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Biomedical subjects

K Takami

Publications and source records attributed to K Takami.

15 recordsLinked to original sources
PubMed1992

Increase of basic fibroblast growth factor immunoreactivity and its mRNA level in rat brain following transient forebrain ischemia.

We examined the time course of basic fibroblast growth factor (bFGF) immunoreactivity and its mRNA level mainly in the hippocampus after transient forebrain ischemia using immunohistochemistry, enzyme immunoassay (EIA), Western blot analysis and in situ hybridization. Neuronal death in the hippocampal CA1 subfield was observed 72 h after 20 min of ischemia. The number of bFGF-immunoreactive(IR) cells increased 48 h-5 days after ischemia in all hippocampal regions. At 10 and 30 days, the bFGF-IR cells in the CA1 subfield had further increased in numbers and altered their morphology, enlarging and turning into typical reactive astrocytes with the advancing neuronal death in that area. In contrast, the number of bFGF-IR cells in other hippocampal regions had decreased 30 days after ischemia. The EIA study showed a drastic increase in bFGF levels in the hippocampus 48 h after ischemia (150% of that in normal rat) which was followed by further increases. In Western blot analysis, three immunoreactive bands whose molecular weights correspond to 18, 22 and 24 kDa were observed in normal rat and ischemia increased all their immunoreactivities. In the in situ hybridization study of the hippocampus, bFGF mRNA positive cells were observed in the CA1 subfield in which many bFGF-IR cells existed after ischemia. These data demonstrate that transient forebrain ischemia leads to an early and strong induction of bFGF synthesis in astrocytes, suggesting that the role of bFGF is related to the function of the reactive astrocytes which appear following brain injury.

Animals↗
PubMed1992

Effects of fatty acyl-coenzyme A esters on prostaglandin synthesis in rabbit kidney medulla microsomes.

The effects of fatty acyl-coenzyme A (CoA) esters (palmitoyl-, stearoyl-, oleoyl-, linoleoyl- and arachidonoyl-CoA) on the synthesis of prostaglandins (PGs) in rabbit kidney medulla microsomes were examined. Medulla microsomes were incubated with arachidonic acid in 0.1 M-Tris/HCl buffer (pH 8.0) containing reduced glutathione and hydroquinone and the formed PGE2, PGF2 alpha and PGD2 were measured by high-pressure liquid chromatography using 9-anthryldiazomethane for derivatization. Under our incubation conditions rabbit kidney medulla was found to produce PGE2 mainly. The addition of fatty acyl-CoA esters inhibited total PG formation (the sum of PGE2, PGF2 alpha and PGD2) in a dose-dependent manner. Palmitoyl-, stearoyl- and oleoyl-CoA were about 10 times more potent than linoleoyl- and arachidonoyl-CoA as inhibitors of total PG formation. Linoleic acid was slightly more effective than linoleoyl-CoA, while palmitic acid had no influence on PG formation. All the fatty acyl-CoA esters inhibited the formation of PGE2. Simultaneously, the production of PGF2 alpha and PGD2 was increased. These results suggest that the CoA derivatives of palmitic, stearic and oleic acids have the potential to modulate PGE2, PGF2 alpha and PGD2 synthesis by affecting the activities of both-cyclooxygenase and endoperoxide E2 isomerase.

Acyl Coenzyme A↗
PubMed1992

A hole in the T cell repertoire specific for a pigeon cytochrome c related peptide associated with amino acid substitutions on I-Ab molecules.

When C57BL/10(B10) mice were immunized with a pigeon cytochrome c related peptide, 50V (AEGFSYTVANKNKGIT), two helper T cell populations with different specificity were activated. A major T cell population reacted with a 50V analog, 50V54A (AEGFSYTVANKAKGIT), more potently than with the immunogen, 50V, in a heteroclitic fashion, whereas the other minor T cell population responded only to 50V. By contrast, when bm12 mice were immunized with 50V, the minor T cell population responding only to 50V could hardly be demonstrated. The apparent deletion of the minor T cell population in bm12 mice seems to be attributable to negative selection under the influence of I-Abm12 molecules, since the minor T cell population was undetectable in both I-Ab and I-Abm12 restricted T cells from (B10 x bm12)F1 mice. Thus, three mutant points on the I-A molecule in bm12 mice appear to be involved in the seemingly negative selection of the certain T cell repertoire. The present finding demonstrates that a T cell repertoire generated under the influence of a MHC product (Ab) on one parental strain is eliminated by a different MHC product (Abm12) on the other parental strain of F1 cross. The mechanism underlying the apparent negative selection is discussed.

