Candidate Electromagnetic Counterpart to the Binary Black Hole Merger Gravitational-Wave Event S190521g

We report the first plausible optical electromagnetic counterpart to a (candidate) binary black hole merger. Detected by the Zwicky Transient Facility, the electromagnetic flare is consistent with expectations for a kicked binary black hole merger in the accretion disk of an active galactic nucleus [B. McKernan, K. E. S. Ford, I. Bartos et al., Astrophys. J. Lett. 884, L50 (2019)AJLEEY2041-821310.3847/2041-8213/ab4886] and is unlikely [<O(0.01%))] due to intrinsic variability of this source. The lack of color evolution implies that it is not a supernova and instead is strongly suggestive of a constant temperature shock. Other false-positive events, such as microlensing or a tidal disruption event, are ruled out or constrained to be <O(0.1%). If the flare is associated with S190521g, we find plausible values of total mass M_{BBH}∼100  M_{⊙}, kick velocity v_{k}∼200  km s^{-1} at θ∼60° in a disk with aspect ratio H/a∼0.01 (i.e., disk height H at radius a) and gas density ρ∼10^{-10}  g cm^{-3}. The merger could have occurred at a disk migration trap (a∼700r_{g}; r_{g}≡GM_{SMBH}/c^{2}, where M_{SMBH} is the mass of the active galactic nucleus supermassive black hole). The combination of parameters implies a significant spin for at least one of the black holes in S190521g. The timing of our spectroscopy prevents useful constraints on broad-line asymmetry due to an off-center flare. We predict a repeat flare in this source due to a reencountering with the disk in ∼1.6  yr(M_{SMBH}/10^{8}  M_{⊙})(a/10^{3}r_{g})^{3/2}.

Optical polarization properties of (11-22) semi-polar InGaN LEDs with a wide spectral range

Electroluminescence polarization measurements have been performed on a series of semi-polar InGaN light emitting diodes (LEDs) grown on semi-polar (11–22) templates with a high crystal quality. The emission wavelengths of these LEDs cover a wide spectral region from 443 to 555 nm. A systematic study has been carried out in order to investigate the influence of both indium content and injection current on polarization properties, where a clear polarization switching at approximately 470 nm has been observed. The shortest wavelength LED (443 nm) exhibits a positive 0.15 polarization degree, while the longest wavelength LED (555 nm) shows a negative −0.33 polarization degree. All the longer wavelength LEDs with an emission wavelength above 470 nm exhibit negative polarization degrees, and they further demonstrate that the dependence of polarization degree on injection current enhances with increasing emission wavelength. Moreover, the absolute value of the polarization degree decreases with increasing injection current. In contrast, the polarization degree of the 443 nm blue LED remains constant with changing injection current. This discrepancy can be attributed to a significant difference in the density of states (DOS) of the valence subbands.

Putative Nox2 inhibitors worsen homocysteine-induced impaired acetylcholine-mediated relaxation

BACKGROUND AND AIM

Increased homocysteine (Hcy) is associated with coronary artery disease (CAD). Hcy increases reactive oxygen species (ROS) via NADPH oxidases (Nox), reducing acetylcholine-mediated vasorelaxation. We aimed to determine if putative Nox2 inhibitors prevent Hcy-impaired acetylcholine-mediated vasorelaxation.

METHODS AND RESULTS

New Zealand White rabbit and wild-type (C57BL/6) and Nox2^-/- (NOX) mice aortic rings were mounted in organ baths. Rabbit rings were incubated with either apocynin (10 μM), gp91ds-tat (GP, 1 μM) or PhoxI2 (1 μM) and mice rings GP (1 μM) only. Some rabbit rings were incubated with 3 mM Hcy, before pre-contraction, followed by dose-response relaxation to acetylcholine (ACh; 0.01μM-10μM). In rabbit rings treated with Hcy and GP, O₂‾ donor pyrogallol (1 μM) or Akt activator SC79 (1 μM) was added 5 min before ACh. Mice rings were used to compare Nox2 deletion to normal acetylcholine-mediated relaxation. In rabbits, Hcy reduced acetylcholine-mediated relaxation vs. control (p < 0.0001). Treatment + Hcy reduced relaxation compared with treatment alone (p < 0.0001). Pyrogallol and SC79 reversed the response of GP + Hcy (p = 0.0001). In mice, Nox2 deletion reduced acetylcholine-mediated vasorelaxation. Rabbit tissue analysis revealed that Hcy reduced eNOS phosphorylation at Thr⁴⁹⁵ and increased eNOS phosphorylation at Ser¹¹⁷⁷; no further alteration at Thr⁴⁹⁵ was observed with GP. In contrast, GP prevented increased phosphorylation at Ser¹¹⁷⁷.

CONCLUSIONS

Apocynin, GP and PhoxI2 worsens acetylcholine-mediated vascular relaxation in rabbit aorta, which is supported by results from mouse Nox2 deletion data. These inhibitors worsen Hcy-induced vascular dysfunction, suggesting that current putative Nox2 inhibitors might not be useful in treating HHcy.

Monolithically multi-color lasing from an InGaN microdisk on a Si substrate

An optically pumped multi-color laser has been achieved using an InGaN/GaN based micro-disk with an undercut structure on a silicon substrate. The micro-disk laser has been fabricated by means of a combination of a cost-effective microsphere lithography technique and subsequent dry/wet etching processes. The microdisk laser is approximately 1 μm in diameter. The structure was designed in such a way that the vertical components of the whispering gallery (WG) modes formed can be effectively suppressed. Consequently, three clean lasing peaks at 442 nm, 493 nm and 522 nm have been achieved at room temperature by simply using a continuous-wave diode laser as an optical pumping source. Time-resolved micro photoluminescence (PL) measurements have been performed in order to further confirm the lasing by investigating the excitonic recombination dynamics of these lasing peaks. A three dimensional finite-difference-time-domain (FDTD) simulation has been used for the structure design.

