Effects and Limitations of Naldemedine for Opioid-Induced Urinary Retention: A Case Report

A 78-year-old man with postoperative recurrence of esophageal cancer was admitted to the hospital due to chest pain and dyspnea. Oral short-acting opioids provided some relief, but chest pain persisted and worsened, leading to the initiation of a transdermal fentanyl patch. However, the patient developed opioid-induced urinary retention, which was treated with a naldemedine, a medication used for opioid-induced constipation and urinary retention. Opioid switching led to recurrent urinary retention, requiring placement of a urinary catheter. The patient ultimately required continuous deep sedation for refractory symptoms and died several days later.

Dynamic behaviour of the soft palate during nasal positive pressure ventilation under anaesthesia and paralysis: comparison between patients with and without obstructive sleep-disordered breathing

BACKGROUND

Difficult mask ventilation is common and is known to be associated with sleep-disordered breathing (SDB). It is our hypothesis that the incidence of expiratory retropalatal (RP) airway closure (primary outcome) during nasal positive pressure ventilation (PPV) is more frequent in patients with SDB (apnea hypopnea index ≥5 h^-1) than non-SDB subjects.

METHODS

The severity of SDB was assessed before surgery using a portable sleep monitor. In anaesthetized and paralysed patients with (n=11) and without SDB (n=9), we observed the behaviour of the RP airway endoscopically during nasal PPV with the mouth closed and determined the dynamic RP closing pressure, which was defined as the highest airway pressure above which the RP airway closure was reversed. The static RP closing pressure was obtained during cessation of mechanical ventilation in patients with dynamic RP closure during nasal PPV.

RESULTS

The expiratory RP airway closure accompanied by expiratory flow limitation occurred more frequently in SDB patients (9/11, 82%) than in non-SDB subjects (2/9, 22%; exact logistic regression analysis: P=0.022, odds ratio 3.6, 95% confidence interval 1.1-15.4). Receiver operating characteristic curve analyses indicated AHI >10h^-1 and presence of habitual snoring as clinically useful predictors for the occurrence of RP closure during PPV. Dynamic RP closing pressure was greater than the static RP closing pressure by approximately 4-5 cm H₂O.

CONCLUSIONS

Valve-like dynamic RP closure that limits expiratory flow during nasal PPV occurs more frequently in SDB patients.

A cluster of interferon-γ-inducible p65 GTPases plays a critical role in host defense against Toxoplasma gondii

Interferon-γ (IFN-γ) is essential for host defense against intracellular pathogens. Stimulation of innate immune cells by IFN-γ upregulates ∼2,000 effector genes such as immunity-related GTPases including p65 guanylate-binding protein (Gbp) family genes. We show that a cluster of Gbp genes was required for host cellular immunity against the intracellular parasite Toxoplasma gondii. We generated mice deficient for all six Gbp genes located on chromosome 3 (Gbp(chr3)) by targeted chromosome engineering. Mice lacking Gbp(chr3) were highly susceptible to T. gondii infection, resulting in increased parasite burden in immune organs. Furthermore, Gbp(chr3)-deleted macrophages were defective in IFN-γ-mediated suppression of T. gondii intracellular growth and recruitment of IFN-γ-inducible p47 GTPase Irgb6 to the parasitophorous vacuole. In addition, some members of Gbp(chr3) restored the protective response against T. gondii in Gbp(chr3)-deleted cells. Our results suggest that Gbp(chr3) play a pivotal role in anti-T. gondii host defense by controlling IFN-γ-mediated Irgb6-dependent cellular innate immunity.

The impact of childhood abuse history, domestic violence and mental health symptoms on parenting behaviour among mothers in Japan

BACKGROUND

To assess the impact of childhood abuse history, domestic violence experiences and mental health symptoms on the parenting behaviour of mothers in Japan who have separated from violent husbands or partners.

METHODS

A self-administered questionnaire survey was conducted on a sample of mothers (n = 304) and their children (n = 498) residing in 83 mother-child homes in Japan. The survey assessed the mothers' childhood abuse history (physical, psychological and sexual abuse and neglect history), domestic violence experiences, current mental health symptoms (dissociative, depressive and traumatic symptoms) and parenting behaviours after moving into the homes to separate from a violent husband or partner.

RESULTS

The mothers' childhood abuse history and experience of domestic violence were not associated with their not playing with their children. In contrast, the mothers' dissociative and depressive symptoms were significantly associated with not playing with their children. Although there was no association between the mothers' total childhood abuse history and not praising their children, their childhood physical abuse history was significantly associated with their not praising their children. The dissociative and depressive symptoms were also associated with no praise. Interestingly, the experience of domestic violence showed an inverse association with no praise.

CONCLUSIONS

Mental health symptoms, more specifically dissociative and depressive symptoms, are associated with a decrease in parenting quality. Mothers who were physically abused as children are less likely to praise their own children, independent of maternal mental health symptoms. In contrast, mothers who experienced domestic violence but subsequently separated from their violent husbands or partners are more likely to praise their children. The treatment of mental health symptoms, particularly dissociative and depressive symptoms, therapy for childhood abuse history and separation from violent husbands or partners might be effective ways to enhance the quality of parenting in Japan.

[Factors and prosesses associated with weight loss in male workers in a specific health guidance program. A qualitative analysis of in-depth interviews]

OBJECTIVES

A qualitative analysis was conducted to identify factors important for weight loss through a specific health guidance program and to understand the processes that were crucial in achieving success.

METHODS

Twenty-six male workers aged 41-59 years from five corporate health insurance societies in four prefectures who had lost > or = 4% weight by attending the six-month specific health guidance program were invited to participate in the in-depth interviews. Data were collected between October and December 2009. We audio taped the 30-minute interviews and performed qualitative analysis on the transcripts using a grounded theory. The discussion by the expert panel strengthened the validity of the analysis.

RESULTS

The mean age was 49.9 +/- 5.6 years, and the average weight loss was 6.8 +/- 2.5%. All subjects were somewhat concerned about their health status and body shape before the first appointment, but two major prosesses, "critical feeling" and "sense of obligation," were identified after the first appointment. We also identified innovative efforts in all subjects during the process. Those who reported a "sense of obligation" at the beginning and those who had a negative perception during the program were found to have higher risks of weight rebound after the program was over. We considered personality, values, attitudes toward the program, and support from both family and workplace as the intervening conditions for behavior modification.

CONCLUSION

Since everyone aged 40-74 years with a certain risk of metabolic syndromes is obligated by law to participate in the specific health guidance program, weight loss is challenging for those who are not motivated enough to change their behaviors. Therefore, the initial assessment of one's motivations, followed by interventions taken in consideration of one's lifestyle and social background, are crucial for the success of a weight loss program, as is the use of a client-centered approach.

ATF6beta is a host cellular target of the Toxoplasma gondii virulence factor ROP18

Toxoplasma virulence factor ROP18 targets endoplasmic reticulum–bound transcription factor ATF6β in the host cell, leading to the detrimental loss of ATF6β through proteasome-dependent degradation.

