bluuebunny/crossref_metadata_2025 huggingface dataset:
Are non-responders in a quitline evaluation more likely to be smokers?
Authors: Tomson Tanja , Björnström Catrine , Gilljam Hans , Helgason Asgeir
Published: May 2005

Background

In evaluation of smoking cessation programs including surveys and clinical trials the tradition has been to treat non-responders as smokers. The aim of this paper is to assess smoking behaviour of non-responders in an evaluation of the Swedish national tobacco cessation quitline a nation-wide, free of charge service.

Methods

A telephone interview survey with a sample of people not participating in the original follow-up. The study population comprised callers to the Swedish quitline who had consented to participate in a 12 month follow-up but had failed to respond. A sample of 84 (18% of all non-responders) was included. The main outcome measures were self-reported smoking behaviour at the time of the interview and at the time of the routine follow-up. Also, reasons for not responding to the original follow-up questionnaire were assessed. For statistical comparison between groups we used Fischer's exact test, odds ratios (OR) and 95% confidence intervals (CI) on proportions and OR.

Results

Thirty-nine percent reported to have been smoke-free at the time they received the original questionnaire compared with 31% of responders in the original study population. The two most common reasons stated for not having returned the original questionnaire was claiming that they had returned it (35%) and that they had not received the questionnaire (20%). Non-responders were somewhat younger and were to a higher degree smoke-free when they first called the quitline.

Conclusion

Treating non-responders as smokers in smoking cessation research may underestimate the true effect of cessation treatment.
New chemolysis for urological calcium phosphate calculi – a study in vitro
Authors: Xiang-bo Zhang , Zhi-ping Wang , Jian-min Duan , Jian-zhong Lu , Bao-liang Ma
Published: May 2005

Background

Advances in techniques have left very few indications for open surgical extraction of urinary stones currently. These advances notwithstanding, the search continues for medical approaches to urinary stone management. In this study, we perform an in vitro study analyzing the efficiency and prospect of two new complex solutions in urological calcium phosphate calculi dissolution.

Methods

Eighteen stones composed mainly of calcium phosphates were taken from patients who underwent kidney stone surgery. These stones were large enough (weight range 0.514–0.928 g) to be fragmented and matched equally into six groups. Chemolysis of phosphate stones was done with six different solvents and was repeated 3 times with 6 stones for each solution. At 24, 48 and 72 h, reduction in weight, percentage weight change, and dissolution rate; the dissolution rates at pH 5.0, 7.0 and 8.5 for each solution, using different cations (Na+, K+ or Ca2+), according to different dilutions (1:1, 1:2, 1:3, 1:4) of S1 and S2 were simultaneously determined.

Results

Calcium phosphate calculi were poorly dissolved by Phys and Art, and they had a low dissolution rate in pH 8.5 EDTA. The most effective solutions were S1, S2 and R, with 72 h mean dissolution rates: 5.75 ± 0.44 mg/hr (S1), 5.2 ± 0.63 mg/hr (S2), 4.55 ± 0.46 mg/hr (R) ("Equation missing" ± s, p < 0.01 R, S1 and S2 vs Phys, Art and EDTA; p < 0.05, S1 vs R, LSD-test). The mean percentage weight loss at 72 h was: 52.1 ± 15.75 % (S1), 44.4 ± 7.37 % (S2) and 40.5 ± 3.67 % (R) ("Equation missing" ± s, p < 0.01 R, S1 and S2 vs Phys, Art and EDTA, LSD-test). Diluted twice, S1 and S2 had even better effectiveness than their initial solution. The additive of Na+, K+ or Ca2+ greatly reduced the dissolution rates of S1, S2.

Conclusion

Our data indicate that test solutions S1 and S2 are effective solvents in the chemolysis of calcium phosphate stones. At twice dilutions, these solutions are even more useful in the treatment of stone disease.
Simultaneous imaging of GFP, CFP and collagen in tumors in vivousing multiphoton microscopy
Authors: Sahai Erik , Wyckoff Jeffrey , Philippar Ulrike , Segall Jeffrey E , Gertler Frank , Condeelis John
Published: May 2005

Background

The development of multiphoton laser scanning microscopy has greatly facilitated the imaging of living tissues. However, the use of genetically encoded fluorescent proteins to distinguish different cell types in living animals has not been described at single cell resolution using multiphoton microscopy.

Results

Here we describe a method for the simultaneous imaging, by multiphoton microscopy, of Green Fluorescent Protein, Cyan Fluorescent Protein and collagen in vivo in living tumors. This novel method enables: 1) the simultaneous visualization of overall cell shape and sub-cellular structures such as the plasma membrane or proteins of interest in cells inside living animals, 2) direct comparison of the behavior of single cells from different cell lines in the same microenvironment in vivo.

