The αGal HyperAcute(®) Technology: enhancing immunogenicity of antiviral vaccines by exploiting the natural αGal-mediated zoonotic blockade

The αGal HyperAcute(®) Technology exploits a robust zoonotic blockade to enhance potency of antiviral vaccines. Naturally acquired immunity against the common αGal epitope [galactose-alpha(1,3)-galactose-beta(1,4)N-acetylglucosamine-R (Gal-α(1,3)-Gal-β(1,4)-GlcNAc-R)] is facilitated by the loss of a key enzyme in the epitope's biosynthetic pathway. As human cells are devoid of this epitope, chronic stimulus from gut flora leads to high levels of circulating anti-αGal antibodies and the development of a robust immune pathway. As the αGal epitope is immediately recognized as foreign, the naturally acquired αGal immune pathway in humans serves as a strong barrier to zoonotic infection. The αGal HyperAcute(®) Technology takes advantage of this natural process to facilitate the rapid presentation of modified antigens to antigen-presenting cells, leading to a strong immune response. The evolutionary immunity to αGal ensures that the presence of αGal epitopes on antigens will lead to a robust immune response involving cross-activation of T(H)1 immunity, characterized by cytokine secretion and increased phagocytic activity, and T(H)2 immunity characterized by high antibody titres. αGal epitopes can be applied to antiviral vaccines by biological, enzymatic or chemical means. Several detection methods that directly and indirectly verify αGal addition are discussed. Enhanced immunogenicity (humoral and cellular) of αGal-modified vaccines is shown for several antiviral vaccine candidates. αGal modification of antiviral vaccine components leads to enhanced immunogenicity. The existing body of literature describing the utility of αGal epitopes as a safe and robust immunostimulatory and -modulatory agent in humans supports the basis for applying the αGal HyperAcute(®) Technology to the improvement of antiviral vaccines, both new and currently approved.

Effect of liver X receptor activation on the very low density lipoprotein secretion and messenger ribonucleic acid level of related genes in goose primary hepatocytes

In this study, we investigated the role of liver X receptor (LXR) activation in hepatic assembly and in the secretion of very low density lipoprotein-triglycerides in goose primary hepatocytes. Goose primary hepatocytes were isolated and treated with the LXR agonist T0901317. Total triglyceride accumulation, intracellular and extracellular triglyceride concentrations, extracellular very low density lipoprotein concentration, and gene expression levels of LXRα, microsomal triglyceride transfer protein, acyl coenzyme A:diacylglycerol acyltransferase (DGAT) 1, and DGAT2 were measured in primary hepatocytes. We found a dose-dependent upregulation of total and intracellular TG accumulation when using 0, 0.01, 0.1, 1, and 10 μM T0901317, but the extracellular triglyceride and very low density lipoprotein concentrations were dose dependent only when the T0901317 concentration was below 1 μM; as compared with 1 μM T0901317, 10 μM T0901317 had an inhibiting effect (P < 0.05). The mRNA levels of all the detected genes increased in the presence of T0901317. The change in LXRα and DGAT1 was dose dependent, and the mRNA levels of microsomal triglyceride transfer protein and DGAT2 increased with a T0901317 concentration up to 1 μM, but decreased when treated with 10 μM T0901317 (P < 0.05). In conclusion, the secretion of very low density lipoprotein plays a role in pharmacologically activating the LXR-induced development of hepatocellular steatosis in geese.

Molecular characterization and structure analysis of RPL10/QM-like protein from the red drum Sciaenops ocellatus (Sciaenidae)

The QM-like gene encodes a ribosomal protein L10. Besides housekeeping roles in protein synthesis, QM-like proteins have multiple extraribosomal functions during cell growth, cell differentiation and apoptosis. We obtained the full-length cDNA of QM-like protein (designated as SoQM) from the salt water game fish Sciaenops ocellatus, using RACE-PCR. The sequence consists of 740 bp, encoding 215-amino acid residues with 24.60 kDa. The AA sequence of the SoQM protein contains a series of functional motifs that belong to the QM family signature, which is conserved among different species. The SoQM gene contains five introns and six exons. The expression pattern of SoQM as determined by RT-PCR indicated that SoQM mRNA was expressed in all tissues tested, including brain, gill, head-kidney, intestine, stomach, heart, spleen, blood, muscle, and gonads. The phylogenetic tree constructed with MEGA 4.0 showed that SoQM clusters together with that of other fish. It was found that the sequences of the SoQM gene are highly conserved, suggesting the fundamental and critical functions of SoQM in S. ocellatus. The three-dimensional structure of the SoQM protein core domain (4~169) was predicted by the Swiss-Model program. Compared with QM proteins in other species, the main structure of SoQM protein was conserved, while the C-terminal domain was different from other QM-like proteins. Prediction of the three-dimensional structure of SoQM would provide valuable insight into the molecular basis of protein function, allowing an effective design of experiments, such as site-directed mutagenesis, studies of disease-related mutations or structure-based design of specific inhibitors.

