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Biomedical subjects

A Ramos

Publications and source records attributed to A Ramos.

At least 217 records · Page 12Linked to original sources
PubMed1995

Magnetic resonance imaging of the brain in systemic lupus erythematosus.

Magnetic resonance imaging (MRI) of the brain is a sensitive method to detect parenchymal tissue lesions. Its value in the diagnosis of central nervous system (CNS) lupus is disputed. To address this question, we have conducted an open and prospective study in a population of 44 SLE patients. We investigated 24 patients (mean age 33 +/- 13 yr) with past or active CNS lupus (group A) that included organic brain syndrome (12), migraine (8), focal neurological signs (7), seizures (2), myelopathy (1) and narcolepsy-cataplexy (1), and 20 patients (mean age 32 +/- 12 yr) without CNS lupus (group B). Health controls comprising nine females and one male aged 31 +/- 9 yr were also studied for comparison (group C). MRI was performed using sagittal T1-weighted images, axial and coronal spin density, and T2-weighted images. All scans were read blindly. Thirteen patients in group A and 10 in group B had well-identified lesions on sequences with long repetition time. Lesions were mostly multiple, small, punctate areas of increased signal at periventricular or subcortical white matter of both cerebral hemispheres. The number and location of lesions were not significantly different in both groups. None of the group C patients had MRI lesions. The presence of lesions was significantly associated with age at study and disease duration, but not with the presence of CNS lupus. In summary, MRI abnormalities are detected in neurologically asymptomatic SLE patients. Whether this represents subclinical brain involvement remains unknown.

Adolescent↗
PubMed1995

Code status decision-making in a nursing home population: processes and outcomes.

OBJECTIVES: To examine the clinical utility of prehospital code status discussions in a nursing home (NH) setting and the health care outcomes of the decisions made. Also to identify patient factors and other variables associated with these decisions. DESIGN: Retrospective uncontrolled observational study carried out through record review. SETTING: A single skilled-level teaching NH and its affiliated university hospital. PATIENTS: All of the 350 individuals who resided at the NH during a 2-year period. MAIN RESULTS: Code status decisions were routinely sought through discussion involving primary care physician/social worker teams and residents or surrogates of demented patients. Choices were made for 80% of the NH residents, most (73%) by surrogates and most (80%) for do-not-resuscitate (DNR) orders, usually within 10 weeks of NH admission. Neither short-term measures of NH care intensity nor hospital use changed after a DNR decision. Most (80%) hospital transfer records included code status documentation. At the NH, both the likelihood of decisions and their directions were associated with involvement by specific physician/social worker teams. Additionally, a dementia diagnosis, white race, and older age were associated with a nursing home DNR decision. At the hospital, a DNR order was associated with white race, the presence of nursing home DNR documentation in the transfer records, hospital attending care by certain NH physicians, and a terminal hospital stay. Hospital inpatient medical and surgical therapy use, except for intensive care procedures, was similar for DNR and non-DNR inpatients. Residents with DNR orders had a higher mortality rate, yet most survived at least 1 year after the order. In the short term, a DNR order had no impact on measured health care resource consumption, but, for those in the final months of life, in-patient hospital use was less for the DNR group, and most of these died at the nursing home. CONCLUSIONS: Prehospital code status decisions can be made effectively within the NH setting. Outside of medical intensive care, DNR orders have no impact on NH and hospital care intensity in the short term. In the final 6 months of life, however, hospital use is less for the DNR subgroup.

Advance Directives↗
PubMed1995

Enzyme Basis for pH Regulation of Citrate and Pyruvate Metabolism by Leuconostoc oenos.

Citrate and pyruvate metabolism by nongrowing cells of Leuconostoc oenos was investigated. (sup13)C nuclear magnetic resonance (NMR) spectroscopy was used to elucidate the pathway of citrate breakdown and to probe citrate or pyruvate utilization, noninvasively, in living cell suspensions. The utilization of isotopically enriched substrates allowed us to account for the end products derived from the metabolism of endogenous reserves. The effect of environmental parameters, e.g., pH, gas atmosphere, and presence of malate, on the end products of citrate utilization was studied. Approximately 10% of the citrate supplied was converted to aspartate which remained inside the cells. A metabolic shift with pH was observed, with acetoin production being favored at pH 4, whereas lactate and acetate production increased significantly at higher pH values. The information obtained with NMR was complemented with studies on the relevant enzyme activities in the metabolic pathway of citrate breakdown. The intracellular pH of the cells was strongly dependent on the external pH; this result, together with the determination of the pH profile of the enzymic activities, allowed us to establish the basis for pH regulation; lactate dehydrogenase activity was optimal at pH 7, whereas the acetoin-forming enzymes displayed maximal activities below pH 5. Citrate utilization was also monitored in dilute cell suspensions for comparison with NMR experiments performed with dense suspensions.

Journal Article↗
PubMed1995

Immunohistochemical correlation of steroid receptors and disease-free interval in 206 consecutive cases of breast cancer: validation of telequantification based on global scene segmentation.

