Biomedical subjects
Y Kikuchi
Publications and source records attributed to Y Kikuchi.
Estimation of thermal sensation during varied air temperature conditions.
Seven male students were exposed to four varied air temperature environments: hot (37 degrees C) to neutral (27 degrees C) (HN), neutral to hot (NH), cool (17 degrees C) to neutral (CN), and neutral to cool (NC). The air temperature was maintained at the first condition for 20 min, then was changed to the second condition after 15 min and was held there for 20 min. Each subject wore a T-shirt, briefs, trunks, and socks. Each sat on a chair and was continuously evaluated for thermal sensation, thermal comfort, and air velocity sensation. Some physiological and thermal parameters were also measured every 5 s during the experiment. The correlation between thermal sensation and skin temperature at 15 sites was found to be poor. The subjects felt much warmer during the rising phase of the air temperature (CN, NH) than during the descending phase (HN, NC) at a given mean skin temperature. However, thermal sensation at the same heat flux or at the same value of the difference between skin and air temperature (delta(Tsk - Ta)) was not so different among the four experimental conditions, and the correlation between thermal sensation and heat flux or delta(Tsk - Ta) was fairly good. The multiple regression equation of the thermal sensation (TS) on 15 sites of skin temperature (Tsk; degrees C) was calculated and the coefficient of determination (R*2) was found to be 0.656. Higher coefficients of determination were found in the equations of thermal sensation for the heat flux (H; kcal.m-2.h-1) at the right and left thighs of the subjects and on delta(Tsk - Ta) (degrees C) at 4 sites. They were as follows: TS = 2.04 - 0.016 Hright - 0.036 Hleft; R*2 = 0.717, TS = 1.649 + 0.013 delta(Tsk - Ta)UpperArm - 0.036 delta(Tsk - Ta)Chest - 0.223 delta(Tsk - Ta)Thigh-0.083 delta(Tsk - Ta)LowerLeg; R*2 = 0.752, respectively.
Influence of sustained hypoxia on the sensation of dyspnea.
We assessed the effect of sustained isocapnic hypoxia (PCO2 = 40 Torr, SaO2 = 80%) on the sensation of dyspnea in 16 normal healthy males. Subjects rated the sensation of dyspnea (c) on 15 cm visual analog scales during 20 min of sustained hypoxia. Following this hypoxic period, 8 subjects undertook mild exercise (10-50 W on a bicycle ergometer for 3 min) under the continuation of hypoxia. During sustained hypoxia, psi increased initially with ventilation from 0.6 +/- 0.2 (n = 16, mean +/- SE) to 2.9 +/- 0.6 at peak ventilation, but it decreased with ventilatory depression to 1.6 +/- 0.4. Dyspnea intensity during hypoxic exercise was significantly smaller than that at peak ventilation in the resting hypoxic period (2.3 +/- 0.7 vs. 3.9 +/- 1.0), although the ventilation was greater during exercise (24.0 +/- 3.0 vs. 19.7 +/- 1.4 l/min). These results indicate that sustained hypoxia has a biphasic, i.e., initial stimulatory and delayed depressant, effect on dyspnea and on ventilation. It is suggested that the dyspnea sensing mechanism is suppressed during mild exercise under sustained hypoxia.
Multiple dural arteriovenous fistulas.
Four patients with multiple intracranial dural arteriovenous fistulas (DAVFs) at separate sites were treated by endovascular techniques (transarterial and/or transvenous embolization), surgery (excision or isolation), radiotherapy, or combinations, according to the pathophysiological condition. All lesions in two patients were obliterated completely without neurological deficit. There were residual fistulas after the treatment in two patients, but these were low-grade lesions without retrograde cortical venous drainage, and marked clinical improvement was obtained. Planning of treatment strategies for multiple DAVFs requires careful analysis of the venous drainage from the affected sinuses and cerebral hemodynamics.
Bartonella henselae antibody prevalence in free-ranging and captive wild felids from California.
