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Biomedical subjects

T Kubo

Publications and source records attributed to T Kubo.

At least 37 records · Page 2Linked to original sources
PubMed2005

The dependence of the auditory evoked N1m decrement on the bandwidth of preceding notch-filtered noise.

The auditory evoked response is known to be changed by a preceding sound. In this study we investigated by means of magnetoencephalography how a preceding notch-filtered noise (NFN) with different bandwidths influences the human auditory evoked response elicited by the following test stimulus. We prepared white noise (WN) and four NFNs which were derived from WN by suppressing frequency regions around 1 kHz with 1/8-, 1/4-, 1/2- and 1-octave bandwidths. Stimulation for 3 s with this set of noises resulted in differences in responsiveness to a 1-kHz test tone presented 500 ms after the offset of the noises. The N1m response to the 1-kHz test tone stimulus was at a minimum when the preceding NFN had 1/4-octave stop-band frequencies as compared with 1/8-, 1/2- and 1-octave NFN and WN. This N1m decrement is explained by the imbalanced neural activities caused by habituation and lateral inhibition in the auditory system. The results contribute to understanding of the inhibitory system in the human auditory cortex.

Acoustic Stimulation↗
PubMed2005

Prevalence and clinical significance of systolic impairment in hypertrophic cardiomyopathy.

OBJECTIVES: To determine the frequency of systolic impairment (SI) and its impact on the natural history of hypertrophic cardiomyopathy (HCM). METHODS: 1080 patients (mean (SD) age 43 (15) years, 660 men) with HCM were evaluated. Initial assessment included history, examination, 48 hour Holter monitoring, cardiopulmonary exercise testing, and echocardiography; SI was defined as a fractional shortening (FS) < or = 25%. Survival data were collected at clinic visits or by direct communication with patients and their general practitioners. The results of serial echocardiography in 462 patients with normal FS at presentation are also reported. RESULTS: 26 (2.4%) patients (49 (14) years, 18 men) had SI at the initial visit. During follow up (58 (49) months), nine (34.6%) died or underwent cardiac transplantation compared with 108 (10.2%) patients with normal FS (p = 0.01). Five year survival from death (any cause) or transplantation was 90.1% (95% confidence interval (CI) 87.8 to 92.4) in patients with normal systolic function versus 52.4% (95% CI 25.2 to 79.6, p < 0.0001) in patients with SI. In patients who underwent serial echocardiography, 22 (4.8%, aged 41 (15) years) developed SI over 66 (40) months; the annual incidence of SI was 0.87% (95% CI 0.54 to 1.31). On initial evaluation patients who developed SI had a higher frequency of syncope (67 (15.2%) v 10 (45.5%) of those who did not develop SI, p = 0.001), non-sustained ventricular tachycardia (91 (20.6%) v 11 (50%), p = 0.002), and an abnormal blood pressure response on exercise (131 (29.7%) v 15 (68.2%), p = 0.001). Patients with SI had greater wall thinning (p = 0.001), left ventricular cavity enlargement (p < 0.0005), and deterioration in New York Heart Association functional class (p = 0.001) during follow up. Thirteen (59.1%) patients who progressed to SI died or underwent transplantation compared with 38 (8.6%) patients who maintained normal systolic function. CONCLUSIONS: SI is an infrequent complication of HCM but, when present, is associated with a poor prognosis.

Adolescent↗
PubMed2005

Inducing peripheral sympathetic nerve activity by therapeutic electrical stimulation.

PURPOSE: To examine whether the activity of peripheral sympathetic nerves in animals with spinal cord injury can be controlled using therapeutic electrical stimulation. METHODS: The spinal cords of 6 Wistar rats were severed at T12/T13 disk level and were given continuous therapeutic electrical stimulation. Microneurography was used to record sympathetic nerve activity at 24, 48, and 72 hours after severing the spinal cord. RESULTS: Integrated values of muscle sympathetic nerve activity after 72 hours of therapeutic electrical stimulation revealed significantly larger potentials on the stimulated side than the non-stimulated side. Skin sympathetic nerve activity showed no difference between the 2 sides. CONCLUSION: Therapeutic electrical stimulation was found to have a facilitatory effect on the muscle sympathetic nerve activity, whereas regulatory function was activated by the sympathetic nerves.

