Moraxella ovis and Moraxella bovoculi lipooligosaccharide biosynthesis genes, and structural characterisation of oligosaccharide from M. ovis 354T

Moraxella ovis is a Gram-negative bacterium isolated from sheep conjunctivitis cases and is a rare isolate of infectious bovine keratoconjunctivitis (IBK). This species is closely related to M. bovoculi, another species which can also be isolated from IBK, or cattle upper respiratory tract (URT). Prior to molecular identification techniques, M. bovoculi was frequently misclassified as M. ovis. We previously described the structure of two oligosaccharides (lipooligosaccharide-derived, minor and major glycoforms) from M. bovoculi 237T (type strain, also ATCC BAA-1259T). Here, we have identified the genetic loci for lipooligosaccharide synthesis in M. ovis 354T (NCTC11227) and compared it with M. bovoculi 237T. We identified genes encoding the known glycosyltransferases Lgt6 and Lgt3 in M.ovis. These genes are conserved in Moraxella spp., including M bovoculi. We identified three further putative OS biosynthesis genes that are restricted to M. ovis and M. bovoculi. These encode enzymes predicted to function as GDP-mannose synthases, namely a mannosyltransferase and a glycosyltransferase. Adding insight into the genetic relatedness of M.ovis and M. bovoculi, the M. ovis genes have higher similarity to those in M. bovoculi genotype 2 (nasopharyngeal isolates from asymptomatic cattle), than to M. bovoculi genotype 1 (isolates from eyes of IBK-affected cattle). Sequence analysis confirmed that the predicted mannosyltransferase in M. bovoculi 237T is interrupted by a C>T polymorphism. This mutation is not present in other M. bovoculi strains sequenced to date. We isolated and characterised LOS-derived oligosaccharide from M. ovis 354T. GLC-MS and NMR spectroscopy data revealed a heptasaccharide structure with three β-D-Glcp residues attached as branches to the central 3,4,6-α-D-Glcp, with subsequent attachment to Kdo. This inner core arrangement is consistent with the action of Lgt6 and Lgt3 glycosyltransferases. Two α-D-Manp residues are linearly attached to the 4-linked β-D-Glcp, consistent with the presence of the two identified glycosyltransferases. This oligosaccharide structure is consistent with the previously reported minor glycoform isolated from M. bovoculi 237T.

Diverse Sensory Repertoire of Paralogous Chemoreceptors Tlp2, Tlp3, and Tlp4 in Campylobacter jejuni

Campylobacter jejuni responds to extracellular stimuli via transducer-like chemoreceptors (Tlps). Here, we describe receptor-ligand interactions of a unique paralogue family of dCache_1 (double Calcium channels and chemotaxis) chemoreceptors: Tlp2, Tlp3, and Tlp4. Phylogenetic analysis revealed that Tlp2, Tlp3, and Tlp4 receptors may have arisen through domain duplications, followed by a divergent evolutionary drift, with Tlp3 emerging more recently, and unexpectedly, responded to glycans, as well as multiple organic and amino acids with overlapping specificities. All three Tlps interacted with five monosaccharides and complex glycans, including Lewis's antigens, P antigens, and fucosyl GM1 ganglioside, indicating a potential role in host-pathogen interactions. Analysis of chemotactic motility of single, double, and triple mutants indicated that these chemoreceptors are likely to work together to balance responses to attractants and repellents to modulate chemotaxis in C. jejuni. Molecular docking experiments, in combination with saturation transfer difference nuclear magnetic resonance spectroscopy and competition surface plasmon resonance analysis, illustrated that the ligand-binding domain of Tlp3 possess one major binding pocket with two overlapping, but distinct binding sites able to interact with multiple ligands. A diverse sensory repertoire could provide C. jejuni with the ability to modulate responses to attractant and repellent signals and allow for adaptation in host-pathogen interactions. IMPORTANCE Campylobacter jejuni responds to extracellular stimuli via transducer-like chemoreceptors (Tlps). This remarkable sensory perception mechanism allows bacteria to sense environmental changes and avoid unfavorable conditions or to maneuver toward nutrient sources and host cells. Here, we describe receptor-ligand interactions of a unique paralogue family of chemoreceptors, Tlp2, Tlp3, and Tlp4, that may have arisen through domain duplications, followed by a divergent evolutionary drift, with Tlp3 emerging more recently. Unlike previous reports of ligands interacting with sensory proteins, Tlp2, Tlp3, and Tlp4 responded to many types of chemical compounds, including simple and complex sugars such as those present on human blood group antigens and gangliosides, indicating a potential role in host-pathogen interactions. Diverse sensory repertoire could provide C. jejuni with the ability to modulate responses to attractant and repellent signals and allow for adaptation in host-pathogen interactions.

Structural characterisation of the oligosaccharide from Moraxella bovoculi type strain 237 (ATCC BAA-1259) lipooligosaccharide

The Gram-negative bacterium Moraxella bovoculi is associated with infectious bovine keratoconjunctivitis (IBK), colloquially known as 'pink-eye'. IBK is an extremely contagious ocular disease of cattle. We report here the structure of the oligosaccharide derived from the lipooligosaccharide from M. bovoculi type strain 237 (also known as ATCC BAA-1259T). GLC-MS and correlation NMR analysis of the oligosaccharide revealed 5 sugar residues, with a notable central branched 3,4,6-α-D-Glcp. An additional α-D-Manp was present ~30% on the sub-terminal α-D-Manp of the 4-linked branch. This oligosaccharide structure was consistent with other members of the Moraxellaceae where no heptose was present and 5-linked Kdo was directly attached to the central 3,4,6-α-D-Glcp.

