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Biomedical subjects

A Linares

Publications and source records attributed to A Linares.

At least 19 recordsLinked to original sources
PubMed2006

Nutritional control, gene regulation, and transformation of vascular smooth muscle cells in atherosclerosis.

Contractile-state smooth muscle cells (SMC), the only cell type in the arterial media, undergoes migration to the intima, proliferation, and abundant extracellular matrix production during the early stages of atherosclerosis. This involves the ingestion of low-density lipoprotein (LDL) and modified or oxidised LDL by macrophages together with SMC by several pathways including a scavenger pathway leading to accumulation of cholesterol esters and formation of foam cells. High-plasma cholesterol levels constitute a major causative risk for atherosclerosis. The membrane-bound transcription factor called sterol regulatory element binding protein (SREBP) activates gene-encoding enzymes of cholesterol and fatty acid biosynthesis. The SREBP expression, in response to diet, shows that are involved in both lipogenesis and cholesterol homeostasis, moreover SREBPs are regulated directly by cholesterol. Animal models were used in trials of atherosclerosis, and cholesterol feeding has been described elsewhere as producing atherosclerotic lesions. We have examined the morphological, molecular and proliferative change in arterial SMC mimicking such a cholesterol diet, this transformed SMC is a good model to study the alterations of the differentiated state of SMC, and the transformation into foam cell, caused by cholesterol-rich diet. Despite the complexity of the interactions in atherosclerosis, there are many opportunities to affect the homeostatic balance of the artery wall at SMC levels. We have considered here some of the possible targets for intervention with promising strategies for the nutritional control of the genes, and, in a general way, the possibilities for modulating the expression of genes influencing atherosclerosis.

Animals↗
PubMed2005

Modifications of renal blood flow and serum interleukin levels induced by laparoscopic and open living donor nephrectomies for kidney transplant: an experimental study in pigs.

The increase of intraabdominal pressure (IAP) during laparoscopy modifies renal blood flow (RBF). However, laparoscopic techniques are less invasive than open procedures. The use of interleukins (IL) to evaluate operative trauma of different surgical techniques is controversial. The aim of the study was to analyze the, modifications induced by laparoscopic and open nephrectomies on RBF, renal function and IL levels. Thirty pigs underwent left nephrectomy, 15 by laparoscopy and 15 by an open approach in an experimental autotransplant model. A significant reduction in RBF was observed among the laparoscopic (80 +/- 27 mL/min) versus the open group (263 +/- 3 mL/min, P < .05). Laparoscopy reduced glomerular filtration (GF) (37.6 +/- 1.1%) to a greater extent than an open technique (80.5 +/- 0.4%; P < .05). Serum levels of IL-2, IL-6, IL-10, and tumor necrosis factor (TNF) were lower during laparoscopic than open nephrectomy: 6.8 +/- 0.6 versus 13 .9 +/- 1.1 pg/mL for IL-2, 46.2 +/- 2.3 versus 84.4 +/- 2.5 pg/mL for IL-6, 26.1 +/- 2.4 versus 92.8 +/- 12.6 pg/mL for IL-10, and 17.6 +/- 2.1 versus 38.5 +/- 4.8 pg/mL for TNF (P <.001). In conclusion, laparoscopic nephrectomy for living donor kidney transplant induced significant reductions in RBF and GF. However, there was less increase in IL levels during laparoscopic than the open approach. The influence of these circumstances on graft function after kidney transplantation is not clearly established.

Animals↗
PubMed2004

Children's meal patterns have changed over a 21-year period: the Bogalusa Heart Study.

