Search PubMed⌕ Search

Biomedical subjects

T Kuroda

Publications and source records attributed to T Kuroda.

At least 163 records · Page 9Linked to original sources
PubMed1997

Basic fibroblast growth factor induces apoptosis in myofibroblastic cells isolated from rat palatal mucosa.

The effect of basic fibroblast growth factor (bFGF) on apoptosis in normal rat palatal fibroblasts and rat palatal scar fibroblasts was examined by the TUNEL method in order to clarify the mechanism of apoptosis induction in myofibroblasts during the scar formation process. A percentage of scar fibroblasts undergoing apoptosis was significantly higher than that of palatal fibroblasts when they were treated with bFGF succeeding to serum starvation. Palatal fibroblasts, phenotypically modulated into myofibroblasts by the pretreatment with transforming growth factor-beta 1 (TGF-beta 1), similarly showed a higher level of apoptosis induction by bFGF-treatment. TGF-beta 1 elevated protein and mRNA level of FGF receptor (FGFR) in palatal fibroblasts. Tyrosine autophosphorylation of FGFR upon stimulation by bFGF was significantly higher in scar fibroblasts than in normal palatal fibroblasts. These findings suggested that bFGF may be a potential stimulator of apoptosis in myofibroblasts during palatal scar formation and that FGFR may be responsible for this process.

Animals↗
PubMed1997

Hepatoma-derived growth factor belongs to a gene family in mice showing significant homology in the amino terminus.

Hepatoma-derived growth factor (HDGF) is an acidic polypeptide with mitogenic activity for fibroblasts performed outside the cells despite the presence of a putative nuclear localization signal (NLS). We have now cloned three related mouse cDNAs: one for a mouse homologue of human HDGF and two for additional HDGF-related proteins provisionally designated HDGF-related proteins 1 and 2 (HRP-1 and -2). Their deduced sequences have revealed that HDGF belongs to a new gene family with a highly conserved 98-amino-acid sequence at the amino terminus (hath region, for homologous to the amino terminus of HDGF). HRP-1 and HRP-2 proteins are 46 and 432 amino acids longer than mouse HDGF, respectively, and have no conserved amino acid sequence other than the hath region. HRP-1 is a highly acidic protein (26% acidic) and also has a putative NLS. HRP-2 protein carries a mixed charge cluster, a sharp switch of positive-to negative-charge residues, which is often found in some nuclear proteins. Northern blotting shows that mouse HDGF and HRP-2 are expressed predominantly in testis and skeletal muscle, to intermediate extents in heart, brain, lung, liver, and kidney, and to a minimal extent in spleen. HRP-1 is expressed specifically in testis. These findings suggest that the HDGF gene family might play a new role in the nucleus especially in testis.

Amino Acid Sequence↗
PubMed1997

Transforming growth factor-beta 1 modulates myofibroblastic phenotype of rat palatal fibroblasts in vitro.

The effects of transforming growth factor-beta 1 (TGF-beta 1) on normal rat palatal fibroblasts in vitro were investigated in the present study in order to unravel the precise mechanisms by which the phenotypic modulation of fibroblasts occurs during the scar formation process. TGF-beta 1 dramatically changed the morphology of normal palatal fibroblasts from polygonal into an elongated shape, which was very similar to that of fibroblasts derived from experimental immature scar tissue in rat palatal mucosa. This morphological transition was concomitant with an increase in the expression of alpha-smooth muscle (alpha-SM) actin protein, a marker for myofibroblasts, when determined by immunocytochemistry. An immunoblot study also revealed that alpha-SM actin expression in palatal fibroblasts became evident after 24 h of TGF-beta 1 treatment and increased time-dependently up to 72 h. Northern blot analysis showed that TGF-beta 1 stimulated endogenous TGF-beta 1 mRNA expression in palatal fibroblasts within 24 h. Neither epidermal growth factor nor basic fibroblast growth factor had any effect on either alpha-SM actin expression or TGF-beta 1 mRNA expression. Pretreatment of palatal fibroblasts with TGF-beta 1 significantly increased the contractile capacity in a three-dimensional collagen gel culture, even when the culture medium was deprived of TGF-beta 1 for 72 h of the experimental period. Moreover, the contractility of scar fibroblasts, which highly expressed alpha-SM actin protein and TGF-beta 1 mRNA, was significantly lowered by a neutralizing antibody to TGF-beta 1. These data strongly suggest that TGF-beta 1 is a potential inducer of phenotypic expression of myofibroblasts in palatal fibroblasts and that auto-induction of TGF-beta 1 mRNA expression may play an important role in the scar formation process in palatal mucosa.

