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Biomedical subjects

F Schultz

Publications and source records attributed to F Schultz.

17 recordsLinked to original sources
PubMed2000

Mechanical properties of the posterior rotator cuff.

BACKGROUND: The infraspinatus is an important active and passive stabilizer of the glenohumeral joint. It functions as external rotator and participates in elevation of the arm. As its main posterior component, it is frequently involved in rotator cuff tears. OBJECTIVE: The purpose of this study was to determine the structural and mechanical properties of the infraspinatus tendon structure, including the midsubstance and insertion regions, in the superior, mid-superior, mid-inferior, and inferior portions, in two joint positions. METHODS: The infraspinatus tendons from 22 fresh frozen cadaver shoulders were divided into four strips. The tendons were held in a cryo-jaw and tested with a material-testing machine in 0 degrees or 60 degrees of glenohumeral abduction corresponding to 90 degrees arm abduction. Ultimate load, displacement and failure mode were recorded. Stiffness, ultimate stress and elastic modulus were calculated. RESULTS: Significant differences between glenohumeral abduction positions were detected only for the elastic modulus. The mid-superior (676.5 N, S.D. 231.0 N) and the inferior portion (549.9 N, S.D. 284.6 N) had the highest failure loads while the superior (462.8 N, S.D. 237.2 N) and the mid-inferior portions (315.3 N, S.D. 181.5 N) were weaker. Similar trends across the tendon strips were shown for stiffness, ultimate stress and elastic modulus. RELEVANCE: Position dependent changes in mechanical properties of the infraspinatus tendon probably do not play a role in the pathomechanism of posterior shoulder dislocation. Peaks in stiffness in mid-superior and inferior tendon sections explain the low incidence of posterior dislocations. The low ultimate failure loads in the superior portions might explain the frequent extension of rotator cuff ruptures into the infraspinatus tendon.

Aged↗
PubMed1989

Rey-Auditory Verbal Learning and Rey-Osterrieth Complex Figure Design performance in Alzheimer's disease and closed head injury.

Performance on the Rey-Auditory Verbal Learning (R-AVL) and Rey-Osterrieth Complex Figure Design (R-O CFD) tests was examined in patients (N = 94) with dementia of the Alzheimer's type (DAT) and closed head injury (CHI). On the R-AVL, DAT patients demonstrated considerably greater impairment than CHI patients, along with a flat learning/retention curve that showed negligible improvement with repeated trials, recency effects only, and an excessive number of word intrusions (confabulation) on the recognition trial. CHI patients demonstrated both a recency and primacy effect along with improvement over repeated trials (positive slope learning curve). Both groups demonstrated impairment R-O CFD recall; the DAT group again displayed substantially greater copying and recall deficits. Clinical guidelines are given for the use of the R-AVL and R-O CFD for these two patient populations.

Adult↗
PubMed1986

Tissue distribution and myelotoxicity of daunomycin in the rat: rapid bolus injection vs continuous infusion.

The pharmacokinetic and cytotoxic behaviour of daunomycin in rats (7.5 mg/kg) when administered as an i.v. bolus injection were compared with those of a 3-hr infusion. After an i.v. bolus injection, the plasma drug levels decreased triphasically (t1/2 alpha = 0.8 min, t1/2 beta = 29.6 min and t1/2 gamma = 9.9 hr). The organs showed two types of concentration/time curves. One was found in the lungs, liver, kidneys and heart and had an initial high drug concentration followed by a relatively rapid elimination. The other was shown by the hemopoietic tissues (spleen and bone marrow): the drug uptake phase lasted longer (about 1.5 hr) and the elimination was slower. In general, daunomycin infusion led to substantially lower plasma and tissue levels, including in the heart, liver and kidneys. Again the hemopoietic tissues behaved in a different way: in spleen and bone marrow almost equal drug levels were obtained after daunomycin infusion as compared to a bolus injection. The myelotoxicity after daunomycin treatment was assessed by CFU-S (colony forming units-spleen) survival: the bolus injection killed as many CFU-S as did infusion (mean +/- S.D.: 11.8 +/- 5.3 CFU-S survival versus mean +/- S.D.: 13.5 +/- 2.4). Thus, it can be predicted that daunomycin infusion will lead to less cardiotoxicity but to an equal bone marrow suppression.

