bluuebunny/crossref_metadata_2025 huggingface dataset:
Caspase‐3 Activity and Expression of Bcl‐2 Family in Human Neutrophils by Helicobacter pylori Water‐Soluble Proteins
Authors: Kim Joo Sung , Kim Jung Mogg , Jung Hyun Chae , Song In Sung
Published: March 2003

Background.

Persistent infiltration of neutrophils is an almost invariable feature of Helicobacter pylori‐infected gastric mucosa. A prolongation of neutrophil life‐span could contribute to the pathogenesis of H. pylori infection. Recently, we have demonstrated that H. pylori water extracts (HPWE) inhibited neutrophil apoptosis. To elucidate the regulation of intracellular apoptotic signals by HPWE, we examined the activity of caspase‐8, ‐3 and expression of Bcl‐2 family in neutrophils.

Materials and methods.

Human neutrophils were obtained from the peripheral blood of healthy volunteers by density gradient separation. HPWE was prepared from a supernatant of the H. pylori suspension in distilled water. After neutrophils were incubated with HPWE, expression of Bcl‐2 family [antiapoptotic (Bcl‐2, Bcl‐XL and Mcl‐1) and proapoptotic (Bax, Bak and Bcl‐XS)] was determined by RT‐PCR and Western blotting, respectively. Western blot for Bcl‐2 family also performed in neutrophilic differentiated HL‐60 cells by all‐trans‐retinoic acid. The activity of caspase‐8, ‐3 was measured by the detection of p‐nitroanilide after cleavage from labeled substrate.

Results.

HPWE suppressed the activation of caspase‐8 and ‐3, and upregulated the expression of Bcl‐XL mRNA and proteins in neutrophils. The expression of Bax and Bak was upregulated and Bcl‐2, Bcl‐XL and Mcl‐1 downregulated in HL‐60 cells during neutrophilic differentiation.

Conclusion.

Bcl‐XL may have an important role in the neutrophilic development and inhibition of neutrophil apoptosis by H. pylori.
The Relationship Between Helicobacter pylori Infection, the Virulence Genotypes of the Infecting Strain and Gastric Cancer in the African Setting
Authors: Louw J. A. , Kidd M. S. G. , Kummer A. F. , Taylor K. , Kotze U. , Hanslo D.
Published: March 2003

Background.

The relationship between Helicobacter pylori infection and gastric carcinoma remains controversial, especially in the African setting where infection is common, while gastric cancer is perceived to be uncommon, the basis of the so called ‘African enigma’. This discrepancy between infection and the development of disease is commonly attributed to differences in host, environment and bacterial factors. Interest in the bacterial factors has focused on heterogeneity in the so‐called ‘virulence genes’.

Aim.

The aim of this prospective, case‐controlled study was to establish whether H. pylori infection is significantly associated with gastric cancer and to investigate whether gastric cancer is associated with genotypically distinct (as it relates to the candidate virulence genes) organisms in this population.

Methods.

Patients with histologically confirmed gastric cancer were matched with nonulcer dyspeptic controls for age (within 5 years), gender and ethnicity. Helicobacter pylori status was determined by RUT, histology, culture and serology (locally validated and used as default determinant of H. pylori status). Tumors were classified according to the Lauren classification. The ‘virulence genotype’ of 17 paired culture samples was determined by previously described and validated molecular techniques (cagA presence, vacA alleles, structure of the cag pathogenicity island and analysis of the iceA alleles). Categorical variables were analysed by the χ2 test.

Results.

Forty‐eight patients (median age 59 years) could be adequately matched to controls. 39/48 (81%) cases and 43/48 (90%) controls were H. pylori positive (NS). Significant differences in the virulence genotypes of infecting strains were noted: vacAs2‐controls 24%, cases 0%, p < .00001; vacAs1 present – cases 100%, controls 76%, p < .05; cagA‐3′‐length > 650 bp – cases 47%, controls 0%, p < .002; cag pathogenicity island intact – cases 82%, controls 43%, p < .04; iceA1 – cases 53%, controls 6%, p < .005. cagA was found in all subjects.

Conclusion.

This study indicates that, in this African population at least, there is no difference in the prevalence of H. pylori infection when comparing gastric cancer cases with matched controls. However, the findings suggest that gastric cancer may be associated with infection by organisms that are genotypically different from those not associated with disease.
Critical Effect of Helicobacter pylori Infection on the Effectiveness of Omeprazole for Prevention of Gastric or Duodenal Ulcers Among Chronic NSAID Users
Authors: Graham David Y.
Published: March 2003

Background. The recently reported OMNIUM and ASTRONAUT NSAID ulcer prevention trials using omeprazole to prevent endoscopic ulcer recurrence among chronic NSAID users suggested superiority over misoprostol or ranitidine.

Aim. To test the hypothesis the results from the OMNIUM and ASTRONAUT studies would not be generalizible as ulcer healing and ulcer recurrence would differ in relation to Helicobacter pylori status.

Methods. The data regarding H. pylori status were made available by AstraZenca allowing separate analysis of the outcome of those with NASID ulcers (i.e. without H. pylori infection) and those NSAID use was complicated with the presence of an active H. pylori infection.

