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Biomedical subjects

M Binns

Publications and source records attributed to M Binns.

16 recordsLinked to original sources

Assessment of the deformation of the Bateman bipolar hip prosthesis inner bearing due to moisture absorption and creep.

The mechanism of inner bearing stiffness of bipolar hip prostheses has been investigated. The Ultra-high Molecular Weight Polyethylene (UHMWPE) component of the Bateman bipolar hip prosthesis has been subjected to a series of static and dynamic tests to assess water absorption and creep. Although deformation of the UHMWPE occurred, this did not produce an increased resistance to movement in the inner bearing.

Biomechanical Phenomena

Neovascularisation of the epiphysis.

Two experiments in the rabbit model have been carried out to see if a vascular pedicle placed in a growing epiphysis would establish new capillaries. In one, the vascular pedicle of peroneus longus muscle was placed in the proximal fibula epiphysis. In the other, the proximal fibula was excised and the epiphysis placed across the saphenous artery and vein in the groin. After 3 months, histological examination of the epiphyses in both experiments showed that no new vessels had grown from the vascular pedicle. Cartilage is known to inhibit vascularisation, and these results suggest that attempts to revascularise the epiphysis, for example, following Perthes' disease, may fail. For the same reason, attempting to supplement the epiphyseal vessels by implanting a new vessel before or after epiphyseal transfer may fail.

Animals

A 39,000 Mr immunodominant protein of fowlpox virus contains multiple copies of a 12 amino acid repeat sequence.

The nucleotide sequence of an unusual fowlpox virus gene which maps immediately upstream from the fowlpox virus 4b gene has been determined. The 34,000 Mr protein predicted to be encoded by the gene contains 11 copies of a 12 amino acid serine-rich repeat sequence. The seven amino-terminal copies of the repeat sequence are perfectly conserved but variation exists in the four carboxy-terminal copies. Three peptides were synthesized which contained either one copy of the repeat sequence, two copies of the repeat sequence or a hydrophilic amino-terminal region of the protein. All three peptides when injected with adjuvant into rabbits gave rise to antibodies which reacted strongly on Western blots of purified fowlpox virus proteins with a 39,000 Mr protein. When directly compared in Western blots the antipeptide sera were shown to recognize a protein comigrating with one of the two immunodominant proteins recognized by chicken anti-fowlpox virus sera taken 2 weeks post-infection. The virion protein is removed by treatment with sodium deoxycholate suggesting that it is located at or near the surface of the virus.

Amino Acid Sequence

Femoral vein occlusion during hip arthroplasty.

The mechanism of femoral vein occlusion when the hip joint is dislocated and manipulated during arthroplasty has been studied in fresh anatomic specimens. Flow studies show that moderate degrees of flexion and adduction in association with dislocation obstruct venous flow just distal to the femoral sheath at normal pressures and flow rates. Internal femoral rotation during a posterior approach to the hip causes "scissoring" of the femoral vein between femur and pubic bone. External femoral rotation during an anterior approach does not occlude flow. Injection of Batson's acrylic and neoprene latex showed that obstruction is also due to about 4 cm of shortening caused by proximal migration of the femur after dislocation in association with adduction and flexion. The femoral vein in the unsupported segment distal to the femoral sheath subsequently buckles and kinks. During operative manipulation, intermittent obstruction at this level is therefore likely to cause intermittent venous distension distally. This mechanism depletes the femoral vein of fibrinolytic activity distal to the occlusion and may explain the incidence of deep femoral thrombosis peculiar to this procedure.

Femoral Vein

Stiffness of bipolar hip prostheses.

Following the removal of a Bateman bipolar hip arthroplasty for displaced intracapsular fracture, the inner bearing was found to be stiff. After dismantling the acetabular component, high density polyethylene (HDP) debris was found in the inner bearing in association with wear and distortion of the HDP and fibrous tissue. To explore the hypothesis that movement does not occur at the inner bearing of bipolar prostheses because of absent lubrication, a mechanical model of the hip joint was devised incorporating a Hastings bipolar arthroplasty. The dynamic frictional forces at the inner bearing were found not to be significantly reduced when the joint was lubricated with either synovial or serosanguinous fluid. It is suggested that if the initial range of movement of the inner bearing is reduced because of debris, then loads are concentrated by the femoral component on a smaller area of the acetabular HDP component. This leads to increased shear forces, creep and distortion of the HDP, which further contributes to inner bearing stiffness.

Hip Joint

A toe retractor.

