit mechanism. The data support the hypothesis that SCLC and lung carcinoids develop via distinct molecular pathways; however, further investigation is necessary to determine the significance of the MEN1 gene mutation observed in a single case of LCNEC. Published 2000 Wiley-Liss, Inc.

NCAM (neural cell adhesion molecules) expression in malignant mesotheliomas

Neural cell adhesion molecules (NCAM) are adhesion molecules expressed by neural and neuroendocrine tumors and a few biphasic tumors such as synovialosarcomas and breast phyllode tumors. To investigate NCAM expression in mesotheliomas, we studied 26 cases of epithelioid (n = 12), biphasic (n = 11), and sarcomatoid (n = 3) malignant mesotheliomas (MM), in comparison with normal mesothelium, and 50 primary non-small cell lung carcinomas (NSCLC) (25 adenocarcinomas [ADC] and 25 squamous cell carcinomas [SCC]), using electron microscopy as a gold standard for recognition of MM. NCAM reactivity using 123C3 antibody was compared with that of NE markers such as chromogranin A and synaptophysin. Although normal mesothelium remains negative, NCAM was expressed in 19 of 26 MM (73%) with a membranous staining on frozen or paraffin sections. In 6 of 12 epithelioid MM, the tumor cells expressed NCAM, whereas in 5 cases stromal fibroblasts showed a strong but focal staining. In 11 biphasic MM, 4 presented an NCAM reactivity of both epithelioid and spindle cell components, whereas in 7, only fusiform component was NCAM positive. Two of 3 sarcomatoid MM showed an NCAM expression. Chromogranin expression was never seen, whereas synaptophysin was noticed in 2 cases. No case of NSCLC showed membranous 123C3 staining, whereas 2 ADC weakly expressed synaptophysin. We conclude that NCAM expression in MM is reminiscent of its expression in mesoderm during fetal life and consistent with that reported in other biphasic tumors. These data show that NCAM expression occurs in 73% of MM, highly exceeding that observed in lung cancer.

Expression of vascular endothelial growth factor (VEGF) and its two receptors (VEGF-R1-Flt1 and VEGF-R2-Flk1/KDR) in non-small cell lung carcinomas (NSCLCs): correlation with angiogenesis and survival

The formation of new vessels (angiogenesis) is essential for primary tumour growth and metastasis and is induced by several angiogenic factors, including vascular endothelial growth factor (VEGF). The microvascular density (MVD) in tumours was assessed and the expression of VEGF and its receptors VEGF-R1-Flt1 and VEGF-R2-KDR/Flk1 was investigated in the different cellular compartments in vivo, in order to establish their interrelationship and their prognostic influence. Immunohistochemical study of 69 stage I-II non-small cell lung carcinomas (NSCLCs) was performed on paraffin sections with CD34 antibody to estimate MVD, using a Chalkley eye-piece graticule and VEGF, VEGF-R1, and VEGF-R2 antibodies. There was strong expression of VEGF and its receptors in tumour cells, endothelial cells, and stromal fibroblasts. In tumour cells, the level of VEGF was correlated with that of VEGF-R1 ( p = 0. 018) but not that of VEGF-R2. In fibroblasts, high expression of VEGF was correlated with that of VEGF-R1 ( p = 0.0001) and VEGF-R2 ( p = 0.0001). In endothelial cells, expression of VEGF was correlated with that of VEGF-R1 ( p < 0.0001) and VEGF-R2 ( p = 0.04). The level of VEGF in fibroblasts was correlated with that of VEGF-R1 ( p = 0.0028) and VEGF-R2 ( p = 0.01) in endothelial cells. There was no correlation between the level of MVD and that of VEGF or VEGF-R1 or VEGF-R2. Neither the level of MVD, nor the level of expression of VEGF and VEGF receptors in any compartment influenced the patient's survival. In conclusion, although angiogenesis is essential for tumour growth, this study failed to demonstrate that MVD, VEGF, VEGF-R1, and VEGF-R2 are prognostic markers for stage I-II NSCLC. VEGF, however, might act as a direct autocrine growth factor for tumour cells via VEGF-R1 and angiogenesis could be promoted in a paracrine loop, where VEGF is produced by fibroblasts and tumour cells and then binds to endothelial cells via induced VEGF receptors. VEGF and its receptors thus appear as relevant therapeutic targets in NSCLC.

