Biomedical subjects

Y Okada

Publications and source records attributed to Y Okada.

At least 271 records · Page 15Linked to original sources

PubMed2000

Adherence of Fusobacterium necrophorum subsp. necrophorum to ruminal cells derived from bovine rumenitis.

Fusobacterium necrophorum subsp. necrophorum strain VPI 2891 was shown to adhere to the surfaces of ruminal cells derived from bovine rumenitis. The strain also attached to bovine type 1 collagen. Treatment of the bacterium with antiserum to bacterial cells reduced attachment. The bacterial attachment was also markedly reduced when the ruminal cells had been pretreated with anticollagen serum. Fluorescence specific for the collagen was demonstrated on the surface of bovine tissue affected with rumenitis. These findings suggest that F. necrophorum subsp. necrophorum strain VPI 2891 adheres to the ruminal cells derived from rumenitis tissue and that the attachment may be mediated by cellular collagen.

Animals↗

PubMed2000

Magnetically suspended rotary blood pump with radial type combined motor-bearing.

A magnetically suspended centrifugal blood pump is being developed with a combined motor-bearing for long-term ventricular assist systems. The combined motor-bearing actively suspends a rotor in a radial direction to deal with radial force unbalance in the pump and rotates the rotor by using the electric magnetic field. Therefore, the pump has no mechanical parts such as bearings of the motor and has a long lifetime. The developed pump consists of a thin rotor with a semi open-type 6 vane impeller and a stator to suspend and rotate the rotor. The rotor has 4-pole permanent magnets on the circumferential surface. The outer diameter and the thickness of the rotor are 60 mm and 8 mm, respectively. Axial movement and tilt of the rotor are restricted by passive stability based on the thin rotor structure. Radial movements of the rotor, such as levitation in radial direction and rotation, are controlled actively by using electric magnets of the stator. The electric magnet coils to produce levitation and rotation forces are constructed on the periphery stator. The p +/- 2-pole algorithm and the synchronous motor mechanism are adopted to levitate and rotate the rotor. The radial gap between the rotor and the stator is 1 mm. A closed-loop circuit filled with water was connected to the developed pump to examine the basic performance of the pump and the magnetic suspension system. Maximum rotational speed, flow rate, and head were 2,800 rpm, 11 L/min, and 270 mm Hg, respectively. The rotor with the impeller could be suspended completely during the entire pumping process. We conclude the pump with the combined motor-bearing has sufficient performance for the blood pump.

Centrifugation↗

PubMed2000

Congenital ureteral diverticulum coexistent with hydronephrosis caused by vascular compression involving the uterine artery and umbilical ligament: report of a case.

Coexistence of congenital ureteral diverticulum and hydronephrosis caused by vascular compression is a rare entity. The authors experienced a case of congenital ureteral diverticulum coexistent with hydronephrosis caused by aberrant vascular compression by uterine and umbilical arteries in a 14-year-old girl. The authors could not diagnose accurately this abnormality preoperatively by 3-dimensional computed tomography. After partial ureterectomy, including resection of the saccular lesion and ureteroneocystostomy, the frequency of urinary tract infection decreased.

Adolescent↗

PubMed2000

Maternal blood coagulation factor XIII is associated with the development of cytotrophoblastic shell.

We analysed the early implantation tissues of normal women and of a patient with congenital factor XIII deficiency in order to study the role of maternal subunit A of factor XIII (XIIIA) in the development of extravillous cytotrophoblast. The patient had received adequate administration of factor XIIIA concentrate only up to 7 weeks of gestation (wG). Her pregnancy was maintained until the latter half of 8 wG, but was terminated by intrauterine fetal death at 9 wG. Immunohistochemical staining of cytokeratin, XIIIA and subunit S of factor XIII was performed in the early implantation tissues of normal women and of this patient. Numerous well-formed cytotrophoblastic shells and Nitabuch's layers were detected in implantation tissues at 7-8 wG in normal women, and XIIIA was present in the intercellular space in well-formed cytotrophoblastic shells, while the cytotrophoblastic shells and Nitabuch's layers in this patient's implantation tissue were poorly-formed. Furthermore, XIIIA was not detected around them. It is suggested that when the maternal plasma activity of factor XIII is low, the concentration of XIIIA at the placental bed is also low, leading to the insufficient formation of cytotrophoblastic shell and therefore an increased probability of miscarriage in patients with congenital factor XIII deficiency.

