Sialorphin Potentiates Effects of [Met5]Enkephalin without Toxicity by Action other than Peptidase Inhibition.

This dose-response study investigated the effects of sialorphin on [Met5]enkephalin (ME)-induced inhibition of contractions in mouse vas deferens and antinociception in male rats. Differences were compared among combinations of three chemical peptidase inhibitors: amastatin, captopril, and phosphoramidon. The ratio of potencies of ME in mouse vas deferens pretreated with both sialorphin (100 µM) and a mixture of the three peptidase inhibitors (1 µM each) was higher than that with the mixture of peptidase inhibitors alone at any dose. Intrathecal administration of sialorphin (100-400 nmol) significantly and dose dependently increased ME (3 nmol)-induced antinociception with the mixture of three peptidase inhibitors (10 nmol each). The degree of antinociception with a combination of any two of the peptidase inhibitors (10 nmol each) in the absence of sialorphin was less than that in the presence of sialorphin (200 nmol). Pretreatment with both sialorphin (200 nmol) and the mixture of three peptidase inhibitors (10 nmol each) produced an approximately 100-fold augmentation in ME (10 nmol)-induced antinociception, but without signs of toxicity such as motor dysfunction in rats. Radioligand receptor binding assay revealed that sialorphin did not affect either binding affinity or maximal binding capacity of [d-Ala2,N-MePhe4,Gly-ol5]enkephalin. These results indicate that sialorphin potentiates the effects of ME without toxicity by a mechanism other than peptidase inhibition and with no effect on its affinity to µ-opioid receptors. SIGNIFICANCE STATEMENT: Sialorphin is regarded as an endogenous peptidase inhibitor that interacts with enkephalin-degrading enzymes. The results of these in vitro and in vivo studies confirm that sialorphin potentiates the effects of [Met5]enkephalin without toxicity by an action other than peptidase inhibition. This suggests that sialorphin offers the advantage of reducing or negating the side effects of opioid drugs and endogenous opioid peptides.

Correlation Between Body Movements and Salivary Secretion During Sedation.

During dental sedation, control of the cough reflex is crucial for a safe and smooth procedure. Accumulated saliva is one of the predisposing factors for coughing. Body movements during dental sedation appear to enhance salivation. Therefore, the aim of this study was to investigate the difference in salivary secretion between the with-movements state and the without-movements state during sedation. Salivary weight for 1 min was measured 3 times in 27 patients with intellectual disability during dental treatment under deep sedation with midazolam and propofol. The observed variables were body movements, bispectral index (BIS), and predicted propofol effect-site concentration. A total of 81 measurements were classified into the with-movements state (n = 39; ie, measurements during which body movements were observed) or the without-movements state (n = 42; ie, measurements during which no body movements were observed). The median salivary weight was significantly smaller in the without-movements state compared with the with-movements state (0.03 vs 0.11 g, P < .0001). The BIS was significantly lower in the without-movements state. There was no significant difference in the predicted propofol effect-site concentration between the 2 states. Significant correlation was observed between salivary weight and BIS in the with-movements state (r = 0.44, P = .004). The findings indicate that salivary secretion decreased according to deep sedation. Furthermore, immobility also reduced salivary secretion. We concluded that one reason that immobility is beneficial is because of the resulting decreased salivary secretion during dental treatment under deep sedation.

Effect of three peptidase inhibitors on antinociceptive potential and toxicity with intracerebroventricular administration of dynorphin A (1-17) or (1-13) in the rat.

