bluuebunny/crossref_metadata_2025 huggingface dataset:
Comorbidity, Disability, and Geriatric Syndromes in Elderly Cancer Patients Receiving Home Health Care
Authors: Koroukian Siran M. , Murray Patrick , Madigan Elizabeth
Published: May 2006

Purpose

To assess the prevalence of comorbidity, disability, and geriatric syndromes, or a combination thereof, in elders with cancer receiving home health care (HHC).

Patients and Methods

Using the Ohio Cancer Incidence Surveillance System, we identified Ohio residents 65 years of age or older who were diagnosed with incident breast (n = 952), prostate (n = 324), or colorectal cancer (n = 1,276) during the 28-month study period, August 1999 through November 2001. We used the Outcome and Assessment Information Set, a database compiling comprehensive assessment forms completed for all HHC patients, to group individuals in independent and overlapping categories of comorbidity, disability, and geriatric syndromes on the basis of the patients' clinical condition 14 days before the date of the assessment.

Results

The proportion with no comorbidity, disability, or geriatric syndromes was 26.4% in breast cancer patients, 12.0% in prostate cancer patients, and 14.0% in colorectal cancer patients. The proportion of patients presenting all three entities at once was 11.7%, 24.7%, and 15.7%, respectively, in three cancer sites. As expected, the proportion of patients with no comorbidity, disability, or geriatric syndromes declined gradually with increasing age, and that of patients with all three entities was highest among patients 85 years or older.

Conclusion

The proposed taxonomy will help us gain a more nuanced understanding of older cancer patients' clinical presentation and may lead to a more accurate identification of older patients who might benefit from standard cancer treatment, and those who might experience adverse outcomes.
Immunohistochemical Test for MLH1 and MSH2 Expression Predicts Clinical Outcome in Stage II and III Colorectal Cancer Patients
Authors: Lanza Giovanni , Gafà Roberta , Santini Alessandra , Maestri Iva , Guerzoni Laura , Cavazzini Luigi
Published: May 2006

Purpose

To evaluate the prognostic significance of DNA mismatch repair (MMR) status in a large series of stage II and III colorectal cancer patients. The relationship among MMR status, adjuvant chemotherapy, and clinical outcome was also investigated.

Patients and Methods

The study included 718 patients with colorectal adenocarcinoma (393 stage II and 325 stage III) who underwent curative surgical resection. MMR status was determined by immunohistochemical analysis of MLH1 and MSH2 expression. Microsatellite instability (MSI) was assessed in 363 patients using mononucleotide and dinucleotide markers.

Results

One hundred fourteen (15.9%) carcinomas showed abnormal MMR protein (MMRP) expression (96 MLH1 negative and 18 MSH2 negative) and were classified as MMRP negative, whereas 604 tumors demonstrated normal MLH1/MSH2 immunoreactivity (MMRP positive). MLH1/MSH2 expression was closely related to MSI status (P < .001) and several clinicopathologic features. Patients with MMRP-negative carcinomas demonstrated a marked reduction in the risk of cancer-related death with respect to patients with MMRP-positive tumors (hazard ratio, 0.2579; 95% CI, 0.1289 to 0.5159). A better clinical outcome for patients with MMRP-negative tumors was observed in both stage II (P = .0006) and stage III (P = .0052) disease. In stage III disease, the survival advantage conferred by MMRP-negative tumors was more evident among patients treated with surgery alone than among patients who received adjuvant chemotherapy. A nonsignificant trend for survival benefit from adjuvant chemotherapy was observed among patients with MMRP-positive carcinomas but not among those with MMRP-negative carcinomas.

Conclusion

Immunohistochemical testing for MLH1/MSH2 expression provides useful prognostic information for the management of stage II and III colorectal cancer patients.
Indium-111–Labeled Trastuzumab Scintigraphy in Patients With Human Epidermal Growth Factor Receptor 2–Positive Metastatic Breast Cancer
Authors: Perik Patrick J. , Lub-De Hooge Marjolijn N. , Gietema Jourik A. , van der Graaf Winette T.A. , de Korte M. Alexander , Jonkman Sharon , Kosterink Jos G.W. , van Veldhuisen Dirk J. , Sleijfer Dirk T. , Jager Pieter L. , de Vries Elisabeth G.E.
Published: May 2006

Purpose

The cardiac and antineoplastic effects of trastuzumab may be related to specific uptake of trastuzumab in myocardium and tumor tissue, respectively. We evaluated whether indium-111 (111In) –labeled trastuzumab scintigraphy can predict cardiotoxicity and identify tumor lesions. In addition, we evaluated whether plasma markers for cardiac dysfunction can be used to predict cardiotoxicity.

Patients and Methods

Patients with human epidermal growth factor receptor 2 (HER2) –positive metastatic breast cancer underwent gamma camera imaging from 15 minutes to 7 days after injection of 150 MBq 111In–diethylenetriamine penta-acetic acid anhydride (DTPA) –trastuzumab, after loading-dose trastuzumab, and after once-a-week trastuzumab doses for 11 weeks, and concomitant paclitaxel once every 3 weeks. Cardiac assessments were performed before treatment, and after four and six cycles. Plasma N-terminal probrain natriuretic peptide (NT-proBNP) and serum troponin I were measured with immunoassay.

