Biomedical subjects

A Becker

Publications and source records attributed to A Becker.

At least 145 records · Page 8Linked to original sources

PubMed1999

Stoma care nurses: good value for money?

Decreasing financial resources in health services often lead to wholesale budget reducing in hospitals. Enterostomal therapists are more and more concerned by this situation. Data on the cost-effectiveness of stoma therapy have not existed, a gap filled by the present study. From January to December 1996 data from 94 patients about therapy-related costs, outcome, and evaluation of stoma therapy from the patient's point of view were ascertained prospectively. For an average (SD) of 14.6 (7.1) patient contacts for stoma planning, advice, care, and so on the average duration was 12.9 (9.1) minutes per contact. At an average exchange rate of 1.50 German marks (DM) per US dollar in 1996 the enterostomal therapist's part of the total staff costs was US$15,212 (2.7%), the cost of stoma products was US$7750 (4.5% of the total costs of medical supplies). About 89.3% of the patients classified the enterostomal therapist necessary and indispensable; 70.3% of the patients said they could cope with their stoma very well to well at the time of questioning. In contrast, 69.2% of those questioned declared that without the care by the enterostomal therapist in hospital they would be able to cope with their stoma only poorly to very poorly. We conclude that from the patient's point of view the costs of our stoma therapy are justifiably low. Therefore we see no reason for a discussion about rationalization measures regarding our stoma therapy staff.

Adult↗

PubMed1999

Involvement of delta-opioid receptors in pentylenetetrazol kindling development and kindling-related processes in rats.

The role of delta-opioid receptors on the development of kindling induced by the convulsant pentylenetetrazol (37.5 mg kg(-1) i.p.) was investigated in rats. Besides the seizure development, the kindling induced enhancement of glutamate binding and the kindling-induced learning deficit were examined. A clear depression of kindling development by blocking of delta-opioid receptors by intracerebroventricular administration of naltrindole (10 nmol/5 microl) was found. In an acute convulsion test performed 8 days after kindling completion, animals pretreated with naltrindole during kindling induction showed lower seizure stages compared to saline-pretreated kindled animals. The kindling-induced increase in hippocampal glutamate binding was completely prevented by naltrindole, whereas the kindling-induced learning deficit was not influenced. The learning performance of control animals pretreated with naltrindole was very low. It was hypothesized that the various consequences of kindling induction could be influenced separately. Summarizing the results, an involvement of the delta-opioid system in mechanisms underlying chemical kindling was clearly demonstrated. Interactions of endogenous opioid systems with glutamatergic transmission were suggested.

Animals↗

PubMed1999

Social behaviour in rats lesioned with ibotenic acid in the hippocampus: quantitative and qualitative analysis.

RATIONALE: Neonatal ibotenic acid lesion of the ventral hippocampus was proposed as a relevant animal model of schizophrenia reflecting positive as well as negative symptoms of this disease. Before and after reaching maturity, specific alterations in the animals' social behaviour were found. OBJECTIVE: In this study, social behaviour of ventral hippocampal lesioned rats was analysed. For comparison, rats lesioned either in the ventral hippocampus or the dorsal hippocampus at the age of 8 weeks were tested. METHODS: Rats on day 7 of age were lesioned with ibotenic acid in the ventral hippocampus and social behaviour was tested at the age of 13 weeks. For comparison, adult 8-week-old rats were lesioned either in the ventral or the dorsal hippocampus. Their social behaviour was tested at the age of 18 weeks. RESULTS: It was found that neonatal lesion resulted in significantly decreased time spent in social interaction and an enhanced level of aggressive behaviour. This shift is not due to anxiety because we could not find differences between control rats and lesioned rats in the elevated plus-maze. Lesion in the ventral and dorsal hippocampus, respectively, in 8-week-old rats did not affect social behaviour. CONCLUSIONS: The results of our study indicate that ibotenic acid-induced hippocampal damage per se is not related to the shift in social behaviour. We favour the hypothesis that these changes are due to lesion-induced impairments in neurodevelopmental processes at an early stage of ontogenesis.

