First Case of Pyogenic Spondylodiscitis Caused by Gemella sanguinis

A 78-year-old man presented with back pain. Magnetic resonance imaging revealed marrow edema within the L4 and L5 vertebral bodies and a spinal epidural abscess in the spinal canal. The patient was considered to have pyogenic spondylodiscitis at the L4/L5 level. The Gram-positive cocci isolated from blood cultures were subsequently identified as Gemellasanguinis using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Symptom improvement was achieved and the infection was eradicated with conservative treatment (treatment with ceftriaxone [CTRX] and minocycline [MINO]). We report the first case of G. sanguinis-associated pyogenic spondylodiscitis. MALDI-TOF MS was useful in identifying this uncommon bacterium.

Pectin limits epithelial barrier disruption by Citrobacter rodentium through anti-microbial effects

SCOPE

C. rodentium is the murine equivalent of Enteropathogenic Escherichia. coli (EPEC) and Enterohemorrhagic Escherichia coli (EHEC) which induce damage to the intestinal epithelial barrier that results in diarrhea and intestinal inflammation. Dietary fibre intake can be an effective approach to limit epithelial damage by these enteric pathogens. Therefore, the protective effect of dietary fibre pectin against dysfunction of epithelial barrier integrity upon C. rodentium infection was investigated.

METHODS AND RESULTS

Pectins that structurally differed in the degree and distribution of methylesters were tested on barrier protective effects on epithelial cells against C. rodentium by measuring transepithelial electrical resistance and lucifer yellow fluxes. All three pectins protected the epithelial barrier from C. rodentium induced damage in a structure-independent manner. These barrier protective effects were also independent of pectin-induced TLR2 activation. Furthermore, the pectins induced anti-adhesive effects on C. rodentium by interacting with C. rodentium and not with epithelial cells. This may be explained by antimicrobial effects of pectins on C. rodentium and not on other enteric bacteria including Lactobacillus plantarum and E. coli. A competition ELISA for binding of C. rodentium to pectin supported this finding as it showed that pectin interacts strongly with C. rodentium, whereas it interacts weakly or not with L. plantarum or E. coli.

CONCLUSION

These findings demonstrate that pectin protects the epithelial barrier from C. rodentium induced damage by inducing anti-microbial effects.

Combined effect of teriparatide and an anti-RANKL monoclonal antibody on bone defect regeneration in mice with glucocorticoid-induced osteoporosis

OBJECTIVE

The purpose of this study was to examine the effect of single or combination therapy of teriparatide (TPTD) and a monoclonal antibody against the murine receptor activator of nuclear factor κB ligand (anti-RANKL Ab) on cancellous and cortical bone regeneration in a mouse model of glucocorticoid-induced osteoporosis (GIOP).

METHODS

C57BL/6 J mice (24 weeks of age) were divided into five groups: (1) the SHAM group: sham operation + saline; (2) the prednisolone (PSL) group: PSL + saline; (3) the TPTD group: PSL + TPTD; (4) the Ab group: PSL + anti-RANKL Ab; and (5) the COMB group: PSL + TPTD + anti-RANKL Ab (n = 8 per group). With the exception of the SHAM group, 7.5 mg of PSL was inserted subcutaneously into mice, to generate a mouse model of GIOP. Four weeks after insertion, bone defects with a diameter of 0.9 mm were created to assess bone regeneration on both femoral metaphysis (cancellous bone) and diaphysis (cortical bone). After surgery, therapeutic intervention was continued for 4 weeks. Saline (200 μl) or TPTD (40 μg/kg) was injected subcutaneously five times per week, whereas the anti-RANKL Ab (5 mg/kg) was injected subcutaneously once on the day after surgery. Subsequently, the following analyses were performed: microstructural assessment of bone regeneration and bone mineral density (BMD) measurement via micro-computed tomography, and histological, histomorphometrical, and biomechanical analyses with nanoindentation.

RESULTS

The COMB group showed the highest lumbar spine BMD increase (vs. the PSL, TPTD, and Ab groups). The volume of regenerated cancellous bone at the bone defect site was higher in the COMB group compared with the PSL, TPTD, and Ab group. The volume of the regenerated cortical bone was significantly higher in the COMB group compared with the PSL group, and its hardness was significantly higher in the COMB group compared with the PSL and TPTD groups.

CONCLUSION

In a mouse model of glucocorticoid-induced osteoporosis, the combination therapy of TPTD plus the anti-RANKL Ab increased bone mineral density in the lumbar spine and regenerated cancellous bone volume compared with single administration of each agent, and also increased regenerated cortical bone strength compared with single administration of TPTD.

Comparison in the same intervertebral space between titanium-coated and uncoated PEEK cages in lumbar interbody fusion surgery

BACKGROUNDS

Disadvantages of polyetheretherketone (PEEK) cages are their smooth and hydrophobic surfaces and their lack of osteoconductivity. Titanium (Ti) coated PEEK cage has been innovated to overcome these potential concerns. However, few well-designed studies have investigated the efficacy of Ti-coated PEEK cage on interbody fusion in humans. This study aimed to evaluate the efficacy of Ti coating on bone ongrowth at bone-implant surface by simultaneously comparing Ti-coated and uncoated PEEK cages in the same intervertebral space.

METHODS

This study is a prospective comparative study for the two different cages. Twenty-six subjects who underwent one-level instrumented posterior lumbar interbody fusion (PLIF) were included. Two PEEK cages [a plasma-sprayed Ti-coated (PTC-PEEK) and an uncoated PEEK cage] were inserted in the same intervertebral space. Fusion rates, cage subsidence, and vertebral cancellous condensation (VCC) around the cage, which indicates bone growth on the surface of each cage, were assessed by thin-slice computed tomography (CT) immediately (within 1 week) and at 3 months postoperatively. A functional radiograph was obtained at 3 and 12 months postoperatively.

RESULTS

Twenty-three subjects showed solid fusion at 3 months postoperatively (fusion rate, 88%). Cage subsidence was not observed. VCC was often observed around the PTC-PEEK cage as evaluated by completely synchronized CT images between immediately and at 3 months postoperatively. Quantified VCC around the cage was significantly larger in the PTC-PEEK cage than in the uncoated PEEK cage (P = 0.01).

CONCLUSIONS

The Ti-coated PEEK cage exhibits radiographic signs, suggesting bone ongrowth, as represented by VCC around the cage compared with that around the uncoated PEEK cage. The Ti-coated PEEK cage has the potential to promote solid fusion and to improve clinical outcomes in lumbar interbody fusion surgery.

Romosozumab was not effective in preventing multiple spontaneous clinical vertebral fractures after denosumab discontinuation: A case report

Discontinuation of denosumab is associated with the increase of bone turnover markers to above-baseline levels (so-called rebound in bone turnover) and rapid bone loss. Several studies have reported vertebral fractures (VFs), particularly multiple spontaneous clinical VFs (MSCVFs), occurring after discontinuation of denosumab. There is currently no recommendation for the management of VFs including MSCVFs. Presently, romosozumab is the strongest anti-osteoporotic agent that inhibits sclerostin and rapidly increases bone mass, but it is uncertain that romosozumab is an effective treatment choice to treat VFs occurring after discontinuation of denosumab. Herein we reported a novel case of a 60-year-old woman who was treated with romosozumab after discontinuation of denosumab and subsequently suffered MSCVFs under romosozumab treatment. She had a history of two osteoporotic VFs (T6 and T8) and received five doses of 60 mg denosumab every 6 months following the osteoporosis diagnosis. As per the patient's convenience, the sixth denosumab injection was postponed. To improve the persistent low bone mass in the lumbar spine (T-score −3.8), 210 mg romosozumab was administered monthly after 9 months following the last denosumab injection. At the first romosozumab injection, she had no clinical symptoms such as low back pain, but her bone formation and resorption marker levels elevated compared with those treated with denosumab. After three doses of romosozumab, spontaneous severe low back pain occurred, and time-course radiographs revealed five new VFs (T12, L2, L3, L4, and L5). Romosozumab administration had no suppressive effect on bone resorption during the rebound in bone turnover after discontinuation of denosumab. This case suggests that romosozumab is not effective in preventing VFs or MSCVFs after denosumab discontinuation.

Assessment of effects of rhBMP-2 on interbody fusion with a novel rat model

BACKGROUND CONTEXT

The effects of using off-label recombinant human bone morphogenetic protein (rhBMP)-2 for interbody fusion are controversial. Although animal models of posterolateral fusion are well-established, establishing animal models to validate the safety and efficacy of interbody fusion is difficult, which may contribute to the inconsistent clinical results.

