Biomedical subjects
Publications and source records attributed to S Shimokawa.
We report a case of adjacent intracranial tumours: malignant fibrous histiocytoma (MFH) and meningioma. Thallium-201 single-photon emission computed tomography demonstrated different thallium kinetics between the tumours (slow washout from the MFH and rapid clearance in the meningioma) and could be said to have been useful for preoperative histological estimation.
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PURPOSE: To assess the predictability and effectiveness of radial keratotomy in patients with myopic refractive error and unacceptable anisometropia after cataract surgery. SETTING: A prospective multicenter study. METHODS: This study comprised 40 eyes of 40 Japanese patients who had had cataract surgery. Radial keratotomy was performed, and the 6 month postoperative data were analyzed. RESULTS: Mean patient age was 71.0 years +/- 7.4 (SD) (range 51 to 84 years) and mean preoperative anisometropia -3.41 +/- 1.69 D (range -1.25 to -7.75 D). The surgery decreased mean anisometropia to -1.01 +/- 0.94 D (P < .000001, Wilcoxon signed-rank test), a mean reduction of 2.22 +/- 1.23 D (range 0.75 to 5.88 D). Postoperative anisometropia ranged from 0.81 to -3.13 D. The surgical effects were overestimated by the nomograms developed for the correction of naturally occurring myopia in the eyes of white patients. Multiple regression analysis revealed that optical zone size and number of incisions were significantly correlated with the amount of myopic correction, and the regression equation (R2 = 0.77) was expressed as follows: Effects = (-1.45 x optical zone size) + (0.24 x incision number) + 7.60. A new nomogram was derived based on this equation. CONCLUSIONS: Radial keratotomy was a safe and efficient procedure to treat myopic refractive error in pseudophakic eyes. Separate nomograms are necessary for white and Asian populations.
To assess the effect of tricuspid annuloplasty (TAP), the authors measured the size of the liver by using echography in the patients undergoing tricuspid annuloplasty. From April 1989 to August 1996, 18 patients underwent TAP. The authors measured preoperatively and postoperatively the hepatic index (HI) by echography, defined as follows: HI=L x D/BSA (L: the top-to-bottom length of the left hepatic lobe; D: the front-to-back length of the left hepatic lobe; BSA: body surface area). They also calculated the reducing rate (RR) of HI. The mean HI decreased after TAP; preoperative HI: 39.7+/-11.8 vs postoperative HI: 33.8+/-10.5 (p=0.0069). The RR of the patients with postoperatively residual tricuspid regurgitation (TR) over 2 degrees (n=4) was significantly lower than that of the other patients (n=14): -11.0+/-6.0% vs 20.2+/-3.2% (p=0.0003). They conclude that the use of echography to measure the HI is a good method of assessing congestion after TAP.
Visualization of copper-induced hepatitis (CuH) in LEC rats was performed by using an MRI apparatus equipped with a magnet producing a high magnetic field of 7.05 T. When three groups of LEC rats (6-16 [pre-hepatitis], 15-26 [acute hepatitis] and 40-77 [chronic hepatitis] weeks old) were examined by MRI under T2-weighted imaging conditions which are suitable for the diagnosis of human hepatitis, hypointense MR images of the livers were, as a whole, obtained in all groups, suggesting that these conditions were not adequate for imaging of CuH of LEC rats. The shortening of the T1 and T2 relaxation times of livers due to an excess amount of paramagnetic irons under the high magnetic field was responsible for the lowering of MR signal intensities of the livers, especially those of 15 to 26-week old rats showing acute hepatitis. However, theoretical calculation of the MR signal intensities using the T1 and T2 relaxation times of the livers indicated that their imaging might be possible under proton density-weighted conditions even with a high magnetic field. Experimental results showed that hepatic injury was visualized as hyperintense regions in the MR image of the liver in the acute-phase rat.
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BACKGROUND AND AIM OF THE STUDY: The long-term clinical experience of patients receiving Omnicarbon heart valve prostheses between January 1985 and December 1996 was investigated. METHODS: In total, 473 patients (255 males, 218 females; mean age 57.5 +/- 10.1 years (range: 20n-73 years) received 523 prostheses. These included 253 mitral (MVR), 170 atrial (AVR) and 50 double (DVR) valve replacements. RESULTS: The 30-day mortality rate was 4.7% (n = 22); in addition eight patients died more than 30 days after surgery, but during the same hospital stay. Mean follow up was 3.9 years (maximum 11 years and 7 months). Cumulative follow up was 1,750.1 patient-years (pt-yr); follow up was 97.5% complete. Among 39 late deaths, 20 were valve-related (seven cerebral infarction, seven cerebral bleeding, six endocarditis) and four cardiac-related. The overall five-year cumulative survival rate (excluding early mortality) was 90.2 +/- 11.7% (MVR 88.0 +/- 2.5%, AVR 93.1 +/- 2.3%, DVR 93.7 +/- 4.8%). At 10 years, the overall survival rate was 76.4 +/- 7.7%. Valve-related complications included thromboembolism (n = 13, 0.7%/pt-yr), anticoagulation-related hemorrhage (n = 12, 0.7%/pt-yr) and endocarditis (n = 7, 0.4%/pt-yr). Neither mechanical failure nor clinical hemolysis was observed. The overall valve-related event-free rate after five years was 89.3 +/- 2.0% (MVR 89.8 +/- 2.4%, AVR 93.5 +/- 2.6%, DVR 89.4 +/- 5.7%) and after 10 years it was 87.6 +/- 2.6% (MVR 85.4 +/- 3.7%, AVR 93.5 +/- 2.6%, DVR 82.5 +/-10.1%). CONCLUSIONS: These long-term results with the Omnicarbon valve are excellent; especially satisfactory results were achieved in terms of the low rate of thromboembolic complication.