Aggression↗

PubMed1999

Alterations of the dopaminergic and glutamatergic neurotransmission in adult rats with postnatal ibotenic acid hippocampal lesion.

In 6-week and 8-week-old rats (pre- and post-pubertally) with neonatal excitotoxic lesions of the ventral hippocampus with ibotenic acid (IBO), we have studied apomorphine-induced motor activity and glutamate and dopamine D1 and D2 binding sites in the hippocampus, striatum, nc. accumbens and frontal cortex as well as K+ -stimulated (3H)-D-aspartate release from hippocampal and frontal cortical slices. Specific glutamate binding was enhanced in the frontal cortex of 8-week-old IBO-treated animals, whereas that in other brain regions remained unchanged. Both D1 and D2 binding sites were downregulated in the striatum without changes in other brain structures. In 6-week-old rats, neither the glutamate nor the dopamine binding sites were altered. The amino acid release from hippocampal and frontal cortical slices of adult IBO treated rats was significantly decreased in comparison to controls, whereas in 6-week-old rats, no significant alterations were detectable. The additionally monitored motor activity was enhanced only in adult IBO-lesioned rats after apomorphine pretreatment. The present data are in agreement with the hypothesis of hyperactive dopamine and hypoactive glutamate systems in schizophrenia and are discussed in the light of schizophrenia-like behavioral changes in rats after postnatal hippocampal IBO lesion.

Age Factors↗

PubMed1999

Detection and quantification of coronary artery calcification with electron-beam and conventional CT.

To identify patients with increased risk of having coronary artery disease (CAD), electron-beam computed tomography (EBCT) was used for years for quantifying calcifications of the coronary arteries. The first direct comparison between EBCT and conventional CT was performed to determine the reliability of widely available conventional CT for the assessment of the coronary calcium score. Fifty male patients with suspected CAD were investigated with both modalities, EBCT and conventional 500-ms non-spiral partial scan CT. Scoring of the coronary calcification was performed according to the Agatston method. Forty-two of these patients underwent coronary angiography for the assessment of significant luminal narrowing. The correlation coefficient of the score values of both modalities was highly significant (r = 0.982, p < 0.001). The variability between the two modalities was 42%. Mean calcium score in patients with significant coronary luminal narrowing (n = 37) was 1104 +/- 1089 with EBCT and 1229 +/- 1327 with conventional CT. In patients without luminal narrowing (n = 5) mean calcium score was 73 +/- 57 with EBCT and 26 +/- 35 with conventional CT. Although images of the heart from conventional CT may suffer from cardiac motion artifacts, conventional CT has the potential to identify patients with CAD with accuracy similar to EBCT.

Artifacts↗

PubMed1999

The eff-482 locus of Sinorhizobium meliloti CXM1-105 that influences symbiotic effectiveness consists of three genes encoding an endoglycanase, a transcriptional regulator and an adenylate cyclase.

The mutant T482 of Sinorhizobium meliloti CXM1-105, which carries a Tn5 insertion on megaplasmid 1, exhibits an enhanced symbiotic efficiency phenotype. Three genes, eglC, cya3 and syrB2, were identified in the eff-482 region tagged by the Tn5 insertion in T482. The eglC gene encodes an endoglycanase which contributes to the depolymerization of the exo-polysaccharide succinoglycan. The N-terminal region of the predicted cya3 gene product was similar to eukaryotic-type adenylate cyclases from Brevibacterium liquefaciens and Streptomyces coelicolor. Four contiguous tetratricopeptide repeats which are known to mediate protein-protein interactions were identified in the C-terminal portion of Cya3. Complementation analysis demonstrated that cya3 indeed encodes a functional adenylate cyclase. A central helix-turn-helix DNA-binding motif and a putative C-terminal coiled-coil structure implicated in protein oligomerization were found in SyrB2. Extra copies of the syrB2 gene negatively affect transcription of both syrB2 itself and cya3. The Tn5 insertion in T482 was localized between the divergently transcribed genes eglC and syrB2. It eliminated eglC function and slightly stimulated transcription of both syrB2 and cya3, which lies downstream of syrB2. Mutants carrying insertions of the lacZ-Gm interposon in the genes eglC, syrB2 and cya3 exhibit the same phenotype as mutant T482, indicating that these three genes influence symbiotic efficiency.

