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Biomedical subjects

M G Bond

Publications and source records attributed to M G Bond.

At least 91 records · Page 5Linked to original sources
PubMed1982

Detection of early atherosclerosis in M. fascicularis with transcutaneous ultrasonic measurement of the elastic properties of the common carotid artery.

The elastic properties of 22 common carotid arteries from 13 male cynomolgus monkeys (M. fascicularis) that were fed either a high cholesterol (test) diet or a standard monkey chow (control) diet for 18 months were measured noninvasively with 5 MHz ultrasound. A B-mode image of the artery was obtained with a 32-element linear array transducer, and a single line of video ultrasonic information was selected for tracking the echoes from the adventitial side of the near wall to the lumen-intima interface of the far wall. This technique measured lumen diameter plus anterior wall thickness. The diastolic diameter (Dd) (mean +/- SEM) of the test arteries was slightly larger than controls (2.9 +/- 0.1 vs 2.5 +/- 0.1 mm), whereas the fractional diameter change from diastole to systole (DeltaD/Dd, where DeltaD = diameter change) was slightly less (0.062 +/- 0.010 vs 0.082 +/- 0.011). Direct subclavian artery pulse pressure (DeltaP) in the test animals (63 +/- 4 mm Hg) was significantly greater than in the controls (41 +/- 2 mm Hg), whereas there was no difference in diastolic pressure (85 +/- 3 vs 81 +/- 2), respectively. The pressure-strain elastic modulus Ep = (DeltaP/DeltaD) Dd was significantly greater in the test monkeys (182 +/- 33 kPa) than in the controls (73 +/- 9 kPa). Morphometric analysis of atherosclerosis revealed more connective tissue and intra- and extracellular lipids in the test arteries than in the controls. Based on the average of three cross-sections equally spaced along each common carotid artery, the intimal area and the maximal intimal thickness averaged 0.89 +/- 0.16 mm2 and 0.26 +/- 0.04 mm for the test monkeys compared to negligible intimae from the controls. Medial area also was significantly greater in the test monkeys (0.71 +/- 0.03 mm2) compared to controls (0.57 +/- 0.04 mm2). Percentage stenosis defined as intimal area/IEL area, where IEL area is that within the internal elastic lamina, showed the test arteries to have 30 +/- 5% stenosis compared to 0% for the controls. However, dilatation appeared to compensate for any loss in lumen area due to intimal thickening. In this study, significant carotid artery stiffening associated with diet-induced atherosclerosis is demonstrated. This noninvasive technique may be useful in pediatrics and in preventive medicine for the detection of arterial stiffening associated with early progressive atherosclerotic lesions.

Journal Article↗
PubMed1982

Mucinous gastric hyperplasia in a colony of rhesus monkeys (Macaca mulatta) induced by polychlorinated biphenyl (Aroclor 1254).

Since 1971, 45 of 259 male rhesus monkeys housed in a primate building have died of a chronic and progressive disease characterized by diarrhea, dehydration, weakness, gingivitis, emaciation, and alopecia. The principal necropsy finding in these monkeys, and in eight others killed for experimental purposes, was hypertrophic and hyperplastic mucinous gastropathy involving both the mucosa and submucosa. The toxic agent involved was identified as the polychlorinated biphenyl (PCB), Aroclor 1254. The suspected source of the toxic agent was a concrete sealer used during building construction.

Animals↗
PubMed1981

Complicating factors in evaluating coronary artery atherosclerosis.

