Changes Over 7 Years in Temperature Control Treatment and Outcomes After Out-of-Hospital Cardiac Arrest: A Japanese, Multicenter Cohort Study

Temperature control is the only neuroprotective intervention suggested in current international guidelines for patients with return of spontaneous circulation after cardiac arrest, but the prevalence of temperature control therapy, temperature settings, and outcomes have not been clearly reported. We aimed to investigate changes over 7 years in provision of temperature control treatment among out-of-hospital cardiac arrest (OHCA) patients in Kanto region, Japan. Data of all adult OHCA patients who survived for more than 24 hours in the prospective cohort studies, SOS-KANTO 2012 (conducted from 2012 to 2013) and SOS-KANTO 2017 (conducted from 2019 to 2021), in Japan were included. We compared the prevalence of temperature control and the proportion of mild (≥35°C) and moderate (from 32°C to 34.9°C) hypothermia between the two study groups. We also performed a Cox regression analysis to evaluate 30-day mortality adjusted by temperature control therapy (none, moderate hypothermia, or mild hypothermia), age, sex, past medical history, witnessed status, bystander cardiopulmonary resuscitation, initial rhythm, location of arrest, and dataset (SOS-KANTO 2012 or 2017). We analyzed data from 2936 patients (n = 1710, SOS-KANTO 2012; n = 1226, SOS-KANTO 2017). Use of temperature control was lower (45.3% vs. 41.4%, p = 0.04), moderate hypothermia was lower (p < 0.01), and mild hypothermia was higher (p < 0.01) in SOS-KANTO 2017 compared with SOS-KANTO 2012. The survival rate was significantly higher for patients with mild (p < 0.01) and moderate (p < 0.01) hypothermia compared with those who did not receive temperature control therapy. Overall, the incidence of moderate hypothermia decreased and that of mild hypothermia increased and the use of temperature control decreased between the two studies conducted 7 years apart in the Kanto area, Japan. Temperature control management might improve survival of patients with OHCA.

Impact of the COVID-19 pandemic on prehospital and in-hospital treatment and outcomes of patients after out-of-hospital cardiac arrest: a Japanese multicenter cohort study

BACKGROUND

In the chain of survival for Out-of-hospital cardiac arrest (OHCA), each component of care contributes to improve the prognosis of the patient with OHCA. The SARS-CoV-2 (COVID-19) pandemic potentially affected each part of care in the chain of survival. The aim of this study was to compare prehospital care, in-hospital treatment, and outcomes among OHCA patients before and after the COVID-19 pandemic.

METHODS

We analyzed data from a multicenter prospective study in Kanto area, Japan, named SOS-KANTO 2017. We enrolled patients who registered during the pre-pandemic period (September 2019 to December 2019) and the post-pandemic period (June 2020 to March 2021). The main outcome measures were 30-day mortality and the proportion of favorable outcomes at 1 month, and secondary outcome measures were changes in prehospital and in-hospital treatments between the pre- and post-pandemic periods.

RESULTS

There were 2015 patients in the pre-pandemic group, and 5023 in the post-pandemic group. The proportion of advanced airway management by emergency medical service (EMS) increased (p < 0.01), and EMS call-to-hospital time was prolonged (p < 0.01) in the post- versus pre-pandemic group. There were no differences between the groups in defibrillation, extracorporeal membrane oxygenation, or temperature control therapy (p = 0.43, p = 0.14, and p = 0.16, respectively). Survival rate at 1 month and favorable outcome rate at 1 month were lower (p = 0.01 and p < 0.01, respectively) in the post- versus pre-pandemic group.

CONCLUSION

Survival rate and favorable outcome rate 1 month after return of spontaneous circulation of OHCA worsened, EMS response time was prolonged, and advanced airway management by EMS increased in the post- versus pre-pandemic group; however, most prehospital and in-hospital management did not change between pre- and post-COVID-19 pandemic.

Risk factors for the need for advanced care among prescription and over-the-counter drug overdose patients

Aim

Prescription drug and over-the-counter (OTC) drug overdose is a major problem in emergency departments in Japan, and some need advanced care which is more than observation. We aimed to identify the prehospital risk factors for the need of advanced care among overdose patients.

Methods

This was a single-center retrospective cohort study. We included overdoses patients of prescription drugs or OTC drugs, who admitted to our hospital between 2016 and 2021. We grouped them into advanced care and non-advanced care. The main outcome was the need for advanced care. We performed a multiple logistic regression analysis, calculated the PAV score (Paracetamol use, Alcohol use, abnormal Vital signs on scene) and performed a receiver operating characteristic (ROC) analysis.

Results

There were 229 subjects. The logistic regression analysis revealed that alcohol, paracetamol, and the abnormal vital signs on scene were associated with advanced care (alcohol-odds ratio [OR]: 2.95; 95% confidence interval [CI]: 1.29-6.75; paracetamol-OR: 5.47; 95% CI: 2.18-13.71; abnormal vital signs-OR: 4.61, 95% CI: 2.07-10.27). The rate of advanced care in the high PAV score (2 and 3) group was statistically higher than that in the low PAV score (0-1) group (p = 0.04). Area under the ROC curve of the PAV score was 0.72 (95% CI, 0.65-0.80).

Conclusion

Alcohol, paracetamol use and abnormal vital signs on scene might be risk factors for advanced care among prescription drugs or OTC drugs overdose patients, and the PAV score may predict the need for advanced care.

Evaluation of clinical response to empirical antimicrobial therapy on day 7 and mortality in the intensive care unit: sub-analysis of the DIANA study Japanese data

It is not clear whether evaluating the clinical response to antibiotic use at day 7 among critically ill patients accurately predicts outcomes. We aimed to evaluate the relationship between clinical response to the initial empiric therapy on day 7 and mortality.

Methods

The determinants of antimicrobial use and de-escalation in critical care (DIANA) study was an international, multicenter, observational study on antibiotic use in the intensive care unit (ICU). ICU patients ages over 18 years in whom an empiric antimicrobial regimen in Japan was initiated were included. We compared patients who were evaluated as cured or improved ("effective") 7 days after starting antibiotic treatment with patients who were evaluated as deteriorated ("failure").

Results

Overall, 217 (83%) patients were in the effective group, and 45 (17%) were in the failure group. Both the infection-related mortality rate in the ICU and the in-hospital infection-related mortality rate in the effective group were lower than those in the failure group (0% versus 24.4%; P < 0.01 and 0.5% versus 28.9%; P < 0.01, respectively).

Conclusion

Assessment of efficacy of empiric antimicrobial treatment on day 7 may predict a favorable outcome among patients suffering from infection in the ICU.

