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Biomedical subjects

B Roth

Publications and source records attributed to B Roth.

At least 163 records · Page 9Linked to original sources
PubMed1986

A study of optimal length of flexible fiberoptic sigmoidoscopes for initial endoscopic training.

Eighteen trainees with no prior fiberoptic endoscopic experience performed a total of 305 fiberoptic sigmoidoscopies using a colonoscope. Basic training, consisting of reading materials, lecture instructions, practice on a colon model, and observation of procedures, was completed prior to beginning patient examinations. Additional instruction was given between examinations. The performance of these examinations was an individual effort on the part of the trainee without verbal or mechanical assistance from the instructor after the initial ten examinations. All were performed with an instructor viewing through a teaching attachment. Total insertion distance was greater than or equal to 30, greater than or equal to 40, greater than or equal to 50, greater than or equal to 60 cm in 65, 60, 46, and 20 percent of examinations, respectively. Overall performance was better in those with prior rigid sigmoidoscopic experience (20 examinations). The mean examination time was 11.8 minutes. These data help to define the appropriate length of fiberoptic sigmoidoscope recommended for use by inexperienced endoscopists.

Education, Medical, Undergraduate↗
PubMed1986

[Treatment tactics and late results in early infection following osteosynthesis].

UNLABELLED: On the basis of long term results (five to 29 years), the treatment of postoperative wound infection after internal fixation (40 shaft fractures) is outlined. Of decisive importance is the immediate surgical intervention as soon as the first clinical signs of infection become evident. PROCEDURE: opening of the wound, leaving stable implants in situ, temporary irrigation drainage. RESULTS: in 31 cases spontaneous bone healing without bone grafting. Only in nine cases a residual infected focus needed cancellous bone grafting (in five of these cases additional surgical stabilisation, in the other four cases the bone itself was already sufficiently stable). In 35 patients full restoration of working capacity; in 33 patients full functional repair.

Combined Modality Therapy↗
PubMed1986

An EEG study of Wilson's disease. Findings in patients and heterozygous relatives.

The correlation of clinical and EEG findings was studied in 40 patients with Wilson's disease and their 57 heterozygous relations (25 children, 30 parents and 2 siblings). EEG changes in Wilson's disease were found in 84% (50% mild, 34% moderate) with but a slight predominance in patients with neurological involvement. The relatively high rate of pathological EEG findings in the hepatic or asymptomatic forms suggested the presence of subclinical CNS damage even in these cases. Diffuse episodic abnormalities were a dominant feature in all the groups under observation. As for the heterozygous relatives, a significant increase in pathological EEG findings (80-28% mild, 52% moderate to severe) was found in the heterozygous children. The changes often correlated with the clinical detection of minimal brain damage. The grossest EEG changes were seen in the youngest age group (under 10 years of age) with a subsequent tendency to abatement. In 2 cases there was an extinction of specific epileptic graphoelements which may have been the result of long-term penicillamine administration. In the adult heterozygous population (parents and siblings) there was no significant increase in the rate of pathological EEG findings compared with our control group. The authors discuss the problem of control mechanisms which have a role to play in the normalization of biochemical and probably also clinical and EEG findings in the heterozygotes.

Adult↗
PubMed1986

Nifedipine in hypertensive crises of infants and children.

Nifedipine given by the sublingual route has been used in the treatment of 30 hypertensive emergencies in 20 children suffering from renal disease. The mean dosage of nifedipine was 0.33 mg/kg body weight. In 20 hypertensive crises occurring in 16 patients a single dose of nifedipine was sufficient to lower systolic as well as diastolic blood pressure significantly within 90 min. for a period of 4 to 12 hours. No side effects were noted with the exception of a transient flush in one patient. Nifedipine proved to be suitable for the primary treatment of hypertensive emergencies in children suffering from renal hypertension. The advantages of nifedipine compared to other drugs used for treating hypertensive crises is the rapid onset of the antihypertensive action without need for an intravenous form of administration.

Adolescent↗
PubMed1986

Activation of EEG recordings by graded sleep deprivation.