Conclusion

Using this multi-fluor, multiphoton technique, we demonstrate that motility and metastatic differences between carcinoma cells of differing metastatic potential can be imaged in the same animal simultaneously at sub-cellular resolution.
A centralised public information resource for randomised trials: a scoping study to explore desirability and feasibility
Authors: Langston Anne L , Campbell Marion K , Entwistle Vikki A , Skea Zoë
Published: May 2005

Background

There are currently several concerns about the ways in which people are recruited to participate in randomised controlled trials, the low acceptance rates among people invited to participate, and the experiences of trial participants. An information resource about on-going clinical trials designed for potential and current participants could help overcome some of these problems.

Methods

We carried out a scoping exercise to explore the desirability and feasibility of establishing such a resource. We sought the views of a range of people including people who were considering taking part in a trial, current trial participants, people who had been asked but refused to participate in a trial, consumer group representatives and researchers who design and conduct trials.

Results

There was broad-based support for the concept of a centralised information resource for members of the public about on-going and recently completed clinical trials. Such an information resource could be based on a database containing standardised information for each trial relating to the purpose of the trial; the interventions being compared; the implications of participation for participants; and features indicative of scientific quality and ethical probity. The usefulness of the database could be enhanced if its search facility could allow people to enter criteria such as a disease and geographic area and be presented with all the trials relevant to them, and if optional display formats could allow them to view information in varying levels of detail. Access via the Internet was considered desirable, with complementary supported access via health information services. The development of such a resource is technically feasible, but the collation of the required information would take a significant investment of resources.

Conclusion

A centralised participant oriented information resource about clinical trials could serve several purposes. A more detailed investigation of its feasibility and exploration of its potential impacts are required.
Gastric extremely well differentiated adenocarcinoma of gastric phenotype: as a gastric counterpart of adenoma malignum of the uterine cervix
Authors: Ae Lee Won
Published: May 2005

Background

Most of gastric adenocarcinoma can be simply diagnosed by microscopic examination of biopsy specimen. Rarely the structural and cellular atypia of tumor cells is too insignificant to discriminate from benign foveolar epithelium.

Case presentation

A 67-year-old male presented with a gastric mass incidentally found on the abdominal computed tomography (CT) for routine medical examination. Gastric endoscopic examination revealed a huge fungating mass at the cardia and mucosal biopsy was performed. Microscopically the biopsy specimen showed proliferation of bland looking foveolar epithelia in the inflammatory background and diagnosed as foveolar epithelial hyperplasia. Because the clinical and endoscopic features of this patient were strongly suggestive of malignancy, the patient underwent radical total gastrectomy. The resected stomach revealed a huge fungating tumor at the cardia. The cut surface of the tumor was whitish gelatinous. Microscopically the tumor was sharply demarcated from surrounding mucosa and composed of very well formed glandular structures without significant cellular atypia, which invaded into the whole layer of the gastric wall. Tumor glands were occasionally complicated or dilated, and glandular lumina were filled with abundant mucin. Immunohistochemically the tumor cells revealed no overexpression of p53 protein but high Ki-67 labeling index. The tumor cells and intraluminal mucin were diffusely expressed MUC1 and MUC5AC and only focally expressed MUC2. On abdominal CT taken after 12 months demonstrated peritoneal carcinomatosis and multiple metastatic foci in the lung.

Conclusion

The clinicopathologic profiles of gastric extremely well differentiated adenocarcinoma of gastric phenotype include cardiac location, fungating gross type, very similar histology to foveolar epithelial hyperplasia, foveolar mucin phenotype, lack of p53 overexpressoin and high proliferative index.
Dual effect of the SR proteins ASF/SF2, SC35 and 9G8 on HIV-1 RNA splicing and virion production
Authors: Jacquenet Sandrine , Decimo Didier , Muriaux Delphine , Darlix Jean-Luc
Published: May 2005

In HIV-1 infected cells transcription of the integrated provirus generates the single full length 9 kb viral RNA, a major fraction of which is spliced to produce the single-spliced 4 kb RNAs and the multiple-spliced 2 kb RNAs. These spliced RNAs are the messengers for the Env glycoproteins and the viral regulatory factors. The cellular SR and hnRNP proteins were shown in vitro to control alternative splicing by binding cis-regulatory elements on the viral RNA. To better understand in vivo the role of the SR proteins on HIV-1 genomic RNA splicing and virion production, we used a human cell line expressing high levels of complete HIV-1 and either one of the ASF/SF2, SC35, and 9G8 SR proteins. Results show that over-expressing SR proteins caused a large reduction of genomic RNA and that each SR protein modified the viral 9 kb RNA splicing pattern in a specific mode. In fact, ASF/SF2 increased the level of Vpr RNA while SC35 and 9G8 caused a large increase in Tat RNA. As expected, overexpressing SR proteins caused a strong reduction of total Gag made. However, we observed by immuno-confocal microscopy an accumulation of Gag at the plasma membrane and in intracellular compartments while there is a dramatic reduction of Env protein made in most cells. Due to the negative impact of the SR proteins on the levels of genomic RNA and HIV-1 structural proteins much less virions were produced which retained part of their infectivity. In conclusion, SR proteins can down-regulate the late steps of HIV-1 replication.
Prime–boost vaccination with plasmid and adenovirus gene vaccines control HER2/neu
+metastatic breast cancer in mice
Authors: Wang Xiaoyan , Wang Jian-Ping , Rao Xiao-Mei , Price Janet E , Zhou Heshan S , Lachman Lawrence B
Published: May 2005