Actins↗
PubMed1997

Osteogenic cell cytotoxicity and biomechanical strength of the new ceramic Diopside.

Diopside was prepared by sintering a powder compact composed of CaMgSi2O6 at 1573K for 2 h. In order to clarify the biocompatibility of Diopside, the cytotoxicity of Diopside against the osteogenic cell line MC3T3-E1 and the bone-Diopside interface strength were examined. On both the 14th and 21st days of incubation of MC3T3-E1 cells with Diopside, ALP activities were not significantly lower than those of the CTRL. TEM photographs of MC3T3-E1 on Diopside after 14 days of incubation showed active secretion of crystals from osteoblast-like cells. Scanning electron microscopic analysis showed that the cells on Diopside formed multiple cell layers similar to those on the CTRL both 14 and 21 days after incubation. These results showed that Diopside had no cytotoxic effect on MC3T3-E1. The pulling test showed that failure loads of Diopside were significantly lower than those of AWGC. Histologically, there was no fibrous tissue or foreign body reaction at the bone interface. SEM-EPMA showed that Diopside had attached to the bone via a calcium-phosphorus layer. SEM back-scattered electron imaging showed that the Diopside plate had degraded to a porous state 12 weeks after implantation. These findings indicate that Diopside is a biodegradable ceramic.

3T3 Cells↗
PubMed1997

Cardiac abnormalities and cytosine-thymine-guanine trinucleotide repeats in myotonic dystrophy.

This study investigated the correlation between cardiac abnormalities and cytosine-thymine-guanine (CTG) trinucleotide repeat expansion in patients with myotonic dystrophy (MD). We studied 18 patients with the adult form of classical MD and 18 age-matched control subjects. In patients with MD, left ventricular systolic function at rest was not different from that in normal subjects. On the other hand, of Doppler parameters of diastolic function, mitral inflow peak early velocity and atrial velocity were significantly lower, and deceleration time and isovolumic relaxation time were significantly longer in patients with MD compared with normal controls. No significant correlation was observed between these diastolic parameters and CTG repeat expansion in the patients, although the parameters showed a positive correlation with age and neurologic symptom duration. Electrocardiographic conduction abnormalities were detected in 42% of patients. These patients showed a significantly longer symptom duration, although the size of CTG repeats was not different between the patients with and without conduction abnormalities. This study demonstrated that, in patients with MD, significant alterations in ventricular diastolic function (myocardial myotonia) occur in addition to conduction abnormalities. The size of CTG expansion is not a predictor of these cardiac involvements.

Adult↗
PubMed1997

Hanshin-Awaji earthquake as a trigger for acute myocardial infarction.

On Jan. 17, 1995, the Hanshin-Awaji district was struck by the most destructive earthquake ever to occur in Japan. It is commonly believed that acute emotional stress such as that caused by an earthquake can trigger acute myocardial infarction (AMI). The objective of this study was to evaluate the effect of the quake stress on the onset of AMI in our district. The number of patients with AMI during the first 4 weeks after the quake increased by about 3.5-fold. The mean age of patients was 72.5 +/- 2.8 years, and the proportion of women (53%) was significantly greater than in the preceding years. The proportion of patients without prodromal angina pectoris was 53%. The mean post-traumatic stress disorder reaction index score (n = 14) was 40.1 +/- 4.1, which indicates a severe stress level. The mean score in the women (45.9 +/- 4.7; n = 7) was significantly higher than that in the men (34.3 +/- 6.4; n = 7). We concluded that after an earthquake, severe emotional stress can trigger AMI, more often than normal in women.

Aged↗
PubMed1997

Immunohistochemical localization of parathyroid hormone-related protein in developing mouse Meckel's cartilage and mandible.

