Regorafenib induces damage-associated molecular patterns, cancer cell death and immune modulatory effects in a murine triple negative breast cancer model

Damage associated molecular patterns (DAMPs), including calreticulin (CRT) exposure, high-mobility group box 1 protein (HMGB1) elevation, and ATP release, characterize immunogenic cell death (ICD) and may play a role in cancer immunotherapy. Triple negative breast cancer (TNBC) is an immunogenic subtype of breast cancer with higher lymphocyte infiltration. Here, we found that regorafenib, a multi-target angiokinase inhibitor previously known to suppress STAT3 signaling, induced DAMPs and cell death in TNBC cells. Regorafenib induced the expression of HMGB1 and CRT, and the release of ATP. Regorafenib-induced HMGB1 and CRT were attenuated following STAT3 overexpression. In a 4T1 syngeneic murine model, regorafenib treatment increased HMGB1 and CRT expression in xenografts, and effectively suppressed 4T1 tumor growth. Immunohistochemical staining revealed increased CD4⁺ and CD8⁺ tumor-infiltrating T cells in 4T1 xenografts following regorafenib treatment. Regorafenib treatment or programmed death-1 (PD-1) blockade using anti-PD-1 monoclonal antibody reduced lung metastasis of 4T1 cells in immunocompetent mice. While regorafenib increases the proportion of MHC II high expression on dendritic cells in mice with smaller tumors, the combination of regorafenib and PD-1 blockade did not show a synergistic effect on anti-tumor activity. These results suggest that regorafenib induces ICD and suppresses tumor progression in TNBC. It should be carefully evaluated when developing a combination therapy with an anti-PD-1 antibody and a STAT3 inhibitor.

Effectiveness of a childbirth massage programme for labour pain relief in nulliparous pregnant women at term: a randomised controlled trial

INTRODUCTION

The effect of massage for pain relief during labour has been controversial. This study investigated the efficacy of a programme combining intrapartum massage, controlled breathing, and visualisation for non-pharmacological pain relief during labour.

METHODS

This randomised controlled trial was conducted in two public hospitals in Hong Kong. Participants were healthy low-risk nulliparous Chinese women ≥18 years old whose partners were available to learn massage technique. Recruitment was performed at 32 to 36 weeks of gestation; women were randomised to attend a 2-hour childbirth massage class at 36 weeks of gestation or to receive usual care. The primary outcome variable was the intrapartum use of epidural analgesia or intramuscular pethidine injection.

RESULTS

In total, 233 and 246 women were randomised to the massage and control groups, respectively. The use of epidural analgesia or pethidine did not differ between the massage and control groups (12.0% vs 15.9%; P=0.226). Linear-by-linear analysis demonstrated a trend whereby fewer women used strong pharmacological pain relief in the massage group, and a greater proportion of women had analgesic-free labour (29.2% vs 21.5%; P=0.041). Cervical dilatation at the time of pethidine/epidural analgesia request was significantly greater in the massage group (3.8 ± 1.7 cm vs 2.3 ± 1.0 cm; P<0.001).

CONCLUSION

The use of a massage programme appeared to modulate pain perception in labouring women, such that fewer women requested epidural analgesia and a shift was observed towards the use of weaker pain relief modalities; in particular, more women in the massage group were analgesic-free during labour.

Kynurenine 3-monooxygenase upregulates pluripotent genes through β-catenin and promotes triple-negative breast cancer progression

Background

Triple-negative breast cancer (TNBC) is aggressive and has a poor prognosis. Kynurenine 3-monooxygenase (KMO), a crucial kynurenine metabolic enzyme, is involved in inflammation, immune response and tumorigenesis. We aimed to study the role of KMO in TNBC.

Methods

KMO alteration and expression data from public databases were analyzed. KMO expression levels in TNBC samples were analyzed using immunohistochemistry. Knockdown of KMO in TNBC cells was achieved by RNAi and CRISPR/Cas9. KMO functions were examined by MTT, colony-forming, transwell migration/invasion, and mammosphere assays. The molecular events were analyzed by cDNA microarrays, Western blot, quantitative real-time PCR and luciferase reporter assays. Tumor growth and metastasis were detected by orthotopic xenograft and tail vein metastasis mouse models, respectively.

Findings

KMO was amplified and associated with worse survival in breast cancer patients. KMO expression levels were higher in TNBC tumors compared to adjacent normal mammary tissues. In vitro ectopic KMO expression increased cell growth, colony and mammosphere formation, migration, invasion as well as mesenchymal marker expression levels in TNBC cells. In addition, KMO increased pluripotent gene expression levels and promoter activities in vitro. Mechanistically, KMO was associated with β-catenin and prevented β-catenin degradation, thereby enhancing the transcription of pluripotent genes. KMO knockdown suppressed tumor growth and the expression levels of β-catenin, CD44 and Nanog. Furthermore, mutant KMO (known with suppressed enzymatic activity) could still promote TNBC cell migration/invasion. Importantly, mice bearing CRISPR KMO-knockdown TNBC tumors showed decreased lung metastasis and prolonged survival.

Interpretation

KMO regulates pluripotent genes via β-catenin and plays an oncogenic role in TNBC progression.

Abstract 1711: Kynurenine 3-monooxygenase (KMO) acts as a novel oncoprotein in triple negative breast cancer

Purpose: Tryptophan-kynurenine pathway involves in inflammation, immune response and tumorigenesis, in which kynurenine 3-monooxygenase (KMO), an outer mitochondrial membrane protein, mediating kynurenine metabolism. Previous studies indicated KMO showed increased activity in breast cancer. Triple-negative breast cancer (TNBC) tumors exhibited elevated levels of tryptophan metabolites compared to estrogen receptor positive breast cancers. We aimed to study the role of KMO in human TNBC.

Experimental design: The gene alterations and transcripts of enzymes in kynurenine metabolism were analyzed from The Cancer Genome Atlas (TCGA) database. Immunohistochemical staining for KMO was performed and a H-score was assigned to quantify protein expression. Epithelial-mesenchymal transition (EMT) phenotypes were examined by transwell assay and EMT markers expressions. Stemness properties were assessed by mammosphere assay and pluripotent genes expressions. The molecular events were analyzed by Western blot, quantitative real-time PCR and luciferase reporter assay. Tumor growth and metastasis were conducted in nude mice and NOD-SCID mice by subcutaneous and tail vein injection respectively.

