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Biomedical subjects

T Ohki

Publications and source records attributed to T Ohki.

At least 91 records · Page 5Linked to original sources
PubMed1997

Chronic intraaneurysmal pressure measurement: an experimental method for evaluating the effectiveness of endovascular aortic aneurysm exclusion.

PURPOSE: To evaluate and compare the intraaneurysmal pressure (IAP) after exclusion using two different endovascular grafts. METHODS: Eight mongrel dogs had a 3 x 3 cm polytetrafluoroethylene (PTFE) aneurysm sewn as an interposition graft of the infrarenal aorta. A pressure transducer implanted into the aneurysm wall permitted continuous electronic IAP monitoring. Four aneurysms were excluded with a transluminally placed endovascular graft made of a PTFE graft and two Palmaz stents (PTFE-EG), three were excluded with a tantalum-Dacron endovascular graft (TD-EG), and one was surgically treated with a standard PTFE graft (PTFE-Surg). The dogs were observed for 18 to 50 days (mean, 37.5 days) and were evaluated after surgery with duplex and spiral computed tomographic scans. RESULTS: All grafts successfully excluded the aneurysms without perigraft channels or leaks as documented by arteriogram and duplex and computed tomographic scans. The mean IAPs after repair with all PTFE-EGs were significantly lower (p < 0.001) than the mean systemic pressures. In addition, the mean IAP reduction was significantly greater (p < 0.005) in the PTFE-EG group than in the TD-EG group. CONCLUSIONS: Aneurysm exclusion with PTFE-EG significantly lowered IAP, did so significantly better than the TD-EG, and approached the IAP reduction obtained by standard repair. Such pressure reduction is necessary for effective protection against aneurysm rupture.

Animals↗
PubMed1997

Severe myoclonic epilepsy in infancy: evolution of seizures.

Changes in seizure type of severe myoclonic epilepsy (SME) in infancy were reviewed retrospectively in 14 patients (11 males and 3 females) who were followed-up to the age of 7 years or more. The observation period ranged from 5 to 16 years with a mean of 10 years. During the follow-up, three or four types of seizures were seen per patient, but the pattern of appearance and disappearance of each seizure type varied considerably among the patients. Tonic-clonic convulsion, either generalized or unilateral, was seen most consistently through the entire course, and it continued to the end of follow-up in 11 patients (79%). On the contrary, myoclonic seizure, complex partial seizure, and atypical absence often disappeared and reappeared repeatedly during the course. In SME, seizure symptoms varied widely among patients in comparison with other neurological symptoms, and the most consistent core seizure type was tonic-clonic convulsions.

Child↗
PubMed1997

Autonomic nervous system activity in essential hypertension: a comparison between dippers and non-dippers.

The present study was undertaken to investigate the changes in autonomic nervous system activity in essential hypertension. Fourteen normotensive controls and 33 age-matched untreated hypertensive subjects, diagnosed by ambulatory blood pressure (ABP) measurement (24-h systolic ABP value over 140 mm Hg or 24-h diastolic ABP over 90 mm Hg, or both) were recruited. ABP and 24-h electrocardiogram were monitored simultaneously. Power spectral analysis of the R-R interval was performed by a fast Fourier transformation method and the powers of low frequency (LF; 0.04 to 0.15 Hz) and high frequency (HF; 0.15 to 0.4 Hz) components were obtained. Hypertensive subjects were divided into 'dippers', whose night-time systolic ABP fell by more than 10% of their daytime ABP, and 'non-dippers' in whom this phenomenon was absent. In hypertensive subjects, electrocardiogram monitoring and power spectral analysis were also performed for 5 min before and during 90 degrees tilt. There were no significant differences in the 24-h mean LF/HF power ratio, LF power or HF power between normotensive and hypertensive subjects. A significant negative correlation between the night-time systolic ABP level and the 24-h LF/HF power ratio was found (r= -0.36, P < 0.05) in the hypertensive subjects. A significant positive correlation was found between the 24-h LF/HF power ratio and the percentage nocturnal reduction of the daytime systolic ABP in hypertensive subjects (r = +0.40, P < 0.01). The 24-h LF/HF power ratio was significantly lower in non-dippers than in dippers (2.09 +/- 1.06 vs 3.24 +/- 0.97, P < 0.01). The mean daytime LF/HF power ratio was significantly lower in non-dippers than in dippers (2.50 +/- 1.43 vs 4.08 +/- 1.27, P < 0.01). The night-time LF/HF power ratio was not significantly different between the two groups. The LF/HF power ratio increased significantly in dippers (from 1.32 +/- 1.95 to 4.65 +/- 1.54, P < 0.001) during 90 degrees tilt, but there was no significant change in the LF/HF power ratio in non-dippers during tilt (from 1.13 +/- 0.28 to 1.36 +/- 0.78, NS). The 24-h LF/HF power ratio decreased according as the night-time systolic BP elevated in hypertensive subjects. During ambulatory monitoring, the non-dippers showed a significantly lower LF/HF power ratio than the dippers. The LF/HF power ratio increased significantly in dippers, but not in non-dippers during tilting. These results suggest that impaired cardiovascular reflexes might contribute to the decreased sympathovagal balance in non-dipper type hypertension.

