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Biomedical subjects

C Salas

Publications and source records attributed to C Salas.

At least 73 records · Page 4Linked to original sources
PubMed1995

[The adult respiratory stress syndrome and septic shock associated with tuberculosis].

The increase in the incidence of tuberculosis infection in the last few years has caused a recurrence of atypical clinical forms, as well as the development of associations and uncommon complications during the clinical course, which include the adult respiratory distress syndrome (ARDS) and septic shock. Three patients with ARDS are here reported; two patients had findings of septic shock and negative serology to human immunodeficiency virus and the only etiological agent documented was M. tuberculosis. The three patients required hemodynamic support and two of them mechanical ventilation. None of the patients survived the episode. Tuberculosis, particularly the disseminated forms, should be considered as possible etiology in high risk patients with septic shock, ARDS or both.

Adult↗
PubMed1995

Properties of laccase isoenzymes produced by the basidiomycete Ceriporiopsis subvermispora.

Laccase is one of the ligninolytic enzymes found in liquid cultures of the fungus Ceriporiopsis subvermispora in defined medium. As an approach to a clarification of the role of laccases during the attack on lignin by the fungus, the enzyme has been characterized further. The levels of this phenol oxidase increase 2-fold in the presence of p-anisidine and are severely affected when addition of either Mn(II) or Cu(II) ions to the medium is omitted. Isoelectrofocusing allowed the resolution of two laccase isoenzymes, with pIs of 3.65 and 3.59. In rich medium, laccase activity is 10-fold higher than in salt medium, and it is not affected by the external addition of p-anisidine or Mn(II). Four isoenzymes were detected in these cultures, with pIs between 3.76 and 3.60. In a wheat bran medium, four isoenzymes with pIs in the range 3.63-3.46, plus a fifth isoenzyme of high pI (4.82), were also identified. The absorption spectrum of a pool containing the four isoenzymes from rich medium shows a maximum at 600 nm, typical of laccase possessing a type I copper atom. The molecular mass of the isoenzyme with pI 3.60 is 79 kDa, as determined by SDS/PAGE. Upon treatment with endoglycosidase F, the molecular mass of this isoform decreases to 63 kDa, indicating a high degree of glycosylation. Substrate specificity studies conducted with the four isoenzymes from rich medium and a combination of isoenzymes from salt medium showed marked differences among them. The amino-terminal sequences (24 residues) of three isoenzymes isolated from rich medium were determined. Two of them are identical, whereas the third one differs from these in three amino acid residues. The consensus sequence reveals clear homology with laccases from other microorganisms.

Amino Acid Sequence↗
PubMed1994

Involvement of ETA receptors in the facilitation by endothelin-1 of non-adrenergic non-cholinergic transmission in the rat urinary bladder.

1. Endothelin-1 (ET-1; 3-10 nM) raised the tone of rat bladders bathed in buffer containing atropine (1 microM) plus guanethidine (3.4 microM). In addition, ET-1 potentiated, in a concentration-dependent fashion (1-10 nM), the contractions evoked by both transmural nerve stimulation and applications of exogenous adenosine 5'-triphosphate (ATP). 2. The threshold concentration of ET-1 required to facilitate non-adrenergic non-cholinergic (NANC) transmission and potentiate ATP-induced contractions, was about 10 fold lower than that required to increase the bladder tone (3 nM). 3. The ET-1-induced increase in basal tension reached its maximal effect within 60-90 s. In contrast, the 7.8 microM ATP-induced contractions increased by 50% within the first minute following incubation with 10 nM ET-1 but required about 5 min to develop the maximal effect. 4. The ET-1-induced potentiation of NANC or ATP responses was long-lasting and persisted in spite of extensive washing. The recovery of the bladder excitability depended on the concentration of ET-1. Following the application of 3 nM ET-1, recovery required 30 min; applications of 10 nM ET-1 required at least 60 min for full recovery. 5. The ET-1-induced potentiation of responses was selective for ATP and related structural analogues. ET-1 did not modify the contractions induced by acetylcholine, 5-hydroxytryptamine, prostaglandin F2 alpha or bradykinin. 6. The potency of ET-2 was similar to that of ET-1. ET-3 and ET-C-terminal hexapeptide were inactive up to 100 M. Sarafotoxin S6b was 2 to 3 fold less potent than ET-1 whereas sarafotoxin S6c (100 nM) was inactive. AGETB-9 and AGETB-89, two ETB receptor agonists, were also inactive (up to 100 nM). 7. Removal of one or both disulphide bonds in ET-1 and tryptophan-21 formylation of ET-1, resulted in inactive peptides (up to 100 nM). 8. The ET-1 receptor antagonists, BE-18257B and FR 139317, blocked both the ET-1-induced rise in tone and the potentiation of ATP responses in a concentration-dependent fashion. FR 139317 was at least 30 fold more potent than BE-18257B. Both antagonists blocked at lower concentrations the ET-1 increase in bladder tone as compared to the ATP potentiation. The antagonism was slowly reversible. 9. Results are consistent with the presence of ETA receptors in the rat bladder, which mediate both actions of ET-1. The interaction of ET-1 with purinergic mechanisms is discussed.

