Dipyridamole-induced STEMI: case report and review of the literature

Dipyridamole nuclear myocardial perfusion imaging is a safe and useful modality for assessing myocardial ischemia. It is the modality of choice for cardiac risk stratification in patients who are unable to exercise. Intravenous dipyridamole causes coronary vasodilation and may result in heterogeneity of coronary blood flow in significant coronary artery disease. Ischemic electrocardiographic changes following pharmacological stress testing are less likely to occur compared with exercise stress tests. Ischemia is more likely to be present in the form of ST depression, with ST-segment elevation being exceedingly rare. We present the case of a 73-year-old patient who developed ST-segment elevation myocardial infarction following pharmacologic stress testing.

Management of vagus nerve simulation therapy in the peri-operative period: Guidelines from the Association of Anaesthetists: Guidelines from the Association of Anaesthetists

Vagus nerve stimulation is a well-established treatment option for patients with drug-resistant epilepsy and has an expanding range of other clinical indications. Side effects of vagus nerve stimulation therapy include: cough; voice changes; vocal cord adduction; rarely, obstructive sleep apnoea; and arrhythmia. Patients with implanted vagus nerve stimulation devices may present for unrelated surgery and critical care to clinicians who are unfamiliar with their function and safe management. These guidelines have been formulated by multidisciplinary consensus based on case reports, case series and expert opinion to support clinicians in the management of patients with these devices. The aim is to provide specific guidance on the management of vagus nerve stimulation devices in the following scenarios: the peri-operative period; peripartum period; during critical illness; and in the MRI suite. Patients should be aware of the importance of carrying their personal vagus nerve stimulation device magnet with them at all times to facilitate urgent device deactivation if necessary. We advise that it is generally safer to formally deactivate vagus nerve stimulation devices before general and spinal anaesthesia. During periods of critical illness associated with haemodynamic instability, we also advise cessation of vagus nerve stimulation and early consultation with neurology services.

Impact of COVID-19 on autism spectrum disorder management - a therapist perspective

Introduction

Therapist led interventions form a core element in the management of children with Autism Spectrum Disorder (ASD) in India. COVID-19 pandemic has disrupted several aspects of ASD management.

Objectives

This study aims to understand the impact of COVID-19 pandemic on ASD therapies from a therapist perspective.

Methods

An online survey was conducted using a google form questionnaire disseminated among ASD therapists. The form was open for response between 23^rd of June and 23^rd of July 2020. The responses were extracted into an excel sheet and analysed using descriptive statistics.

Results

41 out of 75 therapists with mean age of 44 years (21 – 58 years) responded to the survey. 48% were women. Majority of them were either special educators (49%) or ASD therapists (32%) with professional experience of >5 years (63%). Majority of the therapists felt that there is significant disruption during the pandemic with reduction in conventional therapies (63% to 17%) and increase in online therapies (15% to 61%). They also felt that this disruption had moderate to severe impact on child’s learning (73%) and parents emotional and psychological well being (85%). Only 22% of therapists were using digital based therapy (DBT) before the pandemic. Although 51% of the therapists were not entirely sure whether DBT augments parents and therapists’ efforts, majority (65%) were willing to use them.

Conclusions

COVID-19 pandemic has significantly disrupted ASD therapy in India. Willingness to use online and digital based therapies could open up a new dimension. Reliable and effective Artificial-Intelligence based therapies are the need of the day.

Disclosure

Medical advisor for CognitiveBotics

Abstract P5-10-01: Using whole genome sequencing and somatic mutation signatures to unravel insight into familial breast cancer aetiology

Approximately 10-15% of breast cancers are associated with a strong family history of disease. Pathogenic variants in BRCA1, BRCA2 or other moderate to highly penetrant susceptibility genes (e.g. TP53, ATM, CHEK2, PALB2 and PTEN) account for a number of breast cancer families. However, for over 50% of families the underlying genetic contribution to their risk remains unknown (termed here as non-BRCA1/2). This has a profound impact for how individuals and their families are managed in the clinic. We applied whole genome sequencing (WGS) to determine whether somatic mutation analysis can reveal insight into the aetiology of familial breast cancer. The full repertoire of somatic mutations was evaluated in 26 BRCA1, 22 BRCA2 and 32 non-BRCA1/2 tumours; including SNPs, indels, copy number changes and structural rearrangements, and mutational signatures. Genomes were also analysed using the HRD Index and HRDetect, as predictors of homologous recombination deficiency. BRCA1, BRCA2 and non-BRCA1/2 tumours exhibited a different burden of mutations, a different spectrum of mutational signatures and different telomere length. Based on collective patterns of mutation signatures, tumours were classified as 'BRCA1-like', 'BRCA2-like' or 'non-BRCA1/2-like' with a 15% rate of tumour re-classification from their original clinical BRCA status. The results demonstrate the power of WGS to differentiate between BRCA1 and BRCA2 driven tumours; in the identification of double-pathogenic germline mutation carriers based on the resulting somatic mutation signature; and in the interpretation of BRCA unclassified variants. WGS of tumour genomes reveals fascinating insights into tumour aetiology and could compliment current genetic testing of breast cancer families.

