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Biomedical subjects

D Parra

Publications and source records attributed to D Parra.

At least 19 recordsLinked to original sources
PubMed2005

The Bispectral Index Scale: its use in the detection of brain death.

OBJECTIVE: To evaluate the Bispectral Index Scale (BIS) monitor as a method of brain death (BD) detection. PATIENTS AND METHODS: We performed an observational prospective study in an intensive care unit (ICU) of a university hospital of 19 patients hospitalized nonconsecutively in the ICU with serious neurologic pathology and evolution toward BD. A BIS monitor, XP model, and the sensor "BIS Quatro" were used to continuously record values: suppression ratio (SR), quality of the signal index, and electromyographic (EMG) activity. RESULTS: The BD diagnosis was made through neurological clinical exploration and electroencephalogram (EEG) in all the cases. Additionally, transcranial Doppler was used in 13 patients. Coincident with clinical worsening, it was observed that there was a gradual decrease of the BIS value, together with a rise in the SR. In all the patients in which the BD diagnosis was confirmed, the BIS showed values of 0 and suppression rates of 100. Only one patient showed interferences, due to EMG activity, the same problem was detected when a conventional EEG was performing. After using a neuromuscular blocker, the values of BIS and SR were 0 and 100, respectively. CONCLUSIONS: The BIS is a noninvasive, simple, and easy to interpret method. All the patients with BD diagnosis except for one had a BIS value of 0 and TS of 100, showing a perfect correlation with the other diagnostic methods. The BIS cannot be used on its own for the confirmation of the BD, but it is a useful tool to detect the beginning of brain herniation.

Brain Death↗
PubMed2005

Non-heart-beating donors: an excellent choice to increase the donor pool.

A specific program was adopted to obtain organs, for transplant purposes from people who die at home or in the street from sudden or unexpected death (type I non-heart-beating donors [NHBD] according to the Maastricht classification). The objective of our program was to increase the donor pool by obtaining organs from well-selected potential donors who die at home, work, or in the street and are maintained on advanced life support (ALS) until hospital arrival. The great number of people who die in a previously healthy situation constitute an excellent source of organs for transplant purposes. Our program includes pre- and in-hospital attendance. Prehospital attendance is based on application of cardiopulmonary resuscitation in situ and ALS until arrival at hospital. In hospital, specific preservation maneuvers must be performed and family assessment and judge permission obtained. In the last 15 years, we developed a kidney transplant program with better results than transplants performed with organs obtained from encephalic death donors (EDD). A specific NHBD subprogram for lung transplant was developed with excellent results as well. We are now improving the liver transplant program. NHBD are an important source of human tissues, including pancreas islets. It is clear that NHBD are a great source of organs and tissues for transplant, and that this kind of program must be established in all countries in which legal regulations allow it.

Cadaver↗
PubMed2005

Pericardial effusion and cardiac tamponade in pediatric stem cell transplant recipients.

Pericardial effusion and cardiac tamponade is a rarely reported complication following stem cell transplant (SCT). The incidence among pediatric SCT recipients is not well defined. To assess the frequency of clinically significant pericardial effusions, we retrospectively examined clinically significant cardiac effusions at our center. Between January of 1993 and August 2004, clinically significant pericardial effusions were identified in nine of 205 patients (4.4%). The median age at the time of transplant was 9 years (range 0.6-18 years) and seven received an allogeneic transplant. All nine had normal cardiac function prior to transplant. The effusion developed at a median of 30 days (range 18-210 days). All allogeneic recipients had acute or clinically extensive graft-versus-host disease (GVHD) at the time the effusion was diagnosed. Seven patients (78%) required pericardiocentesis or surgical creation of a pericardial window. No patient died as a complication of the effusion or the therapeutic procedures. Clinically significant pericardial effusions are more common than previously reported in pediatric SCT recipients. Acute and chronic GVHD is an associated factor.

Adolescent↗
PubMed2004

Basal and postprandial substrate oxidation rates in obese women receiving two test meals with different protein content.

