bluuebunny/crossref_metadata_2025 huggingface dataset:
Transition from non-motile behaviour to directed migration during early PGC development in zebrafish
Authors: Blaser Heiko , Eisenbeiss Silke , Neumann Marc , Reichman-Fried Michal , Thisse Bernard , Thisse Christine , Raz Erez
Published: August 2005

The migration of zebrafish primordial germ cells (PGCs) is directed by SDF-1a and serves as a model for long-range chemokine-guided cell migration. Whereas the development and migration of zebrafish PGCs have been studied in great detail starting at mid-gastrulation stages when the cells exhibit guided active migration [7-8 hours post fertilization (hpf)], earlier stages have not yet been examined. Here we show that the PGCs acquire competence to respond to the chemokine following discrete maturation steps. Using the promoter of the novel gene askopos and RNA elements of nanos1 to drive GFP expression in PGCs, we found that immediately after their specification (about 3 hpf) PGCs exhibit simple cell shape. This stage is followed by a phase at which the cells assume complex morphology yet they neither change their position nor do they respond to SDF-1a. During the third phase, a transition into a `migratory stage' occurs as PGCs become responsive to directional cues provided by somatic cells secreting the chemokine SDF-1a. This transition depends on zygotic transcription and on the function of the RNA-binding protein Dead end and is correlated with down regulation of the cell adhesion molecule E-cadherin. These distinctive morphological and molecular alterations could represent a general occurrence in similar processes critical for development and disease.
Import of rat mitochondrial citrate carrier (CIC) at increasing salt concentrations promotes presequence binding to import receptor Tom20 and inhibits membrane translocation
Authors: Zara Vincenzo , Ferramosca Alessandra , Papatheodorou Panagiotis , Palmieri Ferdinando , Rassow Joachim
Published: August 2005

Mitochondria contain a family of related carrier proteins that mediate transport of metabolites across the mitochondrial inner membrane. All members of this family are synthesized in the cytosol. We characterized the interactions of newly synthesized rat citrate carrier (CIC) precursor protein (pCIC) with the components of the mitochondrial protein import machinery. pCIC contains both a positively charged presequence of 13 amino acids and internal targeting sequences. We found that the pCIC presequence does not interfere with the import pathway and merely acts as an internal chaperone in the cytosol. Under conditions of increased ionic strength, the pCIC presequence binds to the import receptor Tom20 and accumulates at the mitochondrial surface, thereby delaying pCIC translocation across the mitochondrial outer membrane. Similarly, the presequence of the bovine phosphate carrier (PiC) precursor protein (pPiC) is arrested at the mitochondrial surface when salt concentrations are elevated. We conclude that presequences can only act as mediators of mitochondrial protein import if they allow rapid release from import receptor sites. Release from receptors sites may be rate-limiting in translocation.
PATJ connects and stabilizes apical and lateral components of tight junctions in human intestinal cells
Authors: Michel Didier , Arsanto Jean-Pierre , Massey-Harroche Dominique , Béclin Christophe , Wijnholds Jan , Le Bivic André
Published: August 2005

The Crumbs complex that also contains the cortical proteins Stardust and DPATJ (a homologue of PATJ), is crucial for the building of epithelial monolayers in Drosophila. Although loss of function of the Crumbs or Stardust genes prevents the stabilization of a belt of adherens junctions at the apico-lateral border of the cells, no phenotype has been described for the Dpatj gene and its role in epithelial morphogenesis and polarity remains unknown. We have produced downregulated PATJ stable lines of Caco2 to clarify its role in epithelial morphogenesis. In PATJ knockdown cells, Pals1 (a Stardust homologue) is no longer associated with tight junctions whereas Crumbs3 (Crb3) is accumulated into a compartment spatially close to the apical membrane and related to early endosomes. Furthermore, occludin and ZO-3, two proteins of tight junctions are mislocalized on the lateral membrane indicating that PATJ plays a novel role in the building of tight junctions by providing a link between their lateral and apical components. Thus, PATJ stabilizes the Crb3 complex and regulates the spatial concentration of several components at the border between the apical and lateral domains.
Active relocation of chromatin and endoplasmic reticulum into blebs in late apoptotic cells
Authors: Lane Jon D. , Allan Victoria J. , Woodman Philip G.
Published: August 2005

Plasma membrane blebbing is a defining characteristic of apoptosis, but its significance is not understood. Using live-cell imaging we have identified two phases of apoptotic blebbing. The early phase is restricted to adherent cells, and is prevented by the Rho-activated kinase inhibitor Y27632. The late phase is partially resistant to Y27632, and generates morphologically distinct membrane protrusions that are likely precursors to apoptotic bodies. Late blebbing is observed in all apoptotic cells tested. It occurs at a fixed period before phosphatidyl serine exposure, indicating that it is a universal and important feature of apoptosis. Late blebs contain a cortical layer of endoplasmic reticulum that often surrounds condensed chromatin, while other organelles are excluded. The appearance in some apoptotic cells of partially formed sheets of endoplasmic reticulum suggest that these cortical layers are newly formed by the remodelling of the endoplasmic reticulum of interphase cells. Formation of endoplasmic reticulum and chromatin-containing blebs requires both actin and microtubules, and is prevented by the caspase-6 inhibitor zVEID.fmk.
Regulating cell migration: calpains make the cut
Authors: Franco Santos J. , Huttenlocher Anna
Published: August 2005

