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Biomedical subjects

B Conrad

Publications and source records attributed to B Conrad.

At least 199 records · Page 11Linked to original sources
PubMed1983

Flight, flight duty, and rest times: a comparison between the regulations of different countries.

Flight time, flight duty limitations, and rest requirements are compared between the regulations from nine different countries. Twelve factors are identified which played a role in formulating restrictions and criteria. Duration of flight duty and crew augmentation are the factors considered by most countries; time of day, night flight, night sleep, and time zones are the factors least considered. Conformity exists in the necessity to prescribe maximum permissible flight or duty times and minimum rest requirements on a daily basis. Agreement was also observed in grading the standards according to more or less fatiguing conditions. Six out of nine regulations define night hours, but fail to agree upon beginning, end, and duration of night. All countries but one limit flying hours on a monthly and yearly basis, although the limits diverge. A brief outline of the German provisions is presented as an example for a compact and practicable regulation.

Australia↗
PubMed1983

A model for prediction of resynchronization after time-zone flights.

Utilizing experimental data from three flight studies, a concept was developed which allows appraising average resynchronization for any day after arrival in a new time-zone. The course of adaptation is nonlinear and can be mathematically represented by an exponential function. The model predicts higher initial resynchronization rates when more time zones are crossed, but total time for complete reentrainment is essentially the same and, thus is independent of the number of time-zones. The equation derived from experimental data is converted into an e-function and the resulting time constants are presented as they evolved for different functions and flight directions.

Aerospace Medicine↗
PubMed1982

Microcomputer programs for DNA sequence analysis.

Computer programs are described which allow (a) analysis of DNA sequences to be performed on a laboratory microcomputer or (b) transfer of DNA sequences between a laboratory microcomputer and another computer system, such as a DNA library. The sequence analysis programs are interactive, do not require prior experience with computers and in many other respects resemble programs which have been written for larger computer systems (1-7). The user enters sequence data into a text file, accesses this file with the programs, and is then able to (a) search for restriction enzyme sites or other specified sequences, (b) translate in one or more reading frames in one or both directions in order to find open reading frames, or (c) determine codon usage in the sequence in one or more given reading frames. The results are given in table format and a restriction map is generated. The modem program permits collection of large amounts of data from a sequence library into a permanent file on the microcomputer disc system, or transfer of laboratory data in the reverse direction to a remote computer system.

Base Sequence↗
PubMed1982

[Lesions of the peripheral nervous system in the treatment of breast cancer].

On the basis of our own patients, the anamnestic data and the neurological constellation in late radiogenic paresis (the most frequent peripheral nervous condition in treatment of mammary carcinoma) are described. A comparison with the situation in metastatic infiltration of the brachial plexus shows the great difficulties in differential diagnosis. Pain can be observed more frequently in metastatic plexus infiltration. The presence of a Horner syndrome can be regarded as decisive evidence for recurrent growth of a carcinoma. If a Horner syndrome is absent, tumor growth can be demonstrated conclusively only by biopsy or surgical exploration. The most frequent condition which is not connected with mammary carcinoma and its followup treatment, but which can stimulate a late radiogenic paresis of the brachial plexus is the carpal tunnel syndrome. Whereas a certain differentiation is not always possible on the basis of the anamnesis and clinical findings, a clear discrimination is possible by means of electrophysiological investigation techniques.

Brachial Plexus↗
PubMed1980

The value of electrophysiological examination of the flexor carpi ulnaris muscle in the diagnosis of ulnar nerve lesions at the elbow.

The aim of the present study was to answer the question whether electrophysiological examination of the m.flexor carpi ulnaris, especially of the distal latency (stimulation point 2 cm above the sulcus ulnaris) to this muscle, represents a valid procedure for the localisation of an ulnar nerve lesion at the elbow. In 64 patients, a total of 68 ulnar nerve lesions at the elbow were subjected to conventional clinical and electrophysiological examinations. A pathologically prolonged distal latency to m.flexor carpi ulnaris (> 4.0 ms) was found in 82.4% of the patients. In terms of their value in the topo-diagnosis of an ulnar lesion, measurement of the distal latency to m.flexor carpi ulnaris and conventional analysis of trans-sulcal motor conduction velocity of the fibres to the hypothenar muscles yield equivalent information. However, evaluation of the distal latency to m.flexor carpi ulnaris is not only subject to fewer sources of error but is also technically much easier to perform. In the localisation of a clinically suspected ulnar nerve lesion at the elbow, we therefore suggest that the electrophysiological investigation should commence with an examination of the distal latency to m.flexor carpi ulnaris.

Adolescent↗
PubMed1980

The distal sensory nerve action potential as a diagnostic tool for the differentiation of lesions in dorsal roots and peripheral nerves.

On the basis of the conception that, in preganglionic lesions, peripheral sensory nerve fibers should remain intact, the question arises whether evaluation of distal sensory nerve action potentials can be helpful in differentiating between cervical dorsal root and peripheral nerve lesions. Amplitudes of sensory nerve action potentials (SNAP) and corresponding distal sensory conduction velocities (SCV) of the median and ulnar nerves were measured in 194 patients with distal sensory impairment and in 20 control subjects. In dorsal root lesions attributable to degenerative changes of cervical spines and/or discs, SNAP and SCV were within the normal range. In peripheral nerve lesions, located in the brachial plexus, or at the elbow or wrist, diminished SNAP amplitudes and/or slowing of SCV were found. It is concluded that in patients with sensory deficit in the hands recordings of SNAP make a differentiation between lesions of dorsal roots and peripheral nerves possible.

