A multi-centre study of Osseotite implants supporting mandibular restorations: a 3-year report.

This multi-centre study evaluated the performance of the Osseotite implant in the mandibular arch. Osseotite implants (n = 688) were placed in 172 patients; 43.5% were placed in the anterior mandible and 66.5% in the posterior mandible. Fifteen per cent of the implants were placed in soft bone, 56.9% in normal bone and 28.1% in dense bone. During placement, 49.9% of the implants were identified as having a tight fit, 48.6% a firm fit and 1.5% a loose fit. About one-third of the implants (32.4%) were short (10 mm in length or less). After 36 months, only 5 implants had been lost, for a cumulative survival rate of 99.3%. The 3-year results of this study indicate a high degree of predictability with placement of Osseotite implants in the mandibular arch.

Ultrastructural responses of rat exocrine pancreas to cholecystokinin octapeptide and secretin.

The study examines the ultrastructural changes in the rat pancreas stimulated in vivo to secrete zymogen and fluid by the hormones cholecystokinin and secretin, administered either separately or in combination. The octapeptide of cholecystokinin (CCK-OP) (2.5 X 10(-7) g/kg) 5 min after injection produced discharge of electron-dense zymogen into the acinar lumen and intercellular canaliculi (ICC), leaving misshapen, collapsed zymogen granule profiles around the lumen. Five minutes after secretin (7.5 clinical units/kg), acinar cells were distended, rough endoplasmic reticulum was dilated, acinar lumina and ICC were expanded and filled by electron-lucent and flocculent contents, and there were "halo" zymogen granules and pale "vacuoles." Electron-lucent zones surrounding acinar and duct cell microvilli indicated transcellular fluid secretion. When secretin was administered with CCK-OP, the picture was a composite between zymogen and fluid secretory patterns. Zymogen granules took up fluid producing a halo appearance, pale vacuoles formed in acinar cells, and acinar lumina and discharging zymogen granules were of intermediate electron density. The results demonstrated that, although fluid is secreted by duct cells in response to secretin, a major site of secretin-stimulated fluid secretion is acinar cells. Fluid is transported across both cell types by transcellular routes, and the acinar cell fluid secretion is integrated with zymogen discharge. CCK-OP produces partial discharge of undiluted zymogen by exocytosis.

Ultrastructural responses by Golgi apparatus of rat submandibular gland to beta-adrenergic, alpha-adrenergic, and cholinergic stimulation.

Rat submandibular gland tissue pieces were stimulated in vitro for 30 min with a beta-adrenergic agent or a cyclic AMP analog to stimulate protein secretion, or with alpha-adrenergic or cholinergic agents or a Ca2+ ionophore to stimulate fluid secretion. Acinar cells were examined by transmission electron microscopy. In control tissue, acinar cells showed little evidence of secretory activity. The Golgi apparatus was sparse and was associated with a few small, immature secretory granules with fine fibrillar contents. Following secretory granule discharge stimulated by isoproterenol or dibutyryl cyclic AMP, acinar cells were constricted, and had extensive basolateral membrane folding and tightly packed rough endoplasmic reticulum. Golgi complexes were prominent and had multiple small granules with filamentous contents. After stimulation of fluid secretion by alpha-adrenergic agents (epinephrine, phenylephrine), or cholinergic agents (acetylcholine, carbachol, pilocarpine), or a Ca2+ ionophore (A23187), the Golgi apparatus had compact concave cisternae enclosing aggregates of tubulovesicles. Acinar cells were distended, basolateral membranes were expanded, and rough endoplasmic reticulum was dilated and vesiculated.

Colloid and crystal formation in parotid saliva of cystic fibrosis patients and non-cystic fibrosis subjects. I. Physicochemistry.

Two types of turbidity were found in parotid saliva from both cystic fibrosis (CF) patients and non-CF subjects. On cooling saliva, a rapidly forming, reversible, cold-dependent turbidity appeared in increasing amounts with decreasing temperature and increasing protein concentration. At 37 degrees, a slowly forming, stable turbidity appeared in increased amounts in parotid saliva samples containing increased amounts of calcium. The 2 degree centrifuged pellet consisted predominantly of protein, whereas the 37 degree pellet contained calcium, inorganic phosphate, and protein. The cold-dependent turbidity at 2 degrees was not inhibited by EDTA, but 37 degrees turbidity was dramatically inhibited. Urea and guanidine hydrochloride reduced 2 degree turbidity, and, to a lesser extent, inhibited 37 degree turbidity. The tendency towards higher levels of protein, amylase, and calcium in CF compared with child control parotid saliva (4, 6) causes a greater incidence and degree of turbidity formation in saliva of CF patients. In this paper only the nature of the turbidity has been investigated, not its relative occurrence in each group of subjects.

