PubMed Health⌕ Search

Biomedical subjects

E Garduño

Publications and source records attributed to E Garduño.

14 recordsLinked to original sources
PubMed2005

Exposure to therapeutic concentrations of ritonavir, but not saquinavir, reduces secreted aspartyl proteinase of Candida parapsilosis.

The effect of ritonavir and saquinavir, HIV proteinase inhibitors, on the secreted aspartyl proteinase (Sap) activity of Candida parapsilosis was studied. In a proteinase-inducing medium (yeast carbon base-bovine serum albumin), Sap activity in all clinical isolates of C. parapsilosis (n = 20) was observed at 37 degrees C but not at 22 degrees C. The presence of ritonavir at a concentration of 8 microg/ml produced an inhibition close to 50% albumin consumption and also delayed yeast growth; however, saquinavir did not have any effect on growth or on Sap activity. In Sabouraud broth, which does not induce Sap production, no effect was shown on yeast growth by either of the two HIV proteinase inhibitors studied.

Aspartic Acid Endopeptidases↗
PubMed2001

The content of glycogen phosphorylase and glycogen in preparations of sarcoplasmic reticulum-glycogenolytic complex is enhanced in diabetic rat skeletal muscle.

AIMS/HYPOTHESIS: We have examined the effect of diabetes and pharmacological insulin treatment on the content of glycogen phosphorylase and glycogen associated with the sarcoplasmic reticulum-glycogenolytic complex from rat skeletal muscle. METHODS: Diabetes was induced in rats by streptozotocin injection. Enzymatic activities were measured using spectrophotometric methods. Glycogen phosphorylase was determined measuring the pyridoxal-5' -phosphate content and using polyacrylamide gel electrophoresis. Glycogen content was measured by enzymatic and the phenol sulfuric methods. RESULTS: The content of glycogen phosphorylase associated with the sarcoplasmic reticulum glycogenolytic complex gradually arises after diabetes induction. The content of glycogen phosphorylase was restored to a control value by pharmacological insulin treatment. In addition, the content of glycogen in preparations of sarcoplasmic reticulum-glycogenolytic complex of diabetic animals was also increased, whereas the content of glycogen in total muscle of diabetic rats was similar to that of the control rats. The absolute and relative amount of glycogen associated with sarcoplasmic reticulum seemed to increase in diabetic animals. These effects on the compartmentalisation of glycogen were suppressed by insulin treatment. Additionally, the rate of conversion of glycogen phosphorylase b to a, an index of the phosphorylase kinase activity, was 50 % lower in diabetic rats, increasing the dephosphorylated form of glycogen phosphorylase and, as a consequence, its association with sarcoplasmic reticulum membranes. CONCLUSION/INTERPRETATION: These results suggest that under diabetic conditions, both glycogen phosphorylase and a small percentage of muscle glycogen are relocalized in the sarcoplasmic reticulum-glycogenolytic complex.

Animals↗
PubMed2000

Splenic abscesses caused by Actinomyces meyeri in a patient with autoimmune hepatitis.

We report a case of actinomycosis with uncommon localizations that was due to Actinomyces meyeri. Although penicillin is the standard treatment for this condition, our patient was treated successfully with imipenem. Actinomyces organisms are important constituents of the normal flora of mucous membranes and are considered opportunistic pathogens; these organisms may produce infection after local trauma, surgery, or aspiration. The mains forms of actinomycosis are cervicofacial, thoracic, and abdominal; most cases are due to Actinomyces israelii, whereas other Actinomyces species are occasionally implicated. Actinomycosis usually occurs in immunocompetent persons, but may occur in persons with diminished host defenses.

Abdominal Abscess↗
PubMed2000

Co-culture of Aeromonas salmonicida and host cells in intraperitoneal implants is associated with enhanced bacterial survival.

