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Biomedical subjects

R Sala

Publications and source records attributed to R Sala.

At least 91 records · Page 5Linked to original sources
PubMed1984

New derivatives of pyrrolo and pyrido[2,1-b] quinazoline as antiulcer agents.

A series of 3-benzylidene-1,2,3,9-tetrahydro-9-oxopyrrolo-[2,1-b] quinazolinecarboxylic acids and 6-benzylidene-6,7,8,9-tetrahydro-11-oxo-11H-pyrido[2,1-b] quinazolinecarboxylic acid was synthesized and evaluated for their antiulcer activity by the test of inhibition of restraint ulcers in the rat, and for gastric antisecretory activity using the technique of Shay. Some compounds appear potentially useful for therapeutic application.

Animals↗
PubMed1983

Glucose interorgan exchange in chronic renal failure.

The mechanisms responsible for the altered glucose metabolism observed in chronic renal failure (CRF) were investigated in the postabsorptive state. In 11 patients with CRF and in 15 subjects with normal renal function, the hepato-splanchnic (HS), leg, and brain exchanges of glucose were measured; the HS exchange of gluconeogenic amino acids was also evaluated. Patients with CRF had normal glucose levels, whereas insulin levels and the ratio of insulin to glucose were significantly increased in comparison with controls. In CRF, HS glucose output was slightly lower in comparison with controls (0.46 +/- 0.04 vs. 0.57 +/- 0.04 mmoles/min X 1.73 m2 in controls; P less than 0.1). Arterial levels of alanine and glycine and their uptake by the HS bed were similar in both groups, but in CRF HS serine uptake disappeared, mainly as a consequence of a reduction of its fractional extraction. Conversely, a significant proline extraction became evident, primarily depending on the increased arterial levels of this amino acid. The total HS uptake of potential gluconeogenic amino acids was not different in the two groups, and its ratio to glucose output was increased in CRF (28.0 +/- 4.7 vs. 16.0 +/- 1.9 in controls). In CRF, the arterial-femoral venous differences of glucose were significantly reduced (0.11 +/- 0.04 vs. 0.25 +/- 0.04 mmoles/liter in controls), as was the fractional extraction of glucose in the leg. Finally, in CRF both glucose uptake and its fractional extraction by the brain were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1982

[Scintigraphic examination of the skeleton in renal transplantation].

The authors develop an interesting subject: "Uremic osteodystrophy" in patients who have undergone a kidney transplantation. The analysis of results of bone scan in these patients bears an important contribution to a physiopathology problem that will become more and more important with the progress of transplantation technics.

Adolescent↗
PubMed1981

[Activity of renal enzymes producing ammonia from glutamine in the absence of phosphate in the rat: 1. Effect of chronic metabolic acidosis].

Phosphate- independent glutaminase (PIG) and gamma-glutamyl transpeptidase (gamma GT) activities were evaluated in renal cortex homogenates of rats under normal acid-base balance or chronic metabolic acidosis (CMA). An incubation medium containing glutamine 2 mM, no phosphate, pH 7,40, was used. PIG activity was measured as glutamate production and total gamma GT activity as ammonia production. In normal rats gamma GT activity was significantly higher (0,84 +/- 0,05 mumol/min/g wet wt.) than PIG activity (0,48 +/- 0,06 mumol/min/g wet wt.) (p less than 0,01). In CMA there was a significant increase in PIG activity and an even higher increase in gamma GT activity (p less than 0,01 compared to controls in both cases). The glutamate production/ammonia production ratio was 0,57 +/- 0,05 in normal rats, and 0,37 +/- 0,03 in CMA ( p less than 0,025). These data suggest that the increase in PIG activity and, to a further extent, the increase in gamma GT activity may play an important role in augmenting renal ammonia production in CMA.

Acidosis↗
PubMed1981

[The lipoproteic state in patients with coronary heart disease (author's transl)].

The lipoproteic state of 28 patients with coronary heart disease (CDH) and 44 normal subjects (total N. 72) has been analyzed. In normal subjects the results showed an increase of triglyceride (TG), VLDL with age. For subjects between 20 and 40 years of age, higher values of HDL and lower RF were observed in women than in men. In CHD patients, between 40 and 60 years, higher values of total cholesterol (TC) were observed in women than in men (p less than 0,05). The comparison between male CHD patients and normal male subjects indicated a reduction of HDL and an increase of the risk factor (RF) (p less than 0,05) in coronary patients. However, the female patients showed lower levels of HDL in combination with higher values of TC, LDL, RF, and TG when compared with the control group.

Adult↗
PubMed1980

[Aneurysms of the Valsalva sinus. Study of ten treated subjects (author's transl)].

