Biomedical subjects

A Albert

Publications and source records attributed to A Albert.

At least 19 recordsLinked to original sources

PubMed1996

Estimation of antibodies to Newcastle disease virus in tears.

Micro-haemagglutination inhibition tests (Micro-HI) were used to measure the level of maternal IgG in the tears of chicks and also to measure the levels of HI antibodies in the tears and serum after vaccination with "F" strain of Newcastle disease virus (NDV) and in the face of an outbreak of Newcastle disease. There was a 1.4 fold difference between the maternal IgG concentration in the serum and tears. The ratio of serum IgG to lachrymal IgG after maternal transfer was 4 to 5:1 on day 4 to 9 and decreased to 2.6:1 on day 12 post-hatch. The intra-ocular vaccination of chicks with "F" strain of NDV resulted in the highest titre of HI antibodies in the tears though there was no significant difference in the response of chicks vaccinated through intranasal, oral and intravenous routes. In the face of an ND outbreak, the level of HI antibodies in the tears during the acute phase was very high and persisted at the same level for 14 days.

Animals↗

PubMed1996

Intrauterine contraception in nulligravid vs parous women.

The performance of MLCu-250 IUDs inserted in 525 nulligravid women was studied for four years and is compared to the results obtained in the same period from 2770 parous women using TCu-200, 7Cu-200 and Nova-T IUDs. In every case the choice of the particular IUD model took into account hysterometry and diameter of the inner cervical orifice in order to aim at the highest theoretical efficacy. The MLCu-250 in nulligravid women produced failure and expulsion rates below those of the other models in parous users; no difference was observed in the case of removal because of bleeding or pain. Finally, there was no case of subsequent infertility or pelvic inflammatory disease (PID) recorded among nulliparae. These results suggest that an adequate choice of the IUD model for nulliparous women with low risk of PID gives as reliable results as in multiparous women.

Adolescent↗

PubMed1996

New methods of mathematical analysis for studies of intrauterine contraception.

The authors present two new procedures of mathematical analysis to evaluate the incidents which arise during the use of any contraceptive method. These two new approaches, which the authors call the Probability Index (PI) and the Weighted Average Index (WAI), are compared to those by Pearl and Tietze. Their conclusions are that the PI, although the best estimator of real probability, is not as functional as the WAI. The latter is not only much easier to calculate than PI, but also presents a greater correlation, prediction accuracy and discriminant power than the Pearl and Tietze indexes.

Contraception↗

PubMed1996

A systematic view on medical informatics.

Medical informatics is defined as the scientific discipline concerned with the systematic processing of data, information and knowledge in medicine and health care. The domain of medical informatics (including health informatics), its aim, methods and tools, and its relevance to other disciplines in medicine and health sciences are outlined. It is recognized that one of the major tasks of medical informatics is modelling processes. In this context, biological, communication, decision, engineering, educational, organizational and computational processes are distinguished and described.

Computer Communication Networks↗

PubMed1996

Myocellular enzyme leakage, polymorphonuclear neutrophil activation and delayed onset muscle soreness induced by isokinetic eccentric exercise.

To address the question of whether delayed onset muscular soreness (DOMS) following intense eccentric muscle contraction could be due to increased production of the arachidonic acid derived product prostaglandin E2 (PGE2). 10 healthy male subjects were submitted to eccentric and concentric isokinetic exercises on a Kin Trex device at 60 degrees/s angular velocity. Exercise consisted of 8 stages of 5 maximal contractions of the knee extensor and flexor muscle groups of both legs separated by 1 min rest phases. There was an interval of at least 30 days between eccentric and concentric testing, and the order of the two exercise sessions was randomly assigned. The subjective presence and intensity of DOMS was evaluated using a visual analogue scale, immediately, following 24 h and 48 h after each test. Five blood samples were drawn from an antecubital vein: at rest before exercise, immediately after, after 30 min recovery, 24 h and 48 h after the tests. The magnitude of the acute inflammatory response to exercise was assessed by measuring plasma levels of polymorphonuclear elastase ([EL]), myeloperoxidase ([MPO]) and PGE2 ([PGE2]). Using two way analysis of variance, it appeared that only eccentric exercise significantly increased [EL] and DOMS, especially of the hamstring muscles. Furthermore, a significant decrease in eccentric peak torque of this muscle group only was observed on day 2 after eccentric work (- 21%; P < 0.002). Serum activity of creatine kinase and serum concentration of myoglobin increased significantly 24 and 48 h after both exercise tests. However, these variables reached significantly higher values following eccentric contractions 48 h after exercise. Mean [PGE2] in the two exercise modes remained unchanged over time and were practically equal at each time point. On the basis of these findings, we conclude that the magnitude of polymorphonuclear (PMN) activation, muscle damage, and DOMS are greater after eccentric than after concentric muscle contractions. However, the hypothesized interplay between muscle damage, increased PGE2 production, DOMS sensations, and reduced isokinetic muscle performance was not substantiated by the present results.