Semaphorin SEMA3F localization in malignant human lung and cell lines: A suggested role in cell adhesion and cell migration

Semaphorins/collapsins are a family of secreted and membrane-associated proteins involved in nerve growth cone migration. However, some are expressed widely in adult tissues suggesting additional functions. SEMA3F/H.SemaIV was previously isolated from a 3p21.3 homozygous deletion region in human lung cancer. We studied SEMA3F cellular localization using our previously characterized anti-SEMA3F antibody. In normal lung, SEMA3F was found in all epithelial cells at the cytoplasmic membrane and, to a lesser extent, in the cytoplasm. In lung tumors, the localization was predominantly cytoplasmic, and the levels were comparatively reduced. In non-small-cell lung carcinomas, low levels correlated with higher stage. In all tumors, an exclusive cytoplasmic localization of SEMA3F correlated with high levels of vascular endothelial growth factor and was related to the grade and aggressiveness. This suggests that vascular endothelial growth factor might compete with SEMA3F for binding to their common receptors, neuropilin-1 and -2 and might contribute to SEMA3F delocalization and deregulation in lung tumor. In parallel studies, SEMA3F distribution was examined in cell cultures by confocal microscopy. Marked staining was observed in pseudopods and in the leading edge or ruffling membranes of lamellipods or cellular protrusions in motile cells. SEMA3F was also observed at the interface of adjacent interacting cells suggesting a role in cell motility and cell adhesion.

Caries-preventive effect of topical amine fluoride in children with high and low salivary levels of mutans streptococci

The aim of the study was to assess the relationship between the salivary mutans streptococci (SMS) level and the effectiveness of a preventive intervention based on a biannual application of an amine fluoride solution (AmF). A total of 284 schoolchildren aged 6 years were recruited from eleven classes of a primary school in Milan and randomly assigned to an experimental (A) and a control group (B). SMS counts were obtained at baseline and caries incidence data (diseased, missing, filled teeth, DMFT) were recorded every 6 months for 5 years. The participants of the experimental group received application of an AmF 1% F(-) solution twice a year on the enamel surfaces of the first permanent molars for 5 years. Control group subjects received application of a placebo solution twice a year on the enamel surfaces of the first molars for the same period. The mean DMFT in the experimental and control groups were 0.56 and 0.22, respectively, at the beginning and 1.14 and 2.06 after 5 years. SMS data allowed children to be classified into low- (0-10(5) CFU/ml of saliva) and high- (>10(5) CFU/ml of saliva) SMS subjects. Survival analysis, performed on the first molar data split by SMS group, showed a significantly higher caries reduction in low-SMS experimental group subjects compared to low-SMS control group subjects after 5 years. No significant differences were found between the two high-SMS experimental and control groups. These findings indicate that the preventive effects of the treatment were significantly lower in subjects who had high SMS. It is concluded that the effectiveness of a simple and economical topical fluoride intervention applicable at a community level is significantly influenced by the SMS level of the subjects involved. Simple AmF preventive interventions, applied on low-SMS subjects, can give significant results in terms of caries reduction.

Comparison of chromosomal imbalances in neuroendocrine and non-small-cell lung carcinomas

Lung carcinomas are represented by non-small-cell lung carcinomas (NSCLC) and neuroendocrine carcinomas (NE) which differ in their clinical presentation and prognosis. We used comparative genomic hybridization (CGH) to characterize and compare the chromosomal pattern of 11 NSCLC and 11 high-grade NE lung carcinomas. Overall, the total number of aberrations was higher in NSCLC than in high-grade NE lung tumors (p < 0.05) and gains predominated over losses in NSCLC (p < 0.0003). Gains common to both lung tumor phenotypes were detected in 1p, 1q, 3q, 5p, 6p, 8q, 12, 17q, 19p, 19q, 20p, 20q, and X, whereas common losses were found in 2q, 3p, 4p, 4q, 5q, 8p, 9p, 10p, 11p, 11q, 13q, and 17p. Major gains on 18q and losses on 2p and 16q were exclusively detected in high-grade NE lung tumors. On the other hand, major gains on 2p and 15q and losses on 21q were found only in NSCLC. Furthermore, gains within 22q11-q12 and 7p12-p15 were associated with NSCLC (p < 0.05). The differences in the pattern and distribution of genetic changes observed in NSCLC as opposed to high-grade NE lung carcinomas suggest the existence of distinct tumorigenic pathways between these two major classes of lung tumors.

