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H Ishizuka

Publications and source records attributed to H Ishizuka.

At least 19 recordsLinked to original sources
PubMed1992

Quantitative electron-microscopic analyses of pulpal nerve fibres in the mouse lower incisor after neonatal capsaicin treatment.

A single dose of capsaicin (50 mg/kg) was injected subcutaneously into four mice on day 2 of life; four untreated mice were used as controls. Six months later, a drop of 30 microM capsaicin was instilled on to the cornea of all the mice and the number of times the eyes were wiped was counted to assess the effect of capsaicin on trigeminal sensory neurones. Ultrathin cross-sections were made of the apical pulp of the incisors on both sides of control (n = 8) and capsaicin-treated animals (n = 8). Electron micrographs of pulp nerves were taken and enlarged to a final magnification of x34,000. The numbers of unmyelinated axons in the pulps of all 16 incisors and of unmyelinated axons per Schwann cell in the pulps of four incisors each from the control and capsaicin-treated groups were counted. The short diameters of unmyelinated axons were measured with a computer-operated image analyser. The number of eye wipings was eight-fold less in the capsaicin-treated than in the normal group. This finding clearly indicated that capsaicin irreversibly affected the chemogenic nociceptive trigeminal neurones. The mean number of unmyelinated axons was 345 in controls and 217 (37.1% reduction) in capsaicin-treated animals. The number of unmyelinated axons of less than 0.6 microns dia was 41.5% less in capsaicin-treated mice than in controls. Thus, fine unmyelinated axons in the mouse incisor pulp are capsaicin sensitive, and they are assumed to be nociceptive fibres conveying pain stimuli from the tooth. Capsaicin affected Schwann cells, even those with few unmyelinated axons.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

A putative two-component regulatory system involved in secondary metabolism in Streptomyces spp.

A DNA fragment stimulating actinorhodin, undecylprodigiosin, and A-factor production in Streptomyces lividans 66 was cloned from Streptomyces coelicolor A3(2). Nucleotide sequencing revealed the presence of an open reading frame of 225 codons, named afsQ1, that showed great similarity in amino acid sequence to the response regulators of typical prokaryotic two-component regulatory systems responsible for adaptive responses. The termination codon, TGA, of afsQ1 overlapped the initiation codon, GTG, of a second open reading frame, afsQ2, of 535 codons. The afsQ2 gene product showed homology with the sensory histidine protein kinases of two-component systems. In agreement with the assumption that the AfsQ1 and AfsQ2 proteins comprise an aspartate-histidine phosphotransfer system, an amino acid replacement from Asp to Glu at residue 52 of AfsQ1, generated by site-directed mutagenesis, resulted in loss of the protein's ability to stimulate antibiotic production in S. lividans. Primer extension experiments indicated that transcription of the afsQ1 and afsQ2 genes initiates at the translational start codon (GTG) of the afsQ1 gene. The afsQ1 and afsQ2 genes were physically mapped at a chromosomal position near the actinorhodin biosynthetic gene cluster (act) by hybridization to Southern blots of restriction fragments separated by pulsed-field gel electrophoresis. Disruption of either afsQ1 or afsQ2 on the S. coelicolor chromosome by use of phage phi C31KC515 led to no detectable change in secondary metabolite formation or morphogenesis. The afsQ1 gene on pIJ922 suppressed the S. coelicolor absA mutation and caused actinorhodin production but did not suppress the absB mutation. Southern blot hybridization showed that sequences homologous to afsQ1 and afsQ2 are present in almost all of the actinomycetes examined.

4-Butyrolactone↗
PubMed1992

A light and electron microscopic study on pulpal nerve fibers in the lower incisor of the mouse.

