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Biomedical subjects

D J Wilson

Publications and source records attributed to D J Wilson.

At least 55 records · Page 3Linked to original sources
PubMed2000

Radiological review of accident and emergency radiographs: a 1-year audit.

AIM: To assess the impact and cost effectiveness of a system of radiological review of accident and emergency (A&E) plain films. MATERIALS AND METHODS: Review documentation was studied retrospectively over a 1-year period. Six hundred and eighty-four actual or suspected errors in the initial radiological interpretation by A&E staff were highlighted by radiologists in training. These selected 'red reports' were then further reviewed by a musculoskeletal radiologist and a more senior member of the A&E team. RESULTS: Three hundred and fifty-one missed or strongly suspected fractures were detected, with ankle, finger and elbow lesions predominating. Other errors included 11 missed chest radiograph abnormalities and 24 A&E false-positives. Radiologists in training tended to over-report abnormalities with an 18% false-positive rate when compared to the subsequent musculoskeletal radiology opinion. Following review, further action was taken by A&E staff in 286 (42.6%) of cases. No operative intervention was required in those patients with a delayed or missed A&E diagnosis. Consideration is given to the cost of providing this form of review and the impact of medico-legal factors. CONCLUSION: Compared with the large numbers of patients seen and radiographed in a busy A&E department, the number of radiological errors was small. There were even fewer changes in management. Despite this, concern over litigation, clinical governance and future work patterns in A&E make this form of review a useful means of risk reduction in a teaching hospital.Williams, S. M. (2000). Clinical Radiology55, 861-865

Cost-Benefit Analysis↗
PubMed2000

Clinicopathologic correlation of fluorescein and indocyanine green angiography in exudative age-related macular degeneration.

PURPOSE: To correlate the clinical and histopathologic features of an eye with age-related macular degeneration studied with fluorescein (FA) and indocyanine green (ICG) angiography 4.5 months before the patient's death. METHODS: Histopathologic features from serial sections through the macula of a 76-year-old man with occult choroidal neovascularization (CNV) were reconstructed in a scaled two-dimensional map and compared with FA and ICG angiogram images obtained 4.5 months before his death. RESULTS: The region of prior laser photocoagulation was identified as a well-demarcated hypofluorescent region in the early frames of the FA and the early and late phases of the ICG angiogram. This corresponded histopathologically to a well-circumscribed area of absence of the choriocapillaris, loss of the outer retina and retinal pigment epithelium, and scarring of the choroid. Occult CNV characterized by elevated late hyperfluorescence on the FA and intense well-defined hyperfluorescence on the ICG angiogram corresponded to a thick fibrovascular membrane in the subretinal space and within Bruch's membrane. Thin extensions of both the subretinal and intra-Bruch's membrane fibrovascular membrane components corresponded to nonelevated stippled late hyperfluorescence on the FA and mild late hyperfluorescence on the ICG angiogram. CONCLUSION: Histopathologic mapping revealed a large fibrovascular complex located subretinally and within Bruch's membrane with thin and thick components that correlate well with findings of occult CNV on FA and ICG angiography.

Aged↗
PubMed2000

Fibrin scaffold as an effective vehicle for the delivery of acidic fibroblast growth factor (FGF-1).

The effect of wound healing by fibrin and acidic fibroblast growth factor (FGF-1) in an in vivo model was evaluated in this study. Four full-thickness wounds were made on the dorsum of each rabbit (n = 5). Each of these wounds had different treatment groups: control, topical FGF-1 (100 microg/9 cm2), fibrin (2.0 mL at 60 mg/mL fibrinogen), and FGF-1 (100 microg/9 cm2)/fibrin. The animals were sacrificed at the end of 2 weeks. Histomorphometric analysis and mechanical testing were conducted to assess the healing response. FGF-1/fibrin treatment improved the mechanical properties of the healed tissue. Fibrin scaffold exhibited the desired tissue response, as demonstrated by the lack of inflammation, and was deemed an effective carrier for FGF-1.

