Characteristics and outcomes of patients with percutaneous coronary intervention for unprotected left main coronary artery disease: a Hong Kong experience.

OBJECTIVE: To evaluate the intermediate-term outcomes of patients with unprotected left main coronary artery stenosis who were treated with percutaneous coronary intervention in Hong Kong. DESIGN: Historical cohort. SETTING: A regional hospital in Hong Kong. PATIENTS: Patients with unprotected left main coronary artery disease undergoing stenting with bare-metal stents or drug-eluting stents between January 2008 and September 2011. MAIN OUTCOME MEASURES: Incidence of restenosis and major adverse cardiac and cerebrovascular events including cardiac death, non-fatal myocardial infarction, stroke, and target lesion revascularisation. RESULTS: Of the 111 patients included in the study, 86 received drug-eluting stents and 25 received bare-metal stents. Procedural success was achieved in 98.2% of cases. Angiographic follow-up was available in 83.8% of cases and restenosis rate was significantly lower with drug-eluting stents than with bare-metal stents (14.0% vs 40.0%; P=0.004). After a mean clinical follow-up of 26.1 (standard deviation, 12.6) months, the incidences of cardiac death (5.8% vs 16.0%; P=0.191) and non-fatal myocardial infarction (3.5% vs 8.0%; P=0.262) were similar between drug-eluting stents and bare-metal stents. However, the risks of target lesion revascularisation (9.3% vs 32.0%; P=0.001) and major adverse cardiac and cerebrovascular events (19.8% vs 44.0%; P=0.004) were significantly lower with drug-eluting stents than with bare-metal stents. CONCLUSIONS: Performing percutaneous coronary intervention for unprotected left main coronary artery disease was safe and feasible in selected patients with high procedural success rate. The incidence of major adverse cardiac and cerebrovascular events in patients receiving drug-eluting stents remains low after intermediate-term follow-up. Compared with bare-metal stents, drug-eluting stents were associated with a lower need for repeating revascularisation without increasing the risk of death or myocardial infarction in patients with unprotected left main coronary artery disease.

A size of approximately 1 au for the radio source Sgr A* at the centre of the Milky Way.

Although it is widely accepted that most galaxies have supermassive black holes at their centres, concrete proof has proved elusive. Sagittarius A* (Sgr A*), an extremely compact radio source at the centre of our Galaxy, is the best candidate for proof, because it is the closest. Previous very-long-baseline interferometry observations (at 7 mm wavelength) reported that Sgr A* is approximately 2 astronomical units (au) in size, but this is still larger than the 'shadow' (a remarkably dim inner region encircled by a bright ring) that should arise from general relativistic effects near the event horizon of the black hole. Moreover, the measured size is wavelength dependent. Here we report a radio image of Sgr A* at a wavelength of 3.5 mm, demonstrating that its size is approximately 1 au. When combined with the lower limit on its mass, the lower limit on the mass density is 6.5 x 10(21)M(o) pc(-3) (where M(o) is the solar mass), which provides strong evidence that Sgr A* is a supermassive black hole. The power-law relationship between wavelength and intrinsic size (size proportional, variantwavelength(1.09)) explicitly rules out explanations other than those emission models with stratified structure, which predict a smaller emitting region observed at a shorter radio wavelength.

Molecular gas in the host galaxy of a quasar at redshift z = 6.42.

Observations of molecular hydrogen in quasar host galaxies at high redshifts provide fundamental constraints on galaxy evolution, because it is out of this molecular gas that stars form. Molecular hydrogen is traced by emission from the carbon monoxide molecule, CO; cold H2 itself is generally not observable. Carbon monoxide has been detected in about ten quasar host galaxies with redshifts z > 2; the record-holder is at z = 4.69 (refs 1-3). Here we report CO emission from the quasar SDSS J114816.64 + 525150.3 (refs 5, 6) at z = 6.42. At that redshift, the Universe was only 1/16 of its present age, and the era of cosmic reionization was just ending. The presence of about 2 x 1010 M\circ of H2 in an object at this time demonstrates that molecular gas enriched with heavy elements can be generated rapidly in the youngest galaxies.

