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  • 2000-2004  (6)
  • 1985-1989  (25)
  • 1980-1984  (9)
  • 1975-1979  (8)
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 96 (1989), S. 0 
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary. Sera from 13 pregnant women carrying a fetus with a neural tube defect, and from 13 control women with normal pregnancies at the same stage of gestation were used in the culture of postimplantation rat embryos. Serum from women with normal pregnancies had no adverse effect on rat embryo growth and development. Serum from 10 of the women with affected fetuses had a deleterious effect on the rat embryos as abnormalities of neural tube closure were observed in 28% of the conceptuses compared to only 1·3% of the embryos cultured in control scrum.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 27 (2004), S. 0 
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Phyllotaxis, the arrangement of leaves around a stem, shows in the vast majority of cases a regularity in the divergence angle of subsequent leaves which divide the whole circle into regular fractions. These are in most cases rational fractions of two Fibonacci numbers in an alternating series, converging towards the irrational limit of the golden section, corresponding to the golden divergence angle of 137.5  . . . degrees. This peculiarity was a long-standing mystery. Here, it is related to the evolutionary pressure of optimal light capture for maximal photosynthetic activity. A model is established which relates minimal shadowing for the lower leaves to the divergence angle. Numerical results of this model agree well with semi-empirical data on the dependence of light capture from the divergence angle. The basic shadow function of the model is also related with the demand of minimal shadowing for the angular separation of leaves and obtain, using elementary number theory, as solution the golden section. Further numerical studies show that the rational approach to the golden section (Schimper–Braun series) is related to the leaf width and the number of leaves of the plant.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of oral pathology & medicine 17 (1988), S. 0 
    ISSN: 1600-0714
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The purpose of this study was to determine whether the mucosal alterations of the dorsal rat tongue produced by Candida albicans infection were reversible upon treatment with the antifungal drug ketoconazole. Following experimentally-produced infection, 17 rats showed clinical evidence of persistent lesions over a period of 20 weeks. Eight of these animals were then treated with ketoconazole daily for 2 weeks (20 mg/kg/day). Appropriate non-infected controls and ketoconazole-only controls were also maintained. Five weeks after the ketoconazole treatment, all animals were killed and the dorsal tongues evaluated clinically and histologically. Control groups showed no abnormalities. Of the 8 animals in the treated-lesion group, all showed lesional resolution, while only 2 of the 9 animals in the untreated-lesion group showed resolution of their lesions (p=0.002). These findings indicate that the epithelial changes produced by this candidal isolate for this period of time are reversible.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1600-0714
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background:  In contrast to the immunosupressed patient population, the prevalence of fluconazole-resistant strains of Candida albicans among healthy individuals has not been extensively studied.Methods:  Candida species were cultured form 50 healthy outpatients with clinical signs of oral candidiasis. Following one week of the recommended fluconazole regimen, post-treatment cultures were obtained. Both pre- and post-treatment yeasts were identified and in vitro susceptibility testing was performed using the NCCLS M-27A method. Strains were further differentiated using established cDNA probes.Results:  Forty-four patients (88%) had positive C.albicans cultures prior to treatment. Antifungal susceptibility testing of these strains demonstrated no in vitro resistance to fluconazole. At post-treatment evaluation, eight patients (18%) had persistent signs of infection and 10 patients (23%) had positive Candida sp. cultures despite no clinical signs of infection. DNA analysis confirmed that the same C. albicans strain was present both in the pre-treatment and the post-treatment cultures.Conclusions:  Our results showed that the presence of fluconazole-resistant strains of C.albicans does not appear to be prevalent among healthy outpatients furthermore, in vitro antifungal susceptibility testing does not always predict successful therapy in these patients.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of oral pathology & medicine 16 (1987), S. 0 
    ISSN: 1600-0714
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In order to examine the behavior of Candida albicans in an oral mucosal model, 16 isolates of the organism were collected from a variety of clinical settings and were inoculated weekly, in equal numbers and concentrations, into the mouths of separate groups of 20 female Sprague-Dawley rats. Oral swabs were taken bi-weekly in order to monitor the presence of the yeast. After 16 weeks, the animals were killed and the tongues were examined grossly and histologically. Six isolates demonstrated the ability to produce characteristic dorsal tongue lesions to varying degrees (1/20; 1/20; 1/20; 2/20; 3/20; and 12/20). Of the remaining 10 isolates, 5 showed hyphal penetration of the keratin layer of the dorsal tongue epithelium, yet no mucosal reaction was elicited and no lesion was produced (1/19; 2/19; 4/20; 5/20 and 5/20). These findings support the concept that C. albicans exhibits a spectrum of mucosal pathogenicity for dorsal rat tongue.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-2013
    Keywords: Electron microprobe analysis ; Volume expansion ; Intracellular electrolytes ; Renal tubular cells ; Natriuretic mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract It has previously been shown that during mannitol-saline volume expansion (VE) Na transport was inhibited 50% by harvested proximal tubular fluid without a change in paracellular shunt pathway permeability to Na. To determine whether this inhibition was due to changes in cellular entry step or an effect on the pump itself, intracellular element concentrations were measured by electron microprobe X-ray ranalysis in proximal tubular cells of control (non-expanded, NE) and VE rats. Na i , Cl i and phosphorus i were increased (mean±S.E.) from 19.3±0.8 to 23.4±0.6, 15.8±0.4 to 21.3±0.4 and 124.3±2.6 to 138.0±1.8 mmol · kg−1 wet weight (P〈0.001) respectively while K i remained unchanged: 122.9±2.2 and 124.2±1.3 mmol · kg−1 wet weight. The increases in Na i and Cl i were in excess of cell shrinkage produced by the hyperosmolal peritubular environment while the unchanged K i in the face of cell shrinkage indicates and actual loss. It is concluded that mannitol-saline VE inhibits the Na pump producing a rise in Na i and a fall in K i .
