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Biomedical subjects

A Castillo

Publications and source records attributed to A Castillo.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1997

Deposits of topical norfloxacin in the treatment of bacterial keratitis.

PURPOSE: Fluoroquinolone solutions are widely used in therapy of bacterial keratitis. These drugs are safe, and their ocular side effects are mild and not serious in nature. The most frequent untoward effect associated with ciprofloxacin therapy has been a white crystalline deposit. This deposit has not been reported after using the other commercially available quinolones, ofloxacin and norfloxacin. METHODS: We present three cases of norfloxacin deposits after treatment of bacterial keratitis. RESULTS: In the three cases, the norfloxacin was substituted for another antibiotic effective against the bacteria, and the precipitate spontaneously resolved in all cases within a few days with no untoward ocular effect. CONCLUSION: Crystalline corneal deposits can develop during topical norfloxacin therapy. The exact factors contributing to the formation are unknown, although the differences in the tear pH/solubility could be involved. Clinicians should be aware of this ocular side effect.

Aged↗
PubMed1997

[Post-infectious demyelinating diseases].

Post-infectious demyelinating disorders are uncommon. In the Hospital Pediatrico de la Misericordia de Santafé de Bogotá there were 14 cases in three years. The commonest age group was the new born, as is found in the literature. The infections involved in these neurological changes are probably viral, since at the time the patient is seen most symptoms have cleared up spontaneously. According to several authors, the viruses are most often found to be those of measles or mumps. Between the infection and the development of neurological symptoms there is an interval of approximately two weeks. The main clinical findings are motor changes such as hemiparesis, involvement of cranial nerves and alterations of consciousness. The aetiology is not completely clear. Firm diagnosis is made on histopathological studies which are seldom available. Usually neuroimaging techniques and cerebrospinal fluid analysis are the basis of the diagnosis. Computerized axial tomography and magnetic resonance are the most useful noninvasive techniques for assessing the involvement of the white matter, the extent and sites of the lesions. It is useful to know the classification of the demyelinating disorders so as to prescribe, the most suitable treatment and give the prognosis in each case. There is still no specific treatment for these disorders. Supportive measures, the control of epileptic crises and the prevention of complications are the main aims. This paper reviews the definition, classification, diagnosis and management of these disorders.

Demyelinating Diseases↗
PubMed1996

Tissue distribution and structure of barrier cells in the hematopoietic and lymphoid organs of salmonids.

BACKGROUND: Barrier cells have been recognized as a discrete group of fibroblastic- or myofibroblastic-like cells located in the lymphoid and hematopoietic organs of mammals. This paper reports the results of a morphological study of the main lymphoid organs of three salmonid species, in which cells structurally similar to the mammalian barrier cells were observed in healthy animals. METHODS: The spleen, kidney, and thymus of fingerlings of rainbow trout, Oncorhynchus mykiss, and Coho salmon, Oncorhynchus kisutch, and of adult brown trout, Salmo trutta fario, were processed for electron microscopy study using various fixation methods. Semithin sections were used for the Periodic Acid-Schiff (PAS) staining technique, and for the demonstration of the endogenous peroxidase activity. RESULTS: The kidney and spleen of all the species contained a variable, but usually low, number of electron-dense, elongated, and branched cells, ultrastructurally similar to the mammalian barrier cells. They also occurred in the thymus of some brown trout and Coho salmon, but not of rainbow trout. The electron density of this cell type was present after the various types of fixation procedures. They show numerous ribosomes, well-developed secretory organelles, electron-clear vesicles, large granules, and microfilaments. In all the salmonid species, barriers cells were positive for PAS staining and for endogenous peroxidase activity. A small number of barrier cells were in mitosis. In the different organs barrier cells appeared as isolated cells, or forming syncytial networks. They were found lining the blood sinusoids of the splenic red pulp and of the renal hematopoietic tissue, in the periellipsoidal sheaths, and closely associated with erythropoietic and plasmacytopoietic foci. CONCLUSIONS: Our results demonstrate the presence of cells closely resembling mammalian barrier cells in the hematopoietic and lymphoid organs of salmonids. The structure and tissue distribution of the salmonid barrier cells are discussed in relation to the functional roles described for this cell type in mammals.

Animals↗
PubMed1996

Analysis of the blood-retinal barrier: its relation to clinical and metabolic factors and progression to retinopathy in juvenile diabetics. A 4-year follow-up study.

BACKGROUND: The study was carried out to evaluate the correlation between blood-retinal barrier (BRB) permeability and the development of diabetic retinopathy (DR) and to assess the metabolic and clinical factors related to DR over a 4-year period by means of vitreous fluorophotometry (VF). METHODS: Thirty-five type I diabetics with no retinopathy, age 7-21 years (mean 14.32 +/- 2.1 years) were enrolled in this longitudinal study. Two visits included standard ophthalmological examination, fluorescein angiography and VF were performed, on entry into the study and 4 years later. The following risk factors in DR were analyzed: age, duration of diabetes, blood pressure, cholesterol, triglycerides, fasting blood glucose levels, glycosylated hemoglobin (HbA1c), insulin dose/kg body weight (IDBW), fructosamine and albuminuria. To estimate the BRB permeability we adopted the vitreous penetration ratio transmittance (VPRt) value. RESULTS: At 4-year follow-up the mean VPRt had significantly increased. During that time 13 patients developed DR and their final mean VPRt was significantly higher than that in non-DR patients. Additionally, the initial mean VPRt was higher but not significantly so, in patients that later developed DR than in non-DR subjects. A constant linear correlation was found between VPRt and duration of diabetes, HbA1c and microalbuminuria. CONCLUSION: VF is a quantitative method that could measure and predict the breakdown of the BRB before angiographic retinopathy in type I diabetics. The major clinical and metabolic factors related to alterations in the BRB are duration of diabetes, HbA1c and microalbuminuria.