Role of Nox inhibitors plumbagin, ML090 and gp91ds-tat peptide on homocysteine thiolactone induced blood vessel dysfunction

Antioxidants have not reduced the burden of cardiovascular disease, and current evidence suggests a beneficial role of oxidative stress, via NADPH oxidase (Nox) upregulation, in endothelial function. Homocysteine thiolactone (HcyT) induces blood vessel dysfunction and this correlates with increased vascular oxidative stress. This study aimed to determine if pharmacological inhibition of Nox could impair HcyT induced blood vessel dysfunction. Abdominal aorta were excised from New Zealand White rabbits (n = 6), cut into rings and sequentially mounted in organ baths. Rings were preincubated with 0.55 μmol/L homocysteine thiolactone for 1 h, or combinations of putative Nox inhibitors (plumbagin for Nox4, gp91ds-tat for Nox2, and ML090 for Nox1), 30 min prior to the addition of HcyT, followed by a dose response curve to acetylcholine on phenylephrine preconstricted rings. Plumbagin, ML090 + gp91ds-tat and HcyT reduced responses to acetylcholine, and Plumbagin + Hcyt caused constriction to acetylcholine, which was normalised to plumbagin by ML090. Plumbagin + ML090 or plumbagin + gp91ds-tat completely impaired the effect of acetylcholine. ML090 inhibited the effect of HcyT on reduced response to acetylcholine, whereas gp91ds-tat had no effect. This study concludes that inhibition of Nox1 prevents, whereas inhibition of Nox4 worsens, acetylcholine induced blood vessel relaxation caused by HcyT, while Nox2 inhibition has no effect. However combinations of Nox inhibitors worsen acetylcholine induced blood vessel relaxation. These results suggest that there is cross-talk between Nox isoforms during physiological and pathophysiological processes.

Caffeine and cardiovascular diseases: critical review of current research

Caffeine is a most widely consumed physiological stimulant worldwide, which is consumed via natural sources, such as coffee and tea, and now marketed sources such as energy drinks and other dietary supplements. This wide use has led to concerns regarding the safety of caffeine and its proposed beneficial role in alertness, performance and energy expenditure and side effects in the cardiovascular system. The question remains "Which dose is safe?", as the population does not appear to adhere to the strict guidelines listed on caffeine consumption. Studies in humans and animal models yield controversial results, which can be explained by population, type and dose of caffeine and low statistical power. This review will focus on comprehensive and critical review of the current literature and provide an avenue for further study.

Attainment of metabolic goals in the integrated UK islet transplant program with locally isolated and transported preparations

The objective was to determine whether metabolic goals have been achieved with locally isolated and transported preparations over the first 3 years of the UK's nationally funded integrated islet transplant program. Twenty islet recipients with C-peptide negative type 1 diabetes and recurrent severe hypoglycemia consented to the study, including standardized meal tolerance tests. Participants received a total of 35 infusions (seven recipients: single graft; 11 recipients: two grafts: two recipients: three grafts). Graft function was maintained in 80% at [median (interquartile range)] 24 (13.5-36) months postfirst transplant. Severe hypoglycemia was reduced from 20 (7-50) episodes/patient-year pretransplant to 0.3 (0-1.6) episodes/patient-year posttransplant (p < 0.001). Resolution of impaired hypoglycemia awareness was confirmed [pretransplant: Gold score 6 (5-7); 24 (13.5-36) months: 3 (1.5-4.5); p < 0.03]. Target HbA1c of <7.0% was attained/maintained in 70% of recipients [pretransplant: 8.0 (7.0-9.6)%; 24 (13.5-36) months: 6.2 (5.7-8.4)%; p < 0.001], with 60% reduction in insulin dose [pretransplant: 0.51 (0.41-0.62) units/kg; 24 (13.5-36) months: 0.20 (0-0.37) units/kg; p < 0.001]. Metabolic outcomes were comparable 12 months posttransplant in those receiving transported versus only locally isolated islets [12 month stimulated C-peptide: transported 788 (114-1764) pmol/L (n = 9); locally isolated 407 (126-830) pmol/L (n = 11); p = 0.32]. Metabolic goals have been attained within the equitably available, fully integrated UK islet transplant program with both transported and locally isolated preparations.

Disaster triage after the Haitian earthquake

In the aftermath of the devastating Haitian earthquake, we became the primary relief service for a large group of severely injured earthquake victims. Finding ourselves virtually isolated with extremely limited facilities and a group of critically injured patients whose needs vastly outstripped the available resources we employed a disaster triage system to organize their clinical care. This report describes the specific injury profile of this group of patients, their clinical course, and the management philosophy that we employed. It provides useful lessons for similar situations in the future.

The effect of ergometer design on rowing stroke mechanics

The effect of rowing ergometer design upon power delivery and coordination patterns of the rowing stroke was analyzed for 14 elite rowers. Rowers were tested in three ergometer conditions: the fixed stretcher Concept2c ergometer, the Concept2c ergometer mounted on sliding rails, and the sliding stretcher RowPerfect ergometer. Ergometers were instrumented to measure the external force generated at the handle and the foot stretcher and a nine-segment inverse dynamics model used to calculate joint and overall power delivery. Peak power generation and absorption at the knee joint was significantly greater, and total power delivered to the ergometer delayed on the fixed stretcher ergometer when compared to the sliding stretcher ergometers. No differences were found in the mechanical energy delivered to the handle of the three ergometers; however, greater joint mechanical energy production of the lower limb reduced mechanical efficiency when rowing the Concept2c fixed ergometer. The fixed foot stretcher on the Concept2c fixed ergometer acts to increase the inertial forces that the rower must overcome at the catch, increasing the moment and power output at the knee, and affecting the coordination pattern during the recovery phase.

Soil warming alters nitrogen cycling in a New England forest: implications for ecosystem function and structure

Global climate change is expected to affect terrestrial ecosystems in a variety of ways. Some of the more well-studied effects include the biogeochemical feedbacks to the climate system that can either increase or decrease the atmospheric load of greenhouse gases such as carbon dioxide and nitrous oxide. Less well-studied are the effects of climate change on the linkages between soil and plant processes. Here, we report the effects of soil warming on these linkages observed in a large field manipulation of a deciduous forest in southern New England, USA, where soil was continuously warmed 5°C above ambient for 7 years. Over this period, we have observed significant changes to the nitrogen cycle that have the potential to affect tree species composition in the long term. Since the start of the experiment, we have documented a 45% average annual increase in net nitrogen mineralization and a three-fold increase in nitrification such that in years 5 through 7, 25% of the nitrogen mineralized is then nitrified. The warming-induced increase of available nitrogen resulted in increases in the foliar nitrogen content and the relative growth rate of trees in the warmed area. Acer rubrum (red maple) trees have responded the most after 7 years of warming, with the greatest increases in both foliar nitrogen content and relative growth rates. Our study suggests that considering species-specific responses to increases in nitrogen availability and changes in nitrogen form is important in predicting future forest composition and feedbacks to the climate system.

