Modulation of the swallowing reflex by stimulation of the gigantocellular reticular nucleus in the rat

OBJECTIVES

The gigantocellular reticular nucleus (Gi) projects to the nuclues of the solitary tract nucleus (NTS) and the lateral reticular formation (LRF) above the nucleus ambiguus. The swallowing central pattern generator comprises the NTS and the LRF. The present study examined whether stimulation of the Gi affects the swallowing reflex.

METHODS

Experiments were performed on urethane-anesthetized rats. The swallowing reflex was evoked by repetitive electrical stimulation of the superior laryngeal nerve and responses were recorded from the mylohyoid muscle on an electromyogram. The Gi was stimulated electrically. In addition, glutamate was injected into the Gi. The Friedman's test, followed by the Wilcoxon signed-rank test with Bonferroni correction, were used to assess the effects of electrical stimulation of the Gi. The Wilcoxon signed-rank test was used to assess the effects of glutamate injection into the Gi. Differences were considered significant at the P < 0.05 level.

RESULTS

The number of swallows was significantly increased or decreased by electrical stimulation of the Gi or after injection of glutamate into the Gi. In both electrical stimulation of the Gi and injection of glutamate into the Gi, the onset latency of the first swallow was prolonged when the number of swallows was decreased but showed no change when the number of swallows was increased.

CONCLUSIONS

The present results suggest that the Gi is involved in the control of swallowing.

Stimulation of the center of the lateral reticular nucleus suppresses the swallowing reflex in rats

Morphological studies have demonstrated that the lateral reticular nucleus (LRt) receives fibers projected from sites that are related to control of the swallowing reflex. Although the LRt may therefore be related to control of the swallowing reflex, the functional role of the LRt in the swallowing reflex remains unknown. The present study examined whether the swallowing reflex is modulated by stimulation of the LRt. These experiments were performed on rats anesthetized by urethane. The swallowing reflex was evoked by repetitive electrical stimulation of the superior laryngeal nerve (SLN) and was identified by electromyographic activities from the mylohyoid muscle. Electrical stimulation was applied to the LRt or glutamate was injected into the LRt. The number of swallows was reduced, and the latency of the onset of the first swallow was increased during electrical stimulation near the middle of the rostrocaudal direction of the LRt. The number of swallows was reduced, and the latency of onset of the first swallow increased after microinjection of glutamate near the rostrocaudal center of the LRt. The present study suggests that the LRt is involved in control of the swallowing reflex.

Involvement of capsaicin-sensitive nerves in the initiation of swallowing evoked by carbonated water in anesthetized rats

Capsaicin powerfully evokes the swallowing reflex and is a known therapeutic agent for improving dysphagia and preventing aspiration pneumonia. However, the role of capsaicin-sensitive nerves in the initiation of swallowing evoked by various natural stimuli remains unclear. To explore this question, we blocked laryngeal capsaicin-sensitive nerves following the coapplication of QX-314 and capsaicin (QX/Cap), and investigated the effects on swallowing evoked by mechanical and chemical stimulation in anesthetized rats. Swallows were evoked by capsaicin, carbonated water (CW), distilled water (DW), and punctate mechanical stimulation using von Frey filaments applied topically to the larynx. Swallows were documented by recording electromyographic activation of the suprahyoid and thyrohyoid muscles. The initiation of swallowing by capsaicin was strongly suppressed at 5 min following QX/Cap treatment and returned in a time-dependent manner. CW-evoked swallows at 5 min following QX/Cap treatment were significantly diminished compared with before and 30 min after treatment. In contrast, DW-evoked and mechanically evoked swallows were unchanged by QX/Cap treatment. Furthermore, CW-evoked swallows were virtually abolished by transection of the superior laryngeal nerves and significantly decreased by the topical application of acid-sensing ion channel-3 (ASIC3) inhibitor APETx2, but they were not affected by the nonselective transient receptor potential channel inhibitor ruthenium red or the ASIC1 inhibitor mambalgin-1. Taken together, we speculate that capsaicin-sensitive nerves play an important role in the initiation of CW-evoked swallows.NEW & NOTEWORTHY The initiation of swallowing evoked by laryngeal capsaicin and carbonated water application was diminished by the coapplication of QX-314 and capsaicin. Carbonated water-evoked swallows were also abolished by transection of the superior laryngeal nerves and were inhibited by the acid-sensing ion channel-3 inhibitor. Capsaicin-sensitive nerves are involved in the initiation of carbonated water-evoked swallows.

