ABSTRACT
Solution plasma (SP) treatment in combination with oxidizing agents, i.e., hydrogen peroxide (H2O2), potassium persulfate (K2S2O8) and sodium nitrite (NaNO2) were adopted to chitosan degradation in order to achieve fast degradation rate, low chemicals used and high yield of low-molecular-weight chitosan and chitooligosaccharide (COS). Among the studied oxidizing agents, H2O2 was found to be the best choice in terms of appreciable molecular weight reduction without major change in chemical structure of the degraded products of chitosan. By the combination with SP treatment, dilute solution of H2O2 (4-60mM) was required for effective degradation of chitosan. The combination of SP treatment and dilute solution of H2O2 (60mM) resulted in the great reduction of molecular weight of chitosan and water-soluble chitosan was obtained as a major product. The resulting water-soluble chitosan was precipitated to obtain COS. An inhibitory effect against cervical cancer cell line (HeLa cells) of COS was also examined.
Subject(s)
Antineoplastic Agents/pharmacology , Chitin/analogs & derivatives , Chitosan/chemistry , Oxidants/chemistry , Plasma Gases/chemistry , Antineoplastic Agents/chemistry , Chitin/chemistry , Chitin/pharmacology , HeLa Cells , Humans , Hydrogen Peroxide/chemistry , Kinetics , Molecular Structure , Molecular Weight , Oligosaccharides , Oxidation-Reduction , Potassium Compounds/chemistry , Sodium Nitrite/chemistry , Sulfates/chemistryABSTRACT
In order to enhance the sensitivity of LC-MS, a novel on-line sample enrichment system was integrated by inserting a column-switching device containing a peak parking loop after conventional LC column and UV detector. The system consists of conventional LC, micro-LC, a parking loop, and a micro-precolumn, all connected through one eight-port switching valve. An analyte peak of interest detected on the conventional LC is stored in the parking loop with an appropriate amount of added water. The analyte is then directly transferred to the micro-precolumn to be concentrated, and then eluted from the precolumn with linear gradient and separated by the micro-LC column. The sensitivity of LC-MS can be increased by a factor of up to a 100. By combining the micro-LC column with ESI-TOF-MS, some structural information including accurate molecular weight were obtained from analyte samples in the pmol range.
Subject(s)
Spectrometry, Mass, Electrospray Ionization/instrumentation , Chromatography, Liquid/methods , Molecular Weight , Particle Size , Pharmaceutical Preparations/chemistry , Sensitivity and Specificity , Spectrophotometry, Ultraviolet/methodsABSTRACT
In consecutive 50 diabetic patients hospitalized for medical education, without subjective symptoms of autonomic neuropathy (DM group), performed treadmill walking stress test and thermography, for clarify the feature of the pattern typical of diabetic autonomic neuropathy. Thermal images were collected, before, immediately after, 3, 6, 12 minutes after walking. The mean temperature of toes fell more than 1 degree C than that of baseline level and returned within 0.5 degrees C of baseline level within 6 minutes (N type) in 66% of 30 normal subjects (C group) and 24% of DM group. In 10% of C and 24% of DM, the temperature fell but not returned within 0.5 degrees C of baseline level in 6 minutes (D type). In 17% of C and 38% of DM, the temperature changed within 0.5 degrees C (F type), or rose more than 0.5 degrees C after exercise (U type) in 7% in C and 14% in DM groups. Pts D, F group, have more complications (HbA1c, nephropathy, retinopathy or somatic neuropathy), but not so in C, U type. We concluded D, F types were the typical thermographic features of the toes of pts with diabetic autonomic neuropathy.
Subject(s)
Diabetic Neuropathies/diagnosis , Exercise Test , Thermography , Toes/physiopathology , Walking/physiology , Aged , Diabetic Foot/prevention & control , Female , Humans , Male , Middle Aged , Patient Education as Topic , Skin Temperature , Toes/blood supply , Toes/innervationABSTRACT
We discovered novel calibrants, several 2,2,6,6-tetraalkylpiperidinyl derivatives, for accurate mass measurements by electrospray ionization mass spectrometry (ESI). These compounds showed excellent performance as internal calibrants for the accurate mass measurement in ESI-MS, without problems arising from differences in the ionization efficiencies between the analytes and calibrants.
ABSTRACT
Skin sensitization potential of low molecular weight chemicals was assessed by analyzing peptide-conjugate formation. Chemicals were incubated with a peptide, glutathione, and resultant mixtures were analyzed by mass spectrometry. Eighteen chemicals were assessed, and new peaks corresponding to chemical-peptide conjugates were detected for 13 of 14 known sensitizers. Conjugates were not detected for 4 negative chemicals. The method has advantages as a simple screening assay for assessing the sensitization potential of chemicals.