Autonomic Nervous System↗
PubMed1997

Should vascular surgeons perform endovascular procedures and how can they acquire the skills to do so?

Endovascular treatment techniques have already replaced some vascular operations. The likelihood is that new endovascular techniques involving stents and stented grafts will replace additional vascular operations. All of these treatments involve the use of catheter-guidewire, balloon, and imaging modalities, particularly digital fluoroscopy. These modalities have already and will increasingly help to improve and simplify standard vascular operations such as thromboembolectomy, infrainguinal bypasses, and management of aneurysms and arteriovenous fistulas. Accordingly, vascular surgeons must become familiar with and use these endovascular methods and techniques. This can be accomplished in a variety of ways, including working as part of a multidisciplinary vascular treatment group in which various specialists collaborate to provide the best, most cost-effective care to vascular disease patients.

Angioplasty, Balloon↗
PubMed1997

Varying strategies and devices for endovascular repair of abdominal aortic aneurysms.

The endovascular repair of abdominal aortic aneurysms has been investigated in a clinical setting since 1991. Although initially the procedure was performed using surgeon-made devices, it did not take long for the medical industry to realize the potential of this procedure. There are six commercially made devices, which are unique, each with their own strengths and weaknesses. This article describes the principal endovascular graft types that are currently under investigation as well as the strategies for their use. In addition, the inclusion criteria for endovascular repair of abdominal aortic aneurysms are discussed.

Aortic Aneurysm, Abdominal↗
PubMed1997

Endovascular approaches for traumatic arterial lesions.

Vascular injuries caused by blunt or penetrating trauma can be challenging to diagnose and treat, particularly when they involve central vessels. Endovascular treatment for vascular trauma includes the placement of embolization coils and intravascular stents and the employment of stented grafts. The use of stented grafts appears to be associated with decreased blood loss, a less invasive insertion procedure, reduced requirements for anesthesia, and a limited need for an extensive dissection in a traumatized field. These advantages are especially important in patients with central arteriovenous fistulas or false aneurysms, particularly those who are critically ill from other coexisting injuries or medical comorbidities. In these circumstances, the use of stented grafts already appears justified to treat traumatic central arterial lesions. Endovascular grafts are important tools for the treatment of vascular trauma, and they should be included in the armamentarium of the vascular surgeon.

Angiography↗
PubMed1997

Endovascular grafting for aortoiliac occlusive disease.

Aortoiliac occlusive disease is a significant cause of lower extremity ischemic symptoms. Over the past two decades, most patients have been treated with a variety of surgical procedures, including aortofemoral and extra-anatomic bypasses. Most recently, percutaneous balloon angioplasty and stents have been successfully used for the treatment of limited iliac lesions. New endovascular grafts that combine vascular grafts with stents in a device with new characteristics may allow the successful treatment of patients with extensive aortoiliac occlusive disease in a less invasive fashion. In our early experience, the endovascular grafts were constructed with Palmaz balloon-expandable stents and standard polytetrafluoroethylene (PTFE) grafts. The 18-month primary and secondary patency rates were 89% and 100%, respectively, with a limb salvage rate of 94%. Endovascular grafts can be successfully used to treat patients with extensive aortoiliac occlusive disease, with excellent early results. Long-term results and further graft improvements will define their role in the treatment of patients with aortoiliac occlusive disease.