Suppression of the Swallowing Reflex during Rhythmic Jaw Movements Induced by Repetitive Electrical Stimulation of the Dorsomedial Part of the Central Amygdaloid Nucleus in Rats

A previous study indicated that the swallowing reflex is inhibited during rhythmic jaw movements induced by electrical stimulation of the anterior cortical masticatory area. Rhythmic jaw movements were induced by electrical stimulation of the central amygdaloid nucleus (CeA). The swallowing central pattern generator is the nucleus of the solitary tract (NTS) and the lateral reticular formation in the medulla. Morphological studies have reported that the CeA projects to the NTS and the lateral reticular formation. It is therefore likely that the CeA is related to the control of the swallowing reflex. The purpose of this study was to determine if rhythmic jaw movements driven by CeA had inhibitory roles in the swallowing reflex induced by electrical stimulation of the superior laryngeal nerve (SLN). Rats were anesthetised with urethane. The SLN was solely stimulated for 10 s, and the swallowing reflex was recorded (SLN stimulation before SLN + CeA stimulation). Next, the SLN and the CeA were electrically stimulated at the same time for 10 s, and the swallowing reflex was recorded during rhythmic jaw movements (SLN + CeA stimulation). Finally, the SLN was solely stimulated (SLN stimulation following SLN + CeA stimulation). The number of swallows was reduced during rhythmic jaw movements. The onset latency of the first swallow was significantly longer in the SLN + CeA stimulation than in the SLN stimulation before SLN + CeA stimulation and SLN stimulation following SLN + CeA stimulation. These results support the idea that the coordination of swallowing reflex with rhythmic jaw movements could be regulated by the CeA.

Suppressive effect of the swallowing reflex by stimulation of the pedunculopontine tegmental nucleus

This study investigates whether the swallowing reflex is modulated by stimulation of the pedunculopontine tegmental nucleus (PTg). Sprague-Dawley rats under urethane anesthesia were used. The swallowing reflex was induced by electrical stimulation of the superior laryngeal nerve and was identified by the electromyographic activities from the mylohyoid muscle. The number of swallows was reduced by electrical stimulation of the PTg. The latency of the onset of the first swallow was increased during stimulation of the PTg. The duration of electromyogram bursts of the mylohyoid muscle was significantly shorter during the PTg stimulation than with no stimulation. The number of swallows was reduced, latency of onset of the first swallow increased, the duration of electromyogram bursts of the mylohyoid muscle was significantly shorter and the peak-to-peak amplitude of electromyogram bursts of the mylohyoid muscle was significantly suppressed after microinjection of glutamate into the PTg. These results suggest that the PTg is involved in the control of swallowing.

P737Endothelial ERK2/thromboxane receptor pathway induces endothelial dysfunction, insulin resistance and steatohepatosis through superoxide with high fat high sucrose diet

Introduction

Metabolic syndrome (MetS) is well known as the risk of cardiovascular diseases associated with endothelial dysfunction and induces steatohepatosis. Insulin resistance is a major character of MetS, which affects intracellular signaling pathways and endothelial function. Extracellular signal-regulated kinase (ERK) is a major component of insulin signal and many of vasoactive peptides, which were released in MetS, can activate it in endothelium. However, the role of endothelial ERK in nitric oxide (NO) bioactivity in MetS in in vivo has been unknown.

Purpose

The aim of this study is to clarify the role of endothelial ERK2 on NO bioactivity in mice model of MetS.

