Reduction of oligomer size modulates the competition between cluster formation and phase separation of the tumor suppressor SPOP

Phase separation compartmentalizes many cellular pathways. Given that the same interactions that drive phase separation mediate the formation of soluble complexes below the saturation concentration, the contribution of condensates versus complexes to function is sometimes unclear. Here, we characterized several new cancer-associated mutations of the tumor suppressor speckle-type POZ protein (SPOP), a substrate recognition subunit of the Cullin3-RING ubiquitin ligase. This pointed to a strategy for generating separation-of-function mutations. SPOP self-associates into linear oligomers and interacts with multivalent substrates, and this mediates the formation of condensates. These condensates bear the hallmarks of enzymatic ubiquitination activity. We characterized the effect of mutations in the dimerization domains of SPOP on its linear oligomerization, binding to its substrate DAXX, and phase separation with DAXX. We showed that the mutations reduce SPOP oligomerization and shift the size distribution of SPOP oligomers to smaller sizes. The mutations therefore reduce the binding affinity to DAXX but unexpectedly enhance the poly-ubiquitination activity of SPOP toward DAXX. Enhanced activity may be explained by enhanced phase separation of DAXX with the SPOP mutants. Our results provide a comparative assessment of the functional role of complexes versus condensates and support a model in which phase separation is an important factor in SPOP function. Our findings also suggest that tuning of linear SPOP self-association could be used by the cell to modulate activity and provide insights into the mechanisms underlying hypermorphic SPOP mutations. The characteristics of cancer-associated SPOP mutations suggest a route for designing separation-of-function mutations in other phase-separating systems.

Reduction of oligomer size modulates the competition between cluster formation and phase separation of the tumor suppressor SPOP

Phase separation is a ubiquitous process that compartmentalizes many cellular pathways. Given that the same interactions that drive phase separation mediate the formation of complexes below the saturation concentration, the contribution of condensates vs complexes to function is not always clear. Here, we characterized several new cancer-associated mutations of the tumor suppressor Speckle-type POZ protein (SPOP), a substrate recognition subunit of the Cullin3-RING ubiquitin ligase (CRL3), which pointed to a strategy for generating separation-of-function mutations. SPOP self-associates into linear oligomers and interacts with multivalent substrates, and this mediates the formation of condensates. These condensates bear the hallmarks of enzymatic ubiquitination activity. We characterized the effect of mutations in the dimerization domains of SPOP on its linear oligomerization, binding to the substrate DAXX, and phase separation with DAXX. We showed that the mutations reduce SPOP oligomerization and shift the size distribution of SPOP oligomers to smaller sizes. The mutations therefore reduce the binding affinity to DAXX, but enhance the poly-ubiquitination activity of SPOP towards DAXX. This unexpectedly enhanced activity may be explained by enhanced phase separation of DAXX with the SPOP mutants. Our results provide a comparative assessment of the functional role of clusters versus condensates and support a model in which phase separation is an important factor in SPOP function. Our findings also suggest that tuning of linear SPOP self-association could be used by the cell to modulate its activity, and provide insights into the mechanisms underlying hypermorphic SPOP mutations. The characteristics of these cancer-associated SPOP mutations suggest a route for designing separation-of-function mutations in other phase-separating systems.

Higher-order SPOP assembly reveals a basis for cancer mutant dysregulation

The speckle-type POZ protein (SPOP) functions in the Cullin3-RING ubiquitin ligase (CRL3) as a receptor for the recognition of substrates involved in cell growth, survival, and signaling. SPOP mutations have been attributed to the development of many types of cancers, including prostate and endometrial cancers. Prostate cancer mutations localize in the substrate-binding site of the substrate recognition (MATH) domain and reduce or prevent binding. However, most endometrial cancer mutations are dispersed in seemingly inconspicuous solvent-exposed regions of SPOP, offering no clear basis for their cancer-causing and peculiar gain-of-function properties. Herein, we present the first structure of SPOP in its oligomeric form, uncovering several new interfaces important for SPOP self-assembly and normal function. Given that many previously unaccounted-for cancer mutations are localized in these newly identified interfaces, we uncover molecular mechanisms underlying dysregulation of SPOP function, with effects ranging from gross structural changes to enhanced self-association, and heightened stability and activity.

