Organization of extracellular matrix components during differentiation of adipocytes in long-term culture

Scanning electron microscopy (SEM) observation showed that fully differentiated spherical adipocytes were embraced by a network of collagens and fibroblastic preadipocytes. The properties of both the collagen networks and the preadipocytes allow the adipocytes to be interconnected, forming a fat-cell cluster, which can anchor to the bottom of a culture dish. In this network structure, collagen fibrils and fibrillar bundles were closely arranged and stratified. We found that immunostained collagens appeared to form extracellular network structures, which can be observed by SEM. The extracellular network of fibronectin was the first to develop among the extracellular matrix (ECM) components, though it became degraded with the progress of adipocyte differentiation. The type I collagen network was the last to develop and remained well organized through the late stage of adipocyte differentiation. The extracellular networks of type III, V, and VI collagen developed by the mid-stage and remained in the late stage of adipocyte differentiation. The network structures of type IV collagen and laminin became degraded during the differentiation process and localized at the surface of spherical cells. In addition to these basement membrane components, types III, V, and VI collagens also showed pericellular spherical staining patterns. These results demonstrated that the constitution and distribution of the ECM are altered during adipocyte differentiation, suggesting that the organization of each ECM component into a suitable structure is a requirement for the differentiation and maintenance of unilocular adipocytes.

Organization of extracellular matrix components during differentiation of adipocytes in long-term culture

Scanning electron microscopy (SEM) observation showed that fully differentiated spherical adipocytes were embraced by a network of collagens and fibroblastic preadipocytes. The properties of both the collagen networks and the preadipocytes allow the adipocytes to be interconnected, forming a fat-cell cluster, which can anchor to the bottom of a culture dish. In this network structure, collagen fibrils and fibrillar bundles were closely arranged and stratified. We found that immunostained collagens appeared to form extracellular network structures, which can be observed by SEM. The extracellular network of fibronectin was the first to develop among the extracellular matrix (ECM) components, though it became degraded with the progress of adipocyte differentiation. The type I collagen network was the last to develop and remained well organized through the late stage of adipocyte differentiation. The extracellular networks of type III, V, and VI collagen developed by the mid-stage and remained in the late stage of adipocyte differentiation. The network structures of type IV collagen and laminin became degraded during the differentiation process and localized at the surface of spherical cells. In addition to these basement membrane components, types III, V, and VI collagens also showed pericellular spherical staining patterns. These results demonstrated that the constitution and distribution of the ECM are altered during adipocyte differentiation, suggesting that the organization of each ECM component into a suitable structure is a requirement for the differentiation and maintenance of unilocular adipocytes.

Characterization of ethylene biosynthesis associated with ripening in banana fruit

We investigated the characteristics of ethylene biosynthesis associated with ripening in banana (Musa sp. [AAA group, Cavendish subgroup] cv Grand Nain) fruit. MA-ACS1 encoding 1-aminocyclopropane-1-carboxylic acid (ACC) synthase in banana fruit was the gene related to the ripening process and was inducible by exogenous ethylene. At the onset of the climacteric period in naturally ripened fruit, ethylene production increased greatly, with a sharp peak concomitant with an increase in the accumulation of MA-ACS1 mRNA, and then decreased rapidly. At the onset of ripening, the in vivo ACC oxidase activity was enhanced greatly, followed by an immediate and rapid decrease. Expression of the MA-ACO1 gene encoding banana ACC oxidase was detectable at the preclimacteric stage, increased when ripening commenced, and then remained high throughout the later ripening stage despite of a rapid reduction in the ACC oxidase activity. This discrepancy between enzyme activity and gene expression of ACC oxidase could be, at least in part, due to reduced contents of ascorbate and iron, cofactors for the enzyme, during ripening. Addition of these cofactors to the incubation medium greatly stimulated the in vivo ACC oxidase activity during late ripening stages. The results suggest that ethylene production in banana fruit is regulated by transcription of MA-ACS1 until climacteric rise and by reduction of ACC oxidase activity possibly through limited in situ availability of its cofactors once ripening has commenced, which in turn characterizes the sharp peak of ethylene production.

