Muscle apoptosis in humans occurs in normal and denervated muscle, but not in myotonic dystrophy, dystrophinopathies or inflammatory disease

Recent data suggest that death of muscle cells during development and in selected pathological conditions occurs via apoptosis. We investigated the occurrence of apoptosis in normal and pathological human skeletal muscle, using in situ end-labeling (ISEL) to detect DNA fragmentation, and immunohistochemistry for the expression of tissue transglutaminase and interleukin-1beta-converting enzyme (ICE)-like proteases. In normal subjects, apoptotic myonuclei were occasionally observed as evidence of normal tissue turnover. Myonuclear apoptosis due to a deficit of trophic support from nerve cells also occurred in spinal muscular atrophies. No apoptosis of muscle cells was found in dystrophinopathies, myotonic dystrophy and inflammatory myopathies, suggesting that death of myofibers in those conditions is not due to activation of a gene-directed program of death. In dystrophinopathies and inflammatory myopathies, apoptosis was found in interstitial mononuclear cells, as a likely mechanism of clearance of the inflammatory infiltrates.

Role of apoptosis in the prognosis of oligodendrogliomas

Prognostic factors in oligodendrogliomas are not well defined, even considering the labeling index of proliferation markers. As in other neuroepithelial tumors, the difficulty in calculating cell loss may contribute to this uncertainty. Proliferation markers Ki-67/MIB.1 and PCNA, mitoses, apoptotic nuclei, p53 and bcl-2 expression were investigated in 98 oligodendrogliomas. Apoptosis was assessed by the aspect of nuclei, by in situ end-labeling (ISEL) technique and by c-Jun immunohistochemical demonstration. The Bcl-2 also was immunohistochemically studied for its anti-apoptotic role. Mitotic index (MI), labeling index (LI) for MIB.1 and PCNA and apoptotic index (AI) were calculated and compared among themselves and with histology and survival. It was found that AI correlated with MI (p = 0.001) and was significantly higher in anaplastic than in classic oligodendrogliomas (p = 0.001). Apoptosis occurred only slightly more frequently in cases with high LIs for proliferation markers (MIB.1 and PCNA) (p = non-significant) and it was definitely higher in p53-positive cases (p = 0.008). It did not correlate with bcl-2 which was poorly expressed in oligodendrogliomas, with the exception of cells with astrocytic features. Apoptotic index correlated very weakly with survival (p = 0.05); therefore, it cannot be considered a highly reliable prognostic factor in oligodendrogliomas.

In situ hybridization analysis of Girk2 expression in the developing central nervous system in normal and weaver mice

A mutation in the gene Girk2 that encodes an inwardly rectifying potassium channel is the genetic defect causing the behavioral and pathologic abnormalities of the weaver mutant mouse. Of the pathologic abnormalities, the best studied is the neuronal degeneration that occurs in the cerebellar cortex and in the midbrain dopaminergic neurons. A detailed characterization of the topographic and temporal expression of Girk2 is fundamental to elucidate the mechanisms underlying neurodegeneration in these mutant mice. In this study we utilized in situ hybridization to determine the expression of Girk2 mRNA during prenatal and postnatal development in the murine central nervous system (CNS). Girk2 expression was seen in multiple regions of embryonic CNS including the cerebellum and midbrain. During postnatal development, the highest expression was seen in the cerebellum, midbrain and hippocampus. However, since the developing cerebellum undergoes significant neuronal loss due to the degeneration of granule cell precursors, Girk2 mRNA expression in this area decreases progressively.

Alteration of the expression of human estrogen receptor gene by distamycin

The effects of distamycin on the expression of the estrogen receptor gene were determined in the MCF7 human breast cancer cell line. Estrogen receptor (ER) RNA transcripts were analyzed by Northern blotting and RT-PCR using specific oligonucleotides for the 5' upstream region and for ER cDNA. After ex vivo distamycin treatment of the cells the expression of the canonical ER mRNA isoform of 6.3 kb is strongly inhibited, without appreciable alteration of the accumulation of 5' upstream ER mRNA isoforms. These results suggest that distamycin alters the transcriptional activity of the ER gene causing a change in the ratio between the canonical transcript and other isoforms containing 5' upstream regions.

