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Biomedical subjects

R Kagawa

Publications and source records attributed to R Kagawa.

At least 19 recordsLinked to original sources
PubMed2004

Role of women in medicine: a look at the history, the present condition and the future status of women in the surgical field, especially neurosurgery.

We have analyzed the historical background of women's progress in medicine in Japan and the role of female neurosurgeons as models for the next generation. Female neurosurgeons were asked to complete a questionnaire regarding their professional life in detail and the problems they are facing while managing their personal life after getting married and having a child. Some feel that there remain some constraints at work for being a female, due to their male colleagues who are not so understanding in nature. The younger generation is not so keen on joining the neurosurgical branch as their life career due to hard work and complete dedication demanded by neurosurgery. It is not easy for all to manage a neurosurgical career along together with a married life and children. Hence it is now time for those successful female neurosurgeons to become role models. Government can play an important role in these social reforms by coming up with programs to give social security to females and initiate programs for child care for married females pursuing such a demanding profession. Certain measures to encourage females to take up surgery are providing more time by arranging care for babies and families, flexibility in working hours, in addition to having a considerate husband and a considerate chief of department and senior staff. Departmental policies need to be completely impartial and should promote everyone based on their skills and knowledge. Women neurosurgeons need to get together and discuss all these issues so that the younger generation will not hesitate to take up this profession and become stalwarts of neurosurgery like their male counterparts.

Adult↗
PubMed2001

B-mode ultrasonographic investigations of morphological changes in endarterectomized carotid artery.

BACKGROUND: The aim of this study was to assess morphological changes in the endarterectomized carotid region using B-mode ultrasonography (USG). METHODS: USG examinations were performed on 54 Japanese patients who underwent carotid endarterectomy (CEA). The endarterectomized regions were periodically investigated and the intima-media thickness (IMT) was measured. RESULTS: Postoperative USGs revealed an evident step formation (type I: 20.4%), a gentle slope (type II: 42.6%), or complete smoothness (type III: 37.0%) at the junction of the endarterectomized carotid region and the common carotid artery (CCA). The IMT of the CCA progressively increased from type I to type III. Patients were followed up for an average of 2.7 years. The new intima-media complex (IMC) was confirmed in all cases after 9 months; it was visualized as an isoechoic layer (7%) or a mixture of iso- and hypoechoic layers (93%). Changes in the IMT during the follow-up period were classified into three groups: no change (group I: 23.1%), decrease (group II: 15.4%), and increase (group III: 61.5%). CONCLUSIONS: USG is useful to clarify the complicated healing processes of the endarterectomized carotid artery.

Adult↗
PubMed1999

Traumatic dissection of the common carotid artery after blunt injury to the neck.

BACKGROUND: Occlusive lesions of the common carotid artery (CCA) resulting from blunt injury are extremely rare, and their clinicopathologic and therapeutic features have not yet been clarified. OBJECTIVES AND RESULTS: Five patients with occlusive lesions of the CCA developed neurologic deficits at 1.5 hours to 10 years after blunt neck injury. Lesions included two complete occlusions, one severe stenosis, and two segmental intimal dissections of the CCA. In the two patients with CCA occlusion, bypass surgery was performed using a Dacron graft between the ipsilateral subclavian artery and the carotid bifurcation. In the remaining three patients, the involved segments were replaced with a Dacron graft. Surgical specimens from the early posttraumatic period revealed intimal tears with mural thrombosis and/or subintimal hematomas and those from the later period showed myointimal hyperplasia or fibrotic organization. CONCLUSION: Traumatic occlusive lesions of the CCA tend to evolve from intimal dissections to severe stenoses or occlusion, compromising cerebral circulation. The involved CCA can be diagnosed early by B-mode Doppler sonography and successfully reconstructed using a Dacron graft.

Adult↗
PubMed1999

Cylindrical or T-shaped silicone rubber stents for microanastomosis--technical note.

The ostium of the recipient artery and the orifice of the donor artery must be clearly visualized for the establishment of microvascular anastomosis. Specially designed colored flexible cylindrical or T-shaped silicone rubber stents were made in various sizes (400 or 500 microns diameter and 5 mm length) and applied to bypass surgery in patients with occlusive cerebrovascular disease such as moyamoya disease and internal carotid artery occlusion. The colored flexible stents facilitated confirmation of the ostium of the artery even in patients with moyamoya disease and allowed precise microvascular anastomosis without problems caused by the stent.

Anastomosis, Surgical↗
PubMed1999

Neuroimaging findings of the development and resolution of solitary brainstem abscess: characteristics of neuroimagings in the early stage of brainstem abscess and importance of surgical management for brainstem abscess--case report.