Patient-reported outcomes following islet cell or pancreas transplantation (alone or after kidney) in Type 1 diabetes: a systematic review

AIMS

For selected individuals with complex Type 1 diabetes, pancreatic islet transplantation (IT) offers the potential of excellent glycaemic control without significant hypoglycaemia, balanced by the need for ongoing systemic immunosuppression. Increasingly, patient-reported outcomes (PROs) are considered alongside biomedical outcomes as a measure of transplant success. PROs in IT have not previously been compared directly with the closest alternate treatment option, pancreas transplant alone (PTA) or pancreas after kidney (PAK).

METHODS

We used a Population, Intervention, Comparisons, Outcomes (PICO) strategy to search Scopus and screened 314 references for inclusion.

RESULTS

Twelve studies [including PRO assessment of PAK, PTA, islet-after kidney (IAK) and islet transplant alone (ITA); n = 7-205] used a total of nine specified and two unspecified PRO measures. Results were mixed but identified some benefits which remained apparent up to 36 months post-transplant, including improvements in fear of hypoglycaemia, as well as some aspects of diabetes-specific quality of life (QoL) and general health status. Negative outcomes included short-term pain associated with the procedure, immunosuppressant side effects and depressed mood associated with loss of graft function.

CONCLUSIONS

The mixed results may be attributable to limited sample sizes. Also, some PRO measures may lack sensitivity to detect actual changes, as they exclude issues and domains of life likely to be important for QoL post-transplantation and when patients may no longer perceive themselves to have diabetes. Thus, the full impact of islet/pancreas transplantation (alone or after kidney) on QoL is unknown. Furthermore, no studies have assessed patient satisfaction, which may highlight further advantages and disadvantages of transplantation.

The relationship between knee adduction moment and cartilage and meniscus morphology in women with osteoarthritis

OBJECTIVE

The aim of this cross-sectional study is to investigate the relationship between knee adduction moment and knee adduction angular impulse and meniscus, cartilage and bone morphology in women with knee osteoarthritis (OA).

METHOD

Forty-five women aged >40 years with OA in at least one knee, according to American College of Rheumatology clinical criteria were studied. The knee joint loading was assessed by three-dimensional motion analysis system during gait. Three Tesla magnetic resonance imaging (MRI) with a coronal T2-weighted spin echo sequence was used for evaluating meniscus pathology, and a coronal T1-weighted gradient echo sequence for quantifying cartilage morphology and bone surface size. Cartilage thickness, denuded area and subchondral area in the femorotibial joint was measured using custom software.

RESULTS

A higher peak knee adduction moment was observed in participants with medial compared to those with lateral tears (2.92+/-1.06 vs -0.46+/-1.7, P<0.001). Participants with a higher knee adduction moment displayed a larger medial meniscus extrusion (r=0.532, P<0.001) and a lower medial meniscus height (r=-0.395, P=0.010). The inverse relationship was observed for the lateral meniscus. A higher knee adduction moment was also associated with a higher ratio of the medial to lateral tibial subchondral bone area (r=0.270, P=0.035). By contrast, cartilage thickness and denuded areas in the femur and tibia were not related to the knee adduction moment. Similar results were found for the relationship between knee adduction angular impulse and meniscus, cartilage and bone morphology.

CONCLUSIONS

Dynamic knee joint loading is significantly related to meniscus pathology and bone size, but not to cartilage thickness in women with OA.

An investigation of medication adherence to 5-aminosalicylic acid therapy in patients with ulcerative colitis, using self-report and urinary drug excretion measurements

BACKGROUND

Non-adherence to 5-aminosalicylic acid (5-ASA) medication can limit the established benefits of this therapy in ulcerative colitis (UC).

AIM

To determine rates and predictors of non-adherence to 5-ASA therapy in UC patients.

METHODS

Medication adherence was assessed using self-report data and urinary drug excretion measurements. Participants completed a study-specific questionnaire and two validated questionnaires: Beliefs about Medicine Questionnaire (BMQ)-Specific and Satisfaction with Information about Medicines Scale.

RESULTS

A total of 169 participants provided self-report adherence data; 151 also provided urine samples. Adherence rates were 111/151 (68%) according to self-report and 90/151 (60%) according to urine analysis, but the two measures were not correlated (chi(2) = 0.12, P = 0.725). Logistic regression identified a significant association between self-reported non-adherence and younger age [odds ratio (OR) for increased age 0.954, 95% confidence interval (CI) 0.932-0.976] and also doubts about personal need for medication (OR for BMQ - Specific Necessity scores 0.578, 95% CI 0.366-0.913). For non-adherence based on urine analysis, only South Asian ethnicity was independently associated with non-adherence (OR 2.940, 95% CI 1.303-6.638).

CONCLUSIONS

Our observations confirm the difficulty of accurately assessing medication adherence. Nonmodifiable (younger age, South Asian ethnicity) and potentially modifiable (medication beliefs) predictors of non-adherence were identified.

Identification of genetic markers associated with residual feed intake and meat quality traits in the pig

Residual feed intake (RFI) has become increasingly important and is being considered as a more reasonable approach to evaluate feed efficiency in livestock. However, the cost and technical difficulties in measuring this trait restrict the extensive adoption of RFI selection, and this makes marker assisted selection (MAS) a feasible tool. In addition, the effects on meat quality caused by low RFI selection have yet to be clarified. In this study, 11 SNPs from eight candidate genes were evaluated in a Yorkshire pig experimental population (n=169) consisting of a low RFI selection line and a randomly selected control line. Associations of these SNPs with RFI, growth rate, carcass composition, and meat quality measures including water holding capacity, pH at 2d postmortem, meat color and sensory traits were analyzed. The SNPs FTO p.Ala198Ala and TCF7L2 c.646+514A>G showed significant (P<0.05) and suggestively significant (P<0.1) associations with RFI, respectively. The MC4R SNP p.Asp298Asn was associated with backfat but it was not with ADG and meat quality attributes. Both SNPs within HNF1A were associated with intramuscular lipid content and sensory juiciness. The SNPs ACC1 c(*)384C>T and TCF7L2 c.646+514A>G were significantly (P<0.05) associated with ADG. The SNPs CTSZ p.Arg64Lys and TCF7L2 c.646+514A>G were associated with both visual scoring of meat color and the objective L-value measure of meat color. This study has identified potential genetic markers suitable for MAS in improving RFI, ADG, and meat color traits, but these associations need to be validated in other larger populations.