The Campylobacter jejuni chemoreceptor Tlp10 has a bimodal ligand-binding domain and specificity for multiple classes of chemoeffectors

Campylobacter jejuni is a bacterial pathogen that is a common cause of enteritis in humans. We identified a previously uncharacterized type of sensory domain in the periplasmic region of the C. jejuni chemoreceptor Tlp10, termed the DAHL domain, that is predicted to have a bimodular helical architecture. Through two independent ligand-binding sites in this domain, Tlp10 responded to molecular aspartate, isoleucine, fumarate, malate, fucose, and mannose as attractants and to arginine, galactose, and thiamine as repellents. Tlp10 also recognized glycan ligands when present as terminal and intermediate residues of complex structures, such as the fucosylated human ganglioside GM1 and Lewis^a antigen. A tlp10 mutant strain lacking the ligand-binding sites was attenuated in its ability to colonize avian caeca and to adhere to cultured human intestinal cells, indicating the potential involvement of the DAHL domain in host colonization and disease. The Tlp10 intracellular signaling domain interacted with the scaffolding proteins CheV and CheW, which couple chemoreceptors to intracellular signaling machinery, and with the signaling domains of other chemoreceptors, suggesting a key role for Tlp10 in signal transduction and incorporation into sensory arrays. We identified the DAHL domain in other bacterial signal transduction proteins, including the essential virulence induction protein VirA from the plant pathogen Agrobacterium tumefaciens Together, these results suggest a potential link between Tlp10 and C. jejuni virulence.

Characterization of Ligand-Receptor Interactions: Chemotaxis, Biofilm, Cell Culture Assays, and Animal Model Methodologies

Chemotactic motility is an essential virulence factor for the pathogenesis of Campylobacter spp. infection. In Chapter 6 , we described technologies that enable initial screening and identification of ligands able to interact with chemoreceptor sensory domains. These include amino acid and glycan arrays, NMR, and SPR that are utilized to identify potential ligands interacting with Campylobacter jejuni. Here we describe techniques that enable the characterization and evaluation of ligand-receptor binding in chemotaxis through the assessment of motility and directed chemotactic motility as well as the associated phenotypes-autoagglutination behavior, biofilm formation, ability to adhere and invade cultured mammalian cells, and colonization ability in avian hosts.

A direct-sensing galactose chemoreceptor recently evolved in invasive strains of Campylobacter jejuni

A rare chemotaxis receptor, Tlp11, has been previously identified in invasive strains of Campylobacter jejuni, the most prevalent cause of bacterial gastroenteritis worldwide. Here we use glycan and small-molecule arrays, as well as surface plasmon resonance, to show that Tlp11 specifically interacts with galactose. Tlp11 is required for the chemotactic response of C. jejuni to galactose, as shown using wild type, allelic inactivation and addition mutants. The inactivated mutant displays reduced virulence in vivo, in a model of chicken colonization. The Tlp11 sensory domain represents the first known sugar-binding dCache_1 domain, which is the most abundant family of extracellular sensors in bacteria. The Tlp11 signalling domain interacts with the chemotaxis scaffolding proteins CheV and CheW, and comparative genomic analysis indicates a likely recent evolutionary origin for Tlp11. We propose to rename Tlp11 as CcrG, Campylobacter ChemoReceptor for Galactose.

Characterisation of a multi-ligand binding chemoreceptor CcmL (Tlp3) of Campylobacter jejuni

Campylobacter jejuni is the leading cause of human gastroenteritis worldwide with over 500 million cases annually. Chemotaxis and motility have been identified as important virulence factors associated with C. jejuni colonisation. Group A transducer-like proteins (Tlps) are responsible for sensing the external environment for bacterial movement to or away from a chemical gradient or stimulus. In this study, we have demonstrated Cj1564 (Tlp3) to be a multi-ligand binding chemoreceptor and report direct evidence supporting the involvement of Cj1564 (Tlp3) in the chemotaxis signalling pathway via small molecule arrays, surface plasmon and nuclear magnetic resonance (SPR and NMR) as well as chemotaxis assays of wild type and isogenic mutant strains. A modified nutrient depleted chemotaxis assay was further used to determine positive or negative chemotaxis with specific ligands. Here we demonstrate the ability of Cj1564 to interact with the chemoattractants isoleucine, purine, malic acid and fumaric acid and chemorepellents lysine, glucosamine, succinic acid, arginine and thiamine. An isogenic mutant of cj1564 was shown to have altered phenotypic characteristics of C. jejuni, including loss of curvature in bacterial cell shape, reduced chemotactic motility and an increase in both autoagglutination and biofilm formation. We demonstrate Cj1564 to have a role in invasion as in in vitro assays the tlp3 isogenic mutant has a reduced ability to adhere and invade a cultured epithelial cell line; interestingly however, colonisation ability of avian caeca appears to be unaltered. Additionally, protein-protein interaction studies revealed signal transduction initiation through the scaffolding proteins CheV and CheW in the chemotaxis sensory pathway. This is the first report characterising Cj1564 as a multi-ligand receptor for C. jejuni, we therefore, propose to name this receptor CcmL, Campylobacterchemoreceptor for multiple ligands. In conclusion, this study identifies a novel multifunctional role for the C. jejuni CcmL chemoreceptor and illustrates its involvement in the chemotaxis pathway and subsequent survival of this organism in the host.

Bacterial chemotaxis is an important part in initiation of colonisation and subsequent pathogenicity. In this study, we report direct evidence supporting the involvement of C. jejuni transducer-like protein Cj1564 (Tlp3) in the chemotaxis signalling pathway via small molecule arrays, surface plasmon and nuclear magnetic resonance (SPR and NMR) as well as chemotaxis assays of wild type and isogenic mutants. We further demonstrate its ability to interact with chemoattractants isoleucine, purine, malic acid and fumaric acid and chemorepellents lysine, glucosamine, succinic acid, arginine and thiamine. This is the first report identifying Cj1564 as a multi-ligand receptor for Campylobacter jejuni and its signal transduction initiation through the CheV and CheW proteins. Finally, our characterisation of C. jejuni Cj1564 provides additional basis for elucidating the roles of other group A chemoreceptors and their importance in the chemotaxis signalling pathway.

Porcine brachial artery tortuosity for in vivo evaluation of neuroendovascular devices

We report a novel model of arterial tortuosity in the porcine brachial artery for testing of endovascular devices in the flexed forelimb position. This provides an ideal vascular territory for an in vivo assessment of guidewires, microcatheters, and endovascular implants because it closely mimics the challenging curvature at the carotid siphon.

