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Biomedical subjects

J G Thomas

Publications and source records attributed to J G Thomas.

At least 37 records · Page 2Linked to original sources
PubMed1992

Grip strength as a function of 200 repetitive trials.

A study was done to see how grip strength deteriorates after an extended number of grips. Eight male subjects, all right-handed and 23 to 35 years old, participated. Each subject made 200 grips on a dynamometer at his maximum strength. There were 15-sec. rests between trials. Performance dropped significantly after two trials. There were drops of about 40% and 50% at Trials 100 and 200, respectively. The grip strength/trial relationship is logarithmic as noted by Montazer and Thomas in 1991.

Adult↗
PubMed1991

Grip strength as a function of repetitive trials.

An experiment on repetitive hand-gripping tasks was conducted to determine the functional relationship between the maximum grip strength and number of trials. Nine male subjects performed 30 gripping trials at their maximum strengths with 15-sec. rests between trials. Performance dropped significantly after two trials. Over-all, there was a 30% drop in maximum grip strength after 30 trials. The decrease in strength over trials is described by a logarithmic function.

Adult↗
PubMed1991

Automatic measurements of fetal long bones. A feasibility study.

We investigated whether it would be possible for a computer to propose values for measurements commonly obtained (femur and humerus) during obstetrical sonography. In this preliminary study, the images were scanned and analyzed off-line using morphological operators. The procedure described allowed us to measure the long bones and has a very high coefficient of correlation with measurements obtained by humans. Ideally, the whole procedure could probably be part of the computer instructions that are built into the machine.

Algorithms↗
PubMed1987

Oxfendazole pulse release intraruminal devices and bovine parasitic bronchitis: comparison of two control strategies in a field experiment.

Lungworm-infected seeder calves were used on two 1.41 ha paddocks to ensure that groups of 11 susceptible trial calves would be exposed to heavy early season challenge with Dictyocaulus viviparus. This produced conditions for an artificially severe test of two control strategies. The first employed a front-loaded oxfendazole pulse release bolus, ie, an intraruminal device which released one therapeutic anthelmintic dose immediately and five subsequent pulses at approximately three-weekly intervals. These front-loaded boluses were given to five of 11 calves on one paddock as soon as parasitic bronchitis had become clinically obvious (34 days after turnout) while the remaining six calves were kept as untreated controls. Clinical signs quickly subsided in the treated animals and no further respiratory problems occurred despite continued exposure to reinfection. The other control strategy involved the administration at turnout of an oxfendazole pulse release device which released the first of five anthelmintic doses approximately three weeks after administration, to all 11 calves on the other paddock. This strategy was almost completely successful in preventing patent infections from establishing and reduced the infectivity of the pasture in August and September by 94.1 per cent as shown by tracer calf studies. The calves treated at turnout performed better than the calves treated with the front-loaded boluses for most of the season and had an average weight-gain advantage of 20.4 kg at housing (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Spontaneous changes in the morphology of the human short-latency somatosensory evoked response: an interpretation in terms of two superimposed waveform components.

Spontaneous changes, with a time scale of hours or sometimes days, in the morphology of the short-latency somatosensory evoked response in comatose head injury patients were analyzed by a computer processing based on the proposition that the early cortical response consists of a superposition of two waveform complexes. These complexes were deduced to have similar triphasic forms, but one of them was delayed. The amplitude fluctuations of this delayed component caused the changes in the morphology of the response.

Brain Injuries↗
PubMed1986

Computer generation of templates for evaluating the amplitude and latency parameters of two superimposed constituent components of early somatosensory evoked responses.

From a study of the range of morphologies of the early somatosensory evoked response (SSER) to median nerve stimulation in a large number of neurosurgical patients, the earliest cortical SSER has been inferred to consist of two superimposed waveform complexes. A description is given of the process of generating templates in the computer so that the relative amplitudes and latencies of these two complexes can be determined by inspection. It is suggested that although the neural substrate of the two complexes is at present unknown, their evaluation in responses will provide additional information which will be useful when using SSERs as aids to the diagnosis of neurological disease.

Brain Injuries↗
PubMed1986

Computer implemented digital filtering, scaling and addition for analysing the structure of early somatosensory evoked responses.

