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Biomedical subjects

M Kawakami

Publications and source records attributed to M Kawakami.

At least 109 records · Page 6Linked to original sources
PubMed2000

Dental follicle cell-conditioned medium enhances the formation of osteoclast-like multinucleated cells.

An influx of mononuclear cells and the subsequent increase of osteoclasts around tooth germs suggests that the dental follicle (DF) regulates or influences bone resorption required for tooth eruption. In order to study the effects of DF cell products on osteoclast formation during tooth eruption, a conditioned medium (CM) was created in which DF cells were added to mouse bone marrow cultures. Tartrate-resistant acid phosphatase (TRAP)-positive osteoclast-like multinucleated cells were formed in the presence of 10 nM 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. The CM, dose-dependently, stimulated the formation of TRAP-positive cells in the presence of 1,25(OH)2D3 for 14 days culture. The number of these cells decreased due to degradation in the control culture. A semi-solid methylcellulose assay in the presence of CM showed little expression of colony-stimulating activity. These results suggest that the DF cells of a developing tooth produce factor(s) that enhance osteoclast formation and bone resorption necessary for tooth eruption.

Acid Phosphatase↗
PubMed2000

Role of leukocytes in radicular pain secondary to herniated nucleus pulposus.

Some studies have assessed inflammatory cells such as macrophages, lymphocytes, and neutrophils in herniated lumbar disc tissues using histologic analysis. However, there is no consensus regarding the relationships between clinical symptoms, including radicular pain and the presence of inflammatory cells. It has been shown that autologous nucleus pulposus relocated on the lumbar nerve root in rats produces time dependent and reversible mechanical hyperalgesia, which is thought to be a pain related behavior in peripheral neuropathic pain models. The purpose of this study was to determine whether leukocytes play a role in the mechanical hyperalgesia induced by the nucleus pulposus and to characterize the role of leukocytes in radicular pain attributable to lumbar disc herniation. Nitrogen mustard was used to induce and evaluate leukocytopenia in rats. Sensitivity to mechanical noxious stimuli was measured quantitatively, and inflammatory cells in granulation tissue around the nerve root were examined histologically. The nucleus pulposus produced neither mechanical hyperalgesia nor abundant inflammatory cells in rats with nitrogen mustard induced leukocytopenia. Neuropathic pain produced by the nucleus pulposus, when placed on the nerve root, may be related to inflammatory cell infiltration induced by relocation of the nucleus pulposus, rather than the nucleus pulposus itself.

Animals↗
PubMed2000

A comparative study of surgical approaches for cervical compressive myelopathy.

Since 1986, the authors have used anterior decompression and fusion to treat patients with one- or two-level lesions without spinal canal stenosis (Group A) and laminoplasty for patients with more than three-level lesions or spinal canal stenosis (Group P). The aim of this study was to compare surgical outcomes of anterior and posterior approaches for patients with cervical myelopathy because of spondylosis and disc herniation and to determine the cause of poor neurologic recovery after surgery. One hundred thirty-six patients were followed up for an average of 5.6 years. There were no significant differences in gender, preoperative neurologic deficits, axial symptoms, or duration of symptoms before surgery between the two groups. Mean recovery rates for disc herniations were 71.1% and 71.9% in Groups A and P, respectively. For spondylosis, mean recovery rates were 49.0% and 58.6% in Groups A and P, respectively. There were no differences in recovery rate for patients with either spinal disorder between Groups A and P. The neurologic recovery of patients with kyphotic spinal cord was inferior to that of patients with lordotic or straight spinal cord. It is possible that acquisition and maintenance of lordosis result in improvement of clinical outcomes after surgery for patients with myelopathy.

Aged↗
PubMed2000

Urokinase cisternal irrigation therapy for prevention of symptomatic vasospasm after aneurysmal subarachnoid hemorrhage: a study of urokinase concentration and the fibrinolytic system.

