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Biomedical subjects

A Albert

Publications and source records attributed to A Albert.

At least 91 records · Page 5Linked to original sources
PubMed1999

Factors determining the percentage of hypochromic red blood cells in hemodialysis patients.

UNLABELLED: Factors determining the percentage of hypochromic red blood cells determines iron status in hemodialysis patients. BACKGROUND: Determination of the percentage of hypochromic red blood cells (RBC; %HYPO) has been advocated as a sensitive index of functional iron deficiency during erythropoietin (EPO) therapy in hemodialyzed patients. METHODS: The significance of %HYPO in chronic renal failure was evaluated in 64 chronically hemodialyzed patients. The linear correlation was determined between %HYPO and 13 variables, including age, sex, weight, C-reactive protein (CRP), ferritin, transferrin (Tf), Tf saturation, soluble Tf receptor (sTfR), serum iron (SI), urea, parathormone, dialysis dose (Kt/V), dose of EPO administered (EPO), and absolute reticulocyte count. Multiple regression analyses were then performed to select the parameters that jointly provide the best prediction of %HYPO. RESULTS: Univariate analysis showed significant correlations between %HYPO and iron parameters (sTfR, Tf saturation, SI, and ferritin, in decreasing order), EPO, reticulocyte count, and CRP. Multivariate analysis yielded an equation showing that the variation of %HYPO is essentially associated with the combined changes in sTfR, CRP, and EPO dosage. CONCLUSIONS: %HYPO is a meaningful and inexpensive parameter that reflects the integrated effects of iron stores, inflammation, and erythropoietic stimulation on iron availability in hemodialyzed patients. Among iron exchange parameters, sTfR is the best predictor of %HYPO, followed by Tf saturation, SI, and ferritin.

Adult↗
PubMed1999

Pubertal growth as a determinant of adult height in boys with constitutional delay of growth and puberty.

In boys with constitutional delay of growth and puberty, adult height may be inconsistent with parental (target) height. We aimed at studying which period of growth was important to account for adult height being above or below target height. In this retrospective study, adult height measured after 20 years in 39 patients was compared with target height and height data obtained at about 6 and 12 years of age and at diagnosis of delayed puberty (mean 14.6 years). Twenty-eight patients were untreated while 11 received testosterone enanthate (50 or 100 mg/month for 6 months). The growth data from both groups were pooled since they were not different. On average, the adult height standard deviation score (-0. 6 +/- 0.8, mean +/- SD) was similar to target height (-0.5 +/- 0.6). There were, however, marked individual differences since adult height varied between 1.7 SD (11 cm) below target height and 1.4 SD (9.5 cm) above target height. Multiple regression analysis showed that the most significant determinant of the difference between adult height and target height was height catch up during puberty (p < 0.002). We conclude that the magnitude of height catch up during puberty is a significant determinant of adult height in boys with constitutional delay of growth and puberty. Thus, optimizing pubertal growth may be a relevant therapeutic aim for adult height in boys with short stature and delayed puberty. Copyrightz1999S. KargerAG,Basel

Adolescent↗
PubMed1999

A hyperphosphorylated form of RNA polymerase II is the major interphase antigen of the phosphoprotein antibody MPM-2 and interacts with the peptidyl-prolyl isomerase Pin1.