Population dynamics of nitrifying bacteria in an aquatic ecosystem

In a space environment such as Space Shuttle or Space Station, animal experiments with aquatic species in a closed system pose a crucial problem in maintaining their water quality for a long term. In nature, ammonia as an animal wastes is converted by nitrifying bacteria to nitrite or nitrate compounds, which usually become nitrogen sources for plants. Thus an application of the biological reactor with such bacteria attached on some filters has been suggested and experimentally studied for efficient waste managements of ammonia. Although some successful results were reported (Kozu et al. 1995, Nagaoka et al. 1998, Nakamura et al. 1997, 1998) in the space applications, purely empirical approaches have so far been taken to develop a biological filter having a stable nitrifying activity. In this study, we constructed a mathematical model to deal with the dynamics of the ammonia nitrifying processes in a biological reactor. The model describes population dynamics of the ammonia-oxidizing bacteria and the nitrite-oxidizing bacteria cultivated on the same filter. We estimated parameters involved in the model using the experimental data. The result shows that these estimated parameters could be applied to general cases and that the two bacteria are in a symbiotic relationship; they can better perform when both coexist, as has been empirically recognized. Based on the model analysis, we discuss how to prepare a high performance biological filter.

Teratogenicity of thujaplicin in ICR mice

Beta-thujaplicin (TP) was studied by in vitro and in vivo tests for teratogenicity using ICR mice. In the in vitro study, TP (0, 3.125, 6.25, 12.5 microg/ml medium) dissolved in dimethyl sulfoxide (DMSO) was administered to cultured embryos on 9 day of gestation. After 24 hr of exposure to TP, the embryos were examined for developmental parameters and external anomalies. Growth retardation and embryos with facial dysplasia or hydrocyst of the tail tip were observed among the embryos given 12.5 microg/ml. In the in vivo study, TP (0, 420, 560, 750 or 1000 mg/kg) dissolved in olive oil was administered orally to pregnant mice on day 9 of gestation. All foetuses were removed from the uterus on day 18 of gestation, and were examined for external and skeletal anomalies. Various types of malformations were observed in the mice given 560 mg/kg or more. The number of litters having foetuses with external or skeletal anomalies increased in proportion to the dose of TP. The regression lines of Y (probit response) on X (log dose) for external anomalies was Y = 4.87X-8.43 . The 1% effective dose (ED1) for the malformation was 190 mg/kg. The present study shows that TP has teratogenic effects on mice.

[Effect of vitamin A palmitate on vitamin A-deficient rabbits]

PURPOSE

We examined the effects of vitamin A palmitate (VA pal) eyedrops on the symptoms caused by vitamin A-deficiency in rabbits.

METHODS

Three-week-old rabbits were raised on a vitamin A-deficient diet, and were examined for the quantity of retinol in the serum and the condition of the anterior segment of the eye. The vitamin A-deficient animals were treated with VA pal eyedrops.

RESULTS

The retinol in the serum began to decrease seven months after the animals were placed on the vitamin A-deficient diet. After ten months, superficial punctate keratitis and the loss of conjunctival goblet cells were observed. Treatment of the disease in the anterior segment of the eyes with VA pal eyedrops resulted in restoration of normal condition within 3 weeks. The treatment increased the goblet cells in the ocular conjunctiva and the retinol in the serum.

CONCLUSIONS

These results show the efficacy of topical VA pal treatment for vitamin A-deficient rabbits.

Left sleeve pneumonectomy performed through a clamshell incision with extracorporeal membrane oxygenation for bronchogenic carcinoma: report of two cases

We report herein the cases of two patients with bronchial gland carcinomas in the left main bronchus who were successfully treated by left sleeve pneumonectomy performed through a clamshell incision. Adequate oxygenation during pathological examination of tumor invasion at the bronchial stumps and the tracheobronchial anastomoses was achieved by extracorporeal membrane oxygenation (ECMO) in both patients. Tracheobronchial anastomosis was relatively easy to perform in the excellent operative field achieved by this method. The postoperative courses of both patients were uneventful, although they developed temporary pulmonary edema that was effectively controlled by mechanical ventilation and appropriate diuresis. The procedure presented in this paper is considered to be a safe and effective method of performing left sleeve pneumonectomy.

