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Biomedical subjects

H Tada

Publications and source records attributed to H Tada.

At least 271 records · Page 15Linked to original sources
PubMed1994

The antitrust risks of management services organizations, medical foundations, and integrated delivery systems.

This chapter focuses on the antitrust implications of forming a fully integrated delivery system. The danger lies in a challenge by the federal government or private parties, if the proposed system threatens the development of competing systems or excludes individuals or entities. By explaining the risks facing less integrated arrangements involving medical foundations and management services organizations, why forming an integrated system may resolve some of those risks, and the advantages and disadvantages of other options, this chapter also points out one of the primary benefits of forming an integrated system: reducing the antitrust risks. Finally, general suggestions are posed to minimize the antitrust risks when planning and developing any collaborative effort among providers.

Antitrust Laws↗
PubMed1993

Signal sequence trap: a cloning strategy for secreted proteins and type I membrane proteins.

A method was developed to clone, without the use of specific functional assays, complementary DNAs (cDNAs) that carry specific amino-terminal signal sequences, such as those encoding intercellular signal-transducing molecules and receptors. The vector used in this system directed the cell surface expression of interleukin-2 receptor fusion proteins when inserts with signal sequences were cloned in-frame with the correct orientation. An expression cDNA library was constructed from a bone marrow stromal cell line, which contained 5' portion-enriched cDNAs (the average size was 400 base pairs). Two cDNAs that encoded putative cytokine molecules, stromal cell-derived factor-1 alpha (SDF-1 alpha) and SDF-1 beta, which belong to the intercrine-macrophage inflammatory protein superfamily, were cloned.

Amino Acid Sequence↗
PubMed1993

Structure of the Paramecium caudatum gene encoding the B-type of the major hemoglobin component.

We have found the gene (Hb) encoding the B-type of the major hemoglobin (Hb) component in the ciliated protist, Paramecium caudatum, stock K33 of syngen 3. Gene Hb, which encodes a protein consisting of 116 amino acids (aa), had the same sequence as the A-type Hb in this species, with the exception of 10 nucleotides (nt) reflecting 5 single-aa differences. The coding region was interrupted at the position between codons 62 and 63 by one short intron, which was comparable with the second intron of plant Hb in position, phase and nt sequence. The maximum alignment of the P. caudatum Hb aa sequence with the other globin sequences from prokaryotes and lower eukaryotes indicates that these globins can be classified into two groups: one consists of protist and cyanobacterial globins of about 120 aa, and the other consists of fungal and other bacterial globins of about 150 aa having a significant homology with higher eukaryotic Hbs. These proteins share more than 25% homology with one another in each group. Our finding of the P. caudatum Hb intron corresponding to the second intron of plant Hb suggests that all of the globin-encoding genes have a common origin, and that at least two groups had already existed in the globin-encoding gene before prokaryote-eukaryote radiation.

Amino Acid Sequence↗
PubMed1993

Effect of interleukin-6 on cell proliferation of FRTL-5 cells.

We studied the effects of interleukin-6(IL-6) on DNA synthesis and cyclic AMP production in rat thyroid FRTL-5 cells. When cells were incubated with IL-6 in the presence or absence of IGF-I, cell proliferation was not observed. By contrast, IL-6 stimulated DNA synthesis in a dose dependent manner when TSH was added concomitantly. On the other hand, IL-6 did not modulate the cAMP accumulation in the presence or absence of TSH. These data demonstrate that, like IGF-I, IL-6 may be able to act as a growth factor through activation of a mitogenic signal transduction pathway different from A-kinase in FRTL-5 cells.

Animals↗
PubMed1993

Functional regulation of GTP-binding protein coupled to insulin-like growth factor-I receptor by lithium during G1 phase of the rat thyroid cell cycle.

The regulatory effects of lithium on the function of pertussis toxin-sensitive GTP-binding (G(i))-proteins located on the mitogenic pathway activated by insulin-like growth factor-I (IGF-I) in FRTL-5 cells were studied. Addition of GTP-gamma-S to the thyroid stimulating hormone-primed cell membranes resulted in a decreased affinity of IGF-I receptor binding, and the dissociation constant (Kd) increased from 0.46 nM to 3.1 nM. Moreover, IGF-I stimulated GTP-gamma-S binding to a 40-kDa protein, and pertussis toxin (PT) attenuated the stimulatory effect of IGF-I on the same protein. Lithium lowered the affinity of IGF-I receptor binding and the Kd (3.4 nM) was in the same range as that in the presence of GTP-gamma-S. The inhibitory effect of lithium was markedly abolished by pretreatment with PT. Lithium attenuated the amounts of ADP-rebosylation of the 40-kDa protein by PT. In addition, lithium stimulated Ca2+ entry, similar to that by IGF-I, and induced cell proliferation via a PT-sensitive step. These findings suggest that lithium may be capable of modulating the function of G(i)-proteins coupled to IGF-I receptors during the G1 phase of the FRTL-5 cell cycle.

