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Biomedical subjects

A Latham

Publications and source records attributed to A Latham.

At least 19 recordsLinked to original sources
PubMed1990

The accuracy of predictions about progress of patients on a stroke unit.

The aim of the study was to check the accuracy of predictions about the factors which affect the progress, in physical abilities and activities of daily living, of patients admitted to a stroke unit. A series of 60 patients admitted consecutively to a stroke unit were assessed on tests of motor, functional and cognitive abilities at admission. On the basis of these assessments predictions were made about the abilities of the patients at discharge. Patients were assessed for level of motor abilities and activities of daily living at discharge and the accuracy of the predictions checked. Predictions were found to be significantly correlated with outcome but the relationships were not so close as to be useful for the clinical management of individual patients.

Activities of Daily Living↗
PubMed1988

The effects of TRH analogues on cerebral ischaemia produced by middle cerebral artery occlusion in the rat.

This study examined the effects of two stabilised analogues of TRH, RX 77368 and CG 3509, in a rat cerebral ischaemia model produced by unilateral occlusion of the middle cerebral artery. The analogues were given intraventricularly after artery occlusion. The extent of the cortical ischaemia was evaluated after 10 days by somatosensory evoked potential (SEP) recording, followed by tetrazolium staining of brain slices for NADH-diaphorase activity. RX 77368 (2 X 10 micrograms; 15 min, 24 h) significantly improved the survival rate, protected the SEP and reduced the area of infarct. In contrast, neither a smaller dose of RX 77368 (2 X 3 micrograms) nor a 4 h delay in the treatment had any significant beneficial effects. Although CG 3509 (2 X 10 micrograms) resulted in an apparent improvement in survival, its overall effects were not statistically significant. The findings indicate that stabilised TRH analogues may have beneficial effects when given to animals with focal cerebral ischaemia.

Animals↗
PubMed1987

Rat middle cerebral artery occlusion: use of evoked potentials and tetrazolium staining to assess chronic ischaemia.

This study examined the effects of permanent, unilateral cerebral artery occlusion on the somatosensory evoked potential (SEP) recorded from the ipsilateral cortex in the anaesthetised rat. Ten days after artery occlusion the SEP was absent in the majority of rats tested and in the remainder the wave amplitude was reduced compared to the potential recorded from the normal hemisphere but latency was unaffected. Histochemical staining with Tetrazolium for infarct size has shown that loss of the SEP correlated with ischaemic damage to the cortex. SEP recording can be used to assess the extent of cortical ischaemia in this small animal model.

Animals↗
PubMed1986

Rapid identification of coxsackie B viruses after immunoprecipitation and nucleic acid hybridization.

To circumvent the difficulties in concentrating sufficient virus from a clinical or environmental sample for detection and identification, we have used immunoprecipitation to rapidly concentrate coxsackie B viruses from both large and small sample volumes. Antiviral serum and killed Staphylococcus aureus cells as a protein A source were used to bind and collect the virus. Radioactively-labeled viral nucleotide sequences were used to identify the collected virus by nucleic acid hybridization. The technique is applicable to the rapid concentration of dilute viruses from extremely large sample volumes as well as the samples from which virus isolation can be difficult. the process requires less than 2 days to complete and should be adaptable to virus identification by cell culture or other standard means as well.

Animals↗
PubMed1982

Pharmacokinetics of meptazinol in man following repeated intramuscular administration.

A study was performed in 6 healthy volunteers to determine whether 50 mg intramuscular doses of meptazinol repeated four hourly for 24 h would lead to accumulation of the drug. The first dose of meptazinol was rapidly absorbed with a subsequent mean (+/- SD) elimination half-life of 1.6 +/- 0.33 h. This value was unaffected by the administration of intermediate doses. There was no significant accumulation of the drug; 95% of the steady-state plasma concentration was achieved after a mean (+/- SD) of 1.9 +/- 0.39 and 99% after a mean (+/- SD) of 2.9 +/- 0.63 doses. These findings are consistent with the theoretical prediction for a rapidly absorbed drug with a plasma elimination half-life of 1.6 h. No clinically relevant changes were seen in pulse blood pressure, haematological or biochemical screens. Reported side effects were of a subjective and minor nature.

Adult↗
PubMed1982

Comparison of cerebellar Purkinje cell simple spike discharges in adult rats after undernutrition during the suckling period and nutritionally normal rats.

