Hepatosplenic candidiasis in patients with hematological malignancies: a 13-year retrospective cohort study

Background

Hepatosplenic candidiasis (HSC) used to be reported in patients with acute myeloid leukemia (AML) without antifungal prophylaxis. The aim was to describe the clinical features and outcomes of HSC over the last 13 years in a single French hematology center.

Methods

All patients diagnosed with HSC between 2008 and 2020 were included in a single-center retrospective cohort study. Data were collected from patient charts, and HSC was classified according to the 2020 European Organisation for Research and Treatment of Cancer/Mycoses Study Group definitions.

Results

Sixty patients were included, with 18.3% proven, 3.3% probable, and 78.3% possible HSC according to the 2020 European Organization for Research and Treatment of Cancer Mycoses Study Group classification. Among them, 19 patients were treated for acute myeloid leukemia (AML), 21 for lymphomas, and 14 for acute lymphoblastic leukemia. HSC occurred in 13 patients after autologous stem cell transplantation for lymphoma. At HSC diagnosis, 13 patients were receiving antifungal prophylaxis. Candida colonization was present in 84.2%, with prior candidemia in 36.7% of cases. β-D-glucans was positive in 55.8%, and 45.8% of tissue biopsies were contributive. First-line antifungal therapy was azoles in 61.7%, and steroids were associated in 45% of cases. At 3 months of follow-up, partial response to antifungal therapy was 94.2%. At last follow-up (mean, 22.6 months), 41 patients (68.3%) presented a complete hematological remission and 22 patients were deceased, none because of HSC.

Conclusions

The epidemiology of HSC has changed in the last decade, with fewer cases occurring in the AML setting. A better identification of patients at risk could lead to specific prophylaxis and improved diagnosis.

How to screen and diagnose deep venous thrombosis (DVT) in patients hospitalized for or suspected of COVID-19 infection, outside the intensive care units

Introduction

The Coronavirus disease-2019 outbreak (COVID-19) has been declared a pandemic by the World Health Organization. Studies report both a severe inflammatory syndrome and a procoagulant state in severe COVID-19 cases, with an increase of venous thromboembolism, including pulmonary embolism (PE) and deep vein thrombosis (DVT). In this context, we discuss the use of doppler ultrasonography (DUS) in the screening and diagnosis of DVT in ambulatory and hospitalized patients with, or suspected of having, COVID-19, outside the intensive care unit (ICU).

Material and methods

Non-systematic review of the literature.

Results

In patients hospitalized for or suspected of COVID-19 infection with the presence of either (a) DVT clinical symptoms, (b) a strong DVT clinical probability (Wells score > 2) or (c) elevated D-dimer levels without DVT clinical symptoms and without PE on lung CT angio-scan, DVT should be investigated with DUS. In the presence of PE diagnosed clinically and/or radiologically, additional systematic DVT screening using DUS is not recommended during the COVID-19 pandemic. The use of 4-points compression DUS for DVT screen and diagnosis is the most appropriate method in this context.

Discussion

Systematic DUS for DVT screening in asymptomatic COVID patients is not recommended unless the patient is in the ICU. This would increase the risk of unnecessarily exposing medical staff to SARS-CoV-2 and monopolizing limited resources during this period.

Late toxicities and clinical outcome at 5 years of the ACCORD 12/0405-PRODIGE 02 trial comparing two neoadjuvant chemoradiotherapy regimens for intermediate-risk rectal cancer

Background

Outcome of intermediate risk rectal cancer may be improved by the addition of oxaliplatin during 5-fluoruracil concomitant neoadjuvant chemoradiotherapy. The purpose of this study is to analyze the main clinical results of the ACCORD12 trial (NCT00227747) in rectal cancer after 5 years of follow-up.