Methods and results

We created endothelial specific ERK2 knock out mice (EE2KO) crossing Tie2-Cre mice and ERK2 flox mice and fed them with normal or high-fat/high-sucrose diet (HFHSD) for 24 weeks. Serum glucose and insulin levels and HOMA-IR were lowered in EE2KO with HFHSD without changing body weight. In wild type mice (WT) with HFHSD, nonalcoholic fatty liver disease (NAFLD) activity score, fibrosis score and serum ALT level were increased, all of which were blunted in EE2KO. EE2KO with HFHSD lowered systolic blood pressure (WT: 123.7±5.83 mmHg, EE2KO: 101.4±3.66 mmHg, P<0.01, N=8) without changing heart rate, which was increased to the same levels with L-NAME, an endothelial NO synthase inhibitor, in both groups. Serum NO levels measured with serum nitrite/nitrate concentrations were increased in EE2KO with HFHSD (WT: 23.10±3.74 μmol/l, EE2KO: 41.71±6.73 μmol/l, P<0.05, N=12). Endothelial function was assessed with the isometric tension measurement of aortic rings with acetylcholine (ACh). ACh-induced relaxation was improved in EE2KO with HFHSD. Superoxide production of aorta from EE2KO was lowered than WT with HFHSD in dihydroethidium (DHE) staining. S18886, an antagonist of the thromboxane A2-prostanoid (TP) receptor, decreased superoxide production of aorta in DHE staining resulting in improving endothelial function in the isometric tension measurement of aortic rings. Oral administrations of S18886 decreased systolic blood pressure, serum fasting glucose and insulin levels, and surprisingly improved steatohepatosis by decreasing NAFLD activity score and fibrosis score.

Relaxation of aortic rings with ACh

Conclusions

Endothelial ERK2/TP receptor pathway increases superoxide production and decreased NO bioactivity, resulting in deteriorating endothelial function, insulin resistance and steatohepatosis, which were improved by antagonist of the TP receptor in mice model of MetS. The present study indicates that ERK2/TP pathway could be a therapeutic target for complications of MetS.

Routine Referral by Urologists Increase Opportunities for Corneal Donation

BACKGROUND

The levels of corneal donation are insufficient to meet the demand for corneal transplantation in Japan. To overcome this problem, we started to routinely mention the possibility of corneal donation to the families of patients who died in our hospital's Urology Department in February 2008. In this study, we evaluated the effectiveness of this approach.

METHODS

We retrospectively reviewed the medical records of the patients who died in the Department of Urology, St. Marianna University School of Medicine Hospital, and analyzed the patients' characteristics and information about corneal donation.

RESULTS

In total, 211 patients died in our department between February 2008 and March 2017, and 155 patients were medically suitable corneal donors. We mentioned the possibility of corneal donation to 129 (83.2%) families, and 29 (18.7%) families agreed. Three families subsequently withdrew their consent. Finally, 26 (16.8%) of the families that were approached about corneal donation by urologists agreed to donate their relatives' corneas. Another 2 families voluntarily offered to donate their relatives' corneas. Thus, 28 (18.1%) of 155 medically suitable donors donated their corneas for transplantation. Twenty-six (92.8%) donors were 60 years or older and all donors were affected with malignant genitourinary tumors. Fifty-four (96.4%) corneas were successfully transplanted into recipients.

CONCLUSIONS

Even elderly patients who die of solid carcinoma can be an important source of corneal donors. In this study, we showed that routine referral by urologists increased corneal donation. If this approach were adopted by other departments, it might further increase the number of corneal donations.

Effects of gum chewing training on oral function in normal adults: Part 1 investigation of perioral muscle pressure

Background/purpose

The strength of the intraoral and extraoral muscles that assist the function of tooth and jaw movement during mastication is important for performing oral function. The aim of this study was to investigate the usefulness of gum chewing training to improve the swallowing and feeding function.

Materials and methods

In experiment 1, the differences in maximum tongue pressure (TP) and cheek pressure (CP) at the measurement time point for both groups with and without training were examined. We instructed subjects to perform gum chewing training 3 times daily for 3 months. TP and CP were measured before training and at 1, 2, and 3 months after starting training. In experiment 2, the changes of TP and CP based on the sex and duration of training were examined. The effect of the training was evaluated before training, at 2 weeks and 1, 2, and 3 months after starting training, and at 1 and 3 months after cessation of training.

