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  • Cell & Developmental Biology  (6)
  • albuminuria  (3)
  • Principal components analysis  (2)
  • 1
    ISSN: 1432-0428
    Keywords: Diabetes ; hypertension ; nephropathy ; enalapril ; albuminuria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study has evaluated the effects of the angiotensin converting enzyme inhibitor Enalapril on glomerular ultrastructure and albuminuria in normotensive and hypertensive diabetic rats. Streptozotocin-diabetes was induced in Wistar Kyoto and spontaneously hypertensive rats. Enalapril was administered in drinking water in diabetic normotensive, control hypertensive and diabetic hypertensive rats. Enalapril therapy prevented an increase in glomerular basement membrane thickness in diabetic normotensive, control hypertensive and diabetic hypertensive rats without any significant effect on fractional mesangial volume. Enalapril decreased albuminuria in diabetic normotensive, control hypertensive and diabetic hypertensive rats. Thus, enalapril retards the development of glomerular basement membrane thickening and albuminuria in the rat, in the presence or absence of hypertension.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0428
    Keywords: Diabetic nephropathy ; albuminuria ; apoprotein(a) ; blood pressure ; Type 2 (non-insulin-dependent) diabetes mellitus ; Type 1 (insulin-dependent) diabetes mellitus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study has explored the temporal relationship between apoprotein(a), blood pressure and albuminuria over a mean interval of 11 years in a cohort of 107 diabetic patients of whom 26 (14 Type 2 (non-insulin-dependent), 12 Type 1 (insulin-dependent) had progressively increasing albuminuria (‘progressors’). In Type 2 diabetic patients, no significant differences were noted for HbA1, blood pressure, creatinine clearance or serum lipids between progressors and non-progressors. In Type 1 diabetic patients, final systolic and diastolic blood pressures were higher in progressors compared with non-progressors and progressors showed impairment of renal function in association with a rise in blood pressure at the macroalbuminuric stage. Initial apoprotein(a) levels were similar in progressors and non-progressors of either diabetes type. Apoprotein(a) levels increased exponentially with time in 12 of 14 Type 2 progressors but only in 5 of 12 Type 1 progressors (p〈0.01). In Type 2 diabetic patients, the annual increase in apoprotein(a) levels was 9.1±2.4%, which was significantly greater than in non-progressors, 2.0±1.2% (p〈0.01) and also exceeded the rates of increase of apoprotein(a) in progressors with Type 1 diabetes, 4.0±1.4%, (p〈0.05). Apoprotein(a) levels correlated significantly with albuminuria in 8 of 14 Type 2 progressors but only in 3 of 12 Type 1 progressors (p〈0.05). The rate of increase of apoprotein(a) levels was not related to mean HbA1, creatinine or creatinine clearance levels, or to albuminuria. The rate of rise of apoprotein(a) was not influenced by initial apoprotein(a) levels, suggesting that specific apoprotein(a) isoforms do not influence albuminuria-related increases in apoprotein(a). The data are consistent with the hypothesis that apoprotein(a) levels increase in response to albuminuria and may be part of a self-perpetuating process. This study also suggests that increases in apoprotein(a) levels commence during the microalbuminuria stage in diabetic patients, which is earlier than has been documented in non-diabetic proteinuria.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0428
    Keywords: Diabetic nephropathy ; albuminuria ; aldose reductase inhibitors ; prostaglandins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of two structurally unrelated aldose reductase inhibitors, sorbinil and ponalrestat, on glomerular prostaglandin production and urinary albumin excretion was investigated in rats with diabetes induced by streptozotocin. It was found that both aldose reductase inhibitors, when administered from the time of induction of the diabetes, significantly decreased the raised urinary albumin excretion in the diabetic rats, although it remained elevated compared with non-diabetic rats. Glomerular prostaglandin E and 6-ketoprostaglandin F1α production was significantly increased in glomeruli obtained from the diabetic rats. Inhibition of aldose reductase caused a reduction in the raised glomerular prostaglandin production, although this remained above that observed in the non-diabetic rats. Subsequent experiments were performed to determine whether the effects of the aldose reductase inhibitors could be explained by effects on glomerular filtration rate. It was found that ponalrestat, at a dose which markedly reduced urinary albumin excretion, did not significantly affect glomerular filtration rate in non-diabetic rats, rats with untreated streptozotocin-induced diabetes and rats with diabetes partially treated with low dose insulin. Glomerular sorbitol concentrations were significantly elevated in untreated diabetic rats as early as two weeks after the induction of diabetes. It is concluded that the administration of aldose reductase inhibitors from the time of induction of diabetes significantly reduces glomerular prostaglandin production and urinary albumin excretion. The latter effect is not due to an effect on glomerular filtration rate. Increased polyol pathway activity may account in part for the increased glomerular prostaglandin production and urinary albumin excretion in early experimental diabetes.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Plant ecology 51 (1983), S. 141-155 
