bluuebunny/crossref_metadata_2025 huggingface dataset:
Subduction‐flip during Iapetus Ocean closure and Baltica–Laurentia collision, Scandinavian Caledonides
Authors: Andréasson P. G. , Gee D. G. , Whitehouse M. J. , Schöberg H.
Published: December 2003

Evidence is presented here from the northern Scandinavian Caledonides for development of an extensional basin of Ashgill to Mid Llandovery age along the Baltoscandian margin immediately prior to Baltica–Laurentia collision. U/Pb multigrain and ion microprobe zircon dating of plagiogranites in the Halti Igneous Complex complement previous baddeleyite and zircon dating of a dolerite dyke, and zircon dating of anatectic granite; they demonstrate that this dunite, troctolite, gabbro, sheeted‐dyke complex ranges in age from c. 445 to 435 Ma. The dolerite dykes intruded and melted arkoses of inferred Neoproterozoic age. This evidence, taken together with previous documentation of ophiolites (Solund–Stavfjord), ophiolite‐like associations (Sulitjelma Igneous Complex) and several other mafic suites (e.g. Råna, Artfjället) of Ashgill to Llandovery age further south in the northern Scandinavian Caledonides, implies that Scandian collisional orogeny along this nearly 2000‐km‐long mountain belt was immediately preceeded by development of short‐lived marginal basins. The latter developed during the final closure of the Iapetus Ocean and are inferred to be of back‐arc origin, some (perhaps all) related to E‐dipping subduction. Collision of the continents at c. 435 Ma is inferred to have induced a flip in subduction polarity, leading to underthrusting of Laurentia by Baltica.
Heat flow and geodynamics in the Tyrrhenian Sea
Authors: Zito G. , Mongelli F. , De Lorenzo S. , Doglioni C.
Published: December 2003

The present heat flow in the southern Tyrrhenian Sea appears as a transient thermal wave that has migrated eastward in time. The higher heat flow in the south‐eastern side of the basin confirms the suggestion of an eastward‐migrating rift. Punctuation of the Tyrrhenian backarc extension in lithospheric boudins is accompanied by a concentrated increase in heat flow generated by asthenospheric intrusions and related magmatism progressively moving eastward. The migration of the asthenosphere in the same direction could explain these phenomena.
Calculating the long‐term displacement rates of a normal fault from the high‐resolution stratigraphic record (early Tethyan rifting, French Alps)
Authors: Chevalier F. , Guiraud M. , Garcia J.‐P. , Dommergues J.‐L. , Quesne D. , Allemand P. , Dumont T.
Published: December 2003

Displacement rates of normal faults deduced from stratigraphic data are often unreliable. Here we calculate the velocity of motion on a normal fault from the variations in accommodation potential on both sides of the fault within a high‐resolution time‐frame established by biostratigraphy and physical stratigraphy. Our example is the Ornon normal fault bounding the Early Jurassic Bourg‐d'Oisans Basin formed during Tethyan rifting. We show that motion on the fault was discontinuous when examined at high resolution and over a long time interval. During a first interval (Hettangian to Sinemurian Arietites bucklandi zone) a low rate of displacement (=202–423 m Myr−1) coeval with diffused extensional deformation throughout the sedimentary basin is observed. A second interval of localized deformation (Early Sinemurian Caenisites turneri zone) is characterized by higher rates of displacement on the fault (1846 m Myr−1). Our results concur with recent numerical models identifying the main stages of extensional deformation.
Lateral flow of African mantle below the nearby Tyrrhenian plate: geochemical evidence
Authors: Trua Teresa , Serri Giancarlo , Marani Michael P.
Published: December 2003

The Quaternary magmatism of the Southern Tyrrhenian basin represents a rare example of an active volcanic arc system where ocean island basalt (OIB) and island arc basalt (IAB) magmas coexist. Although there is general agreement on the importance of the Ionian oceanic lithosphere subduction in the genesis of the IAB magmatism, the tectono‐magmatic processes producing the coexisting OIB magmas are still poorly understood. Here we show that the geochemistry of the Quaternary Southern Tyrrhenian OIB‐type magmatism (i.e. Ustica island and Prometeo, a previously unknown submarine lava field) is very similar to that of OIB‐type volcanoes situated on the nearby African plate (i.e. Etna and Hyblean Plateau). Among the possible geodynamic scenarios proposed to explain the coexistence of OIB and IAB magmas in arc settings, we consider the development of a tear at the edge of the Ionian plate as the more likely mechanism to favour the flow of African asthenospheric mantle below the Tyrrhenian plate.
Low‐latitude and multiple geomagnetic reversals in the Neoproterozoic Puga cap carbonate, Amazon craton
Authors: Trindade R. I. F. , Font E. , D'Agrella‐Filho M. S. , Nogueira A. C. R. , Riccomini C.
Published: December 2003

Palaeomagnetic study of the carbonates that ubiquitously cap glacial deposits may constrain the latitudinal extent of Neoproterozoic glaciations and the duration of the greenhouse recovery. We present the first palaeomagnetic data on the Neoproterozoic cap carbonates covering the Amazon craton, which are folded along the Paraguay Belt. Samples collected at deformed beds along the Paraguay Belt present a single‐polarity secondary magnetization acquired by the end of the Brasiliano orogeny (540–520 Ma). In the cratonic area, a dual‐polarity component was isolated in dolostones at the base of the sequence. The presence of a stratabound reversal stratigraphy along with high unblocking temperatures strongly suggest that this magnetization is primary. This result implies a low palaeolatitude (22+6/−5°) for the Amazon block just after deposition of Puga diamictites. In addition, the presence of multiple reversals across the first 20 m of the cap carbonate sequence suggests that their sedimentation must have spanned hundreds of thousands of years at least.
Discovery of metamorphic diamonds in central China: an indication of a > 4000‐km‐long zone of deep subduction resulting from multiple continental collisions
Authors: Yang Jingsui , Xu Zhiqin , Dobrzhinetskaya Larissa F. , Green Harry W. , Pei Xianzhi , Shi Rendeng , Wu Cailai , Wooden Joseph L. , Zhang Jianxin , Wan Yusheng , Li Haibing
Published: December 2003