Citation Format: Simpson P, Nones K, Johnson J, Newell F, Patch A-M, Thorne H, Kazakoff S, De Luca X, Parsons M, Ferguson K, Reid L, McCart Reed A, Srihari S, Lakis V, Davidson A, Mukhopadhyay P, Holmes O, Xu Q, Wood S, Leonard C, Beasley J, Degasperi A, Nik-Zainal S, Ragan M, Spurdle A, Khanna KK, Lakhani S, Pearson J, Chenevix-Trench G, Waddell N. Using whole genome sequencing and somatic mutation signatures to unravel insight into familial breast cancer aetiology [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-10-01.

Painful Bladder Syndrome/Interstitial Cystitis Successful Treatment with Montelukast: A Case Report and Literature Review

Painful bladder syndrome/interstitial cystitis (PBS/IC) is a chronic condition characterized by pelvic pain, urinary frequency, and urgency for more than six months in the absence of urinary tract infections. The etiology of PBS/IC is still an enigma. PBS/IC is challenging for doctors to diagnose because its symptoms overlap with other diseases such as urinary tract infection, overactive bladder, or endometriosis. Hence, it is diagnosed after excluding those diseases. The prognosis of PBS/IC may vary because of multiple treatment options. In this study, we are documenting a 26-year-old female patient who was successfully treated with montelukast after diagnosed with PBS/IC.

Subacute Infective Endocarditis of Aortic Valve During Pregnancy

Bacterial infective endocarditis is a rare but a life-threatening infection during pregnancy. Infective endocarditis during pregnancy is often associated with a congenital heart condition or an earlier history of rheumatic heart disease. In pregnant women with infective endocarditis, the maternal and fetal mortality rate can reach as high as 33% and 29%, respectively. In most cases, infective endocarditis runs a subacute course and involves the mitral valve, nonetheless, rarely it can involve the aortic valve as well. We are documenting a rare case of subacute infective endocarditis in a 26-year-old pregnant female with severe aortic stenosis with associated multiple systemic emboli. The patient was managed by urgent cesarean section at 35 weeks of gestation followed by aortic valve replacement; there was no maternal or fetal mortality. This case report highlights the importance of early diagnosis, and timely management of infective endocarditis in pregnant women to prevent maternal and fetal death.

Energy Drinks and Myocardial Infarction

The popularity and use of energy drinks have accelerated over the past decade and are a health concern worldwide. The key ingredients of energy drinks include caffeine, guarana, taurine, ginseng, and sugar. Most of the well-known side effects due to consumption of energy drinks include tachycardia, headache, anxiety, and palpitations and are frequently attributed to caffeine. Recently, a few cases of life-threatening cardiovascular events in individuals who overdosed massive quantities of caffeinated energy drinks have been reported. In this case report, we are documenting a case of myocardial infarction in a 25-year-old man who presented to the emergency department with chest pain. The patient had been consuming massive quantities of caffeinated energy drinks daily for the past week. This case report and the few previously documented studies support a possible connection between caffeinated energy drinks and myocardial infarction. The purpose of this case report is to promote awareness in the general population and the medical staff about cardiac mortality due to overdosing of massive quantities of caffeinated energy drinks.

Effect of a surgical day unit on waiting lists

The effect of a surgical day unit (SDU) on the waiting lists of a busy district general hospital is reported over a 4-year period. During this time, 18 (15%) of the general surgical beds were closed for financial reasons. A real saving rather than an apparent one is reported due to the work expansion in the SDU.

