Search PubMed⌕ Search

Biomedical subjects

M Suzuki

Publications and source records attributed to M Suzuki.

At least 73 records · Page 4Linked to original sources
PubMed2005

The usefulness of continuous administration of hypoxic cytotoxin combined with mild temperature hyperthermia, with reference to effects on quiescent tumour cell populations.

To evaluate the usefulness of continuous administration of hypoxic cytotoxins in terms of targeting acute hypoxia in solid tumours and the significance of combination with mild temperature hyperthermia (MTH) (40 degrees C, 60 min), the cytotoxic effects of singly or continuously administered tirapazamine (TPZ) and TX-402 were examined in combination with or without MTH in vivo. Further, the effects were also analysed on total (=proliferating (P)+quiescent (Q)) and Q cell populations in solid tumours with the method for selectively detecting the Q cell response. C3H/He mice bearing SCC VII tumours received a continuous administration of 5-bromo-2'-deoxyuridine (BrdU) for 5 days to label all P cells. The tumour-bearing mice then received a single intra-peritoneal injection or 24 h continuous subcutaneous infusion of hypoxic cytotoxin, TPZ or TX-402, with or without MTH. On the other hand, to detect the changes in the hypoxic fraction (HF) in the tumours by MTH, another group of mice with or without MTH received a series of test doses of gamma-rays while alive or after tumour clamping. After each treatment, the tumour cells were isolated and incubated with a cytokinesis blocker (=cytochalasin-B) and the micronucleus (MN) frequency in cells without BrdU labelling (=Q cells) was determined using immunofluorescence staining for BrdU. The MN frequency in total tumour cells was determined from the tumours that were not pre-treated with BrdU. The sensitivity to TX-402 was slightly higher than that to TPZ in both total and Q tumour cells. Continuous administration elevated the sensitivity of both total and Q cells, especially total cells. MTH raised the sensitivity of Q cells more remarkably than that of total cells in both single and continuous administrations. It was thought to be probably because of the higher dose distribution of hypoxic cytotoxin in intermediately hypoxic areas derived mainly from chronic hypoxia through MTH. From the viewpoint of tumour control as a whole including both total and Q tumour cells, the continuous administration of hypoxic cytotoxin combined with MTH may be useful for sensitizing tumour cells in vivo.

Animals↗
PubMed2005

Use of real-time magnetic resonance image guidance in endoscopic sinus surgery.

We evaluated the effectiveness of magnetic resonance image (MRI) guidance using an optical tracking system (MRI-guided therapy: MRT) in performing endoscopic sinus surgery (ESS). The profiles of the fourteen patients in the present study were as follows: eleven with mucocele in the paranasal sinus, one with recurrent chronic sinusitis, one with maxillary cancer, and one with Graves' ophthalmopathy. Preparation of the MRT system required an additional 54 min in cases involving general anesthesia, and an additional 17 min in cases involving local anesthesia, in comparison with corresponding control groups undergoing ESS in a traditional operating room. We developed nonmetal probes that were visualized in a real-time mode and assistive devices for the optical tracking system that were equipped to avoid obstruction caused by surgical instruments as well as by the hands of surgeons. Using these unique devices, anatomic landmarks were visualized using the present MRT system. The prognosis of patients was favorable, and in particular, no patients with sinus mucocele showed a recurrence of their lesions. We concluded that the MRT system used here for performing ESS was beneficial, especially in terms of the intranasal marsupialization of sinus mucoceles and for the verification of orbital contents.

Journal Article↗
PubMed2005

Mode of action of piscicocin CS526 produced by Carnobacterium piscicola CS526.

AIMS: Piscicocin CS526 is a unique class IIa bacteriocin produced by Carnobacterium piscicola CS526. The mode of action against the sensitive strain Listeria monocytogenes IID581 was evaluated. METHODS AND RESULTS: Piscicocin CS526 was adsorbed on both sensitive and insensitive gram-positive and gram-negative bacterial cells. Treatment of L. monocytogenes cells with trypsin, lipase and Triton X-100 did not reduce subsequent adsorption of piscicocin CS526. The activity of piscicocin CS526 against L. monocytogenes cells was bactericidal rather than bacteriostatic, but did not cause bacteriolysis. Piscicocin CS526 induced the efflux of K+ ions from the target cells which cause dissipation of the transmembrane potential (DeltaPsi) of the cell membrane. Moreover, after exposure to piscicocin CS526, intracellular adenosine 5'-triphosphate (ATP) level of the target cells rapidly reduced without leakage of ATP from the cells, indicating that ATP depletion occurred in the cells. CONCLUSIONS: Pore formation by piscicocin CS526 caused a rapid efflux of small molecules such as K+ from the indicator cells and dissipation of proton motive force (PMF), which lead to the cell death. SIGNIFICANCE AND IMPACT OF THE STUDY: Molecular mechanism of action of piscicocin CS526 is very similar to that of other pediocin-like bacteriocins, although piscicocin CS526 possesses a unique N-terminal sequence in which Val is substituted for by Leu in the amino acid at position 7.

