Isolation and Characterization of a Novel Alpha-Hemolytic Streptococcus spp. from the Oral Cavity and Blood of Septicemic Periparturient Immunodeficient Mice

MISTRG is an immunodeficient mouse strain that expresses multiple human cytokines that support hematopoietic stem cell maintenance and myelopoiesis. While establishing a breeding colony of MISTRG mice in a dedicated barrier room, 6 cases of death or disease occurred in pregnant or postpartum mice. Clinically, this manifested as hunched posture, dyspnea, and 1 case of emaciation with ataxia. Pathologic analysis of 7 mice revealed multisystemic necrosuppurative inflammation variably affecting the uterus and placenta, joints, meninges, inner and middle ears, kidneys, and small intestine. Bacteria cultured from the blood of septic mice were identified with 89% probability by the Vitek 2 identification system as Streptococcus sanguinus with atypical biochemical parameters; the API 20E/NE system fully differentiated the isolates as a novel Streptococcus species. MALDI Biotyper-based mass spectrometry also indicated that the phenotype represented a novel Streptococcus spp. Sequencing revealed that the full-length 16S rRNA gene identity was below 97% with known Streptococcus species, including the 2 closest species Streptococcus acidominimus and Streptococcus azizii. We propose the name Streptococcus murisepticum spp. nov to our novel isolates. All male mice in this colony remained healthy despite their association with diseased female mice. Overall, 19% of the colony carried the novel Streptococcus in their oral cavity, but it could not be detected in feces. The organism was sensitive to amoxicillin, which was administered via drinking water throughout pregnancy and weaning to establish a colony of pathogen-negative future breeders. The colony remained disease-free and culture-negative for Streptococcus murisepticum spp. nov after treatment with amoxicillin. We suspect that oral colonization of MISTRG mice with the novel Streptococcus species and its associated unique pathology in periparturient mice is potentially the principal cause of loss of this strain at several institutions. Therefore, screening the oral cavity for α-hemolytic streptococci followed by targeted antibiotic treatment may be necessary when establishing MISTRG and allied immunodeficient mouse strains.

Isolation and Characterization of a Novel Alpha-Hemolytic Streptococcus spp. from the Oral Cavity and Blood of Septicemic Periparturient Immunodeficient Mice

MISTRG is an immunodeficient mouse strain that expresses multiple human cytokines that support hematopoietic stem cell maintenance and myelopoiesis. While establishing a breeding colony of MISTRG mice in a dedicated barrier room, 6 cases of death or disease occurred in pregnant or postpartum mice. Clinically, this manifested as hunched posture, dyspnea, and 1 case of emaciation with ataxia. Pathologic analysis of 7 mice revealed multisystemic necrosuppurative inflammation variably affecting the uterus and placenta, joints, meninges, inner and middle ears, kidneys, and small intestine. Bacteria cultured from the blood of septic mice were identified with 89% probability by the Vitek 2 identification system as Streptococcus sanguinuswith atypical biochemical parameters; the API 20E/NE system fully differentiated the isolates as a novel Streptococcusspecies. MALDI Biotyper-based mass spectrometry also indicated that the phenotype represented a novel Streptococcusspp. Sequencing revealed that the full-length 16S rRNA gene identity was below 97% with known Streptococcus species, including the 2 closest species Streptococcus acidominimus and Streptococcus azizii. We propose the name Streptococcus murisepticum spp. nov to our novel isolates. All male mice in this colony remained healthy despite their association with diseased female mice. Overall, 19% of the colony carried the novel Streptococcus in their oral cavity, but it could not be detected in feces. The organism was sensitive to amoxicillin, which was administered via drinking water throughout pregnancy and weaning to establish a colony of pathogen-negative future breeders. The colony remained disease-free and culture-negative for Streptococcus murisepticum spp. nov after treatment with amoxicillin. We suspect that oral colonization of MISTRG mice with the novel Streptococcus species and its associated unique pathology in periparturient mice is potentially the principal cause of loss of this strain at several institutions. Therefore, screening the oral cavity for α-hemolytic streptococci followed by targeted antibiotic treatment may be necessary when establishing MISTRG and allied immunodeficient mouse strains.

Transkingdom Interactions Important for the Pathogenesis of Human Viruses

The bacterial, fungal, and helminthic species that comprise the microbiome of the mammalian host have profound effects on health and disease. Pathogenic viruses must contend with the microbiome during infection and likely have evolved to exploit or evade the microbiome. Both direct interactions between the virions and the microbiota and immunomodulation and tissue remodeling caused by the microbiome alter viral pathogenesis in either host- or virus-beneficial ways. Recent insights from in vitro and murine models of viral pathogenesis have highlighted synergistic and antagonistic, direct and indirect interactions between the microbiome and pathogenic viruses. This review will focus on the transkingdom interactions between human gastrointestinal and respiratory viruses and the constituent microbiome of those tissues.

Influences of Vitamin A on Vaccine Immunogenicity and Efficacy

Vitamin A deficiencies and insufficiencies are widespread in developing countries, and may be gaining prevalence in industrialized nations. To combat vitamin A deficiency (VAD), the World Health Organization (WHO) recommends high-dose vitamin A supplementation (VAS) in children 6–59 months of age in locations where VAD is endemic. This practice has significantly reduced all-cause death and diarrhea-related mortalities in children, and may have in some cases improved immune responses toward pediatric vaccines. However, VAS studies have yielded conflicting results, perhaps due to influences of baseline vitamin A levels on VAS efficacy, and due to cross-regulation between vitamin A and related nuclear hormones. Here we provide a brief review of previous pre-clinical and clinical data, showing how VAD and VAS affect immune responses, vaccines, and infectious diseases. We additionally present new results from a VAD mouse model. We found that when VAS was administered to VAD mice at the time of vaccination with a pneumococcal vaccine (Prevnar-13), pneumococcus (T4)-specific antibodies were significantly improved. Preliminary data further showed that after challenge with Streptococcus pneumoniae, all mice that had received VAS at the time of vaccination survived. This was a significant improvement compared to vaccination without VAS. Data encourage renewed attention to vitamin A levels, both in developed and developing countries, to assist interpretation of data from vaccine research and to improve the success of vaccine programs.

