bluuebunny/crossref_metadata_2025 huggingface dataset:
Post‐proteomic identification of a novel phage‐encoded streptodornase, Sda1, in invasive M1T1 Streptococcus pyogenes
Authors: Aziz Ramy K. , Ismail Shehab A. , Park Hee‐Won , Kotb Malak
Published: September 2004

The M1T1 strain remains the most frequently isolated strain from group A streptococcal (GAS) infection cases worldwide. We previously reported that M1T1 differs from the fully sequenced M1 SF370 strain. To better understand the reason for the persistence and increased virulence of M1T1, we analysed its secreted proteome and identified two virulence proteins that are not present in the sequenced M1 SF370 strain: streptococcal pyrogenic exotoxin A (SpeA) and a streptodornase D (SdaD) homologue. In the present study, we determined the nucleotide sequence of the M1T1 streptodornase and found that its deduced amino acid sequence is highly similar to other streptococcal streptodornases, and is most closely related to the SdaD of GAS strain M49. M1T1 Sda shares two highly conserved domains with several DNases and putative DNases in streptococci; however, it possesses a unique C‐terminal amino acid sequence. Thus, we named the protein Sda1, and we detected the presence of the sda1 gene in 16 M1T1 clinical isolates. The cloned and expressed Sda1 degrades both streptococcal and mammalian DNA at physiological pH. Amino acid similarity analyses of known GAS deoxyribonucleases suggest that Sda1 may be a chimeric protein created through recombination events. Moreover, a natural mutation that resulted in longer Sda1 and SdaD as compared to other GAS DNases was found to confer increased activity on the protein. Analysis of the sequences flanking sda1 determined that it is carried by a prophage or a prophage‐like element inserted in the tRNA‐Ser gene of M1T1 GAS. Ongoing studies in our laboratory aim to determine the contribution of Sda1 to the virulence of this globally disseminated M1T1 strain.
Widespread distribution of a lexA‐regulated DNA damage‐inducible multiple gene cassette in the Proteobacteria phylum
Authors: Abella Marc , Erill Ivan , Jara Mónica , Mazón Gerard , Campoy Susana , Barbé Jordi
Published: September 2004

The SOS response comprises a set of cellular functions aimed at preserving bacterial cell viability in front of DNA injuries. The SOS network, negatively regulated by the LexA protein, is found in many bacterial species that have not suffered major reductions in their gene contents, but presents distinctly divergent LexA‐binding sites across the Bacteria domain. In this article, we report the identification and characterization of an imported multiple gene cassette in the Gamma Proteobacterium Pseudomonas putida that encodes a LexA protein, an inhibitor of cell division (SulA), an error‐prone polymerase (DinP) and the alpha subunit of DNA polymerase III (DnaE). We also demonstrate that these genes constitute a DNA damage‐inducible operon that is regulated by its own encoded LexA protein, and we establish that the latter is a direct derivative of the Gram‐positive LexA protein. In addition, in silico analyses reveal that this multiple gene cassette is also present in many Proteobacteria families, and that both its gene content and LexA‐binding sequence have evolved over time, ultimately giving rise to the lexA lineage of extant Gamma Proteobacteria.
Identification and characterization of the Pasteurella multocida toxin translocation domain
Authors: Baldwin Michael R. , Lakey Jeremy H. , Lax Alistair J.
Published: September 2004

The Pasteurella multocida toxin (PMT) is a potent mitogen which enters the cytosol of eukaryotic cells via a low pH membrane translocation event. In common with the Escherichia coli cytotoxic necrotizing factor 1 (CNF1), the core of the PMT translocation domain is composed of two predicted hydrophobic helices (H1 – residues 402–423, H2 – 437–457) linked by a hydrophilic loop (PMT‐TL – 424–436). The peptide loop contains three acidic residues (D425, D431 and E434), which may play a role equivalent to D373, D379 and E382/383 in CNF1. To test this hypothesis, a series of point mutants was generated in which acidic residues were mutated into the permanently charged positive residue lysine. Individual mutation of D425, D431 and E434 each caused a four‐ to sixfold reduction in toxin activity. Interestingly, mutation of D401 located immediately outside the predicted helix–loop–helix motif completely abolished toxin activity. Individual mutations did not affect cell binding nor greatly altered toxin structure, but did prevent translocation of the surface‐bound proteins into the cytosol after a low pH pulse. Moreover, we demonstrate using an in vitro assay that PMT undergoes a pH‐dependent membrane insertion.
A network of net‐workers: report of the Euresco conference on ‘Bacterial Neural Networks’ held at San Feliu (Spain) from 8 to 14 May 2004
Authors: Hellingwerf Klaas J.
Published: September 2004

In May 2004, over 100 bacteriologists from 19 different countries discussed recent progress in identification and understanding of individual signal transfer mechanisms in bacteria and in the mutual interactions between these systems to form a functional living cell. The meeting was held in San Feliu and supported by ESF and EMBO. In part through the extensive sequencing efforts of the past few years, the bulk of the bacterial signal transfer systems have been resolved and their detailed characterization is revealing such characteristics as signal specificity, signalling rate constants, molecular interaction affinities, subcellular localization, etc., which should provide a solid basis to a computational extension of this field of studies. In parallel, the new genomics techniques are providing tools to characterize the way a collection of such systems interact in an individual cell, to give rise to ‘life’. Systems theory provides rational and convenient ways to bring order to the wide range of observables thus obtained. Ultimately, the performance of engineered design will have to prove whether or not we know enough about the processes involved.
Clinical Paratuberculosis as a Cause for Higher Culling Rate in Cows with Left Displaced Abomasum and Diarrhoea in a Holstein Dairy Herd
Authors: Kasravi R. , Nowrouzian I.
Published: September 2004