Utility of a Compatibility Chart for Continuous Infusions in the Intensive Care Unit

BACKGROUND

In the intensive care unit (ICU), multiple intravenous drugs are often administered through the same catheter line, greatly increasing the risk of drug incompatibility. We previously developed a compatibility chart including 27 drugs and have used it to avoid drug incompatibilities in the ICU. This retrospective study evaluated the utility of this chart by analyzing prescriptions and incidents of incompatibilities in an ICU.

METHODS

We analyzed 257 ICU prescriptions of two or more continuous infusions on the same day during the period between March 2016 and February 2017 and investigated the rate of compliance with the compatibility chart. Drug combinations were classified as "compatible," "tolerable compatible," "incompatible," and "no data." For all combinations, the compliance rate was defined as the ratio of compatible and tolerable compatible combinations. Additionally, using our hospital incident report database, we analyzed 27,117 injections administered in the ICU between March 2016 and February 2017 and investigated incidents related to incompatibility.

RESULTS

Three hundred infusion combinations were identified in the prescriptions. The compliance rate was 97% (n = 293). Of the 113 combinations judged to be tolerable compatible, 98% (n = 111) consisted of three or more continuous medications injected through the same intravenous line. Of the two incidents related to incompatibility in the incident report database, the combination "nicardipine and furosemide" was defined as incompatible in the compatibility chart.

CONCLUSIONS

The high rate of compliance with the compatibility chart suggested it was useful in preventing drug incompatibility.

Association between mortality and age among mechanically ventilated COVID-19 patients: a Japanese nationwide COVID-19 database study

Background

Only a few studies have reported the association between age and mortality in COVID-19 patients who require invasive mechanical ventilation (IMV). We aimed to evaluate the effect of age on COVID-19-related mortality among patients undergoing IMV therapy.

Methods

This cohort study was conducted using the COVID-19 Registry Japan database, a nationwide multi-centre study of hospitalized patients with laboratory-confirmed COVID-19. Of all 33,808 cases registered between 1 January 2020 to 28 February 2021, we analysed 1555 patients who had undergone IMV. We evaluated mortality rates between age groups using multivariable regression analysis after adjusting for known potential components, such as within-hospital clustering, comorbidities, steroid use, medication for COVID-19, and vital signs on admission, using generalized estimation equation.

Results

By age group, the mortality rates in the IMV group were 8.6%, 20.7%, 34.9%, 49.7% and 83.3% for patients in their 50s, 60s, 70s, 80s, and 90s, respectively. Multivariable analysis showed that compared with those for patients aged < 60 years, the odds ratios (95% confidence interval) of death were 2.6 (1.6–4.1), 6.9 (4.2–11.3), 13.2 (7.2–24.1), 92.6 (16.7–515.0) for patients in their 60s, 70s, 80s, and 90s, respectively.

Conclusions

In this cohort study, age had a great effect on mortality in COVID-19 patients undergoing IMV, after adjusting for variables independently associated with mortality. This study suggested that age was associated with higher mortality and that preventing progression to severe COVID-19 in elderly patients may be a great public health issue.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00959-6.

Blood concentration of levetiracetam after bolus administration in patients with status epilepticus

PURPOSE

We aimed to evaluate the blood concentration of levetiracetam (LEV), as a second-line drug, in patients with status epilepticus (SE) in an emergency clinical setting.

METHODS

We prospectively evaluated 20 consecutive patients with SE admitted to our department between July 2017 and July 2019. LEV (2500 mg) was administered via bolus infusion after diazepam infusion, followed by 500 mg every 12 h for 48 h and then 500 mg orally. The primary outcomes were LEV blood concentration 15 min, 12 h, 48 h, and 96 h after administration and the proportion of patients showing trough LEV concentration within the therapeutic range. The secondary outcomes were the discontinuation of apparent convulsive seizure, epileptic wave on electroencephalogram, tracheal intubation, adverse events related to blood parameters, and abnormal findings in vital signs examination.

RESULTS

Median blood LEV (2500 mg) concentration at 15 min after administration was 81.6 μg/mL. The median trough concentration after 12, 48, and 96 h was 28.8, 10.5, and 9.1 μg/mL, respectively. Moreover, 95% of patients had trough concentration above the lower limit of the therapeutic blood concentration (>12 μg/mL) after 12 h. Regarding secondary outcomes, endotracheal intubation, seizure suppression, and abnormal electroencephalogram findings were observed in approximately 40%, 90%-95%, and 41% of patients, respectively. No abnormal findings were noted in blood tests and vital sign examination, although the AST/ALT levels increased in 10% of the patients.

CONCLUSION

After bolus administration of 2500 mg, the blood LEV concentration reached the therapeutic window in patients with early-stage SE.

Early versus late surgery after cervical spinal cord injury: a Japanese nationwide trauma database study

BACKGROUND

The management of cervical spinal cord injury (SCI) has changed drastically in the last decades, and surgery is the primary treatment. However, the optimum timing of early surgical treatment (within 24 h or 72 h after injury) is still controversial. We sought to determine the optimum timing of surgery for cervical SCI, comparing the length of the intensive care unit (ICU) stay and in-hospital mortality in patients who underwent surgical treatments (decompression and stabilization) for cervical SCI within 24 h after injury and within 7 days after injury.

METHODS

This was a retrospective cohort study using Japan Trauma Data Bank (JTDB) which is a nationwide, multicenter database. We selected adult isolated cervical SCI patients who underwent operative management within 7 days after injury, between 2004 and 2015. The main outcome measures were the length of ICU stay and in-hospital mortality. We grouped the patients into two, based on the time from onset of injury to surgery, an early group (within 24 h) and a late group (from 25 h to 7 days). Next, we performed multivariable analyses for analyzing the relevance between the timing of surgery and the length of ICU stay after adjusting for baseline characteristics using propensity score. We also performed the Cox survival analyses to evaluate in-hospital mortality.

RESULTS

From 236,698 trauma patients registered in JTDB, we analyzed 514 patients. The early group comprised 291 patients (56.6%), and the late group comprised 223 (43.4%). The length of ICU stay did not differ between the two groups (early, 10 days; late, 11 days; p = 0.29). There was no significant difference for length of ICU stay between the early and late group even after adjustment by multivariate analysis (p = 0.64). There was no significant difference in in-hospital mortality between the two groups (the early group 3.8%, the late group 2.2%, p = 0.32), and no significant difference was found in the Cox survival analysis.

CONCLUSIONS

Our study showed that neither the length of ICU stay nor in-hospital mortality after spinal column stabilization or spinal cord decompression for cervical SCI significantly differed according to the timing of surgery between 24 h and 7 days.

