Clinical evaluation of brushing time and plaque removal potential of two manual toothbrushes

Abstract: Aim: To compare plaque removal efficacy of Oral‐B CrossAction (CA) used for 1 min with an American Dental Association (ADA) manual toothbrush used for 2 or 5 min in an examiner‐blind, three‐treatment, six‐period crossover study. Materials and methods: After refraining from all oral hygiene procedures for 23–25 h, subjects were randomly assigned to one of nine possible six‐period (visit) treatment sequences. Plaque was assessed at baseline (Rustogi Modified Navy Plaque Index). Post‐brushing scores were recorded after brushing with a marketed dentifrice and the assigned toothbrush for the specified duration. The same procedure was followed at each of six subsequent visits. Clinical measurements were carried out by the same examiner. Results: Forty subjects completed the study. All three treatments effectively removed plaque from the whole mouth, along the gingival margin and from approximal surfaces. Whole mouth and gingival margin plaque removal scores with CA for 1 min did not differ significantly from scores with the ADA toothbrush used for 2 min. The ADA brush used for 5 min showed significantly greater whole mouth (P < 0.001) and gingival margin (P < 0.001) plaque reduction than the two other treatments. Approximal plaque removal scores did not differ between the three treatments. Conclusions: Efficient plaque removal can be achieved after 1 min of brushing with CA. The amount of plaque removed did not differ significantly from that achieved with the ADA brush after 2 min of brushing. Greater whole mouth and gingival margin plaque removal scores were seen with the ADA brush after 5 min.     

Respiratory insufficiency in neuronopathic and neuropathic disorders

Twenty-nine patients with a neuronopathic or neuropathic disorder were referred for assessment of respiratory insufficiency between 1978 and 1994. Diagnoses included spinal muscular atrophy (6), chronic idiopathic demyelinating neuropathy (4), Vialetto-van Laere syndrome (3), hereditary motor and sensory neuropathy (3) and a miscellaneous group (5). We also describe seven patients with Guillain-Barre syndrome (GBS) who required long-term ventilatory support for over 6 months to 7 years after the initial illness. Respiratory insufficiency occurred as a consequence of respiratory muscle weakness, impaired bulbar function and restrictive lung defects. In some groups presentation was with progressive nocturnal hypoventilation culminating in acute respiratory failure. Five patients with GBS or chronic idiopathic demyelinating neuropathy were weaned from ventilatory support up to 18 months after the initial illness. The remaining 24 patients required continuous or nocturnal ventilatory support using intermittent positive-pressure ventilation (13), negative pressure ventilation (4), nasal-mask-delivered intermittent positive-pressure ventilation (4), nasal-mask-delivered continuous positive-pressure ventilation (3), mouthpiece-assisted ventilation by day (2) and rocking bed (1). None have been weaned from support after a period of ventilation ranging from one month to 10 years. Eight patients have subsequently died.      

A sterically stabilized immunolipoplex for systemic administration of a therapeutic gene