Abstract P1-04-05: RNA immunoprecipitation reveals lncRNA-protein interactions in basal-like breast cancer

Interactions between long non-coding RNAs (lncRNAs) and proteins contribute to the epigenetic regulation of gene expression, and defects in such interactions have been implicated in several diseases, including cancer. Basal-like breast cancer accounts for approximately 15% of all breast cancer and is a major clinical problem given its poor survival and lack of responsiveness to targeted breast cancer treatments. DNA methylation is non-random and is much more pronounced in basal-like breast cancer (BLBC) compared to other molecular subtypes of breast cancer, raising the possibility that hypermethylation could be important in the genesis of BLBCs. LncRNAs are aberrantly expressed in multiple subtypes of breast cancer, including BLBC, and are considered to have significant prognostic potential. In order to explore the potential roles of DNA methylation and lncRNAs in BLBC, we investigated lncRNA-protein interactions using bioinformatics and molecular techniques, focusing on proteins that actively perform DNA methylation - the DNA methyltransferase (DNMT) family. Our novel bioinformatic methods revealed that BLBC may be sub-classified according to methylation profile in a way that could predict disease survival. We then identified candidate lncRNAs that are over-expressed in BLBC and statistically predicted to interact with DNMT proteins. Using RNA immunoprecipitation of BLBC cell lines, we have identified potential lncRNA-protein interactions that may be involved in epigenetic remodelling in BLBC. The role of these lncRNAs in epigenetic gene regulation and BLBC is currently being explored.

Citation Format: Northwood K, Saunus J, Milevskiy M, Lakhani S, Brown M. RNA immunoprecipitation reveals lncRNA-protein interactions in basal-like breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-04-05.

Abstract P1-05-16: An integrated molecular analysis of invasive lobular carcinoma

Background: Invasive lobular carcinoma (ILC) is the most commonly diagnosed special histological type of breast cancer, accounting for up to 15% of all cases. Accumulating data suggests the biology and clinical features of ILC differ to those of the more commonly diagnosed Invasive Carcinoma of No Special Type (IC-NST), including evidence of there being an overall worse long term outcome associated with ILC. Several large-scale molecular profiling studies have recently been published regarding ILC, highlighting molecular heterogeneity and important drivers of tumour behaviour. We hypothesize that an integrative analysis of gene expression and DNA copy number data will identify novel drivers, and prognostic and predictive biomarkers of lobular phenotype.

Methods: Gene expression and copy number data from ILC tumours profiled in-house (n=25), METABRIC (n=125) and TCGA (n=145) were assembled and analysed. Integration of genome and transcriptome data was performed using two methods. Firstly, by Spearman correlation with a meta-analysis by combining gene level correlation coefficients from each study using a random effects model, weighting each study with inverse variance. Secondly using ANOVA, followed by combining gene level p-values across studies using Stouffers Z-score. Disease specific survival was examined at an individual gene level and using all genes simultaneously (via a Cox Boost analysis) to identify gene expression changes that are associated with poor outcome.

Results: DNA copy number profiling identified recurrent gains (1q, 8q, 16p), losses (11q, 16q) and amplifications (1q32, 8p12-p11.2, 11q13). 11q13 amplifications were prevalent at a higher frequency in patients with poor outcome compared to patients with better outcome. The integrative analysis identified 1928 candidate genes whose expression was associated with gene copy number; as expected being enriched from genome regions highlighted above. One hundred and sixty of these genes were of prognostic significance in the METABRIC ILC cohort, several are known cancer drivers (e.g. PBX1, CCND1) and five new candidates are being investigated as novel prognostic biomarkers by immunohistochemistry.

Conclusions: An integrated molecular analysis of ILC has identified a large number of gene expression changes that are dictated by gene copy number in ILC. Some of these are expected to influence tumour behavior and to highlight aggressive cancers with poor prognosis.

Citation Format: Lal S, McCart Reed A, Nones K, Wockner L, Song S, Lakhani S, Simpson P. An integrated molecular analysis of invasive lobular carcinoma [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-05-16.

Distinctive Expression of Cancer/Testis-X Antigens in a Subset of ER Negative Breast Carcinomas

Background: Cancer/testis-X antigens are a multigene family that are predominantly expressed in human germ line cells, with little or no expression in somatic adult tissues, but become aberrantly activated in various malignancies. Some such CT-X antigens represent ideal targets for cancer immunotherapy and have already been used in clinical testing. In contrast to melanomas, bladder, lung, ovarian and hepatocellular carcinomas which show higher levels of CT-X antigen expression, the reports in breast cancers have been inconclusive to date and a comprehensive gene expression and clinicopathological analysis has yet to be performed.Material and Methods: Using sequencing data as well as nine publicly available gene expression data sets, we analyzed the expression of Cancer/testis-X antigens in more than 1900 primary breast cancers. Complementary analysis was performed on three tissue microarrays comprising a total of 201 primary breast carcinomas and 53 brain metastases. Clinical information on the ER-, PR-, HER2, Ki67, p53, EGFR and basal markers was available for statistical analysis.Results: A significantly higher expression of Cancer/testis-X antigens was found in ER negative breast carcinomas over different data sets with a concordant gene expression pattern of several Cancer/testis-X antigens. Members of the MAGEA family and NY-ESO-1/CTAG1B were consistently the most prevalent. Immunohistochemical analyses confirmed a significant correlation of MAGEA family and NY-ESO-1/CTAG1B with ER negative (pValue < 0.0001), PR negative (pValue < 0.01) and Ki67 staining (pValue < 0.0001). Many of these tumors were also positive for basal markers.Discussion: Previous studies of Cancer/testis-X antigens in breast have focused on ER positive cancers, in smaller subsets and provided inconclusive results. Using comprehensive gene expression data sets and tissue microarrays, we have demonstrated a significant association of MAGEA family and NY-ESO-1/CTAG1B with ER/PR negative breast cancer. Since these cancers represent a subgroup for which less therapeutic modalities are available, we propose the use of MAGEA and NY-ESO-1/CTAG1B cancer vaccines in the adjuvant setting as an approach to restricting tumor growth and metastases. Clinical trails using MAGEA and NY-ESO-1/CTAG1B are warranted.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3139.

