Biomedical subjects

R P Betts

Publications and source records attributed to R P Betts.

At least 19 recordsLinked to original sources

PubMed2000

Comparison of methods for the recovery and detection of low levels of injured Salmonella in ice cream and milk powder.

This study compared the ability of four rapid methods and a standard cultural method to detect low levels of heat-injured cells of Salmonella typhimurium in ice cream and skimmed milk powder. The detection of Salmonella in samples contaminated with low levels (< 10 cfu 25 g-1) was significantly greater with the novel broth method than with the other methods (P </= 0.01). At contamination levels > 10 cfu 25 g-1, there was no significant difference between the methods except for the novel broth method and a dipstick-based immunoassay (P </= 0.05). The novel broth method, S.P.R.I.N.T. Salmonella, which incorporates a specifically formulated peptone and Oxyrase(R) combination followed by the timed release of selective agents into the recovery medium, was shown to improve the rate of detection of low numbers of injured cells of Salmonella after 24 h enrichment.

Animals↗

PubMed2000

The Viladot implant in flatfooted children.

In 1991, Viladot described an implant for the treatment of painless flatfeet in children. This was inserted through a double approach to allow the talus to function while limiting its ability to slide off the calcaneus. The wineglass shaped prosthesis was inserted into the sinus tarsi with a tibialis posterior advancement and soft tissue correction to allow the foot to adopt a neutral position. This is in keeping with other procedures described for the correction of flatfoot. Viladot reported excellent results in 234 feet operated on in such a manner using clinical, radiological and photopodographic parameters. In Sheffield, over three years, 22 implants were inserted for similar painless flatfeet in children. The results were assessed using clinical, radiological and pedobarographic parameters. Viladot was able to demonstrate an improvement in all cases, clinically, radiologically and photopodographically with little or no discomfort and a return to preoperative levels of activity including sport. We found that in all cases, postoperative pain was a major feature which limited activity in all but 2 feet and which reduced the ability to take part in sport and other preoperative pastimes. Unlike Viladot, we were unable to demonstrate consistent improvements radiologically. Pedobarographically, the loading of the first metatarsal head remained unchanged and the centre of pressure was corrected in only 14%.

Adolescent↗

PubMed1998

Rapid and definitive detection of Salmonella in foods by PCR.

The BAX system for screening Salmonella is one of the first commercial PCR-based systems for the detection of food-borne pathogens. It is able to give a confirmed result within 28 h. There was 98.6% and 95.8% agreement between the BAX system and conventional cultural analysis for the detection of Salmonella in artificially inoculated and uninoculated food samples, respectively. In both cases, the BAX system generated more positive detections than cultural analysis. The speed of assay, case of use and high specificity and sensitivity of the BAX system for the detection of food-borne Salmonella make it an attractive method for routine food microbiology laboratories.

Bacterial Typing Techniques↗

PubMed1998

MicroVal: a European approach to the certification of new microbiological methods.

In recent years, food microbiologists have seen the development of a range of nonstandard methods designed to enumerate or determine the presence of various microorganisms in food products. Generally the new methods are designed to give the microbiologist advantages, such as greater automation or faster results, over standard conventional methods. The new methods, however, have often not been thoroughly tested to give the end user confidence in the results. In order to generate data to show that new methods give results that are comparable with standard methods, they must be validated. A number of validation schemes have been developed in various countries throughout the world. There has not, however, been an acceptable scheme recognized throughout Europe. The MicroVal project has been involved in the development of a European microbiological method validation and certification scheme; it involves 21 partners from 7 EU member states. New methods that are tested by the MicroVal system will undergo initial testing in a single expert laboratory, to establish the test's specificity, limit of detection, relative accuracy, sensitivity, and linearity. This testing will be followed by a collaborative study in a minimum of eight laboratories, which will be used to determine the test precision, repeatability, and reproducibility. All results will be assessed by two expert reviewers who will recommend or reject the test. Tests that are recommended will be finally accepted by a MicroVal committee. The committee will pass its comments to one of several certification bodies (working together through a memorandum of understanding) who will certify that the new method gives results that are equivalent to the reference method used throughout the validation work. The technical rules that describe the work required to certify a method are currently being considered by the European Committee for Standardisation (CEN), with the objective that the rules will become a CEN standard for the certification of new test methods. When this objective has been achieved the rules will become an International Standards Organisation (ISO) standard for new test method validation.

