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Biomedical subjects

Takeshi Hatta

Publications and source records attributed to Takeshi Hatta.

15 recordsLinked to original sources
PubMed2006

RNA interference of cytosolic leucine aminopeptidase reduces fecundity in the hard tick, Haemaphysalis longicornis.

Ticks are effective vectors of pathogens because of their blood feeding and high fecundity. This high fecundity is related to the size of the blood meal. Therefore, knowledge of how blood proteins are degraded and converted to proteins, including yolk protein, is important for the development of ways to inhibit the utilization of blood proteins by ticks. RNA interference (RNAi) is becoming a powerful post-transcriptional gene silencing technique that provides insight into gene function. We constructed a double-stranded RNA (dsRNA) based on a previously cloned Haemaphysalis longicornis leucine aminopeptidase (HlLAP) gene to reevaluate the biological role in tick blood digestion. Gene specific transcriptional, translational, and functional disruptions were achieved by the introduction of dsRNA into the ticks. Significantly delayed onset of egg-laying and reduced egg oviposition resulted from the RNAi for the HlLAP gene. These results suggest that HlLAP actually works as a blood digestive enzyme and affects tick fecundity via unknown mechanisms. The reduction of egg oviposition may be caused by a decrease in nutrients, especially free amino acids generated by HlLAP, from the blood meal. This is the first report of an impact on tick reproduction caused by gene silencing of a blood digestion-related molecule.

Animals↗
PubMed2006

Haemaphysalis longicornis: molecular characterization of a homologue of the macrophage migration inhibitory factor from the partially fed ticks.

The macrophage migration inhibitory factor (MIF) has been identified from some vertebrates and invertebrates. MIF is related to inflammation, tumor growth, and angiogenesis in vertebrates. Here, we report the molecular characterization of a homologue of MIF from partially fed Haemaphysalis longicornis. The sequence analysis of the H. longicornis MIF (HlMIF) indicated that its deduced amino acid sequence has an identity of 77% with the MIF of the tick Amblyomma americanum. Western blot analysis using the anti-His-HlMIF antibody showed that HlMIF was up-regulated during blood feeding. Immunohistochemistry showed that the endogenous HlMIF in partially fed ticks was localized to the midgut and epidermal cells. Moreover, the functional assay revealed that the GST-HlMIF inhibited the migration of human monocytes. In conclusion, we consider that HlMIF may facilitate blood feeding by inhibiting host macrophage migration to the feeding lesion or may participate in the proliferation and differentiation of cells in the tick body.

Amino Acid Sequence↗
PubMed2006

Identification and characterisation of a leucine aminopeptidase from the hard tick Haemaphysalis longicornis.

Aminopeptidases responsible for blood digestion have yet to be identified in haematophagous ticks. We report here the cloning and molecular characterisation of a cDNA encoding leucine aminopeptidase, a member of the M17 cytosolic aminopeptidase family, from the hard tick Haemaphysalis longicornis (HlLAP). Endogenous HlLAP was detected in the soluble fraction of adult tick extracts by immunoblotting. Immunohistochemical studies demonstrated that endogenous HlLAP expression mainly took place in the cytosol of midgut epithelial cells. Furthermore, expression of HlLAP was induced by a blood-feeding process. A functional recombinant HlLAP expressed in Escherichia coli efficiently hydrolyses synthetic substrates for aminopeptidase, a leucyl (with the Km value 0.19 +/- 0.011 mM and Vmax value 157.2 +/- 3.17 nmol/min/mgprotein) and a methionyl substrate (with the Km value 0.12+/-0.0052 mM and Vmax value 171.9 +/- 2.31 nmol/min/mgprotein). Enzyme activity was found to be optimum at pH 8 and 35 degrees C. The recombinant HlLAP enzyme activity was strongly dependent on metal divalent cations, Mn2+, and was inhibited by bestatin. These results indicate that HlLAP play an important role for host's blood digestion process.

Amino Acid Sequence↗
PubMed2006

Identification of a follistatin-related protein from the tick Haemaphysalis longicornis and its effect on tick oviposition.

The identification of ovary-associated molecules will lead to a better understanding of the physiology of tick reproduction and vector-pathogen interactions. A gene encoding a follistatin-related protein (FRP) was obtained by random sequencing from the ovary cDNA library of the tick Haemaphysalis longicornis. The full-length cDNA is 1157 bp, including an intact ORF encoding an expected protein with 289 amino acids. Three distinct domains were present in the deduced amino acids, namely, the follistatin-like domain, KAZAL, and two calcium-binding motifs, EFh. The sequence shows homology with the follistatin-related protein (FRP), which was thought to play some roles in the negative regulation of cellular growth. RT-PCR showed that the gene was expressed throughout the developing stages and mainly in the ovary as well as in fat body, hemocytes, salivary glands, and midgut. This gene was expressed in GST-fused recombinant protein with an expected size. The mouse antiserum against the recombinant protein recognized a 56-kDa native protein in both tick ovary and hemolymph. The recombinant proteins were found to have binding activity for both activin A and bone morphogenetic protein-2 (BMP-2). Silencing of FRP by RNAi showed a decrease in tick oviposition, which is consistent with the effect of a recombinant protein vaccine on the adult tick. These results showed that the tick FRP might be involved in tick oviposition. This is the first report of a member of follistatin family proteins in Chelicerata, which include ticks, spiders, and scorpions.

