Influence of Platelet Inhibitory Drugs on the Thrombogenicity of Dacron Arterial Grafts Perfused in an Artificial Circulation

1979 ◽  
Author(s):  
C.N. McCollum ◽  
S.M. Rajah ◽  
M.J. Crow ◽  
R.C. Kester

The effect of Acetyl Salicylic Acid (ASA), Dipyridamole (DPM) and in combinations on the response of platelets to woven Dacron perfused in an artificial circulation was investigated. Circuits were perfused by heparinised blood donated by 6 volunteers after each had taken: -1) No drugs 2) ASA 300mg tds 3) DPM 100mg qds 4) ASA 300mg + DPM 75mg tds 5) ASA 80mg + DPM 75mg tds 6) ASA 80mg tds, for 1 week. Bleeding times were performed prior to each donation. Platelet functions were estimated during perfusion. Each grafts surface was examined by scanning electron microscopy (SEM) at the end of perfusion.Platelet inhibition by low dose ASA + DPM was accompanied by less extension of bleeding time, and we suggest that such combination may protect patency in Dacron grafts at risk.

2015 ◽  
Vol 1 (1) ◽  
pp. 68
Author(s):  
Jassem G Mahdi ◽  
Ahmed J Mahdi ◽  
Eamon J G Mahdi ◽  
Asma Abdulsatar ◽  
Ali J Mahdi ◽  
...  

<p class="BodyText1">Hydroxybenzoate (HB) compounds have shown to modulate the morphology in human fibrosarcoma HT-1080 cells. The changes in HT-1080 cells showed marker signs of apoptosis, which included the condensation of nucleus, cell round, blebbing and the formation of apoptotic bodies. The different stages of apoptosis were assessed microscopically using different staining and immunohistochemical techniques, as well as scanning electron microscopy. In addition, HB compounds increased the expression of caspase-3, which is closely associated with the development of the modulation in HT-1080 cells that are undergoing the programmed cell death. Both acetyl salicylic acid (ASA) and HBZn compounds were dose and treatment duration dependent.</p>


1979 ◽  
Author(s):  
A.F. Penny ◽  
M. J. Crow ◽  
S. M. Rajah ◽  
R.C. Kester

The interaction of Dipyridamole (DPM) and Acetyl Salicylic Acid (ASA) on volunteers was investigated. ASA was given in single doses (multiples of 60mg) at 2 week intervals. DPM (multiples of 25 mg) was given tds for 2 days with a single dose of DPM and ASA on the morning of day 3. Bleeding time and platelet functions were performed 2 hours after each dose. ASA 300mg maximally inhibited aggregation, adhesion and PF4 release. Lower doses of ASA gave significant reductions in collagen aggregation at 120 mg, adhesion at 180mg and PF4 at 240mg. DPM 25mg tds produced reductions in collagen aggregation, adhesion and PF4. Maximal inhibition of platelet function without alteration in bleeding time was achieved by 50mg tds DPM + 180mg ASA or 75mg tds DPM + 120mg ASA. Bleeding time was normal with ASA 120mg, 180mg; prolonged at 300mg and 1000mg and tending to be normalised by 2g. Addition of DPM 75mg tds at each dose of ASA made no alteration in bleeding time. There was a cumulative effect of ASA on bleeding time. Combined DPM mg tds and low dose ASA present a balanced anti thrombotic regimen probably both inactivating thromboxane A2 production and enhancing prostacyclin activity. This dose combination is worthy of evaluation as an additional group, in trials.


Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.


Author(s):  
P.J. Dailey

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.


Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).


Author(s):  
Ronald H. Bradley ◽  
R. S. Berk ◽  
L. D. Hazlett

The nude mouse is a hairless mutant (homozygous for the mutation nude, nu/nu), which is born lacking a thymus and possesses a severe defect in cellular immunity. Spontaneous unilateral cataractous lesions were noted (during ocular examination using a stereomicroscope at 40X) in 14 of a series of 60 animals (20%). This transmission and scanning microscopic study characterizes the morphology of this cataract and contrasts these data with normal nude mouse lens.All animals were sacrificed by an ether overdose. Eyes were enucleated and immersed in a mixed fixative (1% osmium tetroxide and 6% glutaraldehyde in Sorenson's phosphate buffer pH 7.4 at 0-4°C) for 3 hours, dehydrated in graded ethanols and embedded in Epon-Araldite for transmission microscopy. Specimens for scanning electron microscopy were fixed similarly, dehydrated in graded ethanols, then to graded changes of Freon 113 and ethanol to 100% Freon 113 and critically point dried in a Bomar critical point dryer using Freon 13 as the transition fluid.


Author(s):  
Jane A. Westfall ◽  
S. Yamataka ◽  
Paul D. Enos

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).


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