An experimental procedure that we named "in vivo co-culture technology" allowed us to study the interactions between Aeromonas salmonicida and host cells, inside semipermeable chambers implanted in the peritoneal cavity of Atlantic salmon. Intraperitoneal implants containing bacteria and host cells, or bacteria and lysed cells, consistently yielded higher numbers of viable bacteria than implants containing bacteria only. Electron microscopy confirmed that 30 min after chamber inoculation, numerous bacteria were already internalized by exudate cells, and that at 3 h, destruction of these cells was evident. Thus, the rapid invasion and (or) the A. salmonicida-mediated lysis of host cells may constitute a survival strategy in vivo. The co-culture of bacteria with exudate peritoneal cells may be applicable to the in vivo study of other pathogens.

Aeromonas↗
PubMed2000

Host cell invasion and intracellular residence by Aeromonas salmonicida: role of the S-layer.

Virulent strains of the fish pathogen Aeromonas salmonicida, which have surface S-layers (S+), efficiently adhere to, enter, and survive within macrophages. Here we report that S+ bacteria were 10- to 20-fold more adherent to non-phagocytic fish cell lines than S-layer-negative (S-) mutants. When reconstituted with exogenous S-layers, these S- mutants regained adherence. As well, latex beads coated with purified S-layers were more adherent to fish cell lines than uncoated beads, or beads coated with disorganized S-layers, suggesting that purified S-layers were sufficient to mediate high levels of adherence, and that this process relied on S-layer structure. Gentamicin protection assays and electron microscopy indicated that both S+ and S- A. salmonicida invaded non-phagocytic fish cells. In addition, these fish cells were unable to internalize S-layer-coated beads, clearly suggesting that the S-layer is not an invasion factor. Lipopolysaccharide (which is partially exposed in S+ bacteria) appeared to mediate invasion. Surprisingly, A. salmonicida did not show net growth inside fish cells cultured in the presence of gentamicin, as determined by viable bacterial cell counts. On the contrary, bacterial viability sharply decreased after cell infection. We thus concluded that the S-layer is an adhesin that promotes but does not mediate invasion of non-phagocytic fish cell lines. These cell lines should prove useful in studies aimed at characterizing the invasion mechanisms of A. salmonicida, but of limited value in studying the intracellular residence and replication of this invasive bacterium in vitro.

Aeromonas↗
PubMed2000

[Pathogenicity of Enterococcus spp. Characteristics of 169 hospital isolates].

BACKGROUND: To know the characteristics of Enterococcus spp. strains isolated in the hospital; to analyse the importance of this microorganism and its resistance to antimicrobial agents. PATIENTS AND METHODS: Retrospective analysis of the case histories of 169 patients with Enterococcus spp. isolates, selected at random at the Infanta Cristina Hospital in Badajoz. Investigation was carried out on: age, date of admission and discharge, clinical symptoms, risk factors, previous antibiotic treatment, clinical and microbiological evolution, recommended treatment and prescribed treatment. Identification of microorganisms and antibiogram with Pos Combo 41 microScam panels, read on Baxter WalkAway-40 equipment. RESULTS: The most frequently found species was Enterococcus faecalis. In 75 cases the isolations were polymicrobial. The enterococci were isolated mainly from urinary infections (27%), skin infections (20%), intrabdominal infections (14%) and infections from surgical wounds (14%). The existence of peripheral catheter was the main risk factor. All the strains of E. faecalis were susceptible to the glycopeptides. Two strains of Enterococcus faecium were not susceptible to vancomycin and one of these was not susceptible to teicoplanin. Mortality was from 21-27.5%. CONCLUSIONS: Enterococcus spp. is frequently isolated in nosocomial infections, although in approximately half the cases it is associated with other bacteria. For this reason, it is not always possible to determine its pathogenic contribution. The isolated strains, except two strains of E. faecium, are susceptible to vancomycin. A relation exists between high resistance to aminoglucosides and resistance to fluoroquinolones.

Enterococcus↗
PubMed1998

Surface-associated hsp60 chaperonin of Legionella pneumophila mediates invasion in a HeLa cell model.

