Simple versus complex stenting strategy for coronary artery bifurcation lesions in the drug-eluting stent era: a meta-analysis of randomised trials

BACKGROUND

Coronary bifurcation lesions remain a challenge for interventional cardiologists and the optimal stenting strategy has not been established in the current drug-eluting stent (DES) era. This study compared two strategies for DES treatment of coronary bifurcation lesions: a simple stenting approach (stenting only the main vessel (MV) and provisional stenting of the side branch (SB) only when bailout of the SB is necessary) versus a complex stenting approach (routinely stenting not only MV but also SB).

METHODS

Data sources included PubMed and conference proceedings. Prespecified criteria were met by five randomised studies comparing simple stenting strategy versus complex stenting strategy in 1553 patients with coronary bifurcation lesions. Studies reported the clinical and angiographic outcomes of efficacy and safety during a minimum of 6 months.

RESULTS

The risks of follow-up myocardial infarction (MI) (relative ratio (RR) 0.54, 95% confidence interval (CI) 0.37 to 0.78, p = 0.001) and early (in-hospital or 30-day) MI (RR 0.52, 95% CI 0.35 to 0.78, p = 0.002) were markedly lower in patients treated with the simple strategy compared to the complex strategy. There were no significant differences between the two different strategies with respect to the rates of cardiac death (RR 0.68, 95% CI 0.21 to 2.25, p = 0.53), target lesion revascularisation (TLR) (RR 0.93, 95% CI 0.62 to 1.41, p = 0.74) or definite stent thrombosis (ST) (RR 0.50, 95% CI 0.19 to 1.32, p = 0.16). The restenosis risk of MV and SB did not differ between the simple strategy group and the complex strategy group (RR 1.15, 95% CI 0.66 to 2.00, p = 0.63 and RR 1.12, 95% CI 0.80 to 1.57, p = 0.50, respectively).

CONCLUSIONS

Compared to the complex strategy for DES treatment of coronary bifurcation lesions, the simple strategy was associated with a lower risk of early MI and a similar rate of angiographic restenosis. Since the complex strategy could not improve the clinical or angiographic outcome, the simple strategy can be recommended as a preferred bifurcation stenting technique in the DES era.

A simple and evolutional approach proven to recanalise the nasolacrimal duct obstruction

Aim:

To evaluate a new approach of recanalisation of nasolacrimal duct obstruction (RC-NLDO) in the treatment of the nasolacrimal duct obstruction (NLDO) and chronic dacryocystitis.

Methods:

583 patients with 641 eyes suffering from NLDO and chronic dacryocystitis were enrolled in this study. The RC-NLDO was performed in 506 eyes, with 135 eyes undergoing external dacryocystorhinostomy (EX-DCR) as controls. Patient follow-up for 54 months was evaluated by symptoms, dye disappearance test, lacrimal irrigation and digital subtraction dacryocystogram. The RC-NLDO was also performed in 12 rhesus monkeys for histopathological examination.

Results:

The clinical success rates were 93.1% in 506 cases of RC-NLDO and 91.11% in 135 cases of EX-DCR. The success rates for second surgery were achieved in 85.19% on RC-NLDO and 40.0% on EX-DCR. No major intra- or postoperative complications were observed in the RC-NLDO group. The mean operative duration was 12.5 min for RC-NLDO and 40.3 min for EX-DCR (p<0.001). A pathological study in rhesus monkeys demonstrated that the RC-NLDO wounded epithelium in nasolacrimal duct healed completely within 1 month without granulation tissue formation.

Conclusion:

The findings demonstrate that the RC-NLDO is a simple and effective approach proven to recanalise the obstructed nasolacrimal duct with a comparable success rate to EX-DCR.

Epidemiology and clinical management of cardiomyopathies and heart failure in China

Heart failure (HF), a syndrome of clinical symptoms and signs, is the most serious and the final outcome of all heart diseases and as in other parts of the world it is a common cause for admission to hospital in the Chinese population. In this review the epidemiological data on cardiomyopathies, HF and current treatment for chronic HF among people living in China are summarised.

Expression and regulated nuclear transport of transducers of regulated CREB 1 in retinal ganglion cells

Calcium- and cAMP-dependent activation of CREB and transcription of cAMP-responsive element (CRE)-target genes play critical roles in various physiological and pathological conditions. TORCs (transducers of regulated CREB) represent a new family of conserved CREB coactivators that function as intracellular calcium- and cAMP-sensitive coincidence detectors, controlling the kinetics of CRE-mediated responses and long-term potentiation of synaptic transmission. Here we examined the expression and activity-dependent translocation of TORCs in adult retinal ganglion cells (RGCs), the primary target of acute retinal ischemic injury as well as chronic retinal degenerative diseases. We found that both mRNAs of TORC1 and TORC2, but not TORC3, were enriched in adult rat retina. Comparing with TORC2, TORC1 protein was highly and selectively expressed in RGCs. At resting condition, TORC1 protein was localized in the cytoplasm but not nucleus of RGCs. Activation of N-methyl-D-aspartate (NMDA) receptors by intravitreous injection of NMDA or increase of cAMP signaling by administration of forskolin triggered nuclear accumulation of TORC1. Furthermore, transient retinal ischemic injury resulted in peri-nuclear and nuclear accumulation of TORC1 as well as transcription of BDNF in RGCs. Our results demonstrate that TORC1 is enriched in RGCs and its subcellular location could be regulated by Ca(2+) and cAMP, suggesting that manipulation of TORC1 activity may promote survival of RGCs in some optic disease conditions.