Adult↗

PubMed1996

Protein engineering loops in aspartic proteinases: site-directed mutagenesis, biochemical characterization and X-ray analysis of chymosin with a replaced loop from rhizopuspepsin.

The loop exchange mutant chymosin 155-164 rhizopuspepsin was expressed in Trichoderma reesei and exported into the medium to yield a correctly folded and active product. The biochemical characterization and crystal structure determination at 2.5 A resolution confirm that the mutant enzyme adopts a native fold. However, the conformation of the mutated loop is unlike that in native rhizopuspepsin and involves the chelation of a water molecule in the loop. Kinetic analysis using two synthetic peptide substrates (six and 15 residues long) and the natural substrate, milk, revealed a reduction in the activity of the mutant enzyme with respect to the native when acting on both the long peptide substrate and milk. This may be a consequence of the different charge distribution of the mutated loop, its increased size and/or its different conformation.

Amino Acid Sequence↗

PubMed1996

Effect of propofol on in vitro lipid peroxidation induced by different free radical generating systems: a comparison with vitamin E.

Propofol has been reported to have antioxidant properties and to inhibit lipid peroxidation. In this study, we examined the ability of propofol to inhibit lipid peroxidation induced by three free radical systems (hydroxyl, ferryl, and oxo-ferryl radicals), and we compared the effect of propofol with that of vitamin E, an endogenous antioxidant. Lipid peroxidation was induced by exposing a linoleic acid emulsion to either water gamma radiation, a ferrous iron-ascorbate solution, or human hemoglobin, generating the hydroxyl, ferryl, and oxo-ferryl radicals, respectively. Each experiment was performed in triplicate with and without propofol or vitamin E at concentrations between 10(-5) and 10(-4) M. Lipid peroxidation was quantified by gas chromatography measurement of the pentane released (nmoles) from lipid decomposition. In each condition, a significant dose-response relationship was found between the release of pentane and the concentration of either propofol or vitamin E. The antioxidant activities of both agents were similar but significantly higher against the hydroxyl than the ferryl and oxo-ferryl radicals. The study suggests that propofol could be beneficial as an anesthetic or sedative drug in patients presenting pathologies associated with free radical reactions.

Anesthetics, Intravenous↗

PubMed1996

Staging of the mediastinum: value of positron emission tomography imaging in non-small cell lung cancer.

Recent studies have shown limitations of morphological imaging in staging mediastinal lymph node involvement in lung cancer. In contrast to computed tomography (CT), which depends primarily on anatomical imaging features, positron emission tomography (PET) with 18-fluorodeoxyglucose (FDG) depends mainly on the metabolic characteristics of a tissue for the diagnosis of disease. We have performed a prospective study comparing FDG-PET and CT of the thorax in the presurgical assessment of the mediastinum in 50 patients with newly diagnosed non-small cell lung cancer (NSCLC). CT and PET scans were interpreted separately, and results were compared to pathological staging obtained during thoracotomy. Hilar or mediastinal lymph node involvement was present in 58%. In staging for lymph node involvement, CT had a sensitivity of 72% and specificity of 81%, whereas PET had a sensitivity and specificity of 90% and 86%, respectively. When the PET study was compared to histological results, there were four cases showing more advanced mediastinal involvement with PET and four cases showing less involvement with PET. From our preliminary results, we conclude that positron emission tomography with 18-fluorodeoxyglucose is significantly more accurate than computed tomography in the mediastinal staging of non-small cell lung cancer.

