bluuebunny/crossref_metadata_2025 huggingface dataset:
Editorial
Authors: Jones Cliff
Published: April 2006

Formal Aspects of Computing

marks the end of the first year of our re-launched format. It has not been an easy year either for the editors or for the ever-patient staff at Springer-Verlag; but it has certainly been successful with first class papers being published soon after acceptance. As with most computing journals, refereeing poses a (potential) bottleneck to getting an author's ideas into print but even here our colleagues at Springer-Verlag have come up with an incentive scheme from which our future referees will benefit and hopefully speed the refereeing process to everyone's advantage.

Recently, most editions of the journal have been standard issues with a number of submitted papers. It has been our stated intention since the journal began to have special editions with whole editions on a single topic. We are currently planning such a special edition to mark Rod Burstall's retirement (in fact we have so many excellent papers that there will probably have to be a double edition).

This special issue collects a number of papers on X-machines edited by Mike Holcombe and myself. Mike has written a brief introduction and there follow five papers which have all been refereed by experts in the area (I took personal charge of having Mike's paper refereed).

The generalisation of the testing theory to non-deterministic stream X-machines is the focus of two articles. Non-determinism can be generalised in several ways. R. Hierons and M. Harman look at quasi-non-deterministic machines and describe an approach to dealing with the generation of test sets for such machines. F. Ipate and M. Holcombe look at another way to view non-determinism and also focus on test set generation, the issue of fairness becomes important if the strong claims about fault detection by the test sets are to be achieved. M. Gheorghe has investigated how a collection of formal grammars can be controlled by a type of generalised stream X-machine so that the languages generated by such a system of grammars can be determined. He has shown that relatively simple grammars can generate very complex languages using this approach.

T. Balanescu explores further generalisations of Stream X-machines and discusses how the design for test conditions can be adapted for a specific type of machine.

A. Cowling et al. look at communicating X-machine systems and consider how this approach can be used to model message passing using a simple communicating matrix metaphor. Models built this way can be used to generate, automatically, concurrent programs.

In a paper to appear in Volume 13, F. Ipate and M. Holcombe look at how the test theory can be adapted to apply to the communicating X-machines systems case.

Indeed, Volume 13 already looks to be an exciting mix of scientific contributions – we also expect to back on a more regular publication schedule by the end of 2001.
Connected components of sets of finite perimeter and applications to image processing
Authors: Ambrosio Luigi , Caselles Vicent , Masnou Simon , Morel Jean-Michel
Published: April 2006

This paper contains a systematic analysis of a natural measure theoretic notion of connectedness for sets of finite perimeter in

\mathbb R^N

, introduced by H. Federer in the more general framework of the theory of currents. We provide a new and simpler proof of the existence and uniqueness of the decomposition into the so-called

M

-connected components. Moreover, we study carefully the structure of the essential boundary of these components and give in particular a reconstruction formula of a set of finite perimeter from the family of the boundaries of its components. In the two dimensional case we show that this notion of connectedness is comparable with the topological one, modulo the choice of a suitable representative in the equivalence class. Our strong motivation for this study is a mathematical justification of all those operations in image processing that involve connectedness and boundaries. As an application, we use this weak notion of connectedness to provide a rigorous mathematical basis to a large class of denoising filters acting on connected components of level sets. We introduce a natural domain for these filters, the space

\mathrm{WBV}(\Omega)

of functions of weakly bounded variation in

\Omega

, and show that these filters are also well behaved in the classical Sobolev and BV spaces.
Perspective of practical biological control and population theories
Authors: Takagi Masami
Published: April 2006

We have not yet had sufficient theoretical explanation for successful biological control in which a key pest is controlled after an introduction of natural enemies. I compare here real features of successful biological control and theoretical host–parasitoid population models to reduce the gap between theory and practice. I first review the historical interaction between classical biological control projects and theoretical population models. Second, I consider the importance of host refuges in host–parasitoid population dynamics as concerns the mechanisms of low and stable host density. The importance of density–dependent parasitism through parasitoid reproduction in multivoltine host–parasitoid systems and supplemental generalist natural enemies are also discussed. Finally, I consider the difference in tactics for classical biological control and for augmentation of natural enemies in annual crop systems.
A genetic perspective on mating systems and sex ratios of parasitoid wasps
Authors: Antolin Michael F.
Published: April 2006

Parasitoid sex ratios are influenced by mating systems, whether complete inbreeding, partial inbreeding, complete inbreeding avoidance, or production of all‐male broods by unmated females. Population genetic theory demonstrates that inbreeding is possible in haplodiploids because the purging of deleterious and lethal mutations through haploid males reduces inbreeding depression. However, this purging does not act quickly for deleterious mutations or female‐limited traits (e.g., fecundity, host searching, sex ratio). The relationship between sex ratio, inbreeding, and inbreeding depression has not been explored in depth in parasitoids. The gregarious egg parasitoid, Trichogramma pretiosum Riley, collected from Riverside, CA (USA) produced a female‐biased sex ratio of 0.24 (proportion of males). Six generations of sibling mating in the laboratory uncovered considerable inbreeding depression (∼ 20%) in fecundity and sex ratio. A population genetic study (based upon allozymes) showed the population was inbred (Fit = 0.246), which corresponds to 56.6% sib‐mating. However, average relatedness among females emerging from the same host egg was only 0.646, which is less than expected (0.75) if ovipositing females mate randomly. This lower relatedness could arise from inbreeding avoidance, multiple mating by females, or superparasitism. A review of the literature in general shows relatively low inbreeding depression in haplodiploid species, but indicates that inbreeding depression can be as high as that found in Drosophila. Finally, mating systems and inbreeding depression are thought to evolve in concert (in plants), but similar dynamic models of the joint evolution of sex ratio, mating systems, and inbreeding depression have not been developed for parasitoid wasps.
Parasitoids as model organisms for ecologists
Authors: Godfray H. C. J. , Shimada Masakazu
Published: April 2006