Results. Reanalysis confirmed that omeprazole was superior to placebo for the prevention of ulcer recurrence in chronic NSAID users. However, overall omeprazole was not significantly better than the subtherapeutic dose (400 µg/day) of misoprostol (14.5% vs. 19.6%, respectively, p = .93); 400 µg of misoprostol was actually superior to omeprazole for the prevention of gastric ulcers among those NSAID ulcers (8.2% vs. 16.6% for misoprostol and omeprazole, respectively; p < .05). Omeprazole was also not statistically different from misoprostol for gastric ulcer prevention in those whose NSAID use was complicated by an active H. pylori infection. Omeprazole was not significantly different from 300 mg of ranitidine for the prevention of NSAID gastric ulcers (14.6% vs. 11.6%, respectively, p = .56). Duodenal ulcers were over represented among H. pylori infected NSAID users and duodenal ulcer prevention was more sensitive to acid suppression than gastric ulcer.

Conclusion. The OMNIUM and ASTRONAUT trials may have provided an unrealistic sense of security regarding the effectiveness of omeprazole for protection against ulcer recurrence in chronic NSAID users.
What To Do About Helicobacter pylori? A Decision Analysis of its Implication on Public Health
Authors: Sonnenberg Amnon
Published: March 2003

Objectives. Public health measures to eradicate Helicobacter pylori in the general population may prevent the occurrence of nonulcer dyspepsia (NUD), peptic ulcer (PUD) and gastric cancer, but may at the same time increase the prevalence of gastroesophageal reflux disease (GERD). A decision analysis is carried out to quantify the counteracting influences of H. pylori and resolve the controversy about a public policy to eliminate H. pylori from the general population.

Methods. A compartment model is structured to analyze the jointly beneficial and adverse effects of H. pylori. Gastric acid, H. pylori infection, and other pathophysiological mechanisms influence the occurrence of reflux disease, peptic ulcer and dyspepsia, which all contribute to the occurrence of upper abdominal symptoms. Each influence is modeled as a separate compartment with various connections to other compartments. The simulation is carried out on an electronic spreadsheet.

Results. A decision in favor or against eradication of all H. pylori depends primarily on the relative contribution of reflux disease vs. peptic ulcer and dyspepsia to upper abdominal symptoms in the general population. If reflux‐related symptoms contribute twice more than peptic ulcer plus dyspepsia to the overall occurrence of abdominal symptoms, a strategy to eradicate H. pylori would actually lower rather than raise public health. Below this threshold such strategy may improve general well‐being. In the individual patient infected with H. pylori, it remains beneficial to eradicate H. pylori, irrespective of the symptoms’ nature.

Conclusions. Although it is advisable to treat H. pylori infection in the individual patient who comes to medical attention, a general policy directed towards complete elimination of H. pylori from the population would not be beneficial. A compartment model provides a simple yet powerful method to assess complex disease behavior.
Helicobacter pylori Infection in Children and Adults: A Single Pathogen But a Different Pathology
Authors: Gallo Nicoletta , Zambon Carlo‐Federico , Navaglia Filippo , Basso Daniela , Guariso Graziella , Grazia Piva Maria , Greco Eliana , Mazza Saverio , Fogar Paola , Rugge Massimo , Di Mario Francesco , Plebani Mario
Published: March 2003

Background. The aims of this retrospective study were to ascertain in large series of children and adults: the relationship of the infecting strain to gastric mucosal lesions; and the relationship of the infecting strain to its duodenal localization.

Materials and Methods. We studied 307 and 604 consecutive children and adults. In gastric mucosal samples H. pylori was cultured, genotyped and histologically assessed, while inflammation, activity and intestinal metaplasia were graded. In a subset of 171 patients H. pylori ureaseA (ureA) and cagA genes were amplified (PCR) using mucosal biopsies from the duodenum.

Results. H. pylori infection was diagnosed in 40 children and 308 adults. cagA was identified in 50% and 65.5% of infected children and adults. Antral activity was associated with the density of infecting bacteria (p < .001) and with cagA (p < .01). Intestinal metaplasia was correlated with cagA (p < .001). The ureA gene was found in 56 duodenal samples from 82 H. pylori positive patients. Duodenal H. pylori ureA was significantly more frequent in patients with duodenal diseases than in those without (p < .01), cagA positive strains being mainly involved in the infection of this anatomical area (p < .01).

Conclusions. A severe H. pylori‐associated gastritis is more prevalent when the density of infecting bacteria is high and when cagA positive strains cause the infection. The most virulent cagA positive H. pylori colonizes not only the gastric, but also the duodenal mucosa, which can be directly damaged by the bacteria itself or by its products.
Occupational Exposure to Human Immunodeficiency Virus: What Healthcare Providers Should Know
Authors: Aboulafia David M.
Published: March 2003

PURPOSE
: The author reviews the risks of occupational exposure to HIV and provides a rationale for new postexposure guidelines for healthcare workers.