Age-related changes in the response to thermal noxious heat and reduction of C-fibers by neonatal treatment with capsaicin

Developmental changes of the response to nociceptive heat were examined in mice treated with capsaicin (50 mg/kg) on postnatal days 2-15. Tests of hot-plate (55 degrees C) and irradiation by infrared (IR test) were carried out after 10 days of capsaicin administration up to 120 days at intervals of 10 or 20 days. The time until forepaw (hot-plate) and hindpaw (IR test) withdrawal was assessed as the response latencies to suprathreshold and thermal threshold, respectively. Moreover, the numbers of unmyelinated C-fibers and myelinated fibers in the L4 dorsal roots of the animals treated on postnatal days 2 and 5 were counted on electron micrograph montages. Despite the marked reduction of C-fibers (60% mean decrease) in the 4 dorsal roots of the animals treated on postnatal day 2, thresholds were normal compared with those of controls. However, the animals treated with capsaicin on postnatal day 5 showed an apparent delay of thermal threshold latency only in the IR test, although the mean reduction of C-fibers was very likely the same as that of the animals pretreated on day 2. The reduction of C-fibers in mice treated on postnatal days 10 and 15 was lower than the animals treated on days 2 or 5, but their threshold latencies were significantly increased (hypoalgesia). A possible implication of these findings is discussed on the basis of the development of inhibitory systems in the intraspinal and supraspinal dorsal horn and sprouting from the surviving primary afferent neurons in the superficial dorsal horn.

[Effect of vitamin A palmitate on the synthesis of mucins in cultured conjunctiva]

PURPOSE

To evaluate the effect of vitamin A palmitate on the synthesis of mucins from goblet cells in cultured rabbit conjunctiva.

METHODS

Palpebral conjunctiva was obtained from 12 white rabbits and was cultured in serum-free RCGM 2 which was developed for culture of rabbit corneal epithelial cells. This method eliminated retinol in the serum. High-performance liquid chromatography was used in quantitating N-acetylneuraminic acid contained in the sugar chain as an indicator of mucin content.

RESULTS

Addition of vitamin A palmitate to the cultured medium resulted in significant increase in the amount of N-acetylneuraminic acid in the medium.

CONCLUSIONS

The increase in N-acetylneuraminic acid in the cultured medium suggests that the increase of goblet cells in cultured conjunctiva is related to the synthesis of mucins due to vitamin A. RCGM 2 as a culture medium promises to be useful in evaluating the pharmacological activity of vitamin A. High-performance liquid chromatography facilitated quantitation of mucins in the culture medium.

Heterologous expression and product identification of Colletotrichum lagenarium polyketide synthase encoded by the PKS1 gene involved in melanin biosynthesis

The Colletotrichum lagenarium PKS1 gene was expressed in the heterologous fungal host, Aspergillus oryzae, under the starch-inducible alpha-amylase promoter to identify the direct product of polyketide synthase (PKS) encoded by the PKS1 gene. The main compound produced by an A. oryzae transformant was isolated and characterized to be 1,3,6,8-tetrahydroxynaphthalene (T4HN) as its tetraacetate. Since the PKS1 gene was cloned from C. lagenarium to complement the nonmelanizing albino mutant, T4HN was assumed to be an initial biosynthetic intermediate, and thus the product of the PKS reaction, but had not been isolated from the fungus. The production of T4HN by the PKS1 transformant unambiguously identified the gene to encode a PKS of pentaketide T4HN. In addition, tetraketide orsellinic acid and pentaketide isocoumarin were isolated, the latter being derived from a pentaketide monocyclic carboxylic acid, as by-products of the PKS1 PKS reaction. Production of the pentaketide carboxylic acid provided insights into the mechanism for the PKS1 polyketide synthase reaction to form T4HN.

