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Biomedical subjects

M Pineda

Publications and source records attributed to M Pineda.

At least 91 records · Page 5Linked to original sources
PubMed1994

[Validity of 6 indirect methods to assess treatment compliance in arterial hypertension].

BACKGROUND: For adequate control of high blood pressure (HBP) the therapy indicated must be correct, with effective medication which must be taken as required. At a collective level methods to evaluate patients' compliance of the above are necessary since without the same the efficacy of the drugs cannot be determined. In this study methods allowing the clinic to easily quantify patient fulfillment were sought. METHODS: Six indirect methods were used to evaluate therapeutic compliance: 1) self communicated compliance (SC), 2) appointment attendance (AA), 3) degree el control obtained in the blood pressure (DC), 4) Morinsky and Green tests (M-G), 5) patient's knowledge of the disease (PK) and 6) doctor's judgement on patient's compliance (DJ). All the above were applied to 152 hypertense patients randomly selected from the Health Centers of Alfaz and Alicante (Spain). Concordance with the compliance obtained from the "counting of tablets" in the patient's home and by surprise were evaluated by double entry tables. RESULTS: The SC is the method which obtains greatest specificity (96.7%), exactness (73%), probability of low compliance (88%) and percent of probability of low compliance (11.3%). The PK had greatest sensitivity (83.3%) and greater probability of high compliance (83.6%) and percentage of probability of high compliance (0.3%). The SC (23.1%), AA (1.3%) and the DJ (7.5%), overestimate good compliance. The M-G test (7.9%) and the PK (20.4%) overestimate had compliance. CONCLUSIONS: In this study self communicated compliance and patient's knowledge of disease were the methods which provided the best indicators of validity to measure therapeutic compliance in high blood pressure in outpatients, although there is the inconvenience of significantly over and under estimating good and bad compliance.

Evaluation Studies as Topic↗
PubMed1993

[Results of 5 campaigns to detect previously unidentified cases of hypertension].

OBJECTIVE: To find the efficacy of two methods of detecting previously unknown hypertension--systematic taking of blood pressure (ST) and the Mobile Unit (MU)--and to evaluate the over-diagnosis of arterial hypertension (AHT) in crossover studies which only use epidemiological criteria (EC). DESIGN: A descriptive study with population and opportunist strategies. An operative MU team attended commercial and work centres within the chosen area. ST looked for AHT in patients attending Health Centre clinics. INTERVENTION: EC in screening, in line with WHO guidelines and clinical confirmation (CC) in the Health Centres. SETTING: MU in the catchment areas of Novelda, Carrús and C. Jardin Health areas. ST in the San Miguel de Salinas and C. Jardin Health Centres. PATIENTS: 1654 people over 19 with the MU and 4138 through ST. RESULTS: Both methods discovered more hypertension in men (MU p = 0.009 and ST p = 0.000) and in the 20 to 39 age group (MU p = 0.000 and ST p = 0.000). EC led to over-diagnosis (5.8% MU and 6.3% ST); greater in men (6.6% and 6.5%) and +/- 60 years old (8.7% and 7.5%). Positive predictive values obtained were 59.8% with MU and 47.4% with ST. CONCLUSIONS: Both methods are useful ways of identifying people suffering hypertension: both young people and men. But CC is essential in order to make a real diagnosis of AHT. Out of every 10 people detected by using EC, only 5 were confirmed by ST and 6 by MU. This information must be borne in mind when evaluating the the prevalence of AHT in epidemiological studies.

Adult↗
PubMed1993

[Diagnosis of ornithine carbamoyl transferase deficiency and heterozygote detection with allopurinol loading test].

