Serial sectioning of tissues in glycol methacrylate by supplementary embedding in a paraffin-plastic matrix.
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Acrylates↗
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A rapid method for preparing undecalcified sections of bone for autoradiographic investigation with short-lived radionuclides.
To prepare sections of undecalcified bone suitable both for autoradiography with short-lived radionuclides such as 99m-technetium (t 1/2 = 6 hr) and for normal histology, rapid processing is necessary. By modifying the routine technique of embedding in plastic, sections can be obtained within 6 hours. The most important modification concerns the temperature used for the different steps in the process. The procedure has been used to localize 99mTc labeled methylene diphosphonate for skeletal scintigraphy.
Animals↗
A method to identify microinjected nephrons of rat.
This paper describes a technique for identifying individual nephrons that have been subjected to micropuncture. The general location of the nephron is marked on the surface of the kidney by implanting two micropipette tips on opposite sides of it two or three tubule diameters away. The tubule itself is marked by the injection into the lumen of a tracer material, for purposes of this account, a suspension of E. coli. After perfusion fixation the kidneys are removed and a block of tissue containing the extrapapillary portion of the nephron is excised. This block is cut into thin slices parallel to the surface of the kidney; these are embedded in plastic for subsequent sectioning. On sectioning, the marker material makes the nephron in question readily discernible under the microscope. A major advantage of this technique is that it allows the tubule of interest to be located as much as 48 hours later.
Animals↗
A new technique facilitating studies of scant cell specimens.
A simple method is described by which multiple cytological and cytochemical studies can be done on a clinical sample that contains relatively few cells. The cells are concentrated by centrifugation. The cell pellet is fixed, frozen and embedded in plastic. Thin (2-microns) sections are cut from the plastic. Thus, each cell may appear in several sections and many slides can be made from a single specimen. The advantages of this method over cytospins and Millipore filter preparations of cell suspensions are optimal utilization of all cells, excellent morphological and immunological preservation and ease and reproducibility of this technique.
Histocytochemistry↗
Combined lectin binding and PAS/alcian blue staining in glycol methacrylate sections.
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Alcian Blue↗
Improved gold chloride procedure for nerve staining in whole mounts of rat corneas.
The purpose of this study was to modify the gold chloride procedure for studies of total innervation in corneal whole mounts to provide a decrease in nonspecific background staining and to eliminate the progressively deteriorating stain quality of standard gold chloride techniques. Modifications included use of cryoprotective agents, mechanical removal of Descemet's membrane-endothelium complex prior to fixation, treatment with alpha amylase, and halting the reduction of gold chloride to metallic gold using Kodak rapid fixer with hardener. Rat corneas were stored at -70 C in O.C.T. compound. The Descemet's membrane-endothelium complex was removed after thawing, and corneas were fixed in 4% NaPO4-buffered paraformaldehyde with 8% sucrose. Fixed corneas were incubated in NaPO4-buffered saline containing alpha amylase, placed in 100% lemon juice, then in 1% gold chloride solution, transferred to glacial acidic acid, placed in rapid fixer, rinsed in NaPO4-buffered saline, and dehydrated in graded alcohols. Flat mounts of whole corneas were examined using contralateral corneas as controls. Freezing corneas in O.C.T. compound, removal of the Descemet's membrane-endothelium complex, and treatment with alpha amylase reduced non-specific background staining compared to controls. Treatment with Kodak rapid fixer prevented the deterioration of staining quality for at least 8 months. These improvements allow the gold chloride technique to be used with immunohistochemical procedures where the reaction products would be obscured by background staining.
Animals↗
The influence of antihypertensive treatment on the renal arterial structure in spontaneously hypertensive rats. A morphometric study.
Spontaneously hypertensive rats (SHR) and stroke-prone spontaneously hypertensive rats (SHRSP) were treated with a combination of a beta 1-blocker (metoprolol) and a Ca++-antagonist (felodipine) from 1 to 4 months or 4 to 6 months of age. The renal arterial trunks as well as more distal parts of the renal arterial bed were fixed by immersion and embedded in plastic. The media cross-sectional area and the length of the internal elastic membrane were measured on cross-sectioned arteries. The media thickness, luminal radius and the ratio between media thickness and luminal radius (m/r ratio) were then calculated for a standardized condition, assuming a smooth and circular internal elastic membrane, in which the arteries were compared. The m/r ratio was markedly reduced in the most proximal as well as in more distal arterial segments of the treated animals when compared with untreated rats of corresponding age and category. The quotient was somewhat reduced also when compared with normotensive controls (WKY) although the systolic blood pressure in younger treated rats was not fully normalized. The results may suggest that the present treatment influences the arterial walls not only by reducing the pressure load but also through pressure-independent mechanisms.