Tumour cell-intrinsic CTLA4 regulates PD-L1 expression in non-small cell lung cancer

Cytotoxic T lymphocyte antigen 4 (CTLA4) and programmed cell death protein 1 (PD-1) are immune checkpoint proteins expressed in T cells. Although CTLA4 expression was found in multiple tumours including non-small cell lung cancer (NSCLC) tissues and cells, its function in tumour cells is unknown. Recently, PD-1 was found to be expressed in melanoma cells and to promote tumorigenesis. We found that CTLA4 was expressed in a subset of NSCLC cell lines and in a subgroup of cancer cells within the lung cancer tissues. We further found that in NSCLC cells, anti-CTLA4 antibody can induce PD-L1 expression, which is mediated by CTLA4 and the EGFR pathway involving phosphorylation of MEK and ERK. In CTLA4 knockout cells, EGFR knockout cells or in the presence of an EGFR tyrosine kinase inhibitor, anti-CTLA4 antibody was not able to induce PD-L1 expression in NSCLC cells. Moreover, anti-CTLA4 antibody promoted NSCLC cell proliferation in vitro and tumour growth in vivo in the absence of adaptive immunity. These results suggest that tumour cell-intrinsic CTLA4 can regulate PD-L1 expression and cell proliferation, and that anti-CTLA4 antibody, by binding to the tumour cell-intrinsic CTLA4, may result in the activation of the EGFR pathway in cancer cells.

Role of STAT3 in lung cancer

Lung cancer remains a challenging disease. It is responsible for the high cancer mortality rates in the US and worldwide. Elucidation of the molecular mechanisms operative in lung cancer is an important first step in developing effective therapies. Accumulating evidence over the last 2 decades suggests a critical role for Signal Transducer and Activator of Transcription 3 (STAT3) as a point of convergence for various signaling pathways that are dysregulated in the disease. In this review, we discuss possible molecular mechanisms involving STAT3 in lung tumorigenesis based on recent literature. We consider possible roles of STAT3 in cancer cell proliferation and survival, in the tumor immune environment, and in epigenetic regulation and interaction of STAT3 with other transcription factors. We also discuss the potential role of STAT3 in tumor suppression, which complicates strategies of targeting STAT3 in cancer therapy.

Mass gathering in Aqaba, Jordan, during Eid AI Adha, 2010

During the 5-day Eid Al Adha holiday, Aqaba is the site of one of the largest mass gatherings in Jordan. Public health concerns during this holiday included: food- and waterborne diseases, drowning, injuries by marine creatures, road traffic crashes, and pressure on emergency departments at hospitals. This cross-sectional study was carried out in Aqaba during the period 16-20 November 2010 and aimed to identify and prioritize the major public health risks and to overview the preparedness plans of the Health Directorate during previous Eid events in Aqaba. All related stakeholders participated in the study. An exploratory visit to Aqaba was made and an introductory workshop was conducted for participants. Relevant data were collected and compared with the figures for the week prior to the event. No food poisoning outbreaks were reported during the event. There was a 23% increase in emergency department attendance, a 33% increase in hospital admissions, and road traffic crashes increased by more than 300%. More males were affected than females.

The Nup155-mediated organisation of inner nuclear membrane proteins is independent of Nup155 anchoring to the metazoan nuclear pore complex

