scholarly journals Clinical and Ultrastructural Studies of Gelatinous Drop-Like Corneal Dystrophy (GDLD) of a Patient with TACSTD2 Gene Mutation

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Ali Masmali ◽  
Aljoharah Alkanaan ◽  
Hind M. Alkatan ◽  
Omar Kirat ◽  
Abdullah Ayidh Almutairi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amyloid Fibrils ◽  
Polarized Light ◽  
Corneal Dystrophy ◽  
Corneal Tissue ◽  
Ultrastructural Studies ◽  
Amyloid Deposits ◽  
Exon 1 ◽  
Pas Staining ◽  
The Right

Purpose. To describe clinical, molecular genetics, histopathologic and ultrastructural findings of gelatinous drop-like corneal dystrophy (GDLD) (OMIM #204870) in a Sudanese patient. Method. An ocular examination revealed the onset of GDLD in a Sudanese patient (50 years old) at King Khalid Specialist Hospital, Riyadh. The 333 sequence variants in 13 GDLD genes of a DNA sample were screened by Asper Ophthalmics Ltd. It was further confirmed by sequencing. The patient had undergone a penetrating keratoplasty in the right eye. The corneal tissue was processed for histopathology and ultrastructural studies. Results. Slit-lamp observation showed grayish-white multiple superficial corneal nodules of various sizes in the left and right eye. Both corneas became clear after the surgery. The GDLD deposits in the subepithelial region and in the anterior stroma were confirmed by PAS staining and their apple-green birefringence under polarized light. Ultrastructurally, the amyloid fibrils were very thin and grouped in whorl-like structures, which caused splits between and within the stromal lamellae. Collagen fibrils (CFs) and keratocytes had degenerated. A homozygous c.355T > A mutation in exon 1 of the TACSTD2 (M1S1) gene was detected, and alteration of the amino acid (p.Cysl19Ser in NCBI entry NP_002344.2) was observed. Conclusion. In our patient with GDLD, a “c.355T > A” mutation in exon 1 of TACSTD2 was detected and believed to be responsible for the alteration of the amino acid leading to the formation of the amyloid deposits. The deposits caused the ultrastructural degeneration of epithelium, Bowman’s layer, stroma, and keratocytes of the GDLD cornea.

Amyloidosis

2020 ◽  
pp. 2218-2234
Author(s):  
Mark B. Pepys ◽  
Philip N. Hawkins
Keyword(s):  
Amyloid Fibrils ◽  
Amyloid Fibril ◽  
Polarized Light ◽  
Serum Amyloid ◽  
Amyloid P Component ◽  
Serum Amyloid P ◽  
Serum Amyloid P Component ◽  
Amyloid Deposits ◽  
Amyloid P

Amyloidosis is the clinical condition caused by extracellular deposition of amyloid in the tissues. Amyloid deposits are composed of amyloid fibrils, abnormal insoluble protein fibres formed by misfolding of their normally soluble precursors. About 30 different proteins can form clinically or pathologically significant amyloid fibrils in vivo as a result of either acquired or hereditary abnormalities. Small, focal, clinically silent amyloid deposits in the brain, heart, seminal vesicles, and joints are a universal accompaniment of ageing. Clinically important amyloid deposits usually accumulate progressively, disrupting the structure and function of affected tissues and lead inexorably to organ failure and death. There is no licensed treatment which can specifically clear amyloid deposits, but intervention which reduces the availability of the amyloid fibril precursor proteins can arrest amyloid accumulation and may lead to amyloid regression with clinical benefit. Pathology—amyloid fibrils bind Congo red dye producing pathognomonic green birefringence when viewed in high-intensity cross-polarized light, and the protein type can be identified by immunostaining or proteomic analysis. Amyloid deposits always contain a nonfibrillar plasma glycoprotein, serum amyloid P component, the universal presence of which is the basis for use of radioisotope-labelled serum amyloid P component as a diagnostic tracer. Clinicopathological correlation—amyloid may be deposited in any tissue of the body, including blood vessels walls and connective tissue matrix; clinical manifestations are correspondingly diverse. Identification of the amyloid fibril protein is always essential for appropriate clinical management. The specific types of amyloidosis covered in this chapter are reactive systemic (AA) amyloidosis, monoclonal immunoglobulin light chain (AL) amyloidosis, and hereditary systemic amyloidoses (including familial amyloid polyneuropathy).

scholarly journals ISOLATION AND IDENTIFICATION BY SEQUENCE ANALYSIS OF EXPERIMENTALLY INDUCED GUINEA PIG AMYLOID FIBRILS

