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Biomedical subjects

N Nishikimi

Publications and source records attributed to N Nishikimi.

At least 37 records · Page 2Linked to original sources
PubMed1999

Implantation of an endovascular covered stent-graft for distal aortic arch aneurysm via midsternotomy under pigtail catheter guidance.

We implanted an endovascular covered stent-graft for distal aortic arch aneurysm involving the left subclavian artery in 12 cases. A stent-graft was delivered just below the aneurysm via aortotomy with direct vision using a 12 F delivery sheath under guidance of a pigtail catheter placed via the groin artery. The proximal anastomosis of the stent-graft was performed with inclusion technique, and the aortotomy was then closed with it. This technique reduces operative damage by eliminating distal anastomosis and should reduce operative mortality and morbidity.

Adult↗
PubMed1999

A rabbit model of abdominal aortic aneurysm associated with intimal thickening.

A model of abdominal aortic aneurysm with intimal thickening was developed in the rabbit. A segment of the abdominal aorta just proximal to the bifurcation (1 or 2 cm in length) was dissected and isolated with clamps. This segment was perfused by injecting physiologic saline or 100 U/ml of hog pancreatic elastase from the lumen. Perfusion was performed manually for 5 min and the peak pressure in the segment was between 300 and 400 mm Hg in order to cause aortic wall injury. After 4 weeks, animals that had received perfusion with elastase had aneurysms in the perfused segment on arteriography. None of the other animals developed aortic aneurysms. Histologically, the segments of aorta perfused with saline exhibited intimal hyperplasia. In addition to the intimal hyperplasia, the segments of aorta perfused with elastase solution showed lysis of the elastic lamellae in the media that resulted in aneurysm formation.

Animals↗
PubMed1999

[Preprocedural and procedural imaging modalities for transluminally placed endovascular grafting].

The vascular system can be evaluated with computed tomography (CT), magnetic resonance angiography (MRA), angiography, and computer-based CT image processing systems before successful transluminally placed endovascular grafting (TPEG). Noninvasive modalities are useful, but angiography is mandatory to determine whether TPEG is indicated. During the procedure, fluorography with a wide-image intensifier and high-resolution digital subtraction angiography are known to be essential, but intravascular ultrasonography is also indispensable to achieve accurate TPEG.

Aortic Aneurysm↗
PubMed1998

Vena cava occlusion with balloon to control blood pressure during deployment of transluminally placed endovascular graft.

Transluminally placed endovascular graft (TPEG) replacement has been applied to treat various aortic diseases. At the moment of deployment, TPEG receives a pressure pulse force to shove it distally, which possibly results in misplacement. Moreover, deploying the TPEG in the aorta increases cardiac afterload, which may damage myocardial function. To avoid these risks, we developed a new technique to control blood pressure by almost complete venous return occlusion. Two occlusion balloon catheters are inserted into the superior and inferior vena cava via the femoral vein. TPEG is deployed at the proper position during inflation of the vena cava balloon to maintain a blood pressure as low as 60 mm Hg by cardiac preload blockage. We, thus far, have not experienced even a trivial sequela with this technique.

Aortic Diseases↗
PubMed1998

Aortic stump closure with a titanium permanent clamp: a useful emergency method.

Successful aortic stump closure in a patient with Behçet's disease was accomplished with a permanent titanium clamp. In May 1990, a saccular infrarenal abdominal aortic aneurysm was detected in this patient, and prosthetic graft replacement was carried out. One year later, this graft was removed because of perigraft fluid collection; the aortic stump was sutured closed, and a right axillobifemoral bypass was done. In November 1994, the patient was admitted to the hospital because of an aortoenteric fistula. An emergency operation was performed, and the aortic stump was managed successfully with a permanent clamp. In patients with Behçet's disease, use of a permanent clamp may offer an alternative to traditional methods for closing blown-out aortic stumps.

Anastomosis, Surgical↗
PubMed1998

Correlation of the anatomical distribution of venous reflux with clinical symptoms and venous haemodynamics in primary varicose veins.

AIM: The aim of this study was to correlate the anatomical distribution of venous reflux with clinical symptoms and venous haemodynamics in patients with primary varicose veins. METHODS: Venous reflux was examined using duplex colour Doppler ultrasonography in 266 legs in 191 patients. The venous refilling and reflux times were also measured. RESULTS: Of the 266 legs, 82 per cent had reflux in the long saphenous vein (LSV), 26 per cent in the short saphenous vein (SSV), 62 per cent had incompetent perforators (IPs) in the calf and 48 per cent had reflux in the deep veins. LSV reflux combined with SSV reflux and/or IPs was associated significantly with severe venous disease and abnormal venous haemodynamics. Femoropopliteal reflux played a role in the development of venous eczema and ulcers when combined with superficial venous reflux. CONCLUSION: Patients at high risk of developing complications of venous disease may be identified by an accurate non-invasive evaluation of reflux patterns.

