Restricted growth of U-type infectious haematopoietic necrosis virus (IHNV) in rainbow trout cells may be linked to casein kinase II activity

Previously, we demonstrated that a representative M genogroup type strain of infectious haematopoietic necrosis virus (IHNV) from rainbow trout grows well in rainbow trout-derived RTG-2 cells, but a U genogroup type strain from sockeye salmon has restricted growth, associated with reduced genome replication and mRNA transcription. Here, we analysed further the mechanisms for this growth restriction of U-type IHNV in RTG-2 cells, using strategies that assessed differences in viral genes, host immune regulation and phosphorylation. To determine whether the viral glycoprotein (G) or non-virion (NV) protein was responsible for the growth restriction, four recombinant IHNV viruses were generated in which the G gene of an infectious IHNV clone was replaced by the G gene of U- or M-type IHNV and the NV gene was replaced by NV of U- or M-type IHNV. There was no significant difference in the growth of these recombinants in RTG-2 cells, indicating that G and NV proteins are not major factors responsible for the differential growth of the U- and M-type strains. Poly I:C pretreatment of RTG-2 cells suppressed the growth of both U- and M-type IHNV, although the M virus continued to replicate at a reduced level. Both viruses induced type 1 interferon (IFN1) and the IFN1 stimulated gene Mx1, but the expression levels in M-infected cells were significantly higher than in U-infected cells and an inhibitor of the IFN1-inducible protein kinase PKR, 2-aminopurine (2-AP), did not affect the growth of U- or M-type IHNV in RTG-2 cells. These data did not indicate a role for the IFN1 system in the restricted growth of U-type IHNV in RTG-2 cells. Prediction of kinase-specific phosphorylation sites in the viral phosphoprotein (P) using the NetPhosK program revealed differences between U- and M-type P genes at five phosphorylation sites. Pretreatment of RTG-2 cells with a PKC inhibitor or a p38MAPK inhibitor did not affect the growth of the U- and M-type viruses. However, 100 μm of the casein kinase II (CKII) inhibitor, 5,6-dichloro-1-β-d-ribofuranosylbenzimidazole (DRB), reduced the titre of the U type 8.3-fold at 24 h post-infection. In contrast, 100 μm of the CKII inhibitor reduced the titre of the M type only 1.3-fold at 48 h post-infection. Our data suggest that the different growth of U- and M-type IHNV in RTG-2 cells may be linked to a differential requirement for cellular protein kinases such as CKII for their growth.

Differential growth of U and M type infectious haematopoietic necrosis virus in a rainbow trout-derived cell line, RTG-2

Infectious haematopoietic necrosis virus (IHNV) is one of the most important viral pathogens of salmonids. In rainbow trout, IHNV isolates in the M genogroup are highly pathogenic, while U genogroup isolates are significantly less pathogenic. We show here that, at a multiplicity of infection (MOI) of 1, a representative U type strain yielded 42-fold less infectious virus than an M type strain in the rainbow trout-derived RTG-2 cell line at 24 h post-infection (p.i.). However, at an MOI of 10, there was only fivefold difference in the yield of infectious virus between the U and M strains. Quantification of extracellular viral genomic RNA suggested that the number of virus particles released from cells infected with the U strain at a MOI of 1 was 47-fold lower than from M-infected cells, but U and M virions were equally infectious by particle to infectivity ratios. At an MOI of 1, U strain intracellular viral genome accumulation and transcription were 37- and 12-fold lower, respectively, than those of the M strain at 24 h p.i. Viral nucleocapsid (N) protein accumulation in U strain infections was fivefold lower than in M strain infections. These results suggest that the block in U type strain growth in RTG-2 cells was because of the effects of reduced genome replication and transcription. The reduced growth of the U strain does not seem to be caused by defective genes, because the U and M strains grew equally well in the permissive epithelioma papulosum cyprini cell line at an MOI of 1. This suggests that host-specific factors in RTG-2 cells control the growth of the IHNV U and M strains differently, leading to growth restriction of the U type virus during the RNA synthesis step.

Diazoxide acts more as a PKC-epsilon activator, and indirectly activates the mitochondrial K(ATP) channel conferring cardioprotection against hypoxic injury

BACKGROUND AND PURPOSE

Diazoxide, a well-known opener of the mitochondrial ATP-sensitive potassium (mitoK(ATP)) channel, has been demonstrated to exert cardioprotective effect against ischemic injury through the mitoK(ATP) channel and protein kinase C (PKC). We aimed to clarify the role of PKC isoforms and the relationship between the PKC isoforms and the mitoK(ATP) channel in diazoxide-induced cardioprotection.

EXPERIMENTAL APPROACH

In H9c2 cells and neonatal rat cardiomyocytes, PKC-epsilon activation was examined by Western blotting and kinase assay. Flavoprotein fluorescence, mitochondrial Ca(2+) and mitochondrial membrane potential were measured by confocal microscopy. Cell death was determined by TUNEL assay.

KEY RESULTS

Diazoxide (100 microM) induced translocation of PKC-epsilon from the cytosolic to the mitochondrial fraction. Specific blockade of PKC-epsilon by either epsilonV1-2 or dominant negative mutant PKC-epsilon (PKC-epsilon KR) abolished the anti-apoptotic effect of diazoxide. Diazoxide-induced flavoprotein oxidation was inhibited by either epsilonV1-2 or PKC-epsilon KR transfection. Treatment with 5-hydroxydecanoate (5-HD) did not affect translocation and activation of PKC-epsilon induced by diazoxide. Transfection with wild type PKC-epsilon mimicked the flavoprotein-oxidizing effect of diazoxide, and this effect was completely blocked by epsilonV1-2 or 5-HD. Diazoxide prevented the increase in mitochondrial Ca(2+), mitochondrial depolarization and cytochrome c release induced by hypoxia and all these effects of diazoxide were blocked by epsilonV1-2 or 5-HD.