1974 ◽  
Vol 140 (3) ◽  
pp. 871-876 ◽  
Author(s):  
Martha Skinner ◽  
Edgar S. Cathcart ◽  
Alan S. Cohen ◽  
Merrill D. Benson
Keyword(s):  
Amino Acid ◽  
Sequence Analysis ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Amyloid Fibrils ◽  
Protein A ◽  
Terminal Sequence ◽  
Isolation And Identification ◽  
Amyloid Deposits ◽  
Immunologic Analysis

Amyloidosis was produced experimentally in guinea pigs by multiple casein injections. Amyloid fibrils were isolated and fractionated and a protein obtained that had an amino acid composition comparable with A protein, a unique nonimmunoglobulin constituent of secondary amyloid deposits. N-terminal sequence analysis demonstrated a sequence homologous with that of A proteins from human and monkey preparations but preceded by a 5-residue peptide which had an N-terminal histidine. A definite species specificity in A protein from human and guinea pig was identified on immunologic analysis.

scholarly journals Fluorescence detection of amyloid deposits in human tissues using histochemical dyes

2021 ◽  
Author(s):  
VV Guselnikova ◽  
DA Sufieva ◽  
DL Tsyba ◽  
DE Korzhevskii
Keyword(s):  
Fluorescence Microscopy ◽  
Fluorescence Detection ◽  
Congo Red ◽  
Amyloid Fibrils ◽  
Polarized Light ◽  
Methyl Violet ◽  
Human Tissues ◽  
Transthyretin Amyloidosis ◽  
Amyloid Deposits ◽  
Β Amyloid

Recently, fluorescence microscopy becomes more available, presenting new opportunities to face several challenges of experimental biology and medicine. The study was aimed to assess the effectiveness of fluorescence microscopy for the identification of amyloid deposits in human tissues. Post-mortem samples of the myocardium (n = 12) and cerebral cortex (n = 8) obtained from subjects of both sexes aged 60–98 with verified amyloidosis were used as a material for the study. The specimens were stained using 11 different histochemical dyes and subsequently analyzed by light and fluorescence microscopy. Qualitative and quantitative analysis has shown that Thioflavin T is the most effective stain for fluorescence detection of β- and transthyretin amyloid in human tissues. Congo red staining is highly effective for the detection of transthyretin amyloidosis, however, it is ill-suited for the identification of β-amyloid plaques. It has been found that the ability of Congo red to exhibit fluorescence when binding to amyloid fibrils can be used for verification of amyloid deposits instead of the traditional polarized light microscopy. As has been first noted, methyl violet can selectively bind to β-amyloid with fluorescent complex formation. In addition, methyl violet treatment effectively reduces the autofluorescent background in the nervous tissue. This makes methyl violet staining a promising diagnostic tool for Alzheimer's-type pathology.

Structural Biology

2014 ◽  
Author(s):  
Ronald Wetzel ◽  
Rakesh Mishra
Keyword(s):  
Amino Acid ◽  
Protein Interactions ◽  
Amyloid Fibrils ◽  
Intrinsically Disordered Protein ◽  
Structural Motif ◽  
Protein Protein Interactions ◽  
Post Translational Modifications ◽  
Intrinsically Disordered ◽  
Exon 1 ◽  
Molecular Therapeutic

The 3,144–amino acid huntingtin protein (HTT) folds in water into a structure consisting of compact, organized domains interspersed with intrinsically disordered protein (IDP) elements. The IDPs function as sites of post-translational modifications and proteolysis as well as in targeting, binding, and aggregation. Although the dominant structural motif of HTT is the α‎-helix–rich HEAT repeat, the expanded polyglutamine (polyQ) toxicity responsible for Huntington’s disease is most likely played out within intrinsically disordered HTT exon 1–like fragments consisting of the 16– to 17–amino acid N-terminal HTTNT segment, the polyQ segment, and a proline-rich segment. The physical behavior of HTT exon 1 fragments is dominated by interactive, polyQ repeat length–dependent structural transitions responsible for membrane and protein–protein interactions and the formation of tetramers, higher oligomers, amyloid fibrils, and inclusions. Understanding the basis of this solution behavior may be the key to disease mechanisms and molecular therapeutic strategies.

scholarly journals First Case of Nodular Localized Primary Cutaneous Amyloidosis Treated With Bortezomib and Dexamethasone

