Dexmedetomidine Inhibits Hippocampal Neuronal Damage Caused by Persistent Isoflurane-Induced Hypotension in Rat Model of Chronic Cerebral Hypoperfusion.

Purpose The purpose of this study was to investigate the effect of dexmedetomidine (DEX) on hypotension-induced neuronal damage in a chronic cerebral hypoperfusion (CCH) model of rats, an established model of cerebral white matter lesions (WML) in humans, which is prevalent in the elderly and closely related to cognitive decline. Methods The CCH model rats were randomly assigned to one of four groups: normotension + no DEX (NN) group (n = 6), normotension + DEX (ND) group (n = 6), hypotension + no DEX (HN) group (n = 6), or hypotension + DEX (HD) group (n = 6). Under isoflurane anesthesia, mean arterial blood pressure was maintained at or above 80 mmHg (normotension) or below 60 mmHg (hypotension) for a duration of two hours. The DEX groups received 50 µg of DEX intraperitoneally. Two weeks later, the Y-maze test and, after preparing brain slices, immunohistochemical staining were performed using antibodies against neuronal nuclei (NeuN), microtubule-associated protein 2 (MAP2), glial fibrillary acidic protein (GFAP), and Ionized calcium-binding adapter molecule 1 (Iba1). Results Behavioral observations showed no significant differences among the groups. Significant reductions of both NeuN-positive cells and the MAP2-positive area were found in the hippocampal CA1 in the HN group compared with NN and ND groups, but not in the HD group. GFAP and Iba-1-positive areas were significantly increased in the HN group, but not in the HD group. Conclusion DEX significantly ameliorated hypotension-induced neuronal damage and both astroglial and microglial activation in the CA1 region of CCH rats.

Annotated checklist of ponyfishes (Perciformes: Leiognathidae) from Bangladesh, the northern Bay of Bengal.

Information on the taxonomy of ponyfishes (Leiognathidae Gill 1893) from Bangladesh was hitherto inadequate and details of some species were lacking. Based on specimens, the present study reports 12 species of ponyfishes from the coasts of Bangladesh with short descriptions of their diagnostic characters. Six of these species, Aurigequula longispina (Valenciennes 1835), Deveximentum megalolepis (Mochizuki & Hayashi 1989), Equulites leuciscus (Günther 1860), Eubleekeria rapsoni (Munro 1964), Gazza rhombea Kimura, Yamashita & Iwatsuki 2000 and Karalla daura (Cuvier 1829), constitute the first records in Bangladesh. The present specimens of D. megalolepis represent the westernmost distribution of this species in the Indo-Pacific region.

Propofol suppresses the His-ventricular conduction in paediatric patients.

WHAT IS KNOWN AND OBJECTIVE: Propofol is the most commonly used intravenous anaesthetic worldwide and is considered to be safe for all ages. However, there have been some reports that propofol induces severe atrioventricular (AV) blocks in humans and some studies demonstrated that propofol suppressed the cardiac conduction system in animals. A precise mechanism by which the block is induced has not been elucidated yet in humans. The objective of this study was to investigate the effects of propofol on the cardiac conduction system and the cardiac autonomic nervous balance in children. METHODS: We enrolled 23 paediatric patients (age: 6-15 years; males: 16, females: 7) who were scheduled to undergo radiofrequency catheter ablation (RFCA) under general anaesthesia. Anaesthesia was induced with 2 mg/kg propofol and 0.5 µg/kg/min remifentanil, and tracheal intubation was performed with the aid of 1 mg/kg rocuronium. Anaesthesia was maintained with 5-7 mg/kg/h propofol and 0.2 µg/kg/min remifentanil during the RFCA. After the completion of the RFCA, anaesthesia was further maintained with 5 mg/kg/h propofol and 0.2 µg/kg/min remifentanil for at least 10 min (LC: low propofol concentration state), followed by the injection of 2 mg/kg propofol and the infusion of 10 mg/kg/h propofol for 10 min (HC: high propofol concentration state). The sinus node recovery time (SNRT), sinoatrial conduction time (SACT), atrial-His (AH) interval and the His-ventricular (HV) interval were measured at the end of both the LC and HC. Cardiac autonomic regulation was simultaneously assessed based on heart rate variability. RESULTS AND DISCUSSION: Propofol significantly suppressed intrinsic cardiac HV conduction, but did not affect the SNRT, SACT or the AH interval. As HV blocks, which occur below the His bundle, are often life-threatening, the HV conduction delay may be a cause of severe AV blocks induced by propofol. Propofol directly suppressed parasympathetic nerve activity, and sympathetic nerve activity was also suppressed. WHAT IS NEW AND CONCLUSION: These results indicate that propofol suppresses the HV conduction and might help to elucidate the mechanism by which propofol causes lethal AV blocks.