Aged↗

PubMed1996

Plasma concentration of estradiol following transdermal administration of Systen 50 or Menorest 50.

Circulating levels of 17 beta estradiol (E2) following the administration of fixed doses of E2, show a great variability in kinetics depending upon the product administrated, the routes of administration, and the interindividual variations in absorption and metabolism. This might have important implications both in terms of tolerance and effectiveness. Two new forms of transdermal E2 (SYSTEN Cilag and MENOREST Rhone-Poulenc Rorer) have been recently accepted in Europe for the treatment of climacteric symptoms. The present study was undertaken to compare the pharmacokinetic characteristics of plasma E2 profile under these two drugs. It was carried out in 30 healthy postmenopausal volunteers according to good clinical practice after informed consent, as a single blind, randomised, cross-over study during the classical wearing period of 4 days. Plasma E2 concentration was determined 24 hours before, 1/2 hour before and then 2, 4, 8, 12, 24, 48, 72, 84, 96 hours after the first patch administration. E2 measurement was performed using a specific direct radioimmunoassay developed in the FRH laboratories. The main criteria for this method were an intraassay coefficient of variation (CV) less than 6%, an interassay CV less than 8% in a concentration range of 15-140 pg/ml and a quantitative detection limit (LOQ) of 2.7 pg/ml with a 20% CV. The following kinetic parameters were analysed: C(max), C(mean), C96 and MRT. The bioequivalence was assessed by analysis of variance of C(max), C(mean), C96 and AuC after logarithmic transformation, complemented by Westlake test (95%). Data show that these two products are identical in terms of C(max) but C(mean), C96 and AuC are statistically greater when MENOREST 50(R) is administered; furthermore, E2 levels decrease more rapidly and more deeply with SYSTEN 50 than MENOREST 50. The differences of pharmacokinetic profiles after administration of two different forms of the same dose of 50 micrograms transdermal 17 beta estradiol might have important medical consequences.

Administration, Cutaneous↗

PubMed1996

Kinking of the internal carotid artery: clinical significance and surgical management.

The authors report on 62 surgical corrections for kinking of the internal carotid artery during a 13-year period (1980-1993). This represents 2.8% of all carotid operative procedures (n = 2188) in the same period. It always concerned a significant (< 60 degrees) angulation of a redundant internal carotid artery, that in all but 3 cases was associated with atherosclerotic involvement of the carotid bifurcation. The indication to surgery included transient hemispheric or ocular ischaemia in 25.5% of cases, a regressive neurologic deficit in 8%, a minor stroke in 3%, a stroke in evolution in 11%, and non-lateralized cerebral ischaemia in 21%. In 19 patients (31%) it concerned an asymptomatic high degree stenosis. The surgical technique consisted in carotid transposition-reimplantation after eversion endarterectomy in 37 cases, in posterior transverse plication with patch angioplasty in 20 cases, and in segmental excision with venous interposition graft in 5 cases. There was one postoperative death. The morbidity include one ipsilateral non-fatal stroke and 3 transient ischaemic attacks. A complete long-term follow-up (mean duration 3.4 years) is available for 57 patients. The late incidence of stroke is 1.5% per year. The 5-year survival attains 67%. These long-term results are comparable to the outcome of standard endarterectomy in the same institution. The authors discuss the indication, techniques, and outcome of surgical correction of kinked internal carotid artery. They recommend a shortening procedure, often associated with endarterectomy for severely kinked vessels (angulation 60 degrees or less), symptomatic or not.

Aged↗

PubMed1996

[[Wallonian general physicians. Which prescriptions should be given to elderly persons over 75 years?].

Explore the source record for details and available documents.

Aged↗

PubMed1995

Bone mineral density of the spine and the hip measured with dual energy X-ray absorptiometry: normal range and fracture threshold for western European (Belgian) postmenopausal females.

