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Biomedical subjects

P Gonzalez

Publications and source records attributed to P Gonzalez.

At least 73 records · Page 4Linked to original sources
PubMed1994

Incidence of cervical spine injury in patients with gunshot wounds to the head.

Cervical spine immobilization is standard during the early stages of prehospital and hospital care of patients with blunt head injury. However, the need for cervical spine immobilization in patients with gunshot wounds to the head has not been addressed. To determine the incidence and types of cervical spine injury in this group, we retrospectively examined the records of 308 consecutive patients who had computed tomographic (CT) scans of the head to evaluate brain injury after gunshot wounds. Of the 266 patients with data adequate for review, 157 (59%) had a complete lateral x-ray film of the cervical spine. Of these 157, 105 had wounds limited to the calvaria, and none had cervical spine injury. Of 52 patients with complete lateral x-ray films and wounds not limited to the calvaria, 5 (10%) had cervical spine or spinal cord injury. Of the 192 patients who had CT-proven intracranial injury, 86 (45%) required immediate intubation before x-ray films were obtained, and 67 (35%) died. We conclude that cervical spine immobilization may not be required during endotracheal intubation of brain-injured gunshot victims with wounds limited to the calvaria.

Brain Injuries↗
PubMed1994

Preliminary study of treatment of sulphuric pickling water waste from steelmaking by bio-oxidation with Thiobacillus ferrooxidans.

This report looks at the laboratory-scale recovery of iron oxides (alpha Fe2O3 type) through bio-oxidation with Thiobacillus ferrooxidans of the ferrous sulphate contained in steel industry sulphuric pickling liquors. This is done by calcining iron sulphates and iron and ammonium sulphates obtained from the crystallization of the oxidized solution. The products of the bacterial reaction and the iron oxides are then studied according to calcination temperature. The process carried out produced 50 kg of alpha Fe2O3 per m3 of waste pickling liquor at 700 degrees C with 99.8% weight iron recovery.

Ferrous Compounds↗
PubMed1993

Effects of indapamide on contractile responses and 45Ca2+ movements in various isolated blood vessels.

The effects of indapamide on contractile responses in various isolated artery rings and on spontaneous mechanical activity in portal vein segments were investigated. Arteries used were: rabbit aorta, mesenteric (fifth branch), femoral and basilar, and sheep coronary arteries. 45Ca2+ uptake was also analysed in rabbit mesenteric arteries. Indapamide (10(-10)-3 x 10(-4) M) produced a concentration-dependent inhibition of the contractile responses induced by high K+ (80 mM), 5-hydroxytryptamine (10(-5) M), and noradrenaline (10(-6) or 10(-4) M) in all the arteries studied. The inhibitory effect was greater in mesenteric (fifth branch) the IC50 values being 9.2 +/- 3.0 x 10(-6) and 5.5 +/- 4.0 x 10(-8) M for depression of high K(+)- and agonist-induced contractions, respectively. Indapamide inhibited in a concentration-dependent manner the contractile responses elicited by the addition of Ca2+ (1-5 mM) to Ca(2+)-free high K+ solution as well as the spontaneous mechanical activity of rat portal vein. Indapamide also reduced the 45Ca2+ uptake in rabbit mesenteric arteries stimulated by noradrenaline (10(-4) M) or by high K+ (80 mM) without affecting the Ca2+ influx in resting tissues. Our results indicate that indapamide blocked both depolarization-and noradrenaline-induced Ca2+ influx while it did not modify passive Ca2+ entry. Peripheral resistance vessels were demonstrated to be the arteries most sensitive to indapamide vascular effects.

Animals↗
PubMed1993

Effects of dotarizine on 45Ca2+ movements and contractile responses in vascular smooth muscle.

