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Biomedical subjects

S Fukuda

Publications and source records attributed to S Fukuda.

At least 901 records · Page 50Linked to original sources
PubMedDate not supplied

A gelatin coated collagen-polyglycolic acid composite membrane as a dural substitute.

We designed a new biodegradable composite membrane for use as a dural substitute. This membrane is composed of polyglycolic acid (PGA) mesh, collagen sponge, and gelatin sponge. Collagen layers are attached on both sides of the PGA mesh. One side of the membrane is coated with freeze-dried gelatin to prevent tissue adhesion. We examined the mechanical properties of the membrane and evaluated its efficacy in vivo by implanting it into dogs. When the mechanical properties of the membrane were measured under wet conditions, tensile strength and resistance against cutting by a suture were approximately 20 N/cm and 13 N, respectively, which are adequate for a surgical material. In the in vivo experiment, our dural substitute was implanted into six adult beagle dogs to repair a 25 x 15 mm defect in the dura mater. Two dogs each were killed at 2 and 4 months after implantation and two were observed over 6 months. At 4 months after implantation, the implanted dural substitute was almost absorbed and a fibrous membrane resembling native host dura had regenerated at the site. No foreign body reaction or significant adhesion to the cerebral cortex was observed. These results indicate the clinical potential of our novel dural substitute.

Absorbable Implants↗
PubMedDate not supplied

The significance of atherogenic indices in patients on hemodialysis.

Atherosclerotic diseases (ASD) are the major cause of mortality and morbidity in patients on hemodialysis (HD). To evaluate the significance and usefulness of atherogenic indices, we examined lipoprotein(a) (Lp(a)), remnant-like particles cholesterol (RLP.C), homocysteine (Hcy), cardiac troponin T (TnT), and ankle-arm blood pressure index (AABI) in 114 patients on HD (male 79, female 35; age 62.1 +/- 1.3 years). As a result, serum cardiac TnT and AABI levels in patients with diabetes mellitus (DM) (n = 33) were significantly higher than those in patients without DM (n = 81). In patients with cerebrovascular diseases (CVD), serum levels of both RLP.C and Hcy, and AABI levels were significantly higher than those in patients without CVD. In patients with coronary artery diseases (CAD), serum cardiac TnT and AABI levels were significantly higher than those in patients without CAD. In patients with peripheral vascular diseases (PVD), serum levels of both Hcy and cardiac TnT were significantly higher than those in patients without PVD. Multiple regression analysis did show that the presence of DM, serum Hcy levels and age were independent factors as- sociated with ASD: ASD = -0.348 + 0.426 x DM (scored: 0, absence; 1, presence) + 0.005 x Hcy (nmol/ml) + 0. 010 x Age (years) (p < 0.001). In conclusion, the presence of DM and advanced age are major determinants for atherosclerosis. In addition, serum Hcy levels are independent risk factors for atherosclerosis irrespective of the absence of DM.

Aged↗
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Several clinical aspects of thalamic pulvinotomy.

Several clinical aspects of thalamic pulvinotomy were investigated. Influence of electrical stimulation of pulvinar on consciousness, speech, memory, evoked response, emotion, intelligence, character, ophthalmic and auditory examinations were studied during operation and compared between pre-, post, and during operation.

Adolescent↗
PubMedDate not supplied

Arginine vasopressin increases perinuclear [Ca2+] in single cultured vascular smooth muscle cells of rat aorta.

The effects of arginine vasopressin (AVP, 10(-7) M) on the spatial dynamics of intracellular [Ca2+] in single cultured smooth muscle cells of the rat aorta were studied by digital imaging microscopy using the fluorescent Ca2+ indicator fura-2. The nuclear and cytosolic regions were distinguished by the fluorescent image excited at 380 nm. Changes in intracellular [Ca2+] were expressed as percent increases in the ratios of fluorescence intensity at 500 nm excited by 340 and 380 nm. AVP increased the nuclear and cytosolic [Ca2+] in Ca(2+)-containing (control) (285 +/- 27 and 172 +/- 22%, respectively) or Ca(2+)-free (203 +/- 26 and 121 +/- 15%, respectively) solutions. However, caffeine (20 mM) and ryanodine (20 microM) greatly attenuated the [Ca2+] increase induced by AVP in both regions (61 +/- 21 and 42 +/- 15%, respectively). On the ratio image, the nuclear region was discriminated from other regions at the peak response to AVP in preparations treated with caffeine and ryanodine, whereas the outline of the nuclear region was indistinct in untreated preparations. The finding implies that caffeine- and ryanodine-responsive Ca2+ storage sites may exist in the region surrounding the nucleus. The results suggest that the region surrounding the nucleus may be one of the important Ca2+ storage sites with regard to the responses of rat aortic smooth muscle cells to AVP.

Animals↗
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Relation between spinal cord and epidural blood flow.