Aorta, Abdominal↗
PubMed1996

Endovascular aortounifemoral grafts and femorofemoral bypass for bilateral limb-threatening ischemia.

PURPOSE: Although axillobifemoral bypass procedures have a lower mortality rate than aortobifemoral bypass procedures, they are limited by decreased patency, moderate hemodynamic improvement, and the need for general anesthesia. This report describes an alternative approach to bilateral aortoiliac occlusive disease using unilateral endovascular aortofemoral bypass procedures in combination with standard femorofemoral reconstructions. METHODS: Seven patients who had bilateral critical ischemia and tissue necrosis in association with severe comorbid medical illnesses underwent implantation of unilateral aortofemoral endovascular grafts, which were inserted into predilated, recanalized iliac arteries. The proximal end of the endovascular graft was fixed to the distal aorta or common iliac artery with a Palmaz stent. The distal end of the graft was suture-anastomosed to the ipsilateral patent outflow vessel, and a femorofemoral bypass procedure was then performed. RESULTS: All endovascular grafts were successfully inserted through five occluded and two diffusely stenotic iliac arteries under either local (1), epidural (5), or general anesthesia (1). The mean thigh pulse volume recording amplitudes increased from 9 +/- 3 mm to 30 +/- 7 mm and from 6 +/- 2 mm to 26 +/- 4 mm ipsilateral and contralateral to the aortofemoral graft insertion, respectively. In all cases the symptoms completely resolved. Procedural complications were limited to one local wound hematoma. No graft thromboses occurred during follow-up to 28 months (mean, 17 months). CONCLUSIONS: Endovascular iliac grafts in combination with standard femorofemoral bypass grafts may be an effective alternative to axillobifemoral bypass in high-risk patients who have diffuse aortoiliac occlusive disease, particularly when bilateral axillary-subclavian disease is present.

Aged↗
PubMed1996

Cryptogenic localization-related epilepsy of neonatal onset.

We report three patients with localization-related epilepsy of neonatal onset. They exhibited favourable psychomotor development and had no cerebral lesions on neuroimaging studies despite the presence of intractable partial seizures of neonatal onset. Although rare, some cases of epilepsy of neonatal onset may be cryptogenic, i.e. they belong to neither the symptomatic nor the idiopathic group.

Blood Glucose↗
PubMed1996

Changes in histologic grade and argyrophilic nucleolar organizer regions during progression of prostate cancer.

To determine the changes in histologic features during the course of prostate cancer under long-term endocrine therapy, histologic grade and argyrophilic nucleolar organizer regions (AgNORs) were examined in specimens before treatment, at relapse, and at cancer death. A total of 29 patients who had received therapy and died of prostate cancer were evaluated. Among the 29 cases, biopsy tissues before treatment (25 cases) and during progression from endocrine therapy (10 cases) were compared with autopsy specimens. Histologic grade was determined by the method of Gleason, and the number of AgNORs in cancer cells was counted. Survival of the patients was compared with the histologic features. There was a tendency for a higher grade of cancer during the clinical course. Moreover, a statistically significant increase in the number of AgNORs was observed from pretreatment biopsy to autopsy. Upon comparison of metastatic sites with local cancer at autopsy, no significant difference was noticed in terms of histologic grade or AgNOR count. Although there was no correlation between the number of AgNORs and survival after initial treatment, an inverse relationship was demonstrated between the number of AgNORs and survival in patients with systemic progression after endocrine therapy. In conclusion, prostate cancer shows an increase of malignant potential, as assessed by histologic grade and the number of AgNORs. Patients with cancer of high proliferative ability showing high grade and greater numbers of AgNORs have poorer prognosis from progression.

Biopsy↗
PubMed1996

[Initial outcome of coronary intervention in elderly patients].