Light and electron microscopic studies were made on pulpal nerve fibers in mouse lower incisors, typical continuously growing teeth. Serial sections, from the apex of the odontogenic sheath to the incisal edge of the apical foramen, were examined by light microscopy to identify myelinated fibers passing through the apical foramen. The fine structure of the pulpal nerves was examined by electron microscopy at three sites: 1) the level at the incisal edge of the apical foramen; 2) a level 5 mm incisal from the apex of the odontogenic sheath; and 3) the level where the incisor comes out of the alveolar bone. No myelinated fibers were found passing through the apical foramen; they were also lacking at the three levels of the pulp. At level 2, unmyelinated axons were seen in close contact with smooth muscle fibers of arterioles. At level 3, nerve fibers were difficult to distinguish from processes of fibroblasts and odontoblasts. Degenerating axons were present in Schwann cells, and fine unmyelinated axons running through the odontoblast cell layer were seen. Various types of unmyelinated axons were observed in the apical region (level 1). These axons were classified into 6 types on the basis of their fine structures: Type I, bundles of unmyelinated axons completely or partly ensheathed by Schwann cell cytoplasm (mature type); Type II, bundles of unmyelinated axons in a space formed by a Schwann cell membrane (regenerating type); Type III, bundles of unmyelinated axons ensheathed not by a Schwann cell, but merely by a basal lamina (regenerating type); Type IV, single axons in direct contact with the basal lamina (regenerating or terminal type); Type V, naked, electron-dense axons with many vesicles and mitochondria (growth cone-like type); and Type VI, electron opaque axons, due to loss of axonal organellae (degenerating type). The significance of these structures is discussed in relation to the continuous growth of the rodent incisor.

Animals↗
PubMed1992

Age-dependent attenuation of the decrease of C fibers by capsaicin and its effects on responses to nociceptive stimuli.

The effects of subcutaneous treatment of mice 10, 15, or 20 days (young) or 30 or 60 days (adult) of age with capsaicin on development of unmyelinated (C) fibers in the L4 dorsal roots were examined. The responses of the mice 2-4 months later to thermal (hot plate; 55 degrees C) and neurogenic plasma extravasative (chemogenic nociception) stimuli were evaluated. Capsaicin treatment 10 days after birth affected development of myelinated fibers significantly (7.9% reduction). Capsaicin treatment 10, 15, 20, and 30 days after birth reduced the number of C fibers 11.0-51.7% and even treatment 60 days after birth caused a significant decrease (10.0%) in the mean number of C fibers. The destruction of C fibers by capsaicin was attenuated during development, but individual differences in the reduction of C fibers were observed on and after 15 days of life and seemed to become more marked over time. Neurogenic plasma extravasation related to primary sensory neurons was decreased by capsaicin, irrespective of the time of treatment. In parallel with reduction of C fibers, hot-plate latency was increased significantly by treatment of young animals with capsaicin. These results suggest that the effect of capsaicin on thermal nociception is age-dependent and is correlated with decrease of C fibers. However, a marked increase in hot-plate latency did not always correspond to a marked decrease of C fibers. In contrast, the reduction of plasma extravasation was not age-dependent: Reduced extravasation of dye persisted during development.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1992

[The significance of the determination of AFP-isoform in the early diagnosis of hepatocellular carcinoma].

To evaluate the significance of the determination of the AFP-isoform in the early diagnosis of hepatocellular carcinoma (HCC), the AFP-isoform was determined in 48 patients with HCC and in 53 patients with liver cirrhosis, using the lectin electrophoresis of AFP by antibody-affinity blotting technique. 1. The HCC-type AFP-isoform was detected in 44 of the 48 patients with HCC, 2. In about 30% of the patients with HCC, the HCC-type AFP-isoform appeared 3-10 months before the graphic diagnosis of HCC, 3. In about 60% of the patients with liver cirrhosis found to have the HCC-type AFP-isoform, HCC developed within one year. Thus, the serial determination of the AFP-isoform in patients with liver cirrhosis was considered very useful for the early diagnosis of HCC.

Carcinoma, Hepatocellular↗
PubMed1991

Cloning, nucleotide sequence, and transcriptional analysis of the NAD(P)-dependent cholesterol dehydrogenase gene from a Nocardia sp. and its hyperexpression in Streptomyces spp.