In order to determine the importance of wild felids in the epidemiology of Bartonella spp. infection, 136 Nobuto strips or serum samples from free-ranging mountain lions (Felis concolor) and bobcats (Felis rufus) captured in California (USA) between 1985 and 1996 were tested for B. henselae antibodies (titer > or = 1:64) using an immunofluorescence test. Similarly, 124 serum samples from 114 captive wild cats representing 26 species or subspecies collected between 1991 and 1995 were retrieved from the serum banks of four California zoological parks. Fifty-three percent (33/62) of the bobcats, 35% (26/74) of the mountain lions, and 30% (34/114) of the captive wild felids (genera Acinonyx, Panthera and Felis) had B. henselae antibodies. In captive wild felids, prevalence varied widely among the species, but seropositivity was more likely to occur in the genus Felis than in the genus Acinonyx or Panthera. Prevalence was evenly distributed between sexes, except for free-ranging mountain lions. Antibody prevalence ranged from 25% in 0- to 2-yr-old captive felids to 35% in cats > or = 9-yr-old, but the highest antibody titers were observed in cats < 5-yr-old.
Experience and clinical usefulness of BACTEC MGIT 960.
Recently, an automatic instrument for culturing acid-fast bacteria in liquid media has been introduced in Japan to accelerate and increase the detection of the bacteria as well as the work e ciency of test lab technicians. We compared the MGIT (Mycobacterium Growth Indicator Tube) method and the two conventional culture methods used in our lab by testing 176 specimens (130 cases) submitted for acid-fast testing between July 27 and September 18, 1998. BACTEC MGIT 960 (Nippon Becton Dickinson) was used in the MGIT method while Ogawa K medium and Kudo PD medium were used for our conventional culture methods. Of the 176 specimens, 26 specimens were MGIT positive, 22 specimens were Ogawa K medium positive, and 21 specimens were Kudo PD medium positive. Among these three culture methods, M. tuberculosis was found in 8 specimens, M. avium was found in 9 specimens, M. intracellulare was found in 4 specimens, and other acid-fast bacteria were found in 5 specimens. It took an average of 13.5 days to detect M. tuberculosis by the MGIT method, 23.0 days by the Ogawa K medium, and 24.3 days by the Kudo PD medium, suggesting that the MGIT method is signi cantly faster than the conventional methods (p < 0.05). The MGIT method took an average of 5.7 days to detect M. avium and M. intracellulare while the two conventional methods required more than 20 days, suggesting that the MGIT method is signi cantly faster than the conventional methods (p < 0.05). The BACTEC MGIT 960 was extremely useful for clinical diagnosis in some of the cases and our results indicated that the MGIT method led to more rapid diagnosis and earlier treatment than the conventional methods.
[Total aortic arch replacement for distal aortic arch aneurysms].
Between January 1991 to April 1997, 13 consecutive patients underwent the total aortic arch replacement for distal aortic arch aneurysms. The operation was performed through the median sternotomy and the cardiopulmonary bypass was instituted with the cannulation of ascending aorta for arterial perfusion and of right atrium for venous return. Then the aortic arch was totally replaced with four limbed artificial graft with the aid of selective cerebral perfusion and open distal anastomosis of the distal end of the aneurysm. The mortality was 16% (2 patients) and these cases had ruptured aneurysm and had deep shock preoperatively. There were no severe cerebral complication. Total aortic arch replacement would be the acceptable procedure for the distal aortic arch aneurysm and antegrade ascending aortic perfusion was useful method to avoid the thromboembolic attack due to the retrograde femoral perfusion.
[Minimally invasive direct coronary artery bypass grafting (MIDCAB) for multivessel disease in a 86 year-old patient].
An 86-year-old male underwent minimally invasive direct coronary artery bypass grafting (MIDCAB) without cardiopulmonary bypass, for severe triple-vessel coronary disease. Left descending coronary artery was anastomosed with the in situ left internal thoracic artery through a limited anterior thoracotomy, and right coronary artery was anastomosed with the in situ right gastroepiploic artery through a small upper laparotomy. The postoperative angiography showed patent grafts, and the patient has been doing well without any complications. MIDCAB is a useful technique even for multivessel coronary diseases in selected cases.
[A case of painless Standford type A acute aortic dissection complicating acute occlusion of the right subclavian artery].
We reported about a rare case of painless Stanford type A acute aortic dissection with the only complaints being numbness and paleness in the right arm. A 68-year-old male who hed been treated in another hospital under the diagnosis of acute occlusion of the right subclavian artery was referred to our hospital because of severe heart failure and shock. After being admitted to our hospital, the patient was diagnosed as Standford type A acute aortic dissection with transesophageal echocardiography and underwent an emergency graft replacement of the ascending aorta and total aortic arch. The postoperative course was uneventful and the patient was discharged without any complications.