The ROP18 kinase has been identified as a key virulence determinant conferring a high mortality phenotype characteristic of type I Toxoplasma gondii strains. This major effector molecule is secreted by the rhoptries into the host cells during invasion; however, the molecular mechanisms by which this kinase exerts its pathogenic action remain poorly understood. In this study, we show that ROP18 targets the host endoplasmic reticulum–bound transcription factor ATF6β. Disruption of the ROP18 gene severely impairs acute toxoplasmosis by the type I RH strain. Because another virulence factor ROP16 kinase modulates immune responses through its N-terminal portion, we focus on the role of the N terminus of ROP18 in the subversion of host cellular functions. The N-terminal extension of ROP18 contributes to ATF6β-dependent pathogenicity by interacting with ATF6β and destabilizing it. The kinase activity of ROP18 is essential for proteasome-dependent degradation of ATF6β and for parasite virulence. Consistent with a key role for ATF6β in resistance against this intracellular pathogen, ATF6β-deficient mice exhibit a high susceptibility to infection by ROP18-deficient parasites. The results reveal that interference with ATF6β-dependent immune responses is a novel pathogenic mechanism induced by ROP18.

A novel in vivo inducible dendritic cell ablation model in mice

Dendritic cells (DCs) are involved in T cell activation via their uptake and presentation of antigens. In vivo function of DCs was analyzed using transgenic mouse models that express diphtheria toxin receptor (DTR) or the diphtheria toxin-A subunit (DTA) under the control of the CD11c/Itgax promoter. However, CD11c+ cells are heterogeneous populations that contain several DC subsets. Thus, the in vivo function of each subset of DCs remains to be elucidated. Here, we describe a new inducible DC ablation model, in which DTR expression is induced under the CD11c/Itgax promoter after Cre-mediated excision of a stop cassette (CD11c-iDTR). Crossing of CD11c-iDTR mice with CAG-Cre transgenic mice, expressing Cre recombinase under control of the cytomegalovirus immediate early enhancer-chicken beta-actin hybrid promoter, led to the generation of mice, in which DTR was selectively expressed in CD11c+ cells (iDTRDelta mice). We successfully deleted CD11c+ cells in bone marrow-derived DCs in vitro and splenic CD11c+ cells in vivo after DT treatment in iDTRDelta mice. This mouse strain will be a useful tool for generating mice lacking a specific subset of DCs using a transgenic mouse strain, in which the Cre gene is expressed by a DC subset-specific promoter.

A single polymorphic amino acid on Toxoplasma gondii kinase ROP16 determines the direct and strain-specific activation of Stat3

Infection by Toxoplasma gondii down-regulates the host innate immune responses, such as proinflammatory cytokine production, in a Stat3-dependent manner. A forward genetic approach recently demonstrated that the type II strain fails to suppress immune responses because of a potential defect in a highly polymorphic parasite-derived kinase, ROP16. We generated ROP16-deficient type I parasites by reverse genetics and found a severe defect in parasite-induced Stat3 activation, culminating in enhanced production of interleukin (IL) 6 and IL-12 p40 in the infected macrophages. Furthermore, overexpression of ROP16 but not ROP18 in mammalian cells resulted in Stat3 phosphorylation and strong activation of Stat3-dependent promoters. In addition, kinase-inactive ROP16 failed to activate Stat3. Comparison of type I and type II ROP16 revealed that a single amino acid substitution in the kinase domain determined the strain difference in terms of Stat3 activation. Moreover, ROP16 bound Stat3 and directly induced phosphorylation of this transcription factor. These results formally establish an essential and direct requirement of ROP16 in parasite-induced Stat3 activation and the significance of a single amino acid replacement in the function of type II ROP16.

NFATc1 mediates Toll-like receptor-independent innate immune responses during Trypanosoma cruzi infection

Host defense against the intracellular protozoan parasite Trypanosoma cruzi depends on Toll-like receptor (TLR)-dependent innate immune responses. Recent studies also suggest the presence of TLR-independent responses to several microorganisms, such as viruses, bacteria, and fungi. However, the TLR-independent responses to protozoa remain unclear. Here, we demonstrate a novel TLR-independent innate response pathway to T. cruzi. Myd88^−/−Trif^−/− mice lacking TLR signaling showed normal T. cruzi-induced Th1 responses and maturation of dendritic cells (DCs), despite high sensitivity to the infection. IFN-γ was normally induced in T. cruzi-infected Myd88^−/−Trif^−/− innate immune cells, and further was responsible for the TLR-independent Th1 responses and DC maturation after T. cruzi infection. T. cruzi infection induced elevation of the intracellular Ca²⁺ level. Furthermore, T. cruzi-induced IFN-γ expression was blocked by inhibition of Ca²⁺ signaling. NFATc1, which plays a pivotal role in Ca²⁺ signaling in lymphocytes, was activated in T. cruzi-infected Myd88^−/−Trif^−/− innate immune cells. T. cruzi-infected Nfatc1^−/− fetal liver DCs were impaired in IFN-γ production and DC maturation. These results demonstrate that NFATc1 mediates TLR-independent innate immune responses in T. cruzi infection.

Trypanosoma cruzi is an intracellular protozoan parasite that causes Chagas diseases in humans. Invasion of T. cruzi into the host is sensed by Toll-like receptors (TLRs), which recognize microbial components that are present in microbes but not in the host. TLRs are essential for the initiation of immune responses against pathogens. Recent evidence indicates the presence of TLR-independent mechanisms for the recognition of microbes, such as bacteria, viruses, and fungi. However, TLR-independent recognition of protozoa remains unknown. We found that immune responses against T. cruzi were induced even in the absence of TLR signaling. The TLR-independent responses were found to be mediated by IFN-γ production in innate immune cells. Furthermore, the TLR-independent IFN-γ production was revealed to be mediated by Ca²⁺-dependent activation of NFATc1, which has been shown to play a pivotal role in cytokine production in T lymphocytes. Our study provides a novel mechanism for the TLR-independent innate immune response against protozoan parasites. It is also worth noting that the host defense mechanism utilizes a factor (Ca²⁺) that is a prerequisite for the survival of intracellular protozoan parasites.

Lipocalin 2-dependent inhibition of mycobacterial growth in alveolar epithelium

Mycobacterium tuberculosis invades alveolar epithelial cells as well as macrophages. However, the role of alveolar epithelial cells in the host defense against M. tuberculosis remains unknown. In this study, we report that lipocalin 2 (Lcn2)-dependent inhibition of mycobacterial growth within epithelial cells is required for anti-mycobacterial innate immune responses. Lcn2 is secreted into the alveolar space by alveolar macrophages and epithelial cells during the early phase of respiratory mycobacterial infection. Lcn2 inhibits the in vitro growth of mycobacteria through sequestration of iron uptake. Lcn2-deficient mice are highly susceptible to intratracheal infection with M. tuberculosis. Histological analyses at the early phase of mycobacterial infection in Lcn2-deficient mice reveal increased numbers of mycobacteria in epithelial cell layers, but not in macrophages, in the lungs. Increased intracellular mycobacterial growth is observed in alveolar epithelial cells, but not in alveolar macrophages, from Lcn2-deficient mice. The inhibitory action of Lcn2 is blocked by the addition of endocytosis inhibitors, suggesting that internalization of Lcn2 into the epithelial cells is a prerequisite for the inhibition of intracellular mycobacterial growth. Taken together, these findings highlight a pivotal role for alveolar epithelial cells during mycobacterial infection, in which Lcn2 mediates anti-mycobacterial innate immune responses within the epithelial cells.

