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Biomedical subjects

J C García

Publications and source records attributed to J C García.

36 records · Page 2Linked to original sources

[Function of growth hormone in the human energy continuum during physical exertion].

A study has been carried out in 18 healthy sedentary males (controls) and 15 trained handball players. It was programmed two different tests on cycle-ergometer: Test 1 aerobic of progressive increments of load (1 W/kg/3 min) and Test 2 (A) anaerobic (4 W/kg, during 1.5 min) and after resting 10 min., Test 2 (B) till exhaustion. The blood samples were 10 ml each collected by antecubital vein catheterization. Before, during and post-exercise recovery period HG hormone, glycemia, lactate, and FFA were measured. It was found a correlation between HGH levels and substances of the energetic metabolism. The only exception was trained subjects test-2 possibly due to slower response of HGH. However FFA variation levels are correlated at the beginning with the increasing levels (p less than 0.001). It is concluded that HGH can play an important role on the turn-over to get fuel to contractile process from carbohydrates to free fatty acids.

Adult↗

Effect of ethanol on the specific transport system for L-lysine in Saccharomyces cerevisiae.

Preincubation of resting cells of Saccharomyces cerevisiae double mutant can1 gap1 (with a single transport system for L-lysine) with metabolic substrates stimulated subsequent uptake of lysine. While in the wild type the stimulation is connected primarily with carrier protein synthesis (delayed, cycloheximide-inhibitable effect) in the mutant an immediate tapping of an energy source (antimycin-inhibited) is practically solely involved.

Amino Acids↗

Uptake of L-lysine by a double mutant of Saccharomyces cerevisiae.

A gap1 can1 mutant of Saccharomyces cerevisiae with a single lysine transport system remaining was used to study detailed kinetics of this transport. Its half-saturation constant was 78 mumol per litre, its maximum rate of transport was 0.29 mumol L-lysine per g dry matter per minute, both parameters being lower by more than an order of magnitude in comparison with the GAP system. The pH optimum lay at very acid values of about 3, the temperature dependence without any transition point showed an activation energy of 48 kJ/mol. The transport was inhibited by common metabolic inhibitors (3'-chlorophenylhydrazonomalononitrile, antimycin, 2-deoxy-D-glucose, sodium arsenate) as well as by a membrane-active one (uranyl nitrate). The specificity of the system was extremely high, none of the natural amino acids acting as competitor to L-lysine. The maximum accumulation ratio attained (at about 5 mg dry matter per mL) was 100: 1-120: 1, in agreement with the measured protonmotive force under the assumption of 1 H+ ion being transported with 1 lysine molecule. The ratio decreased with increasing external concentration of lysine to as little as 4: 1 at 1 mmol lysine per litre. It also decreased with increasing suspension density and it was at extremely low suspension densities (0.2 mg dry matter per mL) that ratios of as much as 500: 1 were reached. Application of group-specific inhibitors showed that the active site of the carrier contains an essential histidine residue.

Glucose↗

The use of isosorbide in the treatment of severe, uncontrolled hypertension.

Isosorbide dinitrate was administered sublingually and compared with placebo in a double-blind, randomized fashion to determine its effectiveness and safety in the rapid control of severe arterial hypertension. In 11 patients who received 10 mg of isosorbide dinitrate, blood pressure (BP) dropped from 205 +/- 8/131 +/- 3 to 166 +/- 9/106 +/- 5 mm Hg at 120 minutes. In eight patients who received placebo, BP dropped from 203 +/- 8/130 +/- 3 to 193 +/- 11/122 +/- 5 mm Hg at 120 minutes. When 10 mg of isosorbide dinitrate was administered sublingually after 120 minutes to placebo-pretreated patients, their BP dropped to 161 +/- 7/105 +/- 6 mm Hg at 240 minutes. Our study group (19 patients) was compared with a "control" group (six patients) whose BP (203 +/- 12/132 +/- 8 mm Hg) was treated only with conventional antihypertensive medications and bed rest; five (83%) of the six controls achieved steady BP control at 24 hours vs nine (47%) of the 19 study patients pretreated with isosorbide. There were no side effects, including hypotension, orthostatic effect, and reflex tachycardia. Sublingual isosorbide safely and effectively lowers systolic and diastolic BP in patients with severe, uncontrolled arterial hypertension.

