Expression of Met/hepatocyte growth factor receptor gene and malignant behavior of musculoskeletal tumors.

Overexpression of the hepatocyte growth factor receptor (Met/HGF receptor), a transmembrane tyrosine kinase encoded by the met proto-oncogene, has been associated with tumor progression in different human carcinomas. More recently, the Met/HGF receptor has also been described in tumor cell lines of mesenchymal origin, suggesting the existence of an autocrine loop that may contribute to the pathogenesis of sarcomas. In this study, we analyzed the expression of Met/HGF receptor by Western blotting and immunohistochemistry in frozen samples of 87 primary tumors of bone and soft tissues. Among benign tumors, overexpression was consistently found only in giant-cell tumor, a locally aggressive lesion that may also, although rarely, spread to the lung. Among malignant lesions, the presence of the Met/HGF receptor was detected in a relevant percentage of primaries and in almost all of the recurrences. The highest levels of Met/HGF receptor were found in osteosarcoma, a highly aggressive tumor that typically permeates the host bone and rapidly expands to the soft tissues. On the contrary, only low levels of Met/HGF receptor were found in chondrosarcoma, a slowly growing tumor that usually expands without massive destruction of the surrounding structures. These data indicate an association of Met/HGF expression with local aggressiveness in human mesenchymal tumors. The finding of Met/HGF receptor overexpression in all of the osteosarcomas suggests a role for the met proto-oncogene in the pathogenesis of this tumor.     

Cytogenetic and clinical studies in gonadal dysgenesis with 46,X,Xt(qter leads to p221::p223 leads to qter) karyotype: review and phenotype/karyotype correlations.

Chromosome analysis by Q, R, and C banding was performed in a case diagnosed clinically as gonadal dysgenesis and the karyotype was shown to be 46,X,Xt(qter leads to p221::p223 leads to qter). Localisation of the breakpoints in the fused X chromosomes and replication studies have led to a hypothesis on the origin of the translocation. A comparison of clinical and cytogenetical findings in this and other published cases has also been made in an attempt to detect some phenotype/karyotype correlations.     

Rapid molecular cytogenetic analysis of X-chromosomal microdeletions: Fluorescence in situ hybridization (FISH) for complex glycerol kinase deficiency

Diagnosis of X-chromosomal microdeletions has relied upon the traditional methods of Southern blotting and DNA amplification, with carrier identification requiring timeconsuming and unreliable dosage calculations. In this report, we describe rapid molecular cytogenetic identification of deleted DNA in affected males with the Xp21 contiguous gene syndrome (complex glycerol kinase deficiency, CGKD) and female carriers for this disorder. CGKD deletions involve the genes for glycerol kinase, Duchenne muscular dystrophy, and/or adrenal hypoplasia congenita. We report an improved method for diagnosis of deletions in individuals with CGKD and for identification of female carriers within their families, using fluorescence in situ hybridization (FISH) with a cosmid marker (cosmid 35) within the glycerol kinase gene. When used in combination with an Xq control probe, affected males demonstrate a single signal from the control probe, while female carriers demonstrate a normal chromosome with two signals, as well as a deleted chromosome with a single signal from the control probe. FISH analysis for CGKD provides the advantages of speed and accuracy for evaluation of submicroscopic X-chromosomal deletions, particularly in identification of female carriers. In addition to improving carrier evaluation, FISH will make prenatal diagnosis of CGKD more readily available. © 1995 Wiley-Liss, Inc.     

Interchromosomal duplications of the adrenoleukodystrophy locus: a phenomenon of pericentromeric plasticity

A 9.7 kb segment encompassing exons 7-10 of the adrenoleukodystrophy (ALD) locus of the X chromosome has duplicated to specific locations near the pericentromeric regions of human chromosomes 2p11,10p11, 16p11 and 22q11. Comparative sequence analysis reveals 92-96% nucleotide identity, indicating that the autosomal ALD paralogs arose relatively recently during the course of higher primate evolution (5-10 million years ago). Analysis of sequences flanking the duplication region identifies the presence of an unusual GCTTTTTGC repeat which may be a sequence-specific integration site for the process of pericentromeric- directed transposition. The breakpoint sequence and phylogenetic analysis predict a two-step transposition model, in which a duplication from Xq28 to pericentromeric 2p11 occurred once, followed by a rapid distribution of a larger duplicon cassette among the pericentromeric regions. In addition to facilitating more effective mutation detection among ALD patients, these findings provide further insight into the molecular basis underlying a pericentromeric-directed mechanism for non- homologous interchromosomal exchange.      

A one-year follow-up on the effects of raloxifene on thyroid function in postmenopausal women

OBJECTIVE: Estrogens increase serum thyroxine-binding globulin (TBG) and total thyroxine (TT4) concentrations. Serum free thyroxine (FT4) concentrations, however, remain normal. Raloxifene (RAL) is a selective estrogen receptor modulator used to treat postmenopausal osteoporosis. Data on the long-term effects of RAL on thyroid physiology are scanty. We evaluated the effects of RAL administration for 1 year on thyroid function in osteopenic, postmenopausal women. DESIGN: Fifty osteopenic, postmenopausal women were randomly assigned to receive either RAL (60 mg/day, n = 25) or placebo (PL, n = 25) for 1 year, in a double-blind study. Measurements of serum TBG, TT4, FT4, thyroid-stimulating hormone (TSH), thyroid hormone-binding ratio (THBR), FT4 index (FT4-I) and TT4/TBG ratio were carried out at baseline and after 4 and 12 months of therapy. RESULTS: Baseline values were similar in both treatment groups. Serum TBG concentrations were increased during RAL treatment from baseline values of 29.60 +/- 0.9 microg/mL to 31.45 +/- 1.33 and 32.34 +/- 1.37 microg/mL at 4 months and 1 year, respectively (P < 0.05, baseline v 1-year values) but were unchanged during PL treatment. A small, insignificant increase in TT4 and TSH concentrations occurred in the RAL group and no changes in the PL group. All other values were unchanged during either treatment. CONCLUSIONS: These results demonstrate that RAL significantly increased serum TBG levels, but the changes were small and not accompanied by changes in FT4-I, FT4, or TSH concentrations, suggesting that long-term RAL treatment is unlikely to clinically affect the thyroid status in euthyroid, postmenopausal women.     

