A shape-corrective shunt-passer using a titanium-nickel alloy.
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Alloys↗
Biomedical subjects
S Oi
Publications and source records attributed to S Oi.
Determination of effector molecules in L-arabinose-induced bulge formation and lysis of Escherichia coli IFO 3545.
L-Ribulose 5-phosphate (L-Ru5P) was identified as the primary effector molecule of L-arabinose-induced bulge formation in Escherichia coli IFO 3545 observed in nutrient broth with 5% (w/v) sodium chloride. Hyperinduction of L-arabinose isomerase was due to exogenous sodium chloride and the resulting alteration in the balance of the L-arabinose-metabolizing enzymes resulted in accumulation of L-Ru5P. L-Ru5P induced the lysis of an L-arabinose-negative, L-Ru5P 4-epimerase-less mutant, ara-207, even when directly added to the medium but was not active against the wild-type strain. Some L-arabinose-utilizing (L-arabinose-resistant) revertants of ara-207 were still sensitive to L-Ru5P, indicating the involvement of another mutation in L-Ru5P-sensitivity other than genetic lack of L-Ru5P 4-epimerase. Among the various pentose phosphate esters tested, only L-Ru5P could induce lysis of ara-207. The lytic activity of L-Ru5P was attributed to its effect on bacterial sugar nucleotide metabolism which caused secondary accumulation of uridine 5'-diphosphate galactose (UDPGal), which provoked lysis induction.
Arabinose↗
Studies on antidiabetic agents. X. Synthesis and biological activities of pioglitazone and related compounds.
Various analogues of a new antidiabetic agent, pioglitazone (AD-4833, U-72107), were synthesized in order to study in more detail the structure-activity relationships of this class of drug. 5-(4-Pyridylalkylthiobenzyl)-2,4-thiazolidinediones (I), thia-analogues of pioglitazone, were prepared via Meerwein arylation of the alkylthioanilines (IV). 5-(4-Pyridylalkoxybenzylidene)-2,4-thiazolidinediones (IIa) and related heterocyclic analogues (IIb) were synthesized by Knoevenagel condensation of the aldehydes (VIII) with the corresponding azolidinones. Compounds I and II were evaluated for hypoglycemic and hypolipidemic activity in genetically obese and diabetic yellow KK (KKAy) mice. Several 5-[4-[2-(2-pyridyl)ethoxy]-benzylidene]-2,4- thiazolidinediones (IIa) were equipotent to pioglitazone. However, the thia-analogues (I) and the benzylideneheterocycles (IIb) had decreased activity. Catalytic hydrogenation of the 5-benzylidene analogue (14) was found to be a convenient new synthetic method for pioglitazone. The configuration of 14 is also discussed.
Animals↗
Congenital hydrocephalus mimicking Dandy-Walker syndrome induced by 6-aminonicotinamide injection in pregnant rat.
Fetal hydrocephalus was induced by single intraperitoneal injection of 8 mg/kg 6-aminonicotinamide (6-AN), a niacinamide antagonist, in Sprague-Dawley rat on day 13 of gestation. Materials for histological examination were obtained by uterotomy 1, 2, 4, and 8 days after injection, and untreated fetuses of the same ages were used as controls. Macrocephalus was clear at day 17 (4 days after injection), when cerebral dysgenesis was suggested by bromodeoxyuridine immunohistochemical study. The entire ventricular system was dilated, including the aqueduct and foramen of Monro, and hypoplasia of the cerebellum was also observed. On day 21, macrocephalus was remarkable, and considerable hypoplasia of the choroid plexus and cerebellum and agenesis of the corpus callosum were recognized. These results indicate that this experimental hydrocephalic model associated with various central nervous system anomalies mimics human Dandy-Walker syndrome, suggesting the pathogenesis of Dandy-Walker syndrome to be a feature of systemic metabolic deficits.
6-Aminonicotinamide↗
Hydromyelic hydrocephalus. Correlation of hydromyelia with various stages of hydrocephalus in postshunt isolated compartments.