The Central Orogenic Belt (COB) of China is a major continental collision zone that contains extensive outcrops of deeply subducted and exhumed rocks at both the eastern and the western end of the belt. Here we report discovery of microdiamonds from both eclogites and felsic gneisses in the North Qinling zone in the central portion of the COB. This discovery demonstrates that the country rocks of continental affinity shared in the ultra‐high‐pressure metamorphic (UHPM) event and provides a bridge connecting the two previously recognized UHPM terranes, thereby establishing the existence of a UHPM belt extending more than 4000 km. Geochronological dating yields Early Palaeozoic ages in the west and Early Mesozoic ages in the east, recording two separate continental collisions overprinted within the COB. Occurrence of UHP metamorphism during recurrent continental collision here and in the Alps suggests that deep subduction of continental material during such collisions is probably common rather than exceptional, with significant implications for processes of plate tectonic reorganization and mantle mixing over time.
Physical models of magmatic intrusion during thrusting
Authors: Galland Olivier , De Bremond d'Ars Jean , Cobbold Peter R. , Hallot Erwan
Published: December 2003

To investigate how magma rises through the brittle upper crust in a context of compressional tectonics, we have performed experiments on scaled physical models. Powdered silica (having a cohesion of 300 Pa and an angle of internal friction of 38°) was used to represent brittle crust. A vegetable oil (with a Newtonian viscosity of 10−2 Pa·s at 50 °C) was used to represent magma. A moving piston shortened the models in a box, while oil was injected steadily at the base. On cooling to room temperature, the oil solidified. The resulting intrusions were thin sills, dykes and laccoliths. Their shapes and emplacement modes depended on the ratio R between rates of shortening and injection. From shapes and orientations of intrusions, we infer that hydraulic fracturing was one mechanism of emplacement. Unconsolidated intrusions strongly influenced thrust formation. On the basis of our experiments, we suggest that magmas in orogenic belts can rise along thrust faults.
Large‐scale slope failure involving Triassic and Middle Miocene salt and shale in the Gulf of Cádiz (Atlantic Iberian Margin)
Authors: Maestro Adolfo , Somoza Luis , Medialdea Teresa , Talbot Christopher J. , Lowrie Allen , Vázquez Juan T. , Díaz‐del‐Río V.
Published: December 2003

Sheets of salt and ductile shale advancing beyond the thrust front of the Gibraltar Arc (Iberian–Moroccan Atlantic continental margin) triggered downslope movements of huge allochthonous masses. These allochthons represent the Cádiz Nappe, which detached from the Gibraltar Arc along low‐angle normal faults and migrated downslope from the Iberian and Moroccan continental margins towards the Atlantic Ocean. Extensional tectonics initiated upslope salt withdrawal and downslope diapirism during large‐scale westward mass wasting from the shelf and upper slope. Low‐angle salt and shale detachments bound by lateral ramps link extensional structures in the shelf to folding, thrusting and sheets of salt and shale in the Gulf of Cádiz. From backstripping analyses carried out on the depocentres of the growth‐fault‐related basins on the shelf, we infer two episodes of rapid subsidence related to extensional collapses; these were from Late Tortonian to Late Messinian (200–400 m Myr−1) and from Early Pliocene to Late Pliocene (100–150 m Myr−1). The extensional events that induced salt movements also affected basement deformation and were, probably, associated with the westward advance of frontal thrusts of the Gibraltar Arc as a result of the convergence between Africa and Eurasia. The complexities of salt and/or shale tectonics in the Gulf of Cádiz result from a combination of the deformations seen at convergent and passive continental margins.
Laser microprobe 40Ar–39Ar analysis of pseudotachylyte and host‐rocks from the Tatra Mountains, Slovakia: evidence for late Palaeogene seismic/tectonic activity
Authors: Kohút Milan , Sherlock Sarah C.
Published: December 2003

Laserprobe 40Ar–39Ar data from fault‐related pseudotachylytes and granitic host‐rocks from the Tatra Mountains (Central Western Carpathians) resolve the controversy over the age of propagation of the sub‐Tatra detachment fault. This major structure has resulted in exhumation of crystalline basement to the north‐west, and subsidence and sediment deposition in the Palaeogene Central Carpathians Basin to the south‐east. Host‐rock biotite ages range from 331 Ma to 322 Ma, and pseudotachylyte spot ages range from 164 Ma to 28 Ma. Of these, the youngest group identify the maximum timing of the early stages of Tatra Mountains uplift, which continued in the Miocene (20–10 Ma) and culminated during the Quaternary. The wide‐ranging older ages are an artefact of an unsupported 40Ar component that is most likely a combination of both inherited and excess argon.
Reproductive cycles, larval mortality and population dynamics of a Late Cretaceous hippuritid association: a new approach to the biology of rudists based on quantitative three‐dimensional analysis
Authors: Götz Stefan , Stinnesbeck Wolfgang
Published: December 2003

