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Biomedical subjects

J Torres

Publications and source records attributed to J Torres.

At least 127 records · Page 7Linked to original sources
PubMed1996

Healing response of the canine prostate to Nd:YAG laser radiation.

The objective of the study was to characterize the healing response of the canine prostate to laser thermal injury. The study included 20 canine prostates that underwent transurethral laser radiation. The prostates were retrieved 1 hr after laser radiation in 7 dogs (acute group), and from 3 days to 9 weeks in 13 dogs (chronic group). Two distinct features were observed. First, reepithelialization of the prostate urethra resulted from mobilization of proliferating epithelial cells from acinar and ductal prostatic epithelium into the cavity surface, and not from the edges of the wound at the bladder neck. Squamous cell metaplasia was a prominent feature of reepithelialization. Second, the healing process in the canine prostate was relatively unimpeded. The large glandular component provided abundant germinal epithelial growth, and the absence of stromal elements allowed for complete sloughing of necrotic tissue without residual eschars. Further, the lesions in the chronic group had a tendency to be larger than those in the acute group, suggesting that extended delayed necrosis may occur at deep prostatic tissue layers.

Animals↗
PubMed1996

Community outbreak of acute respiratory infection by Mycoplasma pneumoniae.

We present the results of the investigation of an epidemic outbreak of Mycoplasma pneumoniae infection which affected 95 schoolchildren from certain village in Catalonia. The investigation took an epidemiological, clinical and microbiological approach, detecting by capture enzyme-immunoassay technique the presence of IgM antibodies against M. pneumoniae. All cases occurred over a 9 week period. The attack rate in children under five was 18% and 8.2% in those from 5-14 years. The age mean and standard deviation of the cases was 5.2 +/- 3.5 years, the range being from 9 months to 14 years. Cough was the most common clinical manifestation (87.4%), followed by fever (67.4%), asthenia (21.1%), abdominal pain (18.9%), vomiting (13.7%), earache (8.4%) and sore throat (6.3%). There was no significant difference in the distribution of symptoms according to age groups. IgM anti M. pneumoniae was positive in 36 (37.9%) of the samples analysed. Treatment chosen in most cases (90) was eritromicin and there was a correct evolution in all cases except for two clinical and radiological recurrences. Hospitalization was only necessary in 5 cases. The present findings are important to emphasize the high incidence of M. pneumoniae respiratory disease in children under 5, and suggests that with respiratory processes affecting very young children, a possible Mycoplasma pneumoniae infection should also be considered and the necessary action taken in the form of early and appropriate treatment.

Adolescent↗
PubMed1996

An extended x-ray absorption fine structure study of the high-affinity cation-binding site in the purple membrane.

The structure of the high-affinity cation-binding site of bacteriorhodopsin was studied using extended x-ray absorption fine structure techniques. The results obtained for Mn2+ in aqueous solution and for the complex BR-Mn2+ (1:1 molar ratio) show great similarities, suggesting that Mn2+, when bound to this site, is coordinated with six atoms of oxygen, forming an octahedral disposition. The interatomic distance between the atoms of oxygen and the Mn2+ was found to be 2.17 A for the complex BR-Mn2+, similar to Mn2+ in solution (2.15 A). In addition, the absence of any other peak at greater distances in the Fourier-transformed spectrum indicates that neither phosphorus nor sulphur atoms are present in the second coordination shell. This suggests that this binding site is located in the protein, discarding the proximity of lipid polar headgroups.

Binding Sites↗
PubMed1996

Analysis of conformational changes in bacteriorhodopsin upon retinal removal.

The conformation of bacterioopsin in the apomembrane has been studied by Fourier transform infrared spectroscopy. Resolution enhancement techniques and curve-fitting procedures have been used to determine the secondary structural components from the amide I region. Bacterioopsin contains about 54% helicoidal structure (alpha I and alpha II helices + 3(10) turns), 21% sheets, 16% reverse turns, and 9% unordered structure. Thus, after retinal removal, all of the secondary structural types of bacteriorhodopsin remain present, and only slight quantitative differences appear. On the other hand, H/D exchange studies show that there is a higher degree of exchange for reverse turns and protonated carboxylic lateral chains in bacterioopsin as compared to bacteriorhodopsin. This gives further support to the idea of a more open tertiary structure of bacterioopsin, and to the consideration of the retinal molecule as an important element in complementing the interhelical interactions in bacteriorhodopsin folding.

