PubMed Health⌕ Search

Biomedical subjects

M Ramirez

Publications and source records attributed to M Ramirez.

At least 37 records · Page 2Linked to original sources
PubMed2003

Role of long-chain polyunsaturated fatty acids in infant nutrition.

OBJECTIVE: To review briefly the influence of dietary long-chain polyunsaturated fatty acids (LC-PUFA) on tissue composition and functionality in early infancy. Moreover, the influences of LC-PUFA sources on plasma composition as well as the effects of these fatty acids on intestinal repair after malnutrition are discussed. RESULTS: Human milk not only supplies essential fatty acids but also contains up to 2% of the total fatty acids as LC-PUFA, of which arachidonic acid (AA) and docosahexaenoic acid (DHA) are considered the most important. Plasma and erythrocyte levels of both AA and DHA are decreased in infants fed artificial standard milk formulae. However, the supplementation of formulae with these fatty acids in amounts close to that of human milk leads to tissue LC-PUFA patterns similar to those of breast-fed infants. However, the bioavailability of LC-PUFA depends on the typical LC-PUFA source; egg phospholipids increases both AA and DHA in plasma phospholipids and HDL more than a mixture of tuna and fungal triglycerides. CONCLUSIONS: Dietary LC-PUFA affects positively the growth and development of the infant and ameliorates the visual and cognitive functions, particularly in preterm infants. Likewise, LC-PUFA improves intestinal repair in severe protein-energy malnutrition; therefore, its qualitative and quantitative dietary supply should be considered.

Dietary Fats, Unsaturated↗
PubMed2003

Macrolide resistance in Streptococcus pneumoniae isolated from patients with community-acquired lower respiratory tract infections in Portugal: results of a 3-year (1999-2001) multicenter surveillance study.

A nationwide multicenter study (including 31 laboratories) of the antimicrobial susceptibility of 1210 Streptococcus pneumoniae isolates from patients with community-acquired lower respiratory tract infections (LRTI) was carried out over 3 years (1999-2001) in Portugal. Testing of all isolates was undertaken in a central laboratory. Overall macrolide resistance was 13.1%. Decreased susceptibility to penicillin was 24.5% (15.5% low-level and 9.0% high-level resistance). Taken into consideration, the resistance rates reported in a previous surveillance study of 1989-1993, a six-fold increase of erythromycin resistance in the last decade was documented. Resistance to erythromycin, clarithromycin, and azithromycin was higher in pediatric patients than in adults. The overwhelming majority (82.3%) of macrolide-resistant isolates were multidrug resistant, although 44.9% were fully susceptible to penicillin. Most macrolide-resistant isolates (80.4%) showed the MLSB phenotype (76.6% MLSB-constitutive resistance, and 3.8% MLSB-inducible resistance) and were also resistant to clindamycin, tetracycline, and co-trimoxazole. The M phenotype was seen in 19.6% isolates and these had MIC90 values of 8 mg/L for erythromycin and clarithromycin, and of 12 mg/L for azithromycin. The clinical significance of macrolide resistance in the management of LRTI is discussed. Because of the specific situation concerning macrolide resistance described in S. pneumoniae, careful use of macrolide antibiotics in therapy and cautious monitoring of macrolide resistance should be continued in Portugal.

Adult↗
PubMed2003

Serotyping Streptococcus pneumoniae by multiplex PCR.

The capsule is a major virulence factor of pneumococci, and it was shown that some capsular variants are associated with antimicrobial resistance and certain types of disease. Moreover, pneumococcal capsular typing has received renewed interest since the availability of conjugate vaccines, which include serotypes frequently associated with pediatric disease. Our aim was to develop a simple, reliable, and economical method for detecting epidemiologically important serotypes present in the proposed 11-valent conjugate vaccine. We designed primers based on the sequences available for the capsular types 1, 3, 4, 6B, 14, 18C, 19F, 19A, and 23F and combined them into seven multiplex PCRs. The method involves streamlined DNA template preparation and agarose gel electrophoresis to analyze the amplification products. A total of 446 pneumococci selected from among isolates colonizing the nasopharynx of children attending day care centers in Lisbon, Portugal, were typed both by conventional immunological techniques and by multiplex PCR. Capsular types identified by the PCR method invariably produced results concordant with the conventional serotyping technique. Even when the method presented does not fully type an isolate, the PCR data can guide the experimenter when using immunological serotyping. Multiplex PCR for the analysis of pneumococci provides an accurate, expeditious, and cost-effective way of reducing the number of strains that have to be serotyped by conventional immunological techniques.