Introduction

Once metastasis has occurred, the possibility of completely curing breast cancer is unlikely, particularly for the 30 to 40% of cancers overexpressing the gene for HER2/neu. A vaccine targeting p185, the protein product of the HER2/neu gene, could have therapeutic application by controlling the growth and metastasis of highly aggressive HER2/neu+ cells. The purpose of this study was to determine the effectiveness of two gene vaccines targeting HER2/neu in preventive and therapeutic tumor models.

Methods

The mouse breast cancer cell line A2L2, which expresses the gene for rat HER2/neu and hence p185, was injected into the mammary fat pad of mice as a model of solid tumor growth or was injected intravenously as a model of lung metastasis. SINCP-neu, a plasmid containing Sindbis virus genes and the gene for rat HER2/neu, and Adeno-neu, an E1,E2a-deleted adenovirus also containing the gene for rat HER2/neu, were tested as preventive and therapeutic vaccines.

Results

Vaccination with SINCP-neu or Adeno-neu before tumor challenge with A2L2 cells significantly inhibited the growth of the cells injected into the mammary fat or intravenously. Vaccination 2 days after tumor challenge with either vaccine was ineffective in both tumor models. However, therapeutic vaccination in a prime–boost protocol with SINCP-neu followed by Adeno-neu significantly prolonged the overall survival rate of mice injected intravenously with the tumor cells. Naive mice vaccinated using the same prime–boost protocol demonstrated a strong serum immunoglobulin G response and p185-specific cellular immunity, as shown by the results of ELISPOT (enzyme-linked immunospot) analysis for IFNγ.

Conclusion

We report herein that vaccination of mice with a plasmid gene vaccine and an adenovirus gene vaccine, each containing the gene for HER2/neu, prevented growth of a HER2/neu-expressing breast cancer cell line injected into the mammary fat pad or intravenously. Sequential administration of the vaccines in a prime–boost protocol was therapeutically effective when tumor cells were injected intravenously before the vaccination. The vaccines induced high levels of both cellular and humoral immunity as determined by in vitro assessment. These findings indicate that clinical evaluation of these vaccines, particularly when used sequentially in a prime–boost protocol, is justified.
Immunohistochemical evaluation of human epidermal growth factor receptor 2 and estrogen and progesterone receptors in breast carcinoma in Jordan
Authors: Almasri Nidal M , Hamad Mohammad Al
Published: May 2005

Introduction

Although breast carcinoma (BC) is the most common malignancy affecting Jordanian females and the affected population in Jordan is younger than that in the West, no information is available on its biological characteristics. Our aims in this study are to evaluate the expression of estrogen receptor (ER) and progesterone receptor (PR) and Her-2/neu overexpression in BC in Jordan, and to compare the expression of these with other prognostic parameters for BC such as histological type, histological grade, tumor size, patients' age, and number of lymph node metastases.

Method

This is a retrospective study conducted in the Department of Pathology at Jordan University of Science and Technology. A confirmed 91 cases of BC diagnosed in the period 1995 to 1998 were reviewed and graded. We used immunohistochemistry to evaluate the expression of ER, PR, and Her-2. Immunohistochemical findings were correlated with age, tumor size, grade and axillary lymph node status.

Results

Her-2 was overexpressed in 24% of the cases. The mean age of Her-2 positive cases was 42 years as opposed to 53 years among Her-2 negative cases (p = 0.0001). Her-2 expression was inversely related to ER and PR expression. Her-2 positive tumors tended to be larger than Her-2 negative tumors with 35% overexpression among T3 tumors as opposed to 22% among T2 tumors (p = 0.13). Her-2 positive cases tended to have higher rates of axillary metastases, but this did not reach statistical significance. ER and PR positive cases were seen in older patients with smaller tumor sizes.

Conclusion

Her-2 overexpression was seen in 24% of BC affecting Jordanian females. Her-2 overexpression was associated with young age at presentation, larger tumor size, and was inversely related to ER and PR expression. One-fifth of the carcinomas were Her-2 positive and ER negative. This group appears to represent an aggressive form of BC presenting at a young age with large primary tumors and a high rate of four or more axillary lymph node metastases.
Differential responses to doxorubicin-induced phosphorylation and activation of Akt in human breast cancer cells
Authors: Li Xinqun , Lu Yang , Liang Ke , Liu Bolin , Fan Zhen
Published: May 2005

Introduction

We have shown previously that overexpression of constitutively active Akt or activation of Akt caused by constitutively active Ras or human epidermal growth factor receptor-2 (HER2) confers on breast cancer cells resistance to chemotherapy or radiotherapy. As an expanded study we here report differential responses in terms of phosphorylation and activation of Akt as a result of treatment with doxorubicin in a panel of breast cancer cell lines.

