Diurnal variation in the response of the mandible to orthopedic force

Bone and cartilage metabolism is known to be more active during rest than during periods of activity. The purpose of this study was to examine the hypothesis that mandibular retractive force could be more effective when applied to rats during rest. Mandibular retractive force caused a considerable reduction in the condylar length in experimental groups, and the magnitude of this reduction was greater in the Light-period (08:00-20:00) group than in the Dark-period (20:00-08:00) group. The differentiation and proliferation of chondrocytes were inhibited in animals in the Light-period group, compared with those in the Dark-period group. These results suggest that the orthopedic effects of mandibular retractive force vary depending on the time of day the force is applied, and that such force may be more effective while animals are resting than while they are active.

Estrous-cycle-dependent variation in orthodontic tooth movement

Sex hormones, including estradiol, play important physiological roles in bone metabolism. The purpose of this study was to investigate whether there is estrous-cycle-dependent variation in orthodontic tooth movement, and, if so, to determine the mechanism. Ten-week-old female Wistar rats were used. They received repeated orthodontic force during specific phases in the estrous cycle. Tooth movement in animals that received force principally in estrus was about 33% greater than that in animals that received such force principally in pro-estrus (p < 0.05). Serum estradiol levels also varied according to the estrous cycle, with a peak during pro-estrus and a nadir during estrus, and were inversely related to tooth movement. Furthermore, there were negative correlations between estradiol and both serum TRAP activity and pyridinoline (r = -0.42, p < 0.05; r = -0.59, p < 0.001). These results suggest that cyclic changes in the estradiol level may be associated with the estrous-cycle-dependent variation in tooth movement through its effects on bone resorption.

Complete, long-lasting protection against lethal infectious bursal disease virus challenge by a single vaccination with an avian herpesvirus vector expressing VP2 antigens

Marek's disease herpesvirus is a vaccine vector of great promise for chickens; however, complete protection against foreign infectious diseases has not been achieved. In this study, two herpesvirus of turkey recombinants (rHVTs) expressing large amounts of infectious bursal disease virus (IBDV) VP2 antigen under the control of a human cytomegalovirus (CMV) promoter or CMV/beta-actin chimera promoter (Pec promoter) (rHVT-cmvVP2 and rHVT-pecVP2) were constructed. rHVT-pecVP2, which expressed the VP2 antigen approximately four times more than did rHVT-cmvVP2 in vitro, induced complete protection against a lethal IBDV challenge in chickens, whereas rHVT-cmvVP2 induced 58% protection. All of the chickens vaccinated with rHVT-pecVP2 had a protective level of antibodies to the VP2 antigen at the time of challenge, whereas only 42 and 67% of chickens vaccinated with rHVT-cmvVP2 or the conventional live IBDV vaccine, respectively, had the antibodies. The antibody level of chickens vaccinated with rHVT-pecVP2 increased for 16 weeks, and the peak antibody level persisted throughout the experiment. The serum antibody titer at 30 weeks of age was about 20 or 65 times higher than that of chickens vaccinated with rHVT-cmvVP2 or the conventional live vaccine, respectively. rHVT-pecVP2, isolated consistently for 30 weeks from the vaccinated chickens, expressed the VP2 antigen after cultivation, and neither nucleotide mutations nor deletion in the VP2 gene was found. These results demonstrate that the amount of VP2 antigen expressed in the HVT vector was correlated with the vaccine efficacy against lethal IBDV challenge, and complete protective immunity that is likely to persist for the life of the chickens was induced.

Workplace disability management in postpolio syndrome

Postpolio syndrome (PPS) is generally defined as a clinical syndrome of new weakness, fatigue, and pain in individuals who have previously recovered from acute paralytic poliomyelitis. These new problems may lead to loss of employment as well as new deficits in instrumental activities in daily living (cleaning, washing, shopping, transportation, etc.), walking, climbing stairs, and personal assistance. We presented three cases of PPS with working disabilities in Japan, and stated the issues confronted with. Particularly at the workplace, PPS individuals need special supports from both rehabilitation medicine and occupational health services, including improved nutrition, achieving ideal body weight, regular and sensible exercise, frequent checkups, and modifying working conditions.

