scholarly journals Leo Sachs. 14 October 1924—12 December 2013

2019 ◽  
Vol 66 ◽  
pp. 355-375
Author(s):  
Yoram Groner ◽  
Pnina Sachs ◽  
Joseph Lotem
Keyword(s):  
Surface Membrane ◽  
Blood Group Antigens ◽  
X Rays ◽  
Major Mechanism ◽  
Leukaemic Cells ◽  
Clonal Development ◽  
Membrane Changes ◽  
Differential Responsiveness ◽  
Defects Identification

Leo Sachs was a worldwide renowned scientist for his major contributions in several fields. In the mid 1950s he showed that amniocentesis could be used for prenatal diagnosis of sex and blood group antigens. He then focused on various aspects of normal development and cancer, including the control of normal haematopoiesis and leukaemia, carcinogenesis in vitro by polyoma and SV40 tumour viruses, chemical carcinogens and X-rays, chromosomes and the reversibility of cancer, surface membrane changes in malignant cells and suppression of malignancy by inducing differentiation. The cell culture system he established in the early 1960s for the clonal development of normal haematopoietic cells made it possible to analyse the molecular basis of normal haematopoiesis, and discover the proteins that regulate viability, proliferation and differentiation of different blood cell lineages and the changes that drive leukaemia. His studies established significant general concepts, including: the differential responsiveness of cancer cells to normal regulators of development; suppression of myeloid leukaemia by inducing differentiation, bypassing malignancy-driving genetic defects; identification of chromosomes that control tumour suppression; discovering apoptosis as a major mechanism by which WT-p53 suppresses malignancy; and the ability of haematopoietic cytokines to suppress apoptosis in both normal and leukaemic cells. Leo was fortunate to witness his pioneering discoveries and ideas move from the basic science stage to effective clinical applications, using amniocentesis for prenatal detection of genetic abnormalities, augmenting normal haematopoiesis in patients with various haematopoietic deficiencies and suppressing malignancy by inducing differentiation and apoptosis.

scholarly journals Radiosensitization of Prostate Cancers In Vitro and In Vivo to Erbium-filtered Orthovoltage X-rays Using Actively Targeted Gold Nanoparticles

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Allison M. Khoo ◽  
Sang Hyun Cho ◽  
Francisco J. Reynoso ◽  
Maureen Aliru ◽  
Kathryn Aziz ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
X Rays ◽  
Prostate Cancers

scholarly journals Optimization of X-ray Investigations in Dentistry Using Optical Coherence Tomography

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4554
Author(s):  
Ralph-Alexandru Erdelyi ◽  
Virgil-Florin Duma ◽  
Cosmin Sinescu ◽  
George Mihai Dobre ◽  
Adrian Bradu ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Radiation Dose ◽  
Imaging Techniques ◽  
Image Resolution ◽  
Optical Coherence ◽  
X Rays ◽  
High Quality ◽  
X Ray

The most common imaging technique for dental diagnoses and treatment monitoring is X-ray imaging, which evolved from the first intraoral radiographs to high-quality three-dimensional (3D) Cone Beam Computed Tomography (CBCT). Other imaging techniques have shown potential, such as Optical Coherence Tomography (OCT). We have recently reported on the boundaries of these two types of techniques, regarding. the dental fields where each one is more appropriate or where they should be both used. The aim of the present study is to explore the unique capabilities of the OCT technique to optimize X-ray units imaging (i.e., in terms of image resolution, radiation dose, or contrast). Two types of commercially available and widely used X-ray units are considered. To adjust their parameters, a protocol is developed to employ OCT images of dental conditions that are documented on high (i.e., less than 10 μm) resolution OCT images (both B-scans/cross sections and 3D reconstructions) but are hardly identified on the 200 to 75 μm resolution panoramic or CBCT radiographs. The optimized calibration of the X-ray unit includes choosing appropriate values for the anode voltage and current intensity of the X-ray tube, as well as the patient’s positioning, in order to reach the highest possible X-rays resolution at a radiation dose that is safe for the patient. The optimization protocol is developed in vitro on OCT images of extracted teeth and is further applied in vivo for each type of dental investigation. Optimized radiographic results are compared with un-optimized previously performed radiographs. Also, we show that OCT can permit a rigorous comparison between two (types of) X-ray units. In conclusion, high-quality dental images are possible using low radiation doses if an optimized protocol, developed using OCT, is applied for each type of dental investigation. Also, there are situations when the X-ray technology has drawbacks for dental diagnosis or treatment assessment. In such situations, OCT proves capable to provide qualitative images.

scholarly journals Crocetin Mitigates Irradiation Injury in an In Vitro Model of the Pubertal Testis: Focus on Biological Effects and Molecular Mechanisms

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1676
Author(s):  
Giulia Rossi ◽  
Martina Placidi ◽  
Chiara Castellini ◽  
Francesco Rea ◽  
Settimio D'Andrea ◽  
...  
Keyword(s):  
In Vitro Model ◽  
Molecular Mechanisms ◽  
Biological Effects ◽  
Cellular Damage ◽  
X Rays ◽  
Adolescent Cancer ◽  
Radiation Induced ◽  
Vitro Model ◽  
Underlying Mechanisms

Infertility is a potential side effect of radiotherapy and significantly affects the quality of life for adolescent cancer survivors. Very few studies have addressed in pubertal models the mechanistic events that could be targeted to provide protection from gonadotoxicity and data on potential radioprotective treatments in this peculiar period of life are elusive. In this study, we utilized an in vitro model of the mouse pubertal testis to investigate the efficacy of crocetin to counteract ionizing radiation (IR)-induced injury and potential underlying mechanisms. Present experiments provide evidence that exposure of testis fragments from pubertal mice to 2 Gy X-rays induced extensive structural and cellular damage associated with overexpression of PARP1, PCNA, SOD2 and HuR and decreased levels of SIRT1 and catalase. A twenty-four hr exposure to 50 μM crocetin pre- and post-IR significantly reduced testis injury and modulated the response to DNA damage and oxidative stress. Nevertheless, crocetin treatment did not counteract the radiation-induced changes in the expression of SIRT1, p62 and LC3II. These results increase the knowledge of mechanisms underlying radiation damage in pubertal testis and establish the use of crocetin as a fertoprotective agent against IR deleterious effects in pubertal period.

