[Ameloblastoma of the jaws. A retrospective analysis from 1994 to 2007]. / Améloblastomes des mâchoires. Analyse rétrospective de 1994 à 2007.

INTRODUCTION: Ameloblastomas and keratocysts are the most frequent epithelial odontogenic tumors of the jaws. They have a high recurrence rate. This retrospective study reviews the features of ameloblastomas operated on in our unit from 1994 to 2007. PATIENTS AND METHODS: The studied parameters were sex, ethnic origin, age at diagnosis, clinical signs, radiographic presentation, site distribution, histological type, treatment, and follow-up records. RESULTS: One hundred and sixteen patients were included (with 239 surgical samples). The mean age was 36 years, with a majority of Europeans, 60% of multilocular radiolucent lesions with root resorption, mandibular location (93%). Twenty-one percent of the patients presented with an impacted tooth, the third molar in 79% of cases. Fifty percent of the lesions were from 5 to 13cm in length, 10% longer than 13cm. The most common histological type was follicular ameloblastoma. Patients were treated by enucleation in 82% of cases and radical mandibular resection with reconstruction in 11% of cases. The follow-up was documented for 96% of the patients with a 44% recurrence rate. Seventy-four percent of patients with a double recurrence presented with a "follicular" ameloblastoma. DISCUSSION: We prefer a well-performed enucleation which preserves surrounding bone. The high rate of follicular type recurrence should more systematically lead to a combined treatment: periostectomy and tooth extraction. Our data was compared with previously published large series.

Isolation of alkane-degrading bacteria from deep-sea Mediterranean sediments.

AIMS: To isolate and identify alkane-degrading bacteria from deep-sea superficial sediments sampled at a north-western Mediterranean station. METHODS AND RESULTS: Sediments from the water/sediment interface at a 2400 m depth were sampled with a multicorer at the ANTARES site off the French Mediterranean coast and were promptly enriched with Maya crude oil as the sole source of carbon and energy. Alkane-degrading bacteria belonging to the genera Alcanivorax, Pseudomonas, Marinobacter, Rhodococcus and Clavibacter-like were isolated, indicating that the same groups were potentially involved in hydrocarbon biodegradation in deep sea as in coastal waters. CONCLUSIONS: These results confirm that members of Alcanivorax are important obligate alkane degraders in deep-sea environments and coexist with other degrading bacteria inhabiting the deep-subsurface sediment of the Mediterranean. SIGNIFICANCE AND IMPACT OF THE STUDY: The results suggest that the isolates obtained have potential applications in bioremediation strategies in deep-sea environments and highlight the need to identify specific piezophilic hydrocarbon-degrading bacteria (HCB) from these environments.

Laparoscopic resorbable mesh fixation. Assessment of an innovative disposable instrument delivering resorbable fixation devices: I-Clip(TM). Final results of a prospective multicentre clinical trial.

BACKGROUND: The aim of this study was to assess the performance and tolerance of an innovative disposable instrument delivering resorbable clips (I-Clip, Sofradim, France) intended for mesh fixation in inguinal, incisional and umbilical hernias of the abdominal wall. The fixation device was designed to be resorbable in 1 year, with reduced trauma to the underlying tissues or the mesh, and with initial mechanical properties equivalent to those of conventional metal staples. METHODS: The study involved 105 patients with inguinal, umbilical or incisional hernias enrolled from 11 centres. Inguinal totally extra peritoneal (TEP) or trans abdomino pre-peritoneal (TAPP) repair was performed with Parietex mesh, incisional or umbilical hernias were treated via the intraperitoneal route with Parietex composite. I-Clips were used for mesh fixation in both indications according to the surgeon's habits. Efficacy was the principal assessment criteria evaluated by two parameters: quality of fixation evaluated subjectively at the time of procedure and recurrence rate according to the follow up at 1, 6 and 12 months. Pain evaluated by the patients using a visual analogue scale (VAS) was the principal secondary assessment criteria. Other tolerance criteria were also evaluated during surgery and follow up. RESULTS: The surgeons' evaluation of the fixation quality was assessed as good to very good in 100% of ventral hernias and good to very good in 85-92% of inguinal hernias. At 1 month, 90% of patients (94/104) were totally pain-free (VAS score: 0) and only ten patients reported low pain (VAS scores: 0.3-3.1). At 1 year, the pain described by those ten patients finally disappeared, 98% of patients (102/104) were totally pain-free. The rate of minor complications not related to the device concerned 5% of the patients at 1 month, which was reduced to 2% at one year and no recurrence or mesh sepsis was observed. CONCLUSIONS: The ease of use of this device, combined with the absence of recurrence related to the investigated device and the good pain-free outcome in this group of patients confirmed the effectiveness and tolerance of the resorbable fixation concept of I-Clip(TM).