Results: TCGA databases showed KMO but not KYNU and KAT2 was amplified in breast cancer. Both the data from TCGA and our in-house IHC-based tissue-microarray exhibited increased KMO expression in TNBC compared to normal tissue. In vitro, overexpression of KMO in TNBC cells resulted in increased cell growth and colony formation. The abilities migration and invasion as well as EMT markers expressions of TNBC cells were elevated by KMO overexpression. In addition, KMO increased mammosphere formation, pluripotent genes expressions and promoter activities. However, inhibition of KMO enzymatic activity by KMO inhibitors did not affect cancer progression or mitochondrial respiration of TNBC cells. KMO upregulated β-catenin, the upstream regulator of pluripotent genes, CD44 and Nanog expressions. Mechanistically, data showed KMO expressed in both cytosol and nuclear fractions and was associated with β-catenin. KMO enhanced pluripotent genes expressions through β-catenin upregulation. Importantly, KMO knockdown suppressed tumor growth and expressions of β-catenin, CD44 and Nanog in TNBC tumors. Moreover, KMO knockout significantly decreased lung metastasis in vivo.

Conclusion: Our data indicated KMO can play an oncogenic role in TNBC, acting as a novel regulator of pluripotent genes via β-catenin and promoted TNBC progression.

Citation Format: Chun-Yu Liu, Tzu-Ting Huang, Ji-Lin Chen, Chia-Han Lee, Wan-Lun Wang, Ka-Yi Lau, Chun-Teng Huang, Pei-Yi Chu, Hsin-Chen Lee, Ling-Ming Tseng. Kynurenine 3-monooxygenase (KMO) acts as a novel oncoprotein in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1711.

Abstract 4372: SET/PP2A/SHP-1/Lyn oncogenic signaling contributes to tumor aggressiveness in diffuse large B cell lymphoma

Purpose:

Diffuse large B-cell lymphoma (DLBCL) is aggressive non-Hodgkin lymphoma. It is a heterogeneous disease and is classified as germinal center B-cell like (GCB) and activated B-cell like (ABC) subtypes according to gene-expression profiling. The oncogenic pathways in DLBCL are potential targets for new therapies. In present study, the role and regulation of SET/PP2A/SHP-1/Lyn axis in DLBCL were investigated.

Experimental design: U2932, OCL-Ly3, OCI-Ly7, SU-DHL-6 and DB DLBCL cell lines were used for this study. TD-19, a novel SET/PP2A protein-protein interaction inhibitor, was used to address the molecular events of SET signaling. Cell viability was measured by MTT assay. The apoptotic cells were examined by PI/Annexin V staining and Western blotting. SHP-1, Lyn and pLyn were analyzed by immunohistochemistry on lymphoma tissue microarrays from DLBCL patients.

Results:

We first examined the effects of two different SET inhibitors, TD-19 that is a SET/PP2A protein protein interaction inhibitor, and FTY720 which is a sphingosine analogue that targets SET, on DLBCL cells. TD-19 and FTY720 significantly decreased cell viability and induced apoptosis. SET inhibition activated PP2A and SHP-1 by reducing pPP2AY307 and pSHP-1S591 and inactivated Lyn by decreasing pLynY396. Overexpression of SET rescued these molecular events, and promoted cell growth and migration. Interestingly, we observed the level of SET was declined by TD-19 and TFY720 treatment. We hypothesized Lyn might up-regulate SET expression. Overexpression of Lyn increased SET level, and was accompanied with phosphorylation of PP2A (pPP2AY307) and SHP-1 (pSHP-1S591). Lyn elevated cell growth and migration and suppressed PP2A and SHP-1 activities. Moreover, exogenous SET restored the FTY720- and TD-19-suppressed pSHP-1 and pLyn. Immunohistochemically, high SHP-1 level was linked to low pLyn level of patient with DLBCL and vice versa.

Conclusion: This study established the existence of positive feedback of SET/PP2A/SHP-1/Lyn axis in DLBCL cells, and targeting SET could disrupt this regulation.

Citation Format: Ji-Lin Chen, Wen-Chun Tsai, Tien-Yun Lan, Chun-Teng Huang, Pei-Yi Chu, Chia-Han Lee, Ka-Yi Lau, Wan-Lun Wang, Kuen-Feng Chen, Chung-Wai Shiau, Chun-Yu Liu. SET/PP2A/SHP-1/Lyn oncogenic signaling contributes to tumor aggressiveness in diffuse large B cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4372.

Abstract 4612: SET overexpression is associated with recurrence-free survival in patients with primary breast cancer receiving adjuvant tamoxifen treatment

Background:

Estrogen receptor (ER) positive breast cancer accounts for 70% of breast cancer. Tamoxifen, a selective ER modulator, remains an important hormone therapeutic agent for patients with ER positive breast cancer. A number of patients receiving adjuvant tamoxifen still experience recurrence in the long term. In current study we explored the clinical significance of four biomarkers including SET, CIP2A, PP2A and Akt in ER positive breast cancer patients receiving adjuvant tamoxifen.

Methods:

Specimens were from ER positive breast cancer patients treated with adjuvant tamoxifen for a median of duration of 54.8 months with documented outcomes. The median follow-up was 106 months. Immunohistochemical staining for SET, CIP2A, p-PP2A (Tyr 307), p-Akt were performed and a H-score was assigned to quantify protein expression. In silico analysis of gene expression was evaluated from the public database KM plotter (available at: http://kmplot.com/analysis/). Human ER positive breast cancer cell line MCF7 cells were used for in vitro studies. MTT assay, flow cytometry and Western blot were used to assess the cells properties. Estrogen response element (ERE)-dependent luciferase activity was assessed by co-transfection of SET-expressing or control plasmids and 3⊆ERE bearing reporter plasmids into MCF7 cells and stimulated with estrogen.

Results:

In 218 primary ER positive breast cancer patients treated with adjuvant tamoxifen, 17 (7.8%) suffered from recurrence or metastasis. Higher expressions of SET and CIP2A by IHC analysis were associated with poor recurrence-free survival (RFS). Multivariate analysis revealed SET was independently correlated with worse RFS (Hazard ratio=3.72, 95% confidence interval 1.26-10.94, p=0.017). In silico, KM-plotter analysis revealed higher gene (mRNA) expressions of SET, PPP2CA and

Akt1 significantly correlated with worse RFS in breast cancer patients receiving adjuvant tamoxifen therapy. Because SET appeared to be the most prognostic for RFS among the four markers, we next explored the biological role in vitro. Tamoxifen exerted anti-proliferation and apoptotic effects in a dose-dependent manner of MCF7 cells. SET overexpression reduced tamoxifen-induced anti-proliferation in MCF-7 cells, in association with upregulated p-ER, suggesting that SET may affect ER pathway via the serine/threonine kinase PP2A. SET drove luciferase activity in an ERE-dependent manner, and also enhanced estrogen-promoted luciferase activity.

