Rhythm Control and Cardiovascular or Cerebrovascular Outcomes in Patients with Atrial Fibrillation: A Study of the CODE-AF Registry

BACKGROUND

It is not clear whether the data regarding rhythm control during atrial fibrillation (AF) contained in AF registries is prognostically significant. Thus, this study investigated the relationship between rhythm control and cardiovascular outcomes in patients in contemporary AF registries.

METHODS

This study was conducted using data from 6670 patients with AF receiving oral anticoagulation in the CODE-AF registry. We used propensity overlap weighting to account for differences in baseline characteristics between the rhythm control and rate control groups. The primary outcome was a composite of the rate of death due to cardiovascular causes, stroke, acute coronary syndrome, and heart failure. The secondary outcomes were individual components of the primary outcome.

RESULTS

In the CODE-AF registry, 5407 (81.1%) patients were enrolled three months after AF diagnosis. During a median follow-up period of 973 days (interquartile range: 755-1089 days), a primary outcome event occurred in 72 patients in the rhythm control group (1.4 events per 100 person-years) and in 211 patients in the rate control group (1.8 events per 100 person-years). However, after overlap weighting, the incidence rates were 1.4 and 1.5 events per 100 person-years, respectively. No significant difference was found in either the primary outcome (weighted HR: 0.87; 95% CI: 0.66-1.17; p = 0.363) or secondary outcomes between the rhythm control and rate control groups.

CONCLUSION

In a prospective AF registry in which most of the population was enrolled at least three months after AF diagnosis, no difference in the risk of cardiovascular or cerebrovascular outcomes was found between the rhythm control and rate control groups, suggesting the early rhythm control should be considered to improve the outcome of patients.

Epigenetic alterations of the BDNF gene in combat-related post-traumatic stress disorder

OBJECTIVE

Brain-derived neurotrophic factor (BDNF) plays a crucial role in modulating resilience and vulnerability to stress. The aim of this study was to investigate whether epigenetic regulation of the BDNF gene is a biomarker of post-traumatic stress disorder (PTSD) development among veterans exposed to combat in the Vietnam War.

METHODS

Using the Clinician-Administered PTSD Scale, combat veterans were grouped into those with (n = 126) and without (n = 122) PTSD. DNA methylation levels at four CpG sites within the BDNF promoter I region were quantified in the peripheral blood using pyrosequencing. The effects of BDNF DNA methylation levels and clinical variables on the diagnosis of PTSD were tested using binary logistic regression analysis.

RESULTS

Subjects with PTSD showed a higher DNA methylation of four CpG sites at the BDNF promoter compared with those without PTSD. High methylation levels at the BDNF promoter CpG site, high combat exposure, and alcohol problems were significantly associated with PTSD diagnosis.

CONCLUSIONS

This study demonstrated an association between higher DNA methylation of the BDNF promoter and PTSD diagnosis in combat-exposed individuals. Our findings suggest that altered BDNF methylation may be a valuable biomarker of PTSD after trauma exposure.

Histochemical study on neurodegeneration in the olfactory bulb after transient forebrain ischaemia in the Mongolian gerbil

In the present study, we investigated the ischaemia-related neurodegeneration in the main and accessory olfactory bulb (AOB) after 5 min transient forebrain ischaemia in the Mongolian gerbil using the acid fuchsin staining method. Between 5 and 15 days after ischaemia, acid fuchsin positive cells markedly increased in the external plexiform layer (EPL), mitral cell layer (ML) and glomerular layer (GL) of the main olfactory bulb (MOB), and in the mixed cell layer (MCL) and GL of the AOB. By 30 days after ischaemia reperfusion, acid fuchsin positive neurons were shrunken and showed low acidophilia in somata. Many necrotic vacuoles were found in the EPL and GL of the MOB 30 days after ischaemia. At this time, necrotic vacuoles were very few in the AOB. Therefore, our results suggest that the GL and EPL of the MOB are vulnerable to ischaemic damage at a later time after ischaemic insult, and that the AOB is more resistant to ischaemic damage as compared with the MOB.

Changes of Calbindin D-28k Immunoreactivity in the Hippocampus after Adrenalectomy in the Seizure Sensitive Gerbil

Calbindin D-28k (CB), a calcium-binding protein, containing neurons in the hippocampus plays an important role in hippocampal excitability in epilepsy. In the present study, we investigated changes of CB immunoreactivity after adrenalectomy (ADX) in the hippocampus and dentate gyrus of the seizure sensitive gerbil, which is susceptible to seizure to identify roles of CB in epileptogenesis. The changes of the CB immunoreactivity after ADX were significant in the hippocampal CA1 region. By 24 h after ADX, CB-immunoreactive CA1 pyramidal cells and CB immunoreactivity increased. At this time, well-stained dendrites projected to the stratum radiatum. Thereafter, the CB immunoreactivity decreased time dependently by 96 h after ADX. In the dentate gyrus, the changes of CB-immunoreactive neurons were mainly observed in the granule cell layer. The number and immunoreactivity of CB-immunoreactive neurons was high at 24 h after ADX, thereafter, those decreased by 96 h after ADX. These results suggest that glucocorticoid has an important role in modulating the seizure activity and CB serves an inhibitory function, which regulates the seizure activity and output signals from the hippocampus.