This paper introduces the special issue of this journal, which is devoted to parasitoid ecology. We provide a brief review of the role that parasitoids have played in research in population, community, and behavioral ecology and speculate on their future importance to the subject.
Population fluctuations of the western tent caterpillar in southwestern British Columbia
Authors: Myers J. H.
Published: April 2006

Cyclic populations of western tent caterpillars fluctuate with a periodicity of 6–11 years in southwestern British Columbia, Canada. Typically, larval survival is high in early stages of the population increase, begins to decline midway through the increase phase, and is low through several generations of the population decline. Fecundity is generally high in increasing and in peak populations but is also reduced during the population decline. Poor survival and low fecundity for several generations cause the lag in recovery of populations that is necessary for cyclic dynamics. The dynamics of tent caterpillar populations vary among sites, which suggests a metapopulation structure; island populations in the rainshadow of Vancouver Island have more consistent cyclic dynamics than mainland populations in British Columbia. Sudden outbreaks of populations that last a single year suggest that dispersal from source to sink populations may occur late in the phase of population increase. Wellington earlier discussed qualitative variation among tent caterpillar individuals as an aspect of population fluctuations. The variation in caterpillar activity he observed was largely statistically nonsignificant. Recent observations show that the frequency of elongate tents as described by Wellington to characterize active caterpillars varies among populations but does not change in a consistent pattern with population density. The level of infection from nucleopolyhedrovirus (NPV) was high in some populations at peak density but was not associated with all population declines. Sublethal infection can reduce the fecundity of surviving moths, and there is a weak association between viral infection and egg mass size in field populations. The impact of weather in synchronizing or desynchronizing populations is a factor to be investigated further.
A review of factors affecting the population dynamics of jack pine budworm (Choristoneura pinus pinus Freeman)
Authors: McCullough D. G.
Published: April 2006

Jack pine budworm (Choristoneura pinus pinus Free.) (Lepidoptera: Tortricidae) is a native insect that periodically defoliates areas of jack pine (Pinus banksiana Lamb.) in the subboreal forests of North America east of the Rocky Mountains. Outbreaks of jack pine budworm generally occur at 6‐ to 12‐year intervals and collapse after 2–4 years. Periodicity of outbreaks varies and is associated with site‐related factors. Survival of early‐instar larvae during spring dispersal is tied to the abundance of pollen cones (microsporangiate strobili), which provide a refuge for larvae until current‐year needles expand. Jack pine trees that have been heavily defoliated produce few pollen cones in the following year, often resulting in high mortality of early‐stage larvae. A diverse guild of generalist parasitoids attack jack pine budworm, but only a few species account for most mortality in any area. Collapsing jack pine budworm populations are characterized by sharp declines in early instar survival, coupled with an increased rate of parasitism in the late larval and pupal stages. The reciprocal interaction between heavy defoliation and low pollen cone production, and increased parasitism of late‐stage larvae or pupae, are consistent with second‐order density dependence factors identified in analysis of a long‐term population data set. Since the 1950s, several jack pine budworm outbreaks have been roughly synchronous over a large geographic area, suggesting that Moran effect processes, as well as moth dispersal or other factors, may be involved in jack pine budworm dynamics. Although the short duration of outbreaks enables most trees to recover, over time dead trees and top‐killed trees accumulate in jack pine stands. Jack pine is well adapted to fire and when fires ignite, the accumulation of dead trees and woody debris often leads to intense wildfires followed by prolific regeneration. The three‐way interaction of jack pine, jack pine budworm, and fire ultimately serves to maintain vigorous stands and ensures continued hosts for jack pine budworm.
Egg weight variation in the butterfly Lycaena hippothoe: more small or fewer large eggs?
Authors: Fischer K. , Fiedler K.
Published: April 2006

Fecundity, egg weight, hatching success of eggs, and adult (offspring) weight were compared between three geographically separated populations (i.e., subspecies) of the butterfly Lycaena hippothoe. All these traits differed substantially between populations. Our data suggest that, on an interpopulational level, egg size is traded off against egg number, egg size varies independent of adult size, and there is (given equal egg size) a positive relationship between adult weight (body size) and fecundity. The significantly heavier eggs of the alpine population Lycaena hippothoe eurydame showed strikingly increased hatchability, especially at high temperatures, as compared to the other populations. However, the ultimate reasons favoring large egg size in the alpine population, whether as a result of direct selection on egg size, as a correlated response based on other selective pressures, or reflecting relaxed selection for maximized fecundity, remain to be discovered.
Two modes of host–enemy coevolution
Authors: Kniskern J. , Rausher M. D.
Published: April 2006