A sterically stabilized immunolipoplex (TsPLP), containing an antitransferrin receptor single-chain antibody fragment (TfRscFv)-PEG molecule, has been developed to specifically and efficiently deliver a therapeutic gene to tumor cells. A postcoating preparation strategy was employed in which a DNA/lipid complex (lipoplex) was formed first and then sequentially conjugated with PEG and TfRscFv. The complex prepared by this method was shown to be superior in ability to deliver genes to tumor cells than when prepared by a common precoating strategy, in which DNA is mixed with TfRscFv-PEG conjugated liposome. Using prostate cancer cell line DU145, a comparison was made between the in vitro and in vivo gene delivery efficiencies of four complexes, Lipoplex (LP), PEG-Lipoplex (PLP), TfRscFv-PEG-Lipoplex (TsPLP) and our standard TfRscFv-Lipoplex (TsLP). In vitro, the order of transfection efficiency was TsLP>LP approximately TsPLP>PLP. However, in vivo the order of transfection efficiency, after systemic administration via the tail vein, was TsPLP>TsLP>LP or PLP with TsPLP-mediated exogenous gene expression in tumor being two-fold higher than when mediated by TsLP. This suggests that the in vitro transfection efficiency of TsPLP was not indicative of its in vivo efficiency. In addition, it was found that the level of exogenous gene expression in the tumor mediated by TsPLP was higher than that mediated by TsLP and did not decrease over the time. More importantly, high exogenous gene expression in tumor, but low expression in liver, was observed after an i.v. delivery of TsPLP carrying either the GFP reporter gene or the p53 gene, indicating that tumor preferential targeting was maintained by this complex in the presence of PEG. These findings show that incorporation of PEG into our targeted lipoplex results in a more efficient delivery of the complex to the tumor cells, possibly by inhibiting the first pass clearance observed with non-PEG containing liposomes. Therefore, these data demonstrate that TsPLP is a improvement over our previously established tumor targeted gene delivery complex for systemic gene therapy of cancer.     

The impact of donor age and sex on the nucleated cell count and CD34 count in healthy bone marrow donors

BM remains an important source of stem cells. The BM characteristics change with age but the estimation of CD34 calculation of one CD34+ cell per 100 nucleated cells is used for all donors including pediatric donors in the operating room before getting the actual CD34 count. In order to see whether this formula is applicable for pediatric donors, we designed a retrospective study to see the affect of the age and sex on the BM NCC, CD34 count, and CD34/NCC ratios. Ninety‐eight BM collections from 91 related donors were evaluated retrospectively (median age: nine yr [1.5–54 yr]; M/F: 41/50). A significant negative correlation was found between the donor age and NCC (r = −0.229, p < 0.05), CD34 count (r = −0.563, p < 0.01), and CD34/NCC (r = −0.664, p < 0.01). The negative correlation for CD34 count and CD34/NCC persisted in female and male donor groups. When donors younger than 16 yr of age were compared with the older donor group, the median NCC, median CD34 count, and CD34/NCC were significantly lower in the older group (p < 0.01). Age and sex have to be taken into consideration to avoid unnecessary high‐volume collections and increased operating room time in the younger donors.     

Incidence of malignant pleural mesothelioma due to environmental asbestos fiber exposure in the southeast of Turkey

BACKGROUND: Inhabitants of the southeast of Turkey (ST) have been exposed since childhood to inhalation of asbestos, from a material containing tremolite, used for whitewashing. This has resulted in an increased incidence of malignant pleural mesothelioma (MPM). OBJECTIVES: To review the epidemiological features of MPM cases in ST; to calculate and compare the incidence with the previously reported ones. SUBJECTS AND METHODS: The study included 176 MPM cases from different places in ST. The incidence of MPM was calculated for those places according to the distribution of the cases. RESULTS: In the previously identified regions of asbestos (region 1) where the population had been informed of the danger with the soil some decades ago, the MPM incidence was decreased, as compared to the previous reports. The annual incidence of MPM in these places was found to be 42.9 per million in this study while it had been reported to be 105.5 per million in the previous studies. In contrast, the incidence that was reported previously to be 2.75 per million in the regions where asbestos exposure had not been identified before (region 2) was found to be 8.6 per million in this study. In region 2 the incidence of MPM increased even in the second half of the last decade (5.9 versus 11.9 per million). CONCLUSIONS: Use of asbestos-containing soil continues in different places in ST. Even if the use of this soil is abandoned today, MPM will be an important health problem in this region till the third or fourth decades of this century. Informing the villagers of the danger and preventing the use of this soil may result in a considerable decrease in the incidence of MPM.     

