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R A Dickson

Publications and source records attributed to R A Dickson.

At least 19 recordsLinked to original sources
PubMed2006

Antimicrobial, resistance-modifying effects, antioxidant and free radical scavenging activities of Mezoneuron benthamianum Baill., Securinega virosa Roxb. &Wlld. and Microglossa pyrifolia Lam.

Mezoneuron benthamianum, Securinega virosa and Microglossa pyrifolia are used in folk medicine in Ghana for the treatment of dermal infections and wounds. Petroleum spirit, chloroform and ethanol extracts of the plants were tested for antimicrobial activity against a battery of organisms using the agar well diffusion technique and a serial dilution microassay. The resistance modifying activities of these extracts on standard antibiotics against Staphylococcus aureus possessing efflux mechanisms of resistance have also been assessed. A 4-fold potentiation of the activity of norfloxacin was observed for ethanol and chloroform extracts of M. benthamianum and S. virosa, respectively, whilst the petroleum spirit extract resulted in a 2-fold potentiation with minimum inhibitory concentration (MIC) values in the range 8-16 microg/mL. Ethanol extracts of all three species, the petroleum spirit extract of M. benthamianum and the chloroform extracts of M. benthamianum and S. virosa, showed interesting antimicrobial activities. Antioxidant and free radical scavenging activities using DPPH spectrophotometric and TBA lipid peroxidation assays were also conducted. Of the five extracts that showed antioxidant activities, the petroleum spirit and chloroform extracts of M. benthamianum rated most highly by displaying strong free radical scavenging activity with IC50 values of 15.33 and 19.72 microg/mL, respectively. Lipid peroxidation inhibition provided by the same two extracts also produced the lowest IC50 values for all the extracts tested, of 23.15 and 30.36 microg/mL. These findings therefore give some support to the ethnopharmacological use of the plants in the treatment of various skin diseases and wounds, as well as demonstrating the potential of some of the plants as sources of compounds possessing the ability to modulate bacterial multidrug resistance.

Animals↗
PubMed2004

Scoliosis in cystic fibrosis: is it idiopathic?

STUDY DESIGN: This is a retrospective study of all the patients registered with the Yorkshire Regional Cystic Fibrosis unit from 1982 to 1997. Of the 316 patients, there were 184 adults (age 17 years and above) and 132 children (age 0-6 years). OBJECTIVES: This study was aimed at determining the prevalence of scoliosis in people with cystic fibrosis and describes the characteristics and progression of scoliosis in these patients and highlights predictive factors, which account for high prevalence of scoliosis in this condition. SUMMARY OF THE BACKGROUND DATA: Two previous North American studies (1978 and 1982) have indicated a high prevalence of scoliosis in patients with cystic fibrosis. METHODS: The patients were divided into 3 groups based on their chronologic age as on January 1998. Chest, abdomen, and whole spine radiographs were studied for the presence of any spinal deformity, and measurements were made using the Oxford Cobbmeter (Oxford Metrics). The extent, apex, and the side of the curves were described. The disease-specific scores, ie, Chrispin-Norman score (score for radiologic severity of lung disease) and Shwachman score (score for general condition), were noted from the patient follow-up database maintained by the Regional Cystic Fibrosis Unit. Multiple linear regression analysis was used to study the correlation between Cobb angle and the previously mentioned scores. RESULTS: In the 4- to 16-year age group, the prevalence of scoliosis was 15.6%, which is 20 times the prevalence in 15,793 school children with a similar age and sex distribution from the same geographic area. The majority of curves were single-thoracic, apical around T6-T8 with no side predilection. In the adult population (above 16 years), the prevalence was 9.8%, which is higher than that of the general population. These curves were thoracic, apical around T7-T8, and approximately two thirds of them were right-sided. Infantile curves are described for the first time in our study; these tend to be nonprogressive, right-sided, upper thoracic curves. CONCLUSION: Our study shows a high prevalence of scoliosis in people with cystic fibrosis. These are benign short midthoracic curves, apical between T6-T8 with no side predilection.

Adolescent↗
PubMed2004

A dynamic investigation of the burst fracture process using a combined experimental and finite element approach.