Objective algorithms to evaluate immunocytochemistry in cytology and in histological sections are still under investigation. Clinical value, simplicity, robustness and adaptation to new technologies such as telemedicine and telequantification have to be taken into consideration. The present paper summarizes the experience of the immunoquantification of 206 cases diagnosed from 1990 to 1991, 36 clinical stage I cases, 110 stage II cases and 60 stage III cases. Initial clinical stage IV cases were excluded from the series. Quantification was done on frozen sections incubated with monoclonal estrogen and progesterone receptors (ER, PgR) by the peroxidase antiperoxidase (PAP) technique revealed with DAB. Automatic computerized measurements with a 550-nm filter were based on global scene segmentation, obtaining the parameters of percentage of positive area (pA) and immunoscore (ISC = sum i x pi), being the staining intensity (i) automatically evaluated in 5 grades multiple of the standard deviation (SD) of the control specimen (i x SD) stained with progressive haemathoxyline. Cut point of positive and negative specimens regarding ISC were obtained by semilogarithmic plot with biochemical receptor values (r = 0.73). The whole series showed a significant increase of negative specimens according to clinical stage and a higher number of PgR negative cases (44%) than ER negative cases (32%). The clinical relevance of the quantified parameters were evaluated by free interval disease survival curves being significant in the positive cutting point of ISC = 100 (ER P < 0.06; PgR P < 0.02) and the 40% negative area for the pA (ER P < 0.001; PgR P < 0.004). This quantification technique, which does not require individual cell segmentation, was reproducible at a distance (telequantification through high resolution videophones at 9600 bauds transmission rate; 55 cases). Coefficient of variation (CV) of the parameters in the original and transmitted cases were in the range of 0-5% in specimens with positive areas over 70%; less positive specimens require lower segmentation thresholds to get acceptable coefficients of variation. According to our results, immunohistochemical steroid receptor contents in breast cancer pathology, quantified by the technique of pixel integration, demonstrated the added value of the percentage of positive area in patient follow-up. Those having more than 40% of negative areas have recurrences mainly within the first year.

Adult↗
PubMed1995

[Importance of anaerobic bacteria in recurrent childhood non-streptococcal tonsillitis].

BACKGROUND: The presence of anaerobes in the oropharyngeal flora was already known, but they were infrequently involved in infections, except for specific diseases (abscesses, Vincent's angina). The involvement of anaerobes in more frequent by observed oropharyngeal diseases has been recently proposed. METHODS: We analyzed the tonsillar flora of 22 healthy children (control group) and 54 children diagnosed of recurrent tonsillitis. We compare the clinical response of children with recurrent tonsillitis to two treatments: penicillin, and penicillin plus metronidazole. RESULTS: We isolated Streptococcus pyogenes from 22.2% of children with tonsillitis, and did not isolate it from any healthy children. The rest of tonsillar flora was qualitatively similar in both groups. Both populations showed a high proportion of beta-lactamase-producer bacteria. In children from whom S. pyogenes was isolated, the response to the treatment was similar for both treatments. In those cases where S. pyogenes was not isolated, penicillin + metronidazole cured the 77.2% of children treated, but penicillin cured only 30% of cases. CONCLUSIONS: These results suggest that anaerobes might be involved, at least, in recurrent tonsillitis when S. pyogenes is not found, and justify further studies about the etiology and treatment of this disease.

Bacteria, Anaerobic↗
PubMed1995

[Hospital prevalence of kidney failure. Consequences and reflections for the planning of nephrology services].

A prospective prevalence study of Renal Failure (RF) in inhospital patients (creatinine > = 1.7 mg/dl) was carried out during March 1994, in two hospitals covering well defined and mutually exclusive populations. Cases were selected by screening all urea and creatinine blood tests performed in both laboratories, and registered in an individual form for daily follow-up of their nephrologic outcome. We registered 242 RF cases among 3525 patients admitted (6.8%), with an A.R.F. prevalence of 5.2%, 46% of all patients had a serum creatinine > 3 mg/dl and 71% were older than 65 years. In 55% RF was acquired inside the hospital. The most frequent cause of A.R.F. was pre-renal failure with 37%, followed by 32% of ischemic acute tubular necrosis and 13% toxic ATN. Nephrology was consulted in only 29% of all hospital RF cases. Only 17% of the RF patients were submitted to dialysis procedures, overall mortality was 31%, and 30% had normal renal function at discharge. Our results provide a data base to rethink the organization, staffing and role of nephrology departments inside general hospitals.

Female↗
PubMed1995

Psychological distress in mothers of preterm infants.

The purpose of this study was to identify infant and maternal characteristics that predict psychological distress among mothers of preterm infants admitted to the neonatal intensive care unit (NICU). Infant characteristics included birth weight, gestational age, and ventilatory support, and maternal characteristics included age, parity, and socioeconomic status. Mothers (n = 142) completed questionnaires including a demographic form, the Parental Stressor Scale, and the Symptom Checklist 90-R. In hierarchical regression analyses, maternal NICU-specific distress was more strongly predicted by infant characteristics [F(3,135) = 6.80, p < .05] with maternal variables covaried. Maternal general psychological distress was more strongly predicted by maternal characteristics [F(3,135) = 6.05, p < .05]) with infant variables covaried. Twenty-eight percent of mothers reported clinically significant psychological distress compared with 10% in a normative population. Psychological distress among mothers of preterm infants appears to be common and deserves clinical consideration. The use of standardized questionnaires as part of the assessment process may improve case identification and psychosocial service delivery in the NICU.

