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Biomedical subjects

B G Anderson

Publications and source records attributed to B G Anderson.

33 records · Page 2Linked to original sources
PubMed1980

Microvasculature of the canine heart demonstrated by scanning electron microscopy.

In previous studies, a marked diminution in left coronary flow during systole has been demonstrated. This phenomenon has been said to result from capillary compressin by the contraction of myocardium and perhaps also from active changes in the state of the smooth muscle in the wall of the coronary vessels. In order to determine the morphological factors involved in this occurrence, and to gain a three-dimensional concept of the myocardial microvasculature, casts were prepared by perfusion of the coronary arteries with methyl methacrylate. Because of the conditions of the perfusion, these casts were considered to demonstrate a state of muscular contraction. Following maceration, portions of the casts were prepared for scanning electron microscopy (SEM). Arterioles of larger diameter were characterized by the helical configuration of the vascular replicas. Smaller vessels were categorized according to their directional pattern and their diameter. The arterioles gave rise to numerous large-diameter capillaries and also to short vessels that were guarded by sphincters. True capillaries, in some cases guarded by precapillary sphincters, were packed in densely stacked parallel sheets with numerous short anastomotic connections between them. Postcapillary venules were found to enter at regular intervals into larger venules arranged perpendicular to the capillary sheets. Most of these characteristics were found to be consistent throughout the microvasculature. These structural features were considered to be factors in the active regulation of blood flow through the myocardial microvasculature.

Animals↗
PubMed1979

Hydrofluoric acid burns. A report of a case and review of the literature.

Burns caused by exposure to hydrofluoric acid are occurring with ever-increasing frequency due to the wide use of this acid in industry and research. Such burns are characterized by severe progressive tissue destruction and excruciating pain resulting from the unique properties of the freely dissociable fluoride ion. The subungual tissues are especially susceptible to the destructive effects of hydrofluoric acid. The proper treatment of hydrofluoric acid burns requires prompt recognition and the institution of specific therapeutic measures by the attending physician.

Adolescent↗
PubMed1978

Scanning electron microscopy of microcorrosion casts; intracranial and abdominal microvasculature in domestic animals.

The use of methyl methacrylate corrosion casts prepared for portions of the vascular system has made it possible to examine numerous and extensive areas of microscopic structures on a 3-dimensional scale with the scanning electron microscope. By this means we have examined the arterial microvasculature of intracranial vessels among three domestic animal species. In addition, these vessels have been compared with the terminal branches of abdominal arteries in the dog. The results of this study suggest that the sphincteric control mechanisms of the vessels in the two regions may be structurally different from one another. In the case of the intracranial vessels, the terminal portion of the arteriole is continued by a precapillary arteriole composed of a chain-like series of muscular constrictions. This is most suitably described as a precapillary sphincter area, which terminates at the capillary. In the abdominal vessels, the precapillary arteriole is generally followed by a single precapillary sphincter at the origin of the capillary. These morphological characteristics may account, in part, for the difference in response of vessels in these two regions in hypovolemic shock.

Animals↗
PubMed1978

Shunting in intracranial microvasculature demonstrated by SEM of corrosion-casts.

The use of methyl methacrylate corrosion-casts has made it possible to examine the intracranial microvasculature on a three-dimensional scale with the scanning electron microscope. By this means we have compared regions of four cerebral and cerebellar arteries among three domestic animal species. The results of this study suggest that there are from one to three different levels of interarteriolar anastomosis between branches of the same or adjacent vessels. In the horse and ox anastomoses were demonstrated (1) at the level of the precapillary arterioles, (2) along the arterioles, and (3) between small pial arteries. In the dog only the first-named anastomoses were evident in this study. These morphological characteristics may explain in part, the shunting mechanism by which hypoxia may be reduced among intracranial capillary networks.

Animals↗
PubMed1977

Vasculature of the equine and canine iris.

