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Biomedical subjects

H Ichikawa

Publications and source records attributed to H Ichikawa.

At least 361 records · Page 20Linked to original sources
PubMed1990

Influence of colchicine on the addition of a sugar to the enamel protein in secretory ameloblasts of cultured germs of rat molar tooth by 3H-galactose radioautography.

The influence of colchicine on the addition of 3H-galactose to the enamel protein in secretory ameloblasts of cultured germs of rat molar tooth was investigated by light- and electron-microscopic radioautography. In tooth germs cultured without colchicine, the reaction products of 3H-galactose were observed over Golgi cisternae at early chase times and then localized over the enamel with time. In tooth germs cultured with colchicine, the silver grains were seen over the Golgi cisternae, condensing granules and accumulated secretory granules. Some grains also appeared with time over the pale granular material precipitated in the intercellular space with colchicine treatment. In quantitative analysis with light microscopic radioautography, values of silver grain counts over the unit area (100 microns2) on ameloblasts and enamel of colchicine-treated tooth germs were significantly lower at both 0 min and 30 min chase after 30 min pulse than those of control tooth germs, respectively. This finding indicates that colchicine diminished the incorporation of 3H-galactose into the secretory ameloblast of cultured tooth germs. It is suggested that colchicine decreases the activity of the Golgi apparatus with regard to the addition of sugar to the synthesizing glycoprotein in the secretory ameloblast.

Ameloblasts↗
PubMed1990

Leucine-enkephalin-, neurokinin A- and cholecystokinin-like immunoreactivities in the guinea pig tongue.

The occurrence of these neuropeptides was examined by immunofluorescence. Leu-Enk-like immunoreactivity was seen in nerve fibres associated with the epithelium, blood vessels and lingual salivary glands as well as in ganglionic cells within the tongue. Neuropeptide A-like immunoreactivity was found in nerve fibres associated with the epithelium, taste buds, blood vessels and lingual salivary glands. Cholecystokinin-like immunoreactivity was found in some nerve fibres around blood vessels as well as in ganglionic cells. The coexistence of these neuropeptides and substance P was also demonstrated in some nerve fibres and ganglionic cells within the tongue. Like substance P, these neuropeptides could be involved in blood flow regulation, salivation and as trophic factors for taste buds.

Animals↗
PubMed1990

Fine structure of calcitonin gene-related peptide-immunoreactive nerve fibres in the rat temporomandibular joint.

The distribution and fine structure of these nerve fibres was examined by immunoelectron microscopy. CGRP-immunoreactive fibres were seen in the nerve bundles, blood vessels and periosteum around the condyle as well as in the disc. These nerve fibres were unmyelinated and had diameters varying from 200 to 600 nm. They were completely or partially enclosed by Schwann cell cytoplasm and did not form synaptic contact with any cells. CGRP-immunoreactive nerve fibres may be sensory nature and this peptide could be involved in pain transmission and neurogenic inflammation.

Animals↗
PubMed1990

The distribution of vasoactive intestinal polypeptides and calcitonin gene-related peptide in the periodontal ligament of mouse molar teeth.

The distribution of VIP- and CGRP-containing nerve fibres was examined by indirect immunofluorescence. There were many such fibres in the lower third of the ligament, some around the blood vessel close to the socket wall. In the middle third of the ligament, some CGRP-containing fibers entered from the lateral wall of the socket; this type of fibre was more numerous in the lower third than in middle third. There were some VIP-containing fibres but no CGRP-containing fibres in the ligament surrounding the furcation of the molar roots.

Alveolar Process↗
PubMed1990

Hemorrhagic toxicity of d-alpha-tocopherol in the rat.

When male Sprague-Dawley rats were administered d-alpha-tocopherol and butylated hydroxytoluene in the diet or intraperitoneally for 7 days, prolongations of prothrombin time and partial thromboplastin time were observed in those given both chemicals by both routes in a dose-dependent manner. However, intraperitoneal d-alpha-tocopherol was less toxic and the prothrombin and partial thromboplastin time indices were approx. 70% and approx. 60% in rats given 2.91 mmol/kg body weight daily. Rats given d-alpha-tocopherol in the diet at a daily dose of 2.31 mmol/kg body weight were approx. 13% and approx. 16% of the control, and in those dietary groups severe hemorrhages in epididymis and other organs were also observed. Plasma concentrations of total tocopherols were more increased by the dietary than the intraperitoneal route. These results suggest that the great difference in the hemorrhagic effect of d-alpha-tocopherol between dietary and intraperitoneal route administration may largely be due to the differing absorption rates of the drug by these two means.

Administration, Oral↗
PubMed1990

Neural networks applied to quantitative structure-activity relationship analysis.

An application of the neural network to quantitative structure-activity relationship (QSAR) analysis has been studied. The new method was compared with the linear multiregression analysis in various ways. It was found that the neural network can be a potential tool in the routine work of QSAR analysis. The mathematical relationship of operation between the neural network and the multiregression analysis was described. It was shown that the neural network can exceed the level of the linear multiregression analysis.

