Features and mechanisms of propofol-induced protein kinase C (PKC) translocation and activation in living cells

Background and purpose: In this study, we aimed to elucidate the action mechanisms of propofol, particularly those underlying propofol-induced protein kinase C (PKC) translocation. Experimental approach: Various PKCs fused with green fluorescent protein (PKC-GFP) or other GFP-fused proteins were expressed in HeLa cells, and their propofol-induced dynamics were observed using confocal laser scanning microscopy. Propofol-induced PKC activation in cells was estimated using the C kinase activity receptor (CKAR), an indicator of intracellular PKC activation. We also examined PKC translocation using isomers and derivatives of propofol to identify the crucial structural motifs involved in this process. Key results: Propofol persistently translocated PKCα conventional PKCs and PKCδ from novel PKCs (nPKCs) to the plasma membrane (PM). Propofol translocated PKCδ and PKCη of nPKCs to the Golgi apparatus and endoplasmic reticulum, respectively. Propofol also induced the nuclear translocation of PKCζ of atypical PKCs or proteins other than PKCs, such that the protein concentration inside and outside the nucleus became uniform. CKAR analysis revealed that propofol activated PKC in the PM and Golgi apparatus. Moreover, tests using isomers and derivatives of propofol predicted that the structural motifs important for the induction of PKC and nuclear translocation are different. Conclusion and implications: Propofol induced the subtype-specific intracellular translocation of PKCs and activated PKCs. Additionally, propofol induced the nuclear translocation of PKCs and other proteins, probably by altering the permeability of the nuclear envelope. Interestingly, propofol-induced PKC and nuclear translocation may occur via different mechanisms. Our findings provide insights into the action mechanisms of propofol.

Identification of protein kinase C domains involved in its translocation induced by propofol

Propofol is widely used for general anesthesia and sedation; however, the mechanisms of its anesthetic and adverse effects are not fully understood. We have previously shown that propofol activates protein kinase C (PKC) and induces its translocation in a subtype-specific manner. The purpose of this study was to identify the PKC domains involved in propofol-induced PKC translocation. The regulatory domains of PKC consist of C1 and C2 domains, and the C1 domain is subdivided into the C1A and C1B subdomains. Mutant PKCα and PKCδ with each domain deleted were fused with green fluorescent protein (GFP) and expressed in HeLa cells. Propofol-induced PKC translocation was observed by time-lapse imaging using a fluorescence microscope. The results showed that persistent propofol-induced PKC translocation to the plasma membrane was abolished by the deletion of both C1 and C2 domains in PKCα and by the deletion of the C1B domain in PKCδ. Therefore, propofol-induced PKC translocation involves the C1 and C2 domains of PKCα and the C1B domain of PKCδ. We also found that treatment with calphostin C, a C1 domain inhibitor, abolished propofol-induced PKCδ translocation. In addition, calphostin C inhibited the propofol-induced phosphorylation of endothelial nitric oxide synthase (eNOS). These results suggest that it may be possible to modulate the exertion of propofol effects by regulating the PKC domains involved in propofol-induced PKC translocation.

Characterization of intracellular calcium mobilization induced by remimazolam, a newly approved intravenous anesthetic

Many anesthetics, including Propofol, have been reported to induce elevation of intracellular calcium, and we were interested to investigate the possible contribution of calcium elevation to the mechanism of the newly approved remimazolam actions. Remimazolam is an intravenous anesthetic first approved in Japan in July 2020, and is thought to exert its anesthetic actions via γ-aminobutyric acid A (GABAA) receptors; however, the precise mechanisms of how remimazolam elevates intracellular calcium levels remains unclear. We examined the remimazolam-induced elevation of intracellular calcium using SHSY-5Y neuroblastoma cells, COS-7 cells, HEK293 cells, HeLa cells, and human umbilical vein endothelial cells (HUVECs) loaded with fluorescent dyes for live imaging. We confirmed that high concentrations of remimazolam (greater than 300 μM) elevated intracellular calcium in a dose-dependent manner in these cells tested. This phenomenon was not influenced by elimination of extracellular calcium. The calcium elevation was abolished when intracellular or intraendoplasmic reticulum (ER) calcium was depleted by BAPTA-AM or thapsigargin, respectively, suggesting that calcium was mobilized from the ER. Inhibitors of G-protein coupled receptors (GPCRs)-mediated signals, including U-73122, a phospholipase C (PLC) inhibitor and xestospongin C, an inositol 1,4,5-triphosphate receptors (IP3R) antagonist, significantly suppressed remimazolam-induced calcium elevation, whereas dantrolene, a ryanodine receptor antagonist, did not influence remimazolam-induced calcium elevation. Meanwhile, live imaging of ER during remimazolam stimulation using ER-tracker showed no morphological changes. These results suggest that high doses of remimazolam increased intracellular calcium concentration in a dose-dependent manner in each cell tested, which was predicted to be caused by calcium mobilization from the ER. In addition, our studies using various inhibitors revealed that this calcium elevation might be mediated by the GPCRs-IP3 pathway. However, further studies are required to identify which type of GPCRs is involved.

