Effect of volitional relaxation and motor imagery on F wave and MEP: do these tasks affect excitability of the spinal or cortical motor neurons?

OBJECTIVE: To test if simple motor imagery, like thumb abduction, preferentially influences the excitability of the spinal or cortical motoneurons. METHODS: Ten healthy subjects underwent two separate experiments, each consisting of recording F waves and MEPs from abductor pollicis brevis (APB) in three consecutive sessions: (1) baseline, (2) after immobilizing APB for 3 h, and (3) after brief muscle exercise. During the immobilization, the subjects were instructed to volitionally relax APB in experiment 1 (relaxation task), and mentally simulate thumb abduction without actual movement in experiment 2 (imagery task). RESULTS: Relaxation task suppressed both MEPs and F waves. Motor imagery reduced this suppression, restoring F waves nearly completely (94%) and MEPs only partially (77%). Hence, the rest-induced decline of MEPs in part results from cortical modulation. In contrast, statistical analysis revealed no differences in imagery-induced recovery of motoneuron excitabilities whether assessed by F wave or MEP. Thus, increased excitability of spinal motoneurons responsible for F-wave changes also accounts for recovery of MEPs. CONCLUSIONS: Volitional relaxation depresses the spinal and cortical motoneurons, whereas mental simulation counters rest-induced suppression primarily by restoring spinal excitability. SIGNIFICANCE: The present findings help elucidate physiologic mechanisms underlying motor imagery.

Prevention of corticosteroid-induced osteonecrosis in rabbits by intra-bone marrow injection of autologous bone marrow cells.

OBJECTIVES: Femoral head osteonecrosis (ON) is a serious complication of steroid administration. We evaluated bone marrow transplantation (BMT) for preventing corticosteroid-induced ON. METHODS: Rabbits, injected with methylprednisolone (MPSL; 20 mg/kg), were divided into four groups: (i) MPSL alone; MPSL injection only, (ii) MPSL+needling; 2 days after MPSL injection, a hole (1.2 mm diameter) was drilled from the outer cortex 2.5 cm distal to the proximal end of the greater trochanter, (iii) MPSL+saline; 2 days after MPSL injection, 2 ml saline was injected directly into the bone marrow cavity, and (iv) MPSL+BMT; 2 days after MPSL injection, 1 x 10(7)/2 ml bone marrow cells (BMCs) were injected directly into the bone marrow cavity. Platelets, fibrinogen, prothrombin time and total cholesterol in peripheral blood were measured before and after treatment. Tissues were stained with haematoxylin and eosion and terminal deoxynucleotidyl-mediated deoxyuridine triphosphate nick-end labelling stain and immunostained for VEGF, while cell proliferation and viability of whole BMCs in the femur were analysed by cell cycle analysis and [(3)H]-thymidine uptake. RESULTS: The ON incidence in rabbits treated with MPSL alone, MPSL+needling and MPSL+saline was 72.7, 70.0 and 66.7%, respectively, while in the MPSL+BMT group, the incidence was 0%. Serological findings in the MPSL+BMT group were almost normalized. VEGF and TUNEL staining were reduced in the MPSL+BMT group compared with all other groups. There were significantly fewer BMCs in G1 phase from the MPSL+BMT group than the other groups, while uptake of [(3)H]-thymidine was significantly increased. CONCLUSION: Direct injection of autologous BMCs into femurs prevents corticosteroid-induced ON following treatment with high-dose, short-term steroids.

Comparison of Gd-DTPA-induced signal enhancements in rat brain C6 glioma among different pulse sequences in 3-Tesla magnetic resonance imaging.