In order to clarify the role of parathyroid hormone-related protein (PTHrP) during Meckel's cartilage and mandibular development, an immunohistochemical study of PTHrP and its receptor, PTH/PTHrP receptor, was designed to examine their localization in the anterior region of Meckel's cartilage including the rostrum, which is known to contribute to the development of the mandible. Meckel's cartilage was first observed on day 13 of gestation and PTHrP was faintly localized in the chondrocytes. On day 16 of gestation, at the stage of elongation and initiation of endochondral ossification in Meckel's cartilage, PTHrP was localized in the chondrocytes located in the area showing interstitial growth and in and around the nuclei of hypertrophic chondrocytes undergoing endochondral ossification. At day 18 of gestation, endochondral ossification was spread over the entire area proximal to the molar region in Meckel's cartilage, except in the mesial fusion site formed by immature chondrocytes. PTHrP was localized in the osteoblasts adjacent to the calcified matrix, but had disappeared from the chondrocytes forming Meckel's cartilage. The localization of PTH/PTHrP receptor was similar to that of PTHrP. These results show that localization of PTHrP is spatially and temporally related to the growth of Meckel's cartilage.

Animals↗
PubMed1997

Clinical application of minimal residual neuroblastoma cell detection by reverse transcriptase-polymerase chain reaction.

The highly sensitive method to detect neuroblastoma (NB) cells using reverse transcriptase polymerase chain reaction (RT-PCR) was applied in the practical clinics, and its efficacy was assessed in the present study. Human tyrosine hydroxylase (TH), a rate-limiting enzyme in the catecholamine biosynthesis, was used as the marker for NB cells, and the expression of THmRNA was examined in 13 samples (four peripheral blood and nine bone marrow) harvested from seven patients (four with stage IV, one with stage III, two with stage II) using RT-PCR with our original primers. The positive signals for NB cells were detected in four samples (one peripheral blood and three bone marrow) by the PCR method, but were undetectable by the conventional histological examinations. In the present series, a case that showed a positive signal for NB cells in the peripheral blood showed a remarkably unfavorable clinical course, indicating that the circulating NB cells detected by the PCR method can be a sign of the progressively advanced NB, and may define a new prognostic factor suggesting higher risk. In another case, the PCR detection for the residual NB cells in the bone marrow provided important supporting evidence to determine the necessity of the additional chemotherapy and the suitable timing for bone marrow transplantation. This detection also guaranteed the safety of the bone marrow for transplantation. The PCR method was considered to be very beneficial in the selected cases. However, some problems such as the false-negative results in the negative urinary vanillylmandelic acid secretor were also highlighted in the present study.

3-Iodobenzylguanidine↗
PubMed1997

Hypernatremic suppression of neutrophils.

Phagocytic and bactericidal activities are important functions of the human polymorphonuclear leucocytes (PMNL) as the host defence against burn wound infection. The zone of stasis, just below the zone of coagulation, is a site of interaction between invading bacteria and PMNL. For many reasons the osmotic pressure at this site is elevated. In this study we evaluated the in vitro phagocytic and bactericidal activities of PMNL under hypernatremic conditions. At a sodium concentration of 180 mEq/l, phagocytic activity was suppressed. Although on average superoxide production was maintained within the normal range, it was suppressed in three of the ten cases studied. We conclude that the hypernatremic condition may weaken local defence against burn wound infection at the zone of stasis and may be a risk factor for burn wound sepsis.

Burns↗
PubMed1997

Hypernatremia deepens the demarcating borderline of leukocytic infiltration in the burn wound.

The influence of hypernatremia on progressive burn wound necrosis was evaluated in a second-degree burn model. The depth of the burned tissue sloughed off was measured in a comparative study in the rat (contact burn injury with a metal plate, 70 degrees C for 5 s). Rats in the hypernatremic group were treated with an intraperitoneal fluid injection of hypernatremic saline (10 ml, 850 mEq/l). Control rats were injected with hyponatremic saline (10 ml, 100 mEq/l). On the fourth postburn day specimens were harvested and compared. The greatest depth of leukocytic infiltration (percent of total dermal thickness) was measured. The average depths were significantly different. In zone 1 (from the normal skin edge to 5 mm inside the wound) the average depth in the hypernatremic group was 38.0 +/- 9.3 percent of the dermal depth and in the control group 9.5 +/- 1.2 percent. In zone II (from 5 to 10 mm inside the wound) the hypernatremic group sloughed off at 64.0 +/- 11.8 percent and the control group at 12.5 +/- 2.1 percent. The hypernatremic group showed a deeper demarcating borderline of leukocytic infiltration than the control rats. The wound depth progression may be caused by an osmotic injury.

Animals↗
PubMed1997

A sensitive and selective method for the determination of mevalonic acid in dog plasma by gas chromatography/negative ion chemical ionization-mass spectrometry.

