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Biomedical subjects

I Suzuki

Publications and source records attributed to I Suzuki.

At least 55 records · Page 3Linked to original sources
PubMed2000

Association between a C+33T polymorphism in the IL-4 promoter region and total serum IgE levels.

Susceptibility to asthma and other atopic diseases is known to be associated with elevated total IgE levels. Several investigators have linked the interleukin-4 (IL-4) gene and nearby markers located on chromosome 5q to elevated total IgE levels. A single nucleotide polymorphism in the IL-4 gene promoter region (C+33T) has recently been identified. As part of an effort to identify genetic variants contributing to the susceptibility to elevated total serum IgE levels, an association analysis of a newly identified promoter polymorphism (C+33T) with total serum IgE levels was conducted. The study was conducted using 240 Japanese subjects (120 asthmatics and 120 healthy controls). The IL-4 C+33T polymorphism was genotyped by PCR-restriction fragment length polymorphism analysis. The frequency of the T allele was 0.675 in asthmatic subjects and 0.671 in healthy controls. An ANOVA model adjusted for age, sex and disease status suggested a genetic association of C+33T polymorphism with elevated total serum IgE levels (P < 0.05). The data suggest that IL-4 promoter C+33T polymorphism may be one of the genetic polymorphisms that explain genetic linkage or association between elevated total serum IgE levels and markers on chromosome 5q.

Aged↗
PubMed2000

Prognostic value of vascular endothelial growth factor (VEGF) in head and neck squamous cell carcinomas.

Vascular endothelial growth factor (VEGF) has been identified as the substance that increases the permeability and proliferation of vascular endothelial cells. We examined the clinical significance of VEGF expression in 60 head and neck squamous cell carcinomas using the methods of Western blot, immunohistochemistry, and reverse transcriptase-polymerase chain reaction (RT-PCR), comparatively, and analysed the relationship between VEGF status in Western blot and tumour size, lymph-node status, histologic grade and disease-free survival (DFS) rate. Western blot analysis revealed high VEGF expressors (tumour/normal tissue density >/= 3-fold) in 26 patients (43%) and low VEGF expressors (< 3-fold) in 34 patients (57%). The results of the Western blot analysis correlated significantly with those of the RT-PCR (P = 0.00007) or immunohistochemistry (P = 0. 00006). High VEGF expressors are associated with the progression of lymph-node spread (P = 0.0009), which are correlated with poor DFS. The 2-year DFS rate of high VEGF expressors (30%) was significantly lower than that of low VEGF expressors (78%) (P = 0.0008). Multivariate analysis showed VEGF expression and stage were independent predictors for the DFS (P = 0.045 and 0.041, respectively). VEGF expression may play an important role in progression of HNSCC.

Adult↗
PubMed2000

Melanotic neuroectodermal tumor of infancy in the mandible: report of a case.

A case of melanotic neuroectodermal tumor of infancy occurring in the mandible is described. The patient was a 1-month-old boy with a rapidly growing tumor of the mandible. Computed tomography showed 2 well-defined osteolytic lesions in the right mandible. Histopathologic diagnosis of a biopsy specimen was melanotic neuroectodermal tumor of infancy. The tumor was excised with removal of the surrounding bone, but 1(1/2) months later it recurred, and segmental mandibulectomy and reconstruction of the defect with a titanium miniplate was performed. Retrospectively, evidence of recurrence was noted on computed tomography taken on the tenth postoperative day. The recurrence was caused by incomplete removal of the tumor. Histopathologically, the tumor cells of the recurrent lesion were dispersed extensively in the bone marrow, and bone remodeling was active. The surgical procedure may have stimulated tumor cell proliferation and reactive bone formation. The patient was followed for 2 years with no evidence of recurrence or metastasis.

Humans↗
PubMed2000

Levels of beta-human chorionic gonadotropin in cerebrospinal fluid of patients with malignant germ cell tumor can be used to detect early recurrence and monitor the response to treatment.