Can left ventricular hypertrophy on electrocardiography detect severe aortic valve stenosis?

BACKGROUND: Severe aortic stenosis (AS) is increasing in the aging society and is a serious condition for anesthetic management. However, approximately one-third of patients with severe AS are asymptomatic. Echocardiography is the most reliable method to detect AS, but it takes time and is costly. METHODS: Data were obtained retrospectively from patients who underwent surgery and preoperative transthoracic echocardiography (TTE). LVH on ECG was determined by voltage criteria (Sv1 + Rv5 or 6 ≥3.5 mV) and/or the strain pattern in V5 and V6. Severe AS was defined as a mean transaortic pressure gradient ≥40 mmHg or aortic valve area ≤1.0 cm2 by TTE. RESULTS: Data for 470 patients aged 28-94 years old were obtained. One hundred and twenty-six patients had severe AS. LVH on ECG by voltage criteria alone was detected in 182 patients, LVH by strain pattern alone was detected in 80 patients and LVH by both was detected in 55 patients. Multivariable logistic analysis revealed that LVH by the strain pattern or voltage criteria, diabetes mellitus, and age were significantly associated with severe AS. The AUC for the ROC curve for LVH by voltage criteria alone was 0.675 and the cut-off value was 3.84 mm V, and the AUC for the ROC for age was 0.675 and the cut-off value was 74 years old. CONCLUSION: Our study suggests that patients who are 74 years old or over with LVH on ECG, especially those with DM, should undergo preoperative TTE in order to detect severe AS.

Brain white matter lesions and postoperative cognitive dysfunction: a review.

Postoperative cognitive dysfunction (POCD) is a serious complication of anesthesia and surgery, and the major risk factor of POCD is aging. Although the exact pathophysiology of POCD remains unknown, two possible and reliable mechanisms have been proposed: neuroinflammation and neurodegeneration, i.e., amyloid ß accumulation and/or tau protein phosphorylation, by surgery and/or general anesthetics. White matter lesions (WML) are produced by chronic cerebral hypoperfusion, frequently observed in elderly people, and closely related to cognitive decline. As recent studies have revealed that WML are a significant risk factor for POCD in humans, and we previously also demonstrated that persistent hypocapnea or hypotension caused neuronal damage in the caudoputamen or the hippocampus in a rat model of chronic cerebral hypoperfusion, which features global cerebral WML without neuronal damage and is recognized as a good model of human vascular dementia especially in elderly people, we hypothesize that in addition to those two previously proposed mechanisms, perioperative vital sign changes that cause reductions in cerebral blood flow might contribute to POCD in patients with WML, whose cerebral blood flow is already considerably decreased.

Persistent isoflurane-induced hypotension causes hippocampal neuronal damage in a rat model of chronic cerebral hypoperfusion.

