Search PubMed⌕ Search

Biomedical subjects

S H Song

Publications and source records attributed to S H Song.

At least 55 records · Page 3Linked to original sources
PubMed1990

A comparison of the size of fenestrations in the internal elastic lamina of young and old porcine aortas as seen with the scanning electron microscope.

The size of the fenestrations (windows) in the internal elastic lamina (IEL) of arteries may be important in the functioning of the blood vessel wall. The fenestrations are filled with collagen, muscle, and (or) ground substance, which must be removed to make the fenestration visible with the scanning electron microscope. All of the nonelastic components are removed with a hot alkali solution. Our experiments were designed to compare the fenestration size in the IEL of the thoracic aorta of young (6-8 weeks) and old (6-9 months) pigs. A protocol for digestion of young pig tissue was developed and showed that fresh young aortas should be digested in 0.1 M NaOH at 75 degrees C for 2 h and fixed tissue should be digested for 5 h. The average area of the fenestrations for young pig thoracic aortas digested for 2 h was 1.8 +/- 0.29 (SE) microns 2 and for the old pig aortas digested for 2 h was 1.7 +/- 0.11 (SE) microns 2. These values were not significantly different (p greater than 0.05), but the IEL from young pigs appeared rougher than the previously reported smooth IEL of the adult pigs.

Aging↗
PubMed1989

Percutaneous transcatheteral biliary biopsy (PTBB)--a report of two cases.

In two patients with obstructive jaundice, percutaneous transhepatic cholangiography (PTC) and percutaneous transhepatic biliary drainage (PTBD) were performed. During PTBD, the percutaneous transcatheteral biliary biopsy (PTBB) with the biopsy forceps of the gastrofiberscope was performed through the biliary stent catheter. Biopsy specimens were successfully obtained and histopathologic findings were satisfactory in both cases.

Aged↗
PubMed1988

Arterial elastin as seen with scanning electron microscopy: a review.

All large arteries contain elastin, collagen, and muscle which can be seen with light microscopy and transmission electron microscopy. Elastin forms an internal elastic lamina (IEL) in all arteries, but also forms multiple fenestrated sheets in the media of the aorta and other large arteries. The fenestrations in the media are larger than those in the IEL. The adventitial elastin is more fibrous and often contains tubular elastin surrounding vasa vasorum when prepared by removing all non-elastin by placing the aorta in 0.1 N NaOH at 70-75 degrees C for five hours. The fenestrations are larger near branches and in an experimentally created poststenotic dilatation. Atherosclerosis appears associated with both new elastin formation in early atherosclerosis and elastolysis in late disease.

Animals↗
PubMed1985

Scanning electron microscopic studies of the vasa vasorum of thoracic aortas.

Using hot alkaline solution, the elastic laminae were extracted from aortas and observed with scanning electron microscopy. Vascular structures were found in the elastin layers of the tunica media in descending thoracic aortas of sheep, dogs, and pigs, and these tube-like structures were filled with elastomer which was injected through the heart of the animal in vivo. Sub-intimal microvessels were also found to be filled with the elastomer and it is concluded that vasa vasorum can exist close to the internal elastic lamina in these animals.

Animals↗
PubMed1985

A morphological comparison of aortic elastin from five species as seen with the scanning electron microscope.

The elastic laminae were extracted from thoracic aortas of adult animals including sheep, dogs, rabbits, cats and rats by treating them in hot alkaline solution (0.1 N NaOH at 75 degrees C) and observed with a scanning electron microscope. The elastic laminae are comprised of sheet-like internal elastic lamina, fibrous and membraneous elastin in tunica media, interlamellar fibers and hollow spaces which we presume were formerly filled with smooth muscle cells in the tunica media. These structures are the same in all five species except that the number of layers and the total thickness of the wall differs.

Animals↗
PubMed1984

Comparison of fenestrations in internal elastic laminae of canine thoracic and abdominal aortas.