Administration of intracoronary bone marrow mononuclear cells on chronic myocardial infarction improves diastolic function

BACKGROUND

Regeneration of the myocardium and improved ventricular function have been demonstrated in patients with acute myocardial infarction (MI) treated by intracoronary delivery of autologous bone marrow mononuclear cells (BMC) a few days after successful myocardial reperfusion by percutaneous coronary intervention (PCI); however, the effects of intracoronary cell infusion in chronic MI patients are still unknown.

AIMS

To investigate whether intracoronary infusion of BMC into the infarct-related artery in patients with healed MI could lead to improvement in left ventricular (LV) function.

METHODS

Among 47 patients with stable ischaemic heart disease due to a previous MI (13 (SD 8) months previously), 24 were randomised to intracoronary infusion of BMC (BMC group) and 23 to a saline infusion (control group) into the target vessel after successful PCI within 12 hours after chest pain occurred. LV systolic and diastolic function, infarct size and myocardial perfusion defect were assessed with the use of echocardiography, magnetic resonance imaging (MRI) or (201)Tl single-photon-emission computed tomography (SPECT) at baseline and repeated at the 6-month follow-up examination.

RESULTS

BMC treatment did not result in a significant increase in LV ejection fraction in any of the groups by any of the methods used, and the apparent tendency of an improvement was not statistically different between the two groups. The two groups also did not differ significantly in changes of LV end-diastolic and systolic volume, infarct size or myocardial perfusion. However, there was an overall effect of BMC transfer compared with the control group with respect to early/late (E/A) (p<0.001), early diastolic velocity/late diastolic (Aa) velocity (Ea/Aa) ratio (p = 0.002) and isovolumetric relaxation time (p = 0.038) after 6 months, as evaluated by tissue Doppler echocardiography. We noted no complications associated with BMS transfer.

CONCLUSION

Intracoronary transfer of autologous BMC in patients with healed MI did not lead to significant improvement of cardiac systolic function, infarct size or myocardial perfusion, but did lead to improvement in diastolic function.

Characterization of some morphological parameters of orbicularis oculi motor neurons in the monkey

The primate facial nucleus is a prominent brainstem structure that is composed of cell bodies giving rise to axons forming the facial nerve. It is musculotopically organized, but we know little about the morphological features of its motor neurons. Using the Lucifer Yellow intracellular filling method, we examined 11 morphological parameters of motor neurons innervating the monkey orbicularis oculi (OO) muscle, which plays an important role in eyelid closure and voluntary and emotional facial expressions. All somata were multipolar and remained confined to the intermediate subnucleus, as did the majority of its aspiny dendritic branches. We found a mean maximal cell diameter of 54 microm in the transverse dimension, cell diameter of 60 microm in the rostrocaudal dimension, somal surface area of 17,500 microm(2) and somal volume of 55,643 microm(3). Eight neurons were used in the analysis of dendritic parameters based upon complete filling of the distal segments of the dendritic tree. We found a mean number of 16 dendritic segments, an average dendritic length of 1036 microm, diameter of 7 microm, surface area of 12,757 microm(2) and total volume of 16,923 microm(3). Quantitative analysis of the dendritic branch segments demonstrated that the average number, diameter and volume gradually diminished from proximal to distal segments. A Sholl analysis revealed that the highest number of dendritic intersections occurred 60 microm distal to the somal center with a gradual reduction of intersections occurring distally. These observations advance our understanding of the morphological organization of the primate facial nucleus and provide structural features for comparative studies, interpreting afferent influence on OO function and for designing studies pinpointing structural alterations in OO motor neurons that may accompany disorders affecting facial movement.

A new strategy to replace the natural vitreous by a novel capsular artificial vitreous body with pressure-control valve

PURPOSE

The current vitreous substitutes such as silicone oil, heavy silicone oil, and polymeric gels that are directly injected into vitreous cavity frequently cause severe intraocular complications. There is a very urgent need to find a more suitable artificial vitreous substitute for pars plana vitrectomy (PPV) surgery.

METHODS

We have devised a novel capsular artificial vitreous using tailor-made silicone rubber elastomer. The novel device was implanted into the vitreous cavity of rabbit after PPV and the eye was examined by ophthalmoscopy, fundus photography, and tonometry during an 8-week treatment period. B-scan ultrasonography, electroretinogram (ERG), and histological studies by light microscopy were also performed at the end of 8 weeks.

