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R Vanni

Publications and source records attributed to R Vanni.

At least 73 records · Page 4Linked to original sources
PubMed1986

A possible correlation between DA-DAPI counterstaining and alu I-induced bands in fixed human chromosomes.

DA-DAPI counterstaining is a technique which reveals the heterochromatic areas of chromosomes 1, 9, 15, 16 and Y in humans; a result which may be related to the peculiar characteristics of these chromosomal regions, particularly regarding their DNA content. The present report describes a different DA-DAPI stain reaction. Obtained under standard conditions, it shows positive, bright staining in a large number of chromosomes. Such a result is discussed in relation to the banding pattern produced by Alu I in human metaphase chromosomes, in view of the high degree of overlapping of the two patterns.

Chromosome Banding↗
PubMed1985

Derivative 11 marker chromosome in bladder carcinoma.

Cytogenetic studies on bladder carcinomas from two patients were carried out on preparations obtained by a direct method. The chromosome mode was 49 and 55, respectively. Several karyotypic changes were found in the tumors. Moreover, the analysis of Q-banded chromosomes revealed the presence in both cases of a chromosome 11p+. These rearranged chromosomes showed a very similar banding pattern. The finding of a der(11) chromosome marker in two patients is intriguing, and suggests the possibility of nonrandom chromosome changes in bladder carcinoma, as already found in other kinds of tumors. The occurrence of chromosome #11 aberrations in tumors of the urinary tract is discussed in connection with the current theories on oncogenesis.

Aged↗
PubMed1985

Some factors affecting the action of restriction endonucleases on human metaphase chromosomes.

We have investigated whether restriction endonucleases produce bands on human chromosomes by extracting DNA, using staining methods which are stoichiometric for DNA. Restriction enzymes that produce C-band patterns appear to remove DNA extensively from chromosome arms. In general, however, those restriction enzymes that produce G-bands do not extract DNA from chromosomes, and their effects are believed to be due to conformational change in the chromosomal DNA; in these cases, the chromosomal regions affected appear to be determined by the chromosome structure and not by the specificity of the enzyme. DNA loss from chromosomes due to digestion by restriction enzymes may in some cases be uniform, although a G-banding pattern is visible after Giemsa staining.

Azure Stains↗
PubMed1985

Thermal haemolytic threshold of human erythrocytes.

Haemolytic thermal threshold of human erythrocytes has been determined by means of an especially designed microwave apparatus. Temperatures between 50 and 55 degrees C are necessary to produce an initial haemolysis of erythrocytes in the whole blood, while the thermal threshold drops to 37 degrees C for red blood cells suspended in buffered saline. Absorbed energy measurements permit the conclusion that the haemolytic effect is thermal in nature.

Erythrocytes↗
PubMed1985

S1 nuclease removes DNA from eukaryotic metaphase chromosomes: cytological evidence.

Fixed and unfixed human chromosomes, as well as fixed rye chromosomes were treated with S1 nuclease, which specifically cleaves single stranded DNA. Subsequent staining with either acridine orange, ethidium bromide or Giemsa revealed that, contrary to what has previously been reported, S1 digestion extensively altered chromosomal morphology and staining intensity, although the alteration was more pronounced in fixed as compared to unfixed metaphases. A number of mechanisms, which may account for our findings, have been invoked: a) the presence in metaphase chromatin of B-DNA/Z-DNA transitional junctions, b) the induction, by alcohol: acid fixation procedure, of nicks within regular B-DNA conformation and c) the induction of sites available to S1 by torsional stress due to metaphase high condensation degree.

Chromatin↗
PubMed1983

Chromatin organization and restriction endonuclease activity on human metaphase chromosomes.

Human metaphase chromosomes were treated with HaeIII, HindIII, EcoRI, and AluI restriction endonucleases and subsequently stained with either Giemsa or ethidium bromide. The results obtained seemed to suggest that the structural organization of specific chromosome regions can play a primary role in determining the cytological effect after digestion with specific restriction endonucleases.

Azure Stains↗
PubMed1983

Selective digestion of human metaphase chromosomes by Alu I restriction endonuclease.

Human cytological preparations have been digested with Alu I restriction endonuclease (Endo R Alu I) and subsequently stained with acridine orange. Metaphase chromosomes treated in this way revealed a clear-cut bright/ dull longitudinal differentiation. It has been postulated that these cytological findings could be related to the selective digestion, by Alu I, of all DNA with the exception of some heterochromatic, possibly satellite, fractions.

Chromosomes, Human↗
PubMed1982

A radio-frequency monitor for protection against overexposure from RF heaters.

Extensive investigation on the various potentially polluting RF sources has led to the conclusion that the largest proportion of problems arising from possible RF hazards originates from industrial heating machines (short-wave). In particular, these turn out to require checks due to their intrinsic and induced instabilities. Through the analysis of RF leakage characteristics of these machines, the problem is simplified and the solution is presented in terms of an RF hazard monitor which can be used by non-specialized personnel. The monitor is also suitable for several other types of potentially dangerous apparatus in the medium- and short-wave range.

Environmental Exposure↗
PubMed1981

Preferential maternal derivation in inv dup(15): analysis of eight new cases.

Eight patients are reported with a de novo extra inverted duplicated chromosome 15. The abnormal chromosome was considered to be the same in all cases, but its precise delineation remained uncertain and was defined as either 15pter leads to 15q12::15q12 leads to 15pter or 15pter leads to 15q11::15q13 leads to 15pter. Analysis with various techniques of the satellite regions of the bisatellited chromosomes demonstrated maternal derivation in six and paternal derivation in one of the seven families. A non-sister chromatid exchange between the two homologous chromosomes 15 is considered a likely origin of the inv dup(15) in the cases with maternal derivation; in the only case of paternal derivation, however, the abnormal chromosome originated from one single chromosome 15. The clinical findings confirm that patients with inv dup(15) have mental and developmental retardation and are frequently affected by seizures, while severe physical malformations are absent.

Abnormalities, Multiple↗
PubMed1980

Trisomy 16q21 = to qter.

A case of trisomy 16q secondary to a paternal 16/18 translocation is described. A comparison of this case with the few other cases of trisomy 16q described in the literature indicates that trisomy for the long arm of chromosome 16 results in a severely affected phenotype and early death. Conversely, patient with trisomy 16p do not have gross abnormalities. We postulate that the prenatal lethality of full trisomy 16 is mainly due to the trisomy for the long arm.

Abnormalities, Multiple↗
PubMedDate not supplied

Diagnosis of chromophobe renal cell carcinoma by chromosomal analysis.

Chromophobe renal cell carcinoma may pose a differential diagnostic problem by routine histologic examination because it may be misdiagnosed as another type of renal cancer with a totally different clinical behavior. A low DNA content as well as hypodiploidy seem to be associated with this renal tumor subtype. We report a case in which the cytogenetic report was of great value for a correct histologic diagnosis.

Carcinoma, Renal Cell↗
PubMedDate not supplied

Phantom characterization of applicators by liquid-crystal-plate dosimetry.

A method for the determination of the SAR distribution produced by an electromagnetic applicator for localized hyperthermia is described. The procedure for SAR evaluation consists of recording the time evolution of the temperature inside a polyacrylamide phantom by means of thermochromic liquid crystal sheets inserted in it. The technique allows a complete characterization of applicators in a very broad frequency range, using power levels of the order of those needed in real treatments. Criteria for the minimum phantom size and the maximum time duration of the characterization procedure are indicated, which allow a reliable determination of the effective field size and penetration depth of the applicator.

Biophysical Phenomena↗