Adult↗

PubMed2000

Expression of involucrin by ocular surface epithelia of patients with benign and malignant disorders.

PURPOSE: Keratinization of the ocular surface epithelium is associated with various disorders impairing vision. We immunohistochemically determined whether the ocular surface epithelia express involucrin, and whether its expression pattern may differ in benign vs. malignant disorders. Expression of cytokeratins was also examined to provide further information relative to the epithelial differentiation. METHODS: We evaluated 17 specimens; 6 specimens of the normal ocular surface epithelia, 3 specimens from cases of conjunctival intraepithelial neoplasia (CIN), 6 of conjunctival squamous cell carcinoma (SCC) and 2 of conjunctivae from cases of superior limbic keratoconjunctivitis (SLK). RESULTS: Corneal epithelium exhibited intracellular immunoreactivity for involucrin. Four of the 6 specimens of bulbar conjunctival epithelium showed involucrin immunoreactivity in the perimembranous region, whereas the fornical conjunctiva was negative. Cornified envelope in SLK specimens was positive for involucrin. The CIN showed its immunoreactivity in the perimembranous region in all levels of the hyperproliferative epithelium without keratinization, i.e., similar to the bulbar conjunctiva. The neoplastic cells of well-differentiated SCC showed involucrin in the perimembranous region, and those of moderately- to poorly-differentiated SCC have involucrin in their cytoplasm. The expression pattern of cytokeratins was unrelated to grade of malignancy in ocular SCC. CONCLUSION: The epithelia of normal subjects and of CIN expresses involucrin without keratinization. In contrary, the keratinized SLK epithelium markedly expresses involucrin in the cornified envelope. The subcellular immunolocalization of involucrin in the ocular SCC may help in evaluating the differentiation, i.e., malignancy, of neoplastic cells.

Adult↗

PubMed2000

Immunohistochemical localization of MYOC/TIGR protein in the trabecular tissue of normal and glaucomatous eyes.

PURPOSE: To examine immunohistochemically the localization of myocilin/trabecular meshwork inducible glucocorticoid response (MYOC/TIGR) protein in the glaucomatous and normal trabecular meshworks. METHODS: Trabecular tissues were used from one eye with late-onset goniodysgenetic glaucoma, three with primary open angle glaucoma (one of which had the MYOC/TIGR gene mutation), two with exfoliation glaucoma and one without glaucoma. For light microscopic immunohistochemistry, frozen sections were stained by the avidin-biotin complex method using anti-MYOC/TIGR polyclonal antibody. For electron microscopic immunohistochemistry, the pre-embedding method using the same antibody was performed. Double immunostaining using both anti-MYOC/TIGR and anti-type VI collagen antibodies was done by the immunofluorescence method. RESULTS: With light microscopy, immunoreactivity was seen in the whole trabecular meshwork of each of the specimens. No notable differences were detected in staining among the types of glaucoma, or between the eyes with and those without the gene mutation. Under electron microscopy, immunoreaction products were observed not only in the cytoplasm of the trabecular cells but also in the extracellular matrix, where staining was associated with the long-spacing collagen, fine granular materials and possibly microfibrils. With double immunohistochemistry, MYOC/TIGR was colocalized with type VI collagen in the trabecular meshwork. CONCLUSIONS: In glaucomatous and normal trabecular meshworks, the MYOC/TIGR protein is distributed in the extracellular matrix colocalizing with type VI collagen.