UFT and mitomycin plus tamoxifen for stage II, ER-positive breast cancer. Hokkaido ACETBC Study Group

A trial was designed to examine the combination of UFT and mitomycin (Mutamycin) plus tamoxifen (Nolvadex) as postoperative adjuvant therapy in the treatment of patients with stage II, estrogen receptor (ER)-positive primary breast cancer. Mitomycin was administered intravenously at 13 mg/m2 on the day of surgery. Patients judged to be ER-positive were randomly allocated to either group A, which received oral tamoxifen 20 mg/day 14 days after surgery for 2 years, or group B, receiving oral UFT 400 mg/day plus tamoxifen 20 mg/day. A total of 219 patients were enrolled in group A, of which 213 (97.3%) were determined to be eligible; 225 patients enrolled in group B and 223 (99.1%) were eligible. The 5-year survival rates were 93.0% for group A and 95.4% for group B, with no significant difference between groups. The 5-year relapse-free survival rates were 83.1% for group A and 90.7% for group B, a significant advantage (P = .020) for the UFT plus tamoxifen group. Combination therapy with mitomycin, tamoxifen, and UFT proved to be an effective postoperative chemoendocrine therapy for stage II, ER-positive breast cancer.

Gastric cancer with sarcoid reactions in the regional lymph nodes, the stomach wall, and the splenic parenchyma: report of a case

A 66-year-old man was referred to our institute for investigation of heartburn and epigastralgia. Endoscopic examination demonstrated a type 4' gastric cancer which occupied the whole stomach. At laparotomy, multiple small nodules were found in the spleen which were diagnosed as metastases of the gastric cancer. Thus, total gastrectomy with distal pancreatectomy, splenectomy, cholecystectomy, and left adrenalectomy, combined with D4 lymph node dissection, was performed. Microscopic examination of the tumor revealed tubular and mucinous adenocarcinoma which invaded the muscularis propria. Sarcoid reactions were observed in the submucosa adjacent to the carcinoma tissue. Only one lymph node from station no. 8a demonstrated tumor metastasis, while those from station nos. 1, 2, 7, 8, 9, 10, 11, 13, and 16 revealed sarcoid reactions without tumor metastases. Subsequently, the multiple small nodules that had been presumed to be splenic metastases at laparotomy were found to be sarcoid reactions similar to those seen in the submucosa and regional lymph nodes. Since no skin or ocular lesions indicative of systemic sarcoidosis were seen in this patient, a diagnosis of advanced gastric cancer associated with sarcoid reactions was established. To our knowledge, there have been no previous reports regarding an association between sarcoid reactions in the spleen and gastric cancer.

Lower eyelid reconstruction with a cheek flap supported by fascia lata

The use of a cheek rotation flap is a well-known method for reconstruction of a large defect of the lower eyelid. In this technique, a separate lining tissue supporting the cheek flap is required for full-thickness reconstruction. Previously, a chondromucosal graft or conchal cartilage has been used to support this flap. Recently, we have used a homologous or autologous fascia lata as support for the cheek flap instead of rigid tissues like cartilages. A fascia lata strip is fixed with tolerable tension to the medial canthal tendon and lateral orbital rim. The inner surface of the fascia and the cheek flap is lined with a buccal mucosa graft to decrease irritation of the conjunctiva and cornea. We present here seven patients in whom this procedure was used for lower eyelid reconstruction following resection of a malignant skin tumor. Based on follow-ups of 7 to 22 months, the functional and aesthetic results have been good in all cases. This procedure may be applicable for total or subtotal reconstruction of the lower eyelid.

Three-dimensional computed tomographic angiography in lower extremity revascularization

To evaluate the role of three-dimensional computed tomographic angiography (3D-CT) in peripheral artery bypass surgery, 49 patients with chronic lower limb ischemia underwent 3D-CT before and after a bypass operation. 3D-CT had a sensitivity of 96.8%, a specificity of 95.0% and an overall accuracy of 96.1% for the diagnosis of arterial and graft stenosis or obstructions. The ability to observe the acquired images at any angle was very useful for assessing the implanted graft in both aortoiliac and infrainguinal bypasses. Although these images equally identified arterial stenosis, obstruction, and the anastomotic morphology of bypass grafts as well as conventional angiography, the diagnostic accuracy was not helpful in the small arteries and grafts. 3D-CT is a low-invasive imaging method that is sufficient for forming strategies for bypass operations. In aortofemoral or femoropopliteal bypass surgery, 3D-CT thus provides sufficient imaging accuracy for bypasses up to the popliteal artery below the knee in patients with chronic limb ischemia.