Animals↗
PubMed1986

Dietary characteristics of hyperactive and control boys.

The purpose of this study was to examine the relationship between dietary habits and behavioral problems in hyperactive boys and to determine how successful parents are in maintaining their children on sugar-free diets. The mothers of 32 hyperactive boys aged 7 to 12 years and 26 matched controls completed 3-day diet records and food frequency interviews. The hyperactive boys were also evaluated in a playroom for impulsivity, compliance, attention, motor activity, memory, and learning. No differences were found in any of the measures of dietary content between the hyperactive and control groups. The only significant differences between those two groups were a lower socioeconomic status and a greater number of parents attempting sugar-restricted diets in the hyperactive group. Boys on sugar-restricted diets had only one significant dietary difference from those not restricted. Correlations between the information obtained in food frequency interviews and in 3-day diet histories were not significant (r = .06 to .33) for the hyperactive group, but the food frequency interviews were significant for the control group (r = .41 to .47). Four behavioral variables showed significant partial correlations with reported sugar intake. Overall, the results demonstrated that the diets of a group of hyperactive boys were similar to those of a control group. There appeared to be little difference between the diets of the families that attempted to restrict sugar and those that did not.

Child↗
PubMed1985

Glycogen accumulation of the aging human brain.

We describe light- and electron-microscopically a new type of intracytoplasmatic inclusions within cell processes of the cerebral cortex and the underlying white matter. These structures measure 5-50 micron in diameter and consist almost exclusively of densely packed alpha- or beta-glycogen granules, which never occur together in any single structure. Within their periphery, electron-dense amorphous spots and cell organelles, especially mitochondria, were seen. No membrane-bound glycogen was observed. We propose to call them granular glycogen bodies. They occur in 4 of 7 examined postmortem specimens of the cerebral cortex of people older than 60 years of age. They were not found in 4 younger controls aged 26-48. Their appearance may reflect a distinct turnover disorder of carbohydrate metabolism, which becomes manifest under diverse pathologic conditions and in the normal aging process.

Adult↗
PubMed1985

Effects of sucrose ingestion on the behavior of hyperactive boys.

A challenge design was used in two separate studies to investigate the effects of sucrose ingestion on the behavior and learning of hyperactive boys. In both studies, 16 boys were admitted to a clinical research center for 3 successive days, on each of which they were given a sucrose-free diet. On day 1, baseline levels on the learning tasks were established; on days 2 and 3 a challenge drink of either sucrose 1.75 gm/kg or a placebo (aspartame in equivalent sweetness) was presented, in a counterbalanced order. In the first study the challenge drink was administered 1 hour after lunch; in the second study it was given in the morning after an overnight fast. On days 2 and 3 of both studies, 37 behavioral (playroom observation and examiner ratings) and cognitive (learning and memory tasks) measures were collected, starting 1/2 hour after ingestion of the drink. The results of both studies revealed no differences between the boys' performance on the two challenge days. These findings undermine the hypothesis that sucrose plays a major role in accounting for the inappropriate behavior of hyperactive boys.

Aspartame↗
PubMed1984

Repeated daunomycin administration in rats. Pharmacokinetics and bone marrow toxicity.

In the experiments described here, rats received three IV bolus injections (7.5 mg/kg) of daunomycin. The plasma data obtained after a single IV injection could be described by a two-compartment open model with t1/2 alpha and t1/2 beta values of 18.4 and 472.1 min. Of the tissues, the lungs contained the most daunomycin per gram of tissue, followed by the kidneys, liver, heart, and spleen. Daunomycinol was the main metabolic product and no substantial differences were found in daunomycinol content among the different organs. For all tissues and plasma, higher drug concentration values than would be expected on the basis of accumulation alone were observed after the second but not after the third injection. The cumulative urine excretion of daunomycin and daunomycinol remained essentially unchanged after one, two, and three daunomycin injections. However, the cumulative bile excretion increased after repeated daunomycin administration. The experiments in which the myelotoxicity was assessed by CFU-S survival after daunomycin treatment showed that three successive daunomycin administrations lead to a proportional reduction in stem cells.