Color cone lasing emission in a dye-doped cholesteric liquid crystal with a single pitch.

This work investigates a novel color cone lasing emission (CCLE) based on a one-dimensional photonic crystal-like dye-doped cholesteric liquid crystal (DDCLC) film with a single pitch. The lasing wavelength in the CCLE is distributed continuously at 676.7-595.6 nm, as measured at a continuously increasing oblique angle relative to the helical axis of 0-50 degrees . This work demonstrates that lasing wavelength coincides exactly with the wavelength at the long wavelength edge of the CLC reflection band at oblique angles of 0-50 degrees . Simulation results of dispersion relations at different oblique angles using Berreman's 4X4 matrix method agrees closely with experimental results. Some unique and important features of the CCLE are identified and discussed.

The galactic center: is it a massive black hole?

Studies of active galactic nuclei constitute one of the major efforts in astronomy. Massive black holes are the most likely source for the enormous energy radiated from such nuclei. Observations reviewed here suggest unusual activity and the possible existence of a massive black hole in the nucleus of our galaxy. Because of its proximity to Earth, our galactic nucleus can be observed in unsurpassed detail and may serve as the Rosetta stone both for deciphering active galactic nuclei and for confirming the existence of a massive black hole.

Upper limit of 3.3 astronomical units to the diameter of the galactic center radio source sgr a*.

Sagittarius (Sgr) A(*) is a unique radio source located at the center of our galaxy. The radiation from Sgr A(*) may be generated in matter accreting onto a massive black hole. In observations at long wavelengths, the apparent angular size of Sgr A(*) decreases in the manner expected for emission from a point source scattered by electron density fluctuations along the line of sight. Measurements at a wavelength of 7 millimeters with the nearly completed Very Long Baseline Array indicate a size of 0.7 milliarc seconds, which is consistent with an extrapolation from results at longer wavelengths. The true size of Sgr A(*) must be less than 0.4 milliarc seconds, or 3.3 astronomical units. The inferred black hole mass is less than 1.5 x 10(6) solar masses according to a recent model for the emission.

A Transient Radio Source near the Center of the Milky Way Galaxy.

In late December 1990, a new radio source appeared near the center of our galaxy rivaling the intensity of Sgr A(*) (the compact radio source at the galactic center). Following its first detection, the flux density of the galactic center transient (GCT) increased rapidly to a maximum 1 month later, and then declined gradually with a time scale of about 3 months. Surprisingly, the GCT maintained a steep radio spectrum during both its rising and decay phases. The neutral hydrogen (HI) absorption shows similar absorption to that in front of Sgr A(*); this indicates that the GCT lies near the galactic center. Furthermore, both HI and OH observations show an additional deep absorption at +20 kilometers per second with respect to the local standard of rest. Thus, the GCT is either embedded in or located behind a molecular cloud moving with that velocity. The cloud can be seen on infrared images. Its opacity is shown to be inadequate to conceal a supernova near the galactic center. It is argued that the GCT was probably transient radio emission from synchrotron-radiating plasma associated with an x-ray binary system.

Refractory thrombotic thrombocytopenic purpura and membranoproliferative glomerulonephritis successfully treated with rituximab: a case associated with hepatitis C virus infection.

Plasmapheresis remains the main treatment modality for patients with thrombotic thrombocytopenic purpura. We report a patient who had simultaneous onset of membranoproliferative glomerulonephritis and thrombotic thrombocytopenic purpura. She did not improve after 48 plasmapheresis sessions. A 6-week course of weekly intravenous doses of rituximab was then given. This achieved complete remission of her nephrotic syndrome and improvement in her renal function, so plasmapheresis was ceased. She had a low ADAMTS13 antigen level and a positive ADAMTS13 antibody, both of which reverted to normal after treatment with rituximab. This coincided with a rise in her hepatitis C virus RNA and liver transaminases. Liver biopsies did not reveal active fibrosis. Her hepatitis C virus RNA titre dropped afterwards, and she had no relapses of her thrombotic thrombocytopenic purpura and nephrotic syndrome, for more than 2 years after remission. The simultaneous onset and successful outcomes of both the membranoproliferative glomerulonephritis and thrombotic thrombocytopenic purpura illustrate the usefulness of rituximab. We discuss its use and risks, in the context of chronic hepatitis C infection.