Amiodarone Compared with Lidocaine for Out-Of-Hospital Cardiac Arrest with Refractory Ventricular Fibrillation on Hospital Arrival: a Nationwide Database Study

PURPOSE

The latest resuscitation guidelines recommend the use of amiodarone in adult patients with out-of-hospital cardiac arrest (OHCA) and refractory ventricular fibrillation (VF) to improve the rates of return of spontaneous circulation. However, there is limited evidence to suggest that amiodarone is superior to lidocaine with respect to survival at discharge. The purpose of the present study was to evaluate the hypothesis that amiodarone is superior to lidocaine with regard to the rate of survival to hospital discharge for OHCA patients with VF/pulseless VT (pVT) on hospital arrival.

METHODS

Using the Japanese Diagnosis Procedure Combination inpatient database, we identified 3951 patients from 795 hospitals who experienced cardiogenic OHCA and had refractory ventricular fibrillation on hospital arrival between July 2007 and March 2013. The patients were categorized into amiodarone (n = 1743) and lidocaine (n = 2208) groups, from which 801 propensity score-matched pairs were generated.

RESULTS

There was no significant difference in the rate of survival to hospital discharge between the amiodarone and lidocaine groups (15.2 % vs. 17.1 %; difference, -1.9 %; 95 % CI, -5.5 to 1.7) in propensity score-matched analyses. Cox regression analyses did not indicate significant in-hospital mortality differences between the amiodarone and lidocaine groups for the propensity score-matched groups (hazard ratio, 1.05; 95 % CI, 0.94 to 1.17).

CONCLUSIONS

The present nationwide study suggested that there was no significant difference in the rate of survival to hospital discharge between cardiogenic OHCA patients with persistent ventricular fibrillation on hospital arrival treated with amiodarone or lidocaine.

Early antibiotics administration during targeted temperature management after out-of-hospital cardiac arrest: a nationwide database study

Background

Patients resuscitated after cardiac arrest are reportedly at high risk for infection and sepsis, especially those treated with targeted temperature management (TTM). There is, however, limited evidence suggesting that early antibiotic use improves patient outcomes. We examined the hypothesis that early treatment with antibiotics reduces mortality in patients with cardiac arrest receiving TTM.

Methods

We identified 2803 patients with cardiogenic out-of-hospital cardiac arrest (OHCA) that were treated with TTM and were admitted to 371 hospitals that contribute to the Japanese Diagnosis Procedure Combination inpatient database between July 2007 and March 2013. Of these, 1272 received antibiotics within the first 2 days (antibiotics) and 1531 did not (control). We generated 802 propensity score-matched pairs.

Results

There was no significant difference in 30-day mortality between the groups (control vs. antibiotics; 33.0 % vs. 29.9 %; difference, 3.1 %; 95 % confidence interval [CI], −1.4 to 7.7 %, p = 0.18). Analysis using the hospital antibiotics prescribing rate as an instrumental variable showed that antibiotic use was not significantly associated with a reduction in 30-day mortality (6.6 %, CI 95 %, −0.5 to 13.7 %, p = 0.28). A subgroup analysis of patients who required extracorporeal membrane oxygenation (ECMO) indicated a significant difference in 30-day mortality between the 2 groups (62.9 % vs. 43.5 %; difference 19.3 %, CI 95 %, 5.9 to 32.7 %, p = 0.005). In the instrumental variable model, the estimated reduction in 30-day mortality associated with antibiotics was 18.2 % (CI 95 %, 21.3 to 34.4 %, p = 0.03) in ECMO patients.

Conclusions

Although there was no significant association between the use of antibiotics and mortality after overall cardiogenic OHCA treated with TTM, antibiotics may be beneficial in patients who require ECMO.

Double heterojunction nanowire photocatalysts for hydrogen generation

Charge separation and charge transfer across interfaces are key aspects in the design of efficient photocatalysts for solar energy conversion. In this study, we investigate the hydrogen generating capabilities and underlying photophysics of nanostructured photocatalysts based on CdSe nanowires (NWs). Systems studied include CdSe, CdSe/CdS core/shell nanowires and their Pt nanoparticle-decorated counterparts. Femtosecond transient differential absorption measurements reveal how semiconductor/semiconductor and metal/semiconductor heterojunctions affect the charge separation and hydrogen generation efficiencies of these hybrid photocatalysts. In turn, we unravel the role of surface passivation, charge separation at semiconductor interfaces and charge transfer to metal co-catalysts in determining photocatalytic H2 generation efficiencies. This allows us to rationalize why Pt nanoparticle decorated CdSe/CdS NWs, a double heterojunction system, performs best with H2 generation rates of ∼434.29 ± 27.40 μmol h(-1) g(-1) under UV/Visible irradiation. In particular, we conclude that the CdS shell of this double heterojunction system serves two purposes. The first is to passivate CdSe NW surface defects, leading to long-lived charges at the CdSe/CdS interface capable of carrying out reduction chemistries. Upon photoexcitation, we also find that CdS selectively injects charges into Pt NPs, enabling simultaneous reduction chemistries at the Pt NP/solvent interface. Pt nanoparticle decorated CdSe/CdS NWs thus enable reduction chemistries at not one, but rather two interfaces, taking advantage of each junction's optimal catalytic activities.

Supercontinuum spatial modulation spectroscopy: detection and noise limitations

Supercontinuum spatial modulation spectroscopy is a facile tool for conducting single molecule/particle extinction spectroscopy throughout the visible and near infrared (420-1100 nm). The technique's capabilities are benchmarked using individual Au nanoparticles (NPs) as a standard since they are well studied and display a prominent plasmon resonance in the visible. Extinction spectra of individual Au NPs with diameters (d) ranging from d ~ 8 to 40 nm are resolved with extinction cross sections (σ(ext)) of σ(ext) ~ 1 × 10(-13)-1 × 10(-11) cm(2). Corresponding signal-to-noise ratios range from ~30 to ~1400. The technique's limit of detection is determined to be 4.3 × 10(-14) cm(2) (4.3 nm(2)). To showcase supercontinuum spatial modulation spectroscopy's broader applicability, extinction spectra are acquired for other model systems, such as individual single-walled carbon nanotubes (SWCNTs) and CdSe nanowires. We show for the first time extinction spectra of individual (8,3) and (6,5) SWCNTs. For both chiralities, their E11 [(8,3) 1.30 eV (952 nm); (6,5) 1.26 eV (986 nm)] and E22 [(8,3) 1.86 eV (667 nm); (6,5) 2.19 eV (567 nm)] excitonic resonances are seen with corresponding cross sections of σ(ext) ~ 10(-13) cm(2) μm(-1).

Fasudil, a Rho-kinase inhibitor, attenuates lipopolysaccharide-induced vascular hyperpermeability and colonic muscle relaxation in guinea pigs

BACKGROUND

Rho-associated coiled coil-forming protein kinase (Rho-kinase), a downstream target effector of the small GTP-binding protein Rho, plays a key role in cell adhesion, motility, and contraction. The goal of the present study was to determine the role of the Rho/Rho-kinase signal pathway in the pathogenesis of lipopolysaccharide (LPS)-induced vascular hyperpermeability using the Rho-kinase inhibitor fasudil.