Therapy of acute hepatitis C with interferon-alpha2b plus ribavirin in a health care worker

Hepatitis C virus can be transmitted to health care workers through needlestick accidents. In this report, the result of short-term therapy with interferon-alpha2b plus ribavirin combination of acute hepatitis C in a health care worker who infected through laboratory accident was presented. The patient received combination of interferon-alpha2b (5 MU three times a week) plus ribavirin (1000 mg daily) for three months. Aminotransferase levels were normalised and clearance of HCV RNA was obtained in the first month of the therapy. After 19 months of follow-up, he had undetectable levels of HCV RNA so sustained response (clearance of HCV RNA and normalisation of aminotransferases at least six months after cessation of therapy) was achieved. According to this result, short-term therapy of acute hepatitis C with interferon-alpha2b plus ribavirin may be an alternate to others.     

Implausibility of the vibrational theory of olfaction

The vibrational theory of olfaction assumes that electron transfer occurs across odorants at the active sites of odorant receptors (ORs), serving as a sensitive measure of odorant vibrational frequencies, ultimately leading to olfactory perception. A previous study reported that human subjects differentiated hydrogen/deuterium isotopomers (isomers with isotopic atoms) of the musk compound cyclopentadecanone as evidence supporting the theory. Here, we find no evidence for such differentiation at the molecular level. In fact, we find that the human musk-recognizing receptor, OR5AN1, identified using a heterologous OR expression system and robustly responding to cyclopentadecanone and muscone, fails to distinguish isotopomers of these compounds in vitro. Furthermore, the mouse (methylthio)methanethiol-recognizing receptor, MOR244-3, as well as other selected human and mouse ORs, responded similarly to normal, deuterated, and ¹³C isotopomers of their respective ligands, paralleling our results with the musk receptor OR5AN1. These findings suggest that the proposed vibration theory does not apply to the human musk receptor OR5AN1, mouse thiol receptor MOR244-3, or other ORs examined. Also, contrary to the vibration theory predictions, muscone-d₃₀ lacks the 1,380- to 1,550-cm⁻¹ IR bands claimed to be essential for musk odor. Furthermore, our theoretical analysis shows that the proposed electron transfer mechanism of the vibrational frequencies of odorants could be easily suppressed by quantum effects of nonodorant molecular vibrational modes. These and other concerns about electron transfer at ORs, together with our extensive experimental data, argue against the plausibility of the vibration theory.In 1870, the British physician William Ogle wrote: “As in the eye and the ear the sensory impression is known to result not from the contact of material particles given off by the object seen or heard, but from waves or undulations of the ether or the air, one cannot but suspect that the same may be true in the remaining sense, and that the undulatory theory of smell… [may be] the true one” (1, 2). Of the 29 different “theories of odour” listed in the 1967 edition of The Chemical Senses (3), nine associate odor with vibrations, particularly those theories championed by Dyson (4, 5) and Wright (6–8). However, the premise that olfaction involves detection of vibrational frequencies of odorants remains highly speculative because neither the structures of the odorant receptors (ORs) nor the binding sites or the activation mechanisms triggered upon odorant binding to ORs have been established. In 1996–1997, Turin (9–12) elaborated on the undulatory theory of smell, as considered in more detail below, and suggested that a mechanism analogous to inelastic electron tunneling spectroscopy (13) may be involved, where tunneling electrons in the receptor probe the vibrational frequencies of odorants. In 2013, Gane et al. (14) commented that “whether olfaction recognizes odorants by their shape, their molecular vibrations, or both remains an open and controversial question” and that “a convenient way to address [this question] is to test for odor character differences between deuterated and nondeuterated odorant isotopomers since these have identical ground-state conformations but different vibrational modes.” Gane et al. (14) also stated that a particularly appropriate test case would involve odorants containing “more CH group… [such as] musks [which] are among the largest odorants and typically contain 15–18 carbons and 28 or more hydrogens.”In judging the plausibility of the vibration theory, we use a multipronged approach:

