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M Segura

Publications and source records attributed to M Segura.

At least 37 records · Page 2Linked to original sources
PubMed1996

A clinical trial on the prevention of catheter-related sepsis using a new hub model.

BACKGROUND: Catheter hub contamination is being increasingly recognized as a source of catheter-related sepsis. The authors have investigated the efficacy of a new hub design in preventing endoluminal catheter contamination and catheter-related sepsis arising at the hub. METHODS: Adult surgical and intensive care patients requiring a subclavian catheter for at least 1 week were randomly assigned to receive catheters with standard connectors (control group, n=73) or equipped with a new hub model (new hub group, n=78). Skin, catheter tip, and hub cultures were performed at the time the catheter was withdrawn because therapy was terminated or because of suspicion of sepsis, in which case peripheral blood cultures were taken. RESULTS: Of the 151 patients included, 15 (10%) developed catheter-related sepsis. Catheters were more often withdrawn because suspicion of infection in the control group (42 vs. 19%, p<0.005). Catheter sepsis rate was higher in the control group (16 vs. 4%, p<0.01) because of the low rate of catheter sepsis arising at the hub observed in the new hub group (1 vs. 11%, p<0.01). The prevalence of culture-positive catheter hubs without associated bacteremia (colonization) was higher in the control group (18 vs. 5%, P<0.03). CONCLUSIONS: A new catheter hub has proved to be useful in preventing endoluminal bacterial colonization and catheter-related sepsis in subclavian lines inserted for a mean of 2 weeks.

Adult↗
PubMed1995

Pathogenesis and prevention of catheter-related septicemia.

Intravascular catheters are contaminated by bacterial flora present on the patient's own skin or on the hands of the personnel manipulating the catheter-tubing junction. In the former case, contamination is more often extraluminal and often leads to CRS soon after catheter insertion. In the second circumstance, contamination preferentially involves the endoluminal route and results in bacteremia after the initial 10 to 14 days of catheter use. Effective prevention relies on thorough aseptic technique during insertion of the catheter or manipulation of its hub. Further studies are required to define the best means of achieving permanent sterilization of the insertion site. New hub designs should reduce the risk of hub contamination and CRS in prolonged intravascular catheterizations.

Bacteremia↗
PubMed1995

[Hemichorea associated with cerebral toxoplasmosis and AIDS].

Only 12 AIDS cases with hemichorea were reported in the literature. We report the first case of hemichorea associated with AIDS and cerebral toxoplasmosis in our country. A 26-year-old man had 3 episodes of focal seizures on the left side with subsequent loss of consciousness. A few weeks later, he noticed progressive left-sided weakness. Examination revealed a left hemiparesis. MRI of the head showed a round mass in the right frontal lobe and a smaller lesion in the left temporo-occipital area. Laboratory showed positive serum ELISA and Western Blot analysis for HIV antibodies. Serum tests for Toxoplasma showed elevated titers. He was treated with pyrimethamine and sulfadiazine. His weakness improved and he had no further seizures. Two weeks later, choreic movements appeared in the left foot, finally involving the entire left hemibody. A second MRI showed a new small lesion in the right cerebral peduncle. The patient completed 6 weeks of treatment, with further reduction in the size of the lesions. Nevertheless, the left hemichorea persisted. We believe that the hemichorea our patient had was caused by the contralateral peduncular lesion. Lesions involving the subthalamic nucleus or its connections may cause contralateral hemiballismus or hemichorea. In spite of the favorable response to antitoxoplasmic therapy, the hemichorea persisted. The present report illustrates an uncommon neurological complication in AIDS. We believe that a combination of a focal cerebral lesion and the HIV infection caused the movement disorder presented by the patient.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Cognitive impairment in human chronic Chagas' disease.

UNLABELLED: We proposed to investigate subclinical cognitive impairment secondary to chronic Chagas' disease (CCD). No similar study was previously done. The neuropsychological performance of 45 chronic Chagasic patients and 26 matched controls (age, education place and years of residency in endemic area) was compared using the Mini Mental State Exam (MMSE), Weschler Memory Scale (WMS) and the Weschler Adult Intelligent Scale (WAIS). Non-parametric tests and Chi2 were used to compare group means and multivariate statistics in two way frequency tables for measures of independence and association of categorical variables with the disease. RESULTS: Chagasic patients showed lower MMSE scores (p < .004), poor orientation (p < .004), and attention (p < .007). Lower WMS MQ were associated with CCD (Chi2 5.9; p < .01; Fisher test p < .02). Lower WAIS IQ were associated with CCD (Chi2 6.3, p < .01; Fisher test p < .01) being the digit symbol (p < .03), picture completion (p < .03), picture arrangement (p < .01) and object assembly (p < .03) subtests the most affected. The impairment in non-verbal reasoning, speed of information processing, problem solving, learning and sequencing observed in chronic Chagas disease patients resembles the cognitive dysfunction associated with white matter disease.