Patients and methods

Inclusion criteria were as follows: rectal adenocarcinoma accessible to digital examination staged T3-T4 Nx M0 (or T2 Nx distal anterior rectum). Two neoadjuvant chemoradiotherapy regimens were randomized: CAP45 (RT 45 Gy + capecitabine) and CAPOX50 (RT 50 Gy + capecitabine and oxaliplatin). Main end point was sterilization of the operative specimen. Acute and late toxicities were prospectively analyzed with dedicated questionnaires.

Results

Between November 2005 and July 2008, 598 patients were included in the trial. After a median follow-up of 60.2 months, there was no difference between treatment arms in multivariate analysis either for disease-free survival or overall survival (OS) [P = 0.9, hazard ratio (HR)=1.02; 95% confidence interval (CI), 0.76-1.36 and P = 0.3, HR = 0.87; 95% CI, 0.66-1.15, respectively]. There was also no difference of local control in univariate analysis (P = 0.7, HR = 0.92; 95% CI, 0.51-1.66). Late toxicities were acceptable with 1.6% G3 anal incontinence, and <1% G3 diarrhea, G3 rectal bleeding, G3 stenosis, G3-4 pain, G3 urinary incontinence, G3 urinary retention and G3 skeletal toxicity. There was a slight increase of erectile dysfunction over time with a 63% rate of erectile dysfunction at 5 years. There was no significant statistical difference for these toxicities between treatment arms.

Conclusions

The CAPOX50 regimen did not improve local control, disease-free survival and overall survival in the ACCORD12 trial. Late toxicities did not differ between treatment arms.

Evaluation of ECG Interpretation Results Obtained by Computer and Cardiologists

In an international project investigators from 25 institutes are trying to establish a common reference library and evaluation methods for testing the diagnostic performance of various ECG computer programs and of cardiologists, based on ECG-independent clinical information. A first set of 500 validated ECGs was collected and analyzed by fifteen different computer programs and nine cardiologists, seven of who analysed the ECG and five the VCG. A coding scheme was used to map individual diagnostic statements onto a common set. Combined program and referee results were obtained by weighted averaging. Preliminary results indicate that the classification accuracy of several programs can still be improved. However, it was also apparent that the results of the best 12-lead ECG computer programs proved to be almost as accurate as the best of seven cardiologists in classifying seven main disease categories, i.e., normal, left, right and biventricular hypertrophy, anterior, inferior and combined myocardial infarction. Evaluation of rhythm statements and conduction disturbances was not included in the study. The data collection is still being pursued in order to reach over 1,000 cases. In this way a common diagnostic database is being established for comparative testing of diagnostic computer programs. This should lead to consumer protection and improve the accuracy and reliability of computerized electrocardiography.

Decision-making in fecal occult blood test compliance: A quali-quantitative study investigating motivational processes

The qualitative-quantitative study investigates the co-existence of barriers and levers to FOBT screening in 5894 individuals reluctant to be screened, identifying operational motivational patterns that may increase screening compliance. Co-occurrence analysis was performed according to three motivational conditions (barriers, levers, or both).Cluster analysis then identified motivational predictors of effective screening. One quarter of the individuals who had refused screening nevertheless expressed at least one motivation towards FOBT. As such, co-existence of barriers and levers within the same individual demonstrates ambivalence tendencies. Intrinsic motivations appear to be the most likely to increase FOBT compliance. This study finds that certain factors well-known to improve CRC screening compliance generally, may not have much impact on reluctant individuals due to ambivalence and contextual nuances. Several practical recommendations to encourage screening participation are offered, such as focusing on levers rather barriers, providing tailored education to improve awareness and readiness, and fostering intrinsic motivation with relevant approaches.