• i)We consider the concepts of shape vs. vibration theory and odorant perception vs. reception.
• ii)As a test of the vibration theory, we have prepared a series of isotopomers of musks and other compounds, containing up to 30 C–H or C–D bonds as test odorants, which are evaluated using in vitro activation of receptors identified by us and other groups as being highly responsive to these isotopomers.
• iii)We consider the confounding effects of impurities and isotope effects in interpreting odorant perception, as well as the validity of requirements for specific IR bands for recognition of musks by their receptors.
• iv)We examine the physical validity of the models developed to support the vibration theory.
• v)We consider the specific limitations of our in vitro approach using isotopomers to evaluate the vibration theory, based primarily on results obtained with a single identified human musk OR, in addition to other OR/ligand pairs.
• vi)We consider plausible nonvibration theory models for docking of musks to the human musk receptor, OR5AN1, where the musk carbonyl group functions as a hydrogen bond acceptor.

Gane et al. (14) have framed the argument for olfactory discrimination of hydrogen isotopomers as one of “shape” vs. “vibration.” However, neither the binding modes of isotopomers nor their activation mechanisms are known. ORs belong to the superfamily of class A G protein-coupled receptors (GPCRs), which are known to be activated through allosteric conformational changes induced upon ligand binding even without triggering any kind of electron transfer processes. Ligand–receptor interactions can be both attractive and repulsive, involving hydrogen bonding, van der Waals, cation–π, π–π, ion–ion, dipole–dipole, steric, and hydrophobic interactions with the receptor, with water channels and bridging water molecules mediating hydrogen bonds, as well as metal–ion coordination, as we have recently demonstrated in the latter case (15, 16). Therefore, molecular shape can be considered a “straw-man” alternative to the vibration theory when describing the differing affinities of ligands bound to GPCRs (17, 18), including isotopomers (19, 20). Some of these attractive and repulsive interactions were identified in 1940 by Pauling and Delbrück (21), who note that interacting biomolecules “must have complementary surfaces, like die and coin, and also a complementary distribution of active groups.” In addition, shape-related features are misrepresented by vibration theory proponents. For example, Franco et al. (17) stated: “Given that proteins are chiral, a shape-only theory cannot account for the identical odors of most enantiomeric pairs,” echoing similar comments by Turin (22): “One would therefore generally expect enantiomers to have completely different smells. This is emphatically not the case.” However, these assertions are clearly at odds with the highly developed ability of mice and other mammals to discriminate an array of nonpheromonal chiral odorant enantiomeric pairs (23–25), with the divergent in vitro responses to enantiomers by different combinations of ORs (26) and, in particular, with the highly selective response of the musk-sensitive mouse receptor, MOR215-1, to (R)-muscone (“l-muscone”) compared with (S)-muscone (“d-muscone”) (27).In addition to our concerns regarding shape, a second issue relates to describing how different smells are perceived, that is, the perception of an odorant. It is known that in vivo perception of odorants reflects the totality of perireceptor events as well as odorant–OR interactions (reception). Volatile odorants enter the nasal passage, where they dissolve in the nasal mucus overlying the olfactory epithelium and are then rapidly detected by ORs on the cilia of the olfactory sensory neurons, ultimately leading to signaling (28, 29). It is the mechanism of odorant–OR interactions, the reception of the odorant, that we seek to examine with isotopomers to determine whether the vibration theory is plausible, displaying isotope effects, because perception could be influenced by isotope effects due to the perireceptor events involving mucosal components, such as enzymes, mucopolysaccharides, salts, and antibodies.Whether deuterated and nondeuterated odorant isotopomers can be distinguished by smell and, even if they can, whether this distinction validates the vibration theory is a matter of contention. A 2001 paper by Haffenden et al. (30) reported that benzaldehyde-d₆ gave a statistically