Fluorescent location of rat leukaemia cells in resin sectionsCells which have the ability to migrate are associated with a recently described proteolytic enzyme (Steven and Al-Ahmad, 1983) referred to as guanidinobenzoatase (GBase).GBase degrades fibronectin and in particular the peptide GlyArgGlyAsp, which is thought to link fibronectin to cell surfaces (Pierschbacher and Ruoslahti, 1984). This activity may explain why migratory cells possess this unusual enzyme. GBase is inhibited by 9-aminoacridine which stacks at the active centre leading to intense fluorescence of cells possessing this enzyme (Steven et al., 1985). We have employed 9-aminoacridine to locate invading leukaemia T-cells in LKB 2218-500 historesin sections of formalin-Jined rat kidney tissue obtained from animals with T-cell lymphoblastic leukemia (Dibley et al., 1975; Jackson et al., 1984). Historesin sections I pm thick were stained with 9-aminoacridine ( I O v 3~) for 5 min, then washed with isotonic saline for 30 sec prior to fluorescent microscopy in a Leitz Orthoplan microscope employing UV illumination. The leukemia cells exhibited yellow surface fluorescence (Fig. I ) whilst the surrounding host tissue was very weakly stained. The lumen of the tubules appeared blue and did not bind 9-aminoacridine. Individual leukaemia cells can be located by this technique. Much of the yellow fluorescence of 9-aminoacridine staining was lost during photography; this problem was overcome by co-stacking propidium iodide on the previously stacked 9-aminoacridine, which resulted in cells with pink sulface fluorescence and better photographic contrast . For this putpose, the 9-aminoacridine-stained slides were dipped in propidium iodide (6 x 1 0 -5~) for I min and washed with water for I0 sec prior to microscopic examination using W illumination. Figure 2 shows clusters of leukemia cells surrounding kidney tubules whilst Figure 3 Figure 4 Figure 5, whilst Figure 6 shows a mass of leukaemia cells and a partially destroyed kidney parenchyma. shows individual leukaemia cells in the intertubular spaces. The staining of circulating leukaemia cells in the kidney vasculature is demonstrated in together with heavy infiltration by leukaemia cells in the intertubular tissue. Accumulation of leukemia cells within and around a glomerulus is shown inAlthough propidium iodide is conventionally used as a nuclear stain, we have utilized the prior stacking of 9aminoacridine on the cell surface of leukemia cells to co-stack propidium iodide, obtaining cells with pink fluorescent surfaces (see arrows in Figs. 2, 5 and 6). Historesin sections were employed to preserve the cell structure by preventing shrinking; this is best illustrated in Figures I , 2, 4 and 5, where the irregular surface of the leukemia cells is clearly defined by the yellow or pink surface fluorescence. We believe that chemofluorescent probes can be of value in locating small clusters of leukemia cells and even isolated cells. These cells might otherwise escape identification by conventional staining techni...
Penelitian ini menginvestigasi sifat kekerasan dan keausan kampas rem komposit hibrida. Komposit hibrida berbasis penguat adalah serbuk tempurung Kelapa dan alumina dengan matriks phenolic resin. Benda uji diproduksi menggunakan hot press pada temperatur sinter bervariasi dari 200oC, 250oC dan 300oC. Tujuan penelitian adalah menentukan tingkat kekerasan, laju keausan dan koefisien gesek dari komposit hibrida. Pengujian dilakukan dengan menggunakan pin-on-disk dan Vikers berdasarkan standar masing-masing ASTM E-92 dan ASTMG99-95a. Hasil pengujian ditunjukkan temperatur sinter telah signifikan menurunkan koefisien gesekan, walaupun pada benda uji A dengan temperatur sinter 200oC masih lebih tinggi dari benda uji control sebesar 3.54%. Kemudian, nilai kekerasan HV untuk komposit hibrida pada temperatur sinter 300oC adalah 9.3% lebih tinggi dari pada kontrol. Kesimpulan adalah komposit hibrida dengan komposisi 40% serbuk tempurung kelapa dan 20% alumina potensial diaplikasikan untuk bahan alternatif kampas rem kendaraan bermotor. This research investigates the hardness and wear behavior of hybrid composite brake pad. Hybrid composite was manufactured base on particles coconut cell and alumina reinforced and phenolic resin matrix. The specimens were produced by using the hot press according to temperatures variation of 200oC, 250oC and 300oC. The research purpose to determine hardness ability, wear rate, and friction coefficient of hybrid composites. Pin-on-disk and Vickers test have been employed according to the ASTM E-92 dan ASTMG99-95a, respectively. The result shows that sintering temperature have been significant decreased friction coefficient, while on specimen A with 200oC sinter temperature has 3.54% higher than control specimen. In addition, the hardness (HV) number of hybrid composite on 300oC sinter temperatures has 9.3% higher than control. Conclusion, hybrid composite with composition 40% coconut cell particles and 20% alumina has potential as alternative material of the vehicle brake pad application.
Epithelial cell surfaces possess a trypsin-like protease, referred to as guanidinobenzoatase (GB). The cytoplasm of these cells contains an extractable protein (I) which recognises the cell surface GB by forming an enzyme-inhibitor complex (GB-I). Rhodamine-agmatine (Rh-Agm) was designed as a red fluorescent probe, directed to the active centre of GB, which can be used to locate cells with GB, employing fluorescence microscopy. Rh-Agm has a high affinity for GB and will displace I from GB-I on the surfaces of cells in frozen sections. Rh-Agm has been used to displace I from immobilised GB-I complexes on the surface of cultured colonic carcinoma cells in an affinity procedure aimed at purifying the inhibitors of GB obtained from cultured carcinoma cells. These inhibitors have been tested on protected frozen sections of normal colon and carcinoma of the colon, the formation of GB-I complexes being followed by a second yellow fluorescent probe which competes for the active centre of GB. The study of the protein-protein interactions to form GB-I has been facilitated by employing two synthetic fluorescent inhibitors of GB with differing affinities for GB and different fluorescent properties. The use of sections of tissue in this study has enabled a sequence of reactions to be carried out on the same cell surface GB, such that reversible inhibition reactions can be quickly demonstrated and recorded by fluorescence microscopy.
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