[Comparison between kinetics of positive inotropism of ibopamine and ouabain]

AIM

To compare the kinetics of positive inotropism between ibopamine (Ibo) and ouabain (Oua).

METHODS

The isolated right papillary muscle of cat was used to assess the positive inotropic effects by cummulative concentrations of Ibo and Oua. The maximal effects was recognized as the contraction just before the appearance of spontaneous contraction. A Hill equation was developed by using lg [E/(Emax-E)] vs lg C.

RESULTS

The S value of Ibo was smaller than that of Oua, causing C95/C5 (ratio of concentrations producing 95%/5% of Emax) of Ibo (264) elevenfold as large as Oua (22.9). Comparing with Oua, concentrations of Ibo initiating effects were lower, the slope was smaller, and higher concentrations were required for producing maximal effect. During drug concentration declining, the effect-concentration curve of Ibo showed a counter-hysteresis loop, more remarkable than Oua.

CONCLUSION

The changes in positive inotropism of Ibo against drug concentrations were less than those of Oua.

[Effect of antiserum against dynorphin A administered intrathecally on spinal cord injury (SCI) of rats and its significance]

The antagonistic effects of antisera against dynorphin A, beta-endorphin, and leu-enkephailin administered intrathecally on secondary SCI were observed and compared after moderate SCI using principle of antigen-antibody neutralization reaction. The protective effect of antiserum against dynorphin A was most prominent on secondary SCI and the effect was more prominent when administered at 24 hours following SCI than when administered at 0 hour four hours, one week or two weeks following SCI. That suggests increase of dynorphin A level in spinal cord tissue may play an active role in the early stage, but its harmful effect on secondary SCI will be more and more prominent after accumulation of excessive dynorphin A.

[Effects of intrasubarachnoid space injection of anti dynorphin A1-13 serum or nor-BNI on the recovery of spinal cord injury in rats]

A pronounced and reversible spinal cord compression injury was performed by the compression of a metal plate 2.2mm x 5. Omm in size to the exposed spinal dura and loaded with 35g weight for 5 minutes at T7-8. Anti dynorphin serum at 10 microliters (1:30000) or kappa antagonist nor-BNI at 100 ng was administered intrasubarachnoidly shortly after the injury, with half dose applied 1, 2, 3 h after the injury for another three times. The recovery of neurological function was investigated. The results showed that the recovery of the muscle tension and motor function of the hindlimb in anti dynorphin serum group is markedly faster than that in both control and nor-BNI groups. Also the recovery of motor function in nor-BNI group is favourable at the earlier stage of injury, comparing to the control group. There were no significant differences in the change of mean arterial pressure and blood physiological parameters among the three groups.

Escherichia coli RecG and RecA proteins in R-loop formation

Escherichia coli rnhA mutants devoid of RNase HI exhibit constitutive stable DNA replication, cSDR, which is thought to be initiated from R-loops stabilized in the absence of RNase HI. We found that a combination of an rnhA and a recG mutation is lethal to the cell. recG mutations that inactivate the helicase activity of RecG protein and inhibit reverse branch migration of Holliday junctions impart phenotypes resembling those of rnhA mutants. Thus, recG mutants display cSDR activity, and recG polA double mutants are inviable as are rnhA polA double mutants. These results suggest that the RecG helicase has a role in preventing R-loop formation. A model that R-loops are formed by assimilation of RNA transcripts into the duplex DNA is discussed. The model further postulates that RecA protein catalyzes this assimilation reaction and that RecG protein counteracts RecA in this reaction, resolves R-loops by its helicase activity, or does both.

[The change of platelet number in patient with acute myocardial infarction and its clinical significance]

Platelet number and alpha-granule membrane protein (GMP-140) level on platelet surface were determined in 20 patients with acute myocardial infarction (AMI) and 20 normal subjects. The results showed that platelet number decreased significantly after AMI, especially on the second day after onset and that the level of GMP-140 increased rapidly after AMI and reached a peak on the second after the attack. Both returned to the normal on the 5-7th day after the heart attack. Correlative analysis between increase of serum CK-MB and platelet number was negative (r = -0.6123, P < 0.005), and positive between that and GMP-140 level (r = 0.5895, P < 0.01). Platelet number decreased markedly in cases with heart failure and cardiac death. The results indicate that platelets are involved in the pathological process of AMI.

