Search PubMed⌕ Search

Biomedical subjects

A Hiraga

Publications and source records attributed to A Hiraga.

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↗
PubMed2005

Recruitment pattern of muscle fibre type during high intensity exercise (60-100% VO2max) in thoroughbred horses.

To consider the optimal training programme for Thoroughbred horses, we examined the recruitment pattern of muscle fibres including hybrid muscle fibres in well-trained Thoroughbred horses. The horses performed exercise at three different intensities and durations; i.e., 100% VO2max for 4 min, 80% and 60% VO2max for 8 min on a treadmill with 10% incline. Muscle samples were obtained from the middle gluteal muscle before, during (4 min at 80% and 60% VO2max), and after exercise. Four muscle fibre types (types I, IIA, IIA/IIX, and IIX) were immunohistochemically identified, and optical density of periodic acid Schiff staining (OD-PAS) in each fibre type, and the glycogen content of the muscle sample, were determined by quantitative histochemical and biochemical procedures. The changes in OD-PAS showed that the recruitment of all fibre types were identical at the final time stage of each exercise bout, i.e., 4 min running at 100% VO2max, and 8 min running at 80% and 60% VO2max. The changes in OD-PAS of type IIA/IIX fibre were very similar to those of type IIX fibre. The recruitment of these fibres were obviously more facilitated by 4 min running at 100% VO2max than by 4 min running at 80% or 60% VO2max. Short duration with high intensity exercise, such as 4 min running at 100% VO2max or 8 min running at 80% or 60% VO2max, is effective to stimulate type IIX fibre and IIA/IIX fibres that have the fastest speed of contraction.

Animals↗
PubMed2005

Patterns and serial changes in electrodiagnostic abnormalities of axonal Guillain-Barré syndrome.

BACKGROUND: In Guillain-Barré syndrome (GBS), anti-ganglioside antibodies are strongly associated with the acute motor axonal neuropathy (AMAN) form, but there are also cases of the demyelinating form of GBS (acute inflammatory demyelinating polyneuropathy [AIDP]) with anti-ganglioside antibodies. OBJECTIVE: To elucidate the patterns and sequential changes in electrodiagnostic abnormalities of anti-ganglioside-positive GBS. METHODS: Detailed serial electrodiagnostic findings were reviewed for 51 patients with GBS. Anti-ganglioside antibodies were measured by ELISA. RESULTS: Antibodies to GM1, GM1b, GD1a, or GalNAc-GD1a were present in 25 patients. Of these, 12 (48%) showed the AMAN pattern, 5 (20%) the AIDP pattern, and 3 (12%) isolated F-wave absence in the first examination. All five patients with the AIDP pattern showed prolonged distal latencies, but three eventually showed the AMAN pattern or rapid normalization. The remaining two still had similarly prolonged distal latencies in weeks 4 to 6, but the serial changes were distinct from those in the anti-ganglioside-negative AIDP patients who showed progressive increases in distal latencies over 2 months after onset. CONCLUSIONS: Besides the simple axonal degeneration pattern, patients with anti-ganglioside-positive Guillain-Barre syndrome can show transient conduction slowing/block in the distal or proximal nerve segments, mimicking demyelination, but anti-ganglioside antibodies do not appear to be associated with acute inflammatory demyelinating polyneuropathy.

Adult↗
PubMed2005

Recovery patterns and long term prognosis for axonal Guillain-Barré syndrome.