The monoclonal antibody MPM-2 recognizes a subset of M phase phosphoproteins in a phosphorylation-dependent manner. It is believed that phosphorylation at MPM-2 antigenic sites could regulate mitotic events since most of the MPM-2 antigens identified to date have M phase functions. In addition, many of these proteins are substrates of the mitotic regulator Pin1, a peptidyl-prolyl isomerase which is present throughout the cell cycle and which is thought to alter its mitotic targets by changing their conformation. In interphase cells, most MPM-2 reactivity is confined to nuclear speckles. We report here that a hyperphosphorylated form of the RNA polymerase II largest subunit is the major MPM-2 interphase antigen. These findings were made possible by the availability of another monoclonal antibody, CC-3, that was previously used to identify a 255 kDa nuclear matrix protein associated with spliceosomal components as a hyperphosphorylated form of the RNA polymerase II largest subunit. MPM-2 recognizes a phosphoepitope of the large subunit that becomes hyperphosphorylated upon heat shock in contrast to the phosphoepitope defined by CC-3, whose reactivity is diminished by the heat treatment. Therefore, these two antibodies may discriminate between distinct functional forms of RNA polymerase II. We also show that RNA polymerase II large subunit interacts with Pin1 in HeLa cells. Pin1 may thus regulate transcriptional and post-transcriptional events by catalyzing phosphorylation-dependent conformational changes of the large RNA polymerase II subunit.

Animals↗
PubMed1999

[Atypical primary biliary cirrhosis or autoimmune cholangitis?].

The term autoimmune cholangitis is used for a disease with clinical and pathological features of primary biliary cirrhosis (PBC), lack of anti-mitochondrial antibodies (AMA), presence of anti-nuclear antibodies (ANA), and good response to immunosuppresive therapy. The current knowledge of this condition is limited and it is not established whether or not it is a different syndrome from the CBP. We report a 51-year-old woman with chronic cholestasis, histological features of PBC, negative AMA and positive peripheral fluorescent ANA pattern, without response to prednisone.

Antibodies, Antinuclear↗
PubMed1998

External quality assessment (EQA) of Belgian clinical laboratories. The telematics paradigm.

Technology that enables communication between information systems has recently become cheaper and more powerful. It is therefore timely to consider the effects of the introduction of such techniques in external quality assessment (EQA) schemes on both users and organizers. Traditionally, results are returned to EQA organizers as hand-written numbers on structured forms. These data are then manually entered into a computer. The process is time-consuming, slow (as it depends on the postal service), prone to error at every transcription stage, and expensive, as clerical staff must be employed to input the data. Computer-to-computer communication allows this process to be improved. A telematics system for electronic data interchange has been developed for the Belgian EQA programme and it offers several advantages, such as the use of standardized semantics, expression of results in laboratory familiar units, possible interface with the Laboratory Information System, faster data analysis, shorter report time and long-term performance evaluation.

Belgium↗
PubMed1998

Relative value of clinical and transesophageal echocardiographic variables for risk stratification in patients with infective endocarditis.

BACKGROUND: Infective endocarditis remains a life-threatening disease, and its optimal management is of paramount importance. Transesophageal echocardiography (TEE) is useful for the diagnosis of endocarditis-induced lesions, but the prognostic significance of the method remains controversial. HYPOTHESIS: The purpose of this study was to relate clinical and TEE characteristics to the occurrence of mortality and/or systemic embolization in a consecutive series of 45 patients with a diagnosis of infective endocarditis. METHODS: All patients underwent at least one monoplane TEE. Clinical data, episodes of embolization, and echocardiographic characteristics were prospectively recorded. Stepwise logistic discriminant analysis was performed to identify the independent variables that best predicted three binary outcomes: systemic embolization, death, and systemic embolization and/or death. RESULTS: Twelve of the 45 patients (27%) died from the endocarditis. Significant univariate predictors of death were the presence of paravalvular abscess (p = 0.025), number of vegetations (p = 0.021), Staphylococcus aureus isolated in blood cultures (p = 0.002), medical treatment alone (p < 0.002), and systemic embolism (p < 0.001). In multivariate analysis, systemic embolism (chi 2 = 29.3; p < 0.01), echocardiographic evidence of paravalvular abscess (chi 2 = 5.6; p = 0.018), Staphylococcus aureus endocarditis (chi 2 = 5.5; p = 0.016), and medical treatment alone (chi 2 = 5.11; p = 0.024) emerged as optimal predictors of death. Systemic embolization occurred in 12 patients. Independent variables predicting systemic embolization were a total length of vegetations > 14 mm (p = 0.01), greater age (p = 0.02), and medical treatment alone (p = 0.03). When two or more vegetations were observed, the total length is the sum of the individual sizes. Independent risk factors for the development of systemic emboli and/or death as a combined end point were total length of vegetations on TEE (chi 2 = 6.4; p = 0.003) and medical treatment alone (chi 2 = 4.1; p = 0.047). CONCLUSIONS: High-risk patients may be identified by the combination of clinical variables and TEE characteristics.

