Biomedical subjects

K Kusumoto

Publications and source records attributed to K Kusumoto.

At least 37 records · Page 2Linked to original sources

PubMed2000

Immunohistochemical expression of bone morphogenetic protein-2 in pilomatricoma.

BACKGROUND: The mechanism of occurrence of calcification and ossification in pilomatricoma remains unclear. OBJECTIVES: To elucidate the pathogenesis of calcification and ossification in pilomatricoma we examined the role of bone morphogenetic protein (BMP)-2, which plays important parts in inducing ectopic bone formation both in vivo and in vitro. METHODS: Twenty cases of pilomatricoma were studied immunohistochemically using anti-BMP-2 monoclonal antibody. RESULTS: In normal skin, including hair follicles, there was no BMP-2 expression. In all pilomatricomas, BMP-2 was found exclusively in the cytoplasm of shadow cells but not in basophilic cells. In two cases of bone formation seen in pilomatricoma, osteoblasts in the periosteal area showed a strong positive reaction, while bone trabeculum (bone matrix) showed no reaction. CONCLUSIONS: Our findings indicate that shadow cells positive for BMP-2 may play an important part in generating bone formation in pilomatricoma.

Adolescent↗

PubMed2000

A non-toxic heat shock protein 70 inducer, geranyl-geranyl-acetone, restores the heat shock response in gastric mucosa of protein-malnourished rats.

Acute gastric mucosal lesions caused by stress or noxious stimuli are important to consider in the management of critically or chronically ill patients. Protein malnutrition has been implicated as a risk factor for stress ulcer and subsequent complications in those patients. When male Wistar rats fed a 5% or 20% casein diet for 3 weeks were exposed to restraint and water-immersion stress, the low-protein diet significantly increased the ulcer index. The low-protein diet did not change the level of heat shock factor 1 (HSF1) in gastric mucosa but it did attenuate the HSF1 activation after exposure to the stress, resulting in the inhibition of HSP70 mRNA expression and HSP70 induction in gastric mucosa. HSP70 is crucial for the maintenance of cell integrity during pathophysiologic conditions; therefore the impaired HSP70 induction appeared to at least in part aggravate stress ulcer. We also tested whether a non-toxic HSP70 inducer, geranyl-geranyl-acetone (GGA), effectively improved the mucosal integrity by stimulating HSP70 induction under protein malnutrition. Intragastric administration of GGA (200 mg/kg twice a day) to the protein-malnourished rats for up to 1 week failed to stimulate the HSP70 induction. However, the administration of GGA (200 mg/kg twice a day) for 3 weeks restored HSP70 induction and induced higher resistance against stress ulcer as compared with results in vehicle-treated, normally nourished rats. Our results suggest that GGA may have a potential benefit for the prevention of stress ulcer in chronically or critically ill patients with protein malnutrition.

Animals↗

PubMed2000

The effect of blood supply in muscle and an elevated muscle flap on endogenous tissue-engineered bone by rhBMP-2 in the rat.

Metabolism and remodeling of bony tissue are maintained and controlled by blood supply. In this study, bony tissue osteoinduced heterotopically by recombinant human bone morphogenetic protein-2 (rhBMP-2) in rat muscles with different amounts of blood supply was investigated. The implant beds were in the latissimus dorsi muscle (LDM) and in the space wrapped with an elevated latissimus dorsi muscle flap (LDMF). The blood flow was preestimated at two muscle sites using a laser Doppler blood flowmeter. The flow value of the LDM was 2.23 +/- 0.17 ml/min/100 g (mean +/- standard deviation). The flow values of the LDMF were 1.71 +/- 0.22 ml/min/100 g 30 minutes after elevating the LDMF, 1.75 +/- 0.20 ml/min/100 g after 1 week, 1.83 +/- 0.19 ml/min/100 g after 2 weeks, and 1.99 +/- 0.18 ml/min/100 g after 3 weeks. Bony tissues induced heterotopically by rhBMP-2 were examined radiographically and histologically. On radiographs, radiopaque shadows in the LDM were almost as large as those in the LDMF. The radiopacity in the LDM was a little higher than that of the LDMF. The microscopic findings showed increased trabeculae and more hematopoietic marrow in the LDM than lamellalike bone in the LDMF. Mean bony area in the implant was 1.05 +/- 0.26 mm2 in the LDM, and was 0.70 +/- 0.11 mm2 in the LDMF. Bony proportions in the overall implant area were 18.3 +/- 3.46% in the LDF and 12.1 +/- 2.18% in the LDMF. The current study indicates that blood supply is an important factor for promoting heterotopic osteoinduction by rhBMP-2 to produce massive bony tissue as an endogenous method of tissue engineering.

