Bone cancer increases transient receptor potential vanilloid subfamily 1 expression within distinct subpopulations of dorsal root ganglion neurons

Bone cancer pain has a strong impact on the quality of life of patients but is difficult to treat. Therefore, the mechanisms of bone cancer pain require elucidation for the purpose of development of new therapeutics. A recent study showed that activation of transient receptor potential vanilloid subfamily 1 (TRPV1) was involved in bone cancer pain. In this study, we re-evaluated the analgesic effects of pharmacological blockade of TRPV1 using the potent TRPV1 antagonist 5-iodoresiniferatoxin (I-RTX) and examined whether bone cancer can change TRPV1 expression and distribution in the primary sensory neurons in a mouse model of bone cancer pain. Implantation of osteosarcoma into the femur induced ongoing and movement-evoked bone cancer-related pain behaviors. These behaviors were significantly reduced by i.p. administration of I-RTX, compared with vehicle. Western blot and reverse transcription-polymerase chain reaction (RT-PCR) analyses revealed that TRPV1 level was significantly increased in dorsal root ganglions (DRGs) ipsilateral to sarcoma implantation. Immunohistochemical analysis showed that implantation of osteosarcoma induced not only an increase in the percentage of TRPV1-positive neurons among DRG neurons (24.3+/-1.3% in sham mice and 31.2+/-1.3% in mice with osteosarcoma implantation, P<0.05) but also an overall shift in the distribution of area of profiles to the right. Colocalization study showed that the percentages of colocalization of TRPV1 with neurofilament 200 kD (NF200) and calcitonin gene-related peptide (CGRP) but not isolectin B4 (IB4) among DRG neurons in mice with osteosarcoma implantation were increased compared with those in sham mice (from 0.8+/-0.1% to 2.1+/-0.3% for TRPV1 and NF200 and from 21.1+/-1.3% to 26.5+/-0.2% for TRPV1 and CGRP). In conclusion, TRPV1 activation plays a critical role in the generation of bone cancer pain, and bone cancer increases TRPV1 expression within distinct subpopulation of DRG neurons. These findings may lead to novel strategies for the treatment of bone cancer pain.

Suppression of bone marrow-derived microglia in the amygdala improves anxiety-like behavior induced by chronic partial sciatic nerve ligation in mice

Chronic neuropathic pain causes abnormal sensitivities such as hyperalgesia and allodynia, and emotional abnormalities such as anxiety and depression. Although spinal cord microglia are involved in abnormal sensitivity to neuropathic pain, no previous studies have examined the mechanism of neuropathic pain-induced anxiety. Here, we examined the involvement of bone marrow (BM)-derived microglia aggregated in the amygdalae of mice with chronic neuropathic pain in the development of anxiety-like behavior. We prepared partial sciatic nerve ligations (PSNL) in mice that received bone marrow transplantation from green fluorescent protein (GFP)-Tg mice after irradiation with head protection, and examined GFP-positive microglia in the central nuclei of the amygdalae (CeA). On day 28 after PSNL, BM-derived microglia aggregated in the CeA concurrent with anxiety-like behavior. BM-derived microglia in the CeA highly expressed interleukin (IL)-1β and C-C chemokine receptor type 2 (CCR2). In addition, neurons in the CeA highly expressed monocyte chemotactic protein-1 (MCP-1), a ligand for CCR2, in PSNL-treated mice compared to sham-operated mice, suggesting that the MCP-1/CCR2 axis is involved in the recruitment of BM-derived microglia. Oral administration of a CCR2 antagonist decreased the number of BM-derived microglia in the CeA, and successfully reversed the anxiety-like behavior and hypersensitivity to mechanical stimuli in PSNL-treated mice. Microinjections of an IL-1β receptor antagonist directly into the CeA successfully reversed the anxiety-like behavior in the PSNL-treated mice even though the neuropathic pain persisted. These results suggest that the recruitment of BM-derived microglia to the CeA via the MCP-1/CCR2 axis and neuron-microglia interactions might be important in the pathogenesis of neuropathic pain-induced anxiety.