Anaesthesia for endovascular management of cerebral aneurysms

Subarachnoid haemorrhage due to rupture of cerebral aneurysms is a multisystem disease. Treatment of the condition in the past has relied on craniotomy and clipping of the aneurysm to prevent a recurrent haemorrhage. There is now emerging evidence to suggest that endovascular treatment of cerebral aneurysms may reduce the morbidity associated with open surgery. The anaesthetic management of interventional neuroradiology also creates new challenges due to the novel approach to treatment. Anaesthetists need to be familiar with this procedure and the management of potential complications. This review provides an overview such considerations.

Continued axillary sampling is unnecessary and provides no further information to sentinel node biopsy in staging breast cancer

INTRODUCTION

Sentinel lymph node biopsy (SLNB) has become increasingly accepted as a diagnostic method to stage the axilla in breast cancer, selecting women with a positive sentinel node for completion axillary clearance. As SLNB became established, many surgeons supplemented SLNB to sample a minimum of four lymph nodes, on the assumption that the four-node technique is supported by randomised trial data. We hypothesised that the practice of undirected sampling to supplement SLNB adds little information to the status of the residual axilla.

METHODS

One hundred and sixty-five patients with early breast cancer were studied. Following successful identification of the sentinel node, 84 women had completion axillary dissection and 81 women had an axillary sample with at least four nodes available for pathological assessment.

RESULTS

Following successful identification of the sentinel node in 165 patients, the false negative rate (FNR) was 2/44=4.5% (95% CI 0.6-15.5), sensitivity 42/44=95.5% (84.5-99.4) and negative predictive value (NPV) 121/123=98.4% (94.2-99.8). In the axillary dissection cohort, the FNR was 2/26=7.7% (0.9-25.1), sensitivity 24/26=92.3% (74.9-99.1) and NPV 58/60=96.7% (88.5-100). In the axillary sample group, the FNR was 0/18=0% (0-18.5), sensitivity 18/18=100% (81.5-100) and NPV 63/63=100% (94.3-100). The SLNB was the only positive node in 12/26 (46.2%) in the axillary dissection group and 10/18 (55.6%) in the axillary sampling group. There was no patient in the axillary sampling group where the sample node was positive and the sentinel node negative.

CONCLUSION

Once SLNB is validated within the multidisciplinary unit, undirected sampling of the axilla following identification of the sentinel node(s) is unnecessary. The additional sampling of non-sentinel nodes has no role to play either in the assessment of a potential false negative SLNB nor as predictive information on the status of the residual axillary nodes.

The UK national study of magnetic resonance imaging as a method of screening for breast cancer (MARIBS)

The UK national study of magnetic resonance imaging as a method of screening for breast cancer (MARIBS) is in progress. The study design, accrual to date, and related research projects are described. Revised accrual rates and expected recruitment are given. 15 cancers have been detected to date, from a total of 1236 screening measurements. This event rate and the tumour grades reported are compared with recent reports from other studies in women at high risk of breast cancer.

A comparison of microbiologic flora of the sinuses and airway among cystic fibrosis patients with maxillary antrostomies

The placement of maxillary antrostomies among cystic fibrosis (CF) patients has been used as a treatment to allow localized antibiotic lavage of infected sinus passages. This procedure is increasingly recommended by lung transplantation centers as a prerequisite prior to accepting a CF patient as a candidate for transplantation. Our study attempts to define the degree of identity between sinus, endotracheal and sputum cultures from 35 patients. The samples (n = 137) were collected within two weeks of each other. An analysis of the microbiologic type, strain, and antibiotic resistance patterns was undertaken. Randomization analysis was performed and a p-value of < 0.05 was considered significant. The results indicated a high degree of correlation between sinus-sputum pairs (n = 55) and endotracheal samples (p < 0.008). This study provides evidence that there is a potential for cross-infection between sinus passages and the lower airway. The localized irrigation of CF sinus cavities post-transplantation may be warranted in an attempt to reduce bacterial counts and potential direct infection of the allograft. However, it is unlikely that this will eliminate this risk because bacterial colonization continues and the CF trachea is another source of infection.