Conclusions:

Protein SET is a prognostic biomarker in ER positive breast cancer patients treated with tamoxifen and may contribute to tamoxifen resistance by modulating ER signaling pathway.

Citation Format: Yu-Hsiang Huang, Pei-Yi Chu, Ji-Lin Chen, Chun-Teng Huang, Chia-Han Lee, Ka-Yi Lau, Wan-Lun Wang, Yu-Ling Wang, Pei-Ju Lien, Ling-Ming Tseng, Chun-Yu Liu. SET overexpression is associated with recurrence-free survival in patients with primary breast cancer receiving adjuvant tamoxifen treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4612.

Dual-wavelength, mode-locked erbium-doped fiber laser employing a graphene/polymethyl-methacrylate saturable absorber

Mode-locked fiber laser incorporating a saturable absorber is an attractive configuration due to its stability and simple structure. In this work, we demonstrate a dual-wavelength passively mode-locked erbium-doped fiber laser employing a graphene/polymethyl-methacrylate saturable absorber. A laser resonator is developed based on dual cavity architecture with unidirectional signal oscillation, which is connected by a fiber branch sharing a common gain medium and saturable absorber. Dual wavelength mode-locked fiber lasers are observed at approximately 1530 and 1560 nm with 22.6 mW pump power threshold. Soliton pulse circulates in the laser cavity with pulse duration of 900 and 940 fs at shorter and longer wavelengths, respectively. This work presents a viable option in developing a low threshold mode-locked laser source with closely spaced dual wavelength femtosecond pulses in the C-band wavelength region.

Combination of palbociclib with enzalutamide shows in vitro activity in RB proficient and androgen receptor positive triple negative breast cancer cells

Objectives

Triple negative breast cancer (TNBC) lacks specific drug targets and remains challenging. Palbociclib, a cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitor is approved for metastatic estrogen receptor (ER)-positive and human epithermal growth factor 2 (HER2)-negative breast cancer. The nature of cell cycle inhibition by palbociclib suggests its potential in TNBC cells. Retinoblastoma (RB, a known substrate of CDK4/6) pathway deregulation is a frequent occurrence in TNBC and studies have revealed that pharmacological CDK4/6 inhibition induces a cooperative cytostatic effect with doxorubicin in RB-proficient TNBC models. In addition, recent studies reported that anti-androgen therapy shows preclinical efficacy in androgen-receptor (AR)-positive TNBC cells. Here we examined the effect of palbociclib in combination with an anti-androgen enzalutamide in TNBC cells.

Method

MDA-MB-453, BT-549, MDA-MB-231 and MDA-MB-468 TNBC cell lines were used for in vitro studies. Protein expressions were assessed by Western blot analysis. Cytostatic effect was examined by MTT assay. Cell cycle and apoptosis were examined by flow cytometry.

Results

Palbociclib showed inhibitory effect in RB-proficient TNBC cells, and enzalutamide inhibited cell viability in AR-positive TNBC cells. Enzalutamide treatment could enhance the palbociclib-induced cytostatic effect in AR-positive/RB-proficient TNBC cells. In addition, palbociclib-mediated G1 arrest in AR-positive/RB-proficient TNBC cells was attenuated by RB knockdown.

Conclusion

Our study provided a preclinical rationale in selecting patients who might have therapeutic benefit from combining CDK4/6 inhibitors with AR antagonists.

Abstract 4201: Combination of palbociclib with enzalutamide shows in vitro activity in RB-proficient and androgen receptor-positive triple-negative breast cancer cells

Background

Cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitors have in vitro synergistic effects and significant clinical efficacy in combination with hormone therapy for estrogen receptor (ER)-positive advanced breast cancer. However, the effects of CDK4/6 inhibitors in triple negative breast cancer (TNBC) are not well-elucidated. Retinoblastoma (RB, a known substrate of CDK4/6) protein pathway deregulation is a frequent occurrence in TNBC and in vitro studies have revealed that pharmacological CDK4/6 inhibition yields a cooperative cytostatic effect with doxorubicin in RB-proficient TNBC models, suggesting that RB may be a biomarker for selecting patients receiving CDK4/6 inhibitors. In addition, anti-androgen therapy have been shown preclinical efficacy in androgen-receptor (AR) positive TNBC cells. Here we tested the combination effect of a CDK4/6 inhibitor palbociclib with an AR antagonist enzalutamide in TNBC cells.

Methods

MDA-MB-231, MDA-MB-468 and MDA-MB-453 TNBC cell lines were used for in vitro studies. Cell viability was examined by MTT assay. Apoptotic effects were examined by flow cytometry. Signal transduction pathways in cells were assessed by Western blot.

Results

We correlated the expressions of AR and pRB status in these TNBC cells and identified that MDA-MB-453 were AR-positive/pRB-positive, MDA-MB-231 were AR-negative/pRB-positive, and MDA-MB-468 were AR-negative/pRB-negative cells. Since CDK4/6 inhibition leads to dephosphorylation of pRB, we examined effects of palbociclib and found that palbociclib significantly inhibited the cell growth of pRB-positive cell lines MDA-MB-453 and MDA-MB-231, but did not affect pRB-negative MDA-MB-468 cells. Further combining palbociclib with enzalutamide showed that the growth inhibitory effects of combination therapy were additive in AR-positive/pRB-positive MDA-MB-453 cells, but not in AR-negative/pRB-positive MDA-MB-231 cells, nor AR/pRB double negative MDA-MB-468 cells. Moreover, palbociclib-induced G1/S arrest only exhibited in pRB-proficient MDA-MB-453 and MDA-MB-231 cells. In contrast, enzalutamide did not affect the cell cycle on any of these TNBC cell lines but inhibited phosphorylation of AR signaling in AR-positive MDA-MB-453 cells. In addition, both palbociclib and enzalutamide induced little apoptosis, suggesting cytostatic effects of these agents.

Conclusions

In summary, both pRB and AR status are important for response of TNBC cells to palbociclib. Combination of palbociclib with enzalutamide shows more prominent cytostatic effects in RB proficient and AR positive TNBC cells, comparing to AR-negative/pRB-positive or AR/pRB double negative TNBC cells. Our data provide a preclinical rationale in selecting patients who might have therapeutic benefit from combining CDK4/6 inhibitors with AR antagonists.