The Transcriptional landscape of Streptococcus pneumoniae TIGR4 reveals a complex operon architecture and abundant riboregulation critical for growth and virulence

Efficient and highly organized regulation of transcription is fundamental to an organism’s ability to survive, proliferate, and quickly respond to its environment. Therefore, precise mapping of transcriptional units and understanding their regulation is crucial to determining how pathogenic bacteria cause disease and how they may be inhibited. In this study, we map the transcriptional landscape of the bacterial pathogen Streptococcus pneumoniae TIGR4 by applying a combination of high-throughput RNA-sequencing techniques. We successfully map 1864 high confidence transcription termination sites (TTSs), 790 high confidence transcription start sites (TSSs) (742 primary, and 48 secondary), and 1360 low confidence TSSs (74 secondary and 1286 primary) to yield a total of 2150 TSSs. Furthermore, our study reveals a complex transcriptome wherein environment-respondent alternate transcriptional units are observed within operons stemming from internal TSSs and TTSs. Additionally, we identify many putative cis-regulatory RNA elements and riboswitches within 5’-untranslated regions (5’-UTR). By integrating TSSs and TTSs with independently collected RNA-Seq datasets from a variety of conditions, we establish the response of these regulators to changes in growth conditions and validate several of them. Furthermore, to demonstrate the importance of ribo-regulation by 5’-UTR elements for in vivo virulence, we show that the pyrR regulatory element is essential for survival, successful colonization and infection in mice suggesting that such RNA elements are potential drug targets. Importantly, we show that our approach of combining high-throughput sequencing with in vivo experiments can reconstruct a global understanding of regulation, but also pave the way for discovery of compounds that target (ribo-)regulators to mitigate virulence and antibiotic resistance.

The canonical relationship between a bacterial operon and the mRNA transcript produced from the operon has become significantly more complex as numerous regulatory mechanisms that impact the stability, translational efficiency, and early termination rates for mRNA transcripts have been described. With the rise of antibiotic resistance, these mechanisms offer new potential targets for antibiotic development. In this study we used a combination of high-throughput sequencing technologies to assess genome-wide transcription start and stop sites, as well as determine condition specific global transcription patterns in the human pathogen Streptococcus pneumoniae. We find that the majority of multi-gene operons have alternative start and stop sites enabling condition specific regulation of genes within the same operon. Furthermore, we identified many putative RNA regulators that are widespread in the S. pneumoniae pan-genome. Finally, we show that separately collected RNA-Seq data enables identification of conditional triggers for regulatory RNAs, and experimentally demonstrate that our approach may be used to identify drug-able RNA targets by establishing that pyrR RNA functionality is critical for successful S. pneumoniae mouse colonization and infection. Thus, our study not only uses genome-wide high-throughput approaches to identify putative RNA regulators, but also establishes the importance of such regulators in S. pneumoniae virulence.

713. Vancomycin Heteroresistance in Coagulase Negative Staphylococci (CoNS) Causing Central Line-Associated Bloodstream Infection (CLABSI) in Pediatric Patients with Leukemia

Background

Methods

Results

Conclusion

Disclosures

1771. Gut Resistome Changes in Response to Prophylactic Antibiotic Administration During Chemotherapy in Children With Acute Lymphoblastic Leukemia

Background

Antibiotic resistance harbored in gut microbiome contributes to the emergence of multi–drug-resistant organisms (MDRO). Pediatric leukemia patients typically receive extensive antibiotics and are at higher risk for infection due to MDRO.

Methods

A prospective cohort of children (n = 242) with acute lymphoblastic leukemia self-collected stool samples at diagnosis and after induction chemothearpy. A third of patients (n = 69) underwent protocol-driven antibiotic prophylaxis: Levofloxacin (LV) given once neutropenia develops. With neutropenic fever patients on prophylaxis stopped LV and all patients received cefepime. Using metagenomic sequencing, we identified bacterial community composition and after alignment to the Comprehensive Antibiotic Resistance Database were able to determine the presence of bacterial resistance genes in 168 stool samples from 49 patients.

Results

Expected changes in the community composition were discovered with LV prophylaxis, including the loss of many Enterobacteriaceae and Enterococcaceae species, offset by increases in Bacteroides species. Unexpectedly, LV prophylaxis reduced the acquisition of VanA cluster of vancomycin resistance genes and did not increase acquisition of β-lactamase or fluoroquinolone (FQ) resistance gene families.

Conclusion

LV prophylaxis during leukemia treatment imparts predictable changes in gut bacterial communities but counter intuitively decreases antibiotic resistance in the gut microbiome reservoir. The reduction in VanA cluster of genes is likely due to depletion of Enterococcaceae species via direct killing or loss of synergistic partners. The lack of increase in target (FQ) or off-target resistance suggests that prophylaxis altered community selective pressures or prophylaxis drug concentrations were sufficient to limit the outgrowth of resistant mutants.

Disclosures

J. Wolf, Karius Inc.: Investigator, Research support.

Pneumococcal neuraminidase activates TGF-β signalling

Neuraminidase A (NanA) is an important virulence factor that is anchored to the pneumococcal cell wall and cleaves sialic acid on host substrates. We noted that a secreted allele of NanA was over-represented in invasive pneumococcal isolates and promoted the development of meningitis when swapped into the genome of non-meningitis isolates replacing cell wall-anchored NanA. Both forms of recombinant NanA directly activated transforming growth factor (TGF)-β, increased SMAD signalling and promoted loss of endothelial tight junction ZO-1. However, in assays using whole bacteria, only the cell-bound NanA decreased expression of ZO-1 and showed NanA dependence of bacterial invasion of endothelial cells. We conclude that NanA secretion versus retention on the cell surface does not influence neurotropism of clinical isolates. However, we describe a new NanA-TGF-β signalling axis that leads to decreased blood-brain barrier integrity and enhances bacterial invasion.

