Origin of malignant centrofacial granulomas: surface markers and gene rearrangement of malignant cells

Malignant centrofacial granuloma (MCFG) is a clinical entity characterized by a relentless ulceration of the upper airway involving the nose, palate, and face, without any demonstrable etiology. The origin of 11 cases were analyzed with the help of cell-surface immunostaining in all and with T-cell receptor gene (TCR) rearrangement in 3. The results show that most of the cases of MCFG are in fact T-cell lymphomas with cell-surface antigens (CD2, CD7, CD3) consistent with either early or mature T lymphocytes. However, some cases exhibit B-lymphoid (CD19, CD20) or histiomonocytic (CD13, CD14) lineage-specific markers. In conclusion, despite its remarkable clinical unity, MCFG is a heterogeneous group of neoplastic diseases, most but not all of which may be classified as T-cell lymphoma.     

PCR can help early diagnosis of pulmonary tuberculosis

One hundred and fifty-one patients, clinically suspected for pulmonary tuberculosis (age: 31 +/- 13 years, male/female: 112/39), were investigated to evaluate the diagnostic potential of polymerase chain reaction (PCR) based detection of the Mycobacterium tuberculosis complex in sputum. The diagnostic efficacy of PCR was compared with culture of Mycobacterium tuberculosis on egg-based Lowenstein-Jensen modified medium. PCR detected 71.5% (108/151), whereas culture detected 66.2% (100/151) of the clinically suspected patients. There was a significant association between the results of PCR and culture (chi2 = 59.524, p < 0.001). However, 23.2% (35/151) samples were found negative in both culture and PCR. Considering culture as the gold standard, the sensitivity of the PCR was 92%. and its specificity 70%. This lower apparent specificity may be due to the higher sensitivity of PCR.     

Validation of a morphometric method for evaluating fibroblast numbers in normal and pathologic tissues

The aim of this work was to validate an image analysis method, based on cell nuclei form factor determination, for counting fibroblasts within human dermis. We first used reconstructed dermal equivalents in which fibroblasts can also be counted directly after lysis of the collagen matrix. We found a good correlation between the results of direct counting and those of image analysis from day 10 to day 28 of culture. When applied to young normal donors' skin biopsies fixed in Bouin's solution and embedded in paraffin, the image analysis method yielded mid-dermis fibroblast counts of between 2100 and 4100 per mm3 of fresh tissue. A nuclear form factor (FF) comprised between 0.35 and 0.84 was found to be a biologic marker of fibroblasts. This was confirmed after fibroblast discrimination from other cell types, which had rounder nuclei (FF >/= 0.85) and were identified either by their location (e.g. endothelial cells) or by labeling with specific antibodies (e.g. lymphocytes and monocytes/macrophages). Similar results were obtained with seven healthy donors' skin biopsies that had been frozen in nitrogen liquid and cryostat-sectioned, showing that this counting method is independent of the histologic procedure. Finally, analysis of samples of hypertrophic scars from two patients revealed that fibroblast density in some parts of the dermis was more than twice the value found in other parts presenting a fibroblast density almost normal, showing that this cell counting method can also be used to assess fibroblast heterogeneity within a given tissue.     

Tumour specific promoter region methylation of the human homologue of the Drosophila Roundabout gene DUTT1 (ROBO1) in human cancers