BACKGROUND: Allopurinol loading test is based on the inhibition of pyrimidine biosynthesis and the subsequent increase in orotic acid excretion caused by a single dose of allopurinol. Abnormally elevated amounts of orotic acid excretion are demonstrated in ornithine carbamoyl transferase (OCT) deficiency patients and heterozygotes as well as in other disorders of urea cycle. Biochemical studies performed for the diagnosis of one patient and carrier detection in her family are presented. METHODS: Amino acids: ion exchange chromatography; ammonium: method of Van Anken and Shiphorst; orotic acid: modification of Adachi et al, and allopurinol test following Brusilow et al. RESULTS: The characteristic amino acid profile of the patient together with her clinical history suggested the diagnosis of OCT deficiency, which was confirmed with protein and allopurinol loading test. The heterozygote condition became evident only by means of allopurinol test in 2/5 female relatives. CONCLUSIONS: Allopurinol test is a useful tool for the preliminary investigation of urea cycle function, avoiding the possible hyperammonemia caused by other test, and permitting extensive familial studies without hospitalization. It results more informative than the protein loading test.

Allopurinol↗
PubMed1993

Docosahexaenoic acid--a new therapeutic approach to peroxisomal-disorder patients: experience with two cases.

Docosahexaenoic acid (DHA, 22:6 omega 3) is a major constituent of brain membrane phospholipids and photoreceptor cells. Patients with generalized peroxisomal disorders have extremely low levels of DHA in the brain and other tissues. Since a DHA deficiency could explain some basic symptoms in peroxisomal-disorder patients, we tested the possible beneficial effects of DHA in two patients with neonatal adrenoleukodystrophy (NALD). Before the treatment, both patients had very low DHA levels in plasma and erythrocytes. We first gave DHA in the form of fish oil and, in both patients, the rapid increase in red-cell DHA levels indicated that this fatty acid was being absorbed and incorporated into membrane phospholipids very fast. However, a low ratio 22:6 omega 3/22:5 omega 3 was still present in erythrocyte membranes, and the content of 20:5 omega 3 (eicosapentaenoic acid) was too high with the fish oil diet. We then began treatment with pure DHA ethyl ester and, after a few weeks, erythrocyte omega 3 polyunsaturated fatty acids were normal. There was an increase in the 18:0 molecular species of plasmalogens in both patients, most significantly in the child with affected plasmalogen biosynthesis in cultured fibroblasts. In the less severely affected NALD patient, treatment with DHA produced a very significant decrease in the ratios 24:1/22:0 and 26:1/22:0, and this child improved neurologically. The present data suggest that DHA deficiency may be the cause for some of the most characteristic abnormalities in peroxisomal-disorder patients and open new therapeutic possibilities for these patients.

Child↗
PubMed1992

Purification and substrate inactivation of xanthine dehydrogenase from Chlamydomonas reinhardtii.

Xanthine dehydrogenase (XDH) from the unicellular green alga Chlamydomonas reinhardtii has been purified to electrophoretic homogeneity by a procedure which includes several conventional steps (gel filtration, anion exchange chromatography and preparative gel electrophoresis). The purified protein exhibited a specific activity of 5.7 units/mg protein (turnover number = 1.9 .10(3) min-1) and a remarkable instability at room temperature. Spectral properties were identical to those reported for other xanthine-oxidizing enzymes with absorption maxima in the 420-450 nm region and a shoulder at 556 nm characteristic of molybdoflavoproteins containing iron-sulfur centers. Chlamydomonas XDH was irreversibly inactivated upon incubation of enzyme with its physiological electron donors xanthine and hypoxanthine, in the absence of NAD+, its physiological electron acceptor. As deduced from spectral changes in the 400-500 nm region, xanthine addition provoked enzyme reduction which was followed by inactivation. This irreversible inactivation also took place either under anaerobic conditions or whenever oxygen or any of its derivatives were excluded. Adenine, 8-azaxanthine and acetaldehyde which could act as reducing substrates of XDH were also able to inactivate it upon incubation. The same inactivating effect was observed with NADH and NADPH, electron donors for the diaphorase activity associated with xanthine dehydrogenase. In addition, partial activities of XDH were differently affected by xanthine incubation. We conclude that xanthine dehydrogenase inactivation by substrate is due to an irreversible process affecting mainly molybdenum center and that sequential and uninterrupted electron flow from xanthine to NAD+ is essential to maintain the enzyme in its active form.

Acetaldehyde↗
PubMed1992

Abnormal local-circuit neurons in epilepsia partialis continua associated with focal cortical dysplasia.