BACKGROUND: T1-shortening contrast media are routinely used in magnetic resonance (MR) examinations for the diagnosis of brain tumors. Although some studies show a benefit of 3 Tesla (T) compared to 1.5T in delineation of brain tumors using contrast media, it is unclear which pulse sequences are optimal. PURPOSE: To compare gadopentetate dimeglumine (Gd-DTPA)-induced signal enhancements in rat brain C6 glioma in the thalamus region among different pulse sequences in 3T MR imaging. MATERIAL AND METHODS: Five rats with a surgically implanted C6 glioma in their thalamus were examined. T1-weighted brain images of the five rats were acquired before and after Gd-DTPA administration (0.1 mmol/kg) using three clinically available pulse sequences (spin echo [SE], fast SE [FSE], fast spoiled gradient echo [FSPGR]) at 3T. Signal enhancement in the glioma (E(T)) was calculated as the signal intensity after Gd-DTPA administration scaled by that before administration. Pulse sequences were compared using the Tukey-Kramer test. RESULTS: E(T) was 1.12+/-0.05 for FSE, 1.26+/-0.11 for FSPGR, and 1.20+/-0.11 for SE. FSPGR showed significantly higher signal enhancement than FSE and comparable enhancement to SE. CONCLUSION: FSPGR is superior to FSE and comparable to SE in its ability to delineate rat brain C6 glioma in the thalamus region.

Instrumentation and methodology for quantitative pre-clinical imaging studies.

Radiotracer imaging studies performed on animals have the potential to play a major role in pharmaceutical development, pharmacology studies and basic biochemistry research. Recent developments in instrumentation and imaging methodology make it possible to image and quantify the kinetics of radiolabelled pharmaceuticals in a wide range of animal models from rodents to non-human primates. This article reviews the developments which have led to the current state-of-the-art, including advances in detector technologies, image reconstruction and tracer kinetic modelling. The practical issues specific to animal imaging studies are also discussed. With appropriate instrumentation and rigorous methodology, quantitative pre-clinical imaging has an important role to play in drug development.

Porous apatite-wollastonite glass-ceramic as an intramedullary plug.

We evaluated the efficacy and biocompatibility of porous apatite-wollastonite glass ceramic (AW-GC) as an intramedullary plug in total hip replacement (THR) for up to two years in 22 adult beagle dogs. Cylindrical porous AW-GC rods (70% porosity, mean pore size 200 microm) were prepared. Four dogs were killed at 1, 3, 6 and 12 months each and six at 24 months after implantation. Radiological evaluation confirmed the efficacy of porous AW-CG as an intramedullary plug. Histological evaluation showed osteoconduction at one month and resorption of the porous AW-GC, which was replaced by newly-formed bone, at 24 months. Our findings indicate that porous AW-GC can be used clinically as an intramedullary plug in THR.

yam8(+), a Schizosaccharomyces pombe gene, is a potential homologue of the Saccharomyces cerevisiae MID1 gene encoding a stretch-activated Ca(2+)-permeable channel.

The Saccharomyces cerevisiae MID1 gene encodes a stretch-activated Ca(2+)-permeable channel. In a protein database, we found a Schizosaccharomyces pombe gene whose predicted protein shows 26% identical and 62% similar to the Mid1 channel in amino acid sequence. cDNA derived from this gene, designated yam8(+), was isolated by reverse transcription-polymerase chain reaction (RT-PCR). Further analysis showed that the Yam8 protein consists of 486 amino acids and has 6 hydrophobic segments. The yam8(+) cDNA, placed under the S. cerevisiae TDH3 promoter, partially complemented the mating pheromone-induced death (mid) phenotype of the S. cerevisiae mid1 mutant. The expression of the yam8(+) cDNA in the mid1 mutant cells partially remediated the mid phenotype and resulted in a slight increase in Ca(2+) uptake activity. These findings suggest that Yam8 is a potential homologue of Mid1.

Effects of orchidectomy on bone metabolism in beagle dogs.