Results

Fifteen of the 17 patients were available for cardiac and tumor uptake analysis. On the first scan, myocardial 111In-DTPA-trastuzumab uptake was observed in one patient with pre-existing cardiac arrhythmias, who did not develop heart failure during treatment. Severe cardiotoxicity occurred in three patients, without initial myocardial uptake, whereas one showed weak myocardial uptake after four cycles. The detection rate of single tumor lesions was 45%. New tumor lesions were discovered in 13 of 15 patients. Pretreatment plasma NT-proBNP levels were higher in patients with than without heart failure (mean, 534 [standard deviation, 236] v 105 [standard deviation, 79] ng/L; P = .009).

Conclusion

Radiolabeled trastuzumab scintigraphy was not valuable in predicting trastuzumab-related cardiotoxicity in metastatic breast cancer patients, but can identify HER2-positive tumors. Measurement of plasma NT-proBNP is promising regarding prediction of trastuzumab-related cardiotoxicity.
Randomized Comparison of Every-2-Week Darbepoetin Alfa and Weekly Epoetin Alfa for the Treatment of Chemotherapy-Induced Anemia: The 20030125 Study Group Trial
Authors: Glaspy John , Vadhan-Raj Saroj , Patel Ravi , Bosserman Linda , Hu Eddie , Lloyd Richard E. , Boccia Ralph V. , Tomita Dianne , Rossi Greg
Published: May 2006

Purpose

Chemotherapy-induced anemia is widely treated in the United States with darbepoetin alfa (DA) or epoetin alfa (EA). This noninferiority study systematically compares efficacy and safety of DA and EA using common doses and schedules used in clinical practice.

Methods

Patients had a diagnosis of nonmyeloid malignancy with ≥ 8 weeks of planned chemotherapy, age ≥ 18 years, and anemia (hemoglobin ≤ 11 g/dL). Patients were randomly assigned 1:1 to DA 200 μg every two weeks (Q2W) or EA 40,000 units every week (QW) for up to 16 weeks with identical dose adjustment rules. Efficacy was assessed by the incidence of RBC transfusion (Kaplan-Meier estimate). The definition of noninferiority was that the upper 95% CI limit of the observed difference in RBC transfusions between groups was less than 11.5%; this noninferiority margin was based on the treatment effect observed in placebo-controlled EA studies.

Results

Of 1,220 patients randomly assigned, 1,209 received ≥ one dose of the study drug. Common tumor types were lung (26%), breast (21%), and gastrointestinal (18%). Transfusion incidence from week 5 to the end of the treatment phase (the primary end point) was 21% in the DA group and 16% in the EA group; noninferiority was concluded because the upper 95% CI limit of the difference between groups (10.8%) was below the prespecified noninferiority margin. Sensitivity analyses using alternate statistical methods and analysis sets yielded similar results. Hemoglobin, quality of life, and safety end points further support equivalency of the erythropoietic therapies.

Conclusion

This large, phase III study demonstrates comparable efficacy of DA Q2W and EA QW. Less frequent dosing offers potential benefits for patients, caregivers and health care providers.
Prognostic Significance of Blasts in the Cerebrospinal Fluid Without Pleiocytosis or a Traumatic Lumbar Puncture in Children With Acute Lymphoblastic Leukemia: Experience of the Dutch Childhood Oncology Group
Authors: te Loo D. Maroeska W.M. , Kamps Willem A. , van der Does-van den Berg Anna , van Wering Elisabeth R. , de Graaf Siebold S.N.
Published: May 2006

Purpose

To determine the significance of blasts in the CSF without pleiocytosis and a traumatic lumbar puncture in children with acute lymphoblastic leukemia (ALL).

Patients and Methods

We retrospectively studied a cohort of 526 patients treated in accordance with the virtually identical Dutch protocols ALL-7 and ALL-8. Patients were classified into five groups: CNS1, no blasts in the CSF cytospin; CNS2, blasts present in the cytospin, but leukocytes less than 5/μL; CNS3, blasts present and leukocytes more than 5/μL. Patients with a traumatic lumbar puncture (TLP; > 10 erythrocytes/mL) were classified as TLP+ (blasts present in the cytospin) or TLP− (no blasts).

Results

Median duration of follow-up was 13.2 years (range, 6.9 to 15.5 years). Event-free survival (EFS) was 72.6% (SE, 2.5%) for CNS1 patients (n = 304), 70.3% (SE, 4.7%) for CNS2 patients (n = 111), and 66.7% (SE, 19%) for CNS3 patients (n = 10; no significant difference in EFS between the groups). EFS was 58% (SE, 7.6%) for TLP+ patients (n = 62) and 82% (SE, 5.2%) for TLP− patients (n = 39; P < .01). Cox regression analysis identified TLP+ status as an independent prognostic factor (risk ratio, 3.5; 95% CI, 1.4 to 8.8; P = .007). Cumulative incidence of CNS relapses was 0.05 and 0.07 in CNS1 and CNS2 patients, respectively (not statistically significant).

Conclusion

In our experience, the presence of a low number of blasts in the CSF without pleiocytosis has no prognostic significance. In contrast, a traumatic lumbar puncture with blasts in the CSF specimen is associated with an inferior outcome.
Physical and Emotional Health Effects and Social Consequences After Participation in a Low-Fat, High-Carbohydrate Dietary Trial for More Than 5 Years
Authors: Hislop T. Gregory , Bajdik Chris D. , Balneaves Lynda G. , Holmes Andrea , Chan Selina , Wu Evelyn , Abanto Zenaida U. , Butler Andrea L.
Published: May 2006

Purpose

Little is known about the potential adverse effects of interventions to reduce dietary fat. We examined the physical and emotional health effects, and social consequences experienced by women at high risk for breast cancer who had participated in a low-fat diet intervention, randomized, controlled trial for at least 5 years.