The nuclear envelope (NE), an important barrier between the nucleus and the cytoplasm, is composed of three structures: the outer nuclear membrane, which is continuous with the ER, the inner nuclear membrane (INM), which interfaces with chromatin, and nuclear pore complexes (NPCs), which are essential for the exchange of macromolecules between the two compartments. The NPC protein Nup155 has an evolutionarily conserved role in the metazoan NE formation; but the in vivo analysis of Nup155 has been severely hampered by the essential function of this protein in cell viability. Here, we take advantage of the hypomorphicity of RNAi systems and use a combination of protein binding and rescue assays to map the interaction sites of two neighbouring NPC proteins Nup93 and Nup53 on Nup155, and to define the requirements of these interactions in INM protein organization. We show that different parts of Drosophila Nup155 have distinct functions: the Nup155 β-propeller anchors the protein to the NPC, whereas the α-solenoid part of Nup155 is essential for the correct localisation of INM proteins lamin-B receptor (LBR) and otefin. Using chromatin extracts from semi-synchronized cells, we also provide evidence that the Nup155 α-solenoid has a chromatin-binding activity that is stronger at the end of mitosis. Our results argue that the role of Nup155 in INM protein localisation is not mediated through the NPC anchoring activity of the protein and suggest that regions other than Nup155 β-propeller are necessary for the targeting of proteins to the INM.

Chemical oxidation of ibuprofen in the presence of iron species at near neutral pH

The objective of this work was to evaluate the removal of ibuprofen (IBP) using the oxidants hydrogen peroxide (H(2)O(2)) and sodium persulfate (Na(2)S(2)O(8)). The ability of magnetite (Fe(3)O(4)) to activate persulfate (PS) and H(2)O(2) for the oxidation of IBP at near neutral pH was evaluated as well. The use of soluble Fe(2+) to activate H(2)O(2) and Na(2)S(2)O(8) was also investigated. H(2)O(2) and Na(2)S(2)O(8) were inactive during the sixty-minute experiments when used alone. However, activation using Fe(2+) increased the removal to 95% in the presence of H(2)O(2) (Fenton reaction) and 63% in the presence of Na(2)S(2)O(8) at pH 6.6. Chemical oxygen demand (COD) removal was also greater for Fenton oxidation (65%) than for iron-activated PS oxidation (25%). Activation of H(2)O(2) and PS by Fe(3)O(4) was only observed at a high oxidant concentration and over 48 h of reaction time. A second order rate kinetic constant was determined for H(2)O(2) (3.0∗10(-3) M(-1) s(-1)) and Na(2)S(2)O(8) (1.59∗10(-3) M(-1) s(-1)) in the presence of Fe(3)O(4). Finally, several of the degradation products formed during oxidation of IBP in the presence of H(2)O(2) and Na(2)S(2)O(8) (activated by Fe(2+)) were identified. These include oxalic acid, pyruvic acid, formic acid, acetic acid, 4-acetylbenzoic acid, 4-isobutylacetophenone (4-IBAP) and oxo-ibuprofen.

Distinct functions of the Drosophila Nup153 and Nup214 FG domains in nuclear protein transport

The phenylanine-glycine (FG)–rich regions of several nucleoporins both bind to nuclear transport receptors and collectively provide a diffusion barrier to the nuclear pores. However, the in vivo roles of FG nucleoporins in transport remain unclear. We have inactivated 30 putative nucleoporins in cultured Drosophila melanogaster S2 cells by RNA interference and analyzed the phenotypes on importin α/β−mediated import and CRM1-dependent protein export. The fly homologues of FG nucleoporins Nup358, Nup153, and Nup54 are selectively required for import. The FG repeats of Nup153 are necessary for its function in transport, whereas the remainder of the protein maintains pore integrity. Inactivation of the CRM1 cofactor RanBP3 decreased the nuclear accumulation of CRM1 and protein export. We report a surprisingly antagonistic relationship between RanBP3 and the Nup214 FG region in determining CRM1 localization and its function in protein export. Our data suggest that peripheral metazoan FG nucleoporins have distinct functions in nuclear protein transport events.

Recurrent pericardial effusion and pericardial tamponade in a patient with limited systemic sclerosis

We describe a patient with limited systemic sclerosis who presented with a large pericardial effusion with tamponade on echocardiogram, requiring pericardiocentesis to drain 1.2 l of fluid. She had a rapid re-accumulation of pericardial fluid and subsequently required a pericardial window. Although small pericardial effusions are common in patients with systemic sclerosis it is rare to have hemodynamic compromise. Previously reported large pericardial effusions have been seen in patients with pulmonary hypertension and renal failure however these were absent in our patient.