Late Cretaceous rudist bivalves have been well studied in terms of taxonomy, stratigraphy and sedimentological context, but their palaeobiological aspects are poorly known and important questions remain unanswered such as those relating to reproduction and population dynamics. The analysis of a three‐dimensional high‐resolution dataset allowed a detailed evaluation of the ecology and population dynamics of the rudist Hippuritella vasseuri (Douvillé). Our research demonstrates that significant turnover of generations and a stable packing rate characterizes stable and healthy ecological conditions whereas decreasing packing rate, increasing larval mortality and the arrival of non‐hippuritid organisms characterize an association in decline. H. vasseuri reproduced in a cyclical (annual or biannual) pattern, as shown in vertical projection by five equidistant peaks of larval recruitment density within 60 mm of section. Survival chances of rudist larvae appear to have been unrelated to initial available space for settling but are favoured by subsequent increasing space and a low number of coeval competitors.
Lithology, landscape dissection and glaciation controls on catchment erosion as determined by cosmogenic nuclides in river sediment (the Wutach Gorge, Black Forest)
Authors: Morel Philippe , Von Blanckenburg Friedhelm , Schaller Mirjam , Kubik Peter W. , Hinderer Matthias
Published: December 2003

Cosmogenic nuclides, measured in quartz from recent river bedload, provide a novel tool to quantify catchment‐wide erosion rates at geologically meaningful time scales. Here we present an analysis of the geomorphological evolution of the 350 km2 Wutach catchment in the uplands of the south‐west German Black Forest. The robustness of the method is demonstrated by the fact that, although the area was affected by river capture at 18 kyr bp, the formed gorge is so narrow that spatially averaged erosion rates were not resolvably perturbed. However, because cosmogenic nuclides preserve an erosion memory of several thousand years, the only perturbation introduced was detected in the minor areas that have been subject to the last maximum glaciation. In unglaciated areas, an important relationship between lithology and erosion can by quantified: sandstone lithologies erode at 12–18 mm kyr−1, granite lithologies at 35–47 mm kyr−1 and limestone lithologies (as deduced from river load gauging) at 70–90 mm kyr−1.
Pyoderma gangrenosum associated with c‐ANCA (h‐lamp‐2)
Authors: Hoffman Mark D.
Published: December 2003

An 18‐year‐old African–American woman presented with a 3‐week history of painful ulcerations on her legs and trunk; she linked their onset to a fall and injury to the ankle. Well‐circumscribed hemorrhagic ulcerations with ragged borders were noted on the legs, thighs, hands, and breasts. A skin biopsy demonstrated abscess formation and focal dermal necrosis compatible with a diagnosis of pyoderma gangrenosum.

A laboratory work‐up disclosed the following: white blood cells (WBC) 9.5 cells/mm3, hemoglobin 10.5 g/dL; erythrocyte sedimentation rate (ESR) 33 mm/h (0–20); c‐ANCA (ANCA, antineutrophil cytoplasmic antibody) titer 1 : 320. Further testing revealed that the ANCA targeted both human lysosomal‐associated membrane protein‐2 (h‐lamp‐2) (> 200 EIA units [< 10]) and bactericidal/permeability increasing protein (BPI) (21 EIA units [< 10]), but neither proteinase‐3 (PR3) nor myeloperoxidase (MPO). The ANCA isotypes were both immunoglobulin G (IgG) and IgA. Urinalysis, antinuclear antibodies (ANA), antiphospholipid antibodies, serum protein immunofixation electrophoreses, and chest X‐ray were unremarkable.

Therapy with minocycline was initiated pending biopsy results, with a favorable but incomplete response. Oral prednisone was added at 0.6 mg/kg/day, resulting in closure of all lesions except those on the lower legs. These lesions resisted subsequent trials of topical nitroglycerine and clofazimine.

During questioning the patient acknowledged having three loose stools daily. She also reported an isolated episode of blood in her stool. A colonoscopy was performed, ulcerative colitis was diagnosed, and therapy with mesalamine was begun. At the family's request, the prednisone was stopped, notwithstanding the persistence of ankle ulcerations, and oral tacrolimus was administered at 0.2/mg/kg/day, leading to further improvement. Tacrolimus‐induced hypomagnesemia and paresthesias precluded the use of higher doses, and this agent was discontinued. Reinstitution of prednisone combined with dapsone ultimately led to complete healing.
Drugs and Wells' syndrome: a possible causal relationship?
Authors: Seçkin Deniz , Demirhan Beyhan
Published: December 2003

In April 1997, a 28‐year‐old woman presented with a 3‐day history of multiple papules and vesicles on the fingers and wrist of her right hand. She reported that she had been taking nonsteroidal anti‐inflammatory drugs containing tenoxicam and diclofenac sodium, and had no history of an insect bite. The medical history also included pruritic erythema on her trunk 1 month before her initial visit, and oral tenoxicam and diclofenac sodium treatment for ankle arthralgia 2 days before the skin lesions appeared. At that time, her dermatologist had told her that the skin lesions might be due to an insect bite and were secondarily infected. She took amoxicillin for the lesions, and during the following days developed bullous lesions on her hands and feet. The patient was diagnosed with ‘‘drug reaction’' at another hospital based on a histopathologic examination of the affected skin. Treatment with topical corticosteroids and oral antihistamines was ineffective.

Physical examination revealed a few crusted, erythematous, papular lesions on the dorsal aspects of the patient's feet, bullous lesions on her right wrist, and vesiculopapules on her fingers. She had no fever or other abnormal clinical findings.

Laboratory studies showed a white blood cell count of 6000/mL with 16.5% eosinophils. A bacterial culture of the content of one of the bullous lesions was negative. The results of stool tests for parasites and ova were negative. Clinical and laboratory findings were in line with the diagnosis of drug reaction. The patient was advised not to take nonsteroidal anti‐inflammatory drugs. The skin lesions resolved rapidly on treatment with wet compresses of Burow's solution and oral prednisolone (40 mg/day). The dose of prednisolone was gradually reduced, and was discontinued after 3 weeks. The patient was readmitted in July 1997 for an indurated, erythematous plaque on her left foot, a lesion that resembled cellulitis. Her history at that time included the initiation of amoxicillin treatment for a gingival abscess 2 days before the skin lesion appeared. The lesion regressed after amoxicillin was discontinued and the patient received an intramuscular injection of triamcinolone acetonide.