Adenosine Triphosphate↗
PubMed2005

Carcinosarcoma of the parotid gland: an unusual case with large-cell neuroendocrine carcinoma and rhabdomyosarcoma.

We report a case of carcinosarcoma of the parotid gland in a 72-year-old Japanese man. The patient noticed a rapidly enlarging hard mass in the right parotid gland. He underwent radical parotidectomy with cervical lymph node dissection. The resected tumor measured 3.5 x 4.5 cm and histopathologically showed carcinomatous and sarcomatous components. The carcinomatous component consisted of large-cell neuroendocrine carcinoma (LCNEC), squamous cell carcinoma and adenocarcinoma not otherwise specified, while the sarcomatous component included spindle cell sarcoma not otherwise specified, so-called myxosarcoma and rhabdomyosarcoma. The LCNEC component was predominant within the whole tumor. The diagnoses of LCNEC and rhabdomyosarcoma were also confirmed immunohistochemically. With regard to histopathogenesis, based on the lack of histopathological evidence and antecedent history of pleomorphic adenoma, we considered the present case to be de novo, not expleomorphic adenoma.

Aged↗
PubMed2005

Preliminary results of moisture checker for Mucus in diagnosing dry mouth.

OBJECTIVE: To evaluate the ability of Moisture Checker for Mucus (MCM), a device which measures the weight percent of water content in the oral mucosal epithelium, for the diagnosis of dry mouth. METHOD: Forty-three consecutive patients seen at the Dry Mouth Clinic of Tsurumi University were divided into two groups by the diagnostic criteria of hyposalivation defined by the stimulated salivary flow rate < or =10 ml per 10 min. The MCM values in the buccal, tongue and labial mucosa in each group were compared. RESULTS: The value of the normal salivation group was significantly higher when compared with that of the hyposalivation group both in the buccal and tongue mucosa, P = 0.01 and P = 0.046, respectively. CONCLUSION: Moisture Checker for Mucus has the potential to be a useful device in the screening of hyposalivation.

Adult↗
PubMed2005

Polymorphism of the 5' flanking region of the IL-12 receptor beta2 gene partially determines the clinical types of leprosy through impaired transcriptional activity.

BACKGROUND: Individual differences in T cell responsiveness to interleukin 12 (IL-12), resulting from inherited factors, may be responsible for differences in the intensity of cell mediated immune (CMI) responses in patients with leprosy, a disease with a wide clinical spectrum. AIM: Polymorphisms in the 5' flanking region of the IL12RB2 gene were analysed to determine potential immunogenetic factors affecting CMI responses, using leprosy as a model. METHODS: Polymorphisms in the 5' flanking region of IL12RB2 were examined using direct sequencing techniques, and allele frequencies between patients with lepromatous leprosy and patients with tuberculoid leprosy were compared. The effect of these single nucleotide polymorphisms (SNPs) on IL12RB2 expression was estimated using the dual luciferase reporter gene assay in Jurkat T cells. RESULTS: Several SNPs, including -1035A>G, -1023A>G, -650delG, and -465A>G, were detected within the 5' flanking region of IL12RB2. The frequency of haplotype 1 (-1035A, -1023A, -650G, -464A) was high in the general Japanese population, but was significantly lower in lepromatous patients compared with tuberculoid patients and healthy controls. Reporter gene assays using Jurkat T cells revealed that all haplotypes carrying one or more SNP exhibited a lower transcriptional activity compared with haplotype 1. CONCLUSION: SNPs within the 5' flanking region of IL12RB2 affect the degree of expression of this gene and may be implicated in individual differences in CMI responsiveness to mycobacterial antigens, leading to lepromatous or tuberculoid leprosy.

5' Flanking Region↗
PubMed2005

Immunocytochemical and phylogenetic distribution of aquaporins in the frog ventral skin and urinary bladder.

We recently cloned three cDNAs encoding frog aquaporin (AQP-h1, BAC07470; AQP-h2, BAC82379; and AQP-h3, BAC07471) from the ventral pelvic skin of the tree frog, Hyla japonica. The present study demonstrated that Hyla AQP-h2 was translocated from cytoplasmic pools to the apical plasma membranes of the granular cells in the bladder after antidiuretic hormone stimulation and that Hyla AQP-h2 and AQP-h3 behaved similarly in the ventral pelvic skin. Further, we found that terrestrial and tree frogs, but not aquatic and semiterrestrial-adapted frogs, absorbed water from their ventral pelvic skin by AQP-h3-like protein in concert with AQP-h2-like protein.

