Search PubMed⌕ Search

Biomedical subjects

H Steiner

Publications and source records attributed to H Steiner.

At least 235 records · Page 13Linked to original sources
PubMed1989

[MR tomography following lumbar disk surgery: differential diagnostic potentials using Gd-DTPA].

55 patients were examined by magnetic resonance imaging after lumbar disk operation. The results indicate that with Gd-DTPA there is a significantly increased signal intensity along the surgical approach directly after surgery and during the early postoperative period. Whereas herniated or sequestered disk did not enhance with Gd-DTPA, in epidural fibrosis - regardless of the age of the scarification - diagnostic enhancement was obvious. In 82 percent nerve roots engulfed by scar tissue were differentiated after Gd-DTPA; even enlarged nerve roots and changes of arachnoiditis could be differentiated from each other.

Contrast Media↗
PubMed1989

Native and mutant 5-lipoxygenase expression in a baculovirus/insect cell system.

Human 5-lipoxygenase (EC 1.13.11.34), the key enzyme involved in the transformation of arachidonic acid to the potent biologically active leukotrienes, has been overexpressed in insect cells using a baculovirus expression system. A recombinant baculovirus (3B6) carrying the human 5-lipoxygenase coding sequence downstream of the strong polyhedrin protein promoter was isolated. Approximately 48 hr after infection of Spodoptera frugiperda cells with the recombinant baculovirus, maximal intracellular enzyme activity and protein levels were detected. The recombinant 5-lipoxygenase in 10,000 x g supernatant fractions was able to synthesize large amounts of 5-hydroperoxy-6,8,10,14-icosatetraenoic acid, together with smaller amounts of the nonenzymatic hydrolysis products of leukotriene A4, and exhibited a dependence on Ca2+ and ATP for maximal activity. Immunoblot analysis of supernatant proteins from human leukocytes and recombinant virus-infected cells indicated the presence of indistinguishable approximately 80-kDa bands. However, 5-lipoxygenase protein in recombinant-infected cells was found to be present in amounts 50-200 times that present in leukocytes on a per-cell basis. Histidine-362 and histidine-372, potential iron-atom ligands within a putative iron-binding domain, were changed to serine residues. Recombinant baculoviruses carrying the mutations were isolated and used to infect insect cells. Although infected cells were able to express mutant 5-lipoxygenase protein, enzyme activity was not substantially altered, suggesting the nonessential nature of these histidines in binding iron at the putative ferric catalytic site.

Arachidonate 5-Lipoxygenase↗
PubMed1989

Cardiovascular effects of desipramine in children.

The effect of desipramine hydrochloride was studied in children who were treated for eating disorders (5), attention deficit disorder (13), or affective disturbance (3). Serial heart rate, blood pressure, ECG, and 24-hour ambulatory monitoring were recorded before treatment and at 4 and 8 weeks during treatment. Maximum dose of desipramine was 5 mg/kg/day, average 4.25. A 21% increase in heart rate and 2.5% increase in QTc at 4 weeks were sustained at 8 weeks. No dysrhythmias or clinically significant changes in blood pressure occurred. Desipramine is safe in children who have normal cardiovascular examinations and ECGs when used within the limits of the study design. The cardiovascular effects of desipramine should be kept in mind and monitored when patients are starting tricyclic antidepressant therapy such as desipramine.

Arrhythmias, Cardiac↗
PubMed1989

[Conventional and computed tomographic findings in polysplenia syndrome].

A case of polysplenia syndrome associated with abdominal situs inversus and anomalies of the inferior vena cava system is demonstrated by conventional and CT examinations. The conventional radiographic findings already suggest the diagnosis; final verification can be achieved via computed tomography.

Adult↗
PubMed1988

Human tissue-type plasminogen activator synthesized by using a baculovirus vector in insect cells compared with human plasminogen activator produced in mouse cells.

A cDNA fragment encoding the human tissue-type plasminogen activator was inserted into the baculovirus Autographa californica nuclear polyhedrosis virus downstream from the polyhedrin promoter. The induction kinetics of t-PA was followed, after infection of Spodoptera frugiperda cells, at both mRNA and protein levels. Fibrinolytically active plasminogen activator accumulated in the culture medium and reached 2.5 micrograms/ml after 120 h. The protein was compared with recombinant plasminogen activator produced in mouse cells and was found to be slightly smaller. This difference in size was found to be caused by N-linked oligosaccharides which are shorter in the recombinant activator obtained from insect cells. The molecules produced in such cells contain at least two different types of N-linked glycans, since only one out of three oligosaccharides is sensitive to endoglycosidase H. However, all glycan structures bind strongly to concanavalin A-Sepharose.

Animals↗
PubMed1988

Binding and action of cecropin and cecropin analogues: antibacterial peptides from insects.

The mechanism of action of cecropin was studied by using liposomes as a model system. The bilayer was efficiently destroyed if the liposome net charge was zero or negative. Cecropin analogues with an impaired N-terminal helix had reduced membrane disrupting abilities that correlate with their lower antibacterial activity. The reduced bactericidal activity of the analogues was rationalized in terms of reduced binding to bacteria. The stoichiometry of cecropin killing of bacteria suggests that amounts of cecropin sufficient to form a monolayer strongly modify the bacterial membrane. Although some bacteria were resistant to cecropin they did bind large amounts in a non-productive manner. In contrast, mammalian erythrocytes achieve resistance by avoiding the binding of cecropin.

Animals↗
PubMed1988

Lateralized wall-facing versus turning as measures of behavioral asymmetries and recovery of function after injection of 6-hydroxydopamine into the substantia nigra.

