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Biomedical subjects

A Hunter

Publications and source records attributed to A Hunter.

At least 91 records · Page 5Linked to original sources
PubMed1995

The response of mouse skin to fractionated doses of fast neutrons (66 MeVp-Be) with variable interfraction and overall treatment times.

PURPOSE: Beam availability for neutron therapy at the National Accelerator Centre at Faure, South Africa is such that treatment fractions are given at irregularly spaced intervals. Such treatment scheduling may not be optimal. METHODS: Investigations were made using the acute skin reaction of the mouse foot to determine the effect of different numbers of regularly and irregularly spaced fractions of p(66)/Be neutrons. Assessment of results was both by average skin reaction and by ED50 values for the incidence of moist desquamation as established by probit analysis. RESULTS: Different numbers of fractions (between 6 and 11) and different times between fractions did not appear to affect the mouse foot response significantly when fractionation was completed within 11 days, i.e. before repopulation began to have an effect. When overall treatment times were longer than 11 days, the mouse foot responses to 6 and 9 fractions with variable interfraction times were similar, provided the overall treatment times were the same and the fractions were at least 24 h apart. The alpha/beta ratio was 87 +/- 27 (SE) Gy for the early response of the BALB/c mouse foot skin to p(66)/Be neutrons. CONCLUSIONS: The response of mouse skin to fractionated p(66)/Be neutrons was independent of fraction number or interfraction time, provided that the overall treatment time was the same.

Animals↗
PubMed1995

Engraftment characteristics of peripheral blood stem cells mobilised with cyclophosphamide and the delayed addition of G-CSF.

The optimal protocol for the mobilisation of PBSC remains unknown. We present data on 42 patients mobilised with cyclophosphamide (3 or 4 g/m2) and the delayed addition of a standard 300 micrograms dose of G-CSF (Filgrastim) from day +5. The patients had received a median of 2 previous chemotherapy regimes, 38% had received prior radiotherapy and 38/42 had active disease at the time of mobilisation. The protocol was well tolerated and 38 patients proceeded to transplantation. The median number of CD34+ cells reinfused was 4.3 x 10(6)/kg (range 0.5-30) and CFU-GM 15.8 x 10(4)/kg (range 0-148). The total number of CD34+ cells harvested correlated with the total number of CFU-GM available for reinfusion (P = 0.008). Overall engraftment occurred within median days to neutrophils > 0.5 x 10(9)f/l or platelets > 20 x 10(9)/l of 14 and 13 days, respectively. Patients receiving more than 2.5 x 10(6)/kg CD34+ cells had even more rapid haemopoietic reconstitution with significant reductions in hospital stay and transfusion requirements. Those below this threshold had significantly delayed platelet engraftment. The mobilising dose of cyclophosphamide did not influence the achievement of the threshold CD34+ cell yield for optimal engraftment. The delayed addition of a standard 300 micrograms G-CSF dose after priming chemotherapy resulted in the use of a median 9 days hence 9 vials of G-CSF. This protocol presents the potential for cost saving without compromising the quality or success of PBSC mobilisation.

Adult↗
PubMed1994

Transperineurial capillary abnormalities in the sural nerve of patients with diabetic neuropathy.

Morphometric techniques were employed to assess perineurial capillary abnormalities in the sural nerve of 20 diabetic patients with neuropathy and 10 normal control subjects. Structural abnormalities were related to quantitative neurophysiological and neuropathological measures of neuropathy. Perineurial capillary endothelial cell area (P < 0.001) and endothelial cell profile number (P < 0.01) were increased and luminal area (P < 0.001) was reduced in diabetic patients when compared with control subjects. A significant relationship was observed between endothelial cell hyperplasia and measures of neuropathic severity. These findings provide evidence for perineurial capillary luminal occlusion due primarily to both endothelial cell hypertrophy and hyperplasia. Such a reduction in luminal size is expected to reduce transperineurial and hence endoneurial blood flow, resulting in endoneurial hypoxia and hence human diabetic neuropathy.

Adult↗
PubMed1993

Long-term increases in the numerical density of synapses in the chick lobus parolfactorius after passive avoidance training.