Assessment of postoperative nutritional status and physical function between open surgical aortic valve replacement and transcatheter aortic valve implantation in elderly patients

Background and aims : Severe aortic stenosis (AS) has been normally treated with surgical aortic valve replacement (AVR) whereas recently, transcatheter aortic valve implantation (TAVI) has been introduced as a minimally invasive operation for patients with high surgical risk and frailty. In this study, we have evaluated postoperative physical function and nutrition intake in the patients following AVR and TAVI. Methods : This prospective observational study involved 9 patients with surgical aortic valve replacement (AVR) and 7 patients with transcatheter aortic valve implantation (TAVI). Body composition was measured one day prior surgery, postoperative day (POD) 1, POD 3, POD 5 and POD 7. Hand grip strength, calf circumference and gait speed were measured one day before surgery and on the day of discharge. Results : Skeletal muscle was significantly decreased in AVR patients at postoperative day 3 and 7, while there was no change in TAVI patients. Patients with TAVI showed higher dietary intake after surgery compared to patients with AVR, and they maintained hand grip strength and calf circumference at discharge. Conclusions : In elderly patients with AS, TAVI can improve post-operative recovery maintaining nutritional status and physical function even. J. Med. Invest. 67 : 139-144, February, 2020.

SKF-10047, a prototype Sigma-1 receptor agonist, augmented the membrane trafficking and uptake activity of the serotonin transporter and its C-terminus-deleted mutant via a Sigma-1 receptor-independent mechanism

The serotonin transporter (SERT) is functionally regulated via membrane trafficking. Our previous studies have demonstrated that the SERT C-terminal deletion mutant (SERTΔCT) showed a robust decrease in its membrane trafficking and was retained in the endoplasmic reticulum (ER), suggesting that SERTΔCT is an unfolded protein that may cause ER stress. The Sigma-1 receptor (SigR1) has been reported to attenuate ER stress via its chaperone activity. In this study, we investigated the effects of SKF-10047, a prototype SigR1 agonist, on the membrane trafficking and uptake activity of SERT and SERTΔCT expressed in COS-7 cells. Twenty-four hours of SKF-10047 treatment (>200 μM) accelerated SERT membrane trafficking and robustly upregulated SERTΔCT activity. Interestingly, these effects of SKF-10047 on SERT functions were also found in cells in which SigR1 expression was knocked down by shRNA, suggesting that SKF-10047 exerted these effects on SERT via a mechanism independent of SigR1. A cDNA array study identified several candidate genes involved in the mechanism of action of SKF-10047. Among them, Syntaxin3, a member of the SNARE complex, was significantly upregulated by 48 h of SKF-10047 treatment. These results suggest that SKF-10047 is a candidate for ER stress relief.

[The Analgesic Sparing Effect of Ketamine for Postoperative Pain Management after Pediatric Surgery on the Body Surface]

BACKGROUND

It is reported that ketamine, a N-methyl-D-aspertate (NMDA) receptor antagonist, can provide analgesic effect improving postoperative pain management and decrease the supplementary analgesic requirement. We investigated the analgesic sparing effect of ketamine for postoperative pain in children undergoing surgery of body surface.

METHODS

Fifty eight patients (0-9 yrs) who had surgery of body surface were divided into two groups (ketamine : n = 27, Group K or control : n = 31, Group N). Postoperative analgesia extracted from charts was retrospectively evaluated by the times patients used analgesics until discharge after the operations. Chi-square and Mann-Whitney U tests were used for statistical analysis. Results : The ketamine group received an intrave- nous bolus of ketamine (1 mg - kg-1) before surgical skin incision. However, there were no significant differ- ences of usage (Group K vs Group N : 4/27 vs 7/31, P=0.45) and frequency of supplementary analgesic us- ages (P=0.85) among groups. In addition, there were also no significant demographic differences between the two groups. Conclusions : Our investigation suggests that the intravenous bolus of ketamine (1 mg - kg-1) before surgical skin incision does not decrease the supple- mentary analgesic requirements on postoperative pain management in pediatric surgery of the body surface.

[The Influence of Flurbiprofen on the Frequency of Postoperative Shivering]

BACKGROUND

Many methods to prevent postoperative shivering (POS) has been reported. However, there are few reports demonstrating the effect of flurbiprofen on POS which affects the set point in the thermocenter of the hypothalamus.

METHODS

One hundred and forty six patients undergoing lung lobectomy or segmentectomy under video-assisted thoracic surgery were divided into a flurbiprofen-treated group (Group F) and a non-treated group (Group N). We retrospectively investigated the incidence of POS associated with total intravenous anesthesia with epidural anesthesia compared with or without flurbiprofen. We weighed the incidence of POS against age, body mass index, the effective site concentration of fentanyl on extubation, the mean dose of remifentanil, the minimum rectal temperature, the surgical duration and total hemorrhage volume based on the anesthetic chart Chi-square and Student t-test were used for statistical analysis.

RESULTS

Although the surgical duration in Group F was shorter than that in Group N (223±83 vs. 165±80 (min), P<0.01), the incidence of POS in Group F was higher than that in Group N (1/32 vs. 28/114, P<0.01). There were no significant differences in another items between the two groups.