Adult↗
PubMed1993

A prospective study of a new protocol for 'in situ' diagnosis of central venous catheter related bacteraemia.

59 patients with suspected central venous catheter related bacteraemia (CRB), while receiving parenteral nutrition, were studied prospectively. 41 (Group 1) were managed conservatively: cultures were taken from the catheter hub lumen, skin at the catheter entry site and peripheral blood; the catheter was then heparinised and locked for 24-48 h. The catheter was withdrawn only if cultures were positive; otherwise parenteral nutrition was resumed. In 18 patients the catheter was immediately withdrawn (Group 2) and the same cultures plus tip culture were performed. 13 patients of Group 1 with positive hub or skin cultures, had their catheters removed and 12 had blood cultures matching for the same micro-organism. Negative skin and hub cultures had a negative predictive value for CRB of 96%. A positive hub culture had a 100% positive predictive value for CRB. CRB was diagnosed in 11 patients out of the 18 in whom catheters were withdrawn immediately (Group 2). Thus, 1 out of 41 catheters and 7 out of 18 catheters were removed unnecessarily in Groups 1 and 2 respectively (p = 0.001, Fisher's test). In all, 24 CRBs were documented and 15 were due to coagulase negative staphylococci. The catheter hub was the commonest origin of CRB followed by the infusate and the skin. In febrile patients on parenteral nutrition, negative skin and hub cultures accurately predict or rule out CRB and should be used more often to avoid withdrawal of sterile catheters.

Journal Article↗
PubMed1991

Peptidyl-tRNA hydrolase is involved in lambda inhibition of host protein synthesis.

Escherichia coli rap mutants do not support vegetative growth of bacteriophage lambda and die upon transcription of lambda DNA bar sites. Bacteria harbouring a pth(ts) mutation synthesize thermosensitive peptidyl-tRNA hydrolase (Pth) and die at 42 degrees C from a defect in protein synthesis. We present evidence that both rap and pth(ts) mutations affect the same gene: (i) peptidyl-tRNA hydrolase activity was found to be defective in rap mutants; (ii) at a threshold temperature, pth cells, like rap mutants, prevented lambda growth and were killed by transcription of cloned bar sites; (iii) sequencing a 1600 bp DNA fragment comprising both loci revealed an ORF located within the limits set by a complementation analysis and encoding a putative polypeptide of 21 kDa; (iv) cloning and sequencing of rap and pth(ts) mutant DNAs both revealed single nucleotide transitions from the wild type ORF sequence, resulting in Arg134 to His and Gly101 to Asp changes respectively. Analysis of plasmid-directed proteins identified a polypeptide of approximately 21 kDa; the N-terminal sequence, amino acid composition and isoelectric point of this protein match those expected from the ORF nucleotide sequence. We propose that Pth activity, directly or indirectly, is the target for lambda bar RNA leading to rap cell death.

Bacteriophage lambda↗
PubMed1990

Assessment of a new hub design and the semiquantitative catheter culture method using an in vivo experimental model of catheter sepsis.

An in vivo model of hub-related catheter sepsis in rabbits is reported. The model was used to investigate the protection offered by a new hub design against external contamination by Pseudomonas aeruginosa or Staphylococcus epidermidis and to reassess the diagnostic value of the semiquantitative culture method in bacteremia of endoluminal origin. Contamination of conventional Luer-Lock connectors was followed by clinical sepsis, positive catheter segment cultures, or both, whereas contamination of the new hub was followed by complete protection. Clinical and bacteriological discrepancies observed between contamination with P. aeruginosa and S. epidermidis suggest that the virulence of microorganisms may account for differences in the natural history of hub-originated catheter sepsis. The semiquantitative extraluminal method for catheter culture yielded less than 15 CFU in three animals with proven bacteremia and should not be used as the "gold standard" to define catheter-related bacteremia.

Animals↗
PubMed1989

Measurement of body water compartments after ligation of the common bile duct in the rabbit.

