Theoretical considerations regarding the thione-thiol tautomerism in 2-(5-mercapto-1,3,4-thiadiazol-2-ylthio)acetic acid.

The acidity constants Ka1 and Ka2 of 2-(5-mercapto-1,3,4-thiadiazol-2-ylthio)acetic acid have been determined both by experimental and theoretical methods. pKa computations at B3LYP/6-311+G(d,p) level of theory were carried out for the two tautomeric forms, thiol and thione, of the above-mentioned acid. Comparisons between the experimental and theoretical values led to the establishing of the most stable tautomer of 2-(5-mercapto-1,3,4-thiadiazol-2-ylthio)acetic acid in aqueous solution. Also, a DFT study regarding the reactivity, aromaticity and population analysis of the two tautomers has been performed.

Expanding the product portfolio of carbon dioxide and hydrogen-based gas fermentation with an evolved strain of Clostridium carboxidivorans.

CO2:H2-based gas fermentation with acetogenic Clostridium species are at an early stage of development. This work exploited the Adaptive Laboratory Evolution technique to improve the growth of C. carboxidivorans P7 on CO2 and H2. An adapted strain with decreased growth lag phase and improved biomass production was obtained. Genomic analysis revealed a conserved frameshift mutation in the catalytic subunit of the hexameric hydrogenase gene. The resulted truncated protein variant, most likely lacking its functionality, suggests that other hydrogenases might be more efficient for H2-based growth of this strain. Furthermore, the adapted strain generated hexanol as primary fermentation product. For the first time, hexanol was produced directly from CO2:H2 blend, achieving the highest maximum productivity reported so far via gas fermentation. Traces of valerate, pentanol, eptanol and octanol were observed in the fermentation broth. The adapted strain shows promising to enrich the product spectrum targetable by future gas fermentation processes.

Numerical study of the effect of channel aspect ratio on particle focusing in acoustophoretic devices.

Acoustophoretic microfluidic devices are promising non-contact and high-throughput tools for particle manipulation. Although the effectiveness of this technique has been widely demonstrated for applications based on micrometer-sized particles, the manipulation and focusing of sub-micrometer ones is challenging due to the presence of acoustic streaming. In this article, our study has the aim to investigate and understand which geometrical parameters could be changed to limit the acoustic streaming effect. We numerically study the well-known rectangular cross section of a microfluidic channel and perform a parametric study of the aspect ratio for several particle sizes. The efficiency of the focusing, is explored for different sized particles in order to identify a trend for which the acoustic streaming does not drastically influence the focusing motion of the particles. The possibility to efficiently separate different solid components in liquid suspensions, i.e. the whole blood, is crucial for all applications that require a purified medium such as plasmapheresis or an increase of the concentration of specific subpopulation as the outcome, such as proteomics, cancer biomarker detections and extracellular vesicles separation.

Power M-Mode Doppler and single-gate spectral analysis using a 2-MHz pulsed-wave Doppler transducer to directly detect cervical internal carotid artery stenosis: use of the continuity principle: report of a novel technique.

BACKGROUND AND PURPOSE: We hypothesized that direct cervical investigation with Power M-Mode Doppler (PMD) combined with single-gate Doppler spectral analysis (SGDSA) using a 2-MHz pulsed-wave Doppler transducer would show reasonable accuracy parameters when compared with standard color-coded carotid duplex ultrasound (CDU). METHODS: We prospectively screened for cervical internal carotid artery (ICA) stenosis by direct observation using a 2 MHz PMD/SGDSA device. PMD identified the artery (location, depth, flow direction) and SGDSA assessed waveform; peak systolic, end diastolic, and mean flow velocities (MFV) of the common carotid artery; cervical ICA proximally and distally; and external carotid artery. Diagnostic accuracy was compared with concurrent carotid duplex ultrasound. The continuity principle was applied using the proximal/distal cervical ICA MFV ratio. RESULTS: We examined 456 vessels (228 patients). Using ICA proximally/ICA distally MFV ratio of 1.5 or greater or absence of ICA signature, for 40% to 59% or greater stenosis (including occlusions), sensitivity was 75.4%, specificity 99.8%, positive predictive value 97.7%, negative predictive value 96.6%, and accuracy 96.7%. For MFV ratio 1.6 or greater or absence of ICA signature and 60% to 79% or greater stenosis (including occlusions), sensitivity was 92.3%, specificity 98.1%, positive predictive value 81.8%, negative predictive value 99.3%, and accuracy 97.6%. CONCLUSIONS: Use of combined PMD and SGDSA to directly observe the extracranial ICA is reasonably accurate compared with carotid duplex ultrasound. Using the MFV ratio of proximal/distal extracranial ICA improves accuracy parameters and provides a quick and effective bedside screen for ICA stenosis. This novel technique should be considered part of the standard PMD/transcranial Doppler examination.