Methods

Participants in the Canadian Diet and Breast Cancer Prevention Trial from British Columbia were mailed a survey questionnaire that included the validated Medical Outcomes Study 36-item Short Form Health Survey (SF-36) and Women's Health Questionnaire (WHQ), and a series of questions on health-related and social constructs. Responses were compared between the diet intervention and control groups by menopausal status.

Results

Completed questionnaires were returned by 359 women in the diet intervention group and 382 in the control group. No significant differences were found between these groups for SF-36 and WHQ health outcomes, hair/nail changes, physical activity levels, family/friend support levels, and doctor visits. Significantly more women in the intervention group reported taking products for arthritis (other than pain medication), greater difficulty in maintaining eating habits in social situations and at work, greater stress, and guilt related to personal eating habits. These findings persisted for both premenopausal and postmenopausal women.

Conclusion

Changes resulting from a low-fat diet intervention can be incorporated into women's daily lives with limited long-term negative effects.
Enterocolitis in Patients With Cancer After Antibody Blockade of Cytotoxic T-Lymphocyte–Associated Antigen 4
Authors: Beck Kimberly E. , Blansfield Joseph A. , Tran Khoi Q. , Feldman Andrew L. , Hughes Marybeth S. , Royal Richard E. , Kammula Udai S. , Topalian Suzanne L. , Sherry Richard M. , Kleiner David , Quezado Martha , Lowy Israel , Yellin Michael , Rosenberg Steven A. , Yang James C.
Published: May 2006

Purpose

Cytotoxic T-lymphocyte–associated antigen 4 (CTLA4) is an inhibitory receptor on T cells. Knocking out CTLA4 in mice causes lethal lymphoproliferation, and polymorphisms in human CTLA4 are associated with autoimmune disease. Trials of the anti-CTLA4 antibody ipilimumab (MDX-010) have resulted in durable cancer regression and immune-mediated toxicities. A report on the diagnosis, pathology, treatment, clinical outcome, and significance of the immune-mediated enterocolitis seen with ipilimumab is presented.

Patients and Methods

We treated 198 patients with metastatic melanoma (MM) or renal cell carcinoma (RCC) with ipilimumab.

Results

The overall objective tumor response rate was 14%. We observed several immune mediated toxicities including dermatitis, enterocolitis, hypophysitis, uveitis, hepatitis, and nephritis. Enterocolitis, defined by grade 3/4 clinical presentation and/or biopsy documentation, was the most common major toxicity (21% of patients). It presented with diarrhea, and biopsies showed both neutrophilic and lymphocytic inflammation. Most patients who developed enterocolitis responded to high-dose systemic corticosteroids. There was no evidence that steroid administration affected tumor responses. Five patients developed perforation or required colectomy. Four other patients with steroid-refractory enterocolitis appeared to respond promptly to tumor necrosis factor alpha blockade with infliximab. Objective tumor response rates in patients with enterocolitis were 36% for MM and 35% for RCC, compared with 11% and 2% in patients without enterocolitis, respectively (P = .0065 for MM and P = .0016 for RCC).

Conclusion

CTLA4 seems to be a significant component of tolerance to tumor and in protection against immune mediated enterocolitis and these phenomena are significantly associated in cancer patients.
Treatment of Anaplastic Histology Wilms' Tumor: Results From the Fifth National Wilms' Tumor Study
Authors: Dome Jeffrey S. , Cotton Cecilia A. , Perlman Elizabeth J. , Breslow Norman E. , Kalapurakal John A. , Ritchey Michael L. , Grundy Paul E. , Malogolowkin Marcio , Beckwith J. Bruce , Shamberger Robert C. , Haase Gerald M. , Coppes Max J. , Coccia Peter , Kletzel Morris , Weetman Robert M. , Donaldson Milton , Macklis Roger M. , Green Daniel M.
Published: May 2006

Purpose

An objective of the fifth National Wilms' Tumor Study (NWTS-5) was to evaluate the efficacy of treatment regimens for anaplastic histology Wilms' tumor (AH).

Patients and Methods

Prospective single-arm studies were conducted. Patients with stage I AH were treated with vincristine and dactinomycin for 18 weeks. Patients with stages II to IV diffuse AH were treated with vincristine, doxorubicin, cyclophosphamide, and etoposide for 24 weeks plus flank/abdominal radiation.

Results

A total of 2,596 patients with Wilms' tumor were enrolled onto NWTS-5, of whom 281 (10.8%) had AH. Four-year event-free survival (EFS) and overall survival (OS) estimates for assessable patients with stage I AH (n = 29) were 69.5% (95% CI, 46.9 to 84.0) and 82.6% (95% CI, 63.1 to 92.4). In comparison, 4-year EFS and OS estimates for patients with stage I favorable histology (FH; n = 473) were 92.4% (95% CI, 89.5 to 94.5) and 98.3% (95% CI, 96.4 to 99.2). Four-year EFS estimates for patients who underwent immediate nephrectomy with stages II (n = 23), III (n = 43), and IV (n = 15) diffuse AH were 82.6% (95% CI, 60.1 to 93.1), 64.7% (95% CI, 48.3 to 77.7), and 33.3% (95% CI, 12.2 to 56.4), respectively. OS was similar to EFS for these groups. There were no local recurrences among patients with stage II AH. Four-year EFS and OS estimates for patients with bilateral AH (n = 29) were 43.8% (95% CI, 24.2 to 61.8) and 55.2% (95% CI, 34.8 to 71.7), respectively.