Several months later, in October 1997, she developed a similar cellulitis‐like lesion on her right ankle. This time there was no history of drug intake. We obtained a skin biopsy from the lesion, and histopathology revealed an intense eosinophilic infiltrate in the dermis and extending into the subcutaneous tissue. Flame figures were abundant (Fig. 1). We also observed edema and erythrocyte extravasation in the dermis. Based on these features and her history, a diagnosis of Wells' syndrome was made. The skin lesion resolved spontaneously, and she has experienced no lesion recurrence since.

A characteristic ‘‘flame figure’' (hematoxylin and eosin stain; original magnification, × 230)

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Neutrophilic eccrine hidradenitis unassociated with chemotherapy in a patient with acute myelogenous leukemia
Authors: Roustan Gaston , Salas Clara , Cabrera Rafael , Simón Angel
Published: December 2003

An 18‐year‐old female patient with acute myelogenous leukemia (AML) M2 was treated between March and June 1998 with idarubicin, cytarabine, busulfan and cyclophosphamide. In June 1998, an autologous hematopoietic peripheral blood stem cell transplant was performed. The patient was asymptomatic without treatment until January 1999, when a relapse of AML was observed.

In March 1999, when the patient was waiting for another allogenic hematopoietic transplantation, she presented to the Department of Dermatology, Clínica Universitaria Puerta de Hierro, Madrid, with an acute onset a few days previously of macular, slightly elevated, irregular patches with ill‐defined borders, confined to the anterior aspect of the trunk in a bilateral distribution, especially on both breasts (Fig. 1). The eruption was asymptomatic. The patient had not received any treatment of any kind in the preceding weeks before the appearance of the cutaneous lesions. She had received a blood transfusion 3 weeks previously. The patient also had a low‐grade fever (37.8 °C).

Irregular, ill‐defined erythematous plaque on the right breast

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Laboratory investigations showed pancytopenia and a slight elevation of hepatic enzymes. The rest of the parameters were within the normal range. Blood cultures were negative.

Histologic examination of a biopsy specimen taken from a cutaneous lesion showed a normal epidermis, a dermis with a sparse interstitial neutrophilic infiltrate, and a dense inflammatory infiltrate composed almost exclusively of neutrophils in and around the secretory portion of the eccrine glands (Fig. 2). The presence of necrotic epithelial cells was remarkable.

Dense neutrophilic infiltrate affecting the whole secretory portion of an eccrine gland

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Immunohistochemical techniques and special staining for bacteria or fungi did not provide any additional data.

The cutaneous eruption disappeared spontaneously in 2 weeks. An allogenic hematopoietic transplantation was performed. The patient died on day + 27 due to hepatic and pulmonary complications.
Laboratory and field evaluation of the pathogenicity of entomopathogenic nematodes to the red palm weevil, Rhynchophorus ferrugineus (Oliv.) (Col.: Curculionidae)
Authors: Abbas M. S. T. , Saleh M. M. E. , Akil A. M.
Published: December 2003

Ten Egyptian and imported entomopathogenic nematodes were evaluated for their pathogenicity to R. ferrugineus in both the laboratory and the field. In the laboratory, most nematodes were pathogenic to the pest larvae, pupae and adults. Larvae and adults were more susceptible to nematode infection (mostly 100 % mortality) than pupae enclosed in their cocoons. In the field however, the highest insect larval mortality was 66.67 % and most of nematodes failed in controlling the pest. Such failure could be due to hot weather, the tunnelling behaviour of the pest larvae and the too much sap in the infested sites in the trunks of palm trees.
Influence of mixed biocide GCSC‐BtA on the pupae and adult stages of Apanteles plutellae Kurd. (Hym., Braconidae) and its host.  Plutella xylostella (L.) (Lep., Plutellidae)
Authors: Şengonca Ç. , Liu B.
Published: December 2003

This paper deals with the influence of the mixed biocide GCSC‐BtA on the pupal and adult stages of Apanteles plutellae Kurd. (Hym., Braconidae) and its host, Plutella xylostella (L.) (Lep., Plutellidae). The results show that mortalities of the pupae of P. xylostella in the direct‐dip bioassay were 84.67 %, that of the adults in the residue bioassay at 1.2500 mg/ml concentration of GCSC‐BtA were 78.00 % which were significantly higher than the mortality values for the pupae with 54.62 % and adults with 48.13 % of A. plutellae. In contrast, cypermethrin showed extremely high toxicity to the pupae with 94.58 % and adults with 86.00 % mortality values of A. plutellae as compared to the low mortality values of 42.14 % for the pupae and 32.11 % for the adults of P. xylostella, with the same concentrations and bioassay methods. The LC50 values of GCSC‐BtA were 0.3402, 0.5516 and 1.2405, 1.9480 mg/ml for the pupae and adults of P. xylostella and A. plutellae, respectively, while the LC50 values for cypermethrin were 1.5652, 2.3471 and 0.1096, 0.1152 mg/ml, respectively. GCSC‐BtA was found more toxic to the pupae and adults of P. xylostella and safer to the pupae and adults of A. plutellae than cypermethrin. The possibilty of using GCSC‐BtA against P. xylostella under partial control by A. plutellae in vegetable fields is discussed.
Non‐target beetles (Coleoptera) in Trypodendron pheromone traps in Finland
Authors: Martikainen Petri
Published: December 2003