Animals↗
Morphometric effect of prostaglandin E1 and F2 alpha on lactating bovine mammary tissue in vitro.
Mammary explants from six lactating cows were incubated for .17, 4, 8, and 12 h in medium containing prostaglandin E1 or prostaglandin F2 alpha tromethamine salt at 0, 1, 10, or 50 micrograms/ml to determine if prostaglandins alter tissue structure. Explants were fixed, dehydrated, embedded in plastic resins, and sectioned at .5 to 1.0 mu. Tissue area was partitioned by light microscopy into normal, damaged, or debris epithelial; normal or debris lumenal; or stromal areas. All tissue samples exhibited signs of deterioration as incubation progressed. Prostaglandin E1 treatment maintained more secretory epithelium and resulted in less epithelial debris and lumenal debris than controls. Prostaglandin F2 alpha-treated tissue had less epithelial debris and normal lumenal area than tissue receiving no prostaglandin during the limited incubation. The three concentrations of prostaglandins studied did not identify optimal prostaglandins for mammary tissue incubated but indicated concentrations below 1 microgram prostaglandin E1 or F2 alpha/ml should be studied. The response of mammary tissue to prostaglandin was affected by donor milk production. Increases of normal epithelial area were correlated with decreases of damaged and debris areas. Prostaglandins E1 and F2 alpha appeared to be beneficial to healthy mammary tissue incubated under limited conditions.
Alprostadil↗
Correlation between histopathological findings in C-5 and C-6 nerve stumps and motor recovery following nerve grafting for repair of brachial plexus injury.
OBJECT: Proximal spinal nerve stumps were used as donor sites for grafts to repair brachial plexus traction lesions. The quality of the stumps was assessed histologically, and its correlation with the strength attained in the target muscle was studied. METHODS: Four histopathological parameters in frozen tissue sections of 31 C-5 or C-6 nerve stumps were examined by a neuropathologist. The total quantity of myelin was compared with normal values. Also, thick myelinated fibers, fibrosis, and misdirected axons were assessed. Stumps embedded in plastic were used in a morphometric study of myelinated fiber profiles. The fiber density, mean size, and size distribution in five donor stumps were determined; three normal C-5 spinal nerves obtained at autopsy served as controls. Finally, the relative area occupied by fiber profiles and interspace was computed. Linear regression was used as a multivariate analysis, adjusting the outcome of surgical repair for effects of age, interval between trauma and surgery, and graft length. Histopathological examination showed that the total quantity of myelin in donor stumps used for biceps muscle reinnervation was considerably reduced. On morphometric examination the fiber density did not differ significantly between stumps obtained in patients and control stumps obtained at autopsy. However, a significant reduction of the area occupied by myelinated fibers was measured: from 46% in controls to 13% in patients (p < 0.0001). Likewise, a significant reduction was found in the mean fiber size: from 7.4 microm in controls to 3.7 microm in patients (p < 0.0001). The relationship between the myelin quantity in the proximal stump and the grade of biceps muscle recovery was statistically significant (p = 0.02). From the 95% confidence interval it was concluded that the estimated effect of a mean increase of myelinated fibers by 25% almost equals an increase in recovery of one point on the Medical Research Council scale (grade range 0-5). CONCLUSIONS: Both histopathological and morphometric examination showed a reduction of the quantity of myelin in C-5 or C-6 stumps used as donor sites for grafts. The amount of myelin is significantly correlated with biceps muscle function after nerve grafting. Because it is possible to assess the quantity of myelin by intraoperative examination of frozen sections, this correlation is potentially useful in the decision-making process of whether to use stumps for grafting or to use nerve transfer procedures to restore biceps muscle function.
Adolescent↗
Increased size and biconcavity in red blood cells of obese-hyperglycaemic mice.
