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Biomedical subjects

R P Betts

Publications and source records attributed to R P Betts.

At least 19 recordsLinked to original sources
PubMed1990

The importance of the valgus hindfoot in forefoot surgery in rheumatoid arthritis.

The relationship between hindfoot deformity and forefoot pressure was assessed in 28 rheumatoid patients who had undergone forefoot reconstruction four years previously. Patients with valgus hindfoot deformities tended to have high forefoot pressures whereas those with a normal hindfoot recorded normal pressures on the dynamic pedobarograph. All patients with residual forefoot pain recorded abnormal forefoot pressures. We believe that orthotic control of hindfoot deformities should be considered for those patients who require forefoot surgery as a combination of surgical and orthotic management may offer the best chance of success.

Adult↗
PubMed1989

Abnormal foot pressures alone may not cause ulceration.

Both rheumatoid arthritis and diabetes have been associated with the development of abnormally high pressures under the feet, and ulceration has been considered to be a problem in both conditions. In order to examine further the relationship between high foot pressure, neurological abnormalities, and ulceration, we have studied two groups of patients: (a) 38 diabetic patients and (b) 37 patients with rheumatoid arthritis who had similar clinical abnormalities of the feet. Thirty-two percent of diabetic patients had a history of plantar ulceration compared with none of the rheumatoid group (p less than 0.01). However, the diabetic group had considerably more severe neuropathy (peroneal nerve motor conduction velocity 35.4 +/- 4.8 m s-1 vs 44.4 +/- 5.2 m s-1 (mean +/- SD), p less than 0.001; vibration perception threshold 33.5 +/- 13.4 vs 16.9 +/- 10.9, p less than 0.001), with a similar frequency of elevated plantar pressures (51% vs 61%, NS). These data emphasize the importance of the loss of sensory awareness in the pathogenesis of diabetic foot ulceration, and suggest that high pressure alone is not a direct cause of ulceration.

Arthritis, Rheumatoid↗
PubMed1989

A prospective study of forefoot arthroplasty.

The Kates et al. metatarsal head resection arthroplasty has been modified and evaluated clinically and objectively using a dynamic pedobarograph in 35 adult rheumatoid arthritis patients. Preoperatively, all patients complained of severe forefoot pain, but only 70% recorded abnormal plantar pressure measurements. After a mean follow-up time of 36 months, 91% of the patients were satisfied with the result following surgery. Forty-two feet were pain-free, 16 feet still painful but less than preoperatively, and two feet worse. Thirteen of the 18 painful feet recorded abnormal pressure, but 16 additional feet with normal pressures were symptomatic. The clinical and pedobarographic results show that, in the majority of patients, the Kates et al. forefoot arthroplasty relieves pain, improves mobility, effectively decreases high abnormal plantar pressures, and should be considered when conservative methods of treatment have failed.

Adult↗
PubMed1988

Selection of transducer material for use with 'optical' foot pressure systems.

'Optical' foot pressure systems, or pedabarographs, use a white plastic or rubber material as the transducer. In the past, materials have been used which are not appropriate for calibrated measurements, particularly in dynamic studies (i.e. walking measurements). We describe a simple method for selecting transducer materials and make comparisons between commonly used materials.

Calibration↗
PubMed1988

The detection of irradiated foods using the Direct Epifluorescent Filter Technique.

A method was evaluated which has the potential to detect a food sample which has been irradiated. The technique will give an indication of the total number of viable micro-organisms present before irradiation. It is based on the comparison of an aerobic plate count (APC) with a count obtained using the Direct Epifluorescent Filter Technique (DEFT). When the APC of an irradiated sample was compared with the DEFT count on the same sample, the APC was considerably lower than that obtained by DEFT. The count of orange fluorescing cells after irradiation, however, correlated well with an APC of the same sample before irradiation. For the samples examined the DEFT count determined the viable microbial population in the sample before irradiation. The difference between the APC and the DEFT count gave the number of organisms rendered non-viable by the process.

Animals↗
PubMed1988

The use of direct epifluorescent microscopy (DEM) and the direct epifluorescent filter technique (DEFT) to assess microbial populations on food contact surfaces.

Two rapid methods, direct epifluorescent microscopy (DEM) and the direct epifluorescent filter technique (DEFT) on swab resuspension fluids, were compared with the traditional total viable count (TVC) on swab resuspension fluids for their ability to enumerate surface populations of attached bacteria. The degree of error in estimating surface populations was shown to be significantly less with DEM than DEFT followed by TVC. DEM estimated populations in the range 3 x 10(3) to 5 x 10(7) colonies/cm2 whilst DEFT enumerated populations above 3 x 10(4) colonies/cm2 and TVC above 3 x 10(5) colonies/cm2 (as measured by DEM). Swabbing was shown to remove a constant proportion of organisms from the surface populations tested, although below 3 x 10(5) colonies/cm2 most of the organisms remained in the cotton matrix and were difficult to resuspend. DEFT was more able to enumerate swab resuspension fluids obtained from surface populations below 3 x 10(5) colonies/cm2 than was TVC.

Acinetobacter↗
PubMed1988

Reduced hyperaemic response under the diabetic neuropathic foot.

Diabetic neuropathic ulcers typically occur at high pressure sites. Microvascular blood flow has been assessed on the plantar surface of the foot in three matched groups each of 12 subjects free from macrovascular disease: (a) patients with diabetic neuropathy with abnormal foot pressures and previous neuropathic ulceration; (b) non-neuropathic diabetic patients; (c) non-diabetic control subjects. Resting flow was measured at the highest pressure point under the metatarsal heads (defined by pedobarograph) using laser doppler flowmetry, and the hyperaemic response was assessed at the same site following 3 min standing. Peak flow was significantly reduced in neuropathic patients (2.3 +/- 1.4 (SD) volts) compared with control subjects (4.0 +/- 2.0 volts; p less than 0.03). The time for blood flow return to baseline was significantly prolonged in neuropaths (159 +/- 72 s) compared with normal subjects (93 +/- 18 s; p less than 0.01), with a significant delay also seen in non-neuropaths (151 +/- 38 s; p less than 0.0001 compared with normal).