OVERVIEW
: Approximately 50,000 percutaneous exposures occur yearly among healthcare workers in the United States. Of these, approximately 5000 involve exposures to blood that is known to be infected with HIV. The risk of transmission after percutaneous exposure to HIV‐tainted blood has been estimated to be 0.3%, but the risk may be considerably higher to the healthcare worker if any of the following is present: a deep injury; visible blood on the sharp device; a procedure that involves a needle placed in the patient's artery or vein; and a patient with advanced AIDS. The increasing resistance of HIV strains to antiretroviral therapy continues to make treatment more difficult.

CLINICAL IMPLICATIONS
: Postexposure prophylaxis with zidovudine may reduce the risk of occupational infection by 80%. Advances in the ability to ameliorate HIV transmission rates and to treat individuals with resistant disease through innovations in drug therapy, engineering of controls for injury prevention, and more focused postexposure evaluation offer the hope of reducing this infrequent, but dangerous, occupational threat.
The informational needs of patients with cancer and their families.
Authors: Harris KA
Published: March 2003

PURPOSE: Seven years ago, the National Cancer Institute compiled a review of the literature published from 1979 to 1990 on information, education, and communication needs of patients with cancer and their families. Because of its potential value to health professionals and to the community, an updated report of relevant literature is presented in this article. The report provides analysis to assist health professionals in tailoring the quantity, variety, and timing of information they present to the patient with cancer and his or her family. OVERVIEW: This review incorporates a sample of 66 articles published from 1990 to 1997. Of these 44 articles address the information, education, and communication needs of patients with cancer and their families. The discussion focuses on how health professionals can maximize patient comprehension and retention of information, encourage patient participation in health decision making, and foster dialogue with patients and families. CLINICAL IMPLICATIONS: Steps should be taken within healthcare organizations to ensure that ongoing informational needs assessment and education are a routine part of comprehensive cancer patient care. This analysis points to the importance of tailoring information to meet patients' educational background, cultural orientation, and general level of comprehension. Healthcare providers must not only consider the degree to which a patient with cancer desires information, but also how active a role he or she wishes to take in making treatment decisions. In addition, health professionals should be aware that the informational needs of patients and family members change throughout the course of care and therefore should be reassessed periodically.
Cancer Self‐Help Groups and Family Physicians
Authors: Gray Ross E. , Carroll June C. , Fitch Margaret , Greenberg Marlene , Chart Pamela , Orr Vanessa
Published: March 2003

PURPOSE
: Despite the phenomenal growth during the past decade of cancer self‐help groups for adult patients with cancer, little research has been conducted to document the interface between these groups and healthcare professionals, especially physicians. This study was initiated to provide information about family physician practices, awareness, and attitudes about self‐help groups.

DESCRIPTION
: A survey questionnaire was mailed to a random sample of Ontario family physicians drawn from the College of Family Physicians of Canada's membership database.

RESULTS
: A total of 911 completed questionnaires were returned, for a response rate of 64%. A majority (56.8%) of respondents were aware of at least one cancer self‐help group in their region; 26.8% of these spoke frequently with their cancer patients about such groups. Most family physicians indicated that they were positively inclined toward cancer self‐help groups, giving especially high ratings of helpfulness to sharing common experiences, overcoming isolation, feeling understood, and sharing information. Ratings of potential harm were low, with the most concern expressed about the possible provision of misinformation and the promotion of unconventional therapies. Responses to an open‐ended question showed that many family physicians qualify their support for cancer self‐help groups, depending on patient need, group composition, and leadership.

CLINICAL IMPLICATIONS
: Family physicians and other members of the cancer care team should give increased attention to informing cancer patients about the potential benefits of self‐help groups. Efforts need to be made to assist cancer self‐help groups in developing informational brochures and to ensure that groups are listed in cancer resource directories. Educational initiatives about self‐help groups would be useful for family physicians and other health professionals engaged in the care of cancer patients.
Limited Literacy Revisited Implications for Patient Education
Authors: Foltz Ann T. , Sullivan Joan M.
Published: March 2003

purpose
: It is important to determine whether teaching materials are understood and deemed accurate by the cancer patients being served. The authors used a series of patient participatory interviews to evaluate two brochures: Chemotherapy: What It Is and How It Helps by the American Cancer Society; and Helping Yourself During Chemotherapy: 4 Steps for Patients by the National Cancer Institute. The authors sought to determine whether 1) the brochures were clear; 2) differences in presentation were perceived by patients; and 3) differences influenced respondents' understanding and opinions of the brochures.

description of study
: A qualitative, focus‐group methodology was used. Twelve cancer patients, eight of whom were women and six of whom were African American, were recruited from three outpatient clinics. Participants ranged in age from 31 to 62 years of age, and in education from completion of ninth grade to graduate school. Patients participated in a series of five groups, with a series of semistructured questions about content and format being asked of each group. All sessions were audiotaped. The investigators reviewed data both independently and together to identify content and format evaluations.

results
: Findings showed that most participants were drawn first by the National Cancer Institute format; the American Cancer Society brochure was seen as having more information; the two brochures were seen as complementary; some confusion arose from the content of both brochures; and the discussions of emotional and sexual aspects were important.

