Effects of a functional food supplemented with probiotics on biological factors related to dental caries in children: a pilot study.

PURPOSE: The aim of this study was to evaluate the effects of a functional food supplemented with probiotics on biological factors related to dental caries in children aged 3-5 years. METHODS: A repeated measures pilot study was conducted with children who have consumed a commercial milk containing two lactic acid bacteria as probiotics (WP milk) for a period of 3 months and another period of 3 months consuming a milk without probiotics (NP milk). Salivary pH, plaque index, pH variation before and after a sugar rinse, quantification of Streptococcus mutans in saliva and demineralisation of the carious lesions were determined at the beginning and at the end of both milk ingestion periods. RESULTS: Regarding WP milk, a non-significant decrease in terms of the concentration of S. mutans and pH variation (p > 0.05), a significant decrease (i.e. acidification) in salivary pH (p < 0.01) and a remineralisation of 39.4% of the caries were found. On the other hand, for NP milk, a non-significant increase in terms of the concentration of S. mutans, pH variation, salivary pH (p > 0.05) and a remineralisation of 64.2% were found. CONCLUSIONS: Lactic acid probiotics can contribute to the decrease in the number of cariogenic microorganisms. However, the appropriate selection of the bacteria type with regard to its acidogenicity is fundamental to avoid the generation of an effect contrary to that expected, e.g. a significant decrease in salivary pH.

A short history of Hodgkin's disease and Burkitt's lymphoma.

Although there are convincing descriptions of primary lymph node tumors dating from 1666, research into lymphoreticular disease began in 1832 when Thomas Hodgkin gave clinical descriptions and gross post mortem findings for seven cases. Later Reed and Sternberg concluded that Hodgkin's disease was indeed a different lesion with particular microscopical features. In the late 1950s, Burkitt described a tumor he observed in Uganda that affected the jaw. Originally it was called "round cell sarcoma." In 1961 Burkitt and O'Connor described the features of the clinical syndrome known today as Burkitt's lymphoma. Soon afterward, Wright established that this lymphoma was distinguished from other forms of lymphomas based on histopathologic features.

Annexin VI is attached to transverse-tubule membranes in isolated skeletal muscle triads.

Annexin VI is a 68-kDa protein of the Annexin family, a group of Ca2+-dependent phospholipid-binding proteins widely distributed in mammalian tissues including skeletal muscle. We investigated a) which membrane system contributes Annexin VI to skeletal muscle triads, and b) whether Annexin VI removal affects triad integrity or function. Annexin VI was present in isolated triads and transverse tubules but not in heavy sarcoplasmic reticulum vesicles, indicating that Annexin VI binds to either free or triad-attached transverse tubules. Extraction with EGTA of Annexin VI from triads did not alter their migration as a single band in sucrose density gradients or their ouabain binding-site density, indicating that triad integrity does not require Annexin VI. Caffeine-induced Ca2+ release kinetics and Ca2+ uptake rates were likewise not affected by Annexin VI removal from triads, suggesting that Annexin VI is not involved in these functions. Annexin VI purified from rabbit skeletal muscle displayed Ca2+-dependent binding to liposomes containing phosphatidylinositol 4,5-bisphosphate and phosphatidylcholine. Binding saturated at 1/20 molar ratio phosphatidylinositol 4,5-bisphosphate/phosphatidylcholine and was optimal at free [Ca2+] > or = 20 mM. Extraction of Annexin VI from triads did not affect the generation of phosphatidylinositol 4-phosphate, phosphatidylinositol 4,5-bisphosphate, or phosphatidic acid by endogenous lipid kinases, suggesting that despite its capacity to bind to negatively charged phospholipids, Annexin VI does not affect the kinase activities responsible for their generation.

Effect of the lipid environment on protein motion and enzymatic activity of sarcoplasmic reticulum calcium ATPase.

In order to investigate the roles of the physical states of phospholipid and protein in the enzymatic behavior of the Ca2+ -ATPase from sarcoplasmic reticulum, we have modified the lipid phase of the enzyme, observed the effects on the enzymatic activity at low temperatures, and correlated these effects with spectroscopic measurements of the rotational motions of both the lipid and protein components. Replacement of the native lipids with dipalmitoyl phosphatidylcholine inhibits ATPase activity and decreases both lipid fluidity, as monitored by EPR spectroscopy on a stearic acid spin label, and protein rotational mobility, as monitored by saturation transfer EPR spectroscopy on the covalently spin-labeled enzyme. Solubilization of the lipid-replaced enzyme with Triton X-100 reverses all three of these effects. Ten millimolar CaCl2 added either to the enzyme associated with the endogenous lipids or to the Triton X-100 soulbilized enzyme inhibits both ATPase activity and protein rotational mobility but has no detectable effect on the lipid mobility. These results are consistent with the proposal that both lipid fluidity and protein rotational mobility are essential for enzymatic activity.

Rotational dynamics of protein and boundary lipid in sarcoplasmic reticulum membrane.

We have used spin labels and electron paramagnetic resonance (EPR) to study the correlation between the rotational dynamics of protein and lipid in sarcoplasmic reticulum (SR) membranes. A short-chain maleimide spin label was used to monitor the submillisecond rotational mobility of the Ca-ATPase enzyme (using saturation transfer EPR); a free fatty acid spin label was used to monitor the submicrosecond rotational mobility of the bulk lipid hydrocarbon chains (using conventional EPR); and a fatty acid spin label derivative (long-chain maleimide) attached to the enzyme was used to monitor the mobility of hydrocarbon chains adjacent to the protein (i.e., boundary lipid). In the native SR membranes, the protein was highly mobile (effective correlation time 50 microseconds). The spectra of the hydrocarbon probes both contained at least two components. For the unattached probe, the major component indicated nearly as much mobility as in the absence of protein (effective rotational correlation time 3 ns), while a minor component, corresponding to 25-30% of the total signal, indicated strong immobilization (effective correlation time greater than or equal to 10 ns). For the attached hydrocarbon probe, the major component (approximately 70% of the total) was strongly immobilized, and the mobile component was less mobile than that of the unattached probe. When the lipid-to-protein ratio was reduced 55% by treatment with deoxycholate, protein mobility decreased considerably, suggesting protein aggregation. A concomitant increase was observed in the fraction of immobilized spin labels for both the free and attached hydrocarbon probes. The observed hydrocarbon immobilization probably arises in part from immobilization at the protein-lipid boundary, but protein-protein interactions that trap hydrocarbon chains may also contribute. When protein aggregation was induced by glutaraldehyde crosslinking, submillisecond protein mobility was eliminated, but there was no effect on either hydrocarbon probe. Thus protein aggregation does not necessarily cause hydrocarbon chain immobilization.