Chenodeoxycholic and ursodeoxycholic acids alter motility and fluid transit in the canine ileum

We examined the effects of chenodeoxycholic acid (CDCA) and ursodeoxycholic acid (UDCA) on fasting motility patterns and transit in ileocolonic loops of 5 dogs. Animals were prepared with isolated loops (40 cm ileum and 5 cm colon) which maintained neuromuscular continuity with the intact bowel through a bridge of tunica muscularis. Myoelectrical activity was recorded from multiple serosal, monopolar electrodes and muscle contractions recorded from serosal strain gauges; fluid transit was assessed by continuous perfusion (1.4 ml min-1) of solutions containing polyethylene glycol 4000 marker, with or without bile acids. Saline perfusion did not disturb the fasting cycle of motility and mean cycle length in unperfused (106 +/- 7 min) loop was the same as during perfusion of saline (108 +/- 9 min). Bile acids abolished interdigestive cycles in 11 of 12 experiments, fasting patterns returned 64-106 min after bile acid perfusion was stopped. The fasting pattern continued to cycle normally in the proximal small bowel during bile acid perfusion. CDCA (15 mM) stimulated the occurrence of propulsive contractions of long duration. Bile acids shortened transit time through the loops and altered the pattern of flow towards a more continuous, steady stream. These effects of bile acids on ileal motility, like those described previously in the colon, could play a role in bile acid diarrhea.

Effects of morphine and atropine on motility and transit in the human ileum

We examined motility of the ileocecal region, pressures at the ileocecal sphincter, and ileal flow after therapeutic doses of morphine and atropine. Using a factorial design in two cells of 8 (2(3] subjects, drugs were given during fasting and postcibally. Morphine (100 micrograms/kg body wt as a bolus intravenously) and atropine (7 micrograms/kg body wt as a bolus) stimulated migrating bursts of phasic activity (similar to phase III of the migrating motor complex). Morphine initially stimulated ileal flow, but atropine could not be shown to have this effect. Atropine reduced markedly the occurrence of sporadic pressure waves in the ileum, but morphine did not. Whereas atropine delayed mouth-to-ileum transit of polyethylene glycol, given in a mixed meal, morphine did not. Naloxone, in the dosage used (40 micrograms/kg body wt as a bolus, followed by 10 micrograms/kg body wt X h) had no independent effects on motility or flow, but did blunt the stimulatory effects of morphine and atropine on migrating motor complexes. We could not demonstrate an effect of any drug on the transit of lactulose from terminal ileum to cecum. Neither morphine nor atropine had impressive effects on tone at the ileocecal sphincter. These observations, while not specifying the mechanisms for constipation after opiates or anticholinergics, highlight the complexities of small bowel transit in humans and point out that the antidiarrheal effects of drugs are probably multifactorial.

[Detection of anterior interventricular involvement after primary posterior wall infarct]

Forty-five patients (average age 53.3 +/- 9.4 years) underwent exercise stress testing coupled with exercise myocardial scintigraphy and right heart catheterisation on exercise during the 3rd week after primary posterior wall infarction. Coronary angiography and ventriculography were carried out 24 to 48 hours later. Significant (greater than or equal to 75%) left anterior descending disease was present in 9 patients (Group I) and absent in 36 patients (Group II). Tolerance of maximal exercise stress testing was good in all patients. The results were uninterpretable in on third of the cases because the theoretical maximal heart rate was not attained. No significant difference was noted between groups I and II with respect to: mean age, percentage of theoretical maximal heart rate attained, mean pulmonary capillary pressures at rest and during exercise, basal and exercise cardiac index, end diastolic index and angiographic left ventricular ejection fraction. The sensitivity and specificity for the detection of LAD disease were 80% and 84% for the exercise stress testing (n = 30), 44% and 75% for exercise right heart catheterisation (n = 30), 60% and 92% for exercise myocardial scintigraphy (n = 30), 100% and 75% for combined exercise stress testing and myocardial scintigraphy (n = 30) and 78% and 64% for combined exercise stress testing and myocardial scintigraphy and exercise right heart catheterisation (n = 45). These results show that in patients capable of performing maximal exercise stress tests, the best method of early detection of significant LAD disease after primary posterior infarction was combined exercise stress testing and exercise myocardial scintigraphy. These investigations are useful for the selection of candidates for coronary angiography.