Results

Experiment 1 showed TP and CP increased with the progress of continuous training. In experiment 2, TP and CP were higher in men than in women and markedly increased at 2 weeks and 1 month in both sexes. After cessation of training, TP and CP tended to decrease, but there was no significant difference between 3 months after starting training, and also significantly higher than before training.

Conclusion

This study suggested that gum chewing training is a useful to improve the swallowing and feeding function.

A case of refractory lupus nephritis complicated by psoriasis vulgaris that was controlled with secukinumab

It has been reported that T helper 17 cells are involved in the pathogenesis of systemic lupus erythematosus, but there is no report on interleukin-17-targeted therapy. We report a case of a 62-year-old female who presented with psoriasis vulgaris and refractory lupus nephritis. Because her conditions were resistant to conventional treatment, and flow cytometry confirmed the proliferation of activated T helper 17 cells in peripheral blood, and examination of a renal biopsy tissue sample confirmed infiltration of numerous interleukin-17-positive lymphocytes to the renal interstitium, administration of the anti-interleukin-17A antibody secukinumab was initiated. After starting secukinumab the clinical and biological features were improved.

Acute Electrolyte Disturbances in Coronary Sinus during Left Coronary Arteriography in Man

Electrolyte disturbances, particularly reduction of ionized calcium, induced by iodinated contrast media (CM) are important considerations in coronary arteriography. A study was conducted in 24 patients to evaluate the acute electrolyte alterations in the coronary sinus during left coronary arteriography. During left coronary arteriography, coronary sinus blood was withdrawn for measurement of electrolytes. The CM used were diatrizoate, ioxaglate, iohexol, and iopamidol. The hematocrit was decreased moderately by all 4 CM used at 5 s and returned to the control level at 15 s. The level of ionized calcium was decreased by all CM at 5 s. Prolonged reduction of ionic calcium was observed with diatrizoate and ioxaglate at 15 s. The level of potassium was almost unchanged by diatrizoate and ioxaglate in spite of hemodilution, which may lead us to a hypothesis that potassium can be released from the intracellular spaces such as red blood cells and vascular endothelial cells. Thus the depression of left ventricular function might be caused not only by reduction of ionized calcium, but also by a relative increase in the level of serum potassium.

Age-related decline of cerebral oxygen metabolism in normal population detected with positron emission tomography

Using positron emission tomography (PET), cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) were measured in 32 healthy volunteers aged from 27 to 67 years. In bilateral putamen, left supratemporal, left infrafrontal and left parietal cortices, CMRO2 showed a significant decline during aging. The age-related decline of CBF was seen only at the left superior temporal cortex. The mean CMRO2 was significantly lower in the elder group (over 51 years old) than in the younger group (under 50 years old), whereas no significant difference in mean CBF between the two groups. The poor correlation of CBF to the age could be explained partly by the fact that CBF is easily influenced by the physiological, psychological and/or environmental factors. The age-related changes of CMRO2 were more marked in the association cortices of the left hemisphere than in that of the right hemisphere.

Proposal for research and education: joint lectures and practicals on central nervous system anatomy and physiology

We coordinated anatomy and physiology lectures and practicals to facilitate an integrated understanding of morphology and function in a basic medical science program for dental students and to reduce the time spent on basic science education. This method is a means to provide the essential information and skills in less time. The overall impression was that the practice of joint central nervous system lectures and practicals was an efficient method for students, which suggests that joint lectures might also be useful for clinical subjects. About two-thirds of students felt that the joint anatomy and physiology lecture on the central nervous system was useful and necessary in understanding the relationship between morphology and function, at least for this subject. One-third of students were neutral on the effectiveness of this method. However, the survey results suggest that improvements are needed in the method and timing of joint lectures and practicals. The present teaching approach can be further improved by conducting combined lectures in which the form and function of anatomic structures are presented by the relevant departments during the same lecture. Finally, joint lecturers and practicals offer an opportunity to increase student understanding of the importance of new research findings by the present authors and other researchers.

Optimal heating condition of mouthguard sheet in vacuum-pressure formation: part 3 styrene-based thermoplastic elastomer

BACKGROUND

The aim of this study was to identify suitable heating conditions of polyolefin-polystyrene co-polymer sheets in vacuum-pressure formation, monitor the sheet temperature during molding, and examine the thickness of the fabricated mouthguard.