The process of coevolution between host and enemy has traditionally been viewed as an evolutionary arms race between resistance and counterresistance. The arms‐race metaphor of coevolution is widely accepted because it explains the evolution of many characters in species involved in host–enemy interactions. However, molecular work in plant–pathogen systems suggests a coevolutionary interplay between plant recognition of an attacking pathogen and pathogen evasion from recognition. We refer to this process as information coevolution, and contrast this with arms race coevolution to show that these two processes result in very different patterns of host resistance and enemy virulence at the population level. First, information coevolution results in a lower proportion of hosts that are susceptible to enemy attack within a population. Second, information coevolution produces a pattern of local maladaptation of enemy on host, a naturally occurring phenomenon that is difficult to explain under arms race coevolution. We then conduct a literature review to survey the empirical support for either mode of coevolution using the predicted patterns of host resistance and enemy virulence. Evidence supports both modes of coevolution in plant–enemy interactions, whereas no support is found for information coevolution in vertebrate–parasite and invertebrate–parasite systems.
Age distribution, growth, and lifetime copulation frequency of a freshwater snail, Clithon retropictus (Neritidae)
Authors: Shigemiya Yusuke , Kato Makoto
Published: April 2006

Clithon retropictus is a prosobranch snail species that reproduces in freshwater but spends its veliger period in the sea. The age distribution of this snail was investigated at three sites along Takase River in Japan by counting annual growth lines on their shells. Also, copulation performance was examined using sheaths of spermatophores stored in the bursa copulatrix of females. A mark–recapture census demonstrated that the number of growth lines was a good indicator of the age of a snail. The maximum number of growth lines was 20, suggesting that this species is one of the most long‐lived freshwater gastropods. All the populations were female biased; the growth rate was higher and the life span was longer in females. Because spermatophore sheaths received by a female remained in her bursa copulatrix without being digested or discharged, the number of spermatophores implies her lifetime number of copulations. The number ranged from 0 to 91 and increased with age. Comparisons of population demonstrated that the average age was older, and the lifetime copulation number was significantly lower, at the upper stream site. These findings suggest that upstream migration had occurred only when the snails were very young and that copulation had been suppressed at the upstream site. The observed shorter longevity in males and the female‐biased sex ratio are thought to be a result of the high cost paid by the male in multiple copulation.
Preference and performance linkage of a leaf‐mining moth on different Salicaceae species
Authors: Kagata Hideki , Ohgushi Takayuki
Published: April 2006

The relationship between oviposition prefer‐ence and offspring performance of a leaf‐mining moth (Paraleucoptera sinuella) on four Salicaceae species was investigated in 1997 and 1998. We observed the egg distribution pattern on different plant species in the field and carried out oviposition experiments in the laboratory to determine the preference of ovipositing females. We also examined larval survival, pupal mass, and developmental time to compare larval performance on each plant species. Egg density in the field differed significantly among plant species. However, egg density was not correlated exactly with demonstrated oviposition preference. No larvae could develop on two Salix species. This finding indicated that larval survival is the most critical index of larval performance. Larval performance on each plant species was correlated well with oviposition preference that was revealed by a no‐choice experiment in the laboratory. However, this correlation was not found in the field. These results indicate that the preference–performance linkage that was observed under laboratory conditions, was not always maintained in the field.
Influence of CO2 Pneumoperitoneum on Systemic and Peritoneal Cell‐mediated Immunity
Authors: Evrard Serge , Falkenrodt Annie , Park Adrian , Tassetti Vincent , Mutter Didier , Marescaux Jacques
Published: April 2006

Port site metastases could be due to mechanical reasons or impairment of host defenses. As it is known that carbon dioxide is toxic for lymphocytes in vitro we decided to investigate lymphocyte stress during laparoscopy. Blood samples and peritoneal fluids were obtained before and after pneumoperitoneum from 16 patients undergoing laparoscopic cholecystectomy. Lymphocyte subsets were determined by flow cytometry. Propidium iodide was used as a lymphocyte vitality test. Cytokines were measured by an ELISA system. Significant falls in the absolute lymphocyte count and T3 and T4 lymphocytes occurred on postoperative day 1 with a quick return to the preoperative value on day 2. T8, natural killer cells, T4/T8, and T4+/T8+ counts were stable. Interleukins 1β
and 6 and tumor necrosis factor‐α were depressed during the two postoperative days. Peritoneal lymphocytes were not destroyed by pneumoperitoneum as demonstrated by the propidium test, nor were they locally impaired by carbon dioxide. The circulating lymphocyte subpopulation decrease favors moderate, brief immunodepression. The origin of port site metastases is not immunologic depression but, rather, facilitated implantation of malignant cells by hyperpressure into raw tissues.
Technique of Video‐assisted Thoracoscopic Surgery for the Spine: New Approach
Authors: Huang Tsung‐Jen , Hsu Robert Wen‐Wei , Liu Hui‐Ping , Liao Yi‐Shyan , Shih Hsin‐Nung
Published: April 2006

