STUDIES OF NATIVE GLYCOGEN ISOLATED FROM SYNCHRONIZED TETRAHYMENA PYRIFORMIS (HSM)

Native glycogen was isolated from Tetrahymena pyriformis (HSM) by isopycnic centrifugation in cesium chloride density gradients. A density of 1.62 to 1.65 was isopycnic for glycogen. Most of the banded glycogen existed as 35 to 40 mµ particles which had a sedimentation coefficient of 214. These particles were composed of aggregates of 2 to 3 mµ spherical particles. Extraction of glycogen with hot alkali reduced the sedimentation coefficient of native glycogen from 214 to 64.7 and the particle diameter from approximately 40 to 20 mµ and smaller. Cell division was synchronized by a repetitive 12-hour temperature cycle, and glycogen was measured at several times during the cell cycle. The temperature cycle consisted of 9.5 hours at 12°C and 2.5 hours at 27°C. Approximately 90 per cent of the cells divided during the last 1.5 hours of the warm period. The carbohydrate/protein ratio of cells at the end of the cold period was 0.27 and was reduced slightly during the warm period. Glucose was incorporated into glycogen during both periods, although the rate of incorporation was greater during the warm period. No preferential incorporation on the basis of particle size was noted. Incorporation was measured in both native glycogen and KOH-extracted glycogen. Tetrahymena glycogen is compared with rat liver glycogen previously isolated by similar procedures, and the significance of using combined rate-zonal and isopycnic centrifugation for isolating native glycogen is discussed.     

Sterilization of Regenerated Collagen Sutures with β-Propiolactone

Data are presented to show that β-propiolactone when properly applied is a very effective agent for sterilization of regenerated collagen sutures. The chemical sterilization is accomplished with little or none of the loss in strength encountered with heat sterilization. The finished sterile suture is obtained without any harmful residue that might be detrimental to the patient.     

ELECTRON MICROSCOPY OF THE OXYNTIC CELL IN THE GASTRIC GLANDS OF THE BULLFROG (RANA CATESBIANA) : I. The Non-Acid-Secreting Gastric Mucosa

The fine structure of the oxyntic cell from the gastric glands of the bullfrog was studied in lead hydroxide—stained sections of gastric mucosa fixed in buffered osmium tetroxide and embedded in n-butyl methacrylate. The oxyntic cell in non-acid-secreting stomachs (gastric juice pH, 7.4–7.8) is characterized by: (a) numerous closely packed smooth surfaced vesicular and tubular profiles disposed randomly in the cell; some of these elements show interconnections making it possible to identify this component with smooth surfaced endoplasmic reticula of certain other cell types, (b) a small percentage of rough surfaced profiles characteristic of endoplasmic reticula possessing RNP particles on the outer membrane surfaces, (c) a Golgi complex consisting of multiple isolated non-polarized arrays of smooth surfaced parallel elongated profiles and associated vesicular elements, (d) a sparse granular component (140 A) scattered freely in the cytoplasmic matrix, (e) numerous mitochondria with a dense matrix and containing an unusually large number of closely approximated cristae, (f) a number of zymogen granules consisting of either a dense body limited by a membrane or surrounded by a halo of less dense material which is in turn limited by a membrane, and (g) a number of granules (~260 A) containing several smaller granules (~80 A) identified presumably as glycogen. Intracellular canaliculi were not observed. Instead the free surface of the oxyntic cell facing the lumen of the gastric gland shows a complicated plication of the plasma membrane. Intercellular canaliculi are seen frequently between adjacent oxyntic cells. The walls of these canaliculi are made up of folded and ruffled cell membranes. The basal surface of the cell also exhibited this type of configuration. Occasional smooth surfaced profiles are seen communicating with the free surface, the wall of an intercellular canaliculus, or the basal surface of the cell. Although nerve endings were not found in association with oxyntic cells, unmyelinated nerves were observed in the vicinity of the gastric glands.     

Autoradiographies de Coupes d'os compact après marquage aux isotopes in vitro

Résumé Etude qualitative et quantitative du marquage in vitro de coupes d'os compact. Détermination du rôle joué par les processus de diffusion, d'adsorption et d'échange dans ces phénomènes.

---

Zusammenfassung Qualitative und quantitative Studie der in vitro-Markierung von Schliffen aus Knochen-Compacta. Bestimmung der Rolle der Diffusions-, Adsorptions- und Austauschprozesse für diese Vorgänge.

---

---

Avec 2 Figures dans le Texte

---

La partie expérimentale de ce travail a pu être réalisée grâce à des subsides fournis par l'European Office of the Air Research and Development Command [contrat n^o AF 61 (514) 1175], par l'Institut Interuniversitaire Belge des Sciences Nucléaires, et par la Commission pour la Science Atomique du Fonds National Suisse de la Recherche Scientifique.     