Bacterial Capsules↗
PubMed2003

Seismic, structural, and individual factors associated with earthquake related injury.

BACKGROUND: Earthquakes cause thousands of deaths worldwide every year, and systematic study of the causes of these deaths can lead to their prevention. Few studies have examined how multiple types of risk factors are related to physical injury during an earthquake. METHODS: A population based case-control study was conducted to examine how individual characteristics, building characteristics, and seismic features of the 1994 Northridge, California, earthquake contributed to physical injury. Cases included fatal and hospital-admitted injuries caused by the earthquake. Controls were drawn from a population based phone survey of county residents. Cases were individually matched to two sets of controls: one matched by age and gender and one matched by location at the time of the earthquake. RESULTS: Individuals over age 65 had 2.9 times the risk of injury as younger people (95% confidence interval (CI) 1.2 to 7.4) and women had a 2.4 times greater risk than men (95% CI 1.2 to 5.1). Location in multiple unit residential and commercial structures each led to increased injury risk compared with single unit residential structures, but the exact estimate varied depending on the control group used. With every increase in ground motion of 10%g, injury risk increased 2.2 times (95% CI 1.6 to 3.3). CONCLUSIONS: Controlling for other factors, it was found that individual, building, and seismic characteristics were independently predictive of increased injury risk. Prevention and preparedness efforts should focus on each of these as potential points of intervention.

Adolescent↗
PubMed2002

Effects of dehydration on renal aminopeptidase activities in adult male and female rats.

Aminopeptidases (APs) are important regulators of peptides directly involved in water homeostasis such as angiotensins (Ang) and vasopressin (AVP). Sex differences in water balance and differences in the effects of gonadal steroids on osmotic stimulation of vasopressin secretion have been reported. Since sex steroids may be involved, the gonadotropin response to osmotic stimuli may be different between males and females. The purpose of this study was to determine the behavior of angiotensinases, vasopressin-degrading activity and gonadotropin-releasing hormone (GnRH)-degrading activity in the cortex and medulla of the kidney of dehydrated male and female rats. In the renal cortex, our results demonstrated an increase in Ang III-degrading activity in dehydrated males but not in females. This response may lead to an increased formation of Ang IV. This occurs with an increase in AspAP activity (which metabolizes Ang I to des-Asp(1)-Ang I), with no changes in Ang II-degrading activity and also with increased levels of AVP-degrading activity in dehydrated animals. These results may suggest an increased cortical blood flow due to enhanced formation of Ang IV together with reduced availability of the vasoconstrictor agents Ang II and AVP in the renal cortex of dehydrated males. The results obtained in the renal medulla suggest the inhibition of the metabolism of Ang I to des-Asp(1)-Ang I, together with a reduced metabolism of Ang II and AVP in dehydrated males but not in females. These results suggest a prolonged action of Ang II and AVP, which could stimulate sodium and water reabsorption in the medulla of dehydrated males. Changes in APs after dehydration occur preferentially in males, which may explain in part the reported sex differences in water homeostasis. The present results suggest a physiologically relevant role for AP activities in water homeostasis.

Aging↗
PubMed2002

Characterization of wastewater and solids odors using solid phase microextraction at a large wastewater treatment plant.

A simple and reliable technique has been developed and used to detect odorous gases, i.e. propionic and butyric acids, carbon disulfide, dimethyl sulfide, dimethyl disulfide, and trimethylamine, emitted from various materials generated by the wastewater treatment process. The method detection limits are in the low ppb range and comparable to the odor threshold for human detection. In this study solid phase microextraction (SPME) was employed to characterize and quantify odorous compounds in the headspace over samples collected from various unit processes at the District of Columbia Wastewater Treatment Plant, Washington DC, USA. The patterns of odorous chemicals released from wastewater influent, thickened sludge, dewatered sludge and biosolids were evaluated. Volatile reduced sulfurs were more prevalent in samples collected from downstream processes and corresponded with decreased oxidation-reduction potential (ORP) conditions. Volatile fatty acids were consistently identified in the primary gravity thickeners, while trimethylamine could only be detected from biosolids after the post-liming process.

