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Biomedical subjects

M Komatsu

Publications and source records attributed to M Komatsu.

At least 19 recordsLinked to original sources
PubMed2006

Quantitative trait loci mapping for fatty acid composition traits in perirenal and back fat using a Japanese wild boar x Large White intercross.

Here, we analysed quantitative trait loci (QTL) for fatty acid composition, one of the factors affecting fat quality, in a Japanese wild boar x Large White cross. We found 25 significant effects for 17 traits at 13 positions at the 5% genome-wise level, of which 16 effects for 12 traits at 10 positions were significant at the 1% level. QTL for saturated fatty acids (SFA) in back fat were mapped to swine (Sus scrofa) chromosomes (SSC) 1p, 9 and 15. QTL for unsaturated fatty acids in back fat were mapped to SSC1p, 1q, 4, 5, 9, 15 and 17. Using a regression model that fits back fat thickness as a covariate, two of the QTL for linoleic acid content on SSC4 and SSC17 were not significant, but one QTL for total SFA composition was detected on SSC5 with correction for back fat thickness. Wild boar alleles at six of seven QTL tended to increase SFAs and to decrease unsaturated fatty acids. QTL for fatty acid composition in perirenal fat were mapped on SSC2, 3, 4, 5, 6, 14, 16 and X. QTL for melting point (in back fat samples) were mapped on SSC1, 2 and 15. Wild boar alleles in QTL on SSC1 and SSC15 were associated with elevated melting points whereas those on SSC2 were associated with lower melting point measurements.

Adipose Tissue↗
PubMed2005

Electrochemical characterization of cast Ti-Hf binary alloys.

This study characterized the electrochemical behavior of Ti-Hf binary alloys in a simulated oral environment. Ti-Hf alloys (10, 20, 25, 30, 35 and 40 mass% Hf) were prepared by arc-melting titanium sponge and hafnium sponge. Specimens of each alloy (n = 4) were prepared using a dental titanium casting system with a MgO-based investment. Specimens were inspected with X-ray radiography to ensure minimal internal porosity. Castings (n = 4) made from pure titanium and commercially pure titanium were used as controls. The ground flat surface (10 mm x 10 mm) on each specimen where approximately 30 microm was removed was used for the characterization. Sixteen-hour open-circuit potential (OCP) measurement, linear polarization and potentiodynamic cathodic polarization were performed sequentially in aerated (air + 10% CO2) MTZ synthetic saliva at 37 degrees C. Potentiodynamic anodic polarization was conducted in the same medium but deaerated (N2 + 10% CO2) 2 h before and during testing. Polarization resistance (R(P)) and Tafel slopes were determined, as were corrosion current density (I(CORR)) and passive current density (I(PASS)). Results were subjected to nonparametric statistical analysis (alpha = 0.05). The OCP stabilized (mean values -229 mV to -470 mV vs. SCE) for all specimens after the 16-h immersion. Similar passivation was observed for all the metals on their anodic polarization diagrams. The Kruskal-Wallis test showed significant differences in OCP among the test groups (p = 0.006). No significant differences were found in R(P), I(CORR) or I(PASS) among all the metals (p>0.3). Results indicate that the electrochemical behavior of the Ti-Hf alloys examined resembles that of pure titanium.

Alloys↗
PubMed2005

The first record of Dirofilaria immitis infection in a Humboldt penguin, Spheniscus humboldti.

Dirofilaria immitis infection is an important parastic disease in many mammals, especially canids, but has not been reported in bird hosts. Filarial worms were isolated from the lumen of the right atrium of the heart and the connective tissue of the lung of a captive female Humboldt penguin, Spheniscus humboldti, that died at a zoo in Japan. One of these worms was observed morphologically and identified as D. immitis by features such as 4 pairs of cephalic papillae, 1 pair of cervical papillae, esophagus divided into 2 regions, 4 pairs of pre-anal papillae, 5 pairs of post-anal papillae, and unequal spicules. In addition, the partial DNA sequence (234 bp) of mitochondrial CO / gene of the filarial worm was identical to that of D. immitis. This is the first report of D. immitis infection in a bird.

Animals↗
PubMed2005

Quantitative trait loci mapping for meat quality and muscle fiber traits in a Japanese wild boar x Large White intercross.