Similarities in the formation and removal of covalent DNA adducts in benzo(a)pyrene-treated BALB/3T3 variant cells with different induced transformation frequencies.

Classes of cell variants isolated from BALB/3T3-A31 clone 1 showing high, intermediate, and low susceptibility to ultraviolet light-induced transformation also demonstrated a differential response to benzo(a)pyrene (BP)-induced transformation. On the other hand, these variants showed an identical susceptibility to the killing effect of these carcinogens. The extent of BP binding to DNA was found to be very similar in all three classes of variants under transforming conditions. BP:DNA adducts from the variant cells were analyzed by high-pressure liquid chromatography. The same adducts (N2-(10S-[7R,8S,9R-trihydroxy-7,8,9,10-tetrahydrobenzo(a)pyrene]yl)deoxyguanosine and a minute amount of the 7S enantiomer) were detected in the highly susceptible, the intermediately susceptible, and the resistant variant clones. Removal of the BP:DNA adduct occurred at an equally slow rate in all three classes of variant cells. These results indicate that the formation of stable covalent DNA adducts is not a sufficient condition for induction of transformation. Processes other than formation and removal of the stably bound BP:DNA covalent adducts are thus major factors controlling the susceptibility of BALB/3T3-A31 clone 1 variant cells to BP-induced transformation.

Successful treatment of IgA nephropathy in association with low-grade B-cell lymphoma of the mucosa-associated lymphoid tissue type.

Kidney and the urogenital tract are among the various mucosal sites involved in mucosa-associated lymphoid tissue (MALT) lymphoma. We report a case with simultaneous onset of crescentic immunoglobulin (Ig) A nephropathy and gastrointestinal low-grade B-cell lymphoma of the MALT type with kidney infiltration. M-component of IgM lambda was detected in the serum, and the renal biopsy specimen showed monotypic lambda light chain staining in the lymphoma cells but not the glomeruli. The heavy proteinuria and impaired creatinine clearance returned to normal, and microscopic hematuria disappeared 20 months after treatment with chlorambucil as single-agent chemotherapy. This coincided with a complete resolution of the gastric and renal lymphoma infiltration. The close association of both the onset and successful outcome of the two entities thus support their possible causal relationship, and we discuss the possibility of an association of the disturbance of the MALT by the lymphoma cells with the pathogenesis of IgA nephropathy.

Randomized prospective study of the effect of increased dialytic dose on nutritional and clinical outcome in continuous ambulatory peritoneal dialysis patients.

Cohort studies have shown that greater urea (Kt/V) and creatinine clearances (CCr) were associated with better survival in patients on continuous ambulatory peritoneal dialysis (CAPD). The possibility of improved patient outcome with increased dialytic dose remains unknown. We prospectively studied over 1 year the effects of an extra 2-L bag on the outcome of 82 patients undergoing three daily 2-L exchanges for at least 12 months. At 1 year, 36 patients were undergoing 6-L exchanges, whereas 30 patients underwent 8-L exchanges. The increased dialytic dose resulted in increased total weekly Kt/V (TKt/V; 1.82 to 2.02), whereas total weekly CCr (TCCr) was maintained (63.2 to 61.9 L/1.73 m(2)). Control patients had reduced solute clearances (TKt/V, 1.87 to 1.67; TCCr, 64.8 to 54.6 L/1.73 m(2)). The fourth bag exchange resulted in a significant increase in net ultrafiltration (0.83 to 1.51 L/d), whereas the control group also had greater ultrafiltration (0.68 to 1.01 L/d) after 1 year. Although the normalized protein equivalent of nitrogen appearance (nPNA) was stable in the controls, the patients using 8-L exchanges achieved a greater nPNA (1.10 to 1.24 g/kg/d). There was no associated change in serum albumin levels (3.79 to 3.48 g/dL). The hospitalization rate increased in the controls (0.9 to 1.8 admissions/12 mon), whereas it was unchanged in the patients using 8-L exchanges. In conclusion, a 33% increase in dialytic prescription led to increased peritoneal and total clearances. Despite achieving increased nPNA (13%), the serum albumin level was unchanged. However, the increased hospitalization rate observed in the controls was avoided in the group using 8-L exchanges.

