Biomedical subjects

E Schuhmann

Publications and source records attributed to E Schuhmann.

At least 19 recordsLinked to original sources

PubMed1998

Diagnostic utility of two commonly used ADHD screening measures among special education students.

OBJECTIVE: To examine the diagnostic utility of two commonly used attention-deficit hyperactivity disorder (ADHD) screening measures in a population of special education students and address whether screener performance is affected by demographic characteristics. METHOD: A school district population of special education students was screened for ADHD risk using two parent questionnaires, the 46-item Attention Deficit Disorders Evaluation Scale (ADDES) and the 10-item Conners Abbreviated Symptom Questionnaire (ASQ). All high-risk children and a random sample of low-risk children subsequently underwent DSM-IV-based diagnostic assessment through parental diagnostic interviews (Diagnostic Interview Schedule for Children Version 3.0). Diagnostic utility was summarized by sensitivity, specificity, predictive utilities of positive and negative tests, and efficiency, all of which were estimated using an approach that accounted for the sampling design. RESULTS: Overall efficiency scores ranged between 70% and 74%. Sensitivity estimates were below 70% even at low screener cutoff scores. The ADDES did not perform significantly better than the ASQ. Significant gender and ethnicity effects emerged. CONCLUSIONS: Overall, both the ASQ and the ADDES yielded substantial numbers of false positives and false negatives among this population of children, indicating that alternative approaches will be required to accurately and efficiently identify children in need of services for ADHD. Child psychiatrists can play a valuable consulting role as school districts and primary care settings struggle to implement appropriate identification procedures for ADHD.

Attention Deficit Disorder with Hyperactivity↗

PubMed1996

Cognitive gender differences in very young children parallel biologically based cognitive gender differences in monkeys.

Infant humans were trained on 2 cognitive tests that have previously revealed, in infant monkeys, a double dissociation that was reversible by perinatal manipulations of androgens and ablations of specific brain sites. Children showed the same sex-linked behavior found with infant monkeys: young boys were superior on the object reversal task and young girls were superior on the concurrent discrimination task. As happened previously with infant monkeys, the gender difference was not apparent in older human subjects. Thus, early in ontogeny, cognitive gender differences have now been discovered in both humans and monkeys, probably a result of gender differences in androgens that influence the maturation rate of specific brain systems.

Adolescent↗

PubMed1989

[Hemodynamic effects of the new phosphodiesterase inhibitor enoximone in heart surgery patients].

The new phosphodiesterase-III inhibitor (PDI) enoximone is a non-catecholamine, non-glycoside cardiotonic agent with concomitant vasodilating properties. It has proved beneficial in patients with severe chronic heart failure. The influence of enoximone i.v. on hemodynamics was investigated during cardiac surgery under various conditions. METHODS. A randomized series of 60 patients undergoing elective aorto-coronary bypass grafting were studied. The hemodynamic effects of 0.5 mg/kg enoximone given i.v. as a bolus (30 s) were investigated before anesthesia (n = 10), during anesthesia (n = 10), and during extracorporeal circulation (ECC, n = 10) and compared with those observed in corresponding control groups (n = 10 in each control) of patients who had received saline solution as placebo. Anesthesia was maintained with weight-dependent dosages of fentanyl, midazolam and pancuronium bromide. All patients were invasively monitored by means of a pulmonary artery catheter. Additionally, left ventricular pressure (LVP), left ventricular end-diastolic pressure (LVEDP) and dp/dtmax were measured before the initiation of ECC. During ECC direct vascular effects were investigated with measurement of perfusion pressure and the volume of the oxygenator. RESULTS. Before the induction of anesthesia no significant change in MAP and HR could be observed, whereas CI increased (+20%) and TSR decreased (-24%) significantly. During anesthesia, the injection of enoximone was followed by a significant decrease in MAP only in the 1st min (-17%); baseline level was reached again after 6 min; and HR was slightly increased (+8%). TSR (-31%) and LVEDP (-38%) decreased, whereas CI (+17%) and dp/dtmax (+45%) were increased significantly. During ECC perfusion pressure (-37%) and the volume of the oxygenator (-17%) were significantly decreased, demonstrating direct vasodilating effects on both the arteries and the vein. CONCLUSION. Arterial and venous vasodilation with an increase in myocardial performance (dp/dtmax) resulting in an increase in CI were the predominant hemodynamic effects of enoximone i.v. No arrhythmogenic effects or interactions with the anesthetics used were observed in this study.

