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Biomedical subjects

F Gallardo

Publications and source records attributed to F Gallardo.

At least 37 records · Page 2Linked to original sources
PubMed1998

Purification and characterization of NADP+-linked isocitrate dehydrogenase from scots pine . Evidence for different physiological roles of the enzyme in primary development

NADP+-isocitrate dehydrogenase (NADP+-IDH; EC 1.1.1.42) is involved in the supply of 2-oxoglutarate for ammonia assimilation and glutamate synthesis in higher plants through the glutamine synthetase/glutamate synthase (GS/GOGAT) cycle. Only one NADP+-IDH form of cytosolic localization was detected in green cotyledons of pine (Pinus spp.) seedlings. The pine enzyme was purified and exhibited molecular and kinetic properties similar to those described for NADP+-IDH from angiosperm, with a higher catalytic efficiency (10(5) M-1 s-1) than the deduced efficiencies for GS and GOGAT in higher plants. A polyclonal antiserum was raised against pine NADP+-IDH and used to assess protein expression in the seedlings. Steady-state levels of NADP+-IDH were coordinated with GS during seed germination and were associated with GS/GOGAT enzymes during chloroplast biogenesis, suggesting that NADP+-IDH is involved in the provision of carbon skeletons for the synthesis of nitrogen-containing molecules. However, a noncoordinated pattern of NADP+-IDH and GS/GOGAT was observed in advanced stages of cotyledon development and in the hypocotyl. A detailed analysis in hypocotyl sections revealed that NADP+-IDH abundance was inversely correlated with the presence of GS, GOGAT, and ribulose-1,5-bisphosphate carboxylase/oxygenase but was associated with the differentiation of the organ. These results cannot be explained by the accepted role of the enzyme in nitrogen assimilation and strongly suggest that NADP+-IDH may have other, as-yet-unknown, biological functions.

Journal Article↗
PubMed1998

Increased resistance to quinolones in Campylobacter jejuni: a genetic analysis of gyrA gene mutations in quinolone-resistant clinical isolates.

Campylobacter jejuni is a frequent cause of enteritis and sometimes it requires antimicrobial therapy. We have studied the evolution of resistance to nine antibiotics from 1990 to 1994 and investigated how frequently gyrA mutations are involved in the acquisition of quinolone resistance. The percentage of chloramphenicol-, clindamycin-, tetracycline- and amoxicillin plus clavulanic acid-resistant strains has remained practically unchanged and erythromycin and gentamicin resistance has decreased, whereas the percentage of ampicillin-, nalidixic acid- or ciprofloxacin-resistant strains has almost doubled in the follow-up period, from 56 to 76% for ampicillin- and from 47.5 to 88% for quinolone-resistant strains. This study clearly shows that a mutation in Thr-86 to Ile or Lys is a frequent mechanism associated with the acquisition of a high level of resistance to quinolones in clinical isolates of C. jejuni.

Anti-Infective Agents↗
PubMed1998

Prevalence of diarrheagenic Escherichia coli strains detected by PCR in patients with travelers' diarrhea.

OBJECTIVE: To determine the prevalence of the different categories of diarrheagenic Escherichia coli, enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), verotoxin-producing E. coli (VTEC), enteroaggregative E. coli (EAggEC), diffusely adherent E. coli (DAEC), and enteropathogenic E. coli (EPEC), associated with travelers' diarrhea. METHODS: Stool specimens from 350 patients with travelers' diarrhea were collected between 1994 and 1996. The virulence factors of the diarrheagenic E. coli isolated were detected by PCR technique, in subcultures of single colonies of all morphotypes of E. coli observed in culture on MacConkey agar. RESULTS: ETEC (15.7%), EAggEC (13.4%) and DAEC (9.14%) are significantly more prevalent than EIEC (3.4%), EPEC (2.86%) and VTEC (0.86%) (p<0.05; z-test). The prevalence of ETEC and EAggEC was similar in all geographic areas visited. CONCLUSIONS: PCR is a rapid and specific technique to use in the identification of the different categories of diarrheagenic E. coli and greatly increases the yield of potential enteropathogens from cases of travelers' diarrhea. Not only ETEC but also EAggEC and DAEC strains play a major role in the etiology of travelers' diarrhea, whereas EIEC, EPEC, and VTEC strains play a minor role, leading to the question of whether it is necessary to search routinely for these three types of E. coli in diagnostic laboratories.

