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PubMed1988

Stable phenotypic expression of glutathione S-transferase placental type and unstable phenotypic expression of gamma-glutamyltransferase in rat liver preneoplastic and neoplastic lesions.

Using immunohistochemical demonstration of glutathione S-transferase placental type (GST-P) and histochemical demonstration of gamma-glutamyltransferase (gamma-GT), the long-term development of preneoplastic and neoplastic lesions was followed in rats over a 50-week period. Rats were given a single i.p. injection of 200 mg/kg body weight of diethylnitrosamine (DEN), and then 2 weeks later were administered 0.02% 2-acetylaminofluorene (2-AAF) (group 1), 0.05% phenobarbital (PB) (group 2), 2.0% butylated hydroxyanisole (BHA) (group 3) or no supplement (group 4) in their diet for 6 weeks, all rats being subjected to partial hepatectomy at week 3. Hepatocellular proliferated lesions were classified as foci, nodules and hepatocellular carcinomas. Development of foci, nodules and hepatocellular carcinomas was enhanced strongly by 2-AAF and weakly by PB, and inhibited by BHA. Almost all foci and nodules were GST-P positive, although 5-10% of the GST-P-positive foci were gamma-GT negative. The areas of GST-P-positive foci and nodules increased with time in all groups. In contrast, while the areas of gamma-GT-positive lesions also increased with time in groups 2-4, they decreased from week 12 in group 1. As the percentage gamma-GT-positive area in GST-P-positive foci significantly decreased with time in all groups, the rate of phenotypic reversion of gamma-GT in foci in group 1 was revealed to be larger than the focus growing rate, whereas that in groups 2-4 was smaller. Gamma-GT-negative and GST-P-positive micro-nodules of altered morphology appeared within gamma-GT- and GST-P-positive nodules in later stages. All hepatocellular carcinomas found in this experiment consisted of GST-P-positive cells. In contrast, 37% (13/35) of the hepatocellular carcinomas were negative for gamma-GT. The results indicate GST-P to be the most accurate marker enzyme for detection of initiated cells during liver carcinogenesis and gamma-GT to be more appropriate for indicating changes of phenotypic expression in each lesion type.

Animals↗
PubMed2001

Anticarcinogenic effect of red ginseng on the development of liver cancer induced by diethylnitrosamine in rats.

Anticarcinogenic effect of red ginseng (Panax ginseng C.A. Meyer cultivated in JiLin, China) on the development of liver cancer induced by diethylnitrosamine (DEN) in rats was studied, especially in preventive and curative groups. In the preventive group, the rats were given with DEN concomitantly with red ginseng fluid, and in the curative group, the rats were administered with red ginseng fluid after they developed liver cancer nodules induced by DEN. The result of the preventive group revealed that the developmental rate of liver cancer in the experimental group was 14.3%, while 100% in the control group, with the difference being statistically significant. DNA, RNA, glycogen, gamma-GT, SDH, and 5'-NT were maintained at relatively normal level in experimental group, and decreased or increased in the control group. The result of curative group showed that hepatoma nodules of the DEN-red ginseng group I were smaller than those of control group I, the structure of hepatic tissue was well preserved, the area with gamma-GT positive was smaller, and the ultrastructure of hepatocytes was normal. The average life span the DEN-red ginseng group II and the DEN control group II were 72.8 and 42.3 days, respectively. To sum up, all findings on preventive and curative groups had clearly proved that the red ginseng had the anticarcinogenic effect on the development of liver cancer induced by DEN in rats.

Animals↗
PubMed1990

Toxicological studies on a benzofurane derivative. I. A comparative study with phenobarbital on rat liver.

