Analysis of CDKN1A polymorphisms: markers of cancer susceptibility?

The CDKN1A (TP21) gene encodes a 21-kD protein that is a critical downstream mediator of wild-type TP53 and an important regulator of the cell cycle. Failure in the function of this gene would be expected to result in abnormal cell proliferation and transformation. Tumor-associated mutations of the coding region of the TP21 are rare. On the other hand, some TP21 polymorphisms have been identified and characterized by single base substitutions. In the present study, we investigated the potential role of TP21 gene polymorphisms in skin, head, and neck tumorigenesis. A total of 261 samples were examined by polymerase chain reaction single-strand conformational analysis, and one mutation at codon 31 and four polymorphisms in exons 2 (codon 55) and 3 [nucleotide (nt)590] and in promoter region (nt2298) were identified. In conclusion, this investigation confirmed the rarity of mutations in this gene, arguing against a role for TP21 mutations in skin, head, and neck cancers. Also, our results show significant differences in nt2298 allele frequencies between normal individuals and skin malignant tumors (P < 0.05). The results suggest that this polymorphism affects TP21 transactivator binding and may be important during the pathogenesis of skin cancer.     

Molecular and Microdomain Orientation in Semicrystalline Block Copolymer Thin Films by Directional Crystallization of the Solvent and Epitaxy

The directional crystallization of crystallizable organic solvents and the subsequent epitaxial crystallization of crystalline blocks onto the surface of crystalline substrates in semicrystalline block copolymers, control both molecular chain orientation of the crystalline block and the microdomain structure of the block copolymer. Thin film of semicrystalline polystyrene‐block‐poly(ethylene‐alt‐propylene)‐block‐polyethylene (PS/PEP/PE) terpolymer and polystyrene‐block‐polyethylene (PS/PE) diblock copolymer, which both contain crystallizable polyethylene (PE) blocks, have been patterned using benzoic acid (BA) and anthracene (AN) as crystallizable solvents. The directional crystallization induces orientation of the microdomains and epitaxy, due to the crystallographic matching of unit cells between the crystalline PE blocks and the crystalline organic substrates, resulting in the development of highly aligned crystalline PE blocks. The orientation of the PE crystals onto the substrate is evidenced by selected area electron diffraction and bright field transmission electron microscope images. In the case of the PS/PEP/PE terpolymer, the process induces the PS cylinders to align parallel to the b axis of the BA crystals. Long crystalline PE lamellae are oriented edge‐on on the BA surface, with the b axis of PE parallel to the b axis of BA, and parallel to the PS cylinders. In the case of the PS/PE diblock copolymer, the PE cylinders are oriented perpendicular to substrate, packed on a hexagonal lattice. Each cylinder contains precisely one crystalline PE lamella oriented edge‐on on the substrate. When BA is used, the PE lamellae inside cylinders are oriented with the b axis parallel to the b axis of BA crystals. When AN is used, due to the different epitaxial relationship between PE block and AN crystals, the PE lamellae are oriented along two equivalent directions, with the c axis parallel to the [110] and direction of AN crystals.

Schematic model of the final microstructure generated by combination of the directional crystallization and epitaxy.     

Erratum: Neurofibromatosis type 1 (NF1): Identification of eight unreported mutations in NF1 gene in Italian patients

In the original version of this article, the title was incorrect. Please find the correct title given here. The publisher deeply regrets this error. The original article to which this Erratum refers was published in Human Mutation 22:179–180 Human Mutation(2003) 22(2) 179–180     

Impaired macrophage responses may contribute to exacerbation of blood-stage Plasmodium chabaudi chabaudi malaria in interleukin-12-deficient mice.

Aiming to clarify the role of endogenous interleukin-12 (IL-12) in protective immunity against blood stages of Plasmodium chabaudi chabaudi (AS), we evaluated the course of infection in IL-12p40 gene knockout (IL-12p40KO) and wild-type (WT) C57BL/6 mice, focusing (1) on the ability of T cells to develop adequate type 1 responses and (2) on the potentiality of macrophages to respond to parasites, interferon-gamma (IFN-gamma), or both. We observed that IL-12p40KO mice develop significantly higher parasitemias during the acute infection, although mice from both groups clear the parasites within a month and similarly eliminate a secondary challenge. Thus, fully protective immunity to P. c. chabaudi can be generated in the absence of IL-12. However, this cytokine may promote parasite control during the early phase of infection. The increased acute parasitemia of IL-12p40KO mice was associated with both impaired IFN-gamma and nitric oxide (NO) response by spleen cells. Because stimulation with recombinant IFN-gamma (rIFN-gamma) failed to improve the NO response in IL-12p40KO macrophages, we investigated whether these cells have an intrinsic defect. Analysis of peritoneal macrophages revealed that IL-12p40KO cells produce higher levels of transforming growth factor-beta1 (TGF-beta1) compared with WT cells and respond to infected erythrocytes or rIFN-gamma by releasing little NO. Moreover, IL-12p40KO macrophages had a severely impaired ability to internalize opsonized infected erythrocytes, suggesting that the low effector profile assumed by these cells may compromise antibody-mediated immunity. Taken together, our results support the idea that the absence of IL-12p40 not only affects IFN-gamma production but also has deep consequences in macrophage effector functions that may contribute to exacerbation of the early phase of P. c. chabaudi malaria.     

