Sodium Glucose Transporter 2 Inhibitors Versus Metformin on Cardiovascular and Renal Outcomes in Patients With Diabetes With Low Cardiovascular Risk: A Nationwide Cohort Study

BACKGROUND

This study investigated whether initial SGLT2 (sodium-glucose cotransporter 2) inhibitor-based treatment is superior to metformin-based regimens as a primary prevention strategy among low-risk patients with diabetes.

METHODS AND RESULTS

In this nationwide cohort study, a total of 38 496 patients with diabetes with low cardiovascular risk were identified (age 62.0±11.6 years, men 50%) from January 1 to December 31, 2016. Patients receiving SGLT2 inhibitors-based and metformin-based regimens were 1:2 matched by propensity score. Study outcomes included all-cause mortality, cardiovascular death, hospitalization for heart failure, stroke, and progression to end-stage renal disease. Compared with 1928 patients receiving metformin-based regimens, 964 patients receiving SGLT2 inhibitor-based regimens had similar all-cause mortality (hazard ratio [HR], 0.75 [95% CI, 0.51-1.12]), cardiovascular death (HR, 0.69 [95% CI, 0.25-1.89]), hospitalization for heart failure (HR, 1.06 [95% CI, 0.59-1.92]), stroke (HR, 0.78 [95% CI, 0.48-1.27]), and progression to end-stage renal disease (HR, 0.88 [95% CI, 0.32-2.39]). However, SGLT2 inhibitors were associated with a lower risk of all-cause mortality (HR, 0.47 [95% CI, 0.23-0.99]; P for interaction=0.008) and progression to end-stage renal disease (HR, 0.22 [95% CI, 0.06-0.82]; P for interaction=0.04) in patients under the age of 65.

CONCLUSIONS

In comparison to metformin-based regimens, SGLT2 inhibitor-based regimens showed a similar risk of all-cause mortality and adverse cardiorenal events. SGLT2 inhibitors might be considered as first-line therapy in select low-risk patients, for example, younger patients with diabetes.

Oxidative stress mediates the inhibitory effects of Manzamine A on uterine leiomyoma cell proliferation and extracellular matrix deposition via SOAT inhibition

Uterine fibroids, the most common benign tumors of the myometrium in women, are characterized by abnormal extracellular matrix deposition and uterine smooth muscle cell neoplasia, with high recurrence rates. Here, we investigated the potential of the marine natural product manzamine A (Manz A), which has potent anti-cancer effects, as a treatment for uterine fibroids. Manz A inhibited leiomyoma cell proliferation in vitro and in vivo by arresting cell cycle progression and inducing caspase-mediated apoptosis. We performed target prediction analysis and identified sterol o-acyltransferases (SOATs) as potential targets of Manz A. Cholesterol esterification and lipid droplet formation were reduced by Manz A, in line with reduced SOAT expression. As a downstream target of SOAT, Manz A also prevented extracellular matrix deposition by inhibiting the β-catenin/fibronectin/metalloproteinases axis and enhanced autophagy turnover. Excessive free fatty acid accumulation by SOAT inhibition led to reactive oxygen species to impair mitochondrial oxidative phosphorylation and trigger endoplasmic reticulum stress via PERK/eIF2α/CHOP signaling. The inhibitory effect of ManzA on cell proliferation was partially restored by PERK knockdown and eliminated by tauroursodeoxycholic acid, suggesting oxidative stress plays a critical role in the mechanism of action of Manz A. These findings suggest that targeting SOATs by Manz A may be a promising therapeutic approach for uterine fibroids.

Left ventricular assist device exchange from HeartMate II to HeartMate 3 in an Asian patient-a case report and literature review

BACKGROUND

Pump exchange surgery of left ventricular assist device (LVAD) has been demonstrated in several studies; however, information for Asian patients was limited.

CASE PRESENTATION

A 63-year-old man underwent a pump upgrade from HeartMate II to HeartMate 3 for driveline damage through limited left anterior thoracotomy and lower partial sternotomy. He did not experience any hemodynamic adverse events or device malfunction during postoperative follow-ups of 12 months. We also reviewed all published cases with HeartMate II exchange to HeartMate 3.

CONCLUSIONS

The case demonstrated that it was safe and feasible to perform HMII LVAD exchange to HM3 through a limited approach for Asian patients.

Decreased Expression of Plakophilin-2 and αT-Catenin in Arrhythmogenic Right Ventricular Cardiomyopathy: Potential Markers for Diagnosis

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a hereditary disease of the heart muscle. Clinical challenges remain, however, in identifying patients with ARVC in the early or concealed stages with subtle clinical manifestations. Therefore, we wanted to identify potential targets by immunohistochemical (IHC) analysis in comparison with controls. Pathogenic mutations were identified in 11 of 37 autopsied patients with ARVC. As observed from IHC analysis of the RV, expression of αT-catenin and plakophilin-2 is significantly decreased in autopsied patients with ARVC as compared to controls, and the decreased expression is consistent in patients with and without pathogenic mutations. Furthermore, ARVC specimens demonstrated a reduced localization of αT-catenin, desmocollin-2, desmoglein-2, desmoplakin, and plakophilin-2 on intercalated discs. These findings have been validated by comparing RV specimens obtained via endomyocardial biopsy between patients with ARVC and those without. The pathogenic mutation was present in 3 of 5 clinical patients with ARVC. In HL-1 myocytes, siRNA was used to knockdown CTNNA3, and western blotting analysis demonstrated that the decline in αT-catenin expression was accompanied by a significant decline in the expression of plakophilin-2. The aforementioned effect was directed towards protein degradation rather than mRNA stability. Plakophilin-2 expression decreases concurrently with the decline in CTNNA3 expression. Therefore, the expression of αT-catenin and plakophilin-2 could be potential surrogates for the diagnosis of ARVC.

Midterm result of custom-made iliac branch device for common iliac aneurysm with and without abdominal aortic aneurysm

OBJECTIVES

Although commercial iliac branch devices offer a new and valid endovascular approach to treating iliac aneurysm and effectively preserve antegrade flow of the internal iliac artery, their use may not be suited for all types of challenging anatomy, especially isolated common iliac artery aneurysm. Our custom-made iliac bifurcation device has a unique design and excludes both combined and isolated iliac branch aneurysm. This study validated the efficacy and safety of the custom device by comparing clinical outcomes between groups receiving commercial and custom devices.

METHODS

Data of consecutive patients receiving iliac bifurcation device implantation for iliac aneurysm with or without concomitant endovascular repair for abdominal aortic aneurysm from January 2010 to May 2019 were reviewed.

RESULTS

Iliac bifurcation device implantation with or without concomitant abdominal aortic aneurysm stent grafting was completed in 46 patients (commercial, n = 35; custom, n = 11). No significant differences were observed regarding postoperative complications, occlusion or endoleak. Comparisons of primary (80.8% vs 85.7%, P = 0.88) and secondary (86.5% vs 85.7%, P = 0.85) patency and freedom from reintervention (88.2% vs 100%, P = 0.33), all-cause mortality (78.6% vs 100%, P = 0.25) and aneurysm-related mortality (100% vs 100%, P = 1.00) also indicated no differences at a 5-year surveillance point. Furthermore, the iliac aneurysms of the groups displayed similar shrinkage 1 year after procedures.