BACKGROUND AND PURPOSE: Cisternal irrigation therapy with urokinase (UK) was performed in multiple institutions to prevent symptomatic vasospasm. The efficacy and safety of this therapy were evaluated, and the optimal concentration of UK was estimated. METHODS: This therapy was performed in 28 patients who underwent surgery within 72 hours of the onset of severe subarachnoid hemorrhage (Fisher's group 3, CT number [Hounsfield units] >60). After the aneurysm was clipped, irrigation tubes were placed in the Sylvian fissure (inlet) unilaterally and in the prepontine or chiasmatic cistern (outlet). Lactated Ringer's solution with UK (30, 60, or 120 IU/mL) was infused at a rate of 30 mL/h. The presence of symptomatic vasospasm was evaluated by changes in the clinical symptoms and the presence of a new low-density area on CT scan. Drained irrigation fluid and peripheral blood were examined chronologically to evaluate the fibrinolytic system. RESULTS: Symptomatic vasospasm was observed transiently in 3 cases (10.7%) without any low-density area on CT scan. In the 120-IU/mL group, no symptomatic vasospasm occurred. Analysis of drainage fluid suggested that UK 120 IU/mL is effective. The mean values of total drained blood volume for the respective groups were as follows: 58 mL in 30 IU/mL, 106 mL in 60 IU/mL, and 143 mL in 120 IU/mL. No abnormal changes were observed in the coagulative and fibrinolytic systems after UK irrigation. CONCLUSIONS: These results suggest that cisternal irrigation therapy with UK is safe and effective for the prevention of symptomatic vasospasm after aneurysmal subarachnoid hemorrhage.

Biomarkers↗
PubMed2000

Antiphospholipid syndrome with cortical blindness resulting from infarction around the posterior cerebral artery in an elderly woman.

An 87-year-old woman with antiphospholipid syndrome accompanied by cortical blindness and thalamic syndrome resulting from infarction of the posterior cerebral artery is reported. She was hospitalized because of laceration of the head. Two months later, she complained of loss of visual acuity, sharp pain and numbness involving the left half of the body except her face. New right posterior lobe infarction and the existence of old left infarctions were confirmed by serial CT scans. Helical CT scan revealed embolization of the posterior cerebral artery with atherosclerotic stenosis. Serological examination showed biologically false-positive and positive findings for lupus anticoagulant. She was treated with warfarin potassium and clonazepam.

Aged↗
PubMed2000

Awareness of the harmful effects of smoking and views on smoking cessation intervention among Japanese medical students.

OBJECTIVE: To clarify attitudes toward smoking, and views on smoking intervention among medical students, as well as to teach them the harmful effects of smoking. SUBJECTS AND METHODS: We carried out an anonymous questionnaire among 2nd and 5th year Japanese medical students and 1,137 of them responded. RESULTS: Smoking prevalence was 25.1% in men and 8.8% in women in the 2nd year and 43.1% and 9.3%, respectively, in the 5th year. Most respondents thought smoking is harmful to health, but smokers were more likely to think it is not so harmful. In both groups, 97% of the respondents knew lung cancer was related to smoking. Apart from this, knowledge of smoking-related diseases (pulmonary emphysema, coronary heart disease, peptic ulcer, and neonatal death) increased by the 5th year but the rates of recognition were generally less than 50%. Many of them learned about the deleterious effects mainly at places other than medical class (80.2% in the 2nd, 44.9% in the 5th year). About 90% intended to perform smoking intervention in the future, but only one-third were actively interested. More than 70% of the respondents thought that doctors should carry out smoking cessation advice depending on the disease, while the rate of those who thought so irrespective of the disease did not reach 20%. Smokers thought less actively about smoking intervention than current nonsmokers. CONCLUSION: The awareness of the harmful effects of smoking and intention to perform smoking intervention in the future as doctors seemed unsatisfactory among Japanese medical students.

Adult↗
PubMed2000

Fatal hepatic failure caused by chemotherapy-induced reactivation of hepatitis B virus in a patient with hematologic malignancy.

A patient with hematologic malignancy and hepatitis B virus (HBV) infection received chemotherapy containing a glucocorticoid. The patient developed severe hepatitis after chemotherapy and, despite achieving complete remission of the malignancy, died of hepatic failure. We carried out a retrospective study of changes in the serological markers of HBV in this patient. Both serum hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (HBsAb) were negative on admission. During the course of chemotherapy, HBsAg gradually became positive, but no liver dysfunction was apparent until after completion of the chemotherapy. The patient showed no initial evidence of being a latent HBV carrier. Therefore, we believe that screening for HBsAg is insufficient for detecting latent HBV carriers, and that investigation for hepatitis B core antibody (HBcAb) is essential.