MATERIALS AND METHODS

Mouthguards were fabricated with polyolefin-polystyrene co-polymer sheets (4.0-mm thick) utilizing a vacuum/pressure-forming device, which was subjected to vacuum forming for 10 s and pressure molding for 2 min. Four heating conditions were compared, defined by the amount of sag distance of 5, 10, 15, or 20 mm from the center of the softened sheet below the clamp. The working model was trimmed to a height of 20 mm at the cutting edge of the maxillary central incisor and to a height of 15 mm at the mesiobuccal cusp of the maxillary first molar. The radiation thermometer was used to measure the sheet temperatures of the center of the heated and non-heated surfaces under each condition. The sheet thickness after fabrication was determined for the incisal and the molar portions, and dimensional measurements were obtained using a measuring device. The differences in the sheet thickness produced by the different heating conditions were analyzed by Games-Howell's multiple comparison tests.

RESULTS

For condition of 5 mm sagged, the temperature on the non-heated surface did not reach a sufficient softening temperature and the thickness was smallest. Mouthguard thickness was largest in the order of 15 mm sagged condition, followed by 20 mm sagged condition and then by 10 mm sagged condition, but a statistical difference was not observed in the labial and the buccal surface among the three conditions.

CONCLUSION

This study demonstrated that for sufficient softening, it was necessary to heat the sheet to obtain a sag of 10 mm or more, and that the mouthguard thickness decreased as the sag increased.

Role of the vestibular nuclear complex in facilitating the jaw-opening reflex following stimulation of the red nucleus

According to our previous studies, stimulation of the red nucleus (RN) facilitates the low-threshold afferent-evoked jaw-opening reflex (L-JOR). It has been reported that the RN projects to the superior (SVN), lateral (LVN) and inferior vestibular (IVN) nuclei. The SVN and the LVN have reciprocal intrinsic connections with the medial vestibular nucleus (MVN). Our previous study demonstrated that stimulation of the vestibular nuclear complex (VN) modulates the L-JOR. These facts suggest that RN-induced facilitation of the L-JOR is mediated via the VN. In the present work we investigated whether electrically induced lesions of the VN, or microinjection of muscimol into the VN, affects RN-induced facilitation of the L-JOR. The L-JOR was evoked by electrical stimulation of the inferior alveolar nerve. The stimulus intensity was 1.2 times the evocation threshold. Lesions of the MVN or the LVN or the SVN, and the muscimol injection into the MVN or the LVN or the SVN, reduced the RN-induced facilitation of the L-JOR. Conversely, lesions of the IVN, and the muscimol injection into the IVN, increased the RN-induced facilitation of the L-JOR. These results suggest that the RN-induced facilitation of the L-JOR is mediated by a relay in the VN.

Evaluation of reliability of perioral muscle pressure measurements using a newly developed device with a lip piece

PURPOSE

We examined the reliability of measurements using a newly developed perioral muscle pressure measuring device with a lip piece in healthy adults.

METHODS

Subjects were 40 healthy men (25.8 years) with normal stomatognathic function. Perioral muscle pressure measuring device with a lip piece was used to measure upper lip, lower lip and tongue pressure, and a balloon-based measurement device was used to measure tongue and cheek pressure. Each measurement was taken twice with a 1-min interval between the two measurements. We determined intra-rater reliability by using the intra-class correlation coefficient as a test of relative reliability. As a test of absolute reliability, Bland-Altman analysis was used to assess systematic bias and the 95% confidence interval of the minimal detectable change was calculated. Additionally, the coefficient of variation was calculated. The Spearman-Brown formula was calculated the number of measurements needed to achieve a confidence coefficient ≥0.9. Each set of measurements was followed by a second set that were taken 1 week later.

RESULTS

All measurements showed high values of intra-class correlation coefficient. Upper lip, tongue, and cheek pressure can be determined based on a single measurement, while lower lip pressure requires averaging twice. No systematic bias was observed. The coefficients of variation of measurements were almost the same between the two devices.