A limited cortical resection including the rolandic fissure and the pre- and postcentral cortical regions was carried out in a patient suffering from epilepsia partialis continua resistant to antiepileptic drugs. The histological examination revealed several foci of very large neurons distributed with no laminar organization in the depth of the rolandic fissure and in the crown of the primary motor and primary somatosensory areas; these lesions were consistent with focal cortical dysplasia. In addition, decreased numbers of neurons, astrocytosis and proliferation of capillaries, compatible with chronic tissue necrosis, were found in the inferior regions of the banks of the rolandic fissure. Subpopulations of local-circuit neurons were examined with parvalbumin, calbindin D-28k and somatostatin immunocytochemistry. Focal areas of cortical dysplasia contained abnormal immunoreactive neurons. Huge parvalbumin-immunoreactive cells were distributed at random and resembled axo-axonic (chandelier) and basket neurons. Abnormal calbindin D-28k-immunoreactive cells were reminiscent of double-bouquet neurons and multipolar cells. Very large somatostatin-immunoreactive cells were seldom observed in the dysplastic foci. On the other hand, areas of tissue necrosis displayed massive reduction of immunoreactive cells and fibers. Abnormalities in the morphology and distribution of local-circuit (inhibitory) neurons observed here for the first time in focal cortical dysplasia may have a pivotal role in the appearance and prolongation of electrical discharges and continuous motor signs in human focal epilepsy.

Adolescent↗
PubMed1991

Purification and molecular properties of urate oxidase from Chlamydomonas reinhardtii.

Urate oxidase (urate: oxygen oxidoreductase, EC 1.7.3.3) from the unicellular green alga Chlamydomonas reinhardtii has been purified to electrophoretic and immunological homogeneity by a procedure which includes as main steps ammonium sulfate fractionation, gel filtration, ion exchange and xanthine-agarose affinity chromatography. The native enzyme has a relative molecular mass (Mr) of 124,000 and consists of four identical or similar-sized subunits of Mr 31,000 each. The enzyme has a Stokes's radius of 3.87 nm, a sedimentation coefficient of 6.8 S and an f/f0 of 1.23, and exhibits its maximal absorption at 276 nm. Optimum pH was 8.5 and maximum activity was shown at 40 degrees C, with an activation energy of 53 kJ.mol-1 and a Q10 of 1.96. Absorption spectrum of native reduced enzyme showed two transient maxima at 392 and 570 nm, very similar to those of metal-urate complexes, which disappeared in the presence of cyanide. Inhibition by cyanide and neocuproin, but not by salicylhydroxamic acid, strongly suggests that copper is the metal involved in enzymatic urate oxidation. By using a sensitive photokinetic method for copper determination, a content of 4 mol of copper per mol of enzyme has been found.

Calorimetry↗
PubMed1991

Distinction between Hypoxanthine and Xanthine Transport in Chlamydomonas reinhardtii.

Chlamydomonas reinhardtii cells consumed hypoxanthine and xanthine by means of active systems which promoted purine intracellular accumulation against a high concentration gradient. Both uptake and accumulation were also observed in mutant strains lacking xanthine dehydrogenase activity. Xanthine and hypoxanthine uptake systems exhibited very similar Michaelis constants for transport and pH values, and both systems were induced by either hypoxanthine or xanthine. However, they differed greatly in the length of the lag phase before uptake induction, which was longer for hypoxanthine than for xanthine. Cells grown on ammonium and transferred to hypoxanthine media consumed xanthine before hypoxanthine, whereas cells transferred to xanthine media did not take up hypoxanthine until 2 hours after commencing xanthine consumption. Metabolic and photosynthetic inhibitors such as 2,4-dinitrophenol, 3-(3,4-dichlorophenyl)-1,1-dimethyl urea, and carbonylcyanide m-chlorophenylhydrazone inhibited to a different extent the hypoxanthine and xanthine uptake. Similarly, N-ethylmaleimide abolished xanthine uptake but slightly affected that of hypoxanthine. Hypoxanthine consumption was inhibited by adenine and guanine whereas that of xanthine was inhibited only by urate. We conclude that hypoxanthine and xanthine in C. reinhardtii are taken up by different active transport systems which work independently of the intracellular enzymatic oxidation of these purines.