Animals↗
PubMed2000

Kinematics of the hind limb in trotting horses after induced lameness of the distal intertarsal and tarsometatarsal joints and intra-articular administration of anesthetic.

OBJECTIVE: To identify hind limb and pelvic kinematic variables that change in trotting horses after induced lameness of the distal intertarsal and tarsometatarsal joints and after subsequent intra-articular administration of anesthetic. ANIMALS: 8 clinically normal adult horses. PROCEDURE: Kinematic measurements were made before and after transient endotoxin-induced lameness of the distal intertarsal and tarsometatarsal joints and after intra-articular administration of anesthetic. Fourteen displacement and joint angle (metatarsophalangeal [fetlock] and tarsal joints) measurements were made on the right hind limb, sacrum, and the right and left tubera coxae. Kinematic measurements were compared by general linear models, using a repeated measures ANOVA. Post hoc multiple comparisons between treatments were evaluated with a Fisher least squared difference test at alpha = 0.05. RESULTS: After lameness induction, fetlock and tarsal joint extension during stance decreased, fetlock joint flexion and hoof height during swing increased, limb protraction decreased, and vertical excursion of the tubera coxae became more asymmetric. After intra-articular administration of anesthetic, limb protraction returned to the degree seen before lameness, and vertical excursion of the tubera coxae became more symmetric. CONCLUSIONS AND CLINICAL RELEVANCE: Increased length of hind limb protraction and symmetry of tubera coxae vertical excursion are sensitive indicators of improvement in tarsal joint lameness. When evaluating changes in tarsal joint lameness, evaluating the horse from the side (to assess limb protraction) is as important as evaluating from the rear (to assess pelvic symmetry).

Anesthetics↗
PubMed2000

Changes in kinematic variables observed during pressure-induced forelimb lameness in adult horses trotting on a treadmill.

OBJECTIVE: To determine whether kinematic changes induced by heel pressure in horses differ from those induced by toe pressure. ANIMALS: 10 adult Quarter Horses. PROCEDURE: A shoe that applied pressure on the cuneus ungulae (frog) or on the toe was used. Kinematic analyses were performed before and after 2 levels of frog pressure and after 1 level of toe pressure. Values for stride displacement and time and joint angles were determined from horses trotting on a treadmill. RESULTS: The first level of frog pressure caused decreases in metacarpophalangeal (fetlock) joint extension during stance and increases in head vertical movement and asymmetry. The second level of frog pressure caused these changes but also caused decreases in stride duration and carpal joint extension during stance as well as increases in relative stance duration. Toe pressure caused changes in these same variables but also caused maximum extension of the fetlock joint to occur before midstance, maximum hoof height to be closer to midswing, and forelimb protraction to increase. CONCLUSION AND CLINICAL RELEVANCE: Decreased fetlock joint extension during stance and increased head vertical movement and asymmetry are sensitive indicators of forelimb lameness. Decreased stride duration, increased relative stance duration, and decreased carpal joint extension during stance are general but insensitive indicators of forelimb lameness. Increased forelimb protraction, hoof flight pattern with maximum hoof height near midswing, and maximum fetlock joint extension in cranial stance may be specific indicators of lameness in the toe region. Observation of forelimb movement may enable clinicians to differentiate lameness of the heel from lameness of the toe.

Animals↗
PubMed2000

Evaluation of an experimental milking pulsation system for effects on milking and udder health.