CONCLUSIONS

The results of the study indicates that flurbiprofen has a possible beneficial effect in preventing POS.

Type 2 diabetes reduces the proliferation and survival of oligodendrocyte progenitor cells in ishchemic white matter lesions

Diabetes mellitus (DM) is a major risk factor for stroke and it exacerbates tissue damage after ischemic insult. Diabetes is one of the important causes of the progression of white matter lesion, however, the pathological mechanisms remain unclear. The present study evaluated the influences of type 2 DM on ischemic subcortical white matter injury and the recruitment of oligodendrocyte progenitor cells (OPCs) under chronic cerebral hypoperfusion using type 2 diabetic (db/db) mice. After bilateral common carotid artery stenosis (BCAS), the rarefaction in the white matter was more severe in db/db mice than in db/+ mice, and the number of glutathione S-transferase-pi (GST-pi)-positive mature oligodendrocytes (OLG) was lower in db/db mice than in db/+ mice at 4 and 8 weeks after ischemia. There were no significant differences in the number of single-stranded DNA (ssDNA)-positive apoptotic cells in the deep white matter between the db/db and db/+ mice. We found a transient increase in the platelet-derived growth factor receptor-α (PDGFRα)-positive OPCs in white matter lesions after ischemia. However, significantly fewer PDGFRα-positive OPCs were detected in db/db than db/+ mice from 4weeks after BCAS. The number of Ki67-positive proliferating cells in the deep white matter was significantly lower in db/db mice than in db/+ mice from 4 to 8weeks after BCAS. Most of the Ki67-positive cells were PDGFRα-positive OPCs. Finally, we assessed the survival of 5-bromo-2'-deoxyuridine (BrdU)-positive proliferating cells in ischemic white matter, and found significantly poorer survival of BrdU/PDGFRα-positive OPCs or BrdU/GST-pi-positive OLGs in the db/db mice compared to the db/+ mice in the white matter after BCAS. Our findings suggest that the type 2 DM mice exhibited more severe white matter injury 8 weeks after chronic ischemia. Decreased proliferation and survival of OPCs may play an important role in the progression of white matter lesions after ischemia in diabetics.

[Case of drug-induced angioedema (DIAE) on induction of anesthesia with difficult ventilation due to oropharyngeal edema]

A 69-year-old man with a past history of hypertension on angiotensin II receptor blocker (ARB) for three months presented for radical prostatectomy. Immediately after induction of anesthesia with fentanyl and propofol, mask ventilation became difficult, although no significant hemodynamic changes occurred. Fiberoptic examination revealed severe oropharyngeal edema, but, the trachea was successfully intubated. Afterward, the operation proceeded without complications. He stayed in the ICU for 4 days until the trachea was extubated successfully. He was diagnosed with DIAE because of his history of dyspnea with exclusion of other possible pathophysiological conditions.

Visceral fat accumulation is associated with cerebral small vessel disease

BACKGROUND AND PURPOSE

Obesity is associated with the risk of coronary artery disease and stroke. Visceral fat plays a significant role in the atherogenic effects of obesity. Whether visceral fat accumulation, as measured by computed tomography (CT), is an independent risk factor for the presence of cerebral small vessel disease (SVD) was investigated.

METHODS

This study comprised 506 Japanese subjects 35-74 years of age (mean 55.3 years) without a history of symptomatic cerebrovascular disease who underwent health screening tests, including brain magnetic resonance imaging, carotid echography and measurements of the visceral fat area (VFA) and subcutaneous fat area (SFA) on abdominal CT. Visceral fat accumulation was defined as VFA ≥ 100 cm(2) . Logistic regression analysis was performed to examine the associations between visceral fat accumulation and cerebral SVD such as white matter lesions (WMLs) and silent lacunar infarction (SLI).

RESULTS

The prevalence of WMLs and SLI but not carotid plaque were significantly higher in subjects with VFA ≥ 100 cm(2) than those with VFA < 100 cm(2) . A VFA ≥ 100 cm(2) was associated with WMLs and SLI independent of age, cardiovascular risk factors and other measurements of obesity, such as waist circumference and body mass index. A large waist circumference was independently associated with SLI. SFA, the combination of VFA and SFA, and body mass index were not associated with WMLs or SLI.

CONCLUSIONS

Visceral fat accumulation was independently associated with the presence of cerebral SVD in subjects without a history of symptomatic cerebrovascular disease.