CONCLUSIONS

For iliac aneurysm, the novel custom-made iliac bifurcation device is an adaptable design not inferior to commercial devices with regard to postoperative complications, bridge occlusion, endoleak and short-term aneurysm remodelling. It provides an alternative for treatment, particularly when certain anatomic challenges are present.

CLINICAL TRIAL REGISTRATION

2018-07-050BC, 2017-01-023ACF.

Clinical Significance of Ventricular Tachyarrhythmias in Patients Undergoing Valve Replacement: A Nationwide Population-Based Study

Background: The clinical significance and outcomes of ventricular tachyarrhythmias (VTa) in patients undergoing valve replacement have rarely been reported.

Objective: This study aimed to investigate the incidence and outcome of VTa after surgical valve replacement.

Methods: We conducted a population-based retrospective cohort study using data obtained from the Taiwan National Health Insurance Research Database. In total, 10,212 patients were selected after 1:1 propensity-score matching based on the type of prosthetic valve used (mechanical vs. bioprosthetic). Various outcomes during long-term follow-up were analyzed.

Results: After a median follow-up period of 59.6 months, the crude incidence rate of VTa after surgical valve replacement was 4.8/1,000 person-years, and the cumulative incidence of VTa persistently increased after surgery. Furthermore, the occurrences of VTa after valve replacement significantly increased the risk of cardiovascular (CV) death (P < 0.001, HR 1.67, 95% CI 1.41–1.96), stroke- (P < 0.001, HR 1.66, 95% CI 1.37–2.01), atrial fibrillation- (P < 0.001, HR 2.80, 95% CI 2.42–3.24), and congestive heart failure-related hospitalization (P < 0.001, HR 2.61, 95% CI 2.30–2.95). Among patients with VTa, all-cause mortality (P = 0.001, HR 0.49, 95% CI 0.32–0.75) and CV death (P = 0.047, HR 0.58, 95% CI 0.34–0.99) in those with implantable cardioverter-defibrillator (ICD) implantation were lower than those without.

Conclusion: The crude incidence rate of VTa after surgical valve replacement was 4.8/1,000 person-years, and the cumulative incidence of VTa persistently increased during follow-up. The presence of VTa after surgical valve replacement increases hospitalization and CV death, while ICD implantation reduced the mortality rate in these patients.

Betulinic Acid Affects the Energy-Related Proteomic Profiling in Pancreatic Ductal Adenocarcinoma Cells

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease with a 5-year survival rate of <8%. Therefore, finding new treatment strategies against PDAC cells is an imperative issue. Betulinic acid (BA), a plant-derived natural compound, has shown great potential to combat cancer owing to its versatile physiological functions. In this study, we observed the impacts of BA on the cell viability and migratory ability of PDAC cell lines, and screened differentially expressed proteins (DEPs) by an LC-MS/MS-based proteomics analysis. Our results showed that BA significantly inhibited the viability and migratory ability of PDAC cells under a relatively low dosage without affecting normal pancreatic cells. Moreover, a functional analysis revealed that BA-induced downregulation of protein clusters that participate in mitochondrial complex 1 activity and oxidative phosphorylation, which was related to decreased expressions of RNA polymerase mitochondrial (POLRMT) and translational activator of cytochrome c oxidase (TACO1), suggesting that the influence on mitochondrial function explains the effect of BA on PDAC cell growth and migration. In addition, BA also dramatically increased Apolipoprotein A1 (APOA1) expression and decreased NLR family CARD domain-containing protein 4 (NLRC4) expression, which may be involved in the dampening of PDAC migration. Notably, altered expression patterns of APOA1 and NLRC4 indicated a favorable clinical prognosis of PDAC. Based on these findings, we identified potential proteins and pathways regulated by BA from a proteomics perspective, which provides a therapeutic window for PDAC.

Correction to "Melissa officinalis Extract Induces Apoptosis and Inhibits Migration in Human Colorectal Cancer Cells"

[This corrects the article DOI: 10.1021/acsomega.0c04489.].

Mid-Term Outcome of Infected Abdominal Aortic Stent Graft Dismantlement with Reconstruction of Bilateral Axillofemoral Bypass

Background: Abdominal aortic stent graft infection (AAGI) is a severe complication. The optimal management of AAGI remains unclear. This study provides updated results of bilateral axillofemoral bypasses (AFBs) for patients with AAGI. Patients and Methods: In total, 31 patients (25 men; mean age, 67.1 years) with AAGI treated using AFB between January 2006 and April 2020 were included. Overall, the mean follow-up duration was 24 months (range, 1-72). In the 23 patients who survived the post-operative period, the mean follow-up duration was 32 months (range, 12-72). Results: Thirty-day and in-hospital mortality rates was 16% and 26%, respectively. The 12-month primary and secondary patency rates for the AFB graft were both 91%. In total, seven (30%) patients received re-interventions such as thrombectomy and balloon angioplasty. No amputation was required during follow-up. Culture results were positive in 87% of pre-operative cultures and 84% of intra-operative cultures. Staphylococcus aureus was the most prevalent pathogen, with four cases of methicillin-resistant Staphylococcus aureus and one each of vancomycin-resistant enterococci, carbapenem-resistant Klebsiella pneumoniae, and carbapenem-resistant Enterobacteriaceae. In-hospital mortality rate was 57% in patients with drug-resistant pathogens. Conclusions: Reconstruction with bilateral AFB and stent graft removal in patients with AAGI is a feasible treatment modality and provided an acceptable patency rate and low amputation rate. Additional studies investigating long-term results and the optimal treatment of AAGI are required.

Melissa officinalis Extract Induces Apoptosis and Inhibits Migration in Human Colorectal Cancer Cells

Colorectal cancer (CRC) is one of the most frequently diagnosed cancers worldwide. Lifestyle-related factors, such as diet, are associated with the development of CRC. Cumulating evidence indicates noticeable chemopreventive effects of phytochemicals on CRC, suggesting that drinking herbal tea potentially reduces the risk of distal colon cancer via its antiproliferative and anti-angiogenic activities. We examine the antitumor effects of nine components frequently found in herbal tea and uncover the underlying molecular mechanism. Among them, the hot water extract of Melissa officinalis (MO) exhibited the highest anticancer activity on CRC cells. We revealed that MO reduced cell proliferation, induced cell cycle arrest at the G₂/M phase, triggered caspase-dependent apoptotic cell death, and inhibited cell migration ability by modulating the epithelial-mesenchymal transition in HCT116 CRC cells. To examine the metabolite composition in the MO hot water extract, we applied mass spectrometry-based analysis and identified 67 compounds. Among them, the phenolic compounds, including lignans, phenylpropanoids, and polyketides, are widely found in natural products and possess various bioactivities such as anti-inflammatory, antioxidation, and anticancer effects. The results indicate that herbal tea consumption benefits CRC prevention and management.

Internal iliac artery preservation outcomes of endovascular aortic repair for common iliac aneurysm: iliac branch device versus crossover chimney technique

OBJECTIVES

To compare the outcomes of using iliac branch devices (IBD) and the crossover chimney (COCh) technique for preserving the internal iliac artery (IIA) during endovascular aortic repair in patients with common iliac aneurysm (CIA).

METHODS

From February 2010 to July 2016, we recruited 61 consecutive and elective patients. Thirty of them received the IBD, and the remaining 31 received the COCh. Their medical chart was reviewed retrospectively, and computed tomographic angiography was performed at 3, 6, and 12 months postoperatively and then yearly as a follow-up.

