Examination of denture-cleaning methods based on the quantity of microorganisms adhering to a denture

doi: 10.1111/j.1741‐2358.2011.00461.x Examination of denture‐cleaning methods based on the quantity of microorganisms adhering to a denture Objectives: To investigate effective denture‐cleaning methods, we examined the relationships between the quantity of microorganisms adhering to dentures and the use of a denture brush and the frequency of use of a denture cleanser. Subjects and Methods: Denture plaque was collected from the mucosal surface of the examined dentures, which were 142 and 80 upper and lower complete dentures, respectively, worn by 96 outpatients (mean age: 71.9 years) of a university hospital and 41 nursing home residents (mean age: 84.8 years). The collected microorganisms were counted in terms of isolated representative colonies that were cultured and identified using standard methods. The use of a denture brush, the frequency of use, and the type and soaking time of denture cleansers as denture‐cleaning methods were surveyed. Results: The quantity of microorganisms was significantly lower in dentures of denture brush users than in those of non‐users in the outpatients (p < 0.01, Mann–Whitney U test). The quantity of microorganisms was significantly lower in the dentures of outpatients who used a denture cleanser daily or 3–4 times a week than in those who used one once or less per month and in the dentures of nursing home residents who used one daily than in those who used one at other frequencies (p < 0.05, Kruskal–Wallis test, followed by Dunn’s Multiple Comparison test). Conclusion: Within the limitations of this study, it was concluded that the use of a denture brush and daily use of denture cleanser should be recommended to complete dentures wearers as denture‐cleaning methods that effectively reduce the quantity of microorganisms adhering to dentures.     

Stereospecific interaction of a novel spirosuccinimide type aldose reductase inhibitor, AS-3201, with aldose reductase.

Aldose reductase (AR) is an NADPH-dependent enzyme implicated in diabetic complications. AS-3201 [(R)-(-)-2-(4-bromo-2-fluorobenzyl)-1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine-4-spiro-3'-pyrrolidine-1,2',3,5'-tetrone] is a structurally novel and potent ARI with an inhibitor constant (K(i) = 10(-)(10) M) 2000-fold lower than that of its optical antipode (S-isomer). To elucidate the inhibition modes and the stereochemical differences in their inhibitory potencies, we examined the interaction of these R- and S-isomers with AR under physiological conditions. Enzyme kinetic analysis, which was performed by using physiological substrates at 37 degrees C, showed that both isomers selectively act on the E-NADP(+) complex in both the forward and reverse reactions of AR. However, fluorometric titration analysis demonstrated that the affinities of the isomers for the E-NADP(+) complex are about the same as those for the E-NADPH complex and the apoenzyme. These results suggested that the selective binding to the E-NADP(+) complex arises from the predominance of this enzyme form during steady-state turnover rather than from binding specificity. Both the competition with a known active site-directed ARI and the protective effect on AR inactivation by N-bromosuccinimide showed that the isomers bind to the active site of the enzyme, but the thermodynamic parameters for the binding to AR indicated that additional hydrogen bonds and/or van der Waals interactions contribute to the energetic stabilization in the E-R-isomer complex. Molecular modeling, together with the deductions from spectroscopic studies, suggested that the succinimide ring and the 4-bromo-2-fluorobenzyl group of the R-isomer are optimally located for formation of a hydrogen-bonding network with AR, and that the latter benzyl group is also effective for the differentiation between AR and aldehyde reductase (a closely related enzyme).     

Modification of acyl-plasmin-streptokinase complex with polyethylene glycol. Reduction of sensitivity to neutralizing antibody

Acyl-plasmin-streptokinase complex has advantages as a 'site' directed fibrinolytic agent with the active site protected from the plasma protease inhibitors. But, in clinical use, the fibrinolytic potential of this acyl-enzyme complex is modified or abolished by the presence of streptokinase antibodies in the patients. Therefore, better therapeutic agents are required. In this work, chemical modification of the acyl-plasmin-streptokinase complex with polyethylene glycol was found to result in marked resistance to neutralization with streptokinase antibodies.     

Opiate receptor binding characteristics of dimeric analogues of mu-selective DAGO-enkephalin

DAGO-enkephalin ([ D-Ala2, MePhe4, Gly-ol5]enkephalin), a highly selective ligand for mu opiate receptors, was dimerized with a series of alpha,omega-alkanedioic acids (n = 2-12) at the OH-terminus. In the radioligand receptor binding assays with rat brain, most of the DAGO-enkephalin dimers with cross-linking methylene chain n (DEDn) were more potent than DAGO monomer. For delta receptors, affinity of DEDn was maximized with n = 8, which might be related to an optimal distance between two binding sites. For mu receptors, an increase in chain length resulted in a progressive loss of potency. Although all of DEDn are considerably mu-selective, with a mu/delta ratio of 15-50, DEDn exhibited fairly flat binding curves with 15-50% smaller sloped than that of DAGO, suggesting that the dimers interact more strongly with one of the possible two mu binding sites.     

Sealing of the follicular lumen of the anterior pituitary gland of the male rat

It is commonly accepted that follicular lumina of the adult rat anterior pituitary gland are tightly sealed by junctional complexes, especially tight junctions. In this report, we describe the presence of follicular lumina that are unsealed. Peroxidase (HRP) was used to study such structures and when injected through the femoral vein, was observed in association with a few follicular lumina, on their microvilli and around the cilia of folliculo-stellate cells. The existence of peroxidase-positive follicles clearly shows that follicles of the hypophysis are not always firmly sealed by tight junctions. The folliculo-stellate cells which faced the peroxidase-positive follicles displayed HRP deposits which were membrane bound within their cytoplasm. These findings suggest an absorptive function for the folliculo-stellate cells.     

