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R Morales

Publications and source records attributed to R Morales.

At least 37 records · Page 2Linked to original sources
PubMed2000

A redox-dependent interaction between two electron-transfer partners involved in photosynthesis.

Ferredoxin:NADP+:reductase (FNR) catalyzes one terminal step of the conversion of light energy into chemical energy during photosynthesis. FNR uses two high energy electrons photoproduced by photosystem I (PSI) and conveyed, one by one, by a ferredoxin (Fd), to reduce NADP+ to NADPH. The reducing power of NADPH is finally involved in carbon assimilation. The interaction between oxidized FNR and Fd was studied by crystallography at 2.4 A resolution leading to a three-dimensional picture of an Fd-FNR biologically relevant complex. This complex suggests that FNR and Fd specifically interact prior to each electron transfer and disassemble upon a redox-linked conformational change of the Fd.

Anabaena↗
PubMed2000

Crystallographic studies of the interaction between the ferredoxin-NADP+ reductase and ferredoxin from the cyanobacterium Anabaena: looking for the elusive ferredoxin molecule.

Ferredoxin-NADP(+) reductase (FNR) and its physiological electron donor ferredoxin (Fd) from the cyanobacterium Anabaena PCC7119 have been co-crystallized. The unit-cell parameters are a = b = 63.72, c = 158.02 A and the space group is P2(1)2(1)2(1). The crystal structure has been solved with 2.4 A resolution synchrotron data by molecular replacement, anomalous dispersion and R(min) search methods. For the computations, the crystal was treated as a merohedral twin. The asymmetric unit contains two FNR molecules and one ferredoxin molecule. The packing of the FNR molecules displays a nearly tetragonal symmetry (space group P4(3)2(1)2), whereas the ferredoxin arrangement is orthorhombic. This study provides the first crystallographic model of a dissociable complex between FNR and Fd.

Anabaena↗
PubMed2000

[Incomplete sagittal septum of the bladder].

OBJECTIVE: To describe an additional case of incomplete sagittal septum of the bladder. METHODS: A case of incomplete sagittal septum of the bladder in a young, asymptomatic patient with paralysis of both lower limbs is presented and literature is briefly reviewed. RESULTS: The diagnosis was made by intravenous urography performed five years after the accident that had caused the paralysis. Radiological evaluation showed an "apple heart" bladder with reduced capacity. No treatment was required. CONCLUSIONS: Incomplete sagittal septum of the bladder is rare. To our knowledge, only 7 cases have been previously reported. Incomplete sagittal septum is like complete septum, but both cavities communicate anteriorly or distally, according to the direction and depth the septum protrudes into the bladder.

Adult↗
PubMed1999

Refined X-ray structures of the oxidized, at 1.3 A, and reduced, at 1.17 A, [2Fe-2S] ferredoxin from the cyanobacterium Anabaena PCC7119 show redox-linked conformational changes.

The chemical sequence of the [2Fe-2S] ferredoxin from the cyanobacterium AnabaenaPCC7119 (Fd7119) and its high-resolution X-ray structures in the oxidized and reduced states have been determined. The Fd7119 sequence is identical to that of the ferredoxin from the PCC7120 strain (Fd7120). X-ray diffraction data were collected at 100 K with an oxidized trigonal Fd7119 crystal, at 1.3 A resolution, and with an orthorhombic crystal, previously reduced with dithionite and flash frozen under anaerobic conditions, at 1.17 A resolution. The two molecular models were determined by molecular replacement with the [2Fe-2S] ferredoxin from the strain PCC7120 (Rypniewski, W. R., Breiter, D. R., Benning, M. M., Wesenberg, G., Oh, B.-H., Markley, J. L., Rayment, I., and Holden, H. M. (1991) Biochemistry 30, 4126-4131.) The final R-factors are 0. 140 (for the reduced crystal) and 0.138 (for the oxidized crystal). The [2Fe-2S] cluster appears as a significantly distorted lozenge in the reduced and oxidized redox states. The major conformational difference between the two redox forms concerns the peptide bond linking Cys46 and Ser47 which points its carbonyl oxygen away from the [2Fe-2S] cluster ("CO out") in the reduced molecule and toward it ("CO in") in the oxidized one. The "CO out" conformation could be the signature of the reduction of the iron atom Fe1, which is close to the molecular surface. Superposition of the three crystallographically independent molecules shows that the putative recognition site with the physiological partner (FNR) involves charged, hydrophobic residues and invariant water molecules.

