Comparison of Treatment Modalities in Postirradiation Carotid Blowout Syndrome: A Multicenter Retrospective Review.

BACKGROUND: Carotid blowout syndrome (CBS) is not uncommon in our locality, where head and neck cancers, especially nasopharyngeal carcinoma, are prevalent. Traditionally, CBS has resulted in high morbidity and mortality. The treatment paradigm has evolved from open surgery to endovascular interventions, and each treatment modality has its merits and drawbacks. In the present study, we investigated the outcomes of different treatment modalities for postirradiation CBS. METHODS: We performed a 10-year multicenter retrospective review of the outcomes after endovascular trapping, flow diverters, and bypass surgery from 2009 to 2019. RESULTS: A total of 53 patients with 60 blowouts were included in the present study. Of the 60 blowout cases, 25 were in the flow diverter group, 27 in the endovascular trapping group, and 8 in the bypass group. The mean survival was 32.2 months, with patient age affecting overall survival (P = 0.002). The stroke rate affected the 3- and 6-month functional outcomes (odds ratio, 7.388 and 6.353; P = 0.008 and P = 0.014, respectively). Of the 24 cases in the flow diverter group, 96% had achieved immediate hemostasis, with a rebleeding rate of 20% (P = 0.009). No rebleeding had occurred with endovascular trapping or bypass. The stroke rate in the endovascular trapping, flow diverter, and bypass groups was 25.9%, 20%, and 12.5%, respectively (P = 0.696). CONCLUSIONS: Our results have shown that endovascular trapping is the first-line treatment of CBS. For patients with contraindications to endovascular trapping, the flow diverter is an alternative. For patients who have undergone flow diversion alone, definitive treatment such as bypass surgery might be indicated for selected patients to minimize the risk of rebleeding. After endovascular trapping, surgical bypass might be considered for selected patients with a higher risk of stroke.

Pseudoaneurysm formation and rupture after stereotactic radiotherapy for cerebral arteriovenous malformation: a case report and review of literature.

We report a rare delayed complication of de novo pseudoaneurysm formation and rupture after stereotactic radiotherapy for cerebral arteriovenous malformation. The patient presented with intracerebral haemorrhage due to rupture of a pseudoaneurysm in the previously irradiated field, which was excised for histological examination. The literature was reviewed for similar cases.

HPV episome levels are potently decreased by pyrrole-imidazole polyamides.

Human papillomavirus (HPV) causes cervical cancer and other hyperproliferative diseases. There currently are no approved antiviral drugs for HPV that directly decrease viral DNA load and that have low toxicity. We report the potent anti-HPV activity of two N-methylpyrrole-imidazole polyamides of the hairpin type, polyamide 1 (PA1) and polyamide 25 (PA25). Both polyamides have potent anti-HPV activity against three different genotypes when tested on cells maintaining HPV episomes. The compounds were tested against HPV16 (in W12 cells), HPV18 (in Ker4-18 cells), and HPV31 (in HPV31 maintaining cells). From a library of polyamides designed to recognize AT-rich DNA sequences such as those in or near E1 or E2 binding sites of the HPV16 origin of replication (ori), four polyamides were identified that possessed apparent IC(50)s≤150nM with no evidence of cytotoxicity. We report two highly-active compounds here. Treatment of epithelia engineered in organotypic cultures with these compounds also causes a dose-dependent loss of HPV episomal DNA that correlates with accumulation of compounds in the nucleus. Bromodeoxyuridine (BrdU) incorporation demonstrates that DNA synthesis in organotypic cultures is suppressed upon compound treatment, correlating with a loss of HPV16 and HPV18 episomes. PA1 and PA25 are currently in preclinical development as antiviral compounds for treatment of HPV-related disease, including cervical dysplasia. PA1, PA25, and related polyamides offer promise as antiviral agents and as tools to regulate HPV episomal levels in cells for the study of HPV biology. We also report that anti-HPV16 activity for Distamycin A, a natural product related to our polyamides, is accompanied by significant cellular toxicity.

Results of excision of cerebral radionecrosis: experience in patients treated with radiation therapy for nasopharyngeal carcinoma.

