Comparison of kidney transplant outcomes in HLA compatible and incompatible transplantation: a national cohort study

BACKGROUND

Reports of HLA incompatible (HLAi) kidney transplant outcomes are inconclusive, especially in the context of lower level Donor Specific Antibodies (DSA).

METHODS

Multi-centre national cohort study of HLAi kidney transplant recipients matched in 1:2 ratio with HLA compatible (HLAc) kidney transplant recipients. HLAi defined as DSA identified by Luminex. Antibody mediated rejection (AMR) and transplant-survival were analysed using Kaplan-Meier plots. Propensity score (PS) matching was used to compare recipient and transplant survival between groups.

RESULTS

We included 61 HLAi and 122 HLAc recipients; mean age 46 years; 60% female. MFI_T0 : 3327 (IQR 1352 - 6458), 23 (38%) were Flow cytometry crossmatch positive (FC-XM_POS) . DSA_POS /FC-XM_POS transplantation carried an increased risk of AMR at 1 year (52%) compared to DSA_POS /FC-XM_NEG (27%) and HLAc (0%). Unadjusted death censored graft loss at 3 years was 13% (HLAi) and 8% (HLAc). Three-year patient survival was 95% in HLAc, 84% in DSA_POS /FC-XM_NEG and 69% in DSA_POS /FC-XM_POS recipients; 58% of HLAi deaths were infection-related. HLA incompatibility was associated with a decreased 3-year survival in our PS-matched cohort.

CONCLUSION

In kidney transplantation, DSA and positive FC-XM carries an increased risk of AMR. Despite inferior transplant and survival outcomes compared to HLAc transplantation, it remains a realistic option for highly sensitised patients facing prolonged waiting times and reduced survival on dialysis.

Perfusate Composition and Duration of Ex-Vivo Normothermic Perfusion in Kidney Transplantation: A Systematic Review

Ex-vivo normothermic perfusion (EVNP) is an emerging strategy in kidney preservation that enables resuscitation and viability assessment under pseudo-physiological conditions prior to transplantation. The optimal perfusate composition and duration, however, remain undefined. A systematic literature search (Embase; Medline; Scopus; and BIOSIS Previews) was conducted. We identified 1,811 unique articles dating from January 1956 to July 2021, from which 24 studies were deemed eligible for qualitative analysis. The perfusate commonly used in clinical practice consisted of leukocyte-depleted, packed red blood cells suspended in Ringer’s lactate solution with Mannitol, dexamethasone, heparin, sodium bicarbonate and a specific nutrient solution supplemented with insulin, glucose, multivitamins and vasodilators. There is increasing support in preclinical studies for non-blood cell-based perfusates, including Steen solution, synthetic haem-based oxygen carriers and acellular perfusates with supraphysiological carbogen mixtures that support adequate oxygenation whilst also enabling gradual rewarming. Extended durations of perfusion (up to 24 h) were also feasible in animal models. Direct comparison between studies was not possible due to study heterogeneity. Current evidence demonstrates safety with the aforementioned widely used protocol, however, extracellular base solutions with adequate oxygenation, supplemented with nutrient and metabolic substrates, show promise by providing a suitable environment for prolonged preservation and resuscitation.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021231381, identifier PROSPERO 2021 CRD42021231381

The New UK National Kidney Allocation Scheme With Maximized "R4-D4" Kidney Transplants: Better Patient-to-Graft Longevity Matching May Be at the Cost of More Resources

OBJECTIVES

A new kidney matching scheme for allocation of deceased donor kidneys for transplantation was introduced in the United Kingdom in September 2019. Donors and recipients are stratified into quartiles derived from demographic and retrieval indices associated with risk of adverse outcome. We present data on 2 years of transplants, with the aim of understanding the potential impacts ofthe scheme on patient/transplant outcomes, hospitalization, and resource utilization.

MATERIALS AND METHODS

All deceased donortransplants from 2015 and 2016 were reclassified using the risk quartiles (D1-D4 for donor and R1-R4 for recipient, where 4 is highestrisk). Inpatientlength of stay, kidney function defined by estimated glomerular rate at 1 year, and patient survival data were collected.

