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Biomedical subjects

H Takamiya

Publications and source records attributed to H Takamiya.

At least 19 recordsLinked to original sources
PubMed2001

(1)H double-quantum filtered MR imaging of joints tissues: bound water specific imaging of tendons, ligaments and cartilage.

The (1)H double-quantum filtered (DQF) NMR and DQF MRI is applied to the joint tissues of rabbits for selective visualization of tendons, menisci and articular cartilage. The (1)H DQF NMR selectively filters double-quantum coherence arising from the (1)H dipolar interaction of the "bound" water in these tissues. The double-quantum creation time dependency of the DQF signal intensity is determined by the molecular environment of the "bound" water. Therefore, each tissue has a unique creation time at which the DQF signal reaches its maximum intensity, tau(max) (Achilles tendon: 0.46 +/- 0.02 ms, patella: 0.55 +/- 0.8 ms, anterior cruciate ligament: 0.60 +/- 0.05 ms, meniscus: 0.78 +/- 0.02 ms, skin: 0.81 +/- 0.07 ms). We have presented the creation-time-contrasted DQF images of the meniscus, patella, foot, and knee joint. Compared with conventional T(2)*-weighted gradient-echo (GRE) MR images, tendons, ligaments, menisci, and articular cartilage were more clearly seen in the DQF MR images. All these tissues were distinctly discriminated from each other by their creation times. DQF MR images of foot and knee joints can selectively demonstrated tendons, ligaments, and cartilage, which make it easier to understand the complicated anatomic structure of joints. Because the DQF NMR signal intensity and tau(max) are sensitive to the order structure of the "bound" water, it might be possible to introduce the creation-time dependent-contrast of (1)H DQF MR images as a new tool for analyzing the changes in the ordered structure of the tissue.

Animals↗
PubMed2001

Linker chain effect of ferrocenyl naphthalene diimide on a double stranded DNA preference.

Naphthalene diimide derivative 1 carrying two 3-(ferrocenyl-methylamino)-propyl substituents was synthesized as a new hybrid indicator for electrochemical gene sensing. Ligand 1 showed a preference for double stranded DNA four-times larger than 2 previously described. The peak potential of 1 shifted 30 mV toward the negative side from that of 2, thereby shortening the time required for gene detection.

Biosensing Techniques↗
PubMed2000

Characteristics of proton NMR T(2) relaxation of water in the normal and regenerating tendon.

The molecular behavior of water in normal and regenerating tendons was analyzed using the transverse relaxation time (T(2)) measured by spin-echo proton nuclear magnetic resonance ((1)H-NMR) spectroscopy at 2.34 T (25 degrees C). A section of the Achilles tendon was dissected from an anesthetized Japanese white rabbit, and its longitudinal axis was oriented at 0, 35, 54.7, 75, and 90 degrees to the static magnetic field. In the normal tendon, the T(2) relaxation of water presented biexponential relaxation and anisotropy in both the long T(2) (5.41 to 6.21 ms) and short T(2) (0.41 to 1.43 ms) components, in which the greatest values were obtained at 54.7 degrees. However, the range of the anisotropy was much narrower than we expected from the (1)H dipolar interaction of water bound to the collagen fibers in the tendon. The apparent fractions of water proton density also varied with orientation: the fraction of the longer T(2) components was at its maximum at 54.7 degrees. These results suggest that a simple two-compartment model could not be applicable to orientational dependency of the T(2) value of the tendon, and the well ordered water in the short T(2) relaxation component may show an elongated T(2) relaxation time that falls in the range of the long T(2) relaxation component at 54.7 degrees. This hypothesis can explain both the narrower range of the T(2) relaxation time and the orientational dependency on the apparent fraction of (1)H density. Regenerating processes of the Achilles tendon were followed for 18 weeks by analyzing the T(2) relaxation time. There is only a long T(2) relaxation time component (21.8 to 28.0 ms) up to 3 weeks after transection. Biexponential relaxation is revealed at 6 weeks and thereafter, whereby (i) the T(2) relaxation times become shorter, (ii) there is anisotropy in the short and long T(2) values, and (iii) the orientational dependency of the apparent fraction of water proton density becomes evident with maturation of the regenerating tendon. From these results, the (1)H T(2) relaxation time of water might be used to monitor the healing process of collagen structures of the tendon non-invasively.

Animals↗
PubMed1999

1H double-quantum-filtered MR imaging as a new tool for assessment of healing of the ruptured Achilles tendon.

