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N Fujiwara

Publications and source records attributed to N Fujiwara.

At least 127 records · Page 7Linked to original sources
PubMed1992

Changes in intracellular pH of mouse hippocampal slices responding to hypoxia and/or glucose depletion.

Effects of hypoxia and/or glucose depletion on apparent intracellular pH, (pHi)app, were studied in hippocampal slices of mouse brain using the fluorescence pH indicator BCECF (2',7'-bis(carboxyethyl)carboxyfluorescein). In the presence of glucose (11 mM), (pHi)app of the CA1 pyramidal cell layer decreased with hypoxia but rapidly recovered with reoxygenation. The response in (pHi)app to hypoxia was consistent with changes in lactate content. By superfusion with a hypoxic and glucose-devoid solution, (pHi)app decreased in the first 5 min, but then increased in two phases: during a 5- to 7-min period and again during the latter period of superfusion. BCECF fluorescence rapidly diminished in this latter period. These changes in (pHi)app could not be explained only by the lactate content in the slices. Some other mechanisms may also regulate the (pHi)app in the slices during and after hypoxia and glucose depletion.

Animals↗
PubMed1992

Postcataract against-the-rule astigmatism after phacoemulsification procedure. Characteristic changes over time.

To further determine whether postoperative astigmatism is related to the amount of preoperative astigmatism, we analyzed two types of against-the-rule (AR) astigmatism induced by phacoemulsification and aspiration (PEA) procedures. The operations all utilized 10-0 polyester (Mersilene) in double running fashion for the closure of the corneoscleral incisions. The induction and spontaneous regression of several types of astigmatism were analyzed over 6 months. Surgery was all done by one surgeon, with the same surgical procedure and the same number of sutures. In postoperative AR astigmatism less than 0.7 D at 6 months, although the amount of the astigmatism 1 week postoperatively was remarkably increased (2.66 +/- 0.17 D), postoperative astigmatism was decreased 6 months following surgery. On the other hand, in postoperative AR astigmatism greater than 1.5 D at 6 months, the power of the astigmatism 1 week postoperatively (2.12 +/- 0.13 D) was not much higher than the preoperative level (1.38 +/- 0.08 D), but tended to continue increasing even 6 months after surgery. There was no difference in the power of astigmatism between 1 and 3 months postoperatively. The eyes with preoperative astigmatism (e.g. 1.38 +/- 0.08 D) and especially preoperative AR astigmatism (e.g. 1.60 +/- 0.11 D), showed an increase of their astigmatism after the PEA procedure. We discussed some risk factors which may induce greater postoperative AR astigmatism.

Astigmatism↗
PubMed1992

Effects of dorsal root entry zone lesions on CSF and plasma neuropeptides and catecholamines.

Effects of dorsal root entry zone lesions (DREZLs) on cerebrospinal fluid (CSF) and plasma concentrations of neuropeptides, catecholamines, and cyclic nucleotides were studied in 9 patients with intractable chronic pain. Contents of beta-endorphin-like-material in CSF decreased in all patients 12-17 days following DREZLs during which complete to good pain relief was achieved. Contents of beta-endorphin-like-material in CSF increased again about one month after DREZLs in two and remained unchanged in one of three patients tested, who complained of partial reappearance of pain. Contents of beta-endorphin-like-materials in plasma showed no significant changes after DREZLs. Substance P, noradrenaline, adrenaline, and cyclic nucleotide levels in both CSF and plasma were variable among the subjects and did not change significantly following the operations. Thus, the results suggest that production of beta-endorphin-like-material in the central nervous system is decreased by DREZL, though the increase in its turn-over might not be neglected. The mechanisms of the decrease in contents of beta-endorphin-like-material in CSF after DREZLs were discussed in terms of our current knowledge of pain and pain inhibitory systems.

Adult↗
PubMed1992

Characterization of two novel pyruvylated glycosphingolipids containing 2'-aminoethylphosphoryl(-->6)-galactose from the nervous system of Aplysia kurodai.