Aged↗
PubMed2000

[Preoperative bronchial arterial infusion of docetaxel for squamous cell carcinoma of the lung--clinical evaluation and correlation between anti-tumor effect and apoptosis].

As an induction therapy for advanced lung cancer, a patient received bronchial arterial infusion of 30 mg/m2 of docetaxel (TXT). Two weeks after infusion, although the tumor size was not reduced, the central necrotic area was significantly increased. There were no adverse effects. Nineteen days after infusion, we performed a right lower lobectomy and lymph nodal dissection. The resected specimen was examined by immunohistochemistry and biochemistry. The anti-tumor effects were evaluated clinically and the correlation between arterial TXT infusion therapy and apoptosis was studied. Hematoxylin and eosin staining demonstrated moderately differentiated squamous cell carcinoma associated with central necrosis, and cells with chromatin condensation scattered in both the necrotic areas and the margin of this area. It is thought that these findings were the result of this therapy, rather than just the self-necrosis seen in an untreated group.

Aged↗
PubMed2000

[Diagnosis of breast cancer extent using dynamic multidetector-row CT: correlation between MPR imaging and pathological cross-sections].

PURPOSE: To evaluate the clinical usefulness of dynamic multidetector-row CT (dynamic MD-CT) for the detection of intraductal extension of breast cancer. MATERIALS AND METHODS: Dynamic MD-CT was performed in 31 patients with breast masses (26 invasive ductal carcinomas, 4 non-invasive ductal carcinomas and one benign lesion). We grouped the cases into four categories according to the degree of intraductal extension of the main tumor: IDS1: intraductal component less than 1 cm, IDS2: intraductal component 1 cm to 2 cm, IDS3: intraductal component 2 cm to 3 cm, IDS4: intraductal component more than 3 cm. To achieve complete CT-pathologic correlation, we retrospectively reconstructed MPR in the same plane as the histological cross-section. RESULTS: Thirty breast carcinomas (100%) showed strong enhancement in both the first and second phases of contrast enhanced dynamic MD-CT. The sensitivity and specificity of dynamic MD-CT for the detection of the intraductal component were 80.0% (12/15) and 100% (15/15). The accuracy of detection for the four tumor categories was 100% (15/15) for IDS1, 25% (1/4) for IDS2, 42.9% (3/7) for IDS3, and 100% (4/4) for IDS4. CONCLUSION: Dynamic MD-CT of the breast was found to be effective for the detection of intraductal extension of breast carcinoma and thought to be useful in the preoperative assessment of indications of breast-conserving surgery.

Adult↗
PubMed2000

[Low body mass index and exercise capacity in patients with chronic obstructive pulmonary disease (COPD)].

This study examined retrospectively the relationships between body weight and exercise capacity in patients with chronic obstructive pulmonary disease (COPD). Seventeen patients with a %FEV1 less than 55% (mean +/- SD 36% +/- 8.8%) and minimum body weights of the body mass index (BMI) less than 20 (17.3 +/- 1.7) performed incremental exercise testing using a treadmill. Seventeen %FEV1-matched control patients with normal body weights were selected. There were no significant differences in the patients' characteristics or their pulmonary function tests (including vital capacity, carbon monoxide diffusing capacity, and arterial blood gases). Low BMI patients Is this the weaning of (67.8 +/- 6.3 years old) were younger than the control patients (73.1 +/- 8.5 years old), but the difference was not statistically significant. The exercise capacities of low BMI patients were significantly superior to those of the control patients (316.5 +/- 171.5 seconds vs 204.1 +/- 116.3 seconds, p = 0.038) and total walking distance without statistical significance (194.9 +/- 117.0 m vs 125.7 +/- 98.0 m, p = 0.071). Also, low BMI patients achieved higher maximal minute ventilation volume during exercise than the controls. The major factor limiting exercise in patients with low BMI was ventilation. Moderately low body weight may not be a risk factor in Japanese COPD patients.