Bone mineral density (BMD) of the spine and the different regions of interest (ROI) of the hip were measured by dual energy X-ray absorptiometry in 278 healthy Belgian postmenopausal women and 93 postmenopausal type I osteoporotic females in order to: a) determine the normal range for lumbar and hip BMD values; b) define an "hypothetical" fracture threshold in this population; c) determine the preferential region to be considered for clinical use in type I osteoporosis. In the normal subjects, there is a negative relationship (< 0.001) between age or time elapsed since menopause (Tm) and BMD measured at the level of the spine or at the ROI of the hip. For the spine, evidence of a curvilinear relationship was assessed. Regressions of BMD at the hip as a function of age or time elapsed since menopause, were best fitted by a linear relationship. In the population of postmenopausal women who have experienced a vertebral crush fracture, no relationships were observed between spine BMD and age or Tm but the osteoporotic women had a spine BMD significantly lower compared to age-matched normal controls: Z-score = -1.2 +/- 0.6 (mean +/- SD) (p < 0.0001). Fracture threshold calculated as the 90th percentile of spine BMD measured in osteoporotic patients was 0.840 g/cm2, corresponding to the mean value -1 SD for a population of women aged 51 years.

Absorptiometry, Photon↗

PubMed1995

Long-term performance in vitro and in vivo of dual-energy X-ray absorptiometry.

Dual-energy X-ray absorptiometry (DXA) is actually considered as one of the most appropriate techniques for measuring bone mineral content (BMC) and bone mineral density (BMD). An anthropomorphic phantom and a 25-year-old girl were repeatedly measured, 160 times and 50 times respectively, over an 18-month period to investigate performance in vitro and in vivo of a commercial DXA equipment (HOLOGIC QDR 1000). DXA is a highly accurate technique, the BMC and BMD determinations only overestimated the exact value of the phantom by 0.20% and 0.51% respectively. In vivo long-term (18 months) reproducibility of BMD of the spine is characterized by an interassay coefficient of variation (CVt) of 0.8% while, for the different regions of interest of the hip, BMD CVt varies from 1.1% (total zone) to 5.3% (Ward's triangle). In the subject tested, BMD sensitivity for changes of 2.2% at the lumbar spine and 3% at the hip were recorded.

Absorptiometry, Photon↗

PubMed1995

The impact of renal revascularisation on renal dysfunction.

AIM: To determine the value of kidney revascularisation in patients with impaired renal function and correctable renal artery stenosis, the authors reviewed their surgical experience from 1978 to 1990. PATIENTS AND METHODS: The study population included 23 patients with ischaemic nephropathy whose preoperative baseline creatinine level exceeded 20 mg/l (range 21-65 mg/l). This represents 20% of all patients operated on for renal artery disease during the same time interval. Preoperative risk profile, operative mortality, impact on hypertension and on renal function, and late survival were analysed. Renal function response to kidney revascularisation was defined as favourable (20% or more reduction of serum creatinine), moderate (stabilised serum creatinine values) or bad (further deterioration of renal function). All patients had atherosclerotic renal artery disease, involving a solitary kidney in five, both kidneys in 15 and one of the two kidneys in three patients. Hypertension was present in 74%. Revascularisation was unilateral in 10, bilateral in nine and associated with controlateral nephrectomy in four patients. RESULTS: Four patients died postoperatively (three myocardial infarctions, one stroke). Four patients needed postoperative short-term dialysis. After operation, renal function improved in 13, stabilised in six and deteriorated in four patients (of whom two died). Follow-up among the survivors averaged 46 months. The mean serum creatinine value at last follow-up visit was 26.2 mg/l, a decrease of 7.7 mg/l compared to preoperative values (p < 0.05). Overall, 69% of azotemic patients submitted to renal revascularisation manifested a favourable response (45% improved and 24% stabilised). Three patients required long-term dialysis. The 5-year survival rate was 48%. CONCLUSION: These data suggest that kidney revascularisation in patients with ischaemic nephropathy can restore or stabilise renal function, preventing evolution and end-stage renal disease and dialysis dependency.

Chronic Disease↗

PubMed1995

Thrombin does not alter vascular hyporeactivity in models of endotoxin-induced septic shock in rats.