PURPOSE: The N- and C-terminal regions of dynorphin (Dyn) A (1-17) activate opioid and N-methyl-D-aspartate receptors, respectively. Earlier studies demonstrated that Dyn-converting enzyme cleaved Dyn A (1-17) mainly at the Arg(6)-Arg(7) bond, resulting in the production of N- and C-terminal region peptide fragments, and that this enzyme was not inhibited by a mixture of the three peptidase inhibitors (PIs) amastatin (A), captopril (C), and phosphoramidon (P). The purpose of the present study was to evaluate antinociceptive potential and toxicity with intracerebroventricular administration of Dyn A (1-17) or (1-13) under pretreatment with a mixture of A, C, and P and/or Dyn-converting enzyme inhibitor (p-hydroxymercuribenzoate). METHODS: Peptide fragments from Dyn A (1-17) following incubation with membrane preparation under pretreatment with a mixture of the three PIs was identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometer (MALDI-TOF-MS). Infusion of drugs and peptides into the third ventricle in rats was performed via indwelling cannulae. Induction of antinociception and toxicity by Dyn A (1-17), Dyn A (1-13), Dyn A (1-6), or Dyn A (7-17) were determined by the tail-flick test and induction of barrel rotation, respectively. The effects of the PIs on antinociception and toxicity were evaluated by a dose-response study and a comparison of differences among various combinations of Dyn A (1-17) or Dyn A (1-13) and the three PIs and p-hydroxymercuribenzoate. RESULTS: MALDI-TOF-MS analysis identified Dyn A (1-6) and Dyn A (1-10) fragments as products following incubation of Dyn A (1-17) with membrane preparation of rat midbrain under pretreatment with a mixture of the three PIs. Pretreatment with a mixture of the three PIs produced an approximately 30-fold augmentation in antinociception induced by low-dose intracerebroventricular administration of Dyn A (1-17) or (1-13) in a µ-, δ- and κ-opioid receptor antagonist-reversible manner, but without signs of toxicity such as barrel rotation in the rat. Dyn A (1-17)-induced antinociception and toxicity was greater than that of Dyn A (1-6), Dyn A (1-13), or Dyn A (7-17) at the same dose. Dyn A (1-17)-induced antinociception and toxicity under pretreatment with various combinations of the three PIs and p-hydroxymercuribenzoate was greater than that with a mixture of the three PIs alone. CONCLUSION: These findings suggest that administration of a mixture of the three PIs increases Dyn A (1-17)- or (1-13)-induced antinociception under physiological conditions without toxicity.

Successful Double-lumen Tube Intubation in the Lateral Position for a Patient with a Giant Superior Mediastinal Tumor.

OBJECTIVE: Anesthetic management of patients with giant mediastinal tumors is challenging from the perspective of both cardiovascular and respiratory management, and airway assessment is important for both concerns. We report the successful induction of general anesthesia and double-lumen tube intubation in the right lateral position for a patient with a giant mediastinal tumor with tracheal compression, using pre-operative chest radiograph imaging to minimize tracheal compression during induction. METHODS: A 41-year-old man required thoracoscopic giant superior mediastinal tumor resection. His trachea was compressed and displaced because of the tumor. Because preoperative chest radiography revealed that the tracheal diameter increased in the right lateral position, we chose this position for induction. RESULTS: Prompt and smooth intubation with a 35-Fr double-lumen tube (DLT) was achieved, and no adverse events associated with intubation were encountered. CONCLUSION: Safe and smooth induction with a DLT was performed owing to the perioperative chest radiograph imaging examination, which revealed the most advantageous position regarding minimal tracheal compression.

Hes1 is required for the development of craniofacial structures derived from ectomesenchymal neural crest cells.

The cranial neural crest cells contribute extensively to the formation of skeletogenic mesenchyme in the head and neck. Hes1 functions as a repressor of basic helix-loop-helix transcription factors and is implicated in controlling the maintenance of undifferentiated cells and the timing of cell differentiation. We show here that Hes1 homozygous null mutant mice exhibit multiple craniofacial malformations including calvaria agenesis, defective anterior cranial base, shortened maxilla and mandible, and abnormal palate and tongue. In the null mutant cranium, the calvarial bones, meninges including the dura mater and skin were not formed, and the brain was therefore exposed without the outer cover. The defective anterior cranial base in the mutants was attributable to the lack of presphenoid bone and the flexed cranial base angle, which was in contrast with the flat cranial base of wild-type mice. Furthermore, in the null mutants, palatal shelf growth was impaired because of the early elevation of the palatal shelves, resulting in a narrow palate and oral cavity, which were consistently associated with a small size of the tongue. These craniofacial anomalies could be the result of the defective development of neural crest cells. Taken together, it is supposed that Hes1 signaling plays an essential role in regulating the development of various craniofacial structures derived from the cranial neural crest cells.

