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Biomedical subjects

G Suarez

Publications and source records attributed to G Suarez.

At least 37 records · Page 2Linked to original sources
PubMed1992

Identification of coagulase negative staphylococci isolated from lambs as Staphylococcus caseolyticus.

A group of 17 strains of coagulase negative staphylococci isolated from slaughtered lambs, and which could not be identified with the conventional methods, exhibited high levels of DNA homology (92%) with the S. caseolyticus reference strain. The isolates described in this study provide a more extensive comprehension of S. caseolyticus. The original description of this species was based on only two strains isolated from milk. To our knowledge, S. caseolyticus had never been previously associated with animal microflora.

Abscess↗
PubMed1992

Production of staphylococcal enterotoxins and TSST-1 by coagulase negative staphylococci isolated from ruminant mastitis.

The production of staphylococcal enterotoxins (SE) and toxic shock syndrome toxin-1 by 40 coagulase negative staphylococci isolated from sheep, goat and cow mastitis was studied. Both ELISA double sandwich and Western blot were used to detect the production of these toxins. Only two strains of S. xylosus were enterotoxigenic, producing SEC. TSST-1 was seen to be produced by 5 strains of S. xylosus, 1 S. sciuri and 2 S. epidermidis. Results obtained by ELISA and by Western blot agreed in all cases except in one strain of S. epidermidis which was only positive using ELISA.

Animals↗
PubMed1992

Determination of the reactivities and cross-reactivities of monoclonal antibodies against staphylococcal enterotoxin A by indirect ELISA and immunoblot including a semiautomated electrophoresis system.

Eight murine monoclonal antibodies (Mabs) to staphylococcal enterotoxin A (SEA) were produced using standard hybridoma techniques. We studied reactivities and cross-reactivities by indirect ELISA and immunoblotting. Two of these Mabs (A5 and A7) reacted with five serovars (A-E) of SE in both systems. Only Mab A1 reacted specifically with the homologous toxin, while four Mabs reacted with SEA and SEE. Mabs A5 and A7 could be used to detect all five serovars of SEs in a single assay.

Animals↗
PubMed1992

Role of potassium tellurite and brain heart infusion in expression of the hemolytic phenotype of Listeria spp. on agar plates.

The influence of potassium tellurite (PT) and brain heart infusion agar (Difco), two components of modified Listeria selective agar medium (LSAMm), on the hemolytic phenotype of Listeria spp. was studied. L. monocytogenes and L. ivanovii displayed bigger zones of hemolysis on brain heart intusion agar compared with on Columbia agar base. The addition of PT increased the sizes of zones of hemolysis displayed by L. monocytogenes. This effect seemed to be produced by the enhancement of the cytolytic effect of listeriolysin O. PT decreased the hemolysis produced by L. ivanovii, and this effect seemed to be due to an inhibition of the sphingomyelinase C produced by this species.

Culture Media↗
PubMed1991

Different media and methodologies for the detection of aflatoxin production by Aspergillus flavus strains isolated from trout feed.

We have studied the aflatoxin producing capacity of 41 Aspergillus flavus strains isolated from the mycoflora present of natural media (wheat, rice and mixed feed) synthetic medium (Aflatoxin Producing Ability Medium) and semisynthetic media (Coconut Agar Medium and Glucose Yeast Extract Agar) were compared. Aflatoxins were analysed on days 4 and 8 post-inoculation under an incubation temperature of 28 degrees C. A total of 30 strains (75.7%) were producers on natural media as detected by Thin Layer Chromatography: 23 strains on wheat, 27 on rice and 12 on mixed feed. The results by qualitative fluorescence tests on synthetic and semisynthetic media were: 3 strains positive on Coconut Agar Medium (CAM) 1 on Glucose Yeast Extract Agar (GY + Agar) and none on Aflatoxin Producing Ability Medium (APA).

Aflatoxins↗
PubMed1991

Urinary incontinence. Not a 'normal' part of aging.

Urinary incontinence is a common problem that affects millions of elderly men and women and their caregivers. Evaluation of incontinence is easy and inexpensive and does not require hospitalization. A basic evaluation consists of history taking (including a review of drug use), physical examination, and appropriate laboratory testing. Urodynamic evaluation may also be necessary. Treatment may consist of behavior modification techniques (eg, Kegel exercises, biofeedback, bladder retraining), use of a mechanical device or pharmacologic agent, or surgery. Should medical and surgical methods fail, alternatives are available to ensure patients' well-being and comfort.

Aged↗
PubMed1990

Revision of the antigenic structure of genus Listeria.

