Controversies in orthopaedic oncology

Chondrosarcoma is the second most common surgically treated primary bone sarcoma. Despite a large number of scientific papers in the literature, there is still significant controversy about diagnostics, treatment of the primary tumour, subtypes, and complications. Therefore, consensus on its day-to-day treatment decisions is needed. In January 2024, the Birmingham Orthopaedic Oncology Meeting (BOOM) attempted to gain global consensus from 300 delegates from over 50 countries. The meeting focused on these critical areas and aimed to generate consensus statements based on evidence amalgamation and expert opinion from diverse geographical regions. In parallel, periprosthetic joint infection (PJI) in oncological reconstructions poses unique challenges due to factors such as adjuvant treatments, large exposures, and the complexity of surgery. The meeting debated two-stage revisions, antibiotic prophylaxis, managing acute PJI in patients undergoing chemotherapy, and defining the best strategies for wound management and allograft reconstruction. The objectives of the meeting extended beyond resolving immediate controversies. It sought to foster global collaboration among specialists attending the meeting, and to encourage future research projects to address unsolved dilemmas. By highlighting areas of disagreement and promoting collaborative research endeavours, this initiative aims to enhance treatment standards and potentially improve outcomes for patients globally. This paper sets out some of the controversies and questions that were debated in the meeting.

Standardising clinical outcomes measures for adult clinical trials in Fabry disease: A global Delphi consensus

BACKGROUND

Recent years have witnessed a considerable increase in clinical trials of new investigational agents for Fabry disease (FD). Several trials investigating different agents are currently in progress; however, lack of standardisation results in challenges to interpretation and comparison. To facilitate the standardisation of investigational programs, we have developed a common framework for future clinical trials in FD.

METHODS AND FINDINGS

A broad consensus regarding clinical outcomes and ways to measure them was obtained via the Delphi methodology. 35 FD clinical experts from 4 continents, representing 3389 FD patients, participated in 3 rounds of Delphi procedure. The aim was to reach a consensus regarding clinical trial design, best treatment comparator, clinical outcomes, measurement of those clinical outcomes and inclusion and exclusion criteria. Consensus results of this initiative included: the selection of the adaptative clinical trial as the ideal study design and agalsidase beta as ideal comparator treatment due to its longstanding use in FD. Renal and cardiac outcomes, such as glomerular filtration rate, proteinuria and left ventricular mass index, were prioritised, whereas neurological outcomes including cerebrovascular and white matter lesions were dismissed as a primary or secondary outcome measure. Besides, there was a consensus regarding the importance of patient-related outcomes such as general quality of life, pain, and gastrointestinal symptoms. Also, unity about lysoGb3 and Gb3 tissue deposits as useful surrogate markers of the disease was obtained. The group recognised that cardiac T1 mapping still has potential but requires further development before its widespread introduction in clinical trials. Finally, patients with end-stage renal disease or renal transplant should be excluded unless a particular group for them is created inside the clinical trial.

CONCLUSION

This consensus will help to shape the future of clinical trials in FD. We note that the FDA has, coincidentally, recently published draft guidelines on clinical trials in FD and welcome this contribution.

Urinary Podocyte Loss Is Increased in Patients with Fabry Disease and Correlates with Clinical Severity of Fabry Nephropathy

Chronic kidney disease is a major complication of Fabry disease. Podocytes accumulate globotriaosylceramide inclusions more than other kidney cell types in Fabry patients. Podocyte injury occurs early in age, and is progressive. Since injured podocytes detach into the urine (podocyturia), we hypothesized that podocyturia would increase in Fabry patients and correlate with clinical severity of Fabry nephropathy. Urine specimens from 39 Fabry patients and 24 healthy subjects were evaluated for podocyturia. Most of the Fabry patients and many healthy subjects had podocyturia. The number of podocytes per gram of urine creatinine (UPodo/g Cr) was 3.6 fold greater in Fabry patients (3,741 ± 2796; p = 0.001) than healthy subjects (1,040 ± 972). Fabry patients with normoalbuminuria and normoproteinuria had over 2-fold greater UPodo/g Cr than healthy subjects (p = 0.048). UPodo/gCr was inversely related to eGFR in male patients (r = -0.69, p = 0.003). UPodo/gCr was directly related to urine protein creatinine ratio (r = 0.33; p = 0.04) in all Fabry patients. These studies confirm increased podocyturia in Fabry disease, even when proteinuria and albuminuria are absent. Podocyturia correlates with clinical severity of Fabry nephropathy, and potentially may be of prognostic value.