Journal Article↗
PubMed1998

Campylobacter jejuni as a cause of traveler's diarrhea: clinical features and antimicrobial susceptibility.

Traveler's diarrhea is the most common health problem of international travelers. Although enterotoxigenic Escherichia coli seems to be the most frequent cause of traveler's diarrhea, many other microorganisms, such as Campylobacter jejuni, may cause this infectious disease. Campylobacter jejuni is recognized as a leading cause of enteritis in humans both in developing and in developed countries. However, a few reports on the incidence and antimicrobial resistance of Campylobacter spp. as a cause of traveler's diarrhea have been published. The limited data on the treatment of C. jejuni infections suggest that ciprofloxacin may shorten the duration of symptoms. However, treatment failure associated with the emergence of quinolone-resistant strains of C. jejuni has been documented. The purpose of this study was to determine the prevalence of C. jejuni associated with traveler's diarrhea and to analyze the geographic distribution as well as the clinical features and susceptibility to antibiotics.

Anti-Bacterial Agents↗
PubMed1997

Isolation of verotoxin-producing Escherichia coli O-rough:K1:H7 from two patients with traveler's diarrhea.

Two Escherichia coli O-rough:K1:H7 strains producing verotoxin 1 that were isolated from stool samples of two travelers with diarrhea who consulted our clinic after trips to the Indian Subcontinent and Central America were characterized. Both strains were sorbitol negative, the same phenotype presented by E. coli O157:H7, but in contrast they were beta-glucuronidase positive. Low-frequency restriction analysis of chromosomal DNA and pulsed-field gel electrophoresis and repetitive extragenic palindrome-PCR showed that both strains were epidemiologically related. The illness was self-limited in both cases but involved long-duration, watery diarrhea (10 to 50 days) accompanied by abdominal cramps and flatulence. This serotype should be taken into account as a possible cause of traveler's diarrhea.

Adult↗
PubMed1996

[Increase of myocardial perfusion during antilipemic treatment in patients with ischemic cardiopathy].

OBJECTIVES: To evaluate if cholesterol lowering therapy with simvastatin increases myocardial perfusion, assessed by Thallium-201 single photon emission computed tomography (SPECT) after dipyridamole, in patients with coronary artery disease. PATIENTS AND METHODS: Ten hypercholesterolemic subjects with coronary artery disease were selected for a pilot study. Lipid and lipoprotein analysis and Thallium-201 SPECT were performed before and after 16 weeks of treatment with 40 mg of simvastatin QD. SPECT images were qualitatively analyzed in 8 myocardial segments using a 4 point scoring system. Quantitative evaluation was performed in 13 segments. The myocardial region with the maximal mean counts per pixel on the stress study was considered the reference region. TI201 activity in all other myocardial regions was expressed as a percentage of the activity in the reference region. RESULTS: Total cholesterol and LDL cholesterol were reduced by 28.4% and 37.1% with treatment. Global myocardial perfusion was increased in all patients. Qualitative analysis demonstrated that cholesterol lowering improved myocardial perfusion during dipyridamole stress. Quantitative analysis showed an increased global perfusion during stress (41.8% vs 54.6%; p < 0.0001), due to increased perfusion of previous ischemic segments (32.4% vs 49.4%; p < 0.0001) but without changes in previous normally perfused segments (71.5% vs 71.3%). CONCLUSION: Reduction of cholesterol levels in hypercholesterolemic subjects with coronary artery disease increases myocardial perfusion in ischemic segments during dipyridamole stress test as assessed by single photon emission computed tomography (SPECT).