RESULTS

The novel artificial vitreous body consists of a thin vitreous-like capsule with a silicone tube-valve system. The capsule can be folded and implanted into vitreous cavity through 1.5 mm incision on sclera. Physiological balanced solution (PBS) was then injected into the capsule and inflated to support retina and control intraocular pressure (IOP) through the tube-valve system subsequently fixed under the conjunctiva. Experiments using rabbits showed that the novel vitreous body could effectively support the retina and apparently induced no significant pathological changes in the eye over 8 weeks.

CONCLUSION

This approach may provide a new research strategy in the vitreous replacement technology. The novel artificial vitreous body device can effectively support retina, control IOP, and has good biocompatibility. It may be a good alternative to injecting artificial vitreous although its tamponade properties and usefulness still have to be proven in complex vitreoretinal diseases.

Efficacy of emergent transcatheter transplantation of stem cells for treatment of acute myocardial infarction (TCT-STAMI)

OBJECTIVE

To study whether emergent intracoronary autologous bone marrow cell transplantation (BMT) is applicable for the treatment of acute myocardial infarction (AMI).

METHODS

20 patients admitted within 24 h after the onset of a first AMI were randomly allocated to receive intracoronary autologous BMT (n = 10) or bone marrow supernatant (controls, n = 10) immediately after primary percutaneous coronary intervention. Left ventricular ejection fraction (LVEF), left ventricular end diastolic internal diameter (LVDd) and myocardial perfusion defect scores were examined respectively by echocardiography and single-photon emission computed tomography at one week and six months after AMI.

RESULTS

From one week to six months after AMI, LVEF was enhanced from mean 53.8 (SD 9.2)% to 58.6 (9.9)% (p < 0.05) in the BMT group but was unchanged in the control group (58.2 (7.5)% v 56.3 (3.5)%, p > 0.05); LVDd remained unchanged (52.5 (2.8) v 52.1 (3.2) mm, p > 0.05) in the BMT group but was significantly enlarged in the control group (50.4 (6.0) v 55.2 (7.1) mm, p < 0.05). Additionally, myocardial perfusion defect scores decreased from 21 (11) to 13 (10) (p < 0.01) in the BMT group but were unchanged in the control group (20 (14) v 17 (15), p > 0.05).

CONCLUSION

Emergent intracoronary transplantation of bone marrow mononuclear cells after AMI is practicable, and it improved cardiac function, prevented myocardial remodelling and increased myocardial perfusion at six months' follow up.

Property variations in the prism and the organic sheath within enamel by nanoindentation

Atomic force microscopy (AFM) combined with nanoindentation technique was used to definitely, site-specifically, test the nanomechanical properties, including nanohardness and elastic modulus, of the isolated domains within single enamel, the prisms and the surrounding sheaths, of mature human maxillary third molars. In this way, it is for the first time that evident differences of nanomechanical properties were revealed between these domains. The nanohardness and elastic modulus of the sheaths were about 73.6% and 52.7% lower than those of the prisms, respectively. Measuring the residual impressions with AFM supported the similar conclusion. The variations of mechanical properties in these domains are considered to be mainly relative to their different component and fibrils arrangement.

Hierarchical structural comparisons of bones from wild-type and liliput(dtc232) gene-mutated Zebrafish

The alterations of hierarchical structures of bone by gene mutation in the zebrafish, which is associated with abnormal bone mineralization and bone disease, were reported for the first time in this paper. Bone samples from the liliput(dtc232) (lil) mutants as well as normal controls were studied by polarized light microscope, scanning electron microscope (SEM), transmission electron microscope (TEM), and atomic force microscope (AFM). Light microscopy examinations reveal that the lil bone has asymmetric mineralization and much thinner bone wall. The SEM studies show a lot of microcracks in lil bone wall. And the plywood-like structure of the normal bone does not exist in the lil bone, which is confirmed by the measurements of polarized light microscope. Furthermore, the TEM investigations display the collagen fibrils with two typical diameters. For the thinner collagen fibrils, the diameter of lil bone is about twice larger than that of the wild-type bone. And for the thicker one, there is a small increase in diameter after mutation and the band periodicity of the lil bone is similar with that of wild-type bone, which is consistent with the result of AFM. The morphologies of the minerals revealed that the mutated mineral was in bigger size and the shape was irregular but not plate-shaped.

Variation of nanomechanical properties of bone by gene mutation in the zebrafish

Significant variations of nanomechanical properties and fracture morphology between gene-mutated liliput(dtc232) (lil/lil) zebrafish skeletal bone and wild-type bone have been observed. Nanoindentation measurement disclosed that lil/lil bone has 36% lower nanohardness and 32% lower elastic modulus. The standard deviations of hardness and elastic modulus of lil/lil bone were both much higher than those of wild-type bone. SEM morphology of fracture surfaces further revealed that in bones after gene mutation, formative microcracks make the performance reduction and the increasing of brittleness. What is more, the plywood-like structure of the normal bone does not exist in the lil/lil bone.

