Stain technology最新文献

In situ hybridization with DNA probes labeled with biotin and detected by the avidin-alkaline phosphatase/5-bromo-chloroindoxyl phosphate-nitro blue tetrazolium system has been used to localize DNA sequences in chromosomes. To observe the hybridization signals, a phase contrast microscope has often been used because of the good visibility it provides. Use of a 595 nm band pass filter with the phase contrast microscope enhances signal contrast after in situ hybridization without reducing resolution.

Immunocytochemical staining has been widely used for localizing various hormonal antigens, protein markers and putative neurotransmitters in tissues. Immunostained sections can be examined light microscopically and specific areas selected for electron microscopic study.

An improved method for preparing and staining ground tissue-implant sections for light microscopy is presented. Undecalcified tissue blocks with titanium implants were dehydrated in an ascending series of ethanol and stained in toto with basic fuchsin. Specimens were infiltrated and embedded in methyl methacrylate and sections were prepared using a cutting-grinding-system. The polished surface was counterstained with light green or anilin blue. Light polymerizing resin was used as slide mounting medium and for mounting the coverglass. The sections obtained were 10-15 microns thick with tissue architecture which clearly differentiated structures at the tissue-implant interface. The method was very useful for computer assisted morphometric analysis.

The use of formalin or Michel's solution either alone or in combination with acetone, and acetone, methanol or ethanol alone as fixatives, and glycol methacrylate as embedding medium were evaluated for their suitability in procedures to detect lymphocyte membrane antigens by OKT and Leu monoclonal antibodies in human tonsils. No staining was detected in sections fixed in 70% or absolute ethanol and embedded in glycol methacrylate with either the direct immunofluorescence or avidin-biotin methods. Fixation in Michel's solutions plus acetone at room temperature revealed staining by both. Neither method resulted in staining after fixation in Michel's solution plus acetone at 4 C presumably due to the slow action of the fixative. Staining was enhanced using a combination of primary and secondary biotinylated antibodies. Dual staining allowed concurrent detection of two antigens in the same section. Glycol methacrylate embedding is a possible replacement for ultracold storage in the preservation of tissue for immunofluorescent staining.

A versatile mineralized bone stain (MIBS) for demonstrating osteoid seams and tetracycline fluorescence simultaneously in thin or thick undecalcified sections has been developed. Bone specimens are fixed in 70% ethanol, but 10% buffered formalin is permissible. Depending upon one's preference, these specimens can be left unstained or be prestained before plastic embedding. Osteoid seams are stained green to jade green, or light to dark purple. Mineralized bone matrix is unstained or green. Osteoblast and osteoclast nuclei are light to dark purple, cytoplasm varies from slightly gray to pink. The identification of osteoid seams by this method agrees closely with identification by in vivo tetracycline uptake using the same section from the same biopsy. The method demonstrates halo volumes, an abnormal, lacunar, low density bone around viable osteocytes in purple. This phenomenon is commonly seen in vitamin D-resistant rickets, fluorosis, renal osteodystrophy, hyperparathyroidism, and is sometimes seen in fluoride treated osteoporotic patients. In osteomalacic bone, most osteoid seams are irregularly stained as indicated by the presence of unmineralized osteoid between mineralized lamellae. The method has been used effectively in staining new bone formation in hydroxyapatite implants and bone grafts. Old, unstained, plastic embedded undecalcified sections are stained as well as fresh sections after removal of the coverslip. This stain also promises to be valuable in the study of different metabolic bone diseases from the point of view of remodeling, histomorphometry, and pathology.

Bovine nasal cartilage proteoglycan monomers were studied by Kleinschmidt and Zahn's molecular spreading technique as modified by Rosenberg et al. By decreasing the cytochrome c concentration in the epiphase to 2 micrograms per 100 microliters we were able on nitrocellulose-coated grids routinely to obtain highly contrasted and well spread proteoglycan monomers with a characteristic brush-like appearance and, sometimes, a clearly distinguishable hyaluronic acid binding region. Previously, a hyaluronic acid binding region has only been observed routinely in spread proteoglycan aggregates, and a brush-like structure of proteoglycan monomers on carbon-coated grids, but with considerably less precision due to the poor contrast of the molecules. Molecular spreading was further improved by decreasing the cytochrome c concentration in the epiphase to less than 2 micrograms per 100 microliters, but contrast was reduced making visualization of molecular details difficult.