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Tatsuya Yamamoto

Publications and source records attributed to Tatsuya Yamamoto.

At least 19 recordsLinked to original sources
PubMed2006

Mechanism of constipation in familial amyloid polyneuropathy: a case report.

Previously no functional study has been available for the mechanism of constipation in familial amyloid polyneuropathy (FAP). We performed a gut function test in a 78-year-old woman with transthyretin-type FAP who had severe constipation. The gut function test showed a prolonged colonic transit time, a low anal pressure at rest and upon squeezing, loss of the spontaneous phasic rectal contractions, and weak abdominal strain. All these abnormalities suggested a peripheral autonomic dysfunction, corresponding to the enteric neuropathy that was confirmed upon autopsy.

Aged↗
PubMed2006

The location of brainstem neurons with bilateral projections to the motor nuclei of jaw openers in the cat.

Symmetrical motor output is the rule in the masticatory system. We examined morphologically how this functional symmetry might be reflected in the organization of premotor neurons that could mediate excitation of jaw-opener motoneurons. Premotor neurons projecting bilaterally to jaw-opener motoneurons by way of axon collaterals were identified by retrograde dual-labeling with cholera toxin B-conjugated fluorescein isothiocyanate (CTb-FITC) and tetramethylrhodamine (TMR). In each cat, CTb-FITC and TMR were injected into the digastric motoneuron pools, respectively, on the left and right sides. In three animals, 69-147 neurons were labeled with both tracers, comprising approximately 44% of all retrogradely labeled cells. Double-labeled cells were located bilaterally in the trigeminal oral nucleus (Vo) and the adjacent reticular formation (RF), the former containing a larger number of cells. Neurons labeled with only one tracer were also distributed bilaterally in the Vo and RF. The results indicated that the bilaterally projecting premoter neurons identified mainly in the Vo and RF represent neuronal substrates for the symmetry that characterizes most jaw movements.

Animals↗
PubMed2006

Mass spectrometry of hydrogen/deuterium exchange in 70S ribosomal proteins from E. coli.

The 70S ribosome from Escherichia coli is a supermacro complex (MW: 2.7MDa) comprising three RNA molecules and more than 50 proteins. We have for the first time successfully analyzed the flexibility of 70S ribosomal proteins in solution by detecting the hydrogen/deuterium exchange with mass spectrometry. Based on the deuterium incorporation map of the X-ray structure obtained at the time of each exchange, we demonstrate the structure-flexibility-function relationship of ribosome focusing on the deuterium incorporation of the proteins binding ligands (tRNA, mRNA, and elongation factor) and the relation with structural assembly processes.

Deuterium Exchange Measurement↗
PubMed2006

Incomplete emptying and urinary retention in multiple-system atrophy: when does it occur and how do we manage it?

Neurogenic urinary retention can be a major cause of morbidity in multiple-system atrophy (MSA). However, the timing of its appearance has not been entirely clear, and neither have the medical and surgical modalities for managing patients. We present the data obtained from our uroneurological assessment and therapeutic interventions at various stages of MSA. We recruited 245 patients with probable MSA. We measured postvoid residuals (PVR) and performed EMG cystometry in all patients. The grand average volume of PVR was 140 mL (range, 0-760) in our patients. The average PVR volume was 71 mL in the first year, increasing to 129 mL in the second year and 170 mL by the fifth year. The percentages of patients with complete urinary retention, acontractile detrusor, and detrusor-sphincter dyssynergia (DSD) also increased. The increase in PVR resulted in a decrease in functional bladder capacity, together with an increase in detrusor overactivity and neurogenic sphincter EMG. Clean intermittent self-catheterization (CISC) was introduced in most patients. Bladder-oriented therapy (cholinergic agents) had a limited value, whereas urethra-oriented therapy benefited patients with DSD (surgery) for up to 2 years, but syncope occurred in a subset of patients (alpha-blockers). MSA patients present with large PVR by the second year of illness, and that large PVR secondarily causes urinary frequency. CISC is the recommended treatment for most patients. Urethra-oriented medication and surgery benefit patients who would have difficulty performing CISC, although careful consideration of the short-term efficacy and potential adverse effects of these alternatives is mandatory.

Adrenergic alpha-Antagonists↗
PubMed2006

Neurological diseases that cause detrusor hyperactivity with impaired contractile function.