Animals↗

PubMed2000

Osteogenesis by recombinant human bone morphogenetic protein-2 at skeletal sites.

Osteogenesis was evaluated in the mandibular bone by combinations of various dosages of recombinant human bone morphogenetic protein-2, atelopeptide Type I collagen, and porous hydroxyapatite (four groups: Group I, 2 micrograms recombinant human bone morphogenetic protein-2, atelopeptide Type I collagen, and porous hydroxyapatite; Group II, 10 micrograms recombinant human bone morphogenetic protein-2, atelopeptide Type I collagen, and porous hydroxyapatite; Group III, 50 micrograms recombinant human bone morphogenetic protein-2, atelopeptide Type I collagen, and porous hydroxyapatite; Control Group, only atelopeptide Type I collagen and porous hydroxyapatite). The prepared materials were implanted in the mandibular bone hole (7 mm in diameter, 2 mm deep). Three weeks later, the alkaline phosphatase activity in the implanted region was determined, and the histologic features of the excised tissue were examined. There were significant differences in histologic and biochemical findings among the four groups. In the recombinant human bone morphogenetic protein-2 implanted groups, osteogenesis increased with the dosage of recombinant human bone morphogenetic protein-2, as assessed by alkaline phosphatase activity and histologic findings. The results suggest that atelopeptide Type I collagen is an effective carrier for recombinant human bone morphogenetic protein-2 and that porous hydroxyapatite would be advantageous for clinical application as a material to maintain its original form after implantation.

Alkaline Phosphatase↗

PubMed2000

Osteoinduction by recombinant human bone morphogenetic protein-2 at intramuscular, intermuscular, subcutaneous and intrafatty sites.

To compare the osteoinductive activity of recombinant human bone morphogenetic protein-2 (rhBMP-2) at various sites in rats, 5 microg of rhBMP-2 were implanted into various sites, using atelopeptide type-I collagen (CL) as a carrier (BMP groups). CL implantation was used as a control. Forty Wistar rats were divided into intramuscular, intermuscular, subcutaneous and intrafatty site groups (IrM, IeM, SC and IF, respectively). Bone formation was evaluated radiographically, histologically and biochemically 21 days after implantation. In the BMP groups, the alkaline phosphatase activity and calcium content at all sites were higher than those in the control groups. Among the BMP groups, the new bone formation was highest in the IrM and lowest in the IF radiographically, histologically and biochemically. Five microg of rhBMP-2, a relatively low dose, induced adequate new bone formation in all sites. The variations of osteoinductive activity of rhBMP-2 in various sites may be due to differences in the blood supply.

Adipose Tissue↗

PubMed1999

The myocardial Na(+)-H(+) exchange: structure, regulation, and its role in heart disease.

The Na(+)-H(+) exchange (NHE) is a major mechanism by which the heart adapts to intracellular acidosis during ischemia and recovers from the acidosis after reperfusion. There are at least 6 NHE isoforms thus far identified with the NHE1 subtype representing the major one found in the mammalian myocardium. This 110-kDa glycoprotein extrudes protons concomitantly with Na(+) influx in a 1:1 stoichiometric relationship rendering the process electroneutral, and its activity is regulated by numerous factors, including phosphorylation-dependent processes. There is convincing evidence that NHE mediates tissue injury during ischemia and reperfusion, which probably reflects the fact that under conditions of tissue stress, including ischemia, Na(+)-K(+) ATPase is inhibited, thereby limiting Na(+) extrusion, resulting in an elevation in [Na(+)](i). The latter effect, in turn, will increase [Ca(2+)](i) via Na(+)-Ca(2+) exchange. In addition, NHE1 mRNA expression is elevated in response to injury, which may further contribute to the deleterious consequence of pathological insult. Extensive studies using NHE inhibitors have consistently shown protective effects against ischemic and reperfusion injury in a large variety of experimental models and has led to clinical evaluation of NHE inhibition in patients with coronary artery disease. Emerging evidence also implicates NHE1 in other cardiac disease states, and the exchanger may be particularly critical to postinfarction remodeling responses resulting in development of hypertrophy and heart failure.

