Biomedical subjects

N Kaku

Publications and source records attributed to N Kaku.

At least 19 recordsLinked to original sources

PubMed2005

Carcinosarcoma of the parotid gland: an unusual case with large-cell neuroendocrine carcinoma and rhabdomyosarcoma.

We report a case of carcinosarcoma of the parotid gland in a 72-year-old Japanese man. The patient noticed a rapidly enlarging hard mass in the right parotid gland. He underwent radical parotidectomy with cervical lymph node dissection. The resected tumor measured 3.5 x 4.5 cm and histopathologically showed carcinomatous and sarcomatous components. The carcinomatous component consisted of large-cell neuroendocrine carcinoma (LCNEC), squamous cell carcinoma and adenocarcinoma not otherwise specified, while the sarcomatous component included spindle cell sarcoma not otherwise specified, so-called myxosarcoma and rhabdomyosarcoma. The LCNEC component was predominant within the whole tumor. The diagnoses of LCNEC and rhabdomyosarcoma were also confirmed immunohistochemically. With regard to histopathogenesis, based on the lack of histopathological evidence and antecedent history of pleomorphic adenoma, we considered the present case to be de novo, not expleomorphic adenoma.

Aged↗

PubMed2005

Does the self-centering mechanism of bipolar hip endoprosthesis really work in vivo?

PURPOSES: To examine radiographically the component motion in a bipolar prosthesis and to determine whether the self-centering mechanism really works in vivo. METHODS: 38 patients with 41 bipolar hip endoprostheses (30 for coxarthrosis and 11 for osteonecrosis of femoral head) were included in this study. Two radiographs of each case were taken to evaluate the self-centering mechanism. The first anteroposterior radiograph of both hip joints was taken at the maximum abduction while the patient standing on the endoprosthetic leg. The second radiograph was taken after the patient returned to neutral position while standing on 2 legs. In the present study, the order in which the radiographs were taken differed from previously reported studies. The radiographs were analysed using the method similar to that of Drinker and Murray. The adductive motion from abduction to a neutral position is within the range of inner bearing oscillation. RESULTS: The outer head alignment changed from 23 degrees to 12 degrees in the patients with osteonecrosis. However, the valgus position of the outer head (36 degrees) remained unchanged in the patients with coxarthrosis standing on 2 legs in the neutral position. CONCLUSION: The self-centering mechanism of the bipolar endoprosthesis functioned in the patients with osteonecrosis, but did not work in the coxarthrosis group.

Arthroplasty, Replacement, Hip↗

PubMed2005

Expression of beta-catenin, E-cadherin and cyclin D1 in adenoid cystic carcinoma of the salivary gland.

We evaluated the expression of beta-catenin, E-cadherin, and cyclin-D1 in 23 cases of adenoid cystic carcinoma (ACC) of the salivary gland. We detected beta-catenin on the cell membranes in all ACCs, but its distribution was irregular, as compared to that on normal structures. In three out of the 23 cases, beta-catenin was detected in the nuclei, as well as on cell membranes. Polymerase chain reaction (PCR) and direct sequencing revealed a missense mutation in one case in which beta-catenin had been detected in the nuclei of tumor cells. We also detected E-cadherin on cell membranes with a similar irregular distribution to that of beta-catenin. In 11 cases (almost 48%) of ACC, cyclin D1 was localized in cell nuclei but there was no correlation with the nuclear staining of the beta-catenin. Our results suggest that disturbances in the distribution of beta-catenin and E-cadherin might affect the morphology ofACC and that a small fraction of cases of ACC are characterized by a mutation in the beta-catenin gene, which is associated with the nuclear accumulation of the product of this gene but does not affect the transcription of the gene for cyclin-D1.

Base Sequence↗

PubMed2004

Biomechanical properties of heat-treated bone grafts.