Biologic effects of surface roughness and fluorhydroxyapatite coating on osteointegration in external fixation systems: an in vivo experimental study

The concomitant influence of surface roughness and fluorhydroxyapatite (FHA) coating of titanium (Ti) implants on bone response was investigated. For this purpose, titanium screw-shaped implants with a lower degree (Y371) and a higher degree (TiPore300) of surface roughness, coated with FHA and uncoated, were transversally inserted into the diaphyses of sheep tibiae for 12 weeks. Four sheep received Y371 (group A) and Y371 + FHA (group B) screws and four sheep received TiPore300 (group C) and TiPore300 + FHA (group D) screws. For each type of material, the morphology and microstructure of implant-facing bone were evaluated. The host bone of each tibia was used as a control. In all groups the bone tissue did not reach a complete maturation. The higher degree of roughness, perhaps due to an excessive irregularity of the surface, induced the worst osteointegration: a fibrous tissue layer between screw and new bone tissue was often present. Nevertheless, as viewed by XRD, no crystallographic change of the apatite lattice was observed in any of the implants. In contrast, the microhardness value, an index of bone mineralization, was higher in the uncoated screws and decreased progressively in the following order: group C > group A > group B > group D. The association of plasma spraying with roughness treatment constitutes a complex system that seems to interfere with bone mineralization. A chemical change of the surface, perhaps with more Ti release or more coating degradation, could be responsible for such impairment. The authors emphasize the necessity for simultaneous evaluation of surface topography and chemistry as well as an improvement in plasma-spraying and post-processing techniques and in standard procedures for materials characterization.     

Heterogeneous pattern of chromosomal breakpoints involving the MYC locus in multiple myeloma

Chromosomal rearrangements of the MYC locus, which often involve the IG loci, are recurrent events in multiple myeloma (MM) and plasma cell leukemia (PCL). We used dual-color fluorescence in situ hybridization (FISH) to characterize the breakpoint locations of chromosomal translocations/rearrangements involving the MYC locus at 8q24 found in a panel of 14 MM cell lines and 70 primary tumors (66 MM and 4 PCL). MYC locus alterations were observed in 21 cases: MYC/IG (mainly IGH@) fusions in 11 cell lines and three patients (2 MM and 1 PCL), and extra signals and/or abnormal MYC localizations in seven patients (5 MM and 2 PCL). Fourteen of these cases were investigated by FISH analyses by use of a panel of BAC clones covering about 6 Mb encompassing the MYC locus. The breakpoints were localized in a region 100-250 kb centromeric to MYC in four cases, a region 500-800 kb telomeric to the gene in four cases, and regions > or = 2 Mb centromeric or telomeric to MYC in five cases. Two different breakpoints were detected in the KMS-18 cell line, whereas the insertion of a MYC allele was found in a complex t(16;22) chromosomal translocation in the RPMI8226 cell line. Our data document a relatively high dispersion of 8q24 breakpoints in MM.     

Effect of Helicobacter pylori infection, age and epithelial cell turnover in a general population at high risk for gastric cancer

BACKGROUND: H. pylori and age are two known risk factors for atrophic gastritis and high epithelial cell turnover may be an indicator for preneoplastic changes in the stomach. We searched for an association between H. pylori, age and gastritis in the general population together with the proliferative state into the antral mucosa. METHODS: We examined gastric biopsies from antrum and corpus of 117 consecutive volunteers which were endoscoped during a population study in San Marino. H. pylori status was determined by serum IgG antibodies, rapid urease test on biopsies and histology. Presence of gastritis and grading of inflammation, activity, intestinal metaplasia and atrophy were ascertained using Sydney System. On a subsample of 36 subjects without endoscopic lesions we performed an immunohistochemical study on gastric cell proliferation using PCNA. A computer-aided count was made on stained epithelial cells to evaluate labeling index. Statistical analysis was performed using chi 2 test and linear regression. RESULTS: Inflammatory infiltrate (both activity and mononuclear cells), (p < 0.0001) and intestinal metaplasia (p < 0.004) were significantly higher in H. pylori positive subjects. Atrophic gastritis was present in 82% H. pylori positive subjects vs 17.6% (p < 0.0001). Labeling Index was significantly higher in H. pylori positive subjects (p < 0.005) and it was correlated with inflammation and atrophy (p = 0.001). Elderly H. pylori negative subjects have a lower cell turnover (p = 0.006) but H. pylori infected subjects do not show any decrease of Labeling Index with age. CONCLUSIONS: In the general population of an area with high gastric cancer rate, H. pylori infection is associated with atrophic gastritis and with hyperproliferative gastric cell state. These conditions are present either in young and old age and increase the neoplastic risk of gastric mucosa.