Successful Intubation Using the Airtraq Double Lumen® with the Universal Adapter for Smartphones® in a Case of Intubation Difficulty.

OBJECTIVE: The Universal Adapter for Smartphones® c an record s till images and movies during intubation using the monitor display and recording functions of a smartphone. Here, we describe the successful use of the Airtraq Double Lumen® with the Universal Adapter for Smartphones® for airway management during anesthesia in a patient with intubation difficulty. METHODS: A 78-year-old man required thoracoscopic upper lobectomy for a pulmonary tumor. Preoperative examination revealed micrognathia, mouth opening equivalent to a three-finger width, Mallampati Class II, mentum-hyoid bone distance equal to a 2.5-finger width, hyoid bone-thyroid cartilage distance equal to a two-finger width, and Class I findings in the Upper Lip Bite Test. After inducing anesthesia and confirming the feasibility of mask ventilation, we administered 70 mg of rocuronium and inserted the Airtraq Double Lumen®. The Universal Adapter for Smartphones® connected to a 4-inch iPod Touch® was attached to its eye cup, through which the iPod Touch displayed images for easy visualization of the glottal area. RESULTS: Prompt and smooth intubation with a 35-Fr double-lumen tube (DLT) was achieved. There were no adverse events associated with intubation. CONCLUSION: Combination of the Universal Adapter for Smartphones® and the Airtraq Double Lumen® can facilitate smooth tracheal intubation with a DLT in cases of difficult intubation.

A Case of Superior Mesenteric Artery Occlusion Caused by Delayed Administration of Anticoagulants in a Patient with Nonvalvular Atrial Fibrillation.

A 86-year-old female with nonvalvular atrial fibrillation (NOVAF) who did not receive prophylactic anticoagulant treatment visited our hospital because of gastrointestinal symptoms. At first, acute gastroenteritis was suspected, but later she developed ileus and she was diagnosed with superior mesenteric artery occlusion (SMAO). We successfully performed the anesthetic management of this patient and subtotal resection of the small intestine was performed. Heparin was initiated after surgery, but she developed cerebral infarction later, and finally she died due to infection and anemia caused by melena. Although this patient was at high risk of thrombosis, she did not receive anticoagulant treatment. It might result in developing SMAO, and once SMAO occurred, thrombosis recurred even on anticoagulant treatment. This case suggested the importance of primary prevention of thrombosis in patients with NVAF.

Nicotinamide promotes long-term survival and extensive neurite outgrowth in ultimobranchial C cells cultured from chick embryos.

In avian species, the ultimobranchial anlage is populated with neuronal cells derived from the distal vagal ganglion. We found that ultimobranchial C cells of chick embryos cultured in the presence of nicotinamide continued to grow for at least 60 days and exhibited profound morphological changes, resulting in the formation of dense networks of neuronal fibers. Nicotinamide, thus, facilitated the manifestation of neuronal features in C cells. The neuronal phenotypes of cultured C cells were analyzed in detail by both scanning and transmission electron microscopy. Their neural nature was also positively established by immunostaining with monoclonal antibodies to the neuronal markers neuron-specific class III beta-tubulin (TuJ1), microtubule-associated protein (MAP) 2, and synaptophysin. Confocal laser scanning microscopy confirmed that these neuron-specific proteins are colocalized with calcitonin in both the somata and the neuronal processes of C cells. Furthermore, reverse transcriptase-polymerase chain reaction analyses, performed at various times up to 30 days in culture, indicated that the C cells have persistent gene expression of calcitonin, the catecholamine-synthesizing enzyme tyrosine hydroxylase, proenkephalin, proopiomelanocortin, neuron-specific beta-tubulin (cbeta4), SCG10, and Bcl-2. The morphological responses of C cells to nicotinamide treatment were analyzed quantitatively over a period of 60 days. The area of C-cell colonies, number of processes per colony, and length of processes continued to increase until culture day 45. In conclusion, nicotinamide stimulates long-term survival and neuronal differentiation of chick embryo C cells, and this culture system may provide a useful model for studying neuronal differentiation mechanisms.

