Biomedical subjects

A Castillo

Publications and source records attributed to A Castillo.

At least 37 records · Page 2Linked to original sources

PubMed2000

[Synovial sarcoma of the tongue. Case report and review of the literature].

Primary synovial sarcoma of the head and neck is a rare entity, nevertheless the literature count on 80 published cases, among them 7 linguals. We contribute with another case: a synovial sarcoma of the tongue, in a 26-year-old man; having a biphasic tumor pattern, with two malignant constituents, epithelial and sarcomatous, similar to other of the same location. Laboratory tests: histochemical, immunohistochemical and electron microscopic were done in order to state the tumor's histogenesis. Our results suggest a pluripotential mesenchymal origin instead of a synovial origin, because the epithelial character of one of the tumor constituents was obviously epithelial.

Adult↗

PubMed1999

A new double-stranded RNA mycovirus from Botrytis cinerea.

A simple double-stranded RNA mycovirus was detected in a wild-type Botrytis cinerea 55k strain. The virus was located in the fungus cytoplasm as free particles of approximately 28 nm in diameter. The mycovirus possesses a single double-stranded genome segment of 1.8 kilobase pairs (kbp) encapsidated within an isometric protein coat whose main structural component is a polypeptide of 68 kDa. Cells infected with this virus showed an important degree of cellular degeneration.

Botrytis↗

PubMed1999

The PecT repressor coregulates synthesis of exopolysaccharides and virulence factors in Erwinia chrysanthemi.

Erwinia chrysanthemi 3937 synthesizes an exopolysaccharide (EPS) composed of rhamnose, galactose, and galacturonic acid. Fourteen transcriptional fusions in genes required for EPS synthesis, named eps, were obtained by Tn5-B21 mutagenesis. Eleven of them are clustered on the chromosome and are repressed by PecT, a regulator of pectate lyase synthesis. In addition, expression of these fusions is repressed by the catabolite regulatory protein, CRP, and induced in low osmolarity medium. The three other mutations are located in genes that are not regulated by pecT. A 13-kb DNA fragment containing pecT-regulated eps genes has been cloned. All the genes identified on this fragment are transcribed in the same orientation and could form a large operon. The promoter region of this operon has been sequenced. It contains a JUMP-start sequence, a sequence required for the expression of polysaccharide-associated operons. E. chrysanthemi 3937 produces a systemic soft rot on its host Saintpaulia ionantha. An eps mutant was less efficient than the wild-type strain in initiating a maceration symptom, suggesting that production of EPS is required for the full expression of the E. chrysanthemi virulence.

Artificial Gene Fusion↗

PubMed1999

Decontamination of beef carcass surface tissue by steam vacuuming alone and combined with hot water and lactic acid sprays.

Hot beef carcass surface regions (outside round, brisket, and clod) contaminated with feces spread over a 5-cm2 (1-in2) area were cleaned using a steam-vacuum spot-cleaning system alone or combined with subsequent sanitizing treatments of hot water (95 degrees C at the nozzle), or warm (55 degrees C) 2% lactic acid spray, or combinations of these two sanitizing methods. These treatments were compared for effectiveness in reducing aerobic plate counts (APC) and counts of Enterobacteriaceae, total coliforms, thermotolerant coliforms, and Escherichia coli. All treatments significantly reduced the numbers of each group of bacteria on beef carcass surfaces. However, reductions obtained by steam vacuuming were significantly smaller than those obtained by a combination of steam vacuuming with any sanitizing treatment. No differences in bacterial reductions were observed between different carcass surface regions. Steam vacuuming reduced the number of different indicator organisms tested by ca. 3.0 log cycles but also spread the bacterial contamination to areas of the carcass surface adjacent to the contaminated sites. This relocated contamination after steam vacuuming was most effectively reduced by spraying with hot water and then lactic acid. This combined treatment consistently reduced the numbers of Enterobacteriaceae, total and thermotolerant coliforms, and E. coli to undetectable levels (<1.0 log10 CFU/cm2) on areas outside the initial 5-cm2 inoculated areas.

