Interiaboratory Evaluation of an Off-Line Supercritical Fluid Extraction/Infrared Spectrometric Method for Determination of Petroleum Hydrocarbons in Solid Matrixes

A collaborative study was conducted, with 14 laboratories participating, to determine the method accuracy and precision of the proposed U.S. Environmental Protection Agency Methods 3560 and 8440. These methods involve the extraction of petroleum hydrocarbons from solid matrixes with supercritical carbon dioxide at 340 atm and 80°C for 30 min (dynamic), collection of the extracted materials in tetrachloroethene (Method 3560), and analysis of the extracts by infrared (IR) spectrometry (Method 8440). The study design was based on the AOAC blind replicate design with balanced replicates. The study samples consisted of 4 solid matrixes that had petroleum hydrocarbon contents ranging from 614 to 32 600 mg/kg. Each of the 4 matrixes was extracted in triplicate, and the extracts were analyzed with 2 different IR spectrometers. In addition, each of the participating laboratories extracted a sample of unspiked clay soil, the same clay soil spiked with corn oil and reference oil at 1000 mg/kg each, and the same clay soil wetted to 30% water content and spiked with motor oil at 10 000 mg/kg (the latter 3 samples were extracted only once). Results indicated that the overall method accuracy for concentrations ranging from 614 to 32 600 mg/kg was 82.9%; the mean recoveries of petroleum hydrocarbons for each of the 4 solid matrixes ranged from 77.9 to 107% for analyses performed with the Perkin-Elmer Fourier transform IR spectrometer and from 75.9 to 101% for analyses performed with the Buck-Scientific IR spectrometer; the differences between the 2 instruments on a sample-bysample basis were less than 17% for the total petroleum hydrocarbon determinations. The interiaboratory method precisions (RSDR) appeared to be matrix-dependent and ranged from 17.3 to 45.4% for analyses performed with the Perkin- Elmer Fourier transform IR spectrometer and from 16.7 to 47.9% for the Buck-Scientific IR spectrometer. The intralaboratory method precisions (RSDr) appeared to be less matrix-dependent and ranged from 11.5 to 17.0% for analyses performed with the Perkin-Elmer FTIR spectrometer and from 11.1 to 18.2% for the Buck-Scientific IR spectrometer. Method accuracy and precision data are also presented for the 5 laboratories that used Isco supercritical fluid extraction systems and for the 7 laboratories that used vessels with volumes of 3.5 mL or less with different supercritical fluid extraction systems.

Efficacy and safety of tandem hemodialysis and immunoadsorption to desensitize kidney transplant candidates

OBJECTIVES

We conducted a desensitization program in our center in patients undergoing kidney transplant for end-stage renal disease. These patients had a living-donor either ABO incompatible and/or human-leukocyte antigen-incompatible. The safety and efficacy of this program were evaluated.

MATERIALS AND METHODS

A pretransplant desensitization program relies on immunosuppressants and apheresis to remove detrimental antibodies. We chose immunoadsorption as the apheresis technique, and coupled this with hemodialysis in a tandem procedure.

RESULTS

We report on the efficacy of this new method in 120 procedures performed in 20 patients (14 ABO incompatible, 6 ABO incompatible/human leukocyte antigen-incompatible). The tandem procedure was well tolerated, and saved time compared with conducting sequential immunoadsorption and hemodialysis (6 h vs 10 h). The tandem procedure was associated with significantly decreased isoagglutinin titers and donor-specific alloantibodies (assessed by mean fluorescence intensity). Dialysance was effective (183, 102-264). The biochemical and hematologic parameters were similar to those observed after a conventional hemodialysis session, with the exception of protidemia; this might be related to some degree of albumin loss during the immunoadsoprtion procedure. The posttransplant events included 1) one ABO incompatible / human leukocyte antigenincompatible patient with vein thrombosis and ultimate kidney loss; 2) two patients with steroidsensitive cellular acute rejection; and 3) two patients with acute antibody-mediated rejection, which was successfully treated with apheresis and steroid pulses, plus rituximab in one and eculizumab in the other.