A 64-year-old female presented with a solitary brainstem abscess. Magnetic resonance imaging and computed tomography demonstrated the development and resolution of the brainstem abscess with an unusual and fluctuating clinical course over several months. Serial neuroimaging examinations are required to detect a brainstem abscess in the early stage to establish the optimum treatment.

Brain Abscess↗
PubMed1998

Magnetic resonance angiography visualization of four vessel (bilateral carotid and vertebral artery) occlusion--two case reports.

A 44-year-old female with transient vertigo and a 51-year-old female with headache and numbness of the hand presented with four vessel occlusion of the cerebral arteries (bilateral internal carotid arteries and bilateral vertebral arteries). This is an extremely rare entity, and the clinicoradiological features are not well documented. Magnetic resonance (MR) angiography visualized the cerebral arterial occlusion. Conventional angiography confirmed the diagnosis and demonstrated extensive collateral vessels. MR angiography is a useful method for screening patients with minimal or no symptoms for abnormalities in the cerebral circulation.

Adult↗
PubMed1996

Validity of B-mode ultrasonographic findings in patients undergoing carotid endarterectomy in comparison with angiographic and clinicopathologic features.

BACKGROUND AND PURPOSE: Determining factors for performing carotid endarterectomy (CEA) are the severity of carotid stenosis and the presence of plaque ulcerations. Precise detection of these factors is important. The aim of this study was to assess the applicability of using B-mode ultrasonography for diagnosing carotid lesions in patients undergoing CEA. METHODS: B-mode examinations were performed on 64 Japanese patients (68 arteries) who subsequently underwent CEA. In each case, the appearance of plaque on B-mode was classified into one of two types: heterogeneous or homogeneous; plaque echogenicity was expressed as hypoechoic, isoechoic, or hyperechoic. Surface characteristics such as ulceration also were examined, and the degree of carotid artery stenosis was calculated. The B-mode findings were compared with angiographic and pathological features. RESULTS: B-mode accurately visualized macroscopic ulceration and surface irregularity in 93.8% of the lesions examined, which was superior to angiography. Fifty-four lesions (79.4%) were of the heterogeneous type and 14 lesions (20.6%) were of the homogeneous type on B-mode. Microscopically, 57.4% of the heterogeneous-type lesions demonstrated fibrous change. The frequency of calcification was higher in the heterogeneous lesions than in the homogeneous lesions. CONCLUSION: B-mode ultrasonography findings can provide information about macroscopic and microscopic characteristics of carotid lesions.

Adult↗
PubMed1995

Effect of gabexate mesilate on thrombin and plasmin generation after hepatic resection in cirrhotic patients.

The effect of the gabexate mesilate (Gab) on thrombin and plasmin generation following liver resection in cirrhotic patients was studied. Six cirrhotic patients received an infusion of Gab after liver resection (Gab group), and another 6 patients did not receive such treatment (Con group). The parameters measured were thrombin-antithrombin complex (TAT), plasmin-antiplasmin complex (PAP) and D-dimer. The real increases of D-dimer and PAP were significantly higher in Con group after surgery while no significant difference was observed in the increase of TAT. These results show that Gab suppresses plasmin generation and following D-dimer production more effectively than thrombin generation after hepatic resection.

Aged↗
PubMed1995

Decreased energy charge of peripheral blood lymphocytes in septic patients after hepatic resection.

We measured lymphocyte energy charge (LEC) in septic patients after hepatectomy to clarify the energy metabolism of lymphocytes in relation to arterial ketone body ratio (AKBR) reflecting the hepatic mitochondrial redox potential. Sixteen patients with AKBR above 0.7 (state A) tolerated their operations well without postoperative infectious episodes and their LEC (0.895 +/- 0.005, mean +/- SEM) was significantly (p < 0.001) higher than that (0.841 +/- 0.010) of 9 patients with AKBR from 0.7 to 0.4 (state B). Four of the 9 state B patients had multiple organ failure (MOF) with sepsis as a trigger. AKBR in 7 of 9 state B patients decreased and remained below 0.4 (state C). These state C patients showed significantly reduced LEC (0.781 +/- 0.024; p < 0.001, p < 0.05, compared with that in states A and B, respectively) and finally died of MOF with septic state. These results suggest that the severe and prolonged impairment of energy metabolism in the liver may be accompanied with the metabolic derangement of lymphocytes.

Aged↗
PubMed1994

Diffusion anisotropy of cerebral ischaemia.