Diagnosis of breast cancer using elastic-scattering spectroscopy: preliminary clinical results

We report on the first stages of a clinical study designed to test elastic-scattering spectroscopy, mediated by fiberoptic probes, for three specific clinical applications in breast-tissue diagnosis: (1) a transdermal-needle (interstitial) measurement for instant diagnosis with minimal invasiveness similar to fine-needle aspiration but with sensitivity to a larger tissue volume, (2) a hand-held diagnostic probe for use in assessing tumor/resection margins during open surgery, and (3) use of the same probe for real-time assessment of the "sentinel" node during surgery to determine the presence or absence of tumor (metastatic). Preliminary results from in vivo measurements on 31 women are encouraging. Optical spectra were measured on 72 histology sites in breast tissue, and 54 histology sites in sentinel nodes. Two different artificial intelligence methods of spectral classification were studied. Artificial neural networks yielded sensitivities of 69% and 58%, and specificities of 85% and 93%, for breast tissue and sentinel nodes, respectively. Hierarchical cluster analysis yielded sensitivities of 67% and 91%, and specificities of 79% and 77%, for breast tissue and sentinel nodes, respectively. These values are expected to improve as the data sets continue to grow and more sophisticated data preprocessing is employed. The study will enroll up to 400 patients over the next two years.

Improving the reproducibility of the MCF-7 cell proliferation assay for the detection of xenoestrogens

The MCF-7 cell proliferation assay is potentially a simple and highly reproducible tool for the identification of estrogenic compounds. However, its widespread use has been complicated by the lack of a standardised protocol, resulting in considerable inter-laboratory variability. We have explored the sources of variability both in relation to cell lines and test regimens and report on optimised procedures for the identification of estrogenic agents. Two supposedly identical MCF-7 parent cell lines (designated UCL and SOP), and the BUS subline were cultured according to an existing protocol, and responses to 17-estradiol (E2) assessed. Despite yielding almost identical EC50 values, the proliferative response varied widely between cell lines from 0.98-fold over controls (UCL) to 8.9-fold (BUS) indicating major differences between them. The underlying causes may be genetic, and to assess this we used comparative genomic hybridisation (CGH), a technique which allows the detection of DNA sequence copy number changes on a genome-wide scale. Although numerous similarities existed between the different cell lines, the least oestrogen-responsive line (MCF-7/UCL) exhibited the greatest number of cytogenetic changes, many of which were not seen in MCF-7/SOP cells. We suggest that care must be taken, therefore, when choosing a cell line for MCF-7 cell-based experiments. Selecting the MCF-7/SOP line for further work, we carried out a thorough and systematic optimisation of the MCF-7 cell proliferation assay, finding that a 72-h period in oestrogen-free medium before treatment strongly influenced the cells response to E2. With 1 nM E2, proliferation increased from 1.5-fold to 6.5-fold relative to vehicle-treated controls, a response similar to that seen with MCF-7/BUS cells in the E-SCREEN protocol devised by Soto et al. With parent MCF-7 cells, other laboratories have reported only 4.5-fold increases as maximal. Here we present evidence that the choice of cell line and culture conditions are crucial in determining test outcomes, and once chosen and adhered to the assay yields reproducible results.

Acquisition of neuroendocrine characteristics by prostate tumor cells is reversible: implications for prostate cancer progression