Phase II trial of fludarabine monophosphate as first-line treatment in patients with advanced follicular lymphoma: a multicenter study by the Groupe d'Etude des Lymphomes de l'Adulte.

PURPOSE: Fludarabine monophosphate (FAMP) is a major drug in the treatment of chronic lymphocytic leukemia and showed efficacy in selected groups of patients with low-grade lymphomas, most of them pretreated. The aim of this trial was to assess the efficacy and the toxicity of FAMP in untreated patients with follicular lymphoma. PATIENTS AND METHODS: Fifty-four untreated patients with advanced follicular lymphoma were treated with intravenous (i.v.) fludarabine at a dose of 25 mg/m2/d during 5 days every 4 weeks, to a maximum of nine cycles. RESULTS: The toxicity of the drug was mild, mainly granulocytic. Granulocytopenia > or = 3 (World Health Organization [WHO]) was observed during 48 of 328 cycles (14.6%) and in 22 of 53 (41%) patients assessable for toxicity. Fludarabine had to be stopped prematurely because of toxicity in nine patients: marrow toxicity in five, peripheral neuropathy in two, and interstitial pneumonitis and hepatitis in one patient each. Among 49 patients assessable for response, the overall response rate was 65% and the complete response (CR) rate 37%. The median progression-free survival interval for all patients was 13.6 months. CONCLUSION: These results confirm that fludarabine is active when used as first-line treatment in patients with follicular lymphoma and has a low toxicity rate. It may be used as single treatment in elderly patients. Associations of fludarabine with other drugs active against follicular lymphoma need to be determined.

Diagnostic value of image processing in myocardial scintigraphy.

The diagnostic value of stress myocardial analog scintigrams, and of five image-processing methods, was assessed by a decisional analysis in 96 patients undergoing coronary arteriography. The methods involved digitalization, nine-point binomial smoothing, background subtraction by linear interpolation, stationary filtering, and a combination of them. The difference between after-test probabilities of having the disease with a positive or a negative examination provided a discriminant index for different prevalences of the disease. Though the processing methods failed to improve the detection of a circumflex stenosis, the stationary filter significantly increased the diagnostic value for the detection of stenosis in a left anterior descending artery for a large range of prevalence, and in a right coronary artery at high prevalence. Thus, the filter seemed to provide a useful tool for enhancing the diagnostic value of myocardial scintigraphy.

Surgical management of acute dissections involving the ascending aorta. Early and late results in 38 patients.

Thirty-eight patients (32 men and six women, mean age 48.1 years) were operated upon for acute dissection involving the ascending aorta. The surgical procedure included multiple peripheral arterial cannulations, resection of the initial intimal tear if found (35 cases), and obliteration of the false channel by double cuffing with Teflon of the two layers of the dissecting process proximally and distally. When present (29 cases), aortic regurgitation was usually (21 cases) managed by conservative remodeling of the aortic anulus; 34 prosthetic replacements of the ascending aorta and four replacements of the arch were achieved. The operative mortality was 7.9% (3138) and the overall hospital mortality was 23.7% (9138). Nonfatal complications occurred in 11 patients (29%). There were three late deaths (10.3%). Mean follow-up was 3.4 years (2 months to 8 years, 8 months). Twenty-three (88.5%) of the 26 patients were asymptomatic. Contrast tomodensitometry was performed in 14 patients; in type II (two patients), the aorta was normal; in type I (12 patients), residual abnormalities were noted: patency of the false channel (10 cases), aneurysmal dilatation (seven cases), and reduction of the true lumen by the false channel (four cases). These results emphasize the need for scrupulous long-term follow-up in surgically treated aortic dissections.