1H double-quantum-filtered magnetic resonance imaging (DQF MRI) was applied to monitor the healing process of the Achilles tendons in rabbits after tenotomy. DQF MRI provides a new contrast, which is based on the non-zero average of the dipolar interaction caused by anisotropic motion of water molecules, determined mainly by their interaction with the ordered collagen fibers. Tissues are characterized by the dependence of their DQF signal on the DQ creation time, tau. With the use of DQF MRI, higher tissue contrast is obtained between tendon, bone, skin, and muscle. The tendons, which give weak signals in standard MRI techniques, are highlighted in the (1)H DQF image. The image changed dramatically during the healing process of the injured Achilles tendon. These changes matched the phases of the healing process. By using a tau-weighted contrast, the DQF images indicate the part of tendon that has not completely healed, even after the conventional MRI appeared normal. Magn Reson Med 42:884-889, 1999.

Achilles Tendon↗
PubMed1999

Effect of an exercise-heat acclimation program on body fluid regulatory responses to dehydration in older men.

We examined if an exercise-heat acclimation program improves body fluid regulatory function in older subjects, as has been reported in younger subjects. Nine older (Old; 70 +/- 3 yr) and six younger (Young; 25 +/- 3 yr) male subjects participated in the study. Body fluid regulatory responses to an acute thermal dehydration challenge were examined before and after the 6-day acclimation session. Acute dehydration was produced by intermittent light exercise [4 bouts of 20-min exercise at 40% peak rate of oxygen consumption (VO(2 peak)) separated by 10 min rest] in the heat (36 degrees C; 40% relative humidity) followed by 30 min of recovery without fluid intake at 25 degrees C. During the 2-h rehydration period the subjects drank a carbohydrate-electrolyte solution ad libitum. In the preacclimation test, the Old lost approximately 0.8 kg during dehydration and recovered 31 +/- 4% of that loss during rehydration, whereas the Young lost approximately 1.2 kg and recovered 56 +/- 8% (P < 0.05, Young vs. Old). During the 6-day heat acclimation period all subjects performed the same exercise-heat exposure as in the dehydration period. Exercise-heat acclimation increased plasma volume by approximately 5% (P < 0.05) in Young subjects but not in Old. The body fluid loss during dehydration in the postacclimation test was similar to that in the preacclimation in Young and Old. The fractional recovery of lost fluid volume during rehydration increased in Young (by 80 +/- 9%; P < 0.05) but not in Old (by only 34 +/- 5%; NS). The improved recovery from dehydration in Young was mainly due to increased fluid intake with a small increase in the fluid retention fraction. The greater involuntary dehydration (greater fluid deficit) in Old was accompanied by reduced plasma vasopressin and aldosterone concentrations, renin activity, and subjective thirst rating (P < 0.05, Young vs. Old). Thus older people have reduced ability to facilitate body fluid regulatory function by exercise-heat acclimation, which might be involved in attenuation of the acclimation-induced increase in body fluid volume.

Acclimatization↗
PubMed1998

A case of late onset primary hyperoxaluria type I (PH-I) presented with black liver.

A 63-year-old woman who had received hemodialysis therapy since she fell acute on chronic renal failure 4 years ago presented with multiple joint pain. Nephrocalcinosis was not detected by abdominal X-ray when hemodialysis therapy was initiated. Laboratory testing showed azotemia, anemia, hypoproteinemia and mild liver dysfunction but no liver cirrhosis. Biopsied bone tissue demonstrated numerous calcium oxalate crystal depositions. Laparoscopy revealed black liver in macroscopic view. Histological studies showed numerous lipofuscin-like dark brown granules were deposited in hepatocytes. The activity of alanine : glyoxylate aminotransferase (AGT) was less than 0.1 U/g in biopsied patient's liver tissue. Generally, clinical symptoms demonstrated by Japanese primary hyperoxaluria type I (PH-I) patients are milder than those of European patients. Some PH-I patients may successfully avoid urinary tract calcification unless they fall into oliguria by some other causes. The lipofuscin granules are most likely the source of the dark color. Massive deposition of the lipofuscin granules indicated that the duration of the liver metabolic abnormality had lasted for long time. Thus, black liver may be related to a mild form of PH-I.

Biopsy↗
PubMed1997

Gastrectomy with combined resection of other organs for carcinoma of the stomach with invasion to adjacent organs: clinical efficacy in a retrospective study.