Adult↗
PubMed1995

Expression of ferredoxin-dependent glutamate synthase in dark-grown pine seedlings.

Pine seedlings are able to accumulate chlorophylls and develop green plastids in a light-independent manner. In this work, we have characterized ferredoxin-dependent glutamate synthase (EC 1.4.7.1; Fd-GOGAT), a key enzyme in nitrogen interconversion during this process. Fd-GOGAT has been purified about 170-fold from cotyledons of maritime pine (Pinus pinaster). As occurs in angiosperms, the native enzyme is a single polypeptide with an apparent molecular mass of 163-168 kDa that is confined to the chloroplast stroma. Polyclonal antibodies generated against the purified enzyme were used to immunoscreen a lambda gt11 expression library from Scots pine (Pinus sylvestris) seedlings and partial cDNA clones were isolated and characterized. The clone with the longest cDNA insert (pGOP44) contained the codification for the C-terminal (550 amino acids) of the pine Fd-GOGAT polypeptide. Immunological cross-reactivity and comparative amino sequence analysis revealed that Fd-GOGAT is a well conserved protein in higher plants. Western blot analyses showed that protein was expressed in chloroplast-containing pine tissues and this expression pattern was not affected by exogenously supplied nitrogen. Fd-GOGAT mRNA, polypeptide and enzyme activity accumulated in substantial amounts in dark-grown pine seedlings. The presence of a functional Fd-GOGAT may be important to provide the required glutamate for the biosynthesis of nitrogen compounds during chloroplast biogenesis in the dark.

Amino Acid Oxidoreductases↗
PubMed1995

Monocotyledonous C4 NADP(+)-malate dehydrogenase is efficiently synthesized, targeted to chloroplasts and processed to an active form in transgenic plants of the C3 dicotyledon tobacco.

Chloroplastic NADP(+)-malate dehydrogenase (cpMDH, EC 1.1.1.82) is a key enzyme in the carbon-fixation pathway of some C4 plants such as the monocotyledons maize or Sorghum. We have expressed cpMDH from Sorghum vulgare Pers. in transgenic tobacco (Nicotiana tabacum L.) (a dicotyledonous C3 plant) by using a gene composed of the Sorghum cpMDH cDNA under the control of cauliflower mosaic virus 35S promoter. High steady-state levels of cpMDH mRNA were observed in isogenic dihaploid transgenic tobacco lines. Sorghum cpMDH protein was detected in transgenic leaf extracts, where a threefold higher cpMDH activity could be measured, compared with control tobacco leaves. The recombinant protein was identical in molecular mass and in N-terminal sequence to Sorghum cpMDH. The tobacco cpMDH protein which has a distinct N-terminal sequence, could not be detected in transgenic plants. Immunocytochemical analyses showed that Sorghum cpMDH was specifically localized in transgenic tobacco chloroplasts. These data indicate that Sorghum cpMDH preprotein was efficiently synthesized, transported into and processed in tobacco chloroplasts. Thus, C3-C4 photosynthesis specialization or monocotyledon-dicotyledon evolution did not affect the chloroplastic protein-import machinery. The higher levels of cpMDH in transgenic leaves resulted in an increase of L-malate content, suggesting that carbon metabolism was altered by the expression of the Sorghum enzyme.

Amino Acid Sequence↗
PubMed1995

Colchicine in the treatment of cutaneous leukocytoclastic vasculitis. Results of a prospective, randomized controlled trial.