Proliferation, C-myc, and cyclin D1 expression in diffuse alveolar damage: potential roles in pathogenesis and implications for prognosis

In this study we compared expression of DNA topoisomerase IIalpha, a marker of cellular proliferation, c-myc, and cyclin D1 in lung biopsy specimens showing diffuse alveolar damage (DAD) with control lung tissues. We subsequently correlated DNA topoisomerase IIalpha, c-myc, and cyclin D1 expression with survival. We hypothesized that poor outcome may correlate with a higher proliferation index, and that c-myc and cyclin D1 activation are potentially important regulators of both proliferation and apoptosis in DAD. Immnuohistochemical stains for c-myc, cyclin D1, and DNA topoisomerase IIalpha were performed on 10 cases of DAD (15 cases for DNA topoisomerase IIalpha) and 10 control lungs. A proliferation index for each case was calculated by dividing the number of nuclei expressing DNA topoisomerase IIalpha by the total number of nuclei counted. The percentages of alveolar pneumocytes and interstitial cells staining positively for c-myc and cyclin D1 were estimated. The average proliferation index (DNA topoisomerase IIalpha index) in DAD (0.16 +/- 0.06, n = 15) was significantly greater than in control lungs (0.00 +/- 0.01, n = 10) (P < .0001). The average proliferation index of patients with DAD who died of respiratory failure (0.18 +/- 0.05, n = 9) was significantly greater than the average proliferation index of patients whose respiratory disease resolved or stabilized (0.11 +/- 0.05, n = 5) (P < .03). Expression of c-myc in alveolar pneumocytes and interstitial cells was more intense and slightly more widespread in cases of DAD compared with control lungs. In 9 of 10 cases of DAD, cyclin D1 expression was present in up to 30% of alveolar pneumocytes and up to 10% of interstitial cells. No staining for cyclin D1 was present in control lungs. These results show that the proliferation index in DAD potentially correlates with patient survival. Furthermore, enhanced expression of c-myc and cyclin D1 may contribute to dysregulation of cellular proliferation and apoptosis observed in DAD.

Expression of vascular endothelial growth factor (VEGF) and its two receptors (VEGF-R1-Flt1 and VEGF-R2-Flk1/KDR) in non-small cell lung carcinomas (NSCLCs): correlation with angiogenesis and survival

The formation of new vessels (angiogenesis) is essential for primary tumour growth and metastasis and is induced by several angiogenic factors, including vascular endothelial growth factor (VEGF). The microvascular density (MVD) in tumours was assessed and the expression of VEGF and its receptors VEGF-R1-Flt1 and VEGF-R2-KDR/Flk1 was investigated in the different cellular compartments in vivo, in order to establish their interrelationship and their prognostic influence. Immunohistochemical study of 69 stage I-II non-small cell lung carcinomas (NSCLCs) was performed on paraffin sections with CD34 antibody to estimate MVD, using a Chalkley eye-piece graticule and VEGF, VEGF-R1, and VEGF-R2 antibodies. There was strong expression of VEGF and its receptors in tumour cells, endothelial cells, and stromal fibroblasts. In tumour cells, the level of VEGF was correlated with that of VEGF-R1 ( p = 0. 018) but not that of VEGF-R2. In fibroblasts, high expression of VEGF was correlated with that of VEGF-R1 ( p = 0.0001) and VEGF-R2 ( p = 0.0001). In endothelial cells, expression of VEGF was correlated with that of VEGF-R1 ( p < 0.0001) and VEGF-R2 ( p = 0.04). The level of VEGF in fibroblasts was correlated with that of VEGF-R1 ( p = 0.0028) and VEGF-R2 ( p = 0.01) in endothelial cells. There was no correlation between the level of MVD and that of VEGF or VEGF-R1 or VEGF-R2. Neither the level of MVD, nor the level of expression of VEGF and VEGF receptors in any compartment influenced the patient's survival. In conclusion, although angiogenesis is essential for tumour growth, this study failed to demonstrate that MVD, VEGF, VEGF-R1, and VEGF-R2 are prognostic markers for stage I-II NSCLC. VEGF, however, might act as a direct autocrine growth factor for tumour cells via VEGF-R1 and angiogenesis could be promoted in a paracrine loop, where VEGF is produced by fibroblasts and tumour cells and then binds to endothelial cells via induced VEGF receptors. VEGF and its receptors thus appear as relevant therapeutic targets in NSCLC.