Animals↗
PubMed2004

The cytoplasmic male-sterile type and normal type mitochondrial genomes of sugar beet share the same complement of genes of known function but differ in the content of expressed ORFs.

The complete nucleotide sequence (501,020 bp) of the mitochondrial genome from cytoplasmic male-sterile (CMS) sugar beet was determined. This enabled us to compare the sequence with that previously published for the mitochondrial genome of normal, male-fertile sugar beet. The comparison revealed that the two genomes have the same complement of genes of known function. The rRNA and tRNA genes encoded in the CMS mitochondrial genome share 100% sequence identity with their respective counterparts in the normal genome. We found a total of 24 single nucleotide substitutions in 11 protein genes encoded by the CMS mitochondrial genome. However, none of these seems to be responsible for male sterility. In addition, several other ORFs were found to be actively transcribed in sugar beet mitochondria. Among these, Norf246 was observed to be present in the normal mitochondrial genome but absent from the CMS genome. However, it seems unlikely that the loss of Norf246 is causally related to the expression of CMS, because previous studies on mitochondrial translation products failed to detect the product of this ORF. Conversely, the CMS genome contains four transcribed ORFs (Satp6presequence, Scox2-2 , Sorf324 and Sorf119) which are missing from the normal genome. These ORFs, which are potential candidates for CMS genes, were shown to be generated by mitochondrial genome rearrangements.

Beta vulgaris↗
PubMed2004

Identification of crotasin, a crotamine-related gene of Crotalus durissus terrificus.

Crotamine is a cationic peptide (4.9 kDa, pI 9.5) of South American rattlesnake, Crotalus durissus terrificus' venom. Its presence varies according to the subspecies or the geographical locality of a given species. At the genomic level, we observed the presence of 1.8 kb gene, Crt-p1, in crotamine-positive specimens and its absence in crotamine-negative ones. In this work, we described a crotamine-related 2.5 kb gene, crotasin (Cts-p2), isolated from crotamine-negative specimens. Reverse transcription coupled to polymerase chain reaction indicates that Cts-p2 is abundantly expressed in several snake tissues, but scarcely expressed in the venom gland. The genome of crotamine-positive specimen contains both Crt-p1 and Cts-p2 genes. The present data suggest that both crotamine and crotasin have evolved by duplication of a common ancestor gene, and the conservation of their three disulfide bonds indicates that they might adopt the same fold as beta-defensin. The physiological function of the crotasin is not yet known.

Amino Acid Sequence↗
PubMed2004

Anomalously hindered E2 strength B(E2;2+(1)-->0+) in 16C.

The electric quadrupole transition from the first 2(+) state to the ground 0(+) state in 16C is studied through measurement of the lifetime by a recoil shadow method applied to inelastically scattered radioactive 16C nuclei. The measured mean lifetime is 77+/-14(stat)+/-19(syst) ps. The central value of mean lifetime corresponds to a B(E2;2+(1)-->0(+)) value of 0.63e(2) fm(4), or 0.26 Weisskopf units. The transition strength is found to be anomalously small compared to the empirically predicted value.

Journal Article↗
PubMed2004

The transcriptional program of synchronous gametogenesis in Chlamydomonas reinhardtii.

Cells of Chlamydomonas reinhardtii undergo gametogenesis to produce sexually competent gametes under nitrogen-starved conditions. By using a synchronized system for gametogenesis of early G1 cells, several previously identified marker genes and 18 novel nitrogen-starved gametogenesis (NSG) genes isolated by macroarray analysis were placed into at least three temporal classes of expression. Early genes are induced transiently in the first 2 h after transfer to nitrogen-free medium. Middle genes are strongly induced between 3 h and 4 h after nitrogen removal, a time corresponding to the acquisition of mating competency, suggesting their involvement in the gamete program. Late genes are induced between 5 h and 8 h after nitrogen removal, a time after the completion of gametic differentiation, suggesting that they are not directly involved in the formation of sexually competent gametes. All of the 18 NSG genes examined are induced in both mating-type plus and minus gametes and about two-thirds of the genes are also expressed in the mitotic cell cycle, especially at S/M phases.

Animals↗
PubMed2004

N1m recovery from decline after exposure to noise with strong spectral contrasts.