clinical implications
: These findings support the need for simple, clearly written brochures rather than brochures of varying literacy levels. The confusion caused by differences in advice given by the two organizations indicates the need to address specific areas in which dissimilarities exist. Finally, the project demonstrates the utility of patient focus groups for evaluation of patient education material.
Complementary Therapy Use Among Older Cancer Patients
Authors: Wyatt Gwen K. , Friedman Laurie L. , Given Charles W. , Given Barbara A. , Beckrow Kathryn Christensen
Published: March 2003

purpose
: The purpose of this study was to assess the use of complementary therapies among older cancer patients, to report patterns of use, and to understand who is more likely to use complementary therapies.

description of study
: A survey was conducted of 699 older cancer patients at 4 weeks and 6 weeks into cancer treatment. All participants were 64 years of age or older, had received a diagnosis of breast, colorectal, prostate, or lung cancer, and were recruited from community cancer treatment centers throughout Michigan. Measures of interest included self‐reported physical symptoms, depressive symptomatology, optimism, spirituality, and use of conventional and complementary health services.

results
: Approximately 33% of older cancer patients reported using complementary therapies. These individuals were more likely to be women, to be breast cancer patients, and to have a higher level of education. The three most frequently used therapies were exercise, herbal therapy, and spiritual healing. Complementary therapy users were significantly more optimistic than nonusers. Also, there were significant differences between users and nonusers on types of physical symptoms experienced, but no differences on reported depressive symptomatology or spirituality.

clinical implications
: Oncology providers need to be aware that one third of their older patients are likely to supplement conventional care with complementary therapies. Therefore, providers should be knowledgeable about the safety and efficacy, in particular, of various exercise programs, herbal and vitamin therapies, and spiritual healing. It would be beneficial to develop a system within cancer centers by which patients could easily report on their use of complementary therapies, allowing providers to work in partnership with their patients.
Feasibility of Assessing Quality in Medical Oncology Practices
Authors: Cornfeld Mark J. , Jadwin Anne , O'Grady Peg , Babb Jim , Engstrom Paul F.
Published: March 2003

Purpose: This study was designed to test the feasibility of conducting routine quality assessment within community medical oncology practices.

Description of study: Eleven medical oncologists practicing within the Fox Chase Network were surveyed over an 8‐month period, using a standardized 10‐item checklist. Eight of the items (ie, board certification, continuing education, office procedure manual for chemotherapy, chemotherapy flow sheets, body surface area calculations, adherence to guidelines for follow‐up of breast cancer, adjuvant hormones in women with estrogen receptor‐positive breast cancer, and patient satisfaction survey) were chosen because they measure structural and process variables particularly relevant to the high‐volume clinical services seen in private practice oncology. The authors also calculated two rates (protocol accrual and neutropenic complications of chemotherapy) to test as putative indicators of quality.

Results: The authors found a high level of both physician interest in developing the audit measures and compliance with the survey process. Overall quality of care, as measured by structure and process variables, was excellent with negligible internal variability. Derived rates of protocol accrual (0.003–0.373; mean 0.11, SD 0.11) and neutropenic sepsis (0.004–0.014; mean 0.007, SD 0.004) show considerable variability, however, and are only minimally correlated (r = −.36). These are both potential indicators of quality that should be further evaluated.

Clinical implications: The authors have demonstrated the feasibility of conducting quality assessment within private medical oncology practices and have identified two easily calculated rates that merit further study as potential indicators of quality.
Community Implementation of Home Care Palliative Care Education
Authors: Ferrell Betty R. , Borneman Tami
Published: March 2003

purpose: The purpose of this National Cancer Institute‐funded training project was to improve end‐of‐life care agencies through implementation of a palliative care curriculum. The Home Care Outreach for Palliative Care Education (HOPE) program was designed to improve the knowledge and skills of home healthcare professionals who provide care to the terminally ill and their families at home.

description of program: A five‐module palliative care education curriculum was designed and implemented in five home care agencies in the Los Angeles area. One hundred twenty‐five nurses and 28 home health aides participated. The methods of data collection included two written surveys conducted before and after intervention, chart audit tool and a case study analysis form.

results: The precourse data revealed deficiencies in home‐care agency staff knowledge in and clinical aspects of end‐of‐life care. Regarding agency nurses' knowledge on end‐of‐life issues, the overall percentage scores from preeducation to posteducation rose from 84.6% to 89.0% (P = .0001). Participants rated the education program as extremely valuable for the home care agency staff.

clinical implications: As home care will likely continue to be a primary setting for end‐of‐life healthcare, improvement of palliative care education in home health agencies is needed. The HOPE project provided insight and experience in the education of nonhospice home care staff in end‐of‐life care. Participant responses and evaluations indicated that end‐of‐life care education can improve the quality of care provided by home health agencies. Finally, this education program may result in a heightened awareness of hospice care and, although not objectively quantified, perhaps an increase in referrals to hospice.
Online Cancer Patient Education
Authors: Cumbo Angelique , Agre Patricia , Dougherty James , Callery Matt , Tetzlaff Linda , Pirone Jane , Tallia Rob
Published: March 2003

purpose: Two patient education CD‐ROMs were converted to a web‐based environment. This article reports on users' evaluations of the programs' usability and content.

