Imaging glioma biology: spatial comparison of amino acid PET, amide proton transfer, and perfusion-weighted MRI in newly diagnosed gliomas

PURPOSE

Imaging glioma biology holds great promise to unravel the complex nature of these tumors. Besides well-established imaging techniques such O-(2-[18F]fluoroethyl)-L-tyrosine (FET)-PET and dynamic susceptibility contrast (DSC) perfusion imaging, amide proton transfer-weighted (APTw) imaging has emerged as a promising novel MR technique. In this study, we aimed to better understand the relation between these imaging biomarkers and how well they capture cellularity and vascularity in newly diagnosed gliomas.

METHODS

Preoperative MRI and FET-PET data of 46 patients (31 glioblastoma and 15 lower-grade glioma) were segmented into contrast-enhancing and FLAIR-hyperintense areas. Using established cutoffs, we calculated hot-spot volumes (HSV) and their spatial overlap. We further investigated APTw and CBV values in FET-HSV. In a subset of 10 glioblastoma patients, we compared cellularity and vascularization in 34 stereotactically targeted biopsies with imaging.

RESULTS

In glioblastomas, the largest HSV was found for APTw, followed by PET and CBV (p < 0.05). In lower-grade gliomas, APTw-HSV was clearly lower than in glioblastomas. The spatial overlap of HSV was highest between APTw and FET in both tumor entities and regions. APTw correlated significantly with cellularity, similar to FET, while the association with vascularity was more pronounced in CBV and FET.

CONCLUSIONS

We found a relevant spatial overlap in glioblastomas between hotspots of APTw and FET both in contrast-enhancing and FLAIR-hyperintense tumor. As suggested by earlier studies, APTw was lower in lower-grade gliomas compared with glioblastomas. APTw meaningfully contributes to biological imaging of gliomas.

Relation of Myocardial Blood Flow and Initial Cardiac Uptake of 15-(p-123I-Phenyl)-Pentadecanoic Acid in the Canine Heart

In 8 pentobarbital-anaesthetized mongrel dogs the correlation between regional myocardial blood flow (RMBF) and regional cardiac uptake of 15-(p-123I-phenyl)-pentadecanoic acid (IPPA) was determined. Three animals were studied under control conditions, in three dogs an acute ischemia was produced by LAD ligation, and two dogs were paced at 195 beats/min. RMBF values were 20–50 ml/min-100 g in acutely ischemic myocardium. 90–120 ml/ min·100 g under normal conditions and 200–250 ml/min·100 g during pacing-induced stimulation. Total cardiac uptake of IPPA was 4.5–6% of the injected dose. In normal and acutely ischemic myocardium a good correlation between RMBF and IPPA uptake was obtained. Under stimulated conditions only a moderate increase of IPPA accumulation was found. At RMBF values above 150–170 ml/ min·100 g an upper limit of IPPA uptake was observed and can be explained by limited diffusion or an increased utilization of alternative substrates.

Socio-economic factors influencing the development of end-stage renal disease in people with Type 1 diabetes - a longitudinal population study

AIMS

The development of end-stage renal disease (ESRD) in Type 1 diabetes is multifactorial. Familial socio-economic factors may influence adherence to and understanding of diabetes treatment, and also general health behaviour. We investigate how parental and personal education level and exposure to low economic status, indicated by the need for income support, influence the development of ERSD caused by Type 1 diabetes.

METHODS

Participants were retrieved from the nationwide Swedish Childhood Diabetes Registry, which was linked to the Swedish Renal Registry, to find people with ESRD caused by Type 1 diabetes, and to Statistic Sweden to retrieve longitudinal socio-economic data on participants and their parents. Data were analysed using Cox regression modelling.

RESULTS

Of 9287 people with diabetes of duration longer than 14 years, 154 had developed ESRD due to diabetes. Median diabetes duration (range) for all participants was 24.2 years (14.0-36.7 years). Low maternal education (≤ 12 years) more than doubled the risk of developing ESRD, hazard ration (HR) = 2.9 [95% confidence interval (95% CI): 1.7-4.8]. For people with a low personal level of education HR was 5.7 (3.4-9.5). In an adjusted model, the person's own education level had the highest impact on the risk of ESRD. If at least one of the parents had ever received income support the HR was 2.6 (1.9-3.6).