[Pharmaceutical and pharmacological development of antitumor prostaglandins].
Antitumor Prostaglandins such as delta 12PGJ2 and delta 7PGA1 possess a cross-conjugated dienone unit and exhibit unique antitumor effect. Lipid microshere (w/o type emulsion) was selected as pharmaceutical formulation because of physicochemical properties of prostaglandin. 13,14-Dihydro-15-deoxy-delta 7-PGA1 methyl ester (TEI-9826) were selected as a candidate for clinical trial. In a rat and mouse serum in vitro, TEI-9826 rapidly metabolized to 13,14-dihydro-15-deoxy-delta 7-PGA1 (TOK-4528), but TOK-4528 is stable as well as delta 12PGJ2. Lipid microshere containing TEI-9826 at the content of 5 mg/ml exhibited administration route and schedule dependent antitumor effect in vivo using Colon 26 bearing mouse model, which suggested that duration of serum concentration was important for antitumor effect. One of the antitumor mechanism of antitumor PG might be an induction of the cyclin-dependent kinase inhibitor p21. PPAR gamma also might be important. New type homogenizer, high pressure jet flow type homogenizer was developed in the study of antitumor prostaglandin.
[The early results of the minimally invasive direct coronary artery bypass (MIDCAB)].
The clinical experiences of 29 consecutive MIDCAB procedures performed at our institution between October, 1996, and October, 1997, were analyzed. Preoperative patient's characteristics were as follows; LAD single vessel disease: 25, double vessel disease: 1, triple vessel disease: 1, RC single vessel disease: 1, LMT lesion: 1, concomitant procedures: 2 (ASO: 1, AAA: 1). LITA harvesting was performed using the video-assisted thoracoscopy in initial 4 patients, and in last 10 patients we used the specially designed retractor THORALIFT (Autosuture Co., Ltd.) for harvesting LITA by direct vision. LAD was stabilized mechanically using the stabilizer when we performed the anastomosis in last 10 patients to enhance the quality of the anastomosis. The patency rate was 96%, but there were two patients (6%) who had the stenosis of the anastomosis site. Coronary artery occlusion time was 13.2 minutes in the mean. We also studied the hemodynamics of blood flow in LITA grafts with the aid of 7.5 MHz transthoracic duplex imaging in these MIDCAB patients and compared with the LITA grafts in conventional CABG performed in same periods. There were no statistical differences between the two groups about the graft flow and velocity. We conclude that MIDCAB would be an alternative procedure that can be performed with low risk and acceptable early results in selected patients.
[A case of Poland's syndrome with giant bulla resected by using autologous fascia lata].
We reported a case of giant bulla with Poland's syndrome, only left pectoral major and minor muscles defect. A 58-year-old man was admitted to our hospital with shortness of breath on exertion. Computed tomographic scan revealed right giant bulla in emphysematous lung. The giant bulla was resected by linear stapler with autologous fascia lata. Though minor air leakage persisted for 5 postoperative days, the postoperative course was uneventful. It could be effective to reinforce staple line by using autologous fascia lata in emphysematous bulla without any infectious problem.
[Minimally invasive direct coronary artery bypass grafting (MIDCAB) for re-operation in a 85 year-old patient].
An 85-year-old male, who had undergone aorto-coronary bypass grafting to left anterior descending coronary artery (LAD) using saphenous vein graft (SVG) seventeen years before, was operated with minimally invasive direct coronary artery bypass grafting (MIDCAB) without cardiopulmonary bypass. LAD was anastomosed with the in situ left internal thoracic artery through a limited anterior thoracotomy. The postoperative angiography showed patent graft, and the patient has been doing well without any complications. MIDCAB is a useful technique even for re-operation of coronary diseases in selected cases.
[The long-term results of surgical treatment for acute type A aortic dissection].