This study was to test whether cows milked by an experimental pulsation method differed from cows milked with conventional pulsation milking in somatic cell count (SCC), intramammary infections (IMI) defined by milk bacteriological culture results, teat end condition, or milk flow rate. The study design was a 1-yr trial with a completely randomized block crossover. Holstein cows were blocked into 15 pairs of contemporaries. Both cows from each pair were milked with experimental pulsation and with conventional pulsation for 6 mo, in reverse order from each other. The SCC (217,000/ml) of experimentally milked cows was not significantly different from SCC of conventionally milked cows (175,000/ml). Mean milk flow rate was 5.2 lb/min (2.4 kg/min) for experimentally milked cows and 5.3 lb/min (2.4 kg/min) for conventionally milked cows, not significantly different. Differences among the experimentally and conventionally milked cows, respectively, in new (13.5 and 12.7%), chronic (12.9 and 8.9%), and negative (73.6 and 78.4%) quarter culture results were not significant. New IMI per 100 d of lactation were 1.50 and 1.46, and chronic IMI per 100 d were 1.85 and 1.27, for experimentally and conventionally milked cows, respectively. These IMI rates were not significantly different between pulsation types. There were more new Staphylococcus aureus IMI associated with conventional pulsation, but overall cases of Staph. aureus were similar between the two types of pulsation. Teat end scores for the experimentally and conventionally milked cows, respectively, were good (6.5 and 11.7%), intermediate (68.2 and 66.9%), and poor (25.3 and 21.4%), not significantly different. These results support previous studies, which have found that except for complete failure of pulsation, differences in pulsation characteristics apparently have little effect on milking and udder health.

Animals↗
PubMed2000

Left ventricular diastolic dysfunction in patients with hypertension and preserved systolic function.

OBJECTIVE: To assess prospectively diastolic function in hypertensive patients with preserved left ventricular function, particularly focusing on the limitation of the transmitral flow velocity curve alone to detect diastolic dysfunction. PATIENTS AND METHODS: Comprehensive Doppler analysis was performed in 51 hypertensive patients with preserved left ventricular systolic function. RESULTS: The ratio of the peak early diastolic filling wave velocity to the peak velocity of filling wave at atrial contraction was less than the age-adjusted mean value minus 2 SD in 16 patients, and the other 35 patients had a "normal" transmitral Doppler signal. However, the combined transmitral and pulmonary venous Doppler analysis revealed that 12 of these 35 patients had a "pseudonormal" pattern. The prevalence of diastolic dysfunction was estimated at 31% with use of transmitral Doppler alone but increased to 55% when comprehensive Doppler analysis was used (P < .05). CONCLUSION: The presence of diastolic dysfunction has been frequently overlooked in hypertensive patients with transmitral Doppler analysis alone, and an assessment of diastolic function with a comprehensive Doppler analysis is needed in patients at risk for diastolic dysfunction.

Aged↗
PubMed1999

MEK1 activation rescues Jurkat T cells from Fas-induced apoptosis.

Although the protease cascade initiated by Fas (CD95, Apo-1) is well characterized, there remains little known about how kinase pathways may impact on Fas-mediated apoptosis. We recently observed that in T lymphocytes Fas strongly induced activation of JNK (c-Jun N-terminal kinase) but not of second messengers leading to activation of ERK (extracellular regulated kinase). Additionally, Fas-mediated apoptosis was significantly inhibited with PMA, a potent activator of the ERK signaling pathway. This suggested a model whereby activation of the ERK pathway might attenuate Fas-mediated apoptosis. This was confirmed in the current study by showing that activation of MEK1, the upstream regulator of ERK, reduces Fas-mediated apoptosis, whereas inhibition of MEK1 augments apoptosis by Fas. Furthermore, Fas-mediated apoptosis of Jurkat T cells is not affected by constitutively active or dominant negative variants that modulate the JNK pathway. These results demonstrate that Fas-induced JNK activation is not required for apoptosis by Jurkat T cells, but rather is more likely secondary to cell stress during the early phases of apoptosis. This is supported by the ability of the caspase blocker zVAD to inhibit both apoptosis and JNK activation by Fas.

Annexin A5↗
PubMed1999

Response to local anaesthetic injection as a predictor of successful hip surgery.