Functional relationship between subfornical organ cholinergic stimulation and cellular activation in the hypothalamus and AV3V region

The subfornical organ (SFO) has been suggested to be important for water intake and secretion of vasopressin (AVP). However, the role of the SFO cholinergic mechanism in the control of body fluid regulation is not clear. This study determined the effects of local cholinergic stimulation in the SFO produced by administration of physostigmine on drinking and cellular excitation in the anterior third ventricle (AV3V) region and in the supraoptic and paraventricular nuclei (SON and PVN). The results showed that injection of physostigmine into the SFO induced water intake and c-fos expression in the AV3V area as well as in the AVP containing neurons in the hypothalamus. Pretreatment of the SFO with mecamylamine, a nicotinic receptor antagonist, had no effect on physostigmine induced behavioral and c-fos responses. The muscarinic receptor blocker atropine, however, abolished both drinking and cellular activation after injection of physostigmine into the SFO. Immunostaining experiments demonstrated positive acetyltransferase (ChAT) in the SFO. Intensive ChAT immunoreactivity was located in the cholinergic fibers in the SFO. Together, the results indicate that SFO cholinergic mechanisms are important in co-operation with the AV3V and hypothalamic neurons in the control of thirst and AVP-mediated body fluid homeostasis.

[Amplifying variable region gene of light chain of monoclonal antibody against human retinoblastoma by PCR]

OBJECTIVE

To acquire the variable region gene of light chain of monoclonal antibody against human retinoblastoma.

METHODS

Total RNA were extracted from hybridoma cells secreting specific monoclonal antibody(McAb) against human retinoblastoma(RB), then transcripted reversely into cDNA with random primers. The variable region of the light chain(VL) gene fragments were ampliflied using polymerase chain reaction(PCR) method. Agrose gel electrophoresis was confirmed.

RESULTS

1.5% agrose gel electrophoresis indicated that VL gene was about 340 base pairs.

CONCLUSION

The light chain variable region gene of the McAb against human RB was amplified successfully, which lays a good basis for construction of a recombinant antibody.

[The ocular hypotensive effect and safety of 0.2% brimonidine]

PURPOSE

To study the ocular hypotensive efficacy and safety of 0.2% Brimonidine when used in chinese people.

METHODS

Using randominzed parallel group control study, 0.2% Brimonidine twice a day or 1% Carteolol twice a day was applied in patients with primary open angle glaucoma or ocular hypertension for three months.

RESULTS

The results showed that 0.2% Brimonidine and 1% Carteolol both have good ocular hypotensive efficacy. There was no significant difference between them. 0.2% Brimonidine did not produce significant changes in pupil size and heart rate. Change in blood pressure was not clinically significant. Six patients with 0.2% Brimonidine had drowsiness. Two patients had dry mouth. One patient had ocular burning.

CONCLUSION

Our results suggested that 0.2% Brimonidine would be a stable and effective antiglaucoma medicine with good tolerance. Thus, 0.2% Brimonidine should be the main choice of medical therapy for primary open angle glaucoma and ocular hepertension.

Increased heterogeneity of coronary perfusion in patients with early coronary atherosclerosis

BACKGROUND

In patients with typical angina but angiographically normal coronary arteries, abnormal vasomotor function is assumed to be a major underlying cause. However, data on this issue are conflicting, and recent studies suggest that fluid dynamic abnormalities exist in these patients. The aim of the study was to evaluate whether early stages of atherosclerosis are characterized by alterations of baseline coronary hemodynamics and endothelium-independent vasomotion. Besides established intracoronary Doppler parameters, heterogeneity of perfusion was assessed and related to early signs of atherosclerosis as determined by electron-beam computed tomography (EBCT).

METHODS

In 59 patients with typical angina and angiographically normal or near-normal coronary arteries, intracoronary Doppler measurements were performed in all 3 major coronary arteries. Baseline average peak velocity (bAPV) and hyperemic average peak velocity (hAPV) in response to intracoronary injection of adenosine were measured, and coronary flow velocity reserve (CFVR) was calculated. Heterogeneity was assessed as variability of bAPV, hAPV, and CFVR and was calculated as (STD/MEAN). 100. Doppler data were analyzed according to tertiles of the EBCT-derived Agatston calcium score (ie, score 0-1 [lowest tertile], 2-28 [medium tertile], and >28 [highest tertile]).

RESULTS

The mean EBCT-derived Agatston calcium score was 49 +/- 107. No coronary calcium was observed in 17 (29%) patients. The mean values of bAPV, hAPV, and CFVR were not different between the calcium score tertiles. However, patients in the highest tertile had a significantly increased variability index of bAPV (29.6% +/- 11.6%) compared with patients in the lowest tertile (13.4% +/- 7.3%, P <.0001). Variability of CFVR was also increased in these patients (15.5% +/- 11.7% vs 10.5% +/- 4.0%, P =.03).

