The matrix-assisted pulsed laser evaporation (MAPLE) technique has been successfully used to deposit highly uniform thin films of various functional materials such as non-linear optical (NLO) organic ...materials, conductive polymers, luminescent organic molecules and several types of proteinaceous compounds. MAPLE is a laser evaporation technique for growing thin films of organic and polymeric materials which involves directing a pulsed laser beam
(λ=193
nm;
fluence=0.01–0.5
J
cm
−2)
onto a frozen target (−40 to −160
°C) consisting of a solute polymeric or organic compound dissolved in a solvent matrix. Using MAPLE, thin films of
N-(4-nitrophenyl)-(
l)-prolinol or NPP, an NLO material; polypyrrole, a conductive polymer; and tris-(8-hydroxyquinoline) aluminum or Alq3, a luminescent organic compound, have been separately deposited with minor (in the case of Alq3) or no degradation (for the NPP and polypyrrole) to their optical and electrical properties. The MAPLE process has also been used to deposit discrete thin film micro-arrays of biotinylated bovine serum albumin (BSA). The deposited BSA films, after washing with a blocking protein and fluorescently tagged streptavidin, fluoresce when exposed to UV. This fluorescence indicates that the biochemical specificity of the transferred biotinylated protein is unaffected by the MAPLE process. These results demonstrate that the MAPLE technique can be used for growing thin films of functional polymer and active biomaterials.
Thin films of polyethylene glycol (PEG) of average molecular weight, 1400 amu, were deposited by both matrix-assisted pulsed laser evaporation (MAPLE) and pulsed laser deposition (PLD). The ...deposition was carried out in vacuum (~10 Torr) with an ArF (*l=193 nm) laser at a fluence between 150 and 300 mJ/cm. Films were deposited on NaCl plates, Si(111) wafers, and glass slides. The physiochemical properties of the films are compared via Fourier transform infrared spectroscopy (FTIR), electrospray ionization (ESI) mass spectrometry, and matrix-assisted laser desorption and ionization (MALDI) time-of-flight mass spectrometry. The results show that the MAPLE films nearly identically resemble the starting material, whereas the PLD films do not. These results are discussed within the context of biomedical applications such as drug delivery coatings and in vivo applications where there is a need for transfer of polymeric coatings of PEG without significant chemical modification.
Non-alcohol-induced steatohepatitis (NASH) is characterized by elevated serum aminotransferase activities with hepatic steatosis, inflammation, and occasionally fibrosis that may progress to ...cirrhosis. No established treatment exists for this potentially serious disorder. Our aim was to conduct a pilot study to evaluate the safety and estimate the efficacy of ursodeoxycholic acid (UDCA) and clofibrate in the treatment of NASH. Forty patients were diagnosed with NASH based on a compatible liver biopsy with other causes of liver disease, including alcohol abuse, excluded by history, serum tests, and use of ultrasound. Twenty-four patients received 13 to 15 mg/kg/d of UDCA for 12 months. Sixteen patients with hypertriglyceridemia were placed on clofibrate, 2 g/day for 12 months. Twenty-five women and 15 men entered the study. Six of 40 patients (15%) withdrew because of side effects. Four additional patients were withdrawn because of noncompliance; one of them later required liver transplantation. In the UDCA group, the decreases in mean serum levels of alkaline phosphatase, alanine transaminase (ALT), and gamma-glutamyl transpeptidase (GGT) as well as histological grade of steatosis were significant. Among the patients treated with clofibrate, no change from baseline was found in mean ALT, aspartate transaminase (AST), GGT, bilirubin, triglycerides, and cholesterol, or in histological grade of steatosis, inflammation, or fibrosis after 12 months of treatment as compared with entry. Alkaline phosphatase activities decreased significantly from baseline. Despite the known lipid-lowering effects of clofibrate, it did not appear to be of clinical benefit in the treatment of NASH in this 1-year pilot study. However, treatment of NASH with UDCA for 12 months resulted in significant improvement in alkaline phosphatase, ALT, GGT, and hepatic steatosis. The possible benefit of UDCA therapy should be further investigated in the context of a randomized, controlled trial. (Hepatology 1996 Jun;23(6):1464-7)
The Mid-Atlantic Ridge (MAR) is a topographically complex feature in the North Atlantic Ocean with little exploration of benthic fauna except in association with hydrothermal venting, resulting in ...the biodiversity and ecosystem functioning of the MAR benthos away from these sites remaining largely unknown. Stable isotope analysis of carbon, nitrogen and sulphur were undertaken on fauna collected north and south of the Charlie-Gibbs Fracture Zone, in areas believed to be devoid of hydrothermal venting, to investigate the trophodynamics of the benthic assemblage. δ13C and δ34S values of the benthic and bentho-pelagic fauna indicated a dependence on photosynthetic primary production, with no influence from an unknown chemosynthetic source. A large trophic discrimination in δ13C between consumers and potential food sources (particulate organic matter and surficial sediments) suggested reworking of organic carbon before assimilation by benthic fauna. Interpretation of sediment δ15N values was difficult as these ranged between −0.74 and 23.14‰, suggesting further work is required to understand nitrogen utilisation by benthic deposit feeders. Differences in trophic guilds (predators, predator–scavenger, surface deposit feeders, subsurface deposit feeders and suspension feeders) were evident for δ13C and δ15N, with the main difference between the mobile predators–scavengers and the benthic deposit feeders. Dividing the assemblage based on trophic guilds into food chains dependent on phytodetritus (deposit and suspension feeders) and predation–scavenging (fishes and crustaceans) resulted in strong positive correlations between δ15N and δ13C at both stations. These reflected the 2 dominant trophic pathways organic matter passed through deposit feeders and predatory and scavenging deep-sea fishes and crustaceans.