Amino Acid Sequence↗
PubMed1992

Functional evaluation by gait analysis of various ankle-foot assemblies used by below-knee amputees.

Twelve different prosthetic feet were tested by 10 male subjects with right below-knee amputations. Level walking with each prosthetic foot was investigated using a pair of force plates. Five parameters were selected to compare the functional characteristics of the feet: 1) step length, 2) walking velocity on the sound side in relation to the prosthetic side, 3) depth of valley in the pattern of the vertical component of the floor reaction force, 4) efficiency of the deceleration and acceleration by the prosthetic foot, and 5) irregular patterns in the wave form of the fore and aft components of the floor reaction force. Each of the above parameters was rated numerically. The total score of the objective evaluation attained by analysing the five parameters showed some coincidence to the results of subjective evaluation. However, a good correlation existed between the objective negative score and the subjective negative rating (p < 0.05). Non-axial feet developed recently, such as the SAFE II and Seattle Light feet achieved higher scores in the older age group, while single-axis feet, such as the LAPOC and Otto Bock feet achieved higher scores in the younger age group (p < 0.05).

Adult↗
PubMed1991

Increase in basic fibroblast growth factor-like immunoreactivity in rat brain after forebrain ischemia.

Using immunohistochemical techniques, a study was conducted to determine whether basic fibroblast growth factor (bFGF) is generated as one of the 'self-repair' responses in rat brain following transient forebrain ischemia. In normal brain, slight bFGF-like immunoreactivity was observed. However, in rats exposed to 20 min of forebrain ischemia, intense bFGF-like immunoreactivity was observed in the CA1 subfield of the hippocampus and the caudate putamen, and marked activity was evident in the temporal cortex, corpus callosum and the CA4 subfield of the hippocampus. Marked neuronal degeneration was also observed in these brain regions following forebrain ischemia. These results suggest that induction of bFGF-like immunoreactivity may be related to the healing which follows brain ischemia.

Animals↗
PubMed1991

Effects of a proton pump inhibitor, AG-1749 (lansoprazole), on reflux esophagitis and experimental ulcers in rats.

The effects of (+/-)-2-[[[3-methyl-4-(2,2,2-trifluoroethoxy-2- pyridyl]methyl]sulfinyl]-1H-benzimidazole (lansoprazole, AG-1749) and famotidine on various experimental ulcers in rats were compared. AG-1749 inhibited reflux esophagitis; gastric lesions induced by water-immersion stress, aspirin or ethanol; and duodenal ulcers induced by cysteamine or mepirizole in a dose-dependent manner: the ID50 values were 0.7, 2.4, 0.7, 8.5, 1.1 and 0.3 mg/kg, p.o. or i.d., respectively. Famotidine inhibited reflux esophagitis with an ID50 value of 12.9 mg/kg, but did not cause 50% inhibition of ethanol-induced gastric lesions even at 100 mg/kg, although it showed almost the same or a little stronger potency on other experimental ulcers: ID50 values were 0.3-1.4 mg/kg. Significant aggravation of ethanol- or water-immersion stress-induced lesions was observed in rats given famotidine at 30 mg/kg twice daily for 4 days, but not in rats given AG-1749 at 10 mg/kg twice daily. Administration of AG-1749 for 14 consecutive days markedly accelerated the healing of acetic acid-induced gastric and duodenal ulcers, and the healing effect was significant at 10 and 30 mg/kg/day, p.o. Famotidine also accelerated the healing of ulcers, but its potency was less than that of AG-1749. The results of this study indicate that although AG-1749 is slightly less potent than famotidine in inhibiting acutely induced gastroduodenal lesions, this agent is superior to famotidine in promoting the healing of ulcers and in inhibiting reflux esophagitis and ethanol-induced gastric lesions.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1991

Effect of thyrotropin-releasing hormone (TRH) in experimental spinal cord injury: a quantitative histopathologic study.