To elucidate the pathogenesis of renal insufficiency associated with obstructive jaundice we have studied spontaneous water intake and body water compartments in rabbits undergoing common bile duct ligation. Total body water, extracellular water and plasma volume were measured by multi-isotope dilution technique. During the initial 6 postoperative days spontaneous water intake was 898 ml in sham operated animals (SO) but only 280 ml in jaundiced rabbits (OJ6) (P less than 0.01). Creatinine clearance was almost unchanged in SO but fell to 60 per cent of the preoperative values both in OJ6 and in paired-drink sham operated animals (SO2). There was a 15 per cent decrease in total body water (P less than 0.01) and a 24 per cent decrease in extracellular water (P less than 0.01) 6 days after bile duct ligation. There was a further reduction of the extracellular water to 35 per cent and a 15 per cent reduction of plasma volume 12 days after ligation. Water restriction mimicked the alterations in body composition produced by bile duct ligation. We conclude that bile duct ligation is associated with hypodypsia and a depletion of extracellular water and plasma volume. These alterations could explain the tendency to develop hypotension and renal failure which are associated with obstructive jaundice.

Animals↗
PubMed1989

Treatment of 27 postoperative enterocutaneous fistulas with the long half-life somatostatin analogue SMS 201-995.

Twenty-seven patients with postoperative enterocutaneous fistulas were treated with parenteral nutrition and SMS 201-995 (100 micrograms/8 hours, subcutaneously), a long half-life somatostatin analogue. At the time SMS 201-995 was started, 11 patients had low output fistulas (less than 1000 ml/48 hours), 11 patients had high output fistulas (above 1000 ml/48 hours), and 5 patients had fistulas sitting in large abdominal wall defects. Within 24 hours of treatment, a mean reduction of 55% of the fistula output was observed. Fistula site or output before treatment had no influence on the magnitude of output reduction. Spontaneous closure was achieved in 77% of the patients after a mean of 5.8 +/- 2.7 days of treatment with this drug. Two patients died (7.4%). Pain at the injection site was referred by 15% of the patients but no other side effects were observed. Glucose intolerance was not observed. SMS 201-995 has been shown to be very useful in the conservative treatment of enterocutaneous fistulas because of its ability to rapidly reduce fistula output and accelerate spontaneous closure.

Adult↗
PubMed1989

In vitro bacteriological study of a new hub model for intravascular catheters and infusion equipment.

We investigated in vitro the antibacterial properties of a simulated new hub model in which the female part has an antiseptic chamber through which the needle (male part) must pass before connection of the set and the catheter. To establish the time needed for disinfection, the magnitude of reduction of the contaminating inocula by the new hub model, and the antibacterial properties of the different components of the hub, we used needles contaminated with solutions containing high inocula (1.9 x 10(7) to 1.2 x 10(11) CFU/ml) of microorganisms involved in hub-related catheter sepsis. Sterilization of the needles was accomplished by allowing them to remain in the antiseptic chamber for 10 s in all assays with Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. The rubber closures limiting the antiseptic chamber and the dilution effect of the antiseptic itself accounted for a minor part of the inoculum reduction achieved by the new hub model. This simulated hub provides good protection against endoluminal contamination. Further studies seem warranted to prove its industrial viability and clinical efficacy.

Candida albicans↗
PubMed1988

Determination of the Processing Sites of an Arabidopsis 2S Albumin and Characterization of the Complete Gene Family.

The most abundant isoform of the 2S albumin present in seeds of Arabidopsis thaliana has been sequenced and the corresponding gene isolated. Examination of the protein and DNA sequences allows the determination of the exact proteolytic cleavage sites during posttranslational processing. Like other 2S albumins, that of Arabidopsis is made as a prepropeptide. After removal of the signal peptide, the propeptide is cleaved at four other points, giving two subunits linked by a disulfide bridge(s). Comparison of these cleavage sites with those of 2S albumins of Brassica napus and Bertholletia excelsa suggests that while individual cleavage sites between species are conserved, the four processing sites within a species are not similar, suggesting that up to four different proteases may be involved in processing 2S albumins. The Arabidopsis 2S albumin gene was used to isolate the entire gene family. There are four genes, tightly linked in a tandem array. None of the genes contains an intron. Comparison of the predicted protein sequences shows that only one of the genes can encode the isoform determined by protein analysis to be the most abundant, and therefore this gene is certain to be expressed. It is possible that some or all of the other three genes are also active.

Journal Article↗
PubMed1987

Blind evaluation of the effect of octreotide (SMS 201-995), a somatostatin analogue, on small-bowel fistula output.