Focal cerebral ischemia was produced by occlusion of the middle cerebral artery with a silicone cylinder in Wistar rats. Diffusion-weighted echo-planar images (DW-EPIs) using the motion-probing gradient (MPG) method were acquired at 1-3 hours and 24-48 hours after occlusion. Apparent diffusion coefficients (ADCs) were calculated from these images in ischemic lesions and in normal unoccluded regions. Results were as follows. 1. Ischemic lesions could be detected on the DW-EPIs at 1 hour after occlusion. 2. The ADC of water in the brain tissue was smaller than that of free water as a result of restricted diffusion. 3. Anisotropic diffusion that probably can be attributed to the myelin sheath was observed in the normal deep white matter. 4. In the ischemic lesions, the ADC decreased rapidly within 1-3 hours after occlusion and then slightly further declined after 24-48 hours. In the ischemic deep white matter, diffusion anisotropy disappeared at 24-48 hours after occlusion. Diffusion-weighted imaging may have applications in the examination of pathophysiological mechanisms in cerebral ischemia by means of evaluation of ADC and diffusion anisotropy.

Animals↗
PubMed1993

Decreased adenylate energy charge and superoxide anion release in polymorphonuclear leukocytes in septic patients after hepatectomy.

To clarify the process of multiple organ failure after hepatectomy, the adenylate energy charge (EC) and superoxide anion (O2-) release of polymorphonuclear leukocytes (PMN) were measured 19 times on 11 septic patients after curative hepatic resection in relation to arterial ketone body ratio (AKBR), which reflects hepatic mitochondrial redox potential. PMN EC was measured by labeling the adenine nucleotide pool of PMN with radioactive adenine. The data of the septic patients (n = 19) was divided into two groups according to the hepatic energy status: AKBR above 0.7 (septic state A; n = 8) and AKBR below 0.7 for at least 3 successive days (septic state B; n = 11). Thirteen nonseptic patients undergoing hepatic resection were applied to the control group, and all of them showed AKBRs higher than 0.7. The PMN EC of septic patients was significantly lower than that of nonseptic patients [0.80 +/- 0.01 (SEM) vs. 0.88 +/- 0.02, P < 0.01]. In septic patients, moreover, the PMN EC of septic state A was significantly higher than septic state B (0.85 +/- 0.01 vs. 0.77 +/- 0.03, P < 0.05). Superoxide anion release of septic patients was significantly lower than that of nonseptic patients (19.0 +/- 2.1 nmol/5 x 10(5) cells/15 min vs. 29.3 +/- 1.7 nmol/5 x 10(5) cells/15 min, P < 0.01). Superoxide anion release of septic state A was significantly greater than that of septic state B (26.0 +/- 2.8 nmol/5 x 10(5) cells/15 min vs. 15.0 +/- 1.9 nmol/5 x 10(5) cells/15 min, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗
PubMed1992

A prolongation of hepatic vascular exclusion by in situ hypothermic perfusion in dogs.

In situ hypothermic hepatic perfusion was performed in dogs to explore whether the time limit of hepatic vascular exclusion could be prolonged. During hepatic vascular exclusion, hepatic hypothermic perfusion was performed via portal vein using various perfusates under active bypass from the portal vein and infrahepatic inferior vena cava area to the superior vena cava system. Dogs receiving hepatic hypothermic perfusion for 1 hour died when given Ringer's solution but survived more than 7 days when given Euro-Collins' and University of Wisconsin solutions. Although dogs tolerated 2 hours of hepatic hypothermic perfusion when give University of Wisconsin solution, all dogs died by 2 hours of hepatic hypothermic perfusion when given Euro-Collins' solution. The hepatic energy charge and arterial ketone body ratio of dogs that died were significantly lower than for those that survived. This suggests that the regimen of hepatic hypothermic perfusion with University of Wisconsin solution is able to maintain the energy metabolism of the liver under hepatic vascular exclusion for prolonged periods, hence, its possible clinical application.

Adenosine↗
PubMed1992

Impaired energy metabolism of lymphocytes in cirrhotics after hepatectomy.

