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Biomedical subjects

S Oi

Publications and source records attributed to S Oi.

At least 37 records · Page 2Linked to original sources
PubMed1999

Delayed ischemic neurological deficit of short duration in patients with subarachnoid hemorrhage.

We retrospectively examined the duration of delayed ischemic neurological deficits (DIND) attributed to vasospasm following subarachnoid hemorrhage (SAH) in order to delineate the nature and involved factors. Among 605 patients with SAH, 201 developed DIND, and 137 of these had undergone early aneurysmal obliteration. In these 137, duration of DIND was clearly determined in 67 cases. Hypervolemic therapy was instituted only after the onset of DIND. In the 67 patients, the mean duration of DIND was 5.2 days (ranging from 2 to 13 days); 22 patients had DIND lasting only 2 to 3 days, 26 patients had DIND lasting 4 to 6 days, and in 19, DIND lasted 7 to 13 days. Clinical factors associated with short DIND duration (2 to 3 days) as determined by multivariate analysis included internal carotid artery or middle cerebral artery aneurysm, age under 60, and a good World Federation of Neurological Surgeons grade on admission. No patients developed pulmonary edema from hypervolemic therapy, and the outcomes of all 67 patients were extremely favorable. In SAH patients developing DIND after early aneurysmal surgery, 16% (22 of 137) had a documented brief duration of DIND. We believe DIND rapidly improved and resolved with hypervolemic therapy because antecedent brain damage from SAH or surgical manipulation had been minimal.

Female↗
PubMed1998

Synthesis of peptide aldehyde derivatives as selective inhibitors of human cathepsin L and their inhibitory effect on bone resorption.

Cathepsin L, a lysosomal cysteine protease, is secreted by osteoclasts and participates in bone collagen degradation. In a search for cathepsin L inhibitors as antiosteoporotic agents, a series of peptide aldehyde derivatives were prepared by two synthetic approaches, DMSO oxidation of the corresponding alcohol derivatives and DIBAL-H reduction of the corresponding N, O-dimethylhydroxylamide derivatives, and evaluated for inhibitory activity against human cathepsin L and for inhibitory effects on bone resorption. Some of the peptide aldehyde derivatives including alpha-acylamino aldehyde derivatives showed potent activities. Among these compounds, N-(1-naphthalenylsulfonyl-L-isoleucyl-L-tryptophanal (12) was selected as a candidate for further investigation. Compound 12, a potent, selective, and reversible inhibitor of human cathepsin L with an IC50 of 1.9 nM, inhibited the release of Ca2+ and hydroxyproline from bone in in vitro bone culture system and also prevented bone loss in ovariectomized mice at an oral dose of 50 mg/kg.

Aldehydes↗
PubMed1998

Sinusoidal intrathecal infusion for assessment of CSF dynamics in kaolin-induced hydrocephalus.

OBJECTIVE: To evaluate whether changes of CSF outflow resistance and compliance in hydrocephalus can be assessed by an intrathecal infusion which is performed at a sinusoidal varying rate. METHODS: Hydrocephalus was produced in 10 Sprague Dawley rats by instillation of 0.0375 g of kaolin in 0.9% saline into the cisterna magna. Measurements were performed 4 weeks later: With each animal both, three successive constant rate infusions (0-0.02 ml/min) and a sinusoidal infusion (0-0.02 ml/min, frequency 0.006 Hz) were performed. 6 normal animals served as control. The pressure recordings of both infusion techniques were used for the assessment of the CSF outflow resistance. The time constant and the pressure volume index were calculated only from the sinusoidal input testing. RESULTS: The sinusoidal test as well as the constant rate infusion both demonstrated a severe impairment of CSF absorption. By the sinusoidal input, a decreased compliance was confirmed additionally. Thus, the sinusoidal infusion test demonstrated a high resistance and low compliance hydrocephalus in the kaolin-treated group. A simple graphical procedure is presented which allows an easy assessment of CSF dynamics by the sinusoidal infusion test.