Chronological Alterations of P2X3 Receptor Expression in the Trigeminal Ganglion after Ischaemic Insult in the Mongolian Gerbil

P2X receptors play a role in the transduction of sensory signals like pain. Few studies have been undertaken on altered P2X(3) receptor (P2X3) expression in sensory neurones after peripheral nerve injury. In the present study, we investigated chronological alterations in P2X3 immunoreactivity and its protein content in the trigeminal ganglion after ischaemic insult in the Mongolian gerbil. In the sham-operated group, P2X3-immunoreactive neurones were found abundantly in small- and medium-sized neurones. From 1 day after ischaemic insult, the number of P2X3-immunoreactive neurones decreased significantly. At 5 days after ischaemic insult, P2X3 immunoreactivity was observed in few neurones, but its immunoreactivity was weak. However, the number of cresyl violet-positive neurones was unchanged throughout this period in all groups. These results suggest that transient trigeminal ganglion ischaemia may provoke a decrease of P2X3 expression and its protein content, and that this down-regulation of P2X3 may be related to the altered pain and thermal sensation without being associated with a transient ischaemic insult.

Inhibition of the EGF-induced activation of phospholipase C-gamma1 by a single chain antibody fragment

Phospholipase C-gamma1(PLC-gamma1) is known to play an essential role in various cellular responses, such as proliferation and tumorigenesis, and PLC-gamma1-specific inhibitors are commonly employed to investigate the mechanism of the PLC-gamma1-mediated signaling pathway. In this study, we developed a single chain antibody fragment (scFv) as a blocker for PLC-gamma1 mediated signaling. scFv, designated F7-scFv, specifically bound to PLC-gamma1 with high affinity (K(d)=1.9x10(-8) M) in vitro. F7-scFv also bound to PLC-gamma1 in vivo and altered the distribution pattern of PLC-gamma1 from the cytoplasm to the intracellular aggregates, where F7-scFv was localized. Moreover, F7-scFv interrupted the EGF-induced translocation of PLC-gamma1 from the cytosol to the membrane ruffle and attenuated EGF-induced inositol phosphates generation and intracellular calcium mobilization. These results indicate that F7-scFv blocks EGF-induced PLC-gamma1 activation by causing sequestering of PLC-gamma1 into intracellular aggregates, and may therefore be useful in studies of the PLC-gamma1-mediated signaling pathway.

Neuregulin induces the expression of mesodermal genes in the ectoderm of Xenopus laevis

The primary patterning event in early vertebrate development is the formation of mesoderm and subsequent induction of the neural tube by the mesoderm. Some of the transforming growth factor (TGF)-beta family (Activin, Vg1) and the fibroblast growth factor (FGF) family molecules have been implicated for their roles in mesoderm induction. Here we show first the evidence that neuregulin, an epidermal growth factor (EGF)-like growth factor known for its role in neural and muscle differentiation, participates in mesoderm induction. Neuregulin could induce the ectopic expression of mesoderm specific gene Xbra in animal cap explants reared to the midgastrula stage, when animal caps dissected from late blastula were cultured with Neuregulin at a low concentration (10 ng/ml). In situ hybridization study showed that alpha-cardiac actin was expressed in animal caps that were treated with Neuregulin overnight. Skeletal and cardiac muscle specific genes such as MyoD family genes (myoD, MRF4, myf5) and SL1 as well as NCAM, a pan neural marker, were also ectopically expressed by treatment with Neuregulin. However, the expression of NCAM is presumed to be a secondary result of the initial mesoderm induction by Neuregulin. The temporal expression pattern of neuregulin during the early developmental stages was analyzed by RT-PCR in order to determine if neuregulin is expressed at the time of mesoderm induction. It has been found that the neuregulin transcript was already detected from the 16-cell stage (stage 5) and continued to be expressed till the tailbud stage (stage 25), the latest embryonic stage analyzed in this study. Considering that the mesoderm is induced at early blastula before the start of zygotic transcription, maternal neuregulin is expressed at the right time to participate in mesoderm induction. These data strongly suggest that neuregulin plays an important role in mesoderm induction.

Epidemiological and clinical features of Behçet's disease in Korea

Behçet's disease occurs with a high prevalence in the Far East including Korea. In this report we inspected 1,155 patients with Behçet's disease and collected information concerning the clinical and epidemiologic features of Behçet's disease in Korea. In summary, patients in their 30s were the most common, with the most common age of onset in the 20s; the sex ratio was 0.63:1 with female predominance; according to revised Shimizu's classification, the order of frequency of the different types was incomplete (38.2%), suspected (25.4%), possible (20.3%) and complete (16.1%); oral ulcers were the most frequent major symptom (97.5%) and the most common initial symptom (78.5%); erythema nodosum-like lesion (55.3%) was the most common type of skin lesion; a seasonal aggravation of the disease was observed in 21.3% of patients; and the most common type of childhood onset Behçet's disease was suspected type.