Methods

The levels of Akt phosphorylation and activity were measured by Western blot analysis with an anti-Ser473-phosphorylated Akt antibody and by in vitro Akt kinase assay using glycogen synthase kinase-3 as a substrate.

Results

Within 24 hours after exposure to doxorubicin, MCF7, MDA468 and T47D cells showed a drug-dose-dependent increase in the levels of phosphorylated Akt; in contrast, SKBR3 and MDA231 cells showed a decrease in the levels of phosphorylated Akt, and minimal or no changes were detected in MDA361, MDA157 and BT474 cells. The doxorubicin-induced Akt phosphorylation was correlated with increased kinase activity and was dependent on phosphoinositide 3-kinase (PI3-K). An increased baseline level of Akt was also found in MCF7 cells treated with ionizing radiation. The cellular responses to doxorubicin-induced Akt phosphorylation were potentiated after the expression of Akt upstream activators including HER2, HER3 and focal adhesion kinase.

Conclusion

Taken together with our recent published results showing that constitutive Akt mediates resistance to chemotherapy or radiotherapy, our present data suggest that the doxorubicin-induced phosphorylation and activation of Akt might reflect a cellular defensive mechanism of cancer cells to overcome doxorubicin-induced cytotoxic effects, which further supports the current efforts of targeting PI3-K/Akt for enhancing the therapeutic responses of breast cancer cells to chemotherapy and radiotherapy.
Renal blood flow in sepsis
Authors: Langenberg Christoph , Bellomo Rinaldo , May Clive , Wan Li , Egi Moritoki , Morgera Stanislao
Published: May 2005

Introduction

To assess changes in renal blood flow (RBF) in human and experimental sepsis, and to identify determinants of RBF.

Method

Using specific search terms we systematically interrogated two electronic reference libraries to identify experimental and human studies of sepsis and septic acute renal failure in which RBF was measured. In the retrieved studies, we assessed the influence of various factors on RBF during sepsis using statistical methods.

Results

We found no human studies in which RBF was measured with suitably accurate direct methods. Where it was measured in humans with sepsis, however, RBF was increased compared with normal. Of the 159 animal studies identified, 99 reported decreased RBF and 60 reported unchanged or increased RBF. The size of animal, technique of measurement, duration of measurement, method of induction of sepsis, and fluid administration had no effect on RBF. In contrast, on univariate analysis, state of consciousness of animals (P = 0.005), recovery after surgery (P < 0.001), haemodynamic pattern (hypodynamic or hyperdynamic state; P < 0.001) and cardiac output (P < 0.001) influenced RBF. However, multivariate analysis showed that only cardiac output remained an independent determinant of RBF (P < 0.001).

Conclusion

The impact of sepsis on RBF in humans is unknown. In experimental sepsis, RBF was reported to be decreased in two-thirds of studies (62 %) and unchanged or increased in one-third (38%). On univariate analysis, several factors not directly related to sepsis appear to influence RBF. However, multivariate analysis suggests that cardiac output has a dominant effect on RBF during sepsis, such that, in the presence of a decreased cardiac output, RBF is typically decreased, whereas in the presence of a preserved or increased cardiac output RBF is typically maintained or increased.
A quantitative analysis of the acidosis of cardiac arrest: a prospective observational study
Authors: Makino Jun , Uchino Shigehiko , Morimatsu Hiroshi , Bellomo Rinaldo
Published: May 2005

Introduction

Metabolic acidosis is common in patients with cardiac arrest and is conventionally considered to be essentially due to hyperlactatemia. However, hyperlactatemia alone fails to explain the cause of metabolic acidosis. Recently, the Stewart–Figge methodology has been found to be useful in explaining and quantifying acid–base changes in various clinical situations. This novel quantitative methodology might also provide useful insight into the factors responsible for the acidosis of cardiac arrest. We proposed that hyperlactatemia is not the sole cause of cardiac arrest acidosis and that other factors participate significantly in its development.

Methods

One hundred and five patients with out-of-hospital cardiac arrest and 28 patients with minor injuries (comparison group) who were admitted to the Emergency Department of a tertiary hospital in Tokyo were prospectively included in this study. Serum sodium, potassium, ionized calcium, magnesium, chloride, lactate, albumin, phosphate and blood gases were measured as soon as feasible upon arrival to the emergency department and were later analyzed using the Stewart–Figge methodology.