    ISSN: 1573-5052
    Keywords: Correlation matrix ; Dispersion matrix ; Forest model ; Hierarchical structure ; Ordination ; Principal components analysis ; Simulation ; Succession
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A model of a 1/12th ha forest stand, FORET, generated 10 000 years of simulated species succession. Approximately the first third of these results were analyzed by principal component analysis as if they were collected field data to give the trajectory of the community particle in a collapsed species space. The ordination axis orientation was performed on a dispersion matrix and correlation matrix between species. In both cases, however, the eigen vectors were applied to the data matrix which had not been transformed to unit species variance. This facilitated comparison of species dispersion and correlation structure; it emerged they were very different. Correlation structure gave large weights to understory species while dispersion emphasized the dominant overstory species. This implies a decomposition of simulated stand behavior into overstory and understory, even though such decomposition was not formally built into the model. This decomposition would seem to pertain to real vegetation. Principal component analysis was able to express insightful differences between data structure with and without the unit variance transformation implicit in the correlation matrix. This flexibility of the ordination method proved valuable in uncovering unsuspected ordering principles in the model. Complex simulated data allow the ordination technique to demonstrate its capacity to generate new hypotheses, which hypotheses can then be simply validated by a return to the structure of the model but with the hindsight of the analysis. The generation of new hypotheses is not possible if the simulation is of a simple coenocline; on the other hand, ordination of test field data does not allow the simple validation of new hypotheses, for in the field there is not a defined algorithm to which the researcher can return.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Plant ecology 56 (1984), S. 147-160 
    ISSN: 1573-5052
    Keywords: Data transformation ; Ordination ; Phytoplankton ; Principal components analysis ; Scale
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Data transformation is seen here as an aspect of scaling such that we are less interested in the quirks and properties of each transformation but are more concerned with the general scaling properties and trends of suites of transformations. Over two years of daily phytoplankton abundance data for 30 species from a temperate lake (Llyn Maelog, North Wales) were subjected to a series of scale-ordered transformations. Two major classes of transformation were systematically varied: binary and smoothing. Binary transformation scaled the cutoff threshold between ‘presence’ and ‘absence’ of a species to various levels of abundance. With successively smaller universes and smoothing windows and successive species exclusion, ordinations of sample dates revealed smaller scaled structures in the order: annual cycles of species turnover, seasonal areas of attraction and uniqueness of individual sample dates. Gradual increases in the length of the smoothing window resulted in gradual shifts in the positions of points in sample data ordination, but not necessarily in the species ordinations. Thus sample data structures are more stable with change in scale than are species data structures. These differences in stability are discussed in the context of filtering characteristics of data collection and data analysis. Transformations producing similar species statistics (means, variances and skews) did not generally give similar ordination results, while some transformations giving similar ordinations differed in species statistical parameters.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: With the aid of a multipotent stem cell line (FDCP-mix cells) co-cultured with either normal or irradiated Swiss 3T3, cellular interactions between stromal cells and haemopoietic stem cells were studied by electron microscopy and time-lapse video microscopy. When cultured in the presence of interleukin 3 (IL-3) but in the absence of stromal cells, the FDCP-mix cells have a characteristic blast morphology. In the absence of IL-3, the cells die unless they are co-cultured with marrow stromal cells or 3T3 cells. In the latter case, they attach, proliferate, and differentiate on both normal and irradiated Swiss 3T3 cell layers without the addition of extrinsic growth factor (IL-3). At the initial attachment sites of these two cell lines, cellular recognition seemed to be mediated by the formation of microvillus cytoplasmic projections and extracellular matrix. These areas may well be the sites of plasma-membrane-bound signalling/adhesional molecules between the interacting cells.