Late onset variants in Fabry disease: Results in high risk population screenings in Argentina

Background

Screening for Fabry disease (FD) in high risk populations yields a significant number of individuals with novel, ultra rare genetic variants in the GLA gene, largely without classic manifestations of FD. These variants often have significant residual α-galactosidase A activity. The establishment of the pathogenic character of previously unknown or rare variants is challenging but necessary to guide therapeutic decisions.

Objectives

To present 2 cases of non-classical presentations of FD with renal involvement as well as to discuss the importance of high risk population screenings for FD.

Results

Our patients with non-classical variants were diagnosed through FD screenings in dialysis units. However, organ damage was not limited to kidneys, since LVH, vertebrobasilar dolichoectasia and cornea verticillata were also present. Lyso-Gb3 concentrations in plasma were in the pathologic range, compatible with late onset FD. Structural studies and in silico analysis of p.(Cys174Gly) and p.(Arg363His), employing different tools, suggest that enzyme destabilization and possibly aggregation could play a role in organ damage.

Conclusions

Screening programs for FD in high risk populations are important as FD is a treatable multisystemic disease which is frequently overlooked in patients who present without classical manifestations.

Prevalence of apparent treatment-resistant hypertension among individuals with CKD

BACKGROUND AND OBJECTIVES

Apparent treatment-resistant hypertension is defined as systolic/diastolic BP ≥ 140/90 mmHg with concurrent use of three or more antihypertensive medication classes or use of four or more antihypertensive medication classes regardless of BP level.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The prevalence of apparent treatment-resistant hypertension among Reasons for Geographic and Racial Differences in Stroke study participants treated for hypertension (n=10,700) was determined by level of estimated GFR and albumin-to-creatinine ratio, and correlates of apparent treatment-resistant hypertension among those participants with CKD were evaluated. CKD was defined as an albumin-to-creatinine ratio ≥ 30 mg/g or estimated GFR<60 ml/min per 1.73 m(2).

RESULTS

The prevalence of apparent treatment-resistant hypertension was 15.8%, 24.9%, and 33.4% for those participants with estimated GFR ≥ 60, 45-59, and <45 ml/min per 1.73 m(2), respectively, and 12.1%, 20.8%, 27.7%, and 48.3% for albumin-to-creatinine ratio<10, 10-29, 30-299, and ≥ 300 mg/g, respectively. The multivariable-adjusted prevalence ratios (95% confidence intervals) for apparent treatment-resistant hypertension were 1.25 (1.11 to 1.41) and 1.20 (1.04 to 1.37) for estimated GFR levels of 45-59 and <45 ml/min per 1.73 m(2), respectively, versus ≥ 60 ml/min per 1.73 m(2) and 1.54 (1.39 to 1.71), 1.76 (1.57 to 1.97), and 2.44 (2.12 to 2.81) for albumin-to-creatinine ratio levels of 10-29, 30-299, and ≥ 300 mg/g, respectively, versus albumin-to-creatinine ratio<10 mg/g. After multivariable adjustment, men, black race, larger waist circumference, diabetes, history of myocardial infarction or stroke, statin use, and lower estimated GFR and higher albumin-to-creatinine ratio levels were associated with apparent treatment-resistant hypertension among individuals with CKD.

CONCLUSIONS

This study highlights the high prevalence of apparent treatment-resistant hypertension among individuals with CKD.

Geographic variation in CKD prevalence and ESRD incidence in the United States: results from the reasons for geographic and racial differences in stroke (REGARDS) study

BACKGROUND

It is not known whether geographic differences in the prevalence of chronic kidney disease exist and are associated with end-stage renal disease (ESRD) incidence rates across the United States.

STUDY DESIGN

Cross-sectional and ecologic.

SETTING & PARTICIPANTS

White (n = 16,410) and black (n = 11,109) participants from across the continental United States in the population-based Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study.

PREDICTOR

Geographic region, defined by the 18 networks of the US ESRD Network Program.

OUTCOMES & MEASUREMENTS

Albuminuria, defined as albumin-creatinine ratio ≥30 mg/g, and decreased estimated glomerular filtration rate (eGFR), defined as <60 mL/min/1.73 m(2), were measured in the REGARDS Study. ESRD incidence rates were obtained from the US Renal Data System.