Efficacy and stability performance of traditional versus motion sensor-assisted strategies for FES standing

Standing by means of functional electrical stimulation (FES) after spinal cord injury is a topic widely reported in the neurorehabilitation literature. This practice commonly uses surface stimulation over the quadriceps muscle to evoke knee extension. To date, most FES neuroprostheses still operate without any artificial feedback, meaning that after a fatigue-driven knee buckle event, the stimulation amplitude or pulse width must be increased manually via button presses to re-establish knee-lock. This is often referred to as 'hand-controlled (HC) operation'. In an attempt to provide a safer, yet clinically practical approach, this study proposed two novel strategies to automate the control of knee extension based on the kinematic feedback of four miniaturised motion sensors. These strategies were compared to the traditional HC strategy on four individuals with complete paraplegia. The standing times observed over multiple trials were in general longer for the automated strategies when compared to HC (0.5-80%). With the automated strategies, three of the subjects tended to need less upper body support over a frame to maintain balance. A stability analysis based on centre of pressure (CoP) measurements also favoured the automated strategies. This analysis also revealed that although FES standing with the assistance of a frame was likely to be safe for the subjects, their stability was still inferior to that of able-bodied individuals. Overall, the unpredictability of knee buckle events could be more effectively controlled by automated FES strategies to re-establish knee-lock when compared to the traditional user-controlled approach, thus demonstrating the safety and clinical efficacy of an automated approach.

Immunity, trauma and the elderly

It is believed that an uncontrolled or poorly coordinated immune reaction can be stimulated by major trauma and be responsible for the development of the multiple organ dysfunction syndrome (MODS). The elderly have a reduced ability to mount an effective immune reaction with deficiencies involving both humoral and cellular aspects of immunity that involve poor function of both the stimulatory and immuno-suppressive sides of the immune process. However, there is currently no hard evidence that the excess mortality after major trauma in the elderly is associated with an impaired or excessive immune response. It is possible that their poor resistance to infection is important and immune modulated but the dominant factor in the excess mortality in the elderly population is probably associated with their lack of physiological reserve to respond to a major physiological challenge.

Electrically-evoked control of the swinging leg after spinal cord injury: open-loop or motion sensor-assisted control?

In paraplegics, gait can be restored by means of functional electrical stimulation (FES). Because the electrophysiological responses of the lower limbs to the neuromuscular stimulus are not completely deterministic, several stimulation strategies have been reported in an attempt to refine stepping motion. In open-loop (OL) systems, the electrical stimulation sequences applied over the leg muscles are often tuned for each patient in order to improve the quality of gait. Our aim was to contrast this traditional technique against variable stimulation sequences based on motion sensors (MS) data feedback. Both strategies were tested over 240 stepping trials in three complete paraplegics. In comparison to OL, which used a customised stimulation sequence for each subject, the same MS strategy was as functional for all three subjects. Despite MS producing a lower variability on step lengths, the toe clearances had a similar pattern of variability regardless of the strategy applied. Although the novel MS showed promising results, the reliability of OL was also demonstrated. Therefore, we still recommend the use of OL mainly due to its faster donning and doffing, since this is a matter of importance for the user acceptance of any rehabilitation systems.

Vascular endothelial growth factor as a survival factor for human islets: effect of immunosuppressive drugs

AIMS/HYPOTHESIS

Rapamycin, part of the immunosuppressive regimen of the Edmonton protocol, has been shown to inhibit vascular endothelial growth factor (VEGF) production and VEGF-mediated survival signalling in tumour cell lines. This study investigates the survival-promoting activities of VEGF in human islets and the effects of rapamycin on islet viability.

MATERIALS AND METHODS

Levels of VEGF and its receptors in isolated human islets and whole pancreas was determined by western blotting and immunostaining. Islet viability following VEGF or immunosuppressive drug treatment was determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Islet VEGF release was measured by ELISA. Mouse islets infected with an adenovirus expressing the gene for VEGF were transplanted syngeneically into streptozotocin-induced diabetic mice, with blood glucose levels measured three times per week.

RESULTS

Isolated human islets produced multiple isoforms of VEGF and VEGF receptors 1, 2 and 3 and the coreceptor neuropilin 1. Exogenous VEGF (10 ng/ml) prevented human islet death induced by serum starvation, which suggests that VEGF can act as a survival factor for human islets. Transplantation of mouse islets infected with a VEGF-expressing adenovirus in a syngeneic model, improved glycaemic control at day 1 post-transplantation (p < 0.05). Rapamycin at 10 and 100 ng/ml significantly reduced islet VEGF release (by 37 +/- 4% and 43 +/- 6%, respectively; p < 0.05) and at 100 ng/ml reduced islet viability (by 36 +/- 9%) and insulin release (by 47 +/- 7%, all vs vehicle-treated controls; p < 0.05). Tacrolimus had no effect on islet VEGF release or viability.

CONCLUSIONS/INTERPRETATION

Our data suggest that rapamycin may have deleterious effects on islet survival post-transplantation, both through a direct effect on islet viability and indirectly through blockade of VEGF-mediated revascularisation.

Inhalation of glutamic acid decarboxylase 65-derived peptides can protect against recurrent autoimmune but not alloimmune responses in the non-obese diabetic mouse

Systemic administration of islet-derived antigens has been shown to protect against diabetes in the non-obese diabetic (NOD) mouse by the induction of antigen-specific regulatory T cells. Bystander regulation to related and unrelated islet-derived antigens (intramolecular and intermolecular recognition) in this context is recognized. We tested if intranasal administration of glutamic acid decarboxylase 65 (GAD 65)-derived peptides could protect against both autoimmune and, through bystander regulation, alloimmune responses in a NOD mouse model. Spontaneously diabetic female NOD mice underwent islet transplantation from either C57Bl/6 or NOD islet donors. Islet recipients were treated with intranasal GAD 65-derived peptides or control (ovalbumin) peptide pre- and post-transplantation. In-vitro analysis of the effect of inhalation was defined using lymph node proliferation assays and supernatant analysis for cytokines. GAD 65-derived peptide inhalation resulted in significant protection against recurrent autoimmune disease, with the generation of an interleukin (IL)-10-producing immune phenotype in a syngeneic islet transplant model. This phenotype, however, was not robust enough to protect against alloimmune responses. Inhalation of GAD-derived peptides induces an immunoregulatory response that protects against recurrent autoimmune, but not alloimmune responses in the NOD mouse.

Degenerative meniscus tears and mobility impairment in women with knee osteoarthritis

OBJECTIVE

Meniscus tears are often presumed to be associated with a traumatic event, but they can also occur as a result of the cartilage degeneration process in osteoarthritis (OA). The aim of this paper is to describe the prevalence and clinical correlates of degenerative meniscus tears in women with knee OA.

