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Biomedical subjects

L A Garcia

Publications and source records attributed to L A Garcia.

At least 19 recordsLinked to original sources
PubMed2006

Avascular necrosis of the pisiform.

Avascular necrosis of the pisiform bone is a very rare condition. This paper reports a case and discusses this pathology and its diagnosis.

Female↗
PubMed2004

The Philippine Male Aging Survey.

The aging male is fast becoming a global concern. The problem is predicted to become a major health issue that should be addressed immediately in order to prevent disability, morbidity, and, more importantly, mortality. As part of its commitment to increase awareness and create interest in the care of Filipino aging males, The Philippine Society for the Study of the Aging Male Foundation, Inc. (PhiSSAM), a multi-specialty society established in 2000, embarked on a survey among Filipino physicians to determine their knowledge, attitudes, and practices regarding male aging. Results showed that the majority of doctors (about 87%) thought that men may experience andropause. Most would diagnose patients based on symptoms alone, while only 20-30% used testosterone levels to make a diagnosis of andropause. Decreased libido and less strong erections were the symptoms very closely associated with low testosterone. Of those doctors responding, 89% agreed that andropause can affect the quality of a man's life as much as menopause can affect a female; only 38% had already prescribed/instituted treatment for andropause. Of the 62% non-prescribers, 58% said they were either very likely or fairly likely to institute treatment in the future if there were more clinical trials, more medical information, and more information on drugs. Major concerns on testosterone replacement therapy included prostate cancer, benign prostatic hypertrophy, and heart disease. The findings in this pilot survey indicate a need among the doctors in the Philippines for education about andropause and the available treatments.

Aged↗
PubMed2001

Risk factors for gallstone disease in the laparoscopic era.

BACKGROUND: The risk factors for gallstone disease are well known, but they have not been updated to take the development of better ultrasound technology and the advent of laparoscopic surgery into consideration. METHODS: We compared two groups of patients who underwent ultrasound-one group (n = 100) who underwent cholecystectomy after ultrasound revealed the presence of gallstones and a control group (n = 107) in whom no gallstones were shown on ultrasound. RESULTS: Seven patients in the control group refused to participate in the study; otherwise, the groups are sequential. Age in the surgery group was 51 years (+/- 16) vs 50 (+/- 16) for the control group. The percentage of female patients was 59% and 52%, respectively (p = ns). Body mass index was 32 (+/- 8) and 28 (+/- 6), respectively (p = 0.013). Parity > 2 was 0.49% and 0.37%, respectively (p = 0.000001). The number who breast-fed at least one child was 17 (24%) and eight (12%), respectively (p = 0.03). Oral contraceptive use was 37 (52%) and 17 (22%), respectively (p = 0.0005). Primary relatives who had had gallbladder surgery was 0.68 (+/- 1) and 0.35 (+/- 0.6), respectively (p = 0.02). CONCLUSION: Body mass index, breast-feeding, oral contraceptives, parity > 2, and family history were found to be risk factors for gallstone disease. Age and female sex were not, probably due to selection bias.

Body Mass Index↗
PubMed2001

In vivo assessment of stent recoil in normal porcine arteries: evaluation of contemporary stent designs.

Acute stent recoil has been observed following balloon deflation in normal and diseased coronary arteries, and the magnitude varies by stent design. We sought to evaluate acute stent recoil in five new stents. Twenty-five stents (four Crown, five Nir Conformer Royale, five Crossflex, five SupraG, and six GFX) were implanted in six Yorkshire pigs. All stents were expanded using a noncompliant balloon (balloon:artery ratio 1.2:1.0). Continuous ultrasound imaging was performed during stepwise balloon inflation and deflation using a 0.018" imaging core. Maximum cross-section areas (CSA) and minimal luminal diameter (MLD) were measured at 12 atm and immediately following balloon deflation. Maximum stent CSA matched expected balloon CSA. Area and diameter recoil were calculated as 1 - (CSAdeflation/CSAmax) and 1 - (MLDdeflation/MLDmax), respectively. Upon deflation, all stents showed recoil from maximal CSA. Area recoil was significantly lower for slotted-tube stents than modular stents (12.6% +/- 1.6% vs. 23.2 +/- 3.5%; P < 0.05). In compliant, nonatherosclerotic porcine coronary arteries, acute stent recoil for the four slotted-tube designs ranged from 8.4% to 18.0% by area. The modular stent tested was associated with significantly greater acute recoil than the slotted-tube stents.