Chemical Phenomena↗
PubMed2001

Dermal and pulmonary inflammatory disease in E-selectin and P-selectin double-null mice is reduced in triple-selectin-null mice.

In the initial phase of an inflammatory response, leukocytes marginate and roll along the endothelial surface as a result of adhesive interactions between molecules on the endothelial cells and leukocytes. To evaluate the role of the 3 selectins (E, L, and P) in leukocyte rolling and emigration, a null mutation for L-selectin was introduced into previously described embryonic stem cells with null mutations in the genes for both E-selectin and P-selectin (E/P double mutants) to produce triple-selectin-null mice (E-selectin, L-selectin, and P-selectin [E/L/P] triple mutants). Triple-selectin homozygous mutant mice are viable and fertile and only rarely develop the severe mucocutaneous infections or pulmonary inflammation characteristic of E/P double-mutant mice. Surface expression of L-selectin was undetectable in triple-mutant mice on fluorescence-activated cell-sorter analysis of peripheral neutrophils. Pathological studies revealed moderate cervical lymphadenopathy and lymphoplasmacytic infiltrate, but these were less extensive than in E/P double-mutant mice. Neutrophil emigration during thioglycolate-induced peritonitis was significantly reduced at 4, 8, and 24 hours (35%, 65%, and 46% of wild-type values, respectively). Intravital microscopy of the cremaster muscle revealed almost no rolling at times up to 6 hours after exteriorization, with or without addition of tumor necrosis factor alpha. The small amount of residual rolling was dependent on alpha(4)-integrin. The occurrence of skin and pulmonary disease in E/P double-mutant mice but not E/L/P triple-mutant mice suggests that deficiency of L-selectin alters the inflammatory response in E/P mutants. (Blood. 2001;98:727-735)

Animals↗
PubMed2001

Genome screening for linkage disequilibrium in a Costa Rican sample of patients with bipolar-I disorder: a follow-up study on chromosome 18.

Linkage disequilibrium (LD) methods offer great promise for mapping complex traits, but have thus far been applied sparingly. In this paper we describe an LD mapping study of severe bipolar disorder (BP-I) in the genetically isolated population of the Central Valley of Costa Rica. This study provides the first complete screen of a chromosome for a complex trait using LD mapping and presents the first application of a new LD mapping statistic (ancestral haplotype reconstruction (AHR)) that evaluates haplotype sharing among affected individuals. The results of this chromosome-wide analysis are instructive for genome-wide LD mapping in isolated populations. Furthermore, the analysis continues to support a possible BP-I locus on 18pter, suggested by previous analyses in this population. Evidence for a possible BP-I locus on 18q12.2 is also described.

Bipolar Disorder↗
PubMed2001

Expression, purification, and biophysical characterization of the BRCT domain of human DNA ligase IIIalpha.

The C-terminal regions of several DNA repair and cell cycle checkpoint proteins are homologous to the breast-cancer-associated BRCA-1 protein C-terminal region. These regions, known as BRCT domains, have been found to mediate important protein-protein interactions. We produced the BRCT domain of DNA ligase IIIalpha (L3[86]) for biophysical and structural characterization. A glutathione S-transferase (GST) fusion with the L3[86] domain (residues 837-922 of ligase IIIalpha) was expressed in Escherichia coli and purified by glutathione affinity chromatography. The GST fusion protein was removed by thrombin digestion and further purification steps. Using this method, (15)N-labeled and (13)C/(15)N-double-labeled L3[86] proteins were prepared to enable a full determination of structure and dynamics using heteronuclear NMR spectroscopy. To obtain evidence of binding activity to the distal BRCT of the repair protein XRCC1 (X1BRCTb), as well as to provide insight into the interaction between these two BRCT binding partners, the corresponding BRCT heterocomplexes were also prepared and studied. Changes in the secondary structures (amount of helix and sheet components) of the two constituents were not observed upon complex formation. However, the melting temperature of the complex was significantly higher relative to the values obtained for the L3[86] or X1BRCTb proteins alone. This increased thermostability imparted by the interaction between the two BRCT domains may explain why cells require XRCC1 to maintain ligase IIIalpha activity.

Amino Acid Sequence↗
PubMed2001

Prevalence of depression and depression recognition in nursing homes.