Visibility of ultrasound-guided echogenic needle and its potential in clinical delivery of regional anesthesia.

OBJECTIVE: Ultrasound-guided regional anesthesia is recommended for nerve block due to its safety and reliability. Needle visualization is important when inserting needles into tissues in close proximity to target nerves. For safety reasons, the tip of the standard-type needle for application of nerve block is thinner than that of an interventional needle for insertion into intra-abdominal organs, and this makes it harder to determine its precise position. The purpose of this study was to evaluate the performance of an insulated echogenic needle under ultrasound guidance in phantoms and in the routine anesthetic management of patients undergoing elective surgery. METHODS: Needles with a 21-G diameter were inserted into Blue PhantomTM (Advanced Medical Technologies, LLC, WA) and chicken breast phantoms at angles of 15, 30, 45, 60, and 75 degrees relative to the surface. The needle was scanned by ultrasound using a TiTANTM (SonoSite, WA, USA). Visualization was compared between an insulated needle with corner cube reflectors (CCR-type: Hakko, Japan) and an insulated standard needle (S-type: Hakko, Japan). Both types of needle were also used to deliver regional anesthesia in patients with an ASA classification of PS1-2 undergoing elective surgery. RESULTS: The tip of CCR appeared as 3 bright points under ultrasound, and was more hyperechoic than S. The CCR-type needle was clearly visible under ultrasound at insertion angles of 15, 30, and 45 degrees, and was consistently more hyperechoic than S. However, at steeper angles of > 60 degrees, visibility was poorer. In delivering clinical regional nerve block, CCR was usually more hyperechoic than S, allowing the nerve block points targeted to be accessed with greater ease. CONCLUSIONS: The better visibility of the tip of CCR indicates that it is superior to S in the clinical delivery of peripheral nerve block.

Increase in antinociceptive effect of [leu5]enkephalin after intrathecal administration of mixture of three peptidase inhibitors.

OBJECTIVE: Previous in vitro studies have shown that the degradation of [Leu5]enkephalin during incubation with cerebral membrane preparations is almost completely prevented by a mixture of three peptidase inhibitors such as amastatin, captopril, and phosphoramidon. The present in vivo study was performed to examine the antinociceptive effect of [Leu5]enkephalin administered intrathecally under pretreatment with these three peptidase inhibitors. METHODS: A tail-flick test was used to determine the nociceptive threshold after administration of [Leu5]enkephalin. The time-course profiles of the latency to flick the tail and the area under the time response curve were evaluated for the antinociceptive action of the drug. RESULTS: The antinociceptive effect of [Leu5]enkephalin administered intrathecally on the tail-flick test was increased more than 100-fold under i.t. pretreatment with three peptidase inhibitors. The antinociceptive effect produced by [Leu5]enkephalin in rats pretreated with any single peptidase inhibitor increased antinociception compared to that with saline. The antinociceptive potency of [Leu5]enkephalin under pretreatment with any combination of two peptidase inhibitors was smaller than that in rats pretreated with three peptidase inhibitors together. These results indicate that any residual single peptidase inactivates significant amounts of [Leu5]enkephalin. CONCLUSION: The present data, together with those of earlier studies, clearly demonstrate that amastatin-, captopril-, and phosphoramidon-sensitive enzymes play an important role in the inactivation of [Leu5]enkephalin administered intrathecally in rat.

An in vitro method to measure permeability of gases through a cuff membrane of tracheal tube in conditions relevant to its clinical uses.