PURPOSE

To develop a novel animal model of interbody fusion in rat coccygeal vertebrae without destroying bony endplates.

STUDY DESIGN

An experimental animal study.

METHODS

Forty-five male Sprague-Dawley rats underwent coccygeal interbody fusion without violating vertebral endplates. The animals were divided into three different groups based on the materials that were implanted into the interbody space (1) allogeneic iliac bone (IB) alone (IB group), (2) IB and 3 µg of rhBMP-2 (BMP low-dose group), or (3) IB and 10 µg of rhBMP-2 (BMP high-dose group). Fusion rates were investigated using microcomputed tomography 6 weeks after the operation. The incidence of adverse events, including soft-tissue swelling, delayed wound healing, osteolysis, and ectopic bone formation were evaluated. The total number of adverse events (using the adverse event score) in each group and the swelling ratio (calculated using the surgical site tissue volume [TV; TV on postoperative day 1/preoperative TV]) were also evaluated.

RESULTS

The fusion rates in the BMP low- and high-dose groups (33.3% and 46.7%) were not significantly different, but both were significantly higher than that in the IB group (0%) (p=.042 and .006, respectively). Significant differences in the incidence of osteolysis, adverse event scores, and swelling ratios were observed only between the BMP high-dose and IB groups (p=.043, .006 and .014, respectively).

CONCLUSIONS

We developed a novel rat model of interbody fusion in which the vertebral endplates were not violated, reflecting the normal clinical setting. rhBMP-2 use increased the fusion rate, but a higher dose of rhBMP-2 did not lead to a higher fusion rate than that for low-dose rhBMP-2; conversely, it led to an increase in the occurrence of adverse events.

CLINICAL SIGNIFICANCE

This novel rat model of coccygeal interbody fusion that preserved bony endplates has clinical significance for validating the effectiveness of biologics or bone graft substitutes before clinical trial.

The combined effects of teriparatide and anti-RANKL monoclonal antibody on bone defect regeneration in ovariectomized mice

OBJECTIVE

The purpose of this study was to investigate the combined effects of teriparatide (TPTD) and anti-murine receptor activator of nuclear factor-κB ligand monoclonal antibody (anti-RANKL Ab) on both cancellous and cortical bone healing in ovariectomized mice.

METHODS

Thirteen-week-old mice were divided into the sham-operated group (n=11) or the ovariectomized group (n=44). At 1 month post-operation, all mice underwent bone defect surgery on the left femoral metaphysis (cancellous bone healing model) and right femoral mid-diaphysis (cortical bone healing model). After creating the bone defects, all ovariectomized mice were assigned to one of four groups to receive 1) saline (5 times a week; CNT group), 2) TPTD (40μg/kg 5 times a week; TPTD group), 3) anti-RANKL Ab (5mg/kg once; Ab group), or 4) a combination of TPTD and anti-RANKL Ab (COMB group). The following analyses were performed: Time-course microstructural analysis of healing in both cancellous and cortical bone in the bone defect, measuring the volumetric bone mineral density and the cortical bone thickness of the tibia as a representative of whole body bone with the use of micro-computed tomography, and histological analysis.

RESULTS

Regeneration of cancellous bone volume in the COMB group was the highest among the four groups, and combined treatment accelerated the formation of medullary callus during the early phase of bone regeneration. On the other hand, there were no significant differences in the regeneration of cortical bone volume during the early phase of bone regeneration among the four groups. Furthermore, lamellar bone was not well identified in the all four groups. Volumetric bone mineral density in the tibia in the COMB group was significantly higher compared with that in the CNT and TPTD groups and tended to be higher compared with that in the Ab group. The mean values of cortical bone thickness in the TPTD and COMB groups were significantly higher than that in the CNT group.

CONCLUSION

In a mouse model of postmenopausal osteoporosis, combination therapy of TPTD and anti-RANKL Ab accelerates regeneration of cancellous bone more effectively than either agent alone during the early phase of bone regeneration.

Effects of Weekly Teriparatide Administration for Vertebral Stability and Bony Union in Patients with Acute Osteoporotic Vertebral Fractures

Study Design

An open-label, non-randomized prospective study.

Purpose

Teriparatide (TPTD) is known to be an antiosteoporotic agent that may accelerate the healing of fractures. This study was designed to investigate the effect of once-weekly TPTD administration on vertebral stability and bony union after acute osteoporotic vertebral fracture (OVF).

Overview of Literature

Once-weekly TPTD administration can lead to early vertebral stability and promote bony union of fractured vertebrae in patients with severe osteoporosis.

Methods

Forty-eight subjects with acute OVF were assigned to receive activated vitamin D3 and calcium supplementation or onceweekly subcutaneous injection of TPTD (56.5 μg) in combination with activated vitamin D3 and calcium supplementation for 12 weeks. Vertebral stability was assessed using lateral plain radiography. Vertebral height at the anterior location (VHa) and the difference in VHa {ΔVHa=VHa (supine position)−VHa (weight-bearing position)} were measured at baseline and 12 weeks after starting treatment. Bony union was defined as the absence of a vertebral cleft or abnormal motion (ΔVHa >2 mm).

Results

Although not significant, ΔVHa, indicating vertebral stability, tended to be lower in the TPTD group at 12 weeks (p =0.17). As for subjects with severe osteoporosis, ΔVHa at 12 weeks was significantly lower in the TPTD group than in the control group (mean ΔVHa: control group, 3.1 mm (n=15); TPTD group, 1.4 mm (n=16); p =0.02). The rate of bony union was significantly higher in the TPTD group than in the control group (control group, 40%; TPTD group, 81%; p =0.03).

Conclusions

Once-weekly TPTD administration may facilitate early bony union after acute OVF accompanied by severe osteoporosis.

Assessment of the effects of switching oral bisphosphonates to denosumab or daily teriparatide in patients with rheumatoid arthritis

The aim of this observational, non-randomized study was to clarify the unknown effects of switching oral bisphosphonates (BPs) to denosumab (DMAb) or daily teriparatide (TPTD) in patients with rheumatoid arthritis (RA). The characteristics of the 194 female patients included in the study were 183 postmenopausal, age 65.9 years, lumbar spine (LS) T score -1.8, femoral neck (FN) T score -2.3, dose and rate of taking oral prednisolone (3.6 mg/day) 75.8%, and prior BP treatment duration 40.0 months. The patients were allocated to (1) the BP-continue group (n = 80), (2) the switch-to-DMAb group (n = 74), or (3) the switch-to-TPTD group (n = 40). After 18 months, the increase in bone mineral density (BMD) was significantly greater in the switch-to-DMAb group than in the BP-continue group (LS 5.2 vs 2.3%, P < 0.01; FN 3.8 vs 0.0%, P < 0.01) and in the switch-to-TPTD group than in the BP-continue group (LS 9.0 vs 2.3%, P < 0.001; FN 4.9 vs 0.0%, P < 0.01). Moreover, the switch-to-TPTD group showed a higher LS BMD (P < 0.05) and trabecular bone score (TBS) (2.1 vs -0.7%; P < 0.05) increase than the switch-to-DMAb group. Clinical fracture incidence during this period was 8.8% in the BP-continue group, 4.1% in the switch-to-DMAb group, and 2.5% in the switch-to-TPTD group. Both the switch-to-DMAb group and the switch-to-TPTD group showed significant increases in LS and FN BMD, and the switch-to-TPTD group showed a higher increase in TBS compared to the BP-continue group at 18 months. Switching BPs to DMAb or TPTD in female RA may provide some useful osteoporosis treatment options.

Effects of single or combination therapy of teriparatide and anti-RANKL monoclonal antibody on bone defect regeneration in mice

OBJECTIVE

The purpose of this study is to investigate the effects of a single or combination therapy of teriparatide (TPTD) and anti-RANKL Ab (anti-murine receptor activator of nuclear factor κB ligand monoclonal antibody) on the regeneration of both cancellous and cortical bone.

METHODS

Nine-week-old mice underwent bone defect surgery on the left femoral metaphysis (cancellous-bone healing model) and right femoral mid-diaphysis (cortical-bone healing model). After surgery, the mice were assigned to 1 of 4 groups to receive 1) saline (5 times a week; CNT group), 2) TPTD (40μg/kg 5 times a week; TPTD group), 3) anti-RANKL Ab (5mg/kg once; Ab group), or 4) a combination of TPTD and anti-RANKL Ab (COMB group). The following analyses were performed: Time-course microstructural analysis of healing in both cancellous and cortical bone in the bone defect, the volumetric bone mineral density of the tibia with micro-computed tomography, histological, histomorphometrical, and biomechanical analysis of regenerated bone.