CONCLUSIONS AND IMPLICATIONS

Diazoxide induced isoform-specific translocation of PKC-epsilon as an upstream signaling molecule for the mitoK(ATP) channel, rendering cardiomyocytes resistant to hypoxic injury through inhibition of the mitochondrial death pathway.

Comparison of the immunogenicity of recombinant VP2 and VP3 of infectious pancreatic necrosis virus and marine birnavirus

Recombinant proteins of truncated viral protein-2 (VP2) (aa 79-359) and VP3 of infectious pancreatic necrosis virus (IPNV) and marine birnavirus (MABV) were expressed in E. coli and their immunogenicities in fish were investigated. The recombinant proteins from IPNV were used to immunize rainbow trout and those from MABV to immunize flounder. The sera from the immunized fishes were assayed for antibody by ELISA and a neutralization test. Both the recombinant VP2 and VP3 produced antibodies in fish but the VP3 antibody titers were higher than that of the VP2 of IPNV and MABV. These results indicate that the recombinant VP3 is more immunogenic than the recombinant VP2.

Rutaecarpine, a quinazolinocarboline alkaloid, inhibits prostaglandin production in RAW264.7 macrophages

In order to delineate the mechanism involved in the anti-inflammatory activity of rutaecarpine, its effects on the production of prostaglandin (PG) and therein involved enzymes were examined. Rutaecarpine reduced the production of PGE(2) in RAW264.7 cells treated with lipopolysaccharide (LPS) in a dose dependent manner when added to the culture media at the time of stimulation. However, the inhibition of total cellular cyclooxygenase (COX) activity under the same experimental condition was observed only at high concentrations of rutaecarpine. Rutaecarpine did not affected the levels of COX-2 mRNA and protein in macrophages stimulated with LPS. Calcium ionophore A23187 induced-PG production and [(3)H]-arachidonic acid release were significantly decreased by the pretreatment of rutaecarpine for 30 minutes. With the same treatment schedule, however, rutaecarpine failed to alter the activities of cellular COX-1 and COX-2. Collectively, our data suggest that anti-inflammatory effect of rutaecarpine is, at least in part, ascribed to the diminution of PG production through inhibition of arachidonic acid release albeit the nature of its effects on PLA(2) activity remains to be elaborated.

Differential roles of cyclooxygenase isoforms after kainic acid-induced prostaglandin E(2) production and neurodegeneration in cortical and hippocampal cell cultures

Prostaglandins, which are cyclooxygenase (COX) products, are pathologically up-regulated, and have been proven to be closely associated with neuronal death. In this study, we investigated a role of COX isoforms (COX-1 and COX-2) in kainic acid-induced neuronal death in cultured murine cortical or hippocampal neurons. In primary cortical neurons, both indomethacin (COX-1/-2 nonselective inhibitor) and aspirin (COX-1 preferential inhibitor) reduced basal and kainic acid-induced PGE(2) production significantly and prevented neuronal cell death after kainic acid treatment. In contrast, NS398 (COX-2 selective inhibitor) had no effect on kainic acid-induced neuronal cell death. In hippocampal neurons, however, COX-2 inhibitors prevented both kainic acid-induced neuronal death and PGE(2) production. COX-2 expression was remarkably up-regulated by kainic acid in hippocampal neurons; whereas in cortical neurons, COX-2 expression was comparatively less significant. Astrocytes were unresponsive to kainic acid in terms of PGE(2) production and cell death. In conclusion, we suggest that the release of PGE(2) induced by kainic acid occurred through COX-1 activity rather than COX-2 in cortical neurons. The inhibition of PGE(2) release by COX-1 inhibitors prevented kainic acid-induced cortical neuronal death, while in the hippocampal neurons, COX-2 inhibitors prevented kainic acid-induced PGE(2) release and hippocampal neuronal death.

Protein kinase C inhibitors attenuate protective effect of high glucose against hypoxic injury in H9c2 cardiac cells

In this study, we demonstrated that PKC inhibitors significantly attenuated the cardioprotective effect produced by high-glucose (22 mM) treatment for 48 h against hypoxic injury in H9c2 cardiac cells. PKC activators mimicked the cardioprotective effect of high glucose. These results suggest a possible role of PKC activation in high-glucose--induced protection.

High glucose enhances IL-1beta-induced cyclooxygenase-2 expression in rat vascular smooth muscle cells

The changes in vascular prostaglandin production are implicated in the derangement of vascular reactivity in diabetes. However, the mechanism of altered prostaglandin (PG) production in diabetes is largely unknown. In this study, we investigated the effect of high glucose on IL-1beta-induced PG production and the possible underlying mechanism in cultured vascular smooth muscle cell (VSMC). High glucose evoked an augmentation of IL-1beta-induced PG synthesis in a dose dependent manner and enhanced cyclooxygenase (COX) activity, which reached to maximum at 8-12 hours after stimulation. Western blot analysis supported the activity data. Protein kinase C (PKC) inhibitors, H-7 and chelerythrine, significantly inhibited the enhancement of IL-1beta-induced COX-2 expression by high glucose. The activation of PKC by PMA resulted in marked increase of PG production in low glucose group, whilst this was not the case in high glucose group. Furthermore, glucose-enhancing effect was significantly suppressed by zopolrestat, an aldose reductase inhibitor, and sodium pyruvate. These results suggest that the augmenting effect of high glucose on IL-1beta-induced PG production and COX-2 expression is, at least in part, due to increased glucose metabolism via sorbitol pathway following PKC activation.