Conclusion

The prognosis for patients with stage I AH is worse than that for patients with stage I FH. Novel treatment strategies are needed to improve outcomes for patients with AH, especially those with stage III to V disease.
Never-Smokers With Lung Cancer: Epidemiologic Evidence of a Distinct Disease Entity
Authors: Toh Chee-Keong , Gao Fei , Lim Wan-Teck , Leong Swan-Swan , Fong Kam-Weng , Yap Swee-Peng , Hsu Anne A.L. , Eng Philip , Koong Heng-Nung , Thirugnanam Agasthian , Tan Eng-Huat
Published: May 2006

Purpose

Tobacco smoke is a definite causative agent for lung cancer. It is increasingly being recognized that never-smokers can be afflicted with non–small-cell lung cancer (NSCLC). We aim to assess survival differences between smokers and never-smokers with NSCLC.

Patients and Methods

We analyzed 975 NSCLC patients who presented from January 1999 to December 2002. Clinical characteristics among current-, former- and never-smokers were tested using χ2 or Kruskal-Wallis test. The hazard ratio (HR) for death and its 95% CI were calculated by Cox regression.

Results

Of 975 patients, 59 had no smoking history and 33 had no quit time recorded. Of 883 patients analyzed, 286 patients (32.4%) were never-smokers. One hundred ninety-six never-smokers (68.5%) were females compared with 12% among current- and 13% among former-smokers (P < .001). There was a significant difference in histologic subtype between never-smokers and smokers: 69.9% with adenocarcinoma versus 39.9% (current-smokers) versus 47.3% (former-smokers); 5.9% with squamous cell carcinoma versus 35.7% (current-smokers) versus 28% (former-smokers; P < .001). Smokers had significantly poorer performance status (P = .002) and higher median age at diagnosis (P < .001) while more never-smokers presented with advanced disease (P = .002). Eight hundred and five patients (82.6%) died by May 30, 2005. The HR for smokers was significantly higher on both univariate and multivariate analysis (HR, 1.297; 95% CI, 1.040 to 1.619).

Conclusion

Never-smokers comprised a high proportion of NSCLC patients in Singapore. Definite epidemiologic differences exist between never-smokers and smokers. Differences in survival outcome further suggest that the biology underlying the pathogenesis and behavior of the disease may be different for never-smokers.
Clinical Outcomes and Prognostic Factors in Patients With Richter's Syndrome Treated With Chemotherapy or Chemoimmunotherapy With or Without Stem-Cell Transplantation
Authors: Tsimberidou Apostolia-Maria , O'Brien Susan , Khouri Issa , Giles Francis J. , Kantarjian Hagop M. , Champlin Richard , Wen Sijin , Do Kim-Anh , Smith Susan C. , Lerner Susan , Freireich Emil J. , Keating. Michael J.
Published: May 2006

Purpose

The purpose of this study was to assess the incidence, presenting characteristics, and treatment outcomes of Richter's syndrome (RS) and factors predicting response and survival.

Patients and Methods

An electronic database search of patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) who presented at The University of Texas M.D. Anderson Cancer Center (Houston, TX) between January 1975 and June 2005 was performed, and patient medical records were reviewed.

Results

Of the 3,986 patients with CLL/SLL, 204 patients (5.1%) had possible RS, and 148 patients (3.7%) had biopsy- or fine-needle aspiration–proven RS. Treatment included chemotherapy alone and chemoimmunotherapy with rituximab. The overall response rate for the 130 assessable patients was 39% (chemotherapy, 34%; chemoimmunotherapy, 47%; P = .2). In multivariate analysis, factors predicting prolonged survival were Zubrod performance status 0-1 (P = .006), lactate dehydrogenase ≤ 1.5× the upper limit of normal (P = .003), platelet count ≥ 100,000 (P = .01), tumor size ≤ 5 cm (P = .02), and fewer than two prior therapies (P = .02). The five adverse factors predicting shorter survival were used to design a model to predict an individual patient's risk of death: the RS score. A total of 20 patients underwent stem-cell transplantation (SCT). Patients who underwent allogeneic SCT as postremission therapy had longer survival than patients who achieved remission and received no additional therapy or patients who underwent allogeneic or autologous SCT as salvage therapy (P = .019).

Conclusion

A score to predict an individual patient's risk of death is proposed. Chemotherapy and rituximab combinations are effective in RS. Patients with available donors may be considered for allogeneic SCT as postremission therapy.
Surgical Management of Advanced Gastrointestinal Stromal Tumors After Treatment With Targeted Systemic Therapy Using Kinase Inhibitors
Authors: Raut Chandrajit P. , Posner Matthew , Desai Jayesh , Morgan Jeffrey A. , George Suzanne , Zahrieh David , Fletcher Christopher D.M. , Demetri George D. , Bertagnolli Monica M.
Published: May 2006

Purpose

While targeted inhibitors of tyrosine kinase activity demonstrate dramatic efficacy in the majority of patients with advanced gastrointestinal stromal tumors (GISTs), cure remains elusive and resistance to systemic therapy is a challenge. To assess the role of surgery in multimodality management of GISTs, we studied postoperative outcomes in patients treated with targeted kinase inhibitors for advanced GIST.

Methods

We evaluated outcomes in a single institution series of 69 consecutive patients who underwent surgery for advanced GISTs while receiving kinase inhibitors. Patients were categorized based on extent of disease before surgery (stable disease, limited disease progression, generalized disease progression) and surgical result (no evidence of disease, minimal residual disease, bulky residual disease).