BACKGROUND & AIMS: Fuel utilisation and storage in lean and obese subjects seem to be differently affected by the macronutrient distribution intake. The aim of this intervention study was to explore the extent to which the fat mass status and the macronutrient composition of an acute dietary intake influence substrate oxidation rates. METHODS: Fuel utilisation in 26 women, 14 obese (BMI = 37.1 +/- 1.1 kg/m2) and 12 lean (BMI = 20.6 +/- 0.5 kg/m2) was measured over 6 h to compare the metabolic effect of a single balanced protein (HC) meal and a high protein (HP) single meal, which were designed to supply similar energy contents (1672 kJ). The macronutrient composition as a percentage of energy of the HC meal was 55% carbohydrate, 15% protein and 30% fat, while the HP meal contained 40% carbohydrate, 30% protein and 30% fat. Nutrient oxidation rates and energy expenditure were calculated by indirect calorimetry (hood system), whereas exogenous amino acid oxidation was estimated from the 13C isotopic enrichment of breath after oral administration of L[1-13C]leucine. RESULTS: Fasting lipid oxidation was higher in the obese than in the lean women (P < 0.05), and it was significantly correlated with body fatness (P < 0.01). A single HP meal consumption produced higher postprandial fat oxidation as compared with HC meal intake (P < 0.02), in both obese and lean subjects, with no apparent changes in glucose oxidation rates. Furthermore, postprandial fat utilisation after the test meal intake was higher in obese than in the lean women (P < 0.01). The time course of 13CO2 in breath followed a similar pattern in both dietary groups, although a non-statistically significant higher trend in protein and 13C-leucine oxidation was found in the HP group. CONCLUSIONS: Net lipid oxidation depends on both short-term dietary composition intake and fat body mass, being significantly higher after a relatively high protein meal as compared to a balanced diet intake and in obese women as compared to lean controls.

Adipose Tissue↗
PubMed2004

Generation, purification and functional characterization of three C3a anaphylatoxins in rainbow trout: role in leukocyte chemotaxis and respiratory burst.

Activation of the complement system leads to cleavage of the C3 molecule into C3b and C3a fragments. The C3a fragment plays a major role in immunity by inducing chemotaxis of eosinophils and mast cells and stimulating the respiratory burst in leukocytes. Although this anaphylotoxin has been well studied in mammals, there is currently a lack of information about the structure and function of C3a anaphylotoxins in non-mammalian vertebrate species. Therefore, in the present study, we have isolated and characterized three different C3a anaphylatoxin molecules from rainbow trout, a teleost fish. C3a was generated from the trout C3-1, C3-3, and C3-4 isoforms by incubating each individual C3 molecule with purified trout factor B/C2 and factor D in the presence of Mg2+, then purifying the resulting C3a molecules by gel filtration. SDS-PAGE, N-terminal sequence and mass spectrometric analysis demonstrated the high degree of purity and expected molecular masses of the three C3a molecules. We showed that although activated trout serum was able to induce complement-dependent chemotaxis in trout head kidney leukocytes, none of the three isolated C3a molecules induced chemotaxis in the same cells. In contrast, all three C3a molecules strongly stimulated the respiratory burst of head kidney leukocytes in a dose-dependent manner. When the carboxy-terminal Arg was removed from all three C3a molecules, their ability to induce the respiratory burst was lost. These studies, therefore, provide strong evidence for the existence of three functional C3a molecules in a non-mammalian vertebrate species and suggest that some of the basic mechanisms of action of the C3a molecule have been conserved for more than 300 million years.

Anaphylatoxins↗
PubMed2004

Monocyte function in healthy middle-aged people receiving fermented milk containing Lactobacillus casei.

BACKGROUND: Lactic acid bacteria have been suggested as a dietary strategy to enhance immune system activity. OBJECTIVE: The aim of the current work was to test the effects of a Lactobacillus casei fermented milk consumption on monocyte activity of middle-aged volunteers. DESIGN: Forty-five healthy volunteers, 24 women and 21 men (aged: 51 - 58 years), were randomized in two groups to receive three cups per day of a fermented milk containing L. casei DN114001 (108 - 1010/g) (n = 23), or placebo (n = 22), during 8 weeks. White blood cell count and the oxidative burst capacity of monocytes and granulocytes were examined with a FACScalibur. Measurements were performed at baseline and after the nutritional intervention, at day fifty-six. RESULTS: After the trial, no changes in immune cell proportions were detected in both groups, as well as in monocyte activity after the placebo consumption (p = 0.625). However, volunteers included in the probiotic-treated group increased (p = 0.029) their oxidative burst capacity of monocytes, and this increment inversely and significantly correlated with the intensity registered at baseline (r = -0.653, p = 0.004). CONCLUSIONS: Results showed that daily intake of fermented milk containing Lactobacillus casei was able to module the oxidative burst capacity of monocyte subset in healthy middle-aged people, particularly in subjects with lower initial levels. Thus, this nutritional strategy could be considered to maintain immune competence in ageing.

Aging↗
PubMed2002

Sib-parentage testing using molecular markers when parents are unknown.