All non-elastin tissue was removed from canine aortas by placing them in 0.1 N NaOH at 75 degrees C for varying periods of time. The segments of aorta were weighed in a Mettler Chemical Balance at intervals. In 10 dogs the average weight of the thoracic aorta was 5.01 +/- 0.388 (SE) g while that of the abdominal aorta was 3.08 +/- 0.346 g. After digestion, the thoracic aorta weighed 3.34 +/- 0.0275 g and the abdominal aorta 0.85 +/- 0.085 g. Thus, the elastin makes up 67% of the thoracic aorta but only 28% of the abdominal aorta. These are equivalent to 0.334 g/kg body weight for the thoracic aorta and 0.224 g/kg body weight for the abdominal aorta. The values were always stable between 5 and 7 h and usually between 3 and 12 h. Aortic elastin was obtained from 5 dogs after 5-7 h of digestion and prepared for analysis by scanning electron microscopy. The dimensions of the fenestrations in the internal elastic laminae were quantified as described previously. The lower abdominal aorta had the largest holes (2.227 +/- 0.048 micron), and the upper thoracic aorta the smallest holes (0.954 +/- 0.032 micron). There was no significant difference in the size of the fenestrations along the thoracic aorta, but those in the lower abdominal aorta were larger than those in the upper abdominal aorta. The possible significance of the fenestrations in the genesis of aortic disease is discussed briefly.

Animals↗
PubMed1983

Mechanical anisotropy of purified elastin from the thoracic aorta of dog and sheep.

Mechanical anisotropy was found in elastin from the wall of the thoracic aorta by testing digested vessels from seven mature dogs and five pregnant ewes. The elastin was purified by removing the muscle and collagen with 0.1 N NaOH at 75 degrees C for 5 h. Strips oriented circumferentially and longitudinally with respect to the vessel axis were cycled at increasing loads until failure. Combining the results for four dogs and three sheep the ultimate tensile strength was 405 X 10(3) +/- 155 X 10(3) SD N/m2 circumferentially and 189 X 10(3) +/- 85 X 10(3) SD N/m2 longitudinally. The difference is significant at p less than 0.01. The ultimate strain was not significantly different, 1.19 +/- 0.29 SD circumferentially and 1.01 +/- 0.26 SD longitudinally. At 0.4 strain, the Young's modulus for four samples from four dogs was 404 X 10(3) +/- 64 X 10(3) SD N/m2 circumferentially; the modulus for five samples from five dogs was 245 X 10(3) +/- 60 X 10(3) SD N/m2 longitudinally. The difference is significant at p less than 0.05. At 0.7 strain, the Young's modulus for four dogs was 486 X 10(3) +/- 82 X 10(3) SD N/m2 circumferentially and 343 X 10(3) +/- 62 X 10(3) SD N/m2 longitudinally. The difference is significant at p less than 0.05. The reasons for the anisotropy in terms of the structure are not obvious from preliminary studies using the scanning electron microscope with stretched samples.

Animals↗
PubMed1983

Quantitative changes in the size of fenestrations of the elastic laminae of sheep thoracic aorta studied with SEM1.

The elastic laminae were extracted from thoracic aortas of 6 adult sheep by treating them in 0.1 N NaOH at 75 degrees C, and the surface of internal elastic lamina (IEL) was observed for windows by scanning electron microscopy. The fenestration analysis on IEL showed that mean diameters of the holes ranged from 0.46 microns (+/- 0.013 SEM) to 1.35 microns (+/- 1.019 SEM), which is smaller than those of human cerebral arteries (7.0 +/- 0.34 at the apex of the bifurcation and 2.1 +/- 0.13 SEM microns in the straight sections; [3]), and mean densities ranged from 6,513 to 31,544/mm2. Both size and density of windows are found to increase when the digestion time in the hot alkaline solution is increased form 1 to 3 h. It is concluded that the IEL of the sheep thoracic aorta has smaller windows than human cerebral arteries and because of the wall thickness the thoracic aorta requires longer digestion times than human cerebral arteries.

Animals↗
PubMed1980

Pancreatic pseudocyst simulating dilated biliary duct system on computed tomography.

A case of pseudocyst simulating the biliary ductal system is reported. Several CT findings indicate that the biliary system was not involved: (a) no dilatation of the more proximal intrahepatic biliary radicles; (b) the gallbladder was not distended; (c) lucency extending to the left at the level of the pancreas; (d) a position more medial and anterior than anatomic for the distal common bile duct.

Adult↗
PubMed1978

Studies on splenic megakaryocytes. I. Recovery of megakaryocytes from the splenic venous outflow.