Animals↗
PubMed1998

Pressure-induced expression of heat shock protein 70 mRNA in adult rat heart is coupled both to protein kinase A-dependent and protein kinase C-dependent systems.

BACKGROUND: Production of heat shock protein 70 (HSP70) in the heart is induced by hemodynamic stress, but its intracellular signal transduction system has not been elucidated well. OBJECTIVE: To investigate the hypothesis that protein kinase A (PKA)-dependent and protein kinase C (PKC)dependent systems are involved in the pressure-induced expression of HSP70 mRNA in perfused adult rat heart METHODS: Isolated tetrodotoxin-arrested Sprague-Dawley rat hearts were perfused as Langendorff preparations at a constant aortic pressure of 60 mmHg. Aortic pressure in rats of the pressure-overloaded group was elevated from 60 to 120 mmHg for 2-120 min. cAMP contents and rates of synthesis of protein were measured by radioimmunoassay and the incorporation of [14C]-phenylalanine into total heart protein, respectively. Expression of HSP70 mRNA was determined by Northern blot analysis. RESULTS: Elevation of aortic pressure significantly increased cAMP content after 2 min of perfusion (by 41%), significantly increased rates of synthesis of protein during the second hour of perfusion (by 41%), and induced expression of HSP70 mRNA maximally after 60 min of perfusion (2.7-fold the control value). Exposure to glucagon, forskolin or 1 -methyl-3-isobutylxanthine mimicked increases in these parameters caused by elevation of aortic pressure. Administration of a selective PKA inhibitor, H-89, significantly prevented induction of increases in expression of HSP70 mRNA and rates of synthesis of protein by a high pressure overload and exposure to agents that increase cAMP content. Furthermore, administration of phorbol ester induced expression of HSP70 mRNA. Administration of a PKC inhibitor, calphostin C, significantly prevented induction of increases in expression of HSP70 mRNA by a pressure overload and by exposure to phorbol ester. CONCLUSIONS: These results suggest that the pressure-induced induction of production of HSP70 is regulated both by PKA-dependent and by PKC-dependent systems during periods of active synthesis of protein in adult rat heart.

1-Methyl-3-isobutylxanthine↗
PubMed1998

Intrauterine high-resolution magnetic resonance imaging in fetal hydrocephalus and prenatal estimation of postnatal outcomes with "perspective classification".

OBJECT: It is possible to diagnose hydrocephalus prenatally based on the morphological appearance of the fetus on neurodiagnostic images; however, the prognosis of this disease shows wide variation. The authors previously proposed a classification system for the prediction of postnatal outcome based on progression of hydrocephalus and affected brain development, known as the "Perspective Classification of Congenital Hydrocephalus (PCCH)." In this study the authors have used their classification system to analyze long-term follow-up results obtained in each clinicoembryological stage of fetal hydrocephalus. METHODS: Sixty-one fetuses with hydrocephalus were examined to predict postnatal outcome by using this newly developed classification. The authors' recently developed method of using heavily T2-weighted imaging with a superconducting magnet clearly delineated the cerebrospinal fluid (CSF) space and the malformed brain and spinal cord. Imaging was achieved in less than 1 second per slice and required no sedation of the fetus. The technique appears to be simple and good at delineating intrauterine anatomy. Hydrocephalus was diagnosed in two fetuses at PCCH embryological Stage I (8-21 gestational weeks), in 28 fetuses at Stage II (22-31 weeks), and in 31 fetuses at Stage III (32-40 weeks). Among these 61 fetuses, clinicopathological typing showed that 19 had primary hydrocephalus (nine in Stage II and 10 in Stage III), 34 had dysgenetic hydrocephalus (two in Stage I, 16 in Stage II, and 16 in Stage III), and eight had secondary hydrocephalus (three in Stage II and five in Stage III). When the hydrocephalic state developed during PCCH Stage I or II, the prognosis was very poor, and only one of 18 fetuses with dysgenetic hydrocephalus and none of three fetuses with secondary hydrocephalus had an acceptable postnatal outcome. Even within the same category or subtype of fetal hydrocephalus, such as primary hydrocephalus in its simple form, or hydrocephalus with spina bifida aperta (myeloschisis), the postnatal outcomes differed depending on the time of onset of hydrocephalus. When the diagnosis of hydrocephalus was made during PCCH Stage II, the fetuses had a poorer postnatal outcome compared with those at Stage III (p < 0.05). CONCLUSIONS: It is emphasized that postnatal prognosis is not simply a function of the form of the diagnosis but is also dependent on the progression of hydrocephalus and the degree to which that process affects neuronal development. Early decompressive procedures, conventionally performed after but, hopefully, performed before birth, are indicated to obtain the optimal postnatal prognosis of fetuses with hydrocephalus diagnosed at PCCH Stage II.

