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Biomedical subjects

G Garcia

Publications and source records attributed to G Garcia.

At least 73 records · Page 4Linked to original sources
PubMed1996

Volume-mediated pulmonary responses in liver transplant candidates.

Pulmonary hypertension, defined as mean pulmonary artery pressure (mPAP) greater than or equal to 25 mmHg, is a recognized complication of hepatic dysfunction with portal hypertension and is considered a relative contraindication to liver transplantation. To characterize pulmonary hemodynamic responses in OLT candidates without pre-existing primary pulmonary hypertension, 22 consecutive patients referred for OLT at the Stanford University Hospital underwent prospective right heart catheterization with pressure determinations at baseline and following infusion of 11 crystalloid over 10 min. In addition, EKG, chest X-ray and transthoracic echocardiograms were performed as a part of the routine evaluation. Eleven non-cirrhotic patients served as controls. At baseline, 1/22 (4.5%) OLT patients had pulmonary hypertension while 9/22 (41%) developed pulmonary hypertension following volume infusion (p < 0.0001). In contrast, 0/11 controls manifested elevated pulmonary pressures at baseline or following volume challenge. OLT candidates were found to have significant increases in mean pulmonary pressure and capillary wedge pressure (PCWP) compared to controls, suggesting intravascular volume overload or left ventricular dysfunction as potential causes. OLT candidates who manifested volume-dependent pulmonary hypertension (a) had a 2-fold higher baseline PCWP, (b) currently smoked, and (c) had previously undergone portosystemic shunts. Aggregate analysis of EKG, echo and CXR for determination of volume-mediated pulmonary hypertension revealed a sensitivity of 25%, specificity of 75% and a positive predictive value of 40%. Preoperative identification of patients with a predisposition to manifesting elevated pulmonary pressures in the context of rapid volume infusion offers the potential for improved risk stratification and optimized clinical management.

Adult↗
PubMed1995

Effect of sulindac on sporadic colonic polyps.

BACKGROUND/AIMS: We sought to determine in a double-blinded, placebo-controlled study if the nonsteroidal anti-inflammatory drug sulindac causes regression of sporadic colonic polyps. The impetus for this study is the profound regressive effect of sulindac on polyps in familial adenomatous polyposis. METHODS: Asymptomatic patients undergoing routine screening flexible sigmoidoscopy were enrolled if they had polyps of < or = 1 cm in size. Of 162 patients screened, 22 patients were randomly enrolled to take 150 mg of sulindac twice daily, and 22 patients took a placebo. Treatment duration was 4 months and was followed by colonoscopy with removal of all polyps. RESULTS: Four patients were dropped from the study (sulindac group) due to urosepsis (1 patient), heartburn (2 patients), and anemia (1 patient). Compliance (determined by monthly pill counting), mean age, and the effect of sulindac vs. placebo on polyp regression or size were not statistically different in the two treatment groups. Analysis of our data indicated that there is only a 0.8% chance that the probability of polyp regression with sulindac is as large as 50%. CONCLUSIONS: Four months of treatment with sulindac does not result in a clinically significant regression of sporadic colonic polyps, although a small effect may not have been detected by the size of our study. Our data suggest that the biological response of sporadic and familial polyposis polyps to sulindac is different.

Aged↗
PubMed1995

Food-frequency questionnaire validation among Mexican-Americans: Starr County, Texas.

A food-frequency questionnaire (FFQ) for low-income Mexican-Americans in Starr County, Texas, was developed as part of an epidemiologic study of gallbladder disease during 1985 and 1986. The FFQ was developed from 7-day food records collected from the first sample. In the validity study, using the second sample, correlations between nutrients calculated from 3-day food records and the FFQ were 0.77, 0.76, and 0.61 for energy, total fat, and saturated fat, respectively. In the reliability study, using the third sample, for the 1-month interval between baseline and a repeat FFQ measurement correlations ranged from 0.90 for energy to 0.85 for total fat and for the 2-month interval they were 0.84 for energy and 0.70 for total fat. The high correlations are largely explained by the lack of diversity in the diets of Starr County individuals which facilitated the high agreement between the FFQ and the food records for estimates of energy, fats, and cholesterol.