2021 ◽  
Vol 9 ◽  
pp. 232470962110584
Author(s):  
Noman Ahmed Jang Khan ◽  
Emma Nellhaus ◽  
Doreen Griswold ◽  
Muhammad Omer Jamil
Keyword(s):  
Mass Spectrometry ◽  
Laser Therapy ◽  
Congo Red ◽  
Amyloid Fibrils ◽  
Laser Microdissection ◽  
Polarized Light ◽  
Surgical Excision ◽  
Rare Form ◽  
First Case ◽  
Amyloid Deposits

Nodular localized cutaneous amyloidosis is a rare form of cutaneous amyloidosis and is characterized by an extracellular deposition of insoluble amyloid fibrils which are either primarily cutaneous or a manifestation of an underlying systemic amyloidosis. Biopsy of the lesion is mandatory for the diagnosis, and histopathology shows diffuse amyloid deposits with plasmacytic infiltration. Apple-green birefringence characteristic of amyloidosis is observed when stained with Congo red and viewed under polarized light. Amyloid subtyping is done with laser microdissection followed by mass spectrometry. Majority of these lesions do not require any treatment but surgical excision, shave excision, laser therapy, and radiotherapy can be considered for symptomatic nodular localized primary cutaneous amyloidosis (NLPCA). We present a case of recurrent NLPCA in a 64-year-old woman who was treated with bortezomib and dexamethasone after failing several local therapies with excellent response.

Adrenocorticotropin Production by a Mammary Carcinoma

1977 ◽  
Vol 35 ◽  
pp. 462-463
Author(s):  
K.S. McCarty ◽  
N.R. Wallace ◽  
W. Litaker ◽  
S. Wells ◽  
G. Eisenbarth
Keyword(s):  
Adrenocorticotropic Hormone ◽  
Small Cell ◽  
Hormone Production ◽  
Carcinoma Of The Breast ◽  
Ectopic Acth ◽  
Ultrastructural Studies ◽  
Subcutaneous Metastases ◽  
Ectopic Acth Production ◽  
The Right ◽  
Pituitary Carcinomas

The production of adrenocorticotropic hormone by non-pituitary carcinomas has been documented in several tumors, most frequently small cell carcinoma of the lung, islet cell carcinomas of the pancreas, thymomas and carcinoids. Electron microscopy of these tumors reveals typical membrane-limited "neurosecretory" granules. Confirmation of the granules as adrenocorticotropin (ACTH) requires the use of OsO4 as a primary fixative to give the characteristic cored granule appearance in conjunction with immunohistochemical demonstration of the hormone peptide. Because of the rarity of ectopic ACTH production by mammary carcinomas and the absence of appropriate ultrastructural studies in the two examples of such ectopic hormone production in the literature of which we are aware (1,2), we present biochemical and ultrastructural data from a carcinoma of the breast with apparent ACTH production.The patient had her primary tumor in the right breast in 1969. The tumor recurred as visceral and subcutaneous metastases in 1976 and again in 1977.

scholarly journals Characterization of design grammar of peptides for regulating liquid droplets and aggregates of FUS

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kiyoto Kamagata ◽  
Rika Chiba ◽  
Ichiro Kawahata ◽  
Nanako Iwaki ◽  
Saori Kanbayashi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Electrostatic Interactions ◽  
Amyloid Fibrils ◽  
Droplet Formation ◽  
Liquid Droplets ◽  
Proof Of Concept ◽  
Aggregate Formation ◽  
Fused In Sarcoma ◽  
Dynamics Simulations

AbstractLiquid droplets of aggregation-prone proteins, which become hydrogels or form amyloid fibrils, are a potential target for drug discovery. In this study, we proposed an experiment-guided protocol for characterizing the design grammar of peptides that can regulate droplet formation and aggregation. The protocol essentially involves investigation of 19 amino acid additives and polymerization of the identified amino acids. As a proof of concept, we applied this protocol to fused in sarcoma (FUS). First, we evaluated 19 amino acid additives for an FUS solution and identified Arg and Tyr as suppressors of droplet formation. Molecular dynamics simulations suggested that the Arg additive interacts with specific residues of FUS, thereby inhibiting the cation–π and electrostatic interactions between the FUS molecules. Second, we observed that Arg polymers promote FUS droplet formation, unlike Arg monomers, by bridging the FUS molecules. Third, we found that the Arg additive suppressed solid aggregate formation of FUS, while Arg polymer enhanced it. Finally, we observed that amyloid-forming peptides induced the conversion of FUS droplets to solid aggregates of FUS. The developed protocol could be used for the primary design of peptides controlling liquid droplets and aggregates of proteins.

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