Results

Patients with cardiac arrest had a severe metabolic acidosis (standard base excess -19.1 versus -1.5; P < 0.0001) compared with the control patients. They were also hyperkalemic, hypochloremic, hyperlactatemic and hyperphosphatemic. Anion gap and strong ion gap were also higher in cardiac arrest patients. With the comparison group as a reference, lactate was found to be the strongest determinant of acidosis (-11.8 meq/l), followed by strong ion gap (-7.3 meq/l) and phosphate (-2.9 meq/l). This metabolic acidosis was attenuated by the alkalinizing effect of hypochloremia (+4.6 meq/l), hyperkalemia (+3.6 meq/l) and hypoalbuminemia (+3.5 meq/l).

Conclusion

The cause of metabolic acidosis in patients with out-of-hospital cardiac arrest is complex and is not due to hyperlactatemia alone. Furthermore, compensating changes occur spontaneously, attenuating its severity.
Randomized Phase III Trial of Cisplatin With or Without Topotecan in Carcinoma of the Uterine Cervix: A Gynecologic Oncology Group Study
Authors: Long Harry J. , Bundy Brian N. , Grendys Edward C. , Benda Jo Ann , McMeekin D. Scott , Sorosky Joel , Miller David S. , Eaton Lynne A. , Fiorica James V.
Published: May 2005

Purpose

On the basis of reported activity of methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC) or topotecan plus cisplatin in advanced cervix cancer, we undertook a randomized trial comparing these combinations versus cisplatin alone, to determine whether survival is improved with either combination compared with cisplatin alone, and to compare toxicities and quality of life (QOL) among the regimens.

Patients and Methods

Eligible patients were randomly allocated to receive cisplatin 50 mg/m2 every 3 weeks (CPT); cisplatin 50 mg/m2 day 1 plus topotecan 0.75 mg/m2 days 1 to 3 every 3 weeks (CT); or methotrexate 30 mg/m2 days 1, 15, and 22, vinblastine 3 mg/m2 days 2, 15, and 22, doxorubicin 30 mg/m2 day 2, and cisplatin 70 mg/m2 day 2 every 4 weeks (MVAC). Survival was the primary end point; response rate and progression-free survival (PFS) were secondary end points. QOL data are reported separately.

Results

The MVAC arm was closed by the Data Safety Monitoring Board after four treatment-related deaths occurred among 63 patients, and is not included in this analysis. Two hundred ninety-four patients enrolled onto the remaining regimens: 146 to CPT and 147 to CT. Grade 3 to 4 hematologic toxicity was more common with CT. Patients receiving CT had statistically superior outcomes to those receiving CPT, with median overall survival of 9.4 and 6.5 months (P = .017), median PFS of 4.6 and 2.9 months (P = .014), and response rates of 27% and 13%, respectively.

Conclusion

This is the first randomized phase III trial to demonstrate a survival advantage for combination chemotherapy over cisplatin alone in advanced cervix cancer.
Steroids and the Scientist
Authors: Gustafsson Jan-Åke
Published: May 2005

Our interest in nuclear receptors (NRs) originated from early studies on hepatic steroid metabolism. We discovered a new hypothalamo-pituitary-liver axis, imprinted neonatally by androgens and operating through sexually differentiated GH secretory patterns. Male and female patterns have opposite effects on sexually differentiated hepatic genes, explaining sexually dimorphic liver patterns. To further understand steroid action, we purified the glucocorticoid receptor (GR) leading to our discovery of the NR three-domain structure, with separable DNA binding domain and ligand binding domains and a third domain now known to have transcriptional regulatory properties. Knowledge of this domain structure has been immensely important for deciphering NR actions. Using this first purified NR, we collaborated with Keith Yamamoto and first demonstrated specific NR binding to DNA. This also was the first demonstration of a mammalian transcription factor, a breakthrough that led to discovery of NR response elements. In further collaboration with Yamamoto, we cloned the first NR cDNA sequences, leading to cloning of the superfamily of NR genes. With Yamamoto and Kaptein, we determined the first three-dimensional NR structure, that of DNA binding domain. Later work on orphan receptors resulted in the first discovery of: 1) endogenous ligands for an orphan receptor (fatty acids as activators of peroxisomal proliferator-activated receptor α); 2) liver X receptor β (OR-1) and its role in central nervous system cholesterol homeostasis; and 3) estrogen receptor β, leading to a paradigm shift in understanding of estrogen signaling, of importance in endocrinology, immunology, and oncology and to development of estrogen receptor β agonists for treatment of autoimmune diseases, prostate disease, depression, and ovulatory dysfunction.
The Contribution of “Alternative Approaches” to Understanding Steroid Hormone Action
Authors: Jensen Elwood V.
Published: May 2005

