Biomedical subjects

S Kita

Publications and source records attributed to S Kita.

At least 37 records · Page 2Linked to original sources

PubMed2000

[Development of artificial implant bone].

This study tested the hypothesis that a significant amount of the new bone produced by heterotopic periosteal grafts is derived osteoinductively because proliferating periosteal cells express the bone morphogenetic protein (BMP). Rabbit ulnar and radial periosteum were autografted as free grafts (FGs) to the forelimb musculature, and as millipore diffusion chambers grafts (MDCGs) to the rectus abdominus muscle. The sections were immunostained with monoclonal antibody against recombinant human (rh) BMP-2. Sections from FGs recovered 5 to 28 days postoperatively exhibited cartilage and bone; fibrous tissue, cartilage, bone, and osteochondroid differentiated within MDCGs. Although BMP-2 was expressed by mesenchymal cells, osteoblasts, osteocytes, and osteoclasts, none of the MDCGs produced the osteoinductive signature of transmembrane bone formation. These observations indicated that the larger fraction of the new bone produced by heterotopic periosteal autografts is derived from the graft cells. As the artificial implant bone, 1) the freeze-dried bone, 2) autoclaved bone, 3) sintered bone, 4) hydroxyapatite, and 5) titanium metal were used. Sprague-Dawley rats (aged 8 weeks) were used, the parietal bone was cut off, they were treated to freeze-dried bone, autoclaved bone and sintered bone. Then each treated bone was reimplanted. The grafts were harvested at 1, 2, 3, and 5 weeks postoperatively, the specimens were observed with a scanning electron microscope and a conventional light microscope. All of the treated bone were able to bone union, especially in the sintered bone and autoclaved bone, the blood vessels and the bone formation were produced at extremely early stage. In implantation of the non-living body materials, bone formation and revascularization was inhibited. We think that bone transplantation after irradiation should be done after recovery from the radiation damage to the periosteal cells and the blood vessels.

Animals↗

PubMed1999

Cloning and expression of a novel lysophospholipase which structurally resembles lecithin cholesterol acyltransferase.

Lecithin cholesterol acyltransferase (LCAT) is the key enzyme in the esterification of plasma cholesterol and in the reverse cholesterol transport on high-density lipoprotein (HDL). We have found a novel LCAT-related gene among differentially expressed cDNA fragments between two types of foam cells derived from THP-1 cells, which are different in cholesterol efflux ability, using a subtractive PCR technique. The deduced 412-amino-acid sequence has 49% amino acid sequence similarity with human LCAT. In contrast to the liver-specific expression of LCAT, mRNA expression of the gene was observed mainly in peripheral tissues including kidney, placenta, pancreas, testis, spleen, heart, and skeletal muscle. The protein exists in human plasma and is probably associated with HDL. Moreover, we discovered that the recombinant protein hydrolyzed lysophosphatidylcholine (lysoPC), a proatherogenic lipid, to glycerophosphorylcholine and a free fatty acid. We have therefore named this novel enzyme LCAT-like lysophospholipase (LLPL), through which a new catabolic pathway for lysoPC on lipoproteins could be elucidated.

Amino Acid Sequence↗

PubMed1999

An archetypical extradiol-cleaving catecholic dioxygenase: the crystal structure of catechol 2,3-dioxygenase (metapyrocatechase) from Ppseudomonas putida mt-2.

BACKGROUND: Catechol dioxygenases catalyze the ring cleavage of catechol and its derivatives in either an intradiol or extradiol manner. These enzymes have a key role in the degradation of aromatic molecules in the environment by soil bacteria. Catechol 2, 3-dioxygenase catalyzes the incorporation of dioxygen into catechol and the extradiol ring cleavage to form 2-hydroxymuconate semialdehyde. Catechol 2,3-dioxygenase (metapyrocatechase, MPC) from Pseudomonas putida mt-2 was the first extradiol dioxygenase to be obtained in a pure form and has been studied extensively. The lack of an MPC structure has hampered the understanding of the general mechanism of extradiol dioxygenases. RESULTS: The three-dimensional structure of MPC has been determined at 2.8 A resolution by the multiple isomorphous replacement method. The enzyme is a homotetramer with each subunit folded into two similar domains. The structure of the MPC subunit resembles that of 2,3-dihydroxybiphenyl 1,2-dioxygenase, although there is low amino acid sequence identity between these enzymes. The active-site structure reveals a distorted tetrahedral Fe(II) site with three endogenous ligands (His153, His214 and Glu265), and an additional molecule that is most probably acetone. CONCLUSIONS: The present structure of MPC, combined with those of two 2,3-dihydroxybiphenyl 1,2-dioxygenases, reveals a conserved core region of the active site comprising three Fe(II) ligands (His153, His214 and Glu265), one tyrosine (Tyr255) and two histidine (His199 and His246) residues. The results suggest that extradiol dioxygenases employ a common mechanism to recognize the catechol ring moiety of various substrates and to activate dioxygen. One of the conserved histidine residues (His199) seems to have important roles in the catalytic cycle.