Chronic brain ischemia induces the expression of glial glutamate transporter EAAT2 in subcortical white matter

Glutamate plays a central role in brain physiology and pathology. The involvement of excitatory amino acid transporters (EAATs) in neurodegenerative disorders including acute stroke has been widely studied, but little is known about the role of glial glutamate transporters in white matter injury after chronic cerebral hypoperfusion. The present study evaluated the expression of glial (EAAT1 and EAAT2) and neuronal (EAAT3) glutamate transporters in subcortical white matter and cortex, before and 3-28 days after the ligation of bilateral common carotid arteries (LBCCA) in rat brain. K-B staining showed a gradual increase of demyelination in white matter after ischemia, while there was no cortical involvement. Between 3 and 7 days after LBCCA, a significant increase in EAAT2 protein levels was observed in the ischemic brain and the number of EAAT2-positive cells also significantly increased both in the cortical and white matter lesions. EAAT2 was detected in glial-fibrillary acidic protein (GFAP)-positive astrocytes in both the cortex and white matter, but not in neuronal and oligodendroglial cells. EAAT1 was slightly elevated after ischemia only in the white matter, but EAAT3 was at almost similar levels both in the cortex and white matter after ischemia. A significant increase in EAAT2 expression level was also noted in the deep white matter of chronic human ischemic brain tissue compared to the control group. Our findings suggest important roles for up-regulated EAAT2 in chronic brain ischemia especially in the regulation of high-affinity of extracellular glutamate and minimization of white matter damage.

Cilostazol attenuates ischemic brain injury and enhances neurogenesis in the subventricular zone of adult mice after transient focal cerebral ischemia

Evidence suggests that neurogenesis occurs in the adult mammalian brain, and that various stimuli, for example, ischemia/hypoxia, enhance the generation of neural progenitor cells in the subventricular zone (SVZ) and their migration into the olfactory bulb. In a mouse stroke model, focal ischemia results in activation of neural progenitor cells followed by their migration into the ischemic lesion. The present study assessed the in vivo effects of cilostazol, a type 3 phosphodiesterase inhibitor known to activate the cAMP-responsive element binding protein (CREB) signaling, on neurogenesis in the ipsilateral SVZ and peri-infarct area in a mouse model of transient middle cerebral artery occlusion. Mice were divided into sham operated (n=12), vehicle- (n=18) and cilostazol-treated (n=18) groups. Sections stained for 5-bromodeoxyuridine (BrdU) and several neuronal and a glial markers were analyzed at post-ischemia days 1, 3 and 7. Cilostazol reduced brain ischemic volume (P<0.05) and induced earlier recovery of neurologic deficit (P<0.05). Cilostazol significantly increased the density of BrdU-positive newly-formed cells in the SVZ compared with the vehicle group without ischemia. Increased density of doublecortin (DCX)-positive and BrdU/DCX-double positive neural progenitor cells was noted in the ipsilateral SVZ and peri-infarct area at 3 and 7 days after focal ischemia compared with the vehicle group (P<0.05). Cilostazol increased DCX-positive phosphorylated CREB (pCREB)-expressing neural progenitor cells, and increased brain derived neurotrophic factor (BDNF)-expressing astrocytes in the ipsilateral SVZ and peri-infarct area. The results indicated that cilostazol enhanced neural progenitor cell generation in both ipsilateral SVZ and peri-infarct area through CREB-mediated signaling pathway after focal ischemia.

Crucial role for Ser133-phosphorylated form of cyclic AMP-responsive element binding protein signaling in the differentiation and survival of neural progenitors under chronic cerebral hypoperfusion

Various stimuli, such as ischemia/hypoxia enhance newborn cell survival in the subventricular zone and their migration tangentially in chains toward the olfactory bulb. The present study assessed the fate of newborn neurons from subventricular zone to olfactory bulb under conditions of chronic cerebral hypoperfusion, and examined the role of cAMP-responsive element binding protein signaling on the survival of these neurons by using cilostazol, a potent inhibitor of type III phosphodiesterase. Rats underwent bilateral common carotid artery ligation. They were divided into sham-operated (n=70), vehicle- (n=70), and type III phosphodiesterase inhibitor-treated (n=70) groups. Immunohistochemically-stained section for 5-bromodeoxyuridine and a series of neuronal and glial markers were analyzed at days 7, 14, 21 and 28 after hypoperfusion. The reduction of olfactory bulb size gradually progressed in the vehicle group (P<0.05), but not in the sham-operated and type III phosphodiesterase inhibitor-treated group. The subventricular zone of the vehicle-treated rats contained significantly larger numbers of newborn neuroblasts after hypoperfusion, compared with sham-operated rats (P<0.05), but significantly lower numbers in the rostral migratory stream and olfactory bulb (P<0.05). Treatment of rats with type III phosphodiesterase inhibitor increased the number of neuroblasts and enhanced the survival and differentiation of cells (P<0.05). Phosphorylated cAMP-responsive element binding protein within neuroblasts was markedly decreased in the subventricular zone, rostral migratory stream, and olfactory bulb of vehicle-treated rats (P<0.05), but treatment with type III phosphodiesterase inhibitor resulted in recovery of this expression throughout hypoperfusion, leading to enhanced neurogenesis (P<0.05). These effects were abrogated by protein kinase A and C inhibitor. Our results indicated that cAMP-responsive element binding protein signaling is a key mediator of neurogenesis after prolonged hypoperfusion and provide the basis for new regenerative therapies for ischemic brain injury.