In the 47 yr since the first evidence for a steroid hormone receptor was presented at an international congress to an audience of five persons, the concept of “alternative approach” has played an important role in providing new understanding. By asking not what does an estrogenic hormone do to cellular processes in responsive tissues but what do these cells do to the hormone, it was shown that rat uterus contains a characteristic protein with which the hormone associates to promote growth. In the following decade, it was established that this substance is a true receptor, involved in hormonal action. Furthermore, estradiol was found not to undergo a chemical change as it exerts its effect. Finally, estrogenic action was established as a two-step process in which association with the hormone converts the receptor from an inactive to an active form that can bind tightly in the nucleus to modify transcription. These findings, obtained by studying the fate of the hormone itself, disproved the then accepted concept that estrogens interact with enzyme systems, and opened a new field of research. Soon various laboratories identified intracellular receptors for all classes of steroid hormones, the action of which involves a similar two-step process. Several laboratories then attempted, without success, to obtain antibodies to these receptors by conventional techniques. The unconventional approach of gradient ultracentrifugation, using radioactive estradiol as a marker for the receptor, gave a means of recognizing the soluble immune complexes formed with estrogen receptor and provided the first antibodies to any steroid hormone receptor, permitting its cloning. Finally, the knowledge that estrogens act through a receptor suggested that measuring the receptor content of an excised tumor specimen could identify, in advance, two thirds of the human breast cancers that are not estrogen dependent. These patients will not benefit from endocrine ablation or antiestrogen treatment and should be placed directly on chemotherapy. This is now standard clinical practice.
SymbioticHydraexpress a plant-like peroxidase gene during oogenesis
Authors: Habetha Matthias , Bosch Thomas C. G.
Published: May 2005

Symbiotic associations accompanied by gene exchange between the symbionts form the phylogenetic origin of eukaryotic cells and, therefore, had significant impact on species diversity and evolutionary novelty. Among the phylogenetically oldest metazoan animals known to form symbiotic relationships are the Cnidaria. In the Cnidarian Hydra viridis, symbiotic algae of the genus Chlorella are located in endodermal epithelial cells and impact sexual differentiation. When screening for Hydra viridis genes that are differentially expressed during symbiosis, we found a gene, HvAPX1, coding for a plant-related ascorbate peroxidase. HvAPX1 is expressed exclusively during oogenesis and in contrast to all known ascorbate peroxidase genes in plants does not contain introns. No member of this gene family has previously been identified from a member of the animal kingdom. We discuss the origin of the HvAPX1 gene and propose that it may have been transferred horizontally following an endosymbiotic event early in evolution of the Hydra lineage as an RNA or cDNA intermediate.
Learning in two contexts: the effects of interference and body size in bumblebees
Authors: Worden Bradley D. , Skemp Ana K. , Papaj Daniel R.
Published: May 2005

We examined the effect of learning a new task on the performance of a previously learned task with the same set of visual cues in bumblebees, Bombus impatiens. Previous studies have shown that given a binary choice at each task, bumblebees do not show retroactive interference, or mistakes in the first task, if the two tasks are in different contexts,feeding and nest location. Here we tested whether adding a third, unrewarded choice to each task affects the performance of bees learning in two contexts. In addition, we examined whether workers differ in their expression of interference and learning ability based on size. Performance of workers at a feeder task was degraded by the introduction of training to a second task at the nest entrance. Mistakes at the feeder were biased toward the color cue that was not rewarding in both tasks; suggesting that irrelevant or background stimuli are more prone to decay or forgetting during interference. With respect to interference, we did not find an effect of body size on the amount of interference; however, size was related to how quickly interference occurred. Among individuals showing retroactive interference, larger bees showed interference earlier in phase 2 than did smaller bees. Overall, larger workers learned each task more rapidly than smaller workers. We conclude that the timing of interference is a tradeoff between acquisition of the new task and performance at a previously learned task. Given that foragers in nature tend to be larger than nest workers, we suggest that size-related learning differences be considered as a factor in division of labor between large and small bumblebees.
Olfactory discrimination of female reproductive status by male tilapia(Oreochromis mossambicus)
Authors: Miranda A. , Almeida O. G. , Hubbard P. C. , Barata E. N. , Canário A. V. M.
Published: May 2005

The current study investigated whether discrimination of sexual status of female tilapia by males is mediated by olfaction. Size-matched groups of female tilapia were assigned as pre- or post-ovulatory according to the time since their last ovulation (15-19 days pre-ovulatory, N=7; 1-3 days post-ovulatory, N=8). Female-conditioned water and body fluids(urine, bile, faeces and plasma) were assessed for olfactory potency in males by recording the electro-olfactogram (EOG). Water extracts, urine and faeces from pre-ovulatory females all evoked significantly larger amplitude EOGs in male fish (N=6), with correspondingly lower thresholds of detection,than those from post-ovulatory females. Plasma and bile evoked very large amplitude EOGs in males but with no differences between the two groups of females. Anosmic males (N=6) did not behave differently towards pre-or post-ovulatory females, while sham-operated males (N=6) showed a marked increase in urination rate towards pre-ovulatory females. We conclude that the ability of male tilapia to discriminate between females of differing reproductive status is mediated by odorants released into the water, probably via the urine and faeces, by pre-ovulatory females.
Spider venom: enhancement of venom efficacy mediated by different synergistic strategies in Cupiennius salei
Authors: Wullschleger Benno , Nentwig Wolfgang , Kuhn-Nentwig Lucia
Published: May 2005