Differential effects of distamycin analogues on amplification of human gene sequences by polymerase-chain reaction

In this report we analyse the effects of distamycin and five distamycin analogues on amplification by polymerase-chain reaction (PCR) of two gene sequences displaying a different A+T/G+C content. The first was a 5' region of the human oestrogen receptor (ER) gene, containing a (TA)26 stretch; the second was a CG-rich sequence of the human Ha-ras oncogene. The results obtained unequivocally demonstrate that the addition of one pyrrole ring significantly improves the ability of distamycin derivatives to interfere with PCR-mediated amplification of the human ER genomic region carrying a (TA)26 stretch. The distamycin analogues analysed differ in the number of pyrrole rings and in the presence of an N-formyl, an N-formimidoyl or a retroamide group at position X1. Among compounds carrying the same number of pyrrole rings, those carrying an N-formyl or an N-formimidoyl group retain a similar inhibitory activity. The retroamide analogues, on the contrary, are much less efficient in inhibiting PCR-mediated amplification of the 5'ER region. With respect to sequence selectivity both distamycin and distamycin analogues exhibit a sequence preference, since they do not inhibit PCR amplification of Ha-ras CG-rich gene regions, with the exception of a distamycin analogue carrying four pyrrole rings.

Polymerase-chain reaction as a tool for investigations on sequence-selectivity of DNA-drugs interactions

Sequence-selectivity of DNA-binding drugs was recently reported in a number of studies employing footprinting and gel retardation approaches. In this paper we performed polymerase-chain reaction (PCR) experiments to study the in vitro effects of distamycin, daunomycin, chromomycin and mithramycin. As model systems we employed the human estrogen receptor (ER) gene and the Harvey-ras (Ha-ras) oncogene, in order to obtain PCR products significantly differing for the A + T/G + C frequency ratio. Distamycin, daunomycin, chromomycin and mithramycin are indeed known to differentially bind to different DNA regions depending upon the DNA sequences recognized. The main conclusion of our experiments is that distamycin, daunomycin, chromomycin and mithramycin inhibit polymerase-chain reaction in a sequence-dependent manner. Distamycin inhibits indeed PCR mediated amplification of AT-rich regions of the human estrogen receptor gene, displaying no inhibitory effects on PCR-mediated amplification of GC-rich sequences of Ha-ras oncogene. By contrast daunomycin, chromomycin and mithramycin were found to inhibit PCR-mediated amplification of the Ha-ras GC-rich oncogene sequences. We propose that polymerase-chain reaction technique could be applied to study the in vivo interactions of DNA-binding drugs to specific genes in intact cells.

Novel small deletions of the p53 gene in late-stage B-cell chronic lymphocytic leukaemia

A group of 20 CLL patients selected for advanced clinical stage p53 mutations were analysed by single-strand conformational polymorphism (SSCP) following PCR amplification of exons 5-9. In two patients abnormal SSCP of either exon 5 or exon 8 was found and PCR products were analysed by direct sequencing. A hemizygous or homozygous 12bp deletion at codon 135 and 3bp heterozygous deletion at codon 264 were detected; also, in the latter sample a heterozygous mutation at codon 282 (Arg to Gln) was found. To our knowledge, this is the first report of p53 deletions in B-CLL. The two patients were elderly, and both had a rapidly progressive disease in the absence of unfavourable cytogenic abnormalities. These findings support a role for p53 alterations in the clinical course of some B-CLL patients.

bcl-2 protein expression in aged brain and neurodegenerative diseases

The proto-oncogene bcl-2 is involved in the regulation of cell death and is able to block apoptosis in neurones through reduced generation of reactive oxygen species (ROS). We have studied the immunohistochemical expression of bcl-2 protein in the aged brain and in various human neurodegenerative diseases. In all cases, bcl-2 was strongly enriched within lipofuscin and autophagic vacuoles of neurones, glial and vascular cells. Our data show that accumulation of bcl-2 is not disease-specific and represents a general cellular response which accompanies the increased formation of lipofuscin. Since oxidative stress is directly involved in lipofuscinogenesis, accumulation of bcl-2 may reflect a mechanism for counterbalancing ROS-mediated damage, or it might represent the impairment of bcl-2-dependent protection from ROS.

Iomeprol and iopamidol in cardiac angiography: a randomised, double-blind, parallel-group comparison

During cardiac angiography, hemodynamic alterations and surface electrocardiographic changes are common, predictable and dose-related adverse reactions to radiocontrast media. High osmolality, inadequate sodium content and local transient hypocalcemia are thought to be the main mechanisms responsible for these untoward cardiovascular effects. The purpose of this double-blind, parallel-group trial was to compare the hemodynamic and electrocardiographic responses to cardiac and selective coronary artery injection of iomeprol 400 (400 mgI/ml) and iopamidol 370 (370 mgI/ml). One-hundred consenting adult inpatients were randomised to receive iomeprol 400 (41 males, nine females; mean age, 56.6 years) or iopamidol 370 (46 males, four females; mean age, 57.6 years). Both agents produced minor and transient hemodynamic and electrophysiological effects. Following left ventriculography, iopamidol 370 produced a significantly greater increase in LVEDP than iomeprol 400 (mean increases after first and second left ventriculogram: 2.5 and 4.6 mmHg with iomeprol 400, 3.3 and 9.9 mmHg with iopamidol 370, P = 0.027). The QT-interval was more affected by iopamidol 370 than by iomeprol 400. However, post-contrast prolongation of the QT-interval was not significant with either agent, nor were there any significant T-wave, ST-segment or RR-interval changes associated with the injection of the test compounds. No serious adverse events occurred throughout the study. Mild pain was complained by only one patient, while most patients reported mild to moderate sensation of heat. Image quality of the vast majority of the procedures was rated as good or excellent in both patient groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Loss of heterozygosity in ovarian cancer: detection by PCR and microsatellite polymorphism