Discriminant Analysis↗
PubMed1998

Reproducibility and diagnostic sensitivity of ultrasonometry of the phalanges to assess osteoporosis.

OBJECTIVE: The present study was designed to assess the reproducibility and the diagnostic sensitivity of the amplitude-dependent speed of sound (SoS) at the distal metaphysis of the proximal phalanges. METHOD: Fourteen presumably healthy volunteers were repeatedly measured every 6 weeks for approximately 6 months in order to assess the reproducibility of the SoS of the phalanges. We recruited 91 post-menopausal women, aged 55-75 years, who were divided in three groups according to their lumbar bone mineral density (BMD) and the existence of prevalent vertebral fractures. The objective was to evaluate the diagnostic sensitivity of SoS measurements. We used DBM Sonic 1200 equipment, and assessed the velocity at which US cross the phalanx in a lateral-medial direction. In post-menopausal women, BMD was measured by dual energy X-ray absorptiometry (DXA) at the level of the lumbar spine, the total zone of the non-dominant hip and the femoral neck zone of the non-dominant hip. RESULTS: The precision of the SoS measurements was 0.71+/-0.05% (mean+/-S.E.M) whereas the reproducibility was 0.95+/-0.06%. Subjects with low BMD or prevalent fractures had significantly lower values of SoS (P < 0.001) than the controls. ROC curve analysis applied to the study population confirmed that SoS was able to discriminate between the controls and osteoporotic subjects (area under the ROC curves were 0.82 (low bone mineral density) and 0.85 (prevalent fractures), respectively). Hip BMD was found to be the most significant variable when comparing the controls and the low density patients by stepwise discrimination and SoS significantly improved the discrimination between the groups when added to the hip BMD. The hip BMD was again the most discriminant variable when applying the same techniques to controls and patients with prevalent fractures, followed by SoS and lumbar BMD. A cut-off value of 1881 m/s is defined for SoS by logistic discrimination and likelihood ratio function. With this value, the sensitivity and the specificity for SoS used in the diagnosis of established osteoporosis were, 81.5% and 79.3%, respectively. Sensitivity and specificity were significantly improved when combining ultrasonometry and densitometry. CONCLUSION: Measurement of ultrasound velocity at the phalanges appears to be a precise and reproducible technique. SoS discriminates between normal post-menopausal women and patients with either low lumbar BMD or prevalent fractures to the same extent as BMD measurements.

Absorptiometry, Photon↗
PubMed1998

Crystal structure of aspartate decarboxylase at 2.2 A resolution provides evidence for an ester in protein self-processing.

The structure of L-aspartate-alpha-decarboxylase from E. coli has been determined at 2.2 A resolution. The enzyme is a tetramer with pseudofour-fold rotational symmetry. The subunits are six-stranded beta-barrels capped by small alpha-helices at each end. The active sites are located between adjacent subunits. The electron density provides evidence for catalytic pyruvoyl groups at three active sites and an ester at the fourth. The ester is an intermediate in the autocatalytic self-processing leading to formation of the pyruvoyl group. This unprecedented structure provides novel insights into the general phenomenon of protein processing.

Amino Acid Sequence↗
PubMed1998

Adverse events after polysaccharide meningococcal A&C vaccine.

The incidence of adverse events due to meningococcal polysaccharide A&C vaccine was studied in 312 subjects 18 months to 20 y of age who were part of a mass vaccination program. Fever > 38 degrees C occurred in 5.1% (95% CI: 3.1-8.4%). Injection site pain was reported in 78.8% (95% CI: 74.3-83.4%), was severe in 7.4% (95% CI: 4.7-10.9%) and was most frequent in the oldest age group.