Citation Format: Ling-Ming Tseng, Tzu-Ting Huang, Chun-Teng Huang, Ka-Yi Lau, Chun-Yu Liu, Chung-Wai Shiau, Kuen-Feng Chen. Combination of palbociclib with enzalutamide shows in vitro activity in RB-proficient and androgen receptor-positive triple-negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4201. doi:10.1158/1538-7445.AM2017-4201

Sequential combination of docetaxel with a SHP-1 agonist enhanced suppression of p-STAT3 signaling and apoptosis in triple negative breast cancer cells

Triple negative breast cancer (TNBC) is an aggressive cancer for which prognosis remains poor. Combination therapy is a promising strategy for enhancing treatment efficacy. Blockade of STAT3 signaling may enhance the response of cancer cells to conventional chemotherapeutic agents. Here we used a SHP-1 agonist SC-43 to dephosphorylate STAT3 thereby suppressing oncogenic STAT3 signaling and tested it in combination with docetaxel in TNBC cells. We first analyzed messenger RNA (mRNA) expression of SHP-1 gene (PTPN6) in a public TNBC dataset (TCGA) and found that higher SHP-1 mRNA expression is associated with better overall survival in TNBC patients. Sequential combination of docetaxel and SC-43 in vitro showed enhanced anti-proliferation and apoptosis associated with decreased p-STAT3 and decreased STAT3-downstream effector cyclin D1 in the TNBC cell lines MDA-MB-231, MDA-MB-468, and HCC-1937. Ectopic expression of STAT3 reduced the increased cytotoxicity induced by the combination therapy. In addition, this sequential combination showed enhanced SHP-1 activity compared to SC-43 alone. Furthermore, the combination treatment-induced apoptosis was attenuated by small interfering RNA (siRNA) against SHP-1 or by ectopic expression of SHP-1 mutants that caused SC-43 to lose its SHP-1 agonist capability. Moreover, combination of docetaxel and SC-43 showed enhanced tumor growth inhibition compared to single-agent therapy in mice bearing MDA-MB-231 tumor xenografts. Our results suggest that the novel SHP-1 agonist SC-43 enhanced docetaxel-induced cytotoxicity by SHP-1 dependent STAT3 inhibition in human triple negative breast cancer cells. TNBC patients with high SHP-1 expressions show better survival. Docetaxel combined with SC-43 enhances cell apoptosis and reduces p-STAT3. SHP-1 inhibition reduces the enhanced effect of docetaxel-SC-43 combination. Docetaxel-SC-43 combination suppresses xenograft tumor growth and reduces p-STAT3.

KEY MESSAGES

TNBC patients with high SHP-1 expressions show better survival. Docetaxel combined with SC-43 enhances cell apoptosis and reduces p-STAT3. SHP-1 inhibition reduces the enhanced effect of docetaxel-SC-43 combination. Docetaxel-SC-43 combination suppresses xenograft tumor growth and reduces p-STAT3.

Thoracic spinal gout mimicking metastasis

Gout is a common metabolic disease but spinal gout is rare. We report a case of gouty arthritis affecting the thoracic spine in a 76-year-old male patient with a long history of tophaceous gout who presented with bilateral lower limb weakness. Magnetic resonance imaging of his thoracic spine revealed erosions in the left pedicles of T8 and T10. The initial imaging diagnosis was metastatic disease. A computed tomography-guided biopsy of the T10 lesion was performed and confirmed the diagnosis of gout. We advocate the use of computed tomography-guided fine-needle aspiration/biopsy for diagnosing spinal gout because the imaging features are non-specific, metastasis and spondylodiscitis being important mimickers.

Emergency transcatheter embolisation of superior mesenteric arteriovenous fistula complicated by recurrent haematemesis

Arterioportal fistulas are rare. Superior mesenteric arteriovenous fistula is uncommon and usually observed in patients who have abdominal trauma or have undergone abdominal surgery. If untreated, mesenteric arteriovenous fistula is potentially fatal due to portal hypertension with potential complications such as massive variceal bleeding or progressive liver failure. We report a 50-year-old Chinese man who had a history of abdominal surgery and presented with recurrent haematemesis. He was diagnosed by multidetector computed tomography to have a superior mesenteric arteriovenous fistula. Subsequently, he presented with acute bleeding oesophageal varices. Emergency transarterial embolisation was successfully performed to arrest the bleeding.

Bilateral cervical spondylolysis in a young Chinese woman presenting with a neck injury

Cervical spondylolysis is an uncommon entity. It is important to recognise its characteristic radiological features and differentiate it from acute cervical fractures or dislocations in patients with neck injuries. We report the relevant clinical and radiological findings seen in a young Chinese woman managed in our hospital after a neck injury who was ultimately diagnosed with bilateral cervical spondylolysis with spondylolisthesis at C6.

Surveillance mammography after breast conservation therapy in Hong Kong: effectiveness and feasibility of risk-adapted approach

Annual surveillance mammography is commonly recommended after breast conservation therapy (BCT). We retrospectively reviewed its effectiveness on 511 invasive and non-invasive breast cancers treated with BCT between 1994 and 2003. The median follow-up was 5.9 years. The 5-year actuarial ipsilateral breast tumour recurrence (IBTR) rate was 4.5% and contralateral breast cancer (CBC) rate was 2.0% (representing eight times increase in risk). IBTR of 43% and 62% CBC were first detected by surveillance mammography. The IBTR detection rates per 1000 mammograms were 5.2 for patients (n=349) with one or more IBTR risk factors (age 45, positive/close margins or histological grade 3) and 0.6 for patients (n=162) without. No survival difference was observed between different modes of IBTR detection (p=0.342). In conclusion, a risk-adapted approach of limiting ipsilateral surveillance to patients with IBTR risk is possible but its implementation will be complicated by the continued need of contralateral surveillance.

Percutaneous replacement of a right jugular dialysis catheter via a stenosed superior vena cava

A female patient with end-stage renal failure, who was maintained on haemodialysis via multiple central dialysis catheters, developed chronic occlusion of the left brachiocephalic vein. Subsequently, the right jugular dual lumen PermCath became dysfunctional because of marked superior vena cava stenosis. Angioplasty of the superior vena cava stenosis was performed but failed to restore adequate catheter function. The patient was referred for possible salvage of her central venous access and re-insertion of a new PermCath. During surgery, the right jugular PermCath was removed, the superior vena cava was stented to establish venous patency, and a new PermCath was re-inserted via the existing right jugular puncture site. The technique helps reduce cost and time, and avoids another jugular puncture. In addition, this procedure saves a central venous access which is important in patients on long-term haemodialysis.

Transcatheter embolisation of visceral pseudoaneurysms--technical difficulties and modification of embolisation technique

We report 13 successful emergency embolisations for 12 pseudoaneurysms performed in 10 patients. For five pseudoaneurysms the embolisation technique was modified according to number of supplying vessels, flow rate of pseudoaneurysms, vascular anatomy and whether there was clinical evidence of re-bleeding or not. Apart from traditional embolisation technique, modified embolisation techniques are also useful for endovascular therapy of pseudoaneurysms.