European Union↗

PubMed1997

The use of bacteriophage-based systems for the separation and concentration of Salmonella.

Techniques for the separation/concentration of micro-organisms from background food matrices can be applied to increase the speed of analysis and ease of isolation and detection of target micro-organisms. One recent example of such a technique is the immunomagnetic separation (IMS) procedure that has been used for the separation of specific micro-organisms from foods. This paper describes the use of a novel biosorbent consisting of a Salmonella-specific bacteriophage (phage) immobilized to a solid phase that was used for the separation and concentration of Salmonella from food materials. This work has shown that a Salmonella-specific phage-based biosorbent could remove Salmonella from culture fluid and separate Salmonella from suspensions of other Enterobacteriaceae. The ease of production of phage, high affinity of phage-cell interaction and the ability of phage to infect host cells in heterogeneous environments indicates the potential of such a biosorbent as the basis for a reliable separation system in food microbiological analysis.

Bacteriological Techniques↗

PubMed1996

The isolation and detection of Escherichia coli O157 by use of immunomagnetic separation and immunoassay procedures.

The use of immunomagnetic separation (IMS) techniques has been reported to reduce the total test time, and improve the sensitivity, of microbiological tests done on foods. This approach is being adopted in epidemiological investigations into suspected foodborne outbreaks of Escherichia coli O157 infection and has gained acceptance by public health laboratories and the food industry. This study demonstrated the ability of a commercially available IMS procedure, Dynabeads anti-E. coli O157, to enable detection of a few cells of E. coli O157 in 25 g of inoculated minced beef, giving results 1 d earlier than a cultural analysis of similar sensitivity. With correct choice of enrichment broths, IMS may increase isolation rate of E. coli O157 compared to that obtained using conventional cultural methods. It is suggested that this may be due to an increase in relative concentration of E. coli O157 compared with the background microflora present in minced beef, which may reduce reliability of non-IMS detection procedures by masking or mimicking target cells on selective/differential solid media. The use of an immunoassay incorporating an IMS step, EHEC-Tek (Organon-Teknika), enabled detection of a few cells of E. coli O157 in 25 g of minced beef. Comparison of the IMS-ELISA with a standard ELISA procedure (Tecra) indicated the sensitivity of the latter system to be greater, perhaps resulting in the higher isolation rate. The use of a method to reliability isolate and detect extremely low levels of E. coli O157 in a food is necessary to aid reduction in the incidence of this most serious of foodborne pathogens.

Animals↗

PubMed1995

Evaluation of methods for the isolation and detection of Escherichia coli O157 in minced beef.

This study has evaluated enrichment and detection procedures for the isolation and detection of Escherichia coli O157 inoculated into minced beef. The use of a 24 h enrichment in modified EC broth containing novobiocin allowed low numbers of contaminating cells to multiply to levels detectable on culture media and by ELISA test kits. Total analysis time was reduced by the use of the Dynabead immunomagnetic separation system. The use of the Petrifilm Test Kit-HEC for E. coli O157:H7 and Organon Teknika EHEC-TEK system detected low numbers of contaminating cells following enrichment and reduced analysis time by 1 d. The incorporation of cefixime and tellurite into Sorbitol MacConkey Agar increased the rate and ease of isolation of E. coli O157 and its use is therefore recommended.

Animals↗

PubMed1993

Severe peripheral neuropathy and elevated plantar pressures causing foot ulceration in pituitary gigantism.

We report two patients with treated pituitary gigantism and peripheral neuropathy, one of whom has chronic foot ulceration. Detailed neurophysiological assessment was performed on both patients. The patient with foot ulceration had clinical and neurophysiological evidence of severe neuropathy, whereas the patient without ulceration had only neurophysiological abnormalities. The sweating response to acetylcholine was markedly impaired in the feet of both patients, suggesting pedal autonomic denervation. Neither patient had evidence of diabetes mellitus and detailed investigation failed to reveal an alternative cause of peripheral neuropathy. Optical pedobarography revealed abnormally high pressure (> 10 kg/cm2) under the metatarsal heads of both patients, one such area coinciding with the area of ulceration. Thus in pituitary gigantism elevated plantar pressures may contribute to the development of foot ulceration when severe peripheral neuropathy is present. Furthermore, as in diabetes mellitus, impaired sweating may also increase the risk of ulceration as the resultant dry skin may develop fissures.

Adult↗

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↗