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Biomedical subjects

M Kawaguchi

Publications and source records attributed to M Kawaguchi.

At least 145 records · Page 8Linked to original sources
PubMed1998

Postoperative neurological deterioration following the revascularization surgery in children with moyamoya disease.

We describe four children with moyamoya disease who developed neurologic deterioration following revascularization surgery. In all cases, anesthesia was smoothly induced and the intraoperative course was uneventful. Emergence from anesthesia was prompt and no new neurological deficit was observed. However, the children suffered strokes on 2, 4, 5, and 10 days, postoperatively, respectively. Dehydration and crying were thought to be closely associated with the stroke in each case. This report suggests that attention should be paid during entire the perioperative period to avoid stroke in patients with moyamoya disease.

Brain↗
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

A case of infantile digital fibromatosis with spontaneous regression.

We reported a fourteen-month-old boy with infantile digital fibromatosis. At the age of seven months, a nodule appeared on the back of the left third toe, and developed into a slight red tumor divided into five hemispherical nodules. Histopathologically, spindle-shaped tumor cells with an eosinophilic inclusion body in the cytoplasm were seen in the dermis. Electron microscopy showed a dense body in the cytoplasm of the tumor cells. One year and two months after the first visit, the tumor regressed without any aggressive treatment. Japanese cases of infantile digital fibromatosis were reviewed. The literature review and our case suggest that the tumor should be observed without any aggressive treatment unless it causes mobile dysfunction of the affected finger or toe.

Diagnosis, Differential↗
PubMed1998

Platelet epidermal growth factor in thyroid disorders.

We evaluated the concentration of epidermal growth factor (EGF) in platelets, serum and plasma obtained from 47 patients with Graves' disease, 7 with hypothyroidism and 20 healthy subjects. The platelets of the subjects were collected from platelet rich plasma and lysed by freezing and thawing. Subsequently the platelet debris was treated with Triton X-100. The EGF concentration was determined by homologous radioimmunoassay. The concentration of EGF in the platelets in 14 patients with untreated Graves' disease was significantly higher than that in the healthy controls. After treating these 14 patients with antithyroid agents, the EGF concentration in the platelets decreased to the level of the healthy controls. The EGF concentration in the platelets in the 7 untreated hypothyroid patients decreased after replacement therapy with thyroxine. The mean volume of the platelets in the 14 patients with untreated Graves' disease was significantly larger than in the control and decreased after treatment with antithyroid agents. The serum and plasma levels of EGF in the 7 untreated hypothyroid increased after replacement therapy. In conclusion, thyroid function affected the concentration of EGF in the platelets of patients with thyroid disorders.

Adult↗
PubMed1998

Relationship between the electrical resistivity of enamel and the relative humidity.

The present study was carried out to investigate the relationship between the relative humidity and the electrical resistivity of enamel in vitro. The electrical resistivity of enamel samples was measured in a thermo-hygrostat where the relative humidity varied between 60% and 90%, with the measurements carried out first in a descending direction and then in an ascending direction. When the electrical resistivity was measured from a low to high relative humidity in an ascending direction, a higher value of electrical resistivity was always obtained in comparison to that when measured in the reverse descending direction. The difference between the mean electrical resistivity in an ascending and a descending direction increased in proportion to the relative humidity. These findings suggest that the diffusion of electrolytes and water in enamel is sensitive to changes in the relative humidity.

Adult↗
PubMed1998

Postlaminectomy cervical spinal cord compression demonstrated by dynamic magnetic resonance imaging. Case report.

This 32-year-old man had undergone C3-7 laminectomy for posttraumatic cervical myelopathy associated with spinal canal stenosis. He developed recurrent myelopathy 5 years after the initial operation. Dynamic magnetic resonance (MR) imaging of the cervical spine demonstrated spinal cord compression with diffuse canal stenosis while the neck was in the extended position, whereas no significant stenosis was visualized in the neutral position. Sagittal and axial MR images of the affected levels demonstrated striking changes in the cervical spinal cord configuration. Because of an associated hard osteophyte formation and protruded disc, as well as a hypertrophied posterior longitudinal ligament, an anterior decompression and fusion with plate fixation were performed from C-4 to C-7. The postoperative course was uneventful, with subsequent neurological improvement. It is concluded that dynamic MR imaging aids the search for the cause of recurrent postlaminectomy cervical myelopathy after initial improvement following decompressive surgery.

Adult↗
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

A comparison of ultrastructural changes on endomyocardial biopsy specimens obtained from patients with diabetes mellitus with and without hypertension.