Alterations of expression of Rb, p16(INK4A) and cyclin D1 in non-small cell lung carcinoma and their clinical significance

Inactivation of the Rb pathway in non-small cell lung carcinoma (NSCLC) occurs mostly through inactivation of the cyclin-dependent kinase inhibitor p16(INK4A) and/or up-regulation of cyclin D1. In order to assess the frequency and the prognostic value of these abnormalities in NSCLC, immunohistochemical analysis of Rb, p16(INK4), and cyclin D1 has been performed on 168 cases of NSCLC including 77 squamous cell carcinomas, 43 adenocarcinomas, and 48 basaloid carcinomas. The reduced survival rate of basaloid carcinoma (stage I-II) compared with other histological types of NSCLC was confirmed (p = 0.008). Loss of protein expression of Rb and p16(INK4A) was observed in 12 per cent and 58 per cent of NSCLC cases respectively and cyclin D1 overexpression in 43 per cent. There was an inverse correlation between Rb and p16 expression ( p < 0.0001) and a direct correlation between Rb and cyclin D1 expression ( p = 0.0007). In univariate analysis, Rb-negative adenocarcinomas at stages I-II had a significantly shorter survival than Rb-positive cases ( p = 0.04) and stages I-II p16-positive cases had a shorter survival than p16-negative cases ( p = 0.02), which was more significant in basaloid carcinoma ( p = 0.003). p16 status retained its influence on survival in multivariate analysis at stage I-II for all cases ( p = 0.01) and for basaloid carcinoma ( p = 0.005). Cyclin D1 overexpression did not influence survival. Combined Rb/p16/cyclin D1 phenotypes in univariate analysis showed a shorter survival for Rb-negative/p16-positive/cyclin D1-negative tumours ( p = 0.002). These results, linked to previous data, indicate that the Rb pathway of G1 arrest is initially disrupted in the vast majority of NSCLCs (83 per cent), but could not confirm an unfavourable role for each individual event (p16(INK4A) loss or cyclin D1 up-regulation) in prognosis.

Expression of plasminogen activator inhibitors 1 and 2 in lung cancer and their role in tumor progression

The plasminogen activator cascade initiated by urokinase type plasminogen activator (u-PA) is involved in extracellular matrix degradation during the tumor invasion process. The plasminogen activator inhibitors 1 (PAI-1) and 2 (PAI-2) are two specific inhibitors of u-PA. We hypothesized that the balance between u-PA and its two inhibitors could be disrupted to favor plasminogen activation during lung cancer progression. Using immunohistochemistry, we analyzed the pattern of expression of u-PA, PAI-1, and PAI-2 in non-small cell lung carcinomas (NSCLC) and neuroendocrine (NE) lung tumors. u-PA and PAI-1 were both detected in stromal fibroblasts and in tumor cells. In 84 NSCLCs, their epithelial expression was strongly correlated and linked to the presence of node metastasis (P = 0.008), whereas their coexpression in fibroblasts was associated with larger tumor size (P = 0.04) and advanced stages (P = 0.009). In 72 NE tumors, u-PA and PAI-1 were more frequently expressed in fibroblasts in high-grade NE tumors (SCLC and large cell NE tumors) than in low- and intermediate-grade tumors (typical and atypical carcinoids). Comparison of in situ hybridization and immunohistochemistry in 14 cases showed that PAI-1 was consistently expressed by stromal fibroblasts, although the protein was also localized in tumor cells. In contrast, the expression of PAI-2 was restricted to fibroblasts and correlated with the absence of nodal involvement (P = 0.005). Considering NE tumors, the frequency of PAI-2 expression decreased along the NE spectrum from typical carcinoids to SCLCs. These data suggest that PAI-lacts in synergy with u-PA to favor tumor invasion process and connotes aggressivity, in contrast with PAI-2, which may block u-PA-mediated proteolysis and is inversely correlated with tumor progression.

