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J Vidal

Publications and source records attributed to J Vidal.

At least 19 recordsLinked to original sources
PubMed1992

Regulatory phosphorylation of phosphoenolpyruvate carboxylase in protoplasts from Sorghum mesophyll cells and the role of pH and Ca2+ as possible components of the light-transduction pathway.

The light-dependent phosphorylation of the photosynthetic phosphoenolpyruvate carboxylase (PyrPC) was shown to occur in protoplasts from Sorghum mesophyll cells. It was accompanied by an increase in PyrPC protein-serine-kinase activity and conferred the target-specific functional properties, i.e. an increase in Vmax and apparent Ki for L-malate, as previously found with the whole leaf. The light-dependent regulatory phosphorylation of PyrPC was (a) specifically promoted by the weak bases NH4Cl and methylamine (agents which increase cytosolic pH), but not by KNO3, (b) inhibited by the cytosolic protein-synthesis inhibitor, cycloheximide, thus confirming that protein turnover is a component of the signal-transduction cascade, as reported in [4], (c) found to moderately decrease in the presence of EGTA and to be strongly depressed when the Ca(2+)-selective ionophore A23187 was added to the incubation medium together with EGTA. Addition of Ca2+, but not of Mg2+, to the Ca(2+)-depleted protoplasts partially, but significantly, relieved the inhibition. Calcium deprivation apparently affected the in-situ light-activation of the PyrPC protein kinase. These data indicated that both Ca2+ and an increase in cytosolic pH are required for the induction of PyrPC protein kinase activity/PyrPC phosphorylation in illuminated protoplasts from Sorghum mesophyll cells.

Amino Acid Sequence↗
PubMed1992

Site-directed mutagenesis of the phosphorylatable serine (Ser8) in C4 phosphoenolpyruvate carboxylase from sorghum. The effect of negative charge at position 8.

The properties of the dephospho and in vitro phosphorylated forms of recombinant sorghum phosphoenolpyruvate carboxylase have been compared with those of the authentic dark (dephospho) and light (phospho) leaf enzyme forms and two mutant enzymes in which the phosphorylatable serine residue (Ser8) has been changed by site-directed mutagenesis to Cys (S8C) or Asp (S8D). Kinetic analysis of the purified recombinant, mutant, and leaf enzyme forms at pH 8.0 indicated virtually identical Vmax, apparent Km (phosphoenolpyruvate), and half-maximal activation (glucose 6-P) values of about 44 units/mg, 1.1 mM, and 0.23 mM, respectively. In contrast, the Ser8, S8C, and dark leaf enzymes were about 3-fold more sensitive to inhibition by L-malate at pH 7.3 than the Ser8-P, S8D, and light leaf enzyme forms. These comparative results indicate that: (i) Ser8 is an important determinant in the regulation of sorghum phosphoenolpyruvate carboxylase activity by negative (L-malate), but not positive (glucose 6-phosphate) metabolite effectors, (ii) phosphorylation of this target residue can be functionally mimicked by Asp, but not Cys, and (iii) negative charge contributes to the effect of regulatory phosphorylation on this C4-photosynthesis enzyme.

Amino Acid Sequence↗
PubMed1992

[A change in the epidemiologic pattern of hepatitis A in Spain].

BACKGROUND: Seroepidemiologic studies carried out in different countries show that the prevalence of markers for infection by hepatitis A (HVA) is progressively decreasing in relation with improvement in the level of health care. The prevalence of anti-HVA in Catalunya and the factors related with infection by HVA were studied in order to obtain bases for designing prevention strategies adequate for the epidemiology of this infection. METHODS: Anti-HVA was determined by a method of enzyme immunoassay in a randomized sample of the general population in Catalunya. Investigation of the influence of socio/demographic variables in the prevalence of HVA infection was carried out. RESULTS: The global prevalence of anti-HVA was of 36%. In the population from 6 to 14 years of age it was of 13% and that of those over the age of 15 it was 86%. The prevalence of anti-HVA increases with age and is related with the social level of the families, the level of education and the place of birth. The incidence was higher in children of the lowest social class, in adults with the least education and in those born outside Catalunya. These factors constituted independent risk factors of HVA infection. CONCLUSIONS: The present study confirms the association between HVA infection and socio-economic factors and demonstrates that the infection is not commonly found in infancy, an increase in the number of susceptible adults is foreseeable.

