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C Peña

Publications and source records attributed to C Peña.

139 records · Page 8Linked to original sources
PubMedDate not supplied

Characterization of synaptosomal membrane Na+, K(+)-ATPase inhibitors.

Previous work carried out in this laboratory has led to the isolation from rat brain of an aqueous soluble fraction (peak II) inhibiting synaptosomal membrane Na+, K(+)-ATPase and possessing other ouabain-like properties. Brain peak II was subjected to several treatments or fractionation by reversed-phase or anionic exchange HPLC and the effect of resultant fractions tested on synaptosomal membrane ATPase activity. The inhibitory components proved highly hydrophilic since they were neither extracted by hexane nor retained by a C-18 HPLC column, ruling out a lipidic nature. By anionic exchange chromatography, peak II was separated into eight fractions, two of which, named II-A and II-E, presented inhibitory activity, had low molecular weight, reacted with ninhydrin and were sensitive to acid hydrolysis. Fraction II-A was further chromatographed through a C-18 column, rendering five fractions, II-A1 to II-A5, inhibitory activity being confined to the most hydrophilic one (II-A1). Fraction II-E seems non-peptidic in nature, and its inhibitory activity was completed lost by alkalinization. II-E differs from authentic ouabain in u.v. spectrum, chromatographic behaviour and alkali sensitivity. It is suggested that two small hydrophilic compounds, probably one peptidic (II-A1) and another non-peptidic (II-E) in nature are involved in the regulation of Na+, K(+)-ATPase activity at the synaptic membranes.

4-Nitrophenylphosphatase↗
PubMedDate not supplied

Effect of oscillating dissolved oxygen tension on the production of alginate by Azotobacter vinelandii.

The effect of oscillating dissolved oxygen tension (DOT) on the metabolism of an exopolysaccharide-producing bacteria (Azotobacter vinelandii) was investigated, particularly on the mean molecular weight (MMW) of the alginate produced. Sinusoidal DOT oscillations were attained by manipulating the oxygen and nitrogen partial pressures at the inlet of a 1.0 L working volume bioreactor. Periods of 1200, 2400, and 4000 s and average amplitudes between 1.0% and 2.2% DOT, with an oscillation axis fixed at 3% DOT, were tested. A culture carried out at constant 3% DOT was used as comparison. The average wave amplitude had an important effect on the maximum mean molecular weight (MMW(max)) of the alginate produced. The higher the amplitude, the lower the MMW(max). As the average wave amplitudes decreased from 2.2% to 1.0%, the MMW(max) increased from 64 to 240 KDa, respectively. Furthermore, at 3% constant DOT (0.0% of amplitude), a MMW(max) of 350 KDa was obtained. No important effect of the oscillating DOT on kinetics of biomass growth, alginate production, and sucrose consumption was observed, compared with constant DOT. The findings of this study point out that accurate DOT control is crucial if a particular molecular weight species of alginate needs to be produced, particularly in large fermentors, where bacteria are exposed to an oscillatory environment as a result of DOT gradients caused by the high viscosity of the broth and insufficient mixing.

Alginates↗
PubMedDate not supplied

[Atypical cutaneous sporotrichosis. The response to itraconazole and surgery].

Sporotrichosis is a subcutaneous (rarely extracutaneous) fungal disease caused by Sporothrix schenckii. Cutaneous sporotrichosis has two well-defined forms: lymphocutaneous and stable. In lymphocutaneous sporotrichosis, lesions arise along lymphatic vessels, generally in limbs. The stable form is rarer and consists of a single, generally facial, lesion. We report the case of a 70-year-old male farmer with a single lesion on the right nostril that had been removed repeatedly. After 5 years, new, linearly distributed lesions appeared. Fungal cultures of biopsy tissues revealed S. schenckii. The evolution and response to treatment with itraconazole, potassium iodide, terbinafine, and surgery is discussed.

Aged↗
PubMedDate not supplied

Monitoring the purity of a synthetic peptide by capillary electrophoresis: utilization of an on-line preconcentration method for improved separation and detection sensitivity.

