scholarly journals Do we miss half of the injuries sustained during rape because we cannot see them? An overview of the use of toluidine blue tissue stain in the medical assessment of rape cases

2018 ◽  
Vol 60 (2) ◽  
pp. 37-40 ◽  
Author(s):  
J. M. Kotzé ◽  
H. Brits
Keyword(s):  
Toluidine Blue ◽  
External Genitalia ◽  
Walk Away ◽  
Medical Assessment ◽  
Legal Evidence ◽  
High Affinity ◽  
False Allegation ◽  
Dna And Rna ◽  
Legal Testimony ◽  
Blue Stain

The prosecution of rape cases is difficult due to the absence of eyewitnesses. McCauley found that the detection of vaginal lacerations increased from one in 24 to 14 in 24 in reported adult rape cases when toluidine blue was used. Proof of injuries consistent with sexual penetration adds significantly to the evidentiary value of the medico-legal testimony. Although rape is not a clinical diagnosis and there are no diagnostic criteria to confirm rape, the possibility of genital injury during rape far exceeds the possibility of injury with consensual intercourse. If a complete examination, including the use of toluidine blue, is not used a rapist may walk away to rape again, while the victims remain with the stigma that they may have made a false allegation. Toluidine blue is a basic thiazine metachromatic dye. It has a high affinity for acidic tissue components, thereby staining tissues rich in DNA and RNA. The epithelium of the external genitalia does not have nucleated cells and prevents contact of stain with nuclei. Where the epithelium is damaged and the underlying nucleated cells are exposed, the nuclei stain blue. Injuries sustained during genital penetration show a distinctive distribution.Toluidine blue stain is easy and safe to use, available, inexpensive and does not interfere with other medico-legal evidence, therefore it is recommended to be used in the examination of all cases of alleged rape.

scholarly journals RNA binding to human METTL3-METTL14 restricts N6-deoxyadenosine methylation of DNA in vitro

2022 ◽  
Author(s):  
Shan Qi ◽  
Javier Mota ◽  
Siu-Hong Chan ◽  
Johanna Villarreal ◽  
Nan Dai ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Rna Binding ◽  
Methyl Group ◽  
High Affinity ◽  
Methylation Of Dna ◽  
Dna And Rna ◽  
Close Proximity ◽  
Methylation Activity

Methyltransferase like-3 (METTL3) and METTL14 complex transfers a methyl group from S-adenosyl-L-methionine to N6 amino group of adenosine bases in RNA (m6A) and DNA (m6dA). Emerging evidence highlights a role of METTL3-METTL14 in the chromatin context, especially in processes where DNA and RNA are held in close proximity. However, a mechanistic framework about specificity for substrate RNA/DNA and their interrelationship remain unclear. By systematically studying methylation activity and binding affinity to a number of DNA and RNA oligos with different propensities to form inter- or intra-molecular duplexes or single-stranded molecules in vitro, we uncover an inverse relationship for substrate binding and methylation and show that METTL3-METTL14 preferentially catalyzes the formation of m6dA in single-stranded DNA (ssDNA), despite weaker binding affinity to DNA. In contrast, it binds structured RNAs with high affinity, but methylates the target adenosine in RNA (m6A) much less efficiently than it does in ssDNA. We also show that METTL3-METTL14-mediated methylation of DNA is largely restricted by structured RNA elements prevalent in long noncoding and other cellular RNAs.

scholarly journals G-Quadruplex-Based Drug Delivery Systems for Cancer Therapy

2021 ◽  
Vol 14 (7) ◽  
pp. 671
Author(s):  
Jéssica Lopes-Nunes ◽  
Paula Oliveira ◽  
Carla Cruz
Keyword(s):  
Drug Delivery ◽  
Small Molecules ◽  
Drug Delivery Systems ◽  
Delivery Systems ◽  
Nano Particles ◽  
Future Research ◽  
High Affinity ◽  
Dna And Rna ◽  
G Quadruplex ◽  
Gold Nano Particles

G-quadruplexes (G4s) are a class of nucleic acids (DNA and RNA) with single-stranded G-rich sequences. Owing to the selectivity of some G4s, they are emerging as targeting agents to overtake side effects of several potential anticancer drugs, and delivery systems of small molecules to malignant cells, through their high affinity or complementarity to specific targets. Moreover, different systems are being used to improve their potential, such as gold nano-particles or liposomes. Thus, the present review provides relevant data about the different studies with G4s as drug delivery systems and the challenges that must be overcome in the future research.

scholarly journals STUDIES ON NUCLEIC ACID METACHROMASY

1965 ◽  
Vol 27 (2) ◽  
pp. 327-336 ◽  
Author(s):  
Ned Feder ◽  
Merrill K. Wolf
Keyword(s):  
Nucleic Acid ◽  
Ribosomal Rna ◽  
Toluidine Blue ◽  
Color Contrast ◽  
Tissue Sections ◽  
Dna And Rna ◽  
Excellent Preservation ◽  
Structural Preservation ◽  
Intense Color

