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Biomedical subjects

T Hirai

Publications and source records attributed to T Hirai.

At least 289 records · Page 16Linked to original sources
PubMed1995

Improved 20-hour canine lung preservation with a new solution--ET-Kyoto solution.

We developed a new solution, ET-Kyoto (ET-K) solution, and compared its efficacy in 20 h lung preservation with that of Euro-Collins (EC) solution in a canine left lung transplantation model. The lungs were flushed with ET-K solution (ET-K group, n = 5), with EC solution plus prostaglandin E1 (PGE1) pretreatment (EC + PGE1 group, n = 6) or with EC solution (EC group, n = 6), and were stored at 4 degrees C for 20 h. The function of left lung grafts was assessed 40, 70, and 130 min after transplantation. The arterial pressure of oxygen (PaO2) in the ET-K group was significantly greater than in the EC + PGE1 group (p < 0.05 or p < 0.01) and in the EC group (p < 0.01). The peak inspiratory pressure and wet to dry weight ratio in the ET-K group were significantly lower than in the EC + PGE1 group and in the EC group (p < 0.05 or p < 0.01). Pulmonary vascular resistance in the ET-K group 130 min after reperfusion was significantly lower than in the EC group (p < 0.05). All the transplanted lungs in the EC + PGE1 group and the EC group showed histological evidence of pulmonary edema, whereas all in the ET-K group showed no signs of edema. We concluded that ET-K solution is superior to EC solution with or without PGE1 pretreatment in 20 h canine lung preservation.

Animals↗
PubMed1995

Intravascular hyperthermia: experimental study of transcatheter treatment.

RATIONALE AND OBJECTIVES: External hyperthermia has frequently been used to treat superficial malignant tumors. We postulated that transarterial internal hyperthermia may be effective for deeply located hypervascular tumors. We performed intravascular hyperthermia (IVH) for malignant hypervascular tumors that were transplanted into animals and evaluated the resulting histologic changes and antitumoral effects. METHODS: We designed a special catheter to heat the injected saline. Sixteen rabbits with hypervascular VX2 tumors ranging from 2 to 2.5 cm in diameter in their left hindlimb muscles served as subjects. IVH was performed via the left femoral artery (temperature = 50 degrees C) in 11 rabbits. Two sessions of IVH were performed during 1 week. Two weeks after the two sessions of IVH, the rabbits were sacrificed and their tumors and feeding arteries were resected. Five control rabbits had 37 degrees C saline infused using the same technique. RESULTS: The temperature in the central zone of the tumor increased markedly to 42.3 +/- 0.5 degrees C (mean +/- standard deviation), compared with 40.3 +/- 0.4 degrees C and 39.2 +/- 0.5 degrees C in the peripheral zones of the tumor and the surrounding tissue, respectively. Tumor sizes were calculated on angiograms as having decreased by 63 +/- 35% of their initial sizes during the 2 weeks after the two IVH sessions. However, tumor sizes increased to 171 +/- 41% in the control group (p < .01). Necrosis in the peripheral zones of the tumors in the IVH group was more severe than that in the control group (p < .05). Necrosis in the central zones of the tumors in the IVH group was slightly more severe. The surrounding tissue was not damaged. Although the femoral artery was not severely damaged, there was severe damage to the feeding arteries. CONCLUSION: IVH reduced the size of hypervascular tumors in our rabbits. The antitumoral effects are attributed to direct damage of the tumor vessels and to the effect of heat on the tumor cells.

Adenocarcinoma↗
PubMed1995

Ultrasonic observation of the nail matrix.

BACKGROUND: The authors made use of echograms for the observation of the nail matrix. OBJECTIVE: To inspect the nail matrix and identify what causes nail plate deformities. METHODS: A 30-MHz frequency high-resolution B-mode was applied to normal and damaged nails. RESULTS: Clear shadows of underlying nail plates were observed beneath the proximal nail fold. Some cases with nail plate deformities showed damaged sub-proximal fold nail plates, which would indicate nail matrix deformities. CONCLUSION: The echograms had diagnostic value to nail plate deformities. If a normal echogram is obtained at the proximal nail fold, the nail bed will be the place at which the nail deformities occur. If the echogram indicates any sub-proximal fold nail plate changes, the damaged nail matrix may be attributable to the nail deformities. Echograms also gave clear echoic shadows of subungual tumors. That contributed to identifying the infiltrating border of subungual malignant melanomas around the nail matrix noninvasively.