INTRODUCTION: A possible critical complication associated with banking bone is human immunodeficiency virus (HIV) infection. Recently, since the report of HIV infection in bone allografts from an HIV-seronegative donor, a more reliable method of sterilization for preserved bone graft has become necessary. Heat treatment of banking bone is one of the simple sterilization methods. This method is especially safe and practical for the prevention of HIV infection. MATERIALS AND METHODS: We previously reported a biological study on heat-treated bone graft. In that study, we showed that revascularization and new bone formation of bone graft after heat treatment at 60 degrees C was nearly the same as that of non-heat-treated bone graft, while at 100 degrees C, revascularization and new bone formation showed a significant delay. This time, we examined the change of mechanical strength of heat-treated bone grafts after transplantation in an experiment. To eliminate the problem of antigenicity of grafted bone, we used autografts, not allografts. Two types of heat-treated autografts were employed: heat-treated at 60 degrees C for 30 min and heat-treated at 100 degrees C for 5 min; as a control, fresh autografts were replaced in the left femur of rabbits. A strength test was performed for both the transplanted bone and the untreated intact right femur with time after transplantation. The strength test consisted of a compression test and torsional test, and the strength was compared between transplanted bone and the untreated intact right femur. RESULTS: In the compression test, the grafts heat-treated at 60 degrees C showed a strength ratio before transplantation of 97.3%. The strength ratio decreased to 63.5% at 18 weeks after transplantation. Then the strength ratio increased and recovered to 94.5% at 48 weeks after transplantation. However, the grafts heat-treated at 100 degrees C showed unsatisfactory mechanical strength, at 48 weeks the strength ratio was 60.1%, which was significantly lower compared with controls. In the torsional test, the grafts heat-treated at 60 degrees C showed almost the same strength observed in the compression test. However, the grafts heat-treated at 100 degrees C showed unsatisfactory mechanical strength: at 48 weeks, the strength ratio was 57.3%. CONCLUSION: Therefore, heat treatment at 60 degrees C is a useful sterilization method, not only in biological but also mechanical terms.

Animals↗

PubMed2003

3M integral bipolar cup system for dysplastic osteoarthritis. Clinical and radiographic review with five- to seven-year follow-up.

Between 1995 and 1997 we undertook 40 bipolar hip arthroplasties in 35 patients with dysplastic osteoarthritis. The steep and shallow acetabulum was excavated and the bipolar socket was placed high with an adjustment of leg-length. At follow-up of between five and seven years, there were 19 excellent, 16 good and five fair results according to the scoring system of Merle d'Aubigné and Postel. The mean radiographic superior migration of the bipolar socket was 2.1 mm (0 to 10). Osteolysis was noted in three hips within three years of the operation. Abduction on weight-bearing was recorded in 24 hips and the bipolar system was found to be functioning predominantly between the inner bearing and the metal femoral head in 20.

Adult↗

PubMed2001

Management of severe blunt liver injuries.

To assess the effectiveness of non-surgical treatment for severe blunt liver injuries, we retrospectively examined the files of 147 patients (excluding cases with cardiopulmonary arrest on arrival). The patients were divided into three groups according to the date of admission: Group-A (1982-85), B (1986-90) and C (1991-95). The patients were further divided on the basis of the type of injury, according to the classification proposed by the Japanese Association for the Surgery of Trauma (JAST). The types of injuries reported here were of type II, IIIa or IIIb. There was no difference in the patients' background, injury severity score (ISS), amount of intra-peritoneal hemorrhage, and amount of blood transfusion among the three groups, A, B and C. Surgical treatment was carried out in all Group-A patients, in 81.8% of Group-B patients and in 31% of Group-C patients. The hospitalization period was shorter in the Group-C, and the frequency of fatal outcome was also lower in Group-C. Non-surgical treatment has been performed since 1988 in our center, and its frequency has been increasing since then. It was applied to 6 cases (18.2%) of Type II injuries in Group-B. In total, 69% of the cases in Group-C were non-surgically treated, including cases of Type IIIa and Type IIIb injuries. Non-surgical treatment prevented 8 out of 9 cases of severe liver injury from having fatal outcomes in 1995. Moreover, 5 of those cases were of the most serious type (Type IIIb). There were three fatalities in Group-C and none in Group-B. Out of all the non-surgically treated cases, injuries to the head were the cause of fatality. Any treatment of cases showing inferior vena cava damage was generally ineffective due to heavy bleeding, unless the bleeding was stopped by surgical intervention. Non-surgical treatment is suitable for blunt liver injuries, including severe liver injuries, provided that bleeding control and close observation are maintained.