Disease Progression↗
PubMed1998

[Delayed ischemic neurological deficit that developed over 15 days after subarachnoid hemorrhage].

We retrospectively studied subarachnoid hemorrhage (SAH) patients with delayed ischemic neurological deficit (DIND), and analyzed the factors causing extremely late onset of deficits occurring over 15 days after onset of the SAH. Among 605 patients with SAH, 201 (33%) developed DIND. Among DIND patients, 137 had undergone early aneurysm surgery. In these 137 patients, onset date of DIND was definite in 131 patients. Six patients (5%) developed DIND over 15 days after SAH. All 6 had asymptomatic angiographical vasospasm and infections, most often meningitis, before the onset of DIND. Compared with cases in which there was ordinary onset of DIND, other statistically significant factors among these 6 patients were intracerebral hemorrhage, sepsis and meningitis. We suspect that DIND were manifested subclinically in the early period because of the associated hyperdynamic hemodynamics resulting from sepsis in these patients.

Adult↗
PubMed1997

Spontaneous reduction of a recurrent craniopharyngioma in an 8-year-old female patient: case report.

OBJECTIVE AND IMPORTANCE: The spontaneous rupture of a craniopharyngioma is an extremely rare condition confined to adults. This is the first report of a patient younger than 10 years who experienced spontaneous reduction (possibly rupture) of a craniopharyngioma. CLINICAL PRESENTATION: An 8-year-old female patient with a recurrence of a craniopharyngioma experienced fever, headache, and visual disturbance that lasted a few days. Concurrent with the improvement of these symptoms, marked reduction in the size of the tumor was revealed using magnetic resonance imaging, suggesting the occurrence of a rupture. INTERVENTION: Subsequent magnetic resonance imaging of the hypothalamic-pituitary region was performed while the patient received growth hormone therapy. CONCLUSION: There was no increase in the size of the tumor 1 year after the reduction occurred. Prompt evaluation of the hypothalamic-pituitary region using magnetic resonance imaging is warranted to rule out the possibility of spontaneous reduction (including rupture) of the tumor in a situation in which the patient with a craniopharyngioma shows meningeal signs or a rapid change of neurological symptoms (such as headache, fever, or visual disturbance).

Adult↗
PubMed1996

Evidence for farnesol-mediated isoprenoid synthesis regulation in a halophilic archaeon, Haloferax volcanii.

Farnesol strongly inhibited growth of a halophilic archaeon, Haloferax volcanii, with an IC50 value of only 2 microM (0.4 microgram/ml) in rich medium and 50 nM (0.01 microgram/ml) in minimal medium without lysis. Other isoprenoid alcohols such as isopentenol, dimethylallyl alcohol, geraniol, and geranylgeraniol at 500 microM did not affect its growth. Mevalonate, which is the precursor of all isoprenoid membrane lipids in archaea, led to recovery of the growth inhibition of H. volcanii, but acetate had no such effect. Farnesol inhibited incorporation of acetate, but not mevalonate, into the lipid fraction. These results suggest that farnesol inhibited the biosynthetic pathway from acetate (acetyl-CoA) to mevalonate. Farnesol is known to be derived from the important intermediate of isoprenoids, farnesyl diphosphate (FPP), and found in neutral lipid fraction from this archaeon. Moreover, the cell-free extracts from H. volcanii could phosphorylate farnesol with ATP to generate farnesyl monophosphate and FPP. We conclude that farnesol-mediated isoprenoid synthesis regulation system by controlling farnesol concentration is present in H. volcanii.

