A newly developed assay for melatonin using cells expressing human mel-1a receptor.

We have developed a radioreceptor binding assay (RRA) method for melatonin using membranes from Chinese hamster ovary cells that can stably express human mel-1a receptors. We measured melatonin levels in plasma samples collected every 4h for 24h using the RRA and radioimmunoassay (RIA) methods, simultaneously. There was a statistically significant correlation between the melatonin levels measured by the two methods, this newly developed method providing a sensitive bioassay. As it is possible to circumvent the cross-reactivity usually occurring in the RIA method, this method may be an important tool for detecting bioactive substances relative to the mel-1a receptor.

A comparison of biopsy through a parasternal anterior mediastinotomy under local anesthesia and percutaneous needle biopsy for malignant anterior mediastinal tumors.

The various methods of treating the numerous types of anterior mediastinal neoplasms are undergoing refinements; however, prior to the commencement of any treatment, an accurate histologic diagnosis must be established. We conducted a retrospective analysis of biopsies performed through a parasternal anterior mediastinotomy (PAM) on 21 patients with an anterior mediastial mass suspected of being malignant by computed tomography (CT) and other clinical information. Patients with possible localized thymomas were excluded. Mediastinotomy, which enables relatively large tissue samples to be taken, was performed through the bed of the second or third costal cartilage under local anesthesia. In 19 of the 21 patients (90%), the histologic diagnosis made from the mediastinotomy biopsy was identical to the final diagnosis. Conversely, although the tissue obtained from needle biopsy was sufficient for a histologic diagnosis in 11 of 12 patients, the histologic diagnosis made from the needle biopsy was the same as the final diagnosis in only 5 of 10 patients (50%). Thus, diagnostic accuracy was significantly higher in the mediastinotomy biopsies than in the needle biopsies (P = 0.0318). Moreover, the mediastinotomy biopsy specimens revealed subtypes of lymphomas and germ cell tumors. All of the patients from whom a mediastinotomy biopsy had been taken began appropriate therapy without delay according to the histologic diagnosis. These results suggest that the PAM approach should be chosen as the preferred method of biopsy for suspected malignant anterior mediastinal tumors.

Induction of enzymes involved in fatty acid beta-oxidation in Pseudomonas fragi B-0771 cells grown in media supplemented with fatty acid.

Induction of the enzymes involved in fatty acid beta-oxidation in Pseudomonas fragi B-0771 cells grown in a medium containing straight chain saturated fatty acids was studied. The acyl-CoA dehydrogenase (ACDH) activity was induced during the exponential phase in cells grown in palmitic acid-supplemented medium, reached a maximum at the early stationary phase, and then gradually decreased thereafter. Changes in the overall activities of 2-enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase, both existing on the multienzyme complex (HDT) involved in fatty acid beta-oxidation, were similar to that in ACDH activity. Straight chain saturated fatty acids having more than 6 carbon atoms could induce both the ACDH and HDT activities, and C13-C15 fatty acids caused the greatest induction of both activities. Changes in the overall activities of 2-enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase correlated with that in the amount of the alpha-subunit of HDT during the entire culture period in the medium containing palmitic acid. Surprisingly, the stoichiometry of the alpha- and beta-subunit proteins of HDT was not maintained into the stationary phase culture, though the genes encoding the alpha- and beta-subunits are tandemly coded in bacterial genomic DNA.

Cholesterol, phytosterol and polyunsaturated fatty acid levels in 1982 and 1957 Japanese diets.

The dietary intake of cholesterol, phytosterol and PUFA in Japanese was investigated to obtain information on dietary parameters related to coronary artery disease. Three daily menus for both 1957 and 1982 were prepared based on the daily per capita consumption of foods and nutrient intakes from national surveys. From 1957 to 1982, the average daily intake of cholesterol rose 2.1-fold from 183 to 376 mg while that of phytosterol remained at about 373 mg. Daily intakes of total fatty acid (19.2 g), PUFA (7.3 g), MUFA (5.8 g) and SFA (6.1 g) in 1957 increased in 1982 to 48.7 g, 11.9 g, 19.5 g and 17.3 g, respectively. The ratio of PUFA/SFA decreased to 56% from 1.23 in 1957 to 0.69 in 1982 and the PUFA/MUFA ratio also decreased to 48%. The PUFA/cholesterol ratio was lower in 1982 (31.8) than in 1957 (42.6), and the decrease in the phytosterol/cholesterol ratio to 46% was greater than that in the PUFA/cholesterol ratio (which only fell to 75% of the 1957 value). Thus, comparison of the 1982 and 1957 intakes indicated the increase in risk factors, cholesterol and SFA intake, and the decrease in the ratio of PUFA/SFA in the Japanese population during the past few decades.