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Biomedical subjects

R Griffiths

Publications and source records attributed to R Griffiths.

At least 37 records · Page 2Linked to original sources
PubMed2000

General versus spinal/epidural anaesthesia for surgery for hip fractures in adults.

BACKGROUND: The majority of hip fracture patients are treated surgically, requiring anaesthesia. OBJECTIVES: To compare different types of anaesthesia for surgical repair of hip fractures (proximal femoral fractures) in adults. This is primarily regional (spinal or epidural) anaesthesia versus inhalation general anaesthesia, but also includes ketamine anaesthesia versus inhalation general anaesthesia. SEARCH STRATEGY: We searched the Cochrane Musculoskeletal Injuries Group trials register, Medline, selected orthopaedic and anaesthetic journals and conference proceedings, and reference lists of relevant articles. Date of the most recent search: August 1998. SELECTION CRITERIA: Randomised and quasi-randomised trials comparing different methods of anaesthesia for hip fracture surgery in skeletally mature persons. Trials comparing the use of local nerve blocks are not considered in this review. Neither are trials using different types of drugs or techniques with one type of anaesthesia. The primary outcome was mortality. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality, using a nine item scale, and extracted data. The other two reviewers independently checked these results. Wherever appropriate and possible, results were pooled. MAIN RESULTS: Fifteen trials, involving 2162 patients, which compared regional anaesthesia with general anaesthesia, were included. All trials had methodological flaws. Regional anaesthesia was associated with a decreased mortality at one month (49/766 (6.4%) versus 76/812 (9.4%)) of borderline statistical significance (Peto odds ratio 0.66, 95% confidence interval 0.46 to 0.96)). The results for three month mortality were not statistically significant, although the confidence interval does not exclude the possibility of a clinically relevant reduction (86/726 (11.8%) versus 98/765 (12.8%), Peto odds ratio 0.91, 95% confidence interval 0.67 to 1.24). The reduced numbers at one year, coming exclusively from two studies, preclude any useful conclusions for long term mortality (80/354 (22.6%) versus 78/372 (21.0%), Peto odds ratio 1.10, 95% confidence interval 0.77 to 1.57). Regional anaesthesia was associated with a tendency to a longer operation (weighted mean difference 4.8 minutes, 95% confidence interval 1.1 to 8.6 minutes), and a reduced risk of deep venous thrombosis (39/129 (30%) versus 61/37(76%); Peto odds ratio 0. 41, 95% confidence interval 0.23 to 0.72), although this conclusion is insecure due to possible selection bias in the subgroups in whom this outcome was measured. No other statistically significant differences in outcome were identified. There was insufficient evidence to draw any conclusions from a further two included trials, involving a total of 100 patients, which compared other types of anaesthesia. REVIEWER'S CONCLUSIONS: Regional anaesthesia and general anaesthesia appear to produce comparable results for most of the outcomes studied. Regional anaesthesia may reduce short-term mortality but no conclusions can be drawn for longer term mortality.

Adult↗
PubMed2000

Nerve blocks (subcostal, lateral cutaneous, femoral, triple, psoas) for hip fractures.

BACKGROUND: Various nerve blocks using local anaesthetic agents have been used in order to reduce pain after hip fracture. OBJECTIVES: To determine the effects of nerve blocks (inserted either pre-operatively, operatively or post-operatively) as part of the treatment for a hip fracture. SEARCH STRATEGY: The Cochrane Musculoskeletal Injuries Group trials register, MEDLINE, and bibliographies of trial reports were searched. Date of the most recent search: April 1998. SELECTION CRITERIA: Randomised and quasi-randomised trials involving the use of nerve blocks as part of the care of a hip fracture patient. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality, by use of an eight item scale, and extracted data. Wherever appropriate, results of outcome measures were pooled. MAIN RESULTS: Six randomised or quasi-randomised trials involving 229 patients were included. One trial related to insertion of a nerve block pre-operatively and the remaining five, to peri-operative insertion. Nerve blocks resulted in a reduction of the quantity of parental or oral analgesia administered to control pain from the fracture/operation or during surgery. It was not possible to demonstrate if this reduction in analgesia use was associated with any clinical benefit. REVIEWER'S CONCLUSIONS: Because of the small number of patients included in this review and the differing type of nerve blocks and timing of insertion, it is not possible to determine if nerve blocks confer any benefit when compared with other analgesic methods as part of the treatment of a hip fracture. Further trials with larger numbers of patients and full reporting of clinical outcomes would be justified.