Acrolein-fixed, polyester wax-embedded tissue sections showed excellent preservation of light microscopic architecture and, when stained with toluidine blue, intense color contrast between DNA, which stained orthochromatically, and RNA, which stained metachromatically. This method has practical value for differentiating DNA from RNA in the same section. The color contrast was impaired by substituting formaldehyde for acrolein or paraffin for polyester wax, and was negligible in tissues fixed in formaldehyde or Carnoy's fluid and embedded in paraffin. Quality of structural preservation paralleled degree of color contrast. Metachromatic staining can be analysed, by the quantitative parameters of Bradley and colleagues, to provide inferences regarding the conformation of biopolymers in tissue sections. Comparison of the nucleic acid color contrasts in toluidine blue-stained sections with titrations of fixative-treated nucleic acids against toluidine blue in solution indicated a greater difference in conformation between DNA- and RNA-protein in acrolein-polyester sections than between acrolein-treated free DNA and RNA in solution. This is supported by recent evidence that the conformation of ribosomal RNA is quite different in whole ribosomes from that assumed by the same RNA free in solution. The acrolein-polyester method may enhance color contrast by providing superior preservation of ordered nucleoprotein conformations.

An Investigation of the Anomalous Staining of Chromatin by the Acid Dyes, Methyl Blue and Aniline Blue

1962 ◽  
Vol s3-103 (64) ◽  
pp. 519-530
Author(s):  
R. B. McKAY
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Methyl Blue ◽  
Aniline Blue ◽  
Acid Dyes ◽  
Dna And Rna ◽  
Basic Dyes ◽  
Blue Stain ◽  
High Degree ◽  
Mechanism Of The Reaction

Methyl blue and aniline blue, though acid dyes, stain the chromatin of the spermatogenetic cells of the mouse (especially of the primary spermatocytes) strongly. Extraction of the basiphil nucleic acid constituents from the chromatin causes loss of this property, while destruction of acidophilia in the protein constituents does not. It has been concluded that the dyes interact with the nucleic acids. Further, they appear to react with both DNA and RNA in the chromatin, although they show no affinity for the cytoplasm of the exocrine cells in sections of pancreas, which is rich in RNA. The mechanism of the reaction has not been fully elucidated, although apparently the dyes do not behave as basic dyes towards the nucleic acids, and the interaction is non-ionic. Methyl blue and aniline blue stain strongly other ‘acidic’ substrates, such as cellulose and nitrocellulose, and attempts have been made to relate the staining of nucleic acids to the staining of these substrates, particularly cellulose; for the staining properties of this substrate have been intensively investigated elsewhere. No satisfactory correlation, however, has been obtained, for nitrocellulose has been found to be less strongly stained at pH 3.0 than at pH 7.1, while the reverse is true for cellulose. Further, only one of 3 direct cotton dyes used appears to have any affinity for the chromatin of the spermatogenetic cells. Direct cotton dyes have large flat molecules with a high degree of conjugation. It is suggested that these characteristics are essential for interaction with nucleic acids, and also that the molecule must be reasonably compact. Finally, it has been shown that methyl blue, aniline blue, and 3 direct cotton dyes of the azo type have no ability to stain the glycogen in liver cells, yet glycogen is very closely related to cellulose.

scholarly journals A Combined ELONA-(RT)qPCR Approach for Characterizing DNA and RNA Aptamers Selected against PCBP-2

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1213 ◽  
Author(s):  
Miguel Moreno ◽  
María Fernández-Algar ◽  
Javier Fernández-Chamorro ◽  
Jorge Ramajo ◽  
Encarnación Martínez-Salas ◽  
...  
Keyword(s):  
Binding Capacity ◽  
Rna Aptamers ◽  
Dna Aptamers ◽  
General Strategy ◽  
Label Free ◽  
Mobility Shift ◽  
Real Time Quantitative Pcr ◽  
High Affinity ◽  
Dna And Rna ◽  
Electrophoretic Mobility Shift Assays

Improvements in Systematic Evolution of Ligands by EXponential enrichment (SELEX) technology and DNA sequencing methods have led to the identification of a large number of active nucleic acid molecules after any aptamer selection experiment. As a result, the search for the fittest aptamers has become a laborious and time-consuming task. Herein, we present an optimized approach for the label-free characterization of DNA and RNA aptamers in parallel. The developed method consists in an Enzyme-Linked OligoNucleotide Assay (ELONA) coupled to either real-time quantitative PCR (qPCR, for DNA aptamers) or reverse transcription qPCR (RTqPCR, for RNA aptamers), which allows the detection of aptamer-target interactions in the high femtomolar range. We have applied this methodology to the affinity analysis of DNA and RNA aptamers selected against the poly(C)-binding protein 2 (PCBP-2). In addition, we have used ELONA-(RT)qPCR to quantify the dissociation constant (Kd) and maximum binding capacity (Bmax) of 16 high affinity DNA and RNA aptamers. The Kd values of the high affinity DNA aptamers were compared to those derived from colorimetric ELONA performed in parallel. Additionally, Electrophoretic Mobility Shift Assays (EMSA) were used to confirm the binding of representative PCBP-2-specific RNA aptamers in solution. We propose this ELONA-(RT)qPCR approach as a general strategy for aptamer characterization, with a broad applicability in biotechnology and biomedicine.

