Peripheral Immune Activation in Mice Elicits Unfolded Protein Responses Independent on MyD88 Pathway in the Liver but not the Hypothalamus and Hippocampus

Neuroimmune interactions between the immune system and CNS as well as peripheral organs such as the liver play a key role in the pathophysiological state of diseases. Unfolded protein responses (UPRs), which are activated by cells in response to endoplasmic reticulum stress, have been linked to the occurrence of inflammation diseases, neurodegenerative diseases, and metabolic disorders such as type 2 diabetes. Peripheral injection of lipopolysaccharide (LPS) is known to induce a systemic inflammatory response, along with fever, anorexia, and depressive behaviors. LPS also elicits UPRs, although the underlying physiological mechanism remains unclear. In the present study, we investigated whether peripheral activation of the immune system can elicit UPRs in the CNS and liver. Peripheral injection of LPS is known to elevate pro-inflammatory cytokines in the liver, hypothalamus and hippocampus. We report that LPS-induced systemic inflammation elicits UPRs in the liver, but not the hypothalamus. Injection of LPS upregulated the expression levels of glucose-regulated protein 78 and pro-apoptotic transcription factor C/EBP homologous protein, along with increased splicing of X-box binding protein one mRNA in the liver, but not in the hypothalamus and hippocampus. Myeloid differentiation primary response 88 (MyD88), an adaptor protein, is known to play a key role in the signal transduction of LPS mediated by Toll-like receptor 4. Using MyD88 deficient mice, we found that LPS-induced UPRs occurred independently of MyD88 expression. In summary, peripheral activation of the immune system elicits UPRs in the liver, but not the hypothalamus and hippocampus, which may have implications for the pathophysiology of diseases.

Spike firing attenuation of serotonin neurons in learned helplessness rats is reversed by ketamine

Animals suffering from uncontrollable stress sometimes show low effort to escape stress (learned helplessness). Changes in serotonin (5-hydroxytryptamine) signalling are thought to underlie this behaviour. Although the release of 5-hydroxytryptamine is triggered by the action potential firing of dorsal raphe nuclei 5-hydroxytryptamine neurons, the electrophysiological changes induced by uncontrollable stress are largely unclear. Herein, we examined electrophysiological differences among 5-hydroxytryptamine neurons in naïve rats, learned helplessness rats and rats resistant to inescapable stress (non-learned helplessness). Five-week-old male Sprague Dawley rats were exposed to inescapable foot shocks. After an avoidance test session, rats were classified as learned helplessness or non-learned helplessness. Activity-dependent 5-hydroxytryptamine release induced by the administration of high-potassium solution was slower in free-moving learned helplessness rats. Subthreshold electrophysiological properties of 5-hydroxytryptamine neurons were identical among the three rat groups, but the depolarization-induced spike firing was significantly attenuated in learned helplessness rats. To clarify the underlying mechanisms, potassium (K+) channels regulating the spike firing were initially examined using naïve rats. K+ channels sensitive to 500 μM tetraethylammonium caused rapid repolarization of the action potential and the small conductance calcium-activated K+ channels produced afterhyperpolarization. Additionally, dendrotoxin-I, a blocker of Kv1.1 (encoded by Kcna1), Kv1.2 (encoded by Kcna2) and Kv1.6 (encoded by Kcna6) voltage-dependent K+ channels, weakly enhanced the spike firing frequency during depolarizing current injections without changes in individual spike waveforms in naïve rats. We found that dendrotoxin-I significantly enhanced the spike firing of 5-hydroxytryptamine neurons in learned helplessness rats. Consequently, the difference in spike firing among the three rat groups was abolished in the presence of dendrotoxin-I. These results suggest that the upregulation of dendrotoxin-I-sensitive Kv1 channels underlies the firing attenuation of 5-hydroxytryptamine neurons in learned helplessness rats. We also found that the antidepressant ketamine facilitated the spike firing of 5-hydroxytryptamine neurons and abolished the firing difference between learned helplessness and non-learned helplessness by suppressing dendrotoxin-I-sensitive Kv1 channels. The dendrotoxin-I-sensitive Kv1 channel may be a potential target for developing drugs to control activity of 5-hydroxytryptamine neurons.

Expression of PRIP, a phosphatidylinositol 4,5-bisphosphate binding protein, attenuates PI3K/AKT signaling and suppresses tumor growth in a xenograft mouse model

Cancer is characterized by uncontrolled proliferation resulting from aberrant cell cycle progression. The activation of phosphatidylinositol 3-kinase (PI3K)/AKT signaling, a regulatory pathway for the cell cycle, stabilizes cyclin D1 in the G1 phase by inhibiting the activity of glycogen synthase kinase 3β (GSK3β) via phosphorylation. We previously reported that phospholipase C-related catalytically inactive protein (PRIP), a phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] binding protein, regulates PI3K/AKT signaling by competitively inhibiting substrate recognition by PI3K. Therefore, in this study, we investigated whether PRIP is involved in cell cycle progression. PRIP silencing in MCF-7 cells, a human breast cancer cell line, demonstrated PI(3,4,5)P3 signals accumulated at the cell periphery compared to that of the control. This suggests that PRIP reduction enhances PI(3,4,5)P3-mediated signaling. Consistently, PRIP silencing in MCF-7 cells exhibited increased phosphorylation of AKT and GSK3β which resulted in cyclin D1 accumulation. In contrast, the exogenous expression of PRIP in MCF-7 cells evidenced stronger downregulation of AKT and GSK3β phosphorylation, reduced accumulation of cyclin D1, and diminished cell proliferation in comparison to control cells. Flow cytometry analysis indicated that MCF-7 cells stably expressing PRIP attenuate cell cycle progression. Importantly, tumor growth of MCF-7 cells stably expressing PRIP was considerably prevented in an in vivo xenograft mouse model. In conclusion, PRIP expression downregulates PI3K/AKT/GSK3β-mediated cell cycle progression and suppresses tumor growth. Therefore, we propose that PRIP is a new therapeutic target for anticancer therapy.

Possible Involvement of MyD88 in Regulating Stress Response in Mice

Myeloid differentiation primary response 88 (MyD88) is an adapter protein of the toll-like receptor (TLR) family that regulates innate immune function. Here, we identified a novel role of MyD88 in regulating stress response. MyD88 deficiency decreased immobility time in the forced swim test without affecting locomotor activity in mice. Immobilization stress-induced production of serum corticosterone was also completely inhibited by MyD88 deficiency. Stress induced decrease in glucocorticoid receptor in the hippocampus. On the other hand, stress exposure in MyD88 deficient mice did not cause decrease in its level in the hippocampus. Furthermore, immobilization stress-induced reduction of brain-derived neurotrophic factor (BDNF) levels in the hippocampus was ameliorated by MyD88 deficiency. These results suggest that MyD88 deficiency attenuates depression-like behavior by regulating corticosterone and BDNF levels. Overall, these results indicate the key role of MyD88 in regulating stress response in mice.