Neuroendocrine (NE) cells occur as scattered foci within prostatic adenocarcinoma, similar to their distribution within ductal epithelial cells of the normal prostate. However, the density of NE cells is often greater in prostate carcinomas than in normal tissue, and the frequency of NE cells correlates with tumor grade, loss of androgen sensitivity, autocrine/paracrine activity, and poor prognosis. Although NE cells are nonmitotic, proliferating cells are found in direct proximity to them, suggesting that NE cells provide paracrine stimuli for surrounding carcinoma cells. In vitro, differentiation of the LNCaP and PC3M prostatic tumor cell lines to a NE phenotype can be induced by dibutyryl cyclic AMP (cAMP), suggesting that physiological agents that increase intracellular concentrations of cAMP might regulate NE differentiation in vivo. Indeed, we demonstrate in this report that LNCaP cells acquire NE characteristics in response to treatment with physiological and pharmacological agents that elevate intracellular cAMP, agents such as epinephrine, isoproterenol, forskolin, and dibutyryl cAMP. The androgen-independent LNCaP-derived cell line C4-2 also responded to these agents, indicating that cells representing later stages of tumor progression are also capable of differentiation. The NE phenotype in this study was monitored by the appearance of dense core granules in the cytoplasm, the extension of neuron-like processes, loss of mitogenic activity, and expression of the NE markers neuron-specific enolase, parathyroid hormone-related peptide, neurotensin, serotonin, and chromogranin A. However, contrary to previous reports, we observed rapid loss of the NE phenotype in both LNCaP and C4-2 cells upon withdrawal of inducing agents. Withdrawal also resulted in a rapid, dramatic increase in tyrosine kinase and mitogen-activated protein kinase activities, suggesting that activation of these intracellular signaling enzymes may be important for reentry into the cell cycle. Together, these results indicate that chronic cAMP-mediated signaling is required to block proliferation of prostate tumor cells and to induce NE differentiation.

Nascent transcript-binding protein of the pea chloroplast transcriptionally active chromosome

This study describes the nascent RNA-binding protein of the pea chloroplast transcriptional complex. The protein has been identified by photoaffinity labelling of the transcriptionally active chromosome (TAC) which utilizes the endogenous plastid DNA as template. UV irradiation of lysed chloroplast or the isolated TAC under conditions optimized for transcription photocross-links nascent radiolabelled transcripts (up to 250 nucleotides in length) to a 48 kDa protein. The photoaffinity labelling of the transcript-binding protein is dependent on UV irradiation, is maximal after about 30 min of irradiation, and is completely dependent on transcriptional activity; no cross-linkage has been observed with pre-synthesized RNA. Cross-linkage is influenced by salts and inhibitors in accordance with their effects on transcription. The photoconjugate is composed of protein and RNA moieties, and can be hydrolysed by several proteases. However, the cross-linked transcript is protected from nucleases until the protein is removed. Manganese enhances photoaffinity labelling of the transcript-binding protein, and this is paralleled by an increase in total transcriptional activity of TAC. This protein was isolated by 2-dimensional polyacrylamide gel electrophoresis and the sequence of 15 amino acid residues at the amino terminus was determined. The nascent transcript-binding protein appears to be involved in the transcription of all three classes of chloroplast genes. We also found a polypeptide of identical molecular weight to get cross-linked to nascent transcripts in chloroplasts isolated from other legumes such as Cicer arietenum, Vigna radiata and Phaseolus vulgaris, and monocots like Zea mays, Oryza sativa and Pennisetum americanum.

Dual phosphorylation and autophosphorylation in mitogen-activated protein (MAP) kinase activation

p42mapk [mitogen activated protein (MAP) kinase; extracellular signal-regulated protein kinase (ERK)] is a serine/threonine-specific protein kinase that is activated by dual tyrosine and threonine phosphorylation in response to diverse agonists. Both the tyrosine and threonine phosphorylations are necessary for full enzymic activity. A MAP kinase activator recently purified and cloned has been shown to be a protein kinase (MAP kinase kinase) that is able to induce the dual phosphorylation of MAP kinase on both the regulatory tyrosine and threonine sites in vitro. In the present paper we have utilized MAP kinase mutants altered in the sites of regulatory phosphorylation to show, both in vivo and in vitro, that phosphorylation of the tyrosine and the threonine can occur independently of one another, with no required order of phosphorylation. We also utilized kinase-defective variants of MAP kinase with mutations in either the ATP-binding loop or the catalytic loop, and obtained data suggesting that the activity or structure of the catalytic loop of MAP kinase plays an important role in its own dual phosphorylation.

Two distinct transcriptional activities of pea (Pisum sativum) chloroplasts share immunochemically related functional polypeptides