Age Factors↗
PubMed1992

[The prevalence of tetanus antibodies in the adult population of Catalonia].

BACKGROUND: The aim of this study was to know the immune state of the adult population of Catalonia (Spain) versus tetanus. METHODS: The prevalence of antitetanic antibodies was determined in a representative sample (n = 604) of this population group (greater than or equal to 15 years). The technique used as that of passive hemagglutination reaction. The field work was carried out during 1989. RESULTS: 37.7% of the males and 15.7% of the females (p less than 0.001) presented titres of protector antibodies (greater than or equal to 0.01 Ul/ml) versus tetanus. The prevalence of antibodies was higher in youths of either sex and progressively descended with age. No statistically significant association was found upon performance of multivariate analysis between the sociodemographic variables (place of birth, level of education, residence, social class) and the prevalence of antibodies. CONCLUSIONS: The results of this study demonstrate that antitetanic vaccination currently being undertaken is not sufficient to insure adequate protection during adult life thus potentiating the need for the vaccination of adults in Catalonia.

Adult↗
PubMed1992

Regulatory phosphorylation of Sorghum leaf phosphoenolpyruvate carboxylase. Identification of the protein-serine kinase and some elements of the signal-transduction cascade.

The phosphoenolpyruvate (PPrv) carboxylase isozyme involved in C4 photosynthesis undergoes a day/night reversible phosphorylation process in leaves of the C4 plant, Sorghum. Ser8 of the target enzyme oscillates between a high (light) and a low (dark) phosphorylation status. Both in vivo and in vitro, phosphorylation of dark-form carboxylase was accompanied by an increase in the apparent Ki of the feedback inhibitor L-malate and an increase in Vmax. Feeding detached leaves various photosynthetic inhibitors, i.e. 3-(3,4-dichlorophenyl)-1,1-dimethylurea, gramicidin and DL-glyceraldehyde, prevented PPrv carboxylase phosphorylation in the light, thus suggesting that the cascade involves the photosynthetic apparatus as the light signal receptor, and presumably has the electron transfer chain and the Calvin-Benson cycle as components in the signal-transduction chain. Two protein-serine kinases capable of phosphorylating PPrv carboxylase in vitro have been partially purified from light-adapted leaves. One was isolated on a calmodulin-Sepharose column; it was calcium-dependent but did not require calmodulin for activity. The other was purified on a blue-dextran-agarose column and the only Me2+ required for activity was Mg2+. In reconstituted phosphorylation assays, only the latter caused the expected decrease in malate sensitivity of PPrv carboxylase suggesting that this protein is the genuine PPrv-carboxylase-kinase. Desalted extracts from light-adapted leaves possessed a considerably greater phosphorylation capacity with immunopurified dephosphorylated PPrv carboxylase as substrate than did dark extracts. This light stimulation was insensitive to type 2A protein phosphatase inhibitors, okadaic acid and microcystin-LR, which suggests that the kinase is a controlled step in the cascade which leads to phosphorylation of PPrv carboxylase. The higher phosphorylation capacity of light-adapted leaf tissue was nullified by pretreatment with the cytosolic protein synthesis inhibitor, cycloheximide. Thus, protein turnover is involved as part of the mechanism controlling the activity of the kinase purified on blue-dextran-agarose. However, no information is available with respect to the specific nature of the link between the above-mentioned light transducing steps and the protein kinase that achieves the physiological response. Finally, the in vivo phosphorylation site (Ser8) in the N-terminal region of the C4 type Sorghum PPrv carboxylase is also present in a non-photosynthetic form of the Sorghum enzyme (Ser7), as deduced by cDNA sequence analysis.

Amino Acid Sequence↗
PubMed1992

Prevalence of hepatitis B markers in the population of Catalonia (Spain). Rationale for universal vaccination of adolescents.

The prevalence of hepatitis B markers was determined in a representative sample of the general population of Catalonia (Spain). HBsAg was found in 0.5% of children (less than 15 years of age) and in 1.7% of adults (more than 15 years of age), and anti HBs in 1.6% and 18%, respectively. Age-specific prevalence for both markers showed a low risk for hepatitis B before puberty, and a progressive rise since adolescence, suggesting that perinatal transmission and horizontal transmission in children are relatively uncommon in Spain. Prevalence of hepatitis B markers was significantly higher among subjects with low education level, residing in an urban area and born outside Catalonia, but in the stratified analysis, a statistical significant difference was only maintained in the prevalence of HBV markers between those who live in urban and rural areas, and between those who were born outside Catalonia and in Catalonia. These data may be used as a basis for a strategy of hepatitis B prevention in Spain which include universal vaccination of adolescents, passive-active immunization of newborns to HBsAg positive mothers and vaccination of susceptible adults subjects from high-risk groups.