CONCLUSION

Measurements were highly reliable regardless of the type of perioral muscles. Our findings suggest that the method described in this study is useful as a quantitative chair side method for examining perioral muscle pressure.

Suppression of the swallowing reflex by stimulation of the red nucleus

We study whether the red nucleus is involved in control of swallowing. The swallowing reflex was induced in anesthetized rats by repetitive electrical stimulation of the superior laryngeal nerve. The electromyographic activities of the mylohyoid and thyrohyoid muscles were recorded in order to identify the swallowing reflex. Repetitive electrical stimulation applied to the red nucleus reduced the number of swallows. The onset latency of the first swallow was increased during repetitive electrical stimulation applied to the magnocellular part of the red nucleus. Microinjection of monosodium glutamate into the red nucleus also reduced the number of swallows. The onset latency of the first swallow was increased after microinjection of monosodium glutamate into the magnocellular part of the red nucleus. These results imply that the red nucleus is involved in the control of swallowing.

Genome-wide association study identifies a potent locus associated with human opioid sensitivity

Opioids, such as morphine and fentanyl, are widely used as effective analgesics for the treatment of acute and chronic pain. In addition, the opioid system has a key role in the rewarding effects of morphine, ethanol, cocaine and various other drugs. Although opioid sensitivity is well known to vary widely among individual subjects, several candidate genetic polymorphisms reported so far are not sufficient for fully understanding the wide range of interindividual differences in human opioid sensitivity. By conducting a multistage genome-wide association study (GWAS) in healthy subjects, we found that genetic polymorphisms within a linkage disequilibrium block that spans 2q33.3-2q34 were strongly associated with the requirements for postoperative opioid analgesics after painful cosmetic surgery. The C allele of the best candidate single-nucleotide polymorphism (SNP), rs2952768, was associated with more analgesic requirements, and consistent results were obtained in patients who underwent abdominal surgery. In addition, carriers of the C allele in this SNP exhibited less vulnerability to severe drug dependence in patients with methamphetamine dependence, alcohol dependence, and eating disorders and a lower 'Reward Dependence' score on a personality questionnaire in healthy subjects. Furthermore, the C/C genotype of this SNP was significantly associated with the elevated expression of a neighboring gene, CREB1. These results show that SNPs in this locus are the most potent genetic factors associated with human opioid sensitivity known to date, affecting both the efficacy of opioid analgesics and liability to severe substance dependence. Our findings provide valuable information for the personalized treatment of pain and drug dependence.

Role of the lateral reticular nucleus in suppressing the jaw-opening reflex following stimulation of the red nucleus

We found in a previous study that stimulation of the red nucleus (RN) facilitated the low-threshold afferent-evoked jaw-opening reflex (JOR) and suppressed the high-threshold afferent-evoked JOR. It has been reported that the RN projections to the contralateral lateral reticular nucleus (LRt), and stimulation of the LRt inhibits the nociceptive JOR. These facts suggest that RN-induced modulation of the JOR is mediated via the LRt. We investigated whether electrically induced lesions of the LRt, or microinjection of muscimol into the LRt, affects RN-induced modulation of the JOR. The JOR was evoked by electrical stimulation of the inferior alveolar nerve (IAN), and was recorded as the electromyographic response of the anterior belly of the digastric muscle. The stimulus intensity was either 1.2 (low-threshold) or 4.0 (high-threshold) times the threshold. Electrically induced lesion of the LRt and microinjection of muscimol into the LRt reduced the RN-induced suppression of the high-threshold afferent-evoked JOR, but did not affect the RN-induced facilitation of the low-threshold afferent-evoked JOR. These results suggest that the RN-induced suppression of the high-threshold afferent-evoked JOR is mediated by a relay in the contralateral LRt.

Development of Interferon Suppositories. I. Enhanced Rectal Absorption of Human Fibroblast Interferon by Fusogenic Lipid via Lymphotropic Delivery in Rats

We attempted to enhance the rectal absorption of human fibroblast interferon (HuIFN-β) in rats by the administration of suppositories containing fusogenic lipid and a nontoxic surfactant. Suppositories containing either the lipid (linoleic acid) or the surfactant [HCO60; polyoxyethylated (60 mol) hydrogenated castor oil] alone failed to enhance the absorption of HuIFN-β. However, suppositories containing both linoleic acid and HCO60 facilitated the rectal absorption of HuIFN-β. The absorbed HuIFN-β was selectively delivered via the lymph.