The present report identifies a statistically significant (P < 0.001) higher postoperative culling rate in cows with left displaced abomasum (LDA) exhibiting diarrhoea, compared with cows with LDA and normal faeces from a large Holstein dairy herd (odds ratio = 34). Paratuberculosis was histopathologically confirmed in 77.0% of cows with LDA exhibiting diarrhoea.
Early and Cost‐Effective Identification of High Risk/Priority Control Areas in Foot‐and‐Mouth Disease Epidemics
Authors: Rivas A. L. , Schwager S. J. , Smith S. , Magri A.
Published: September 2004

Geo‐referenced data from the 2001 Uruguayan foot‐and‐mouth disease (FMD) epidemic were explored to assess whether spatial analysis could lead to cost‐benefit based policies. Four variables were analysed: (i) location and size of 4022 individual rural land parcels, of which 574 were infected over 60 days, (ii) animal density, (iii) percentage of dairy farms per county, and (iv) road density. Each variable was categorized into two to five classes (e.g. small/medium/large) and the proportion of cases per class reported at days 1–3 of the epidemic was compared with that reported at days 4–6. A higher proportion of cases was found at days 4–6 than at days 1–3 in areas with: small and medium size land parcels, high animal density, >20% farms specialized in dairy production, and high road density (P < 0.03 for each). Each of these classes showed a greater proportion of cases at days 7–60 than the proportion of the total territory covered by each class's area (early case concentration ratios: 1.14–1.37). Land parcel clusters were indicated by Moran's I‐test (P < 0.01). A new region was constructed by intersecting the four spatial classes associated with higher proportions of cases at days 4–6. At days 7–60, this region included 50.4% of all cases and represented 30.6% of the territory under study (final case concentration ratio: 1.65). The final area per case in this region was at least 33% lower and covered at least 45% less territory than any of the four single‐variable approaches. Bio‐statistical, multivariate spatial analysis of early cases may greatly increase the efficiency of epidemiologic policy.
Influence of Methods for Trichinella Detection in Pigs from Endemic and Non‐endemic European Region
Authors: Nöckler K. , Hamidi A. , Fries R. , Heidrich J. , Beck R. , Marinculic A.
Published: September 2004

A total of 1401 German and 226 Croatian pigs raised either indoors or outdoors were tested for Trichinella infection by direct and indirect detection methods. A 10 g sample of diaphragm were examined for muscle larvae by the artificial digestion method; the species was determined by multiplex polymerase chain reaction (PCR). For detection of anti‐Trichinella IgG, serum samples diluted 1:100, and meat juice samples diluted 1:10, were tested by enzyme‐linked immunosorbent assay. All German pigs and those Croatian pigs raised indoors proved to be Trichinella‐negative by all methods. Muscle larvae were detected in a total of eleven of the Croatian pigs, which were raised on small outdoor farms. For eight isolates, PCR results demonstrated that recovered larvae were Trichinella spiralis. Anti‐Trichinella‐IgG was detected in serum and meat juice of digestion positive animals when the worm burdens exceeded 0.38 larvae per gram of muscle. Positive results in Croatian pigs indicate a higher risk of infection for outdoor farming in areas where Trichinella is endemic. Results of direct and indirect detection were compared and are discussed with special regard to specificity and sensitivity of methods.
Petrogenesis of the Tanzawa plutonic complex, central Japan: Exposed felsic middle crust of the Izu–Bonin – Mariana arc
Authors: KAWATE SHINICHI , ARIMA MAKOTO
Published: September 2004

The Miocene Tanzawa plutonic complex, consisting mainly of tonalite intrusions, is exposed at the northern end of the Izu–Bonin – Mariana (IBM) arc system as a consequence of collision with the Honshu Arc. The Tanzawa plutonic rocks belong to the calc‐alkaline series and exhibit a wide range of chemical variation, from 43 to 75 wt% SiO2. They are characterized by relatively high Ba/Rb and Ce/Nb ratios, and low abundances of K2O, LIL elements, and rare earth elements (REE). Their petrographic and geochemical features indicate derivation from an intermediate parental magma through crystal fractionation and accumulation processes, involving hornblende, plagioclase, and magnetite. The Tanzawa plutonic complex is interpreted to be the exposed middle crust of the IBM arc, which was uplifted during the collision. The mass balance calculations, combining data from melting experiments of hydrous basaltic compositions at lower‐to‐middle crustal levels, suggest that parental magma and ultramafic restite were generated by dehydration partial melting (∼ 45% melting) of amphibolite chemically similar to low‐K tholeiitic basalt. Partial melting of hydrated mafic lower crust might play an important role in felsic middle‐crust formation in the IBM arc.
Implications from the seismic crustal structure of the northern Izu–Bonin arc
Authors: TAKAHASHI NARUMI , SUYEHIRO KIYOSHI , SHINOHARA MASANAO
Published: September 2004

