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Biomedical subjects

K Willett

Publications and source records attributed to K Willett.

At least 19 recordsLinked to original sources
PubMed2006

Outcome of surgery for reconstruction of fractures of the acetabulum. The time dependent effect of delay.

This is a retrospective case review of 237 patients with displaced fractures of the acetabulum presenting over a ten-year period, with a minimum follow-up of two years, who were studied to test the hypothesis that the time to surgery was predictive of radiological and functional outcome and varied with the pattern of fracture. Patients were divided into two groups based on the fracture pattern: elementary or associated. The time to surgery was analysed as both a continuous and a categorical variable. The primary outcome measures were the quality of reduction and functional outcome. Logistic regression analysis was used to test our hypothesis, while controlling for potential confounding variables. For elementary fractures, an increase in the time to surgery of one day reduced the odds of an excellent/good functional result by 15% (p = 0.001) and of an anatomical reduction by 18% (p = 0.0001). For associated fractures, the odds of obtaining an excellent/good result were reduced by 19% (p = 0.0001) and an anatomical reduction by 18% (p = 0.0001) per day. When time was measured as a categorical variable, an anatomical reduction was more likely if surgery was performed within 15 days (elementary) and five days (associated). An excellent/good functional outcome was more likely when surgery was performed within 15 days (elementary) and ten days (associated). The time to surgery is a significant predictor of radiological and functional outcome for both elementary and associated displaced fractures of the acetabulum. The organisation of regional trauma services must be capable of satisfying these time-dependent requirements to achieve optimal patient outcomes.

Acetabulum↗
PubMed2005

The MRI diagnosis and management of incomplete intertrochanteric fractures of the femur.

Incomplete intertrochanteric fractures do not extend across to the medial femoral cortex and are stable, without rotational deformity or shortening of the lower limb. The aim of our study was to establish whether they can be successfully managed conservatively. A total of 68 patients over a five-year period presented with a suspected fracture of the femoral neck and underwent an MRI scan for further assessment. From these, we retrospectively reviewed eight patients with normal plain radiographs but with an incomplete, intertrochanteric fracture on MRI scan. Five were managed conservatively and three operatively. The mean length of hospital stay was 16 days for the conservatively-treated group and 15 days for those who underwent surgery; this was not statistically significant (p > 0.5) and all patients were mobilised on discharge. Although five patients were readmitted at a mean of 3.2 years after discharge, none had progressed to a complete fracture. We believe that patients with incomplete intertrochanteric fractures should be considered for conservative treatment.

Aged↗
PubMed2000

Femoral nailing for metastatic disease of the femur: a comparison of reamed and unreamed femoral nailing.

A total of 73 consecutive intramedullary femoral nails were inserted for metastatic disease of the femur; 43 were reamed and 30 were solid nails. The two groups were similar with regards to age, type of primary tumour, anatomical site, acute or 'impending' fracture and postoperative survival. The 'solid' nail offers a satisfactory alternative form of stabilisation for metastatic disease of the femur with rates of implant failure which are comparable with the reamed nail. In this series bilateral nailing was not associated with any increase in mortality. Contrary to other reports, imposing a delay in patients with pain and a short life expectancy seems unjustified. The use of the 'solid' femoral nail does not prevent sudden death due to massive fat embolism.

Adolescent↗
PubMed2000

The use of interlocked 'customised' blade plates in the treatment of metaphyseal fractures in patients with poor bone stock.

Balanced and stable fixation in metaphyseal fractures and nonunion can be difficult because of osteoporosis, disuse osteopenia, comminution, joint proximity or malignant infiltration. Five patients with nonunion and four with comminuted or pathological acute fractures of metaphyseal areas of the tibia or humerus were treated with a 'customized' interlocked blade plate. The plates are standard AO dynamic compression plates of a suitable length that are bent to an acute angle in an industrial vice and 'interlocked'. The nine patients with a mean age of 62.2 years (range 30-91) were followed up for a mean of 7.2 months. At follow-up all fractures had healed with a single complication of subacromial impingement in a patient with a proximal humeral fracture.