AIM: To compare the outcome of hip therapy with the response to local anaesthetic into the hip. MATERIALS AND METHODS: A retrospective hip arthrographic study of 60 patients complaining of hip pain was performed. The average age of the patients was 58 +/- 20 years with ratio of men to women of 11:19. Thirty-eight of these patients underwent local anaesthetic intracapsular injection. Twenty-three (61%) obtained relief from pain whereas two (5%) experienced worsened pain. RESULTS: Of the 23 patients who experienced pain relief 17 (74%) had a positive post-operative course, in comparison with eight (44%) who had a positive post-operative course from the group where intra-articular local anaesthetic was not used. It was also noted that patients over 30 years of age had favourable post-operative results in the presence or absence of local anaesthetic testing. CONCLUSION: These results indicate that hip arthrography with a pain relieving intracapsular local anaesthetic injection, is a positive post-operative prognostic factor in a patient group of disparate disorders. A positive response to local anaesthetic injection into a hip may predict which patients are likely to respond well to surgery. We advise alterations to the consent procedure to add a warning concerning the small risk of increased hip pain. If further studies were to confirm our results it may be wise to recommend that local anaesthetic intracapsular injection and judgement of its efficacy should precede many surgical procedures involving the hip.

Adolescent↗
PubMed1999

Work problems and accommodations reported by persons who are postpolio or have a spinal cord injury.

A number of studies have documented early functional declines in persons with a disability. The purpose of this study was to document (1) whether employees who are aging with their disability have experienced new work problems as a consequence of functional declines and (2) whether their work problems are being accommodated adequately. Ninety-six individuals with a disability (50 who are postpolio and 46 who had a spinal cord injury) were interviewed by phone. Each had worked at least 5 years postonset and was either currently working or unemployed for less than 5 years at the time of the interview. Forty-nine of the 50 persons who are postpolio reported they had experienced functional declines in recent years, and 41 of the 50 rated the severity of their disability greater than it was when they first began working. As a result of the functional declines they had experienced, most (90.9%) of their work problems were new and would not have been significant problems for them when they first began working. The situation was very different for the group with spinal cord injuries. Only a few members of that group had experienced functional declines that were causing new problems at work. A total of 480 work problems were reported by study participants. Three out of every eight problems did not have an accommodation satisfactory to the employee. The primary reason why a satisfactory solution was not provided was that no accommodation had been identified. Employers were generally supportive of the employee's need for accommodation; they paid for 59.1% of the accommodations that had a cost and refused to provide an accommodation for only 18 of the 480 problems.

Activities of Daily Living↗
PubMed1999

Evaluation of prior photorefractive keratectomy in donor tissue.

PURPOSE: To describe a case in which an eye donor had prior bilateral photorefractive keratectomies and to elucidate possible methods of evaluation and screening of donor tissue. METHODS: Case report. A 62-year-old eye donor was reported to have received radial keratotomy before his death. Further investigation by the eye bank showed a history of photorefractive keratectomy (PRK), not radial keratotomy. The corneas were therefore not used for transplantation, and the eyes were evaluated by slit-lamp examination, photography, corneal topography, and histology. RESULTS: Slit-lamp and photographic examination did not indicate the presence of PRK ablations. Corneal topography mapping with the TMS-1 was relatively ambiguous for identifying PRK flattening, while multiple data formatting of the cornea with the Orbscan resulted in the strongest suggestion of prior PRK. Histologic analysis showed central corneal thinning and loss of Bowman's membrane consistent with PRK. CONCLUSIONS: In the absence of a positive donor history for PRK, current methods of screening donor tissue for prior PRK often are insufficient to exclude these corneas from use in transplantation. More refined placido imagery corneal topography or newer technologies such as the Orbscan may allow more sensitive and specific methods of donor tissue screening.

Contraindications↗
PubMed1999

Comparison of seven antibiotic treatments with no treatment for bacteriological efficacy against bovine mastitis pathogens.

Milk culture results were retrospectively reviewed from 9007 cases of subclinical mastitis affecting cows housed in dairy herds located in New York and northern Pennsylvania. Cases included in this analysis had at least one mastitis pathogen isolated from the initial milk sample, were recultured within 1 mo, had permanent cow identification, and had records of whether mastitis was treated with an antibiotic or no treatment at all. Overall bacteriological cure rate for 21 mastitis pathogens was 68% (6097 of 9007). Antibiotic treated cases had a higher cure rate (75%) than did untreated cases (65%). Antibiotic treatments that significantly differed from the untreated cure rate of 65% were amoxicillin (82%), erythromycin (76%), cloxacillin (73%), and pirlimycin (44%). Cure rates for antibiotic treatments with cephapirin, hetacillin, or penicillin did not differ from the untreated cure rate. Agents for which some antibiotics were associated with increased cure rates compared with no treatment were Streptococcus agalactiae, streptococci other than Strep. agalactiae, and coagulase-negative staphylococci. The antibiotic most commonly associated with higher cure rates was amoxicillin. Most of the 21 mastitis agents showed no difference in bacteriologic cure rates between any of the 7 antibiotic treatments and no treatment.