Spleens from 14 healthy adult cats were isolated and perfused with cell-free Ringer's solution. Histological studies on the splenic megakaryocytes, as well as a search for splenic megakaryocytes in samples of the splenic venous outflow, were performed. The samples of the splenic venous outflow contained a lower cellular concentration when perfusion was prolonged, but the number of megakaryocytes appearing in the venous samples increased. At least five different forms of megakaryocytes were observed from smears of the venous outflow: (i) unipolar, (ii) multipolar, (iii) foamy, (iv) mobile and (v) nuclear types. These types were also found in splenic venous outflow of dogs, kittens and bled cats. It is suggested that not only platelets but also the larger megakaryocytes can pass out of the splenic circulation. This may imply that megakaryocytes can be culled, matured in the splenic red pulp, and ultimately released into peripheral blood.

Animals↗
PubMed1978

Is inert gas washout from the tissues limited by diffusion?

To determine the extent to which diffusion may limit the exchange of gases stored in the tissues, nine dogs were allowed to breathe an O2-N2-Ar mixture until saturation was achieved; the inspired gas was then changed to one containing neither N2 nor Ar, and the level of these two species in the arterial and in the mixed venous blood was monitored during the washout. A theoretical analysis shows that in a situation where peripheral gas transport is limited entirely by perfusion, the washout curves should be identical, provided concentrations are expressed as a fraction of the initial value. When the process is restricted by diffusion through the tissues, Ar is expected to lag because of its higher molecular weight. In all animals, the rate of elimination of the two tracers was the same, indicating that the time course of storage or release of inert gas from body stores is governed (mainly or entirely) by perfusion.

Animals↗
PubMed1977

Endocardial surface structures of the feline heart observed with a scanning electron microscope.

Internal surface structures of the auricular and ventricular chambers were studied with scanning electron microscopy. We observed vascular connections between the ventricular chamber and the coronary vessels, including cords and papillary muscles covering the lining of the endocardium. The endothelial cells covering the inner surface of the endocardium appeared to be functionally active with many microvilli similar to pinocytic microprojections of other endothelial cells. The pinocytic microprojections ranged between approximately 100 and 300 A in diameter. The epicardium contained mainly bundles of collagenous fibers.

Animals↗
PubMed1976

Release of red cells from the slowly-exchanging splenic pool after noradrenaline administration.

Isolated, denervated, cat spleens were perfused at constant flow with modified Ringer solution. Perfusion, pressure, outflow rate, and outflow red cell concentration were measured against time. After splenic perfusion by 500 ml solution the cell washout curve became a single exponential function, indicating that only cells from the most slowly exchanging red cell compartment remained (these are immature and abnormal cells which adhere to the fine structures of the red pulp). Splenic contraction was induced by injection of 5 mug noradrenaline into the inflow after perfusion by 600 and 1000 ml of fluid, respectively; outflow cell concentration rose 17-fold before returning to baseline value and 32% of red cells in the spleen were expelled. The time course of changes in cell concentration was similar in shape but delayed with respect to that of outflow rate. The transit time of the cells from the site of release to the splenic vein must have exceeded 40 s, which is consistent only with release from the red pulp. Furthermore, at the peak of the cell concentration curve the mean reticulocyte count was 37.8%. Thus immature and abnormal red cells, which comprise the slowly-exchanging compartment, are indeed released from the spleen during contraction.

Animals↗
PubMed1975

Kinetics of the red cell washout from coronary vessels of isolated feline hearts.

Twenty seven isolated feline hearts were perfused with cell-free oxygenated Ringer-Locke solutions. The concentration of red blood cells in samples of venous outflow collected from the coronary sinuses was determined by means of a Celloscope counter. Cellular concentrations decreased gradually as the perfusion time increased, and from 10(9) to 10(5) cells per millilitre after 300 ml perfusion. When the ventricular lumens were filled with residual blood (group I, 15 cats), several red cell peaks were superimposed on the smooth exponential decay curve of red cell washout. It is suggested that the peaks were caused by ejection of red cells from the ventricular lumens into communicating branches between the ventricular lumens and coronary capillaries. In cases of blood-emptied hearts (group II, 12 cats) these peaks did not occur, and mathematical analysis showed that summing three exponential functions could approximate the whole washout curve of red cells. This suggests that the coronary circulation may be described by three red cell compartments. The functional implication of this analysis for the microcirculation in the coronary vessels was discussed.

Animals↗