In vivo delivery to tumors of DNA complexed with linear polyethylenimine

Synthetic gene delivery vectors have shown promise in several organs, including brain and lung. Tumor cell targeting, however, is still hindered by their low efficacy. A linear polyethylenimine (L-PEI, Exgen 500) was found to be effective in vivo. Our first attempts to use L-PEI for intratumoral gene delivery were not successful, presumably because of poor diffusion of the complexes within the tumor mass after injection with a syringe. Here we show that L-PEI-mediated transfection can be strongly enhanced when the complexes are delivered slowly into a solid tumor mass, using a micropump. Furthermore, L-PE/DNA complexes actively transfect pseudocystic tumor cells when injected into the cyst cavity. In both cases L-PEI induced a significant and long-lasting (> or =15 days) expression of the reporter gene. Finally, even though systemic delivery of L-PEI/DNA complexes leads to high levels of expression in the lung, this method is not adapted for transfection of subcutaneous tumors implanted in the thigh nor for transfection of lung metastases. Altogether, these results show that L-PEI has promising features for transfection of tumor cells, provided that the mode of delivery is adapted.

Ergoline derivatives: receptor affinity and selectivity

Ergot comprises a group of indole alkaloids which are predominantly found in various species of the ascomycete Claviceps. In pharmacopoeias, the sclerotia of Claviceps purpurea (Fr.) Tulasne parasitizing on rye, Secale cereale L., are designed as ergot or Secale cornutum. Now, the term ergot is used in a broader sense to describe the sclerotia of various Claviceps species growing on different host plants or their saprophytic mycelia. Due to their many fascinating features, there is a continuing and extensive interest in these secondary metabolites. Thus, the chemistry of ergot alkaloids and derivatives has presented many challenges to organic chemists. The ergot alkaloids and derivatives have attracted great interest for their broad spectrum of pharmacological action that includes central, neurohumoral and peripheral effects. These are mainly responses mediated by noradrenaline, serotonin, or dopamine receptors. No other group of natural products exhibits such a wide spectrum of biological action. For this reason, ergot has been termed a veritable treasure house of pharmacological constituents'. Moreover, ergot alkaloids have been an important stimulus in the development of new drugs by providing structural prototypes of molecules with pronounced pharmacological activities. This concise review, moving from the experience of our group in Pharmacia & Upjohn, will briefly mention the most representative ergoline derivatives featured in the literature. Our work in this field originated compounds with quite different pharmacological activities. In fact, by continuous modification of the same main template structure, the ergoline skeleton, it ultimately led to the development of new dopaminergic agents and to the identification of new series of serotonergic agents.

Graves-Basedow disease goiter: a model of Bax-Bcl2 regulated apoptosis

This study demonstrates the involvement of a Bax-Bcl2-dependent apoptotic process in Graves-Basedow thyroid disease, a pathological condition known for its spontaneously oscillating evolution. A continuous series of 86 cases of surgically treated Graves' thyroid was evaluated for apoptotic cell content identified by histological criteria and confirmed by terminal desoxynucleotidyl transferase-mediated desoxyuridine triphosphate nick end-labeling (TUNEL). A significant correlation was found between tissue features of Graves' disease (epithelial hyperplasia, cellular hypertrophy, colloid content) and the amount of apoptotic cells. No correlation was found with lymphocytic infiltrates. Significantly, 11 cases (about 12% of the series) with high-level apoptosis displayed the typical features of active Graves' disease over all tissue sections. In contrast, cases with no detectable apoptosis exhibited regressive tissue features of Graves' disease. An intermediate group of cases was characterized by tissue heterogeneity with hyperactive foci, rich in apoptosis, alternating with regressive areas lacking apoptosis. In this group the participation of apoptosis to the remodeling of Graves' thyroid parenchyma, in a tight balance with cell proliferation, was best illustrated. Moreover, the thyroid follicle by accumulating apoptotic cells and bodies, allowed a tentative chronological ordering of apoptosis steps in correlation with Bax-Bcl2 tissue distribution and cellular pattern. Our observations suggest that the initiation of apoptosis corresponds to a loss of cellular cohesion, a drop in Bcl2 expression, and a delocalization of Bax from a putative Golgi storage location to a mitochondrial distribution.