The tendency of a rat to approach the wall of an open-field and to travel along the perimeter of the field (termed as "peritaxis" or "wall-facing") is affected by unilateral removal of the vibrissae. Peritaxis is lateralized by hemivibrissotomy. The finding that the dopamine agonist apomorphine reversed the direction of wall-facing asymmetry after 10 days of vibrissae removal suggested a link between this sensorimotor asymmetry and dopamine transmission. The present experiment examined the influence of a unilateral injection of 6-hydroxydopamine into the substantia nigra on peritaxis and compared this behavioral measure with turning behavior as an index of lesion-induced sensorimotor asymmetries and of recovery of function. The lesion of the substantia nigra reduced wall-facing with the side contralateral to the lesion to near-zero values. During the first week after the injection animals with incomplete dopamine depletion recovered from this asymmetry. The changes in wall-facing behavior were paralleled by turning asymmetries. Wall-facing was at least as sensitive to application of amphetamine and apomorphine as turning behavior. We concluded that lateralized wall-facing, or peritaxis, can serve as a useful index of dysfunction in the nigrostriatal dopamine system and the influence of catecholaminergic drugs. Wall-facing can also serve as a measure of recovery of function.

Animals↗
PubMed1988

Family environment of adolescents and coping in the hospital.

The purpose of this study was to test the relationship between social environment and the activity of the HPA axis in adolescents. Ten elective admissions to Children's Hospital at Stanford were assessed by standard psychiatric interview. Five fulfilled criteria for a DSM-III diagnosis, five others did not. The groups were comparable in age, height, weight, SES, and number of previous hospitalizations. All subjects and their families completed the Family Environment Scale. All subjects had plasma cortisol concentrations determined on days 1, 3, and 5 of hospitalization and at the time of discharge. Samples were drawn under standardized conditions, after a brief interview during which potentially stressful events of the day were discussed. Results revealed that the five individuals with poor coping skills, as defined by the presence of a DSM-III diagnosis, had significantly higher peak concentrations of plasma cortisol, than the five psychiatrically normal subjects. Peak cortisol elevations occurred upon discharge from the hospital. Family environment in the two groups differed significantly on the dimensions of cohesion, conflict, control, and incongruence of perception of the environment among family members themselves. The findings support the hypothesis that social environmental characteristics are associated with psychiatric and physiological measures of coping.

Adaptation, Psychological↗
PubMed1988

Description and recording physical signs in suspected child sexual abuse.

The identification of child sexual abuse may depend on the accurate interpretation of abnormal physical signs. Therefore, it is necessary to have a consistent vocabulary and a full and accurate record of the findings (Report of the Inquiry into Child Abuse in Cleveland 1987). Our suggestions are intended to promote the development of a standard acceptable to all concerned with these problems.

Child↗
PubMed1987

Video image analysis of behavior by microcomputer: categorization of turning and locomotion after 6-OHDA injection into the substantia nigra.

The automated video image analyzing system (VIAS) measures locomotion in meters and turning behavior of rats by digitized video image and microcomputer evaluation. To measure turning behavior the number of 1/4, 1/2, 3/4 and complete turns are recorded. The turns are classified in different diameter classes. To test the validity of this system rats were administered unilateral 6-OHDA lesions of the substantia nigra and were observed by human rater and VIAS in parallel. Correlation coefficients for the data obtained by both methods were r = 0.98 for locomotion, r = 0.93 for half turns with diameter greater than or equal to 30 cm. Recovery from lesion-induced turning of animals with striatal dopamine depletion of 81.4% to 87.2% was described in detail by VIAS with respect to the diameter of the turns. It is concluded that VIAS provides a potent tool for the analysis of turning behavior and locomotion.

Animals↗
PubMed1987

[Computerized tomography and myelography findings following lumbar intervertebral disk surgery].

56 patients suspected of having suffered recurrent disc prolapse in the lumbar region were examined by CT and by myelography; the value of these examinations has been analysed. In 32 patients the findings were checked during surgery. There were difficulties in diagnosis, both for CT and myelography, where the findings were complex, i.e. in patients in whom there was postoperative fibrosis as well as disc prolapse and/or osseous spinal canal stenosis. As regards recurrence of prolapse, sensitivity for both methods was 83%. Postoperative scar formation can be clearly demonstrated by CT, but myelography produced a false positive diagnosis of recurrent prolapse in 17%. The changes were, in fact, caused by scar tissue formation.

Cicatrix↗
PubMed1987

[Cerebral manifestations in non-Hodgkin lymphoma and in lymphogranulomatosis on the CT image].

Primary or secondary cerebral non-Hodgkin-lymphoma or Hodgkin's disease are very rare. The incidence varies from 0.2 to 4%. There is a predilection for the basal ganglia, corpus callosum, thalami and subependymal regions. Hodgkin's disease involving the brain usually infiltrates from the meninges. Solitary tumors are rare, multifocal tumors are extremely unusual. The typical CT appearances of intracranial lymphomas are described in three cases. These consist of isodense or hyperdense intracerebral lesions with marked increase in density on contrast enhancement. Periventricular tumor expansion in NHL is characteristic.

Aged↗
PubMed1986

Health surveillance of preschool children.

Discussions with every general practice, health visitor, and clinical medical officer in Northumberland Health Authority led to agreement about the content of preschool health surveillance, the ages at which it should be done, and referral pathways after a failed screening test. Each primary health care team now undertakes to do a basic minimum set of screening tests, and each team decides who in the team will do each test. The screening system agreed on should enable time to become available for the equally important aspects of surveillance--namely, developmental guidance, health education, and assessment and follow up of problems. The discussions also led to agreement about how the health authority should evaluate the effect of the surveillance programme on the health of children.

Child Guidance↗