RESULTS

Regeneration of cancellous bone volume in the COMB group was the highest among the 4 groups, and this combined administration prompted medullary callus formation in the early phase of bone regeneration. On the other hand, regeneration of cortical bone volume in the COMB group was significantly higher than in the Ab group and was almost same as in the TPTD group. Histological analysis showed remaining woven bones, cartilage matrix, and immature lamellar bone in the COMB and Ab groups. However, biomechanical analysis showed that hardness and Young's modulus of regenerated cortical bone in the COMB group was not lower than in both the CNT and TPTD groups. Volumetric bone mineral density in the tibia was significantly increased in the COMB group compared with the other 3 groups.

CONCLUSION

In the early phase of bone regeneration, the combination of TPTD and anti-RANKL Ab accelerates regeneration of cancellous bone in bone defects and increases cancellous bone mass in the tibia more effectively than either agent does individually, but these additive effects are not observed in the regeneration of cortical bone.

Comparison of the effects of denosumab between a native vitamin D combination and an active vitamin D combination in patients with postmenopausal osteoporosis

The aim of this 12-month, retrospective study was to compare the effects of denosumab (DMAb; 60 mg subcutaneously every 6 months) plus native vitamin D (VD) (cholecalciferol) combination therapy with DMAb plus active VD analog (alfacalcidol) combination therapy in patients with postmenopausal osteoporosis. Patients [N = 127; mean age 75.6 years (range 58-93 years); 28 treatment-naïve patients, 59 patients treated with oral bisphosphonate therapy, 40 patients treated with teriparatide daily] were allocated to either (1) the DMAb plus native VD group (n = 60; cholecalciferol, 10 μg, plus calcium, 610 mg/day; 13 treatment-naïve patients, 28 patients treated with oral bisphosphonate therapy, and 19 patients treated with teriparatide daily) or (2) the DMAb plus active VD group [n = 67; alfacalcidol, 0.8 ± 0.0 μg, plus calcium, 99.2 ± 8.5 mg/day; 15 treatment-naïve patients, 31 patients treated with oral bisphosphonate therapy, and 21 patients treated with teriparatide daily) on the basis of each physician's decision. Changes in bone mineral density (BMD), serum bone turnover marker levels, and fracture incidence were monitored every 6 months. There were no significant differences in baseline age, BMD, bone turnover marker levels, and prior treatments between the two groups. After 12 months, compared with the DMAb plus native VD group, the DMAb plus active VD group showed similar increases in the BMD of the lumbar spine (6.4% vs 6.5%) and total hip (3.3% vs 3.4%), but significantly greater increases in the BMD of the femoral neck (1.0% vs 4.9%, P < 0.001) and the distal part of the forearm (third of radius) (-0.8% vs 3.9%, P < 0.01). These tendencies were similar regardless of the differences in the prior treatments. The rates of decrease of bone turnover marker levels were similar for tartrate-resistant acid phosphatase isoform 5b (-49.0% vs -49.0%), procollagen type I N-terminal propeptide (-45.9% vs -49.3%), and undercarboxylated osteocalcin (-56.0  vs -66.5%), whereas serum intact parathyroid hormone levels were significantly lower in the DMAb plus active VD group (47.6 pg/mL vs 30.4 pg/mL, P < 0.001). The rate of hypocalcemia was 1.7% in the DMAb plus native VD group and 1.5% in the DMAb plus active VD group, and the rate of clinical fracture incidence was 8.3% in the DMAb plus native VD group and 4.5% in the DMAb plus active VD group, with no significant difference between the groups. DMAb with active VD combination therapy may be a more effective treatment option than DMAb with native VD combination therapy in terms of increasing BMD of the femoral neck and distal part of the forearm and also maintaining serum intact parathyroid hormone at lower levels.

Comparison of the effects of forefoot joint-preserving arthroplasty and resection-replacement arthroplasty on walking plantar pressure distribution and patient-based outcomes in patients with rheumatoid arthritis

Purpose

The purpose of this retrospective study is to clarify the difference in plantar pressure distribution during walking and related patient-based outcomes between forefoot joint-preserving arthroplasty and resection-replacement arthroplasty in patients with rheumatoid arthritis (RA).

Methods

Four groups of patients were recruited. Group1 included 22 feet of 11 healthy controls (age 48.6 years), Group2 included 36 feet of 28 RA patients with deformed non-operated feet (age 64.8 years, Disease activity score assessing 28 joints with CRP [DAS28-CRP] 2.3), Group3 included 27 feet of 20 RA patients with metatarsal head resection-replacement arthroplasty (age 60.7 years, post-operative duration 5.6 years, DAS28-CRP 2.4), and Group4 included 34 feet of 29 RA patients with metatarsophalangeal (MTP) joint-preserving arthroplasty (age 64.6 years, post-operative duration 3.2 years, DAS28-CRP 2.3). Patients were cross-sectionally examined by F-SCAN II to evaluate walking plantar pressure, and the self-administered foot evaluation questionnaire (SAFE-Q). Twenty joint-preserving arthroplasty feet were longitudinally examined at both pre- and post-operation.

Results

In the 1^st MTP joint, Group4 showed higher pressure distribution (13.7%) than Group2 (8.0%) and Group3 (6.7%) (P<0.001). In the 2^nd-3^rd MTP joint, Group4 showed lower pressure distribution (9.0%) than Group2 (14.5%) (P<0.001) and Group3 (11.5%) (P<0.05). On longitudinal analysis, Group4 showed increased 1^st MTP joint pressure (8.5% vs. 14.7%; P<0.001) and decreased 2^nd-3^rd MTP joint pressure (15.2% vs. 10.7%; P<0.01) distribution. In the SAFE-Q subscale scores, Group4 showed higher scores than Group3 in pain and pain-related scores (84.1 vs. 71.7; P<0.01) and in shoe-related scores (62.5 vs. 43.1; P<0.01).

Conclusions

Joint-preserving arthroplasty resulted in higher 1^st MTP joint and lower 2^nd-3^rd MTP joint pressures than resection-replacement arthroplasty, which were associated with better patient-based outcomes.

Oxygen ultra-fine bubbles water administration prevents bone loss of glucocorticoid-induced osteoporosis in mice by suppressing osteoclast differentiation

Oxygen ultra-fine bubbles (OUB) saline injection prevents bone loss of glucocorti\coid-induced osteoporosis in mice, and OUB inhibit osteoclastogenesis via RANK-TRAF6-c-Fos-NFATc1 signaling and RANK-p38 MAPK signaling in vitro.

INTRODUCTION

Ultra-fine bubbles (<200 nm in diameter) have several unique properties, and they are tested in various medical fields. The purpose of this study was to investigate the effects of oxygen ultra-fine bubbles (OUB) on glucocorticoid-induced osteoporosis (GIO) model mice.

METHODS

Prednisolone (PSL, 5 mg) was subcutaneously inserted in 6-month-old male C57BL/6J mice, and 200 μl of saline, OUB-diluted saline, or nitrogen ultra-fine bubbles (NUB)-diluted saline was intraperitoneally injected three times per week for 8 weeks the day after operations. Mice were divided into four groups; (1) control, sham-operation + saline; (2) GIO, PSL + saline; (3) GIO + OUB, PSL + OUB saline; (4) GIO + NUB, PSL + NUB saline. The effects of OUB on osteoblasts and osteoclasts were examined by serially diluted OUB medium in vitro.

RESULTS

Bone mass was significantly decreased in GIO [bone volume/total volume (%): control vs. GIO 12.6 vs. 7.9; p < 0.01] while significantly preserved in GIO + OUB (GIO vs. GIO + OUB 7.9 vs. 12.9; p < 0.05). In addition, tartrate-resistant acid phosphatase (TRAP)-positive cells in the distal femur [mean osteoclasts number/bone surface (mm^-1)] was significantly increased in GIO (control vs. GIO 6.8 vs. 11.6; p < 0.01) while suppressed in GIO + OUB (GIO vs. GIO + OUB 11.6 vs. 7.5; p < 0.01). NUB did not affect these parameters. In vitro experiments revealed that OUB significantly inhibited osteoclastogenesis by inhibiting RANK-TRAF6-c-Fos-NFATc1 signaling, RANK-p38 MAPK signaling, and TRAP/Cathepsin K/DC-STAMP mRNA expression in a concentration-dependent manner. OUB did not affect osteoblastogenesis in vitro.