BACKGROUND: Postoperative cognitive dysfunction (POCD) is likely to occur in elderly people, who often suffer from cerebral hypoperfusion and white matter lesions even in the absence of cerebral infarctions. METHODS: Thirty-two adult male rats were randomly assigned to one of four groups: the cerebral normoperfusion + normotension group (n = 8), cerebral normoperfusion + hypotension group (n = 8), chronic cerebral hypoperfusion (CCH) + normotension group (n = 8), and CCH + hypotension group (n = 8). A rat model of CCH was developed via the permanent ligation of the bilateral common carotid arteries, but ligation was avoided in the cerebral normoperfusion groups. Two weeks later, the rats were intubated and mechanically ventilated under isoflurane anesthesia, and their mean arterial blood pressure was maintained over 80 mmHg (normotension) or below 60 mmHg (hypotension) for 2 h. After preparing brain slices, histological cresyl violet staining, ionized calcium binding adaptor molecule 1, a marker of microglial activation, or ß amyloid precursor protein, a marker of axonal damage, were performed. RESULTS AND CONCLUSION: CCH per se caused microglial activation and axonal damage, which was not accentuated by hypotension. CCH alone did not cause neuronal damage, but CCH combined with hypotension caused significant neuronal damage in the hippocampal CA1 region. These results suggest that persistent hypotension during general anesthesia might cause neuronal damage in patients with CCH, such as elderly people, and contribute to prevention against POCD.

Sevoflurane causes greater QTc interval prolongation in chronically hyperglycemic patients than in normoglycemic patients.

QTc interval prolongation is a serious diabetic complication and increases mortality rate. Hyperglycemia inhibits the rapid component of delayed rectifier potassium channel currents (Ikr) and prolongs the QTc interval on electrocardiograms. Sevoflurane also inhibits the Ikr and causes QTc interval prolongation. In fact, torsade de pointes occurred in a patient with poorly controlled diabetes mellitus during sevoflurane anesthesia. We enrolled 74 patients, including 37 normoglycemic patients (glycated hemoglobin [HbA1c]: <6.5%) (NG group) and 37 chronically hyperglycemic patients (HbA1c: ≥6.5%) (HG group). Anesthesia was induced with 2 mg/kg propofol and 0.3 µg/kg/min remifentanil, and maintained with 2% sevoflurane in 40% O2 and 0.2-0.3 µg/kg/min remifentanil. The QT interval and Tp-e interval (from the peak to the end of the T wave) were measured before and at 5, 10, 30, 60, 90, and 120 min after the administration of sevoflurane and adjusted for the patient's heart rate (QTc and Tp-ec, respectively). P-values of <0.05 were considered statistically significant. The QTc and the Tp-ec intervals of the two groups did not differ significantly before the administration of sevoflurane. The QTc interval gradually increased with time in both groups and was significantly longer than the baseline value at 10 min after the administration of sevoflurane in both groups. The QTc interval of the HG group was significantly longer than that of the NG group at 90 min and 120 min after the administration of sevoflurane. The Tp-ec interval was not affected by sevoflurane in either group.We have demonstrated that sevoflurane significantly prolongs the QTc interval, and that the extent of the prolongation is significantly greater in chronically hyperglycemic patients than in normoglycemic patients. Although Tp-ec is not affected by sevoflurane, it should be noted that the simultaneous blockade of potassium channels would increase the risk of arrhythmias.

A new genus and species of the family Symphysanodontidae, Cymatognathus aureolateralis (Actinopterygii: Perciformes) from Indonesia.

A new genus and species of the percoid family Symphysanodontidae, Cymatognathus aureolateralis are described based on three specimens collected from North Sulawesi, Indonesia. The new species shares with the confamilial genus Sym-physanodon the unique supraneural and spinous dorsal-fin pterygiophore insertion pattern usually of 0/0/0+2+1/1/, T-shaped first supraneural, foreshortened base of the penultimate ventral procurrent caudal-fin ray, well-developed outer tooth patches at anterior tips of both jaws as well as along the medial surface of most of the length of the coronoid process of the dentary. The new species, however, is distinguishable from members of Symphysanodon by the following diagnostic characters: posterior tip of coronoid process of dentary abruptly depressed, so that teeth on anterior portion appear as an elevated patch, anterior tip of upper jaw not notched, and posterior nostril horizontally slit-like. Although the new species superficially resembles the members of the genus Giganthias (Giganthiidae) and some members of the subfamily Anthiadinae (Serranidae) in the unique characters it shares with Symphysanodon, it differs from Giganthias in having the above-mentioned unique pterygiophore insertion pattern and tips of all dorsal- and pelvic-fin spines smooth (vs. pterygiophore insertion pattern 0/0/2/1+1/1/, and tips of second, third and/or fourth dorsal- and pelvic-fin spines serrated), and from the members of Anthiadinae in having two flat opercular spines (vs. three) and 10 + 15 = 25 vertebrae (vs. 10 + 16-18 = 26-28). A revised diagnosis of the Symphysanodontidae is presented.