Non‐target beetles were surveyed in Trypodendron pheromone traps in 3 localities in Finland. Two window traps baited with Trypolure, containing lineatin dissolved in ethanol, and one control trap without attractant were used in each locality. A total of 1648 specimens belonging to 223 non‐target species were recorded. The species were divided into five ecological groups to be treated separately. Hylurgops palliatus and Hylastes cunicularius were abundant in baited traps, whereas other scolytids as a group did not show clear attraction. Other species living in recently dead trees, including bark‐ and wood‐boring species and associated species (predators, scavengers, fungivores, etc.), were clearly attracted by Trypolure. The most abundant ones were Hylecoetes flabellicornis, Thanasimus formicarius, Rhizophagus dispar, and Rhizophagus nitidulus. Although numerous in the samples, saproxylic species inhabiting more decayed wood and non‐saproxylic species did not seem to be attracted. Grouping of species into ecological groups was helpful in the search for attraction patterns among species that usually are scarce in pheromone traps.
Parasitoids of Saperda populnea (L.) (Coleoptera: Cerambycidae) on aspen (Populus tremula L.) in Bulgaria
Authors: Georgiev G.
Published: December 2003

The parasitoids of Saperda populnea (L.) (Col.: Cerambycidae) were studied in Bulgaria during the period 1997 – 2001. Galls with pest larvae were collected from young aspen trees at eight locations (Sofia, Kokaliane, Plana, Churek, Gorni Lom, Gintzi, Dolno Kamartzi and Klisura) and examined under laboratory conditions. Four species were reared from 1118 galls containing overwintering pest larvae: Iphiaulax impostor (Scop.) (Hym.: Braconidae), Dolichomitus populneus (Ratz.), Schreineria populnea (Gir.) (Hym.: Ichneumonidae) and Billaea irrorata (Meig.) (Dipt.: Tachinidae). All of the parasitoids were solitary. Schreineria populnea was found as a new parasitoid of the host in Bulgaria. B. irrorata emerged mainly from late‐stage S. populnea larvae; the remaining species from both early‐ and mid‐stage larvae. In the parasitoid complex of S. populnea, the most numerous were B. irrorata (59.8 %) and D. populneus (29.4 %). The percentage of host larval parasitism varied from 2.4 to 33.3, with an average of 9.7 %. B. irrorata was the most important in reducing the pest number. The average mortality of S. populnea caused by the tachinid was 5.8 %, and the highest mortality observed in individual study was 20.2 %.
Consumption rate and susceptibility to parasitic nematodes and chemical molluscicides of the pest slugsArion hortensiss. s. andA. distinctusJ.Iglesias, B.Speiser, Biological and chemical control of Arion hortensis s. l. slugs
Authors: Iglesias J. , Speiser B.
Published: December 2003

The species complexArion hortensiss. l. is among the most important pestiferous slugs in Europe. The speciesA. distinctusMabille andA. hortensisde Férussac have traditionally been grouped together under the denominationA. hortensis. Therefore, neither the feeding behaviour nor the susceptibility of the individual species to control measures are known. In the laboratory, mean daily consumption of lettuce was similar for both species. In a series of laboratory bioassays,A. distinctusandA. hortensiss. s. were exposed to the rhabditid nematodePhasmarhabditis hermaphroditaand to the chemical molluscicides metaldehyde and iron phosphate, and their feeding and health were measured. Both species showed a similar and low susceptibility to the biocontrol agentP. hermaphrodita. In field‐collected slugs, the incidence of nematodes was much lower inA. hortensiss. l. than inDeroceras reticulatumorArion lusitanicus.Metaldehyde and iron phosphate affected both slug species similarly. Therefore, our results do not indicate any major difference between the two slug species of agronomical relevance.
Failure of antiretroviral therapy to control Varicella zoster retinitis
Authors: Ramsay Andrew , Young Stephanie , Lightman Susan
Published: December 2003

The term necrotizing herpetic retinopathies encompasses a spectrum of diseases which includes cytomegalovirus (CMV) retinitis, acute retinal necrosis (ARN) and Varicella zoster retinitis (VZR). Varicella zoster retinitis is a rapidly progressive, necrotizing condition most commonly reported in patients with AIDS. A case of vitreous biopsy‐proven VZR is reported in a patient with AIDS that progressed despite immune recovery on highly active antiretroviral therapy (HAART) to a viral load < 50 copies/mL and a CD4 count of 230 cells/μL. This is in contrast to CMV retinitis in which maintenance therapy appears unnecessary once the CD4 count rises and the viral load falls on HAART. Patients with VZR and AIDS should therefore be monitored for reactivation of retinal disease despite HAART‐induced remission.
Left Atrial Radiofrequency Ablation During Cardiac Surgery in Patients with Atrial Fibrillation
Authors: MANTOVAN ROBERTO , RAVIELE ANTONIO , BUJA GIANFRANCO , BERTAGLIA EMANUELE , CESARI FRANCESCO , PEDROCCO ALESSANDRA , ZUSSA CLAUDIO , GEROSA GINO , VALFRÈ CARLO , STRITONI PAOLO ,   North‐eastern Italian Study on Radiofrequency Surgical Treatment of Atrial Fibrillation Investigators
Published: December 2003

Introduction: Intraoperative left atrial radiofrequency (RF) ablation recently has been suggested as an effective surgical treatment for atrial fibrillation (AF). The aim of this study was to verify the outcome of this technique in a controlled multicenter trial.