CONCLUSIONS

Socio-economic factors, both for the parents and the person with diabetes, have a strong influence on the development of ESRD in Type 1 diabetes. It is important for caregivers to give enough support to more vulnerable people and their families.

A circuit analysis of an in situ tunable radio-frequency quantum point contact

A detailed analysis of the tunability of a radio-frequency quantum point contact setup using a C - LCR circuit is presented. We calculate how the series capacitance influences resonance frequency and charge-detector resistance for which matching is achieved as well as the voltage and power delivered to the load. Furthermore, we compute the noise contributions in the system and compare our findings with measurements taken with an etched quantum point contact. While our considerations mostly focus on our specific choice of matching circuit, the discussion of the influence of source-to-load power transfer on the signal-to-noise ratio is valid generally.

Relation between renal function, presentation, use of therapies and in-hospital complications in acute coronary syndrome: data from the SWEDEHEART register

OBJECTIVE

To examine clinical characteristics, presenting symptoms, use of therapy and in-hospital complications in relation to renal function in patients with myocardial infarction (MI).

DESIGN

Observational study.

SETTING

Nationwide coronary care unit registry between 2003-2006 in Sweden.

SUBJECTS

Consecutive MI patients with available creatinine (n = 57,477).

RESULTS

Glomerular filtration rate was estimated with the Modification of Diet in Renal Disease Study formula. With declining renal function patients were older, had more co-morbidities and more often used cardio-protective medication on admission. Compared to patients with normal renal function, fewer with renal failure presented with chest pain (90% vs. 67%, P < 0.001), Killip I (89% vs. 58%, P < 0.001) and ST-elevation myocardial infarction (STEMI) (41% vs. 22%, P < 0.001). In a logistic regression model lower renal function was independently associated with a less frequent use of anticoagulant and revascularization in non-ST-elevation MI. The likelihood of receiving reperfusion therapy for STEMI was similar in patients with normal-to-moderate renal dysfunction, but decreased in severe renal dysfunction or renal failure. Reperfusion therapy shifted from primary percutaneous coronary intervention in 71% of patients with normal renal function to fibrinolysis in 58% of those with renal failure. Renal function was associated with a higher rate of complications and an exponential increase in in-hospital mortality from 2.5% to 24.2% across the renal function groups.

CONCLUSION

Renal insufficiency influences the presentation and reduces the likelihood of receiving treatment according to current guidelines. Short-term prognosis remains poor.

Renal replacement therapy in Sweden

OBJECTIVE

The Swedish Registry for Active Treatment of Uraemia (SRAU) was founded in 1991 with the objective of documenting demographic data on patients treated for end-stage renal disease (ESRD). The aim of this study was to describe the prevalence, incidence, comorbidity risk factors and survival of patients with ESRD who underwent dialysis treatment and/ or kidney transplantation in Sweden between 1991 and 2002.

MATERIAL AND METHODS

All dialysis and transplant units (n = 65) presently report to the SRAU and almost all patients are reported and followed until death.

RESULTS

The prevalence of patients on dialysis and transplantation, being approximately 750 per million population (PMP), has increased by 75% in 12 years. The recent annual rise is approximately 3% (200 patients). The incidence has been stable since 1997 at approximately 125 patients PMP. In 2002, there were 1113 new patients, the majority of whom were aged > or =65 years. Their original kidney disease was most often diabetic nephropathy (23.7%), with nephrosclerosis (19.0%) being the second most common disease. The total number of renal transplantations performed has decreased to some extent. The overall 5-year patient survival rate was 23.1% in patients on dialysis and 85.5% after kidney transplantation. The major cause of death was cardiovascular disease (48%) and an increasing frequency of malignancy after transplantation (26%) was noted.

CONCLUSION

The prevalence of ESRD has nearly doubled since 1990 and the number of new patients being referred for dialysis has increased. These patients are becoming older, with a large proportion having non-renal complicating diseases. Survival after transplantation was excellent. The shortage of cadaveric donors in Sweden in recent years and increasing mortality from malignant disease after transplantation are issues of great concern.