To test applicability of monitoring regional spinal cord blood flow by measuring regional epidural blood flow, both were simultaneously measured by the hydrogen clearance method in response to changes in PaCO2 and mean arterial blood pressure in rats anesthetized with pentobarbital. An excellent correlation was found between regional spinal and epidural blood flow over a physiological range of PaCO2 (27.8-66.7 torr) and blood pressure (30-130 torr), while a poor correlation was demonstrated between regional spinal or epidural blood flow and regional muscle blood flow in response to these same physiological parameters. Moreover, the rates of change in regional spinal and epidural blood flows were almost the same in response to both PaCO2 and blood pressure. These results suggest that both regional spinal and epidural blood flow are regulated by a similar mechanism and suggest that regional spinal cord blood flow can be monitored by regional epidural blood flow.

Animals↗
PubMedDate not supplied

Experimental Sendai virus-induced labyrinthitis in guinea pigs. An ultrastructural study of cochlear lesions.

Guinea pigs were inoculated with a Sendai virus into the scala tympani and subsequent pathological changes of the cochleas were investigated by electron microscopy. Replication of the virus was indicated by buddings at the endolymphatic surface and by the intracytoplasmic occurrence of filamentous substances, ie, nucleocapsids. Budding viruses or free virus particles observed in a series of our experiments were identified as Sendai viruses by means of the immunological labeling with ferritin. Viral lesions, which were defined as the pathological changes of the cells associated with virus multiplication, were found in eight cochleas out of 20. This study revealed that the early lesions of the cochleas infected by Sendai viruses were primarily confined to Reissner's membrane and the stria vascularis, but the sensory cells were not affected.

Animals↗
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Non-Hodgkin's lymphoma accompanied by autoimmune hemolytic anemia with anti-e autoantibody.

A 43-year-old male with non-Hodgkin's lymphoma accompanied by autoimmune hemolytic anemia (AIHA). His blood group was group B, CcDEe. Alloantibody was absent in his serum, but autoantibody, a combination of IgG and C3d type which showed anti-e specificity, was present. Although transient improvement of AIHA was achieved by treatment with 60 mg/day of prednisolone, subsequent worsening of the anemia resulted in the patient's death. Identification of blood group-specific autoantibodies may be beneficial in such a case for blood transfusion.

Adult↗
PubMedDate not supplied

Cryosurgery on postganglionic fibers (posterior nasal branches) of the pterygopalatine ganglion for vasomotor rhinitis.

Clinical experience with a newly designed device for cryosurgery on autonomic nerves in cases of vasomotor rhinitis is reported. The device consists of a handy spray of liquid nitrogen and a slender probe 2.5 mm in diameter. The posterior nasal branches of the pterygopalatine ganglion were destructed by freezing for 5-8 sec with a jet of supercooled nitrogen gas delivered onto the pterygopalatine foramen under anesthesia with 4% lidocaine. Satisfactory results were obtained by this procedure in 77 of 102 cases of vasomotor rhinitis which had failed to respond to antihistaminics. This original technique of cryosurgery which is not time-consuming and can be performed on an ambulatory basis will prove useful in clinical practice.

Animals↗
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Spiral modiolar vein: its importance in inner ear inflammation.

The inner ear responds immunologically to foreign proteins and pathogens introduced into the cochlea. The route of entry of the cells participating in the inner ear inflammatory process is the spiral modiolar vein with its collecting venules. Since this vein is located adjacent to the scala tympani, the end result of cellular infiltration is fibro-osseous obliteration of this scala preferentially. This observation has implications for the placement of cochlear implant electrodes of patients with labyrinthitis as the cause of hearing loss.

Adult↗
PubMedDate not supplied

Ataxia telangiectasia associated with B-cell lymphoma: the effect of a half-dose of the drugs administered according to the acute lymphoblastic leukemia standard risk protocol.

Ataxia telangiectasia (A-T) is a rare autosomal recessive disorder characterized by cerebellar ataxia, oculocutaneous telangiectasia, and variable degrees of humoral and cellular immunodeficiency. Affected individuals are known to exhibit a high incidence of lymphoma and leukemia. Because of increased chemosensitivity, the treatment of A-T patients with malignancies requires extremely careful planning and caution with respect to the use of chemotherapy. The authors report on a 12-year-old boy with A-T who developed B-cell lymphoma. He received a half-dose of the drugs administered according to the acute lymphoblastic leukemia (ALL) protocol issued by our children's cancer study group (9104 Standard Risk Protocol, Tokai Pediatric Oncology Study Group). As a result, he continues to be in complete remission and free of treatment complications 32 months after the diagnosis of B-cell lymphoma.

Antineoplastic Combined Chemotherapy Protocols↗
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Percutaneous microwave coagulation therapy for primary or recurrent hepatocellular carcinoma: long-term results.

