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Biomedical subjects

R Sakakibara

Publications and source records attributed to R Sakakibara.

At least 19 recordsLinked to original sources
PubMed2006

Urinary retention can be the sole initial manifestation of acute myelitis.

Urinary retention is a frequent feature in patients with acute myelitis (AM). We here describe the result of a survey of 32 consecutive AM patients as to what extent of AM patients initially present with micturition disturbance. Among those, 3 patients (9%) were shown to have urinary retention as the initial sole manifestation, which was followed by dysesthesia of foot in 3 and leg weakness in 1; and the average interval between micturition disturbance and these second-appearing symptoms/signs was 11 days (8-15 days). Although initial presentation of urinary retention was not common, occurring in only 9% of all the AM patients, clinically it has relevance because patients who suffer urinary retention but have no obvious neurological symptoms may first see general physicians or urologists. In those patients, when obstructive disease has been excluded, AM should be considered.

Acute Disease↗
PubMed2006

Effects of electrical stimulation of the raphe area on the micturition reflex in cats.

The raphe nucleus has a variety of physiological functions, including emotion, regulation of skeletal muscle motoneurons, spinal transmission of nociceptive signals, sleep, respiration, gastric motility, and cardiovascular function. Recent evidence has shown that centrally administered serotonin has modulatory effects on micturition function, and that decreased brain serotonin might underlie depression and an overactive bladder. We applied high-frequency stimulation (HFS; 0.2-ms duration, 100 Hz) in the raphe nucleus and the adjacent midline area in 20 supracollicular decerebrate cats, which mostly elicited inhibition of the micturition reflex. The effective amplitude of the electrical stimulation for evoking inhibitory responses was less than 50 muA. We also examined single neuronal activities in the raphe nucleus in response to isovolumetric spontaneous micturition reflexes. In total, 79 neurons were recorded in the raphe nucleus that were related to urinary storage/micturition cycles. Of the neurons recorded, the most common were tonic storage neurons (48%), followed by tonic micturition neurons (28%), phasic storage neurons (18%), and phasic micturition neurons (6%). In addition to the tonic/phasic as well as storage/micturition classification, the neurons showed diverse discharge patterns: augmenting, constant and decrementing, with the constant discharge pattern being most common. Among neurons in the raphe nucleus, the neurons with a decrementing discharge pattern were concentrated in the rostral portion, whereas the augmenting and constant neurons existed diffusely. The storage and micturition neurons were intermingled in the rostral portion, whereas they were separate in the caudal portion. In conclusion, the results of the present study indicate that HFS of the raphe area inhibits the micturition reflex and that there are micturition-related neuronal firings in the raphe area in cats, suggesting that the raphe nucleus is involved in neural control of micturition.

Action Potentials↗
PubMed2005

Striatal dopamine level increases in the urinary storage phase in cats: an in vivo microdialysis study.

Parkinson's disease is a common neurodegenerative disease that shows not only movement disorder, but also profound urinary dysfunction. Bladder hyperactivity is the major urodynamic abnormality. Therefore, the basal ganglia have been thought to modulate the micturition reflex. In six male adult cats under ketamine anesthesia, in which spontaneous isovolumetric micturition reflexes had been generated, we measured levels of striatal dopamine, in micturition and storage phases, using in vivo microdialysis. The striatal dopamine level significantly increased in the storage phase as compared with that in the micturition phase. It is suggested that striatal dopamine may inhibit the micturition reflex via the dopamine D1 receptor-GABAergic direct striatal output pathway, and that disruption of this pathway may be what leads to bladder hyperactivity in patients with Parkinson's disease.

Animals↗
PubMed2005

Post-micturitional hypotension in patients with multiple system atrophy.

