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Biomedical subjects

M Fernandez

Publications and source records attributed to M Fernandez.

At least 91 records · Page 5Linked to original sources
PubMed1998

Trends in Asian American racial/ethnic intermarriage: a comparison of 1980 and 1990 census data.

"In this paper, we use data from the 1990 [U.S.] census to compare patterns of Asian American intermarriage with those reported by Lee and Yamanaka (1990).... Our main findings show that: (i) the overall outmarriage rate has declined; (ii) Asian American inter-ethnic marriages (that is, marriages between two Asian Americans of different Asian ethnicities) have increased; and (iii) social distance, measured by an Index of Intermarriage Distance, between Asian Americans and other racial and ethnic groups has widened. We conclude by discussing some implications of the findings for the role of racial and ethnic intermarriage as an indicator of intergroup relations."

Americas↗
PubMed1998

[Still birth].

Explore the source record for details and available documents.

Family↗
PubMed1997

Outcome of cord-blood transplantation from related and unrelated donors. Eurocord Transplant Group and the European Blood and Marrow Transplantation Group.

BACKGROUND: Cord-blood banks have increased the use of cord-blood transplantation in patients with hematologic disorders. We have established a registry containing information on the outcome of cord-blood transplantation. METHODS: We sent questionnaires to 45 transplantation centers for information on patients receiving cord-blood transplants from 1988 to 1996. Reports on 143 transplantations, performed at 45 centers, were studied, and the responses were analyzed separately according to whether the donor was related or unrelated to the recipient. RESULTS: Among 78 recipients of cord blood from related donors, the Kaplan-Meier estimate of survival at one year was 63 percent. Younger age, lower weight, transplants from HLA-identical donors, and cytomegalovirus-negative serologic results in the recipient were favorable prognostic factors. Graft-versus-host-disease of at least grade II occurred at estimated rates of 9 percent in 60 recipients of HLA-matched cord blood and 50 percent in 18 recipients of HLA-mismatched cord blood. Neutrophil engraftment was associated with an age of less than six years (P = 0.02) and a weight of less than 20 kg (P = 0.02), and it occurred in 85 percent of patients receiving 37 million or more nucleated cells per kilogram of body weight. Among 65 patients who received cord blood from unrelated donors, the Kaplan-Meier estimate of survival at one year was 29 percent. Cytomegalovirus-negative serologic status in these recipients was associated with improved survival (P = 0.03) and was the most important predictor of graft-versus-host disease (P = 0.04). Neutrophil recovery occurred in 94 percent of the patients who received 37 million or more nucleated cells per kilogram from unrelated donors. CONCLUSIONS: Cord blood is a feasible alternative source of hematopoietic stem cells for pediatric and some adult patients with major hematologic disorders, particularly if the donor and the recipient are related.

Acute Disease↗
PubMed1997

The effect of oxygen delivery-directed resuscitation on splanchnic and hepatic oxygen transport after hemorrhagic shock.

BACKGROUND: Gut and hepatic dysfunction, during and after hypovolemic shock, have been implicated as causative mechanisms in the development of multiple system organ failure in the trauma patient. Current techniques of assessment of perfusion only detect changes in systemic oxygen transport. We designed an animal model that can measure changes in oxygen transport in the liver and gut during hypovolemic shock and resuscitation. MATERIALS AND METHODS: Animals were hemorrhaged to a mean arterial pressure (MAP) of 60 mm Hg and maintained at 60 mm Hg for 60 min. Animals were then assigned to one of three groups. Group I served as nontreatment controls. Group II received shed blood and saline in sufficient volumes to restore MAP to baseline. Group III animals were resuscitated with shed blood, saline, and donor blood to restore systemic oxygen delivery to the preshock value. RESULTS: The animals resuscitated to their baseline systemic oxygen delivery, Group III, had significantly higher systemic, hepatic, and splanchnic oxygen delivery than the remaining groups. In addition, Group III had higher oxygen consumption, portal flow, and hepatic artery flow than the blood pressure-directed group, Group II. The decrease in oxygen extraction ratio in the gut and liver was significantly greater in Group III than in Group II. CONCLUSIONS: These data show that hepatic and gut vascular beds are better perfused when resuscitation from hemorrhage is guided by systemic oxygen transport measurements compared to resuscitation guided by blood pressure.