Adolescent↗
PubMed1998

Attenuation of renal ischemia-reperfusion injury in rats by allopurinol and prostaglandin E1.

50 Sprague-Dawley rats were used to study the effect of allopurinol and prostaglandin E1 (PGE1) on renal ischemia-reperfusion injury. They underwent left renal ischemia for 1 h and reperfusion. A right nephrectomy was performed, and 5 groups were made. Group AP received allopurinol 50 mg/kg and PGE1 20 micrograms/kg; group A, allopurinol; group P, PGE1; group C, control, and group S, sham group. Five animals from each group were used to study renal functions and 5 for renal histology. The serum creatinine values were lower in the treatment groups compared to the controls on days 1-3 and 7 (p < 0.05). The blood urea nitrogen values showed a similar trend. Maximum histological damage was seen in group C, followed by groups A, P and AP, in this order. We conclude that allopurinol and PGE1 attenuate renal ischemia-reperfusion injury in rats.

Allopurinol↗
PubMed1998

Decrease in prevalence of Buerger's disease in Japan.

BACKGROUND: Buerger's disease is a peripheral arterial occlusive disease that is becoming rare in Western countries but is more common in Asia. Whether it is a specific disease entity remains controversial. This study was undertaken to investigate changes in the prevalence and characteristics of Buerger's disease at a major institution in Japan. METHODS: Patients with Buerger's disease admitted to Nagoya University Hospital between January 1985 and December 1996 were studied retrospectively. Buerger's disease was diagnosed on admission according to Shionoya's clinical criteria. RESULTS: A total of 105 patients with Buerger's disease were evaluated on 126 admissions; 58 were new patients who were admitted for initial treatment, and 47 patients were experiencing a worsening of Buerger's disease and had a history of prior treatment. Forty-six new patients were admitted between 1985 and 1989, but only 12 new patients were admitted between 1990 and 1996 (9 +/ 3/ yr vs 2+/ 2/ yr, p = 0.0003). Between 1985 and 1989, 44 patients were admitted because of disease exacerbation, whereas only 24 such admissions occurred between 1990 and 1996 (9+/ 3/ yr vs 3 +/ yr, p = 0.0137). The number of admissions for atherosclerotic peripheral vascular disease did not change significantly in that period. Of the 105 patients, the majority (96%) were men; mean age at the time of disease onset was 36 +/ 8 years. The chief complaint on admission was gangrene/ulcer in 64%, rest pain in 13%, foot claudication in 6%, calf claudication in 6%, and other in 10%. CONCLUSION: The prevalence of Buerger's disease appears to be decreasing at our institution in Japan. Its clinical characteristics have not changed. A similar decrease in prevalence appears to have occurred in Western countries.

Adult↗
PubMed1998

Iontophoretic application of prostaglandin E1 for improvement in peripheral microcirculation.

OBJECTIVE: The pharmacological effects of iontophoretically applied prostaglandin E1 (PGE1) on the peripheral microcirculation were investigated. MATERIAL AND METHOD: PGE1 concentrations permeated through hairless mouse skin iontophoretically were measured by HPLC at hourly intervals. 19 patients with arteriosclerosis obliterans were given PGE1 (20 microg) iontophoretically on the dorsum of the foot. As a control, normal saline was applied iontophoretically on another day. The increase rate in cutaneous blood flow as measured by laser Doppler flux (LDF) level was investigated. 5 of these 19 patients received PGE1 (20 microg) solution intravenously on another day. The increase rate in cutaneous blood flow as measured by laser Doppler flux (LDF) level was compared between iontophoresis and intravenous drip infusion. RESULT: PGE1 was transported across hairless mouse skin with iontophoresis in a time-dependent manner, while it did not permeate by passive transport. The percent increase in LDF level was significantly higher in the PGE1 group than in the control group(32.7+/-20.2% vs. 10.3+/-15.5%, p.001). The percentual increase in LDF level was significantly higher with iontophoresis than with intravenous drip infusion (43.7+/-19.5% vs. 11.7+/-28.3%, p < 0.05). CONCLUSION: The results indicated that iontophoretically applied PGE1 was effective in improving the impaired microcirculation due to peripheral arterial occlusive disease. This technique may be useful in managing severely ischemic legs.