Angioedema of the head and neck

A group of 143 patients with angioedema was reviewed. Women in their third and fourth decades were most commonly affected. Head and neck involvement was found in 94% of cases and this was the only anatomical site in 24%. Twenty-one patients had swelling of the oropharynx while four presented with laryngeal edema. A diagnosis of hereditary angioedema (HAE) was confirmed in one case. Asthma, allergic rhinitis, and drug sensitivity were significantly associated, while smaller numbers of patients had underlying vasculitis or active ongoing infection. The pathophysiology and management of angioedema are discussed.

Motility of the terminal ileum and ileocecal sphincter in healthy humans

Factors controlling the transit of contents between the ileum and cecum should be important determinants of intestinal function; however, the dynamics of the ileocecal region remain largely unexplored in healthy humans. Accordingly, prolonged recordings of intraluminal pressure were obtained from the distal ileum, across the ileocecal sphincter, and from the proximal colon of healthy adults. In one set of studies, 16 subjects each contributed 6 h of basal, fasting recordings; in 2 of the 16, postprandial patterns were also recorded. In a second set, 6 fasting subjects were studied for a total of 120 h. Less than 10% of interdigestive cycles (migrating motor complexes) reached the ileocecal sphincter. The remainder faded out and merged into an active, apparently random pattern of pressure waves that became more intense closer to the sphincter. Discrete, short bursts of phasic pressures migrated rapidly for long distances in the distal ileum and a unique peristaltic wave also migrated rapidly, though infrequently, through the region. Tonic pressures were recorded across the ileocecal sphincter but were present only during the passage of phasic pressure waves; basal tone was minimal. We believe these are the first prolonged observations of motility from the ileocecal sphincter of healthy humans. These descriptions provide insights into and a basis for further studies of a largely unexplored area of the human bowel.

Synthesis of membrane and secretory glycoproteins by the acinar pancreatic cells as visualized by radioautography

Young rats were injected with 3H-fucose and killed at 10 min, 1, 4 and 24 h thereafter. Samples of the pancreas were processed for light- and electron-microscopic radioautography and then analyzed quantitatively. Fucose label was taken up in the supranuclear region of acinar pancreatic cells that were maximally labeled at 1 h after injection. Between 1 and 24 h after injection there was a very marked decrease in the concentration of label in the pancreatic acini. Radioautography at the ultrastructural level demonstrated that the earliest time interval the silver grains indicating the sites of newly synthesized glycoproteins were predominantly observed over the Golgi apparatus of the acinar cells. The quantitative analysis indicated that condensing vacuoles were labeled from 10 min to 4 h after injection. At 1 h the concentration of label in the Golgi apparatus was greatly diminished while it was significantly higher in the secretory (zymogen) granules. At this interval the secretion product visualized in the lumen of the acini and of the ducts was found to be labeled. At 4 h both the zymogen granules and the plasma membrane were significantly labeled. Further analysis carried out on the zymogen granules indicated that fucose-labeled glycoproteins were located in the granule membrane as well as in the granule content. In conclusion, 3H-fucose is added to glycoproteins in the Golgi apparatus of the acinar cells. Then, labeled glycoproteins are collected within condensing vacuoles and zymogen granules and released into the acinar lumen as secretion products. This latter event, which almost certainly is a consequence of exocytosis, may also account for the addition of granule-membrane glycoproteins to the plasma membrane.