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The introductory review amplifies the finding that simply holding lymphocytes in vitro reversibly compromises their ability to enter lymph nodes from the blood, although entry into the spleen is unaffected. The differential migration of T and B lymphocytes from the blood, lymphocyte traffic in athymic rats, and the secretion of a sulphated glycoconjugate by high endothelial cells in lymph nodes are also discussed.Original data are presented concerning the effects of varying the conditions under which lymphocytes are held in vitro (time, temperature, medium, centrifugation) on their ability to enter lymph nodes and also on their surface morphology. In general, conditions that reduced the number of microvilli and induced surface blebbing also tended to affect the delicate function of crossing specialized vascular endothelium; but there was no simple relationship between morphology and migratory behavior. The localization of lymphocytes to the bone marrow was augmented by holding them in vitro, and this effect was greater after holding at room temperature (RT) than at 0°C, in contrast to impaired entry into lymph nodes. Small amounts of heparin (10 units) injected along with lymphocytes significantly reduced early localization in lymph nodes. These findings have practical implications for the design of lymphocyte traffic experiments and are relevant to the mechanism of lymphocyte attachment to vascular endothelium, since the well-known effect of trypsinizing lymphocytes can be reproduced by maintenance in vitro.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 91 (1977), S. 335-344 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A liquid culture system is described whereby proliferation of haemopoietic stem cells (CFU-S), production of granulocyte precursor cells (CFU-C), and extensive granulopoiesis can be maintained in vitro for several months. Such cultures consist of adherent and non-adherent populations of cells. The adherent population contains phagocytic mononuclear cells, “epithelial” cells, and “giant fat” cells. The latter appear to be particularly important for stem cell maintenance and furthermore there is a strong tendency for maturing granulocytes to selectively cluster in and around areas of “giant fat” cell aggregations. By “feeding” the cultures at weekly intervals, between 10 to 15 “population doublings” of functionally normal CFU-S regularly occurs. Increased “population doublings” may be obtained by feeding twice weekly. The cultures show initially extensive granulopoiesis followed, in a majority of cases, by an accumulation of blast cells. Eventually both blast cells and granulocytes decline and the cultures contain predominantly phagocytic mononuclear cells.Culturing at 33°C leads to the development of a more profuse growth of adherent cells and these cultures show better maintenance of stem cells and increased cell density.When tested for colony stimulating activity (CSA) the cultures were uniformly negative. Addition of exogenous CSA caused a rapid decline in stem cells, reduced granulopoiesis and an accumulation of phagocytic mononuclear cells.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 82 (1973), S. 461-473 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A liquid culture system, for haemopoietic cells, has been developed using bone marrow cells alone, or co-cultures of thymus and bone marrow cells, inoculated into four ounce medical bottles. After several days growth, such cultures consisted of an attaching population of cells, forming discrete colonies, and a non-attaching population. In the (co-cultures) there was a 2 X enhancement of monolayer colony development compared with the combined total present in the (marrow alone) plus (thymus alone) cultures. Also, better maintenance of non-attaching cells was seen in the (co-cultures). Normal CFUS and CFUC were present in both the (marrow alone) and the (co-cultures) for at least 14 days.In the (marrow alone) cultures, granulocytes in all stages of development were present for the first week, but by 12 days the culture consisted mainly of mono-nuclear cells. In the (co-cultures), however, at 12 days more than 60% of the cells were granulocytes, in all stages of differentiation. (Co-cultures) established using lethally irradiated thymus cells were not able to support this prolonged myeloid differentiation.By feeding the (co-cultures) it was possible to maintain production of (granulocytic) cells for at least ten weeks, although no fully mature granulocytes were observed. After the second feeding, no CFUS were detectable, but variable numbers of agar colony forming cells (not classical CFUC) were present at least for ten weeks.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 111 (1982), S. 177-186 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have isolated continuously growing cell lines derived from mouse bone marrow stroma. These cell lines were independently obtained, and though they showed morphologies ranging from the epithelioid to the fibroblastoid patterns, they all differentiated into adipocytes. Subclones obtained from two cell lines had a very high frequency (90-100%) of differentiation into adipocytes after two or three weeks of arrested growth. Though extensive accumulation of lipid often mechanically impaired mitosis, the cells committed to adipocytes did not suffer an irreversible loss of proliferative capacity. Adipogenesis was obtained in conditions similar to those required for fat cell formation in long-term bone marrow culture. The cell lines were found to be insensitive to insulin as a signal of adipocyte differentiation. The ultrastructural characteristics of the preadipocytes and fat cells are also similar to those of the fat cells developing in long-term bone marrow culture. As such, these cell lines should prove useful for analysing cell/cell interactions in haemopoiesis.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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