Alprostadil↗
PubMed1997

Up-regulation of integrin beta 3 expression by cyclic stretch in human umbilical endothelial cells.

The effect of uni-axial cyclic mechanical stretch on the expression of the adhesion protein integrin was investigated. Human umbilical endothelial cells (HUVECs) cultured on fibronectin coated silicon membranes were subjected to uni-axial cyclic stretch. The level of expression of integrin beta 3 mRNA was found to be increased and peaked at 4 hours in response to cyclic stretch using a semiquantitative RT-PCR method. The increased level of the integrin mRNA from stretched HUVECs remained higher than that from non-stretched controls. The amount of integrin beta 3 also increased and peaked at 12 hr. Immuno-fluorescent microscopy revealed that the amount of integrin beta 3 adhesions increased in stretched HUVECs compared with that in non-stretched HUVECs. These results suggest that uni-axial cyclic stretch up-regulates the expression of integrin beta 3. This increase in integrin beta 3 may enhance the adhesiveness to the substratum and contribute to the protection of HUVECs against being peeled off from the vessel wall.

Antigens, CD↗
PubMed1997

Subcutaneous tissue distribution of vancomycin from a fibrin glue/Dacron graft carrier.

We investigated the tissue distribution of vancomycin (VCM) incorporated in fibrin glue (FG) in a rat model. One VCM-loaded FG Dacron graft (VCM-FG, VCM 0.6 mg/ graft) was implanted in the subcutaneous tissue of the anterior abdominal wall of each rat. VCM was injected intravenously at an equal dose (0.6 mg/rat) after implantation of one control graft (without VCM-FG). After the implantation and the iv injection of an equal dose of VCM (0.6 mg/rat), the tissue distribution of VCM for up to 24 h was determined through analysis of the implanted VCM-FG grafts, which released VCM over a 24 h period. The area under the VCM concentration-time curve (AUC) of the tissue was 89.58 micrograms.h/g after the implantation of the VCM-FG graft, and 7.40 micrograms.h/g after the iv injection of VCM, respectively. The targeting index of the tissue, defined as the ratio of AUC after the implantation of the VCM-FG graft to that after VCM iv injection, was 12.11. None of the six VCM-FG Dacron grafts after implantation became infected following inoculation with S. aureus ATCC 25923 (0.1 mL 10(8) CFU/mL). These results suggest that this VCM-FG Dacron graft delivery may be useful in preventing local infection by enhancing the delivery of VCM to the local areas of the implanted site in rats.

Animals↗
PubMed1997

Measurement of spinal cord blood flow by an inhalation method and intraarterial injection of hydrogen gas.

PURPOSE: This study was performed to determine spinal cord blood flow using the H2 clearance method. METHODS: In 12 dogs we measured blood flow determined by hydrogen clearance techniques (BF) in both gray and white matter by spinal cord puncture, and compared the results with BF measured by a catheter inserted intrathecally to avoid spinal cord injury. We studied direct intraarterial and intravenous injection of hydrogen in addition to the inhalation method because hydrogen is an explosive gas. RESULTS: BF measured intrathecally with catheters adherent to either the ventral or the dorsal funiculus did not differ significantly from that of the gray matter. BF measured with a catheter inserted into the epidural space was about one fourth of the BF measured intrathecally. Values measured by the intraarterial injection method did not differ significantly from those obtained by the inhalation method. CONCLUSIONS: BF measured with a catheter inserted intrathecally reflects blood flow in the gray matter of the spinal cord. Using intraarterial injection of H2, BF was safety and accurately measured while avoiding the risk of explosion.

Administration, Inhalation↗
PubMed1997

Hemodynamic assessment of femoropopliteal venous reflux in patients with primary varicose veins.

PURPOSE: The aim of this study was to assess the anatomic distribution and extent of deep venous reflux in patients with primary varicose veins (PVVs) and to investigate its influence on venous hemodynamics. METHODS: Femoropopliteal venous reflux was examined using duplex color Doppler ultrasonography in 356 limbs with PVVs in 240 patients. Photoplethysmography (PPG) was performed using above-knee and below-knee tourniquets to determine the contributions of deep and superficial venous insufficiency. RESULTS: Of 356 limbs with PVVs, 61 (17.1%) had femoropopliteal venous reflux, 42 (11.8%) had superficial femoral venous reflux alone, and 57 (16.0%) had popliteal venous reflux alone. Femoropopliteal venous reflux was associated significantly with clinical symptoms and shortened the half venous refilling time measured by PPG, especially in the presence of incompetent perforating veins. These findings were obtained regardless of the presence of long saphenous vein reflux. CONCLUSIONS: Femoropopliteal venous reflux associated with PVVs plays an important role in the pathophysiologic mechanism of venous stasis and influences venous hemodynamics in the presence of incompetent perforating veins and short saphenous vein.