Sevoflurane prolonged the QTc interval and increased transmural dispersion of repolarization in a patient with long QT syndrome 3: a case report.

We report that sevoflurane not only caused marked QTc interval prolongation but also increased transmural dispersion of repolarization in a patient with long QT syndrome 3 (LQT3). A 16-year-old male with LQT3 underwent a shoulder operation. He experienced no episode of syncope or cardiac arrest, but his preoperative electrocardiography (ECG) showed marked QTc interval prolongation (631 ms) and Tp-e interval prolongation (126 ms). Anesthesia was induced with propofol and maintained with 2% sevoflurane and remifentanil. Although no lethal arrhythmias occurred in the perioperative period, not only the QTc interval but also Tp-e interval was further prolonged by sevoflurane. While sevoflurane has been recognized as a safe anesthetic in terms of QT interval prolongation, even in patients with long QT syndromes, we believe that sevoflurane might be avoided for poorly controlled LQT3 patients.

A new species of Apterichtus (Anguilliformes: Ophichthidae) from the Marquesas Islands.

A new finless ophichthid eel, Apterichtus succinus sp. nov., is described based on a single specimen collected from the Marquesas Islands. The new species closely resembles A. klazingai Weber, 1913 in the shape and coloration of its head and its total vertebral count. The former differs from the latter in having more preopercular pores (4 vs. 3), fewer preanal vertebrae (54 vs. 56-63), a single tooth on the prevomer (generally absent), a shorter head (14.8 in TL vs. 12-14 in TL), and larger spots on its head and nape. Three species of Apterichtus (A. succinus, A. klazingai, and Apterichtus mysi McCosker & Hibino, 2015) are recognized from the Marquesas Islands.

A new genus and species of worm eels, Sympenchelys taiwanensis (Anguilliformes: Ophichthidae: Myrophinae), from the northwestern Pacific Ocean.

A new genus and species of ophichthid eel, Sympenchelys taiwanensis is described. The genus is distinguishable from all other myrophine genera by having neural and haemal spines with well-developed paddle-like tips, and from two closely similar genera, Mureaenichthys Bleeker 1853 and Skythrenchelys Castle & McCosker 1999, by the following combination of characters: an unconstricted gill opening; a minute flap just posterior to the gill opening; a slender cleithrum; three preopercular pores; a slender and distinctly tapered maxilla; an undeveloped supraoccipital crest; and large and recurved teeth on jaws and vomer. Sympenchelys taiwanensis is described from five specimens collected from Taiwan, the northwestern Pacific Ocean.

A new species of Neenchelys (Anguilliformes: Ophichthidae: Myrophinae) from the eastern Indian Ocean.

A new worm eel, Neenchelys andamanensis, is described based on a single specimen collected from a depth of 520-531 m, Andaman Sea, eastern Indian Ocean. The new species is similar to N. daedalus, N. nudiceps, and N. similis in its total vertebral count and slender body, however, it differs from the latter three in having a shorter tail (60% TL vs. 70-76%), more numerous preanal vertebrae (77 vs. 59-71), and shorter pectoral fins (2.4% HL vs. 21-27%). Although the new species resembles N. mccoskeri in some proportional characters, the former species is distinguishable from the latter by its higher total vertebral count (221 vs. 172-184), position of the dorsal-fin origin (horizontal distance from the origin to a vertical through mid-anus 65% of trunk length vs. 46-59%) and width of the interorbital region (4.5% of head length vs. 8.2-16%). A revised key to the species of Neenchelys is provided.