RESULTS

The median follow-up time was 19.72 ± 5.45 months. The technical success rate reached 100% in both groups. The 12-month and 24-month primary IIA patency rates between IBD and COCh group were 90.00% versus 93.54% (p = 0.67) and 83.33% versus 93.54% (p = 0.25). The numbers of stents were 1.00 ± 0.00 and 1.93 ± 0.24 in the IBD and COCh group (p < 0.001). No significant difference was observed for the incidence of type 1a (IBD/COCh = 3.33%/6.45%, p > 0.99) and type 2 endoleak (IBD/COCh = 13.33%/12.90%, p > 0.99) between two groups. Neither type 1b or type 3 endoleak nor delayed aortic rupture appeared in our series. The postoperative complication rates did not exhibit significant differences either. Free from reintervention was also similar in both groups (IBD/COCh = 22.50 ± 4.62/23.00 ± 3.87 months, p = 0.64).

CONCLUSIONS

The IBD and COCh techniques exhibited similar success rates and IIA patency rates at the 24-month follow-up. Both these techniques are feasible for the preservation of IIA in patients with CIA.

Tailor-made iliac branched device for preserving the internal iliac artery in patients with common iliac artery aneurysm

BACKGROUND

Endovascular repair with stent-graft is a treatment option for patient with common iliac artery aneurysm (CIAA). However, the preservation of the internal iliac artery (IIA) is a concern. The commercially available iliac branched device (IBD) requires a common iliac length of at least 5 cm, which is usually too long for Asian people. Here, we report our medium-term results of using tailor-made IBD for patients with short common iliac artery (CIA) with and without abdominal aortic aneurysm (AAA).

METHODS

A selected iliac limb of the AAA stent-graft was unloaded from the delivery system. A 6-mm fenestration hole was made at the length of the CIA from the proximal end. The edge of the hole was reinforced with the soft and radiopaque tip of a 0.014´´ wire. Then, the iliac limb was reloaded into the introduced sheath as the tailor-made IBD. It was inserted from the selected side of the femoral artery and deployed. The ipsilateral IIA was cannulated through the fenestration hole. Then, a balloon-expandable or self-expandable covered stent with an appropriate size was deployed as the bridging stent-graft.

RESULTS

Between March 2013 and March 2017, a total of 10 patients received the tailor-made IBDs. One patient died of systemic thromboembolism 2 days after the operation. The bridging stent-grafts remained patent in all patients, except one occluded at 1 year after operation.

CONCLUSION

A tailor-made IBD is an easy-to-apply, alternative option for preserving the IIA perfusion in short CIAA patients with and without AAA.

Impact of Renal Artery Stent-Graft Placement on Renal Function in Chronic Aortic Dissection

PURPOSE

To evaluate the effect of renal stent-graft placement on kidney function and size alternation in chronic aortic dissection.

MATERIALS AND METHODS

Twenty-five consecutive patients with chronic aortic dissection after thoracic endovascular aortic repair who underwent renal stent-graft placement between January 2015 and December 2016 were retrospectively reviewed. Forty-three patients with chronic aortic dissection who received thoracic endovascular aortic repair in the same period were reviewed as a control group for kidney volume comparison.

RESULTS

Twenty-five stent-grafts were deployed over 25 renal arteries. Overall renal function was assessed by the slope of the regression line constructed from the plots of creatinine clearance versus time within 2 years after the procedure (-0.2810 vs -0.3146 mL/min^-1/mo^-1, P = .868), kidney volume at 12 months (129.4 ± 40.9 vs 137.0 ± 44.2 cm², P = .193) and effective renal plasma flow at 6 months (106.3 ± 46.9 vs 124.4 ± 55.5 mL/min, P = .050) and was not significantly deteriorated. Seven treated patients (87.5%) with a renal artery supplied by a false lumen had a decrease in kidney volume, as did 14 patients (56%) in the control group (P = .206). Three patients with a dissected renal artery (75%) in the stent-graft group had an increase in kidney volume compared with 1 patient (11.1%) in the control group (P = .052).

CONCLUSIONS

Occlusion of the re-entry tear by a stent-graft in the renal artery remains a safe strategy to promote false lumen thrombosis. The stent-graft poses a potential risk of reducing the kidney volume in kidneys supplied by the false lumen but may provide a positive effect in kidney volume with a concomitant dissected renal artery in chronic aortic dissection.

Periorbital erythema and swelling as a presenting sign of lupus erythematosus in tertiary referral centers and literature review

Background Cutaneous lupus erythematosus (CLE) includes a broad range of dermatologic manifestations. Periorbital involvement, however, is a relatively rare clinical presentation of CLE. Objectives This clinical study aimed to investigate the characteristics of this unique presentation of CLE in tertiary medical centers. Methods We enrolled patients with periorbital erythema and swelling as the presenting sign of lupus erythematosus, from January 2003 to November 2017, using the data of 553 pathologically proven CLE cases from the registration database of the Chang Gung Memorial Hospitals in Taiwan. Results We enrolled a total of 25 patients. The mean age was 46.7 years and 68% of the patients were female. Most of the patients (84.0%) presented with unilateral involvement, with the left orbit involved in 15 patients (60%); the upper eyelid was the most frequently involved (72%). Mean duration between the onset of clinical manifestations and the diagnosis of CLE was approximately 59 weeks. Nineteen patients had been previously misdiagnosed. All patients had features compatible with CLE on histopathological examination. In contrast, laboratory analysis of the autoimmune profile often revealed negative results, including those for antinuclear antibodies (25%). Notably, anti-SSA/SSB (45.5%) showed the highest positive rate. During follow-up, six patients developed systemic lupus erythematosus (SLE) and two patients developed Sjögren syndrome. Conclusions The diagnosis of CLE presenting as periorbital erythema and swelling is often delayed because of clinical mimicry and the high proportion of negative results on autoantibody tests. Increased clinical suspicion and prompt histopathological examination are crucial for early diagnosis. Moreover, one-fourth of the patients ultimately developed SLE, which highlights the importance of clinical awareness.

One-stage surgery for removal of intravascular leiomyomatosis extending to right ventricle

RATIONALE

Intravascular leiomyomatosis (IVL) is a rare nonmalignant tumor that can be fatal if untreated.

PATIENT CONCERNS

A 49-year-old nulliparous Asian woman who underwent hysterectomy and left salpingo-oophorectomy for multiple uterine leiomyomas 18 months prior presented complaining of intermittent palpitation and chest tightness for approximately 1 month. Echocardiography revealed a large mobile tumor mass extending from the inferior vena cava (IVC) to the right atrium that partially obstructed IVC flow and tricuspid inflow. Thoracicabdominopelvic computed tomography revealed a left adnexal tumor (4.8 × 2.5 cm) causing intravascular obstruction extending from the left internal iliac vein to the IVC, right atrium, and right ventricle.

DIAGNOSIS

IVL with right heart involvement INTERVENTIONS:: Under cardiopulmonary bypass, a one-stage surgery combining sternotomy and laparotomy was performed. The tumor was approached and extracted via sternotomy, and tumor detachment and removal of residual tumors was accomplished via laparotomy.

OUTCOMES

A firm, smooth, and regularly shape tumor 15.5 × 5.5 × 2.5 in size was completely removed and histopathologically confirmed as IVL. The patient tolerated the surgical procedure well and no postoperative complication was noted.

LESSONS

We describe a one-stage surgical approach to completely remove an IVL extending to the right ventricle.