Prevalence and incidence of Type 2 diabetes and its complications 1996-2003--estimates from a Swedish population-based study

AIMS

To determine the prevalence and incidence of Type 2 diabetes and its complications in Uppsala county, Sweden between 1996 and 2003.

METHODS

Retrospective population-based study of patients with Type 2 diabetes identified in computerized medical records at 26 county primary care centres. Prevalence and incidence of Type 2 diabetes were estimated in the population aged 30-39, 40-49, 50-59, 60-69, 70-79 and > or = 80 years. Mortality, prevalence and incidence of complications in patients with Type 2 diabetes were determined through linkage to national inpatient, uraemia and cause-of-death registers.

RESULTS

Crude prevalence of Type 2 diabetes increased from 2.2 to 3.5% between 1996 and 2003. In the population aged > or = 30 years, the age- and sex-adjusted period increase was 53%[odds ratio (OR) 1.53, 95% confidence interval (CI) 1.47-1.58]. Crude population incidence was approximately stable after 1997 (3.7 cases/1000 residents in 1997 compared with 3.8/1000 in 2003). Age- and sex-adjusted mortality rates in Type 2 diabetic patients decreased by 4% per year (OR 0.96, 95% CI 0.94-0.97). Prevalence rates of cardiovascular disease in Type 2 diabetic patients were essentially stable, affecting 13.8% of females and 18.0% of males in 2003. No trend was detected for prevalence of renal failure or incidence of acute myocardial infarction, stroke and amputation.

CONCLUSIONS

Prevalence of Type 2 diabetes increased in Uppsala county between 1996 and 2003 as a consequence of approximately stable incidence since 1997 and declining mortality. Rates of diabetes-related complications, notably cardiovascular disease, continued to impose a substantial burden.

Effect of general population mortality on the north-south mortality gradient in patients on replacement therapy in Europe

In Europe there is considerable variation in mortality on renal replacement therapy (RRT). The causes of this variation are still poorly understood. We hypothesized that differences in mortality in the general population contribute to differences in mortality on RRT. To evaluate this relationship, we studied general population statistics obtained from Eurostat and the individual data of 67,692 patients on RRT from 15 national and regional renal registries. These 15 registries were divided into two geographical regions: North and South Europe. Cox regression was used to assess the relative risk of death (RR) for each region with adjustment for age, gender, diabetes, and additionally general population mortality. In patients on RRT the age, gender and diabetes adjusted RR of death was 0.65 (95% CI (0.64-0.66)) for South compared to North, while in the general population the age and gender standardized RR of death was 0.91. After adjustment for general population mortality in addition to age, gender, and diabetes, the RR of death for patients on RRT in the South changed from 0.65 to 0.74 (95% CI (0.72-0.75)), which indicates that general population mortality accounted for 26% of the region-related mortality difference on RRT. In conclusion, within Europe there exist considerable international differences in the mortality of patients on RRT. Twenty-six percent of the European north-south mortality difference in RRT could be attributed to differences in general population mortality. Our data support the hypothesis that general population mortality is an important factor to take into account when making RRT mortality comparisons.

Polymorphisms in the xylosyltransferase genes cause higher serum XT-I activity in patients with pseudoxanthoma elasticum (PXE) and are involved in a severe disease course

BACKGROUND

Pseudoxanthoma elasticum (PXE) is a heritable connective tissue disorder caused by mutations in the ABCC6 gene. Fragmentation of elastic fibres and deposition of proteoglycans result in a highly variable clinical picture. The altered proteoglycan metabolism suggests that enzymes from this pathway function as genetic co-factors in the severity of PXE. Therefore, we propose the XYLT genes encoding xylosyltransferase I (XT-I) as the chain-initiating enzyme in the biosynthesis of proteoglycans and the highly homologous XT-II as potential candidate genes.

METHODS

We screened all XYLT exons in 65 German PXE patients using denaturing high performance liquid chromatography and analysed the influence of the variations on clinical characteristics.

RESULTS

We identified 22 variations in the XYLT genes. The missense variation p.A115S (XT-I) is associated with higher serum XT activity (p = 0.005). The amino acid substitution p.T801R (XT-II; c.2402C>G) occurs with significantly higher frequency in patients under 30 years of age at diagnosis (43% v 26%; p = 0.04); all PXE patients with this variation suffer from skin lesions compared to only 75% of the wild type patients (p = 0.002). c.166G>A, c.1569C>T, and c.2402C>G in the XYLT-II gene were found to be more frequent in patients with higher organ involvement (p = 0.04, p = 0.01, and p = 0.02, respectively).