CONCLUSIONS

We conclude that the tandem immunoadsorption-hemodialysis procedure is efficient at desensitizing patients with end-stage renal disease who are candidates for a living ABO incompatible and/or human leukocyte antigenincompatible donor-kidney transplant.

Gas-Temperature Imaging in a Microwave-Plasma Nanoparticle-Synthesis Reactor Using Multi-Line NO-LIF Thermometry

Multi-line NO-LIF thermometry is used to determine the two-dimensional temperature distribution inside a low-pressure plasma reactor. The applicability of multi-line temperature measurements to non-equilibrium plasma environments was evaluated. Temperatures between 300 and 3000 K have been observed, while microwave power, and pressure show a strong effect on the temperature distribution. Metal-organic precursors added for particle synthesis additionally influence the temperature through the heat release during particle formation and the oxidation of organic ligands.

Investigation of the accumulation of aromatic compounds during biogas production from kitchen waste

This paper presents laboratory scale studies on the anaerobic degradation of kitchen waste, with a high protein and fat content, using a quasi-continuous co-digestion process. The increased accumulation of non-degraded intermediates as an indication of process imbalances was examined in experiments where the substrate load was gradually increased. In addition to the critical rise of known toxic metabolites like ammonia, hydrogen sulphide or volatile fatty acids, aromatic acids accumulated with increasing substrate loading. These metabolites could be identified as intermediates from the anaerobe degradation of the aromatic amino acids phenylalanine, tyrosine and tryptophan. In most experiments the important finding was the early detection of aromatics, especially phenylacetic acid, even before the monitoring of volatile fatty acid concentrations gave an indication of a process imbalance. This demonstrates the potential use aromatic acids as indicators for an upcoming process failure.

Liquid chromatographic–mass spectrometric—analyses of anaerobe protein degradation products

A liquid chromatography-electrospray ionisation-mass spectrometry (LC-ESI-MS) method and a liquid chromatography-atmospheric pressure chemical ionisation-mass spectrometry (LC-APCI-MS) method was developed to identify metabolites from the anaerobe protein degradation to biogas. As consequence of a process failure the biogas production breaks down with increasing substrate loading, whereas different metabolites accumulate in the fermentation media. These compounds were identified as metabolites from the anaerobe degradation of the aromatic amino acids phenylalanine, tyrosine and tryptophan and accumulate in concentrations up to 300 mg/L when casein was used as model substrate.

Persistent spectral-hole burning in the wide-gap semiconductor SiC doped with vanadium

Persistent spectral-hole burning was performed in the gamma line of V(4+) in the wide-gap semiconductor 6HSiC. Spectral holes burned at 11 K were stable to temperatures of at least 320 K for several days. The hole-burning mechanism consists of two-step photoionization of V(4+) (self-gated spectral-hole burning). The spectral holes could be erased optically, either by pumping of electrons back from stable traps or, presumably, by a charge-transfer transition from the valence band to the V(5+) ions.

Variants within the 5'-flanking region and the intron I of the bovine growth hormone gene

In order to identify DNA variants potentially involved in the regulation of the expression of the bovine growth hormone gene, the 5'-flanking, the 5'-untranslated and the signal peptide coding regions of 15 cows (four German Friesian, two German Simmental, two Jersey, two Galloway, two Scottish Highland, two Charolais and one Ceylon Dwarf Zebu) were analysed. For each animal a region of about 1.2 kb was amplified by polymerase chain reaction (PCR) and sequenced. Six sites of variable nucleotides were identified in the 5'-flanking region of the gene and one in the intron I. Some of these variable sites are also potential binding sites for trans-acting factors (CAAT/enhancer binding protein (C/EBP), polyoma virus enhancer A binding protein 3 (PEA3), thyroid hormone response element (TRE)) and therefore possibly involved in the expression of the growth hormone gene. PCR amplification of specific alleles (PASA) tests for two of the sites (G2, G3) were established and the genotypes for these variants were analysed in 190 cows. The frequencies of the C alleles of the sites G2 and G3 were 0.63 and 0.76, respectively.