Chronic osmotic stimuli increase salusin-beta-like immunoreactivity in the rat hypothalamo-neurohypophyseal system: possible involvement of salusin-beta on [Ca2+]i increase and neurohypophyseal hormone release from the axon terminals

Salusin-alpha and -beta were recently discovered as bioactive endogenous peptides. In the present study, we investigated the effects of chronic osmotic stimuli on salusin-beta-like immunoreactivity (LI) in the rat hypothalamo-neurohypophyseal system. We examined the effects of salusin-beta on synaptic inputs to the rat magnocellular neurosecretory cells (MNCs) of the supraoptic nucleus (SON) and neurohypophyseal hormone release from both freshly dissociated SONs and neurohypophyses in rats. Immunohistochemical studies revealed that salusin-beta-LI neurones and fibres were markedly increased in the SON and the magnocellular division of the paraventricular nucleus after chronic osmotic stimuli resulting from salt loading for 5 days and dehydration for 3 days. Salusin-beta-LI fibres and varicosities in the internal zone of the median eminence and the neurohypophysis were also increased after osmotic stimuli. Whole-cell patch-clamp recordings from rat SON slice preparations showed that salusin-beta did not cause significant changes in the excitatory and inhibitory postsynaptic currents of the MNCs. In vitro hormone release studies showed that salusin-beta evoked both arginine vasopressin (AVP) and oxytocin release from the neurohypophysis, but not the SON. In our hands, in the neurohypophysis, a significant release of AVP and oxytocin was observed only at concentrations from 100 nm and above of salusin-beta. Low concentrations below 100 nm were ineffective both on AVP and oxytocin release. We also measured intracellular calcium ([Ca(2+)](i)) increase induced by salusin-beta on freshly-isolated single nerve terminals from the neurohypophysis devoid of pars intermedia. Furthermore, this salusin-beta-induced [Ca(2+)](i) increase was blocked in the presence of high voltage activated Ca(2+)channel blockers. Our results suggest that salusin-beta may be involved in the regulation of body fluid balance by stimulating neurohypophyseal hormone release from nerve endings by an autocrine/paracrine mechanism.

Stromal reaction of adenomyosis protects from uterine endometrial cancer invasion to myometrium

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Background: It is unclear that stromal reaction plays role in endometrial cancer (Em Ca) invasion to uterine muscle with adenomyosis. Methods: One hundred and five patients with Em Ca (stage 0=38, 1a=18, 1b=26, 1c=10, 2b=3, 3a=4, 3c=5, 4a=1) received operative therapy with hysterectomy. Evaluation of stromal reaction using immunohistochemical method with alpha-smooth muscle actin and h-caldesmon antibody. In case of alpha-smooth muscle actin had immunoreactivity and h-caldesmon had not immunoreactivity, there was stromal reaction with myofibroblast. Evaluation of cell proliferation, using immunohistochemical method with epidermal growth factor receptor (EGFR) by global score with six degrees and MIB-1 by labeling Index (LI). Results: All cases had stromal reaction with myofibloblast in myometrial invasion area in forty nine cases with myometrial invasion equal or more than stage 1b. Em Ca invaded near to and in adenomyosis lesion in eleven cases. In stroma of adenomyosis without cancer invasion, EGFR was positive in one case (9%) and global score was two (average 0.18). In contrast, EGFR was positive in eight cases (73%) with Em Ca invasion to adenomyosis stroma and global score was from two to three (average 1.6). LI of MIB-1 was from 0 to 0.2 (average 0.05) in adenomyosis stroma without Em Ca invasion and 0.2 to 0.75 (average 0.41) with Em Ca invasion. Conclusions: When Em Ca invades to adenomyosis, myofibloblast cell proliferation in stromal reaction increases more than in adenomyosis without Em Ca invasion. Stromal reaction of adenomyosis plays role in protecting from Em Ca invasion to uterine muscle and it may contribute to being good prognosis compared with Em Ca without adenomyosis.

No significant financial relationships to disclose.

Induction and selective accumulation of mutant ubiquitin in CA1 pyramidal neurons after transient global ischemia

Accumulation of mutant ubiquitin-B (UBB(+1)) in neurons is considered the hallmark of proteasomal dysfunction in neurodegenerative disorders, however no such evidence in ischemic brain has been reported. We investigated the contribution of UBB(+1) in delayed neuronal death after transient global ischemia. Transient global ischemia was achieved by occlusion of bilateral common carotid arteries for 5 min and reperfusion in male Mongolian gerbils (n=6 per each time point). In the CA1 region, UBB(+1) immunoreactivity appeared in the cytoplasm of pyramidal cells at 30 min post-ischemia, and the density of these neurons increased at day 2 (P<0.001) and further increased at day 4 post-ischemia. Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL)-positive (apoptotic) cells appeared selectively in the CA1 region at day 3 and their density increased further at day 4 post-ischemia (P<0.001). In contrast, UBB(+1) immunoreactivity was only transiently detected from 30 min to 1 day post-ischemia in CA3, dentate gyrus, and frontal cortex, but disappeared at day 2 post-ischemia. No TUNEL-positive cells were observed in these three regions. UBB(+1) mRNA was detected by reverse transcription-polymerase chain reaction in every region of the hippocampus and frontal cortex of ischemic gerbils and even in the non-ischemic control animals, and its expression level was independent of brain region and time after ischemia. Our results indicate induction and selective accumulation of UBB(+1) protein in dying neurons of the CA1 region and suggest that UBB(+1) expression may be induced by proteasomal dysfunction after transient global ischemia.