The effect of intracranial stent implantation on the curvature of the cerebrovasculature

BACKGROUND AND PURPOSE

Recently, the use of stents to assist in the coiling and repair of wide-neck aneurysms has been shown to be highly effective; however, the effect of these stents on the RC of the parent vessel has not been quantified. The purpose of this study was to quantify the effect of intracranial stenting on the RC of the implanted artery using 3D datasets.

MATERIALS AND METHODS

Twenty-four patients receiving FDA-approved neurovascular stents to support coil embolization of brain aneurysms were chosen for this study. The stents were located in the ICA, ACA, or MCA. We analyzed C-arm rotational angiography and contrast-enhanced cone beam CT datasets before and after stent implantation, respectively, to ascertain changes in vessel curvature. The images were reconstructed, and the vessel centerline was extracted. From the centerline, the RC was calculated.

RESULTS

The average implanted stent length was 25.4 ± 5.8 mm, with a pre-implantation RC of 7.1 ± 2.1 mm and a postimplantation RC of 10.7 ± 3.5 mm. This resulted in a 3.6 ± 2.7 mm change in the RC due to implantation (P < .0001), more than a 50% increase from the pre-implantation value. There was no difference in the change of RC for the different locations studied. The change in RC was not impacted by the extent of coil packing within the aneurysm.

CONCLUSIONS

The implantation of neurovascular stents can be shown to have a large impact on the RC of the vessel. This will lead to a change in the local hemodynamics and flow pattern within the aneurysm.

Variation of chemosensory receptor content of Campylobacter jejuni strains and modulation of receptor gene expression under different in vivo and in vitro growth conditions

Background

Chemotaxis is crucial for the colonisation/infection of hosts with Campylobacter jejuni. Central to chemotaxis are the group A chemotaxis genes that are responsible for sensing the external environment. The distribution of group A chemoreceptor genes, as found in the C. jejuni sequenced strains, tlp1-4, 7, 10 and 11 were determined in 33 clinical human and avian isolates.

Results

Group A tlp gene content varied among the strains with genes encoding tlp1 (aspartate receptor, ccaA) and tlp7 present in all strains tested, where as tlp11 was present in only one of our international collection clinical isolates, C. jejuni 520, but was more prevalent (9/13) in the freshly isolated clinical stains from patients who required hospitalisation due to C. jejuni infection (GCH1-17). Relative expression levels of the group A tlp genes were also determined in C. jejuni reference strains NCTC 11168-GS, 11168-O and 81116 using cells grown in vitro at 37°C, 42°C and maintained at room temperature and with cells isolated directly from murine and avian hosts by immune magnetic separation without subsequent culture. Gene expression of tlp genes was varied based on strain, growth conditions and in vivo isolation source. Tlp1, although the most conserved, showed the lowest and most varied mRNA expression and protein production under laboratory conditions. Tlp7 was highly expressed at most conditions tested, and gene expression was not influenced by the tlp7 gene encoding a full length protein or one expressed as separate periplasmic and cytoplasmic domains.

Conclusion

We have shown that chemosensory receptor set variation exists among C. jejuni strains, but is not dependent on the isolation source.

Temporal evolution of susceptibility artifacts from coiled aneurysms on MR angiography: an in vivo canine study

BACKGROUND AND PURPOSE

Intracranial aneurysms treated by coiling have a risk for recurrence, requiring surveillance imaging. MRA has emerged as an attractive technique for postcoiling aneurysm imaging. Previous research has evaluated MR imaging artifacts of the coil mass in vitro. Our aim in this study was to evaluate MR imaging artifacts of coiled aneurysms in vivo with time.

MATERIALS AND METHODS

Four sidewall aneurysms were created in each of 4 dogs. Aneurysms were embolized receiving only 1 type of coils. After embolization, the animals were transferred to MR imaging, which included axial 3D TOF MRA (TEs, 3.5, 5, and 6.9 ms), phase-contrast MRA, and coronal CE-MRA. MR imaging studies were repeated at 1, 4, 6, 8, 14, and 28 weeks. We calculated an OEF: OEF = V(A)/V(CM), where the numerator represents the volume of the MR imaging artifacts and the denominator is the true volume of the coil mass measured by 3D RA.

RESULTS

OEFs were largest immediately after embolization and showed a gradual decay until approximately 4 weeks, when there was stabilization of the size of the artifacts. By 4 weeks, there was mild coil compaction (average coil mass volume decrease of 7.8%); however, the OEFs decreased by 25% after 4 weeks (P < .001).

CONCLUSIONS

MR imaging susceptibility artifacts change with time, being maximal in the postembolization setting and decaying until 4 weeks. The clinical implications of this study are that baseline MRA for comparison with future imaging should be acquired at a minimum of 1 week after the procedure.

The psychosocial impact of food allergy and food hypersensitivity in children, adolescents and their families: a review

Food allergy affects 6% of children but there is no cure, and strict avoidance of index allergens along with immediate access to rescue medication is the current best management. With specialist care, morbidity from food allergy in children is generally low, and mortality is very rare. However, there is strong evidence that food allergy and food hypersensitivity has an impact on psychological distress and on the quality of life (QoL) of children and adolescents, as well as their families. Until recently, the measurement of QoL in allergic children has proved difficult because of the lack of investigative tools available. New instruments for assessing QoL in food allergic children have recently been developed and validated, which should provide further insights into the problems these children encounter and will enable us to measure the effects of interventions in patients. This review examines the published impact of food allergy on affected children, adolescents and their families. It considers influences such as gender, age, disease severity, co-existing allergies and external influences, and examines how these may impact on allergy-related QoL and psychological distress including anxiety and depression. Implications of the impact are considered alongside avenues for future research.

Impact of peanut allergy on quality of life, stress and anxiety in the family

BACKGROUND

Peanut allergy (PA) is known to impact on quality of life (QoL) of the sufferer, but little research has focused on all family members. We therefore sought to establish the impact of PA on QoL and reported anxiety of children with clinically confirmed PA, their parents and older siblings.

METHODS

Forty-six families, who had a child with PA, completed QoL (PedsQL or WHOQOL-BREF), anxiety (SCAS or STAI) and perceived stress (PSS) scales. PA children completed a PA specific QoL questionnaire (Pediatr Allergy Immunol 2003;14:378). Parents and sibling also completed QoL proxy questionnaires for the PA child (PedsQL, Pediatr Allergy Immunol 2003;14:378).