Adolescent↗
PubMed1992

Twelve cases of pituitary apoplexy.

In 12 cases of pituitary apoplexy, a preexisting unsuspected adenoma was found. The initial manifestations were sudden onset of headache (12 patients), signs of meningeal irritation (10) with fever (four), altered consciousness (12), and ophthalmologic disturbances (eight). The diagnosis was retrospective in three cases. Radiologic investigations were always suggestive if carefully considered. The plain skull roentgenograms, in particular, showed an enlarged sella turcica in 11 cases. Three patients had prolactin adenomas, and nine had nonfunctional adenomas. Medical treatment was successful in only three patients; surgery was performed in 10 cases by means of a sublabial transseptal microsurgical approach. Postoperative neurologic complications were serious in two cases. Endocrine insufficiencies were common: eight cases of permanent panhypopituitarism, two cases of pluritropic anterior pituitary dysfunction, and three cases of persistent hyperprolactinemia.

Adenoma↗
PubMed1991

[Prospective study of community-acquired pneumonias seen in a general hospital. Diagnostic errors].

BACKGROUND: The patients with community acquired pneumonias seen in an emergency service of a basic general hospital during one year were evaluated to assess their etiological, clinical and radiological features, and also to investigate the initial and final diagnosis of the disease, its evolution and the parameters associated with each microbiological type. METHODS: A medical team investigated daily the clinical records. For etiologic diagnosis, blood cultures, serological studies, urine counterimmunoelectrophoresis (CIE) and, in individualized patients, pleural fluid culture, bronchoaspirate and bronchoalveolar lavage were performed. The discordance between the initial clinical and radiological diagnosis and the microbiological results, and also the initial and final diagnostic errors were analyzed. RESULTS: 311 cases of pneumonia (150 adults and 161 children) were diagnosed. 95 (30%) had microbiological confirmation. Streptococcus pneumoniae was the most commonly isolated organism. Serologic studies were the diagnostic method with the highest yield. Complications developed in 28% of the patients and the mortality rate was 2%. There was a relationship between mortality and a high respiratory rate on admission. The initial-final diagnostic discrepancy was 43% in atypical pneumonias and 40% in bacterial pneumonias. CONCLUSIONS: Clinical parameters permitting the differentiation between atypical and bacterial pneumonia were not found. The initial diagnostic error was 12%, consisting of false positives in all instances, and the final diagnostic error included 15% false positives and 10% false negatives. Underlying diseases have a influence on the evolution of pneumonia. The mean respiratory rate on admission should be measured as a prognostic indicator. In the present study, urine CIE was a poorly sensitive method.

Adolescent↗
PubMed1991

[Usefulness of cyclosporin in the treatment of pemphigus vulgaris. Apropos of 3 cases].

Cyclosporin is a useful drug in several autoimmune diseases. It has been recently evaluated, with varying results, in several dermatoses such as pemphigus vulgaris. Three cases of this condition treated with cyclosporin are reported. The drug permitted to reduce and then to suppress prolonged corticosteroid therapy, and remission was maintained after exacerbation even in monotherapy. Hypertrichosis and gum hypertrophy were the common adverse effects.

Administration, Oral↗
PubMed1991

The phosphoenolpyruvate carboxylase gene family of Sorghum: promoter structures, amino acid sequences and expression of genes.

Two different members of the phosphoenolpyruvate carboxylase(PEPC)-encoding multigene family (clones lambda CP21 and lambda CP46) have been isolated from a Sorghum vulgare lambda EMBL4 genomic library. The use of the 3'-noncoding regions to probe Northern blots of RNA from roots, etiolated leaves and green leaves indicated that lambda CP21 and lambda CP46 encode the C3- and C4-type leaf PEPC isoforms, respectively. The lambda CP21 clone is expressed in the three tissues and is not light-regulated, whereas lambda CP46 is only expressed in greening leaves. The nucleotide sequence of the 5'-flanking DNA (520 bp) has been determined for both genes. For lambda CP46, several direct repeats were located in this region with similarities to sequences found in other light-regulated genes, but not in lambda CP21. The deduced amino acid sequences of the two S. vulgare PEPC proteins are 75% identical.