Arterial embolisation in intractable primary post-partum haemorrhage: case series

OBJECTIVE

To evaluate the efficacy and safety of arterial embolisation in the management of intractable primary post-partum haemorrhage. DESIGN. Retrospective case series.

SETTING

Regional hospital, Hong Kong.

PATIENTS

Nine patients aged 28 to 39 years who were treated for severe primary post-partum haemorrhage between October 2000 and January 2003.

INTERVENTION

Emergency transcatheter arterial embolisation.

MAIN OUTCOME MEASURES

Clinical outcome and complications.

RESULTS

All nine arterial embolisations successfully arrested the haemorrhage. The main cause of primary post-partum haemorrhage was uterine atony. No serious complication arose, although one patient experienced slight numbness of the right leg. Normal menstruation resumed in all patients, except for the one who had had a hysterectomy as initial treatment. One patient became pregnant 1 year after embolisation. Patients were followed up for 10 months.

CONCLUSION

In our experience, arterial embolisation is safe and efficacious, and is the treatment of choice for patients with intractable primary post-partum haemorrhage.

Accuracy of nasopharyngeal carcinoma staging by magnetic resonance imaging

To audit the accuracy of magnetic resonance (MR) staging of nasopharyngeal carcinoma (NPC) in daily reporting, the MR images of 101 adult patients with newly diagnosed NPC reported between December 1996 and February 2002 were reviewed retrospectively. Based on the American Joint Committee on Cancer/International Union Against Cancer (AJCC/UICC) TNM staging criteria (1997), the tumour staging obtained from the MR reports and the MR films was compared by two experienced head and neck radiologists. The number of patients being upstaged, downstaged or unchanged was noted. In all stages, the NPC staging obtained from the MR reports revealed 18 (17.8%) understaged, eight (7.9%) overstaged and 75 (74.2%) the same stage when compared to the staging obtained from the MR films based on the AJCC/UICC criteria. The percentage of patients being understaged or overstaged, in decreasing order of frequency, were stages II, III, IV and I. Magnetic resonance of NPC should be reported by radiologists who are not only familiar with the pathology of this condition and its pattern of spread but who should also base their reports on the AICC/UICC staging criteria. The necessity to improve our MR staging accuracy is largely because it determines the type of therapy to be given and this has to be appropriate and adequate for a successful treatment.

High-resolution CT findings in patients with severe acute respiratory syndrome: a pattern-based approach

OBJECTIVE

We retrospectively reviewed high-resolution CT (HRCT) examinations of the lungs performed in 27 confirmed cases of severe acute respiratory syndrome (SARS). The HRCT findings at different phases of the illness were analyzed.

CONCLUSION

A defined pattern of HRCT findings is observed in different phases of SARS, which is characterized by focal ground-glass and crazy paving patterns in a scattered distribution at presentation, followed by development of interstitial thickening, consolidation, pleural reaction, and scarring. Spontaneous pneumomediastinum is a distinct complication during the course of the illness.

Emergency embolization of spontaneous ruptured hepatocellular carcinoma: correlation between survival and Child-Pugh classification

From February 1994 to April 2000, 29 emergency gelfoam embolizations for spontaneous ruptured hepatocellular carcinoma (HCC) performed in 28 patients were retrospectively reviewed. There were 11 patients in Child's A, 11 in Child's B and six in Child's C classification of cirrhosis. The duration of the procedure, artery embolized and complications were reviewed, and the Child-Pugh classification of each patient was correlated with their mean survival period. Embolization was done in 12 right hepatic arteries, two left hepatic arteries and 15 proper hepatic arteries. In one patient, the left hepatic artery was embolized initially but the proper hepatic artery was also embolized because another subcapsular liver tumour was found after reviewing the preangiogram CT scan. The entire procedure took 40-170 min (mean = 86 min) with no periprocedural complication. Following embolization, the mean survival period for Child's A class was 218.3 days, Child's B class was 83.4 days and Child's C class was 11.0 days. Transcatheter embolization is an effective treatment to arrest bleeding in spontaneous ruptured HCC. Patients with Child's A class cirrhosis have the longest survival. Selective embolization of either the right or the left hepatic artery alone carries the potential risk of missing multifocal HCC that might not be easily appreciated during angiography.

Brachiocephalic-superior vena cava metallic stenting in malignant superior vena cava obstruction

INTRODUCTION

We studied the effectiveness of unilateral brachiocephalic (BC)-superior vena cava (SVC) metallic stent therapy in malignant SVC obstruction.

MATERIALS AND METHODS

From November 1998 to February 2002, SVC stenting was performed in 11 patients with symptomatic malignant SVC obstruction. There were 10 males and 1 female, with a mean age of 64.2 years (range, 37 to 78 years). The computed tomography (CT) scan and superior vena cavogram findings of all patients showed malignant SVC obstruction. Both internal jugular veins were patent in all patients by ultrasound. SVC stenting was performed with Wallstent (Boston Scientific, Minneapolis, MN, USA) in 10 patients and Memotherm stent (Bard angiomed, Wachhausstrasse, Germany) in 1 patient. Pressure gradient, duration of the procedure, peri-procedural morbidity and mortality and the general well-being of the patients were reviewed.

RESULTS

SVC stenting was performed at a mean duration of 9.6 days (range, 3 to 30 days) after presentation. All were technically successful with 10 across the right BC-SVC and 1 across the left BC-SVC. There was no peri-procedural morbidity or mortality. The entire procedure was completed at a mean duration of 115 minutes (range, 75 to 225 minutes) with good angiographic and pressure results. Immediate symptomatic relief of SVC syndrome was achieved in 10 patients who had received prompt work-up and stenting 3 to 18 days after presentation. The remaining patient, who received work-up and stenting 30 days after presentation, remained dyspnoeic and died of pneumonia 7 days after the procedure.

CONCLUSION

Unilateral BC-SVC metallic stenting is an effective measure in malignant SVC obstruction. Prompt pre-stenting work-up and stenting are recommended to achieve a longer symptomatic relief period.

Venous thromboembolism in the Chinese population--experience in a regional hospital in Hong Kong

OBJECTIVE

To estimate the incidence and determine the characteristic features of venous thromboembolism in the Hong Kong Chinese population.

DESIGN

Retrospective study.

SETTING

Regional hospital, Hong Kong.