1. Hypotension and vascular hyporesponsiveness to vasoconstrictors are observed during endotoxic shock, and are associated with increased production of nitric oxide in the vascular wall. Disseminated intravascular coagulation is another feature of septicaemia. We hypothesized that thrombin generated during disseminated intravascular coagulation might modulate the changes in vascular tone induced by endotoxin. 2. Incubation of rat aortic rings for 4 h with alpha-thrombin (0.003-3.0 NIH units/ml) did not change their reactivity to noradrenaline. Incubation for 4 h with lipopolysaccharide increased the EC50 for noradrenaline, whereas co-incubation of thrombin (0.5 NIH units/ml) with lipopolysaccharide did not alter this hyporeactivity to noradrenaline. 3. In vivo in rats, lipopolysaccharide caused early (1 h) and late (4-6 h) hyporeactivity to noradrenaline. In rats infused with lipopolysaccharide and heparin (1 U min-1 kg-1, 0.4 ml/h) or hirudin (2.2 mg ml-1 kg-1, 0.8 ml/h), vasopressor responses to noradrenaline were not different from those after infusion of lipopolysaccharide alone. Aortic rings taken from rats receiving both anticoagulant treatment and lipopolysaccharide had the same sensitivity to noradrenaline as those obtained from rats receiving lipopolysaccharide alone. 4. Our results suggest that, in vivo, disseminated intravascular coagulation does not modify the early and late effects of lipopolysaccharide on arterial pressure and that, in vitro, thrombin neither induces hyporeactivity to noradrenaline nor modifies lipopolysaccharide-induced hyporeactivity. We propose that thrombin generated during disseminated intravascular coagulation in rats does not play a major role in the alterations of vascular tone observed during endotoxic shock.

Animals↗

PubMed1995

Factors regulating megakaryocyte progenitor commitment to polyploidization.

Recognizable megakaryocytes are polyploid cells generated by a clonogenic, diploid progenitor, termed CFU-MKC (colony forming unit, megakaryocyte). In order to quantify polyploidization, ploidy histograms of megakaryocytes determined by microphotometric or flow cytometric measurements of megakaryocyte DNA have generally been used. However these techniques provide no information on the rate of commitment of CFU-MKC to polyploidy. Using a technique of clonal analysis determining the distributions of the number of doublings (NbD) undergone by CFU-MKC before committing to polyploidization, the polyploidization probability of CFU-MKC could be derived. This probability was found to be a constant independent from CFU-MKC mitotic history, since NbD distributions are exponential functions characterized by a constant rate of decay per doubling. By studying the effects of growth factors on polyploidization probability, it was also shown that: (1) this parameter is negatively regulated by growth factors contained in poke-weed or WEHI conditioned media, as well as by erythropoietin; (2) commitment to polyploidization does not require prior CFU-MKC division; (3) bipotent erythroid-megakaryocyte progenitors have a lower polyploidization probability than CFU-MKC; (4) determination of polyploidization probability reflects the activity of growth factors with greater accuracy than megakaryocyte colony count.

Acetylcholinesterase↗

PubMed1995

Factors regulating megakaryocyte progenitor commitment to polyploidization.

Acetylcholinesterase↗

PubMed1994

Drug utilization review of oral forms of benzodiazepines in a Belgian 635-bed teaching hospital.

A retrospective study based on 4,307 drug patient records was designed to establish a chart of the consumption of benzodiazepines administered orally in a 635-bed teaching hospital, and to determine the influence of patient-related parameters (age, sex) and hospital-related parameters (type of services, prescription habits, etc.) on benzodiazepine utilization. Another objective was to evaluate to which extent benzodiazepine consumption can be induced by hospitalization. A minor but statistically significant difference (p < 0.05) was observed between the proportion of male (42.7%) and female (46.5%) users. Besides, when evaluating the consumption in number of defined daily doses per 100 beddays, there was little difference between the consumption of male (51.2 defined daily doses per 100 beddays) and female (52.8 defined daily doses per 100 beddays) patients. A significant influence of age was also observed with an increase of benzodiazepine use for patients aged from 15-20 to 40-45, followed by a progressive decrease for higher ages. With hypnotics, no peak of consumption related to age was observed but an increase of consumption from age 15-20 to 30-35. For higher ages the consumption of hypnotics was nearly stable or rising slowly. High variations in benzodiazepine utilization were recorded between hospital wards (median: 50.77 defined daily doses per 100 beddays, range 0.23-263.9). Finally, it was found that 6.8% of patients with a benzodiazepine treatment initiated during hospitalization may be considered as potential benzodiazepine consumers after discharge.

Administration, Oral↗