Methyl methacrylic casts were prepared and tissue was freshly collected for histologic examination to compare the vascular supply and the structure of the vessels of the iris in the adult horse with those of the dog. In the horse, ciliary blood vessels divided in the iris and formed a complete major arterial circle of the iris. In the dog, the ciliary blood vessels divided in the ciliary body and, by means of recurrent branches, formed a complete arterial circle. From this circle, radial arteries extended toward the pupillary margin. The radial vessels in the horse were nearly straight and joined to form a prominent minor arterial circle of the iris at the level of the sphincter pupillae muscle. Radial blood vessels in the horse did not appear to be controlled by the sphincter muscles. Venous blood of the iris of the horse was carried to the ophthalmic vessels via 4 prominent vortex veins. Drainage from the iris of the dog was by way of 4 to 6 circular collecting veins in the ciliary region. From this site, blood passed either via the ciliary veins or via small vortex veins to the dorsal and ventral external ophthalmic and then to the ophthalmic plexus.

Animals↗
PubMed1976

Renal vasculature of the trout demonstrated by scanning electron microscopy, compared with canine glomerular vessels.

In order to gain additional information regarding renal circulatory patterns, we have used both ink and resin injections to study the arterial supply to the mesonephric kidney of trout. Arterial injections through the dorsal aorta with ink were made for histological preparations in which the length, termination and relationship of glomerular vessels were examined. Similar injections with methyl methacrylate were made in preparation of corrosion casts to provide us with gross replicas of the aortic branches to the kidney as well as casts of glomerular structure for scanning electron microscopy. The sequence of vessels through which arterial blood passed to the renal corpuscle and ultimately to the uriniferous tubules was traced. Each afferent arteriole was found to terminate in three to six branches which formed anastomosing circuits of capillaries; these vessels reunited at the hilum to form a single efferent arteriole. The efferent arterioles in trun traveled a short distance to peritubular capillary beds and sinusoids. Morphological evidence was found for preglomerular sphincter-like action only. The glomerular vessels were found to be similar to, although less complex than, those of the outer and mid-cortical regions of the dog kidney.

Animals↗
PubMed1975

Renal morphology of freshwater trout.

The nephron of the euryhaline freshwater salmonids is composed of the renal corpuscle and the renal tubules. Throughout much of the renal corpuscle, only the lamina densa separates the fenestrated processes of the endothelial cells from the foot processes of the visceral epithelium. The renal tubule consists of five distinct segments. The neck segment is short and intermittently ciliated; it lacks the mucous cells which appear in the neck segment of some teleosts. The proximal segment bears a dense bruch border and is both structurally and functionally divisible into a first and a second segment. The first portion is typified by the presence of short apical tubules, variously sized apical vacuoles, and numerous lysosomes. The second proximal segment is distinguished by the abundance and distribution of mitochondria throughout the cytoplasm. Infoldings of the basilar plasmalemma are especially prominent in this region. A cilated intermidate segment intervenes briefly between the proximal and distal portions of the tubule. The distal segment consists of cuboidal cells which bear scattered, short microvilli, small vesicles and multivesicular bodies. Renal tissue from several species of trout was examined in order to establish the basis for a common pattern of histological and ultrastructural characteristics within the family Salmonidae. In all species examined, renal structure was very similar and could readily be compared with that previously described in other freshwater and marine species.

Animals↗
PubMed1975

Effect of large doses of 131I-19-iodocholesterol on metapyralone-induced adrenal cortical hyperplasia in dogs.

The potential use of 131I-19-iodocholesterol to treat ACTH excess Cushing's disease was evaluated in the dog. Three normal female dogs were given LD50 radiation doses of 131I-19-iodocholesterol without producing gross or histopathologically demonstrable change of the adrenals at autopsy 3 months later. The adrenal cortices of three dogs were made hyperplastic (to simulate the adrenal cortex in Cushing's disease) with ACTH and three with Metapyralone. In addition these six dogs were given KD50 doses of 131I-19-iodocholesterol. Three months after treatment, the adrenal glands of the ACTH-treated dogs were not enlarged, the cortex was thicker than normal, and there were no changes attributable to irradiation. At 3 months, the Metapyralone-treated dogs had enlarged adrenals, widening of the adrenal cortex, and no necrosis or other changes attributable to irradiation. It is concluded that a therapeutic trial of 131I-19-iodocholesterol in the treatment of Cushing's disease is not indicated.

Adrenal Cortex↗