Although video‐assisted thoracoscopy has only recently been applied to treat a variety of thoracic spine lesions, many problems and difficulties are encountered with this technique owing to limited trocar space and lack of suitable endoscopic instruments. Between November 1995 and March 1996, we practiced a new approach for video‐assisted thoracoscopic surgery, the “extended manipulating channel method,” for treating 18 patients with thoracic spinal lesions endoscopically. The thoracoscopic portals were made larger (usually 3–4 cm) and placed slightly more posterior than usual, which allows use of a combination of conventional spinal instruments and video‐assisted thoracoscopy to enter the chest cavity and be manipulated similar to that with techniques used for standard open surgical procedures. In our series the endoscopic spinal procedures included biopsy only (n= 1), thoracic discectomy (n= 1), multilevel anterior discectomy and fusion
(n= 1), corpectomy for decompression
(n= 4), decompressions and interbody fusions
(n= 10), and internal instrumentations
(n= 4). Throughout the operation only one trocar was used for introducing the thoracoscope. There were no intraoperative deaths, and no patients showed neurologic deterioration due to the procedures. We conclude that such a technique makes thoracoscopy‐assisted spinal surgery simpler and easier and has proved to be an effective, promising procedure. It does not appear to compromise the therapeutic goals set for the patients. The intraoperative vessel bleeding can be easily controlled, and the number of portals for the procedures can be reduced (on average, three portals are enough). Few endoscopic materials were used with our patients, and thus the total economic cost to the patients was reduced.
Economic Considerations for the Diagnosis and Therapy of Meniscal Lesions: Can Magnetic Resonance Imaging Help Reduce the Expense?
Authors: Weinstabl Reinhard , Muellner Thomas , Vécsei Vilmos , Kainberger F. , Kramer M.
Published: April 2006

With magnetic resonance imaging (MRI) the surgeon has such an effective diagnostic tool in the diagnosis of a meniscal lesion that the times of diagnostic arthroscopy should be in the past. A total of 823 patients with clinically diagnosed meniscal lesions were divided into two groups: group A, 143 patients underwent MRI and 75 of those arthroscopy; group B, 680 patients, 201 (30%) of whom were operated after being only clinically examined. MRI was done on a Siemens Medical System Magnetom 1.5 Tesla with a 256 × 256 matrix. Spinal echo and gradient echo images were performed with slices of 2 to 4 mm thickness. All meniscal tears were graded according to Reicher and Crues, respectively. Grades III and IV were judged to be positive for a meniscal lesion. Arthroscopy was carried out under general anesthesia and the usual technique. The MRI revealed the following results: Medial meniscus: accuracy 95%, positive predictive value (PPV) 92%, negative predictive value (NPV) 95%, sensitivity
98%, and specificity 82%; lateral meniscus: accuracy 97%, PPV 92%, NPV 98%, sensitivity 94%, and specificity 98%. The overall values for MRI of the medial and lateral menisci combined were: accuracy 96%, PPV 93%, NPV 98%, sensitivity 96%, and specificity 90%. The clinical examination often failed to diagnose a meniscal lesion:
accuracy 64%, PPV 59%, NPV 89%, sensitivity 96%, and specificity
33% for the medial meniscus. For the lateral meniscus the accuracy was
91%, PPV 61%, NPV 98%, sensitivity 89%, and specificity 91%. The overall values for the clinical investigation of the medial and lateral menisci combined were: accuracy 78%, PPV 60%, NPV 94%, sensitivity
93%, and specificity 62%. Investigation of all 201 patients operated from group B with MRI would have cost $160,800. The cost of 30% fewer arthroscopies would have been $562,800—in total $723,600. The operation of all 201 patients cost $804,000. Hence about $80,000 could have been saved by scanning all 201 patients and therefore reduce the rate of diagnostic arthroscopies.
Surgical Treatment for Splenic Hydatidosis
Authors: Safioleas Michael , Misiakos Evangelos , Manti Christine
Published: April 2006

Splenic involvement is rare in patients with hydatid disease even in endemic countries. The spleen is the third most commonly involved organ after the liver and the lung. In our series splenic echinococcosis represents 5.8% of abdominal hydatid disease. During the last 22 years, 14 patients were operated on for splenic hydatid cysts in our department. In 10 patients the spleen was the only location of hydatid disease; in 2 patients there was concomitant liver hydatid disease; one patient had disseminated intraabdominal disease; and one patient had a coexisting hydatid cyst in the quadriceps femoris muscle. Plain abdominal films, ultrasonography, and computed tomography scans were most useful for establishing the diagnosis. All patients underwent splenectomy alone or combined with management of cysts at other sites, except for two patients who underwent omentoplasty and one patient who underwent external drainage. One patient died during the early postoperative period (mortality rate 7%), and three patients had minor complications. Splenic hydatid disease should be included in the differential diagnosis when a splenic cyst is identified, especially in patients with a history of hydatid disease. Surgery remains the treatment of choice to avoid serious complications.
Single and Multiple Pyogenic Liver Abscesses: Clinical Course, Etiology, and Results of Treatment
Authors: Chou Fong‐Fu , Sheen‐Chen Shyr‐Ming , Chen Yaw‐Sen , Chen Mao‐Chan
Published: April 2006