Amino Acid Sequence↗
PubMed1999

Medicinal and veterinary plants of El Caurel (Galicia, northwest Spain).

A study of the medicinal and veterinary plants popularly used in El Caurel region (Lugo province, northwest Spain) and their relationships is reported. We obtained data for 85 species belonging to 31 families of vascular plants. Their vernacular names, properties, preparations, mode and popular uses are presented.

Animals↗
PubMed1999

An encyclopedia of mouse genes.

The laboratory mouse is the premier model system for studies of mammalian development due to the powerful classical genetic analysis possible (see also the Jackson Laboratory web site, http://www.jax.org/) and the ever-expanding collection of molecular tools. To enhance the utility of the mouse system, we initiated a program to generate a large database of expressed sequence tags (ESTs) that can provide rapid access to genes. Of particular significance was the possibility that cDNA libraries could be prepared from very early stages of development, a situation unrealized in human EST projects. We report here the development of a comprehensive database of ESTs for the mouse. The project, initiated in March 1996, has focused on 5' end sequences from directionally cloned, oligo-dT primed cDNA libraries. As of 23 October 1998, 352,040 sequences had been generated, annotated and deposited in dbEST, where they comprised 93% of the total ESTs available for mouse. EST data are versatile and have been applied to gene identification, comparative sequence analysis, comparative gene mapping and candidate disease gene identification, genome sequence annotation, microarray development and the development of gene-based map resources.

Animals↗
PubMed1999

Role of thyroid hormone in regulation of renal phosphate transport in young and aged rats.

In the present study, we have examined the cellular mechanisms mediating the regulation of renal proximal tubular sodium-coupled inorganic phosphate (Na/Pi) transport by thyroid hormone (T3) in young and aged rats. Young hypothyroid rats showed a marked decrease in Na/Pi cotransport activity, which was associated with parallel decreases in type II Na/Pi cotransporter (NaPi-2) protein and messenger RNA (mRNA) abundance. In contrast, administration of long-term physiological and supraphysiological doses of T3 resulted in significant increases in Na/Pi cotransport activity, protein, and mRNA levels. Nuclear run-on experiments indicated that thyroid hormone regulates NaPi-2 mRNA levels by a transcriptional mechanism. In aged rats, although there were no changes in T3 serum levels (when compared with young animals), there were significant decreases in serum Pi concentration, renal Na/Pi cotransport activity, and NaPi-2 protein and mRNA abundance. These effects were mediated, at least in part, by a reduction in the transcriptional rate of the NaPi-2 gene, probably caused by, among other factors, a smaller response to the stimulatory action of T3. Compared with young rats, the old rats exhibited less sensitivity of the Na/Pi cotransporter to thyroid hormone, with-decreased effects in both hypothyroid (inhibitory) and hyperthyroid (stimulatory) animals.

Absorption↗
PubMed1998

Interferon alfa treatment of HCV RNA carriers with persistently normal transaminase levels: a pilot randomized controlled study.

Most patients with serum hepatitis C virus (HCV) RNA and persistently normal alanine transaminase (ALT) levels show histological features of mild to moderately active chronic hepatitis. Some cirrhosis has also been reported. To assess whether interferon (IFN) treatment led to long-term HCV suppression in these patients, 31 previously untreated patients (15 men, 16 women; mean age, 44 years) with serum HCV RNA, persistently normal ALT levels on at least four consecutive occasions 2 months apart, and histological features of chronic hepatitis (21 mild activity, 10 moderate activity) were randomized to receive 1FN-alpha-2a, 3 MU three times a week for 6 months (n = 16), or no treatment (n = 15). All patients were followed up for at least 6 months after treatment ended. HCV RNA was tested by nested reverse-transcription polymerase chain reaction (RT-PCR) using 5'-untranslated region complementary primers, quantified by branched-DNA assay, and typed by nested RT-PCR testing for the HCV core region. Treated and untreated patients had similar epidemiological, virological, and histological characteristics. At the end of treatment, serum HCV RNA was still detected in 15 patients (94%) and 14 controls (93%). ALT levels flared up in 10 patients receiving IFN (62%) and in 1 control (62% vs. 7%; P < .005, chi2 test). In conclusion, 6 months' treatment with IFN-alpha-2a did not eradicate HCV RNA from serum in carriers with persistently normal ALT levels but caused ALT flare-ups in two thirds of them. Until more is known about the natural history of HCV RNA carriers with normal ALT levels, these patients should not be treated with IFN.