Spinal burst fractures account for about 15% of spinal injuries and, because of their predominance in the younger population, there are large associated social and healthcare costs. Although several experimental studies have investigated the burst fracture process, little work has been undertaken using computational methods. The aim of this study was to develop a finite element model of the fracture process and, in combination with experimental data, gain a better understanding of the fracture event and mechanism of injury. Experimental tests were undertaken to simulate the burst fracture process in a bovine spine model. After impact, each specimen was dissected and the severity of fracture assessed. Two of the specimens tested at the highest impact rate were also dynamically filmed during the impact. A finite element model, based on CT data of an experimental specimen, was constructed and appropriate high strain rate material properties assigned to each component. Dynamic validation was undertaken by comparison with high-speed video data of an experimental impact. The model was used to determine the mechanism of fracture and the postfracture impact of the bony fragment onto the spinal cord. The dissection of the experimental specimens showed burst fractures of increasing severity with increasing impact energy. The finite element model demonstrated that a high tensile strain region was generated in the posterior of the vertebral body due to the interaction of the articular processes. The region of highest strain corresponded well with the experimental specimens. A second simulation was used to analyse the fragment projection into the spinal canal following fracture. The results showed that the posterior longitudinal ligament became stretched and at higher energies the spinal cord and the dura mater were compressed by the fragment. These structures deformed to a maximum level before forcing the fragment back towards the vertebral body. The final position of the fragment did not therefore represent the maximum dynamic canal occlusion.

Animals↗
PubMed2004

Therapeutic impact of percutaneous spinal biopsy in spinal infection.

OBJECTIVE: To investigate the therapeutic impact of percutaneous spinal biopsy in patients with suspected spinal infection. DESIGN AND PATIENTS: A review of the case notes and imaging features of 36 patients who underwent percutaneous spinal biopsy was performed. From this group 20 patients with a prebiopsy diagnosis of spinal osteomyelitis were identified. Management before biopsy was noted including the use of antimicrobial therapy. The results of the histology and microbiology were noted along with the subsequent diagnosis and management. RESULTS: Eight of the 20 patients (40%) had received antibiotics before the biopsy. An organism was isolated in 8/20 cases (40%). Of the eight patients on antibiotics, two grew an organism (25%), including one case of candida in a patient receiving flucloxacillin. Out of 12 patients not on antibiotics there were six cases where an organism was isolated (50%). The result of the biopsy led to a change in management in seven of the 20 patients (35%). CONCLUSIONS: Many clinicians are treating spinal osteomyelitis empirically with antibiotics before biopsy, but this reduces the chance of isolating an organism and determining antibiotic sensitivity. Despite this biopsy led to a change in management in 35% of cases.

Adolescent↗
PubMed2002

Measurement of canal occlusion during the thoracolumbar burst fracture process.

Post-injury CT scans are often used following burst fracture trauma as an indication for decompressive surgery. Literature suggests, however, that there is little correlation between the observed fragment position and the level of neurological injury or recovery. Several studies have aimed to establish the processes that occur during the fracture using indirect methods such as pressure measurements and pre/post impact CT scans. The purpose of this study was to develop a direct method of measuring spinal canal occlusion during a simulated burst fracture by using a high-speed video technique. The fractures were produced by dropping a mass from a measured height onto three-vertebra bovine specimens in a custom-built rig. The specimens were constrained to deform only in the impact direction such that pure compression fractures were generated. The spinal cord was removed prior to testing and the video system set up to film the inside of the spinal canal during the impact. A second camera was used to film the outside of the specimen to observe possible buckling during impact. The video images were analysed to determine how the cross-sectional area of the spinal canal changed during the event. The images clearly showed a fragment of bone being projected from the vertebral body into the spinal canal and recoiling to the final resting position. To validate the results, CT scans were taken pre- and post-impact and the percentage canal occlusion was calculated. There was good agreement between the final canal occlusion measured from the video images and the CT scans.

Animals↗
PubMed2002

Indications of disordered eating behaviour in adolescent patients with idiopathic scoliosis.

We have investigated whether patients with adolescent-onset idiopathic scoliosis (AIS) are more likely to have a low body-weight. Measurements of weight, height and body mass index (BMI) were made in 44 young women with AIS and compared with age- and gender-adjusted normative data. The body mass criteria of the International Classification of Diseases for eating disorders was used to determine how many patients were within the range considered to be 'eating disordered'. Compared with the normative data, the AIS group did not differ significantly in terms of height, (p = 0.646), but they were significantly lighter (p < 0.001) and had significantly lower BMI scores (p < 0.001); 25% of the series had BMI scores which were within the range considered to be anorexic. The relationship between a diagnosis of AIS and low body-weight may indicate disordered eating and is thus a cause for concern, particularly in the light of the well-established relationship between eating psychopathology and osteoporosis. Aspects of organic health may need to be considered in addition to the cosmetic deformity.

Adolescent↗
PubMed2001

Non-invasive ventilation in the treatment of ventilatory failure following corrective spinal surgery.