RESULTS

Mothers rated their own psychological (P < 0.01) and physical (P < 0.05) QoL significantly worse than fathers rated theirs, and had higher scores than fathers for anxiety (P < 0.05) and stress (P < 0.001). Children with PA had significantly poorer physical health-related QoL (P < 0.05), QoL within school (P < 0.01) and general QoL (P < 0.05) than their siblings did, and greater separation anxiety (P < 0.05). The majority of differences were between girls with PA and female siblings. Mothers felt that there was a greater impact on QoL for their PA child, compared with that reported by siblings, fathers or the PA children themselves (P < 0.01).

CONCLUSIONS

Mothers report that they have significantly poorer QoL and suffer more anxiety and stress than fathers do; this inter-parental difference may be an important feature of family stress caused by PA. Siblings have a similar view of how QoL affects the PA child as the PA child does, while mothers may possibly overestimate this impact.

MUC1 cell surface mucin is a critical element of the mucosal barrier to infection

Cell surface mucin glycoproteins are highly expressed by all mucosal tissues, yet their physiological role is currently unknown. We hypothesized that cell surface mucins protect mucosal cells from infection. A rapid progressive increase in gastrointestinal expression of mucin 1 (Muc1) cell surface mucin followed infection of mice with the bacterial pathogen Campylobacter jejuni. In the first week following oral infection, C. jejuni was detected in the systemic organs of the vast majority of Muc1(-/-) mice but never in Muc1(+/+) mice. Although C. jejuni entered gastrointestinal epithelial cells of both Muc1(-/-) and Muc1(+/+) mice, small intestinal damage as manifested by increased apoptosis and enucleated and shed villous epithelium was more common in Muc1(-/-) mice. Using radiation chimeras, we determined that prevention of systemic infection in wild-type mice was due exclusively to epithelial Muc1 rather than Muc1 on hematopoietic cells. Expression of MUC1-enhanced resistance to C. jejuni cytolethal distending toxin (CDT) in vitro and CDT null C. jejuni showed lower gastric colonization in Muc1(-/-) mice in vivo. We believe this is the first in vivo experimental study to demonstrate that cell surface mucins are a critical component of mucosal defence and that the study provides the foundation for exploration of their contribution to epithelial infectious and inflammatory diseases.

Does severity of low-dose, double-blind, placebo-controlled food challenges reflect severity of allergic reactions to peanut in the community?

BACKGROUND

The severity of allergic reactions to food appears to be affected by many interacting factors. It is uncertain whether challenge-based reactions reflect the severity of past reactions or can predict future risk.

OBJECTIVE

To explore the relationship of a subject's clinical history of past reactions to the severity of reaction elicited by a low-dose, double-blind, placebo-controlled food challenge (DBPCFC) with peanut.

METHOD

Cross-sectional questionnaire assessment of community-based allergic reactions and low-dose DBPCFC in self-selected peanut-allergic subjects. Reaction severity was assessed using a novel scoring system, taking account of the dose of allergen ingested.

RESULTS

Forty subjects (15 males, 23 children, 23 asthmatics by history) were studied. Only the most recent community reaction predicted the severity of reaction in the DBPCFC, but even this association was weak (r=0.37, P=0.03). Peanut-specific IgE (PsIgE) and skin prick test (SPT) weal size were not associated with community score but PsIgE level correlated well with the challenge score (r=0.6, P=0.001). Asthma did not affect the eliciting dose or challenge score directly but the association of PsIgE and challenge score was stronger in those without asthma (r=0.72, P=0.001) than in those with asthma (r=0.48, P=0.02).

CONCLUSIONS

The scoring system developed appears to improve the sensitivity of assessment of reactions induced by DBPCFC. This is the first prospective study showing an association between PsIgE levels and clinical reactivity in DBPCFC, an effect that is more pronounced in non-asthmatics. This finding has important implications for the clinical care of subjects with food allergy. There is a poor correlation between the severity of reported reactions in the community and the severity of reaction elicited during low-dose DBPCFC with peanut.

Presentation of allergen in different food preparations affects the nature of the allergic reaction - a case series

BACKGROUND

Characterization of fatal and non-fatal reactions to food indicates that the majority of reactions are due to the ingestion of prepared foods rather than the non-processed allergen. In an ongoing study that used a double-blind placebo-controlled food challenge to investigate peanut allergy and clinical symptoms, the observed reaction severity in four of the first six subjects was greater than anticipated. We hypothesized that this was due to differences in the composition of the challenge vehicle.

OBJECTIVE

The aim was to investigate whether the severity of observed challenge reactions would be repeated on re-challenge with a lower fat challenge vehicle.

METHODS

Peanut-allergic subjects were re-challenged with a lower fat recipe after reacting more severely than was anticipated to an initial peanut challenge. Similar challenge vehicle recipes were used, the only difference being the lower fat content (22.9% compared with 31.5%). The peanut content of the two recipes was analysed using RAST inhibition studies and ELISA tests.

RESULTS

Three of four subjects reacted to much smaller doses of peanut protein on re-challenge (mean dose equivalence - 23 times less peanut) with the lower fat recipe. RAST inhibition showed that neither recipe altered epitope recognition. The higher fat recipe required twice as much peanut to cause 50% inhibition. ELISA detected far lower levels of peanut in the higher fat recipe (220 000 parts per million (p.p.m.)) than in the lower fat recipe (990 000 p.p.m.).

CONCLUSION

The fat content of a challenge vehicle has a profound effect on the reaction experienced after allergen ingestion. This is another factor to be considered in assessing the risk of certain foods to food-allergic consumers and adds another dimension to clinical, research and regulatory practice.