The cuff pressure on a tracheal tube while being used in a clinical setting is affected by various physiological conditions. Hence, it is difficult to accurately assess the tracheal tube cuff membrane permeability for gases. We developed an experimental system that enabled accurate assessment of the transition and permeability of gases through a cuff membrane. To simulate nitrous oxide anesthesia, the partial pressure about a cuff membrane was considered separately in oral side, pulmonary side, and intracuff. The cuff pressure of a newly developed tracheal tube with gas barrier materials was assessed, and the permeability through the cuff membrane was evaluated. As a result, the study condition of Experiment II (the cuff was inflated with a gas mixture of 50% nitrous oxide and 50% oxygen) was the most appropriate in which the intracuff was inflated with the same gas mixure because of no concentration gradient between intra- and extra-cuff space. In the schematic diagram of the intracuff pressure changes during anesthesia with nitrous oxide, because of concentration gradient of the gas mixture, gases flow from pulmonary side into the cuff and in the latter phase gases pass through the cuff membrane. Our in vitro experimental system was revealed to be useful in accurately assessing the gas permeability through the cuff membrane of a tracheal tube in conditions relevant to clinical uses.

Mash1 regulates the development of C cells in mouse thyroid glands.

In mammals, the ultimobranchial body derived from the fourth pharyngeal pouch gives rise to thyroid C cells. The C cells of newborn mice are immunoreactive for calcitonin, calcitonin gene-related peptide (CGRP), protein gene product (PGP) 9.5 and NeuroD, and transiently exhibit the neuronal markers TuJ1 and somatostatin during fetal development. The basic helix-loop-helix (bHLH) transcription factor Mash1 plays a role in the differentiation of autonomic neurons. We show that in wild-type mouse embryos, Mash1 is expressed in the ultimobranchial body at embryonic day (E) 12.5, when the body is located close to the great arch arteries. It is also expressed in the ultimobanchial body fused with the thyroid lobe at E 13.5. Targeted disruption of Mash1 resulted in the absence of C cells in the mouse thyroid glands, since cells displaying the C-cell markers and expressing NeuroD were not detected during fetal development or at birth. The failure of C-cell formation in the null mutant thyroids was also confirmed by electron microscopy. While the formation and migration of the ultimobranchial body were not affected in the Mash1 null mutants, at E 12.5-E 13.5 both the ultimobranchial body located close to the arteries and the organ populating the thyroid lobe exhibited a marked increase in apoptotic cell numbers. Thus, in the mutant mice, the ultimobranchial body fails to complete its differentiation program and finally dies. These results indicate that Mash1 enhances survival of the C-cell progenitors by inhibiting apoptosis.

Effect of pinealectomy on the photoperiod-dependent changes of the specific secretory cells and alpha-subunit mRNA level in the chicken pars tuberalis.

The effect of pinealectomy on the synthesis of the common alpha-subunit of glycoprotein hormones by the specific secretory cells of the pars tuberalis (PT-specific cells) was examined in male chicks. Expression of melatonin receptor (Mel(1c)) mRNA was demonstrated in the chick pars tuberalis by reverse transcription-polymerase chain reaction analysis. Northern blot analyses revealed that, after pinealectomy, common alpha-subunit mRNA levels were increased in the pars tuberalis of chicks kept under normal lighting (L:D=12 h:12 h), indicating that melatonin inhibits the synthesis of the alpha-subunit of PT-specific cells. Furthermore, alpha-subunit mRNA levels in the pars tuberalis were shown to display similar photoperiod-dependent changes in pinealectomized chicks as in intact animals. Levels of alpha-subunit mRNA in the pars tuberalis were decreased in both pinealectomized and control chicks kept under continuous light (L:D=24 h:0), whereas the levels were enhanced in pinealectomized chicks kept under extended darkness (L:D=1 h:23 h) and under normal lighting. Thus, pinealectomy did not affect the inhibition or stimulation of the alpha-subunit synthesis in the chicken pars tuberalis elicited by continuous light or extended darkness, respectively. Quantitative electron-microscopic analyses showed that, after exposure to continuous light for 30 days, many PT-specific cells were filled with enlarged secretory granules in both pinealectomized and control chicks. Exposure to extended darkness for 30 days caused an increase in the cytoplasmic and nuclear areas of the PT-specific cells. Secretory granules were however larger in pinealectomized than in intact control chicks. These results suggest that the activity of PT-specific cells is mainly regulated by photoperiod.