CONCLUSION

These results indicate that early stages of atherosclerosis are characterized by microvascular abnormalities that do not uniformly affect the myocardium but are heterogeneous. The high variability of baseline coronary flow velocity with increasing coronary calcium suggests that in patients with early stages of atherosclerosis fluid dynamic effects may play a crucial role even in the absence of angiographically appreciable epicardial stenoses.

[Design of multi-channel EEG collection system for stereoscopic VEP and study of the VEP evoked by binocular disparity]

A multi-channel EEG collection system has been constructed for visual evoked potentials (VEP) studies, using IBM compatible PC and clinical EEG amplifier. The collection system not only is suitable for investigative and clinical use, but also works perfectly in the EEG collection and signal processing of stereoscopic VEP. The characters of the depth related VEP evoked by binocular disparity were identified after analysing and comparing the VEP superposition results. The partial results of the VEP extraction are in accord with the previous studies. The system serves as a helpful tool in studies of stereoscopic cognition and brain function.

The preliminary experimental study of induced differentiation of embryonic stem cells into corneal epithelial cells

PURPOSE

To study preliminarily induced differentiation of embryonic stem cells into corneal epithelial cells in vitro.

METHODS

Murine embryonic stem cells were co-cultured with Rabbit limbal corneal epithelial cells in Transwell system to induce differentiation. Mophological and immunohistochemical examination were implemented.

RESULTS

The induced cells from embryonic stem cells have an epithelial appearance. The cells formed a network and were confluent into film gradually after being co-cultured with rabbit limbal corneal epithelial cells for 24-96 hours. The cells ranged mosaic structure and localized together with clear rim. Most of the cells showed polygonal appearance. Transmission electron microscope showed lots of microvilli on the surface of induced cells and tight junctions between them. These epithelial-like cells expressed the corneal epithelial cell specific marker cytokeratin3/cytokeratin12.

CONCLUSION

The potential mechanism of the differentiation of murine embryonic stem cells into corneal epithelial cells induced by limbal corneal epithelial cell-derived inducing activity is to be further verified.

Construction of the enhanced yellow fluorescent protein expression vector carrying IFN-gamma gene

PURPOSE

To construct the enhanced yellow fluorescent protein (EYFP) vector carrying interferon-gamma gene (ifn-gamma) in order to provide an ideal reporter in the expression of ifn-gamma and location of protein in vitro and in vivo.

METHOD

According to the nucleotide sequence of ifn-gamma gene, a pair of oligonucleotides was designed as primer whose two end contained nucleotide sequence of EcoR V and Not I restriction endonuclease respectively. The gene encoding for inf-gamma was amplified using PCR technqiue. After the PCR product was retrieved and purified, it was digested with EcoR V and Not I restriction endonuclease, and then cloned into the plasmid pIRES-EYFP. The recombinant plasmid pIRES-EYFPIFN-gamma was identified by restriction endonuclease enzyme analysis and DNA sequence analysis.

RESULTS

The ifn-gamma was successfully amplified and verified by partial DNA sequence analysis. The recombinant plasmid was correctly screened.

CONCLUSION

The EYFP expression vector carrying ifn-gamma gene was successfully established. This research work has formed a base for monitoring the ifn-gamma gene expression and protein position in living cells.

Identified circadian rhythm genes of ciliary epithelium with differential display

PURPOSE

To identify differential genes expressed in the rabbit ciliary epithelium during the circadian cycle of aqueous flow.

METHODS

Total RNA from ciliary epithelium of rabbits at 8 AM (light on 1 hour) and 8 PM (light off 1 hour) were compared by differential display reverse transcription-polymerase chain reaction (DD RT-PCR), using 6% denaturing polyacrylamide electrophoresis, choose differential display bands, cut and reamplify with the same primer, clone and sequence. Search the database of Genbank, prolong them with 5' RACE and 3' RACE technique then clone, sequence and search database of Genbank.

RESULTS

93 Significant differences gene expression were detected between light on and light off in the rabbit ciliary epithelium.

CONCLUSION

Differential display is a powerful tool to screen differentially expressed genes in circadian rhythm of ciliary epithelium.

[Preliminary clinical study on the management of angle-closure glaucoma by phacoemulsification with foldable posterior chamber intraocular lens implantation]

OBJECTIVE

To investigate the clinical results of phacoemulsification with foldable posterior chamber intraocular lens (PC-IOL) implantation in the management of angle-closure glaucoma with cataract.

METHODS

Phacoemulsification with PC-IOL implantation performed on 47 eyes (42 cases) with angle-closure glaucoma and cataract was retrospectively studied, including 26 eyes with primary acute angle-closure glaucoma, 12 eyes with primary chronic angle-closure glaucoma, 5 eyes with secondary acute angle-closure glaucoma and 4 eyes with secondary chronic angle-closure glaucoma.