A total of 483 patients with pyogenic liver abscess during the years 1986 to June 1995 were studied at Chang Gung Memorial Hospital in Kaohsiung: 343 were a single abscess and 140 were multiple abscesses. Males were predominantly affected by this disease. Abdominal pain was more frequent with the single abscess than with multiple abscesses, and jaundice was more frequent with multiple abscesses. Blood levels of alkaline phosphatase, bilirubin, and creatinine and the white blood cell count were significantly higher in patients with multiple abscesses than in those with a single abscess;
and the hemoglobin level was higher with single abscesses. The single abscess was usually larger than 5 cm, and the multiple abscesses were usually smaller than 5 cm. The single abscess was always located on the right side (72%) and the multiple abscesses always on the right or both sides. Single abscesses mainly had a cryptogenic origin (58.9%) and multiple abscesses a biliary origin (45.0%). Liver aspirates revealed Klebsiella pneumoniae, Escherichia coli, Streptococcus, Bacteroides,Enterococcus, among others. K. pneumoniae was more often found in a single abscess and E. coli more often in multiple abscesses. Percutaneous catheter drainage and aspiration comprised the main treatment initially, and the failure rate with multiple abscesses was higher than that with single abscesses. Surgical intervention should be considered for multiple abscesses because of the underlying disease. The overall mortality with multiple abscesses (22.1%) was higher than that with a single abscess (12.8%). Partial hepatectomy produced a low mortality rate for both single and multiple abscesses and should be considered in the presence of severe hepatic destruction by an abscess or a stone.
Pathologic and Clinical Aspects of Repair of Large Incisional Hernias after Implant of a Polytetrafluoroethylene Prosthesis
Authors: Bellón Juan M. , Contreras Luis A. , Sabater Cristina , Buján Julia
Published: April 2006

One of the alternatives for the repair of large incisional hernias is the use of a prosthetic material. The present retrospective study relates the experience acquired for treatment of large incisional hernias (hernial orifice > 10 cm) with ePTFE prostheses. Thirty‐eight massive incisional hernias were repaired using ePTFE 1 mm thick Soft Tissue Patches. Twenty‐four patients received a prosthetic patch of 10 × 15 cm, 13 a patch of 15 × 20 cm, and 1 a patch of 20 × 30 cm. In
30 cases the ePTFE was sutured to the recipient tissues with a double row of polypropylene stitches. For the first eight interventions the ePTFE was secured using a single row of polypropylene sutures. Pathologic studies of biopsies from patients who had undergone surgical reintervention at 40 days, 12 months, and 48 months, respectively, were done using light microscopy, scanning electron microscopy, and immunohistochemistry with human antimacrophage antibodies KP‐1. The follow‐up period for all patients was between 18 and 72 months. There was no perioperative mortality. No infection or rejection of prostheses was recorded. Seroma was present in four patients. Computed tomography was performed for evaluation purposes on 10 randomly selected patients
(mean postoperative delay 1–4 years) and showed the ePTFE encapsulated by newly formed tissue. One of the patients suffered from mechanical intestinal obstruction 40 days after implant and suffered a recurrence a year later. Three recurrences at the patch–recipient tissue interface where the ePTFE had been secured with a single row of polypropylene stitches were recorded after 8, 12, and 28 months. At 40 days good integration of the biomaterial was observed in the newly formed tissue. On both sides of the implant an accumulation of four to six strata of cells was appreciable. Some of them were labeled with KP‐1. Cell infiltration of the prosthesis was restricted to the most exterior third of the patch. There was no colonization at the patch–recipient tissue interface. At 12 and 28 months the cell barrier had almost disappeared. KP‐1‐labeled macrophages were scarce. Scanning electron microscopy revealed a well defined peritoneum. It may be concluded that: (1) a double suture row is recommended to secure the prosthesis; (2) ePTFE provides an adequate substrate for the formation of scar tissue; and (3) the macrophage response induced by the ePTFE decreases with time.
Efficacy of Fine‐Needle Aspiration Biopsy of Thyroid Nodules: Experience of a Mexican Institution
Authors: Lopez Luis H. , Canto Jorge A. , Herrera Miguel F. , Gamboa‐Dominguez Armando , Rivera Raul , Gonzalez Ofelia , Perez‐Enriquez Bernardo , Angeles‐Angeles Arturo , Letayf Victor , Rull Juan A.
Published: April 2006

In most centers only selected patients with high risk thyroid nodules undergo thyroid surgery, and fine‐needle aspiration biopsy (FNA) is used to select patients for surgical treatment. The aim of the present study was to evaluate the impact of FNA on the management of thyroid nodules at our institution. A total of 872 patients who underwent FNA over a period of 7 years were retrospectively analyzed. There were 66 men and 806 women with a mean age of 40 ± 15 years. Altogether 549 patients presented with a thyroid nodule and 323 with multinodular disease. The sensitivity and specificity of FNA were 90.0% and 99.8%, respectively. The positive and negative predictive values were 98% and 99%, respectively, and the accuracy was 99%. Our results are in agreement with those of other reports establishing that FNA of the thyroid is safe, reliable, and effective for differentiating benign from malignant nodules.
Perforated Peptic Ulcer: Long‐term Results after Simple Closure in the Elderly
Authors: Blomgren Lena G.M.
Published: April 2006