The study includes 10 patients affected by aneurysm of Valsalva sinus who underwent surgery. The aneurysm involved the "non coronary" sinus in 5 cases and the right coronary sinus in 5. All the aneurysms prolapsed into the right cardiac chambers. Additional cardiac anomalies were present in 6 patients. 4 patients were asymptomatic, 2 were in NYHA class III and 4 in class IV and one was in cardiogenic shock. Indications for surgery were hemodynamic impairment due to the shunt and/or associated anomalies. Surgical treatment included resection of the aneurysm, suture of its orifice and correction of associated cardiac anomalies. Death only occurred in one patient, who arrived at surgery in cardiogenic shock. 8 patients were followed-up for a mean period of 40 months (range 11 to 84 months), after operation: satisfactory clinical conditions were found in all of them. A mild aortic regurgitation was only observed in one patient, 8 years after surgery.

Adolescent↗
PubMedDate not supplied

The Pleistocene site of Gran Dolina, Sierra de Atapuerca, Spain: a history of the archaeological investigations.

Gran Dolina is part of an archaeological and paleontological complex located in the Sierra de Atapuerca karstic system (Burgos, Spain). The Trinchera del Ferrocarril sites were discovered as a consequence of the construction of a railway for the transport of minerals at the end of the nineteenth century. The systematic excavation of the upper Gran Dolina levels was initiated in 1981. In 1993, a 6 m(2)biostratigraphic survey pit was started, reaching level TD6 in 1994. This level was excavated during four consecutive years, yielding human fossils, identified as Homo antecessor, in association with lithic and faunal remains, dating to more than 0.78 m.y.a.

Animals↗
PubMedDate not supplied

The TD6 (Aurora Stratum) hominid site. Final remarks and new questions.

The study of the faunal and lithic assemblage (including almost a hundred human fossil remains) recovered from the Aurora stratum-TD6 level of the Lower Pleistocene cave site of Gran Dolina (Sierra de Atapuerca, Spain) has allowed us to answer some important questions concerning the debate about the earliest evidence for human occupation of Europe. However, it has also started new discussions about some geographical, ecological, and economic aspects of this earliest occupation. The nature (definitive or ephemeral) of the first occupation, as well as the model for the arrival of the Acheulean (Mode 2) in Europe are also issues for discussion.

Animals↗
PubMedDate not supplied

The TD6 level lithic industry from Gran Dolina, Atapuerca (Burgos, Spain): production and use.

Technological analysis of lithic artefacts recovered at the Aurora stratum of Atapuerca-TD6 shows that this Lower Pleistocene assemblage is similar to Mode I Technology (=Oldowan tradition) documented at many African sites. Diachronic comparison of the different levels of Gran Dolina allows us to conclude that this particular form of early European technology lacks the production of big flakes to manufacture large tools such as bifaces and cleavers. Rather, it is characterized by the presence of small artefacts, including flakes, denticulates, notches, and side-scrapers, many of which bear use-wear traces of butchery and woodworking. The dominant production technique is orthogonal, which is also reflected in the core recovered at the slightly older level of TD4. The raw materials also found in the Middle Pleistocene occupations at Atapuerca, though with significant proportion differences, have a local origin and include varieties of flint, quartzite and sandstone as well as limestone and quartz. TD6 small artefacts were made from most of these, although the retouched pieces seem to have been preferentially made of the best quality flint, i.e., Cretaceous flint, pointing to the existence of differential use of lithic material, and therefore, some degree of planned knapping behaviour. Most of the "chaînes opératoires" or reduction sequences took place inside the cave, although some artefacts, elaborated on Cretaceous flint, seem to have been retouched off site, possibly near the supply sources.

Animals↗
PubMedDate not supplied

The role of system A for neutral amino acid transport in the regulation of cell volume.

System A is a secondary active, sodium dependent transport system for neutral amino acids. Strictly coupled with Na,K-ATPase, its activity determines the size of the intracellular amino acid pool, through a complex network of metabolic reaction and exchange fluxes. Many hormones and drugs affect system A activity in specific cell models or tissues. In all the cell models tested thus far the activity of the system is stimulated by amino acid starvation, cell cycle progression, and the incubation under hypertonic conditions. These three conditions produce marked alterations of cell volume. The stimulation of system A activity plays an important role in cell volume restoration, through an expansion of the intracellular amino acid pool. Under normal conditions, system A substrates represent a major fraction of cell compatible osmolytes, organic compounds that exert a protein stabilizing effect. It is, therefore, likely that the activation of system A represents a portion of a more complex response triggered by exposure to stresses of various nature. Since system A transporters have been recently cloned, the molecular bases of these regulatory mechanisms will probably be elucidated in a short time.

Amino Acid Transport Systems↗
PubMedDate not supplied

The role of the neutral amino acid transporter SNAT2 in cell volume regulation.