Animals↗

PubMed1999

Comparative study of intramuscular and intraskeletal osteogenesis by recombinant human bone morphogenetic protein-2.

OBJECTIVE: The purpose of this study was to compare the osteoinducing activity of recombinant human bone morphogenetic protein-2 (rhBMP-2) at intramuscular and intraskeletal sites in rats. STUDY DESIGN: Five tg of rhBMP-2 was implanted into the right calf muscle of each of 20 rats and into a hole (4 mm in diameter, 1.5 mm in depth) that was made in the mandibular body of each of 20 other rats, with atelopeptide type I collagen as a carrier. The alkaline phosphatase activity and calcium content were quantitatively analyzed 1, 3, 7, and 21 days after the implantation of rhBMP-2 into either mandibular bone (in the intraskeletal group) or calf muscle (in the intramuscular group). The new bone formation was evaluated histologically 21 days after implantation. RESULTS: On days 1 and 3, the alkaline phosphatase activity and calcium content in the intraskeletal group showed no significant differences from those in the intramuscular group. On the 7th and 21st days after implantation, however, the alkaline phosphatase activity and calcium content in the intraskeletal group were significantly higher than those in the intramuscular group. Histometry of the microscopic views showed that the mean trabecular area was 0.87 mm2 in the intramuscular group and 2.66 mm2 in the intraskeletal group. CONCLUSIONS: These results suggest that the new bone formation stimulated by rhBMP-2 in the intraskeletal group was greater than in the intramuscular group.

Alkaline Phosphatase↗

PubMed1999

An autopsy case of malignant mesothelioma with osseous and cartilaginous differentiation: bone morphogenetic protein-2 in mesothelial cells and its tumor.

An autopsy case of biphasic malignant mesothelioma with osseous and cartilaginous differentiation diffusely involving the peritoneal cavity was confirmed by light microscopic histochemistry, immunohistochemistry, and electron microscopy. A reverse transcription-polymerase chain reaction using specific primers for bone morphogenetic protein-2 (BMP-2) revealed weak positive transcript in normal mesothelial cells and up-regulated expression around bone-forming malignant mesothelioma tissue. However, BMP-2 protein expression was detected only in the marginal zone of bone trabeculae and spindle-shaped mesothelioma cells distributed around bone trabeculae in tumor tissue. The distribution of type IV collagen in tumor tissue was in accordance with the BMP-2 expression. Normal mesothelial cells and tumor cells expressed BMP-2 mRNA, but the BMP-2 protein expression was restricted to the bone-forming area in the malignant mesothelioma.

Abdominal Neoplasms↗

PubMed1999

Comparison of recombinant and purified human bone morphogenetic protein.

Clinically, it would be more convenient to use recombinant than purified preparations of bone morphogenetic protein (BMP). Recently, recombinant human BMP (rhBMP) has attracted the attention of many investigators, but it has not been fully characterized. We examined the bone-inducing activity of rhBMP-2 and compared it with that of purified BMP derived from human bone matrix (phBMP). Two, 10, or 50 microg of rhBMP-2 or phBMP was mixed with 3 mg of atelopeptide type I collagen (carrier), and specimens were implanted in the calf muscles of Wistar rats (n=5 in each group). Four weeks later, new bone had formed in all the rhBMP-2- and phBMP-implanted muscles and was visible radiographically and histologically. The quantitative analysis indicated that the activity of rhBMP-2 was less than one tenth that of phBMP. It is necessary to find out why rhBMP-2 has fewer activities than phBMP.

Alkaline Phosphatase↗

PubMed1999

Enhancement by recombinant human bone morphogenetic protein-2 of bone formation by means of porous hydroxyapatite in mandibular bone defects.