RESULTS

For whites, the network-specific prevalence of albuminuria ranged from 8.4% (95% CI, 3.3%-13.5%) in Network 15 to 14.8% (95% CI, 8.0%-21.6%) in Network 3, and decreased eGFR ranged from 4.3% (95% CI, 2.0%-6.6%) in Network 4 to 16.7% (95% CI, 12.7%-20.7%) in Network 7. For blacks, the prevalence of albuminuria ranged from 12.1% (95% CI, 8.7%-15.5%) in Network 5 to 26.5% (95% CI, 16.7%-36.3%) in Network 4, and decreased eGFR ranged from 6.7% (95% CI, 5.0%-8.4%) in Network 17/18 to 13.4% (95% CI, 7.8%-19.1%) in Network 12. Spearman correlation coefficients for the prevalence of albuminuria and decreased eGFR with network-specific ESRD incidence rates were 0.49 and 0.24, respectively, for whites and 0.29 and 0.25, respectively, for blacks.

LIMITATIONS

There were few cases of albuminuria and decreased eGFR in some geographic regions.

CONCLUSIONS

In the United States, substantial geographic variations in the prevalence of albuminuria and decreased eGFR exist, but were correlated only modestly with ESRD incidence, suggesting the chronic kidney disease burden may not explain the geographic variation in ESRD incidence.

Older users, multimodal reminders and assisted living technology

The primary users of assisted living technology are older people who are likely to have one or more sensory impairments. Multimodal technology allows users to interact via non-impaired senses and provides alternative ways to interact if primary interaction methods fail. An empirical user study was carried out with older participants which evaluated the performance, disruptiveness and subjective workload of visual, audio, tactile and olfactory notifications then compared the results with earlier findings in younger participants. It was found that disruption and subjective workload were not affected by modality, although some modalities were more effective at delivering information accurately. It is concluded that although further studies need to be carried out in a real-world settings, the findings support the argument for multiple modalities in assisted living technology.

Albuminuria, kidney function, and the incidence of cognitive impairment among adults in the United States

BACKGROUND

Albuminuria and estimated glomerular filtration rate (eGFR) are each associated with increased risk of cognitive impairment, but their joint association is unknown.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

A US national sample of 19,399 adults without cognitive impairment at baseline participating in the REGARDS (Reasons for Geographic and Racial Disparities in Stroke) Study.

PREDICTORS

Albuminuria was assessed using urine albumin-creatinine ratio (UACR) and GFR was estimated using the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation.

OUTCOMES

Incident cognitive impairment was defined as score ≤4 on the 6-Item Screener at the last follow-up visit.

RESULTS

During a mean follow-up of 3.8 ± 1.5 years, UACRs of 30-299 and ≥300 mg/g were associated independently with 31% and 57% higher risk of cognitive impairment, respectively, relative to individuals with UACR <10 mg/g. This finding was strongest for those with high eGFRs and attenuated at lower levels (P = 0.04 for trend). Relative to eGFR ≥60 mL/min/1.73 m(2), eGFR <60 mL/min/1.73 m(2) was not associated independently with cognitive impairment. However, after stratifying by UACR, eGFR <60 mL/min/1.73 m(2) was associated with a 30% higher risk of cognitive impairment in participants with UACR <10 mg/g, but not higher UACRs (P = 0.04 for trend).

LIMITATIONS

Single measures of albuminuria and eGFR, screening test of cognition.

CONCLUSIONS

When eGFR was preserved, albuminuria was associated independently with incident cognitive impairment. When albuminuria was <10 mg/g, low eGFR was associated independently with cognitive impairment. Albuminuria and low eGFR are complementary, but not additive, risk factors for incident cognitive impairment.

Detection of chronic kidney disease with creatinine, cystatin C, and urine albumin-to-creatinine ratio and association with progression to end-stage renal disease and mortality

CONTEXT

A triple-marker approach for chronic kidney disease (CKD) evaluation has not been well studied.

OBJECTIVE

To evaluate whether combining creatinine, cystatin C, and urine albumin-to-creatinine ratio (ACR) would improve identification of risks associated with CKD compared with creatinine alone.

DESIGN, SETTING, AND PARTICIPANTS

Prospective cohort study involving 26,643 US adults enrolled in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study from January 2003 to June 2010. Participants were categorized into 8 groups defined by estimated glomerular filtration rate (GFR) determined by creatinine and by cystatin C of either <60 or ≥60 mL/min/1.73 m(2) and ACR of either <30 or ≥30 mg/g.

MAIN OUTCOME MEASURES

All-cause mortality and incident end-stage renal disease with median follow-up of 4.6 years.