This document presents the official recommendations of the American Gastroenterological Association (AGA) on the evaluation and management of occult and obscure gastrointestinal bleeding. It was ...approved by the Clinical Practice and Practice Economics Committee on May 16, 1999, and by the AGA governing board on July 18, 1999.
GASTROENTEROLOGY 2000;118:197-200
The role of liver biopsy in the management of patients with nonspecific chronic liver enzyme abnormalities is not well established. The aim of this study is to determine whether liver histology ...changes the clinical impression formed before liver biopsy and the preliminary management plan.
Consenting asymptomatic adult patients with persistent (> or = 6 months) liver test abnormalities were enrolled. Patients with a strong suspicion for a specific liver disease were excluded. A presumptive diagnosis and a preliminary management plan were documented before a liver biopsy. After the liver biopsy, the patients were reassessed to determine the effect of the biopsy on the diagnosis and management plan.
A total of 36 patients were enrolled: 15 men and 21 women, with a median age of 51 yr. The prebiopsy diagnoses were nonalcoholic steatohepatitis (24), autoimmune hepatitis (3), primary biliary cirrhosis (2), primary sclerosing cholangitis (2), and miscellaneous (5 patients). The liver biopsy changed the diagnosis in 14% of cases. Lifestyle recommendations were not significantly altered by the biopsy. The liver biopsy affected the frequency of liver test monitoring in 13 patients (36%). Treatment recommendations were affected in 12 cases, 10 of whom were offered investigational therapy.
Although a liver biopsy may help to definitively establish the final diagnosis in patients, the results alter the presumptive prebiopsy diagnosis infrequently, and no proven therapy exists for the vast majority of these patients. Therefore, the risks and benefits of a liver biopsy should be carefully weighed, especially in settings in which investigational therapies are unavailable.
Aim Glucose transporter 1 deficiency syndrome (GLUT1‐DS) is an important condition for the general paediatrician’s differential armamentarium. We describe a case series of eight patients in order to ...raise awareness of this treatable neurometabolic condition. The diagnosis of GLUT1‐DS is suggested by a decreased absolute cerebrospinal fluid (CSF) glucose value (<2.2 mmol/L) or lowered CSF: plasma glucose ratio (<0.4).
Methods This is a review of eight Queensland patients with GLUT1‐DS. The clinical presentation, clinical course, laboratory investigations and treatment outcomes are discussed.
Results The clinical features noted in our patient cohort include combinations of ataxia, developmental delay and a severe seizure disorder that is refractory to anticonvulsant medications. Seizures are the most common clinical manifestation and may be exacerbated by phenobarbitone. The paired CSF: plasma glucose results ranged from 0.2 to 0.39 (normal <0.6) with an average of 0.33. 3‐O‐Methyl‐D‐Glucose uptake and GLUT1 Genotyping analysis have been performed on five patients thus far. Rapid and impressive seizure control was observed in 100% of our patients once the ketogenic diet was instituted, with half of the cohort being able to wean completely from anticonvulsants.
Conclusion Children presenting with a clinical phenotype consisting of a refractory seizure disorder, ataxia and developmental delay should prompt the consideration of Glucose transporter 1 deficiency syndrome. While the diagnostic test of lumbar puncture is an invasive manoeuvre, the diagnosis provides a viable treatment option, the ketogenic diet. GLUT1‐DS displays clinical heterogeneity, but the value of early diagnosis and treatment is demonstrated by our patient cohort.
Nine thousand two hundred twelve liver biopsies were performed according to a defined protocol, and data were prospectively recorded to identify risk factors for major bleeding. There were 10 fatal ...and 22 nonfatal hemorrhages (0.11% and 0.24%, respectively). By comparison with a control group that did not hemorrhage, malignancy, age, sex, and the number of passes were the only predictable risk factors. The risk of fatal hemorrhage in patients with malignancy is estimated to be 0.4%; for nonfatal hemorrhage, 0.57%. In patients undergoing liver biopsy for nonmalignant disease, the risks are 0.04% and 0.16%, respectively.
To define the validity of fecal blood as a marker for colorectal neoplasia in the screening setting and to compare yields by Hemoccult and HemoQuant fecal occult blood screening tests.
A multicenter ...masked comparison of fecal blood test results against structural colorectal evaluations and longitudinal follow-up, serving as criterion standards, in nonreferred subjects at risk for colorectal neoplasia.
Communities, primary care centers, referral centers.
Two groups: (1) 1217 patients aged at least 18 years undergoing routine structural surveillance evaluations following curative resection of a colorectal tumor and (2) 12312 relatives of colorectal cancer patients aged at least 50 years.
Blinded Hemoccult II and HemoQuant testing on three mailed-in stool samples per subject.
Sensitivity of fecal blood tests for colorectal neoplasia.
In the postresection group, surveillance evaluations revealed 46 malignant colorectal neoplasms and 402 polyps. At matched specificity, sensitivity of either test for cancer was 26% (95% confidence interval, 13% to 39%). Hemoccult was positive in 21% of intraluminal recurrences, 33% of all new primary tumors, and 29% of Dukes A or B cancers; HemoQuant was elevated in 24%, 28%, and 29%, respectively. Sensitivity for polyps 1.0 cm or larger was 13% by Hemoccult and 11% by HemoQuant. In the group of relatives, estimated sensitivity for cancer at 1 to 3 years of follow-up was 25% to 33% by Hemoccult, not significantly different from the 29% to 43% by HemoQuant.
Based on our observations in the screening setting, fecal blood appears to be a poor marker for colorectal neoplasia. Most cancers and the vast majority of polyps will be missed. Hemoccult and HemoQuant are similarly insensitive.
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