BACKGROUND AND DESIGN: Cutaneous leukocytoclastic vasculitis is an inflammatory vascular disease with a variable course. There is no defined therapy for this entity. Contradictory data on the effect of colchicine have been reported. To determine the efficacy of colchicine in cutaneous leukocytoclastic vasculitis, 41 patients were randomly selected to receive oral colchicine, 0.5 mg twice daily, or topical emollients. Response to treatment was judged according to the reduction in the number of lesions. After 1 month, in those patients in whom a complete or no response was achieved, therapy was withdrawn; in those with a partial response, treatment was maintained for the following 2 months. At the end of 3 months, treatment was continued only in those patients in whom a relapse occurred. RESULTS: Twenty patients in each group completed 1 month of treatment. One patient taking colchicine dropped out because of diarrhea. At the end of the first month of the study, five patients in the control group and four in the colchicine group achieved a complete response. Nine patients who had a partial response (four in the colchicine group and five in the control group) continued to receive treatment for the following 2 months. Three patients in the colchicine group suffered a relapse after discontinuing therapy but experienced remission with reinstitution of therapy. At the end of the 3 month period, 12 patients in the colchicine group and 10 patients in the control group showed no significant response. Complete response was achieved in five patients in the colchicine group and in seven in the control group. At the 1-year follow-up, 10 patients in each group had no clinical evidence of cutaneous vasculitis. CONCLUSIONS: Colchicine had no significant therapeutic effect in this controlled study. However, the finding that relapse occurred on cessation of colchicine therapy in three complete responders suggests that colchicine can be effective in some patients, despite our negative results.

Administration, Cutaneous↗
PubMed1994

Radionuclide assessment of right ventricular contractile reserve after acute myocardial infarction.

Conflicting data have been reported about the implications of a decreased right ventricular (RV) contractile reserve (i.e., a < 5% stress-induced increase in ejection fraction [EF]). If a reduced reserve corresponds to ischemia, it will probably be associated with an electrocardiographic marker of RV ischemia, stress-induced ST-segment elevation (increases ST) in leads V3R to V6R. To test this hypothesis, 98 asymptomatic postinfarction patients (27 with RV infarction) were assigned to a dobutamine stress test (maximal dose 40 micrograms/kg/min) with equilibrium radionuclide angiography and electrocardiographic study, including leads V3R to V6R. All but 11 patients underwent coronary angiography. A dobutamine-induced increases ST in VR leads was seen in 24 patients with and in 8 without RV infarction. This electrocardiographic sign was 75% sensitive and 84% specific for the diagnosis of proximal right coronary artery disease. It was 61% sensitive and 74% specific for the detection of reduced RV contractile reserve. Patients with RV infarction had reduced RVEF at rest (38 +/- 9%), but the mean contractile reserve was normal (12 +/- 12%). The contractile reserve was significantly smaller in patients with proximal versus distal or no right coronary artery disease. It was also smaller (P < 0.01) in patients with increased ST versus no increased ST. In conclusion, high doses of dobutamine are useful in assessing RV contractile reserve after acute myocardial infarction. In these patients, a reduced RV contractile reserve is related to proximal right coronary artery disease and is associated with stress-induced increased ST in VR leads.

Adult↗
PubMed1994

Oral midazolam as premedication for the apprehensive child before dental treatment.

A double-blind study was undertaken to determine the efficacy of an oral dose of midazolam 7.5 mg as compared to placebo in a sample of 32 children who had refused dental care after the conventional psychological approach alone was used to reduce fear and apprehensive behavior. Parameters assessed before and 30 minutes after the oral administration of either midazolam or placebo were mental attitude, hypnotic activity, motor activity, quality of sedation and of dental treatment. A three-point scale was designed in each studied parameter and mean values +/- s.e.m. were compared before and after treatment by using Wilcoxon's rank test. It was shown that an oral dose of midazolam 7.5 mg significantly improved all parameters under evaluation (p < 0.01) as compared to placebo, effects which appeared thirty minutes after administration. It is concluded that oral midazolam provides a fast and adequate sedation in children refusing dental care. Thus, the drug is an alternative to other sedative or hypnotic drugs currently used in the premedication of the apprehensive child.

Anesthesia, Dental↗
PubMed1993

Molecular characterization of a cDNA clone encoding glutamine synthetase from a gymnosperm, Pinus sylvestris.