RESULTS

Participants had a mean age of 65 years, 40% were black, and 54% were women. Of 26,643 participants, 1940 died and 177 developed end-stage renal disease. Among participants without CKD defined by creatinine, 24% did not have CKD by either ACR or cystatin C. Compared with those with CKD defined by creatinine alone, the hazard ratio for death in multivariable-adjusted models was 3.3 (95% confidence interval [CI], 2.0-5.6) for participants with CKD defined by creatinine and ACR; 3.2 (95% CI, 2.2-4.7) for those with CKD defined by creatinine and cystatin C, and 5.6 (95% CI, 3.9-8.2) for those with CKD defined by all biomarkers. Among participants without CKD defined by creatinine, 3863 (16%) had CKD detected by ACR or cystatin C. Compared with participants who did not have CKD by any measure, the HRs for mortality were 1.7 (95% CI, 1.4-1.9) for participants with CKD defined by ACR alone, 2.2 (95% CI, 1.9-2.7) for participants with CKD defined by cystatin C alone, and 3.0 (95% CI, 2.4-3.7) for participants with CKD defined by both measures. Risk of incident end-stage renal disease was higher among those with CKD defined by all markers (34.1 per 1000 person-years; 95% CI, 28.7-40.5 vs 0.33 per 1000 person-years; 95% CI, 0.05-2.3) for those with CKD defined by creatinine alone. The second highest end-stage renal disease rate was among persons missed by the creatinine measure but detected by both ACR and cystatin C (rate per 1000 person-years, 6.4; 95% CI, 3.6-11.3). Net reclassification improvement for death was 13.3% (P < .001) and for end-stage renal disease was 6.4% (P < .001) after adding estimated GFR cystatin C in fully adjusted models with estimated GFR creatinine and ACR.

CONCLUSION

Adding cystatin C to the combination of creatinine and ACR measures improved the predictive accuracy for all-cause mortality and end-stage renal disease.

QT prolongation is an independent predictor of mortality in end-stage renal disease

BACKGROUND

Coronary artery disease (CAD) is the predominant cause of sudden cardiac death in the general population, and sudden cardiac death is the leading cause of mortality in end-stage renal disease (ESRD).

HYPOTHESIS

QT-interval prolongation is an independent prognosticator in ESRD.

METHODS

We reviewed clinical, electrocardiographic, stress test, and coronary angiography data on ESRD patients evaluated for transplantation at our institution between 2000 and 2004 who underwent coronary angiography. The QT interval was corrected for heart rate and QRS duration (QTc). All-cause mortality data were prospectively collected and verified against the Social Security Death Index database.

RESULTS

During 40 +/- 28 months of follow-up, 132 of the 280 (47%) patients died prior to renal transplantation. Patients with a prolonged QTc (39%) had 1-, 3-, and 5-year death-rates of 12%, 36%, and 47%, respectively, vs 8%, 24%, and 36% for those with normal QTc (log-rank P = 0.03). In a multivariate Cox regression model that adjusted for age, gender, diabetes mellitus, myocardial infarction, presence and severity of CAD on angiography, left ventricular (LV) hypertrophy, LV ejection fraction (EF), and multiple other variables, QTc remained to be an independent predictor of survival (hazard ratio [HR]: 1.008, 95% confidence interval [CI]: 1.001-1.014, P = 0.016). Female gender, decreasing LVEF, and decreasing severity of CAD on angiography were independent predictors of prolonged QTc.

CONCLUSIONS

QTc prolongation is an independent predictor of mortality in ESRD patients being evaluated for renal transplantation. The prognostic information gained from the QTc is additive to that provided by the LVEF and the severity of CAD.

Evaluation and initial management of acute kidney injury

The evaluation and initial management of patients with acute kidney injury (AKI) should include: (1) an assessment of the contributing causes of the kidney injury, (2) an assessment of the clinical course including comorbidities, (3) a careful assessment of volume status, and (4) the institution of appropriate therapeutic measures designed to reverse or prevent worsening of functional or structural kidney abnormalities. The initial assessment of patients with AKI classically includes the differentiation between prerenal, renal, and postrenal causes. The differentiation between so-called "prerenal" and "renal" causes is more difficult, especially because renal hypoperfusion may coexist with any stage of AKI. Using a modified Delphi approach, the multidisciplinary international working group, generated a set of testable research questions. Key questions included the following: Is there a difference in prognosis between volume-responsive and volume-unresponsive AKI? Are there biomarkers whose patterns (dynamic changes) predict the severity and recovery of AKI (maximal stage of AKI, need for RRT, renal recovery, mortality) and guide therapy? What is the best biomarker to assess prospectively whether AKI is volume responsive? What is the best biomarker to assess the optimal volume status in AKI patients? In evaluating the current literature and ongoing studies, it was thought that the answers to the questions posed herein would improve the understanding of AKI, and ultimately patient outcomes.

