Accurate presurgical determination for implant placement by using computerized tomography scan

A template is often used for the presurgical planning of implant placement. However, a major drawback is that the CT image of the radiopaque marker is not often clear. This article describes a method of fabricating a template with a stainless steel tube sprue for accurate radiographic evaluation and implant placement. Stainless steel tube sprues are inexpensive, indicate the eventual implant inclination, and facilitate precise placement, from the CT scan without any interference from scattered radiation.     

Stimulation of neutrophil adherence to vascular endothelial cells by histamine and thrombin and its inhibition by PAF antagonists and dexamethasone.

1. The behavioural effects of a selective cholecystokininB (CCKB) receptor antagonist CI-988 were investigated in rodents. 2. In three rodent tests of anxiety (rat elevated X-maze, rat social interaction test and mouse light/dark box) CI-988 over the dose range 0.001-10.0 mg kg-1, (i.p.) produced an anxiolytic-like action. The magnitude of this effect was similar to that of chlordiazepoxide (CDP). In contrast, the selective CCKA receptor antagonist, devazepide, was inactive. CI-988 also showed anxiolytic-like action in the rat conflict test but the magnitude of this effect was about 2.5 fold less than that of CDP. 3. Central but not peripheral administration of the selective CCKB receptor agonist, pentagastrin, like FG 7142, produced an anxiogenic-like action. 4. The pentagastrin-induced anxiety was dose-dependently antagonized by CI-988, whereas devazepide was inactive. However, ten times higher doses of CI-988 were required to block a similar action of FG 7142. 5. In contrast to CDP, CI-988 up to 3000 fold higher doses than those inducing anxiolysis was inactive in tests measuring sedation and ataxia. It also failed to antagonize pentylenetetrazol-induced tonic seizures. Furthermore, CI-988 did not interact with alcohol or barbiturates. Thus, CI-988 appears to be an anxioselective compound. 6. The anxiolytic-like action of CDP in the rat elevated X-maze was dose-dependently antagonized by flumazenil. In contrast, the benzodiazepine receptor antagonist failed to block a similar effect of CI-988. 7. Thus, CI-988 shows anxiolytic-like activity in several animal models of anxiety.(ABSTRACT TRUNCATED AT 250 WORDS)     

Bronchodilating effect of intravenous magnesium sulfate in bronchial asthma

The bronchodilating effect of magnesium sulfate (MgSO4) was studied in ten asthmatic patients with mild attacks. In five patients, 0.5 mmol/min of MgSO4 was administered intravenously for 20 minutes, and the time courses of respiratory resistance, forced vital capacity, and forced expiratory volume at 1 s were studied. In another five patients, MgSO4 dose-response curves were obtained. Soon after administration began, MgSO4 relieved bronchoconstriction in a dose-dependent manner. Maximum responses (mean +/- SE) of respiratory resistance, forced vital capacity, and forced expiratory volume were 71% +/- 3%, 117% +/- 5%, and 118% +/- 1% of initial values, respectively, and were similar to the effects of additional albuterol inhalation. The infusion of MgSO4 also improved dyspnea and piping rales in three other asthmatic patients with a severe attack. We conclude that intravenous infusion of MgSO4 produces a rapid and marked bronchodilation in both mild and severe asthma and may be a unique bronchodilating agent.     

The inhibitory effect of isoproterenol and dibutyryl cyclic-AMP on the immediate skin reaction

The concomitant injection of isoproterenol with house dust allergen inhibited the immediate skin allergic reaction in asthmatic patients. Pretreatment with dibutyryl cyclic AMP showed an inhibitory effect on the whealing formation to the allergen. Those results showed the inhibitory effect of isoproterenol on the skin reaction through increasing intracellular cyclic AMP levels.     

Differences between the bony interfaces of titanium and hydroxyapatite-alumina plasma-sprayed titanium blade implants

Histopathologic study was done to reveal the difference of bony interface in the mandibular bone between titanium blade implants and titanium implants coated with the mixture of hydroxyapatite-alumina by the plasma-spray technique, using the improved undecalcified histologic technique and the image analyzing system. In 4 adult shepherd dogs, the implantation was performed in the molar region of the mandible 2 months after tooth extraction. The coated implants and the non-coated ones were inserted respectively in the mandibles. They were sacrificed on the 5th, 7th, 14th and 28th day postoperatively. In 5-day implant after insertion, granulation tissues or fibrous connective tissues were observed around both implants in bone tissues. In 7-day implant, osteoid tissues regenerated around the apex of both implants, but attached a little to them. In 14-day implant, osteoid tissues or woven bone regenerated around both implants and attached more to the coated implant (approximately 13.7%) than the non-coated one (approximately 6.0%). In 28-day implant, regenerative woven or lamellar bone attached much more to the coated implant (approximately 63.4%) than the non-coated one (approximately 8.8%). Bony interface increased remarkably in the coated implants, chronologically. The results showed that the plasma-sprayed hydroxyapatite-alumina coating was effective for the initial fixation of endosseous dental implants.     

Bisindole alkaloids from myxomycetes Arcyria denudata and Arcyria obvelata

A new bisindole sulfate (1) and arcyroxocin B (2) were isolated from wild fruiting bodies of Arcyria denudate, along with three known bisindoles (4-6). Dihydroarcyriacyanin A (3) was obtained from wild fruiting bodies of Arcyria obvelata, along with a known bisindole (7). The structures of these compounds were elucidated on the basis of spectroscopic data, and this is the first report of full characterizations of arcyroxocin B (2) and dihydroarcyriacyanin A (3). Compounds 2, 3, and 6 showed cytotoxicity against Jurkat cells.     

Biomimetic configurational arrays of hydroxyapatite nanocrystals on bio-organics

Biomimetic configurational arrays of hydroxyapatite (HAp) nanocrystals on several bio-organics, collagen (Col), chondroitin sulfate (ChS), and their mixture, were comparatively studied. The nanocomposites of HAp/Col, HAp/ChS, and HAp/Col/ChS were synthesized through a precipitation method with calcium hydroxide suspension and phosphoric acid solution containing Col, ChS, and their mixture, respectively. The (0 0 2) diffraction of the synthesized HAp crystals on a Col fiber showed an around 60 arching angle, while that on a ChS fiber showed just around 10 degrees. The same configurational arrays of HAp crystals could also be obtained on the mixture of Col and ChS fibers. The different electron diffraction patterns of the HAp crystals on the Col and ChS fibers were explained by the different macromolecular configurations of the Col and ChS fibrils which compose their fibers. The results may be applicable to develop a bone substitute which mimics the peculiar configurational arrays of HAp crystals found in bone and their detailed organic composition.