A new approach to quantifying morphological variation in bluegill Lepomis macrochirus

Bluegill Lepomis macrochirus showed intraspecific morphological and behavioural differences dependent on the environment. Pelagic L. macrochirus had more fusiform bodies, a higher pectoral fin aspect ratio, a larger spiny dorsal fin area and pectoral fins located farther from the centre of mass than littoral L. macrochirus (P < 0·05). The shape of the body and pectoral fins, in particular, were suggestive of adaptation for sustained high-speed and economical labriform swimming. Littoral L. macrochirus had a deeper and wider body, deeper caudal fins and wider mouths than pelagic L. macrochirus (P < 0·05). Additionally, the soft dorsal, pelvic, anal and caudal fins of littoral L. macrochirus were positioned farther from the centre of mass (P < 0·05). The size and placement of these fins suggested that they will be effective in creating turning moments to facilitate manoeuvring in the macrophyte-dense littoral habitat.

Polymer nanocomposites exhibiting magnetically tunable microwave properties

Polymer nanocomposites (PNCs) have been synthesized using Rogers polymer and CoFe₂O₄ nanoparticles (CFO NPs). X-ray diffraction (XRD) confirms the inverse spinel crystal structure of CFO NPs and transmission electron microscopy (TEM) images show the uniform dispersion of nanoparticles (10 nm ± 1) into the polymer matrix. Magnetic measurements indicate superparamagnetic response near room temperature for all PNCs. A blocking temperature T(B)~298 K was observed and does not vary for different loading fractions of CFO NPs for the PNCs. The saturation magnetization (M(s)) was found to be 11 emu g⁻¹ for 30 wt% CFO, increasing to 32 emu g⁻¹ for the 80 wt% CFO loaded PNC. A large value of coercivity (H(c) = 19 kOe) is also observed at 10 K and is not affected by varying CFO loading. Microwave measurements show significant absorption in the 80 wt% CFO loading PNC and the quality factor shows a strong enhancement with applied magnetic field.

Effects of chronic administration of alogliptin on the development of diabetes and β-cell function in high fat diet/streptozotocin diabetic mice

AIM

Alogliptin is a potent and highly selective dipeptidyl peptidase-4 (DPP-4) inhibitor. The aim of this study was to determine its effects on glucose control and pancreas islet function and to identify the underlying molecular mechanisms after chronic administration, in a non-genetic mouse model of type 2 diabetes.

METHODS

Alogliptin (5, 15 and 45 mg/kg) was orally administered to high fat diet/streptozotocin (HFD/STZ) diabetic mice daily for 10 weeks. Postprandial and 6-h fasting blood glucose levels, blood A1C level, oral glucose tolerance and pancreas insulin content were measured during or after the treatment period. Alogliptin plasma concentration was determined by an LC/MS/MS method. Islet morphology and architectural changes were evaluated with immunohistochemical analysis. Islet endocrine secretion ability was assessed by measuring insulin release from isolated islets which were challenged with 16 mM glucose and 30 mM potassium chloride, respectively. Gene expression profiles of the pancreas were analysed using the mouse diabetes RT(2) Profiler PCR array which contains 84 genes related to the onset, development and progression of diabetes.

RESULTS

Alogliptin showed dose-dependent reduction of postprandial and fasting blood glucose levels and blood A1C levels. Glucose clearance ability and pancreas insulin content were both increased. Alogliptin significantly restored the β-cell mass and islet morphology, thus preserving islet function of insulin secretion. Expression of 10 genes including Ins1 was significantly changed in the pancreas of diabetic mice. Chronic alogliptin treatment completely or partially reversed the abnormalities in gene expression.

CONCLUSIONS

Chronic treatment of alogliptin improved glucose control and facilitated restoration of islet architecture and function in HFD/STZ diabetic mice. The gene expression profiles suggest that the underlying molecular mechanisms of β-cell protection by alogliptin may involve alleviating endoplasmic reticulum burden and mitochondria oxidative stress, increasing β-cell differentiation and proliferation, enhancing islet architecture remodelling and preserving islet function.