OBJECTIVE: The objective of this study was to analyze children's meal patterns over 2 decades. DESIGN: One 24-hour dietary recall was collected on each child who participated in one of seven cross-sectional surveys. SUBJECTS/SETTING: Dietary intake data were collected on 1,584 10-year-old children (65% white, 35% African American), in Bogalusa, LA, from 1973 to 1994. STATISTICAL ANALYSES: Descriptive statistics and one-way analysis of variance adjusting for gender and ethnicity. RESULTS: From 1973 to 1978, there was a marked increase (P<.0001) in the percentage of children who skipped breakfast, from 8.2% to 29.6%. When school breakfast was introduced in 1981, the proportion of children skipping breakfast declined to 12.5% (P<.01). From 1973-1974 to 1993-1994, the percentage of children eating a school lunch declined from 89.7% (1973-1974) to 78.2% (1993-1994) (P<.001); eating lunch brought from home increased from 5.9% to 11.1% (P<.01); consuming a home dinner decreased from 89.2% to 75.9% (P<.01); eating a dinner prepared outside the home increased from 5.4% to 19.0% (P<.01); consuming a meal at a restaurant increased from 0.3% to 5.4% (P<.0001); consuming snacks decreased (P<.0001); total eating episodes decreased from 6.6 to 5.2 (P<.0001); and eating time span significantly decreased from 12.4 hours to 11.5 hours (P<.0001). Despite these changes in meal patterns, no associations were found between meal patterns and overweight status. CONCLUSIONS: Striking alterations in the meal patterns of children occurred over the 2-decade period. These changes may have implications for the changes in the dietary intakes of children during the same time. However, data from this study do not support an association between meal patterns and children's overweight status. Further research with multiple days of assessment is needed to better understand the complexity of diet as it relates to childhood obesity.

Analysis of Variance↗
PubMed2001

Antipyrine clearance and metabolite formation in primary biliary cirrhosis.

The disposition of antipyrine is altered and may be a prognostic factor in the presence of various types of hepatic dysfunction. The object of the present study was to investigate whether antipyrine clearance and metabolite formation are useful to detect altered metabolic function in primary biliary cirrhosis. Saliva clearance of antipyrine and the formation clearance of antipyrine metabolites (hydroxymethylantipyrine, HMA; norantipyrine, NORA; and 4-hydroxyantipyrine, OHA) were investigated in a group of 34 women with biopsy-proven PBC (mean age 60 years; range 39-87 years) and in 15 healthy control women (mean age 62 years; range 46-78 years). Parameters of antipyrine clearance of patients in stage I and II were similar to those observed in healthy subjects. When compared to patients in stage I, patients in advanced stages showed a reduction in antipyrine clearance (-29% and -44% in stages III and IV, respectively) and increases in antipyrine half-life (+24% and +75% in stages III and IV, respectively). The reduction in antipyrine clearance was due to a reduction in the formation of all three antipyrine metabolites, with the formation clearance of both HMA and NORA decreasing to a slightly greater extent than that of OHA. Antipyrine clearance correlated significantly with serum bilirubin (P < 0.017) and the Mayo risk score (P < 0.001). Logistic regression analysis indicated that antipyrine clearance was an independent predictor of the histological stage of the disease (P < 0.001). Antipyrine clearance and metabolite formation is a sensitive parameter for assessing hepatic metabolic function in primary biliary cirrhosis.

Adult↗
PubMed2001

The reversal of the inhibition on lipids synthesis by L-659,699 in arterial smooth muscle cells cultures.

The beta-lactone isolated from Fusarium sp. termed L-659,699 is a potent specific inhibitor of the enzyme 3-hydroxi-3-methylglutaril coenzyme A (HMG-CoA) synthase. In cultures of smooth muscle cells (SMC) isolated from aortic-arch of control (C-SMC) and 5% of cholesterol diet (Ch-SMC) treated chicks, the incorporation of (14C)-acetate to lipids (cholesterol, triacylglycerides and cholesterol ester) were greater in Ch-SMC cultures than in C-SMC and the presence of 0.05 microM L-659,699 for 2 h in the incubation medium decrease the synthesis of cholesterol however the triacylglycerides synthesis increase. The effect of inhibitor is stronger in young cultures (3-4 steps) than in the older ones (11-12 steps). In young C-SMC and Ch-SMC cultures the inhibition of cholesterol and triacylglycerides synthesis by L-659,699 was reversal.