Adenylyl Cyclases↗

PubMed1999

Role of autacoids in cardiovascular colapse in anaphylactic shock in anaesthetized dogs.

OBJECTIVE: In anaphylactic shock (AS), the relative effects of the autacoids including histamine, prostaglandins (prost), and leukotrienes (leuk) on causing cardiovascular collapse and the extent to which receptor blocking agents and pathway inhibitors may prevent this collapse are not clear. METHODS: In randomized design, we investigated whether blockade of histamine H1, H2, and H3 receptors or inhibition of the cyclooxygenase (cyclo) and lipoxygenase pathways (lipox) prevented AS in ragweed sensitized dogs. Seven dogs were studied under pentobarbital anesthesia in which the treatment studies were approximately 2 weeks apart. RESULTS: During H1 receptor blockade, the decreases in blood pressure and cardiac output otherwise observed in AS were attenuated (P < 0.05) and the release of prost, thromboxanes, and leuk were reduced as compared with nontreatment studies. Cyclo inhibition also attenuated cardiovascular collapse and mediator release in AS, but the other treatments showed no effects. CONCLUSION: H1 receptor blockade and cyclo may attenuate cardiovascular shock in AS. These agents inhibit autacoid release from mast cells in addition to any specific receptor blocking and pathway inhibition effects.

Analysis of Variance↗

PubMed1999

3H-L-glutamate binding and 3H-D-aspartate release from hippocampal tissue during the development of pentylenetetrazole kindling in rats.

Previous studies have proposed that there is an increase in the density of glutamate binding sites after pentylenetetrazol (PTZ) kindling, whereas the glutamate release is not altered. Little is known about the time course of these changes. Therefore, we studied 3H-L-glutamate binding to hippocampal membranes and K+-stimulated 3H-D-aspartate release from hippocampal slices of rats given PTZ 3, 7, and 13 times up to a fully kindling state. After three PTZ injections, amino acid release from hippocampal tissue slices was significantly enhanced in comparison to controls, whereas 3H-L-glutamate binding was not altered. After seven injections of PTZ, specific glutamate binding to hippocampal membranes tended to increase, and K+-stimulated 3H-D-aspartate release from rat hippocampal slices was normalized. The kindled state characterized by generalized clonic-tonic seizures was reached after 13 PTZ injections, and it was accompanied by an enhancement in the density of glutamate binding sites, whereas the chemically evoked amino acid release remained unchanged. It can be concluded that the amino acid release is increased in the early phase of PTZ kindling development, whereas after completion of kindling, the density of excitatory amino acid binding sites is enhanced.

Animals↗

PubMed1999

Umbilical cord blood mononuclear cell proliferative response to house dust mite does not predict the development of allergic rhinitis and asthma.

BACKGROUND: Cord blood mononuclear cells (CBMNCs) have been found to proliferate when stimulated with food or inhalant allergens. The significance of this finding is not known. OBJECTIVES: We sought to determine the factors associated with proliferation of CBMNCs when stimulated with house dust mite (HDM) allergen and to determine whether proliferation of CBMNCs is associated with subsequent development of HDM sensitization and development of allergic rhinitis and asthma. METHODS: Cord blood was taken from infants at high risk for having asthma and allergic diseases who were recruited for a primary prevention study in which infants were randomized into the intervention or the control group. CBMNCs were stimulated with HDM allergen and PHA as a positive control. Infants were assessed at 12 and 24 months for health outcome. RESULTS: When stimulated with HDM allergen, 29.7% of infants had a stimulation index (SI) of 2 or greater. There were no differences in the levels of cord blood IgE and cotinine, maternal smoking, immediate skin test reactivity, maternal IgE, and maternal exposure to HDM allergen between those with an SI of 2 or greater and those with an SI of less than 2. Infants with an SI of less than 2 had a significantly higher proportion of mothers with a history of asthma. No differences in the incidence of "asthma" and rhinitis without cold at 12 months and cumulative prevalence at 24 months were seen between the 2 groups. None of the infants had skin test reactions to HDM allergen. CONCLUSION: The negative association between HDM allergen-induced proliferation of CBMNCs and maternal mite allergen exposure and health outcomes at 12 and 24 months raises the issue of the significance of CBMNC proliferation.