CONCLUSIONS

OUB prevent bone loss in GIO mice by inhibiting osteoclastogenesis.

Modeling and remodeling effects of intermittent administration of teriparatide (parathyroid hormone 1-34) on bone morphogenetic protein-induced bone in a rat spinal fusion model

Background

Bone morphogenetic protein (BMP)-based tissue engineering has focused on inducing new bone efficiently. However, modeling and remodeling of BMP-induced bone have rarely been discussed. Teriparatide (parathyroid hormone [PTH] 1-34) administration initially increases markers of bone formation, followed by an increase in bone resorption markers. This unique activity would be expected to accelerate the modeling and remodeling of new BMP-induced bone.

Methods

Male Sprague-Dawley rats underwent posterolateral spinal fusion surgery and implantation of collagen sponge containing either 50 μg recombinant human (rh)BMP-2 or saline. PTH 1-34 (60 μg/kg, 3 times/week) or saline injections were continued from preoperative week 2 week to postoperative week 12. The volume and quality of newly formed bone were monitored by in vivo micro-computed tomography and analyses of bone histomorphometry and serum bone metabolism markers were conducted at postoperative week 12.

Results

Microstructural indices of the newly formed bone were significantly improved by PTH 1-34 administration, which significantly decreased the tissue volumes of the fusion mass at postoperative week 12 compared to that at postoperative week 2. Bone histomorphometry and serum analyses showed that PTH administration significantly increased both bone formation and resorption markers. Analysis of the histomorphometry of cortical bone identified predominant periosteal bone resorption and endosteal bone formation.

Conclusions

Long-term intermittent administration of PTH 1-34 significantly accelerated the modeling and remodeling of new BMP-induced bone.

Clinical relevance

Our results suggest that the combined administration of rhBMP-2 and PTH 1-34 facilitates qualitative and quantitative improvements in bone regeneration, by accelerating bone modeling and remodeling.

•

The present study found that intermittent administration of PTH 1-34 significantly decreased the TV of new rhBMP-2-induced bone, following the initial formation of a fusion mass equivalent to that of the control group.

•

Bone histomorphometry demonstrated predominant bone resorption at the periosteum and bone formation at the endosteum in rats receiving PTH 1-34.

•

These results indicated that PTH 1-34 supported modeling of rhBMP-2-induced bone in addition to the remodeling effect which confirmed by bone histomorphometry and serum markers.

Progranulin plays crucial roles in preserving bone mass by inhibiting TNF-α-induced osteoclastogenesis and promoting osteoblastic differentiation in mice

A close correlation between atherosclerosis, inflammation, and osteoporosis has been recognized, although the precise mechanism remains unclear. The growth factor progranulin (PGRN) is expressed in various cells such as macrophages, leukocytes, and chondrocytes. PGRN plays critical roles in a variety of diseases, such as atherosclerosis and arthritis by inhibiting Tumor Necrosis Factor-α (TNF-α) signaling. The purpose of this study was to investigate the effect of PGRN on bone metabolism. Forty-eight-week old female homozygous PGRN knockout mice (PGRN-KO) (n = 8) demonstrated severe low bone mass in the distal femur compared to age- and sex-matched wild type C57BL/6J mice (WT) (n = 8) [BV/TV (%): 5.8 vs. 16.6; p < 0.001, trabecular number (1/mm): 1.6 vs. 3.8; p < 0.001]. In vitro, PGRN inhibited TNF-α-induced osteoclastogenesis from spleen cells of PGRN-KO mice. Moreover, PGRN significantly promoted ALP activity, osteoblast-related mRNA (ALP, osteocalcin) expression in a dose-dependent manner and up-regulated osteoblastic differentiation by down-regulating phosphorylation of ERK1/2 in mouse calvarial cells. In conclusion, PGRN may be a promising treatment target for both atherosclerosis and inflammation-related osteoporosis.

Higher incorporation of heterologous chicken immunoglobulin Y compared with homologous quail immunoglobulin Y into egg yolks of Japanese quail (Coturnix japonica)

In avian species, blood IgY is selectively incorporated into the yolks of maturing oocytes, although the precise mechanism is poorly understood. Our previous study showed that 22% of i.v.-injected heterologous chicken IgY (cIgY) was incorporated into egg yolks of Japanese quail (Coturnix japonica). However, it is not known whether homologous quail IgY (qIgY) can be more efficiently incorporated into quail egg yolks than cIgY. Therefore, we compared the uptakes of qIgY and cIgY i.v. administered into quail egg yolks and further characterized the uptakes of these 2 antibodies into quail ovarian follicles. Quail IgY and cIgY purified from the blood of the respective bird were labeled with digoxigenin, and their uptakes into quail egg yolks were determined by ELISA. Unexpectedly, total incorporation of the injected qIgY was only one-third of that of cIgY, although much more qIgY was left in blood compared with cIgY, suggesting that qIgY is the less preferable antibody as a transport ligand into quail egg yolks. On the other hand, deposition of the qIgY into heart, lung, liver, spleen, kidney, and ovarian follicular membrane was markedly higher than that of cIgY. Amino acid sequence analysis of 3 peptides derived from the trypsin-digested qIgY heavy chain revealed low homology between qIgY and cIgY. In conclusion, our results show that heterologous cIgY is more efficiently incorporated into quail egg yolks than homologous qIgY, possibly due to a distinctive antibody transport system existing in oocytes. The present results also may provide a new strategy for delivering useful proteinaceous substances into egg yolks in an attempt to produce designer eggs.

Inclusion of epinephrine to hyperbaric tetracaine and the supine position enhance the cephalad spread of spinal anaesthesia compared with hyperbaric teracaine alone in the lithotomy position

BACKGROUND

Intrathecal epinephrine can produce prolongation of duration of spinal anaesthesia by reducing vascular absorption of the local anaesthetics. The patient's positioning can change the cephalad spread of hyperbaric local anaesthetics by affecting the lordosis of the vertebral canal. These factors combined are expected to affect the cephalad spread of sensory block levels. The purpose of this study was to investigate whether combined use of epinephrine with hyperbaric tetracaine in the supine position can enhance the cephalad spread of sensory block levels compared with hyperbaric tetracaine alone in the lithotomy position.

METHODS

ASA physical status I or II 48 urological (lithotomy group) and 48 orthopaedic patients (supine group) scheduled to undergo elective surgical procedures in the lithotomy or supine position under spinal anaesthesia were enrolled. Patients in each group were randomly divided into two subgroups to receive intrathecal 10 mg of hyperbaric tetracaine with or without 0.2 mg of epinephrine (Groups L, LE, S, and SE). The extent of sensory blockade was assessed by loss of cold sensation. After achievement of sensory blockade up to T10, the patients in Groups L and LE were immediately placed in the lithotomy position. Patients in Groups S and SE were maintained in the supine position.

RESULTS

The highest sensory blockade in the SE Group was on average statistically significantly higher than in the L Group. The mean time taken to the highest sensory blockade in the SE Group was statistically significantly longer than in Groups L and S. Atropine for bradycardia was used more frequently in the SE Group than in the other groups.

CONCLUSIONS

Combined use of epinephrine with hyperbaric tetracaine in the supine position can enhance the cephalad spread of sensory block levels compared with hyperbaric tetracaine alone in the lithotomy position.

Double lumen tube location predicts tube malposition and hypoxaemia during one lung ventilation

BACKGROUND

Poor positioning of an endobronchial double lumen tube (DLT) could affect oxygenation during one lung ventilation (OLV). We set out to relate DLT position to hypoxaemia and DLT misplacement during OLV.

METHODS

We recruited 152 ASA physical status I-II patients about to have elective thoracic surgery. The trachea was intubated with a left-sided DLT. Tube position was assessed by fibre-optic scope and correction was made after patient positioning and during OLV. If Pa(O(2)) was less than 10.7 kPa, the DLT position was checked and then PEEP, continuous positive airway pressure (CPAP), oxygen insufflation, or two lung ventilation (TLV) were tried.

RESULTS

The DLT was found to be misplaced in 49 patients (32%) after patient positioning, and in 38 patients (25%) during OLV. PEEP to the dependent lung, CPAP or apneic oxygen insufflation to the non-dependent lung, or brief periods of TLV, were applied in 46 patients (30%). Patients who had DLT malposition after placing the patient in the lateral position had a greater incidence of DLT malposition during OLV (59 vs 9%) and also required each intervention more frequently (57 vs 10%). Patients with DLT malposition during OLV also required interventions more often (84 vs 12%).