[Outcome of rehabilitation for traumatic brain injury in the UOEH Hospital]

We investigated the outcome after patients with traumatic brain injury (TBI) were treated in our hospital. Subjects were 51 patients with TBI (43 men, 8 women; mean age 34.9 +/- 20.3 yr), who had been admitted to the department of rehabilitation in our hospital between 1980 and 2000. Data were collected retrospectively from the medical records. Most injuries were due to motor vehicle accidents. The percentage of patients who suffered impaired cognitive and behavioral functions was 86.3%. The percentage of patients who were discharged to their homes was 70.6%, but none of them could return to work. Patients who were severely disabled in their daily activities or had cognitive and behavioral disturbances were difficult to discharge. We need to establish a comprehensive rehabilitation approach to cognitive and behavioral disturbances for patients with TBI.

[An electrophysiological study of ropivacaine on excised cervical vagus nerves of rabbit]

Ropivacaine, a new long acting local anaesthetic of amide type is structurally related to mepivacaine and bupivacaine. This study was designed to compare the in vitro potency and neurotoxicity of ropivacaine with those of other commercially available local anaesthetics using an isolated rabbit vagus nerve model. Ropivacaine dose-dependently suppressed the evoked compound action potentials of A beta nerve and C nerve components. Minimum concentration of ropivacaine for producing complete suppression of the compound action potentials of all components was 0.008%. Electron microscopic observation showed that ropivacaine did not destroy any peripheral nervous structures in concentrations up to 0.75%. When the neurotoxic effect of ropivacaine was compared, in terms of risk ratio (clinically used concentration/concentrations producing 2 hr irreversible block), with that of commercially available local anesthetics, the rank oder was dibucaine, tetracaine, lidocaine, bupivacaine and ropivacaine.

Screening for acetaldehyde dehydrogenase 2 genotype in alcohol-induced asthma by using the ethanol patch test

BACKGROUND

We have previously reported that alcohol-induced asthma in Japanese patients is caused by increased blood acetaldehyde concentration resulting from abnormalities of acetaldehyde dehydrogenase 2 (ALDH2) enzyme activity on the basis of ALDH2 genotype differences.

OBJECTIVES

The purpose of the present study was to determine whether the ethanol patch test could predict the ALDH2 genotype in Japanese asthmatic subjects.

METHODS

An ethanol patch test on the upper arm and a questionnaire survey addressing the past history of alcohol-induced asthma were administered to 148 adult Japanese asthmatic subjects. The ALDH2 genotypes in these 148 subjects were also determined by means of PCR.

RESULTS

The genotype distribution of ALDH2 determined by PCR in 68 subjects with positive ethanol patch test results was 4 (5.9%), 56 (82.4%), and 8 (11.8%) for genotypes NN (normal homozygote), NM (mutant heterozygote), and MM (mutant homozygote). The ALDH2 genotype in 80 subjects with a negative test result was only NN. The distribution of ALDH2 genotype in 78 (52.7%) subjects who had experienced alcohol-induced asthma symptoms on the basis of the questionnaire was 27 (34.6%), 44 (56.4%), and 7 (9.0%) for genotypes NN, NM, and MM, respectively. On the other hand, 70 subjects had never experienced alcohol-induced asthma symptoms. In these subjects the ALDH2 genotype was NN in 51 (72.9%), NM in 18 (25.7%), and MM in 1 (1.4%).

CONCLUSIONS

Our results indicate that the results of ethanol patch testing correlate well with ALDH2 genotype, as determined by means of PCR, suggesting that the ethanol patch test is useful for the screening of alcohol-induced asthma.