OBJECT: In theory, the purpose of the treatment of cerebral radionecrosis (CRN), a nonneoplastic condition, is to minimize loss of brain function by preventing the progression and reversing some of the processes of CRN. In a practical sense, factors for achieving this purpose may include the following: removal of a CRN lesion that is causing mass effect, control of brain edema, prevention of recurrence of CRN lesions, minimization of adverse effects from treatments, and achievement of reasonably long and good-quality survivals. Based on these practical issues, the authors performed a retrospective study to evaluate the results of excision for the treatment of CRN. METHODS: The authors retrospectively reviewed the results of excision of CRN lesions in a group of patients with temporal lobe CRN due to radiotherapy for nasopharyngeal carcinoma. Patients who had undergone surgery at the authors' institution between January 1998 and November 2008 were analyzed. Surgical results were evaluated by assessing postoperative resolution of brain edema, recurrence of temporal lobe CRN, surgery-related complications, and postoperative functional status and survival. RESULTS: Twenty-four patients were included (age range 39-69 years; in 23 patients nasopharyngeal carcinoma was in remission). All patients underwent craniotomy for excision of the contrast-enhancing region. The indications for operation were temporal lobe CRN lesions with a mass-occupying effect beyond the temporal lobe. There were 32 craniotomies in all (mean postoperative follow-up 40 months). It was found that brain edema resolved rapidly postoperatively. The recurrence and reoperation rates were 6.3 and 3.1%, respectively. There were no surgery-related deaths. The median survival was 72 months, and 67% of the patients had a Karnofsky Performance Scale score of > or = 70% at the time of their last follow-up. CONCLUSIONS: In a specific group of patients with CRN of the temporal lobe in whom the CRN lesions were causing a mass-occupying effect beyond the temporal lobe, excision of the contrast-enhancing region was safe and could achieve prompt resolution of brain edema and a low incidence of recurrence of CRN.

Identification of an ADAMTS-4 cleavage motif using phage display leads to the development of fluorogenic peptide substrates and reveals matrilin-3 as a novel substrate.

ADAMTS-4 and ADAMTS-5 are aggrecanases responsible for the breakdown of cartilage aggrecan in osteoarthritis. Multiple ADAMTS-4 cleavage sites have been described in several matrix proteins including aggrecan, versican, and brevican, but no concise predictive cleavage motif has been identified for this protease. By screening a 13-mer peptide library with a diversity of 10(8), we have identified the ADAMTS-4 cleavage motif E-(AFVLMY)-X(0,1)-(RK)-X(2,3)-(ST)-(VYIFWMLA), with Glu representing P1. Several 13-mer peptides containing this motif, including DVQEFRGVTAVIR and HNEFRQRETYMVF, were shown to be substrates for ADAMTS-4. These peptides were found to be specific substrates for ADAMTS-4 as they were not cleaved by ADAMTS-5. Modification of these peptides with donor (6-FAM) and acceptor (QSY-9) molecules resulted in the development of fluorescence-based substrates with a Km of approximately 35 microM. Furthermore, the role of Glu at P1 and Phe at P1' in binding and catalysis was studied by exploring substitution of these amino acids with the D-isomeric forms. Substitution of P1 with dGlu was tolerable for binding, but not catalysis, whereas substitution of P1' with dPhe precluded both binding and catalysis. Similarly, replacement of Glu with Asp at P1 abolished recognition and cleavage of the peptide. Finally, BLAST results of the ADAMTS-4 cleavage motif identified matrilin-3 as a new substrate for ADAMTS-4. When tested, recombinant ADAMTS-4 effectively cleaved intact matrilin-3 at the predicted motif at Glu435/Ala436 generating two species of 45 and 5 kDa.

Alpha2-macroglobulin is a novel substrate for ADAMTS-4 and ADAMTS-5 and represents an endogenous inhibitor of these enzymes.