Hydroxyapatite is osteoconductive and can maintain an original biocompatible form. It is useful, in the reconstruction of bone defects, to enhance the osteoconduction of hydroxyapatite with an osteogenic protein. The aim of this study was to evaluate the bone formation in surgically created defects of rabbit mandibles by a combination of recombinant human bone morphogenetic protein-2 (rhBMP-2), with porous hydroxyapatite and atelopeptide type I collagen used as the carrier for rhBMP-2. A 10-microg rhBMP-2-implanted group (n = 15) and a control group (n = 15), in which only atelopeptide type I collagen and porous hydroxyapatite were implanted, were histologically examined 3, 7, and 21 days after implantation. The alkaline phosphatase activity was also quantitatively analyzed. No new bone formation was observed in either the tested or the control group after 3 days. At 7 days, immature bone tissue was observed in some pores of the rhBMP-2implanted group, while in the control group, immature mesenchymal cells were observed. At 21 days, trabecular bone lined some pore walls. In the central portion, the bone marrow, including angioid tissue, was observed. New trabecular bone formation was observed on portions of the external surface of the hydroxyapatite disk. On the other hand, the control group showed infiltration of immature mesenchymal cells into some pores. Marginal bone formation was found in the pores close to the surface of the disk which opposed mandibular bone. The control group showed a slow, small increase in alkaline phosphatase activity in this study, while the experimental group showed a marked increase at 21 days. This increase was significantly higher in the tested group than in the control group at both 7 and 21 days. The findings indicate that rhBMP-2 accelerated bone formation by osteoconduction from porous hydroxyapatite. The combination of rhBMP-2, atelopeptide type I collagen, and porous hydroxyapatite is suggested to be advantageous for clinical application in reconstructing mandibular bone defects.

Alkaline Phosphatase↗

PubMed1998

Transcript of a homolog of aflR, a regulatory gene for aflatoxin synthesis in Aspergillus parasiticus, was not detected in Aspergillus oryzae strains.

Some strains of Aspergillus oryzae were shown to have homologs of aflR, a regulatory gene for aflatoxin synthesis in Aspergillus parasiticus. Transcription of an aflR homolog was examined in six strains of A. oryzae having the homologs, using polymerase chain reaction (PCR) coupled with reverse transcription. No PCR product was obtained when the RNA prepared from the A. oryzae strains cultivated under aflatoxin-producing condition was used as template for amplification of the aflR cDNA. By contrast, a PCR product of the expected size was obtained with RNA from A. parasiticus NIAH-26 processed by the same procedure. From genomic DNA of these strains, PCR products of the same size as above were obtained. Possible degradation of the aflR mRNA in the RNA preparation of the A. oryzae strains was negligible, because the calmodulin transcript was detected by PCR from the same RNA samples. Thus, the aflR homologs in the non-aflatoxigenic A. oryzae strains examined are not expressed even under aflatoxin-producing condition.

Aflatoxins↗

PubMed1998

Neutrophils responded to immobilized lipopolysaccharide in the absence of lipopolysaccharide-binding protein.

Lipopolysaccharide (LPS) in solution primes neutrophils for enhanced release of superoxide in response to N-formyl-methionyl-leucyl-phenylalanine. We show that LPS immobilized on polystyrene or polypropylene acted on neutrophils by a mechanism different from that of LPS in solution. Coating the surface with 1% plasma, either before coating with LPS (plasma/LPS) or after coating with LPS (LPS/plasma), was essential to induce the LPS response in neutrophils. However, plasma could be replaced by fibrinogen, type I collagen or type IV collagen, or, to a lesser extent, by fibronectin or vitronectin, which was not true for LPS in solution. About 20% of the LPS added was immobilized on the plastic surfaces, based on its ability to adsorb anti-LPS antibody after extensive washing. The amount of soluble LPS that might have been released from surfaces during the incubation with neutrophils was too low to account for the priming by immobilized LPS. About 13-20 min was needed for neutrophils to become primed after incubation with immobilized LPS. Immobilized LPS induced up-regulation of CD11b/CD18 and latent alkaline phosphatase and also enhanced the adhesive response of neutrophils. Priming by immobilized LPS was inhibited by anti-CD14 antibody or by treatment of neutrophils with the LPS antagonist LA-14-PP. When immobilized LPS was treated with anti-LPS-binding protein (LBP) antibody, the response of neutrophils to LPS/plasma was inhibited but the response to plasma/LPS or fibrinogen/LPS was not. Thus, the LPS in plasma/LPS or fibrinogen/LPS acted on neutrophils in an LBP-independent manner. We conclude that the CD14-dependent LPS receptor system of neutrophils was capable of working in the absence of LBP, but only when LPS was immobilized on a surface coated with protein.