BACKGROUND: Little is known about the long term prognosis for patients the severe acute motor axonal neuropathy (AMAN) form of Guillain-Barré syndrome (GBS), unlike those with acute inflammatory demyelinating neuropathy (AIDP). OBJECTIVE: To clarify the long term prognosis for patients with AMAN. METHODS: Clinical recovery and outcome in 97 consecutive GBS patients were reviewed. RESULTS: Electrodiagnostic criteria showed that 44 patients (45%) had AMAN, 33 (34%) had AIDP, and 20 (21%) were unclassified. Most of the severely affected patients had received plasmapheresis or immunoglobulin therapy. Slow recovery (inability to walk independently at six months after onset) was found in six of the AMAN patients (14%) and in two of the AIDP patients (6%). Of the six AMAN patients, four could walk independently one year after the onset, and the other two could walk independently at 28 and 57 months after onset. Of the two AIDP patients, one could walk at nine months after the onset while the other died of pneumonia seven months after onset. CONCLUSIONS: AMAN electrodiagnosis is not always a marker of poor recovery. Almost all the severe AMAN patients who had slow recoveries over the first six months could eventually walk independently, although some required several years.

Adolescent↗
PubMed2004

Does Campylobacter jejuni infection elicit "demyelinating" Guillain-Barre syndrome?

BACKGROUND: Campylobacter jejuni enteritis is the most common antecedent infection in Guillain-Barré syndrome (GBS). C. jejuni-related GBS is usually acute motor axonal neuropathy (AMAN), but previous reports described many cases of the demyelinating subtype of GBS (acute inflammatory demyelinating polyneuropathy [AIDP]) after C. jejuni infection. OBJECTIVE: To investigate whether C. jejuni infection elicits AIDP. METHODS: In 159 consecutive patients with GBS, antibodies against C. jejuni were measured using ELISA. Antecedent C. jejuni infection was determined by the strict criteria of positive C. jejuni serology and a history of a diarrheal illness within the previous 3 weeks. Electrodiagnostic studies were performed weekly for the first 4 weeks, and sequential findings were analyzed. RESULTS: There was evidence of recent C. jejuni infection in 22 (14%) patients. By electrodiagnostic criteria, these patients were classified with AMAN (n = 16; 73%) or AIDP (n = 5; 23%) or as unclassified (n = 1) in the first studies. The five C. jejuni-positive patients with the AIDP pattern showed prolonged motor distal latencies in two or more nerves and had their rapid normalization within 2 weeks, eventually all showing the AMAN pattern. In contrast, patients with cytomegalovirus- or Epstein-Barr virus-related AIDP (n = 13) showed progressive increases in distal latencies in the 8 weeks after onset. CONCLUSION: Patients with C. jejuni-related Guillain-Barré syndrome can show transient slowing of nerve conduction, mimicking demyelination, but C. jejuni infection does not appear to elicit acute inflammatory demyelinating polyneuropathy.

Adolescent↗
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↗
PubMed2003

Differences in patterns of progression in demyelinating and axonal Guillain-Barré syndromes.

BACKGROUND: Immune treatments are recommended for patients with Guillain-Barré syndrome (GBS) who cannot walk independently, but a considerable number of GBS patients are in the progressive phase at the first examination. OBJECTIVE: To investigate whether progression patterns differ in demyelinating and axonal subtypes of GBS. METHODS: Clinical, laboratory, and electrophysiologic data on 131 consecutive patients with GBS were reviewed. Patients were classified as having acute inflammatory demyelinating polyneuropathy (AIDP) or acute motor axonal neuropathy (AMAN) based on electrodiagnostic criteria. RESULTS: Forty-one patients had AIDP, 62 AMAN, and 28 were unclassified. Age, sex, and Hughes Functional Grading Scale score at the first medical examination did not differ for the AIDP and AMAN patients. Mean periods between neurologic onset and first examination (5.3 vs 4.2 days; p = 0.01) and neurologic onset and nadir (18.0 vs 11.5 days; p = 0.001) were longer for the AIDP group. In the subgroup of those with mild disability (able to walk independently at the first neurologic examination), 88% of the AMAN patients had reached the nadir, whereas 65% of the AIDP patients had reached it. The remaining 35% progressed to it over the next 1 to 2 weeks and were unable to walk at nadir. CONCLUSIONS: The patterns and speeds of progression differ in AMAN and AIDP, AMAN having a rapid progression and an early nadir. AIDP patients frequently have a significantly long progression after the first examination; therefore, they need to be carefully monitored.