To clarify the mechanism of high susceptibility to infection in cirrhotics, the changes in adenylate energy charge and MTT assay in peripheral blood lymphocytes were studied in cirrhotic and noncirrhotic patients in the early postoperative period after hepatectomy. The adenylate energy charge measured by radioactive labeling of the lymphocyte adenine nucleotide pool showed no significant difference preoperatively between cirrhotics and noncirrhotics, but a significant difference was observed in the pre- and postoperative distribution of adenine nucleotide metabolites (P less than 0.01). In the cirrhotic group, the adenylate energy charge of lymphocytes decreased significantly to 0.807 +/- 0.011 on the third postoperative day compared with preoperative value (0.891 +/- 0.006, P less than 0.01) and was restored to the normal range on the fifth and tenth postoperative days (0.886 +/- 0.006, 0.899 +/- 0.014), while no significant decrease was observed in the noncirrhotic group. MTT assay revealed that lymphocyte cell function decreased significantly in cirrhotics after hepatectomy. These results indicate that, in cirrhotic patients, the energy metabolism of lymphocytes is already impaired to some extent preoperatively, and that it undergoes further deterioration when surgical stress is applied. It is suggested that the decreased energy metabolism in the lymphocyte may be responsible for the increased susceptibility to infection in postoperative cirrhotics.

Adenosine Diphosphate↗
PubMed1992

[Diabetes mellitus as a risk factor in major hepatic resection and its strategy by intraportal insulin administration].

Diabetes mellitus, or insulinopenia, is a possible risk factor in major hepatic resection, because insulin is a typical hepatotrophic factor governing hepatic mitochondrial function. By analyzing 91 hepatic resections for hepatocellular carcinoma, we made a multiple regression equation for prediction of postoperative mortality using insulinogenic index (II) and redox tolerance index (RTI) which were both calculated by measuring insulin level and arterial ketone body ratio during oral glucose tolerance test (z = 3.11 x II + 1.43 x RTI - 2.27). When z was negative, the mortality rate was 33.3% in major hepatic resection cases. Since 1990, we have prospectively applied intraportal insulin administration (IIA) therapy as postoperative management to patients with negative z score. In the total 19 patients the postoperative mortality was significantly reduced by the introduction of IIA therapy. Hence, the IIA therapy can be a strategy against diabetes mellitus as a risk factor in major hepatic resection.

Aged↗
PubMed1991

Hepatic vascular exclusion as a model for complete and stable hepatic ischemia in dogs.

In order to confirm a complete ischemia model, 1-hour warm hepatic ischemia by hepatic vascular exclusion (HVE) was studied in dogs, in comparison with that by inflow occlusion (IOC) only. The splanchnic venous bed and/or infrahepatic inferior vena cava were decompressed by a centripetal pump-driven venovenous bypass. Indocyanine green retention test revealed no hepatic blood flow in the HVE model during ischemia, while hepatic blood perfusion was still present in the IOC model. All 5 of the IOC dogs survived more than 7 days after revascularization, while 4 of the 5 HVE dogs died within 9 h. After the induction of hepatic ischemia, lactate increased in both HVE and IOC dogs. After revascularization, transaminases and guanase were elevated, the arterial ketone body ratio (acetoacetate/3-hydroxybutyrate) decreased and the serum lactate accumulated more in HVE dogs than in IOC dogs. The hepatic redox state of IOC dogs was significantly decreased by additional clamping of the inferior vena cava. It is concluded that the HVE model with a pump-driven active bypass provides complete and stable hepatic ischemia, resulting in greater deterioration of hepatic cellular functions; hence it is more suitable as a model of complete hepatic ischemia than the IOC one.

Animals↗
PubMed1990

Clinical evaluation of a newly developed enteric nutrient given to the neurosurgical patients with disturbances of consciousness.

An enteric nutrient 'SAN-ET-A', rich in protein and electrolytes, was given to 8 patients with disturbances of consciousness. Although the adminstered dosage had a calorie content so low that basal metabolism was barely maintained, the level of serous proteins increased following administration. Electrolyte imbalance was not found, and the patients did not suffer from severe renal or liver dysfunctions. No notable gastrointestinal troubles occurred except in one case. It is concluded that a low dosage of SAN-ET-A was sufficient to maintain the patients in good nutritional condition. Furthermore, it is suggested that this nutrient can be safely given for a long period.

Aged↗
PubMed1990

Arteriovenous malformation at the cervicomedullary junction: a case report with magnetic resonance imaging.

A rare case of arteriovenous malformation at the cervicomedullary junction is reported. A 72-year-old man developed symptoms of total transection of the upper cervical cord without evidence of subarachnoid hemorrhage. The arteriovenous malformation had an intramedullary nidus with an aneurysmal dilatation at the C-1 level. This lesion was diagnosed by magnetic resonance imaging and confirmed at autopsy. The neurological symptoms may have been due to compression of the spinal cord by the intramedullary lesion, followed by degeneration and necrosis. The usefulness of magnetic resonance imaging in the neuroradiological diagnosis is particularly emphasized.

Aged↗