Adenosine Diphosphate Ribose↗
PubMed1993

Genistein, a tyrosine kinase inhibitor, blocks the cell cycle progression but not Ca2+ influx induced by BAY K8644 in FRTL-5 cells.

IGF-I, when added to TSH-primed FRTL-5 cells, induces a long lasting Ca2+ influx and then DNA synthesis. Ca2+ channel agonist, BAYK 8644, is capable to mimic these effects on cell proliferation. We studied the effect of genistein, a specific tyrosine kinase inhibitor, on BAY K8644- or IGF-I- induced cell cycle progression in FRTL-5 cells. Genistein inhibited DNA synthesis induced by BAY K8644 and by IGF-I. In contrast, Ca2+ influx stimulated by BAY K8644 was not inhibited. These data demonstrate that the signal transduction pathway induced by BAY K8644 or IGF-I may possibly involve genistein-sensitive process at the downstream step of Ca2+ entry.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1993

Relationship between urinary excretion of fibronectin degradation products and proteinuria in diabetic patients, and their suppression after continuous subcutaneous heparin infusion.

To explore the possibility that the excretion of urinary fibronectin degradation products (U-FnDP) can be an indicator of the progression of diabetic nephropathy, U-FnDP and urinary protein(U-P) were determined in 64 diabetic patients and 11 healthy volunteers. Moreover, to determine whether continuous subcutaneous heparin infusion (CSHI) reduces elevated U-FnDP and U-P in diabetic patients with persistent proteinuria, heparin sodium was administered as a bolus subcutaneous injection of 5000 IU, followed by subcutaneous infusion of 250 IU/kg per 24 h heparin sodium for 7 days. U-FnDP excretion rate elevated proportionally to the degree of U-P. CSHI reduced significantly elevated U-FnDP from 172.68 +/- 15.79 to 100.04 +/- 14.93 micrograms/24 h (P < 0.01) and U-P from 1.76 +/- 0.13 to 1.20 +/- 0.12 g/24 h (P < 0.01). No significant changes in blood pressure and diurnal mean plasma glucose levels were found. APTT was prolonged with a decrease of AT-III activity during the treatment. These findings suggest that U-FnDP can be one of the indicators which reflects the degree of progression of diabetic nephropathy, and that CSHI may be useful for the normalization of elevated U-FnDP and reduction in U-P in diabetic nephropathy.

Adult↗
PubMed1993

8-methoxypsoralen plus UVA induces the 72 kDa heat shock protein in organ-cultured normal human skin.

The proteins induced by heat and other stressors, called heat shock proteins (HSP) or stress proteins, are considered to play a general role in protection from cellular injury. Exposure to UVA (320-400 nm) following application of 8-methoxypsoralen (8-MOP), termed PUVA is commonly used in the field of dermatology. In order to understand the induction of HSP in PUVA-treated human skin, indirect immunofluorescence using a monoclonal antibody specific for the 72 kDa HSP (HSP 72) was carried out in organ-cultured normal human skin that was treated with PUVA. When the organ-cultured skin was treated at 37 degrees for 1 h with 8-MOP at a final concentration of 10 or 100 micrograms/mL and exposed to UVA (51.3 kJ/m2), nuclear immunofluorescence of HSP 72 was detected in the epidermal cells 12 h after UVA irradiation. In contrast, the induction of HSP 72 was not detected either by UVA irradiation or 8-MOP treatment. These results suggest that PUVA treatment is one of the stressors for human skin, and DNA damage caused by PUVA induces HSP 72.

Aged↗
PubMed1993

Maturational changes of urinary growth hormone excretion in the premature infant.