Three generations of a swine family produced by crossing a Japanese wild boar and three Large White female pigs were used to map QTL for various production traits. Here we report the results of QTL analyses for skeletal muscle fiber composition and meat quality traits based on phenotypic data of 353 F(2) animals and genotypic data of 225 markers covering almost the entire pig genome for all of the F(2) animals as well as their F(1) parents and F(0) grandparents. The results of a genome scan using least squares regression interval mapping provided evidence that QTL (<1% genome-wise error rate) affected the proportion of the number of type IIA muscle fibers on SSC2, the number of type IIB on SSC14, the relative area (RA) of type I on SSCX, the RA of type IIA on SSC6, the RA of type IIB on SSC6 and SSC14, the Minolta a* values of loin on SSC4 and SSC6, the Minolta b* value of loin on SSC15, and the hematin content of the LM on SSC6. Quantitative trait loci (<5% genome-wise error rate) were found for the number of type I on SSC1, SSC14, and SSCX, for the number of type IIA on SSC14, for the number of type IIB on SSC2, for the RA of type IIA on SSC2, for the Minolta b* value of loin on SSC3, for the pH of loin on SSC15, and for the i.m. fat content on SSC15. Twenty-four QTL were detected for 11 traits at the 5% genome-wise level. Some traits were associated with each other, so the 24 QTL were located on 11 genomic regions. In five QTL located on SSC2, SSC6, and SSC14, each wild boar allele had the effect of increasing types I and IIA muscle fibers and decreasing type IIB muscle fibers. These effects are expected to improve meat quality.

Animals↗
PubMed2004

A new computer-assisted method for measuring the tibio-femoral angle in patients with osteoarthritis of the knee.

OBJECTIVE: The purpose of this study was to evaluate the inter- and intraobserver variability in measuring the tibio-femoral angle using our new computer-assisted method, and to compare it with a conventional manual method. METHODS: Radiography of all patients of osteoarthritis of the knee in outpatient were performed with standing on both legs, and with conventional antero-posterior weight bearing view of the knee fully extended. Three examiners measured the tibio-femoral angle with the computerized method in 52 subjects with osteoarthritis (73 knees). The tibio-femoral angle was measured using a computer-assisted method in which the observer must visually determine and select eight points on the margins of the femur and tibia on a radiographic image displayed on a computer monitor. The inter- and intraobserver Intra-class correlation (ICC) was analyzed. RESULTS: The interobserver mean correlation of computer-assisted method was 0.970 with a mean difference of 0.38 degrees (S.D. 1.125 degrees). The intraobserver mean ICC of computer-assisted method was 0.973, with a mean difference of 0.16 degrees (S.D. 1.12 degrees). An analysis of the difference between conventional methods and our new system showed a mean ICC of 0.922, with an intersystem mean difference of 0.295 degrees (S.D. 1.82 degrees). CONCLUSION: Our computer-assisted method of measuring the tibio-femoral angle was simple, easy, and quick, and should be considered as an alternate method for measurement.

Adult↗
PubMed2004

Nutritional secondary hyperparathyroidism and osteodystrophia fibrosa in a Hodgson's hawk-eagle (Spizaetus nipalensis).

A Hodgson's hawk-eagle (Spizaetus nipalensis) reared by a falconer showed severe weakness with multiple fractures of bone. It had a history of being fed an all-meat diet. Serological examination revealed a hypocalcaemia (72.0 microg/ml), and hypophosphataemia (29.0 microg/ml). Gross and microscopic examinations demonstrated severe osteodystrophia fibrosa (fibrous osteodystrophy) characterized by osteoclastic bone resorption and intertrabecular fibrosis with unmineralized trabecular bone containing a large amount of unmineralized osteoid. There was also hypertrophy and hyperplasia of the parathyroid glands, which is consistent with nutritional secondary hyperparathyroidism.

Animal Feed↗
PubMed2003

Gene expression of leukemia inhibitory factor (LIF) and macrophage colony stimulating factor (M-CSF) in bovine endometrium during early pregnancy.