Endogenous components of event-related potential appearing during NREM stage 1 and REM sleep in man

Information processing in the brain during sleep was studied by analyzing the evoked cortical response to auditory stimulations presented in the odd-ball paradigm. Eight subjects were examined in different sleep stages. The subjects could provide the correct behavioral response to the auditory stimulation by pressing a key button in the light part of stage 1 of NREM sleep, just succeeding to the waking state, but none of the subjects could give the correct behavioral response in the other sleep stages. In the deep part of stage 1 of NREM sleep and REM sleep, a cortical potential corresponding to P300, the endogenous component of the event-related potential (ERP) recorded in the waking state, was recorded in 6 of the 8 subjects in spite of the absence of the behavioral response. In stages 2, 3 and 4 of NREM sleep, emergence of this endogenous component of ERP could not be confirmed. The present findings provide electrophysiological evidence indicating that selective information processing corresponding to sensory discrimination of auditory stimuli is actively performed in stage 1 of NREM sleep and REM sleep.

Electrophysiological evidence suggesting that sensory stimuli of unknown origin induce spontaneous K-complexes

The present study was performed to determine whether or not spontaneous K-complexes are induced by sensory stimuli. In the first part of the present study, sound stimuli were prescribed during sleep in 7 healthy, young, adult subjects. EEG segments in stage 2 sleep were averaged separately according to the presence or absence of an evoked K-complex appearing after each stimulus. The sound stimulus induced N100 and P200 components in averaged EEGs regardless of K-complex appearance. The appearance of N100 and P200 components was considered to be an indicator of the presence of sensory stimuli. In the second part of the present study, EEG segments in stage 2 sleep containing an evoked K-complex or spontaneous K-complex were separately averaged with respect to the peak of N300, one of the main components constituting the K-complex. Small negative and positive components were found just before the main components of spontaneous K-complexes in averaged EEGs. These two components were judged to correspond to N100 and P200 components induced by the sound stimulus, as they appeared just before the main components of the spontaneous K-complex with almost the same lag time between the two components, or between each of the two components and the main components of K-complex, as in the case of N100 and P200 appearing just before the evoked K-complex. The present findings suggest that the spontaneous K-complex is not a spontaneous phenomenon, but that it is induced by sensory stimuli, probably of extracerebral origin.

K-complex evoked in NREM sleep is accompanied by a slow negative potential related to cognitive process

Evoked cortical responses to two kinds of auditory stimuli (rare and frequent) were analyzed to determine whether or not a K-complex evoked in stage 2 of NREM sleep is accompanied by some endogenous cognitive components of the event-related potential. All the 7 subjects examined in this sleep state failed to provide the correct behavioral response to auditory stimuli, but a K-complex was evoked more frequently by rare stimuli than by frequent stimuli. EEG segments in stage 2 were averaged separately according to the presence or absence of K-complexes emerging just after the stimulation. In cases where K-complexes did not emerge, a long-lasting negative potential of relatively low voltage appeared in the difference wave, which was obtained by subtracting the averaged EEG for frequent stimuli from that for rare stimuli. In cases where K-complexes emerged, a similar long-lasting negative potential of large amplitude appeared in the difference wave. These data may indicate that a K-complex evoked by an external stimulus is accompanied by a potential related to a cognitive process, which appears with greater amplitude in cases where a K-complex is evoked.

