Drop assay

Alkaloid Head-drop assay Frog, EL Cat References... 

Quaternary derivatives of the yohimbe alkaloids have recently been shown to exhibit paralyzing activity (48, 111). The best of the series, iV-methylhexahydrotetrabyrinium chloride, is effective in a dose of 3.4 mg./kg. in the rabbit head-drop assay and it has a very low toxicity. 

Products whose main alkaloids are curarine and calebassine are usually somewhat less active. Thus, a curare from southern Venezuela, of Mainatari origin, also collected by Natterer in 1830, had LD qq 4 mg/kg. Waser (484) reported that head-drop assay in the mouse of alkaloid fractions isolated by... 

With the large amount of curare brought back by the Gill-Merrill expedition in 1938 (548) and the development of the rabbit head-drop assay by Holaday, the situation began to change. Squibb was able to make a standardized product, Unauthenticated Extract of Curare, Intocostrin, one unit of which was equivalent to 0.15 mg tubocurarine. This preparation was made available to medical researchers in the United States. In 1938/39 Bennett and McIntyre introduced the use of curare in electro-shock therapy, to prevent the injuries which up till then had been a common occurrence during the... 

Properties. A high volatile western Kentucky bituminous coal, the tar yield of which by Fischer assay was ca 16%, gave a tar yield of ca 26% at a pyrolysis temperature of 537°C (146—148). Tar yield peaked at ca 35% at 577°C and dropped off to 22% at 617°C. The char heating value is essentially equal to that of the starting coal, and the tar has a lower hydrogen content than other pyrolysis tars. The product char is not suitable for direct combustion because of its 2.6% sulfur content. 

Sevin. 1-Naphthalenol methylcarbanate [63-25-2] (Sevin) (44) was developed as an insecticide. However, the conception of the molecule, in the mid-1950s, was as a possible herbicide. The compound ultimately was useless as a herbicide, but in routine testing it was discovered to be an excellent insecticide. Sevin was active in the oat mesocotyl assay and demonstrated weak auxin-like activity. During the development of Sevin, it caused massive apple drop in the western United States in an orchard being treated for insects. It is used (ca 1993) as an abscising agent to thin apples. 

Situation A cream that contains two active compounds was investigated over 24 months (incomplete program if today s ICH standards are applied, which require testing at 0, 3, 6, 9, 12, 18, and 24 months). The assays resulted in the data given in file CREAM.dat. Program SHELFLIFE performs a linear regression on the data and plots the (lower) 90% confidence limit for the regression line. For each full time unit, here months, it is determined whether this CL drops below levels of y = 90% resp. y = 95% of nominal. Health authorities today require adherence to the 90% standard for the end-of-shelf-life test, but it is to be expected that at least for some products the 95% standard will be introduced. 

Figures 7.57a-c show the acceptor, donor, and reference spectra of 48 pM propranolol at the end of 15 h PAMPA assay using 20% wt/vol soy lecithin in dode-cane. The sum of the donor (3 pM) and the acceptor (<1 pM) well concentrations indicates that 45 pM is lost to the membrane. In the absence of sink-creating surfactant, only a trace of propranolol reached the acceptor wells at the end of 15 h, with 94% of the compound trapped in the membrane, compared to 19% in the 2% wt/vol DOPC case (Table 7.5). The effective permeability in 20% soy dropped to 1.8 x 10 6cm/s, compared to the DOPC value of 10.2 x 10 6cm/s.

Qualitative tests for the presence of pectinesterase, based on a color change of such indicators as Bromothymol Blue or Bromocresol Green, after de-esterification of pectin, are simple and very useful these tests are used as drop tests when checking chromatographic columns85,97 100 or for a qualitative assay of pectinesterase in culture filtrates, using the cup-plate method.113... 

Arginine prototrophs were screened for Ars-activity by using the qualitatively X-SO4 assay. After growing cells on plate during anaerobic (A) or aerobic (B) adaptation, X-SO4 was dropped on colonies of strain MR16 generated by transformation with plasmid pMR16. 

The inoculum for the assay is prepared by growing Ochromonas for 4-6 days in the basal medium supplemented with 10 m ig/ml of thiamine. The culture is then diluted 1 100 with basal medium a drop of this dilution serves as an inoculum for each assay flask. There is no... 

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