Azadirachtin impact on mate choice, female sexual receptivity and male activity in Drosophila melanogaster (Diptera: Drosophilidae)

Azadirachtin, a neem compound (Azadirachta indica) with medical and anti-insect properties, is one the most successful botanical pesticides in agricultural use. However, its controversial impact on non-targeted species and its mechanism of action need to be clarified. In addition, Azadirachtin impact on pre- and post-mating traits remains largely undocumented. The current study examined the effects of Azadirachtin on Drosophila melanogaster as a non-target and model species. Azadirachtin was applied topically at its LD₅₀ (0.63μg) on the day of adult emergence and its effect was evaluated on several traits of reproductive behavior: mate choice, male activity, female sexual receptivity, sperm storage and female sterility. In choice and no choice conditions, only male treatment reduced mating probability. Female treatment impaired mating probability only when males had the choice. Males' mating ability may have been impaired by an effect of the treatment on their mobility. Such an effect was observed in the actimeter, which revealed that treated males were less active than untreated ones, and this effect persisted over 8days. Azadirachtin treatment had, however, no effect on the nycthemeral rhythm of those males. Even when mating occurred, Azadirachtin treatment impaired post-mating responses especially when females or both sexes were treated: remating probability increases and female fertility (presence of larvae) decreases. No impairment was observed on the efficiency of mating, evaluated by the presence of sperm in the spermatheca or the ventral receptacle. Male treatment only had no significant effect on these post-mating responses. These findings provide clear evidence that Azadirachtin alters the reproductive behavior of both sexes in D. melanogaster via mating and post-mating processes.

Prevalence, risk factors, and impact on clinical outcome of extended-spectrum beta-lactamase-producing Escherichia coli bacteraemia: a five-year study

BACKGROUND

The impact of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) bacteraemia on outcome remains controversial.

METHODS

A retrospective analysis of the prevalence, risk factors, clinical features, and outcomes of all ESBL-EC bacteraemia in one French hospital over a 5-year period was performed. A case-control study was undertaken: cases had at least one ESBL-EC bacteraemia and controls a positive non-ESBL-EC bacteraemia.

RESULTS

The prevalence of ESBL-EC bacteraemia increased from 5.2% of all positive E. coli blood cultures in 2005 to 13.5% in 2009 (p<0.003). CTX-M represented 70% of ESBL-EC bacteraemia strains, and strains were not clonally related. On adjusted analysis, the only significant risk factor for ESBL-EC bacteraemia was a previous ESBL-EC colonization (odds ratio 11.3, 95% confidence interval 1.2-107; p=0.003). Initial antimicrobial therapy was less frequently adequate in the ESBL-EC group (48% vs. 85%; p=0.003). The presence of ESBL-EC bacteraemia was not associated with a longer hospital stay (p=0.088). Day 30 mortality was high, but not significantly different in the two groups (30% vs. 27%; p=0. 82).

CONCLUSION

The prevalence of ESBL-EC bacteraemia has been increasing dramatically. Previous colonization with ESBL-EC was a strong risk factor for ESBL-EC bacteraemia. More inadequate initial antimicrobial therapy was noted in the ESBL-EC group, but mortality and length of hospital stay were not significantly different from those of patients with non-ESBL-EC bacteraemia.

Predictors of adherence to repeat fecal occult blood test in a population-based colorectal cancer screening program

Background:

Socio-economic, environmental factors and general practitioner (GP) involvement may influence adherence to repeat faecal occult blood testing (FOBT) of organised colorectal cancer (CRC) screening. The aim of the study was to identify predictors of adherence to repeat testing.

Methods:

The populationcomprised people eligible for the third round of a CRC screening programme in a French district (n=118 905). Multilevel logistic regression analysis was performed to identify individual and area-level characteristics associated with ‘compliant participants' participating in the all three rounds vs ‘occasional participants' participating in one or two rounds.

Results:

Compared to ‘occasional participants', ‘compliant participants' were more likely to participate after receiving a FOBT kit from their GP (odds ratio (OR), 10.7; 95% CI, 10.01–11.5) vs FOBT received at home, and were less likely to live in socio-economically deprived areas (OR, 0.75; 0.70–0.80) and urban areas (OR, 0.94; 0.88–1.00).