BACKGROUND: Tumor marker-producing germ cell tumors of the central nervous system are malignant and require radiation and/or chemotherapy. Although serum beta-human chorionic gonadotropin (hCG) has been used to monitor the course of treatment, the levels of beta-hCG in the cerebrospinal fluid (CSF) have not been measured routinely in the clinic. To determine whether they can be used to evaluate parameters of tumor status, such as progression or response to therapy, levels of beta-hCG in the serum and CSF of patients with germ cell tumors were studied. METHODS: Fifty-four paired samples of CSF and serum were taken from seven patients with germ cell tumor and their beta-hCG levels were measured. Beta-hCG was negative in both serum and CSF in 11 instances and the levels in the other 43 paired samples were analyzed for any correlation or relationship to therapy. They were also compared with the clinical courses. RESULTS: The mean CSF beta-hCG level was 11.5 mIU/ml, which was significantly higher than the level in serum (3.5, p = 0.002). In all the paired samples except for one time point, the level in CSF was higher than that in serum. Out of 43 instances where the beta-hCG level in CSF was elevated, the level in serum was elevated in only 16 (37.2%). Among cases of recurrent malignant germ cell tumor, there were nine instances of recurrence or progression despite therapy. In all five instances where beta-hCG CSF levels were measured, the levels were elevated prior to any increase or detectability of the serum values. CONCLUSION: It seems likely that the level of beta-hCG in CSF is a good marker for monitoring tumor recurrence or evaluation of treatment results.

Adolescent↗
PubMed2000

Surgical indication for refractory childhood epilepsy.

Recent progress in surgical intervention for medically refractory epilepsy has helped to shed light on more complex epileptogenic problems in children and infants. Surgical treatment increasingly is being used in pediatric patients, but the indications for surgery in this age group have not been well defined. The developing child with a seizure disorder has several problems that are different from adults, such as neural plasticity, deleterious effects of seizures on developmental status, and spontaneous resolution of epilepsy. The critical age for irreversible brain dysfunction and the timing of surgery are the main issues for the treatment of children. Thus, earlier surgical intervention is generally recommended to prevent further detrimental seizure effects, but we still do not know the optimal age. Until the establishment of guidelines for pediatric epilepsy surgery, surgical indications should be determined by the prognosis and the presence of a resectable epileptogenic focus, which in turn are based on the localization of the epileptic focus, seizure frequency, severity, and cognitive function of each case, rather than just the patient's age.

Age Factors↗
PubMed2000

Purification and properties of an enzyme capable of degrading the sheath of Sphaerotilus natans.

Microorganisms which can degrade and grow on the purified sheath of a sheathed bacterium Sphaerotilus natans were collected from soil and river water. Two bacterial strains were isolated from the soil and designated strains TB and TK. Both strains are rod shaped, negatively stained by gram staining, facultatively anaerobic, and formed ellipsoidal endospores. These characteristics suggested that the isolates belong to the genus Paenibacillus, according to Ash et al. (C. Ash, F. G. Priest, and M. D. Collins, Antonie Leeuwenhoek 64:253-260, 1993). Phylogenetic analysis based on the 16S rDNA supported this possibility. Purification of the sheath-degrading enzyme was carried out from the culture broth of strain TB. The molecular weight of the enzyme was calculated to be 78,000 and 50, 000 by sodium dodecyl sulfate-polyacrylamide electrophoresis and gel filtration chromatography, respectively. Enzyme activity was optimized at pH 6.5 to 7.0 and 30 to 40 degrees C. The reaction was accelerated by the addition of Mg(2+), Ca(2+), Fe(3+), and iodoacetamide, whereas it was inhibited by the addition of Cu(2+), Mn(2+), and dithiothreitol. The enzyme acted on the polysaccharide moiety of the sheath, producing an oligosaccharide the size of which was between the sizes of maltopentaose and maltohexaose. As the reaction proceeded, the absorbance at 235 nm of the reaction mixture increased, suggesting the generation of unsaturated sugars. Incorporation of unsaturated sugars was also suggested by the thiobarbituric acid reaction. It is possible that the enzyme is not a hydrolytic enzyme but a kind of polysaccharide eliminase which acts on the basic polysaccharide.

Amino Acid Sequence↗
PubMed2000

Selective inhibition of the oxidation of ferrous iron or sulfur in Thiobacillus ferrooxidans.

The oxidation of either ferrous iron or sulfur by Thiobacillus ferrooxidans was selectively inhibited or controlled by various anions, inhibitors, and osmotic pressure. Iron oxidation was more sensitive than sulfur oxidation to inhibition by chloride, phosphate, and nitrate at low concentrations (below 0.1 M) and also to inhibition by azide and cyanide. Sulfur oxidation was more sensitive than iron oxidation to the inhibitory effect of high osmotic pressure. These differences were evident not only between iron oxidation by iron-grown cells and sulfur oxidation by sulfur-grown cells but also between the iron and sulfur oxidation activities of the same iron-grown cells. Growth experiments with ferrous iron or sulfur as an oxidizable substrate confirmed the higher sensitivity of iron oxidation to inhibition by phosphate, chloride, azide, and cyanide. Sulfur oxidation was actually stimulated by 50 mM phosphate or chloride. Leaching of Fe and Zn from pyrite (FeS(2)) and sphalerite (ZnS) by T. ferrooxidans was differentially affected by phosphate and chloride, which inhibited the solubilization of Fe without significantly affecting the solubilization of Zn.