The clinical features and pathophysiology of specific forms of hydromyelia are analyzed in this report together with the chronological changes of associated hydrocephalus. Nine patients were studied; all had hydromyelia with varying degrees of associated hydrocephalus. Clinically applicable classification systems were used to evaluate the progression of hydrocephalus (Stages I to IV) and to define the compartment isolated after shunting in the previously communicating cerebral ventricles (Types I to IV). Four patients had Stage IV disease (holoneural canal dilatation); one had Stage II and four had Stage I disease (both Stages I and II with supratentorial hydrocephalus). All patients were initially treated by ventriculoperitoneal shunting at an average age of 9.9 years. Five patients had progressive spinal symptoms before or after treatment of their hydrocephalus. Two patients had Type III isolation (an isolated rhombencephalic ventricle) with a functioning ventricular shunt; ventriculography confirmed a communication between the fourth ventricle and the hydromyelia, and both patients improved after placement of a shunt in the fourth ventricle. The remaining patients had Type IV isolation (isolated central canal dilatation) with a functioning ventricular shunt. This study indicates that in some cases the pathophysiology of hydromyelia is closely related to associated hydrocephalus. A new concept of the development of an isolated compartment after shunting is proposed to explain the progression of hydromyelia in these cases.
Adolescent↗
Pathophysiology and postnatal outcome of fetal hydrocephalus.
At the National Kagawa Children's or Kobe University Hospital, 24 cases of fetal hydrocephalus were managed between 1982 and 1988. There were 8 simple, 11 dysgenetic, and 5 secondary cases of hydrocephalus, and the fetal age at diagnosis ranged between 24 and 40 weeks of gestation (average 33.4 weeks). All were diagnosed using ultrasonography, with either magnetic resonance imaging or whole-body computed tomography, additionally performed in 10 patients to determine their usefulness in evaluating the morphology. Four patients underwent transabdominal or transvaginal cephalocentesis in the prenatal period and intracranial pressure was measured during the drainage of cerebrospinal fluid in two of these. Postnatal outcome was analyzed for each type of hydrocephalus. The results suggested that in such cases the fetal brain is subjected to extremely high intracranial pressures resulting from a mixture of hydrocephalic pressure and intermittent uterine constriction. Immediately after birth, the biparietal diameter was found to be increased by an average of 7.7 mm and the hydrocephalic state was transformed into the neonatal type characterized by macrocephaly and a relatively low intracranial pressure. Overall mortality was 25% and 16 of the 24 infants underwent the postnatal shunt procedure, largely at the neonatal stage. The follow-up period varied from 4 months to 6 years (average, 25.8 months for nonfatal cases) and the mean intelligence or developmental quotient was 45.2. There were no significant differences in postnatal outcome between the three major types of fetal hydrocephalus. Findings revealed that the length of the gestation period after the diagnosis of hydrocephalus has a significant effect on outcome (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Cerebrospinal Fluid Shunts↗
Morphological evaluation for neuronal maturation in anencephaly and encephalocele in human neonates. A proposal of reclassification of cephalic dysraphism.
The developmental pathogenesis of cranium bifidum and exencephaly, as well as other forms of the dysraphic state, remains unresolved. The process of neuronal maturation under such conditions is the major definitive factor for functional prognosis and may be the key to the embryopathogenesis. The neuronal maturation processes in cranium bifidum and anencephaly were analyzed in both human neonatal autopsy and surgical specimens, utilizing the technique of immunohistochemical morphological analysis. The results suggest that anencephaly is a form of neuroschisis, a defect in which the neuronal developmental process arrests and results in dys- or rather aplastic cortical architecture. In contrast, although the cortical architecture is often distorted, neuronal maturation in cases of cranium bifidum cysticum is primarily complete, demonstrating normal cerebral cortical layers and NSE positive neural elements. In conclusion, it is strongly suggested that anencephaly is the most severe form of cranium bifidum, as is myeloschisis in spina bifida, without supportable neuronal maturation. Recognizing these points in the developmental stages with regard to the degree of neuronal maturation, a reclassification of cephalic dysraphism is proposed. The embryopathogenetic and epidemiologic aspects of this proposal of reclassification are discussed.
Anencephaly↗
Massive congenital intracranial teratoma diagnosed in utero.
The authors describe a case of congenital intracranial teratoma. The patient was diagnosed to be hydrocephalic at 29 weeks' gestation, and to have a huge intraventricular mass lesion at 34 weeks' gestation. Subsequently, the patient underwent subtotal resection of the mass, resulting in a significant decrease in the remarkably elevated alpha-fetoprotein in serum and cerebrospinal fluid. Histological analysis revealed a malignant teratoma, also with alpha-fetoprotein-positive elements in the immunohistochemical study.