Methods and Results: One hundred three consecutive patients (39 men and 65 women; age 62 ± 11 years) affected by AF underwent cardiac surgery and RF ablation in the left atrium (RF group). The control group consisted of 27 patients (6 men and 21 women; age 64 ± 7 years) with AF who underwent cardiac surgery during the same period and refused RF ablation. Mitral valve disease was present in 89 (86%) and 25 (92%) patients, respectively (P = NS). RF endocardial ablation was performed in order to obtain isolation of both right and left pulmonary veins, a lesion connecting the previous lines, and a lesion connecting the line encircling the left veins to the mitral annulus. Upon discharge from the hospital, sinus rhythm was present in 65 patients (63%) versus 5 patients (18%) in the control group (P < 0.0001). Mean time of cardiopulmonary bypass was longer in the RF group (148 ± 50 min vs 117 ± 30 min, P = 0.013). The complication rate was similar in both groups, but RF ablation‐related complications occurred in 4 RF group patients (3.9%). After a mean follow‐up of 12.5 ± 5 months (range 4–24), 83 (81%) of 102 RF group patients were in stable sinus rhythm versus 3 (11%) of 27 in the control group (P < 0.0001). The success rate was similar among the four surgical centers. Atrial contraction was present in 66 (79.5%) of 83 patients in the RF group in sinus rhythm.

Conclusion: Endocardial RF left atrial compartmentalization during cardiac surgery is effective in restoring sinus rhythm in many patients. This technique is easy to perform and reproducible. Rare RF ablation‐related complications can occur. During follow‐up, sinus rhythm persistence is good, and biatrial contraction is preserved in most patients. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1289‐1295, December 2003)
Identification of Pulmonary Vein Potentials by Differential Site Atrial Pacing in Patients with Paroxysmal Atrial Fibrillation:
Authors: IWASA ATSUSHI , A. STOREY JAMES , TASHAKKOR BABAK , K. FELD GREGORY
Published: December 2003

Introduction: Pulmonary vein (PV) isolation may cure paroxysmal atrial fibrillation (PAF); however, identification of PV potentials may be difficult in sinus rhythm. Studies have suggested that atrial pacing may improve the identification of PV potentials.

Methods and Results: In 25 consecutive patients who underwent PV isolation for PAF, the results of pacing from the distal PV, distal and proximal coronary sinus, and high right atrium compared to sinus rhythm were analyzed to determine the most effective pacing site for identification of PV potentials. The percentage of confirmed PV potentials and the longest interval between atrial and PV potentials in each PV were compared during differential site pacing and sinus rhythm. PV potentials were confirmed in 63 (82%) of 77 PVs that could be mapped during the complete pacing protocol and during sinus rhythm. Distal PV pacing identified significantly more PV potentials (left upper pulmonary vein [LUPV] 100%, left lower pulmonary vein [LLPV] 84%, right upper pulmonary vein [RUPV] 80%, right lower pulmonary vein [RLPV] 53%) compared to other pacing sites and sinus rhythm. Among atrial pacing sites, those ipsilateral to the PV being mapped were the most effective for identifying PV potentials. The intervals between atrial and PV potentials were significantly longer during distal PV pacing than pacing at other sites (LUPV 81.6 ± 26.2 ms, LLPV 61.4 ± 26.1 ms, RUPV 59.7 ± 33.2 ms, RLPV 39.7 ± 26.7 ms).

Conclusion: (1) Distal PV pacing was most effective for identifying PV potentials. (2) The interval between atrial and PV potentials was longest during distal PV pacing. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1311‐1318, December 2003)
Total Atrioventricular Nodal Ablation Increases Atrial Fibrillation Burden in Patients with Paroxysmal Atrial Fibrillation Despite Continuation of Antiarrhythmic Drug Therapy
Authors: WILLEMS RIK , WYSE D. GEORGE , M. GILLIS ANNE ,   Atrial Pacing Periablation for Paroxysmal Atrial Fibrillation (PA) Study Investigators
Published: December 2003

Introduction: Total atrioventricular nodal (TAVN) ablation and pacing is an accepted and safe treatment for patients with drug‐refractory paroxysmal atrial fibrillation (AF). Many patients develop permanent AF within the first 6 months after TAVN ablation. This usually is ascribed to the cessation of antiarrhythmic drug therapy. We hypothesized that TAVN ablation itself creates an atrial substrate prone to AF.

Methods and Results: Patients participating in the Atrial Pacing Periablation for Paroxysmal Atrial Fibrillation (PA3) study who remained on stable antiarrhythmic drug therapy throughout follow‐up were included in this analysis. AF burden and the development of persistent AF in the preablation period were compared to two consecutive postablation periods. Echocardiographic changes also were evaluated. Twenty‐two patients remained on stable drug therapy (9 men and 13 women, age 59 ± 3 years). One patient developed persistent AF preablation compared to 10 postablation (P < 0.05). AF burden preablation was 3.0 ± 1.2 hours/day and increased to 10.4 ± 2.2 hours/day and 11.8 ± 2.3 hours/day in the two postablation follow‐up periods (P < 0.05). In patients with fractional shortening (FS) >30% prior to ablation, FS decreased significantly from 39.4%± 1.3% to 36.4%± 1.7% (P < 0.05). In contrast, in patients with a FS ≤30% prior to ablation, FS increased from 27%± 0.8% to 33.6 ± 1.7% (P < 0.05).

Conclusion: TAVN ablation increases AF burden and facilitates the development of persistent AF in patients with paroxysmal AF despite the continuation of antiarrhythmic drugs. Loss of AV and/or interventricular synchrony may lead to altered cardiac hemodynamics resulting in atrial stretch and increasing AF burden. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1296‐1301, December 2003)
Effects of Elevated Extracellular Potassium Ion Concentration on Anodal Excitation of Cardiac Tissue
Authors: ROTH BRADLEY J. , PATEL SALIL G.
Published: December 2003

Introduction: Anodal excitation of cardiac tissue occurs by two mechanisms: “make” and “break.” Anodal strength‐interval curves are divided into two sections, with break excitation occurring at short intervals and make at long intervals. Our goal is to determine how an elevated extracellular potassium ion concentration, [K]o, affects the mechanism of anodal excitation and influences the anodal strength‐interval curve.