Animals↗
PubMed1990

[The optimal oxygenation of cardioplegic solution--the buffer effect of carbon dioxide and pH control].

A series of studies was undertaken to establish the optimal oxygenation of St. Thomas' Hospital cardioplegic solution (ST). Using an isolated working rat heart model of cardiopulmonary bypass and the cardioplegic arrest the effect of oxygenation of ST were investigated in this study. The effects of oxygenated ST with various O2/CO2 mixture (100% O2, 99% O2 + 1% CO2, 98% O2 + 2% CO2, 95% O2 + 5% CO2) upon post ischemic functional recovery were compared with those of non-oxygenated ST. Under both normothermic and hypothermic conditions, the pH of the St. Thomas' gassed with 99% O2 + 1% CO2 mixture was maintained at 7.8, and this cardioplegic solution showed highest percent recovery of aortic flow. On the contrary, the pH of St. Thomas' cardioplegic solution oxygenated with 100% O2 exceed 9.0 and it showed lethal effect upon postischemic cardiac function. Thus oxygenation of NaHCO3 containing crystalloid cardioplegic solution oxygenated with 100% O2 is rather harmful and the 99% O2 + 1% CO2 gas is the crucial gas mixture for clinical and experimental use with oxygenated ST.

Animals↗
PubMed1990

[A study of communication and behavior management in pediatric dentistry. Approach to the child using the fairy tales].

There were a total of 100 subjects, of which 50 were children and 50 were mothers. The first time, the doctor lends the child the fairy tale book. The second time, the child is treated under the audio-analgesia with the same fairy tale book and the child borrows on other fairy tale book. The third time, the child is also treated under the audio-analgesia. The child, the mother and the doctor answered the questionnaires. Changes in internal behavior were observed by polygraph system. The subjects comprised a total 13 children (4 to 6 years), of which 6 were males and 7 were females. The first time, the emotional reactions were observed when the subjects were stimulated by the engine, the turbine and the crying for 10 seconds each. The Second and third time, the emotional reactions were also observed under the audio-analgesia. The change ratios were analyzed with respect to Plethysmogram, Respiration Curve and Galvanic Skin Reflex. The results are summarized as follows: 1. 91.8% of the parents answered "I would like my children to be treated under the audio-analgesia using fairy tales." 2. 73.5% (2nd time) and 80% (3rd time) of the children answered "The treatment has been pleasant." 3. 61.2% (2nd time) and 64% (3rd time) of the doctors answered "The anxiety and fear was reduced by the approach." 4. With the engine stimulation, the emotional reaction decreased in the order, of the 1st time greater than 3rd time greater than 2nd time. There were significant differences between the 1st time and the 2nd time, and also between the 1st time and the 3rd time.(ABSTRACT TRUNCATED AT 250 WORDS)

Audioanalgesia↗
PubMed1990

[Role of active oxygen species and lipid peroxidation in liver injury induced by ischemia-reperfusion].

The role of superoxide and lipid peroxidation in liver injury induced by ischemia-reperfusion was investigated in rats. Ischemic condition of the liver was created by applying small clamps to the right branch of portal vein and the right hepatic artery for 15 min. Clamping of hepatic artery and portal vein could decrease the hepatic blood flow to about 30% of that measured before the clamping. Levels of serum GPT and thiobarbituric acid (TBA) reactive substances in the liver tissue were significantly increased 30 min after the reperfusion following 15 min of ischemia. The increase in serum GPT and TBA reactants in the liver tissue was significantly inhibited by the treatment with superoxide dismutase combined with catalase. The treatment with allopurinol significantly inhibited the elevation of serum GPT levels and showed a tendency to inhibit the increase in TBA reactants in liver tissue. These results suggest that active oxygen species and lipid peroxidation may play an important role in the pathogenesis of ischemia-reperfusion injury in the liver, and hypoxanthine-xanthine oxidase system may be one of the main sources of active oxygen species.

Animals↗
PubMed1990

[Role of oxygen-derived free radicals for antitumor effects of intra-arterial injection with adriamycin].

This study examined the role of oxygen-derived free radicals for antitumor effects of intra-arterial injection with adriamycin (ADR). The effect of chemoembolization using ADR and degradable starch microspheres (DSM) was studied in rabbits with VX2 carcinoma of the hind leg. The tumor growth in rabbit treated with chemoembolization (ADR: 3.0 mg/kg + DSM 20mg/kg) was completely suppressed, but the therapeutic effect of chemoembolization combined with dimethylsulfoxide (DMSO) was reduced. On the other hand, the therapeutic effect of chemoembolization combined with superoxide dismutase and catalase was not reduced. These results indicate that the production of oxygen-derived free radicals, especially hydroxyl radical in the cancer cell, plays an important role in the antitumor effect of adriamycin.

Animals↗
PubMed1989

Carbonic anhydrase activity in the trigeminal primary afferent neuronal cell bodies with peripheral axons innervating the mandibular molar tooth pulps of the rat.