Anesthesia↗

PubMed1989

[Effect of a single mild infrared A hyperthermia on body temperature, heart rate, blood pressure and blood viscosity in healthy probands and patients with stage I and II arterial hypertension].

Report on mild and single whole body-irradiations with near infrared (IRA). The central body temperature went up to 38.5 degrees C in 9 healthy subjects and 9 patients known as having essential arterial hypertension of the stages I or II. In case of hypertensive patients a single exposure decreased significantly both arterial and venous blood pressure as well as the resulting mean arterial blood pressure. This beneficial effect lasted for at least 24 hours. Besides that, improvement of peripheral hemodynamics and plasma viscosity also was proven. Obviously, improved peripheral hemodynamics is linked to that blood pressure lowering effect which happens due to dilatation of peripheral blood vessels.

Adult↗

PubMed1988

[Enoximone, a new phosphodiesterase inhibitor: the spectrum of applications during heart surgery--a comparison with dobutamine].

During cardiac surgery treatment of deterioration of myocardial function is usually based on catecholamines. Development of selective phosphodiesterase-(PDE-)III-inhibitors seems to be a new aspect in treating myocardial dysfunction. Therefore the hemodynamic effects of the new PDE-inhibitor enoximone were investigated in 20 coronary surgery patients unable to be weaned from extracorporeal circulation (ECC) without pharmacological intervention (MAP less than 60 mmHg, CI less than 2.00 l/min.m2, PCP greater than 15 mmHg). After controlled reperfusion with 2.4 1/min.m2 two groups were separated in a random sequence receiving either 0.5 mg/kg enoximone as a bolus (n = 10), or dobutamine (n = 10, 5 micrograms/kg.min) as perfusion. In the dobutamine-group MAP and CI (-14%) were decreased, while HR was increased significantly (+30%). Application of enoximone was followed by a slight increase in CI (+5%), a significant decrease in TSR while HR remained almost unchanged. PCP, too, differed significantly between the groups (enoximone: -38%; dobutamine: -10%). Ten minutes after weaning from ECC additional pharmacologic therapy (calcium, vasodilators, epinephrine) was necessary in eight dobutamine treated patients in contrast to four patients in the enoximone group (calcium, epinephrine). In patients with impaired myocardial performance during weaning from ECC enoximone seems to be an alternative therapy and is judged to be of some advantage compared to dobutamine application in this situation. The mechanism for improvement appears to be enhanced contractility owing to its positive inotropic effects, as well as a decrease in left ventricular outflow resistance resulting from peripheral vasodilation.

Aged↗

PubMed1986

[Laboratory experiment studies on quantitative blood flow measurement with the continuous-wave ultrasound Doppler procedure: I. Transducer evaluation].

Cw-Doppler transducers designed for volume blood flow measurement were evaluated experimentally. Both sensitivity plotting using a ball point reflector and comparative volume flow measurement on a flow-rig using EMF as reference method evidenced unequal sensitivity along the transducer. With increasing distance to the transducer the longer axis of the oval sound field assumed an orientation perpendicular to the longer axis of the active transducer surface. Sensitivity decreased from the centre of the sound field to its periphery. Differences of more than 2 mm between the length of the transducer and the diameter of the latex tube resulted in over- or underestimations of volume flow. Underestimations found with transducers longer than the tube diameter were interpreted as resulting from the increased contribution of stable echoes to the signal.