HeLa cells have been previously used to demonstrate that virulent strains of Legionella pneumophila (but not salt-tolerant avirulent strains) efficiently invade nonphagocytic cells. Hsp60, a member of the GroEL family of chaperonins, is displayed on the surface of virulent L. pneumophila (R. A. Garduño et al., J. Bacteriol. 180:505-513, 1988). Because Hsp60 is largely involved in protein-protein interactions, we investigated its role in adherence-invasion in the HeLa cell model. Hsp60-specific antibodies inhibited the adherence and invasiveness of two virulent L. pneumophila strains in a dose-dependent manner but had no effect on the association of their salt-tolerant avirulent derivatives with HeLa cells. A monospecific anti-OmpS (major outer membrane protein) serum inhibited the association of both virulent and avirulent strains of L. pneumophila to HeLa cells, suggesting that while both Hsp60 and OmpS may mediate bacterial association to HeLa cells, only virulent strains selectively displayed Hsp60 on their surfaces. Furthermore, the surface-associated Hsp60 of virulent bacterial cells was susceptible to the action of trypsin, which rendered the bacteria noninvasive. Additionally, pretreatment of HeLa cells with purified Hsp60 or precoating of the plastic surface where HeLa cells attached with Hsp60 reduced the adherence and invasiveness of the two virulent strains. Finally, recombinant Hsp60 covalently bound to latex beads promoted the early association of beads with HeLa cells by a factor of 20 over bovine serum albumin (BSA)-coated beads and competed with virulent strains for association with HeLa cells. Hsp60-coated beads were internalized in large numbers by HeLa cells and remained in tight endosomes that did not fuse with other vesicles, whereas internalized BSA-coated beads, for which endocytic trafficking is well established, resided in more loose or elongated endosomes. Mature intracellular forms of L. pneumophila, which were up to 100-fold more efficient than agar-grown bacteria at associating with HeLa cells, were enriched for Hsp60 on the bacterial surface, as determined by immunolocalization techniques. Collectively, these results establish a role for surface-exposed Hsp60 in invasion of HeLa cells by L. pneumophila.

Adhesins, Bacterial↗
PubMedDate not supplied

[Long-term results of an eradication regime against Staphylococcus aureus in patients treated with peritoneal dialysis].

Catheter exit site infection (ESI) remains a common complication in peritoneal dialysis patients. All the efforts for controlling ESI have been focused on the preventive eradication of Staphylococcus aureus (SA) colonization, because this microorganisms has been shown to be implicated in most of ESI. The main aims of the present study was to analyse the long-term results from an eradicative regimen of SA colonization, and to compare them with those obtained from a historical control group. From january 1993 to december 1999, 60 unselected patients on PD underwent an exhaustive protocol of SA eradication. Every 30-45 days, cultures from nares and exit site were obtained in each patient. SA colonization in nares or exit site was treated with mupirocin, though the colonization of other microorganisms was not treated prophylactically. Thirty patients from the same unit who were followed between 1989-1992 served as historical control group. The rate of peritonitis and ESI, as well as the epidemiological data from the cultures were also analysed. The peritonitis and ESI rates were significantly less in the study group than those in the control group (0.398 +/- 0.553 vs 0.899 +/- 0.970 ep./pat/year, p = 0.002; and 0.102 +/- 0.235 vs 0.340 +/- 0.553 ep./pat/year, p = 0.004). The ESI rate caused by SA was also significantly less in the study group (0.018 +/- 0.096 vs 0.300 +/- 0.53 ep./pat/year, p = 0.0001), though there was a statistically nonsignificant increase in the ESI rate caused by gram negative microorganisms in the study group (0.066 +/- 0.194 vs 0.040 +/- 0.219 ep./pat./year). The percent of patients free of ESI was larger in the study group (80% vs 63%, p = 0.01), though the percent of patients with more than one ESI was the same in both groups (10%). Nasal and exit-site SA colonization occurred in 52% and 32% of the study patients. The rate of catheter loss was less in the study group, though it did not reach statistical significance (0.043 +/- 0.154 vs 0.178 +/- 0.443 losses/pat./year). In conclusion, the eradication of SA colonization is an efficacious measure for the control of ESI. However, further efforts should be carried out in order to control the emergence of gram negative microorganisms, and to discover which factors make a small proportion of PD patients to be more prone to develop ESI of whatever origin.

Catheterization↗