Animals↗
PubMed2001

Presence of bacterial infection in bleeding cirrhotic patients is independently associated with early mortality and failure to control bleeding.

Bacterial infection is strongly associated with gastrointestinal bleeding in cirrhotic patients and seems to be related with the failure to control bleeding. The aims of this study were to assess the influence of infections on the failure to control bleeding and death in cirrhotic patients without antibiotic prophylaxis. Ninety-one consecutive bleeding cirrhotic patients were analyzed. Bleeding was managed using somatostatin with sclerotherapy for active bleeding. Screening for bacterial infection (analysis and culture of blood, urine, ascitic and other fluids, together with chest radiography) was made at time 0 and when clinical signs suggested infection. The cause of bleeding was variceal in 72 (79%) patients. Failure to control bleeding occurred in 24 (26%) patients, and 10 (11%) of the patients died. Compared with the group without infection, failure to control bleeding (65% vs 15%; P < 0.001) and mortality (40% vs 3%; P < 0.001), were observed more frequently in patients with infection. Multivariate analysis showed that bacterial infection (OR = 9.7; P < 0.001) and the presence of shock (OR = 3.5; P < 0.05) were independently associated with failure to control bleeding. Bacterial infection (OR = 12.6; P < 0.01), encephalopathy (OR = 6.9; P < 0.05), and shock (OR = 5.8; P < 0.05) were identified as predictive of death. In conclusion, in bleeding cirrhotic patients bacterial infection is associated with failure to control bleeding as well as mortality.

Female↗
PubMed2000

Alterations in 3-hydroxy-3-methylglutaryl-CoA reductase mRNA concentration in cultured chick aortic smooth muscle cells.

We observed and compared alterations in 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase at the transcriptional level in unsynchronized, three-passage cultures of smooth-muscle cells from the aorta of chicks fed on a control diet (C-SMC) and those of chicks fed on a similar diet plus cholesterol (Ch-SMC). Alterations in reductase mRNA concentrations in senescent cultures were much lower. We used a modification of the competitive (c) reverse transcription polymerase chain reaction method, using a Thermus thermophilus DNA polymerase (Tth pol) to quantify the very scarce species of HMG-CoA reductase mRNA in samples of cytoplasmic SMC mRNA. We cloned and sequenced a 199 bp cDNA fragment of chicken HMG-CoA reductase, which encoded a region of 66 amino acids belonging to the catalytic domain of the enzyme. HMG-CoA reductase mRNA concentrations from young C-SMC cultures rose 3.89-fold 4 h after the change of medium and returned to base levels between 8 to 12 h afterward. Concentrations in Ch-SMC cultures increased less (2.36-fold) 8 h after the change to fresh medium. Increases in reductase mRNA in senescent cultures of Ch-SMC and C-SMC measured under similar conditions were only 1.28- and 1.39-fold, respectively.

Amino Acid Sequence↗
PubMed2000

Fish oil reduces cholesterol and arachidonic acid levels in plasma and lipoproteins from hypercholesterolemic chicks.

The value of fish oil for prevention and/or treatment of human atherosclerosis has not been fully established. This study shows that replacement of saturated fat in young chick diet with menhaden oil produced a significant reversion of the hypercholesterolemia previously induced by coconut oil feeding. Fish oil also produced a clear decrease of plasma triacylglycerol levels. Coconut oil increased the percentages of 12:0 and 14:0 fatty acids, while menhaden oil increased those of 20:5 n-3 and 22:6 n-3. Percentages of 20:4 n-6, 18:2 n-6 and 18:1 n-9 significantly decreased by fish oil addition to the diet. Total cholesterol, phospholipid and protein contents of high and low density lipoproteins increased by coconut oil feeding. When coconut oil was replaced by menhaden oil, total cholesterol was significantly reduced in high, low and very low density lipoproteins. All chemical components of VLDL were decreased by menhaden oil feeding. Our results show a strong hypocholesterolemic effect of menhaden oil when this fat was supplemented to hypercholesterolemic chicks. The clear decrease found in arachidonic acid content of chick plasma and lipoproteins may contribute to the beneficial effects of fish oil consumption by lowering the production of its derived eicosanoids.