Methods and Results: Computer simulations of unipolar stimulation were performed using the bidomain model, with membrane kinetics governed by the Luo‐Rudy model. The diastolic threshold for anodal stimulation first decreased and then increased with increasing [K]o, reaching a minimum value at [K]o= 12 mM. The mechanism for diastolic anodal excitation was make for all [K]o values except 13.3 mM, in which case it was break. For low [K]o (4 and 8 mM) the break section of the anodal strength‐interval contained a “dip,” but for high [K]o (12 and 13 mM), the dip disappeared.

Conclusion: High [K]o predisposes cardiac tissue to break excitation, which is thought to play an important role in reentry induction and defibrillation. Because fibrillation raises extracellular [K]o levels, break excitation may play a more important role in defibrillation than is suggested by simulations and experiments using normal [K]o values. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1351‐1355, December 2003)
Spontaneous Transition of 2:1 Atrioventricular Block to 1:1 Atrioventricular Conduction During Atrioventricular Nodal Reentrant Tachycardia:
Authors: LEE SHIH‐HUANG , TAI CHING‐TAI , CHIANG CHERN‐EN , YU WEN‐CHUNG , CHENG JUN‐JACK , DING YU‐AN , CHANG MAU‐SONG , CHEN SHIH‐ANN
Published: December 2003

Introduction: The incidence of spontaneous transition of 2:1 AV block to 1:1 AV conduction during AV nodal reentrant tachycardia has not been well reported. Among previous studies, controversy also existed about the site of the 2:1 AV block during AV nodal reentrant tachycardia.

Methods and Results: In patients with 2:1 AV block during AV nodal reentrant tachycardia, the incidence of spontaneous transition of 2:1 AV block to 1:1 AV conduction and change of electrophysiologic properties during spontaneous transition were analyzed. Among the 20 patients with 2:1 AV block during AV nodal reentrant tachycardia, a His‐bundle potential was absent in blocked beats during 2:1 AV block in 8 patients, and the maximal amplitude of the His‐bundle potential in the blocked beats was the same as that in the conducted beats in 4 patients and was significantly smaller than that in the conducted beats in 8 patients (0.49 ± 0.25 mV vs 0.16 ± 0.07 mV, P = 0.007). Spontaneous transition of 2:1 AV block to 1:1 AV conduction occurred in 15 (75%) of 20 patients with 2:1 AV block during AV nodal reentrant tachycardia. Spontaneous transition of 2:1 AV block to 1:1 AV conduction was associated with transient right and/or left bundle branch block. The 1:1 AV conduction with transient bundle branch block was associated with significant His‐ventricular (HV) interval prolongation (66 ± 19 ms) compared with 2:1 AV block (44 ± 6 ms, P < 0.01) and 1:1 AV conduction without bundle branch block (43 ± 6 ms, P < 0.01).

Conclusion: The 2:1 AV block during AV nodal reentrant tachycardia is functional; the level of block is demonstrated to be within or below the His bundle in a majority of patients with 2:1 AV block during AV nodal reentrant tachycardia, and a minority are possibly high in the junction between the AV node and His bundle. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1337‐1341, December 2003)
Development and Validation of an ECG Algorithm for Identifying the Optimal Ablation Site for Idiopathic Ventricular Outflow Tract Tachycardia
Authors: ITO SACHIKO , TADA HIROSHI , NAITO SHIGETO , KUROSAKI KENJI , UEDA MAREHIKO , HOSHIZAKI HIROSHI , MIYAMORI ISAMU , OSHIMA SHIGERU , TANIGUCHI KOICHI , NOGAMI AKIHIKO
Published: December 2003

Introduction: Idiopathic ventricular outflow tract tachycardia or premature ventricular contractions (OT‐VTs) can originate from several different sites in the outflow tract, including the left ventricular (LV) endocardium and epicardium. The aims of this study were (1) to develop an ECG algorithm to predict the origin of OT‐VT and (2) to test prospectively the accuracy of the algorithm.

Methods and Results: An algorithm was developed by correlating the 12‐lead ECG findings with the catheter ablation site in 80 patients with OT‐VT. The ECG characteristics of the QRS complex during the arrhythmia were analyzed. The catheter sites were verified by multiplane fluoroscopy. The outflow tract was classified into six subdivisions: right ventricular (RV) septum, RV free wall, RV near the His‐bundle region, LV endocardium, left sinus of Valsalva (LSV), and LV epicardium remote from the LSV. An OT‐VT originating from the LV epicardium remote from the LSV was defined as an OT‐VT in which the earliest ventricular activation was recorded at the LSV and radiofrequency ablation from the LSV failed. This algorithm subsequently was tested prospectively in 88 patients. Overall sensitivity was 88% and specificity was 95%. The positive and negative predictive values were 88% and 96%, respectively.

Conclusion: We describe a new ECG algorithm having a high sensitivity and specificity to identify the optimal ablation site for idiopathic ventricular outflow tachycardia or premature ventricular contractions. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1280‐1286, December 2003)
Atrioventricular Nodal Ablation and His‐Bundle Pacing:
Authors: OLIVIER N. BARI , EYSTER GEORGE E. , SANDERS ROB , CHENG JIE , BOHART GEORGE , GIRAND MIKE , BAILIE MARC
Published: December 2003

Introduction: QT interval prolongation following drug exposure is considered a marker for increased risk of drug‐induced arrhythmias. QT interval measurements are common components of the safety pharmacology assessment of new therapeutic compounds but are potentially confounded by concurrent changes in heart rate that also alter QT intervals. We describe an anesthetized canine model of AV dissociation with His‐bundle pacing that overcomes the confounding effects of a change in heart rate.