Animals↗
PubMed2000

Interactions between CPR and defibrillation waveforms: effect on resumption of a perfusing rhythm after defibrillation.

BACKGROUND: Cardiopulmonary resuscitation (CPR) improves survival from cardiac arrest. The interactions between CPR and the new biphasic (BiP) defibrillation waveforms have not been defined. Our purpose was to compare the effect of CPR versus no CPR during BiP and damped sinusoidal (DS) shocks on the termination of ventricular fibrillation (VF) and the resumption of a perfusing rhythm. METHODS: We studied 20 pigs; VF was induced electrically and allowed to persist for 6 min. During VF episodes each pig received (in random order): (a) 6 min of full CPR (continuous ventilation and closed chest mechanical compression (Thumper, Michigan Instruments)) followed by DS defibrillation at 100 J; (b) no CPR, DS defibrillation; (c) 6 min of full CPR and BiP defibrillation at 100 J; and (d) no CPR, BiP defibrillation. RESULTS: BiP shocks with CPR terminated VF in 83% of attempts versus 45% without CPR (15/18 and 5/11 respectively, P<0.05). DS shocks with CPR were successful in terminating VF in 53% of attempts; DS shocks without CPR were successful in 44% (8/15 and 7/16, respectively, P=NS). No animal achieved a perfusing rhythm after shocks of either waveform if CPR did not precede the shocks during the 6-min VF period, whereas if CPR was administered during VF 46% (11/24) of the combined BiP/DS shocks restored a perfusing rhythm (P<0.01). CONCLUSION: In this experimental long duration VF model, CPR was essential for a perfusing rhythm after termination of VF by shocks with either waveform. CPR facilitated the termination of VF and resumption of a perfusing rhythm after biphasic waveform defibrillation but not after damped sinusoidal waveform defibrillation.

Animals↗
PubMed1999

Comparison of Bacillus subtilis and Serratia marcescens as protease producers under different operating conditions.

Two microorganisms, Bacillus subtilis and Serratia marcescens, have been selected in order to assess their ability to produce proteases. First, their performances have been studied using three media providing different levels of the main nutrients (complex, semi-defined and defined). The optimal absolute production was obtained in the complex media, while maximum protease activity per cell weight appeared in defined medium for Bacillus and in semi-defined and complex media for Serratia. Then, the effects of applying different environmental conditions to the cells were studied. The two microorganisms were immobilised in calcium alginate beads, protease production by these systems was assessed in the previously tested culture media, and the performances in free and immobilized operating conditions were compared. The richest medium seemed to be the best one in terms of absolute protease production, although the use of semi-defined or defined media could be considered more appropriate, in order to minimise growth of cells leaked from the support, and therefore downstream processing cost. Productivity was slightly higher in free cultures than in immobilized cultures, and retention of enzyme within the alginate beads was detected in the latter, indicating the occurrence of diffusional limitations. In all the cases studied, Serratia marcescens appeared as a better protease producer than B. subtilis, in terms of absolute production. This fact could be related to the different cell growth levels observed for the two microorganisms.

Journal Article↗
PubMed1999

Captopril lowers coronary venous free radical concentration after direct current cardiac shocks.