Animals↗
PubMed2000

Metabolism of palmitic and docosahexaenoic acids in Reuber H35 hepatoma cells.

In this work, we have modified the fatty acid composition of Reuber H35 hepatoma cells by supplementation of the culture medium with a saturated (palmitic) or a polyunsaturated (docosahexaenoic) acid. These fatty acids were incorporated into total lipids and phospholipids of hepatoma cells. Palmitic acid readily increased the percentage of its monounsaturated derivative (16:1 n-7). When both fatty acids were supplemented at the same concentration, the percentage of docosahexaenoic acid in the total lipids and phospholipids of Reuber H35 cells increased more than that of palmitic acid. Although the levels of 16:0 increased, the addition of docosahexaenoic acid to the culture medium decreased the percentages of monoenoic acids. From our results, it can be concluded that palmitic and docosahexaenoic acids modify the fatty acid composition of Reuber H35 hepatoma cells. The profound changes induced by docosahexaenoic acid, especially those in the phospholipid fraction, may be of great interest given the main role of these components in the regulation of chemical and physical properties of biological membranes and/or membrane systems.

Carcinoma, Hepatocellular↗
PubMed2000

Impact of community intervention to reduce patient delay time on use of reperfusion therapy for acute myocardial infarction: rapid early action for coronary treatment (REACT) trial. REACT Study Group.

BACKGROUND: Reperfusion therapy for acute myocardial infarction (AMI) is a time-dependent intervention that can reduce infarct-related morbidity and mortality. Out-of-hospital patient delay from symptom onset until emergency department (ED) presentation may reduce the expected benefit of reperfusion therapy. OBJECTIVE: To determine the impact of a community educational intervention to reduce patient delay time on the use of reperfusion therapy for AMI. METHODS: This was a randomized, controlled community-based trial to enhance patient recognition of AMI symptoms and encourage early ED presentation with resultant increased reperfusion therapy rates for AMI. The study took place in 44 hospitals in 20 pair-matched communities in five U.S. geographic regions. Eligible study subjects were non-institutionalized patients without chest injury (aged > or =30 years) who were admitted to participating hospitals and who received a hospital discharge diagnosis of AMI (ICD 410); n = 4,885. For outcome assessment, patients were excluded if they were without survival data (n = 402), enrolled in thrombolytic trials (n = 61), receiving reperfusion therapy >12 hours after ED arrival (n = 628), or missing symptom onset or reperfusion times (n = 781). The applied intervention was an educational program targeting community organizations and the general public, high-risk patients, and health professionals in target communities. The primary outcome was a change in the proportion of AMI patients receiving early reperfusion therapy (i.e., within one hour of ED arrival or within six hours of symptom onset). Trends in reperfusion therapy rates were determined after adjustment for patient demographics, presenting blood pressure, cardiac history, and insurance status. Four-month baseline was compared with the 18-month intervention period. RESULTS: Of 3,013 selected AMI patients, 40% received reperfusion therapy. Eighteen percent received therapy within one hour of ED arrival (46% of treated patients), and 32% within six hours of symptom onset (80% of treated patients). No significant difference in the trends in reperfusion therapy rates was attributable to the intervention, although increases in early reperfusion therapy rates were noted during the first six months of the intervention. A significant association of early reperfusion therapy use with ambulance use was identified. CONCLUSIONS: Community-wide educational efforts to enhance patient response to AMI symptoms may not translate into sustained changes in reperfusion practices. However, an increased odds for early reperfusion therapy use during the initiation of the intervention and the association of early therapy with ambulance use suggest that reperfusion therapy rates can be enhanced.

Adult↗
PubMed1999

Dietary fish oil reduces cholesterol and arachidonic acid levels in chick plasma and very low density lipoprotein.