A retrospective study of seven cases of Candida parapsilosis peritonitis in CAPD patients: the therapeutic implications.

BACKGROUND: Candida peritonitis accounts for the majority of fungal peritonitis in continuous ambulatory peritoneal dialysis (CAPD), but the Candida species were not routinely subtyped in previous studies. The clinical course and the outcome of Candida parapsilosis peritonitis remain unclear. OBJECTIVE: To study the clinical course and outcome of C. parapsilosis peritonitis in CAPD patients. SETTING: Peritoneal dialysis unit in a regional hospital. PATIENTS AND DESIGN: A retrospective study on seven cases of C. parapsilosis peritonitis occurring in a single center over 3 years. RESULTS: The 7 patients included 4 males and 3 females. Their mean age was 62 +/- 11.5 years. Two (29%) were diabetic. Three (43%) had a history of preceding peritonitis and 5 (71 %) had received broad spectrum antibiotic within the previous 1 month. All presented with cloudy dialysate, abdominal pain, and fever. The mean dialysate white cell count was 300 +/- 168/mm3 with a predominance of neutrophils (81.4% +/- 13.1%). The mean time from onset of symptoms to diagnosis was 5.7 +/- 3.1 days. All had been treated with immediate catheter removal within 24 hours of diagnosis and antifungal therapy, including oral fluconazole, intravenous (IV) amphotericin, or their sequential combination. Environmental samplings were negative for C. parapsilosis. The overall complication rate was exceptionally high (71%), with three (43%) complicated by abscess formation requiring surgical drainage, one peritoneal adhesion (14%), and one mortality (14%). In the end, only two (29%) could resume CAPD. CONCLUSIONS: The outcome of this study group appeared worse than those previously described in the literature, and the optimal treatment for this group of patients remains unclear.

Single-incision nephroureterectomy combined with transurethral incision of bladder cuff for renal pelvic tumor.

With the extended use of transurethral endoscopic surgery, we modified the conventional nephroureterectomy that usually requires either a very long incision or two separate shorter incisions. From August 1983 to October 1988, 13 cases of renal pelvic tumor in this hospital were treated single-incision nephroureterectomy combined with transurethral incision of the bladder cuff. The advantages of this technique were less surgical time and a decrease in postoperative wound pain. There were no significant complications or local recurrence noted in this series. The proposed indications were urothelial tumors in the renal pelvis and upper ureter without demonstrable metastases. Tumors of an uncertain cell type preoperatively are especially indicated. The details of this technique are described.

Recombinant human erythropoietin (rHuEPO) therapy has no effect on peritoneal transport in CAPD patients: a short-term study.

While theoretically the vasoconstriction associated with the rise in hemoglobin (Hb) level may potentially alter peritoneal transport characteristics, the effect of recombinant human erythropoietin (rHuEPO) therapy on peritoneal transport in continuous ambulatory peritoneal dialysis (CAPD) patients remains unclear. We have therefore performed a prospective study on the short-term effect of rHuEPO on the peritoneal transport characteristics in terms of the change in corrected dialysate/plasma creatinine (D/Pcr) in the fast peritoneal equilibration test (PET). Eight consecutive CAPD patients started on rHuEPO had fast PETs performed before and 4 to 6 months after the initiation of rHuEPO therapy. Another 8 CAPD patients with stable Hb levels not receiving rHuEPO served as a control group. All patients (study and control) had been on CAPD therapy for more than 3 months upon enrollment, and none had peritonitis during the study period. Patients receiving rHuEPO showed significant increase in Hb level, while the Hb levels of those in the control group remained unchanged. Neither the study nor the control group patients showed significant change in the corrected D/Pcr value over a mean observation period of 5.25 +/- 0.89 months. While rHuEPO appears to be effective in increasing the Hb level in CAPD patients, there is no significant impact on the corrected D/Pcr in the fast PET test observed in this short-term study.

Primary hyperoxaluria: a rare but important cause of nephrolithiasis.