Spinal cord injuries in rats were experimentally produced by compressing the cord (T11 vertebra level) for 60 min with stainless steel screws. Morphometric analysis of the injured cord revealed that at 14 days post-injury, there were significant correlations between the neurologic score (NS) and all morphometric parameters, including total cross-sectional area (rs = 0.438), lesioned area (rs = -0.421) and area of the gray (rs = 0.377) and white matter (rs = 0.704). Although rats treated with thyrotropin-releasing hormone (TRH; 22.5 mg/kg, s.c., twice daily for 7 days starting 24 hr post-injury) showed significant improvement in NS 14 days post-injury, there were no significant differences in morphometric parameters between saline- and TRH-treated rats. In addition, no significant correlation was observed between NS and any of the morphometric parameters in TRH-treated rats, even though there was a significant correlation between the area of white matter and NS in saline-treated rats. These results suggest that neurologic recovery closely reflects the histopathological changes evident at the injury site in the present model, and that the improvement of neurologic status seen in rats with cord injury given TRH starting 24 hr post-injury is not due to protection against progression of neural damage at the injury site.

Animals↗
PubMed1988

Sites of origin of ventricular premature beats in patients with and without cardiovascular disease evaluated by body surface mapping.

The site of origin of ventricular premature beats (VPBs) was estimated by QRS maps and its distribution in two patient groups was studied. VPB origin was determined by comparing the body surface map of VPBs with that during electrical stimuli applied at various sites of the ventricle. Subjects were 100 patients without obvious underlying cardiovascular disease (Group N) and 289 patients with various heart diseases (Group D). Nine sites of origin of VPB were identified. In group N, VPBs of right ventricular origin were noted in 69%, those of left ventricular origin in 6%. There was a relatively high incidence of VPBs with foci estimated to be the divisions of the left bundle branch, and the age of patients with these VPBs was young. In Group D, VPBs of left ventricular origin showed a higher incidence (34.6%) and those of right ventricular origin a lower incidence (41.2%) than those in group N. The data suggest that VPBs originating from the apex and base of the ventricle strongly indicate the presence of basic heart disease and that VPBs originating in or near the divisions of the left bundle branch in younger subjects do not necessarily indicate cardiac disease.

Adolescent↗
PubMed1985

Distribution of calcitonin gene-related peptide in the rat peripheral nervous system with reference to its coexistence with substance P.

This immunocytochemical study, using a double-staining method, showed that calcitonin gene-related peptide-like immunoreactive structures are widely distributed in the peripheral nervous system and that many of them coexist with substance P-like immunoreactive structures in single sensory ganglion cells. Neurons positive for calcitonin gene-related peptide but negative for substance P were detected in sensory ganglia. These cells were large (about 30-45 micron in diameter); these primary sensory neurons containing calcitonin gene-related peptide can probably act independently of substance P. There were neurons containing calcitonin gene-related peptide without substance P in the pterygopalatine ganglion, although these cells were less numerous than in the sensory ganglia. In consecutive sections, calcitonin gene-related peptide-like structures occurred in thyroid parafollicular cells, which also contain calcitonin. This suggested that messenger RNA for producing calcitonin gene-related peptide is also present in the thyroid, and like calcitonin, calcitonin gene-related peptide may have a peripheral physiological role.

Animals↗
PubMed1985

[Ventricular activation sequence estimated by body surface isochrone map].

This study was performed to evaluate the usefulness of the body surface isochrone map (VAT map) for identifying the ventricular activation sequence, and it was correlated with the isopotential map. Subjects consisted of 42 normal healthy adults, 18 patients with artificial ventricular pacemakers, and 100 patients with ventricular premature beats (VPB). The sites of pacemaker implantations were the right ventricular endocardial apex (nine cases), right ventricular epicardial apex (five cases), right ventricular inflow tract (one case), left ventricular epicardial apex (one case), and posterior base of the left ventricle via the coronary sinus (two cases). An isopotential map was recorded by the mapper HPM-6500 (Chunichi-Denshi Co.) on the basis of an 87 unipolar lead ECG, and a VAT isochrone map was drawn by a minicomputer. The normal VAT map was classified by type according to alignment of isochrone lines, and their frequency was 57.1% for type A, 16.7% for type B, and 26.2% for type C. In the VAT map of ventricular pacing, the body surface area of initial isochrone lines represented well the sites of pacemaker stimuli. In the VAT map of VPB, the sites of origin of VPB agreed well with those as determined by the previous study using an isopotential map. The density of the isochrone lines suggested the mode of conduction via the specialized conduction system or ventricular muscle. The VAT map is a very useful diagnostic method to predict the ventricular activation sequence more directly in a single sheet of the map.

Bundle-Branch Block↗