Amino Acid Sequence↗

PubMed1999

Serum levels of soluble Fas ligand in patients with silicosis.

Certain patients with silicosis have been reported to exhibit immunological abnormalities such as the appearance of antinuclear antibodies and the occurrence of autoimmune diseases. Fas ligand (FasL) is a type II membrane protein which induces apoptosis by binding to its membrane receptor, Fas. FasL is converted to a soluble form by a metalloproteinase-like enzyme. We have already found serum soluble Fas (sFas) levels in silicosis patients as well as in patients with systemic lupus erythematosus (SLE) to be significantly higher than those in healthy volunteers. To examine further the role of the Fas/FasL system in silica-induced immunological abnormalities, we investigated serum soluble FasL (sFasL) levels in silicosis patients with no clinical symptoms of autoimmune diseases, using ELISA for sFasL. Although the serum sFasL levels in patients with SLE were significantly higher than those in healthy volunteers and showed a slight positive correlation with serum sFas levels, those in silicosis patients exhibited no significant difference from those in healthy volunteers, and there was no correlation with serum sFas levels. However, sFasL levels were elevated in silicosis patients with slight dyspnoea or normal PCO2 among various clinical parameters of silicosis. It may be speculated that the immunological disturbances presented by the abnormalities of apoptosis-related molecules in silicosis patients do not occur with a similar degree of respiratory involvement. Further studies are required to clarify which kinds of factors are involved in silicosis patients who exhibit immunological abnormalities.

Adult↗

PubMed1999

Evaluation of cases with silicosis using the parameters related to Fas-mediated apoptosis.

To establish a new clinical index for immunological abnormalities occurring in silicosis, several clinical parameters related to Fas-mediated apoptosis; i.e., membrane Fas expression on peripheral blood lymphocytes (mFas), serum soluble Fas levels (sFas), serum soluble Fas ligand levels (sFasL), and soluble/membrane Fas mRNA expression ratios (s/mFas ExR) in peripheral blood mononuclear cells (PBMC) were investigated. Fifty-eight silicosis patients with no clinical symptoms of autoimmune diseases were the subjects of this study. Factor analysis was performed using 12 clinical parameters including four parameters related to Fas-mediated apoptosis. Two common factors were identified. Factor 1 which consisted of the following parameters; duration of exposure, symptomatic dyspnea, PO2, PCO2, and A-aDO2, should be designated as the respiratory factor for cases with silicosis. The parameters of factor 2 were serum IgG, sFas with high factor loading, titer of ANA, sFasL, and s/mFas ExR. These parameters of factor 2 are indicative of the immunological disorders occurring in silicosis cases. Some cases exhibited abnormalities in parameters of factor 2 but not factor 1. The factor analysis clearly demonstrated that the parameters related to Fas-mediated apoptosis should be the most beneficial for predicting the pre-clinical status of complicated autoimmune diseases in silicosis.

Aged↗

PubMed1999

[Hidden chromosome instability and risk of laryngeal cancer incidence].

The bleomycin test is a recognised method of evaluation of hidden genetical instability. The concept of the test consists in inducing chromosome aberrations in lymphocytes exposed in vitro to bleomycin and subsequent quantitative analysis of chromosome breaks. The study material was whole venous blood from 61 laryngeal cancer patients and from 30 healthy persons taken as a control. For each patient two parallel cultures where carried out in the standard procedure. Bleomycin was added to one of the cultures to induce chromosome breaks. Then, in microscopic metaphasal plates stained by Giemsa dye, the chromosome instability index estimated as a number of chromosome breaks per cell (b/c) and the percentage of cells with chromosome breaks were calculated. Higher indices of chromosome instability were demonstrated in laryngeal cancer patients in comparison to the controls. The persons with chromosome instability (b/c > 0.8) or with chromosome oversensitivity to mutagens (b/c > 1) were identified only among larynx cancer subjects. Furthermore, it was established that an increased chromosome instability is associated with high aggressiveness recognised by histological grading. The latter finding requires confirmation on an enlarged group of subjects.