METHOD

The subjects were women screened for a double-blind, sham-exercise controlled clinical trial for women over 40 years of age with OA in at least one knee, according to American College of Rheumatology (ACR) clinical criteria. The presence of meniscus tears was assessed via a 3T Intera (Philips Medical Systems) magnetic resonance image (MRI). Clinical examination included a history of arthritis onset and physical examination of the lower extremities. Physical assessments included body composition, muscle strength, walking endurance, gait velocity, and balance. In addition, pain and disability secondary to OA, physical self-efficacy, depressive symptoms, habitual physical activity level and quality of life were assessed via questionnaires.

RESULTS

Almost three-quarters (73%) of the 41 subjects had a medial, lateral, or bilateral meniscus tear by MRI. Walking endurance and balance performance were significantly impaired in subjects with a degenerative meniscus tear, compared to subjects without tears, despite similar OA duration, symptoms, and disability, body composition, and other clinical characteristics.

CONCLUSION

Meniscus tears, diagnosed by MRI, are very common in older women with knee OA, particularly in the medial compartment. These incidentally discovered tears are associated with clinically relevant impairments of balance and walking endurance relative to subjects without meniscus tears. The explanation for this association requires further study.

Positional effects and strand preference of RNA interference against hepatitis C virus target sequences

The hepatitis C virus (HCV) 3'-untranslated region (UTR) and negative-strand RNA sequences contribute cis-acting functions essential to viral RNA replication. Although efficient suppression of HCV replicon RNA in cell culture has been demonstrated with small interfering RNAs (siRNAs) directed against various sequences in the 5' UTR and coding regions, data regarding siRNA targeting of the 3' UTR have been lacking. Furthermore, it has not been definitively shown whether the active constructs, identified to date, exert their effect exclusively via suppression of the replicon positive strand, negative strand or some combination of both strands. In the present study, we assayed inhibitory activity of various siRNAs targeting the 3' UTR by transient transfection in a subgenomic replicon cell culture model. A survey of 13 candidate target sites in the 3'-UTR X sequence indicated a uniformly low activity of siRNA constructs against the steady-state level of replicon. In contrast, the majority of these same siRNAs exhibited high activity against HCV X sequences of either polarity when these targets were presented in the context of a mammalian polymerase II mRNA transcript. Transfection of siRNAs directed against other regions of the replicon revealed differences in the magnitude of inhibitory effects against positive-strand and negative-strand target sites. Strand preference of siRNA activity was further demonstrated through the introduction of base-pair-destabilizing mutations that promote strand-specific targeting. The results suggest that the HCV positive-strand 5' UTR and coding region are efficiently and directly targeted by siRNA, whereas the 3' UTR and the entire negative strand are relatively resistant to RNA interference.

Health-related behaviours as predictors of mortality and morbidity in Australian Aborigines

OBJECTIVE

To examine predictors of coronary heart disease (CHD) and all-cause mortality in Aboriginal Australians.

METHOD

In 1988-89, a survey of Western Australian Aborigines (256 women, 258 men) aged 15-88 years documented diet, alcohol and smoking habits. Linkage to mortality and hospital admissions to the end of 2002 provided longitudinal data for modelling of coronary heart disease endpoints and all-cause mortality using Cox regression.

RESULTS

Coronary heart disease risk increased with smoking (HR 2.62, 95% CI: 1.19, 5.75), consumption of processed meats >once/week (HR 2.21, 95% CI: 1.05, 4.63), eggs >twice/week (HR 2.59, 95% CI: 1.11, 6.04) and using spreads on bread (HR 3.14. 95% CI: 1.03, 9.61). All-cause mortality risk was lower with exercise >once/week (HR 0.51, 95% CI 0.26, 1.05), increased in ex-drinkers (HR 3.66, 95% CI: 1.08, 12.47), heavy drinkers (HR 5.26, 95% CI: 1.46, 7.52) and with consumption of take away foods >nine times/month (HR 1.78, 95% CI 0.96, 3.29). Greater alcohol intake, smoking and adverse dietary choices clustered in 53% of men and 56% of women and increased risk of coronary heart disease (HR 2.1, 95% CI: 1.1, 4.0) and all-cause mortality (HR 2.3, 95% CI: 1.2, 4.2).

CONCLUSION

Lifestyle in Aboriginal Australians predicts coronary heart disease and all-cause mortality. Clustering of adverse behaviours is common and increases risk of coronary heart disease and death.

Impact of diabetes on haemoglobin levels in renal disease

AIMS/HYPOTHESIS

Anaemia is a common complication of renal impairment. It has been suggested that renal failure secondary to diabetes is associated with more severe anaemia, but this has not been clearly substantiated in the published literature. To clarify this, we undertook a single centre, retrospective study to identify the impact of diabetes on anaemia associated with renal impairment.

MATERIALS AND METHODS

Information on clinical, biochemical and haematological parameters of 2,052 stable ambulatory patients attending a single tertiary referral renal unit was collected. The impact of diabetic kidney disease on haemoglobin levels at all degrees of renal impairment was studied by comparison with patients with non-diabetic kidney disease after correcting for other commonly associated variables that influence anaemia in patients with renal impairment.

RESULTS

Linear regression analysis showed lower haemoglobin in patients with diabetic kidney disease (p < 0.01). At chronic kidney disease (CKD) stages 3, 4 and 5, mean haemoglobin levels in patients with diabetic kidney disease compared with those in patients with non-diabetic kidney disease were 129.5 vs 136.9 g/l (p < 0.001), 120.5 vs 126.9 g/l (p < 0.001) and 107.1 vs 115.9 g/l (p < 0.01), respectively. At CKD stage 4 and 5 the two groups were comparable for ferritin, plasma intact parathyroid hormone levels, ACE inhibitor use and length of follow-up by a nephrologist.

CONCLUSIONS/INTERPRETATION

Diabetic kidney disease is associated with lower haemoglobin in comparison with non-diabetic kidney disease, especially at GFR <60 ml/min.