Hip Fractures↗
PubMed2000

Preliminary evaluation of an in vitro test for assessment of excitotoxicity by measurement of early gene (c-fos mRNA) levels.

Using primary cultures of mouse cerebellar granule cells as an in vitro model system, it has been demonstrated that different profiles of temporal expression of the c-fos proto-oncogene are observed under non-excitotoxic and excitotoxic conditions. A ratio has been derived previously for the steady-state level of c-fos mRNA after 30 min and 240 min which suggests that a 240 min/30 min ratio of greater than 1 correlates with excitotoxicity, whereas a ratio of less than 1 correlates with a non-excitotoxic outcome. Moreover, a positive correlation is seen with abrogation of excitotoxicity in response to selective excitatory amino acid receptor antagonists. This test, proposed as a specific biomarker for excitotoxicity is undergoing prevalidation. Excitotoxicity is defined as neuronal cell death mediated by hyperactivation of glutamate receptor subtypes and therefore might be expected to be prevented by selective glutamate receptor antagonists. In preliminary evaluation studies, we have conducted work under the direction of the European Center for Validation of Alternate Methods (ECVAM) using compounds specified by ECVAM that have been subdivided into four groups based on known or presumed actions. These groups comprise: Group 1-endogenous/synthetic excitotoxins; Group 2-environmental, putative excitotoxins; Group 3-neurotoxic but non-excitotoxic compounds, and Group 4-non-toxic compounds. The results of this study support the proposal that the c-fos mRNA time-ratio test is a specific biomarker of excitotoxicity. Just as importantly, this test has the potential for application in screening newly-designed EAA receptor antagonists in the search for clinically relevant drugs to treat a variety of neuropathologies.

Animals↗
PubMed2000

A further comment

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Journal Article↗
PubMed2000

The 50-millilitre syringe as an inexpensive training aid in the application of cricoid pressure.

A recent study in our department demonstrated that depressing the plunger of a 50-mL syringe was reliably and linearly related to the force applied between 20 N and 50 N. Using a 50-mL syringe we constructed a simple device to help train anaesthetic assistants to apply cricoid pressure correctly. We then tested anaesthetists, operating department practitioners (non-physicians) and nurses in our hospital to see if they could correctly apply forces of 20 and 40 N. All subjects were then trained using this apparatus and once confident were retested immediately afterwards, and again 1 week and 1 month later. The results show a wide variation in the force applied with only 30% of subjects applying appropriate force at 20 N, and 40% at 40 N. Training leads to a significant improvement in performance (P < 0.005 at 20 N and P < 0.001 at 40 N) which is maintained for 1 week for both 20 N (P < 0.05) and 40 N (P < 0.05) but not for 1 month. Therefore training should be practised on a weekly basis. This is an inexpensive and simple device that we believe to be useful in helping anaesthetic assistants to apply effective cricoid pressure.

Anesthesiology↗
PubMed2000

A role for leukotrienes in cyclosporine nephrotoxicity.