The results of a controlled source seismic reflection–refraction experiment carried out in 1992 reveal the following characteristics of the northern Izu–Bonin (Ogasawara) oceanic island arc–trench system. (1) The crust rapidly thickens from the Shikoku back‐arc basin to the arc, is thickest beneath the active rifts, and then gradually thins to the forearc. The thickness of the crust beneath the arc rift zone and the back‐arc basin are ∼ 20 km and 8 km, respectively. (2) The Moho vanishes beneath the forearc. Velocities rapidly decrease eastwards beneath the inner trench wall. (3) The velocity of the lower crust of the arc and the back‐arc basin is 7.1–7.3 km/s. This velocity is higher than the typical oceanic lower crust whose velocity is ∼ 6.7 km/s. (4) The velocity of the middle crust of the arc is ∼ 6 km/s. This layer does not exist beneath the back‐arc basin. (5) A slight difference in the velocity gradient of the middle crust exists between the arc rift zone and the forearc. Based on these findings and previous studies, it is inferred that: (i) the middle crust is probably granitic rock and formed in more than two episodes; (ii) the lower crust formed by igneous underplating which may also have affected part of the back‐arc basin; and (iii) the root of the serpentinite diapir on the inner trench wall is a low‐velocity mantle wedge that was probably caused by large amounts of water released from the subducting Pacific plate at depths shallower than 30 km.
Nature and growth rate of the Northern Izu–Bonin (Ogasawara) arc crust and their implications for continental crust formation
Authors: TAIRA ASAHIKO , SAITO SANEATSU , AOIKE KAN , MORITA SUMITO , TOKUYAMA HIDEKAZU , SUYEHIRO KIYOSHI , TAKAHASHI NARUMI , SHINOHARA MASANAO , KIYOKAWA SCHOICHI , NAKA JIRO , KLAUS ADAM
Published: September 2004

The bulk composition of the continental crust throughout geological history is thought by most previous workers to be andesitic. This assumption of an andesitic bulk composition led to an early hypothesis by Taylor (1967) that the continental crust was created by arc magmatism. This hypothesis for the origin of continental crust was challenged by several authors because: (i) the mean rate of arc crust addition obtained by Reymer and Schubert (1984) is too small to account for some certain phases of rapid crustal growth; and (ii) the bulk composition of ocean island arcs, the main contributor to the Archean and early Proterozoic crust, is basaltic rather than andesitic (Arculus 1981; Pearce et al. 1992). New data from the Northern Izu–Bonin arc are presented here which support the Taylor (1967) hypothesis for the origin of the continental crust by andesitic arc magma. A geological interpretation of P wave crustal structure obtained from the Northern Izu–Bonin arc by Suyehiro et al. (1996) indicates that the arc crust has four distinctive lithologic layers: from top to bottom: (i) a 0.5–2‐km‐thick layer of basic to intermediate volcaniclastic, lava and hemipelagite (layer A); (ii) a 2–5‐km‐thick basic to intermediate volcaniclastics, lavas and intrusive layer (layer B); (iii) a 2–7‐km‐thick layer of felsic (tonalitic) rocks (layer C); and (iv) a 4–7‐km‐thick layer of mafic igneous rocks (layer D). The chemical composition of the upper and middle part of the northern Izu–Bonin arc is estimated to be similar to the average continental crust by Taylor and McLennan (1985). The rate of igneous addition of the Northern Izu–Bonin arc since its initial 45‐Ma magmatism was calculated as 80 km3/km per million years. This rate of addition is considered to be a reasonable estimate for all arcs in the western Pacific. Using this rate, the global rate of crustal growth is estimated to be 2.96 km3/year which exceeds the average rate of crustal growth since the formation of the Earth (1.76 km3/year). Based on this estimate of continental growth and the previously documented sediment subduction and tectonic erosion rate (1.8 km3/year, von Heune & Scholl 1991), several examples of growth curves of the continental crust are presented here. These growth curves suggest that at least 50% of the present volume of the continental crust can be explained by arc magmatism. This conclusion indicates that arc magmatism is the most important contributor to the formation of continental crust, especially at the upper crustal level.
Asymmetric rifting of the northern Mariana Trough
Authors: Yamazaki Toshitsugu , Murakami Fumitoshi
Published: September 2004

The evolution of rifting in the northern Mariana Trough was studied, based on single‐channel seismic reflection profiles and heat flow. The rift showed structural asymmetry. The northernmost part of the Mariana Trough at 24°N, just south of Minami‐Iwojima Island, is now in an incipient rifting stage and shows a half‐graben structure. The arc crust just behind the volcanic front is cut by a few major east‐dipping normal faults. The major faults extend southward behind the Hiyoshi seamounts around 23°30′N. The rift develops to a full‐graben stage at ∼ 23°N, where the width of the trough increases to 80 km. The trough is comprised of several faulted and tilted blocks of island‐arc crust. Maximum subsidence occurs along a row of small grabens on the eastern margin of the trough. These grabens are separated by arc volcanoes, and their depths increase southward from 2500 m at 23°20′N to 4500 m at 22°N. The strike of each graben is north‐northwest–south‐southeast, which is close to the trend of the remnant West Mariana Ridge, but oblique to the active Mariana arc. Crustal extension becomes concentrated along the eastern margin of the trough as rifting progresses. The transition from rifting to sea floor spreading may occur at ∼ 22°N, where the width of the trough is ∼ 120 km. The possible spreading center lies along the southern extension of the grabens on the eastern margin. The period of back‐arc rifting before spreading begins is estimated to be less than 3 million years. Heat flow is asymmetric in the rift. High heat flow was observed only in or close to the row of grabens along the eastern margin of the trough. The asymmetric pure shear extension model fits the observed heat flow distribution better than the simple shear extension model.
Causes of spatial compositional variations in Mariana arc lavas: Trace element evidence
Authors: PEATE DAVID W. , PEARCE JULIAN A.
Published: September 2004