Adult↗
PubMed2000

An evaluation of the effectiveness of the Injury Minimization Programme for Schools (IMPS).

OBJECTIVE: To evaluate the effect of an injury prevention programme (Injury Minimization Programme for Schools, IMPS) on children's primary and secondary prevention, and basic life support, knowledge, attitudes, skills, and behaviour. DESIGN: Prospective non-randomised matched control. SETTING: Radcliffe NHS Trust and primary and middle schools in Oxfordshire, UK. SUBJECTS: 1,200 year 6 children (10 and 11 years old); 600 received IMPS, a primary and secondary injury prevention programme taught in the school and hospital environments; 600 children in the control group received no planned intervention. MAIN OUTCOME MEASURES: Safety knowledge, measured using a quiz. Resuscitation skills and behaviour observed and assessed using a simulated emergency scenario. Attitude and hypothetical behaviour towards safety assessed by the "draw and write" technique. RESULTS: Before intervention, both groups had similar levels of knowledge. Five months after the intervention, significantly more IMPS trained children demonstrated a greater increase in knowledge in administering first aid and the correct procedure for making a call to the emergency services. They also demonstrated better basic life support techniques-for example, mouth-to-mouth and cardiac compressions. They identified more subtle dangers, were more likely to seek help, and tell others that their behaviour was dangerous. CONCLUSION: The results demonstrate the benefits of the IMPS programme on injury prevention knowledge, attitudes, and behaviours.

Accident Prevention↗
PubMed1998

'Clearance' of cervical spine injury in the obtunded patient.

The need to exclude cervical spine injury ('clearance') in an obtunded patient poses a dilemma. The purpose of this study was to find out the current practices for tackling this situation around the country. A questionnaire was sent to all Intensive Care Units who accept injured patients. There is a great diversity in the management and investigation of these patients. There is clearly a need for a recognised protocol for dealing with this difficult situation. Such a protocol is suggested.

Cervical Vertebrae↗
PubMed1997

Studies on the relationship between estrogen receptor content, glutathione S-transferase pi expression, and induction by 2,3,7,8-tetrachlorodibenzo-p-dioxin and drug resistance in human breast cancer cells.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) induces both phase I and phase II drug-metabolizing enzymes in rodent liver and hepatoma cell lines and this induction is mediated by the aryl hydrocarbon (Ah) receptor. Induction of CYP1A1 by TCDD in human breast cancer cells has been reported and results of several studies suggest that the estrogen receptor (ER) may be required for Ah responsiveness. This study investigates the induction of GST pi by TCDD in human breast cancer cells and the role of the ER in mediating this response. TCDD did not induce chloramphenicol acetyl transferase (CAT) activity in ER positive (ER+) MCF-7 and ER- MDA-MB-468 and MDA-MB-231 human breast cancer cell lines transiently transfected with GST pi (human) or GSTP (rat) promoter-reporter constructs containing the -291/+36 and -2.9/+59 region, respectively, of the GST pi and GSTP gene promoters. Furthermore, TCDD did not induce GST pi or GSTP in MDA-MB-468 and MDA-MB-231 human breast cancer cells stably transfected with the ER. RT-PCR confirmed that GST pi mRNA levels were low in ER+ MCF-7 cells and high in ER- MDA-MB-468 and MDA-MB-231 cells; however, in MDA-MB-468 and MDA-MB-231 cells stably transfected with the ER GST pi mRNA levels remained elevated and were not inducible. MDA-MB-468 and MDA-MB-231 cells stably transfected with the ER exhibited increased GST activity and decreased GSH content compared to wild-type cells; however, in MDA-MB-468 cells stably transfected with ER, the susceptibility to doxorubicin, ellipticine, chlorambucil, malphalan, or cisplatin was similar to that observed in wild-type cells. Adriamycin accumulation was similar in wild-type and ER stably transfected cells and verapamil did not affect this response, suggesting that ER expression did not influence p-glycoprotein activity. Taken together these data suggest that not all GST isoforms are responsive to TCDD and stable transfection of ER- cells with ER is not sufficient to restore the ER+ phenotype in some breast cancer cell lines.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Estrogen does not inhibit 2,3,7, 8-tetrachlorodibenzo-p-dioxin-mediated effects in MCF-7 and Hepa 1c1c7 cells.