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-2013
    Keywords: Electron microprobe analysis ; Sympathetic neurones ; Cellular electrolyte concentrations ; Carbachol ; Ouabain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Intracellular element concentrations were measured in rat sympathetic neurones using energy dispersive electron microprobe analysis. The resting intracellular concentrations of sodium potassium and chloride measured in ganglia maintained for about 90 min in vitro at 25° C were 3, 155 and 25 mmol/kg total tissue wet weight respectively. Recalculated in mmol/l cell water, these values are 5, 196 and 32 respectively. There were no significant differences between the nuclear and cytoplasmic values of these ions. Incubation in either carbachol (108 μmol/l, 4 min) or ouabain (1 mmol/l, 60 min) significantly increased the intracellular sodium and decreased the intracellular potassium concentrations. Neither substance materially altered the intracellular chloride concentration. The data obtained are compared and contrasted to those obtained in mammalian sympathetic neurones using chemical analysis and ion-sensitive microelectrodes.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-2013
    Keywords: Acute metabolic acidosis ; Renal distal electrolyte transport ; Renal cell electrolyte concentrations ; Individual distal tubule cells ; Transmembrane electrolyte concentration gradients ; Electron microprobe analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We studied the effect of acute metabolic acidosis on potassium, sodium and chloride gradients across the apical membrane of proximal and distal tubule cells by determining electrolyte concentrations in individual cells and in tubule fluid employing electron microprobe analysis. Cellular measurements were performed on freeze-dried cryosections of the renal cortex, analysis of tubule fluid electrolyte concentrations on freeze-dried microdroplets of micropuncture samples obtained from proximal and from early and late distal collection sites. Acidosis (NH4Cl i.v. and i.g.) induced a substantial rise in plasma potassium concentration without significant effects on cell potassium concentrations. Potassium concentrations along the surface distal tubule were also unaltered; thus the chemical driving force for potassium exit from cell to lumen was not affected by acidosis. In all but intercalated cells acidosis markedly increased cell phosphorus concentration and cell dry weight indicating cell shrinkage and thus diminution of cell potassium content. Because the increase in intracellular chloride concentration exceeded the increase in plasma chloride concentration, the chemical chloride gradient across the contraluminal membrane was markedly depressed by acidosis.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 66 (1988), S. 843-848 
    ISSN: 1432-1440
    Keywords: Renal papillary cells ; Cell electrolytes ; Osmoadaptation ; Organic osmolytes ; Electron microprobe analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cells of the renal papilla are subject to extreme variations in extracellular tonicity. To obtain more insight into the mechanisms whereby these cells adapt osmotically to these unique environmental conditions, elements were measured in individual cells of the rat renal papilla in antidiuresis and after prolonged furosemide administration. In antidiuresis cell sodium, chloride and potassium concentrations did not differ fundamentally from those observed in tubule cells exposed to isotonic surroundings such as in proximal tubule cells. The marked fall in extracellular electrolyte concentrations induced by furosemide was paralleled by a far less pronounced decline in intracellular sodium, chloride and potassium concentrations. These data indicate that papillary cells achieve osmoadaptation to widely differing extracellular tonicities mainly by varying the intracellular concentrations of osmotically active substances other than inorganic electrolytes. Since high concentrations of organic osmolytes (sorbitol, inositol, glycerophosphorylcholine and other trimethylamines) have been detected in the papilla and since the tissue contents of these compounds have been shown to vary in parallel with urine osmolality, it may be concluded that metabolically inert, organic osmolytes play a dominant role in the osmoregulation of renal papillary cells.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 57 (1979), S. 993-999 
    ISSN: 1432-1440
    Keywords: Electron microprobe analysis ; Intracellular electrolytes ; Kidney ; Ischaemia ; Elektronenstrahl-Mikroanalyse ; Intrazelluläre Elektrolyte ; Niere ; Ischämie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to be able to examine the processes involved in transepithelial transport in tissues, which are not composed of a single cell type, methods are required, which permit analysis at a cellular level. The technique of electron microprobe analysis permits the intracellular concentrations of many elements to be determined simultaneously in various portions of the cell. The application of this method to renal cortical tissue has shown that the best estimates of the cytoplasmic concentrations are to be obtained in regions close to the nucleus, farthest from the basolateral infoldings and microvilli, which separate the intracellular environment from the extracellular space. The nuclear concentrations of Na and K do not differ from those in the surrounding cytoplasm, although those of P and C1 are somewhat higher in cytoplasm. The intracellular element concentrations in the different cell types vary somewhat, proximal tubular cells contain higher concentrations of Na and C1 and lower ones of P than distal tubular cells. Following ischaemia, a manoeuvre know to result in a disturbance of intracellular electrolytes, Na was observed to rise and K to fall only in the non-surface cells of kidneys exposed to the air, but in all cells, if the kidneys were kept air-free in an atmosphere of N2. The proximal and distal tubular cells showed a variable resistance to ischaemia, the distal tubular cells being much more resistant. Despite the severity of the electrolyte disturbance following ischaemia, the intracellular composition was completely restored one hour after re-introducing renal blood flow.
    Type of Medium: Electronic Resource
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