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Microwave fixation and localization of calcium in synaptic vesicles.

The distribution of Ca2+ ions is demonstrated in the synaptic terminals by means of a 2-step chemical precipitation of Ca2+ ions in nervous tissue. K-oxalate/K-antimonate chemical replacement with simultaneous computerized microwave irradiation is used. This precipitate in cell structures was investigated by computerized electron probe X-ray micro-analysis. The calculated values (from the theoretical, standards and sections), elemental binding ratios and elemental molecular weight ratios were compared. Each calculated value coincided with the theoretical value. This method can reliably detect Ca2+ ions at the micromolar level. Ca2+ ions were distributed in the synaptic vesicles and surrounding membranes. Further progress is expected in freeze-substitution and in the application and propagation of the EELS-Imaging system in calcium determinations.

Animals↗

Spray-freezing freeze substitution (SFFS) of cell suspensions for improved preservation of ultrastructure.

Some unicellular organisms present challenges to chemical fixations that lead to common, yet obvious, artifacts. These can be avoided in entirety by adapting spray-freezing technology to ultrarapidly freeze specimens for freeze substitution. To freeze specimens, concentrated suspensions of cells ranging in diameter from 0.5-30 pm were sprayed with an airbrush at 140-200 kPa (1.05-1.5 torr; 20.3-29.0 psi) into a nylon mesh transfer basket submerged in liquid propane. After freezing, the mesh basket containing the frozen sample was lifted out of the chamber, drained and transferred through several anhydrous acetone rinses at 188 K (-85 degrees C). Freeze substitution was conducted in 1% tannic acid/1% anhydrous glutaraldehyde in acetone at 188 K (-85 degrees C), followed by 1% OsO4/acetone at 277 K (4 degrees C). Freeze substitution was facilitated using a shaking table to provide gentle mixing of the substitution medium on dry ice. High quality freezing was observed in 70% of spray-frozen dinoflagellate cells and in 95% of spray-frozen cyanobacterial cells. These could be infiltrated and observed directly; however, overall ultrastructural appearance and membrane contrast were improved when the freeze-substituted cells were rehydrated and post-fixed in aqueous OSO4, then dehydrated and embedded in either Spurr's or Epon resin. Ultrastructural preservation using this ultrarapid freezing method provided specimens that were consistently superior to those obtainable in even the best comparable chemical fixations.

Animals↗

[The use of perfusion for brain fixation].

Two modifications of the apparatus for the fixation of the whole human brain are described. This apparatus can also be used for the fixation of other organs and for dead body embalming.

Brain↗

EXPERIMENTAL GLOMERULONEPHRITIS. IV. PARTICIPATION OF COMPLEMENT IN NEPHROTOXIC NEPHRITIS.

Rats with nephrotoxic serum nephritis may show fixation of complement (C') in the glomeruli during two periods. The first period occurs immediately after the injection of the antisera and extends until the host response occurs. The second period is related to the deposit of rat gamma globulin in the glomeruli presumably occurring at the time of the immune response to the heterologous nephrotoxic serum (NTS). This second period terminates about 2 to 3 weeks after injection of NTS, presumably at the time the rat stops making antibodies to the nephrotoxic gamma globulin fixed in the glomeruli. After this period, the glomerular lesion is incapable of fixing detectable amounts of circulating C' unless the antibody response to the heterologous globulin is reactivated. The immunological events which take place in the initial 2 to 3 week period appear to produce a permanent and irreparable lesion in the glomeruli leading to chronic nephritis. Rabbit NTS produces fixation of rat C' during both periods. Duck NTS shows no detectable fixation of rat C' until rat gamma globulin fixes in the glomeruli at the time of the host immune response to the heterologous nephrotoxic gamma globulin. Decomplementation of rats injected with rabbit NTS produces an amelioration of the initial period of nephrotoxic serum nephritis. The fixation of C' in the glomerular lesions was studied with the use of fluorescent antibody methods. The detection of host beta-1C globulin and gamma globulin in the glomerulus pointed to an immune reaction but not necessarily an active one. The tissue C' fixation test using kidney slices and guinea pig C' proved to be a more sensitive method of detecting tissue reactants capable of fixing C', but its relationship to in vivo events is not certain.

Animals↗

Monoclonal antibody EG2 does not provide reliable immunohistochemical discrimination between resting and activated eosinophils.