Saccharomyces cerevisiae-derived virus-like particle parvovirus B19 vaccine elicits binding and neutralizing antibodies in a mouse model for sickle cell disease

Parvovirus B19 infections are typically mild in healthy individuals, but can be life threatening in individuals with sickle cell disease (SCD). A Saccharomyces cerevisiae-derived B19 VLP vaccine, now in pre-clinical development, is immunogenic in wild type mice when administered with the adjuvant MF59. Because SCD alters the immune response, we evaluated the efficacy of this vaccine in a mouse model for SCD. Vaccinated mice with SCD demonstrated similar binding and neutralizing antibody responses to those of heterozygous littermate controls following a prime-boost-boost regimen. Due to the lack of a mouse parvovirus B19 challenge model, we employed a natural mouse pathogen, Sendai virus, to evaluate SCD respiratory tract responses to infection. Normal mucosal and systemic antibody responses were observed in these mice. Results demonstrate that mice with SCD can respond to a VLP vaccine and to a respiratory virus challenge, encouraging rapid development of the B19 vaccine for patients with SCD.

Promiscuous signaling by a regulatory system unique to the pandemic PMEN1 pneumococcal lineage

Streptococcus pneumoniae (pneumococcus) is a leading cause of death and disease in children and elderly. Genetic variability among isolates from this species is high. These differences, often the product of gene loss or gene acquisition via horizontal gene transfer, can endow strains with new molecular pathways, diverse phenotypes, and ecological advantages. PMEN1 is a widespread and multidrug-resistant pneumococcal lineage. Using comparative genomics we have determined that a regulator-peptide signal transduction system, TprA2/PhrA2, was acquired by a PMEN1 ancestor and is encoded by the vast majority of strains in this lineage. We show that TprA2 is a negative regulator of a PMEN1-specific gene encoding a lanthionine-containing peptide (lcpA). The activity of TprA2 is modulated by its cognate peptide, PhrA2. Expression of phrA2 is density-dependent and its C-terminus relieves TprA2-mediated inhibition leading to expression of lcpA. In the pneumococcal mouse model with intranasal inoculation, TprA2 had no effect on nasopharyngeal colonization but was associated with decreased lung disease via its control of lcpA levels. Furthermore, the TprA2/PhrA2 system has integrated into the pneumococcal regulatory circuitry, as PhrA2 activates TprA/PhrA, a second regulator-peptide signal transduction system widespread among pneumococci. Extracellular PhrA2 can release TprA-mediated inhibition, activating expression of TprA-repressed genes in both PMEN1 cells as well as another pneumococcal lineage. Acquisition of TprA2/PhrA2 has provided PMEN1 isolates with a mechanism to promote commensalism over dissemination and control inter-strain gene regulation.

Streptococcus pneumoniae (pneumococcus), an important human pathogen, exhibits a dual lifestyle featuring asymptomatic colonization of the host on the one hand as well as infliction of severe local and systemic disease on the other. In pneumococcal strains, differences in gene possession often lead to varied phenotypic outcomes. Epidemiologically, pandemic strains of the PMEN1 lineage show high prevalence in disease as well as carriage, posing an interesting question on the composition and function of the genomic toolkit that leads to their widespread success. Here, we characterize TprA2/PhrA2 sensory system, a genomic region acquired exclusively by the PMEN1 strains. The system consists of a regulator-peptide pair that was horizontally acquired into PMEN1 along with its regulatory circuitry. The regulatory peptide PhrA2 is receptive to cell density of PMEN1 cells and is an example of elegant communication signaling between bacterial cells. The regulatory influence of PhrA2 extends beyond PMEN1 cells such that it controls genes of a widespread signaling system and virulence regulon in non-PMEN1 strains. This work contributes to the knowledge of peptide-communication signals in pneumococcus and further adds a novel mechanism by which an ecologically successful linage may modify the transcriptomic and functional landscape of a multi-strain pneumococcal community.

B cell response to parvovirus B19 despite abnormal splenic architecture and cytokine/chemokine profiles in patients and animal models with sickle cell disease (SCD)

Sickle cell disease (SCD) is caused by a mutant β-globin gene and affects more than 100,000 individuals in the USA alone. Sickled RBCs and ischemic events cause tissue damage, altered splenic architecture, and inflammation. When children are infected with parvovirus B19, they can develop life-threatening aplastic crisis. Previous reports have described immune defects among patients with SCD, and their potential correlations with splenic dysfunction or inflammation. In a multi-center study involving St. Jude, NIH, Novartis, and GlaxoSmithKline, we examined (i) inflammatory cytokines/chemokines in patients with SCD, treated or untreated with hydroxyurea (HU); (ii) immune responses toward parvovirus B19 infections in children with SCD; and (iii) immune responses in a mouse model for SCD against a candidate Saccharomyces cerevisiae-derived parvovirus B19 VLP vaccine. Results showed that HU treatment reduced serum cytokines/chemokines in patients with SCD (e.g. TGFα, TNFα, and sVCAM-1). Both HU-treated and untreated children, regardless of their cytokine/chemokine profile, responded to parvovirus B19. Binding antibodies were apparent in the nasal cavity (a common point-of entry for the pathogen) and sera by day 7 post-infection, and virus-specific neutralizing antibodies were induced. In transgenic mice with SCD (expressing human α, βS, and γ globin genes), we observed normal antibody activities toward the VLP vaccine. Together, data show that parvovirus B19 -specific B cells withstand the aberrant SCD environment better than their previously-described Streptococcus pneumonia-specific B cell counterparts. Data encourage rapid development of the VLP vaccine to prevent aplastic crises in children with SCD.