CONCLUSIONS

Patients who have DLT malposition after placing the patient in the lateral position had more DLT malposition during OLV and hypoxaemia during OLV.

Plasma propofol concentration and EEG burst suppression ratio during normothermic cardiopulmonary bypass

BACKGROUND

During cardiopulmonary bypass (CPB), several factors affect drug disposition and action. This topic has not been studied extensively during normothermic CPB. In this study, we related propofol dose to plasma propofol concentration and burst suppression of the EEG during normothermic bypass.

METHODS

After institutional approval and informed consent, 45 patients having cardiac surgery were assigned randomly to receive propofol infusions at 4 (Group A), 5 (Group B) and 6 (Group C) mg kg(-1) h(-1) during normothermic CPB. In all patients, small to moderate doses of fentanyl were also administered. Plasma propofol concentration and burst suppression ratio (BSR) were measured at the following times: (1) 10 min before CPB, (2) 10 min after the start of CPB, (3) 30 min after the start of the CPB, (4) just after aortic declamping, and (5) 60 min after CPB.

RESULTS

At baseline, plasma propofol concentrations were similar among the three groups. After the start of CPB, the concentrations of propofol decreased significantly by 41, 35, and 30% of control values in Groups A, B, and C, respectively. In Group A, the concentration of propofol during CPB remained unchanged at less than the concentration before bypass. In Groups B and C, plasma propofol concentrations gradually increased during CPB to the pre-bypass concentrations. In Group A, BSR values did not change significantly during CPB. In Groups B and C, BSR values gradually increased and became significantly greater than baseline values. No patient reported intraoperative awareness.

CONCLUSION

The pharmacokinetics and pharmacodynamics of propofol change during normothermic CPB. During normothermic CPB, the efficacy of propofol may be enhanced compared with before CPB.

Comparison of the effects of sevoflurane and propofol on cooling and rewarming during deliberate mild hypothermia for neurosurgery

BACKGROUND

Because the time available for cooling and rewarming during deliberate mild hypothermia is limited, studies of the rate of the cooling and rewarming are useful. The decrease in core hypothermia caused by heat redistribution depends on the anaesthetic agent used. We therefore investigated possible differences between sevoflurane and propofol on the decrease and recovery of core temperature during deliberate mild hypothermia for neurosurgery.

METHODS

After institutional approval and informed consent, 26 patients were assigned randomly to maintenance of anaesthesia with propofol or sevoflurane. Patients in the propofol group (n=13) received propofol induction followed by a continuous infusion of propofol 3-5 mg kg(-1) h(-1). Patients in the sevoflurane group (n=13) received propofol induction followed by sevoflurane 1-2%. Nitrous oxide and fentanyl were also used for anaesthetic maintenance. After induction of anaesthesia, patients were cooled and tympanic membrane temperature was maintained at 34.5 degrees C. After surgery, patients were actively rewarmed.

RESULTS

There was no difference in the rate of decrease and recovery of core temperature between the groups. There was also no difference in skin surface temperature gradient (forearm to fingertip), heart rate and mean arterial blood pressure between the groups.

CONCLUSIONS

Sevoflurane-based anaesthesia did not affect cooling and rewarming for deliberate mild hypothermia compared with propofol-based anaesthesia.

Long-term retention of motor skill in macaque monkeys and humans

Remarkable human performance, such as playing the violin, is often based on motor skills that, once acquired, are retained for a long time. To examine how motor skills are retained, we trained monkeys and humans extensively to perform many visuomotor sequences and examined their performance after a long retention period of up to 18 months. For both monkeys and humans, we found strong evidence for long-term retention of motor skills. Each of the monkey subjects initially learned 6-18 sequences of button presses extensively by trial-and-error for up to 18 months. After a long retention period, they were asked to perform the previously learned (OLD) sequences together with completely new (NEW) sequences. The performance for OLD sequences was much better than for NEW sequences in terms of accuracy (assessed by the number of errors to criterion) and speed (assessed by the performance time). However, the retention was interfered with in two conditions, but in selective manners: (1) Learning of other sequences during the retention period interfered with accuracy, but not speed, of performance; (2) Inter-manual transfer was absent for speed, but not accuracy, of performance. The human subjects performed basically the same task as the monkeys. Each subject initially learned one sequence of 20 button presses by trial-and-error during an 8-10 day learning session. After 16 months, they were asked to perform the previously learned sequence (OLD sequence) and additional sequences including RECENT sequences (learned one day before) and NEW sequences. Their performance was considerably better on OLD and RECENT sequences than NEW sequences. Whereas the number of errors (reflecting 'accuracy') was lower for RECENT than for OLD sequences, the performance time (reflecting 'speed') was shorter for OLD than for RECENT sequences. Interestingly, the subjects were unaware that they had experienced OLD sequences. The results suggest that a motor skill is acquired and retained in two different forms, accuracy and speed. This occurs separately but concurrently. This conclusion is consistent with the hypothesis that at least two neural mechanisms operate independently to represent a motor skill.

Effect of mild hypothermia on nicorandil-induced vasodilation of pial arterioles in cats

OBJECTIVE

Nicorandil is characterized as hybrid between nitrates and potassium channel activators. Recent evidence suggested that mild hypothermia may alter cerebral vasodilation induced by a nitrate agent and potassium channel opener. However, the effect of mild hypothermia on nicorandil-induced vasodilation is not known. The present study was conducted to investigate whether mild hypothermia could alter nicorandil-induced cerebral vasodilation. In addition, the effects of mild hypothermia on cerebral vasodilation induced by nitroglycerin, a nitrate agent, and cromakalim, a selective adenosine 5'-triphosphate-sensitive potassium channel opener, were assessed in the same model.

DESIGN

Prospective, randomized, experimental study with repeated measures.

SETTING

Investigational animal laboratory.

SUBJECTS

Twenty-four cats.

INTERVENTIONS

Animals were anesthetized with pentobarbital. The cranial window technique, combined with microscopic video recording, was used to measure small (50-100 microm) and large (100-200 microm) pial arteriolar diameter in an experiment. Animals were assigned randomly to either a normothermic (37 degrees C) or a hypothermic (33 degrees C) group. Nicorandil, nitroglycerin, or cromakalim at concentrations of 10(-8), 10(-6), or 10(-4) mol/L was applied topically in the cranial window, and the diameter of pial arterioles was measured.

MEASUREMENTS AND MAIN RESULTS

Topical administration of nicorandil, nitroglycerin, and cromakalim significantly dilated both small and large pial arterioles in a dose-dependent manner during normothermia. Nicorandil-induced vasodilation of either large or small pial arterioles was not affected by hypothermia. However, hypothermia significantly attenuated nitroglycerine-induced vasodilation in both large and small pial arterioles and enhanced cromakalim-induced vasodilation in both large and small pial arterioles.

CONCLUSIONS

Nicorandil-induced vasodilation of cerebral pial arterioles was not affected by mild hypothermia. By contrast, mild hypothermia significantly attenuated nitroglycerin-induced vasodilation and enhanced cromakalim-induced vasodilation.

[Intraoperative unilateral changes in myogenic motor evoked potentials in patients undergoing thoracic aortic surgery]

Motor evoked potentials (MEPs) can be employed for monitoring the functional integrity of the descending motor pathways during thoracic aortic surgery. Since MEPs can be affected by a variety of intraoperative factors, intraoperative MEP changes have to be carefully interpreted. In this report, we describe two patients undergoing thoracic aortic surgery, in whom MEPs from the unilateral lower limb disappeared after femoral artery cannulation, and MEPs' recovered by modifying the position or removing the cannula. MEPs in the contralateral side remained unchanged. Neither patients showed postoperative neurologic dysfunction in the lower limbs. These observations suggest that regional ischemia of the lower limbs caused by femoral artery cannulation can affect intraoperative MEP finding.

[A case of awareness during propofol anesthesia using bispectral index as an indicator of hypnotic effect]

A 77-year old, woman weighing 44 kg with mild liver dysfunction underwent lower abdominal surgery. Anesthesia was induced with propofol 60 mg and fentanyl 0.1 mg. Tracheal intubation was facilitated with vecuronium 8 mg, and the lungs were ventilated with 33% oxygen in air. The bispectral index (BIS) was continuously monitored. Anesthesia was maintained with propofol infusion and analgesia was provided by thoracic epidural infusion of lidocaine 1.5%. The infusion rate of propofol was altered to maintain the BIS value between 40 and 50. The patient was hemodynamically stable with propofol 1.5 mg.kg-1.hr-1 and the BIS value was maintained about 40 during the operation. Near the end of the operation the patient moved suddenly. Suspecting inadequate anesthesia, a total of 40 mg of propofol i.v. and 5 ml of the epidural infusion were given. Immediately before the movement the BIS value was about 40. The operation was completed 30 min later. On discharge from the operating room the patient declared that she had been awake. She had heard voices and felt the surgeon working, but had suffered no pain. The BIS is a useful indicator for hypnotic effect, but this case demonstrates that awareness might occur even when BIS value indicates adequate hypnotic state.