Glycoprotein synthesis and migration in beta cells of the islets of Langerhans as shown by quantitative light- and electron-microscopic radioautography

L-3H-fucose was injected intravenously into rats that were killed from 10 min to 7 days after isotope administration. Semi-thin and thin sections of the islets of Langerhans were processed for light- and electron-microscopic radioautography, respectively, and analyzed quantitatively. L-3H-fucose was incorporated into newly synthesized glycoproteins in the Golgi apparatus of the beta cells and subsequently labeled glycoproteins migrated to secretory granules and plasma membrane. Therefore, some of the glycoproteins synthesized by the beta cells of the islets of Langerhans are destined for the renewal of plasma membrane. Although the labeling of the secretory granules was clearly demonstrated, it was not possible to decide if the newly formed glycoproteins are incorporated into the content or into the membrane of the granule. Thus, the fate as well as the function of secretory-granule glycoproteins could not be determined precisely. Several hypothesis concerning the presence of glycoproteins in the secretory granules in relation with insulin metabolism are considered.

Glycoprotein secretion in the hypothalamo-neurohypophyseal system of the rat

Although the secretory products of the hypothalamo-neurohypophyseal system are not glycoproteins, synthesis and migration of these macromolecules occur within its secretory neurons. After being labeled with 3H-fucose in the Golgi apparatus, newly synthesized glycoproteins migrate to secretion granules, lysosomes and the plasma membrane of the secretory neurons, as demonstrated by quantitative electron-microscopic radioautography. Secretion granules bearing newly synthesized glycoproteins migrate to the pars nervosa, the labeling pattern of which was studied in rats killed from 4 h to 14 days after the isotope injection. Most of the silver grains were observed to overly the secretory axons. Labeling of pituicytes was negligible and the number of silver grains over the perivascular spaces was about 10% of the total at certain postinjection intervals. In the secretory axons, most of the silver grains over the different portions of the secretory axons changed with time. At the longer intervals, the percentage of silver grains increased over the nerve swellings (including Herring bodies) and decreased concomitantly in the undilated portions of the axons and in the nerve endings. This labeling pattern conforms with observations of the secretion products. Water deprivation increased the release of neurosecretion as well as glycoproteins from the pars nervosa. However, glycoproteins inside the Herring bodies were not easily releasible. There was a parallel decrease in the amount of secretion granules and 3H-fucose-labeled glycoproteins indicating that the glycoproteins are predominantly a constituent of the granule content. Some newly synthesized glycoproteins were probably also used in the renewal of the axonal membrane. The labeling of smooth vesicles in nerve endings was discussed. In conclusion, most of the glycoproteins synthesized in the perikarion of the hypothalmic secretory neurons migrate inside secretion graules along the axon to the pars nervosa where they are secreted.

Incorporation of L-(3H)-fucose into glycoproteins of the adrenal gland of mice. Light microscope radioautographic study on semi-thin sections

To study the biosynthesis and intracellular migration of glycoproteins in the adrenal gland, adult mice were injected intravenously with L-(3H)-fucose and killed from 10 min to 14 days after injection. Semi-thin sections of the adrenal glands were then processed for radioautography. Incorporation of labeled fucose occurred in the steroid-secreting cells of the three zones of the cortex as well as in the adrenalin (A) and noradrenalin (NA) cells of the medulla. At short intervals after injection, the main site of incorporation was the paranuclear region of the cells, suggesting uptake by the Golgi apparatus. Subsequently, labeled glycoproteins migrated from the paranuclear region to other cell sites. The labeling pattern observed in the adrenocortical parenchyme strongly suggests that the glycoproteins are transferred to lysosomes, lipofuscin granules and the cell coat (glycocalyx). Counts of silver grains clearly indicate that these glycoproteins undergo renewal. The qualitative and quantitative analysis of the radioautographs also suggest that glycoproteins, acting as intracellular carriers of steroids, may be released to the extracellular environment together with the hormones. Most of the glycoproteins synthesized by the A and NA cells of the adrenal medulla seem to be transferred to secretion granules in which they may play some role in the cytophysiology of these structures. It is likely that glycoproteins are released from the cells during exocytosis of secretory granules.

