Biomedical subjects

G Villanueva

Publications and source records attributed to G Villanueva.

14 recordsLinked to original sources

PubMed2006

The utility of an automated electronic system to monitor and audit transfusion practice.

BACKGROUND AND OBJECTIVES: Transfusion laboratories with transfusion committees have a responsibility to monitor transfusion practice and generate improvements in clinical decision-making and red cell usage. However, this can be problematic and expensive because data cannot be readily extracted from most laboratory information systems. To overcome this problem, we developed and introduced a system to electronically extract and collate extensive amounts of data from two laboratory information systems and to link it with ICD10 clinical codes in a new database using standard information technology. MATERIALS AND METHODS: Three data files were generated from two laboratory information systems, ULTRA (version 3.2) and TM, using standard information technology scripts. These were patient pre- and post-transfusion haemoglobin, blood group and antibody screen, and cross match and transfusion data. These data together with ICD10 codes for surgical cases were imported into an MS ACCESS database and linked by means of a unique laboratory number. Queries were then run to extract the relevant information and processed in Microsoft Excel for graphical presentation. We assessed the utility of this data extraction system to audit transfusion practice in a 600-bed adult tertiary hospital over an 18-month period. RESULTS: A total of 52 MB of data were extracted from the two laboratory information systems for the 18-month period and together with 2.0 MB theatre ICD10 data enabled case-specific transfusion information to be generated. The audit evaluated 15,992 blood group and antibody screens, 25,344 cross-matched red cell units and 15,455 transfused red cell units. Data evaluated included cross-matched to transfusion ratios and pre- and post-transfusion haemoglobin levels for a range of clinical diagnoses. Data showed significant differences between clinical units and by ICD10 code. CONCLUSION: This method to electronically extract large amounts of data and linkage with clinical databases has provided a powerful and sustainable tool for monitoring transfusion practice. It has been successfully used to identify areas requiring education, training and clinical guidance and allows for comparison with national haemoglobin-based transfusion guidelines.

Adult↗

PubMed2000

Efficacy of preoperative versus postoperative ketorolac tromethamine 0.5% in reducing inflammation after cataract surgery.

PURPOSE: To compare the efficacy of 30 minute preoperative versus 1 day postoperative administration of ketorolac tromethamine 0.5% ophthalmic solution (Acular) in reducing anterior chamber inflammation after cataract surgery. SETTING: The Hermann Eye Center, The University of Texas Health Science Center-Houston, Texas, USA. METHODS: Fifty eyes of 48 consecutive patients scheduled for phacoemulsification with intraocular lens implantation were included. Before surgery, patients were randomly assigned to start the study drug 30 minutes preoperatively or 1 day postoperatively. No other antiinflammatory agents were used intraoperatively or postoperatively. Main outcome measures were flare and cell counts. RESULTS: Preoperative and postoperative flare and cell counts did not differ significantly between the 2 treatment groups at any time. Both groups showed significant increases in flare (P =.0001) and cells (P =.0001) 1 day postoperatively. Flare and cells returned to baseline levels by day 28 in both groups. There was no significant difference at any time between the 2 groups in the change from the preoperative level of inflammation. CONCLUSIONS: There was no difference between administering ketorolac 30 minutes preoperatively versus 1 day postoperatively in reducing inflammation.

Adult↗

PubMed1999

Ondansetron/promethazine combination or promethazine alone reduces nausea and vomiting after middle ear surgery.

STUDY OBJECTIVES: To determine the incidence of postoperative nausea and vomiting when a combination of ondansetron and promethazine is given prophylactically, and to ascertain the effect of postoperative nausea and vomiting on recovery room duration and patient satisfaction. DESIGN: Prospective, randomized, placebo-controlled, double-blind study. SETTING: University-affiliated tertiary-care hospital. PATIENTS: 87 ASA physical status I and II adult patients scheduled for middle ear surgery. INTERVENTIONS: Patients were randomly assigned to receive one of the following interventions intravenously: ondansetron 4 mg (Group 1), promethazine 25 mg (Group 2), ondansetron 2 mg plus promethazine 12.5 mg (Group 3, combination), or placebo (Group 4). MEASUREMENTS AND MAIN RESULTS: Independent, study blinded observers recorded complaints of nausea and number of episodes of vomiting for 24 hours following the patient's first response to commands. All patients were contacted the day after discharge to inquire about nausea and vomiting. The awakening time, postanesthesia care unit and day surgery unit durations, opioid use, and side effects were recorded. At the end of the 24-hour period, the study blinded observers asked patients for an overall assessment of their global anesthesia experience using an 11-point scale. During the 24-hour period, the incidence of postoperative nausea and vomiting was reduced from 74% (placebo) to 39% (promethazine; p = 0.03) and 29% (combination; p = 0.003). Compared with placebo, the severity of vomiting was significantly less in the combination group (p = 0.04). The number of very satisfied patients correlated negatively with the incidence of postoperative nausea and vomiting (p < 0.0001) and with the severity of vomiting (p = 0.003). CONCLUSION: The prophylactic use of an antiemetic with middle ear surgery may reduce postoperative nausea and vomiting over 24 hours, and the ondansetron/promethazine combination or promethazine alone are cost-effective choices. Finally, the combination reduced significantly the severity of vomiting.