The pathogenesis of diabetic cardiomyopathy is unknown. The synergistic, or enhanced, effect of hypertension on pathological changes in the heart of diabetic patients has been highly suspected. The purpose of this study was to evaluate the myocardial changes related to diabetes mellitus with and without hypertension, using biopsy specimens. We examined the ultrastructural changes in biopsy specimens of the endomyocardium obtained from 25 patients. They were divided into four groups: controls without hypertension or diabetes mellitus (n = 6), and patient with hypertension (n = 3), diabetes mellitus (n = 8), and diabetes with hypertension (n = 8). The diabetic patients showed nearly normal or mildly depressed systolic left ventricular function. Ultrastructural pictures were analyzed for thickening of the capillary basement membrane, presence of toluidine blue-positive materials (i.e., materials showing metachromasia) in the myocytes, size of myocytes, and interstitial fibrosis. The thickening of the capillary basement membrane, the accumulation of toluidine blue-positive materials, and interstitial fibrosis were all significantly greater in the patients with diabetes mellitus compared to the control subjects. The myocytes tended to be small (cell atrophy) in the diabetes group. Although these pathological changes in the heart were characteristic of diabetic patients, irrespective of the presence or absence of hypertension, the presence of hypertension increased the pathological changes of myocardial cells as well as abnormality in the capillary vessels in patients with diabetes mellitus. Alterations in the myocardial cells and capillaries, caused by diabetes mellitus, may lead to myocardial cell injury and interstitial fibrosis and, ultimately, to ventricular systolic and diastolic dysfunction, especially when the diabetes is accompanied by hypertension.

Adult↗
PubMed1997

Effects of dehydroepiandrosterone on proliferation of human aortic smooth muscle cells.

Dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) have been shown to be associated with the progression of coronary atherosclerosis in clinical and in vivo studies. However, the mechanisms responsible for the association have not been determined. In the present study, we found that DHEA influences the in vitro growth of vascular smooth muscle cells obtained from the human aorta (hASMC). The concentrations of DHEA ranging from 10(-8) M to 10(-6) M significantly stimulated the mitogenesis of hASMC in serum-free culture. On the other hand, 4 hrs of pretreatment with DHEA attenuated the fetal calf serum induced proliferative effect in a dose-dependent manner. However, the in vitro effects of DHEA on the mitogenesis observed in hASMC were not seen in rat-derived aortic smooth muscle cell lines (A10 cells). With respect to DHEAS, the hormone, at concentrations up to 10(-5) M did not affect the growth of either hASMC or A10 cells in vitro. The growth response of hASMC to DHEA in vitro was markedly affected by the culture conditions. The differential proliferative effects of DHEA on smooth muscle cells between rat and human are of interest. We conclude that the effects of DHEA on mitogenesis of hASMC may, at least in part, explain the association between DHEA and atherosclerosis.

Animals↗
PubMed1997

Vascularized fibula graft for spinal fusion in severe cervical kyphosis due to neurofibromatosis.

A successful anterior spinal fusion using vascularized fibula graft in the case of a 17-year-old male with severe cervical kyphosis due to neurofibromatosis is reported. Anterior spinal fusion at C2-7 using the fibula graft was performed with spinous process wiring. The kyphosis was corrected from 85 to 38 degrees. Bony fusion was obtained in 5 months without loss of correction.

Adolescent↗
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

Effect of aging on B-cell function and replication in rat pancreas after 90% pancreatectomy.

We studied the effect of aging on B-cell function and replication in depancreatized rats. Male Wistar rats, at the ages of 1, 5, and 15 months, underwent 90% pancreatectomy (Px) or a sham operation, and islet function and regeneration were examined 3 weeks later. Plasma glucose levels in 1-month-old rats reached a peak 2 weeks after Px and then declined, while those in 5- and 15-month-old rats reached significant levels as early as the day after Px or 2 days after surgery and continued to increase over the following 3 weeks. Consequently, in contrast to young Px rats, weight loss due to severe diabetes was observed in 5- and 15-month-old Px rats. Plasma glucose responses to intravenous glucose loading (0.5 g/kg body weight) were much greater in older Px rats than in younger rats. There was a marginal insulin response to glucose in 1-month-old Px rats, whereas no insulin response to glucose was observed in older Px animals. The insulin content of the residual pancreas was increased threefold in 1-month-old Px rats, but there was no increase in 5- and 15-month-old Px rats. These data demonstrate that the effect of reducing islet mass is much greater in aged rats than in young rats and that the replicatory capacity of B cells tends to diminish after adulthood has been reached.

Aging↗
PubMed1997

Delayed release of prostaglandins from arachidonic acid and kinetic changes in prostaglandin H synthase activity on the induction of prostaglandin H synthase-2 after lipopolysaccharide-treatment of RAW264.7 macrophage-like cells.

In a mouse macrophage-like cell line, RAW264.7, arachidonic acid was cleaved within 30 min of lipopolysaccharide (LPS)-treatment. However, prostaglandin (PG) synthesis did not accompany this cleavage, being delayed by 4 h, although significant PGH synthase (PGHS) activity was detected in the lysate of LPS-nontreated cells. The K(m) value of this basal PGHS activity toward arachidonic acid was more than one hundred-fold higher than that for the lysate of cells treated with LPS for 4 h. Changes in the sensitivity of the PGHS activity to nonsteroidal antinflammatory drugs after LPS-treatment also suggested induction of PGHS with different properties from that in the case of basal PGHS. The concomitant increase in PGH synthase (PGHS) activity with the induction of PGHS-2 protein after LPS-treatment suggested a contribution by PGHS-2 to the delayed synthesis of PGs in LPS-treated macrophage cells. As for PGHS in the control cells without LPS-treatment, a different K(m) value from that of PGHS-1 and the lack of cross-reactivity to anti-PGHS-1 antibodies suggested that this basal PGHS was different from the typical PGHS-1. The lower affinity of this enzyme for arachidonic acid might be the reason for the failure to release PGs by the cells without LPS-treatment.

Animals↗