The impact of bacterial superinfection during influenza infection of allergic hosts

Allergic asthma can be complicated by respiratory pathogens. However, asthmatics suffered less severe morbidity and mortality compared to non-asthmatics during the 2009 influenza A virus (IAV) pandemic. Using a novel mouse model, we determined that IAV infection during allergic airways inflammation protects the host from influenza. Pathogen-pathogen interactions between IAV and Streptococcus pneumoniae (Spn) can lead to fatal outcomes in a healthy host. We hypothesized that allergic hosts will have less morbidity and mortality associated with Spn superinfection after influenza. Infectious IAV was undetectable in the lungs at 72 h after Spn. Similar to animals infected with Spn alone, asthma+Spn mice cleared the bacteria completely by 72 h. Bacterial burden increased in the bronchoalveolar lavage fluid (BALF), lungs, and blood of mice in the IAV+Spn co-infection group. However, bacterial load in animals subjected to the fungal asthma model prior to viral and bacterial infections were significantly reduced in the BALF and absent in the lungs and blood. More leukocytes were found in the BALF of mice infected with IAV. The number of macrophages was similar between all groups, while those in the asthma+IAV, asthma+Spn, asthma+IAV+Spn groups had prominent amounts of eosinophils and CD4+ T cells (30% each) in the airways which was significantly higher than the asthma-only, IAV-only, Spn-only, and IAV+Spn groups. Neutrophils were most abundant in the IAV+Spn controls while the greatest number of CD8+ T cells was present in the IAV-only controls. The lung microbiome was significantly different in asthma+IAV+Spn. Remarkably, the asthma+IAV+Spn group did not have severe morbidity or mortality typically associated with IAV+Spn coinfection.

Vitamin A deficient mice are highly susceptible to Streptococcus pneumoniae and exhibit a poor response to vaccination with Prevnar-13

Streptococcus pneumoniae (pneumococcus) is frequently found in the human respiratory tract and can cause a wide range of diseases from mild otitis to fatal pneumonia or meningitis. It is estimated that pneumococcus kills 1.6 million people each year, approximately half of whom are children in developing nations. Given that vitamin A deficiency (VAD) occurs in both developed and developing countries, we sought to explore the relationship between VAD and pneumococcal disease. Previously, we have shown that mice with VAD fail to clear respiratory virus infections efficiently, resulting in a prolonged state of inflammation. Here we show that mice with VAD are more likely to develop a severe lung infection following intranasal infection with pneumococcus compared to vitamin A sufficient controls. We also found that VAD increases morbidity and mortality from secondary pneumococcal infections in influenza-infected mice. This increased sensitivity to pneumococcal infections led us to investigate the effectiveness of the human pneumococcal vaccine Prevnar-13 (PCV) in the context of VAD. Vaccinated mice with VAD mounted only minimal IgM and IgG antibody responses toward PCV compared to controls. Upon challenge with an invasive strain (TIGR4) of pneumococcus, vaccinated control animals were nearly 100% protected from disease with no detectable bacteremia at 24 hours post-infection, whereas nearly 1/3 of vaccinated VAD animals developed bacteremia within 24 hours and ultimately succumbed to the infection. Our results suggest that clinical analyses of children in both developed and developing countries should be conducted to ensure that PCV successfully protects against pneumococcal disease in individuals with VAD.

Parvovirus-mediated aplastic crisis and the virus-specific immune response in patients with sickle cell disease (VAC6P.948)

Parvovirus infection, which is typically subclinical in healthy individuals, can have catastrophic effects in patients suffering from sickle cell disease (SCD). Infection disrupts erythropoiesis, often resulting in aplastic crisis and other life-threatening complications in patients with SCD. Attempts to develop a safe and effective parvovirus vaccine have yet to be successful and may be improved by a better understanding of natural immune responses to parvovirus infections. St. Jude Children's Research Hospital houses one of the largest centers for pediatric SCD in the United States and is therefore uniquely positioned to monitor immune functions in patients with SCD. Here, we describe a retrospective analysis of patient records, examining parvovirus-specific antibody results from a semi-quantitative, commercially-available ELISA as a function of time relative to aplastic crisis. Results showed: (i) frequencies of seropositive immune responses in patients with SCD of various age groups were comparable to those of healthy controls, (ii) parvovirus-specific immune responses were rapidly induced in patients following aplastic crisis, and (iii) responses were generally sustained for years after the aplastic crisis event. Ongoing studies include further dissection of adaptive and innate immune responses toward parvovirus infections in this patient population to help define correlates of protection against parvovirus disease.

Reverse endoventricular artificial obturator in tricuspid valve position. Experimental feasibility research study

The concept of vena contracta space reduction in tricuspid valve position was tested in an animal model. Feasibility of specific artificial obturator body (REMOT) fixed to the right ventricular apex and interacting with tricuspid valve leaflets was evaluated in three different animal studies. Catheter-based technique was used in three series of experiment in 7 sheep. First acute study was designed for evaluation if the screwing mode of guide wire anchoring to the right ventricular apex is feasible for the whole REMOT body fixing. Longer study was aimed to evaluate stability of the REMOT body in desired position when fixing the screwing wire on its both ends (to the right ventricular apex and to the skin in the neck area). X-ray methods and various morphological methods were used. The third acute study was intended to the REMOT body deployment without any fixing wire. In all of 7 sheep the REMOT was successfully inserted into the right heart cavities and then fixed to the right ventricular apex area. When the REMOT was left in situ more than 6 months it was stable, induced adhesion to the tricuspid valve leaflet and was associated with a specific cell invasion. Releasing of the REMOT from the guiding tools was also successfully verified. Deployment of the obturator body in the aim to reduce the tricuspid valve orifice is feasible and well tolerated in the short and longer term animal model. Specific cell colonization including neovascularization of the obturator body was observed.

