Identification of the thromboxane A2 receptor in hepatic sinusoidal endothelial cells and its role in endotoxin-induced liver injury in rats

The presence of the thromboxane A2 receptor in sinusoidal endothelial cells was investigated and its pathogenic role in endotoxin-induced liver injury examined. The receptor was measured with a binding assay using a specific thromboxane A2 receptor antagonist, [3H]S-145. Scatchard analysis of the binding indicated the presence of a single class of high-affinity binding sites with a dissociation constant of 5.00 +/- 0.96 nmol/L, a maximal binding of 22.85 +/- 2.71 fmol/10(6) cells and 13.80 +/- 1.60 x 10(3) binding sites per cell. The addition of a cyclooxygenase inhibitor, indomethacin, during the cell preparation increased the maximal binding value and the number of binding sites of 37.34 +/- 3.01 and 22.50 +/- 1.80 x 10(3) sites/cell, respectively. The binding was displaced by various thromboxane A2 analogs such as ONO-3708 and STA2 but was not effectively competed for by other prostaglandins. Endotoxin injection reduced dissociation constant, maximal binding and the number of binding sites in sinusoidal endothelial cells to 3.49 +/- 0.87 nmol/L, 6.03 +/- 0.64 fmol/10(6) cells and 3.65 +/- 0.39 x 10(3) sites/cell, respectively. A cyclooxygenase inhibitor and a Kupffer cell inhibitor added before endotoxin treatment significantly prevented the reduction in the number of thromboxane A2 receptors. It is possible that these effects were due to a reduction in the agonist-induced internalization of the thromboxane A2 receptor brought about by the prevention of thromboxane A2 production. Preadministration of both a cyclooxygenase inhibitor and a thromboxane A2 receptor antagonist attenuated the degree of endotoxin-induced liver injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunologic activation of hepatic macrophages in septic rats: a possible mechanism of sepsis-associated liver injury

To investigate the pathogenesis of liver dysfunction accompanying intra-abdominal sepsis, we used rats with cecal ligation and punctures (CLP) and examined the expression of the inflammatory cytokines IL-1-alpha, IL-1-beta, and TNF-alpha, as well as the expression of a cell adhesion molecule, ICAM-1, in the liver. We also examined the expression of Ia antigen and interleukin-2 receptor (IL-2R) on hepatic macrophages. Hepatic macrophages isolated from rats 24 hours after CLP exhibited significantly higher IL-1 and TNF activity than those from control rats. Hepatic macrophages isolated from rats 72 hours after CLP exhibited the maximal IL-1 and TNF activity. In the hepatic nonparenchymal cells, IL-1-alpha mRNA was induced 1 hour after CLP, increasing to the maximal level 3 hours after CLP, whereas IL-1-beta mRNA was induced gradually, reaching a peak 6 hours after CLP. ICAM-1 mRNA reached a peak 3 hours after CLP. Induction of TNF-alpha mRNA was not detected by the present Northern blot analysis. Seventy-two hours after CLP, the proportions of hepatic macrophages expressing Ia antigens and IL-2R were increased significantly, as revealed by the flow cytometric analysis. In conclusion, the present study showed that hepatic macrophages are in an activated state in sepsis as indicated by their increased production of inflammatory monokines and their increased expression of immunomodulatory surface molecules. Further, we demonstrated the sequential induction of the mRNA of the various inflammatory cytokines and ICAM-1. These findings strengthen the notion that these cytokines are relevant to the pathogenesis of liver injury associated with sepsis.

Effect of PGE2 on interleukin-1 and superoxide release from primary-cultured human hepatic macrophages

In order to learn more about how human hepatic macrophages function, we analyzed the effect of exogenous PGE2 on the amounts of interleukin-1 (IL-1) and superoxide (O2-) released from primary-cultured human hepatic macrophages (HHM phi). When endogenous PGE2 production was blocked by indomethacin, exogenous PGE2 reduced IL-1 release from HHM phi in a dose-dependent manner, whereas it tended to increase O2- release from HHM phi. These results may suggest the probable contribution of PGE2 in regulating HHM phi mediator release in vivo.

[Study on the pulmonary tuberculosis in the elderly]

A study was made for 13 cases of patients over 80 years of age who received medical treatment for tuberculosis. Four factors of onset of tuberculosis at old age were indicated. 1. No opportunity for examination of X-ray for old generation. 2. Atypical shadows on the chest X-ray film. 3. Low stress tolerance. 4. Exacerbation of old tuberculosis during the treatment of other diseases. The results suggest the possibility of increasing pulmonary tuberculosis among the elderly persons in the near future.