The effects of orchidectomy on bone metabolism in male beagle dogs were examined using twelve 2-year-old dogs that were orchidectomized. The dogs' bilateral iliac bones, double-labeled with tetracycline and calcein for the histomorphometry, were obtained from three dogs prior to orchidectomy and at 3, 6, 9, and 12 months afterwards. The serum biochemical constituents related to bone metabolism were examined before and every month after orchidectomy. Between 1 and 6 months after orchidectomy, the value of serum testosterone decreased (1 month), while the levels of parathyroid hormone, calcitonin, total calcium, osteocalcin, and alkaline phosphatase activity increased significantly, indicating a high bone turnover. The mean trabecular thickness and the fraction of labeled osteoid surface decreased significantly 3 months after orchidectomy, but other histomorphometric parameters were unchanged. In the period 7-12 months after orchidectomy, the parathyroid hormone level increased ever and above that of the first 6-month period, while the levels of calcitonin, osteocalcin, alkaline phosphatase activity, and phosphorus decreased. The bone volume, mean trabecular thickness, and the fraction of labeled trabecular surface decreased significantly compared with the pre-orchidectomy values. These findings indicate an imbalance in bone metabolism (i.e. bone resorption > bone formation). These results indicate that a loss of bone volume accompanied the fall in sex hormone levels following orchidectomy and suggest that the orchidectomized dog is available as an animal model for studying osteoporosis caused by hypogonadism and the decline of sex functions in men.

Experimental studies on bovine Hyena disease induced by administration of excessive vitamin AD3E premix, vitamin A, or vitamin D3.

The effects of the excessive administration of the vitamin AD3E(V-AD3E) premix, vitamin A (V-A) or vitamin D3 (V-D3) on experimental development of Hyena disease in the calves were examined. Hyena disease was recognized in 4 calves, both of the 2 calves administered a high dose of V-AD3E premix (V-A 3,000,000, V-D3 300,000, and V-E 1,200 IU/day, V-AD3E group), 1 of the 2 calves administered a half dose of the V-AD3E premix, and 1 of the 2 calves administered only V-A (V-A 3,000,000 IU/day, V-A group) when each vitamin was administered orally for 10 days from 1 week after birth. Both of 2 calves administered only V-D3 (V-D3 300,000 IU/day) did not developed. In the 4 calves with Hyena disease (Hyena calves), the plasma retinylpalmitate showed high values which was suggesting the hypervitaminosis A, and the epiphysial growth plate was narrow and destroyed structure of column. Compared with the Hyena calf in the V-A group, the Hyena calves in the V-AD3E group showed earlier appearance time of Hyena disease, lower growth rate and shorter lengths of fore and hind limb bones. In conclusion, the present findings suggested that excessive V-A administration to suckling calves might cause Hyena disease by V-A effects to the epiphysial growth plate, moreover such effects may be promoted by the V-D3.

Changes in histomorphometric values of iliac trabecular bone and serum biochemical constituents related to bone metabolism in beagle dogs during growth.

Changes in histomorphometric values of iliac trabecular bone and serum biochemical constituents related to bone metabolism in normal beagle dogs during growth were examined. A total of 90 dogs (male; 46, female; 44) aged 3, 6, 9, 12 and 24 months, were used. Each dog was injected with tetracycline hydrochloride and calcein for double bone labeling in order to quantitatively measure dynamic as well as static parameters in bone histomorphometry and a part of the ilium was later removed. The measurements on cancellous bone areas of undecalcified iliac sections were performed with a semiautomatic image analyzer. There were no sex significant differences in histomorphometric values except for mineralization lag time at the age of 3 months. In the static parameters, bone volume and mean trabecular thickness increased from 3 to 9 months of age. Bone surface area and mean osteoid thickness increased up to 6 months. Osteoid volume and osteoid surface area decreased up to 6 months of age. As to the dynamic parameters, the mineral apposition and bone formation rates decreased from 3 to 12 months of age. Mineralization lag time increased from 3 to 9 months of age. However, high bone surface area values in both sexes and low osteoid thickness values in females were seen at the ages of 9 and 12 months. Low values of trabecular thickness in both sexes, osteoid thickness and mineralization lag time in males and mineral apposition rate in females were also noted at the age of 12 months. Serum total calcium did not show any specific tendency.(ABSTRACT TRUNCATED AT 250 WORDS)

Intracellular free calcium level and its response to cAMP stimulation in developing Dictyostelium cells transformed with jellyfish apoaequorin cDNA.

