Biomedical subjects

Yoichi Shimada

Publications and source records attributed to Yoichi Shimada.

At least 55 records · Page 3Linked to original sources

PubMed2004

Osteosarcoma occurring in osteogenesis imperfecta.

We describe a case history of a 24-year-old male with osteogenesis imperfecta (OI) who developed osteosarcoma of the left thigh. High-dose ifosfamide therapy caused marked tumor regression of multiple lung metastases. Immunohistochemically, the tumor cells were diffusely positive for the p53 protein. Mutation of the p53 gene was not detected by direct genomic sequencing of exons 4-8. The radiographic characteristics, including irregularly distributed osteolytic lesions and cortical discontinuity, should not be confused with hyperplastic callus formation, a benign process. A biopsy is critical to establish the differential diagnosis between osteosarcoma and common hyperplastic callus formation in OI; however, it must be applied with great care.

Adult↗

PubMed2004

Unanticipated hemothorax during general anesthesia.

We experienced a case of uncommon spontaneous hemothorax during general anesthesia. A 72-year-old woman underwent emergency repair of damaged ascending colon. Her chest roentgenogram before surgery revealed no abnormalities. After the uneventful surgery, the trachea was extubated and the patient breathed without difficulty with stable vital signs. However, the S(p)(O)(2) varied around 95% with a 100% oxygen mask. Chest roentgenogram obtained after extubation showed a massive amount of fluid in the pleural cavity. A chest drainage tube was inserted, and approximately 1000 ml of frank blood was drawn without air leakage. Thereafter, her oxygenation remarkably improved. We could not determine the etiology of the hemothorax.

Aged↗

PubMed2004

Ropivacaine produces sensory blockade in the lumbar sacral region more frequently than mepivacaine in lower thoracic epidural anesthesia.

PURPOSE: The first sacral nerve has the largest diameter among the spinal nerves and is resistant to local anesthetics. Ropivacaine is a newly developed local anesthetic. There is a possibility that a difference in chemical properties between ropivacaine and other local anesthetics produces a difference in the blockade of the S1 dermatome by lower thoracic epidural anesthesia. Mepivacaine, 2%, is frequently used for epidural anesthesia and produces a level of blockade similar to that of bupivacaine, 0.5%. The purpose of this study was to examine the sensory blockade in the sacral region induced by ropivacaine with that induced by mepivacaine administered in the lower thoracic epidural space. METHODS: Eighteen adults undergoing lower thoracic epidural anesthesia (thoracic 11/12 interspace) were studied in a double-blind fashion. Patients were assigned to one of two groups: those who received 2% mepivacaine, 18 ml (group M; n = 9), and those who received 1% ropivacaine, 12 ml (group R; n = 9). The cephalad levels of sensory blockade to cold, pinprick, and touch in the L2, S1, and S3 dermatomes were assessed at 10, 20, and 35 min after injection. RESULTS: There were no differences in the cephalad levels of sensory block to cold (T4 [range, T4-T2] and T4 [range, T6-T2]), pinprick (T4 [range, T6-T4] and T4 [range, T6-T4]), or touch (T6 [range, T6-T4] and T6 [range, T6-T4]) between group M and group R respectively, at 35 min (P > 0.05). In the L2 and S3 dermatomes, there were no significant differences in the numbers of patients who obtained sensory block to cold or pinprick at 20 and 35 min after study drug administration. However, in the S1 dermatome, significantly higher numbers of patients in group R obtained sensory block to cold at 20 and 35 min after study drug administration than in group M (8 and 0; 9 and 0; P = 0.001 and P < 0.001; 20 min and 35 min after administration, respectively). Also in the S1 dermatome, significantly higher numbers of patients in group R obtained sensory block to pinprick at 20 and 35 min after study drug administration than in group M (6 and 0; 9 and 0; P = 0.027 and P < 0.001; 20 min and 35 min after administration, respectively). A significantly higher number of patients in group R had sensory block to touch in the S3 dermatome at 35 min (7 and 2; group R and group M, respectively; P = 0.01). CONCLUSION: Ropivacaine, 1%, administered in the lower thoracic epidural space, induces sensory blockade to cold and pinprick in the S1 dermatome more frequently than 2% mepivacaine.