A microdomain for protein secretion in Gram-positive bacteria

Gram-positive bacteria face unique challenges in generating biologically active conformations for their exported proteins because they lack a dedicated compartment for folding secreted polypeptides. We have discovered that protein secretion by way of the general secretory (Sec) pathway in the important human pathogen Streptococcus pyogenes proceeds through a single microdomain. Unlike other mechanisms for asymmetry involving the Sec pathway, proteins destined for secretion are targeted to a single locus distal to either cell pole that has specialized to contain the Sec translocons. This subcellular organization may represent a paradigm for secretion common to other Gram-positive pathogens with profound implications for pathogenesis.

Intravascular US-guided direct intrahepatic portacaval shunt with a PTFE-covered stent-graft: feasibility study in swine and initial clinical results

PURPOSE

To determine the feasibility of the creation of a direct intrahepatic inferior vena cava (IVC)-to-portal-vein shunt with puncture guided by a transfemorally placed intravascular ultrasound (IVUS) probe and use of a polytetrafluoroethylene (PTFE)-covered stent-graft.

MATERIALS AND METHODS

In five swine, transjugular access was used to perform a direct puncture from the IVC to the portal vein with use of a modified Rosch-Uchida Portal Access set directed with real-time IVUS (9 MHz) introduced from a transfemoral venous approach. The direct intrahepatic portocaval shunt (DIPS) was then created with single or overlapping PTFE-covered Palmaz stents placed through a 10-F sheath and dilated to a diameter of 8 mm. Follow-up was performed with transhepatic portography at 2, 4, and 8 weeks. Animals were killed when shunts occluded or at the termination of the study at 8 weeks. Gross and microscopic histologic study was performed on sacrificed animals. A similar technique was used to create DIPS in five patients with intractable ascites, with follow-up by US and venography.

RESULTS

All experimental DIPS created in swine were created without complications. Portal vein punctures were achieved in four of five swine on the first or second pass of the needle. Follow-up transhepatic portography at 2 weeks demonstrated occlusion of two shunts, both explained by technical reasons at sacrifice. At 4 and 8 weeks, the remaining three shunts were patent on portography. Histology showed a thin neointimal lining with no significant tissue ingrowth or hyperplasia. Clinically, in five patients, successful puncture of the portal vein from the IVC was achieved in one to three passes. Creation of DIPS led to a reduction of mean portosystemic gradient from 18-29 mm Hg (mean, 24 mm Hg) to 9-10 mm Hg (mean, 9 mm Hg). One patient died of liver failure 2 days after creation of DIPS. The other four patients were doing well 2-15 months (mean, 8 months) after the procedure, with patency confirmed by US and venography.

CONCLUSION

Creation of DIPS is technically feasible, and the direct IVC-to-portal-vein puncture can be done accurately with real-time IVUS guidance. Further studies and longer follow-up are necessary to determine if the short length of the PTFE-covered stent-graft and avoidance of the hepatic vein will increase the long-term patency compared to standard transjugular intrahepatic portosystemic shunt creation.

Transjugular intrahepatic portosystemic shunt with silicone-covered Wallstents: results in a swine model

PURPOSE

To evaluate the use of impermeable silicone-covered Wallstents for transjugular intrahepatic portosystemic shunt creation.

MATERIALS AND METHODS

A transjugular intrahepatic portosystemic shunt was created in 14 young swine (weight, 20-32 kg) by using impermeable silicone-covered Wallstents. In eight animals, the silicone covering extended from the portal vein to the inferior vena cava. In two swine, the silicone covering ended short of the inferior vena cava, in two it ended short of the portal vein wall, and in two it ended short at each end. Follow-up transhepatic portal venography was performed weekly for 6 weeks or until the shunt was occluded. Animals were then sacrificed for gross and histologic evaluation.

RESULTS

Only two of 14 shunts were patent after 3 weeks; both were stenosed with luminal narrowing of more than 50% in the middle of the shunt. By 6 weeks, all shunts were occluded. At histologic evaluation, a marked foreign-body reaction with superimposed thrombosis was demonstrated.

CONCLUSION

In comparison with uncovered Wallstents, impermeable silicone-covered Wallstents are associated with decreased patency at transjugular intrahepatic portosystemic shunt creation. This is likely due to increased thrombogenicity and a foreign-body reaction.

Angiographic evaluation and management of nonvariceal upper gastrointestinal bleeding

Endoscopy is the primary diagnostic and therapeutic tool used in the evaluation and treatment of patients with upper gastrointestinal bleeding. When endoscopy is unsuccessful in identifying or controlling GI hemorrhage, however, arteriography is useful in both the evaluation and treatment of upper GI hemorrhage.

Outcome of 100 patients after transjugular intrahepatic portosystemic shunt for variceal hemorrhage

OBJECTIVES

One hundred consecutive patients with recurrent or refractory acute variceal hemorrhage treated with a transjugular intrahepatic portosystemic shunt (TIPS) from June 1990 to June 1993 at Oregon Health Sciences University or the Portland Veterans Affairs Medical Center were evaluated to assess shunt patency and clinical outcome, including complications of TIPS, rebleeding, and survival.

METHODS

Success of shunt placement, reduction in portal pressure, complications, survival, recurrent hemorrhage, severity of ascites, hepatic encephalopathy before and after TIPS, and shunt patency were assessed in each patient.

RESULTS

The mean follow-up period was 17.7 months (range, 0.1-56.7 months). TIPS was successfully completed in all patients, with a mean reduction in portosystemic gradient from 24 to 11 mm Hg. Major complications occurred in 11 patients, including one death. Survival after TIPS was 85% at 30 days, 71% at 1 yr, and 56% at 2 yr. Variceal bleeding stopped within 24 hours after TIPS in all eight patients with active hemorrhage. Recurrent variceal hemorrhage occurred in 18 patients at a mean of 4.3 months (range, 1-713 days) after TIPS. The cumulative rate of recurrent variceal bleeding was 20% at 1 yr and 25% at 2 yr after TIPS. Recurrent variceal bleeding was associated with shunt stenosis or occlusion in all patients with endoscopically documented variceal hemorrhage, which was successfully managed by reopening obstructed shunts and performing variceal embolization. The prevalence of ascites was significantly reduced among surviving patients evaluated 3 months after TIPS (67 vs 25%, p < 0.005). Three months after TIPS, the incidence of new or worsening hepatic encephalopathy was 20%, but encephalopathy improved in an equal proportion of patients. Seventy-three of 77 (95%) shunts examined for patency were open at the last follow-up examination. However, most shunts required intervention to maintain patency, and only 48% (37 of 77) were primarily patent at a mean of 168 days (range, 2-538 days) of follow-up. Shunt stenosis or occlusion, as determined by venography, became increasingly frequent with longer follow-up (52% at 3-9 months and 70% at 9-15 months).