The monoclonal antibody (mAb) EG2 has been considered to identify activated eosinophils and several immunohistochemical reports of EG2+ eosinophils in various allergic and other inflammatory disorders have suggested an important pathogenic role for such cells. This study showed that cellular EG2 reactivity, both in peripheral blood and mucosal tissue preparations, depends mainly on the method of sample preparation. Nearly 100% of blood eosinophils from normal individuals were strongly EG2+ when prepared by formalin fixation, whereas only a fraction reacted in the unfixed (64%) or acetone-fixed (60%) state. A significantly increased (p < 0.03) number of EG2+ cells were likewise detected in cryo-sections of inflamed nasal mucosa after formalin fixation compared with acetone fixation. Moreover, virtually all eosinophils were EG2+ in cryo-sections of normal jejunal mucosa fixed in periodate-lysine-(0.5%) paraformaldehyde prior to freezing. Conversely, EG2 reacted only weakly, or failed to react, with many eosinophils in cryo-material not subjected to such pre-fixation, in contrast to adjacent non-eosinophilic cells which were brightly stained. Two-colour immunofluorescence consistently revealed overlapping labelling with EG2 and mAb EG1 or a polyclonal antibody to eosinophil cationic protein in sections of formalin-fixed, paraffin-embedded normal gastrointestinal mucosa. Our findings thus showed that EG2 does not provide reliable immunohistochemical discrimination between resting and activated eosinophils. When optimal pre-fixation of tissue specimens was omitted, EG2 reactivity appeared to be caused, at least in part, by leached antigen adsorbed to adjacent non-eosinophilic cells.

Adult↗

Soft-tissue alterations associated with acute, extended open reduction and internal fixation or orbital fractures.

Soft-tissue alterations associated with radical degloving of the overlying soft tissues during extended open reduction and rigid internal fixation of facial fractures involving 51 orbits in 36 patients were studied. In all patients, the blepharoplasty skin muscle flap incision was employed in conjunction with, as necessary, a gingivobuccal sulcus and coronary incisions. Patients were evaluated between 6 and 20 months after surgery. Physical examination and standardized photographs were used for assessment. Ectropion developed in 2 lids (4%), and 10 lids (20%) had increased scleral show. Thirteen of the 51 lids (25%) revealed lateral canthal displacement; all 13 lids underwent canthal stripping. Cheek pad displacement developed in 8 patients (22%), all of whom had complete maxillary degloving without soft-tissue resuspension. No patient had frontal nerve palsy. Depression in the temporal area was noted in all patients in whom the temporalis was mobilized. Remote incisions and soft-tissue degloving used for extended open reduction and internal fixation are associated with morbidity that can be minimized by meticulous technique and soft-tissue repositioning at closure.

Adolescent↗

Simultaneous morphological and stress-strain studies of the fibrous components in wet heart valve leaflet tissue.

Simultaneous morphological and stress-strain studies have been carried out on heart valve leaflet tissue maintained in its unaltered functional condition. A microtensile tissue testing device is described which inserts directly into the stage of an optical microscope fitted with a Nomarski interference contrast facility. Glutaraldehyde fixation of tissue subjected to different levels of loading reveals that the current stressed state of the collagen fibers is "frozen" in by crosslinking process, and as a consequence marked alterations in the preserved tissue properties are produced. This is shown to be relevant to the preparation of the glutaraldehyde treated heterograft heart valve. The mechanical roles of the collagen and elastin components are investigated and a "complementation" mechanism is postulated whereby the widely different mechanical properties of the two types of fibers are combined in a non-competing manner to produce a diversity of composite tissue characteristics.

Animals↗

[Histochemistry of the organs--application of histochemistry to anatomy].

Histochemistry has been developed as a science to localize chemical components of cells and tissues on histological sections by using chemical, physical and biological techniques. Many textbooks are available dealing with the methodology of histochemistry, consisting of fixation of tissues, demonstration of biochemical components such as nucleic acids, proteins, sugars, lipids, enzymes, pigments, inorganic substances and amines by means of chemical reactions (Fig. 5) or application of physical (Figs. 1-3, 6-13) and biological (Fig. 4) methods such as spectrophotometry, X-ray microanalysis, radioautography and immunohistochemistry. The methodology has been well developed to form a new science which should be given a designation "general histochemistry" as similar to general histology. On the other hand, these techniques should be applied to all the organ systems, i.e. the skeletal, muscular, circulatory, digestive (Figs. 1-6), respiratory (Figs. 7, 8), urinary (Fig. 9), genital (Fig. 10), endocrine (Fig. 11), nervous (Fig. 12), and sensory organs (Fig. 13). The results of these applications to all the organs should be collected and construct a new field of histochemistry of the organs like "histology of the organs". These results now form a new field of science which should be designated as "special histochemistry". Since the present author started the career as an anatomist and histologist in 1955, the author first aimed at the study of histochemistry by developing new chemical, physical and biological techniques such as enzyme histochemistry (Fig. 5), microspectrophotometry, autoradiography (Figs. 1-3, 6-13), cryo-techniques, immunohistochemistry (Fig. 4) and lectins in the 1950s, 1960s and 1970s. However, the author and coworkers made efforts to apply these techniques to various organ systems of humans and animals since the 1970s to the present time and collected data from all the organs including the aging process from embryos, neonates, sucklings, weanlings, adults and to senescence. The data include not only 3-dimensional structures of the organs but also the 4-dimensional features taking the time dimension into account using the radioautographic techniques by labeling cells and tissues in connection with the time lapse. The original papers published from our laboratory during these 40 years were reviewed and compiled to form a new field of science, which should be designated as histochemistry of the organs or, alternatively, special histochemistry. It is hoped that this new prospect would be well developed to form a novel system in medical science.