Fingers↗
PubMed1995

Hemifacial spasm: three-dimensional MR images in the evaluation of neurovascular compression.

PURPOSE: To assess the diagnostic accuracy of three-dimensional (3D) magnetic resonance (MR) images in the preoperative evaluation of hemifacial spasm. MATERIALS AND METHODS: In 27 patients with surgically confirmed hemifacial spasm, the axial source images from 3D time-of-flight MR angiography were evaluated for 27 symptomatic sides and 26 asymptomatic sides by three observers in a blinded manner for neurovascular compression and identification of compressive vessels. RESULTS: Sensitivity was 95% and specificity was 77%. Vascular compression on the symptomatic sides could be identified retrospectively in all 27 patients. On the asymptomatic sides, vascular compression could be excluded retrospectively in all but one patient. In the blinded study, as the mean value of three observers, the vertebral artery and posterior inferior cerebellar artery could be identified correctly in seven and 7.7 of seven and nine patients, respectively, whereas the compressive anterior inferior cerebellar artery was identified correctly in 7.7 of 16 patients. CONCLUSION: Three-dimensional MR images have a high diagnostic accuracy and are useful in the preoperative evaluation of hemifacial spasm.

Adult↗
PubMed1995

Differential sympathetic nerve responses to nitric oxide synthase inhibition in anesthetized rats.

Recent studies have suggested that the interaction between the sympathetic nervous system and nitric oxide (NO) or nitrosyl factors may be an important means by which arterial blood pressure is regulated. We investigated whether NO synthase (NOS) inhibition modulates basal sympathetic nerve discharge (SND) in baroreceptor-innervated and -denervated, chloralose-anesthetized Sprague-Dawley rats. We recorded mean arterial pressure (MAP), renal SND, and lumbar SND before and after administration of the NOS inhibitor, NG-nitro-L-arginine methyl ester (L-NAME, 20 mg/kg iv). Two minutes after L-NAME administration in baroreceptor-innervated rats, MAP increased (+23 +/- 3 mmHg), whereas renal (-45 +/- 6%, n = 7) and lumbar (-35 +/- 2%, n = 6) SND significantly decreased from control levels. These changes persisted for up to 20 min after L-NAME administration. In baroreceptor-denervated rats, L-NAME increased MAP (+40 +/- 6 mmHg) and decreased lumbar SND (n = 7) (-37 +/- 10% from control at 20 min post-L-NAME). In contrast, renal SND progressively increased (+33 +/- 8% at 20 min post-L-NAME) from control after L-NAME administration in baroreceptor-denervated rats (n = 7). These results demonstrate that NOS inhibition can produce nonuniform changes in SND in baroreceptor-denervated rats and suggest that endogenous nitrosyl factors provide tonic excitation to lumbar SND, whereas they provide a tonic restraint to renal SND.

Animals↗
PubMed1995

Sympathetic nerve responses to hyperthermia in the anesthetized rat.

The aim of the present study was to characterize the sympathetic nerve responses to hyperthermia in chloralose-anesthetized rats. Discharges were recorded from the renal, lumbar, and splanchnic sympathetic nerves. Mean arterial pressure, heart rate, and sympathetic nerve discharge (SND) were recorded continuously during progressive increases in core body temperature (Tc) from 38.0 to 41.0 degrees C. The following observations were made: 1) significant increases in renal, lumbar, and splanchnic SND were observed during hyperthermia; 2) autospectral analysis of renal and lumbar SND revealed that the frequency distribution of SND can be altered during progressive increases in Tc; and 3) increases in splanchnic SND to acute heating were similar in baroreceptor-innervated and -denervated rats. We conclude that 1) hyperthermia is a potent stimulus to the sympathetic nervous system and increases the activity in three sympathetic nerves that innervate different regional arterial beds, 2) acute heating influences the neural circuits involved in generating SND as evidenced by changes in the basic pattern of renal and lumbar SND, and 3) the increase in splanchnic SND during hyperthermia is not opposed by the arterial and cardiopulmonary baroreceptors.