Acute Disease↗
PubMed2003

Effects of novelty stress on neuroendocrine activities and running performance in thoroughbred horses.

This study investigated the effects of novelty stress on neuroendocrine activities and running performance in Thoroughbred horses. First, to examine the neuroendocrine responses to novelty stress, we exposed horses to two types of novel environmental stimuli (audiovisual or novel field stimuli). After the stimuli, plasma concentrations of vasopressin, catecholamines and adrenocorticotropin (ACTH), as well as heart rates, were significantly increased in each experiment. Second, we investigated neuroendocrine activities during incremental exercise. Plasma concentrations of vasopressin, catecholamines, ACTH and blood lactate increased as the exercise load increased. Finally, we investigated the effects of novelty stimuli on neuroendocrine activities and running performance during supra-maximal exercise (110% VHRmax). When the novelty stimuli were presented to horses, the increases in plasma vasopressin and catecholamines due to exercise load were significantly smaller than those in the control experiments. Blood lactate during supra-maximal exercise was also significantly lower and total run time until exhaustion was prolonged in the novel environmental stimuli compared to the control. These results suggest that novelty stimuli facilitate vasopressin release from the posterior pituitary in addition to activating the sympatho-adrenomedullary and the hypothalamic-pituitary-adrenocortical axes in thoroughbred horses, and increase exercise capacity, resulting in improvement of running performance during supra-maximal exercise.

Adrenocorticotropic Hormone↗
PubMed2003

[Report on the ECR2003 (European Congress of Radiology): comparison of apparent diffusion coefficient (ADC) between different MRI scanners].

PURPOSE: To analyze reproducibility of ADC measurements on different MRI scanners. METHODS AND MATERIALS: Diffusion-weighted imaging (DWI) of a home-made phantom (gelatine of different concentration was enclosed in case of circle pillar shape) was performed with the following protocol; spin-echo type echo planar imaging; TR=7000 msec, TE=minimal, matrix=128 x 128, FOV=220 mm, slice thickness=5mm, NEX=1, b-factor=0, 500, and 1000 sec/mm(2) on four different 1.5T MR scanners [GE Signa Horizon (two of them), GE Signa Horizon Lx, and Siemens Magnetom Symphony]. Image analysis were performed on a workstation (GE Medical Systems) or on an operators console of Symphony (for data of Symphony). We used two-point method. Regions of interest (ROIs) were set on every part of ADC map of home-made phantom and ADCs were measured. A linear approximation graphs were also made with every MRI scanner and b-factor. RESULTS: A linear approximation was performed, formulas were y=-0.08x+2.32, r(2)=0.84(Lx), y=-0.09x+2.58, r(2)=0.89(Horizon-1) y=-0.11x+2.67, r(2)=0.95(Horizon-2), y=-0.08x+2.42, r(2)=0.97(Symphony) at b-factor of 500sec/mm(2). y=-0.08x+2.33, r(2)=0.91(Lx), y=-0.09x+2.43, r(2)=0.93(Horizon-1), y=-0.08x +2.48, r(2)=0.92(Horizon-2), y=-0.07x+2.39, r(2)=0.96(Symphony) at b-factor of 1000 sec/mm(2). CONCLUSIONS: ADC values measured at two MRI scanners (same model and older than the other scanners) are higher than other scanners on b-factor=500 sec/mm(2), but at b-factor=1000 sec/mm(2), a good relationship between every scanners was obtained. This result seems to depend on generation of the MRI scanners; newly scanners have good relations b-factor 500 and 1000 sec/mm(2). Pulse sequence design may be improved and optimized in newly scanners. When ADCs were used as quantitative value, a proper b-factor must be used.

Diffusion Magnetic Resonance Imaging↗
PubMed2002

Physiological responses of young Thoroughbreds during their first year of race training.