Animals↗
PubMed1997

A noninvasive method for monitoring renal status at bedside.

RATIONALE AND OBJECTIVES: The authors demonstrate the feasibility of monitoring renal status continuously and noninvasively at a patient's bedside, avoiding both radioactivity and blood and urine samples. METHODS: Gadolinium-153-labeled ProHance and a glomerular filtration rate (GFR) standard technetium-99m-DTPA were coadministered to anesthetized normal and nephrectomized rats with their tails hanging in a PC 20 spin analyzer. Blood samples and T1 measurements were collected and analyzed. RESULTS: Log time plots of 153Gd, 99mTc (from blood samples) and T1 of the rat tails were all linear and parallel. Halftimes were 32 +/- 2, 32 +/- 6, and 32 +/- 6 minutes for the decay of the T1, 153Gd and 99mTc, respectively. The halftime of the nephrectomized animal was 2000 +/- 4000 minutes. CONCLUSIONS: T1 of an appendage remote from the kidneys reflects the concentration of gadolinium in the blood, which is in rapid equilibrium with tissue interstitial space gadolinium. The decay in T1 of the appendage reflects glomerular filtration. Thus, it is feasible to detect changes in renal status at a patient's bedside by monitoring T1 of a finger or wrist using a small, inexpensive magnet.

Animals↗
PubMed1997

Constitutive NOS isoforms account for gastric mucosal NO overproduction in uremic rats.

To study whether renal failure enhances gastric mucosal nitric oxide (NO) formation in the rat, we measured 1) in vivo NO concentration and 2) NO synthase (NOS) activity, content, and mRNA expression in gastric mucosal homogenates of uremic and sham-operated anesthetized rats. Gastric mucosal NO release was measured by an electrochemical technique. NOS content was analyzed by Western immunoblots, using specific monoclonal antibodies. Constitutive (Ca2+ dependent; cNOS) and inducible (Ca2+ independent; iNOS) NOS activities were assayed by following the conversion of L-[U-14C]arginine to [U-14C]citrulline. mRNA expression for the constitutive neuronal (ncNOS), endothelial (ecNOS), and iNOS isoforms was determined by reverse transcription-polymerase chain reaction. Under basal conditions, gastric mucosal NO concentration was significantly greater in uremic compared with control rats. This was accompanied by significantly greater gastric mucosal cNOS activity in uremic rats than in control rats, whereas no differences were observed in iNOS activity between both groups of animals. Moreover, total enzyme content and the levels of gastric mucosal mRNA expression for ncNOS, ecNOS, and iNOS showed no significant differences between uremic and sham-operated rats. These data confirm that, in uremic rats, enhanced Ca2+-dependent NOS activity is responsible for gastric mucosal NO overproduction and suggest that the main regulatory mechanism is not transcriptional but translational and/or posttranslational in nature.

Animals↗
PubMed1996

Coronary stenting in patients undergoing percutaneous transluminal coronary angioplasty during acute myocardial infarction.

Although coronary stenting has been useful in the treatment of patients with suboptimal results, abrupt closure, and threatening occlusion after percutaneous transluminal coronary angioplasty (PTCA), its use in patients with acute myocardial infarction (AMI) is controversial because of the presence of intracoronary thrombus. In this study intracoronary stenting was used to treat suboptimal results and complications in 30 patients (35 lesions) undergoing PTCA during AMI. There were 28 men and 2 women, mean age 58 +/- 12 years. Thirteen patients (43%) had undergone rescue PTCA because of unsuccessful thrombolysis. Four patients had Killip's grade IV, 5 Killip's grade III, and 21 Killip's grade < or = 2 heart failure. Stents were placed in the 35 lesions because of suboptimal result (n = 19), early loss (n = 9), abrupt closure (n = 2), and coronary dissection with threatening occlusion (n = 5). All stents were deployed successfully. In-hospital complications included 1 in-hospital death (3.0%); no patient required emergency coronary artery bypass graft surgery. One patient (3.0%) developed abrupt closure and was successfully treated with PTCA and intracoronary thrombolysis. Vascular complications requiring blood transfusion developed in 3 of 30 patients (10%). At 11.8 months (range 4 to 24) follow-up, there were no deaths or myocardial infarction. One patient underwent coronary artery bypass grafting. The remaining patients were free of angina at follow-up. Thus, intracoronary stents can be used successfully to treat both suboptimal results and complications occurring in patients undergoing PTCA during AMI.