description of evaluation: Subscribers to a center's web newsletter were asked to view one of two web programs and to complete a survey. The first 150 respondents were offered a free patient education CD‐ROM of their choice, but users continued to respond to the survey even after a notice stated that 150 responses were received. A total of 301 surveys were completed (Colorectal Cancer Program 168; Chemotherapy Program 133).

results: Sixty‐eight percent of Colorectal Cancer Program respondents and 50% of Chemotherapy Program respondents considered the program to be more useful or much more useful than any other source of information on the topic. A majority of users for both programs preferred to view the information on the Internet rather than on CD‐ROM. Many users reported trouble accessing certain segments of the media. Common complaints included the inability to open video or audio clips and the length of time needed for each page to load, despite a high‐speed Internet connection.

clinical implications: Internet use is high, with 60% of US households reporting having used the Internet to search for health information. However, little is known about user satisfaction with specific sites and what about them users like or do not like. It is hoped that these and other user evaluations will help web site authors and developers improve their sites.
Promoting Fecal Occult Blood Testing in Rural African American Women
Authors: Powe Barbara D.
Published: March 2003

purpose: The purpose of this experimental study was to test the effectiveness of a multiphasic culturally relevant intervention, delivered over a 1‐year period to increase the rates of participation in fecal occult blood testing (FOBT) at the initial screening opportunity and at the 1‐year follow‐up screening opportunity among rural African American women.

description of study: The study used a pretest/post‐test design among African American women who attended senior citizen centers in a rural southern state. The centers were randomly assigned to the cultural and self‐empowerment group, who received the five‐phased intervention, the modified cultural group, who received phase I of the intervention only, or the traditional group, who served as the control group. Data were collected at the initial and 1‐year follow‐up screenings. Hemoccult kits were distributed, collected, and analyzed at no cost to the participants. Data were analyzed using descriptive statistics, repeated measures, and longitudinal models for binary outcomes.

results: Women in the cultural and self‐empowerment group had a significantly higher rate of participation in FOBT than did those in the modified cultural group and the traditional group. The modified cultural group had a significantly higher rate of participation in FOBT than the did the traditional group. Predictors of participation in FOBT were the women's family history of colorectal cancer and the average number of visits to their healthcare provider.

clinical implications: Colorectal cancer screening and diagnostic testing opportunities should be offered consistently to women who visit their provider for routine, nonemergent office visits. As successful interventions to increase colorectal cancer screening are introduced into community settings, these interventions also should be tested within physicians' offices and other community agencies.
Mucosal Tissue Injury in Cancer Therapy
Authors: McGuire Deborah B.
Published: March 2003

purpose: The purpose of this article is as follows: 1) to describe the characteristics and scope of mucosal tissue injury associated with cancer treatment; 2) to discuss recent advances in related basic and clinical science; and 3) to articulate research needs and opportunities to be addressed through collaborative interdisciplinary research.

overview: Mucosal tissue injury is both a direct and indirect consequence of cancer therapy, with manifestations that include damage and a number of other potentially serious sequelae. Current research in mucosal tissue injury is focused on the biology, immunology, and genetics of mucosal injury; clinical problems; assessment and management; and processes and outcomes of care.

clinical implications: Results from these various areas of research enhance the understanding of the mechanisms of mucosal tissue injury, provide direction for the development of policy and for clinical practice, and help to define research needs and opportunities. Future research on the complex process of mucosal tissue injury will be interdisciplinary and will cross the boundaries among basic, translational, and clinical science.
Novel gene expression patterns in hybrid embryos between species with different modes of development
Authors: Nielsen Mark G. , Wilson Keen A. , Raff Elizabeth C. , Raff Rudolf A.
Published: March 2003

SUMMARY Cross‐species hybrids between eggs of the direct‐developing sea urchin, Heliocidaris erythrogramma, and sperm from its congeneric indirect‐developing species, Heliocidaris tuberculata, show restoration of features of the paternal feeding pluteus larva, including the gut, and pluteus spicular skeleton. Unlike other reported sea urchin cross‐species hybrids, Heliocidaris hybrids express genes derived from both maternal and paternal species at high levels. Ectodermal cell types, which differ radically between the two parental species, are of intermediate form in the hybrids. Gene expression patterns in hybrid embryo tissues represent a number of combinations of parental gene expression patterns: genes that are not expressed in one paternal species, but are expressed in hybrids as in the expressing parent; genes that show additive expression patterns plus novel sites of expression; a gene that is misexpressed in the hybrids; and genes expressed identically in both parents and in hybrids. The results indicate that both conserved and novel gene regulatory interactions are present. Only one gene, CyIII actin, has lost cell‐type‐specific regulation in the hybrids. Hybrids thus reveal that disparate parental genomes, each with its own genic regulatory system, can produce in combination a novel gene expression entity with a unique ontogeny. This outcome may derive from conserved gene regulatory regions in downstream genes of both parental species responding in conserved ways to higher‐level regulators that determine modular gene expression territories.
Adaptation and constraint in the evolution of Drosophila melanogaster wing shape
Authors: Gilchrist A. S. , Azevedo R. B. R. , Partridge L. , O'higgins P.
Published: March 2003

