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Biomedical subjects

Y Toyama

Publications and source records attributed to Y Toyama.

At least 55 records · Page 3Linked to original sources
PubMed2001

Crystal structures of cyclomaltohexaose (alpha-cyclodextrin) complexes with p-bromophenol and m-bromophenol.

Crystal structures of cyclomaltohexose (alpha-cyclodextrin) complexes with p-bromophenol and m-bromophenol have been determined by single-crystal X-ray diffraction. The space group of the alpha-cyclodextrin-p-bromophenol complex is P2(1)2(1)2(1) with unit cell dimensions of a = 15.318(3), b = 24.733(3), c = 13.457(2) A, and that of the alpha-cyclodextrin-m-bromophenol complex is P2(1)2(1)2 with unit cell dimensions of a = 25.858(7), b = 27.263(8), c = 8.145(3) A. In crystals, the alpha-cyclodextrin-p-bromophenol complex and the alpha-cyclodextrin-m-bromophenol complex form a layer-type and a channel-type molecular packing structure, respectively. The intermolecular hydrogen-bond interactions of the hydroxyl groups of bromophenols are closely related to the molecular packing structure.

Carbohydrate Conformation↗
PubMed2001

Long-term outcomes of standard discectomy for lumbar disc herniation: a follow-up study of more than 10 years.

STUDY DESIGN: A retrospective analysis of the long-term outcomes of standard discectomy for lumbar disc herniation. OBJECTIVES: To investigate the long-term outcomes of standard discectomy to address postoperative problems, including residual low back pain and recurrent herniation. SUMMARY OF BACKGROUND DATA: Most previous investigators found that favorable outcomes of standard discectomy were maintained for the long-term postoperative period. Although they observed postoperative complications such as residual low back pain and recurrent herniation, detailed analyses of these results have not been conducted. METHODS: The long-term follow-up results in patients who were observed for a minimum of 10 years after standard discectomy were evaluated by using the Japanese Orthopedic Association scoring system through direct examinations and questionnaires. Radiography also was used in patients who agreed to visit the hospital, and findings were compared with those on preoperative radiographs. RESULTS: The average recovery rate calculated by using Japanese Orthopedic Association scores was 73.5 +/- 21.7%. Even though residual low back pain was found in 74.6% of the patients, only 12.7% had severe low back pain. The majority of the patients with severe low back pain were under 35 years of age at the time of operation, with preoperative advanced disc degeneration. The final Japanese Orthopedic Association scores in the patients with decreased disc height were significantly lower than those in patients with no decrease. However, the disc height of patients with a recurrent herniation was preserved. CONCLUSION: The long-term outcome of standard discectomy in this series was favorable. Although patients with preserved disc height generally had favorable results, the risk of recurrent disc herniation was high in this population.

Activities of Daily Living↗
PubMed2001

Fluoride concentrations at and near the neonatal line in human deciduous tooth enamel obtained from a naturally fluoridated and a non-fluoridated area.

This study sought to obtain a precise profile of fluoride concentrations at and near the neonatal line in deciduous incisors and canines from the naturally fluoridated area (1.0--1.3 parts/10(6) F in drinking water) of West Hartlepool and the non-fluoridated area (less than 0.1 parts/10(6) F in drinking water) of Leeds in England. An abrasive microsampling method was used to determine the distribution of fluoride and phosphorus concentrations. The profile of fluoride concentrations in 100-microm layers before and after the neonatal line, that is, in the prenatal and postnatal enamel, were significantly higher in teeth from the fluoridated than non-fluoridated areas. It was concluded that the fact that the fluoride concentrations were about the same prenatally and postnatally in deciduous enamel obtained from the fluoridated and non-fluoridated areas indicates that fluoride enters the prenatal deciduous enamel and that it is transferred through the placenta.

Calcium↗
PubMed2001

Repeated thermal therapy improves impaired vascular endothelial function in patients with coronary risk factors.