The benzofurane derivative benzbromarone (BBR) previously has led to liver tumor formation after long-term treatment of rats, but no indications of genotoxicity were detected. The present studies were designed to elucidate the mechanism(s) possibly involved in liver tumor formation by BBR. Female Wistar rats were used. Phenobarbital (PB) served as a positive control. (1) Short-term treatment (7 days) with daily doses of 2 to 100 mg/kg BBR led to adaptive responses in the liver, i.e., growth (increases in DNA, RNA, and protein) and induction of monooxygenases. These changes were also observed after feeding BBR for 8, 33, 77, and 102 weeks at doses of 2, 10, and 50 mg/kg/day but tended to weaken with time. Similar effects were obtained with PB fed at 2, 10, or 50 mg/kg/day. However, unlike PB, BBR did not enhance the expression of cytochrome P450-PB as demonstrated by immunostaining of histological liver sections. (2) BBR feeding for 102 weeks, but not for 77 weeks, produced some neoplastic liver nodules and at 50 mg/kg produced one hepatocellular carcinoma (HCC). Thus, BBR was tumorigenic in the present study, but was clearly weaker than PB which had induced liver nodules and HCCs at 77 weeks and even more markedly at 102 weeks. (3) To check for tumor-initiating activity 100 mg/kg BBR was given 14 hr after a two-thirds hepatectomy followed by promotion with PB (50 mg/kg) for 15 weeks. No phenotypically altered liver foci were detected. (4) To test for tumor-promoting activity rats received a single dose of N-nitrosomorpholine (250 mg/kg), and subsequently BBR or PB at doses of 2, 10, and 50 mg/kg/day. While PB markedly enhanced the development of neoplastic nodules and HCCs, BBR had only a weak enhancing effect on the induction of HCC, which was not dose related. gamma-glutamyl transpeptidase-positive foci dramatically increased in PB-treated animals, in contrast they showed no response after 2 and 10 mg/kg BBR and even decreased after 50 mg/kg BBR. (5) With PB changes in liver growth, monooxygenase activity, foci expansion, and tumor promotion all correlating with tumorigenesis in a quantitative manner, apparent no-observed-effect-levels are somewhat below 2 mg/kg (or 10 mg/kg for liver enlargement). (6) These studies suggest that BBR belongs to a group of nongenotoxic, growth-stimulating drugs with tumorigenic potential in rat liver. Its effects on the liver are different from those of PB, but seemed to resemble those of peroxisome proliferators, a hypothesis studied in the subsequent papers.

Animals↗
PubMed2003

Spontaneous development of hepatocellular carcinomas in the FLS mice with hereditary fatty liver.

The fatty liver Shionogi (FLS) mouse is an inbred strain that develops spontaneous fatty liver (hepatic steatosis) chronically without obesity. Here, we reported that the mice develop spontaneous hepatocellular tumors with high incidences. The mice with age of over 1 year frequently developed whitish protuberant nodules in the livers, which were histologically diagnosed as hepatocellular adenoma and/or carcinoma (HCC). An incidence of HCC was 12/30 (40%) in males at 15-16 months of age, while in females that was 0/36 at 13-16 months and 4/42 (9.5%) at 20-24 months. Furthermore, histological examinations showed that after 2-4 months of age mononuclear cell infiltration and clusters of foamy cells appear in the fatty liver with elevated serum alanine aminotransferase, suggesting presence of inflammatory responses and liver injury. These observations show that the FLS mice develop hepatocellular tumors following steatohepatitis. The mouse might be a good animal model for investigating liver tumor and non-alcoholic steatohepatitis.

Age Factors↗
PubMed1990

Nitrogen fixation of nodulation mutants of soybean as affected by nitrate.