Evaluation of Doppler examination for diagnosis of catheter-related deep vein thrombosis.

The accuracy of Doppler examination was evaluated for the diagnosis of catheter-related venous thrombosis in 40 postoperative patients. Deep vein thrombosis was detected by venography in 15 patients and confirmed by the Doppler technique in a double blind study. Only one false-positive and one false-negative result were obtained with the Doppler technique. This technique appears to be valuable for the early diagnosis of catheter-related vein thrombosis, even in asymptomatic patients.

Intrapleural administration of streptokinase in complicated purulent pleural effusion: a CT-guided strategy.

OBJECTIVE: To determine the usefulness and the results of a strategy using intrapleural streptokinase (SK) instillation guided by repeated computed tomography (CT) scan examinations in pleural empyemas unresponsive to chest tube drainage. DESIGN: A retrospective chart review. SETTING: The medical Intensive Care Unit and Department of Radiology, in a university hospital. PATIENTS: Sixteen patients with empyema who had a persistent pleural effusion despite drainage, among 37 patients with infectious pleural effusion. INTERVENTIONS: In the 16 patients, CT examination was performed before and at least once after SK. Intrapleural SK was instilled, either through the chest tube or via a needle puncture, according to the CT scan results. RESULTS: The first CT scan confirmed a persistent effusion in all, showing a multiloculated effusion in 13 patients, and an ectopic loculus in one. The first SK instillation resulted in a dramatic increase of fluid drained per day (from 68 +/- 28 ml to 567 +/- 262 ml; p < 0.001), leading to complete resolution in 11 patients, while the others required a second CT scan-guided procedure. In one, the chest tube was misplaced, while in two, transparietal injection was needed. Finally, a complete resolution was observed in 14 (87.5%) of the patients. Two patients had a poor initial response to SK and were eventually scheduled for video-thoracoscopy. A single episode of chills and fever was observed among 32 SK instillations. CONCLUSION: CT-guided SK instillation in pleural empyema appears to be safe, and allowed complete resolution in 87.5% of our patients.

Computed tomography and post-laparotomy intra-abdominal abscesses.

Thirty-one patients were prospectively studied and had abdominal computed tomography for post laparotomy sepsis. Computed tomography is of particular interest in seriously ill post-operative patients, 15 of our patients were on ventilators, and it enabled diagnosis and localization of abscesses in 15 patients. Drainage could therefore be achieved via a limited surgical approach, and extensive laparotomy was avoided. Of 16 patients without abscess, the abdominal computed tomogram was negative in 14 cases and there were two false positives. The overall accuracy was 0.94 with a sensitivity of 1 and a specificity of 0.88. The ability to screen the whole abdomen and exactly localize the lesion are the advantages of this non-invasive method.

Clinical and biological analysis of peripheral T-cell lymphomas: a single institution study.

Peripheral T-cell lymphoma (PTCL) accounts for 15-20% of non-Hodgkin's lymphoma in the Western World. Clinical, histopathologic, phenotypic and genotypic data were received from 33 cases of PTCL referred to our institution. The median age order was 50 years, 78% were males, and 18% had a history of a preceding disorder of the lymphoid system. 60% had stage 4 at diagnosis and B symptoms were also present in 60%. The most frequent sites of extranodal involvement were bone marrow (54%), liver (45%) and skin (33%). Twenty-eight of 33 cases were histologically classified according to the Working Formulation (most in the diffuse mixed and large-cell subgroups) and the Kiel updated system. Phenotypic and genotypic studies of malignant cells showed a considerable heterogeneity with respect to the expression of either T-cell receptor (TCR) alpha beta and gamma delta and pan-T differentiation molecules. Of the studied cases 63% expressed TCR-alpha beta. All five patients with PTCL of the TCR-gamma delta subtype had a peculiar extra-nodal presentation. The vast majority of cases expressed an abnormal T-cell phenotype with respect to the expression of pan-T antigens, including the lack of expression of the TCR-associated CD3 molecule in 2 cases. Rearrangements of the TCR beta and/or delta-chain genes showed clonality in 21 of the 23 studied cases. Twenty-five patients were treated with a multiagent chemotherapy regimen with curative intent and the remainder received a less intensive palliative regimen. Only 9 patients achieved CR (8 of whom had received an anthracycline-containing regimen) and the 4-year survival rate was 25%.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous Fine Needle Aspiration Cytology and Biopsy in the Diagnosis and Classification of Lymphoma: Clinical Evaluation.