Decreased risk of catheter infection in infants and children using subcutaneous tunneling for continuous caudal anesthesia

Continuous caudal anesthesia has been commonly used for intra- and post-operative analgesia in infants and children. However, it has a potential risk of bacterial infection, especially in infants in whom the catheter site is easily contaminated with loose stool. To avoid infection, the authors applied a new procedure using subcutaneous tunneling for continuous caudal anesthesia. In the 18 cases studied with subcutaneous tunneling, clinical signs of infection were absent and bacterial colonization was not found on the catheter tip after 3.9 +/- 1.4 days of catheterization. The incidence of catheter colonization after continuous caudal anesthesia without tunneling had been reported. In their reports, the incidence of catheter colonization ranged from 20% to 37%. Therefore, caudal catheterization with subcutaneous tunneling is a simple and safe method, and has proved very effective to reduce the risk of epidural infection.

Tooth movement and changes in periodontal tissue in response to orthodontic force in rats vary depending on the time of day the force is applied

The purpose of this study was to investigate whether there are any differences in tooth movement or in the response of periodontal tissue to orthodontic force when the force is applied at different times of the day. One hundred 6-week-old male Wistar rats were divided into one control group without force application and three experimental groups based on the time of day the force was applied to the upper first molars. Animals in the whole-day group received force continuously throughout the experimental period, while animals in the light- and dark-period groups received force only during the light (07:00-19:00) or dark period (19:00-07:00), respectively. Tooth movement was measured using the occlusal view of a precise plaster model with a profile projector. Periodontal tissues were evaluated histologically. The time course of tooth movement varied among the groups. Tooth movement over 21 days in the whole-day and light-period groups was about twice that as in the dark-period group. The formation of new bone on the tension side in the whole-day and light-period groups was more than twice that as in the dark-period group. On the pressure side, more osteoclasts appeared on the alveolar bone in the whole-day and light-period groups than in the dark-period group. The light-period group showed less extensive hyalinization of the periodontal ligament (PDL) than the whole-day group. The area of root resorption on day 21 also varied among the groups. Interference by masticatory forces did not seem to be a principal cause of the decreased tooth movement in the dark-period group. These results indicate that there are considerable variations in tooth movement and in the response of periodontal tissue to orthodontic force when the force is applied at different times of the day in rats. The results suggest that diurnal rhythms in bone metabolism have important implications in orthodontic treatment.

Airway foreign body with clinical features mimicking bronchial asthma

A 56-year-old Japanese male with persistent cough, stridor and diffuse wheezing for 6 months had obstructive pulmonary dysfunction and airway hyperresponsiveness (AHR) to inhaled methacholine. Because of a poor response to glucocorticoid therapy and neutrophilia in the peripheral blood and sputum, chest computed tomography was performed and a plate-like tumor in the truncus intermedius was identified. Fiberoptic bronchoscopy demonstrated a plate-like green-colored tumor firmly impacted into the truncus intermedius and diffuse inflammatory changes spreading to both main bronchi. A piece of 'kombu' (Japanese kelp) was successfully removed by fiberoptic bronchoscopy under general anesthesia. Pulmonary function and methacholine inhalation tests became normal after the removal of the foreign body. In this case, it is suggested that asthma-like symptoms were due to localized airflow limitation in the right bronchus as well as to AHR associated with diffuse airway neutrophilic inflammation.