Blood Flow Velocity↗

PubMed1985

Studies of colicin action on wall-less stable L-forms of Escherichia coli. II. Growth inhibition of complete and wall-less (L-form) cells of Escherichia coli by basic colicin types.

The inhibitive activity of colicins of 16 types (produced by 22 colicinogenic strains) on rods and protoplast-like stable L-form cells of the strains Escherichia coli B, W1655 F+ and W1655 F- was compared. The results of 58 combinations tested fall into four groups (with three subgroups): both cell forms are sensitive: a) both cell forms are about equally sensitive, b) rods are distinctly more sensitive than L-form cells, c) L-form cells are distinctly more sensitive than rods; only rods are sensitive, L-form cells are not sensitive; only L-form cells are sensitive, rods are not sensitive; neither cell form is sensitive. Group la represents simple sensitivity; both cell wall and cytoplasmic membrane receptors are present and functioning. Groups 1b and 2 represent sensitivity, substantially or completely mediated by cell wall receptors. Groups 1c and 3 represent partial or complete "pseudoresistance" or "pseudotolerance"; cell wall receptors are absent or non-lethal, but cytoplasmic membrane ones are present and mediate the lethal effect. Group 4 represents both true resistance and true tolerance.

Colicins↗

PubMed1985

Studies of colicin action on wall-less stable L-forms of Escherichia coli. III. A colicin-tolerant mutant in a wall-less stable L-form.

The conversion of a tol III Escherichia coli mutant, tolerant to colicins E2, E3, Ia and K, into protoplast-like stable L-form makes it sensitive to colicins E2, Ia and K. Its original sensitivity to colicin E1 and tolerance to E3 are preserved in this cell form. Thus, rods of this mutant are not truly tolerant to colicins E2, Ia and K, but "pseudotolerant": their wall receptors have been turned out to "nonlethal" ones by the mutation in question.

Colicins↗

PubMed1979

Studies of colicin action on wall-less stable L-forms of Escherichia coli. I. Degree of attachment and of killing effect on rods and stable L-form cells.

Escherichia coli strains B and K12 W 1655 F+ are able to bind more lethal units of colicins E2, E3, G, H, Ia, and K+ X per one stable L-form cell (of the protoplast type) than per one rod cell; colicin D is bound in a higher amount on E. coli B rods. This pattern remains unchanged, if the same colicins are attached on chloroform-killed cells of both forms. Rods of both E. coli strains are more sensitive to colicins D, E2, E3, K + X (as--in the strain B--to colicin Ia) than cells of the respective L-forms. In the strain W 1655 F+ both cell forms are equally highly sensitive to colicin Ia. The stable L-forms of both strains are much more sensitive to colicins G and H than the rods. Thus the Gram-negative cell wall decreases the probability of a colicin molecule to get attached to its receptor in the cytoplasmic membrane. On the other hand, in E. coli cells the attachment of most colicin molecules to the wall receptors increases the probability of their biological effect. There is no such effect of the wall-attachment on the action of colicins G or H. The strain B is tolerant to colicin E2, while being resistant to E3; thus the cytoplasmic membrane receptor sites for them are not identical.

Adsorption↗

PubMed1977

[Effect of Cu++ ions on the morphological, cytological, and physiological state of Candida utilis cells in continuous culture].

Cells of Candida utilis grown in continuous culture under the influence of rather high concentrations of copper ions have been studied biochemically, morphologically, and cytologically. Although under these conditions a new steady state has been adjusted, the population is much more differentiated than under control conditions. With regard to their size, structure, and viability the cells have been arranged into 4 groups. Generally, the "copper cells" in comparison with the "normal cells" are more voluminous (average: 2.5 times; maximum: 4 times) and of altered structure. The appearance of dense particles ("copper containing particles"), globules ("lipid globules"), vacuoles, and the thickening of the cell wall, as well as the disappearance of the mitochondrial cristae have been shown as characteristic indications for damage in the cell substructure caused by the influence of copper ions. Occasionally abnormal cell shapes can be observed. A permanent influence of copper ions in the concentration used was followed also by striking disturbances of the cell metabolism. The cells take up more carbon, phosphorus, and nitrogen, whereas protein synthesis and respiratory activity decrease. Both the synthesis of lipids and polysaccharides and the phosphohydrolase activity increase. A discussion of the experimental data is presented.