RGS7 and RGS8 differentially accelerate G protein-mediated modulation of K+ currents

The recently discovered family of RGS (regulators of G protein signaling) proteins acts as GTPase activating proteins which bind to alpha subunits of heterotrimeric G proteins. We previously showed that a brain-specific RGS, RGS8 speeds up the activation and deactivation kinetics of the G protein-coupled inward rectifier K+ channel (GIRK) upon receptor stimulation (Saitoh, O., Kubo, Y., Miyatani, Y., Asano, T., and Nakata, H. (1997) Nature 390, 525-529). Here we report the isolation of a full-length rat cDNA of another brain-specific RGS, RGS7. In situ hybridization study revealed that RGS7 mRNA is predominantly expressed in Golgi cells within granule cell layer of cerebellar cortex. We observed that RGS7 recombinant protein binds preferentially to Galphao, Galphai3, and Galphaz. When co-expressed with GIRK1/2 in Xenopus oocytes, RGS7 and RGS8 differentially accelerate G protein-mediated modulation of GIRK. RGS7 clearly accelerated activation of GIRK current similarly with RGS8 but the acceleration effect of deactivation was significantly weaker than that of RGS8. These acceleration properties of RGS proteins may play important roles in the rapid regulation of neuronal excitability and the cellular responses to short-lived stimulations.

Lack of somatic mutation in the PTEN gene in squamous cell carcinomas of human skin

The tumor suppressor gene PTEN is deleted and/or mutated in a variety of tumors and the susceptibility gene for Cowden disease. Loss of heterozygosity of chromosome 10q23, where PTEN resides, in squamous cell carcinomas (SCCs) of human skin and the association of SCC with Cowden disease were reported previously. In the present study, we screened for mutations of PTEN in SCCs by polymerase chain reaction single strand conformation polymorphism analysis to examine whether PTEN is involved in the carcinogenesis of SCC. None of 21 SCCs showed somatic mutations in the coding regions of PTEM. Instead the same allelic variation was detected in two cases without any clinical features of Cowden disease. Our results indicate that inactivation of PTEN does not play an important role in the carcinogenesis of SCC.

Immunosuppression with FK506 in rat arterial allografts: fate of allogeneic endothelial cells

PURPOSE

This study clarified the efficacy of low-dose FK506 and the possibility of discontinuing the use of FK506.

METHODS

Fresh carotid arteries were allografted from ACI rats to Lewis rats. FK506 (0.2 mg/kg/day) was given intramuscularly from day 3 after transplantation until the rats were killed (group III), or it was given for 4 weeks and then discontinued (group IV). Isogeneic (group I) and allogeneic (group II) models served as untreated control groups. Grafts were harvested on days 0, 1, 3, 7, 14, 21, 28, 70, and 105 after transplantation. Histological evaluation and measurement of the endothelial cell (EC)-covered area were performed by means of scanning electron microscopy.

RESULTS

In group I, ECs were denuded immediately after transplantation and subsequently regenerated within 2 weeks. In group II, after denudation and regeneration of ECs, massive leukocyte adhesion and subsequent destruction of regenerated ECs, followed by intimal hyperplasia, were observed. In group III, FK506 suppressed rejection almost completely, without intimal hyperplasia. In group IV, severe rejection and denudation of regenerated intima appeared 2 weeks after the use of FK506 ended.

CONCLUSION

The denudation and regeneration of ECs may play an important role in the process of rejection and graft performance. FK506 proved to be successful in rat arterial allografting, and ECs of donor origin could survive on the allograft as long as FK506 was effective; however, cessation of the use of FK506 resulted in severe destruction of intima. To prevent allograft failure, long-term administration of an immunosuppressant is essential.

Regulation of histamine synthesis in mouse CD4+ and CD8+ T lymphocytes

OBJECTIVES

Previously, we have shown that mouse T lymphocytes produce de novo histamine in response to mitogens. The aim of this study was to examine which subsets of T cells produce histamine and to clarify the regulatory mechanisms of the reaction.