Besides the power of the chelicerae, synergistic interactions between different components in the venom of Cupiennius salei ensure the hunting success of this spider. The main components of the venom were tested alone or in combination according to their physiological venom concentrations in Drosophila bioassays. The high K+ ion content of the venom synergistically increases the insecticidal activity of the neurotoxins CSTX-1, CSTX-9 and CSTX-13 by 20% but does not influence the insecticidal effectiveness of the antimicrobially and cytolytically acting cupiennin 1a. Histamine only enhances the activity of the main neurotoxin CSTX-1. An important role in the envenomation process is exhibited by cupiennin 1a, which increases the insecticidal activity of the above-mentioned neurotoxins by up to 65%. Additionally, the highly synergistic effect of the enhancer CSTX-13 on CSTX-1, provoked in non-toxic physiological concentrations, could be verified for CSTX-9, but not for cupiennin 1a. CSTX-1 and CSTX-9 show positive interactions only when both are injected in toxic non-physiological concentrations.
Glutamate transporter type 3 attenuates the activation of N-methy-D-aspartate receptors co-expressed inXenopusoocytes
Authors: Zuo Zhiyi , Fang Hongyu
Published: May 2005

We studied the regulation of n-methy-d-aspartate receptor (NMDAR) current/activation by glutamate transporter type 3 (EAAT3), a neuronal EAAT in vivo, in the restricted extracellular space of a biological model. This model involved co-expressing EAAT3 and NMDAR (composed of NMDAR1-1a and NMDAR2A) in Xenopus oocytes. The NMDAR current was reduced in the co-expression oocytes but not in oocytes expressing NMDAR only when the flow of glutamate-containing superfusate was stopped. The degree of this current reduction was glutamate concentration-dependent. No reduction of NMDAR current was observed in Na+-free solution or when NMDA, a non-substrate for EAATs, was used as the agonist for NMDAR. In the continuous flow experiments, the dose-response curve of glutamate-induced current was shifted to the right-hand side in co-expression oocytes compared with oocytes expressing NMDAR alone. The degree of this shift depended on the abundance of EAAT3 in the co-expression oocytes. Thus, the glutamate concentrations sensed by NMDAR locally were lower than those in the superfusates. These results suggest that EAAT3 regulates the amplitude of NMDAR currents at pre-saturated concentrations of glutamate to EAAT3. Thus, EAATs, by rapidly regulating glutamate concentrations near NMDAR, modulate NMDAR current/activation.
Influence of local adaptation and interstock hybridization on the cardiovascular performance of largemouth bassMicropterus salmoides
Authors: Cooke Steven J. , Philipp David P.
Published: May 2005

In this study, the cardiovascular response to exhaustive exercise among differentiated stocks of largemouth bass Micropterus salmoides was compared at 10°C and 20°C to assess the level of their local adaptation. In addition, the impact that interstock hybridization had on adaptive differences was assessed using F1 hybrids. To accomplish these assessments, four genetically distinct stocks of fish were produced using adults from two regions in the midwestern United States identified as distinct conservation management units (central Illinois, IL and southeastern Wisconsin, WI): both P1 stocks and both reciprocal F1interstock hybrids. Cardiac variables (both resting and maximal) were consistently lowest for the IL×IL stock relative to the WI×WI stock and both F1 interstock hybrids. Interestingly, however, all groups of fish were able to maintain similar levels of cardiac scope. All fish responded to exercise by increasing heart rate and decreasing stroke volume,consistent with the notion that largemouth bass modulate cardiac output via frequency. After exercise, cardiac variables returned to resting levels 25-35% more rapidly for IL×IL fish relative to all other groups at 20°C. At 10°C, recovery rates for both P1 stocks were similar but more rapid than the interstock hybrids. Collectively, these results indicate that the locally adapted stock (IL×IL) exhibited cardiovascular adaptations that enabled rapid cardiovascular recovery and maintenance of low resting cardiac output and heart rate. Conversely, the translocated stock (WI×WI) and the interstock hybrids required longer for cardiovascular variables to recover after exercise and exhibited higher resting levels of cardiac output and heart rate. This study provides some of the first direct evidence of a physiological mechanism by which mixing stocks could potentially decrease fitness and illustrates the magnitude of the intraspecific diversity of cardiovascular performance.
A functional morphological approach to the scaling of the feeding system in the African catfish,Clarias gariepinus
Authors: Herrel Anthony , Van Wassenbergh Sam , Wouters Sarah , Adriaens Dominique , Aerts Peter
Published: May 2005