Adolescent↗

PubMed2000

Matrix metalloproteinases and tissue inhibitors of metalloproteinases of fibrous humans lens capsules with intraocular lenses.

PURPOSE: We located immunohistochemically the matrix metalloproteinases (MMP) -1, -2, -3 and -9 and the tissue inhibitors of matrix metalloproteinases (TIMP) -1 and -2 in the fibrous capsule of patients with intraocular lenses (IOLs). METHODS: During vitreoretinal surgery in 10 patients we obtained post-cataract surgery lens capsules with or without an IOL. The mean interval between the previous cataract operation and the extraction of the specimens was 35.2 months (range: 2-120 months). Circular sections of the anterior capsule with lens epithelial cells (LECs) were also obtained during cataract surgery. Specimens were processed for immunohistochemical identification of MMPs and TIMPs by light microscopy. RESULTS: While all the members of MMPs and TIMPs were not detected in the normal anterior capsules, they were detected in the ECM and/or LECs on the lens capsules extracted within 18 months after IOL implantations in all of the 4 patients, but were not observed in specimens obtained 18 months or longer postoperatively. In LECs of 1 capsule specimen 10 years postoperatively, MMP-1, but not other MMPs and TIMPs, was detected. CONCLUSIONS: MMPs and TIMPs were detected in the ECM and/or LECs on post-cataract surgery capsules. These proteins may be remodeling the newly deposited ECM and regulating LEC behavior on residual lens capsules in the early phase of healing after cataract surgery.

Adult↗

PubMed2000

The origin of slow potentials on the tongue surface induced by frog glossopharyngeal efferent fiber stimulation.

When the glossopharyngeal (GP) nerve of the frog was stimulated electrically, electropositive slow potentials were recorded from the tongue surface and depolarizing slow potentials from taste cells in the fungiform papillae. The amplitude of the slow potentials was stimulus strength- and the frequency-dependent. Generation of the slow potentials was not related to antidromic activity of myelinated afferent fibers in the GP nerve, but to orthodromic activity of autonomic post-ganglionic C fibers in the GP nerve. Intravenous injection of atropine abolished the positive and depolarizing slow potentials evoked by GP nerve stimulation, suggesting that the slow potentials were induced by the activity of parasympathetic post-ganglionic fibers. The amplitude and polarity of the slow potentials depended on the concentration of adapting NaCl solutions applied to the tongue surface. These results suggest that the slow potentials recorded from the tongue surface and taste cells are due to the liquid junction potential generated between saliva secreted from the lingual glands by GP nerve stimulation and the adapting solution on the tongue surface.

Animals↗

PubMed2000

Preoperative concurrent chemoradiotherapy against muscle-invasive bladder cancer: results of partial cystectomy in elderly or high-risk patients.

BACKGROUND: Good local control has been reported in cases of muscle-invasive bladder cancer treated by chemoradiotherapy and transurethral resection (TUR). However, definitive irradiation or extensive chemotherapy is often intolerable for elderly or poor-risk patients. We report here benefits of partial cystectomy after concurrent low-dose chemoradiotherapy for high-risk patients. METHODS: Thirty-seven patients with localized muscle-invasive bladder cancer (T2-T4) were treated with concurrent cisplatin (50-100 mg/body x 2 courses) and pelvic irradiation (40 Gy) preoperatively. Among 17 patients (46%) who achieved complete response (CR), 10 were not suitable for radical cystectomy and underwent partial cystectomy. Radical cystectomy was performed in 24 cases [CR = 6, partial response (PR) = 18]. Two patients (one CR and one PR) rejected open surgery and were treated by TUR of the primary site. One no change (NC) patient received no further treatment because of mental disorder. RESULTS: Median follow-up was 12 months (range 2-37 months). Fifteen of 36 evaluable cases (42%) achieved a pathological T0 response (no residual tumor). Estimated 3-year disease-free survival was 56% for all patients and 100% for T0 responders. Seven of 21 patients with pathological persistent tumor developed local recurrence (three patients) or distant metastasis (four patients). All of the 10 patients (eight with T0 response and two with a small residual tumor nest) who underwent partial cystectomy were recurrence-free for an observation period of up to 3 years. CONCLUSIONS: Bladder preservation by partial cystectomy may be a choice for patients who show a good response to preoperative chemoradiotherapy and are not suitable for radical cystectomy.