Administration, Oral↗

[Medicine and society. Schools of thought in the health field].

The article considers the answers given by different schools of thought to the fundamental questions about the degree of autonomy of medicine and the kind of articulation between medicine and society as a whole and in its "parts." The answers vary with the thinking in the different social sciences and the philosophic schools associated with them. The author divides his presentation in two broad chapters: The first covers schools of thought in the health field, and attempts to delineate the philosophical foundations underlying the principal current schools of thought in this field, without attempting a history of the philosophical schools or analyzing each of them in detail. Thus, two idealist currents are studied which have exerted great influence in the health field--neopositivism and neo-Kantianism--and marxism as the materialist school, which recognizes the primary of matter, nature, and objective reality, and views consciousness as a property of matter. The second chapter considers the theoretical contest now going on among the schools of thought discussed in the first chapter, which try to explain the relationship between medicine and the social structure; the effectiveness of medical action, and the social determinants of disease. Prior to the seventies, the author says, the dominant view of the autonomy of medicine, its effectiveness, the potential for social change of the medical institutions, and the benefits to health of economic development, was endorsed by the predominance of positivism among these schools of medical thought. The view that medicine was broadly autonomous and at the same level with other subsystems such as the economic, the political and the educational subsystems, assumed the possibility of changing society by an effort begun through any of these "sectors." The enormous growth of productive forces that took place in the developed capitalist countries during the fifties, and even more during the sixties, collided at the end of the latter decade with the existing social production relations, which checked the progress of the production forces and generated a series of challenges in civil society to the aims of economic development and the achievements of science in relation to the inequality of the distribution of wealth. In the health sector, this was a time of criticism of the positivist view and of pointing out the negative effects of medicalization, highlighting the ideological and self-perpetuating character of medical institutions, and proposals for the demedicalization of society.(ABSTRACT TRUNCATED AT 400 WORDS)

History, 19th Century↗

Effect of sodium orthovanadate on renal renin secretion in vivo.

The effect of vanadate (0.5 mumol/min) on renin secretory rate (RSR) of the kidney has been studied in nembutal-anesthetized, volume-expanded dogs. Intrarenal vanadate infusion caused a 69.3 +/- 8.8% decrease in RSR. This was accompanied by marked decreases in renal blood flow (RBF), glomerular filtration rate (GFR) and fractional excretion of sodium (FENa). Renal vascular resistance rose from 1.3 +/- 0.09 to 6.1 +/- 2.3 mm Hg/ml/min (P less than .0005). Papaverine infusion partially blunted the effect of vanadate on RSR (RSR only fell to 42. +/- 10% of basal values). The decreases in RBF and GFR were also less and FENa slightly higher than normal. Acetylcholine prevented the effects of vanadate more fully. There was no fall in RBF, GFR or FENa and it basically abolished the fall in RSR which fell only 19.4 +/- 25.3 of control (P = N.S.). Nifedipine (a slow Ca++ channels blocker) also prevented the fall in RBF, GFR and FENa induced by vanadate. RSR did not change significantly (7.8 +/- 10.9%). These results clearly demonstrate that vanadate is a potent inhibitor of renin secretion and suggest that inhibition of smooth muscle Na+, K+, adenasine triphosphatase and changes in the cystosolic concentration of Na and Ca are involved in its mechanism. Changes in perfusion pressure and sodium delivery to the macula densa appear to have little if any role in the inhibition.