Radioautographic and biochemical studies of secretion of venom protein in the South American rattlesnake Crotalus durissus terrificus

Protein secretion was investigated in the main venom gland of the South American rattlesnake, using radioautographic and biochemical techniques after a single intracardiac injection of L-(3,5-3H)tyrosine. All the snakes were injected at the fourth day of the secretory cycle and killed at 1/2, 1, 2, 4, 8 and 24 hours after injection. Most of the radioactive amino acid is cleared from the blood stream up to four hours after injection. On the other hand the specific activity (c.p.m./mg of protein) of the intracellular proteins reaches a peak at the 4-hour time interval decreasing afterwards. There was a good correlation between the values of the specific activity of the intracellular proteins and those of the silver grain density over the secretory cells at the several time intervals after the injection of 3H-tyrosine. The results of the quantitative analysis carried out in light- and electron-microscope radioautographs led to the conclusion that venom proteins are synthesized in the rough endoplasmic reticulum of the secretory cells, transferred to the Golgi apparatus from where they are carried to the secretory tobule lumen by the secretion granules. The fact that the values of the relative concentration of the radioactivity of he intracisternal granules double at the last three time intervals, strongly suggests that these structures are formed by the aggregation of the amorphous material present inside the cisternae of the rough endoplasmic reticulum.

Glycoprotein secretion in the mouse submandibular gland as revealed by radioautography after L-3H-fucose injection

Glycoprotein secretion in the mouse submandibular gland was investigated by light microscope radioautography of semi-thin sections after the administration of L-3H-fucose. The incorporation of the precursor in the acini was negligible. 3H-fucose was taken up in the paranuclear region of the cells lining the intercalated, secretory, striated and excretory ducts. This labeling pattern was interpredted as addition of the precursor to glycoproteins within the Golgi apparatus. Incoropration in the intercalated duct was restricted to the cells with fine cytoplasmic granules. The glycoproteins synthesized by the intercalated and secretory ducts were transported to the saliva by the secretion granules. It is assumed that the glycoproteins synthesized in the striated and excretory ducts are plasma membrane glycoproteins which seem to renew continuously. Quantitation of the radioautographs supplied data concerning the incorporation of 3H-fucose into newly synthesized glycoproteins as well as the renewal of the labeled macromolecules in each duct.

Radioautographic study of glycoprotein biosynthesis and renewal in the ovarian follicles of mice and the origin of the zona pellucida

L-fucose-3H was injected intravenously into mice which were killed at several time intervals after injection and semi-thin sections of their ovaries were processed for radioautography and analysed quantitatively; At the same time the specific activity of serum glycoproteins was determined. Glycoprotein biosynthesis was demonstrated in the oocytes, granulosa and stromal cells. The silver grain density of the follicular fluid in large follicles reached a peak at 4 h, remained high at 8 h after injection and decreased steadily at the subsequent intervals. It was demonstrated that the labeling pattern of the follicular fluid depends on the secretory activity of the granulosa cells and also on the specific activity of serum glycoproteins. The collapsed zonae pellucidae which represent the highest degree of follicular atresia are able to take up glycoprotein macromolecules. Based on this finding and also on the labeling pattern of the large follicles it was shown that there is very little synthesis of specific glycoproteins for the zona pellucida in large follicles. A more specific labeling of the zona pellucida occurred in the medium follicles. Following the growth of these follicles having a previously labeled zona pellucida, it was demonstrated that this extracellular structure is secreted by the oocyte.

Light microscope radioautographic study of glycoprotein secretion in the hypothalamic-neurohypophysial system of the rat, after L-fucose-3H injection

Fucose-3H was injected into the cerebral ventricle of rats that were killed at several time intervals after injection. Semi-thin sections of the supraoptic nucleus and neurohypophysis were processed for radioautography and analysed quantitatively. Silver grains indicating the site of fucoselabeled glycoproteins were first located at the perinuclear region of the secretory neurons. The highest silver-grain density in these cells was observed at 2 h after injection , declining afterwards. Silver grains over the neurohypophysis were observed from 2 h on, reached a peak at 1 day after injection and decreased in the subsequent time intervals. The distributions of the silver grains over the neurohypophysis fitted Poissonian distributions and these were shown to be heterogeneous at the several time intervals. Pituicytes were not labeled. The percentage of silver grains over the Herring bodies increased with time. In rats deprived of water after fucose-3H injection there was a great increase in the release of labeled glycoproteins from the neurohypophysis. These results indicate that the glycoproteins synthesized by the secretory neurons of the hypothalamic nuclei are secreted in the neurohypophysis.