It was previously reported that three soybean (Glycine max [L.] Merr.) nodulation mutants (NOD1-3, NOD2-4, and NOD3-7) were partially tolerant to nitrate when nitrate was supplied simultaneously with inoculation at the time of transplanting. The current study evaluated the effect of short-term nitrate treatment on nitrogenase activity (C(2)H(2) reduction per plant and per nodule weight) and on relative abundance of ureides when nitrate application was delayed until plants were 3 weeks old and nodules were fully developed. Nitrogenase activity of the mutants was similar to that of Williams after an initial 3-week growth period, prior to nitrate treatment. Application of 5 millimolar nitrate resulted in greater inhibition of nitrogenase activity in Williams than in the three mutants. NOD1-3 was most tolerant of nitrate among the mutants tested and showed the highest relative abundance of ureides. Although C(2)H(2) reduction activity per plant for NOD1-3 was higher than for Williams in the presence of nitrate, C(2)H(2) reduction activity per gram of nodules was lower for NOD1-3 than for Williams in the presence and absence of nitrate. Compared to Williams, NOD1-3 had higher nodule ureide concentration and had similar glutamine synthetase activity in nodule tissue, indicating its nodules have normal nitrogen assimilation pathways. Nitrate application resulted in ureide accumulation in nodule tissue as well as in all plant parts assayed. Unexpectedly, nitrate treatment also increased the rate of ureide degradative capacity of leaves in both NOD1-3 and Williams. The data confirmed that nitrogenase activity of the selected nodulation mutants was more, but still only partially, tolerant of nitrate compared with the Williams parent.

Journal Article↗
PubMed2001

Antiestrogenicity of clarified slurry oil and two crude oils in a human breast-cancer cell assay.

Exposure to crude oil and certain petroleum products can be a serious health hazard. Clarified slurry oil (CSO) is a complex mixture of hydrocarbons derived from the processing of crude oil, and is a known systemic and developmental toxicant, mutagen, and carcinogen. In the present study, CSO and two crude oils, Belridge heavy crude oil (BHCO) and Lost Hills light crude oil (LHLCO), were examined for their estrogenic and antiestrogenic properties in a human breast-cancer cell (MCF-7) assay. The MCF-7 focus assay is based on postconfluent cell growth and tissue restructuring, measured as the postconfluent development of multicellular nodules or foci. The mutagenicity indices of BHCO and LHLCO also were determined in a modified Ames Salmonella assay. Oil samples were prepared in dimethyl sulfoxide, resulting in extraction of virtually all of the aromatic compounds including the sulfur- and nitrogen-substituted three- to seven-ring polycyclic aromatic compounds comprising 62.2% of the CSO, 9% of the BHCO, and 2% of the LHLCO by total weight. None of the three samples was estrogenic in the MCF-7 focus assay. In contrast, all of the samples were antiestrogenic; that is, they inhibited the development of foci induced by 1 nM 17beta-estradiol (E2). The potencies of the oil samples for both antiestrogenicity and mutagenicity were correlated with the percent of polycyclic aromatic compounds they contained. Two potential mechanisms for the observed antiestrogenicity were examined. Radiometric analysis of the catabolism of [3H]E2 in MCF-7 cell cultures demonstrated that all three samples increased catabolism of E2. Results from a whole-cell estrogen-receptor (ER) binding assay suggested that metabolites of compounds in the oil samples might have competed with [3H]E2 for ER in the MCF-7 cultures. Thus the antiestrogenicity of the oil samples may occur through at least two mechanisms, increased catabolism of E2 and antagonistic binding to ER.

Binding, Competitive↗
PubMed1996

Silicotic lymph node reactions in mice: genetic differences, correlation with macrophage markers, and independence from T lymphocytes.

Quartz was injected into a hind food of BALB/c and DBA/2 mice and on days 40, 90, and 180 the progressive response ensuing in the draining popliteal lymph node (PLN) was investigated by histopathology and immunohistopathology. The area of silicotic nodules (ASN) was measured by morphometry, and, by this parameter, strain BALB/c proved to be a high responder to quartz, and strain DBA/2 a low responder, albeit both strains showed a similar degree of reactive lymphoid hyperplasia in the draining PLN. Both strains also showed a similar quartz content in the draining PLN but in BALB/c mice quartz particles were concentrated in the ASN, whereas in DBA/2 mice they were evenly dispersed over the PLN. Because the silicotic response of athymic BALB/c nu/nu mice was even stronger than that of euthymic BALB/c mice, T cells are not required for the development of silicotic nodules. This fits the notion that quartz is not an antigen and that high and low responder strains are MHC-identical. Because quartz-treated BALB/c, but not DBA/2 mice, showed a persistent expression of the macrophage differentiation markers MRP8 and MRP14, phenotypically the observed strain difference in silicotic responsiveness seems to be expressed at the level of macrophages.

