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Biomedical subjects

H Furuya

Publications and source records attributed to H Furuya.

At least 109 records · Page 6Linked to original sources
PubMed1998

A case of shock subsequent to treatment of intracranial hypertension by mannitol injection combined with hyperventilation.

This report describes a sudden decrease in blood pressure after conservative treatment of acute intracranial hypertension. A 63-year-old woman with acute hydrocephalus after undergoing clipping of an aneurysm of the right supracerebellar artery developed increased intracranial pressure, necessitating surgical management. On the operating table, the patient developed Cushing's reflex. Mannitol injection combined with hyperventilation was begun immediately to reduce her intracranial pressure. Fifteen minutes later, a sudden and prolonged suppression of circulation was observed (blood pressure 65/35-85/40 mmHg, heart rate 90-100 beats/min). Postoperatively, computed tomography of the head showed compression of the brain stem. We believe that this patient's blood pressure decrease was related to a sudden reduction of intracranial pressure and that mannitol injection was principally responsible for this occurrence.

Diuretics, Osmotic↗
PubMed1998

The effect of sevoflurane on myogenic motor-evoked potentials induced by single and paired transcranial electrical stimulation of the motor cortex during nitrous oxide/ketamine/fentanyl anesthesia.

To overcome anesthetic-induced depression of myogenic motor-evoked potentials (MEPs), several techniques of stimulation using paired pulses or trains of pulses are used. This study investigated the effect of sevoflurane on myogenic MEPs induced by single and paired transcranial electrical stimulation of the motor cortex. Nine patients undergoing elective spinal surgery were anesthetized with fentanyl-N2O-ketamine. Partial neuromuscular blockade (single-twitch height 15% of baseline) was maintained with vecuronium. Single and paired (interstimulus interval 2 milliseconds) electrical stimuli were delivered to the scalp, and compound muscle action potentials were recorded from the left and right tibialis anterior muscles. In all patients, baseline MEPs were recorded from both the left and right anterior tibialis muscles (in a total of 18 legs). During the administration of 0.25 MAC and 0.5 MAC sevoflurane, MEPs induced by stimulation with a single pulse could be recorded in 12 of 18 and 4 of 18 legs, respectively, and MEP amplitude was significantly reduced to 48% and 4% of the control value, respectively. During the administration of 0.75 MAC sevoflurane, MEPs following single-pulse stimulation could not be recorded in any legs. The success rate of MEP recording during the administration of sevoflurane was greater after paired stimulation than after single stimulation, and percentage MEP amplitude (percentage of the control value after single stimulation but before sevoflurane) after paired stimulation was significantly higher than after single stimulation before and during the administration of 0.25 MAC and 0.5 MAC sevoflurane. The success rate of MEP recording and MEP amplitude after paired stimulation decreased in a dose-dependent manner during the administration of sevoflurane. These results suggest that although facilitation by the second stimulus was considerable, paired stimuli are still not sufficient to overcome the depressant effects of sevoflurane in clinically used concentrations.

Action Potentials↗
PubMed1998

[Flow cytometric analysis of the effects of 50 Hz magnetic fields on mouse spermatogenesis].

The cellular effects of an extremely-low-frequency (ELF) magnetic field on mouse spermatogenesis were assessed by DNA flow cytometry and serum testosterone. Seven week old male ICR mice were exposed to a 50 Hz magnetic field the strength of which was 1.0 m Tesla. Seven mice per treatment group were exposed for 13, 26, 39 or 52 days. For each experimental point, an equal number of mice per sham-treated group were used as a control and were exposed only to the background field below 1 mu Tesla in the same room as the treatment group. In the control mice, the testis cellular DNA content distribution by flow cytometory was characterized by four quantifiable populations; round spermatids (1C), spermatogonia and other diploid cells (2C), spermatogonial cells synthesizing DNA (S-phase) and primary spermatocytes (4C). In animals exposed for 26 days the number of cells in the 4C and the 4C:2C ratio was significantly lower, and the 1C:4C ratio (meiotic transformation) was significantly higher than the corresponding control groups. In animals exposed for 52 days the cell population in 1C and the 1C:2C ratio (total germ-cell transformation) was significantly higher, and the cell population in 2C was significantly lower than the corresponding control groups. The concentration of serum testosterone in animals exposed for 13 days was significantly higher than in the corresponding control group. These changes suggest that long-term exposure to an ELF magnetic field had a possible effect on the proliferation and differentiation of spermatogonia.

