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Biomedical subjects

Yoshiaki Yamada

Publications and source records attributed to Yoshiaki Yamada.

At least 19 recordsLinked to original sources
PubMed2006

An immunohistochemical study of chromogranin A and human epidermal growth factor-2 expression using initial prostate biopsy specimens from patients with bone metastatic prostate cancer.

OBJECTIVES: To investigate, using prostate needle-biopsy specimens at diagnosis from patients with bone metastatic prostate cancer, whether the relationship between neuroendocrine (NE) cell differentiation and human epidermal growth factor-2 (HER-2) expression is a prognostic factor for outcome. PATIENTS AND METHODS: The study included 50 patients diagnosed as having bone metastatic prostate cancer between January 1998 and December 2001. We tested for NE cell differentiation by using immunohistochemical (IHC) staining for chromogranin A (CgA), and for HER-2, using a commercial test for IHC staining. RESULTS: Eleven patients (22%) were positive for CgA; there was a significant difference in the time to recurrence (P = 0.025) but no significant differences in cause-specific survival rate or survival rate after recurrence. In all, 21 patients (42%) were positive for HER-2; the cause-specific survival rate, time to recurrence and survival rate after recurrence were all significantly more favourable in the HER-2-negative group (P = 0.008, 0.049 and 0.025, respectively). In the 49 patients for whom both factors could be determined, there was no significant correlation between CgA and HER-2 positivity. CONCLUSIONS: NE cell differentiation of the primary tumour in patients with bone metastatic prostate cancer does not reflect the prognosis, whereas HER-2 overexpression is a prognostic factor for an unfavourable outcome. These results suggest that NE cell differentiation is not induced by HER-2.

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PubMed2006

Prognostic significance of immunohistochemical expression of the HER-2/neu oncoprotein in bone metastatic prostate cancer.

OBJECTIVES: To investigate the usefulness of the overexpression of the human epidermal growth factor receptor (HER-2) oncoprotein in patients with bone metastatic prostate cancer as a marker for the time to recurrence and outcome after endocrine therapy. METHODS: We studied 50 patients who had been diagnosed with bone metastatic prostate cancer. HER-2 overexpression in the prostatic tissue by biopsy was evaluated by immunohistochemistry using the Hercep test. The results were scored into four levels by two pathologists; scores greater than 1+ were considered positive. RESULTS: The HER-2 staining score was 0, 1+, 2+, 3+, and indeterminate in 28, 4, 11, 6, and 1 case, respectively. HER-2 was overexpressed (greater than 1+) in 21 patients (42%). The cause-specific survival and nonrecurrence rates were significantly lower in the HER-2-positive group than in the negative group (P = 0.0084 and P = 0.0485, respectively). Furthermore, the cause-specific survival rate after recurrence was significantly greater in the HER-2-negative group than in the positive group (P = 0.0247). CONCLUSIONS: We consider that HER-2 overexpression, as measured by immunohistochemistry, may be useful as a marker of an unfavorable prognosis by predicting the interval until relapse and outcome after endocrine therapy in patients with bone metastatic prostate cancer.

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PubMed2006

Nitric oxide modulates elicitation of reflex swallowing from the pharynx in rats.

The pharynx is very important for elicitation of reflex swallowing. The region of the pharynx is innervated by the pharyngeal branch of the glossopharyngeal nerve (GPN-ph). Nitric oxide (NO) plays an important role in various physiological functions. The purpose of this study is to investigate the contribution of NO to reflex swallowing evoked by electrical stimulation of the GPN-ph. Swallowing was evoked in urethane-anesthetized rats by application of repetitive electrical stimulation (10- to 20-microA amplitude, 10- to 20-Hz frequency, 1.0-ms duration) to the central cut end of the GPN-ph or superior laryngeal nerve. Swallowing was identified by electromyographic activity of the mylohyoid muscle. Latency to the first swallow and the interval between swallows were measured. Intravenous administration of N(G)-nitro-L-arginine (L-NNA, 0.6 mg/kg), a nonselective inhibitor of NO synthase (NOS), extremely prolonged latency to the first swallow and the interval between swallows evoked by the GPN-ph. Intraperitoneal administration of 7-nitroindazole (5.0 mg/kg), a selective inhibitor of neuronal NOS, significantly prolonged latency to the first swallow and the interval between swallows evoked by the GPN-ph. Administration of L-arginine (an NO donor, 500 mg/kg) and sodium nitroprusside (an NO releaser, 0.6 mg/kg) restored the suppression of swallowing induced by the NOS inhibitor. Superior laryngeal nerve-evoked swallowing was suppressed by administration of a higher dose of L-NNA (6.0 mg/kg). Swallowing evoked by water stimulation of the pharynx was also suppressed by L-NNA (0.6 mg/kg). These results suggest that NO plays an important role in signal processing for initiation of reflex swallowing from the pharynx.