Bacteriorhodopsins↗
PubMed1996

In-vitro antifungal activity of sertaconazole, bifonazole, ketoconazole, and miconazole against yeasts of the Candida genus.

The in-vitro antifungal activity of sertaconazole against 110 strains of Candida yeasts (50 Candida albicans, 15 Candida glabrata, 2 Candida guilliermodii, 8 Candida krusei, 1 Candida kefyr, 8 Candida parapsilosis and 26 Candida tropicalis) was assessed in comparison with bifonazole, ketoconazole, econazole and miconazole. The majority of the strains were clinical isolates; some reference strains were included. A commercial agar diffusion method (NeoSensitabs, Rosco, Taastrup, Denmark) in Shadomy's modified medium pH 7 was used. Using the manufacturer's criteria, 86.4% of the strains were classified as "sensitive" to sertaconazole. The only strain classified as "resistant" to sertaconazole was the control reference strain of C. albicans. The remaining strains were classified as "moderately sensitive". The sensitivity/resistance percentages for the other antifungals tested were 75.5/1.8 for ketoconazole, 71.8/2.7 for miconazole, 63.7/13.6 for econazole, and 59.1/5.5 for bifonazole. Sertaconazole showed a higher antifungal activity than that of the other antimycotics, tested in vitro which was statistically significant (P < 0.001), as well as a lower resistance rate than that of econazole, bifonazole and ketoconazole.

Antifungal Agents↗
PubMed1996

[Toxic megacolon secondary to ischemic colitis. Report of a case].

We report a 67 years old male that consulted due to bloody diarrhea of several months of evolution and emaciation. According to endoscopic and radiological findings, the diagnosis of severe ulcerative colitis was made. Fifteen days after admission, the patient was subjected to an emergency total colectomy due to a toxic megacolon. The pathological study showed an ischemic colitis with extensive longitudinal ulcers in the antimesenteric border, presence of granulation tissue with inflammation and transmural fibrosis. Intestinal transit was reconstituted six months later and after 12 months of follow up the patient is in good conditions.

Aged↗
PubMed1996

On Physaloptera sibirica Petrow et Gorbunow, 1931 (Nematoda: Physalopteridae) parasitizing Iberian mammals.

Faunistic and morphological study of Physaloptera sibirica PETROW et GORBUNOW, 1931 (Nematoda: Physalopteridae), a nematode isolated in Spain from three mammal species: red fox, Vulpes vulpes (LINNAEUS, 1758) (Carnivora: Canidae), eurasian badger, Meles meles (LINNAEUS, 1758) (Carnivora: Mustelidae), and garden dormouse, Eliomys quercinus (LINNAEUS, 1766) (Rodentia: Myoxidae) in the Iberian Peninsula. Morphological features of cephalic and caudal regions of males are presented for the first time by SEM (scanning electron microscopy).

Animals↗
PubMed1995

Conformational changes in bacteriorhodopsin associated with protein-protein interactions: a functional alpha I-alpha II helix switch?

Fourier transform infrared spectra of bacteriorhodopsin samples were obtained in conditions in which the aggregation state of the protein (i.e., monomeric or trimeric) was modified by different treatments. Two approaches were followed: (1) renaturation of bacteriorhodopsin starting from bacterioopsin dissolved in SDS and (2) reconstitution of bacterioopsin in Halobacterium lipid liposomes at two different lipid/protein ratios. Concomitant with the gradual recovery of the native interactions between transmembrane helices, we observed clear and gradual changes in the infrared absorption spectra in the amide I band and also in the band at 1741 cm-1. These processes were found to be compatible with the two-state oligomerization model. The whole set of experiments shows that the band at 1665 cm-1 in the deconvoluted spectra appears only when monomers interact forming trimers, even when the lattice is not present. This implies that the trimeric organization of bacteriorhodopsin is responsible for the unique features described in the amide I of purple membrane. The spectroscopic changes detected can be attributed to changes in secondary structure compatible with the interconversion of alpha I and alpha II helices. However, the exact nature and functional relevance of these changes is still unknown.