Formation and turnover of plasma membrane glycoproteins in kidney tubules of young rats and adult mice, as shown by radioautography after an injection of 3H-fucose

The formation and turnover of the glycoproteins of the plasma membrane have been investigated by quantitative radioautography in the kidney tubules of young rats and adult mice killed at various time intervals after an intravenous injection of 3H-fucose. In young (40 g) rats killed five to ten minutes after the injection, radioautographs of distal tubule cells show that the Golgi apparatus contained about 85% of the cell label. By 30 hours, only 8% of the label remained in this organnele, whereas 67% was in the plasma membrane, indicating that most of the label had migrated from Golgi apparatus to this membrane. Similarly, in proximal tubule cells, about 82% of the label was initially in the Golgi apparatus, but less than 2% remained at 30 hours, at which time 78% was in the plasma membrane. In the latter cells, the apical tubules and vacuoles became heavily labeled before the apical microvilli did and, therefore, may be involved in the transit of label from the Golgi apparatus to the microvillous membrane. The results are interpreted to mean that, in kidney tubule cells, the Golgi apparatus is the site of a continuous incorporation of fucose into glycoproteins and that these migrate to the plasma membrane. In fully formed cells, such a conclusion would imply a continuous turnover of plasma membrane glycoproteins. However, in the rapidly growing kidney of young rats many new cells are added daily, the growth of which might involve net addition as well as turnover of glycoproteins. Accordingly, the experiment has been repeated in adult mice, in which the cells are assumed to be fully formed. Furthermore, since turnover implies eventual decrease of incorporated label, some of the animals have been killed at longer intervals, up to 27 days after injection. In these adult mice, as in young rats, prompt Golgi uptake and subsequent migration of label to the plasma membrane were observed in distal and proximal tubules cells. With time the label content of the plasma membrane decreased gradually, and by 27 days had virtually disappeared. From grain counts, it is concluded that the mean half-life of glycoproteins in the apical membrane of distal tubule cells is about two days, whereas in both the apical and basal membranes of proximal tubule cells, it is slightly over three days.

Characterization of ribonucleic acids from the venom glands of Crotalus durissus terrifucus (Ophidia, Reptilia) after manual extraction of the venom. Studies on template activity and base composition

RNA synthesis in the venom glands of Crotalus durissus terrificus was stimulated by the manual extraction of the venom (milking). RNA was extracted from venom glands activated by milking and fractionated by centrifugation through sucrose density gradients. Template activity for protein synthesis and base composition of the RNA fractions were studied. RNA fractions that sediment between 18S and 4S had the highest template activity. The base composition analysis indicated that the 28S and 18S rRNA have a C+G content of 65.4 and 58% respectively. The ;melting' temperature (T(m)) of DNA in 0.15m-NaCl-0.015m-trisodium citrate, pH7.0, was 85 degrees C, corresponding to a C+G content of 38%. The base ratio of the RNA fractions that showed a high template activity was intermediate between that of rRNA and homologous DNA. The possible role of these fractions in the synthesis of the two main toxins (crotoxin and crotamine) of the South American rattlesnake's venom is discussed.