Acetates↗
PubMed1996

Neurovascular developmental interaction: a specific form of vascular maldevelopment in the malformed brain. I. An experimental study and proposal of a new teratological concept.

The process of the development of the intracranial vessels was studied by means of immunohistochemical analysis of factor VIII in normal and exencephalic chick fetuses. The results revealed that the development of blood vessels in exencephalic brain was far advanced beyond the norm, with intense immunoreactivity to factor VIII on postincubation day 16 exceeding that on day 21 in normal controls. Compared with results regarding the direction of the overgrowth in the neuronal maturation process in the previous study using the chick exencephaly model, the findings of overmatured blood vessels were compatible with NSE- and somatostatin-positive elements that appeared especially in the overgrowth foci. The results of the present study suggested the pathogenic development of the "area cerebrovasculosa" in the neural placode as a phenomenon consequent upon hypervascularization in response to neuronal overgrowth, as seen in human cases of exencephaly or anencephaly. We emphasize the significance of this specific phenomenon in the development of the fetal central nervous system, namely neurovascular developmental interaction.

Animals↗
PubMed1996

Experimental models of congenital hydrocephalus and comparable clinical problems in the fetal and neonatal periods.

Morphological and developmental changes of the ventricular system are analyzed in three major experimental models of congenital hydrocephalus in the rat: 6-aminonicotinamide (6-AN)-induced and LEW/Jms and HTX mutant hydrocephalus. The clinically comparable forms of hydrocephalus and problems occurring during each period of intrauterine hydrocephalus are then discussed. Comparative morphological study revealed that 6-AN-induced hydrocephalus was comparable to the Dandy-Walker syndrome and that the critical period regarding this syndrome in fetal life was at the time of "legal termination". The LEW/Jms and HTX mutant models were identical with regard to the form of progressive hydrocephalus in the postnatal period, but the condition underlying the hydrocephalus during the fetal period differed. The LEW/Jms model was comparable to primary congenital aqueductal stenosis (aqueductal agenesis), and the hydrocephalic state appeared in the period of "intrauterine preservation" before pulmonary maturation was completed. On the other hand, the HTX fetuses demonstrated secondary change of the aqueduct in the perinatal period, although the model was considered to be of congenital communicating hydrocephalus. Cerebrospinal fluid (CSF) dynamics studied in the fetuses with 6-AN-induced hydrocephalus disclosed considerable pathophysiology comparable to "hydromyelic hydrocephalus." The historical trends of animal experimental models of congenital hydrocephalus are reviewed and comparable clinical problems suggested by those models discussed further.

6-Aminonicotinamide↗
PubMed1996

Neurological and medico-social problems of spina bifida patients in adolescence and adulthood.