[How to avoid research misconduct - recommendations for surgeons]. / Comment éviter la non-conformité de la recherche biomédicale? Recommandations aux chirurgiens.

Research misconduct is defined by the Royal College of Physicians of Edinburgh as any behaviour by a researcher, whether intentional or not, that fails to scrupulously respect high scientific and ethical standards. Various types of research misconduct include fabrication or falsification of data, plagiarism, problematic data presentation or analysis, failure to obtain ethical approval by a research ethics committee or to obtain the subject's informed consent, inappropriate claims of authorship, duplicated publication, and undisclosed conflicts of interest. These can result in patient injury, deterioration of the patient-physician relationship, loss of public trust in biomedical research, as well as pollution/degradation of the medical literature. Surgical research malfeasance has been underreported, and no practical guidelines for good research and publication have appeared to date in French surgical journals. In an attempt to uphold the scientific integrity of our profession, we discuss research misconduct and emphasise preventive measures and considerations for surgeons.

Endoscopic excision of forehead lipomas.

Endoscopic surgery is a significant addition in the maxillofacial surgeon's armamentarium. Authors' experience of endoscopically assisted removal of forehead lipomas has been presented. The endoscopic technique permits to hide minimal scars in the hair. The magnification allows a good identification of anatomical structures and thus decreases the risk of numbness. The main disadvantages of this technique are the more expensive equipment and the steep learning curve. But with the expansion of endoscopic techniques, prices should decline and the duration of operations always lessens with experience. This technique might possibly appear to offer a new standard procedure for removal of forehead lipomas, notably in patients with keloid history or high aesthetic concerns.

Facial malignant peripheral nerve sheath tumors.

BACKGROUND/PURPOSE: Malignant peripheral nerve sheath tumors (MPNSTs) are rare neoplasms, only sporadically reported involving the maxillo-mandibular region (ten cases with CT or MR data). We present here five additional cases with CT and MR findings along with an extensive review of the literature. RESULTS: Accurate diagnosis of MPNSTs is difficult because pathological like radiological criteria are often non specific. Radiological features display a large spectrum of abnormalities from a well-delineated heterogeneous appearance simulating benign schwannoma to extensive erosive patterns. Their development along the mandibular nerve, the absence of any target or central dot sign, their strong predominant peripheral enhancement must suggest the diagnosis of MPNSTs while irregular bone destruction or the detection of poorly defined margins with muscular infiltration are the most reliable criteria of malignancy. Unfortunately, MPNSTs also display a considerably varied histology. Careful clinical and radiological correlation should bring pathologists to examining large samples of the lesion to better evaluate the overall organisation of the lesion and detect some evocative criteria often only present in some areas of the sample as the peculiar curlicue or whorled arrangement of the spindle cells or the alternation of densely cellular fascicles with hypocellular, myxoid zones. Focal, limited immunostaining for S-100 protein is one of the most important additional criterion. CONCLUSION: If accurate early diagnosis often remains difficult, careful correlation of clinical, pathological and radiological data should in most cases suggest a diagnosis of MPNSTs which display a poor prognosis and requires early and adapted treatment.

[Hydrocarbon metabolism in a marine bacterium]. / Métabolisme des hydrocarbures chez une bactérie marine

The marine bacterium L.16.1 (Alcaligenes sp.) grows preferentially on alkanes (C10 to C18) with a very high growth yield (98 per cent); optimal growth depends strictly on the presence of a well-defined NaCl concentration (100 mM). Our strain is constitutive for the enzymatic systems responsible for the oxidation of alkanes to fatty acids, i.e. NADH-dependent hydroxylase, alcohol and aldehyde dehydrogenases, the latter of which located at the cytoplasmic membrane level. The aerobic oxidation of primary alcohols by particulate extracts prepared in the presence of 400 mM NaCl is NAD+-dependent (Km = 0.082 mM, Vmax = 238 with decanol). With extracts prepared in the absence of NaCl, Vmax undergoes a very strong decrease. On the contrary , the NAD+ (P)+-dependent oxidation of aldehydes is carried out anaerobically by the same extracts irrespective of the presence or the absence of added Na+ in the solutions used for the preparation of these extracts. A possible explanation for our results could be that Na+ acts on the enzymatic systems for which the maintenance of the membrane integrity is essential. This interpretation is consistent with the slowing down of the growth speed accompanying the decrease of NaCl concentration in the growth medium. With regard to alcohol and aldehyde-dehydrogenases, it is noteworthy that these enzymes behave like similar enzymatic activities induced by alkanes in other microorganisms.