Trigeminal primary afferent neuronal cell bodies were labeled with FITC-WGA retrogradely transported from the mandibular molar tooth pulp (tooth pulp) and the cutaneous branch of the mylohyoid nerve (cutaneous nerve) in the rat. Tissue sections were then incubated in Hansson's medium for histological demonstration of carbonic anhydrase (CA) activity. About 85% of primary neurons innervating the tooth pulp had medium to large cell bodies (greater than or equal to 300 microns 2 in cross-sectional area), while 77% of those innervating the cutaneous nerve were small (less than 300 microns 2). A total of 32% of the tooth pulp cells exhibited CA activity. CA-containing cells constituted only about 4% of the cutaneous nerve cells. In view of the known distribution of CA within the rodent nervous system, the CA-containing cells are considered to represent the tooth pulp primaries conducting in A-beta velocity range and projecting to rostral subdivisions of the brainstem sensory trigeminal nuclear complex.

Afferent Pathways↗
PubMed1989

[Antitumor effect and indication of chemoembolization using degradable starch microspheres and regional hyperthermia in patients with hepatocellular carcinoma].

Antitumor effects and indications of chemoembolization using degradable starch microspheres (DSM) and regional hyperthermia were investigated in patients with unresectable hepatocellular carcinoma. Chemoembolization using DSM was performed in 40 cases and fourteen cases were treated with the combination of hyperthermia. Tumor regression rate over 50% was 48% (chemoembolization alone: 42%, combined hyperthermia: 57%). Though one and two year survival rates were 62% and 54% respectively in the treatment with chemoembolization alone, one year survival rate was 91% in the treatment with combined hyperthermia. From the viewpoint of antitumor effect, it was thought that effectual indications of chemoembolization using DSM alone were the cases whose tumor size were below 7 cm and portal invasion were negative. These indications however were spread by the combination of hyperthermia. The DSM, temporary embolus, is suitable for combination of hyperthermia because chemoembolization using DSM can be performed many times. The cases with clinical stage III and obstruction of the first branch of portal veins did not become severe hepatic failure because DSM was temporary embolus. Therefore, from the viewpoint of safety, chemoembolization using DSM has almost the same indications as intra-arterial infusion therapy. These results suggested that chemoembolization using DSM will be a beneficial methods as combination therapy for unresectable hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed1989

Peptidergic innervation of the temporomandibular disk in the rat.

The peptidergic innervation of the temporomandibular disk was investigated in the postnatal young rat by using an indirect immunofluorescence method. Calcitonin gene-related peptide-containing nerve fibers were located around the blood vessels and terminated as free nerve endings in the disk. These nerve fibers may be of a sensory nature.

Aging↗
PubMed1989

Localization of two distinct acid phosphatases in secretory ameloblasts of rat molar tooth germs.

Acid phosphatases were examined histochemically at the light- and electron-microscopic levels using para-nitrophenyl phosphate (pNPP) and beta-glycerophosphate (beta-GP) as substrates. By light microscopy, there was intense activity with pNPP in supranuclear and distal regions of the secretory ameloblast, and moderate or slight activity respectively in those regions with beta-GP. These enzyme activities were less at the late secretory stage of amelogenesis and disappeared at the transitional stage. By electron microscopy, acid phosphatase activity was seen in the trans side cisternae of the Golgi apparatus, in lysosome-like granules, and in small vesicles in the Tomes' processes. The activity with pNPP but not beta-GP was also localized at the plasma membrane (proximal, lateral and distal surface). Activity with beta-GP was completely inhibited by 1 mM sodium tartrate and by 1 mM NaF; activity with pNPP was inhibited by 1 mM NaF and 10 mM sodium tartrate, but not by 1 mM sodium tartrate. Thus there are at least two different acid phosphatases, one tartrate-sensitive and the other 1 mM tartrate-resistant, in the secretory ameloblast; the tartrate-resistant enzyme is plasma-membrane bound.

Acid Phosphatase↗
PubMed1989

Mongolian spots associated with cleft lip.

Of the present series comprising 66 newborns with cleft lip, 13 (20%) had pigmented macules in the labial skin on the lateral side of the cleft. Histological examination using serial sections were performed on 47 cases and showed evidence of dermal melanocytosis in 40 cases (85%) consisting of 33 (70%) without clinically detectable macules and 7 (15%) with obvious pigmented macules. The fusiform cells in the dermis were positive for dopa reaction and anti-melanocyte antibody. The high incidence of dermal melanocytosis is comparable to that of common Mongolian spots in Asian babies.

Cleft Lip↗
PubMed1989

Delayed cutaneous metastasis of gastric carcinoma.

This paper describes a case of skin cancer resembling carcinoma en cuirasse associated with multiple bone lesions, which were both judged to be due to metastasis of poorly differentiated carcinoma of the stomach, the primary lesion excised ten years previously. Overt bone involvement had been observed for more than two years and a half. Histologic examination of a skin biopsy specimen showed that carcinoma cells had infiltrated into the middle and lower dermis, forming clusters and strands in an abundance of fibrous stromata. No primary lesion was detected in the remnant stomach at autopsy.

Adenocarcinoma↗