The effect of age on the early results of coronary intervention was examined retrospectively using the initial success rate of coronary angioplasty in 60 patients older than 70 years. Patients were selected from those who underwent coronary angioplasty at the Saiseikai Utsunomiya Hospital from January 1992 to December 1994. There were 267 patients with 350 lesions, 223 men and 44 women, aged from 31 to 79 years (mean age 61.4 +/- 9.8 years). The elderly group consisted of 60 patients (mean age 73.5 +/- 3.0 years) and the control group was 207 patients less than 70 years (mean age 57.9 +/- 8.2 years). Successful coronary dilatation was defined as > 20% reduction of stenosis with residual stenosis < 50%. Body mass index, presence of hypertension or diabetes mellitus and the ratio of smokers were not significantly different between the two groups. The elderly group included more women and patients with hyperlipidemia. Both groups had similar baseline extent of coronary artery disease, distribution of coronary artery stenosis type and left ventricular ejection fraction. The initial success rate for all patients was 93.4%. There was no significant difference in the initial success rate between the elderly and control groups (98.8% and 91.9%, respectively). There was no significant difference in major complication rate between the two groups (6.3% and 11.5%). Multivariate logistic regression analysis showed that only the type of coronary artery stenosis was significantly associated with initial success rate (p < 0.01). These results suggest that coronary intervention can be successfully performed with a low incidence of major complication in elderly patients.

Adult↗
PubMed1995

Secondary exposure of medical staff to sarin vapor in the emergency room.

OBJECTIVE: To clarify the risk of secondary exposure of medical staff to sarin vapor in the emergency room, and to warn emergency room staffs of the hazard. DESIGN: Retrospective observational survey. SETTING: Emergency department of a university hospital in a metropolitan area of Japan. PARTICIPANTS: Fifteen doctors treating victims of a terrorist attack with sarin in the Tokyo subways on the day of the attack. MEASUREMENTS AND RESULTS: Of the 15 doctors who worked in the emergency room treating the victims, 13 became simultaneously aware of symptoms during the resuscitation of two victims who were exposed to sarin. Among 11 doctors (73%) who complained of dim vision, the pupils were severely miotic (<2 mm) in 8 (73%). Other symptoms included rhinorrhea in eight (53%), dyspnea or tightness of the chest in four (27%), and cough in two (13%). Atropine sulfate was given to six, and pralidoxime was given to one of these six doctors. To decontaminate the emergency room of sarin vapor, ventilation was facilitated and all belongings of the patients were sealed up. None of the doctors noticed worsening of their symptoms thereafter. CONCLUSIONS: Careful attention to the risks of secondary exposure to toxic gas in the emergency room and prompt decontamination if such exposure should occur are necessary in the case of large-scale disasters caused by sarin.

Adult↗
PubMed1995

Do ictal, clinical, and electroencephalographic features predict outcome in West syndrome?

Ictal electroencephalographic/video recordings of 42 patients with West syndrome (WS) were reviewed to define the relation between ictal, clinical, and EEG features and etiology or prognosis. The duration and type of spasms, the number of spasms per cluster, and the interval between spasms did not correlate with the etiology or the short-term prognosis. However, eye deviation, asymmetric spasms, and partial seizures concomitant with spasms were observed only in symptomatic WS patients with poor outcome. In particular, all 8 patients with concurrent partial seizures had severe psychomotor retardation. The ictal EEG characteristics did not correlate with etiology and prognosis. There was no significant difference between the patients with persistence or reappearance of hypsarrhythmia and the patients without interspasm hypsarrhythmia.

Electroencephalography↗
PubMed1995

Antiandrogen withdrawal syndrome in prostate cancer after treatment with steroidal antiandrogen chlormadinone acetate.

OBJECTIVES: A case report is presented of 2 patients whose levels of serum prostate-specific antigen (PSA) improved after the withdrawal of a steroidal antiandrogen. METHODS: Two cases with prostate cancer had been treated with surgical castration and the steroidal antiandrogen chlormadinone acetate (CMA), and, on disease progression, the administration of CMA was terminated. RESULTS: Following withdrawal of CMA, a fall in PSA levels and remarkable clinical improvement were observed in both cases. One patient revealed a decrease and the other an increase in serum prostate acid phosphatase after the discontinuation of CMA. Serum levels of testosterone, prolactin, dehydroepiandrosterone, dehydroepiandrosterone sulfate, and androstenedione were not significantly elevated after CMA withdrawal. CONCLUSIONS: Withdrawal of the steroidal antiandrogen CMA resulted in a decline in PSA levels and clinical improvement in prostate cancer patients with disease progression. Changes in testosterone, prolactin, or adrenal androgens were not a cause of the antiandrogen withdrawal syndrome.

Aged↗