The relative incidence of peptic ulcer perforation in the elderly is rising, and the optimal surgical treatment has yet to be defined. To evaluate the long‐term result after simple closure a follow‐up study was initiated at a Swedish community hospital. During 1983–1992 a total of 151 patients were admitted with perforated peptic ulcer; 92 were elderly (i.e., 70 years or older), 63 of whom were operated with simple closure. Mortality at 30 days was
27% (17/63) and the total in‐hospital mortality 30% (19/63). After a mean follow‐up of 79 months, 14 of the 44 survivors are still alive. So far only three of the survivors have required additional hospitalization for complications of peptic ulcer disease. Because the rate of serious recurrences is low (14%, 6/44), it is concluded that simple closure is an adequate surgical treatment for peptic ulcer perforation in the elderly.
Increased Rate of Cholecystectomy after Introduction of Laparoscopic Cholecystectomy in Saudi Arabia
Authors: Al‐Mulhim Abdulmohsen A. , Al‐Ali Ahmad A. , Albar Adnan A. , Bahnassy Ahmad A. , Abdelhadi Maha , Wosornu Lade , Tamimi Tawfiq M.
Published: April 2006

A rapid increase in the rate of cholecystectomy was reported in eastern Saudi Arabia between 1977 and 1986. The aim of this study was to determine whether the rate of cholecystectomy in the same region was still rising after the introduction of laparoscopic cholecystectomy. From 1987 to 1995 a total of 24 hospitals in eastern Saudi Arabia were surveyed using a questionnaire. During the 9‐year study period, the rate of total cholecystectomy (open and laparoscopic) increased by 91%. Whereas the cholecystectomy rate decreased by 4% per annum from 1987 to 1990, it increased by 63.7% from 1991 to 1995 after the introduction of laparoscopic cholecystectomy. The increase in the rates of cholecystectomy was observed in all age groups and both sexes. Cholecystectomy was, however, most frequent among the age group 45–64 years followed by the age group 25–44 years. Young and female patients were more likely to undergo laparoscopic cholecystectomy than the open procedure. The rise in cholecystectomy rate deserves further evaluation with regard to the following: reasons for the increased rate of cholecystectomy, cholecystectomy‐related morbidity and mortality, and the total costs of cholecystectomy.
Prospective Evaluation of Selective Defunctioning Stoma for Low Anterior Resection with Total Mesorectal Excision
Authors: Poon Ronnie Tung‐Ping , Chu Kin‐Wah , Ho Judy Wai‐Chu , Chan Cheung‐Wah , Law Wai‐Lun , Wong John
Published: April 2006

Low anterior resection with total mesorectal excision for rectal carcinoma is associated with a high anastomotic leakage rate, and the effectiveness of a defunctioning stoma in preventing anastomotic leakage remains controversial. In this study a policy of selective defunctioning stoma for stapled colorectal anastomosis after low anterior resection with total mesorectal excision in 148 consecutive patients was evaluated prospectively. A defunctioning stoma was performed in 61 patients (41%) considered at high risk of anastomotic leakage. Clinical leakage occurred in 2 patients (3.3%) with a stoma and 11 patients (12.6%) without a stoma (p= 0.047). Among those without a stoma, the leakage rate among male patients (20.9%) was significantly higher than that for female patients (4.5%) (p= 0.022). Leakage subsided with conservative treatment in the two patients with a stoma, but seven patients without a stoma developed peritonitis requiring laparotomy. No deaths resulted from leakage, and there was one hospital death (0.6%) in the whole group. Median hospital stay was similar with and without a stoma (13.0 vs. 12.0 days) (p= 0.290). Closure of the stoma was associated with no mortality, a morbidity rate of 8.7%, and a median hospital stay of 6.0 days. In conclusion, a defunctioning stoma is effective in preventing clinical anastomotic leakage after low anterior resection with total mesorectal excision. The relatively high incidence of leakage in the low risk group indicates the difficulty of predicting anastomotic leakage and hence the need for more liberal use of a defunctioning stoma especially in male patients.
Laparoscopic Visualization of the Cystic Artery Anatomy
Authors: Balija Milivoj , Huis Marijan , Nikolić Vasilije , Štulhofer Mladen
Published: April 2006

Uncontrolled bleeding from the cystic artery and its branches is a serious problem that may increase the risk of intraoperative lesions to vital vascular and biliary structures. On laparoscopic visualization anatomic relations are seen differently than during conventional surgery, so proper knowledge of the hepatobiliary triangle anatomic structures under the conditions of laparoscopic visualization is required. We present an original classification of the anatomic variations of the cystic artery into two main groups based on our experience with 200 laparoscopic cholecystectomies, with due consideration of the known anatomicotopographic relations. Group I designates a cystic artery situated within the hepatobiliary triangle on laparoscopic visualization. This group included three types: (1) normally lying cystic artery, found in 147 (73.5%) patients; (2) most common cystic artery variation, manifesting as its doubling, present in 31 (15.5%) patients; and (3) the cystic artery originating from the aberrant right hepatic artery, observed in 11 (5.5%) patients. Group II designates a cystic artery that could not be found within the hepatobiliary triangle on laparoscopic dissection. This group included two types of variation: (1) cystic artery originating from the gastroduodenal artery, found in nine (4.5%) patients; and (2) cystic artery originating from the left hepatic artery, recorded in two (1%) patients.
Inflammatory Cecal Masses in Patients Presenting with Appendicitis
Authors: Poon Ronnie Tung‐Ping , Chu Kin‐Wah
Published: April 2006