Two novel acidic glycosphingolipids containing pyruvylated galactose were purified from the nervous tissue of Aplysia kurodai by successive Iatrobeads column chromatographies. By component analysis, sugar analysis, permethylation studies, fast atom bombardment-mass spectrometry, and proton magnetic resonance spectrometry, the structures of these acidic glycosphingolipids, named F-9 and FGL-I, were determined to be: [3,4-O-(S-1-carboxyethylidene)]Gal beta 1-->3 GalNAc alpha 1-->3[6'-O-(2-aminoethylphosphonyl)Gal alpha 1-->2] (2-aminoethylphosphoryl 1-->6)Gal beta 1-->4Glc beta 1-->1ceramide and [3,4-O-(S-1-carboxyethylidene)] Gal beta 1-->3GalNAc alpha 1-->3(Fuc alpha 1-->2)(2-aminoethylphosphonyl-->6 Gal beta 1-->4Glc beta 1-->1ceramide, octadeca-4-sphingenine and anteisononadeca-4-sphingenine. Thus, pyruvylated glycosphingolipids containing phosphoethanolamine in addition to or in place of 2-aminoethylphosphonate are present in the nervous system of Aplysia.

Acidic Glycosphingolipids↗
PubMed1992

Effects of pentobarbital on heterosegmentally activated dorsal root depolarization in the rat. Investigation by sucrose-gap technique in vivo.

Slow positive cord dorsum (P-) potentials activated by segmental stimulation are believed to reflect primary afferent depolarizations and have been shown to be augmented by barbiturates. However, there have been no data to confirm whether heterosegmentally activated P-potentials also represent primary afferent depolarizations and are similarly affected by barbiturates. We therefore tested whether heterosegmental P-potentials reflect primary afferent depolarizations and how these heterosegmental potentials are affected by barbiturates. Heterosegmentally activated dorsal root (DR) depolarizations (depolarizations evoked in DRs of lumbar segments in response to afferent volleys to cervical segments produced by electrical stimulation of the forepaw) and P-potentials were simultaneously recorded, adapting the sucrose-gap technique for recording DR depolarization in vivo in the rat. Forepaw (heterosegmental) stimulations produced a large depolarization in the DRs of L5-S1 as well as a slow P-potential in the lumbosacral enlargement. Transection of the spinal cord at the level of C1-C2 abolished both the P-potential and DR depolarization activated by heterosegmental stimulation as well as the second component of segmentally (hind-paw) activated P-potential. Bicuculline (100 micrograms/kg, intravenous) augmented the P-potential and DR depolarization produced by heterosegmental stimulation, but larger doses, 400-600 micrograms/kg, eventually suppressed these. However, the drug, in a dose-dependent manner, suppressed both the P-potential and DR depolarization produced by the segmental stimulation. Pentobarbital (10-40 mg/kg, intravenous) suppressed in a dose-dependent manner both the heterosegmental P-potential and heterosegmental DR depolarization and prolonged their peak latencies. By contrast, pentobarbital augmented and prolonged the segmental P-potential and segmental DR depolarization.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Sudden against-the-rule astigmatism 6 months after intraocular lens implantation with the Kelman phacoemulsification procedure: 4 of 809 cases.

Of 809 eyes that underwent the Kelman phacoemulsification and aspiration (KPE) procedure, we report on 4 patients (0.49%) who developed sudden against-the-rule (AR) astigmatism after intraocular lens implantation. These patients had had with-the-rule astigmatism preoperatively to 3 months postoperatively and suddenly developed AR astigmatism 6 months after surgery. To study the development and progression of AR astigmatism in these patients (group A), we compared their 6-month time course with that of 257 patients (group B) with postoperative AR astigmatism. In group A, the degree of astigmatism was not significantly different from group B astigmatism preoperatively (1.03 +/- 0.16 vs. 1.04 +/- 0.04 dptr) and 6 months postoperatively (1.32 +/- 0.13 vs. 1.26 +/- 0.05 dptr). However, 1 week postoperatively, the astigmatism of the 4 cases was much greater (5.72 +/- 0.14 dptr) than that of the others (2.32 +/- 0.07 dptr). These rare 4 cases, which had no other unusual characteristics, are indicative of the importance of a careful follow-up even if the post-KPE course seems uneventful.

Aged↗
PubMed1992

Outcome of preoperative against-the-rule astigmatism after phacoemulsification: characteristic changes over time. Part II.