The calpain family of proteases has been implicated in cellular processes such as apoptosis, proliferation and cell migration. Calpains are involved in several key aspects of migration, including: adhesion and spreading; detachment of the rear; integrin- and growth-factor-mediated signaling; and membrane protrusion. Our understanding of how calpains are activated and regulated during cell migration has increased as studies have identified roles for calcium and phospholipid binding, autolysis, phosphorylation and inhibition by calpastatin in the modulation of calpain activity. Knockout and knockdown approaches have also contributed significantly to our knowledge of calpain biology, particularly with respect to the specific functions of different calpain isoforms. The mechanisms by which calpain-mediated proteolysis of individual substrates contributes to cell motility have begun to be addressed, and these efforts have revealed roles for proteolysis of specific substrates in integrin activation, adhesion complex turnover and membrane protrusion dynamics. Understanding these mechanisms should provide avenues for novel therapeutic strategies to treat pathological processes such as tumor metastasis and chronic inflammatory disease.
Surface Modification of Photoluminescent CdS Nanocrystals Inducing Spontaneous Phase Transfer Reaction
Authors: Kuwabata Susumu , Sato Keiichi , Hattori Shinya , Chiba Taeko , Ueda-Sarson Keiko , Tachibana Yasuhiro , Torimoto Tsukasa
Published: August 2005

A facile one-step method to modify the surface of luminescent CdS nanocrystals by alkylamines, without their luminescence intensity loss, was established. The interfacial modification inducing spontaneous transfer of the CdS from an aqueous to a non-polar organic phase was found to be controlled simply by choosing the alkyl group of the amine. Analysis of the absorption and emission spectra revealed the phase transfer yield of ca. 100%.
The First RuIIPdII2S3 Metallochelate Ring Formed on a [Ru(bpy)2]2+ Core
Authors: Yoshimura Takashi , Shinohara Atsushi , Hirotsu Masakazu , Konno Takumi
Published: August 2005

The 1:2 reaction of [RuCl2(bpy)2] (bpy = 2,2′-bipyridine) with [Pd(aet)2] (aet = 2-aminoethanethiolate) led to the formation of [Ru(bpy)2{Pd2(aet)3}{Pd(aet)2}]3+ ([1]3+), which was converted into [Ru(bpy)2{Pd2(aet)3}{Pd(aet)(2-aminoethanesulfenato)}]3+ ([1′]3+) and [Ru(bpy)2{Pd2(aet)3Cl}]2+ ([2]2+) having a six-membered RuPd2S3 metallochelate ring.
Bacterial contaminants and antibiotic prophylaxis in total hip arthroplasty
Authors: Al-Maiyah M. , Hill D. , Bajwa A. , Slater S. , Patil P. , Port A. , Gregg P. J.
Published: August 2005

We have investigated the contaminating bacteria in primary hip arthroplasty and their sensitivity to the prophylactic antibiotics currently in use. Impressions (627) of the gloved hands of the surgical team in 50 total hip arthroplasties were obtained on blood agar. The gloves were changed after draping, at intervals of 20 minutes thereafter, and before using cement. Changes were also undertaken whenever a visible puncture was detected. The culture plates were incubated at 37°C for 48 hours. Isolates were identified and tested for sensitivity to flucloxacillin, which is a recognised indicator of sensitivity to cefuroxime. They were also tested against other agents depending upon their appearance on Gram staining.

We found contamination in 57 (9%) impressions and 106 bacterial isolates. Coagulase-negative staphylococci were seen most frequently (68.9%), but we also isolated Micrococcus (12.3%), diphtheroids (9.4%), Staphylococcus aureus (6.6%) and Escherichia coli (0.9%). Of the coagulase-negative staphylococci, only 52.1% were sensitive to flucloxacillin and therefore to cefuroxime. We believe that it is now appropriate to review the relevance of prophylaxis with cefuroxime and to consider the use of other agents.
Impact loading of articular cartilage during transplantation of osteochondral autograft
Authors: Whiteside R. A. , Jakob R. P. , Wyss U. P. , Mainil-Varlet P.
Published: August 2005

Surgical reconstruction of articular surfaces by transplantation of osteochondral autografts has shown considerable promise in the treatment of focal articular lesions. During mosaicplasty, each cylindrical osteochondral graft is centred over the recipient hole and delivered by impacting the articular surface. Impact loading of articular cartilage has been associated with structural damage, loss of the viability of chondrocytes and subsequent degeneration of the articular cartilage. We have examined the relationship between single-impact loading and chondrocyte death for the specific confined-compression boundary conditions of mosaicplasty and the effect of repetitive impact loading which occurs during implantation of the graft on the resulting viability of the chondrocytes.

Fresh bovine and porcine femoral condyles were used in this experiment. The percentage of chondrocyte death was found to vary logarithmically with single-impact energy and was predicted more strongly by the mean force of the impact rather than by the number of impacts required during placement of the graft. The significance of these results in regard to the surgical technique and design features of instruments for osteochondral transplantation is discussed.
Suturing of lacerations of skeletal muscle
Authors: Kragh J. F. , Svoboda S. J. , Wenke J. C. , Ward J. A. , Walters T. J.
Published: August 2005

Our aim was to compare the biomechanical properties of suturing methods to determine a better method for the repair of lacerated skeletal muscle.

