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Biomedical subjects

A Albert

Publications and source records attributed to A Albert.

At least 145 records · Page 8Linked to original sources
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.

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↗
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↗
PubMed1994

The 6-kilobase c-erbB2 promoter contains positive and negative regulatory elements functional in human mammary cell lines.

A 6-kilobase fragment extending at the 5'-end of the c-erbB2 protooncogene was isolated from a normal human lymphocyte genomic DNA library. The full-length fragment and five subfragments with identical 3'-ends were obtained by progressive unidirectional deletion from the 5'-end and were cloned in front of the luciferase reporter gene. The hybrid genes were analyzed for transcriptional activity in human mammary cell lines synthesizing low (HBL-100 and T-47D), moderate (MDA-MB-453), or high (BT-474) amounts of the c-erbB2 mRNA and were also analyzed in HeLa cells. Gene-specific expression was observed, indicating the presence of multiple cis-acting sequences in the c-erbB2 promoter. A major negative element is located in the -2- to -4-kilobase region. It is flanked on both sides by positive elements that display enhanced transcriptional activity in the BT-474 tumor cells only. While predominant in the low-expressing cells, the effect of the repressor appears to be overcome by the distal transactivator in the high-expressing BT-474 cells, resulting in a 15 to 50 times increase in luciferase activity relative to the HBL-100 and T-47D cells, respectively. Cell-specific expression relies on the trans-acting factors present in the different cell lines. The formation of cell-specific protein-DNA complexes was demonstrated by gel retardation assay.

Biomarkers, Tumor↗
PubMed1994

Clonal structural chromosome aberrations in fibrous dysplasia.

Cytogenetic analysis of short-term cultures from a case of monostotic fibrous dysplasia in a 14-year-old girl revealed multiple clonal structural rearrangements with evidence of clonal evolution. The karyotype was 46,XX,del(3)(q27),add(10)(q22),add(12)(p13)/46,idem,t(3;8)(p21;q13 ),add(10) (q26),der(15)del(15)del(15)(q15q22)ins(15;?) q15;?)/46,id em,-X,+2,t(3;8),add(10),der(15). The finding of clonal structural aberrations suggests that fibrous dysplasia is a neoplastic lesion which develops as the result of somatic mutations.

Adolescent↗
PubMed1994

Propofol protects cultured rat hippocampal neurons against N-methyl-D-aspartate receptor-mediated glutamate toxicity.

The effect of propofol on the toxicity induced by glutamate (GLU), N-methyl-D-aspartate (NMDA), kainate (KA), and amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) was investigated on cultured fetal rat hippocampal neurons. The degree of neuronal injury was quantified by measuring the release of the neuron-specific enolase (NSE) into the culture media. The toxicity induced by brief exposure to GLU (10(-4) M) or to NMDA (10(-4) M) was significantly reduced by propofol, whereas that elicited by KA, AMPA (10(-4) M), or long GLU exposure was unaffected. In conclusion, high concentrations of propofol significantly attenuate NMDA receptor-mediated glutamate neurotoxicity in vitro. Further studies are needed to confirm this beneficial effect in vivo and to evaluate propofol as a neuroprotective anesthetic agent in pathologies involving glutamate release and NMDA-mediated toxicity.

Animals↗
PubMed1994

A 5-year controlled randomized study of prevention of postmenopausal trabecular bone loss with nasal salmon calcitonin and calcium.

The aim of this paper was to evaluate the long-term (5 years) efficacy of nasal salmon calcitonin in prevention of trabecular postmenopausal bone loss, which was a follow-up of a previously published study (3 years); a randomized, controlled group comparison. One hundred healthy postmenopausal women were randomly chosen from those (186) having completed the 3 year protocol. The 100 women were allocated to an additional 2 year period (total of 5 years) of treatment with either 500 mg d-1, 5 days week-1 of calcium or the same amount of calcium plus 50 IU d-1, 5 days per week of nasal salmon calcitonin, 87 (87%) women complied with the protocol throughout. The main outcome measures were the bone mineral density of the lumbar spine (1-BMD) (DPA) and biochemical parameters reflecting bone turnover (serum alkaline phosphatases, urinary calcium/creatinine and hydroxyproline/creatinine ratios). The women receiving calcium alone presented a significant decrease in 1-BMD after 6 months [-1.6 (0.5)%] [mean(SEM)] (P < 0.01) and this decrease remained significant after 36 months [-6.1(0.8)%] (P < 0.01) and until the end of the trial [-6.6(1.0)% at t60] (P < 0.01). In women receiving calcium and calcitonin, 1-BMD significantly increased after 36 months [+2(0.7%] (P < 0.01) and 42 months [+2.5(0.7)%] (P < 0.01 and was unchanged at the other times of investigation [+1.1 (1.1)% at t60] (NS). The evolution of BMD in the two groups was highly significantly different (P < 0.001) since the sixth month of the study and remained so until the end of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1994

Factors influencing between-laboratory variability of C-reactive protein results as evidenced by the Belgian External Quality Assessment(EQA) Scheme.