An RNA polymerase activity has been purified from pea (Pisum sativum) chloroplast extracts with a distinct transcriptional specificity for a chloroplast messenger gene. This activity (ms-RNA pol) differs from the pea RNA polymerase preparation reported by Sun, Shapiro, Wu & Tewari [(1986) Plant Mol. Biol. 6, 429-439], which specifically transcribes only the rRNA gene (rb-RNA pol). The specificity of transcription has been assessed by the synthesis in vitro of discrete transcripts of predicted sizes using cloned promoter regions of the chloroplast psbA and 16 S rRNA genes. The ms-RNA pol preparation, with polypeptides ranging in apparent molecular mass from 22 to 180 kDa, correctly initiates transcription from recombinant plasmids containing the psbA promoter and does not support 16 S rRNA promoter-directed transcription. The two activities differ also in their response to Mn2+ ions. To investigate whether the two transcriptional activities share common functional polypeptides, monoclonal antibodies were developed against the rb-RNA pol preparation. Three clones were selected on the basis of their ability to inhibit transcription in vitro of the 16 S rRNA gene by rb-RNA pol. The antibodies from these clones independently recognized three polypeptides with molecular masses of 27, 90 and 95 kDa on immunoblots. Antibodies cross-reacting with the 90 kDa polypeptide completely eliminated the specific retardation of an end-labelled 16 S rRNA promoter fragment in a mobility-shift assay, whereas the antibodies against the 95 kDa polypeptide resulted in the formation of a ternary complex (enzyme-DNA-antibody). The antibodies cross-reacting with the 27 kDa polypeptide, however, did not alter the mobility of the retarded DNA-enzyme complex on the gel. These antibodies also inhibited transcription in vitro of the psbA gene by ms-RNA pol and recognized polypeptides of identical molecular masses in the ms-RNA pol. These results show that the three polypeptides are functional components of the chloroplast transcriptional complex and appear to be involved in the transcription of both rRNA and mRNA genes. Transcriptional specificity is probably conferred by ancillary transcription factor(s) which remain to be identified.

Parathyroid hormone related protein in hypercalcaemia of Hodgkin's disease

The role of parathyroid hormone related protein (PTHRP) as a humoral mediator of hypercalcaemia was investigated in a patient with lymphocyte depleted Hodgkin's disease during an episode of hypercalcaemia, using an immunohistochemical staining technique for PTHRP on the tumour tissue and an immunoradiometric (IRMA) assay for PTHRP1-86 on the patient's plasma. The plasma PTHRP was less than 0.23 pmol/l in the range found in normocalcaemic controls, and the immunohistochemical staining was not positive for protein. PTHRP did not have a role in the pathogenesis of hypercalcaemia in this patient.

Identification of the template binding polypeptide in the pea chloroplast transcriptional complex

We have identified the template-binding polypeptide in the pea chloroplast transcriptional complex by photoaffinity labelling. This polypeptide has an apparent molecular weight of about 150 kDa and binds to both, chloroplast ribosomal (16S rRNA) and messenger (psbA) promoters. The 16S rRNA and psbA promoters were amplified from chloroplast DNA by the polymerase chain reaction and labelled with a photoactive analogue of TTP, 5-bromodeoxy UTP, as well as with alpha-32P-dCTP. Using the filter-binding assay, the conditions for binding of the RNA polymerase complex to chloroplast promoters were optimized. The polypeptide directly interacting with the template was photo-crosslinked to it and resolved by denaturing gel electrophoresis. The photoaffinity labelling of the 150 kDa polypeptide was dependent on photoactivation by UV irradiation, and the presence of chloroplast promoters. Competition experiments showed that the protein formed a strong interaction with the plastid promoters which could not be displaced by lambda-phage DNA or synthetic polynucleotides. The photo-crosslinked and nuclease-treated promoter-polypeptide complex was resistant to further digestion with DNase and RNase, but could be hydrolyzed by Proteinase K. Binding of the promoters by the 150 kDa polypeptide could not be surpressed by transcription inhibitors like rifampicin and alpha-amanitin. However, heparin (0.001%) inhibited the formation of the enzyme-promoter complex, and interfered with the photoaffinity labelling of the 150 kDa polypeptide. The extent of photoaffinity labelling of 150 kDa polypeptide exhibits some degree of correlation to total transcriptional activity under various salt concentrations. The results demonstrate that the 150 kDa polypeptide is a functional template binding polypeptide of the pea chloroplast transcription complex.

Photoaffinity labelling of the pea chloroplast transcriptional complex by nascent RNA in vitro

We have used photoaffinity labelling to examine the chloroplast RNA polymerase components which come into contact with nascent transcripts during the in vitro transcription of plastid DNA. The transcripts were synthesized in the presence of a photoactive analogue (4-thio UTP) and alpha-32P-ATP, using enriched pea chloroplast RNA polymerase preparation and a recombinant plasmid containing the plastid 16S rRNA promoter. Brief irradiation of the transcriptional complex crosslinked the photoactive nascent RNA to proximal proteins. Labelling of the transcriptional complex was dependent on 4-thio UTP and template DNA. Two polypeptides of 51 and 54 kDa were consistently crosslinked to the nascent transcripts; about 60% of the total radioactivity of the crosslinked RNA was associated with these polypeptides. In some experiments, two additional polypeptides of 38 and 75 kDa were also found to be associated with about 13% and 17% of the total crosslinked RNA radioactivity, respectively. The UV-crosslinked transcriptional complexes were stable to either DNase or S1 nuclease hydrolysis but partially sensitive to RNase T1. Insensitivity of the complex to hydrolysis with RNase H suggested that the nascent transcripts were not crosslinked to the template. The complexes could also be hydrolysed by proteinase K and thermolysin. No crosslinkage was observed when labelled RNA molecules containing 4-thio UMP residues were added after synthesis to the polymerase preparation. This suggested that the method identified only those polypeptides which came into close contact with the transcript during its synthesis. Antibodies raised against the RNA-protein complex confirmed the presence of the polypeptides in the chloroplast RNA polymerase preparation on Western blots. Preincubation of these antibodies with the chloroplast RNA polymerase inhibited plastid DNA transcription. These data showed that the transcript-binding polypeptides were functional components of the chloroplast transcriptional complex.