Amino Acid Sequence↗
PubMed1991

X-ray conformational study of hydrazino peptide analogues.

We have solved the crystal structures of nine pseudo-peptide analogues deriving from the hydrazino analogue of glycine or valine (N beta H2-N alpha H-C alpha HR-CO2H, R = H or iPr) or proline (N beta H2-N alpha-C alpha H-CO2H) and containing the hydrazide (CO-N beta H-N alpha less than) or N beta-Z-aminoamide [formula; see text] [CO-N alpha(N beta HZ)] peptidomimetic link. This study gives access to the average geometry of these two links, to their inter- and intramolecular interaction modes, and to their influence on the conformational properties of the molecules.

Amino Acid Sequence↗
PubMed1991

Production in Escherichia coli of active Sorghum phosphoenolpyruvate carboxylase which can be phosphorylated.

Phosphoeolpyruvate carboxylase (PEPC)-deficient mutants of Escherichia coli have been complemented with a plasmid bearing a full-length cDNA encoding the C4-type form of Sorghum leaf PEPC. Transformed cells grew on minimal medium. Two clones were selected which produce a functional and full-sized enzyme protein as determined by activity assays, immunochemical behavior and SDS-PAGE. In addition, regulatory phosphorylation of immunopurified recombinant PEPC was observed when the enzyme was incubated with a partially purified plant PEPC kinase. These results establish that E. coli cells produce a genuine, phosphate-free, higher-plant PEPC. Application of immunoadsorbtion chromatography to bacterial extracts makes it possible to prepare highly pure protein available for biochemical studies.

Cloning, Molecular↗
PubMed1991

An analysis of the diverse factors concerned with the development of pressure sores in spinal cord injured patients.

Patients with spinal cord injuries (SCI) admitted to the Institut Guttmann, Barcelona, from the years 1985 to 1988 with pressure sores (PS) are reviewed. Demographic, pathological and psychological factors are analysed in an attempt to identify organic and/or behavioural patterns which might imply an added risk for the development of pressure sores in the spinal cord injured. About 30% of 884 SCI patients admitted during this period had one or more PS (mean 1.5), most of these were localised to the ischial, trochanteric and sacral regions, and about 70% were grade 3 or 4 (Enis and Sarmiento classification). The study supports the generally acknowledged view that a precarious state of health and certain psycho-social conditions are contributing factors to a higher risk in the development and severity of PS in SCI patients.

Adult↗
PubMed1991

Carcinoma of prostatic ducts.

Carcinoma of prostatic ducts is a rare clinical feature. We have reviewed 398 histories of patients with histologic diagnosis of prostatic carcinoma and found 10 patients with the ductal variety (2.51%). Four had pure ductal transitional cell carcinoma, 5 had mixed acinar adenocarcinoma plus ductal transitional cell carcinoma, and the last one had mixed acinar and ductal adenocarcinoma. Age, symptoms, physical findings, and imaging diagnoses were similar to those of acinar carcinoma. Rectal examination disclosed hard prostate in 9 patients. The metastatic way depended on the histologic elements present in each patient. Cystoscopy showed a malignant-resembling image in 4 cases. The mean survival (23 months) was lower than that of patients with acinar carcinoma. Early diagnosis and radical surgery still are the only way to increase the expectation of life of patients affected by this pathology.

Aged↗
PubMed1991

[Treatment of obstruction caused by prostatic hypertrophy with prazosin. 1-year follow-up].

Since Caine demonstrated the presence of alpha-adrenergic receptors in prostate tissue in 1975, an alpha-blocker capable of producing maximum relaxation of prostatic tissue with minimum side effects has been sought. Prazosin, a selective alpha-1 blocking agent, must meet these requirements. We report the results of a study undertaken in 28 patients with benign hyperplasia of the prostate demonstrated by flowmetry, clinically and by ultrasound. A significant improvement was observed in all patients except for the ultrasound measured prostate size, which remained unchanged. Undesired effects were observed in 36% of the patients. Despite the initial improvement, 89.3% had abandoned treatment at 1 year principally owing to deterioration of the clinical picture and because they were submitted to surgery (the majority) or treatment with other drugs. We can conclude from our results that prazosin is useful for short-term therapy; i.e., until the patient can be referred for surgery.

Aged↗