Animals↗
PubMed1995

Intravascular ultrasound imaging of peripheral arteries as an adjunct to atherectomy: preliminary experience.

12 atherosclerotic lesions in nine patients, including four restenoses after balloon angioplasty, were treated by atherectomy under the guidance of intravascular ultrasound (US). Echogenicities of the plaques and morphological alterations in the arterial walls produced by atherectomy were evaluated. The two-layered appearance of post-angioplasty restenoses was found to be inner fibrous intimal thickening with proliferation of smooth muscle cells and outer residual collagen-rich plaque. The deep cut surfaces were shown as concave U-shaped defects. Medial tissues were present in all cases where intravascular US demonstrated the disruption of a thin hyperechoic layer of the internal elastic lamina. Intravascular US imaging may provide valuable information on the degree, eccentricity and histological type of stenosis, the presence of calcification before atherectomy, and on the extent of excision and the morphological changes in the arterial wall after atherectomy.

Aged↗
PubMed1995

Superselective intraarterial infusion of cisplatin for squamous cell carcinoma of the mouth: preliminary clinical experience.

OBJECTIVE: The purpose of this study was to assess the initial clinical response to superselective intraarterial infusion of cisplatin for treating stage III and stage IV squamous cell carcinoma of the mouth. SUBJECTS AND METHODS: Thirteen patients received intraarterial cisplatin therapy. The tumors were located in the tongue (n = 7), gingiva (n = 3), buccal mucosa (n = 1), hard palate (n = 1), and floor of the mouth (n = 1). A coaxial technique was used to place microcatheters in the lingual, facial, inferior alveolar, buccinator, and distal internal maxillary arteries, depending on tumor location. The feeding vessels were identified by staining the tumor with infusion of indigocarmine dye in the selected vessel. Relatively low-dose cisplatin (30-40 mg/m2) was injected at the rate of 50 mg/hr. Two or three injections were performed, with a 1-week interval between injections. After chemotherapy, eight patients underwent surgery, four had radiation therapy, and one had both. RESULTS: Thirty-four intraarterial infusions were done successfully without any complications. Arterial infusion of indigocarmine dye was useful for exact identification of feeding vessels, especially when the tumor was extensive, at the margin of the arterial supply, or near the midline. The overall response rate was 92% (complete response [tumor completely resolved], 38%; partial response [tumor reduction > or = 50%], 54%). Ten of 13 patients had no recurrence from 4 to 19 months (mean, 10 months) after treatment. Two patients died of metastatic diseases 6 months after surgery or radiation therapy. One patient had local recurrence 8 months after surgery and postoperative irradiation. No systemic toxicity such as renal failure, liver dysfunction, or bone marrow suppression was observed. Mild and transient local toxicity such as edema or mucositis of the infused area was relatively common. Trigeminal neuralgialike symptoms and reduced mouth opening occurred in two cases and one case, respectively, probably due to direct toxicity to the peripheral trigeminal nerve and masticatory muscles, respectively. CONCLUSION: Superselective intraarterial infusion of low-dose cisplatin is feasible and safe and may have important applications in treating advanced carcinoma of the mouth.

Aged↗
PubMed1995

Usefulness of color Doppler flow imaging in differential diagnosis of multilocular cystic lesions of the kidney.

Color Doppler flow imaging was carried out in 10 multilocular cystic lesions of the kidney. These consisted of three renal cell carcinomas, three hemorrhagic renal cysts, one benign multilocular cystic nephroma, two infected renal cysts, and one benign multilocular renal cyst secondary to von Hippel-Lindau disease. In the patients with renal cell carcinoma, color signals were obtained at the septum and in the solid component within the lesions. A pulsatile wave with a large maximum flow velocity and a high PI value was obtained in two of them. In one of the patients with hemorrhagic renal cysts, color signals were obtained at the region of the septum. In the other benign lesions, however, color signals were obtained only at the peripheral margin, and the flow waveform in these cases was identical to the waveforms found in the interlobar arteries. This study suggested that color display in the lesion well reflects its vascularity in patients with multilocular cystic renal diseases and that measurement of the systolic maximum flow velocity by fast Fourier transform analysis is useful for the differential diagnosis of malignant versus benign lesions.