MATERIALS

CD4+ and CD8+ T lymphocytes were separated from spleen cells of mast cell-deficient WBB6/F1 (W/Wv) mice using anti-CD4- and anti-CD8-coupled magnetic beads, respectively.

RESULTS

Both CD4+ T cells and CD8+ T cells released histamine when treated with Con A as a function of incubation time. Since histamine bound to each cell fraction was negligible before and after the treatment, it is highly likely that this indicates de novo synthesis of histamine by these cells. Granulocyte/macrophage colony-stimulating factor (GM-CSF) or IL-3 strongly enhanced the Con A-induced histamine formation. IL-1-alpha also potentiated the Con A-dependent histamine production. Dexamethasone, but not progesterone, significantly inhibited the Con A-dependent as well as Con A-independent histamine synthesis. Both GM-CSF and IL-3 caused a marked accumulation of histidine decarboxylase (HDC, EC 4.11.22) mRNAs in the cells.

CONCLUSIONS

These results suggest that GM-CSF and IL-3 enhance histamine synthesis in CD4+ T cells and CD8+ T cells.

Protection against endothelial abnormalities by a novel calcium channel blocker, AE0047, in stroke-prone spontaneously hypertensive rats

We investigated the protective effect of chronic treatment with AE0047, a dihydropyridine-type calcium channel blocker, on vascular endothelial abnormalities in stroke-prone spontaneously hypertensive rats (SHRSP). Ten-week repeated antihypertensive treatment with AE0047 inhibited blood pressure elevation and improved endothelium-dependent relaxation in response to acetylcholine in aorta isolated from SHRSP. Furthermore, the abnormal production of prostaglandin I2 and thromboxane A2 in the aorta was normalized to a level equivalent to that in Wistar-Kyoto rats. These results suggest that chronic treatment with AE0047 exerts protective effects against endothelial abnormalities associated with the development of hypertension.

Two distinct mechanisms operate in the reactivation of heat-denatured proteins by the mitochondrial Hsp70/Mdj1p/Yge1p chaperone system

The yeast mitochondrial Hsp70, Ssc1p, functions as a molecular chaperone with its partner proteins, Mdj1p (DnaJ homologue) and Yge1p (GrpE homologue). We have purified a mature form of Ssc1p from yeast mitochondria and those of Mdj1p and Yge1p from Escherichia coli overexpresser cells. With these purified components of the mitochondrial Hsp70 chaperone system, we have succeeded in reconstituting their chaperone functions in the protection of firefly luciferase against thermal damage in vitro. Heat-denatured luciferase is prevented from irreversible aggregation and is maintained in a refolding-competent state by Ssc1p and/or Mdj1p at 42 degreesC. Luciferase denatured at 42 degreesC is actively reactivated by Ssc1p, Mdj1p and/or Yge1p after lowering the temperature to 25 degreesC. The reactivation process of heat-denatured luciferase shows two-phase kinetics. The slow refolding process requires either Ssc1p or Mdj1p at 42 degreesC but the presence of Ssc1p, Mdj1p and Yge1p, and ATP hydrolysis, is essential at 25 degreesC. The slow refolding of luciferase involves multiple rounds of formation and dissociation of the complex between luciferase and Mdj1p/Ssc1p. On the other hand, the fast refolding process is most enhanced when luciferase is incubated with Ssc1p alone at 42 degreesC, and it requires neither the assistance of Mdj1p and Yge1p nor ATP hydrolysis. We have observed a similar two-pathway reactivation of heat-denatured luciferase by the bacterial Hsp70 and the yeast cytosolic Hsp70 systems.