The inhibitory effects of dotarizine on 45Ca2+ movements and contractile responses were studied and compared, using the same parameters measured in rabbit aorta and basilar smooth muscle. Dotarizine 10(-9)-10(-5) M inhibited the contractile responses induced by high K+ (80 mM), noradrenaline (10(-6) M) or 5-hydroxytryptamine (5-HT, 10(-5) M). These effects were observed when dotarizine was added before or after the induced contractions and were more potent in basilar arteries than in aorta. Moreover, dotarizine at concentrations less than 10(-6) M did not modify the contractile response obtained in aorta rings. Contractile responses induced by the addition of Ca2+ to Ca(2+)-free high-K+ solution were also concentration dependently inhibited by dotarizine 10(-7)-10(-6) M in aorta and basilar arteries. Dotarizine also inhibited the contractile response induced by caffeine (20 mM) in aortic rings incubated in normal or in Ca(2+)-free medium. Dotarizine reduced the 45Ca(2+) uptake stimulated by high K+, noradrenaline or 5-HT even in the aorta or basilar artery, but the inhibition was greater in basilar arteries than in aorta. These results suggest that, in rabbit, dotarizine inhibits Ca2+ entry through Ca2+ channels, being more selective for the basilar artery, probably by acting on multiple sites to decrease the availability of intracellular free Ca2+ required for activation.

Animals↗
PubMed1993

Zeta-crystallin versus other members of the alcohol dehydrogenase super-family. Variability as a functional characteristic.

Species variability of the lens protein zeta-crystallin was correlated with those of alcohol dehydrogenases of classes I and III and sorbitol dehydrogenase in the same protein family. The extent of overall variability, nature of residues conserved, and patterns of segment variability, all fall within the limits typical of the 'variable' group of medium-chain alcohol dehydrogenases. This shows that zeta-crystallin is subject to restrictions similar to those of classical liver alcohol dehydrogenase and therefore derived from a metabolically active enzyme like other enzyme crystallins. Special residues at the active site, however, differ substantially, including an apparent lack of a zinc-binding site. This is compatible with altered functional properties and makes the spread within this medium-chain dehydrogenase family resemble the wide spread within the short-chain dehydrogenases. Schematic plotting is useful for illustrating the differences between 'variable' and 'constant' enzymes.

Alcohol Dehydrogenase↗
PubMed1993

Molecular cloning and sequencing of zeta-crystallin/quinone reductase cDNA from human liver.

Zeta-crystallin is an enzyme-crystallin highly expressed in the lens of some hystricomorph rodents and camels. It has been shown to have a novel NADPH: quinone oxidoreductase activity and is present at enzymatic levels in a variety of tissues from various mammals. We report here the cDNA cloning of zeta-crystallin from a human liver library. One clone with the complete open reading frame was obtained. Ten nucleotides of the 5' and 796 of the 3' nontranslated regions are present in the clone including two possible polyadenylation signals. The deduced amino acid sequence is 328 residues long with a calculated molecular mass of 34910 daltons and isoelectric point of 8.73. It shows 84% identity with the guinea pig protein.

Amino Acid Sequence↗
PubMed1993

Ductular proliferation and hepatic secretory function in experimental fascioliasis.

Proliferation of bile duct-like epithelial cells is a common feature of extrahepatic biliary obstruction and it is also present in other forms of liver disease. Experimental infestation with Fasciola hepatica induces hyperplasia of ductular cells together with different functional alterations, such as hypercholeresis, in the rat. We have investigated the contribution of ductular biliary secretion to the hypercholeretic phenomenon in rats with experimental fascioliasis. Infestation was induced by oral administration of 20 metacercariae of F. hepatica. Twelve weeks later, histological study of the liver showed a hyperplastic reaction with proliferation of bile duct-like structures. Basal bile flow in infested animals was significantly higher than that of control animals (+17%), while biliary secretion of bile acids did not significantly differ between both groups. Bile flow increase was associated in parasitized animals with a significantly lower [14C]mannitol bile:plasma ratio (-23%). Intravenous secretin administration (0.3 CU/100 g body wt min) induced a significant increase in the biliary concentration of bicarbonate (+21%) and an enhancement of bile flow (+21%) only in the animals with ductular proliferation. Taurocholate infusion (0.5 nmol/100 g body wt min) produced a similar bile flow increase both in control rats and in rats with proliferated biliary ductules. These results indicate that proliferated bile ductules and ducts spontaneously secrete bile in response to infestation by F. hepatica and that secretin-stimulated bile flow originates at the proliferated biliary structures.

