Radioprotective effects of melatonin against varying dose rates on radiotherapy-induced salivary gland damage scintigraphy findings

1974 ◽

Vol 32 ◽

pp. 148-149

Author(s):

D. E. Philpott ◽

A. Takahashi

Keyword(s):

Skeletal Muscle ◽

Endothelial Cells ◽

Salivary Gland ◽

Carotid Artery ◽

Basement Membrane ◽

Coronary Vessels ◽

Ruthenium Red ◽

E Coli ◽

Old Rats ◽

The Brain

Two month, eight month and two year old rats were treated with 10 or 20 mg/kg of E. Coli endotoxin I. P. The eight month old rats proved most resistant to the endotoxin. During fixation the aorta, carotid artery, basil arartery of the brain, coronary vessels of the heart, inner surfaces of the heart chambers, heart and skeletal muscle, lung, liver, kidney, spleen, brain, retina, trachae, intestine, salivary gland, adrenal gland and gingiva were treated with ruthenium red or alcian blue to preserve the mucopolysaccharide (MPS) coating. Five, 8 and 24 hrs of endotoxin treatment produced increasingly marked capillary damage, disappearance of the MPS coating, edema, destruction of endothelial cells and damage to the basement membrane in the liver, kidney and lung.

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Ovarian Dysfunction in Fetally Irradiated Beagles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100080717 ◽

1977 ◽

Vol 35 ◽

pp. 658-659

Author(s):

T. M. Seed ◽

M. H. Sanderson ◽

D. L. Gutzeit ◽

T. E. Fritz ◽

D. V. Tolle ◽

...

Keyword(s):

Gamma Rays ◽

Low Dose ◽

Long Term Effects ◽

Ovarian Dysfunction ◽

Dose Rates ◽

Highly Sensitive ◽

Microscopic Evaluation ◽

Ovarian Pathology ◽

Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

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Electron Beam Damage of Biomolecules Assessed by Energy Loss Spectroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069855 ◽

1978 ◽

Vol 36 (3) ◽

pp. 61-69

Author(s):

M. Isaacson ◽

M.L. Collins ◽

M. Listvan

Keyword(s):

Electron Microscopy ◽

Radiation Damage ◽

Structural Integrity ◽

Analytical Electron Microscopy ◽

High Dose ◽

Dose Rates ◽

Special Cases ◽

Analytical Electron ◽

Atom Migration ◽

Beam Damage

Over the past five years it has become evident that radiation damage provides the fundamental limit to the study of blomolecular structure by electron microscopy. In some special cases structural determinations at very low doses can be achieved through superposition techniques to study periodic (Unwin & Henderson, 1975) and nonperiodic (Saxton & Frank, 1977) specimens. In addition, protection methods such as glucose embedding (Unwin & Henderson, 1975) and maintenance of specimen hydration at low temperatures (Taylor & Glaeser, 1976) have also shown promise. Despite these successes, the basic nature of radiation damage in the electron microscope is far from clear. In general we cannot predict exactly how different structures will behave during electron Irradiation at high dose rates. Moreover, with the rapid rise of analytical electron microscopy over the last few years, nvicroscopists are becoming concerned with questions of compositional as well as structural integrity. It is important to measure changes in elemental composition arising from atom migration in or loss from the specimen as a result of electron bombardment.

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Electron-diffraction studies in synthetic polymer materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075579 ◽

1983 ◽

Vol 41 ◽

pp. 362-365

Author(s):

D.T. Grubb

Keyword(s):

Electron Diffraction ◽

Synthetic Polymer ◽

Polymer Materials ◽

Crystallographic Structure ◽

High Dose ◽

Electron Dose ◽

Dose Rates ◽

First Case ◽

Diffraction Patterns ◽

The Many

Diffraction studies in polymeric and other beam sensitive materials may bring to mind the many experiments where diffracted intensity has been used as a measure of the electron dose required to destroy fine structure in the TEM. But this paper is concerned with a range of cases where the diffraction pattern itself contains the important information.In the first case, electron diffraction from paraffins, degraded polyethylene and polyethylene single crystals, all the samples are highly ordered, and their crystallographic structure is well known. The diffraction patterns fade on irradiation and may also change considerably in a-spacing, increasing the unit cell volume on irradiation. The effect is large and continuous far C94H190 paraffin and for PE, while for shorter chains to C 28H58 the change is less, levelling off at high dose, Fig.l. It is also found that the change in a-spacing increases at higher dose rates and at higher irradiation temperatures.

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Electron Beam-Induced Mass Loss in Freeze-Dried Tissue and Protein Samples

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010011917x ◽

1985 ◽

Vol 43 ◽

pp. 470-471

Author(s):

M.E. Cantino ◽

M.K. Goddard ◽

L.E. Wilkinson ◽

D.E. Johnson

Keyword(s):

Electron Beam ◽

Salivary Gland ◽

Mass Loss ◽

Counting Rate ◽

Dose Dependence ◽

X Ray ◽

Large Samples ◽

Freeze Dried ◽

Muscle Homogenate ◽

Large Muscle

Quantification in biological x-ray microanalysis depends on accurate evaluation of mass loss. Although several studies have addressed the problem of electron beam induced mass loss from organic samples (eg., 1,2). uncertainty persists as to the dose dependence, the extent of loss, the elemental constituents affected, and the variation in loss for different materials and tissues. in the work described here, we used x-ray counting rate changes to measure mass loss in albumin (used as a quantification standard), salivary gland, and muscle.In order to measure mass loss at low doses (10-4 coul/cm2 ) large samples were needed. While freeze-dried salivary gland sections of the required dimensions were available, muscle sections of this size were difficult to obtain. To simulate large muscle sections, frog or rat muscle homogenate was injected between formvar films which were then stretched over slot grids and freeze-dried. Albumin samples were prepared by a similar procedure. using a solution of bovine serum albumin in water. Samples were irradiated in the STEM mode of a JEOL 100C.

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