A new method is described for measuring intracellular free calcium concentrations, [(Ca2+)i], in the cells of Dictyostelium discoideum transformed with apoaequorin cDNA of the jellyfish, Aequorea victoria. Aequorin, a calcium-specific indicator, was regenerated in vivo from apoaequorin produced in the cells by incubation with coelenterazine. The results showed that [(Ca2+)i] in developing cells markedly increases at the aggregation stage and again at the culmination stage after a temporary drop at the migration stage. Except for the vegetative stage, the cells at all stages of development exhibit a sharp transient increase in [(Ca2+)i] upon stimulation with a cAMP (50 nM) pulse, high responses being observed at the migration and culmination stages. Separated prestalk cells of migrating slugs contain more than twice as much [(Ca2+)i] and show three times as large a response to cAMP stimulation as prespore cells.

Histomorphometric changes in iliac trabecular bone during pregnancy and lactation in beagle dogs.

Changes in bone metabolism throughout pregnancy and lactation in female beagle dogs were examined by histomorphometry and measurement of serum biochemical constituents related to bone. A total of eight dogs, including one dog observed repeatedly from 1 year and 8 months to 4 years and 7 months of age, were used. For double bone labeling to obtain the bone dynamic parameters, dogs were each injected twice, at an interval of 7 days, with fluorochromes such as tetracycline or calcein at the time just after mating, just after delivery, and before weaning. At the time just after weaning, the iliac bone was biopsied. Histomorphometric analysis of trabecular bone area of undecalcified iliac bone sections was performed using a semiautomatic image analyzer. Serum biochemical parameters related to bone such as parathyroid hormone, calcitonin, calcium, phosphorus and alkaline phosphatase activity were periodically measured. Bone histomorphometric analysis revealed significant increases in the mean values of osteoid volume and mineral apposition rate as compared with those of age-matched no pregnancy dogs. The mineral apposition rate measured with the passage of time was increased after delivery and was further increased before weaning compared with that at the time of mating. There were no significant changes in mean values of bone volume, mean trabecular thickness, bone formation rate and mineralizing lag time.(ABSTRACT TRUNCATED AT 250 WORDS)

[Age-related changes in bone weights and their components in rats].

Age-related changes in the wet, dry and ash weights and components such as water, organic substance, ash, calcium and phosphorus of femur, tibia and first lumbar vertebra and serum biochemical constituents related to bone metabolism were examined in Wistar rats. A total of 60 males and 60 females were used, and every five rats of both sexes were examined at 1 and 2 months of age and then at intervals of 3 months between 3 and 30 months of age. Each bone weight increased rapidly up to 3 months of age and then gradually up to 12 months of age in females and 9 months of age in males, but thereafter decreased at 27 and 30 months of age in males. Between 1 and 6 or 9 months of age in both sexes, a decrease in water content, increases in ash, calcium and phosphorus, and almost no change in organic substance in each bone were observed. After 15 months of age in males, an increase in water content, decreases in ash content, calcium and phosphorus, and almost no changes in organic substance were observed in males. The value of serum calcium decreased up to 12 months of age but then increased after 18 months of age in both sexes. Serum phosphorus and alkaline phosphatase activity decreased up to 9 months of age in both sexes. The data obtained in this study supported the results in our previous study that the peak bone strength of the femur and peak bone volume of trabecular bone of the proximal metaphysis of the tibia were at 12 months of age in both sexes in Wistar rats.

Comparison of histomorphometric values in iliac trabecular bone of beagle dogs raised under different breeding systems.