BACKGROUND: Nephrotoxicity associated with cyclosporine A (CsA) administration is characterized by marked renal vasoconstriction, interstitial fibrosis, and arteriolar hypertrophy. While the molecular mechanisms of CsA toxicity are not well characterized, previous studies have demonstrated that altered arachidonic acid (AA) metabolism plays a role its pathogenesis. Using a rat renal transplant model, the purpose of this study was to examine the effects of CsA on the 5-lipoxygenase (5-LO) pathway of AA metabolism. METHODS: The PVG (RT1c) strain of rats underwent kidney transplantation, and recipients of nonrejecting kidney transplants were treated with either 50 mg/kg/day CsA or vehicle (N = 24). To determine the physiologic significance of increased leukotriene (LT) production, the peptidoleukotriene receptor antagonist SKF 106203 was administered to CsA-treated animals for six days. RESULTS: CsA caused a substantial reduction in glomerular filtration rate (GFR) in the transplanted rats compared with the vehicle-treated controls (1.5 +/- 0.6 vs. 4.1 +/- 0.8 mL/min/kg, P < 0.05). The reduction in renal function was associated with enhanced urinary excretion of the peptidoleukotriene metabolites LTE4 (1431 +/- 207 vs. 953 +/- 125 pg/24 h, P < 0.05) and N-acetyl-LTE4 (4411 +/- 848 vs. 463 +/- 70 pg/24 h, P < 0.001). LT receptor blockade had a significant protective effect on renal transplant function in CsA-treated animals (GFR, 4.8 +/- 1.1 vs. 1.7 +/- 0.9 mL/min/kg, P < 0.05), such that CsA-treated animals that received SKF106203 maintained GFR at levels similar to controls that never received CsA (4.1 +/- 0.8 mL/min/kg). Peptidoleukotriene receptor blockade also prevented the histomorphological abnormalities caused by CsA, including tubular vacuolization. CONCLUSIONS: These studies identify a critical role for LTs in the pathophysiology of CsA nephrotoxicity and suggest that LT antagonists may be useful in preventing CsA-associated kidney toxicity.

Animals↗
PubMed2000

General versus regional anaesthesia for hip fracture surgery: a meta-analysis of randomized trials.

Hip fracture surgery is common and the population at risk is generally elderly. There is no consensus of opinion regarding the safest form of anaesthesia for these patients. We performed a meta-analysis of 15 randomized trials that compare morbidity and mortality associated with general or regional anaesthesia for hip fracture patients. There was a reduced 1-month mortality and incidence of deep vein thrombosis in the regional anaesthesia group. Operations performed under general anaesthesia had a reduction in operation time. No other outcome measures reached a statistically significant difference. There was a tendency towards a lower incidence of myocardial infarction, confusion and postoperative hypoxia in the regional anaesthetic group, and cerebrovascular accident and intra-operative hypotension in the general anaesthetic group. We conclude that there are marginal advantages for regional anaesthesia compared to general anaesthesia for hip fracture patients in terms of early mortality and risk of deep vein thrombosis.

Anesthesia, Conduction↗
PubMed2000

Development of a client-generated health outcome measure for community nursing.

OBJECTIVE: To develop a client-generated outcome measure for use in community nursing. METHOD: Participants for the study were identified from the case load of community health nurses, from a nursing home service and from residents of a retirement village. All participants had a diagnosis of venous leg ulcer (VLU) and/or type 2 diabetes. Preliminary development of the measure involved focus groups of community clients and health professionals, and pilot testing of an existing quality of life (QoL) measure, the Patient-Generated Index. The resulting Client-Generated Index was tested for reliability and validity. RESULTS: The Pearson's correlation coefficient between administration of the CGI at T1 and T2 was 0.526 (n = 51; p = 0.0001). The CGI correlated significantly with four of eight dimensions of the SF-36, and with pain as a clinical marker for VLU r = 0.54 (p = 0.001). Overall, participants with VLU reported a lower QoL (mean CGI score 2.8) compared to those with diabetes (mean CGI score 4.1). CONCLUSIONS: The CGI was developed to measure outcomes in community health settings. Some measures of its reliability and validity are demonstrated and further research is needed to validate the instrument using other client groups. IMPLICATIONS: If routine assessment and evaluation is to contribute to measures of outcome, the instruments need to be concise and acceptable to health care providers. The CGI has all these properties.

Community Health Nursing↗
PubMed2000

Anaesthetic drugs.

Explore the source record for details and available documents.

Adjuvants, Anesthesia↗
PubMed2000

Supportive pharmacology.

We continue to explore the basics of anaesthesia with another article from Rachelle Griffiths, this month looking at supportive pharmacology. If you think this looks too complicated for a Back to Basics piece, read it in small chunks--and be grateful that you are not my spelling checker, which has gone berserk! This Back to Basics series is drawing to a close soon. However, if you have suggestions for any more articles, or perhaps an article itself, then do contact me via Headquarters.