CONCLUSIONS

Here we show for the first time that variations in the XYLT-II gene are genetic co-factors in the severity of PXE. Furthermore, the higher XT activity in patients with the exchange p.A115S (XT-I) indicates that this polymorphism is a potential marker for increased remodelling of the extracellular matrix.

Novel sequence variants in the human xylosyltransferase I gene and their role in diabetic nephropathy

AIMS

Decreased content of heparan sulphate proteoglycans (HSPGs) is a characteristic of the glomerular basement membrane (GBM) in diabetes and contributes to the development of diabetic nephropathy (DN). Xylosyltransferase I (XT-I) is the chain-initiating enzyme involved in the biosynthesis of HSPGs. This study investigated a possible association between XYLT-I sequence variants and susceptibility to DN.

METHODS

Screening of all XYLT-I exons was performed in 74 caucasians with Type 1 diabetes (48 with and 26 without DN) and in 13 non-diabetic control subjects using denaturing high-performance liquid chromatography.

RESULTS

Fifteen XYLT-I sequence variants were identified. Of these, six were previously unknown. There were significant differences in the allele frequencies of the three polymorphisms (c.343G-->T (p.A115S), IVS3+10C-->T, IVS3+30G-->C) in Type 1 diabetic patients and healthy controls.

CONCLUSIONS

The occurrence of DN is independent of the XYLT-I variants detected in our study. However, three XYLT-I polymorphisms may be linked to Type 1 diabetes. Since we have previously proposed that one of these polymorphisms was not associated with Type 1 diabetes (Schön S et al. Kidney Int 2005; 68: 1483-1490), larger-scale analysis is clearly necessary to pinpoint the significance of this mutation.

Mutational and functional analyses of xylosyltransferases and their implication in osteoarthritis

OBJECTIVE

The hallmark in osteoarthritis (OA) is the loss of proteoglycans (PGs) in articular cartilage (AC). Xylosyltransferase I (XT-I) catalyzes the transfer of xylose to serine residues in the core protein and initiates the biosynthesis of PGs in AC. The XYLT-II gene encodes a highly homologous protein but its biological function is not yet known. Here we investigate for the first time genetic variations in the XYLT-genes and serum XT-I activities and their implication in OA.

METHODS

Denaturing high-performance liquid chromatography (DHPLC) was used for the screening of the XYLT-genes in 49 OA patients. For a detailed characterization of XT-I amino acid exchanges we performed recombinant expression of XT-I mutants in insect cells. Furthermore, the XT activity was measured in the patients' serum.

RESULTS

The variation c.1569C>T (XYLT-II) occurs with a significantly higher frequency in younger OA patients in comparison with the older ones (P<0.001) and the controls (P<0.02). Furthermore, significantly higher serum XT activities were found in patients with a long disease duration of OA (P<0.04). The recombinant XT-I mutants p.P385L and p.I552S had reduced enzymatic activity (85% and 74%) compared with the wildtype (wt).

CONCLUSIONS

Our findings indicate a correlation of the c.1569 T-allele in XYLT-II with an earlier manifestation of OA and that the serum XT activity is a potential biochemical marker for staging and monitoring the progression of AC damage in OA. Comparison of XT-I activity in mutant enzymes in vivo and in vitro revealed that heterozygous mutations are not involved in OA.

Fluoride semiconductor saturable-absorber mirror for ultrashort pulse generation

We demonstrate what is to our knowledge the first ultrabroadband monolithically grown AlGaAs/CaF(2) semiconductor saturable-absorber mirror (SESAM) that covers nearly the entire gain spectrum of a Ti:sapphire laser. A large high-reflectivity bandwidth of more than 300 nm is provided by a device consisting of only six material layers. This fluoride SESAM had a modulation depth of 2.2%, a fast recovery time constant of less than 150 fs, and a slow recovery time constant of 1.2 ps. Using this SESAM inside a Ti:sapphire laser produced self-starting sub-10-femtosecond pulses.