BACKGROUND: The aim of this study was to estimate the prevalence of depression among nursing home residents, and the extent of depression recognition among nursing home staff. Random samples totaling 319 nursing home residents, drawn from a simple random sample of six downstate New York nursing homes were evaluated psychiatrically for depression. Samples of nurse aides, nurses and social workers also assessed the same residents for the presence of depressive symptomatology. METHOD: Psychiatrists assessed residents using the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) criteria. Depression measures used were the Cornell Scale for Depression in Dementia, the Feeling Tone Questionnaire, the Hamilton Depression Rating and the Structured Clinical Interview for DSM-III-R Personality Disorders Scale. Nursing and social services staff assessed residents using Depression Recognition Measures. RESULTS: Based on psychiatric evaluation, the prevalence estimate for probable and/or definite major depressive disorder among testable subjects was 14.4% (95% CI of 10.6%-19.3%); 15.4% were not able to be assessed due to their refusal, impairment of consciousness, or severe physical illness. The estimate for minor depression was 16.8% (95% CI of 12.6%-21.9%). The prevalence of significant depressive symptomatology (including the category of possible depression) was 44.2% (95% CI of 38.2%-50.3%). The corresponding estimates of any depression were 19.7% for social workers, 29% for nurses and 32.1% for nurse aides. CONCLUSIONS: The prevalence of depressive disorders among nursing home residents is high; depression recognition is relatively low, with only 37%-45% of cases diagnosed by psychiatrists recognized as depressed by staff. A structured Depression Recognition Scale increased the rates of recognition (sensitivity of staff ratings) to 47%-55%, demonstrating the utility of the scale in increasing awareness of symptomatology.

Age Distribution↗
PubMed2001

Study of the influence of electroconvulsive therapy on the regional cerebral blood flow by HMPAO-SPECT.

STUDY OBJECTIVE: The aim of this preliminary study is to investigate the regional blood flow in response to ECT (electroconvulsive therapy) and to identify any responsive-pattern to the treatment. METHODS STUDY DESIGN: Single longitudinal prospective study of cohorts. SUBJECTS: For this preliminary study ten patients, female sex, mean age 70.8 years with major mood disorder (CID-10 investigation criteria) were studied after signature consent. INTERVENTIONS: The intervention consisted in the administration of bilateral brief pulse ECT three times a week, during 6 to 12 sessions according to the standards of the Psychiatric Department of the Santiago Hospital in Victoria. MEASUREMENT: Clinical evaluation of depression was evaluated by Hamilton Depression Scale, Montgomery and Asberg Scale, Newcastle Scale and regional cerebral blood flow (rCBF) using the HMPAO-SPECT. RESULTS: The pattern of distribution on the regional cerebral flow during the ECT showed changes from the basal pattern in all patients. All patients had a relative increased perfusion of the temporal lobes and basal ganglia. Other changes from the basal study were areas of decreased perfusion of the occipital lobe (6 patients) and parietal lobe (3 patients). CONCLUSIONS: Brain perfusion SPECT study of the patients with major depression shows changes during ECT. Further analysis are needed to understand the relationship between mechanisms of treatment and recovery in affective illness.

Aged↗
PubMed2001

Human CD34+ cell preparations contain over 100-fold greater NOD/SCID mouse engrafting capacity than do CD34- cell preparations.

OBJECTIVE: The CD34 cell surface marker is used widely for stem/progenitor cell isolation. Since several recent studies reported that CD34(-) cells also have in vivo engrafting capacity, we quantitatively compared the engraftment potential of CD34(+) vs CD34(-) cell preparations from normal human placental/umbilical cord blood (CB), bone marrow (BM), and mobilized peripheral blood (PBSC) specimens, using the nonobese diabetic/severe combined immunodeficient (NOD/SCID) mouse model. METHODS: CD34(+) and CD34(-) cell preparations were purified by four different approaches in 14 individual experiments involving 293 transplanted NOD/SCID mice. In most experiments, CD34(+) cells were depleted twice (CD34(=)) in order to obtain efficient depletion of CD34(+) cells from the CD34(-) cell preparations. RESULTS: Dose-dependent levels of human hematopoietic cells were observed after transplantation of CD34(+) cell preparations. To rigorously assess the complementary CD34(-) cell preparations, cell doses 10- to 1000-fold higher than the minimum dose of the CD34(+) cell preparations necessary for engraftment were transplanted. Nevertheless, of 125 NOD/SCID mice transplanted with CD34(-) cell preparations purified from the same starting cells, only six mice had detectable human hematopoiesis, by flow cytometric or PCR assay. CONCLUSIONS: CD34(-) cells provide only a minor contribution to hematopoietic engraftment in this in vivo model system, as compared to CD34(+) cells from the same samples of noncultured human cells. Hematopoiesis derived from actual CD34(-) cells is difficult to distinguish from that due to CD34(+) cells potentially contaminating the preparations.