Protein and energy metabolism in patients with progressive muscular dystrophy

Studies were made on whether body weight loss in patients with muscular dystrophy is due to reduced intake and/or abnormal expenditure of energy. For this, food intakes and various physiological variables were surveyed in totals of 310 patients with Duchenne muscular dystrophy (DMD) of 11 to 29 years old and 28 patients with limb-girdle muscular dystrophy (LGMD) of 30 to 47 years old. Energy and protein intakes, expressed on a unit body weight basis, in DMD patients were comparable to, or higher than the allowances for age-matched healthy controls, whereas those in LGMD patients were 92 and 94% respectively of these allowances. The basal metabolic rate (BMR), expressed as kcal/kg/day, of DMD patients of all ages was higher than that of controls, the difference increasing with age, and being about 20 to 30% higher than that of controls in older patients with DMD. The BMR of LGMD patients was nearly normal. The maintenance requirements of conventional dietary protein in DMD and LGMD patients were 1.26 and 0.84 g/kg/day, respectively. These values were about 68 and 12% higher than the normal adult value (0.75 g/kg/day), indicating decreased protein utilization and increased protein catabolism. Daily excretion of urinary 3-methylhistidine (3MH) per unit muscle mass (micrograms/mg creatinine) by MD patients was significantly higher than that by controls, indicating increased degradation of muscle protein. The BMR, maintenance protein requirement and 3MH excretion of DMD patients suggest that DMD is a hypercatabolic disease. Comparison of the energy and protein intakes with the allowances estimated in consideration of increased requirements showed deficiencies of energy and protein in DMD patients. Thus, we conclude that the underweight of the DMD patients resulted from nutrient deficiencies due to hypercatabolism, despite their considerably high intakes of energy and protein, expressed as per kg body weight. These deficiencies were confirmed by demonstrating decreased concentrations of free essential amino acids, particularly branched chain amino acids, in their serum. The values of variables of LGMD patients were intermediate between those of DMD patients and control subjects.

The effects of excess amino acids on maintenance of pregnancy and fetal growth in rats

The effects of diets, each with an excess of one essential amino acid, on the maintenance of pregnancy and fetal growth were investigated in rats. Rats were fed on 6% casein diet containing 5% threonine, methionine, valine, isoleucine, leucine, tyrosine, phenylalanine, tryptophan, or lysine from day 1 to day 14 or 21 of pregnancy. Excess methionine and leucine diets resulted in complete and 80% loss of fetuses, respectively. This fetal wastage was prevented by daily injection of 0.5 microgram of estrone and 4 mg of progesterone. Judging from the total food consumptions and body weight gains during pregnancy, methionine had the most severe effects, followed in order by leucine, tryptophan, valine, lysine, isoleucine, threonine, phenylalanine, and tyrosine. The weights of fetuses in the excess amino acid groups were significantly lower than those in the respective pair-fed controls. Excess aromatic amino acids caused growth retardation of fetal brain, although the levels of free tyrosine and phenylalanine in fetal brain were not high. The concentrations of free methionine and threonine were markedly elevated in the maternal plasma when these amino acids were fed in excess, but those of other amino acids were not increased appreciably by excess amounts in the diet. Changes in the maternal plasma levels of individual amino acids other than those in excess in the diet were small. On the contrary, the levels of not only the excess amino acids but also of other amino acids in fetal brains were appreciably elevated by these diets. These findings suggest that the blood-brain barrier is immature and that the synthesis of proteins in fetal brain is impaired by excess amino acids in the mothers. The importance of experiments on diets with excess of single amino acids in pregnant animals is discussed in connection with studies on inborn errors of amino acid metabolism.

Biochemical studies on bovine adenovirus type 3. I. Purification and properties

Bovine adenovirus type 3 (BAV3) was purified and its properties were studied. On productive infection of CKT1 cells (a cell line derived from calf kidney) with BAV3, it was observed that viral DNA synthesis was initiated after about 24 h and its rate was maximal after about 40 h. Maturation of the virus occurred several hours after this. Purified BAV3 was separated into four discrete bands by CsCl density gradient centrifugation (complete, incomplete, empty, and degraded viruses). The complete BAV3 was similar in size and structure to human and avian adenoviruses. Polyacrylamide gel electrophoresis showed that the complete BAV3 virion contained at least 10 polypeptides. The total structural proteins of the virion had a similar amino acid composition to those of human adenoviruses. DNA of the complete virus was a linear duplex and its contour length was 12.3 +/- 0.9 mum. The So20,w value of the DNA was 32.9S and its buoyant density in CsCl was 1.717 g/ml. There was about 25% homology between the DNAs of BAV3 and human adenovirus type 5 by filter hybridization. It was also noted that BAV3 produced incomplete virus. The incomplete virus was similar in morphology to the complete virus and contained almost all the structural polypeptides of the latter, but lacked infectivity. However, its DNA had a deletion(s) (13%) which seemed to locate near a terminal.

Landiolol, esmolol and propranolol protect from ischemia/reperfusion injury in isolated guinea pig hearts

PURPOSE

Beta blockers are thought to exert beneficial effects on the ischemic heart. The authors examined the effects of landiolol (ONO 1101), a highly selective beta1 antagonist, propranolol, a nonspecific beta blocker, and esmolol, a selective beta1 antagonist, on postischemic contractile recovery. Drugs were given prophylactically.