AIMS: Detrusor hyperactivity with impaired contractile function (DHIC) was originally described in elderly women. It has not previously been well known whether neurological diseases cause DHIC. We investigated which neurological diseases commonly cause DHIC in our laboratory. MATERIALS AND METHODS: We searched for DHIC in our laboratory's computerized database of 1,514 case records, which included a lower urinary tract (LUT) symptom questionnaire and urodynamic study results. DHIC was defined as the presence of both (1) detrusor overactivity during the storage phase, and (2) underactive detrusor contraction during the evacuation phase. RESULTS: Two hundred and seventeen patients met the criteria for DHIC: 122 men and 95 women; mean age, 63 years. The neurological diseases that caused DHIC included Parkinsonian syndrome (18%), multiple system atrophy (18%), progressive supranuclear palsy/corticobasal degeneration (14%), multiple cerebral infarction (MCI) (12%), multiple sclerosis/acute disseminated encephalomyelitis (18%), spinal cord lesions (15%), and cervical spondylotic myelopathy (CS) (10%). CONCLUSIONS: The present study revealed that a wide spectrum of neurological disorders could cause DHIC.

Adult↗
PubMed2006

Bladder sensation in peripheral nerve lesions.

OBJECTIVE: To present bladder sensory data of three common peripheral nerve lesions (e.g., distal, intermediate/focal, and proximal). METHODS: We measured first sensation (FS) and bladder capacity (BC) (not exceeding 600 ml) in 71 patients with peripheral nerve lesions: 35 diabetic neuropathy (D group), 6 post-pelvic surgery (S), and 27 cauda equina syndrome due to lumbar spondylosis (L). We excluded those with detrusor overactivity or low compliance that might affect bladder sensation. RESULTS: The mean FS was 301.7 ml (D), 271.3 ml (S), and 189.4 ml (L), with the largest being in the D group (P < 0.05); the mean BC was 495.2, 475.4, and 391.4 ml, with the largest being in the D group (P < 0.05); who commonly had less frequent toileting. The mean post-void residual volume was 106.5, 29.0, and 42.0 ml; the values tended to increase along with BC. In the D group, the mean FS in patients with skin hypoalgesia as detected by pin prick and in those without it was 407.8 and 210.0 ml. The percentage of patients with FS < 100 ml was 5.7%, 0%, and 7.4%, respectively, who commonly had urinary urgency and frequency. CONCLUSIONS: Bladder sensation is affected in diabetic neuropathy more severely than in intermediate/proximal lesions, together with somatic sensory disturbance. Bladder sensory disturbance leads to less frequent toileting, resulting in bladder over-distension and large post-void residuals. A small proportion of patients with peripheral nerve lesions develop urinary urgency, presumably reflecting irritation of the afferent nerve fibers or the urothelium.

Aged↗
PubMed2006

Urinary dysfunction and autonomic control in amyloid neuropathy.

Uro-neurological assessment was performed in four patients with small-fiber neuropathy due to amyloidosis (2 transthyretin-type/2 immunoglobulin light-chain-type). Voiding difficulties were due to detrusor weakness and impaired bladder sensation. In two patients cholinesterase inhibition treatment caused urge incontinence, indicating detrusor denervation supersensitivity. The underlying mechanisms of urinary dysfunction seem to involve postganglionic cholinergic and afferent somatic nerves.

Aged↗
PubMed2006

Videomanometry of the pelvic organs: a comparison of the normal lower urinary and gastrointestinal tracts.