Brain Neoplasms↗
Ependymoma diagnosed in the first year of life in Japan in collaboration with the International Society for Pediatric Neurosurgery.
During 1987, 23 survey forms for ependymoma cases diagnosed in the 1st year of life were selected from 88 neurosurgical institutes in Japan in collaboration with the International Society for Pediatric Neurosurgery. There were no specific perinatal episodes. The most common clinical manifestations were symptoms of intracranial hypertension and hydrocephalus. Two of seven children with infratentorial ependymomas were alive, and all of the children with such supratentorial tumors were still alive. Of those with ependymoma, three of four in the total extirpation group, and three of seven in the subtotal or partial removal group were alive. The 1-year survival rate was 54% for ependymoma and 58.3% for ependymoblastoma. For 36% of the cases with ependymoma and 14.6% with ependymoblastoma, a 2-year survival rate was observed. Since the prognosis of these tumors is poor, they should be extirpated as often as possible. Collins' law held true in approximately half of the cases.
Brain Neoplasms↗
Tethered cord syndrome versus low-placed conus medullaris in an over-distended spinal cord following initial repair for myelodysplasia.
We present findings obtained from a total of 100 patients who had previously undergone surgery for spina bifida and whose progress had been monitored by magnetic resonance imaging (MRI) in our meningomyelocele clinic. Fourteen of these patients (14.0%) developed delayed symptom(s) of progressive spinal neurologic dysfunction. In those with myeloschisis, increase of motor deficit was the most common clinical manifestation during infancy and early childhood (mean age: 6.8 years), whereas pain on back flexion was seen in patients who were over 15 years of age (mean age: 17.3 years). MRI carried out in myeloschisis patients invariably demonstrated that the conus medullaris was in an abnormally low position, suggesting over-distension of the spinal cord. This was irrespective of whether symptom(s) developed or not and did not correlate with the initial surgical procedure (reconstructive or otherwise) used. Patients with symptom(s) were revealed by MRI to have an extremely low conus set at the spinal level of S-1 or below; neurological examinations showed that the motor deficit occurred at high levels in the spine. Results from lipomeningocele patients were more erratic in terms of conus position and delayed development of neurological defects.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Brain tumors diagnosed in the first year of life in five Far-Eastern countries. Statistical analysis of 307 cases.
A statistical survey is presented of brain tumors diagnosed in the first year of life (from five Far-Eastern countries) in relation to the racial differences in tumor types, congenital factors, and general clinical features. Of the 307 cases collected, 262 were verified histologically, and astrocytomas comprised 23.3%, medulloblastomas 17.2%, ependymomas 11.1%, choroid plexus papillomas 10.7%, teratomas 8.4%, primitive neuroectodermal tumors 4.2%, meningiomas 2.3%, and others 22.9%. There were statistically significant racial differences in comparison with the worldwide survey done by the International Society for Pediatric Neurosurgery Education Committee (1987) on the same subject. In the Far-Eastern population, medulloblastoma and teratoma were more common (P less than 0.05), whereas astrocytoma was less frequent (P less than 0.01) than reported in the worldwide survey. The malformative factors were suggested in 18 cases in which various associated congenital anomalies were observed. Vascular anomalous lesions, mostly in the extracranial organs, were most common, comprising 61.1% of the associated malformations. Hereditary factors were less commonly demonstrated in these tumors than were anomalies in the major congenital central nervous system. Among the 307 cases, there was one instance (0.3%) of nearly identical tumors occurring in twin brothers. The specific clinical manifestations of brain tumors involving the immature brain were again apparent in this survey, as were the poor survival rates and poor functional prognosis.
China↗
Congenital brain tumors in Japan (ISPN Cooperative Study): specific clinical features in neonates.