Blood from non-inbred obese-hyperglycaemic ob/ob-mice or normoglycaemic controls was fixed in glutaraldehyde and embedded in plastic on glass slides. In vertically oriented red blood cells (RBCs) the diameter, central thickness, and toroidal thickness were measured at the diametrical cross section. For each RBC, the area, volume, and cross-sectional profile were calculated and used to analyze the mechanical properties of the corpuscle. In both types of mice, the diameter correlated positively with the central thickness and negatively with the toroidal thickness, suggesting a variation not only in size but also in biconcavity; the smaller the diameter, the more biconcave the disc. However, ob/ob-mouse RBCs were both larger and more biconcave than those in control mice. These differences in size and shape are suggested to explain why ob/ob-mouse RBCs exhibit a decreased deformability in filtration experiments.
Animals↗
Thallium-201 radioactive implant induced X-ray emission scanning of stable iodine distribution in thyroid--phantom experiment.
A new method has been developed for imaging the thyroid gland by the use of 201Tl radioactive implant induced X-ray emission (RIXE). The thyroid phantom was made from two cylindrical tubes embedded in plastic neck phantom. Each tube consisted of stable iodine and 201Tl radioactive source in 10 ml water solution. Some photopeaks in the energy range from 20 to 200 ke V were scanned along a horizontal axis by the collimated Ge detector with high energy resolution. The distribution on the horizontal axis was obtained for the generated I K alpha-ray and some primary 201Tl radiations. The 201Tl RIXE scanning can provide information about the distribution of iodine with 201Tl as well as 201Tl distribution in the thyroid gland. The effectiveness of the 201Tl RIXE technique as a thyroid scanning method is discussed.
Iodine↗
Plastination with silicone method S 10--monitoring and analysis causes of failure.
Plastination is in some cases unsuccessful. The goal of this work was to monitor, to describe and to analyse the reasons of S10 plastination method failure. We prepared the silicone-impregnated specimens using the standard silicone method S 10. The causes of bad preparation are numerous. Usual defects produced during plastination process are the changes in the bulk, the changes in the colour and other visible defects (e.g. deformations, spots on the organs surface). The frequent reasons for these defects are: unsuitable temperature, using of old bad fixed formaldehyde specimens and too long gas-curing procedure. The knowledge of reasons of unsuccessful plastination is important condition for achievement the good results.
Histological Techniques↗
Histopathology of experimental Chagas disease in NMRI-mice. A long term study following paw infection.
NMRI-mice were infected subcutaneously with T. cruzi Brazil and the pathohistological findings in 17 organs at different times after infection are described. The paw was chosen as injection site, for, due to the great variety of tissues found in a single histological section, the first reactions between host and parasite are best studied here. For this purpose the complete paw was embedded in plastic and sectioned longitudinally. After infection with 5 X 10(4) parasites a shift of parasitism from the initial host cells (macrophages) to the neighbouring muscle cells was observed. This occurred on the 9th day after infection. On the 18th day a generalized parasitism of organs containing muscle had developed, especially of myocardium and alimentary tract. Destruction and inflammation of heart muscle was the most important consequence with respect to mortality. The autonomous nervous system of heart and alimentary tract was involved, although not selectively. Liver and spleen played no role as host tissues. After infection with 10(2) or 10(3) parasites specific alterations in the animals surviving the acute phase were not observed from the 60th to 201st day. A perivenous encephalitis without cerebral parasitism was found in about one half of the experimental animals. It does not correspond to the known 'Chagas encephalitis' and is for the present defined as parainfectious.
Animals↗
The vascularization of the os calcaneum and the clinical consequences.
This study was conducted to analyze extraosseous and intraosseous vascularization of the os calcaneum and to elucidate possible clinical manifestations. The arteries of 13 lower leg and foot specimens of human cadavers were injected with a polymer and subjected to maceration or were embedded in plastic. The examination revealed that 45% of the bone is vascularized via medial arteries and 45% via lateral arteries, whereas the remaining 10% is supplied by the sinus tarsi artery. From the medial side, two or three vessels branch off the posterior tibial artery, penetrate the calcaneus below the sustentaculum, and supply the medial part of the posterior joint. The lateral calcaneal artery normally is a branch from the posterior tibial artery. In two of 13 specimens, this lateral supply comes from the peroneal artery. The medial and lateral intraosseous arterial supply for the calcaneus is equal. Inside the bone there is a water-shed zone where the medial and lateral arterial supply meet in the midline. Only 10% of the blood flow is supplied by vessels in the sinus tarsi. Clinically, interruption of the lateral calcaneal artery during the conventional lateral surgical approach for a calcaneus fracture may result in ischemic bone necrosis. The lateral calcaneal artery could supply a local microvascular flap to cover soft tissue defects of the heel. A compartment syndrome after a calcaneus fracture may be caused by bleeding from the medial calcaneal arteries into the quadratus plantae compartment.