Adolescent↗

PubMed1999

N400 and lexical decisions: automatic or controlled processing?

OBJECTIVE: To investigate whether the N400 effect is sensitive to automatic or controlled processes. METHODS: Two experiments were performed. In one experiment, directly related word pairs were used. In the other experiment, mediated-related word pairs were used. In order to reduce controlled processes, each experiment consisted of 3 tasks: Low- and high-proportion of related pairs, and single presentation lexical decision task. RESULTS: In the first experiment, the amount of priming was equivalent for the 3 tasks. The N400 effect appeared in the high and low proportion of directly related words, but not in the single presentation task. In the second experiment, behavioral priming was also found in the 3 tasks. However, the N400 effect was observed only in the task with low proportion of related pairs. CONCLUSION: These results suggest that the N400 effect may be related to controlled processes.

Adult↗

PubMed1999

Consensual inflammation following ocular surgery.

PURPOSE: To determine whether a consensual inflammatory response occurs following unilateral phacoemulsification or trabeculectomy in humans. METHODS: Sixty patients undergoing phacoemulsification or primary trabeculectomy were included in the study. Some patients were randomly assigned to have a shield placed on the non-operated eye during surgery. The Kowa laser flare meter (FM-500) and laser cell counter (LC-500) (Kowa Electronics and Optics, Tokyo, Japan) were used to assess the inflammatory response in both eyes. Measurements were taken preoperatively and on postoperative days 1, 7 and 28. The regression analysis with random model effect was used to identify factors which may affect the change of flare and cells in the non-operated eye after surgery. Correlation was evaluated between the inflammatory responses of the paired eyes. A P<0.05 was considered statistically significant for all analyses. RESULTS: The flare and cells in the non-operated eye showed a small, but significant, increase on day 1 (mean flare increased 2.68 photons/ms from preoperative level with P<0.001 and mean cells increased 2.49 cells/0.5 mm3 from preoperative level with P<0.0001). At day 7 the amount of inflammation was still elevated (mean flare increased 0.41 photons/ms from preoperative level with P<0.001 and mean cells increased 0.63 cells/0.5 mm3 from preoperative level with P<0.001). By day 28, the amount of inflammation in the nonoperated eyes returned to preoperative levels. CONCLUSIONS: Subclinical inflammation occurs in the non-operated eye following phacoemulsification and trabeculectomy. The etiology of this finding has yet to be elucidated.

Adult↗

PubMed1999

Low-dose postoperative transconjunctival application of mitomycin C in rabbit trabeculectomy.

PURPOSE: Mitomycin C (MMC) is commonly administered during filtering surgery to enhance the success of the procedure. Unfortunately, the increased success rate is associated with complications, including late bleb leaks, endophthalmitis, and ciliary epithelial toxicity. The purpose of this study was to investigate a safe and effective dose regimen for MMC to reduce incidence of those complications. METHODS: Trabeculectomy was performed in 36 rabbits. MMC was applied only during surgery, only one day after surgery, or once daily after surgery for 3 days at lower concentrations. Balanced salt solution (BSS) was administered during surgery to one group as a placebo. The time to bleb failure was determined and the eyes were evaluated histopathologically. Success and toxicity were compared for the different treatment groups. RESULTS: The mean time until trabeculectomy failure was 2.83 days for the placebo group, 6.33 days with administration of MMC 0.5 mg/mL during surgery, 7.83 days with administration of MMC 0.5 mg/mL once after surgery, and 11, 9, and 4.83 days with administration of MMC 0.1 mg/mL, 0.05 mg/mL, or 0.025 mg/mL, respectively, once a day for 3 consecutive days. On electron microscopic examination of the ciliary epithelium, toxic effects were greatest with MMC concentrations of 0.5 mg/mL and were less with lower concentrations. CONCLUSION: The effect of MMC on trabeculectomy survival was dependent on both the concentration and the method of administration. Lower concentrations with multiple postoperative administrations were as effective as but caused less ciliary body toxicity than intraoperative administration of higher concentrations.

Alkylating Agents↗

PubMed1998

Reproducibility of the laser flare meter and laser cell counter in assessing anterior chamber inflammation following cataract surgery.

