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Biomedical subjects

S Freeman

Publications and source records attributed to S Freeman.

At least 181 records · Page 10Linked to original sources
PubMed1987

Respiratory questionnaires in occupational studies: their use in multilingual workforces on the Witwatersrand.

The mother tongue of the majority of black workers in the industrial workforces of the Witwatersrand is either Zulu or S Sotho/Tswana, and these are also the main languages spoken in the area. However a substantial minority cite one of several other languages as their mother tongue. In consequence, in occupational surveys using a respiratory questionnaire, the accepted practice has been to use multilingual interviewers who administer the questionnaire in whichever of the two main languages the interviewee requests, but work from an English language version. To test the reproducibility of the information so gathered, a standardized questionnaire was administered to 56 subjects on two occasions approximately three weeks apart by each of two interviewers, one of whose mother tongue was Zulu and the other S Sotho. Reproducibility was little affected by whether the interviewer used her mother tongue or not, pointing to the multilingual competence of both interviewers. Reproducibility was, however, less in subjects not interviewed in their mother tongue compared to those who were. In general, reproducibility was also less for symptom than for history questions, though the phlegm question performed comparably to that reported for more homogeneous language/ethnic groups. Thus, even if internally valid, respiratory symptom information obtained by this method may have limited generalizability. However respiratory history information appears more reliable and may prove of value in the investigation of the natural history of chronic lung disease in this and similar communities.

Adult↗
PubMed1987

Immunological, histological and biochemical assessment of brown adipose tissue activity in neonatal, control and beta-stimulant-treated adult dogs.

Significant levels of mitochondrial uncoupling protein were demonstrated on neonatal dog mitochondria prepared from perirenal, bladder and subcutaneous adipose tissue sites. The protein was not detected in homogenates of adipose tissue samples from the same sites in adult, control dogs. However, chronic treatment of adult dogs with a beta-stimulant (LY 79730) led to the appearance of detectable amounts of uncoupling protein in perirenal and bladder but not subcutaneous adipose tissue depots. Decreases in mean cell diameter, increases in the frequency of multilocular cells and of cytochrome oxidase and creatine kinase were also associated with the effects of treatment on dog adipose tissue. The results demonstrate the age-related decline in dog brown adipose tissue and its reversal by chronic treatment with beta-stimulant.

2-Hydroxyphenethylamine↗
PubMed1986

Multi-modality evoked potentials in hypoxaemia.

The auditory nerve-brain-stem evoked response (ABR) has been shown to be insensitive to hypoxic inspiratory gas mixtures which severely depress the EEG. In order to determine the relative sensitivities of additional brain regions and pathways to hypoxaemia, anaesthetized paralysed cats were ventilated with various gas mixtures while recording the evoked responses of the auditory, somatosensory (including peripheral nerve, brain-stem and primary cortical components), visual and vestibular systems. Arterial blood pressure was maintained by dopamine infusion and pH was corrected with bicarbonate. Hypoxic gas mixtures (6-7% O2) presented for 60 min, causing severe hypoxaemia (paO2 20-30 mm Hg; O2 saturation 25-50%), were without effect on the somatosensory, vestibular and visual EPs while the auditory evoked potentials (ABR and cortical components) were depressed. However, if arterial blood pressure was allowed to fall, all of the evoked potentials became severely depressed and isoelectric. These results and others indicate that the cortical components are qualitatively similar to the more peripheral evoked potentials. The resistance of these evoked potentials to controlled hypoxaemia is probably due to their generation by oligosynaptic pathways and to a compensatory switch to anaerobic metabolism and to an elevation of cerebral blood flow.

Animals↗
PubMed1986

The depression of the auditory nerve-brain-stem evoked response in hypoxaemia--mechanism and site of effect.

During severe hypoxaemia in the cat the ABR was depressed in 2 different patterns: if mean arterial blood pressure (MAP) was maintained then all other evoked potentials (EPs--somatosensory and visual) remained. If MAP was not maintained, all of these EPs were depressed. This study sought to document these different patterns of ABR depression and to ascertain their mechanisms. When MAP fell, the ABR loss began with the later waves and progressed to the earlier waves. These are signs of a central brain lesion. The hypoxaemia, detrimental to normal function of the cardiovascular system, leads to depression of MAP, to a fall in cerebral perfusion pressure and blood flow, to cerebral ischaemia and ABR loss. On the other hand, when MAP was maintained, severe hypoxaemia was accompanied by a depression of all of the ABR waves at the same time. The cochlear microphonic potential was also simultaneously depressed. These are signs of a peripheral, cochlear effect similar to the demonstrated depression of the positive endocochlear resting potential of the scala media and of the cochlear microphonic potential during hypoxaemia. This leads to interference with the cochlear transduction mechanism so that all of the auditory evoked potentials, including the ABR, are simultaneously depressed. These results lead to the suggestion that the ABR abnormalities seen in patients who suffered a hypoxic (anoxic) insult or an ischaemic episode (prolonged interpeak latencies, loss of later waves and finally all waves absent or only the first wave remaining) is always due to ischaemia even when the initial insult was hypoxic.

Animals↗
PubMed1986

A computerized approach to the collection and analysis of cardiac action potentials.

A description is given of a microcomputer system for the collection and storage of cardiac action potentials. The equipment required is commercially available and easy to use. Analysis of the data is performed off-line with a mainframe computer. A description of the software used for both data collection and data analysis is given.

Action Potentials↗
PubMed1986

Woman allergic to husband's sweat and semen.

A woman complained of severe itching and flushing after sexual intercourse or other physical contact with her husband. She developed a weal and flare on intradermal testing with her husband's semen and sweat, pooled donor semen and the sweat from her 2 sons. This is a report of allergy to human semen and the 1st reported case of allergy to human sweat.

Adolescent↗
PubMed1986

Urologic procedures.

The relief of bladder outlet obstruction can be accomplished by several procedures. In the absence of trauma, the simplest of these is passage of a Foley catheter. When the genitourinary system has been subjected to trauma, it is important to assess its integrity before instrumentation is performed. Radiographic assessment is performed most often with the use of contrast media.

Emergencies↗
PubMed1985

The persistence of somatosensory and auditory pathway evoked potentials in severe hypoglycemia in the cat.

In a previous study it was shown that during severe insulin-induced hypoglycemia in rats and cats (0.38 mmol/l, i.e., 6.8 mg% and 0.8 mmol/l, i.e., 14 mg% respectively) with isoelectric EEG, the latency and amplitude of the auditory nerve-brain-stem evoked responses were not affected. In the present study on cats, the above evoked responses were complemented by recording in addition the cortical auditory evoked potential and the peripheral, brain-stem and cortical components of the somatosensory evoked potentials. Each of these evoked potentials remained in the presence of 0.75 mmol/l glucose in plasma. The persistence of the somatosensory cortical evoked potential was unexpected since two other groups have reported the disappearance of this potential during hypoglycemia. The types of neuronal activity which can still be recorded in severe hypoglycemia are probably generated by neuronal structures with lower metabolic demands such as axons and oligosynaptic pathways, surviving on the consumption of endogenous substrates with compensatory elevation of local cerebral blood flow.

Animals↗