RESULTS

Of the 195 deceased donor transplants analyzed, 144 recipients (73.4%) were in the highest risk R4 category, including 55 with R4-D4 combination (28.1%). Recipients in the R4 category had longer index admissions (mean of 12.4 vs 8.1 days for R1-R3; P = .002) and higher subsequent admission rates 90 days posttransplant(185.7 vs 122.7/1000 patient days for R1-R3; P < .001). Kidney transplant function at 1 year was lower for grafts categorized as D4 (mean estimated glomerular filtration rate of 35.7 vs 54.8 mL/min/1.73 m2 for D1-D3; P < .001). However, survival for R4 recipients with D4 kidneys was not significantly differentfrom R4 recipients with D1 to D3 kidneys (4-year patient survival rate with R4-D4 combination was 90.9%).

CONCLUSIONS

The principles ofthe allocation scheme in matching graft and patient survival were already largely being observed (matching higher risk deceased donor kidneys to higher risk recipients). However, an increase in D4 proportions in the R4 group may be associated with longer hospitalization posttransplant. Consideration should be given to mitigation strategies to address this. Despite poorer graft function, patient survival appears satisfactory.

Viability assessment and utilization of declined donor kidneys with rhabdomyolysis using ex vivo normothermic perfusion without preimplantation biopsy

The role of ex vivo normothermic perfusion (EVNP) in both organ viability assessment and reconditioning is increasingly being demonstrated. We report the use of this emerging technology to facilitate the transplantation of a pair of donor kidneys with severe acute kidney injury (AKI) secondary to rhabdomyolysis. Donor creatinine was 10.18 mg/dl with protein (30 mg/dl) present in urinalysis. Both kidneys were declined by all other transplantation units and subsequently accepted by our unit. The first kidney was perfused with red cell-based perfusate at 37°C for 75 min, mean renal blood flow was 110 ml/min/100 g and produced 85 ml of urine. Having demonstrated favorable macroscopic appearance and urine output, the kidney was transplanted into a 61-year-old peritoneal dialysis dependent without complication. Given the reassuring information from the first kidney provided by EVNP, the second kidney was not perfused with EVNP and was directly implanted to a 64-year-old patient. The first kidney achieved primary function and the second functioned well after delayed graft function. Recipient eGFR have stabilized at 88.5 and 55.3, respectively (ml/min/1.73 m² ), at 2 months posttransplant.

The impact of age on patient tolerance of mycophenolate following kidney transplantation

BACKGROUND

In Scotland, standard maintenance immunosuppression following kidney transplantation consists of mycophenolate (MPA), tacrolimus and prednisolone irrespective of recipient age. We analyzed the tolerability of this immunosuppression regimen and the association with transplant outcomes.

METHODS

A national, multicentre retrospective analysis of patients transplanted in 2015 and 2016, comparing graft function, acute rejection, significant infection rates and immunosuppression dosing between patients aged 18 and 59 years (Group 1) and ≥60 years (Group 2).

RESULTS

Of the 490 patients, 26% were aged ≥60 years. Acute rejection (AR) rates at 1 year were 15% and 11% in Groups 1 and 2, respectively. Full-dose MPA was poorly tolerated with 53% in Group 1 and 77% in Group 2 requiring dose reduction or cessation. Female gender and age ≥60 years were independent predictors for MPA dose changes. One year following MPA dose reduction, AR risk was low (5%) in Group 2, however, those remaining on full dose MPA had a 79% increased rate of serious infections.

CONCLUSION

The majority of renal transplant recipients aged ≥60 fail to tolerate full-dose MPA. In this group, MPA dose reduction is associated with low rejection rates, but full-dose MPA is associated with high infection rates. We suggest that a tailored approach to immunosuppression in elderly recipients incorporating lower doses of MPA may be appropriate.

Characterizing the early inflammatory contribution of the donor kidney following reperfusion

Background

Donor kidneys contain a large reservoir of passenger leucocytes that contribute to acute rejection via direct alloantigen presentation and pro-inflammatory cytokine secretion. However, the early contribution of these cells following revascularization has not previously been described. We performed a secondary, high-volume preservation flush following cold storage to characterize the inflammatory contribution of the donor kidney upon reperfusion.