Cost-utility analysis of direct ventricular assist device vs double bridges to heart transplantation in patients with refractory heart failure

OBJECT

This study compared the cost-utility of direct ventricular assist device (VAD) vs double bridges, extracorporeal membrane oxygenation (ECMO) before VAD, to heart transplantation in patients with refractory heart failure.

MATERIALS AND METHODS

From a health payer perspective, a Markov model was developed. The cycle length was 1 month, and the time horizon was a lifetime. Probabilities and direct cost data were calculated from a nationwide claim database. Utility inputs were adopted from published sources. The utility was expressed as quality-adjusted life years (QALYs). Both costs and utility were discounted by an annual rate of 3%. Deterministic and probabilistic sensitivity analyses were performed to test the stability of the model.

RESULTS

The direct VAD group had less lifetime costs (USD 95 910 vs USD 129 516) but higher lifetime QALYs than the double bridges group (1.73 vs 0.89). The sensitivity analysis revealed that the direct VAD group consistently had lower cost and higher QALYs during all variations in model parameters. The probability that direct VAD was cost-effective exceeded 75% at any levels of willing-to-pay.

CONCLUSION

From a health insurance payer perspective, direct VAD bridge to heart transplantation appeared to be more cost-effective than double bridges in patients with refractory heart failure.

Overexpression of miR-194 Reverses HMGA2-driven Signatures in Colorectal Cancer

Colorectal cancer (CRC) is one of the leading causes of cancer death worldwide with increasing incidence and mortality in developed countries. Oncogenes and microRNAs regulate key signaling pathways in CRC and are known to be deregulated. Oncogenic transcriptional regulator high-mobility group AT-hook 2 (HMGA2) participates in the transformation of several cancers including CRC and exhibits strong correlation with poor prognosis and distal metastasis. Evidence of HMGA2 and its co-regulated miRs contributing to tumor progression remains to be clarified.

METHODS

We performed gene-set enrichment analysis on the expression profiles of 70 CRC patients and revealed HMGA2 correlated genes that are targeted by several miRs including miR-194. To eliminate the oncogenic effects in HMGA2-driven CRC, we re-expressed miR-194 and found that miR-194 functions as a tumor suppressor by reducing cell proliferation and tumor growth in vitro and in vivo.

RESULTS

As a direct upstream inhibitory regulator of miR-194, overexpression of HMGA2 reduced miR-194 expression and biological activity, whereas re-expressing miR-194 in cells with high levels of HMGA2 impaired the effects of HMGA2, compromising cell survival, the epithelial-mesenchymal transition process, and drug resistance.

CONCLUSION

Our findings demonstrate that novel molecular correlations can be discovered by revisiting transcriptome profiles. We uncover that miR-194 is as important as HMGA2, and both coordinately regulate the oncogenesis of CRC with inverted behaviors, revealing alternative molecular therapeutics for CRC patients with high HMGA2 expression.

Endovascular stenting for end-stage lung cancer patients with superior vena cava syndrome post first-line treatments - A single-center experience and literature review

BACKGROUND

Superior vena cava (SVC) syndrome is a major complication that occurs when a growing lung malignancy compresses the SVC extrinsically. Current treatment options include radiotherapy or chemotherapy to shrink the tumor or endovascular stenting of the SVC to restore flow. Herein, we report a case series treated in a single institution to demonstrate the safety, effectiveness, and outcomes of salvage and primary stenting for malignant SVC obstruction.

METHODS

A total of 12 male patients with malignant superior vena cava obstruction caused by lung cancer underwent SVC stenting from October 2009 to May 2015. Data were reviewed retrospectively, including demographic and clinical characteristics, procedural details, and outcomes.

RESULTS

Seven patients had received radiotherapy prior to SVC stenting, while the other five patients received stenting as first-line therapy for SVC syndrome. Only one patient experienced initial symptomatic improvement after radiotherapy, and symptoms of SVC syndrome recurred one year later. Wallstents^® (Boston Scientific, Natick MA, USA) were used in all patients. Preoperatively, the mean narrowest SVC diameter measured by CT was 2.16 mm (0-5.5 mm). Technical success was achieved in all patients without complications such as pulmonary embolism, rupture or bleeding. Postoperative mean narrowest SVC diameter measured by CT during follow-up was 11.17 mm (8-13.5 mm). Symptoms of SVC syndrome such as arm and face swelling and dyspnea improved within 1-5 days in all patients. After median follow-up duration of 11.5 months, only one patient presented recurrent SVC syndrome due to in-stent thrombosis two months after stenting.

CONCLUSION

Salvage SVC stenting remains a safe and effective treatment for patients with SVC obstruction after failure of radiotherapy and chemotherapy. Primary stenting may be considered at initial presentation of SVC syndrome to improve patients' quality of life.

Catheter-directed thrombolysis and pharmacomechanical thrombectomy improve midterm outcome in acute iliofemoral deep vein thrombosis

BACKGROUND

Aggressive and early thrombus removal strategy has been widely used as a treatment for iliofemoral deep vein thrombosis (DVT). We compared the long-tem venous outcome, including postthrombotic syndrome (PTS), in patients undergoing catheter-directed thrombolysis (CDT) and pharmacomechanical thrombectomy (PMT).

METHODS

From January 2009 to December 2013, 61 patients with acute proximal DVT were enrolled in this prospective study. Thirty-one patients underwent CDT and 30 patients underwent PMT, and each patient was followed for at least 2 years after treatment. Observations included venous outflow resistance, venous insufficiency, thrombus score (TS), severity of PTS, and surgical complications.

RESULTS

Venous outflow obstruction was similar in the CDT and PMT groups (32.3% vs. 30.0%, p = 0.695), and venous insufficiency of each group was 38.7% and 30.0% (p = 0.774), respectively. The TS at 24 months of each group showed no significant difference (0.90 vs. 0.70, p = 0.526). The mean Villalta scale scores of the CDT and PMT groups were 3.13 and 1.87, respectively (p = 0.042). Patients without PTS had significantly lower TS since 1 week postoperatively (1.59 vs. 4.60, p < 0.001). The severity of PTS was highly correlated with the TS, rate of thrombolysis, and severity of obstruction, and was moderately correlated with the venous registry index and reflux severity.

CONCLUSION

CDT and PMT have similar venous outcomes in patients with acute iliofemoral DVT, although PTS is less severe following PMT than after CDT. We propose that early and thorough removal of thrombus, using either CDT or PMT, is beneficial to prevent PTS.

Endovascular stenting for nutcracker syndrome

Nutcracker syndrome (NCS) is a rare pathology manifested by pain or hematuria in males and females alike. It can be easily overlooked, and should be considered in young men or women with symptoms of extended duration. We present a case of a 54-year-old female with chronic lower abdominal pain radiating to the left thigh of 4 years in duration. Computed tomography (CT) eventually revealed engorged left renal, gonadal, and uterine veins due to compression between the superior mesenteric artery (SMA) and the abdominal aorta, consistent with NCS. After a successful endovascular stenting and a 6-month period of antiplatelet and anticoagulant therapy, the patient returned to stable health. NCS, while rare, should be suspected in patients of both sexes with persistent pain or hematuria.