Adult↗

PubMed1999

[Estimation of bleomycin-induced chromosome aberrations in lymphocytes of laryngeal cancer subjects. Preliminary report].

Chromosome instability is associated with an increased risk of malignancy. However, the quantitative analysis of chromosome breaks provided by the bleomycin test requires additional analysis aimed for the localisation of chromosome aberrations. For this reason, the metaphasis slides prepared for bleomycin test were stained with fluorochrome DAPI to estimate chromosome breaks in particular chromosomes. The additional staining of chromosomes can be recognised as an extension of the classical bleomycin test addressed for identification of structural aberrations. Preliminary results indicate that the most frequent chromosome breaks were found in chromosomes 1, 2, 3, 7 and 13.

Aged↗

PubMed1999

[Chromosome damage in the course of laryngeal squamous cell carcinoma].

The aim of the article is a review of own cytogenic studies on laryngeal cancer confronted with the literature data. Spontaneous and bleomycin-induced chromosome instability was analysed in peripheral blood lymphocytes in relation to genetic risk of cancer incidence and progression. Comparative genome hybridization (CGH) was applied to demonstrate gains and losses of DNA copy number in tumour and non-tumour laryngeal mucosa. The profiles of imbalances of DNA copy number were shown to differ between metastazing and non-metastazing tumours. Preliminary data indicate a frequent loss of Y chromosome in tumour cells. The loss of heterozygosity at chromosome p53 locus (17p) has been shown to be more frequent than at chromosome locus coding 16 gene (9p). Altogether, the experiments have proven that a dynamics of chromosome aberrations is highest at the stage of metastasis.

Antibiotics, Antineoplastic↗

PubMed1998

Effects of endothelin-1 on norepinephrine-induced vasoconstriction in deoxycorticosterone acetate-salt hypertensive rats.

We investigated the effects of endothelin-1 on pressor responses to norepinephrine in perfused mesenteric arteries of deoxycorticosterone acetate (DOCA)-salt hypertensive rats. The response to norepinephrine (10(-6) M) was significantly increased in DOCA-salt rats compared with that in uninephrectomized control rats. Perfusion of the arteries with subpressor dose of endothelin-1 (3 x 10(-10) M) for 15 min markedly enhanced the pressor responses to norepinephrine (10(-6) and 3 x 10(-6) M) in control rats and this effect was significantly prevented by BQ788 [N-cis-2,6-dimethylpiperidinocarbonyl-L-gamma-methylleucyl-D -1-methoxycarbonyl-tryptophanyl-D-norleucine] (10(-6) M), but not by FR139317 ((R)2-[(R)-2-[(S)-2-[[1-(hexahydro-1H-azepinyl)]carbonyl]amino-4-+ ++methylpentanoyl]amino-3-[3-(1-methyl-1H-indoyl)]propionyl]ami no-3-(2-pyridyl)propionic acid) (10(-6) M). In DOCA-salt hypertensive rats, increased pressor response to norepinephrine was declined to the level of control rats by BQ788, but not by FR139317. In contrast to the case seen with control rat, exogenous endothelin-1 had little effect on pressor responses to norepinephrine in the arteries of DOCA-salt hypertensive rats. Total immunoreactive endothelin content in the arteries of DOCA-salt hypertensive rats was significantly higher than that of uninephrectomized control rats. These results suggest that endothelin-1 enhances contractile responses to norepinephrine through endothelin ETB receptor. Moreover, this phenomenon is stimulated tonically by endogenous endothelin-1 in DOCA-salt hypertensive rats and may contribute to the maintenance of hypertension in DOCA-salt rats.

Animals↗

PubMed1998

Novel non-peptide fibrinogen receptor antagonists. 1. Synthesis and glycoprotein IIb-IIIa antagonistic activities of 1,3,4-trisubstituted 2-oxopiperazine derivatives incorporating side-chain functions of the RGDF peptide.