Similarities in body image in sisters: the role of sociocultural internalization and social comparison

The sociocultural theory of body image disturbance states that Western women experience pressure from sources such as parents, peers, and the media to maintain thinness. Social comparison theory emphasises the role of comparing one's appearance to others. Body image disturbance; awareness and Internalization of sociocultural messages regarding thinness; and sibling social comparisons were examined in 41 closest-in-age sisters through self-report questionnaires. Sisters showed similar levels of body image disturbance and sociocultural awareness and internalization. Sibling comparisons were negative for younger sisters but neutral or positive for older sisters. Sociocultural internalization predicted body dissatisfaction in both sisters, and body size distortion in younger sisters. Negative sibling comparisons during teenage years predicted body size distortion and body dissatisfaction in younger sisters, and preference for thinness in older sisters.

Chromosome numbers in Compositae. XVIII

Chromosome numbers and other cytogenetic data were determined from microsporocytes in 316 collections including 13 tribes of Compositae, mostly from Africa, Australia, Mexico, Central America, and South America. First reports are provided for 66 species and the genera Cassinia (2n ≈ 14(II)), Feldstonia (2n = 11(II)), Gochnatia (2n ≈ 23(II)), and Pseudoconyza (n = 10). In addition, new chromosome numbers are established at the generic level in Acourtia, Calea, Craspedia, Gnaphalium, Helipterum, Liabum, Leucheria, Smallanthus, Trixis, and Viguiera and at the specific level in 13 additional species.

Comparison of staples and sutures for cardiorrhaphy in traumatic puncture wounds of the heart

The purpose of this study was to compare the traditional method for repair of cardiac lacerations using sutures and pledgets (S/P) with repair using a skin stapling device (SSD) performed by emergency medicine residents. In a prospective, randomized, non-blinded animal study, 20 anesthetized mongrel dogs were instrumented and underwent left lateral thoracotomy, pericardiotomy, and cardiac exposure. In set 1, a standardized 8-mm right ventricular stab wound was made with a #10 scalpel; emergency medicine residents then immediately performed emergent cardiorrhaphy by either S/P (n = 5) or SSD (n = 5) technique. In set 2, 10 dogs received standardized 8-mm right ventricular stab wounds followed by repair and then received a second stab wound to the same right ventricle that was subsequently repaired by the same operator using the alternate technique. All dogs were observed for 60 min for gross blood loss, hemodynamic instability, and integrity of repair. The results demonstrate that SSD cardiorrhaphy was significantly faster (29 +/- 11 sec in set 1; 14 +/- 6 sec in set 2) than S/P repair (201 +/- 10 sec in set 1; 196 +/- 59 sec in set 2). No appreciable differences in blood loss or repair integrity were noted in either group. Two operators in the S/P group suffered needle puncture injuries. In conclusion, cardiorrhaphy by SSD is faster to perform, has similar repair integrity, and has less risk of accidental contaminated needle injury than does traditional S/P repair when performed by emergency medicine residents.

Experience with generally accepted centrifugal pumps: personal and collective experience

BACKGROUND

The data presented are a brief summary of The International Registry for Mechanical Ventricular Assist Pumps and Artificial Hearts and a summary of the personal experience of the Minnesota Thoracic Associates at the Minneapolis Heart Institute with the use of the Sams centrifugal pump from May 1985 to September 1994.

METHODS

Ventricular support with the use of centrifugal pumps for postcardiotomy shock consisted of cannulation of the left atrium and aorta for left ventricular support and the right atrium and pulmonary artery for right ventricular support, or the combination of the two for biventricular support.

RESULTS

The average survival and discharge rate recorded by the National Registry for postcardiotomy syndrome was 25.3%. Our experience at Minnesota Thoracic Associates was 54%. The National Registry reported 45.7% of the patients being weaned from the device or receiving transplants and 25.3% of the patients ultimately discharged from the hospital. Sixty-five percent of the patients in our experience either were weaned from the device or received a transplant for an overall discharge rate of 42%. The average effective hospital cost per survivor was almost $400,000.00.

CONCLUSIONS

It is our belief that when considering the cost analysis of temporary devices, one must conclude that a more economical approach for the treatment of end-stage cardiac disease would be aggressive development of a permanent ventricular assist device.

Operative considerations in implantation of the Perma-Flow graft

The Perma-Flow coronary bypass graft (Possis Medical, Inc, Minneapolis, MN) currently is undergoing expanded clinical trial. From November 1992 through June 1994 we have used this artificial conduit in 8 patients without autologous alternatives. These cases allowed the establishment of a technical basis for successful implantation of this graft. All studied coronary anastomoses are patent.

Mechanical circulatory assistance after heart transplantation

From October 1985 through December 1989, 92 heart transplant procedures were performed in 89 patients. Nine patients (aged 19 to 66 years; 7 male, 2 female) required mechanical circulatory support after transplantation because of primary idiopathic organ failure (n = 2), implant difficulty (2), poor organ quality (2), or acute right heart failure (3). Devices used included the intraaortic balloon pump (6), centrifugal right ventricular assist device (2), left ventricular assist (1), biventricular assists (2), and total artificial heart (1). Two patients required multiple devices. One patient underwent retransplantation. Implant time ranged from 1 to 18 days. One early death occurred owing to right heart failure 6 days after transplantation, 7 hours after removal of a right ventricular assist device, for an overall mortality of 11%. The remaining 8 patients are alive 4 months to 28 months after transplantation. The actuarial 1-year survival of 89% +/- 10% compares well with the survival of 87% +/- 4% for the entire transplant group. All surviving patients are in functional class I. Echocardiographic examination in all patients revealed left ventricular ejection fraction to be normal in 7 and depressed in 1. Extending the criteria for organ donors or difficulty with the implant procedure can lead to early organ failure, which may be reversible with circulatory assistance allowing excellent survival.

Use of a diary technique to investigate psychosomatic relations in atopic dermatitis

Previous research on the relationship between stress and atopic dermatitis has employed retrospective approaches such as interviews and measurement of life events and daily hassles. These studies have yielded inconsistent results. In the current study, 50 atopic dermatitis sufferers completed a diary for a fortnight, recording their daily emotional states and skin condition. The results of meta-analyses indicated that both interpersonal stress and depression were significantly related to changes in skin condition. Meta-analyses of lag sequential analyses indicated that interpersonal stress on Day X predicted skin condition on Day X + 1 and that this relationship was reciprocal. Depression was predicted by the skin condition of the previous day but this relationship was not reciprocal. These results were integrated and their implications for psychosomatic relationships between stress, depression, and atopic dermatitis were discussed.