The authors present specific clinical features of brain tumors occurring in immature brain in comparison with those of older infants and children. Twenty-six neonatal brain tumors, which accounted for 11.3% of 231 brain tumors diagnosed in the 1st year of life collected in a cooperative study in Japan, were analyzed. Although astrocytomas were invariably common tumors in each age group, comprising 25.0% for all pediatric brain tumors, teratomas were the most common type of neonatal brain tumors and accounted for 33.4% in this age group. Location of tumors in the immature brain was more striking, involving the posterior fossa region less commonly, as in 11.1% in neonatal, 29.5% in infantile, and 41.4% in all pediatric age groups. Surgical intervention was performed in 97.4% of the infantile and 79.1% of the neonatal cases, but total or subtotal resection of the mass was achieved only in 58.9% in the infants and 73.7% in the neonates. There was more strict limitation in performing the adjuvant therapies in the immature age groups. Radiation therapy and chemotherapy were given only in 32.0% and 27.6%, respectively, in the neonatal cases. The prognosis was extremely poor in the immature cases: 1-year, 5-year, and 10-year survival rates were 59.3%, 26.1%, 11.5% in the infants, and 43.5%, 23.8%, 7.1% in the neonates, respectively. Of the neonates, 76% and of the infants 73.1% were retarded. The present study delineates the characteristic clinical features of tumors involving immature brain and emphasized that establishment of more specific therapeutic modalities is urgent.
Brain Neoplasms↗
Radiation-induced brain damage in children--histological analysis of sequential tissue changes in 34 autopsy cases.
The nature and sequence of the radiation-induced changes in the brain were studied postmortem in 34 children with glioma, 22 of whom underwent central nervous system radiation therapy. Twenty received whole-brain or whole-neuroaxis radiation at a total mean dosage of 4063 cGy. Brain tissue alterations were analyzed histologically by means of various staining methods, including immunohistochemical techniques. The histological features of irradiated brains were compared with those of non-irradiated brains. Microscopic findings included demyelination (seven cases), focal necrosis (six cases), cortical atrophy (four cases), endothelial proliferation (four cases), and telangiectatic vascular proliferation with vascular thickening and oozing of a thick fluid (one case). Such findings were rare in non-irradiated patients. Demyelination was observed earliest in a patient who died 5 months after radiation therapy and was more common after 9 months. Focal necrosis was first observed 9 months post-irradiation but was more advanced and extensive after 1 year. Calcified foci were found only after 60 months. Various vascular changes such as vascular thickening and thrombosis suggested ischemic insult to the brain as a late effect of radiation injury. The results of this study suggest that the immature brain may be more sensitive to radiation than is the adult brain, and that the manifestations of radiation-induced injury depend on the time elapsed after irradiation.
Adolescent↗
Identical embryopathogenesis for exencephaly and myeloschisis: an experimental study.
Extensive histological and immunohistochemical studies were performed to elucidate the histopathogenesis of exencephaly induced in chick embryo as an experimental model. The findings were compared with those identified in a chick myeloschisis experimental model and in human autopsy cases. The experimental model of exencephaly in chick embryos was developed by induction with various teratogens including ethylnitrosourea, salicylate, and phenytoin. None of the cases of exencephaly was exposed to a teratogen prior to or within Hamburger and Hamilton stage 12 (45 to 49 hours postincubation), when the anterior neuropore closes. The process of overgrowth in development of exencephaly was identical to that of myeloschisis, and the results suggested neuronal overmaturation in the histological and immunohistochemical studies. Although the late-stage degenerative change with neovascularization over the exposed neural tissue (placode) was more severe in human exencephaly, the present experimental study may suggest a possible common embryopathogenesis of dysraphism. Exencephaly should be regarded as the most severe form of cranium bifidum, as myeloschisis is in spina bifida.
Animals↗
Hydrocephalus in premature infants. Characteristics and therapeutic problems.
Twenty-one premature infants with various underlying conditions developed hydrocephalus. The characteristic clinical pictures as well as the therapeutic problems are discussed. The causative underlying conditions included intraventricular hemorrhage in the neonate or fetus, broncho-pulmonary dysplasia, congenital malformations such as holoprosencephaly with chromosome anomalies, and others. The pathophysiological aspects were considered to be characterized by the underdevelopment of major cerebrospinal fluid pathway, extremely high intracranial compliance, and demyelinating process of the nervous system. The shunt problems in these patients with such low body weight were also unique, showing an extremely high incidence of postshunt hydrocele, shunt migration into the scrotum, shunt malfunction, slit-like ventricle, and isolated ventricles. Intensive management, combined with better control of the hydrocephalus with these concepts, will help to improve the long-term outcome of these premature infants.
Abnormalities, Multiple↗
Effect of liver disease on the kinetics of lactate removal after heavy exercise.