Isolation and characterization of cytochrome b5 from Candida tropicalis grown on alkane.

Cytochrome b5 from Candida tropicalis grown on alkane has been solubulized in three different ways (sodium cholate, trypsin, osmotic wash). After solubilization of the microsomal membrane with sodium cholate, the purification of cytochrome b5 was achieved by DEAE-cellulose chromatography, hydroxylapatite chromatography, a second DEAE-cellulose chromatography and a Sephadex G-75 gel filtration. The purified protein had an apparent molecular weight of 16 000 +/- 1 000. After solubilization by trypsin treatment or osmotic wash, the purification procedure yielded a protein with an apparent molecular weight of 12 000 +/- 1 000. Though the purified proteins presented molecular weights depending on the technique of solubilization, they exhibited identical optical properties, a great stability with respect to temperature and pH, and were all autooxidable. Redox titrations revealed differences in their midpoint potential values, which were 35 +/- 5 mV for the b5 purified after cholate solubilization, -59 +/- 5 mV for the b5 purified after trypsin treatment and -65 +/- 5 mV for the b5 purified after osmotic wash.

Influence of oxygen on the microsomal electron transport system in Saccharomyces cerevisiae.

The influence of oxygen on the level of microsomal electron transport chain components has been studied during the growth of Saccharomyces cerevisiae. Enzyme activities and cytochrome content were assayed in microsomal fractions prepared from a protoplast lysate free from mitochondrial contamination. It was found that the cytochrome P-450 and cytochrome b5 content, to get her with the NADPH-cytochrome (P-450)-reductase and NADH-cytochrome (b5)-reductase activities, were increased in the cells as the pO2 of the medium was decreasing. At the same time an increase in the membrane surface of the endoplasmic reticulum can be observed.

Evaluation of D-dimer ELISA test in elderly patients with suspected pulmonary embolism.

STUDY OBJECTIVE: To determine the clinical usefulness of D-dimer ELISA test in elderly patients with clinically suspected pulmonary embolism (PE). DESIGN: Prospective cohort study. PATIENTS: Ninety-six consecutive outpatients older than 70 years with a duration of symptoms shorter than one week and without metastatic cancer or recent surgery, trauma, infection, stroke, myocardial infarction, deep vein thrombosis (DVT) or PE, or treatment with curative doses of heparin or oral anticoagulant. INTERVENTION: All patients underwent at least ventilation/perfusion scan and bilateral ultrasonic duplex scan and a blood sample collection within 24 hours of admission. When necessary a pulmonary angiography and/or a bilateral venography were also performed. Patients were classified as follows: (1) PE-positive: positive angiography or high probability V/Q scan and deep vein thrombosis (proven either by venography or by ultrasonic duplex scan) or non high probability V/Q scan and either DVT (proven at presentation by venography or by ultrasonic duplex scan) or symptomatic thromboembolic event within 3 months of follow-up; or (2) PE-negative; normal V/Q scan or normal angiography or non high probability V/Q scan and either negative ultrasonic duplex scan or normal venography and low clinical probability and absence of symptomatic thromboembolism within 3 months of follow-up. D-dimer measurements were performed using both a conventional and a single semi-quantitative ELISA test (Asserachrom D-di, Instant I.A.D-dimer). RESULTS: Using a cutoff value of 500 ng/ml, the conventional ELISA D-dimer test showed a sensitivity and a negative predictive value of 100% with poor specificity and positive predictive value of 14.3% and 45.5% respectively. The new rapid semi-quantitative D-dimer test displays worse results with sensitivity, negative predictive value, specificity and positive predictive value of 92.3%, 82.4%, 25% and 46% respectively. CONCLUSION: In a geriatric population, conventional ELISA D-dimer is a good marker to exclude PE but, due to the comorbid conditions, only a few patients presented with D-dimer values less than 500 ng/ml.