Aged↗

PubMed2000

Crystal structure of the low-temperature phase of beta Cu1.75Se analysed by electron diffraction

The beta phase of Cu1.75Se has an anti-fluorite structure, where one in eight tetrahedral copper sites are vacant. Powder X-ray diffraction measurements on Cu1.75Se showed that the beta phase transformed to a two-phase mixture of (alpha + beta) at approximately 250 K, and then the beta phase changed to a new phase at approximately 180 K. Powder X-ray and electron diffraction measurements revealed that the low-temperature phase of the beta phase has a superstructure of (2alpha(fcc) x 2alpha(fcc) x 2alpha(fcc)) type, where alpha(fcc) is the lattice parameter of the original beta phase. The superstructure was interpreted to originate from the ordering copper vacancies. The new phase was referred to as the beta' phase.

Journal Article↗

PubMed2000

Bactericidal activity against coagulase-negative staphylococci is impaired in infants receiving long-term parenteral nutrition.

OBJECTIVE: To examine the role of total parenteral nutrition (TPN) in predisposing infants to infection caused by coagulase-negative staphylococci. SUMMARY BACKGROUND DATA: Total parenteral nutrition is an important means of providing essential nutrients to newborn infants. However, its use has been associated with complications, particularly infection caused by coagulase-negative staphylococci. Recent data suggest that TPN may modulate immune function; however, reports directly indicating impaired immunity against coagulase-negative staphylococci during TPN are limited. METHODS: Study 1 involved 31 infants younger than 4 months who had undergone surgery and were not receiving antibiotics; 20 were receiving TPN and 11 were receiving a normal enteral diet. An in vitro whole blood model was used to measure the host bactericidal activity against coagulase-negative staphylococci. Bacterial killing and phagocytosis were measured after a 45-minute challenge with viable coagulase-negative staphylococci. In study 2, whole blood killing and intracellular killing of coagulase-negative staphylococci were measured in five newborn infants (younger than 2 months) who were receiving long-term TPN (>10 days), five control infants receiving a normal enteral diet, and five healthy adults. RESULTS: In study 1, infants receiving a normal enteral diet showed a high capacity to ingest and kill coagulase-negative staphylococci. In contrast, the blood of infants receiving long-term TPN showed a reduction in coagulase-negative staphylococci phagocytosis and killing. There were significant negative linear correlations between the duration of TPN and killing of coagulase-negative staphylococci and phagocytosis of coagulase-negative staphylococci. In study 2, infants receiving long-term TPN had lower whole blood killing and intracellular killing than infants receiving a normal enteral diet and healthy adult volunteers. These data seem to indicate a neutrophil dysfunction mediated by TPN in infancy. CONCLUSIONS: Host defense mechanisms, including phagocytosis and killing of coagulase-negative staphylococci, are impaired during long-term TPN. The impaired bactericidal activity seems to be related to defective intracellular killing in neutrophils. These findings may explain the high rate of septicemia caused by coagulase-negative staphylococci in infants receiving TPN.

Adult↗

PubMed2000

Gastric metaplasia: a frequently overlooked feature of duodenal biopsy specimens in untreated celiac disease.