Recovery from heavy exercise requires clearance of lactic acid from the blood and body tissues. Although it has long been felt that the liver plays the major role in lactate removal, it has more recently been asserted that skeletal muscle plays the dominant role. We felt it relevant to this controversy to determine whether patients with liver dysfunction have slowed lactate removal following heavy exercise. Eight patients with alcoholic liver disease and 5 normal subjects were studied. Liver function was measured by the 14C-aminopyrine breath test; the results were expressed as the rate of appearance of 14CO2 in the breath two hours after ingestion, as a fraction of the ingested 14C dose (%.h-1). Each participant exercised on a cycle ergometer for 7 min at a work rate which was moderately heavy for that subject (mean peak lactate is 5.3 mmol.L-1). During, and for 45 minutes after exercise, blood was drawn from a hand vein catheter. The time required for blood lactate to decrease halfway toward resting levels (t1/2 LA) was determined. Compared to the normal subjects and historical controls, seven of the patients had distinctly slowed lactate removal. The t1/2 LA was as long as 46 min (as compared to approximately 15 min seen normally). Further, among the patients the 2 h breath excretion of 14C was well correlated with the rate constant of lactate removal (r 0.82, P less than 0.01). Four of the patients with severe liver dysfunction performed a second exercise test in which, instead of resting after heavy exercise, low level exercise was continued. The t1/2 LA of the averaged responses decreased by 29%.2+
Adult↗
[Diffuse axonal injury manifested as corpus callosum damage on magnetic resonance imaging. Case report].
A 26-year-old male was injured in a motorcycle accident and arrived unconscious at a local general hospital. Lack of improvement despite intensive care prompted his referral to the neurosurgical department, approximately 10 hours after the accident. On neurological examination his Glasgow Coma Scale score was 8, and mild right hemiparesis and right radial nerve palsy were noted. There was no skull fracture. Computed tomography disclosed intraventricular hemorrhage and small hemorrhagic foci in the prepontine area and the border between the gray and white matter. No hemorrhage was demonstrated in the corpus callosum. Magnetic resonance imaging (MRI) was performed 3 weeks after admission with a 0.5-tesla resistive Vista magnetic resonance scanner. The inversion recovery technique was used, with a repetition time (TR) of 2100 msec, an inversion time of 500 msec, and an echo time (TE) of 40 msec, for T1-weighted images. The spin-echo technique was used, with a TR of 2000 msec and a TE of 80 msec, for T2-weighted images. In the body and splenium of the corpus callosum, T1-weighted images showed a spotty area of low signal intensity with an irregular margin; this area was of high signal intensity on T2-weighted images. On repeat MRI performed 4 months after injury, T1-weighted images showed, in the same region, granular low signal intensity, while T2-weighted images showed high signal intensity. The MRI findings in the subacute and chronic stages of diffuse axonal injury are discussed.
Adult↗
Immunohistochemical evaluation of neuronal maturation in untreated fetal hydrocephalus.
The prognosis of fetal hydrocephalus is poor and the results of intrauterine decompression have so far been unsatisfactory. Although several factors have been known to affect the prognosis of intrauterine hydrocephalus, few histological studies of preterm hydrocephalus and no immunohistochemical analyses have been reported to date. In eight fetal cases of untreated preterm hydrocephalus, the authors morphologically studied neuronal maturation by means of immunohistochemical and specific myelin staining techniques. The patients' gestational ages at death ranged from 20 to 40 weeks (mean, 30 weeks). There were two cases of simple form of hydrocephalus, two of cerebral dysgenesis (hydranencephaly and holoprosencephaly), and four of hydrocephalus secondary to intraventricular hemorrhage. Relatively primitive neuronal developmental processes, such as neuronal cell proliferation and migration, were found to be altered by rapidly progressive simple form of intrauterine hydrocephalus, whereas the neuronal maturation disorder was obviously the primary condition in dysgenetic hydrocephalus. Hydrocephalus itself, however, caused additional damage in the presence of delayed but slowly progressing neuronal development. Secondary hydrocephalus initially reflects impairment of previously normal neuronal maturation. In this situation, too, hydrocephalus per se further compromised the potential for continued neuronal development. The results of this study imply that the pathoembryological concepts of fetal hydrocephalus are not so simple. Early decompression may preserve the potential for further neuronal maturation in fetal hydrocephalus.
Fetal Diseases↗