Animals↗
PubMed2006

Cloning and characterization of vitellogenin cDNA from the common Japanese conger (Conger myriaster) and vitellogenin gene expression during ovarian development.

The major yolk protein precursor, vitellogenin (VTG) was detected in plasma from vitellogenic females and estradiol-17beta (E2)-treated immature females, but not in males and immature females by Western blotting in common Japanese conger Conger myriaster. Its molecular mass was approximately 180 kDa under denaturing and reducing conditions. The common Japanese conger VTG cDNA was cloned from the liver of vitellogenic female. It contains 5110 nucleotides including an open reading frame that encodes 1663 amino acids. The deduced amino acid sequence of the common Japanese conger VTG shares 80% identity with that of eel Anguilla japonica VTG-1, and 45-55%, 32-34% and 27-29% identity with the deduced amino acid sequences of other fish, amphibian and avian VTG with polyserine domain, respectively. In female common Japanese conger, VTG gene was highly expressed in the liver of this species similar with other oviparous vertebrates. The expression levels of VTG gene in the liver increased from the oil droplet stage to the tertiary yolk globule stage and were maintained until the migratory nucleus stage.

Amino Acid Sequence↗
PubMed2006

Influences of thermal and gustatory characteristics on sensory and motor aspects of swallowing.

Two sets of experiments were conducted to examine the effects of two sensory modalities, temperature and taste, of foods on perceptual and motor aspects of swallowing in 20 young, healthy subjects (10 subjects for each experiment). A tasteless and odorless thickening agent was the basic testing material. The first experiment compared the swallowing of foods at four temperatures ranging from 5 degrees C to 50 degrees C. Food at 50 degrees C was more acceptable for swallowing than at 5 degrees C, 20 degrees C, or 35 degrees C. The suprahyoid muscles were less active during swallowing food at 50 degrees C compared with swallowing food at the other three temperatures. The second experiment compared foods with the five basic taste qualities (sweetness, saltiness, sourness, bitterness, and umami) with a tasteless food (dissolved in distilled water) to examine the influence of gustatory sensation. The sweet and tasteless foods were somewhat more acceptable for swallowing than the sour and bitter foods. However, none of the foods differentially altered the motor parameters of swallowing. Interactive influences of temperature and gustatory sensations of foods on swallowing are discussed.

Adult↗
PubMed2006

Endoscope-assisted minilaparotomic radical retropubic prostatectomy.

OBJECTIVE: To assess the clinical efficacy of endoscope-assisted minilaparotomic radical retropubic prostatectomy (EAM-RRP) compared with conventional radical retropubic prostatectomy (cRRP). METHODS: From September 2001 to December 2003, 30 patients with localized prostate cancer were treated by EAM-RRP. The surgical manipulation was performed through the wound with thoracoscopic assistance, using standard surgical instruments. In all cases, 800 mL of blood was collected from the patient for autotransfusion. For both EAM-RRP and cRRP, the internal iliac and obturator lymph nodes were dissected before the prostate removal. Clinical indicators such as operation time, blood loss, and duration of postoperative urine incontinence were analysed in the two groups. RESULTS: The postoperative period before ambulation and the duration of postoperative urine incontinence were significantly shorter after EAM-RRP than after cRRP, while no significant difference was found in operation time, blood loss, and duration of urethral catheterization. None of the cases required allotransfusion. CONCLUSION: EAM-RRP, which had a shorter postoperative period before ambulation and continence, is considered a safe and useful technique for radical prostatectomy.

