Collagen and prostaglandin synthesis in force-stressed periodontal ligament in vitro.

A periodontal organ culture system capable of receiving orthodontic type forces was developed. Histological, radioautographical, collagen, and prostaglandin synthetic data demonstrated the vitality of the organ over a 24-hour period of culture. Significant increases in the proportion of type III collagen synthesized during periods of active stress were found, but no alterations in relative levels of prostaglandins synthesized during periods of force application were discernible.

Differential effects of dietary vitamin E and antioxidants on eicosanoid synthesis in young rabbits.

This study was designed to evaluate the effects of dietary vitamin E and synthetic antioxidants on prostacyclin (PGI2) synthesis in isolated aorta segments and perfused hearts as well as thromboxane (TxA2) synthesis in thrombin-stimulated washed platelets. Weanling male New Zealand rabbits were fed a vitamin E-deficient basal diet or the basal diet supplemented with either all-rac-alpha-tocopherol acetate or propyl gallate or DPPD (N,N'-diphenyl-p-phenylenediamine). After 30 days on the diet, plasma tocopherol level, pyruvate kinase and liver microsomal NADPH oxidase were determined. DPPD but not propyl gallate prevented the development of myopathy. None of the synthetic antioxidants could substitute for vitamin E in decreasing enzymatic lipid peroxidation. PGI2 release by the aorta was lowered in vitamin E deficiency and was highest with DPPD supplementation. In the Langendorff perfused heart, however, PGI2 release was highest in the vitamin E-deficient group, possibly due to cardiomyopathy. TxA2 synthesis by washed platelets challenged with thrombin was independent of the antioxidant status of the animal. The data showed that dietary antioxidants selectively affect eicosanoid synthesis in different tissues.

Effect of dietary vitamin E on sulfolipid synthesis in rat submandibular salivary gland.

The effect of feeding diets containing various levels of vitamin E for 6 months on the in vitro synthesis of sulfolipids in rat submandibular salivary glands (SMG) was elucidated. The incorporation of [35S]sulfate into sulfolipid of SMG from rats on deficient or "normal" vitamin E diets was quite similar, however, the uptake was significantly increased in glands from rats on diets high in vitamin E. Whereas, in many instances, antioxidants can mimic the effect of vitamin E, in the present study, the antioxidant N,N'-diphenyl-p-phenylene diamine (DPPD) was actually found significantly to depress sulfolipid-labeling below that noted in SMG from all other diets. The results suggest that in the synthesis of SMG sulfolipid the action of vitamin E may be more than that of a simple antioxidant.

Activation of rutin by human oral bacterial isolates to the carcinogen-mutagen quercetin.

Oral streptococci, isolated from the mouths of 2 healthy subjects, hydrolysed innocuous rutin, a flavonoid glycoside, to its genotoxic aglycon quercetin, in vitro. The isolates were identified as Streptococcus milleri. The glycosidase, rutinase, was studied in cell-free extracts derived from one of the isolates, grown anaerobically in batch cultures by the use of a bioassay, the Ames test, in which S-9 was replaced by the cell-free extracts. This streptococcal rutinase was: constitutive, partly inducible, cytosolic, most active for rutin and most active at pH 6.5. Type-culture collection strains of other oral streptococci (Streptococcus salivarius ATCC 25975 and Streptococcus mutans strain 6715-10) showed no capacity for rutin degradation. A hypothesis for a novel role of the oral microflora in a disease process other than caries and periodontal disease, namely intra-oral cancer, is presented. The possibility of a bacterial liberation of the genotoxic quercetin in situ could be but one example of its involvement in the local carcinogenic process.

Biphasic modulation of platelet phospholipase A2 activity and platelet aggregation by mepacrine (quinacrine).

The modulation of rat platelet phospholipase A2 (phosphatide 2-acylhydrolase, EC 3.1.1.4) and rat platelet aggregation by mepacrine was investigated. The 2-acyl specificity of phospholipase A2 activity was confirmed by using 1-[14C]palmitoyl-2-[3H]arachidonylphosphatidylcholine as substrate. Under optimal pH, phospholipase A2 activity was not affected by aspirin but was inhibited by indomethacin. Contrary to previous reports, a biphasic modulatory role of mepacrine on phospholipase A2 activity and platelet aggregation was demonstrated. The data suggest that platelet aggregation is mediated via phospholipase A2.