Neolysogenization of Xanthomonas campestris pv. citri infected with filamentous phage Cf16

All previously described filamentous bacteriophages are capable of persistent infection while their DNA replicates as an episome in the host cell. Filamentous phage Cf16 undergoes an infectious cycle different from other filamentous phages reported heretofore. Upon initial infection with Cf16, infective centers are formed, each of which produces a large number of phage particles. As the infectious cycle progresses, the phage particles released and infective centers formed per carrier cell decrease with time. Finally, the Cf16 enters a "prophage" state, in which the carrier cell becomes lysogenic containing only one complete phage genome in an integrated form. One out of 10(3)-10(6) lysogenic cells can develop spontaneously into an infective center, which releases only one to two phage particles per cell in stationary phase culture. After infection, the Cf16 genome integrates into the host chromosome and replicates as a part of it. Free RF (replicative form) coexists with the integrated form and replicates independently from host chromosome. Upon further division, carrier cells eliminate the free RF at each succeeding generation. When Cf16 reaches the "prophage" state, only the integrated phage genome remains in the carrier cell with no detectable free RF.

The lysogenic cycle of the filamentous phage Cflt from Xanthomonas campestris pv. citri

A phage, Cflt, forming turbid plaques, was isolated from Xanthomonas campestris pv. citri. After infection, infected sensitive cells become immune to Cflt and produce very few phages. These properties were genetically rather stable. The phage was purified and shown to be filamentous with a size of 1157 +/- 73 nm. The genome size is about 7.62 kb. The phage does not affect the growth of host bacteria. Under natural cultivation conditions Cflt-lysogenized cells could be induced spontaneously to give high phage yields, or cured to give phage-free cells. The integration of Cflt DNA into host DNA was proved by Southern blot hybridization. The lysogenic phage was genetically stable in log phase cells and persisted in stationary phase cells through many cell generations in the absence of extracellular phage reinfection.

Intraductal papillary neoplasia of the liver associated with hepatolithiasis

Intraductal papillary growth of neoplastic biliary epithelia with a fine fibrovascular stalk (intraductal papillary neoplasia of liver [IPN-L]) resembling intraductal papillary mucinous neoplasm of pancreas is occasionally associated with hepatolithiasis. In this study, 136 cases of hepatolithiasis in Taiwan, between January 1998 and March 2000, and an additional 21 cases of IPN-L before December 1998, were examined histologically. IPN-L was found in 41 of 136 hepatolithiasis cases (30.1%). Sixty-two IPN-L cases (42 women and 20 men; age range, 59.8 +/- 10 years) were divided into 4 types (type 1, IPN-L with low-grade dysplasia, 23 cases; type 2, IPN-L with high grade dysplasia, 11 cases; type 3, IPN-L with in situ and microinvasive carcinoma, 13 cases; and type 4, IPN-L of types 2 and 3 with distinct invasive carcinoma, 15 cases). Intraductal spreading and glandular involvement were commonly observed in all types. About half of types 3 and 4 cases had mucobilia, and mucinous carcinoma was variably found in two thirds of group 4 patients. IPN-L frequently showed variable gastroenteric differentiation such as goblet cells and foveolar and colon-like metaplasia. IPN-L with goblet cells and colon-like metaplasia was frequently associated with overproduction of mucin and mucobilia (P <.01). In Japan, IPN-L was not frequent in hepatolithiasis (12 of 135 cases). In conclusion, IPN-L forms a spectrum of biliary neoplasm in hepatolithiasis. It often displays variable gastroenteric metaplasia and significant intraductal spread. IPN-L tends to progress to mucinous carcinoma. Formerly reported "mucin-producing intrahepatic cholangiocarcinoma" with a favorable prognosis is included in IPN-L.

Classification of thymic epithelial neoplasms: a controversial issue coming to an end?

The classification of thymic epithelial neoplasms has been one of the most controversial issues in tumor pathology. There are two opposing schools of pathologists holding different views regarding the classification of thymic epithelial neoplasms. One school of pathologists believe that histological classification of thymomas is not possible or useful. Another school of pathologists believe that thymomas can be histologically subclassified despite their complex histomorphology and that these histological subtypes correlate with their aggressiveness and clinical behavior. A compromised histological classification has been established by World Health Organization (WHO) to designate thymic epithelial neoplasms with letters and numbers. This classification should be adopted internationally to facilitate the communication among concerned pathologists and oncologists. A simple histological classification of thymomas based on cytomorphology and supported by cytokeratin expressions is proposed and compared to the WHO and Müller-Hermelink's histogenetic classifications.

Specificity of the histopathological triad for the diagnosis of toxoplasmic lymphadenitis: polymerase chain reaction study

Toxoplasmosis is a common cause of lymphadenopathy, but toxoplasmic cysts are not usually found in histological sections used for establishing diagnosis, except on extremely rare occasions. The histopathological triad of florid reactive follicular hyperplasia, clusters of epithelioid histiocytes, and focal sinusoidal distention by monocytoid B cells has been considered to be diagnostic of toxoplasmic lymphadenitis, but the validity of the histopathological triad is based indirectly on serological correlation only. The demonstration of Toxoplasma gondii DNA in lymph nodes displaying the histopathological triad will indicate the validity of the histopathological triad as the criterion for the histopathological diagnosis of toxoplasmic lymphadenitis. We used frozen tissues of 12 lymph nodes with the histopathological triad and tissues of 27 lymph nodes from patients with various other conditions (including 13 cases of follicular lymphoid hyperplasia, FLH; three cases of dermatopathic lymphadenopathy, DPL; two cases of plasmacytosis; two cases of Castleman's disease; two cases of metastatic adenocarcinoma; and five cases of lymphoma) to detect T. gondii DNA by polymerase chain reaction. Ten out of 12 lymph nodes with the triad and six out of 27 lymph nodes without the triad were positive for T. gondii DNA. Thus, the sensitivity of the triad was 62.5% (10/16) and the specificity was 91.3% (21/23). The predictive value of positive tests was 83.3% (10/12) and the predictive value of negative tests was 77.7% (21/27). The six cases positive for T. gondii DNA without the triad were four cases of FLH, one case of DPL, and one case of plasmacytosis. None of the neoplastic diseases was positive. The false positive and negative cases could be due to sampling problems or past T. gondii infection. The results confirm that the histopathological triad is highly specific for the diagnosis of toxoplasmic lymphadenitis and can be used confidently.

Induction of a mitosis delay and cell lysis by high-level secretion of mouse alpha-amylase from Saccharomyces cerevisiae

Some foreign proteins are produced in yeast in a cell cycle-dependent manner, but the cause of the cell cycle dependency is unknown. In this study, we found that Saccharomyces cerevisiae cells secreting high levels of mouse alpha-amylase have elongated buds and are delayed in cell cycle completion in mitosis. The delayed cell mitosis suggests that critical events during exit from mitosis might be disturbed. We found that the activities of PP2A (protein phosphatase 2A) and MPF (maturation-promoting factor) were reduced in alpha-amylase-oversecreting cells and that these cells showed a reduced level of assembly checkpoint protein Cdc55, compared to the accumulation in wild-type cells. MPF inactivation is due to inhibitory phosphorylation on Cdc28, as a cdc28 mutant which lacks an inhibitory phosphorylation site on Cdc28 prevents MPF inactivation and prevents the defective bud morphology induced by overproduction of alpha-amylase. Our data also suggest that high levels of alpha-amylase may downregulate PPH22, leading to cell lysis. In conclusion, overproduction of heterologous alpha-amylase in S. cerevisiae results in a negative regulation of PP2A, which causes mitotic delay and leads to cell lysis.