Conclusions:

As for a screening round participation, strategies aimed at improving the participation to a screening programme should target GPs and people living in socially deprived areas.

Iterative breakthrough invasive aspergillosis due to TR(34) /L98H azole-resistant Aspergillus fumigatus and Emericella sublata in a single hematopoietic stem cell transplant patient

We report 3 consecutive episodes of invasive aspergillosis in a single hematopoietic stem cell transplant patient successively attributed to TR(34) /L98H azole-resistant Aspergillus fumigatus and to a first occurrence of invasive Emericella sublata infection. This case illustrates potential selection of resistant molds during antifungal therapy in hematological patient.

Interaction between temperature and male pheromone in sexual isolation in Drosophila melanogaster

In Drosophila, female hydrocarbons are known to be involved in premating isolation between different species and pheromonal races. The role of male-specific hydrocarbon polymorphism is not as well documented. The dominant cuticular hydrocarbon (CHC) in male D. melanogaster is usually 7-tricosene (7-T), with the exception of African populations, in which 7-pentacosene (7-P) is dominant. Here, we took advantage of a population from the Comoro Islands (Com), in which males fell on a continuum of low to high levels of 7-T, to perform temperature selection and selection on CHCs’ profiles. We conducted several experiments on the selected Com males to study the plasticity of their CHCs in response to temperature shift, their role in resistance to desiccation and in sexual selection. We then compared the results obtained for selected lines to those from three common laboratory strains with different and homogenous hydrocarbon profiles: CS, Cot and Tai. Temperature selection modified the CHC profiles of the Com males in few generations of selection. We showed that the 7-P/7-T ratio depends on temperature with generally more 7-P at higher temperatures and observed a relationship between chain length and resistance to desiccation in both temperature- and phenotypically selected Com lines. There was partial sexual isolation between the flies with clear-cut phenotypes within the phenotypically selected lines and the laboratory strains. These results indicate that the dominant male pheromones are under environmental selection and may have played a role in reproductive isolation.

[Pulmonary fungal infection in patients with AIDS]

Fungal infections are the most common opportunistic infections (OI) occurring during the course of HIV infection, though their incidence has decreased dramatically with the introduction of highly active antiretroviral therapy (cART). Most cases occur in untreated patients, noncompliant patients or patients whose multiple antiretroviral regimens have failed and they are a good marker of the severity of cellular immunodepression. Pneumocystis jiroveci pneumonia is the second most frequent OI in France and cryptococcosis remains a major problem in the Southern Hemisphere. With the increase in travel, imported endemic fungal infection can occur and may mimic other infections, notably tuberculosis. Fungal infections often have a pulmonary presentation but an exhaustive search for dissemination should be made in patients infected with HIV, at least those at an advanced stage of immune deficiency. Introduction of cART in combination with anti-fungal treatment depends on the risk of AIDS progression and on the risk of cumulative toxicity and the immune reconstitution inflammatory syndrome (IRIS) if introduced too early. Fungal infections in HIV infected patients remain a problem in the cART era. IRIS can complicate the management and requires an optimised treatment regime.

Comparison between a guaiac and three immunochemical faecal occult blood tests in screening for colorectal cancer

BACKGROUND

The aim of this study was to compare the performance of the guaiac-based faecal occult blood test (G-FOBT), with that of three immunochemical faecal occult blood tests (I-FOBT) which allow automatic interpretation.

PATIENTS AND METHODS

Under the French organised screening programme, 85,149 average-risk individuals aged 50-74 participating in the third screening round, performed both the G-FOBT (Hemoccult-II test) and one of the I-FOBTs: FOB-Gold, Magstream and OC-Sensor.