Early clinical pathologists. 4: John Hunter (1728-1793)

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Breast conserving surgery in the management of in situ breast carcinoma

In a retrospective review of 73 patients with in situ breast carcinoma seen in the Combined Breast Clinic at the Royal Marsden and St. George's Hospitals between 1969 and 1988, 20 (27%) were found to have in situ lobular and 53 (73%) in situ intraduct carcinoma. Of 19 patients with in situ lobular carcinoma treated by breast conserving surgery alone there were three (16%) recurrences of in situ lobular carcinoma and one (5%) of infiltrating carcinoma after a mean follow-up period of 65.8 months. Of 53 patients with in situ intraduct carcinoma, 37 were treated by breast conserving surgery alone and in this group there were 14 (38%) recurrences, of which seven (19%) were in situ intraduct and seven (19%) were infiltrating carcinoma, after a mean follow-up of 96.5 months. Following successful salvage there were no breast cancer related deaths in either group.

Enhanced anti-tumour activity of carmustine (BCNU) with tumour necrosis factor in vitro and in vivo

The effects on experimental melanoma of a combination of recombinant human tumour necrosis factor alpha (rhTNF alpha) and carmustine (BCNU) were studied in vitro and in vivo. In vitro, BCNU alone was cytotoxic to murine B16 melanoma cells, and at all concentrations of BCNU this toxicity was increased by the addition of TNF. In vivo, BCNU and TNF, when given separately, caused tumour growth delay of B16 melanoma and of human melanoma xenografts in immune-deprived mice. The combination of TNF at low dose 2.5 x 10(5) U kg-1 = 122 ng kg-1) with BCNU (35 mg kg-1) resulted in significant growth delay (compared with either drug alone) in B16 melanoma (P = 0.005). There was no significant increase in toxicity as assessed by weight loss and peripheral blood counts. Experiments with human melanoma xenografts yielded similar results (P = 0.001) but only at higher doses of TNF (1 x 10(6) U kg-1 = 489 ng kg-1). The enhancement of BCNU cytotoxicity by TNF may be important if it can be translated into patients with melanoma. A randomised study is now underway to investigate the clinical potential of this observation.

Chemotherapy for malignant melanoma: combinations and high doses produce more responses without survival benefit

In a consecutive series of studies, 164 patients with symptomatic and/or visceral metastatic malignant melanoma were treated with single agent vindesine, high dose melphalan with autologous bone marrow transplantation (AMBT), high dose BCNU with ABMT or the BOLD (bleomycin, vincristine, CCNU and DTIC) combination. The high dose treatments and the combination chemotherapy resulted in significantly higher response rates but no prolongation of survival. Factors associated with longer survival included the absence of visceral metastases, the absence of bulky disease and good performance status. For all treatments, life table estimates of survival at 1 and 2 years were only 10% and 4% respectively.

Infused vincristine and adriamycin with high dose methylprednisolone (VAMP) in advanced previously treated multiple myeloma patients

Forty-five patients with relapsed or refractory multiple myeloma received continuous infusions of vincristine (0.4 mg total dose daily for 4 days) and adriamycin (9 mg m-2 daily for 4 days) with a high dose of methylprednisolone (1 g m-2 i.v. or p.o. daily by 1 h infusion), the VAMP regimen. Sixteen (36%) responded, with a median duration of remission of 11 months and median survival of 20 months. Major toxicities encountered were infective and cardiovascular. Two smaller groups of myeloma patients were treated with high dose methylprednisolone (HDMP) alone, or VAMP plus weekly low dose cyclophosphamide (Cyclo-VAMP). HDMP produced short responses in 25% of patients with less toxicity than VAMP. Cyclo-VAMP was used in a highly selected group of patients who had previously responded to high dose melphalan. It was well tolerated and produced responses in 61% of this group.