New inductively coupled plasma mass spectrometry (ICP‐MS) trace element data are presented on a suite of arc lavas from the northern Mariana and southern Bonin island arcs. The samples were dredged from seamounts in the Central Island Province (CIP), the Northern Seamount Province (NSP) and the Volcano Arc (VA), and they range in composition from low‐K tholeiites to shoshonites. Previous studies on these samples concluded that the primary compositional control was two‐component mixing between a fluid‐metasomatized mid‐ocean ridge basalt (MORB) source and an enriched, ocean island basalt (OIB)‐like, mantle component, with subducted sediment material playing a secondary role. However, the new trace element data suggest that the compositional variations along the Mariana arc can be better explained by the addition of spatially varying subduction components to a spatially varying mantle source. The data suggest that the subduction component in the CIP and VA is dominated by aqueous fluids derived from altered oceanic crust and a pelagic sediment component, while the subduction component in the NSP is dominated by more silicic fluids derived from volcanogenic sediments as well as from pelagic sediment and altered oceanic crust. The mantle wedge in the CIP and VA is depleted relative to a normal mid‐ocean ridge basalt source by loss of a small melt fraction, while the mantle wedge in the NSP is enriched either by possible gain of a small melt fraction or addition of a sediment‐derived melt. Because the subduction of seamounts controls the arc and back‐arc geometries, so the concomitant variation between subducted material and mantle composition may be no coincidence. The high field strength element (HFSE) data indicate a high degree of melting (∼ 25–30%) throughout the arc, ∼ 10% of which may be attributed to decompression and ∼ 20% to fluid addition.
Temporal evolution of the Mariana arc during rifting of the Mariana Trough traced through the volcaniclastic record
Authors: Clift PeterD. , Lee Jongman
Published: September 2004

The sedimentary sequences that accumulate around volcanic arcs may be used to reconstruct the history of volcanism provided the degree of along‐margin sediment transport is modest, and that reworking of old sedimentary or volcanic sequences does not contribute substantially to the sediment record. In the Mariana arc, the rare earth and trace element compositions of ash layers sampled by Deep Sea Drilling Project (DSDP) site 451 on the West Mariana Ridge, and sites 458 and 459 on the Mariana Forearc, were used to reconstruct the evolution of the arc volcanic front during rifting of the Mariana Trough. Ion microprobe analysis of individual glass shards from the sediments shows that the glasses have slightly light rare earth element (LREE)‐enriched compositions, and trace element compositions typical of arc tholeiites. The B/Be ratio is a measure of the involvement of subducted sediment in petrogenesis, and is unaffected by fractional crystallization. This ratio is variable over the period of rifting, increasing up‐section at site 451 and reaching a maximum in sediments dated at 3–4 Ma, ∼ 3–4 million years after rifting began. This may reflect increased sediment subduction during early rifting and roll‐back of the Pacific lithosphere. Parallel trends are not seen in the enrichment of incompatible high field strength (HFSE), large ion lithophile (LILE) or rare earth elements (REE), suggesting that flux from the subducting slab alone does not control the degree of melting. Re‐establishment of arc volcanism on the trench side of the basin at ca 3 Ma resulted in volcanism with relative enrichment in incompatible REE, HFSE and LILE, although these became more depleted with time, possibly due to melt extraction from the mantle source as it passed under the developing back‐arc spreading axis, prior to melting under the volcanic front.
Early history of the Izu–Bonin – Mariana arc system: Evidence from Belau and the Palau Trench
Authors: HAWKINS JAMES W. , CASTILLO PATERNO R.
Published: September 2004

Volcanic rocks of the Kyushu–Palau Ridge (KPR) from Deep Sea Drilling Project (DSDP) site 448 and from Belau comprise a low‐to‐medium‐K arc tholeiitic series. Belau rocks include (probable) Mid‐Eocene low‐Ca type‐3 boninite and pre‐Early Oligocene–Early Miocene low‐K arc tholeiitic basalt, basaltic andesite, andesite and dacite. Palau Trench samples include sparsely phyric high‐Mg, ‐Cr and ‐Ni rocks which resemble the Belau boninite and Izu–Bonin – Mariana (IBM) system boninites. The high‐Mg Palau Trench samples also resemble other primitive arc lavas (e.g. arc picrites). Their chemistry suggests an origin involving steep thermal gradients in multiply depleted mantle. Subduction of hot, young lithosphere under a young hot upper plate is postulated to explain this occurrence. The KPR is inferred to be the source of Eocene boninite and arc tholeiitic terranes presently in forearc regions of the IBM system. A model is presented here showing how many IBM boninites may have originated in a small area near Belau. These have migrated eastward by episodic back‐arc opening accompanying eastward migration of arcs and trenches. Oldest known KPR rocks (ca 47.5 Ma at DSDP site 296), and presumed KPR‐derived exotic terranes of Guam (ca 43.8 Ma), presage the postulated Eocene (ca 42–43 Ma) change in Pacific plate motion invoked as the cause of subduction initiation at the KPR. The KPR has been rotated more than 40° clockwise since the Eocene, thus the age mismatch may indicate a different tectonic style, for example transtension or transpression, in earliest KPR history.
40Ar/ 39Ar and K–Ar geochronological age constraints for the inception and early evolution of the Izu–Bonin – Mariana arc system
Authors: COSCA MICHAELA. , ARCULUS RICHARDJ. , PEARCE JULIANA. , MITCHELL JOHNG.
Published: September 2004