The formulae for computing the so-called Sib Index using codominant alleles for (1) full-sib and (2) half-sib parentage are given. Hypothesis testing is based on the distribution of conditional likelihood ratio or Bayes' factor. Thresholds for rejecting the null hypothesis and P-values were obtained in function of the number of alleles and their frequency distributions. Simulations showed that a relatively low number of marker systems (e.g. 20) are enough to accept the hypothesis of sib parentage with a reasonable power for usual significance levels, but that a higher number would be necessary if full-sib against half-sib parentage is the contrast to be carried out. The effect of sampling variation on the allele frequencies on power calculations is also analysed.

Alleles↗
PubMed2001

Laboratory approach to mitochondrial diseases.

Dysfunction in mitochondrial processes has been related to several pathologies. In these disorders, the cell suffers oxidative imbalance that is mostly due to defects in pyruvate metabolism, mitochondrial fatty acids oxidation, the citric acid cycle or electron transport by the mitochondrial respiratory chain. These metabolic alterations produce mitochondrial diseases that have been related to inherited syndromes, such as MERRF or MELAS. The main affected organs are brain, skeletal muscle, kidney, heart and liver, because of the high energetic demand and the oxidative metabolism. Moreover, the relationship between mitochondrial dysfunction and neurodegenerative processes, such as Parkinson disease or Alzheimer disease, as well as ageing, has been shown. Because mitochondrias are the target of several xenobiotics, such as aspirin, AZT or alcohol consumption, mitochondrial impairment has also been proposed as a mechanism of toxicity. Most laboratory tests that are available in the diagnosis of mitochondrial illness are assayed in tissue biopsies and are usually difficult to interpret. Recently, it has been shown that non-invasive techniques, such as nuclear magnetic resonance or the 2-keto[1-(13)C]isocaproic acid breath test, may be useful to assess mitochondrial function. This article attempts to show the laboratory approach to mitochondrial diseases, reviewing new techniques that could be of great value in the research of mitochondrial function, such as the 2-keto[1-(13)C]isocaproic breath test.

Breath Tests↗
PubMed2000

Estrogen replacement therapy and the prevention of coronary heart disease in postmenopausal women.

The use of estrogen replacement therapy (ERT) for the prevention of coronary heart disease (CHD) is discussed. Cardiovascular disease is the number one cause of death in women. It is believed that the loss of estradiol production at menopause increases the risk of CHD. Theoretically, ERT should decrease CHD risk in postmenopausal women by maintaining at premenopausal levels the metabolic factors that affect CHD. Many mechanistic studies of the effects of estrogen on lipoproteins, hemostasis, carbohydrate metabolism, and vessel wall tone and reactivity support a cardioprotective role for estrogen. In addition, observational studies have found that ERT, with or without progesterone, significantly reduces the risk of CHD. However, mechanistic and observational studies can establish only an association, not a cause-and-effect relationship. Furthermore, bias may influence the risk estimates. The Heart and Estrogen/Progestin Replacement Study (HERS), published in 1998, was the first large, randomized, controlled trial to evaluate the efficacy of estrogen and progesterone replacement therapy in reducing CHD risk. Overall, the study found that continuous hormone replacement therapy (HRT) in women with CHD did not reduce cardiovascular risk at an average of 4.1 years of follow-up. In addition, there was an early increase in the risk of thromboembolic events. Although many mechanistic and observational studies suggest that ERT reduces the risk of morbidity and mortality from CHD in postmenopausal women, the only large, randomized, controlled study of this question to date failed to confirm this. Until data from ongoing studies are available, health care providers must reconsider prescribing ERT or HRT solely for the secondary prevention of CHD.

Coronary Disease↗
PubMed2000

Characterisation with stable isotopes of the presence of a lag phase in the gastric emptying of liquids.

BACKGROUND: Gastric emptying of non-nutrient liquids usually lacks the presence of an initial delay phase (lag phase), and so it has been considered to be monoexponential with an initial rapid phase followed by a slower emptying phase. However a lag phase in the gastric emptying of liquids can be found if there is a high caloric density in the liquid meal. AIM OF THE STUDY: To characterise with stable isotopes the presence of a lag phase in the gastric emptying of non-solid meals. METHODS: Healthy volunteers ingested a low caloric liquid meal (345 KJ/ 200 mL) (LCLM), a high caloric liquid meal (1135 KJ/180 mL) (HCLM) or a semisolid meal (1403 KJ/500 mL) (SSM). Test meals were labelled with 13C-acetate. Breath samples were collected for 13CO2 measurement and data were fitted to a power exponential function. RESULTS: Non-solid meals can have different behaviour related to the initial emptying. The presence of a lag phase in the gastric emptying of liquids was not masked by the processing of the tracer previous to its detection in breath. While the LCLM and SSM showed a rapid initial emptying phase (no lag phase), the HCLM has an initial slow emptying phase. The slower gastric emptying of the HCLM compared to the SSM was related to the presence of a lag phase in the gastric emptying of the HCLM. CONCLUSIONS: The 13C-acetate breath test is very accurate to identify and study the lag phase if present of liquid meals.