Amoxicillin↗
PubMed1999

Accuracy of digitization using automated and manual methods.

BACKGROUND AND PURPOSE: Computerized 3-dimensional (3-D) motion measurement systems are used by those interested in human motion. The purposes of this study were (1) to determine the limits of accuracy in determining intersegmental angles during pendular motion at varying speeds and (2) to determine changes in accuracy introduced by autodigitization and digitization by experienced manual raters. METHODS: Angular speed of a T-shaped pendulum was systematically increased by releasing the pendulum from 4 angles (0 degrees [no movement], 45 degrees, 90 degrees, and 120 degrees). Twelve reference angles calculated from markers placed on the pendulum were estimated over 20 frames for 10 trials at each release position. RESULTS: Mean errors across trials and frames for intersegmental angles reconstructed by a 3-D motion measurement system were within +/- 1 degree across all release positions. An analysis of variance and a post hoc Tukey test revealed that the mean error for the autodigitized trials was larger than that for the manually digitized trials. For the autodigitized trials, the static trials (release position=0 degrees) produced less mean error than the trials with movement produced. The ICCs showed a high degree of consistency among all raters, ranging from .707 to .999. CONCLUSION AND DISCUSSION: Our findings support the conclusion that under carefully controlled conditions, a 3-D motion measurement system can produce clinically acceptable measurements of accuracy across a range of angular speeds. Furthermore, acceptable accuracy is possible regardless of the digitization method.

Gait↗
PubMed1998

Paracrine and autocrine regulation of vascular endothelial growth factor during tissue differentiation in the quail.

The expression of vascular endothelial growth factor (VEGF) has been described to coincide both temporally and spatially with angiogenesis suggesting a role as a paracrine stimulator of endothelial cells. We have used digoxigenin labelled RNA probes to VEGF and the VEGF receptor-2 (Quek1) to investigate the relationship between VEGF expression and vascular events in quail embryos from day 1 to 13 of incubation. Furthermore, the effect of exogenously applied VEGF was studied in day 4 quail embryos using polyclonal anti-VEGF antibodies. Expression of VEGF mRNA was observed in day 1 and 2 embryos in regions of active angiogenesis and hemangiopoiesis. VEGF mRNA expression was found at high levels in the ventral aspect of the neural tube and Quek1 mRNA expression in the accompanying endothelial cells of day 3 embryos, suggesting a function in brain angiogenesis. However, in the neural tube, thyroid gland and cartilaginous skeleton VEGF mRNA was expressed at least 1 day before the ingrowth of vessels, suggesting that additional mechanisms are involved in control of angiogenesis. This is supported by the observation that application of VEGF165 into the midbrain induced dilatation of perineural vessels, while the intraneural vessels remained almost unaffected. Expression of VEGF mRNA was also observed at high levels in podocytes during all stages, indicative of its importance in glomerular development and function. The results of the present study indicate that as angiogenesis occurred in other tissues and organs (day 13 metanephros, dorsal third of the day 7 neural tube, skeletal muscle, and many mesodermal compartments), there was concurrent paracrine expression of VEGF mRNA and Quek1 mRNA. One noteable exception was the hepatocytes of the developing liver which appeared to remain VEGF-negative throughout the study. However, a small number of endothelial cells within liver sinuses, and additionally within the kidney and the elastic arteries, expressed VEGF mRNA. These results suggest that VEGF may also act as an autocrine mediator of angiogenesis, possibly as a result of localised tissue hypoxia.

Animals↗