IL-6 Induced by Periodontal Inflammation Causes Neuroinflammation and Disrupts the Blood-Brain Barrier

Background: Periodontal disease (PD) is a risk factor for systemic diseases, including neurodegenerative diseases. The role of the local and systemic inflammation induced by PD in neuroinflammation currently remains unclear. The present study investigated the involvement of periodontal inflammation in neuroinflammation and blood–brain barrier (BBB) disruption. Methods: To induce PD in mice (c57/BL6), a ligature was placed around the second maxillary molar. Periodontal, systemic, and neuroinflammation were assessed based on the inflammatory cytokine mRNA or protein levels using qPCR and ELISA. The BBB permeability was evaluated by the mRNA levels and protein levels of tight junction-related proteins in the hippocampus using qPCR and immunofluorescence. Dextran tracing in the hippocampus was also conducted to examine the role of periodontal inflammation in BBB disruption. Results: The TNF-α, IL-1β, and IL-6 levels markedly increased in gingival tissue 1 week after ligation. The IL-6 serum levels were also increased by ligature-induced PD. In the hippocampus, the IL-1β mRNA expression levels were significantly increased by ligature-induced PD through serum IL-6. The ligature-induced PD decreased the claudin 5 expression levels in the hippocampus, and the neutralization of IL-6 restored its levels. The extravascular 3-kDa dextran levels were increased by ligature-induced PD. Conclusions: These results suggest that the periodontal inflammation-induced expression of IL-6 is related to neuroinflammation and BBB disruption in the hippocampus, ultimately leading to cognitive impairment. Periodontal therapy may protect against neurodegenerative diseases.

Importance of the Habenula for Avoidance Learning Including Contextual Cues in the Human Brain: A Preliminary fMRI Study

Human habenula studies are gradually advancing, primarily through the use of functional magnetic resonance imaging (fMRI) analysis of passive (Pavlovian) conditioning tasks as well as probabilistic reinforcement learning tasks. However, no studies have particularly targeted aversive prediction errors, despite the essential importance for the habenula in the field. Complicated learned strategies including contextual contents are involved in making aversive prediction errors during the learning process. Therefore, we examined habenula activation during a contextual learning task. We performed fMRI on a group of 19 healthy controls. We assessed the manually traced habenula during negative outcomes during the contextual learning task. The Beck Depression Inventory-Second Edition (BDI-II), the State-Trait-Anxiety Inventory (STAI), and the Temperament and Character Inventory (TCI) were also administered. The left and right habenula were activated during aversive outcomes and the activation was associated with aversive prediction errors. There was also a positive correlation between TCI reward dependence scores and habenula activation. Furthermore, dynamic causal modeling (DCM) analyses demonstrated the left and right habenula to the left and right hippocampus connections during the presentation of contextual stimuli. These findings serve to highlight the neural mechanisms that may be relevant to understanding the broader relationship between the habenula and learning processes.

Anti-inflammatory effects of miRNA-146a induced in adipose and periodontal tissues

MicroRNA (miRNA) plays an important role in diverse cellular biological processes such as inflammatory response, differentiation and proliferation, and carcinogenesis. miR-146a has been suggested as a negative regulator of the inflammatory reaction. Although, it has been reported as expressed in inflamed adipose and periodontal tissues, however, miR-146a's inhibitory effects against inflammatory response in both the tissues, are not well understood. Therefore, in this study, the inhibitory effects of miR-146a on both adipose and periodontal inflammation, was investigated. In vitro study has revealed that miR-146a transfection into either adipocytes or gingival fibroblasts, has resulted in a reduced cytokine gene expression, observed on co-culturing the cells with macrophages in the presence of lipopolysaccharides (LPS), in comparison to the control miRNA transfected. Similarly, miR-146a transfection into macrophages resulted in a reduced expression of TNF-α gene and protein in response to LPS stimulation. In vivo study revealed that a continuous intravenous miR-146a administration into mice via tail vein, protected the mice from developing high-fat diet-induced obesity and the inflammatory cytokine gene expression was down-regulated in both adipose and periodontal tissues. miR-146a appeared to be induced by macrophage-derived inflammatory signals such as TNF-α by negative feed-back mechanism, and it suppressed inflammatory reaction in both adipose and periodontal tissues. Therefore, miR-146a could be suggested as a potential therapeutic molecule and as a common inflammatory regulator for both obesity-induced diabetes and related periodontal diseases.

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miR-146a induced by adipose and periodontal inflammation via macrophage mediators.

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miR-146a is a negative inflammation regulator in adipose and periodontal tissues.

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miR-146a is a potential therapeutic target against obesity and periodontal diseases.

Phospholipase C-related catalytically inactive protein regulates lipopolysaccharide-induced hypothalamic inflammation-mediated anorexia in mice

Peripheral lipopolysaccharide (LPS) injection induces systemic inflammation through the activation of the inhibitor of nuclear factor kappa B (NF-κB) kinase (IKK)/NF-κB signaling pathway, which promotes brain dysfunction resulting in conditions including anorexia. LPS-mediated reduction of food intake is associated with activation of NF-κB signaling and phosphorylation of the transcription factor signal transducer and activator of transcription 3 (STAT3) in the hypothalamus. We recently reported phospholipase C-related catalytically inactive protein (PRIP) as a new negative regulator of phosphatidylinositol 3-kinase/AKT signaling. AKT regulates the IKK/NF-κB signaling pathway; therefore, this study aimed to investigate the role of PRIP/AKT signaling in LPS-mediated neuroinflammation-induced anorexia. PRIP gene (Prip1 and Prip2) knockout (Prip-KO) mice intraperitoneally (ip) administered with LPS exhibited increased anorexia responses compared with wild-type (WT) controls. Although few differences were observed between WT and Prip-KO mice in LPS-elicited plasma pro-inflammatory cytokine elevation, hypothalamic pro-inflammatory cytokines were significantly upregulated in Prip-KO rather than WT mice. Hypothalamic AKT and IKK phosphorylation and IκB degradation were significantly increased in Prip-KO rather than WT mice, indicating further promotion of AKT-mediated NF-κB signaling. Consistently, hypothalamic STAT3 was further phosphorylated in Prip-KO rather than WT mice. Furthermore, suppressor of cytokine signaling 3 (Socs3), a negative feedback regulator for STAT3 signaling, and cyclooxogenase-2 (Cox2), a candidate molecule in LPS-induced anorexigenic responses, were upregulated in the hypothalamus in Prip-KO rather than WT mice. Pro-inflammatory cytokines were upregulated in hypothalamic microglia isolated from Prip-KO rather than WT mice. Together, these findings indicate that PRIP negatively regulates LPS-induced anorexia caused by pro-inflammatory cytokine expression in the hypothalamus, which is mediated by AKT-activated NF-κB signaling. Importantly, hypothalamic microglia participate in this PRIP-mediated process. Elucidation of PRIP-mediated neuroinflammatory responses may provide novel insights into the pathophysiology of many brain dysfunctions.