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PubMed2006

Differential profiling analysis of proteins involved in anti-proliferative effect of interferon-alpha on renal cell carcinoma cell lines by protein biochip technology.

Interferon-alpha (IFN) is widely used for the treatment of progressive renal cell carcinoma (RCC), but its effective response rate is only about 15%. New biomarkers of RCC contributing to the effective IFN treatment are needed to establish a sensitivity test for evaluating if the IFN is effective or not against RCC. All the proteins expressed in the IFN-susceptible and -resistant RCC cell lysates were analyzed by surface enhanced laser desorption ionization (SELDI) mass spectrometry using ProteinChip technology and their different protein expression were detected by the comparison of the profiles between them. We detected the following candidate markers that exhibited peak shifts: a) in the IFN-susceptible cell lines, a candidate marker with a molecular weight of 5,688 Da was detected on a hydrophobic (H4) chip: b) in the IFN-resistant cell lines, candidate markers each with a molecular weight of 8,049, 3,157, 3,993, and 8,959 Da were detected on strong anion exchange (SAX2, pH 9.0, two types) chips, H4 chip, and weak cation exchange (WCX, pH 9.0) chips, respectively. IFN treatment produced no weight increase in these four proteins, and c) candidate marker with a molecular weight of 1,623 Da that was expressed in both cell lines after the IFN treatment was detected on the H4 chip. These data suggest that the ProteinChip system is very useful in identifying proteins showing unique peaks in the RCC cell lines with different IFN susceptibility, and the comparison of these proteins measured in RCC cell lysates may help to identify the IFN sensitivity. Furthermore, the discovery of a susceptibility and or a inhibitory factor may eventually lead to the development of a novel drug targeting the respective factor for the improvement of anticancer chemotherapy.

Antineoplastic Agents↗
PubMed2006

Is neuroendocrine cell differentiation detected using chromogranin A from patients with bone metastatic prostate cancer a prognostic factor for outcome?

We evaluated the usefulness of overexpression of neuroendrocrine (NE) cell differentiation determined by immunohistochemical staining for chromogranin A (Cg A) in diagnostic needle biopsy specimens of bone metastatic prostate cancers. A total of 50 patients diagnosed as having bone metastatic prostate cancer were studied. The period of observation was between 6.9 and 79.4 months (median 48.7 months). Cg A was detected by immunostaining using the labeled streptavidin biotin method. Cg A-positivity was defined as the presence of immunostained cells in 10% or more of the tumor. All statistical analyses were carried out using the Statistical Package for Social Sciences Software, version 10.0 for Windows. Eleven patients (22%) were classified into the Cg A-positive group. There were no significant differences in clinical data between the Cg A-positive and Cg A-negative groups. The 5-year cause-specific survival rate was 34.1% for the Cg A-positive group and 55.2% for the Cg A-negative group (p=0.3763). The 3-year non-recurrence rate was 9.1% for the Cg A-positive group and 35.9% for the Cg A-negative group, and this difference was significant (p=0.0253). The 3-year cause-specific survival rates after recurrence were 38.4% and 42.3% respectively (p=0.8125). We consider that NE cell differentiation of the primary tumor in cases of bone metastatic prostate cancer is not a prognostic factor for outcome.

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PubMed2006

Thymidine phosphorylase expression as a prognostic marker for predicting recurrence in primary superficial bladder cancer.