CONCLUSIONS

TIPS is effective in lowering elevated portal pressures in patients with refractory variceal hemorrhage, has acceptable postprocedure complication and mortality rates, ameliorates ascites, and in, a minority of patients, worsens encephalopathy. Shunt stenosis occurs in the majority of patients but can be effectively treated by interventional techniques to maintain patency. The incidence of recurrent variceal hemorrhage is low and is associated with shunt stenosis or occlusion.

Prior radiation and chemotherapy increase the risk of life-threatening complications after insertion of metallic stents for esophagogastric malignancy

BACKGROUND

Self-expanding metallic stents (SEMS) are effective in relieving the symptoms of obstructing esophagogastric malignancy. While complications with SEMS have been described, factors influencing such occurrence have not been defined.

METHODS

Self-expanding Gianturco-Rosch Z-stents were placed successfully in 59 patients with obstructing esophagogastric malignancies.

RESULTS

Early procedure-related complications occurred in 6 patients (10%) and were usually minor. Twenty-three late complications occurred in 22 patients (37.5%). Life-threatening complications occurred in 9 patients (15%), including gastrointestinal bleeding (7), perforation (1), and tracheoesophageal fistula (1) and contributed to all five deaths. Eight of 22 patients with prior radiation and/or chemotherapy (36.4%) had life-threatening complications compared to 1 of 37 (2.5%) without prior therapy (p = 0.001). Stent-related mortality occurred in 5 of 22 (23%) patients with prior therapy compared to none of the 37 without prior therapy (p = 0.005). Multivariate analysis confirmed the association between prior radiation and/or chemotherapy and life-threatening complications (p = 0.012; odds ratio, 32.63) and also an association with female gender (p = 0.032; odds ratio, 13.9). There was no association with tumor location or length, histologic type, age, prestent dysphagia grade, or previous surgical resection.

CONCLUSION

Patients with prior radiation and/or chemotherapy have an increased risk of severe complications following placement of SEMS.

Effects of hepatic artery embolization with Lipiodol and gelatin sponge particles on normal swine liver

In order to evaluate the effects of hepatic artery embolization (HAE) with Lipiodol (Lp) and gelatin sponge particles (GSP) on swine liver tissue, we embolized the hepatic arteries of 3 pigs with GSP, 9 with Lp, and 9 with Lp + GSP. None of the pigs embolized with GSP died spontaneously during the 4-week experimental period. One pig embolized with 1 ml/kg Lp and three pigs with 2 ml/kg Lp died within 2 h. Two pigs embolized with 0.5 ml/kg Lp + GSP died the following day. The portal vein pressure (PVP) and wedge hepatic vein pressure (WHVP) values before HAE, immediately after, 1 h after, and 4 weeks after HAE showed no remarkable change in the GSP group. Remarkable and temporary elevation was observed in the more than 0.2 ml/kg Lp group. Remarkable and continuous elevation was observed in the 0.2 ml/kg Lp + GSP and 0.5 ml/kg Lp + GSP groups. Gross and histological studies demonstrated no liver damage in the GSP and Lp group. Liver infarction, circular coagulation necrosis with pseudocapsule, and liver atrophy were found in the Lp + GSP group 4 weeks after HAE. The incidence of infarction, circular coagulation necrosis, and liver atrophy in the livers embolized with 0.2 ml/kg Lp + GSP and 0.5 ml/kg Lp + GSP were 67%, 100%, and 75%, respectively. In conclusion, when the hepatic artery is embolized with Lp + GSP, the volume of Lp should be limited to less than 0.1 ml/kg.

Distribution and effect of iodized poppyseed oil in the liver after hepatic artery embolization: experimental study in several animal species

To define the intrahepatic distribution of iodized poppyseed oil and its effect on the liver, hepatic artery embolization (HAE) was performed in five mice, 12 rats, four rabbits, and 21 pigs with the iodized oil alone or in combination with gelatin sponge powder (GSPow) in three rats or gelatin sponge particles (GSPs) in nine pigs. All mice, rats, and rabbits underwent radiography of the upper abdomen and in vivo microscopy of the hepatic periphery during and immediately after injection and 1, 4, and 24 hours later. All pigs underwent angiography before and after HAE as well as measurement of portal venous pressure before HAE and 15, 30, 45, and 60 minutes and 4 weeks after HAE. Follow-up radiographs were obtained in 18 pigs. HAE performed with the iodized oil only was well tolerated by the liver, even when high doses were used, likely because of continuous flushing of the sinusoids by high blood flow from peripheral arterioles. When HAE was performed with the iodized oil and GSPow, this blood flow ceased and necrosis developed. The degree of necrosis after HAE with the iodized oil in combination with GSPs was directly associated with the dose of iodized oil. HAE performed with GSPs only did not cause damage.

