Biomedical subjects

S Fujibayashi

Publications and source records attributed to S Fujibayashi.

At least 19 recordsLinked to original sources

PubMed2001

Bioactive titanium: effect of sodium removal on the bone-bonding ability of bioactive titanium prepared by alkali and heat treatment.

As reported previously, bioactive titanium is prepared by simple alkali and heat treatment, and can bond to living bone directly. The purpose of this study was to accelerate the bioactivity of bioactive titanium in vivo. In in vitro study, sodium removal by hot water immersion enhanced the apatite-forming ability of bioactive titanium in simulated body fluid dramatically. The specific anatase structure of titania gel was effective for apatite formation in vitro. In the current study, we investigated the in vivo effect of sodium removal on the bone-bonding strength of bioactive titanium. Sodium-free bioactive titanium plates were prepared by immersion in an aqueous solution of 5 M NaOH at 60 degrees C for 24 h, followed by immersion in distilled water at 40 degrees C for 48 h before heating them at 600 degrees C for 1 h. Three kinds of titanium plates were inserted into rabbit tibiae, including untreated cp-Ti, conventional alkali- and heat-treated Ti, and sodium-free alkali- and heat-treated Ti. In vivo bioactive performance was examined mechanically and histologically after 4, 8, 16, and 24 weeks. Sodium removal enhanced the bone-bonding strength of bioactive titanium at 4 and 8 weeks postoperatively; however, its bone-bonding strength was inferior to that of conventional alkali- and heat-treated titanium at 16 and 24 weeks. Histological examinations after the detaching test revealed breakage of the treated layer in the sodium-free alkali- and heat-treated titanium group. In conclusion, sodium removal accelerated the in vivo bioactivity of bioactive titanium and achieved faster bone-bonding because of its anatase surface structure, but the loss of the surface's graded structure due to the complete removal of sodium decreased the adhesive strength of the treated layer to the titanium substrate. Further investigations are required to determine the optimum conditions for preparation of bioactive titanium.

Alkalies↗

PubMed2001

Bilateral phrenic nerve palsy as a complication of anterior decompression and fusion for cervical ossification of the posterior longitudinal ligament.

STUDY DESIGN: A case report of bilateral phrenic nerve palsy as a complication of anterior decompression and fusion for cervical ossification of the posterior longitudinal ligament (OPLL). OBJECTIVES: To present a case of a rare and serious complication of cervical spinal surgery and to investigate its cause. SUMMARY OF BACKGROUND DATA: There have been a number of reports of phrenic nerve palsy after cardiac surgery, but the authors have found no previous description of this complication related to spinal surgery. METHODS: The authors describe the clinical presentation and management of a case of bilateral phrenic nerve palsy subsequent to the surgery for cervical OPLL. Also, the literature is reviewed concerning surgical approaches for the treatment of OPLL and the occurrence of phrenic nerve palsy subsequent to any form of therapy. RESULTS: Bilateral phrenic nerve palsy occurred after anterior decompression and fusion for cervical OPLL. Bilateral phrenic nerve palsy was diagnosed radiographically: postoperative chest radiograph showed bilateral laxity of the diaphragm. Movement of the bilateral diaphragm appeared 3 weeks after surgery. The patient successfully returned to normal daily life after ventilatory support for 3 months, although nocturnal oxygen support was still necessary at the latest follow-up, 3 years after surgery. The possible causes of this complication include bilateral C4 nerve root stretching, iatrogenic injury of the gray matter in the ventral horn, alteration of blood circulation related to spinal edema, or re-impingement on the spinal cord at the cranial part of the decompression site. CONCLUSIONS: Bilateral phrenic nerve palsy occurred after anterior decompression and fusion for cervical OPLL. Bilateral phrenic nerve palsy should be kept in mind as a serious complication of spinal surgery. It should be considered when patients unexpectedly fail to wean from the ventilator after surgery.

Cervical Vertebrae↗

PubMed2001

Lumbar posterolateral fusion with biphasic calcium phosphate ceramic.