RESULTS

After a mean postoperative follow-up of (18.40 +/- 9.51) months, the intraocular pressure was reduced from a preoperative mean of (25.47 +/- 18.43) mm Hg to a postoperative mean of (11.99 +/- 4.48) mm Hg (t = 4.918, P < 0.001). The mean anterior chamber depth was (1.69 +/- 0.46) mm preoperatively and (2.28 +/- 0.36) mm postoperatively (t = 7.738, P < 0.001). The best-corrected visual acuity was improved in 41 of 47 eyes (87.2%).

CONCLUSION

Phacoemulsification with posterior chamber foldable intraocular lens implantation can be a good alternative in treating angle-closure glaucoma with cataract.

Why multiple small subunits (Y2 and Y4) for yeast ribonucleotide reductase? Toward understanding the role of Y4

Ribonucleotide reductases (RNRs) catalyze the conversion of nucleotides to deoxynucleotides. Class I RNRs are composed of two homodimeric subunits: R1 and R2. R1 is directly involved in the reduction, and R2 contains the diferric-tyrosyl radical (Y*) cofactor essential for the initiation of reduction. Saccharomyces cerevisiae has two RNRs; Y1 and Y3 correspond to R1, whereas Y2 and Y4 correspond to R2. Y4 is essential for diferric-Y* formation in Y2 from apoY2, Fe(2+), and O(2). The actual function of Y4 is controversial. Y2 and Y4 have been further characterized in an effort to understand their respective roles in nucleotide reduction. (His)(6)-Y2, Y4, and (His)(6)-Y4 are homodimers, isolated largely in apo form. Their CD spectra reveal that they are predominantly helical. The concentrations of Y2 and Y4 in vivo are 0.5-2.3 microM, as determined by Western analysis. Incubation of Y2 and Y4 under physiological conditions generates apo Y2Y4 heterodimer, which can form a diferric-Y small middle dot when incubated with Fe(2+) and O(2). Holo Y2Y4 heterodimer contains 0.6-0.8 Y* and has a specific activity of 0.8-1.3 micromol.min.mg. Titration of Y2 with Y4 in the presence of Fe(2+) and O(2) gives maximal activity with one equivalent of Y4 per Y2. Models for the function of Y4 based on these data and the accompanying structure will be discussed.

Structure of the yeast ribonucleotide reductase Y2Y4 heterodimer

The R2 subunits of class I ribonucleotide reductases (RNRs) house a diferric-tyrosyl radical (Y*) cofactor essential for DNA synthesis. In yeast, there are two R2 proteins, Y2 and Y4. Although both Y2 and Y4 are homologous to R2s from other organisms, Y4 lacks three conserved iron-binding residues, and its exact function is unclear. Y4 is required for assembly of the diferric-Y* cofactor in Y2, and the two proteins can form both homodimeric and heterodimeric complexes. The Y2Y4 heterodimer was crystallized from a mixture of the two proteins, and its structure was determined to 2.8 A resolution. Both Y2 and Y4 are completely alpha helical and resemble the mouse and Escherichia coli R2s in overall fold. Three alpha helices not observed in the mouse R2 structure are present at the Y2 N terminus, and one extra N-terminal helix is observed in Y4. In addition, one of the eight principal helices in both Y2 and Y4, alphaD, is shifted significantly from its position in mouse R2. The heterodimer interface is similar to the mouse R2 homodimer interface in size and interacting residues, but loop regions at the interface edges differ. A single metal ion, assigned as Zn(II), occupies the Fe2 position in the Y2 active site. Treatment of the crystals with Fe(II) results in difference electron density consistent with formation of a diiron center. No metal-binding site is observed in Y4. Instead, the residues in the active site region form a hydrogen-bonding network involving an arginine, two glutamic acids, and a water molecule.

Energy and pressure of shearing fluids at different state points

Nonequilibrium molecular dynamics simulations are reported at different strain rates (gamma) and thermodynamic state points for a shearing atomic fluid interacting via a Lennard-Jones potential. Our simulations are performed at the Lennard-Jones triple point, a point midway between the triple point and the critical point, and a high point closer to the critical temperature. We find that, for the mid-point and high point, the energy and hydrostatic pressures have strain-rate dependencies of gamma(2), in contrast to the gamma(3/2) dependencies predicted by mode coupling theory. This analytical dependence is consistent with a Taylor series expansion of these quantities as powers of the strain rate tensor. Only at the triple point does the pressure and energy display a nonanalytical dependence on gamma(3/2).

[The clinical effect of non-penetrating trabecular surgery with reticulated sodium hyaluronate implant for treatment of primary open-angle glaucoma]

OBJECTIVE

To evaluate the clinical effect of non-penetrating trabecular surgery (NPTS) with reticulated sodium hyaluronate implant in primary open-angle glaucoma (POAG).

