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Biomedical subjects

F Gutierrez

Publications and source records attributed to F Gutierrez.

At least 19 recordsLinked to original sources
PubMed2005

Theoretical study of Ln(III) complexes with polyaza-aromatic ligands: geometries of [LnL(H2O)n]3+ complexes and successes and failures of TD-DFT.

The accuracy and the usefulness of density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations for the theoretical study of Ln (La, Eu, Lu) complexes have been investigated. The geometries calculated at the DFT level for [Ln(H2O)nL]3+ complexes have been successfully compared with crystallographic data. TD-DFT is able to offer valuable insights into VUV spectra of lanthanide complexes. However, the results obtained on the largest ligand (i.e., 2,4,6-tri-(pyridin-2-yl)-1,3,5-triazine (Tptz)) have to be considered as a failure of TD-DFT.

Journal Article↗
PubMed2004

Aerobic biological treatment of leachates from municipal solid waste landfill.

The main objective of the study was to improve chemical oxygen demand (COD) elimination by secondary biological treatment from leachate of municipal solid waste landfill. This effluent was a supernatant liquid obtained after physicochemical processes and coagulating with Al3+ followed by ammoniacal stripping. First, respirometric assays were carried out to determine the substrate biodegradability. Specific sludge respiration rate (R(s)) vs. concentration of substrate (S), showed an increasing specific rate of assimilation of substrate (Rs), which reached the highest value, when the substrate concentration (COD) was between 75 and 200 mg O2 L(-1). Second, continuous experiments were made in an aerobic digester to test the previous respirometric data and the results showed removal efficiency of COD between 83 and 69%, and a substrate assimilation rate between 1.3 and 3.1 g COD g(-1) volatile suspended solids d(-1).

Bacteria, Aerobic↗
PubMed2000

Propachlor removal by Pseudomonas strain GCH1 in an immobilized-cell system.

A bacterial strain capable of growing on propachlor (2-chloro-N-isopropylacetanilide) was isolated from soil by using enrichment and isolation techniques. The strain isolated, designated GCH1, was classified as a member of the genus Pseudomonas. Washed-cell suspensions of strain GCH1 accumulated N-isopropylacetanilide, acetanilide, acetamide, and catechol. Pseudomonas strain GCH1 grew on propachlor with a generation time of 4.2 h and a rate of substrate utilization of 1.75 +/- 0.15 micromol h(-1). Gene expression did not require induction but was subject to catabolite expression. Acetanilide was a growth substrate with a yield of 0.56 +/- 0.02 mg of protein micromol(-1). GCH1 strain cells were immobilized by adsorption onto a ceramic support and were used as biocatalysts in an immobilized cell system. Propachlor elimination reached 98%, with a retention time of 3 h and an initial organic load of 0.5 mM propachlor. The viability of immobilized cells increased 34-fold after 120 days of bioreactor operation.

Acetamides↗
PubMed1998

Prevalence of Vestibulocochlear Diseases in 4,825 Patients.

A study of the prevalence of vestibulocochlear disorders in 4,825 patients showed that these disorders occurred during middle age and mostly affected women. The most frequent pathologies are vascular labyrinthitis, emotional disturbance, and the cervical syndrome. The study also demonstrated that each disease has a preferential age group, which varies according to the gender.

Journal Article↗
PubMed1995

Oral feeding after total laryngectomy for endolaryngeal cancer.

There is still no agreement about the beginning of oral feedings after total laryngectomy. Some authors begin routine feedings on the 3rd postoperative day, while others delay oral feedings until 12-14 days after surgery. The present study was devised as a prospective randomized clinical trial concerning beginning oral feedings on the 7th or 14th postoperative day in 35 patients following total laryngectomy as treatment for endolaryngeal cancer. There were no differences in risk factors present in either group. Only two pharyngocutaneous fistulae occurred in the overall series (5.7%), with both appearing in the 7-day group and developing on the 18th and 20th postoperative days respectively. There were no statistically significant differences in fistula formation between the two groups (P = 0.49). We conclude that it is not necessary to delay oral feedings more than 7 days in patients without suture line tension.

Aged↗
PubMed1994

Delineation of determinants of left ventricular early filling. Saline versus blood infusion.