OBJECTIVES: We sought to determine whether sauna therapy, a thermal vasodilation therapy, improves endothelial function in patients with coronary risk factors such as hypercholesterolemia, hypertension, diabetes mellitus and smoking. BACKGROUND: Exposure to heat is widely used as a traditional therapy in many different cultures. We have recently found that repeated sauna therapy improves endothelial and cardiac function in patients with chronic heart failure. METHODS: Twenty-five men with at least one coronary risk factor (risk group: 38 +/- 7 years) and 10 healthy men without coronary risk factors (control group: 35 +/- 8 years) were enrolled. Patients in the risk group were treated with a 60 degrees C far infrared-ray dry sauna bath for 15 min and then kept in a bed covered with blankets for 30 min once a day for two weeks. To assess endothelial function, brachial artery diameter was measured at rest, during reactive hyperemia (flow-mediated endothelium-dependent dilation [%FMD]), again at rest and after sublingual nitroglycerin administration (endothelium-independent vasodilation [%NTG]) using high-resolution ultrasound. RESULTS: The %FMD was significantly impaired in the risk group compared with the control group (4.0 +/- 1.7% vs. 8.2 +/- 2.7%, p < 0.0001), while %NTG was similar (18.7 +/- 4.2% vs. 20.4 +/- 5.1%). Two weeks of sauna therapy significantly improved %FMD in the risk group (4.0 +/- 1.7% to 5.8 +/- 1.3%, p < 0.001). In contrast, %NTG did not change after two weeks of sauna therapy (18.7 +/- 4.2% to 18.1 +/- 4.1%). CONCLUSIONS: Repeated sauna treatment improves impaired vascular endothelial function in the setting of coronary risk factors, suggesting a therapeutic role for sauna treatment in patients with risk factors for atherosclerosis.

Adult↗
PubMed2001

Specific localization of the basigin protein in human testes from normal adults, normal juveniles, and patients with azoospermia.

Basigin is a transmembrane protein belonging to the immunoglobulin superfamily. Specific localization of the protein in normal human testes, from those of a 2-year-old boy to those of a 50-year-old man, and in testes with Sertoli cell only syndrome and germ cell arrest, is reported. Basigin localization was determined using an immunohistochemical technique with an antibody against human basigin. In the normal adult testes, basigin was detected at the periphery of both spermatocytes older than zygotene and round spermatids. In the juvenile testes, it was expressed in accordance with the appearance of pachytene spermatocytes. In this study, pachytene spermatocytes were detected in an 11-year-old boy. Basigin was not expressed in immature testes with germ cells younger than pachytene spermatocytes, namely in testes from boys aged 2-9 years. In testes from adult patients with Sertoli cell only syndrome, basigin was expressed at the periphery of Sertoli cells, but localization was confined to the adluminal compartment of the seminiferous tubule. In testes with germ cell arrest, the protein was expressed on germ cells from pachytene spermatocytes to step 2 spermatids, where present. The results show that in the normal human testes basigin is expressed with the onset of spermatocyte differentiation. Because human basigin is expressed in adult testes with Sertoli cell only syndrome, the protein seems to be synthesized in Sertoli cells and expression continues after these cells dedifferentiate in the seminiferous epithelium.

Adolescent↗
PubMed2001

Intramuscular spindle cell lipoma: Case report and review of the literature.

Spindle cell lipoma (SCL) is a relatively rare adipocytic neoplasm and is histologically characterized by a mixture of uniform spindle cells and mature fat cells. It occurs predominantly in male patients aged 45-65 years, and in most cases it arises in the subcutaneous tissue of the neck or shoulder. Although the neoplasm sometimes affects unusual sites, only three cases have been reported in which the lesion was intramuscular. Here we present a case of SCL arising in skeletal muscle; to our knowledge, the first report in 10 years. The tumor occurred in the neck of a 50-year-old male patient. Magnetic resonance imaging (MRI) revealed a lipomatous tumor within the right trapezius muscle. The tumor was localized beneath the fascia and was excised completely at surgery. Histologically, the tumor was typical of a spindle cell lipoma with no evidence of malignancy. An immunohistochemical study revealed all spindle cells were strongly positive for CD34. Differential diagnosis is discussed with a review of the literature.

Antigens, CD34↗
PubMed2001

Postnatal development of the testis in Japanese children based on observations of undescended testes.