Activins↗
PubMed2005

Effects of learning experience on bihemispheric processing.

The purpose of this study was to examine the effect of learning experience on benefits of bihemispheric processing. First, right-handed students were given the paired-associated learning task that required them to memorize the pairs of a familiar-font letter with an unfamiliar-font letter. After this task, both the letters were presented in the unilateral (UVF) and bilateral visual-fields (BVF) (Test 1). They were asked to decide if both the letters were the match. Second, the learning task was given to them, followed by the same letter-matching task (Test 2). The results showed that a UVF-advantage in Test 1 shifted toward a BVF-advantage in Test 2. These findings suggested that, as the amount of learning increased, the benefits of bihemispheric processing would be enhanced.

Adult↗
PubMed2005

Lower-limb asymmetries in early and late middle age.

The present study examined the relationship between upper- and lower-limb laterality and the difference in kinaesthetic function between lower limbs. A total of 360 early and late middle-aged people from rural areas in Japan participated in the study. The first purpose was to describe upper- and lower-limb lateral preferences. Approximately 80% of the population showed uncrossed lateral preference between hand and foot (i.e., right-handed and right-footed or left-handed and left-footed). Furthermore, the proportions of uncrossed type population were similar among the four age groups (30s-40s, 50s, 60s, and 70s). The second purpose was to examine the lateral differences in leg muscle strength in order to seek possible reasons for a leftward bias in the occurrence of hip fractures. Leg muscle strength was measured by a strengthergometer. The muscle strength of the left leg (non-preferred) was stronger than that of the right (preferred) leg in the 50s age group, whereas there was no significant difference between the two lower limbs in the other age groups (30s-40s, 60s, 70s). This finding suggests that greater fatigue on the left leg bone system might induce the high occurrence of left hip fractures.

Adult↗
PubMed2004

Infrainguinal bypass surgery for chronic arterial occlusive disease associated with essential thrombocythemia: report of a case.

A 63-year-old man was referred to our hospital with a 3-year history of intermittent claudication, and his angiogram showed a total occlusion of the bilateral infrainguinal arteries. In addition, based on a platelet count of 172 x 10(4)/mm(3) as well as the characteristic bone marrow findings, he was diagnosed to have essential thrombocythemia. After the platelet count and aggregation response improved on administration of ranimustine and antiplatelet agents, infrainguinal bypass surgery was performed using the saphenous vein and prosthetic grafts. The bilateral grafts had been patent for 10 months postoperatively, but his discontinuance of medication caused an acute occlusion of the prosthetic graft. The graft was salvaged with a prompt thrombectomy and, now under strict medication control, he is leading an active life.

Angiography, Digital Subtraction↗
PubMed2004

Large perigraft seroma after aortoiliac bypass with an expanded polytetrafluoroethylene graft: report of a case.

A 63-year-old man who had undergone aortoiliac bypass with an expanded polytetrafluoroethylene (PTFE) graft was referred to our hospital for investigation and treatment of a possible pseudoaneurysm of the abdominal aorta. A tender, pulsatile, and bulging mass, about the size of an adult fist, was palpated around the navel. Enhanced computed tomography (CT) showed a large low-density area around the abdominal aorta and PTFE graft, and aortography showed a patent graft with no anastomotic leakage. Operative inspection revealed that the pulsatile mass was a large perigraft seroma, and we replaced the PTFE graft with a new woven Dacron graft. The patient has been well with no sign of recurrence for 1 year, although close long-term follow-up is mandatory.

Aorta, Abdominal↗
PubMed2004

Differential processing of implicature in individuals with left and right brain damage.

To evaluate the processing ability of implicature , especially indirect request and indirect refusal, the Four Scenes Test was administered to 20 left hemisphere damaged (LHD) subjects, 20 right hemisphere damaged (RHD) subjects and 15 normal control subjects. The results showed first, that the performances of the brain-damaged subjects was inferior to that of the control subjects in processing implicature; second, that indirect request understanding was easier than indirect refusal understanding in the brain-damaged subjects, and the third that indirect refusal understanding in of the left hemisphere damaged subjects was inferior to that of the right hemisphere damaged subjects. There was no group difference in indirect request understanding though the ability of brain-damaged subjects was poorer than that of the normal controls. These findings suggest that LHD and RHD subjects were not the same in implicature processing and their responses depended on the implicature's modularity (refusal and request).