Phospholipase C-related catalytically inactive protein regulates cytokinesis by protecting phosphatidylinositol 4,5-bisphosphate from metabolism in the cleavage furrow

Cytokinesis is initiated by the formation and ingression of the cleavage furrow. Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P₂] accumulation followed by RhoA translocation to the cleavage furrow are prerequisites for cytokinesis progression. Here, we investigated whether phospholipase C (PLC)-related catalytically inactive protein (PRIP), a metabolic modulator of PI(4,5)P₂, regulates PI(4,5)P₂-mediated cytokinesis. We found that PRIP localised to the cleavage furrow during cytokinesis. Moreover, HeLa cells with silenced PRIP displayed abnormal cytokinesis. Importantly, PI(4,5)P₂ accumulation at the cleavage furrow, as well as the localisation of RhoA and phospho-myosin II regulatory light chain to the cleavage furrow, were reduced in PRIP-silenced cells. The overexpression of oculocerebrorenal syndrome of Lowe-1 (OCRL1), a phosphatidylinositol-5-phosphatase, in cells decreased PI(4,5)P₂ levels during early cytokinesis and resulted in cytokinesis abnormalities. However, these abnormal cytokinesis phenotypes were ameliorated by the co-expression of PRIP but not by co-expression of a PI(4,5)P₂-unbound PRIP mutant. Collectively, our results indicate that PRIP is a component at the cleavage furrow that maintains PI(4,5)P₂ metabolism and regulates RhoA-dependent progression of cytokinesis. Thus, we propose that PRIP regulates phosphoinositide metabolism correctively and mediates normal cytokinesis progression.

Immobilization stress induces XBP1 splicing in the mouse brain

Cells activate the unfolded protein response (UPR) to cope with endoplasmic reticulum (ER) stress. In the present study, we investigated the possible involvement of psychological stress on UPR induction in the mouse brain. When mice were exposed to immobilization stress for 8 h, XBP1 mRNA splicing was significantly induced in the hippocampus, cortex, hypothalamus, cerebellum, and brain stem. On the other hand, we did not observe any increase in XBP1 splicing in the liver, suggesting that this effect is specific to the brain. Stress-induced XBP1 splicing was attenuated 2 days after immobilization stress. We did not observe increases in any other UPR genes, such as CHOP or GRP78, in mouse brains after immobilization stress. These findings indicate an important specific role of XBP1 in response to psychological stress in the mouse brain.

[The Role of the Habenula in Depression: A Review of the Human fMRI Studies]

Depression has various symptoms, such as depressed mood or loss of motivation, and the pathophysiological mechanisms remain unclear. Recent studies have increased the understanding of the role of the habenula, since the habenula is reported to control the metabolism of monoamine neurotransmitters in the brain through direct projections to the ventral tegmental area and raphe nucleus. Human neuroimaging studies have been performed to attempt to clarify the mechanisms of depression. This manuscript mainly introduces human neuroimaging studies of the role of the habenula in depression.

Data on the effect of maternal separation coupled with social isolation in a forced swim test and gene expression of glial fibrillary acid protein in the prefrontal cortex of rats

Early life adversity, such as neglect, increases the risk for major depressive disorder and anxiety disorders. It is well-known that astrocytes have key roles in brain function. In this paper, we show the effect of maternal separation (MS) coupled with social isolation on stress response and gene expression of glial fibrillary acidic protein (GFAP) as a marker of astrocytes, in early life and adulthood. Stress response was evaluated by using a forced swim test. GFAP gene expression level was evaluated by using the quantitative polymerase chain reaction (qPCR) method. The data in this article provide indexes affected by early life stress.

Sodium butyrate abolishes lipopolysaccharide-induced depression-like behaviors and hippocampal microglial activation in mice

Patients with major depressive disorder have elevated peripheral inflammation; the degree of this increase correlates with the severity of the disorder. Chronic psychological stress increases pro-inflammatory cytokines and promotes microglial activation, leading to stress vulnerability. Epigenetics, including DNA methylation and histone modification, are also related to the pathophysiology of major depressive disorder. Sodium butyrate (SB), a histone deacetylase inhibitor, exerts an antidepressant effect by altering gene expression in the hippocampus. In this study, we investigated whether lipopolysaccharide (LPS)-induced depressive-like behaviors in mice are affected by the repeated treatment with SB. Intraperitoneal injection of LPS (5 mg/kg) induced cytokines and ionized calcium-binding adaptor molecule 1(Iba1), a marker of microglial activation, in the hippocampus. It also increased the immobility time in a forced swim test, without changing locomotion. Repeated treatment with SB reduced LPS-induced alterations. These findings suggested that epigenetic regulation exist in hippocampal microglial activation, and is involved in depressive-like behaviors associated with neuro-inflammation. Further, using cDNA microarray analyses, we examined whether LPS and SB treatment affected the microglial gene profiles. Our results indicated 64 overlapping genes, between LPS-increased genes and SB-decreased genes. Among these genes, EF hand calcium binding domain 1 was a particularly distinct candidate gene. Altogether, our findings indicated that microglial activation mediated through epigenetic regulation may be involved in depressive-like behaviors. In addition, we demonstrated the effect of SB on gene information in hippocampal microglia under neuroinflammatory conditions.

Phospholipase C-related catalytically inactive protein can regulate obesity, a state of peripheral inflammation

Obesity is defined as abnormal or excessive fat accumulation. Chronic inflammation in fat influences the development of obesity-related diseases. Many reports state that obesity increases the risk of morbidity in many diseases, including hypertension, dyslipidemia, type 2 diabetes, coronary heart disease, stroke, sleep apnea, and breast, prostate and colon cancers, leading to increased mortality. Obesity is also associated with chronic neuropathologic conditions such as depression and Alzheimer's disease. However, there is strong evidence that weight loss reduces these risks, by limiting blood pressure and improving levels of serum triglycerides, total cholesterol, low-density lipoprotein (LDL)-cholesterol, and high-density lipoprotein (HDL)-cholesterol. Prevention and control of obesity is complex, and requires a multifaceted approach. The elucidation of molecular mechanisms driving fat metabolism (adipogenesis and lipolysis) aims at developing clinical treatments to control obesity. We recently reported a new regulatory mechanism in fat metabolism: a protein phosphatase binding protein, phospholipase C-related catalytically inactive protein (PRIP), regulates lipolysis in white adipocytes and heat production in brown adipocytes via phosphoregulation. Deficiency of PRIP in mice led to reduced fat accumulation and increased energy expenditure, resulting in a lean phenotype. Here, we evaluate PRIP as a new therapeutic target for the control of obesity.

