Dual-wavelength point zig-zag scanning of zones on thin-layer chromatograms as a tool for quantitative assay

Sparteine metabolism in a Nigerian population

The oxidative metabolism of sparteine has been investigated in a Nigerian population. The distribution of metabolic capacities was shown to be skewed with two subjects (2/97, 2.1%) being relatively deficient in their ability to produce the dehydrometabolites. These observations afford evidence that sparteine oxidation is under polymorphic control in Nigerians.

Quantitation of IgE and carcinoembryonic antigen (CEA) by optical beam deflection (OBD) measurement of dot-immunobinding assay patterns visualized by an ELISA technique

Dot-immunobinding assays of IgE and CEA were performed by a conventional dot-ELISA technique with diaminobenzidine staining, and the quantitative results were compared by densitometry and a new, spectroscopic, optical beam deflection (OBD) method using the same membrane. It was possible with the OBD method to detect quantities of these substances at least ten times smaller than with densitometry. Better intra-assay reproducibility for IgE and CEA measurements was obtained by the OBD method. The measurable ranges of the OBD method was broader than that of densitometry, because dark bands caused OBD in proportion to their color densities. When the dot-immunobinding assay with OBD measurement for CEA was also compared with a microtube ELISA using biotin-avidin conjugates, the sensitivities and reproducibilities of the two methods were found to be similar, with a correlation coefficient of 0.991.

Progress in densitometry for quantitation in planar chromatography

The principal methods for obtaining quantitative information from separations performed by planar chromatographic techniques are reviewed. Recent advances in obtaining structural information for sample identification of separated components are also discussed. Reasonable expectations concerning future developments in densitometry are made.

Optical isomerization of R(-)-clidanac to the biologically active S(+)-isomer in guinea-pigs

Optical isomerization of clidanac (RS-6-chloro-5-cyclohexyl-1-indancarboxylic acid, I), an anti-inflammatory drug having a chiral centre in its molecule, was evaluated in guinea-pigs. After oral administration of R(-)-I, the biologically active S(+)-isomer was detectable in the plasma, in the early stages. At 3 h after dosing R(-)-I, the plasma contained above 90% of the S(+)-isomer. Little conversion of S(+)-I to R(-)-I was observed. This may account for the equivalent in vivo activities of R(-)- and S(+)-I in this species. Determination of the enantiomeric composition required derivatization of the enantiomers to their diastereomeric amides after which thin layer chromatography (t.l.c.) was used for the separation. The quantitative determination of the compounds so-separated was accomplished by in situ measurements of the u.v.-reflectance. The t.l.c.-u.v.-densitometric procedure was also used to determine the plasma concentration of I.

Quantitative analysis of cephamycin C in fermentation broths by means of thin-layer spectrodensitometry

A method has been developed that consists of one-dimensional thin-layer chromatography of the samples on pre-coated silica gel 60F254 plates followed by an in situ spectrophotometric evaluation of the chromatograms at 273 nm. Statistical evaluations showed a linear calibration (r2 greater than 0.999) for the range of 0.2-20 microgram/spot. The relative standard deviations for broth samples containing 1.505 and 12.47 microgram Cephamycin C per spot were 3.61 and 1.07%, respectively. The recovery was virtually quantitative: 97.6%. The correlation with a liquid chromatographic method was quite acceptable with r2 = 0.99124 and b = 0.998 (slope).

Atypical GM1 ganglioside accumulation in a case of juvenile amaurotic idiocy

The brain and liver from a 7-year-old Japanese girl with juvenile amaurotic idiocy were examined neuropathologically and biochemically. Visceromegaly and skeletal abnormalities were absent. Nerve cells in the central nervous system were swollen and contained fine fat granules. Electronmicroscopically, there were large numbers of irregular bodies in the perikarya and these corresponded to the curvilinear and membranous cytoplasmic bodies. Lipid analysis of the brain revealed that GM1 ganglioside was increased in the parietal and occipital areas, while the frontal lobe showed a normal ganglioside pattern. N-Acetyl neuraminic acid (NANA) content in all areas was not elevated. Determinations of beta-galactosidase activity were within normal ranges. The liver had no accumulation of GM1 ganglioside and showed a normal beta-galactosidase activity. These unusual findings in GM1 gangliosidosis were discussed.