BACKGROUND AND OBJECTIVES: To determine the interobserver and intraobserver reproducibility of the laser flare meter and laser cell counter in assessing anterior chamber inflammation following cataract surgery. PATIENTS AND METHODS: Thirty-nine eyes with varied degrees of inflammation and 9 normal eyes were included in the study. Anterior chamber flare and cells were evaluated with the slit lamp and graded on a scale of 0 to 4+. The flare and cells were then measured three times each using the flare meter and cell counter by two different, experienced observers. The intraobserver reproducibilities were computed to evaluate repeatability of the instruments operated by the same observer. The first measurement taken by each observer was used to assess reproducibility between the two observers. RESULTS: The intraobserver reproducibility for overall flare was 0.995 for both observers. The intraobserver reproducibility for overall cells was 0.996 for observer 1 and 0.991 for observer 2. The overall interobserver reproducibility was 0.994 for flare and 0.988 for cells. The correlation between measurements and slit-lamp ratings was 0.78 for flare and 0.56 for cells. CONCLUSIONS: The intraobserver and interobserver reproducibilities were excellent, with good correlation to slit-lamp measurements. Reproducible results can be obtained using the laser flare meter and the laser cell counter. It is not known whether these results are applicable to other inflammatory processes with higher grades of flare and cells and with different protein and cell types.

Anterior Chamber↗

PubMed1998

A randomized double-masked trial comparing ketorolac tromethamine 0.5%, diclofenac sodium 0.1%, and prednisolone acetate 1% in reducing post-phacoemulsification flare and cells.

BACKGROUND AND OBJECTIVE: To compare the efficacy of ketorolac tromethamine 0.5%, diclofenac sodium 0.1%, and prednisolone acetate 1% in reducing flare and cells following cataract surgery. PATIENTS AND METHODS: Fifty-eight patients undergoing phacoemulsification with posterior chamber intraocular lens implantation were randomly selected to receive either ketorolac tromethamine 0.5%, diclofenac sodium 0.1%, or prednisolone acetate 1% following surgery. The treatment regimen was 1 drop 4 times a day for 1 week, then twice a day for the next 3 weeks. Flare, cells, and intraocular pressures (IOPs) were measured preoperatively and on postoperative days 1, 7, and 28. RESULTS: No statistically significant differences in either actual flare or cell counts or in change in flare or cell counts from baseline were detected among the three groups. No statistically significant differences in IOP or in change of IOP from preoperative measurements were detected. No medication-related complications were noted at any time. CONCLUSION: Ketorolac tromethamine 0.5% and diclofenac sodium 0.1% may be as effective and as safe as prednisolone acetate 1% in controlling inflammation following cataract extraction.

Adult↗

PubMed1997

Valve membrane adhesion as a cause of Ahmed glaucoma valve failure.

PURPOSE: The purpose of this study was to describe a possible mechanism of failure of the Ahmed glaucoma valve (AGV; New World Medical, Rancho Cucamonga, CA). METHOD: Two AGVS that failed to control intraocular pressure (IOP) were examined. In vivo examination consisted of unroofing the capsule surrounding the implant and injecting fluorescein-stained balanced salt solution into the tube. In one case the entire implant was removed and examined in vitro, and in the other case only the valve portion was removed. RESULT: No flow in either case extended beyond the valve. In both cases, the membrane valve system was found to be fused and could not be pulled apart. CONCLUSION: Failure of the AGV may occur due to adhesion of the valve membranes.

Anterior Chamber↗

PubMed1993

[Clinical and etiologic study of 90 cases of chronic diarrhea].

90 patients with chronic diarrhoea underwent this prospective study. They were seen in a private hospital of Lima during 1990 and 1991. According to a methodologic plan for determining sources and the diseases that originate chronic diarrhoea. In all patients hematologic, bioquimic, coprocultures, coproparasitologic exams were done, chest and intestinal transit X-rays. All underwent duodenal content culture. Colon X-ray in 25 cases; proctosigmoidoscopy in 14 and upper digestive endoscopy in 19 patients. Abdominal echography in 12 and TAC in 2 cases. The final results showed as determinant diseases for chronic diarrhoea, according to their frequency: enteroparasitosis (23.3%), functional digestive disorders (20.0%), intestinal bacterial overpopulation (15.5%) of unknown origin (8.8%), colon diverticulus (7.7%) proven and probably (5.5%), lactose intolerance (3.3%), diabetes mellitus (2.2%), and in one case (1.1%) the following: intestinal linfoma, pancreas malignancy, AIDS, colonic and deformation and megaloblastic anemia. The causes of chronic diarrhoea are several and multifactorals and in this study we prove the preeminence of the intestinal parasitosis, functional disorders and intestinal bacterial overpopulation and with less frequency other pathologies.