Comb-filtered noise (CFN, derived from white noise by suppressing regularly spaced frequency regions) was presented for 3 s followed by two types of test stimuli. One test stimulus (SB) was comprised of spectra centered in the stop-band regions of the CFN and the other test stimulus (PB) of spectra centered in the band pass regions of the CFN. Magnetoencephalographically recorded N1m responses evoked by SB stimuli were decreased relative to the N1m response evoked by PB stimuli. This effect was maximal when the interval between the CFN and test stimuli was short (0.5 s) but was detected at intervals up to 2 s. The results suggest lateral inhibition in the auditory cortex and point to a decay of inhibition lasting on the order of seconds.

Acoustic Stimulation↗
PubMed2004

Vestibular function and vasopressin.

OBJECTIVE: To investigate the relation between the vestibular system and vasopressin (AVP). MATERIAL AND METHODS: We examined the effects of electrical and caloric vestibular stimulation on plasma AVP levels in anesthetized rats. Plasma AVP levels of patients with intractable Ménière's disease who were subjected to endolymphatic drainage and steroid instillation surgery (EDSS) or intratympanic gentamicin (GM) injection were measured before and after these interventions. RESULTS: Electrical vestibular stimulation increased plasma AVP levels in a current intensity-dependent manner. Plasma AVP levels were also increased by caloric stimulation with cold water. Plasma AVP levels decreased rapidly after EDSS, and were maintained at a low level even 6-12 months following EDSS or intratympanic GM injection. CONCLUSIONS: Vestibular activation or inhibition-induced imbalance of intervestibular activities increased plasma AVP levels in rats. Therefore, vestibular disorder would seem to increase plasma AVP and thus worsen endolymphatic hydrops. EDSS rapidly decreased plasma AVP and would seem to reduce hydrops. Inhibition of vertigo spells by EDSS or intratympanic GM injection would reduce a possible stress response, resulting in a decrease in plasma AVP levels a long time after the treatments. This resultant decrease in AVP would beneficially inhibit the formation and/or maintenance of hydrops and thus prevent vertigo spells.

Animals↗
PubMed2004

Expression level of valosin-containing protein (VCP) as a prognostic marker for gingival squamous cell carcinoma.

BACKGROUND: Valosin-containing protein (VCP) is associated with anti-apoptotic function and metastasis via activation of the nuclear factor-kappaB signaling pathway. In the present study, association of VCP expression with prognosis of gingival squamous cell carcinoma (GSCC) was examined. PATIENTS AND METHODS: VCP expression in 74 patients with GSCC (34 males and 40 females) with ages ranging from 42 to 85 (median 66) years was evaluated by immunohistochemistry, in which staining intensity in tumor cells was categorized as either weaker (level 1) or equal to/stronger (level 2) than that in the endothelial cells. RESULTS: Twenty-four (32.4%) cases showed level 1 and 50 (67.6%) level 2 VCP expression. Patients with level 1 GSCC showed a significantly better 5-year survival rate than those with level 2 GSCC (5-year overall survival: 100% versus 84.9%, P < 0.05). Multivariate analysis revealed VCP expression level, lymph node metastasis and pT(TNM) to be independent factors for overall survival. Patients with GSCC at stages I and II showed favorable prognosis regardless of VCP expression status, whereas at stages III and IV, patients with level 1 VCP expression showed better survival rates than those with level 2 expression. CONCLUSION: Prognostic significance of VCP expression level in GSCC was demonstrated.

Adenosine Triphosphatases↗
PubMed2004

Lateral inhibition and habituation of the human auditory cortex.

The goal of this study was to compare the lateral inhibition and the habituation in the human auditory cortex, two important physiological effects during auditory processing that can be reliably measured by means of magnetoencephalography when recording auditory evoked fields. Applying 40-Hz amplitude-modulated stimuli allowed us to record simultaneously the slow transient evoked and the steady-state fields and thus to characterize the lateral inhibition and the habituation effect in primary and non-primary auditory cortical structures. The main finding of the study is that the lateral inhibition effect of non-primary auditory areas as measured on the major component of the slow transient auditory evoked field (N1) is significantly stronger than the corresponding habituation effect. By contrast, this effect was not observed for the 40-Hz steady-state fields, characterizing the activation of the primary auditory cortex in humans. The results might be interpreted as (i) evidence that the inhibition mediated by lateral connections is stronger than the habituation of excitatory neurons in the non-primary auditory cortex and (ii) the processing hierarchy in the human auditory cortex is demonstrated by the different behaviour of lateral inhibition and habituation in primary and non-primary auditory cortical structures.