Anions↗
PubMed2000

Langerhans cell histiocytosis limited to the pituitary-hypothalamic axis--two case reports.

Langerhans cell histiocytosis rarely presents as a solitary lesion in the pituitary-hypothalamic region, and is indistinguishable from germinoma, which occurs much more frequently, especially in Japanese. A 14-year-old girl and a 9-year-old girl presented with polydipsia and polyuria as the initial symptoms. Magnetic resonance (MR) imaging demonstrated a round mass at the pituitary stalk appearing as isointense on T1-weighted imaging and hyperintense on T2-weighted imaging. Endocrinological examination revealed mild hypopituitarism with central diabetes insipidus. Both patients underwent open craniotomy. Histological examination revealed granulomatous tissue with eosinophil infiltration and frequent Langerhans histiocyte clustering, compatible with the diagnosis of Langerhans cell histiocytosis. Low-dose local irradiation of 20 Gy was administered. First patient was followed up for 8 years, and her hypopituitarism gradually improved to a minimal level with only amenorrhea as the residual symptom. Recent MR imaging showed no residual mass at the region. Second patient was followed up for 15 months, and her diabetes insipidus is stable. MR imaging performed 5 months after the treatment showed marked reduction of the mass. These cases reemphasize the importance of histological diagnosis for lesions with similar neuroimaging appearances. Biopsy and low-dose irradiation are an effective treatment for this rare and essentially benign lesion, as opposed to attempting total removal of the mass.

Adolescent↗
PubMed2000

[Autopsied case of an extracranial internal carotid artery dissecting aneurysm].

An autopsy case of extracranial internal carotid artery (ICA) dissecting aneurysm due to atherosclerosis was reported. A 74-year-old man was admitted to our hospital with the chief complaints of hoarseness and a pulsatile mass below the left mandibular angle. Neurological examination showed no obvious deficits except left recurrent laryngeal nerve palsy. Angiography revealed narrowing of the original segment of left ICA with dissection and aneurysmal dilation at the level of C3 vertebra. Seven days after admission, the patient had a sudden onset of consciousness disturbance. The second angiography showed no obvious changes compared with the first findings except slight narrowing in the distal portion above the aneurysmal dilation. The possible mechanism was thought to be recanalization following transient occlusion of the left ICA caused by extension of dissection or intracranial embolism due to a thrombus within the aneurysm. He was managed conservatively, but unfortunately he died of pneumonia. Macroscopic autopsy showed that the aneurysm was fusiform. Histologically, it demonstrated dissection of the hematoma between the media and adventitia layer. Hemorrhage in the atheromatous plaque with disruption of the elastic lamina were observed along with severe degenerative changes of the intima, media and, in part, adventitia layer due to atherosclerosis. In addition, a dissecting aneurysm of the right iliac artery and severe arteriosclerosis were observed in the systemic arteries. On the basis of these findings, the dissecting aneurysm presumably developed after disruption of a weak portion of the atherosclerotic wall, where intraplaque hemorrhage occurred earlier. We suggest that atherosclerosis be regarded as one of the pathogenic factors capable of causing dissecting aneurysm of the extracranial ICA in elderly patients.

Aged↗
PubMed2000

Perception and transduction of low-temperature signals to induce desaturation of fatty acids.

When cells of the cyanobacterium Synechocystis sp. PCC 6803 are exposed to a low temperature, genes for fatty acid desaturases are expressed with resultant increases in the degree of unsaturation of fatty acids in membrane lipids. However, the sensor and transducers of low-temperature signals had not yet been identified. In order to identify these components we applied to the cyanobacterium Synechocystis sp. PCC 6803 the systematic disruption of all 43 putative genes for histidine kinases and random mutagenesis of the whole genome in conjunction with screening by the transcriptional activity of the promoter of the desB gene for the omega3 desaturase. This allowed us to identify two histidine kinases and a response regulator as components of the perception and transduction of low-temperature signals for the expression of genes for fatty acid desaturases.

Cold Temperature↗
PubMed2000

[Study of the radioprotective effects of TMG on teratogenic malformations in irradiated mice].