The authors conducted a retrospective observational study of patients who needed lumbar posterolateral fusion (PLF) using a biphasic calcium phosphate ceramic implant as a substitute for bone graft. The findings of clinical, radiographic, and histologic examinations were reviewed. Thirty-two patients underwent single-level PLF with instrumentation. In all cases, to decrease the occurrence of donor-site complications and morbidity, locally harvested morselized bone from the decompressive site was mixed with hydroxyapatite and beta-tricalcium phosphate (HAP-TCP) granules and sticks and used for fusion at the posterolateral aspect of the lumbar spine. The histologic findings of three biopsy specimens obtained during second operations for metallic implant removal were reviewed. The minimum follow-up period was 26 months. There was no evidence of instrument loosening or breakage. However, bone-graft incorporation was difficult to evaluate radiographically, because image quality was inferior to that with conventional autogenous iliac bone graft. Partial graft bone resorption was revealed on radiographs in 75% of cases. The results showed clinical improvement in all but one case. Solid fusion was observed during the second operation in all three cases. Histologic analysis showed excellent bone incorporation around the HAP-TCP granules. These findings suggest that, although the bulk of the fusion mass with HAP-TCP was smaller than that with autogenous bone, this technique combined with rigid instrumentation is a safe and effective procedure.

Adult↗

PubMed2001

Long-term follow-up study of bioactive bone cement for repairing a segmental defect in a canine femur.

We report on a 7-year long-term follow-up study of a bioactive bone cement (BA cement) that was used to repair a segmental defect in a canine femur. Bilateral femoral segmental defects were repaired with metallic implants that were fixed to the femur using two kinds of bone cement. The BA cement used in this study consists of an apatite- and wollastonite-containing glass ceramic (AW-GC) with a bis-phenol-alpha-glycidyl methacrylate (bis-GMA)-based resin. The bone-cement interface was examined histologically. Previous short-term studies have shown that using BA cement for segmental replacement of the canine femur produced excellent biomechanical and histological results. The BA cement maintained the fixation of a metallic implant to the femur very well. In contrast, the PMMA cement did not maintain alignment under long-term weight-bearing conditions. The results of histological examinations showed direct bonding between the BA cement and bone, while an intervening soft tissue layer was observed at the bone-cement interface with the PMMA cement. The BA cement bonded to the bone through a Ca-P-rich reactive layer, which was twice as thick after 7 years than it was at 26 weeks. No adverse effects of BA cement were observed during the 7-year observation period.

Animals↗

PubMed2000

Bioactive macroporous titanium surface layer on titanium substrate.

A macroporous titanium surface layer is often formed on titanium and titanium alloy implants for morphological fixation of the implants to bone via bony ingrowth into the porous structure. The surface of titanium metal was recently shown to become highly bioactive by being subjected to 5.0 M-NaOH treatment at 60 degrees C for 24 h and subsequent heat treatment at 600 degrees C for 1 h. In the present study, the NaOH and heat treatments were applied to a macroporous titanium surface layer formed on titanium substrate by a plasma spraying method. The NaOH and heat treatments produced an uniform amorphous sodium titanate layer on the surface of the porous titanium. The sodium titanate induced a bonelike apatite formation in simulated body fluid at an early soaking period, whereby the apatite layer grew uniformly along the surface and cross-sectional macrotextures of the porous titanium. This indicates that the NaOH and heat treatments lead to a bioactive macroporous titanium surface layer on titanium substrate. Such a bioactive macroporous layer on an implant is expected not only to enhance bony ingrowth into the porous structure, but also to provide a chemical integration with bone via apatite formation on its surface in the body.

Apatites↗

PubMed2000

Missing anterior cervical plate and screws: a case report.

STUDY DESIGN: A case report of an anterior cervical plate and screws that disappeared completely. OBJECTIVES: To present a case of a missing anterior cervical plate and screws, this being quite a rare complication of a cervical implant. SUMMARY OF BACKGROUND DATA: No mention of this complication was found in the literature. METHODS: Methods in the literature and clinical presentation are reviewed. RESULTS: Dislodgment of an anterior cervical plate occurred in association with an methicillin-resistant Staphylococcus aureus infection. Three months later the implants had disappeared, presumably passing without notice through the gastrointestinal tract. Whole body fluoroscopy could not identify any residual plate or screws. No esophageal fistula could be detected by barium meal swallow study. CONCLUSIONS: The plate and screws became dislodged, eroded through the posterior wall of the esophagus, then traversed the limit of the gastrointestinal tract, passing with feces without significant morbidity. Whether the methicillin-resistant Staphylococcus aureus infection contributed to this unique circumstance or is coincidentally related to it remained a matter of speculation.