Results

Disease status before surgery was associated with surgical result (P < .0001; median follow-up, 14.6 months). After surgery, there was no evidence of disease in 78%, 25%, and 7% of patients with stable disease, limited progression, and generalized progression, respectively. Bulky residual disease remained after surgery in 4%, 16%, and 43% of the patients with stable disease, limited progression, and generalized progression. Twelve-month progression-free survival was 80%, 33%, and 0% for patients with stable disease, limited progression, and generalized progression (P < .0001). Twelve-month overall survival was 95%, 86%, and 0% for patients with stable disease, limited progression, and generalized progression (P < .0001).

Conclusion

Patients with advanced GISTs exhibiting stable disease or limited progression on kinase inhibitor therapy have prolonged overall survival after debulking procedures. Surgery has little to offer in the setting of generalized progression.
Radiochemotherapy After Transurethral Resection for High-Risk T1 Bladder Cancer: An Alternative to Intravesical Therapy or Early Cystectomy?
Authors: Weiss Christian , Wolze Carolin , Engehausen Dirk Gerhard , Ott Oliver J. , Krause Frens S. , Schrott Karl-Michael , Dunst Jürgen , Sauer Rolf , Rödel Claus
Published: May 2006

Purpose

For high-risk T1 bladder cancer, the most important issue is how to restrict radical cystectomy to selective patients with a high likelihood of tumor progression and to choose an initial bladder-sparing approach in others without affecting survival. Radiotherapy or radiochemotherapy (RT/RCT) may help to strike a balance between intravesical treatment and early cystectomy.

Patients and Methods

Between 1982 and 2004, 141 patients with high-risk T1 bladder cancer (84 patients with T1 grade 3 [T1G3]; others with T1G1/2 and associated carcinoma-in-situ, multifocality, tumor diameter > 5 cm, or multiple recurrences) were treated with RT (n = 28) or platinum-based RCT (n = 113) after transurethral resection of bladder tumor (TURBT). Six weeks after RT/RCT, response was evaluated by restaging TURBT. Salvage cystectomy was recommended for patients with persistent disease and for tumor progression after initial complete response (CR). Median follow-up was 62 months; 65 patients have been observed for 5 years or more.

Results

CR was achieved in 121 of 137 patients (88%; four patients without restaging TURBT). Tumor progression for the entire group of 141 patients was 19% and 30% at 5 and 10 years, respectively (for 121 patients with CR, 15% and 29%; for 84 patients with T1G3, 13% and 29%, respectively). Disease-specific survival rates were 82% and 73% at 5 and 10 years (CR, 89% and 79%; T1G3, 80% and 71%, respectively). More than 80% of survivors preserved their bladder; 70.4% were “delighted” or “pleased” with their urinary function.

Conclusion

RT/RCT after TURBT with selective bladder preservation is a reasonable alternative to intravesical treatment or early cystectomy for high-risk T1 bladder cancer.
The Storyteller and the Book: Scenes of Narrative Production in the Early French Novel
Authors: Paige Nicholas
Published: May 2006

Nicholas Paige is associate professor of French at the University of California, Berkeley. He is author of Being Interior: Autobiography and the Contradictions of Modernity in Seventeenth-Century France (2001) and is currently researching the concepts of fiction, belief, and referentiality in seventeenth- and eighteenth-century France. A translation of Lafayette's Zayde: A Spanish Romance is forthcoming.
Decadence, Nationalism, and the Logic of Canon Formation
Authors: Potolsky Matthew
Published: May 2006

Matthew Potolsky is assistant professor of English at the University of Utah. He has published widely on literature of the late nineteenth and early twentieth centuries. He is coeditor of Perennial Decay: On the Aesthetics and Politics of Decadence (1999) and author of Mimesis (2006).
Spectral sensitivity of the two-spotted gobyGobiusculus flavescens(Fabricius): a physiological and behavioural study
Authors: Utne-Palm Anne C. , Bowmaker James K.
Published: May 2006

Microspectrophotometry of Gobiusculus flavescens photoreceptors revealed a single rod visual pigment (λmaxat 508 nm) and the three cone pigments (λmax 456, 531 and 553 nm). The cone population was dominated by identical double cones containing the middle-wave-sensitive (MWS)pigment, but with a small number of non-identical MWS/LWS(long-wave-sensitive) and identical LWS double cones. Small populations of large single cones also contained either the MWS or LWS pigment. The short-wave-sensitive (SWS) pigment was found in small single cones. Lens transmission was great reduced below 410 nm.

The spectral sensitivity of the behaviourally determined reaction distance(RD) to prey at a high irradiance level 0.5 μmol m-2s-1) correlated with the maximum sensitivity of the MWS cones, both peaking around 530 nm. However, at a lower irradiance level (0.015 μmol m-2 s-1)such a correlation was not so apparent. The RD was greatly reduced, though still maintaining a peak around 530-550 nm, but with a relatively smaller reduction in RD at shorter wavelengths. Optomotor behaviour displayed a somewhat similar spectral sensitivity to the RD responses at the higher light intensity. However, the peak was at slightly longer wavelengths at 550 nm, suggesting a greater input from LWS cones to the optomotor response.
Deciphering the organization and modulation of spinal locomotor central pattern generators
Authors: Gordon Ian T. , Whelan Patrick J.
Published: May 2006

Networks within our spinal cord generate the basic pattern underlying walking. Over the past decade, much progress has been made in our understanding of their function in a variety of vertebrate species. A significant hurdle has been the identification of candidate populations of neurons that are involved in pattern generation in the spinal cord. Recently,systems neuroscientists in collaboration with molecular biologists have begun to dissect the circuitry underlying spinal locomotor networks. These advances have combined genetic and electrophysiological techniques using in vitro preparations of the mouse spinal cord. This review will discuss new advances in the field of spinal locomotor networks with emphasis on the mouse.