STUDY OBJECTIVES: Direct current (DC) shocks to the heart cause morphologic and functional myocardial damage. Previous studies have suggested that acute DC shock injury is free radical mediated and that the administration of antioxidant enzymes superoxide dismutase and catalase can reduce the level of DC shock-induced free radicals. Angiotensin-converting enzyme (ACE) inhibitors are clinically used drugs that may scavenge free radicals or reduce free radical generation. The objective of our study was to determine whether the ACE inhibitor captopril lowers free radicals after DC shocks. DESIGN: In six open-chest dogs, we administered 100-J DC shocks to the epicardium, before and after administration of captopril, 3 mg/kg. We used electron paramagnetic resonance measurements of arterial and coronary venous ascorbate free radical (AFR) as a real-time marker of free radical generation (total oxidative flux). MEASUREMENTS AND RESULTS: Captopril resulted in a significant lowering of coronary venous AFR concentration: the peak rise in AFR after 100-J shocks was 17.3+/-3.4% (mean +/- SEM before captopril vs. 3.2+/-4.0% after captopril; p<0.05). CONCLUSIONS: Captopril lowers coronary venous AFR concentration after high-energy epicardial shocks.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1999

Rheolytic thrombectomy with the Possis AngioJet: technical considerations and initial clinical experience.

Percutaneous revascularization of thrombus-containing lesions has an increased incidence of adverse events such as abrupt vessel closure, periprocedural myocardial infarction and death. Various pharmacologic and mechanical approaches have demonstrated modest angiographic success with significant periprocedural complications. The AngioJet (Possis Medical, Inc., Minneapolis, Minnesota) is a dual lumen catheter that uses the principle of rheolytic thrombectomy to remove unorganized thrombus. A previously unreported scoring system based on clinical and angiographic data may help to select patients most likely to benefit from AngioJet treatment. When compared with urokinase in the randomized VeGAS 2 Trial, AngioJet therapy yields greater angiographic success with a lower incidence of 30-day major adverse events. Technical considerations and complications are reviewed in detail.

Catheterization↗
PubMed1998

Transthoracic defibrillation: does electrode adhesive pad position alter transthoracic impedance?

Successful termination of ventricular fibrillation by transthoracic shocks is dependent on achieving adequate current flow, which in turn is governed by transthoracic impedance (TTI). The American Heart Association (AHA) Advanced Cardiac Life Support textbook recommends three electrode positions for defibrillation: (1) anterior-apex, (2) apex-posterior and (3) anterior-posterior. However, there are few data available comparing TTI of these positions. To study this, we applied large (78 cm2) self-adhesive monitor-defibrillator pads to 20 subjects (ten male, ten female, ages 21-79) and measured TTI using a validated test-pulse technique which does not require actual shocks. We performed two studies. In Study 1 (all 20 subjects) the electrode pads were applied in the three positions recommended by the AHA, with the posterior electrode placed in the right infrascapular location. All TTI measurements were made at end-expiration and body surface area (BSA) was recorded. The results (TTI, omega, mean +/- S.D.) for the respective positions were the following: anterior-apex, 82.0+/-24.7; apex-posterior, 71.2+/-23.5; anterior-posterior, 77.0+/-24.7 (P NS). In Study 2 (six subjects) we compared the effect of right vs. left infrascapular posterior electrode placement (TTI, omega): apex-right infrascapular (RIS), 76.8+/-18.4; apex-left infrascapular (LIS), 72.1+/-18.7; anterior-RIS, 72.5+/-19.4; anterior-LIS, 71.6+/-18.6 (P NS). Correlation of TTI (anterior-apex placement) with BSA: TTI = 15.9 (BSA) + 46.7, r = 0.60, P < 0.01; the correlations of TTI and BSA were similar in the other two electrode positions. Thus, the three AHA-recommended electrode positions for transthoracic defibrillation have equivalent and acceptable TTIs; current flow should be similar using any of these positions. Furthermore, the posterior electrode may be placed in either the right or the left infrascapular position without affecting TTI. TTI is related to BSA in any of the three recommended positions; patients with high BSA and TTI may require higher energy selection to achieve defibrillation.