The human homologue of the Drosophila Roundabout gene DUTT1 (Deleted in U Twenty Twenty) or ROBO1 (Locus Link ID 6091), a member of the NCAM family of receptors, was recently cloned from the lung cancer tumour suppressor gene region 2 (LCTSGR2 or U2020 region) at 3p12. DUTT1 maps within a region of overlapping homozygous deletions characterized in both small cell lung cancer lines (SCLC) and in a breast cancer line. In this report we (a) defined the genomic organization of the DUTT1 gene, (b) performed mutation and expression analysis of DUTT1 in lung, breast and kidney cancers, (c) identified tumour specific promoter region methylation of DUTT1 in human cancers. The gene was found to contain 29 exons and spans at least 240 kb of genomic sequence. The 5' region contains a CpG island, and the poly(A)(+) tail has an atypical 5'-GATAAA-3' signal. We analysed DUTT1 for mutations in lung, breast and kidney cancers, no inactivating mutations were detected by PCR-SSCP. However, seven germline missense changes were found and characterized. DUTT1 expression was not detectable in one out of 18 breast tumour lines analysed by RT-PCR. Bisulfite sequencing of the promoter region of DUTT1 gene in the HTB-19 breast tumour cell line (not expressing DUTT1) showed complete hypermethylation of CpG sites within the promoter region of the DUTT1 gene (-244 to +27 relative to the translation start site). The expression of DUTT1 gene was reactivated in HTB-19 after treatment with the demethylating agent 5-aza-2'-deoxycytidine. The same region was also found to be hypermethylated in six out of 32 (19%) primary invasive breast carcinomas and eight out of 44 (18%) primary clear cell renal cell carcinomas (CC-RCC) and in one out of 26 (4%) primary NSCLC tumours. Furthermore 80% of breast and 75% of CC-RCC tumours showing DUTT1 methylation had allelic losses for 3p12 markers hence obeying Knudson's two hit hypothesis. Our findings suggest that DUTT1 warrants further analysis as a candidate for the tumour suppressor gene (TSG) at 3p12, a region defined by hemi and homozygous deletions and functional analysis.     

Dapsone for autoimmune thrombocytopenic purpura

Twenty-one human immunodeficiency virus (HIV)-free and six HIV-infected adults with autoimmune thrombocytopenic purpura (AITP) were treated with dapsone (100 mg/day). A response was observed in 13 patients (median platelet count before 25 × 10⁹/L, range 3–49; after 109 × 10⁹/L, range 69–241). Thrombocytopenia recurred in four of the responders in whom dapsone was discontinued. No response was observed in 12 patients. Dapsone had to be withdrawn after two weeks of treatment in the remaining two patients and after six to eight weeks in three other patients due to intolerance. No serious hematological complications were observed. These results confirm that dapsone is a safe, inexpensive, and effective treatment of AITP. © 1993 Wiley-Liss, Inc.     

Characterization of neurons born and incorporated into a vocal control nucleus during avian song learning

In male zebra finches, song learning is accompanied by the addition of new neurons to Area X, a nucleus necessary for normal song development. We examined whether Area X neurons born after 15 days post-hatch are recruited into the efferent pathway from Area X to the dorsolateral nucleus of the medial anterior thalamus (DLM). Our data suggest that the majority of these new Area X neurons are interneurons and that DLM-projecting neurons are incorporated into Area X prior to song learning.     

CpG island promoter hypermethylation of a novel Ras-effector gene RASSF2A is an early event in colon carcinogenesis and correlates inversely with K-ras mutations

We report in silico identification and characterisation of a novel member of the ras association domain family 1 (RASSF1)/NORE1 family, namely, RASSF2, located at chromosomal region 20p13. It has three isoforms, all contain a ras association domain in the C-terminus. The longest isoform RASSF2A contains a 5' CpG island. RASSF2A was cloned from a brain cDNA library and directly sequenced, confirming the genomic gene structure. In previous reports, we and others have demonstrated that RASSF1A is epigenetically inactivated in a variety of cancers, including sporadic colorectal cancer (CRC). In the present report, we analysed the methylation status of RASSF2A promoter region CpG island in sporadic CRC and compared it to K-ras mutation status. RASSF2A promoter region CpG island was hypermethylated in a majority of colorectal tumour cell lines (89%) and in primary colorectal tumours (70%), while DNA from matched normal mucosa was found to be unmethylated (tumour-specific methylation). RASSF2A expression was reactivated in methylated tumour cell lines after treatment with 5-aza 2-deoxycytidine. RASSF2A methylation is an early event, detectable in 7/8 colon adenomas. Furthermore, 75% of colorectal tumours with RASSF2A methylation had no K-ras mutations (codons, 12 and 13) (P=0.048), Fisher's exact test). Our data demonstrate that RASSF2A is frequently inactivated in CRCs by CpG island promoter hypermethylation, and that epigenetic (RASSF2A) and genetic (K-ras) changes are mutually exclusive and provide alternative pathways for affecting Ras signalling.