Biomedical subjects

Y Endo

Publications and source records attributed to Y Endo.

At least 217 records · Page 12Linked to original sources

PubMed1998

Allele-specific inactivation of the alpha4 integrin gene expression in fibrosarcoma cell lines and relevance for spontaneous metastasis.

Deregulated expression of genes is found in cancer cells, which may affect malignant properties, but it is unclear whether such modulation occurs allele-specifically. This study shows that the gene coding alpha4 integrin, a cell adhesion molecule, underwent allelic inactivation in a series of heterozygous murine fibrosarcoma cell lines (MST lines) with different metastatic potentials. P4 cells expressed the alpha4 integrin gene from one allele at a level comparable to that of the primary MST1 tumor, whereas the descendent lines of P4 exhibited decreased expression of both alleles. No allelic loss of DNA was observed in these cells. Other four clones derived from P4 and five clones from a different tumor also showed such two-step inactivation. Intriguingly, the loss of expression was correlated with the acquisition of spontaneous, but not artificial, metastatic ability. This is consistent with the previous result of inverse relation between the expression of alpha4/beta1 integrin and the invasive potential of B16 melanoma cells. Analysis of DNA methylation and chromatin state of the alpha4 integrin gene failed to provide a clue to difference between the two alleles in the cell lines. These results suggest that the allelic inactivation is a process giving loss of function to one allele, although the mechanism is unclear.

Alleles↗

PubMed1998

cDNA cloning of a new low-density lipoprotein receptor-related protein and mapping of its gene (LRP3) to chromosome bands 19q12-q13. 2.

We report herein the cDNA cloning of a novel member of the low-density lipoprotein receptor (LDLR) family termed LDLR-related protein 3 (LRP3). Human and rat LRP3 cDNAs encode a 770-amino-acid type 1 membrane protein with the following regions: a putative signal sequence, two isoleucine/leucine/valine-rich regions with an RGD sequence, two ligand-binding repeat regions, a putative transmembrane region, and a proline-rich cytoplasmic region with a tyrosine-based internalization signal. Fluorescence in situ hybridization of human chromosomes revealed that the human LRP3 gene mapped to chromosome bands 19q12-q13.2. LRP3 transcript was detected in a wide range of human tissues, with the highest expression in skeletal muscle and ovary. Despite the presence of the ligand-binding repeats, CHO cells transfected with LRP3 did not bind beta-migrating very-low-density lipoprotein or receptor-associated protein.

Amino Acid Sequence↗

PubMed1998

Induction of histidine decarboxylase in skeletal muscle in mice by electrical stimulation, prolonged walking and interleukin-1.

1. In normal non-exercised skeletal muscles in mice, the activity of histidine decarboxylase (HDC), the enzyme which forms histamine, was very low. 2. HDC activity in the quadriceps femoris muscle was markedly elevated following contractions evoked by even a few minutes of direct electrical stimulation, peaking at 8-12 h following contraction lasting 10 min, and gradually decreasing during the 24 h following contraction. The elevation in HDC activity depended on the duration and strength of stimulation. 3. Direct electrical stimulation induced a quantitatively similar elevation of HDC activity in the muscles of mast-cell-deficient mice (W/Wv mice). 4. Prolonged walking at a speed of 6 m min-1 for up to 6 h with a 30 min rest period at 3 h also elevated muscle HDC activity, the magnitude of the elevation being related to the duration of the walking. Repeated exercise (training) for several days diminished the elevation of muscle HDC activity induced by walking. In contrast, starvation augmented the elevation of muscle HDC activity induced by walking. 5. Intraperitoneal injection of interleukin-1beta (IL-1beta) also elevated muscle HDC activity in a dose-dependent manner, as little as 1 microg kg-1 of IL-1 producing a significant elevation of muscle HDC activity. 6. IL-1beta was immunohistochemically detected in normal non-exercised quadriceps femoris muscle. We could not detect a significant increase in IL-1beta after exercise in the muscle or in serum: it may be below the level of detection. 7. On the basis of these results, together with those reported previously and the known actions of histamine, we propose that an elevation of HDC activity and generation of histamine occur in skeletal muscle following muscle contraction possibly as a result of induction by IL-1beta and that the histamine may be involved in fatigue in skeletal muscle as part of a defence mechanism preventing damage to the muscle.