We report the case of a 74-year-old man found to have an extensive intramural hematoma (IMH) in the infrarenal abdominal aorta during a follow-up imaging study performed after repair of a DeBakey type II aortic dissection with an aortic arch true aneurysm. Enhanced computed tomographic scan and angiography revealed an extensive IMH and multiple penetrating atherosclerotic ulcers in the abdominal aorta. The patient underwent a successful replacement of the affected abdominal aorta using a collagen-impregnated woven Dacron graft. Atheromatous ulcers are known to occur frequently in patients with advanced atherosclerosis. Hence, the elderly hypertensive patient, being at high risk of developing a variety of aortic disorders, requires careful follow-up imaging studies to assess the aorta on a regular basis.
We report herein the case of a 66-year-old man who underwent resection and reconstruction of the chest wall due to the presence of a malignant melanoma without a detectable primary lesion. The patient was discharged in good condition after receiving chemotherapy but eventually died of multiple bone metastases 2 years after surgery. Throughout the postoperative course, there were no specific symptoms or findings suggesting the presence of a primary lesion. It was considered likely that the primary tumor was resolved by spontaneous regression after chest wall metastasis had been established.
A 63-year-old man and a 49-year-old man who underwent PTMC eight years before were admitted in our hospital because of regurgitation and restenosis of the mitral valve. Both of them had ulcer like lesion on the anterior leaflet near the commissure of the mitral valve. These changes were made by PTMC and likely caused thrombosis. Long-term follow up data of PTMC is essential to chose the correct operative method for treating mitral stenosis.
A 68-year-old man with an infrarenal mycotic aneurysm underwent successful in-situ graft reconstruction using a woven Dacron graft. A tissue culture taken from the excised aortic wall revealed Staphylococcus epidermidis, and histological study subsequently showed penetrating atherosclerotic ulcers (PAU) involving all layers of the aortic wall and marked neutrophilic infiltration with abscess formation inside the ulcer. Atherosclerotic aortic lesions such as PAU are considered susceptible to bacterial infection, which may lead to the formation of an aneurysm after destruction of the vessel wall. Hence, elderly hypertensive patients, being at high risk for such aortic pathology, require careful studies performed to assess the aorta. The usefulness of computed tomographic (CT) scans to determine the presence of PAU or surrounding inflammation should be borne in mind even when a small mycotic aneurysm exists.
The presence of atherosclerotic coronary artery aneurysms is not always considered to be an operative indication. However, progressively expanded coronary artery aneurysms may have the potential for complications such as rupture or embolism. We present a case of successful repair of a coronary artery aneurysm located above the first septal perforator in the left anterior descending coronary artery using a saphenous vein patch and simultaneous construction of a right gastroepiploic artery graft to the occluded right coronary artery. Follow-up angiography at 6 months after operation revealed complete disappearance of the aneurysm with no luminal stenosis and a preserved large septal branch. The right gastroepiploic artery graft was also found to be widely patent.
Total eventration of the hemidiaphragm is a rare condition in adults. We report a 75-year-old woman with large eventration of the right diaphragm who required an emergency plication because of acute progressive respiratory distress. The symptom disappeared immediately after operation. Even in asymptomatic elderly patients with eventration, close follow-up is recommended.
OBJECTIVE: This study was designed to clarify the optimal treatment mode of patients with intramural hematoma (IMH) of the thoracic aorta. METHODS: From 1992 through 1997, 51 patients underwent surgical repair or medical treatment of IMH of the thoracic aorta. There were 36 male and 15 female patients, aged between 49 and 79 years with a mean of 67 years. The ascending aorta and/or aortic arch was involved in 18 patients (group I), whereas the descending thoracic aorta was affected in 33 (group II). The presence of intimal disruption in IMH was confirmed in 10 of group I and 13 of group II patients. RESULTS: For group I patients 13 required aortic arch repairs and the remaining 5 underwent conservative therapy including anti-hypertensive medication. Primary indications for immediate surgery were: cardiac tamponade in 5 patients, aortic dissection superimposed on IMH in 2, and persistent pain with an aortic arch aneurysm in 1, respectively. Early elective operations were done for enlarged ulcer in 3 patients and aneurysmal dilatation in 2 of which 1 had a coexisting aortic arch aneurysm. The 2-year survival rate after diagnosis was 94% with an operation-free rate of 25%. Nine of the group II patients experienced surgical intervention of which 8 had intimal disruption, 4 patients received urgent replacement of the descending thoracic aorta for massive pleural effusion and 1 had the aortic arch replaced for a coexisting aneurysm with persistent pain. All other patients underwent conservative treatment and 4 of them had to be shifted to early surgery during the initial hospitalization because of an enlarged ulcer. The 5-year survival rate in group II patients was 63% with an operation-free survival rate of 66%. CONCLUSIONS: On the basis of our experience early operation is recommended for almost all patients with ascending aortic IMH, and medical therapy for those with descending aortic involvement unless complication developed. However, the presence of intimal disruption may require early surgical treatment even in the patients with descending thoracic IMH.