Adult↗
PubMed1998

HCV genotypes in Northern Italy: a survey of 1368 histologically proven chronic hepatitis C patients.

BACKGROUND/AIMS: Hepatitis C virus (HCV) easily undergoes genomic changes, thus accounting for the presence of different genotypes, with different geographic distributions and different outcomes of chronic hepatitis. Type 1b is frequently found in advanced diseases; however, since this genotype is the most prevalent in older patients, the association with advanced age and severity of the disease is confounding. The aim of this study was to assess changes in the prevalence of HCV genotypes by surveying a large population of chronic hepatitis C patients in Northern Italy, and to assess if the high prevalence of genotype 1b in older patients with advanced diseases simply reflects the duration of HCV infection, rather than intrinsic biological properties of HCV. METHODS: We studied 1368 HCV-RNA positive patients, with histologically proven chronic hepatitis. Drug addiction, blood transfusions and sporadically acquired infections represented the risk factors. RESULTS: Genotype 1b, the most prevalent isolate, and genotype 2a were associated with older age, cirrhosis, sporadically-acquired infections and blood transfusion, while types 1a, 3a, and 4 were associated with younger age, chronic persistent hepatitis and drug addiction. Patients with a history of transfusions were divided into four groups depending on the period of transfusion. The prevalence of genotype 1b decreased with time. Type 3a appeared only after 1979. CONCLUSION: The severity of chronic hepatitis C could be related more to the duration of the infection rather than to the intrinsic pathogenicity of HCV genotypes.

Adolescent↗
PubMed1998

The interaction of phospholipase A2 with liposomes: an immunological approach to its study.

Porcine pancreatic phospholipase A2 (PLA2) has been incubated for 2 hours at 34 degrees C with rabbit anti-pig pancreatic PLA2 polyclonal antiserum in the absence or presence of phosphatidylcholine liposomes in different physical states. Subsequent assay of hydrolysis -triggered through addition of 5 mM Ca2+- at 34 degrees C, shows that preincubation with antiserum in the presence of 1,2-dimyristoyl-3-sn-phosphatidylcholine liquid-crystalline vesicles, renders the PLA2 activity undetectable, similarly to what is found if preincubation is carried out in the absence of liposomes. In contrast, 1,2-dipalmitoyl-3-sn-phosphatidylcholine liposomes, which at 34 degrees C are in the gel-phase, protect the enzyme from the antiserum effect. The results are consistent with a stronger binding of PLA2 to gel phase, as compared to liquid crystalline vesicles and suggest that through the physical interaction with liposomes in the gel state, the enzyme is shielded from reaction with the antibodies. Taking into account the characteristic hydrolysis profiles of vesicles in different physical states, it can be concluded that the above interpretation agrees with the proposal that PLA2-membrane association promotes the interfacial activation of the enzyme.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1998

Microcomputer decision support system for intensive care.

This article describes a computer system to support decisions in Intensive Medicine developed for a multipurpose Intensive Care Unit (13 beds and about 700 yearly patients). The system is used in a microcomputer (486DX4). Works done in this area are mentioned; and the different programs which integrate the system, the advantages of its use and the results accomplished are described. Some of the most important results are the quality increment of the medical care given, physicians' possibilities of dedicating more time to their patients, cost reductions, and improvements in the development of teaching and in the conditions to carry out research work in the Intensive Care Unit (ICU). An analysis is made of the system requirements that guarantee its integration to the Unit work, and the easy and safe use of it by the physicians and nurses.

Critical Care↗
PubMed1998

Physiological changes in the juvenile euryhaline teleost, the tilapia Oreochromis hornorum, injected with E. coli-derived homologous growth hormone.