Animals↗
PubMed2005

Visualization of nodulation gene activity on the early stages of Rhizobium leguminosarum bv. viciae symbiosis.

A technique was optimized for the in situ detection of nodulation (nod) gene activity in Rhizobium leguminosarum bv. viciae symbiosis with compatible plant hosts Vicia tetrasperma (L.) SCHREB. and Pisum sativum L. The transcription of nodABC-lacZ fusion was visualized as beta-galactosidase (beta-Gal) activity after reaction with the chromogenic substrate X-Gal and subsequent light microscopy, while the background of the indigenous beta-Gal activity of rhizobia and the host plant was eliminated by glutaraldehyde treatment. V. tetrasperma was suggested as a suitable model plant for pea cross-inoculation group due to its advantages over the common model of V. hirsuta (L.) S.F. GRAY: compactness of the plant, extremely small seeds, fast development and stable nodulation under laboratory conditions. In the roots of both plants, a certain extent of nod gene activity was detectable in all rhizobia colonizing the rhizoplane. In pea 1 d after inoculation (d.a.i.), the maximum was localized in the region of emerging root hairs (RH) later (3 and 6 d.a.i.) shifting upwards from the root tip. Nodulation genes sustained full expression even in the infection threads inside the RH and the root cortex, independently of their association with nodule primordia. Comparison of two pea symbiotic mutant lines, Risnod25 and Risnod27, with the wild type did not reveal any differences in the RH formation, RH curling response and rhizoplane colonization. Both mutants appeared to be blocked at the infection thread initiation stage and in nodule initiation, consistent with the phenotype caused by other mutant alleles in the pea sym8 locus. Judging from the nod gene expression level and pattern in the rhizoplane, flavonoid response upon inoculation is preserved in both pea mutants, being independent of infection thread and nodule initiation.

Bacterial Proteins↗
PubMed2004

Accelerated cutaneous nodulosis during infliximab therapy in a patient with rheumatoid arthritis.

Up to one fourth of patients with rheumatoid arthritis (RA) may have extraarticular findings such as subcutaneous nodules. These are discrete subcutaneous granulomatous nodules located on extensor surfaces, especially of the elbows. Over the past 10 to 15 years, there have been reports of accelerated cutaneous nodulosis in patients receiving methotrexate therapy. Recently, antitumor necrosis factor alpha (anti-TNFalpha) biologic therapy has become commonplace in the management of RA, especially in methotrexate-resistant or toxic patients. There have been recent reports of accelerated nodulosis in patients with RA on etanercept. We describe what we believe is the first case of accelerated cutaneous nodulosis resulting from infliximab anti-TNFalpha therapy in a patient with RA. One year after the initiation of infliximab, with RA in remission, our patient noted the rapid development of rheumatoid nodules of both hands. A biopsy was characteristic of a rheumatoid nodule, revealing palisading granulomas and fibrinoid necrosis.

Journal Article↗
PubMed1995

[Precancerous stages of hepatocellular carcinoma].

Precancerous stages of hepatocellular carcinoma (HCC) may be broadly categorized into three groups: high risk group, chronic liver diseases and adenomatous hyperplasia nodule. The high risk group for HCC has been clearly defined as the HCC which in Japan develops exclusively in patients with chronic liver diseases due to persistent infection of HBV or HCV. The mechanisms of HCC development by these hepatitis viruses have been partly clarified, and our study has shown it takes 25 years on average from HCV infection to the diagnosis of small HCC. Secondly, almost all cases of HCC are accompanied with chronic liver diseases, especially cirrhosis. Thus, cirrhosis has been considered as a precancerous stage. Recent studies indicated that BrdU labeling index is significantly increased in the non-cancerous cirrhotic portion in the cirrhotics with HCC, suggesting HCC develops in cirrhotics with high DNA synthetic potency of hepatocytes. Lastly, adenomous hyperplasia has also been considered a precancerous stage of HCC because early HCC is often seen in the nodule of this lesion. In addition, the early HCC nodules are diagnosed by serial liver biopsy in following patients with adenomatous hyperplasia. Thus, this lesion is considered the precancerous stage of HCC in a narrow sense. However, the early HCC nodules developing in adenomatous hyperplasia lesions are not all early HCC.