A full-length cDNA clone (pGSP114) encoding glutamine synthetase was isolated from a lambda gt11 library of the gymnosperm Pinus sylvestris. Nucleotide sequence analysis showed that pGSP114 contains an open reading frame encoding a protein of 357 amino acid residues with a calculated molecular mass of 39.5 kDa. The derived amino acid sequence was more homologous to cytosolic (GS1) (78-82%) than to chloroplastic (GS2) (71-75%) glutamine synthetase in angiosperms. The lack of N-terminal presequence and C-terminal extension which define the primary structure of GS2, also supports that the isolated cDNA encodes cytosolic GS. Southern blot analysis of genomic DNA from P. sylvestris and P. pinaster suggests that GS may be encoded by a small gene family in pine. GS mRNA was more abundant in cotyledons and stems than in roots of both Scots and maritime pines. Western blot analysis in P. sylvestris seedlings showed that only one GS polypeptide, similar in size to GS1 in P. pinaster, could be detected in several different tissues. Our results suggest that cytosolic GS is mainly responsible for glutamine biosynthesis in pine seedlings.

Amino Acid Sequence↗
PubMed1992

Effects of sodium meclofenamate on postoperative pain following periodontal surgery.

The analgesic activity of single doses of meclofenamate (100 mg) was compared to aspirin (500 mg) and to placebo on 99 outpatients with moderate to severe pain following periodontal surgery under double-blind conditions. Pain intensity differences scores (PID) at the first, second, and third hour after the ingestion of the first capsule of each medication were used to determine the analgesic efficacy of the studied drugs. Kruskal Wallis test followed by the Mann-Whitney rank sum test were used in the statistical analysis of results. Meclofenamate was statistically superior to placebo and superior to aspirin in the second hour of evaluation, while aspirin was not superior to placebo during the 3-hour period of pain evaluation. It is concluded that meclofenamate is a non-steroidal antiinflammatory drug with interesting analgesic properties which can be used as directed as an alternative to aspirin or acetaminophen for the control of postoperative pain following periodontal surgery.

Adult↗
PubMed1990

Analgesic and antiinflammatory effects of glucamethacin (a nonsteroidal antiinflammatory analgesic) after the removal of impacted third molars.

A double-blind study was undertaken to compare the effects of glucamethacin, aspirin, and placebo in the control of pain, trismus, and postoperative swelling of 59 outpatients who underwent the surgical removal of impacted lower third molars. Aspirin (1000 mg three times a day) was superior to placebo in one of the analgesic parameters studied, whereas glucamethacin (140 mg three times a day) was not superior to placebo. Both drugs significantly reduced the occurrence of trismus on the day after surgery, but no differences with placebo were found 48 hours postoperatively. In the study of postoperative swelling, no significant differences were found between the medications and the placebo in the postoperative period. It is concluded that glucamethacin, a nonsteroidal antiinflammatory drug, produces a minimal analgesic effect and does not relieve postoperative swelling in the dental patient undergoing surgical removal of impacted third molars.

Adolescent↗
PubMed1990

Analgesic efficacy of flurbiprofen as compared to acetaminophen and placebo after periodontal surgery.

The purpose of the present investigation was to compare the analgesic efficacy of flurbiprofen, a nonsteroidal anti-inflammatory drug, which is a phenyl propionic acid derivative, with acetaminophen and placebo in 63 adult outpatients with moderate to severe dental pain following periodontal surgery. After surgery was completed under local anesthesia, the patients received under double-blind conditions an envelope containing four tablets of either flurbiprofen 100 mg, acetaminophen 500 mg, or placebo and they were instructed to take one tablet every 6 hours when postoperative pain reached moderate to severe intensity. To determine analgesic efficacy and patients recorded pain intensity on a scale of 0 to 3. Patients were allowed to remedicate after 1 hour if pain was not reduced. Flurbiprofen was shown to possess an adequate analgesic effect superior to either placebo (P less than 0.005) or acetaminophen (P less than 0.01) in the parameters studied. Our results seem to further support earlier data obtained with the drug in dental patients with postoperative pain after the surgical removal of impacted third molars; therefore, it is concluded that flurbiprofen used as directed is a new alternative for the proper treatment of pain following periodontal surgery.

Acetaminophen↗