The potential use of histone deacetylase inhibitors in the treatment of depression

Numerous preclinical studies demonstrate that changes in gene expression in the brain occur in animal models of depression using exposure to stress, such as social defeat and leaned helplessness, and that repeated administration of antidepressants ameliorates these stress-induced changes in gene expression. These findings suggest that alteration in gene transcription in the central nervous system in response to stress plays an important role in the pathophysiology of depression. Recent advances in epigenetics have led to the realization that chromatin remodeling mediated by histone deacetylase (HDAC) is closely involved in the regulation of gene transcription. In this context, we first review several preclinical studies demonstrating the antidepressant-like efficacy of HDAC inhibitors. We then suggest the efficacy of HDAC inhibitors in treatment-resistant depression based on the mechanism of action of HDAC. Finally, we discuss the possibility of using HDAC inhibitors in patients with treatment-resistant depression.

Phospholipase C-related Catalytically Inactive Protein Is a New Modulator of Thermogenesis Promoted by β-Adrenergic Receptors in Brown Adipocytes

Phospholipase C-related catalytically inactive protein (PRIP) was first identified as an inositol 1,4,5-trisphosphate-binding protein, and was later found to be involved in a variety of cellular events, particularly those related to protein phosphatases. We previously reported that Prip knock-out (KO) mice exhibit a lean phenotype with a small amount of white adipose tissue. In the present study, we examined whether PRIP is involved in energy metabolism, which could explain the lean phenotype, using high-fat diet (HFD)-fed mice. Prip-KO mice showed resistance to HFD-induced obesity, resulting in protection from glucose metabolism dysfunction and insulin resistance. Energy expenditure and body temperature at night were significantly higher in Prip-KO mice than in wild-type mice. Gene and protein expression of uncoupling protein 1 (UCP1), a thermogenic protein, was up-regulated in Prip-KO brown adipocytes in thermoneutral or cold environments. These phenotypes were caused by the promotion of lipolysis in Prip-KO brown adipocytes, which is triggered by up-regulation of phosphorylation of the lipolysis-related proteins hormone-sensitive lipase and perilipin, followed by activation of UCP1 and/or up-regulation of thermogenesis-related genes (e.g. peroxisome proliferator-activated receptor-γ coactivator-1α). The results indicate that PRIP negatively regulates UCP1-mediated thermogenesis in brown adipocytes.

Possible involvement of rumination in gray matter abnormalities in persistent symptoms of major depression: an exploratory magnetic resonance imaging voxel-based morphometry study

BACKGROUND

A recent meta-analysis of many magnetic resonance imaging (MRI) studies has identified brain regions with gray matter (GM) abnormalities in patients with major depressive disorder (MDD). A few studies addressing GM abnormalities in patients with treatment-resistant depression (TRD) have yielded inconsistent results. Moreover, although TRD patients tend to exhibit ruminative thoughts, it remains unclear whether rumination is related to GM abnormalities in such patients or not.

METHODS

We conducted structural MRI scans and voxel-based morphometry (VBM) to identify GM differences among 29 TRD patients and 29 healthy age-matched and sex-matched controls. A response style questionnaire was used to assess the respective degrees of rumination in TRD patients. Structural correlates of rumination were examined.

RESULTS

TRD patients showed several regions with smaller GM volume than in healthy subjects: the left dorsal anterior cingulate cortex (ACC), right ventral ACC, right superior frontal gyrus, right cerebellum (Crus I), and cerebellar vermis. GM volumes in these regions did not correlate to rumination. However, whole-brain analysis revealed that rumination was positively correlated with the GM volume in the right superior temporal gyrus in TRD patients.

LIMITATIONS

Structural correlates of rumination were examined only in TRD patients.

CONCLUSIONS

Our data provide additional evidence supporting the hypothesis that TRD patients show GM abnormalities compared with healthy subjects. Furthermore, this report is the first to describe a study identifying brain regions for which the GM volume is correlated with rumination in TRD patients. These results improve our understanding of the anatomical characteristics of TRD.

Coulometric determination of dissolved hydrogen with a multielectrolytic modified carbon felt electrode-based sensor

A multielectrolytic modified carbon electrode (MEMCE) was fabricated by the electrolytic-oxidation/reduction processes. First, the functional groups containing nitrogen atoms such as amino group were introduced by the electrode oxidation of carbon felt electrode in an ammonium carbamate aqueous solution, and next, this electrode was electroreduced in sulfuric acid. The redox waves between hydrogen ion and hydrogen molecule at highly positive potential range appeared in the cyclic voltammogram obtained by MEMCE. A coulometric cell using MEMCE with a catalytic activity of electrooxidation of hydrogen molecule was constructed and was used for the measurement of dissolved hydrogen. The typical current vs. time curve was obtained by the repetitive measurement of the dissolved hydrogen. These curves indicated that the measurement of dissolved hydrogen was finished completely in a very short time (ca. 10 sec). A linear relationship was obtained between the electrical charge needed for the electrooxidation process of hydrogen molecule and dissolved hydrogen concentration. This indicates that the developed coulometric method can be used for the determination of the dissolved hydrogen concentration.

PMA-induced dissociation of Ku86 from the promoter causes transcriptional up-regulation of histamine H(1) receptor

Histamine H₁ receptor (H1R) gene is up-regulated in patients with allergic rhinitis, and its expression level strongly correlates with the severity of symptoms. However, the mechanism underlying this remains unknown. Here we report the mechanism of H1R gene up-regulation. The luciferase assay revealed the existence of two promoter regions, A and B1. Two AP-1 and one Ets-1 bound to region A, while Ku86, Ku70, and PARP-1 bound to region B1. Ku86 was responsible for DNA binding and poly(ADP-ribosyl)ated in response to phorbol-12-myristate-13-acetate stimulation, inducing its dissociation from region B1 that is crucial for promoter activity. Knockdown of Ku86 gene enhanced up-regulation of H1R gene expression. Experiments using inhibitors for MEK and PARP-1 indicate that regions A and B1 are downstream regulatory elements of the PKCδ/ERK/PARP-1 signaling pathway. Data suggest a novel mechanism for the up-regulation of H1R gene expression.