SUMMARY We have taken advantage of parallel instances of natural selection on body size in Drosophila melanogaster to investigate constraints and adaptation affecting wing shape. Using recently developed techniques for statistical shape analysis, we have examined variation in wing shape in similar body size clines on three continents. Gender‐related shape differences were constant among all populations, suggesting that gender differences represent a developmental constraint on wing shape. In contrast, the underlying shape varied significantly between continents and shape change within each cline (i.e., between small and large body size populations) also varied between continents. Therefore, variation at these two levels presumably results from either drift or natural selection. Functional considerations suggest that shape variation between the continents is unlikely to be adaptive. However, cline‐related shape change, which we show has a significant allometric component, may be adaptive. The overall range of wing shape variation, across a large range of wing size, is extremely small, and the possibility that wing shape is subject to stabilizing selection (or canalization) is discussed.
The significance of moulting in Ecdysozoan evolution
Authors: Valentine James W. , Collins Allen G.
Published: March 2003

SUMMARY Three major bilaterian clades first appear in the Early Cambrian fossil record: Deuterostomia, Lophotrochozoa, and Ecdysozoa. The taxa placed in Ecdysozoa are characterized by a moulting habit, unknown in the other major clades. The origin and consequences of moulting are of fundamental importance to the history of the ecdysozoan clade, chiefly because moulting precludes motile ectodermal cilia. Moulting may have originated as an adaptation to permit the enlargement, during growth, of secreted cuticular spines, flanges, and other structures used as ancillary locomotory devices. A combination of phylogenetic and fossil evidence suggests that the early members of these clades were small vermiform paracoelomates that likely lacked indirect‐developing planktotrophic larvae. Thus, the evolution of planktotrophic larvae may have been independently achieved at least three times within Bilateria. The nonmoulting clades evolved larvae that swim and feed via ciliated tufts and bands, presumably intercalating these forms within their early developmental systems. Within Ecdysozoa, feeding larvae lacked ciliary feeding tracts and evolved by modification of early instars, employing limbs or setae to generate feeding currents. The setting aside during larval life of cells that give rise to adult features is probably an adaptation associated with metamorphosis.
Developmental constraints on an adaptive plasticity: reaction norms of pigmentation in adult segments of Drosophila melanogaster
Authors: Gibert Patricia , Moreteau Brigitte , David Jean R.
Published: March 2003

SUMMARY Variation of dark pigmentation according to developmental temperature was investigated in two geographic populations (France and India) with the isofemale line technique (20 lines for each population). The response curves called the reaction norms, were established in females for seven different segments: the mesothorax and abdomen segments 2–7 (Abd 2–7). In all cases the response curves were non‐linear and had to be described either by a quadratic convex polynomial for thorax and Abd 2–5, or by a cubic polynomial for Abd 6 and 7. Among abdomen segments, increasing antero‐posterior gradients were observed for several traits, including average pigmentation, overall phenotypic plasticity, the temperature of minimum pigmentation, and the curvature parameter of quadratic norms. Genetic correlations between abdomen segments were high when adjacent segments were considered, but became nil when more distant segments were correlated, suggesting that different pigmentation genes are expressed in the anterior and the posterior part of the abdomen. Characteristic values of reaction norms provided information either on trait value (i.e., the extension of pigmentation) or on plasticity. Correlations between plasticity and pigmentation were generally low and non‐significant, suggesting their genetic independence. The overall darker pigmentation which is observed at low temperatures is assumed to be an adaptive plasticity. However, the differences which are evidenced among segments reveal strong interactions with developmental genes. These interactions are less likely to be a consequence of natural selection and are better interpreted as developmental constraints. The reaction norms analysis reveals the complexity of these interactions and should help, in the future, in the identification of the responsible thermosensitive genes.
Teeth outside the mouth in teleost fishes: how to benefit from a developmental accident
Authors: Sire Jean‐Yves
Published: March 2003

SUMMARY Evolution proceeds by the selection of characters that enhance survival rates so that the long‐term outcome for a species is better adaptation to its environment. These new characters are “accidentally” acquired, mostly through mutations leading to modifications of developmental events. However, changes that lead to the ectopic expression of an organ are rare and, whereas their subsequent selection for a new role is even more rare, such a scenario has apparently occurred for denticles in some teleost fish. Small, conical denticles are present, mainly on the dermal bones of the head, in a few, unrelated lineages of living teleosts. Here, I show that the morphology and structure of the denticles in Atherion elymus, an atheriniform, is similar to those of teeth inside the oral cavity. These denticles are not derived evolutionarily from odontodes of early vertebrates, nor do they represent a re‐expression as such (i.e., a long‐lasting ability to make odontodes outside the oral cavity). Teeth and odontodes are homologous organs but the origin of the denticles is to be found in teeth, not in odontodes. The denticles are simply teeth that form outside the mouth, probably derived from a sub‐population of odontogenically pre‐specified neural crest cells. These “accidental” extra‐oral teeth have arisen independently in these lineages and were selectively advantageous in a hydrodynamic context.
Why are arthropods segmented?
Authors: Budd Graham E.
Published: March 2003