K–Ar and 40Ar/39Ar dates are presented for locations in the Izu–Bonin – Mariana (IBM) forearc (Ocean Drilling Program (ODP) sites 786 & 782, Chichijima, Deep Sea Drilling Program (DSDP) sites 458 & 459, Saipan), and Palau on the remnant arc of the Kyushu–Palau Ridge. For a number of these locations, the 40Ar/39Ar plateau and 36Ar/40Ar versus 39Ar/40Ar isochrons give older ages than the K–Ar results. The most important results are: (i) at site 786, initial construction of the proto‐IBM (now forearc) basement occurred at least by ca 47–45 Ma, consistent with the age of the immediately overlying sediments (middle Eocene nannofossil Zone CP13c); the younger pulse of construction dated at ca 35 Ma by K–Ar could not be confirmed by 40Ar/39Ar analysis; (ii) 40Ar/39Ar ages for the initial construction of the Mariana portion of the IBM system are as old as those of the Izu–Bonin portion, for example at site 458, initial construction commenced at least by ca 49 Ma and at ca 47 Ma at Saipan (Sankakayuma Formation); and (iii) a combination of K–Ar and 40Ar/39Ar ages indicate continued boninite magmatism in the Izu–Bonin forearc (and remnant arc at Palau) until ca 35 Ma. Subduction inception including boninite series rocks along most of the exposed length of the IBM system, clearly preceded by some 5 million years the Middle Eocene (ca 43.5 Ma) change in Pacific plate motion. Boninitic series magmatism persisted at locations now exposed in the forearc for ∼ 15 million years after arc inception concurrently with low‐K tholeiitic series eruptions from a subaerial arc system, established at ≥ 40 Ma, on the Kyushu–Palau Ridge. For the Mariana portion of the IBM system, reconstruction of the proto‐arc places this activity adjacent to the concurrent but orthogonally spreading Central Basin Ridge of the West Philippine Basin. It is possible that a combination of subduction of a young North New Guinea Plate beneath newly created back‐arc basin crust may account for some of the features of the Mariana system. It is clear, however, that the understanding of the processes of subduction initiation and early IBM arc development is incomplete.
Mucinous cystadenoma of the appendix
Authors: Iswariah Harish , Metcalfe Matthew , Lituri Darren , Maddern Guy J.
Published: September 2004

Mucinous neoplasms of the Appendix are rare conditions, usually diagnosed intraoperatively or postoperatively on the pathology report. They have an association with colonic and ovarian neoplasms, and spillage can result in pseudomyxoma peritonei. While appendicectomy is adequate treatment for cystadenomas, cystadenocarcinomas require a right hemicolectomy. Open approach is recommended for the surgical treatment of these lesions.
Splenectomy in severe haemophilia
Authors: Caldicott David , Bonnin Robert , Lloyd John , Day Peter
Published: September 2004

‘I am disposed to regard the following rule as imperative: that no cutting operation be undertaken unless the patient's life be in danger for want of that particular operation.’−A Treatize on Haemophilia Sometimes Called the Hereditary Haemorrhagic Diathesis J. W. Legg, 18721

The management of any surgical condition in a haemophilia patient is a challenging problem for the surgeon. It is particularly difficult if the patient presents in extremis, with no apparent cause for their collapse. We report a case of successful management of spontaneous splenic rupture in a severe haemophiliac, and review the literature associated with this unusual condition.
Mirizzi syndrome: noteworthy aspects of a retrospective study in one centre
Authors: Tan Kok‐Yang , Chng Hong‐Chee , Chen Cosmas Yun‐Yin , Tan Su‐Ming , Poh Beow‐Keong , Hoe Michael Nan‐Yuh
Published: September 2004

Background:  Mirizzi syndrome is uncommon. It is, however, clinically important, as it is associated with an increased incidence of bile duct injury and demands more complex surgical techniques.

Methods:  A retrospective review of 24 consecutive cases of Mirizzi syndrome that arose between January 1997 and July 2002 was performed. A total of 1881 cholecystectomies were performed during that period.

Results:  Of the 24 patients, 19 (79.2%) had Mirizzi type I, four (16.7%) had type II, while one (4.2%) had type III disease. Only 54.2% of patients were symptomatic prior to presentation. One‐third of patients had normal liver function tests. Ultrasonography and computed tomography were not helpful in diagnosing this entity. Endoscopic retrograde cholangiopancreatography (ERCP) was useful to identify cholecystocholedochal fistulas and to allow therapeutic endoscopic stenting but failed to pick up the syndrome in half of the patients. Inadvertent bile duct injury occurred in four patients (16.7%), all occurred in patients without a preoperative diagnosis. Three of the four injuries occurred during operations by a senior registrar rather than a consultant. Mirizzi type I was managed with either total or subtotal cholecystectomy, while types II and III cases were managed with either T‐tube insertion or biliary bypass procedures. Bile duct injury was managed with T‐tube successfully in one patient while the rest went on to biliary bypass operations. All except one patient had good functional outcomes on follow up.