Osteoarthritis is characterized by the loss of aggrecan and collagen from the cartilage extracellular matrix. The proteinases responsible for the breakdown of cartilage aggrecan include ADAMTS-4 (aggrecanase 1) and ADAMTS-5 (aggrecanase 2). Post-translational inhibition of ADAMTS-4/-5 activity may be important for maintaining normal homeostasis of aggrecan metabolism, and thus, any disruption to this inhibition could lead to accelerated aggrecan breakdown. To date TIMP-3 (tissue inhibitor of matrix metalloproteinases-3) is the only endogenous inhibitor of ADAMTS-4/-5 that has been identified. In the present studies we identify alpha(2)-macroglobulin (alpha(2)M) as an additional endogenous inhibitor of ADAMTS-4 and ADAMTS-5. alpha(2)M inhibited the activity of both ADAMTS-4 and ADAMTS-5 in a concentration-dependent manner, demonstrating 1:1 stoichiometry with second-order rate constants on the order of 10(6) and 10(5) m(-1) s(-1), respectively. Inhibition of the aggrecanases was mediated by proteolysis of the bait region within alpha(2)M, resulting in physical entrapment of these proteinases. Both ADAMTS-4 and ADAMTS-5 cleaved alpha(2)M at Met(690)/Gly(691), representing a novel proteinase cleavage site within alpha(2)M and a novel site of cleavage for ADAMTS-4 and ADAMTS-5. Finally, the use of the anti-neoepitope antibodies to detect aggrecanase-generated alpha(2)M-fragments in synovial fluid was investigated and found to be uninformative.

Examination of the kinetic mechanism of mitogen-activated protein kinase activated protein kinase-2.

The kinetic mechanism of mitogen-activated protein kinase activated protein kinase-2 (MAPKAPK2) was investigated using a peptide (LKRSLSEM) based on the phosphorylation site found in serum response factor (SRF). Initial velocity studies yielded a family of double-reciprocal lines that appear parallel and indicative of a ping-pong mechanism. The use of dead-end inhibition studies did not provide a definitive assignment of a reaction mechanism. However, product inhibition studies suggested that MAPKAPK2 follows an ordered bi-bi kinetic mechanism, where ATP must bind to the enzyme prior to the SRF-peptide and the phosphorylated product is released first, followed by ADP. In agreement with these latter results, surface plasmon resonance measurements demonstrate that the binding of the inhibitor peptide to MAPKAPK2 requires the presence of ATP. Furthermore, competitive inhibitors of ATP, adenosine 5'-(beta,gamma-imino)triphosphate (AMPPNP) and a staurosporine analog (K252a), can inhibit this ATP-dependent binding providing further evidence that the peptide substrate binds preferably to the E:ATP complex.

A decaepitope polypeptide primes for multiple CD8+ IFN-gamma and Th lymphocyte responses: evaluation of multiepitope polypeptides as a mode for vaccine delivery.

Proteins are generally regarded as ineffective immunogens for CTL responses. We synthesized a 100-mer decaepitope polypeptide and tested its capacity to induce multiple CD8(+) IFN-gamma and Th lymphocyte (HTL) responses in HLA transgenic mice. Following a single immunization in the absence of adjuvant, significant IFN-gamma in vitro recall responses were detected for all epitopes included in the construct (six A2.1-, three A11-restricted CTL epitopes, and one universal HTL epitope). Immunization with truncated forms of the decaepitope polypeptide was used to demonstrate that optimal immunogenicity was associated with a size of at least 30-40 residues (3-4 epitopes). Solubility analyses of the truncated constructs were used to identify a correlation between immunogenicity for IFN-gamma responses and the propensity of these constructs to form particulate aggregates. Although the decaepitope polypeptide and a pool of epitopes emulsified in IFA elicited similar levels of CD8(+) responses using fresh splenocytes, we found that the decaepitope polypeptide more effectively primed for in vitro recall CD8(+) T cell responses. Finally, immunogenicity comparisons were also made between the decaepitope polypeptide and a corresponding gene encoding the same polypeptide delivered by naked DNA immunization. Although naked DNA immunization induced somewhat greater direct ex vivo and in vitro recall responses 2 wk after a single immunization, only the polypeptide induced significant in vitro recall responses 6 wk following the priming immunization. These studies support further evaluation of multiepitope polypeptide vaccines for induction of CD8(+) IFN-gamma and HTL responses.