[The memory of tracheal extubation during emergence from general anesthesia]

The authors evaluated the memory of tracheal extubation during emergence from general anesthesia. We screened 3,039 consecutive patients undergoing elective surgery from November 1, 1998 to December 31, 1999. Of 3,039 patients, 1,993 were interviewed postoperatively at the anesthesia clinic and 202 had the memory of tracheal extubation. The incidence was higher in the groups of female, younger and propofol anesthesia compared to male, elder and inhalational anesthesia, respectively. The patients who were dissatisfied with anesthesia were more in the patients with the memory of tracheal extubation compared to the patients without the memory. We consider that the memory of tracheal extubation contributes to the dissatisfaction with anesthesia.

The Association of High Jugular Bulb Venous Oxygen Saturation with Cognitive Decline After Hypothermic Cardiopulmonary Bypass

This study was conducted to investigate whether jugular bulb venous oxygen saturation (SjVO(2)) predicted cognitive decline after cardiac surgery with hypothermic cardiopulmonary bypass (CPB). We studied 35 patients undergoing cardiac surgery. After the induction of anesthesia, a 5.5F fiberoptic oximetry catheter was retrogradely inserted into the jugular bulb, and SjVO(2) and other cerebral oxygenation variables were analyzed before, during, and after CPB. At each point, an oxyhemoglobin dissociation curve was drawn, and the P(50) value of jugular bulb venous blood was calculated by computer analysis. Cognitive function was assessed with the revised version of Hasegawa's Dementia Scale and the Benton Revised Visual Retention Test before and early after the operation. In 15 patients (the Decline group), cognitive function was declined after surgery, whereas it remained unchanged in 20 patients (the Normal group). SjVO(2) was significantly higher and cerebral oxygen extraction was significantly lower before and during CPB in the Decline group than in the Normal group (P < 0.05). The oxygen pressure at an oxygen saturation of 50% was significantly lower before and after CPB in the Decline group than in the Normal group (P < 0.05). Logistic regression analysis showed that high SjVO(2) was a predictor of cognitive decline after cardiac surgery. We conclude that high SjVO(2) was associated with cognitive decline after cardiac surgery with hypothermic CPB.

IMPLICATIONS

Jugular bulb venous oxygen desaturation has been suggested as a predictor of cognitive decline after cardiac surgery. However, the clinical value of jugular bulb venous oxygen saturation (SjVO(2)) may be limited during hypothermic cardiopulmonary bypass (CPB) when oxygen affinity to hemoglobin is increased. This study shows that high SjVO(2) before and during hypothermic CPB is a predictor of subsequent cognitive decline.

[Propofol Concentration during Maintenance of and Emergence from Propofol/Epidural Anesthesia: Comparison between Younger and Elderly Patient]

To investigate the influence of patient age on the sensitivity to propofol, we measured blood propofol concentrations in ten elderly (over 70 years of age) and ten younger (under 60 years of age) patients undergoing elective abdominal surgery during propofol/epidural anesthesia. Bispectral index (BIS) was continuously recorded for monitoring anesthetic effect, and the infusion rate of propofol was controlled to keep BIS at 50 after the induction of anesthesia with propofol. At steady-state before skin incision, propofol concentrations to maintain BIS at 50 in younger and elderly patients were 4.3 +/- 1.6 micrograms.ml-1 and 3.2 +/- 1.3 micrograms.ml-1, respectively, and there was no significant difference. Mean blood propofol concentrations were 4.0 +/- 1.5 micrograms.ml-1 for the younger group and 3.2 +/- 1.7 micrograms.ml-1 for the elderly group at the end of surgery immediately before discontinuation of propofol, and they were 1.9 +/- 0.7 micrograms.ml-1 (BIS = 86 +/- 7) for the younger group and 1.5 +/- 0.8 micrograms.ml-1 (BIS = 84 +/- 3) for the elderly group at the time of eye opening with no significant difference. We found appreciable individual variations in the propofol concentrations both in younger and elderly patients in this study.

[Relationship between minimum alveolar concentration and electroencephalographic bispectral index as well as spectral edge frequency 95 during isoflurane/epidural or sevoflurane/epidural anesthesia]

To investigate the relationship between minimum alveolar concentration (MAC) and electroencephalographic variables, we measured the bispectral index (BIS) and the spectral edge frequency 95 (SEF 95) in 17 patients undergoing elective surgery during isoflurane/epidural (n = 8) or sevoflurane/epidural (n = 9) anesthesia. Patients received 2.0 MAC end-tidal concentrations of isoflurane or sevoflurane, and the BIS and the SEF 95 were recorded after 15 min of an unchanged end-tidal concentration. The concentration of the inhalational agent was decreased to 1.2 MAC, and measurements were repeated again. During isoflurane anesthesia, the BIS increased significantly (3.6 +/- 3.9 at 2.0 MAC, 43.5 +/- 9.2 at 1.2 MAC [mean +/- SD]). In contrast, the BIS did not change significantly during sevoflurane anesthesia (35.3 +/- 8.4 at 2.0 MAC, 42.8 +/- 6.1 at 1.2 MAC). There were significant differences in the BIS and the SEF 95 at 2.0 MAC between isoflurane and sevoflurane groups. In contrast, the BIS and the SEF 95 showed no difference at 1.2 MAC between the groups. These findings suggest that different inhalational anesthetics may have different effects on the BIS and the SEF 95.

[Anesthetic management of the King-Denborough syndrome]

The King-Denborough syndrome (KDS) is a congenital myopathy with musculoskeletal abnormalities, and definitely associated with susceptibility to malignant hyperthermia (MH). We present the first report in Japan concerning the management of a KDS patient. A 2-year-old boy was scheduled for cryptorchidopexy. He had some physical signs of KDS, e.g. pectus excavatum, low-set ears, malar hypoplasia, micrognathia, ptosis and down-slanting palpebral fissures. Moreover, his mother and maternal grand-uncle had medical history of MH. Therefore, he was diagnosed as KDS by pediatricians. All of the preoperative examinations, including serum creatine phosphokinase level, are normal. Previous 15 case-reports suggest that in KDS patients MH might be triggered by volatile anesthetics. To avoid the trigger, we maintained the general anesthesia with propofol, fentanyl and vecuronium. During perioperative period, his body temperature was 36.3-38.1 degrees C, and no symptom of MH was observed. It is rare that a diagnosis of KDS is made preoperatively since the MH-induction is involved in the criteria of this syndrome. In the anesthesia of patients who are suspected of KDS from their characteristic features or familial histories, an anesthesiologist should pay attention to prevent MH. The total intravenous anesthesia method appears useful for the management of KDS.

[Ketamine lollipop for pediatric premedication]

Lollipop containing ketamine (50 mg) was evaluated for the premedication of pediatric patients. The subject of this study were 12 children aged from 1 year 7 months to 6 years. They received the lollipop and showed relatively good emotional state and no typical side effects. These results suggest good possibility of ketamine lollipop as the premedication for pediatric patients.

[Assessment of anesthesia satisfaction using direct interviews at post-anesthesia clinic]

The authors studied 5,034 consecutive patients undergoing elective surgery. Preoperative, intraoperative, and postoperative variables were gathered and patient satisfaction was assessed using direct interviews at pre- and post-anesthesia clinic. Fifty-nine percent of the 4,717 responders showed satisfaction and 4% showed dissatisfaction with anesthesia. The most undesirable perioperative outcome was vomiting/nausea. Other undesirable outcomes include discomfort of urine catheter, sore throat, memory of extubation, postoperative pain and so on. Anesthesiologist can improve the quality of anesthesia by preoperative explanation and preventative management for undesirable perioperative outcomes.