Adolescent↗
PubMed1997

Treatment for abdominal aortic aneurysm in a patient with hemophilia A: a case report and review of the literature.

A 77-year-old man with abdominal aortic aneurysm (AAA) was referred to our department. His AAA, which was 6 cm in diameter, was found incidentally with ultrasonography. On admission the diagnosis of hemophilia A was made for the first time in his life because activated partial thromboplastin time was decreased to 32.3% and factor VIII coagulant activity was 2.1% (normal range 40% to 140%). Recombinant factor VIII supplemental therapy was continued during surgery to maintain his factor VIII level within the normal range. His AAA was operated successfully with bifurcated graft replacement. No unusual bleeding complications occurred during his hospitalization. With proper preparation the patient with AAA and hemophilia A can safely undergo surgical treatment. Three other cases of AAA with hemophilia in the English literature were reviewed, and this is the oldest patient with hemophilia who underwent AAA surgery.

Aged↗
PubMed1997

Effect of walking distance on the change in ankle-brachial pressure index in patients with intermittent claudication.

OBJECTIVES: The ankle-brachial pressure index (ABPI) responses to different exercise intensities on a treadmill were evaluated to clarify the relationship between intermittent claudication and the haemodynamics in the leg. PATIENTS AND METHODS: Thirty patients with intermittent claudication (32 symptomatic legs) due to peripheral arterial occlusive disease were exercised on a treadmill to determine their pain-free walking distance, maximum walking distance (MWD) and recovery time. Each subject was exercised at 25% and 50% of the MWD to determine the effect of work intensity on the drop in ABPI, and the recovery time. RESULTS: In the claudicating legs, 25% of the MWD resulted in almost the same reduction in ABPI as 50% of the MWD, and the MWD. In contrast, the ABPI in the asymptomatic legs (13) was significantly decreased in proportion to the walking distance. The recovery time increased linearly in both the groups, as the walking distance increased. CONCLUSION: The recovery time of the ABPI correlated well with the intensity of workload, while the drop in ABPI did not.

Aged↗
PubMed1997

Late results of surgery for abdominal aortic aneurysm.

We investigated the long-term survival and quality of life (QOL) of patients after abdominal aortic aneurysm (AAA) repair, in a retrospective study of 216 patients who underwent surgery at Nagoya University Hospital between 1980 and 1992. There were 189 elective operations and 27 emergency operations (22 ruptures and 5 impending ruptures). Complete follow-up information was available for 91% of the 200 patients who survived the surgery. Excluding operative deaths there was no significant difference in survival between patients who underwent elective or emergency surgery. The survival for both groups was close to that of age- and sex-matched cohorts. A significantly shorter survival time was found in patients over 75 than in those who were 74 or less (p<0.05). Preoperative heart disease or hypertension did not affect long-term survival rate. At the time of the last follow-up, 70% of the patients were quite healthy, and approximately 20% continued to work. We conclude that long-term survival after AAA repair is as good as that of the general population, and that survivors enjoy a good quality of life. However, there may have been preoperative selection for low risk patients in this study.

Adult↗
PubMed1996

Urinary microalbumin as a marker for intermittent claudication.

OBJECTIVE: The urinary microalbumin concentration was analysed in patients with intermittent claudication in order to investigate its usefulness as a marker for intermittent claudication. MATERIALS AND METHODS: Urinary samples were collected prior to and following exercise in 15 patients with claudication. The patients walked on a treadmill as far as possible until they were stopped by pain. Urinary microalbumin concentration was measured by a latex agglutination system, and the result was considered abnormal when the concentration exceeded 10 mg/g creatinine. The ankle brachial pressure index (ABI) at rest and the time taken for the ankle pressure to return to the resting level following exercise (ABI recovery time) also were measured. RESULTS: In seven (47%) of the patients, the urinary microalbumin concentration was elevated to more than 10 mg/g creatinine following exercise, while in eight (53%) it remained normal. The ABI recovery time was significantly longer in the patients in whom the microalbumin concentration was elevated, compared to that in patients without an elevated concentration. The urinary microalbumin concentration following exercise was reduced significantly when the walking distance was decreased 50% or 15%. Following vascular bypass surgery, the elevation in urinary microalbumin concentration was reduced. CONCLUSIONS: The use of urinary microalbumin as a diagnostic marker for intermittent claudication is limited. However, in cases where the concentration is elevated, it can be used to follow the course of the disease.

Albuminuria↗