Adult↗

PubMed2001

Lipid extracted freeze-dried bank bone sterilized with low temperature plasma.

Ethylene oxide gas (EOG) is widely used for sterilization of freeze-dried bone. Recently EOG is regulated for clinical use because of cytotoxicity and environmental pollution concerns. Low Temperature Plasma Sterilization (LTPS) has no toxicity and mutagenicity working with a hydrogen peroxide gas plasma at 45 degrees centigrade. We have now used this method experimentally and clinically to sterilize freeze-dried bone. Cortical bone with a thickness of 5 mm and cancellous bone with a 10 mm cubic size were prepared, washed, defatted, dehydrated by freeze drying and finally sterilized by LTPS. As a Microbiological test, defatted freeze-dried bone was contaminated with B. subtilis, and after then the contaminated bone was treated with LTPS and the bacteria was proven inactive. Mechanical testing on rabbit cortical bone was investigated by compression testing using a mechanical testing machine. No differences between EOG treated and LTPS treated bone were found. From December 1996, 52 patients who had small and middle bone defects were treated with defatted, freeze-dried and LTPS sterilized bone. Clinical result was good. No deep infections, no transmission of virus infections or severe graft absorption were noted. The LTPS bank bone is safe and useful to reconstruction to small bone defects.

Bone Banks↗

PubMed2000

Effects of overexpression of Escherichia coli katE and bet genes on the tolerance for salt stress in a freshwater cyanobacterium Synechococcus sp. PCC 7942.

To explore the potential role of catalase and glycine betaine in the protection of cyanobacteria from damage due to salt stress, we transformed a freshwater cyanobacterium Synechococcus sp. PCC 7942 with shuttle vectors that contained the Escherichia coli katE, bet, and katE plus bet (katE/bet) genes. The catalase activity in the cells overexpressing katE and katE/bet genes was about 1.4-1.8-fold higher than that in the control cells. The control and transformant cells had a similar growth rate in the medium with a low salinity. However, under a high-salinity condition, the cells transformed with katE grew faster than the control cells, and the cells expressing katE/bet genes grew faster than those expressing either the katE or bet gene alone. These results indicate that high-salinity caused oxidative stress and the coexpression of katE and bet genes in Synechococcus cells were superior to the expression of either katE or bet alone for the protection of the cells from the damage due to high-salinity.

Journal Article↗

PubMed1999

Molecular characterization of DnaK from the halotolerant cyanobacterium Aphanothece halophytica for ATPase, protein folding, and copper binding under various salinity conditions.