METHODS

Ischemia-reperfusion in isolated guinea pig hearts was induced by stopping the perfusion for 45 min and reperfusing for 60 min. Hearts (n = 7 in each group) were treated with or without propranolol (1 or 10 microM), esmolol (5 or 50 microM), or landiolol (20, 100 or 500 microM) ten minutes before inducing ischemia.

RESULTS

At the end of reperfusion, left ventricular pressure (LVP) recovered to 64 +/- 3% of the baseline value in the control group. With 1 and 10 microM propranolol, LVP recovered to 90 +/- 5% and 100 +/- 6% of the baseline value at 60 min after reperfusion, respectively. Fifty microM but not 5 microM of esmolol resulted in restoration of LVP to 97 +/- 17% of the pre-ischemic value at 60 min after reperfusion. In hearts pretreated with 100 and 500 microM landiolol, LVP was restored to 109 +/- 5% and 104 +/- 5% of the baseline value, respectively. Landiolol 100 microM did not depress LVP in the pre-ischemic period.

CONCLUSIONS

The present study shows that landiolol, an ultra-short-acting cardioselective beta1 blocker, has cardioprotective effects on ischemia-reperfusion injury in isolated guinea pig hearts. All three beta blockers were equally protective but the intermediate dosage of landiolol preserved LVP during the pre-ischemic period.

Biochemical studies on bovine adenovirus type 3. II. Incomplete virus

Incomplete virus of oncogenic bovine adenovirus type 3 (BAV3) was highly purified and its biological activity was studied. The production of incomplete virus was found to increase with a high multiplicity of infection and with a large amount of arginine in the growth medium. On infection of contact-inhibited mouse cells, incomplete virus induced cellular DNA synthesis and focus formation. Moreover, this virus was oncogenic to newborn hamsters. On infection of calf kidney cells, a permissive cell line, viral early and late RNA, viral DNA, and almost all the viral late proteins were produced, but no mature progeny virus was detected. It is, therefore, suggested that incomplete virus of BAV3 may be unable to synthesize a protein(s) (perhaps a kind of maturation protein[s]) essential for assembly of viral macromolecules for maturation.

Immunohistochemical analysis of acid-sensing ion channel 2 expression in rat dorsal root ganglion and effects of axotomy

Several studies have suggested that acid-sensing ion channel 2 (ASIC2) plays a role in mechanoperception and acid sensing in the peripheral nervous system. We examined the expression and distribution of ASIC2 in the rat dorsal root ganglion, the co-localization of ASIC2 with tropomyosin-related kinase (trk) receptors, and the effects of axotomy on ASIC2 expression. ASIC2 immunoreactivity was observed in both neurons and satellite cells. ASIC2-positive neurons accounted for 16.5 +/- 2.4% of the total neurons in normal dorsal root ganglion. Most ASIC2-positive neurons were medium-to-large neurons and were labeled with neurofilament 200 kD (NF200). Within these neurons, ASIC2 was not evenly distributed throughout the cytoplasm, but rather was accumulated prominently in the cytoplasm adjacent to the axon hillock and axonal process. We next examined the co-localization of ASIC2 with trk receptors. trkA was expressed in few ASIC2-positive neurons, and trkB and trkC were observed in 85.2% and 53.4% of ASIC2-positive neurons, respectively, while only 6.9% of ASIC2-positive neurons were co-localized with trkC alone. Peripheral axotomy markedly reduced ASIC2 expression in the axotomized dorsal root ganglion neurons. On the other hand, intense ASIC2 staining was observed in satellite cells. These results show that ASIC2 is expressed in the distinct neurochemical population of sensory neurons as well as satellite cells, and that peripheral axotomy induced marked reductions in ASIC2 in neurons.

