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Biomedical subjects

A Schultz

Publications and source records attributed to A Schultz.

At least 163 records · Page 9Linked to original sources
PubMed1983

Joint flexibilities in structurally normal girls and girls with idiopathic scoliosis.

Seven clinical measurements of joint flexibilities were made in 51 girls with untreated mild idiopathic scoliosis and 65 girls with structurally normal spines. Subject ages ranged from 10 to 16 years. Abilities to have the index finger passively extended, the wrist bent, and the elbow and the knee hyperextended, along with abilities to bend the trunk voluntarily forward and to the right and left sides, were measured. The girls with scoliosis in the mean either had the same flexibilities or were less flexible than the normal girls. The study provided no evidence that untreated mild idiopathic scoliosis occurs or progresses because of increased joint flexibilities.

Adolescent↗
PubMed1983

Use of lumbar trunk muscles in isometric performance of mechanically complex standing tasks.

Ten subjects performed 25 tasks isometrically while standing. Those tasks imposed substantial extension, lateral bending, and twisting moments on the lumbar spine. Mechanically complex trunk muscle actions were called for to resist those moments. Biomechanical model analyses were used to predict the trunk muscle contraction forces needed to perform those tasks, and surface myoelectric activities were measured to validate those predictions. Predictions and measurements were linearly well correlated.

Adult↗
PubMed1983

Biological, chemical, and immunological studies of Rauscher ecotropic and mink cell focus-forming viruses from JLS-V9 cells.

Two murine leukemia viruses were isolated from JLS-V9 cells which had been infected with Rauscher plasma virus. One virus was XC positive and failed to grow on mink or cat cells and thus was an ecotropic virus. The other virus formed cytopathic foci on mink cells, was XC negative, and fell into the mink cell focus-forming (MCF) viral interference group and was thus an MCF virus. The glycoproteins of the two viruses could be distinguished immunologically, by peptide mapping, and by size in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The MCF virus produced gp69, and the ecotropic virus produced gp71, explaining the origin of the heterogeneous glycoprotein (gp69 and gp71) of Rauscher leukemia virus. Amino-terminal sequences of gp69 and gp71 were determined. The MCF sequence was distinct from the ecotropic sequence, but retained partial homology to it. The data show that the glycoproteins are encoded by related yet distinct genes. The protein structural data support the proposal that MCF virus gp70 molecules have nonecotropic sequences at the amino terminus, with ecotropic sequences occurring at the 3' end of the gene. The Rauscher MCF virus glycoprotein lacks a glycosylation site found at position 12 of the ecotropic sequence.

Animals↗
PubMed1983

Mechanical effectiveness studies of lumbar spine orthoses.

Intradiscal pressures, intra-gastric pressures and myoelectric trunk muscle activities were measured in four volunteers wearing five different orthoses of three principle types, and performing six tasks. A biomechanical model was used to estimate the load on the spine in the different tasks so as to compare those tasks reliably when done with and without the orthoses. The results indicate that wearing a brace can significantly unload the trunk in some situations, but has no effect in others. Lumbar spine compression was reduced by about one-third in the task involving trunk flexion. The disc pressure values with an orthosis were lower in about two-thirds of the exercises and higher in the remaining one-third. The back muscle activity was in some experiments reduced by one-third by the use of the brace, in others it increased by the same amount. None of the orthoses raised the intra-gastric pressure significantly. No one orthosis was found to be clearly superior in mechanical effectiveness in the tasks studied.

Adult↗
PubMed1983

Septic complications after appendicectomy for perforated appendicitis. A controlled clinical trial metronidazole and topical ampicillin.

A prospective, controlled trial of antibiotic therapy was carried out in 90 patients with perforated appendicitis. One randomly selected group received systemic metronidazole, started peroperatively, plus locally instilled ampicillin. The other group, also randomly selected, received only local ampicillin. There was no statistically significant difference in the overall frequency of postoperative septic complications (wound infection or intra-abdominal abscess) between the two groups, but wound infections were significantly fewer in the patients given metronidazole. There was no intergroup difference in hospitalization time. Treatment with systemic metronidazole and local ampicillin is recommended in patients operated on for perforated appendicitis.

Adolescent↗
PubMed1982

Loads on the lumbar spine. Validation of a biomechanical analysis by measurements of intradiscal pressures and myoelectric signals.

UNLABELLED: We studied the validity of predictions of compressive loads on the lumbar spine and contraction forces in lumbar trunk muscles based on a biomechanical model. The predictions were validated by quantitative measurements of myoelectric activities at twelve locations on the trunk and of the pressure in the third lumbar disc. Twenty-five tasks were performed isometrically by four healthy volunteers. The model predicted that the tasks imposed mean compressive loads on the spine of as much as 2400 newtons and required contraction forces of the posterior muscles of the back of as much as 1800 newtons. Intradiscal pressures of as much as 1600 kilopascals were measured. The predicted and measured quantities were well correlated. It appears that the model adequately predicted the compressive loads on the lumbar spine and the tensions in the back muscles. CLINICAL RELEVANCE: Patients with low-back disorders limit their physical activities, which indicates that loading on the spine must be a factor in those disorders. This study shows that the loads imposed on the spine by physical activities need not be measured. They can easily be calculated. This will significantly accelerate biomechanics research on low-back disorders. The calculation techniques that we validated for predicting loads on the spine can be used to calculate the loads on any skeletal structure. Those loads are largely determined not by the externally applied loads, but by the moments of those applied loads and by the moments of the weights of the body segments that the structure must support.

Abdomen↗
PubMed1981

Infusion of vasoactive intestinal polypeptide in man: pharmacokinetics and effect on gastric acid secretion.

Elimination and effect on acid secretion of vasoactive intestinal polypeptide (VIP) were studied in six healthy volunteers. On a background infusion of pentagastrin, 100 ng/kg-h, VIP was administered as stepwise intravenous infusions in doses of 0.5, 0.9, and 2.7 micro/g/kg-h, each dose being give for 1 h. Mean plasma VIP concentrations rose from 5.7 pmol/l to 28, 106 and 336 pmol/l during the VIP infusions. No significant changes in acid secretion occurred during VIP infusion as compared to infusion of pentagastrin alone, and no duodeno-gastric reflux was registered. Serum gastrin concentrations were unaltered during VIP infusion. Elimination of VIP was bi-exponential with half-lives of 2 and 21 min, respectively. Metabolic clearance rate was 42 ml/kg-min and the estimated volume of distribution 135 ml/kg.

Adult↗
PubMed1981

Silver nitrate pleurodesis in spontaneous pneumothorax.

Pleurodesis provoked by instillation of silver nitrate as prevention against recurrence in primary spontaneous pneumothorax has been used for many years in the Department of Thoracic Surgery, Gentofte Hospital, University of Copenhagen. The treatment was originally instituted on a theoretical empiric basis. In a prospective, controlled investigation of pleurodesis versus simple drainage the empiric observations have been confirmed. With simple drainage we found ipsilateral recurrence of pneumothorax in 45%, while no recurrences in the pleurodesis group were found during an observation period of 5-19 months. The difference was statistically significant. The therapeutical gain using pleurodesis was 45% +/- 30%. Silver nitrate pleurodesis results in a longer hospitalization, raises the number of pleurocentesis because of increased pleural effusion and results in more pain than simple drainage. It is, however, our experience that the considerable therapeutical gain more than compensates for these negative effects. We recommend pleurodesis as the treatment of choice in primary spontaneous pneumothorax in patients with only tiny blebs on the surface of the lungs.

Adolescent↗