Association of olfactory bulb volume and olfactory sulcus depth with olfactory function in patients with Parkinson disease

BACKGROUND AND PURPOSE

Olfactory dysfunction is commonly associated with IPD. We here report the association of OB volume and OS depth with olfactory function in patients with PD.

MATERIALS AND METHODS

Morphometric analyses by using MR imaging and the Japanese T&T olfactometer threshold test were used to evaluate olfactory structure and function in 29 patients with PD and 29 age- and sex-matched healthy controls.

RESULTS

The olfactory recognition thresholds were significantly higher in patients with PD than in healthy controls (3.82 ± 1.25 versus 0.45 ± 0.65, P<.001). Olfactory atrophy with reductions in the volume of the OB (37.30 ± 10.23 mm(3) versus 44.87 ± 11.84 mm(3), P<.05) and in the depth of OS (8.90 ± 1.42 mm versus 9.67 ± 1.24 mm, P<.05) was observed in patients with PD but not in controls. Positive correlations between olfactory performance and OB volumes were observed in both patients with PD (r=-0.45, P<.0001) and in controls (r=-0.42, P<.0001). In contrast, there was no significant correlation between the depth of OS and olfactory function in either cohort.

CONCLUSIONS

The results provide evidence that early olfactory dysfunction in patients with PD may be a primary consequence of damage to the OB. Neuroimaging of olfactory structures together with the assessment of olfactory function may be used to identify patients with PD.

The fatigue resistance of rabbit tibiae varies with age from youth to middle age

Young adults are at risk of stress fractures. Risk is higher in younger and female individuals. Stress fractures occur due to repeated loading of the bone (fatigue). We modeled this with rabbit tibiae. Age increased fatigue resistance which correlated with bone mineral density. A sex difference was not detected.

INTRODUCTION

Younger adults who engage in intense physical activity with a sudden increase in intensity level (military recruits/college athletes) are at risk of bone stress fractures. Risk is greater in females and diminishes with aging. Stress fractures may be the result of fatigue damage, which is not repaired rapidly enough to avoid fracture. It was hypothesized that the fatigue resistance of whole rabbit tibiae would be less in female specimens but greater as animal age increased.

METHODS

Rabbit tibiae were harvested from three age groups (4, 7, and ≥ 12 months (females only)). The tibiae were scanned with dual energy X-ray absorptiometry to determine bone mineral density (BMD), computed tomography to quantify geometry, and then fatigue tested in three-point bending.

RESULTS

In the ≥ 12-month group, BMD was approximately 20% higher, while the fatigue resistance was found to be approximately ten times higher than the other age groups. Sex was not a factor in the 4- and 7-month groups. Multiple linear regression revealed that fatigue life was negatively correlated with applied stress range and positively correlated with BMD (adjusted r (2) = 0.69).

CONCLUSIONS

A difference in fatigue behavior due to sex was not detected, but there was a large increase in fatigue resistance with age. This correlated with increased BMD and parallels a reduced risk of stress fracture due to age in military recruits. Skeletal "maturation" may play an important role in determining stress fracture risk. Increased risk in females may be due to mechanisms other than those that determine material behavior.

Dijet azimuthal decorrelations in pp collisions at √s=7 TeV

Measurements of dijet azimuthal decorrelations in pp collisions at √s=7 TeV using the CMS detector at the CERN LHC are presented. The analysis is based on an inclusive dijet event sample corresponding to an integrated luminosity of 2.9 pb⁻¹. The results are compared to predictions from perturbative QCD calculations and various Monte Carlo event generators. The dijet azimuthal distributions are found to be sensitive to initial-state gluon radiation.

Clival invasion on multi-detector CT in 390 pituitary macroadenomas: correlation with sex, subtype and rates of operative complication and recurrence

BACKGROUND AND PURPOSE

Clival invasion, a rare but potentially significant complication of pituitary adenoma, is difficult to detect on MR imaging. Because CT is widely used in adjunct guidance of pituitary surgery and it has recently been suggested that preoperative CT may add useful diagnostic information in addition to pituitary MR imaging, we performed the first large cross-sectional imaging study to define the image attributes, clinical correlates, and prognostic implications of clival invasion on CT for pituitary adenoma surgical guidance.

MATERIALS AND METHODS

Preoperative CT images from 390 patients with histopathologically diagnosed pituitary macroadenoma were reviewed retrospectively and classified by the presence and degree of clival invasion. Tumor volume, tumor subtype, patient sex, operative complication, and recurrence rates were compared between groups.