Growth is a complex process in fish. This study was designed to test the effect of different levels of recombinant tilapia growth hormone (tiGH) injected intraperitoneally in juvenile hybrid tilapia Oreochromis hornorum. Tilapia GH cDNA was cloned from hybrid O. hornorum tilapia. The mature protein was expressed in E. coli under regulation of the phage T7 promoter. The E. coli-derived tiGH was partially purified to 67% purity and, following renaturation, was shown to be biologically active in in vivo and in vitro assays. Recombinant tiGH stimulated extracellular matrix synthesis as shown by 35S-sulfate uptake in ceratobranchial cartilage explants. Zero, 0.1, 0.5 and 2.5 µg tiGH/g body weight (gbw) were injected in tilapia, and the effects on the growth-promoting action, hepatosomatic index (HSI), and mRNA insulin-like growth factor (IGF) induction were measured. A significant increase in the body weight (P < 0.05) and length (P < 0.01) was observed in tilapia receiving 0.5 µg tiGH/gbw. However, tilapia receiving 0.1 and 2.5 µg tiGH/gbw did not show an increase in body weight and length with respect to the control group receiving BSA injections. Binding sites for the recombinant tiGH were identified in the liver. Consistent with its somatotropic actions, the IGF mRNA induction was observed in the groups injected with 0.1 and 0.5 µg tiGH/gbw (P < 0.05). No significant increase in the HSI was detected in the injected groups when compared to the control group. These results demonstrated that the injection of biologically active E. coli-derived tiGH produces physiological changes in juvenile tilapia that ultimately resulted in a growth-promoting action only at a dose of 0.5 µg tiGH/gbw.

Journal Article↗
PubMed1997

Reciprocal interaction between glutamate and dopamine in the pars reticulata of the rat substantia nigra: a microdialysis study.

We studied the interactions between glutamate and dopamine in the pars reticulata of the substantia nigra by using microdialysis in unanaesthetized rats. Increased extracellular levels of glutamate in the pars reticulata were obtained by microinjecting the muscarinic agonist carbachol into the ipsilateral subthalamic nucleus. The increase of glutamate levels was followed by increments in extracellular levels of dopamine and GABA. Increased levels of the three neurotransmitters were also observed during the administration of N-methyl-D-aspartate through the microdialysis probe. The increase in glutamate and GABA caused by N-methyl-D-aspartate was blocked by SCH 23390, a selective D1 antagonist. However, the D1 antagonist did not prevent the increase in dopamine levels. The selective D1 agonist SKF 38393, added to the microdialysis probe, increased the levels of the three neurotransmitters. However, after the lesion of the subthalamic nucleus with kainic acid, SKF 38393 increased only the level of GABA but not those of glutamate and dopamine. In addition, the lesion of the subthalamic nucleus produced a drastic (80%) fall in the extracellular levels of glutamate. These data suggest that glutamate, through N-methyl-d-aspartate receptors, stimulates the release of dopamine from dopaminergic dendrites present in the substantia nigra pars reticulata, and that dopamine in turn stimulates the release of glutamate and GABA. Both effects are mediated by D1 dopamine receptors present on subthalamonigral and striatonigral axon terminals, respectively.

Animals↗
PubMed1997

Interpretation of the TDx-FLM fluorescence polarization assay in pregnancies complicated by diabetes mellitus.

The objective of this paper is to determine the applicability of the Abbott TDx-FLM fluorescence polarization assay in pregnancies complicated by diabetes mellitus. Retrospective review of records of women with pregnancies complicated by diabetes who underwent amniocentesis for fetal lung maturity using the Abbott TDx-FLM assay within 3 days of delivery was considered. Maternal diabetic control, neonatal birth weight, Apgar scores, umbilical cord gases, admissions to Neonatal Intensive Care Unit (NICU), development of respiratory distress syndrome (RDS) were evaluated. One hundred twenty-one patients with diabetes mellitus were identified. Thirteen (10.7%) had an FLM < or = 70 mg/g and 108 patients had > or = 70 mg/g. All obstetrical and diabetic variables were similar. RDS was not observed in neonates who had an FLM of > or = 70 mg/g. One neonate had RDS (FLM = 7.2 mg/g). The TDx-FLM > or = 70 mg/g may be interpreted as mature when obtained from transabdominal amniocentesis.