Interaction of S-activated enkephalin analogs with opiate receptors

Enkephalin analogs containing a thiol activated by a thiomethyl (SCH3)*** or 3-nitro-2-pyridinesulfenyl (Npys) group were synthesized. Incubation of such S-activated enkephalin analogs as [D-Ala2, Leu(CH2S)SCH(3)5]enkephalin or [D-Ala2,Leu(CH2S)Npys5]enkephalin with guinea pig ileum (GPI) resulted in the continuous stimulation of the mu opiate receptors. This sustained GPI-activity was completely reversed with the antagonist naloxone, while subsequent washings elicited again the full enkephalin activity. When GPI showing full enkephalin activity was incubated with 1 mM dithiothreitol, about 70% of the activity was eliminated. Examination of enkephalin analogs containing Cys(Npys) at position 1, 5, or 6 suggested that no other thiols occur near the enkephalin binding site of the mu receptor. From these results, it is considered that only one thiol group exists near the binding site of the mu receptor in GPI. Similar results were also obtained for the mu receptors in mouse vas deferens.     

Effect of exercise-induced acidosis on aldosterone secretion in men

The present study was carried out to elucidate whether an exercise-induced increase in plasma hydrogen ion concentration influences aldosterone secretion. Six healthy men (aged 22–25 years) performed two intermittent exercise tests with and without drug administration. The intensities of these exercise tests were 40% maximal oxygen uptake (V˙O_2max) and 90% V˙O_2max, respectively. Administration of 2-mg Dexamethasone and 50-mg Captopril caused an almost complete suppression of adrenocorticotropic hormone (ACTH) and an enhancement of the elevation in renin concentration during exercise, indicating successful inhibition of ACTH release and angiotensin II production during exercise. While the magnitude of the increase in aldosterone in the drug experiment was depressed compared with the control experiment, a significant increase in aldosterone concentration was observed at the end of the 90% V˙O_2max exercise. Whilst the change in aldosterone concentration did not correlate with the change in plasma potassium concentration, there was a significant correlation between aldosterone and plasma hydrogen ion concentrations in the drug experiment. Since the correlation coefficient was low (r=0.455), the biological meaning of this correlation should be further investigated. These results would suggest that an elevation of plasma hydrogen ion concentration induced by exercise per se appears to be related, at least in part, with increased aldosterone secretion, independent of the pituitary-adrenal axis, and the renin-angiotensin system. Accepted: 23 September 1997     

Mechanism for the regulation of mammalian cGMP phosphodiesterase6. 2: Isolation and characterization of the transducin-activated form

Rod photoreceptor cGMP phosphodiesterase (PDE6) consists of a catalytic subunit complex (Pαβ) and two inhibitory subunits (Pγ). In the accompanying article, using bovine photoreceptor outer segment homogenates, we show that Pγ as a complex with the GTP-bound transducin α subunit (GTP-Tα) dissociates from Pαβγγ on membranes, and the Pαβγγ becomes Pγ-depleted. Here, we identify and characterize the Pγ-depleted PDE. After incubation with or without guanosine 5′-O-(3-thiotriphosphate) (GTPγS), Pαβ complexes are extracted. When a hypotonic buffer is used, Pαβγγ, Pαβγ, and a negligible amount of a Pαβ complex containing Pγ are isolated with GTPγS, and only Pαβγγ is obtained without GTPγS. When an isotonic buffer containing Pδ, a prenyl-binding protein, is used, Pαβγγδ, Pαβγδδ, and a negligible amount of a Pαβ complex containing Pγ and Pδ are isolated with GTPγS, and Pαβγγδ is obtained without GTPγS. Neither Pαβ nor Pαβγγ complexed with GTPγS-Tα is found under any condition we examined. Pαβγ has ~12 times higher PDE activity and ~30 times higher Pγ sensitivity than those of Pαβγγ. These results indicate that the Pγ-depleted PDE is Pαβγ. Isolation of Pαβγγδ and Pαβγδδ suggests that one C-terminus of Pαβ is involved in the Pαβγγ interaction with membranes, and that Pγ dissociation opens another C-terminus for Pδ binding, which may lead to the expression of high PDE activity. Cone PDE behaves similarly to rod PDE in the anion exchange column chromatography. We conclude that the mechanisms for PDE activation are similar in mammalian and amphibian photoreceptors as well as in rods and cones.     

Syntheses of two trimannose analogs each containing C-mannosyl or 5-thio-C-mannosyl residue: their affinities to concanavalin A

C-Mannosyl residue-containing trimannose ManC alpha(1,6)[Man alpha(1,3)Man] (2) and 5-thio-C mannosyl residue-containing trimannose 5SManC alpha(1,6)[Man alpha(1,3)Man] (3) were synthesized via a glycosyl radical addition to enone derivative of mannose (6). Dissociation constants for the binding of these trisaccharides to concanavalin A (ConA) were determined by a fluorescence anisotropy inhibition assay: Kd = 198 and 31 microM, respectively. The unexpectedly large Kd value for the compound 2 compared with the compound 3 and the natural trimannose 1 demonstrates a characteristic of C-glycoside.     

Alkaline Catalase Produced by Bacillus No. Ku-1

Bacillus No. Ku-1 isolated from soil produced and alkaline catalase in alkaline media. The characteristic point of this bacteria was especially good growth in alkaline media. The alkaline catalase in the culture fluid was purified by DEAE-cellulose and Sephadex columns. The enzyme was most active at pH 10.0 and was stable at pH 7.0 to 8.5. The sedimentation constant was about 12.5 S. The enzyme was strongly inhibited by NaN₃, KCN, FeSO₄ and Fe₂ (SO₄)₃. Properties of the enzyme are almost same as those of catalases so far reported except optimum pH for enzyme action and Kat.f. value (4.4×10⁴).