Loss of chromosome 6q was investigated in endometrial and ovarian carcinomas by a PCR based-microsatellite polymorphism analysis. Results obtained show that this technique is able to detect frequent loss of heterozygosity in the ovarian cancers (10/27) and only in the serous type (8/17). Then, this kind of analysis can contribute to the understanding of tumor development and progression of ovarian cancers with different histopathological features.

Androgen responsiveness and androgen receptor gene expression in human kidney cells in continuous culture

The effects of androgen and estrogen on cell growth and gene expression were investigated in KJ29 kidney epithelial cells. Incorporation of 3H leucine and 3H thymidine was increased by androgen at 10nM, but not by estrogen. Estrogen however, inhibited the effects induced by androgen. In addition, cell number and the proliferation marker Ki67 were increased by androgen, but not by estrogen. Levels of androgen receptor RNA, as detected by RT-PCR and Northern blot analysis, were not affected by either androgen or estrogen. Levels of estrogen receptor RNA could be detected only by RT-PCR, and disappeared after estrogen treatment. These studies show that sex steroid receptors are differently expressed in KJ29 cells, and suggest that androgen, via its canonic receptor, acts as a mitogenic factor in human kidney cells, whereas estrogen has an antiandrogenic action.

Sequencing of an RNA transcript of the human estrogen receptor gene: evidence for a new transcriptional event

Two transcripts of the human estrogen receptor (ER) gene have been described, ER mRNA 1 and mRNA 2, different in their 5' untranslated region. By performing reverse transcriptase-polymerase chain reaction with oligonucleotides specific for the 5' genomic region of the human ER gene we have identified a new ER RNA transcript. The sequence analysis of cDNA from MCF7 breast cancer cells and endometrial human tissues demonstrates that this transcript originates further upstream of the initiation transcription sites so far proposed. Primer extension analysis on RNA from MCF7 cells reveals in the upstream region a possible transcription start site at -3090. In agreement with this result, Northern blot analysis shows, in addition to the canonical 6.3 kb ER mRNA, an ER RNA transcript of approx. 7.4 kb in size. The presence of the additional ER mRNA suggests the existence of a new upstream 5' promoter directing transcription of the human ER gene.

Retinoic acid-induced decrease of DNA synthesis and peroxidase mRNA levels in human thyroid cells expressing retinoic acid receptor alpha mRNA

In order to clarify the effect of retinoids on thyroid cell growth and function, the presence of retinoic acid receptors (RARs) and the action of retinoic acid (RA) on DNA synthesis and on thyroid peroxidase (TPO) and thyroglobulin (TGB) mRNA expression were investigated in primary cultures of human thyroid follicular cells. A time and dose-dependent reduction in 3H-thymidine (3H-thy) incorporation was found in cells exposed for 48 h to all-trans-RA up to 1 microM. A cytotoxic effect was found only with the higher dose of 50 microM. The RA-induced decrease of 3H-thy incorporation was reflected by parallel change in DNA content of cell monolayers. The inhibitory effect of 1 microM RA on 3H-thy incorporation ranged from 28.5 +/- 4.6% in normal cells to 42 +/- 3.2% in adenomatous cells. In addition, 1 microM RA significantly reduced basal and TSH-induced TPO mRNA levels in normal, goitrous and adenomatous cells, but did not alter TGB mRNA levels. Furthermore, in these cells the study of RAR alpha and beta mRNA showed the presence of two major RAR alpha mRNA transcripts of approximately 3.5 and 2.8 Kb in size, whereas RAR beta mRNA was undetectable. Overall, our data indicate that RAR alpha gene is expressed in human thyrocytes and that RA may be involved in the regulation of the human thyroid by reducing proliferation and function of follicular cells.

Simplified construction and characterization of yeast artificial chromosome libraries

Three yeast artificial chromosome (YAC) libraries were constructed using two human cell lines and the pYAC-RC vector. The main differences from the previously described methods were: i) genomic DNA was digested in low melting point (LMP) agarose blocks with the rare cutting enzyme ClaI; ii) DNA was ligated in melted LMP agarose after agarase treatment; iii) spheroplast regeneration plating was done in calcium alginate thin layer. In addition, a panel of PCR primers was used to identify quickly the presence in the libraries of repetitive and single copy human DNA sequences.