SUMMARY Segmentation as an attribute of organisms is being increasingly discussed in the recent literature because (1) new phylogenies suggest that organisms classically considered to be segmented may lie in separate clades; (2) the molecular basis of segmental development has been much studied; (3) various theories of bilaterian origins place weight on segmentation as a primitive character; (4) there has been recent stress on the importance of modularity as an evolutionary topic. However, the definition and extent of segmentation are highly ambiguous and usually typological. Here, segmentation is regarded as an attribute of organs, not organisms. The evolution of just one system, the arthropod epidermis, is examined on the basis of the fossil record and the extant euarthropods, tardigrades, and onychophorans. It may be seen to have become segmented in a complex pathway that necessitated shifts in function, redundancy, and changes in associated organs. This complexity must inevitably reflect on, and to an extent have primacy over, the genetic basis for the changes involved. Evolutionary functional morphology has been relatively little considered in the context of the evolution of development, but may play an important role in defining the framework within which this evolution occurs.
Defining phyla: evolutionary pathways to metazoan body plans
Authors: Collins Allen G. , Valentine James W.
Published: March 2003

SUMMARY Phyla are defined by two sets of criteria, one morphological and the other historical. Molecular evidence permits the grouping of animals into clades and suggests that some groups widely recognized as phyla are paraphyletic, while some may be polyphyletic; the phyletic status of crown phyla is tabulated. Four recent evolutionary scenarios for the origins of metazoan phyla and of supraphyletic clades are assessed in the light of a molecular phylogeny: the trochaea hypothesis of Nielsen; the clonal hypothesis of Dewel; the set‐aside cell hypothesis of Davidson et al.; and a benthic hypothesis suggested by the fossil record. It is concluded that a benthic radiation of animals could have supplied the ancestral lineages of all but a few phyla, is consistent with molecular evidence, accords well with fossil evidence, and accounts for some of the difficulties in phylogenetic analyses of phyla based on morphological criteria.
Conservation and variation in Ubx expression among chelicerates
Authors: Popadić Aleksandar , Nagy Lisa
Published: March 2003

SUMMARY Chelicerates are an ancient arthropod group with a distinct body plan composed of an anterior (prosoma) and a posterior portion (opisthosoma). The expression of the Hox gene Ultrabithorax (Ubx) has been examined in a single representative of the chelicerates, the spider Cupiennius salei. In spiders, Ubx expression starts in the second opisthosomal segment (O2). Because the first opisthosomal segment (O1) in spiders is greatly reduced relative to other chelicerates, we hypothesized that the observed Ubx expression pattern might be secondarily modified. Shifts in the anterior boundary of the expression of Ubx have been correlated with functional shifts in morphology within malacostracan crustaceans. Thus, the boundary of Ubx expression between chelicerates with different morphologies in their anterior opisthosoma could also be variable. To test this prediction, we examined the expression patterns of Ubx and abdominal‐A (collectively referred to as UbdA) in two basal chelicerate lineages, scorpions and xiphosurans (horseshoe crabs), which exhibit variation in the morphology of their anterior opisthosoma. In the scorpion Paruroctonus mesaensis, the anterior border of early expression of UbdA is in a few cells in the medial, posterior region of the O2 segment, with a predominant expression in O3 and posterior. Expression later spreads to encompass the whole O2 segment and a ventral, posterior portion of the O1 segment. In the xiphosuran Limulus polyphemus, early expression of UbdA has an anterior boundary in the segment. Later in development, the anterior boundary moves forward one segment to the chilarial (O1) segment. Thus, the earliest expression boundary of UbdA lies within the second opisthosomal segment in all the chelicerates examined. These results suggest that rather than being derived, the spider UbdA expression in O2 likely reflects the ancestral expression boundary. Changes in the morphology of the first opisthosomal segment are either not associated with changes in UbdA expression or correlate with late developmental changes in UbdA expression.
Structure and metamorphic remodeling of the larval nervous system and musculature of Phoronis pallida (Phoronida)
Authors: Santagata Scott
Published: March 2003