BACKGROUND/AIMS: To clarify the indication of percutaneous microwave coagulation therapy for hepatocellular carcinoma. METHODOLOGY: Thirty-three hepatocellular carcinoma patients who underwent percutaneous microwave coagulation therapy were enrolled in this study, including 18 primary and 15 recurrent hepatocellular carcinoma patients. We examined the local recurrence rates and the long-term results after the treatment. RESULTS: The overall survival rates of the primary group at 1, 2, 3, 4 and 5 years were 94.4%, 77.8%, 77.8%, 77.8% and 48.6%, respectively, whereas those of the recurrent group were 100%, 85.7%, 66.7% and 50.0% at 1, 2, 3 and 4 years, respectively. Local recurrence after percutaneous microwave coagulation therapy was found in about 50% of patients in both groups. Seventeen of the 27 patients (63.0%) with a moderately or poorly differentiated hepatocellular carcinoma tumor had local recurrence, while none of the 6 patients with a well-differentiated hepatocellular carcinoma tumor did (P = 0.005). CONCLUSIONS: Irrespective of primary or recurrent hepatocellular carcinoma, the indication of percutaneous microwave coagulation therapy as an alternative to hepatic resection should be limited to cases of a well-differentiated hepatocellular carcinoma tumor smaller than 2 cm in diameter.

Aged↗
PubMedDate not supplied

Bovine internal thoracic artery graft. Successful use at urgent coronary bypass surgery.

Bovine internal thoracic artery grafts (Bioflow) were successfully utilized in two patients for emergency coronary artery bypass grafting (CABG). One patient was an 80-year-old man with severe varicose veins and a calcified ascending aorta. Heart failure occurred after triple CABG with bilateral internal thoracic and gastroepiploic arteries. The addition of a Bioflow graft to the circumflex artery restored good cardiac function. The second case was a 54-year-old man whose patent old saphenous vein graft was accidentally injured at reoperation. Emergency use of the Bioflow to bypass the right coronary artery in combination with the right gastroepiploic artery graft to the anterior descending artery resulted in an excellent outcome. The two Bioflow grafts were patent at the 20th and 10th postoperative days, respectively. These cases strongly suggest the efficacy of Bioflow during emergency situations in CABG.

Aged↗
PubMedDate not supplied

Potentiation of pressor responses to serotonin by ketamine in isolated perfused rat mesentery.

The effects of ketamine on vasoconstrictor responses to periarterial sympathetic nerve stimulation (PNS), norepinephrine (NE), and 5-hydroxytryptamine (5-HT) were studied in normotensive Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). The isolated mesenteric arteries were perfused at a constant rate (5 ml/min), and the perfusion pressure was recorded. The pressor responses to PNS (8 Hz, 2 ms, 30 s) were augmented by ketamine (2 X 10(-5) and 10(-4) M) in WKY and SHR. Those to intraarterially infused NE (3 X 10(-10) M) were statistically unaltered. However, in three of seven arterial preparations from WKY and in six of nine preparations from SHR, ketamine (2 X 10(-5) and 10(-4) M) decreased the pressor responses to NE. In contrast, the responses to intraarterial 5-HT (1.3 X 10(-9) mol) were potentiated by ketamine (2 X 10(-5) and 10(-4) M) in SHR and WKY--to a much greater extent in SHR. Fractional release of tritium by PNS from isolated mesenteric arteries previously labeled with 1-[7,8-(3)H]NE (10(-7) M) was unaltered by ketamine (10(-4) M) in SHR and WKY. Cocaine (10(-5) M) prevented the ketamine-induced potentiation of PNS and 5-HT responses. Ketamine as well as cocaine inhibited the accumulations of [3H]5-HT and [3H]NE in intact mesenteric arteries from SHR and WKY to a comparable extent. In tissues denervated by 6-hydroxydopamine, the accumulation of 5-HT was about 70% (WKY) and 60% (SHR) of those in intact tissues, whereas that of NE was about 11% (WKY) and 9% (SHR).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
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Chronic effect of left ventricular assist pumping on right ventricular function.

We evaluated right ventricular (RV) function during left ventricular assist device (LVAD) pumping during acute and chronic experiments in both normal hearts and hearts with left ventricular failure. An LVAD was implanted between the left atrium and the descending aorta of goats. The LVAD was pumped in a counterpulsation mode and at maximum bypass flow for 4-6 weeks in chronic experiments. The following results were obtained: 1) LVAD pumping itself did not affect RV function, even after 6 weeks of pumping, 2) the dimensions of the RV free-wall segments measured by sonomicrometers showed a gradual and small increase during the early postoperative days, which was due to an increase in volume returned to the RV and the deformity of the RV cavity derived from reduction in LV volume, and 3) the same tendencies were seen even with LV failure hearts. These results suggested that 1) LVADs can assist not only the LV but also the RV by reducing RV afterload, 2) excessive and prolonged assistance by an LVAD seems to dilate the RV free-wall, and 3) preexisting RV dysfunction is the main cause of signs of RV failure during LV pumping.

Animals↗