Leukemia inhibitory factor (LIF) and macrophage colony stimulating factor (M-CSF), members of the group of hemopoietic cytokines, play a primary role in the control of embryo development and implantation and in the growth of the placenta in humans and mice. Gene expressions of LIF and M-CSF were investigated using quantitative RT-PCR in bovine endometrial tissues during early and mid-pregnancy (Days 16-17, 20-21, 30-36, 48-49 and 74-140) and during the estrous cycle (Days 13-14). Leukemia inhibitory factor and M-CSF genes were expressed in all samples examined. Significant differences were found between the gene expression patterns of LIF and M-CSF. Leukemia inhibitory factor expression level at Days 48-49 was the highest in caruncular endometrium, however, the large variability negated any significant differences. Leukemia inhibitory factor expression levels in intercaruncular endometrium at Days 48-49 and 74-140 of pregnancy were greater than at Days 13-14 of the estrous cycle and at other days of pregnancy. No significant change was recognized in M-CSF expression levels in caruncular endometrium. Macrophage colony stimulating factor expression level in intercaruncular endometrium at Days 74-140 was greater than those of the other samples. These results suggest that LIF and M-CSF are produced in the endometrium and may play different roles in early and mid-pregnancy.

Animals↗
PubMed2003

High frequency of antibiotic-associated diarrhea due to toxin A-negative, toxin B-positive Clostridium difficile in a hospital in Japan and risk factors for infection.

Patients hospitalized in a hospital with a high incidence of antibiotic-associated diarrhea due to toxin A-negative, toxin B-positive (A-/B+) Clostridium difficile were retrospectively investigated to determine the clinical manifestations and risk factors for infection. Of 77 Clostridium difficile isolates obtained from 77 patients during the 1-year investigation period, 30 were A-/B+ and 47 were toxin A-positive, toxin B-positive (A+/B+). By pulsed-field gel electrophoresis analysis, 23 of the 30 A-/B+ strains were outbreak-related, suggesting nosocomial spread of a single type of bacterium, which mainly affected patients in the wards of respiratory medicine, hematology and neurology. Using regression analysis, three factors were found to be associated with infection by A-/B+ isolates: (i) exposure to antineoplastic agents ( P=0.01, odds ratio [OR]=5.1), (ii) the use of nasal feeding tubes ( P=0.008, OR=5.2), and (iii) assignment to a certain internal medicine ward ( P=0.05, OR=3.0). Between patients with Clostridium difficile-associated diarrhea caused by A-/B+ strains and those with A+/B+ strains, no statistically significant difference was found in body temperature, serum concentration of C-reactive protein, leukocyte count in whole blood, frequency of diarrhea, or type of underlying disease. These results indicate that A-/B+ strains of Clostridium difficile can cause intestinal infection in humans and they spread nosocomially in the same manner as A+/B+ strains.

Adolescent↗
PubMed2003

Holmium:YAG laser-induced liquid jet dissector: a novel prototype device for dissecting organs without impairing vessels.

BACKGROUND AND OBJECTIVE: Neurosurgery has long required a method for dissecting brain tissue without damaging principal vessels and adjacent tissue, so as to prevent neurological complications after operation. In this study we fabricated such a prototype device and used it in an attempt to resect an animal liver, which, like the brain, contains many vessels. MATERIALS AND METHODS: The prototype device consisted of a jet nozzle and a suction tube. Pulsed liquid jets at 3 Hz were ejected from the nozzle by a pulsed holmium:YAG (Ho:YAG) laser at an irradiation energy of 230 mJ/pulse. The profile of the liquid jet was observed with a high-speed camera. With this device, liver dissections of anesthetized rabbits were attempted while measuring the local temperature of the target. A histological study of the incised parts was also performed. RESULTS: The liquid jet was emitted straight from the nozzle at an initial velocity of 38 m/sec. The liver parenchyma was cut with the device while preserving the tiny vessels and keeping the operative field clear. The local temperature rose to no more than 314 K (below the heat damage threshold of brain tissue). In the histological findings, there were no signs of hepatic degeneration or necrosis around the dissected margin. CONCLUSIONS: The Ho:YAG laser-induced liquid jet dissector can be applied to neurosurgical operations after incorporating some minor improvements.

Animals↗
PubMed2002

A novel method of drug delivery for fibrinolysis with Ho:YAG laser-induced liquid jet.