METHODS

To evaluate plasma leakage, fasudil (3 or 10 mg/kg) or saline was intravenously administered 30 min before LPS injection. LPS (100, 300, and 1,000 μg/0.1 mL/site) and saline (0.1 mL/site) were administered intracutaneously in the dorsum of guinea pigs. Vascular permeability was measured on the dorsal skin by the local accumulation of Evans Blue dye after intracutaneous injection of LPS (100-1000 μg/site) from Escherichia coli. For the measurement of colonic muscle tension, fasudil (3 mg/kg) or saline was intravenously administered 30 min before LPS injection. LPS (1 mg/kg) was administered intravenously.

RESULTS

Dye leakage in the skin increased significantly 2 h after the injection of LPS. This LPS-induced dye leakage was significantly suppressed by fasudil (3 and 10 mg/kg). LPS caused a transient decrease in colonic muscle tension, which peaked 2.5 h after the injection. This decrease in muscle tension was significantly suppressed by pretreatment with fasudil (3 mg/kg).

CONCLUSIONS

The Rho/Rho-kinase pathway might play an important role in the pathogenesis of LPS-induced endotoxemia, and fasudil could attenuate LPS-induced microvascular permeability, leading to inhibition of endotoxemia.

The Band Edge Luminescence of Surface Modified CdSe Nanocrystallites

We study the band edge luminescence of CdSe nanocrystallites to determine the origin of this emission. Previous studies have attributed the band edge emission to the recombination of photo-generated carriers trapped in localized surface states. Recently a number of “dark exciton” theories have been proposed which explain the luminescence in terms of recombination through internal core states. To address this issue we modify the surface of CdSe nanocrystallites with a number of organic/inorganic ligands and monitor the effect this has on the energetics of the resonant and non-resonant band edge luminescence. Our results for nanocrystallites passivated with trioctylphosphine oxide (TOPO), ZnS, 4-Picoline, 4-(trifluoromethyl)thiophenol, and tris(2-ethylhexyl)phosphate are in agreement with a dark exciton description of the band edge luminescence.

Surface Derivatization of Nanocrystalline CdSe Semiconductors

CdSe quantum dots (QDs) with several different ligands were prepared by ligand exchange reactions of trioctylphosphine oxide (TOPO)/trioctylphosphine selenide (TOPSe) passivated QDs with an excess of new ligands, such as pyridine, 4-picoline, thiophenol, 4-(trifluoromethyl)-thiophenol, and tris(2-ethylhexyl)phosphate. We find that 85–90% of ligands passivating the surface of the QDs are the newly introduced capping species and 10–15% are native TOPO/TOPSe ligands, reflecting the incomplete exchange of the QD surface. Thermal gravimetric analysis (TGA) and quantitative proton NMR measurements show that on average only 30% of surface cadmium atoms are passivated by TOPO/TOPSe. Approximately 1/3 of these native ligands occupy sites too strongly bound to be replaced by ligand exchange reactions.

Photoluminescent Mn-Doped ZNS Nanoclusters Synthesized within Block Copolymer Nanoreactors

Mn-doped ZnS nanoclusters were synthesized within microphase-separated films of diblock copolymers containing carboxylic acid units on one of the blocks. Zinc was selectively sequestered into the acid-containing domains by treating the films with diethylzinc or an aqueous zinc acetate solution. Manganese was loaded by subsequent treatment of the films with aqueous manganese acetate solutions. The manganese ions displaced a fraction of the zinc ions, and the extent of loading was controlled by varying the loading time, and the concentration of the manganese acetate solution. The extent of loading was tracked using ICP discharge emission spectroscopy. The doped nanoclusters were formed by subsequent treatment with H2S. The size of the doped ZnS nanoclusters could be varied by carrying out the H2S exposure in the presence of a coordinating base. Photoluminescence measurements revealed that the doped nanoclusters were photoluminescent, and showed the characteristic manganese emission. The universal doped cluster synthesis scheme used is quite general and can be easily modified to produce other doped nanocluster clusters, such as Tb-doped ZnS, or Mn-doped CdS.

The novel selective toll-like receptor 4 signal transduction inhibitor tak-242 prevents endotoxaemia in conscious Guinea-pigs

1. TAK-242 is a novel compound that suppresses nitric oxide and cytokine production by selectively inhibiting intracellular signals from toll-like receptor (TLR)-4. In the present study, we investigated the effectiveness of TAK-242 against sepsis using an endotoxaemia model in conscious and unrestricted guinea-pigs. Measures examined included muscle tension paralysis of the intestine, blood pressure, high morbidity group box (HMGB)-1 levels and survival rate. 2. Tension of the longitudinal muscle of the colon was monitored continuously by telemetry. Arterial blood pressure was monitored via a carotid artery catheter. TAK-242 was administered intravenously through a jugular vein catheter. Guinea-pigs were divided into a control group, given vehicle (placebo emulsion), and the experimental group, administered 3 or 10 mg/kg TAK-242, 1 h before administration of 10 mg/kg lipopolysaccharide (LPS). 3. In the control group, the tension of the longitudinal muscle of the colon decreased in a time-dependent manner and blood pressure was reduced, with maximal effects observed 1-3 h after administration of LPS. In the TAK-242-treated group, LPS-induced relaxation of the intestine and hypotension were significantly inhibited. In the control group, HMGB-1 levels were increased after LPS administration and this reaction was significantly blocked in the TAK-242-treated group. Importantly, survival rate was increased after TAK-242 treatment. 4. In conlusion, the results of the present study show that TAK-242 inhibited the symptoms associated with endotoxaemia in a guinea-pig model of sepsis and that it may, therefore, be an effective treatment for sepsis.

Identification of differentially expressed transcripts in bovine rumen and abomasum using a differential display method

The rumen has several important physiological functions: absorption, transport, metabolic activity, and protection. To clarify the molecular basis underlying the physiological function of the rumen, reticulum, omasum, and abomasum, we used mRNA differential display to isolate and identify differentially expressed genes in these tissues. We isolated 18 transcripts that coexpressed in the rumen, reticulum, and omasum. Five genes, ribosomal protein 19 (RPS19), basic helix-loop-helix domain containing class B2 (BHLHB2), NADH dehydrogenase flavoprotein 2 (NDUFV2), exosome component 9 (EXOSC9), and ribosomal protein 23 (RPS23), were highly expressed in the rumen of adult Holstein and Japanese Black cattle. Significant differences of expression were observed in the abomasum compared with the rumen, reticulum, and omasum. To investigate the expression pattern of these genes during the neonatal growth stage, the relative levels of gene expression were analyzed in the rumen and abomasum of 3-wk-, 13-wk-, and 18- to 20-mo-old Holstein cattle. The expression level of RPS19 did not change with age in the rumen and abomasum. The levels of BHLHB2, NDUFV2, and EXOSC9 mRNA in the abomasum decreased (P < 0.05) after weaning and declined (P < 0.05) further in adults; in contrast, expression in the rumen was not altered. Interestingly, the levels of RPS23 mRNA in the rumen increased (P < 0.05) after weaning and further increased in the adult; however, the level of expression of this gene decreased (P < 0.05) in the abomasum with weaning and age. This indicates that the 4 tissues, especially the rumen and abomasum, have different developmental pathways after birth and subsequent onset of rumination.