Abattoirs↗

PubMed1999

Reduction of Escherichia coli O157:H7 and Salmonella typhimurium on beef carcass surfaces using acidified sodium chlorite.

The efficacy of a phosphoric acid-activated acidified sodium chloride (PASC) spray and a citric acid-activated acidified sodium chlorite (CASC) spray applied at room temperature (22.4 to 24.7 degrees C) in combination with a water wash was compared with that of a water wash only treatment for reduction of Escherichia coli O157:H7 and Salmonella Typhimurium inoculated onto various hot-boned individual beef carcass surface regions (inside round, outside round, brisket, flank, and clod). Initial counts of 5.5 and 5.4 log CFU/cm2 were obtained after inoculation with E. coli O157:H7 and Salmonella Typhimurium, respectively. Initial numbers for both pathogens were reduced by 3.8 to 3.9 log cycles by water wash followed by PASC spray and by 4.5 to 4.6 log cycles by water wash followed by CASC spray. The sprays consisted of applying 140 ml of the appropriate sanitizing solution for 10 s at 69 kPa. Corresponding reduction values obtained by water wash alone were 2.3 log. The performance of CASC appeared to be consistently better than that of PASC. In general, no effect of the carcass surface region was observed on the log reductions for either pathogen, except for the inside round, which consistently had lower reductions. Both PASC and CASC were capable of effectively reducing pathogens spread to areas beyond the initial contaminated area of the cuts to levels close to or below the counting method detection limit (0.5 log CFU/cm2). However, 30 to 50% of the carcasses treated by these antimicrobial solutions still yielded countable colonies. Results of this study indicate that acidified sodium chlorite sprays are effective for decontaminating beef carcass surfaces.

Abattoirs↗

PubMed1999

[A lymphoepithelial cyst of the parotid gland in an advanced stage of HIV infection. A rare association].

Parotid lymphoepithelial cyst is an unusual morbid entity which incidence has been increased lately because of its association to early stages of HIV infection. We report the case of an heterosexual man, 39, ex-addicted to parenteral drugs, HIV positive, stage C3. Its left parotid gland presented with a lump of low rate growth which was with fine needle punctured and aspirate for biopsy and after followed by the mass removal. Cytological and histopathological examination confirmed the diagnosis (lymphoepithelial cyst). The aim for our work is to explain the clinic and pathological features of this condition and emphasize the fact of its possible presentation in positive HIV patients in advanced stages.

Adult↗

PubMed1998

The PecT repressor interacts with regulatory regions of pectate lyase genes in Erwinia chrysanthemi.

Erwinia chrysanthemi is a broad host range phytopathogenic enterobacterium responsible for soft-rot disease of many plant species. The pecT gene encodes a repressor that negatively regulates the expression of virulence factors, such as pectinases, motility or exopolysaccharide synthesis. The cloned pecT gene was overexpressed using a phage T7 system. The purification of PecT involved the use of a TSK-heparin column and delivered the PecT protein that was purified to near homogeneity. The purified repressor displayed a 34 kDa apparent molecular mass. Gel-filtration experiments revealed that the PecT protein is a dimer. Band-shift assays demonstrated that the tetramer of the PecT protein could specifically bind in vitro to the regulatory regions of the pectate lyase genes with variable affinities. In addition, we demonstrated that PecT represses its own synthesis by interacting independently with two 200 bp regions, R1 and R2, located from -382 to -632 and -17 to -234, respectively, from the distal P1 promoter and from -465 to -715 and -100 to -317 from the P2 proximal promoter. We propose a model that explains the regulation exerted by PecT on its target genes and that integrates the phenotype obtained with a PecT overproducing pec-1 mutant or a pecT mutant.

Bacterial Proteins↗

PubMed1998

Effect of bryostatin 1 on taxol-induced apoptosis and cytotoxicity in human leukemia cells (U937).