RESULTS

After we corrected for multiple correlations, the most significant independent risk factor for clival invasion was female sex (OR=3.62, P=.014, multinomial logistic regression), followed by large tumor volume (OR=1.08, P<.001), and null-cell subtype (OR=5.47, P<.001). Larger tumor volume correlated with null-cell subtype (Mann-Whitney U test, P=.006), incidence of clival invasion (P<.001), and extent of clival invasion (P=.038). Clival invasion was associated with a significantly higher ratio of operative complications (15.63%, χ(2)=7.067, P=.008) and recurrence (57.14%, χ(2)=10.739, P=.001).

CONCLUSIONS

CT detection of clival invasion by pituitary macroadenoma is significantly more common in women, in patients with large tumors, and in patients with null-cell tumors, and it is associated with a higher rate of operative complications and recurrences. Attention to the presence of clival invasion on preoperative CT and prospective investigation of its prognostic significance are indicated. Attention to this finding on pituitary guidance CT is warranted.

Measurement of the B(+) production cross section in pp collisions at sqrt[s]=7 TeV

Measurements of the total and differential cross sections dσ/dp(T)(B) and dσ/dy(B) for B(+) mesons produced in pp collisions at sqrt[s]=7  TeV are presented. The data correspond to an integrated luminosity of 5.8  pb(-1) collected by the CMS experiment operating at the LHC. The exclusive decay B(+)→J/ψK(+), with J/ψ→μ(+)μ(-), is used to detect B(+) mesons and to measure the production cross section as a function of p(T)(B) and y(B). The total cross section for p(T)(B)>5  GeV and |y(B)|<2.4 is measured to be 28.1±2.4±2.0±3.1  μb, where the first uncertainty is statistical, the second is systematic, and the last is from the luminosity measurement.

Effect of exercise training intensity on murine T-regulatory cells and vaccination response

To understand the underlying mechanism(s) for the effect of exercise at different intensities on T cell and DNA vaccination responses, we treated mice in a training protocol with regular moderate-intensity exercise (MIE) or prolonged, exhaustive high-intensity exercise (HIE). After 6 weeks of training, splenocytes were isolated to evaluate cytokine expression and T-regulatory (Treg) cell proportion by RT-PCR and FACS, respectively. Another set of mice that completed the same training protocol were used to determine DNA vaccination responses. These mice were immunized three times with HBV DNA vaccine at 2-week intervals and euthanized on day 14 after the last immunization. Serum and splenocytes were isolated to determine humoral and cell-mediated immunity (CMI). Results showed that HIE increased anti-inflammatory cytokine expression and CD4(+) CD25(+) Treg cell proportion. Further, HIE decreased IFN-γ expression, T-lymphocyte proliferation, and antigen-specic cytotoxic response in HBV DNA vaccine-immunized mice. MIE did not change anti-inflammatory cytokine expression or CD4(+) CD25(+) Treg cell proportion but increased pro-inflammatory cytokine expression and augmented antigen-specific CMI. Thus, MIE lower the risk of cancer and infectious illness through enhancing the pro-inflammatory responses. By contrast, HIE might increase the risk of common infections, such as upper respiratory tract infection, due to an up-regulation of CD4(+) CD25(+) Treg cells and anti-inflammatory responses.

In Vivo Stress Analysis of a Pacing Lead From an Angiographic Sequence

In this paper, a method is presented to analyze the mechanical stress distribution in a pacing lead based on a sequence of paired 2D angiographic images. The 3D positions and geometrical shapes of an implanted pacemaker lead throughout the cardiac cycle were generated using a previously validated 3D modeling technique. Based on the Frenet–Serret formulas, the kinematic property of the lead was derived and characterized. The distribution of curvature and twist angle per unit length in the pacing lead was calculated from a finite difference method, which enabled a rapid and effective computation of the mechanical stress in the pacing lead. The analytical solution of the helix deformation geometry was used to evaluate the accuracy of the proposed numerical method, and an excellent agreement in curvature, twist angle, and stresses was achieved. As demonstrated in the example, the proposed technique can be used to analyze the complex movement and deformation of the implanted pacing lead in vivo. The information can facilitate the future development of pacing leads.