RecA, Tus protein and constitutive stable DNA replication in Escherichia coli rnhA mutants

Constitutive stable DNA replication (cSDR), which uniquely occurs in Escherichia coli rnhA mutants deficient in ribonuclease HI activity, requires RecA function. The recA428 mutation, which inactivates the recombinase activity but imparts a constitutive coprotease activity, blocks cSDR in rnhA mutants. The result indicates that the recombinase activity of RecA, which promotes homologous pairing and strand exchange, is essential for cSDR. Despite the requirement for RecA recombinase activity, mutations in recB, recD, recJ, ruvA and ruvC neither inhibit nor stimulate cSDR. It was proposed that the property of RecA essential for homologous pairing and strand exchange is uniquely required for initiation of cSDR in rnhA mutants without involving the homologous recombination process. The possibility that RecA protein is necessary to counteract the action of Tus protein, a contra-helicase which stalls replication forks in the ter region of the chromosome, was ruled out because introduction of the tus::kan mutation, which inactivates Tus protein, did not alleviate the RecA requirement for cSDR.

Absence of a direct role for RNase HI in initiation of DNA replication at the oriC site on the Escherichia coli chromosome

On the basis of the experiments carried out with rnhA224 mutants, we previously concluded that RNase HI is not essential for initiation of Escherichia coli chromosome replication at oriC (T. Kogoma, N.L. Subia, and K. von Meyenburg, Mol. Gen. Genet. 200:103-109, 1985). In light of the recent finding that rnhA224 is a UGA nonsense mutation which can be leaky in certain genetic backgrounds, we reexamined this conclusion with the use of rnhA339 (Null)::cat mutants. The possibility that recB+ is required for initiation at the alternative origins (oriKs) of replication in rnhA mutants was also tested. The results clearly indicated that RNase HI is not essential for oriC initiation and that recB+ is not required for initiation at oriK sites.

Brugia pahangi: identification and characterization of an aminopeptidase associated with larval molting

The third-stage larvae (L3) of the filarid parasite Brugia pahangi were surveyed for protease activity beginning with release from the mosquito vector through molting to the fourth-stage larvae (L4). A metalloaminopeptidase with a substrate preference for phenylalanine was released during the molting process. A screen of aminopeptidase inhibitors identified H-boroPhenylalanine-(pinacol) as highly effective, with a Ki of 1.3 x 10(-11) M. This peptidase inhibitor also arrested molting of L3 larvae in vitro at a concentration of 100 microM.

Requirement of homologous recombination functions for viability of the Escherichia coli cell that lacks RNase HI and exonuclease V activities

rnhA224 and rnhA339::cat mutants which lack RNase HI activity were found to constitutively express the sfiA::lacZ operon fusion in a recA+ lexA(+)-dependent manner. The sfiA::lacZ expression (indicating SOS induction) in rnhA mutants was increased to higher levels by the introduction of the recD1903 or recB21 mutation. The SOS induction in these cells was further enhanced by nutritional shift up from casamino acid medium to Luria broth. Although the extent by which the recD and recB mutations increased the sfiA expression in rnhA mutants was similar, the rnhA224 recB21 double mutant had plating efficiencies that were 25-fold lower on casamino acid plates and 5 x 10(5)-fold lower on Luria broth plates than the respective plating efficiencies of either rnhA224 recD or rnhA::cat recD double mutants. Whereas the recD mutation inactivates the exonuclease activity of the RecBCD (Exo V) enzyme without reducing the recombination proficiency of the mutant, the recB21 mutation abolishes both the exonuclease activity and recombination capability. Therefore, in the absence of both RNase HI and Exo V activities, homologous recombination functions become crucial for viability, particularly in Luria broth. Introduction of mutations in recA, recJ and recN exacerbated the phenotypes. It is proposed that R-loops which persist due to the lack of RNase HI activity can be removed by two alternative routes of DNA repair: one involving Exo V, Exo I and DNA polymerase I, and the other involving both the RecBCD and RecF pathways of homologous recombination activities. The isolation of RNA polymerase mutants that constitutively express the SOS response at high levels and exhibit remarkable broth-sensitivity lend strong support to the contention that increased amounts of the persisting R-loop in rnhA mutants growing in Luria broth give rise to a stronger SOS response.