RESULTS

Given the chosen threshold, the positivity ratio between the different I-FOBTs and the G-FOBT was 2.4 for FOB-Gold, 2.0 for Magstream and 2.2 for OC-Sensor (P=0.17). The three I-FOBTs were superior to the G-FOBT for colorectal cancer (CRC) detection. The ratios for detection rates were 1.6 (FOB-Gold), 1.7 (Magstream) and 2.1 (OC-Sensor) (P=0.74). For non-invasive CRC they were, respectively, 2.5, 3.0 and 4.0 (P=0.83) and for advanced adenomas 3.6, 3.1 and 4.0 (P=0.39).

CONCLUSIONS

This study provides further evidence that I-FOBT is superior to G-FOBT. None of the three I-FOBTs studied appeared to be significantly better than the others.

Some diminutive colorectal polyps can be removed and discarded without pathological examination

BACKGROUND AND STUDY AIMS

Pathological examination of colorectal polyps is useful if clinical management is affected (i. e. when invasive carcinoma is detected or postpolypectomy surveillance interval is guided). Our aim was to assess whether the pathological examination of some diminutive (measuring ≤ 5 mm) polyps can be omitted.

PATIENTS AND METHODS

Consecutive patients undergoing a colonoscopy at Pasteur Hospital (Colmar, France) between January and August 2008 were included in this prospective study. Six senior gastroenterologists predicted the future surveillance interval without referring to the result of pathological examination.

RESULTS

In all, 350 polyps from 175 patients were removed and analyzed. The endoscopist was able to predict the correct surveillance interval without referring to the result of pathological examination in 118 patients (67.4 %; 95 % confidence interval [CI] 60.5 - 74.4). The pathological examination of 18.4 % (95 % CI 13.7 - 23.1) of diminutive polyps either associated with a cancer or a polyp measuring ≥ 10 mm or removed in very old or frail patients could be omitted without any consequence for the patient. If diminutive polyps one or two in number were discarded without pathological examination in patients with a personal history of colorectal neoplasm, three patients out of 43 would have a 5-year instead of a 3-year surveillance interval. As a whole, if 44.1 % (95 % CI 38.0 - 50.1) of diminutive polyps were discarded, the surveillance interval would remain identical in 98.3 % (95 % CI 96.4 - 100) of patients.

CONCLUSIONS

The pathological examination of up to 44 % of diminutive polyps (i. e. 33 % of all polyps), can be safely omitted. The pathological examination would be required only for those with suspicious gross appearance, those three or more in number, and those isolated one or two in number that are removed from people without personal history of colorectal neoplasm.

[Type 2 diabetes mellitus prevalence and social inequalities for health]

We have analyzed the relationship between the prevalence of diabetes mellitus (type 2) and socio-economic status of patients. The cross-sectional study included 79,855 patients registered in Belgium capitation-fee primary health care centers. The adjusted prevalence for age and gender was 6.3%, significantly higher than the estimated 4.7% in the general population. The gap is mainly explained by the lower socio-economic status of the patients we take care of. Inside our population we found a 1.8 times higher risk to be affected by diabetes mellitus for patients with lower socio-economic status (95% confidence interval: 1.6-1.9). This higher risk is found for all age groups except for the elderly. Studies should be designed to investigate how that social inequality for health also concern quality of care and therapeutical outcomes.

Ventricular assistance after tricuspid valve replacement for carcinoid heart disease

We report a case of a 71-year-old woman with carcinoid heart disease admitted in ICU after tricuspid valve replacement. She quickly developed a acute heart right failure. Optimal medical treatment failed and we implanted ventricular assistance. After 10 days of support, patient improved and the right ventricle recovered. Temporary devices can provide a successful bridge to cardiac recovery. However, the risk of infection that is a major prognosis factor should be carefully considered particularly when temporary assistance implanted on immunosuppressed patients.