Methods

Porcine kidneys were retrieved using a protocol analogous to current UK clinical practice. Following 2 h of cold static preservation, kidneys underwent a secondary flush with Ringer's solution. The venous effluent was collected and leucocytes phenotyped via flow cytometry. Inflammatory mediators, including cytokines and cell-free DNA, were then assessed to determine the inflammatory contribution of the donor kidney.

Results

Upon reperfusion, a significant population of donor-derived CD45 +  leucocytes mobilized from the renal vasculature via the renal vein [mean 4.738 × 10 8  (SD 1.348 × 10 8 )]. Within this population, T cells were dominant, representing >60% of the leucocyte repertoire. Granulocytes, monocytes and natural killer cells were also identified, but in comparatively lower numbers. Significant concentrations of cytokines and cell-free DNA were also eluted upon reperfusion.

Conclusions

The donor kidney contains a significant immune load that rapidly mobilizes following reperfusion. Performing a secondary preservation flush prior to implantation may reduce this inflammatory burden via diversion of donor leucocytes and inflammatory mediators from entry into the recipient circulation. This may modulate direct presentation and reduce the inflammatory contribution of the donor kidney following transplantation.

Deleterious effects of phosphate on vascular and endothelial function via disruption to the nitric oxide pathway

Background

Hyperphosphataemia is an independent risk factor for accelerated cardiovascular disease in chronic kidney disease (CKD), although the mechanism for this is poorly understood. We investigated the effects of sustained exposure to a high-phosphate environment on endothelial function in cellular and preclinical models, as well as in human subjects.

Methods

Resistance vessels from rats and humans (± CKD) were incubated in a normal (1.18 mM) or high (2.5 mM) phosphate concentration solution and cells were cultured in normal- (0.5 mM) or high-phosphate (3 mM) concentration media. A single-blind crossover study was performed in healthy volunteers, receiving phosphate supplements or a phosphate binder (lanthanum), and endothelial function measured was by flow-mediated dilatation.

Results

Endothelium-dependent vasodilatation was impaired when resistance vessels were exposed to high phosphate; this could be reversed in the presence of a phosphodiesterase-5-inhibitor. Vessels from patients with CKD relaxed normally when incubated in normal-phosphate conditions, suggesting that the detrimental effects of phosphate may be reversible. Exposure to high-phosphate disrupted the whole nitric oxide pathway with reduced nitric oxide and cyclic guanosine monophosphate production and total and phospho endothelial nitric oxide synthase expression. In humans, endothelial function was reduced by chronic phosphate loading independent of serum phosphate, but was associated with higher urinary phosphate excretion and serum fibroblast growth factor 23.

Conclusions

These directly detrimental effects of phosphate, independent of other factors in the uraemic environment, may explain the increased cardiovascular risk associated with phosphate in CKD.

Ex Vivo Normothermic Perfusion Induces Donor-Derived Leukocyte Mobilization and Removal Prior to Renal Transplantation

Introduction

Ex vivo normothermic perfusion offers an alternative method of organ preservation, allowing donor kidneys to be reanimated and evaluated prior to transplantation. Beyond preservation, it can be used to characterize the immunological contribution of the donor kidney in isolation. Furthermore, it has the potential to be used as an immunomodulatory strategy to manipulate donor kidneys prior to transplantation.

Methods

Explanted porcine kidneys underwent 6 hours of perfusion. Sequential perfusate samples were collected and leukocytes characterized via flow cytometry. An inflammatory profile was generated via cytokine quantification. Cell-free DNA was also determined as markers of cell death.

Results

All kidneys functioned within normal parameters and met the criteria for transplantation at the end of perfusion. Throughout perfusion there were continuous increases in pro-inflammatory cytokines, including large concentrations of interferon-γ, suggesting that perfusion drives a significant inflammatory response. Increasing concentrations in cell-free DNA were also observed, suggesting cell death. During perfusion there was a marked cellular diapedesis of T cells, B cells, natural killer (NK) cells, and monocytes from the kidney into the circuit. Minor populations of granulocytes and macrophages were also detected.

Discussion

We demonstrate that ex vivo normothermic perfusion initiates an inflammatory cytokine storm and release of mitochondrial and genomic DNA. This is likely to be responsible for immune cell activation and mobilization into the circuit prior to transplantation. Interestingly this did not have an impact on renal function. These data therefore suggest that normothermic perfusion can be used to immunodeplete and to saturate the pro-inflammatory capacity of donor kidneys prior to transplantation.