Focal cerebral ischemia/reperfusion injury in mice induces hematopoietic prostaglandin D synthase in microglia and macrophages

Hematopoietic prostaglandin D synthase is a key enzyme in synthesis of prostaglandin D. Hematopoietic prostaglandin D synthase is expressed in microglia of the developing mouse brain. This study determined the serial changes and cellular localization of hematopoietic prostaglandin D synthase, and its role in cerebral ischemia/reperfusion injury using C57BL/6 mice (n=84) and bone marrow chimera mice (n=16). The latter mice were selected based on their expression of enhanced green fluorescent protein in bone marrow/blood-derived monocytes/macrophages. The middle cerebral artery was occluded for 60 min, followed by reperfusion. Hematopoietic prostaglandin D synthase expression was examined by immunohistochemistry and Western blotting. Hematopoietic prostaglandin D synthase-positive cells were mainly expressed in the peri-ischemic area at 12 h (P<0.05) and 24 h (P<0.001) after reperfusion, while they were mostly found in the transition area at 48-72 h postreperfusion (P<0.001). There was a significant increase in staining intensity as well as number of hematopoietic prostaglandin D synthase-positive cells in the ischemic core at 5-7 (P<0.001) days postreperfusion. Hematopoietic prostaglandin D synthase-positive cells also co-expressed ionized calcium-binding adapter molecule 1, a marker of microglia/macrophages, and cyclooxygenase-2, but not markers of neurons, oligodendrocytes and astrocytes. Until 72 h postreperfusion, many enhanced green fluorescent protein-positive cells were negative for hematopoietic prostaglandin D synthase, but the number of hematopoietic prostaglandin D synthase-enhanced green fluorescent protein coexpressing cells increased significantly at 5-7 days after reperfusion. Our results indicate that hematopoietic prostaglandin D synthase is mainly produced by endogenous microglia until 72 h after reperfusion, but at 7 days after reperfusion, it is also produced by migrating bone marrow/blood-derived macrophages in the ischemic brain tissue. We speculate that hematopoietic prostaglandin D synthase in the brain has different functions during early and late phases of ischemia.

Right-to-left shunt and lacunar stroke in patients without hypertension and diabetes

We analyzed the frequency of cardiac embolic sources in 62 patients with acute lacunar stroke vs 50 controls. In post hoc analysis, 11 patients with lacunar stroke having neither hypertension nor diabetes mellitus (non-HDM group) had a higher frequency of right-to-left shunt (RLS) (82%) than patients with risk factors for lacunar stroke. RLS was also independently associated with the non-HDM group. Thus, RLS may contribute to lacunar stroke in patients without risk factors for lacunar stroke.

Migration of enhanced green fluorescent protein expressing bone marrow-derived microglia/macrophage into the mouse brain following permanent focal ischemia

Brain ischemia induces a marked response of resident microglia and hematopoietic cells including monocytes/macrophages. The present study was designed to assess the distribution of microglia/macrophages in cerebral ischemia using bone marrow chimera mice known to express enhanced green fluorescent protein (EGFP). At 24 h after middle cerebral artery occlusion (MCAO), many round-shaped EGFP-positive cells migrated to the ischemic core and peri-infarct area. At 48-72 h after MCAO, irregular round- or oval-shaped EGFP/ionized calcium-binding adapter molecule 1 (Iba 1)-positive cells increased in the transition zone, while many amoeboid-shaped or large-cell-body EGFP/Iba 1-positive cells were increased in number in the innermost area of ischemia. At 7 days after MCAO, many process-bearing ramified shaped EGFP/Iba 1-positive cells were detected in the transition to the peri-infarct area, while phagocytic cells were distributed in the transition to the core area of the infarction. The distribution of these morphologically variable EGFP/Iba 1-positive cells was similar up to 14 days from MCAO. The present study directly showed the migration and distribution of bone marrow-derived monocytes/macrophages and the relationship between resident microglia and infiltrated hematogenous element in ischemic mouse brain. It is important to study the distribution of intrinsic and extrinsic microglia/macrophage in ischemic brain, since such findings may allow the design of appropriate gene-delivery system using exogenous microglia/macrophages to the ischemic brain area.

Feasibility of ex vivo gene therapy for neurological disorders using the new retroviral vector GCDNsap packaged in the vesicular stomatitis virus G protein

Neuronal progenitor cells (NPC) are particularly suited as the target population for genetic and cellular therapy of neurological disorders such as Parkinson's disease or stroke. However, genetic modification of these cells using retroviral vectors remains a great challenge because of the low transduction rate and the need for fetal calf serum (FCS) during the transduction process that induces the cell differentiation to mature neurons. To overcome these problems, we developed a new retrovirus production system in which the simplified retroviral vector GCDNsap engineered to be resistant to denovo methylation was packaged in the vesicular stomatitis virus G protein (VSV-G), concentrated by centrifugation, and resuspended in serum-free medium (StemPro-34 SFM). In transduction experiments using enhanced green fluorescent protein (EGFP) as a marker, the concentrated FCS-free virus supernatant infected NPC at a high rate, while maintaining the ability of these cells to self-renew and differentiate in vitro. When such cells were grafted into mouse brains, EGFP-expressing NPC were detected in the region around the injection site at 8 weeks post transplantation. These findings suggest that the gene transfer system described here may provide a useful tool to genetically modify NPC for treatments of neurological disorders.