Predictors of survival in patients with end-stage renal disease evaluated for kidney transplantation

Cardiovascular disease is the major cause of mortality in patients with end-stage renal disease (ESRD). This study examined the all-cause mortality in 3,698 patients with ESRD evaluated for kidney transplantation at our institution from 2001 to 2004. Mean age for the cohort was 48+/-12 years, and 42% were women. Stress myocardial perfusion imaging was done in 2,207 patients (60%) and coronary angiography in 260 patients (7%). There were 622 deaths (17%) during a mean follow-up period of 30+/-15 months. The presence and severity of coronary disease on angiography was not predictive of survival. Coronary revascularization did not impact survival (p=0.6) except in patients with 3-vessel disease (p=0.05). The best predictor of death was left ventricular ejection fraction, measured by gated myocardial perfusion imaging, with 2.7% mortality increase for each 1% ejection fraction decrease. In conclusion, left ventricular ejection fraction is a strong predictor of survival in patients with ESRD awaiting renal transplantation. Strategies to improve cardiac function or earlier renal transplantation deserve further studies.

Epidemiology of candidemia in Brazil: a nationwide sentinel surveillance of candidemia in eleven medical centers

Candidemia studies have documented geographic differences in rates and epidemiology, underscoring the need for surveillance to monitor trends. We conducted prospective candidemia surveillance in Brazil to assess the incidence, species distribution, frequency of antifungal resistance, and risk factors for fluconazole-resistant Candida species. Prospective laboratory-based surveillance was conducted from March 2003 to December 2004 in 11 medical centers located in 9 major Brazilian cities. A case of candidemia was defined as the isolation of Candida spp. from a blood culture. Incidence rates were calculated per 1,000 admissions and 1,000 patient-days. Antifungal susceptibility tests were performed by using the broth microdilution assay, according to the Clinical and Laboratory Standards Institute guidelines. We detected 712 cases, for an overall incidence of 2.49 cases per 1,000 admissions and 0.37 cases per 1,000 patient-days. The 30-day crude mortality was 54%. C. albicans was the most common species (40.9%), followed by C. tropicalis (20.9%) and C. parapsilosis (20.5%). Overall, decreased susceptibility to fluconazole occurred in 33 (5%) of incident isolates, 6 (1%) of which were resistant. There was a linear correlation between fluconazole and voriconazole MICs (r = 0.54 and P < 0.001 [Spearman's rho]). This is the largest multicenter candidemia study conducted in Latin America and shows the substantial morbidity and mortality of candidemia in Brazil. Antifungal resistance was rare, but correlation between fluconazole and voriconazole MICs suggests cross-resistance may occur.

Mold prevention strategies and possible health effects in the aftermath of hurricanes and major floods

Extensive water damage after major hurricanes and floods increases the likelihood of mold contamination in buildings. This report provides information on how to limit exposure to mold and how to identify and prevent mold-related health effects. Where uncertainties in scientific knowledge exist, practical applications designed to be protective of a person's health are presented. Evidence is included about assessing exposure, clean-up and prevention, personal protective equipment, health effects, and public health strategies and recommendations. The recommendations assume that, in the aftermath of major hurricanes or floods, buildings wet for <48 hours will generally support visible and extensive mold growth and should be remediated, and excessive exposure to mold-contaminated materials can cause adverse health effects in susceptible persons regardless of the type of mold or the extent of contamination. For the majority of persons, undisturbed mold is not a substantial health hazard. Mold is a greater hazard for persons with conditions such as impaired host defenses or mold allergies. To prevent exposure that could result in adverse health effects from disturbed mold, persons should 1) avoid areas where mold contamination is obvious; 2) use environmental controls; 3) use personal protective equipment; and 4) keep hands, skin, and clothing clean and free from mold-contaminated dust. Clinical evaluation of suspected mold-related illness should follow conventional clinical guidelines. In addition, in the aftermath of extensive flooding, health-care providers should be watchful for unusual mold-related diseases. The development of a public health surveillance strategy among persons repopulating areas after extensive flooding is recommended to assess potential health effects and the effectiveness of prevention efforts. Such a surveillance program will help CDC and state and local public health officials refine the guidelines for exposure avoidance, personal protection, and clean-up and assist health departments to identify unrecognized hazards.

Management and outcome after local recurrence of osteosarcoma

We report on the management and outcome of 96 patients who developed local recurrence (LR) after having definitive primary treatment with chemotherapy and surgery for non-metastatic osteosarcoma. LR developed at a median of 11 months from initial surgical treatment. 18% of patients had metastases prior to the diagnosis of LR and 23% were found to have metastases synchronously. The prognosis for this group with metastases was 14% survival at 2 years. In the 57 patients without metastases at the time of development of LR, survival was 51% at 2 years and 41% at 5 years. Treatment was by excision of the LR and radiotherapy or by amputation. The only significant prognostic factors identified were the presence of metastases at the time of development of LR (P < 0.0001) and small size of the LR. The role of adjuvant chemotherapy was unclear. Whilst every attempt should be made to avoid LR, patients who develop LR are curable, particularly if they do not have metastases at the time of diagnosis of the LR.