Migration of glycoprotein from the Golgi apparatus to the surface of various cell types as shown by radioautography after labelled fucose injection into rats

A single intravenous injection of L-[(3)H]fucose, a specific glycoprotein precursor, was given to young 35-45 g rats which were sacrificed at times varying between 2 min and 30 h later. Radioautography of over 50 cell types, including renewing and nonrenewing cells, was carried out for light and electron microscope study. At early time intervals (2-10 min after injection), light microscope radioautography showed a reaction over nearly all cells investigated in the form of a discrete clump of silver grains over the Golgi region. This reaction varied in intensity and duration from cell type to cell type. Electron microscope radioautographs of duodenal villus columnar cells and kidney proximal and distal tubule cells at early time intervals revealed that the silver grains were restricted to Golgi saccules. These observations are interpreted to mean that glycoproteins undergoing synthesis incorporate fucose in the saccules of the Golgi apparatus. Since fucose occurs as a terminal residue in the carbohydrate side chains of glycoproteins, the Golgi saccules would be the site of completion of synthesis of these side chains. At later time intervals, light and electron microscope radioautography demonstrated a decrease in the reaction intensity of the Golgi region, while reactions appeared over other parts of the cells: lysosomes, secretory material, and plasma membrane. The intensity of the reactions observed over the plasma membrane varied considerably in various cell types; furthermore the reactions were restricted to the apical surface in some types, but extended to the whole surface in others. Since the plasma membrane is covered by a "cell coat" composed of the carbohydrate-rich portions of membrane glycoproteins, it is concluded that newly formed glycoproteins, after acquiring fucose in the Golgi apparatus, migrate to the cell surface to contribute to the cell coat. This contribution implies turnover of cell coat glycoproteins, at least in nonrenewing cell types, such as those of kidney tubules. In the young cells of renewing populations, e.g. those of gastro-intestinal epithelia, the new glycoproteins seem to contribute to the growth as well as the turnover of the cell coat. The differences in reactivity among different cell types and cell surfaces imply considerable differences in the turnover rates of the cell coats.

In vivo incorporation of 3 H-galactose by thyroid follicular cells of the rat, as shown by electron microscopic radioautography

Radioactive galactose was injected intravenously into rats and localized in thyroid follicular cells by electron microscopic radioautography at intervals ranging from 2.5 to 30 min after injection. The galactose label was mostly present in the Golgi apparatus at 2.5 min, with some of it in the adjacent rough endoplasmic reticulum. By 30 min, the label was found in apical vesicles and colloid. It was concluded that galactose is added to the carbohydrate side chains of incomplete thyroglobulin molecules during their travel through the cisternae of the endoplasmic reticulum into the Golgi apparatus; the uptake begins as this organelle is approached, but predominates within it. The thyroglobulin molecule which has thus been labeled is transported by the apical vesicles to the colloid.

Radioautographic study of in vivo and in vitro incorporation of fucose-3H into thyroglobulin by rat thyroid follicular cells

The incorporation of fucose-(3)H in rat thyroid follicles was studied by radioautography in the light and electron microscopes to determine the site of fucose incorporation into the carbohydrate side chains of thyroglobulin, and to follow the migration of thyroglobulin once it had been labeled with fucose-(3)H. Radioautographs were examined quantitatively in vivo at several times after injection of fucose-(3)H into rats, and in vitro following pulse-labeling of thyroid lobes in medium containing fucose-(3)H. At 3-5 min following fucose-(3)H administration in vivo, 85% of the silver grains were localized over the Golgi apparatus of thyroid follicular cells. By 20 min, silver grains appeared over apical vesicles, and by 1 hr over the colloid. At 4 hr, nearly all of the silver grains had migrated out of the cells into the colloid. Analysis of the changes in concentration of label with time showed that radioactivity over the Golgi apparatus increased for about 20 min and then decreased, while that over apical vesicles increased to reach a maximum at 35 min. Later, the concentration of label over the apical vesicles decreased, while that over the colloid increased. Similar results were obtained in vitro. It is concluded that fucose, which is located at the end of some of the carbohydrate side chains, is incorporated into thyroglobulin within the Golgi apparatus of thyroid follicular cells, thereby indicating that some of these side chains are completed there. Furthermore, the kinetic analysis demonstrates that apical vesicles are the secretion granules which transport thyroglobulin from the Golgi apparatus to the apex of the cell and release it into the colloid.