Colloid and crystal formation in parotid saliva of cystic fibrosis patients and non-cystic fibrosis subjects. II. Electron microscopy and electrophoresis.

Centrifuged pellets of turbid parotid saliva from cystic fibrosis (CF) patients and non-CF subjects, obtained from saliva kept at 2 degrees for 10 min, had the electron microscope appearance of amorphous, round particles, and were thought to be colloidal aggregates of organic material. Drops of turbid saliva, from samples incubated for 2 hr at 2 degrees or 37 degrees, additionally contained discrete, electron-dense crystals having well defined angular morphology: usually cubic, retangular, or approximately hexagonal. The inhibitors, urea, guanidine hydrochloride, and EDTA, resulted in no crystals being observed. Selected area electron diffraction from individual crystals showed predominantly hexagonal, rectangular patterns could be indexed as coming from hydroxyapitite. A transition from the hexagonal to the rectangular pattern and back to the hexagonal pattern could be obtained from individual crystals tilted in the electron microscope. The square diffraction pattern may be from octa-calcium or brushite. Polyacrylamide gel disc electrophoresis of the parotid saliva indicated that the sparingly soluble proteins in the 2 degree and 37 degree pellets comprised proline-rich proteins and a calcium-precipitable, trichloroacetic acid (TCA)-precipitable phosphoprotein, which fluoresced with amido schwarz and Coomassie brilliant blue G250.

Parotid gland function in children with cystic fibrosis and child control subjects.

Parotid saliva was collected from 22 children with cystic fibrosis (CF) and 21 control children. Stimulation was by 0.1 ml 5% citric acid on the tongue every 15 sec over a period of 10 min, and samples were collected for 2-min intervals. Stimulated saliva showed a lag period of low amylase release, and an activated period of higher amylase release. The major difference between CF and child control parotid saliva was in the elevated calcium concentrations in CF subjects. Flow rate and amylase, although higher in the CF group, were not raised to a statistically significant level. There were higher mean values for sodium and inorganic phosphate in CF children but statistical significance was minimal. Potassium values were almost identical in CF and control saliva. In the activated parotid saliva samples of both control and CF subjects there were positive correlations between flow rate and calcium, flow rate and sodium, anylase and calcium, and sodium and calcium, and negative correlations between sodium and potassium. The parotid function test has no value as a diagnostic test for cystic fibrosis, as even calcium values show too much overlap with control saliva to be of diagnostic worth.

Hypersecretion of zymogen granules in the pathogenesis of cystic fibrosis.

In the submandibular saliva of 10 cystic fibrosis subjects and 10 controls the turbidity and elevated calcium, protein, and amylase concentrations of the cystic fibrosis secretions, and precipitation of calcium and phosphate in a ratio consistent with hydroxyapatite have been confirmed. By electron microscopy the centrifuged deposits of the cystic fibrosis saliva were seen to be composed predominantly of round or oval subcellular corpuscles. By comparison with submandibular gland, these corpuscles have been identified as inclusion bodies (spherules) from within zymogen granules. Hydroxyapatite crystals formed on standing in the cystic fibrosis saliva. Polyacrylamide gel disc electrophoresis of the cystic fibrosis centrifuged deposits showed five bands, one of which, band 4, was more prominent in the deposit than in the supernatant gels. Comparisons have been made between these results and other studies and have shown (1) elevated calcium and protein in cystic fibrosis exocrine secretions; (2) simultaneous secretion of calcium and enzymes from salivary glands, stomach, and pancreas; and (3) increased salivary secretion of calcium and protein in response to parasympathomimetic and sympathomimetic drugs. Hypersecretion of calcium-containing zymogen granules is postulated as the cause of obstruction in cystic fibrosis.

Acute zinc toxicity in haemodialysis.

A country patient on home haemodialysis suffered acute nausea, vomiting, and fever during dialyses when she used water stored in a galvanized tank. She subsequently was found to have severe anaemia with raised plasma and erythrocyte zinc concentrations. Intercurrent hospital haemodialyses and subsequent home dialyses with deionized water were symptom-free.Experimental haemodialyses of dogs against small concentrations of zinc showed a disproportionate rise in plasma zinc and possible uptake of zinc by the liver.