Based on the lead tetrapeptide RGDF, two possible non-peptide glycoprotein (GP) IIb-IIIa antagonists possessing an (S)-2-oxopiperazine-3-acetic acid moiety as a scaffold incorporating the indispensable Asp fragment were prepared, and (S)-4-[[trans-[4-(guanidinomethyl)-cyclohexyl]carbonyl]glycyl]-2- oxopiperazine-1,3-diacetic acid, 1a, was identified as a potential lead. A series of 3-substituted 2-oxopiperazine-1-acetic acids bearing the Arg-Gly equivalent at the 4-position were prepared and evaluated for their ability to prevent platelet aggregation and for their binding affinity for the GP IIb-IIIa receptor purified from human HEL cells. (S)-4-[(4-Amidinobenzoyl)glycyl]-3-[(methoxycarbonyl)methyl]- 2-oxopiperazine-1-acetic acid, 9 (TAK-029), inhibited in vitro human platelet aggregation with an IC50 value of 0.03 microM and GP IIb-IIIa-fibrinogen binding with an IC50 value of 0.49 nM. The [4-(2-aminoethyl)benzoyl]glycyl derivative 26 showed activity comparable to that of 9 (IC50 = 0.093 microM, guinea pig platelet aggregation assay). Compound 9 dose-dependently inhibited ex vivo platelet aggregation in guinea pigs (0.03 and 0.1 mg/kg, i.v.), and long-lasting inhibition of platelet aggregation was observed upon oral administration of 9 (3 mg/kg) to guinea pigs. On the other hand, the activity of 26 disappeared within 1 h after a dose of 1 mg/kg (i.v.). Compound 9 may therefore be useful in the clinical treatment of arterial thrombotic diseases.

Animals↗

PubMed1998

Antihypertensive effect of a proteasome inhibitor in DOCA-salt hypertensive rats.

To search for a possible role for vascular proteasome in hypertension, we examined changes in proteasome level in aorta of deoxycorticosterone acetate (DOCA)-salt hypertensive rats and evaluated the antihypertensive effect of a proteasome inhibitor, N-benzyloxycarbonyl-Ile-Glu(O-t-Bu)-Ala-leucinal (PSI). Two weeks after the start of DOCA-salt treatment, the rats, with systolic blood pressure being 154 +/- 5 mmHg, were randomly divided into two groups and were given PSI or its vehicle for 2 weeks. Vehicle-treated DOCA-salt rats developed marked hypertension after 4 weeks (198 +/- 9 mmHg), with increases in aortic proteasome activity and content. The systolic blood pressure was positively correlated with both the content and activity of aortic proteasome. The administration of PSI to DOCA-salt hypertensive rats suppressed the elevation of systolic blood pressure (144 +/- 4 mmHg), accompanied by decreases in aortic proteasome activity and content. These results suggest that proteasome production in vascular tissues is increased in DOCA-salt hypertensive rats, and that PSI exhibits antihypertensive effect in this experimental hypertensive model. Thus, the findings indicate the pathophysiological importance of increased vascular proteasome in the development of DOCA-salt hypertension.

Animals↗

PubMed1998

Effects of acute or prolonged administration of cabergoline on parkinsonism induced by MPTP in common marmosets.

The effects of a single treatment or chronic administration of cabergoline (1-[(6-allylergolin-8beta-yl)carbonyl]-1-[3-(dimethylamino)p ropyl]-3-ethyl-urea), a potent, long-lasting dopamine receptor agonist, on parkinsonism induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in common marmosets were studied. The administration of 0.2 mg/kg or a higer dose of cabergoline began to reverse parkinsonism-like symptoms 60 min after a subcutaneous injection, and showed steady and constant effects throughout the observation period. For prolonged administration, 0.2 mg/kg cabergoline was injected daily for 22 consecutive days. Locomotor activity in MPTP-treated animals increased until it reached its peak on the third day, then it gradually decreased. Akinesia scores, rating the quality of movements, were also improved, and the improvement was sustained up to the last day of chronic administration. None of the animals developed abnormal behaviors after either acute or chronic administration. These results suggest that cabergoline has long-acting effects in the marmoset model of parkinsonism, and that it will be a useful agent for the treatment of Parkinson's disease, particularly in cases with fluctuating motor disabilities.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed1998

Soluble Fas mRNA is dominantly expressed in cases with silicosis.

