Changes in the levels of prostaglandins and thromboxane and their roles in the accumulation of exudate in rat carrageenin-induced pleurisy — a profile analysis using gas chromatography-mass spectrometry —

Injection of γ-carrageenin into t he pleural cavity of rats caused the accumulation of the pleural exudate. When levels of prostaglandins (PGs) and thromboxane (TX) B₂ were quantified by gas chromatography-mass spectrometry as their methyl ester (ME)-dimethyllisopropylsilyl (DMiPS) ether or ME-methoxine-DMiPS ether derivatives, 6-keto-PGF_1α reached the maximum at 1 hr after carrageenin, then PGE₂ and TXB₂ showed peaks at 3 hr and waned off before 9 hr. he PGF_2α level was kept low, but PGD₂, PGE₁ and PGF_1α were not detected. Aspirin (100 mg/kg, i.p.) significantly decreased the PG and TXB₂ levels and suppressed the rate of plasma exudation until 5 hr, but did not at 7 hr, when it was measured by the amount of exuded pontamine sky blue injected intravenously. OKY-025 (300 mg/kg, i.p.), a selective TXA synthetase inhibitor, and tranylcypromine (20 mg/kg, i.p.), a PGI synthetase inhibitor, could not extensively inhibit the accumulation of the exudate. These results suggest that the cyclooxygenase products of arachidonic acid, particularly PGE₂, definitely play an important role in the exudation during the first 5 hr.     

An electron microscopic study on the mating tube formation in the heterobasidiomycete Tremella mesenterica

Ultrastructure of the mating tube formed in yeast haplont of the heterobasidiomycete Tremella mesenterica was studied by electron microscopy. Cell wall of the mating tube emerged as evagination of the inner layers, rupturing outer layers of the mother cell wall. Comparison with budding cells suggested that the tube emergence place at bud scar and the process of tube emergence was the same as that of bud emergence. Electron transparent vesicles of 0.1 m diameter were scattered in the cytoplasm of the mating tube. Nucleus-associated organelle was located at one side of the nuclear envelope which extended towards the mating tube. A few microtubules were detected in the mating tube, but their association with a nucleus was not clear. The cytoplasmic structure of the mating tube was discussed in comparison with that of hyphae of the filamentous fungi.     

Isolation and identification of 23,25-dihydroxyvitamin D3, an in vivo metabolite of vitamin D3

Vitamin D supplemented rats produce a metabolite of 25-hydroxy[3 alpha-3H]vitamin D3 that is easily separated from known metabolites by using high-performance liquid chromatography. The production of this metabolite in vivo as well as 1,25-dihydroxyvitamin D3, 24(R),25-dihydroxyvitamin D3, and 25-hydroxyvitamin D3 26,23-lactone is largely if not totally eliminated by nephrectomy. Kidney homogenates from vitamin D supplemented chickens incubated with 25-hydroxyvitamin D3 produce significant quantities of the new, unknown metabolite. This metabolite was isolated in pure form from such incubation mixtures by using both straight-phase and reversed-phase high-performance liquid chromatography. This metabolite has been positively identified as 23,25-dihydroxyvitamin D3 by ultraviolet absorption spectrophotometry, mass spectrometry, and derivatization. This structure was confirmed by chemical synthesis of both C-23 stereoisomers. Although the natural product exactly comigrates with one of the synthetic isomers, the exact stereochemistry of the natural product remains unknown. It is possible that this new metabolite is an intermediate in the biosynthesis of 25-hydroxyvitamin D3 26,23-lactone.     

Amino acid substitution of mating factor of Saccharomyces cerevisiae structure-activity relationship.

Analogs of the mating factor of $\text{Saccharomyces cerevisiae}$, Trp¹- Trp³-Leu-Gln-Leu⁶-Lys⁷-Pro⁸-Gly-Gln-Pro¹¹-Met¹²-Tyr¹³, from which amino acids were eliminated or substituted for other amino acid, were synthesized. These analogs showed lower biological activity than the natural mating factor if assayed after 6 hours incubation with $\text{a}$-mating type cells of $\text{S. cerevisiae}$. However, if assayed after 24 or 48 hours incubation, the situation changed, i.e. the analogs in which Leu⁶ or Lys⁷ were replaced by the corresponding D-isomer, showed higher mating factor activity than the unsubstituted mating factor. The same result was obtained with the analogs in which Met was replaced by norleucine.     

The presence of an adenosine-5'-triphosphatase dependent on 6S tubulin and calcium ions in rat brain microtubules.

An ATPase activity was found in rat brain microtubules prepared by successive cycles of polymerization and depolymerization. On phosphocellulose column chromatography, the ATPase activity was recovered in the fraction eluted with 0.6 M KCl and containing the microtubule associated proteins. The ATPase activity was markedly stimulated by the addition of purified brain 6S tubulin, and the stimulation was dependent on the presence of Ca2+ ions. Approximately 50 pmol of purified 6S tubulin was required for the maximal stimulation in the presence of 8 microgram of microtubule associated proteins. The specific activity was 8 to 13 nmol of ATP hydrolyzed per min per mg of protein at 37 degrees C, and the Km value for ATP was 3 X 10(-5) M in the presence of added tubulin.     

Field test and experimental use of CYBEST model 2 for practical gynecologic mass screening

CYBEST is an automated cytologic screening system for uterine cancer utilizing a pattern-recognition image-analysis system. The prototype was developed in 1972 following fundamental studies of feature extraction, feature evaluation using ambiguity differential functions and segmentation of cell and nuclear images. Model 2 was developed in 1974 with an improved mechanism and function. The parameters employed are nuclear size, nuclear optical density, N/C ratio and nuclear shape. The data of field tests using 220 samples containing three cases of dysplasia, 110 cases of carcinoma and 107 nonmalignant cases were as follows: two false-negative cases (1.8%), 13 false positives (12.1%) and one reject (0.9%). This system was experimentally tested for practical mass population screening with 1,829 cases including 17 atypical cases (four epidermoid carcinomas). The data were as follows: no false-negative cases and 581 false-positive cases (32.1%). Of the latter, 311 cases (17.2%) were pathologic samples, such as severe cervicitis, senile colpitis, Trichomonas infestation, etc., and the remaining 270 cases (14.9%) were within physiologic limits, corresponding to true false-positive samples.     

Glycoprotein galactosyltransferase activity in synaptic junctional complexes isolated from rat forebrain

A synaptosomal plasma membrane fraction and its junctional and nonjunctional subfractions were isolated and analyzed for glycoprotein galactosyltransferase activity. The nonjunctional components fraction had the highest specific activity in the presence of exogenous acceptor, suggesting an enrichment of enzyme in this fraction. The synaptic junctional complex fraction had the highest specific activity in the absence of added acceptor, suggesting that there is a relative enrichment of endogenous acceptors for this galactosyltransferase within the synaptic junctional complex.Presented in part at the 6th meeting of the Society of Neuroscience, Toronto, Ontario, November, 1976 (Goodrum, Bosmann, and Tanaka, 1976)     

Polyamine prevention of inhibition of rat liver isoleucyl-tRNA formation by poly(G), poly(I) or ribosomes.

It is shown that rat liver isoleucyl-tRNA formation in the presence of Mg²⁺ is inhibited by poly(G), poly(I) or ribosomes and that this inhibition is prevented by polyamines. The inhibition is found to be noncompetitive with respect to tRNA.