Carcinoma, Hepatocellular↗
PubMed1984

Cyclic modulation of enzymes of pyrimidine nucleotide biosynthesis precedes sialoglycoconjugate changes during 2-acetylaminofluorene-induced hepatocarcinogenesis in the rat.

Three enzymatic activities associated with pyrimidine nucleotide biosynthesis were monitored at weekly or bi-weekly intervals during 2-acetylaminofluorene- (0.025% in a Farber Basal Carcinogenic diet) induced hepatocarcinogenesis in the rat. Dihydroorotate dehydrogenase, the fourth of six enzymes in de novo pyrimidine biosynthesis, declined in activity while UDP kinase and CTP synthetase showed sequential increases in activity. The alterations in activity appeared to be cyclic, followed by a full or partial return to control values. Three full cycles were monitored. The first cycle preceded nodule formation. The second cycle accompanied nodule formation and preceded sialoglycoconjugate changes reported previously. The third cycle accompanied the early glycoconjugate changes. The cyclic pattern was reproducible in three separate experiments. In each cycle, the order of events was as follows: decrease in dihydroorotate dehydrogenase, sequential increases in UDP kinase, CTP synthetase and CMPsialic acid synthase, and finally increases in the enzyme lactosylceramide: CMPsialic acid sialyltransferase, lipid-soluble sialic acid and total sialic acid. In livers of animals fed 1.87% of the hepatotoxin, 4-acetamidophenol, no biochemical alterations resembling those induced by 2-acetylaminofluorene were obtained, despite acute centrilobular necrosis of the livers. The findings point to a biochemical cascade beginning with administration of carcinogen and continuing through the development of hyperplastic nodules and of frank carcinomas resulting not from hepatotoxicity but as events associated with the hepatocarcinogenic progression.

2-Acetylaminofluorene↗
PubMed2006

Pathogenesis, diagnosis and management of thyroid nodules in children.

According to the literature thyroid nodules are quite rare in the first two decades of life. However, there are some exceptions, relating to areas with an iodine deficiency or affected by radioactive fallout, where the risk of nodules and carcinomas is increased. Therefore, it is a great challenge for the physician to distinguish between benign and malignant lesions preoperatively, and not only in these areas of greater risk. A careful work-up, comprising the patient's history, clinical examination, laboratory tests, thyroid ultrasound, scintigraphy, fine-needle aspiration biopsy (FNAB) and molecular studies, is mandatory to improve the preoperative diagnosis. The differential diagnosis should also include benign thyroid conditions such as: (i) congenital hypothyroidism due to dyshormonogenesis or ectopy, (ii) thyroid hemiagenesis, (iii) thyroglossal duct cyst, (iv) simple goiter, (v) cystic lesion, (vi) nodular hyperplasia, (vii) follicular adenoma, (viii) Graves' disease and (ix) Hashimoto thyroiditis, all of which can predispose to the development of thyroid nodules. The majority of thyroid carcinomas derive from the follicular cell (papillary, follicular, insular and undifferentiated (or anaplastic) thyroid carcinoma), whereas medullary thyroid carcinoma derives from calcitonin-producing cells. Inherited forms of thyroid cancer may occur, especially in relation to medullary thyroid carcinoma. FNAB is a critical factor in establishing the preoperative diagnosis. However, we should keep in mind the fact that a conventional cytological evaluation can miss the neoplastic nature of a lesion and the employment of immunocytochemical and molecular studies of aspirates from FNAB can give us a more precise diagnosis of neoplasia in thyroid nodules once they are detected.