Outcome from injury: general health, work status, and satisfaction 12 months after trauma

OBJECTIVE

We evaluated outcomes 12 months after trauma in terms of general health, satisfaction, and work status.

METHODS

Two hundred forty-seven patients without severe neurotrauma were evaluated by interview during admission and by mailed self-report 6 and 12 months after trauma. Data were obtained from the Trauma Registry, interviews, and survey instruments. Baseline assessment was obtained with the Short Form 36 (SF36) and the Sickness Impact Profile (SIP) work scale. Outcome measures were the SF36, SIP work scale, Brief Symptom Inventory (BSI) depression scale, the Civilian Mississippi Scale for Posttraumatic Stress Disorder (PTSD), and a satisfaction questionnaire. Three regressions were determined for outcome. The dependent variables were general health and work status (linear) and satisfaction (logistic). Each regression controlled for baseline status and mental health, Injury Severity Score (ISS), and 12-month SF36 physical function before evaluating the effect of outcome mental health.

RESULTS

Follow-up data were available for 75% of the patients at 6 months and 51% at 12 months. The mean age of patients was 37.2 +/- 0.9 years (+/-SEM), and 73% were male. Their average ISS was 13.9 +/- 0.6. Seventy percent of injuries were blunt force, 13.5 % were penetrating, and 16.5 % were burn injuries (mean total body surface area, 13.3 +/- 1.5%). Sixty-four percent of the patients had returned to work at 12 months. Follow-up SF36 mental health was associated with the dependent outcome in each regression. After controlling for baseline status and mental health, ISS, and outcome SF36 physical function, outcome mental health was associated with outcome SF36 general health (p < 0.001), SIP work status (p = 0.017), and satisfaction with recovery (p = 0.005). Outcome SF36 mental health was related to baseline mental health, 12-month PTSD and BSI depression scores, and increased drug and alcohol use.

CONCLUSIONS

Twelve months after trauma, patients' work status, general health, and overall satisfaction with recovery are dependent on outcome mental health. This dependency persists despite measured baseline status, ISS, or physical recovery. The mental disease after trauma is attributable to poor mental health, the development of symptoms of PTSD and depression, and increased substance abuse. Trauma centers that fail to recognize, assess, and treat these injury-related mental health outcomes are not fully assisting their patients to return to optimal function.

Mechanism for antiplatelet effect of onion: AA release inhibition, thromboxane A(2)synthase inhibition and TXA(2)/PGH(2)receptor blockade

Antiplatelet actions of aqueous extract of onion were investigated in rat and human platelet. IC(50)values of onion extract for collagen-, thrombin-, arachidonic acid (AA)-induced aggregations and collagen-induced thromboxane A(2)(TXA(2)) formation were 0.17 +/- 0. 01, 0.23 + 0.03, 0.34 +/- 0.02 and 0.12 +/- 0.01 g/ml, respectively. [(3)H]-AA release induced by collagen (10 microg/ml) in rat platelet was decreased by onion compared to control (22.1 +/- 2.13 and 5.2 +/- 0.82% of total [(3)H]-AA incorporated, respectively). In fura-2 loaded platelets, the elevation of intracellular Ca(2+)concentration stimulated by collagen was inhibited by onion. Onion had no cytotoxic effect in platelet. Onion significantly inhibited TXA(2)synthase activity without influence on COX activity. Platelet aggregation induced by U46619, a stable TXA(2)mimetic, was inhibited by onion, indicating its antagonism for TXA(2)/PGH(2)receptor. These results suggest that the mechanism for antiplatelet effect of onion may, at least partly, involve AA release diminution, TXA(2)synthase inhibition and TXA(2)/PGH(2)receptor blockade.

4-1BB: still in the midst of darkness

4-1BB is a member of the tumor necrosis factor receptor superfamily. The receptor functions mainly as a costimulatory molecule in T lymphocytes. In addition, several lines of evidence have shown that interactions between 4-1BB and its ligand are involved in the antigen presentation process and the generation of cytotoxic T cells. Recent studies, however, have demonstrated that 4-1BB plays more diverse roles: Signals through 4-1BB are important for long-term survival of CD8+ T cells and the induction of helper T cell anergy. Clinically, there is great interest in 4-1BB, because T-cell activation induced by anti-4-1BB monoclonal antibodies is highly efficient in the eradication of established tumor cells in mice. Now, since mice deficient in 4-1BB or the 4-1BB ligand are available, subtle roles played by 4-1BB may be revealed in the near future.

An animal model of neuropathic pain employing injury to the sciatic nerve branches

The present study was conducted to develop a new animal model of neuropathic pain employing injury to the distal sciatic nerve branches. Under halothane anesthesia, the tibial, sural, and/or common peroneal nerves were injured and neuropathic pain behaviors were compared among different groups of rats. Different types of injury produced different levels of neuropathic pain. Rats with injury to the tibial and sural nerves showed the most vigorous mechanical allodynia, cold allodynia, and spontaneous pain. These neuropathic pain behaviors were not relieved by functional sympathectomy using guanethidine. The results suggested that injury to the tibial and sural nerves, while leaving the common peroneal nerve intact, can be used as a new animal model of neuropathic pain and that this model represents sympathetically independent pain (SIP). The present animal model is very simple to produce injury and can produce profound and reliable pain behaviors. These features enable the new animal model to be a useful tool in elucidating the mechanisms of neuropathic pain, especially SIP.