Aging↗

Soft-tissue distraction with a ring external fixator before centralization for radial longitudinal deficiency.

PURPOSE: To review the techniques and evaluate the use of soft-tissue distraction with a ringed fixator for radial longitudinal deficiency (RLD) before centralization. METHODS: Eight extremities in 6 patients with severe RLD were treated with ring fixator distraction followed by centralization. A clinical examination was performed and radiographic data were obtained prospectively and at an average follow-up period of 17 months. The techniques and the early objective (range of motion, position) and radiographic outcome were evaluated. RESULTS: The preoperative ring fixator accomplished an average of 16 mm of distraction and allowed the centralization procedure to be performed effectively and without tension. Clinical alignment was improved markedly. The hand-forearm angle improved from 72 degrees radial to 8 degrees ulnar after surgery. The volar carpal subluxation improved by an average of 6 mm. CONCLUSIONS: Precentralization ring fixator distraction allows the performance of a tensionless centralization procedure with good early radiographic and clinical outcome in patients severely affected with RLD. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level IV.

Adolescent↗

In situ polymerase chain reaction and cycling primed in situ amplification: improvements and adaptations.

Ethanol fixation combined with microwave pretreatment allows rapid and simple detection of signals produced by cycling primed in situ (PRINS) amplification, which uses a single primer, and in situ polymerase chain reaction (ISPCR) in intact cells. After thermal cycling, signals remain as discrete subnuclear spots in the region of amplification and are clearly distinguishable from non-specific background labelling. These methods are applicable to routine blood smears, even after Giemsa staining or immunocytochemistry, and cellular morphology is retained. Chromosome enumeration by cycling PRINS is demonstrated using primers for repeat DNA sequences, whilst single copy sequence detection is demonstrated using bcl-2, CFTR and chromosome 21 specific primer pairs in ISPCR. We show that ethanol fixation supports efficient extension of cycling PRINS products to approximately 550 bp using up to 70 rounds of thermal cycling.

Azure Stains↗

Diethylpyrocarbonate and benzoquinone vapour fixation for immunofluorescence studies of non-hormone protein in frozen dried tissues.

The use of gaseous (DEPC, BOV) postfixation of frozen-dried tissues for the fixation of non-hormone proteins was systematically studied. The fixation ability was tested on the "protein droplet model" i.e. the protein droplets formed in mouse liver after intravenous injection of bovine serum albumin (BSA). 1. There is no difference in the fixation ability for BSA between DEPC and BQV. 2. Both fixatives yield a very poor fixation of BSA in frozen-dried livers. In consequence, this protein is already extracted during section mounting and incubation for immunofluorescent tracing causing a strong substantial loss. 3. Remaining protein traces, however, are still immunoreactive indicating that DEPC and BQV fixation does not affect the antigenicity in considerable extent.

Animals↗

Calcium-dependent ATPase unlike ecto-ATPase is located primarily on the luminal surface of brain endothelial cells.

Numerous cytochemical studies have reported that calcium-activated adenosine triphosphatase (Ca2+-ATPase) is localized on the abluminal plasma membrane of mature brain endothelial cells. Since the effects of fixation and co-localization of ecto-ATPase have never been properly addressed, we investigated the influence of these parameters on Ca2+-ATPase localization in rat cerebral microvessel endothelium. Formaldehyde at 2% resulted in only abluminal staining while both luminal and abluminal surfaces were equally stained following 4% formaldehyde. Fixation with 2% formaldehyde plus 0.25% glutaraldehyde revealed more abluminal staining than luminal while 2% formaldehyde plus 0.5% glutaraldehyde produced vessels with staining similar to 4% and 2% formaldehyde plus 0.25% glutaraldehyde. The abluminal reaction appeared unaltered when ATP was replaced by GTP, CTP, UTP, ADP or when Ca2+ was replaced by Mg2+ or Mn2+ or p-chloromercuribenzoate included as inhibitor. But the luminal reaction was diminished. Contrary to previous reports, our results showed that Ca2+-specific ATPase is located more on the luminal surface while the abluminal reaction is primarily due to ecto-ATPase. The strong Ca2+-specific-ATPase luminal localization explains the stable Ca2+ gradient between blood and brain, and is not necessarily indicative of immature or pathological vessels as interpreted in the past.

Adenosine Diphosphate↗