Expression characteristics of CS-ACS1, CS-ACS2 and CS-ACS3, three members of the 1-aminocyclopropane-1-carboxylate synthase gene family in cucumber (Cucumis sativus L.) fruit under carbon dioxide stress

We investigated the expression pattern of three 1-aminocyclopropane-1-carboxylate (ACC) synthase genes, CS-ACS1, CS-ACS2 and CS-ACS3 in cucumber (Cucumis sativus L.) fruit under CO2 stress. CO2 stress-induced ethylene production paralleled the accumulation of only CS-ACS1 transcripts which disappeared upon withdrawal of CO2. Cycloheximide inhibited the CO2 stress-induced ethylene production but superinduced the accumulation of CS-ACS1 transcript. At higher concentrations, cycloheximide also induced the accumulation of CS-ACS2 and CS-ACS3 transcripts. In the presence of CO2 and cycloheximide, the accumulation of CS-ACS2 transcript occurred within 1 h, disappeared after 3 h and increased greatly upon withdrawal of CO2. Inhibitors of protein kinase and types 1 and 2A protein phosphatases which inhibited and stimulated, respectively, CO2 stress-induced ethylene production had little effect on the expression of these genes. The results presented here identify CS-ACS1 as the main ACC synthase gene responsible for the increased ethylene biosynthesis in cucumber fruit under CO2 stress and suggest that this gene is a primary response gene and its expression is under negative control since it is expressed by treatment with cycloheximide. The results further suggest that the regulation of CO2 stress-induced ethylene biosynthesis by reversible protein phosphorylation does not result from enhanced ACC synthase transcription.

Induction of B-cell lymphoma in BALB/c nude mice with an ecotropic, B-tropic helper virus present in the murine AIDS virus stock

The pathogenicities of the murine AIDS (MAIDS) virus complex (LP-BM5) and ecotropic helper virus (BM5eco) isolated from the complex to BALB/c nude mice were studied to elucidate the possible role of replication-competent helper virus in inducing the monoclonal outgrowth of lymphoid cells. Neither LP-BM5 nor BM5eco was pathogenic in adult BALB/c nude mice. However, B-cell lymphoma developed with a very high frequency when either virus was inoculated into newborn BALB/c nude (nu/nu) mice. The cells from the B-cell lymphoma were easily transplanted into nude mice. These results suggested that ecotropic helper virus in the MAIDS virus complex plays an important role in inducing the monoclonal outgrowth of lymphoid cells under immunodeficient conditions caused by defective virus.

Pathological analyses of early recurrence and malignant transformation in meningiomas

We investigated factors of the early recurrence and malignant transformation of histologically benign meningiomas using immunohistochemistry for MIB-1 positive indices (PI) and p53 protein expression, a flow cytometric DNA analysis, and the examination of numerical chromosomal aberrations detected by fluorescence in situ hybridization using an alpha-satellite DNA probe and a bcr gene locus-specific probe. Twenty-six meningiomas of 23 patients were classified into two groups: the 3 patients in whom a recurrence was defined within two years after initial surgery and who showed histologically malignant features were classified as the early recurrent group, and the other 20 patients in whom recurrence did not develop during the same period were classified as the nonrecurrent group. DNA aneuploidy was observed in 40% of the nonrecurrent patients and in 67% of the early recurrent patients. Loss of chromosome 22 was the most common numerical aberration, but the aberrations characteristic of early recurrent meningiomas were not detected. The MIB-1 PI values of the early recurrent meningiomas were higher than those of nonrecurrent meningiomas, suggesting that MIB-1 PI is very important for biological and histopathological analyses and prediction of the future recurrence of meningiomas.

Propensity of ectopic liver to hepatocarcinogenesis: case reports and a review of the literature

Two patients with ectopic liver are described. In one patient, a small ectopic liver attached to the gastric serosa developed hepatocellular carcinoma (HCC). The preoperative diagnosis was an alpha-fetoprotein (AFP)-producing carcinoma and a malignant ulcer of the stomach. Total gastrectomy and esophago-jejunostomy were performed. The tumor that measured 4 x 2 x 2 cm contained an AFP-producing HCC and normal liver tissue. In another patient who had alcoholic cirrhosis, ectopic liver on the serosa of the gallbladder was found to have the same histological changes as the mother liver. A survey of the literature disclosed more than 20 cases in which HCC developed outside the liver; the liver did not have HCC. By contrast, there was only one report on HCC occurring in the liver in the presence of a noncancerous, relatively large accessory liver lobe. Because ectopic liver does not have a complete vascular and ductal system as a normal liver, it is perhaps functionally handicapped and more prone to hepatocarcinogenesis.