In a blind crossover trial for 4 days, after at least 7 days on conventional treatment, 14 patients with postoperative small-bowel fistula were randomised to 2 days on a somatostatin analogue, octreotide (SMS 201-995), followed by 2 days on placebo (group 1) or vice versa (group 2), after which all patients were treated with octreotide until the fistula closed or reoperation was deemed necessary. In group 2 mean fistula output was reduced from 698 ml per 24 h pretreatment to 246 mg per 24 h after 2 days on octreotide; output increased from 228 ml per 24 h to 497 ml per 24 h when treatment with octreotide was interrupted by placebo. In 11 patients fistulae closed spontaneously in an average of 4.5 days after continous treatment with octreotide.

Adult↗
PubMed1984

Separation of non-muscle isoactins in the free form or as profilactin complexes.

Profilactin prepared from calf spleen by the standard procedure (Carlsson, L., Nyström, L.-E., Sundkvist, I., Markey, F., and Lindberg, U. (1977) J. Mol. Biol. 115, 465-483) can be further fractionated by chromatography on hydroxyapatite into two major peaks; one containing profilin in combination with gamma-actin (PA gamma) and the other combined with beta-actin (PA beta). Both complexes were shown to consist of 1 mol each of the two proteins. The two forms of profilin, PI (intact form) and PII (lacking the COOH-terminal glutamine and tyrosine residues) (Malm, B., Larsson, H., and Lindberg, U. (1983) J. Muscle Res. Cell Motil. 4, 569-588), were found unequally distributed between the two major peaks of PA, such that PA gamma contained mainly PI and PA beta both PI and PII. The significance of this finding remains unclear. Isoelectrofocusing showed that PI from both isoforms of PA had an isoelectric point of 9.08. Profilin II gave rise to two major bands on isoelectrofocusing having isoelectric points of 9.12 and 9.18, respectively. Finally it was shown that the two isoforms of actin can be separated from each other in the absence of profilin also by chromatography on hydroxyapatite. In this case, ATP remains bound to the actins eluted from the chromatographic matrix and both actins were shown to polymerize on addition of salts as judged by viscometry.

Actins↗
PubMed1982

Separation of the mRNAs coding for different forms of chick embryo gizzard tropomyosin.

The fractionation of gizzard tropomyosin from 17-day-old chick embryos by electrophoresis in polyacrylamide gels indicates that this protein is composed of three different polypeptides that were designated as alpha, beta, and gamma. Each one of these polypeptides is resolved into two components with different isoelectric points when tropomyosin is fractionated by two-dimensional electrophoresis; the major components were designated as tropomyosins alpha 1, beta 1, and gamma 1 and the minor ones as tropomyosins alpha 2, beta 2, and gamma 2. The results of in vitro translation of gizzard RNA indicate that only tropomyosins alpha 1, beta 1, and gamma 1 are synthesized in the cell-free system. A partial separation of the mRNAs coding for tropomyosins alpha 1 and gamma 1 was obtained by fractionation of gizzard RNA by zonal centrifugation in sucrose gradients. Altogether these results indicate that in gizzard tissue from 17-day-old chick embryos three genes coding for different forms of tropomyosin are expressed.

Animals↗
PubMed1982

Phosphorylated and unphosphorylated forms of cardiac tropomyosin.

Cardiac tropomyosin from 20-day-old chick embryos is composed of three different polypeptides with the same molecular weight but different isoelectric points. These polypeptides, which are designated as alpha 1, alpha 2, and alpha 3, have identical peptide maps. In vitro, however, only polypeptide alpha 1 is synthesized in a reticulocyte lysate programmed with cardiac RNA. These results, together with the observations indicating that tropomyosin alpha 2 corresponds to a phosphorylated polypeptide, suggest that only tropomyosin alpha 1 corresponds to a primary translational product and that forms alpha 2 and alpha 3 are derived from alpha 1 as a consequence of posttranslational modifications.

Animals↗
PubMed1979

Differential expression of gizzard actin genes during chick embryogenesis.

The iso forms of gizzard actin present during chicken embryogenesis were analyzed by two-dimensional electrophoresis. During chick embryogenesis there are conspicuous changes in the content of the iso forms of actin. Gizzards from 8-day-old embryos contain almost exclusively beta-actin. After 8 days of embryonic age, there is a continuous increase in the amount of gamma-actin and an apparent decrease in the amount of beta-actin. These changes in the content of beta- and gamma-actin in gizzard tissue are paralleled by changes in the content of the corresponding mRNAs, as detected by the ability of the RNAs to direct the synthesis of these proteins in micrococcal nuclease-digested reticulocyte lysates. The correlation of the in vivo and in vitro experiments indicates that during chick embryogenesis there is a differential expression of the genes coding for the iso forms of gizzard actin and that this expression is controlled at the transcriptional level.

Actins↗