Acetates↗
PubMed2000

Retrospective evaluation of a potential interaction between azithromycine and warfarin in patients stabilized on warfarin.

STUDY OBJECTIVE: To investigate a potential interaction between azithromycin and warfarin. DESIGN: Retrospective case-control study. SETTING: Veterans Affairs medical center. PATIENTS: Fifty-two patients stable on anticoagulation therapy. INTERVENTION: Patients who received a prescription for azithromycin and warfarin at any time since the hospital was opened, June 1, 1995, to July 22, 1999, were identified through a computerized report generated from the pharmacy prescription package. MEASUREMENTS AND MAIN RESULTS: Patients having a stable international normalized ratio (INR; defined as a therapeutic INR +/- 0.2) for at least two consecutive visits before receiving an azithromycin prescription were reviewed. Changes in INR from before and after addition of azithromycin were compared with changes in a control group. Controls were identified from a computer-generated report of patients who received a prescription for terazosin and warfarin at any time since the hospital was opened to July 22, 1999 (terazosin was chosen as it has no known interaction with warfarin). These patients also had a stable INR for at least two consecutive visits before receiving the terazosin prescription. In patients with INRs on record within 14 days after starting azithromycin or terazosin (9 patients/group), the average change in INR was 0.18 +/- 0.48 in the azithromycin group and 0.07 +/- 0.49 in the terazosin group (p=0.60). For patients with an INR on record within 30 days after starting azithromycin or terazosin (26 patients/group), the average change in INR was 0.25 +/- 0.67 in the azithromycin group and 0.05 +/- 0.55 in the terazosin group (p=0.18). CONCLUSION: An interaction between azithromycin and warfarin was not observed in this retrospective review of patients with a stable INR receiving the combination.

Aged↗
PubMed2000

Retrospective evaluation of the conversion of amlodipine to alternative calcium channel blockers.

STUDY OBJECTIVE: To evaluate the effectiveness, safety, and costs associated with a formulary conversion from amlodipine to alternative calcium channel blockers. DESIGN: Retrospective study. SETTING: Veterans Affairs Medical Center. PATIENTS: One hundred patients with hypertension who were receiving amlodipine. INTERVENTION: Data from a random sample of 100 patients who were taking amlodipine and converted to a formulary calcium channel blocker from February 1, 1999-October 30, 1999, were entered into an Excel database for evaluation of the conversion. MEASUREMENTS AND MAIN RESULTS: Patients were required to have a diagnosis of hypertension and have had two consecutive clinic visits with blood pressure measurements (and no changes in antihypertensive therapy) before conversion. End points were changes in average systolic blood pressure, diastolic blood pressure, and mean arterial pressure (MAP) from the two clinic visits before and after conversion. In addition, data were collected and analyzed with regard to adverse drug reactions, average dosage of the alternative calcium channel blocker, number of additional antihypertensives begun or discontinued, and number of dosage changes in antihypertensives within the two visits after conversion, and the overall cost impact of conversion. Average systolic blood pressure was reduced from 141.6 +/- 15.1 to 139.2 +/- 15.3 mm Hg after the conversion (NS). Average diastolic blood pressure was significantly reduced from 74 +/- 9.5 to 72.6 +/- 10.1 mm Hg after conversion (p=0.032), as was MAP (97.0 +/-q 9.3 to 94.8 +/- 10.0 mm Hg, p=0.026). Five patients had other changes in therapy made concurrently at the time of conversion, and 19 had changes after conversion. When these patients were excluded from analysis, the reduction in systolic blood pressure after conversion was significant (141.4 +/- 14.5 to 137.7 +/- 14.3 mm Hg, p=0.022), as were reductions in diastolic blood pressure (74.4 +/- 9.4 to 71.7 +/- 9.8 mm Hg, p=0.014) and MAP (96.7 +/- 9.1 to 93.7 +/- 9.3 mm Hg, p=0.007). Of patients who had postconversion changes in therapy, 8 (42%) were converted to diltiazem ER, nifedipine CC, or doses of felodipine that were 50% of the original dose of amlodipine. The overall cost impact of the conversion was a net savings of $14,858/year for each 100 patients converted. CONCLUSION: Conversion from amlodipine to other calcium channel blockers resulted in statistically significant reductions in diastolic blood pressure and MAP, and was safe as well as cost-effective. Conversion to calcium channel antagonists other than felodipine or less than equal dosages of felodipine may require dosage titration. When converting patients from amlodipine, dosages usually should be equal to those of felodipine; if converting to other calcium channel antagonists, the need for adjustments should be anticipated.