Aged↗

PubMed1998

[Relationship between factors examined at health examination and serum pepsinogen levels in healthy adults. Physical measurements, blood chemical tests, drinking and smoking].

OBJECTIVE: We measured serum pepsinogen (PG) levels in healthy adults and examined their physical measurements, blood chemical test values, current drinking and smoking to investigate relationships between these factors and levels of serum PG components (serum PG I, PG II and PG I/II ratio). SUBJECTS AND METHODS: A total of 452 male adults in their 40's, who were determined to be normal or to have only chronic gastritis by endoscopy or X-ray examination of the upper gastrointestinal tract, were studied. PG I and PG II levels in sera were measured, and their relationship with physical measurements and blood chemical test values, and also with current amounts of drinking and smoking, were examined. RESULTS: 1) Height, body weight, body surface area, GOT, GPT and creatinine were found to significantly differ according to serum PG I level; body surface area, GPT and ALP significantly differed according to serum PG II level. However, none of the factors examined showed any significant correlation with the PG I/II ratio. 2) When subjects were divided into positive and negative cases using the evaluation criteria of PG components for gastric cancer screening (determined as positive on the basis of serum PG I level < or = 70 ng/ml and PG I/II ratio < or = 3.0), proposed by Miki et al., none of the factors differed significantly between the two groups. CONCLUSIONS: 1) Serum PG levels were associated with stature, serum transaminase and creatinine. 2) Although serum PG levels were associated with several factors, the effect of physical measurements and blood chemical tests on the results of the evaluation criteria of PG components proposed by Miki et al, were not remarkable.

Adult↗

PubMed1996

Correction of kyphotic deformity of the cervical spine in ankylosing spondylitis using general anesthesia and internal fixation.

Surgical correction of kyphotic deformity of the cervical spine caused by ankylosing spondylitis is usually done using local anesthesia to prevent undue spinal cord compression and paralysis followed by a sudden-extension maneuver. We report a case of kyphotic deformity that was corrected while the patient was under general anesthesia. To prevent cord compression and paralysis and to obtain an accurate and gradual correction, we used a Hartshill rod prebent to the desired angle, and correction was done by tightening sublaminar wires on the rod until the lamina made full contact with it. Somatosensory evoked potential and wake-up tests were also performed. Our successful result shows that correction of kyphotic deformity of the cervical spine in ankylosing spondylitis can be done more accurately and without discomfort using the present method.

Anesthesia↗

PubMed1992

[A case of significant, non-neoplastic, ovarian hypertestosteronism].