O-antigenic structure of genus Listeria was studied, using antisera (obtained from rabbits) against different O-antigens of reference strains of each serovar. The titres of sera were determined by agglutination using antigens of the same reference strains as well. Some differences from the actual scheme were found: serum antifactor-IX gave a lower titre than expected against antigens 4ab and 6b, while the titre observed against antigen 4b was higher than the expected in this case. Serum antifactor-VIII presented a higher titre than could be expected against antigen 6b. The strains of serovars 4d and 4e used in this experience were impossible to distinguish, and could have been classified in the same serovar. We could not obtain serum antifactor-XI from serovar 6b after several trials. From these differences we propose some modifications of the current antigenic scheme of genus Listeria.

Antibodies, Bacterial↗
PubMed1990

Revision of the validity of CAMP tests for Listeria identification. Proposal of an alternative method for the determination of haemolytic activity by Listeria strains.

The validity of CAMP tests with Staphylococcus aureus and Rhodococcus (Corynebacterium) equi as defined for Listeria identification was revised. This characterization method appeared to be unreliable for two reasons: first, a positive CAMP test with R. equi is not specific for Listeria ivanovii as Listeria monocytogenes (and Listeria seeligeri) give also a clear positive reaction; second, doubtful reactions could be observed with S. aureus when assaying haemolytic and non-haemolytic Listeria strains (possibility of false negative and false positive results; subjectivity of the interpretation). The use of a Microplate technique previously described instead of CAMP tests is proposed for the reliable demonstration of the haemolytic character of Listeria in the routine identification of these organisms.

Bacterial Typing Techniques↗
PubMed1989

Continent urinary diversion in gynecologic oncology.

Pelvic exenteration is a salvage procedure used primarily for recurrent gynecologic carcinoma. Up to the present time, an ileal or colon conduit has been used for urinary diversion and the patient remains incontinent of urine. This is a preliminary report of nine patients with gynecologic carcinoma in whom a continent urinary diversion procedure was performed. A segment of distal ileum, the ascending colon, and part of the transverse colon are used to create the colonic reservoir. The segment of colon is opened along the tenia and folded onto itself. The walls of the ascending and transverse colon are anastomosed to detubularize this segment of bowel and eliminate the transient high pressure of the colon. Surgical staples are used for the anastomosis. The segment of ileum is tapered and three purse-string sutures (2-O silk) are placed at the level of the ileocecal valve to achieve continence. The short segment of ileum is then exteriorized as a stoma through which the patient catheterizes. Antirefluxing, non-tunneled ureterocolonic anastomoses are performed. The anterior wall of the reservoir is closed with absorbable staples. Postoperative urodynamic studies have shown maximum capacity of 750 ml and the area of continence to be at the ileocecal valve where the purse-string sutures are placed. All patients are continent and postoperative radiographs were negative for reflux. Follow-up was 6 to 12 months. The colonic reservoir is a capacious low-pressure system and warrants further clinical trials in patients with gynecologic cancer.

Colon↗
PubMed1989

Preliminary evidence that different domains are involved in cytolytic activity and receptor (cholesterol) binding in listeriolysin O, the Listeria monocytogenes thiol-activated toxin.

The inactive truncated 52 Kilodaltons (kDa) Listeriolysin O (LLO) produced by a transposon Tn1545-induced Listeria monocytogenes non-hemolytic/avirulent mutant previously described (Gaillard et al. (1986) Infect. Immun. 52, 50-55), that lacks a 48 aminoacid fragment at the C-terminal end including the single cysteine residue essential for activity (Mengaud et al. (1988) Infect. Immun. 56, 766-772), bound to the SH-cytolysin membrane receptor cholesterol, as did the active 60 kDa toxin. These results indicate that the missing fragment is a functionally important region needed in the 60 kDa LLO to cause membrane-disruption but not to bind to cholesterol, which strongly suggests that in LLO (and presumably in the other SH-cytolysins, in accordance with their structural and functional homologies) different domains are involved in cytolytic activity and cholesterol binding. The cysteine residue contained in the missing fragment, therefore, would not be essential for cholesterol binding, as is currently thought, rather it seems to be essential specifically for cell lysis.

Bacterial Toxins↗
PubMed1989

Nontunneled ureterocolonic anastomosis: an alternate to the tunneled implantation.