We report on a middle-aged man with end-stage renal failure apparently secondary to recurrent renal stones. He developed systemic oxalosis soon after commencing dialysis. The diagnosis of primary hyperoxaluria type 1 was supported by the finding of high dialysate glycolate excretion. The patient subsequently received an isolated cadaveric renal transplant, but the outcome was a rapid recurrence of oxalosis and early graft failure. Although isolated liver or renal transplantation in addition to various adjuvant measures may be considered in the early stage, combined liver-kidney transplantation remains the only definitive therapy for a patient with end-stage renal failure and systemic oxalosis due to hyperoxaluria type 1. This case illustrates the possible late presentation of primary hyperoxaluria type 1 and the poor outcome with isolated renal transplantation after the development of systemic oxalosis. One should thus have a high index of suspicion in patients with recurrent renal stones of this rare, but nevertheless important, entity.

Factors associated with poorly-controlled hypertension in continuous ambulatory peritoneal dialysis patients.

INTRODUCTION: Hypertension is highly prevalent among continuous ambulatory peritoneal dialysis (CAPD) patients and is a major risk factor for cardiovascular complications. This study examines the risk factors associated with poorly-controlled hypertension in CAPD. METHODS: We performed a cross-sectional study of 66 stable adult CAPD patients to evaluate their hypertension control over a period of three to four months and their associations with other clinical and laboratory parameters. RESULTS: The mean age of the patients was 56.7 (plus or minus 1.27) years. Their mean systolic and diastolic blood pressure were 139 (plus or minus 2.59) mmHg and 77 (plus or minus 1.35) mmHg respectively; 71 percent of them were on antihypertensive drugs. Thirty (45.5 percent) patients had high blood pressure greater than 140/90mmHg. Compared with patients with normal blood pressure, patients with high blood pressure received significantly more antihypertensive drugs (p-value equals 0.034) and were more likely to be clinically overloaded (p-value less than 0.001). Multivariate analysis showed that systolic blood pressure was predicted by volume expansion (p-value less than 0.001) while diastolic blood pressure was negatively predicted by age (p-value equals to 0.004). In addition, volume overload was predicted positively by dialysate/plasma creatinine (p-value equals 0.011) and negatively by serum albumin (p-value less than 0.001). CONCLUSION: Clinically-apparent volume overload was associated with poor systolic blood pressure control despite aggressive antihypertensive drug therapy. This finding underlines the importance of fluid control and could provide an explanation of the poor outcome observed in patients with high peritoneal transport.

A retrospective study on efficacy of proton-pump inhibitor-based triple therapy for eradication of Helicobacter pylori in patients with chronic renal failure.

OBJECTIVE: The efficacy of short-course triple eradication therapy has been documented in patients with Helicobacter pylori infection and normal renal function. We have evaluated a one-week proton-pump inhibitor-based triple therapy for Helicobacter pylori eradication in a retrospective review of patients with chronic renal failure. METHODS: We studied 25 patients (mean age 65.1 +/- 2.4 years) with creatinine clearance <30 ml/min/1.73 m2 or serum creatinine level >200 micromol/L (13 on dialysis), who had Helicobacter pylori infection, documented by histological examination or rapid urease test, together with either peptic ulcer disease or severe gastritis. The combination of Omeprazole 20 mg BID or Lansoprazole 30 mg BID, amoxicillin 1 gm BID and clarithromycin 500 mg BID was given for one week, in addition to therapy for peptic ulcers. All patients were re-endoscoped four weeks later. RESULTS: All but one patient (96%) had successful eradication. On repeat endoscopy, all 13 patients with peptic ulcers had healed ulcers. For the 12 gastritis patients, three became normal and nine had persistent gastritis. For patients not on dialysis, the serum creatinine level and creatinine clearance remained stable at two weeks after treatment (303 +/- 37 vs. 330 +/- 36 micromol/l, p=ns; 23.6 +/- 3.4 vs. 26.0 +/- 3.9 ml/min/1.73 m2, p=ns, respectively). CONCLUSION: The short course triple therapy was highly efficacious for Helicobacter pylori eradication in patients with chronic renal failure, with no adverse effect on renal function.