Adolescent↗
PubMed1995

Contribution of endothelium-derived nitric oxide (EDNO) to the skeletal muscle blood flow response to exercise.

Blood flow (BF) to active muscle increases dramatically during exercise. This increase in BF is permitted by relaxation of smooth muscle (and ensuing vasodilation) in the vasculature of muscle tissue. Recently, attention has focused on the possible role of the endothelium-derived relaxing factor nitric oxide (EDNO) in the vasodilation of muscle vasculature during exercise. A variety of experimental approaches have been used in elucidating the role of EDNO. These include isolated vessel, isolated muscle or muscle group, and conscious exercising animal preparations. Studies utilizing isolated vessels have shown that arterioles from muscle dilate, in an endothelium-dependent manner, to stimuli present during exercise (e.g., increased flow rates). A limitation of such studies, however, is that only the potential for EDNO-induced vasodilation is indicated. The isolated muscle/muscle group approach has consistently demonstrated a role for EDNO in determining resting BF. Findings for muscle BF during contractions are equivocal. A limitation of this approach is that exercise is simulated by stimulating the motor neuron of the muscle of interest. Since this type of muscle activity elicits a relatively small active hyperemia, it may be that a role for EDNO in exercise-induced hyperemia is masked. Findings from exercising animals are equivocal. Some studies demonstrate a role for EDNO in permitting increased muscle blood flow during exercise, while others show no impact of inhibition of EDNO synthesis. Some studies suggest that the importance of EDNO may vary with the muscle (and its fiber type composition) studied. Additional research is needed to clarify the role of EDNO in mediating increased BF to skeletal muscle during exercise.

Animals↗
PubMed1995

[A case of myogenic intractable pain due to thalamic hemorrhage relieved by Vim-Vo thalamotomy].

A 58-year-old female patient with myogenic intractable pain due to thalamic hemorrhage which was relieved by stereotactic Vim-Vo thalamotomy was reported. She had an intractable pain, involuntary movement and deep sensory disturbance in her right arm. We performed stereotactic Vim-Vo thalamotomy using electrophysiological technique to relieve her involuntary movement and myogenic intractable pain. The electrophysiological recordings suggested the followings: (1) The destructive lesion by thalamic hemorrhage was located on from posterior border of Vim nucleus to the upper half of Vc nucleus. (2) Most of Vim neurons remained as intact state. (3) Thalamic electrical activities were relatively enhanced in the Vim nucleus. From these data, we can deduce that the deep sensory inputs reach the border area of Vim nucleus and Vc nucleus in the human thalamus. IMP-SPECT scans were performed before and after the operation. IMP-SPECT scan before operation showed us the contra-lateral cerebellar low perfusional state (crossed cerebellar diaschisis). This crossed cerebellar diaschisis disappeared after the operation. This result suggested that the interaction of cerebellum and Vim nucleus was very close. The above mentioned speculation was more compatible to Jones & Hirai's new parcellation of the human thalamus than to Hassler's.

Cerebral Hemorrhage↗
PubMed1995

Effects of nitric oxide synthase inhibition on the muscle blood flow response to exercise in rats with heart failure.

OBJECTIVE: The aim of this study was to investigate whether the role of nitric oxide (NO) in regulating blood flow (BF) to working skeletal muscle is impaired in chronic heart failure (CHF). METHODS: The effect of NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthesis, was studied in conscious rats with and without CHF due to myocardial infarction (MI). BF to the hindquarter musculature was measured with radiolabelled microspheres during exercise after 4 min of treadmill running (10% grade, 20 m/min) before and after L-NAME (20 mg/kg i.a.) administration. RESULTS: Before L-NAME administration, BF measured in the total hindquarter musculature was less (P < 0.05) during exercise in rats with a large MI (MI size; 44 +/- 2% of the left ventricular endocardial circumference; n = 8) when compared with sham-operated rats (SHAM; n = 10) and rats with a small MI (MI size; 25 +/- 4%; n = 5). The BF measured during exercise following L-NAME administration was similar between the 3 groups. Of the 28 individual hindquarter muscles, BF was reduced in 23 and 19 muscles following the administration of L-NAME for the SHAM rats and rats with a small MI, respectively. In comparison, BF was reduced to only 4 of 28 muscles in rats with a large MI. CONCLUSIONS: These results suggest that the contribution of the NO pathway to the hyperaemic BF responses found in the hindquarter muscles during exercise could be attenuated in rats with CHF. This attenuation of the NO pathway may be associated with the impairment of skeletal muscle BF distribution during exercise in CHF.