[A preliminary research on the quality of musk]

In this paper liquid crystal b-PBPeB was adopted as the GC-stationary liquid phase. From the ether extract of musk, androsterone, muscone and cholesterol were identified. Comparative analysis of 13 samples of musk has proved this method to be useful in the quality evaluation of musk.

[Comparative GC analysis of essential oil in imported sandalwood]

The GC-fingerprint spectra of essential oils in imported sandalwood are established by the new technique of GC-relative retention value fingerprint spectrum (GC-FPS). According to the GC-FPS of samples, their chromatographic peaks, overlap ratio of peaks and eight strong peaks are studied comparatively.

Hepatic neoplasms in aflatoxin B1-treated, congenital duck hepatitis B virus-infected, and virus-free pekin ducks

To assess the effects of the combination of persistent hepadnavirus infection and chemical carcinogen exposure, aflatoxin B1 (AFB) was administered p.o. for 60 days to congenitally duck hepatitis B virus (DHBV)-infected and virus-free Pekin ducks, starting at 3 days of age, during a 28-month study. Hepatic neoplasia occurred only in AFB-dosed ducks. Hepatocellular carcinomas or biliary carcinomas occurred in 4 of 8 DHBV-infected and 3 of 4 DHBV-free ducks, and hepatocellular adenomas developed in 2 DHBV-infected AFB-dosed ducks that survived 20 months or longer. Altered foci of hepatocytes similar to those observed in chemical carcinogen-dosed rodents, characterized by enlarged eosinophilic hepatocytes or vacuolated cytoplasm, occurred in AFB-dosed ducks. Cells in foci or hepatic neoplasms did not contain histochemically detectable gamma-glutamyltranspeptidase but were distinguished from uninvolved parenchyma by altered glycogen content. Immunohistochemical staining indicated that DHBV core antigen persisted in liver, spleen, pancreas, and, to a lesser extent, kidney of most congenitally infected ducks up to 28 months of age. Hepatic neoplasms contained only patches of hepatocytes were detectable viral antigen. Southern blot analysis of restriction endonuclease-digested neoplastic and normal liver DNA revealed high molecular weight forms of DHBV DNA consistent with integration of viral DNA into the genome of hepatic neoplasms from 3 of 4 DHBV-infected ducks but not nontumorous liver. These findings indicate that AFB is a potent hepatic carcinogen in ducks and that persistent congenital DHBV infection did not contribute significantly to the emergence of hepatic neoplasia in ducks under these conditions.

Isolation and structure elucidation of 12beta-acetoxycoccinic Acid, 12beta-hydroxycoccinic Acid, 12alpha-acetoxycoccinic Acid, and 12alpha-hydroxycoccinic acid1

Four new triterpenoid acids, possessing a lanost-9(11)-en-3-one skeleton, were isolated from KADSURA HETEROCLITA. Based on chemical and spectral analyses, they were assigned as 12beta-acetoxycoccinic acid, 12beta-hydroxycoccinic acid, 12alpha-acetoxycoccinic acid, and 12alpha-hydroxycoccinic acid.

Electrostatic and steric control of electron self-exchange in cytochromes c, c551, and b5

The ionic strength dependence of the electron self-exchange rate constants of cytochromes c, c551, and b5 has been analyzed in terms of a monopole-dipole formalism (van Leeuwen, J.W. 1983. Biochim. Biophys. Acta. 743:408-421). The dipole moments of the reduced and oxidized forms of Ps. aeruginosa cytochrome c551 are 190 and 210 D, respectively (calculated from the crystal structure). The projections of these on the vector from the center of mass through the exposed heme edge are 120 and 150 D. For cytochrome b5, the dipole moments calculated from the crystal structure are 500 and 460 D for the reduced and oxidized protein; the projections of these dipole moments through the exposed heme edge are -330 and -280 D. A fit of the ionic strength dependence of the electron self-exchange rate constants gives -280 (reduced) and -250 (oxidized) D for the center of mass to heme edge vector. The self-exchange rate constants extrapolated to infinite ionic strength of cytochrome c, c551, and b5 are 5.1 x 10(5), 2 x 10(7), and 3.7 x 10(5) M-1 s-1, respectively. The extension of the monopole-dipole approach to other cytochrome-cytochrome electron transfer reactions is discussed. The control of electron transfer by the size and shape of the protein is investigated using a model which accounts for the distance of the heme from each of the surface atoms of the protein. These calculations indicate that the difference between the electrostatically corrected self-exchange rate constants of cytochromes c and c551 is due only in part to the different sizes and heme exposures of the two proteins.