Adult↗

PubMed2004

Usefulness of posturography after epidural block.

After a nerve block, observation of the course of effects is necessary until discharge of patients. Particularly epidural block in the lumbar region markedly affects ambulation and postural stability. Although there are few methods of objective evaluation of the postural stability, safe and early discharge is desired. We evaluated the influences of epidural block with 5 ml of 1% lidocaine on equilibrium before as well as 30, 60 and 90 minutes after epidural block. Computerized posturography allows the objective evaluation and quantitative assessment of impairment of receptors and the central nervous system involved in the maintenance of postural stability by analyzing of results. Locus length per unit area with the eyes open and that with the eyes closed 30 minutes after epidural block (27.339 +/- 11.761 cm and 25.804 +/- 10.561 cm, respectively) were significantly (P = 0.0067 and 0.0175, respectively) higher than baseline values (19.528 +/- 8.240 cm and 19.496 +/- 7.450 cm, respectively). Sway area with the eyes open 30 minutes after epidural block (3.923 +/- 2.494 cm2) was significantly (P = 0.0190) larger than the baseline value (2.533 +/- 1.309 cm2). These results suggest that marked effect remain after epidural block even when standing appears to be stable, and the observation of the course of effects after epidural block is still necessary for the safety of patients. We considered that locus length per unit area is a useful parameter for the assessment of an early discharge.

Adult↗

PubMed2004

Effect of low-dose ketamine on redistribution hypothermia during spinal anesthesia sedated by propofol.

Mild hypothermia is a common complication during spinal anesthesia and may induce a serious adverse outcome. We investigated the effect of low-dose ketamine infusion on the core temperature during spinal anesthesia sedated by propofol infusion. Twenty patients who were scheduled to undergo spinal anesthesia were assigned to one of two groups: after intrathecal injection of bupivacaine, patients who received infusion of ketamine (0.3 mg/kg/hr) and propofol (initial rate of 10 mg/kg/hr) (KP group), and patients who received infusion of placebo (saline) and propofol (initial rate of 10 mg/kg/hr) (P group). The rate of propofol administration was reduced as much as possible while maintaining sedation with an OAA/S score of 3 or below. The core temperature, forearm temperature, and fingertip temperature were recorded before spinal anesthesia, and just before (baseline) and 15, 30, 45, and 60 minutes after the start of propofol administration. The core temperature, reduction in core temperature from baseline (delta CT), and forearm-fingertip temperature gradient were compared between the two groups. In the P group, the core temperature linearly decreased over time. The core temperature at 30, 45, and 60 minutes was significantly higher in the KP group than in the P group (36.3 +/- 0.2 and 35.9 +/- 0.3, at 60 minutes, mean +/- SD, p < 0.05). The delta CT at 15, 30, 45, and 60 minutes was significantly smaller in the KP group than in the P group. There were no significant differences in the forearm-fingertip temperature gradient between the two groups over the study period. In conclusion, low-dose ketamine administration may confer thermoprotection during spinal anesthesia sedated by propofol.

Adult↗

PubMed2004

[Time course of thoracic epidural pressure and saphenous venous pressure changes with oxytocics after fetus delivery in parturients undergoing cesarean section].

BACKGROUND: We examined the effects of oxytotics administered after fetus delivery on epidural and venous pressures in 40 parturients undergoing cesarean section under spinal anesthesia. METHODS: The subjects received 0.5% isobaric bupivacaine for spinal anesthesia. An epidural catheter placed at T11-12 and a venous catheter placed at left saphenous vein, were connected to pressure transducers to monitor each pressure. The subjects received intravenous methylergometrine 0.2 mg (methylergometrine group: n=20) or oxytocin 10 IU (oxytocin group: n=20) immediately after fetus delivery. Intramyometrial PGF2alpha was additionally administered from 5 minutes after fetus delivery in case of low uterine tone. Statistic analysis was performed with ANOVA. RESULTS: Epidural pressure in the methylergometrine group increased at placental delivery and the increase continued until 15 minutes after delivery (P<0.05). Epidural pressure in the oxytocin group increased at placental delivery and began to decrease at 5 minutes after delivery (P<0.05). Saphenous venous pressure began to increase at 10 minutes after delivery in the methylergometrine group (P<0.05). CONCLUSIONS: The increase in epidural pressure within 5 minutes after fetus delivery would be caused by uterine contraction in both groups. The vasoconstrictive effect in the methylergometrine group is likely to cause the epidural pressure increase after delivery.

