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Biomedical subjects

M Lord

Publications and source records attributed to M Lord.

At least 19 recordsLinked to original sources
PubMed1992

Interface load analysis for computer-aided design of below-knee prosthetic sockets.

A finite-element analysis is made for the compression of soft tissues of the residual lower limb contained in a prosthetic socket. The analysis is relevant to static loading during stance in a patellar-tendon-bearing, below-knee design of socket. Values of Young's modulus are obtained experimentally for use in the model. One of the main objectives is to study the sensitivity of the loading to these values and also to other assumed conditions. Using direct pressure at the limb/socket interface and vertical stiffness as indicators, changes in material properties, socket alignment and socket rectification are investigated; assumptions about the frictional characteristic at the interface are seen to be critical in determination of load distribution. This type of analysis may provide the next stage of refinement for computer-aided socket design systems.

Artificial Limbs↗
PubMed1992

Method for in-shoe shear stress measurement.

A methodology is described for use of a shear transducer, based on a magneto-resistive principle, to measure stresses under the plantar surface of the foot in-shoe during walking. Particular attention is paid to a projected application for study of diabetic plantar ulceration and its management by footwear. The transducer has a disc construction, approximately 4 mm thick by 16 mm diameter, and measures two orthogonal axes of shear simultaneously; this disc is mounted into an inlay that can be inserted into any stock orthopaedic shoe of the type commonly prescribed for diabetic foot problems. The transducer is located in the metatarsal head region of the inlay; exact placement of the transducer is determined by reference to the direct pressure distribution, the common method of palpation shown to be imprecise. Pilot trials on normal subjects are presented to evaluate the method.

Diabetic Neuropathies↗
PubMed1991

Technical evaluation of a CAD system for orthopaedic shoe-upper design.

Computer aided design is now employed routinely in the volume shoe trade. New styles are developed on a three-dimensional image of the last followed by automated pattern generation and engineering. It is suggested that such systems could be useful in the orthopaedic footwear industry although the different requirements for these bespoke products need careful consideration. A clinical trial has been conducted on the Shoemaster (Clarks Shoes) upper design system both to assess its technical capabilities and to consider its role in improvement of service and cosmetic appearance. This particular system works throughout on a three-dimensional representation of the shoe last, which offers particular advantages for integration with shape capture and reproduction. The report concentrates on the technical evaluation to assess (a) its ability to work with unusual last shapes dictated by medical requirements and (b) its potential for integration into a complete computer system for design of both shoe lasts and shoe uppers. The trial indicates that this particular system is promising in both respects.

Adult↗
PubMed1991

Clinical trial of a computer-aided system for orthopaedic shoe upper design.

A trial has been conducted to produce the uppers for orthopaedic shoes using an existing commercial computer-aided design system. The aims of the trial were to confirm that a CAD system developed for the volume shoe trade (Shoemaster from Clarks Shoes) could be used for the upper design of orthopaedic shoes and to assess the contribution of professional shoe design on cosmesis and acceptability of these shoes. A small number of adult diabetic patients and children with foot deformities were selected, all of who had previously been prescribed and issued with special shoes. The existing lasts for these patients were digitised, and new styles developed on the CAD system over a 3D image of the last. Pattern pieces were cut automatically and the uppers closed. Lasting was done as normal at the two collaborating orthopaedic companies and the shoes supplied to the patients. The CAD system proved successful in coping with orthopaedic last shapes and shoe requirements. Professional design produced fashionable and cosmetically-pleasing styles within the constraints imposed by the underlying medical conditions.

Adolescent↗
PubMed1989

Effect of hepatic vagotomy on postexercise substrate levels in food-restricted rats.

The metabolic effects of a selective hepatic vagotomy (HV) were investigated at rest and immediately after a 50-min exercise period (26 m/min, 0% grade) in rats subjected to an overnight 50% food restriction. This dietary restriction reduced liver glycogen content to 50% of normal resting concentrations (2.2-2.8 g/100 g). No significant differences between HV and sham-operated rats were found in resting and exercising beta-hydroxybutyrate, glucose, glycerol, and insulin concentrations. Postexercise liver glycogen concentrations were reduced to approximately 1.0 g/100 g in both HV and sham-operated groups. This decrease was associated with significantly (P less than 0.01) lower postexercise glycogen levels in the soleus muscle of HV rats (2.6 times) along with higher plasma free fatty acid concentrations (P less than 0.01). These data provide evidence that HV combined with a progressive decrease in liver glycogen content may influence substrate regulation during exercise. They also support the concept of the existence of hepatic glucoreceptors responsive to a decrease in liver glycogen content.

Animals↗
PubMed1988

Allergy to castor bean. II. Identification of the major allergens in castor bean seeds.