We tested Kessler stitches and the combination of Mason-Allen and perimeter stitches. Individual stitches were placed in the muscle belly of quadriceps femoris from a pig cadaver and were tensioned mechanically. The maximum loads and strains were measured and failure modes recorded. The mean load and strain for the Kessler stitches were significantly less than those for combination stitches. All five Kessler stitches tore out longitudinally from the muscle. All five combination stitches did not fail but successfully elongated.

Our study has shown that the better method of repair for suturing muscle is the use of combination stitches.
Is there a place for shelf acetabuloplasty in the management of adult acetabular dysplasia?
Authors: Fawzy E. , Mandellos G. , De Steiger R. , McLardy-Smith P. , Benson M. K. D. , Murray D.
Published: August 2005

We followed up 76 consecutive hips with symptomatic acetabular dysplasia treated by acetabular shelf augmentation for a mean period of 11 years. Survival analysis using conversion to hip replacement as an end-point was 86% at five years and 46% at ten years. Forty-four hips with slight or no narrowing of the joint space pre-operatively had a survival of 97% at five and 75% at ten years. This was significantly higher (p = 0.0007) than that of the 32 hips with moderate or severe narrowing of the joint-space, which was 76% at five and 22% at ten years. There was no significant relationship between survival and age (p = 0.37) or the pre- and post-operative centre-edge (p = 0.39) and acetabular angles (p = 0.85).

Shelf acetabuloplasty is a reliable, safe procedure offering medium-term symptomatic relief for adults with acetabular dysplasia. The best results were achieved in patients with mild and moderate dysplasia of the hip with little arthritis.
The effect of recombinant human osteogenic protein-1 on allograft incorporation
Authors: Lietman S. A. , Inoue N. , Rafiee B. , Deitz L. W. , Chao E. Y. S.
Published: August 2005

We used a canine intercalary bone defect model to determine the effects of recombinant human osteogenic protein 1 (rhOP-1) on allograft incorporation. The allograft was treated with an implant made up of rhOP-1 and type I collagen or with type I collagen alone.

Radiographic analysis showed an increased volume of periosteal callus in both test groups compared with the control group at weeks 4, 6, 8 and 10. Mechanical testing after 12 weeks revealed increased maximal torque and stiffness in the rhOP-1 treated groups compared with the control group.

These results indicate a benefit from the use of an rhOP-1 implant in the healing of bone allografts. The effect was independent of the position of the implant. There may be a beneficial clinical application for this treatment.
Cementless total hip arthroplasty using a threaded cup and a rectangular tapered stem
Authors: Pospischill M. , Knahr K.
Published: August 2005

We carried out a clinical and radiological review of 103 cementless primary hip arthroplasties with a tapered rectangular grit-blasted titanium press-fit femoral component and a threaded conical titanium acetabular component at a mean follow-up of 14.4 years (10.2 to 17.1).

The mean Harris hip score at the last follow-up was 89.2 (32 to 100). No early loosening and no fracture of the implant were found. One patient needed revision surgery because of a late deep infection. In 11 hips (10.7%), the reason for revision was progressive wear of the polyethylene liner. Exchange of the acetabular component because of aseptic loosening without detectable liner wear was carried out in three hips (2.9%).

After 15 years the survivorship with aseptic loosening as the definition for failure was 95.6% for the acetabular component and 100% for the femoral component.
Displacement of the common peroneal nerve in posterolateral corner injuries of the knee
Authors: Bottomley N. , Williams A. , Birch R. , Noorani A. , Lewis A. , Lavelle J.
Published: August 2005

We reviewed the relationship between the pattern of damage to the posterolateral corner of the knee and the position of the common peroneal nerve in 54 consecutive patients with posterolateral corner disruption requiring surgery. We found that 16 of the 18 patients with biceps avulsions or avulsion-fracture of the fibular head had a displaced common peroneal nerve. The nerve was pulled anteriorly with the biceps tendon. None of the 34 proximal injuries resulted in an abnormal nerve position.

Whenever bone or soft-tissue avulsion from the fibular head is suspected, the surgeon should expect an abnormal position of the common peroneal nerve and appreciate the increased risk of iatrogenic damage.
Growth as a corrective force in the early treatment of progressive infantile scoliosis
Authors: Mehta M. H.
Published: August 2005

This prospective study of 136 children with progressive infantile scoliosis treated under the age of four years, and followed up for nine years, shows that the scoliosis can be reversed by harnessing the vigorous growth of the infant to early treatment by serial corrective plaster jackets.

In 94 children (group 1), who were referred and treated in the early stages of progression, at a mean age of one year seven months (6 to 48 months) and with a mean Cobb angle of 32° (11° to 65°), the scoliosis resolved by a mean age of three years and six months. They needed no further treatment and went on to lead a normal life. At the last follow-up, their mean age was 11 years and two months (1 year 10 months to 25 years 2 months), 23 (24.5%) were at Risser stages 4 and 5 and 13 girls were post-menarchal.