Photon Counting Statistics for Blinking CdSe−ZnS Quantum Dots: A Lévy Walk Process

We analyze photon statistics of blinking CdSe-ZnS nanocrystals interacting with a continuous wave laser field, showing that the process is described by a ballistic Lévy walk. In particular, we show that Mandel's Q parameter, describing the fluctuations of the photon counts, is increasing with time even in the limit of long time. This behavior is in agreement with the theory of Silbey and co-workers (Jung et al. Chem. Phys. 2002, 284, 181), and in contrast to all existing examples where Q approaches a constant, independent of time in the long time limit. We then analyze the distribution of the time averaged intensities, showing that they exhibit a nonergodic behavior, namely, the time averages remain random even in the limit of a long measurement time. In particular, the distribution of occupation times in the on-state compares favorably to a theory of weak ergodicity breaking of blinking nanocrystals. We show how our data analysis yields information on the amplitudes of power-law decaying on and off time distributions, information not available using standard data analysis of on and off time histograms. Photon statistics reveals fluctuations in the intensity of the bright state indicating that it is composed of several states. Photon statistics exhibits a Lévy walk behavior also when an ensemble of 100 dots is investigated, indicating that the strange kinetics can be observed already at the level of small ensembles.

Na+ dependence of extracellular Ca2+-sensing mechanisms leading to activation of an outwardly rectifying Cl- channel in murine osteoclasts

An elevation in the extracellular Ca(2+) concentration ([Ca(2+)](o)) is a key signal for bone remodeling by inhibiting the resorbing activity of osteoclasts. The [Ca(2+)](o)-sensing responses include a variety of morphological and functional changes, but the underlying mechanisms are yet to be defined. This study was aimed at investigating the [Ca(2+)](o)-sensing mechanisms leading to the activation of the Cl(-) channel in murine osteoclasts. A rise in either Ca(2+) or Gd(3+) activated an outwardly rectifying Cl(-) (OR(cl)) channel reversibly and dose-dependently, which was characterized by rapid activation kinetics, little inactivation, and blockage by DIDS. The concentration required for a half-maximal response was estimated to be >20-30 mmol/L for Ca(2+). Intracellular dialysis with an ATP-free pipette solution or application of an actin destabilizer, cytochalasin D, decreased the [Ca(2+)](o)-activated OR(cl) current. Substitution of extracellular Na(+) by an impermeable cation, N-methyl-D-glucamine(+), inhibited the [Ca(2+)](o)-activated OR(cl) channel, suggesting that the activation depended on extracellular Na(+). A blocker for the Na(+)-Ca(2+) exchanger, 2'4'-dichlorobenzamil hydrochloride (DCB), inhibited the [Ca(2+)](o)-activated OR(cl) channel as well. Although 10 mmol/L Ca(2+) activated the OR(cl) current only slightly at a standard intracellular pH (7.3), decreasing pH by dialyzing cells with an acidic pipette solution (pH 6.6) enhanced the [Ca(2+)](o)-activated OR(cl) current. This potentiation by cell acidosis was eliminated by amiloride, a blocker for the Na(+)-H(+) exchanger. Zinc ion (0.1 mmol/L) and a polycation, neomycin (0.2 mmol/L), activated the OR(cl) current at intracellular pH 6.6, whereas the effects of those cations were negligible at intracellular pH 7.3. These results suggest that [Ca(2+)](o)-sensing mechanisms, leading to activation of the OR(cl) channel in murine osteoclasts, are regulated by ATP and actin cytoskeletal organization, and are sensitized greatly by cell acidosis. Contributions of Na(+)-dependent transporters in this activating process are examined in the context of a possible intermediate signal of cell swelling caused by Na(+) influx.

In vitro and in vivo activities of anti-influenza virus compound T-705

T-705 (6-fluoro-3-hydroxy-2-pyrazinecarboxamide) has been found to have potent and selective inhibitory activity against influenza virus. In an in vitro plaque reduction assay, T-705 showed potent inhibitory activity against influenza A, B, and C viruses, with 50% inhibitory concentrations (IC(50)s) of 0.013 to 0.48 microg/ml, while it showed no cytotoxicity at concentrations up to 1,000 microg/ml in Madin-Darby canine kidney cells. The selectivity index for influenza virus was more than 2,000. It was also active against a neuraminidase inhibitor-resistant virus and some amantadine-resistant viruses. T-705 showed weak activity against non-influenza virus RNA viruses, with the IC(50)s being higher for non-influenza virus RNA viruses than for influenza virus, and it had no activity against DNA viruses. Orally administered T-705 at 100 mg/kg of body weight/day (four times a day) for 5 days significantly reduced the mean pulmonary virus yields and the rate of mortality in mice infected with influenza virus A/PR/8/34 (3 x 10(2) PFU). These results suggest that T-705 may be a compound that is useful and highly selective against influenza virus infections and that has a mode of action different from those of commercially available drugs, such as amantadine, rimantadine, and neuraminidase inhibitors.

Disruption of the p16/cyclin D1/retinoblastoma protein pathway in the majority of human hepatocellular carcinomas

p16, cyclin D1 and retinoblastoma protein (pRB) regulate G1 to S transition and are commonly targeted in various cancers. However, few studies have simultaneously examined all components of the p16/cyclin D1/pRB pathway (RB pathway) in hepatocellular carcinoma (HCC). To clarify the role of the disruption of the RB pathway in HCC, we analyzed p16, pRB and cyclin D1 in 47 HCCs. Inactivation of p16 was detected in 30 of 47 HCCs (64%) by Western blot analysis and significantly correlated with hypermethylation of the promoter of this gene. pRB expression was found to be absent in 13 of 47 HCCs (28%) by immunohistochemistry. We found that 38 of 47 HCCs (81%) contained at least one inactivation in either pRB or p16. Furthermore, there was a significant inverse correlation between p16 and pRB inactivation (p = 0.041). Overexpression of cyclin D1 was detected in 5 of 47 HCCs (11%) by immunohistochemistry. The cases with cyclin D1 overexpression exhibited an advanced clinicopathological appearance and also contained inactivation of pRB and/or p16. These findings suggest that inactivation of pRB and/or p16 is a major event in human hepatocarcinogenesis, while cyclin D1 overexpression may confer additional growth advantages to the tumor in addition to pRB and/or p16 inactivation in HCC.