An unexpected inflammatory cecal mass of uncertain etiology encountered during surgery for presumed appendicitis poses a dilemma to the surgeon when deciding the appropriate operative management. A retrospective study was performed to review the pathology and surgical management of this condition. Among 3224 patients who had emergency surgery for a diagnosis of acute appendicitis between January 1990 and December 1997, a group of 52 patients (1.6%) underwent either ileocecal resection or right hemicolectomy for an inflammatory cecal mass of uncertain etiology. The final pathologic diagnosis was cecal diverticulitis in 26 patients (50%), appendiceal phlegmon or abscess in 21 patients (40%), cecal carcinoma in 3 patients (6%), tuberculosis in 1 patient (2%) and schistosomiasis in another patient (2%). Altogether 34 patients underwent ileocecal resection, and 18 patients underwent right hemicolectomy, including the 3 patients with cecal carcinoma. Ileocecal resection was associated with a shorter mean operative time (144 vs. 201 minutes; p < 0.001), a lower morbidity rate (3% vs. 22%; p= 0.043), and a shortened mean postoperative hospital stay (6.8 vs. 11.2 days; p= 0.011) than right hemicolectomy. There was no mortality in either group. In conclusion, most inflammatory cecal masses are due to benign pathologies and could be managed safely and sufficiently with ileocecal resection. Careful intraoperative assessment including examination of the resected specimen is essential to exclude malignancy, which would require right hemicolectomy.
Prognostic Factors in 2230 Korean Colorectal Cancer Patients: Analysis of Consecutively Operated Cases
Authors: Park Young Jin , Park Kyu Joo , Park Jae‐Gahb , Lee Kuhn Uk , Choe Kuk Jin , Kim Jin‐Pok
Published: April 2006

To define the prognostic factors in Korean colorectal cancer patients, univariate and multivariate analysis were performed on data from 2230 consecutive patients who underwent resection for colorectal cancer at the Seoul National University Hospital. The prognostic variables used for the analysis included patient's age, gender, bowel obstruction, bleeding, symptom duration, preoperative leukocyte count, preoperative serum carcinoembryonic antigen (CEA) level, Dukes' stage, tumor location, tumor size, depth of bowel wall invasion, number of lymph node metastases, histologic differentiation, and gross morphology of tumor. The overall 5‐year survival rate was 62%. In the univariate analysis, all the factors except sex, symptom duration, and tumor size were associated with prognosis. Among the factors significant in the univariate analysis, Dukes' stage (p < 0.001), number of lymph node metastasis (p < 0.001), CEA level (p < 0.001), tumor location (p= 0.003), gross morphology of tumor (p= 0.017), and depth of bowel wall invasion (p= 0.031) were significant in the multivariate analysis. Several differences in prognostic factors between colon cancer and rectal cancer were observed. In the multivariate analysis, gross tumor morphology was significant only for colon cancer, and histologic differentiation was significant only for rectal cancer. Lymph node metastasis was an independent prognostic variable for both colon and rectal cancer, but its significance was more prominent for rectal cancer. Although Dukes' stage is the most reliable prognostic predictor, this study shows that other factors (preoperative CEA level, gross morphology of tumor, location of tumor, nodal status) also provide important information for the outcome of the patient.
Incidence of Malignant Melanoma in Auckland, New Zealand: Highest Rates in the World
Authors: Jones Wayne O. , Harman C. Richard , Ng Alexander K.T. , Shaw James H.F.
Published: April 2006

The calculation of incidence rates of melanoma in New Zealand has been hampered in the past by incomplete registration of cases. The aim of this study was to document the incidence of melanoma in the Auckland Caucasian population and to define the pathologic characteristics of these lesions. Data were collected for the Auckland region from the New Zealand Cancer Registry and the Auckland Melanoma Unit database for 1995 and combined with census statistics to give the crude and age‐standardized rates for invasive melanoma. The results were analyzed by gender, morphology, body site, and thickness. The crude annual incidence for invasive cutaneous malignant melanoma was 77.7/100,000. The age‐standardized annual rate was 56.2/100,000 with no statistically significant differences in the rates for males and females. The cumulative risk of developing melanoma over a lifetime, from age 0 to 74, was 5.7% overall. The age‐specific rates steadily increase with advancing age. The lesions were generally thin; 64% were less than 0.76 mm, and only 7% were thicker than 3.00 mm. In conclusion, the Caucasian population in the Auckland region has the highest incidence of melanoma in the world.
From Billroth to PCV: A Century of Gastric Surgery
Authors: Weil Peter H. , Buchberger Robert
Published: April 2006

The development of gastric surgery is one of the most fascinating chapters in surgical history. The first operations on the stomach were done during the second half of the nineteenth century; at first they were minor procedures but then gradually became more daring, major procedures—albeit with considerable mortality. The work of Theodor Billroth and his pupils ushered in the era of major resectional therapy, first for cancer and later also for ulcer disease. Complications due to the lack of understanding gastric physiology plagued the early days of ulcer surgery, and a variety of modifications tried to remedy these problems. Although the role of the vagus was known through Pavlov's studies, its practical application had to wait until well into the twentieth century. For several decades, resection and vagotomy, separately or combined, were practiced until more sophisticated types of vagotomy began to dominate and replace resection in the surgical treatment of ulcer disease. Resection remained the treatment for cancer. We thus see over a period of 100 years, owing to the increased understanding of physiologic factors, a gradual shift from major resections toward smaller, better directed procedures. The pioneering work of Billroth and his generation, however, must not be forgotten.
Symbolic Approaches to Probability Distributions in Process Algebra
Authors: Tofts C.
Published: April 2006