Based on results from the Belgian External Quality Assessment (EQA) Scheme, we studied the main factors affecting the between-laboratory variation of C-reactive protein determination. Participants using homogeneous systems with several calibration points generally achieved better performance. Working temperatures influenced the results to a lesser extent. The present study stresses the importance for EQA organizers to collect more detailed information about CRP analytical methods used by the participants. It also suggests that manufacturers should be more involved in the management of quality, in particular by striving for standardization of the material (kit and calibrator) they produce for CRP assay.

Belgium↗
PubMed1994

[Experimental alkaline reflux esophagitis. Role of the refluxed material].

Alkaline reflux is new recognised to play an important place in gastroesophageal reflux disease. In order to investigate the role of refluxate in the development of esophagitis we have performed an experimental study in laboratory animals submitted to alkaline reflux inducing operations. We produced esophagitis in two experimental groups of Sprague-Dawley rats: group I, end-to-side esophagojejunostomy (EY) and group II, esophagojejunostomy with partial derivation of afferent loop by an omega-like conduit (EO) designed to attain lesser reflux. Group III consisted of sham laparotomized animals (L). RESULTS. At day 14, all the animals of experimental groups have developed esophagitis, but the macroscopic extent and histological grade in group EO (med: 27 mm; grade 2) were significantly lower than in group EY (med: 35 mm; grade 3). Biochemical measurements (med) in esophageal washout revealed: a) pH were alkaline in all groups with a decrease in experimental groups that was only significant in group EY; b) Amylase, lipase and bile acids in groups EY (8090; 498; 32) and EO (12840; 449; 50) were similar, but significantly more higher than in group L (920; 24; 0). The analysis of correlation between esophagitis parameters and biochemical measurements revealed no significant ones except for pH (r = -.437 and -.417). CONCLUSIONS. 1- The alternative model (EO) presents lesser grade and extent of esophagitis. 2) The refluxate was rich in bile acids and pancreatic enzymes what is proof of the actual occurrence of reflux and supports its determinant contribute to the development of esophagitis. 3) Esophagitis has developed at alkaline pH but with no alkalinity increase in the experimental groups what indicate that "alkaline reflux esophagitis" is not an appropriate denomination. 4) The discrepancy between the biochemical analysis in esophageal washout and the extent and grade of esophagitis suggests that others than the nature and amount of refluxate (e.g. mucosal resistance) could play a role in reflux esophagitis.

Amylases↗
PubMed1993

[Macrophage activation syndrome in lupus].

A patient with systemic lupus erythematosus developed unexplained fever, nonregenerative anemia, leukopenia, and elevations in serum triglyceride and ferritin levels. Bone marrow studies established the diagnosis of macrophage activation syndrome with active hemophagocytosis. No infectious cause was found but pulmonary nocardiosis developed during the course of the disease. Intravenous gammaglobulin therapy was followed by a transient remission. Cyclophosphamide was given subsequently. In lupus patients, macrophage activation syndrome is exceedingly rare and has the same clinical, laboratory, and histologic features as those seen in patients with hemopathies, infections, or immune deficiencies. Investigations for an underlying infection are often negative, suggesting that the macrophage activation syndrome is due to lupus-related immune changes. Treatment is not standardized and relapses are common. This diagnosis should be considered in lupus patients with febrile pancytopenia.

Adult↗
PubMed1993

Sexual arousal in diabetic females: physiological and self-report measures.

Diabetes mellitus, a major health problem afflicting 500,000 Americans each year, is a leading cause of male erectile difficulties. Diabetic women may be susceptible to a similar diabetic pathogenesis for sexual problems but information about the effect of diabetes on female sexual response is sparse and conflicting. Past research has been based upon self-report measures, a methodology flawed by susceptibility to response bias. Whether diabetic women differed from a matched nondiabetic control group in their physiological as well as subjective response to erotic stimulus exposures was investigated. Vaginal photoplethysmographic measures of capillary engorgement were taken while subjects individually viewed counterbalanced erotic and non-erotic videotape presentations. Graphically and statistically analyzed results indicated that diabetic women demonstrated significantly less physiological arousal to erotic stimuli than controls, whereas their subjective responses were comparable. These objective, physiological findings support and extend previous subjectively based research which found potential diabetes-related sexual dysfunction in female diabetics. The groups did not differ, however, in the reported occurrence of sexual difficulties.

Adolescent↗
PubMed1993

Gastroschisis in the partially extraamniotic fetus: experimental study.