High plasma GH concentrations are observed in the newborn infant. To characterize the maturational change of GH secretion in premature infants, we serially measured 24-h urinary GH excretion in 30 premature infants. The gestational age ranged from 25-37 weeks and birth weight from 468-2415 g. Urinary GH excretion at 1 week of age was negatively correlated with gestational age, birth weight, and length of infants with adequate intrauterine growth. In the infants with 27 weeks of mean gestation (range, 25-28 weeks) mean urinary GH excretion was highest (6.1 micrograms/day) at the first week, decreased to 1.2 micrograms/day by the fourth week, and remained between 0.05 and 0.18 micrograms/day thereafter. When compared to the corresponding conceptional age, there was no postnatal difference in the pattern of GH excretion between infants with 27 and 31 (range, 29-32) weeks of mean gestational age. Persistent hyperexcretion of GH was observed in 4 of the 5 infants with intrauterine or postnatal growth retardation. Our results suggest that the postnatal change of 24-h urinary GH excretion is similar to ontogenic changes of plasma GH in fetus, and GH may have some effects on postnatal growth in premature infants.

Aging↗
PubMed1993

Interleukin-5 preferentially recruits eosinophils from vessels in nasal mucosa.

Interleukin-5 (IL-5), initially described as possessing eosinophil differentiating and proliferating activity, has now been shown to exert its effects on mature eosinophils. To investigate the ability of recombinant human IL-5 (rhIL-5) to cause the migration of eosinophils in the nasal mucosa in vivo, we compared the eosinophil counts in nasal mucosa without and after the nasal application of rhIL-5. In addition, the percentages of eosinophils in leukocytes within the vascular lumens in the nasal mucosa were counted to determine whether IL-5 recruited eosinophils from the vessels. The total number of eosinophils in both the epithelium and lamina propria, as well as the percentage of eosinophils in leukocytes within the lumens of vessels in the nasal mucosa after the application of IL-5, were higher than those in control nasal mucosa. Conversely, neither the number of neutrophils in the nasal mucosa nor the percentages of neutrophils in vessels differed between the two groups of nasal mucosa. The results strongly suggest that IL-5 preferentially recruits eosinophils from vessels into the lamina propria.

Adult↗
PubMed1993

Effects of pravastatin on lipid transfer protein and lecithin cholesterol acyltransferase in heterozygous familial hypercholesterolemia.

The effects of HMG CoA reductase inhibitor PRAVASTATIN on plasma lipoprotein levels, lipid transfer protein (LTP) activity and lecithin cholesterol acyltransferase (LCAT) activity were investigated in 20 patients with heterozygous familial hypercholesterolemia. Plasma total cholesterol decreased from 299.2 +/- 45.2 to 245.9 +/- 45.1 (mean +/- SD in mg/dl) (p < 0.0001), low density lipoprotein (LDL) cholesterol from 221.1 +/- 47.6 to 164.9 +/- 48.1 (p < 0.0001) and LDL-triglycerides from 38.0 +/- 10.2 to 30.2 +/- 8.8 (p < 0.0001). High density lipoprotein (HDL) cholesterol increased from 60.1 +/- 13.9 to 63.1 +/- 17.0 (p = 0.0264). The HDL-cholesterol: HDL-triglycerides ratio increased from 3.91 +/- 1.14 to 4.91 +/- 1.65 (p = 0.0029). Lipid transfer protein (LTP) activity (as % of transferred cholesteryl ester (CE)) decreased from 4.68 +/- 2.47 to 3.70 +/- 2.31 (p = 0.0024) and LCAT activity decreased from 113.1 +/- 29.9 (U/L) to 97.0 +/- 22.7. There was a negative correlation between LTP/LCAT ratio and HDL-C levels. These results suggested that the changes in plasma HDL-cholesterol concentrations during treatment with pravastatin may be related to the decreases in LTP and LCAT activity due to this drug.

Adult↗
PubMed1993

[Alterations of skeletal muscle metabolism in patients with congestive heart failure].

The metabolism of the skeletal muscles during exercise and recovery was investigated using phosphocreatinine (PCr) and inorganic phosphate (Pi) in patients with chronic heart failure. PCr/Pi ratio, which is closely related to the ATP/ADP ratio, and the pH were measured by 31P-magnetic resonance spectroscopy (31P-MRS) during and after forearm exercise in 9 patients with chronic heart failure, 11 patients with chronic lung disease, and 8 normal subjects. Exercise and recovery scans were recorded every minute for 4 min. The PCr/Pi ratio in patients was lower during the recovery period and significantly lower 3 and 4 min after exercise than in normal subjects. The pH values after exercise were lower in patients, although not significantly. The PCr/Pi ratio 4 min after exercise in patients was not correlated with parameters of cardiac function or arterial and mixed venous oxygen tension. Nutritional parameters did not vary statistically among the groups. Metabolic abnormalities may be present in the skeletal muscles of patients' group, which are not due to undernutrition, possibly as a result of exercise deconditioning and probably a shift in fiber distribution (type I decreases, type IIb increases) and a decrease in oxidative capacity.