ICR mice fetuses in the organogenesis stage were used to clarify experimentally the mechanism of the protective effect of vitamin E derivant (TMG: 2-(alpha-D-Glucopyranosyl) methyl-2, -5, -7, -8-Teramethylchorman-6-working woman) on the effects of radiation. The authors paid careful attention to radiation, and the radioprotective effects of TMG on the induction of malformations was examined. Radiation is an important consideration because of its widespread use in the areas of medicine, nuclear energy, and industry. Malformations induced by radiation at the organogenesis stage, skeletal malformations, and the effects at the cellular level of embryos were examined in this research. Further, the mechanism of the protection effect of TMG against radiation-induced malformations was analyzed and observed experimentally. Thus, this study was done to provide fundamental data on the radioprotective agent TMG. It was clear that TMG exerted radioprotective effects against embryonic death and the rate of teratogenesis when administered before exposure. Such effects were also exerted against skeletal malformations and fetal body weight. In summary, radioprotective effects were observed at the whole-body level as well as at the cellular level.

Abnormalities, Radiation-Induced↗
PubMed2000

Cloning and expression of the gene encoding thermostable poly(3-hydroxybutyrate) depolymerase.

The gene encoding extracellular poly(3-hydroxybutyrate) depolymerase from a thermophilic poly(3-hydroxybutyrate)-degrading bacterium, strain HS, was cloned and intracellularly expressed in Escherichia coli. The gene was found to consist of 1485-bp nucleotide sequence coding for a 22-amino-acid signal peptide and a 473-amino-acid mature protein. Phylogenetic analysis and domain structure showed that the enzyme was clustered with type II PHB depolymerases. The gene was expressed in E. coli under the control of the tac promoter. A 46-kDa protein was detected in the cell extract by SDS-PAGE. The N-terminal sequence of the protein agreed with that of the original enzyme. The crude enzyme was able to degrade PHB particles at 70 degrees C.

Journal Article↗
PubMed1999

The melanocortin-1 receptor and human pigmentation.

alpha-Melanocyte stimulating hormone (alpha-MSH) is known to be the main physiologic regulator for integumental pigmentation of various vertebrate species. However, the role of alpha-MSH and related melanocortins in the regulation of human cutaneous pigmentation is only beginning to be understood. Cloning of the melanocortin-1 receptor (MC1R), and the feasibility of establishing normal human epidermal melanocyte cultures have made it possible to demonstrate direct and specific biological effects of alpha-MSH on these cells. It is now recognized that both alpha-MSH and ACTH have similar mitogenic and melanogenic effects on human epidermal melanocytes. These effects are mediated by binding of these hormones to the specific MC1R that recognizes them both with similar affinity. Human MC1R is homologous to its mouse counterpart in that its activation leads to stimulation of eumelanin synthesis. MC1R is also the binding site for agouti signaling protein (ASP), the product of the agouti locus. Human epidermal melanocytes respond to purified recombinant mouse or human ASP, with a reduction in basal tyrosinase activity, and complete abrogation of the mitogenic and melanogenic effects of alpha-MSH. These results suggest that ASP induces pheomelanin synthesis by competing with alpha-MSH for binding to the MC1R. This receptor seems to be subject to regulation by a variety of paracrine and/or autocrine factors that are synthesized in response to exposure of the skin to ultraviolet radiation (UVR). Activation of MC1R seems to be pivotal for UV-induced melanogenesis, since stimulation of the cAMP pathway plays a key role in the melanogenic response of human epidermal melanocytes. The melanogenic response to UVR might be influenced by the presence of allelic variants of the MC1R gene. Allelic variants have been identified and shown to be associated with red hair, poor tanning ability, and possibly melanoma. The possible influence of these variants on the function of the MC1R needs to be investigated, in order to understand the physiological consequence of these mutations. Also, the interaction of alpha-MSH with other factors that are known to affect pigmentation needs to be better understood in order to define the role possible of this hormone and its receptor in acquired human cutaneous hyper- or hypopigmentation.

Agouti Signaling Protein↗
PubMed1999

Postoperative residual tumor growth of meningioma can be predicted by MIB-1 immunohistochemistry.

BACKGROUND: Meningiomas are benign tumors that can be cured by surgical removal. However, tumors located deeply within or close to vital structures cannot be removed completely and require repeated surgery. This study was designed to clarify whether immunohistochemical study using MIB-1 monoclonal antibody is useful for determining the rate of regrowth for this tumor. METHODS: Tumor volume doubling time (Td) was measured by using computed tomography or magnetic resonance imaging neuroimages during 29 different follow-up periods after surgery. MIB-1 monoclonal antibody was used to stain Ki-67 proliferating cell antigen in surgical specimens, and the MIB-1 staining index (SI) was determined independently of neuroimaging analysis. These two values and other clinical parameters were analyzed statistically. RESULTS: The Td values varied from 19-6830 days (median, 350 days); the Td values were <365 days in 15 cases, 365-730 days in 8 cases, and >730 days in 6 cases. There was no significant correlation between age and Td value, but all 6 patients whose Td values were >2 years were age >50. There was a strong inverse correlation between log(Td) and MIB-1 SI (P < 0.001). In three cases, more than three surgical procedures were performed for tumor recurrence. The MIB-1 values did not increase at the time of the first recurrence but increased at later recurrences. The calculated Td values also were not shortened until the second recurrence. CONCLUSIONS: Using the MIB-1 SI makes it possible to predict the regrowth potential of a tumor after initial surgery.