Animals↗

PubMed1998

The relation between the growth patterns of gastric carcinoma and the expression of hepatocyte growth factor receptor (c-met), autocrine motility factor receptor, and urokinase-type plasminogen activator receptor.

BACKGROUND: Hepatocyte growth factor receptor (c-met), autocrine motility factor receptor (AMFR), and urokinase-type plasminogen activator receptor (uPAR) are known to play important roles in tumor cell migration, invasion, and metastasis. The authors studied the relation between the expression patterns of these genes and the growth patterns of human gastric carcinoma. METHODS: The relation between the expression of c-met, AMFR, and uPAR and clinicopathologic parameters was studied using immunohistochemical preparations from 102 paraffin embedded primary gastric carcinomas. RESULTS: Of 102 cases, 43 (42%) had overexpression of c-met, and AMFR and uPAR immunoreactivity was observed in 41 cases (40%) and 38 cases (37%), respectively. Macroscopic examination revealed that all three genes were expressed in 1 (3%) of 32 early stage gastric carcinomas, 0 (0%) of 29 localized carcinomas (Borrmann types 1 and 2), and 16 (39%) of 41 infiltrating carcinomas (Borrmann types 3 and 4). In particular, the incidence (68%, 13 of 19 cases) of simultaneous expression of the three genes was significantly higher in Borrmann type 4 gastric carcinoma than in the other macroscopic types (P < 0.01). The overexpression of these genes was also closely associated with lymph node metastasis and peritoneal dissemination. In addition, the simultaneous overexpression of the three genes was associated with positive lymphatic vessel invasion and infiltrating type. Patients with tumors that simultaneously expressed all three genes had significantly poorer prognoses than those with tumors expressing only one or two of the genes. Furthermore, the number of genes expressed was closely related to the prognosis, and the Cox proportional hazards model identified this as one of the independent prognostic factors. CONCLUSIONS: These results suggest that the expression patterns of c-met, AMFR, and uPAR may be closely associated with the progression and invasion of gastric carcinoma as well as the prognoses of the patients. Borrmann type 4 gastric carcinoma is characterized by the diverse and simultaneous expression of these three genes.

Adult↗

PubMed1998

Clarification of the binding mode of teleocidin and benzolactams to the Cys2 domain of protein kinase Cdelta by synthesis of hydrophobically modified, teleocidin-mimicking benzolactams and computational docking simulation.

Phorbol esters (12-O-tetradecanoylphorbol 13-acetate; TPA) and teleocidins are known to be potent tumor promoters and to activate protein kinase C (PKC) by binding competitively to the enzyme. The relationship between the chemical structures and the activities of these compounds has attracted much attention because of the marked structural dissimilarities. The benzolactam 5, with an eight-membered lactam ring and benzene ring instead of the nine-membered lactam ring and indole ring of teleocidins, reproduces the active ring conformation and biological activities of teleocidins. Herein we describe the synthesis of benzolactams with hydrophobic substituents at various positions. Structure-activity data indicate that the existence of a hydrophobic region between C-2 and C-9 and the steric factor at C-8 play critical roles in the appearance of biological activities. We also computationally simulated the docking of teleocidin and the modified benzolactam molecules to the Cys2 domain structure observed in the crystalline complex of PKCdelta with phorbol 13-acetate. Teleocidin and benzolactams fitted well into the same cavity as phorbol 13-acetate. Of the three functional groups hydrogen-bonding to the protein, two hydrogen-bonded with protein atoms in common with phorbol 13-acetate, but the third one hydrogen-bonded with a different protein atom from that in the case of phorbol 13-acetate. The model explains well the remarkable difference in activity between 5 and its analogue having a bulky substituent at C-8.

Binding Sites↗

PubMed1998

Difference in chromatin packaging between active and inactive X chromosomes by fractionation and allele-specific detection.

Using a novel method consisting of chromatin fractionation and allele-specific detection, chromatin packaging is compared between active X (Xa) and inactive X (Xi) chromosomes for five tumor cell clones that were derived from inter-subspecific F1 female mice. Separation of heterochromatic (H) and euchromatic (E) fractions is monitored by hybridization with subtelomeric satellite DNA and ribosomal RNA gene and by PCR amplification of p53 gene/pseudogene with one primer set. The H fraction was enriched with satellite and p53 pseudogene probably existing in heterochromatic regions while the E fraction showed inverse, suggesting fair separation. Analysis with seven marker and three gene loci revealed concentration of alleles on Xi in the H fraction and those on Xa in the E fraction, though the concentration levels varied. This implies that the packaging level of Xi is higher than that of active or inactive euchromatin on Xa. Intriguingly, one cell line showed biallelic expression and chromatin relaxation of the Pgk-1 locus, suggesting that the relaxation occur regionally on X chromosome.