Adult↗
PubMed1998

Magnesium reduces free radicals in an in vivo coronary occlusion-reperfusion model.

OBJECTIVE: This study demonstrated that magnesium (Mg) reduces free radicals after a brief coronary occlusion-reperfusion sequence. BACKGROUND: Magnesium has been shown to reduce infarct size in patients with acute myocardial infarction. We hypothesized that this action of Mg occurs through its action on free radicals. METHODS: Eighteen mongrel dogs were studied (nine control, nine receiving Mg). Catheters were placed into the coronary sinus for continuous blood withdrawal. A Varian E-4 electron paramagnetic resonance spectrometer was used to monitor the ascorbate free radical (AFR) signal in the coronary sinus blood; AFR is a measure of total oxidative stress. Occlusion of the left anterior descending coronary artery for 20 min was followed by reperfusion. The study animals received 4 g Mg intravenously starting at 15 min of occlusion (5 min before reperfusion) and continuing during reperfusion. RESULTS: Results are presented as percent change from baseline +/- SEM. Magnesium blunted the peak AFR increase: at 4 min of reperfusion there was a 4.7 +/- 3.3% increase in AFR signal in the dogs receiving Mg versus an 18.2 +/- 3.3% increase in the control animals (p < 0.05). Total radical flux was reduced during reperfusion by 53% in the Mg dogs compared with controls (p < 0.05). CONCLUSIONS: Magnesium attenuates AFR increase after an occlusion-reperfusion sequence. To our knowledge this is the first in vivo real-time demonstration of Mg's impact on free radicals.

Animals↗
PubMed1990

Auxotrophic mutants of Crithidia fasciculata.

In pursuance of genetic studies, after exposure to ethylmethanesulfonate, 11 auxotrophic mutants of Crithidia fasciculata were cloned. Three proved uracil dependent; 3 serine dependent; and the remainder have not had their auxotrophy defined.

Animals↗
PubMed1984

Fusion of small unilamellar vesicles induced by a serum albumin fragment of molecular weight 9000.

A peptide (P-9) comprising amino acids 307 to 385 of bovine serum albumin induced the fusion of small unilamellar vesicles of phosphatidylcholine at low pH. Upon acidification P-9 exhibited a ultraviolet differential spectrum characteristic of hydrophilic exposure of chromophores. This conformational change, and the structure of P-9 composed of three amphiphilic helixes , suggested a general working hypothesis for the description of protein-induced membrane fusion.

Animals↗
PubMed1983

Fusion of small unilamellar vesicles induced by bovine serum albumin fragments.

The limited pepsin proteolysis products of bovine serum albumin, fragment A (residues 307-586) and fragment B (residues 1-306), induced the fusion of small unilamellar vesicles of egg phosphatidyl choline at concentrations near 5 microM. Fusion was demonstrated and analyzed on the basis of: a) time-dependent changes in absorbance; b) dilution of the fluorescent label 2-(10-(1-pyrene)decanoyl) phosphatidyl choline, incorporated into a small percentage of the vesicles, as measured by the decrease in the excimer to monomer (E/M) ratio; c) increase of the average hydrodynamic radius of the liposomes, estimated by Sepharose 4B filtration, and d) the strict inverse relationship between the size of the liposomes and their E/M ratios. Albumin fragment B, like albumin, induced the formation of large aggregates in which rapid cooperative fusion produced vesicles having a large hydrodynamic radius. Fragment A did not produce large aggregates and the initial fusion products exhibited a hydrodynamic radius. Fragment A did not produce large aggregates and the initial fusion products exhibited a hydrodynamic radius smaller than those obtained with fragment B. Albumin and fragments A and B are fusogenic only at pH below 4.0. These data discussed in terms of a general model for a signal-dependent protein-induced membrane fusion.

Chromatography, Gel↗