Adult↗
PubMed1995

Orthotopic liver transplantation with selective use of venovenous bypass.

BACKGROUND: To determine the utility of selective use of venovenous bypass (VVB), an algorithm based upon hemodynamic criteria was instituted at Stanford University Medical Center: the bypass was used if the systolic blood pressure decreased below 100 mm Hg with a trial of caval and portal clamping. PATIENTS AND METHODS: Eleven consecutive patients underwent orthotopic liver transplantation (OLT) with use of VVB on a selective basis; using the hemodynamic exclusion criteria, none required VVB. A group of 20 patients undergoing OLT with VVB served as historical controls. RESULTS: Overall patient and graft survival were identical in both groups (75%). Avoidance of VVB decreased operative and warm ischemia time and decreased peak transaminase and total bilirubin values, but increased rates of intraoperative blood loss. However, the absolute numbers of blood products administered were not different between groups. CONCLUSION: Selective use of VVB for OLT does not incur increased morbidity or mortality. Potential advantages include cost savings with decreased operative and anesthetic time.

Adult↗
PubMed1995

Magnetic resonance imaging-derived parameter of portal flow predicts volume-mediated pulmonary hypertension in liver transplantation candidates.

BACKGROUND: Pulmonary hypertension is a source of perioperative mortality after orthotopic liver transplantation (OLT). The purpose of this study is to (1) characterize the pulmonary hemodynamic response in OLT candidates, and (2) determine whether portal flow index (PFI), a magnetic resonance imaging (MRI)-derived parameter, is a useful predictor of the pulmonary hemodynamic response. METHODS: Twenty-five consecutive OLT candidates underwent right heart catheterization with pressure measurements at baseline and after infusion of 1 L of crystalloid. MRI, chest roentgenography, electrocardiography, and echocardiography were also performed as routine screening techniques. Sixteen patients in intensive care unit with normal liver function served as controls. RESULTS: After volume infusion, pulmonary hypertension (mean pulmonary artery pressure greater than 25 mm Hg) developed in 9 of 25 OLT candidates with elevations in both pulmonary capillary wedge and mean pulmonary pressures. In contrast, 0 of 16 controls experienced pulmonary hypertension (p < 0.01). Although routine modalities did not predict this hemodynamic response, PFI had a 94% specificity and 78% sensitivity. CONCLUSIONS: OLT candidates exhibit volume-induced pulmonary hypertension with responses suggestive of left ventricular dysfunction. The significance of this observation is unknown, but the MRI-derived parameter, PFI, may serve as a screening technique to limit catheterization to a select group of OLT candidates.

Adult↗
PubMed1995

Magnetic resonance imaging and hepatic hemodynamics: correlation with metabolic function in liver transplantation candidates.

BACKGROUND: Preoperative assessment of orthotopic liver transplantation candidates requires definition of both the anatomy and metabolic function of the native liver. Current evaluation techniques combine computed tomographic scanning, duplex ultrasonography with blood chemistry analysis, and physical stigmata of end-stage liver disease. Recently, magnetic resonance imaging (MRI) has emerged as an alternative method for delineation of hepatic and portal venous anatomy. In addition, MRI accurately measures hepatic volume and portal venous blood flow. METHODS: To examine the role of MRI-derived indexes of hepatic hemodynamics in the preoperative assessment of liver function, 39 consecutive liver transplantation candidates were studied in a prospective manner. Liver function (aspartate aminotransferase), alanine aminotransferase, alkaline phosphatase, total bilirubin, and albumin levels), hematologic indexes (complete blood cell count, prothrombin time), and Child's classification were determined at the time of evaluation. Axial breath-held multiplanar spoiled-gradient echo MRI measured hepatic volume, whereas a cine phase-contrast sequence perpendicular to the portal vein measured flow. RESULTS: Hepatic index, defined as hepatic mass corrected for body surface area, was found to correlate with prothrombin time (p < 0.04) and platelet count (p < 0.03) by multivariate regression analysis. Portal flow index (PFI), defined as portal flow corrected for hepatic mass), was associated with aspartate aminotransferase (p < 0.02), alanine aminotransferase (p < 0.04), and albumin (p < 0.03) by multivariate regression analysis. In addition, PFI was closely correlated with the patients' functional status as determined by Child's classification system. Increasing values of PFI were associated with declining hepatic functional reserve. Child's class A patients had a mean PFI that was two times less than that of Child's class B patients (0.26 +/- 0.04 versus 0.04 +/- 0.06 ml/min/gm; p < 0.02) and five times less than that of Child's class C patients (0.26 +/- 0.04 versus 1.05 +/- 0.14 ml/min/gm; p < 0.001). Similarly, the mean PFI associated with Child's class B was two times less than that of Child's class C (0.46 +/- 0.06 versus 1.05 +/- 0.14 ml/min/gm; p < 0.01). These data show that MRI-derived indexes of portal hemodynamics and hepatic mass (1) correlate well with biochemical indexes of hepatic dysfunction and (2) serve as anatomic and hemodynamic correlates to Child's functional classification. CONCLUSIONS: We conclude that MRI may serve to noninvasively delineate preoperative hepatic vascular anatomy and metabolic dysfunction in candidates undergoing examination for liver transplantation.