122 GLYCOSAMINOGLYCANS IMPROVE THE NUMBER OF BLASTOMERES IN ZONA-FREE RAT AND MOUSE EMBRYOS

In general, early mammalian embryos are enclosed by zona pellucida until the blastocyst stage. The possible role of zona pellucida could be to maintain the three-dimensional structure of cleaving embryos, as well as preventing blastomeres from attack by immune cells and miscellaneous germs. However, beneficial roles of the zona on early development of blastomeres are still unknown. The present study was undertaken to examine if the absence of zona pellucida of rat and mouse embryos at the 8-cell stage affected the early development to the blastocyst stage. Furthermore, we examined whether supplementation of culture medium with glycosaminoglycans, such as hyaluronic acid and heparan sulfate, improved the early development or not. In the first experiment, embryos at the 8-cell stage were collected from mated Wistar rats or ICR mice and then, directly or after removing zona pellucida by using acidity Tyrode’s solution, cultured in modified R1ECM or kSOM medium for 24 h in an atmosphere of 5% CO2 in air. Following culture, the incidence of blastocyst formation and the cell number of blastocysts were examined. In the second experiment, intact or zona-free 8-cell embryos were cultured in various concentration of hyaluronic acid (0, 65, 125, 250 μg mL–1) or heparin sulfate (0 or 15 μg mL–1) for 24 h. After culture, blastocyst formation and cell number of blastocyst were similarly examined. Statistical analyses was performed by one-way ANOVA with Bonferroni/Dunn’s post hoc test (significance, P < 0.05). All percentage data were subjected to arc-sine transformation before statistical analysis. Percentage of blastocyst formation and the mean cell number of the blastocyst were less when zona-free 8-cell rat and mouse embryos were cultured (72.1 ± 2.9% and 22.8 ± 0.7), as compared with control intact embryos (94.3 ± 3.5% and 30.6 ± 1.1). Supplementation with hyaluronic acid (250 μg mL–1) improved the blastocyst formation rate of rat embryos (86.4 ± 5.0%) and the cell number of blastocysts (28.8 ± 0.5) to the same level of zona-intact embryos. In mouse embryos, the same concentration of hyaluronic acid improved only the cell number of blastocysts (from 21.7 ± 0.7 to 28.9 ± 0.7) to the same level of zona-intact embryos (30.9 ± 0.7). When heparin sulfate was supplemented, the incidence of blastocyst formation of rat embryos did not improve, but the cell number of the blastocyst (31.1 ± 0.7) did improve to the similar level with zona-intact embryos (30.6 ± 1.1). These results indicate that the zona pellucida has a beneficial effect on the early development of rat and mouse embryos and suggest that glycosaminoglycans, such as hyaluronic acid and heparan sulfate, contribute to the beneficial effect.

Vascular pharmacology of a novel cannabinoid-like compound, 3-(5-dimethylcarbamoyl-pent-1-enyl)-N-(2-hydroxy-1-methyl-ethyl)benzamide (VSN16) in the rat

BACKGROUND AND PURPOSE

A putative novel cannabinoid receptor mediates vasorelaxation to anandamide and abnormal-cannabidiol and is blocked by O-1918 and by high concentrations of rimonabant. This study investigates VSN16, a novel water-soluble agonist, as a vasorelaxant potentially acting at non-CB1, non-CB2 cannabinoid receptors in the vasculature.

EXPERIMENTAL APPROACH

VSN16 and some analogues were synthesized and assayed for vasodilator activity in the rat third generation mesenteric artery using wire myography. Also carried out with VSN16 were haemodynamic studies in conscious rats and binding studies to CB1 receptors of rat cerebellum.

KEY RESULTS

VSN16 relaxed mesenteric arteries in an endothelium-dependent manner. The vasorelaxation was antagonized by high concentrations of the classical cannabinoid antagonists, rimonabant and AM 251, as well as by O-1918, an antagonist at the abnormal-cannabidiol receptor but not at CB1 or CB2 receptors. It did not affect [3H]CP55,940 binding to CB1 receptors in rat cerebellum. The vasorelaxation was not pertussis toxin-sensitive but was reduced by inhibition of nitric oxide synthesis, Ca(2+)-sensitive K+ channels (KCa) and TRPV1 receptors. In conscious rats VSN16 transiently increased blood pressure and caused a longer-lasting increase in mesenteric vascular conductance. Structure-activity studies on vasorelaxation showed a stringent interaction with the target receptor.

CONCLUSIONS AND IMPLICATIONS

VSN16 is an agonist at a novel cannabinoid receptor of the vasculature. It acts on the endothelium to release nitric oxide and activate KCa and TRPV1. As it is water-soluble it might be useful in bringing about peripheral cannabinoid-like effects without accompanying central or severe cardiovascular responses.

Control of cell wall assembly by a histone-like protein in Mycobacteria

Bacteria coordinate assembly of the cell wall as well as synthesis of cellular components depending on the growth state. The mycobacterial cell wall is dominated by mycolic acids covalently linked to sugars, such as trehalose and arabinose, and is critical for pathogenesis of mycobacteria. Transfer of mycolic acids to sugars is necessary for cell wall biogenesis and is mediated by mycolyltransferases, which have been previously identified as three antigen 85 (Ag85) complex proteins. However, the regulation mechanism which links cell wall biogenesis and the growth state has not been elucidated. Here we found that a histone-like protein has a dual concentration-dependent regulatory effect on mycolyltransferase functions of the Ag85 complex through direct binding to both the Ag85 complex and the substrate, trehalose-6-monomycolate, in the cell wall. A histone-like protein-deficient Mycobacterium smegmatis strain has an unusual crenellated cell wall structure and exhibits impaired cessation of glycolipid biosynthesis in the growth-retarded phase. Furthermore, we found that artificial alteration of the amount of the extracellular histone-like protein and the Ag85 complex changes the growth rate of mycobacteria, perhaps due to impaired down-regulation of glycolipid biosynthesis. Our results demonstrate novel regulation of cell wall assembly which has an impact on bacterial growth.