Effect of salicylate on the uptake of cefmetazole into brain of mice

Cefmetazole distribution into mice cerebral cortex was minimal when the drug was administered alone. However, the co-administration of salicylate or diethyl maleate enhanced cefmetazole uptake into the cerebral cortex, while it decreased the level of reduced nonprotein sulfhydryls in cerebral cortex. The enhanced cerebral uptake of cefmetazole was suppressed by the simultaneous administration of cysteamine with a concomitant recovery of the reduced nonprotein sulfhydryl concentration in cerebral cortex.

Potentiation of enteral absorption of human interferon alpha and selective transfer into lymphatics in rats

Enhancement of human leucocyte interferon (HuIFN-α) absorption from rat large intestine was studied with the aid of lipid, surfactant and lipid-surfactant mixed micelles. Neither the emulsified lipid (linoleic acid) nor the surfactant (HCO60, polyoxyethylated [60 moles] hydrogenated castor oil) alone were able to enhance the absorption of HuIFN-α. However, linoleic acid-HCO60 mixed micelles enhanced the absorption of HuIFN-α from the large intestine. Highly selective delivery of HuIFN-α into the lymphatics compared to the blood was also observed.

Streamline phenomena in liver metastasis of gastrointestinal tumors - a clinical-study based upon 172 patients

Location and number of liver metastasis of gastrointestinal tumors were detected preoperatively and intraoperatively. The distribution of the liver segment(s) occupied by metastatic tumors varied significantly (p<0.05). Significantly more frequent distributions were demonstrated in the lateral segment with gastric cancer (p<0.05), in the posterior segment with left colic cancer (p<0.001), in the medial segment with rectal cancer (p<0.01), in the anterior segment with bile duct cancer (p<0.05) and the whole of the liver with pancreatic cancer (p<0.05). Significantly less frequent distribution was demonstrated in the posterior segment with gastric cancer (p<0.01). When the liver was divided into the right and the left halves, the distribution of each half of the liver occupied by metastatic tumors varied significantly (p<0.05). Liver metastases of whole colic cancer were significantly more frequent in the right half of the liver (p<0.05). The results suggest that the tumor distribution in liver metastases of gastrointestinal tumors differ depending upon the primary tumors, basically in accordance with the 'streamline' phenomena.

Neuronal activities of the vestibular nuclear complex during mechanically induced rhythmic jaw movements in rats

We studied the neuronal activities of the vestibular nuclear complex (VN) neurons during rhythmic jaw movements in rats anesthetized with urethane. Rhythmic jaw movements were induced by mechanical stimulation of the palate mucosa. The firing rate of approximately 25% of VN neurons increased significantly, and that of 10% of VN neurons decreased significantly, during these rhythmic jaw movements. There was no correlation between the change in the firing rate and the phase of the rhythmic jaw movements (jaw-opening and jaw-closing phases). The neurons that were affected were intermingled in the VN. These results suggest that the VN neurons are involved in controlling jaw movements.

The rostral parvicellular reticular formation neurons mediate lingual nerve input to the rostral ventrolateral medulla

In rats that had been anesthetized by urethane-chloralose, we investigated whether neurons in the rostral part of the parvicellular reticular formation (rRFp) mediate lingual nerve input to the rostral ventrolateral medulla (RVLM), which is involved in somato-visceral sensory integration and in controlling the cardiovascular system. We determined the effect of the lingual nerve stimulation on activity of the rRFp neurons that were activated antidromically by stimulation of the RVLM. Stimulation of the lingual trigeminal afferent gave rise to excitatory effects (10/26, 39%), inhibitory effects (6/26, 22%) and no effect (10/26, 39%) on the RVLM-projecting rRFp neurons. About two-thirds of RVLM-projecting rRFp neurons exhibited spontaneous activity; the remaining one-third did not. A half (13/26) of RVLM-projecting rRFp neurons exhibited a pulse-related activity, suggesting that they receive a variety of peripheral and CNS inputs involved in cardiovascular function. We conclude that the lingual trigeminal input exerts excitatory and/or inhibitory effects on a majority (61%) of the RVLM-projecting rRFp neurons, and their neuronal activity may be involved in the cardiovascular responses accompanied by the defense reaction.