BACKGROUND: Carcinoma of the stomach invading one or more adjacent organs raises serious concerns over en bloc dissection because en bloc resection has an associated high risk and such advanced carcinoma is frequently associated with incurable factors. Thus, it is important to understand the efficacy of gastrectomy combined with other organ resection and to refine the indications for en bloc dissection. STUDY DESIGN: Seventy-seven patients with carcinoma of the stomach directly invading adjacent organs or structures were analyzed retrospectively to investigate the efficacy of en bloc resection. Forty-one patients underwent gastrectomy combined with resection of one or more invaded organs (combined resection group), while the other 36 patients underwent gastrectomy with palliative abrasion between the primary tumor and the invasion site (noncombined resection group). RESULTS: The five-year survival rate was 23 percent in the combined resection group and 0 percent in the noncombined resection group (p < .05). The 23 curative cases and 18 noncurative cases in the combined resection group had a survival rate of 41 percent and 0 percent, respectively (p < .05). The survival rate after a single organ resection was 29 percent, and after a multiple organ resection, 0 percent (p < .05). Cases of carcinoma invading either the pancreas or mesocolon had a slightly but not significantly better prognosis. In Borrmann type IV carcinoma there was no difference in survival between the curative and noncurative operation. Cases with P1 dissemination had a better prognosis than those of P2 and P3 dissemination. CONCLUSIONS: The best indication for an en bloc combined organ resection was an invasion limited to only one other organ, not more than N2, no incurable factor, and any type except Borrmann type IV. Additionally, an en bloc combined resection would be worth trying for any type of gastric carcinoma with not more than P1 dissemination and with no other incurable factor.

Carcinoma↗
PubMed1997

[The significance of p21 expression in gastric cancer].

We examined the expression of p53, p21, cyclin D1, E, and PCNA in 75 cases of gastric cancer by immunohistochemical study and the expression of p21 RNA in cases by in situ hybridization. The rate of stage III, IV cases of p53(+) p21(-) group was significantly higher than that of any other groups. The apportinately 3-year survival rate of p53(+) p21(-) group was significantly lower than either that of p21(+) p53(-) or p53(-) p21(-) group. The 3-year survival rates of positive cases were significantly lower than those of negative cases on both cyclin D1 and E. The positive rate of cyclin E of the p53(-) p21(+) group was significantly lower than that of the p53(+) p21(-) group. The average PCNA Labeling. Index (LI) of the p53(+) p21(-) group was significantly higher than that of the p53(-) p21(+) group. The 3-year survival rate of cases with expression of p21 RNA was higher than that of cases without p21 RNA. Average PCNA L1 of cases with expression of mutant-type p53 was high and the number of poor prognostic cases in cases with expression of mutant-type p53 was large. In contrast, the average PCNA LI of cases with expression of p21 was low and the number of good prognostic cases with expression of p21 was large. These results suggest that p21 suppresses synthesis of DNA via cyclin E and PCNA.

Cyclin D1↗
PubMed1996

Remnant-stump early gastric cancer following partial gastrectomy.

Eight rare cases of remnant-stump early gastric cancer (RS-EGC) were investigated, retrospectively. The incidence of RS-EGC was 0.9% (8/845) of all resected early gastric cancers. The macroscopic cancer type was elevated in 75% and mucosal in 88%. All were the differentiated type with no lymph node metastasis. The initial reconstruction involved a Billroth II in 75% of the patients. The RS-EGC was usually found during a periodic endoscopic follow-up. All patients are still alive with no postoperative complications and no cancer recurrence.

Aged↗
PubMed1996

A clinicopathological study of distal advanced gastric carcinoma with duodenal invasion.

We studied retrospectively the clinicopathological features of gastric cancer with duodenal invasion and compared these with those with non-invasion, to investigate the prognostic significance of duodenal invasion. The patients were grouped into two groups of Group A (65 patients) with duodenal invasion and Group B (197 patients) without invasion who underwent gastrectomy for advanced distal gastric carcinoma according to histological findings. In Group A, many were at high age and with symptoms of pyloric stenosis. Group A (91%) had a significantly higher incidence of serosal invasion and infiltration into the pancreas head than did Group B (76%) (p < 0.01). In N3 metastasis, there was a significant difference between Group A (60%) and Group B (36%) (p < 0.01). The five-year-survival rate in Group A was 14.0% and in Group B was 43.3% (p < 0.001). In cases of duodenal invasion, patients with symptoms of pyloric stenosis demonstrated a poorer prognosis than those without. Those with longer than 20 mm invasion had a significantly higher incidence of N3 metastasis than those with less than 10 mm (p < 0.05). Lymphangitic type had longer invasive length to duodenum, and N3 metastasis of the lymphangitic type was frequent comparing to localized type (42%) and invasive type (47%) (p < 0.001) (95%) (p < 0.01). These results showed that duodenal invasion was a significant prognostic factor in cases of distal gastric carcinoma. In the therapeutic strategy for advanced gastric carcinoma with duodenal invasion, it is necessary to perform gastrectomy with regional lymph nodes dissection and with combined resection of adjacent organs.