BACKGROUND: Little is known about the morphological aspects of the postnatal development of the testis in Japanese children. By investigating the normal development of the testis, clinicians in urology can give better strategies to their patients. In addition, the pattern of development will improve the understanding of the effect of xenoestrogens. METHODS: Biopsied testis samples of 68 patients with undescended testes aged between 2 and 21 years were examined by light microscopy. Nineteen patients with normal histology of the bilateral testes were selected for this study. For light microscopy, paraffin sections were stained with hematoxylin and eosin. In addition, using electron microscope, Epon sections stained with lead citrate and uranyl acetate were observed. Semi-thin sections stained with toluidine blue were also used for light microscopy. RESULTS: Gonocytes were observed in the testis of the 2-year-old boys. Spermatocytes developed by 4 years of age and spermatids developed by 11 years of age. The immature Sertoli-Sertoli ectoplasmic junction was observed as early as 4 years of age, and it was completed by 9 years of age. Mature myoid cells were observed by the age of 13 years. Immature Leydig cells were found at 7 years of age and the cells matured by 13 years of age. CONCLUSION: A pattern of postnatal development of the testis in Japanese children was presented.

Adolescent↗
PubMed2001

Traumatic subluxation of the axis after hyperflexion injury of the cervical spine in children.

Six cases of children (four boys and two girls, mean age 11 years) who had traumatic subluxation of the axis (C2) were reviewed retrospectively. Initial radiographs demonstrated no detectable vertebral fracture in any of the children. However, a slight anterior subluxation of C2 was observed in three of the patients. Radiographs, taken at 1 month after injury in all but one patient, revealed a progression of the subluxation and a local kyphosis in all of the patients. Four of the children were treated conservatively with a cervical brace, and an improvement of both the kyphosis and the anterior slippage of C2 was obtained accompanied by an anteroposterior growth of the C3 vertebral body. The kyphosis of two of the patients became severe and, ultimately, these patients underwent fusion surgery. At the follow-up, none of the patients presented with any significant symptom. For the correct diagnosis of traumatic subluxation of C2, sequential radiographs to confirm the progression of subluxation and local kyphosis are mandatory. Conservative treatment rather than early surgical treatment may be chosen for this injury, because mild and moderate kyphosis can be corrected spontaneously by remodeling of the cervical spine.

Adolescent↗
PubMed2001

Malignant lymphoma of the central nervous system with delayed increased accumulation on I-123 IMP SPECT.

Ga-67 citrate scintigraphy in the management of malignant lymphomas is well established. It cannot, however, differentiate malignant from benign lesions because this agent also accumulates in benign inflammatory lesions. The authors present a case of increased I-123 IMP uptake on both early and delayed SPECT images in a patient with malignant lymphoma of the central nervous system. Results show that I-123 IMP SPECT can help differentiate malignant lymphoma from benign lesions and other malignant brain tumors.

Aged↗
PubMed2001

Cubital tunnel release with lift-type endoscopic surgery.

A new technique of endoscopic release of the ulnar nerve at the elbow was designed for cubital tunnel syndrome. After three 5 mm incisions were made along the line of the ulnar nerve, the skin and subcutaneous tissue were lifted up using a fine tape to produce a provisional space. An endoscope was inserted through the one incision, and the constricting ligaments and fascia were released using a retrograde knife inserted through the other incision under endoscopic vision. Eight patients were treated using this method, and successful results were achieved. No neurovascular complications occurred, and all pre-operative complaints were resolved within three weeks. Our surgical series indicated an earlier return to work and daily activity due to early healing of incisions and minimal post-operative pain.

Adult↗
PubMed2001

Macrophage- and neutrophil-dominant arthritis in human IL-1 alpha transgenic mice.

To study the effects of IL-1 alpha in arthritis, we generated human IL-1 alpha (hIL-1 alpha). Transgenic mice expressed hIL-1 alpha mRNA in various organs, had high serum levels of hIL-1 alpha, and developed a severe polyarthritic phenotype at 4 weeks of age. Not only bone marrow cells but also synoviocytes from knee joints produced biologically active hIL-1 alpha. Synovitis started 2 weeks after birth, and 8-week-old mice showed hyperplasia of the synovial lining layer, the formation of hyperplastic synovium (pannus) and, ultimately, destruction of cartilage. Hyperplasia of the synovial lining was due to the accumulation of macrophage-like cells expressing F4/80 molecules. hIL-1 alpha was widely distributed in macrophage- and fibroblast-like cells of the synovial lining cells, as well as synovial fluid monocytes. T and B cells were rare in the synovial fluid, and analysis of marker expression suggests that synoviocytes were directly histolytic and did not act as antigen-presenting cells. In the joints of these mice, we found elevated levels of cells of the monocyte/macrophage and granulocyte lineages and of polymorphonuclear neutrophils (PMNs), most of which expressed Gr-1, indicating that they were mature, tissue-degrading PMNS: Cultured synoviocytes and PMNs from these animals overexpress GM-CSF, suggesting that the hematopoietic changes induced by IL-1 and the consequent PMN activation and joint destruction are mediated by this cytokine.

