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Biomedical subjects

M Iwamoto

Publications and source records attributed to M Iwamoto.

At least 127 records · Page 7Linked to original sources

Culture of stromal cells derived from medullary cavity of human long bone in the presence of 1,25-dihydroxyvitamin D3, recombinant human bone morphogenetic protein-2, or ipriflavone.

We previously showed that stromal cells derived from bone marrow specimens formed at the fracture site of human long bone differentiated during culture to polygonal cells and spindle cells, and polygonal cells, but not spindle cells, produced calcified matrix. To clarify the origin of polygonal and/or spindle cells, and factors necessary for differentiation of marrow stromal cells to osteogenic cells, we cultured stromal cells derived from the normal (unfractured) medullary cavity (SCN) as well as stromal cells from the medullary cavity distant from the fracture site (SCF). After 3 weeks of primary culture and 2 days of secondary culture, the cells were cultured in medium containing 1,25-dihydroxyvitamin D3 (VD), recombinant human bone morphogenetic protein-2 (BMP), or ipriflavone (IF) for 3 weeks. For biochemical analysis, cells reaching confluence after 3 weeks of secondary culture were cultured with one of the factors for 3 days. Some of SCF cultured with VD or IF were transformed to polygonal cells, and showed high alkaline phosphatase (ALPase) activity and high osteocalcin and insoluble calcium production. Cloned polygonal cells from the SCF formed nodules and aggregates consisting of calcium. Other SCF cultured with VD or IF and SCF cultured with BMP were spindle shaped. Some spindle-shaped cells from SCF cultured with BMP or IF revealed high ALPase activity and high osteocalcin production, comparable with the spindle cells from the fracture site. However, spindle-shaped cells from SCF cultured with VD and other spindle-shaped cells from SCF cultured with BMP or IF showed low ALPase activity and low osteocalcin production. The results show that SCF probably contain at least three subpopulations: (a) cells that differentiate to polygonal cells by the influence of VD or IF; (b) cells that differentiate to the spindle cells by the influence of BMP or IF; and (c) cells that are not transformed by the influence of VD, BMP, or IF.

Adolescent↗

Prolonged use of intradialysis parenteral nutrition in elderly malnourished chronic haemodialysis patients.

BACKGROUND: The treatment of malnutrition, frequently present in elderly dialysis patients, is important to promote better quality of life and rehabilitation. The aim of this study was to assess the impact of prolonged use of intradialysis parenteral nutrition (IDPN) as a strategy for malnutrition in elderly haemodialysis patients. METHODS: Twenty-eight elderly patients (non-diabetic, age over 70) on chronic haemodialysis for at least 2 years were evaluated. Ten consenting patients were treated with IDPN containing glucose, essential amino acids, and lipid emulsion during the course of regularly scheduled dialysis treatments for approximately 1 year. Nutritional evaluation using seven parameters (anthropometric measurements such as body mass index, triceps skinfold thickness, mid-arm circumference, mid-arm muscle circumference, and albumin, transferrin, and total lymphocyte count) was performed at various intervals on patients with IDPN and 18 patients without IDPN. The plasma amino-acid profile and dietary protein calorie intake were also determined. RESULTS: In patients receiving IDPN, significant increases in serum albumin and transferrin concentrations and total lymphocyte count in peripheral blood smears paralleled increases in protein-calorie intake beginning after 3 months of treatment and remained favourable throughout the study period. Anthropometric data started to improve significantly after 6 months of treatment. Patients without IDPN had gradual decreases in all parameters during the study period. A significant increase in essential amino acids and a significant decrease in 3-methyl-histidine were observed in patients with IDPN and a further decrease in essential amino acids was observed in patients without IDPN. CONCLUSION: Prolonged use of IDPN prevents muscle protein catabolism and promotes body protein and fat accumulation. IDPN appears to be effective in malnourished elderly haemodialysis patients.

Aged↗

V108M mutant of pharaonis phoborhodopsin: substitution caused no absorption change but affected its M-state.