A sensitive and selective method has been developed for the determination of mevalonic acid (MVA), a cholesterol biosynthetic precursor, in dog plasma using solid-phase extraction in combination with gas chromatography/negative ion chemical ionization-mass spectrometry (GC/NICI-MS). MVA extracted from plasma with a phenylboronic acid-bonded phase cartridge was converted to its pentafluorobenzyl (PFB) ester-cyclic boronate derivative to produce a carboxyltate anion [M-PFB]- in the NlCl mode. PFB ester boronate derivatives of MVA and its internal standard, d3-mevalonolactone, were monitored in the selected ion mode at m/z 213 and 216, respectively. The precision and accuracy of within-run and between-run assays were within 8%. This method was used to follow the diurnal variation of MVA levels in plasma of fasted and fed dogs. The diurnal variations of plasma MVA levels observed between the two groups were similar to those reported previously for human and rat plasma.

Animals↗
PubMed1997

Growth hormone-releasing hormone (GRH)-producing pancreatic tumor with no evidence of multiple endocrine neoplasia type 1.

The characteristic features of a 48-year-old male presenting with isolated acromegaly caused by a GRH-producing pancreatic endocrine tumor bearing no relation to MEN1 was reported. The clinical features, laboratory findings, and sellar enlargement were improved after removal of the pancreatic tumor. The resected pancreatic tumor showed positive GRH immunoreactivity and contained abundant GRH mRNA. This tumor is extremely rare and to date only 10 cases have been reported. In the management of acromegaly, the measurement of GRH is recommended and the search for an ectopic source will prevent unnecessary and potentially ineffective pituitary surgery.

Acromegaly↗
PubMed1997

Human jaw-tongue reflex as revealed by intraoral surface recording.

The purpose of this study was to examine if there is a human jaw-tongue reflex. This study was carried out in seven healthy adult males and recorded the genioglossus muscle activity during various functions by using a miniature intraoral surface electrode, which is comparable with intramuscular fine-wire electrodes, but without pain or disturbance of the tongue movement. The ipsilateral masseteric and digastric muscle activities were simultaneously recorded with the surface electrodes. Tonic genioglossus muscle activity was recorded during clenching. A passive jaw opening elicited the stretch reflex in the masseteric muscle and increased genioglossus muscle activity. Electrical stimulation of the lower lip inhibited the tonic activity in the masseteric and genioglossus muscles during both clenching and tongue protrusion. Moreover, the latency of the inhibition in the genioglossus muscle activity was shorter during clenching than during tongue protrusion. Based on these findings, the authors conclude that the human jaw-tongue reflex exists and that the jaw-closing muscle is involved in evoking the reflex.

Adult↗
PubMed1997

Generation and characterization of rat monoclonal antibodies against human serum amyloid A.

Monoclonal antibodies against human serum amyloid A (SAA) were generated in rat (which seems not to have mature SAA proteins) by immunizing intact human SAA. Thirteen clones selected by initial screening were analysed based on reactivity with synthetic peptides of SAA and with carboxyl-terminal truncated recombinant SAA. Antibodies were divided into four types, i.e. those recognizing the area around residue 18, 30, 90, and 100, respectively, of SAA. The antibody to the carboxyl terminus (around residue 100) of SAA, when subjected to immunohistochemistry for amyloid deposits in specimens from patients with reactive amyloidosis, always yielded negative reactivity, supporting the general concept that the carboxyl terminus of SAA is absent from human AA deposits.

Amino Acid Sequence↗
PubMed1997

Formation of multimers of cucumber mosaic virus satellite RNA.

Double-stranded RNA multimers of cucumber mosaic virus (CMV) satellite RNA were detected in CMV-infected plants. RT-PCR showed that plus-sense and minus-sense monomers and plus-sense multimers of satellite RNA were present. Multimeric minus-sense RNA was not present except in the form of multimeric dsRNA. Sequence analysis of 52 cloned junction regions in head-to-tail repeats of unit-length satellite RNA indicated that about 35% of the junction sequences were precise fusions of monomer units, 56% lacked sequence of the 5' component, and 10% lacked sequence of both 3' and 5' components. No junction contained additional nucleotides. Deletions at the junction regions may have accumulated during CMV multiplication in inoculated plants. These data suggest that replicase is not released from the template during synthesis of multimeric molecules of satellite RNA.

Base Sequence↗