Sound spectrogram analysis in patients receiving Kawahara's surgical voice restoration for advanced carcinoma of the hypopharynx and cervical esophagus

Loss of voice after total laryngectomy is a major concern that has prompted much effort to develop methods of surgical voice restoration. In 1992, Kawahara described a tracheocolic shunt for voice restoration using a revascularized ileocolic graft. With this method, aspiration through the phonatory shunt is prevented by the ileocolic valve (Bauhin's valve), while vocalization is allowed. The purpose of this study was to use sound spectrogram analysis to evaluate voices surgically restored in that way. Between 2002 and 2005, 10 consecutive patients underwent laryngopharyngoesophagectomy with Kawahara's surgical voice restoration for advanced carcinoma of the hypopharynx and/or cervical esophagus at Akita University Hospital, Japan. We then used sound spectrography to analyze and compare the voices of patients receiving Kawahara's voice restoration, against healthy volunteers and patients who underwent the same surgery without voice restoration and spoke using an electronic larynx. We also evaluated the intelligibility of conversation and performed a listening test. The sound spectrograms showed that when produced by the electronic larynx, consonant sounds and voice frequencies below 300 Hz were not clearly recognized. By contrast, in patients who received Kawahara's surgical voice restoration, consonant and vowel sounds at frequencies above and below 300 Hz were clearly recognized. Although conversation was intelligible with both Kawahara's surgical voice restoration and the electronic device, listeners judged the voice produced by the former to be superior. Thus, the voice produced by Kawahara's surgical voice restoration is superior to that produced by the electronic larynx.

Extravascular Lung Water Measured Using Single Transpulmonary Thermodilution Reflects Perioperative Pulmonary Edema Induced by Esophagectomy

Pulmonary edema is the most frequent postoperative complication following esophagectomy for thoracic esophageal cancer. We enrolled 23 patients who underwent esophagectomy with extended lymph node dissection for thoracic esophageal cancer in a prospective observational clinical trial. We used the PiCCO device to measure extravascular lung water with the aim of determining whether it correlates with the respiratory index and whether it is predictive of pulmonary complications. Based on constant criteria, the tracheal tubes of 11 patients were removed on the morning of postoperative day 1 (extubation group), while 12 patients remained intubated (intubation group). These two groups significantly differed in that all patients in the extubation group recovered without any pulmonary complications, whereas 4 patients (33%) in the intubation group developed pulmonary complications. The extravascular lung water measured using PiCCO correlated significantly with the respiratory index. In the intubation group, both extravascular lung water and respiratory index were elevated 12 h after surgery and were even higher 24 h after surgery. The extravascular lung water measured using PiCCO reflects the level of postoperative pulmonary edema and predicts the pulmonary complications induced by esophagectomy with extended lymph node dissection.

Roles of cyclooxygenase 2 and microsomal prostaglandin E synthase 1 in rat acid reflux oesophagitis

BACKGROUND

Although prostaglandin E2 (PGE2), cyclooxygenase 2 (COX-2), and microsomal prostaglandin E synthase 1 (mPGES-1) are known to play a role in various inflammatory events, their roles in the pathogenesis of gastro-oesophageal reflux disease are not known.

AIMS

We examined the dynamics of COX-1, COX-2, mPGES-1, mPGES-2, cytosolic PGES (cPGES), and PGE2 synthetic activity in rat acid reflux oesophagitis and the effects of COX-2 inhibitors on the severity of oesophagitis.

METHODS

Acid reflux oesophagitis was induced by ligating the transitional region between the forestomach and the glandular portion and wrapping the duodenum near the pylorus. Rats were killed on day 3 (acute phase) or day 21 (chronic phase) after induction of oesophagitis.

RESULTS

Expression of COX-2 and mPGES-1 was markedly increased in oesophagitis while modest changes in COX-1, cPGES, and mPGES-2 expression were observed. COX-2 and mPGES-1 were colocalised in epithelial cells of the basal layer, as well as inflammatory and mesenchymal cells in the lamina propria and submucosa. COX-2 inhibitors significantly reduced the severity of chronic oesophagitis but did not affect acute oesophageal lesions. COX-2 inhibitors significantly inhibited the increase in PGE2 synthesis in oesophageal lesions on both days 3 and 21. Epithelial proliferation was significantly increased in the basal layer on day 21. Inflammatory cells and epithelial cells of the basal layer exhibited reactions for EP4 in oesophagitis.

CONCLUSION

PGE2 derived from COX-2 and mPGES-1 plays a significant role in the pathogenesis of chronic acid reflux oesophagitis, and possibly in basal hyperplasia and persistent inflammatory cell infiltration.

Carbonate-containing hydroxyapatite derived from calcium tripolyphosphate gel with urea

Carbonate containing hydroxyapatite (CO3HAp) is one of the candidate materials as a bioresorbable bone substitute. In the present work, CO3HAp was efficiently prepared by a hydrothermal treatment of calcium tripolyphosphate gel with urea at 140 degrees C for 24 h. Chemical potential plots of the CO3HAp for estimation of its dissolution behavior suggested that the CO3HAp is more soluble than hydroxyapatite (HAp) and is as soluble as octacalcium phosphate (OCP) and/or beta -tricalcium phosphate (TCP). This material is expected to be applied to bioresorbable materials such as bone fillers.

Pulsed Doppler tissue imaging for the assessment of myocardial viability: comparison with 99mTc sestamibi perfusion imaging

The aim of the present study was to examine whether Doppler tissue imaging demonstrated comparable diagnostic performance for the detection of viable myocardium compared to myocardial perfusion imaging with Tc hexakis-2-methoxyisobutylisonitrile (MIBI). We studied 30 patients with old myocardial infarction who underwent percutaneous transluminal coronary angioplasty (PTCA). Myocardial single photon emission computed tomography (SPECT) with Tc-MIBI and two-dimensional echocardiography were carried out within 7 days before PTCA. We measured regional Tc-MIBI uptake for each myocardial segment from SPECT and peak systolic velocity and a ratio of regional pre-ejection period to regional ejection time (PEP/ET) from pulsed Doppler tissue imaging. Biplane left ventriculography was performed before interventional procedures and repeated 3 months after PTCA. Myocardial viability was determined when wall motion was improved at least one grade after PTCA. The peak systolic velocity was positively correlated with regional Tc-MIBI uptake (R =0.59, P<0.01). The PEP/ET demonstrated inverse correlation with Tc-MIBI uptake ( R=-0.59, P<0.01). Peak systolic velocity of viable segments was higher than that of non-viable segments ( P<0.05). The PEP/ET was lower in viable segments than in non-viable segments ( P<0.05). Peak systolic velocity and PEP/ET demonstrated high diagnostic accuracy for detecting viable myocardium compared with Tc-MIBI perfusion imaging (80% and 79% vs 90%). These data indicate that measurements of regional peak systolic velocity and PEP/ET by Doppler tissue imaging are useful for evaluating myocardial viability quantitatively and provide helpful information for a clinical judgment in an interventional strategy.