Crystallographic data reveal that Met-118 in bacteriorhodopsin (bR) contacts directly with the C9 methyl group of retinal, and Khorana et al. [J. Biol. Chem. 268, 20305-20311 (1993)] suggest that this contact may regulate the absorption maximum (lambdamax). We have replaced the amino acid (Val-108) corresponding to Met-118 of bR by methionine in pharaonis phoborhodopsin (ppR), whose lambdamax is ca. 500 nm, while those of other bacterial rhodopsins such as bR, halorhodopsin, and sensory rhodopsin are red-shifted by 60-90 nm. By flash-photolysis measurement, we could not recognize a large spectral red-shift of the V108M mutant. On the other hand, the decay of ppRM (M-intermediate) of the mutant was approximately three times as fast as that of wild-type, and an M-like intermediate (M') whose lambdamax is blue-shifted by 60 nm from that of M became appreciable. The replacement abolished the shoulder of the ppRM spectrum. From these findings, we infer that the distance between the retinal and the 108-position in ppR is relatively long, and that in the M-state this distance is shortened.

Amino Acid Sequence↗

Developmental role of PTHrP in murine molars.

Although PTHrP is produced in multiple fetal tissues, its precise physiological functions have yet to be clearly elucidated. The present study was undertaken to elucidate the biological role of PTHrP in the development of tooth. In rat tooth germs, the PTHrP and its receptor genes were expressed in the enamel organ and dental mesenchyme, respectively. When mouse tooth explants were cultured with antisense oligodeoxyribonucleotides (ODN) against mouse PTHrP mRNA in serum-free medium, an invasion of bone tissue was observed in the tooth germs. On the other hand, the explants cultured without ODN or with sense ODN showed normal histological structures similar to those observed in vivo. These results suggest that PTHrP is essential for tooth development and for the protection of tooth germs from the invasion of bone tissue.

Animals↗

Does prolonged exercise alter diet-induced thermogenesis?

Diet-induced thermogenesis (DIT) is mainly an insulin-mediated response and the result of fat and glycogen synthesis. We investigated DIT at rest and after exercise to clarify the mechanism of exercise-induced changes in DIT in 6 healthy men (mean age 36 +/- 16 years). Subjects exercised for 1 h at 58% of maximal O2 consumption on a bicycle ergometer and then rested for 8 h sitting in a comfortable chair (exercise experiment). On a different day, subjects rested for 8 h without preceding exercising (non-exercise experiment). At 12.30 h, the subjects were given their second meal. DIT to individual meal did not differ significantly between the exercise and non-exercise days. Increased insulin sensitivity and increased free fatty acid oxidation by exercise may facilitate the conversion of glucose to glycogen in muscle. On the other hand, insulin secretion expressed as the ratio of plasma levels of insulin to glucose after the meal was significantly decreased in the exercise experiment (p < 0.05). Study of heart rate variability showed that sympathetic tone, a primary hormonal determinant of glucose metabolism during exercise, was increased and parasympathetic tone was decreased during the recovery period in the exercise experiment (p < 0.05). These findings suggest that changes in DIT are affected by many factors and may be related to the balance between these counteracting factors.

Adult↗

A case of anaphylactoid purpura with multiple blister formation: possible pathophysiological role of gelatinase (MMP-9).

A 10-year-old Japanese male with multiple blister formation and palpable purpura in the course of anaphylactoid purpura is described. Histologically, the lesions showed leukocytoclastic vasculitis in the upper dermis with subepidermal clefts. Blister fluid showed matrix metalloproteinase (MMP) 2 and MMP-9 gelantinolytic activities using zymography. These enzymatic reactions, especially that involving MMP-9 derived from polymorphonuclear leukocytes, might play an important role in the pathophysiology of this condition.

Blister↗

Review on the physical growth in primates.

J.M. Tanner concluded in 1962 that the growth velocity curve in body weight shows two peaks in primates but only one peak in the other mammals, and that the first peak in primates corresponds phylogenetically to the peak in the other mammals. Many reports on the physical growth of primates have been accumulated in the past 70 years. Using some of them as a basis, the author illustrated the normative velocity curves (increment curves) of the weight of monkeys, chimpanzees and humans, and reconsidered Tanner's conclusion. However, there are still some as yet obscure aspects to be interpreted in future.

Aging↗

Effects of room temperature, seasonal condition and food intake on finger skin temperature during cold exposure test for diagnosing hand-arm vibration syndrome.