[A case of invasive thymoma with pulmonary tuberculosis]

A 68-year old male was referred to our hospital for the treatment of pulmonary tuberculosis. Chest X-ray film revealed left diffuse pleural thickening. Treatment of pulmonary tuberculosis was started with streptomycin, isoniazid and rifampicin. Three months later, although smear and culture of the patient's sputum became negative for M. tuberculosis, he started to complain of dyspnea on exercise and left chest pain. Biopsies of a pleural tumor and a left subclavicular lymph node were done and a diagnosis of invasive thymoma with pleural dissemination and bone and lymph node metastasis was established. After three cycles of combination chemotherapy consisting of cyclophosphamide, adriamycin and vincristine, left chest pain disappeared and pleural thickening showed shrinkage.

Effects of the kallikrein-kinin system on phasic coronary vasospasm in dogs

It is well known that kinins are liberated from kininogen in blood during angina attack to maintain blood flow in coronary artery. We examined the effects of bradykinin, one of kinins, on the coronary artery other than vasodilation. The isolated canine coronary artery ring was suspended in gassed (95% O2, 5% CO2) Krebs-Henseleit buffer at 37 degrees C in vitro. The experimental phasic contraction of coronary artery was induced by 6 x 10(-4)M of 3,4-diaminopyridine which decreases K conductance (Y. Uchida, Jpn. Circ. J: 49, 128, 1985). The effect of bradykinin and other substances on the cycle length of contraction (CL), the peak tension of contraction phase (PT) and the tension during relaxation phase (RT) were observed. The phasic contraction was eliminated by 10(-7)M nifedipine and 10(-6)M diltiazem which block voltage dependent Ca channels. These Ca blockers reduced PT, but slightly increased CL, and weakly reduced RT. The phasic contraction was also eliminated by 10(-6)M bradykinin. However, bradykinin, unlike Ca blockers, did not reduce PT, but markedly prolonged CL and decreased RT significantly. This inhibition mode was very similar to those of nicorandil which increases K conductance. These data suggest that bradykinin plays a protective role in coronary vasospasm, and this antivasospasm effect may be mediated through the increase in K conductance.

[Long-term administration of tegafur in postoperative adjuvant chemotherapy in gastric cancer patients. Serial analysis of serum tegafur and 5-fluorouracil concentrations, and influence from PSK combination]

We investigated the pharmacokinetics of long-term (2-year) daily oral administration of FT-207-E or UFT for postoperative adjuvant chemotherapy in 85 gastric cancer patients by measuring serum FT-207 and 5-FU concentration serially. There were no significant changes in serum FT-207.5-FU concentration during observation period between FT-207-E and UFT groups. There was different operative modality between partial gastrectomy (Billroth I) and total gastrectomy, but no significant difference in serum FT-207.5-FU concentration between the two groups, and no significant serial changes in serum FT-207.5-FU concentrations were observed in both groups. Conversion from FT-207 to 5-FU measured by serum concentration was not suppressed by combination with the biological response modifier PSK.

New tetracycline resistance determinant on R plasmids from Vibrio anguillarum

Two classes of tetracycline resistance determinants on R plasmids were detected in Vibrio anguillarum strains isolated from ayu (sweat fish; Plecoglossus altivelis) farms in Japan. Tetracycline resistance genes categorized as class B were prevalent from 1973 to 1977; however, a new tetracycline resistance gene, which was not classified into tetracycline resistance determinant class A, B, C, or D, has been prevalent since 1981.

Effect of an immunopotentiator on Aeromonas salmonicida infection in rainbow trout (Salmo gairdneri)

The immunoactive peptide FK-565 (heptanoyl-y-D-glutamyl-(L)-mesodiaminopimelyl-(D)-alanine) was found to induce protection against intraperitoneal Aeromonas salmonicida infection in rainbow trout (Salmo gairdneri Richardson). The survival rate was as high as 60% when FK-565 was given intraperitoneally as a single dose (1mg/kg) one day before bacterial challenge. A non-specific stimulation of phagocytic cells by FK-565 at an early stage of the bacterial infection may contribute to the resistance observed. The phagocytic activity of peritoneal phagocytic cells as well as phagocytic cells of the pronephros were stimulated by FK-565 in vivo and in vitro, respectively, as compared to untreated control fish. Furthermore, decreased activity of phagocytic cells previously immunosuppressed with cyclophosphamide was rapidly restored by application of FK-565.