Plasticity of chemotaxis revealed by paired presentation of a chemoattractant and starvation in the nematode Caenorhabditis elegans

While the basic functioning of the nervous system of Caenorhabditis elegans has been extensively studied, its behavioural plasticities have not been fully explored because of the limited availability of assay systems. We report here a simple form of chemotaxis plasticity in this organism: when worms are starved on plates that contain NaCl, their chemotaxis towards NaCl falls dramatically. This conditioning requires both the presence of NaCl and the absence of a bacterial food source, indicating that it is not merely adaptation or habituation, but that it is likely to be a form of associative learning. While chemotaxis towards volatile chemoattractants does not change significantly after conditioning with NaCl, chemotaxis towards other water-soluble attractants does decrease. This suggests that an altered response of a cell or a group of cells specifically involved in chemotaxis towards water-soluble chemoattractants is responsible for the behavioural alteration. The decrease in chemotaxis occurred slowly over 3–4 h of conditioning and returned quickly to the original level when either of the conditioning stimuli, NaCl or starvation, was removed. The application of serotonin partially blocked this reduction in chemotaxis, consistent with the proposed function of this neurotransmitter in food signalling. Using this assay, we have isolated three mutants with reduced plasticity. This assay system expands the opportunities for studying the molecular and cellular mechanisms of behavioural plasticity in C. elegans.

Duration of exposure to sevoflurane affects dose-response relationship of vecuronium

The purpose of this study was to quantify the relationship between the dose-response curve of vecuronium and duration of exposure to an end-tidal concentration of 1.7% sevoflurane in 67% nitrous oxide and oxygen. Forty adult patients, in groups of 10, were allocated randomly to receive vecuronium by a cumulative dose method at intervals of 15 min (group 15), 30 min (group 30), 60 min (group 60) or 90 min (group 90) after starting inhalation of sevoflurane. Neuromuscular function was monitored by acceleromyographic train-of-four (TOF) responses of the adductor pollicis muscle to ulnar nerve stimulation. Dose-response curves were constructed by least-squares regression analysis and the effective doses of vecuronium (ED50, ED90 and ED95) were estimated and compared between groups. Mean (SEM) ED50, ED90 and ED95 were 16.8 (0.5), 32.6 (1.7) and 40.9 (2.4) micrograms kg-1, respectively, in group 15; 10.6 (1.0), 20.8 (1.7) and 26.2 (2.2) micrograms kg-1, respectively, in group 30; 11.2 (1.1), 21.7 (1.6) and 27.3 (1.8) micrograms kg-1, respectively, in group 60; and 11.0 (1.1), 21.7 (1.6) and 27.5 (1.9) micrograms kg-1, respectively, in group 90. The values obtained in group 15 were significantly higher than those in the other three groups (P < 0.05). The results indicate that the duration of sevoflurane anaesthesia influences the dose-response of vecuronium and 30 min inhalation of 1.7% end-tidal concentration is sufficient to achieve a stable potentiating effect.

Improved hypolipidemic effects of xanthan gum-galactomannan mixtures in rats

This study describes the effects of mixtures of xanthan gum and galactomannan, guar gum, or locust bean gum, on the lipids in plasma and liver in non-diabetic and diabetic rats. Non-diabetic rats were fed cholesterol-free diets with 3% guar gum, locust bean gum, or xanthan gum (3G, 3L, and 3X), or a mixture of xanthan gum and guar gum or locust bean gum (1:2, w/w) (2G1X, 2L1X) for 2 weeks. Rats fed diets not containing these polysaccharides were used as controls. The total cholesterol in plasma and the triacylglycerol in liver were significantly lowered in rats fed the 2G1X diet. The 3G, 3X, 3L, and 2L1X diets showed no significant effect on the total cholesterol and triacylglycerol in plasma and liver. In the streptozotocin-induced (STZ) diabetic rats, the total cholesterol in plasma was lowered in rats fed the 3G, 3X or 2G1X diet for 4 weeks, and the 2G1X diet was more effective than the 3G and 3X diets. The triacylglycerol in plasma in STZ diabetic rats was also significantly lowered by the 2G1X diet. These results showed that a mixture of xanthan gum and guar gum has an improved hypolipidemic effect on non-diabetic and STZ diabetic rats. The effects of the 2G1X diet on the diabetic symptoms in STZ diabetic rats, suppression of food and water intakes, decrease in glucose in urine, and lowering of plasma glucose, were also observed.