Computer-implemented digital filters are used to separate the fast wave complexes which are superimposed on slower background waves in human short latency somatosensory evoked responses (SSERs). The choice of filter for picking out the fine structure of the fast wave is shown to be not critical. After scaling and adding digitally filtered SSERs from two electrode montages, the peaks believed to be of cortical origin are cancelled, leaving visible a repetitive wave which must be presumed to be generated subcortically. From this, a new interpretation of the origins of peaks in short latency SSERs is made.

Adolescent↗
PubMed1986

Multicenter clinical trial and laboratory utilization of an enzymatic detection method for gonococcal antigens.

Seven institutions participated in a comparative study evaluating standard culture method and a new enzyme immunoassay (EIA, Gonozyme, Abbott Diagnostics) for the detection of Neisseria gonorrhoeae. Five hundred twenty-three patients were entered from hospitals of various sizes representing different population densities, ethnic and economic sectors, and gonococcal prevalence. Statistical analysis showed sensitivity, specificity, and positive and negative predictive values of 80.3%, 94.6%, 66.2%, and 97.3% for the total population tested. For the high-prevalence (greater than 15%) population the respective values were as follows: 78.6%, 91.5%, 68.8%, and 94.7%. Specimens from females had a lower sensitivity than those from males. In the low-prevalence population (less than 10%) results were as follows: 100%, 97.8%, 50%, and 100%. A cost comparison emphasized the benefit of the Gram's stain and culture. It also indicated that, unless batched or assayed at high volume, Gonozyme is not cost competitive for laboratories using standard culture methods. The impact of the EIA method, in general, and Gonozyme, specifically, on the microbiology section also was investigated. Integration would require altering of established work patterns and loss of flexibility and freedom of standard plating technics. The fact that Gonozyme is a "presumptive" test limits it to being a complementary assay, not an alternative. The authors conclude that Gonozyme is optimally suited to a high-volume laboratory, screening a low-prevalence female outpatient population, where specimen transport is a problem and gonococcal resistance to penicillin has not been demonstrated. This would include sexually transmitted disease clinics, reference laboratories, and state health departments.

Antigens, Bacterial↗
PubMed1984

An analysis of the human brain stem auditory evoked response yielding new criteria for defining its abnormality.

The human brain stem auditory evoked response (BAER) is analysed into 3 main constituent components: a slow background wave, a repetitive wave, and a 3rd (delayed) component which is of relatively short duration, and which does not begin until about 5 ms after the click stimulus. In a group of responses from healthy subjects, the amplitude and latency variabilities of the delayed component are found to be small. In the BAER, as usually recorded from vertex-ipsilateral earlobe electrodes, the peaks I, II, III, IV and VI are identified with the crests of the repetitive wave. Based on this correlation, it is suggested that these peaks may be generated from a common source. Existing criteria for defining abnormality of the BAER are interpreted in terms of the constituent components found from the analysis. New criteria are proposed which involve the amplitudes and latencies of these components.

Acoustic Stimulation↗
PubMed1983

The acquired immunodeficiency syndrome and Mycobacterium avium-intracellulare bacteremia in a patient with hemophilia.

A 27-year-old previously healthy man with hemophilia presented with Pneumocystis carinii pneumonia. The patient had several episodes of oral candidiasis followed by disseminated infection with Mycobacterium avium-intracellulare. He was not homosexual nor did he take illicit drugs, but he had been self-administering two to four monthly infusions of factor VIII concentrate for 7 years. In-vitro lymphocyte studies showed findings consistent with the acquired immunodeficiency syndrome that had previously been reported only in homosexual men, drug addicts, and Haitian refugees. The cause of this syndrome is unknown, but the possibility that it is associated with a transmissible agent acquired through the use of blood products such as factor VIII concentrate must be considered.

Acquired Immunodeficiency Syndrome↗
PubMed1980

The prognosis of the outcome of comatose states.

Fifty different signs of coma are considered, and the twelve most important have been used to score the degree and progress of patients in coma, together with brain stem evoked responses. The inclusion of brain stem signs and symptoms is considered to be an important new element in this classification.

Coma↗
PubMed1977

The ocular microtremor record and the prognosis of the unconscious patient.

Ocular microtremor was recorded in 41 healthy subjects and 70 unconscious patients. Abnormalities of frequency and pattern were found in all the unconscious patients, the degree of abnormality being related to outcome. The ocular microtremor record is a potential aid to prognosis in the unconscious patient.

Adolescent↗