Association of generalized joint hypermobility with history, signs, and symptoms of temporomandibular joint dysfunction in children

This study determined the prevalence of signs and symptoms of temporomandibular joint dysfunction (TMD) in children with and without generalized joint hypermobility (GJH). Twenty children with GJH, ages 4-19, and 20 age- and sex-matched control children completed a TMD signs/symptoms history and underwent an examination consisting of palpation of the joints and associated musculature for tenderness, clicking, or crepitation. Children with historical or clinical findings were designated positive for TMD signs/symptoms. Maximum vertical opening, expressed as a percentage of lower facial height, and maximum mandibular lateral excursion (in mm) were recorded. Fifteen (75%) of the GJH participants and ten (50%) of the controls were positive for TMD findings. There were statistically significant differences between the groups for the presence of total positive findings (P < 0.001) and for responses to palpation of muscle or joint (P = 0.03). There were no significant differences in positive responses to the history alone, joint palpation alone, or muscle palpation alone. There were no significant differences between the groups in jaw excursions. This study suggests that children with GJH may be more likely to demonstrate some signs and symptoms of TMD than children with normal joint mobility.

Surface sensibility of the floor of the mouth and tongue in healthy controls and in radiated patients

Increased areas of anesthesia in the oral cavity have been shown to significantly impair oral function in normal individuals. In patients who undergo oral cavity reconstruction, loss of sensation plays a major role in producing disturbances in postoperative oral function. Free tissue transfer techniques have permitted the problem of sensory loss to be addressed through the use of sensate cutaneous free flaps, in which microneural anastomoses are performed between a sensory nerve supplying the flap and a recipient nerve in the head and neck. To critically assess the results of such reconstructions, the effect of sensory restoration on oral cavity rehabilitation must be studied. As a first step toward this goal, normal values for sensory discrimination of the floor of mouth and tongue are needed. Previous studies of oral sensation failed to examine the ventral tongue and floor of mouth. The purpose of this study is to determine the surface sensibility of these regions in healthy patients and in patients who received radiation therapy to the oral cavity. Sensation was evaluated using static and moving two-point discrimination in 90 healthy subjects divided equally into three age groups: 20 to 40 years, 41 to 60 years, and 61 to 80 years. In addition, 20 patients who received radiation therapy were studied. The mucosa of the dorsal and ventral aspects of the lateral tongue, tongue tip, and floor of mouth was examined. The tongue tip is the most sensitive area, followed by the dorsal lateral tongue, ventral lateral tongue, and floor of mouth. The effects of age and radiation therapy on sensory discrimination are discussed.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical decision-making in the treatment of pancreatic pseudocysts. Internal versus external drainage

One hundred patients with documented pancreatic pseudocysts who underwent surgical drainage are reported on. Accurate assessment of the size and location of the pseudocyst using ultrasonography, endoscopic retrograde cholangiopancreatography, angiography, and upper gastrointestinal roentgenography is essential. After diagnosis, the next 4 to 7 weeks is a critical period, after which surgical intervention becomes mandatory if the cyst has not resolved. This period between diagnosis and operation is hazardous and demands close clinical follow-up. When oepration is required, the preferred procedure continues to be internal drainage because it is associated with less morbidity and a lower mortality. However, external drainage appears to be a suitable second choice. Fewer than 10 per cent of the patients in this series who underwent external drainage developed fistulas, and the overall rate of late morbidity was acceptable.

Villous adenomas of the duodenum

A patient with multiple villous adenomas of the duodenum is described. Endoscopy plays an essential role in the management of these neoplasms. If no evidence of invasive malignancy is found on multiple endoscopic biopsies, wide local excision is the initial procedure of choice. Invasive malignancy found in either the endoscopic biopsy or the surgical specimen is indication for pancreaticoduodenectomy.