In 42 children (group 2), who were referred late at a mean age of two years and six months (11 to 48 months) and with a mean Cobb angle of 52° (23° to 92°), treatment could only reduce but not reverse the deformity. At the last follow-up, at a mean age of ten years and four months (1 year 9 months to 22 years 1 month), eight children (19%) were at Risser stages 4 and 5 and five girls were post-menarchal. Fifteen children (35.7%) had undergone spinal fusion, as may all the rest eventually.
Low-friction arthroplasty of the hip using alumina ceramic and cross-linked polyethylene
Authors: Wroblewski B. M. , Siney P. D. , Fleming P. A.
Published: August 2005

We report the results of our continued review of 11 total hip arthroplasties using 22.225 mm alumina ceramic femoral heads on a Charnley flanged stem, articulating with chemically cross-linked polyethylene. There was an initial bedding-in of up to 0.41 mm at the articular surface in the first two years. This had not progressed further, at a minimum follow-up of 15 years. Radiographically no femoral or acetabular component showed loosening or osteolysis.
Recovery of knee function following fracture of the tibial plateau
Authors: Gaston P. , Will E. M. , Keating J. F.
Published: August 2005

We assessed the functional outcome following fracture of the tibial plateau in 63 consecutive patients. Fifty-one patients were treated by internal fixation, five by combined internal and external fixation and seven non-operatively. Measurements of joint movement and muscle function were made using a muscle dynamometer at three, six and 12 months following injury. Thirteen patients (21%) had a residual flexion contracture at one year. Only nine (14%) patients achieved normal quadriceps muscle strength at 12 months, while 19 (30%) achieved normal hamstring muscle strength. Recovery was significantly slower in patients older than 40 years of age. We conclude that there is significant impairment of movement and muscle function after fracture of the tibial plateau and that the majority of patients have not fully recovered one year after injury.
The MRI diagnosis and management of incomplete intertrochanteric fractures of the femur
Authors: Alam A. , Willett K. , Ostlere S.
Published: August 2005

Incomplete intertrochanteric fractures do not extend across to the medial femoral cortex and are stable, without rotational deformity or shortening of the lower limb. The aim of our study was to establish whether they can be successfully managed conservatively. A total of 68 patients over a five-year period presented with a suspected fracture of the femoral neck and underwent an MRI scan for further assessment. From these, we retrospectively reviewed eight patients with normal plain radiographs but with an incomplete, intertrochanteric fracture on MRI scan. Five were managed conservatively and three operatively.

The mean length of hospital stay was 16 days for the conservatively-treated group and 15 days for those who underwent surgery; this was not statistically significant (p > 0.5) and all patients were mobilised on discharge. Although five patients were readmitted at a mean of 3.2 years after discharge, none had progressed to a complete fracture. We believe that patients with incomplete intertrochanteric fractures should be considered for conservative treatment.
The significance of at-risk factors in ultrasound surveillance of developmental dysplasia of the hip
Authors: Paton R. W. , Hinduja K. , Thomas C. D.
Published: August 2005

Of the 34 723 infants born between 1 June 1992 and 31 May 2002, the hips of 2578 with clinical instability or at-risk factors for developmental dysplasia of the hip were imaged by ultrasound.

Instability of the hip was present in 77 patients, of whom only 24 (31.2%) had an associated risk factor. From the ‘at-risk’ groups, the overall risk of type-III dysplasia, instability and irreducibility was 1:15 when family history, 1:27 when breech delivery and 1:33 when foot deformity were considered as risk factors. Of those hips which were ultrasonographically stable, 88 had type-III dysplasia.

A national programme of selective ultrasound screening of at-risk factors for the diagnosis of hip dislocation or instability alone cannot be recommended because of its low predictive value (1:88). However, the incidence of type-III dysplasia and hip dislocation or dislocatability in the groups with clinical instability, family history, breech position and possibly postural foot deformity as risk factors could justify a programme of selective ultrasound imaging.
Transient osteoporosis of the knee following trauma
Authors: El Masry M. A. , Saha A. , Calder S. J.
Published: August 2005

Transient osteoporosis is an uncommon, self-limiting, reversible condition. We report a case involving the knee following trauma. The aetiology is unknown, but the association between transient osteoporosis and trauma has not been documented previously. The clinical presentation represents a degree of overlap among various clinical syndromes, including reflex sympathetic dystrophy and avascular necrosis. The diagnosis was confirmed by bone scan and MRI. The patient, a 47-year-old man, was treated with non-steroidal anti-inflammatory medication, protected weight-bearing and physiotherapy. He made a full clinical recovery and bone quality returned to virtual normality.
Superficial incisional infection in arthroplasty of the lower limb
Authors: Allami M. K. , Jamil W. , Fourie B. , Ashton V. , Gregg P. J.
Published: August 2005

The Department of Health and the Public Health Laboratory Service established the Nosocomial Infection National Surveillance Scheme in order to standardise the collection of information about infections acquired in hospital in the United Kingdom and provide national data with which hospitals could measure their own performance. The definition of superficial incisional infection (skin and subcutaneous tissue), set by the Center for Disease Control (CDC), should meet at least one of the defined criteria which would confirm the diagnosis and determine the need for specific treatment.