Amlodipine↗
PubMed1999

Effect of the moderate consumption of olestra in patients receiving long-term warfarin therapy.

We conducted a prospective, randomized, double-blind, placebo-controlled, parallel-group trial to evaluate the effect of the moderate consumption of snacks containing olestra on the international normalized ratio (INR) in 40 patients receiving long-term warfarin therapy. Patients continued their warfarin regimen and were assigned to receive 1.5 servings/day (42 g) for 2 weeks of Pringles Original Flavor Fat Free Potato Crisps with Olean (12 g olestra/1.5 servings) or Pringles Original Flavor Potato Crisps (placebo group). Patients' INRs were measured weekly for 2 weeks. Thirty-six patients completed the first week of the trial. After 1 week, the mean change in the INR from baseline increased by 0.02 +/- 0.5 in the olestra group and by 0.17 +/-0.4 in the placebo group (p= 0.327). Ten patients in the olestra group and 12 in the placebo group completed the second week of the study. Mean change in the INR from baseline was similar at week 2, -0.18 +/- 0.38 and 0.09 +/- 0.53 (p=0.193), respectively. Gastrointestinal side effects (diarrhea, gas, bloating) occurred in three patients in the olestra group and five in the placebo group (p=0.3). Moderate consumption of snacks containing olestra did not significantly affect the INR (> 0.3 U) at 1 week in patients receiving long-term anticoagulation with warfarin. It does not appear that moderate consumption of these snacks would affect the INR after 2 weeks, but this must be confirmed in a larger sample with adequate power at 2 weeks.

Aged↗
PubMed1998

Calcium channel antagonists: morbidity and mortality--what's the evidence?

Recent studies have shown an association between the use of calcium channel antagonists for the treatment of hypertension and an increased risk of myocardial infarction, gastrointestinal hemorrhage and cancer. The interpretation of the results of these studies and their application to clinical practice requires an understanding of study design constraints, conflicting results and limitations in extrapolating study findings to other dosage strengths, formulations or agents within the calcium channel antagonist class. A review and critique of these studies provides background information on the controversial subject of using calcium channel antagonists for the treatment of hypertension. Despite the limitations of these studies, clinicians may want to select other classes of agents, including diuretics and beta blockers, as first-line therapy until the morbidity and mortality effects related to the use of calcium channel antagonists are clearly known.

Administration, Sublingual↗
PubMed1997

Prevalence of stroke in two samples (rural and urban) of old people in Spain. A pilot door-to-door study carried out by health professionals.

The aim of this study was to present the prevalence of stroke from a pilot study in old people. The urban site sample (Madrid) was made up of 397 subjects and the rural site sample (Arévalo, Avila) of 862 subjects. The study was performed with a door-to-door methodology. In the urban sample, the prevalence of stroke was 8.5% (CI 95% = 5.5-11.5%) and that of TIA was 2.1% (CI 95% = 0.6-3.6%). In the rural location the prevalence of stroke was 7.1% (CI 95% = 5.4-8.8%). This prevalence of stroke is higher than in other Spanish studies. These results need to be confirmed in a wider investigation.

Aged↗
PubMed1997

Density of intimal smooth muscle cells in the coronary arteries of Bolivians.

OBJECTIVE: To test an equation that uses measurements of fibroplastic intimal thickening and foam cell infiltrates, precursors for necrotic cores of atherosclerotic plaques in coronary arteries, to compute anticipated amounts of atheronecrosis. Data from New Orleans, La, and La Paz, Bolivia, afforded the opportunity to test the precision of the equation by comparing findings in separate populations. METHODS: Coronary arteries retrieved at autopsy in La Paz, Bolivia, were processed into hematoxylin-eosin-stained paraffin sections along with a parallel series in New Orleans. RESULTS: The Bolivian data fit the equation without modification. Findings showed the precursors of atheronecrosis to progress at the slowest rate in Bolivians, at the fastest rate in New Orleans men, and at an intermediate rate in New Orleans women. CONCLUSIONS: The population with the most extensive atheronecrosis in aging subjects also had the greatest degrees of precursor changes in young adults. An equation that describes these principles precisely applies equally well to all three of the populations examined here, which are the only ones studied to date.

Adult↗