Adult↗
PubMed1999

Genetic engineering of the unsaturation of fatty acids in membrane lipids alters the tolerance of Synechocystis to salt stress.

The role of unsaturated fatty acids in membrane lipids in the tolerance of the photosynthetic machinery to salt stress was studied by comparing the desA-/desD- mutant of Synechocystis sp. PCC 6803, which contained monounsaturated fatty acids, with the wild-type strain, which contained a full complement of polyunsaturated fatty acids. In darkness, the loss of oxygen-evolving photosystem II activity in the presence of 0.5 M NaCl or 0.5 M LiCl was much more rapid in desA-/desD- cells than in wild-type cells. Oxygen-evolving activity that had been lost during incubation with 0.5 M NaCl in darkness returned when cells were transferred to conditions that allowed photosynthesis or respiration. Recovery was much greater in wild-type than in desA-/desD- cells, and it was prevented by lincomycin. Thus, the unsaturation of fatty acids is important in the tolerance of the photosynthetic machinery to salt stress. It appears also that the activity and synthesis of the Na+/H+ antiporter system might be suppressed under high-salt conditions and that this effect can be reversed, in part, by the unsaturation of fatty acids in membrane lipids.

Cyanobacteria↗
PubMed1999

Low p27 expression correlates with poor prognosis for patients with oral tongue squamous cell carcinoma.

BACKGROUND: p27, a cyclin-dependent kinase inhibitor, regulates progression from G1 to S phase. There have been a few clinical reports of low p27 expression associated with poor survival among patients with cancer; however, there have been no reports of such an association in cases of head and neck cancer. The authors investigated whether p27 expression in patients with oral tongue squamous cell carcinoma was associated with their prognosis. METHODS: Ninety-four patients with oral tongue squamous cell carcinoma were analyzed. The authors performed p27 immunohistochemistry on all patients and Western blot analysis on 19 available patients. Cox proportional hazards regression analysis that included gender, history of smoking and alcohol usage, presence of multiple primary cancers, stage, histologic grade, and p27 status was used to identify the multivariate predictive value of prognostic factors. RESULTS: Twenty-six patients had high p27 expression (> or =50% tumor cell nuclei positive), and 68 patients had low p27 expression (<50%) by immunohistochemistry. In those with low p27 expression, N(+) and advanced T (T3 or T4) were significantly higher than in those with high p27 expression (P = 0.02 and 0.04). The 5-year survival rate in the low p27 group was 44%, whereas that in the high p27 group was 68%, indicating a significant difference (P = 0.04). p27 expression was inferred from Western blot analysis, and an arbitrary quantity (<1, 1-5, or > or =5) from the ratio of tumor to normal tissue density was used to characterize, resulting in 8 (42%), 3 (16%), and 8 (42%) patients in the low (<1-fold), intermediate (1-5-fold), and high (> or =5-fold) groups, respectively. Results of immunohistochemical analysis for p27 were significantly correlated with those of Western blot analysis (P = 0.02). Multivariate analysis revealed that low intensity of p27 expression and advanced stage (Stage III or IV) were predictors of reduced survival (P = 0.02 and 0.001). CONCLUSIONS: Low p27 expression was associated with increasing lymph node metastasis and stage of tumor and resulted in a poor prognosis for patients with oral tongue squamous cell carcinoma. p27 is apparently a significant predictor of survival.

Actins↗
PubMed1999

Spontaneous regression of a residual pineal tumor after resection of a cerebellar vermian germinoma.

A case of multiple intracranial germ cell tumor in which a pineal tumor regressed spontaneously after resection of the cerebellar mass is reported. Immunohistochemical staining of the cerebellar mass showed that most of the infiltrating lymphocytes were positive for CD3 and CD8. The anti-Ki-67 monoclonal antibody MIB-1 staining of the resected tumor revealed a high MIB-1 positivity ratio (36.1%) among the large tumor cells, and TUNEL staining demonstrated that positivity in up to 6% of the tumor cells. Possible mechanisms responsible for this spontaneous regression including immunological responses and apoptosis induced by T lymphocytes are discussed.

Adult↗