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Concept: Silver stain


Woodpeckers experience forces up to 1200-1400 g while pecking. It is assumed due to evolutionary adaptations, the woodpecker is immune to brain injury. This assumption has led to the use of the woodpecker as a model in the development of sports safety equipment such as football helmets. However, it is unknown at this time if the woodpecker brain develops neuro-trauma in relation to the high g-forces experienced during pecking. The brains of 10 ethanol preserved woodpeckers and 5 ethanol preserved red-winged black bird experimental controls were examined using Gallyas silver stain and anti-phospho-tau. The results demonstrated perivascular and white matter tract silver-positive deposits in eight out of the 10 woodpecker brains. The tau positive accumulations were seen in white matter tracts in 2 of the 3 woodpeckers examined. No staining was identified in control birds. The negative staining of controls birds contrasted with the diffuse positive staining woodpecker sections suggest the possibility that pecking may induce the accumulation of tau in the woodpecker brain. Further research is needed to better understand the relationship.

Concepts: Traumatic brain injury, Bird, White matter, Staining, Silver stain, Negative stain, Woodpecker, Phosphotungstic acid


We show that the insect ovipositor is an olfactory organ that responds to volatiles and CO2 in gaseous form. We demonstrate this phenomenon in parasitic wasps associated with Ficus racemosa where ovipositors, as slender as a human hair, drill through the syconium (enclosed inflorescences) and act as a guiding probe to locate highly specific egg-laying sites hidden inside. We hypothesize that olfaction will occur in the ovipositors of insects such as parasitic fig wasps where the hosts are concealed and volatile concentrations can build up locally. Relevant stimuli such as herbivore-induced fig volatiles and CO2 elicited electrophysiological responses from the ovipositors. Silver nitrate staining also revealed pores in ovipositor sensilla, indicating their olfactory nature. Insects could use volatile sensors on their ovipositors to evaluate ecologically relevant stimuli for oviposition. Further investigations on the sensory nature of ovipositors can provide designs for development of ovipositor-inspired micro-chemosensors.

Concepts: Insect, Sense, Primate, Ficus, Wasp, Ant, Hymenoptera, Silver stain


Silver staining, exploiting the special bioaffinity and the chromogenic reduction of silver ions, is an indispensable visualization method in biology. It is a most popular method for in-gel protein detection. However, it has been challenged with run-to-run viability, background staining, inability for protein quantification and limited compatibility with mass spectroscopic (MS) analysis, which are largely attributed to the tricky chromogenic visualization. Here, we reported a novel water-soluble fluorogenic Ag+ probe, whose sensing is based on an aggregation-induced emission (AIE) process driven by tetrazolate-Ag+ interactions. The fluorogenic sensing can substitute the chromogenic reaction, leading to a new silver fluorescence staining method. This new staining method offers sensitive detection of total proteins in polyacrylamide gel with broad linear dynamic range and robust operations that rival silver nitrate stain and the best fluorescent stain.

Concepts: Protein, Oxygen, Molecular biology, Biology, Silver, Staining, Silver nitrate, Silver stain


A 56-year-old woman presented with periocular nodules that were clinically suspected to be neurofibromas. Histopathologic examination of excised nodules revealed a pronounced granulomatous reaction to a foreign material that was composed of glossy polygonal palely eosinophilic fragments. These fragments were outlined in red with Masson trichrome, stained gray with the elastic stain, and were uniformly red with Gomori methenamine silver staining. The histopathologic appearance was consistent with a granulomatous reaction to Dermalive facial filler. Postoperatively the patient admitted that she had filler injections many years earlier in another country, and that nodules appeared 1 year after injection. Treatment with steroids, intralesional immunosuppressive agents and surgery had been previously attempted to eradicate the nodules. The literature pertaining to granulomatous reactions to Dermalive and related hybrid facial fillers is reviewed and treatment options are discussed. This report is the first to illustrate the unique histopathologic staining characteristics of Dermalive, which may be useful to ophthalmic pathologists in identifying this uncommon foreign material.

Concepts: Anatomical pathology, Tuberculosis, Crohn's disease, Staining, Stain, Sarcoidosis, Granuloma, Silver stain


3-(2-furoyl)quinoline-2-carboxaldehyde (FQ) is a sensitive fluorogenic dye, used for derivatization of proteins for SDS-capillary gel electrophoresis with laser induced fluorescence detection (SDS-CGE-LIF) at silver staining sensitivity (ng/ml). FQ labels proteins at primary amines, found at lysines and N-termini, which vary in number and accessibility for different proteins. This work investigates the accuracy of estimation of protein concentration with SDS-CGE-LIF in real biological samples, where a different protein must be used as a standard. 16 purified proteins varying in molecular weight, structure and sequence were labelled with FQ at constant mass concentration applying a commonly used procedure for SDS-CGE-LIF. The fluorescence of these proteins was measured using a spectrofluorometer and found to vary with a relative standard deviation of 36%. This compares favourably with other less sensitive methods for estimation of protein concentration such as SDS-CGE-UV and SDS-PAGE-Coomassie and is vastly superior to the equivalently sensitive silver stain. Investigation into the number of labels bound with UHPLC-ESI-QTOF-MS revealed large variations in the labelling efficiency (percentage of labels to the number of labelling sites given by the sequence) for different proteins (from 3-30%). This explains the observation that fluorescence per mole of protein was not proportional to the number of lysines in the sequence. This article is protected by copyright. All rights reserved.