NAD(P)-dependent cholesterol dehydrogenases [NAD(P)-CDH], which allow easier quantification of cholesterol by means of directly measuring the A340 of NAD(P)H, are useful for clinical purposes. The amino acid sequences of the NH2 terminus and the fragments obtained by CNBr decomposition of the NAD(P)-CDH from a Nocardia sp. were determined for preparation of synthetic oligonucleotides as hybridization probes. A 4.4-kbp BamHI fragment hybridizing to these probes was cloned on pUC19 in Escherichia coli. The nucleotide sequence together with the determined amino acid sequences revealed that this enzyme consists of 364 amino acids (Mr, 39,792) and contains an NAD(P)-binding consensus sequence at its NH2-terminal portion. High-resolution S1 nuclease mapping suggested that in NAD(P)-CDH of both Nocardia and Streptomyces spp. transcription initiates at the adenine residue, which is the first position of the translational initiation triplet (AUG) of this protein. The S1 mapping experiments also showed that cholesterol-dependent regulation in the Nocardia sp. occurred at the level of transcription. In Streptomyces lividans containing the cloned fragment, however, this promoter was expressed constitutively. DNA manipulation of the cloned gene in E. coli, including the generation of a ribosome-binding sequence at an appropriate position by oligonucleotide-directed mutagenesis, led to production of this protein in a very large amount but in the enzymatically inactive form of inclusion bodies. On the other hand, a Streptomyces host-vector system was successfully used for producing 40 times as much enzymatically active NAD(P)-CDH as that produced by the original Nocardia sp.

3-Hydroxysteroid Dehydrogenases↗
PubMed1991

GABAergic neurons in the mouse superficial dorsal horn with special emphasis on their relation to primary afferent central terminals.

Immunocytochemical studies were carried out on the morphological relation between primary afferent central terminals (C-terminals) and GABAergic neurons in the mouse superficial dorsal horn. The superficial dorsal horn is composed of many synaptic glomeruli comprising two types: Type I with centrally located CI-terminals surrounded by several dendrites and few axonal endings, and Type II with centrally located CII-terminals surrounded by several dendrites and a few axonal endings. The CI-terminals are sinuous or scalloped with densely packed agranular synaptic vesicles, a few granular synaptic vesicles and mitochondria, and show an electron dense axoplasm, whereas the CII-terminals are large and round or rectangular with evenly distributed agranular synaptic vesicles, a number of granular synaptic vesicles and mitochondria, and show an electron opaque axoplasm. The immunoreaction of GABA was remarkable in the superficial laminae of the dorsal horn. Many interneuronal somata in the substantia gelatinosa showed GABAergic immunoreactivity. The immunoreaction was seen in the entire GABAergic neuroplasm, but not in the nucleus and its envelope. Most GABAergic features appeared as dendrites making postsynaptic contact with CI- or CII-terminals; i.e., numerous C-terminals made presynaptic contact with GABAergic dendrites. GABA immunoreactivity was seen over round synaptic vesicles and mitochondrial membranes. A few CII-terminals made presynaptic contact with GABAergic interneuronal somata. Previous physiological and anatomical studies have suggested that not only the cutaneous nociceptive primary afferent C-terminals but also mechanoreceptive primary afferent C-terminals make presynaptic contact with the GABAergic dendrites, boutons and soma. The presynaptic relation of these primary afferents with GABAergic neurons seems to provide morphological support for the essential feature of the gate control theory: primary afferent fibers may play a part in the modulation of nociceptive information via GABAergic neurons in the superficial dorsal horn. Small GABAergic terminals were found to make contact with blood capillaries suggesting the release of GABA into circulation.

Animals↗
PubMed1991

Changes in stainability observed by light microscopy in the brains of ataxial mice subjected to three generations of manganese administration.

Two neonates of mice which manifested abnormal motions in their gait in the third generation litter, following the start of manganese (Mn) administration, were selected. One was severely affected by Mn and the other was only moderately affected. Various regions in the brains of the neonates were subjected to histochemical examination under a light microscopy. The losses of stainability in granular cells in the external layer of the cerebral cortex, and Purkinje cells in the cerebellar cortex, and the increase in stainability of the nerve fibers in the cerebellar medulla were in parallel to the degree of abnormal movement in the gait; the greater loss or gain in stainability, varying according to the regions, was associated with the more severe damages to motion. Meanwhile, the changes in the stainabilities of nerve cell nuclei in the lamellar structure of cerebral motor areas and the Nissl bodies in the cerebral medulla were already maximal in the moderately affected neonate. These results indicate that the Mn effect covers a broad area of the extrapyramidal tract even though there are some differences in the sensitivity to Mn in different regions.