Journal Article↗
PubMed1990

Nuclear factors interact with conserved A/T-rich elements upstream of a nodule-enhanced glutamine synthetase gene from French bean.

The gln-gamma gene, encoding the gamma subunit of glutamine synthetase in French bean (Phaseolus vulgaris), is strongly induced during nodule development. We have determined the nucleotide sequence of a 1.3-kilobase region at its 5' end and have identified several sequences common to the promoter regions of late nodulin genes from other legume species. The 5'-flanking region was analyzed for sequence-specific interactions with nuclear factors from French bean. A factor from nodules (PNF-1) was identified that binds to multiple sites between -860 and -154, and a related but distinct factor (PRF-1) was detected in extracts from uninfected roots. PNF-1 and PRF-1 bound strongly to a synthetic oligonucleotide containing the sequence of an A/T-rich 21-base pair imperfect repeat found at positions -516 and -466. The same factors also had a high affinity for a protein binding site from a soybean leghemoglobin gene and appeared to be closely related to the soybean nodule factor NAT2, which binds to A/T-rich sequences in the lbc3 and nodulin 23 genes [Jacobsen et al. (1990). Plant Cell 2, 85-94]. Comparison of NAT2/PNF-1 binding sites from a variety of nodulin genes revealed the conservation of the short consensus core motif TATTTWAT, and evidence was obtained that this sequence is important for protein recognition. Cross-recognition by PNF-1 of a protein binding site in a soybean seed protein gene points to the existence of a ubiquitous family of factors with related binding affinities. Our data suggest that PNF-1 and PRF-1 belong to an evolutionarily conserved group of nuclear factors that interact with specific A/T-rich sequences in a diverse set of plant genes. We consider the possible role of these factors in coregulating the expression of gln-gamma and other late nodulin genes.

Amino Acid Sequence↗
PubMed1987

Primary degeneration of the granular layer of the cerebellum (Norman type). A Golgi study.

Purkinje cells, impregnated with the rapid Golgi method, in a patient with primary degeneration of the granular layer showed abnormal orientation of the perikaryon and dendrites, reduction in size of the dendritic arbor, absence of spiny branchlets, and large numbers of stubby spines and hypertrophic spines on secondary dendritic branches; stubby spines and thorn-like formations were seldom observed on the primary dendrites and perikaryon of some Purkinje cells. These findings are similar to those described in the cerebellum of the homozygous weaver mutant mouse and in the cerebella of experimentally induced agranular phenocopies, thus suggesting that similar plastic changes occur in human and animal Purkinje cells as a result of the absence of parallel fibres input in early developmental stages. In addition, Purkinje cells in this patient showed club-shaped deformities in the distal region of primary dendrites, which were filled with radially oriented, short dendrites covered with stubby spines and hypertrophic spines. These latter structures appear to be fully impregnated asteroid bodies observed in paraffin sections.

Adolescent↗
PubMed1987

A new family affected by the syndrome of hyperornithinaemia, hyperammonaemia and homocitrullinuria.

We have reported three cases of hyperornithinaemia associated with hyperammonaemia and homocitrullinuria (HHH). They deal with two brothers and a sister from a family where the parents and four other children are healthy on clinical and biochemical examination. The biochemical findings in our patients indicate the existence of a defect in the transport of ornithine into the mitochondria. Cultured skin fibroblasts from two of these patients incorporated six times less [14C]ornithine into protein as compared to control cells. The most characteristic sign of the clinical picture is the progressive spastic paraparesis found in one of the cases. Ornithine supplementation and restricted protein intake may be useful in the treatment of this syndrome since after three years of treatment the clinical response was favourable and the patients showed no adverse clinical effects.

Adolescent↗
PubMed1987

Comparative kinetic behaviour and regulation by fructose-1,6-bisphosphate and ATP of pyruvate kinase from erythrocytes, reticulocytes and bone marrow cells.