Adaptation, Psychological↗
PubMed1994

Peritrophic matrix of the black fly Simulium vittatum: formation, structure, and analysis of its protein components.

The peritrophic matrix (PM) (same as peritrophic membrane) is secreted by the midgut epithelium of insects and completely surrounds the ingested food. The PM is likely to influence disease transmission by hematophagous insects. As a prelude to a more detailed examination of PM function, we report on morphological and molecular studies of the PM type 1 (PM1) from Simulium vittatum. The blood meal induces major changes in epithelial cell morphology: cells become flattened, microvilli decrease dramatically in number, and organelles redistribute in the cytoplasma. The PM1 forms within minutes of the blood meal. After 6 h the PM1 has reached its maximum thickness (approximately 13 microns) and strength. Two-dimensional gel electrophoresis reveals two major PM1-specific proteins of 66 and 61 kDa. Synthesis of these PM1 proteins is likely to be induced by the blood meal, since they are not detectable prior to blood feeding. The time course of accumulation and disappearance of the PM1 proteins closely correlates with the appearance and disappearance of the PM1 itself.

Animals↗
PubMed1994

Anti-LFA-1 (CD11a) monoclonal antibody interferes with neonatal induction of tolerance to alloantigens.

The injection of (C57BL/6 x BALB/c)F1 spleen cells into newborn BALB/c mice results in the induction of a specific cytotoxic T lymphocyte (CTL) tolerance to the alloantigens. On the contrary, alloreactive CD4+ T cells persist in the host and are still able to activate autoreactive F1 B cells to produce autoantibodies. This state of "split tolerance" is closely associated with the development of a lupus-like autoimmune syndrome. The LFA-1 integrin plays a relevant role in homing, intercellular adhesion and tranduction of co-stimulatory signals in leukocytes. Because of the beneficial effects of anti-LFA-1 monoclonal antibodies (mAb) treatment in various models of organ transplantation and autoimmune disease, we have investigated if such a treatment could interfere with the induction of neonatal tolerance or the development of the autoimmune syndrome in F1 cell-injected newborn mice. For this purpose, BALB/c mice neonatally injected with F1 cells were treated from day 1 up to day 15 with a non-cytotoxic anti-LFA-1 (CD11a) mAb. Anti-LFA-1 mAb treatment interfered with the persistence of a stable chimerism and with the establishment of CTL tolerance, as shown by rejection of allogeneic skin grafts and F1 B cells, and by a normal in vitro CTL activity against the corresponding alloantigens. As a consequence, these mice did not develop the characteristic autoimmune features seen in close association with an effective induction of CTL tolerance to alloantigens. These results stress the importance of the interactions between LFA-1 and its ligands during the neonatal induction of tolerance to alloantigens.

Animals↗
PubMed1994

Growth of Phormidium sp. in aerobic secondary piggery waste-water.

The potential of a cyanobacterium Phormidium sp., for the tertiary treatment of piggery waste-water chemical oxygen demand > or = 3000 mg.l-1, using an aerobically stabilized secondary effluent, was studied. Batch cultures were carried out in 2-l glass reactors and in a 30-l glass-fibre carousel reactor. The nutrient removal efficiency as well as biomass production were compared in synthetic mineral medium and in different concentrations of aerobically stabilized piggery effluent. The best performance of Phormidium sp. occurred in diluted stabilized secondary effluent (1:1). Removal efficiencies were 100% for P-PO4(-3), 50% for N-NH4+ and 35% for N-NO3- in small-volume cultures; and 31% for P-PO4(-3), 100% for N-NH4+ and 70% for N-NO3- in an open carousel reactor. Biomass production on the aerobically stabilized effluent was six times higher in the 2-l reactors and 1.7 times higher in the carousel reactor when compared to the synthetic medium.

Aerobiosis↗
PubMed1994

Mixed cryoglobulinemia in a heroin addict.

Several forms of glomerulopathies have been described in patients who use intravenous heroin, including focal glomerulosclerosis, membranous nephropathy associated with chronic hepatitis B antigenemia, and immune complex proliferative glomerulonephritis. This report describes a patient who was a heroin addict for 15 years and who developed membranoproliferative glomerulonephritis and cutaneous vasculitis due to mixed cryoglobulinemia; he also had a positive hepatitis C virus (HCV) antibody. Recently, an association has been described between "essential" mixed cryoglobulinemia and chronic HCV infection, which has a high prevalence in intravenous drug addict population. It is possible that mixed cryoglobulinemia-associated glomerulonephritis, occurring with chronic HCV infection, came to be considered a major cause of renal disease in heroin abusers. The possibility that HCV infection can be responsible for other types of renal involvement in intravenous drug addicts deserves further attention.

Adult↗