Conclusion:  The preoperative diagnosis of Mirizzi syndrome is a challenge. Only constant vigilance during intraoperative dissection of the Calot's triangle will reduce the incidence of bile duct injury in Mirizzi syndrome that can occur in both open and laparoscopic surgery.
Outcomes in sinonasal mucosal melanoma
Authors: Martin Jarad M. , Porceddu Sandro , Weih LeAnn , Corry June , Peters Lester J.
Published: September 2004

Background:  The present paper assesses treatment outcomes in a series of 20 patients with sinonasal mucosal melanoma (SNMM) over 11 years.

Methods:  All patients who presented to a single institution between 1991 and 2002 with a diagnosis of SNMM had their treatment reviewed and outcomes determined.

Results:  Twenty patients presented to our institution with SNMM over the study period. No cervical node or metastatic involvement was detected at presentation. The most common site of involvement was the nasal cavity (17/20). The majority of patients received initial surgery followed by radiotherapy (15/20). At the completion of treatment 14 patients had no disease evident. The median time to failure in these patients was 12 months. Of these patients 10 relapsed, including six who had metastatic failure only. Fifteen patients died due to disease. Median overall survival was 17 months, with a 2‐year overall survival of 23%. In univariate analysis, patients with advanced tumours (T3−4) had a 4.3 times greater risk of dying than patients with early tumours (T1−2).

Conclusions:  Patients with SNMM have poor outcomes with conventional therapy. Full staging prior to treatment is recommended. Aggressive treatment carrying significant morbidity is justified only for patients with early stage disease.
Current management of gall bladder perforations
Authors: Menakuru Somasekhar R. , Kaman Lileswar , Behera Arunanshu , Singh Rajinder , Katariya Rabindra Nath
Published: September 2004

Background:  Gall bladder perforation is a serious complication of acute cholecystitis. The purpose of the present study is to evaluate the presenting symptoms, diagnosis and management of patients with gall bladder perforations.

Methods:  A retrospective study was undertaken of 31 consecutive patients with gall bladder perforation in a single unit of a tertiary referral hospital, between January 1996 and December 2001.

Results:  The incidence of gall bladder perforation was 5.9% of all cases of acute cholecystitis. Associated comorbidity was quite common (58%). Ultrasound and computed tomography scans of the abdomen are sensitive investigations. Ultrasound guided percutaneous drainage helps in tiding over the emergency. The morbidity (35%) and mortality (9.6%) is considerable.

Conclusion:  The patterns of presentations, diagnosis and management of gall bladder perforation are changing. But there is scope for improvement.
Is bilateral duplex scanning necessary in patients with symptoms of deep venous thrombosis?
Authors: Lemech Lubomyr D. , Sandroussi Charbel , Makeham Virginia , Burnett Alison , Harris John P.
Published: September 2004

Background:  Venous duplex ultrasound scanning (VDUS) has been shown to be an accurate non‐invasive means to diagnose symptomatic deep venous thrombosis (DVT). The aim of our study was to determine whether bilateral VDUS is necessary in patients who present with symptoms of DVT.

Methods:  We retrospectively reviewed the results of bilateral lower extremity VDUS performed on 1029 inpatients at Royal Prince Alfred Hospital in the 24 months from 1 January 1998 to 31 December 1999.

Results:  Of the 1029 patients, 705 (69%) presented with unilateral symptoms and 324 (31%) with bilateral symptoms. The overall incidence of DVT was 168 (16% of 1029 patients). In 705 patients with unilateral symptoms the diagnosis of DVT was confirmed in 120 (17.0%), of whom 20 (16.7%) had unsuspected bilateral DVT. There were 12 patients (1.7% of the 705 patients) who had DVT in the asymptomatic limb, without DVT identified in the symptomatic limb. Overall there were 32 (5% of 705) patients with unilateral symptoms who had unsuspected DVT in the asymptomatic limb. Of the 20 patients with bilateral DVT, only one patient had more extensive DVT in the asymptomatic limb than in the symptomatic limb, that was therefore likely to alter treatment. Bilateral symptoms of DVT were present in 324 (31.5%) patients, 48 (14.8%) of whom were found to have DVT. Nineteen (39.6%) of these DVTs were bilateral.

Conclusion:  Overall the diagnostic yield of VDUS was low in this study, with an incidence of 16% of DVT detected in symptomatic patients. Techniques that improve the diagnostic yield of VDUS in symptomatic patients are required. A significant proportion (23%) of the DVT detected in this study were bilateral, and a small but significant proportion (10%) of DVT found in patients presenting with unilateral symptoms were only in the asymptomatic contralateral limb. Our study supports bilateral VDUS in symptomatic inpatients, as the detection of DVT in asymptomatic limbs aids future patient management if symptoms develop in the asymptomatic limb.
The demand for surgery: an analysis of referrals from Australian general practitioners
Authors: Gruen Russell L. , Knox Stephanie , Carson Phillip , O'Rourke Ian C. , Britt Helena , Bailie Ross S.
Published: September 2004

Background:  Optimal planning for surgical training and the surgical workforce requires knowledge of the need and demand for surgical care in the community. This has previously relied on indirect indicators, such as hospital throughput. We aimed to describe referrals from general practitioners (GPs) to surgeons in Australia using a classification of surgical disorders developed especially for primary care settings.