We have examined the effects of the macrocyclic lactone protein kinase C (PKC) activator bryostatin 1 on taxol-induced apoptosis and inhibition of clonogenicity in the human monocytic leukemia cell line U937. Exposure of cells to bryostatin 1 (10 nM; 15 hr) after (but not before) a 6-hr incubation with 0.5 microM taxol significantly increased apoptosis and resulted in an approximately 3 log reduction in clonogenicity. Cell cycle analysis revealed that the increase in apoptotic cells following bryostatin 1 treatment occurred primarily in the population undergoing taxol-mediated G2M arrest. The actions of bryostatin 1 were not attributable to potentiation of taxol-induced tubulin stabilization or to a reduction in the intracellular retention of taxol. Following exposure of cells to taxol, the Bcl-2 protein displayed an alteration in mobility that was not modified appreciably by bryostatin 1 treatment. The mobility shift in Bcl-2 protein from cells exposed to taxol followed by bryostatin 1 was eliminated by treatment of lysates with the protein phosphatase 2A (PP2A); the latter effect was blocked by okadaic acid. Treatment of cells with taxol followed by bryostatin 1 did not increase the amount of total Bax (compared with treatment with taxol alone), but did increase the amount of free Bax in the supernatant fraction. Finally, the ability of bryostatin 1 to potentiate taxol-induced apoptosis in U937 cells was mimicked closely by 2'-amino-3'-methoxyflavone (PD98059), a specific inhibitor of the mitogen-activated protein kinase (MAPK) kinase (MEK). Collectively, these findings indicate that bryostatin 1 increases the susceptibility of U937 cells to taxol-induced apoptosis and inhibition of clonogenicity. They also raise the possibility that this phenomenon may involve functional alterations in Bcl-2 and/or other proteins involved in regulation of the cell death pathway.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1998

Endothelial damage with cataract surgery techniques.

PURPOSE: To evaluate intraoperative endothelial damage after planned extracapsular cataract extraction (ECCE) with difference capsulotomy techniques and phacoemulsification. SETTING: San Carlos University Hospital, Castroviejo Institute, Madrid, Spain. METHODS: In this prospective, randomized study, 60 patients with senile cataract scheduled for cataract surgery were divided into three groups of 20 each: Group 1 had phacoemulsification; Group 2, planned ECCE with continuous curvilinear capsulorhexis; and Group 3, ECCE with letter-box capsulotomy. Preoperatively and 3 months postoperatively, endothelial cell density, percentage of hexagonality, and the cell size variation coefficient were determined by contact specular microscopy; endothelial permeability was examined by anterior segment fluorophotometry and central corneal thickness, by ultrasonic pachymetry. Results were analyzed using the two-tailed Student's t-test and analysis of variance. RESULTS: In all three groups, endothelial permeability and cell loss increased significantly from the preoperative values, but there were not significant differences among the postoperative values. Mean cell loss was 11.8% in Group 1, 12.8% in Group 2, and 10.1% in Group 3. There were no differences between the preoperative and postoperative morphometric indexes. Postoperative pachymetric measurements were not significant. CONCLUSIONS: Endothelial response was not statistically significantly different among the surgical techniques, although endothelial damage was lower in Group 3, which could indicate a protective effect of the anterior capsule during cataract extraction. Endothelial barrier function remained disturbed despite the apparent morphological stabilization.

Aged↗

PubMed1998

Immunologic and clinical evaluation of postsurgical necrotizing sclerocorneal ulceration.

PURPOSE: To perform a clinical, laboratory and pathologic evaluation in patients who had developed a postsurgical necrotizing sclerocorneal ulceration to detect a serious associated autoimmune disorder and to treat the ocular disease early. METHODS: Nine patients with postsurgical necrotizing sclerocorneal ulceration after uneventful cataract extraction were studied by means of immunohistochemical techniques on conjunctival resections, immunologic serologic studies, and rheumatologic evaluation. Nine healthy subjects who underwent uneventful cataract surgery were used as controls. RESULTS: The pathologic studies showed a local immunoglobulin M (IgM) and IgG deposition, increased human leukocyte antigen (HLA-DR) expression, and a significant T-helper cell participation in conjunctival biopsies in the most severe ulcerations, which were detected in four patients with underlying autoimmune systemic disorder (rheumatoid arthritis, 45%) and only a macrophagic infiltration in the mildest ulcers in patients (55%) without immune disorders. Serologic features included high titers of rheumatoid factor in the four (45%) patients with rheumatoid arthritis, nonspecific serologic immune alteration in three (33%) patients, and were unremarkable in two (22%) patients. The medical and immunologic evaluations were negative in the control cases. Topically administered cyclosporin A healed the ocular disease. CONCLUSION: A surgically induced local autoimmune reaction could occur in the incision area in patients with systemic vasculitic disease. There was no underlying systemic disorder in the mildest ulcers, and these ulcers could be due to a defect in the surgical technique. Our results suggest the need for a detailed systemic evaluation in patients with severe postsurgical necrotizing ulceration. Early diagnosis and aggressive medical treatment of the ocular disorder improves the visual outcome.