The nucleoporin Nup214 sequesters CRM1 at the nuclear rim and modulates NFkappaB activation in Drosophila

CRM1-mediated protein export is an important determinant of the nuclear accumulation of many gene regulators. Here, we show that the NFkappaB transcription factor Dorsal is a substrate of CRM1 and requires the nucleoporin Nup214 for its nuclear translocation upon signaling. Nup214 bound to CRM1 directly and anchored it to the nuclear envelope. In nup214 mutants CRM1 accumulated in the nucleus and NES-protein export was enhanced. Nup214 formed complexes with Nup88 and CRM1 in vivo and Nup214 protected Nup88 from degradation at the nuclear rim. In turn, Nup88 was sufficient for targeting the complex to the nuclear pores. Overexpression experiments indicated that Nup214 alone attracts a fraction of CRM1 to the nuclear envelope but does not interfere with NES-GFP export. By contrast, overexpression of the Nup214-Nup88 complex trapped CRM1 and Dorsal to cytoplasmic foci and inhibited protein export and immune response activation. We hypothesize that variation in levels of the Nup214-Nup88 complex at the pore changes the amount of NPC-bound CRM1 and influences the relative strength and duration of NFkappaB signaling responses.

The growing pre-mRNA recruits actin and chromatin-modifying factors to transcriptionally active genes

In the dipteran Chironomus tentans, actin binds to hrp65, a nuclear protein associated with mRNP complexes. Disruption of the actin-hrp65 interaction in vivo by the competing peptide 65-2CTS reduces transcription drastically, which suggests that the actin-hrp65 interaction is required for transcription. We show that the inhibitory effect of the 65-2CTS peptide on transcription is counteracted by trichostatin A, a drug that inhibits histone deacetylation. We also show that actin and hrp65 are associated in vivo with p2D10, an evolutionarily conserved protein with histone acetyltransferase activity that acts on histone H3. p2D10 is recruited to class II genes in a transcription-dependent manner. We show, using the Balbiani ring genes of C. tentans as a model system, that p2D10 is cotranscriptionally associated with the growing pre-mRNA. We also show that experimental disruption of the actin-hrp65 interaction by the 65-2CTS peptide in vivo results in the release of p2D10 from the transcribed genes, reduced histone H3 acetylation, and a lower level of transcription activity. Furthermore, antibodies against p2D10 inhibit run-on elongation. Our results suggest that actin, hrp65, and p2D10 are parts of a positive feedback mechanism that contributes to maintaining the active transcription state of a gene by recruiting HATs at the RNA level.

The Drosophila nucleoporin DNup88 localizes DNup214 and CRM1 on the nuclear envelope and attenuates NES-mediated nuclear export

Many cellular responses rely on the control of nucleocytoplasmic transport of transcriptional regulators. The Drosophila nucleoporin Nup88 is selectively required for nuclear accumulation of Rel proteins and full activation of the innate immune response. Here, we investigate the mechanisms underlying its role in nucleocytoplasmic transport. Nuclear import of an nuclear localization signal-enhanced green fluorescent protein (NLS-EGFP) reporter is not affected in DNup88 (members only; mbo) mutants, whereas the level of CRM1-dependent EGFP-nuclear export signal (EGFP-NES) export is increased. We show that the nuclear accumulation of the Drosophila Rel protein Dorsal requires CRM1. DNup88 binds to DNup214 and DCRM1 in vitro, and both proteins become mislocalized from the nuclear rim into the nucleus of mbo mutants. Overexpression of DNup88 is sufficient to relocalize DNup214 and CRM1 on the nuclear envelope and revert the mutant phenotypes. We propose that a major function of DNup88 is to anchor DNup214 and CRM1 on the nuclear envelope and thereby attenuate NES-mediated nuclear export.