SUBJECTS AND METHODS

Data were collected during a period of four years (1997-2000). Patients with duplex doppler ultrasonography or venography-documented venous thromboembolism and new episodes of deep vein thrombosis were identified from Department of Diagnostic Radiology records. Patients with high-probability ventilation-perfusion scans were identified from Department of Nuclear Medicine records and these scans were taken as evidence of pulmonary embolism. Patients with intermediate-probability ventilation-perfusion scans, with pulmonary embolism documented by either pulmonary angiography or spiral computed tomography scan, were also included in the study. Patients with autopsy-verified fatal pulmonary embolism were identified from Department of Pathology records. Patients with deep vein thrombosis at other sites were sought from patient discharge diagnostic coding data. Medical records were reviewed for patient characteristics and conditions associated with the development of venous thromboembolism.

RESULTS

Three hundred and seventy-six Chinese patients had venous thromboembolism during the study period. Of these, 352 had peripheral deep vein thrombosis, five had deep vein thrombosis at other sites (cerebral sinus and portal vein thrombosis), 40 had pulmonary embolism (26 had concomitant deep vein thrombosis), and six had fatal pulmonary embolism shown at autopsy.

CONCLUSION

The calculated annual incidence of venous thromboembolism in Hong Kong Chinese people was estimated at 16.6 events per 100,000 population, which is lower than incidence rates reported in Caucasians. The four conditions most commonly associated with venous thromboembolism were medical illness, malignancy, orthopaedic surgery, and intravenous drug use. Conditions associated with venous thromboembolism in patients younger than 45 years included intravenous drug use, thrombophilia, pregnancy, and the use of oral contraceptives.

Embolisation of a renal artery pseudoaneurysm in a patient with renal malrotation and chronic aortic dissection

INTRODUCTION

Renal artery pseudoaneurysms may arise as a complication of percutaneous nephrolithotomy (PCNL). Prompt recognition and treatment is essential to arrest haemorrhage which may be life threatening.

CLINICAL PICTURE

A patient with chronic aortic dissection and malrotated right kidney underwent PCNL for right renal calculus. He developed delayed gross haematuria.

TREATMENT

Angiography showed a pseudoaneurysm arising from one of two right renal arteries, which in turn arose from the false lumen of the aortic dissection. The supplying artery was successfully embolised.

CONCLUSION

Renal artery pseudoaneurysms can be successfully treated with prompt angiography and embolisation, even in the presence of renal malrotation and aortic dissection.

MRI of the hypothalamus and pituitary gland in patients with hyperprolactinaemia following radiotherapy for nasopharyngeal carcinoma

PURPOSE

Neuroendocrine dysfunction is a known complication of cranial radiation. While growth hormone deficiency is the most common laboratory finding, hyperprolactinaemia is one of the most common symptomatic dysfunction in adult female patients with nasopharyngeal carcinoma (NPC) following radiotherapy. This analysis aims to study the magnetic resonance imaging (MRI) features of the hypothalamus and the pituitary gland in affected patients.

METHODS

MRI was performed in 24 patients NPC with hyperprolactinaemia detected 10-52 months following one course of radical radiotherapy. The region of study included the nasopharynx, the hypothalamus and the pituitary gland in 20 patients, while in the remaining four patients, this was limited to the pituitary gland. The estimated radiation dose to the hypothalamus and the pituitary gland was 66 Gy, and six patients also had adjuvant chemotherapy. There was no clinical evidence of tumour recurrence in all 24 patients when hyperprolactinaemia was detected.

RESULTS

None of the 24 patients showed any MRI evidence of structural abnormality in the hypothalamic-pituitary region.

CONCLUSION

MRI did not reveal any structural abnormality in the hypothalamic-pituitary region of patients who developed hyperprolactinaemia following radiotherapy for NPC.

Long-term cerebral metabolite changes on proton magnetic resonance spectroscopy in patients cured of acute lymphoblastic leukemia with previous intrathecal methotrexate and cranial irradiation prophylaxis

PURPOSE

To evaluate the long-term brain metabolite changes on (1)H-MRS in acute lymphoblastic leukemia (ALL) patients who had intrathecal methotrexate (ITMTX) and cranial irradiation (CRT) for central nervous system (CNS) prophylaxis against CNS relapse.

METHODS AND MATERIALS

Thirty-seven ALL patients (12 females, 25 males) with history of ITMTX and CRT for CNS prophylaxis were studied. Age ranges at the time of diagnosis and at magnetic resonance examination were 0.8-13 years and 12-27 years, respectively. The interval since diagnosis was 5.6-19 years. T2-weighted and gradient-recalled echo (GRE) magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy ((1)H-MRS) were performed to assess brain injury.

RESULTS

On MRI, 3 leukoencephalopathy (LEP) and 1 infarct were detected. Twenty-two patients had evidence of hemosiderin. On (1)H-MRS no statistically significant difference in choline (Cho)/creatine (Cr) and N-acetylaspartate (NAA)/Cr was associated with LEP. A lower Cho/Cr (p = 0.006) and NAA/Cr (p = 0.078) was observed in brains with hemosiderin. Linear-regression analysis showed no statistically significant relationship between NAA/Cr or Cho/Cr with age at diagnosis, but there was a statistically significant decreasing trend of NAA/Cr and Cho/Cr with the interval since diagnosis.

CONCLUSION

Long-term brain injury in ALL survivors after CNS prophylaxis with ITMTX and CRT was reflected by decreasing NAA/Cr and Cho/Cr with the interval since diagnosis. The lower Cho/Cr associated with hemosiderin but not LEP suggested a different pathophysiology for these brain lesions.

Inferior vena cava filters--percutaneous insertion?

The incidence of deep venous thrombosis (DVT) and pulmonary embolism (PE) among Chinese is much lower than in Caucasians. The total number of inferior vena cava (IVC) filters inserted in regional hospitals in Canada (about 700 beds in Toronto General Hospital) and Hong Kong (about 1,250 beds in Pamela Youde Nethersole Eastern Hospital) also reflects this. Thirty-six IVC filters were deployed in Toronto General Hospital, compared to 8 IVC filters inserted in Pamela Youde Nethersole Eastern Hospital from August 1997 to September 1998. Despite this, the physician may encounter patients with thromboembolic disease who require inferior vena cava interruption. The usual indication will be pulmonary embolism with contraindications to, or failure or complications of, anticoagulation therapy. It is important for angiographers to be familiar with the technique of percutaneous insertion of IVC filters. The types of IVC filters, techniques of insertion and guidelines relating to the choice of a filter would be discussed.

A cervical ectopic pregnancy managed by medical treatment and angiographic embolization

Medical treatment in the form of systemic methotrexate with or without local methotrexate/potassium chloride is effective for early cervical pregnancy. It should be the treatment of choice in suitable cases. Haemorrhagic complications can be effectively managed by angiographic embolization. A case report illustrating these points is presented.