Evaluation of the strain energy release rate for the fracture of titanium-porcelain interfacial bonding

An attempt has been made to measure the critical strain energy release rate or interfacial toughness between an oxide coating and metal layer in the present study. Twelve pure titanium cast plates veneered with transparent incisal porcelain were subjected to four-point bending after introducing a precrack through a controlled notch on the ceramic veneer. Cycles of loading and unloading at crosshead speed of 0.1 mm min-1 were repeated and extension of the crack along the interfacial oxide layer was observed through the transparent porcelain. Parallelled extension with the initial notch at each loading was observed and multiple loading was possible until the crack reached the inner loading points. Fracture resistance was calculated by dividing the energy value determined from a force-displacement curve by the corresponding fracture area. A theoretical calculation of the fracture resistance using a formula developed by Charalambides et al. (J. Appl. Mech., 1989, 56, 77-82) was also estimated. The result from the two methods agreed well (R2 = 0.75) but the theoretical calculation (16.06 +/- 4.53J m2) gave lower average value than the other value (18.29 +/- 4.23J m2), (p < 0.05). These preliminary results indicate that this novel technique is a suitable means for quantifying interfacial toughness of porcelain-metallic bonding.

Enhancement of a titanium denture frame model: mold temperature and spruing factors

This study evaluated the sensitivity of an experimental model to mold temperature using a two-chamber casting machine and its recommended investment (Exp. 1), and the effect of sprue diameter and length using a one-chamber casting machine and its recommended investment (Exp. 2). Experimental patterns were cast from commercially pure titanium and percentage casting success obtained. Mold temperatures of 620, 350 and less than 100 degrees C, and sprues, 4 or 6 mm diameter and 5, 20 or 26 mm long, were used. The effect on casting success of a "non-system" investment was also evaluated in both experiments. The experimental model did not discriminate the two lower mold temperatures (Exp. 1). Casting success was significantly lower with a 4 mm sprue diameter but was not affected by sprue length (Exp. 2). The results suggest the importance of the combination of casting machine, investment type and mold dimension.

In search of a suitable denture marker

The ID-Band (SDI AB, Sweden) has become the standard, internationally and FDI accepted denture marking system. In Australia however the strip is not easily obtainable and is expensive. Two other materials have been trialled as possible alternatives: (1) Titanium foil (9 microns) and (2) Ho Band (matrix) (3 microns) (Lorvic Corp, USA). All three bands were tested for tensile strength and elongation at temperatures: RT, 700 degrees and 900 degrees C. As the ID- and Ho Bands are both 18-8 stainless steel their performance was similar. The 18-8 was stronger, had a higher percentage break point and a higher elongation. The latter meant that it was softer and could be more easily inscribed and was therefore more suitable for denture marking. T1 is becoming increasingly used in dentistry but in spite of its abundance it is not likely to replace stainless steel for denture marking at present. On the other hand the Ho Band is cheaper, more readily available and it could replace ID-Band for use in Australia. An alternative paper based marking system is also presented together with the rationale for its use.

[A photoelastic study of the stress distributions in the surrounding tissues of the abutments of a fixed partial denture with secondary abutments]

The purpose of this study was to evaluate the stress distributions of fixed partial dentures with secondary abutments. In the case where the lower first premolar and the second premolar were missing, four 2-dimensional photoelastic models with the canine and the first molar as primary abutments with secondary abutments were prepared as follows; Model I: primary abutments only. Model II: primary abutments with the lateral incisor as the secondary abutment. Model III: primary abutments with the second molar as the secondary abutment. Model IV: primary abutments with the lateral incisor and the second molar as secondary abutments. Two-dimensional photoelastic stress analysis was used with the stress areas recorded photographically. A vertical load was applied to the pontic in each case. After the stress patterns in surrounding tissues of the abutments were observed and recorded, the conclusions were as follows: 1. In model I, applied force was distributed to the long axis of the abutments. 2. In model II, III, IV, all the secondary abutments showed compressive stresses. No tensile stresses were developed. 3. The mesial aspect of the lateral incisor and the distal aspect of the second molar as the secondary abutment showed no compressive stresses.

[A photoelastic study of the stress distribution in the surrounding tissues of the abutments of a fixed partial denture with tilted molar abutments]

The purpose of this study was to evaluate the stress distributions to the abutments of a fixed partial denture with tilted molar abutments. In cases of the lower 1st molar being missing four 2-dimensional photoelastic models with 3- unit fixed partial dentures of which the 2nd molars were tilted 0 degrees, 10 degrees, 20 degrees and 30 degrees toward the 2nd premolar were made. A vertical load of 50 lbs was applied to the 1st and 2nd molar in each case. Two-dimensional photoelastic stress analysis was used, and the stress areas were recorded photographically. The results were as follows; 1. When the vertical load was applied to pontic and 2nd molar on the central fossae, the magnitude of stress distribution of the surrounding tissues of the root of the 2nd premolar was increased incrementally with increasing inclination. 2. Under two loading conditions, the stress distributions were directed to the long axis of the abutments. 3. In this experiment, no stress distributions were observed on the mesial area of the mesial root of the second molar.