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Biomedical subjects

N Shirasaki

Publications and source records attributed to N Shirasaki.

At least 19 recordsLinked to original sources
PubMed2006

Analysing mass balance of viruses in a coagulation-ceramic microfiltration hybrid system by a combination of the polymerase chain reaction (PCR) method and the plaque forming units (PFU) method.

Virus removal experiments using river water spiked with bacteriophages were conducted by an in-line coagulation-ceramic microfiltration hybrid system to investigate the effects of filtration flux (62.5 and 125 L/(m2 x h)) and type of virus (Qbeta and MS2) on virus removal. In addition, the mass balance of viruses through the hybrid system was analysed by quantifying the infectious and inactive viruses by a combination of the polymerase chain reaction (PCR) method and the plaque forming units (PFU) method. Even when the system was operated at high filtration flux (125 L/(m2 x h)), high virus removal (> 6 log) with short coagulation time (2.4 s) was successfully achieved by dosing polyaluminium chloride (PACI) at more than 1.08 mg-Al/L. Removal performances were different between Qbeta and MS2, although their diameters are almost the same: greater virus removal was achieved for MS2 at PACI dosing of 0.54 mg-Al/L, and for Qbeta at PACI dosing of more than 1.08 mg-Al/L. The combination of the PCR and PFU methods revealed that two phenomena, adsorption to/entrapment in aluminium floc and virucidal activity of PACI, partially account for the high virus removal in the coagulation-MF hybrid system.

Bacteriophages↗
PubMed1998

Binding characteristics of bovine lactoferrin to the cell surface of Clostridium species and identification of the lactoferrin-binding protein.

The binding characteristics of bovine lactoferrin (bLf) to cells of the Clostridium species were observed by using a horseradish peroxidase-bLf conjugate. A bLf-binding protein (BP) having a relative molecular mass of about 33 kDa was confirmed in the surface layer components from 7 strains of the Clostridium species. The binding of the conjugate to bLf-BP or C. perfringens was strongly blocked by intact Lfs, lysine or arginine residues modified bLf, and deglycosylated bLf, but was not by other milk proteins or by the constituent sugars of glycan. Bacterial growth was inhibited by bLf, but was slightly inhibited by lysine residues modified bLf or deglycosylated bLf. Lactoferricin B did not block the binding of the conjugate, but strongly inhibited the bacterial growth. This suggests that the lysine or arginine residues and glycan of bLf hardly participated in binding bLf to the bacterial cells, but that the amino acid residues and glycan played an important role in inhibiting the growth of bacteria.

Amino Acids↗
PubMed1996

Cervical spondylotic radiculopathy involving two adjacent nerve roots. Anterior decompression through a single level intervertebral approach.

We describe a single level intervertebral approach to decompress two adjacent involved nerve roots in cases of cervical spondylosis. The operation was undertaken in 4 patients. We carried out discectomy, partial excision of the vertebral body with removal of the anteromedial part of the pedicles, removal of osteophytes and excision of the posterior longitudinal ligament, followed by an anterior interbody fusion. Fusion was achieved with the spine in normal lordosis and without complications. Pain and motor weakness was relieved in every case. This procedure can maintain movement at one additional disc level and has a better fusion rate than multilevel inter-body fusion.

Adult↗
PubMed1992

Corticotroph cell hyperplasia in a patient with Addison disease: case report.

A woman with Addison disease developed hyperpigmentation, headache, and nausea despite conventional replacement therapy with cortisone. Excessively elevated plasma adrenocorticotropic hormone (ACTH) with absence of response to administration of corticotropin-releasing factor (CRF), and roentgenological evidence of enlargement of the sella turcica, as well as detection of enlarged pituitary gland on magnetic resonance images, led to a diagnosis of ACTH-producing microadenoma, which was removed by transsphenoidal microsurgery. The specimen obtained at surgery evidenced corticotroph hyperplasia, as demonstrated by immunohistochemical staining for ACTH. Fine structure exhibited densely granulated cells with a few bundles of microfilaments and an abundance of large lysosomal bodies. Surgical removal of the hyperplasia alleviated the patient's symptoms, and hyperpigmentation faded remarkably. Her plasma ACTH level returned to normal, has remained normal for more than 3 years, and responds adequately to CRF administration.

Addison Disease↗
PubMed1991

Structural abnormalities in freeze-fractured sciatic nerve fibres of diabetic mice.