Non-invasive positive pressure ventilation has previously been used successfully to treat both acute and chronic ventilatory failure secondary to a number of conditions, including scoliosis. We report two patients in whom it was used, on three separate occasions, to treat acute ventilatory failure following corrective spinal surgery. Non-invasive positive pressure ventilation may be useful postoperatively in high-risk patients undergoing major spinal surgery in an attempt to prevent intubation and its attendant complications.

Adolescent↗
PubMed2000

Immediate IL-10 expression following major orthopaedic trauma: relationship to anti-inflammatory response and subsequent development of sepsis.

OBJECTIVE: To assess the relationship between IL-10 release and anti-inflammatory response following blunt trauma. DESIGN: Prospective longitudinal clinical study. SETTING: Departments of trauma and anaesthetics in a university teaching hospital. PATIENTS: Forty-eight adult patients with a mean injury severity score of 14.5 (range 9-57) were prospectively studied following blunt trauma. MEASUREMENTS AND RESULTS: Venous blood samples were collected on arrival and at 16 and 24 h, and at 3, 5, and 7 days. Peripheral blood mononuclear cell (HLA-DR) expression on CD14 + monocytes was quantified by flow cytometry and serum IL-10 was assayed by ELISA. Anti-inflammatory response was defined as monocyte HLA-DR expression of less than 30% of that seen in healthy controls. Serum IL-10 levels in trauma patients on arrival was significantly elevated, 70.0 [48.0-92.1, 95% confidence interval, (CI)] compared to the control group, 3 (0-5) (P < 0.0001), and monocyte HLA-DR expression was significantly lower, 14.2 (12.1-16.3, 95% CI), in patients versus 25.2 (22.4-28.1) in controls (P < 0.001). Patients with low HLA-DR expression (n = 14) had significantly higher serum IL-10 levels than those whose HLA-DR expression remained above 30% of the control value (n = 34), (P < 0.038). In patients who developed sepsis (n = 11), serum IL-10 levels were greater on admission, [143.7 (80.2-207.2) pg/ml(-1)], and remained elevated during the study period compared with non-complicated patients, [50.16 (33.5-66.8) pg/ml(-1)]. Immediate IL-10 (2 h following trauma) was negatively correlated with simultaneous HLA-DR expression, (r = -0.49, P = 0.0005). CONCLUSION: These findings support the view that IL-10 release regulates monocyte HLA-DR expression and may be related to an anti-inflammatory response and development of sepsis following trauma.

Adult↗
PubMed2000

Interleukin-10 release and monocyte human leukocyte antigen-DR expression during femoral nailing.

This study determined the effect of femoral nailing on the expression of monocyte Class II antigens and interleukin-10 release and sought to differentiate any differences in the release of these elements of immune reactivity in patients undergoing reamed and unreamed nailing. Thirty-two patients presenting with an acute femoral fracture were studied. In 15 patients, the femoral fracture was stabilized with a reamed technique and in 17 patients with an unreamed technique. Venous blood samples were taken at presentation, at anesthetic induction, immediately after nail insertion, and subsequently at 1, 4, and 24 hours and at 3, 5, and 7 days after surgery. Serum interleukin-10 was measured by an enzyme-linked immunosorbent assay, and monocyte human leukocyte antigen-DR expression was quantified by flow cytometry. Serum interleukin-10 release and human leukocyte antigen-DR expression on monocytes showed a clear response to the nailing procedure. The group of patients undergoing a reamed femoral nailing procedure showed significantly higher interleukin-10 release and a significant depression in the expression of human leukocyte antigen-DR on monocytes compared with those whose nail had been inserted unreamed. One patient in the reamed femoral nailing group died of adult respiratory distress syndrome 3 days after injury. Reamed intramedullary nailing appears to be associated with greater impairment of immune reactivity than is the unreamed nailing technique.

Adolescent↗
PubMed2000

Does 'canal clearance' affect neurological outcome after thoracolumbar burst fractures?

Surgical decompression of the spinal canal is presently accepted worldwide as the method of treatment for thoracolumbar burst fractures with neurological deficit in the belief that neurological recovery may be produced or enhanced. Our clinical and laboratory experience, however, indicates that the paralysis occurs at the moment of injury and is not related to the position of the fragments of the fracture on subsequent imaging. Since the preoperative geometry of the fracture may be of no relevance, our hypothesis, backed by more than two decades of operative experience, is that alteration of the canal by 'surgical clearance' does not affect the neurological outcome. We have reviewed the existing world literature in an attempt to find evidence-based justification for the variety of surgical procedures used in the management of these fractures. We retrieved 275 publications on the management of burst fractures of which 60 met minimal inclusion criteria and were analysed more closely. Only three papers were prospective studies; the remainder were retrospective descriptive analyses. None of the 60 articles included control groups. The design of nine studies was sufficiently similar to allow pooling of their results, which failed to establish a significant advantage of surgical over non-surgical treatment as regards neurological improvement. Significant complications were reported in 75% of papers, including neurological deterioration. Surgical treatment for burst fracture in the belief that neurological improvement can be achieved is not justified, although surgery may still occasionally be indicated for structural reasons. This information should not be withheld from the patients.

