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  • 1
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    The influence of vegetation and soil type on the speciation of iron in soil water (2012)
    Wiley-Blackwell
    Details
    Publication Date: 2012-04-24
    Description: Soluble organic matter derived from exotic Pinus species has been shown to form stronger complexes with iron (Fe) than that derived from most native Australian species. It has also been proposed that the establishment of exotic Pinus plantations in coastal southeast Queensland may have enhanced the solubility of Fe in soils by increasing the amount of organically complexed Fe, but this remains inconclusive. In this study we test whether the concentration and speciation of Fe in soil water from Pinus plantations differs significantly from soil water from native vegetation areas. Both Fe redox speciation and the interaction between Fe and dissolved organic matter (DOM) were considered; Fe – DOM interaction was assessed using the Stockholm Humic Model. Iron concentrations (mainly Fe 2+ ) were greatest in the soil waters with the greatest DOM content collected from sandy podosols (Podzols), where they are largely controlled by redox potential. Iron concentrations were small in soil waters from clay and iron oxide-rich soils, in spite of similar redox potentials. This condition is related to stronger sorption on to the reactive clay and iron oxide mineral surfaces in these soils, which reduces the amount of DOM available for electron shuttling and microbial metabolism, restricting reductive dissolution of Fe. Vegetation type had no significant influence on the concentration and speciation of iron in soil waters, although DOM from Pinus sites had greater acidic functional group site densities than DOM from native vegetation sites. This is because Fe is mainly in the ferrous form, even in samples from the relatively well-drained podosols. However, modelling suggests that Pinus DOM can significantly increase the amount of truly dissolved ferric iron remaining in solution in oxic conditions. Therefore, the input of ferrous iron together with Pinus DOM to surface waters may reduce precipitation of hydrous ferric oxides (ferrihydrite) and increase the flux of dissolved Fe out of the catchment. Such inputs of iron are most probably derived from podosols planted with Pinus .
    Print ISSN: 1351-0754
    Electronic ISSN: 1365-2389
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Wiley-Blackwell
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  • 2
    Electronic Resource
    Electronic Resource
    Cell therapy using microencapsulated 293 cells transfected with a gene construct expressing CYP2B1, an ifosfamide converting enzyme, instilled intra-arterially in patients with advanced-stage pancreatic carcinoma: a phase I/II study (1999)
    Springer
    Journal of molecular medicine 77 (1999), S. 393-398 
    Details
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001090050366
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Human cytomegalovirus in the pancreas of patients with type 2 diabetes: Is there a relation to clinical features, mRNA and protein expression of insulin, somatostatin, and MHC class II? (1992)
    Springer
    Virchows Archiv 421 (1992), S. 371-378 
    Details
    ISSN: 1432-2307
    Keywords: Type 2 (non-insulin-dependent) diabetes mellitus ; Human cytomegalovirus ; Major histocompatibility complex II ; Islet amyloid polypeptide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Human cytomegalovirus (HCMV) was recently demonstrated in the pancreas of about half the patients with type 2 diabetes mellitus in the absence of mumps, rubella or Coxsackie B virus. The present study addresses the question as to whether type 2 diabetes with an HCMV-positive pancreas differs from those with HCMV-negative pancreases with respect to age, sex, treatment, duration of disease, volume densities of B-cells and D-cells, mRNA levels of insulin and somatostatin, islet amyloid peptide deposits and major histocompatibility complex (MHC) class I and class II gene transcription, and protein expression. HCMV-positive type 2 diabetic patients showed a tendency towards a shorter duration of disease and significantly increased levels of MHC class II on RNA. In addition, expression of MHC class II product (HLA-DR) was identified in duct epithelial cells and/or islet cells in 9 diabetic pancreases and in 2 non-diabetic glands. No MHC class I expression could be detected. No other clinical differences between HCMV-positive and HCMV-negative glands were found. All 10 HCMV-positive diabetics showed a strong expression of MHC class II mRN in the pancreas. By immunocytochemistry, 4 of 10 demonstrated expression on the islets; three of ten also expressed MHC DRβ on ductal cells. This finding might be related to the viral infection, as only 2 of the 9 HCMV-negative patients were HLA-DRβ positive and none of the non-diabetic controls showed increased levels of MHC class II mRNA. These data suggest that HCMV infection in the pancreas is associated with type 2 diabetes. However, no conclusions as to a role of this virus in the aetiopathology of type 2 diabetes can be drawn at present.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606908
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  • 4
    Electronic Resource
    Electronic Resource
    Cystic fibrosis associated islet changes may provide a basis for diabetes (1989)