Adult↗

PubMed2003

Multicentric osteosarcoma with long-term survival.

We present a 14-year-old girl with multicentric osteosarcoma who has survived for over 9 years to date. The patient first noticed right knee pain in 1992. Radiographs showed a destructive and sclerotic lesion of the right distal femur. Similar small sclerotic lesions were seen in the proximal metaphysis of the right femur, proximal site of the right humerus, and mid-posterior of the left humerus. A diagnosis of multicentric osteosarcoma was made on a biopsy of the right distal femur. The sclerotic lesions of the bilateral humeri disappeared after systemic chemotherapy (T-20), and thus wide excisions of the right distal femur and proximal femur were performed in 1993. New lesions appeared in the left iliac bone and the first lumbar vertebra on bone scintigraphy 24 months after the first surgery. Chemotherapy and wide excisions of the left iliac bone and the first lumbar vertebra were performed. The patient was well at the latest follow-up in April 2003, with no evidence of local recurrence or distant metastasis, but recently renal dysfunction appeared.

Adolescent↗

PubMed2003

Osteoporotic vertebral fracture adjacent to a nonsegmented hemivertebra.

A combination of osteoporotic vertebral fractures and congenital spinal deformity is theoretically possible, but there have been no reports on this combination in the literature. We describe a rare case of an osteoporotic vertebral fracture adjacent to the nonsegmented hemivertebra. A 60-year-old postmenopausal woman who did not recall any specific trauma presented with severe back pain. She had markedly decreased bone mineral density and significant lumbar kyphoscoliosis with a nonsegmented hemivertebra between L1 and L2 on radiographs of the lumbar spine. Magnetic resonance imaging (MRI) revealed a vertebral fracture adjacent to the nonsegmented hemivertebra. Laboratory studies showed increased serum bone-specific alkaline phosphatase (BAP) and urinary type I collagen crosslinked N-telopeptide (NTx). A thoracolumbar brace was applied for 3 months. Daily administration of alendronate normalized her serum BAP and urinary NTx levels. MRI scans of the lumbar spine after 6 months also confirmed normalized signal intensities of the fractured vertebra adjacent to the nonsegmented hemivertebra. The vertebral fracture seemed to be induced by spinal malalignment, increased stress on the adjacent level of the fused segment, and its fragility due to osteoporosis.

Bone Malalignment↗

PubMed2003

Magnetic resonance imaging of spinal involvement by hematopoietic malignancies requiring surgical decompression.

To elucidate magnetic resonance imaging (MRI) findings of the spine with hematopoietic malignancies that require surgery, we retrospectively reviewed the MRI scans in these patients who underwent decompression surgery of the spinal cord or cauda equina. Preoperative MRI scans were obtained from nine patients with spinal involvement by a hematopoietic malignancy who underwent surgery: four with malignant lymphoma and five with multiple myeloma. The marrow involvement pattern, location of signal change of the vertebra, cortical destruction, vertebral fracture, epidural mass formation, paraspinal mass formation, and the wrap-around sign (spread to the extraosseous soft tissues without alteration in the shape of the affected vertebra) were determined by MRI scans. Diffuse marrow involvement (89%), anterior and posterior signal changes of the vertebra (100%), cortical destruction (100%), vertebral fracture (78%), epidural mass formation (78%), and paraspinal mass formation (100%) were commonly observed. The wrap-around sign was seen in only one patient (11%); it was due to vertebral destruction and deformity. Based on these results, we concluded that MRI findings of the spine with a hematopoietic malignancy requiring decompression surgery showed a characteristic diffuse marrow pattern; they also exhibited more expansive and destructive features than previously reported for hematopoietic malignancies without surgery.

Aged↗

PubMed2003

Combined fractures of the odontoid process and upper thoracic spine: two case reports.