The estrogen receptor and aryl hydrocarbon receptor (AhR) are coexpressed in several Ah and estrogen-responsive human breast cancer cell lines. However, a recent study reported that 17beta-estradiol (E2) inhibited Ah responsiveness in mouse Hepa 1c1c7 hepatoma cells (Kharat, I., and Saatcioglu, F. (1996) J. Biol. Chem. 271, 10533-10537), and therefore, estrogen receptor-AhR cross-talk was reinvestigated in MCF-7 and mouse Hepa 1c1c7 cells. Treatment of MCF-7 or Hepa 1c1c7 cells with 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD) resulted in induction of CYP1A1-dependent activity and mRNA levels. Treatment of both cell lines with E2 had no effect on basal or TCDD-inducible CYP1A1-dependent activity or mRNA levels. In MCF-7 and Hepa 1c1c7 cells transiently transfected with an Ah-responsive plasmid containing the 5'-regulatory region of the human CYP1A1 gene fused to the chloramphenicol acetyltransferase reporter gene 10 nM TCDD significantly induced chloramphenicol acetyltransferase activity; in cells cotreated with TCDD plus E2 the induced response was not affected by the hormone. Nuclear extracts from cells treated with dimethyl sulfoxide, E2, TCDD, and TCDD plus E2 were incubated with the [32P]dioxin-responsive element and analyzed by gel electrophoretic mobility shift assays. A retarded band associated with formation of a [32P]dioxin-responsive element-AhR complex was observed in nuclear extracts from cells treated with TCDD or TCDD plus E2 (cotreated). Collectively these studies suggest that E2 does not modulate AhR-mediated CYP1A1 gene expression in MCF-7 or Hepa 1c1c7 cells.

Animals↗
PubMed1995

Characterization of vertebral strength using digital radiographic analysis of bone structure.

Bone mineral densitometry (BMD) is useful in predicting fracture risk, but, unfortunately, there is a significant degree of overlap in BMD measurements of patients who have a high risk of fracture and patients with a low risk of fracture. In this study, a method of characterizing trabecular bone structure in digitized radiographs of vertebrae is proposed and assessed. A significant correlation between bone "structure" and the compressive strength of vertebral bodies was found. The utility of the parameter for distinguishing between "weak" and "strong" bone samples was assessed using receiver operating characteristic (ROC) analysis. Using this analysis, the structural parameter produced an area under the ROC of 0.88 +/- 0.05, while a bone density measure produced an area of 0.79 +/- 0.07. The results suggest that the addition of a measure of bone structure to the conventional measures of bone density may prove useful in predicting the quality of bone when considering surgical or medical intervention for osteoporotic conditions.

Bone Density↗
PubMed1995

Epidural anaesthesia and urinary dysfunction: the risks in total hip replacement.

Epidural anaesthesia in total hip replacement is an established and safe practice. It may be used alone or in combination with general anaesthesia for analgesia. Urethral catheterization in the perioperative period is known to greatly increase the complication of deep sepsis following total hip replacement. We assessed the effect on the incidence of urinary catheterization of using bupivocaine epidural anaesthesia in addition to general anaesthesia in total hip replacement. A prospective study was made of 113 total hip replacements. The incidence of catheterization in male patients who received an epidural was 67% compared to only 12% who had no epidural [P = 0.001]. In women the corresponding rates were 30% and 23%. We conclude that in men the use of supplementary epidural anaesthesia with bupivocaine is associated with a worrying increased need for urinary catheterization. This must be balanced against the claimed benefits of this form of anaesthesia.