Adolescent↗
PubMed1997

Epidemiology and control of egg-associated Salmonella enteritidis in the United States of America.

The isolation rate for Salmonella enterica serotype Enteritidis (SE) in humans in the United States of America (USA) increased from 1,207 sporadic isolates identified in 1976 (0.6 isolates/100,000 population) to 10,201 identified in 1995 (4.0/100,000 population). The proportion of reported Salmonella isolates which were SE increased from 5% to 25% during the same time period. In 1990, 1994, and 1995, SE was the most commonly reported reported Salmonella serotype in the USA. Much of this increase has been associated with the consumption of contaminated shell eggs. An examination of the results of a United States Department of Agriculture (USDA) survey of spent hens at slaughter and unpasteurised liquid egg at breaker plants (liquid egg processors) in 1991 and 1995 reveals an increase in the prevalence of SE isolates overall and in most regions of the USA. SE phage type 4 (pt 4), the predominant SE phage type in other parts of the world, has emerged in the egg industry in the western USA concurrent with a sharp increase in the number of sporadic human SE pt 4 isolates in California and Utah. Research on the molecular structure and virulence of SE pt 4 isolates from the USA as compared with isolates from other parts of the world (human and poultry) should be a priority. A comparison of DNA from pt 4 isolates from the USA and Europe may provide information about the potential threat to public health and poultry in the USA from this phage type. Some regional success in the reduction of human illness as a result of SE control efforts is apparent. The Pennsylvania Egg Quality Assurance Program has shown progress in reducing SE infection in participating flocks. At a national level, however, neither the incidence of human illness due to SE nor the prevalence of SE in flocks and unpasteurised liquid eggs have decreased significantly, despite the implementation of the USDA 'trace back' regulation from 1990 to 1995, and intensified efforts to educate food handlers and to enforce safe food handling practices. More effort is needed to control SE at every stage of the egg continuum, from production through to consumption. A risk-reduction approach, with barriers to the introduction and multiplication of the pathogen throughout the farm-to-table continuum, is the most practical method for reducing human illness from SE in shell eggs at present. An effective long-term solution will require interdisciplinary efforts involving government, industry, consumers, and academics. Interventions should be developed and evaluated in compliance with the potential for reducing the risk to human health and cost-effectiveness.

Animal Husbandry↗
PubMed1997

[A non-invasive test choice for the diagnosis of coronary disease in women].

BACKGROUND AND PURPOSE: Regarding coronary heart disease, women have often been excluded from clinical trials. Current practical recommendations are thus based on studies in men. To identify the non invasive technique of choice in detecting coronary artery disease in women, a study with different diagnostic tests has been undertaken. METHODS: Exercise stress test, dipyridamole echocardiography (0.84 mg/kg), dobutamine echocardiography (up to a total dose of 40 micrograms/kg per minute and atropine if necessary), MIBI-SPECT during dobutamine infusion and coronary angiography, were performed in 40 consecutive women with chest pain and no previous history of coronary artery disease. RESULTS: The four tests had similar sensitivity: exercise stress test (80%; CI 95%, 52-94), dipyridamole echocardiography (80%; CI 95%, 56-93), dobutamine echocardiography (80%; CI 95%, 56-93) and scintigraphy MIBI-SPECT (85%; CI 95%, 61-95). The specificity of dipyridamole echocardiography (100%; CI 95%, 83-100) and dobutamine echocardiography (90%; CI 95%, 67-98) was higher than that of exercise stress test (50%; CI 95%, 22-78) and MIBI-SPECT (65%; CI 95%, 41-84). The positive predictive values of dipyridamole and dobutamine echocardiography were 100% and 88% respectively. CONCLUSIONS: The feasibility of exercise stress test in women is inferior to that of the other techniques. The sensitivity of the four tests to diagnose coronary artery disease is similar. The specificity of dipyridamole echocardiography and dobutamine echocardiography is higher than that of exercise stress test and MIBI-SPECT. Stress echocardiography can be considered the non invasive technique of choice for diagnosing coronary artery disease in women.

Aged↗