No prognostic marker for predicting recurrence in primary superficial bladder cancer has been established. The aim of this study was to investigate the expression levels of thymidine phosphorylase (TP) by enzyme-linked immunosorbent assay (ELISA) and the immunohistological localization of TP in primary superficial bladder cancer tissue to assess its association with tumor recurrence and stage progression as well as the pathological parameters of the tumor. TP expression in cancer tissues from 77 patients was measured by sandwich-type ELISA. Clinicopathological factors and the clinical prognosis were examined in relation to the expression levels of TP. To clarify the clinicopathological implication of TP localization in primary superficial bladder cancer tissue, the immunohistochemically determined TP expression was assessed for histological grades 1-3. The TP expression in primary superficial bladder cancer significantly increased with the histological grade and stage. The TP expression in patients with a shift to invasive cancer was significantly higher than in those without invasive cancer. Patients with low TP expression had a significant longer postoperative tumor-free period than those with high TP expression (P=0.011). High TP expression was an independent prognostic factor for tumor recurrence (P=0.0441). Strong immunoreactivity for TP was observed in the cytoplasms of tumor cells and vascular endothelial cells. This study suggests that elevated TP expression may be a prognostic marker for predicting recurrence in primary superficial bladder cancer, and that high TP expression may be associated with the marked proliferation of tumor cells and increased vascular endothelial cells, showing strong immunoreactivity for TP.

Adult↗
PubMed2005

Changes in reflex responses of the genioglossus muscle during sleep in rabbits.

Changes in reflex responses in the genioglossus (GG) muscle evoked by electrical stimulation of the inferior alveolar nerve and GG muscle tone (background activity, BGA) were investigated during sleep-wakefulness stages in rabbits. The GG muscle showed two types of electromyographic activity patterns: a respiration-related phasic activity and non-respiration-related activity. GG reflex responses and BGA exhibited a stage-dependent decrease as they were constantly suppressed from quiet wakefulness to non-rapid eye movement sleep to rapid eye movement sleep (REMS). Degree of suppression of reflexes was much larger than that of BGA regardless of GG activity patterns. When amplitude of reflex responses was compared between with and without rapid eye movements during REMS, no difference between the conditions was noted. These results suggest that excitability of the GG muscle is affected by sleep stages by not only a modulation of excitability in motoneurons but also in interneurons involved in the reflex arc.

Animals↗
PubMed2005

Preparation of a novel PEG-clay hybrid as a DDS material: dispersion stability and sustained release profiles.

An advanced hybrid drug carrier has been developed using porous nanocrystals of a swelling clay mineral conjugated with a block copolymer containing poly(ethylene glycol) and polyamine segments. Synthetic hectorite (Laponite) modified with (alpha-acetal-poly(ethylene glycol)-block-[poly(2-(N,N-dimethylamino) ethyl methacrylate)] (Acetal-PEG-b-PAMA) produced a homogeneous dispersion of organic-inorganic hybrid in an aqueous solution, which showed flocculation-resistive properties with an elevated ionic strength. The zeta-potential measurement revealed that nonionic PEG brush layers are formed on the surface of the clay nanocrystals since negative charge of the clay surface was completely neutralized by the positive charge of the cationic PAMA segment and the entire surface charge is successfully shielded by the effect of nonionic PEG segment in the block copolymer. This charge neutralization is in good agreement with the dispersion stability in solutions of high ionic strength. The average particle size of the PEG-modified hybrid particle was estimated to be 120 nm by a dynamic light scattering (DLS) method. When pyrene was used as the model compound of hydrophobic drug, it was incorporated into the nanopore in the clay mineral without showing any remarkable expansion of the basal spacings. Fluorescence spectra and powder X-ray diffraction patterns demonstrated that pyrene molecules are captured in an amorphous state in the range of low pyrene content (<5%), while excimer formation was seen at the higher pyrene concentration (>5%). The PEG-clay hybrid act as a carrier for sustained release of hydrophobic substances due to the high affinity (K = 1.52 x 10(4)) between the drug and clay surface.

Algorithms↗
PubMed2005

Unilateral application of an inflammatory irritant to the rat temporomandibular joint region produces bilateral modulation of the jaw-opening reflex.