UV-induced increase in RNA polymerase activity in Xanthomonas oryzae pathovar oryzae

UV radiation is thought to inhibit transcriptional elongation, as a result of the formation of pyrimidine dimers in the DNA template, as well as to activate specific transcription factors. However, the effect of UV radiation on the enzymatic activity of RNA polymerase has remained unknown. With the use of an in vitro assay, UV irradiation of Xanthomonas oryzae pathovar oryzae has now been shown to increase RNA polymerase activity. This effect was maximal at a UV dose of approximately 12 J m(-2) and at approximately 60 min after irradiation. It was also not inhibited by pretreatment of cells with chloramphenicol, an inhibitor of protein synthesis. Immunoprecipitation with antibodies to the RNA polymerase core enzyme revealed that exposure of the bacterial cells to UV radiation induced the association of the core enzyme with a protein of approximately 29 kDa. These results demonstrate that UV radiation increases the activity of RNA polymerase, and they suggest that this effect may be related to the repair of DNA damage.

Granulomatous variant of chronic pigmented purpuric dermatosis: report of two cases

Two patients presenting with chronic pigmented purpuric dermatosis (CPPD) on the dorsum of both feet were found to show granulomatous inflammation superimposed on the pathological changes of CPPD. Two similar cases have been reported from Japan. The unique clinicopathological features of this group of patients suggest that they have a rare granulomatous variant of CPPD.

Structural and functional characterization of the lexA gene of Xanthomonas campestris pathovar citri

The role of the LexA protein and, specifically, its effect on recA expression were analyzed in Xanthomonas campestris pathovar citri (X.c. pv. citri). Overexpression of LexA from X.c. pv. citri, in the plant pathogen, as well as in Escherichia coli, results in increased sensitivity to the DNA-damaging agents mitomycin C and ultraviolet radiation, indicating that the recombinant X.c. pv. citri LexA protein is functional in a different bacterial species. Immunoblot analysis revealed that the overexpressed LexA protein functioned as a repressor of recA expression in X.c. pv. citri, and that the mitomycin C-induced increase in the abundance of RecA was accompanied by specific proteolysis of LexA that required RecA. Although the LexA protein from X.c. pv. citri also blocked the expression of recA in E. coli, the E. coli RecA protein was not able to support the autocatalytic cleavage of LexA from the plant pathogen. The transcription start site of the X.c. pv. citri lexA gene was identified, and the region upstream of this gene was shown to confer responsiveness to mitomycin C on a luciferase reporter gene construct. Electrophoretic mobility-shift assays demonstrated that X.c. pv. citri LexA interacts with the promoter region of X.c. pv. citri lexA, as well as with those of the recA genes of X.c. pv. citri and E. coli. These results indicate that LexA functions as a repressor of gene expression in X.c. pv. citri just as it does in E. coli.

Characterization of a Saccharomyces cerevisiae mutant with oversecretion phenotype

An oversecreting mutant of Saccharomyces cerevisiae was obtained from about 400 meiotic segregants derived from thediploid cells made by crossing the HBsAg-induced mutant NI-C with the wild-type strain Sey6211. When transformed with a plasmid containing mouse alpha-amylase cDNA, the mutant (NI-C-D4) exhibited an increased capacity (up to 13-fold) for the secretion of mouse alpha-amylase, higher than the parental strains and other standard wild-type strains. It was also shown that alpha-amylase secreted by the oversecreting mutant had a higher activity and contained more of the non-glycosylated form than the glycosylated form. This isolated oversecreting, low-glycosylation mutant may prove to be a potential S. cerevisiae host for the production of foreign proteins. Further genetic analysis suggested that the mutation responsible for the mutant's oversecretion was partially dominant and that both the oversecretion and low-glycosylation phenotypes were governed by a single chromosome mutation. These pleiotrophic phenotypes may be attributed to a defect in the synthesis of an ER-resident chaperone.

Presence of Epstein-Barr virus latent membrane protein 1 gene in the nasopharyngeal swabs from patients with nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC) is the most common head and neck malignancy in southeastern China and Taiwan. Early detection of the local disease followed immediately by proper treatment is essential to increase the cure and survival rates. Because every NPC tumor cell carries Epstein-Barr Virus (EBV) genomes, detection of EBV genomic DNA such as latent membrane protein 1 gene (LMP1) might indicate the presence of NPC. We developed a simple and noninvasive technique of nasopharyngeal swabbing to acquire nasopharyngeal cells for detecting the presence of EBV genome. The aim of this study was to investigate the feasibility and reliability of this technique.

METHODS

We collected nasopharyngeal cells by means of a nasopharyngeal swabbing technique and detected the presence of EBV LMP1 with polymerase chain reaction (PCR). Thirty-eight swab specimens were obtained from patients with NPC who were newly diagnosed or were just beginning radiotherapy. Two groups of control subjects were recruited, including 20 patients with other head and neck cancers and eight family members of the NPC patients. An additional group of 65 NPC patients were enrolled in the course of regular follow-up after definitive radiotherapy.

RESULTS

All of the samples yielded sufficient DNA for PCR amplification. Thirty-six of 38 NPC swab samples were positive for EBV LMP1, and all the control subjects had swab sample results negative for EBV. All five patients with suspected local recurrence exhibited positive EBV test results.

CONCLUSIONS

Demonstration of EBV LMP1 in the nasopharyngeal swab specimens detected NPC with a sensitivity of 94.7% and specificity of 100%. This study confirms the reliability and feasibility of nasopharyngeal swab in the predicting and screening of NPC.

Reduction in mitochondrial respiratory capacity in Saccharomyces cerevisiae induced by expression of hepatitis B virus surface antigen

Transformants of Saccharomyces cerevisiae strain TL154 (MATalpha, trp1, leu2) expressing hepatitis B virus surface antigen showed reduced rates of cell growth compared with those of nontransformed cells. The rates of phosphorylative, nonphosphorylative, and uncoupled respiration in mitochondria isolated from the transformants were reduced relative to those of mitochondria derived from nontransformed cells, regardless of whether the cells were cultured in rich or minimal medium. The electrophoretic protein profiles of cell and mitochondrial extracts did not differ substantially between transformed and nontransformed cells. These results suggest that the reduced rate of mitochondrial respiration in the transformants may be due to impairment of metabolic function rather than to inhibition of the expression of components of the respiratory chain.

Pathologic studies of fatal cases in outbreak of hand, foot, and mouth disease, Taiwan

In 1998, an outbreak of enterovirus 71-associated hand, foot, and mouth disease occurred in Taiwan. Pathologic studies of two fatal cases with similar clinical features revealed two different causative agents, emphasizing the need for postmortem examinations and modern pathologic techniques in an outbreak investigation.

Acute encephalomyelitis during an outbreak of enterovirus type 71 infection in Taiwan: report of an autopsy case with pathologic, immunofluorescence, and molecular studies

We report a fatal case of enterovirus type 71 (EV 71) infection in an 8-year-old girl during a summer outbreak of hand, foot, and mouth disease in 1998 in Taiwan. The clinical course was rapidly progressive, with manifestations of hand, foot, and mouth disease, aseptic meningitis, encephalomyelitis, and pulmonary edema. The patient died 24 hours after admission. Postmortem study revealed extensive inflammation in the meninges and central nervous system and marked pulmonary edema with focal hemorrhage. Brain stem and spinal cord were most severely involved. The inflammatory infiltrates consisted largely of neutrophils involving primarily the gray matter with perivascular lymphocytic cuffing, and neuronophagia. The lungs and heart showed no evidence of inflammation. EV 71 was isolated from the fresh brain tissues and identified by immunofluorescence method with type-specific EV 71 monoclonal antibody. It was also confirmed by neutralization test and reverse-transcriptase polymerase chain reaction with sequence analysis. The present case was the first example in which EV 71 was demonstrated to be the causative agent of fatal encephalomyelitis during its epidemic in Taiwan.