    Springer
    Virchows Archiv 414 (1989), S. 179-185 
    Details
    ISSN: 1432-2307
    Keywords: Cystic fibrosis ; Endocrine pancreas ; Immunocytochemistry ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The pancreases of 23 patients (mean age 10.5 years, range 5-22) years dying of cystic fibrosis (CF) were evaluated at autopsy by routine histology and immunostaining for changes in their endocrine cell compartment. The severely altered pancreatic tissues showed end stage CF, with either a fibrotic pattern (CF-FIB,n=14) or a lipoatrophic pattern (CF-LIP,n=9) prevailing. In all specimens, irrespective of the dominating pattern, the islet system was affected by marked periinsular and intrainsular sclerosis. Quantitatively, the volume densities (relative tissue components) of the parenchymal, fibrotic, fatty and total endocrine compartments as well as the four islet cell types (B, A, D, PP) were determined by point counting. Compared with controls, the CF patients (including two patients with overt diabetes and glucose intolerance, respectively) had a significantly decreased insulin (B)-cell ratio (from 64.4 to 34%) with a concomitant rise in non-B-cells (A-cells: 23.2 to 35%; D-cells: 10.4 to 22%; PP-cells; 2 to 9%). Comparison of endocrine cell ratios in CF-FIB pancreases with CF-LIP pancreases revealed no significant differences. The reduction of approximately 50% of insulin cells in CF patients with advanced disease supports the concept that destruction of exocrine tissue with concomitant fibrous disorganization of islets gradually changes the proportional distribution of the endocrine cells in favor of the noninsulin cells. This slowly ongoing process probably provides the basis for islet dysfunction, i.e. diabetes, increasingly observed in final stage CF.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00718598
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Residual insulin positivity and pancreatic atrophy in relation to duration of chronic Type 1 (insulin-dependent) diabetes mellitus and microangiopathy (1987)
    Springer
    Diabetologia 30 (1987), S. 757-762 
    Details
    ISSN: 1432-0428
    Keywords: Chronic Type 1 (insulin-dependent) diabetes ; residual insulin cells ; exocrine atrophy ; HLA-DR expression ; diabetic microangiopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The relationship of residual insulin positivity in chronic Type 1 (insulin-dependent) diabetes and atrophy of the exocrine pancreas to duration of diabetes, age at onset and microangiopathy was studied in 26 patients (disease duration 2 to 54 years, mean 26 years). Islets containing insulin cells were found in 13/26 pancreata. In 5/13 pancreata insulin positive cells were detected in only one lobule, while in 8/13 insulin positivity was multifocal. All patients with diabetes duration less than 11 years had residual insulin cells; whereas, the rate of insulin positivity was near 40% with diabetes duration of more than 11 and 21 years, respectively. Survival of insulin cells was not clearly related to age at onset. HLA-DR expression on insulin cells was seen in one case. Insulitis was lacking. Pancreatic volume determined in 18 patients ranged from 14–110 ml (age adjusted mean 56.3 ml) and was significantly less than that of control subjects (age adjusted, mean 89.9 ml, p〈0.0001). Computerized morphometry of the exocrine pancreas revealed severe acinar atrophy due to a reduction in size of acinar cells. Acinar atrophy correlated neither with the degree of insulin positivity, disease duration nor severity of microangiopathy. The findings suggest that in about 40% of patients with Type 1 diabetes a small population of insulin cells may escape autoimmune destruction, irrespective of disease duration or age at onset. Though exocrine atrophy and insulin deficiency are associated, the variable extent of pancreatic atrophy could not to be related to such factors as amount of surviving insulin cells, duration of diabetes or microangiopathy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00275740
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Prostaglandin analogue protects pancreatic B-cells against cyclosporin A toxicity (1989)
    Springer
    Cellular and molecular life sciences 45 (1989), S. 352-355 
    Details
    ISSN: 1420-9071
    Keywords: Cytoprotection ; cyclosporin ; endocrine pancreas ; insulin-secretion ; electron microscopy ; prostaglandin analogue ; rioprostil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cyclosporin A toxicity on pancreatic B-cells and its prevention by rioprostil, a prostaglandin E1 analogue, were studied in the model of the isolated perfused pancreas of rats treated with both compounds for 8 days. At toxic doses of cyclosporin (10 and 20 mg/kg b.wt), the B-cells showed severe hydropic degeneration of the endoplasmatic reticulum and slight degranulation of the B-cells. Accordingly, the insulin secretion was markedly impaired. Administration of rioprostil ameliorated the insulin secretion significantly, but not the ultrastructural changes. At therapeutic levels of cyclosporin (5 mg/kg b.wt), the hydropic degeneration and the drop in insulin secretion were completely prevented by rioprostil. This observation might have therapeutic implications in the treatment of patients, in particular those undergoing pancreatic transplantation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01957475
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