Amino Acids, Dicarboxylic↗
PubMed1995

Inhibition of cytochrome c oxidase in turnover by nitric oxide: mechanism and implications for control of respiration.

Binding of nitric oxide (NO) to isolated cytochrome c oxidase in turnover was investigated by static and kinetic spectroscopic methods. These studies indicate that cytochrome c oxidase rapidly binds NO when the enzyme enters turnover. Our results show that NO binds to ferrocytochrome a3, competing with oxygen for this binding site. However, the main features of the binding process, in particular the rapid onset of inhibition, cannot be fully explained on this basis. We suggest, therefore, that there is a second binding site for NO, which has lower affinity but nevertheless plays an important role in the inhibitory process. A likely possibility is that CuB+ constitutes this second binding site. The fast onset of inhibition observed in the presence of NO, along with the dependence on the oxygen concentration, suggests that under physiological conditions, where the oxygen concentration is low, nanomolar concentrations of NO can effectively act as a regulator of the mitochondrial respiratory chain.

Animals↗
PubMed1995

[Predictive factors of surgical infection in heart surgery].

BACKGROUND: Deep infection of the surgical site in cardiac surgery may lead to very severe complications. There is controversy as to the importance which different factors may have in the incidence of this complication. The aim of this study was to determine the importance of determined factors on the risk of deep infection of the surgical site. METHODS: A retrospective study of 1,127 patients submitted to cardiac surgery from 1989 to 1991 was performed. The factors associated to the development of deep surgical infection were determined by univariant analysis. A multiple logistic regression model was designed to identify the factors independently associated to the risk of infection. The morbidity of surgical infection attributable to prolonged preoperative stay was calculated. RESULTS: Of the numerous factors associated to risk of surgical site infection on univariant analysis, only five were independently associated to risk of infection on multivariant analysis: prolonged preoperative stay (OR = 2.4 [1.1-5.5]), dirty surgery (OR = 3.2 [1.0-9.9]), length of the intervention (OR [every hour] = 1.5 [1.2-2.0]), diabetes mellitus or chronic obstructive pulmonary disease (OR = 2.6 [1.2-5.6]) and functional grade according to the New York Heart Association (OR = 3.4 [1.5-7.7]). The proportion of deep infection attributable to prolonged preoperative stay was 41.8% (4.0-58.2). CONCLUSIONS: The incidence of deep surgical infection may be decreased with a reduction, whenever possible, of the length of surgical intervention and preoperative stay.

Analysis of Variance↗
PubMed1995

Spectroscopic studies of bacteriorhodopsin fragments dissolved in organic solution.

Fourier transform infrared and UV fourth-derivative spectroscopies were used to study the secondary structure of bacteriorhodopsin and its chymotryptic and one of the sodium borohydride fragments dissolved in chloroform-methanol (1:1, v/v), 0.1 M LiClO4. The C1 fragment (helices C, D, E, F, and G) showed an alpha-helical content of about 53%, whereas C2 (helices A and B) had about 60%, and B2 (helices F and G) about 65% alpha-helix. The infrared main band indicated differences in alpha-helical properties between these fragments. These techniques were also used to obtain information on the interactions among helices. According to the results obtained from the hydrogen/deuterium exchange kinetics, about 40% of the amide protons of C2 are particularly protected against exchange, whereas for the C1 fragment this process is unexpectedly fast. UV fourth-derivative spectra of these samples were used to obtain information about the environment of Trp side chains. The results showed that the Trp residues of C2 are more shielded from the solvent than those of C1 or B2. The results of this work indicate that the specific interactions existing between the transmembrane segments induce different types of helical conformations in native bacteriorhodopsin.

Bacteriorhodopsins↗
PubMed1995

Randomized clinical trial comparing low power-slow heating versus high power-rapid heating noncontact neodymium:yttrium-aluminum-garnet laser regimens for the treatment of benign prostatic hyperplasia.