Spin accumulation in triplet Josephson junction

We employ a Hamiltonian method to study the equal-spin pairing triplet Josephson junction with different orbital symmetries of pair potentials. Both the spin/charge supercurrent and possible spin accumulation at the interface of the junction are analyzed by means of the Keldysh Green's function. It is found that a spontaneous angle-resolved spin accumulation can form at the junction's interface when the orbital symmetries of Cooper pairs in two triplet superconductors are different, the physical origin is the combined effect of the different orbital symmetries and different spin states of Cooper pairs due to the misalignment of two d vectors in triplet leads. An abrupt current reversal effect induced by misalignment of d vectors is observed and can survive in a strong interface barrier scattering because the zero-energy state appears at the interface of the junction. These properties of the p-wave Josephson junction may be helpful for identifying the order parameter symmetry.

Effect of signet-ring cell carcinoma histology on bladder cancer outcome

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Background: Signet-ring cell carcinoma (SRCC) of the urinary bladder is a rare entity. Recent case series of the condition showed inconsistent results. We used a population-based data set to compare the cancer specific survival of patients with signet-ring cell carcinoma vs. transitional cell carcinoma (TCC) of the urinary bladder.

Methods: Signet-ring cell carcinoma of the urinary bladder and transitional carcinoma of the urinary bladder were identified in the Surveillance, Epidemiology and End Results program (2001 to 2004). Demographic and pathological characteristics at diagnosis were compared. Differences in cancer specific survival were compared with univariate and multivariate Cox regression analysis.

Results: A total of 103 SRCC cases were present in the database from 2001 to 2004. In that time 14,648 cases TCC cases were diagnosed. SRCC was more common in younger than in older patients (p <0.001); more commonly presented with high grade histology (p <0.001) and advanced stage disease (p <0.001). The 3-year cancer specific survival rate was 67.0% and 33.2% for TCC and SRCC, respectively. On multivariate analysis there was an increased mortality risk in patients with SRCC vs TCC (HR 1.42, 95% CI 1.03–1.97, p <0.001). When only high grade cases of SRCC and TCC were compared, the risk was still worse in SRCC (HR 1.430, 95% CI 1.035–1.976, 0.03). When only local stage of SRCC and TCC were compared, the risk was worse in SRCC (HR 4.294, 95% CI 1.035–17.825, 0.045). Limited to patient who underwent cystectomy only, the difference in cancer specific survival disappeared (HR 1.289, 95% CI 0.771–2.155, 0.33).

Conclusions: Even after adjusting for demographic, pathological and treatment factors, cancer specific survival is significantly worse in patients with SRCC than TCC. Further research into the biology of this rare tumor is required to explain these results.

No significant financial relationships to disclose.

Adjusted indirect comparison of everolimus and sorafenib in sunitinib-refractory mRCC patients using a robust matching technique

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Background: Vascular endothelial growth factor receptor–tyrosine kinase inhibitors (VEGFr-TKIs) sunitinib (SU) and sorafenib (SO) are approved for first- and second-line (after cytokines) use in metastatic renal cell carcinoma (mRCC). Because most patients progress after first-line VEGFr-TKI, the need for an effective second-line treatment is compelling. Although SO is frequently considered after SU failure, no randomized controlled trials have established clinical benefit in this scenario. Results from the RECORD-1 phase III trial suggest that second-line everolimus (EVE) therapy leads to improved overall survival (OS) vs. placebo. No trial data exist comparing treatment outcomes for EVE vs SO in the second-line setting. Thus, the current analysis provides a robust estimate from an indirect comparison examining the OS benefit of EVE and SO as second-line treatment options after SU failure.

Methods: The single-arm SO study was selected as a basis by which to match an EVE SU-refractory subpopulation of the RECORD-1 trial. Patients were limited to those with clear cell histology. An adjusted matching approach was taken in which 1,000 repeated random samples matched to the SO population on risk score distribution were produced. These data were used to generate a distribution of survival outcomes and infer a 95% CI around the mean of all sampled median OS estimates.

Results: After adjusted matching, the estimated median OS benefit, based on SO patients with clear cell histology (n = 45) and 1000 random samples of n = 41 from the 127 SU-refractory EVE patients, was 82 weeks (95% CI: 78, 86) and 32 weeks (95% CI: 22, 64) for EVE and SO, respectively.

Conclusions: These indirect comparison results suggest that SU-refractory mRCC patients treated with EVE may experience significantly improved OS outcomes compared with patients treated with SO.