Adolescent↗
PubMed1998

Visual evoked potentials during long periods of pattern-reversal stimulation in migraine.

We have previously shown that during repetitive pattern-reversal stimulation, lasting 2 min, the amplitude of the visual evoked potential (PR-VEP) increases in migraineurs when tested interictally whereas it decreases in healthy control subjects. According to Sappey-Marinier et al. (J Cereb Blood Flow Metab 1992; 12: 584-92) habituation of the PR-VEP in normal subjects is maxima after 12 min, at a time when there is a decrease of stimulation-enhanced lactate levels in the occipital cortex. We have therefore compared PR-VEP during long periods of repetitive stimulation in healthy control subjects (n = 25) and in patients suffering from migraine without (n = 25) and with aura (n = 15) between attacks. During uninterrupted stimulation at 3.1 Hz VEPs were sequentially averaged in blocks of 100 responses for a total duration of 15 min and analysed in terms of latencies and peak-to-peak amplitudes of N1-P1 and P1-N2 peaks. Amplitude changes from the baseline were calculated for each block, by comparison with the first block, and analysed statistically using Zerbe's method. The N1-P1 and P1-N2 amplitudes in the first block tended to be lower in migraineurs than in healthy control subjects. During the 15 min of stimulation, amplitudes of both components progressively decreased in control subjects, but remained stable in both groups of patients. The difference between patients and control subjects proved to be significant (P < 0.05). The neurophysiological data were not correlated with clinical features such as attack frequency or duration of illness. These results are yet another demonstration in migraine of an interictal habituation deficit in cortical information processing, which might favour lactate accumulation in sensory cortices during sustained activation.

Adult↗
PubMed1998

Bronchial responsiveness in active steelworkers.

Coke-oven workers are exposed to dust and irritant gases. Therefore they are at risk of developing lung diseases including chronic bronchitis. Nonspecific bronchial hyperresponsiveness (BHR) has been advocated as a potential risk factor predisposing to the development of chronic bronchitis. In a previous study, we showed that prevalence of BHR was higher in retired coke-oven workers than in retired blast furnace workers. The present study was carried out to determine the prevalence of BHR in active steelworkers. Thus, 137 coke-oven workers and 150 blast furnace workers underwent clinical examination, a standardized questionnaire for the study of respiratory symptoms, pulmonary function testing and methacholine aerosol challenge. The study demonstrates a higher prevalence and degree of BHR [provocative concentration of methacholine causing a 20% fall in forced expiratory volume in one second (PC20) < or = 8 mg x mL(-1)] in coke-oven workers than in blast furnace workers (31.4 versus 6.7%; p<0.001). Moreover, the frequency of respiratory symptoms and basal bronchial obstruction were greater among coke-oven workers with BHR in nonresponders. The basal maximum expiratory flow from 25-75% of forced vital capacity and the respiratory symptoms were correlated with bronchial responsiveness. The lack of correlation observed between BHR and the intensity of smoking or years spent in coke-oven environment may be explained by the high proportion of smokers, the worker turnover in the steel plant, and the "healthy worker effect". In conclusion, the higher prevalence and degree of bronchial hyperresponsiveness in coke-oven workers suggests that coke-oven pollutants are more intense irritants than those that escape from blast furnaces.

Adult↗
PubMed1998

Evaluation of a diphenylphosphorylazide-crosslinked collagen membrane for guided bone regeneration in mandibular defects in rats.