Predictors of sustained arteriovenous access use for haemodialysis

BACKGROUND

Guidelines encourage early arteriovenous (AV) fistula (AVF) planning for haemodialysis (HD). The aim of this study was to estimate the likelihood of sustained AV access use taking into account age, sex, comorbidity, anatomical site of first AVF and, for pre-dialysis patients, eGFR and proteinuria.

METHODS

1,092 patients attending our centre who had AVF as their first AV access procedure between January 1, 2000 and August 23, 2012 were identified from the electronic patient record. The primary end-point was time to first sustained AV access use, defined as use of any AV access for a minimum of 30 consecutive HD sessions.

RESULTS

52.9% (n = 578) of the patients ultimately achieved sustained AV access use. The main reasons for AV access non-use were AVF failure to mature and death. The 3-year Kaplan-Meier probability of sustained AV access use was 68.8% for those not on renal replacement therapy (RRT) (n = 688) and 74.2% for those already on RRT (n = 404) at the time of first AVF. By multivariate analysis in patients not on RRT, male sex (HR 2.22; p < 0.001), uPCR (HR 1.03; p = 0.03) and eGFR (hazard ratio, HR 0.85; p < 0.001) were independent predictors of AV access use. In patients already on RRT, age (HR 0.98; p < 0.001) and peripheral vascular disease (HR 0.48; p = 0.02) were independent predictors of AV access use.

CONCLUSION

Our data suggest that refinement of the current guideline for timing of AV access creation in planning RRT is justified to take into account individual factors that contribute to the likelihood of technical success and clinical need.

Hand-assisted laparoscopic living donor nephrectomy: initial Glasgow experience

AIMS

The study presents the early results of hand-assisted laparoscopic living donor nephrectomy (HALDN) carried out in West of Scotland from June 2009 to October 2010.

METHODS

The first 20 HALDN procedures carried out in our unit are presented. The outcomes reported are warm ischaemia time, operative time, delayed graft function, recipient renal function and one-month morbidity and mortality of donor and recipient. SPSS 15.0 was used for statistical analysis.

RESULTS

The mean age of the donors was 44 ± 10 years, predominantly females (n = 13), median operative time 135 ± 33 min and warm ischaemia time 41 ± 16 s. The length of the incision used was 65 mm in all cases. Duration of hospital stay was 5 ± 1 days. Patient mortality was 0 and morbidity minimal with two donors developing minor wound infection and no other clinically significant postoperative morbidity. Among the recipients, 18/20 (90%) transplants worked primarily with two delayed graft functions, one due to early surgical complications in a small paediatric recipient and one due to recipient renal artery thrombosis.

CONCLUSION

HALDN is safe and associated with minimal morbidity; further analysis aims to confirm excellent cosmetic results and quick return to activity compared with the standard open nephrectomy technique.

Pyogenic ventriculitis following enteral bacterial translocation in a patient with small bowel obstruction

The authors present a rare case of ventriculitis secondary to cerebro spinal fluid (CSF) colonization with Escherichia coli species in a 65-year-old woman. Passage of bacterial organisms from the lumen of the gastrointestinal tract to the bloodstream or lymphatic tissue is known as translocation. Once in the bloodstream, particular bacteria are able to cross the blood-brain barrier and migrate to CSF. Elective abdominal surgery, intestinal obstruction, colorectal cancer, ischaemic reperfusion injury and pancreatitis have all increased the risk of this phenomenon. This account highlights particular events in presentation and management of such a case, followed by a brief literature review.

Single-center experience of encapsulating peritoneal sclerosis in patients on peritoneal dialysis for end-stage renal failure

BACKGROUND

Encapsulating peritoneal sclerosis (EPS) is a rare but serious complication in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) or automated peritoneal dialysis (APD). It is characterized by a progressive, intra-abdominal, inflammatory process resulting in sheets of fibrous tissue that cover, bind, and constrict the viscera, thereby compromising the motility and function of the bowel. Although recent therapeutic approaches have been reported with variable success, the ability to detect reliably at an early stage patients at risk for EPS would be beneficial and allow treatment standardization. The aim of this study was to evaluate the clinical features of EPS and identify possible risk factors for its development in CAPD and APD patients.