Adenosine Triphosphate↗
PubMed1994

[Reactivity of internal mammary artery and saphenous vein used in human myocardial revascularization: studies with endogenous vasoconstrictors and vasodilators].

Biopsies of human internal mammary artery and saphenous vein were examined to ascertain the functional integrity of these vessels employed in myocardial revascularization. Studies were performed in vascular rings derived from 28 patients without previous consideration of age, sex, underlying additional pathology or drug treatments previous to and during surgery. Isometric muscle contraction of the circular muscle layer was monitored. Endothelin-1 (ET) is equipotent as a vasoconstrictor in arteries and veins, with a potency at least 10 to 100-fold that of noradrenaline (NA) or serotonin (5-HT). The potency of ET, NA or 5-HT is unaltered by mechanical removal of the endothelial cell layer. Arterial rings precontracted with NA relaxed in a concentration-dependent fashion in the presence of acetylcholine and sodium nitroprusside. Whereas the potency of nitroprusside was unaltered by removal of the endothelium, the efficacy of acetylcholine was greatly reduced. Saphenous vein rings were refractory to acetylcholine but not nitroprusside. Results open new perspectives to explain the larger patency of internal mammary artery grafts as compared to that of saphenous vein grafts in human myocardial revascularization.

Endothelium, Vascular↗
PubMed1993

[Retrovesical hemangiopericytoma].

The hemangiopericytoma is an uncommon variety of the mesenchymal tumour derived from pericapillary structures, most frequently located in limbs and exceptionally at the retroperitoneum level. Although macroscopically the aspect is benign, this tumour has a recognised ability for local invasion and distant dissemination.

Abdominal Neoplasms↗
PubMed1992

Afferents to the oculomotor nucleus in the goldfish (Carassius auratus) as revealed by retrograde labeling with horseradish peroxidase.

The goal of this work was to compare the distribution and morphology of neurons projecting to the oculomotor nucleus in goldfish with those previously described in other vertebrate groups. Afferent neurons were revealed by retrograde labeling with horseradish peroxidase. The tracer was electrophoretically injected into the oculomotor nucleus. The location of the injection site was determined by the antidromic field potential elicited in the oculomotor nucleus by electrical stimulation of the oculomotor nerve. Labeled axons whose trajectories could be reconstructed were restricted to the medial longitudinal fasciculus. In order of quantitative importance, the afferent areas to the oculomotor nucleus were: (1) the ipsilateral anterior nucleus and the contralateral tangential and descending nuclei of the octaval column. Furthermore, a few labeled cells were found dorsomedially to the caudal pole of the unlabeled anterior octaval nucleus; (2) the contralateral abducens nucleus. The labeled internuclear neurons were arranged in two groups within and 500 microns behind the caudal subdivision of the abducens nucleus; (3) a few labeled cells were observed in the rhombencephalic reticular formation near the abducens nucleus, most of which were contralateral to the injection site. Specifically, stained cells were found in the caudal pole of the superior reticular nucleus, throughout the medial reticular nucleus and in the rostral area of the inferior reticular nucleus; (4) eurydendroid cells of the cerebellum, located close to the contralateral eminentia granularis pars lateralis, were also labeled; and (5) a small and primarily ipsilateral group of labeled cells was located at the mesencephalic nucleus of the medial longitudinal fasciculus. The similarity in the structures projecting to the oculomotor nucleus in goldfish to those in other vertebrates suggests that the neural network involved in the oculomotor system is quite conservative throughout phylogeny. Nevertheless, in goldfish these projections appeared with some specific peculiarities, such as the cerebellar and mesencephalic afferents to the oculomotor nucleus.

Afferent Pathways↗
PubMed1992

Effects of diazepam and D-amphetamine on rhythmic pattern of eye movements in goldfish.

The effects of diazepam and D-amphetamine on spontaneous, vestibular- and visually-induced eye movements were studied in the restrained goldfish. These animals showed a stereotyped pattern of spontaneous eye movements that scanned the visual field in the horizontal plane. Fourier analysis of these eye movements revealed a rhythmic pattern of about 5 cycles per minute, whose frequency increased to double and decreased to half following treatment with diazepam and D-amphetamine, respectively. However, the fast and slow components of vestibulo-ocular and optokinetic reflexes, as well as peculiar blink-like movements, remained unchanged at the same drug doses. These results suggest the presence of a central pattern generator for spontaneous eye movements in the goldfish, whose oscillation frequency is pharmacologically modifiable.

Animals↗
PubMed1992

Further appraisal of APACHE II limitations and potential.