Acute-Phase Proteins↗

PubMed1998

Osteoinduction capability of recombinant human bone morphogenetic protein-2 in intramuscular and subcutaneous sites: an experimental study.

The osteoinduction capability of recombinant human bone morphogenetic protein-2 (rhBMP-2) in the muscle and in the subcutaneous tissue in Wistar rats (n = 20) was evaluated, using atelopeptide type-I collagen as a carrier. The alkaline phosphatase (ALP) activity and calcium (Ca) content were quantitatively analyzed 1, 3, 7 and 21 days after the implantation of 5 micrograms of rhBMP-2. At 3 days, the ALP activity began to increase gradually. The Ca content showed a slow increase until 7 days and was markedly elevated at 21 days. There was no significant difference observed between the intramuscular and subcutaneous sites until 3 days. However, at 7 days, both the ALP activity and Ca content were significantly higher intramuscularly than subcutaneously. Also, at 21 days they were higher in the muscle than in the subcutaneous tissue. These results suggest that the difference in osteoinduction could be related to the partial pressure of oxygen or the blood supply in the intramuscular and subcutaneous sites, and that immature mesenchymal cells in the muscle could more easily differentiate into osteoblasts, leading to osteoinduction. This study clearly demonstrated that even a small amount (5 micrograms) or rhBMP-2 induces new bone in the subcutaneous tissue, which has a lesser blood flow than the muscle.

Alkaline Phosphatase↗

PubMed1998

Prefabricated muscle flap including bone induced by recombinant human bone morphogenetic protein-2: an experimental study of ectopic osteoinduction in a rat latissimus dorsi muscle flap.

For skeletal reconstruction, a vascularised bone graft is both reliable and useful, but some sacrifice usually occurs at the skeletal donor site. In the search for our alternative, we investigated ectopic osteoinduction by bone morphogenetic protein in a rat muscle flap, to prefabricate a muscle flap that included bone. Right latissimus dorsi muscle flaps were prepared in 16 rats. Recombinant human bone morphogenetic protein-2 (rhBMP-2; 2, 10 and 50 micrograms) mixed with atelopeptide type I collagen (3 mg) as the carrier was wrapped with the tip of the latissimus dorsi muscle flap. Three weeks later, ectopic osteoinduction in the latissimus dorsi muscle flap was investigated radiologically, histologically and biochemically. A radiological oval shadow was observed in each animal in each rhBMP-2-implanted group. The volume of the oval shadow area in the muscle flap was dependent upon the dosage of rhBMP-2. It indicated that on ectopic osteoinduction by rhBMP-2 in the muscle flap, induced trabeculae were circularly constructed at the margins of the lump. The radio-opacity of the oval shadows was almost equal in all rhBMP-2-implanted groups, and the shadow areas depended on the dosage of rhBMP-2. The biochemical indices of osteogenesis, ALP activity and Ca content in the lump were dependent upon the dosage of rhBMP-2. This study showed that ectopic osteoinduction occurred in the rat latissimus dorsi muscle flap and depended upon the dose of rhBMP-2. Wrapping rhBMP-2 mixed with atelopeptide type I collagen with the tip of a latissimus dorsi muscle flap could create a prefabricated muscle flap that included bone.

Animals↗

PubMed1998

The blood flow patterns of microsurgical procedures in rats with topical and systemic vasodilators.

The change in blood flow after anastomosis and the effects on the anastomosed artery of different classes of vasodilators such as lidocaine and chlorpromazine given topically (n = 10 in each group), and prostaglandin E1 (PGE1)(n = 12) and diltiazem hydrochloride (n = 10) given systemically, were investigated in the femoral arteries of rats. The blood flow after anastomosis decreased by 45%-60% compared with that before the anastomosis. Lidocaine showed almost the same pattern of blood flow as chlorpromazine. The former dilated the diameter of the vessel less than the latter, and the depression of the heart rate was less with lidocaine than in chlorpromazine. PGE1 had a longer and stronger vasodilatative action than diltiazem, and resulted in a remarkable increase in blood flow. Clinically, the topical application of chlorpromazine or lidocaine is recommended during an operation, and PGE1 should be given systemically after an operation to obtain adequate blood flow.