We describe two cases of combined fractures of the odontoid process and upper thoracic spine that have not been previously reported. The first patient, a 21-year-old man, sustained an odontoid process fracture with posterior displacement and a fracture-dislocation injury at T4/5 in a motorcycle accident. The second patient, a 66-year-old woman, fell from a cliff and sustained an odontoid process fracture with posterior displacement and a bursting fracture at T3 and T4 with rotation. The first patient exhibited complete paraplegia below the T5 level of the spinal cord. The second patient escaped neurological deficit. Both underwent anterior screw fixation of the odontoid process and posterior fusion of the upper thoracic spine. In both cases the cervical spine seemed to be in hyperextension, and the upper thoracic spine experienced sudden flexion and rotation forces.

Adult↗

PubMed2003

Effects of methylergometrine and oxytocin on thoracic epidural pressure during cesarean section.

AIM: The effects of oxytocics on thoracic epidural pressure during cesarean section were studied in 60 parturients, (American Society of Anesthesiologist physical status, class I or II) after obtaining informed consent. METHODS: The subjects were randomized to either a ergometrine (n = 30) or oxytocin treatment group (n = 30). The subjects were anesthetized with 11-12 mg of intrathecal isobaric bupivacaine (0.5%), and an epidural catheter was placed at Th 11/12, and was connected to a pressure transducer to continuously monitor thoracic epidural pressure. We analyzed epidural pressure, blood pressure, and heart rate 5 min after administering intrathecal bupivacaine (SAB5m), immediately before skin incision (pre-incision), immediately after delivery of the placenta (placenta-del), and 5 min after delivery of the fetus (CS5m). RESULTS: In both groups, epidural pressures were found to be elevated after delivery compared with their levels before the skin incisions were made, (P < 0.0001). Epidural pressures at placenta-del (P = 0.0055) and CS5m (P < 0.0001) were higher than at SAB5m in the ergometrine group. Epidural pressures at placenta-del were also higher than at SAB5m in the oxytocin group (P < 0.0001). Epidural pressures at placenta-del were lower in the ergometrine group compared with the oxytocin group (P = 0.0122), but epidural pressures at CS5m were higher in the ergometrine group compared with the oxytocin group (P < 0.0001). CONCLUSIONS: We conclude that there is an increase in thoracic epidural pressure after fetal delivery, which appears to be associated with uterine contraction.

Blood Pressure↗

PubMed2003

Pregnancy-related increases in sensory perception thresholds are not correlated with serum progesterone levels.

BACKGROUND: Why pregnant women require smaller doses of anesthetic agents still remains speculative. One hypothesis proposes that pregnancy raises sensory perception thresholds, perhaps through a progesterone-mediated effect. This study was undertaken in order to quantify any changes in sensory perception thresholds after parturition and to correlate these changes with the expected decrease in postpartum serum progesterone levels. METHODS: Nineteen gravid women scheduled to undergo an elective Cesarean section consented to participate. Sensory current perception threshold (CPT) testing was performed before and 7 days after an elective Cesarean section. CPT was defined as the minimum amount of constant current stimulation that can be reproducibly detected at a particular frequency. CPT values were determined on the distal phalanx of the nondominant index finger at 2000 Hz, 250 Hz, and 5 Hz monofrequency stimulation. Seven women permitted serum progesterone level determinations at the prepartum and the postpartum CPT testing sessions. RESULTS: Parturition resulted in a statistically significant decrease in the sensory CPT at all 3 frequencies tested, (p < 0.05). However, there was no significant correlation between the postpartum reduction in serum progesterone levels and the observed postpartum decrease in CPT for any frequency, (r < 0.5). CONCLUSIONS: CPTs are significantly reduced after parturition. However, this reduction does not appear to be significantly correlated with the reduction in serum progesterone levels.

Journal Article↗

PubMed2003

Effects of intravenous infusion rate of oxytocin on thoracic epidural pressure in parturients undregoing elective cesarean section.