Isolation and Structure Elucidation of Seco-neokadsuranic Acid A and 3,4-Seco-(24Z)-lanosta-4(30),8,24-triene-3,26-dioic Acid1

Seco-neokadsuranic acid A, the second natural triterpenoid with the unusual 14(13-->12) ABEO-lanostane skeleton was isolated from KADSURA HETEROCLITA together with 3,4-seco-(24 Z)-lanosta-4(30),8,24,triene-3,26-dioic acid. The present paper deals with the isolation and structure elucidation of these two new compounds and the preparation of two new 7-oxo-lanostane triterpenoid derivatives.

Isolation and Structure Elucidation of Neokadsuranic Acid A, the First Triterpenoid with the 14 (13-->12) abeo Lanostane Skeleton, and (24Z)-3-Oxo-lanosta-8,24-dien-26-oic Acid1

Neokadsuranic acid A, which is the first triterpenoid with the 14(13-->12) ABEO lanostane skeleton, was isolated from KADSURA HETEROCLITA together with (24 Z)-3-oxo-lanosta-8,24-dien-26-oic acid. The present paper deals with the isolation and structure elucidation of these two new compounds.

Triterpenoid Acids from Kadsura longipedunculata. Neokadsuranic Acids B and C: Two Novel Triterpenoids with 14 (13 --> 12)abeo-Lanostane Skeletons

Six triterpenoid acids were isolated from the stems of KADSURA LONGIPEDUNCULATA, collected in Kuangxi province. Four of them were new compounds and assigned as (24 Z)-3-oxo-12alpha-acetoxylanosta-8,24-dien-26-oic acid ( 1), (24 Z)-3-oxo-12alpha-hydroxylanosta-8,24-dien-26-oic acid ( 2), (24 Z)-3-oxo-14(13-->12) ABEO-lanosta-8,13(18),24-trien-26-oic acid ( 3), and (24 Z)-3-oxo-13beta-hydroxy-14(13-->12) ABEO-lanosta-8,24-dien-26-oic acid ( 4). Compounds 3 and 4 were named neokadsuranic acids B and C, respectively.

Visual field defects for unidirectional and oscillatory motion in depth

Visual fields for oscillatory motion in depth were recorded for 21 subjects. Near fields were different from far fields in 8 and similar in 11 subjects. Visual fields for unidirectional motion in depth were recorded for 16 subjects for near and far disparities. Some subjects had fields that differed for approaching versus receding motion in depth and/or for near versus far disparities. In particular, for near disparities, approaching versus receding motion gave fields that were different in 5 and similar 7 subjects; for far disparities, approaching versus receding motion gave fields that were different in 1 and similar in 10 subjects. For approaching motion in depth, near fields differed from far fields in 3 and were similar in 8 subjects; for receding motion in depth, near fields were different from far fields in 5 and similar in 8 subjects. Because sensitivity to monocular frontal plane motion showed no irregularities corresponding to the stereomotion field defects, we conclude that (1) stereomotion field defects were chiefly due to defective cortical processing of motion. We also conclude that (2) stereomotion field defects--at least for unidirectional motion--are caused by loss of sensitivity to unidirectional motion in depth rather than to abnormal interactions between mechanisms for approaching and receding motion, and (3) the finding of directional-specific stereomotion blindness is better explained by the two-population than by the one-population hypothesis of stereomotion blindness. We suggest that the substantial incidence of stereomotion field defects in normally-sighted subjects has implications for clinical studies and for visual assessment of pilots.

Henricine, a New Tetrahydrofuran Lignan from Schisandra henryi

A new tetrahydrofuran lignan, named henricine ( 1), was isolated from the stems of SCHISANDRA HENRYI. High resolution COSY spectrum was used in the structural elucidation.

Triterpenoids from Roots and Stems of Kadsura coccinea

24-Methylenecycloartenone ( 1), kadsuric acid ( 2) and a new triterpenoid acid named coccinic acid ( 3A) were isolated from the ether soluble fraction of the dried roots and stems of KADSURA COCCINEA.