Adolescent↗
PubMed1996

HLA-B27--associated uveitis presenting with diffuse vitritis.

A 26-year-old man complained of a sudden decrease in vision in the left eye. He had a past medical history of pauciarticular juvenile rheumatoid arthritis with a positive HLA-B27 haplotype and negative antinuclear antibodies and later development of ankylosing spondylitis. His ocular history was unremarkable. An ophthalmic examination revealed a predominant diffuse vitritis (3+) in the left eye. The uveitis improved after treatment with topical and systemic steroids. Following an extensive clinical and laboratory evaluation, a final diagnosis of HLA-B27-associated uveitis was made. Although uncommon, diffuse vitritis can occur in the setting of this uveitis and may be a predominant symptom.

Adult↗
PubMed1996

Initial pH as a determining factor of glucose consumption and lactic and acetic acid production in oral streptococci.

Lactic and acetic acid production was evaluated from six strains of oral streptococci, viz Streptococcus gordonii, Streptococcus mutans, Streptococcus oralis, Streptococcus salivarius, Streptococcus sanguis and Streptococcus sobrinus cultured in the presence of 1, 5, 10 mM glucose and without glucose, at initial pH values of 5, 5.5, 6 and 7. S. sobrinus and S. salivarius caused the greatest decreases in pH. At pH values of 5 and 5.5, lactic acid and acetic acid production in the species tested was discordant with residual glucose levels. Acid production from protein was especially great in S. mutans and S. salivarius.

Acetic Acid↗
PubMed1996

[Enterovirus meningoencephalitis in the last 5 years].

The results of the study of Enterovirus as viral meningoencephalitis producing agents, carried out from 1990 to 1994, are described, 546 feces samples, 95 cerebrospinal fluids and 1,058 matched sera were studied and obtained from 1,388 patients clinically diagnosed with this disease. Samples for viral isolation were inoculated into two different cellular systems. The highest number of isolation was found in diploid cells from human fibroblast. Antibody determinations were carried out by a neutralization test (micromethod) with 11 Enterovirus antigens (Echo 4, 6, 9, 11 and 30; and Coxsackie B1, 2, 3, 4, 5 and 6) and in epidemic periods with the isolated virus. During the years under study, 2 epidemic outbreaks took place: on caused by Coxsackie A9 (1990-1991) and the other one by Echo 30 (1994). A greater positivity to Echo 6 and 11 was found among the matched sera.

Antibodies, Viral↗
PubMed1995

Influence of topical cyclosporine A and dissolvent on corneal epithelium permeability of fluorescein.

The corneal stroma is the major barrier to penetration for the lipophilic Cyclosporine A (CsA) molecule and prevents the use of the common ophthalmic solvents. At present, corn oil, castor oil and olive oil are the three most commonly used vehicles. The aim of this study was to determine the effect that topically applied CsA dissolved in different oils has on corneal epithelial permeability measured by fluorophotometry. Forty healthy volunteers, with absence of ocular or systemic disease and not receiving topical or systemic drugs were enrolled. Measurements were taken before and 45 min after the instillation of 40 microliters of a 2% aqueous solution of sodium fluorescein without preservatives. Basal corneal permeability and the permeability 24 h after the instillation of 2% CsA-olive oil, olive oil alone, 2% CsA-castor oil, castor oil alone, 2% CsA-corn oil and corn oil alone, were calculated. To prepare the topical 2% CsA, a Sandimmun oral solution (Sandoz, Basel, Switzerland) was employed under sterile conditions. We found that epithelial permeability 24 h after the instillation of any CsA formulations or solvents increased more than 6.62 times (p <0.001). No differences in corneal permeability values were found between any of the CsA formulations and the vehicles. We conclude that oils used to dissolve CsA are mainly responsible for the increased corneal epithelial permeability. No differences were found in the effects of the tested solvents on corneal epithelial permeability.

Administration, Topical↗
PubMed1995

Evaluation of the automicrobic system for the identification of Streptococcus mutans.

The performance of the Automicrobic System with the Vitek gram-positive identification card (bioMérieux, France) in identifying strains of Streptococcus mutans was studied. Of 160 strains assayed, 72.5% were confirmed to be Streptococcus mutans; the remainder were identified as other species of streptocci (Streptococcus bovis, Streptococcus uberis, Streptococcus anginosus, Streptococcus sanguis I and II, Streptococcus intermedius, and Streptococcus constellatus).

Bacterial Typing Techniques↗
PubMed1995

Expansion of the seizure monitoring program. A collaborative approach.

This article discusses an interdisciplinary total quality management (TQM) project that planned for the expansion of the seizure monitoring program on a neuroscience unit. The processes of education, bed management, and patient care were evaluated by a TQM group of staff nurses, unit leader, attending physicians, clinical nurse specialist, and technicians. Each participant identified actual and potential problems and their effects on the participant's area of care.

Academic Medical Centers↗