[Table: see text]

Investigations of mechanical vibrations for beamlines at the Canadian Light Source

Vibration is often a problem causing poor quality of photon beams at synchrotron radiation facilities, since beamlines are quite sensitive to vibrations. Therefore, vibration analysis and control at synchrotron radiation facilities is crucial. This paper presents investigations on mechanical vibrations at four beamlines and endstations at the Canadian Light Source, i.e. the Canadian Macromolecular Crystallography Facility 08ID-1 beamline, the Hard X-ray MicroAnalysis 06ID-1 beamline, the Resonant Elastic and Inelastic Soft X-ray Scattering 10ID-2 beamline, and the Scanning Transmission X-ray Microscope endstation at the Spectromicroscopy 10ID-1 beamline. This study identifies vibration sources and investigates the influence of mechanical vibrations on beamline performance. The results show that vibrations caused by movable mechanical equipment significantly affect the data acquired from beamlines.

Novel mutation in TGA stop-codon of bovine SIX6 gene

As a transcriptional regulatory gene of the SIX family, SIX6 (also known as OPTX2, SIX9), probably affects pituitary development and secretion of hormones, suggesting that this gene is a potential candidate gene for studying association with growth trait in animals. Therefore, this study is first of all focused on detecting sequence variations in a bovine SIX6 gene and on its effects on growth traits in 1087 cattle from five Chinese cattle breeds using DNA sequencing and HhaI-ACRS-PCR methods. Herein, a novel mutation (NC_007308: g 2015T > C) in the TGA stop-codon of a bovine SIX6 gene was found, which leads to an ORF shift and extension of the encoded protein for four amino acids (Arg223-Gln224-Arg225-Val226). The frequency of allele "C" varied from 0.255 (Chinese Holsteins) to 0.614 (Hasake). They all were in the Hardy-Weinberg equilibrium except Jiaxian Red and Hasake cattle. Using amino acid sequence alignment and online prediction software, a new helix in the C-terminal domain of the mutated bovine SIX6 protein was revealed, which possibly affects pituitary development and hormone secretion. So, relationship analysis between this polymorphism and growth traits in the Nanyang breed was carried out based on a proper linear model. Although no statistically significant associations were observed (P > 0.05), the presented work preliminarily demonstrated a novel mutation in the TGA stop-codon which extends the spectrum of genetic variations of the bovine SIX6 gene and might be of interest in terms of its association with other biophysical and biochemical indexes.

Measurement of the isolated prompt photon production cross section in pp collisions at √s=7 TeV

The differential cross section for the inclusive production of isolated prompt photons has been measured as a function of the photon transverse energy E(T)(γ) in pp collisions at √s=7  TeV using data recorded by the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 2.9  pb(-1). Photons are required to have a pseudorapidity |η(γ)|<1.45 and E(T)(γ)>21  GeV, covering the kinematic region 0.006<x(T)<0.086. The measured cross section is found to be in agreement with next-to-leading-order perturbative QCD calculations.

Micro-computerized tomography analysis of alveolar bone loss in ligature- and nicotine-induced experimental periodontitis in rats

BACKGROUND AND OBJECTIVE

Nicotine reportedly is a risk factor for periodontitis, but accurate data regarding nicotine-induced alveolar bone loss is lacking. The aim of this study was to quantitatively assess alveolar bone loss in ligature- and nicotine-induced periodontitis in rats using micro-computerized tomography (micro-CT).

MATERIAL AND METHODS

Thirty-six adult male rats were treated by placing silk ligatures around the cervixes of the right second maxillary molar; the contralateral tooth was untreated. After ligation, the animals were randomly divided into three groups: group A received intraperitoneal injections of saline solution, group B received 0.83 mg of nicotine/kg/d, and group C received 1.67 mg of nicotine/kg/d. Six animals in each group were killed on days 14 and 28 after ligature placement, and then micro-CT examinations were conducted.

RESULTS

  In all groups, bone mineral density (BMD), bone volume fraction (BVF), trabecular number (Tb.N) and trabecular thickness (Tb.Th) values of the ligated sides were significantly lower than those of the unligated sides (p < 0.001), whereas alveolar bone height loss (ABHL) and trabecular separation (Tb.Sp) of the ligated sides were significantly higher than those of the unligated sides (p < 0.001). Compared with the control group, nicotine administration increased the ABHL value and decreased the BMD, BVF and Tb.Th values of both sides in a dose-dependent manner (p < 0.05).

CONCLUSION

  Our results confirmed that ligature could cause significant loss in the trabecula of alveolar bone, and daily administration of nicotine resulted in further bone loss and microstructure deterioration.