Animals↗
PubMed1998

[Analysis of postoperative shivering following the deliberate mild hypothermia during neurosurgery].

We induced deliberate mild hypothermia in 96 patients who underwent intracranial operations using a water blanket and a convective device blanket. The lowest temperature measured at the tympanic membrane during mild hypothermia was adjusted to 34.5 degrees C. The patients were divided into two groups in respect to the occurrence of postoperative shivering, and the relationship between the perioperative parameters and the occurrence of postoperative shivering was evaluated. Shivering was observed postoperatively in 29 to 96 patients (30.2%). In the group with shivering (SV), age was significantly lower and body weight and body surface area were significantly larger than the group without shivering (NSV). Urinary output was significantly larger in SV than in NSV. Tympanic membrane, nasopharyngeal, and rectal temperatures at the end of surgery and nasopharyngeal, rectal, and peripheral temperatures just after the extubation were significantly lower in SV than in NSV. These results suggest that sufficient rewarming of both the core and peripheral temperatures is important to prevent the postoperative shivering following the mild hypothermic therapy in neurosurgical patients, especially in young patients.

Adult↗
PubMed1997

Constitutive tyrosine phosphorylation of the vav proto-oncogene product in MRL/Mp-lpr/lpr mice.

MRL/Mp-lpr/lpr (lpr) mice develop autoantibodies, vasculitis, and glomerulonephritis, which are similar to human systemic lupus erythematosus, and acquire a generalized, nonmalignant, lymphoproliferative disorder. CD4- CD8- CD3+ TCR alphabeta+ (double-negative, DN) T cells accumulate in spleen and lymph nodes, and become a major T cell population in vivo. These DN T cells, however, are refractory to various stimuli, including CD3, IL-2, CD28, PMA, and PHA. Recently, the lpr gene mutation has been identified as a mutant gene for Fas, resulting in expression defects of Fas Ag. It is still unclear, however, what kinds of mechanisms cause the dysfunction of lpr DN T cells. To elucidate the pathogenic mechanisms in abnormal DN T cells, biochemical analyses were conducted for the expression and tyrosine phosphorylation of the vav proto-oncogene product (Vav) in DN T cells from lpr mice. We demonstrated that Vav, a 95-kDa cytoplasmic protein, from lpr mice was constitutively tyrosine phosphorylated several times higher than in control +/+ mice, while expression of Vav protein in lpr and +/+ mice was equal. Additionally, in contrast with +/+ T cells, tyrosine phosphorylation of Vav, which normally increases within a minute of stimulation via TCR, did not increase in lpr DN T cells following PHA or Ab activation. Taken together with the suggested roles of Vav in multiple receptor-mediated signal transductions, our findings suggest that the functional abnormalities of lpr DN T cells may be related to Vav abnormal tyrosine phosphorylation, which could lead to impaired signaling between surface receptors and G proteins in this cell population.

Animals↗
PubMed1997

Effects of electrochemotherapy on CaSki cells derived from a cervical squamous cell carcinoma.

Electrochemotherapy is a new approach to the treatment of tumors that takes advantage of the permeabilization of the cell membranes by electric pulses to facilitate the intracellular delivery of chemotherapeutic drugs into cells. Using the female genital squamous cell carcinoma cell line, CaSki, the antitumor effectiveness of electrochemotherapy was tested. In vitro studies showed that the cytotoxicity of some anticancer drugs, especially bleomycin, can be greatly enhanced by exposing cells to noncytotoxic electric pulses. This enhancement was significantly greater when the electric treatment was given after exposure to the drug than when applied preexposure. Treatment of nude mice bearing subcutaneous transplanted tumors with noneffective intraperitoneal doses of bleomycin followed by local delivery of electric pulses similar to those performed in vitro resulted in tumor reduction and complete disappearance after 12 days this electrochemotherapy. Histological changes in tumor tissue such as necrosis and degeneration were extensive even 6 hr after the electrochemotherapy. Thus the antitumor effects of bleomycin in mice can be considerably potentiated by local electric pulses, suggesting that electrochemotherapy with bleomycin may have promise for treatment of vulvar or ectocervical squamous cell carcinomas with early invasion.