The spontaneous activity of cerebellar Purkinje cells was compared in 100- to 130-day-old rats undernourished during the suckling period (i.e. 0-21 days) and subsequently nutritionally rehabilitated (PU rats), with that in rats of the same strain and of similar age fed normally (age controls), and in normally fed rats of the same strain but approximately one month younger (weight controls). Simple spike activity of single cells was recorded with extracellular microelectrodes in pentothal-anaesthetized animals. The discharge patterns were assessed by on-line computer analysis of the interspike interval distributions with subsequent transformation of the data to enable the results to be evaluated by an analysis of variance. In addition, the distribution of the mean interval, the percentage of intervals less than 30 ms, the percentage of intervals greater than or equal to 150 ms, and the time spent in intervals greater than 150 ms, were compared for the PU rats and pooled controls by a nonparametric statistical test on the untransformed data. None of the results indicated that there were any significant differences between the simple spike activity of Purkinje cells from age- and weight- control rats nor between that in PU rats and the control groups. These results are discussed in relation to the previously reported deficits of granule cells in the cerebella of PU rats.

Action Potentials↗
PubMed1980

Combined study of the pattern of spontaneous activity of cerebellar Purkinje cells and phenytoin serum levels in the rat.

The effects of phenytoin (PHT) on the spontaneous activity of cerebellar Purkinje cells and the drug serum levels have been examined following both intravenous and intraperitoneal administration in rats. Purkinje cell activity was assessed by on-line computer analysis of interspike interval distributions. PHT levels were assayed in blood samples taken at the end of the electrophysiological experiments and in successive samples obtained in parallel experiments over periods corresponding to when electrophysiological recordings were made. Single intravenous doses of PHT (10 mg/kg) produced a decrease in the discharge rate in individual Purkinje cells with a time course which was delayed and prolonged compared with the changes in serum levels of PHT. A single intraperitoneal dose of PHt (100 mg/kg) produced a statistically significant (p < 0.02) decrease in Purkinje cell discharge rate. Similar results (p < 0.01) were obtained after pretreatment with PHT (50 mg/kg daily for 14 days, including the day of the experiment). Both injection schedules produced nontoxic serum PHT levels during the recording period. Pretreatment with PHT doses of 10 mg/kg for 14 days (including the experimental day) produced a smaller decrease in Purkinje cell discharge rate (p < 0.05). When pretreatment ceased the day before the electrophysiological experiment, no significant changes in Purkinje cell activity were observed, and serum PHT levels were not detectable at the end of the experiment. None of the pretreatment schedules produced overt signs of cerebellar dysfunction or motor impairment. These findings indicate that PHT may increase the output from the cerebellum by suppressing Purkinje cell activity. Since this effect occurs without producing cerebellar symptoms, it may account for some of the therapeutic action of PHT at nontoxic levels in man.

Animals↗
PubMed1971

Spontaneous activity of cerebellar Purkinje cells and their responses to impulses in climbing fibres.

1. Spontaneous discharges and evoked responses of Purkinje cells have been studied in the anterior lobe vermis of the cerebellum in cats anaesthetized with thiopentone sodium.2. Spontaneous activity was of two kinds: (a) single spikes which occurred in long trains and were discharged at average frequencies of 50-125/sec and (b) burst responses due to climbing fibre (CF) activation of the cell. These occurred at an average frequency close to 1/sec.3. CF responses were evoked by either stimulation of the Abeta fibres of the superficial radial nerve (SRN) or by an electrode inserted into the deep white matter near the fastigial nucleus (JF electrode).4. A suppression of the discharge of single spikes was frequently observed to follow a CF response, whether it occurred naturally or was produced by a stimulus. These pauses in spontaneous discharge (post-CF pause) lasted for approximately 100 msec, but they did not have a one-to-one relationship with the CF responses. Occasionally a pause in the spontaneous activity was elicited by stimuli that failed to evoke the cell.5. For a period following a peripheral stimulus, a Purkinje cell could not be further excited by a second peripheral stimulus (interaction). JF stimulation could still excite the cell. Evidence was obtained that there was no significant inhibition during the period of depressed excitability to peripheral stimulation.6. The control over the input of activity to the cerebellum through the CF system appears to be imposed at an extra-cerebellar site. The olivary nuscles was suggested as a strong possibility.7. Some possible mechanisms responsible for the post-CF pause were discussed. Disfacilitation of Purkinje cells by suppression of granule cell discharges seems to give the best fit to the data.

Action Potentials↗