We have assessed the interobserver reliability of the criteria for superficial incisional infection set by the CDC in our current practice. The incisional site of 50 patients who had an elective primary arthroplasty of the hip or knee was evaluated independently by two orthopaedic clinical research fellows and two orthopaedic ward sisters for the presence or absence of surgical-site infection. Interobserver reliability was assessed by comparison of the criteria for wound infection used by the four observers using kappa reliability coefficients. Our study demonstrated that some of the components of the current CDC criteria were unreliable and we recommend their revision.
Fatal haemorrhage following a low-energy fracture of the pubic ramus
Authors: Coupe N. J. , Patel S. N. , McVerry S. , Wynn-Jones C. H.
Published: August 2005

We report a case of fatal haemorrhage following a low-energy fracture of the pubic ramus in an 85-year-old woman.
Stock–Yield Model for a Fish with Variable Annual Recruitment
Authors: Donald David B. , Aitken William
Published: August 2005

Many fish populations have variable annual recruitment, which challenges both population model development and conventional management strategies. Here, we develop a stock– yield model to assess the sustainability of the commercial catch of goldeye Hiodon alosoides from western Lake Athabasca of northeastern Alberta, Canada. Goldeyes have highly irregular annual recruitment; many year-classes are poor and dominant year-classes appear an average of only 1.7 times per decade. In the late 1990s, the mean annual commercial catch from this population was about 11,500 goldeyes—primarily fish from the 1982 and 1989 year-classes. A best-fit stock–yield model developed for this population incorporated (1) the restrictions of the catch from a historic fishery that depleted this population during the 1950s and early 1960s; (2) the restrictions of the known total stock size in the early 1970s, obtained from mark–recapture studies; (3) long-term annual estimates and patterns for stock recruitment (1972–2008); (4) a natural annual mortality rate of 20%; and (5) stock estimates for 1994 obtained from the catchability coefficient (catch per unit effort divided by the magnitude of commercial stock estimated from mark–recapture data for 1972 and 1973). The model suggested that an annual commercial catch of 10,000 goldeyes was sustainable over all years and conditions (1947–2004). This small modeled catch, about 2% of the long-term mean stock number of 540,000 goldeyes, ensured that at least a few thousand mature goldeyes would survive to spawn through periods of poor stock recruitment lasting more than a decade. These results suggest that fish populations with irregular annual recruitment can sustain only a low exploitation rate to prevent stock extinction during long periods of low recruitment.
Steelhead Emigration in a Seasonal Impoundment Created by an Inflatable Rubber Dam
Authors: Manning David J. , Mann Jonathon A. , White Sean K. , Chase Shawn D. , Benkert Ron C.
Published: August 2005

While large, permanent dams and reservoirs are known to impede smolt movements, investigations of small, temporary impoundments are scarce. Inflatable rubber bladder dams are used to create temporary impoundments worldwide, yet downstream fish passage at these structures has not been evaluated. To examine smolt emigration in a seasonal water supply reservoir and passage at a rubber dam, we tracked 110 radio-tagged steelhead Oncorhynchus mykiss smolts through a 4.5-km free-flowing reach and an adjacent 5.1-km-long impoundment on the Russian River, California, during 2001, 2002, and 2004. Unlike the results of studies in other impoundments, median travel rates in the free-flowing (0.6–0.8 km/h) and reservoir (1.0–1.4 km/h) reaches did not differ significantly within or among years. Smolts slowed significantly, however, in the dam forebay. Forebay travel rates (0.02–0.1 km/h) were more than an order of magnitude lower than rates in free-flowing and reservoir reaches. Although delayed, more than 75% of the fish detected in the forebay successfully passed the dam. More than 80% of the passing fish traveled over the dam crest as opposed to through ladders and flow bypasses. To determine whether increased spill depth and velocity would reduce forebay delay, we deformed the crest of the inflatable dam into a notched configuration throughout the 2004 study year. The notched configuration increased crest depth and velocity approximately 20-fold over the normal fully inflated condition. Smolts moved significantly faster through the forebay when the dam crest was notched in 2004 (median = 2.4 h) than when the dam was fully inflated in 2001 (6.3 h). Our finding that steelhead traveled through free-flowing and impounded reaches at similar rates but slowed dramatically in the forebay should encourage others to examine forebay conditions in small reservoirs. Concentrating spill by deforming the crest of an inflatable rubber dam is a simple and effective way of reducing forebay delay.
Hooking Mortality and Physiological Responses of Striped Bass Angled in Freshwater and Held in Live-Release Tubes
Authors: Bettinger Jason M. , Tomasso Joseph R. , Isely J. Jeffery
Published: August 2005