Comparison of three cold hardiness tests for conifer seedlings

Greenhouse-cultured, container-grown ponderosa pine (Pinus ponderosa var. scopulorum Engelm.), interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), and Engelmann spruce (Picea engelmannii (Parry) Engelm.) were cold acclimated and deacclimated in growth chambers over 19 weeks. Cold hardiness was measured weekly by a whole-plant freeze test and by two quick tissue tests: freeze-induced electrolyte leakage of needles, and differential thermal analysis of buds. The whole-plant freeze test provided results in 7 days, and indicated differences in cold hardiness among stems, buds, and needles. Although the whole-plant freeze test could accurately measure cold hardiness, it was not precise, and it required destructive sampling. Results from freeze-induced electrolyte leakage and differential thermal analysis were available in 2 days and 1 hour, respectively. The freeze-induced electrolyte leakage test was a precise, sensitive and objective predictor of changes or differences in tissue cold hardiness. To determine actual cold hardiness, results could be calibrated to the response of the same tissue in the whole-plant freeze test. The speed and objectivity of differential thermal analysis made this test useful for rapid, general assessment of cold hardiness status, but calibration was difficult, and precision varied.

Experience with the Sarns centrifugal pump as a ventricular assist device

The authors used the Sarns centrifugal pump (Sarns 3M, Ann Arbor, MI) as a ventricular assist device (VAD) in 30 patients between May 1985 and February 1990. Sixteen patients were unweanable from cardiopulmonary bypass at the time of surgery; nine were patients who developed cardiogenic shock postoperatively in the intensive care unit. One was a donor organ failure; one had a failed PTCA; and one an acute myocardial infarction with cardiogenic shock preoperatively. Two patients were bridged to cardiac transplantation. Of the 28 nontransplant candidates, 20 (71.4%) were weaned successfully, 14 (50%) were discharged from the hospital, and 13 (46%) are alive from 1 to 46 months postoperatively (mean, 21.1 months). Three patients received right ventricular support alone; all three were weaned, and two (66.7%) were discharged. Ten patients received left ventricular assistance alone. Six (60%) were weaned, and four (40%) were discharged. Two patients received left ventricular support initially but were taken back for right VAD insertion because of right-sided heart failure; one (50%) is alive. Fifteen patients received biventricular support. Eleven (77.3%) were weaned, and eight (53.3%) were discharged. Patient ages ranged from 19 to 73 years, with a mean age for men of 59 years and 50.5 years for women. There were no thromboembolic events. Various clinical parameters were evaluated to determine effect on weanability and survival. These results show survival equivalent to any other VAD at this time. The centrifugal pump is a convenient and effective means of maintaining ventricular support in individuals who are believed to have salvageable myocardium.

Relationships among cold hardiness, root growth potential and bud dormancy in three conifers

Greenhouse-cultured, container-grown ponderosa pine (Pinus ponderosa var. scopulorum Engelm.), interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) and Engelmann spruce (Picea engelmannii (Parry) Engelm.) were cold acclimated and deacclimated in growth chambers over 19 weeks. Stem cold hardiness, total new root length at 14 days and days to bud break were measured weekly. Relationships among cold hardiness, root growth potential (RGP) and bud dormancy suggest that cold hardiness, which can be measured quickly, could provide a useful basis for estimating the two other parameters. During cold acclimation, there was a lag period in which stem cold hardiness remained at -15 degrees C and RGP was at a minimum, in all three species. Douglas-fir and Engelmann spruce buds remained fully dormant during this lag period. Ponderosa pine buds had no chilling requirement for the loss of dormancy, and reached quiescence during the lag period. Immediately following the lag period, as stem cold hardiness progressed to -22 degrees C, RGP increased to a high plateau in all three species, and Douglas-fir and Engelmann spruce buds approached quiescence. Cold deacclimation and bud development began immediately on exposure to warm, long days, but RGP remained high until stem cold hardiness returned to approximately -15 degrees C. At bud break, cold hardiness and RGP were at the minimum.

Genes specifically expressed at growth arrest of mammalian cells

A subtraction cDNA library enriched for RNA sequences preferentially expressed in growth-arrested cells was prepared. Six cDNA clones were identified, varying in abundance from 2% to 0.0002% of the library and in size from 0.8 to 10 kb. The corresponding mRNAs are downregulated with different kinetics upon induction of growth by serum. The kinetics of induction after serum starvation and density-dependent inhibition of two of these growth-arrest-specific (gas) genes were investigated in more detail. Two cell lines transformed by viral onc genes did not express the two gas genes. The full-length cDNA for one gene has been sequenced and the protein product preliminarily characterized by in vitro translation.

Electrohydraulic shock wave decalcification of stenotic aortic valves: postmortem and intraoperative studies

Decalcification of stenotic aortic valves is limited by the difficulty in removing sufficient calcium to restore valve function without cusp perforation. The present study demonstrates that electrohydraulic shock waves generated by a hand-held lithotriptor fragmented the calcifications contained within the cusps of four necropsy specimens of stenotic aortic valves. The electrohydraulic shock waves appeared to create a cleavage plane between the valve tissue and the fragmented calcific deposits, allowing the fragmented calcified masses to be removed without cusp perforation. Five patients with severe aortic stenosis also underwent successful aortic valve decalcification augmented by electrohydraulic shock waves generated with the hand-held lithotriptor, without significant complication. The shock waves permitted removal, from the aortic valve, of calcium that had not been removed by mechanical means. These results indicate that the addition of electrohydraulic shock waves to mechanical aortic valve decalcification may facilitate successful decalcification in patients undergoing operative treatment for aortic stenosis and may allow patients to avoid the need for aortic valve replacement.