Aged↗
PubMed1993

[Serum level of soluble ICAM-1 in subjects with nasal allergy and ICAM-1 mRNA expression in nasal mucosa].

Intercellular adhesion molecule-1 (ICAM-1) has been reported to be instrumental in airway eosinophils and airway hyperreactivity. In nasal mucosa, ICAM-1 molecule is observed on the endothelium, around the nasal gland and just below the epithelium. In this study, we investigated the gene expression of ICAM-1 in nasal mucosa and the serum level of soluble ICAM-1. In subjects with nasal allergy sensitized with house dust, a pair of house dust antigen discs were placed on the inferior nasal mucosa on one side, while control discs free of antigen were placed on the other side. After six hours, the inferior nasal mucosa were bilaterally obtained separately. By Southern blot analysis following a reverse-transcription polymerase chain reaction, we detected ICAM-1 messenger RNA (mRNA) in the nasal mucosa. Although the expression of ICAM-1 mRNA was already observed in the nasal mucosa without antigen challenge, it increased six hours after the challenge. The serum level of immunoreactive soluble ICAM-1 in the subjects with nasal allergy and normal subjects was evaluated by sandwich enzyme-linked immunosorbent assay. The serum level of soluble ICAM-1 in the subjects with nasal allergy was 380.7 +/- 105.2 ng/ml. It was significantly higher than that of the normal control, which was 278.6 +/- 64.6 ng/ml. These results suggested that the increased expression of ICAM-1 may contribute to the pathogenesis of nasal allergy by facilitating the infiltration of inflammatory cells such as eosinophils and their functional activities.

Adolescent↗
PubMed1993

[Thrombospondin modulates cell attachment, spreading and proliferation in cultured rat mesangial cells].

The effect of thrombospondin (TSP) on attachment, spreading, cell toxicity and proliferation of cultured rat mesangial cells (M cell) were investigated. The results are as follows: 1. Attachment and spreading of M cell on the culture plates coated with TSP were inhibited in a dose dependent manner, 2. 50 micrograms/ml TSP in the medium brought about the significant detachment of the adhered M cell. 3. TSP had no demonstrable effects on 51Cr-release from M cell, 4. 3H-thymidine uptake into M cell was inhibited by TSP in a dose dependent manner. These results indicate that TSP modulates attachment, spreading and proliferation of M cell. Therefore, it is suggested that overproduction of TSP in M cell under some pathophysiologic conditions such as diabetic nephropathy may influence the M cell functions in a self-suppression.

Animals↗
PubMed1992

Induction and repair of UVB-induced cyclobutane pyrimidine dimers and (6-4) photoproducts in organ-cultured normal human skin.

To examine the induction and repair of UV-induced DNA damage, indirect immunofluorescence was performed on UVB-irradiated organ-cultured normal human skin using monoclonal antibodies specific for either cyclobutane pyrimidine dimers or (6-4) photoproducts. Nuclear immunofluorescence of cyclobutane pyrimidine dimers and (6-4) photoproducts were observed in a dose-dependent manner after UVB irradiation. The intensity of nuclear immunofluorescence of the upper epidermal layers was stronger and clearer than that of the lower epidermal layers. DNA repair time-course studies showed that both types of DNA damage could be repaired within 24 h after UVB irradiation.

Cyclobutanes↗
PubMed1992

The effect of recombinant human interleukin-5 on eosinophil accumulation and degranulation in human nasal mucosa.

Recombinant human interleukin-5 (rhIL-5) was administered repeatedly onto the nasal mucosa of individuals with Japanese cedar pollinosis outside the pollen season. The numbers of eosinophils and epithelial cells and the amount of eosinophil cationic protein (ECP), secretory IgA (S-IgA), and IgA in the nasal lavage fluid increased significantly after the application of rhIL-5. Responsiveness to histamine was also enhanced after the application. When S-IgA was administered onto the nasal mucosa after application of rhIL-5, the amount of ECP in the nasal lavage fluid was significantly more increased. The above findings together with the facts that IL-5 promotes production of IgA, that IgA receptors are present on eosinophils, and that rhIL-5 does not increase release of ECP from eosinophils isolated from the peripheral blood suggest that a series of possible reactions consisting of (1) IL-5--induced production of IgA from the immune-mediating cells, (2) binding of secretory components released from either serous glandular cells or epithelial cells of the nasal mucosa with IgA, (3) release of ECP from eosinophils induced by S-IgA and/or IgA, (4) epithelial damage to the nasal mucosa, and (5) development of nasal hyperreactivity to histamine.

Adult↗