In order to clarify individual differences in bone metabolism among colony-raised beagle dogs, histomorphometric values of iliac trabecular bone and values of serum biochemical constituents related to bone were examined in 10 and 17 beagle dogs raised, respectively, under our two breeding systems in which differences in factors such as exercise, ultraviolet rays, and mineral content of the diet affect bone metabolism. At the age of 14 months, all dogs were injected with tetracycline hydrochloride and calcein twice for double bone labeling in order to measure dynamic as well as static parameters by bone histomorphometry and the ilium was later biopsied. The measurement on cancellous bone areas of undecalcified iliac sections was performed with a semiautomatic image analyser. Values of total calcium, phosphorus, alkalinephosphatase activity, parathyroid hormone and calcitonin in serum were also determined. The results showed that there were no significant differences between the two groups in histomorphometric values, except for the osteoid volume (p less than 0.05) and osteoid surface/trabecular surface ratio (p less than 0.01) in females, or in serum biochemical constituents, except for alkalinephosphatase activity (p less than 0.001) in males, indicating there were virtually no individual differences in bone metabolism in normal colony raised beagle dogs.

[A case report of reflex sympathetic dystrophy treated with nifedipine].

Reflex sympathetic dystrophy (RSD) refers to a symptom complex observed after nerve injury and consists primarily of severe burning pain associated with sensory, vasomotor and trophic phenomena. A 54-year-old male had undergone nephrectomy. At surgery left XIth intercostal nerve had been injured by cautery. After a few weeks following surgery, the patient developed progressive deep burning pain, stabbing sensation and dysesthesia in the left abdominal region. Analgesics and narcotics were ineffective. We diagnosed his case as RSD. He received nifedipine 10mg sublingually. Pain relief was obtained within 10min and lasted for 6hs. Consequently, nifedipine therapy was started at a daily dose of 30 to 60mg. His symptoms were markedly improved within 4 weeks. After 3 months his pain resolved. At the present, some pain often returns, but nifedipine is effective. Nifedipine may be useful as a drug for the management of reflex sympathetic dystrophy.

[The analgesic and antipyretic effects of a non-steroidal antiinflammatory agent, EB-382, in experimental animals].

The analgesic and antipyretic effects of EB-382 as a new non-steroidal antiinflammatory agent were examined in mice and rats. EB-382 had an equipotent inhibition to ibuprofen on the writhing syndrome caused by acetic acid, phenylquinone and acetylcholine in mice, but phenylbutazone was less potent in these experiments. EB-382 had a much more potent inhibition on the pain by the Randall-Selitto method and silver nitrate-induced arthritic pain in rats than ibuprofen and phenylbutazone. EB-382 had no analgesic effect on the pain of non-treated foot by the Randall-Selitto method in rats and by the hot-plate method in mice. EB-382 had a much more potent inhibition on the yeast-induced chronic inflammatory and adjuvant arthritic pains in rats than ibuprofen and phenylbutazone. The antipyretic activity of EB-382 was almost equipotent to that of ibuprofen in rats. EB-382 had no effect on the normal body temperature in rats, which was different from aminopyrine. The above results suggest that EB-382 will be a useful analgesic agent with an antipyretic antiinflammatory activity in clinical studies.

Combination chemotherapy with CDDP and 5-FU in head and neck cancer.

Combination chemotherapy with CDDP and 5-FU was performed in 19 patients with evaluable head and neck cancer and 2 CR patients and 7 PR patients were obtained; thus the response rate was 47.4%. Histologically, the present therapy is considered to be especially effective against well differentiated squamous cell carcinoma (83.3%). The present therapy is considered to be useful as a neo-adjuvant chemotherapy (75.0%), but it is desirable to perform at least 2 courses of treatment. The side effects observed were nausea, vomiting, anemia, leukocytopenia and alopecia, etc., and most of them were reversible. However, there were 2 patients in which the continuation of chemotherapy was impossible due to renal disorders.