The association of unexplained gastrointestinal bleeding with calcific aortic stenosis

The association of chronic gastrointestinal bleeding and aortic stenosis remains problematical. The cases of 91 patients (age 38 to 80 years) with these disorders who were examined between 1955 and 1975 were reviewed to address this controversy. All patients underwent upper and lower gastrointestinal radiography, small bowel series, and proctoscopy. Other studies were endoscopy in 84 patients, colonoscopy in 61, and visceral angiography in 16. Of the 37 patients who underwent abdominal exploration, 35 (95%) continued to bleed postoperatively, including 8 of 10 patients who had bowel resection for angiodysplasia. Forty patients did not have an abdominal operation, and all have continued to bleed. Sixteen patients (2 of whom had had an abdominal procedure) underwent aortic valve replacement for aortic stenosis. There were 2 intraoperative deaths among these 16 patients. At follow-up, which ranged from 8 to 12 years, only 1 patient who underwent aortic valve replacement had recurrent bleeding secondary to excessive anticoagulation. Thus, overall, gastrointestinal operation was successful in only 5% of patients, but aortic valve replacement was effective in 93%. For unexplained gastrointestinal bleeding associated with aortic stenosis, aortic valve replacement should be considered because of the likelihood of cure.

Ivor Lewis esophagogastrectomy for carcinoma of the esophagus: early and late functional results

One hundred adult patients underwent Ivor Lewis esophagogastrectomy for documented carcinoma of the esophagus from 1980 through 1982. After operation, 7 patients were classified in Stage I, 11 in Stage II, and 82 in Stage III. Major postoperative complications occurred in 27 patients and included pulmonary problems in 11, suture line leak in 9, wound infection in 5, empyema in 4, renal failure in 4, abdominal abscess in 4, bleeding in 2, myocardial infarction in 2, and chylothorax in 1. There were 3 deaths within 30 days of operation. Five-year survival was 85.7% for patients with Stage I disease, 34.1% for patients with Stage II disease (p = .052), and 15.2% for patients with Stage III disease (p = .001). Late morbidity included weight loss in 60 patients, dysphagia in 40, gastroesophageal reflux in 14, and gastroduodenal dumping in 5. Thirty-one patients required postoperative esophageal dilations (mean, 3.4). Most patients, however, were eating without dysphagia at the time of last follow-up or death. We conclude that the Ivor Lewis esophagogastrectomy can be performed with low mortality, can provide adequate palliation, and does result in satisfactory long-term survival for those patients with more favorable postsurgical stages of cancer. These results support the continued use of the Ivor Lewis esophagogastrectomy for treatment of carcinoma of the esophagus.

Repair of ascending aortic dissection. Influence of associated aortic valve insufficiency on early and late results

Operative treatment of dissections of the ascending aorta differs from that for the descending aorta, not only because of the need for cardiopulmonary bypass, but also because of the frequent occurrence of aortic valve insufficiency. To determine the early and late results of operative repair, we have reviewed the case histories of 121 consecutive patients who underwent repair of ascending aortic dissections between 1962 and 1985. Ages ranged from 16 to 79 years (mean 56 +/- 14 years); 54 patients had operation within 2 weeks of onset of symptoms (acute), and the remainder had later repair (chronic). Seventy patients (58%) had clinical evidence of aortic insufficiency at the time of admission. During repair of acute dissection, 10 patients (19%) had aortic valve resuspension and 15 patients (28%) had aortic valve replacement. During repair of chronic dissection, eight patients (12%) had resuspension and 43 patients (64%) had replacement. Overall operative mortality was 22%, significantly higher for patients with acute than for those with chronic dissections (39% versus 9%, p less than 0.01). Operative risk was similar for patients who underwent repair of ascending aortic dissections without valve resuspension or replacement (31%) versus those who had repair with aortic valve resuspension (17%) or replacement (17%). During a follow-up period ranging from 1 to 208 months, aortic regurgitation developed in only two patients who did not have aortic insufficiency at the time of repair. Late aortic regurgitation necessitating reoperation developed in one of the 15 survivors who had aortic valve resuspension. Eight patients undergoing aortic valve replacement had complications of their prostheses, including one periprosthetic leak and four mechanical failures. We conclude that resuspension or replacement of the aortic valve does not increase the risk of repair of ascending aortic dissections. Selective management of aortic insufficiency (with valve repair whenever possible) yields satisfactory long-term results.

Further Sesquiterpene Lactones from Eupatorium altissimum

A reinvestigation of the aerial parts of EUPATORIUM ALTISSIMUM afforded, in addition to several, previously isolated sesquiterpene lactones, five new ones. The structures of these were elucidated by highfield (1)H-NMR spectroscopy.

Further beta-Cyperone Derivatives from Haplopappus freemontii

The roots of HAPLOPAPPUS FREEMONTII afforded in addition to the known 8-oxo-beta-cyperone two further derivatives. The structures were elucidated by highfield (1)H-NMR spectroscopy.

Bisabolone derivatives and sesquiterpene lactones from centaurea species

The investigation of three CENTAUREA species collected in Argentina afforded, in addition to several known sesquiterpene lactones, a new guaianolide, a germacranolide, and two bisabolone derivatives. The structures were elucidated by highfield (1)H-NMR spectroscopy.

Concomitant mitral valve repair or replacement and coronary revascularization

Patients undergoing combined mitral valve replacement and coronary revascularization require surgical skill and especially judgment for optimal results. In our hands, cardioplegia has not been a pivotal event in affecting survival, and this probably relates to our previous philosophy of limiting the hypothermic ischemic episodes to 15-minute intervals. Currently, we believe that valve repair, when it can be accomplished, is preferable to valve replacement, especially in the patient with ischemic mitral valve disease. When repair cannot be satisfactorily accomplished, replacement with retention of the posterior leaflet seems clinically to be associated with less disturbance of left ventricular function.

Prognostic factors and surgical treatment of partial atrioventricular canal

In this study we sought to determine the prognostic factors that influence early and late survival after repair of partial atrioventricular canal and the need for reoperation. From January 1962 to January 1984, 199 patients underwent correction of partial atrioventricular canal. There were 73 male and 126 female patients, ranging in age from 5 months to 71 years (mean 11.2 years). Total 30 day operative mortality was 5.5%. Since 1980, the mortality has declined to 3%. Significant determinants of operative mortality were congestive heart failure, cyanosis, failure to thrive, age less than 4 years, and moderate-to-severe mitral valve insufficiency (p less than .01). Sex, cardiomegaly, radiographically increased pulmonary vasculature, intraoperative postrepair right ventricular-to-left ventricular pressure ratio, and pulmonary-to-systemic flow ratio were not significant in determining early mortality. Follow-up ranged from 1 to 21.4 years (mean 15.2). There were seven late deaths, primarily in older patients from atherosclerotic disease or malignancy. Late survival was 98% at 1 year and 96% at 20 years. Reoperation was performed on 18 patients, 15 for mitral incompetence, and three for subaortic stenosis. The need for reoperation correlated with severity of postrepair mitral insufficiency. Longterm survival is excellent after repair of the partial form of atrioventricular canal.