METHODS

This was a review of all cases of EPS in a single center over the last 5 years.

RESULTS

There were 810 CAPD and APD patients, managed in our program over this period. We identified 27 cases of EPS, giving an overall of 3.3% in this population. The mean duration of CAPD before diagnosis of EPS was 72.6 +/- 39.7 months (range 16-172). Sixteen cases required surgical treatment and were classified as severe; others were treated conservatively (mild to moderate group). Ten patients received tamoxifen treatment with apparent benefit. The overall mortality rate was 29.6%. Eight patients from the severe group and the entire moderate group survived on hemodialysis or transplantation at 48.71 and 27.63 months follow-up, respectively. Peritonitis rates were not different between the 2 groups and peritoneal history was unremarkable compared to overall peritonitis rates in the unit. Data on small solute transport were not available in all patients in this retrospective analysis.

CONCLUSION

EPS is a serious, life-threatening complication of CAPD. Most cases had PD duration of more than 4 years. Careful monitoring by CT scans of the peritoneal membrane in patients beyond 5 years, and early catheter removal in patients with peritoneal thickening should be considered for long-term CAPD patients. Treatment with tamoxifen may be of benefit in these patients.

Laryngopharyngeal pH measurement

OBJECTIVES

Most emergency department (ED) intubations are to prevent gastric contents aspiration. The incidence of aspiration is unknown and intubation has complications. Balancing these risks requires an idea of the incidence of aspiration. This study assessed one technique for investigating the aspiration risk in ED patients. Cricoid pressure is used to reduce this risk and the technique may also examine this manoeuvre.

METHODS

Cohorts of unconscious adult ED and elective surgical patients were recruited. The posterior pharyngeal wall pH was measured immediately before and after intubation. Pharyngeal pH was used to indicate risk of aspiration, and pH change to assess the efficacy of cricoid pressure.

RESULTS

Eight ED and 48 control patients were recruited. In the ED cohort, pH ranged from 6.0 to 8.0 before intubation and 4.7 to 8.0 after intubation: a mean decrease of 0.3 (95% CI 1.5 decrease to 0.9 increase). In the control cohort pH ranged from 5.8 to 8.0 before intubation and 6.0 to 8.0 after intubation: a mean increase of 0.4 (95% CI 0.1 to 0.6 increase).

CONCLUSIONS

This is a simple, cheap, and repeatable technique for assessing aspiration risk in emergency intubations. A larger study is required to assess the efficacy of cricoid pressure.

Bronchoscopic removal of an inhaled, sharp, foreign body: an unusual complication

A case is reported in which an inhaled sewing needle, stuck fast in the trachea, became displaced through the tracheal wall during attempted removal via flexible bronchoscopy. The inherent risks and pitfalls of this procedure are highlighted.

Should UK emergency physicians undertake diagnostic ultrasound examinations?

From the published evidence there is no doubt that emergency physicians in America can undertake focused ultrasound examinations and that, by extrapolation, this would also be the case for UK emergency physicians. If this skill is to become part of the diagnostic armamentarium of the emergency physician, however, it needs to be demonstrated to be cost effective compared with the alternatives already available to the hospital. Trials to test for this benefit should adopt a hospital and not an emergency department perspective if the results are to influence health policy and specialty training.

Persistent "haematoma"

Images

Clearing the cervical spine of adult victims of trauma

Images

Point of care testing in the accident and emergency department: a cost analysis and exploration of financial incentives to use the technology within the hospital

OBJECTIVES

To compare the costs of current arrangements for testing emergency blood samples from patients attending an accident and emergency (A&E) department in a large teaching hospital in England with point of care testing (POCT).

METHODS

Estimates were made of the fixed and variable costs of two options: a supplemental option, in which POCT was introduced to A&E only; and a replacement option, in which POCT was introduced to A&E and the intensive therapy unit (ITU), thereby entirely replacing an existing process.

RESULTS

For the supplemental option, current arrangements cost 68,466 Pounds in total per year; average costs per test were 5.53 Pounds (venous in the central laboratory) and 3.60 Pounds (arterial on the ITU). Introducing POCT would increase total hospital costs by 35,929 Pounds, and average costs per test would be 5.32 Pounds (venous) and 4.28 Pounds (arterial). For the replacement option, current arrangements cost 132,630 Pounds in total, and average cost per test (for all tests) was 4.06 Pounds. Introducing POCT would make hospital savings ranging from 8332 Pounds to 20,000 Pounds, and average cost per test would be 3.78 Pounds.