Many of the behaviors fundamental to animal life, such as breathing,chewing and locomotion, are rhythmic activities controlled by neuronal networks. Discerning which neurons are members of these networks, their synaptic connectivity and their individual electrophysiological properties is essential to our understanding of how rhythmic motor behaviors are produced. It is well known that the spinal cord contains the basic circuitry to produce locomotion. However, identifying neurons and connections within spinal networks is challenging because cells that comprise the locomotor network form part of a heterogeneous mix of interneurons within the ventral spinal cord. Recently, the merging of electrophysiological and genetic approaches has provided new tools to identify classes of interneurons within the spinal cord that contribute to network function. These new findings will be discussed in this review.
The energetic costs of trunk and distal-limb loading during walking and running in guinea fowlNumida meleagris
Authors: Marsh Richard L. , Ellerby David J. , Henry Havalee T. , Rubenson Jonas
Published: May 2006

We examined the energetic cost of loading the trunk or distal portion of the leg in walking and running guinea fowl (Numida meleagris). These different loading regimes were designed to separately influence the energy use by muscles used during the stance and swing phases of the stride. Metabolic rate, estimated from oxygen consumption, was measured while birds locomoted on a motorized treadmill at speeds from 0.5 to 2.0 m s-1, either unloaded, or with a mass equivalent to 23% of their body mass carried on their backs, or with masses equal to approximately 2.5% of their body mass attached to each tarsometatarsal segment. In separate experiments, we also measured the duration of stance and swing in unloaded, trunk-loaded, or limb-loaded birds. In the unloaded and limb-loaded birds, we also calculated the mechanical energy of the tarsometatarsal segment throughout the stride.

Trunk and limb loads caused similar increases in metabolic rate. During trunk loading, the net metabolic rate (gross metabolic rate - resting metabolic rate) increased by 17% above the unloaded value across all speeds. This percentage increase is less than has been found in most studies of humans and other mammals. The economical load carriage of guinea fowl is consistent with predictions based on the relative cost of the stance and swing phases of the stride in this species. However, the available comparative data and considerations of the factors that determine the cost of carrying extra mass lead us to the conclusion that the cost of load carrying is unlikely to be a reliable indicator of the distribution of energy use in stance and swing. Both loading regimes caused small changes in the swing and/or stance durations, but these changes were less than 10%.

Loading the tarsometatarsal segment increased its segmental energy by 4.1 times and the segmental mechanical power averaged over the stride by 3.8 times. The increases in metabolism associated with limb loading appear to be linked to the increases in mechanical power. The delta efficiency (change in mechanical power divided by the change in metabolic power) of producing this power increased from 11% in walking to approximately 25% in running. Although tarsometatarsal loading was designed to increase the mechanical energy during swing phase, 40% of the increase in segmental energy occurred during late stance. Thus, the increased energy demand of distal limb loading in guinea fowl is predicted to cause increases in energy use by both stance- and swing-phase muscles.
Balancing the competing requirements of saltatorial and fossorial specialisation: burrowing costs in the spinifex hopping mouse,Notomys alexis
Authors: White Craig R. , Matthews Philip G. D. , Seymour Roger S.
Published: May 2006

Semi-fossorial animals (burrowing surface foragers) need to balance the competing morphological requirements of terrestrial and burrowing locomotion. These species rarely show the same degree of claw, forelimb and pectoral girdle structural development that fully fossorial forms (burrowing subterranean foragers) do, but nevertheless invest considerable amounts of energy in burrow systems. The compromise between terrestrial and burrowing locomotion was investigated by measuring net costs of burrowing and pedestrian transport in the spinifex hopping mouse, Notomys alexis, a species that forages in open areas in arid environments and is adapted for saltatorial locomotion. The net cost of transport by burrowing of hopping mice was found to be more expensive than for specialised fossorial species, and burrows were estimated to represent an energy investment equivalent to the terrestrial locomotion expected to be incurred in 17-100 days. A phylogenetically independent-contrasts approach revealed that morphological specialisation for burrowing was associated with low maximum running speeds in fossorial mammals and, for non-fossorial rodents and marsupials, maximum running speed was positively correlated with an index of habitat structure that ranged from arboreal to open desert. The high terrestrial speeds attainable by this semi-fossorial species by saltatory locomotion apparently outweigh the energetic savings that would be associated with burrowing specialisation.
Adaptive value of ambling gaits in primates and other mammals
Authors: Schmitt Daniel , Cartmill Matt , Griffin Timothy M. , Hanna Jandy B. , Lemelin Pierre
Published: May 2006