Animals↗
PubMed1997

Adult onset globoid cell leukodystrophy (Krabbe disease): analysis of galactosylceramidase cDNA from four Japanese patients.

We examined galactosylceramidase (GALC) cDNA in four Japanese patients with adult onset globoid cell leukodystrophy (Krabbe disease; AO-GLD) by polymerase chain reaction/single-strand conformation polymorphism (PCR-SSCP) analysis, subsequent sequence determination, and restriction enzyme digestion of PCR products, initial symptoms were the onset of slowly progressive spastic paraplegia from the middle of the second decade, and all patients had diminished GALC activity in their leukocytes. We identified three missense mutations (I66M, G270D, L618S) and one exon-6 skipping (535-573del). Two of the patients had only the I66M mutant mRNA, and one only the G27OD mutant mRNA. The fourth patient carried a compound heterozygous mutation of 535-573del and L618S. To determine the enzymatic activities produced by these mutations, we constructed mutated GALC cDNAs and expressed them in COS-1 cells. Three mutations, viz., G270D, L618S, and exon-6 skipping (535-573del), produced diminished GALC activity as expected. The I66M mutation in the wild-type GALC cDNA(I289) had normal activity, but when this mutation and the V289 polymorphism were introduced into the same allele, it had decreased activity. Thus, the combination of a unique mutation and polymorphism causes conformational change in the GALC enzyme, resulting in low enzymatic activity. AO-GLD mutations, including those found here, are located in the N-terminus (I66M, G270D, 535-573del) or C-terminus (L618S) of the GALC enzyme, whereas the reported mutations in the infantile form (IF-GLD) are in the central domain. This difference in mutation sites may affect the clinical features of GLD.

Adult↗
PubMed1997

Risk factors for neurologic deterioration after revascularization surgery in patients with moyamoya disease.

UNLABELLED: To investigate the risk factors for postoperative neurological deterioration in patients with moyamoya disease, we retrospectively reviewed the perioperative course of 368 cases of revascularization surgery in 216 patients with this disease. Risk factors anecdotally associated with postoperative ischemic events were analyzed by comparing groups with or without a history of such events on the operative day. Ischemic events were noted in 14 cases (3.8%), 4 of which were defined as strokes and the others as transient ischemic attack (TIA). Postoperative neurological deterioration more often developed in patients who suffered from frequent TIAs, had precipitating factors for TIA, and underwent indirect nonanastomotic revascularization. The authors conclude that the incidence of postoperative ischemic events were related more to the severity of moyamoya disease and the type of surgical procedure than to other factors, including anesthetic management. IMPLICATIONS: Although preventing stroke is the major concern for patients with moyamoya disease, risk factors for perioperative cerebral ischemia have not been clarified. We retrospectively analyzed the perioperative course in 368 cases with this disease and found that the severity of the disease and type of surgical procedure were major determinants of postoperative cerebral ischemia.

Adolescent↗
PubMed1997

Adult-onset Krabbe disease with homozygous T1853C mutation in the galactocerebrosidase gene. Unusual MRI findings of corticospinal tract demyelination.

A 51-year-old woman developed a slowly progressive spastic paraparesis and diminished vibration sense beginning at age 38. Intellectual capacity was normal. Krabbe disease was confirmed by markedly reduced leukocyte galactocerebrosidase (GALC) activity, typical inclusions in Schwann cell cytoplasm, and an identification of the homozygous point mutation T1835C (Leu618Ser) in the GALC gene. T2-weighted MRI of the brain showed symmetric high-signal-intensity lesions in the bilateral frontoparietal white matter, the centrum semiovale, and the posterior limb of the internal capsule with sparing of the periventricular white matter. This case is unusual because of the late onset, protracted clinical course, and MRI findings of demyelination confined to the corticospinal tracts.

Age of Onset↗
PubMed1997

Clinical courses and thyroid conditions in three infants born to a mother with thyroid stimulating-blocking antibodies.