Although it is well known that cases with silicosis exhibit various immunological abnormalities, the mechanisms involved in the occurrence of immuno-dysfunction or dysregulation induced by silica compounds have not yet been determined. Fas is a well-known cell surface molecule that is involved in the apoptosis pathway that belongs to the tumour necrosis factor-receptor family. Soluble Fas (sFas) is produced as an alternatively spliced product of the Fas gene and protects cells from apoptosis due to antagonization of the binding between membrane form of the Fas gene (mFas) and the Fas ligand. To determine the role of the Fas/Fas ligand system in silica-induced immunological abnormalities, we investigated Fas and Fas-ligand message expression levels using the multiplex reverse transcription-polymerase chain reaction (RT-PCR) method with peripheral blood mononuclear cells from silicosis cases with no clinical symptoms of autoimmune diseases. Although the relative expression levels of the Fas or Fas-ligand genes were not remarkably altered in these cases, we observed the sFas message was dominantly expressed compared with mFas expression. These results suggest that self-recognizing clones in cases with silicosis survive for decades, escaping the exclusion mechanisms induced by apoptosis. Then they cause the appearance of autoantibodies and the acquisition of autoimmune diseases sequentially.

Adult↗

PubMed1998

Endothelin-1 enhances pressor responses to norepinephrine: involvement of endothelin-B receptor.

We investigated the effects of endothelin-1 (ET-1) on pressor responses to norepinephrine (NE) in perfused rat mesenteric arteries. Perfusion of the arteries with a subpressor dose of ET-1 (3 x 10(-10) M) for 15 min markedly enhanced the pressor responses to NE (10(-6) and 3 x 10(-6) M), and this effect was significantly prevented by BQ788 (10(-6) M) but not by FR139317 (10(-6) M). In DOCA-salt hypertensive rats, exogenous ET-1 had little effect on pressor responses to NE. Pressor responses to NE (10(-6) M) were significantly increased in DOCA-salt rats compared with those in normotensive rats. This increased response to NE was reduced to the level of normotensive rats by BQ788. FR139317 was without effect on the increased responses. These results suggest that ET-1 enhances contractile responses to NE through ETB receptors. Moreover, this phenomenon is stimulated tonically by endogenous ET-1 in DOCA-salt hypertensive rats and may contribute to the maintenance of hypertension in these rats.

Adrenergic alpha-Agonists↗

PubMed1998

Antihypertensive effect of sesamin. III. Protection against development and maintenance of hypertension in stroke-prone spontaneously hypertensive rats.

The antihypertensive effect of sesamin, a lignan from sesame oil, was examined using salt-loaded and unloaded stroke-prone spontaneously hypertensive rats (SHRSP). The animals at 6 weeks of age were separated into a salt-loaded group and an unloaded group. Salt-loaded animals were maintained on 1% NaCl drinking water. Each group was further divided into two groups: normal-diet group and sesamin-diet group. Systolic blood pressure of all animals was monitored once weekly. At the end of the feeding periods, cardiovascular hypertrophy and renal damage were evaluated. In the salt-loaded group, sesamin feeding significantly suppressed the development of hypertension, and efficient suppression was maintained from 9 to 26 weeks (e.g., 215+/-4 vs. 180+/-4 mmHg, at 17 weeks old). The left ventricle plus septum weight-to-body weight ratio was slightly but significantly lowered by sesamin feeding. When the degree of vascular hypertrophy of the aorta and superior mesenteric artery was histochemically evaluated, wall thickness and wall area of these vessels were significantly decreased by the sesamin feeding. Histological renal damage such as thickening of the tunica intima and fibrinoid degeneration of the arterial wall were often observed in the normal-diet group, but this damage was efficiently reduced in the sesamin-fed animals. On the other hand, in the salt-unloaded group, only a slight and nonsignificant suppressive effect of sesamin on the development of hypertension was observed. Although the wall area of the aorta was significantly decreased by the sesamin feeding, other vascular parameters were not ameliorated. The incidence of histological renal damage tended to decrease in sesamin-fed animals, but these alterations were not statistically significant. Thus, sesamin feeding was much more effective as an antihypertensive regimen in salt-loaded SHRSP than in unloaded SHRSP, thereby suggesting that sesamin is more useful as a prophylactic treatment in the malignant status of hypertension and/or hypertension followed by water and salt retention.

Animals↗

PubMed1998

[Chromosome sensitivity to bleomycin-induced damage in patients with laryngeal cancer as a marker of genetic risk].

An inter-individual variability in sensitivity to mutagen-induced genotoxicity was studied in respect to an estimation of larynx cancer risk. Bleomycin induced chromosome breaks were analysed in blood lymphocytes proliferating in vitro in a group of 35 larynx cancer subjects and in 18 healthy controls. A significantly higher index of chromosome breaks was found in larynx cancer subjects as compared with the controls. The distribution of individual results indicates that subjects oversensitive to bleomycine were identified only among laryngeal tumour patients. A potential usage of bleomycin test in tumour prognosis is discussed.