Candida↗

PubMed1976

[Microscopic studies of Streptomyces hygroscopicus growth kinetics].

Growth kinetics, branch formation, and cytological properties of mycelial growth of Streptomyces hygroscopicus on solid media were investigated by phase-contrast microscopy using a microculture method. Measurements were made on taken photographs of the growing hyphae from the beginning of spore germination up to maximal 18 hours. The specific growth rate of the germ tube was much higher than the specific growth rate of the mycelium. The doubling time of the total length of the mycelial hyphae and the doubling time of branch formation was quite the same for the period investigated. After a short time of outgrowth each individual hypha grows at a constant rate, i.e. the length increases linearly, but the growth kinetics of the whole mycelium becomes exponentially by branching. It seems, that nucleoids only divide in that part of a hypha between the tip and the nearest branch. A cell unit (1.4-1.9 mum on different media) could be calculated by the length of a hypha and the number of nucleoids. A hypha is growing with the cell unit at the tip or with the polar cap only. No interkalary growth in length could be found. Branches were formed only up to about 100 mum from the tip on complex medium and up to about 50 mum from the tip on mineral salt medium. A simple method of mycelial growth has been developed. Some properties showing the connection between Streptomycetes and prokaryotic organisms on one hand and hyphal growing fungi on the other hand are discussed.

Culture Media↗

PubMed1976

Effects of polyene macrolide antibiotics on normal and protoplast type L-form cells of Escherichia coli W1655F+.

The action of the polyene macrolide antibiotics mycotrienin, pimaricin, lucensomycin, tetramycin, rimocidin, nystatin, filipin, lagosin, pentaene antibiotic 2814P, flavomycoin, flavofungin, hexaene antibiotic 5001P, and candicidin, including perhydro derivatives of them, on wall-less stable protoplast type L-form and normal rod form cells of E. coli W1655F+ was studied. No inhibition of the normal rod form cells was detected. In contrast to these results the growth of the L-form cells was inhibited by all of the substances tested, with the exception of pimaricin. Further experiments have shown that the differences in sensitivity of normal and L-form cells cannot be explained by differences in sterol content, the target site of polyene antibiotics in sensitive eukaryotic cells. According to our results it is obvious that the cell wall of the normal cells functions as a penetration barrier to polyene antibiotics.

Anti-Bacterial Agents↗

PubMed1975

[Effect of polyene macrolide antibiotics on normal and cell wall deficient Escherichia coli W1655F+ cells].

The polyene macrolide antibiotics are active against yeast, fungi, and other eukaryotic cells, but are with a few exceptions inactive against bacteria. The resistance of bacteria against these compounds is usually explained by the absence of sterols in their cells, the target sites of polyene antibiotics. However, in our experiments with mycotrienin, nystatin, tetramycin, lucenosmycin, rimocidin, filipin, lagosin, flavofungin, flavomycoin, antibiotic 2814P, antibiotic 5001P, and candicidin it was demonstrated that bacteria may be susceptible to polyene antibiotics, too, if the wall-less stable protoplast type L-form of E. coli W1655F+ is used. The measured growth inhibition concentrations were comparable with those of typical antibacterial antibiotics. Our experiments have shown that the normal rod form and the wall-less L-form of E. coli W1655F+ contain traces of sterols in nearly the same concentration range. This means that the selective sensitivity of the L-form cannot be explained by higher sterol content of these cells in comparison to the resistant normal rod form cells. We assume that the bacterial cell wall is responsible for the resistance of the normal rod form by masking internal target sites.

Anti-Bacterial Agents↗

PubMed1974