Blood genetic marker studies of a sheep-goat hybrid and its back-cross offspring

Blood samples from a female sheep-goat hybrid and its back-cross male offspring were tested for electrophoretic variants of plasma albumin, transferrin and esterase, and of red cell carbonic anhydrase, nucleoside phosphorylase, NADH-diaphorase, 'X'-protein, superoxide dismutase, malic enzyme and haemoglobin. Red cells were also tested for blood group antigens. Both animals showed variants that could not be attributed to either sheep or goat alone, thus confirming previous chromosomal data that the female was a genuine sheep-goat hybrid.

Compliance and immunogenicity of two hepatitis B vaccination schedules in sex workers in Belgium

OBJECTIVES

To compare the coverage for the third dose and the compliance to two hepatitis B vaccination schedules: 0,1,4 versus 0,1,6 months, in commercial sex workers (CSW) in Belgium; to compare the immunogenicity of the actually administered schedules.

METHODS

In seven health centres in Belgium, hepatitis B vaccination was offered free of charge to CSW. In a randomised, prospective study a commercialised hepatitis B vaccine (Engerix-B 20mcgr) was offered according to one of both schedules. After complete vaccination, bleeding was performed to assess immunogenicity.

RESULTS

Between June 2003 and September 2004, 615 non-immune CSW were enrolled, of whom 52% in the 0,1,4 month schedule (n=322). Coverage of the third dose was 57% overall, 59% (0,1,4) and 54% (0,1,6), respectively. Age, the health centre and drug use significantly influenced the compliance and the coverage of dose 3, whereas the planned vaccination did not. When comparing the immunogenicity results as a function of the actually administered vaccination schedule, immune responses did not significantly differ between CSW receiving the third dose 4-6 months and those receiving it at least 6 months after the first dose. In total, 19 persons (8%) were not protected after a full vaccination course (anti-HBs <10IU/L). Two health centres measured markedly lower anti-HBs levels.

CONCLUSIONS

In this highly mobile at-risk population, a 0,1,4 month schedule is more easy to offer and confers equal protection within a shorter period of time. We therefore propose this 0,1,4 month schedule to vaccinate CSW in the future.

Evidence for a substantial role of sharing of injecting paraphernalia other than syringes/needles to the spread of hepatitis C among injecting drug users

In industrialized countries, transmission of hepatitis C occurs primarily through injecting drug use. Transmission of hepatitis C in injecting drug users is mainly associated with the sharing of contaminated syringes/needles, although evidence for risk of hepatitis C infection through sharing of other injecting paraphernalia is increasing. In this paper, the independent effects of sharing paraphernalia other than syringes/needles have been estimated. The prevalence and force of infection were modelled using three serological data sets from drug users in three centres in Belgium as a function of the sharing behaviour. It was found that sharing of materials other than syringes/needles indeed seemed to contribute substantially to the spread of hepatitis C among injecting drug users.

Impact of cytopathologist expert on diagnosis and treatment of pancreatic lesions in current clinical practice. A series of 106 endoscopic ultrasound-guided fine needle aspirations

OBJECTIVES

To evaluate the role of a cytopathologist expert in interpreting difficult pancreatic endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) in terms of impact on diagnostic yield and therapy in current clinical practice.

METHODS

Retrospective study of 106 EUS-FNA performed between January 2002 and September 2004. Forty-seven cases of difficult interpretation by the local cytopathologist were mailed to an expert cytopathologist. The final diagnosis was established by histology obtained by either surgery (n=30), non-equivocal FNA (n=40) or core (n=8) biopsies, or by a mean follow-up of 14 months (n=28).

RESULTS

EUS-FNA involved 68 solid lesions (SL). Specimens collected were adequate in 63%. The overall sensitivity of EUS-FNA for the diagnosis of malignancy of SL was 88% versus 72% for local cytopathologist and 89% for expert. EUS-FNA with the reevaluation by expert of 39 SL gave a therapeutic impact in 47% of SL. Thirty-eight cystic lesions (CL) were evaluated. Specimens collected were adequate for cytology in 84% of cases and for biochemistry in 79%. The sensitivity of imaging+EUS-FNA+/-biochemistry for the diagnosis of a surgical CL was 58% with a therapeutic impact in 39.5%.