Alleles↗

PubMed1998

Development and biochemical characterization of a 2'-C-cyano-2'-deoxy-1-beta-D-arabino-pentofuranosylcytosine (CNDAC)-resistant variant of the human fibrosarcoma cell line HT-1080.

2'-C-Cyano-2'-deoxy-1-beta-D-arabino-pentofuranosylcytosine (CNDAC) is an antitumor nucleoside with a novel chemical structure that exerts potent antitumor activity against various human tumor cells in vitro and in vivo. In order to be active it needs to be phosphorylated by deoxycytidine (dCyd) kinase. We induced resistance to CNDAC in the human fibrosarcoma cell line HT-1080 by exposure to increasing concentrations of CNDAC. The resistant cells showed over 560 times higher resistance as compared to that of the parental HT-1080 cells and were cross-resistant to the other 2'-deoxycytidine derivatives. The dCyd kinase mRNA expression of the resistant cells decreased and there was the expression of aberrant mRNA of dCyd kinase which contained a 116-nucleotide deletion within the coding region, corresponding to the fifth exon of the gene. The dCyd kinase enzymatic activity of the resistant cells was deficient. The initial uptake of CNDAC into the resistant cells was similar to that of the parental cells. However, the incorporation of CNDAC into the DNA fraction of the resistant cells was significantly less than that of the parent cells. These results led us to conclude that the acquired resistance to CNDAC can be attributed to a deficiency of dCyd kinase activity, which should be based on a remarkable decrease in mRNA expression and genetic mutation of the dCyd kinase gene, but not on cellular CNDAC accumulation.

Antimetabolites, Antineoplastic↗

PubMed1998

A novel point mutation in an acceptor splice site of intron 32 (IVS32 A-12-->G) but no exon 3 mutations in the glycogen debranching enzyme gene in a homozygous patient with glycogen storage disease type IIIb.

Genetic deficiency of the glycogen-debranching enzyme (debrancher) causes glycogen storage disease type III (GSD III), which is divided into two subtypes: IIIa and IIIb. In GSD IIIb, glycogen accumulates only in the liver, whereas both liver and muscles are involved in GSD IIIa. The molecular basis for the differences between the two subtypes has not been fully elucidated. Recently, mutations in exon 3 of the debrancher gene were reported to be specifically associated with GSD IIIb. However, we describe a homozygous GSD IIIb patient without mutations in exon 3. Analysis of the patient's debrancher cDNA revealed an 11-bp insertion in the normal sequence. An A to G transition at position -12 upstream of the 3' splice site of intron 32 (IVS 32 A-12-->G) was identified in the patient's debrancher gene. No mutations were found in exon 3. Mutational analysis of the family showed the patient to be homozygous for this novel mutation as well as three polymorphic markers. Furthermore, the mother was heterozygous and the parents were first cousins. The acceptor splice site mutation created a new 3' splice site and resulted in insertion of an 11-bp intron sequence between exon 32 and exon 33 in the patient's debrancher mRNA. The predicted mutant enzyme was truncated by 112 amino acids as a result of premature termination. These findings suggested that a novel IVS 32 A-12-->G mutation caused GSD IIIb in this patient.

Adolescent↗

PubMed1998

Effects of a urinary trypsin inhibitor on acute circulatory insufficiency after surgical operation.

OBJECTIVE: To assess the effectiveness of an urinary trypsin inhibitor (UTI) on a surgical stress, particularly the influences on cytokines and diuretic hormones. SUBJECTS AND METHODS: Sixteen patients with carcinoma of the digestive system and predicted to suffer from circulatory insufficiency were enrolled. Selection of group was divided alternatively. UTI was administered for 5 consecutive days, at a dose of 300,000 units per day. Urine and blood specimens were collected before, immediately after, and 1, 3, and 5 days after surgery. Interleukin 8 (IL-8), polymorphonuclear leukocyte elastase (PMNE), vasopressin (ADH), atrial natriuretic peptide (ANP), angiotensin II (AT-II), and endothelin 1 (ET-1) in the blood, and N-acetyl-D-glucosaminidase (NAG) in the urine, were determined. RESULTS: A UTI group was 9 patients, and a control group was 7 patients. The operation time was significantly longer in the UTI group than in the control group. In the UTI group, the elevation of IL-8, PMNE/WBC, ADH, urinary NAG, and BUN were significantly inhibited. AT-II and ET-1, in the UTI group, tended to be suppressed, and ANP showed the similar changes in the two groups. CONCLUSION: UTI is considered effective in the prevention of excessive reaction against major surgery.