Evidence for a posttranscriptional role of a TFIIICalpha-like protein in Chironomus tentans

We have cloned and sequenced a cDNA that encodes for a nuclear protein of 238 kDa in the dipteran Chironomus tentans. This protein, that we call p2D10, is structurally similar to the alpha subunit of the general transcription factor TFIIIC. Using immunoelectron microscopy we have shown that a fraction of p2D10 is located at sites of transcription, which is consistent with a possible role of this protein in transcription initiation. We have also found that a large fraction of p2D10 is located in the nucleoplasm and in the nuclear pore complexes. Using gel filtration chromatography and coimmunoprecipitation methods, we have identified and characterized two p2D10-containing complexes that differ in molecular mass and composition. The heavy p2D10-containing complex contains at least one other component of the TFIIIC complex, TFIIIC-epsilon. Based on its molecular mass and composition, the heavy p2D10-containing complex may be the Pol III holoenzyme. The light p2D10-containing complex contains RNA together with at least two proteins that are thought to be involved in mRNA trafficking, RAE1 and hrp65. The observations reported here suggest that this new TFIIIC-alpha-like protein is involved in posttranscriptional steps of premRNA metabolism in Chironomus tentans.

The Ct-RAE1 protein interacts with Balbiani ring RNP particles at the nuclear pore

RAE1 is an evolutionarily conserved protein that associates with both mRNPs and nucleoporins, and may bridge the interaction between mRNP export cargoes and the nuclear pore complex (NPC). However, the mechanism by which RAE1 functions in mRNA export is still unknown and the time point at which RAE1 interacts with the exported RNP has not been directly investigated. Here we have addressed this question in the Balbiani ring (BR) system of Chironomus tentans using immunoelectron microscopy. The RAE1 protein of C. tentans, Ct-RAE1, is 70% identical to human RAE1/mrnp41 (hRAE1) and is recognized by antibodies raised against hRAE1. As in vertebrate cells, Ct-RAE1 is concentrated at the nuclear envelope and also dispersed throughout the nuclear interior. Here we show that Ct-RAE1 does not bind to the BR particle either cotranscriptionally or in the nucleoplasm. Instead, the interaction between Ct-RAE1 and the exported BR particle occurs at the NPC. Moreover, the localization of Ct-RAE1 at the NPC is correlated with the presence of an exported RNP in the NPC. Finally, the anti-RAE1 antibody does not label the cytoplasmic side of BR particles in transit through the central channel, which indicates that Ct-RAE1 either remains anchored at the nuclear side of the NPC during translocation of the RNP through the central channel or becomes transiently associated with the RNP but is rapidly released into the cytoplasm.

Electron tomography reveals posttranscriptional binding of pre-mRNPs to specific fibers in the nucleoplasm

Using electron tomography, we have analyzed whether the Balbiani ring (BR) pre-mRNP particles in transit from the gene to the nuclear pore complex (NPC) are bound to any structure that could impair free diffusion through the nucleoplasm. We show that one-third of the BR particles are in contact with thin connecting fibers (CFs), which in some cases merge into large fibrogranular clusters. The CFs have a specific protein composition different from that of BR particles, as shown by immuno-EM. Moreover, we have identified hrp65 as one of the protein components of the CFs. The sequencing of hrp65 cDNA reveals similarities with hnRNP proteins and splicing factors. However, hrp65 is likely to have a different function because it does not bind to nascent pre-mRNA and is not part of the pre-mRNP itself. Taken together, our observations indicate that pre-mRNPs are not always freely diffusible in the nucleoplasm but interact with fibers of specific structure and composition, which implies that some of the posttranscriptional events that the pre-mRNPs undergo before reaching the NPC occur in a bound state.

Transient and stable electrotransformations of intact black Mexican sweet maize cells are obtained after preplasmolysis

When interested in plant cell transformation, the cell wall is often considered as a barrier to DNA transfer, which is only overcome by wounding or wall degrading enzymes. In this work, we demonstrate that cell plasmolysis before electropulsation is an efficient approach to DNA delivery into intact plant cells. Using such a method, transient expression (β-glucuronidase and chloramphenicol acetyltransferase) and stable expression (phosphinotricin acetyltransferase) of exogenous genes are obtained in intact black Mexican sweet maize cells.