Mechanical decalcification of the aortic valve

Thromboembolism and anticoagulant-related complications secondary to prosthetic aortic valve replacement constitute a significant risk (28% at 5 years). From 1978 through 1984, decalcification of the aortic valve was performed in 8 patients who were undergoing coronary artery revascularization. Preoperative gradients of between 30 and 80 mm Hg (mean, 50 mm Hg) were abolished after operation. To determine the viability of decalcification, the records of 84 additional patients who had undergone this procedure between 1959 and 1978 were reviewed (86% before 1965). There were 60 male and 32 female patients ranging from 14 to 74 years old (mean, 49 years). The cause of the calcification was a bicuspid valve in 32 patients (35%), senile calcification in 9 (10%), and rheumatic fever in 50 (54%); the cause in 1 patient was unknown. Thirty-day mortality was 13%. Follow-up was 98% complete and ranged from 6 months to 22 years (mean, 7 years). Aortic valve replacement was subsequently required in 25 patients. Freedom from reoperation at 1, 5, 10, and 15 years was 98%, 75%, 43%, and 26%, respectively, for patients with rheumatic valves compared with 97%, 76%, 57%, and 51%, respectively, for those with bicuspid valves. Survival for patients with rheumatic valves at 1, 5, 10, 15, and 20 years was 93%, 70%, 48%, 40%, and 35%, respectively, compared with 100%, 66%, 57%, 46%, and 46% for patients with bicuspid valves. At follow-up, 61% of the patients were in New York Heart Association Functional Class I or II. Causes of late death were valve related (30%), congestive heart failure (27%), and myocardial infarction (24%).(ABSTRACT TRUNCATED AT 250 WORDS)

New pseudoguaianolides from Gaillardia megapotamica var. scabiosoides

The aerial parts of Gaillardia megapotamica var. scabiosoides afforded known pseudoguaianolides and three new ones. Furthermore, a new guaianolide and an acetylenic sulfoxide were isolated.

Primary chest wall tumors: factors affecting survival

Between 1955 and 1975, chest wall resection was done in 90 patients for primary chest wall tumors. Ages ranged from 8 to 96 years (mean, 44.3 years). A painful mass was the most common sign and symptom. Eighty-two tumors (91.1%) were located in the lateral chest wall and eight, in the anterior thorax. The tumor was malignant in 71 patients (78.9%) and benign in 19. All patients with benign tumors had complete excision and are currently free from disease. Malignant fibrous histiocytoma, chondrosarcoma, and rhabdomyosarcoma constituted 62% of the malignant neoplasms. Most malignancies were treated by wide resection. There were no thirty-day operative deaths. Overall 1-, 5-, and 10-year survival was 89%, 57%, and 49%, respectively. Recurrent tumor developed in 37 patients (52%); 5-year survival, however, was only 17% after recurrence. Cell type and extent of invasion significantly influenced survival. Both chondrosarcoma and rhabdomyosarcoma had a better prognosis than malignant fibrous histiocytoma (p less than 0.05). We conclude that early resection is the treatment of choice for primary malignant chest wall tumors and that development of recurrent disease is an ominous event.

Early and late results following repair of dissections of the descending thoracic aorta

Management of dissections of the descending thoracic aorta remains controversial, especially with regard to timing and method of repair. To clarify these and other issues we have reviewed our total experience with repair of descending aortic dissections between 1962 and 1983. The 44 men and 20 women had a mean (+/- SEM) age of 59 +/- 2 years (range, 19 to 83 years), and in all patients the dissection originated in and was limited to the aorta distal to the left carotid artery (Stanford type B, DeBakey types IIIa and IIIb). Twenty-nine patients underwent operation within 2 weeks of the onset of symptoms (acute), and the remainder had later repair (chronic). During repair, circulation distal to the aortic cross-clamp was supported with cardiopulmonary bypass or shunt in two thirds of patients. Overall, 18 deaths occurred less than or equal to 30 days postoperatively (operative risk 28%), and risk was higher in acute (45%) than in chronic (14%) dissections. Operative risk was not significantly related to protection of the distal circulation. The most serious postoperative complication was spinal cord ischemia manifested by paraplegia in five patients (8%) and transient or permanent paraparesis in six patients (9%). Risk of spinal cord ischemia was significantly lower in patients who had protection of the distal circulation during operative repair (8% vs. 44%, p = 0.003). Late survival, including hospital deaths, was 49% +/- 7% at 5 years after operation; 22 of the 46 patients who survived repair were found to have aneurysms involving the thoracic and/or abdominal segments of the aorta. Our results indicate that repair of chronic dissection of the thoracic aorta has a lower operative risk than repair of acute dissections, and initial medical management of acute dissection may be indicated if no early complications occur. Risk of spinal cord ischemia is significantly reduced by cardiopulmonary bypass or shunt and is preferred over aortic cross-clamping alone. Finally, these patients require careful long-term follow-up because of the high incidence of residual or recurrent aortic aneurysms.

Renal artery graft-to-duodenum fistula: unusual presentation of a recurrent flank abscess

Perhaps the most devastating complication of a prosthetic vascular graft is the formation of an aortoenteric fistula. Most reports have dealt with fistulas between the aortic graft and the duodenum, although any revascularized vessel with prosthetic material can be the site of an enteric fistula. We report an unusual case in which a renal artery previously revascularized with a silk prosthetic graft developed a fistula to the duodenum 16 years later. Whether the prosthetic graft is in the aortic position or to a visceral vessel, when a fistula develops the only acceptable treatment is complete removal of the graft and revascularization with autogenous tissues, if necessary.