BACKGROUND: Patients with multiple system atrophy (MSA) occasionally have episodes of syncope or pre-syncope after micturition. OBJECTIVE: To clarify the mechanism of these episodes by investigating the haemodynamic changes associated with micturition. METHODS: 25 patients with probable MSA and 16 age matched normal controls were studied. Continuous records of blood pressure and heart rate were made during water cystometry, along with the Valsalva manoeuvre, head up tilt testing, measurement of plasma noradrenaline, and calculation of coefficient of variance of RR intervals. RESULTS: Compared with normal controls, MSA patients had a lower baseline blood pressure, smaller blood pressure and heart rate increases during bladder filling, and an abnormal fall in blood pressure for a longer duration after voiding, resulting in significantly lower blood pressure than at baseline (mean systolic blood pressure reduction -15.2 mm Hg), and hypotension compared with control blood pressure (-29.0 mm Hg). The blood pressure fall was greater in patients with micturition syncope/pre-syncope than in those without. It was also greater in patients with abdominal straining resulting from difficulty in voiding. Other cardiovascular indices did not correlate with the fall in blood pressure. CONCLUSIONS: Hypotension after voiding in MSA patients may result from generalised autonomic dysfunction and abnormal abdominal straining, resulting in micturition syncope.

Aged↗
PubMed2005

Lower urinary tract function in patients with pituitary adenoma compressing hypothalamus.

BACKGROUND: The micturition reflex is under the tonic influence of suprapontine structures including the anteromedial frontal cortex, basal ganglia, and hypothalamus. However, there have been few reports about the role of the hypothalamus on the lower urinary tract (LUT) function in humans. OBJECTIVE: To investigate LUT function in patients with pituitary adenomas. METHODS: Urodynamic studies were carried out in three patients with LUT symptoms who had pituitary adenomas extending upwards to the hypothalamus. RESULTS: All three male patients (age 28 to 62 years) developed LUT symptoms (urinary urgency and frequency (3); urinary incontinence (3); voiding difficulty and retention (2)) along with weight loss, psychiatric symptoms, unsteady gait, and/or visual disturbances. One had the syndrome of inappropriate secretion of antidiuretic hormone, but none had diabetes insipidus. Two had resection of the tumour and subsequent radiation therapy, but LUT dysfunction persisted. The third patient had partial resection of the tumour to ameliorate hydrocephalus. Urodynamic studies showed detrusor overactivity during the storage phase in all patients; during the voiding phase there was underactive detrusor in two and non-relaxing sphincter in one. CONCLUSIONS: Hypothalamic lesions can cause severe LUT dysfunction in both the storage and voiding phases of micturition. This may reflect the crucial role of the hypothalamus in regulating micturition in humans.

Adenoma↗
PubMed2005

Lower urinary tract function in dementia of Lewy body type.

OBJECTIVE: Dementia of Lewy body (DLB) type is the second commonest degenerative cause of dementia and autonomic dysfunction has been recognised in DLB. Lower urinary tract (LUT) function in DLB has not been fully delineated. We investigated LUT function in DLB by evaluating clinical and urodynamic data. METHODS: We examined 11 patients (eight men, three women; age range 65-81; disease duration 2-14 years) with probable DLB. Urodynamic studies consisted of: measurement of postvoid residual in all patients, uroflowmetry in five, and electromyography (EMG) cystometry in seven. RESULTS: All patients had symptoms of LUT: urinary incontinence (urgency type/functional type due to dementia and immobility/both urgency and stress type in 7/2/1 patients, respectively); night-time frequency; urgency; and daytime frequency and voiding difficulty. Seven had postvoid residuals, and three had residual urine volume >100 ml. Decreased urinary flow was seen in all five and detrusor overactivity in 5/7 patients who underwent flowmetry and EMG cystometry, respectively. Low compliance detrusor (storage phase, n = 2; with bethanechol supersensitivity), an underactive detrusor (n = 4), an acontractile detrusor (n = 1), and detrusor-sphincter dyssynergia (voiding phase) (n = 1) were also seen; 2/3 patients who underwent motor unit potential analysis had neurogenic changes. CONCLUSION: LUT dysfunction is a common feature in DLB, not only due to dementia and immobility, but also to central and peripheral types of somato-autonomic dysfunction.