Posttraumatic stress disorder in injured adults: etiology by path analysis

OBJECTIVE

Posttraumatic Stress Disorder (PTSD) impairs outcome from injury. We present a path analysis of factors related to the development of PTSD in injured adults.

METHODS

A prospective cohort of 250 patients without severe neurotrauma was evaluated by interview during admission and by mailed self-report 6 months later. Data were gathered from the trauma registry (age, injury mechanism, and Injury Severity Score), social history (gender, income, education, and social support), and survey instruments. Baseline assessment used the Michigan Critical Events Perception Scale (peritraumatic dissociation and subjective threat to life), the Life Experience Survey (stressful exposure history), and the SF36 (general and mental health). PTSD at 6 months was identified with the civilian Mississippi Scale for PTSD. Data are listed as mean +/- SEM or percent (%). Path analysis was conducted by linear regression and significant (p<0.05) variables are shown. Factors are listed with the standardized beta. A negative beta suggests a protective effect.

RESULTS

The 176 patients (72%) who completed the 6-month follow-up were 37.7+/-0.88 years old; 75% were men; and blunt (70%), penetrating (13.5%), and burn (16.4%) mechanisms caused the injuries. Assault was involved in 14.5% of the cases. Average income was $44,300+/-2,700/yr, education was 13.0+/-0.15 years, and Injury Severity Score was 13.9+/-0.50. A total of 42.3% of the patients developed PTSD. The 39.7% of the variance in PTSD explained by the model was due to intentional injury (beta = 0.27), male gender (beta = -0.21), age (beta = -0.20), peritraumatic dissociation (beta = 0.174), baseline mental health (beta = -0.21), and prior life-threatening illness (beta = -0.29). Peritraumatic dissociation was due to the patient's sense of threat to life (beta = -0.47), and threat was related to Injury Severity Score (beta = 0.2), assault(beta = 0.14), education (beta = -0.15), and age (beta = -0.19). Baseline SF36 mental health was related to social support (beta = 0.27) and income (beta = 0.21). Income was contingent on education (beta = 0.21).

CONCLUSION

PTSD occurred in 42.3% of injured adults 6 months after trauma and was related to assault, dissociation, female gender, youth, poor mental health, and prior illness. By modeling PTSD, we may learn more of the etiology, risk stratification, and potentials for the treatment of this common and important morbidity of injury.

Protein kinase C inhibitors abolish the increased resistance of diabetic rat heart to ischemia-reperfusion injury

Protein kinase C (PKC) has been implicated in ischemic preconditioning, but whether it plays a role in the cardioprotection observed in the diabetic heart is not known. We assessed the possible role of PKC by investigating whether the inhibition of PKC with staurosporine (Stau, 0.01 microM) or chelerythrine (Chel, 1 microM) can abolish the increased resistance to ischemia (25 min)-reperfusion (30 min) injury in Langendorff perfused hearts from streptozotocin-induced 4-week diabetic rats. In the diabetic heart, pre-ischemic left ventricular developed pressure (LVDP), double product (DP: LVDPxheart rate/1,000), +/- dP/dt(max) and coronary flow rate (CFR) were all reduced compared to the control. The pretreatment with Stau or Chel significantly improved these parameters. The post-ischemic contractile function was recovered to a greater extent in the diabetic heart (116.9 +/- 20.5% of pre-ischemic DP) than in the control (23.3 +/- 2.3% of pre-ischemic DP), indicating the increased resistance of the diabetic heart to ischemia-reperfusion injury. The treatment with Stau or Chel abolished the enhanced recovery in the diabetic heart (36.0 +/- 14.6 and 54.1 +/- 12.8% of pre-ischemic DP, respectively). The reduction in post-ischemic end diastolic pressure (EDP) and lactate dehydrogenase (LDH) release in diabetes (13.5 +/- 2.5 mmHg and 27.2 +/- 6.2 U/g heart) compared to the control (55.8 +/- 2.9 mmHg and 60. 3 +/- 5.7 U/g heart) was significantly (p<0.05) increased by pretreatment with Stau (39.0 +/- 4.9 mmHg and 53.1 +/- 7.6 U/g heart) or Chel (36.2 +/- 3.0 mmHg and 48.8 +/- 4.3 U/g heart). Neither Stau nor Chel had any influence on the post-ischemic values of LVDP, DP, +/- dP/dt(max), EDP and LDH release in the control heart. In the conclusion, the present results suggest that PKC activation may, at least in part, contribute to the increased resistance of the diabetic heart to ischemia-reperfusion injury.

Posttraumatic stress disorder after injury: impact on general health outcome and early risk assessment

OBJECTIVE

To evaluate prospectively components of general health outcome after trauma and to report on the further validation of the Michigan Critical Events Perception Scale (MCEPS), an instrument that predicts increased risk for posttraumatic stress disorder (PTSD).

METHODS

Adults without neurologic injury admitted to a Level I trauma center in 1997 were interviewed during hospitalization. Baseline data included demographics, injury mechanism, Injury Severity Score, the Short Form 36 (SF36), and the MCEPS, which measures peri-traumatic dissociation (the sense of depersonalization or derealization during an injury event). Surveys sent by mail and completed 6 months later included the SF36 and civilian Mississippi Scale for PTSD.

RESULTS

A total of 140 patients were interviewed; the 70% (n = 100 patients) who completed the 6-month assessment form the study group. Injuries were categorized as 71% blunt, 13% penetrating, and 16% burn. Mean Injury Severity Score was 13.7+/-0.52. PTSD at 6 months occurred in 42% of the patients and was directly related to MCEPS dissociation (p = 0.001; odds ratio = 3.1; 95% confidence interval, 1.6, 5.9). A stepwise linear regression explains 40% of the variance in 6-month SF36 general health outcome (adjusted R2 = 0.402). The model controls for individual factors related to dissociation, PTSD, and general health outcome. Development of PTSD was independently and inversely related to general health outcome as measured by the SF36 at 6 months (p < 0.001, beta = -0.404). The R2 change of 0.132 for PTSD (vs. 0.082 for 6-month physical function) illustrates that PTSD contributes more to the patient's perceived general health at 6 months than the degree of physical function or injury severity.

