Search PubMed⌕ Search

Biomedical subjects

A Scarpa

Publications and source records attributed to A Scarpa.

At least 307 records · Page 17Linked to original sources
PubMedDate not supplied

A new method for monitoring the kinetics of calcium binding to the sarcoplasmic reticulum Ca(2+)-ATPase employing the flash-photolysis of caged-calcium.

The kinetics of Ca2+ binding to the high-affinity sites of the sarcoplasmic reticulum (SR) Ca2(+)-ATPase were directly investigated by continuously monitoring the extravesicular calcium concentration via the metallochromic indicator Arsenazo III following the release of Ca2+ from a photolabile caged-calcium molecule, 1-(2-nitro-4,5-dimethoxyphenyl)-N,N,N',N'-tetrakis [(oxycarbony)methyl]-1,2-ethanediamine (DM-nitrophen), utilizing a pulsed Nd:YAG laser for photolysis. The nature of the binding kinetics is at least biphasic over the first 400 ms for vesicular dispersions of SR. The stoichiometry for calcium binding expressed as Ca:E1 approximately P has been calculated to be approximately 1.4:1 for the pure SR preparation under the reaction conditions employed.

Acetates↗
PubMedDate not supplied

Substance P and mitochondrial oxygen consumption: evidence for a direct intracellular role for the peptide.

Substance P (SP), a member of the tachykinin group of peptides, has been shown to augment the sensory discharge of the carotid body, an oxygen sensing chemoreceptor. In this study we present evidence that the excitatory effect of SP, in part, could arise from a direct effect of the peptide on mitochondrial oxidative phosphorylation. Measurement of the partition coefficient of SP showed that the peptide has a relatively high apolar partition, which could be consistent with its distribution across lipid bilayers and in intracellular organelles. In addition, the effects of three concentrations of SP were tested on oxygen consumption of mitochondria isolated from rat hearts. The results showed that while the lower concentration of the peptide (0.5 microM) did not affect O2 consumption, higher concentrations, i.e., 1 and 2 microM, enhanced the rate of state 4 respiration by 52 and 64%, respectively. The rate of state 3 respiration, on the other hand, was unaltered with 0.5 and 1 microM, and was only slightly decreased with 2 microM of the peptide. The ADP:O ratio was unaffected by any concentrations of SP tested. The peptide-induced effect on state 4 respiration was even more pronounced with glutamate as a respiratory substrate and in presence of K+ in the medium. These results indicate that SP, in addition to its more accepted role as a neurotransmitter or modulator in the carotid body, may elicit intracellular response by interfering directly with oxidative phosphorylation.

Adenosine Diphosphate↗
PubMedDate not supplied

Depigmenting procedures and drugs employed by melanoderm populations.

The "fashion" of lightening the skin represents a very serious problem because it involves the melanoderm populations, not only in Africa, but in the world, undermining their physical integrity and psychological equilibrium. The diffusion of the skin-whitening practice is much more intense in the areas where there are inter-relations between Blacks and Whites. Among the drugs used, mercury prevails under the form of biioduro salts in aseptic soaps; hydroquinone taken in form of per os pills, and cortisoides. The resource of using traditional skin-bleaching plants seems frequent, but the information we tried to gather from informants has been very scarce.

Africa↗
PubMedDate not supplied

[Advanced gastric adenocarcinoma with RER+ phenotype presents a good prognosis after 5 years of curative resection].

Microsatellite instability (MIN) has been found both in advanced and early gastric cancer. To find out the step played by MSI in gastric carcinogenesis, links between RER+ phenotype and clinical and pathological aspects have been studied. In this work our purpose is to analyze the relationship between MIN+ advanced gastric cancer and prognosis at 5 years after radical surgery. We investigated 34 patients affected by gastric cancer who underwent R0 surgical resection from February 1991 to October 1994. After that, they underwent a four-monthly follow-up for a minimum of 5 years. Genetic abnormalities have been searched including (a) those occurring in common-type CIN carcinomas and (b) those characteristic of MIN cancers. DNA extraction showed the presence of microsatellite instability (MIN) in 9 (26%) of the samples (vs. 74% of chromosomal instability CIN); none of them was M+ (vs. 12% of CIN cancers). Recurrence occurred in 2 out of 9 of the MIN cancers (22%) and in 21 out of 25 CIN cancers (84%). In conclusion, our data suggest that advanced gastric cancers with mutator phenotype show a better outcome at 5 years than the CIN phenotype.

Adaptor Proteins, Vesicular Transport↗
PubMedDate not supplied

[Not Available].

Explore the source record for details and available documents.

History, Ancient↗
PubMedDate not supplied

Analysis of the methylation pattern of c-Ha-ras oncogene in human prostatic cancer.

To determine the methylation pattern of c-Ha-ras oncogene in prostatic tissue and to identify possible changes of methylation associated with cancer, high molecular weight DNA was extracted from 7 normal and 6 carcinomatous human prostates. Analysis of the samples was performed by cleaving DNA with the restriction endonucleases Msp I, Hpa II and Cfo I, and by Southern hybridizing the DNA digests with the 32P-labelled c-Ha-ras (pT24-C3) probe. Several discrete fragments were obtained with Hpa II and Cfo I digestion while the Msp I pattern showed fewer and smaller bands. Therefore, c-Ha-ras appears to be partially methylated. While a considerable polymorphism of the sequence 5'-CCGG-3' was observed at several Msp I sites in all cases, no significant differences could be evidenced in the methylation patterns of normal and neoplastic prostatic DNA samples extracted and purified from each patient.

DNA, Neoplasm↗