Allergens↗

PubMed1999

Disruption of latent inhibition in rats with postnatal hippocampal lesions.

Disruption of latent inhibition has been proposed as a possible model of cognitive abnormalities that underlie positive symptoms of a schizophrenia. We tested neonatal hippocampal lesioned rats in a latent inhibition paradigm. Lesions of the ventral hippocampus were induced by bilateral injections of ibotenic acid in 7 days old rats. The behavior of lesioned rats was tested postpubertally. We found a hyperresponsiveness to dopaminergic stimulation by apomorphine in locomotion tests. Latent inhibition was tested using the acquisition of a conditioned reaction in a two-way shuttle box. Sham operated control animals showed after preexposure of the to-be-conditioned stimulus (combined tone and light stimulus) a low acquisition. Ibotenic acid lesioned animals learned the conditioned reaction with and without preexposure in the same way, indicating disturbed latent inhibition. These results demonstrate disturbances in early postnatal hippocampal lesioned rats comparable with those seen in schizophrenic patients, thus further validating this procedure as a useful animal model of some aspects of schizophrenia.

Anesthesia↗

PubMed1999

The use of panoramic radiographs to localize displaced maxillary canines.

OBJECTIVE: The purpose of this investigation was to develop a reliable method of diagnosing the position of a displaced maxillary canine on the basis of a single panoramic radiograph. STUDY DESIGN: A total of 115 panoramic radiographs depicting 164 displaced maxillary canines were evaluated. The ratio of the width of the displaced canine to the width of the homolateral central incisor (the canine-incisor index) and the ratio of the width of the displaced canine to the width of the contralateral canine (the canine-canine index) were calculated. The height of the crown of each displaced canine was classified in the vertical plane, relative to the adjacent incisor, as apical, middle, or coronal. RESULTS: There was an overlap in the canine-incisor index ranges of the buccal (0.94-1. 45) and palatal (1.15-1.29) canines in the apical zone. In the middle and coronal zones, a clear difference could be seen between the canine-incisor indices of labially (0.78-1.11) and palatally (1.15-1.7) located canines. A cut-off point of 1.15 was determined. CONCLUSIONS: Provided that vertical restriction and the canine-incisor index are used, the panoramic radiograph can serve as a useful indicator for determining the position of an unerupted maxillary canine.

Adolescent↗

PubMed1999

Clinical practice guidelines for the use of albumin: results of a drug use evaluation in a Paris hospital. Tenon Hospital Paris.

Clinical practice guidelines on the prescription of albumin were instituted in our hospital according to a method which combined a review of the medical literature with experts points of view. Their broadcasting was based upon a daily patient-specific decision support which was well-documented by the prescribing physician. The method for assessing the impact was a six month analysis of the discrepancies between recommendations and clinical practice. Results were a better compliance with guidelines (25.5% before and 59% after developing recommendations), a decrease 70% in grams of albumin prescribed and in use of an increase synthetic colloids, and a savings of $57,208 per year.

Blood Volume↗

PubMed1999

Structure and mechanism of the glycyl radical enzyme pyruvate formate-lyase.