Adult↗
PubMed1993

Transfer of multiply-injured patients for neurosurgical opinion: a study of the adequacy of assessment and resuscitation.

A total of 21 consecutive referrals with multiple injuries (Injury Severity Score (ISS) 17-66), admitted into the Regional Neurosurgical Unit (RNSU) over a 1-year period from August 1989, was analysed to evaluate the risks associated with transfer of such patients from district general hospitals within the North West Thames Region. Injury assessment was deficient in nine cases. Four developed hypovolaemic shock during transfer, and in five resuscitation was inadequate. Four had minor head injuries and two had no head injury; of these cases, one died. There were four fatalities: the mean ISS in this group was 42, and in all cases deficiencies in resuscitation and assessment before transfer were identified. There were seven major missed injuries. All patients had musculoskeletal injuries and 16 required orthopaedic intervention within 6 h. Interhospital transfer of this group of patients carries significant risks, may be unnecessary, and may delay other surgical priorities.

Craniocerebral Trauma↗
PubMed1993

Cerclage wiring in internal fixation of acetabular fractures.

In the last 100 fractures of the acetabulum surgically treated in our institution, cerclage wires have been used as a reduction tool in 14 patients. In each case the fracture pattern affected both columns, and nine of them were approached through a single ilioinguinal exposure. To evaluate our initial experience with the method, these patients were reviewed using medical records, operative notes, and radiological assessment to determine its indications and effectiveness. In each patient, using a limited further dissection, at least one cerclage wire was passed through the greater sciatic notch, embracing the proximal extent of a posterior column fragment. It was then tightened above the anterior-inferior iliac spine, achieving reduction. In 11 cases reduction was obtained to within 1 mm, and joint congruence with < 3 mm of residual displacement was obtained in 13 hips. This reduction was maintained until union, except in one case, where it was lost postsurgery. Cerclage wires may be used to successfully effect an indirect reduction of the posterior column from an anterior approach in fractures affecting both columns, where the posterior column fracture line is proximal. The technique may contribute to fracture stabilization, but supplementary fixation was added in 12 of our patients.

Acetabulum↗
PubMed1993

Biomechanical testing of a new design for Schanz pedicle screws.

Standard 5-mm AO Schanz pedicle screws were biomechanically compared with a new design, featuring 6-mm threads with a 5-mm core diameter continuous with the shaft. One each of the two screw designs was surgically inserted into the matching pedicles of 32 cadaveric vertebrae. The pull-out strengths of the screws were then determined by recording the peak force values during extraction under servohydraulic displacement control. The screws were also tested in three-point bending, varying the inner load point with respect to the shaft thread junction, within a clinically anticipated range. The mean pull-out strength for the 6-mm screw was 597 N, which was significantly greater than the mean strength of 405 N for the 5 mm screw (p = 0.002). The 6-mm screw was also stronger in three-point bending, and failed at the point of inner load application, with no evidence of a stress-raising effect at the shaft/thread junction. In contrast, the 5-mm screw withstood lower loads, and failed at the shaft/thread junction, regardless of the point of loading. Pedicle screw breakage and pull-out are the recognized modes of failure of spinal implants, which are dependent on pedicle screw fixation. The results suggest distinct biomechanical advantages for the 6-mm screw, which should be used whenever clinically feasible.

Absorptiometry, Photon↗
PubMed1979

Selenium and gamma-glutamyl transferase activity in the serum of thoroughbreds.

Selenium and gamma-glutamyl transferase activity has been measured in the serum of clinically health thoroughbreds. The thoroughbreds, whose performance was reported to be unsatisfactory, had consistently low concentrations of selenium and high activity of gamma-glutamyl transferase in the serum when compared with those whose performance was as expected. Vitamin E levels in the serum showed no such difference. The only other biochemical and haematological abnormality was lower serum phosphate concentrations in the unsatisfactory group. These results suggest that low concentrations of selenium in the serum may be associated with subclinical hepatic insufficiency in the thoroughbred.

Animals↗