In some patients with suspected de novo or recurrent lymphoma, the absence of a palpable mass or peripheral lymph node enlargement can be a diagnostic challenge. We report our experience of fine needle aspiration (FNA) and biopsy in the management of 47 consecutive patients investigated in our institution over a period of 4 years. Lymphoma was suspected in 32 cases, and recurrent disease in 15 cases. Cytology was performed in all patients and biopsy in 16 patients, when a safe approach was possible. The specimens were obtained with computed tomography guidance and were diagnostic by cytology in 85% of cases: 28 patients had a newly diagnosed lymphoma and 3 had recurrent disease; residual fibrosis was diagnosed in 2 cases. Five patients with a previously diagnosed lymphoma had a new neoplasm: lung carcinoma: 3, renal adenocarcinoma: 1, metastatic lymph nodes: 1. One patient had non-neoplastic intercurrent disease (pulmonary nocardiosis). In 7 patients, no conclusive tissue was obtained (acellular: 1, blood: 3, necrosis: 3). In one case of suspected recurrent disease, a false-positive result was obtained. Cytology always allowed distinction between non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD), with attempts to subclassify NHL according to the International Working Formulation. In 12 patients, immunochemical studies could be performed for immunologic subclassification of lymphoma on the basis of cytology (n = 6) and biopsy (n = 6). Our results show that percutaneous fine needle aspiration cytology is a reliable method for the diagnosis and classification of lymphoma, and immunologic studies can be performed on cytology alone if biopsy is unsafe.

Pancreatic cystic neoplasms.

Cystic neoplasms are an uncommon group among pancreatic tumors. Because of advances in noninvasive diagnostic procedures, these lesions are more frequently detected and surgically treated. New pathological entities have been recently described with their own prognosis. 1. In a large number of cases, the imaging procedures can differentiate microcystic adenoma from mucinous cystadenoma, the more frequently encountered lesions. A well-defined mass with innumerable small cysts producing a honeycomb appearance with central stellate septae is suggestive of microcystic adenoma. A well-defined multilocular mass containing thin, straight or curvilinear septae with papillary projections and local thickening is suggestive of mucinous cystadenoma. 2. No sonographic or CT finding allows the differentiation between mucinous cystadenoma and cystadenocarcinoma, however; the imaging features depend on the grade of malignancy. 3. Thus, in the majority of cases of cystic lesions, fine needle aspiration with appropriate stains is recommended.

Intraarticular tolerability and kinetics of gadolinium tetra-azacyclododecane tetraacetic acid.

RATIONALE AND OBJECTIVES: We assessed the tolerability and the intraarticular kinetics of gadolinium tetra-azacyclododecane tetraacetic acid (Gd-DOTA) using magnetic resonance (MR) imaging. METHODS: Twelve of 18 dogs received an intraarticular injection of Gd-DOTA solution. Pathologic examination of all joints was performed with assessment of Gd-DOTA bone absorption. Effects of Gd-DOTA on chondrocyte viability and proliferation in vitro were determined using cultures of rabbit chondrocytes. Four dogs underwent MR imaging of the stifle joint before and after intraarticular injection of 0.8 ml Gd-DOTA at a concentration of 2 mmol/l (300 mOsm/l). Intraarticular kinetics of Gd-DOTA were determined from quantitative measurements using repeated sagittal spin-echo T1-weighted images. RESULTS: No microscopic changes of the joints or Gd-DOTA bone absorption were detected. No cytotoxicity for chondrocytes was observed at a concentration of 5 mmol/l, but a decreased cell count was observed at a high concentration (50 mmol/l). The intraarticular Gd-DOTA concentration decreased with time according to a logarithmic curve with an intraarticular half-life of 103-152 min (M = 127 min). CONCLUSION: Gd-DOTA is a safe intraarticular contrast agent with a long half-life in the joint cavity.

CT features of cardio-pericardial masses.