A new species of Muraenichthys (Anguilliformes: Ophichthidae) from the Indo-Pacific, with revised generic diagnosis.

A new worm eel (Ophichthidae, Myrophinae), Muraenichthys velinasalis, is described based on five specimens (97.9-281.0 mm of total length) collected from Taiwan, Philippines, northeastern Australia, Vanuatu, and Sri Lanka. Muranichthys velinasalis is most similar to M. philippinensis and M. schultzei in the position of the dorsal-fin origin behind a vertical through mid-anus, but can be easily distinguished from the latter two species by the condition of the posterior nostril, unique character of M. velinasalis within Muraenichthys, and by the shape of the teeth on the innermost row of the upper jaw (relatively robust and slightly pointed vs. slender and pointed), arrangement of upper-jaw teeth (irregularly biserial anteriorly and uniserial posteriorly vs. completely uniserial in M. philippinensis, biserial or triserial in M. schultzei), and its more numerous or fewer preanal and total vertebrae (44-51 vs. 59-60 in M. philippinensis, 42-47 in M. schultzei; 136-139 vs. 128-130 in M. philippinensis, 119-128 in M. schultzei). The genus Muraenichthys is re-defined based on all currently valid species by the following combination of characters: eyes located anterior to mid-jaw; inner hole of posterior nostril above upper lip, and outer hole usually outside of mouth, with a prominent but short projected flap anteriorly; a single pore between anterior and posterior nostrils; three preopercular pores; teeth on jaws, vomer, and intermaxillary area; tooth shape variable, blunt to pointed but not distinctly recurved and tooth length equal or less than a half of eye diameter; teeth on jaws and vomer arranged in one to five rows; gill opening constricted, its height<170% of eye diameter; pectoral fins absent.

[A patient with advanced breast cancer who developed bacterial meningitis after chemotherapy].

A 76-year-old woman was admitted to our hospital because of a right breast tumor and a skin ulcer. The patient was diagnosed as having advanced breast cancer T4bN2M1(lung), Stage IV. A regimen of 5-fluorouracil(500mg/m2)with epirubicin(100mg/m / 2)and cyclophosphamide(500mg/m2)(FEC100)was administered. However, the patient was hospitalized 12 days later because of febrile neutropenia. The patient experienced a stiff neck the next day, and bacterial meningitis was diagnosed on the basis of cerebrospinal fluid examination. Antibacterial agents were administered according to the clinical practice guidelines of bacterial meningitis. The patient recovered and was discharged from our hospital 24 days after admission. Bacterial meningitis after chemotherapy is rare, but this could be progress to a serious condition. Early diagnosis and treatment are paramount in such cases.

Expression of HDAC1 and CBP/p300 in human colorectal carcinomas.

BACKGROUND: The histone-modifying enzymes histone deacetylase (HDAC) and histone acetyltransferase (HAT) control gene transcriptional activation and repression in human malignancies. AIMS: To analyse the expression of HDAC/HAT-associated molecules such as HDAC1, CREB-binding protein (CBP) and p300 in human colorectal carcinomas, and investigate the relationship between their expression levels and clinicopathological parameters. METHODS: Expression levels of HDAC1, CBP, and p300 in human colorectal cancer were investigated by immunohistochemistry. In situ hybridisation (ISH) and reverse transcription (RT)-PCR analyses were also carried out to confirm mRNA expression levels of these genes. Immunoreactivity was evaluated semi-quantitatively using a staining index (SI). The relationships between the SIs and clinicopathological findings were analysed and survival curves were calculated using the Kaplan-Meier method and log-rank tests. RESULTS: The mean SIs for HDAC1, CBP, and p300 in this series of tumours were much higher than those in normal colonic mucosa. The presence of HDAC1 and CBP mRNAs on colorectal carcinoma cells as well as normal epithelial cells was confirmed by ISH analysis. A marked increase in p300 mRNA levels was detected in a majority of cases by RT-PCR. Among the patients with colorectal cancer, overexpression of p300 (SI>11.9) correlated with a poor prognosis, whereas high CBP expression levels (SI>16.6) indicated long-term survival. CONCLUSION: Results showed the up-regulation of these three histone-modifying molecules in this series of colorectal cancers and suggested that monitoring of CBP and p300 may assist prediction of the prognosis in patients with colorectal adenocarcinoma.