Salt requirements in the denitrifying bacterium Pseudomonas nautica 617.

Pseudomonas nautica 617, which was isolated from superficial marine sediment, was found to require sodium for growth. Growth also appeared to be sensitive to the divalent cation, Mg2+, the presence of which, together with that of Na+, was necessary for achieving maximal growth. We investigated cell capacity to resist lysis after washing with either 0.05 M MgCl2 or 0.5 M NaCl, by monitoring suspension optical density changes as well as the release of ultraviolet absorbing material. Mg2+ turned out to play a significant role in stabilizing the structure of the cell envelope. Respiratory activity was also sensitive to ionic environment. With cells washed with 0.05 M MgCl2 and suspended in 0.05 M Tris buffer, the respiration rate, assessed by N2O evolution, was 15% of that measured in artificial sea water. Upon addition of 0.5 M Na+, nitrous oxide production rose to 32% of the reference level. The dinitrification rate was fully restored by further addition of 0.05 M Mg2+. K+ alone had almost no effect, but when added with Na+, the rate of denitrification increased to 45%.

Acute thrombosis of a vena cava filter with a clot above the filter. Successful treatment with low-dose urokinase.

Inferior vena cava thrombosis is a major complication after filter placement. The thrombus can propagate through the filter leading to a high risk of pulmonary embolism. We report such a case in a patient with a Günther filter, successfully treated with urokinase, and we discuss the efficacy and the safety of thrombolytic therapy in such situations.

Death of terminally ill patients on a stretcher in the emergency department: a French speciality?

OBJECTIVES: To determine the frequency, modalities of admission and management of terminally ill patients who died on a stretcher in an emergency department (ED). DESIGN AND SETTING: Retrospective study in an ED of a university hospital. METHODS: Current place of residence, modalities of admission in ED, mortality probability scores and type of management were extracted for each patient in the terminal stage of chronic disease who died on a stretcher in our ED during a 3year period. RESULTS: Of 159 deaths observed in the ED, 56 (35%) concerned terminally ill patients. The illness was a malignancy in 22 cases, a neurological disease in 22 cases and a cardiopulmonary disease in 12 cases. Most of the patients were referred by their regular doctor. Seventy-two percent of the malignancy patients were living at home, 55% of the neurological patients came from nursing facilities and 58% of the cardio-respiratory patients came from the hospital. In 73%, 83% and 23% of the patients with malignancy, cardiopulmonary and neurological diseases, respectively, admission was related to the evolution of the chronic disease. Severity of illness on admission was similar whatever the disease. Request for compassionate end-of-life care was expressed in only 12.5%. At the ED, 91% of patients with neurological diseases received palliative support care. Supportive therapy was undertaken in one third of patients with malignancy or cardiopulmonary disease. CONCLUSION: An ED may be used as a place for dying for some terminally ill patients. This could be related to the legal opposition to withdrawal or withholding of life-support therapies as well as the absence of guidelines from scientific bodies.

Endotoxaemia in patients with severe sepsis or septic shock.

OBJECTIVE: To examine the incidence and the bacteriological and clinical significance of endotoxaemia in ICU patients with severe sepsis or septic shock. DESIGN: Prospective review. SETTING: A 15-bed general ICU in a university hospital. PATIENTS: One hundred sixteen patients hospitalised in our ICU fulfilling Bone's criteria for severe sepsis or septic shock and with an available early endotoxin assay (chromogenic limulus assay). INTERVENTIONS: None. MEASUREMENTS AND RESULTS: The clinical characteristics of the population were: age 63.6 +/- 11.4 years; SAPS II: 45.4 +/- 15.6; mechanical ventilation: 72.4%; septic shock: 51.7% (n = 60); bacteraemia: 28.4% (n = 33); gram-negative bacteria (GNB) infection 47.4% (n = 55); ICU mortality: 39.6% (n = 46). Detectable endotoxin occurred in 61 patients (51.2%; mean level: 310 +/- 810 pg/ml). There was no relationship between detectable endotoxin and severity of infection at the moment of the assay. Endotoxaemia was associated with a higher incidence of bacteraemia (39.3% vs 16.3%; p = 0.01). There was a trend (p = 0.09) towards an association between positive endotoxin and gram-negative bacteraemia or GNB infection but this was non-significant. This relationship became significant only in the case of bacteraemia associated with GNB infection irrespective of the site of infection. CONCLUSION: Early detection of endotoxaemia appeared to be associated with GNB infection only in cases of bacteraemic GNB infection. Early endotoxaemia correlated neither to occurrence of organ dysfunction nor mortality in patients with severe sepsis or septic shock. This study suggests that the use of endotoxaemia as a diagnostic or a prognostic marker in daily practice remains difficult.