Sodium-dependent neutral amino acid transporter-2 (SNAT2), the ubiquitous member of SLC38 family, accounts for the activity of transport system A for neutral amino acids in most mammalian tissues. As the transport process performed by SNAT2 is highly energized, system A substrates, such as glutamine, glycine, proline and alanine, reach high transmembrane gradients and constitute major components of the intracellular amino acid pool. Moreover, through a complex array of exchange fluxes, involving other amino acid transporters, and of metabolic reactions, such as the synthesis of glutamate from glutamine, SNAT2 activity influences the cell content of most amino acids, thus determining the overall size and the composition of the intracellular amino acid pool. As amino acids represent a large fraction of cell organic osmolytes, changes of SNAT2 activity are followed by modifications in both cell amino acids and cell volume. This mechanism is utilized by many cell types to perform an effective regulatory volume increase (RVI) upon hypertonic exposure. Under these conditions, the expression of SNAT2 gene is induced and newly synthesized SNAT2 proteins are preferentially targeted to the cell membrane, leading to a significant increase of system A transport Vmax. In cultured human fibroblasts incubated under hypertonic conditions, the specific silencing of SNAT2 expression, obtained with anti-SNAT2 siRNAs, prevents the increase in system A transport activity, hinders the expansion of intracellular amino acid pool, and significantly delays cell volume recovery. These results demonstrate the pivotal role played by SNAT2 induction in the short-term hypertonic RVI and suggest that neutral amino acids behave as compatible osmolytes in hypertonically stressed cells.

Adaptation, Physiological↗
PubMedDate not supplied

New localization technique for breast cancer biopsy: mammotome guidance with imaging probe.

AIMS AND BACKGROUND: The "Imaging Probe" (IP) is a small, portable, high-resolution gamma camera to be used in radioguided surgery. The present work discusses a special prototype designed for guiding biopsies. The IP was mounted to a Fischer digital X-ray stereotactic core biopsy system in such a way that biopsy could be guided simultaneously by X-ray stereotaxis and 99mTc-Sestamibi (MIBI) images from IP. METHODS: The IP field of view was 22.8 x 22.8 mm(2), with a spatial resolution of approx. 2.5 mm. We used off-line software for image fusion on a dedicated Pentium III portable PC. It was matched with a Fischer digital X-ray stereotactic biopsy system dedicated to direct the mammotome towards breast opacities. The operator was allowed to slightly correct the direction of the mammotome needle taking into account stereotactic X-ray, scintigraphic and fused images. Biopsy samples were counted by IP before they were sent to the pathologist. RESULTS: High-resolution IP scintigraphy showed substantial, though not exact, matching between MIBI hot spots and X-ray opacities. More than one hot spot was detected even in the smallest (0.6 cm) lesion. Post-biopsy scintigraphy showed absence of significant hot spots in two patients, whereas in the third patient one of the three hot spots was still partially present. All lesions showed cancer on histological examination. CONCLUSIONS: Measurement of radioactivity in biopsy specimens confirmed the heterogeneous distribution of radioactivity within cancers that IP had detected before biopsy.

Biopsy, Needle↗
PubMedDate not supplied

[Study of factors affecting the renin-angiotensin-aldosterone system in the premature infant].

Renin-angiotensin-aldosterone system (RAA), Na-K dietary intake and Na-K urinary excretion in 36 premature babies have been investigated. The plasmatic renin activity (PRA) and plasmatic aldosterone level (P-aldo) resulted significantly increased in comparison with children previously studied, 20 days - 23 months old (p less than 0,01). P-aldo demonstrated, in premature babies, a negative correlation with Na-K intake and urinary excretion (p less than 0,001 and less than 0,01 respectively); in the groups nourished with maternal milk or "adapted" formulae P-aldo mean value was significantly more elevated than in the group nourished with formulae "unadapted" (p less than 0,01). A different Na dietary intake seems to be the most important factor influencing P-aldo level also in premature babies. No correlation between PRA - electrolyte excretion was found in any group. The main factor influencing PRA seems to be the age of infants as well as, probably, other hemodynamic mechanisms.

Humans↗
PubMedDate not supplied

Evaluation of some benzyl and benzylidene monosubstituted gamma-butyrolactones and tetrahydrofurans as platelet activating factor antagonist agents.

Some benzyl and benzylidene monosubstituted gamma-butyrolactones and tetrahydrofurans were applied as platelet activating factor (PAF) antagonist agents. The results indicated that, whereas all benzyl derivatives are completely inactive, benzylidene substitution is the key feature for obtaining moderate activity. Molecular modeling and molecular electrostatic potential mapping are applied in conjunction with the most recent PAF-receptor model to rationalize the results.

4-Butyrolactone↗