Frequency of ischemia during intracoronary ultrasound in women with and without coronary artery disease

Myocardial ischemia is common during ICUS imaging in women with and without CAD. Although no long-term adverse effects occurred in our small sample, a larger sample of women is required to confirm our observations and to determine the precise mechanisms of ischemia. Such studies may determine whether the smaller diameter of coronary vessels in women makes the women more vulnerable than men to the occurrence of chest pain and ischemia during ICUS. Although ICUS is valuable in guiding coronary interventions, disposable catheters are costly. Studies are required to assess the cost-benefit ratio of incorporating ICUS with coronary interventional procedures. Until more is known, we recommend that nurses educate patients about ICUS, monitor them closely for ischemia and arrhythmias during the procedure, and consider obtaining 12-lead ECGs when patients undergo and ICUS procedure.

Frequency of ischemia during intracoronary ultrasound in women with and without coronary artery disease

Myocardial ischemia is common during ICUS imaging in women with and without CAD. Although no long-term adverse effects occurred in our small sample, a larger sample of women is required to confirm our observations and to determine the precise mechanisms of ischemia. Such studies may determine whether the smaller diameter of coronary vessels in women makes the women more vulnerable than men to the occurrence of chest pain and ischemia during ICUS. Although ICUS is valuable in guiding coronary interventions, disposable catheters are costly. Studies are required to assess the cost-benefit ratio of incorporating ICUS with coronary interventional procedures. Until more is known, we recommend that nurses educate patients about ICUS, monitor them closely for ischemia and arrhythmias during the procedure, and consider obtaining 12-lead ECGs when patients undergo and ICUS procedure.

MRI demonstration of subarachnoid neurocysticercosis simulating metastatic disease

We present a patient with neurocysticercosis with spinal subarachnoid spread who presented with lower back pain and progressive numbness and weakness of the left leg. MRI of the spine simulated metastasis. MRI of the brain demonstrated a "bunch of grapes" appearance in the basal cisterns, characteristic of cysticercosis.

Magnetic resonance imaging evaluation of the pituitary gland and hypothalamus in thalassaemic children with elevated serum ferritin levels

OBJECTIVE

Despite modern treatment with hypertransfusion and chelation therapy, growth retardation continues to be observed in a significant proportion of thalassaemic children. The underlying reason remains unclear, but hypothalamic-pituitary axis disorder has been implicated. We aimed to assess iron overloading in the hypothalamus and pituitary gland in thalassaemic children with elevated serum ferritin, with and without growth retardation.

METHODOLOGY

Twelve thalassaemic children on hypertransfusion and chelation therapy with high serum ferritin were investigated with magnetic resonance imaging (MRI). Five children, all over 10 years of age, had growth retardation. Gradient recalled echo sequence was used to highlight any susceptibility effect that could be due to iron in the hypothalamus or pituitary gland.

RESULT

There was no evidence of abnormal hypointense signal in the hypothalamus or pituitary gland in the patients studied, regardless of the presence of growth retardation.

CONCLUSION

There was no apparent characteristic MRI appearances of iron deposition in the hypothalamus or pituitary gland in thalassaemic children with high serum ferritin.

Carcinoma showing thymiclike differentiation (CASTLE tumor)

A 67-year-old woman had had a neck mass for 10 years, which recently increased in size. Sonographic, CT, and MR examinations showed a mass in the carotid and posterior spaces (triangle) extending from below the submandibular gland to the supraclavicular fossa, displacing the common carotid artery and the sternomastoid anteriorly. The mass was solid, noncalcified with lobulated outlines, hypoechoic on sonograms, of soft-tissue density on CT scans, isointense on T1-weighted MR images, hyperintense on T2-weighted MR images, and enhanced mildly after injection of contrast material on CT and MR studies. Histologic examination revealed a carcinoma showing thymiclike differentiation, a rare tumor of the neck and thyroid gland.

Penetration of dimyristoylphosphatidylcholine monolayers and bilayers by model beta-blocker agents of varying lipophilicity

Penetration of model beta-blockers, propranolol, oxprenolol, metaprolol, and nadolol, into dimyristoylphosphatidylcholine (DMPC) monolayers cast on a pH 7.4 phosphate buffer (mu = 0.155 adjusted with NaCl) at 25 degreesC was monitored using a film balance equipped with a Wilhelmy plate for measuring changes in surface pressure. Drug solution (pH 7.4) is injected below the surface of the monolayer. The difference in surface pressure, Delta pi, for each drug concentration added to the monolayer was measured at equilibrium. Delta pi increased with increasing drug concentration. Consistent with the relative lipophilicities, the Delta pi vs drug concentration slopes were as follows: propranolol > metaprolol > oxprenolol > nadolol. The intrinsic surface activity of the beta-blockers was also determined in the absence of the lipid. Differential scanning calorimetry (DSC) measurements were also made on DMPC bilayers in the above buffer. DMPC suspended in buffered drug solutions were scanned over a temperature range of 5 degrees to 40 degreesC at a scan rate of 0.091 degreesC/min. The DSC studies indicate that the DMPC thermotropic phase behavior is modulated by these compounds as follows: propranolol >> metaprolol congruent with oxprenolol > nadolol which agrees with reported partition coefficients as well as the above Delta pi observations. However, an accounting of the intrinsic surface activity of these compounds results in a lower than expected affinity for the DMPC monolayer.

The role of ultrasound and oesophagography in the management of acute suppurative thyroiditis in children associated with congenital pyriform fossa sinus

The thyroid is remarkably resistant to infection. Hence, when an infection does occur, the presence of a pyriform fossa sinus must be considered, particularly if it is recurrent and left sided. The aim of this paper is to alert radiologists to the existence, clinical presentation, and ultrasonographic and oesophagographic appearances of a pyriform fossa sinus. We present the role of ultrasound and oesophagography in five children with pyriform fossa sinus associated with suppurative thyroiditis. In four children the abnormality was on the left and on the right in one.