The oxygenation variations related to prone positioning during mechanical ventilation: a clinical comparison between ARDS and non-ARDS hypoxemic patients.

OBJECTIVES: To compare, in clinical practice, the oxygenation variations related to prone positioning (PP) during mechanical ventilation in ARDS and non-ARDS hypoxemic patients. DESIGN AND SETTING: Prospective observational study of data on consecutive patients treated with the same protocol in the intensive care unit (ICU) of a university hospital. PATIENTS: From May 1996 to December 1998, 226 PP periods without adjunction of nitric oxide (NO) inhalation and/or almitrine bismesylate infusion, performed in 59 mechanically ventilated hypoxemic patients (arterial oxygen tension/fractional inspired oxygen (PaO2/FIO2) ratio <300 mmHg) with no evidence of left ventricular failure, were included in this study. MEASUREMENTS: Arterial blood gas was measured before the PP, at 1 h from the beginning of the PP, at the end of the PP and 1 h after returning to the supine position. RESULTS: We analyzed 136 PP periods in 34 non-ARDS patients (60.2%) and 90 in 25 ARDS patients. The PP was repeated and the duration of the PP periods was: 10.6+/-0.22 h. The PP during the mechanical ventilation appeared to be safe and well tolerated. A PaO2/FIO2 ratio improvement at the end of the PP period, occurred for 196 periods (86.7%) with a mean PaO2/FIO2 ratio increase of +46.4+/-0.03% at the end of the PP periods compared to the baseline supine value. The PaO2/FIO2 ratio variations at 1 h after the start of the PP, at the end of the PP period and at 1 h after the return to supine were not different in ARDS or non-ARDS hypoxemic patients. The PaO2/FIO2 ratio improvement appeared to be more intense and more rapid in ARDS patients. CONCLUSIONS: In about 90% of periods, PP improved the PaO2/FIO2 ratio in patients with ARDS as well as in hypoxemic patients with non-ARDS. Studies are necessary to determine the impact of PP on survival and the mechanical ventilation duration in ARDS or non-ARDS hypoxemic patients.

Serum and ascitic procalcitonin levels in cirrhotic patients with spontaneous bacterial peritonitis: diagnostic value and relationship to pro-inflammatory cytokines.

OBJECTIVE: To assess the potential role of procalcitonin and pro-inflammatory cytokines, TNF-alpha, and IL-6, in the diagnosis of spontaneous bacterial peritonitis (SBP). DESIGN: Prospective study. SETTING: The emergency unit of a teaching hospital. PATIENTS: We included 21 patients with SBP and 40 patients with sterile ascitic fluid. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: For the diagnosis of SBP, the best markers were serum levels of procalcitonin with a cut-off value of 0.75 ng/ml, a sensitivity of 95%, a specificity of 98%, and ascitic fluid levels of IL-6 with a cut-off value of 5,000 ng/ml, a sensitivity of 100%, and a specificity of 88%. C-reactive protein and serum polymorphonuclear count have low sensitivity/specificity at 62/92% and 57/90%, respectively. From 21 patients with SBP, ascitic fluid to serum ratio of TNF-alpha and IL-6 was greater than to 2 in all cases with a mean at 6.2 +/- 6.5 and 34 +/- 31, respectively. By contrast, this ratio for procalcitonin was less than 1 in all cases with a mean at 0.31 +/- 0.25. We found no correlation between procalcitonin levels and cytokine levels in either ascitic fluid or serum. CONCLUSIONS: Serum procalcitonin level may become a useful marker for the diagnosis of SBP in cirrhotic patients. The low ratio of ascitic fluid to serum procalcitonin supports the hypothesis that procalcitonin is not produced intraperitoneally.

Prospective study of nosocomial colonization and infection due to Pseudomonas aeruginosa in mechanically ventilated patients.