Aged↗
PubMed2005

When is Onuf's nucleus involved in multiple system atrophy? A sphincter electromyography study.

BACKGROUND: External anal sphincter (EAS) electromyography (EMG) abnormalities can distinguish multiple system atrophy (MSA) from Parkinson's disease in the first five years after disease onset. However, the prevalence of the abnormalities in the early stages of MSA is unknown. OBJECTIVES: To present EAS-EMG data in the various stages of MSA. METHODS: 84 patients with "probable" MSA were recruited (42 men, 42 women; mean age 62 years (range 47 to 78); mean disease duration 3.2 years (0.5 to 8.0; <1 year in 25%); 50 cerebellar form (MSA-C), 34 parkinsonian form (MSA-P)). EAS motor unit potential (MUP) analysis and EMG cystometry were carried out in all patients. RESULTS: The overall prevalence of neurogenic change of the EAS MUP was 62%-52% in the first year after disease onset, increasing to 83% by the fifth year (p<0.05); it also increased with severity of gait disturbance (p<0.05), storage and voiding disorders, and detrusor sphincter dyssynergy (NS). The neurogenic change was not correlated with sex, age, MSA-P/C, postural hypotension, constipation, erectile dysfunction in men, underactive or acontractile detrusor, or detrusor overactivity. In 17 incontinent patients without detrusor overactivity or low compliance, urinary incontinence was more severe in those with neurogenic change than in those without (p<0.05). CONCLUSIONS: Involvement of Onuf's nucleus in MSA is time dependent. Before the fifth year of illness, the prevalence of neurogenic change does not seem to be high, so a negative result cannot exclude the diagnosis of MSA.

Aged↗
PubMed2004

Observation of millimeter-wave radiation generated by the interaction between an electron beam and a photonic crystal.

We observed directional light emission in the millimeter-wave region when a high-energy (150 MeV) electron beam passes just above a photonic crystal made of polytetrafluoroethylene beads ( approximately 3.2 mm in diameter). The relation between the momentum and the energy of the emitted photons strongly suggests that the observed light is generated by the umklapp scattering process that changes the evanescent waves emitted by the electron beam into observable ones. By comparing the observed spectra with calculated ones based on the photonic band structure, we found that generated photons excite the photonic band modes making them observable as enhanced fine structures in the emission spectra.

Journal Article↗
PubMed2004

Micturition-related neuronal firing in the periaqueductal gray area in cats.

The midbrain periaqueductal gray (PAG) is the area promoting emotional motor responses, reproductive behaviors and analgesia. Recent studies suggest that neurons in the PAG may be crucial for regulating the micturition reflex in both experimental animals and humans. We examined single neuronal activities in the PAG and the adjacent area in response to isovolumetric spontaneous micturition reflexes in 20 supracollicular decerebrated cats. In total, 84 neurons were recorded in the PAG that were related to urinary storage/micturition cycles. Of the neurons recorded, the most common were tonic storage neurons (43%), followed by tonic micturition neurons (29%), phasic storage neurons (15%) and phasic micturition neurons (13%). In addition to the tonic/phasic as well as storage/micturition classification, the neurons showed diverse discharge patterns: augmenting, constant and decrementing, with the constant discharge pattern being most common. Of the 16 neurons located within the PAG that had similar discharge patterns to those just ventral to the PAG, the micturition neurons were distributed in a broader area, whereas the storage neurons seemed to be concentrated in the middle part of the PAG (P0-1, Horsley-Clarke coordinate). High-frequency stimulation (HFS; 0.2-ms duration, 100 Hz) applied in the PAG elicited inhibition of the micturition reflex. Effective amplitude of the electrical stimulation for evoking inhibitory responses was less than 50 microA. In conclusion, the results of the present study showed that HFS of the PAG inhibited the micturition reflex and there were micturition-related neuronal firings in the PAG in cats, suggesting that the PAG is involved in neural control of micturition.