CONCLUSION

Pancreatic EUS-FNA is an easy technique for experienced endosonographers, which can be safely performed on an outpatient basis. The possibility of mailing difficult cases to an expert cytopathologist increases the diagnostic yield. In these circumstances, EUS-FNA has a therapeutic impact in current practice in nearly one out of two pancreatic lesions.

Phaeochromocytoma treated by en bloc resection including the suprarenal caudal vena cava in a dog

A 10-year-old, neutered male Cairn terrier was examined after experiencing intermittent vomiting of several months' duration and sudden onset of acute depression. Abdominal ultrasound examination revealed an adrenal mass invading the suprarenal part of the caudal vena cava. The vascular invasion could not be corrected so en bloc ligation/excision of the adrenal neoplasm and the suprarenal part of the vena cava was performed. Microscopic examination identified an adrenal phaeochromocytoma. The dog recovered well and had no significant vascular or renal dysfunction at follow-up 20 months after surgery. To the authors' knowledge, this is the first report of a dog surviving long term after resection of the suprarenal caudal vena cava.

High cerebral scyllo-inositol: a new marker of brain metabolism disturbances induced by chronic alcoholism

Cerebral metabolic changes that concur to motor and/or cognitive disorders in actively drinking alcoholics are not well established. We tested the hypothesis that chronic alcoholics exhibit profound alterations in the cerebral metabolism of scyllo-inositol. Brain metabolism was explored in nine actively drinking and 11 recently detoxified chronic alcoholics by in vivo brain (1)H-MRS and in vitro(1)H-MRS of blood serum and cerebrospinal fluid. The cohort was composed of individuals with acute, subacute or chronic encephalopathy or without any clinical encephalopathy. Chronic alcoholism is associated with a hitherto unrecognized accumulation of brain scyllo-inositol. Our results suggest that scyllo-inositol is produced within the central nervous system and shows a diffuse but heterogenous distribution in brain where it can persist several weeks after detoxification. Its highest levels were observed in subjects with a clinically symptomatic alcohol-related encephalopathy. When detected, brain scyllo-inositol takes part in a metabolic encephalopathy since it is associated with reduced N-acetylaspartate and increased creatine. High levels of cerebral scyllo-inositol are correlated with altered glial and neuronal metabolism. Our findings suggest that the accumulation of scyllo-inositol may precede and take part in the development of symptomatic alcoholic metabolic encephalopathy.

Metabolic counterpart of decreased apparent diffusion coefficient during hyperacute ischemic stroke: a brain proton magnetic resonance spectroscopic imaging study

BACKGROUND AND PURPOSE

Recent studies have shown that the brain ischemic area defined by the map of decreased apparent diffusion coefficient (ADC) obtained by diffusion-weighted imaging (DWI) during the first hours of ischemic stroke includes a significant part of ischemic penumbra. We hypothesize that the misjudgment of the final infarct size by ADC mapping may be related to a restricted ability of DWI to capture variations in the intensity of cellular suffering. In an attempt to characterize metabolically the hypoperfused brain parenchyma, we studied the relationship between ADC values and brain metabolic parameters measured by proton MR spectroscopic imaging (SI).

METHODS

Six patients with hyperacute ischemic stroke were explored within the first 7 hours after onset with the use of a MR protocol including T2*-weighted MRI, DWI, SI, perfusion-weighted imaging, and MR angiography.

RESULTS

This study demonstrates, for the first time, a wide gradient of ischemia-related metabolic anomalies within the abnormal area delineated by DWI during hyperacute ischemic stroke. In the narrow range of decreased mean ADC values (0.60 to 0.40 x 10(-9) m2 x s(-1)), a 33% decrease in mean ADC is associated with a 122% increase in lactate/N-acetyl aspartate ratio. Mean ADC values never fall below 0.40 x 10(-9) m2 x s(-1) within the severely affected ischemic tissue, while SI still detects a large metabolic heterogeneity inside areas showing similar decreased mean ADC values close to this threshold.