Between 1992 and 1996, 31 patients with acute type A aortic dissection underwent the surgical treatment on an emergency basis. The overall early mortality rate was 12.3% (4 patients), and the overall 5-year survival rate (calculated by Kaplan-Meier method) was 76.9% respectively. Although there is controversy about the operative procedure whether the aortic arch should be replaced or not in aortic arch dissection in which the primary intimal tear is located at or extends into the arch, the resection of the aortic arch tear and simultaneous arch repair with graft replacement of the ascending aorta would be the acceptable procedure in the long term period with the recent improvement of adjunct technique for the prevention of cerebral ischemia and heart protection. The composite graft replacement of the aortic root is also indicated in patients with acute dissection associated with annuloaortic ectasia or Marfan's syndrome and severely destroyed aortic root with the extension of dissection to the aortic root with acceptable mortality and survival rate in the early and late period.
[Successful surgical treatment for severe mitral valve annulus enlargement and mitral regurgitation 5 years after aortic root replacement in Marfan syndrome: a case report].
Major cardiovascular lesions associated with Marfan syndrome include aortic diseases such as aortic root dilatation and mitral disease. If untreated, cardiovascular manifestations of the Marfan syndrome cause death in one half of patients during the first four decades of life. Although aortic diseases in the Marfan syndrome are responsible for most of serious morbidity and mortality, 60-80% of patients with Marfan syndrome have mitral valve dysfunction. The results of surgical treatment for aortic diseases in Marfan patients have recently shown significant improvement. However, there is no acceptable consensus about the timing and the technique of surgical intervention for mitral diseases. Especially mitral valve diseases is the most common cause of morbidity and mortality in infants with the Marfan syndrome. We report herein a case of Marfan syndrome (21-year-old female) who had undergone two operations for aortic root dilatation five years before she underwent the surgical treatment for progressive heart failure due to severe mitral annulus enlargement and mitral regurgitation.
[Detection of parafoveal scotoma by multifocal electroretinograms].
We investigated the relation between multifocal electroretinograms (M-ERGs) and artificial parafoveal scotoma. M-ERGs were recorded from normal subjects using a circular piece of black paper attached to a monitor. Lower response density around the 10 to 15 degree parafovea region was not observed up to 3 degree scotoma (visual angle), but was detected above 5 degree scotoma in field topography of M-ERGs. The shape of the scotoma in field topography was not circular but somewhat oval. The results from two cases of parafoveal retinal degeneration were in good accordance with this basic study in normal subjects. We proved that detection of parafoveal scotoma by M-ERG is limited in comparison with the results obtained by automated static perimetry.
Mesenteric venous thrombosis: a case report.
We describe herein a 41-year-old man who complained of abdominal pain. He underwent surgery, and the diagnosis of mesenteric venous thrombosis was made. The small intestine, mainly the jejunum, presented necrosis on laparotomy, and a 155-cm long segment of it was successfully resected. Anticoagulant therapy was initiated postoperatively, and he is well at present.
[Cancer-associated gene abnormalities and chemosensitivity].
One of the most important clinical issues in cancer chemotherapy is the presence of intrinsic resistance or the appearance of acquired resistance against chemotherapy. As for intrinsic resistance, we had to perform direct chemo-sensitivity testing, or had to rely on the knowledge empirically acquired from randomized clinical trials. However, molecular or genetic markers associated with chemo-sensitivity have been reported recently. For example, inactivation of p53 or GML gene has been reported to be associated with chemo-resistance. Overexpression of topo-isomerase I has been reported to be associated with chemo-sensitivity to Topo I inhibitor. Overexpression of Thymidine Phosphorylase has been found to be associated with chemo-sensitivity to prodrug of 5-FU. By checking the status of such chemo-sensitivity markers prior to chemotherapy, it would be possible to predict the chemotherapeutic effect and even the necessity of the chemotherapy in the near future. In this article, we review the chemo-sensitivity markers reported so far, and methodology contributing to the discovery of new chemo-sensitivity markers. As a clinical study, 11 cases of ovarian cancer with high sensitivity to cisplatin-based chemotherapy and 29 cases of ovarian cancer with chemoresistance were analyzed by Comparative Genomic Hybridization (CGH). Copy number decrease in Xp, and copy number increase in 19q were observed in 13, 12 out of 29 resistant cases (45, 41%) and zero, 1 out of 11 sensitive cases (0, 9%), suggesting that -Xp and +19q were likely to be a genetic event associated with intrinsic drug-resistance (p = 0.006, 0.05, respectively). This effort should contribute to the discovery of new chemo-sensitivity and resistance markers.