For diagnosing the hand-arm vibration syndrome, peripheral circulation and sensory tests immersing one hand in cold water at 10 degrees C for 10 min have been performed widely in Japan. The authors investigated the effects of room temperature, seasonal condition and food intake on the test results, especially finger skin temperature. Six healthy males were examined repeatedly under six different room temperatures at 10 degrees C, 15 degrees C, 20 degrees C, 22.5 degrees C, 25 degrees C and 30 degrees C. Eight healthy males were examined under room temperatures at 10 degrees C, 20 degrees C and 30 degrees C, repeatedly in winter, spring, summer and autumn. Six healthy males were examined in summer under room temperature at 22.5 degrees C repeatedly 1 hr after, 3 hr after meal and after fasting for 13 hr. The finger skin temperature was strongly affected by room temperature. The finger skin temperature was also affected by seasonal condition. No remarkable effect of food intake was observed. For estimating circulatory function of the upper extremities using the finger skin temperature, the room temperature should be strictly controlled and the effect of seasonal condition must be taken into consideration.

Adult↗

[A case of unresectable advanced gastric cancer with severe obstructive jaundice responding to combined chemotherapy with 5-fluorouracil and low-dose cisplatin].

A 69-year-old male patient with gastric cancer complaining severe jaundice was readmitted for the purpose of chemotherapy. The primary tumor was unresectable, and his jaundice was gradually increasing because of the growth of tumor, so the patient was treated by combined chemotherapy with 5-fluorouracil and low-dose cisplatin for 2 courses (1 course = 4 weeks), which resulted in remarkable reduction of jaundice without any severe side effects. So, the patient could be discharged and spend a useful life for about 10 months with good quality of life. This therapy might be a useful palliative chemotherapy for cases of this kind.

Aged↗

A close temporal relationship of liver disease to antiribosomal P0 protein antibodies and central nervous system disease in patients with systemic lupus erythematosus.

OBJECTIVE: To determine whether there is a close temporal relationship of liver disease to serum IgG and/or IgM antiribosomal P0 protein antibodies (anti-P0) and central nervous system (CNS) lupus in patients with systemic lupus erythematosus (SLE). METHODS: The study included 70 patients with active SLE. Of these, 30 had IgG and/or IgM anti-P0 and 14 had CNS lupus other than psychiatric disease (nonpsychiatric CNS lupus). Of these 14 patients, 11 had anti-P0. Laboratory manifestations of liver disease were retrospectively analyzed. RESULTS: Liver disease not attributed to any cause other than SLE (SLE liver disease) was present in 8 of the 11 patients with anti-P0 with nonpsychiatric CNS lupus (72.7%), in none of the 19 patients with anti-P0 without nonpsychiatric CNS lupus (0%), and in one of the 40 patients without anti-P0 (2.5%). The prevalence of SLE liver disease was significantly greater in patients with anti-P0 with nonpsychiatric CNS lupus than in the other 2 groups (p < 0.0001). Mean levels of liver enzymes (lactate dehydrogenase, glutamic oxaloacetic transaminase, glutamate pyruvate transaminase, gammaglutamyl transpeptidase) were significantly higher in patients with anti-P0 with nonpsychiatric CNS lupus than in the other 2 groups. Serial studies in 3 patients showed that the appearance of anti-P0 and liver dysfunction slightly preceded the onset of nonpsychiatric CNS lupus. CONCLUSION: Anti-P0 may be related to the pathogenesis of CNS lupus and SLE liver disease found simultaneously in SLE. The appearance of anti-P0 and liver dysfunction may predict onset of CNS lupus.

Adolescent↗

[Clinical evaluation as palliative therapy of combination chemotherapy with continuous infusional 5-fluorouracil and consecutive low-dose cisplatin in unresectable gastrointestinal carcinoma].

Combination chemotherapy with continuous infusion 5-FU, 350 mg/m2/day and low-dose CDDP between 5 to 10 mg/body/day (day 1-5) was evaluated in 46 patients with unresectable gastric (34), colorectal (10) and biliary tract (2) carcinoma. This regimen was repeated for 4 weeks. The overall response rate was 45.7% (21/46), but the resectable rate was only 10.9% (5/46). Toxic response (> grade 2) was 22% (10/46). After chemotherapy, the patients preserved good performance status and quality of life. Median survival time was about 11 months, and there was no significant difference between CR or PR cases and NC one. Survival time of patients correlated not to the reduction rate of tumor but to conditions of hosts (e.g., performance status, quality of life). These results suggested that this therapy is an effective palliative chemotherapy for patients with unresectable gastrointestinal carcinoma.

Adult↗

Role of the major histocompatibility complex class II Ea gene in lupus susceptibility in mice.