Animals↗
PubMed2005

Collagenofibrotic glomerulonephropathy in a cynomolgus macaque (Macaca fascicularis).

Collagenofibrotic glomerulonephropathy (CFGN) is characterized by the deposition of type III collagen within the mesangial matrix and the absence of mesangial cell proliferation. A case of CFGN in a 2.7-year-old female cynomolgus macaque was investigated in the present study. Clinically, the animal was shown to have severe systemic edema along with hypoproteinemia. At necropsy, the kidneys were swollen and pale. The glomerular lesions were characterized by massive diffuse and global accumulation of fibrous materials in the mesangial areas. Neither mesangial cell proliferation nor changes in other organs were found. The fibrous materials were confirmed by the results of immunohistochemical and electron microscopic findings to consist mainly of randomly arranged, curve-shaped, twisted, and entwined type III collagen. This is the first case report of CFGN in nonhuman primates to date.

Animals↗
PubMed2005

Reduction in life span of normal human fibroblasts exposed to very low-dose-rate charged particles.

We studied the effect of chronic low-dose irradiation with heavy ions on the life span of normal human fibroblasts in vitro. Cells were cultured in a CO2 incubator that was placed in the irradiation room for biological studies of heavy ions in the Heavy Ion Medical Accelerator in Chiba (HIMAC) at National Institute of Radiological Sciences (NIRS) and were exposed to scattered radiations produced by heavy-ion beams for the life span of the cell population. The absorbed dose, which was measured using a thermoluminescence dosimeter (TLD) and a silicon semiconductor detector, was 1.4 mGy per day when the HIMAC was operated for biological experiments. The total number of population doublings of the exposed cells as reduced to 79-93% of that of nonexposed control cells. However, the life span of cells exposed to low-dose 137Cs gamma rays (approximately 1 mGy/day) in the CO2 incubator in the gamma-irradiation room in NIRS was prolonged to 104-106% of that of nonexposed control cells. Thus there is evidence that exposure to chronic low-dose heavy-ion radiation reduces the life span of cells.

Cell Count↗
PubMed2005

Differential effects of sex steroid hormones on the expression of multiple first exons including a novel first exon of prolactin receptor gene in the rat liver.

In addition to the known four alternative first exons E1(1), E1(2), E1(3) and E1(4) of the rat prolactin receptor (PRL-R) gene, a novel first exon, E1(5), was identified by cDNA cloning of the 5'-end region of PRL-R mRNA in the rat liver. Genomic fragments containing E1(5) and its 5'- or 3'-flanking regions were also cloned from rat kidney genomic DNA. A sequence search for E1(5) revealed that E1(5) is located 49 kb upstream of exon 2 of the PRL-R gene in rat chromosome 2q16. RT-PCR analysis revealed that E1(5) was preferentially expressed in the liver, brain and kidney. Expression profiles of E1(2)-, E1(3)- and E1(5)-PRL-R mRNAs in the liver of male and female rats at 5 days of age and those at 8 weeks of age were examined by RT-PCR. The levels of E1(2)-PRL-R mRNA in the female rat increased remarkably in rats at 8 weeks of age compared with those at 5 days of age, and the levels of E1(5)-PRL-R mRNA in the male rat decreased markedly at 8 weeks of age compared with those at 5 days of age. In the female rat, the levels of E1(2)-PRL-R mRNA at 8 weeks of age decreased with ovariectomy performed at 4 weeks of age and recovered with the administration of beta-oestradiol. On the contrary, the levels of E1(5)-PRL-R mRNA increased with ovariectomy and decreased with the oestrogen treatment. In the male rat liver, the levels of E1(2)-PRL-R mRNA at 8 weeks of age increased strikingly with castration performed at 4 weeks of age and became undetectable with the administration of testosterone. The levels of E1(5)-PRL-R mRNA increased slightly with castration and were restored by testosterone treatment. Removal of gonadal tissues and sex steroid hormone treatment had no effect on the expression levels of E1(3)-PRL-R mRNA in both female and male rat livers. These results indicated that the expression of the PRL-R gene in the liver is regulated by the differential effects of sex steroid hormones on the transcription of the multiple first exons including the novel one.

Animals↗
PubMed2005

A case of gain-of-function mutation in calcium-sensing receptor: supplemental hydration is required for renal protection.