Antidepressant-like effect of sodium butyrate (HDAC inhibitor) and its molecular mechanism of action in the rat hippocampus

OBJECTIVES

Epigenetic mechanisms, such as changes in gene expression resulting from chromatin remodeling through histone acetylation, have been implicated in the pathophysiology of depression. However, the antidepressant-like effect of the histone deacetylase inhibitor sodium butyrate (SB) has been inconclusive. The aim of this study was to examine the antidepressant-like effect of SB and elucidate its molecular mechanisms.

METHODS

We examined the antidepressant-like effect of SB in a forced swim test (FST) and a tail suspension test (TST). Hippocampal gene expression analyses using DNA microarray and real-time PCR were undertaken. Western blotting and ChIP assay were undertaken to examine whether histone acetylation was associated with changes in gene expression by SB.

RESULTS

Repeated administration of SB significantly reduced immobility on the FST and the TST, and significantly altered the levels of mRNA for several genes; e.g., upregulation of transthyretin (Ttr) and downregulation of serotonin 2A receptor (Htr2a). Western blotting and ChIP assay revealed selective increases in histone H4 acetylation at the promoter of the Ttr gene with a significant increase in Ttr immunoreactivity 24 h after the final administration of SB.

CONCLUSION

These findings suggest the possibility that alterations in gene expression, including upregulation of Ttr and downregulation of several other genes, including Htr2a, may be involved in antidepressant-like effect of SB.

[Epigenetic mechanism of depression]

Numerous epigenetic studies have revealed that the acetylated status of histone as well as methylated status of cytosine is closely involved in gene transcription. Preclinical and clinical studies demonstrate that changes in levels of various genes in the brain including BDNF, play a role in the pathophysiology of depression. It is well known that the levels of BDNF mRNA and protein in the rat brain, such as frontal cortex and hippocampus, was decreased in response to stress, but the precise mechanism of stress-induced downregulation of BDNF has yet to be characterized. In this context, we examined the influence of a single immobilization stress (SIS) on the levels of total BDNF mRNA with each exon mRNA by real-time PCR and acetylated histone at the promoters of the BDNF gene by chromatin immunoprecipitaion assay in the rat hippocampus. SIS significantly decreased the levels of total BDNF mRNA with significant reduced levels of exon I and IV mRNA. Significant decreases in acetylated histone H3, but not H4, were found at the promoters of exons I, IV, and VI. On the other hand, antidepressant-like effects has been reported with sodium butylate (SB), a histone deacetylase (HDAC) inhibitor, promoting gene transcription. We also found antidepressant-like effect of repeated administration of SB in the forced swim test using rats. In addition, we found that upregulation in transthyretin mRNA in the rat hippocampus is, at least in part, associated with this effect using DNA microarray and real-time PCR. Based on these findings, it is postulated that epigenetic regulation of the BDNF gene by stress and antidepressants may be involved in the pathophysiology of depression.

MyD88 plays a key role in LPS-induced Stat3 activation in the hypothalamus

Infection causes the production of proinflammatory cytokines, which act on the central nervous system (CNS) and can result in fever, sleep disorders, depression-like behavior, and even anorexia, although precisely how cytokines regulate the functions of the CNS remain unclear. In the present study, we investigated the regulatory-molecular mechanisms by which cytokines affect hypothalamic function in a state of infection. The intraperitoneal administration of lipopolysaccharide (LPS), a ligand of Toll-like receptor 4 (TLR4), time-dependently (2-24 h) increased signal transducer and activator of transcription 3 (STAT3) phosphorylation in the hypothalamus and liver, which corresponded with anorexia observed within 24 h. Interestingly, the pattern of phosphorylation in response to LPS differed between the hypothalamus and liver. In the hypothalamus, LPS increased STAT3 phosphorylation from 2 h, with a peak at 4 h and a decline thereafter, whereas, in the liver, the peak activation of STAT3 persisted from 2 to 8 h. The time course of the LPS-induced expression of suppressor of cytokine signaling 3 (SOCS3), a STAT3-induced negative regulator of the Janus kinase-STAT pathway, was similar to that of STAT3 phosphorylation. Using mice deficient in myeloid differentiation primary-response protein 88 (MyD88), an adapter protein of TLR4, we found that LPS-induced STAT3 phosphorylation and SOCS3 expression in the hypothalamus and liver were predominantly mediated through MyD88. Moreover, we observed that MyD88-deficient mice were resistant to LPS-induced anorexia. Taken together, our findings reveal a novel mechanism, i.e., MyD88 plays a key role in mediating STAT3 phosphorylation and anorexia in the CNS in a state of infection and inflammation.

[Development of factor VIII inhibitor in three non-hemophiliac patients]

Infrequently, inhibitors against factor VIII can develop in non-hemophiliac patients and cause serious bleeding. In the last year, we have experienced 3 non-hemophiliac patients who developed factor VIII inhibitors. Here, we describe the clinical courses of the three patients and the characteristics of the inhibitors. Case 1: A 69-year-old man underwent a partial gastrectomy because of early gastric cancer, and one month later developed signs of a bleeding tendency such as hematemesis, tarry stools and intramuscular hemorrhage. Blood coagulation tests revealed prolongation of the activated partial thromboplastin time (aPTT), which had been normal on admission. Case 2: A 78-year-old woman with no previous disease history developed generalized subcutaneous purpura. Blood coagulation tests performed on admission revealed a prolonged aPTT. Case 3: A 30-year-old man was admitted to an emergency hospital because of left intrapleural hemorrhage and liver injury caused by a traffic accident. Two months later, a hematoma developed at the site of drainage in the left chest, and blood coagulation tests revealed prolongation of the aPTT, which had been normal on admission. Plasma factor VIII procoagulant activities in cases 1, 2 and 3 were 3%, 1% and 5%, respectively. The respective factor VIII inhibitor titers were 78, 870 and 0.5 Bethesda units/ml. The immunoglobulin class and subclass of the inhibitors examined by an ELISA method were: case 1, IgG1 and 4; case 2, IgG2 and 4 (dominant); case 3, IgG4. In cases 1 and 3, the patients recovered after glucocorticoid therapy, but in case 2 the patient died of intraperitoneal hemorrhage despite receiving two courses of methylprednisolone pulse therapy. The above clinical experience suggests that patients, who develop high titers of inhibitors may be refractory to ordinary immunosuppressive therapy, and therefore more aggressive therapy such as plasma exchange and/or bypass therapy using activated prothrombin complex concentrates or an activated factor VII preparation should be considered.