Animals↗
PubMed1993

Carbonyl-metabolizing enzymes and their relatives recruited as structural proteins in the eye lens.

The refractive properties of the eye lens are determined by abundant soluble structural proteins known as crystallins. While some crystallins are common to most vertebrates, others are abundant only in groups of related species. These taxon-specific crystallins all turn out to be enzymes, apparently recruited by modification of gene expression without prior gene duplication. They include eta-crystallin, accounting for up to 25% of protein in elephant shrew lenses and apparently identical to cytoplasmic aldehyde dehydrogenase; rho-crystallin from frog lenses, a member of the same superfamily as aldose and aldehyde reductases; and zeta-crystallin, found in guinea pig and camel lenses, which is structurally related to alcohol dehydrogenase (ADH). Unlike ADH, zeta-crystallin requires NADPH rather than NAD+/NADH as cofactor. Molecular modelling of zeta-crystallin shows that amino-acid changes around the co-factor binding site are responsible for this change in affinity. Purified guinea pig lens zeta-crystallin has a substrate preference for orthoquinones which are reduced by a single electron transfer mechanism. cDNA sequencing of zeta-crystallin suggests that the expression in lens as a crystallin depends on a different gene promoter from that used predominantly in liver. The putative guinea pig zeta-crystallin lens promoter has now been assayed for function in transfection studies. Elements with positive and negative effects on transcription, at least one of which has tissue preferred function, have been defined. When introduced into transgenic mice this promoter exhibits tissue-specific expression in the lens. This is the first identification of a lens-specific, alternative promoter in an enzyme crystallin gene.

Aldehyde Dehydrogenase↗
PubMed1993

The Glasgow Coma Scale and prognosis in gunshot wounds to the brain.

To determine which factors predict survival in patients with gunshot wounds to the brain, 192 patients who had intracranial injury demonstrated on computed tomographic (CT) scanning were retrospectively reviewed. Glasgow Coma Scale (GCS) scores on admission seemed to be the most important factor in predicting survival. Age, the presence of extruded brain, and use of a shotgun could not be shown to be factors independent of admission GCS score. Findings on CT scans (single lobe vs. multilobe involvement) helped to predict survival only in patients with GCS scores 5-13. The mortality rate was 35%. Among survivors 18% had brain-related long-term disability, and an additional 27% had long-term disability related to associated eye injury.

Adolescent↗
PubMed1992

Sideroblastic anemia. A diagnosis to consider in alcoholic patients.

Alcoholic patients who present with anemia can pose a diagnostic challenge. Although deficiencies of iron, vitamin B12, and folate commonly result in anemia, bone marrow suppression of red blood cell production related to the direct toxic effects of alcohol can cause a form called sideroblastic anemia. This case report describes a patient presenting with acute alcohol intoxication and anemia in whom extensive evaluation revealed a hematologic picture compatible with acquired sideroblastic anemia.

Alcoholism↗
PubMed1992

A guinea-pig hereditary cataract contains a splice-site deletion in a crystallin gene.

A congenital cataract present in guinea pigs provided a unique opportunity to study a hereditary lens disease at the molecular level. zeta-Crystallin, one of the most abundant guinea pig lens proteins, was found to be altered in the lens of cataractous animals. Several zeta-crystallin cDNA clones were isolated from a cataractous lens library and found to contain a 102-bp deletion towards the 3' end of the coding region. This deletion does not interfere with the reading frame but results in a protein 34 amino acids shorter. Sequence analysis of a normal genomic zeta-crystallin clone revealed that the missing 102-bp fragment corresponds to an entire exon (exon 7). PCR analysis of the genomic DNA isolated from cataractous animals showed that exon 7, though missing from the mRNA, is intact in the cataractous genome. Further sequence analysis of the zeta-crystallin gene disclosed a dinucleotide deletion of the universal AG at the acceptor splice-site of intron 6 of the mutant gene. The presence of this mutation results in the skipping of exon 7 during the mRNA processing which in turn results in the altered zeta-crystallin protein. This is the first time a genomic mutation in an enzyme/crystallin gene has been directly linked to a congenital cataract.

Animals↗
PubMed1992

Nodular regenerative hyperplasia in the rat induced by a selenium-enriched diet: study of a model.