Aged↗

PubMed1998

Use of hot water for beef carcass decontamination.

Hot water treatment of beef carcass surfaces for reduction of Escherichia coli O157:H7, Salmonella typhimurium, and various indicator organisms was studied using a model carcass spray cabinet. Paired hot carcass surface regions with different external fat characteristics (inside round, outside round, brisket, flank, and clod) were removed from carcasses immediately after the slaughter and dressing process. All cuts were inoculated with bovine feces containing 10(6)/g each of rifampicin-resistant E. coli O157:H7 and S. typhimurium, or with uninoculated bovine feces. Surfaces then were exposed to a carcass water wash or a water wash followed by hot water spray (95 degrees C). Counts of rifampicin-resistant Salmonella and E. coli or aerobic plate count (APC) and coliform counts were conducted before and after each treatment. All treatments significantly reduced levels of pathogens from the initial inoculation level of 5.0 log(10) CFU/cm2. Treatments including hot water sprays provided mean reductions of initial counts for E. coli O157:H7 and S. typhimurium of 3.7 and 3.8 log, APC reductions of 2.9 log, and coliform and thermotolerant coliform count reductions of 3.3 log. The efficacy of hot water treatments was affected by the carcass surface region, but not by delaying the treatment (30 min) after contaminating the surface. Verification of efficacy of hot water interventions used as critical control points in a hazard analysis critical control point (HACCP) system may be possible using coliform counts.

Animals↗

PubMed1998

Chemical dehairing of bovine skin to reduce pathogenic bacteria and bacteria of fecal origin.

A chemical dehairing process was applied to artificially contaminated bovine hide to evaluate the effect on populations of Escherichia coli O157:H7 and Salmonella Typhimurium, as well as other strains of E. coli, total coliforms, and aerobic plate counts (APC). Pieces of hide (4 cm2) were contaminated with bovine feces inoculated with both rifampicin-resistant E. coli O157:H7 and S. Typhimurium to yield a final count of each pathogen of ca. 5.0 log10 CFU/cm2, or with noninoculated feces which produced an approximate final APC of 6.0 log10 CFU/cm2 and a coliform and E. coli count of 5.0 log10 CFU/cm2. Counts of pathogens, APC, coliforms, and E. coli were conducted before and after applying the dehairing treatment. S. Typhimurium and E. coil O157:H7 populations were significantly reduced from initial numbers (5.1 to 5.3 log10 CFU/cm2) to levels below the detection limit of 0.5 log10 CFU/cm2 after chemical dehairing. APC, coliforms, and E. coli counts were also reduced significantly after dehairing, with reductions of 3.4 for APC, 3.9 for coliforms, and > 4.3 log10 CFU/cm2 for other E. coli strains. Since the hide is a major source of fecal contamination of beef carcass surfaces, chemical dehairing may be beneficial in reducing overall contamination of carcasses.

Animals↗

PubMed1998

Comparison of water wash, trimming, and combined hot water and lactic acid treatments for reducing bacteria of fecal origin on beef carcasses.