Toxoplasma gondii: role of the phosphatidylcholine-specific phospholipase C during cell invasion and intracellular development

The effect of D609, a specific inhibitor of phosphatidylcholine-specific phospholipase C, was investigated on cyst development of the Prugniaud strain of Toxoplasma gondii in vitro. Following treatment with the inhibitor 24 h after cell infection, cyst development was affected as assessed by staining with the bradyzoite-specific mAb CC2: the CC2-reactive antigen was shown to be differently located (in the wall versus the matrix under control conditions). This correlated with a decrease in parasite multiplication induced by D609. Pretreatment of the parasites with D609 inhibited their entry into the host cells, whereas pretreatment of the host cells enhanced the intracellular multiplication of the para sites, without any effect on cell invasion or cyst formation. Our results suggest a crucial role for phosphatidylcholine-specific phospholipase C in the pathophysiology of toxoplasmosis.

Salivary mutans streptococci and lactobacilli in 9- and 13-year-old Italian schoolchildren and the relation to oral health

The prevalence and levels of mutans streptococci (MS) and lactobacilli (LB) in saliva and its possible correlation with dental caries and periodontal conditions was investigated in 473 Italian schoolchildren, 9 and 13 years of age. A clinical examination and sampling of stimulated whole saliva was carried out in the school and oral health was assessed as DMFT and CPITN using the WHO criteria. The saliva samples were frozen in liquid nitrogen and after thawing, cultivated on selective media. To test the influence of cryopreservation, fresh samples from 20 subjects were cultivated. Thirty-five percent of the children were caries-free with a mean DMFT of 1.9 at the age of 13. The majority exhibited healthy periodontal conditions. Salivary MS and LB were identified in 52% and 21% of the children, respectively. The prevalence of MS was higher among the 13-year-olds than the 9-year-olds while no such difference was found regarding LB. There was a statistically positive relationship (P < 0.01) between the levels of MS and LB and both were significantly correlated to caries (P < 0.01). The correlation coefficient of microbial recovery between frozen and unfrozen samples was 0.99. In conclusion, the data provided cross-sectional information of a clear positive relationship between selected micro-organisms in saliva and caries in 9- and 13-year-old children in spite of a relatively low prevalence of the disease. The findings are discussed in a risk selection perspective.

TE671 cell-based ELISA for anti-acetylcholine receptor antibody determination in myasthenia gravis

BACKGROUND

Acetylcholine receptor (AChR) from human muscles is the antigen used currently in radioimmunoprecipitation assays (RIPAs) for the determination of anti-AChR antibodies in the diagnosis of myasthenia gravis (MG). Our aim was to develop and validate an ELISA using TE671 cells as the source of AChR.

METHODS

After TE671 cell homogenization, the crude AChR extract was used for plate coating. Anti-AChR antibodies were determined in 207 MG patients and in 77 controls.

RESULTS

The mean intra- and interassay CVs (for two samples with different anti-AChR antibody concentrations) were 9.7% and 15.7%, respectively. Test sensitivity and specificity, for generalized MG, were 79.5% (95% confidence interval, 72.8-85.0%) and 96.1% (89.0-99.1%). The detection limit was 2 nmol/L. Anti-AChR antibody concentrations from 53 MG patients, as tested with our ELISA, showed good agreement with an RIPA with a mean difference (SD) of 1.0 (5.6) nmol/L.

CONCLUSION

Our ELISA is a simple screening test for the diagnosis of MG and enables rapid and inexpensive patient follow-up.