Evaluation of CoaguChek Pro ACT in cardiac catheterization laboratory

The objective of this study was to assess the analytical performance of CoaguChek Pro ACT assay versus Hemochron Celite ACT assay concerning activated clotting time (ACT) values and the correlations versus heparin. Enrolled were 158 patients and 101 normal subjects from five cardiac catheterization laboratories (cathlabs). Two different CoaguChek Pro ACT lots were compared to different lots of Hemochron Celite ACT. All sites used arterial blood and one site also used venous blood. Determinations were carried out before and directly after heparinization, and 1-4 h later. Besides the ACT values, hematocrit, platelet counts and factor Xa levels were also determined. The correlations between the Hemochron Celite lots and the two different CoaguChek Pro lots for arterial and venous blood for all sites were good (r=0.88 and 0.84). The agreement between both CoaguChek Pro ACT lots was excellent (r=0.99). The correlations between heparin and CoaguChek Pro ACT were similar to those for the Hemochron Celite lots. There was no influence of the hematocrit and the platelets. The imprecision of the method was very good (CV<6%). This demonstrates that the CoaguChek Pro ACT assay is especially useful for monitoring heparin in cathlabs.

Endometrial carcinoma: immunohistochemically detected proliferation index is a prognosticator of long-term outcome

AIM

To test which immunohistochemically detected tumour parameters are predictive of outcome in endometrial carcinoma.

METHODS

A retrospective study of 300 patients diagnosed with endometrial carcinoma between 1980 and 1985, ensuring a follow up of at least 10 years. Paraffin wax embedded tissues from 236 patients with endometrial carcinoma were evaluated in terms of histological tumour type and grade, stage of disease, and certain immunohistochemical biological parameters. These parameters included the expression of oestrogen and progesterone receptors, the expression of p53 protein, the expression of the c-erbB-2 oncoprotein, and the expression of protease cathepsin D, together with the rate of cell proliferation.

RESULTS

Using univariate analysis, the following parameters correlated significantly with adjusted survival: histological type (p = 0.025), grade (p = 0.00003), FIGO stage (p < 0.00001), proliferation rate (p = 0.00002), oestrogen receptor expression (p = 0.007), progesterone receptor expression (p = 0.0092), and p53 expression (p = 0.00028). These parameters also correlated significantly with both disease free and overall survival. There was a weak correlation of cathepsin D expression with survival, but no correlation of c-erb B-2 expression with survival. Using multivariate analysis, only FIGO stage (p = 0.0021), histological grade (p = 0.005), and proliferation rate (p = 0.0007) remained statistically significant prognosticators of adjusted survival as well as of disease free and overall survival.

CONCLUSIONS

In addition to conventional histological parameters, the immunohistochemical determination of proliferative activity could contribute to the identification of a high risk subgroup of endometrial carcinomas. The other parameters tested were not of significant additional predictive value.

[Cerebral sinus thrombosis: rapid test diagnosis by demonstration of increased plasma D-dimer levels (SimpliRED)]

PURPOSE

To perform an initial evaluation of the accuracy in detection of dural sinus and cerebral venous thrombosis using a bed-side test (SimpliRED).

MATERIAL AND METHODS

Early diagnosis and treatment of cerebral sinus thrombosis are important. A screening test to decide which patients should undergo further diagnostics would be valuable due to the low incidence. Six patients with MR proven cerebral sinus thrombosis underwent bed-side testing. The SimpliRED kit provides a clearly visible agglutination of the patient's red blood cells in the presence of elevated levels of the crosslinked fibrin derivative (D-dimer) in the sample.

RESULTS

The assay yielded a positive result in all six patients, even 56 days following the onset of clinical symptoms.

CONCLUSION

The sensitivity of SimpliRED in the detection of sinus venous thrombosis is not known. This assay, therefore, should be evaluated in a large prospective study. In addition, the capability of the test to assess the effect of and predict the duration of anticoagulation therapy should be considered.