Mortality and physiological responses of adult striped bass Morone saxatilis angled from Lake Murray, South Carolina, and held in live-release tubes were evaluated during the spring and summer of 2003. To estimate mortality, we attached external ultrasonic transmitters to 59 striped bass (mean total length (TL) = 585 mm). Striped bass were caught with angling gear, tagged, and immediately released or held in live-release tubes for 2, 4, or 6 h prior to release. No mortality of striped bass was observed during spring. Overall mortality during summer was 83%. Mortality of summer-caught striped bass was not related to tube residence time, fish TL, depth of capture, or surface water temperature. To characterize physiological stress, we measured the plasma cortisol, glucose, lactate, and osmolality levels of 62 additional striped bass (mean TL = 563 mm) that were angled and immediately released or angled and held in live-release tubes. Plasma cortisol, glucose, lactate, and osmolality were positively related to tube residence time. When the hematological characteristics were considered only in relation to tube residence time, responses indicative of physiological stress continued for about 150 min, after which blood chemistry began to return to normal. Live-release tubes appear to be useful for keeping striped bass alive when they are angled from cool water, but they are not effective for striped bass angled from warm water. The high summer mortality of striped bass suggests a need for restrictive fishing regulations during the summer for the Lake Murray striped bass fishery.
Thiamine Status of Cayuga Lake Rainbow Trout and Its Influence on Spawning Migration
Authors: Ketola H. George , Chiotti Thomas L. , Rathman Robert S. , Fitzsimons John D. , Honeyfield Dale C. , Van Dusen Peter J. , Lewis Graham E.
Published: August 2005

Rainbow trout Oncorhynchus mykiss in Cayuga Lake, New York, appear to be suffering from a thiamine deficiency because their progeny develop general weakness, loss of equilibrium, and increased mortality, which are prevented by treatment with thiamine. Thiamine status and its effect on adults are unknown. In 2000 and 2002, we captured, tagged, and released 64 and 189 prespawning rainbow trout, respectively, in Cayuga Inlet at a collection weir to evaluate their thiamine status and the effect of thiamine injection (150 nmol/g) on instream migration. Half of the rainbow trout in each year (32 in 2000 and 95 in 2002) were injected with thiamine and half were uninjected; all rainbow trout were released above the weir to continue their upstream migration. By means of electrofishing in 2000, we recaptured significantly more thiamine-injected (N = 7) than uninjected (N = 0) rainbow trout approximately 7.0–9.3 river kilometers upstream from the weir. In 2002, the concentration of thiamine in the muscle of rainbow trout collected above a 1.8-m cascade was significantly higher (mean ± SD = 5.47 ± 5.04 nmol/g; range = 1.0– 13.8 nmol/g; N = 8) than that of rainbow trout collected either above a 1.0-m cascade (1.36 ± 0.71 nmol/g; range = 0.6–3.3 nmol/g; N = 16) or below the cascades (1.20 ± 0.46 nmol/g; range = 0.7–1.9 nmol/g; N = 5). The lowest concentration of thiamine observed in the muscle of rainbow trout collected upstream of the 1.8-m cascade was 1.0 nmol/g, suggesting that the threshold concentration required for rainbow trout to ascend the cascade was no more than that. Analyses of thiamine in the muscle of 26 untagged rainbow trout captured in Cayuga Inlet in 2002 showed that 16 fish (62%) had at least 1.0 nmol/g, which was apparently sufficient to support vigorous migration.
Have Different Inducements Used with the Western Rock Lobster Mail Survey of Recreational Licensees Had an Effect on Total Catch Estimates?
Authors: Thomson Adrian W. , Melville-Smith Roy
Published: August 2005

Mail surveys have been used over the last 17 years to estimate the recreational catch of western rock lobster Panulirus cygnus in an Australian fishery. Because nonresponse bias has been recognized as having a likely effect on these survey results, different inducements have been used over the years to increase returns. If these inducements have succeeded in reducing the effects of nonresponse bias, a catch model built from the resulting catch estimates would need to include inducement as a factor. At the end of the 2002–2003 season, 5,000 recreational license holders were sent identical surveys, along with one of the six different inducements that had been tried in previous seasons. The results showed that none of the inducements was likely to have affected total catch estimates in previous seasons. The age of the licensee and the license type held were identified as possible strata for future mail surveys to help reduce nonresponse bias.
Determining Optimal Stocking Rates Using a Stock–Recruitment Model: An Example Using Walleye in Northern Wisconsin
Authors: Fayram Andrew H. , Hansen Michael J. , Nate Nancy A.
Published: August 2005

We propose that stock–recruitment models can be used to estimate optimal stocking rates. Data to estimate the optimal stocking rates can be obtained in a relatively short amount of time by sampling similar populations over a few years. Whether the goal of stocking is endangered species recovery or supplementation of recreational fisheries, accurately determining the optimal stocking rate is of ecological and financial importance. As an example, we applied this approach using a Ricker stock–recruitment model to walleye Sander vitreus stocking in northern Wisconsin lakes. Using June stocking data and fall age-0 survey data for 39 lakes over a 14-year time period, we found that the stocking rate resulting in the greatest number of age-0 walleyes was 60 age-0 walleyes/ha. Similarly, using June stocking data and fall age-1 survey data in 18 lakes over a 9-year time period we found that the stocking rate resulting in the greatest number of age-1 walleyes was 75 age-0 walleyes/ha. About 16% of the variation in fall age-0 walleye density was explained by the stocking rate, and 28% of the variation in fall age-1 walleye density was explained by the stocking rate. Density-dependent survival was apparent and significant, as low and high stocking densities resulted in lower age-0 and age-1 juvenile walleye densities. The lake surface area explained a significant amount of the residual variation in the age-1 stock–recruitment relationship such that stocked walleyes generally survived at lower rates in large lakes than in small lakes, which may be due to a greater diversity of predators in larger lakes. Based on our analysis, we recommend stocking small fingerling walleyes at a rate of 75 fish/ha in northern Wisconsin lakes.
A New Method to Compute Standard-Weight Equations That Reduces Length-Related Bias
Authors: Gerow Kenneth G. , Anderson-Sprecher Richard C. , Hubert Wayne A.
Published: August 2005