The short, thick, matted bowel, often found in gastroschisis, has been attributed to a variety of factors. We designed an original animal model in order to isolate the effect of amniotic fluid on the fetal bowel. We created experimental gastroschisis in fetal rabbits. Extruded bowel was kept out of the amniotic sac in half of the operated fetuses. At term, 7 days after surgery, 21 surviving fetuses (12 intraamniotic gastroschisis [IAG] and 9 extraamniotic gastroschisis [EAG]) and 16 control littermates were collected for study. Five parameters were measured in each animal: body weight, intestinal weight, intestinal length, bowel diameter, and bowel wall thickness. Fetal mortality due to the extraamniotic fixation technique was 25%. We found no statistically significant difference in body weight, intestinal weight, or bowel wall thickness. An enormous difference was found in intestinal length (P < .0001 among the three groups). Bowel diameter was significantly different (P = .02) in the extreme groups (IAG and controls), with the intestine being more dilated in IAG than in EAG and controls. Gastroschisis in the absence of amniotic fluid was not as damaging to the fetal intestine as "natural" intraamniotic gastroschisis.

Abdominal Muscles↗
PubMed1993

Wound healing in the fetal period: the resistance of the scar to rupture.

Wound healing in the fetal period is fundamentally different from that of the adult. In order to better understand this difference, we have studied wound healing in three types of wounds which are the most common in surgical practice, and have paid special attention to tensile strength in the scar. A sutured wound, a nonsutured wound, and an electrocautery burn were performed on a group of 30 rabbit fetuses with a gestational age of 23 days. Seven days later, the resulting scars were examined using histological, mechanical, and biochemical studies. The results were compared with those obtained in a group of 30 newborn rabbits and in a group of 30 adult rabbits who had had the same type of wounds performed on them. The body weight of operated fetuses was smaller than their control siblings. The sutured wound in the fetuses showed a more perfect macroscopic repair than in older subjects. However, the nonsutured wounds and the burns of the fetal group did not close. In the fetuses, the tensile strength of the sutured wound was 20% of the tensile strength of healthy skin. A similar relationship occurred in the group of adult rabbits. In the sutured wound of the fetal group, the synthesis of collagen was significantly less than in the adult group. The ratio between hydroxyproline (HYP) concentration in the sutured wound and HYP concentration in healthy skin was also significantly less in the fetal group than in the adult group.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1993

[Therapeutic approach in a fetus with posterior urethral valves].

A pregnant woman was diagnosed with fetal uropathy at 18 weeks gestation. A thorough examination revealed bilateral hydronephrosis, megacystis with bladder neck and posterior urethral dilatation, normohydramnios, normal echocardiography and normal male karyotype. From the 20th week on she developed a progressive oligohydramnios, and the left kidney became hyperechogenic. Fetal urine analysis at week 21 showed hypotonic urine in both renal pelvises, and a beta 2 microglobulin of 8.5 mg/l. on the right side and 18 mg/l. on the left one, suggesting some degree of function on the right kidney. A vesico-amniotic shunt was placed at week 22, which was ineffective, and another shunt was placed two weeks later. Twenty-four hours later the bladder size decreased, but amniotic fluid did not increase and a great amount of ascitis developed, which was attributed to catheter migration. On week 25, the abdomen was decompressed through a peritoneal-amniotic shunt. Ascitis decreased thereafter, but oligohydramnios remained unchanged. The patient died 20 hours after a cesarean section was performed at the 31st week. The necropsy diagnoses were: posterior urethral valves, bilateral renal dysplasia and pulmonary hypoplasia. This case illustrates the difficulty in establishing a prognosis based on the prenatal data available at present.

Adult↗
PubMed1993

[Is age a limiting factor for carotid surgery?].

To evaluate the role of carotid surgery in elderly patients 75 years and older, we reviewed 912 carotid endarterectomies performed on 806 patients between 1987 and 1990. There were 151 patients (19% of the whole series) aged 75 years and older (160 endarterectomies, group A), including 29 octogenarians, vs 655 patients under 75 years of age (group B). There were more women in the elderly age group (44%) than in the younger one (38%). Symptoms, risk factors, operative outcome and follow up data of the two groups were compared. The risk profile was similar for the two age groups, with exception for coronary heart disease, less frequent in the older patient group (25% had previous infarction vs 44%). Indication for carotid endarterectomy was different in the two age groups: 41% of group A underwent prophylactic thrombendarterectomy for high degree stenosis, while only 30% of group B had asymptomatic carotid disease. In group A, 6% of the patients had carotid endarterectomy after recovering from a mild stroke, vs 2% in group B. Angiography revealed bilateral carotid disease in 59% of the group A patients (including 15% with contralateral occlusion) vs 40% in group B. Operative mortality was 1.5% for the younger age group vs 2.5% for the older age group. The cause of death was cardiac in 60%. A follow up is available for all patients who benefited carotid endarterectomy since 1976, including 180 patients aged 75 years or older.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