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Biomedical subjects

A Prieto

Publications and source records attributed to A Prieto.

At least 109 records · Page 6Linked to original sources
PubMed1993

Diminished DNA synthesis in T cells from B chronic lymphocytic leukemia after phytohemagglutinin, anti-CD3, and phorbol myristate acetate mitogenic signals.

T lymphocytes from patients with B cell chronic lymphocytic leukemia (B-CLL) exhibit defective proliferative response to plant lectins. The blastogenic response of purified T lymphocytes to signals that interact with membrane molecules (phytohemagglutinin [PHA], anti-CD3 monoclonal antibody [MAB]) and with the intracytoplasmic protein kinase C (PKC) was investigated in 22 B-CLL patients and 18 healthy controls. 3H-thymidine uptake in T lymphocytes from 14 of 22 B-CLL patients after PHA, anti-CD3, and phorbol myristate acetate (PMA) was found to be lower than in the healthy controls. This defective proliferative response was not corrected by the exogenous addition of interleukin-2 (IL-2) to the culture medium. In analyzing the cell cycle progression of these T lymphocytes from B-CLL patients, we found that the percentage of cells in S phase at 2 days of PHA stimulation was significantly decreased and that it was normalized after 5 days of culture. Defective response of T lymphocytes from B-CLL patients to polyclonal mitogens was observed in those patients with advanced disease (stages A, B, and C). However, this T cell proliferative response was normal in patients with "smoldering B-CLL." We conclude that the defective proliferative response to membrane and intracytoplasmatic mitogenic signals on T lymphocytes from a part of B-CLL patients can be ascribed to delayed activation and cell-cycle progression, and an association between the alterations in the T cell compartment of B-CLL patients and the progression of the disease may be suggested.

Aged↗
PubMed1992

Purification of a new galactanase from Penicillium oxalicum catalysing the hydrolysis of beta-(1----5)-galactofuran linkages.

An endo beta-(1----5)-galactofuranase from Penicillium oxalicum has been purified 91-fold. The enzyme is a basic glycoprotein with a pI 7.9 and 20% (w/w) carbohydrate content, galactose being the principal sugar. The apparent Mr of the enzyme estimated by denaturing gel electrophoresis was 77,000. The optimum pH was 5.0, and the enzyme was stable over the pH range 4.0-7.5. This enzyme hydrolyses specifically (1----5)-linked beta-D-galactofuranose residues in homo- and heterogalactans, but did not hydrolyse o-nitrophenyl galactose and beta-(1----5)-galactofuranbiose. Km and Vmax. values were 1.2 mg.ml-1 and 0.55 mumol.h-1 respectively when Eupenicillium crustaceum beta-(1----5)-galactofuran was used as substrate. The enzyme showed high affinity for different separation gels and proteins. The enzyme specificity and its mode of action showed that it could be an useful tool for analysing the fine structure of polysaccharides.

Carbohydrate Conformation↗
PubMed1992

Chemical and structural similarities in wall polysaccharides of some Penicillium, Eupenicillium and Aspergillus species.

Various fractions were extracted from cell-wall material of Eupenicillium crustaceum, Penicillium brevi-compactum, P. decumbens, Aspergillus flavipes and A. ochraceus. The most characteristic fractions, which may have chemotaxonomic relevance, were F1I, an alpha-(1-3) glucan (alkalisoluble, water-insoluble), which amounted to 16.2-32.5% of the cell-wall material, and F1S (alkali and water-soluble) which represented 2.5-6.2% of the cell-wall material and was identified as a beta-(1-5) galactan. 13C-NMR spectra of the F1S fractions showed the same pattern for all the fungal species, characteristic of beta-(1-5) linked galactofuranose.

Aspergillus↗
PubMed1992

Sinus pericranii: radiological and etiopathological considerations. Case report.