significant difference in odor perception relative to normal benzaldehyde, in support of the vibration theory. However, this study has been criticized for lacking double-blind controls to eliminate bias and because it used an anomalous version of the duo-trio test (31). Furthermore, the study failed to account for perireceptor events, namely, the enzyme-mediated conversion of odorants that has been shown to occur in nasal mucus. For example, benzaldehyde is converted to benzoic acid (32), a reaction potentially subject to significant primary isotope effects (2, 33, 34), which could explain the difference in odor perception for the benzaldehyde isotopomers. Earlier claims that human subjects can distinguish odors of acetophenone isotopomers (9, 35) have been shown to be untrue (14, 31). Recent studies indicate that Drosophila melanogaster can distinguish acetophenone isotopomers (36, 37) and that Apis mellifera L., the honey bee, can be trained to discriminate pairs of isotopomers (38). These studies differ from earlier insect studies in which isotopomer discrimination was not found. For example, systematic deuteration of 4-(p-hydroxyphenyl)-2-butanone acetate, a Dacus cucurbitae Coquillett (the male melon fly) attractant, did not affect the attractiveness of the compound to the fly (39); deuteration of alarm pheromones failed to alter the response toward these compounds by Pogonomyrmex badius worker ants (40); and honey bees could not distinguish between deuterated and nondeuterated nitrobenzene (41).Concerns have been raised (42) about aspects of the Drosophila study (36), which is “behavioural and not at the receptor level” (2) (also a concern with the Apis study). Also, given that the ORs and their downstream signaling in Drosophila and humans are completely unrelated, the Drosophila study should not be considered predictive of the ability of humans to distinguish isotopomers (2, 17). In view of the above discussion, it is interesting that in a blinded behavioral study, smell panelists distinguished between deuterated and nondeuterated isotopomers of cyclopentadecanone (1; Fig. 1A) and other musk odorants (14).Open in a separate windowFig. 1.(A) Preparation of deuterated 1–3. Deuterium could be selectively introduced, or selectively removed, adjacent to the carbonyl group using D₂O/K₂CO₃ or H₂O/K₂CO₃, respectively, at 130 °C; global replacement of all hydrogens could be achieved with Rh/C in D₂O at 150 °C. Repetition led to more complete deuteration as well as reduction of 1 to 3 and 2; oxidation of 2 gave 1 with ∼98% deuteration. Chromatography of deuterated 1 with freshly distilled pentane followed by repeated recrystallization from methanol/water to constant melting point gave samples showing no new peaks in their ¹H NMR spectra, other than very weak peaks corresponding to those peaks seen in undeuterated 1. (B) Deuterated (97%) muscone 4 was prepared via alcohol 5 as above. (C) 8-d₅ and 2,4,5,7-tetrathiaoctane-d_10, (9-d₁₀; 98% deuterium) were prepared as shown. Details of these syntheses are provided in SI Appendix.Here, we study the response of human musk-sensitive OR5AN1, identified through screening of heterologously expressed human ORs, to cyclopentadecanone (1) and muscone (4) isotopomers. We also present pharmacological data on the response of mouse ORs to deuterated and nondeuterated acetophenone and benzaldehyde, as well as selected ¹³C isotopomers. In addition, we present related studies on the response of various human and mouse ORs to other deuterated and nondeuterated odorants, including (methylthio)-methanethiol (MTMT, 8; Fig. 1C) and bis(methylthiomethyl) disulfide (9), studied in connection with our investigation of the role of copper coordination in the recognition of both sulfur-containing odorants by the mouse (methylthio)methanethiol receptor, MOR244-3 (15, 16). Insofar as the ability to distinguish odors of isotopomers directly tests the predictions of the vibration theory, the comparative response of human and mouse ORs to isotopomers of these selected ligands in the heterologous OR expression system constitutes a robust test of the vibration theory. Finally, we discuss the basis for recent vibration theories of olfaction and supporting computational evidence (37, 43–47) in light of well-established electron transfer theories (48). We point out that key assumptions underlying the vibration theory lack experimental support and are missing important physical features expected for biological systems.