Solitary fibrous tumour of the thyroid: Clinicopathological,immunohistochemical and ultrastructural study of three cases

We describe three cases of solitary fibrous tumour (SFT) arising from thyroid stroma. Grossly, the tumours were clearly delimited but only partly encapsulated. The following histomorphological growth patterns were observed: bundles of cells in storiform configuration; non-structured bundles; prevalence of fibrous matrix; highly cellular, non-structured; prevalence of loose, non-structured extracellular substance; cellular proliferation and vascular spaces in a haemangiopericytic configuration and a lipomatous component. Immunohistochemical investigation demonstrated intense, diffuse vimentin positivity and focal, less intense actin positivity in all three cases. At electron microscopy we observed a primitive cell of mesenchymal type, with cytoplasm poor in organelles and rich in filaments; this cell sometimes presented differentiation characteristics. SFT is at present the most correct term for the lesions presented here despite some morphological characteristics which differ from cases reported in the literature.     

Sensitive and viable identification of antigen-specific CD8+ T cells by a flow cytometric assay for degranulation

Flow cytometric detection of antigen-specific CD8+ T cells has previously been limited to MHC-class I tetramer staining or intracellular cytokine production, neither of which measure the cytolytic potential of these cells. Here we present a novel technique to enumerate antigen-specific CD8+ T cells using a marker expressed on the cell surface following activation induced degranulation, a necessary precursor of cytolysis. This assay measures the exposure of CD107a and b, present in the membrane of cytotoxic granules, onto the cell surface as a result of degranulation. Acquisition of cell surface CD107a and b is associated with loss of intracellular perforin and is inhibited by colchicine, indicating that exposure of CD107a and b to the cell surface is dependent on degranulation. CD107a and b are expressed on the cell surface of CD8+ T cells following activation with cognate peptide, concordant with production of intracellular IFNgamma. Finally, CD107-expressing CD8+ T cells are shown to mediate cytolytic activity in an antigen-specific manner. Measurement of CD107a and b expression can also be combined with MHC-class I tetramer labeling and intracellular cytokine staining to provide a more complete assessment of the functionality of CD8+T cells expressing cognate T cell receptors (TCR).     

Behavioral control of abnormal breathing in sleep

Behavioral control of abnormal breathing in sleep was studied to determine if an intervention procedure could reduce apnea duration and also SaO ₂ (blood oxygen) desaturation levels. Sleep apnea patients (n=11) were instructed while awake that tones would be presented in sleep whenever an apnea event occurred. They were told to breathe deeply to the tones and were given practice in doing so. Intervention and nonintervention hours alternated across 2 nights following 2 baseline nights. As expected, during the intervention hours, the duration but not the frequency of apneic events was reduced. The procedure also resulted in higher SaO ₂ levels during the intervention hours. Daytime sleepiness was not greater following intervention but sleep staging effects were observed. The results are sufficiently promising to warrant additional research.This research was supported by NIH Grants 2 HL 27149-84 and HL 34125 entitled Behavioral Control of Respiration in Sleep.     

Immunohistochemical localization of laminin, collagen IV and fibronectin in dysplasias and neoplasms of the cervix uteri

The distribution of intrinsic components (Laminin and Type IV Collagen) and extrinsic component (Fibronectin) of the Basement Membrane (BM) has been studied in normal uterine cervix (16 cases), in cervical dysplasia (14 cases) and in invasive carcinoma (45 cases). We found that BM staining for Laminin and Type IV collagen is linear and continuous underlying normal and dysplastic epithelium (CIN 1-CIN 2), it shows minor breaks in continuity and alterations of linearity in situ carcinomas (CIN 3), and it disappears in microinvasive areas. In well differentiated invasive carcinomas only focal disruptions of BM around neoplastic nests is noted; in contrast, in moderately and poorly differentiated neoplasias, is found a progressive reduction and loss of staining for Laminin and Type IV Collagen. The results of this study suggest that the distribution patterns of BM intrinsic components are in relation to the histological grade of cervical neoplasias and their invasion ability. On the contrary Fibronectin doesn't show any distribution pattern related to the grade of cervical neoplasias, its immunostaining increased with the rise of both connective tissue stroma production and of vascularity.     

Inflammatory myofibroblastic tumor (plasma cell granuloma). Clinicopathologic study of 20 cases with immunohistochemical and ultrastructural observations

Twenty cases of inflammatory myofibroblastic tumor (IMT) were studied; 19 involved the lung and 1 the esophagus only. The patients' ages ranged from 3 to 72 years. There were 9 males and 11 females. Involvement of a bronchus was seen in one case and of mediastinal structures in four. Chest pain and dyspnea were common symptoms; eight patients were asymptomatic. Seven patients underwent lobectomy, 12 local excision, and 1 biopsy alone. The lesions were nonencapsulated and ranged from 1.2 to 15 cm. Various proportions of plasma cells, histiocytes, and spindle cells were observed; the latter corresponded ultrastructurally to fibroblasts and myofibroblasts, were immunoreactive for vimentin and actin and focally for desmin, and were negative for epithelial markers. Plasma cells were polyclonal for light chains. One patient had two recurrences, and in one case a large pleural IMT was found eight years after the excision of a similar lesion in the lung. All patients with follow-up (ten) were well as long as ten years after the diagnosis (average, 3.7 years).