Action Potentials↗
PubMed1979

High cervical neurinoma (C1/C2) diagnosed falsely as multiple sclerosis because of trigeminal neuralgia.

Remitting paresis of the left leg accompanied by left trigeminal neuralgia led to the diagnosis of multiple sclerosis in a 46-year-old woman. Over the following 6 years, an incomplete syndrome of the spinal cord developed along with bilateral trigeminal pain. Neuroradiological and neurosurgical exploration a neurinoma located ventrolaterally at C1/C2 on the left side. It is emphasized that since trigeminal fibres descend as far as the upper part of the C2 segment, trigeminal neuralgia should not be considered as an exclusively supraspinal symptom.

Cerebral Palsy↗
PubMed1979

Speech and respiration.

This investigation deals with the temporal aspects of air volume changes during speech. Speech respiration differs fundamentally from resting respiration. In resting respiration the duration and velocity of inspiration (air flow or lung volume change) are in a range similar to that of expiration. In speech respiration the duration of inspiration decreases and its velocity increases; conversely, the duration of expiration increases and the volume of air flow decreases dramatically. The following questions arise: are these two respiration types different entities, or do they represent the end points of a continuum from resting to speech respiration? How does articulation without the generation of speech sound affect breathing? Does (verbalized?) thinking without articulation or speech modify the breathing pattern? The main test battery included four tasks (spontaneous speech, reading, serial speech, arithmetic) performed under three conditions (speaking aloud, articulating subvocally, quiet performance by tryping to exclusively 'think' the tasks). Respiratory movements were measured with a chest pneumograph and evaluated in comparison with a phonogram and the identified spoken text. For quiet performance the resulting respiratory time ratio (relation of duration of inspiration versus expiration) showed a gradual shift in the direction of speech respiration--the least for reading, the most for arithmetic. This change was even more apparent for the subvocal tasks. It is concluded that (a) there is a gradual automatic change from resting to speech respiration and (b) the degree of internal verbalization (activation of motor speech areas) defines the degree of activation of the speech respiratory pattern.

Adult↗
PubMed1979

Electromyographic examination of gluteal muscles in the differential diagnosis of lumbar herniated discs.

The aim of the present investigation was to establish the value of gluteal muscles (m.gluteus medius, GME; m.gluteus maximus, GMX) as segmental reference muscles in the topical diagnosis of lumbar root compression syndromes. The methodological rationale consisted in determining the frequency with which denervation potentials could be recorded in the GME and GMX of patients with clinically and electromyographically well-defined monosegmental or bisegmental lumbar root compression syndromes. Of the L5-syndromes (N=36), 81% revealed denervation potentials in GME, but only 6% in GMX. Of the S1 syndromes (N=26), 63% exhibited denervation potentials in GMX and 32% in GME. L5 syndromes showed a better correlation of positive findings to GME than S1 syndromes to GMX. As far as the differential diagnosis is concerned, the advantages of recording EMG from GME and GMX are two-fold: (a) the immediate certainty of excluding a peripheral nerve lesion and (b) a reduction in the incidence of false negative findings.

Adult↗
PubMed1979

Comparative study of the aerobic, heterotrophic bacterial flora of Chesapeake Bay and Tokyo Bay.

A comparative study of the bacterial flora of the water of Chesapeake Bay and Tokyo Bay was undertaken to assess similarities and differences between the autochthonous flora of the two geographical sites and to test the hypothesis that, given similarities in environmental parameters, similar bacterial populations will be found, despite extreme geographic distance between locations. A total of 195 aerobic, heterotrophic bacterial strains isolated from Chesapeake Bay and Tokyo Bay water were examined for 115 biochemical, cultural, morphological, nutritional, and physiological characters. The data were analyzed by the methods of numerical taxonomy. From sorted similarity matrices, 77% of the isolates could be grouped into 30 phena and presumptively identified as Acinetobacter-Moraxella, Caulobacter, coryneforms, Pseudomonas, and Vibrio spp. Vibrio and Acinetobacter species were found to be common in the estuarine waters of Chesapeake Bay, whereas Acinetobacter-Moraxella and Caulobacter predominated in Tokyo Bay waters, at the sites sampled in the study.

Aerobiosis↗
PubMed1978

Hereditary bimanual synkinesis combined with hypogonadotropic hypogonadism and anosmia in four brothers.

A new genetic syndrome of the combined occurrence of hypogonadotropic hypogonadism, anosmia (Kallmann syndrome) and congenital mirror movements in four brothers is presented. Mirror movements were manifest only within the distal parts of the upper extremities and resembled congenital mirror movements described for isolated or familial cases or those occurring in combination with other genetic defects. The hypothesis is supported, that a midline fusion disorder with preponderance of uncrossed pyramidal tract fibers is a major pathogenetic factor for the occurrence of congenital mirror movements.

Adult↗