Nodal and paranodal regions of myelinated sciatic nerve fibres from diabetic (db/db) mice were examined in freeze fracture replicas. In some fibres, the axolemma was found to display abnormalities in the paranodal region. These include shallow, undifferentiated junctional indentations, thinning of the indentations with widening of the non-junctional grooves between them, particle clusters within the non-junctional grooves, and patches in which axolemmal E-face particles are distributed randomly rather than in the form of linear strings within grooves. Nodal structure, in contrast, is hardly affected. Nodal E-face and P-face particle densities in db/db axons are not significantly different from those in age-matched controls, although we found a few examples in which the E-face density fell slightly below the normal range. Occasional fibres showing evidence of paranodal or segmental demyelination were also seen. The results support paranodal pathology as a potential basis for reduced nerve conduction velocity in diabetic nerves but provide no evidence for significant changes in nodal structure or in nodal Na channel density in sciatic nerve fibres of the db/db mouse.

Animals↗
PubMed1991

Os odontoideum with posterior atlantoaxial instability.

Nine patients who had os odontoideum with posterior atlantoaxial instability are reviewed. Three parameters were measured on the lateral radiographs: the distance from the os odontoideum to the spinous process of the axis in extension (Dext), the distance from the os odontoideum to the posterior arch of the atlas (Datl), and the degree of instability (Inst). Patients were classified into four groups: Group I, local symptoms (N = 3); Group II, transient myelopathy (N = 0); Group III, progressive myelopathy (N = 6); and Group IV, cerebral symptoms (N = 0). The development of cervical myelopathy was not related to degree of instability but to distance from the os to the spinous process of the axis (Dext). Dext was more than 16 mm in Group I and less than or equal to 16 mm in Group III. Five of six patients in Group III underwent myelography. Based on myelographic findings, Group III was further subdivided into two groups, Group IIIA (N = 2) and Group IIIB (N = 3), according to the following characteristics: In Group IIIA, the distance from the os to the posterior arch of the atlas was more than 13 mm, and the spinal cord was impinged between the os odontoideum and the lamina of the axis in extension and reduced in flexion. In Group IIIB, Datl was less than or equal to 13 mm, and the spinal cord was compressed at the level of the atlas during flexion and extension. Stenotic Datl of 13 mm or less specifically defined severe cervical myelopathy. Surgical treatment for cervical myelopathy in os odontoideum with posterior instability is suggested as follows: in the absence of canal stenosis of the atlas (Group IIIA), atlantoaxial fusion in a reduced position is indicated; when associated with canal stenosis of the atlas (Group IIIB), laminectomy of the atlas followed by occiput-to-C2 arthrodesis is indispensable.

Adolescent↗
PubMed1991

Treatment of cervical spondylotic myelopathy by enlargement of the spinal canal anteriorly, followed by arthrodesis.

Thirty-seven patients who had enlargement of the spinal canal anteriorly and stabilization of the spine for cervical spondylotic myelopathy were followed for an average of forty-nine months (range, twenty-eight to seventy months). Myelography and computed tomographic myelography were performed preoperatively on all patients to determine the location and features of the areas of decompression. The canal was enlarged by discectomy; by subtotal corpectomy and removal of the anteromedial parts of the pedicles; or by removal of osteophytes or of the posterior longitudinal ligament, or both. Partial corpectomy and interbody arthrodesis was performed in nine patients; subtotal corpectomy, including removal of the posterior parts of the vertebral bodies and of the posterior longitudinal ligament, and strut bone-grafting, in fifteen patients; and subtotal corpectomy, with detachment of the remaining thin posterior parts of the vertebral bodies and of the posterior longitudinal ligament, and strut bone-grafting, in thirteen patients. Postoperatively, radiographic examinations, including myelography and computed tomographic myelography, were performed for thirty-six patients and magnetic resonance imaging, for twenty-eight. A satisfactory neurological result was obtained in twenty-nine patients. Atrophy of the spinal cord, as seen on preoperative computed-tomographic myelograms, was predictive of an unsatisfactory result of the decompression, as was weakness of the peroneal muscles. All but one of the thirty-seven patients had improved walking ability at the most recent follow-up examination: seventeen patients improved by 1 point; fourteen, by 2 points; four, by 3 points; and one, by 4 points. The remaining patient reverted to the preoperative status after an initial improvement. The ability to walk at the interim examinations was compared with that at the most recent examination; three patients had continuing improvement, while three others had deterioration. The main cause of deterioration was new spondylotic changes associated with stenosis of the spinal canal, occurring at the level of the disc just cephalad to the fused levels. We concluded that anterior decompression followed by a secure arthrodesis should be an extensive procedure for patients who have cervical spondylotic myelopathy, as determined preoperatively from a myelogram or computed tomographic myelogram. Excision of the vertebral bodies should also be wide and should include the anteromedial parts of the pedicles. The third or fourth cervical vertebra should be included in the arthrodesis prophylactically in patients who have stenosis of the spinal canal when either of these vertebrae is adjacent to the level of fusion.