BACKGROUND: Left atrial pressure (LAP) is often believed to play a dominant role in the determination of left ventricular (LV) early diastolic filling. In a previous study we found no significant relation between LAP and LV early filling velocity (E) but found instead a relation between E and two determinants of LV myocardial shortening (contractility and afterload). To determine if such disparate results may be related to the data ranges of the independent variables in a given population of animals, we took advantage of the differential hemodynamic effects of two modes of volume expansion: saline and whole blood. METHODS AND RESULTS: Eighteen closed-chest anesthetized dogs were instrumented with micromanometers for measurement of LV, left atrial, and aortic pressures. LV volumes were obtained with use of contrast ventriculography, pressures by micromanometry, and transmitral flow-velocity by Doppler echocardiography. After obtaining baseline measurements, group 1 (n = 9) received rapid infusion of 500 to 650 mL of saline over 10 minutes, and group 2 (n = 9) received the same volume infusion of whole blood. In terms of two known determinants of E, infusion of saline resulted in a significant increase in LAP at the moment of mitral valve opening (X1) (1.5 +/- 0.9 to 5.7 +/- 1.4 mm Hg; P < .05) and a moderate decrease in the pressure decay rate during isovolumic relaxation (tau 1/2) (22.9 +/- 2.4 to 26.3 +/- 3.5 milliseconds; P < .05). When these two factors were entered together into a multiple regression analysis with E as the dependent variable, the overall correlation was found to be significant (R = .722; P < .008), with both independent variables contributing significantly to the relation. When factors related to myocardial shortening (afterload and contractility) were added to this relation, they did not significantly improve the prediction of E. Like saline, whole blood infusion augmented X1 (1.6 +/- 2.4 to 8.8 +/- 3.2 mm Hg; P < .05) and tau 1/2 (21.5 +/- 2.6 to 32.0 +/- 6.3 milliseconds; P < .05) but also significantly increased LV afterload as measured by aortic diastolic pressure (91 +/- 10 to 110 +/- 12 mm Hg; P < .05). Multiple regression analysis of X1 and tau 1/2 with E again revealed a significant relation (R = .761; P < .002), with both independent variables contributing significantly to the relation. However, in this case, addition of contractility and afterload to the regression significantly improved the relation (R = .909; P < .001), with all four independent variables now contributing significantly to the prediction of E. CONCLUSIONS: Combined with our previous results, this study indicates the degree to which experimental methods can have an impact on the delineation of the determinants of a phenomenon as complex as LV early diastolic filling. Which independent variables emerge as primary determinants can be strongly influenced by the experimenter's choice of experimental design and manipulations. Specifically, experiments using volume infusion to delineate the responses of the cardiovascular system to variations in loading must allow for the hemodynamic changes that are inherent in the choice of infusate and infusion technique, especially when those interventions may significantly alter blood oxygen-carrying capacity and, in turn, differentially modify factors that affect the magnitude of the early diastolic transmitral pressure gradient.

Animals↗
PubMed1994

Relationship between immune complex and total hemolytic complement in endolymphatic hydrops.

Recently there has been considerable investigation into the relationship of the immune system and immune disorder to Meniere's disease. Immunoglobulin G (IgG) antibody and complement are both present in endolymphatic fluid and it is possible that endolymphatic hydrops is due to immune complex. The authors' results show that patients with endolymphatic hydrops had elevated levels of circulating immune complex (CIC) of IgG (24.80 micrograms/mL). The levels of functional complement activity (CH50) were significantly lower in patients (249.7 HU) than in controls. Circulating levels of CIC and CH50 were positively correlated. Immunoglobulin G, immunoglobulin M (IgM), and subpopulation of B lymphocytes were elevated, but there was no alteration in subpopulations of T-helper, T-suppressor, and natural killer (NK) cells in peripheral blood.

Adult↗
PubMed1994

Scurvy resembling cutaneous vasculitis.

Various conditions can imitate cutaneous vasculitis. Scurvy is a less appreciated cause of rash that can resemble vasculitis. Three patients were referred to our rheumatology service for "vasculitis," who subsequently were found to have scurvy. Findings included a purpuric skin rash, myalgias, and malaise. The patients had low vitamin C levels and findings on skin biopsy specimens indicative of scurvy. The three patients were on idiosyncratic diets deficient in vitamin C, and the two patients who allowed us to administer vitamin C therapy improved clinically. We emphasize the importance of a careful dietary history. Early recognition of scurvy is important because it can be treated specifically, and toxic treatment of vasculitis can be avoided.

Adult↗
PubMed1992

Changes in immunologic response in tonsillectomized children. I. Immunosuppression in recurrent tonsillitis.

The possible immunoregulatory role of the tonsils was studied by determining immunoglobulins IgG, A, M, E and factors C'3, C'4 and PFB of the complement system before and after tonsillectomy. The synthesis in vitro of IgG and IgM by lymphocytes stimulated with pokeweed mitogen was also measured. There were statistically significant differences between pre and post-operative levels of serum IgG, IgA and IgM, which decreased after surgery. Practically no change in the mean values of IgE and no significant differences in the levels of serum C'3, C'4, and PFB, were found. The in-vitro synthesis of both immunoglobulins (IgG, IgM) by lymphocytes increased significantly after tonsillectomy. Our results suggest that not only does tonsillectomy have no counterproductive effect on the immune system, but that, on the contrary, it seems to improve the immune response, since it appears to unblock the suppression to which the immune system was subject.

Child↗
PubMed1992

Changes in immunological response in tonsillectomized children. II. Decreased cellular response.