BACKGROUND: Duodenal gastric metaplasia is rarely reported in untreated celiac disease, although it is seen in 60% to 100% of duodenal biopsy specimens in nonceliac patients with histologic duodenitis. The low incidence could represent underreporting, a decreased incidence in pediatric patients generally, or the more distal sampling site that is customary for most biopsy specimens that are obtained to diagnose celiac disease. It could also be a unique feature of the inflammatory reaction that characterizes this disease. The purpose of this study was to examine the incidence of gastric metaplasia in duodenal specimens from children with untreated celiac disease with special reference to patient age and biopsy site. METHOD: Formalin-fixed paraffin-embedded specimens of duodenal mucosa were selected from the pathology department's archival material. Sections were either stained histochemically or by immunochemical methods, according to an antigen-retrieval protocol. Forty-four duodenal specimens from untreated patients with celiac disease (n = 22) and control subjects of similar age with normal histology (n = 22) were examined. Ten of each were obtained during upper endoscopy from the proximal duodenum (proximal site) and 12 of each by Crosby capsule near the ligament of Treitz (distal site). RESULTS: All specimens from patients with celiac disease exhibited marked villous atrophy. None had been noted to have gastric metaplasia during routine examination of sections stained by hematoxylin and eosin. Fifteen (68%) of 22 of the celiac specimens and 2 of 22 (9%) control specimens contained gastric metaplasia, identified as patches of gastric-type cells containing MUC5AC (gastric mucin), pS2 (gastric trefoil factor) and neutral (periodic acid-Schiff-positive) mucin. Five of the seven celiac specimens that had no metaplasia showed increased numbers of goblet cells expressing gastric markers. The incidence of gastric metaplasia was not different for endoscopic (70%) or capsule (67%) specimens. Sixty-eight percent (7/11) of patients aged less than 3 years had gastric metaplasia. CONCLUSION: The presence of gastric metaplasia has been previously underreported in celiac disease specimens. Detection would be improved by the routine use of period acid-Schiff/ alcian blue staining. The incidence of gastric metaplasia in celiac disease is not significantly influenced by biopsy site or age at time of the biopsy.

Age Factors↗

PubMed2000

Effects of the K+ channel opener KRN4884 on the cardiovascular metabolic syndrome model in rats.

We examined the effects of the potassium channel opener KRN4884 (5-amino-N-[2-(2-chlorophenyl)ethyl]-N'-cyano-3-pyridinecarboxamidine ) on cardiovascular metabolic syndrome (i.e., syndrome X), in rats. High-fructose diet rats developed hypertension, hypertriglyceridemia, increased total cholesterol/HDL (high-density lipoprotein)-cholesterol ratio, and hyperinsulinemia, KRN4884 (0.3-3.0 mg/kg, twice a day for 14 days, p.o.) alleviated the risk factors in fructose-fed rats. Furthermore, fructose-fed rats exhibited impairment of glucose tolerance and excess insulin secretion when loaded with glucose orally. Treatment with KRN4884 (1.0 mg/kg, twice a day for 14 days, p.o.) improved the glucose intolerance and inhibited hypersecretion of insulin in the glucose-loaded, fructose-fed rats. In contrast, KRN4884 (0.3-1.0 mg/kg, twice a day for 10 days, p.o.) did not affect serum triglyceride, cholesterol, glucose, or insulin concentrations in normal rats. LPL (lipoprotein lipase) activities in skeletal muscle and adipose tissue, and HTGL (hepatic triglyceride lipase) activity in liver were measured after administration of KRN4884 or vehicle twice a day for 14 days in fructose-fed rats. KRN4884 caused a significant increase in LPL activity in muscle and tended to increase LPL activity in adipose tissue in fructose-fed rats. HTGL was decreased in fructose-fed rats as compared with normal controls and was unaffected by KRN4884. These findings suggested that KRN4884 enhances insulin sensitivity and LPL activity, which are related to glucose and lipid metabolism and may be useful for the treatment of syndrome X.

Animals↗

PubMed2000

Surface cooling, which fails to reduce the core temperature rapidly, hastens death during severe hemorrhagic shock in pigs.