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Humans

Anatomy of the 'venous foot pump'.

The gross anatomy of the deep plantar veins has been examined in 14 cadaveric feet in order to assess their function as a 'venous foot pump'. The lateral plantar vein was found to be larger than the medial and is double in its proximal segment. Both plantar veins contain valves which face proximally and have a convoluted and intermuscular course. These features suggest that the deep plantar veins act as a pump that empties during contraction of the intrinsic foot muscles during the stance phase of gait.

Foot

Sequence analysis of an 11.2 kilobase, near-terminal, BamHI fragment of fowlpox virus.

The nucleotide sequence of an 11.2 kilobase fragment of the fowlpox virus genome is presented. The fragment comes from near one end of the genome and contains part of the terminal inverted repeat. Twenty open reading frames (ORFs) are predicted from the sequence and are classified into 13 major and seven minor ORFs. The 100 base pairs immediately upstream of each ORF are up to 83% AT-rich, with some motifs similar to those seen in vaccinia virus early gene promoters. The TTTTTNT element which has been identified as a termination signal for vaccinia virus early genes is also found downstream of several ORFs. Three ORFs are predicted to specify polypeptides with significant homology to proteins coded by genes near termini of orthopoxvirus genomes: the vaccinia virus 42K early gene and 32.5K host range gene, and the cowpox virus 38K red pock gene. In addition, there are two families of ORFs within the fragment which potentially encode related polypeptides. One of these, family B, contains three ORFs which are related to those of chicken and rat hepatic lectins.

Amino Acid Sequence

Joint laxity in idiopathic adolescent scoliosis.

Joint laxity was quantified by measuring the distance from the thumb tip to the forearm during passive apposition in 500 normal Southern Chinese women. Joint laxity was found to have a normal distribution throughout the population and to decrease with age. When 109 Chinese girls with idiopathic adolescent scoliosis were similarly tested they were found to have significantly more laxity, suggesting that the two conditions are associated.

Adolescent

Development of a taxonomy of therapist difficulties: initial report.

While psychotherapists discuss amongst themselves and in supervision the struggles they experience face-to-face with their patients, empirical study of therapists' experience of psychotherapy has been scant and there has been little investigation of therapists' difficulties. We require tools for such investigation and in this initial report we describe the development of a taxonomy of situations that psychotherapists experience as difficult and indicate lines of research to which the taxonomy might be applied. We also suggest that our procedure might serve as a model of collective self-study for other groups of practitioner-researchers. Using accounts of our own difficulties as therapists, we constructed a consensual set of experimental categories that could be applied to describe them. These were designated as Therapist (T)-Incompetent, T-Damaging, T-Puzzled, T-Threatened, T-Out of Rapport, T's Personal Issues, Painful Reality/T's Ethical Dilemma (a combined category), T-Stuck, and T-Thwarted. We then employed a fresh set of 30 accounts, which were also drawn from our own experience but had not contributed to the development of the taxonomy, to study the taxonomy's reliability. Each of us rated the presence and predominance of the categories for each of the 30 accounts. Both presence and predominance of all nine categories in the taxonomy could be reliably identified, with about three raters required to ensure good reliability for all categories; alphas (for our group of seven raters) were in the range 0.88-0.95 for presence-absence and 0.83-0.94 for predominance. We conclude that the taxonomy is a serviceable tool for further investigation. We also show that we are discriminable from one another as therapists in terms of the kinds of difficulty we reported, differences amongst us conforming to what we know of one another's therapeutic practice. We note implications for the diagnostic use of the taxonomy in training and supervision.

Clinical Competence

Analysis of the camelpox virus thymidine kinase gene.

The thymidine kinase (TK) gene from camelpox virus has been cloned using the polymerase chain reaction (PCR). The oligonucleotides used in the PCR amplification were based on residues conserved amongst the orthopoxviruses on the 5' and 3' sides of the TK gene. The oligonucleotides were also designed to contain HindIII cleavage sites to facilitate subsequent cloning. A fragment of approximately 700 base pairs was amplified from camelpox virus infected tissue culture cells. This fragment was then cleaved with HindIII and cloned into the M13mp19 sequencing vector which had also been cut with HindIII. The nucleotide sequence of the TK gene was then determined and compared to other poxvirus TK sequences. The possibilities of producing TK- camelpox virus vaccines and of using camelpox virus as a vaccine vector for the expression of genes from other camel pathogens are discussed.

Amino Acid Sequence