Real-time PCR for quantitative detection of Toxoplasma gondii

The protozoan Toxoplasma gondii is one of the most common infectious pathogenic parasites and can cause severe medical complications in infants and immunocompromised individuals. We report here the development of a real-time PCR-based assay for the detection of T. gondii. Oligonucleotide primers and a fluorescence-labeled TaqMan probe were designed to amplify the T. gondii B1 gene. After 40 PCR cycles, the cycle threshold values (C(T)) indicative of the quantity of the target gene were determined. Typically, a C(T) of 25.09 was obtained with DNA from 500 tachyzoites of the T. gondii RH strain. The intra-assay coefficients of variation (CV) were 0.4, 0.16, 0.24, and 0.79% for the four sets of quadruplicate assays, with a mean interassay CV of 0.4%. These values indicate the reproducibility of this assay. Upon optimization of assay conditions, we were able to obtain a standard curve with a linear range (correlation coefficient = 0.9988) across at least 6 logs of DNA concentration. Hence, we were able to quantitatively detect as little as 0.05 T. gondii tachyzoite in an assay. When tested with 30 paraffin-embedded fetal tissue sections, 10 sections (33%) showed a C(T) of <40 and were scored as positive for this test. These results were consistent with those obtained through our nested-PCR control experiments. We have developed a rapid, sensitive, and quantitative real-time PCR for detection of T. gondii. The advantages of this technique for the diagnosis of toxoplasmosis in a clinical laboratory are discussed.

High-frequency interconversion of turbid and clear plaque strains of bacteriophage f1 and associated host cell death

Under normal cultivation conditions, a mixture of turbid and clear plaques is often apparent in cultures of bacterial cells infected with filamentous bacteriophages. Beginning with a culture of wild-type filamentous phage f1, which itself produces turbid plaques, a clear plaque strain (c1) was isolated. From c1, the turbid plaque strain t1 was isolated; from t1, the clear plaque strain c2 was isolated; and from c2, the turbid plaque strain t2 was isolated. Each of these strains was generated with a frequency of approximately 1 x 10(-4). Although filamentous phages have been thought not to induce host cell death, both turbid and clear plaque strains of f1 killed host bacteria. Plating of bacterial cells 1 h after infection revealed that colonies produced by cells infected with either wild-type f1 or strain c2 were smaller than those derived from uninfected cells, and that colony formation by infected cells was reduced by 15% and 38%, respectively. The time course of bacterial growth revealed that, at 4 h after infection, the number of CFU per milliliter of culture of cells infected with wild-type f1 or with strain c2 was reduced by 27% and 95%, respectively, compared with that for uninfected cells. Microculture analysis also revealed that the percentages of nondividing cells in f1 or c2 infected were 19% and 52%, respectively, 4 h after infection with wild-type f1 or with strain c2; no such cells were detected in cultures of uninfected cells. Negative staining and electron microscopy showed that 20% and 61% of cells infected with wild-type f1 or with strain c2 were dead 4 h postinfection. Finally, although the rates of DNA synthesis were similar for infected and uninfected cells, the rates of RNA and protein synthesis were markedly reduced in infected cells.

Frequent presence of neuroendocrine small cells in thymic carcinoma: a light microscopic and immunohistochemical study

AIMS

Neuroendocrine differentiation has been described in conventional carcinomas of various organs. Small cells postulated to be neuroendocrine cells were observed previously in some thymic carcinomas. This study was conducted to confirm and characterize the presence of neuroendocrine small cells in thymic carcinomas by light microscopy and immunohistochemistry.

METHODS AND RESULTS

Twenty-two thymic carcinomas were studied by light microscopy to detect the presence of small neuroendocrine-like cells. They were found in four of 10 squamous cell carcinomas (SCC) and seven of eight adenosquamous carcinomas (ASC). No small cells were observed in three lymphoepithelioma-like carcinomas (LELC) and one adenocarcinoma. The small cells were located within the tumour nests and constituted less than 1% of the entire tumour. In one case, small cells also extended outside the tumour nests. Rosette formation was seen in three cases. They were proved to be neuroendocrine cells by their immunoreactivity to neuron-specific enolase, chromogranin A, and/or synaptophysin. A few scattered neuroendocrine small cells were found only by immunohistochemistry in one case each of SCC, ASC, and LELC. The small cells were also strongly positive for cytokeratin (CK) 8 and CK18 but negative for CK19 and CK20. The predominant carcinoma cells other than the neuroendocrine small cells also displayed neuroendocrine markers in 68% of the cases studied.

CONCLUSIONS

Neuroendocrine small cells can be recognized by light microscopic examination in approximately 61% of thymic SCC and ASC. Neuroendocrine markers, CK8 and CK18 can aid in confirming their presence. The neuroendocrine small cells present in thymic carcinomas are different from the main carcinoma cells displaying immunohistochemical neuroendocrine markers. The presence of neuroendocrine small cells could be an useful marker for the differentiation of thymic carcinomas from thymomas and carcinomas of other sites.

p16INK4 gene mutation and allelic loss of chromosome 9p21-22 in Taiwanese hepatocellular carcinoma

BACKGROUND

The p16INK4 (MTS1/CDNK2A) gene, located on chromosome 9p21, is an inhibitor of cyclin-dependent kinase 4. Various data have shown that it is frequently inactivated in several types of cell lines and primary human cancers.

MATERIALS AND METHODS

Thirty cases with hepatocellular carcinoma were studied for possible p16INK4 gene mutation in Taiwan. Homozygous deletion was determined using polymerase chain reaction (PCR). The p16INK4 gene mutation was first screened by single strand conformation polymorphism, then direct DNA sequencing was performed on the cases with mobility shifts. Deletion mapping of chromosome 9p21-22 was also carried out with two polymorphic microsatellite markers (D9S925 and D9S168) using PCR.

RESULTS

One of the 30 cases had homozygous deletion at exon 3 of the p16INK4 gene. Another tumor had altered electrophoresed mobility in exon 2 with G to T transversion in the first nucleotide of codon 61 by direct sequencing causing a stop codon (GAG-->TAG). At the D9S925 and D9S168 loci, six out of 24 (25%) and three out of 19 (16%) informative cases showed loss of heterozygosity, respectively.

CONCLUSION

Point mutation and homozygous deletion of the p16INK4 gene are present in a subset of hepatocellular carcinomas in Taiwan. The patterns of the p16INK4 gene alteration are, however, different from those from other regions. In addition, allelic loss on chromosome 9p21-22 is not an uncommon event in hepatocellular carcinomas. Therefore, the significance of chromosome 9p loss deserves to be extensively investigated.