To date, there has been a considerable amount of interest and success in the pharmaceutical industry in the discovery of drug targets and diagnostics utilizing peptides. The success of peptide pharmaceuticals has, however, been accompanied by some failures, both prior to entry and in the clinic. Progress has been made in various areas to improve the effectiveness of the final drug product. One major advance has been in the area of peptide synthesis and control of the purity of the peptide of interest. Recent advances in analytical instrumentation, including advances in capillary electrophoresis, have had a great impact on the ability to separate and detect low quantities of impurities and degradation products during the synthesis of a peptide drug. In this work, affinity capillary electrophoresis (ACE) was developed for the identification and characterization of a chemically synthesized peptide fragment of a snake toxin called fasciculin. The affinity capillary electrophoresis technology utilized in this study employed two powerful techniques coupled on-line for the direct and rapid determination of analytes in simple and complex matrices. The first technique, aimed for the nonselective extraction and concentration of one or more analytes of interest, utilizes a solid-phase analyte concentrator device. The second technique, capillary electrophoresis, is used for the high-resolution analytical separation of the purified and concentrated target analyte(s), after elution from an analyte concentrator device. The on-line preconcentration step has proved valuable in terms of improving separation conditions as well as enhancing detection sensitivity values for the peptide fragment with a sensitivity increase ranging from 100- to 10,000-fold. Different types of analyte concentrator devices and a few binding-desorption conditions were tested. Bare and internal-wall-coated fused-silica capillaries were used. Comparative performance with HPLC in terms of selectivity and sensitivity is also discussed.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

[Depressive states in multiple sclerosis. Critical bibliographic review].

The aim of this paper is to review the question of depression in patients with multiple sclerosis (MS). Morbidity and methodological difficulties in the investigation of depressive states in MS are analyzed. Prevalence of depression in MS in previous series is critically compared. The role of chronic invalidity and topography of demyelinating lesions in the development of depression are considered. We also review the treatment of depressive states and future guidelines for investigation of this topic.

Brain↗
PubMedDate not supplied

[The "Sickness Impact Profile" questionnaire (SIP): Spanish version of a measure of health status].

The objective of this paper is to present the results of the translation and adaptation into Spanish of a questionnaire (The Sickness Impact Profile --SIP--) for measuring the physical and psychosocial dysfunctions generated by a disease. For this the SIP, together with some clinical measures of physical and psychosocial status were administered to a series of 50 patients afflicted by multiple sclerosis. We found not only that the SIP could be considered a good instrument for measuring the physical and psychosocial impact of illness, but also that it is adequate to differentiate in it a physical and a psychosocial dimensions.

Humans↗
PubMedDate not supplied

[Risk profiles for mental disorders in the general population].

This study examined, in the general population, the effect which different sociodemographic variables and the presence of physical illness esserted on the probability of suffering from mental disorders. For this we applied, among other instruments, the GHQ-60 to a random sample of 1.223 persons from a community of Cantabria. The estimated probable prevalence of mental disorders detected with the GHQ-60 was 14.7% (6.5% for males and 19.6% for females). the analysis, by means of logistic modelling, of the influence which 6 sociodemographic variables and physical illness exerted on the probability of suffering from psychiatric illness revelled that is possible to establish for each sex a specific profile of risk of suffering from psychiatric disorders. Two factors, physical illness, in both sexes, and absence of work, exclusively on males, appears to have a significant influence on the probability of suffering from minor psychiatric disorders.

Adolescent↗
PubMedDate not supplied

[Clinical aspects of ventricular fibrillation in the development of myocardial infarction].

We report 13 patients who suffered ventricular fibrillation (VF) during the in-hospital course of an acute myocardial infarction (AMI). We compare the clinical features of this patients with other two groups; patients without VF and patients with intraventricular conduction defects. In 38% of the cases VF appeared after 5th day of the AMI. The group of patients with VF was characterized by an increased incidence of heart failure, supra-ventricular and ventricular premature beats, and also intra-ventricular conduction defects. In 2 patients VF appeared during the course of treatment with therapeutic doses of lidocaine. Sixty two percent of the patients with VF were discharged alive. We recommend that patients with AMI who display the above mentioned risk factor, should remain in the coronary care unit for a more prolonged period of time. By proceeding in this way, we had the opportunity to observe and immediately treat 5 further patients with AMI and VF. All of them recovered.

Aged↗
PubMedDate not supplied

Clinical study of comparative plaque removal performance of two manual toothbrushes.

A clinical study was performed to evaluate and compare plaque removal performance of the two commercially available products; the Colgate Precision Full Head Soft toothbrush and Reach Full Head soft toothbrush. Twenty high school students, male and female subjects participated, each refraining from toothbrushing for 24 hours. Plaque was scored according to the Personal Hygiene Performance (PHP) Index of Podshadley and Haley, as modified by Martens and Meskin. Following screening, the subjects were divided into two balanced groups on the basis of initial plaque scores. At Visit 1, each group having refrained from toothbrushing for 24 hours, was evaluated for plaque before brushing for 60 seconds with the assigned toothbrush, after which plaque was again scored. At Visit 2, one week later, the same procedure was followed. Subjects were instructed to resume their normal routine and return to the clinical site for Visit 2. On completion of the study, the data collected were subjected to statistical analysis which indicated that the Colgate Precision Full Head soft toothbrush removed significantly more plaque than Reach Full Head soft toothbrush.

Adolescent↗