Animals↗
PubMed1984

Evidence for a possible dose-dependent pharmacokinetics of Cyclosporin-A in the rat.

Cyclosporin-A (Cy-A) was administered to rats intravenously (i.v.) at different dosages (20, 40 and 80 mg/kg body weight). At the lower dose (20 mg/kg), the blood levels decreased biphasically and could be described by an open linear two-compartment model with excretion from the central compartment only. The t 1/2 values for the alpha-distribution and beta-elimination phases were about 6 min and 16.5 h, respectively. At higher dose levels (40 and 80 mg/kg), the involvement of an additional compartment became apparent. The blood concentration/time data sets obtained with 40 and 80 mg/kg doses were best described by an open linear three-compartment model. The 24-h urine and bile excretions were in the order of 10 and 20% of the total administered dose. The values for the normalized areas under the plasma concentration/time curves obtained at different Cy-A doses (20, 40 and 80 mg/kg) were about 1, 3 and 25, respectively.

Animals↗
PubMedDate not supplied

Study on cell survival, induction of apoptosis and micronucleus formation in SCL-II cells after exposure to the auger electron emitter (99m)Tc.

OBJECTIVE: To study the biological effectiveness of Auger electrons emitted by (99m)Tc on cell survival, induction of apoptosis and micronucleus (MN) formation in the human squamous cell carcinoma cell line SCL-II and compare the effects observed to those observed after exposure to external 60Co gamma radiation. MATERIAL AND METHODS: Cells were either gamma(60Co)-irradiated (0.67 Gy/min) or exposed to (99m)Tc-pertechnetate (0.95-14.3 MBq/ml) for 24 h under cell culture conditions and assayed for cell survival (colony-forming assay), micronucleus formation (cytochalasin B assay) and the frequency of apoptotic cells (fluorescence microscopy). Monte Carlo based dosimetry has been applied to derive the absorbed dose corresponding to the accumulated decays of (99m)Tc under the given geometry. RESULTS: Absorbed doses up to 0.5 Gy could be achieved after 99mTc-exposure leading to no substantial cell killing in this dose range except at one dose point (0.1 Gy) resulting in an relative biological effectiveness (RBE)SF 0.9 of 0.64 when compared to the 60Co reference radiation. MN formation was described best by a linear dose response and was consistently lower after 99mTc exposure when compared to 60Co irradiated cells resulting in an RBE of 0.37. Apoptosis induction was significantly increased after 99mTc exposure at much lower doses (0.1 Gy) when compared to the reference radiation. The (99m)Tc uptake experiments revealed an activity concentration ratio cells vs. medium of 0.07 after 24 h of exposure. CONCLUSION: No overall increased biological effectiveness due to the emitted Auger electrons of (99m)Tc, applied as sodium-pertechnetate, could be observed in the investigated cell line when compared to acute external gamma radiation. The RBEs in the range of 0.37-0.64 might be well explained by dose rate effects. The significantly increased apoptotic response after (99m)Tc-exposure at very low doses has to be further investigated.

Apoptosis↗
PubMedDate not supplied

[Psychological effect of corrective surgery in female patients with structural and functional abnormalities of the jaws].

20 young women (16 to 31 years of age) who underwent orthognatic surgery between 1979 and 1984 were subjected to an evaluation of their dental, orthognatic and psychological catamneses. The psychological results concerning operation motivation, preoperative stress and information, early postoperative condition and subjective assessment of the operative result are reported and discussed. Proposals are made to improve pre- and postoperative treatment of these patients.

Adolescent↗