In the present study, the potential of a diphenylphosphorylazide-crosslinked type I bovine collagen membrane was evaluated in the healing of mandibular bone defects applying the biological concept of guided bone regeneration. The experiment was carried out on 25 Wistar rats. After exposing the mandibular ramus bilaterally, 5 mm diameter full-thickness circular bone defects were surgically created. While the defect on one side was covered by the membrane (experimental), the defect on the other side was left uncovered (control) before closure of the overlying soft tissues. The rats were sacrificed in groups of 5 after 7, 15, 30, 90, and 180 days of healing. Although at early stages of healing similar amounts of bone formation were observed in the experimental and control defects, after 1 month of healing, most of the experimental defects were completely closed with new bone, while in the control defects, only limited amounts of new bone were observed at the rims and in the lingual aspect of the lesions. In the 90- and 180-day animals, all experimental defects were completely closed, while in the control defects, no statistically significant increase in bone regeneration was observed. The increase in percentage of bone regeneration in the experimental defects was statistically significant between the 15-day specimens as compared with the 7-day specimens (P < 0.01) and likewise between 30-day and 15-day specimens (P < 0.001). It can be concluded that a DPPA-crosslinked collagen membrane yields biocompatibility, ad hoc mechanical hindrance, and handling characteristics suitable for guided bone regeneration applications in this experimental model.

Alveolar Bone Loss↗
PubMed1998

[Clinical manifestations of Stenotrophomas (Xanthomonas) maltophilia infection].

OBJECTIVE: Stenotrophomonas maltophilia (SM) is a gram-negative bacillus whose incidence like nosocomial pathogen has been incremented in the last years, especially in immunocompromised patients, subjected to invasive procedures and those receiving broad-spectrum antimicrobial therapy. METHOD: We report 15 isolations of SM between 1994-1996. RESULTS: The criteria for SM infection were fulfilled by 9 patients (60%), and 6 patients (40%) were colonized. The mean age of the patient was 60 +/- 12 years. Major predisposing factors in infections included venous catheterization (100%), prior surgery (86%), residence in ICU (80%), prior antibiotic therapy (80%) and intubation (66%). The most common underlying disease were heart disease (60%), treatment with immunosuppressors and/or steroids (46%) and chronic lung disease (46%). Ten cases (66%) had polymicrobial culture. The mortality rate was 40%. Risk factors associated with fatal outcome included the following: chronic lung disease (p = 0.043), nasogastric catheterization (p = 0.01), urinary tract catheterization (p = 0.02), intubation (p = 0.04) and the presence of pneumonia or sepsis by SM (p = 0.02). The most active agents were colistina (100%), cotrimoxazol (71%) and ceftazidima (53%). The isolates were highly resistant to first and second-generation cephalosporins (100%) tetracyclines (86%), aztreonam (91%) and imipenem (71%). CONCLUSION: SM cause a wide range of clinical syndromes and is more likely to cause infection or colonization in patients who have underlying disease. Due to its inherent multiple-antimicrobial resistance, it would appear its potential as a nosocomial pathogen will continue to increase. Therapy of patients should include cotrimoxazole.

Cross Infection↗
PubMed1998

Pancytopenia secondary to hemophagocytic syndrome in rheumatoid arthritis treated with methotrexate and sulfasalazine.

Hemophagocytic syndrome is an exceptional cause of pancytopenia. Its etiologies are most commonly viral or bacterial infections, lymphoproliferative syndromes, acquired or congenital immunodeficiencies, systemic diseases, or immunomodulatory treatment. We describe a patient with rheumatoid arthritis (RA) treated with methotrexate (MTX), sulfasalazine, and low dose corticosteroids, whose case was seriously complicated by the occurrence of acute febrile pancytopenia. The pancytopenia appeared secondary to hemophagocytic syndrome triggered by Escherichia coli septicemia. The evolution was marked by severe aggravation of RA, probably due to release of cytokines from macrophages (tumor necrosis factor-alpha, interleukin 6). Reintroduction of MTX (without sulfasalazine) resulted in partial remission and there was no reappearance of new hematological anomalies after 16 month followup. A knowledge of this syndrome is particularly important, since it mimics drug toxicity and other complications such as lymphoproliferative diseases.

Antirheumatic Agents↗