Two of the problems inherent in the treatment of cerebral emboli are the narrow therapeutic time window and the severe side effects of fibrinolytic drugs. Thus, it is necessary to develop a new method of removing a cerebral thrombus more rapidly and with smaller quantities of fibrinolytics. The behaviour of a bubble formed by holmium (Ho):YAG laser irradiation in a capillary tube filled with pure water was observed at various stand-off distances (L; distance between the end of optical fibre and the capillary exit). Subsequently, a liquid-jet generator was created by insertion of an optical fibre (core diameter: 0.6 mm) into a catheter (6 Fr) filled with pure water, and a pulsed Ho:YAG laser (pulse duration time=350 micros, laser energy=230 mJ/pulse) was used to irradiate the optical fibre. The maximum penetration depth, into a gelatin artificial thrombus, of a liquid jet generated with this device was measured for various stand-off distances. Additionally, the phenomenon and the pressure around the catheter exit were captured via shadowgraph and PVDF needle hydrophone, respectively. The laser-induced bubble in the capillary tube grew rapidly in the direction of propagation and generated a liquid jet. The maximum penetration depth of this liquid jet into an artificial thrombus increased in proportion to L and reached a maximum value (9 mm) when L was around 13 mm. A shock wave whose overpressure at a point 4 mm away from the catheter exit exceeded 12 MPa was captured by shadowgraph. It was concluded that Ho:YAG laser irradiation within a water-filled catheter caused liquid jet formation, which could penetrate straight into an artificial thrombus. Hence, this jet is expected to promote fibrinolysis by means of injecting fibrinolytics deeply into the thrombus. After resolving some problems, this system will be applied to an endovascular therapy for cerebral embolisms in the near future.

Catheterization↗
PubMed2002

An exonic mutation of the GH-1 gene causing familial isolated growth hormone deficiency type II.

A heterozygous base change was identified in exon 3 of the growth hormone (GH)-1 gene in a Japanese family with autosomal dominant GH deficiency. All of the patients from this family had a heterozygous G to T transversion at the first 5'-site nucleotide of exon 3. Analysis of the GH-1 cDNA, synthesized from lymphoblasts of the patients, revealed an abnormal shorter transcript as well as a normal-sized transcript. Direct sequencing of this abnormal transcript showed that the transcript completely lacked exon 3. In familial isolated GH deficiency (IGHD) type II, several heterozygous mutations have been reported at the donor splice site in intron 3 of the GH-1 gene or inside intron 3, which causes aberrant GH messenger RNA splicing, resulting in the deletion of exon 3. This deletion causes a lack of amino acid residues 32-71 in the mature GH protein. This mutant GH is well-known to exert a dominant negative effect on the secretion of mature normal GH protein. Thus, in the subject family, a heterozygous G-to-T transversion at the first nucleotide of the exon 3 deletes exon 3 in mature GH mRNA and causes GH deficiency. The present authors suggest that the first nucleotide of exon 3 is critical for the splicing of GH-1 mRNA.

Alternative Splicing↗
PubMed2002

Diminution of early insulin response to glucose in subjects with normal but minimally elevated fasting plasma glucose. Evidence for early beta-cell dysfunction.

AIM: Systematic analysis of beta-cell function in Japanese health examinees. METHODS: In 938 Japanese health examinees (627 men and 311 women, mean age and body mass index, 54.0 years and 23.6 kg/m2, respectively), plasma specific insulin was measured at fasting and during a 75-g oral glucose tolerance test. The subjects were stratified into six groups based on fasting plasma glucose < or = 5.1 mmol/l, 5.2-6.0 mmol/l, 6.1-6.9 mmol/l, 7.0-7.8 mmol/l, 7.9-8.7 mmol/l, and > or = 8.8 mmol/l as the 1st, 2nd, 3rd, 4th, 5th and 6th groups, respectively. RESULTS: Distribution of fasting insulin showed a very modest 'inverted U' shape, with the peak in the 5th group. Progressive increase from the 1st toward the 5th group was significant. In contrast, the ratio of change in insulin to change in glucose from 0 to 30 min during the glucose tolerance test was greatest in the 1st group and progressively declined in the groups with higher fasting glycaemia. Difference in the ratio was most striking and highly significant between the 1st and 2nd groups. Distribution of the insulin to glucose ratio of subjects with normal glucose tolerance significantly overlapped with that of untreated patients with diabetes. CONCLUSIONS: In a Japanese population, (i) beta-cell starts to deteriorate during normoglycaemia with a minimal elevation of fasting plasma glucose, and (ii) there are glucose-tolerant subjects with beta-cell dysfunction.