Purification and identification of the essential ionizable groups of honeybee, Apis mellifera L., trehalase

Trehalase (EC 3.2.1.28) of the bound type was purified as an electrophoretically homogeneous protein from adult honeybees by fractionation with ammonium sulfate, hydrophobic chromatography, and DEAE-Sepharose CL-6B, CM-Sepharose CL-6B, butyl-Toyopearl 650M, and p-aminophenyl beta-glucoside Sepharose 4B column chromatographies. The enzyme preparation was confirmed to be a monomeric protein containing 3.1% carbohydrate. The molecular weight was estimated to be approximately 69,000, and the optimum pH was 6.7. The Michaelis constant (Km) was 0.66 mM, and the molecular activity (k0) was 86.2 s(-1). The enzyme was an "inverting" type which produced beta-glucose from alpha, alpha-trehalose. Dependence of the V and Km values on pH gave values for the ionization constants, pKe1 and pKe2, of essential ionizable groups 1 and 2 of the free enzyme of 5.3 and 8.5, respectively. When the dielectric constant of the reaction mixture was decreased, pKe1, and pKe2 were shifted to higher values of + 0.2 and + 0.5 pH unit, respectively. The ionization heat (deltaH) of ionizable group 1 was estimated to be + 1.8 kcal/mol, and the deltaH value of group 2 was + 1.5 kcal/mol. These findings strongly support the notion that the essential ionizable groups of honeybee trehalase are two kinds of carboxyl groups, one being a dissociated type (-COO(-), ionizable group 1) and the other a protonated type (-COOH, ionizable group 2), although the pKe2 value is high.

Reverse redistribution of 99m Tc-sestamibi after direct percutaneous transluminal coronary angioplasty in acute myocardial infarction: relationship with wall motion and functional response to dobutamine stimulation

Reverse redistribution (RR) of 99mTc-sestamibi is observed after direct percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction (AMI). The purpose of this study was to clarify the functional characteristics of myocardial segments with RR after direct PTCA in AMI. Thirty patients with AMI who had undergone direct PTCA were examined. Myocardial perfusion tomography with 99mTc-sestamibi and low dose dobutamine echocardiography were performed within 2 weeks of the onset. The 99mTc-sestamibi images were obtained 1 and 3 h after tracer administration. The left ventricle was divided into nine segments, and regional 99mTc-sestamibi uptake and clearance were quantitatively evaluated in each segment. RR was defined as a decrease in 99mTc-sestamibi uptake of >10% on 3 h delayed images compared with the 1 h early images. The left ventricle in the echocardiographic images was also divided into nine segments corresponding to the scintigraphic images, and regional wall motion was assessed in the resting condition as the baseline and during dobutamine administration (5-10 microg x kg(-1) x min(-1)). Out of a total of 270 myocardial segments, 111 segments were perfused by the culprit coronary artery and were defined as ischaemic segments. There were 25 segments with RR and 86 segments without RR in the ischaemic myocardium. Enhanced clearance of 99mTc-sestamibi was observed in ischaemic segments with RR (P<0.001). Echocardiography demonstrated that 24 out of 25 segments with RR and 61 out of 86 segments without RR had wall motion abnormalities. Dobutamine infusion improved wall motion in 20 (83%) of the 24 dysfunctional segments with RR and 33 (54%) of the 61 dysfunctional segments without RR (P<0.02). These findings suggest that RR indicates reversible functional abnormalities associated with preserved contractile reserve in response to dobutamine. The early and delayed imaging of 99mTc-sestamibi provides useful information regarding the residual viability of the dysfunctional myocardium in AMI patients.

[Indication for surgical and microwave coagulation therapy for multiple (> or = 5) bilobar liver metastases from colorectal cancer]

We analyzed methods and clinicopathological factors for multiple (> or = 5) bilobar liver metastases (H3) from colorectal cancer and evaluated the indication of surgical and microwave coagulation therapy (MCT) for them. Twenty-four patients with H3 underwent surgical therapy and were divided into two groups. Group a: 9 patients with a prognosis of more than 700 days. Group b: the remaining 15 patients. There was no significant difference in prognosis between those receiving MCT and resection + MCT as a surgical therapy. The number and maximum diameter of tumors tended to be smaller in Group a. The number of tumors was less than or equal to 9 and the maximum size of the tumors was 38 mm. Moreover, the tumor could be controlled by MCT alone if the tumor size was less than 30 mm. MCT is a useful therapy for these cases and the indication for surgical therapy may depend on the number and maximum size of tumors.

[Comparison of microwave coagulation using a new type electrode with radiofrequency ablation in the liver of living animals]

In the present study, we compared microwave coagulation using a new type of electrode, a teflon-coated electrode that was developed in order to increase the area of coagulation, with radiofrequency ablation using a Radionics Cool-tip electrode inserted into the pig liver. Two Landrace male pig were put under general anesthesia. A microwave electrode (insulated area: 6 mm, teflon-coated electrode 16 G) and a radiofreqency (RF) electrode (Cool-tip RF single electrode 17 G) were passed through the surface of the livers of the pig. A thermometer was placed 1 cm from the tip of the electrode in order to measure the changes in the temperature of the area surrounding the electrode. In this study, the microwave setting was 80 W, and the RF pulse was set automatically. The coagulated and ablated areas of the liver were measured after 2.5, 5, and 10 minutes of energy delivery (n = 4). The diameter of the coagulated area of the liver following 2.5, 5 and 10 minutes of microwave exposure was 23.5 +/- 4.8 mm, 29.5 +/- 5.2 mm and 32.5 +/- 6.4 mm, respectively. On the other hand, the diameter of the ablated area of the liver following 2.5, 5 and 10 minutes of RF exposure was 18.5 +/- 4.1 mm, 24 +/- 7.8 mm and 28 +/- 4.9 mm, respectively. The mean temperature of the liver 1 cm from the microwave and RF electrodes (measured time: 2 minutes) was 69.6 degrees C and 56.3 degrees C. respectively (n = 12). Thus, the temperature of the area surrounding the microwave electrode was significantly higher than the temperature of the area surrounding the RF electrode (p = 0.0065). The teflon-coated microwave electrode achieved superior results to the Radionics Cool-tip electrode with respect to the diameter of the coagulated area and the temperature of the area in which the electrode was inserted, at the specified times.

Proliferative activity of the parathyroid cells in rats with secondary hyperparathyroidism

Proliferative kinetics of parathyroid cells in secondary hyperparathyroidism (HPT) are still unknown. We examined the histopathological changes and proliferative activity of parathyroid cells in spontaneously hypercholesterolemic (SHC) rats that exhibit secondary HPT and in normal Sprague Dawley (SD) rats from 3 weeks to 32 weeks of age. Proliferative activity [proliferating cell nuclear antigen(PCNA) labeling index], evaluated by means of immunohistochemical examination of PCNA, declined in SD rats with age from 10.8% at 3 weeks of age to 0.15% at 32 weeks of age. In SHC rats, a PCNA labeling index of 11.6% declined to 3.12% at 14 weeks of age and rebounded to 6.15% at 26 weeks of age. Parathyroid glands increased in size as determined by the maximum cross-sectional area, but in SHC rats, the increase was significantly greater, paralleling the progression of renal dysfunction, and at 32 weeks they were almost three times larger than in SD rats. Parathyroid hormone (PTH) levels in SHC rats also rose sharply after 20 weeks and reached 611 pg/ml at 32 weeks, while PTH in SD rats remained unchanged at approximately 110 pg/ml. This study showed that in the course of developing HPT in SHC rats, there is a large increase in the size of the parathyroid gland, a concomitant increase in PTH levels, and a PCNA labeling index that is higher than in normal SD rats.