Aged↗
PubMed1999

Experimental spinal fusion using sintered bovine bone coated with type I collagen and recombinant human bone morphogenetic protein-2.

STUDY DESIGN: Posterolateral lumbar transverse process fusion using recombinant human bone morphogenetic protein (rhBMP)-2 carried by sintered bovine bone and Type I collagen complex was compared with fusion achieved using autogeneous bone graft or sintered bovine bone alone. OBJECTIVES: This study examined the efficacy of sintered bovine bone coated with Type I collagen as a carrier of rhBMP-2 for lumbar intertransverse process arthrodesis. SUMMARY OF BACKGROUND DATA: Posterolateral intertransverse process arthrodesis using osteoinductive growth factors is performed experimentally in the lumbar spine. The previous studies revealed the efficacy of osteoinductive factors applied to carriers having no bony structures, such as collagen sheet or polylactic acid polymer, for the spinal fusion. However, in their studies, a large amount of osteoinductive proteins have been applied for the spinal fusion. We used the sintered bovine bone "True Bone Ceramics" (TBC; Koken Co., Tokyo, Japan) coated with type I collagen as the carrier. True Bone Ceramics is the only biomaterial possessing a natural trabecular structure and an organized crystal of bone minerals. METHODS: Twenty-two adult rabbits underwent bilateral lumbar intertransverse process arthrodesis at L4-L5. The animals were divided into four groups and had materials implanted as follows: autologous bone group, grafted autologous corticocancellous bone harvested from the posterior iliac crest; implanted TBC group; TBC collagen group, implanted TBC coated with Type I collagen infiltrating into the porous space; and BMP group, implanted sintered bovine bone coated with Type I collagen infiltrated with 100 micrograms of rhBMP-2. Spinal fusion was evaluated by radiographic analysis, manual palpation, biomechanical testing, and histologic examination 6 weeks after surgery. RESULTS: Two rabbits were killed because of infection and lumbar plexus palsy. Radiographs of the BMP group showed a homogeneous fusion mass at the intertransverse area, and stability was confirmed by dynamic radiographs at 3 and 6 weeks after surgery. In the BMP group, a bony mass in the intertransverse area was more prominent than in the other groups. The BMP group had a higher fusion rate based on manual palpation than the-other groups, and BMP fusions showed significantly higher tensile strength and stiffer fusion. The histologic findings in the BMP group demonstrated membranous bone and endochondral bone formations between the transverse process and the fusion mass. In the other groups, continuous trabecular bone formation was observed in the area surrounding the transverse process, but gaps between grafted fragments and less mature bone formation were present in the intertransverse area. CONCLUSIONS: Sintered bovine bone coated with Type I collagen and rhBMP-2 resulted in a higher fusion rate than the autograft and can be used as a carrier for rhBMP-2 in spinal fusion.

Animals↗
PubMed1999

Effects of basic fibroblast growth factor on spontaneous resorption of herniated intervertebral discs. An experimental study in the rabbit.