A nuclear magnetic resonance (NMR) spectrometer equipped with a magnet producing a high and extremely uniform magnetic field (7.05 T) was combined with a strong field gradient coil (3.5 mT/cm) and applied to MR microimaging of the mouse brain to visualize its topographical structure. Since the proton-density-weighted condition (long repetition time (TR) and short echo time (TE); TR/TE = 3,000 ms/10.4 ms) was found to be the most suitable for imaging the mouse brain, mid-sagittal and coronal sections in 1-mm- or 0.3-mm-thick slices were imaged according to the multislice spin echo sequence with 2 or 8 acquisitions, a 2 kHz pulse width and a 256 x 256 data matrix. As expected, the resolution of MR microimaging was comparable to that of the histological sections. The white matter especially, could be distinguished from the gray matter in some regions of the brain. Coronal sections of the brain also showed that the hippocampal CA1-CA3 regions were distinguishable from the other regions. The results suggested that the present MR microimaging technique might be a useful tool for the study of topological anatomy and submicroscopic research using brains of small laboratory animals.
Fasudil hydrochloride is a new type of intracellular calcium antagonist, different from the calcium entry blockers that are commonly employed for clinical use. Since September 1995, the combination of fasudil hydrochloride and ozagrel sodium, an inhibitor of thromboxane A2 synthesis, has been used to treat 60 patients at risk of cerebral vasospasm after aneurysmal subarachnoid hemorrhage. The effectiveness of this combination therapy was investigated by comparison with the outcome of 57 patients previously treated with only ozagrel sodium. The combination therapy was significantly more effective (p < 0.01) in reducing the incidence of low density areas on computed tomography scans, and reduced, but not significantly, the occurrence of symptomatic vasospasm. The combination therapy of fasudil hydrochloride and ozagrel sodium has superior effectiveness over only ozagrel sodium in treating patients at risk of vasospasm after aneurysmal subarachnoid hemorrhage.
77 cases of acute type A dissection underwent emergency operation during 5 years were studied. There were 37 men and 40 women, and 58 cases in type I, 19 cases in type II on DeBakey type. The grafting for the aorta including the tear was basically performed under selective brain perfusion and deep hypothermic circulatory arrest. The overall hospital mortality rate was 24.7%. However, it was 14% after using GRF glue. The overall actuarial survival rate for 58 patients who survived operation was 87% at 5 years after surgery. Late remnant false lumen-related complications were recognized in four patients (6.9%). For two of them, subsequent operations were performed. Another two patients died of rupture of remnant false lumen during observation. Aortic valve regurgitation was recognized preoperatively in 13 patients. None of them required subsequent operation in late phase. Results and countermeasure for late remnant false lumen-related and aortic valve-related complications were investigated.
BACKGROUND AND AIMS OF THE STUDY: This study reports the clinicopathologic characteristics of congenital bicuspid aortic valves necessitating surgical intervention. METHODS: Among 374 aortic valve procedures during the past 15 years, 63 cases of bicuspid aortic valve were encountered. Patients included 45 males and 18 females; mean age was 53 years (range: 14 to 76 years). RESULTS: Thirty-two patients demonstrated aortic stenosis (AS), 27 aortic regurgitation (AR), and four had both conditions. Patients with AR were significantly younger than those with AS (45 +/- 13 versus 60 +/- 11 years; p < 0.01). Histologic study of the excised valve disclosed severe myxoid degeneration in 16 of 27 patients with AR. These patients underwent surgery at a younger age than the other 11 with calcification and endocarditis (40 +/- 13 versus 52 +/- 10 years; p = 0.01). Based on the macroscopic appearance, the lesions were divided into those with (n = 38) and without (n = 25) raphe. Twenty-one patients (55%) in the former group demonstrated AR, whereas 19 (76%) in the latter group demonstrated AS. Patients with raphe were significantly younger at the time of surgery than those without raphe (50 +/- 15 versus 57 +/- 11 years; p = 0.02). As a complication, ascending aortic aneurysm was observed in six patients. CONCLUSIONS: In a bicuspid aortic valve, calcification with stenosis commonly occurs in most older patients. However, in some young adult patients with raphe, AR may result from myxoid degeneration. The presence of raphe in the bicuspid valve appears to have a significant influence on valve hemodynamics.