Early stage of urolithiasis formation in experimental hyperparathyroidism

PURPOSE

We have previously noted marked acceleration in the proliferative activity of parathyroid cells in rats with spontaneous hypercholesterolemia and secondary hyperparathyroidism. Using this proliferative potential we investigated whether transplantation of these enlarged parathyroids into normal rats would induce hyperparathyroidism and renal stones.

MATERIALS AND METHODS

We used 26-week-old male rats with spontaneous hypercholesterolemia as donors, and 5-week-old normal male Sprague-Dawley rats and rats with spontaneous hypercholesterolemia as recipients. Enlarged parathyroid glands were transplanted into group 1--Sprague-Dawley rats with no treatment, group 2--Sprague-Dawley rats that received FK-506 as an immuno-suppressor, group 3--rats with spontaneous hypercholesterolemia rats that underwent parathyroidectomy plus FK-506 administration and group 4--Sprague-Dawley rats that underwent parathyroidectomy plus FK-506 administration. Parathyroidectomy was performed in recipients before transplantation to ensure a low calcium condition.

RESULTS

Grafts were rejected within 11 and 15 weeks in groups 1 and 2, respectively. In group 3, 78% of the grafts were successful even after 19 weeks. In group 4 graft survival was 30% at 15 weeks with complete rejection at 19 weeks. In group 3 gradually elevated serum parathyroid hormone was observed as well as stone plaques containing calcium oxalate and calcium phosphate in renal tubules located mainly in the corticomedullary junction. An increased number of plaques was associated with higher parathyroid hormone.

CONCLUSIONS

Our study shows that transplanted parathyroid glands function with an immunosuppressive agent and the maintenance of hypocalcemic conditions, and they secrete sufficient parathyroid hormone to demonstrate hyperparathyroidism. Plaque in these kidneys indicates an early stage of urolithiasis caused by hyperparathyroidism.

Carboxyl group of residue Asp647 as possible proton donor in catalytic reaction of alpha-glucosidase from Schizosaccharomyces pombe

cDNA encoding Schizosaccharomyces pombe alpha-glucosidase was cloned from a library constructed from mRNA of the fission yeast, and expressed in Saccharomyces cerevisiae. The cDNA, 4176 bp in length, included a single ORF composed of 2910 bp encoding a polypeptide of 969 amino-acid residues with M(r) 106 138. The deduced amino-acid sequence showed a high homology to those of alpha-glucosidases from molds, plants and mammals. Therefore, the enzyme was categorized into the alpha-glucosidase family II. By site-directed mutagenesis, Asp481, Glu484 and Asp647 residues were confirmed to be essential in the catalytic reaction. The carboxyl group (-COOH) of the Asp647 residue was for the first time shown to be the most likely proton donor acting as the acid catalyst in the alpha-glucosidase of family II. Studies with the chemical modifier conduritol B epoxide suggested that the carboxylate group (-COO-) of the Asp481 residue was the catalytic nucleophile, although the role of the Glu484 residue remains obscure.

Immunohistochemical expression of P-glycoprotein in the rat urinary bladder and the effect of verapamil on intravesical chemotherapy

BACKGROUND

The expression of P-glycoprotein (Pgp) is thought to be common in bladder epithelium and the multidrug resistance mediated by Pgp must be considered to improve the efficacy of chemotherapy for bladder tumors.

METHODS

The expression of Pgp in normal and tumor tissue of the rat urinary bladder was first examined immunohistochemically. The effect of verapamil, an expected modulator of Pgp, on intravesical chemotherapy of the rats was then investigated.

RESULTS

Pgp was immunohistochemically detected in normal epithelium and in tumor tissue of the rat urinary bladder. In those normal and tumor-bearing bladders, verapamil promoted the uptake of intravesically instilled pirarubicin, but the efflux of intracellular accumulated pirarubicin was observed subsequently in both conditions with and without verapamil. The drug concentration decreased more rapidly in the verapamil group than in the control group.

CONCLUSIONS

Verapamil is thought to be useful in promoting uptake of intravesically instilled pirarubicin, but it did not appear to be so efficient at limiting the efflux of intracellular accumulated pirarubicin.

Prednisolone suppresses ischemia-reperfusion injury of the rat liver by reducing cytokine production and calpain mu activation

BACKGROUND

We investigated the effects of prednisolone on cytokine production and calpain mu activation during hepatic ischemia-reperfusion (IR) injury.

METHODS

The hilar area of the left lateral and median lobes of rat liver was clamped for 60 min. Prednisolone was administered at 1.0, 3.0, or 10 mg/kg at 30 min before ischemia. In addition to biochemical and microscopic analyses, IL-beta and TNF-alpha production was evaluated by RT-PCR. Calpain mu activation and talin degradation were determined by Western blotting, using specific antibodies.

RESULTS

In the control and prednisolone (1.0 mg/kg) groups, serum AST and ALT levels were elevated, and cell membrane bleb formation was observed after 2 h of reperfusion. Moreover, calpain mu activation, talin degradation, and overexpression of IL-beta and TNF-alpha mRNAs were detected. Infusion of prednisolone at 3.0 or 10 mg/kg significantly suppressed biochemical and microscopic changes. At 10 mg/kg, prednisolone markedly suppressed IL-beta and TNF-alpha transcription and calpain mu activation and talin degradation, consistent with the improved 7-day survival after total hepatic ischemia (75% vs. 25% in control group, P = 0.039).

CONCLUSIONS

Cytoprotective effect of prednisolone in hepatic IR injury was closely associated with suppression of IL-beta/TNF-alpha production and calpain mu activation.

[A case of multiple sclerosis with recurrent episodes of psychiatric symptoms]

We reported a 19-year-old woman with multiple sclerosis (MS) with recurrent episodes of psychiatric symptoms at the age of 10 and 19, as the first and 11th relapse, respectively. Her first episode of MS resembled acute encephalitis at the age of 9 and she relapsed 12 times. The psychiatric symptoms were not mood disorders but altered states of consciousness, such as the delirous state. She was treated with high doses of intravenous methylpredonisolone and her symptoms were almost resolved, but her anxiety neurosis remained. Her MRI showed demyelination in the white matter of the frontal lobe and the hippocampus, which suggested that psychiatric symptoms of MS would be related to the frontal lobe lesion.

Automatic static threshold perimetry is useful for estimating the effects of laser photocoagulation on diabetic maculopathy

Focal photocoagulation was performed on 18 eyes in 18 diabetes patients; a visual acuity test, fluorescein angiography and automated static threshold perimetry by Octopus automated static perimetry (program 31) were conducted before and 1, 3 and 6 months after krypton laser photocoagulation. Central field sensitivity and total loss were measured by automated static threshold perimetry. Group A (13 eyes) had a total loss of less than 150 dB. In these subjects, mild fluorescein leakage was detected within the area of the vascular arcade. In group B (5 eyes) with a total loss of greater than 150 dB, diffuse fluorescein leakage was also detected outside the vascular arcade. The central field sensitivity was reduced in 2 eyes of group B. The total loss worsened in 8 eyes of group A (61.5%) and 5 eyes of group B (100%). Inspection of photographs gave the impression that the degree of fluorescein leakage and the area of the avascular zone on fluorescein angiography accorded with total loss, thus suggesting that total loss reflects visual functions better than visual acuity or central field sensitivity. Therefore, automated static threshold perimetry appears to be a useful method for estimating visual functions after photocoagulation in diabetic maculopathy patients.