Aged↗
PubMed1996

[Immunohistochemical analysis of c-erB-2 and nm23 expression in early gastric carcinoma].

The expression of c-erB-2 and nm23 genes product were investigated immunohistochemically in 108 resected cases of early gastric cancer. The expression rate of c-erB-2 was significantly higher in the cases of submucosal cancer or in the cases with lymph node metastasis. The expression rate of c-erB-2 was higher in the metastatic tumor than in the primary tumor. There was no significant correlation between the expression of nm23 and depth of invasion. The expression rate of nm23 was lower in the cases with lymph node metastasis than in the cases without lymph node metastasis. The expression could not be found in the metastatic tumor. These results suggest that there would be correlation between the expression of c-erB-2 and depth of invasion and lymph node metastasis, and the nm23 may suppress metastatic potential in early gastric cancer.

Humans↗
PubMed1995

[Molecular differential diagnosis of herpes virus using common primer pairs: detection of HSV-1, HSV-2, VZV and CMV by the PCR].

Differential diagnosis of herpes virus species is often required in various clinical courses, such as transplantation and immunocompromised patients. Pairs of common primers which enabled sufficient amplifying and differential diagnosis of herpes virus species were designed and nested PCR using the common primer pairs was conducted to evaluate for its clinical application. The PCR was shown to provide amplification and differential diagnosis of HSV-1, HSV-2, VZV and CMV. The results of the PCR were consistent with those from fluorescent antibody of herpes virus culture and isolation. From clinical vesicular specimens, the PCR enabled the direct detection of HSV-1, HSV-2, and VZV. The PCR using the common primer pairs offers speed in the differential diagnosing of herpes virus.

Base Sequence↗
PubMed1994

Sudden deafness accompanied by asymptomatic mumps.

In this study we investigated asymptomatic mumps as a possible cause of sudden deafness. We studied 131 sudden deafness patients by measuring their serum mumps antibody values. Positive IgM antibody results, which strongly suggest recent mumps infection, were revealed in 9 of the 130 patients tested (6.9%). Asymptomatic mumps infections are apparently closely related to sudden deafness. Further studies will provide more definite diagnoses of mumps deafness and might be applicable to the treatment of such hearing loss.

Adolescent↗
PubMed1992

Morphology of the kidney of the platypus (Ornithorhynchus anatinus: Monotremata).

The platypus kidney shows morphological similarities to those of other mammals. Macroscopically, the cortex is easily distinguishable from the fairly wide medulla. Within the medulla, no clear border is observed between the inner and outer zones. Light and transmission electron microscopically, the glomeruli show quite similar architecture to those of other mammals; however, the glomerular lobulation is very clear. The glomerular tufts are rather simple, but capillary lumen varies widely in size, which is one of the unique features of the platypus kidney. The urinary tubule is generally similar to that of human and other mammals in shape and segmentation; however, the staining specificities of histochemical reactions and the shape of epithelial cells of the Henle's loop differ from those of other mammals. The most conspicuous features are: 1) although no protein casts are found in the tubular lumina, epithelial cells of the proximal convoluted tubule (PCT) have numerous electron-dense vesicles as in human nephrotic kidneys; and 2) the platypus Henle's loop consists of the thick epithelial cells similar to the mammalian type nephron of birds. As compared to those of other mammals such as humans and rats, our observations suggest that the platypus kidney is less developed, in terms of evolution.

Animals↗
PubMed1992

[Detection of cytomegalovirus in urine specimens from renal transplant recipients using polymerase chain reaction].

Human cytomegalovirus (CMV) in this study, a polymerase chain reaction (PCR) assay was developed to detect human cytomegalovirus (CMV) from urine specimens taken from renal transplant patients and one congenital CMV infection. Twenty eight urine specimens of 20 renal transplant patients were analyzed by the PCR. CMV infection was detected in 11 specimens (8 recipients). The incidence (40.0%) of PCR positive in the renal transplant patients was highest among the other conventional methods including fluorescent antibody study, anti-IgM EIA and complement fixation test. In two cases, CMV infection could be identified by PCR before antibody development. The PCR procedure is more sensitive and rapid than conventional methods for the diagnosis of CMV. Rapid diagnosis of CMV infection using PCR may be useful in clinical diagnosis and have therapeutic value.

Adult↗