Animals↗
PubMed1990

Electron microscopic study of the effect of capsaicin on the mouse chorda tympani nerves.

Studies were made to determine whether this nerve contains capsaicin-sensitive fibres. Capsaicin (50 mg/kg, subcutaneously) was injected into 2 animals on day 2 after birth and into one animal on days 2 and 3 after birth. Both chorda tympani of these and 4 control mice were later excised. The constituent fibres of 3 of the capsaicin-treated and all 8 control nerves were then analysed. The myelinated fibres in 3 chorda tympani of treated and control animals were measured, and the unmyelinated axons in Schwann cells were counted from electron-micrograph montages of the entire nerve. Normal chorda tympani contained about 600 nerve fibres, 55% myelinated and 45% unmyelinated. Capsaicin-treatment did not change the constituent fibres nor the size distribution of the myelinated fibres. Thus no capsaicin-sensitive, nociceptive fibres were found in the mouse chorda tympani. Capsaicin does not destroy the neurones of the geniculate ganglion and parasympathetic, presynaptic fibres. Therefore, gustation and secretion of saliva are not influenced by capsaicin.

Animals↗
PubMed1990

Measurement of cerebral glucose utilization from brain uptake of [14C]2-deoxyglucose and [3H]3-O-methylglucose in the mouse.

Glucose utilization (GU) in the mouse brain in vivo was measured by the simultaneous use of [14C]2-deoxyglucose (2DG), the glucose analogue that can be phosphorylated in the brain, and [3H]3-O-methylglucose (3MG), the nonmetabolizable glucose analogue. Originally, this method was developed by Gjedde et al. (1985) in the rat and in humans. The present study examined the validity of this method in the mouse brain. The effects of urethane and pentobarbital (PB) on GU were also studied. Whereas the distribution volume of 3MG reached a constant value under each condition after 10 min of the tracer circulation, the apparent volume of distribution of 2DG, which increased with time in the awake mice, did not increase so greatly in the anesthetized and hypothermic mice, indicating that the net rate of 2DG phosphorylation is lowered under these conditions. These data were fitted for the conventional three-compartmental model and the values of rate constants of influx (K1), efflux (k2), phosphorylation, and dephosphorylation for 2DG, and K1 and k2 for 3MG were computed by nonlinear least square regression method. No significant difference in the value of K1/k2, the distribution volume of the precursor pool, was observed between 2DG and 3MG, indicating that 3MG can be used to estimate the distribution volume of unmetabolized 2DG in the brain. The values of GU calculated from the values of estimated parameters were not significantly different from those calculated from blood and tissue radioactivities obtained during 10 min after the injection of the tracers in both awake and PB-anesthetized mice. These findings indicate that the double tracer technique is useful for measuring GU in a short duration experiment.

3-O-Methylglucose↗
PubMed1990

The action of capsaicin on primary afferent central terminals in the superficial dorsal horn of newborn mice.

Capsaicin was injected subcutaneously (50 mg/kg) into 10 mice on days 2 or 3 after birth, and 12 h, 3 and 5 days later the distribution and structure of degenerated primary afferent central axons or terminals (C-terminals) in the lumbar spinal dorsal horn were examined by electron microscopy. Degenerated terminal axons with dense or lamellar bodies or higher electron density were conspicuous 12 h after treatment with capsaicin. Severely degenerated unmyelinated axons, including dense or lamellar bodies engulfed by microglial cells, were numerous in the most superficial (marginal) layer, but rarely seen in the substantia gelatinosa. Two types of primary afferent central terminals in the substantia gelatinosa showed various extents of degeneration: small dark C-terminals (CI-terminals) with densely packed agranular synaptic vesicles, and large light ones (CII-terminals) with less dense agranular synaptic vesicles and a few granular synaptic vesicles. Thus, many central axon terminals of dorsal root ganglion (DRG) neurons that are sensitive to capsaicin enter the marginal layer and substantia gelatinosa. Degenerated primary afferent central axons or terminals markedly decreased in the superficial dorsal horn 3 and 5 days after capsaicin treatment, still, there were many degenerating DRG neurons at this time as shown by our previous study. Previously we also reported that fewer slightly degenerating unmyelinated dorsal root axons and small DRG neurons appear at 12 h and larger DRG neurons degenerate later than smaller ones after treatment with capsaicin. As a result, the discovery of many severely degenerated terminal axons in the superficial dorsal horn soon after treatment supports the idea that capsaicin first acts on the central terminals and that this is followed by damage to larger DRG neurons.