CONCLUSIONS

Within hours of injury, the MCEPS identifies patients who are three times more likely to develop PTSD. PTSD compromises self-reported general health outcome in injured adults independent of baseline status, Injury Severity Score, or degree of physical recovery. These data suggest that psychological morbidity is an important part of the patient's perceived general health.

Can you spot the signs of elder mistreatment?

The incidence of elder mistreatment is expected to increase as the baby boom generation ages and more elderly people are living or receiving care at home. Despite increased awareness and reporting of other forms of domestic abuse and neglect, recognition and management of elder abuse lag far behind actual incidents. Drs Kruger and Moon describe the signs of mistreatment as well as the physician's role in reporting and management.

Systemically administered capsazepine prevents the capsaicin-induced functional desensitization and loss of substance P-like immunoreactivity (SP-LI) in guinea-pig bronchi

In this study, we investigated whether the systemically administered capsazepine can prevent the capsaicin-induced desensitization ex vivo in guinea-pig bronchi. Pretreatment with capsaicin (2.5, 5 and 10 mg/kg, s.c.) induced the functional desensitization and the loss of substance P-like immunoreactivity (SP-LI) with a similar potency (ED50: 3.31 +/- 0.57 and 4.81 +/- 0.89 mg/kg, respectively) in isolated guinea-pig bronchi. Capsazepine (30 mg/kg, s.c.) co-administered with capsaicin (5 mg/kg, s.c.) prevented the capsaicin (5 mg/kg, s.c.)-induced functional desensitization and loss of SP-LI. These results suggest that capsazepine can antagonize systemically the desensitizing action of capsaicin at the level of receptor, preventing the loss of SP-LI and the establishment of functional desensitization in guinea-pig bronchi.

Capsaicin-induced desensitization is prevented by capsazepine but not by ruthenium red in guinea pig bronchi

In isolated guinea pig bronchi, the influence of ruthenium red, capsazepine and extracellular Ca2+ on capsaicin-induced desensitization was examined to investigate whether this desensitization was mediated via a specific receptor coupled with an ion channel. Pre-exposure of tissues to capsaicin (1, 3 or 10 microM) caused a dose-dependent desensitization to the second application of capsaicin. However, the contractile responses to exogenous tachykinins were not changed after pre-exposure of tissues to capsaicin. This capsaicin-induced desensitization was prevented by capsazepine (30 microM), but not by ruthenium red added to tissues 20 min before pretreatment with capsaicin (3 microM). While the excitatory contractile response to capsaicin was markedly reduced in the absence of extracellular Ca2+, the desensitization induced by capsaicin was not changed by the removal of extracellular Ca2+. In summary, the results from the present study suggest that in vitro functional desensitization induced by capsaicin in guinea pig bronchi may involve changes in the vanilloid receptor and occur through a ruthenium red-insensitive pathway.

Giant-cell interstitial pneumonia in a gas station worker

Giant-cell interstitial Pneumonia (GIP) is a very uncommon respiratory disease. The majority of cases of GIP are caused by exposure to cobalt, tungsten and other hard metals. In this report, we describe GIP in a patient who worked in gas station and dealt in propane gas vessels. He presented with clinical features of chronic interstitial lung disease and underwent an open lung biopsy that showed DIP-like reaction with large numbers of intra-alveolar macrophages and numerous large, multinucleated histiocytes which were admixed with the macrophages. Analysis of lung tissue for hard metals was done. Cobalt was the main component of detected hard metals. Corticosteroid therapy was started and he recovered fully.

Pharmacokinetics of losartan and its metabolite, EXP3174, after intravenous and oral administration of losartan to rats with streptozotocin-induced diabetes mellitus

The pharmacokinetics of losartan and its active metabolite, EXP3174, were investigated after intravenous and oral administration of the drug, 5 mg/kg, to control rats and streptozotocin-induced diabetes mellitus rats (SIDRs). After 1-min intravenous infusion, the mean arterial plasma concentrations and the resultant area under the plasma concentration-time curve from zero to infinity (AUC) of both losartan and EXP3174 were not significantly different between control rats and the SIDRs. However, the renal clearance (CLR) of losartan (0.181 versus 0.0815 ml/min/kg) and EXP3174 (0.0677 versus 0.0277 ml/min/kg) were significantly faster in SIDRs than in control rats due to significant increase in glomerular filtration rate. After oral administration, the mean arterial plasma concentrations and the resultant AUC of losartan (97 versus 166 micrograms min/ml) and EXP3174 (244 versus 423 micrograms min/ml) were significantly lower in SIDRs than in control rats. The absolute extent of oral bioavailability of losartan, F, (32.5 versus 55.1%) decreased considerably in SIDRs and it was possibly due to the reduced gastrointestinal absorption of losartan by gastrointestinal disorders occurring in the diabetic state. The low F in both groups of rats was at least partially due to the increase in first-pass effects. The CLR of losartan (0.207 versus 0.101 ml/min/kg) and EXP3174 (0.0615 versus 0.0196 ml/min/kg) were significantly faster in SIDRs than in control rats after oral administration of losartan.