Cleaning treatments, such as high-pressure water wash at 35 degrees C or trim, alone and combined with sanitizing treatments, such as hot water (95 degrees C at the source), warm (55 degrees C) 2% lactic acid spray, and combinations of these two sanitizing methods, were compared for their effectiveness in reducing inoculated numbers (5.0 to 6.0 log CFU/cm2) of Salmonella typhimurium, Escherichia coli O157:H7, aerobic plate counts, Enterobacteriaceae, total coliforms, thermotolerant coliforms, and generic E. coli on hot beef carcass surface areas in a model carcass spray cabinet. Log reductions in numbers of all tested organisms by water wash or trim alone were significantly smaller than the log reductions obtained by the different combined treatments. Regardless of the cleaning treatment (water wash or trim) or surface area, the range for mean log reductions by hot water was from 4.0 to > 4.8 log CFU/cm2, by lactic acid spray was from 4.6 to > 4.9 log CFU/cm2, by hot water followed by lactic acid spray was from 4.5 to > 4.9 log CFU/cm2, and by lactic acid spray followed by hot water was from 4.4 to > 4.6 log CFU/cm2, for S. typhimurium and E. coli O157:H7. Identical reductions were obtained for thermotolerant coliforms and generic E. coli. No differences in bacterial reductions were observed for different carcass surface regions. Water wash and trim treatments caused spreading of the contamination to other areas of the carcass surface while providing an overall reduction in fecal or pathogenic contamination on carcass surface areas. This relocated contamination after either water wash or trim was most effectively reduced by following with hot water and then lactic acid spray. This combined treatment yielded 0% positive samples for S. typhimurium, E. coli O157:H7, thermotolerant coliforms, and generic E. coli on areas outside the inoculated areas, whereas percent positive samples after applying other combined treatments ranged from 22 to 44% for S. typhimurium, 0 to 44% for E. coli O157:H7, and 11 to 33% for both thermotolerant coliforms and generic E. coli. From data collected in this study, it is possible to choose an effective, inexpensive treatment to reduce bacterial contamination on beef carcasses. In addition, the similar reduction rates of total coliforms, thermotolerant coliforms, or generic E. coli may be useful in identifying an indicator to verify the effectiveness of the selected treatment as a critical control point in a Hazard Analysis and Critical Control Point program.

Animals↗

PubMed1997

A double-stranded RNA mycovirus in Botrytis cinerea.

In wild-type Botrytis cinerea CVg25 strain we have detected the presence of extrachromosomal genetic elements corresponding to double-stranded RNA molecules. These genetic elements have been designated L, M1 and M2 with molecular sizes of 8.3, 2.0 and 1.4 kb, respectively. The visualization by electron microscopy of mycelium ultrathin sections from B. cinerea CVg25 showed the presence of isometric virus-like particles of about 40 nm in diameter. Linear sucrose gradient centrifugation of mycelium-free extracts was done to determine if the double-stranded RNAs were associated with virus-like particles. The gradient profile obtained at 260 and 280 nm revealed a major peak that was analyzed by both agarose-gel electrophoresis and electron microscopy. It was observed that only the L-double-stranded RNA molecule copurified with isometric virus-like particles. These virus-like particles had a similar morphology and size as those detected by electron microscopy in the mycelium sections. These results suggest that only the L-double-stranded RNA would be encapsidated.

Extrachromosomal Inheritance↗

PubMed1997

Early versus late necrosectomy in severe necrotizing pancreatitis.

BACKGROUND: Debate as to whether surgery in severe necrotizing pancreatitis (SNP) should be done early or late has been present ever since the disease was described. There are no prospective, randomized studies addressing this specific issue. METHODS: Patients with SNP, documented clinically, with Ranson's criteria, and dynamic pancreatography (DP) findings were randomly allocated in two groups for treatment. Group A included early necrosectomy (within 48 to 72 hours of onset) and group B, late necrosectomy (at least 12 days after onset). Both groups continued with open packing and staged necrosectomies. Cultures were obtained at each laparotomy and necrosis was verified histologically in all instances. RESULTS: During a 36-month study period, 150 patients with unequivocal acute pancreatitis were admitted for treatment. Forty-one with SNP initially entered the study; there were 5 drop outs. Patients in group A (25) and group B (11) had no difference in distribution by gender or mean age, etiology, mean Ranson's signs (4 versus 3.8), DP findings, rate of infected necrosis, or necrosectomies required per patient. Although the mortality rate (58% versus 27%) did not reach statistical significance, the odds ratio for mortality was 3.4 times higher in group A, which made us finish the study. CONCLUSION: This prospective, randomized study from a single institution clearly demonstrates that early intensive conservative treatment with late necrosectomy for selected cases is the current rationale approach for SNP.