CONCLUSIONS

Introducing POCT results in lower average costs per test. The supplemental option will result in significantly increased costs to the hospital. The replacement option can lead to significant savings. The internal cross-charging arrangements between departments that exist in this hospital may mean that supplemental implementation of POCT could be potentially 'profitable' for the A&E department, but would result in higher expenditure for the hospital as a whole.

Meiosis: step-by-step through sporulation

A transcription factor, Ndt80p, has been identified that has a critical role in the pathway that controls meiosis--sporulation--in budding yeast. Ndt80p coordinately controls genes that mediate spore formation and progression through the two meiotic divisions; it may also be a target of a checkpoint control.

The S. cerevisiae nitrogen starvation-induced Yvh1p and Ptp2p phosphatases play a role in control of sporulation

Starvation for nitrogen in the absence of a fermentable carbon source causes diploid Saccharomyces cerevisiae cells to leave vegetative growth, enter meiosis, and sporulare; the former nutritional condition also induces expression of the YVH1 gene that encodes a protein phosphatase. This correlation prompted us to determine whether the Yvh1p phosphatase was a participant in the network that controls the onset of meiosis and sporulation. We found that expression of the IME2 gene, encoding a protein kinase homologue required for meiosis- and sporulation-specific gene expression, is decreased in a yvh1 disrupted strain. We also observed a decrease, albeit a smaller one, in the expression of IME1 which encodes an activator protein required for IME2 expression. Under identical experimental conditions, expression of the MCKI and IME4 genes (which promote sporulation but do not require Ime1p for expression) was not affected. These results demonstrate the specificity of the yvh1 disruption phenotype. They suggest that decreased steady-state levels of IME1 and IME2 mRNA were not merely the result of non-specific adverse affects on nucleic acid metabolism caused by the yvh1 disruption. Sporulation of a homozygous yvh1 disruption mutant was delayed and less efficient overall compared to an isogenic wild-type strain, a result which correlates with decreased IME1 and IME2 gene expression. We also observed that expression of the PTP2 tyrosine phosphatase gene (a negative regulator of the osmosensing MAP kinase cascade), but not the PTP1 gene (also encoding a tyrosine phosphatase) was induced by nitrogen-starvation. Although disruption of PTP2 alone did not demonstrably affect sporulation or IME2 gene expression, sporulation was decreased more in a yvh1, ptp2 double mutant than in a yvh1 single mutant; it was nearly abolished in the double mutant. These data suggest that the YVH1 and PTP2 encoded phosphatases likely participate in the control network regulating meiosis and sporulation. Expression of YVH1 and PTP2 was not affected by nitrogen source quality (asparagine compared to proline) suggesting that nitrogen starvation-induced YVH1 and PTP2 expression and sensitivity to nitrogen catabolite repression are on two different branches of the nitrogen regulatory network.

Changes in stroke distance in response to haemorrhage in a swine model

OBJECTIVE

To determine, using an animal model of blood loss, (1) if stroke distance, derived non-invasively from the time integral of the maximum velocity of red cells in the aorta, changed to a greater extent than heart rate and mean arterial pressure (MAP), which are recognised to be unreliable indicators of blood loss; (2) if changes in stroke distance reflected changes in stroke volume derived from thermodilution cardiac output measurements.

METHODS

Eight anaesthetised swine had baseline measurements of heart rate, MAP, stroke volume, and stroke distance and were then exsanguinated at a rate of 1 ml/kg/min. Percentage changes from baseline of heart rate, MAP, stroke volume, and stroke distance were compared after 10, 20, and 30 ml/kg blood loss. The animal's blood was then reinfused at the rate of 2 ml/kg/min for 15 min, followed by normal saline 1 ml/kg/min. Percentage changes from baseline measurement of stroke volume and stroke distance over the whole experiment were evaluated by regression analysis.