Adult↗
PubMed1996

Seventeen copies of the human 37 kDa laminin receptor precursor/p40 ribosome-associated protein gene are processed pseudogenes arisen from retropositional events.

A cDNA coding for a 37 kDa polypeptide has been identified in several species as both the potential precursor of the 67 kDa laminin receptor (37LRP) and a putative ribosome-associated protein (p40). Interestingly, increased expression of this polypeptide (37LRP/p40) is consistently observed in invasive and metastatic cancer cells and is associated with poor prognosis. Southern-blot analysis of human genomic DNA predicted multiple copies of the 37LRP/p40 gene. In this study, we report that the number of copies of this sequence in the human genome is 26 +/- 2. We have sequenced and analyzed 19 genomic clones corresponding to the 37LRP/p40 gene and found that they were all processed pseudogenes. They all lack intronic sequences and show multiple genetic alterations leading in some cases to the appearance of stop codons. Moreover, they all bear characteristic features of retroposons as the presence of a poly(A)-tail at their 3' end and short direct repeated flanking DNA sequences. None of the pseudogenes analyzed present cis-elements in their 5' flanking region such as TATA or GC boxes. Our date reveal that over 50% of the 37LRP/p40 gene copies are pseudogenes most probably generated by retropositional events. The finding of multiple pseudogenes for the 37LRP/p40 suggests that the accumulation of several copies of this gene might have given a survival advantage to the cell in the course of evolution.

Base Sequence↗
PubMed1996

Design of conformationally rigid dimeric MRI agents.

The conformational flexibility of the linkage mechanism or tether between paramagnetic metal centers is explored to assess optimal structural characteristics of multimeric MRI contrast agents. Two dimeric paramagnetic chelates differing in linkage flexibility but similar in symmetry are compared Relaxivity, water hydration number, and reorientational times of the chelate groups are obtained, and the results demonstrate that greater linkage flexibility reduces overall relaxivity.

Chelating Agents↗
PubMed1996

Lipoprotein(a) is not elevated in non-diabetic microalbuminuric subjects. A longitudinal study of lipoprotein(a) concentrations and apolipoprotein(a) size isoforms.

Microalbuminuric non-diabetic subjects have an increased risk of cardiovascular disease which is not explained by standard risk factors. In diabetic patients, microalbuminuria is associated with increased lipoprotein(a) concentrations. We have determined lipoprotein(a) concentrations and duplicate measures of albumin excretion rate, on two occasions separated by around 3 years, in 125 Europid subjects aged 40-75 years without hypertension or glucose intolerance and in 49 offspring aged 15-40 years. The apolipoprotein(a) isoform size, the major genetic determinant of lipoprotein(a) concentration, was also determined. There were no differences in lipoprotein(a) concentration between the 42 subjects who were microalbuminuric on either or both samples at screening (median 9.4 mg/dl, 20th and 80th percentiles 2.6 and 46.3 mg/dl) and the 79 who had been normoalbuminuric at both collections (median 10.9 mg/dl, 20th and 80th percentiles 2.9 and 53.0 mg/dl; P = 0.58). Lipoprotein(a) concentrations were not significantly different between subjects with or without microalbuminuria at recell (P = 0.55) or between those with or without microalbuminuria classified by mean albumin excretion rate in either collection (P = 0.24 and P = 0.73, respectively). There were no significant relationships between albumin excretion rate as a continuous variable and lipoprotein(a) concentration, or between changes in the two variables over 3 years. The microalbuminuric and normoalbuminuric subjects had similar distributions of size isoforms. There were also no differences in lipoprotein(a) concentration or isoform distribution between offspring of microalbuminuric and of normoalbuminuric subjects. In conclusion, we found no evidence that microalbuminuric subjects with normal blood pressure and normal glucose tolerance have elevated concentrations of lipoprotein(a) to explain their increased cardiovascular risk.