Castor bean proteins were separated and identified by isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis and blotted onto nitrocellulose paper. The capacity of the castor bean proteins to bind human IgE was probed with sera from castor bean-sensitive patients and radiolabeled anti-IgE. It proved difficult to identify allergens with isoelectric focusing. However, three allergens were identified when proteins were first separated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis: the 2S storage albumin, the 11S crystalloid proteins, and a third protein doublet with molecular weights of 47 and 51 kd. Specific IgE antibody to the 2S storage albumin, measured by RAST, was detected in most (96%) castor bean-sensitive patients, confirming it as the major allergen. We would like to suggest that the 2S albumin be named Ric c I, that the crystalloid proteins be named Ric c II, and that the 47/51 kd doublet be named allergen 3.

Allergens↗
PubMed1988

Issues and themes in computer aided design for external prosthetics and orthotics.

Computer aided design systems are finding use in prosthetics and orthotics in the production of customized components to match to and support body segments. Such systems consist essentially at present of shape measurement, computer manipulation of shape, and manufacture of the support surface or its mould. General themes of design philosophy, relationship of shape and pressure for body segments, representation and presentation of shape information by computer, surface adjustments, measurements and manufacturing geometry are considered. Aspects of existing systems are presented to highlight issues which may be the subject of future developments.

Computer Graphics↗
PubMed1988

Effect of selective hepatic vagotomy on plasma FFA levels in resting and exercising rats.

Metabolic effects of a selective hepatic vagotomy (HV) were investigated in nonfasted (N) and 24-h fasted (F) rats, at rest and immediately after a 50-min exercise period (26 m/min, 0% grade). In nonfasted rats, no significant differences between HV and sham-operated (SHM) groups were found in blood substrates [free fatty acids (FFA) or glucose], insulin, and muscle glycogen levels, either at rest or after exercise. In F rats, liver glycogen was almost completely depleted at rest. This depletion was associated with a significantly (P less than 0.05) lower plasma FFA concentration at rest in HV compared with SHM rats (mean +/- SE, 0.57 +/- 0.04 vs. 0.83 +/- 0.1 mmol/l). No differences in FFA levels were observed between the same two groups after the exercise period. Exercise, however, resulted in a 2.5 times greater glycogen breakdown in the soleus muscle of HV compared with SHM rats. Hepatic vagotomy in the F condition was also associated with lower resting and exercising insulin concentrations. It is concluded that HV, when followed by a 24-h fast, may influence metabolic substrate regulation at rest and to a certain extent during exercise. These data support the concept of the existence of hepatic glucoreceptors responsive to a decrease in liver glycogen content.

Animals↗
PubMed1986

Foot pressure measurement: a review of clinical findings.

In this review, a description of what is known about plantar pressure distribution in standing and in gait is followed by sections on clinical findings. Two major clinical areas are treated extensively, namely the diabetic foot and the foot in rheumatoid arthritis. Other applications, including the assessment of surgical procedures for orthopaedic corrections are also included. A large variety of different techniques for foot pressure measurement have been used; interpretation of the results has to be made on the basis of a firm understanding of the technique employed. Often, quantitative results from different pieces of apparatus are difficult to compare, indicating a need for accurate calibration and a standardized presentation. An up-to-date summary of pressure measurement systems reported over the past five years is included.

Arthritis, Rheumatoid↗
PubMed1986

Bouncy knee in a semi-automatic knee lock prosthesis.

The Bouncy Knee concept has previously proved of value when fitted to stabilised knee units of active amputees. The stance phase flex-extend action afforded by a Bouncy Knee increased the symmetry of gait and also gave better tolerance to slopes and uneven ground. A bouncy function has now been incorporated into a knee of the semi-automatic knee lock design in a pilot laboratory trial involving six patients. These less active patients did not show consistent changes in symmetry of gait, but demonstrated an improved ability to walk on slopes and increased their walking range. Subjective response was positive, as noted in the previous trials.

Artificial Limbs↗
PubMed1984

Foot loading in amputee stance.

A survey has been carried out to establish information on foot loading in amputee stance. The parameters measured are percentage body weight and the positions of the centres of pressure under each foot. The data was collected in a clinical environment by the use of a Double Video Forceplate (DVF), a tool developed at the Bioengineering Centre. The objective of the survey is to provide background information for the use of the DVF in static alignment of lower-limb prostheses. Results are presented from a number of patients attending the Roehampton Walking Training School, and for a small group of patients attending the Bioengineering Centre for delivery of an experimental below-knee prosthesis. Scattergrams and averaged results provide normative data which can assist in interpretation of DVF displays during individual alignment.

Adolescent↗
PubMed1980

Pedobarographic study of gait.

The use of a pedobarograph for gait studies offer a rapid method to obtain instantaneous, two-dimensional images of foot-loading, which can be made available immediately to the clinician for qualitative inspection. The system can also produce quantitative results with a dynamic bandwidth sufficient for the study of most features of load transference. Although the linearity and resolution of force level may be inferior to that obtained by other methods, the spatial resolution is superior.

Data Display↗