RESULTS

Heart rate, MAP, and stroke distance changed +7.9%, -22.5%, and -18.1% respectively (from baseline values) after 10 ml/kg blood loss; +23.2%, -44.0%, and -47.4% after 20 ml/kg blood loss; and +55.7%, -62.0%, and -69.8% after 30 ml/kg blood loss. Regression analysis of percentage changes in stroke volume and stroke distance from their baseline values at experimental time zero is stroke volume = 1.014 x stroke distance -2.156, r = 0.92, n = 54, P < 0.0001.

CONCLUSIONS

(1) At maximal blood loss, stroke distance changes to a greater extent than heart rate and MAP. (2) Changes in stroke distance reflected changes in stroke volume but with less variability at lower values. Stroke distance may be a more useful measure of blood loss than heart rate and MAP.

Volumetric flow estimation in vivo and in vitro using pulsed-Doppler ultrasound

The measurement of volumetric blood flow in small vessels in vitro and in vivo poses a significant technological challenge. In this study, two pulsatile flow models were developed, one with a 3.2-mm lumen diameter and one with a 12.7-mm lumen diameter, to assess the accuracy of volumetric flow estimation of two pulsed-Doppler devices, a Crystal Biotech VF1 20-MHz system with either a cuff-mounted or a needle-mounted probe and an Advanced Technology Laboratories Ultramark 9 High Definition Imaging system with a 5-MHz linear array transducer. The VF1 volumetric flow error was measured in the 3.2-mm phantom over a variety of pulsatile and continuous waveforms. The accuracy of the VF1 was also tested in porcine femoral and renal arteries. VF1 volumetric flow error ranged from 4.8% to 54.3% in the in vivo studies. The ATL demonstrated similar volumetric flow errors in the porcine femoral artery (approximately 3.2 mm diameter), but these errors were reduced to < or = 17.4% in the 12.7-mm-diameter in vitro flow model.

The SPR3 gene encodes a sporulation-specific homologue of the yeast CDC3/10/11/12 family of bud neck microfilaments and is regulated by ABFI

The SPR3 gene is selectively activated only during the sporulation phase of the Saccharomyces cerevisiae (Sc) life cycle. The predicted amino acid (aa) sequence has homology to microfilament proteins that are involved in cytokinesis and other proteins of unknown function. These include the products of Sc cell division cycle (CDC) genes involved in bud formation (Cdc3p, Cdc10p, Cdc11p and Cdc12p), Candida albicans proteins that accumulate in the hyphal phase (CaCdc3p and CaCdc10p), mouse brain-specific (H5p) and lymphocyte (Diff6p) proteins, Drosophila melanogaster (Dm) protein Pnutp (which is localized to the cleavage furrow of dividing cells), a Diff6p homologue (DmDiff6p), and the Sc septin protein (Sep1hp), a homologue of the 10-nm filament proteins of Sc. One strongly conserved region contains a potential ATP-GTP-binding domain. Primer extension analysis revealed six major transcription start points (tsp) beginning at -142 relative to the ATG start codon. The sequence immediately upstream from the tsp contains consensus binding sites for the HAP2/3/4 and ABFI transcription factors, a T-rich sequence and two putative novel elements for mid to late sporulation, termed SPR3 and PAL. Electrophoretic mobility shift assay (EMSA) and footprint analyses demonstrated that the ABFI protein binds to a region containing the putative ABFI site in vitro, and site-directed mutagenesis showed that the ABFI motif is essential for expression of SPR3 at the appropriate stage in sporulating cells.

The use of ultrasound in the non-invasive detection of changes in the renal circulation in response to blood loss using an animal model

Using a continuous haemorrhage model, 8 anaesthetised swine were bled 1 ml/kg per min for 30 min. The resistance index (RI) of the main renal artery, interlobar and arcuate vessels all significantly increased. Cortical Doppler signals were lost in 4 animals at a mean arterial pressure of 26 mmHg. After reinfusion of blood and normal saline only the RI of the interlobar vessels was significantly different from baseline readings. Ultrasound demonstrated non-invasively changes in regional blood flow within the kidney in response to hypovolaemic shock.

Pneumatic anti-shock garment--does it have a future?