[Rate of proliferation as a prognostic criterion in endometrial carcinoma--an immunohistochemical analysis with the monoclonal antibody KI-S1]

In a subset of 183 primarily operative treated patients of 300 patients with endometrial carcinoma an analysis of histological tumor type (n = 142), myometrial invasion (n = 115), stage (n = 114), immunohistochemically detected steroid receptor status, histologic grading (n = 152) and growth fraction, detected by immunohistochemical determination of antibody Ki-S1 (n = 130), was performed. The mean follow up was 9.1 years. By univariate analysis, age, myometrial invasion (< = 3/>3 mm), expression of steroid receptor, FIGO-stage, histologic grading and growth fraction were found to influence the overall survival rate significantly. Cox multivariate regression showed age, FIGO-stage and growth fraction to be independent predictors of overall survival. With respect to survival univariate analysis revealed progesterone receptor status, FIGO-stage, histologic grading and growth fraction as prognostic factors. By multivariate analysis FIGO-stage, histologic grading and growth fraction were found to be independent prognostic factors for survival. Multivariate and univariate analysis exhibited FIGO-stage, histologic grading and growth fraction rate to be independent predictors of a disease-free survival. Immunohistochemically detected growth fraction seems to be useful as an additional prognostic factor in endometrial cancer.

[ACPA reaction in atypical Wegener's disease. Diagnostic test]

Clinical and biopsy findings in six patients (aged 29-64 years), suspected of having Wegener's granulomatosis, were not diagnostic. Cardinal signs were skin necroses, isolated deficits of cranial nerves, sudden amaurosis, renal failure with shunt sepsis and lung opacities suspicious of tumour. Only positive tests for anti-cytoplasmatic antibodies (ACPA) in serum made the diagnosis and led to appropriate treatment. This simple yet highly specific immunofluorescence test should be performed in every case of vasculitis of uncertain cause, even if typical clinical signs of Wegener's granulomatosis are at first absent.

[An unusual slow course of systemic vasculitis with multiorgan involvement]

This paper reports on an unusually slowly progressing course seen in systemic vasculitis of the median and smaller arteries and small veins associated with dermatomyositis, chronically active hepatitis, glomerulonephritis of the immune complex and restrictive cardiomyopathy in a 35-year-old patient. The authors discuss the difficulties in establishing the diagnosis and in finding the exact classification of this disease.

Effect of myocardial perfusion and metabolic interventions on cardiac kinetics of phenylpentadecanoic acid (IPPA) I 123

The effect of regional myocardial perfusion and flow-independent adrenergic stimulation, as well as lactate-mediated inhibition of cardiac lipolysis, on cardiac IPPA uptake and metabolism was examined in canine hearts (flow studies) and in the isolated perfused Langendorff rat heart (metabolic interventions). In both normal and ischaemic myocardium, local perfusion is a major determinant of cardiac IPPA uptake. In pacing-induced hyperaemia, the strict flow-dependence of cardiac IPPA uptake is not preserved. Adrenergic stimulation raises the rate of oxidation of both palmitic acid 14C and IPPA. This change is reflected by increased metabolite production released into the perfusate and radioactivity clearance recorded externally. Lactate in high concentrations exerts the opposite effect on cardiac free fatty acid oxidation. IPPA is stored in this condition preferentially in tissue phospholipids and triglycerides.

Relation of myocardial blood flow and initial cardiac uptake of 15-(p-123I-phenyl)-pentadecanoic acid in the canine heart

In 8 pentobarbital-anesthetized mongrel dogs the correlation between regional myocardial blood flow (RMBF) and regional cardiac uptake of 15-(p-123I-phenyl)-pentadecanoic acid (IPPA) was determined. Three animals were studied under control conditions, in three dogs an acute ischemia was produced by LAD ligation, and two dogs were paced at 195 beats/min. RMBF values were 20-50 ml/min X 100 g in acutely ischemic myocardium. 90-120 ml/min X 100 g under normal conditions and 200-250 ml/min X 100 g during pacing-induced stimulation. Total cardiac uptake of IPPA was 4.5-6% of the injected dose. In normal and acutely ischemic myocardium a good correlation between RMBF and IPPA uptake was obtained. Under stimulated conditions only a moderate increase of IPPA accumulation was found. At RMBF values above 150-170 ml/min X 100 g an upper limit of IPPA uptake was observed and can be explained by limited diffusion or an increased utilization of alternative substrates.