KIF1A is the primary anterograde motor protein required for the axonal transport of dense-core vesicles in cultured hippocampal neurons.

Dense-core vesicles (DCVs) are responsible for transporting, processing, and secreting neuropeptide cargos that mediate a wide range of biological processes, including neuronal development, survival, and learning and memory. DCVs are synthesized in the cell body and are transported by kinesin motor proteins along microtubules to pre- and postsynaptic release sites. Due to the dependence on kinesin-based transport, we sought to determine if the kinesin-3 family member, KIF1A, transports DCVs in primary cultured hippocampal neurons, as has been described for invertebrate neurons. Two-color, live-cell imaging showed that the DCV markers, chromogranin A-RFP and BDNF-RFP, move together with KIF1A-GFP in both the anterograde and retrograde directions. To demonstrate a functional role for KIF1A in DCV transport, motor protein expression in neurons was reduced using RNA interference (shRNA). Fluorescently tagged DCV markers showed a significant reduction in organelle flux in cells expressing shRNA against KIF1A. The transport of cargo driven by motors other than KIF1A, including mitochondria and the transferrin receptor, was unaffected in KIF1A shRNA expressing cells. Taken together, these data support a primary role for KIF1A in the anterograde transport of DCVs in mammalian neurons, and also provide evidence that KIF1A remains associated with DCVs during retrograde DCV transport.

Prognostic value of adenosine stress myocardial perfusion by cardiac magnetic resonance imaging in patients with known or suspected coronary artery disease.

BACKGROUND: Cardiac magnetic resonance imaging (CMR) has been intensely researched in recent years, and its high diagnostic accuracy for myocardial ischemia has been demonstrated. However, its prognostic information is very limited. AIM: We sought to assess the value of adenosine stress myocardial perfusion by CMR in predicting cardiac events in patients with known or suspected coronary artery disease (CAD). DESIGN: Retrospective study. METHODS: From January 2003 to December 2008, we retrospectively reviewed consecutive patients with or without history of CAD referred for evaluation of suspected myocardial ischemia who had undergone adenosine stress CMR in our hospital. End points were cardiac death or non-fatal myocardial infarction (MI). RESULTS: After a mean follow-up of 3.2 ± 1.6 years in 203 patients, 15 (7.4%) cardiac events occurred. The 4-year event-free survival was 96.2% for patients with normal stress CMR perfusion and 71.5% for those with abnormal stress CMR perfusion. Univariate analysis showed that both adenosine-induced reversible perfusion defect and delayed gadolinium enhancement by CMR were significant predictors of cardiac events [Hazard ratio (HR) 9.31; 95% Confidence Interval (95% CI) 3.18-27.3; and HR 9.24; 95% CI 3.27-26.08; P < 0.001, respectively). By multivariate analysis, adenosine-induced reversible perfusion defect remained an independent predictor of cardiac events (HR 7.77; 95% CI 2.50-24.18; P < 0.001). In a stepwise multivariate model (Cox regression), an abnormal stress CMR perfusion result had significant incremental predictive value over clinical risk factors and resting regional wall motion abnormality (RWMA) (P < 0.001). CONCLUSION: In patients with known or suspected CAD, adenosine stress CMR could be used to identify patients at high risk for subsequent cardiac death or nonfatal MI. A normal CMR perfusion was associated with a very low long-term event rate and excellent long-term prognosis. In addition, stress CMR perfusion provided important incremental prognostic information over clinical risk factors and RWMA.

An antimutator deoxyribonucleic acid polymerase. I. Purification and properties of the enzyme.

The DNA polymerase induced by an antimutator T4 phage has been purified to apparent homogeneity and has been compared to the wild type polymerase. The mutant enzyme resembles the wild type in thermal stability, pH optimum, salt activation, divalent metal ion requirement, inhibition by a sulfhydryl reagent, and apparent affinity for DNA. However, the mutant enzyme differs from the wild type in its 8-fold higher 3'-exonuclease activity and in its decreased apparent affinity for deoxyribonucleoside triphosphates. Inhibition studies indicate that the exonuclease of the mutant enzyme is more vulnerable to physical and chemical modification than its wild type counterpart.