One of the major problems in modelling with process algebras is that of state explosion. With the addition of information describing duration, models become more exposed to growth in the size of the description of their behaviour. We describe a symbolic approach to the description of duration information within a probabilistic calculus that has two benefits: firstly we can describe behaviour without instantiating distributions; secondly we can control the growth in our system representation as a trade against model accuracy. We can compute upper bounds on performance without the inclusion of additional state information in our systems. A large example, from the discrete event simulation literature, is presented to demonstrate the effectiveness of the approach.
The evolution and diversification of Dicers in plants
Authors: Margis Rogerio , Fusaro Adriana F. , Smith Neil A. , Curtin Shaun J. , Watson John M. , Finnegan E. Jean , Waterhouse Peter M.
Published: April 2006

Most multicellular organisms regulate developmental transitions by microRNAs, which are generated by an enzyme, Dicer. Insects and fungi have two Dicer‐like genes, and many animals have only one, yet the plant, Arabidopsis, has four. Examining the poplar and rice genomes revealed that they contain five and six Dicer‐like genes, respectively. Analysis of these genes suggests that plants require a basic set of four Dicer types which were present before the divergence of mono‐ and dicotyledonous plants (∼200 million years ago), but after the divergence of plants from green algae. A fifth type of Dicer seems to have evolved in monocots.
The involvement of glycogen synthase kinase‐3 and protein phosphatase‐2A in lactacystin‐induced tau accumulation
Authors: Ren Qing-Guo , Liao Xiao-Mei , Wang Ze-Fen , Qu Zhong-Shen , Wang Jian-Zhi
Published: April 2006

Here, we demonstrated that lactacystin inhibited proteasome dose‐dependently in HEK293 cells stably expressing tau. Simultaneously, it induces accumulation of both non‐phosphorylated and hyperphosphorylated tau and decreases the binding of tau to the taxol‐stabilized microtubules. Lactacystin activates glycogen synthase kinsase‐3 (GSK‐3) and decreases the phosphorylation of GSK‐3 at serine‐9. LiCl inhibits GSK‐3 and thus reverses the lactacystin‐induced accumulation of the phosphorylated tau. Lactacystin also inhibits protein phosphase‐2A (PP‐2A) and it significantly increases the level of inhibitor 1 of PP‐2A. These results suggest that inhibition of proteasome by lactacystin induces tau accumulation and activation of GSK‐3 and inhibition of PP‐2A are involved.
Aquatic viruses: the emerging story
Authors: Raven John A.
Published: April 2006

It is likely that all living organisms can be infected by
one or more viruses. One of the latest higher taxa to be
converted from ‘no characterized viruses’ to ‘well characterized
viruses’ are the diatoms (Bacillariophyceae,
Heterokontophyta) with the recent publication of three
papers characterizing an ssRNA and a ssDNA virus from
two genera (Chaetoceros and Rhizosolenia) of marine planktonic
diatom (Nagasaki et al., 2004, 2005; Bettarel et al.,
2005). It would have been strange if viruses had not been
able to exploit the dominant, in terms of global primary
production, photosynthetic organisms in the ocean (assimilating
perhaps as much as 20 Pg inorganic C into organic
C per year), despite the less than completely convincing
arguments assembled by Raven & Waite (2004) as to
possible anti-viral defences unique to diatoms.
Are phytoplankton population density maxima predictable through analysis of host and viral genomic DNA content?
Authors: Brown Chris M. , Lawrence Janice E. , Campbell Douglas A.
Published: April 2006

Phytoplankton:virus interactions are important factors in aquatic nutrient cycling and community succession. The number of viral progeny resulting from an infection of a cell critically influences the propagation of infection and concomitantly the dynamics of phytoplankton populations. Host nucleotide content may be the resource limiting viral particle assembly. We present evidence for a strong linear correlation between measured viral burst sizes and viral burst sizes predicted from the host DNA content divided by the viral genome size, across a diversity of phytoplankton:viral pairs. An analysis of genome sizes therefore supports predictions of taxon-specific phytoplankton population density thresholds beyond which viral proliferation can trim populations or terminate phytoplankton blooms. We present corollaries showing that host:virus interactions may place evolutionary pressure towards genome reduction of both phytoplankton hosts and their viruses.
Flow cytometric analysis of virus-like particles and heterotrophic bacteria within coral-associated reef water
Authors: Patten Nicole L. , Seymour Justin R. , Mitchell James G.
Published: April 2006

Using flow cytometry, two distinct populations of virus-like particles (VLP) and heterotrophic bacteria were defined within the 12 cm water layer immediately overlying healthy, diseased and dead acroporid corals. Bacterial abundances were similar in overlying water for all coral types, however, VLP were 30% higher above diseased corals than healthy or dead corals. Mean virus to bacteria ratios (VBR) were up to 30% higher above diseased corals than above healthy or dead coral or in distant water. Concomitant with increasing VLP concentrations within 5 cm of coral surfaces, VBR distributions were generally highest above healthy and diseased coral and depressed above dead coral. These results suggest fundamental shifts in the VLP and bacterial community in water associated with diseased corals.