The aim of this study was to determine the effect of unilateral acute inflammation of craniofacial deep tissues on the ipsilateral and contralateral jaw-opening reflex (JOR). The effects of mustard oil (MO), injected into the temporomandibular joint region, were tested on the JOR recorded in the digastric muscle and evoked by low-intensity electrical stimulation of the ipsilateral and contralateral inferior alveolar nerve in anesthetized rats. The MO injection induced a long-lasting suppression of the amplitude of both ipsilaterally and contralaterally evoked JOR, although the latency and duration of the JOR were unaffected. The suppressive effect was more prominent for the contralaterally evoked JOR, and observed even when background activity in the digastric muscle was increased by the MO injection. The results indicate that changes in the JOR amplitude following MO injection do not simply reflect alterations in motoneuronal excitability, and suggest that inflammation of deep craniofacial tissues modulates low-threshold sensory transmission to the motoneurons.

Analysis of Variance↗
PubMed2005

Coordination of cranial motoneurons during mastication.

Mastication is the first stage of digestion and involves several motor processes such as food intake, intra-oral food transport, bolus formation and chewing in its broad sense. These complicated motor functions can be accomplished by the well-coordinated activities in various cranial motoneurons innervating the jaw, hyoid, tongue and facial muscles. The brainstem masticatory central pattern generator (CPG) plays a crucial role in generating basic activity patterns of these cranial motoneuron groups. However, descending inputs from higher brain (e.g., cerebral cortex) and mastication-generated peripheral sensory inputs also play important roles in modulating the activity pattern of each motoneuron so that the final motor outputs fit the environmental demand. In this review, we focus on the coordination of the trigeminal, facial and hypoglossal motoneurons during mastication. We first summarize findings showing the activity patterns of muscles innervated by these motoneurons during natural mastication, and then discuss the possible neural mechanisms underlying their coordinated activities during mastication.

Animals↗
PubMed2005

Modulation of jaw reflexes induced by noxious stimulation to the muscle in anesthetized rats.

Previous studies have shown that jaw reflexes and activity patterns of the jaw muscles were modulated in the presence of jaw muscle pain. However, there is no study comparing the modulatory effects on the jaw reflexes induced by noxious stimulation to the jaw muscle. To clarify this, effects of the application of mustard oil (MO), an inflammatory irritant, into the temporalis (jaw-closing) muscle on (1) jaw-opening reflex evoked by tooth pulp stimulation (TP-evoked JOR) as a nociceptive reflex, (2) jaw-opening reflex evoked by inferior alveolar nerve stimulation as a non-nociceptive reflex and (3) jaw-closing reflex evoked by trigeminal mesencephalic nucleus stimulation as a proprioceptive reflex were investigated in anesthetized rats. The MO application induced suppression of all reflexes, and the effect on the TP-evoked JOR was more prominent than on the other reflexes. To elucidate the involvement of endogenous opioid system for the suppressive effect, a systemic administration of naloxone following the MO application was conducted. The MO-induced suppressive effect on the TP-evoked JOR was reversed by the naloxone administration. The results suggest that noxious stimulation to the jaw muscle modulate jaw reflexes particularly for the nociceptive jaw-opening reflex, and the modulatory effect includes both facilitatory and inhibitory aspects. The results also suggest that pain modulatory systems such as the endogenous opioid system play a crucial role in the suppression of the nociceptive transmissions related to nociceptive reflexes, and in some pathological states, defense reflexes may not be evoked properly.

Analysis of Variance↗
PubMed2005

Genesis of the decrement of intraluminal pressure in the UES during swallowing in rabbits.