[Effect of colforsin daropate hydrochloride after cardiopulmonary bypass]

We evaluated the effects of colforsin daropate hydrochloride (CDH) after cardiopulmonary bypass (CPB) in comparison with milrinone. CDH or milrinone were given during and after CPB combined with cathecholamines so as to maintain mean arterial pressure (mABP > 60 mmHg) and cardiac index (CI > 3.0 l.min-1.m-2). Hemodynamics measurement was done immediately after CPB (A 1), one hour after CPB (A 2) and after the chest closure (A 3). In CDH group, mABP was significantly higher compared with milrinone group. Also, CDH group showed a significant reduction in the cases of combined use of dobutamine (at A 2, A 3) and norepinephrine (at A 1, A 2) compared with milrinone group. In conclusion, colforsin daropate hydrochloride exerts more inotropic effect and could reduce the necessity of combined use of cathecholamine compared with milrinone.

[Two cases of ischemic changes indicated in the amplitude of motor evoked potentials during thoracoabdominal aortic aneurysm repair]

Monitoring of motor-evoked potentials (MEPs) is employed to examine functional integrity of descending motor pathway during thoracic aortic surgery. We experienced two cases of intraoperative changes in MEPs during thoracic aortic replacement. In one case, MEPs recovered after the intercostal artery reattachment, and in another case after the release of aortic clamping. No postoperative paraplegia was found in both cases. We conclude that monitoring of MEPs is useful not only because we can detect symptoms of the spinal cord injury from ischemia immediately but also because they give us a clue to decide operative procedures.

[Differences in hemodynamic effects of amrinone, milrinone and olprinon after cardiopulmonary bypass in valvular cardiac surgery]

The differences in hemodynamic effects of amrinone, milrinone and olprinone were evaluated in 46 patients for valvular cardiac surgery after cardiopulmonary bypass (CPB). Patients were randomly allocated to three groups; group A with amrinone infusion (17 patients); group M with milrinone infusion (15 patients); and group O with olprinone infusion (14 patients). Each drug was administrated as a single dose into the venous reservoir of the CPB circuit 15 min prior to the end of emergence from CPB, followed by continuous infusion. Hemodynamic parameters were measured at the time of preCPB (C0), just after the end of CPB (C1), one hour after the termination of CPB (C2) and after the chest closure (C3). Catecholamines were used in order of dopamine, norepinephrine and dobutamine. These doses were modulated to maintain the cardiac index > 3.0 l.min-1.m-2 by each anesthesiologist. Hemodynamic parameters (at C0, C1, C2 and C3) and the doses of cathecholamine (at C1, C2 and C3) were compared among the 3 drugs. The systolic blood pressure in group M was significantly higher than that of group A and group O after chest closure. In group M and A, the systolic blood pressure showed a significant increase after CPB. On the other hand, the systolic blood pressure showed no significant change in group O after CPB. Three drugs showed no significant difference in the dosages of catecholamines used.

Hypothermia attenuates the vasodilatory response of pial arterioles to hemorrhagic hypotension in the cat

We investigated the effect of hypothermia on the vasodilatory response of pial arterioles to hemorrhagic hypotension. The cranial window technique was combined with microscopic video recording in an experiment involving 20 cats anesthetized with pentobarbital. The animals were randomly assigned to either a normothermic or a hypothermic group (32 degrees C). Mean arterial pressure (MAP) was reduced in stepwise increments of 10 mm Hg (from 100 to 50 mm Hg) by blood withdrawal. The diameter of small (50-100 microm) and large (100-200 microm) pial arterioles was measured. In the normothermic group (n = 9), small and large arterioles dilated at a MAP of 60 and 50 mm Hg, and at a MAP of 70, 60, and 50 mm Hg, respectively, compared with baseline values obtained at a MAP of 100 mm Hg. In contrast, in the hypothermic group (n = 11), vasodilation of either small or large arterioles was absent. The percentage diameter of small and large arterioles (percentage of control) was significantly lower at a MAP of 70, 60, and 50 mm Hg in the hypothermic group than the normothermic group. Our in vivo study demonstrates that hypothermia impairs autoregulatory vasodilation of pial arterioles in response to hemorrhagic hypotension.

IMPLICATIONS

Deliberate mild hypothermia has been proposed as a means of providing cerebral protection during neurosurgical procedures. Our results suggest that cerebral blood flow autoregulation in response to hemorrhagic hypotension may be impaired during hypothermic conditions, indicating the importance of maintaining perfusion pressure during hypothermic therapy to prevent cerebral ischemia.

[Monitoring of motor evoked potentials during insertion of iliosacral screws for reconstruction of pelvic fracture in two patients]

Monitoring of myogenic motor evoked potentials (MEPs) induced by transcranial electrical stimulation has become a promising tool for intraoperative monitoring. We described 2 patients who had developed significant decrease in MEP during the insertion of iliosacral screws for reconstruction of pelvic fractures. In both patients, MEPs were successfully obtained prior to the insertion under general anesthesia and partial neuromuscular blockade (propofol, ketamine, fentanyl, and nitrous oxide in oxygen: vecuronium), but reduced in association with the insertion. In one patient, they were restored by the re-insertion of screw and no new neurological deficits were observed postoperatively. However, in another patient, the decrease was not normalized and he suffered from paresis of the lower extremities after the surgery. We consider that intraoperative changes in MEPs could precisely predict postoperative motor function.

[Relationship between changes in estimated and measured blood concentrations of propofol and serum albumin concentration during propofol anesthesia: effects of intraoperative bleeding (a case report)]

We investigated the effect of intraoperative bleeding on the changes in estimated and measured blood concentrations of propofol, and the relationship between anesthetic effect of propofol and serum albumin concentration in a patient undergoing prostatectomy during propofol/epidural anesthesia. The rate of propofol infusion was titrated to keep the BIS value about 50. The estimated blood concentration of propofol calculated by ConGrase, a program for on-line simulation of blood propofol concentration, was monitored during anesthesia. Blood samples were obtained at nine points during surgery and the blood concentrations of propofol and albumin were measured postoperatively. When the amount of bleeding reached about 2000 mg, the difference between estimated and measured blood concentrations of propofol did not increase. As the serum albumin concentration decreased, the concentration of propofol to keep bispectral index about 50 decreased. This study suggests that the change in serum albumin concentration following intraoperative bleeding is an important factor in the anesthetic effect of propofol.

Characteristics of sequential movements during early learning period in monkeys

We previously demonstrated that the organization of a learned sequential movement, after long-term practice, is based on the entire sequence and that the information pertaining to the sequence is largely specific to the hand used for practice. However, it remained unknown whether these characteristics are present from the beginning of learning. To answer the question, we examined the performance of four monkeys for the same sequential procedure in the early stage of learning. The monkeys' task was to press five consecutive pairs of buttons (which were illuminated), in a correct order for every pair, which they had to find by trial-and-error during a block of trials. We first examined whether the memory of a sequential procedure that was learned once was specific to the hand used for practice. The second time that the monkeys attempted to learn a novel sequence, they were required to use either the same hand they used the first time or the opposite hand. The number of errors decreased to a similar degree in the same-hand condition and in the opposite-hand condition. The performance time decreased in the same-hand condition, but not in the opposite-hand condition. The results suggest that, in the early stage of learning, memory of the correct performance of a sequential procedure is not specific to the hand originally used to perform the sequence (unlike the well-learned stage, where the transfer was incomplete), whereas memory of the fast performance of a sequential procedure is relatively specific to the hand used for practice (like the well-learned stage). We then examined whether memory of a sequential procedure depends on the entire sequence, not individual stimulus sets. For the second learning block, we had the monkey learn the sequence in the same or reversed order. In the reversed order, the order within each set was identical, but the order of sets was reversed. The number of errors decreased in both the same-order and reversed-order conditions to a similar degree for two out of four monkeys; the decrease was larger in the same-order condition for the other two monkeys. For all monkeys, the performance time decreased in the same-order condition, but not in the reversed-order condition. The results suggest that the memory structure for correct performance varies among monkeys in the early stage of learning (unlike the well-learned stage, where the memory of individual sets was consistently absent). On the other hand, memory of the fast performance of a sequential procedure is relatively specific to the learned order used for practice (like the well-learned stage).

[Intraoperative motor evoked potential monitoring: a review of 115 cases]

We reviewed our experiences of intraoperative motor evoked potentials (MEPs) monitoring for 115 operations on the spine or spinal cord. We observed compound muscle action potentials from bilateral anterior tibial muscles by electrical transcranial stimulation of the motor cortex under general anesthesia induced and maintained with intravenous anesthetics (ketamine, propofol, or droperidol), fentanyl, and 50% nitrous oxide. Partial neuromuscular blockade was obtained with continuous infusion of vecuronium. MEPs were recorded bilaterally in 91 cases (79%) and laterally in 18 cases (16%). Postoperative deterioration of motor function was observed in 2 cases and amplitude of MEPs decreased more than 50% of control values in both cases. Intraoperative monitoring of MEPs might be a reliable indicator of spinal cord motor function.