Adult↗
PubMed1991

Esophagocutaneous fistula after anterior cervical spine surgery and successful treatment using a sternocleidomastoid muscle flap. A case report.

An esophagocutaneous fistula following anterior cervical fusion is rare. A 61-year-old man had cervical myelopathy because of ossification of the posterior longitudinal ligament of the cervical spine. Anterior decompression of the cervical spine and anterior fusion with strut bone grafting were performed. A second anterior fusion was done because the graft was dislodged after the patient fell out of bed one month after surgery. An esophagocutaneous fistula occurred three months after the second anterior surgery. One of the causes of this esophagocutaneous fistula was considered to be a pressure necrosis of the esophagus because of to projection of the bone graft. Conservative treatment, which consisted of wound drainage and intravenous administration of antibiotics, was tried but was unsuccessful. A good result was achieved by cancellous bone grafting, closure of the esophageal fistula, and transposition of a sternocleidomastoid muscle flap to the interspace between the esophagus and the cervical spine.

Cervical Vertebrae↗
PubMed1990

X-chromosome monosomy in the myelin-deficient rat mutant.

We have identified three examples of female Wistar rats exhibiting the tremor and seizures characteristic of the X-linked myelin deficiency (md) mutation, which is ordinarily seen only in males. Cytogenetic study of two of these animals has shown them to have 41 chromosomes instead of the normal 42. The missing chromosome was identified as an X chromosome by G-banding analysis. These animals thus have an XO genotype comparable to that in Turner's syndrome. Anatomically, one of the animals, which was studied in detail, showed no abnormality of the uterus, and the ovaries, although somewhat smaller than normal, were histologically indistinguishable from those in a normal female rat. No evidence of endocardial fibroelastosis was detected, nor was there any anomaly of the aorta. The myelin deficiency in the central nervous system was comparable to that in hemizygous mutant male rats. XO monosomy in the Wistar rat thus has little effect on phenotype and is more comparable to that in mice than to Turner's syndrome in man. The myelin-deficient rat is useful for studies of X-chromosome monosomy since XO females can readily be identified by the neurological syndrome characteristic of the md mutation.

Animals↗
PubMed1990

Myelin formation following transplantation of normal fetal glia into myelin-deficient rat spinal cord.

Structurally normal myelin sheaths develop in the spinal cord of juvenile myelin-deficient rats (mdr) 11 days after transplantation of normal fetal spinal cord fragments or cultured cells that do not yet express galactocerebroside. Cultures result in more extensive myelin formation, and in both cases the myelin that forms is located primarily at or near the site of transplantation. Myelin formation also occurs after transplantation of postnatal donor tissue, but the extent diminishes with donor age, and none was seen after transplantation of adult donor tissue over the two-week period studied. Injection of killed tissue, tissue derived from mouse donors or an extract of myelin also did not lead to myelin formation. The results imply that myelin formed in the host following transplantation was generated by oligodendrocytes newly differentiated from donor precursor cells rather than by donor oligodendrocytes that were already mature at the time of transplantation or by host oligodendrocytes that took up components of the injected material. We conclude that exogenous fetal glial cell precursors are able to survive, differentiate and form myelin in the environment of the juvenile mdr spinal cord.

Aging↗
PubMed1988

[Primary intracranial malignant melanoma associated with nevus of Ota: a case report].