Angiotensin II↗

PubMed1998

Mechanism of parasitism-induced elevation of haemolymph growth-blocking peptide levels in host insect larvae (Pseudaletia separata).

Growth-blocking peptide (GBP) has been purified for the first time from the haemolymph of the host armyworm Pseudaletia separata whose growth is inhibited and shows developmental arrest in the last larval instar stage when parasitized by the parasitoid wasp Cotesia kariyai. GBP naturally occurs in the haemolymph of lepidopteran larvae but its concentration is very low during the last larval instar in comparison with that in the penultimate larval instar. However, by 24h after parasitization or polydnavirus (PdV)-infection on day 0 of the last larval instar, a four-fold increase in GBP level, compared with synchronous non-parasitized control larvae, is observed. Although Northern blot analysis indicates that GBP mRNA is transcribed in brain-nerve cord and fat body, plasma GBP is likely to be secreted mainly from fat body because the GBP mRNA level is approximately 100-fold higher in fat body than that in brain-nerve cord. RT-PCR analysis demonstrates the constant expression of GBP mRNA in both parasitized (or PdV-infected) and non-parasitized larval fat body, which suggests that parasitism does not influence transcriptional level, but might influence post-transcriptional level to elevate plasma GBP concentration. This interpretation was supported by estimating GBP precursor levels in fat body of PdV-infected and non-infected larvae. Virus infection appears to elevate the GBP precursor levels in fat body to about six times greater than that in non-infected last instar larvae by 6h after PdV-injection. The GBP processing enzyme activity that occurs in Golgi body-rich extract of the fat body is increased by about 90% after parasitization or PdV-injection.

Journal Article↗

PubMed1998

B-cell lymphoma of mucosa-associated lymphoid tissue of the thymus: a report of two cases with a background of Sjögren's syndrome and monoclonal gammopathy.

Two rare cases of low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) arising in the thymus are reported. Both patients (a 61-year-old man and a 75-year-old woman) were suffering from Sjögren's syndrome and immunoglobulin (Ig)A kappa monoclonal gammopathy. Mixed IgA-IgG cryoglobulinemia was also present in the male case. Tumor cells expressed IgA and kappa antibody reactive proteins identical with serum IgA kappa M. Moreover, we could demonstrate rearrangements of the immunoglobulin heavy and light chain genes, which supported the monoclonal origin of tumor cells. Immunological abnormalities improved after thymectomy in one case in which the tumor cells were confined to the thymus, but not the other with regional lymph node involvement, suggesting a causal role for the tumor. MALT lymphomas of the thymus thus appear to be associated with immunological disorders such as Sjögren's syndrome or monoclonal gammopathy.

Aged↗

PubMed1998

Clinicopathological and immunological characteristics of six cats with granular lymphocyte tumors.

Clinical and immunological characteristics were investigated in six cases of feline granular lymphocyte (GL) tumor. The ages of the affected cats were relatively old, ranging from 4 to 13 years of age. Gastrointestinal signs were commonly observed in these cases. Only one of the six GL tumor cases was positive for feline leukemia virus (FeLV) antigen. Phenotypic analysis revealed that the GL tumor cells from all of the six cases lacked the T- or B-cell markers. These GL tumor cells were examined by Southern blot analysis using feline immunoglobulin (Ig) and T-cell receptor (TCR) gene probes. GL tumor cells obtained from two cases were identified as cells of T-cell lineage by the presence of a rearranged TCR beta gene, whereas those from the other four cases were considered to be derived from non-T- non-B-cell lineage because of the absence of rearrangement of these genes. These findings indicated that feline GL tumors can be considered as a specific disease entity in feline lymphomas because the cases examined in this study showed onset at an older age, a low incidence of FeLV infection and frequent involvement of gastrointestinal lesions, which are not found in typical FeLV-associated lymphomas. Although no specific phenotypes was observed by phenotypic analysis, the feline GL tumor cells were divided into two consistent genotypes of T-cell or non-T- non-B-cell lineages.