Cyclosporin-A increases type I procollagen production and mRNA level in human gingival fibroblasts in vitro

In order to study the pathogenesis of gingival overgrowth induced by the immunosuppressive drug cyclosporine-A (CyA), we investigated its effect on 3H thymidine incorporation and on collagen production and mRNA levels in fibroblast cultures obtained from normal human gingiva. At concentrations of 100, 500 and 1000 ng/ml, CyA did not modify thymidine incorporation after 24 and 72 h of incubation. However, after 24 h it significantly increased the level of 3H proline-containing proteins in the medium. In addition, CyA increased alpha-procollagen chains by up to three times. This CyA-induced change was related to a rise in the level of type I procollagen. The CyA effect on fibroblasts was markedly reduced by cycloheximide, an inhibitor of protein synthesis, and it correlated well with an increase of type I procollagen mRNA. Overall, our data indicate a direct stimulatory action of CyA on collagen synthesis, but not on DNA synthesis, in human gingival fibroblasts.

Analysis of upstream sequences of the human estrogen receptor gene

An upstream region of the human estrogen receptor gene (ER) spanning from -2776 to -38 in relation to a previously described exon 1 was sequenced and analyzed for the possible presence of open reading frames (ORF) and regulatory motifs. We identified a long 459 bp ORF beginning at -2301. Most of the transcriptional regulatory motifs present within the ER upstream sequence are distributed either upstream or downstream of this long ORF which displays a TATA box, a CACC motif and a canonical cap site in the 5' flanking region.

A c-myc gene variant without exon 1 and with an abnormal methylation pattern inherited in a woman with no evidence of malignancy

A c-myc DNA with a deletion which includes 5' flanking, exon 1 and intron I sequences has been found in normal white blood cells of a mother and one daughter in a Northern Italian family. In addition, the degree of methylation of specific CCGG sites in the truncated DNA is lower in both mother and daughter than that found in normal DNA. It is of interest that deletions of the first exon and hypomethylation of the c-myc gene have usually been observed only in some neoplasias. However, our results demonstrate that the c-myc truncated DNA with the abnormal methylation pattern here reported is a genomic variant which by itself is not related to neoplastic transformation.

Somatostatin reduces 3H-thymidine incorporation and c-myc, but not thyroglobulin ribonucleic acid levels in human thyroid follicular cells in vitro

The action of somatostatin (SRIH) on 3H-thymidine (thy) incorporation and on c-myc and thyroglobulin RNA levels in a suspension of follicles from normal and goitrous human thyroid was examined. SRIH, at 10(-7) M concentration, inhibited basal thy incorporation (maximally by 4 h lasting for up 24 h), which effect was greater in goiter than in normal thyroid and was also detected in growing adherent epithelial cells. Moreover, in a follicle suspension SRIH prevented TSH-stimulated thy incorporation, both in normal and in goitrous thyroid. Basal expression of c-myc RNA was not affected by SRIH in either tissue, whereas the TSH-stimulated c-myc RNA level was significantly reduced in goiter. No effect of SRIH was observed on basal or TSH-stimulated thyroglobulin RNA levels. SRIH did not alter basal cAMP concentrations in normal or goitrous follicles, but it significantly reduced TSH-stimulated cAMP accumulation both in normal thyroid and in goiter. Overall, our data indicate a direct inhibitory action of SRIH on growth, but not on differentiation, of human thyroid, probably by a mechanism not entirely cAMP dependent.

Transgenic mice mimic the methylation pattern of the human HLA-DR alpha gene

The methylation pattern of the human HLA-DR alpha gene has been studied in different tissues of transgenic mice. Offspring from two transgenic lines was selected for this analysis, carrying the integrated HLA-DR alpha gene in either single or multiple (8-10) copies per diploid genome. In transgenic animals two distinct methylation patterns of the HLA-DR alpha gene are generated, due to a complete methylation of all the GCGC and CCGG sites the former, and to unmethylation restricted to one or both the GCGC sites located in the 5' portion of the HLA-DR alpha gene, the latter. Unmethylation restricted to the 5' portion of the HLA-DR alpha gene is a highly conserved feature in human tissues and in vitro cultured cell lines; therefore, it is concluded that the methylation pattern of the human HLA-DR alpha transgene may be faithfully reconstituted in transgenic animals. Northern blotting analysis of the RNA isolated from tissues of the transgenic mouse carrying single-copy HLA-DR alpha transgene demonstrates its tissue specific expression, suggesting that transgenic mice may represent an "in vivo" experimental system to study the relationship between methylation state and transcriptional activation.