A case of intracranial malignant melanoma associated with nevus of Ota is presented. A 77-year-old man was admitted to the department of neurosurgery, Fukui Medical School on June, 1985 because of developing disturbed consciousness. The physical examination on admission revealed pigmented lesion diagnostic of the nevus of Ota, anisocoria (R greater than L) and left hemiparesis. Computed tomographic (CT) scans demonstrated a high density mass in the left temporal lobe and the mass was homogenously enhanced after the injection of contrast agent. Left common carotid angiogram showed elevation of the middle cerebral artery and a slight vascular blush. Subtotal removal of the dark-colored tumor within the left temporal lobe and biopsy of the nevus were performed. Histopathological examination of the tumor revealed malignant melanoma and that of the skin biopsy was consistent with a nevus of Ota. Postoperatively DTIC, ACNU and vincristine were administered intravenously but the patient died three weeks after operation. At autopsy, widespread black pigmentation of the leptomeninges, communicating with the pigmented tumor in the left temporal lobe, covered the base of the brain and spinal cord. No melanoma was found outside the central nervous system. Primary intracranial melanoma associated with nevus of Ota is rare and only 6 cases have been reported in the literature. In this paper, primary intracranial melanoma associated with nevus of Ota and some other subjects are discussed.

Aged↗
PubMed1988

[Tissue culture study of meningioma and hemangiopericytoma].

Intracranial meningioma cells and hemangiopericytoma cells were cultured in vitro for immunohistological and ultrastructural study. Anti-vimentin, desmin, actin, alpha-actinin and laminin monoclonal antibodies were applied for immunohistological examination. Three dimension culture cells in collagen gel were examined by electron microscopy for ultrastructural studies. Cultured meningioma cells and hemangiopericytoma cells were positive for anti-vimentin stain, while desmin, actin, alpha-actinin were positive in only hemangiopericytoma cells. The culture morphology of these two cells was same in light microscopic study except for the whorl formation in meningioma cells. Reconstruction of intercellular junctions such as desmosomes and junctional complexes were common in cultured meningioma cells but seldom in hemangiopericytoma cells. Hemangiopericytoma cells continued to have prominent intracytoplasmic intermediate filaments and microfilaments forming dense bodies in culture. These results suggest that intracranial hemangiopericytoma has something in common with smooth muscle cell and fibroblast cells which forms the vascular and perivascular tissues, and it is distinguishable from meningioma.

Aged↗
PubMed1987

[A case of non-neoplastic pineal cyst presenting Parinaud's syndrome].

A case of non-neoplastic pineal cyst with Parinaud's syndrome is presented. A 54-year-old woman was admitted to the department of neurosurgery. Fukui Medical School on October, 1985, complaining of the paralysis of upward gaze. A computed tomography (CT) demonstrated a low density mass in the pineal region and the mass was not enhanced after the injection of contrast agent. Metrizamide CT cisternogram delineated the mass clearly. Bilateral carotid and vertebral angiograms showed no significant findings. On November 5, an operation was performed by means of an occipital transtentorial approach. A cyst filled with clear yellowish fluid was found in the pineal region. The cyst was evacuated and its wall was subtotally resected. The histological examination revealed the cystic cavity lined by fibrous astrocytes which were surrounded by normal pineal tissue. Therefore the cyst was diagnosed as a non-neoplastic pineal cyst. The postoperative course was uneventful. The paralysis of upward gaze was gradually improved. On December 27, the patient was discharged in excellent condition. Non-neoplastic small cysts which do not cause an enlargement of the pineal body are common incidental findings at autopsy, whereas large cysts which cause symptoms due to compression of the corpora quadrigemina and the production of internal hydrocephalus are rare. In this paper, non-neoplastic pineal cyst is discussed.

Brain Diseases↗
PubMed1986

[Cerebral blood flow studies using N-isopropyl I-123 p-iodoamphetamine in cerebral ischemic lesions].

Eighteen patients were studied for cerebral blood perfusion abnormalities using N-isopropyl I-123 p-iodoamphetamine (IMP) and rotating dual gamma camera emission computed tomography (ECT). All were stroke patients, 10 with cerebral vasospasm after an aneurysmal rupture, 3 with an occlusion of the middle cerebral artery, 2 with an occlusion of the internal carotid artery (IC), one with an IC stenosis, one with Moyamoya disease and one with RIND. Four patients had extracranial-intracranial (EC-IC) bypass operations. In three of them, CBF studies were done before and after bypass surgery. An arterial line was placed in the left radial artery and connected to a Harvard pump. IMP (1.5-3 mCi) was injected into an arm vein while at the same time an arterial blood sample was withdrawn at a constant speed for 5 minutes. Scanning was started 35 minutes after IMP injection. After a scan, multiple transverse, coronal and sagittal section images were reconstructed with a minicomputer. We determined the values of regional CBF in the regions of interest using an image. Transmission computed tomography (CT) studies were performed on the same day. In eight patients, CBF study by 133Xe inhalation method (NOVO cerebrograph) was done. ECT showed diffuse low perfusion in two patients and focal low perfusion in 16 patients while CT showed abnormalities in 9 patients (50%). ECT abnormalities were more extensive than CT abnormalities. The values of rCBF in the superficial brain determined by ECT were similar to those examined by the inhalation method (ISI). Significant increase in rCBF was observed after the bypass operations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Brain blood flow studies with single photon emission computed tomography in patients with plateau waves].