A nontunneled, nonrefluxing ureterocolonic implantation was performed in 32 patients who underwent construction of a continent colonic reservoir with a tapered distal ileum, and in 6 who underwent bladder replacement or urinary unidiversion with an ileocolonic segment. Between January 1986 and June 1988, 76 ureterocolonic anastomoses were performed with a success rate of 96%. Our preliminary report shows that this technique is a valuable alternative to the tunneled ureterocolonic anastomosis for various reconstructive procedures.

Anastomosis, Surgical↗
PubMed1989

Purification and characterization of two Listeria ivanovii cytolysins, a sphingomyelinase C and a thiol-activated toxin (ivanolysin O).

The strong bizonal hemolysis on blood agar and the positive CAMP reaction with Rhodococcus equi denotes the production of two different cytolytic factors by Listeria ivanovii. One was characterized as a thiol-activated (SH) cytolysin of 61 kilodaltons and was termed ivanolysin O (ILO) since data suggested that it is different from listeriolysin O, the SH-cytolysin produced by Listeria monocytogenes. The other is a 27-kilodalton hemolytic sphingomyelinase C that was found to be the cytolytic factor responsible for the halo of incomplete hemolysis synergistically enhanced by R. equi exosubstances. When thiol-disulfide exchange affinity chromatography and gel filtration were applied to the purification of ILO from concentrated L. ivanovii culture supernatants, the copurification of the two cytolysins was observed. This phenomenon seems to be due to the formation of intermolecular disulfide bonds between ILO and the sphingomyelinase, since the latter was found to contain free SH groups, not essential for the activity. These SH groups could react with the single cysteine residue characteristically present in the SH-cytolysins, forming a dimeric cytolytic complex. The purification of ILO was achieved by a further gel filtration with a reducing agent (dithiothreitol) in the eluent. A method for the purification of the sphingomyelinase based on selective sequestration of ILO from the L. ivanovii concentrated culture supernatant by the SH cytolysin target molecule cholesterol and thiol-disulfide affinity chromatography is described.

Bacterial Toxins↗
PubMed1989

Direct isolation (without enrichment) of Listeria monocytogenes in milk.

In the present work we have developed a direct method (without enrichment) for the isolation of listeriae in milk, using the combinated action of SDS (sodium dodecyl sulphate), centrifugation and selective media. It is possible to identify even 0.5 listeriae/ml amongst 7.2 x 10(7) c.f.u. contaminants/ml.

Animals↗
PubMed1989

Nonenzymatic browning of proteins and the sorbitol pathway.

As a result of the operation of the sorbitol pathway fructose levels increase in various tissues in diabetes. In vitro glycation of protein by fructose (fructation) leads to protein bound fluorescence generation at a rate ten times that resulting from glycation by glucose (glucation), possibly by a faster conversion of Amadori groups to fluorophores. Therefore, tissue protein fluorescence might, in part, result from fructation. Evidence is presented for the occurrence of in vivo fructation of skin collagen and soluble lens proteins in diabetic rats. Fructation-induced protein functional alterations might underlie complications of diabetes in tissues where the sorbitol pathway is active.

Animals↗
PubMed1989

Serological diagnosis of listeriosis in man, sheep and rabbit by immunoperoxidase technique.

Due to the already demonstrated specificity and usefulness of Listeria intracellular antigen in paraffin-embedded tissues for the direct diagnosis, we have used an indirect immunoperoxidase technique for the serological diagnosis of listeriosis in man, sheep and rabbit. This technique has been compared with other immunoperoxidase techniques (PAP) using the same antigen, and with other serlogical techniques--ELISA and microplate agglutination test--using two kinds of Listeria antigens, live formalinized and heat at 100 degrees C for one hour whole cells.

Agglutination Tests↗
PubMed1988

Considerations on the distribution of aflatoxigenic Aspergillus flavus in feeds.

The distribution of aflatoxin producing isolates of the Aspergillus flavus group in feeds was studied. Aflatoxin production was investigated by a sequential method previously reported (fluorescence in Coconut Agar Medium, rapid extraction from a wheat medium, and total extraction from the same wheat medium). Twenty-seven of 32 samples contained A. flavus, and 21 of them had at least one aflatoxicogenic isolate of A. flavus. Of the 115 isolates analysed, 65 produced aflatoxins, mainly B aflatoxins.

Aflatoxins↗
PubMed1988

Iatrogenic chordee following insertion of inflatable penile prosthesis.

Chordee deformity is a rare complication following insertion of the inflatable penile prosthesis through a penoscrotal incision. The deformity occurs as a result of failure to inflate and deflate the device and to maintain the penis against the abdomen in the immediate postoperative period. When this occurs it can be corrected by incision of the fibrous scar and replacement with synthetic graft material.

Humans↗