At speeds between the walk and the gallop, most mammals trot. Primates almost never trot, and it has been claimed that they transition directly from a walk to a gallop without any distinctive mid-speed running gait. If true,this would be another characteristic difference between the locomotion of primates and that of most other quadrupedal mammals. Presently, however, few data exist concerning the actual presence or absence of intermediate-speed gaits (i.e. gaits that are used between a walk and a gallop) in primates. Video records of running in twelve primate species reveal that, unlike most other mammals, all the primates studied almost exclusively adopt an `amble' -an intermediate-speed running gait with no whole-body aerial phase - rather than trot. Ambling is also common in elephants and some horses, raising the question of why ambling is preferred over trotting in these diverse groups of animals. Mathematical analyses presented here show that ambling ensures continuous contact of the body with the substrate while dramatically reducing vertical oscillations of the center of mass. This may explain why ambling appears to be preferable to trotting for extremely large terrestrial mammals such as elephants and for arboreal mammals like primates that move on unstable branches. These findings allow us to better understand the mechanics of these unusual running gaits and shed new light on primate locomotor evolution.
Locomotor function of the pectoral girdle `muscular sling' in trotting dogs
Authors: Carrier David R. , Deban Stephen M. , Fischbein Timna
Published: May 2006

In therian mammals, gravitational and locomotor forces are transferred between the forelimb and trunk primarily, or entirely, through the muscles that connect the limb and trunk. Our understanding of this force transmission is based on analyses of shoulder anatomy and on a handful of descriptive electromyographic studies. To improve our understanding, we manipulated the locomotor forces of trotting dogs and monitored the resulting change in recruitment of five extrinsic muscles of the forelimb: m. serratus ventralis thoracis, m. serratus ventralis cervicis, m. pectoralis superficialis transversus, the anterior portion of the m. pectoralis profundus, and m. rhomboideus thoracis. Locomotor forces were modified as the dogs trotted at constant speed on a motorized treadmill by (1) adding mass to the trunk, (2)inclining the treadmill so that the dogs ran up and down hill, (3) adding mass to the wrists and (4) applying horizontally directed force to the trunk through a leash. These experiments indicate that the thoracic portion of the serratus ventralis muscle is the main antigravity muscle of the shoulder during trotting in dogs. Its activity increased when we added mass to the trunk and also when we ran the subjects downhill. In contrast, the cervical portion of the serratus ventralis did not show a consistent increase in activity in response to added mass. Instead, its activity increased when we ran the subjects up hill and added mass to their wrists, suggesting that it functions to stabilize the fulcrum of the forelimb in the cranial-caudal direction during active retraction of the forelimb. The thoracic portion of the rhomboideus muscle also appears to provide this cranial-caudal stabilization during active retraction of the forelimb. The force manipulations indicate that the transverse pectoralis muscle acts to both protract and retract the forelimb, depending on the position of the limb. In contrast, the anterior portion of the pectoralis profundus muscle acts as a retractor of the forelimb during the end of swing phase and the beginning of support phase. We found that adding mass to the trunk did not increase the activity of forelimb retractor muscles, suggesting that the ground reaction force vector passes through, or very near, the fulcrum of the shoulder during a trotting step. Whether or not the functions of these extrinsic appendicular muscles in dogs characterize therian mammals or represent specializations for high-speed, economical running remains to be determined.
Time-domain signal divergence and discrimination without receptor modification in sympatric morphs of electric fishes
Authors: Arnegard Matthew E. , Jackson B. Scott , Hopkins Carl D.
Published: May 2006

Polymorphism in an animal communication channel provides a framework for studying proximate rules of signal design as well as ultimate mechanisms of signal diversification. Reproductively isolated mormyrid fishes from Gabon's Brienomyrus species flock emit distinctive electric organ discharges(EODs) thought to function in species and sex recognition. Species boundaries and EODs appear congruent in these fishes, with the notable exception of three morphs designated types I, II and III. Within the species flock, these morphs compose a monophyletic group that has recently been called the magnostipes complex. Co-occurring morphs of this complex express distinctive EODs, yet they appear genetically indistinguishable at several nuclear loci. In this study, we investigated EOD discrimination by these morphs using both behavioral and physiological experiments. During the breeding season, wild-caught type I and type II males showed evidence that they can discriminate their own morph's EOD waveform from that of a sympatric and genetically distinct reference species. However, we found that type I and type II males exhibited an asymmetry in unconditioned responses to paired playback of EODs recorded from type I versus type II females. Males of the type II morph responded preferentially to EODs of type II females,whereas type I males did not appear to discriminate homotypic and heterotypic EODs in our experimental paradigm. Part of this behavioral asymmetry may have resulted from a previously undetected difference in adult size, which may have enhanced apparent discrimination by the smaller morph (type II) due to a relatively higher risk of injury from the larger morph (type I). Knollenorgan receptors, which mediate electrical communication in mormyrids, showed similar spectral tuning in type I and type II. These electroreceptors coded temporal features of any single magnostipes-complex EOD with similar patterns of time-locked spikes in both morphs. By contrast, Knollenorgans exhibited distinctive responses to different EOD waveforms. These results suggest that discrete EOD variation in this rapidly diversifying complex is functional in terms of morph-specific advertisement and recognition. Time-domain signal divergence has outpaced frequency-domain divergence between sympatric morphs,requiring little to no change in receptor response properties. We discuss our findings in light of a model for EOD time-coding by the Knollenorgan pathway,as well as evolutionary hypotheses concerning sympatric signal diversification in the magnostipes complex.
Activation of a sensorimotor pathway in response to a water temperature drop in a teleost fish
Authors: van den Burg E. H. , Verhoye M. , Peeters R. R. , Meek J. , Flik G. , Van der Linden A.
Published: May 2006