[Importance of Helicobacter pylori in the pathogenesis of gastric cancer. Experimental models in rodents]

We found that the seroprevalence in Cancer Institute of H. pylori infection was significantly more frequent in gastric cancer than in age- and gender-matched controls. This study suggested an epidemiological link between H. pylori infection and gastric cancer. H. pylori exhibits a complex system of enzymes which serve a range of functions. Toxic effects are produced by urease (UR), phospholipase (PL) and alcohol dehydrogenase (ADH). We embarked on an exploration of the enzyme activities of H. pylori infected patients using a TLC-autoradioluminography. This method has a wide dynamic range and could offer an analytical technique for studying a radioactive compound and its enzymes in H. pylori infected mucosa. Biopsies samples taken from 21 gastric cancer patients and 95 controls were studied. Although high activity of UR indicates well the presence of H. pylori impairment, activities of ADH and PL reflects more the chronicity of mucosal damage in both groups. Clearly, the enzyme profile showed in our study reflects the "physiological" adaptations behind chronic injured mucosal changes but its relation to gastric cancer and H. pylori needs further study. There is an urgent need to understand the carcinogenesis process using animal models. We performed previous study for to explore the effect of H. pylori infection on N- methyl-N-nitrosourea-induced (MNU) gastric carcinogenesis in mice C57BL/6 mice were administered broth culture of H. pylori and given MNU in drinking water. In terms of the incidence of neoplasms development was increase in the MNU group pre-infected with H. pylori. That findings showed that C57BL/6 mice-infected model is well suited for investigating the bacteria promoter effect in the gastric carcinogenesis. Finally another rodent model study (still in process) showed rapid development of hyperplastic gastritis with gastric erosions in H. pylori-infected MTH1 knockout mice. We sought to further evaluate MTH1 knockout mice as potential test animal for carcinogenesis.

CONCLUSION

It is suggested that H. pylori infection is an important risk factor for the development of gastric cancer. The possibility that this organism acts etiologically, exerting its effect over long period of time, is biologically plausible. However, the role of H. pylori per se in that process is still a matter of discussion. The various enzymes of H. pylori discussed in this paper support colonization, and are perhaps important for epithelial damage, they could contribute to the stimulation and modulation of the chronic inflammatory response, but its relation to gastric cancer and H. pylori needs further study. Finally H. pylori in C57BL/6 and knockout mice showed excellent colonization at two months and six months after infection there was adenomatous, hyperplastic and ulcerative changes. Those findings showed that both mice-infected models are well suited for investigating the bacteria promoter effect in the gastric carcinogenesis.

A clinical study of surgical treatment of patients with carcinoma of the cervical esophagus extending to the thoracic esophagus

OBJECTIVE

We studied optimum surgery for carcinoma of the cervical esophagus extending to the thoracic esophagus (Ce-Ut carcinoma).

METHODS

Subjects were 13 patients diagnosed with Ce-Ut carcinoma treated at our institute from January 1989 to December 1998. Clinicopathologic information such as surgical procedures, pathologic findings, and postoperative complications were analyzed.

RESULTS

In 10, laryngoesophagectomy was conducted due to tracheal invasion by the tumor. In 7, mediastinal tracheostomy was done because of the extended resection of the proximal trachea. In 3, the larynx was preserved and, in 2, cricopharyngeal myotomy was added. Lymph node metastasis was found only in the neck and the upper mediastinum at surgery and recurrences were all lung metastasis. The incidence of postoperative complications was very high (76.9%), and 1 patient died due to widespread tracheal necrosis. The cumulative 5-year survival rate for the group was 33.3% and that for the 9 curative cases was 50%, but most of the cases who underwent noncurative resection and/or who received preoperative therapy for widespread invasion to surrounding organs died within a year.

CONCLUSION

The prognosis of patients who undergoing curative extended resection of the proximal trachea and suitable lymph node dissection in the neck and upper mediastinum may improve, and larynx-preserving surgery is recommended for patients without tracheal invasion. Despite preoperative chemoradiotherapy, the prognosis of patients with widespread invasion to surrounding organs was very poor, and clinical studies on new therapeutic strategies for these advanced cases are needed to improve the prognosis of Ce-Ut carcinoma patients.

Dobutamine stress echocardiography for the diagnosis of myocardial viability: assessment of left ventricular systolic velocities in longitudinal axis by pulsed Doppler tissue imaging

Dobutamine (DOB) stress two-dimensional echocardiography is an established method for the detection of viable myocardium, but conventional assessment of wall motion is subjective. We measured quantitatively the left ventricular systolic velocities along the longitudinal axis by pulsed Doppler tissue imaging (DTI). In 30 patients with previous myocardial infarction, pulsed DTI focused on the infarct area was performed from an apical two- or four-chamber view before and during DOB (10 microg/kg/min) stress one day before coronary angioplasty. We calculated peak systolic velocity (S), regional pre-ejection period (PEP, the time interval from the onset of QRS to the onset of systolic wave) and regional ejection time (ET). Left ventriculography was obtained before and 3 months after coronary angioplasty to assess regional wall motion. Improvement of abnormal wall motion was observed in 19 patients (group P) but not in 11 (group N). Group P had significantly larger S and smaller PEP/ET than group N during DOB stress, although there were no significant differences in these indices between the groups at baseline. As a consequence, group P had a significantly larger percent change in S and a smaller percent change in PEP/ET than group N (164+/-39 vs 117+/-20% and 88+/-17 vs 116+/-29%, respectively, p < 0.01). It is suggested that the quantitative measurement of longitudinal systolic velocities during DOB stress by DTI is useful for the precise assessment of myocardial viability.

Nitric oxide enhances expression and shedding of tumor necrosis factor receptor I (p55) in endothelial cells

The biological actions of tumor necrosis factor-alpha (TNF-alpha) are mediated by 2 distinct receptors, TNF-RI (p55) and TNF-RII (p75). The extracellular domains of both receptors are shed in soluble form (sTNF-RI and sTNF-RII). The soluble receptors are involved in regulating TNF-alpha activities and may have therapeutic potential as TNF-neutralizing agents. However, it remains unclear as to what kind of physiological molecule can regulate TNF receptors. Nitric oxide (NO) mediates a variety of biological and pathophysiological functions. We hypothesized that NO may modulate the expression and shedding of TNF-RI. An NO donor, diethylamine/NO complex (NOC 5), increased sTNF-RI in the supernatants of ECV304, a human umbilical vein cell line, in a dose-dependent manner. TNF-RI mRNA in these cells was upregulated by NOC 5. 8-Br-cGMP and peroxynitrate had no effect on sTNF-RI release. Genistein and herbimycin A, inhibitors of tyrosine kinase, inhibited sTNF-RI release. Herbimycin A inhibited the levels of TNF-RI mRNA enhanced by NOC 5, which downregulated the surface expression of TNF-RI, indicating that NO is also involved in the shedding process of TNF-RI. The shedding of TNF-RI was abolished by a synthetic inhibitor of matrix metalloproteinase, KB-R8301. In conclusion, NO enhanced the release of sTNF-RI from endothelial cells by a cGMP-independent mechanism. Dual pathways suggested for NO-induced sTNF-RI release include (1) enhanced expression of TNF-RI, at least partially, by a tyrosine kinase-dependent mechanism and (2) increased shedding of TNF-RI by a type of metalloproteinase.