Molecular cloning of a novel GTP-binding protein induced in fish cells by rhabdovirus infection

We have cloned and sequenced a cDNA encoding GTP-binding protein from a fish cell, CHSE-214. The clone was 1493 bp long and contained an open reading frame encoding 364 amino acids. It has the five sequence motifs G1-G5 that are conserved in all GTP-binding proteins. Its amino acid sequences are strikingly different from those of the well-characterized G-proteins. However, sequences closely related to this protein are found in various kinds of species including human, Arabidopsis, Drosophila and archaebacteria, suggesting a novel subfamily within the superfamily of the GTP-binding proteins. Northern analysis indicates that this gene is constitutively expressed at a low level in normal cells but is induced by fish rhabdovirus infection at about 24 h post infection and disappears thereafter. Based on these observations, we propose that this protein represents an evolutionarily conserved novel subfamily of GTP-binding proteins which may play an important role in fish rhabdovirus infection.

Psychosocial factors limit outcomes after trauma

BACKGROUND

Psychological morbidity compromises return to work after trauma. We demonstrate this relationship and present methods to identify risks for significant psychological morbidity.

METHODS

Thirty-five adults were evaluated prospectively for return to functional employment after injury using demographic data, validated psychological and health measures, and the Michigan Critical Events Perception Scale. Evaluation was conducted at admission and at 1 and 5 months after injury.

RESULTS

Poor return to work at 5 months was attributable to physical disability (p < 0.05) and psychological disturbance (p < 0.05) in a regression model that controlled for preinjury employment and psychopathologic factors as well as injury severity. A high score on the Impact of Events Scale administered during acute admission predicted development of acute stress disorder at 1 month (p < 0.01, odds ratio (OR) = 9.4) and posttraumatic stress disorder at 5 months (p < 0.05, OR = 6.7). Peritraumatic dissociation on the Michigan Critical Events Perception Scale was predictive for development of acute stress disorder (p < 0.05, OR = 5.8) at 1 month and posttraumatic stress disorder (p < 0.05, OR = 7.5) at 5 months.

CONCLUSION

Psychological morbidity after injury compromises return to work independent of preinjury employment and psychopathologic condition, Injury Severity Score, or ambulation. A high Impact of Events Scale score or peritraumatic dissociation at admission predicts this morbidity.

Brazilin inhibits activities of protein kinase C and insulin receptor serine kinase in rat liver

Hypoglycemic action of brazilin was found to be based on the improvement of peripheral glucose utility, and this action might be correlated with the insulin action pathway. In the present study we investigated the effect of brazilin on the insulin receptor autophosphorylation, protein kinase C (PKC), protein phosphatase and insulin receptor serine kinase in order to confirm whether the hypoglycemic mechanism is concerned with insulin action pathway. Brazilin was found to inhibit PKC and insulin receptor serine kinase, which are involved in the regulation of insulin signal pathway. But any significant effect was not shown on insulin receptor tyrosine kinase activity, autophosphorylation and phosphatase activity. These findings suggest that brazilin might enhance insulin receptor function by decreasing serine phosphorylation, which might mediate hypoglycemic effect of brazilin.

A new silent magnetic resonance imaging using a rotating DC gradient

A new approach to silent MR imaging using a rotating DC gradient has been explored and experimentally studied. Acoustic or sound noise has been one of the problems in examining patients, mainly due to the fast gradient pulsings in interaction with the main magnetic field. The sound noise has been noted to be proportionately louder as the magnetic field strength becomes larger. In this report, we describe a new imaging technique using a mechanically rotating DC gradient coil. The rotating DC gradient coil can effectively replace both phase encoding as well as readout gradient pulsings, and data obtained in this manner can provide a set of projection data that later can be used for projection reconstruction. With some interpolation techniques one can also perform conventional two-dimensional fast Fourier transform image reconstruction. The sound noise intensity compared with the conventional imaging technique, such as the spin-echo sequence, has been reduced down to about -20.7 dB or 117.5 times with this new technique. The experimental pulse sequence and its principle are described and images obtained by the new silent MR imaging technique are reported.

Cardioprotective effects of KR-30450, a novel K+(ATP) opener, and its major metabolite KR-30818 on isolated rat hearts

The cardiac effects of KR-30450 ((-)-(2R)-2-([1,3]-dioxolan-2-yl)-2-methyl-4-(2-oxopyrrolidin++ +-1-yl)-6-nitro-2H-1-benzopyran), a newly synthesized potassium channel activator, and its major metabolite KR-30818 ((-)-(2R)-2-hydroxymethyl-2-methyl-4-(2-oxopyrrolidin-1-yl)-6-nitr o-2H-1-benzopyran) were compared with those of lemakalim, a prototype of this class, in isolated globally ischemic rat hearts. KR-30450 and KR-30818 significantly improved reperfusion cardiac function (LVDP, left ventricular developed pressure; double product, LVDP x heart rate/1000), their potency being 5.2-fold and 0.7-fold greater than lemakalim (ED50 for recovering predrug double product: 0.10, 0.80 and 0.54 microM, respectively). KR-30450 and KR-30818 significantly attenuated reperfusion contracture and lactate dehydrogenase release with potency greater than and equal to lemakalim, respectively. They significantly increased time to contracture (TTC) during ischemia in a dose-dependent manner with a greater potency than lemakalim (EC25 for increasing TTC: 1.2, 2.1 and 3.2 microM, respectively). The protective effects of three compounds on the measured parameters were reversed by glyburide, a selective K+(ATP) blocker. In non-ischemic hearts, KR-30450 and lemakalim exerted weak negative inotropism at high concentrations and KR-30818 had no effects, whereas the three compounds significantly increased coronary flow at doses studied. Glyburide completely reversed preischemic cardiodepressant effects of these compounds but not their effects on coronary flow. In conclusion, KR-30450, a recently developed K+(ATP) opener, exerted more potent cardioprotective effects than lemakalim, and its major metabolite KR-30818 may play a significant role in its action in vivo.