Yearling horses are typically trained for more than a year before they begin racing; therefore, we questioned how relevant analyses of the initial responses to training are compared to physiological responses that occur over a year of training, and whether young horses with no history of training would respond the same as older horses that had been trained previously. We hypothesised that changes in O2 transport over the last months of a year of training would be different than at the beginning. We trained 5 yearling Thoroughbreds and evaluated metabolism, O2 transport and echocardiograms. Measurements were made before breaking (T1), after 6 months of training (T2) and following an additional 4 months of training (T3). We compared 5 trained horses (TR) with 5 untrained (UT) sex-, size- and age-matched yearlings kept at pasture and in boxes. Satellite telemetry indicated UT moved less total daily distance than TR during winter and more during summer, but UT walked for 80% of their distance, TR only 25%. The UT increased body mass (Mb) after T1 by 13% and were significantly heavier and fatter than TR. Specific aerobic capacity (VO2max/Mb) increased by 16% in both groups at T2, but by T3 was not different from T1 in UT, but was higher in TR (19%>T1, 15%>UT). In TR, specific cardiac output (Q/Mb) increased by 13% at T2, and specific stroke volume (V(S)/Mb) were larger at T2 and T3 than T1 and UT at the same times both by physiological (15-16%) and echocardiographical (22-23%) estimates. Increased Vs was a primary correlate of the sustained increase in VO2max/Mb in TR. The large increases in V(S) and VO2max had occurred by T2 and changed only slightly by T3.

Aging↗
PubMed2002

Heterogeneity of intrapleural pressures during exercise.

We determined whether the caudodorsal region of the intrapleural space in exercising horses experiences larger pressure fluctuations than other regions and whether systematic phase-shifting of peak intrapleural pressures along the length of the thorax suggests the existence of locomotor-induced intrapleural pressure waves. We utilised percutaneous introducers and solid-state pressure-tip transducers implanted along the dorsal aspect of the thorax, mid-thorax or oesophagus to measure regional intrapleural pressures while 3 horses galloped on a flat treadmill at 13-14 m/s, then recorded pressures from the same catheters when horses exercised intensely (heart rate 170-190 beats/min) while swimming with no ground concussion. Pressure excursions in the caudodorsal region did not vary systematically from other regions during galloping or swimming, nor more than a few torr between different locations. During swimming, peak expiratory pressures were higher than during galloping (68-79 vs. 26-32 torr), and horses breathed explosively at frequencies 5 times slower than while galloping (28 vs. 120/min). During galloping, individual catheter locations registered locomotor concussion; however, this was variable and did not indicate a systematic pressure wave passing through the lung or intrapleural space.

Animals↗
PubMed2001

Dynamic micro-magnetic resonance imaging of liver micrometastasis in mice with a novel liver macromolecular magnetic resonance contrast agent DAB-Am64-(1B4M-Gd)(64).

DAB-Am64-(1B4M-Gd)(64) is a newly synthesized macromolecular liver magnetic resonance imaging (MRI) contrast agent with a polypropylenimine diaminobutane (DAB) dendrimer conjugated with a bifunctional diethylenetriaminepentaacetic acid (DTPA) derivative for complexing Gd(III) atoms. The characteristics of DAB-Am64-(1B4M-Gd)(64), which quickly accumulated in the liver, have been reported recently. In the present study, the dynamic micro-MRI with DAB-Am64-(1B4M-Gd)(64) was obtained in the mouse liver metastasis model using colon carcinoma cells to evaluate the ability to visualize the micrometastatic tumors compared with that using Gd-DTPA. The dynamic micro-MRI with DAB-Am64-(1B4M-Gd)(64) was able to homogeneously enhance the normal liver parenchyma and visualize micrometastatic tumors of 0.3-mm diameter in the liver of the mice with better contrast than that with Gd-DTPA. In conclusion, DAB-Am64-(1B4M-Gd)(64) is a new liver MRI contrast agent potentially useful for diagnosis of micrometastasis in the liver.

Animals↗