A 24-year-old female with significant ovarian hypertestosteronism, who responded well both to gonadotropin releasing hormone (GnRH) agonist and cyclic administration of estrogen and gestagens in terms of suppressing circulating testosterone levels is reported. The patient's menstrual periods had been regular since menarche at the age of 12 until she became amenorrheic at the age of 20. She visited our facility in November 1988 after receiving three cycles of estrogen and gestagen replacement therapy from a previous physician which caused withdrawal bleeding. Clomiphen citrate reportedly failed to induce apparent ovulation. On her first visit with us, she was 160 cm tall weighing 47 kg with apparent hoarseness but not with hirsutism. Pelvic examination revealed significant clitoromegaly but otherwise normal external and internal genitalia. Laparoscopic examination disclosed that her uterus appeared to be normal with bilateral ovaries relatively small (4 x 4 x 3 cm) without tumorous or polycystic appearance. Histological examination of her ovaries obtained at laparoscopy showed several primary follicles with mild infiltration of the stromal cells. No thickened tunica albuginea or cystic formation were observed. These findings did not support either polycystic ovary or hyperthecosis. Serum testosterone (T) levels were extremely high (7.1 ng/ml), while serum androstenedione levels were only slightly above normal range (3.1 ng/ml). Urine 17-KS excretion was slightly increased (6.1 mg/day), while 17-OHCS output was within normal range (4.0 mg/day). Basal serum LH and FSH levels were within normal range and LH pulse frequency was reduced to 1 in 4 hours. Administration of dexamethasone 1 mg/day for 2 days did not suppress circulating T and free T levels but lowered serum cortisol concentration and urine excretion of 17-OHCS. Blood glucose and insulin levels were within normal limits and their responses to oral glucose administration were normal. Abdominal and pelvic ultrasonography and computed tomography as well as adrenal scintigraphy did not reveal any tumorous lesions in bilateral adrenals and ovaries. Administration of GnRH agonist, Buserelin 900 micrograms/day, suppressed circulating T concentrations to 0.7 ng/ml in 8 days, while it had no significant effects on DHEA and DHEA-S levels. After 16 weeks of Buserelin administration, ovulation was successfully induced by hMG administration. Cyclic estrogen and gestagen replacement therapy by Kaufmann's schedule for 2 cycles also suppressed serum T levels to normal, female range. Thus, the present case represents non-neoplastic, non-PCO, ovarian hypertestosteronism which responded well both to GnRH agonist and estrogen and gestagen replacement therapy in terms of lowering circulating T levels.

Adult↗

PubMed1992

t-PA activity and antigen in the newborn and infant.

Concentrations of tissue plasminogen activator (t-PA) activity and t-PA antigen in blood obtained from neonates were investigated in order to elucidate a fibrinolytic condition of the neonates and compare with that of the infants and children. The t-PA activity was measured by bioimmunoassay using monoclonal antibody (SP-322), which bound with an epitope nonintervening with active site of t-PA. The t-PA antigen was detected by ELISA using the same monoclonal antibody (SP-322). As a result, t-PA activity in blood from the newborn baby increased to 0.97 +/- 0.48 IU/ml at the second to the fifth day, and decreased gradually to the baseline levels of healthy adult until 15 years old. The t-PA antigen level was increased from the seventh day. These results suggests that t-PA activity in blood from the neonates may be higher concentrations than those from the infants, children and adults.

Antibodies, Monoclonal↗

PubMed1991

The weak calcemic vitamin D3 analogue 22-oxacalcitriol suppresses the production of tumor necrosis factor-alpha by peripheral mononuclear cells.

The effect of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and its analogue 22-oxacalcitriol (OCT), which was reported to have very weak bone resorbing activity, on the production of tumor necrosis factor (TNF)-alpha was investigated. Mononuclear cells (MNC; 10(6)/ml) were incubated in 5% FCS/RPMI-1640 medium containing 1 microgram/ml lipopolysaccharide (LPS) in the presence or absence of 10(-8) M 1,25(OH)2D3 or 10(-8) M OCT for up to 96 h. Both 1,25(OH)2D3 and OCT suppressed TNF-alpha release by LPS-stimulated mononuclear cells, from the early to late stage of the incubation period, while neither 1,25(OH)2D3 nor OCT shifted the peak time point of TNF-alpha release clearly. MNC (10(6)/ml) were incubated with 1 microgram of LPS in the presence of various concentrations of 1,25(OH)2D3 or 10(-8) M OCT for 48 h. 1,25(OH)2D3 reduced TNF-alpha levels of LPS-stimulated MNC culture supernatant at 48 h in a dose-dependent manner. The half-maximal dose (ED50) for this suppressive effect was 3.7 x 10(-9) M. OCT decreased TNF-alpha levels of culture supernatant at 48 h with a half-maximal dose of 7.8 x 10(-11) M, which indicates that it is approximately 50 times more potent than that of 1,25(OH)2D3. These results indicate that OCT may be applicable as an immunosuppressive agent with limited calcium metabolic activity.

Adult↗

PubMed1989

Different inhibitory actions of immunomodulating agents and immunosuppressive agents on bone resorption of mouse calvaria.