Post-cultured development of basic electrophysiological properties of spinal neurons obtained from rat embryo

Basic electrical profiles of cultured neurons are modified by multiple factors, such as cell growth, differentiation and cell damage from the isolation procedure. In the present study, we assessed development of electrophysiological properties of rat spinal neurons over the late embryonic and early postnatal period in a neuron-enriched culture. After recovery from acute damage within 2 days after plating, the input conductance and amplitudes of voltage-gated Na(+) and K(+) currents increased parallel to the increase in the cell capacitance. Whether this depended on the period or the growth of the cell area was estimated by normalizing the parameters with the cell capacitance. The input conductance per unit area, the membrane time constant and the Na(+) current density remained constant for two weeks. However, densities of two types of outward K(+) currents, an A-current and a delayed rectifier, required 3--5 days to reach the maximum, although neither thresholds for activation nor sensitivities to blockers (TEA and 4AP) altered. The hyperpolarizing shift of the resting membrane potential became stabilized within 6--8 days, suggesting that the development of the K(+) currents underlay the shift. These results show that passive electrical properties and voltage-gated currents of rat spinal neurons in the neuron-rich culture differ in temporal patterns of development but stabilize at the latest within a week, corresponding to the day of birth.

Molecular cloning of bovine zona pellucida glycoproteins ZPA and ZPB and analysis for sperm-binding component of the zona

The zona pellucida, a transparent envelope surrounding the mammalian oocyte, comprises three glycoproteins, ZPA, ZPB and ZPC, and plays important roles in fertilization. We have previously reported that apparent relative molecular masses of bovine zona glycoproteins on SDS/PAGE under nonreducing conditions after removal of poly N-acetyllactosamine at the nonreducing portion of sugar chains with endo-beta-galactosidase are 72 000, 58 000 and 45 000 [Noguchi, S., Yonezawa, N., Katsumata, T., Hashizume, K.,Kuwayama, M., Hamano, S., Watanabe, S. & Nakano, M. (1994) Biochim. Biophys. Acta 1201, 7-14]. The N-terminal amino-acid sequences and crossreactivity to antibodies specific to each porcine zona component show that the bovine components correspond to porcine ZPA, ZPB and ZPC, respectively. In this study, we deduced amino-acid sequences of bovine ZPA and ZPB by cDNA cloning and sequencing. Identities in amino-acid sequences between bovine and porcine counterparts were 77% for ZPA and 75% for ZPB, whereas between bovine and murine counterparts identities were 57% for ZPA and 37% for ZPB. The positions of Cys were completely conserved in bovine ZPA and ZPB compared with counterparts of other mammalian species. Bovine ZPA was processed between Ala and Asp on fertilization, suggesting that the consensus motif for the processing is Ala-Asp-Asp/Glu. We purified bovine zona components and examined their sperm-binding activity with an in vitro competition assay and sperm-bead-binding assay. As a result, ZPB showed the strongest sperm-binding activity among the components. ZPC also showed sperm-binding activity and the activity per molecule was about one-sixth that of ZPB according to the result of the sperm-bead-binding assay. We could not determine if ZPA has significant sperm-binding activity, but the activity may be much lower than that of ZPB even if ZPA has significant activity. Thus, ZPB may play a major role in sperm binding in bovine zona.

Postoperative detection of alpha-fetoprotein mRNA in blood as a predictor for metastatic recurrence of hepatocellular carcinoma

BACKGROUND

We tested for the presence of alpha-fetoprotein (AFP) mRNA by using nested RT-PCR in the peripheral blood of hepatocellular carcinoma (HCC) patients who had undergone curative surgery, and investigated the occurrence of intrahepatic and/or extrahepatic metastasis thereafter, to reveal the optimal timing of blood sampling for the prediction of metastatic recurrence.

METHODS

Twenty-nine patients with HCC, who had been operated on were analyzed with RT-PCR at several points during the clinical course, and examined for metastatic recurrence for 3-28 months (mean = 18.7 months) after surgery.

RESULTS

The presence of AFP mRNA before surgery was significantly correlated with the tumor size (P = 0.017). Metastatic recurrence was associated with the postoperative detection of AFP mRNA (P < 0.001), but not with the preoperative and/or perioperative detection. Furthermore, AFP mRNA was detected in some cases that showed low serum AFP levels at recurrence. The recurrence-free period after the detection of AFP mRNA varied from 1 to 12 months.

CONCLUSIONS

The postoperative detection of AFP mRNA is useful for the prediction of metastatic recurrence, and long-term follow up with this method should be conducted.

Temporal fluctuations of voltage-gated proton currents in rat spinal microglia via pH-dependent and -independent mechanisms

Voltage-gated proton (H(+)) channels are unique mechanisms to extrude a massive amount of H(+), and are proposed to regulate intracellular pH of microglia during respiratory bursts. Temporal variations of the H(+) current were studied in rat spinal microglia cultivated on the glial cell layer using the voltage-ramp protocol. Repetitive applications of the large and long-lasting depolarization decreased the amplitudes of the H(+) current transiently and reversibly. This decrease was accompanied by a shift of the reversal potential to a more positive direction, indicating that a drop in the transmembrane pH gradient (delta pH) by the H(+) efflux through the channel reduced the current. The decline of the H(+) current during depolarizations was also observed in a rat microglial cell line (GMI-R1). An increase in the extracellular buffer suppressed the reduction of the current, suggesting that H(+) secreted into the extracellular space contributed to the drop in delta pH. On the other hand, the amplitudes of the H(+) current often fluctuated greatly at intervals of 5-20 min without changes in delta pH. These results suggest that the H(+) current of microglia is tuned via both delta pH-dependent and -independent mechanisms, which may regulate both microglial behavior and the pH environments of the surrounding neural tissue.

Potentiation of a voltage-gated proton current in acidosis-induced swelling of rat microglia

Microglia are equipped with a strong proton (H(+)) extrusion pathway, a voltage-gated H(+) channel, probably to compensate for the large amount of H(+) generated during phagocytosis; however, little is known about how this channel is regulated in pathological states. Because neural damage is often associated with intracellular and extracellular acidosis, we examined the regulatory mechanisms of the H(+) current of rat spinal microglia in acidic environments. More than 90% of round/amoeboid microglia expressed the H(+) current, which was characterized by slow activation kinetics, dependencies on both intracellular and extracellular pH, and blockage by Zn(2+). Extracellular lactoacidosis, pH 6.8, induced intracellular acidification and cell swelling. Cell swelling was also induced by intracellular dialysis with acidic pipette solutions, pH 5.5-6.8, at normal extracellular pH 7.3 in the presence of Na(+). The H(+) currents were increased in association with cell swelling as shown by shifts of the half-activation voltage to more negative potentials and by acceleration of the activation kinetics. The acidosis-induced cell swelling and the accompanying potentiation of the H(+) current required nonhydrolytic actions of intracellular ATP and were inhibited by agents affecting actin filaments (phalloidin and cytochalasin D). The H(+) current was also potentiated by swelling caused by hypotonic stress. These findings suggest that the H(+) channel of microglia can be potentiated via cell swelling induced by intracellular acidification. This potentiation might operate as a negative feedback mechanism to protect microglia from cytotoxic acidification and hence acidosis-induced swelling in pathological states of the CNS.