METHODS

NPTS with reticulated sodium hyaluronate implant was performed on 27 eyes of 25 patients with POAG. The procedure consisted of excising a deep scleral tissue including the external wall of the Schlemm's canal under a scleral flap without opening the anterior chamber, as the inner wall of the canal was left in place. Then placing a 3.0 mm x 4.5 mm x 0.5 mm or 3.5 mm x 3.5 mm x 3.5 mm reticulated sodium hyaluronate implant was placed under the flap, so that the aqueous humor may filter through the thin layer of trabeculocorneal membrane spontaneously without forming a flat chamber. The postoperative intraocular pressure (IOP), inflammation and filtering bleb were analyzed. All of patients undertook ultrasound biomicroscopy (UBM) and gonioscopy to evaluate the surgical site on the postoperative 2 weeks, 3, 6 and 9 months. The mean follow-up was (6.61 plus minus 2.47) months.

RESULTS

The IOP decreased from a mean preoperative value of (26.36 +/- 9.02) mm Hg (1 mm Hg = 0.133 kPa) to a mean postoperative value of (14.18 +/- 3.51) mm Hg (t = 6.875, P < 0.05). The number of anti-glaucomatous medications, topical or systemical, was reduced from (2.96 +/- 1.43) sorts preoperatively to (0.77 +/- 1.07) sorts postoperatively. The visual acuity remained stable (no statistical difference with chi(2) test). Six eyes had elevated IOP after operation and were controlled by eyedrops or trabecular puncture with ND: YAG laser. A slight hyphema occurred in 4 eyes with small puncture during operation. The complications such as flat chamber, inflammation and choroidal detachment were not observed. The UBM showed that the sodium hyaluronate implant degraded and a transparent liquid space existed under the scleral flap in all of patients at postoperative 3 months. The gonioscopy showed that at the surgical site the thinner and semitransparent trabecular membrane and changes of a transparent cavity could be seen in 23 eyes. In the other eyes, at the site the trabecula was translucent. The filtering blebs were formed in 8 eyes.

CONCLUSION

Non-penetrating trabecular surgery with reticulated sodium hyaluronate implant can effectively lower the IOP and reduce the sorts of anti-glaucomatous medications. The visual acuity may remain unchanged, and no serious complications commonly seen in the traditional trabeculectomy occur. The procedure is a new simple and effective one for the treatment of POAG.

[A study on susceptibility of different layers of rabbit retina to ocular hypertension]

OBJECTIVE

To investigate the histological damage and its degrees of different layers of rabbit retina induced by ocular hypertension.

METHODS

The intraocular pressure (IOP) was elevated by intracameral injection of 0.10 - 0.15 ml of 2% methylcellulose in sixteen gray rabbits. The rabbit eyes were enucleated, fixed, and paraffin-embedded. For histological evaluation, the slides were stained with hematoxylin-eosin, examined by light microscopic and computer automatic image analysis.

RESULTS

The quantitative analysis indicated that all of the retinal layers have different degrees of histopathological damage. Among them, the retinal ganglion cells (RGCs) and retinal nerve fiber layer (RNFL) were most severely damaged, with the decrease rate of 74.3% and 61.9%, respectively. The decrease rates of other retinal layers were as follows: the retinal inner layer, 42.4%; the whole sensory layer of the retina, 35.0% and the outer layer, 24.2%. We also found a significant correlation between RGCs loss and RNFL thinning (r = 0.68, P < 0.01), demonstrating a strong correlation between IOP level and RNFL thickness (F = 8.97, P < 0.01).

CONCLUSION

All of the anatomic layers of retina can suffer from degeneration and atrophy at different degrees.

[Influence of cell cycle in human trabecular cells induced by dexamethsone]

PURPOSE

To investigate the influence of dexamethesone (Dex) on cell cycle in human trabecular cells(HTC).

METHODS

The trabecular specimens from human eyes were cultured in vitro. Then the cultured cells were immersed in DMEM solution containing 10(-7) M dexamethesone for three, five and seven days. The cell cycle was detected by Flow Cycometry.

RESULTS

The G2 phase of cell cycle in HTC increased when HTC were treated by Dex. The G2 phase was 2% in control group. For three, five and seven days treated by Dex, the G2 phase were 8%, 16.3 and 19.4%.

CONCLUSION

The influence of cell cycle might be induced by Dex, it may be related with the pathogenesis of glucocorticoid induced glaucoma.

Surgical correction of hyperopia: clear lens extraction and laser correction

Modern ophthalmology offers a series of surgical procedures to correct a wide range of hyperopia and hyperopic astigmatism. Varies excimer lasers and thermal lasers have been proven safe and effective. Phakic implants and clear lens extraction offers alternatives for moderate to high hyperopic patients. Indications, techniques, and clinical study results were reviewed and summarized.

[Phacoemulsification in patients with cataract and overfiltering bleb after antiglaucoma surgery]

PURPOSE

To evaluate the effect of phacoemulsification in patients with cataract, overfiltering bleb, and low-tension after antiglaucoma surgery.

METHODS

Phacoemulsification and implantation of a foldable intraocular len was performed in six patients(7 eyes) with overfiltering bleb, low-tension, and cataract. The complications, blebs, intraocular pressures(IOP), and visual acuity were observed postoperatively.