The most commonly used morphological descriptors of coronary artery atherosclerosis are cross-sectional intimal area and "percent stenosis." Cross-sectional intimal area, i.e. plaque area, describes lesion size, without normalizing for differences in arterial size. "Percent stenosis" describes the percentage of the area within the internal elastic lamina that is occupied by plaque. When using intimal area and percent lumen stenosis data from atherosclerosis regression experiments there may be interpretational difficulties not only in determining the extent to which atherosclerosis has regressed, but also in whether or not regression has occurred. Specifically, if there if a minimal decrease in intimal area, i.e. little or no regression of atherosclerisis, and the artery becomes larger, percent lumen stenosis will decrease, in some cases substantially, indicating improvement or "regression" of the disease. In experiments where the age, body and heart weights of baseline animals are different from those of the regression animals, part of the improvement that is seen in "percent stenosis" may be attributable to animal growth and part to an actual decrease in intimal area. A particularly interesting, complicating factor is the apparent effect of atherosclerosis on arterial size. In an atherosclerosis progression experiment we compared coronary arteries from cynomolgus monkeys fed either a control diet or an atherogenic diet for 36 months. Ages, body weights and heart weights were similar between the groups. The animals fed the atherogenic diet had much larger coronary artery intimal areas, but also had considerably larger coronary arteriese as indicated both by area enclosed by the internal elastic lamina and lumen area. These findings suggest that in growing animals atherosclerosis may result in increased arterial size and thereby complicate interpretations of atherosclerosis progression and regression experiments.

Animals↗
PubMed1980

Influence of dietary fats and an oral contraceptive on plasma lipids, high density lipoproteins, gallstones, and atherosclerosis in african green monkeys.

Twenty-nine African green monkeys were fed diets for 22 months containing 0.79 mg cholesterol/kcal and 40% of calories as either safflower oil or butter with or without the addition of an estrogen- and progestin-containing oral contraceptive. Plasma cholesterol concentrations ranged from 199 to 250 mg/dl. Animals consuming the safflower oil diet had plasma cholesterol concentrations that averaged 61 mg/dl lower than those consuming butter. At least 72% of this lowering was due to a reduction in low density lipoproteins. Triglyceride concentrations were also slightly lower in animals consuming the safflower oil diet. The oral contraceptive lowered total plasma cholesterol concentrations in both diet groups by an average of 41 mg/dl with 54% of this lowering (22 mg/dl) due to a reduction in high density lipoprotein cholesterol. This effect occurred only during the 3 weeks while the contraceptive was being administered and was not apparent 1 week after stopping the drug. Animals consuming safflower oil had bile that was more lithogenic and had more gallstones than did those consuming butter. Addition of the oral contraceptive caused a slight increase in bile lithogenicity, but this increase was not statistically significant. There was no significant interaction between the oral contraceptive and either of the diets to exacerbate cholelithiasis. At the plasma cholesterol concentrations achieved only minimal amounts of atherosclerosis developed and there were no indications of differences due to diet or oral contraceptive in the extent of atherosclerosis.

Animals↗
PubMed1980

Time course of diet-exacerbated carotid artery atherogenesis in the White Carneau pigeon.

The carotid arteries of White Carneau pigeons fed an atherogenic diet developed fatty streaks, proliferative and atheromatous lesions. The carotid bifurcation had accelerated lesion development when compared to either the proximal internal carotid or the dorsal carotid artery. After 4 weeks of being fed an atherogenic diet, the bifurcation region of all birds showed some lesion involvement. Lesions at the bifurcation initially involved the medial and lateral walls; flow dividers became involved slightly later, with the anterior flow divider consistently developing thicker lesions than the posterior flow divider. Lesions progressed in terms of length of circumference, mean thickness, cross-sectional area, and percent lumen stenosis as the time fed the atherogenic diet increased.20

Animals↗
PubMed1980

A technique for localizing LDL by immunofluorescence in formalin-fixed and paraffin-embedded atherosclerotic lesions.

A protocol has been developed by which apo beta, the protein component of plasma low density lipoproteins (LDL), can be localized in four micron-thick sections of formalin-fixed and paraffin-embedded arteries with atherosclerotic involvement from man or non-human primate. An immunofluorescence procedure was employed that utilized affinity column-purified antibody coupled to fluorescein isothiocyanate (FITC). Although fixation reduced the intensity of fluorescence relative to that in cryostat sections, sufficient sensitivity was usually achieved when microscopy was performed using incident-light fluorescence together with a filter system adjusted for maximum absorption of FITC and by using oil immersion objectives. Furthermore, the use of various counterstains altered the color of the autofluorescence, normally strongly yellow, thus greatly enhancing the contrast and visualization of the apple green specific fluorescence. Non-chelated eriochrome black reduced tissue autofluorescence to barely visible levels, a feature useful in black and white photographs to demonstrate the localization pattern of LDL in arteries. This stain also reduced non-specific fluorescence. Other counterstains that proved useful were emthyl green, flazo orange and chelated eriochrome black. The latter two were particularly valuable for cellular detection. At low magnification LDL localization in atherosclerotic lesions from both human aortas and coronary arteries from monkeys fed an atherogenic diet, gave a pattern similar to those reported in cryostat sections of human lesions. At higher magnification, the improved detail of LDL localization could presumably be discerned as a result of immobilization of the soluble antigen by fixation, and by the ability to cut thinner sections of embedded material. This immunofluorescence procedure to localize LDL in formalin-fixed and paraffin-embedded atherosclerotic lesions should prove useful in both prospective as well as retrospective studies on clinical or chemical-pathological correlative studies on human tissues or in studies on atherogenesis using animal models.

