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M D'Erme

Publications and source records attributed to M D'Erme.

36 records · Page 2Linked to original sources
PubMed1991

Histones and DNA methylation in mammalian chromatin. Differential inhibition by histone H1.

Histones (from calf thymus or from human placenta), if renatured in the presence of EDTA, caused a severe inhibition of in vitro methylation of double-stranded DNA (from Micrococcus luteus) by human placenta DNA methyltransferase. The absence of EDTA during the histone renaturation procedure abolished--at least in the 'physiological' range of the histones/DNA ratio--the inhibition. The H1 component was responsible for this inhibition, no effect being exerted by the other histones. H1 preparations were more effective if renatured in the presence of EDTA--90% inhibition being reached at a 0.3:1 (w/w) H1/DNA ratio. It seems likely that the requirement for the presence of EDTA during the renaturation process is correlated to its ability to induce a fairly stable ordered conformation of the histones, although this effect could also be shown with the 'inactive' H2a, H2b and H3 components, and was instead less evident with histone H1. The restriction to histone H1 of the ability to inhibit enzymic DNA methylation may account for the lower methylation levels present in the internucleosomal DNA of mammalian chromatin.

Animals↗
PubMed1990

Persistence of azacytidine-induced SCEs and genomic methylation in CHO cells in vitro.

Many carcinogenic agents are able to affect the methylation level in mammalian cells cultivated in vitro. The capacity of azacytidine (AZA) to demethylate DNA can be used to examine the relationship between the genomic methylation level and cytogenetic end-points. Here we compared the sister-chromatid exchange (SCE) level with the genomic % methylcytosine in a Chinese hamster ovary cell line in vitro after giving a single 10-microM pulse of AZA. Both parameters were followed up to 16 cell cycles after the agent was removed. While the SCE level increased starting 2 cycles from the treatment and persisted for the entire 16 cycles, the methylcytosine level, after an initial 50% decrease, approached the control value, completely returning to it after 10 cell cycles. The possibility that the persistence in the SCE increase is an inherited phenomenon is discussed.

5-Methylcytosine↗
PubMed1990

Tightly-bound form of poly(ADP-ribose)polymerase in the higher order of chromatin organization.

A tightly-bound form of poly(ADP-ribose)polymerase is present, within the third level of rat testis chromatin structure, both in the loops and in chromatin matrix. When chromatin matrix was extensively digested with DNAaseI, only little residual enzymatic activity remained in the insoluble fraction, the extent of DNA hydrolysis being well correlated to the progressive loss of the poly(ADP-ribose)polymerase activity. These findings suggest that the tightly-bound form of the enzyme is not an intrinsic protein component of chromatin matrix but is only indirectly located in this structure, being rather associated to the attachment points of loop DNA on the matrix.

Animals↗
PubMed1982

Inhibitors binding to L-aromatic amino acid decarboxylase.

The effect of a number of inhibitors of L-aromatic amino acid decarboxylase activity on the absorption spectrum of the enzyme-bound coenzyme has been studied. It has been observed that the compounds tested, even if devoid of the amino function and therefore unable to form the Schiff base with the coenzyme, modify significantly the enzyme spectrum, indicating their binding to the coenzyme active site. Spectral modifications suggest that at least two kinds of binding of inhibitors to L-aromatic amino acid decarboxylase may occur, depending on their structural features. Moreover, from the spectra obtained at different concentrations of the inhibitors their affinity constants have been determined: data indicate that the cathecol ring gives the largest contribution to the binding, while the presence of the carboxyl group, the aminic group and the aliphatic chain are responsible for a decrease in the binding, which could be relevant for the efficiency of the catalysis.

Aromatic Amino Acid Decarboxylase Inhibitors↗
PubMedDate not supplied

High glucose modifies heparansulphate synthesis by mouse glomerular epithelial cells.