Dog sperm DNA: Raw semen evaluation with Toluidine blue stain

2019 ◽  
Vol 54 (8) ◽  
pp. 1078-1084 ◽  
Author(s):  
Norma E. Monachesi ◽  
Deborah Neild ◽  
Maria Carretero
Keyword(s):  
Toluidine Blue ◽  
Sperm Dna ◽  
Blue Stain

140. THE DEVELOPMENT OF THE PHALLUS IN A MARSUPIAL

2009 ◽  
Vol 21 (9) ◽  
pp. 59
Author(s):  
K. Chew ◽  
A. Pask ◽  
G. Shaw ◽  
M. B. Renfree
Keyword(s):  
Sexual Differentiation ◽  
Alternative Model ◽  
External Genitalia ◽  
Early Embryo ◽  
Transport Protein ◽  
Embryonic Patterning ◽  
High Affinity ◽  
Cognate Receptor ◽  
Key Genes ◽  
Signalling Cascade

The phallus, the limbs and the tail are all considered appendages in the developing mammal. In mice, several key genes including FGF8, BMP4, SHH, DLX5 and DLX6 are known to control the precise pattering of the limb and phallus in the fetus (reviewed in Yamada et al. 2006). The signalling cascade in both appendages begins with SHH interacting with FGF8. In humans, disruptions to these gene pathways result in malformations of both limbs and phallus because these appendages share conserved elements in patterning and development (Yamada et al. 2003). However, this is a poorly researched area so additional models are needed to provide a greater perspective into mammalian embryonic patterning especially of the external genitalia. In marsupials, since most sexual differentiation occurs after birth, the developing phallus and limbs are accessible at stages that occur in utero in humans and other eutherian mammals. We have used the tammar as an alternative model to understand the differentiation of the phallus and limb. FGF8, SHH and megalin mRNA and protein are all expressedin the limb and phallus from the early embryo until post-natal stages. SHH and megalin were co-localised in the urethral epithelium of the tammar phallus. This is the first study to detect megalin in the developing mammalian phallus. SHH is a critical gene in patterning the appendages, and megalin is a transport protein that ferries steroids into the cell where they can bind to their cognate receptor. It has a high affinity for the potent androgen androstanediol, an androgen critical for virilisation of the tammar phallus (Leihy et al. 2004). Further examination is underway to confirm whether the expression of the genes patterning the phallus in the mouse are conserved in the marsupial and whether megalin plays any role in the patterning of the phallus, possibly mediated by SHH.

Binding of androgens in 5α-reductase-deficient human genital skin fibroblasts: inhibition by progesterone and its metabolites

1982 ◽  
Vol 94 (3) ◽  
pp. 415-427 ◽  
Author(s):  
M. B. Hodgins
Keyword(s):  
Androgen Receptor ◽  
Androgen Receptors ◽  
Cultured Cells ◽  
Reductase Activity ◽  
External Genitalia ◽  
Skin Fibroblasts ◽  
Urogenital Sinus ◽  
Receptor Complexes ◽  
High Affinity ◽  
Receptor Sites

Binding of [3H]testosterone and 5α-dihydro[3H]testosterone ([3H]DHT) to specific androgen-receptor sites of 5α-reductase-deficient human genital skin fibroblasts (five cell-lines) was studied in the intact cultured cells at 37 °C. Under the conditions of the experiments, conversion of [3H]testosterone into [3H]DHT was negligible. Both steroids bound to the same set of high-affinity saturable sites in cytoplasmic and nuclear fractions of the cells. Unlabelled testosterone, DHT and methyltrienolone competed effectively with the labelled steroids. Progesterone and oestradiol were weaker competitors; cortisol did not compete. The dissociation constant (Kd) for high-affinity complexes with [3H]testosterone (0·44 ± 0·035 nmol/l) was higher than that for [3H]DHT complexes (0·20 ± 0·090 nmol/l). Unlabelled DHT was more effective than unlabelled testosterone in competing with either radioactive steroid. Complexes of [3H]DHT and receptor dissociated more slowly than [3H]testosterone-receptor complexes and [3H]DHT bound more extensively to low-affinity non-saturable sites in fibroblasts. As judged by competition with the radioactive androgens, progesterone bound to the androgen receptor with a Kd of about 7 nmol/l. 5α-Pregnane-3,20-dione had an approximately fivefold lower affinity than progesterone for androgen receptors; 3α/β- or 20α-reduction lowered its affinity further. It is suggested that in 5α-reductase deficiency in man, progesterone in amniotic fluid and blood could effectively inhibit testosterone binding to androgen receptors in the male embryonic external genitalia. One function of the high levels of 5α-reductase activity normally found in embryonic external genitalia and urogenital sinus may be to protect these tissues from the potentially antiandrogenic action of progesterone.

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