AIMS: The calcium-sensing receptor (CaSR) regulates the extracellular calcium level, mainly by controlling parathyroid hormon secretion and renal calcium reabsorption. In gain-of-function CaSR mutations, the genetic abnormalities increase CaSR activity leading to the development of such clinical manifestations as hypercalciuric hypocalcemia and hypoparathyroidism. We report a Japanese case of CaSR gain-of-function mutation and represent a therapeutic intervention based on the functional characteristics of CaSR in renal tubule. METHODS AND RESULTS (CASE): DNA sequence analysis revealed a heterozygous G to T mutation identified in a 12-year-old Japanese girl presenting with sporadic onset of hypercalciuric hypocalcemia and hypoparathyroidism. The mutation is located in the N-terminal extracellular domain of the CaSR gene, one of the most important parts for the three-dimensional construction of the receptor, resulting in the substitution of phenylalanine for cysteine at amino acid 131 (C131F) in exon 3. Based on the diagnosis of the gain-of-function mutation in the CaSR, oral hydrochlorothiazide administration and supplemental hydration were started in addition to calcium supplementation. The combination therapy of thiazide and supplemental hydration markedly reduced both renal calcium excretion and urinary calcium concentration from 0.4-0.7 to less than 0.1 mg/mg (urinary calcium/creatinine ratio) and from 10-15 to 3-5 mg/dl (urinary calcium concentration), respectively. This therapy stopped the progression of renal calcification during the follow-up period. CONCLUSION: Supplemental hydration should be considered essential for the following reasons: (1) calcium supplementation activates the CaSR in the kidney and suppresses renal urinary concentrating ability, (2) the thiazide has a diuretic effect, (3) as calcium supplementation increases renal calcium excretion, the supplemental hydration decreases urinary calcium concentration by increasing urinary volume, thereby diminishing the risk of intratubular crystallization of calcium ion.

Administration, Oral↗
PubMed2005

[The use of fibrous wound dressing sheets made of carboxymethylcellulose natrium in the postoperative management of tracheostomy].

Postoperative management of tracheostomy is very important to reduce several complications such as abnormal granulation and subcutaneous abscess. One of the causes is the use of gauzes and a disinfectant because they induce the secondary wound injury and prevention of wound healing. We used a fibrous wound dressing, carboxymethylcellulose natrium sheet (Aquacel) on the postoperative management of tracheostomy for 5 patients. The sheets were very useful to absorb exudates including blood and to make suitable moist and clean surroundings in all patients.

Aged↗
PubMed2004

Clinically mild encephalitis/encephalopathy with a reversible splenial lesion.

OBJECTIVE: To clarify whether patients with clinical diagnoses of encephalitis/encephalopathy with a reversible lesion in the splenium of the corpus callosum (SCC) share common clinical features. METHODS: Possible encephalitis/encephalopathy patients with a reversible isolated SCC lesion on MRI were collected retrospectively. Their clinical, laboratory, and radiologic data were reviewed. RESULTS: Fifteen encephalitis/encephalopathy patients with a reversible isolated SCC lesion were identified among 22 patients referred for this study. All 15 patients had relatively mild clinical courses. Twelve of the 15 patients had disorders of consciousness. Eight patients had seizures, and three of them received antiepileptic drugs. All 15 patients clinically recovered completely within 1 month (8 patients within a week) after the onset of neurologic symptoms. The SCC lesion was ovoid in six patients; it extended irregularly from the center to the lateral portion of SCC in the other eight patients. Homogeneously reduced diffusion was seen in all seven patients who underwent diffusion-weighted imaging. There was no enhancement in the five patients so examined. The SCC lesion had completely disappeared in all patients at follow-up MRI exams between 3 days and 2 months after the initial MRI (within 1 week in eight patients). CONCLUSION: The clinical features among the affected patients were nearly identical, consisting of relatively mild CNS manifestations and complete recovery within 1 month.

Adolescent↗
PubMed2004

Serine-arginine-rich nuclear protein Luc7l regulates myogenesis in mice.

Using a gene trap technique, we identified a murine homologue of the yeast LUC7-like gene (Luc7l), which is a serine-arginine-rich protein (SR protein) that localizes in the nucleus through its arginine-serine-rich domain (RS domain) at the C-terminus and shows a speckled distribution pattern. Although its transcripts are widely expressed in embryos and adults, they are rarely detected in adult skeletal muscle, and Luc7l expression was found to be negatively regulated during the course of development of limb skeletal muscle, as well as during in vitro differentiation of the myoblast cell lines Sol8 and C2C12. We also demonstrated that forced expression of Luc7l protein inhibited myogenesis in vitro. Based on our results, Luc7l is thought to play an important role in the regulation of muscle differentiation.

Animals↗
PubMed2004

Direct observation of ferromagnetic spin polarization in gold nanoparticles.

We report the first direct observation of ferromagnetic spin polarization of Au nanoparticles with a mean diameter of 1.9 nm using x-ray magnetic circular dichroism (XMCD). Owing to the element selectivity of XMCD, only the gold magnetization is explored. Magnetization of gold atoms as estimated by XMCD shows a good agreement with results obtained by conventional magnetometry. This evidences intrinsic spin polarization in nanosized gold.

Journal Article↗