Hemodynamically unstable patients selected for invasive cardiovascular monitoring were divided into APACHE II subgroups for risk stratification to study interrelationships among monitoring, therapy, resulting cardiovascular function and outcome. When compared by regression analysis, there were no clinically relevant relationships between APACHE II scores and total intervention points (r2 = 0.02), days of invasive monitoring (r2 = 0.000001), initial cardiovascular function (r2 = 0.069) and final cardiovascular function (r2 = 0.05). Analysis of variance (ANOVA) was done between APACHE subgroups and total points (zero of 20 intragroup comparisons were different by the Scheffé test; p = 0.33), days of monitoring (zero of 20 were different; p = 0.61), initial cardiovascular function (three of 20 comparisons were different; p = 0.003) and final cardiovascular function (zero of 20 were different; p = 0.24). Opposite relationships in patients who lived and died were noted between total intervention points and APACHE II subgroups (p = 0.028, two-way ANOVA). There was an increasing number of total intervention points in patients who ultimately lived in ascending initial APACHE II subgroups. In contrast, there was a decreasing number of total intervention points in patients who ultimately died in the same APACHE II subgroups. APACHE II stratification failed to help understand the relationships among clinically important parameters. At the same time, while APACHE scores are claimed to be independent of therapy, the score seemed to be extremely sensitive to interventions, especially important in surgical populations. Should the APACHE II scores remain high in the face of continued maximal intervention, fatal outcome can be predicted. This pattern is remarkably similar across the entire initial APACHE spectrum. The predicated attributes of APACHE II scores, that is, risk stratification and independence from therapy, are neither necessary or desirable. Understanding patterns that are associated with survival or death may require alternative mathematic approaches, such as group and set theory manipulated by principles of Boolean algebra. New approaches may be more fruitful than further attempts to refine existing systems.

Analysis of Variance↗
PubMed1992

[Metastasis of prostatic origin in periorbital soft tissues].

Appearance of orbital metastatic (OM) neoplasia is the most frequent cause of eye tumour; however, its incidence related to prostatic carcinoma (PC) is rare, primarily when there is sole infiltration of the periorbital soft tissue (STOM). The paper describes the case of a patient diagnosed with PC presenting proptosis and diplodia as first spread symptoms. The rarity of STOM of the prostatic carcinoma prompted the diagnosis to be seen sceptically until immunohistochemical confirmation was obtained. An analysis is made of various features of interest regarding the grading of OM, clinical incidence and diagnostic methods. The singularity of the present case, affecting only the periocular soft tissues is illustrated. Finally, the situations requiring orbital biopsy in order to avoid a second neoplasia are analyzed.

Carcinoma↗
PubMed1988

Offense and defense after lateral septal lesions in Columba livia.

It is generally agreed that there are several different types of animal aggression that may be distinguished in terms of their neural organization and that discrete lesions, in particular brain areas, may affect one but not other types of aggression. In this study the effects of electrolytic, bilateral lesions in lateral septum on offense and defense were examined in pigeons. Subjects were tested by introducing an adult conspecific stranger into their home cage. A postoperative increase in offensive patterns and a long-lasting drop in defense were observed in the lesioned birds. Its remarkable resemblance to the effects of antianxiety drugs, as well as the difference between the behavioral effects of medial septal damage are also discussed.

Aggression↗
PubMed1987

Bilateral abscessed orchiepididymitis associated with sepsis caused by Veillonella parvula and Clostridium perfringens: case report and review of the literature.

Veillonella species is a gram-negative coccus which is part of the anaerobic normal flora in the oral cavity, small intestine, upper respiratory tract, vagina, and urinary tract. The role that this organism plays in infection is not well known, and it is generally associated with other bacteria. We present a case of bilateral abscessed orchiepididymitis associated with septicemia due to Veillonella parvula and, later, to Clostridium perfringens, with the development of severe renal insufficiency and septic shock, which resolved favorably with antibiotic therapy, treatment of shock, and hyperbaric oxygen therapy. In reviewing the literature, we have not found any other case of sepsis due to Veillonella sp. associated with urological disorders.

Abscess↗
PubMed1981

Mechanism of inhibition of enzymatic deoxyribonucleic acid methylation by 2-(acetylamino)fluorene bound to deoxyribonucleic acid.

Binding of 2-(acetylamino)fluorene (AAF) to C-8 of guanine induces a local destabilization of the DNA helix. A relationship was observed where the degree of DNA modification by AAF was inversely proportional to its methyl acceptor capacity from S-adenosyl-L-methionine in the presence of rat brain DNA cytosine 5-methyltransferase. Moreover, substituted DNA (DNA-AAF) behaves as a methylation inhibitor of native DNA. This inhibition is of the mixed type. The substituted DNAs have higher affinities for the enzyme than native DNA. The inhibition is irreversible. Addition of DNA-AAF to the enzyme preincubated with native DNA inhibits methylation, but only after a lag period. This agrees with the model in which the methylase "walks" along the strand to methylate cytosine residues before being detached from the DNA. AAF bound to guanine residues may block the movement of the enzyme along the helix. Single-stranded DNA has an affinity for the methylase 1.6 times lower than that of native double-stranded DNA. On the other hand, single-stranded DNA-AAF is more methylated than double-stranded DNA-AAF. A tentative model taking into account these observations is presented under Discussion. The in vitro hypomethylation of DNA-AAF could explain the in vivo observations made by several authors.

2-Acetylaminofluorene↗