Saccadic tracking of a light grey target in the mantis, Tenodera aridifolia

I presented a horizontally moving square on a computer display to the mantis, Tenodera aridifolia, and examined the effects of target brightness and velocity, and background brightness on its tracking behavior. The mantis tracked a light grey square with more saccadic head movements than a black square, although these squares moved on a homogeneous background. The amplitude of saccades was larger when the light grey square moved at a lower velocity. The background brightness had little effect on the type (smooth or saccadic) of tracking behavior. These results suggest that the saccadic tracking of light grey objects on a homogeneous background may not be caused by low contrast, i.e., the difficulty in discriminating the object from the background. The possible biological significance of saccadic tracking on a homogenous background is discussed.

Serovar, pathogenicity and antimicrobial susceptibility of erysipelothrix rhusiopathiae isolates from farmed wild boars (Sus scrofa) affected with septicemic erysipelas in Japan

Six strains of Erysipelothrix rhusiopathiae were isolated from farmed wild boars with acute septicemic erysipelas during the period from 1983 to 1998 in Japan. All isolates belonged to serovar 1a or 2 (predominant serovars in swine). The 50 per cent lethal dose values of those isolates ranged from 10(1.3)to 10(6.2)colony forming units in mice. In swine, all isolates were virulent, capable of inducing localized or generalized urticarial lesions after intradermal inoculation. All of the isolates were resistant to oxytetracycline and/or dihydrostreptomycin. These observations suggest that E. rhusiopathiae strains isolated from wild boars may have aetiological significance in swine erysipelas.

Age-associated changes in the dopamine synthesis as determined by GTP cyclohydrolase I inhibitor in the brain of senescence-accelerated mouse-prone inbred strains (SAMP8)

Our objective in this study was to elucidate the mechanism underlying the decrease in dopamine (DA) levels in the brain with ageing We administered 2,4-diamino-6-hydroxypyrimidine (DAHP), an inhibitor of GTP cyclohydrolase I to senescence-accelerated mouse-prones (SAMP8), to inhibit DA and serotonin syntheses, and following immunohistochemical staining, analyzed the immunoreactive intensities (IR-Is) for DA in the nigrostriatal dopaminergic neurons by microphotometry. The DA-IR-Is in the substantia nigra pars compacta and neostriatum of young mice (2 months old) reached a minimal value 3 h after DAHP administration and returned to the control value 12 h after the administration. However, in aged mice (10 months old), the minimal value was reached 6 h after the administration and the value remained at approximately 70 and 80% of the control value at 24 and 72 h, respectively, after DAHP administration. The results suggest that DA turnover is lower in aged mice than in young mice.

Clinical, pathological and mineralogical features in two autopsy cases of workers exposed to agalmatolite dust

An agalmatolite miner and processor showed large shadows at the bilateral hila accompanied by surrounding emphysematous changes and irregular shadows on chest X-ray films. Chest CT scans were characterized by a mixture of tiny irregular structures and small round opacities. Histopathological examination revealed massive fibrosis, which corresponded to large shadows, but only a small number of typical silicotic nodules, indicating mixed dust pneumoconiosis. Mineralogical examination of the autopsy lungs showed quartz, pyrophyllite, mica, and kaolinite. Quartz accounted for 70% of the amount of all mineral dust in both patients, but pyrophyllite accounted for 10.8% and 14.4%. The pulmonary mineral dust composition in the two patients was well consistent with the mineral composition of the raw clays in the agalmatolite mine. In the two patients, chest X-ray findings and histopathological findings of the lungs also suggested agalmatolite pneumoconiosis, which was confirmed by mineral analysis of the lungs.

Eustachian tube cartilage and medial movement of lateral pharyngeal wall on phonation

Several authors have demonstrated the importance of medial movement of the lateral pharyngeal wall in velopharyngeal closure upon phonation. However, it remains controversial what muscle is responsible for lateral pharyngeal wall movement and where is the main site of this movement. The purpose of this study was to address the above two unanswered questions. In 22 subjects (12 normal volunteers, 10 patients with cleft palate), lateral pharyngeal wall movement upon phonation was evaluated by using rapid magnetic resonance imaging (MRI). Before rapid MRI, their lateral pharyngeal wall movements were classified into three groups: the poor, moderate, and good, according to the findings of nasopharyngoscopy. Inward displacement of the eustachian tube cartilages upon phonation, which was quantified as distance ratio in the transverse plane of MR images, was compared with nasopharyngoscopic findings. In addition, the level of lateral pharyngeal wall movement was observed in the plane 5 mm lateral to the mid-sagittal plane of MR images. Inward displacement of the eustachian tube cartilage in the transverse plane of MR images was coincident with medial movement of lateral pharyngeal wall observed by nasopharyngoscopy in all 22 subjects. By using one-way analysis of variance, a statistically significant correlation was found between nasopharyngoscopic classification and distance ratio. The sagittal plane of MR images revealed that the main site of movement occurred at the level of the hard palate and above. It is concluded that medial movement of the lateral pharyngeal wall consists of inward displacement of the eustachian tube cartilage, which is caused by contraction of the levator veli palatini muscle, and that the primary site of this movement is at the level of the hard palate and above, where the eustachian tube, but not the superior constrictor muscle, exists.

In vivo evaluation of a novel alginate dressing

Alginate dressings are currently used in the management of epidermal and dermal wounds, and provide a moist environment that leads to rapid granulation and reepithelialization. However, a cytotoxic effect on proliferation of fibroblasts and residual material with inflammation in healing wounds have been reported recently. We have developed a new alginate dressing (AGA-100), which does not have an inhibitory effect on proliferation of fibroblasts. The purpose of this study was to evaluate the new alginate dressing with respect to wound healing in full- and partial-thickness pig wounds and with respect to biodegradation following implantation into rabbit muscle. Kaltostat and Sorbsan, both well-established commercial dressings, were used as control. The closure rate of full-thickness wounds treated with AGA-100 was significantly higher on day 15 compared with that with Kaltostat and Sorbsan. Reepithelialization rate of partial-thickness wounds treated with Sorbsan was statistically significantly lower on day 3 than those with the other two dressings. As to dressing debris remained in the healing wound, a large amount of foreign debris was noted in all the full-thickness wounds treated with Kaltostat or Sorbsan, while only about one-third of wounds treated with AGA-100 showed a little dressing debris. AGA-100 implanted into the muscle of rabbits was bioresorbed completely within 3 months. Therefore, dressing residue in AGA-100-treated full-thickness wounds might be fully absorbed in a few months. In conclusion, it is shown that our newly developed AGA-100 possesses superior properties compared with typical alginate dressings.

Effect of acyclovir on bronchoconstriction and urinary leukotriene E4 excretion in aspirin-induced asthma

BACKGROUND

Acyclovir (9-[2-hydroxyethoxymethyl] guanine), an inhibitor of the DNA polymerase of the herpes virus, has been reported to exhibit pharmacologic activity other than antiviral activity, including antiasthmatic effects.