Administration, Topical↗

PubMed1998

[Mycobacterial lung infection in 8 patients with AIDS: clinical and radiological features].

The prevalence of mycobacterial infection in AIDS patients has increased in Japan. This report describes details of the clinical and radiological features of eight AIDS patients with mycobacterial disease (6 with M. tuberculosis infection and 2 with M. kansasii infection) in our hospital during the period from October 1995 through February 1997. Six of the 8 were men, and two were women. The mean age was 36.5 years. Six were Japanese, one was from Myanmar, and one was Malaysian. The median CD4 positive T lymphocyte counts (CD4 count) at the time of diagnosis of the M. tuberculosis was 75.5 (range 14-569/microliter, and the M. kansasii was 21.5 (range 19-24)/microliter. Clinical findings and symptoms of all patients were non-specific, but almost all patients had a cough and fever. In the radiographic findings, the patients of the M. tuberculosis group presented multiple hilar and mediastinal lymphadenopathy, miliary shadow, and obstructive pneumonia. Both M. kansasii patients showed a multiple infiltration shadow. There were no drug resistant strains in M. tuberculosis except on isolate with moderate resistant. to Streptomycin. These observations suggest that AIDS-associated mycobacterial disease shows atypical clinical and radiological features in some cases, especially in advanced stages of AIDS. Therefore, we need to recognize the characteristics of the clinical and radiological features of the patients with mycobacterial diseases and AIDS.

AIDS-Related Opportunistic Infections↗

PubMed1998

Thieno[2,3-d]pyrimidine-3-acetic acids. A new class of nonpeptide endothelin receptor antagonists.

On the basis of structural information for the cyclic hexapeptide endothelin (ET) receptor antagonist, TAK-044, a series of thieno[2,3-d]pyrimidine-2,4-dione derivatives bearing a carboxyl group and aromatic rings that were important for receptor binding were designed, synthesized, and evaluated for ET receptor binding affinities and inhibitory activities against ET-induced vasoconstriction. Optimization of each substituent in the thieno[2,3-d]pyrimidine ring led to the discovery of a novel and potent nonpeptide ET receptor antagonist, 6-(4-methoxymethoxyphenyl)-5-methylsulfonylaminomethyl-1-(2- methylthiobenzyl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]p yrimidine-3- acetic acid (32 g), which binded to human ETA and ETB receptor subtypes with affinities (IC50) of 7.6 and 100 nM, respectively. Compound 32 g effectively antagonized ET-induced vasoconstriction and the inhibitory effect mediated by the ETB receptor was more potent than that of bosentan, while the inhibitory effect mediated by the ETA receptor was slightly less potent than that of bosentan.

Acetates↗

PubMed1997

Comparison of ectopic osteoinduction in vivo by recombinant human BMP-2 and recombinant Xenopus BMP-4/7 heterodimer.

Two micrograms recombinant human bone morphogenetic protein-2 (rhBMP-2) and 2 microg recombinant Xenopus bone morphogenetic protein-4/7 heterodimer (rxBMP-4/7ht) were implanted into a calf muscle pouch in rats using atelopeptide type I collagen (CL) solution as the carrier. Three weeks later induced bone in the rhBMP-2 + CL group (group A; n=5) and the rxBMP-4/7ht + CL group (group B; n=5) was investigated radiologically and histologically. Bone trabeculum and marrow were induced in all cases of both groups. In group A the area of radioopaque oval shadows was 5.78 mm2, wider than 4.64 mm2 in group B. The radoopacity in group A was 74.6, higher than 57.6 in group B. Histometry of the microscopic views showed that the trabecular area was 0.92 mm2 in group A and 0.22 mm2 in group B, while the trabecular percentage occupied in the overall lump area was 18.07% in group A and 5.51% in group B. The trabecular form in group A was more massively coral than in group B. This study indicated that rhBMP-2 has a higher ectopic osteoinduction ability in vivo than rxBMP-4/7ht.

Animals↗