Pyruvate formate-lyase (PFL) from Escherichia coli uses a radical mechanism to reversibly cleave the C1-C2 bond of pyruvate using the Gly 734 radical and two cysteine residues (Cys 418, Cys 419). We have determined by X-ray crystallography the structures of PFL (non-radical form), its complex with the substrate analog oxamate, and the C418A,C419A double mutant. The atomic model (a dimer of 759-residue monomers) comprises a 10-stranded beta/alpha barrel assembled in an antiparallel manner from two parallel five-stranded beta-sheets; this architecture resembles that of ribonucleotide reductases. Gly 734 and Cys 419, positioned at the tips of opposing hairpin loops, meet in the apolar barrel center (Calpha-Sgamma = 3.7 A). Oxamate fits into a compact pocket where C2 is juxtaposed with Cys 418Sgamma (3.3 A), which in turn is close to Cys 419Sgamma (3.7 A). Our model of the active site is suggestive of a snapshot of the catalytic cycle, when the pyruvate-carbonyl awaits attack by the Cys 418 thiyl radical. We propose a homolytic radical mechanism for PFL that involves Cys 418 and Cys 419 both as thiyl radicals, with distinct chemical functions.

Acetyltransferases↗

PubMed1999

Impact of guidelines implemented in a paris university hospital: application to the use of antiemetics by cancer patients.

AIMS: To assess the impact with time of guidelines on antiemetic use in an 850-bed Paris university hospital with a high proportion of cancer patients. METHODS: Guidelines on the use of antiemetics available in cancer chemotherapy were drafted according to the Delphi technique. Their implementation was based upon a patient-specific antiemetic prescription form. To assess the impact of guideline implementation over time, discrepancies between current practice and the guidelines were compared before guideline implementation (between March and August 1995) and after implementation (between March and August 1997, and March and August 1998). RESULTS: Before the Delphi panel's guidelines were implemented, 5-HT3 antagonists were inappropriately administered in 70% of cases. After guideline implementation, this proportion dropped significantly (P<0.0001, Fisher's exact test) to 22% between March and August 1997 and 28% between March and August 1998. CONCLUSIONS: Implementation of guidelines seems to have resulted in significant changes with time, although a causal relationship has not been demonstrated. The development of guidelines by our hospital's multidisciplinary working group helped the various consultants to adjust medical practices to take account of these changes.

Academic Medical Centers↗

PubMed1999

Living anatomy of the atrioventricular junctions. A guide to electrophysiological mapping. A Consensus Statement from the Cardiac Nomenclature Study Group, Working Group of Arrythmias, European Society of Cardiology, and the Task Force on Cardiac Nomenclature from NASPE. North American Society of Pacing and Electrophysiology.

Current nomenclature for atrioventricular junctions derives from a surgically distorted view, placing the valvar rings and the triangle of Koch in a single plane with antero-posterior and right-left lateral coordinates. Within this convention, the aorta is considered to occupy an anterior position, while the mouth of the coronary sinus is shown as being posterior. While this nomenclature has served its purpose for the description and treatment of arrhythmias dependent on accessory pathways and atrioventricular nodal re-entry, it is less than satisfactory for the description of atrial and ventricular mapping. To correct these deficiencies, a consensus document has been prepared by experts from the Working Group of Arrhythmias of the European Society of Cardiology, and the North American Society of Pacing and Electrophysiology. It proposes a new, anatomically sound, nomenclature that will be applicable to all chambers of the heart. In this report, we discuss its value as regards the description of the atrioventricular junctions, establishing the principles of this new nomenclature.

Atrioventricular Node↗

PubMed1999

Effect of 1alpha,25(OH)2-vitamin D3 on TNF alpha-mediated apoptosis of human primary osteoblast-like cells in vitro.