STUDY DESIGN: Histologic examination was performed on the autologous intervertebral disc material that was removed from the intervertebral space at L1-L2 and then relocated to the L4 posterior epidural space after the addition of basic fibroblast growth factor (bFGF) in a rabbit. OBJECTIVES: To evaluate whether basic fibroblast growth factor influences the resorption process of the herniated intervertebral disc through the promotion of angiogenesis and chemotaxis. SUMMARY OF BACKGROUND DATA: It has been reported that newly formed vessels, inflammatory cells, and their products may play an important role in the spontaneous resorption process of herniated intervertebral discs. In a rabbit model that mimics the sequestration type of intervertebral disc herniation, it has been reported that the autologous intervertebral disc material that relocated into the epidural space was penetrated by newly formed vessels originating from the epidural fat tissue. Therefore, it is possible that promotion of angiogenesis may influence the resorption of herniated intervertebral discs. Basic fibroblast growth factor is well known as an angiogenesis stimulation factor in vivo. METHODS: Thirty-six adult rabbits were divided into three groups. The L1-L2 intervertebral disc was partially incised through a retroperitoneal approach in each rabbit. The harvested disc material, which contained nucleus pulposus and anulus fibrosus, was immersed in one of three kinds of solution before relocation into the posterior epidural space at L4. In the control group, the harvested intervertebral disc was immersed in physiologic saline for 2 hours before relocation. In the group receiving 5 micrograms bFGF, the disc was immersed in 5 micrograms/mL bFGF for 2 hours before the relocation. In the group receiving 20 micrograms bFGF, the disc was immersed in 20 micrograms/mL bFGF for 2 hours before the relocation. Rabbits of each group were killed for histologic examination 1, 2, 4, and 8 weeks after surgery. RESULTS: In the bFGF-treated groups, newly formed vessels were observed to be in more numerous than those in the control group, 1 and 2 weeks after surgery. The number of inflammatory cells, including macrophages, lymphocytes, and fibroblasts, also increased in the bFGF-treated groups. The period from the surgery to the degradation of the intervertebral disc in the bFGF-treated groups was shorter than that in the control group, although the resorption process of the relocated discs was also observed in the control group. The size of relocated intervertebral discs in the bFGF-treated groups decreased at a higher rate than in the control group as time progressed. The rate of decrease in the size of discs in the group treated with 20 micrograms bFGF was more than that in the group treated with 5 micrograms. CONCLUSIONS: Epidural injection of bFGF facilitated the resorption of the intervertebral disc relocated to the epidural space.

Animals↗
PubMed1999

Cyclic mechanical stretch stress increases the growth rate and collagen synthesis of nucleus pulposus cells in vitro.

STUDY DESIGN: A rabbit model designed to investigate the effects of applied cyclic tensile stress on the cell division rate and the collagen synthesis in the rabbit nucleus pulposus cells in vitro. OBJECTIVE: To evaluate the effects of mechanical stress on nucleus pulposus cells, thus adding to the understanding of the adaptation of the intervertebral disc to mechanical stress. SUMMARY OF BACKGROUND DATA: Intervertebral disc cells in vivo are exposed to a multitude of physical forces during physical motion. Although it is known that in intervertebral disc disease, a common pathway of disc degeneration is mechanical stress on the nucleus pulposus or the anulus fibrosus or both, the underlying mechanism has been less well defined. METHODS: Nucleus pulposus cells were isolated from 4-week-old Japanese white rabbits. These cells were subjected to the mechanical cyclic stretch stress using a computerized, pressure-operated instrument that physically deformed the cells. The DNA synthesis rate, collagen synthesis rate, and cell cycle progression were measured. RESULTS: Cyclic tensile stretch increased the DNA synthesis rate in nucleus pulposus cells and in the population of cells in the S phase of the cell cycle during 1 to 2 days of subjugation to stress. Cyclic tensile stretch also increased collagenous protein synthesis in nucleus pulposus cells during 1 to 4 days of stress. CONCLUSIONS: Mechanical stress on nucleus pulposus cells promotes the proliferation of cells and alters the properties of intervertebral disc cells. This study may reflect the adaptation of the intervertebral disc to increased motion and stress.

Adaptation, Physiological↗
PubMed1999

Forearm heating band used in apheresis therapy that employs a positive-temperature coefficient polymer heater.

For standard apheresis therapy, blood is withdrawn from the ante-cubital vein of one arm and processed blood is returned to a vein of the opposite arm. For low-density lipoprotein apheresis or for the treatment of patients with Guillain-Barré syndrome, a sufficient quantity of blood is readily obtained by this method. In some patients with collagen diseases, however, it may be difficult to secure a reliable vein due to vasospasm or it may not be possible to obtain sufficient blood flow. We constructed a forearm heating band by employing a positive-temperature coefficient heater and evaluated the device to determine whether the application of heat to the forearm is effective in securing a sufficient quantity of blood in those patients with collagen disease (eight with systemic lupus erythematosus and one with multicentric Castleman's disease). Both forearms were heated by using this heating band, in addition to systemic warming with an electric blanket, starting 30 minutes before apheresis. The body surface temperature was sequentially monitored by employing a needle-type thermometer. The surface temperature of the heated area became constant at 37.6+/-0.3 degrees C within approximately 20 minutes (34.7+/-1.3 degrees C at the control site, P<0.001). It was found that this heating band makes it possible to obtain the quantity of blood that is necessary for apheresis and reduce the time required for the treatment. No adverse effects attributable to heating of the forearm were recognized.