The effects of intravenous oxytocin on thoracic epidural pressure during cesarean section were studied in 90 parturients (American Society of Anesthesiologists physical atatus class I or II) after obtaining informed consent. The subjects were randomized to either a control (control group; n=30), bolus (bolus group; n=30) or drip treatment group (drip group; n=30). The subjects were anesthetized with 11 approximately 12 mg of intrathecal isobaric bupivacaine (0.5%). An epidural catheter placed at Th 11/12 was connected to a pressure transducer to continuously monitor thoracic epidural pressure. Ten units of oxytocin were administered over 30 seconds in the bolus group and over 5 minutes in the drip group after fetus delivery. We analyzed epidural pressure, mean blood pressure, and heart rate, until 5 minutes after fetus delivery. Epidural pressures in both bolus and drip groups increased after fetus delivery compared with control group (P<0.0001). Epidural pressure immediately after placental delivery in the bolus group was higher than in the control group (p<0.0001) and epidural pressure at 5 minutes after fetus delivery in the drip group was higher than in the control group (p=0.0452). There were no significant differences in changes in blood pressure and heart rate among the three groups. We concluded that the increase in epidural pressure with intravenous administration of oxytocin 10 units over 5 minutes was lower than with intravenous administration of oxytocin 10 units over 30 seconds after fetus delivery.

Adult↗

PubMed2003

A computer simulation of human walking in persons with joint contractures.

Joint contractures decrease the patient's ability to walk, but usually other parts of the body compensate the affected joint contractures. When we restore the gait performance in paraplegic patients by means of functional electrical stimulation, however, we cannot expect complications of compensation. A computer simulation was done to clarify how the contractures affect the gait pattern when no complications of compensation were expected. A seven-segment link mechanical model was used for simulation of human walking in the sagittal plane. In turn, using a personal computer stance and swing-leg joint contractures of the ankle, knee, and/or hip were simulated. When stance-leg contracture was simulated, step length became short with increasing hip flexion contracture. The trunk was tilted backward during knee flexion or ankle plantarflexion contracture simulation. When the swing-leg contracture was simulated, step length became short with increasing knee flexion contracture. We found that hip or knee flexion contracture of < or = 15 degrees, or ankle plantarflexion contracture of < 0 degrees was required to maintain positive step length and forward movement of the center of gravity. These findings suggest that 15 degrees of hip and knee flexion contracture, and 0 degrees of ankle plantarflexion contracture are critical when gait restoration is performed by functional electrical stimulation.

Ankle↗

PubMed2003

Grasping power by means of functional electrical stimulation in a case of C6 complete tetraplegia.

Grasping power (GP) by means of functional electrical stimulation (FES) was measured in a case of C6 complete tetraplegia. This was compared with GP by means of the dynamic tenodesis effect, the flexor hinge splint and the GP of normal female. Palmar grasp strength by means of FES was approximately 16% of the control group and 2.4 times greater than the flexor hinge splint. Lateral grasp strength by FES was approximately 13% of the control group. Our results suggest that FES is more effective than the flexor hinge splint in increasing the GP of tetraplegic patients, and that a stronger and stable GP, which is not affected by wrist position, makes FES practical for improving activities of daily living (ADL).

Adult↗

PubMed2003

Factors related to long-term outcome after decompressive surgery for ossification of the ligamentum flavum of the thoracic spine.

OBJECT: Factors related to long-term surgical outcome of thoracic myelopathy caused by ossification of the ligamentum flavum (OLF) have not been fully investigated. To evaluate these factors, the authors reviewed medical records obtained in patients who had undergone decompressive surgery for thoracic OLF. METHODS: Thirty-four patients in whom decompressive surgery was performed for thoracic OLF (mean follow-up period 8 years) were recruited. Fourteen patients underwent simultaneous decompressive surgery for cervical or lumbar lesions. Patient age, duration of symptoms, OLF type, dural adhesion, neurological status classified by the Japanese Orthopaedic Association (JOA) scale before and after surgery (1 month postoperatively and at final follow up), and recovery rate were reviewed. The ossified ligamentum flavum was classified into five types according to Sato's classification by assessing preoperative computerized tomography scans. The mean preoperative JOA score (5) was significantly improved at 1 month after surgery (7.1) and at final follow up (7.9) (p < 0.05). Recovery rates at 1 month and at final follow up were 34.6 and 44.2%, respectively. No significant correlations were found between age, OLF type, and neurological status before and after surgery. In patients with dural adhesion, which was observed in cases of larger-type OLF (p < 0.02), lower JOA scores were observed compared with those in patients without dural adhesion both preoperatively and at 1 month after surgery (p < 0.05) but not at the final follow-up examination. Higher JOA scores and recovery rates were demonstrated in patients who had undergone simultaneous surgery than in those who had not undergone simultaneous surgery at 1 month (p < 0.05) but not at the final follow up. Using multiple regression analysis, the authors identified the duration of preoperative symptoms as the most important predictor of a high JOA score and recovery rate at the final follow up. CONCLUSIONS: Duration of preoperative symptoms represents the most important predictor of long-term surgery-related outcome in patients treated for thoracic OLF. The type of ossified ligamentum flavum, dural adhesion, and simultaneous surgery for coexistent cervical or lumbar lesions do not appear to influence the long-term postoperative prognosis.