The immunological cellular response was studied in 22 children aged between 5 and 10 years. One week before and one month after tonsillectomy, the mitogenic response to phytohaemagglutinin (PHA), concanavalin (ConA) and pokeweed mitogen (PWM) was tested. Our results showed statistically significant decreases in stimulation index (SI) to PHA, ConA and PWM after tonsillectomy. This suggests that the tonsils may influence the cellular immune status in children. The higher level of preoperative activity in children with recurrent tonsillitis could be understood as the result of stimulation of lymphocytes by bacteria.

Child↗
PubMed1991

Evaluation of lymphocyte activation by flow cytometric determination of interleukin-2 (CD25) receptor.

Lymphocyte response to mitogens is a habitually-used test in the evaluation of the immune system. The usual method with [3H]thymidine yields results which are difficult to interpret. In our search for an alternative, we examined the feasibility of determining T lymphocyte activation by measuring interleukin-2 receptor (CD25) expression with flow cytometry. We found a good correlation between CD25 molecule expression and the dose of phytohemagglutinin, however, there was no correlation between disintegrations per minute produced by [3H]thymidine uptake and the percentage of CD25 expressed by cells.

Adult↗
PubMed1990

Congenital tricuspid valve stenosis with atrial septal defect and left anterior fascicular block.

Congenital tricuspid valve stenosis in the absence of other valvular abnormalities is rare. In this report we describe a patient with congenital tricuspid valve stenosis, ostium secundum atrial septal defect, and electrocardiographic left anterior fascicular block, who presented with paradoxical emboli. This case, as well as previous case reports, suggests that congenital tricuspid stenosis with ostium secundum atrial septal defect is associated with left anterior fascicular block.

Adult↗
PubMed1990

Characterization of regional diastolic pressure gradients in the right ventricle.

Regional intraventricular pressure gradients exist in the left ventricle (LV) during both the early and late filling phases of diastole. These regional pressure gradients comprise a fundamental component of the mechanism of normal LV filling. To determine whether similar diastolic pressure gradients also occur in the right ventricle (RV), we measured right atrial (RA) and RV regional pressures with use of micromanometers in six anesthetized, closed-chest dogs. Tricuspid flow velocity was recorded with use of transesophageal Doppler echocardiography, and right ventriculograms were obtained with contrast angiography. As in the LV, the maximum RA-RV pressure gradient during early diastole was consistently greater if RV pressure was measured near the apex than in the inflow tract (1.6 +/- 0.5 versus 0.8 +/- 0.4 mm Hg). The area of reversed pressure was also found to be significantly greater in the apex than in the inflow tract (72 +/- 43 versus 8 +/- 6 mm Hg.msec). However, unlike the LV, the lowest minimum pressure was usually recorded in the RV outflow tract, resulting in a significantly increased RA-RV outflow tract pressure gradient compared with the RA-RV apex pressure gradient (2.5 +/- 0.8 versus 1.6 +/- 0.5 mm Hg). Analysis of right ventriculograms indicates marked narrowing of the RV outflow tract at end systole in all six animals, suggesting that an end-systolic deformation in this region is the likely mechanism for production of low early diastolic pressure in this region. During atrial contraction the RV regional pressure gradient pattern was similar to the LV pattern: the RV a-wave ascent occurred earlier in the inflow tract and later in the apex. A-wave ascent appeared to occur almost simultaneously in the apex and outflow tract. In the six animals, Doppler-derived peak tricuspid flow velocity during early diastole was 35 +/- 6 cm/sec. Early tricuspid flow acceleration (393 +/- 101 cm/sec2) was found to be significantly greater than deceleration of flow (182 +/- 59 cm/sec2). Comparison of tricuspid pressure-flow data with mitral pressure-flow data previously obtained in our laboratory indicates that the driving pressure gradient across the tricuspid valve is significantly less than across the mitral. This pressure difference corresponds to differences in acceleration and peak flow found across the two valves. Consideration of these physiological patterns of RV diastolic intraventricular pressure and their relation to filling has important implications with regard to the development of indexes that characterize diastolic pressure-flow relations and provides physiological insight relating to the location of ventricular restoring forces.

Animals↗
PubMed1990

HIV associated arthropathy: HIV antigen demonstration in the synovial membrane.

Light and electron microscopic studies were performed on the synovial membranes of 5 patients with HIV associated arthropathy. An immunoperoxidase technique with the use of monoclonal antibodies against CD4, CD8, B and DR lymphocytes, and HIV p24 antigen was also used. Mild to moderate nonspecific proliferative changes and increased vascularity of the subsynovial space were seen. Electron dense deposits and viral-like particles were not observed. Immunohistochemical staining revealed HIV p24 positive staining in cells of the synovial lining layer and in the mononuclear cells of the subsynovial space. CD4, CD8, with predominance of CD8, and B and DR cells were also present. The presence of HIV p24 antigen may be indicative of a role, yet to be defined, in the pathogenesis of HIV associated rheumatic disorders.

Acquired Immunodeficiency Syndrome↗