The early management of severe tibial pilon fractures using a temporary ring fixator

BACKGROUND

The management of pilon fractures of the distal tibia is fraught with complications. Poor initial management leads to a poorer outcome. Protection of the soft tissue envelope is paramount and to achieve this objective early fracture reduction, restoration of leg length and elevation are important principles in the management of severe injuries. Reduction and restoration of length can be achieved through ligamentotaxis by various methods but the most commonly employed are calcaneal traction or bridging external fixation.

OBJECTIVE

We describe our method for the early management of these injuries using a simple semicircular bridging frame.

Issues related to iron replacement in chronic kidney disease

Recent epidemiologic studies show that iron deficiency occurs in the vast majority of patients with chronic kidney disease (CKD). In patients with CKD, increased iron losses and, to a lesser extent, poor oral absorption, can lead to iron-deficiency anemia. Correction of iron-deficiency anemia is preferable by the oral route, however, data on oral iron use are limited in this population. In CKD patients, parenteral iron administered with recombinant human erythropoietin (rHuEpo), is the best potential option for the correction of anemia. Nondextran iron preparations are preferable because of a reduced incidence of serious adverse events. Parenteral iron in CKD patients may not be entirely innocuous and, although commonly used, have not received Food and Drug Administration approval for use in this patient population. Exposure to intravenous (IV) iron may lead to oxidative stress, renal injury, infection, cardiovascular disease, and osteomalacia. Studies are needed to confirm the existence and magnitude of these complications. The current data suggest that the overall risk-benefit ratio favors use of IV iron when compared with untreated or partially treated iron-deficiency anemia.

Epidemiology: surveillance of fungal infections

Surveillance for fungal diseases is essential to improve our understanding of their epidemiology and to enable research and prevention efforts to be prioritized. In order to conduct better surveillance for fungal diseases, it is important to develop more accurate and timely diagnostic tests, to follow rigorous epidemiological methods and to have adequate support from public health agencies and the pharmaceutical industry. Investigations of nosocomial and community outbreaks of fungal infection have also resulted in a better understanding of the sources and routes of transmission of these diseases, and of the risk factors for infection. This has led to more effective prevention and control strategies. In addition, outbreak investigations have offered excellent opportunities to develop new molecular sub-typing methods, and to evaluate and validate older ones. For example, results obtained from a global epidemiological study of the genomic structure of Cryptococcus neoformans have led to a better understanding of the epidemiology of cryptococcosis. Similarly, a study of variations in the genotype of Trichophyton rubrum has found that patients may become infected with multiple strains, which has important implications for study design when looking at the epidemiology of dermatophyte infections.

Involvement of renal apical Na transport systems in the control of blood pressure

Human genetic studies and gene targeting techniques in mice suggest that the genes encoding renal apical Na transport proteins play an essential role in the control of extracellular fluid volume and blood pressure. Particularly, very significant advancements in understanding the role of these genes in Mendelian forms of hypertension or hypotension have been achieved in recent years. However, much progress still needs to be made in understanding the more common forms of human essential hypertension. In addition to the mouse models that should be very useful for investigating the mechanisms by which a mutation provokes the hypertensive phenotype, improved clinical phenotyping of patients is needed as well as the use of DNA chip techniques to unravel global gene interactions. Indeed, it is likely that most chronic blood pressure disturbances in a given environment result from a specific combination of polymorphisms or mutations rather than from unique genetic variants. Of equal importance will be definition of the various factors that regulate the expression and activity of the Na transport systems. These regulatory pathways and the responses to environmental factors such as dietary salt, stress, etc, may play a central role in determining the appearance, severity, and complications of essential hypertension.

