Low serum thyroxine due to anti-thyroxine antibody

In one case of untreated Hashimoto's thyroiditis, the serum thyroxine (T4) value, obtained by radioimmunoassay (RIA) employing resin to separate bound and free T4, was significantly lower than that obtained by competitive protein binding analysis (CPBA). The discrepancy was found to be due to the presence of anti-thyroxine autoantibody in the serum. This phenomenon is considered to be of practical importance in interpreting the T4 value by RIA in cases with autoimmune thyroid diseases.     

Functional comparison of DCCD-sensitive Na+/H+ antiporter in Halobacterium halobium with monensin

Membrane vesicles from Halobacterium halobium create a large, inside negative membrane potential (delta psi) and small, inside alkaline pH gradient (delta pH) by illumination in 3 M NaCl. delta psi was the major component of a proton electrochemical potential (delta microH+) over a pH range from 5 to 8. After DCCD treatment of the vesicles, delta psi was replaced by delta pH due to the inhibition of the intrinsic delta pH----delta psi transformation process: delta psi formation in light is markedly retarded and an inversely large delta pH is established at these pHs. DCCD-caused changes in delta psi and delta pH were completely restored to the control level by the addition of monensin, an electroneutral Na+/H+ exchanger. The ratio of DCCD-caused change in delta pH and delta psi was identical to that of monensin-recovered delta psi and delta pH. The delta psi/delta pH ratio was approximately 0.8, that is, 100 mV of delta pH was transformed into 78 mV of delta psi. The present results indicate that the intrinsic activity of the DCCD-sensitive delta pH----delta psi transformation is mediated by an electroneutral Na+/H+ exchange.     

HPF1-dependent PARP activation promotes LIG3-XRCC1-mediated backup pathway of Okazaki fragment ligation

DNA ligase 1 (LIG1) is known as the major DNA ligase responsible for Okazaki fragment joining. Recent studies have implicated LIG3 complexed with XRCC1 as an alternative player in Okazaki fragment joining in cases where LIG1 is not functional, although the underlying mechanisms are largely unknown. Here, using a cell-free system derived from Xenopus egg extracts, we demonstrated the essential role of PARP1-HPF1 in LIG3-dependent Okazaki fragment joining. We found that Okazaki fragments were eventually ligated even in the absence of LIG1, employing in its place LIG3-XRCC1, which was recruited onto chromatin. Concomitantly, LIG1 deficiency induces ADP-ribosylation of histone H3 in a PARP1-HPF1-dependent manner. The depletion of PARP1 or HPF1 resulted in a failure to recruit LIG3 onto chromatin and a subsequent failure in Okazaki fragment joining in LIG1-depleted extracts. Importantly, Okazaki fragments were not ligated at all when LIG1 and XRCC1 were co-depleted. Our results suggest that a unique form of ADP-ribosylation signaling promotes the recruitment of LIG3 on chromatin and its mediation of Okazaki fragment joining as a backup system for LIG1 perturbation.     

Removal of troponin C and desensitization of myosin B from ascidian smooth muscle by treatment with ethylene diamine tetraacetate

On treatment with 10 mM EDTA at 30 degrees C, protein of 18,000 daltons was released from myofibrils, thin filaments and myosin B prepared from the smooth muscle of an ascidian, Halocynthia roretzi. This protein was purified from the EDTA extract of myofibrils by differential centrifugation, freeze-drying and gel-filtration. Based on its molecular weight, electrophoretic mobilities in the presence and absence of Ca2+ and other properties, it was identified as troponin C. By EDTA treatment, ascidian myosin B lost the Ca2+-sensitivity of Mg2+-ATPase, and EDTA-treated myosin B recovered the sensitivity by mixing with the EDTA extract of myosin B in the presence of Mg2+. Gel-electrophoretic patterns indicated that desensitization and resensitization of ascidian myosin B were accompanied by the removal and binding of troponin C. These results indicate that ascidian smooth muscle is regulated by a troponin-tropomyosin system, and desensitization induced by EDTA treatment is due to the removal of troponin C but not the release of the light chains of the myosin molecule. Based on these findings, we have established a simple method for the purification of troponin C from ascidian smooth muscle.     

The extensor and peroneal muscles of the crab-eating monkey (Macaca fascicularis)

On the basis of 60 hindlimbs of 30 crab-eating monkeys (Macaca fascicularis) of each sex, the morphology of the crural extensor and the peroneal group of leg muscles is described and some functional indices are calculated. For the attachments and measurements of the muscles, the results obtained in this study generally agreed with those of otherMacaca species. The crural extensor has minor differences. Some anomalous modes of insertion are observed in the peroneal group. These results indicate the phyletically labile state of the peronei in the crab-eating monkey.     

Antibiotic Treatment in Mice Infected with Japanese Borrelia garinii: Efficacy of Ceftriaxone for Eradicating the Infection Induced by Ixodes persulcatus Tick Bites

We compared the efficacy of three antibiotics (ceftriaxone, erythromycin and clarithromycin) against Borrelia garinii infection in mice. The nymphal ticks of Ixodes persulcatus infected with the strain JEM6 of Japanese B. garinii were allowed to feed on female C3H mice. The mice were treated with each of the antibiotics for 5 consecutive days 1, 3, or 7 weeks after tick detachment. The doses of antibiotics per day were as follows: 5 mg intraperitoneal injection of ceftriaxone, 2 mg intraperitoneal injection of erythromycin and 1 mg peroral administration of clarithromycin. The infection status in treated mice was monitored by culturing their earlobes, hearts and urinary bladders in BSK II medium. Ceftriaxone eliminated borreliae completely; however, a recurrence of infection was observed in mice treated with erythromycin and clarithromycin.     

SIN-1 cytotoxicity to PC12 cells is mediated by thiol-sensitive short-lived substances generated through SIN-1 decomposition in culture medium

As a generator of peroxynitrite (ONOO⁻), 3-morpholinosydnonimine (SIN-1) is widely used in the study of oxidative/nitrosative stress in cultured cells, although controversy exists regarding active species responsible for cytotoxicity. In this study, we report that unstable thiol-sensitive substances, generated from the reaction of SIN-1 with components in culture medium, play a crucial role in SIN-1 cytotoxicity in PC12 cells. Exposure of cells to culture medium obtained after almost complete SIN-1 decomposition at 37 °C for 2 h demonstrated almost the same degree of cytotoxicity as did fresh SIN-1. The cytotoxicity of SIN-1-decomposed medium largely depended on serum, decayed with time, and could be completely abolished by the addition of thiols. Degradation of synthetic ONOO⁻ in the culture medium did not reproduce the unstable cytotoxicity. The presence of superoxide dismutase (SOD) during SIN-1 decomposition prevented the formation of the cytotoxic substances, whereas SOD had no protection against the cytotoxicity itself, suggesting a crucial role of simultaneously generated superoxide and nitric oxide in the formation of the toxicants, but not in their cytotoxic action. The cytotoxicity of fresh SIN-1 is dramatically suppressed in a basal medium (Hanks balanced salt), suggesting that the cytotoxicity of fresh SIN-1 also requires components of culture medium. These results suggest that SIN-1 cytotoxicity in PC12 cells is mediated via the generation of cytotoxic substances in the medium during its decomposition.