Neutrophil Activity and Extracellular Matrix Degradation: Drivers of Lung Tissue Destruction in Fatal COVID-19 Cases and Implications for Long COVID.

Pulmonary fibrosis, severe alveolitis, and the inability to restore alveolar epithelial architecture are primary causes of respiratory failure in fatal COVID-19 cases. However, the factors contributing to abnormal fibrosis in critically ill COVID-19 patients remain unclear. This study analyzed the histopathology of lung specimens from eight COVID-19 and six non-COVID-19 postmortems.

A comparison of staining methods for Helicobacter pylori in laparoscopic vertical sleeve gastrectomy resections.

Background: Helicobacter pylori is an important public health concern due to its status as a carcinogenic bacterium. Well adapted to the acidic environment of the human stomach, the variety of strains and virulence factors of the organism when interacting with the host immune system creates an individualistic response. Although estimates suggest that approximately half of the global population is infected with H pylori, the majority of infected persons remain asymptomatic while harboring an increased risk of intestinal metaplasia and gastric cancers.

The presence of in laparoscopic sleeve gastrectomy specimens is associated with increased mucosal thickness, presence of secondary follicles, increased chronic inflammation, and intestinal metaplasia.

Helicobacter pylori is putatively present in over half of the global human population and is recognized as a carcinogenic agent that increases the likelihood of infected patients developing gastric adenocarcinoma or gastric lymphoma. Although there are several means for testing for , the gold standard remains the invasive histologic evaluation. The current most popular form of bariatric surgery is the laparoscopic sleeve gastrectomy (LSG) and is the only bariatric surgery which supplies a specimen for histologic evaluation.

Histologic examination of canned cat food.

Cat food production is a billion-dollar industry in the United States, with most pet owners trusting pet food companies to provide their pets with complete nutrition. Moist or canned cat food is healthier than dry kibble for cats due to its higher water content promoting healthy kidney function, but ingredient labels on canned cat food are lengthy with ambiguous terminology including 'animal by-products.' Forty canned cat food samples were collected from grocery stores and were processed using routine histologic methods.

Glyoxal fixation: an immunohistochemistry assay evaluation.

Analysis of surgical pathology specimens by histological techniques including immunohistochemistry (IHC) assays is a mainstay of disease diagnosis in humans. Neutral buffered formalin (NBF) is currently the primary fixative used, but its use is not without risks due to toxicity and carcinogenicity. Several glyoxal-based fixatives have been commercially produced, are considered safer alternatives to NBF, and produce histochemical staining results comparable to that of tissues fixed in NBF.

Hidradenitis suppurativa lesions are associated with decreased collagen, decreased elastin, and increased neovascularization.

Hidradenitis suppurativa (HS) is a dermatological condition characterized by ruptured hair follicles inducing a localized, but massive chronic inflammatory response. Analysis of 104 HS lesions in formalin-fixed paraffin-embedded tissues identified the most common histologic features found associated with HS were migrating epithelial sheets, acute and chronic inflammation, perivascular chronic inflammation in regions adjacent to active lesions, and granulation tissue. Additionally, using a modified Masson's trichrome stain principally for collagen, Verhoeff van Gieson elastic stain, and CD34 immunohistochemistry assay for endothelium, lesional areas in the dermis with chronic inflammation exhibited a significant decrease in collagen and elastin, and an increase in neovascularization.

Dynamic Leukocyte Populations Are Associated With Early- and Late-stage Lesions in Hidradenitis Suppurativa.

Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition typically targeting the axillary and anogenital regions of the body. The massive inflammatory cell infiltrate produced in this cryptogenic condition has led investigators in the attempt to link particular inflammatory cell fractions and cytokines to disease development, and ultimately to disease treatment. This study qualitatively and quantitatively analyzes the white blood cell fractions of macrophages, B-lymphocytes, T-lymphocytes, plasma cells, and granulocytes in 104 HS lesions on formalin-fixed paraffin-embedded tissues using immunohistochemistry (IHC).

Glyoxal: a proposed substitute for formalin in H&E and special stains.

Neutral-buffered formalin (NBF) has been used as the primary fixative in anatomic pathology laboratories for decades. Although it yields excellent morphologic and staining results, NBF poses significant health hazards requiring tissue to be grossed under a grossing/chemical fume hood. Glyoxal fixatives offer far less toxic alternatives and do not necessitate use of a grossing hood.