OBJECTIVE: To examine whether surface cooling (SC) would rapidly decrease the core temperatures and prolong the survival time during volume-controlled lethal hemorrhagic shock in pigs. METHOD: Twelve pigs were randomly assigned to the SC group (group 1, n = 6) or the no cooling control group (group 2, n = 6), after blood withdrawal of 30 mL/kg over 15 minutes, and maintained under spontaneous breathing by light anesthesia with 1.0% halothane. SC was performed by applying ethanol to the skin, blowing with an electric fan, and placing ice packs. Pigs were observed without fluid resuscitation until their death (apnea and no pulse). RESULTS: SC did not lower the rectal temperature (Tr) to 35 degrees C at any time point until death, except one pig; in that animal, Tr was decreased to 34 degrees C after 135 minutes from the start of SC. The survival time was 108 +/- 43 minutes in group 1 and 175 +/- 55 minutes in group 2 (p < 0.05, life table analysis). CONCLUSION: In lightly anesthetized pigs during hemorrhagic shock, SC without resuscitation did not rapidly reduce the core temperature and rather hastened death for reasons that remain to be explored.

Analysis of Variance↗

PubMed2000

A quantitative analysis of head injury using T2*-weighted gradient-echo imaging.

BACKGROUND: T2*-weighted gradient-echo imaging (T2*-GE) is useful for detecting small hemorrhages. METHODS: Thirty-four patients were prospectively examined, first by magnetic resonance imaging (1.5 T) and then by T2-weighted fast spin echo (T2-FSE) and T2*-GE. Thereafter, the correlations between the T2-FSE or T2*-GE findings and the clinical or computed tomography findings were analyzed. RESULTS: The number of lesions detected by T2*-GE was 14.5 +/- 16.3 (mean +/- SD, n = 34), which was significantly (p < 0.001) greater than that detected by T2-FSE (5.6 +/- 5.6, n = 34). The findings of T2*-GE correlated positively with both the duration of unconsciousness (R2 = 0.74,p < 0.0001) and with Glasgow Outcome Scale (R2 = 0.81, p < 0.0001), whereas those of T2-FSE did not show any significant correlation. T2*-GE imaging could also detect all areas responsible for focal neurologic signs 1 month after in. jury, whereas T2-FSE imaging detected only 22 of 33 such signs. CONCLUSION: T2*-GE was found to be useful for evaluating the clinical symptoms of head injury.

Adolescent↗

PubMed2000

Thermological study of drilling bone tissue with a high-speed drill.

OBJECTIVE: To perform a detailed quantitative analysis of the effect of intermittent drilling and irrigation to lower the temperature during high-speed drilling. METHODS: We examined the thermal changes for 15 bone flaps while drilling a 7- x 7-mm area for 18 seconds and a specific point for 9 seconds, under the following conditions: continuous or intermittent drilling; with a fluted steel or a diamond ball cutter; without or with irrigation, with room temperature or cold (8 degrees C) Ringer solution. RESULTS: The maximum temperature during continuous drilling with a diamond cutter (or steel cutter) was 82.4 +/- 1.3 degrees C (55.2 +/- 1.0 degrees C) without irrigation, 42.5 +/- 1.2 degrees C (35.4 +/- 0.9 degrees C) with room temperature Ringer irrigation, and 22.5 +/- 1.4 degrees C (21.6 +/- 0.3 degrees C) with cold Ringer irrigation, whereas that during intermittent drilling was 66.1 +/- 1.2 degrees C (35.6 +/- 0.8 degrees C), 35.0 +/- 0.8 degrees C (25.4 +/- 0.7 degrees C), and 21.5 +/- 0.6 degrees C (21.8 +/- 0.4 degrees C), respectively. During continuous drilling of a specific point, the radius of the concentric isothermal line for 43 degrees C (thermal threshold for neurons) was 3.6 +/- 0.8 mm with a steel cutter, and it was 8.1 +/- 0.3 mm with a diamond cutter. The radius was 4.2 +/- 0.8 mm during intermittent drilling with a diamond cutter, and it was 4.0 +/- 0.1 mm during continuous drilling with room temperature Ringer irrigation. Intermittent drilling with cold Ringer irrigation kept the temperature, even at the center of the drilled area, below 20 degrees C. CONCLUSION: Intentional intermittent drilling with irrigation reduces temperature elevation and its expansion. These procedures are necessary for safe drilling, especially with a diamond burr. Although cold irrigation can minimize temperature elevation, its substantial effect on nerves or other structures needs to be elucidated.