On the Complexation of Cd(II) Ions with Polyacrylic Acid

Complexation of Cd(II) ions with polyacrylic acid has been studied potentiometrically and by 113Cd NMR spectroscopy. A Donnan model proposed by Marinsky (Marinsky, J. A., in "Ion Exchange and Solvent Extraction" (J. A. Marinsky and Y. Marcus, Eds.), Vol. 11, p. 237. Dekker, New York, 1993; Miyajima, T., in "Ion Exchange and Solvent Extraction" (J. A. Marinsky and Y. Marcus, Eds.), Vol. 12, p. 275. Dekker, New York, 1995) has been applied in order to correct for the electrostatic effect on the equilibria inherent in the polyelectrolyte nature of the polyions. The potentiometric studies showed that the bidentate ligand complex, (CdA2)0, is the dominant species, but the formation of monodentate ligand complex, (CdA)+, cannot be neglected at low degree of dissociation of the polyacid. The stability constants of the (CdA)+ and (CdA2)0 complexes have been determined to be approximately 3.2 x 10 and 1.6 x 10(2), respectively. These values are in good agreement with the stability constants of 4.1 x 10 and 1.0 x 10(2) for Cd(acetate) and Cd(glutarate) complexes, where acetate and glutarate ions are the monomer analog ligands of polyacrylic acid. The 113Cd NMR chemical shift change upon dissociation of the polyacid also indicates that the dominant complex is (CdA2)0, but (CdA)+ becomes more appreciable with the decreasing degree of dissociation of the polyacid.

Pharmacokinetic changes of methotrexate after intravenous administration to uranyl nitrate-induced acute renal failure rats

The pharmacokinetic changes of methotrexate (MTX) were investigated after 1-min intravenous (iv) administration of MTX, 8 mg/kg, to the control and the uranyl nitrate-induced acute renal failure (U-ARF) rats. The impaired kidney and liver functions were observed by pretreatment with urinary nitrate based on physiological parameters of plasma and urine, and the tissue microscopy. After 1-min iv infusion of MTX, the plasma concentrations of MTX (except at 1 min) and the total area under the plasma concentration-time curves of MTX (542 versus 297 micrograms min/ml) increased significantly in the U-ARF rats when compared to those in the control rats. This was due to the significantly slower in total body clearance (CL) of MTX (15.2 versus 27.5 ml/min/kg) in the U-ARF rats than that in the control rats. The significantly slower in CL of MTX in the U-ARF rats was due to the significantly slower both renal (1.01 versus 8.39 ml/min/kg, because of the considerably decreased renal tubular secretion of MTX) and nonrenal (14.2 versus 19.1 ml/min/kg, because of the considerably decreased liver metabolism) clearances in the U-ARF rats. All 11 control rats survived until sacrificed (24 h), however, 5 out of 15 U-ARF rats died within 7 h after iv administration of MTX. If the present rat data were to be extrapolated to human beings, iv dose of MTX need to be modified in the acute renal failure patients.

Pharmacokinetic changes of methotrexate after intravenous administration to streptozotocin-induced diabetes mellitus rats

The pharmacokinetic changes of methotrexate (MTX) were investigated after 1-min intravenous (iv) administration of MTX, 8 mg/kg, to the control and the streptozotocin-induced diabetes mellitus (SIDM) rats. After 1-min iv infusion of MTX, plasma concentrations of MTX declined polyexponentially for both groups of rats. In the SIDM rats, the plasma concentrations of MTX were significantly lower up to 5 min, however, significantly higher from 60 min than those in the control rats. In the SIDM rats, the volume of distribution at steady state was significantly higher (1010 versus 265 ml/kg) than that in the control rats, and this was due to the significantly increased unbound fraction of MTX (73.0 versus 58.1%) in serum of SIDM rats. This resulted in a significantly increased mean residence time (53.2 versus 13.8 min) in the SIDM rats. All 12 control rats survived until sacrificed (24 hr), however, 6 out of 15 SIDM rats died within 6 h after iv administration of MTX, suggesting that the iv doses of MTX in diabetes mellitus patients may need to be modified if the present rat data could be extrapolated to human beings.

Demonstration of the second intermediate hosts of Clinostomum complanatum in Korea

A species of metacercariae recovered from the fresh-water fish, collected from Kaumji (Pond), Kaechonji (Pond) and Ssanggyechon (River). Uisong-gun, Kyongsangbuk-do, Korea, was identified as Clinostomum complanatum by morphological observation and experimental infection to chicks. The excysted metacercariae, tongue-shaped and progenetic, were 3.28-4.27 mm in length and 0.94-1.46 mm in width. The adult flukes recovered from the chicks four days after infection were 4.20-4.86 mm long and 1.14-1.49 mm wide. Twelve species of the fresh-water fish were found to be infected with the metacercariae. The infection rate ranged from 1.6% (Zacco temminkii) to 88.9% (Acheilognathus rhombea and Microphysogobio yaluensis). The intensity was highest in Carassius auratus (13.0/fish infected) and the abundance (relative density) was highest in A. rhombea (7.8/fish examined). This survey demonstrated for the first time the source of human infection by C. complanatum in Korea.