Sinus pericranii is a rare vascular anomaly involving an abnormal communication between the extracranial and intracranial circulations. A case of frontal sinus pericranii is presented which appeared to be a posttraumatic sinus because it developed 2 years after a cranial injury. However, the presence of vascular endothelium in the pathological examination and its association with a vascular anomaly (persistent trigeminal artery) suggested a congenital origin. The lesion, pericranial blood sinuses, and bone were totally removed. The computerized tomography, angiography, and magnetic resonance imaging findings are presented. The literature is reviewed and the pathogenesis of sinus pericranii is discussed.

Adult↗
PubMed1990

[Blood transfusion worsens the prognosis in colorectal cancer. Preliminary study in a series of 717 cases].

We have conducted an investigation on the relationship between blood transfusion and recurrence of resected colorectal cancer and survival of the patients. During the past ten years 717 patients have been surgically treated of colorectal cancer in our hospital; 442 of the cases were Duke's stages B or C, and the resection had been considered radical. In both groups, recurrences were most frequent in patients who received blood transfusions; survival was also lower in this group of patients.

Adenocarcinoma↗
PubMed1988

Extracellular galactosaminogalactan from Penicillium frequentans.

Penicillium frequentans secreted an exopolysaccharide composed mainly of N-acetyl-galactosamine (48.4%) and galactose, mannose and glucose in the ratio 4:1:1, that were alpha - (1----4) and alpha - (1----3) linked predominantly. Greater polysaccharide production was achieved in old cultures grown statically with glucose as carbon source.

Carbohydrate Metabolism↗
PubMed1985

Substrate-level energy dependence of acid secretion in the isolated human gastric mucosa.

The substrate-level energy dependence of acid secretion was investigated in the human gastric mucosa in vitro using biopsy specimens obtained during fiberoptic gastroscopy in symptomatic patients. The oxygen consumption and the accumulation of aminopyrine were used as indexes of secretory activity. Basal and histamine-stimulated oxygen uptake by fundic biopsy specimens were not affected by medications (pethidine and diazepam) administered during gastroscopy. Under substrate-depleted conditions, the oxygen consumption and the aminopyrine accumulation of fundic mucosa were not significantly increased by histamine. Stimulation of functional activities by gastric secretagogues was observed only in the presence of exogenous substrates. The ability of various substrates to support acid formation in the presence of gastric secretagogues was evaluated. Carbohydrates were found to be effective substrates in supporting the functional responses of the tissue, with glucose being the most effective. Propionate, butyrate, beta-hydroxybutyrate, and octanoate were ineffective as substrates. Glucose by itself, but not butyrate, significantly increased oxygen uptake and aminopyrine accumulation. The results suggest that the human gastric mucosa, in vitro, has an absolute requirement for metabolic substrates to support secretory responses and that carbohydrates seem to be the preferential substrates.

Adolescent↗
PubMed1985

Hypercalcemia in association with cutaneous squamous cell carcinoma. Occurrence as a late complication of hidradenitis suppurativa.

Squamous cell carcinoma of the skin is a rare complication of hidradenitis suppurativa. We treated a case of hidradenitis-associated squamous cel carcinoma with metastases to the inguinal lymph nodes. Hypercalcemia also occurred, possibly in relation to the secretion of a hormonelike substance by the tumor. Chemotherapy with bleomycin sulfate, methotrexate sodium, and cisplatin led to tumor regression and control of the hypercalcemia.

Adult↗
PubMed1967

Electrical recordings from meningioma cells during cytolytic action of antibody and complement.

Resting membrane potential and total cell resistance of human meningioma cells in tissue culture have been measured with fine microelectrodes. Addition of either antiserum inactivated with heat or control serum from normal rabbits produced small depolarizations (2 to 4 millivolts) with no discernible ( 5 percent) change in resistance. Addition of antiserums with complement, however, produced larger depolarizations and decreases in resistance before any changes in cell morphology were visible with light microscopy; as cytoplasmic swelling progressed, membrane potential dropped close to zero, and resistance decreased five- to tenfold. The electrical recording technique may be useful in the study of sublethal as well as lethal damage to immune cells and, in particular, may permit temporal resolution of damaging events and repair mechanisms in a single cell.

Antibodies↗