[Optimal dose of indocyanine-green injected from the peripheral vein in cardiac output measurement by pulse dye-densitometry]

Cardiac output is measured by pulse dye-densitometry using indocyanine-green (ICG). This cardiac output is estimated by correlating with the cardiac output measured by pulmonary artery catheter using thermodilution method. Twenty-four patients scheduled for elective cardiovascular surgeries under general anesthesia were studied. The pulse dye-densitometry monitoring system used was DDG-2001 (Nihon Kohden, Japan). In group A (13 patients: 19 times), ICG was administered from the peripheral vein as bolus doses of 5, 10 or 20 mg (5 mg.ml-1 water solution). In group B (11 patients: 12 times), ICG was administered from the peripheral vein as bolus doses of 20, 10 or 5 mg (5 mg.ml-1 water solution). The correlation (Pearson's correlation coefficient) and precision (the method proposed by Bland and Altman) compared with cardiac output measured by pulmonary artery catheter were examined. Better correlation and precision were recognized after 20 mg ICG injection than 5 or 10 mg ICG injection. In conclusion, the measurement of cardiac output by pulse dye-densitometry with peripheral vein ICG injection was useful using a bolus dose of ICG 20 mg.

[The effect of intraoperative mild hypothermia on the development of perioperative cardiac ischemia]

We evaluated the risk of perioperative cardiac ischemia associated with mild hypothermia as adjunct management for neurosurgical procedures. Forty-seven elective neurosurgical patients were randomly assigned to either hypothermic group (H, n = 24) or normothermic one (N, n = 23). Patients in group H were cooled to and maintained at 34.5 degrees C (tympanic membrane temperature) and rewarmed after main neurosurgical manipulation, while those in group N were kept in normothermic state. Cardiac ischemia was diagnosed with Holter electrocardiogram monitored for 24 hours after admission to the operating room. No differences were observed in demographic data including age, gender, weight, height, rate of having cardiac disease, anesthesia methods, and contents of surgery. Temperature was significantly lower in group H than N both at the lowest point (34.6 +/- 0.5 vs 35.9 +/- 0.6, mean +/- SD) and at the conclusion of anesthesia (35.9 +/- 0.9 vs 36.5 +/- 0.5). Electrocardiographic ST segmental depression was observed in 3 (group H) and 5 cases (group N), and postoperative shivering occurred in 3 (group H) and 2 cases (group N), respectively. Those incidences were not statistically significant (chi-square test, P was set at 0.05). We concluded that intraoperative mild hypothermia might not increase the risk of perioperative cardiac ischemia in patients for neurosurgical procedures.

[Effect of deliberate mild hypothermia on the incidence of surgical-wound infection and duration of hospitalization in neurosurgical patients]

We investigated the effect of mild hypothermia on the incidence of surgical-wound infection and duration of hospitalization, retrospectively. We randomly assigned 173 patients undergoing intracranial operation to mild hypothermic group (group H) of 122 patients or normothermic group (group N) of 51 patients. A water blanket and a convective device blanket were used for thermal control in the both groups. The temperature at the tympanic membrane was adjusted to 34.5 degrees C in group H and 36.0 degrees C in group N. Surgical-wound infection was found in 4 of 122 patients (3.3%) of group H but in none of 51 patients (0%) of group N. The duration of hospitalization was 36.0 +/- 25.5 days in group H and 40.2 +/- 36.9 days in group N. There were no statistical differences of the incidence of surgical-wound infection and duration of hospitalization between the two groups. However, the duration to suture removal was significantly longer in group H than in group N (8.3 +/- 1.6 vs 7.8 +/- 0.8 days). Although the effects of deliberate mild hypothermia for neurosurgery on the incidence of surgical-wound infection and duration of hospitalization were little, it may affect the recovery process of such patients.

The effect of sevoflurane on myogenic motor-evoked potentials induced by single and paired transcranial electrical stimulation of the motor cortex during nitrous oxide/ketamine/fentanyl anesthesia

To overcome anesthetic-induced depression of myogenic motor-evoked potentials (MEPs), several techniques of stimulation using paired pulses or trains of pulses are used. This study investigated the effect of sevoflurane on myogenic MEPs induced by single and paired transcranial electrical stimulation of the motor cortex. Nine patients undergoing elective spinal surgery were anesthetized with fentanyl-N2O-ketamine. Partial neuromuscular blockade (single-twitch height 15% of baseline) was maintained with vecuronium. Single and paired (interstimulus interval 2 milliseconds) electrical stimuli were delivered to the scalp, and compound muscle action potentials were recorded from the left and right tibialis anterior muscles. In all patients, baseline MEPs were recorded from both the left and right anterior tibialis muscles (in a total of 18 legs). During the administration of 0.25 MAC and 0.5 MAC sevoflurane, MEPs induced by stimulation with a single pulse could be recorded in 12 of 18 and 4 of 18 legs, respectively, and MEP amplitude was significantly reduced to 48% and 4% of the control value, respectively. During the administration of 0.75 MAC sevoflurane, MEPs following single-pulse stimulation could not be recorded in any legs. The success rate of MEP recording during the administration of sevoflurane was greater after paired stimulation than after single stimulation, and percentage MEP amplitude (percentage of the control value after single stimulation but before sevoflurane) after paired stimulation was significantly higher than after single stimulation before and during the administration of 0.25 MAC and 0.5 MAC sevoflurane. The success rate of MEP recording and MEP amplitude after paired stimulation decreased in a dose-dependent manner during the administration of sevoflurane. These results suggest that although facilitation by the second stimulus was considerable, paired stimuli are still not sufficient to overcome the depressant effects of sevoflurane in clinically used concentrations.

[Analysis of postoperative shivering following the deliberate mild hypothermia during neurosurgery]

We induced deliberate mild hypothermia in 96 patients who underwent intracranial operations using a water blanket and a convective device blanket. The lowest temperature measured at the tympanic membrane during mild hypothermia was adjusted to 34.5 degrees C. The patients were divided into two groups in respect to the occurrence of postoperative shivering, and the relationship between the perioperative parameters and the occurrence of postoperative shivering was evaluated. Shivering was observed postoperatively in 29 to 96 patients (30.2%). In the group with shivering (SV), age was significantly lower and body weight and body surface area were significantly larger than the group without shivering (NSV). Urinary output was significantly larger in SV than in NSV. Tympanic membrane, nasopharyngeal, and rectal temperatures at the end of surgery and nasopharyngeal, rectal, and peripheral temperatures just after the extubation were significantly lower in SV than in NSV. These results suggest that sufficient rewarming of both the core and peripheral temperatures is important to prevent the postoperative shivering following the mild hypothermic therapy in neurosurgical patients, especially in young patients.

Mild hypothermia can attenuate nitroglycerin-induced vasodilation of pial arterioles in the cat

The purpose of the present study was to investigate the effect of mild hypothermia on nitroglycerin-induced vasodilation of cerebral vessels. The cranial window technique, combined with microscopic video recording, was used in an experiment involving 26 cats anesthetized with isoflurane. Animals were randomly assigned to either a normothermic or a mildly hypothermic group (33 degrees C). We administered three different concentrations of nitroglycerin (10[-6], 10[-5], 10[-4] M) under the window and measured the diameter of small (< 100 microm) and large (100-200 microm) pial arterioles. In the normothermic group (n = 13), nitroglycerin produced a significant dilation of both small and large arterioles in a dose-dependent manner. In the hypothermic group (n = 13), a significant dilation of arterioles was observed only after topical application of nitroglycerin at a concentration of 10(-4) M. The percent increase in diameter of small and large arterioles was less in the hypothermic group than the normothermic group. Our in vivo study demonstrates that topically applied nitroglycerin produces a dose-dependent dilation of pial arterioles in normothermic cats anesthetized with isoflurane, but the reduction of temperature to 33 degrees C significantly attenuates nitroglycerin-induced vasodilation of pial arterioles.

IMPLICATIONS

Although nitroglycerin may be used in hypothermic patients, the effect of mild hypothermia on nitroglycerin-induced vasodilation of cerebral vessels is unknown. In this study, we investigated the effects of nitroglycerin on pial arteriolar diameter in normothermic and hyperthermic cats. Hypothermia was found to attenuate nitroglycerin-induced vasodilation.