Adolescent↗
PubMed1996

Evidence that two genomic species of Rhizobium are associated with Medicago truncatula.

Seventy-three isolates of rhizobia sampled from root nodules of Medicago truncatula were analyzed by restriction fragment length polymorphism (RFLP) of DNA regions amplified by the polymerase chain reaction (PCR) targeting the symbiotic plasmid (nifD-K, nodD1, and nodD2 genes) and the chromosome (16S rDNA plus intergenic spacer). Two genotypic groups were found, regardless of the DNA region targeted. These two groups were given the status of genomic species based on results of DNA/DNA hybridization.

Base Sequence↗
PubMed1996

Adaptive changes in adenosine receptors following long-term treatment with the adenosine receptor agonist R-phenylisopropyl adenosine.

Changes in brain A1 and A2A receptors and in the corresponding mRNA were studied using quantitative receptor autoradiography and in situ hybridisation. [3H]-DPCPX was used as an antagonist ligand at A1 receptors and [3H]-CGS 21680 as an agonist ligand at A2A receptors. Treatment of rats with the relatively A1 receptor selective adenosine analogue R-PIA (0.3 mg/kg) for 7 days in the presence of the peripherally acting antagonist 8-p-sulfophenyltheophylline (8-PST; 10 mg/kg) caused a decrease in the binding of the A1 receptor ligand, but not in that of the A2A receptor ligand. The effect on A1 receptors was also seen in the presence of 100 microM GTP that decreases agonist binding to insignificant levels. There was no change in either A1 or A2A receptor mRNA. No significant changes were detected following administration of either R-PIA or 8-PST alone. These results thus demonstrate an effect on brain A1 receptors after systemic administration of R-PIA in the presence of a peripherally acting adenosine antagonist, demonstrating that, under these conditions, the agonist reaches receptors in significant amounts.

Analysis of Variance↗
PubMed1996

Cellular sodium membrane transport and cardiovascular risk factors in non-insulin-dependent diabetes mellitus.

Association have been described between cardiovascular risk factors and abnormalities of both sodium-lithium countertransport (SLC) and sodium-hydrogen ion exchange in subjects with insulin-dependent diabetes mellitus. The data in subjects with non-insulin-dependent diabetes mellitus (NIDDM) are few and more conflicting. This investigation examines erythrocyte SLC rates and platelet sodium-hydrogen ion-exchange kinetics and their relationship to cardiovascular risk factors in 45 nondiabetic and 35 NIDDM white men. The two groups did not differ significantly in erythrocyte SLC or platelet buffering capacity, sodium-hydrogen ion-exchange maximal rate (Vmax), or Km for extracellular sodium. Within the whole group, controlling for the presence of diabetes, SLC correlated weakly with triglyceride concentration (r = .23, P = .05), but not with urinary albumin excretion rate (AER), systolic or diastolic blood pressure, body mass index (BMI), or concentrations of glucose, insulin, or total or high-density lipoprotein (HDL) cholesterol. Platelet sodium-hydrogen exchange was not significantly related to any cardiovascular risk factor studied. In conclusion, (1)SLC activity was not increased in NIDDM subjects; (2) SLC rates correlated weakly with serum triglyceride concentrations; (3) platelet sodium-hydrogen exchange Vmax and K(m) for extracellular sodium and platelet buffering capacity did not differ between diabetic and nondiabetic groups; and (4) there was no significant relationship between platelet Na+/H(+)-exchange kinetics and any of the cardiovascular risk factors studied.

Adult↗