1alpha,25(OH)2-vitamin D3 is a hormone which potentially stimulates bone cell growth and differentiation. TNFalpha is one possible inductor for apoptosis; apoptosis being an important regulatoring factor for bone modelling and remodelling. We examined the influence of physiological levels (0.1 nM) 1alpha,25(OH)2-vitamin D3 on TNFalpha-mediated apoptosis in human osteoblast-like cells. These human cells were obtained from bone fragments obtained during orthopedic operations on patients without systemic bone disease. Treatment with 1alpha,25(OH)2-vitamin D3 for 8 weeks resulted in a significant reduction (30%) of viable cell number compared to untreated cells. Incubation with TNFalpha (100 ng/ml for 4 hours) only had limited effects on the rate of apoptosis in control cells. After pretreatment with 1alpha,25(OH)2-vitamin D3, induction of apoptosis increased up to 10% in human osteoblast-like cells. In parallel to the induction of apoptosis, 1alpha,25(OH)2-vitamin D3 stimulated osteocalcin and alkaline phosphatase as markers of mature osteoblasts. Our data suggest that 1alpha,25(OH)2-vitamin D3 has a stimulatory effect on TNFalpha-induced apoptosis in human osteoblast-like cells as a result of 1alpha,25(OH)2-vitamin D3-induced cell differentiation.

Alkaline Phosphatase↗

PubMed1999

Peripheral blood mononuclear cells promote intestinal epithelial restitution in vitro through an interleukin-2/interferon-gamma-dependent pathway.

BACKGROUND: Acute intestinal mucosal inflammation is associated with recruitment of peripheral blood mononuclear cells (PBMN) into the mucosa and migration across the epithelium. It has recently been shown that several PBMN-derived cytokines, including transforming growth factor-beta (TGF-beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-2 (IL-2), and interferon-gamma (IFN-gamma) may modify intestinal epithelial cell function, resulting in rapid improvement of wound repair. Our aim was to characterize the modulating effects of PBMN on intestinal epithelial restitution, the initial step of wound healing. METHODS: PBMN were separated from whole blood, obtained from healthy volunteers, by using a density gradient. The effect of PBMN on intestinal epithelial restitution was assessed by using an in vitro coculture wounding model with non-transformed small-intestinal epithelial IEC-6 cells. RESULTS: Coculture of PBMN caused a significant enhancement of epithelial cell restitution in vitro. The modulatory effects of PBMN could be significantly blocked by adding immunoneutralizing anti-IL-2 or anti-IFN-gamma to the culture media, suggesting that PBMN may modulate intestinal epithelial migration through an IL-2- and IFN-gamma-dependent pathway. In contrast, PBMN-induced stimulation of intestinal epithelial restitution was not influenced by addition of anti-TGF-beta or anti-TNF-alpha, suggesting that these cytokines are not critical for the modulation of restitution by PBMN. CONCLUSIONS: These findings suggest that PBMN may promote intestinal epithelial wound repair by enhancing restitution through secretion of various cytokines, among them IL-2 and IFN-gamma, which are abundantly expressed in the course of several inflammatory diseases of the gut.

Animals↗

PubMed1999

Mutation analysis of core binding factor A1 in patients with cleidocranial dysplasia.

Cleidocranial dysplasia (CCD) is a dominantly inherited disorder characterized by patent fontanelles, wide cranial sutures, hypoplasia of clavicles, short stature, supernumerary teeth, and other skeletal anomalies. We recently demonstrated that mutations in the transcription factor CBFA1, on chromosome 6p21, are associated with CCD. We have now analyzed the CBFA1 gene in 42 unrelated patients with CCD. In 18 patients, mutations were detected in the coding region of the CBFA1 gene, including 8 frameshift, 2 nonsense, and 9 missense mutations, as well as 2 novel polymorphisms. A cluster of missense mutations at arginine 225 (R225) identifies this residue as crucial for CBFA1 function. In vitro green fluorescent protein fusion studies show that R225 mutations interfere with nuclear accumulation of CBFA1 protein. There is no phenotypic difference between patients with deletions or frameshifts and those with other intragenic mutations, suggesting that CCD is generally caused by haploinsufficiency. However, we were able to extend the CCD phenotypic spectrum. A missense mutation identified in one family with supernumerary teeth and a radiologically normal skeleton indicates that mutations in CBFA1 can be associated exclusively with a dental phenotype. In addition, one patient with severe CCD and a frameshift mutation in codon 402 had osteoporosis leading to recurrent bone fractures and scoliosis, providing first evidence that CBFA1 may help maintain adult bone, in addition to its function in bone development.

Bone and Bones↗