Effects of gradual bone lengthening on the rabbit tibial nerve

Little is known about the effect of gradual bone lengthening on peripheral nerves. In the present study, an external fixation device was applied to the rabbit tibia, which was then divided. After seven days, the tibia was subjected to 0.7 mm/day callus distraction for periods of up to one month. The tibial nerve was fixed in glutaraldehyde and plastic sections were cut in longitudinal and transverse planes for light and electron microscopy. Light microscopy showed a 64% increase in the gap length at the node of Ranvier in myelinated axons from the experimental side compared with the control side. The cross-sectional area of the non-myelinated axons was not altered significantly. We conclude that gradual stretching of the nerve elongates the nerve fibres at least at the region of the nodes, perhaps a point of least resistance. Diameters of fibres seem to be held more constant during the lengthening procedure.

An AAV-derived Apaf-1 dominant negative inhibitor prevents MPTP toxicity as antiapoptotic gene therapy for Parkinson's disease

Adeno-associated virus (AAV) vector delivery of an Apaf-1-dominant negative inhibitor was tested for its antiapoptotic effect on degenerating nigrostriatal neurons in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of Parkinson's disease. The wild-type caspase recruitment domain of Apaf-1 was used as a dominant negative inhibitor of Apaf-1 (rAAV-Apaf-1-DN-EGFP). An AAV virus vector was used to deliver it into the striatum of C57 black mice, and the animals were treated with MPTP. The number of tyrosine hydroxylase-positive neurons in the substantia nigra was not changed on the rAAV-Apaf-1-DN-EGFP injected side compared with the noninjected side. We also examined the effect of a caspase 1 C285G mutant as a dominant negative inhibitor of caspase 1 (rAAV-caspase-1-DN-EGFP) in the same model. However, there was no difference in the number of tyrosine hydroxylase-positive neurons between the rAAV-caspase-1-DN-EGFP injected side and the noninjected side. These results indicate that delivery of Apaf-1-DN by using an AAV vector system can prevent nigrostriatal degeneration in MPTP mice, suggesting that it could be a promising therapeutic strategy for patients with Parkinson's disease. The major mechanism of dopaminergic neuronal death triggered by MPTP seems to be the mitochondrial apoptotic pathway.

Polymorphism of the lipoprotein lipase gene and risk of atherothrombotic cerebral infarction in the Japanese

BACKGROUND AND PURPOSE

Lipid and lipoprotein abnormalities have been implicated in the pathogenesis of ischemic cerebrovascular disease and atherosclerosis. Lipoprotein lipase (LPL) plays an important role in plasma lipoprotein metabolism. Several studies have recently reported the presence of a relationship between Ser447Stop mutation of LPL and coronary artery disease. Other polymorphisms (HindIII and PvuII) of the LPL gene have already been shown to correlate significantly with dyslipidemia. We investigated whether these polymorphisms are associated with increased risk of ischemic cerebrovascular disease (CVD).

METHODS

We recruited 177 CVD patients (atherothrombotic infarction, n=71; cardioembolic infarction, n=30; lacunar infarction, n=76) and 177 healthy control subjects. Subjects were genotyped for the Ser447Stop mutation and for HindIII/PvuII restriction fragment length polymorphisms of the LPL gene, and the findings were investigated for associations with the clinical subtypes of CVD and with lipid levels.

RESULTS

The Ser447Stop mutation correlated significantly with CVD (0.107 versus 0.158; P=0.035). For the CG+GG versus CC genotype, the odds ratio between control subjects and CVD patients with atherothrombotic infarction was 0.42 (95% CI, 0.18 to 0.99) (P=0.046). Serum HDL cholesterol and triglyceride levels did not correlate significantly with the Ser447Stop genotype. HindIII polymorphism correlated significantly with CVD (0.234 versus 0.169; P=0.031), but the frequency of PvuII polymorphism was not significantly different between groups.

CONCLUSIONS

Our results suggest that the Ser447Stop mutation of the LPL gene is a novel genetic marker for low risk of atherothrombotic cerebral infarction.