The first human case of Diplogonoporus balaenopterae (Cestoda: Diphyllobothriidae) infection in Korea

The first human case of Diplogonoporus balaenopterae infection is reported in Korea. The patient was a 41-year old male who passed a part of cestode strobila, about 1 m long, spontaneously in his stool. He used to eat raw marine fish when he drank alcohol. The worm was identified as D. balaenopterae after morhological observations and literature review. Results of laboratory examination were within normal limits except for slight eosinophilia (6%) and extraordinarily high serum Ig E level (10,182 IU/ml).

The first human case of Clinostomum complanatum (Trematoda: Clinostomidae) infection in Korea

The authors present the first human case of Clinostomum pharyngitis in Taegu, Korea. The patient was a 56-year old male who visited an otolaryngology clinic due to foreign body sensation and pain of the pharyngeal region for 3-4 days. He used to eat raw fresh-water fish. Otolaryngological examinations revealed a living worm adhered to the right posterior pharyngeal wall. The worm removed was identified as C. complanatum after morphological observations. It is likely that more attention should be paid to eating raw fresh-water fish in Korea with regards to Clinostomum pharyngitis.

Staurosporine induces de novo synthesis of prostaglandin H synthase-2 in rat alveolar macrophages

This study was initiated to investigate the possible involvement of prostaglandin H synthase in the staurosporine-induced prostaglandin production. The time course of prostaglandin H synthase activity in macrophages treated with staurosporine (20 nM) showed that the maximum activity was reached in 20 h. The stimulatory effect of staurosporine on thromboxane B2 production was maximum at 50 nM staurosporine and this effect was reversed at higher concentrations. Immunoprecipitation of 35S-labeled enzyme using an antibody specific for prostaglandin H synthase-2 paralleled the changes in enzyme activity. These results indicate that increased de novo synthesis of prostaglandin H synthase-2 is largely, if not solely, responsible for staurosporine-stimulated prostaglandin production in macrophages.

Continuous determination of extracellular space and changes of K+, Na+, Ca2+, and H+ during global ischaemia in isolated rat hearts

Isolated rat hearts were perfused according to the Langendorff technique and prepared to allow the measurement of left ventricular pressure (LVP), the first derivative of LVP (dP/dt), coronary perfusion pressure (CPP) and heart rate (HR). The hearts were perfused with a modified Krebs-Henseleit solution (KHS; control group) or KHS containing tetramethylammonium-chloride (TMA; 100 microM), which did not influence heart haemodynamics or extracellular potassium accumulation during global ischaemia (GI). TMA was used as a marker to determine changes in the size of the extracellular space (ECS) during 60 min of GI. Extracellular concentrations of K+, Na+, Ca2+, H+ and TMA were measured using double-barreled polyvinyl chloride (PVC) mini-electrodes. Relative changes in the ECS size and net cation movements were calculated from the extracellular TMA and cation concentrations. After 60 min of GI ECS decreased by 74% due to a water shift into the intracellular space (ICS). Within 10 s after the onset of GI extracellular potassium concentration increased in a typical triphasic pattern. A biphasic net efflux of K+ was maximal 2 and 15 min after the onset of ischaemia interrupted by a maximal uptake after 7 min, probably due to the stimulation of the Na+/K+ ATPase. The changes in extracellular sodium and calcium concentrations were biphasic; showing an initial increase occurring approximately during the first 20 min after the onset of GI followed by a decrease. Despite the initial increase of extracellular Na+ and Ca2+ maximal net influx of Na+ and Ca2+ were calculated after 2 and 19 min of GI. Accumulation of H+ in the extracellular space occurred mainly during the first 20 min of GI. It is concluded that, (1) TMA is a useful marker for continuous measurement of changes in the size of the ECS during GI; (2) Changes in extracellular ion concentration are influenced markedly by a water shift from the ECS into the ICS; (3) Stimulation of the Na+/K+ pump causes a transient net uptake of K+ and reduces the net influx of Na+; (4) Ca2+ uptake is decreased transiently probably by increased Ca2(+)-ATPase activity; (5) Energy dependent protective mechanisms for the maintainance of intracellular ionic homeostasis are exhausted after approximately 15 to 20 min of GI in isolated working rat hearts.

Pharmacokinetics of N-propylajmaline in relation to polymorphic sparteine oxidation

In order to determine whether the metabolism of the antiarrhythmic drug N-propylajmaline is under the same genetic control as sparteine metabolism, the pharmacokinetics of this antiarrhythmic drug were studied in a groups of six extensive and four poor metabolizers of sparteine. Pronounced differences in terminal half-life, total plasma clearance, metabolic clearance and urinary excretion of N-propylajmaline were observed between extensive and poor metabolizers. A close relationship between the total clearance and metabolic clearance of N-propylajmaline and sparteine could be demonstrated. Clinically available N-propylajmaline is a 55% to 45% mixture of the i- and n-diastereomers. The extensive metabolizers exhibited stereoselective metabolism; the i-diastereomer was preferentially metabolized. Poor metabolizers were characterized by a loss of this stereoselective metabolism. Five subjects were treated for 7 days with a daily N-propylajmaline dosage of either 60 mg or 20 mg. Since a close relationship between the clearance of N-propylajmaline and the metabolic ratio of sparteine had been observed after single dosing the metabolic ratio of sparteine was used to predict N-propylajmaline steady-state plasma concentrations during multiple dosing. Only in two extensive metabolizers with a metabolic ratio less than 0.4 predicted and observed, steady-state plasma concentrations were in good agreement. In the other three subjects observed steady-state plasma concentrations were appreciably higher than predicted. In these three subjects metabolic N-propylajmaline clearance decreased indicating saturation N-propylajmaline metabolism during multiple dosing. The data indicate that N-propylajmaline metabolism is subject to a genetic polymorphism controlled by the sparteine/debrisoquine gene locus.