Simple Trends in the Methylene and α‐Substituent Regions of NMR Spectra of Vinyl Polymers

Summary: Chemical shift trends in the methylene and α substituent regions of ¹³C NMR spectra of vinyl polymers have been analyzed in terms of a three‐state rotational isomeric states (RIS) model and the γ‐gauche effect. In this framework, it has been demonstrated that the three sequencing rules observed for poly(propylene) can also be expected to work for many other vinyl polymers. The first two rules, justified in terms of the conformational perturbability of stereosequences, turn out to be respected by a considerable number of NMR spectra. On the other hand, the same spectral data are in substantial disagreement with the third rule. An explanation is proposed for this breakdown.

Sketches of the three conformations expected for rotation on the two prochiral bonds flanking the methine carbon of a vinyl polymer.     

Sublingual immunotherapy for hazelnut food allergy: a randomized, double-blind, placebo-controlled study with a standardized hazelnut extract

BACKGROUND: Food allergy may be life-threatening, and patients affected need to receive accurate diagnoses and treatment. Hazelnut has often been implicated as responsible for allergic reactions, and trace quantities can induce systemic reactions. OBJECTIVE: The aim of this study was to evaluate the efficacy and tolerance of sublingual immunotherapy with a standardized hazelnut extract in patients allergic to hazelnut. METHODS: This was a randomized, double-blind, placebo-controlled study. Inclusion criteria were a history of hazelnut allergy and positive skin prick test and double-blind placebo-controlled food challenge results. Patients were then randomly assigned into 2 treatment groups (hazelnut immunotherapy or placebo). Efficacy was assessed by double-blind, placebo-controlled food challenge after 8 to 12 weeks of treatment. Blood samples were drawn for measurement of specific IgE, IgG(4), and serum cytokines before and after treatment. RESULTS: Twenty-three patients were enrolled and divided into 2 treatment groups. Twenty-two patients reached the planned maximum dose at 4 days. Systemic reactions were observed in only 0.2% of the total doses administered. Mean hazelnut quantity provoking objective symptoms increased from 2.29 g to 11.56 g (P = .02; active group) versus 3.49 g to 4.14 g (placebo; NS). Moreover, almost 50% of patients who underwent active treatment reached the highest dose (20 g), but only 9% in the placebo. Laboratory data showed an increase in IgG(4) and IL-10 levels after immunotherapy in only the active group. CONCLUSION: Our data confirm significant increases in tolerance to hazelnut after sublingual immunotherapy as assessed by double-blind, placebo-controlled food challenge, and good tolerance to this treatment.     

The HLA crossroad in tumor immunology

It is generally accepted that human and experimental tumor cells can lose major histocompatibility complex (MHC) class I molecules. These human leukocyte antigen (HLA) losses are detected when the primary tumor breaks the basal membrane, invades the surrounding tissues, and starts to metastasize. These altered HLA class I phenotypes probably constitute the major tumor escape mechanism facing anti-tumor T-cell mediated responses. Thus, it is important to characterize these phenotypes in clinical tumor samples, analyze the mechanism(s) responsible for them, and counsel patients before and during peptide anti-cancer immunotherapy. The present paper summarizes the most relevant altered HLA class I phenotypes found in human tumor samples, indicates their frequency, and outlines the mechanisms implicated. This review also points out that the natural killer (NK) escape mechanism of HLA class I deficient cancer cells is yet to be defined. Knowledge accumulated to date reveals that HLA class I molecules are an important crossroad in tumor immunology.     

Accuracy of staging in primary biliary cirrhosis.

AIMS: To evaluate sampling variability of liver biopsy in patients with primary biliary cirrhosis (PBC). METHODS: Sections from 50 PBC liver specimens obtained at transplantation were examined. The degree of fibrosis was assessed on a scale of 0-4 using two methods: (1) simulated needle biopsy in fields approximately the size of conventional needle biopsy; and (2) whole section scanning in areas with little and extensive fibrosis. RESULTS: Considerable variation in the range of stages of fibrosis was found when the whole section scanning method was used. Only 10 (20%) samples had a consistent degree of fibrosis in all sections scanned. By contrast, the same fibrosis stage was assigned in 30 (60%) specimens examined using the simulated needle biopsy method. When the results obtained by the two methods were compared, there was a discrepancy of one or two stages in 32 samples. This discrepancy was the result of discovering areas with a lesser degree of fibrosis in whole sections compared with the simulated needle biopsy specimens. CONCLUSION: There is considerable variation in the degree of fibrosis in the livers of patients with PBC, even when end stage specimens obtained at transplantation are examined. Consistent results were obtained when simulated needle biopsy specimens were examined. This, however, may be a reflection of the procedure applied when staging liver needle biopsy specimens, where the greatest degree of abnormality is used in determining the stage. The practice of staging of PBC in small needle biopsy specimens is valuable as long as the appearances are interpreted with caution, bearing in mind that there is considerable variability in the degree of fibrosis.     