Cerebrovascular Occlusive Disease—Experience with Panarteriography in 300 Consecutive Cases

Three hundred patients with cerebrovascular occlusive disease have had cerebral angiographic examination at the Veterans Administration Hospital, San Francisco, in the last five years. The present technique consists of preliminary visualization of the aortic arch and the major extracranial branches, followed by selective study of the subclavian and carotid arteries as necessary for evaluation of the intracranial circulation.Nine major complications occurred (an over-all incidence of 3 per cent). Two patients died after angiography and seven had major neurologic deficits persisting for more than 24 hours. Three of these patients had permanent damage, but four recovered completely.One-third of the patients had extracranial disease and one-third had intracranial disease. No significant lesion was found in the remainder. In the 212 patients with lesions, multiple lesions were common, the average number being three. Six patients had brain tumors and five had aneurysms.The mechanism of the stroke could be ascertained readily in most of the patients, but the extent of the disease and the resulting symptoms varied considerably. Several patients with occlusion of most of the cerebral vessels had minimal symptoms, while others had catastrophic symptoms but only minimal findings at arteriography.     

Quantification of concentration changes in neonatal human cerebral oxidized cytochrome oxidase.

The oxygenation of cerebral cytochrome oxidase in vivo was investigated in eight newborn preterm infants. Near-infrared spectroscopy was used to quantify changes in the concentration of oxidized cytochrome oxidase ([CytO2]) observed during alterations in arterial oxygen saturation (SaO2) in the range of 85-99% and of carbon dioxide tension (PaCO2) in the range of 4.3-9.6 kPa. No relation was found between changes in SaO2 and [CytO2]. Alterations in PaCO2 were positively related both to changes in [CytO2] and total cerebral hemoglobin concentration [( Hb]t). The changes in [CytO2] ranged from 0.09 to 0.33 (median 0.21) mumol.l-1.kPa-1. The ratio [CytO2]/[Hb]t ranged from 0.06 to 0.12 (median 0.08). The relation of delta [CytO2] to the change in cerebral blood volume (delta CBV) was calculated: delta [CytO2]/delta CBV ranged from 0.09 to 0.18 (median 0.11) mumol/ml. These results define a fraction of cerebral cytochrome oxidase in the newborn infant that is oxidized after an increase in PaCO2 but demonstrate that a change in SaO2 in the range studied was not sufficient by itself to change [CytO2]. They differ from results of studies in adults; this may reflect significant differences between adult and neonatal brain.     

Abdominal distension alters regional pleural pressures and chest wall mechanics in pigs in vivo

Abdominal distension (AD) occurs in pregnancy and is also commonly seen in patients with ascites from various causes. Because the abdomen forms part of the "chest wall," the purpose of this study was to clarify the effects of AD on ventilatory mechanics. Airway pressure, four (vertical) regional pleural pressures, and abdominal pressure were measured in five anesthetized, paralyzed, and ventilated upright pigs. The effects of AD on the lung and chest wall were studied by inflating a liquid-filled balloon placed in the abdominal cavity. Respiratory system, chest wall, and lung pressure-volume (PV) relationships were measured on deflation from total lung capacity to residual volume, as well as in the tidal breathing range, before and 15 min after abdominal pressure was raised. Increasing abdominal pressure from 3 to 15 cmH2O decreased total lung capacity and functional residual capacity by approximately 40% and shifted the respiratory system and chest wall PV curves downward and to the right. Much smaller downward shifts in lung deflation curves were seen, with no change in the transdiaphragmatic PV relationship. All regional pleural pressures increased (became less negative) and, in the dependent region, approached 0 cmH2O at functional residual capacity. Tidal compliances of the respiratory system, chest wall, and lung were decreased 43, 42, and 48%, respectively. AD markedly alters respiratory system mechanics primarily by "stiffening" the diaphragm/abdomen part of the chest wall and secondarily by restricting lung expansion, thus shifting the lung PV curve as seen after chest strapping. The less negative pleural pressures in the dependent lung regions suggest that nonuniformities of ventilation could also be accentuated and gas exchange impaired by AD.     

Image analysis of rat satellite cell proliferation in vitro

Myogenic cells were isolated from adult rat skeletal muscles and cultured in vitro. Cell proliferation was analyzed between days 1 and 14. The cell cycle phases were determined by examining Feulgen-stained cultures with a cell image processor. The nuclei were automatically analyzed by calculating 18 parameters relating to the texture and densitometry of chromatin and the shape of each nucleus. Cell cycle phases were characterized (Moustafa and Brugal, 1984). The recognition methods made it possible to analyse the nuclei of the myogenic cell populations which were either involved in each phase of the mitotic cycle, or left out of the cycle after fusion into myotubes.After 3 hr of culture 10% of the cell population was involved in the cell cycle. In the presence of foetal calf serum, this percentage increased until day 3 after plating. At that time, the DNA content of 28.2% of the cell population was higher than 3C, whereas it is 2C in G1 or G0 nuclei; image analysis showed that 42% of these cells were in S or G2 phase. From day 4, the proliferation rate gradually slowed down until day 8. After day 8, when numerous myotubes differentiated, the percentage of S and G2 phase cells had diminished to between 3 and 8%. The percentage of nuclei in G0 increased when the first myotubes differentiated around day 5. Myotube nuclei were largely in G0. When horse serum was added to the culture medium on day 4 to enhance myotube differentiation, significant cell proliferation was observed before cell fusion.These methods of analysis give the first daily pattern of myogenic cell proliferation and fusion in a cell population isolated from adult muscles.