Summary.-The growth of tumours in guinea-pigs was observed for 20 weeks after placing them on various doses of vitamin C.Complete tumour regression occurred in 55% of those animals receiving 0-3 mg/kg/day ascorbic acid, whereas animals given 10 mg/kg/day showed tumour inhibition but no regression. In contrast, tumours in animals maintained on 1 g/kg/day ascorbic acid grew without sign of retardation. When increased amounts of ascorbic acid were restored to the diet of scorbutic tumour-bearing animals, tumours which had not regressed responded with enhanced growth. Likewise, animals previously maintained on 10 mg/kg ascorbic acid responded in turn to the additional vitamin with enhanced tumour growth. In contrast, all tumour-bearing animals maintained on 1 g/kg ascorbic acid died within 3 weeks when this dose was replaced with 0-3 mg/kg.
Verrucous carcinoma of the bladder unassociated with bilharzial cystitis is an exceedingly rare entity, with only 3 cases reported in the literature. We describe a patient and review the literature concerning verrucous carcinoma.
Summary. One melanized (Mc3) and one non‐melanized (Mc3W) multicellular form mutant of W. dermatitidis were compared with parental wild type in NYLAR mice. Each mutant grows as multicellular (muriform‐like) forms in vitro at 37 °C and as yeasts at ≤ 30 °C. Yeast cells of all three strains were injected intravenously at concentrations of 1 times 104, 1 times 106, 1 times 107, 3 times 107 and 1 times 108 cells/mouse in groups of 10 mice. There was no virulence difference between wild type and Mc3, with 100% mortality obtained with each strain at ≥1 times 107 cells/mouse. In contrast, Mc3W was less virulent, with mortality being obtained only at 1 times 108 cells/mouse. Histopathological study of brains, lungs, livers and spleens of moribund mice revealed that both Mc3 and Mc3W persisted in tissue as muriform cells, and in some cases as yeast, pseudohyphal and hyphal forms. There was no major difference between Mc3 and Mc3W in terms of histopathological response. These data support the association between melanin and virulence in W. dermatitidis and provide a model for the study of muriform cells in vivo.
Zusammenfassung. Eine Melanin‐bildende (Mc3) und eine nicht Melanin‐bildende (Mc3W) multizellulare Mutante von Wangiella dermatitidis wurde mit dem Elter‐Wildstamm in NYLAR‐Mausen gepruft. Jede Mutante wächst als multizellulare Form in vitro bei 37°C und als Hefeform bei ≥ 30°C. Hefezellen aller drei Stämme wurden intravenös in Konzentrationen von 1 × 104, 1 × 106, 1 × 107, 3 × 107 und 1 × 108 Zellen pro Maus in Gruppen von je 10 Mausen injiziert. Zwischen dem Wildtyp und dem Mc3‐Typ wurden bei 100%iger Mortalitat mit dem Inokulum von ≥ 1 × 107 Zellen pro Maus keine Virulenzun‐terschiede beobachtet. Der Mc3W‐Stamm hinge‐gen erwies sich mit Mortalitat nur bei 1 × 108 Zellen pro Maus als weniger virulent. Histopathologische Untersuchungen von Gehirn, Lunge, Leber und Milz moribunder Mäuse zeigten, daβ sowohl Mc3 wie Mc3W im Gewebe als muriforme Zellen persistierten, in einigen Fallen auch als Hefe‐, Pseudohyphen‐ und Hyphenphase. In der Gewebsreaktion waren zwischen Mc3 und Mc3W keine wesentlichen Unterschiede zu erkennen, Die Befunde stutzen den Zusammenhang zwischen Melaninbildung und Virulenz bei Wangiella dermatitidis und stellen ein Modell zum Stu‐dium muriformer Zellen in vivo dar.
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