Adolescent↗
PubMed2002

Time-dependent potentiation of the beta-cell is a Ca2+-independent phenomenon.

When isolated rat pancreatic islets are treated with 16.7 mM glucose, a time-dependent potentiation (TDP) of insulin release occurs that can be detected by subsequent treatment with 50 mM KCl. It has been thought that TDP by glucose is a Ca2+-dependent phenomenon and only occurs when exposure to glucose is carried out in the presence of Ca2+. In contrast to this, we now demonstrate TDP under stringent Ca2+-free conditions (Ca2+-free buffer containing 1 mM EGTA). In fact, under these Ca2+-free conditions glucose caused an even stronger TDP than in the presence of Ca2+. TDP induced by glucose in the absence of extracellular Ca2+ was unaffected by inhibitors of protein kinase C (PKC). However, cerulenin or tunicamycin, two inhibitors of protein acylation, eradicated TDP without affecting glucose metabolism. The TDP by glucose was not associated with an increase in the cytosolic free Ca2+ concentration ([Ca2+]i) during subsequent treatment with high K+. Exposure of islets to forskolin under Ca(2+)-free conditions did not cause TDP despite a large increase in the cellular cAMP levels. In conclusion, glucose alone induces TDP under stringent Ca2+-free conditions when [Ca2+]i was significantly lowered. Protein acylation is implicated in the underlying mechanism of TDP.

Acylation↗
PubMed2001

Size-related and size-unrelated functional heterogeneity among pancreatic islets.

Functional heterogeneity of pancreatic islets was systematically analyzed for the first time using freshly isolated single rat pancreatic islets. First, 60 islets were sequentially exposed to 3, 9.4, 15.6, and 24.1 mM glucose for 30 min each in incubation experiments: 36 (60%) responded in a concentration-dependent and 19 (32%) in an all-or-none manner, and 5 (8%) islets did not respond to high glucose. As a group, the larger the islet, the higher the beta cell glucose sensitivity. However, glucose-stimulated elevation of [Ca2+]i in the beta cell. insulin/glucagon ratio in the islet, and expression of glucose transporter 2, glucokinase, and pancreatic duodenal homeobox factor-1 in the beta cell were not significantly related to islet size. Second, 50 islets were stimulated with 16.7 mM glucose in perifusion. A biphasic insulin release was found in 39 (78%), and no or little first phase response in 11 (22%) islets, irrespective of the islet size. Nevertheless, when the response was plotted as a group, it was clearly biphasic. Islet size, insulin content and the amount of insulin release were positively correlated with each other. In conclusion, there are size-related and size-unrelated functional diversity among pancreatic islets. The reason for such heterogeneity remained to be determined.

Animals↗
PubMed2001

Interaction of Myc-associated zinc finger protein with DCC, the product of a tumor-suppressor gene, during the neural differentiation of P19 EC cells.

Expression of the DCC (deleted in colorectal cancer) protein is strongly induced during the neural differentiation of mouse P19 embryonal carcinoma (EC) cells that occurs when these cells are treated with retinoic acid (RA). Myc-associated zinc finger protein (MAZ) is a DNA-binding protein that is widely expressed and functions in human, mouse and hamster cells as an activator, an initiator or a terminator of transcription. However, the biological functions of MAZ remain elusive. We report here that MAZ associates with the cytoplasmic domain of the DCC protein in vivo and in vitro. Yeast two-hybrid assays confirmed this association. An immunofluorescence study demonstrated that DCC protein is expressed at elevated levels in neuron-like P19 EC cells, in particular in axons, in which the MAZ protein is also expressed. We found that MAZ was translocated from the nucleus to the cytoplasm during the RA-induced terminal differentiation of P19 EC cells with resultant loss of the ability of MAZ to bind to the ME1a1 site of the c-myc promoter. Taken together, our observations imply that the DCC protein might play a critical role as a signaling molecule in the regulation of the transcriptional activity of MAZ during the neural differentiation of P19 EC cells.

Active Transport, Cell Nucleus↗