Accumulation of 4-hydroxynonenal-modified proteins in hippocampal CA1 pyramidal neurons precedes delayed neuronal damage in the gerbil brain

It has been proposed that reactive oxygen species and lipid peroxidation have a role in the delayed neuronal death of pyramidal cells in the CA1 region. To explore the in situ localization and serial changes of 4-hydroxy-2-nonenal-modified proteins, which are major products of membrane peroxidation, we used immunohistochemistry of the gerbil hippocampus after transient forebrain ischemia with or without preconditioning ischemia. The normal gerbil hippocampus showed weak immunoreactivity for 4-hydroxy-2-nonenal-modified proteins in the cytoplasm of CA1 pyramidal cells. 4-hydroxy-2-nonenal immunoreactivity showed no marked changes after preconditioning ischemia. In the early period after ischemia and reperfusion, there was a transient increase of nuclear 4-hydroxy-2-nonenal immunoreactivity in CA1 pyramidal neurons. In contrast, cytoplasmic immunoreactivity transiently disappeared during same period and then increased markedly from 8h to seven days. One week after ischemia, 4-hydroxy-2-nonenal immunoreactivity was observed within reactive astrocytes in the CA1 region. Early nuclear accumulation of 4-hydroxy-2-nonenal in CA1 neurons may indicate a possible role in signal transduction between the nucleus and cytoplasm/mitochondria, while delayed accumulation of 4-hydroxy-2-nonenal-modified proteins in the cytoplasm may be related to mitochondrial damage. We conclude that 4-hydroxy-2-nonenal may be a key mediator of the oxidative stress-induced neuronal signaling pathway and may have an important role in modifying delayed neuronal death.

Importance of achieving complete necrosis during the first treatment for hepatocellular carcinoma to prevent bone metastasis: a prospective study

BACKGROUND AND AIMS

Recent advances in the treatment of hepatocellular carcinoma (HCC) have changed the importance of bone metastasis during the follow up of such patients. In the present study, we investigated risk factors for bone metastasis after treatment for HCC.

METHODS

Two hundred and two patients with HCC were diagnosed as free of bone metastasis by technecium 99m-methylene diphosphonate bone scintigraphy and were followed prospectively after treatment of the primary lesions (follow-up period 2-146 months; median 20 months). We statistically analyzed the risk factors for bone metastasis using the clinical characteristics at the time of first treatment.

RESULTS

Multiple tumors (P < 0.005), main tumor size > 5 cm in diameter (P < 0.005), the presence of distant metastasis (P < 0.005), elevation of serum alpha-fetoprotein (> 100 ng/mL; P < 0.05), chemotherapy (P < 0.05) and insufficient therapeutic response (P < 0.0005) were identified as risk factors for bone metastasis by univariate analyses. Insufficient therapeutic response and main tumor size > 5 cm in diameter (both P < 0.05) were identified as independent predisposing factors for bone metastasis.

CONCLUSIONS

Complete necrosis of primary HCC during the first treatment is important to prevent subsequent bone metastasis.

Adenomyomatosis of the papilla of Vater: a case illustrating diagnostic difficulties

AIMS

To describe the extremely rare case of an adenomyoma of the papilla of Vater.

CASE REPORT

A 42-year-old woman was hospitalized for epigastralgia and high fever. The clinical presentation and endoscopic, biochemical, and radiologic findings led to the diagnostic impression of a dysfunction of the papilla of Vater. The patient was treated successfully by laparotomy and duodenotomy, incorporating cholangiomanometry and cholangiography. Intraoperative frozen-section examination of a transduodenal papillectomy specimen led to the diagnosis of adenomyomatosis of the papilla. The patient is doing well 38 months postoperatively.

CONCLUSION

Such a combined approach to intraoperative diagnosis was important to avoid excessive surgery for a benign periampullary disease.

Determination of medullasin levels for the diagnosis of multiple sclerosis

OBJECTIVES

To obtain a simple and reliable clinical parameter for the diagnosis of multiple sclerosis among patients with neurological diseases.

PATIENTS AND METHODS

Heparinized peripheral blood was obtained from patients with multiple sclerosis and those with non-inflammatory neurological diseases and healthy volunteers. A new enzyme immunoassay method determining medullasin levels in human granulocytes was developed by using mouse monoclonal antibody against medullasin.

RESULTS

A newly developed enzyme immunoassay method for medullasin can detect as little as 1 ng/ml medullasin and results can be obtained within 2 h. Eighty-five out of 112 patients with multiple sclerosis (75.8%) showed positive results (above means of normals + 2 SD) in the medullasin test, while 15.4% (12/78) of patients with non-inflammatory neurological disease had positive results.

CONCLUSION

This newly developed enzyme immunoassay method for medullasin is considered to be a useful paraclinical test for the diagnosis of multiple sclerosis.

Asymmetric cortico-cortical inhibition in patients with progressive limb-kinetic apraxia

OBJECTIVES

To evaluate the activity of cortico-cortical (intracortical) inhibitory circuits within the motor cortex in patients with progressive asymmetric limb-kinetic apraxia.

MATERIALS AND METHODS

We studied 4 patients with progressive limb-kinetic apraxia whose clinical diagnosis was corticobasal degeneration (CBD) and 7 control subjects. Cortico-cortical inhibition was measured using the technique of double pulse transcranial magnetic stimulation over the motor cortex. The effects of conditioning stimuli on the test responses were examined.

RESULTS

In the normal control subjects, the conditioning magnetic stimulus suppressed motor evoked responses to the test stimulus at interstimulus intervals of 1 to 5 ms. This inhibition was significantly diminished on the affected side of the patients, but it was normal on the less affected side.

CONCLUSION

Disruption of intracortical inhibitory circuits in the motor cortex may, at least in part, be related to severe limb clumsiness in the patients with progressive limb-kinetic apraxia.