Adult↗
PubMed1988

Foot pressure studies in the assessment of forefoot arthroplasty in the rheumatoid foot.

To assess the results of forefoot arthroplasty, dynamic and static foot pressure studies have been made of the rheumatoid foot in both a prospective study group of 60 feet and in a retrospective study group of 18 feet. Significant reductions of pressure in the forefoot were found. Problems associated with the first and fifth metatarsals were considered.

Adult↗
PubMed1987

The natural history of foot pressure abnormalities in neuropathic diabetic subjects.

The pressures under the feet of 39 subjects with diabetic neuropathy were initially assessed during walking using an optical pedobarograph. The upper limit of normality for pressure readings in non-diabetic subjects had previously been established as 10 kg/sq.cm. These subjects were then followed for a mean period of 3 years after which foot pressure studies were repeated. 39 feet had abnormal results when initially studied, compared with 33 at the follow-up study (p = NS). However, changes in the distribution of pressure under the metatarsal heads were seen in 13 feet, while 20 feet showed changes in abnormal pressures under the same site. Recurrent metatarsal ulcers occurred in 6 feet during the study, with 5 occurring at documented sites of high pressure. It is concluded that important changes in the distribution and level of pressures under diabetic neuropathic feet occur during a relatively short time. As it has previously been demonstrated that increased foot pressures are associated with foot ulceration, it is important for the orthotist to re-assess the feet regularly to establish whether significant changes in pressure distribution that might warrant new insoles or footwear have occurred.

Adult↗
PubMed1986

Os calcis osteotomy in the management of deformities of the hindfoot in spinal dysraphism.

The results of 52 primary os calcis osteotomies in 44 patients with spinal dysraphism are reviewed. There were 42 varus hindfoot deformities and ten valgus hindfoot deformities. The results indicate that the operation is simple and uncomplicated, but over a mean 5.8 year follow-up for the varus feet and 6.5 years for the valgus feet, over 50% of the feet developed either a moderate or severe recurrence of deformity. Os calcis osteotomy appeared from this series to be a moderately successful interim operation for the equinus varus foot, delaying the need for premature triple arthrodesis, but the long-term results in cavo-varus feet with claw toes were uniformly poor. Furthermore, it appeared to be unsatisfactory in the mobile flail valgus foot unless the subtalar joint had been stabilised by fusion. Correction of proximal joint or bone deformity and muscle imbalance is considered necessary if satisfactory results are to be achieved from the osteotomy.

Adolescent↗
PubMed1985

Plantar pressure measurements and the prevention of ulceration in the diabetic foot.

Static and dynamic measurements of foot pressure have been carried out on three groups of subjects: diabetic patients with neuropathy (with and without a history of ulceration), diabetic patients with no neuropathy, and normal subjects as controls. In many cases both techniques of measurement detected areas of abnormally high pressure under the foot, but in some cases a particularly high-pressure spot was detected on only one of the tests and sometimes both methods were needed to reveal all the areas of the foot which might be considered to be at risk. The dynamic measurements tended to show multiple areas of high pressure better than the static measurements. Our results indicate the importance of making both types of measurement when seeking to devise suitable means of protecting the foot from ulceration.

Diabetes Mellitus↗
PubMed1985

Neuropathic ulcers of the foot.

We report a prospective study of the causes and treatment of 26 long-standing neuropathic ulcers of the foot in 21 patients. The most important causal factor, well illustrated by pressure studies, was the presence of a dynamic or static deformity leading to local areas of peak pressure on insensitive skin. All but one of the 26 ulcers had healed after an average of 10 weeks of treatment in a light, skin-tight plaster cast, with the prohibition of weight-bearing. Recurrent ulceration was prevented in all but one foot by early operation to correct the causative deformity; this was performed after the ulcer had healed and before allowing weight-bearing on the limb. Pressure studies after operation confirmed that pressure points had been relieved.

Adolescent↗
PubMed1984

Sulphur oxidation by a Streptomyces sp. growing in a carbon-deficient medium and autoclaved soil.

Streptomyces colonies, apparently all of the same species, were isolated from a range of soils using a polysulphide medium lacking an organic carbon source. Growth on this medium, and clearing of the otherwise white, opaque overlay, suggested that the organisms were capable of growing autotrophically. However, investigation of one of these isolates showed that it was unable to fix 14CO2 and did not possess the enzyme ribulose bisphosphate carboxylase, showing that it was incapable of autotrophic growth. The isolate oxidized elemental sulphur, thiosulphate and tetrathionate to sulphate in vitro in carbon-deficient medium, and also oxidized elemental sulphur to sulphate when inoculated into autoclaved soil supplemented with sulphur. It also oxidized polysulphide when growing on Czapek Dox and plate count agars. The isolate can therefore grow heterotrophically in both carbon-rich media and in media lacking organic carbon - presumably by scavenging organic carbon from the laboratory atmosphere. The possible role of these organisms in sulphur oxidation in soils is commented upon.

Carbon↗
PubMed1978

Nerve fibre refractory period in patients treated with rubidium and lithium.

Nerve fibre refractory period distributions have been measured on the median nerves of six manic-depressive patients controlled with lithium carbonate, three chronic patients (two manic-depressives and one catatonic schizophrenic) controlled with rubidium chloride, and eight normal volunteers. Rubidium prolonged the refractory periods of all nerve fibres while lithium increased only the longer refractory periods.

Adult↗