Part I. The EEG recordings of 434 patients were activated by graded sleep deprivation. In clinically manifest epilepsies with a predominantly negative EEG tracing at rest the incidence of epileptic manifestations increased after sleep deprivation from 18.03% to 59.01%, in clinically suspect epilepsies from 6.4% to 39.0%. In other paroxysmal affections such as febrile convulsions, syncopes and collapses, paroxysms of abdominal pain or headaches, affective paroxysms and nocturnal terrors, the tracing activation by sleep deprivation mostly facilitated differential diagnosis between those affections and epilepsy. In organic cerebral affections with or without epileptic seizures activation by sleep deprivation led to an increase in the occurrence of epileptic manifestations from 11.4% to 50.0% of the recordings. The authors conclude that graded sleep deprivation is a very useful activation method for the diagnosis of epilepsy. Part II. The authors studied the occurrence of generalized 2-5 Hz high-amplitude slow wave episodes in 244 patients before and after sleep deprivation. They found such episodes in the resting recordings of 37 patients and in the post-deprivation recordings of 85 patients. The described episodes were mostly observed during sleepiness and superficial sleep. They were significantly more frequent in children and adolescents than in adults. The occurrence of slow wave episodes was ascertained in epileptic as well as non-epileptic affections such as affective attacks in children, night terrors, paroxysms of abdominal pain or headaches, febrile convulsions and organic brain affections without epileptic seizures. The authors conclude that the above episodes are a non-specific manifestation of increased susceptibility to paroxysmal synchronization of EEG rhythms. Their occurrence in young children can, however, be considered normal.

Adolescent↗
PubMed1986

Design of dihydrofolate reductase inhibitors from X-ray crystal structures.

Dihydrofolate reductase (DHFR) is an important therapeutic target for treatment of cancer and microbial disease. Its species specificity has resulted in the sequencing of a number of vertebrate and bacterial DHFRs, and the three-dimensional structure of isozymes from Escherichia coli, Lactobacillus casei, and chicken liver has been elucidated, in the presence of the coenzyme NADPH and of a number of inhibitors. This information has enabled scientists to try to design improved and more selective inhibitors, based on the known coordinates of the enzyme features. Simple use of computer graphics or wire models has resulted in the design of inhibitors with 50 times the activity of trimethoprim, an antibacterial DHFR inhibitor, by making use of an unused ionic binding site. However, in a number of instances this approach was completely unsuccessful because hydrophobic sites of interaction were preferred. More sophisticated techniques involve energy minimization of the small molecule-macromolecule interactions to optimize the geometry. In this paper I describe the use of a molecular mechanics program, AMBER, for predicting the geometry and relative energetics of binding. Very encouraging results have been obtained for a closely related series of compounds. Where differing entropic and solvent effects are involved, predictions may be poor. The use of super computers and molecular dynamics methods should increase this capability in the near future.

Binding Sites↗
PubMed1986

An alternative to the multiple sleep latency test for determining sleepiness in narcolepsy and hypersomnia: polygraphic score of sleepiness.

This article describes a quantitative assessment of pathological diurnal sleepiness in three groups of patients with excessive daytime sleepiness: narcoleptic patients, idiopathic hypersomniac patients, hypersomniac patients with sleep apnea syndrome. We analyzed polygraphic diurnal recordings of 45 min duration obtained under standardized conditions. We called the percentage of total sleep time during the 45-min recording the polygraphic index of sleepiness. The polygraphic score of sleepiness is determined by the latencies and total durations of the individual sleep stages. Because deeper sleep stages correspond to more pronounced sleepiness than do superficial sleep stages, we introduced coefficients for each sleep stage. We present a formula for calculating a score in a single figure that gives a good indication of the patient's sleepiness and makes inter- and intraindividual comparison possible. Separate REM and NREM sleep scores are also given.

Disorders of Excessive Somnolence↗
PubMed1985

Receptor-based design of dihydrofolate reductase inhibitors: comparison of crystallographically determined enzyme binding with enzyme affinity in a series of carboxy-substituted trimethoprim analogues.

By the use of molecular models of Escherichia coli dihydrofolate reductase (DHFR), analogues of trimethoprim (TMP) were designed which incorporated various 3'-carboxyalkoxy moieties in order to acquire ionic interactions with positively charged active-site residues. Certain of these compounds have shown exceptionally high affinity for this enzyme. For example, the 3'-(carboxypentyl)oxy analogue was found to be 55-fold more inhibitory than TMP toward E. coli DHFR (Ki = 0.024 nM vs. 1.32 nM for TMP). X-ray crystallographic studies of E. coli DHFR in binary complexes with TMP and two members of this acid-containing series of compounds defined the binding of these inhibitors and showed the carboxyl group of the latter two inhibitors to be ionically bound to Arg-57. These observations were in agreement with postulated binding modes that were based on receptor modeling.

Binding Sites↗