Animals↗
PubMed1995

[Complications of percutaneous transluminal angioplasty].

Four hundred twenty-three percutaneous transluminal angioplasties with 383 percutaneous arterial punctures in 346 patients were reviewed to determine the frequency, distribution and causes of complications. Complications were seen at the angioplasty site and puncture site along with miscellaneous complications, the incidence rates being 9.5% (40 of 423 PTAs), 11.7% (45 of 383 punctures), and 2.0% (7 of 346 patients), respectively. Major complications occurred in 20 cases, and surgical procedures were required in six cases. Mortality as a complication of PTA was not seen. Angioplasty site complications included 13 spasms, eight dissections, five thromboses, 13 distal embolizations and one perforation. Most puncture site complications were benign hematomas, but there were other types such as a pseudoaneurysm requiring bypass grafting, a thrombosis requiring thrombolysis and a large quantity of bleeding requiring transfusion. The incidence of angioplasty site complications was significantly higher (p < 0.01) in the procedure for complete occlusion than that for stenosis. The puncture site and miscellaneous complications were also more frequent in complete occlusions. The incidence of complications increased with age, although this tendency did not reach statistical significance.

Adolescent↗
PubMed1995

Primary pulmonary lymphoma: relationship between clinical features and pathologic findings in 24 cases. The Japan National Chest Hospital Study Group for Lung Cancer.

To elucidate the relationship between the clinical features and pathologic findings of primary pulmonary lymphoma, we reviewed 24 patients with this disease. The pulmonary lymphomas were divided into four groups: (1) B-cell lymphoma composed of small to medium-sized lymphoid cells (19 cases); (2) B-cell lymphoma composed of large lymphoid cells (three cases); (3) T-cell lymphoma (one case); (4) malignant lymphoma of lymphomatoid granulomatosis (LYG) type (one case). Radiographs of the first group revealed a predominance of infiltration associated with ill-defined tumor margins upon gross pathology, corresponding histologically to lymphangitic spread. Air bronchogram and pleural tail or abutment were additional radiographic features. Characteristics of the second group were a nodule or mass evident on radiographs and well-circumscribed tumor margins upon gross pathology. Lack of air bronchogram was an another radiographic feature in this group. Seventeen patients in these two groups underwent complete resection of the tumors and survived without recurrence, whereas four received chemotherapy after biopsy and survived with disease. These results indicate that primary pulmonary B-cell lymphoma is a low-grade malignancy and that complete resection is the only therapy which leads to cure. In a single patient with T-cell lymphoma, the radiographic and pathologic features of the tumor were indistinguishable from those in the first group, but the patient had an unfavorable prognosis. We consider that, from a prognostic viewpoint, it is important to determine the T- or B-immunophenotype of the tumor cells for diagnosis of primary pulmonary lymphoma. The only patient in this series with pulmonary lymphoma of LYG type showed distinctive clinicopathologic findings. We consider that this uncommon disease should be separated from other types of primary pulmonary lymphoma.

Adolescent↗
PubMed1995

[Solitary plasmacytoma of the rib--a case report and review of Japanese literatures].

A 72-year-old woman with solitary plasmacytoma of the right fifth rib was surgically treated. She underwent radical resection of the bony chest wall including the right fifth rib, the ribs above and below the involved rib, the intercostal muscle, and the parietal pleura. Histological finding of the tumor was plasmacytoma of the rib. The type of monoclonal protein was IgG and lamda. She is doing well one year and eleven months after surgery without any signs of recurrence. Solitary plasmacytoma is rare as compared with multiple myeloma. Patients with solitary plasmacytoma originating in the rib have a feasibility of operative indication, and radical treatment is expected to be by adequate surgical resection. Seventeen cases of solitary chest wall plasmacytoma described in the Japanese literature are reviewed.

Adult↗