In vivo activation of NK cells induces inhibition of lung colonization of H-2 positive and H-2 negative fibrosarcoma tumor clones

The role of different tilorone analogs in the abrogation of the metastatic spread of H-2 positive and H-2 negative tumor clones was studied. Pre-treatment of BALB/c mice with RMI 10,874DA compound completely abolished lung colonization of an H-2 negative (GR9.B9) MCA-induced fibrosarcoma clone in an experimental metastasis assay. This effect was also evident when clones were treated with other tilorone analogs (R11,567DA or R11,513DA). Other H-2 positive and H-2 negative chemically induced fibrosarcoma clones were also tested. The effect was not due to direct toxicity of the tilorone analog on tumor cells, but instead was dependent on NK cells; this was suggested by the finding that treatment of mice with anti-asialo GM₁ abrogated the effect of the tilorone analog (RMI 10,874DA compound). Interestingly, the inhibition of lung colonization after intravenous injection was again observed regardless of the H-2 phenotype of the tumor clones, and H-2⁺ and H-2^– clones were similarly inhibited.In vitro assays of NK sensitivity of tumor clones showed that lysis varied depending on the H-2 phenotype of tumor clones, indicating an absence of correlation betweenin vivo andin vitro results.     

High frequency of altered HLA class I phenotypes in invasive breast carcinomas

We studied 105 tumor samples obtained from patients diagnosed as having breast carcinomas for HLA class I and II (DR) antigen expression, using a panel of mAbs defining HLA-monomorphic, locus-specific and allele-specific determinants. Peripheral blood lymphocytes from patients were also typed for HLA alleles. The results indicated total HLA class I losses in 55 patients (52.3%), HLA-A locus losses in four patients (3.8%), HLA-B locus losses in eight patients (7.6%), and A, B, locus losses in 10 patients (9.5%). The remaining 28 patients whose tissues reacted positively with monomorphic- and locus-specific mAbs were tested for HLA allelic losses using several anti-HLA mAbs defining A2, A3, A9, B8, B12, etc. Of these 28 patients, 16 (57%) showed one or more losses of HLA reactivity. These results indicated that in 88.5% of patients we detected a particular HLA-altered tumor phenotype. The downregulation of HLA class I antigens in breast carcinomas may thus be more frequent than previously reported, and patients without HLA class I downregulation may be the exception rather than the rule. It cannot be ruled out that HLA alterations are present in some of the 12 patients with an apparently normal HLA phenotype, as some HLA alleles could not be studied because of the lack of appropriate mAbs. These HLA alterations could represent an important step associated with tumor invasion, conferring to the tumor cells the ability to escape from T-lymphocyte recognition.     

Establishment and characterization of a continuous human chondrosarcoma cell line,ch-2879: comparative histologic and genetic studies with its tumor of origin

Chondrosarcomas are malignant cartilage-forming tumors that represent the second most common malignant solid tumor of bone. These biologically poorly understood neoplasms vary considerably in clinical presentation and biologic behavior. Chemotherapy and radiation therapy are generally ineffective. Here we describe the establishment and characterization of a new human chondrosarcoma cell line named ch-2879, and we compare the cell line with its tumor of origin. The cell line was established from a recurrent grade 3 chondrosarcoma of the chest wall and characterized by growth kinetics and morphologic studies. Immunocytochemistry and RT-PCR were performed to examine the expression of cartilage-specific phenotypes. Genetic characterization was performed using cytogenetics, fluorescence in situ hybridization, flow cytometry, and molecular techniques for analysis of the genes implicated in cell cycle control, amplification of MDM2, CDK4, and Cyclin D1, and mutations in the p53 gene. ch-2879 cells were subcultured for more than 80 passages. They expressed vimentin, HNK-1, HBA-71, Ki-67, cyclin D1, Fli-1, S-100, p21, p27, and p53 and were negative for cytokeratin, EMA, p14, p16, MDM2, Rb, and c-erb-b2 antigens. Cytogenetically the recurrent tumor showed a hyperhaploid karyotype with clonal numerical and structural abnormalities. The sole structural abnormality was a chromosome derivative of a t(1;21) translocation. The cell line at passage 3 showed two populations: the hyperhaploid and an exactly duplicated, hypotriploid population. After the 18th passage, only the hypotriploid population was present. The cells expressed collagen 2. Molecular comparison of the primary and recurrent tumor evidenced an in vivo molecular change consisting of a deletion of 9p21 genes in the recurrence, probably caused by a selection process. Because of its gene expression profile, including expression of genes implicated in chondrogenesis in uncoated plastic dishes, this cell line may prove useful for cellular and molecular studies as well as studies of chondrosarcoma characterization and treatment.     

Developmental distribution of plasma membrane Ca2+-ATPase isoforms in chick cerebellum.

The plasma membrane Ca(2+)-ATPase (PMCA) is highly expressed in the nervous system, but little information is available about its implication in neuronal development. We have analyzed the expression and localization of different isoforms of PMCA in membrane vesicles and sections of chick cerebellum from embryonic day 10 to hatching. We found that the relative amount of each PMCA isoform and their spatiotemporal distribution in the cerebellum are directly linked to precise cellular types during the cerebellar maturation, even in a non-neural tissue as choroid plexus. Purkinje cells contain the highest diversity of PMCA isoforms of the cerebellar cortex since the moment of its morphogenesis. From embryonic day 15, the PMCA2 was highly expressed in the whole Purkinje cell, while PMCAs 1 and 3 had a more restricted distribution in the soma and dendritic branches, and these distributions were evolving according with cell maturation. Other cellular types seem to contain a specific combination of isoforms, but with a well-defined distribution pattern at late moments of development. Thus, PMCAs 1 and 3 were located in the soma of molecular layer interneurons, and only the PMCA2 was observed in granule cells at hatching. Furthermore, PMCA isoforms are also expressed in cellular compartments characterized by a high amount of synapses, suggesting a key role of these proteins in synaptogenesis and in the maturation of neuronal electrophysiological properties.