We propose a new method for developing standard-weight (Ws) equations for use in the computation of relative weight (Wr) because the regression line–percentile (RLP) method often leads to length-related biases in Ws equations. We studied the structural properties of Ws equations developed by the RLP method through simulations, identified reasons for biases, and compared Ws equations computed by the RLP method and the new method. The new method is similar to the RLP method but is based on means of measured weights rather than on means of weights predicted from regression models. The new method also models curvilinear Ws relationships not accounted for by the RLP method. For some length-classes in some species, the relative weights computed from Ws equations developed by the new method were more than 20 Wr units different from those using Ws equations developed by the RLP method. We recommend assessment of published Ws equations developed by the RLP method for length-related bias and use of the new method for computing new Ws equations when bias is identified.
A Comparison of Visual and Measurement-Based Techniques for Quantifying Cobble Embeddedness and Fine-Sediment Levels in Salmonid-Bearing Streams
Authors: McHugh Peter , Budy Phaedra
Published: August 2005

Excess fine-sediment loading can strongly affect the performance of salmonids rearing in fluvial habitats. Consequently, there are multiple techniques for quantifying the biologically relevant aspects of streambed material quality. While similar methods should provide similar measurements for a given attribute, little information is available that validates this assumption. Nevertheless, there are ongoing efforts toward assembling and analyzing large-scale habitat databases using existing information collected via multiple techniques. For these reasons, we used regression to compare visual and measurement-based approaches for two commonly assessed substrate variables (cobble embeddedness and percent surface fines). For both embeddedness and percent fines, we found moderate to strong linear relationships (R2 = 0.46–0.83) between estimates obtained by visual and measurement-based approaches. However, the fitted line differed significantly from a null 1:1 expectation for the percent fines and embeddedness analyses, indicating that there is a differential bias between visual and measurement-based techniques relative to the true, but unknown, value. The observed deviation between embeddedness methods, which is primarily due to differences in measurement strategy, is probably of considerable practical significance. Conversely, the difference between techniques for percent fines appears to be negligible considering published information on observer variability for this attribute. In summary, our study provides a means for understanding and accounting for differences in substrate methods of direct relevance to large-scale habitat assessment efforts.
Age, Growth, Relative Abundance, and Scuba Capture of a New or Recovering Spawning Population of Lake Sturgeon in the Lower Niagara River, New York
Authors: Hughes Thomas C. , Lowie Christopher E. , Haynes James M.
Published: August 2005

The objective of our study was to collect age, growth, and catch-per-unit-effort information from a new or recovering population of lake sturgeon Acipenser fulvescens in the lower Niagara River, New York. From July 1998 through August 2000, we captured 67 lake sturgeon by use of gill nets, baited setlines, and scuba diving. Active capture by scuba divers (1.50 fish/ h) was much more effective than passive capture with gill nets (0.07 fish/h) and setlines (0.06 fish/h). Eggs of Chinook salmon Oncorhynchus tshawytscha were more effective as setline bait than were alewives Alosa pseudoharengus, but neither bait differed in effectiveness from rainbow smelt Osmerus mordax. Ages of captured lake sturgeon ranged from 1 to 23 years; 47 of the 61 aged fish were younger than age 10. Strong relationships were found between weight, W, and length, L (W = 0.0000005 · L3.5564; R2 = 0.977) and between L and age (L = 394.05 · loge(age) + 248.77; R2 = 0.878). The lake sturgeon population in the lower Niagara River is probably small relative to its historic abundance. This naturally reproducing population should remain listed as threatened by New York State, and commercial and recreational fisheries should remain closed so that the population can rebuild adult numbers and reproductive potential.
Extent and Distribution of Genetic Variation in U.S. Maize: Historically Important Lines and Their Open‐Pollinated Dent and Flint Progenitors
Authors: Ho J. C. , Kresovich S. , Lamkey K. R.
Published: August 2005

Ancestral open‐pollinated populations of U.S. maize (Zea mays L.) are a resource to broaden the genetic base of modern maize and to ensure long‐term gains in maize breeding. We report the extent and distribution of simple sequence repeat (SSR) variation in a comprehensive study of Northern Flints (NFs), Southern Dents (SDs), Corn Belt Dents (CBDs), and historically important inbred lines, and address their implications for maize improvement and conservation. We found that the loss of rare alleles in open‐pollinated cultivars from elite gene pools resulted in the divergence of inbred lines as a distinct group apart from their progenitor races. In contrast, the Corn Belt Dent cultivars retained high levels of genetic variation that approximated or exceeded that found in their NF and SD progenitors. Within open‐pollinated varieties, the absence of any clear pattern of population differentiation indicates frequent admixture, a relatively recent time of divergence, or poor correlation between the degree of divergence at neutral marker loci and quantitative trait variation. This research suggests that the inbred lines currently used by breeders as the primary genetic resource for line improvement do not represent the genetic variation available in the temperate races from which they are derived: only 56% of the alleles found in the Corn Belt Dents were displayed in a diverse set of inbred lines. Extensive sampling targeted at a limited number of Corn Belt Dent cultivars is a promising approach toward the identification and introgression of rare alleles that were lost during early inbred development or the maintenance of open‐pollinated populations.
Potential Heterotic Groups in Hop as Determined by AFLP Analysis
Authors: Townsend M. Shaun , Henning John A.
Published: August 2005