CONCLUSIONS

Our results indicate that the region of very low mean ADC values observed during hyperacute ischemic stroke contains areas of various tissue damage intensity characterized by SI in relation to different stages of cellular metabolic injury. This observation may explain why ADC mapping does not reliably predict final infarct size.

Regional metabolite levels of the normal posterior fossa studied by proton chemical shift imaging

MR spectroscopy of the posterior fossa is pitted with numerous technical difficulties. It is, however, of great clinical interest in the study of the degenerative diseases and tumors of this area. We have developed a method to perform 2D CSI of this area, by using a sagittal slice and a careful positioning of outer volume saturation. We performed this acquisition in 30 healthy volunteers to determine the normal metabolic ratios in five voxels of this area (mesencephalon, pons, medulla oblongata, vermis, cerebellar white matter). The main technical difficulty was magnetic field inhomogeneity in the lower brainstem generated by dental alloys. However, 88% of the voxels were of sufficient quality to be analyzed. The statistically significant regional variations were a higher NAA/Cr ratio in the pons than in the medulla oblongata, higher Cho/Cr in the pons than in the mesencephalon and higher Cho/Cr in the cerebellar white matter than in the vermis. We conclude that 2D CSI of the brainstem, although technically delicate can be performed in most patients.

Long synthetic peptides as biologically active proteins: the example of the chemokines

Chemokines constitute an expanding protein family of over 40 members which exhibit a wide variety of biological activities and are involved in many normal physiological processes, such as cellular migration, differentiation and activation, but also in pathological situations, such as inflammation and metastasis. Over the last few years, we have developed methods to manufacture long synthetic peptides of up to 130 residues, and to achieve the formation of native-like cysteine pairings. This ability prompted us to undertake the total chemical synthesis of chemokines. So far, we have successfully produced over 30 chemokine species, which exhibit biological activities similar to, or greater than, those reported by others. Chemical synthesis offers a clear advantage over recombinant technologies for the introduction of fluorochromes and haptens at molecularly defined positions. In addition, approval of chemically synthesized products for use in humans is straightforward compared with material produced by biological methods.

Thiopalmitoylation of myelin proteolipid protein epitopes enhances immunogenicity and encephalitogenicity

Proteolipid protein (PLP) is the most abundant protein of CNS myelin, and is posttranslationally acylated by covalent attachment of long chain fatty acids to cysteine residues via a thioester linkage. Two of the acylation sites are within epitopes of PLP that are encephalitogenic in SJL/J mice (PLP(104-117) and PLP(139-151)) and against which increased immune responses have been detected in some multiple sclerosis patients. It is known that attachment of certain types of lipid side chains to peptides can result in their enhanced immunogenicity. The aim of this study was to determine whether thioacylated PLP peptides, as occur in the native protein, are more immunogenic than their nonacylated counterparts, and whether thioacylation influences the development of autoreactivity and experimental autoimmune encephalomyelitis. The results show that in comparison with nonacylated peptides, thioacylated PLP lipopeptides can induce greater T cell and Ab responses to both the acylated and nonacylated peptides. They also enhanced the development and chronicity of experimental autoimmune encephalomyelitis. Synthetic peptides in which the fatty acid was attached via an amide linkage at the N terminus were not encephalitogenic, and they induced greater proportions of CD8+ cells in initial in vitro stimulation. Therefore, the lability and the site of the linkage between the peptide and fatty acid may be important for induction of encephalitogenic CD4+ T cells. These results suggest that immune responses induced by endogenous thioacylated lipopeptides may contribute to the immunopathogenesis of chronic experimental demyelinating diseases and multiple sclerosis.