Generalized granuloma annulare associated with granulomatous mycosis fungoides

We describe a 68-year-old man with plaque stage mycosis fungoides (MF) for 8 years. He developed tumorous lesions of granulomatous MF (GrMF) and generalized granuloma annulare (GA) after a previously indolent clinical course. Since then, the clinical course was aggressive with involvement of the bone marrow and lymph nodes, and leukemic change occurred. Systemic chemotherapy was given, but the patient died 9 months later due to neutropenic fever and septic shock. GA in malignant lymphoma has been reported most frequently in association with Hodgkin's disease. To the best of our knowledge, GA associated with GrMF has never been reported in the English language literature. The prognostic significance of the association of granulomatous inflammation and malignancy is reviewed.

Asparagine as a nitrogen source for improving the secretion of mouse alpha-amylase in Saccharomyces cerevisiae protease A-deficient strains

A modified chemically defined medium was achieved by using asparagine as a nitrogen source to increase the production of secreted mouse alpha-amylase in several Saccharomyces cerevisiae protease A-deficient (pep4) strains. The specific productivity (quantity) and the 53 kDa non-glycosylated active form (quality) of mouse salivary alpha-amylase in liquid medium containing asparagine was remarkably improved compared to media containing other nitrogen sources, including ammonium sulphate, glutamic acid, arginine, casamino acids, yeast extract and peptone. Similar improvement was also observed on starch solid agar regarding the clarity and size of the halo zone formed by alpha-amylase activity. Compared with ammonium sulphate, advantages of using asparagine as the nitrogen source in liquid or solid medium included increasing the cell mass of test strains, recovering the viability of protease-deficient strains to levels similar to the wild-type strain, and increasing the copy number of the mouse alpha-amylase expression vector in test strains. In turn, these advantages apparently contributed to the increase of secretion of mouse alpha-amylase in several test strains and especially in the protease A-deficient strains. In addition to demonstrating the use of modified chemically defined medium to improve the quality and quantity of secreted mouse alpha-amylase, this study also provides a new strategy to improve the secretion of heterologous proteins in protease A deficient strains.

Requirement for phosphoglucose isomerase of Xanthomonas campestris in pathogenesis of citrus canker

A mutant (XT906) of Xanthomonas campestris pv. citri, the causal agent of citrus canker, was induced by insertion of the transposon Tn5tac1 and isolated. This mutant did not grow or elicit canker disease in citrus leaves but was still able to induce a hypersensitive response in a nonhost plant (the common bean). The mutant was also unable to grow on minimal medium containing fructose or glycerol as the sole carbon source. A 2.5-kb fragment of wild-type DNA that complemented the mutant phenotype of XT906 was isolated. Sequence analysis revealed that this DNA fragment encoded a protein of 562 amino acids that shows homology to phosphoglucose isomerase (PGI). Enzyme activity assay confirmed that the encoded protein possesses PGI activity. Analysis of the activity of the promoter of the pgi gene revealed that it was inhibited by growth in complex medium but induced by culture in plant extract. These results demonstrate that PGI is required for pathogenicity of X. campestris pv. citri.

The pilA gene of Xanthomonas campestris pv. citri is required for infection by the filamentous phage cf

Host factors that are important for infection of Xanthomonas campestris pv. citri by the filamentous bacteriophage cf were investigated by transposon mutagenesis with Tn5tac1. A mutant, XT501, that was resistant to cf infection was recovered, showing that the gene inactivated by the transposon is required for infection by the phage but not for cf replication or assembly. A 1.7-kb SacI-ApaI DNA fragment from XT501 containing the bacterial DNA flanking one end of the transposon was cloned and shown to be required for cf infection. Nucleotide sequence analysis of the 1.7-kb fragment reveals the presence of an ORF that encodes a protein of 146 amino acids. This protein shows 42% identity to the type 4 prepilin encoded by the pilA genes of other bacteria. The pilA gene of X. campestris pv. citri is thus essential for infection by the bacteriophage cf.

The primary immunity determinant in modulating the lysogenic immunity of the filamentous bacteriophage cf

Bacteriophage cf is the first single-stranded DNA phage that has been shown to set up a stable lysogenic state with its genome integrated into the host chromosome. From the isolation and characterization of a virulent mutant, cf-tv2, we report the first investigation into the mechanisms of the immunity established by the filamentous bacteriophage. The mutation in cf-tv2 enables the phage to produce plaques on lawns of cf lysogenic cells. The mutation was defined as a 49-nucleotide deletion located in a 0.59 kb NcoI/KpnI fragment of cf replicative form DNA. Two messages, cM1 and cM2, transcribed from the immunity region of wild-type cf but in opposite directions, were detected. In cf-tv2, the 49-nucleotide deletion abolishes cM2 transcription. The primer extension assay suggests a possible RNA-RNA interaction directed by base-pairing of the cM1 and cM2 RNAs. A frameshift mutation of the open reading frame ORF 165, encoded by cM2, resulted in a 10(5) plating efficiency on the cf lysogen. These observations suggest that both RNA-RNA interaction and repressor protein inhibition are involved in the mechanism of cf immunity. A model is proposed for the regulation of cf immunity.

Transcription of the genome of the filamentous bacteriophage cf from both plus and minus DNA strands

The filamentous bacteriophage cf infects the bacterium Xanthomonas campestris pv. citri. Northern blot analysis with probes derived from various restriction fragments of cf replicative form (RF) DNA has revealed the presence of five major phage-specific transcripts in infected cells. Four of these transcripts were shown to be derived from the region of the cf genome extending from gene II to gene VIII and are consistent with the cascade model of transcription proposed for Ff coliphages. These transcripts overlap with each other and terminate upstream of an efficient Rho-independent transcription terminator. Unlike the well-characterized Ff phages, in which only the minus strand of viral DNA serves as a transcription template, both strands of the RF DNA of phage cf appeared to be transcribed. Thus one of the five major cf transcripts was shown to be derived from a region of the viral minus strand that contains an open reading frame encoding a putative polypeptide of 165 amino acids. Primer extension analysis mapped the transcriptional initiation site of this RNA to a cytosine residue at position 870. A partial transcription map of phage cf revealed two independent regions of transcriptional activity. The region with the highest activity coincides with that encoding the polypeptides required in the largest amounts during the cf infection cycle.

A variant of Saccharomyces cerevisiae pep4 strain with improved oligotrophic proliferation, cell survival and heterologous secretion of alpha-amylase

A variant of Saccharomyces cerevisiae pep4 strain 20B12, with improved oligotrophic proliferation, cell survival and secretion of heterologous mouse alpha-amylase, is described. Previously we reported a procedure to enrich NI transformants that are not inhibited by cytotoxic expression of hepatitis B virus surface antigen in the secretion pathway of the protease-A-deficient (pep4) strain. To use the NI cells as a host for heterologous expression, we tried to amend the introduced pYAS/12S vector and obtain a host strain, NI-C, with stable NI phenotype and trp1 marker restored. Southern analysis of genomic DNA of NI-C suggested that the original pYAS/12S was abnormally rearranged and not completely corrected. Further assay showed that the viability and mitotic ability of the NI-C strain were increased. While using the NI-C strain as host for plasmid transformation and heterologous expression of mouse alpha-amylase, we observed that transformed colonies grew more quickly and secreted more alpha-amylase than general yeast strains. A further test showed that the NI-C strain was able to use mouse alpha-amylase as a positive selection marker to form transformed colonies on nitrogen-starved plates that contain starch as the sole carbon source. The results imply that the NI-C variant is an improved pep4 strain that can be used for heterologous expression and for the development of new selective markers in the yeast transformation system.