Abdominal Neoplasms↗

PubMed1998

Displacement of platelets from blood to spleen following intravenous injection of liposomes encapsulating dichloromethylene bisphosphonate.

Liposomes encapsulating dichloromethylene bisphosphonate (Cl2MBP-liposomes) have been shown to cause selective depletion of phagocytic macrophages. We have shown that intravenous injection of Cl2MBP-liposomes into mice induces an almost complete depletion of F4/80-positive cells (mature macrophages) in the liver and in the splenic red pulp, but not in the lung. Platelets in the mouse contain a large amount of 5-hydroxytryptamine (5HT; serotonin) and so, by measuring 5HT, it is possible to assess the translocation of platelets to tissues. The injection of Cl2MBP-liposomes was found to induce a prolonged and marked increase in 5HT that occurred selectively in the spleen. On the other hand, 5HT in the blood decreased by as much as 50%. These changes in 5HT corresponded well with each other in terms of both time course and dose-response relationship. To judge from measurements made at the peak of the response, the 5HT increase in the spleen corresponded to about 80% of the 5HT lost from the blood. Electron microscopic analysis revealed a great accumulation of platelets in the splenic cords. We have shown that aggregation and degranulation of platelets in the lung is involved in rapid anaphylactoid shock induced within 10 min of intravenous injection into mice of a lipopolysaccharide [Shibazaki, M., Nakamura, M., Endo, Y., 1996. Biphasic, organ-specific, and strain-specific accumulation of platelets induced in mice by a lipopolysaccharide from Escherichia coli and its possible involvement in shock. Infect. Immun. 64, 5290-5294; Endo, Y., Shibazaki, M., Nakamura, M., Takada, H., 1997. Contrasting effects of lipopolysaccharides (endotoxins) from oral black-pigmented bacteria and Enterobacteriaceae on platelets, a major source of serotonin, and on histamine-forming enzyme in mice. J. Infect. Dis. 175, 1404-1412]. In the present study, it was found that such shock was almost completely prevented in those mice in which platelets were displaced from the blood by Cl2MBP-liposomes. These results suggest that in the spleen the depletion of phagocytic macrophages may impair the function or structure of this organ. This may lead to the entry of platelets into the spleen in such large numbers as to reduce their level in the blood and result in their prolonged accumulation in the spleen. The Cl2MBP-liposome may be an excellent tool for the in vivo investigation of the role of platelets, as well as that of macrophages.

Analgesics, Non-Narcotic↗

PubMed1998

Genetic heterogeneity of env gene of feline immunodeficiency virus obtained from multiple districts in Japan.

Feline immunodeficiency virus (FIV) infection is widespread in many countries. FIV isolates have been classified into five distinct subtypes, A, B, C, D and E based on their env gene sequences. Several reports indicate that most of the FIVs isolated in Japan belong to subtype B which includes the first Japanese isolate, TM2 strain. To examine the distribution of FIV subtypes in Japan, proviral DNA sequences of the env gene were directly amplified by nested PCR from FIV-infected cats that had been kept in multiple districts throughout Japan. Phylogenetic analysis of the 11 strains showed that four FIV subtypes, A, B, C and D, were present in Japan. Among these subtypes, subtypes B and D were the two most common subtypes in Japan, and they were mainly distributed in the eastern and western parts of Japan, respectively. The present study provides information that is fundamental for development of a vaccine to protect against FIV infection in cats.

Amino Acid Sequence↗

PubMed1998

Translocation of platelets into Disse spaces and their entry into hepatocytes in response to lipopolysaccharides, interleukin-1 and tumour necrosis factor: the role of Kupffer cells.