Animals↗
PubMed1989

Changes in features of degenerating primary sensory neurons with time after capsaicin treatment.

Capsaicin (50 mg/kg) was injected into new born mice and 5 and 12 h, and 1, 2, 3, and 5 days later, their lumbar dorsal root ganglia (DRG) with the nerve roots were fixed by immersion. The morphological changes which ensued with time after treatment were examined by light and electron microscopy. The findings were as follows: (a) rapid degeneration of certain smaller B-type neurons, indicating their prompt death, was seen 5 h after treatment. Later, accumulated neurofilaments appeared in larger B-type neurons. Fissures of the cytoplasm and cell fragmentation were also observed as particular features of degeneration. Finally, these degenerating neurons, destined to die, appeared as small round figures with a disorganized nucleus. Severely degenerated neurons were seen throughout the survival time after treatment, but seemed to be most numerous after 2-3 days. (b) Three days after treatment the Nissl substances of large A-type neurons appeared dispersed, forming ring-like bundles in the periphery of cells. Cytoplasmic rupture and large membrane-bound spaces with fine granular or fibrillar materials, indicating peripheral cytolysis, were also conspicuous. Some of these cells showed severe degeneration clearly leading to cell death. The A-type neurons began to degenerate later than the B-type neurons. (c) Satellite cells showed an increased amount of electron-opaque cytoplasm that contained large vacuoles and neuronal cell debris. Mitotic figures were increased in satellite cells 3 days after treatment. (d) Unmyelinated axons in the dorsal root of mice treated with capsaicin became enlarged with accumulation of neurofilaments, synaptic vesicles or various kinds of vesicles, multivesicular bodies and mitochondria. Numerous dense lamellar bodies appeared in the unmyelinted axons within DRG 3 days after treatment, but were scarcely seen in the dorsal roots. Degeneration of the myelinated fibers increased with time. Interestingly, capsaicin seemed to have both a direct and indirect action on DRG neurons: its direct action induced rapid degeneration of the smaller neurons, whereas its indirect action induced relatively slow degeneration of the larger neurons, causing chromatolytic changes similar to those induced by periphal nerve axotomy. The injury to DRG neurons due to the indirect action seemed to be induced retrogradely.

Animals↗
PubMed1989

Efficiency of respirator canisters with methyl bromide.

Two kinds of respirator canisters, an organic vapor (OV) canister containing activated carbon and a methyl bromide (MB) canister containing activated carbon impregnated with triethylenediamine were investigated for their filtration efficiency of MB gas under various conditions of MB concentration, humidity and temperature. At lower MB concentrations, the breakthrough time of the OV canister was shorter than that of the MB canister. It also decreased with an increase in temperature, whereas the breakthrough time of the MB canister did not change with temperature. Humidity affected the breakthrough times of the OV canister as much as those of the MB canister. The desorption and the remaining filtration efficiency of MB gas were examined in both canisters which had been used for fumigation in plant quarantine. More than 5 ppm of MB gas leaked from 11 out of 18 used OV canisters, whereas less than 0.1 ppm MB leaked out from each of the used MB canisters. The mean remaining breakthrough time of the used OV canisters was 9.3 min, whereas that of the used MB canisters was 74.4 min. From the present study, it was shown that the gas masks with the OV canisters were not suitable for fumigating with MB gas.

Evaluation Studies as Topic↗
PubMed1989

Nonlinear relationship between benzodiazepine receptor occupancy and glucose metabolic response in the conscious mouse brain in vivo.

