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Biomedical subjects

M Ortega

Publications and source records attributed to M Ortega.

At least 19 recordsLinked to original sources
PubMed1992

[Cystic neoplasm of the pancreas as a cause of intestinal obstruction].

Cystic neoplasms of the pancreas are unusual varieties of pancreatic tumors. We herein report a new case presenting with atypical features, such as mental and electrolytic disturbances secondary to upper intestinal obstruction. We reviewed the literature, and discuss the differential diagnosis, the histopathological characteristics of prognostic value, and the therapeutic strategy. We conclude that these tumors should be included in the differential diagnosis of the upper intestinal obstructions, and emphasize the need to remove the lesion in all cases because of the difficulties of predicting the benign or malignant behaviour of these tumors before and during the surgical procedure.

Cystadenocarcinoma↗
PubMed1991

Cloning of coliphage-T4 gene pseT and high-level synthesis of polynucleotide kinase in Escherichia coli.

The gene, pseT, of coliphage T4 which encodes polynucleotide kinase (PNK) was cloned directly into an expression plasmid using the polymerase chain reaction. When placed under the control of the trp promoter, the pse T gene can be maintained stably in Escherichia coli and yields high levels of the enzyme upon induction. The system described facilitates purification and provides very high yields of PNK.

Base Sequence↗
PubMed1991

[Endogenous digitalis].

During the past 10 years, several groups of researchers from different laboratories have carried out research on an endogenous substance or substances which had cross immunoreacted to digoxin antibodies in patients without previous cardiotonic treatment. The increase has been demonstrated in various clinical cases which involve an augmentation of plasmatic volume. A considerable amount is known about its molecular structure and anatomic origin; the competitive inhibition of the sodium pump being quite clear.

Animals↗
PubMed1991

[AM3 (a biological response modifier) in the treatment of recurrent aphthous stomatitis. Clinical evaluation and preliminary studies on NK (CD16) cells and their pathogenic role in the syndrome].

In an open-controlled trial--oral washes (20 patients) versus test (19 patients)--, we have studied the effects of AM3 (a new oral BRM) on clinical evolution of the recurrent stomatitis (RAS) syndrome. The results obtained at 6th month showed significant decreases on ulcer numbers (p less than 0.001) as well as in their mean duration time (p less than 0.001) due to the AM3 treatment. From a pathophysiologic point of view, the study of the NK peripheral blood cells (Leu 11/CD16) suggests the existence of two kinds of RAS-patients: those showing normal NK cell numbers (approximately 33%) and those ones showing a partial lack in the NK numbers (approximately 67%). These results suggest different rational new approaches to treatment, based on new pathophysiological concepts.

Adolescent↗
PubMed1987

Atrial natriuretic peptide (ANP), guanylate cyclase, and intraocular pressure in the rabbit eye.

Synthetic rat atrial natriuretic peptide (ANP) was examined for effects on guanylate-and on adenylate cyclase activity in ciliary process homogenates and for effects on intraocular pressure in the albino rabbit eye. Ciliary process guanylate cyclase was associated predominantly with the particulate fraction and was partially activated by ANP (EC50, approximately 1 nM) relative to a maximal dose of Na Nitroprusside (2 uM), whereas particulate adenylate cyclase (basal as well as forskolin-stimulated activity) showed no responses to ANP at doses up to 0.3 uM. Particulate cAMP phosphodiesterase activity was stimulated by low doses of cGMP (1-5 uM) in ciliary processes. Thus, ANP, acting via guanylate cyclase, has the potential to regulate phosphodiesterase activity and indirectly decrease cAMP levels in membranes derived from ciliary processes. Intravitreous injection of ANP (2-4 ug/eye) caused a small decrease (1-1.5 mm Hg) in intraocular pressure measured 16-24 hours after injection but the pressure had returned to normal by 40 hours. The findings demonstrate regulation of biochemical and pharmacological responses by ANP in the albino rabbit eye suggesting that this peptide may play a physiological role in secretory functions of ciliary processes.

Adenylyl Cyclases↗
PubMed1987

Effects of inorganic ions on rabbit ciliary process adenylate cyclase.

The interaction of several inorganic ions (Mn2+, Ca2+, VO3-, and F-) with adenylate cyclase in the albino rabbit ciliary process particulate fraction was studied. Effects of these substances were determined on three activity states of the enzyme (basal, Gs-protein stimulated activity via isoproterenol activation of beta-adrenergic receptors, forskolin-activated catalytic unit) in the presence of 3 mM Mg2+, 1 mM EDTA and 0.2 mM EGTA. A different pattern of effects was found for each of the four ions. Addition of Mn2+ (2 mM) increased all three responses; basal by up to ten-fold, isoproterenol and forskolin by four to five-fold. Added Ca2+ (1 mM) increased basal by two to three-fold, but inhibited isoproterenol and forskolin responses by 25-50%. Added vanadate (1-10 mM) increased basal by two to four-fold, had no effect on the isoproterenol response, but doubled the forskolin response at 3 mM. Added F- (10 mM) increased basal by 30-40-fold, decreased the isoproterenol response and potentiated the forskolin response. The response to F- which directly activates G-proteins was much greater than that of non-hydrolysable GTP analogs, which also directly activate G-proteins. The results suggest that more than one type of adenylate cyclase and/or several modes of regulation of adenylate cyclase with different ionic requirements may be present in ciliary process membranes.

Adenylyl Cyclases↗
PubMed1985

Keratosis punctata of the palmar creases.

A 44-year-old man with no family history of keratosis punctata showed, at the age of 19 years, punctiform hyperkeratotic elements confined exclusively to the flexion creases of the palms and digits. We review the literature and comment on the clinical, histologic, and therapeutic aspects of this exceptional dermatosis.

Adult↗
PubMed1979

Myrtus communis L. phytohemagglutinins as a clarifying agent for lipemic sera.

Phytohemagglutinins from sees of Myrtus communis L., either in solution or adsorbed by glutaraldehyde-treated erythrocytes, constitute an effective system for clarification of lipemic sera. It can be used in clinical analysis to avoid the interference produced by turbidity in spectrophotometric determinations. Parameters such as glucose, bilirubin, urea, uric acid, GPT, GOT, and LDH, amongst others, can be determined without interference. The content in triglycerides of 1 ml of serum can be decreased by more than seventy per cent by treatment with 50 mg of lyophilized glutaraldehyde-treated erythrocytes saturated with Myrtus communis L. phytohemagglutinins.

Erythrocytes↗