[Thoracic surgery for patients with bronchial asthma]

Thoracic surgery poses a risk for complications in the respiratory system. In particular, for patients with bronchial asthma, we need to care for perioperative complications because it is well known that these patients frequently have respiratory complications after surgery, and they may have bronchial spasms during surgery. If we can get good control of their bronchial asthma, we can usually perform surgery for these patients without limitations. For safe postoperative care, it is desirable that these patients have stable asthma conditions that are well-controlled before surgery, as thoracic surgery requires intrabronchial intubation for anesthesia and sometimes bronchial resection. These stimulations to the bronchus do not provide for good conditions because of the risk of bronchial spasm. Therefore, we should use the same agents that are used to control bronchial asthma if it is already well controlled. If it is not, we have to administer a β₂ stimulator, aminophylline, or steroidal agents for good control. Isoflurane or sevoflurane are effective for the safe control of anesthesia during surgery, and we should use a β₂ stimulator, with or without inhalation, or steroidal agents after surgery. It is important to understand that we can perform thoracic surgery for asthma patients if we can provide perioperative control of bronchial asthma, although these patients still have severe risks.

Effects of neck muscle activities during rhythmic jaw movements by stimulation of the medial vestibular nucleus in rats

This study first examines whether there is rhythmic activity of the neck muscles during cortically induced rhythmic jaw movements in rats anesthetized by urethane. Rhythmic jaw movements were induced by repetitive electrical stimulation of the orofacial motor cortex. An electromyogram in the splenius muscles (spEMG) showed rhythmic bursts during the jaw-opening phase, or during the transition from the jaw-opening phase to the jaw-closing phase. In the sternomastoid (stEMG), however, the electromyogram did not show any bursts during rhythmic jaw movements. A further study then examines whether stimulation of the medial vestibular nucleus (MVN) modulates the rhythmic activity of the neck muscles. Stimuli applied in the jaw-closing phase induced a transient burst in the stEMG, and the duration of activity in the spEMG was increased. Stimuli applied in the jaw-opening phase induced a transient burst in the stEMG and an inhibitory period in the spEMG. These results imply that the MVN is involved in the modulation of neck muscle activities during rhythmic jaw movements induced by stimulating the orofacial motor cortex.

Isolation of a thermotolerant bacterium producing medium-chain-length polyhydroxyalkanoate

AIMS

The aim of this study was to isolate a thermotolerant micro-organism that produces polyhydroxyalkanoates (PHAs) composed of medium-chain-length (mcl) HA units from a biodiesel fuel (BDF) by-product as a carbon source.

METHODS AND RESULTS

We successfully isolated a thermotolerant micro-organism, strain SG4502, capable to accumulate mcl-PHA from a BDF by-product as a carbon source at a cultivation temperature of 45°C. The strain could also produce mcl-PHA from acetate, octanoate and dodecanoate as sole carbon sources at cultivation temperatures up to 55°C. Taxonomic studies and 16S rRNA gene sequence analysis revealed that strain SG4502 was phylogenetically affiliated with species of the genus Pseudomonas. This study is the first report of PHA synthesis by a thermotolerant Pseudomonas.

CONCLUSIONS

A novel thermotolerant bacterium capable to accumulate mcl-PHA from a BDF by-product was successfully isolated.

SIGNIFICANCE AND IMPACT OF THE STUDY

A major issue regarding industrial production of microbial PHAs is their much higher production cost compared with conventional petrochemical-based plastic materials. Especially significant are the cost of a fermentative substrate and the running cost to maintain a temperature suitable for microbial growth. Thus, strain SG4502, isolated in this study, which assimilates BDF by-product and produces PHA at high temperature, would be very useful for practical application in industry.