In this study, we have investigated the in vitro effects of the immunomodulators lobenzarit and traxanox and a newly synthesized immunosuppressant, mizoribine, as well as cyclosporin A, on bone resorption using neonatal mouse calvariae labelled with 45Ca. As stimulators of bone resorption, bovine parathyroid hormone (PTH), lipopolysaccharide (LPS), interleukin 1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) were used. Lobenzarit, traxanox, mizoribine and cyclosporin A inhibited or tended to inhibit bone resorption stimulated by PTH, LPS, IL-1 beta or TNF-alpha in a dose-dependent manner. Basal bone resorption was inhibited by immunosuppressant cyclosporin A or mizoribine, while immunomodulators lobenzarit and traxanox failed to inhibit basal bone resorption. Removal of lobenzarit from the culture medium resulted in the recovery of bone resorptive activity. These results suggest that the inhibitory effect of immunomodulators on bone resorption is reversible and nonselective. Also, it raises the possibility that immunomodulators and immunosuppressants may affect bone resorption by different mechanisms.

Adjuvants, Immunologic↗

PubMed1989

[Circadian rhythm and stress in the elderly: a study using salivary cortisol levels as an indicator].

Biological response to stress was studied in the healthy elderly by fluctuations of their circadian rhythms using salivary cortisol levels as an indicator. Social activities per se may not be stressors, but may serve as a "eustress" to the elderly when they are in good health because their rhythm is maintained. Concerning the occupations of the subjects, the rhythms of elderly watchmen showed no disturbance when they slept for three hours between 23:00 and 2:00. However, those who were unable to sleep showed disturbed rhythms. We concluded that disturbance of a rhythm that has been established on the basis of being active during the day time and sleeping at night could be a stressor to the elderly rather than stress due to working as a guard.

Aged↗

PubMed1987

Prostaglandin E2 production by glomeruli and collecting tubules isolated from rat kidney.

The effects of vasopressin, angiotensin II, and calcium ionophore A23187 were examined and compared on endogenous prostaglandin E2 (PGE2) production, in the absence of exogenous arachidonate, by glomeruli and cortical and medullary collecting tubules freshly prepared from rat kidney. Angiotensin II stimulated PGE2 production in the glomeruli but not in the collecting tubules. Vasopressin at concentrations which stimulate cAMP production in collecting tubules failed to stimulate PGE2 production in both glomeruli and collecting tubules. Significant stimulation of PGE2 production occurred in response to calcium ionophore A23187 in both glomeruli and collecting tubules. These results showed that vasopressin failed to stimulate PGE2 production from endogenous precursors in both glomeruli and collecting tubules of the rat kidney while angiotensin II stimulates PGE2 production in the glomeruli but not in collecting tubules. In addition, an ability to produce PGE2 may be greater in medullary than in the cortical portions of collecting tubules as judged by the response to calcium ionophore.

Angiotensin II↗

PubMed1986

Synthesis and processing of sphingolipid activator protein-2 (SAP-2) in cultured human fibroblasts.

Sphingolipid activator proteins (SAP) are relatively small molecular weight proteins that stimulate the enzymatic hydrolysis of sphingolipids in the presence of specific lysosomal hydrolases. SAP-2 has previously been demonstrated to activate the hydrolysis of glucosylceramide, galactosylceramide, and, possibly, sphingomyelin. Using monospecific rabbit antibodies against human spleen SAP-2, the synthesis and processing of SAP-2 were studied in cultured human fibroblasts. When [35S]methionine was presented in the medium to control human cells for 4 h, five major areas of radiolabeling were found. These had apparent molecular weights of 73,000, 68,000, 50,000, 12,000, and 9,000. Further studies indicated that the major extracellular product in normal cells given NH4Cl along with the [35S]methionine and in medium from cultures from patients with I cell disease had an apparent molecular weight of 73,000. The Mr = 68,000 and 73,000 species can be converted to a species with an apparent molecular weight of 50,000 by the action of endoglycosidase F. After labeling cells for 1 h followed by a 1-h chase, the Mr = 12,000 and 9,000 species appear. Treatment of the immunoprecipitated mixture with endoglycosidase F resulted in conversion of these species to one band with an apparent molecular weight of 7,600. These studies indicate that this relatively low molecular weight protein is rapidly synthesized from a relatively large molecular weight highly glycosylated precursor.