Chronological changes in the neurological manifestations of spina bifida are well recognized in the early developmental periods: fetal, neonatal, infantile, pre-school and school life. However, little has been written about the medical and medico-social problems of spina bifida patients in adulthood. Patients now in this age group had the condition diagnosed and managed in an era when modern neurosurgical concepts were only just beginning to be established with the aid of invasive methodology. In our series of 141 cases of spina bifida, 18 patients (13.5%) were over 16 years of age. These included 9 cases each of spina bifida aperta (myeloschisis) and spina bifida occulta (spinal lipoma). The ages ranged from 16 to 47 years (mean: 23.5 years) in the former and from 16 to 57 years (mean: 29.2 years) in the latter group. During the long-term follow-up with quantitative analysis of the spinal neurological changes using the spina bifida neurological scale (SBNS), the final outcomes appeared very grave. Except for 1 case in each group-1 grade III in the spina bifida aperta group and 1 grade II in the spina bifida occulta group-all patients over the age of 27 years were classed as having grade IV disease. There were 2 patients with spina bifida aperta in whom postoperative paraplegia appeared after delayed radical repair (at the ages of 3 years and 18 years) and 3 patients with spina bifida occulta in whom obvious neurological deterioration was observed as the natural history with ongoing paraparesis at the spinal level or late onset of sexual problems. The other group included 2 patients with spinal lipoma in whom late neurological deterioration was observed and who were obliged to undergo a second operation in spite of aggressive early procedures performed during infancy. Among the patients with spina bifida aperta, 2 had marked ventriculomegaly as a form of long-standing overt ventriculomegaly in the adult (LOVA). After the CSF shunt procedure both these patients had problems with delicate shunt dependence and requested fine shunt flow regulation. Two patients in this group also suffered from severe depression. This study involves a limited number of patients, but it may be useful for reference on various points: (1) future prospects for the management of pediatric cases of spina bifida as practiced in the majority of hospitals; (2) natural histories of untreated cases and surgical indications for preventive procedure in spinal lipoma in early infancy; and (3) internationally differing levels of management of spina bifida and the historical development of individual countries' approaches to the problems.

Adolescent↗
PubMed1996

Acrania: report of the first surviving case.

The first known surviving case of acrania is presented. The patient was the first child of a 29-year-old Japanese woman. Fetal ventriculomegaly was documented in the 35th gestational week. Prenatal sonography and magnetic resonance imaging suggested hydrocephalus with a wide encephalomeningocele. The baby was born at 38 weeks of gestational age by vaginal delivery. The patient had no calvarium, but did have a complete skull base with a partial defect in the occipital scalp and an underlying dural defect. Subsequently, the patient underwent repair of the scalp defect. At 3 months of age, after hydrocephalus developed, a subduro-peritoneal shunt was placed because of cosmetic and nursing problems. His developmental quotient was 10 at 3 years.

Adult↗
PubMed1995

Neuronal overmaturation in dysraphism: ontogenic expression of neuropeptides in the fetal brain and developmental anomalies in exencephaly.

Starting from knowledge obtained in our previous studies of experimental dysraphism in chick embryos, the entity of neuronal overgrowth observed in exencephaly was further investigated. The ontogenic expression of neuron-specific enolase (NSE), vasoactive intestinal polypeptide (VIP), and somatostatin was analyzed both in chick exencephaly of the natural product and in normal chick fetuses by carrying out immunohistochemical studies. In normal fetuses, immunostained elements positive for NSE first appeared in the spinal gray matter on postincubation day 16 and increased in intensity during the fetal period. By postnatal day 2, the cerebral peduncle, brain stem neurofibers, molecular layer of the cerebellum, corpus striatum, and piriform cortex became immunoreactive. No immunohistochemical reaction to VIP was observed during these stages. Somatostatin-positive elements were not identified during the fetal period, except in limited regions, such as the corpus striatum, which appeared to have weakly positive staining on day 21. The exencephalic fetuses, however, demonstrated extremely advanced neuronal maturation, with intense immunoreactivity already being manifest in various regions, including the corpus striatum, piriform cortex, spinal gray matter, and brain stem nuclei, on day 16 of the fetal period. Somatostatin-positive elements also appeared at this stage in chick exencephaly, but such immunoreactivity was localized, particularly in the overgrown foci. The present study showed that the neuronal maturation process in some neurons of exencephalic brain and spinal cord was definitely further advanced than that in normal controls. A possible clinical application of NSE and somatostatin measurement as markers for dysraphic states in the fetus is suggested.

Amniotic Fluid↗
PubMed1995

Experimental study of the embryogenesis of open spinal dysraphism.

This article discusses the experimental studies that have been performed to make clear the embryogenesis of myeloschisis or spina bifida. Some of these theories include: Simple nonclosure; overgrowth and nonclosure; so-called reopening; overgrowth and reopening; and primary mesodermal insufficiency. The authors also discuss recent investigations and give a view into the future.

Animals↗