When common carp, Cyprinus carpio L., experience a rapid temperature drop, the cerebral blood volume is strongly reduced to dampen the temperature drop in the brain. Simultaneously, the preoptic area and pituitary gland are activated to launch whole-body adaptive responses. However, the preferred reaction of fish to a temperature change is an escape reaction,which implies activation of a sensorimotor pathway. Here, we used blood oxygenation level-dependent (BOLD)- and cerebral blood volume (CBV)-weighted functional magnetic resonance imaging (fMRI) to identify a sensorimotor pathway, during a 10°C temperature drop in common carp. Transient activation was observed in the region where the sensory root of the trigeminal nerve enters the brain, and in the valvula cerebelli. In both regions,metabolic activity increased (increased deoxyhemoglobin content demonstrated by a decreased BOLD signal) within 30 s after the onset of the temperature drop, peaked after 2-3 min, and then decreased, even though the temperature continued to drop for another 2 min. These brain structures appear to respond to temperature change, rather than to the absolute temperature. Thus, during a temperature drop, the sensorimotor pathway consisting of the trigeminal nerve,the primary sensory trigeminal nucleus, the valvula cerebelli and some motornuclei, is active, in line with perception of temperature change in the buccal cavity, leading to motor activity for escape. This pathway operates in parallel to an acclimation pathway, which involves the preoptic area to pituitary gland pathway.
Steroid-induced cardiac contractility requires exogenous glucose,glycolysis and the sarcoplasmic reticulum in rainbow trout
Authors: Farrar Richard S. , Battiprolu Pavan K. , Pierson Nicholas S. , Rodnick Kenneth J.
Published: May 2006

Recent data from our laboratory suggest that sex steroids promote contractile function in cardiac muscle of rainbow trout (Oncorhynchus mykiss Walbaum), and there are sex differences in hormone signaling and cardiac function. The current study investigated whether steroid-induced inotropism in electrically paced (0.5 Hz, 14°C) ventricle strips at 90%Lmax (1) has a metabolic requirement for exogenous glucose and (2) is associated with enhanced intracellular Ca2+ storage and release from the sarcoplasmic reticulum (SR). We also explored whether sex differences exist in extracellular Ca2+(Ca2+o) or cardiac sensitivity to Ca2+o. In the absence or at low concentrations (1 or 2 mmol l-1) of exogenous glucose, resting tension and relaxation time were increased selectively in cardiac tissue from females. Increasing glucose promoted twitch force in a bell-shaped manner, with 5 mmol l-1representing the optimal concentration for both sexes. The positive inotropic effects of physiological concentrations of testosterone (T) and 17β-estradiol (E2) in male and female trout ventricle strips,respectively, developed slowly (10-45 min) and were not apparent in glucose-free medium, in medium containing iodoacetate (IAA), an inhibitor of glycolysis, or medium containing 5 mmol l-1 lactate or pyruvate. Male ventricle strips had increased inotropic responses to glucose and T compared with female strips exposed to glucose and E2. Furthermore, sexually maturing males showed a greater inotropic response than immature males or females. Pretreatment with ryanodine (a specific blocker of SR Ca2+release) also eliminated the inotropic effects of sex steroids and exogenous glucose and reduced the post-rest potentiation of contractile force (a marker of SR Ca2+ storage). By contrast, the inotropic effects of epinephrine (Epi) or elevated Ca2+o were faster(developing within 1-3 min) and were not diminished by the presence or absence of glucose or by pretreatment with IAA or ryanodine. Sex differences were also found in responsiveness to caffeine (males > females) and the relationship between Ca2+ concentration and force development above baseline. The Ca2+50 was lower in female cardiac tissue than males, suggesting greater Ca2+ sensitivity, and although plasma albumin was higher in females, total and ionized plasma Ca2+ did not differ between the sexes. For the first time, our study highlights the importance of extracellular glucose, glycolytic activity and SR Ca2+ storage and release for sex steroid-induced inotropism in the trout ventricle. Conversely, the inotropes Epi and elevated[Ca2+o] do not require the presence or metabolism of exogenous glucose or the SR for signaling their positive effects on contractility. These results also demonstrate novel sex-related differences in cardiac reliance on exogenous glucose, Ca2+ sensitivity and SR function and thus should be considered in future studies.
Fast-swimming hydromedusae exploit velar kinematics to form an optimal vortex wake
Authors: Dabiri John O. , Colin Sean P. , Costello John H.
Published: May 2006

Fast-swimming hydromedusan jellyfish possess a characteristic funnel-shaped velum at the exit of their oral cavity that interacts with the pulsed jets of water ejected during swimming motions. It has been previously assumed that the velum primarily serves to augment swimming thrust by constricting the ejected flow in order to produce higher jet velocities. This paper presents high-speed video and dye-flow visualizations of free-swimming Nemopsis bachei hydromedusae, which instead indicate that the time-dependent velar kinematics observed during the swimming cycle primarily serve to optimize vortices formed by the ejected water rather than to affect the speed of the ejected flow. Optimal vortex formation is favorable in fast-swimming jellyfish because,unlike the jet funnelling mechanism, it allows for the minimization of energy costs while maximizing thrust forces. However, the vortex `formation number'corresponding to optimality in N. bachei is substantially greater than the value of 4 found in previous engineering studies of pulsed jets from rigid tubes. The increased optimal vortex formation number is attributable to the transient velar kinematics exhibited by the animals. A recently developed model for instantaneous forces generated during swimming motions is implemented to demonstrate that transient velar kinematics are required in order to achieve the measured swimming trajectories. The presence of velar structures in fast-swimming jellyfish and the occurrence of similar jet-regulating mechanisms in other jet-propelled swimmers (e.g. the funnel of squid) appear to be a primary factor contributing to success of fast-swimming jetters, despite their primitive body plans.