The clinical courses including thyroid conditions of three infants born to a mother with primary hypothyroidism due to Hashimoto's thyroiditis were studied. The mother was positive for both TSH-binding inhibitor immunoglobulins (TBII) and thyroid stimulating-blocking antibodies (TSBAb) in her serum. The first infant died because of septic shock due to fistula formation between the large intestine and the bladder. Serum thyroid hormone levels during the first pregnancy were extremely low because of incomplete replacement therapy with levothyroxine. The second infant had almost normal thyroid function, so that the replacement therapy was not necessary. The third infant had transient and overt primary hypothyroidism. The replacement therapy was carried out for six months after birth. TSBAb activities in this mother were high in the third pregnancy. In general, these activities gradually increases with the clinical course in TSBAb-positive Hashimoto's patients. From these findings, it was suspected that the thyroid conditions in the second and the third infants reflected the natural course of TSBAb activities in this mother.

Adult↗
PubMed1997

Incidence of hyperprolactinemia in patients with Hashimoto's thyroiditis.

The causes of hyperprolactinemia, the correlation between serum levels of PRL and thyroid function and magnetic resonance imaging (MRI) of the pituitary were studied in patients with chronic thyroiditis. Seventy-four female patients and 15 normal control women participated in this clinical survey. Fourteen of 74 patients with various thyroid conditions had increased serum PRL. The incidence of hyperprolactinemia in the overt primary hypothyroid group was 42.4% and was significantly higher than in any other group with normal serum thyroxine. There was a close association between the increment in serum PRL and of free triiodothyronine above the basal level after TRH administration. There were 14 patients with hyperprolactinemia in three of which serum PRL was over 60 micrograms/L. PRL producing tumor, severe primary hypothyroidism and liver cirrhosis were detected in these three patients, respectively. These results indicate that the pathogenesis of increased serum PRL was not uniform in patients with Hashimoto's thyroiditis, although there was a correlation between hyperprolactinemia and impaired thyroid function. It is proposed, therefore, to measure and follow serum levels of PRL and MRI of the pituitary in patients with chronic thyroiditis, especially with impaired thyroid function.

Adult↗
PubMed1997

Acute hydrocephalus in posterior fossa injury.

This is the first known report of the use of computerized tomography (CT) scanning to examine acute hydrocephalus in posterior fossa injury. Of the 1802 patients with acute head trauma treated at Funabashi Municipal Medical Center, 53 (2.9%) had suffered injury to the posterior fossa. Of these, 12 patients (22.6%) had associated acute hydrocephalus: nine patients with acute epidural hematoma (AEH) and three with intracerebellar hematoma and contusion (IH/C). There was a significant relationship between cases of AEH with hydrocephalus and supratentorial extension, hematoma thickness of 15 mm or more, and abnormal mesencephalic cisterns. In cases of IH/C, bilateral lesions and no visible fourth ventricle were significant causes of hydrocephalus. According to these results, possible mechanisms of acute hydrocephalus in posterior fossa injury may be as follow: in cases of AEH, hematoma that extends to the supratentorial area compresses the aqueduct posteriorly and causes hydrocephalus; in cases of IH/C, hematoma and contusional lesions may directly occlude the fourth ventricle and cause acute hydrocephalus. Seven patients suffering from AEH with acute hydrocephalus underwent evacuation of their hematoma without external ventricular drainage. In these cases, CT scanning showed that the hydrocephalus improved immediately after evacuation of the hematoma. Two patients suffering from IH/C with hydrocephalus underwent a procedure for evacuation of the hematoma and external ventricular drainage. The authors do not believe that ventricular drainage is necessary in treating posterior fossa AEH. However, both evacuation of the hematoma and ventricular drainage are necessary in cases of IH/C with hydrocephalus to provide the patient with every chance for survival. There was no significant difference in mortality rates when cases of AEH with acute hydrocephalus (0%) were compared with cases of AEH without hydrocephalus (7.7%). The observed mortality rates in cases of IH/C with hydrocephalus and those without hydrocephalus were 100% and 15.4%, respectively; this is statistically significant.

Acute Disease↗
PubMed1997

[A case of severe involvement of the motor neuron system accompanied with cerebellar ataxia].