Cells, Cultured↗

PubMed1986

Biosynthesis of the sulfatide/GM1 activator protein (SAP-1) in control and mutant cultured skin fibroblasts.

Sphingolipid activator proteins (SAP) are relatively low-molecular-mass proteins that stimulate the hydrolysis of specific sphingolipids by the required lysosomal enzymes. SAP-1 or sulfatide/GM1 ganglioside activator protein has previously been demonstrated to stimulate the enzymatic hydrolysis of sulfatide, GM1 ganglioside and globotriaosylceramide. Using monospecific rabbit antibodies against human liver sulfatide/GM1 activator, the biosynthesis and processing of this activator were studied in cultured skin fibroblasts from controls and patients with GM1 gangliosidosis and a variant form of metachromatic leukodystrophy. When [35S]methionine was presented in the medium to control human fibroblasts for 4 h, the majority of the immunoprecipitable radiolabeling was confined to bands within three regions of apparent molecular mass 65-70, 35-52 and 8-13 kDa. The only immunoprecipitable radiolabeled species excreted into the medium when NH4Cl was present had an apparent molecular mass of 70 kDa. When the excretion products were given to fresh cells followed by incubation for up to 24 h there was production of the mature species. Treatment of the 70 kDa form with endoglycosidase F resulted in production of a 53 kDa molecular mass form. Pulse-chase experiments indicated that the initial immunoprecipitable translation product was 65 kDa which increased to 70 kDa over the next hour. The 65 kDa species must result from co-translational glycosylation of the polypeptide chain. Apparently, intralysosomal processing converts the 13 kDa form to the 8-11 kDa species. The cells from the patient with GM1 gangliosidosis could not process to the smallest species found in controls due to the deficiency of acid beta-galactosidase. Patients who have a variant form of metachromatic leukodystrophy do not make any immunoprecipitable radiolabeled products in the cells or in the media. This indicates a severe mutation in the gene coding for this activator protein. The production of such small mature species from a relatively large precursor form may regulate the production of this interesting protein.

Cells, Cultured↗

PubMed1986

Molecular cloning of the sphingolipid activator protein-1 (SAP-1), the sulfatide sulfatase activator.

A cDNA coding for SAP-1 was isolated from a lambda gt11 human hepatoma expression library using polyclonal antibodies raised against human SAP-1. Three positive clones were isolated with inserts of approximately 0.3 Kb (S1.1), 2 Kb (S1.2) and 2.2 Kb (S-1.3). The latter 2 contained an internal EcoRI site. All three clones cross-hybridized with one another, indicating sequence homology. The nucleotide sequence of S-1.1 was determined. Colinearity was established between 19 amino acids obtained by sequencing the amino terminus of pure SAP-1 and 57 bp from the 5' end of S-1.1. The open reading frame of S-1.1 coded for 67 amino acids. One glycosylation site was found 21 residues from the amino terminus, and no stop codons were found. S-1.1 codes for a mature polypeptide chain with a calculated molecular weight of 8955 daltons, corresponding to approximately 99% of mature SAP-1.

Amino Acid Sequence↗

PubMed1986

Immunocytochemical localization of sphingolipid activator protein-1, the sulfatide/GM1 ganglioside activator, to lysosomes in human liver and colon.

Sphingolipid activator proteins (SAP) stimulate the enzymatic hydrolysis of sphingolipids. The results of biochemical studies have suggested that SAP are located within lysosomes. In this study we sought immunocytochemical verification of the lysosomal location of SAP-1, a SAP that stimulates the hydrolysis of sulfatide and GM1 ganglioside. We stained adjacent sections of normal adult liver and colon for either SAP-1, by peroxidase-labeled antibodies, or acid phosphatase, by enzyme histochemistry. At the light microscopic level, SAP-1 and acid phosphatase were present in similar cells of the colonic lamina propria and hepatic sinusoids, and in similar supranuclear sites of colonic epithelial cells. By electron microscopy, SAP-1 was present in vesicular structures morphologically similar to those containing acid phosphatase. Thus, SAP-1 is present in lysosomes of several different kinds of cells in the normal human liver and colon.

Adult↗