Serum itraconazole concentrations and clinical responses in Candida-associated denture stomatitis patients treated with itraconazole solution and itraconazole capsules

The aim of this study was to compare the concentrations of itraconazole in serum and saliva after treatment with itraconazole cyclodextrin solution or itraconazole capsules in Candida-associated denture stomatitis patients without evidence of immunodeficiency. Forty patients were randomly assigned to receive either itraconazole cyclodextrin solution or itraconazole capsules, both at a dosage of 100 mg bd for 15 days. On completion of treatment palatal erythema was assessed and an oral rinse and imprint cultures were collected. Serum and saliva samples were collected at the same time and itraconazole concentrations measured using reverse-phase high-performance liquid chromatography. Itraconazole susceptibilities of Candida albicans and Candida glabrata strains isolated at baseline were measured by a broth microdilution method. Serum itraconazole concentrations achieved did not differ significantly between the two preparations (P = 0.39) although a significantly higher number of patients in the itraconazole cyclodextrin group (P < 0.001) had detectable levels of itraconazole in their saliva compared with the capsule group. Mycologically cured patients had slightly, though not significantly (P = 0.28), higher serum itraconazole concentrations than those from whom yeasts were not eradicated. It was concluded that both formulations of itraconazole were equally effective in treatment of denture stomatitis. Among immunocompetent patients, the absorption of the liquid preparation is no greater than that of the capsules. Therapeutic success in this group was achieved with lower serum itraconazole concentrations than have been reported for immunocompromised groups.

Diagnosis of invasive aspergillosis in bone marrow transplant recipients by polymerase chain reaction

A nested polymerase chain reaction (PCR) test targeting Aspergillus spp. large ribosomal subunit genes was evaluated retrospectively on 175 serum samples from 37 bone marrow transplant recipients, 70% of whom received grafts from unrelated donors. Six patients had proven infection, seven had probable infection, and three had possible infection, using the revised EORTC case definitions. These 16 patients were all PCR positive (57 out of 93 samples tested). Two additional patients who did not fulfil current diagnostic criteria, but in whom invasive aspergillosis (IA) was thought clinically probable, were also PCR positive (five out of nine samples). Invasive aspergillosis was unlikely in the remaining 19 patients, four of whom were PCR positive on a single occasion (four out of 70 samples). Three samples were inhibitory to PCR. Sensitivity of PCR in diagnosing patients with IA was 100%, specificity was 79% and positive predictive value was 80%, using the criterion of a single positive result. If two positive results were required, these values were 81%, 100% and 100% respectively. The median duration of infection documented by PCR was 36 days (range 3-248 days) in 17 out of 18 patients (94%) who did not survive. Positive PCR results predated the institution of antifungal therapy in two-thirds of patients. Four patients became PCR positive during pretransplant conditioning therapy.

Multicenter clinical trial of recombinant human insulin-like growth factor I in patients with acute renal failure

BACKGROUND

Patients with acute renal failure (ARF) have high morbidity and mortality rates, particularly if they have serious comorbid conditions. Several studies indicate that in rats with ARF caused by ischemia or certain nephrotoxins, insulin-like growth factor-I (IGF-I) enhances the recovery of renal function and suppresses protein catabolism.

METHODS

Our objective was to determine whether injections of recombinant human IGF-I (rhIGF-I) would enhance the recovery of renal function and is safe in patients with ARF. The study was designed as a randomized, double-blind, placebo-controlled trial in intensive care units in 20 teaching hospitals. Seventy-two patients with ARF were randomized to receive rhIGF-I (35 patients) or placebo (37 patients). The most common causes of ARF in the rhIGF-I and placebo groups were, respectively, sepsis (37 and 35% of patients) and hypotension or hemodynamic shock (42 and 27% of patients). At baseline, the mean (+/- SD) APACHE II scores in the rhIGF-I and placebo-treated groups were 24 +/- 5 and 25 +/- 8, respectively. In the rhIGF-I and placebo groups, the mean (median) urine volume and urinary iothalamate clearances (glomerular filtration rate) were 1116 +/- 1037 (887) and 1402 +/- 1183 (1430) ml/24 hr and 6.4 +/- 5.9 (4.3) and 8.7 +/- 7.2 (4.4) ml/min and did not differ between the two groups. Patients were injected subcutaneously every 12 hours with rhIGF-I, 100 microgram/kg desirable body weight, or placebo for up to 14 days. Injections were started within six days of the onset of ARF. The primary end-point was a change in glomerular filtration rate from baseline. Other end points included changes from baseline in urine volume, creatinine clearance and serum urea, creatinine, albumin and transferrin, frequency of hemodialysis or ultrafiltration, and mortality rate.

RESULTS

During the treatment period, which averaged 10.7 +/- 4.1 and 10.6 +/- 4.5 days in the rhIGF-I and placebo groups, there were no differences in the changes from baseline values of the glomerular filtration rate, creatinine clearance, daily urine volume, or serum urea nitrogen, creatinine, albumin or transferrin. In patients who did not receive renal replacement therapy, there was also no significant difference in serum creatinine and urea between the two groups. Twenty patients in the rhIGF-I group and 17 placebo-treated patients underwent dialysis or ultrafiltration. Twelve rhIGF-I-treated patients and 12 placebo-treated patients died during the 28 days after the onset of treatment.