Metabolism of propionate by sheep liver. Stimulation of the mitochondrial rate by factors from the cell sap

1. The rate of metabolism of propionate by aged sheep-liver mitochondria in the presence of oxygen + carbon dioxide (95:5) was 5.0 (+/- s.e.m. 0.8) mumoles/mg. of mitochondrial N/hr. 2. When aged in the presence of the mitochondrial supernatant the rate was increased. Mitochondria from 0.33g. of liver, when combined with the corresponding mitochondrial supernatant from 0.08g. of liver, metabolized propionate at a rate of 11.4 (+/- s.e.m. 1.2) mumoles/mg. of mitochondrial N/hr. This rate is comparable with rates previously obtained with aged nuclear-free homogenates. 3. Two factors in the mitochondrial supernatant were detected, which when combined reproduced the effect of the fresh supernatant and prevented loss of activity on aging. One of these was non-diffusible and was recovered by fractionation of the dialysed mitochondrial supernatant with ammonium sulphate. The second factor was present in an ultrafiltrate of fresh mitochondrial supernatant and in boiled mitochondrial supernatant; it was isolated and identified as l(+)-glutamate. 4. The effect of the non-diffusible factor was due to protection of the mitochondria from the aging process, whereas glutamate served both in this capacity and as a direct stimulant of propionate metabolism at low concentration.

Over-expression of AMP-activated protein kinase impairs pancreatic {beta}-cell function in vivo

Treatment of type 1 diabetes by islet transplantation is currently limited by loss of functional beta-cell mass after transplantation. We investigated here whether adenovirus-mediated changes in AMP-activated protein kinase (AMPK) activity, previously shown to affect insulin secretion in vitro, might affect islet graft function in vivo. In isolated mouse and rat islets, insulin secretion stimulated by 17 (vs 3) mmol/l glucose was inhibited by 36.5% (P<0.01) and 43% (P<0.02) respectively after over-expression of constitutively-active AMPK- (AMPK CA) versus null (eGFP-expressing) viruses, and glucose oxidation was decreased by 38% (P<0.05) and 26.6% (P<0.05) respectively. Increases in apoptotic index (terminal deoxynucleotide transferase-mediated deoxyuridine trisphosphate biotin nick end-labelling) (TUNEL)) were also observed in AMPK CA- (22.8 +/- 3.6% TUNEL-positive cells, P<0.001), but not AMPK DN- (2.72 +/- 3.9%, positive cells, P=0.05) infected islets, versus null adenovirus-treated islets (0.68 +/- 0.36% positive cells). Correspondingly, transplantation of islets expressing AMPK CA into streptozotocin-diabetic C57 BL/6 mice improved glycaemic control less effectively than transplantation with either null (P<0.02) or AMPK-DN-infected (P<0.01) islets. We conclude that activation of AMPK inhibits beta-cell function in vivo and may represent a target for therapeutic intervention during islet transplantation.

Radiation exposure to the hands of orthopaedic surgeons: are we underestimating the risk?

INTRODUCTION

Previous studies reported that the radiation exposure to the hands of orthopaedic surgeons was far below the acceptable limit. However, the risk could have been underestimated as some factors were overlooked, namely monitoring trainees during average workload, placing dosimeters over the most susceptible locations, measuring the cumulative dosage of radiation and considering the dose limit for non-classified workers.

MATERIALS AND METHODS

We performed a prospective study in two centres to estimate the radiation dose to the hands of two consultant trauma surgeons and two trainees (one assisting and one operating) while performing 47 fluoroscopy-assisted procedures. We used validated thermoluminescent dosimeters (TLDs) rings and fingerstalls for monitoring the cumulative dosage.

RESULTS

Trainees were at higher risk while performing intramedullary nailing and during assistance. Higher radiation doses were recorded from dominant index fingers and particularly fingertips.

CONCLUSION

The risk of radiation exposure appears to be higher than previously reported. Fingertips are more susceptible to radiation exposure and should therefore be monitored in forthcoming studies.

Double-crush syndrome after acetabular fractures. A sign of poor prognosis

Injury to the sciatic nerve is one of the more serious complications of acetabular fracture and traumatic dislocation of the hip, both in the short and long term. We have reviewed prospectively patients, treated in our unit, for acetabular fractures who had concomitant injury to the sciatic nerve, with the aim of predicting the functional outcome after these injuries. Of 136 patients who underwent stabilisation of acetabular fractures, there were 27 (19.9%) with neurological injury. At initial presentation, 13 patients had a complete foot-drop, ten had weakness of the foot and four had burning pain and altered sensation over the dorsum of the foot. Serial electromyography (EMG) studies were performed and the degree of functional recovery was monitored using the grading system of the Medical Research Council. In nine patients with a foot-drop, there was evidence of a proximal acetabular (sciatic) and a distal knee (neck of fibula) nerve lesion, the double-crush syndrome. At the final follow-up, clinical examination and EMG studies showed full recovery in five of the ten patients with initial muscle weakness, and complete resolution in all four patients with sensory symptoms (burning pain and hyperaesthesia). There was improvement of functional capacity (motor and sensory) in two patients who presented initially with complete foot-drop. In the remaining 11 with foot-drop at presentation, including all nine with the double-crush lesion, there was no improvement in function at a mean follow-up of 4.3 years.

Unusual presentation of sciatica in a 14-year-old girl

The sciatic nerve can be compressed by a variety of causes, while intervertebral disc herniation is the most common cause of sciatica [Surg. Neurol. 46 (1996) 14], other documented causes include, infection, neoplasm, degenerative disease of a spine, congenital anomalies and traumatic posterior hip dislocation [BMJ 287 (1983) 157]. Sciatic neuropathy in children is uncommon. We present an unusual case of sciatic nerve compression in a 14-year-old-girl that was caused by an avulsion fracture of the ischial tuberosity. The compression was relieved by surgical excision of the avulsed ischial tuberosity.

The functional outcome of severe, open tibial fractures managed with early fixation and flap coverage

We studied the outcome and functional status of 33 patients with 34 severe open tibial fractures (Gustilo grade IIIb and IIIc). The treatment regime consisted of radical debridement, immediate bony stabilisation and early soft-tissue cover using a muscle flap (free or rotational). The review included standardised assessments of health-related quality of life (SF-36 and Euroqol) and measurement of the following parameters: gait, the use of walking aids, limb-length discrepancy, knee and ankle joint function, muscle wasting and the cosmetic appearance of the limb. Personal comments and overall patient satisfaction were also recorded. The mean follow-up was 46 months (15 to 80). There were 30 Gustilo grade IIIb fractures and and four grade IIIc fractures. Of the 33 patients, 29 had primary internal fixation and four, external fixation; 11 (34%) later required further surgery to achieve union and two needed bone transport procedures to reconstruct large segmental defects. The mean time to union was 41 weeks (12 to 104). Two patients (6.1%) developed deep infection; both resolved with treatment. The mean SF-36 physical and mental scores were 49 and 62 respectively. The mean state of health score for the Euroqol was 68. Patients with isolated tibial fractures had a better outcome than those with other associated injuries on both scoring systems. Knee stiffness was noted in seven patients (21%) and ankle stiffness in 19 (56%); 12 patients (41%) returned to work. Our results compare favourably with previous outcome measurements published for both limb salvage and amputation. All patients were pleased to have retained their limbs.