Adult↗

PubMed2000

Serological properties of Abiotrophia and Granulicatella species (nutritionally variant streptococci).

Serological variations were examined among 12 type or reference strains and 91 oral isolates of vitamin B6-dependent Abiotrophia and Granulicatella spp. Rabbits were immunized with whole cells of 12 selected strains and 10 typing antisera were obtained, which were unreactive with the Lancefield group A to G antigen preparations. The reactivity of the antisera and autoclaved cell surface antigen extracts was tested by double diffusion in agar gel and a capillary precipitin test. These typing antisera categorized all Abiotrophia defectiva strains, all except one Granulicatella elegans strain, three-quarters of the Granulicatella adiacens, and half of the Granulicatella paraadiacens into 8 serotypes and 2 subserotypes. The Granulicatella balaenopterae type strain was unserotypable. All A. defectiva strains were serotype I, some of which were divided into subserotype I-1 and/or I-5. The G. adiacens strains generally belonged to serotype II or III, and the G. paraadiacens strains to serotype IV, V or VI. All G. adiacens or G. paraadiacens serotype II strains were also subserotype I-5. The G. elegans strains were serotype VII or VIII. These Abiotrophia and Granulicatella serotypes were undetectable among 33 strains of the other 11 species including the bacteriolytic enzyme-producing but vitamin B6-independent strains of Streptococcus, Enterococcus, Dolosigranulum and Aerococcus. The proposed serotyping system for Abiotrophia and Granulicatella spp. would be helpful in the identification and classification of these unique coccal isolates in ecological and epidemiological studies.

Animals↗

PubMed2000

A novel experimental mouse model of peritoneal dissemination of human gastric cancer cells: different mechanisms in peritoneal dissemination and hematogenous metastasis.

We established a new cell line, AZ-P7a, with high peritoneal-metastatic potential in nude mice. AZ-P7a cells were derived from the human gastric carcinoma line AZ-521, which has low capacity for peritoneal dissemination. AZ-P7a cells developed peritoneal metastasis in 11 / 14 (78.6%) mice, whereas the parental AZ-521 cells developed metastasis in 2 / 6 (33.3%) mice. The metastatic foci in the peritoneum showed essentially the same histological appearance as those induced by parental cells. The tumorigenicity and the motile activity of AZ-P7a cells were stronger than those of the parental AZ-521 cells; in contrast, adhesion to the extracellular matrix and the production of vascular endothelial growth factor by AZ-P7a cells were decreased. In fluorescence-activated cell sorter (FACS) analysis, AZ-P7a cells expressed significantly greater levels of integrins alpha2, alpha3, alpha5, alpha6 and alphavbeta5, as compared with AZ-521 cells. However, alpha1, alpha4, alphavbeta3, hCD44H, hCD44v3, hCD44v6 and hCD44v10 were not expressed in either cell line. AZ-P7a cells developed no liver metastasis when administered by the intrasplenic injection method, though the highly liver metastatic cell line AZ-H5c showed the same rate of peritoneal dissemination as that exhibited by AZ-P7a cells after intraabdominal injection. These findings suggested that the mechanism of peritoneal dissemination differed from that of hematogenous metastasis. Moreover, the latter appears to be controlled by more complex mechanisms than the former. Thus, this cell line might be useful for investigating the mechanism of peritoneal dissemination of human gastric cancer.

Adenocarcinoma↗