Protective efficacy of Aeromonas hydrophila vaccines in nile tilapia

Protection and serum antibody production against Aeromonas hydrophila was examined in nile tilapia, Tilapia nilotica (L.). Intraperitoneally injected formal in-killed and Freunds complete adjuvant vaccines were compared using different doses (2.9 X 10(7) and 2.9 X 10(9) cfu/ml). Upon challenge, the protective ability and antibody titers resulting were significantly different between vaccinated and unvaccinated groups. A relative level of protection of 100% was obtained within two-weeks, and a maximum level of 53-61% protection was found one-week post-vaccination.

Low doses of naloxone produce analgesia in the mouse brain by blocking presynaptic autoinhibition of enkephalin release

The involvement of presynaptic autoinhibition of Met-enkephalin release in naloxone-induced analgesia was studied. In both acetic acid writhing and tail-flick tests in mice, naloxone produced biphasic effects, analgesia at very low doses (1 microgram/kg s.c. or 1 ng intracisternal) and hyperalgesia at higher doses (100 micrograms/kg s.c. or 100 ng intracisternal). Morphine at 10(-6) to 10(-5)M depressed the high K+-evoked release of Met-enkephalin from slices of the rat brainstem by 12.5-55.9% of control, while naloxone at 10(-6)M significantly enhanced the release by 80.6%. These findings strongly suggest that in the mouse brain a very low dose of naloxone produces analgesia by blocking autoinhibition of enkephalin release.

Monoclonal antibodies to L-asparaginase

Five hybridomas secreting monoclonal antibody to E. coli L-asparaginase were isolated. These monoclonal antibodies were classified into 3 different subclasses; Ig G1 (1 clone), Ig G2 (2 clones) and Ig G3 (2 clones). One of them possessed anti-L-asparaginase neutralizing activity. Four antibodies examined demonstrated a linear Langmuir binding plot and binding affinities, with equilibrium dissociation constant (Kd) ranging between 2.5 X 10(-9) M and 6.3 X 10(-10) M. The monoclonal antibodies should be useful probes for investigation of the enzyme activity.

Drug resistance and R plasmids in Vibrio anguillarum isolated in cultured ayu (Plecoglossus altivelis)

Two hundred twenty-six strains of Vibrio anguillarum collected from cultured ayu ( Plecoglossus altivelis ) between 1978 and 1980 were studied for their sensitivities to 10 chemotherapeutics. In order to determine whether the drug-resistant strains possessed transferable R plasmids, they were conjugated with Escherichia coli. Almost all the strains isolated during the 3 years showed resistance to nalidixic acid (NA) and/or furazolidone (NF). NA and NF resistance were not transferred to Escherichia coli from any of the strains. Chloramphenicol-resistant strains were isolated in every year and almost all of them carried transferable R plasmids. Only one strain with tetracycline resistance was found among the strains tested. Strains resistant to sulfonamides, streptomycin, ampicillin (ABP), and trimethoprim (TMP) increased rapidly in 1980, and a large number of them carried transferable R plasmids. Transferable R plasmids encoded with resistance to ABP and TMP were detected for the first time in V. anguillarum strains. The R plasmids detected in the strains isolated in 1980 were classified into incompatibility groups E, A, and an untypable group. The R plasmid DNAs were cleaved by EcoRI to yield 11 to 13 fragments. The estimated molecular weights of the R plasmids from the five strains ranged from 97 to 104 M daltons.

Inhibition of erythrocyte ATPase activity by aclacinomycin and reverse effects of ascorbate on ATPase activity

We studied the effect of aclacinomycin on human erythrocyte membrane enzymes. Aclacinomycin inhibited ATPase, including Na-K-dependent ATPase, ouabain insensitive ATPase and Ca-ATPase. However acetylcholinesterase was not inhibited by aclacinomycin. The ATPase activities were not inhibited by aclacinomycin if ascorbate was added to the incubation mixture. However other reducing agents, alpha-tocopherol, superoxide dismutase and catalase had no effect on ATPase activity. Ascorbate may protect membrane proteins and lipids from peroxidate damage.