Biomedical subjects

M L Wen

Publications and source records attributed to M L Wen.

8 recordsLinked to original sources

PubMed2001

Construction and performance characteristics of new fentanyl-selective plastic membrane electrode.

The construction and performance characteristics of an ion-selective electrode for fentanyl-drug cation, based on an ion-pair complex with tetrakis[3,5-bis-(trifluoromethyl)phenyl]borate anion in a PVC matrix were studied. A linear response for 1 x 10(-5) mol dm-3 to 1 x 10(-2) mol dm-3 drug with a slope of 57.9 +/- 0.5 mV/decade was established. The optimum pH range was 2 to 6. The lower detection limit was 6.29 x 10(-6) mol dm-3 fentanyl citrate (2.1165 micrograms cm-3 fentanyl). There were negligible interferences from a number of inorganic cations, structural analogues, and some common drug additives in injections. The electrode proposed has been successfully applied to determine fentanyl citrate in injections. The results correlated well with those obtained by the United States Pharmacopoeia standard procedure.

Chemistry, Clinical↗

PubMed2001

Fentanyl-selective polymeric membrane electrode.

A poly (vinyl chloride) membrane electrode with dibutyl phthalate as plasticizer based on a fentanyl-tetrakis(4-chlorophenyl)borate ion-pair complex for the determination of fentanyl citrate in injections is described. A linear response over the range 1 x 10(-5) mol.dm-3 to 1 x 10(-2) mol.dm-3 drug with a slope of 59.3 +/- 0.6 mV/decade was established. The optimum pH range was 1 to 6. The lower detection limit was 8 x 10(-6) mol.dm-3 fentanyl citrate (2.7 micrograms cm-3 fentanyl). There were negligible interferences from a number of inorganic cations, structural analogues, and some common drug additives used in injections. The electrode proposed has been successfully applied to determine fentanyl citrate in injections. The results correlated well with those obtained by the United States Pharmacopoeia standard procedure.

Chromatography, High Pressure Liquid↗

PubMed2000

Plastic membrane electrode for the potentiometric determination of pethidine hydrochloride in pharmaceutical preparations.

A novel poly(vinyl chloride) membrane electrode with dibutyl phthalate as plasticizer based on the pethidine-tetraphenylborate ion-association complex as ion-exchange site for the determination of pethidine hydrochloride in injections and tablets was developed. A linear response for 1 x 10(-5) to 1 x 10(-2) mol/L drug with a slope of 51.77 mV/decade was established. The optimum pH range was 2-8. The lower detection limit was 2.18 x 10(-6) mol/L. There were negligible interferences from a number of inorganic and organic cations and some common drug excipients. The electrode proposed had been successfully applied to determine pethidine hydrochloride in tablets and injections. The results correlated well with those obtained by the United States Pharmacopoeia standard procedure.

Calibration↗

PubMed1999

Potentiometric sensor for methylene blue based on methylene blue-silicotungstate ion association and its pharmaceutical applications.

A methylene blue (MB) poly(vinyl chloride) membrane sensor based on MB-silicotungstate (SLT) ion association as electroactive material was described. The linear response covered the range 1 x 10(-3)-1 x 10(-6) mol x dm(-3) MB solution, with a slope 52.0+/-0.8 mV decade(-1) (pH range 3.0-10.0). The detection limit was 7.65 x 10(-7) mol x dm(-3). The electrode showed stability, good reproducibility and fast response. Interferences from common inorganic cations, some organic base were negligible. These characteristics of the electrode enabled it to be used successfully for the determination of MB in injection. There was a good agreement for the results of MB content in injection between potentiometric method and USP standard procedure.

Calibration↗

PubMed1994

An affinity column method for determination of the immunoreactivity of 131I-chimeric L6 monoclonal antibody and comparison to in vivo tumor localization.

An affinity column method was developed to determine the immunoreactivity of 131I-ChiL6 (chimeric L6 monoclonal antibody), a candidate for radioimmunotherapy. This method involved assessing the binding of the radiolabeled antibody to antigen containing membranes bound to a Reacti-gel agarose matrix. The immunoreactivity determined by the affinity column method correlated to other in vitro binding assays including the Lindmo infinite antigen excess method. In tumor-bearing mice which had been injected with 131I-ChiL6, which possessed high immunoreactivities (90-82%), a high tumor uptake (13.5-10.5% ID/g) was observed. A decrease in tumor uptake (5.2-4.8% ID/g) was observed with 131I-ChiL6 samples of low immunoreactivity (42% and 31%, respectively). While a moderate loss of immunoreactivity (4-18%) of the 131I-ChiL6 samples could be detected by the affinity column method, the loss of tumor uptake in vivo observed was not as significant. This method was found to be an efficient and sensitive method for detecting damage to the antibody during radiolabeling and applicable as a quality control method for clinical trials. This rapid method, compared to the other in vitro binding assays (including the Lindmo infinite antigen excess method) has distinct advantages as a quality control method since it requires less manipulation and can be semi-automated.

Adenocarcinoma↗

PubMed1990

[Rate of G gamma and A gamma chains in Dong ethnic newborns and gene mapping of a case with high G gamma value].

The G gamma to A gamma ratio of fetal hemoglobin in 120 cord blood samples of Dong ethnic newborns distributed over the Dong Autonomous Regions in Guangxi and Hunan provinces were determined with the method of polyacrylamide gel electrophoresis. The result showed that a case has the high G gamma value of 81.4% while 119 babies have the normal G gamma values of 56 to 76% (69.4 +/- 3.1%). The high G gamma case was identified as G gamma-AG gamma-A gamma/G gamma-A gamma genotype.

Asian People↗

PubMed1989

Effects of high-rise living on physical and mental development of children.

Effects of high-rise living on infants' development were investigated in 1987-1988 in a high-rise residential area in Tokyo, using questionnaires on the daily behaviors of a total of 1,045 infants, completed by mothers and kindergarten teachers. Infants of high-rise living showed a delayed independence in fundamental daily customs compared with those of low-rise living. This could be ascribed to an over-attachment of mothers of high-rise living with their infants resulting from a reduced number of outings.

Activities of Daily Living↗

PubMed1986

Site-specifically modified 111In labelled antibodies give low liver backgrounds and improved radioimmunoscintigraphy.

Site-specific modification of monoclonal antibodies at their oligosaccharide had previously been demonstrated to produce excellent 111In imaging in a xenograft model using a Brown Norway (BN) rat lymphoma and a rat anti-BN MHC monoclonal antibody [Lee C. et al. Fed. Proc. Abstr. 43 3014 (1984)]. These results are due, in part, to lack of liver uptake, so we wanted to evaluate the extent of hepatic uptake observed with different monoclonal antibodies in normal mice. Biodistribution data were obtained for four monoclonal antibodies by first modifying each antibody at its carbohydrate with a diethylenetriaminepentaacetic acid (DTPA) derivative. The antibodies were then labelled with 111In and injected into normal mice. Images were obtained 24 h post-injection, and at 48 h the mice were dissected and the tissue-to-blood (T:B) ratios determined. T:B ratios were approximately 1 (or less) for every organ evaluated, indicating minimal non-specific uptake into these organs. Data is also presented for the BN-rat system which shows excellent localization into the tumor xenograft and low non-specific organ uptake. These data indicate that modification of antibodies site-specifically at their oligosaccharide results in minimal non-specific uptake into non-target tissues and enhanced localization into the tumor target, and that this may represent a preferred method for production of 111In labelled antibodies.

Animals↗