Action Potentials↗
PubMed2004

Primary Sjogren's syndrome presenting with generalized autonomic failure.

A 64 year-old woman developed Raynaud's phenomenon and dry eyes/mouth. Laboratory examination revealed positive Schirmer's test, rheumatoid factor and anti-nuclear antibody, and lymphocytic sialoadenitis on salivary gland biopsy. These features strongly suggested the diagnosis of primary Sjogren's syndrome. Three years later, she gradually developed generalized autonomic failure without apparent sensory neuropathy on nerve conduction study. She had systolic pressure fall of 51 mmHg on head-up tilt test, cardiovascular supersensitivity to diluted norepinephrine infusion, cardiac denervation in [123I]-MIBG scintigraphy, impaired R-R variability, decreased sweating and prolonged colonic transit time. Autoimmune autonomic ganglionopathy was mostly responsible for her autonomic failure.

Cardiovascular Diseases↗
PubMed2004

Reduced cerebellar vermis activation during urinary storage and micturition in multiple system atrophy: 99mTc-labelled ECD SPECT study.

Single-photon emission computed tomography brain imaging with special reference of bladder function was performed in eight multiple system atrophy (MSA) patients (two men, six women; mean age, 61 years) and age-matched five normal control subjects (three men, two women; 62 years). In both groups imagings were obtained in three conditions; empty bladder, storage, and micturition. [99mTc]-labelled ECD (555 MBq) was intravenously injected, which was immediately trapped and stabilized within the brain. Using NEUROSTAT software, which could also cancel morphologic differences between MSA and canonical brain, statistical difference between normalized mean tracer counts of both groups in each phase was calculated and visualized. In the storage phase, there was a significant decrease in tracer activity in bilateral cerebellar vermis, particularly of the right side in the MSA group (P < 0.05), which is also known to be involved in the neural control of micturition. In the micturition phase, the area of decrease in tracer activity in the cerebellar vermis became wider in the MSA group. In the resting state, no statistically significance was seen between both groups. In conclusion, it is suggested that the decrease in tracer activity in the cerebellar vermis during urinary storage and micturition is contributing to the micturitional disturbance in this disorder.

Aged↗
PubMed2004

Micturition disturbance in acute idiopathic autonomic neuropathy.

OBJECTIVE: To define the nature of micturition disturbance in patients with acute idiopathic autonomic neuropathy (AIAN). METHODS: Micturitional symptoms were observed during hospital admissions and the in outpatient clinics in six patients with clinically definite AIAN (typical form in four, cholinergic variant in one, autonomic-sensory variant in one). Urodynamic studies included medium-fill water cystometry, external sphincter electromyography, and a bethanechol test. RESULTS: Four patients had urinary retention and two had voiding difficulty as the initial presentation. Patients with retention became able to urinate within a week (two to seven days). The major symptoms at the time of urodynamic studies (three weeks to four months after disease onset in most cases) were voiding difficulty and nocturnal frequency. None had urinary incontinence. Complete recovery from the micturition disturbance took from three months to >18 years. The recovery period was shorter in a patient with cholinergic variant, and it was longer in two patients who had a longer duration of initial urinary retention. Micturition disturbance tended to improve earlier than orthostatic hypotension. The major urodynamic abnormalities were detrusor areflexia on voiding (5), denervation supersensitivity to bethanechol (3); low compliance detrusor (1); and impaired bladder sensation (2). None had neurogenic motor unit potentials of the external sphincter muscles. CONCLUSIONS: In patients with AIAN, urinary retention and voiding difficulty are common initial presentations. The underlying mechanisms seem to be pre- and postganglionic cholinergic dysfunction with preservation of somatic sphincter function. The bladder problems tend to improve earlier than orthostatic hypotension.

Acute Disease↗