Venous stenoses in patients who undergo hemodialysis: treatment with self-expandable endovascular stents

During a 32-month period, 25 modified self-expandable endovascular stents were placed in 20 hemodialysis access sites to treat 21 stenoses and four occlusions in 19 patients. All stenoses were initially dilated with a high-pressure balloon. The initial success rate was 90% (18 of 20 access sites). The stents were patent from 0 to 960 days (mean duration of follow-up, 309 days). At 2 years follow-up, the patency rates were as follows: primary, 25%; secondary, 34%; and tertiary, 42%. The morbidity rate associated with this procedure was 15% (three of 20 sites); the mortality rate, 5% (one of 19 patients). All five complications (graft or native-vein thrombosis [n = 2], nerve deficits [n = 2], and death secondary to sepsis [n = 1]) occurred in three patients early in the study, before the use of prophylactic antibiotics and refinements in technique. The best results occurred in patients in whom the stenosis or occlusion affected a large vein that had no acute angle and was away from venous confluences such as the femoral and iliac regions.

Recovery of function in a solitary kidney after intra-arterial thrombolytic therapy

Renal artery thromboembolism is a rare event that most often occurs in patients with cardiac dysrhythmias. Surgical thromboembolectomy is risky and medical therapy with intra-arterial thrombolytic agents has become increasingly popular. Although successful clot dissolution has been well documented, renal function often is not recovered. We describe a patient with anuria from thromboembolism to a solitary kidney, treated with low dose intra-arterial streptokinase infusion. There were no adverse effects from therapy and renal function returned to a point where dialysis was no longer required. A review of the literature is included with special attention to various protocols for infusion. Early diagnosis and prompt initiation of therapy may result in clinically significant recovery of renal function.

Small vessel leg angiography for distal vessel bypass grafts

To improve visualization of the small vessels for distal bypass grafting, arteriograms of the lower extremity were obtained in 187 patients by use of active warming of the extremities, selective distal positioning of the catheter for contrast agent injections, and intraarterial administration of tolazoline. With these techniques, satisfactory visualization was obtained for planning of operation, and in only one patient was an intraoperative arteriogram necessary before bypass grafts were placed.

Diagnosis of cornual obstruction by transcervical fallopian tube cannulation

Interstitial fallopian tube obstruction (IFTO) occurs in 15% of hysterosalpingograms (HSG) performed for infertility. Conventional HSG or laparoscopy may not differentiate cornual spasm or other temporary cause from true obstruction. We used transcervical cannulation of the proximal oviduct with a 3-F Teflon catheter and flexible guidewire 0.018 inch (0.043 cm) in diameter under hysteroscopic or fluoroscopic guidance to evaluate IFTO in 28 patients. Fluoroscopic catheterization techniques with selective salpingography demonstrated patency in 84% of obstructed tubes. Hysteroscopic cannulation with direct visualization by laparoscopy or laparotomy was successful in 92%. In one patient, perforation of the isthmus occurred without sequelae. Transcervical coaxial cannulation of the proximal oviduct is an effective method for evaluating cornual obstruction.

Urokinase in gastrointestinal tract bleeding

Selective urokinase infusion into the superior mesenteric artery allowed the accurate determination of the site of small bowel bleeding in a patient with recurrent lower gastrointestinal bleeding who bled despite resective surgery and who had negative findings on four angiograms. Fibrinolytic agents are useful in rare cases in which the need for successful and accurate diagnosis outweighs the risks of reactivating the bleeding.

Nonbronchial systemic collateral arteries: significance in percutaneous embolotherapy for hemoptysis

Twenty patients with massive or recurrent hemoptysis underwent percutaneous transcatheter embolotherapy between 1979 and 1986 for the following diseases: cavitary aspergillosis (n = 4); cystic fibrosis (n = 4); tuberculosis (n = 3); bronchogenic carcinoma (n = 3); bronchiectasis (n = 3); small cell lung carcinoma 6 years after irradiation (n = 1); congenital heart disease, after Glenn and Blalock anastomoses (n = 1); and unknown interstitial disease (n = 1). Bronchial arteries were embolized in all but one patient. In nine patients (45%) nonbronchial systemic collateral arteries contributed significantly to areas of pathologic pulmonary tissue and frequently were the major arterial supply. These nonbronchial systemic collaterals included branches of the subclavian and axillary arteries (n = 7), intercostal arteries (n = 5), and phrenic arteries (n = 3) and accounted for 59.5% of the total number of arteries embolized. Recognition and occlusion of nonbronchial systemic collaterals providing blood to hypervascular pulmonary lesions is essential for successful percutaneous embolotherapy of hemoptysis.

Hepatogenic pulmonary angiodysplasia treated with coil-spring embolization

Coil-spring embolization is a procedure for treatment of pulmonary arteriovenous malformations. Herein is described a patient with hepatogenic pulmonary angiodysplasia ("pulmonary spiders") managed with this technique.

Selective therapeutic embolization of renal cell carcinoma in solitary kidneys

We report 3 cases of renal cell carcinoma in a solitary kidney treated by selective tumor embolization. Embolization resulted in occlusion of the majority of the vascular supply of the tumor, with preservation of normal renal parenchyma and sufficient renal function. Selective tumor embolization is a good therapeutic alternative in patients in whom partial nephrectomy cannot be performed. Owing to the limited availability of bucrylate, absolute ethanol is recommended as the preferred embolic agent.

Percutaneous renal ablation in patients with end-stage renal disease: alternative to surgical nephrectomy

Percutaneous transcatheter ablation was performed on 18 kidneys in ten patients with end-stage renal disease (ESRD), who were either on hemodialysis or had undergone renal transplantation, for the following indications: nephrotic syndrome with massive protein loss (seven patients, 13 kidneys), poorly controlled posttransplantation hypertension in the absence of transplant renal artery stenosis (two patients, three kidneys), and diabetic nephropathy with persistent urine leak from ureterocutaneous fistulas following pelvic irradiation (one patient, two kidneys). Desired clinical results were achieved in all cases. Percutaneous renal ablation is an effective alternative to surgery in patients with ESRD who require nephrectomy.