Methods:  Terms in the International Classification of Primary Care Version 2‐Plus were reclassified into categories delineated by specialist surgeons, resulting in the Surgical Nosology In Primary‐care Settings (SNIPS). Referrals to surgeons were analysed using data on 303 000 patient encounters by a random sample of 3030 GPs involved in the Bettering the Evaluation and Care of Health (BEACH) study.

Results:  Thirty‐two per cent (143 013) of all problems were classified as potential surgical problems, of which 9.5% (13 570) were referred to surgeons at an overall rate of 44.8 referrals per 1000 GP encounters. Patients with surgical problems were significantly older than the overall general practice patient population. Women and patients with health care cards were significantly less likely than men and patients without health care cards to be referred when a surgical problem was managed by the GP. Forty‐two per cent of all surgical referrals were accounted for by the following categories: skin lesions, skin infection/injury, upper gastrointestinal, breast lumps/cancer, spine, knee arthritis/pain, knee injury/instability, infective and non‐infective ear disorders. Many commonly referred problems are usually managed as outpatients.

Conclusions:  The data from this study may have application for surgical workforce planning and ensuring trainees receive adequate exposure to commonly referred conditions. The classification system (SNIPS) may be useful for future research concerning the interface between primary care and specialist surgical practice.
Diverticulectomy is inadequate treatment for short Meckel's diverticulum with heterotopic mucosa
Authors: Varcoe Ramon L. , Wong Shing W. , Taylor Claire F. , Newstead Graham L.
Published: September 2004

Background:  Meckel's diverticulum is a vestigial remnant of the vitellointestinal duct that may occasionally contain heterotopic gastric mucosa thought to arise from residual yolk sac cells. This may cause significant rectal bleeding, the source of which may be difficult to identify. The present paper addresses the question of whether the choice of resection technique should depend on the macroscopic appearance of the Meckel's diverticulum.

Methods:  A retrospective analysis of patients with resected Meckel's diverticulum at Prince of Wales and Sydney Children's Hospitals between 1992 and May 2003 was performed. The external appearance was expressed as a height‐to‐diameter ratio (HDR) and the presence or absence of macroscopic thickening was recorded. The morphology was then correlated with the presence and site of the heterotopic gastric mucosa (HGM).

Results:  Seventy‐seven patients were identified with an age range between 1 day and 92 years. Fifty‐seven (74%) of the patients were men. Presenting symptoms were gastrointestinal bleeding (11.7%), diverticulitis (15.6%), volvulus (2.6%), intussusception (10%) and umbilical fistula (7.8%). Fifty‐seven per cent of the resected Meckel's diverticulae were found incidentally. Eight patients underwent a technetium pertechnate nuclear Meckel's scan. The Meckel's scan detected only two of seven patients with HGM on pathological examination.

Twenty‐nine (38%) patients underwent diverticulectomy and 48 (62%) small bowel resection. Ectopic mucosa was found in 25 (32.5%) patients. Of the Meckel's diverticula that were defined as long (HDR >/=2.0) and containing HGM, five of five (100%) had the ectopic mucosa in the diverticular tip and body only. Of those that were short (HDR <2.0) there was a wide distribution of HGM sites with 12 (60%) involving the whole diverticulum including the base and eight (40%) involving the tip and body only. The presence or absence of macroscopic thickening was described in 18 resected Meckel's diverticula. Thirteen (72%) were described as thickened in the operation report and six of these 13 (46%) were found to have HGM. One of the seven (14%) Meckel's diverticulae with HGM was thought to be of normal appearance and was therefore undetected.

Conclusion:  Simple transverse resection is not recommended for the short Meckel's diverticulum. A HDR of 2.0 is recommended as the cut‐off when deciding on the most appropriate operation. The external appearance of the Meckel's diverticulum does not predict the presence of HGM and is therefore an unreliable indicator to aid resection decisions when presented with an incidental Meckel's diverticulum.
Randomized trial of a pain control infusion pump following inguinal hernia repair
Authors: Stewart Adam , Fan Michael Mar , Fong Michael James , Louie Adam , Lynch John Patrick , O'Shea Michael
Published: September 2004

Background:  Continuous ambulatory analgesia following various surgical procedures is gaining popularity. The purpose of the present paper is to evaluate this form of analgesia following open anterior inguinal hernia repair by way of a pain control infusion pump (PCIP).

Methods:  Forty‐eight consecutive patients scheduled for inguinal hernia repair were enrolled in a double‐blind, randomized, placebo‐controlled trial. Following the repair, a catheter was placed in the wound connected to an external PCIP, delivering either ropivacaine or normal saline at a fixed rate of 4 mL/ h. Regular 4‐hourly postoperative pain observations according to a Visual Analogue Score (VAS) and any rescue opioid requirements were recorded, at different levels of mobility.