Methods and Results: Transvenous radiofrequency ablation of the AV node was performed in isoflurane‐anesthetized dogs and followed by open chest implantation of bipolar pacing electrodes in the vicinity of the His bundle. Pace rates were adjusted from 50 to 190 in steps of 20 beats/min, holding each step for 30 seconds. At each paced rate, QT intervals were measured manually to the nearest 1 ms to construct paced QT interval‐heart rate (QT‐HR) relationships. Paired QT‐HR relationships using identical ascending ramps of pace rates were compared to paired QT‐HR relationships with an ascending and descending pace ramp to evaluate short‐term reproducibility and hysteresis effects. For proof of concept, an additional QT‐HR relationship was constructed in three dogs after intravenous administration of a compound known to alter QT intervals: one dog received terfenadine (0.48 mg/kg bolus followed by 0.017 mg/kg/min infusion), one dog received quinidine (20 mg/kg), and the third dog received sotalol (1 and 3 mg/kg). Substantial interdog variation was found for QT‐HR, although short‐term reproducibility was high within one dog (average absolute difference for paired ascending ramps <5 ms). QT intervals measured during descending paced ramps were generally lower than the value for the corresponding paced rate on an ascending ramp. This hysteretic effect was small, averaging <7 ms over the entire ramp. All test compounds prolonged QT intervals and shifted the QT‐HR relationship upward. Maximal QT prolongation was 30 ms for terfenadine, 50 ms for quinidine, and 59 ms for sotalol.

Conclusion: AV nodal ablation and His‐bundle pacing provide a sensitive animal model to identify acute effects of test compounds on indices of myocardial repolarization such as the QT interval. The model is devoid of confounding effects of changing heart rates while enabling identification of effects of drugs over a wide range of controlled rates. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1356‐1360, December 2003)
Role of the Coronary Sinus in Maintenance of Atrial Fibrillation
Authors: ORAL HAKAN , OZAYDIN MEHMET , CHUGH AMAN , SCHARF CHRISTOPH , TADA HIROSHI , HALL BURR , CHEUNG PETER , PELOSI FRANK , KNIGHT BRADLEY P. , MORADY FRED
Published: December 2003

Introduction: Bursts of tachycardia arising in the pulmonary veins may play an important role in perpetuating atrial fibrillation (AF). However, the role of the coronary sinus (CS) in the perpetuation of AF has been unclear. The aim of this study was to determine whether the CS plays a role in perpetuation of AF.

Methods and Results: Pulmonary vein isolation was performed by segmental ostial ablation with radiofrequency energy in 22 consecutive patients with paroxysmal AF. Bipolar and unipolar electrograms recorded in the left atrium and CS were analyzed during atrial pacing from the mitral annulus and during AF. There was a mean of 2.5 ± 0.5 electrical connections between the CS and the left atrium. The electrical connections between the left atrium and CS were ablated with a mean of 6.2 ± 2.7 minutes of radiofrequency energy applied along the atrial side of the inferior mitral annulus. During AF, episodes of intermittent tachycardia alternated between the left atrium and the CS. Among the 22 patients, sustained AF was still inducible in 9 after pulmonary vein isolation. After electrical disconnection of the CS from the left atrium, sustained AF was inducible in only 3 of these 9 patients.

Conclusion: The CS may be a source of rapid repetitive electrical activity during AF. The lower probability of inducible sustained AF after electrical disconnection of the CS from the left atrium suggests that the CS may play a role in perpetuating AF. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1329‐1336, December 2003)
Para‐Hisian Entrainment: A Novel Pacing Maneuver to Differentiate Orthodromic Atrioventricular Reentrant Tachycardia from Atrioventricular Nodal Reentrant Tachycardia
Authors: Y. REDDY VIVEK , JONGNARANGSIN KRIT , M. ALBERT CHRISTINE , SABBOUR HANI , KEANE DAVID , MELA THEOFANIE , MCGOVERN BRIAN , N. RUSKIN JEREMY
Published: December 2003

Introduction: Para‐Hisian pacing during sinus rhythm can help to identify the presence of an accessory pathway (AP). In this maneuver, the retrograde activation time and pattern are compared during capture and loss‐of‐capture of the His bundle while pacing from a para‐Hisian position. However, identification of a retrograde AP does not necessitate that it is operative during the tachycardia of interest; conversely, slowly conducting or “distant” bypass tracts may not be identified. We evaluated the utility of entrainment or resetting of tachycardias from the para‐Hisian position to help distinguish atrioventricular nodal reentrant tachycardia (AVNRT) from orthodromic atrioventricular tachycardia (AVRT).

Methods and Results: Para‐Hisian entrainment/resetting was evaluated in 50 patients: 33 with AVNRT and 17 with AVRT. The maneuvers were performed using a standard quadripolar catheter placed at the His position: low output for right ventricular (RV) capture and high output for both RV and His capture. The retrograde atrial activation sequence, SA interval (interval from stimulus to earliest retrograde atrial activation), and “local” VA interval (interval between the ventricular and atrial electrograms at the site of earliest retrograde atrial activation) were compared between His and His/RV capture. The ΔSA was >40 ms in patients with AVNRT and was <40 ms in all but one patient with AVRT. In concert with the ΔSA interval, the ΔVA interval was able to fully define the mechanism of the tachycardia in all patients studied.

Conclusion: Para‐Hisian entrainment/resetting can determine the course of retrograde conduction operative during narrow complex tachycardias. It is a useful diagnostic maneuver in differentiating AVNRT and orthodromic AVRT. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1321‐1328, December 2003)