Aged↗
PubMed2004

Relation between the prefrontal cortex and cerebro-cerebellar functions: evidence from the results of stabilometrical indexes.

The relation between prefrontal cortex and cerebro-cerebellar functions of 50 normal healthy elderly people was examined. The function of the prefrontal cortex was measured by means of a letter fluency test and the Digit Cancellation Test (D-CAT, a test for the assessment of attention). Two indexes of postural tremor measured by the stabilometer were employed for the indication of cerebello-thalamo-cortical circuit functions. The results of groups consisting of participants showing higher or lower scores than the mean of the norm on the stabilometer index measurements were compared with their D-CAT and letter fluency test performances. The results showed that 2 indexes of cerebello-thalamo-cortical circuit functions related to the attention function while the relation to the language function was rather weak. The results of the behavioral measures demonstrated a mutual relation between prefrontal cortex and cerebello-thalamo-cortical circuit functions and strongly suggest the notion that the human brain functions as a system, which includes neocortex, subcortex, and cerebellum.

Aged↗
PubMed2004

Spatial structure of quantitative representation of numbers: evidence from the SNARC effect.

Dehaene, Bossini, and Giraux (1993) revealed that subjects responded to large numbers faster with the choice on the right than with the choice on the left, whereas the reverse held true for small numbers (SNARC effect). According to Dehaene et al. (1993), the SNARC effect depends on the quantitative representation of number, such as a left-to-right-oriented analog number line. The main goal of the present study was twofold: first, to investigate whether the vertical SNARC effect could be observed, and, second, to verify whether Dehaene et al.'s (1993) explanation of the SNARC effect is correct. Experiments 2A and 2B showed the vertical SNARC effect in a parity judgment task. Subjects responded to large numbers faster with the top choice than with the bottom choice, whereas the reverse held true for small numbers. However, Experiment 3 failed to show the SNARC effect in a number magnitude judgment task, suggesting that the quantitative representation could be dissociated from the spatial code that produces the SNARC effect.

Adult↗
PubMed2003

Semantic processing of Arabic, Kanji, and Kana numbers: evidence from interference in physical and numerical size judgments.

Two experiments were conducted with the following objectives (1) to replicate the finding of similar semantic representation of Arabic and written-word (Kanji and Kana) numbers with a direct numerical task, (2) to investigate the automatic semantic processing of Arabic and written-word numbers, and (3) to verify whether the assumption of a common semantic representation is valid in an indirect numerical task. Subjects were asked to judge which of two numbers (e.g, 6-8) was larger either in its numerical size (Experiment 1) or in its physical size (Experiment 2) using the three notations. Effects of two factors were analyzed: the congruity between numerical and physical size and the numerical distance. The effects of these factors were very similar across the three notations in Experiment 1, but were drastically different in Experiment 2. The results of Experiment 2 demonstrated the nonsemantic processing of Kana numbers, and suggest that there may be separate semantic representations for Arabic and Kanji numbers.

Adult↗
PubMed2002

Effects of type of cognitive demand on bilateral advantage in interhemispheric processing.

The relationship between cognitive task demand and effect of bilateral advantage (BLA) was examined. In Experiment 1, the task demand based upon visual stimulus complexity was manipulated. One-digit and two-digit numbers were presented in the left, right or both visual fields tachistoscopically and subjects were requested to identify the numbers. The results showed no BLA, although a right visual field advantage was demonstrated. In Experiment 2, cognitive demand in terms of memory was manipulated. Subjects were asked to recall one-digit numbers that were presented successively once, three and five times in the left, right or the both visual fields. The results did not show any sign of BLA in the recall of numbers. In Experiment 3, a greater memory load task was given than that in Experiment 2, where two-digit numbers were presented successively (once, three and five times). Subjects were asked to recall the numbers. The results showed a significant BLA in the recall of numbers, i.e., the correct numbers in the correct temporal positions. These results strongly suggest that a benefit of redundant bilateral visual fields presentation is shown only in a highly cognitively demanding task, especially when it involves phonological memory loads.

Adult↗
PubMed2002

Surgical treatment for acute ischemia caused by bilateral popliteal artery entrapment syndrome in an elderly patient: report of a case.

We report the unusual case of a 73-year-old man who underwent surgery for bilateral popliteal artery entrapment syndrome (PAES). A medial approach was used to operate on the left leg, and the vein bypass was made from the superficial femoral artery to the crural artery through a subfascial route. A posterior approach was used to operate on the right leg and it was found that the mid-popliteal artery passed medial to and beneath the medial head of the gastrocnemius muscle and was severely compressed by an accessory slip of muscle. The vein bypass from the above-knee to below-knee popliteal artery was established through the original route after resection of the accessory slip of muscle. A postoperative arteriogram showed good bypass flow to the bilateral crural arteries. To our knowledge, this case represents the oldest patient with this disorder to be treated by surgery.

Aged↗