Revertant mutation released a lethal mutation concealed in a healthy parent: A previously unreported pathogenesis of hereditary disorders

2016 ◽  
Vol 84 (1) ◽  
pp. e46
Author(s):  
Yasushi Ogawa ◽  
Takuya Takeichi ◽  
Michihiro Kono ◽  
Nobuyuki Hamajima ◽  
Toshimichi Yamamoto ◽  
...  
1979 ◽  
Vol 42 (02) ◽  
pp. 694-704 ◽  
Author(s):  
F Rendu ◽  
A T Nurden ◽  
M Lebret ◽  
J P Caen

SummaryWe have used the mepacrine-labelling procedure to measure the dense body (serotonin storage organelle) content of the platelets of 2 hereditary disorders where abnormalities in dense body number were suspected. The platelets were incubated with mepacrine and examined by fluorescence microscopy. A mean number of 5.4 ± 0.8 (SD) dense bodies per platelet was calculated from the data obtained using platelets isolated from 40 normal human subjects. In contrast the platelets of 2 patients with the Bernard-Soulier syndrome contained an average of 14 and 17 labelled granules. This increase was associated with a much greater capacity of the platelets to accumulate 14C-5-HT. The opposite result was obtained using the platelets from 2 patients with the Hermansky-Pudlak syndrome which contained few granules labelled by mepacrine and took up less 14C-5-HT than normal human platelets. Centrifugation of the patients’ platelets on discontinuous sucrose gradients showed that the platelets of the 2 Bemard-Soulier patients were much denser than normal whereas a high proportion of low density platelets was observed in the Hermansky-Pudlak syndrome. These results further define the platelet abnormalities in the two syndromes and suggest that dense body number may be one of the factors governing platelet density.


2019 ◽  
Vol 20 (10) ◽  
pp. 1008-1017 ◽  
Author(s):  
Vandita Kakkar ◽  
Manoj Kumar Verma ◽  
Komal Saini ◽  
Indu Pal Kaur

Oral Cancer (OC) is a serious and growing problem which constitutes a huge burden on people in more and less economically developed countries alike. The scenario is clearly depicted from the increase in the expected number of new cases in the US diagnosed with OC from 49,670 people in 2016, to 49,750 cases in 2017. The situation is even more alarming in India, with 75,000 to 80,000 new cases being reported every year, thus making it the OC capital of the world. Leukoplakia, erythroplakia, oral lichen planus, oral submucous fibrosis, discoid lupus erythmatosus, hereditary disorders such as dyskeratosis congenital and epidermolisys bullosa are highlighted by WHO expert working group as the predisposing factors increasing the risk of OC. Consumption of tobacco and alcohol, genetic factors, and human papilloma virus are assigned as the factors contributing to the aetiology of OC. On the other hand, pathogenesis of OC involves not only apoptosis but also pain, inflammation and oxidative stress. Inspite of current treatment options (surgery, radiotherapy, and chemotherapy), OC is often associated with recurrence and formation of secondary primary tumours resulting in poor overall survival rates (∼50%). The intervention of nano technology-based drug delivery systems as therapeutics for cancers is often viewed as a cutting edge for technologists. Though ample literature on the usefulness of nano-coutured cancer therapeutics, rarely any product is in pipeline. Yet, despite all the hype about nanotechnology, there are few ongoing trials. This review discusses the current and future trends of nano-based drug delivery for the treatment of OC.


1927 ◽  
Vol 61 (677) ◽  
pp. 520-530 ◽  
Author(s):  
R. A. Brink
Keyword(s):  

1956 ◽  
Vol 54 (2) ◽  
pp. 219-235 ◽  
Author(s):  
Walter Landauer
Keyword(s):  

Genetics ◽  
1979 ◽  
Vol 92 (1) ◽  
pp. 151-160
Author(s):  
H Traut

ABSTRACT When females of Drosophila melanogaster are treated with chemical or physical mutagens, not only in one but also in both of the two homologous X chromosomes of a given oocyte, a recessive sex-linked lethal mutation may be induced. A method is described that discriminates between such "single" and "double mutations." A theory is developed to show how a comparison between the expected and the observed frequency of double mutations yields an indication of the intercellular distribution (random or nonrandom) of recessive lethal mutations induced by mutagenic agents in oocytes and, consequently, of the distribution (homogeneous or nonhomogeneous) of those agents.—Three agents were tested: FUdR (12.5, 50.0 and 81.0,μg/ml), mitomycin C (130.0 μg/ml) and X rays (2000 R, 150 kV). After FUdR feeding, no increase in the mutation frequency usually observed in D. melanogaster without mutagenic treatment was obtained (u=0.13%, namely three single mutations among 2332 chromosomes tested). After mitomycin C feeding, 104. single and three double mutations were obtained. All of the 50 mutations observed after X irradiation were single mutations. The results obtained in the mitomycin C and radiation experiments favor the assumption of a random intercellular distribution of recessive lethal mutations induced by these two agents in oocytes of D. melanogaster. Reasons are discussed why for other types of mutagenic agents nonrandom distributions may be observed with our technique.


1992 ◽  
Vol 267 (34) ◽  
pp. 24625-24633
Author(s):  
A.H. West ◽  
D.J. Clark ◽  
J Martin ◽  
W Neupert ◽  
F.U. Hartl ◽  
...  

Genetics ◽  
1982 ◽  
Vol 101 (3-4) ◽  
pp. 461-476
Author(s):  
Todd R Laverty ◽  
J K Lim

ABSTRACT In this study, we show that at least one lethal mutation at the 3F-4A region of the X chromosome can generate an array of chromosome rearrangements, all with one chromosome break in the 3F-4A region. The mutation at 3F-4A (secondary mutation) was detected in an X chromosome carrying a reverse mutation of an unstable lethal mutation, which was mapped in the 6F1-2 doublet (primary mutation). The primary lethal mutation at 6F1-2 had occurred in an unstable chromosome (Uc) described previously (Lim 1979). Prior to reversion, the 6F1-2 mutation had generated an array of chromosome rearrangements, all having one break in the 6F1-2 doublet (Lim 1979, 1980). In the X chromosomes carrying the 3F-4A secondary lethal mutation the 6F1-2 doublet was normal and stable, as was the 3F-4A region in the X chromosome carrying the primary lethal mutation. The disappearance of the instability having a set of genetic properties at one region (6F1-2) accompanied by its appearance elsewhere in the chromosome (3F-4A) implies that a transposition of the destabilizing element took place. The mutant at 3F-4A and other secondary mutants exhibited all but one (reinversion of an inversion to the normal sequence) of the eight properties of the primary lethal mutations. These observations support the view that a transposable destabilizing element is responsible for the hypermutability observed in the unstable chromosome and its derivaties.


1970 ◽  
Vol 61 (5) ◽  
pp. 219-220 ◽  
Author(s):  
KATHARINE P. HUMMEL
Keyword(s):  

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