Animals↗
PubMed2001

Transcranial magnetic stimulation coregistered with MRI: a comparison of a guided versus blind stimulation technique and its effect on evoked compound muscle action potentials.

INTRODUCTION AND METHODS: Compound muscle action potentials (CMAPs) elicited by transcranial magnetic stimulation (TMS) are characterized by enormous variability, even when attempts are made to stimulate the same scalp location. This report describes the results of a comparison of the spatial errors in coil placement and resulting CMAP characteristics using a guided and blind TMS stimulation technique. The former uses a coregistration system, which displays the intersection of the peak TMS induced electric field with the cortical surface. The latter consists of the conventional placement of the TMS coil on the optimal scalp position for activation of the first dorsal interossei (FDI) muscle. RESULTS: Guided stimulation resulted in significantly improved spatial precision for exciting the corticospinal projection to the FDI compared to blind stimulation. This improved precision of coil placement was associated with a significantly increased probability of eliciting FDI responses. Although these responses tended to have larger amplitudes and areas, the coefficient of variation between guided and blind stimulation induced CMAPs did not significantly differ. CONCLUSION: The results of this study demonstrate that guided stimulation improves the ability to precisely revisit previously stimulated cortical loci as well as increasing the probability of eliciting TMS induced CMAPs. Response variability, however, is due to factors other than coil placement.

Adult↗
PubMed2001

Streptococcus pneumoniae isolates with reduced susceptibility to ciprofloxacin in Spain: clonal diversity and appearance of ciprofloxacin-resistant epidemic clones.

Analysis of the pulsed-field gel electrophoretic profiles of 82 pneumococcal isolates with reduced susceptibility to ciprofloxacin (RSC) and of 90 co-occurring susceptible isolates indicates a considerable genetic diversity among isolates with RCS and points to a close relation between the two groups. This finding suggests that pneumococci with RCS emerge through independent mutational events.

Anti-Infective Agents↗
PubMed2000

Severe menorrhagia due to Glanzmann thrombasthenia treated with hydrothermal ablation.

Glanzmann thrombasthenia is a rare platelet disorder inherited as an autosomal recessive trait. Abnormal uterine bleeding is a common problem in women with the disease. Medical management may not always be effective and further treatment may be necessary. Two women underwent endometrial ablation with a continuous-flow circulating hydrothermal ablator. After follow-up of 12 and 18 months, both women remained without abnormal uterine bleeding.

Adolescent↗
PubMed2000

Clinical and economic comparison of allogeneic peripheral blood progenitor cell and bone marrow transplantation for acute lymphoblastic leukemia in children.

There is limited experience in the use of peripheral blood progenitor cells (PBPC) for allogeneic transplantation in children. In the present study we compared engraftment kinetics, incidence of acute and chronic graft-versus-host disease (GVHD) and the outcome and economic costs of allogeneic PBPCT vs BMT in children with ALL in a single institution. All children were transplanted in complete remission (CR) with a similar conditioning regimen and the same GVHD prophylaxis. Patients undergoing PBPCT achieved myeloid and platelet engraftment before patients undergoing BMT (P < 0.001). Platelet recovery was faster for the PBPCT group (P < 0.014 for 50 x 10(9)/l and P < 0.039 for 100 x 10(9)/l). Incidence and severity of acute and chronic GVHD were similar in both groups (acute grade 1-2: 9/13 for PBPCT vs 9/11 for BMT; chronic GVHD: 5/12 for PBPCT vs 3/8 for BMT). Hospital stay was shorter for the PBPCT than for the BMT group (28.8 days vs 42.9 days, respectively) and the PBPCT group used less clinical resources, resulting in overall lower cost for PBPCT (US $14,046) compared to BMT (US $19,840). There was no statistically significant difference in DFS between PBPCT and BMT (68.4% vs 50%, respectively).

Bone Marrow Transplantation↗