Phasic EEG activities associated with rapid eye movements during REM sleep in man

Human cortical potentials associated with rapid eye movements (REMs) during REM sleep were recorded in 6 normal young adults by using the averaging technique. The potentials were compared with those recorded during voluntary saccades in the waking state in a dark or an illuminated room. A positive potential of relatively long duration with peak latency of about 200 msec and a wide spread bilateral distribution and of highest amplitude in the mid-parietal area appeared only during REM sleep. It is suggested that this positive potential is phasic EEG activity appearing in association with REMs during REM sleep in man. Comparison of this positive potential with P300s induced by task-irrelevant visual stimuli disclosed that they resemble each other. The possibility was discussed that this positive potential occurring in association with REMs during REM sleep is indeed a P300 appearing in response to visual images in dream.

Effects of postnatal undernutrition on the catecholamine and serotonin contents of suckling rat brain

The effect of postnatal undernutrition on the catecholamine and serotonin contents of various parts of the brain of suckling rats was examined. Undernourishment was induced by increasing the litter size to 18 pups from day 1 to 21 after birth. In control pups, the total amounts of norepinephrine and dopamine in the whole brain increased greatly during the suckling period (norepinephrine: 17.7 ng at birth, 154 ng on day 10, and 420 ng on day 21; dopamine: 12.6 ng at birth, 269 ng on day 10, and 1,022 ng on day 21). Similar, but less marked increases in the norepinephrine and dopamine contents of the brain were observed in malnourished pups. The norepinephrine contents of the forebrain, cerebellum, and brain stem of malnourished pups were comparable with those of normal pups on day 10 but the contents of the cerebellum and brain stem were significantly less than those of normal pups on day 21. Postnatal malnutrition also led to a significant decrease in the dopamine content of the forebrain. In contrast, the serotonin content of the brain of undernourished pups was significantly higher than that of controls. The control pups at the end of suckling period were significantly higher than those of undernourished pups (forebrain: 18.3 pmol in controls and 11.5 pmol in malnourished pups; brain stem: 12.3 pmol in controls and 9.8 pmol in malnourished pups). The tyrosine hydroxylase activity (pmol/g) correlated more closely with the norepinephrine content than with the dopamine or norepinephrine plus dopamine content. The tyrosine and phenylalanine contents of the brain were similar in the two groups. It is concluded from these findings that the catecholamine content of the brain is regulated by the enzyme activity rather than the levels of precursor amino acids.

Cortical reactivity in REM sleep with tonic mentalis EMG activity induced by clomipramine: an evaluation by slow vertex response

Slow vertex response (SVR) to sound stimuli was used as an index to assess whether cortical reactivity in REM sleep with tonic mentalis EMG activity (stage 1-REM) corresponds to that in REM sleep or rather to that in stage 1 of NREM sleep. In 11 young adult subjects 3 night polygraphic records were made after administration of 25 or 50 mg of clomipramine or non-active placebo. Stage 1-REM was observed in the drug night in 8 of the 11 subjects. N1-P2 and P2-N2 amplitudes of SVR were markedly smaller in stage 1-REM than in stage 1, but were virtually of the same height in stage 1-REM and in stage REM. This indicates that cortical reactivity in stage 1-REM closely resembles the counterpart in stage REM. This finding corresponds well with the frequent emergence of vivid dreams in stage 1-REM, indicating that stage 1-REM observed in the present subjects probably represents REM sleep without muscle atonia.

Involvement of transient receptor potential vanilloid subfamily 1 in endothelin-1-induced pain-like behavior

Although local administration of endothelin-1 (ET-1) is known to evoke spontaneous pain, the mechanism of ET-1-induced pain has not been elucidated. We investigated the involvement of protein kinase C (PKC) and transient receptor potential vanilloid subfamily 1 (TRPV1) in ET-1-induced pain-like behavior. Intraplantar ET-1 evoked pain-like behaviors, including licking, flinching, and biting, in a dose-dependent manner in wild-type mice. ET-1-induced pain-like behavior was attenuated by an endothelin type A receptor antagonist but not by PKC inhibitors and was also attenuated in TRPV1-deficient (KO) mice. In addition, we found a significant reduction of spinal Fos expression caused by the same dose of ET-1 in KO mice compared with that in wild-type mice. This study showed that endothelin type A receptor and TRPV1 are involved in ET-1-induced pain-like behaviors but failed to reveal the contribution of PKC.