Passive avoidance training has been shown to cause an increase in synaptic density (Nvsyn) in the lobus parolfactorius (LPO) of the one-day old chick. The present study was conducted to investigate the time-course over which this plastic change takes place. Two groups of chicks were trained to peck at either a water coated bead (Control) or a methyl-anthranilate coated bead (M-trained). M-trained chicks showed avoidance responses when offered a similar but dry bead, 30 min later. Right and left hemisphere LPOs were obtained at intervals of 1, 6, 12, 24 and 48 h after training. Synaptic counts were made using a 3-dimensional stereological probe; the 'dissector'. A significantly larger mean Nvsyn (31%) was found in the left hemisphere of M-trained chicks 24 h after training, compared with Control chicks, and the difference fell to 10% at 48 h post-training. M-trained chicks also had a greater Nvsyn (17%) in the right hemisphere at 48 h post-training. The bilaterality of these findings is of particular interest, since unilateral lesions of the LPO fail to produce amnesia for the avoidance task. The importance of these results in the process of memory formation is discussed.

Analysis of Variance↗
PubMed1992

Who does what?

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Allied Health Personnel↗
PubMed1992

The correlation of age of onset with CTG trinucleotide repeat amplification in myotonic dystrophy.

The gene for myotonic dystrophy (DM) has recently been isolated and amplification of an unstable CTG trinucleotide repeat, located within the DM gene, has been identified in virtually all patients studied to date. A high proportion of DM families who are studied show a progressively earlier age of onset with succeeding generations and, in the few pedigrees reported so far, an increasing degree of amplification of the CTG repeat has been noted to parallel this trend. It has been implicit in several of the original reports on the nature of the changes in the DM gene that knowledge of CTG amplification status at the DM locus of a person will provide useful information concerning prognosis. However, no studies of genotype-phenotype correlation have been reported and there are no specific data on which to base such counsel. In this paper we report the correlation between the degree of CTG amplification and age of onset in 109 DM gene carriers from 17 families. Included are parent-child and sib-sib comparisons which provide a framework in which to incorporate DNA diagnostic studies when counselling subjects and families at risk for DM.

Adolescent↗
PubMed1990

Diagnosis of gestational diabetes in Australia: a national survey of current practice.

A national survey of pathology laboratories revealed a great diversity in the use of screening tests, and in the performance and interpretation of oral glucose tolerance tests for the detection of gestational diabetes. This situation is unsatisfactory and highlights the need for rationally established procedures and diagnostic criteria.

Australia↗
PubMed1990

Standard bearers.

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Physical Therapy Modalities↗
PubMed1990

The popliteal pterygium syndrome: report of a new family and review of the literature.

This paper reports on a family with popliteal pterygium syndrome (PPS), which was ascertained through a baby with most of the major signs of the syndrome. The mother, who had a repaired cleft palate and toe syndactyly, had been aware that her syndactyly was familial, but her unpreparedness for the birth of a child with PPS led to interest in, and a subsequent review of, the differnetial diagnosis and the variable expression of the clinical manifestations of this syndrome. Upon review, some earlier reported cases were excluded as PPS, and certain ascertainment and reporting biases that could affect such an analysis were considered.

Diagnosis, Differential↗
PubMed1990

Cuing efficiency in a Stroop-like task with visual half-field presentation.

Stroop-like stimuli were presented to either the left or the right visual half-field. Subjects responded to the identity of the words above and below (the target dimension), which appeared above or below a reference point (the cuing dimension). Automatic Stroop-like effects were assessed as the difference in reaction times between congruent trials (e.g., above the reference point) and incongruent trials (e.g., above below the reference point) when both trial types were equally frequent. In blocks in which most trials were of one type (e.g., 80% congruent trials), controlled Stroop-like effects could be assessed. Automatic Stroop-like effects remained unchanged under different task manipulations. In contrast, controlled Stroop-like effects were reduced by lowering cue-response compatibility and by increasing the response alternatives from two to four. Thus, similar to other cuing effects, controlled Stroop-like effects are susceptible to manipulations that affect the response-decision stage and appear to involve response-selection processes. The resources supporting these response-selection decisions were not hemisphere-specific, and were sufficiently nonspecific that interference from a memory-load task was found. When resources were scarce, a consistent bias to attend to stimuli presented or responded to on the right was evident.

Adult↗