Electropermeabilization of intact maize cells induces an oxidative stress

By applying electric field pulses through cell suspensions, cell membranes can be permeabilized transiently, giving free access to the cytosol. Electropulsation is now routinely used in cell biology when introducing various molecules such as proteins and nucleic acids into the cell. But the molecular and cellular bases of cell electropermeabilization are still unclear. In the present study, we observed that electropermeabilization of intact black Mexican sweet (BMS) maize cells induces a generation of oxygen species (oxidative jump). Using the chemiluminescent probe lucigenin, we have shown that the electro-induced chemiluminescent response depends on the level of the stress factor as shown by its dependence on the electric parameters (electric field intensity, duration, and number of pulses). While the electroinduced cell permeabilization has a short life, the oxidative jump that is triggered by this electropermeabilization is a much longer-lived response. The electroinduced loss in viability is linearly correlated to permeabilization. However, there is no correlation between the oxidative jump and the loss in viability. The modulation of oxygen species electroinduction by antioxidant products (dimethylsulfoxide, sodium L-ascorbate, and glutathione) does not lead to an increase in cell viability. Such results are different to those observed with mammalian cells and indicate that even if the same phenomenon is observed with mammalian cells and indicate that even if the same phenomenon is observed when pulsing mammalian or intact plant cells, the associated metabolic response is not the same.

Closure of a persistent femoral artery pseudoaneurysm complicating coronary angioplasty using the femostop compression device and direct ultrasound visualization

Nonsurgical closure of femoral artery pseudoaneurysm (PSA), using ultrasound guidance and compression with the ultrasound probe or a C-clamp, has been previously described. We report a patient in whom a different compression device was used (the Femostop) which also allows direct ultrasound visualization of the PSA and femoral vessels at the site of compression. This resulted in adequate PSA with preservation of flow in both artery and vein throughout the procedure.

Complications of cardiac catheterization, coronary angiography, and coronary interventions

Cardiac catheterization and coronary angiography have evolved, especially after the advent of percutaneous coronary interventions. Although older patients with more advanced disease are being studied, the overall rate of complications has not dramatically increased and the spectrum of complications has somewhat changed to select the more acute nature of the procedures performed. Careful prophylactic measures such as anticoagulation, ischemia prevention, blood pressure control, hydration as well as the availability of defibrillation and pharmacologic and mechanical means of circulatory support have helped minimize these complications and improve outcome.

Frequency of coronary artery disease and left ventricle dysfunction in cocaine users

To evaluate the spectrum of coronary artery disease (CAD) in cocaine users, coronary angiograms obtained from 33 patients (26 men [79%] and 7 women [21%], mean age 37 years) with history of cocaine use and cardiac symptoms were retrospectively reviewed. Clinical indications for coronary angiograms included chest pain (n = 28), congestive failure (n = 4) and complete heart block (n = 1). Coronary angiograms were reviewed independently by 2 angiographers unaware of patient's clinical status. Thirteen patients (40%) had normal coronary angiograms, and 20 (60%) had CAD; 7 (21%) had mild CAD (less than or equal to 70% diameter stenosis), and 13 (40%) had significant CAD (greater than 70% diameter stenosis). Of 13 patients with significant CAD, 7 had 1-vessel, 4 had 2-vessel and 2 had 3-vessel CAD. There was enzymatic evidence of myocardial infarction in 12 of 33 patients (36%); all 12 had CAD (10 with significant and 2 with mild CAD). Mean age and number of risk factors (serum total cholesterol, cigarette smoking, systemic hypertension, diabetes mellitus, family history of CAD, and obesity) in patients with CAD (mild or significant) and with normal coronary angiograms were not statistically different. Left ventricular ejection fraction was normal in 15 patients (45%) and depressed in 18 (55%). All patients with CAD and low ejection fractions (n = 12) had regional wall motion abnormalities, whereas all those with normal coronary arteries and low ejection fraction (n = 6) had global hypokinesia.