Acetylcholine↗

Squamous cell carcinoma of the oropharynx and esophagus in a Japanese bantam rooster.

Squamous cell carcinoma of the oropharynx and esophagus was diagnosed in an adult Japanese bantam rooster. Grossly, a cauliflowerlike mass with irregular edges was found involving the ventrolateral surfaces of the caudal portion of the oropharynx and cervical portion of the esophagus. The large volume of the mass almost occluded the lumen of the alimentary passage. Histologically, the tumor consisted of irregular cords of pleomorphic epithelial cells that showed a disorganized pattern of growth and invaded the adjacent tissues. Keratinized epithelial cells and moderate numbers of keratin pearls were readily observed. The mitotic index was low, and, although the tumor was locally invasive, we found no evidence of vascular invasion or metastasis.

Animals↗

Monoamine metabolites in normal human cerebrospinal fluid and in degenerative diseases of the central nervous system.

Measurement of monoamine metabolites in cerebrospinal fluid (CSF) has been one of the few methods available to study monoamine transmitter function in the human central nervous system (CNS). It has steadily proved to be of much use in clinical research of neurological and psychiatric diseases, in which altered functions of central monoamine neurotransmitters have been identified. In this work 3-methoxy-4-hydroxyphenylethylglycol (MHPG), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were quantified in normal CSF and in patients with untreated Parkinson's disease (PD) and olivopontocerebellar atrophy (OPCA). Normal CSF was obtained from 162 patients at the time of spinal anesthesia for surgery. Reference values for monoamine metabolites were established for normal adult lumbar CSF. Up to the age of 70 years no relation of monoamine metabolite concentration with age or sex were encountered. In individuals above 70 years of age higher levels of MHPG, HVA, and 5-HIAA were present in women, while in men only higher levels of MHPG could be detected. A strong correlation between 5-HIAA and HVA concentrations were observed in all groups. PD patients exhibited normal CSF metabolite levels, but an altered 5-HIAA/HVA ratio, favoring 5-HIAA. Dominant and recessive OPCA differed essentially in HVA concentration-diminished in the first group and elevated in the last. Comparing the results obtained in PD and dominant OPCA, we suggest that the decrease of CSF HVA in the latter group might not reflect nigrostriatal degeneration as we previously thought. Possibly another factor influencing dopamine function in the CNS is involved.

3,4-Dihydroxyphenylacetic Acid↗

IgE binding proteins in honey: discussion on their origin.

Pollen proteins, most frequently from Compositae plants, and glandular enzymes from Hymenoptera insects are the only honey allergens involved in every case of honey sensitization reported so far. Surprisingly, we found three patients, all showing the same pattern of honey sensitization with clinical history, cutaneous test and specific IgE clearly positive to honey crude extract but not to the aforementioned components. IgE binding bands, mainly at 54, 46, 17 and 16 kDa, were recognized by the sera of the three patients on blots following electrophoretic separation of a local honey extract under dissociating conditions. Attempts to identify these proteins with the most common honey allergens by means of SDS-PAGE immunoblotting failed, leaving open the question on the origin of protein allergens in cases of honey allergy. Thus, if bee-derived components are not proven to be involved in honey sensitization, other protein sources, such as nectar, should not be disregarded.

Adult↗

Fixed drug eruption induced by lidocaine and patch testing.

Fixed drug eruption (FDE) is a peculiar drug-induced cutaneous reaction, that characteristically reappears at the same site when the etiologic drug is readministered. We present a case of a 27-year old male who was referred to us after two episodes of erythema on the palms, soles, and genital areas with posterior desquamation after receiving local anesthetics. Skin tests with lidocaine, mepivacaine and bupivacaine were negative. Eight hours after challenge with lidocaine the lesions reoccurred. Patch tests with lidocaine on healthy skin and residual lesions were negative, but 48 hours later the lesions reappeared on the same areas as before. Challenge with mepivacaine and bupivacaine were negative.

Adult↗