Previously, it was found that the dnaK1 gene of the halotolerant cyanobacterium Aphanothece halophytica encodes a polypeptide of 721 amino acids which has a long C-terminal region rich in acidic amino acid residues. To understand whether the A. halophytica DnaK1 possesses chaperone activity at high salinity and to clarify the role of the extra C-terminal amino acids, a comparative study examined three kinds of DnaK molecules for ATPase activity as well as the refolding activity of other urea-denatured proteins under various salinity conditions. DnaK1s from A. halophytica and Synechococcus sp. PCC 7942 and the C-terminal deleted A. halophytica DnaK1 were expressed in Escherichia coli and purified. The ATPase activity of A. halophytica DnaK1 was very high even at high salinity ( 1.0 M NaCl or KCl), whereas this activity in Synechococcus PCC 7942 DnaK1 decreased with increasing concentrations of NaCl or KCl. The salt dependence on the refolding activity of urea-denatured lactate dehydrogenase by DnaK1s was similar to that of ATPase activity of the respective DnaK1s. The deletion of the C-terminal amino acids of A. halophytica DnaK had no effect on the ATPase activity, but caused a significant decrease in the refolding activity of other denatured proteins. These facts indicate that the extra C-terminal region of A. halophytica DnaK1 plays an important role in the refolding of other urea-denatured proteins at high salinity. Furthermore, it was shown that DnaK1 could assist the copper binding of precursor apo-plastocyanin as well as that of mature apo-plastocyanin during the folding of these copper proteins.

Adenosine Triphosphatases↗

PubMed1996

Morphological and histochemical study of nonhemiplegic muscle in acute stroke patients manifesting respiratory failure.

There is little information on skeletal muscle changes in patients with acute stroke. We performed morphological and histochemical examinations of nonhemiplegic sternothyroid muscles biopsied at the time of tracheostomy from 13 patients with acute stroke manifesting acute respiratory failure. Degenerating and regenerating fibers were observed in all 13 specimens. Following characteristic myopathic changes suggestive of mitochondrial abnormalities were also demonstrated in a majority of patients. Namely, ragged-red fibers, focal increase in NADH-TR activity in subsarcolemmal areas and increases in acid phosphate activity were found. The changes were similar but extremely slight in control patients with acute respiratory failure due to causes other than stroke and were absent in the other control patients with adenomatous thyroid tumor. The severity and extent of the histopathological changes in the muscle fibers in patients with acute stroke were closely correlated with the duration of hypoxemia but not with such items as type of stroke, site of cerebral lesion, consciousness level, days of biopsy after the stroke, clinical outcome, levels of serum creatine kinase, myoglobin and PaO2. This acute nonhemiplegic muscle involvement was considered to be a very common complication in severe stroke patients.

Acute Disease↗

PubMed1996

Two survival cases of alcoholic lactic acidosis complicated with diabetes mellitus and alcoholic liver disease.

We have experienced two patients with alcoholic lactic acidosis complicated with liver disease and diabetes mellitus who were successfully treated. They developed hypoglycemia, dehydration, lactic acidosis, and renal failure after drinking a large volume of alcohol without eating for 1 week before onset. Acidosis was thought to be directly related to excessive alcoholic intake, because it was no associated with severe liver failure and rhabdomyolysis. During monitoring of respiratory and circulatory functions, a rapid infusion of fluids adjusting to water and electrolyte imbalance was performed. A mixture of physiological saline and 5% glucose solution was thought to be effective in these cases. Patients recovered from renal failure and lactic acidosis without hemodialysis. Our experience will hopefully provide a key to successful treatment of fatal alcoholic lactic acidosis.

Acidosis, Lactic↗

PubMed1995

Prognostic value of electroencephalogram (EEG) in anoxic encephalopathy after cardiopulmonary resuscitation: relationship among anoxic period, EEG grading and outcome.

We studied the prognostic applicability of electroencephalograms (EEGs) of seventy-nine patients within 24 hours after successful cardiopulmonary resuscitation. The EEGs were classified into five grades according to a modified Hockaday's scale. The EEGs of grades I and II implied full recovery, while those of grade III gave a varied but generally unfavorable prognosis. Patients with grades IV and V EEGs survived in a vegetative condition or died without awakening. Eighteen patients showed EEG with periodic patterns, all of which led to a fatal or vegetative outcome. One case showed EEGs associated with periodic triphasic waves and repetitive sharp transients in the same record. Several cases showed EEGs with different periodic patterns in consecutive records. We conclude that an EEG is a good indicator of patient prognosis after cardiopulmonary resuscitation. However, the clinical significance of morphological differences of various periodic patterns that can occur during an EEG remains to be established.