Animals↗
PubMed2001

Testicular germ cell apoptosis in Bcl6-deficient mice.

Bcl6 protein has been detected in testicular germ cells, mainly spermatocytes, of normal mice, but its physiological role is largely unknown. The number of spermatozoa in the cauda epididymis of adult Bcl6-deficient (Bcl6-/-) mice is lower than that of Bcl6+/+ mice. We have found numerous apoptotic spermatocytes at the metaphase I stage with induction of Bax protein in adult Bcl6-/- testes. Developmentally, the incidence of germ cell apoptosis of Bcl6-/- mice was similar to that of Bcl6+/+ mice until six weeks of age and increased after eight weeks of age. The incidence of apoptosis in heterozygous Bcl6+/- mice was also higher than that of Bcl6+/+ mice. Since the activated form of p38 MAP kinase was detected in spermatocytes of adult Bcl6-/- mice, the germ cell apoptosis may be induced by stressors. Treatment of testes of adult Bcl6+/+ mice with a mild hyperthermia resulted in germ cell apoptosis predominantly in metaphase I spermatocytes with induction of Bax protein and activation of p38 MAP kinase and this apoptosis mimics that in adult Bcl6-/- mice. Thus, Bcl6 may play a role as a stabilizer in protecting spermatocytes from apoptosis induced by stressors.

Animals↗
PubMed2001

Development of new surgical treatments in spinal surgery: expansive open-door laminoplasty and percutaneous nucleotomy.

The outstanding achievements of two renowned spine surgeons, who are alumni of the Department of Orthopaedic Surgery, Keio University, are described. Anterior decompression followed by fusion and laminectomy had been the standard techniques for cervical myelopathy due to disc herniation, spondylosis and ossification of the posterior longitudinal ligament. However, both techniques were not without certain comorbidities. Dr. Kiyoshi Hirabayashi devised an epoch-making expansive open-door laminoplasty, in which both sufficient posterior decompression and preservation of cervical stability are achieved simultaneously with reduced risk of such complications. Dr. Sadahisa Hijikata is the pioneer of a totally new concept treatment, percutaneous nucleotomy, for lumbar disc herniation, one of the most prevailing diseases that cause low back pain and sciatica. He devised this technique to avoid prolonged conservative treatment with associated suffering of the patients and to minimize the chance of morbidity that is occasionally associated with an open surgery. This technique, together with chemonucleolysis, has led to the establishment of intradical or intermediate treatments which lie between conservative and surgical treatments. Both techniques have not only brought the relief of pain and suffering in numerous patients, but have also opened the door to the development of many new modified procedures and technologies. Most importantly, these two techniques still remain as the most viable choice among various similar modifications. The rationale, indictions, technique as well as the present status and future perspective for these two innovative yet fundamental techniques are introduced and discussed.

Cervical Vertebrae↗
PubMed2001

Surgical management of idiopathic spinal cord herniation: a review of nine cases treated by the enlargement of the dural defect.

OBJECT: Spinal cord herniation is a rare cause of progressive myelopathy and can be corrected surgically. In most previous reports, closure of the dural defect was the recommended procedure. The object of this paper is to describe a new procedure in which spinal cord constriction is released by enlarging the hiatus; additionally the postoperative results will be discussed. METHODS: In nine patients with spinal cord herniation, enlargement of the dural defect was performed. In eight patients, neurological deficits resolved immediately after surgery. In one patient with a severe preoperative neurological deficit whose spinal cord herniated massively, deterioration occurred postoperatively. To date, no recurrence of herniation has been observed. CONCLUSIONS: The goals of surgery are to reduce the herniation, return the spinal cord to the normal position, and prevent the recurrence of herniation. The use of sutures to close the dural defect has been the method of choice to date. The surgical space in front of the spinal cord, however, is insufficient to accommodate this procedure safely. Because symptoms are caused by the constriction of the spinal cord at the hiatus, surgical expansion of the hiatus allows the goals of surgery to be achieved. This procedure, which is technically easier and less invasive with regard to the vulnerable spinal cord than the closure of the dural defect, could be a viable alternative for the treatment of this rare disease.

Adult↗
PubMed2000

Impact of longitudinal distance of the cervical spine on the results of expansive open-door laminoplasty.