OBJECTIVE: To investigate the respective contribution of endogenous and exogenous transmission of Pseudomonas aeruginosa in the colonization of lungs in the mechanically ventilated patient, to estimate the role of P. aeruginosa colonization in the occurrence of severe infections, and to extrapolate appropriate control measures for the prevention of P. aeruginosa ventilator-associated pneumonia. DESIGN: Prospective study of the presence of P. aeruginosa (in stomach fluid, throat specimens, stool, and sputum) on admission, twice a week throughout the patient's stay, and in their environment. O-serotyping, pulsed-field gel electrophoresis, and arbitrarily-primed polymerase chain reaction were used to characterize the strains. SETTING: The two intensive care units (ICUs 1 and 2) of a university hospital. PATIENTS: During a 6-month period, 59 patients were included (21 in ICU 1 and 38 in ICU 2). RESULTS: P. aeruginosa was isolated in 26 patients, including ten pneumonia cases and seven colonizations on admission. The incidence of acquired colonization was statistically different between the two ICUs: 5.5 and 20.5 per 1000 days of mechanical ventilation, in ICUs 1 and 2, respectively. Endogenous acquisition was the main origin of P. aeruginosa colonization (21 of 26 patients) and the upper respiratory tract was the main bacterial reservoir in broncho-pulmonary colonization and infection. However, during the 6-month period of the study, a multidrug-resistant strain of P. aeruginosa O:11, isolated in the sink of the room of 12 patients, was found responsible for two colonizations (1 digestive, 1 throat/lungs) and one pneumonia. As a whole, from 26 cases of colonization/infection with P. aeruginosa, 5 were related to an exogenous contamination (environmental reservoir in 4 patients and cross-contamination in one patient). CONCLUSIONS: These results emphasize the need for applying various infection control measures to prevent colonization of patients with P. aeruginosa, including strategies to limit the potential of sinks from acting as a source or reservoir for this bacterium.

Adjvant treatment of tongue and floor of the mouth cancers.

Since January 1974, 95 patients with anterior tongue and floor of the mouth cancers were included in a randomized trial. After stratification according to staging and initial treatment, one-third of the patients received chemotherapy for 2 years (methotrexate 400 mg followed by citrovorum factor 100 mg + bleomycin 60 mg/week, during the first 15 weeks), one-third of the patients received immunotherapy with weekly C. parvum injections during 2 years, while the remaining third did not receive any treatment. If adjuvant treatment seems to delay recurrence it did not significantly decrease the recurrence rate. Survival is also not signigicantly modified by adjuvant treatment and was better for patients with small tumors. Patients who previously received radiotherapy did not benefit from adjuvant therapy.

Effects of long travels in sitting position in elderly volunteers on biological markers of coagulation activation and fibrinolysis.

OBJECTIVE: To evaluate whether long travel in sitting position is associated with an increase of coagulation activation and/or a decrease of fibrinolytic activity. DESIGN: Comparison of blood coagulation and fibrinolysis parameters before and after two pleasure trips by bus organized in winter period (600 km in 8 hours) and in summer period (1200 km in 16 hours). SUBJECTS: 31 and 23 healthy elder volunteers for the winter and the summer trip respectively. Nine other elder volunteers were selected as a control group for the winter study. MAIN OUTCOME MEASURES: prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin III (TAT), D-dimers (D-D), factor VII activated, plasminogen activator inhibitor (PAI), tissue-type plasminogen activator (t-PA), plasma albumin. RESULTS: A significant difference before and after the travel was only observed for TAT in the summer period. However all values of TAT were in the normal range. No volunteer presented with thromboembolic disease during the month following the travel. CONCLUSION: In the condition of our study, long travel in sitting position does not lead to an enhanced procoagulant state for elderly with varicose veins. These results suggest that there is no biological support to propose heparin prophylactic therapy for the elderly with varicose veins wishing to travel by bus.

Thrombotic thrombocytopenic purpura: MR findings.

Neurologic manifestations occur in over 90% of patients with thrombotic thrombocytopenic purpura. Neuropathologically, thrombi produce occlusion of terminal arterioles and capillaries resulting in diffuse small infarcts. In the great majority of surviving patients, brain CT does not disclose any abnormalities. The authors report a case of thrombotic thrombocytopenic purpura in which brain MR examination showed multiple punctate lesions in the white matter.