BACKGROUND/AIMS: Injection into mice of a small dose of either a lipopolysaccharide or interleukin-1 induces a slowly developing accumulation of 5-hydroxytryptamine, predominantly in the liver. We have established that this 5-hydroxytryptamine accumulation is the result of the translocation of platelets to hepatic sinusoidal spaces and, further, into Disse spaces, and that the platelets make direct contact with hepatocytes. In the present study, we report our recent findings on this phenomenon. METHODS: Platelets contain a large amount of 5-hydroxytryptamine, but the 5-hydroxytryptamine content of the liver is normally very small. Therefore, the translocation of platelets to the liver was assessed by measuring 5-hydroxytryptamine as in previous studies, and it was also analysed by electron microscopy. RESULTS: Anti-platelet agents, such as heparin and inhibitors of prostaglandin synthesis, were ineffective in preventing the lipopolysaccharide-induced accumulation of 5-hydroxytryptamine in the liver. Of the various cytokines tested, only interleukin-1 and tumour necrosis factor induced such an accumulation of 5-hydroxytryptamine. Intravenous injection of liposomes encapsulating dichloromethylene bisphosphonate resulted in an almost complete depletion of macrophages from the liver. The lipopolysaccharide- and cytokine-induced hepatic accumulations of 5-hydroxytryptamine were abolished almost completely in such macrophage-depleted mice. Electron microscopy revealed no accumulation of platelets in the liver after injection of lipopolysaccharide into the macrophage-depleted mice. Surprisingly, in normal mice injected with lipopolysaccharide, several platelets were found inside some hepatocytes, even though there was no visible damage to these hepatocytes. In fact, there were many polysomes around the degranulated platelets within the hepatocytes, suggesting an enhanced protein synthesis. CONCLUSION: These results suggest that, in response to lipopolysaccharide, interleukin-1 or tumour necrosis factor, platelets translocate into the liver in a way that is different from aggregation, and that some, at least, enter hepatocytes. During these processes, hepatic macrophages play an essential role.

Animals↗

PubMed1998

MASP1 (MBL-associated serine protease 1).

Mannose-binding lectin (MBL) is a serum component which participates in innate immunity by activating complement via a novel pathway. Human MBL forms complexes with two types of serine proteases termed MASP (MBL-associated serine protease). These two proteases, MASP1 and MASP2, are structurally similar to one another as well as to C1r and C1s. Together, MASP, C1r and C1s constitute a novel serine protease family. It is likely that human MASP1 is able to activate C3, while human MASP2 cleaves C4, although further functional studies are required to confirm this. Based on the analysis of MASP cDNA of vertebrates and ascidians, the MASP/C1r/C1s family can be classified into two groups. The first group is characterized by a histidine loop in its serine protease domain, an active-center serine encoded by TCN, and a proline as the amino acid residue at the-3 position from the active serine. Human MASP1, mouse MASP1, Xenopus MASP1 and ascidian MASPs all belong to this group. MASP of the second group has structural features which are distinct from those of the first group: an absence of a histidine loop, an active-serine encoded by AGY, and an alanine or valine as the amino acid residue at the -3 position from the active-serine. The second group includes human MASP2, Xenopus MASP2, carp MASP, shark MASP, C1r and C1s. The TCN-type of MASP may have emerged prior to the AGY-type as an ancestral protease of the MASP/C1r/C1s family and played a crucial role in cleaving C3.

Animals↗

PubMed1998

Complement-related serine proteases in tunicates and vertebrates.

Serum mannose-binding lectin binds to pathogens in association with a serine protease termed MASP, and in this form, plays a crucial role in innate immunity by activating complement in a manner similar to activation via the classical pathway. MASP, C1r and C1s belong to the same family of serine proteases. In addition to its presence in advanced species, MASP also exists in primitive life forms such as tunicates and may be an evolutionary prototype of this family.

Animals↗

PubMed1998

Influence of food consistency and dental extractions on the rat mandibular condyle: a morphological, histological and immunohistochemical study.

The purpose of this study was to investigate the relationship between food consistency and the growth of the mandibular condyle in rats. Secondly, the effect of dental extractions on cartilage of the mandibular condyle was examined in young adult rats fed foods of varying consistency. Thirty-six male Wistar rats were divided into four groups: (A) Solid diet--non-Extraction (non-Ext.) group; (B) Solid diet--Extraction (Ext.) group; (C) Powder diet--non-Ext. group; and (D) Powder diet--Ext. group. Extractions were performed at 12 weeks of age. The mandibular condyles were removed at 1, 4, and 8 weeks after the extractions. The shape of the mandibular condyles in the powder diet groups (C and D) was significantly narrower. In the Ext. groups (B and D), the thickness of the hypertrophic zone was reduced one week after the extractions. In the powder diet groups (C and D), the intensity of the staining of fibronectin decreased in the proliferative zone regardless of the extractions. In group B, a decreased intensity of this reaction was observed one week after the extractions. From these results, it appeared that food consistency and/or dental extractions affected the morphology of the mandibular condyle and the histological characteristics of the mandibular condylar cartilage.

Age Factors↗