To evaluate the relationship between the pharmacological effect of benzodiazepine (BZP) and BZP receptor (BZP-R) binding in the conscious mouse brain, a response of the local cerebral metabolic rate of glucose utilization (GU) to clonazepam (CNZ) was measured as an index for the pharmacological effect. Two glucose analogs (3-O-[3H]methylglucose and 2-[14C]deoxyglucose) method, originally presented by A. Gjedde was used for determination of GU. In the cerebral cortex, GU decreased to 70 to 80% at 60 min after i.v. administration of CNZ (0.005-1.0 mg/kg), but CNZ did not change the lumped constant, and this effect was diminished completely by the administration of a BZP antagonist, Ro-15-1788 (5 mg/kg). The maximum effect of CNZ on GU (about 30% decrease) was found at 0.1 mg/kg of CNZ, but increasing the dose to 1 mg/kg had very little additional effect. In vivo BZP-R occupancy was measured using [3H]-Ro-15-1788. Receptor occupancy increased from less than 10% at a dose of 0.005 mg/kg up to essentially 100% at doses of 1 mg/kg or greater. ID50 in dose-response curve of the receptor occupancy for CNZ and ED50 in that of decrease in GU were 0.3 and 0.007 mg/kg, respectively . A nonlinear and hyperbolic relationship was observed between the receptor occupancy and the response for the glucose metabolic rate, indicating that BZP exert the maximum glucose metabolic change at a low fractional receptor occupancy (30-40%).

Animals↗
PubMed1989

[Preventive effect of urinastatin on cisplatin-induced nephrotoxicity].

Anticancer chemotherapy with cisplatin (CDD) as the main drug (combined with adriamycin (ADM) and cyclophosphamide (CPM), PAC therapy) was performed on patients with ovarian cancer. Urinastatin (US) was concurrently administered to assess its effectiveness in preventing CDDP-induced nephrotoxicity. Twenty-two patients with gynecological malignant tumor were treated with PAC therapy, and of these, twelve concurrently received US. The ten who did not receive US served as the control. As a rule, one course of PAC therapy consisted of 50mg/m2 CDDP, 50mg/m2 ADM and 500mg/m2 CPM. Before the administration of CDDP, US 100,000 units was administered by I.V. drip infusion and after the administration, US 400,000 units was again administered by I.V. drip infusion at a speed of 100,000 to 200,000 units/hour. A total of approximately 3,500ml of fluids was administered I.V.. Each course of PAC therapy took 7 to 14 hours to complete. The control group underwent PAC therapy in a regimen not including US. As indexes of nephrotoxicity, serum levels of BUN, creatinine (Cr), and creatinine clearance (Ccr), and N-acetyl-beta-glucosaminidase (NAG), gamma-glutamyl transpeptidase (gamma-GTP), and arylamidase (AA) activity in the urine was determined before treatment and at days 1, 2, 3, 7, 14, and 21 after the initiation of PAC therapy. Changes in serum BUN, Cr, and Ccr levels after CDDP administration in the group with and the group without concurrent US were similar. Urinary gamma-GTP, AA, and NAG activity remained unchanged after CDDP administration in the group with concurrent US. In contrast, in the group without US, this urinary enzyme activity was transiently increased after CDDP administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Early diagnosis of hepatocellular carcinoma with lectin electrophoresis of serum alpha-fetoprotein.

A sensitive procedure involving lectin affinity electrophoresis of alpha-fetoprotein (AFP) was established. AFPs electrophoresed on lectin-containing gels were blotted on nitrocellulose membrane which was precoated with the specific antibody to AFP and stained with peroxidase-labeled anti-AFP antibody. This method could detect as little as 4 micrograms/l of purified AFP dissolved in buffer, or 50 micrograms/l in serum specimens. A number of patients with liver disease have been followed for long periods in Nihon University Hospital, Tokyo. Serum specimens were collected serially and stored frozen. We have reinvestigated retrospectively 6 series of serum specimens by the lectin-immunoblotting technique and found 3 cases that revealed a hepatocellular carcinoma-specific AFP variant at a very early stage, in advance of any other evidence of hepatocellular carcinoma by clinical examination.

Carcinoma, Hepatocellular↗