Adult↗
Motor and sensory demyelinating mononeuropathy multiplex (multifocal motor and sensory demyelinating neuropathy): a separate entity or a variant of chronic inflammatory demyelinating polyneuropathy?
We report 16 patients with motor and sensory demyelinating mononeuropathy multiplex (MSDMM) or multifocal motor and sensory demyelinating neuropathy (MMSDN). These patients had the clinical pattern of motor and sensory mononeuropathy multiplex, electrophysiological evidence of demyelination including conduction block, and segmental demyelination in the sural nerve biopsy. Sixty per cent of patients had high CSF protein. Eighty per cent of patients showed good responsiveness to steroid treatment. Unlike multifocal motor neuropathy (MMN), MSDMM is characterized by a shorter course, sensory deficits and sensory nerve conduction abnormalities, absence of GM1 antibody in most patients tested, and a good response to steroid therapy. We believe that MSDMM represents a variant of chronic inflammatory demyelinating polyneuropathy (CIDP) and an intermediate link between CIDP and MMN.
Adolescent↗
Histologic changes in the adrenal cortex from young rats following spaceflight.
BACKGROUND: Potential stresses associated with spaceflight include microgravity, acceleration and deceleration forces, a crowded environment and re-adaptation to normal gravity after landing. HYPOTHESIS: We hypothesized that spaceflight would result in histological changes in the adrenal glands of young rats. METHODS: Six week old male rats were group-housed in an Animal Enclosure Module (AEM) for a 17 d shuttle flight (STS-78). Ground-based controls included a baseline group, an AEM-housed group and a vivarium group. Adrenal glands were collected from 4-6 hours after flight, fixed, embedded in plastic and sections prepared for light microscopy. RESULTS: The adrenals from the baseline and vivarium groups had normal histological features. Some changes in the adrenal cortices from the ground-based AEM group included greater parenchymal cord-like formation. The adrenal weights and width of the zona fasciculata were greater in the flight group than the controls. There were also increased parenchymal cord-like formation with better demarcation of the vascular sinusoids in the zona reticularis and zona fasciculata, greater depletion of cytoplasmic lipid vacuoles, and an increased nuclear volume of the cells in the zona fasciculata when compared with the controls. CONCLUSIONS: The adrenal changes in the ground-based AEM animals may be attributed to the confined space in the AEM. The adrenal enlargement and the histological changes observed in the flight animals may be attributed to spaceflight and possibly re-entry in addition to possible confinement stress in the AEM.
Adrenal Cortex↗
Transparent tooth model system. An aid in the study of root canal anatomy.
Clearing techniques of tooth have long since been advocated in the demonstration of root canal anatomy. We have compared the efficacy of various clearing agents such as Xylene, Benzene, Methyl salicylate and Eugenol, using 40 maxillary second premolars as experimental subjects. We have further tried to select a suitable dye for the demonstration of root canal anatomy and have compared the efficacy of various mounting media such as D.P.X. medium, Canada balsam and Commercial plastic dissolved in benzene, in preserving the cleared state. Results of our study indicate that Eugenol is a superior clearing agent and that oil-based dyes are better suited for root canal demonstration. Canada balsam is the most effective mounting media and D.P.X. medium has been found to serve both as a clearing agent and as a mounting media. We have introduced a miniature museum jar technique, for preserving the transparency permanently. The Transparent Tooth Model System presented here, thus serves as a much simpler tool, in the study of root canal anatomy, three dimensionally.
Benzene↗
Histological techniques and microscopic analysis of biological agents for preservation of human bone remains.
Microscopy and histology techniques can be applied to morphological study of fungi and bacteria contaminating ancient human osteological remains. Undecalcified samples are cut with a diamond rotary blade microtome and an original technique was applied using adhesive tape to prevent damage to the bone surface during sectioning. We used light microscopy, polarized light microscopy, and epi-illumination fluorescence systems. Common dyes can be applied to 80 microm sections using classic staining techniques to reveal the architecture of bone and the presence of infecting biological agents.
Bone and Bones↗