Adolescent↗

PubMed1990

[Phagocytic capacity of peritoneal exudate cells from rats immunized with a ribosomal preparation of Ty2 Salmonella typhi].

It was compared the activity of exudate peritoneal cells (EPC) obtained from CFW mice immunized either with Salmonella typhi Ty2 ribosomal fraction or whole-cell heat inactivated vaccine, both in comparison with EPC from sham-immunized. In the group which received ribosomal preparation, a subcutaneous dose equivalent to 100 micrograms of RNA in incomplete Freund's adjuvant (IFA) was initially used and 14 days after a booster of the same dose in IFA was given. A single dose of whole-cell heat inactivated vaccine, with 10(6) bacteria in IFA was employed subcutaneously in animals of the second group. EPC from controls and immunized mice were withdrawn at periods of 7, 11, 14, 18, 22, 25, 29 and 31 days after immunization and each sample was incubated in vitro in presence of live virulent non-opsonized S. typhi Ty2 in 1:200 cell-bacteria relation. Twenty four hours after cultivation, EPC bacterial capacity was determined after cell disruption and enumeration of survival bacteria were made through viable counts. Results have shown that EPC from mice immunized were more efficient in eliminating intracellular bacteria than those which came from sham-immunized animals. Also, it was found that EPC from mice immunized with ribosomal preparation were more efficient (maximum P = 0.005) than EPC from the mice which received killed whole bacteria.

Animals↗

PubMed1989

On the origin of the positive band in the far-ultraviolet circular dichroic spectrum of fibronectin.

The genesis of the positive bands in the far-ultraviolet circular dichroic spectra of human plasma fibronectin and its 31-kDa NH2-terminal heparin-binding fragment was studied. Spectra of ester derivatives of tyrosine, tryptophan, and phenylalanine and of model mixtures of these derivatives in which they are present in the same ratios as in the proteins indicate that all the aromatic side chains make substantial contributions to composite positive bands with maxima several nanometers below those of the proteins. In the presence of solvent perturbants such as polyethylene glycol and ethylene glycol, the bands of the model mixtures are red-shifted to the approximate positions they have in the spectra of the proteins. No additional red shift is seen with solvent perturbation of the proteins, suggesting that the conditions leading to this effect are satisfied within the proteins. A separate effect of solvent perturbation, an increase in amplitude of the positive band, occurs equally in solutions of free aromatic amino acid derivatives and in the proteins. This effect is used to estimate the relative accessibility of the chromophores of fibronectin and its fragment to different perturbants. The possible influence of protein secondary structure on the amplitude of the positive circular dichroic band is discussed.

Circular Dichroism↗

PubMed1988

Structural changes in the NH2-terminal domain of fibronectin upon interaction with heparin. Relationship to matrix-driven translocation.

The effects of heparin and various related polysaccharides on the circular dichroic spectra of fibronectin and its 31-kDa NH2-terminal tryptic fragment were studied. These effects were evaluated with respect to (i) spectral features of the native proteins that are sensitive to pH denaturation and breaking of disulfide bonds, (ii) sensitivity of spectral changes to Ca2+, and (iii) the fibronectin-dependent interfacial interaction known as "matrix-driven translocation." We found that native heparin causes an attenuation of the positive CD peak at 228 nm with both the intact protein and the fragment, and causes a small but reproducible red shift in the spectrum of the fragment. All of these changes are analogous to spectral changes seen with denaturation or reduction of the proteins. In contrast to the situation with the intact protein, the heparin-induced spectral changes in the fragment were abolished in the presence of 10 mM Ca2+. Desulfation of heparin lessened or destroyed its ability to induce these changes, and carboxymethylated heparin and dextran sulfate induced different kinds of spectral alterations. Fibronectin and heparin determinants required for the induction of the characteristic spectral shift of the NH2-terminal domain corresponded to those required for matrix-driven translocation, suggesting that the associated conformational change in fibronectin plays a role in this biophysical effect.

Affinity Labels↗

PubMed1979

Conformational changes accompanying the binding of antithrombin III to thrombin.

The conformational aspects of the binding of antithrombin III to thrombin were investigated by difference spectroscopy, circular dichroism, and optical rotatory dispersion. The CD and ORD studies indicate an increase of 6--8% in alpha-helix content at the expense of the beta structure, while the results from difference spectroscopy showed an increased exposure of approximately seven tyrosine residues. In the presence of heparin there is a slightly greater increase in helicity which is accompanied by exposure of an average of two tryptophan and one tyrosine residues. These spectral results indicate that the thrombin-antithrombin III complex formed in the presence of heparin differs in its conformation from that produced in its absence.

Antithrombin III↗