Distal femoral fractures: long-term outcome following stabilisation with the LISS

We studied 29 patients with distal femoral fractures stabilised using the less invasive stabilisation system (LISS). Four patients were excluded from the final follow-up (three deaths and one case of quadriplegia). The mean age of the remaining 25 patients (9 males and 16 females) was 60.9 years and the mean follow-up 18 months (range 12-24 months). Eleven patients were tertiary referrals from other hospitals (seven cases were referred due to failure of primary fixation). Overall, there were 12 cases of high-energy trauma (7 open fractures). According to the AO classification, there were 5 Type 33A, 2 Type 33B and 12 Type 33C fractures and 4 Type 32A, 1 Type 32B, 1 Type 32C fractures. Functional assessment was performed using the modified Hospital for Special Surgery (HSS) and the Schatzker and Lambert scores. The average time to union in 22 cases was 3.5 months (range 2-5 months). All of the acute cases united without the need for bone grafting. There were three out of seven cases of non-union in the salvage group still undergoing treatment. The overall result in the acute cases was good and in the salvage cases fair. While this is a small series of patients, our preliminary data indicate favourable results using the LISS in stabilising acute distal femoral fractures. However, when the LISS is used as a revision tool the results seem to be less satisfactory. The system appears to be user-friendly and no technical difficulties were encountered.

The GC–MS detection and characterization of reticuline as a marker of opium use

Reticuline (a precursor of opium alkaloids) was detected and characterised as its trimethylsilyl ethers, acetyl esters and methyl ethers by GC-EIMS and GC-CIMS in opium and the urine of opium users after hydrolysis by acid or beta-glucuronidase as coextractive of morphine. Because this compound cannot be detected in heroin and poppy seeds, it is suggested as a differentiating marker between opium and heroin use, opium and poppy seeds use, or opium and "pharmaceutical" codeine use in cases when opiate use has been confirmed by detection of morphine and codeine in the urine. As well as being a constituent of opium, reticuline in the urine of opium users may also result from the metabolic demethylation of the three other benzyltetrahydroisoquinoline opium alkaloids: codamine, laudanosine and laudanine.

Secondary structure and hybridization accessibility of the hepatitis C virus negative strand RNA 5'-terminus

The positive strand RNA genome of hepatitis C virus (HCV) is transcribed exclusively from a full-length cytoplasmic replication intermediate, the negative strand RNA. Despite this essential role in hepatocellular infection, the negative strand has not yet been subjected to extensive molecular characterization, and in comparison with the HCV genome and proteome, remains relatively unexplored as a target for antiviral therapy. The highly conserved negative strand terminal sequences, complementary to the positive strand 5'- and 3'-untranslated regions, are believed to contribute structural features essential for the initiation of positive strand synthesis and the maintenance of template integrity. We investigated the solution structure of the HCV negative strand 5'-terminal region by endoribonuclease mapping and thermodynamic modelling of RNA secondary structure. The enzymatic probing data are consistent with structural models featuring a large terminal stem loop (SL), which constitutes a mirror image of the complementary 3'-X region SL I structure. Nucleotide positions within the negative strand accessible to hybridization were mapped by RNase H digestion in the presence of combinatorial oligonucleotide libraries. The hybridization data further support the existence of a terminal SL, and reveal target sites within the negative strand 5'-terminus which may be susceptible to antisense-mediated inhibition.

The GC–MS detection and characterization of reticuline as a marker of opium use

Reticuline (a precursor of opium alkaloids) was detected and characterised as its trimethylsilyl ethers, acetyl esters and methyl ethers by GC-EIMS and GC-CIMS in opium and the urine of opium users after hydrolysis by acid or beta-glucuronidase as coextractive of morphine. Because this compound cannot be detected in heroin and poppy seeds, it is suggested as a differentiating marker between opium and heroin use, opium and poppy seeds use, or opium and "pharmaceutical" codeine use in cases when opiate use has been confirmed by detection of morphine and codeine in the urine. As well as being a constituent of opium, reticuline in the urine of opium users may also result from the metabolic demethylation of the three other benzyltetrahydroisoquinoline opium alkaloids: codamine, laudanosine and laudanine.

Structure-based design of hepatitis C virus inhibitors

The limitations of current treatment for chronic hepatitis C virus (HCV) infection have prompted the development of novel therapeutic strategies targeting events specific to viral replication. Over the past decade, advances in the study of HCV molecular biology have led to the identification of cis-acting RNA sequences and viral enzymatic activities which present attractive targets for inhibition. High-resolution, three-dimensional structures of the HCV serine protease, helicase and RNA-dependent RNA polymerase have been determined through X-ray crystallographic studies. More recently, solution structures of these proteins and the HCV internal ribosome entry site have been evaluated by nuclear magnetic resonance spectroscopy and electron microscopy. Mutational analysis and structural characterization of these macromolecules in complex with bound substrates, cofactors and inhibitors has further defined the various electrochemical interactions which mediate protein-protein, protein-RNA and other intermolecular contacts. This review will discuss the available structural data with respect to the rational design of HCV enzyme inhibitors and the development of antisense-based therapeutic strategies, such as RNA interference.

Segmental tibial fractures: an assessment of procedures in 27 cases

Twenty-seven patients (two women) with segmental tibial fractures (19 open) were treated in our institution with a mean age of 38.9 years (range 22-67 years) and a mean Injury Severity Score of 11.5 (9-34). Sixteen fractures were stabilised initially with an interlocking nail, seven with an external fixator, one with a hybrid external fixator, two cases were plated and one was treated in plaster. The mean size of the segment was 11.5 cm (range 4-20 cm). Soft tissue coverage was required in 17 cases. There were three cases of compartment syndrome, six cases of superficial infection and four deep infection cases (two of which required amputation). In four cases, excision of the non-viable segment was necessary. Overall, 13 patients were subjected to a second operative procedure (OP) (four external fixators were replaced with the AO solid tibial nail, two Ilizarov bone transports following excision of the dead bone segment, 2 below knee amputations, 3 exchange reamed nailings, 1 LISS plate application for stability and 1 ring fixator for compression of a fracture). Five patients underwent third procedure (two Ilizarov for bone transport, two exchange nailing, and one bone grafting). The mean time to union of the proximal segment was 38.8 weeks (range 10-78 weeks) and 41.4 weeks (range 12-65 weeks) for the distal segment, respectively. The treatment of segmental tibial fractures poses many problems to the surgeon due to the precarious blood supply of the intermediate segment. The risk of non-union delayed union, infection and additional procedures is high as seen in this series of patients.