The mechanisms involved in the hypolipidemic effects of fish oil have not been clearly established. This study shows that supplementation of 10% menhaden oil to the chick diet for 7 days produced a significant hypocholesterolemia and hypotriglyceridemia. Fatty acid composition of chick plasma drastically changed by the same dietary manipulation. Percentages of 20:5 and 22:6 n-3 fatty acids strongly increased, while percentages of 20:4 n-6, 18:2 n-6, and 18:1 n-9 significantly decreased. Changes observed in the relative percentages were parallel to those obtained in the amount of each fatty acid. Ratio of n-3/n-6 clearly decreased in plasma by fish oil feeding. Total cholesterol and triacylglycerol contents decreased in high density lipoprotein (HDL) but did not change in low density lipoprotein (LDL). All chemical constituents of very low density lipoprotein (VLDL) significantly decreased after the first week of menhaden oil supplementation to the diet. Similar modifications in fatty acid composition of the three lipoprotein fractions were also found. Our results suggest that the hypocholesterolemic effects of fish oil may be mediated by the depletion in VLDL synthesis and secretion into the chick plasma. On the other hand, the strong decrease found in the arachidonic acid (AA) content of chick plasma and lipoproteins may contribute to the beneficial effects of fish oil consumption by lowering the production of its derived eicosanoids.

Animals↗
PubMed1998

Comparison of reported symptoms of acute myocardial infarction in Mexican Americans versus non-Hispanic whites (the Corpus Christi Heart Project).

This study examines whether there are differences between Mexican Americans and non-Hispanic whites in reported symptoms of acute myocardial infarction (AMI). The symptoms experienced by patients identified in a community-based surveillance program were examined to determine whether between-group differences existed by ethnicity, gender, and diabetic status. Data were available regarding the symptoms of 589 patients, between the ages of 25 and 74 years, who were hospitalized and diagnosed as either having definite or possible AMI in special care units at 1 of 7 hospitals in Corpus Christi, Texas. The most frequently reported symptoms were chest pain (83.2%), chest pressure or discomfort (67.6%), sweating (64.2%), fatigue (62.6%), dyspnea (60.3%), and arm or jaw pain (58.2%). After adjusting for age, diabetes mellitus, and gender, and relative to non-Hispanic whites, Mexican Americans were more likely to report chest pain, upper back pain, and palpitations, and less likely to report arm or jaw pain. Likewise, relative to men, women were more likely to report fatigue, dyspnea, dizziness, upper back pain, palpitations, and cough, and were less likely to report chest pain. Significant differences were also observed when older patients' symptoms were compared with younger patients' symptoms.

Adult↗
PubMed1998

Changes in cultured arterial smooth muscle cells isolated from chicks upon cholesterol feeding.

We have developed cultures of smooth muscle cells (SMC) isolated from arterial hypercholesterolemic chicks (cholesterol-SMC). These cultures are suitable for the study at the molecular level of the changes in arterial SMC induced by a cholesterol diet. By using a strong dose of cholesterol (5%) for 10 d, we obtained very proliferative SMC which became foam cells after 30 d in culture. On the other hand, SMC cultures isolated from control-fed chicks had a lower growth rate than the SMC ones under the same culture conditions. DNA synthesis was fourfold greater in cholesterol-SMC than in control-SMC cultures. Intracellular cholesterol concentrations were the same in both cholesterol and control SMC during the first 14 d of culture but afterward increased in differing ways: after 20 d of culture the cholesterol-SMC increased their cholesterol content to double the control. We give here the results obtained from transmission electron microscopy, lipid analysis, proliferation studies, DNA, RNA and protein synthesis, and then discuss their implications.

Animals↗
PubMed1998

Synergism between the effects of dietary cholesterol and coconut oil on plasma, liver and lipoprotein composition of neonatal chick.

