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Archive: October 2020

Exocytosis in a Skeletal Muscle Biopsy

Exocytosis, Neuro Notes, arkana laboratories, muscle biopsy
This electron micrograph of two adjacent skeletal muscle cells demonstrates simultaneous exocytosis.  Exocytosis in this case shows extravasation of lysosomes from inside the muscle fiber's cytoplasm by fusion with the plasma membrane (aka sarcolemma) and being expelled into the extracellular space beneath the basement membrane (aka basal lamina).  Exocytosis is one mechanism for remodeling of the sarcolemmal membrane that takes place under physiological and pathophysiological conditions, including trafficking of transmembrane machinery, muscle fiber regeneration following injury, and denervation.  Much has been written on this topic, but the details at the molecular level are still being elucidated.  (Electron micrograph original magnification:...

Twitter Poll (October 28, 2020)

Medullary angiitis, renal pathology, kidney disease, arkana laboratories
Answer: C Medullary angiitis is a histopathologic lesion within the renal medulla that is characterized by interstitial hemorrhage with associated neutrophilic inflammation and karorrhectic debris. While the finding is somewhat non-specific in etiology, it has been seen in cases of ANCA-associated glomerulonephritis, IgA nephropathy, and patients with prior infection treated with antibiotics (see reference). Reference: Hendricks AR, Harris AA, Walker PD, et al. Renal medullary angiitis: a case series from a single institution. Human Pathology (2013); (44): 521-525.  

Arkana Holiday Tales: Dr. May

Introducing Arkana Holiday Tales!   As we approach the upcoming holiday season, our physicians would like to share stories, memories, and traditions surrounding their favorite holidays. Each Saturday we will post a new tale!   Up first is Dr. May!      

Sarcoidosis in a Skeletal Muscle Biopsy

sarcoidosis, neuro notes, arkana laboratories
These images show skeletal muscle from the thigh of an African-American patient with muscle weakness and elevated CPK levels.  Occasional well-formed non-caseating granulomota with mild surrounding chronic lymphoid inflammation are present. These morphologic findings are consistent with the presence of granulomatous myositis, and compatible with sarcoidosis: clinical correlation is required. (hematoxylin and eosin stained frozen section 100x and 200x magnification).    

Dr. Dvanajscak Takes the MYMP

resistant starch, Dvanajscak, MYMP, CKD, Arkana Laboratories
Dr. Dvanajsack was a part of a team of physicians who published a paper discussing how resistant starch (RS) improves CKD outcomes. In this report, the physicians study how RS modulates host‐microbiome interactions in CKD by measuring changes in the abundance of proteins and bacteria in the gut. Read the Paper: Resistant Starch Slows the Progression of CKD in the 5/6 Nephrectomy Mouse Model Who will take the MYMP next?

Diagnose This (October 19, 2020)

Sarcoidosis, kidney biopsy stain, arkana laboratories, renal pathology
What would be your leading diagnosis in a patient with elevated ACE levels and hilar lymphadenopathy?      ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​ ​   ​ ​   ​ ​...

A MYMP For Membranous Lupus Nephritis

Membranous Lupus Nephritis, arkana laboratories, nephropathology
Dr. Caza and Dr. Kuperman (along with Dr. Sharma, Dr. Dvanajscak, and Dr. Larsen), recently published a paper covering membranous lupus nephritis. Read the paper: Neural Cell Adhesion Molecule 1 Is A Novel Autoantigen in Membranous Lupus Nephritis Tune in next week to see who will catch the MYMP!

Lipid Storage Myopathy

Lipid Storage Myopathy, Arkana Laboratories, neuro notes, neuropathology, molecular pathology
This adult patient presented with progressive muscle weakness, elevated CK, and was admitted for rhabdomyolysis. Skeletal muscle biopsy was performed of the quadriceps (Image 1, Hematoxylin and eosin-stained frozen section, original magnification x200). What is your diagnosis?   Answer:  Lipid Storage Myopathy Optically clear spaces within muscle may be due to lipid or glycogen.  Optically clear spaces may also occur due to ice crystal formation when muscle biopsy tissue is frozen too slowly or is edematous (so-called "freezing artifact").  In this case, the vacuoles are due to abnormal accumulation of lipid (i.e. Lipid Storage Myopathy), see Image 2.  (Figure 2:  Oil-red-O...