The presence of a glycosyl phosphatidylinositol-anchored alpha-mannosidase in boar sperm

alpha-Mannosidase and beta-galactosidase were released from boar sperm into the medium by treatment with calcium ionophore A23187 or by 0.2% Brij-35/2% acetic acid. About half as much alpha-mannosidase activity as that in the acid extract was recovered by digestion with phosphatidylinositol-specific phospholipase C (PI-PLC), whereas the liberation rate of beta-galactosidase treated with PI-PLC was low. These results suggest that some alpha-mannosidase is anchored in the plasma membrane of the acrosomal region by attachment to the lipid phosphatidylinositol and that beta-galactosidase is localized mainly in the acrosome or integrated in the plasma membrane by a spanning stretch of hydrophobic peptides. beta-Galactosidase, which is present as an oligomers in the acid extract of sperm, dissociated into monomers under weakly alkaline conditions; under acidic conditions, the monomers associated again. No pH-sensitive association-dissociation of alpha-mannosidase was observed.

Dual CCK-A and CCK-B receptor antagonists (II). Preparation and structure activity relationships of 5-alkyl-9-methyl-1,4-benzodiazepines and discovery of FR208419

In our continuing research for dual CCK-A and -B antagonists, according to our hypothesis that dual CCK-A and -B antagonists should be more efficacious than selective CCK-A antagonists for the treatment of pancreatitis, we have prepared various 5-alkyl-9-methyl-1,4-benzodiazepines. From the compounds prepared, 1-cyclohexyl-carbonylmethyl-5-ethyl-9-methyl-3- (m-tolylureido)-2-oxo-1,4-benzodiazepine, (40) was selected as a candidate for development due to its well-balanced high affinity for both receptors. The R-enantiomer of 40, (R)-40 (FR 208419), had 27-fold higher affinity for the CCK-A receptor and 8-fold more potent CCK-B receptor binding activity than (S)-40. The biological activity after p.o. administration of (R)-40, estimated from the ID50 value (0.23 mg/kg p.o.) obtained by preliminary evaluation by gastric emptying effects, is considered to be high enough for further development. This compound is now undergoing further biological evaluations with a view to clinical development.

Disparity of cell swelling and rapid neuronal death by excitotoxic insults in rat hippocampal slice cultures

The rapidly (< 1 h) developing neuronal death induced by a 15-min-exposure to N-methyl-D-aspartate (NMDA) in rat hippocampal slice cultures is associated with cell swelling. We examined whether the swelling directly leads to neuronal death. The rapid neuronal death assayed by propidium iodide was Cl(-)-dependent, as reported for the cell swelling. However, the dose-dependence for NMDA-induced neuronal death differed from that for the cell swelling. Also, cell swelling alone induced by hypotonic insults led to neuronal death only when the cell size increased far more than the extent achieved by NMDA insults. Moreover, contrary to the previous notion, the rapid neuronal death was Ca2+-dependent. Thus, the primary cause of the rapid neuronal death induced by NMDA cannot be attributed to cell swelling.

Protection of excitotoxic neuronal death by gluconate through blockade of N-methyl-D-aspartate receptors

Excitotoxic neuronal death is mediated primarily by the N-methyl-D-aspartate receptor. N-methyl-D-aspartate induces two forms of excitotoxicity in CA1 pyramidal neurons of cultured rat hippocampal slices: the rapidly developing form that depends on external Na+ and Cl-, and the delayed form that requires external Ca2+ but not Cl-. Consistent with this notion, replacement of external Cl- with glucuronate, isethionate or methylsulfate attenuated or delayed selectively the rapid excitotoxicity. However, gluconate substituting for Cl- blocked both rapid and delayed forms of excitotoxicity. Gluconate also reduced N-methyl-D-aspartate-induced membrane currents recorded from CA1 neurons in a dose-dependent manner. This dose-dependence was remarkably similar to that observed for protection of N-methyl-D-aspartate-induced neuronal death by gluconate. Although gluconate chelated Ca2+ most strongly among the four Cl- substitutes examined, excitotoxic neuronal death could be protected by 7 mM gluconate without Ca2+ chelating action. The voltage-dependent Mg2+ block of N-methyl-D-aspartate receptors was not affected by gluconate. Gluconate suppressed the N-methyl-D-aspartate component of excitatory synaptic currents evoked in CA1 neurons. We conclude that protection of excitotoxic neuronal death by gluconate at low doses (<20 mM) is due to its antagonistic action on N-methyl-D-aspartate receptors. Gluconate is a widely used substitute for Cl-. Our unexpected findings give a warning that the results of any of the experiments concerning excitotoxicity or glutamate receptors obtained by gluconate substituting for Cl- must be interpreted with caution.

Synergetic activation of outwardly rectifying Cl- currents by hypotonic stress and external Ca2+ in murine osteoclasts

1. An outwardly rectifying Cl- (ORCl) current of murine osteoclasts was activated by hypotonic stimulation. The current was characterized by rapid activation, little inactivation, strong outward rectification, blockage by DIDS and permeability to organic acids (pyruvate and glutamate). 2. The hypotonically activated ORCl current was inhibited by intracellular dialysis with an ATP-free pipette solution, but not by replacement of ATP with a poorly hydrolysable ATP analogue adenosine 5'-O-(3-thiotriphosphate). The current amplitude was reduced when intracellular alkalinity increased over the pH range 6.6-8.0. 3. Intracellular application of cytochalasin D occasionally activated the ORCl current without hypotonic stress, but inhibited activation of the ORCl current by hypotonic stimulation. The hypotonically activated ORCl current was unaffected by a non-actin-depolymerizing cytochalasin, chaetoglobosin C, but partially inhibited by deoxyribonuclease I. 4. Removal of extracellular Ca2+ inhibited activation of the ORCl current by hypotonic shock, but did not reduce the current once activated. The hypotonically activated ORCl current was partially decreased by intracellular dialysis with 20 mM EGTA. 5. With 10 mM Ca2+ in the extracellular medium, the ORCl current was activated in response to more minor decreases in osmolarity than with 1 mM Ca2+. The increased sensitivity to hypotonicity was mimicked by increasing the intracellular Ca2+ level (pCa 6.5). 6. These results suggest that hypotonic stimulation and a rise in the extracellular Ca2+ level synergistically activate the ORCl channel of murine osteoclasts, and that the activating process is modified by multiple intracellular factors (pH, ATP and actin cytoskeletal organization).