Adult↗
PubMed1995

Hepatitis C virus infection in the immunocompromised patient.

With this review we have attempted to highlight key issues in the diagnosis and management of HCV infection in immunocompromised patients. Much of the information is preliminary and will require careful assessment with prospective collection of data in large numbers of patients. With the advent of new assays, our ability to diagnose infection is accurate. We are still lacking sufficient data regarding the natural history of infection to aid substantially in the management of these patients. Finally, we desparately need new therapeutic approaches to this disease. Hopefully, with greater understanding of the replication of this virus and the mechanism of liver pathogenicity, novel approaches to treatment will be developed.

HIV Infections↗
PubMed1995

Mitral annular calcification in CAPD patients with a low degree of hyperparathyroidism. An analysis of other possible risk factors.

Chronic renal failure has been suggested as a risk factor for mitral annular calcification (MAC), a degenerative process of the mitral annulus. The objective of the present study was to define MAC risk factors at the start of dialysis and 'de-novo' appearance after medium- or long-term CAPD, in a non-selected population (135 patients) with a low degree of secondary hyperparathyroidism. Echocardiographic studies were performed at the beginning of CAPD and every 1-1.5 years thereafter. Diagnosis of MAC was established by M mode and 2-D study. Seventeen of 135 patients studied at the start of dialysis showed MAC. Patients who showed MAC were older and presented a higher mean systolic blood pressure. The other anthropometric/demographic parameters did not show statistically significant differences. MAC thickness: mean 6.21 +/- 3.65 mm (range 3-17.2 mm). The posterior annulus was universally affected and in four patients the anterior annulus was involved. Seventeen of 76 patients included in the follow-up study developed MAC. No significant differences for demography, except age, with MAC patients being older, were found. Mean time on CAPD until de-novo MAC diagnosis was 49.7 +/- 26.9 months. MAC thickness: mean 4.97 +/- 1.6 mm (range 3-8.42 mm). The posterior annulus was affected in all patients except for one and in four patients the anterior annulus was involved. The most remarkable echocardiographic feature is the almost constant association of MAC with left atrial dilatation (LAD). The last one does not seem a consequence of mitral insufficiency, or systolic dysfunction. Left ventricular hypertrophy was universally found, with no different intensities for patients with or without MAC. In conclusion, a high incidence of mitral annular calcification has been found in CAPD patients. Our data do not confirm the role of classical invoked risk factors. Blood CaP product under 75, a moderate to mild degree of hyperparathyroidism and/or hypertension with left ventricular hypertrophy do not seem to be isolated risk factors during the CAPD period. Length of time on CAPD, for unknown reasons, seems to favour the appearance of MAC. At starting dialysis, high systolic blood pressure and left ventricular hypertrophy seem to be related to MAC. Diabetes appears to represent an additional risk factor. Further research on mitral annular calcification pathogenesis and its consequences is urgently required.

Calcinosis↗
PubMed1994

Modification of testicular cytochrome P-450 after fenitrothion administration.