The authors studied brain blood flow with single photon emission computed tomography (SPECT) in two patients with plateau waves. The intracranial pressure and blood pressure were also monitored continuously in these patients. They included one patient with brain-tumor (rt. sphenoid ridge meningioma) and another with hydrocephalus after subarachnoid hemorrhage due to rupture of lt. internal carotid aneurysm. The intracranial pressure was monitored through an indwelling ventricular catheter attached to a pressure transducer. The blood pressure was recorded through an intraarterial catheter placed in the dorsalis pedis artery. Brain blood flow was studied with Headtome SET-011 (manufactured by Shimazu Co., Ltd.). For this flow measurement study, an intravenous injection of Xenon-133 of about 30 mCi was given via an antecubital vein. The position of the slice for the SPECT was selected so as to obtain information not only from the cerebral hemisphere but also from the brain stem: a cross section 25 degrees over the orbito-meatal line, passing through the inferior aspect of the frontal horn, the basal ganglia, the lower recessus of the third ventricle and the brain stem. The results indicated that, in the cerebral hemisphere, plateau waves were accompanied by a decrease in blood flow, whereas, in the brain stem, the blood flow showed little change during plateau waves as compared with the interval phase between two plateau waves. These observations may explain why there is no rise in the blood pressure and why patients are often alert during plateau waves.

Adult↗
PubMed1986

[Cockayne's syndrome presenting cerebral ischemic attack: case report].

A 29-year-old man with Cockayne's syndrome (CS), presenting reversible ischemic neurological deficit is reported. In his past history, hearing disturbance developed at 6 years old and visual disturbance at 12 years old. His parents have consanguinious marriage. He came to our hospital complaining of right-sided hemiparesis and speech disturbance. He was 115.8 cm tall and his weight 20 kg. The characteristic manifestation of CS, i. e., dwarfism, mental retardadation, cachectic feature, retinal atrophy, neural deafness and calcification of bilateral basal ganglia were all noticed. A CT scan on admission revealed marked brain atrophy as well as the intracranial calcifications, while no lesions compatible with his neurological findings were detected. Cerebral ischemic state was mostly suspected. Following up with conservative therapy by the use of fibrinolytic agent, his neurological deteriorations disappeared on the 4th hospital day. Cerebral angiograms showed stenotic lesions of both C1-C2 portion of the left internal carotid artery and the right middle cerebral artery, and the aneurysm in the right internal carotid artery. Such atherosclerotic vascular change as observed in the cerebral angiograms in this case have progressed rapidly for his age. In this case, diabetes mellitus and hyperlipoproteinemia such as increased total cholesterol, increased triglyceride, decreased HDL and increased apoprotein B and C II were complicated for the risk factor of the atherosclerosis. It's controversial that early progress of atherosclerosis is due to ideopathic original feature of CS or to the secondary change from these complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Intracranial pressure irregularities in experimental subarachnoid hemorrhage].

The intracranial pressure (ICP) irregularities, i.e., pressure waves, were studied in dogs with experimental subarachnoid hemorrhage. Animals were lightly anesthetised, immobilised with panchronium bromide and respirated artificially. Subarachnoid infusion of hemolysed red blood cells was used to induce intracranial hypertension. Recordings of both systemic blood pressure (SBP) and ICP were undertaken continuously. After the infusion of hemolysed blood the ICP increased gradually and reached to 50 mmHg or more at the terminal stage. The pressure waves were classified into two types, i.e., the fast waves and the slow waves. The fast waves had a duration of 10-30 seconds, being accompanied by a marked increase of the SBP. The slow waves gradually increased their frequency and the duration, when the ICP increased more than 20 mmHg or more resembling plateau-like waves. Postmorten examination showed hemogenic meningitis at the base of the brain, especially the medulla oblongata. The results suggest that studies of the slow waves is of value for analyzing plateau waves.

Animals↗