Acoustic Stimulation↗
PubMed2004

Rapid healing of intractable diabetic foot ulcers with exposed bones following a novel therapy of exposing bone marrow cells and then grafting epidermal sheets.

BACKGROUND: Diabetic foot ulcers with exposed bones commonly result in amputation. OBJECTIVES: To determine whether exposure of bone marrow cells and subsequent grafting of epidermal sheets accelerates healing and reduces the need for amputation. METHODS: Thirty-eight patients with chronic wounds caused by diabetes mellitus were enrolled in this study. Epidermal sheets obtained from suction blisters of each patient were grafted on to diabetic foot ulcers without exposed bones (n = 10) and were compared with the standard treatment of local wound care, debridement with a scalpel when indicated, bed rest and parenteral antibiotics (n = 8). In another group of patients, diabetic wounds with exposed bones were treated either with the standard procedure (n = 9) or with a newly developed experimental procedure (n = 11). In that new procedure, the affected bone was initially exposed by debridement with a scalpel, followed by partial excision with a bone scraper until fresh bleeding was observed from the exposed bone. The lesions were then immediately covered with an occlusive dressing, and finally the wound was covered with an epidermal graft of skin harvested from suction blisters. Patients in each group were matched with their counterparts by age, sex, wound size, wound infection and wound duration, to compare the time needed for total skin repair and rates of amputation. RESULTS: Epidermal grafting significantly accelerated the healing of diabetic foot ulcers (P = 0.042) without exposed bones, with site-specific differentiation. The newly developed combination therapy resulted in the healing of all diabetic ulcers with exposed bones without the occurrence of osteomyelitis or the necessity for amputation (P < 0.0001). CONCLUSIONS: Our study indicates that early aggressive debridement of diabetic foot ulcers with exposed bones down to a bleeding vascularized base and then grafting epidermal sheets significantly improves healing and reduces the rate of amputation.

Adult↗
PubMed2004

Sympathetic skin response in patients with spinal cord injury.

PURPOSE: To assess the effectiveness of sympathetic skin response in evaluating peripheral sympathetic nerve activity of patients with spinal cord injury, and to report on the basic properties of sympathetic skin response. METHODS: Sympathetic skin response evoked by electrical stimulation was recorded from the palms and soles of healthy volunteers and patients with spinal cord injury. RESULTS: Sympathetic skin response was recorded in 17 healthy volunteers and 14 patients with spinal cord injury. Of the 4 waveforms, the shortest latency was obtained from the palm; the sympathetic skin response was 1.2 to 1.4 ms at all stimulated sites, 1.9 to 2.0 ms at the sole, with a difference of about 0.6 ms between the palm and the sole. None of the patients with spinal cord injury responded at either the upper or lower limbs. In patients with a thoracic cord injury, some responded at the upper limbs but none at the lower limbs; some responded at neither upper nor the lower limbs; and some responded at both upper and lower limbs. The conducting pathway of sympathetic skin response in the spinal cord for the upper limbs descends to the upper thoracic cord (T4-6), and the conducting pathway for the lower limbs departs from the spinal cord at the lower thoracic cord (T9-10). CONCLUSION: It appears that sympathetic skin response should be used for the evaluation and morbid investigation of the functional abnormalities of the sympathetic nervous system in patients with spinal cord lesions such as spinal cord injuries, cervical spondylosis, and spinal canal stenosis.

Adolescent↗
PubMed2004

Diagnostic utility of waveform analysis of compound muscle action potentials for carpal tunnel syndrome.

PURPOSE: To determine the diagnostic utility of waveform analysis of compound muscle action potentials (CMAP) for carpal tunnel syndrome (CTS). METHODS: A total of 131 hands in 71 patients diagnosed with CTS (grouped according to severity) and 80 hands in 44 normal subjects were evaluated using nerve conduction test through the carpal tunnel combined with waveform analysis of CMAP. RESULTS: Compared to normal subjects, the sensory nerve conduction velocity and mean frequency of the CMAP waveform were significantly reduced in patients with CTS. Compared with distal motor latency and sensory nerve conduction velocity, the mean frequency of the CMAP decreased significantly with increasing clinical severity. CONCLUSION: This study suggests that waveform analysis of CMAP is of diagnostic value in CTS, and is also of value in objective evaluation of postoperative recovery of carpal median nerve dysfunction.