Weaned male rats were fed a 4 ppm selenium diet. Compared after 2 mo with a control group fed a 0.4 ppm diet, the rats' body weights had not significantly decreased and liver function was normal, but portal pressure was 1.8 times higher (p less than 0.05). Liver weight was slightly increased (10.3%; p less than 0.05). All livers had an abnormal appearance. In the less severe cases the surface was only slightly irregular, but in the more severe cases, atrophic micronodular lobes and hypertrophic lobes, with mildly irregular surfaces, were present. On light microscopy, atrophic lobes displayed a peripheral nodular zone with micronodules separated by rows of atrophic hepatocytes without fibrosis, characteristic of nodular regenerative hyperplasia, and a central atrophic zone that was sometimes peliotic. Hypertrophic lobes and livers in the less severe cases had only minor and relatively localized evidence of nodular regenerative hyperplasia; occasional peliosis was seen. In all cases portal veins, hepatic veins and hepatic arteries were normal. By electron microscopy, in nonnodular zones with no obvious evidence of parenchymal atrophy, the endothelial wall showed signs of complete or incomplete capillarization with frequent enlargement of the Disse space. The selenium-enriched diet is a reproducible model of liver nodular regenerative hyperplasia. In this model, damage to the sinusoidal wall could represent the primum movens of microcirculatory disturbances.

Animals↗
PubMed1992

Alterations induced by fascioliasis and cirrhosis on the biliary excretion of cefmetazole in Wistar rats.

1. Alterations induced by fascioliasis and cirrhosis on the biliary excretion of cefmetazole have been studied in Wistar rats. 2. Both infestation with Fasciola hepatica and experimental cirrhosis originated a significant decrease in the biliary excretion and in bile flow increase induced by the drug. 3. Administration of the beta-lactam antibiotic induced a lower degree of uncoupling of biliary lipid secretion in the cirrhotic and fasciolotic animals, but the effect was evident in all experimental groups.

Animals↗
PubMed1992

Noninvasive percutaneous induction of topical analgesia by a new type of drug carrier, and prolongation of local pain insensitivity by anesthetic liposomes.

We studied the duration of action and permeability of common analgesics and local anesthetics applied dermally via new carriers--transfersomes--in rats and humans. The therapeutic potential of analgesic transfersomes was evaluated in Sprague-Dawley rats subjected to heat and pressure stimuli. Results were compared with those obtained from administration of lidocaine-containing standard liposomes. In rats, subcutaneous injections of 2% lidocaine solution and of liposomal or transfersomal suspension resulted in a strong initial analgesic effect that decayed within 6-7 min. Characteristic withdrawal time is approximately 30 s. Dermally applied analgesic transfersomes, by contrast, increased heat stimulus reaction to greater than 70 s, 130% longer than in controls that received a placebo or a standard aqueous lidocaine solution. In humans, we tested two groups of nine male and female volunteers, aged between 25 and 60 yr, for pain-suppressing activity assessed by the pinprick method. Each subject received a total of 0.5 mL of a transfersomal preparation containing 7% lidocaine or 4% tetracaine over a forearm area of 9 cm. We conclude that the effectiveness of dermally applied anesthetic transfersomes is similar to that of the corresponding subcutaneous injections of similar drug quantities and that optimally designed transfersomes offer a suitable and promising means for the noninvasive treatment of local pain with direct, topical drug application.

Administration, Cutaneous↗
PubMed1992

Assessing the loneliness of workers with mental retardation.

This study was designed to determine whether a reliable instrument could be developed to measure the loneliness experienced by workers with mental retardation. In addition, supervisors were asked to rate subjects on loneliness and four other behavioral subtypes in order to determine whether there was a relation between these ratings and the loneliness questionnaire. Three groups of subjects were assessed: persons with mild, moderate, and severe mental retardation. Results indicated that the Worker Loneliness Questionnaire was a reliable instrument for use with persons with mild and moderate mental retardation. In addition, the results showed that some individuals were lonely; however, this was not a pervasive feeling. The implications for measuring the self-perceptions of individuals with mental retardation were discussed.

Adult↗