OBJECTIVES: To evaluate and compare the safety and effectiveness of two noncontact laser regimens for the treatment of human benign prostatic hyperplasia (BPH), and to assess the impact of the spatial distribution of the laser-induced lesions on treatment outcome. METHODS: This was a prospective, double-blind, randomized study that included 29 patients with BPH (both the patients and the study physician assistant in charge of the follow-up evaluation were blinded to the treatment rendered). The patients were randomized to receive either a 15 W for 180 s (15 patients) or 50 W for 60 s (14 patients) laser regimen (powers measured at the fiber tip). There were two study phases for each treatment group: the irradiated sites were not overlapping during the first phase (lesions 1.5 cm apart), and were overlapping during the second phase (lesion less than 1.0 cm apart). RESULTS: Morbidity was minimal in both groups. At 1 year of follow-up, there was significant improvement of the American Urological Association-7 symptom score, the peak urinary flow rate, and the postvoid residual in both treatment groups. These improvements were not statistically significantly different regardless of time or the phase of the study for the two treatment groups. There were 3 treatment failures, 2 of whom were later successfully re-treated with larger amounts of laser energy. Furthermore, the peak flows in the second phase of the study were statistically significantly higher than those in the first phase of the study, regardless of the treatment group. CONCLUSIONS: Our results suggest that both the 15 W for 180 s and the 50 W for 60 s are equally safe and effective treatments for BPH. Perhaps more importantly, they also suggest that the spatial distribution of lesions and overlapping of treated (irradiated) sites has significant impact on treatment outcome.

Aged↗
PubMed1995

Antibodies to the putative SIV infection-enhancing domain diminish beneficial effects of an SIV gp160 vaccine in rhesus macaques.

OBJECTIVE: To demonstrate that antibodies against amino acids (aa) 603-622 of the SIV gp41 transmembrane glycoprotein enhance infection of SIV in vivo. DESIGN: A synthetic peptide derived from aa 603-622 of SIVmac251 gp41 was synthesized and tested for immunogenicity in rabbits and SIV-infected rhesus macaques. Next, SIV-naive animals were immunized with either a recombinant vaccinia virus expressing the SIV gp160 envelope glycoprotein (VVrgp160) and boosted three times with aa 603-622 (group 1, four animals), wild-type vaccinia virus and boosted with aa 603-622 (group 2, two animals), or VVrgp160 followed by three doses of an irrelevant peptide (group 3, two animals). Animals were challenged with SIVmac251. RESULTS: Peptide aa 603-622 was immunogenic in rabbits. SIV-infected rhesus monkeys immunized with the peptide developed two-three log increases in antibodies to this peptide and antibodies that could enhance SIV infection in vitro. SIV-naive rhesus macaques in group 1 had higher levels of antibody to the peptide by enzyme-linked immunosorbent assay and higher levels of enhancing antibodies at the time of SIV challenge than the animals in groups 2 or 3. Following challenge with SIVmac251 the group 1 animals had detectable p27 antigen longer than animals in group 2 and 3 and died of simian AIDS before the respective animals in the two control groups (P < 0.05 by log-rank test). CONCLUSIONS: aa 603-622 of SIV gp41, like aa 579-613 of HIV gp41, can stimulate production of antibodies that enhance SIV and HIV infection in vitro. Furthermore, immunization with this peptide suppressed beneficial effects of a gp160 vaccine and appeared to enhance SIV infection in vivo.

Animals↗
PubMed1995

Levodopa does not aggravate postural tremor in Parkinson's disease.

Characterization of postural tremor in Parkinson's disease (PD) is incomplete. It was suggested to be an exaggerated physiological tremor and to be enhanced by the action of levodopa. We compared the magnitude of postural tremor to the magnitude of rest tremor and to plasma levodopa levels in 20 PD patients, 10 with stable motor response to oral levodopa, and 10 with the wearing-off phenomenon. Tremor assessment included motor scores of the Unified Parkinson's Disease Rating Scale and accelerometric measurements. Accelerometric data showed that the absolute power of both rest and postural basal dominant tremor frequencies significantly diminished with the increase in plasma levodopa levels and increased with their decrease. Tremor frequencies were also significantly changed by levodopa, which slowed rest tremor and increased postural tremor dominant frequency. This latter, however, did not reach the 8- to 12-Hz frequency band said to be typical of exaggerated physiological tremor. No significant differences between groups were found in their tremor response to levodopa. This study shows that the net postural tremor exhibited by PD patients is improved by levodopa, that levodopa does not augment tremor in the 8- to 12-Hz range, and that this effect is independent of the patient's motor response pattern of oral levodopa.

Aged↗