Role of cyclic GMP in submandibular gland secretion.

Cholinergic stimulation of rat submandibular gland slices resulted in a rapid increase in the level of cyclic GMP. This increase was dependent upon the presence of Ca2+ and a phosphodiesterase inhibitor. Adrenergic agonists did not produce a significant elevation of cyclic GMP. The addition of Ca2+ to slices preincubated with the divalent ionophore A23187 caused a rapid rise in cyclic GMP levels which were unaffected by cholinergic stimulation. While these results could support a function for cyclic GMP in cholinergic-mediated K+-release from these glands, they do not support a role for this nucleotide in alpha-adrenergic agonist-induced K+-release or protease secretion.

Sulpholipid formation in rat submandibular gland.

The sulphotransferase activity of rat submandibular gland differs markedly from that of testis, kidney and brain. The addition of lipid acceptors and Mn2+ (or Mg2+), which have been shown to enhance sulpholipid formation from adenosine 3'-phosphate 5'-sulphatophosphate in other tissues, has either no effect or inhibits the transfer process.

Potassium release from submandibular salivary gland in vitro.

Rat submandibular gland slices, incubated in continuously-gassed Krebs-Ringer bicarbonate buffer, were shown to release K+ in response to alpha-adrenergic and muscarinic cholinergic stimulation. The system employed the specific alpha-, beta-adrenergic and cholinergic receptor-blocking agents phentolamine, propranolol and atropine, respectively, in combination with the agonists L-epinephrine and carbamylcholine both of which required the presence of Ca2+ for their effect. The introduction of Ca2+ into the cell via the ionophore A23187, with all neurotransmitter receptors blocked, resulted in K+ release. Ouabain also allowed extensive K+ release which was in addition to, and hence independent of, that elicited by epinephrine and carbamylcholine. Ethacrynic acid, a potent inhibitor of salivary secretion in vivo, had no influence on K+ movement. K+ was released by both physalaemin and an eledoisin-related peptide independently of normal neurotransmitter receptors. The activity of the eledoisin-related peptide did not require the presence of extracellular Ca2+. The implication of cyclic GMP at some stage of K+ release was suggested by experiments with a phosphodiesterase inhibitor. The results support an hypothesis where the initial stimulus at either alpha-adrenergic or muscarinic cholinergic receptors causes an immediate permeability change such that Ca2+ enters the cells resulting in K+ release. The loss of K+ is quickly countered by the ouabain-sensitive (Na+ + K+) ATPase which would be activated by the lowered intracellular K+ levels.

Incorporation of (1-14C)palmitoyl-CoA into phosphatidylcholine by plasma membranes of rat submaxillary glands in vitro.

1. On incubation with the isolated rat submaxillary gland plasma membranes, [1-14C]palmitoyl-CoA was incorporated mainly into phosphatidylcholine and hydrolysed to [1-14C]palmitic acid and CoASH. 2. The addition of lysophosphatidylcholine enhanced the incorporation into phosphatidylcholine and lowered the hydrolysis of palmitoyl-CoA markedly. 3. In the presence of lysophosphatidylcholine, palmitoyl-CoA incorporation into phosphatidylcholine was maximum at 0.1 mM palmitoyl-CoA, 0.5 mM lysophosphatidylcholine and between pH 7.0 and 9.0. 4. The incorporation into phosphatidylcholine was stimulated by Na+, K+ and K-, inhibited by Ca2+ and Mg2+ and unaffected by sodium deoxycholate and ATP. 5. Epinephrine inhibited the incorporation of palmitoyl-CoA into phosphatidylcholine in the presence or absence of ATP, the inhibition being more in the presence of ATP than in its absence. Dibutyryl adenosine 3':5'-monophosphate mimicked the inhibitory effect of epinephrine.

Testosterone in human saliva.

Testosterone has been detected in whole human saliva. Levels averaged (+/- SE) 295 +/- 36 and 195 +/- 25 pg/ml in adult males and females, respectively, and usually were undetectable in children. In adult males, the excretion of testosterone in saliva appeared to follow a circadian rhythm.