Here we report a sporadic case of severe involvement of the motor neuron system accompanied with cerebellar ataxia. A 55-year-old Japanese woman was admitted to our hospital because of unstable gait and clumsiness of hands. Since she had prominent ataxia, she was initially diagnosed as late onset cortical cerebellar atrophy (LCCA). However, mild muscular weakness and atrophy were pointed out. Weakness in extremities progressed slowly and she became unable to walk in two years. On the second admission, in addition to cerebellar ataxia, she had moderate to severe muscular weakness and atrophy with fasciculation in extremities. Although she had no sensory impairment, micturitional disturbance nor orthostatic hypotension, she had impaired skin sweating response. MRI imaging revealed moderate cerebellar and brain stem atrophy. Neurophysiological examination revealed upper and lower motor neuron damage. Beta-D-N acetylglucosaminidase activity was normal and SCA1, DRPLA and Machado-Joseph disease were excluded by DNA studies. Combination of motor neuron disease and cerebellar degeneration has been very rare. Only two cases similar to our case were reported before. Our patient had anti GM1-ganglioside antibody in her serum, suggesting that motor neuron disease and cerebellar degeneration may occur with the same pathophysiological mechanism.

Cerebellar Ataxia↗
PubMed1997

[Effects of amrinone on oxygen demand-supply relationship after cardiopulmonary bypass in patient undergoing coronary bypass surgery].

We evaluated the effects of amrinone on oxygen demand-supply relationship after cardiopulmonary bypass (CPB) in patient undergoing coronary bypass surgery comparing with the patients not receiving amrinone. In amrinone treated patients bolus dose of amrinone 1.5 mg.kg-1 was administrated into the reservoir of CPB and followed by continuous infusion at a rate of 5 micrograms.kg-1.min-1. Hemodynamics and blood gas (arterial and mixed venous) measurements were carried out immediately after CPB, 1 hour after CPB and after the chest closure. After the chest closure, cardiac index and oxygen supply in amrinone treated group were significantly higher and systemic vascular resistance was significantly lower than in non-treated group. Left ventricular stroke work index, rate pressure product and oxygen consumption showed no significant difference between the two groups. These data indicate that the amrinone treated patients preserved better oxygen demand-supply relationship after CPB compared with the non-treated patients undergoing coronary bypass surgery.

Amrinone↗
PubMed1997

[A case report of alternating abducens hemiplegia with special reference to the supranuclear pathway to the facial nucleus].

A case of alternating abducens hemiplegia was reported. A 16-year-old girl developed alternating hemiplegia characterized by the left abducens nerve palsy and right hemiparesis. In addition, she had right supranuclear facial nerve palsy. A brain MRI showed left mid to lower pontine lesion and vertebral angiography revealed medullary venous malformation in the left pons. SEP with right posterior tibial nerve stimulation showed a delayed central conduction time, suggesting that the lesion involved left medial lemniscus. We previously reported a 39-year-old man who developed pure alternating abducens hemiplegia. He did not show supranuclear facial nerve palsy or SEP abnormality. These findings support the idea that the supranuclear facial nerve fiber leaves the pyramidal tract at the upper to middle pons and descends in the area of the pontine tegmentum around the medial lemniscus.

Abducens Nerve↗
PubMed1997

[Regional cerebral hypoperfusion reduces the effect of rectal midazolam in children with Moyamoya disease].

To investigate the effect of regional cerebral blood flow on the effect of midazolam, we evaluated 99mTc-hexamethylpropylene-amine-oxime-single photon emission computed tomography (SPECT) in 37 cases of childhood moyamoya disease. They were divided into two groups according to the findings of SPECT; one group showed hypoperfusion in the bifrontal regions (n = 20), and the other did not (n = 17). Both groups received 1 mg.kg-1 of midazolam transrectally 30 min before the anesthesia induction and level of sedation was measured with six point scales. Significantly lower level of sedation score was recognized in the group that showed hypoperfusion in bifrontal regions (P < 0.05). Our finding may suggest that regional cerebral hypoperfusion may modify the sedative effect of midazolam in children with moyamoya disease.

Administration, Rectal↗