STUDY DESIGN: A retrospective study in patients who underwent expansive open-door laminoplasty (ELAP) for cervical myelopathy and in whom the cervical alignment was nonlordotic at the final follow-up to analyze the correlation between the longitudinal distance of the cervical spine and surgical results. OBJECTIVES: To determine the impact of longitudinal distance of the cervical spine on surgical results of ELAP and to propose a new concept, the redundant spinal cord, that may influence patient selection for ELAP. SUMMARY OF BACKGROUND DATA: Results in many studies have demonstrated that postoperative cervical alignment has significant effect on surgical results, and spines that are malaligned are thought to deteriorate. The current surgical data showed that not all patients with postoperative malalignment had poor surgical results. Patients with cervical spondylotic myelopathy (CSM) tended to have better clinical results than those with ossification of the posterior longitudinal ligament (OPLL). METHODS: Results in 70 patients who underwent ELAP for cervical myelopathy with postoperative cervical malalignment were investigated. The longitudinal distance index (LDI) was defined as the length of a vertical line between the posteroinferior edges of C2 and C7 divided by the anteroposterior diameter of C4 and was measured on lateral neutral radiographs at final follow-up. Correlation between LDI and surgical results represented by Japanese Orthopedic Association scores and percentage of recovery were analyzed statistically in each patient. RESULTS: Patients with CSM had smaller LDI and better surgical results than those with OPLL. Weak but significant negative correlation was detected between LDI and percentage of recovery, indicating that longitudinal distance of the cervical spine may have some degree of impact on the surgical results of ELAP. CONCLUSION: A decrease in LDI represents shortening of the cervical spine caused by multiple disc degeneration and may influence surgical results of ELAP by inducing redundancy of the spinal cord in patients with postoperative malalignment.

Cervical Vertebrae↗
PubMed2000

Increased signal intensity of the spinal cord on magnetic resonance images in cervical compressive myelopathy. Does it predict the outcome of conservative treatment?

STUDY DESIGN: Correlation between a lesion of the spinal cord that elicits increased signal intensity (ISI) on magnetic resonance images (MRIs) and the outcome of conservative treatment for cervical compressive myelopathy was retrospectively investigated. OBJECTIVE: To investigate whether ISI could predict the outcome of conservative treatment for cervical compressive myelopathy. SUMMARY OF BACKGROUND DATA: It is unknown whether ISI is related to the outcome of conservative treatment for cervical compressive myelopathy. METHODS: Fifty-two patients with mild cervical myelopathy underwent conservative treatment with a cervical brace. The compressive lesions were spondylosis in 29 patients, disc herniation in 12, and an ossification of the longitudinal ligament in 11. They also underwent MRI (1.5 T), and ISI was evaluated on T2-weighted sagittal and axial images. The ISI areas were classified as focal or multisegmental. Thirty-nine patients underwent follow-up MRI after a mean interval of 2 years, 4 months. The transverse area of the spinal cord was also measured on T2-weighted axial images. The outcome of conservative treatment was assessed using the Japanese Orthopedic Association Score (JOA score). Patients showing either an improvement in the JOA score or with a JOA score of 15 or more were considered to have a satisfactory outcome. RESULTS: The average JOA score was 14.0 +/- 1.4 (range, 10-16) before conservative treatment and 14.4 +/- 1.9 (range, 10-17) at follow-up. The average gain in the JOA score was 0.4 points +/- 1.9 (range, -5 to +6). The outcome was satisfactory in 36 patients (69%). An area of ISI was observed in 34 patients (65%) before treatment (24 focal and 10 multisegmental). A satisfactory outcome was obtained in 78% of the patients without ISI, in 63% of those with focal ISI, and in 70% of those with multisegmental ISI. No statistically significant difference was seen among these three groups in the percentages of patients with satisfactory outcome, JOA scores before and after treatment or transverse spinal cord area. Of the 39 patients who were re-examined by MRI, 28 showed an area of ISI. The ISI regressed in five patients (18%). Satisfactory outcome was obtained in all 5 patients with regression of ISI, in 16 (70%) of the 23 patients without regression of ISI, and in 10 (91%) of the 11 patients without ISI apparent on the the first images (difference, not significant). CONCLUSIONS: Increased signal intensity was not related to a poor outcome of conservative treatment or severity of myelopathy in the patients with mild cervical myelopathy.

Adult↗