Blood Component Removal↗
PubMed1999

Filtration leukocytapheresis therapy in rheumatoid arthritis: a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To determine the efficacy and safety of filtration leukocytapheresis (LCP) for the treatment of rheumatoid arthritis (RA). METHODS: Twenty-five patients with drug-resistant RA were randomly assigned to undergo filtration LCP and 7 to undergo sham apheresis (control group) in a randomized, double-blind, placebo-controlled study. Three apheresis procedures were performed, with 1-week intervals between procedures. The efficacy of filtration LCP was evaluated according to the American College of Rheumatology definition of improvement in RA. Medications for each patient were unchanged for at least 6 months prior to enrollment and throughout the study. RESULTS: Tender joint counts, swollen joint counts, patient assessment of pain and global severity, physician assessment of global severity, and Health Assessment Questionnaire Disability Index were significantly improved in the LCP group compared with the control group (P < 0.05 for patient assessment of pain; P < 0.01 for all others). Seventy-nine percent of the patients in the LCP group exhibited significant overall improvement, while none of the patients in the control group were improved (P < 0.001). CONCLUSION: The results indicate that filtration LCP is an effective and well-tolerated treatment for patients with drug-resistant RA.

Adult↗
PubMed1999

Effects of sintered bovine bone on cell proliferation, collagen synthesis, and osteoblastic expression in MC3T3-E1 osteoblast-like cells.

To determine the function of biomaterials on osteoblasts, we studied the effects of two different biomaterials, sintered bovine bone (true bone ceramic) and hydroxyapatite-related material, on DNA and collagen synthesis and osteoblastic expression in osteoblast-like cells in vitro. Osteoblasts cultured with true bone ceramic exhibited greater increases in DNA and collagenous protein synthesis and alkaline phosphatase activity than those cultured with hydroxyapatite. Furthermore, expression of mRNA for type-I collagen and osteocalcin, as assessed by reverse transcription-polymerase chain reaction, was higher in cultures grown on true bone ceramic or hydroxyapatite than in those grown with glass fragments, and levels of gene expression in true bone ceramic and hydroxyapatite cultures were at almost the same level. These findings indicate that osteoblasts cultured with true bone ceramic increase their activity, suggesting that true bone ceramic may be a more favorable substrate than hydroxyapatite for growth and differentiation of osteoblast-like cells.

Alkaline Phosphatase↗
PubMed1999

mRNA expression of interleukins, phospholipase A2, and nitric oxide synthase in the nerve root and dorsal root ganglion induced by autologous nucleus pulposus in the rat.

The purpose of this study was to examine whether mRNA of interleukin-A2, interleukin-6, phospholipase A2, and nitric oxide synthase was expressed in the nerve root and dorsal root ganglion of an animal model in which exposure to the nucleus pulposus induced mechanical hyperalgesia, a pain-related behavior. Autologous nucleus pulposus obtained from coccygeal discs was relocated on the L4 and L5 lumbar nerve roots after partial laminectomy. The reflex response to noxious mechanical stimuli to the hindpaw was measured preoperatively and to 4 weeks postoperatively. With a reverse transcription-polymerase chain reaction technique, expression of interleukin-1beta, interleukin-6, phospholipase A2, and inducible nitric oxide synthase genes in the nerve root and dorsal root ganglion was observed at 1, 2, and 4 weeks postoperatively. Mechanical hyperalgesia was observed from 3 days to 2 weeks postoperatively. The expression of interleukin-1beta, phospholipase A2, and inducible nitric oxide synthase mRNAs increased after only 1 week. This increase was related to mechanical hyperalgesia. Expression of interleukin-6 was detected in the neural tissue over time. It is possible that interleukin-1beta, phospholipase A2, and inducible nitric oxide in the nerve root or dorsal root ganglion, or in both, produce sciatic pain in the early stage of herniation of the lumbar disc.

Animals↗