Phylogenetic relationships and natural hybridization in rabbitfishes (Teleostei: Siganidae) inferred from mitochondrial and nuclear DNA analyses.

Phylogenetic relationships of rabbitfishes (the family Siganidae), ecologically important components as primary consumers in coral reef communities, were studied using mitochondrial cytochrome b gene and nuclear ITS1 (internal transcribed spacer 1) sequence analyses. The analyses of 19 out of 22 species known in the Western Pacific region revealed that siganids are genetically clustered into three major clades, which are characterized by some morphological and ecological traits. Between closely related species, such as Siganus guttatus-S. lineatus and S. virgatus-S. doliatus, and also between two morphs recognized in S. corallinus, small but discernible genetic differentiation was found, implying that the components of each pair are incipient species. On the other hand, between some species, such as S. fuscescens-S. canaliculatus and S. unimaculatus-S.vulpinus, individuals of the components of each pair were found to construct a genetic mosaic, suggesting that the components are genetic color morphs within a single biological species, respectively. Moreover, evidence from morphological characters, mtDNA, and nuclear DNA gave an inconsistent picture of identity and relationships for several individuals. They were regarded as hybrids or individuals with hybrid origin. Such instances were observed not only between closely related species, such as S. guttatus-S. lineatus, S. virgatus-S. doliatus, and two morphs (incipient species) in S. corallinus, respectively, but also between distantly related ones, such as S. corallinus-S. puellus. In fact, more than half of the species examined (11/20, when treating the two morphs in S. corallinus as independent species) were involved in hybridization. These suggest that hybridization is much more prevalent in marine fishes than previously assumed, and may have some relevance to their diversification.

Phylogenetic diversity and cosymbiosis in the bioluminescent symbioses of "Photobacterium mandapamensis".

"Photobacterium mandapamensis" (proposed name) and Photobacterium leiognathi are closely related, phenotypically similar marine bacteria that form bioluminescent symbioses with marine animals. Despite their similarity, however, these bacteria can be distinguished phylogenetically by sequence divergence of their luminescence genes, luxCDAB(F)E, by the presence (P. mandapamensis) or the absence (P. leiognathi) of luxF and, as shown here, by the sequence divergence of genes involved in the synthesis of riboflavin, ribBHA. To gain insight into the possibility that P. mandapamensis and P. leiognathi are ecologically distinct, we used these phylogenetic criteria to determine the incidence of P. mandapamensis as a bioluminescent symbiont of marine animals. Five fish species, Acropoma japonicum (Perciformes, Acropomatidae), Photopectoralis panayensis and Photopectoralis bindus (Perciformes, Leiognathidae), Siphamia versicolor (Perciformes, Apogonidae), and Gadella jordani (Gadiformes, Moridae), were found to harbor P. mandapamensis in their light organs. Specimens of A. japonicus, P. panayensis, and P. bindus harbored P. mandapamensis and P. leiognathi together as cosymbionts of the same light organ. Regardless of cosymbiosis, P. mandapamensis was the predominant symbiont of A. japonicum, and it was the apparently exclusive symbiont of S. versicolor and G. jordani. In contrast, P. leiognathi was found to be the predominant symbiont of P. panayensis and P. bindus, and it appears to be the exclusive symbiont of other leiognathid fishes and a loliginid squid. A phylogenetic test for cospeciation revealed no evidence of codivergence between P. mandapamensis and its host fishes, indicating that coevolution apparently is not the basis for this bacterium's host preferences. These results, which are the first report of bacterial cosymbiosis in fish light organs and the first demonstration that P. leiognathi is not the exclusive light organ symbiont of leiognathid fishes, demonstrate that the host species ranges of P. mandapamensis and P. leiognathi are substantially distinct. The host range difference underscores possible differences in the environmental distributions and physiologies of these two bacterial species.