The gene(s) encoded within major histocompatibility complex (MHC) act as one of the major genetic elements contributing to the susceptibility of murine systemic lupus erythematosus (SLE). We have recently demonstrated that lupus susceptibility is more closely linked to the I-E- H-2(b) haplotype than to the I-E+ H-2(d) haplotype in lupus-prone BXSB and (NZB x BXSB)F1 hybrid mice. To investigate whether the reduced susceptibility to SLE in H-2(d) mice is related to the expression of the MHC class II Ea gene (absent in H-2(b) mice), we determined the possible role of the Ea gene as a lupus protective gene in mice. Our results showed that (i) the development of SLE was almost completely prevented in BXSB (H-2(b)) mice expressing two copies of the Ead transgene at the homozygous level as well as in BXSB H-2(k) (I-E+) congenic mice as for H-2(d) BXSB mice, and (ii) the expression of two functional Ea (transgenic and endogenous) genes in either H-2(d/b) (NZB x BXSB)F1 or H-2(k/b) (MRL x BXSB)F1 mice provided protection from SLE at levels comparable to those conferred by the H-2(d/d) or H-2(k/k) haplotype. In addition, the level of the Ea gene-mediated protection appeared to be dependent on the genetic susceptibility to SLE in individual lupus-prone mice. Our results indicate that the reduced susceptibility associated with the I-E+ H-2(d) and H-2(k) haplotypes (versus the I-E- H-2(b) haplotype) is largely, if not all, contributed by the apparent autoimmune suppressive effect of the Ea gene, independently of the expression of the I-A or other MHC-linked genes.

Animals↗

Functional expression of pharaonis phoborhodopsin in Escherichia coli.

Pharaonis phoborhodopsin, the photoreceptor of the negative phototaxis of archaebacterial Natronobacterium pharaonis, was functionally expressed in the heterologous system of Escherichia coli. Flash-photolysis on a millisecond time scale indicated that the photochemical properties of ppR expressed in E. coli were the same as those of the native ppR in N. pharaonis. We concluded that the integral membrane protein ppR is correctly folded in vivo in the eubacterial E. coli membrane.

Archaeal Proteins↗

Maxwell Displacement Current across Langmuir Phospholipid Monolayers Mixed with Azobenzene by Photoisomerization

Mixed monolayers composed of phospholipid and fatty acid containing azobenzene on a water surface were investigated by the Maxwell displacement current (MDC) measurement method. The transient displacement current pulses were generated across mixed monolayers due to the photoisomerization of fatty acid containing azobenzene by alternating irradiation of ultraviolet and visible light because the condensation of pure azobenzene monolayers was loosened by the introduction of phospholipids into the monolayers. The charge flow and Maxwell displacement currents generated during light irradiation were also investigated in connection with monolayer compression cycles. It was found that MDC pulses were generated over the entire range of molecular area, and the maximum of MDC appeared at the molecular area just before the initial rise of surface pressure in both first and second compression cycles, although the surface pressure-area isotherm of the mixed monolayers gives a shift with respect to the molecule-area axis with the cyclic application of monolayer compression. Copyright 1997Academic Press

Journal Article↗

Induction of osteogenic differentiation by hedgehog proteins.

In this study we asked whether members of the hedgehog gene family are involved in osteogenesis. C3H10T1/2 cells and MC3T3-E1 cells expressed the putative hedgehog receptor patched (Ptc) gene. Medium conditioned by chicken embryo fibroblast cultures expressing either Indian hedgehog or Sonic hedgehog stimulated alkaline phosphatase (APase) activity in cultures of the mouse mesenchymal cell line C3H10T1/2 and the osteoblastic cell line MC3T3-E1. These stimulatory effects were synergistically enhanced by bone morphogenetic protein-2 (BMP-2). Treatment with the amino-terminal portion of recombinant Sonic hedgehog proteins (rShh-N) up-regulated the expression of the Ptc gene within 12 h and increased production of APase in C3H10T1/2. rShh-N and BMP-2 also synergistically stimulated APase activity. rShh-N treatment did not affect the expression levels of Bmp-2, -4, -5, -6 and -7 genes. These findings indicate that hedgehog proteins directly act on osteogenic precursor cells and osteoblasts and stimulate osteogenic differentiation of these cells in co-operation with BMPs.

3T3 Cells↗