Arterial embolization for massive upper gastrointestinal tract bleeding in poor surgical candidates

Therapeutic vascular occlusion was used in 32 patients to control massive upper gastrointestinal tract bleeding. All patients were poor surgical candidates and received an average of 12 U of red cells before embolization. Control of bleeding (for greater than 24 h) was attained in 23 of 32 patients (72%). Six of these 23 patients (26%) subsequently died within a 6-mo follow-up period, 5 due to underlying diseases, and only 1 due to rebleeding. Nine patients were not controlled initially with embolization, although 6 had marked reduction in bleeding. Eight of these 9 patients died (89%), 6 from hemorrhage or emergent gastric surgery, and 2 from underlying diseases. All patients with Mallory-Weiss tears (5) and with hemobilia (3) were successfully treated with embolization. Serious complications included gastric infarction in 2 patients with prior compromise of gastric arterial supply. Embolization offers an efficacious alternative to emergent surgery for control of massive upper gastrointestinal arterial hemorrhage in the poor risk surgical candidate.

Natural history of asymptomatic coronary arteriographic lesions in diabetic patients with end-stage renal disease

Arteriosclerotic heart disease is a major cause of death in insulin-requiring juvenile diabetic patients treated for end-stage renal disease. Eleven consecutive diabetic patients without clinical evidence of coronary artery disease underwent complete cardiac evaluations, including coronary arteriography, as part of transplant recipient work-ups. Seven were women and four were men; their mean age was 32 (21 to 50 years). Angiographically, every patient had multifocal atherosclerotic coronary disease. Four of seven patients tested had positive-stress electrocardiograms. In this group of patients followed for a mean of 19.8 months, eight died. Of these deaths, six were due to coronary heart disease and another due to a stroke. In two patients who became clinically symptomatic, serial angiograms revealed progressive disease of the coronary circulation; in one case, despite normal renal allograft function and serum lipid levels. The mode of end-stage renal disease treatment, serum lipids or blood pressure control could not be linked to mortality. It is concluded that arteriosclerotic heart disease is common in diabetic patients with end-stage renal disease even when angina is absent. The natural history in this high risk population is an important consideration in the selection of patients for end-stage renal disease treatment.

Percutaneous transhepatic obliteration of gastroesophageal varices: some technical aspects

Two cases of bleeding from gastroesophageal varices treated by variceal obliteration illustrate multiple routes of variceal supply, and alert embolizing angiographers to the presence of spontaneous portosystemic shunts which should be kept open. In one case, variceal obliteration required embolization of the left gastric vein and a transhepatic collateral originating from the left hepatic portal branch and contributing substantially to variceal filling. A second patient with a relatively large spontaneous splenorenal shunt had recurrent variceal bleeding two months after a successful embolization of the coronary vein and a short gastric vein. A repeat study revealed the recurrent varices were supplied by enlarged right gastric and gastroepiploic veins. Superior mesenteric venography was necessary for their visualization.

The role of arteriography in abdominal aortic aneurysm

The results of arteriography in the management of 100 consecutive patients with abdominal aortic aneurysms are presented. Arteriographic information had substantial influence upon management decisions and performance of surgery in 75 per cent of cases. We found the preoperative knowledge of the precise vascular pathology or anatomic variants not only permitted a more rational recommendation for or against surgery but aided in the selection of the most suitable surgical procedure.

Cromolyn sodium nasal solution in the prophylactic treatment of pollen-induced seasonal allergic rhinitis

A large-scale multicenter investigation was undertaken in 3 cities with comparable pollen seasons and atmospheric pollen concentrations in order to obtain more definite information about the safety and efficacy of cromolyn sodium in the treatment of pollen-induced seasonal rhinitis. The 9-wk double-blind study was conducted in 104 patiets in Pittsburgh, Pa., Cleveland, Ohio, and Louisville, Ky., during the 1975 ragweed season. It indicated that a nebulized 4% aqueous solution of cromolyn sodium is effective in reducing sneezing, rhinorrhea, nasal congestion, and ocular irritation in ragweed hay fever patients. The efficacy of the drug was notable despite the fact that patients used an average of 52 mg instead of the recommended 62.4 mg daily. Cromolyn sodium did not appear to have a significant effect on transseasonal antiragweed IgE (IgEAR) levels. Patients acceptance of the cromolyn nasal solution was good, and there were no significant adverse reactions. The side effects, which were distributed equally between the drug and placebo groups, were mild and of limited duration.

Acute coronary insufficiency with normal coronary arteriograms

Two patients presenting with apparent symptomatic and electrocardiographic evidence of acute coronary insufficiency and found to have normal coronary arteriograms are documented. The patients remain symptom free at follow-up 9 and 14 months later although one requires 160 mg propranolol daily. The electrocardiographic, myocardial metabolic and haemodynamic data in 413 patients with angina and normal coronary arteriograms are reviewed and the suggested aetiologies documented. Follow-up of patients in these series indicates a good prognosis for symptom-free survival.

Angiography in the diagnosis and therapy of frostbite

Five patients with frostbite injury were studied by selective angiography and treated by selective intra-arterial application of reserpine with follow-up angiography two days later. Control angiograms showed various degrees of vascular spasm as well as organic stenosis and occlusion. Intra-arterial reserpine produced dramatic subsiding of vasospasm, as evidenced by angiography and relief of clinical symptoms. Complete healing without tissue loss occurred in 4 patients. Amputation was necessary in one case, due at least in part to pre-existing peripheral atherosclerotic disease. Selective angiography was found to contribute significantly to both the diagnosis and therapy of frostbite injury.

Retrograde pancreatic venography. An experimental study

To explore the feasibility of retrograde pancreatic venography, transhepatic portal catherization via jugular and hepatic veins was performed in 10 dogs. Coaxially introduced catheters were then used to enter individual pancreatic veins for retrograde venography. Appropriate injection technique led to detailed visualization of the pancreatic venous system without anatomically evident injury to the pancreas. The (readily avoidable) injection of contrast agent through catheters wedged into pancreatic veins caused parenchymal extravasation and hemorrhagic pancreatitis. The detection of pancreatic cancer in patients not approachable by arteriography and the intensified search for small islet cell tumors are possible indications for pancreatic venography when the safety of this method is further demonstrated.