The results of dynamic computed tomography (CT) in 13 patients with intracardiac filling defects and one with a pericardial lipoma are presented. The intracardiac filling defects were due to thrombus in five cases, myxoma in three, hydatid cysts in three, haemangiopericytoma in one and sarcoma in one. These kinds of lesions are well identified by CT which seems to be superior to echocardiography in the characterisation of the components and in the evaluation of the malignant spreading masses.

Computed tomography diagnosis of an atheromatous aneurysm of a right aberrant subclavian artery.

A patient presented with an asymptomatic mass which was found to be an artheromatous aneurysm of an aberrant right subclavian artery. Diagnosis was made by computed tomography. It is proposed that CT be carried out before arteriography for the diagnosis of congenital abnormalities of the aortic arches and great vessels.

Acute swelling of the limbs: magnetic resonance pictorial review of fascial and muscle signal changes.

OBJECTIVE: This pictorial review analyzes the magnetic resonance (MR) fascial/muscular changes in 69 patients referred as emergencies with acute swelling of the limbs (ASL) from various causes. METHODS AND MATERIAL: A prospective MR imaging (MRI) study of 69 patients referred as emergencies for ASL was performed. Our population consisted of 45 patients with skin and soft-tissue infections (cellulitis and necrotizing fasciitis, and pyomyositis), six patients with soft-tissue inflammatory diseases (dermatomyositis, graft-versus-host disease), 11 patients with acute deep venous thrombosis, three patients with rhabdomyolysis, one patient with acute denervation and three other patients with rare diseases. Hematomas, tumorous or infectious bone involvement and soft-tissue tumors were excluded. All studies included spin echo T1-weighted images and spin echo T2-weighted images. Gadolinium-enhanced spin echo T1-weighted images were obtained when an abscess was suspected on T2-weighted images. Selective fat-saturated T1- and T2-weighted sequences were also used. MRI analysis was performed to obtain a compartmentalized anatomical approach according to the location of signal abnormalities in subcutaneous fat, superficial and deep fascia and muscle. RESULTS: In all patients with ASL, MRI demonstrated soft-tissue abnormalities involving subcutaneous fat, superficial fascia, deep fascia, or muscle. Although MR findings were non-specific, MRI appears sensitive for detecting subtle fascial and muscle signal changes. CONCLUSIONS: In skin and soft-tissue infections, MRI can be helpful for therapeutic management by determining the depth of soft-tissue involvement, particularly within fasciae and muscles, which is partly related to the severity of cellulitis with severe systemic manifestations. MRI can also aid the surgeon in diagnosing abscesses. In inflammatory diseases, MRI can determine the best site for biopsy and also monitor therapeutic response.

Intrahepatic calculi: imaging by MR.

The magnetic resonance (MR) examinations of six patients with intrahepatic calculi were reviewed retrospectively to 1) determine the ability of MR to demonstrate intrahepatic calculi and 2) assess the MR appearance of the stones. In five out of six cases, MRI demonstrated intrahepatic calculi. In three cases, stones exhibited a low intensity signal on the different spin echo (SE) sequences, as previously described by in vitro and in vivo studies. However in two other cases, a significant signal with short T1 and relatively long T2 relaxation times was noticed. These different features are discussed in relation to chemical and physical differences in intrahepatic calculi and compared with variable CT attenuation values of stones. MRI seems to provide complementary information concerning intrahepatic calculi.

Unusual complication of liver irradiation: acute thrombosis of a main hepatic vein: CT and MR imaging features.

The pathologic changes resulting from liver irradiation include congestion, fibrosis, and veno-occlusive disease. We report an unusual complication of radiation induced injury: acute thrombosis of a main hepatic vein within the radiation port. CT and MR features are described and the etiology of this unusual complication is discussed.

[Emergency aorto-coronary bypass. Indications and results in a homogenous series of 50 patients]. / Le pontage aorto-coronaire d'urgence. Indications et résultats dans une série homogène de 50 malades

Emergency myocardial vascularization through an aorta-to-coronary by-pass has been extended recently to acute evolutive accidents of coronary artery disease: either to its minor forms, as the menace syndrome, or its more severe forms, such as complicated myocardial infarction. This study aimed at a retrospective analysis of 50 patients, all operated upon as an emergency, by the same surgical team. The problems peculiar to any group of indications, and the practical and theoretical problems posed by extension of this type of emergency surgery were discussed.