Biopsy, Fine-Needle↗
PubMed2001

Flavonoids induced in cells undergoing nodule organogenesis in white clover are regulators of auxin breakdown by peroxidase.

It was tested whether flavonoids that specifically accumulate in cells undergoing early nodule organogenesis could affect auxin turnover by a peroxidase to explain local changes in auxin distribution that occur during nodule formation in white clover (Trifolium repens cv. Haifa). A fluorometric assay was developed to determine the kinetics of indoleacetic acid (IAA) breakdown rates by a horseradish peroxidase in vitro. Three flavonoid compounds, which had previously been localized and identified, were purified from root tissue and their tissue concentrations estimated. A derivative of 7,4'-dihydroxyflavone (DHF), as well as free DHF, strongly inhibited auxin breakdown by peroxidase at concentrations estimated in the root tissue. Formononetin, an isoflavonoid accumulating in nodule primordia, accelerated auxin breakdown by peroxidase at concentrations estimated to be present in the roots. These results suggest that local changes in flavonoid accumulation could regulate local auxin levels during nodule organogenesis. The results are consistent with previous observations on the localization of auxin during nodule organogenesis. A model for the interaction of flavonoids with peroxidases is proposed to explain changes auxin during nodule development. A similar mechanism could be involved in lateral root and root gall formation.

Flavonoids↗
PubMed2006

Overlapping expression of ARFGEF2 and Filamin A in the neuroependymal lining of the lateral ventricles: insights into the cause of periventricular heterotopia.

Periventricular heterotopia (PH) is a malformation of cortical development characterized by nodules of neurons, ectopically located along the lateral ventricles of the brain. Mutations in the vesicle transport ADP-ribosylation factor guanine exchange factor 2 gene (ARFGEF2) or the actin-binding Filamin A (FLNA) gene cause PH. Previous studies have shown that FLNA expression is developmentally regulated, with strongest expression observed along the ventricular zone (VZ) and to a lesser degree in postmitotic neurons in the cortex. Here we characterize the expression patterns for ARFGEF2 within the central nervous systems of human and mouse in order to better understand their potential roles in causing PH. ARFGEF2 mRNA was widely expressed in all cortical layers, especially in the neural precursors of the ventricular and subventricular zones (SVZ) during development, with persistent but diminished expression in adulthood. ARFGEF2 encodes for the protein brefeldin-inhibited guanine exchange factor 2 (BIG2). BIG2 protein immunoreactivity was most strongly localized to the neural progenitors along the neuroependymal lining of the VZ during development, with decreased expression in adulthood. Furthermore, overlapping BIG2 and FLNA expression was greatest in these same neuroependymal cells of human embryonic brain and was co-expressed in progenitors by Western blot. Finally, transfection of a dominant-negative construct of ARFGEF2 in SHSY5Y neuroblastoma cells partially blocked FLNA transport from the Golgi apparatus to the cell membrane. These results suggest that mutations in ARFGEF2 may impair targeted transport of FLNA to the cell surface within neural progenitors along the neuroependyma and that disruption of these cells could contribute to PH formation.

Animals↗
PubMed1986

Sequential study on the synergistic effects of 2,2',4,4',5,5'-hexabromobiphenyl and 3,3',4,4',5,5'-hexabromobiphenyl on hepatic tumor promotion.