Adult↗

PubMed1997

Platelets enhance contractility in perfused rat mesenteric arteries: involvement of endothelin-1.

We investigated the effects of platelet supernatant on pressor responses to norepinephrine in isolated perfused rat mesenteric arteries. Perfusion of the arteries with platelet supernatant for 2 h markedly enhanced the pressor responses to norepinephrine (10(-6) and 3 x 10(-6) M). This enhancement was significantly inhibited by phosphoramidon (10(-4) M), an endothelin converting enzyme inhibitor. Both BQ788 [N-cis-2,6-dimethylpiperidinocarbonyl-L-gamma-methylleucyl-D -1-methoxycarbonyltryptophanyl-D-norleucine] (10(-6) M), an endothelin ET(B) receptor antagonist, and bosentan (Ro47-0203, 4-tert-butyl-N-[6-(2-hydroxy-ethoxy)-5-(2-methoxy-phenoxy)-2,2-bipyri midin-4-yl]-benzenesulfonamide) (10(-5) M), a nonselective endothelin receptor antagonist, also prevented the potentiation of responses to norepinephrine evoked by platelet supernatant, but FR 139317 ((R)2-[(R)-2-[(S)-2-[[1-(hexahydro-1H-azepinyl)]carbonyl]amino-4-+ ++methylpentanoyl] amino-3-[3-(1-methyl-1H-indoyl)]propionyl]amino-3-(2-pyridyl) propionic acid) (10-6 M), an endothelin ET(A) receptor antagonist, had little effect. Suppressor doses of endothelin-1 (3 x 10(-10) M) or sarafotoxin S6c (S6c) (3 x 10(-10) M) potentiated significantly the norepinephrine-induced vasoconstriction, in the same preparation. Moreover, supernatant-induced enhancement of pressor responses to norepinephrine was markedly suppressed by TGF-beta1 neutralizing antibody. Transforming growth factor-beta1 (TGF-beta1) (40 pM) also significantly enhanced the pressor responses to norepinephrine (10(-6) M) and this enhancement was significantly inhibited by phosphoramidon. These results suggest that platelet-derived TGF-beta1 stimulates the vascular production of endothelin-1 and thereby enhances vasoconstrictor responses to norepinephrine. Platelet-induced enhancement of vasoconstrictor responses to norepinephrine seems to be mainly mediated by endothelin ET(B) receptor, in rat mesenteric arteries.

Animals↗

PubMed1997

Differentiation between benign and metastatic cervical lymph nodes with ultrasound.

OBJECTIVE: The differentiation between benign and metastatic lymph nodes with ultrasound (US) is based primarily on the evaluation of size, shape, margin and internal echo structure. The aim of this study is to determine whether these parameters are reliable indicators and to correlate internal echo structure and histopathological findings. MATERIALS AND METHODS: Seventy-one nodes in 21 patients with pathologically proven oral squamous cell carcinoma were examined. The shortest diameter, the short/long diameter ratio (S/L ratio), margins and internal echo structure of the lymph node were evaluated by US. The internal echo structure was divided into six patterns: homogeneous hypoechoic, homogeneous hyperechoic, heterogeneous, eccentric hyperechoic, centric hyperechoic and anechoic pattern. In addition, internal echo structure was correlated with histopathological findings. RESULTS: In 71.4% of the metastatic nodes, the shortest diameter was more than 10 mm and the S/L ratio was higher than that of benign nodes (average 0.71). Eleven (84.6%) of the 13 lymph nodes with irregular margins were metastatic. Heterogeneous and anechoic patterns were observed in metastatic nodes, whereas homogeneous hypoechoic and eccentric hyperechoic patterns were present in benign nodes. On ultrasonography with the corresponding histopathological findings, echogenic areas in the homogeneous hyperechoic, heterogeneous and centric hyperechoic patterns of metastatic nodes proved to be necrosis or fibrosis. Eccentric hyperechoic areas in benign nodes corresponded to the hilus and surrounding fatty tissue. CONCLUSIONS: The shortest diameter, S/L ratio, margin and internal echo structure were considered to be critical indicators to differentiate between benign and metastatic nodes. Secondary changes caused by tumour infiltration, necrosis, or fibrosis should be assessed when metastatic lymph nodes are differentiated from benign ones by internal echo structure.

Adult↗