[Accidental decrease in the air flow during air/oxygen sevoflurane anesthesia]

We describe our experience of an accidental decrease in the air flow during air/oxygen sevoflurane anesthesia. According to the malfunction of an air compressor system, dehydration of the compressed air was inadequate, and the wet air was delivered to the anesthesia machine. The moisture was formed at a flow control valve to cause a gradual decrease in the air flow. The low-pressure alarm did not work at that time, because the pressure of the air supply was normal. There are two types of medical air, one is produced from the ambient air by air compressor system and another is the synthetic air which is a mixture of oxygen and nitrogen. Although the synthetic air is always dry and clean, the former contains dust, bacteria, and moisture. There is a possibility that all of these particles cannot be excluded before use. Accordingly, we must check the air compressor system routinely when a source of the compressed air is used.

Apoptosis in rat cardiac myocytes induced by Fas ligand: priming for Fas-mediated apoptosis with doxorubicin

Fas/Fas ligand (FasL) is well known for its role in delivering apoptotic signals; however, it is unclear whether FasL can mediate apoptosis in cardiomyocytes. We hypothesized that apoptosis via Fas/FasL system may be augmented in damaged cardiomyocytes. To determine whether FasL mediates cardiomyocyte apoptosis, recombinant FasL (rFasL) was added to the culture of neonatal rat ventricular myocytes pretreated with and without doxorubicin. Without doxorubicin, high dose of rFasL caused an increase in TUNEL-positive cardiomyocytes and a mild decrease in MTT activities. When cardiomyocytes were pretreated with doxorubicin (0.5 microM), rFasL dramatically augmented TUNEL-positive cardiomyocytes in a concentration-dependent manner, which was accompanied with nuclear fragmentations. The rFasL also caused a concentration-dependent reduction in MTT activities in cardiomyocytes. The rFasL-induced caspase-8 activity was greatly facilitated by pretreatment of doxorubicin. TUNEL-positive nuclei with rFasL was inhibited by Fas-Fc, neutralizing agent of rFasL, and Z-IETD-FMK, caspase-8 inhibitor. Fas mRNA transcript by RT-PCR was up-regulated in cardiomyocytes with doxorubicin. We conclude that FasL can induce cardiomyocyte apoptosis particularly when cardiomyocyte becomes susceptible for Fas-mediated apoptosis.

Does central venous pressure reflect the circulating blood volume for the decrement of compliance just after esophagectomy?

This study investigates whether the pressure parameters obtained from the Swan-Ganz catheter (SGC) accurately reflect the circulating blood volume just after en bloc resection of the thoracic esophagus with regional lymph node dissection. It is well known that this operation induces severe hemodynamic changes and although the pressure parameters obtained from the SGC are an accepted means of monitoring circulating blood volume, we have often experienced a discrepancy between the SGC data and the clinical state. We examined the pressure parameters and diameter of the inferior vena cava (IVC) and left ventricle (LV), and the central venous compliance using SGC and echocardiography in ten patients who underwent esophagectomy for esophageal cancer. The central venous pressure, pulmonary arterial mean pressure, and pulmonary artery wedged pressure were significantly increased just after the operation compared with the preoperative levels, while the diameters of the IVC and LV decreased just after the operation. The compliances of the IVC decreased significantly just after the operation. The hemodynamic shift to the third space after esophagectomy induces decrement of the compliances of IVC. As the CVP does not always reflect the circulating blood volume, measuring the diameter of the IVC using echocardiography is extremely useful for monitoring circulating blood volume just after esophagectomy.

Anti-inflammatory cytokine profile in human heart failure: behavior of interleukin-10 in association with tumor necrosis factor-alpha

Proinflammatory cytokines, i.e., tumor necrosis factor-alpha (TNFalpha), participate in the development and the progression of congestive heart failure (CHF). On the other hand, an anti-inflammatory cytokine may neutralize the proinflammatory cytokines of CHF. Interleukin-10 (IL-10) is known to suppress the synthesis of proinflammatory cytokines. IL-10 and the IL-10 receptor system was investigated in comparison with the behavior of TNFalpha in 68 patients with various causes of CHF (mean age: 61 years) and in 31 normal subjects (61 years). The circulating IL-10 level was higher in CHF patients than in normal subjects (p<0.05). The TNFalpha level was higher in CHF patients than in control subjects (p<0.005). The ratio of IL-10 to TNFalpha tended to be higher in control subjects than in patients with CHF (p = 0.09). With lipopolysaccharide treatment, the release of IL-10 was more enhanced from mononuclear leukocyte of patients with CHF than from control subjects (p<0.05). The expression of the IL-10 receptor estimated by flow cytometry of mononuclear leukocytes was higher in the CHF patients than in the normal subjects. The IL-10/IL-10 receptor system was activated, at least partly, to downregulate an excess of TNFalpha in patients with advanced CHF. IL-10 may be an important inherent component of the cytokine network of CHF.

Effect of some heavy metal ions on copper-induced metallothionein synthesis in the yeast Saccharomyces cerevisiae

Copper-induced metallothionein (MT) synthesis in Saccharomyces cerevisiae was investigated in order to associate this exclusively with Cu2+ in vivo, when cultured in nutrient medium containing other heavy metal ions. Expression of the CUP1 promoter/lacZ fusion gene was inhibited by all heavy metal ions tested, especially Cd2+ and Mn2+. By adding Cd2+ and Mn2+ at 10 microM concentration, the beta-galactosidase activity decreased by about 80% and 50% of the maximum induction observed with 1 mM CuSO4, respectively. Furthermore, cell growth was markedly inhibited by combinations of 1 mM-Cu2+ and 1 microM-Cd2+. Therefore, the yeast S. cerevisiae could not rely on MT synthesis as one of the copper-resistance mechanisms, when grown in a Cd2+ environment. In contrast, the presence of Mn2+ in the nutrient medium showed alleviation rather than growth inhibition by high concentrations of Cu2+. The recovery from growth inhibition by Mn2+ was due to decreased Cu2+ accumulation. Inhibitory concentrations of Co2+, Ni2+ and Zn2+ on expression of the CUP1p/lacZ fusion gene were at least one order of magnitude higher than that of Cd2+ and Mn2+. These results are discussed in relation to Cu2+ transport and Cu-induced MT synthesis in the copper-resistance mechanism of the yeast S. cerevisiae.