Adult↗

PubMed1994

Clinical evaluation of severe ischemic limbs by tissue reflection spectrophotometry.

The clinical usefulness of tissue reflection spectrophotometry in the prognosis of ischemic limbs was evaluated. The diseased group (n = 12) consisted of 7 cases of femoral artery thrombosis, 4 cases of chronic obstructive arteriosclerosis and 1 case of femoral vein thrombosis. The normal control group consisted of 14 limbs in 7 normal subjects (n = 14). Index of tissue hemoglobin concentration (IHb) was 37.3 +/- 4.5 (n = 14) in the normal control group and 38.5 +/- 16.9 (n = 12) in the diseased group, which was not significantly different. In a subgroup of patients who required amputation or developed necrosis (severe subgroup), the value was 54.2 +/- 1.7 (n = 6). This was significantly higher than the value of 22.8 +/- 8.5 (n = 6) obtained in a subgroup of patients who received the conservative treatment of thrombectomy (mild subgroup) (p < 0.05). Index of tissue oxygen saturation (ISO2) was 28.0 +/- 4.9 (n = 14) in the normal control group, and 9.1 +/- 2.7 (n = 12) in the diseased group (p < 0.05). ISO2 was 7.0 +/- 1.6 (n = 6) in the severe subgroup which was significantly lower than 11.2 +/- 1.9 (n = 6) in the mild subgroup (p < 0.05). Tissue reflection spectrophotometry therefore appears to provide clinically useful information for the prognosis of ischemic limbs.

Adult↗

PubMed1993

[A case of spontaneous rupture of the ascending aorta].

We report a rare case of spontaneous rupture of the ascending aorta without any evidence of aneurysm formation or aortic dissection. A woman aged 64 was admitted to our cardiac care unit as an emergency patient with severe chest pain. Her face was pale and systolic blood pressure was 70 mmHg in spite of intravenous administration of dopamine (10 micrograms/kg/min). She had a history of hypertension for two years under good medical control. No trace of the chest trauma was noted before her admission. Physical examination revealed neck vein engorgement and distant heart sounds. Chest X-ray film showed enlargement of the cardiac silhouette. ECG showed no evidence of acute coronary syndrome. Pericardial effusion with a floating hematoma-like mass was detected by 2-dimensional echocardiogram. Pericardiocentesis revealed bloody pericardial fluid (Ht: 26%). Aortagraphy was performed resulting in a clinical diagnosis of acute aortic dissection, but there were no signs of a false lumen, aneurysm formation or extravasation of the contrast medium. Although continuous pericardial drainage was performed, she suddenly lost consciousness, collapsed and died. A longitudinal intimal laceration 5 cm long was observed in the ascending aorta. Pathological examination revealed cystic medial necrosis and irregularity of the elastic fibers in the media. No atheromatous plaque was noted in the intima. Spontaneous rupture of the aorta is a life-threatening condition that requires urgent surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

Severe Guillain-Barré syndrome in aged patients: the effect of plasmapheresis.

We report two aged patients with Guillain-Barré syndrome (GBS), in whom the rapid progression necessitated the use of a respirator. The first case, a 72-year-old woman, needed a respirator on the 5th day after onset of illness and the second case, a 74-year-old woman, needed a respirator on the 23rd day. We treated the first patient with plasmapheresis; the second patient underwent plasmapheresis as well as a large dose of intravenous methylprednisolone. Both patients showed remarkable recovery and did not need the respirator from the early stages. It was suggested that plasmapheresis is beneficial for treatment of aged patients with severe GBS, who necessitate the support of a respirator, because it prevents the decline in functional status by shortening the period of hospitalization.

Aged↗

PubMed1992

Two fatal cases of hepatitis B virus carriers after corticosteroid therapy for bronchial asthma.