Less postoperative sore throat after nasotracheal intubation using a fiberoptic bronchoscope than using a Macintosh laryngoscope: A double-blind, randomized, controlled study

STUDY OBJECTIVE

To evaluate whether nasotracheal intubation using a fiberoptic bronchoscope reduces postoperative sore throat.

DESIGN

Prospective, double-blinded, randomized, and controlled study.

SETTING

Postoperative areas and surgical ward of a university hospital.

PATIENTS

Seventy-four patients with American Society of Anesthesiologists physical status I-II who were scheduled for elective general anesthesia requiring nasotracheal intubation.

INTERVENTIONS

Patients were randomized to one of two intubation groups, F (fiberoptic bronchoscope-guided) and M (Macintosh laryngoscope-guided), and after induction of general anesthesia, the patients' tracheas were intubated via the nose.

MEASUREMENTS

The intensity of postoperative sore throat was evaluated using a numerical rating score (0=none, 10=severe) at 24 hours postoperatively, and the incidence of nasal mucosal trauma, time to completion of intubation, and hemodynamic responses were recorded and compared between groups.

MAIN RESULTS

The numerical rating score value was significantly lower in group F than in group M (P=.0047), but the incidence of nasal mucosal trauma was comparable between the two groups. The median time to completion of intubation was shorter for group F than group M (P<.0001). Hemodynamic responses were not significantly different.

CONCLUSIONS

Fiberoptic bronchoscope-guided intubation is associated with less sore throat after nasotracheal intubation than M intubation. The time to completion of intubation was significantly shorter using the fiberoptic bronchoscope than that using the Macintosh laryngoscope.

Biochemical studies on bovine adenovirus type 3. IV. Transformation by viral DNA and DNA fragments

By the calcium technique, intact DNA of bovine adenovirus type 3 (BAV3) was found to transform A31 cells, a clone of BALB/3T3. Transforming activity was resistant to RNase and Pronase but sensitive to DNase. The efficiency of transformation was approximately 5 to 10 foci per mug of DNA. Attempts were also made to test for transforming activity of BAV3 DNA fragments prepared with restriction endonucleases EcoRI and HindIII. The activity was found to associate exclusively with the EcoRI D fragment mapped in the region of 3.6 and 19.7 units (molecular weight, 3.9 x 10(6)). No transformation could be obtained with three HindIII fragments, J, E, and B, located at the left-hand end of the BAV3 genome. However, the enzymatic joining of J and E fragments (0 to 11.9 map units) with a ligase restored the transforming activity. These results suggest that all the genetic information of BAV3 required for transformation is located in the region between 3.6 and 11.9 units on the viral genome. Some properties of A31 cells transformed by BAV3 DNA EcoRI D fragment (TrD) and the ligated DNA of HindIII J and E fragments (TrJE), as well as those transformed by whole BAV3 DNA (Tr), were examined. As compared to untransformed A31 cells, all the transformed cell lines tested showed rapid growth, high saturation densities, and anchorage-independent growth. Moreover, they contained BAV3-specific T antigen and induced tumors in adult nude and BALB/c mice. These properties of Tr, TrD, and TrJE lines were similar to those of BAV3-transformed cells.

A negative component superimposed on event-related potentials during light drowsiness

The present study examined the nature of the negative shift of event-related potential (ERP) recorded during the fully awake state, wakefulness with minor awareness deficit (light drowsiness) and stage 1 of NREM sleep. The cortical responses evoked by two types of auditory stimuli were recorded in nine subjects at the different levels of consciousness described above. A negative component with peak latency of 250-350 msec, N300, was identified in ERP during light drowsiness but not in the fully awake state. In stage 1a (stage 1 without vertex sharp waves), the amplitude of N300 was higher than that in light drowsiness, and it was higher in stage 1b than in stage 1a. The scalp distribution of N300 was predominantly on the vertex. It also confirmed that the vertex sharp wave evoked during stage 1 is maximal on the vertex and its peak latency is approximately 300 msec. Considering the similarity in scalp distribution and peak latency between N300 and vertex sharp wave, it is possible that these electroencephalogram phenomena are generated by an identical synchronizing mechanism in the brain. We assumed that N300 observed during light drowsiness may be an incomplete product of vertex sharp wave.