In vitro studies on the influence of cements on the alkaline effect of calcium hydroxide

abstract – The influence of different base materials on the alkaline effect of calcium hydroxide as well as the alkaline effect of calcium hydroxide-containing materials (Dycal® and Hydra®) was measured in an in citro system meant to imitate a cavity with a pulp exposure. The base materials did not appear to have any appreciable influence on the alkaline effect of calcium hydroxide as tested in this study. Like pure calcium hydroxide, Dycal and Hydrex seemed to have a lasting alkaline effect, i. e. the same effect before and after hardening of the materials. The alkaline effect of these materials, however, was lower than that of pure calcium hydroxide.     

Iron Metabolism and “Sports Anemia”

Abstract Several reports have suggested that iron deficiency might explain “sports anemia” especially in long distance runners. The present study was made to further study the iron metabolism in runners as the proposed cause of “sports anemia” is abstruse considering the good iron nutrition in these athletes. Based on a screening of 43 elite male runners, using bone marrow hemosiderin, serum ferritin and transferrin saturation, two groups of subjects were selected for a very extensive study on iron metabolism. In group 1 (n=5) iron depletion was suggested in at least one of the screening studies. In group 2 (n=7) at least one test strongly indicated good iron repletion. This experimental design was chosen to obtain two groups with similar body composition and exercise load but different iron metabolism. The studies comprised determinations of red cell and plasma volumes, plasma iron turnover and red cell incorporation of radioiron, red cell indices, plasma iron and transferrin, red cell protoporphyrin, serum ferritin, serum haptoglobin, urinary iron losses, iron absorption, bone marrow hemosiderin, dietary intake of energy and nutrients and a Desferal test. Pooling the results together it was obvious that none of the subjects were truly iron-deficient. A few occasional findings suggesting low iron stores cannot be satisfactorily explained and indicate that further studies are needed     

Growth hormone 24-h serum profiles during pregnancy—lack of pulsatility for the secretion of the placental variant

Summary. Serum profiles of growth hormone (GW) were recorded for 24 h in women at different stages of normal pregnancy. Two monoclonal antibodies directcd against different epitopes and unaffected by human placental lactogen were used in radioimmunoassays to distinguish the pituitary 22K-GH from the placental GH variant. The 'normal' episodic peak activity of GH in non-pregnant and first trimester pregnant women was dramatically changed into a continuous very stable secretion during late pregnancy. This change was first observed at 17 weeks gestation. It is concluded that during the second half of pregnancy, serum measurements of GH reflect a major contribution from a non-cpisodically secreted placental GH variant and a concomitant suppression of pituitary GH. This specific signal, i.e. a continuous GH secretion, may be an important regulator of maternal liver metabolism during pregnancy.     

In vivo and in vitro studies of inhibitory effects of restorative dental materials on salivary esterases

The influence of 18 dental materials on the activity of esterases isolated, from human whole saliva has been studied. Eugenol on its own was a strong competitive inhibitor of the esterases II-2a (Ki = 3.3/10^?5 M) and II-2b (Ki = 4.7/10^?6 M). Except for Luralite® all the materials that contained eugenol as one of the components (IRM®, Nobetec® and Opotow®) were noncompetitive inhibitors. Additional in vitro inhibitors were: Adaptic®, Aspa®, Coe-pack® and the amalgam ANA 68®. Treatment with Nobetec packs in vivo resulted in a decrease in the esterase activity of whole saliva.     

Tooth avulsion in children: to replant or not

Replanting avulsed teeth with a doubtful long‐term prognosis due to unfavorable extra‐alveolar conditions has recently been questioned by Kenny and Barrett ( 1 ). Many factors, however, still favor replanting such teeth. First of all, reliability of failure predictors has not yet been tested in prospective studies. Secondly, preservation of even resorbing replanted teeth may offer significant long‐term advantages in preparation for definitive treatment. Also, for psychological reasons, replantation can significantly reduce the anxiety and despair of both the injured child and the parents. Furthermore, decoronation of a resorbing anterior tooth will allow it to serve as a matrix for alveolar bone formation and preserve an otherwise resorbing alveolar process, thereby leaving an environment of bone and soft tissue that is optimal for both single implant insertion or fixed prosthesis. Finally, replantation and subsequent decoronation, if indicated, appears to be cost‐effective in comparison with non‐replantation combined with subsequent repeated prosthetic tooth replacements owing to vertical alveolar growth of adjacent ridge areas, with eventual definitive implant placement or a fixed prosthesis.     