A total of 100 accident and emergency (A&E) departments in the UK responded to a questionnaire about their use of the pneumatic anti-shock garment (PASG). Less than one in 10 departments used PASG in their prehospital care system, less than one in five departments used PASG during in-patient care, and there was wide variation in PASG usage in those situations for which their use is recommended by the Advanced Trauma Life Support (ATLS) course.

The effect of audit and feedback on data recording in the accident and emergency department

Thirteen newly appointed senior house officers (SHOs) at two hospitals were assessed in the recording of two variables: Glasgow Coma Scale (GCS) and diagnostic coding at Hospital A, and GCS at Hospital B. At Hospitals A and B baseline recordings of these variables were established. Active feedback (in the form of data presentation and discussion) was given at 6 and 11 weeks and a final 4-week audit was performed on GCS recordings at 20 weeks. Analysis of GCS recordings of head injuries at Hospitals A and B showed an increase from baseline values of 162/401 (40%) to 336/420 (80%) after feedback 1, and after feedback 2 recordings increased to 379/429 (88%). This was maintained in the last 4-week audit which showed recordings of 220/244 (90%). Further analysis of Hospital A's data showed the SHOs recorded diagnostic coding in 1335/4406 (30%) of cases. After feedback 1, recordings increased to 2550/3327 (77%). After feedback 2 there was no change in recording 2712/3530 (77%). Active feedback improves data recording. The first feedback has a greater impact than the second. Two feedbacks produce a sustained effect in 6 months.

IME4, a gene that mediates MAT and nutritional control of meiosis in Saccharomyces cerevisiae

In the yeast Saccharomyces cerevisiae, sporulation occurs in response to nutritional and genetic signals. The process is initiated when nutrient availability limits mitotic growth, but only in MATa/MAT alpha diploid cells. Under these conditions, the cells express an activator of meiosis (IME1), which is required for the expression of early sporulation-specific genes. We describe a new gene, IME4, whose activity is essential for IME1 transcript accumulation and sporulation. The IME4 transcript was induced in starved MATa/MAT alpha diploids but not in other cell types. In addition, excess IME4 promoted sporulation in mat-insufficient cells. Thus, IME4 appears to activate IME1 in response to cell type and nutritional signals. We have also explored the interactions between IME4 and two genes that are known to regulate IME1 expression. Normally, cells that lack complete MAT information cannot sporulate; when such strains lack RME1 activity or contain the semidominant RES1-1 mutation, however, they can express IME1 and sporulate to low levels. Our results show that mat-insufficient strains containing rme1::LEU2 or RES1-1 bypass mutations still retain MAT control of IME4 expression. Even though IME4 levels remained low, the rme1::LEU2 and RES1-1 mutations allowed IME1 accumulation, implying that these mutations do not require IME4 to exert their effects. In accord with this interpretation, the RES1-1 mutation allowed IME1 accumulation in MATa/MAT alpha strains that contain ime4::LEU2 alleles. These strains still sporulated poorly, suggesting that IME4 plays a role in sporulation in addition to promoting IME1 transcript accumulation. IME4 is located between ADE5 and LYS5 on chromosome VII.

A study of the eye care provided by an accident and emergency department

The eye care provided by an Accident and Emergency (A&E) Department was prospectively studied over a 2-month period. Six out of a total of 506 patients were deemed to have been treated unsatisfactorily by the A&E Department. None of these patients suffered serious sequelae. Approximately one in three of those patients seen solely by A&E staff failed to have their visual acuity recorded.

An RME1-independent pathway for sporulation control in Saccharomyces cerevisiae acts through IME1 transcript accumulation

The RES1-1 mutation was isolated on the basis of its ability to allow MATa/MAT alpha diploid Saccharomyces cerevisiae cells to express a late sporulation-regulated gene, SPR3, in the presence of excess copies of RME1. RME1 is a repressor of meiosis that is normally expressed in cells that lack the a1/alpha 2 repressor encoded by MAT. The RES1-1 mutation also supports sporulation in mat-insufficient diploids. This phenotype does not result from a failure to express RME1 and is not due to activation of the silent copies of mating type information. RES1-1 activates sporulation by allowing IME1 accumulation in all cell types, irrespective of the presence of the MAT products. IME1 is still responsive to RME1 in RES1-1 cells, since double mutants (rme1 RES1-1) that are deficient at MAT can sporulate better than either single mutant. RES1-1 is not an allele of IME1.