BACKGROUND: Both the lower urinary tract (LUT) and the caudal part of the lower gastrointestinal tract (LGIT) are innervated by the sacral spinal cord. We aimed to compare the normal physiology of the LUT and LGIT using the same videomanometry method. METHODS: We recruited fifteen healthy volunteers (eight men and seven women; mean age, 60 years). The videomanometric measures included fluoroscopic images, subtracted bladder/rectal pressures, urethral/anal sphincter pressures, sphincter electromyography, and urinary/fecal flow. RESULTS: During the resting phase, the urethral/anal sphincter pressures showed almost the same values (mean, 70 cmH2O and 68 cmH2O, respectively). During the storage phase, the volumes at first sensation and maximum capacity for the LGIT (129 mL and 320 mL) were slightly smaller than those for the LUT (170 mL and 405 mL). Compliance of the LGIT (65 mL/cmH2O) was almost as high as that of the LUT (99 mL/cmH2O). However, the LGIT showed spontaneous phasic rectal contractions (SPRC) that were never seen in the bladder. None of the subjects experienced leakage during bladder/rectal filling. During the evacuation phase, rectal contraction on defecation (14 cmH2O) was present, but was weaker than bladder contraction on micturition (42 cmH2O; P < 0.01). Abdominal strain on defecation (70 cmH2O) was greater than that on micturition (25 cmH2O; P < 0.01). Sphincter pressure increase on defecation (13 cmH2O) was greater than that on micturition (-52 cmH2O). An illustrative case of SPRC that were seen during urodynamic recording was shown. CONCLUSION: SPRC and abdominal strain are features of the LGIT, whereas micturition bladder contraction is a feature of the LUT. These features can aid in understanding the possible rectal 'artifacts' of videourodynamics and neurogenic pelvic organ dysfunction.

Adult↗
PubMed2005

Gene expression and localization of insulin-like growth factors and their receptors throughout amelogenesis in rat incisors.

Insulin-like growth factors (IGFs) are expressed in many tissues and control cell differentiation, proliferation, and apoptosis. In teeth, the temporo-spatial pattern of expression IGFs and their receptors has not been fully characterized. The purpose of this study was to obtain a comprehensive profile of their expression throughout the life cycle of ameloblasts, using the continuously erupting rat incisor model. Upper incisors of young male rats were fixed by perfusion, decalcified, and embedded in paraffin. Sections were processed for in situ hybridization and immunohistochemistry. mRNA and protein expression profiles IGF-I, IGF-II, IGF-IR, and IGF-IIR mRNA were essentially identical. At the apical loop of the incisor, very strong signals were seen in the outer enamel epithelium while the inner enamel epithelium showed a moderate reaction. In the region of ameloblasts facing pulp, inner enamel epithelium cells were still moderately reactive while signals over the outer enamel epithelium were slightly reduced. In the region of ameloblasts facing dentin and the initial portion of the secretory zone, signals in ameloblasts were weak while those over the outer enamel epithelium were strong. In the region of postsecretory transition, signals in both ameloblasts and papillary layer cells gradually increased. In maturation proper, signals in ameloblasts appeared as alternating bands of strong and weak reactivities, which corresponded to the regions of ruffle-ended and smooth-ended ameloblasts, respectively. Papillary layer cells also showed alternations in signal intensity that matched those in ameloblasts. These results suggest that the IGF family may act as an autocrine/paracrine system that influences not only cell differentiation but also the physiological activity of ameloblasts.

Amelogenesis↗
PubMed2005

Meningitis-retention syndrome. An unrecognized clinical condition.

BACKGROUND: A combination of acute urinary retention and aseptic meningitis has not been well known. This combination can be referred to as meningitis-retention syndrome (MRS), when accompanied by no other abnormalities. OBJECTIVE: To describe the results of a uro-neurological assessment in our patients with MRS. METHODS: In three patients (two men, one woman; age, 34-68 years), we performed urodynamic studies and relevant imaging and neurophysiological tests, in addition to cerebrospinal fluid (CSF) examination. RESULTS: All three patients developed acute urinary retention along with headache, fever and stiff neck. None had obvious neurological abnormalities, other than a slightly brisk reflex in the lower extremities. One had previously experienced generalized erythematous eruptions, but none had pain, hypalgesia or skin eruptions in the sacral dermatomes suggestive of Elsberg syndrome (infectious sacral polyradiculitis; mostly genital herpes). Brain/spinal/lumbar plexus MRI scans and nerve conduction studies were normal. CSF examination showed mild mononuclear pleocytosis, increased protein content, and normal to mildly decreased glucose content in all patients; increased myelin basic protein suggestive of central nervous system demyelination in one; and increased viral titers in none. Urodynamic study revealed, during the voiding phase, an underactive detrusor in all patients and an unrelaxing sphincter in one. These clinical manifestations were ameliorated within 3 weeks. CONCLUSIONS: We reported three cases of MRS, a peculiar syndrome that could be regarded as a mild variant of acute disseminated encephalomyelitis (ADEM). Urinary retention might reflect acute shock phase of this disorder. Although MRS has a benign and self-remitting course, management of the acute urinary retention is necessary.

Adult↗