To determine the outcome of preoperative against-the rule (AR) astigmatism among 1,648 phacoemulsification and aspiration (PEA) procedures, we analyzed the post-cataract time course of astigmatism over 6 months in 618 eyes divided into three groups. In preoperative AR astigmatism less than 0.75 dptr (n = 208), the astigmatism increase 1 week postoperatively was rapid. In preoperative AR astigmatism greater than or equal to 1.5 dptr (n = 185), no difference in the power of astigmatism was apparent between 1 and 3 months postoperatively. The third group (0.75 less than or equal to preoperative AR astigmatism less than 1.5 dptr, n = 143) showed intermediate characteristics. The eyes with preoperative low AR astigmatism showed exacerbation of astigmatism after the PEA procedure, whereas the degree of astigmatism, corneal curvatures and the rate of AR astigmatism became lower in the eyes with higher preoperative AR astigmatism.

Aged↗
PubMed1992

[Digital imaging microscopy for intracellular Ca2+ in cultured single rat vascular smooth muscle cells using fluorescent Ca2+ indicator "fura-2"].

We presented the principle and methodology of digital imaging microscopy for intracellular Ca2+ in cultured single vascular smooth muscle cells of the rat using fluorescent Ca2+ indicator "fura-2". The methods seemed useful for studying the physiological and pathological phenomena in a single smooth muscle cell. Analysis of the spatial and temporal dynamics of intracellular Ca2+ might be crucial for studying the active sites of vasoactive or anesthetic drugs in a vascular smooth muscle cell as well as for understanding pathophysiology of the arterial spasm.

Animals↗
PubMed1992

Remarkable postcataract against-the-rule astigmatism after phacoemulsification in 83 of 809 cases.

We analyzed 83 cases of remarkable postcataract against-the-rule (AR) astigmatism (greater than 1.5D) occurring in a total of 809 Kelman's phacoemulsification aspiration procedures, all using 10-0 polyester sutures in a double-running fashion to close the corneoscleral incisions. All operations were done by one surgeon, using the same surgical procedure and the same number of sutures. The induction and spontaneous regression of several types of astigmatism were analyzed over six months. In cases of preoperative oblique and AR astigmatism, shifts (2.09 +/- 0.22D, 1.93 +/- 0.13D, respectively) after the first week were much smaller than those of preoperative with-the-rule astigmatism. Thereafter, degrees of oblique and AR astigmatism increased and remained higher even six months after surgery. The induction and spontaneous regression of postoperative AR astigmatism was similar to that of oblique astigmatism. Compression of the lids on the eye may be a more important factor than previously considered.

Aged↗
PubMed1991

Differential effects of protein kinase C activation on catecholamine secretions evoked by stimulations of various receptors in the rat adrenal medulla.

Catecholamine secretions during continuous receptor stimulations by histamine, muscarine and bradykinin in the rat adrenal medulla commonly consisted of two phases, a transient initial secretion followed by a sustained secretion. On activating protein kinase C (PKC) by phorbol dibutyrate (PDBu), both phases of histamine-evoked secretion were inhibited whereas the initial phase alone was inhibited with muscarine. In contrast, bradykinin-evoked secretion as a whole was potentiated. Similar modes of modulations were exhibited when the secretions with these agonists were elicited in muscarine- or bradykinin-pretreated medullae in which PKC had been activated by endogenous processes. It is suggested that PKC may selectively affect the receptors or/and GTP-binding proteins to cause the differential effects on the secretory response in the rat adrenal medulla.

Adrenal Medulla↗
PubMed1991

Structure of triphosphonoglycosphingolipid containing N-acetylgalactosamine 6-O-2-aminoethylphosphonate in the nervous system of Aplysia kurodai.

A phosphonoglycosphingolipid, named F-21, was found in the nervous system of Aplysia kurodai by two-dimensional thin-layer chromatography (Abe, S., Araki, S., and Satake, M. (1986) Biomed. Res. (Tokyo) 7, 47-51). F-21 was isolated from the nervous tissue of Aplysia in this study, and its chemical structure was characterized as follows, where 2-AEP is 2-aminoethylphosphonate. (Formula; see text) The major aliphatic components of the ceramide portion were palmitic acid (75%), stearic acid (22%), octadeca-4-sphingenine (43%), and anteisononadeca-4-sphingenine (54%). Some information on the steric interactions in the sugar moiety was obtained by NMR spectroscopy. The ring protons of the internal galactose, H1, H3, and H4 and the H3 of the side chain galactose were shifted, as compared to the corresponding protons of dephosphonylated F-21. This may indicate the interactions between the 2-AEP residue of N-acetylgalactosamine and the internal galactose and between the N-acetyl group of N-acetylgalactosamine and the side chain galactose, implying a sterically restricted and unique structure that may relate to some biological functions of F-21.

Acetylgalactosamine↗