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Biomedical subjects

J Frías

Publications and source records attributed to J Frías.

31 records · Page 2Linked to original sources
PubMed1995

Assessment of biological activity and fate of organic compounds in a reactor for the measurement of biodegradable organic carbon in water.

A new, rapid method for the determination of biodegradable dissolved organic carbon (BDOC), especially suited to water industry needs, was recently proposed by the authors. This dynamic method measured the BDOC of circulating water continuously pumped over a biofilm attached to a special support (sinterized porous glass) that fills a system of two glass columns. The BDOC value corresponds to the difference in dissolved organic carbon (DOC) between inflow and outflow water samples. The analytical results are not significantly different from those of other bioassays that use indigenous bacteria, and the total duration of the analysis is less than 3 h. However, a problem common to all the BDOC methods based on attached bacteria is the extent to which the decrease in DOC during the BDOC analysis is due to true biodegradation or to adsorption of organic matter to the reactor. In the present study, a reasonable support is provided for the hypothesis that this decrease, at least in the dynamic method, is predominantly due to microbiological activity. After comparing the support (sinterized porous glass) with a good physical adsorbent (granular activated carbon), the influence of temperature, residual chlorine and sodium azide on the reactor performance was tested, and a sensitivity only attributable to biological activity was observed. Another set of experiments were performed to assess the fate and specific elimination of different organic substances, explicable assuming that biodegradation processes were involved.

Azides↗
PubMed1993

Changes in the carbohydrate composition of legumes after soaking and cooking.

Using a high-performance liquid chromatography (HPLC) method, researchers analyzed the sugar composition of chick-peas, kidney beans, and lentils at various points in the preparation and cooking process: after soaking, after "normal" cooking (ie, boiling), after pressure-cooking, and after cooked legumes had been held at 35 degrees C for 5 hours. There was a considerable decrease in the amount of monosaccharides, disaccharides, and raffinose oligosaccharides in chick-peas and kidney beans after soaking and cooking. This change in carbohydrate composition was less pronounced when the cooking water was not drained before analysis, which was the method used when analyzing the lentils. Method of cooking (either boiling or pressure-cooking) did not have different effects on the sugar composition of chick-peas and lentils, but loss of oligosaccharides was slightly higher when kidney beans were boiled than when they were pressure-cooked. Loss of alpha-galactosides occurred in chick-peas and kidney beans that had been boiled and then held at 35 degrees C for 5 hours. The HPLC analysis showed that manninotriose was not one of the oligosaccharides present in these legumes.

Carbohydrates↗
PubMed1991

[Hospitalizations because of drugs: a prospective study].

A study was carried out during five months in La Paz Hospital with the objective to know the proportion of admissions due to an adverse reaction to pharmaceutical drugs (RAM) or due to an acute drug intoxication. For this purpose the reports of all patients seen at the Medical Emergency Room were analyzed on a daily basis. Out of 1,847 patients who needed hospital admission during this time period, 88 (4.8%) were considered to need so due to RAM or an acute intoxication. Out of 145 acute intoxications treated, 16 patients (0.9% of total admissions) had to be hospitalized. RAM constituted 3.9% of admissions, with upper GI tract hemorrhages the most frequent cause (62.5%; 72 cases). The groups of drugs responsible in most RAM were the analgesics and NSAIDs, in particular acetylsalicylic acid, followed by hypoglycemic drugs and digoxin.

Acute Disease↗
PubMed1989

[Adverse reactions to drugs as a reason for consulting the emergency service of a general hospital].

The reports from the emergency service of La Paz General Hospital were daily reviewed for 4 months to investigate the number of consultations which, on the judgement of the physician on care, were due to adverse reactions to drugs. An overall number of 11,326 patients consulted. In 438 (3.9%) it was considered that the consultation was due to one or more definite, likely or possible adverse drug reactions. In 69 patients (15.8%), the reactions were considered to be severe, and 54 (12.3%) required admission; 59 reactions (13.4%) were moderate, and 310 (70.8%) were mild. The most common localizations were the skin and its appendages (37.7%) and gastrointestinal tract (25.3%). The most commonly implicated pharmacologic groups were analgesic and non-steroidal anti-inflammatory drugs (33.6%) and antimicrobials (22.1%). The incidence of adverse reactions was significantly higher in women (4.4% vs 3.3% in males, p less than 0.01). Depending on the age groups (14-29, 30-59, greater than or equal to 60 years) the incidence of nonallergic adverse reactions was significantly higher in patients aged 60 years or more (1.5%, 2%, 2.9%; chi 2 = 15.2, gl = 2, p less than 0.001). In presumably allergic adverse reactions, the incidence was significantly higher among those under 30 years (2.9%, 2.2%, 0.5%; chi 2 = 50.2; gl = 2, p less than 0.0001). The incidence of severe adverse reactions was significantly higher in patients over age 60 years (0.2%, 0.6%, 1.2%, chi 2 = 29.2, gl = 2, p less than 0.001). In 32% of cases the adverse reactions might have been prevented.

Adolescent↗
PubMed1988

"Doctor" in Spain.

Explore the source record for details and available documents.

Education, Medical↗
PubMedDate not supplied

Dihydropyridine BAY-K-8644 activates chromaffin cell calcium channels.

Douglas and Rubin suggested that "the role of acetylcholine as a transmitter at the adrenal medulla is to cause some brief change in medullary cells which allows Ca ions to penetrate them and trigger the catecholamine ejection process". The Ca2+-channel blocking agents, verapamil, nifedipine and nitrendipine, have been used widely to investigate the properties of slow Ca2+ channels in a variety of tissues, including the adrenomedullary chromaffin cell. Recently, small modifications to the nifedipine molecule produced a derivative, BAY-K-8644 (methyl-1,4-dihydro-2, 6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyridine-5-carboxylate), that in contrast to the Ca2+-channel blocking agents, stimulated cardiac and vascular smooth muscle contractility. We have tested whether this compound behaves as a Ca2+-channel activator at the chromaffin cell membrane as shown by Schramm et al. in smooth muscle cells. The experiments described here strongly suggest that it does so.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMedDate not supplied

X-ray studies on phospholipid bilayers. XIII. Interactions with gentamicin.

This study deals with the structural perturbations that the aminoglycoside antibiotic gentamicin (GENT) can produce to phospholipid bilayers. Two multi-bilayer systems, one built-up of dimyristoylphosphatidylcholine (DMPC) and the other of dimyristoylphosphatidylethanolamine (DMPE) were allowed to interact with GENT. The experiments were performed in both a hydrophobic and a hydrophilic medium below the phospholipid main transition temperatures. X-ray diffraction techniques were used to determine the extent of the perturbation induced by GENT. The maximum effect was attained when GENT interacted with DMPC in the hydrophobic medium. On the other hand, GENT in aqueous solutions was unable to perturb in any significant extent the structure of the phospholipids under study.

Carbohydrate Conformation↗