The nature of the synergism between dietary factors and the development of atherosclerosis has not been fully defined. Our studies showed that simultaneous supplementation of 10% saturated fat rich in 12:0 and 14:0 fatty acids (coconut oil) plus 1% cholesterol to the diet produced a sharp increase of plasma cholesterol, indicating a synergic influence of both dietary constituents. This increase was especially patent in the VLDL fraction, modifying the distribution of other lipid components between the core and the surface of these particles. These changes are consistent with the atherogenic function of VLDL and its responsiveness to dietary manipulation.

Animals↗
PubMed1998

[Arterioportal fistula and hemobilia in a patient with hepatic transplant].

The case of a 36-year old male liver transplant recipient hospitalized for upper digestive hemorrhage, jaundice and pain in the right hypochondrium is herein reported. Two hepatic biopsies had been performed 60 and 7 days prior to admission. Bleeding was observed to be from the biliary tract by endoscopy and an arterioportal fistula in the right hepatic lobe by echo-doppler and arteriography was seen. Treatment with selective embolization by arteriography was satisfactory with biliary tract drainage not being required. Doppler echography was used to control the evolution of the patient.

Adult↗
PubMed1997

Dietary fiber, Hispanics, and breast cancer risk?

The cancer rates of immigrant populations in the United States must be taken into account when looking at the importance of diet and culture as it relates to cancer prevention. Unfortunately, some nutrition studies targeted toward nontraditional white populations have not adequately confronted the issue of cultural meaning in efforts to gather dietary data accurate enough to support nutritional analyses, identify marginal diets, or relate risk to dietary patterns. The study presented here resolves many of the culturally specific issues utilizing awareness, attention, and judicious combination of culturally sensitive qualitative and quantitative research techniques. The importance of such a study in an Hispanic population is based on the fact that the age-adjusted rate of breast cancer in countries such as Mexico is among the lowest in the world. In addition, although one of the fastest-growing minority groups in the United States, Hispanic women living in this country have been shown to have the lowest incidence of the mortality rates from this disease across most geographic regions of the United States. Therefore, one might speculate that dietary factors, which have been shown to play a role in breast cancer prevention, may account for this difference. It is well recognized that the traditional Hispanic diet is rich in protective nutrients such as dietary fiber. It is known that through complex mechanisms, dietary fiber works to reduce the amount of estrogens in the body. Research also indicates that it is the level of endogenous estrogen in the body that may influence the onset of breast cancer. In order to better understand how dietary factors may be associated with breast cancer in Hispanic women, it is important that one develop the proper tools to discern any potential differences. Therefore, we developed an approach to obtaining dietary fiber information from a small cohort of 22 Houston-area Hispanic women as a vanguard study for a larger breast cancer prevention trial. Two separate dietary assessment instruments were utilized, a three-day food record and the Southwest Food Frequency Questionnaire. The mean intake of dietary fiber was 16 g/day according to the food record and 21 g/day according to the SWFFQ. Fruits, vegetables, breads, cereals, and beans provided for most of the participants' dietary fiber intake. These results support evidence that the Hispanic population's dietary fiber intake is higher than that for other groups, and this may help explain the lower incidence of breast cancer among some Hispanic populations.

Aged↗
PubMed1997

Newborn genetic identification: a protocol using microsatellite DNA as an alternative to footprinting.

Newborn identification by foot- or finger-printing presents serious drawbacks. This study proposes an alternative method based on DNA analysis of blood-spots taken from the newborn child. CSF1PO, TPOX and TH01 microsatellite loci were chosen to develop a fast and reliable protocol to be applied in cases where it is suspected that newborn children have been exchanged. The advantage of these loci is that one can simultaneously amplify them by PCR multiplex reaction and determine their alleles, thereby reducing the time needed for identification tests. Moreover, the amplification products of these loci are very small (< 350 bp) and so can be analyzed in samples with degraded DNA. We have been able to prove that it is possible to obtain results in blood-spots taken from newborns up to 13 years before and kept at room temperature. Thus the protocol proposed here can be applied in long-term post-natal identification cases.

Base Sequence↗