OBJECTIVE

This study was designed to investigate the protective effect of acyclovir on airway responsiveness to the sulpyrine provocation test and to investigate whether this protective activity is associated with a reduction in aspirin-induced excretion of urinary leukotriene E4 (u-LTE4 ), a marker of cysteinyl leukotriene (LT) overproduction that participates in the pathogenesis of aspirin-induced asthma.

METHODS

We assessed the effects of pretreatment with acyclovir on bronchoconstriction precipitated by inhalation of sulpyrine in 16 adult patients with mild or moderate aspirin-induced asthma; those who were in stable clinical condition and were hyperresponsive to the sulpyrine provocation test were allocated to this study. A double-blind, randomized, cross-over design was used. u-LTE4 was measured by a combined reverse-phase HPLC enzyme immunoassay.

RESULTS

Acyclovir protects against aspirin-induced attacks of asthma through mechanisms unrelated to its bronchodilator property but related to the improvement of bronchial hypersensitivity to sulpyrine; protection was nearly complete in all patients (P <.0001). By contrast, after acyclovir, the maximum level of u-LTE4 in patients was significantly lower than that in control subjects (P <. 01).

CONCLUSION

Our results suggest that acyclovir is not only an antiviral drug but also an inhibitor of analgesic-induced bronchoconstriction, probably acting by inhibiting the release of cysteinyl LTs.

Bronchial hyperresponsiveness, hypersensitivity to analgesics and urinary leukotriene E4 excretion in patients with aspirin-intolerant asthma

This study was designed to investigate the protective effect of cromolyn sodium on airway sensitivity to sulpyrine, and bronchial responsiveness to methacholine, and to investigate whether this protective activity is associated with reduction in aspirin-induced excretion of urinary leukotriene E4 (u-LTE4), a marker of the cysteinyl LT overproduction that participates in the pathogenesis of aspirin-induced asthma. We assessed the effects of pretreatment with cromolyn sodium on bronchoconstriction precipitated by inhalation of methacholine and sulpyrine in 16 adult patients with mild or moderate aspirin-intolerant asthma; those who were in stable clinical condition and were hypersensitive to a sulpyrine provocation test were included in this study. A double-blind, randomized, crossover design was used. u-LTE4 was measured using combined reverse-phase high-performance liquid chromatography enzyme immunoassay. Cromolyn sodium protected against analgesic-induced bronchoconstriction through mechanisms that are not related to its bronchodilator property, but to the improvement of both bronchial hyperresponsiveness and hypersensitivity to analgesics (p<0.01 and p<0.001). Although excretion of u-LTE4 did not increase after the methacholine provocation test, it significantly increased after sulpyrine provocation (p<0.01). Furthermore, after pretreatment with cromolyn sodium, the maximum level of u-LTE4 after the sulpyrine provocation test was significantly lower than in controls (p<0.01). These results support the hypothesis that cysteinyl LT is one of the most important components in the pathogenesis of aspirin-intolerant asthma. Cromolyn sodium improves both hypersensitivity to analgesics, and bronchial hyperresponsiveness in aspirin-intolerant asthma.

Evaluation of a novel alginate gel dressing: cytotoxicity to fibroblasts in vitro and foreign-body reaction in pig skin in vivo

Calcium alginate dressings have beneficial effects on wound healing by providing a moist wound environment. However, cytotoxicity and the nonbiodegradable nature of calcium alginate dressings induce unresolved chronic foreign-body reaction. In this study, a novel freeze-dried alginate gel dressing (AGA-100) low in calcium ions was evaluated for cytotoxicity to L929 cells in vitro and in full-thickness pig wounds in vivo. Cytotoxicity testing on L929 cells showed the cytocompatibility of AGA-100 extracts, while extracts from Kaltostat, a well-established alginate dressing, induced cytopathic effects. In an in vivo study using pigskin, AGA-100, Kaltostat, and gauze were applied on 1-in-diameter circular full-thickness wounds on the back of pigs and the time course of wound closure was evaluated. Kaltostat and gauze dressings were used as controls. For histologic evaluation, wound tissue was harvested on day 18. AGA-100-treated wounds showed rapid wound closure compared to control wounds on day 15. Foreign-body reaction was marked in Kaltostat- and gauze-treated wounds, and differed significantly from AGA-100-treated wounds. Based on these data, AGA-100 could reduce the cytotoxicity to fibroblasts and foreign-body reaction that have been observed with currently available calcium alginate dressings; it was also found to be useful as an alginate dressing.

Immunohistochemical colocalization of GTP cyclohydrolase I in the nigrostriatal system with tyrosine hydroxylase

Immunohistochemical colocalization of GTP cyclohydrolase I (GCH) in the mouse nigrostriatal system with tyrosine hydroxylase or aromatic L-amino acid decarboxylase in the somata and terminals of GCH-positive catecholaminergic neurons are proved for the first time by a double-labeling immunofluorescence method with a confocal laser-scanning microscope. GCH-immunoreactive somata in the mouse substantia nigra have synaptic contacts with monoaminergic and non-monoaminergic terminals.

Nonpathological focal enhancements on spiral CT hepatic angiography

BACKGROUND

To assess the frequency and characteristics of nonpathological focal enhancements seen on spiral computed tomographic (CT) hepatic angiography (CTA).

METHODS

Spiral CTA and spiral CT arterial portography (CTAP) were performed in 31 patients with suspected liver malignancy prior to potential liver resection. The CTA images were retrospectively reviewed for focal enhancements by two radiologists. After determining nonpathological focal enhancements on CTA images based on the other radiographic tests, surgical exploration including intraoperative sonography, follow-up imagings, the frequency, size, site, and shape of nonpathological focal enhancements with CTA were assessed.

RESULTS

Thirty-six nonpathological focal enhancements with CTA from 4 to 23 (mean = 11. 4) mm were seen in 14 (45.2%) of 31 patients. Thirteen (36.1%) of 36 nonpathological focal enhancements with CTA were not depicted with CTAP. Nonpathological focal enhancements with CTA were frequent in Couinaud segments III (27.8%), V (22.2%), and VI (19.4%). Twenty-three (63.9%) of 36 nonpathological focal enhancements were located in the edge of the liver. Shapes of 36 nonpathological focal enhancements with CTA included circular (n = 16), worm (n = 7), irregular (n = 6), dot (n = 6), and wedge (n = 1).

CONCLUSION

In nearly half of patients, spiral CTA shows various shapes of small nonpathological focal enhancements more frequently in the liver edge.