Arteriosclerosis↗
PubMed1980

Myocardial infarction in a large colony of nonhuman primates with coronary artery atherosclerosis.

Relatively few cases of myocardial infarction associated with coronary artery atherosclerosis have been described previously in macaques. In this study the authors report the prevalence and characteristics of coronary artery atherosclerosis and myocardial infarction in 10 rhesus (Macaca mulatta) and two cynomolgus (Macaca fascicularis) macaques that were fed atherogenic diets for 16 months or longer. Our findings show clearly that myocardial infarction occurs in macaques with diet-induced atherosclerosis. The frequency seems to be related to the species, composition of the atherogenic diet, and length of time fed the atherogenic diet. The myocardial lesions are remarkably similar to those described in human beings in terms of location and gross and microscopic characteristics. The characteristics of coronary artery atherosclerosis, including the occurrence of thrombosis, severe stenosis, mineralization, atheronecrosis, and sterol clefts, especially in animals fed the atherogenic diets for longer periods of time, also closely resemble those of the arterial lesions found in human beings. The greatest prevalence of myocardial infarcts was found in rhesus monkeys fed a cholesterol-containing diet with 40% of calories supplied by peanut oil and in cynomolgus macaques from Malaya that were fed the same amount of cholesterol with 40% of calories from lard. Electrocardiographic abnormalities as well as the occurrence of unexpected and relatively sudden death in several of these nonhuman primates are also consistent with signs frequently observed in human beings.

Animals↗
PubMed1979

Fatal anaphylaxis in systemic mastocytosis.

A 42-year-old woman died after an episode of anaphylaxis associated with a raised serum histamine level. A diagnosis of systemic mastocytosis was established, with lymphadenopathy and hepatosplenomegaly, not associated with the usually pre-existing skin lesions of urticaria pigmentosa.

Adult↗
PubMed1979

Benign prostatic hyperplasia in a squirrel monkey (Saimiri sciureus).

Benign prostatic hyperplasia was diagnosed at necropsy in a middle-aged squirrel monkey (Saimiri sciureus). Grossly, the prostate gland was asymmetrically enlarged and had an irregular surface. Microscopically, both cystic glandular hyperplasia and fibromuscular, nodular hyperplasia were identified.

Animals↗
PubMed1978

Late failure in vein grafts: mediating factors in subendothelial fibromuscular hyperplasia.

Late failure of autologous vein grafts often results from excessive subendothelial fibromuscular hyperplasia. Varying factors have been implicated in this process, but the exact etiology remains unclear. In this study, three groups of animals were studied which had sections of common carotid artery replaced with autologous vein grafts. Group I had simple replacement, while Groups II and III had grafts supported by either tightly woven or loose mesh dacron prostheses. Thrombosis occurred only in the unsupported grafts. Unsupported grafts also had more subendothelial proliferation when compared to the loose mesh group. The combined thickness of the intima-media correlated inversely with the number of vasa present within the vein graft wall, i.e. significantly more vascularization was found in the mesh supported group when compared to the other groups. Grafts supported with the tightly woven prosthesis were relatively impervious to the ingrowth of vasa vasora. The data suggest that persistent distension of the graft wall by intra-arterial pressure influences the degree of subendothelial fibromuscular hyperplasia and may be interrelated to revascularization of the graft wall per se.

Animals↗