A sequential study was completed to determine the effect of polybrominated biphenyl (PBB) congeners on the enhancement of gamma-glutamyl transpeptidase (GGT)-positive altered hepatic foci (AHF) and the development of hepatic nodules (HN) and carcinomas. Female Sprague-Dawley rats were given a single dose of N-nitrosodiethylamine (NDEA) 24 h following a 70% partial hepatectomy. Thirty days later, rats were randomly assigned to groups and fed a basal diet or the basal diet containing 10 p.p.m. 2,2',4,4',5,5'-hexabromobiphenyl (245-HBB), 0.1 p.p.m. 3,3',4,4',5,5'-hexabromobiphenyl (345-HBB) or 10 p.p.m. 245-HBB plus 0.1 p.p.m. 345-HBB for 140 days followed by a basal diet for up to another 310 days. Rats from each group were killed 170, 240 or 480 days after partial hepatectomy. Dietary exposure to 245-HBB and 245-HBB plus 345-HBB enhanced the development of AHF and HN whereas 345-HBB alone did not. The combination of 245-HBB and 345-HBB caused a synergistic effect on the development of AHF and HN. The number of hepatocellular carcinomas was low and evenly distributed among the groups of rats fed diets containing PBB.

Animals↗
PubMedDate not supplied

Temporal arteritis in seropositive rheumatoid arthritis with rheumatoid nodule.

A 61-year-old woman, suffering from classic seropositive rheumatoid arthritis with rheumatoid nodule histologically documented, developed temporal arteritis. HLA-DR typing revealed the presence of DR3 and DR4 antigens. The findings from previous studies support the association of HLA-DR antigens, giant cell arteritis-polymyalgia rheumatica and rheumatoid arthritis, and suggest the participation of a common immunogenetic mechanism in their pathogenesis.

Arthritis, Rheumatoid↗
PubMed1995

The development of Azospirillum as a commercial inoculant for improving crop yields.

Bacteria of the genus Azospirillum are nitrogen-fixing organisms that live in close association with plants in the rhizosphere. The Azospirillum-plant association leads to the enhanced development and yield of different host plants under appropriate growth conditions. This increase in yield is attributed mainly to an improvement in root development, an increase in the rate of water and mineral uptake by roots, and to a lesser extent, biological N(2) fixation. Worldwide data accumulated in the field over the past 20 years indicates that Azospirillum is capable of promoting the yield of agriculturally important crops in different soils and climatic regions. A.brasilense shows both chemotaxis and chemokinesis in response to temporal gradients of different chemoeffectors, thereby increasing the chance of root-bacterial interactions. Phytohormones synthesized by Azospirillum influence the host root respiration rate, metabolism and root proliferation and hence better the mineral and water uptake in inoculated plants. Positive effects of combined inoculation with Rhizobium have been reported for different legumes and were related to the favorable influence of Azospirillum on the nodule number, plant development, dry weight, and N(2) fixation. Additionally, A. brasilense produces the reserve material polyhydroxybutyrate comprising up to 70% of the cell dry weight This substance has received much attention recently as it can be extracted and formed into a biodegradable thermoplastic.

Journal Article↗
PubMed1988

Expression of insulin-like growth factor I (IGF-I) and IGF-II mRNA during hepatic development, proliferation and carcinogenesis in the rat.

Insulin-like growth factor I (IGF-I) and IGF-II are peptides that presumably are required for normal fetal and postpubertal growth. The production of IGFs is developmentally regulated and the liver appears to be a major site of production. By analysing mRNA levels for IGF-I and IGF-II in the rat liver we have attempted to further study the expression of these growth factors during development and regeneration as well as during the course of hepatic carcinogenesis. Fetal livers are characterized by a high level of IGF-II mRNA and a low level of IGF-I mRNA, while in adult livers the opposite situations occur, i.e. a high level of IGF-I mRNA and a non-measurable level of IGF-II mRNA. During the course of experimentally induced hepatic cancer, IGF-I mRNA was consistently reduced and in a majority of cancers analysed (6/9) IGF-II mRNA was increased, i.e. a fetal type of IGF expression can be switched on in some experimentally induced hepatocellular carcinomas. The onset of IGF-II production during hepatic carcinogenesis appears to be a late phenomenon since liver nodules, preceding the development of hepatocellular cancer, were found not to contain IGF-II mRNA. Furthermore, during hepatic regeneration following partial hepatectomy no marked change in IGF-I or IGF-II mRNA levels was noted. The above results suggest that the fetal growth factor IGF-II could have a role in hepatic cancer.

Aging↗