Adult↗

PubMed1997

Urodynamically based modification of Mitrofanoff procedure.

This paper reviews our experience with the Mitrofanoff principle as applied in eight patients. Of four patients with post-traumatic urethral stricture, three required the appendix as continent catheterizable conduit, with a modified appendicovesical anastomosis technique-that is, without a submucosal tunnel- and in one patient, the remnant ureter of a previous simple nephrectomy was used. Of the four remaining patients, one with a hypotonic bladder and three with urethral stricture, a complete laparoscopic approach was used to perform the same modified Mitrofanoff procedure with the appendix. With a mean follow-up of 19.5 months, all patients were completely dry. Only three patients had persistently positive urine cultures, but without evidence of renal function impairment. The modified direct appendicovesical anastomosis technique reduces the operative time, has a lower complication rate, and allows us to use a laparoscopic approach with the resulting benefits of a minimally invasive surgical procedure. As shown in urodynamic tests, urinary continence is preserved.

Adolescent↗

PubMed1997

In-vitro susceptibility, tolerance and glycocalyx production in Streptococcus mutans.

We studied the presence of high-level resistance to aminoglycosides, penicillin tolerance and glycocalyx production in 160 isolates of Streptococcus mutans. Susceptibility to amoxycillin, cefazolin, imipenem, erythromycin, clindamycin, vancomycin and teicoplanin was also investigated. Of the isolates analysed, 58.8% produced glycocalyx in vitro and 2.5% were penicillin-tolerant. High-level resistance to streptomycin was found in 16.3% of the isolates, but all were sensitive to all other antibiotics tested. We found no significant relationship between glycocalyx production and high-level streptomycin resistance, penicillin tolerance or antibiotic susceptibility, except for a greater susceptibility to clindamycin and vancomycin in isolates that produced glycocalyx. Although our findings reflect the clinically favourable pattern of susceptibility currently found in this species, the appearance in some isolates of resistance, tolerance and glycocalyx production should be investigated because of the risks involved in endocarditis caused by S. mutans.

Aminoglycosides↗

PubMed1997

Characterization of the pecT control region from Erwinia chrysanthemi 3937.

Erwinia chrysanthemi synthesizes and secretes pectate lyases that attack components of the plant cell wall and, therefore, play a major role in the pathogenesis of soft rot disease. We isolated a new mutant (designated pec-1), by Tn5 mutagenesis, that displays weak pectate lyase production and decreased motility and mucoidicity. Maceration and pathogenicity tests done on different plant organs showed that the pec-1 strain displays a reduced virulence compared to that of the parental strain. The Tn5 insertion was localized between the pelL and the out loci and defines a new regulatory region. Sequencing of the pec-1::Tn5 insertion revealed that pec-1 is tightly linked to the pecT regulatory gene that also controls pectate lyase synthesis. Moreover, the pecT mutation is dominant over the pec-1 mutation, suggesting that these two loci are involved in the same regulatory network. We demonstrated, by Northern blot analysis, that the pec-1::Tn5 insertion provokes derepression of pecT transcription and defines a cis-acting element. Introduction of the pecT gene in trans of a pecT::uidA fusion induced a decrease of pecT::uidA transcription, indicating a negative autoregulation. Band shift experiments confirmed that the PecT repressor specifically interacts with the pecT regulatory region. We also demonstrated that the PecT protein interacts with the regulatory region of the pelD gene encoding a pectate lyase. Therefore, the abolition of the pecT autoregulation in the pec-1 mutant provokes an overproduction of the PecT repressor that is responsible for the decrease of pectate lyase synthesis. Mutagenesis of the pecT regulatory region revealed the presence of two sites in which insertions reproduced the pec-1 phenotype. This result suggests that pecT autoregulation requires the presence of two functional operator sites. From this study, we propose that the PecT repressor binds to these two sites, generating a loop that blocks pecT transcription.

Bacterial Proteins↗