BACKGROUND: Alterations in proteoglycan metabolism are involved in the pathogenesis of diabetic nephropathy. The aim of this study is to evaluate the effects of high glucose on proteoglycan production and to find a reliable in vitro model for the study of diabetic nephropathy. METHODS: A clone of mouse glomerular epithelial cells was cultured in media containing elevated (30 mmol) and physiological (5 mmol) glucose, or iso-osmolar (30 mmol) mannitol concentrations. We evaluated the synthesis of 35SO4-labeled molecules and the amount of proteoglycans by Sepharose CL6B and DEAE-Sephacel chromatographies. RESULTS: A clear decrease (56%) in total cell-layer proteoglycan synthesis was induced by 30 mmol glucose, in comparison with normal glucose. A reduction of 25% in medium associated proteoglycan synthesis was observed in high glucose cultured cells. After Sepharose CL6B, in cells cultured in high glucose, cell layer heparansulphate proteoglycan-I (Kav 6B 0. 04) synthesis was reduced by about 81%, heparansulphate proteoglycan-II (Kav 6B 0.21) by about 87% and heparansulphate glycosaminoglycan (Kav 0.4-0.8) by about 91%, respectively. In mannitol-incubated cells the reductions observed were less evident and not significantly different from those in normal glucose. CONCLUSIONS: These results indicate that (1) glomerular epithelial cells play a central role in proteoglycan synthesis, (2) high glucose modifies the amount and influences the different species production of these macromolecules, while osmotic forces seem to be only partially involved in these effects, and (3) this cellular clone of glomerular epithelial cells can represent a reliable in vitro model for the study of the mechanisms involved in diabetic nephropathy.

Animals↗
PubMedDate not supplied

[Therapy of hepatic carcinoma by the intra-arterial injection of lipiodol, antineoplastic agents and gelfoam].

Chemoembolization by selective intra-arterial injection of lipiodol--chemotherapeutic agents (mitomycin and/or adriamycin)--followed by terminal embolization with gelfoam was performed on 20 inoperable patients with hepatic tumors: 13 hepatocellular carcinomas (HCC), 6 metastases from colorectal cancer, and one adenoma. A total of 29 embolizations were performed, 17 of them followed by gelfoam embolization. Significant decrease in tumor size or no tumor increase was shown in 8 patients--6 capsulated and well-limited HCC's, and 2 multinodular HCC's. Apart from occasional episodes of post-embolization syndrome (fever, vomit, abdominal pain), no significant complications were observed. Nine patients died at intervals ranging from 2 weeks to 37 months after the first embolization; in 6 patients the cause of death was not related to the advancing of the cancer, but to the complications of the underlying cirrhosis. In cirrhotic patients, damage to the rest of liver parenchyma can be limited by using superselective catheterization. Of the 6 patients with greater than 12 months follow-up, 4 are alive and 2 have died; 2 more patients are still alive 18 months after the first embolization. Finally, lipiodol was useful as radiopaque marker to detect lesion changes during the follow-up.

Adult↗
PubMedDate not supplied

Glycoprotein distribution in non-histone chromatin proteins from pig liver.

Carbohydrate content of non-histone proteins from pig liver chromatin has been measured in different groups of chromatin fractions and does not seem to be related to the affinity of the proteins for DNA. Glycoproteins are preferentially located in the nuclease-sensitive fractions of chromatin. A 59,000 dalton glycoprotein has been identified as a characteristic components of a chromatin fraction solubilized by DNAase II.

Animals↗
PubMedDate not supplied

[CT-guided percutaneous treatment of osteoid osteoma].

CT was used to localize and guide the percutaneous ablation of osteoid osteomas in 11 patients whose age ranged 5 to 63 years. The treatment was performed directly in the CT room ensuring maximum asepsis. General anesthesia was used in children and in vertebral and sacroiliac localizations, while the peripheral block was used in peripheral localizations. In the latter cases, an ischemic band was used to reduce bleeding. A dedicated drill resection system guided by a Kirschner guide wire was used for removal. The treatment was curative in the short period in all the patients, with complete symptom remission. Only one patient required retreatment after 6 months. In our series of patients no major complications, e.g., bleeding or infections, were observed. In 8 cases the resection yielded enough material for histology. To conclude, this technique can be considered a valuable alternative to surgery in the treatment of osteoid osteomas.

Adolescent↗
PubMedDate not supplied

[Ultra-low field magnetic resonance in the diagnosis of ovarian lesions].