1. The effect of fenitrothion on testicular microsomal system was analyzed and compared to the modifications induced by the drug at the hepatic level. 2. Acute (165 mg/kg, 1 day) and subacute (55 mg/kg, 3 days) administration of fenitrothion caused a significant decrease on testicular cytochrome P-450 content (51 and 50% respectively) but no modification on cytochrome b5 and NADPH cytochrome c reductase. No changes were induced by fenitrothion in testicular microsomal system after chronic treatment (5.5 mg/ml, 30 days). 3. Results obtained in the liver were very similar to those observed in testis even though the percentage of cytochrome P-450 inhibition obtained after acute and subacute drug administration (45 and 43%) was smaller. 4. In addition, changes in testosterone blood concentrations were also analyzed. A significant reduction of hormone plasma levels were detected at 165 and 55 mg/kg doses of fenitrothion (98% in both cases). Fenitrothion was not able to modify the levels of testosterone in the blood after chronic administration.

Androgens↗
PubMed1994

Casualties in Acapulco: results of a study on alcohol use and emergency room care.

This article reports the results of an emergency room study carried out in 1987 in three hospitals in Acapulco, Mexico. All patients were interviewed and breath tested for alcohol consumption. The data were analyzed using the case-control methodology. Cases were falls, motor vehicle accidents, fights and assaults, and home accidents. The control group included patients for whom accidents are less frequently reported as alcohol related, i.e., those reporting work place accidents, animal bites and recreational accidents. For positive breathalyzer readings (> or = 10 mg/100 ml of blood alcohol), the odds ration and 95% confidence intervals were statistically significant for falls, 3.45 (1.23-9.66); motor vehicle accidents, 3.85 (1.21-12.01); and fights and assaults, 5.23 (2.36-12.95). The association was non-significant for home accidents, 0.78 (0.20-2.98). Possible biases of this approach are discussed and recommendations are made for selecting better controls for future emergency room studies.

Accidental Falls↗
PubMed1994

Moncrief's technique for peritoneal catheter placement: experience of a CAPD unit.

A decrease in the peritonitis rate and the incidence of catheter exit-site/tunnel (E/T) infection are the most important factors affecting the permanent peritoneal catheter in continuous ambulatory peritoneal dialysis (CAPD) patients. Moncrief et al. have introduced a novel methodology (two phases) for peritoneal catheter placement (7.8). The most relevant characteristic is that the external portion remains buried on the subcutaneous tissue (sterile environment) during the healing process. After four to six weeks, the catheter is brought out through a small incision (0.5 cm) distal 2 cm from the subcutaneous cuff, and peritoneal dialysis may be initiated. The data available, presented by Moncrief et al., show a lower incidence of peritonitis rate and E/T infection with this implantation technique, when compared with a classic technique. The aim of this study is to learn if the placement of a peritoneal catheter with Moncrief's methodology decreases the incidence of complications related to peritoneal catheters. We treated 29 patients (group C) with the conventional procedure and 25 patients (group M) with the Moncrief technique. Follow-up was similar for both groups (C = 12.2 +/- 7.9 months vs M = 11.1 +/- 6.1 months, NS). The time buried was 3.23 +/- 0.9 weeks (2-5). Eleven patients completed four weeks with the catheter buried subcutaneously (group M-4). The incidence of E/T infection was similar for groups C and M, and lower in group M-4 (p < 0.05). The number of catheters free of infection was less in group C (31%) than in group M (46%) and M-4 (67%) (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Spontaneous nucleosomal DNA fragmentation in murine leukemic L1210 cells.

Spontaneous nucleosomal DNA fragmentation (SNDF), characteristic of apoptotic cell death was observed in a murine leukemic cell line grown to high density. This effect was eliminated by permitting free diffusional exchange with a large amount of complete medium. Cells seeded at low density did not show SNDF in a conditioned medium that had been used to culture cells with severe SNDF. Cells seeded at high density in the same conditioned medium showed pronounced SNDF, but addition of 10% fetal bovine serum to such a medium significantly reduced SNDF. These observations indicate that neither physical contact among cells in high density culture per se nor secretion of a death factor by the high density culture could account for the induction of SNDF. The results support a model in which the gradual depletion of a serum factor(s) leads to the activation of a cell death program that is manifested as SNDF.

Animals↗