The intraluminal pressure in the upper esophageal sphincter (UES) briefly decreases during swallowing. This decrement in pressure plays an important role in smooth transport of the ingested bolus from the pharynx to the esophagus. It is known that the decrement is caused by cessation of tonic activity of the cricopharyngeus (CP) muscle and also by elevation of the larynx. On the other hand, it is suspected that the recurrent laryngeal nerve (RLN) also contributes to the decrement, since our preliminary study showed for the first time that the decrement in UES pressure was much reduced after the RLN was sectioned. In the present study, we examined the genesis of the decrement of the UES pressure in anesthetized rabbits. When swallowing was elicited by repetitive electrical stimulation of the superior laryngeal nerve, the UES pressure briefly decreased and then abruptly increased. After bilateral sectioning of the RLN, the decrement of the pressure was significantly reduced, whereas the increment was little altered. Sectioning of the pharyngeal branch of the vagus nerve (X-ph) and the RLN mostly eliminated both the decrement and increment of the pressure, and abolished tonic and burst activities of the CP muscle. Electrical stimulation of peripheral end of the RLN decreased the pressure. These results indicate that the RLN and X-ph are involved in the decrement of the UES pressure during swallowing. The RLN generates the decrement by adducting the arytenoid cartilage and closing the glottis. The X-ph contributes to the decrement both by suppressing the tonic activity of the CP muscle and by regulating the laryngeal elevation.

Animals↗
PubMed2005

Immunohistochemical study of chromogranin A in Stage D2 prostate cancer.

OBJECTIVES: To study the clinical and pathologic factors that affect the time to recurrence after hormonal therapy in patients with Stage D2 prostate cancer and to determine whether cells positive for chromogranin A (CgA) in tissue biopsied at diagnosis is a useful marker for predicting the duration to recurrence after hormonal therapy. METHODS: A total of 50 patients diagnosed with Stage D2 prostate cancer at our institution from January 1998 to December 2001 were studied. The needle prostate biopsy specimens obtained at diagnosis were stained by immunohistochemistry using the labeled streptavidin biotin method, and the results were considered positive if CgA-positive cells constituted 10% or more of the tumor area. RESULTS: No significant differences were found between patients on the basis of the time to recurrence of less than 2 years versus 2 years or more with respect to prostate-specific antigen level, patient age, Gleason score, or extent-of-disease grade. Of the 50 patients, 11 (22.0%) had positive cell staining for CgA. No significant differences were found between the CgA-positive group and the CgA-negative group in age, prostate-specific antigen level, Gleason score, extent-of-disease grade, T stage, or N stage. The rate of freedom from recurrence after 2 years as analyzed by the Kaplan-Meier method was 18.2% for the CgA-positive group and 47.4% for the CgA-negative group, and the CgA-positive group had a significantly shorter time to recurrence (P < 0.0122). CONCLUSIONS: The results of our study have shown that patients with overexpression of CgA-positive cells in the prostate have a significantly shorter time to recurrence after hormonal therapy than patients with CgA-negative cells; thus, CgA expression may be a useful marker predictive of the time to recurrence.

Aged↗
PubMed2005

Measurements of several metallic elements and matrix metalloproteinases (MMPs) in saliva from patients with taste disorder.

We have measured and compared several metallic elements and matrix metalloproteinases (MMPs) in saliva from patients with taste disorder and healthy subjects. Stimulated whole saliva was collected from 20 patients and 35 healthy subjects. Inductively coupled plasma mass spectrometry (ICP-MS) was used for the determination of metallic elements in saliva. Amounts of MMP-1, MMP-3, MMP-9 and IL-1alpha, IL-6 in saliva were measured using an enzyme-linked immunosorbent assay systems. Zinc in the serum was determined by flame atomic absorption spectrometry. Our results provide evidence that levels of zinc, manganese and the amount of MMP-3 in saliva are significantly decreased in the patients with taste disorder compared to the healthy subjects; Zn (p.p.b.): healthy subjects 79.8 +/- 42.6, patients 47.22 +/- 17.1, (P < 0.001), Mn (p.p.b.): healthy subjects 4.48 +/- 2.46, patients 2.78 +/- 1.23, (P < 0.004), MMP-3 (ng/ml), healthy subjects 0.820 +/- 0.417, patients 0.594 +/- 0.179 (P < 0.01). In contrast, copper is significantly increased in the patients; Cu (p.p.b.): healthy subjects 34.5 +/- 13.5, patients 45.9 +/- 20.8 (P < 0.049). These differences may be closely related with this disease. ICP-MS is an easy and accurate instrument for measurements of salivary metallic elements and may be useful in establishing a diagnosis of taste disorder.

Aged↗