Schistosoma mansoni: a comparative study of artificially transformed schistosomula and schistomula recoverd after cercarial penetration of isolated skin

Parasitology ◽  
1977 ◽  
Vol 74 (1) ◽  
pp. 73-86 ◽  
Author(s):  
Linda H. Brink ◽  
Diane J. McLaren ◽  
S. R. Smithers
Keyword(s):  
Comparative Study ◽  
Schistosoma Mansoni ◽  
Amorphous Material ◽  
Surface Membrane ◽  
Antigenic Determinants ◽  
Agglutination Reaction ◽  
Rat Serum ◽  
Mechanical Separation ◽  
B Blood Group

A comparison was made of the ultrastructure, development and antigenic nature of the surfaces and of the viability of three types of schistosomula of Schistosoma mansoni: schistosomula formed afrer cercariae had penetrated isolated skin (SS), schistosomula produced after mechanical separation of cercarial tails from bodies (MS), and schistosomula transformed from cercariae after incubation in fresh rat serum (RS).Within 2 h of transformation, the surface membrane of all three types of schistosomula had changed from trilaminate to heptalaminate structures and SS and MS had lost their cercarial glycocalyx. Initially a dense amorphous material was demonstrated on the surfaces of RS, which was thought to be the result of an interaction between a factor in rat serum and the glycocalyx: this material was greatly reduced within 2 h of transformation. The pre-acetabular glands of SS were emptied while those of MS and RS retained their contents. Immunofluorescent studies showed that all schistosomula bound serum from mice immune to S. mansoni, but the binding was stronger with MS and RS. The mixed agglutination reaction demonstrated the presence of human A and B blood group-like antigenic determinants on approximately 30% of 3 h old SS; these determinants were not detected on MS or RS. In vitro, the development of MS and RS was similar to SS; the first schistosomula reached the ‘gut-closed’ stage by day 10; 50–70% of SS reached this stage by day 12, in contrast to only 25–50% of MS and RS. Between 28 and 45% of all schistosomula developed to maturity when injected intravenously into mice.It was concluded that the two types of artificially prepared schistosomula fultil the main criteria of transformation from cercaria to schistosomulum. Further, it is suggested that MS are the most appropriate source of material for immunochemical and physiological studies.

Effect of guaianolides in the meiosis reinitiation of amphibian oocytes

Zygote ◽  
2016 ◽  
Vol 25 (1) ◽  
pp. 10-16 ◽  
Author(s):  
J. Zapata-Martínez ◽  
G. Sánchez-Toranzo ◽  
F. Chaín ◽  
C.A.N. Catalán ◽  
M.I. Bühler
Keyword(s):  
Biological Activities ◽  
Wide Spectrum ◽  
Sesquiterpene Lactones ◽  
Inhibitory Effect ◽  
Biological Molecules ◽  
Plant Metabolites ◽  
Major Mechanism ◽  
Bufo Arenarum ◽  
Asteraceae Family

SummarySesquiterpene lactones (STLs) are a large and structurally diverse group of plant metabolites generally found in the Asteraceae family. STLs exhibit a wide spectrum of biological activities and it is generally accepted that their major mechanism of action is the alkylation of the thiol groups of biological molecules. The guaianolides is one of various groups of STLs. Anti-tumour and anti-migraine effects, an allergenic agent, an inhibitor of smooth muscle cells and of meristematic cell proliferation are only a few of the most commonly reported activities of STLs. In amphibians, fully grown ovarian oocytes are arrested at the beginning of meiosis I. Under stimulus with progesterone, this meiotic arrest is released and meiosis progresses to metaphase II, a process known as oocyte maturation. There are previous records of the inhibitory effect of dehydroleucodin (DhL), a guaianolide lactone, on the progression of meiosis. It has been also shown that DhL and its 11,13-dihydroderivative (2H-DhL; a mixture of epimers at C-11) act as blockers of the resumption of meiosis in fully grown ovarian oocytes from the amphibian Rhinella arenarum (formerly classified as Bufo arenarum). The aim of this study was to analyze the effect of four closely related guaianolides, i.e., DhL, achillin, desacetoxymatricarin and estafietin as possible inhibitors of meiosis in oocytes of amphibians in vitro and discuss some structure–activity relationships. It was found that the inhibitory effect on meiosis resumption is greater when the lactone has two potentially reactive centres, either a α,β–α′,β′-diunsaturated cyclopentanone moiety or an epoxide group plus an exo-methylene-γ-lactone function.

Interaction of normal haemopoiesis and L5222 leukaemic cells in vivo and in vitro

1977 ◽  
Vol 1 (2-3) ◽  
pp. 145-147 ◽  
Author(s):  
D. Hoelzer ◽  
E.B. Harriss ◽  
E. Kurrle
Keyword(s):  
Leukaemic Cells
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