Effect of FK480, a CCK-A receptor antagonist, on spontaneously developed chronic pancreatitis in WBN/Kob rats

The effect of FK480, a cholecystokinin-A (CCK-A) selective receptor antagonist, on spontaneously developed chronic pancreatitis was examined in WBN/Kob rats. Animals at age 18 weeks (18w-Control) already had the histologic appearance of chronic pancreatitis as indicated by inflammatory cell infiltration and fibrotic degeneration with interstitial edema. Rats treated with vehicle from 18 to 26 weeks of age (26w-Control) showed further development of pancreatitis as characterized by more extensive appearance of inflammatory cell infiltration and fibrotic changes, with the pancreatic weight significantly decreased. Serum amylase levels of 26w-Control animals were slightly decreased compared with those of 18w-Control animals, although the difference was not statistically significant. When rats were treated orally with 1, 10, and 100 microg/kg FK480 from 18 to 26 weeks of age, the decrease in serum amylase levels recovered dose dependently compared with 26w-Control, and the level in animals treated with 100 microg/kg FK480 was almost the same as that in 18w-Control rats. Histologic examinations revealed that the appearance of the pancreas of animals treated with FK480 was slightly improved with respect to inflammatory cell infiltration and edematous changes at the highest dose examined, although the difference was not statistically significant. Although blockade of the CCK-A receptor could be considered to exacerbate chronic pancreatitis due to possible inhibition of the trophic action of CCK, our results suggest that CCK-A receptor antagonists may not be detrimental to chronic pancreatitis.

Augmentation of the inhibitory effect of FK480, a CCK-A receptor antagonist, on pancreatic exocrine secretion by achlorhydria

The effect of intraluminal acid and cholecystokinin (CCK) receptor blockade on the pancreatic secretory response was examined in rats. Blockade of gastric acid secretion by YM022 (CCK-B receptor antagonist) or famotidine (histamine-2 receptor antagonist) resulted in a significant suppression of casein-stimulated pancreatic exocrine secretion as determined by juice volume and amylase secretion. Ligation of the gastric pylorus, which leads to complete prevention of gastric acid from entering the duodenum, also suppressed pancreatic exocrine secretion. FK480 (CCK-A receptor antagonist) inhibited pancreatic exocrine secretion dose dependently at doses of 0.01-1.0 mg/kg. When submaximal doses of FK480 and YM022 were treated concomitantly, pancreatic exocrine secretion was inhibited more profoundly than when treated solely. Hydrochloric acid (HCl; 0.05 N), injected into the duodenum, stimulated pancreatic exocrine secretion to a level comparable to that exhibited by intraduodenal casein. This effect of HCl was inhibited by FK480 (1.0 mg/kg) but not by YM022 (1.0 mg/kg). These findings suggest that inhibition of gastric acid secretion leads to the suppression of pancreatic exocrine secretion through mechanisms mediated by CCK-A receptors.

Strain difference in the induction of T-cell activation-associated, interferon gamma-dependent hepatic injury in mice

A single intravenous injection of concanavalin A (Con A) induces T-cell activation-associated inflammatory injury selectively in the liver. This study investigated the strain difference in the development of Con A-induced hepatic injury. Normal C57BL/6 and BALB/c spleen cells produced comparable levels of T-cell-derived lymphokines (interferon gamma [IFN-gamma], tumor necrosis factor alpha [TNF-alpha], and interleukin-2 [IL-2]) following in vitro stimulation with Con A. A single intravenous injection of Con A to C57BL/6 mice induced the plasma levels of TNF-alpha and IL-2 comparable with or slightly higher than those observed in BALB/c mice, whereas the same treatment resulted in an apparently lower level of IFN-gamma production in C57BL/6 mice. RNA from livers of Con A-treated C57BL/6 mice exhibited lower levels of IFN-gamma mRNA than RNA of BALB/c livers. Unexpectedly, a dramatic difference in the severity of hepatic injury was observed between C57BL/6 and BALB/c. Namely, the peak alanine transaminase (ALT) level was more than 15,000 U/L and inducible as early as 8 hours after injection of 0.2 mg Con A per mouse in the C57BL/6 strain, whereas the peak was approximately 3,000 U/L and induced as late as 24 hours after Con A injection in the BALB/c strain. The increase in plasma ALT levels was limited to less than 10% by injection of anti-IFN-gamma monoclonal antibody (mAb) in both strains. The C57BL/6 strain inducing lower levels of IFN-gamma exhibited higher IFN-gamma responsiveness as exemplified by the intrahepatic expression of an IFN-gamma-inducible gene, an inducible type of nitric oxide (NO) synthase (iNOS). These results indicate that, while IFN-gamma produced in vivo by activated T cells induces hepatic injury, there exists a striking strain difference in the induction of IFN-gamma-dependent hepatic injury.

Differential effect of high extracellular Ca2+ on K+ and Cl- conductances in murine osteoclasts

Effects of the extracellular Ca2+ concentration ([Ca2+]o) on whole cell membrane currents were examined in mouse osteoclastic cells generated from bone marrow/stromal cell coculture. The major resting conductance in the presence of 1 mm Ca2+ was mediated by a Ba2+-sensitive, inwardly rectifying K+ (IRK) current. A rise in -Ca2+-o (5-40 mM) inhibited the IRK current and activated an 4'4'-diisothiocyano-2,2'-stilbenedisulfonate (DIDS)-sensitive, outwardly rectifying Cl- (ORCl) current. The activation of the ORCl current developed slowly and needed higher [Ca2+]o than that required to inhibit the IRK current. The inhibition of the IRK current consisted of two components, initial and subsequent late phases. The initial inhibition was not affected by intracellular application of guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS) or guanosine 5'-O-(2-thiodiphosphate) (GDPbetaS). The late inhibition, however, was enhanced by GTPgammaS and attenuated by GDPbetaS, suggesting that GTP-binding proteins mediate this inhibition. The activation of the ORCl current was suppressed by pretreatment with pertussis toxin, but not potentiated by GTPgammaS. An increase in intracellular Ca2+ level neither reduced the IRK current nor activated the ORCl current. Staurosporine, an inhibitor for protein kinase C, did not modulate the [Ca2+]o-induced changes in the IRK and ORCl conductances. These results suggest that high [Ca2+]o had a dual action on the membrane conductance of osteoclasts, an inhibition of an IRK conductance and an activation of an ORCl conductance. The two conductances modulated by [Ca2+]o may be involved in different phases of bone resorption because they differed in Ca2+ sensitivity, temporal patterns of changes and regulatory mechanisms.