SUMMARY The structure of the larval nervous system and the musculature of Phoronis pallida were studied, as well as the remodeling of these systems at metamorphosis. The serotonergic portion of the apical ganglion is a U‐shaped field of cell bodies that send projections into a central neuropil. The majority of the serotonergic cells are (at least) bipolar sensory cells, and a few are nonsensory cells. Catecholaminergic cell bodies border the apical ganglion. The second (hood) sense organ develops at competence and is composed of bipolar sensory cells that send projections into a secondary neuropil. Musculature of the competent larva includes circular and longitudinal muscle fibers of the body wall, as well as elevators and depressors of the tentacles and hood. The juvenile nervous system and musculature are developed prior to metamorphosis and are integrated with those of the larva. Components of the juvenile nervous system include a diffuse neural net of serotonergic cell bodies and fibers and longitudinal catecholaminergic fibers. The juvenile body wall musculature consists of longitudinal fibers that overlie circular muscle fibers, except in the cincture regions, where this pattern is reversed. Metamorphosis is initiated by the larval neuromuscular system but is completed by the juvenile neuromuscular system. During metamorphosis, the larval nervous system and the musculature undergo cell death, and the larval tentacles and gut are remodeled into the juvenile arrangement. Although the phoronid nervous system has often been described as deuterostome‐like, these data show that several cytological aspects of the larval and juvenile neuromuscular systems also have protostome (lophotrochozoan) characteristics.
Brachyury expression in tailless Molgulid ascidian embryos
Authors: Takada Norio , York Jonathan , Davis J. Muse , Schumpert Brenda , Yasuo Hitoyoshi , Satoh Nori , Swalla Billie J.
Published: March 2003

SUMMARY The T‐box transcription factor gene Brachyury is important for the differentiation of notochord in all chordates, including the ascidians Halocynthia roretzi and Ciona intestinalis. We isolated Brachyury from molgulid ascidians, which have evolved tailless larvae multiple times independently, and found the genes appear functional by cDNA sequence analyses. We then compared the expression of Mocu‐Bra in tailed Molgula oculata embryos to two tailless species, Molgula occulta (Mocc‐Bra) and Molgula tectiformis (Mt‐Bra). Here we show that both tailless species express Brachyury in the notochord lineage during embryogenesis. Initial expression of Mocu‐Bra is normal in tailed M. oculata embryos; 10 precursor notochord cells divide twice to result in 40 notochord cells that converge and extend to make a notochord down the center of the tail. In contrast, in tailless Molgula occulta, Mocc‐Bra expression disappears prematurely, and there is only one round of division, resulting in 20 cells in the final notochord lineage that never converge or extend. In M. occulta×M. oculata hybrid embryos, expression of Mocu‐Bra is prolonged, and the embryos form a tail with 20 notochord cells that converge and extend normally. However, in Molgula tectiformis, a different tailless ascidian, Mt‐Bra was expressed only in the 10 notochord precursor cells, which never divide, converge, or extend. In summary, neither Brachyury function nor the early establishment of the notochord lineage appears to be impaired in tailless embryos. In light of these results, we are continuing to investigate how and why notochord development is lost in tailless molgulid ascidian embryos.
Expression of the Artemia trachealess gene in the salt gland and epipod
Authors: Mitchell Brian , Crews Stephen T.
Published: March 2003

SUMMARY The Drosophila trachealess gene encodes a basic‐helix‐loop‐helix‐PAS transcription factor that controls the formation of the trachea and salivary duct. An ortholog of trachealess was identified in the brine shrimp, Artemia franciscana, and was shown to be highly conserved by sequence identity. Expression of Artemia trachealess was observed at two sites during development: the naupliar salt gland and the juvenile thoracic epipod. These two organs function at their respective times of development in osmoregulation, an important aspect of brine shrimp physiology. This extends the range of putative functions of trachealess to include formation of osmoregulatory, respiratory, and ductile organs.
A novel amphioxus cadherin that localizes to epithelial adherens junctions has an unusual domain organization with implications for chordate phylogeny
Authors: Oda Hiroki , Wada Hiroshi , Tagawa Kunifumi , Akiyama‐Oda Yasuko , Satoh Nori , Humphreys Tom , Zhang Shicui , Tsukita Shoichiro
Published: March 2003

SUMMARY Although data are available from only vertebrates, urochordates, and three nonchordate animals, there are definite differences in the structures of classic cadherins between vertebrates plus urochordates and nonchordates. In this study we examined structural diversity of classic cadherins among bilaterian animals by obtaining new data from an amphioxus (Cephalochordata, Chordata), an acorn worm (Hemichordata), a sea star (Echinodermata), and an oyster (Mollusca). The structures of newly identified nonchordate cadherins are grouped together with those of the known sea urchin and Drosophila cadherins, whereas the structure of an amphioxus (Branchiostoma belcheri) cadherin, designated BbC, is differently categorized from those of other known chordate cadherins. BbC is identified as a cadherin by its cytoplasmic domain whose sequence is highly related to the cytoplasmic sequences of all known classic cadherins, but it lacks all of the five repeats constituting the extracellular homophilic‐binding domain of other chordate cadherins. The ectodomains of BbC match the ectodomains found in nonchordate cadherins but not present in other chordate cadherins. We show that the BbC functions as a cell–cell adhesion molecule when expressed in Drosophila S2 cells and localizes to adherens junctions in the ectodermal epithelia in amphioxus embryos. We argue that BbC is the amphioxus homologue of the classic cadherins involved in the formation of epithelial adherens junctions. The structural relationships of the cadherin molecules allow us to propose a possibility that cephalochordates might be basal to the sister‐groups vertebrates and urochordates.