Review: systemic effects of femoral nailing: from Küntscher to the immune reactivity era

Intramedullary nailing is the preferred treatment for stabilizing femoral diaphyseal fractures. Despite the superior biomechanical advantages over other implants, its use especially in some selected groups of patients, has been questioned because of possible harmful systemic effects of intramedullary reaming. The lung seems to be the primary target for fat embolization and for mediated effects by inflammatory reactions. The latter are initiated in the immediate aftermath after injury, and femoral nailing can amplify these responses. The role of reaming in the context of early femoral fracture fixation in the patient experiencing trauma is debatable. This review article focuses on the evidence that has emerged during the past century regarding the systemic effects of femoral nailing.

Fit analysis in latent trait measurement models

The analysis of fit, whether viewed from the prospective of the fit of the data to the measurement model, or the fit of the measurement model to the data, is an important part of using latent trait models. In the case of the Rasch model, all of the desirable characteristics of the model (interval item and person measures, asymptotic standard errors, parameter invariance across subsets of persons or items, to name a few) are predicated on the requirement that the data fit the model. To the extent that the data do not fit the model, these properties hold to a lesser degree. The analysis of fit is of primary importance if the interpretation of the calibration results is to be useful. This article explores the nature of fit and provides a historical overview of fit indices. It then focuses on a particular family of fit indices that are based on the Pearsonian chi-square approach to fit, in an attempt to show why it is necessary to use a family of standardized fit indices to completely understand the relationship between the data and the model.

Functional handgrip test to determine the coefficient of static friction at the hand/handle interface

The aim was to devise a method of measuring friction at the hand/handle interface during a functional handgrip task. No descriptions of methods of this kind was found in the literature. An indirect technique of measuring normal grip force was employed to determine friction at the hand/handle interface while performing a functional handgrip action with a grabrail. The coefficient of static friction was calculated between palmar skin (dry, wet, and soapy hands) and five grabrail materials (stainless steel, powder-coated steel, chrome, textured aluminium and knurled steel). Thirty subjects participated (15 female, 15 male), who were aged from 17 to 45 years with a mean age of 30 years. Knurled steel produced a significantly larger mean coefficient of static friction than chrome, powder-coated steel and stainless steel, and textured aluminium had a significantly larger coefficient of static friction than stainless steel. Soapy hands produced the lowest mean coefficients (0.46+/-0.04), significantly less then dry (1.72+/-0.16, p <0.001) and wet hands (1.42+/-0.16, p <0.001). This study has demonstrated the influence of grabrail material and palmar skin treatments on static friction at the hand/handle interface. The use of a functional test that incorporates an indirect determination of normal handgrip force has provided a quantitative method of observing stability at the hand/handle interface.

Injury patterns associated with mortality following motorcycle crashes

All patients involved in motorcycle crashes admitted to various hospitals in the Yorkshire region of UK between January 1993 and December 1999 were retrospectively reviewed to identify the factors that are likely to predict a reduced survival. Of the 1239 patients requiring hospital admission, 74 died. The probability of reduced survival was estimated by a logistic regression model using independent variables such as head injury, thoracic trauma, abdominal injury, spinal injury and pelvic fracture and a compound variable of pelvic fracture combined with a long bone fracture. The odds ratio for head injury was 0.349, chest injury 0.39, abdominal injury 0.42, and the compound variable (pelvis plus a long bone fracture) 0.576. The mean injury severity score (ISS) in the fatal group was 35.96 compared to 12.2 in the group that survived (P<0.01). There was a significant difference in the Glasgow coma scale (GCS) between patients wearing a helmet and those that did not wear any protective headgear (P=0.0007). Head injury followed by chest and abdominal trauma were found to predict a reduced survival rate. Use of helmets should continue to be compulsory. Chest and abdominal injuries should be diagnosed and treated early to reduce mortality.

An investigation of gender differences in the components influencing the difficulty of spatial ability items

This study examines the role that gender differences play in the determination of the components influencing the difficulty of spatial ability items. Considerable research has examined the role of gender differences in spatial abilities, with sometimes contradictory findings. In general, the findings show that males tend to outperform females on spatial ability items. Other research has focused on determining the components of items that contribute to their difficulty. This research has usually been based on mixed-gender populations, however. The present study attempts to determine if gender influences the extent to which different components contribute to the difficulty of items. The results indicate that component difficulties show very little variation across gender. This finding supports the notion that any differences in raw scores observed for males and females are not due to differences in the manner in which males and females process spatial information or solve spatial ability items.

Friction burns within the tibia during reaming. Are they affected by the use of a tourniquet?

We have carried out a prospective, randomised trial to measure the rise of temperature during reaming of the tibia before intramedullary nailing. We studied 34 patients with a mean age of 35.1 years (18 to 63) and mean injury severity score of 10 (9 to 13). The patients were randomised into two groups: group 1 included 18 patients whose procedure was undertaken without a tourniquet and group 2, 16 patients in whom a tourniquet was used. The temperature in the bone was measured directly by two thermocouples inserted into the cortical bone near the isthmus of the tibial diaphysis. Reaming was carried out to at least 1.5 mm above the required diameter of the nail. Blood loss was assessed by recording the preoperative and postoperative haemoglobin (Hb) level. The minimum clinical follow-up was six months. In group 1 (no tourniquet), the mean Hb dropped 2.8 g/dl from 14.3 +/- 1.02 g/dl to 11.5 +/- 1.04 g/dl (p = 0.0001), whereas with the tourniquet, the mean decrease was 1.3 g/dl from 14 +/- 1 g/dl to 12.7 +/- 1.3 g/dl (p = 0.007). This difference was not statistically significant. The mean initial tibial temperature was 35.6 degrees C (SD 0.6) and rose with reaming to levels between 36.3 degrees C and 51.6 degrees C. The highest temperatures were obtained with the largest reamers (11 and 12 mm, p = 0.0001) and the most rapid rise with the smallest diameters of medullary canal (8 or 9 mm). The rise of temperature was transient (20 s). We were unable to identify any effect of the use of a tourniquet on the temperature achieved. Reamed intramedullary tibial nailing induces a transient elevation of temperature which is directly related to the amount of reaming.