Action Potentials↗
PubMed2003

Action of FGMgCO3Ap-collagen composite in promoting bone formation.

To improve the biological properties of materials as bone substitutes, functionally graded CO3 apatite crystals containing magnesium, FGMgCO3Ap, were synthesized to be mixed with atelocollagen and made into a composite pellet. A radio-labeled cell adhesion experiment showed that the degree of adherence of mouse MC3T3E1 osteoblast-like cells to the FGMgCO3Ap-collagen composite was better than to CO3Ap-collagen and much better than to the Ti plate. When the composites were implanted beneath the periosteum cranii of rats, the FGMgCO3Ap-collagen composite was metabolized faster than the CO3Ap-collagen composite and better formation of new bone and osteoblast arrangement at the interface between the composite and the periosteum cranii was observed. When the composites were implanted into the femur of rabbits, clear bone formation with a higher degree of bone density was observed for the FGMgCO3Ap-collagen composite. These results suggest that the Mg2+ ions taken into the apatite crystals may contribute to the acceleration of osteoblast adhesion to apatites and promote bone formation, cross-talking with osteoblasts at the molecular level.

3-Hydroxysteroid Dehydrogenases↗
PubMed2003

The mitochondrial acetoacetyl-CoA thiolase (T2) deficiency in Japanese patients: urinary organic acid and blood acylcarnitine profiles under stable conditions have subtle abnormalities in T2-deficient patients with some residual T2 activity.

Mitochondrial acetoacetyl-CoA thiolase (T2) deficiency is an inborn error of metabolism affecting isoleucine and ketone bodies in the catabolic process. Mutation analysis and expression analysis of mutant cDNAs have facilitated the division of T2-deficient patients into two groups: those with null mutations in either allele (group 1) and those with mutation(s) retaining some residual T2 activity in at least one of two mutant alleles (group II). Among 5 Japanese T2-deficient patients, GK01 belonged to group I and the other patients (GK19, GK19B, GK30 and GK31) to group II. As we have suggested previously, the severity of ketoacidotic episodes in the group II patients was similar to that in the group I patient. However, the urinary organic acid and blood spot acylcarnitine profiles under stable conditions differed between the two groups. The group I patient had typical profiles for the T2 deficiency. In contrast, in all four patients in group II, tiglylglycine was not or was only faintly detected and the 2-methyl-3-hydroxybutyrate levels were less than the cutoff value. Their tiglylcarnitine levels were within the normal range and 2-methyl-3-hydroxy-, butyrylcarnitine was detected just around the cutoff value in our newborn screening pilot test. Hence, these analyses under stable conditions are not reliable for diagnosing the T2 deficiency in the group II patients. The T2 deficiency (group II) can be misdiagnosed as normal if these analyses are performed under nonepisodic conditions and possibly during the newborn screening for inborn errors of metabolism.

Acetoacetates↗
PubMed2003

Identification of a tachykinin-related neuropeptide from the honeybee brain using direct MALDI-TOF MS and its gene expression in worker, queen and drone heads.

Using a combination of MALDI-TOF and on-line capillary HPLC/Q-Tof mass spectroscopy, we identified and determined the amino acid sequence of a novel neuropeptide in the brain of the honeybee Apis mellifera L., termed AmTRP peptide (Apis mellifera tachykinin-related peptide), related to insect tachykinin. A cDNA for a prepro-protein (prepro-AmTRP) of AmTRP was isolated and determined to encode seven AmTRPs 1-7. Northern blot analysis indicated that the prepro-AmTRP gene is expressed differentially in the nurse bee, forager, queen and drone heads. Strong expression was detected in the queen and forager heads, while weak and almost no significant expression was detected in the nurse and drone heads, respectively. These results suggest that AmTRP peptide functions as a neuromodulator and/or hormone, associated with sex-specific or age/division of labour-selective behaviour and/or physiology of the honeybees.

Amino Acid Sequence↗