To investigate the diagnostic capabilities of ultra low field MRI in the characterization of adnexal conditions, 46 women (aged 17 to 83 years) with US diagnosis of tubo-ovarian diseases were examined with MRI. An 0.064 T permanent magnet was used (toshiba Access), with T1- and T2-weighted spin-echo (SE) sequences, 3D T1-weighted gradient-echo (GE) sequences and, in 5 patients, a STIR sequence. Compared with surgical (37 patients), needle biopsy (3 patients) and clinical follow-up (6 patients) findings, MR diagnostic accuracy was 86.9%, which is comparable with literature data at higher field strength. The most common diagnostic error in our series was in the differential diagnosis between dermoid cyst and endometriosis which exhibited similar MR patterns. This limitation seems to be overcome by using STIR sequences with 60 ms T1 which, at this field strength, can suppress fat signal completely, whereas blood signal intensity remains high. The MR signal patterns of each group of conditions are also reported: in some cases, such patterns differ from those reported at higher field strength due to different T1 and T2 tissue relaxation times.

Abscess↗
PubMedDate not supplied

[Echography, magnetic resonance and double-contrast arthrography of the rotator cuff. A prospective study in 30 patients].

Shoulder pain is a common clinical problem with different etiologies. Without a specific diagnosis, treatment could be ineffective, causing functional limitation, chronic pain and atrophy. US and MRI allow in many cases to correctly define the different etiologies causing shoulder pain, often due to rotator cuff conditions. From June to September 1992, thirty patients with clinically suspected acute or chronic rotator cuff lesion were studied with US, MRI and double contrast arthrography. US and MRI findings were evaluated and compared using arthrography and surgery as the gold standard. The overall accuracy of MRI was 93%: the method yielded accurate information about size and number of rotator cuff tears, and about bursal, bone and muscle involvement. US accuracy was 83% in the diagnosis of large tears, 63% in the diagnosis of small and partial tears and only 11% in the diagnosis of tendinitis. Both MRI and arthrography exhibited high accuracy (respectively 91 and 100%) in the detection of rotator cuff tears when their results were compared with surgical findings. A flow chart to be used in the patients with acute or chronic shoulder pain was drawn from the critical analysis of the above results.

Arthrography↗
PubMedDate not supplied

[Ozone therapy in lumbar sciatic pain].

INTRODUCTION: Medical ozone is a mixture of oxygen and ozone which can be used for several medical applications. Ozone was first applied clinically to the treatment of lumbar sciatic pain peridurally, while Pietrogrande was the first in Italy to report on its intradiscal administration to treat nucleus polposus herniation. On account of these considerations, we have decided to introduce this method in our Institute (I.C.O.T. Latina) as an alternative to surgery in the treatment of lumbar sciatic pain supported by an intradiscal hernia. MATERIAL AND METHODS: September, 1995, to April, 1997, we treated more than 1000 patients with intradiscal ozone infiltration. We prospectively analyzed the first 50 patients, with 6 months' follow-up at least; all of them were preliminarily submitted to clinical examination, electromyography, CT and MRI. After local anesthesia, we injected the disk, with 18-20 G needles and under CT or fluoroscopic guidance, with 12 ml of a mixture of oxygen and ozone at a concentration of 20-30 micrograms/ml. The treatment was repeated two or three more times at intervals of 3, 15 or, when necessary, 30 days. After each treatment, CT follow-ups were carried out and the final follow-up was made 3 months later. RESULTS: We divided our results into clinical and instrumental. As for clinical response, we had 68% positive results (40% excellent, 28% good) and 32% negative results (10% of patients underwent surgery and 22 are under medical and physical treatment). As for CT response, we had 82% positive results (36% excellent, 46% good), while no major changes between pre- and post-treatment CT findings in the remaining 18% of cases. CONCLUSIONS: Ozone therapy, thanks to its ease of execution and noninvasiveness, permits the successful outpatient treatment of lumbar sciatic pain. Moreover, the lack of major complications and the good results obtained compared to other methods, such as chemonucleolysis, percutaneous automated discectomy, microsurgery and conventional surgery, suggest that ozone therapy can be considered the treatment of choice for lumbar sciatic pain and a valid alternative to surgery in many cases.

Adult↗