Anesthesia↗
PubMed2000

Back to basics in anaesthesia.

This is the last in the Back to Basics series of articles--for now at least. I would like to thank all the authors for their pieces. I've learnt and relearnt from each of them. The completed set of articles will be available as one document in October, and will be launched at Congress--yet another reason to attend! Bye for now.

Anesthesia, Conduction↗
PubMed2000

Evaluation of the use of accelerated infusions for the determination of pharmacokinetic linearity.

Accelerated infusions are potentially useful in the investigation of pharmacokinetic linearity. However, little information exists to validate this technique or to demonstrate its limitations. This investigation was performed to determine whether accelerated infusion regimens reliably estimate the range of pharmacokinetic linearity for molecules of varying pharmacokinetic properties, to evaluate the ability of accelerated infusions to identify pharmacokinetic nonlinearity, and to validate the accelerated infusion technique using compounds with known pharmacokinetic parameters. Simulations incorporating accelerated infusion as the input function resulted in the anticipated concentration-time profiles that contained an initial lag phase before reaching a linear slope. This lag phase increased with increasing distributional volume and in some instances was sufficiently great to obscure or prevent the linear portion of the profile. These simulations also revealed that clearance estimated from the apparently linear portion of the concentration-time profile can be erroneous under some conditions, as for large-volume compounds. Simulations of structured nonlinearity produced the predicted profiles for compounds with low to moderate volumes of distribution while demonstrating that modeling of data derived from compounds with large volumes of distribution may be inaccurate. Finally, experiments using accelerated infusions with various test compounds further demonstrated the usefulness of this technique while presenting limits imposed on the interpretation of the data. The results of this investigation indicate that the accelerated infusion may be used to determine pharmacokinetic linearity for compounds within certain pharmacokinetic boundaries, but that appropriate caution should be exercised in the extent of interpretation that should be extracted from such studies.

Algorithms↗
PubMed1999

Experimental demonstration that offspring sex ratio varies with maternal condition.

Sex ratio theory predicts that, if prevailing ecological or social circumstances differentially influence the fitness benefits of offspring of each sex, parents should adjust their production accordingly to maximize fitness. For species in which sex is chromosomally determined, such as birds and mammals, a differential effect of maternal condition on the fitness of male and female young is one important route whereby selection is expected to favor a bias in the offspring sex ratio at birth or egg laying. However, despite its central place in sex allocation theory, this hypothesis has rarely been tested in wild populations. We manipulated maternal condition upward and downward in a sexually dimorphic wild bird and examined the effect on offspring survival and on offspring sex ratio. The survival to fledging of male, but not female, young was substantially reduced if they came from less well provisioned eggs produced by females in relatively poor condition. As female condition, and thereby her capacity to produce high quality eggs, declined, she progressively skewed the sex ratio of her eggs toward females; i.e., she produced more of the sex with the higher survival prospects. The decline in the survival of male offspring, and the sex ratio bias, was removed when maternal condition was enhanced. These results provide experimental evidence of an adaptive, facultative adjustment of sex ratio in response to changes in maternal condition in wild birds.

Adaptation, Biological↗
PubMed1999

Preferences for ultraviolet partners in the blue tit.

The preference of female blue tits, Parus caeruleus, is correlated with the brightness of the ultraviolet (UV) crest; there is also assortative mating with respect to the crest's UV/violet chroma. However, manipulation of plumage reflectance is necessary to infer a direct causal link between UV plumage and mate choice. We gave both male and female blue tits a choice between a UV-reflecting ('UV+') partner and a partner whose UV plumage reflectance had been removed ('UV-'). Male blue tits significantly preferred UV+ females. Similarly, female blue tits tended to prefer UV-reflecting males, but their UV+ preferences were nonsignificant. Neither sex showed a preference when conspecifics were replaced by a heterospecific. This study suggests mutual mate choice but male choice may be more strongly influenced by the visual appearance of potential mates. This is one of a few studies to show male mate preferences and the first demonstration of a direct relationship between UV reflectance and male mate choice. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