Hop (Humulus lupulus L.) is a perennial, dioecious species in which the female inflorescence (cones) are harvested and used in the beer‐brewing process to impart bittering and/or flavoring to beer. Hop breeders have typically utilized clonal selection and hybridization to develop new cultivars. The use of genetically diverse parents for the purpose of capturing heterosis in the offspring has received little attention from hop breeders. The objective of this research was to assign male (N = 80) and female (N = 26) hop genotypes into potential heterotic groups using AFLP‐generated molecular markers. The six AFLP primers used in this study amplified 550 total fragments, of which 490 (89.1%) were polymorphic. A genetic distance (GD) matrix was computed from the binary data matrix, and groupings and summary statistics were calculated from the GD matrix. Two major clusters were observed, one composed primarily of European hops, while the second group was composed primarily of European–wild American hybrids. The two major clusters were further subdivided into 13 smaller clusters (two female, nine male, two male and female) based on a qualitative analysis. These results suggest potential parental combinations for hop researchers and breeders to study heterosis in hop.
Crop Production Factors Associated with Fusarium Head Blight in Spring Wheat in Eastern Saskatchewan
Authors: Fernandez M. R. , Selles F. , Gehl D. , DePauw R. M. , Zentner R. P.
Published: August 2005

Fusarium head blight (FHB) has been increasing in western regions of the Canadian Prairies. The objective of this 4‐yr study was to identify crop production factors (CPF), associated with FHB development in spring wheat (Triticum aestivum L.). From 1999 to 2002, 659 crops were sampled in eastern Saskatchewan for FHB levels, and information gathered on agronomic practices used on these fields. In 2000 and 2001, percent Fusarium‐damaged kernels (FDK) was also determined. Differences in the FHB index among years indicated that environment was the most important factor affecting disease development. The effects of CPFs on FHB were lower in years with high (2001) and low (1999 and 2002) disease pressure, compared with a year with moderate (2000) disease pressure. Previous application of glyphosate [N‐(phosphonomethyl)glycine] formulations (GF) within tillage system, tillage system, previously grown crop, and cultivar susceptibility were the only CPFs that affected FHB. GF application in the previous 18 mo within tillage system was significantly associated with higher FHB levels every year; it was the only CPF in 1999, and one of two CPFs in 2002, that affected FHB, suggesting that its effect was not influenced as much by environmental conditions as that of other CPFs. Percentage FDK was also higher in fields previously treated with GF in 2000 and 2001. Because of the nature of this study, we could not determine if the association between previous GF use and FHB development was a cause–effect relationship. Thus, further research is needed to elucidate the nature of this association and the underlying mechanisms.
Characteristics in Diverse Wear Tolerant Genotypes of Kentucky Bluegrass
Authors: Brosnan J. T. , Ebdon J. S. , Dest W. M.
Published: August 2005

Evaluations of Kentucky bluegrass (Poa pratensis L.) wear tolerance have been conducted; however, studies investigating wear mechanisms within this species is limited. This information would be valuable in selecting wear tolerant genotypes. The objective of this study was to identify anatomical and morphological characteristics in diverse wear tolerant Kentucky bluegrasses. Wear treatments were applied to the 2000 National Turfgrass Evaluation Program (NTEP) Kentucky bluegrass field plots in the fall of 2002 at the University of Massachusetts Joseph Troll Turf Research Center at South Deerfield, MA. Wear treatments were applied to 173 genotypes with a differential slip‐wear apparatus, and plots were visually rated for wear injury. The 10 most wear tolerant (TOL) and intolerant (INTOL) genotypes were selected for further evaluation. Twelve characteristics were measured in 2003 and 2004 comparing TOL and INTOL genotypes in field plots and as greenhouse grown spaced‐plants. Characteristics included tiller density, shoot fresh weight and dry weight, shoot water content, leaf turgidity, number of leaves per shoot, leaf width, leaf strength, leaf angle, and leaf cell wall constituents [total cell wall content (TCW), hemicellulose, and lignocellulose]. Not all differences observed in the greenhouse were present in field plots. Significant differences were found between genotypes and TOL and INTOL groupings. No significant interaction with year was detected. Tolerant genotypes were associated with a more vertical leaf angle, greater TCW and lignocellulose content, and a lower shoot moisture content and leaf turgidity. Leaf angle was the single most important attribute separating wear TOL and INTOL genotypes. Biological explanation for the relationship between leaf orientation and wear tolerance is proposed. These characteristics may be useful as potential selection criteria for breeding to improve wear tolerance within this species.