CONCLUSIONS

rhIGF-I does not accelerate the recovery of renal function in ARF patients with substantial comorbidity.

Structural requirements for PAK activation by Rac GTPases

The Rho family GTPases, Rac1 and Rac2, regulate a variety of cellular functions including cytoskeletal reorganization, the generation of reactive oxygen species, G1 cell cycle progression and, in concert with Ras, oncogenic transformation. Among the many putative protein targets identified for Rac (and/or Cdc42), the Ser/Thr kinase p21-activated kinase (PAK) is a prime candidate for mediating some of Rac's cellular effects. This report shows that Rac1 binds to and stimulates the kinase activity of PAK1 approximately 2- and 4-5-fold, respectively, better than Rac2. Mutational analysis was employed to determine the structural elements on Rac and PAK that are important for optimal binding and activation. The most notable difference between the highly homologous Rac isomers is the composition of their C-terminal polybasic domains. Mutation of these six basic residues in Rac1 to neutral amino acids dramatically decreased the ability of Rac1 to bind PAK1 and almost completely abolished its ability to stimulate PAK activity. Moreover, replacing the highly charged polybasic domain of Rac1 with the less charged domain of Rac2 (and vice versa) completely reversed the PAK binding/activation properties of the two Rac isomers. Thus, polybasic domain differences account for the disparate abilities of Rac1 and Rac2 to activate PAK. PAK proteins also contain a basic region, consisting of three contiguous lysine residues (Lys66-Lys67-Lys68), which lies outside of the previously identified Cdc42/Rac-binding domain. Mutation of these Lys residues to neutral residues decreased PAK binding to activated Rac1 and Rac2 (but not Cdc42) and greatly reduced PAK1 activation by Rac1, Rac2, and Cdc42 proteins in vivo. In contrast, mutation of lysines 66-68 to basic Arg residues did not decrease (and in some cases enhanced) the ability of Rac1, Rac2, and Cdc42 to bind and activate PAK1. Our studies suggest that the polybasic domain of Rac is a novel effector domain that may allow the two Rac isomers to activate different effector proteins. In addition, our results indicate that a basic region in PAK is required for PAK activation and that binding of Rac/Cdc42 to PAK is not sufficient for kinase activation.

Candida glabrata epididymo-orchitis: an unusual infection rapidly cured with surgical and antifungal treatment

We report a case of epididymo-orchitis and secondary fungaemia caused by Candida (previously Torulopsis) glabrata in an 83-year-old male patient who had diabetes mellitus, urinary outflow obstruction and previous bladder malignancy. We believe this to be a previously unreported site of infection with C. glabrata and we describe its rapid and successful treatment with combination anti-fungal therapy.

GLUT-4 NH2 terminus contains a phenylalanine-based targeting motif that regulates intracellular sequestration

Expression of chimeras, composed of portions of two different glucose transporter isoforms (GLUT-1 and GLUT-4), in CHO cells had indicated that the cytoplasmic NH2 terminus of GLUT-4 contains important targeting information that mediates intracellular sequestration of this isoform (Piper, R. C., C. Tai, J. W. Slot, C. S. Hahn, C. M. Rice, H. Huang, D. E. James. 1992. J. Cell Biol. 117:729-743). In the present studies, the amino acid constituents of the GLUT-4 NH2-terminal targeting domain have been identified. GLUT-4 constructs containing NH2-terminal deletions or alanine substitutions within the NH2 terminus were expressed in CHO cells using a Sindbis virus expression system. Deletion of eight amino acids from the GLUT-4 NH2 terminus or substituting alanine for phenylalanine at position 5 in GLUT-4 resulted in a marked accumulation of the transporter at the plasma membrane. Mutations at other amino acids surrounding Phe5 also caused increased cell surface expression of GLUT-4 but not to the same extent as the Phe5 mutation. GLUT-4 was also localized to clathrin lattices and this colocalization was abolished when either the first 13 amino acids were deleted or when Phe5 was changed to alanine. To ascertain whether the targeting information within the GLUT-4 NH2-terminal targeting domain could function independently of the glucose transporter structure this domain was inserted into the cytoplasmic tail of the H1 subunit of the asialoglycoprotein receptor. H1 with the GLUT-4 NH2 terminus was predominantly localized to an intracellular compartment similar to GLUT-4 and was sequestered more from the cell surface than was the wild-type H1 protein. It is concluded that the NH2 terminus of GLUT-4 contains a phenylalanine-based targeting motif that mediates intracellular sequestration at least in part by facilitating interaction of the transporter with endocytic machinery located at the cell surface.