Intracoronary urokinase as an adjunct to percutaneous transluminal coronary angioplasty in patients with complex coronary narrowings or angioplasty-induced complications

The effectiveness of intracoronary urokinase infusion as an adjunct to percutaneous transluminal coronary angioplasty (PTCA) was studied in 50 patients who underwent angioplasty for complex coronary narrowings or had thromboembolic complications during PTCA (29 [58%] men, 3 [6%] stable and 37 [74%] unstable angina, and 16 [32%] prior coronary bypass surgery). The primary indications for intracoronary urokinase infusion were intracoronary thrombus in 27 patients (54%), distal coronary embolization in 9 (18%), and abrupt reclosure in 14 (28%). Urokinase was infused in a mean (+/- standard deviation) dosage of 399,000 +/- 194,000 IU (range 150,000 to 1,000,000) at an average rate of 5,000 to 20,000 IU/min. Angiographic success was achieved in 43 patients (86%). Complications included the need for urgent bypass surgery in 3 patients, Q-wave myocardial infarction in 2, and non-Q-wave myocardial infarction in 12 (8 of whom had peak creatine kinase less than twice the upper normal limit). The incidence of myocardial infarction was significantly higher in patients with vein grafts (69%) than in those with PTCA of native vessels (14%). Two patients died (1 massive gastrointestinal necrosis 24 hours after angioplasty, and 1 after urgent bypass surgery). Mean (+/- standard deviation) fibrinogen levels were 355 +/- 73 mg/dl before urokinase infusion, and 361 +/- 70, twelve hours afterward. Three patients had local bleeding, but no transfusions were needed. It is concluded that intracoronary urokinase is a safe and effective adjunct to PTCA in patients with associated thrombi and may improve the success rate in angioplasty complicated by thrombus formation.

Intracoronary recombinant tissue-type plasminogen activator in unstable angina: a pilot angiographic study

The effectiveness of intracoronary (IC) recombinant thromboplastin activator (rt-PA) was prospectively evaluated in seven patients with unstable angina and complex angiographic lesions or intracoronary filling defects (ICFD). There were four men and three women, with a mean age of 60 years. Three patients had multivessel disease and all patients had rest angina; none had evolving myocardial infarction. All patients were pretreated with aspirin and were given heparin. IC rt-PA was infused at the rate of 1 mg/min to a total of 50 mg, and angiographic changes were observed every 15 minutes. At 50 minutes, angiographic improvement was seen in two patients (28%), one of whom had complete and one of whom had partial resolution of ICFD. In two patients (28%) there was no change in the lesion, and three patients (42%) had worsening of the lesion appearance. In two of the latter, paradoxical closure was observed at the end of the infusion, and was treated successfully with ad hoc emergency angioplasty. This pilot study suggests that IC rt-PA at the dosage used may have variable effects on complex coronary lesions associated with unstable angina, and this may be of relevance in further trials evaluating IC thrombolysis in unstable coronary ischemic syndromes.

Application of coronary angioplasty to the septal perforator arteries

Significant coronary artery disease affecting the septal perforator arteries can cause anginal pain, rhythm disturbances, or septal infarction. However, since these vessels are usually inaccessible to coronary bypass surgery, there is a tendency among angiographers and angioplasters to overlook lesions of the septal perforator arteries. Our experience suggests that if medical treatment is not sufficient to treat clinical manifestations resulting from septal perforator disease, then coronary angioplasty can be considered a therapeutic alternative for revascularization. We herein present 11 patients who underwent coronary angioplasty of a major septal artery and discuss angiographic and technical aspects of the procedure.

Effect of atherosclerosis and hypertension on arterial epistaxis

Eye fundus examination in twenty cases of hypertensive nose bleeding was carried out to evaluate the effect of hypertension and atherosclerosis on epistaxis. Arteriolar attenuation, atherosclerosis and venous congestion were detected in most of the cases. None showed haemorrhages or exudates. Hypertension and atherosclerosis seem to maintain and increase the severity of epistaxis, once it has been initiated by other factors.