1. Kinetic and regulatory properties of pyruvate kinase have been studied in haemolysates of erythrocytic populations from blood and bone marrow of rats. 2. Pyruvate kinase from normal rat erythrocytes showed sigmoidal kinetics vs phosphoenolpyruvate. In contrast, the enzyme from reticulocytes and erythroid-rich bone marrow cells behaved as hyperbolic. 3. The enzyme activities were always inhibited by ATP. Activation by fructose-1,6-bisphosphate was only observed in erythrocytes. 4. These kinetic differences suggest changes in pyruvate kinase isozymes in cells of the erythrocytic line of rats.

Adenosine Triphosphate↗
PubMed1987

Relation between tolerance to ethanol and alcohol dehydrogenase (ADH) activity in Drosophila melanogaster: selection, genotype and sex effects.

The suggestion of Oakeshott et al. (1984) that selection at the Adh locus, as a response to ethanol, is restricted to D. melanogaster laboratory-adapted populations, is tested in this paper with the "Lagar de los Reyes" (LR) lines. For this purpose, homozygous lines for the AdhF and the AdhS alleles were maintained on food supplemented with ethanol. After the selection, the ethanol tolerance and the ADH activity of the selected flies (LRSeF and LRSeS) were determined and compared with those of the control flies (LRCF and LRCS), maintained on standard medium. Then, the effects of the selection, genotype and sex, and the relation between ethanol tolerance and ADH activity were analysed. Our results fail to show a consistent correlation between ethanol tolerance and ADH activity in the adults of LR lines. Our findings also indicate that adaptation of D. melanogaster to ethanol-containing food could be accomplished without significant changes on the ADH activity in the adults. The possibility that the adaptation of D. melanogaster to environmental ethanol could be independent of the Adh locus is discussed.

Alcohol Dehydrogenase↗
PubMed1986

[Type C Niemann-Pick disease in 2 siblings. Biochemical bases of its diagnosis].

Two brothers, a seven-year-old male and a nine-year-old female are reported. Clinical features include scholar troubles and clumsiness, hepatosplenomegaly, vertical supranuclear ophthalmoplegia and ataxic gait. Moreover, the girl showed intention tremor. Foamy histiocytes were seen in bone marrow and some Niemann-Pick type Kupffer cells were present in liver. Girl's conjunctival biopsy showed lamellar inclusions. Biochemical studies were performed in girl's skin and liver biopsies. Sphingomyelinase activity assayed with 14C sphingomieline in cultured skin fibroblasts was 26% at the mean control value. Liver lipid composition did not show an appreciable increase of sphingomyelin or cholesterol, but bis (monoacylglyceryl) phosphate was clearly elevated. These data are compatible with Niemann-Pick disease type C.

Child↗
PubMed1984

Changes in enzyme activities involved in the degradation of 1,3-bisphosphoglycerate during erythropoiesis in rat bone marrow.

Rat bone marrow cells have been fractionated by density gradient in Percoll. Differential counting of erythroid cells, haemoglobin concentration and bisphosphoglycerate mutase and phosphoglycerate kinase activities have been determined in cellular fractions. As shown by means of a statistical approach, an increase in bisphosphoglycerate mutase activity and a slight decrease in phosphoglycerate kinase activity is found in erythroid cells as their haemoglobin content increases. Our results suggest that there is a synthesis of 2,3-bisphosphoglycerate during the erythropoietic process which parallels the synthesis of haemoglobin.

Animals↗
PubMed1984

[Considerations on neonatal epileptic encephalopathies apropos of a personal case].

Studies were done on a newborn with tonic status seizures beginning at 15 days old to his death at 3 months of age. The clinical features were: (1) important psychomotor retardation; (2) tonic seizures consisting of flexion or extension of the upper limbs and head, ocular revulsion, facial cyanosis and respiration troubles. The seizure mean duration was from 4 to 6 sec. The seizures appeared sometimes isolated, sometimes in bursts with an increasing frequency but not related to the nycthemeral cycle. In the EEG there appears a 'burst-suppression' pattern which persists continuously whether the patient was asleep or awake. The clinical and electroencephalographic findings suggest Ohtahara's syndrome. Some considerations are made about the clinical, electroencephalographic and aetiologic findings of the several epileptic encephalopathies with suppression bursts in the newborn.

Brain Diseases↗