Decompression, Surgical↗
PubMed2000

Hormonal side effects in women: typical versus atypical antipsychotic treatment.

Neuroleptic-induced hyperprolactinemia can cause menstrual disorders, impaired fertility, galactorrhea, and sexual dysfunction, as well as hypoestrogenism secondary to disruption of the hypothalamic-pituitary-ovarian axis. The development of the prolactin-sparing atypical antipsychotic drugs offers prevention and resolution of these adverse reactions. Thus far, this property of the new medications has received insufficient clinical attention. The authors use case vignettes to discuss assessment and management of clinical situations that arise as a result of antipsychotic-induced endocrine changes.

Adult↗
PubMed1999

Neuroleptic-induced hyperprolactinemia.

Neuroleptic-induced hyperprolactinemia (NIHP) has been a 'cost' of traditional antipsychotic therapy. Because all of the traditional neuroleptics are capable of elevating serum prolactin, clinicians have had to accept the implications of NIHP along with the antipsychotic's efficacy. Accordingly, the clinical consequences of NIHP have received limited attention. With the introduction of some of the new, more highly selective mesolimbic and mesocortical dopamine-blocking, prolactin-sparing antipsychotic drugs, NIHP may now be prevented or minimized. Given this possibility, it becomes more important than ever that clinicians understand both the short- and long-term consequences of hyperprolactinemia and current management approaches.

Antipsychotic Agents↗
PubMed1999

Hospital days in risperidone-treated patients.

OBJECTIVE: To compare inpatient hospital days of a group of "real world" schizophrenia-spectrum patients for 3 years prior to and 3 years after risperidone initiation. METHOD: This is a retrospective cohort study using a mirror-image design of hospital days in 120 patients over a 6-year period. Hospital admission and discharge information was obtained from chart review and database extraction at 3 outpatient treatment sites. The sample comprised all patients attending these clinics who were prescribed risperidone during the first year of the drug's release. RESULTS: Patients separated into 3 treatment groups: those who were prescribed risperidone for 3 uninterrupted years (N = 35), those who interrupted but resumed risperidone use and were prescribed the drug at 3 years (N = 8), and those who discontinued risperidone during the 3-year follow-up period (N = 77). The group continuing risperidone to 3 years demonstrated a significant decrease in hospital days after risperidone treatment, in contrast to the other 2 groups. The reduction in inpatient days for the total sample was not statistically significant. CONCLUSION: In this outpatient clinic sample, the 29% of patients who continued on risperidone showed a significant reduction in inpatient hospital days, from an average of 17.2 days per year in the 3 years before risperidone treatment to an average of 2.1 days per year for the 3 years of risperidone treatment.

Adult↗
PubMed1999

Stimulation of the inflammatory system by reamed and unreamed nailing of femoral fractures. An analysis of the second hit.

It has been suggested that reamed intramedullary nailing of the femur should be avoided in some patients with multiple injuries. We have studied prospectively the effect of femoral reaming on the inflammatory process as implicated in the pathogenesis of acute respiratory distress syndrome (ARDS) and multiple-organ failure (MOF). We studied changes in the levels of serum interleukin-6 (IL-6) (proinflammatory cytokine), neutrophil CD11b (C3) receptor expression (activated neutrophil adhesion molecule), serum soluble intracellular adhesion molecule (s-ICAM-1), serum soluble E-selectin (the soluble products of endothelial adhesion molecules) and plasma elastase (neutrophil protease) in a series of patients with femoral fractures treated by nailing. We have also compared reamed nailing with unreamed nailing. We found that the levels of serum IL-6 and elastase rose significantly during the nailing procedure indicating a measurable 'second hit'. There was no clear response in leukocyte activation and no difference in the release of endothelial adhesion molecule markers. There was no significant difference between groups treated by reamed and unreamed nailing. Although clinically unremarkable, the one patient who died from ARDS was shown to be hyperstimulated after injury and again after nailing, suggesting the importance of an excessive inflammatory reaction in the pathogenesis of these serious problems. Our findings have shown that there is a second hit associated with femoral nailing and suggest that the degree of the inflammatory reaction may be important in the pathogenesis of ARDS and MOF.

Adolescent↗