Results:  Data analysis included 23 (ropivacaine) and 24 (saline) patients in each group, with one exclusion. There were no adverse effects of the PCIP in either group. Patients in the ropivacaine group (‘active pump’) had lower mean pain scores and less rescue analgesia compared to the saline group (‘placebo pump’). This clinical effect was found to be more striking at increased levels of mobility. Importantly, no patients in the ropivacaine group required any rescue analgesia after the first 4‐h block postoperatively.

Conclusion:  The PCIP provided safe and adequate analgesia following inguinal hernia repair. It provided effective analgesia especially when patients were mobilizing. This has implications for earlier discharge from hospital and associated cost‐savings.
The Surgical Acute Care Unit (SACU): effects on surgical workload and mortality
Authors: Bown Matthew J. , Norwood M. G. A. , Loftus I. M. , Spiers P. , Sayers R. D.
Published: September 2004

Background:  A surgical acute care unit (SACU) is designed to provide level 1 care for surgical patients. The aim of the present study was to audit the effects of the introduction of a SACU in a teaching hospital surgical department.

Methods:  A retrospective case‐note audit of all admissions to the newly established SACU over the first 6 months was performed. Expected mortality and morbidity was calculated using POSSUM (physiological and operative severity score for the enumeration of mortality and morbidity) scores. Critical care data for the same period and the 6 months prior to the SACU opening was examined to determine any effect on critical care workload.

Results:  The SACU admitted 131 patients during the audit period. There was no significant difference between predicted and observed mortality or morbidity. There was no effect on critical care length of stay after the SACU opened. Many patients who would have needed critical care beds before the SACU opened were admitted directly to the SACU after it opened.

Conclusions:  This audit demonstrates that the provision of a surgical acute care unit allows many patients who would normally need to be admitted to the critical care unit for postoperative care to be safely admitted to level 1 care beds.
Model for collecting colorectal cancer staging information in Western Australia
Authors: Boutard Padabphet , Platell Cameron , Threlfall Tim
Published: September 2004

Background:  There is recognition that to improve the management of patients with cancer we need to monitor outcomes, especially survival outcomes based on tumour stage. Unfortunately, there are few centres in Australia that can provide stage stratified survival information, despite the large investments that have been made in data collection. The aim of this study was to collect staging information for all colorectal cancers diagnosed in Western Australia over a 12‐month period. This information could then serve as a basis for more meaningful analysis.

Methods:  A project officer was appointed to coordinate a programme through the Western Australian Cancer Registry. A consensus was reached among pathologists on the standardized reporting of colorectal cancers to the registry. Clinicians were asked to provide, on pathology request forms, information on tumour location, the presence of metastatic disease (on X‐ray or at laparotomy), and type of surgery. Use was also made of existing hospital and unit based databases to acquire and crosscheck information.

Results:  Over a 12‐month study period, 1008 patients with colorectal cancers were notified to the Cancer Registry. Their mean age was 69.1 years (range 23−100 years), 56% were men and 44% women. The rectum was the most common site for disease location (32.5%). At cessation of the project, 743 patients (74%) were fully staged, with a further 221 patients (22%) having completed data on tumour depth of penetration and nodal status, but insufficient information on the presence of metastases. The stage distributions were: stage I − 20.5%; stage II − 29.9%; stage III − 26.2%; stage IV − 23.4%.

Conclusions:  It is feasible to collect staging information on colorectal cancers notified to a population based cancer registry. This information will be invaluable for stage stratified survival analysis and research.
Paediatric constipation for adult surgeons − article 2: new microscopic abnormalities and therapies
Authors: King Sebastian K. , Sutcliffe Jonathan R. , Hutson John M. , Southwell Bridget R.
Published: September 2004

Chronic constipation is a common condition in both adults and children. Children with chronic constipation frequently have symptoms that continue into adulthood. In the second part of the review we describe advances in the identification of abnormalities in the control of motility. The role of neurotransmitters in both paediatric and adult constipation is examined and the radical rethink of colonic dysmotility caused by the re‐emergence of interstitial cells of Cajal is discussed.

The recognition of chronic constipation as an heterogenous condition has led to the introduction of new therapies. Antegrade washouts through appendix stomas and an exciting new treatment with electrical interferential therapy may, in the future, result in a less invasive approach to the management of chronic constipation. An improved understanding of the assessment and management of chronic constipation in childhood is also likely to reduce the frequency and morbidity of chronic constipation in adults.
Kierkegaard on the Problems of Pure Irony
Authors: Frazier Brad
Published: September 2004

Søren Kierkegaard's thesis,The Concept of Irony, contains an interesting critique of pure irony. Kierkegaard's critique turns on two main claims: (a) pure irony is an incoherent and thus, unrealizable stance; (b) the pursuit of pure irony is morally enervating, psychologically destructive, and culminates in bondage to moods. In this essay, first I attempt to clarify Kierkegaard's understanding of pure irony as “infinite absolute negativity.” Then I set forth his multilayered critique of pure irony. Finally, I consider briefly a distinctly theological component in Kierkegaard's critique. I argue that this feature of Kierkegaard's account can and should be distinguished from the broadly ethical critique of pure irony that I sketch in the second section, even if these components of Kierkegaard's position are found together as a unified whole inThe Concept of Irony. My overall goal in this essay is to reveal the subtlety and plausibility of Kierkegaard's critique of pure irony. I also attempt to disclose the richness of the Hegelian account of ethical life to which Kierkegaard recurs in his thesis.