Adult↗

PubMed2003

[Thoracic epidural pressure and peripheral venous pressure in the lower extremity during supine hypotensive syndrome].

BACKGROUND: After induction of spinal anesthesia, thoracic epidural pressure and left saphenous venous pressure were monitored and recorded during supine hypotensive syndrome in 8 pregnant patients who underwent elective cesarean section. METHODS: A 22 G venous catheter was inserted into the left saphena, and an epidural catheter for 18 G needles was positioned 5 cm cephalad in the epidural space through a Tuohy needle at the T 11-12 intervertebral space. Each catheter was connected to a pressure transducer, and recording was started in a supine position immediately after induction of spinal anesthesia with 0.5% isobaric bupivacaine at the L 3-4 intervertebral space. RESULTS: In all patients, epidural pressure and peripheral venous pressure synchronously increased as soon as they began to recover from hypotension and tachycardia regardless of uterine displacement to the left. CONCLUSIONS: The synchronous increase in both pressures was late after the hypotension probably because sympathetic block with spinal anesthesia inhibited vasoconstriction of the lower extremity, a factor to compensate for supine hypotensive syndrome. Only collateral flow via epidural venous plexus emptying into azygos system could not compensate for decreased venous return to the right atrium from obstructed inferior vena cava, and differences in the degree of compression of the inferior vena cava by gravid uterus would affect the recovery from supine hypotension.

Adult↗

PubMed2002

Prevalence of dementia and dementing diseases in Japan: the Tajiri project.

BACKGROUND: Vascular dementia (VaD) has been considered to be more prevalent than Alzheimer disease in Japan. However, this might be the result of overdiagnosis stemming from some problematic diagnosis of VaD or of the frequent use of magnetic resonance imaging to detect cerebrovascular disease in older adults. OBJECTIVES: We investigated the prevalence of dementia and the ratios of dementing diseases. The effects of different criteria for VaD (DSM-IV, Alzheimer's Disease Diagnostic and Treatment Centers [ADDTC], and National Institute of Neurological Disorders and Stroke and the Association Internationale pour la Recherche et l'Enseignement en Neurosciences [NINDS-AIREN]) were considered. Hippocampal atrophy and vascular contribution to dementia were evaluated using magnetic resonance imaging findings. METHODS: We targeted all residents 65 years and older (n = 3207) in Tajiri, Japan, and examined 1654 (participant group 1). Of these, 564 (participant group 2) were randomly selected, and 497 underwent magnetic resonance imaging and diagnosis of dementing diseases. RESULTS: We found the overall prevalence of dementia to be 8.5% (141/1654) in participant group 1. Of these, 21 (14.9%) had a history of stroke. Of the 113 participants who had a history of stroke independent of dementia, 18.6% (21/113) were demented. For participant group 2 (n = 497), 32 were demented. The ratio among the dementia for probable VaD based on the NINDS-AIREN criteria was 18.8% (6/32), whereas that for ischemic vascular dementia was 31.3% (10/32) according to the ADDTC criteria. CONCLUSION: We confirmed the overall prevalence of dementia in adults 65 years and older to be 8.5%. We found that VaD was not a common disorder according to the NINDS-AIREN criteria. Rather, the condition of possible Alzheimer disease with cerebrovascular disease was more common.

Aged↗