Demonstration of false-negative findings on CT hepatic angiography

False-negative findings on CT angiography (CTA) in two patients with hepatocellular carcinoma (HCC) were demonstrated. CTA images of one patient with an aberrant left hepatic artery branching from the left gastric artery and another patient whose right hepatic artery was occluded owing to an unknown cause failed to demonstrate HCCs. This report suggests one of the diagnostic pitfalls of CTA for diagnosis of liver tumors.

Renal pelvic and ureteral carcinoma with huge hydronephrosis: US, CT, and MR findings

A 78-year-old man presented huge hydronephrosis with a calculus in the left kidney, and underwent left nephroureterectomy under the diagnosis of renal pelvic and ureteral tumor. Histological examination disclosed renal pelvic and ureteral tumors featuring mixed histologic types of carcinoma. Magnetic resonance (MR) imaging was superior to computed tomography (CT) in its complete, detailed demonstration of the renal pelvic lesions. The imaging characteristics of CT, MR imaging, ultrasonography, and retrograde ureterography were discussed in the report.

Velopharyngeal closure and the longus capitis muscle

The dynamic mechanism of velopharyngeal function not only in normal individuals but also in patients with velopharyngeal insufficiency, which is mainly related to cleft palate, has been the subject of considerable interest and controversy. Recently, in order to clarify velopharyngeal movement in the valvular action on phonation we examined dynamic MR images of this area taken in the transverse plane in parallel with the muscle sling of levator veli palatini. In cases in whom the closure pattern in that plane is circular, detailed observation revealed a very interesting result; that is, the longus capitis muscle, one of the group of anterior vertebral muscles, is directly involved in velopharyngeal valving function. It has not previously been reported that the longus capitis muscle acts as one of the velopharyngeal closure muscles, in addition to levator veli palatini. The present study demonstrated that contraction of the muscle contributed to velopharyngeal closure by forward movement of the pharyngeal wall.

Transient appearance of tyrosine hydroxylase-immunoreactive non-catecholaminergic neurons in the medial geniculate nucleus of postnatal mice

Tyrosine hydroxylase-immunoreactive (TH-ir) cells were found to appear transiently in the medial geniculate nuclear region of mice at postnatal day 7 (P7) by use of an avidin-biotin peroxidase complex (ABC) method for the first time. The numbers of TH-ir cells reached maximum between P14 and P21 and decreased until P29. These cells were GTP cyclohydrolase I-negative, aromatic L-amino acid decarboxylase-negative, and dopamine-negative. Thus, they do not belong to the catecholaminergic neuron system, because they lack dopamine production. The results suggest that TH in the cells in the medial geniculate nuclear region of mice has some new functions besides catecholamine biosynthesis.

Value of three-dimensional spiral CT hepatic angiography

OBJECTIVE

The aim of this study was to compare with conventional angiography images the diagnostic utility of three-dimensional CT hepatic angiography (CTHA) images reconstructed from spiral CT images obtained during direct injection of contrast material into hepatic arteries.

MATERIALS AND METHODS

Three-dimensional CTHA images were reconstructed from spiral CTHA images obtained during direct hepatic arterial contrast material injection in 22 patients. We used maximum-intensity-projection (MIP) and shaded-surface-display (SSD) techniques. We compared matched pairs of MIP CTHA images and SSD CTHA images with conventional angiograms for depiction of peripheral (segmental to subsegmental order branches) and proximal (common to proper) hepatic arteries as well as for conspicuity of the entire hepatic arterial tree in 22 patients and for conspicuity of tumors, recognition of tumor sites, and depiction of tumor-feeding arteries in 21 patients with malignant liver tumors. Our evaluations were performed in a blinded fashion by two experienced radiologists, who reached a consensus. (These radiologists also counted the number of tumors depicted by each method in the 21 patients with malignant liver tumors.)

RESULTS

Depiction of peripheral and proximal hepatic arteries and conspicuity of the entire hepatic arterial tree were significantly better on conventional angiograms than on MIP CTHA images and SSD CTHA images. Conspicuity of tumors and recognition of tumor sites were significantly better on MIP CTHA images and SSD CTHA images than on conventional angiograms. Depiction of tumor-feeding arteries was significantly better on MIP CTHA images than on SSD CTHA images and conventional angiograms. For 47 malignant liver tumors, MIP CTHA images showed 40 (85%), SSD CTHA images showed 34 (72%), and conventional angiograms showed 20 (43%).

CONCLUSION

MIP CTHA images showed liver tumors, tumor sites, and tumor-feeding arteries better than conventional angiograms. MIP was the preferred method for three-dimensional CTHA analysis.

Hemodynamics of small hepatocellular carcinomas (5 cm or less in diameter): cases with discrepant findings between dynamic MR images and hepatic arteriograms

BACKGROUND

The degrees and patterns of contrast enhancement of small hepatocellular carcinomas (HCCs) on dynamic magnetic resonance (MR) images were compared with those on hepatic arteriograms in 61 patients.

METHODS

Dynamic MR imaging was performed within 1 week before hepatic angiography prior to treatment, 3-4 weeks after treatment, and then once every 1-3 months if necessary. Hepatic arteriography was carried out with a coaxial microcatheter inserted into the proper hepatic artery or its distal branches.

RESULTS

In 58 of 61 cases, the degrees of contrast enhancement of the tumor in dynamic MR imaging were roughly consistent with those in hepatic arteriography before treatment. In the remaining three cases, however, the tumors were depicted as hyperintense in the arterial dominant phase of the dynamic MR imaging, whereas the tumors were not detected by hepatic arteriography. The tumor detectability is 97% by dynamic MR imaging and 92% by hepatic arteriography. Furthermore, when an HCC nodule was not clearly enhanced by hepatic arteriography after treatment, it was possible by dynamic MR imaging to obtain accurate information on whether the HCC nodule had parasitic arteries.

CONCLUSIONS

Dynamic MR imaging was superior to hepatic angiography in contrast resolution. It was therefore considered to be useful in assessing the degrees and patterns of contrast enhancement of small HCCs before and after treatment.

Dynamic MRI of the diaphragm

OBJECTIVE

To demonstrate the appearance of the diaphragm on single-slice dynamic MRI.

MATERIALS AND METHODS

We evaluated the diaphragm using gadolinium-enhanced single-slice dynamic MR in 53 patients.

RESULTS

The diaphragm was partially depicted in 49 cases (92.5%). Its thickest part measured 4.4 +/- 2.2 mm, range 3 to 15 mm. Enhanced high-intensity thin layer structures were partially identified between the diaphragm and liver parenchyma in 46 cases (86.8%) at 16 to 144 s (mean +/- SD, 65.7 +/- 32.6 s) after intravenous injection of Gd-DTPA.

CONCLUSION

Dynamic MR has value and limitations in demonstrating the diaphragm.