Concepts: Protein, Fluorescence, Amino acid, Molecular biology, Gel electrophoresis, Staining, Copyright, Silver stain


Sperm morphometry has some value as an indicator of reproductive capacity in males. In laboratory practice a variety of slide-staining methods are used during morphological evaluation of semen to predict male fertility. The aim of this study was to determine the effect of staining of semen using four different techniques on the morphometry of the bull sperm cell. The material for the study consisted of semen collected from test bulls of the Black-and-White variety of Holstein-Friesians. The results obtained in the study indicate differences in the dimensions of bull sperm heads when different slide staining techniques were used. The most similar results for sperm head dimensions were obtained in the case of SpermBlue(®) and eosin+gentian violet complex, although statistically significant differences were found between all the staining techniques. Extreme values were noted for the other staining techniques - lowest for the Papanicolaou and highest for silver nitrate, which may indicate more interference in the cell by the reagents used in the staining process. However, silver nitrate staining was best at identifying the structures of the sperm cell. Hence it is difficult to determine which of the staining methods most faithfully reveals the dimensions and shape of the bull sperm.

Concepts: Reproduction, Sperm, Statistical significance, Fertility, Spermatozoon, Semen, Gamete, Silver stain


Abstract Background: We report a case of allergic fungal sinusitis (AFS) involving the lacrimal sac and review the current English literature. A literature search for AFS involving the lacrimal sac revealed two reports with only one of the two cases demonstrating histological evidence of fungal elements. This is just the third such case and only the second reported case with histopathologic confirmation of fungal elements by Gomori methenamine silver (GMS) stain. Materials and Methods: A PubMed database search was performed using combinations of the following key words: allergic fungal sinusitis, lacrimal sac, nasolacrimal duct, ophthalmology, epiphora, orbit. A 70-year-old white man with a history of chronic conjunctivitis and nasal polyps presenting with chronic epiphora was found to have dacryostenosis on the left side. A CT scan of the orbits revealed mucoperiosteal thickening completely obliterating the frontal, ethmoid and sphenoid sinuses. Results: A left external dacryocystorhinostomy (DCR) was performed and the lacrimal sac contents were studied histopathologically. Microscopic examination of the lacrimal sac contents disclosed allergic mucin with laminated aggregates of eosinophils in various stages of degeneration, Charcot-Leyden crystals and rare noninvasive fungal hyphae confirming the diagnosis of AFS. Fungal elements stained positively with Gomori methenamine silver stain. Conclusion: Although rarely reported, AFS can affect the lacrimal sac. AFS should be suspected in patients with a history of recurrent refractory sinusitis, recurrent dacryocystitis and nasal polyposis. Early diagnosis is important for adequate treatment and prevention of recurrence.

Concepts: Pathology, Sinusitis, Microscope, Nasal polyp, Lacrimal sac, Lacrimal apparatus, Nasolacrimal duct, Silver stain


BACKGROUND: Histoplasmosis has a textbook cytologic description with numerous intracellular organisms that are readily apparent on routine stains. This is based on series and reports describing histoplasmosis in immunosuppressed patients with disseminated disease. With the advent of ultrasound-guided (US) fine-needle aspiration (FNA) techniques, a marked increase in the cytologic diagnosis of histoplasmosis in immunocompetent patients is noted. METHODS: A search identified all cytology cases diagnosed with Histoplasma within the past 10 years. Cases were reviewed, along with patient demographic, clinical, and laboratory data. RESULTS: A total of 40 FNA cases of histoplasmosis were identified. Patients ranged in age from 15 years to 86 years. There were 23 female patients and 17 male patients; 37 were immunocompetent and 3 were immunosuppressed. Sixteen patients were being staged for primary tumors of other sites; others presented with primary pulmonary symptoms or histoplasmosis was noted incidentally. Specimens were composed of bland acellular necrosis, most commonly with granulomas (77.5%); only rare intracellular organisms were present on routine stains, and variable extracellular organisms were noted on Grocott methenamine silver stain (GMS) stain. GMS stain on direct smears was found to be more sensitive than cell block. Laboratory studies for urine antigen, yeast, and mycelial antibody (by compliment fixation), serum antibody (by immunodiffusion), and culture were positive in 11.8%, 59.1%, 4.5%, 47.6%, and 3.4% of cases, respectively. CONCLUSIONS: In an endemic region, histoplasmosis presents more commonly in immunocompetent patients as localized fibrocaseous disease on FNA and is often identified by high-resolution imaging. FNA is increasingly used in the diagnosis because of endoscopic ultrasound and endobronchial ultrasound. GMS stain on direct smears is more sensitive than cell block. In general, laboratory tests have low sensitivity in this patient population. Cancer (Cancer Cytopathol) 2013. © 2013 American Cancer Society.

Concepts: Immune system, Cancer, Biology, Biopsy, Pathology, American Cancer Society, Medical laboratory, Silver stain


A 7-year-old Siamese cat presenting with three ulcerated cutaneous nodules in the lumbar-sacral region was seen at the Laboratory for Clinical Research on Dermatozoonoses in Domestic Animals in Rio de Janeiro, Brazil. Histopathological analysis showed that the lesions consisted of polyhedral and spindle-shaped voluminous mononuclear cells with loose chromatin and clearly visible nucleoli, few giant cells, and foci of coagulative and caseous necrosis - findings suggestive of a vaccine induced sarcoma. No significant mitotic rate, cytological atypias or asteroid bodies were observed. Special histopathological staining with periodic acid-Schiff and Grocott’s silver stain demonstrated the presence of small yeast cells characterized by simple and narrow-base budding compatible with Sporothrix schenckii. Mycological culture grew S schenckii. Cytopathology was negative for yeast cells. These atypical clinical and histopathological signs support the importance of histopathological analysis with special staining techniques, in addition to mycological culture in the diagnosis of feline sporotrichosis.

Concepts: Cell nucleus, Biology, Cell biology, Yeast, Anatomical pathology, Staining, Rio de Janeiro, Silver stain