Frequency, duration, magnitude, and consequences of myocardial ischemia during intracoronary ultrasonography

To determine the frequency, duration, magnitude, and possible adverse effects of ischemia during intracoronary ultrasonography, real-time standard 12-lead electrocardiograms were recorded before, during, and after ultrasonography. Ischemia was defined as new-onset ST segment deviation of > or = 1 mm in one or more leads, measured at J + 80 msec. The magnitude of ischemia was expressed as the sum of absolute ST segment deviations across 12 leads. Eighteen (67%) of 27 patients had ischemia during intracoronary ultrasonography. The electrocardiogram resembled the characteristic pattern observed with occlusion of the vessel under study, involving ST segment elevation in contiguous leads in 89% of patients. A higher proportion of women (88%) had ischemia than men (58%), and women had smaller arterial lumenal areas compared with men (6.3 vs 9.1 mm2; p < 0.05). Individuals with ischemia were smaller than those without ischemia (body surface area = 1.99 vs 1.79 m2; p = 0.01). The mean duration of ischemia was 4 minutes and the mean 12-lead ST segment deviation score was 8.5 mm (maximum 20.5 mm). No patient with ischemia during ultrasonography had complications. Ischemia is common during intracoronary ultrasonography, particularly in women and individuals with smaller vessels; however, no adverse outcomes occur as a result.

One-stage thoracoscopic oesophagectomy: ligature intrathoracic stapled anastomosis

Thoracoscopic oesophagectomy is usually performed in stages and intrathoracic oesophagogastric anastomosis often requires mini-thoracotomy or extension of the thoracoscopic incisions. This paper describes a new technique whereby such an operation could be completed in one stage and the need to extend the thoracoscopic incisions is obviated.

Synchronous embolization of the gastroduodenal artery and the inferior pancreaticoduodenal artery in patients with massive duodenal hemorrhage

PURPOSE

To assess the efficacy and safety of synchronous embolization of the gastroduodenal artery (GDA) and inferior pancreaticoduodenal artery (IPDA) in patients with massive duodenal hemorrhage.

PATIENTS AND METHODS

All cases of synchronous embolization of the GDA and IPDA at the authors' hospital between 1980 and 1989 were retrospectively reviewed.

RESULTS

Bleeding was successfully controlled acutely in all six patients who underwent synchronous embolization. Clinical evidence of recurrent hemorrhage was found in two patients, but repeat angiography showed no extravasation of contrast material. Three patients died within 30 days of embolotherapy. In one patient who also received an infusion of vasopressin, postmortem evidence of pancreatic necrosis was found.

CONCLUSION

Synchronous embolization of the GDA and IPDA can be an effective treatment for continuing duodenal hemorrhage after failed endoscopic therapy in patients considered a poor surgical risk. The procedure should be undertaken only as a lifesaving measure due to the risk of pancreatic and duodenal necrosis.

Epidural mass related to calvarial aneurysmal bone cyst: computed tomographic and magnetic resonance demonstration

The computed tomographic and magnetic resonance appearance of a calvarial aneurysmal bone cyst is described. Both forms of imaging demonstrate an epidural mass in the right occiput. The fluid-fluid levels in the mass on the T2-weighted images are characteristic of, though not specific for, aneurysmal bone cyst.

Desmoplastic infantile ganglioglioma: CT and MRI features

We present three cases of desmoplastic infantile ganglioglioma in patients admitted to our institution in the past 8 years. CT and MR findings are discussed. Typically, these lesions are located in the frontal and parietal lobes, appearing as cystic tumors with a solid cortical component within the cerebrum, which enhances intensely, and moderate surrounding edema.

DNA cleavage, antiviral and cytotoxic reactions photosensitized by simple enediyne compounds

Very potent antibiotic antitumor natural products contain a enediyne moiety which, upon thermal activation, is capable of abstracting hydrogens from DNA. 1,6-Diphenyl-3-hexene-1,5-diyne was selected as a candidate for inducing DNA strand breaks photochemically. Easily interconverted with light, both geometric isomers 1 and 2 were expected to be phototoxic. As anticipated, they photosensitized the production of strand breaks in double-stranded supercoiled pBR322, and in single-stranded M13 DNA. The DNA cleavage reactions were favored by the presence of oxygen and were inhibited by ethanol. Preliminary experiments with the (Z)-isomer indicated moderate light-dependent antiviral activity against human immunodeficiency virus (HIV), Sindbis virus, and mouse cytomegalovirus. The enediynes were cytotoxic to Escherichia coli, a gram-negative organism, to Streptococcus faecalis, a gram-positive organism, to Daphnia magna and to fish (Pimephales promelas), but only in the presence of light. The production of o-terphenyl, the expected product of Bergman cyclization of 1, could not be confirmed. However, both 1 and 2 photosensitized the formation of singlet oxygen and of superoxide anion radical, and photodynamic reactions could have been responsible for some of the phototoxic reactions observed.

Phototoxicity of (1H-indenyl)thiophenes

The (1H-indenyl)thiophene derivatives 2 and 3 were recently reported to be excellent singlet oxygen sensitizers, comparable to alpha-terthienyl (1). The phototoxicity of these compounds was compared, using human erythrocytes, Aedes aegypti mosquito larvae, Daphnia magna, and fish (fathead minnows, Pimephales promelas). The known ranking of the photooxidation properties was found to be a good predictor of phototoxic properties in erythrocytes and mosquito larvae but not in daphnias. All three compounds photosensitized the cleavage of supercoiled pBR322 DNA to the same extent.

Pneumomediastinum caused by subcutaneous emphysema in the shoulder. A rare complication of arthroscopy

Severe subcutaneous emphysema following arthroscopy of the shoulder developed in a 62-year-old man. It subsequently evolved into pneumomediastinum with respiratory distress, but the patient recovered spontaneously. To our knowledge, this constitutes the first report of pneumomediastinum caused by subcutaneous emphysema in the shoulder.

Endobronchial actinomycosis mimicking pulmonary neoplasm

A 60 year old man had recurrent pneumonia. Bronchoscopy disclosed a necrotic mass in the left lower lobe bronchus, which histological examination showed to contain sulphur granules. The endobronchial mass had disappeared by the second bronchoscopy one week later. The patient was treated with penicillin for one year and was cured. Actinomycosis must be included in the differential diagnosis of an endobronchial mass.

Upper airway obstruction as the sole manifestation of rheumatoid arthritis

A 51-year-old woman with a history of rheumatoid arthritis (RA) suddenly developed laryngeal stridor. Rheumatoid factor was positive and the erythrocyte sedimentation rate was elevated, but she had no evidence of acute peripheral arthritis at this time. A flexible laryngoscopy revealed cricoarytenoid arthritis which was the sole clinical manifestation of active RA. Involvement of the cricoarytenoid joints must be considered in patients with RA with laryngeal stridor even in the absence of active peripheral arthritis.

Systemic air embolism: a complication of ventilator therapy in hyaline membrane disease

Systemic air embolism in infants with hyaline membrane disease on positive pressure ventilation is a serious and frequently fatal complication. It is essential for both the paediatrician and radiologist to be aware of this disease entity. The incidence is increasing because of improved survival of very low birth weight infants and more aggressive therapy. We report two examples of systemic air embolism in infants.