Toxic activity of the CdtB component of Haemophilus ducreyi cytolethal distending toxin expressed from an adenovirus 5 vector

Wising C, Magnusson M, Ahlman K, Lindholm L, Lagergård T. Toxic activity of the CdtB component of Haemophilus ducreyi cytolethal distending toxin expressed from an adenovirus 5 vector. APMIS 2010; 118: 143–9. The Haemophilus ducreyi cytolethal distending toxin (HdCDT) catalytic subunit CdtB has DNase‐like activity and mediates DNA damage after its delivery into target cells. We constructed a replication‐deficient adenovirus type 5 (Ad5) vector expressing CdtB and investigated the toxic properties of this vector on HeLa cells. Ad5CdtB caused loss of cell viability, morphologic changes, and cell cycle arrest, findings similar to HdCDT intoxication. This confirmed that CdtB is responsible for the toxicity of the holotoxin when expressed in cells following transduction by an adenoviral vector, and indicated a possible potential of this novel strategy in studies of activity of intracellular products and in gene therapy of cancer.     

Tissue concentration and release of substance P-like immunoreactivity in the dental pulp

The concentration of substance P-like immunoreactivity (SPLI) was determined in dental pulps from cat, dog and man by radioimmunoassay. Pulps from mature cats showed the highest SPLI-levels (mean 32 pmol/g); these are comparable to or higher than those found in any other organ outside the central nervous system. The SPLI concentrations were lower in pulp from immature teeth. The immunological and chromatographic behav behaviour of the pulpal SPLI from cat and man resembled that of synthetic substance P (SP), indicating that the assayed substance is closely related to or identical with SP. Release of pulpal SPLI in canine teeth ws evoked by stimulation of the inferior alveolar nerve in anaesthetized cats. In 9 of 16 experiments the amounts of SPLI found in pulp suprafusates following stimulation (4–31 fmol) were larger than those in unstimulated controls (0–7 fmol). Stimulation also reduced the pulpat tissue concentration of SPLI to 60% of that in homologous control pulps. The high concentration of SPLI found in the dental pulp and the demonstration of nerve-induced release strengthen the hypothesis that SP serves some function in the dental pulp.     

Platelet deposition in rabbit common carotid arteries promoted by arterial stenosis and spasm

Coronary arteriograhy in patients with ischemic heart disease often shows spasm of the coronary arteries. The question is whether spasm is a triggering factor for thrombosis in a stenotic artery. If so, what are the mechanisms for this? A stenosing teflon ring was applied to the right common carotid artery of anesthetized rabbits and l‐nor‐epinephrine was dripped over the outer surface of both carotid arteries, causing spasm. In control animals an indifferent solution did not cause spasm. Nineteen rabbits were killed 30 min or 24 h after treatment. Microscopically, arteries with stenosis and spasm contained thrombi nearby the stenosis significantly more often than arteries in control animals. In another 14 rabbits, killed at 30 min, the number of platelets on the intimal surface away from the stenosis was quantified. In arteries with both stenosis and spasm the counts were significantly greater than in arteries with no treatment. The intimal surface in stenotic and spastic arteries showed assumed imprints of eddying flow and endothelial injury downstream and upstream of the stenosis. Spastic arteries showed increased folding of the internal elastic membrane, altered endothelial cells, and adhering platelets. Spasm in a rabbit artery with a preformed stenosis facilitates thrombosis probably by creating increased flow disturbances. Spasm may induce endothelial injury, causing adherence of platelets.