We report two hepatitis B virus (HBV) carriers who had liver failure after withdrawal of corticosteroids (steroids) administered for treatment of serious asthmatic attacks. Liver functions deteriorated 1 to 2 wk after withdrawal of the steroid therapy and liver failure occurred. Steroid readministration and intensive therapy for liver failure did not prevent death. An excessive immune response provoked by steroid withdrawal and decreased reserve capacity due to underlying chronic liver disease were thought to be factors in the liver failure. Caution must be exercised in the administration of steroids to patients with underlying chronic HBV infection to prevent exacerbation of hepatitis. Prompt readministration of steroids is indicated if evidence of liver failure develops.

Aged↗

PubMed1992

Comparison of incidence, mortality and treatment of acute myocardial infarction in hospitals in Japan and China.

Acute myocardial infarction (AMI) is one of the most intractable diseases and is increasing rapidly in Japan and China. Two hospitals in Japan and China, the Critical Care Center of Kurume University Hospital and the Chinese Beijing 309 Hospital in China (abbreviated to Beijing 309 Hospital) were compared. The incidence, mortality and treatment of AMI were investigated in both hospitals from 1989 to 1991. The incidence of AMI for all patients admitted during the three years was 5% in Kurume University Hospital and 4.7% in Beijing 309 Hospital, which are similar rates. The average age of the patients in Beijing 309 Hospital was younger (58 +/- 13) than in Kurume University Hospital (64 +/- 11). The mortality rate in Kurume University Hospital was slightly lower than the rate in Beijing 309 Hospital (8.1% vs 8.9%). Thrombolytic therapy was actively performed in both hospitals. In Kurume University Hospital, urokinase (UK: 71.4%) or recombinant tissue plasminogen activator (rt-PA: 28.6%) was administered by intravenous (85.7%) and intracoronary percutaneous transluminal coronary recanalization (PTCR: 14.3%) injection. In Beijing 309 Hospital, UK (32.7%) or snake poison enzyme (SPE: 62.3%) was administered by intravenous (85.8%) or intra-aortic (14.2%) injection. Rt-PA was only used in Japan and SPE was only used in China, but both had very strong fibrinolytic effects and resulted in high success rates of coronary reperfusion. The incidence of direct coronary intervention with percutaneous transluminal coronary angioplasty (PTCA) and intra-aortic balloon pumping (IABP) for cardiogenic shock was much higher at Kurume University Hospital than at Beijing 309 Hospital.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

[Emergency manual aspiration for severe hypertensive cerebellar hemorrhage].

We treated 16 patients with hypertensive cerebellar hemorrhage and coma, or deep coma. Their ages ranged from 44 to 79 years (mean age: 66.3 years). Manual aspiration was performed in 9 patients and suboccipital craniectomy was performed in 7 patients. The difference in outcome between the manual aspiration group and the suboccipital craniectomy group with severe hypertensive cerebellar hemorrhage was then evaluated. Manual aspiration was performed for 4 patients in coma, and 5 in deep coma, with a mean age of 69.0 years. The average size of the hematoma was 48.7mm and the mean volume was 31. 7ml on CT scan. The mean interval from admission to operation was about 60 minutes. The mean aspiration rate was 79.6% and 7 patients (77.8%) had a good response to drainage. The suboccipital craniectomy patients included 5 in coma, and 2 in deep coma, with a mean age of 63.4 years. The average size of the hematoma was 51.1 mm and the mean volume was 33.1 ml on CT scan. The mean interval from admission to operation was about 112 minutes and the mean evacuation rate was 86.4%. The results were as follows: 1) After manual aspiration, 5 patients (55.6%) had a good outcome and 2 patients (40%) with deep coma showed good recovery. In contrast, after suboccipital craniectomy only 2 patients (28.6%) had a good outcome and all of the deep coma patients showed poor recovery. 2) The outcome may be most strongly influenced by the duration from admission to operation. 3) All patients with a hematoma volume of over 30 ml had a poor outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