RESULTS

No severe complication was found. The overfiltering blebs constricted and their walls became thicker three months after the operation. The visual acuity and IOP were improved (P < 0.05).

CONCLUSION

Phacoemulsification may be another way to treat the patients with cataract and overfiltering bleb, low-tension after antiglaucoma surgery.

Plaque distribution and vascular remodeling of ruptured and nonruptured coronary plaques in the same vessel: an intravascular ultrasound study in vivo

OBJECTIVES

This study was designed to identify potential differences between the intravascular ultrasound (IVUS) characteristics of spontaneously ruptured and nonruptured coronary plaques.

BACKGROUND

The identification of vulnerable plaques in vivo may allow targeted prevention of acute coronary events and more effective evaluation of novel therapeutic approaches.

METHODS

Intravascular ultrasound was used to identify 29 ruptured plaques in arteries containing another nonruptured plaque in an adjacent segment. Intravascular ultrasound characteristics of these plaques were compared with plaques of computer-matched controls without evidence of plaque rupture. Plaque distribution was assessed by measuring the eccentricity of lumen location (inside the total vessel). Lumen cross-sectional area narrowing was calculated as [1 - (target/reference lumen area)] x 100%. A remodeling index was calculated as lesion/reference arterial area (>1.05 = compensatory enlargement, <0.95 = shrinkage).

RESULTS

Among the three groups of plaques, there was no significant difference in quantitative angiographic parameters, IVUS reference dimensions and IVUS lumen cross-sectional area narrowing. There was a difference in plaque distribution; lumen location by IVUS was significantly more eccentric in ruptured than in nonruptured (p = 0.002) and control plaques (p < 0.0001). The arc of disease-free vessel wall was larger in ruptured than in control plaques (p < 0.0001). The remodeling pattern of ruptured and nonruptured plaques differed significantly from that of the control plaques (p = 0.0001 and 0.003); compensatory enlargement was found in 66%, 48%, and 17%, whereas shrinkage was found in 7%, 10% and 48%, respectively.

CONCLUSIONS

Intravascular ultrasound assessment of plaque distribution and vascular remodeling may help to classify plaques with the highest probability of spontaneous rupture.

[Primary study on heart rate variability of non-linear dynamics in patients with coronary artery disease and diabetes]

This is a comparative study on the non-linear dynamics between 30 healthy controls and three groups of patients with single coronary artery disease(n = 20), multi-coronary disease(n = 8), and diabetic patients with diabetic autonomic neuropathy (DAN)(n = 18), respectively. We selected and adopted six quantity indices of dispersed-dot plot, including the area of plot (SQ), long-axis (LA), short-axis (SA), the angle of long-axis and short-axis (ALS), vector length index (VLI) and vector angle index (VAI), and Kolmogorov entropy and fractal dimension. We found that the non-linear indices in healthy control had obvious day-to-night change, while the change in coronary artery disease patients decreased and disappeared in diabetics. By the findings that both coronary artery disease patients and diabetic patients had the turbulence of vegetal nerve system, we concluded that the vegetal nerve activity might be an important factor in heart non-linear dynamics. And marked differences in the non-linear indices were seen between the normal control, the single-vessel, multi-vessel coronary artery disease patients, and the diabetic patients, thus suggesting that these indices may be used in clinical practice.

Abnormal Coronary Flow Velocity Reserve After Coronary Intervention Is Associated With Cardiac Marker Elevation

Background —Residual reduction of relative coronary flow velocity reserve (rCVR) after successful coronary intervention has been related to microvascular impairment. However, the incidence of cardiac enzyme elevation as a surrogate marker of an underlying embolic myocardial injury in these cases has not been studied.

Methods and Results —A series of 55 consecutive patients with successful coronary stenting, periprocedural intracoronary Doppler analysis, and determination of creatine kinase (CK; upper limit of normal [ULN] for women 70 IU/L, for men 80 IU/L) and cardiac troponin T (cTnT; bedside test, threshold 0.1 ng/mL) before and 6, 12, and 24 hours after intervention were studied. Postprocedural rCVR was the only intracoronary Doppler parameter that independently correlated with cTnT ( r =−0.498, P <0.001) and CK outcome ( r =−0.406, P =0.002). Receiver operating characteristic analysis identified a postprocedural rCVR of 0.78 as the best discriminating value, with a sensitivity of 83.3% and 69.2% and a specificity of 79.1% and 76.2% for detection of cTnT and CK elevation, respectively. Stratified according to this cutoff value, the incidence of cTnT elevation was 52.6% in patients with (n=19) and 5.6% in patients without (n=36) a postprocedural rCVR <0.78 ( P <0.001), associated with a CK elevation >1 times the ULN in 36.8% and 5.6% ( P =0.005) of patients, respectively.

Conclusions —Cardiac marker elevation can frequently be found after coronary procedures that are associated with a persistent reduction of rCVR, indicating procedural embolization of atherothrombotic debris with microvascular impairment and myocardial injury as a potential underlying mechanism.