Effects of size are pervasive and affect nearly all aspects of the biology of animals and plants. Theoretical scaling models have been developed to predict the effects of size on the functioning of musculo-skeletal systems. Although numerous experimental studies have investigated the effects of size on the movements of skeletal elements during locomotion and feeding in vertebrates, relatively little is known about the scaling of the muscles and bones responsible for the actual movements. Here, we examine the scaling of external morphology, skeletal elements of the feeding system, and a number of cranial muscles to understand how this may affect the movements observed during suction feeding in the African catfish, Clarias gariepinus. The results show that neither the head nor the cranial elements themselves scale according to geometric similarity models. Relative to head size,distinct changes in the mass and configuration of the feeding structures takes place. Unexpectedly, different cranial muscles show different scaling patterns that ultimately all lead to a positive allometry of muscle cross-sectional area relative to fish head size. This suggests that (1) the scaling of the cranial elements cannot be predicted a priori based on the scaling of external head dimensions and (2) the scaling of the feeding system is optimised towards high force output in the larger animals. An analysis of the consequences of the observed changes in morphology with size on performance traits, including bite force and jaw closing velocity, suggests a tight link between the scaling of the feeding system and the natural diet of these fish. Whereas for smaller size classes the system is tuned towards high bite forces,for animals with cranial lengths greater than 65 mm the scaling of the feeding system appears to be dictated by the hydrodynamic constraints on suction feeding.
Functional classification of mitochondrion-rich cells in euryhaline Mozambique tilapia (Oreochromis mossambicus) embryos, by means of triple immunofluorescence staining for Na+/K+-ATPase,Na+/K+/2Cl- cotransporter and CFTR anion channel
Authors: Hiroi Junya , McCormick Stephen D. , Ohtani-Kaneko Ritsuko , Kaneko Toyoji
Published: May 2005

Mozambique tilapia Oreochromis mossambicus embryos were transferred from freshwater to seawater and vice versa, and short-term changes in the localization of three major ion transport proteins,Na+/K+-ATPase,Na+/K+/2Cl- cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR) were examined within mitochondrion-rich cells (MRCs) in the embryonic yolk-sac membrane. Triple-color immunofluorescence staining allowed us to classify MRCs into four types: type I, showing only basolateral Na+/K+-ATPase staining; type II, basolateral Na+/K+-ATPase and apical NKCC; type III, basolateral Na+/K+-ATPase and basolateral NKCC; type IV, basolateral Na+/K+-ATPase,basolateral NKCC and apical CFTR. In freshwater, type-I, type-II and type-III cells were observed. Following transfer from freshwater to seawater, type-IV cells appeared at 12 h and showed a remarkable increase in number between 24 h and 48 h, whereas type-III cells disappeared. When transferred from seawater back to freshwater, type-IV cells decreased and disappeared at 48 h, type-III cells increased, and type-II cells, which were not found in seawater, appeared at 12 h and increased in number thereafter. Type-I cells existed consistently irrespective of salinity changes. These results suggest that type I is an immature MRC, type II is a freshwater-type ion absorptive cell, type III is a dormant type-IV cell and/or an ion absorptive cell (with a different mechanism from type II), and type IV is a seawater-type ion secretory cell. The intracellular localization of the three ion transport proteins in type-IV cells is completely consistent with a widely accepted model for ion secretion by MRCs. A new model for ion absorption is proposed based on type-II cells possessing apical NKCC.
Effects of hypoxia acclimation on morpho-physiological traits over three generations of Daphnia magna
Authors: Seidl M. D. , Paul R. J. , Pirow R.
Published: May 2005

The mechanisms, dynamics and effects of hypoxia acclimation were studied in the water flea Daphnia magna over three successive generations(parental, first and second filial generation: P, F1 and F2). The P generation was raised under normoxic conditions at 20°C and became exposed to environmental hypoxia (10-19% air saturation)at maturity. Their progenies (F1 and F2) experienced hypoxia from birth onwards. Controls were kept under normoxic conditions. Individuals were successively sampled in a 3-day interval from each acclimation group to determine morpho-physiological parameters relevant in oxygen transport and regulation. Hypoxia acclimation induced adjustments at the haemoglobin (Hb) and metabolic level (within 3 days) but none at the systemic level. The convective performance and oxygen-sensitive control of the ventilatory and circulatory systems were the same in both acclimation groups. The Hb concentration and oxygen affinity increased by 266% and 32%,respectively. The 22% decrease in mass-specific oxygen consumption rate reduced the energy allocation to somatic growth without greatly affecting reproduction. The onset and duration of hypoxic exposure during ontogenesis have had a significant influence on Hb oxygen affinity and body size. Transgenerational effects of hypoxia acclimation could not be observed. The adjustments at the Hb and metabolic levels in combination with the smaller body size, which is advantageous to diffusive oxygen transport, reduced the critical ambient oxygen tension by approximately 50%.
CCA-1, EGL-19 and EXP-2 currents shape action potentials in theCaenorhabditis eleganspharynx
Authors: Shtonda Boris , Avery Leon
Published: May 2005

The pharynx of Caenorhabditis elegans is a tubular muscle controlled by its own set of neurons. We developed a technique to voltage clamp the pharyngeal muscle and demonstrate by analyzing mutants that the pharyngeal action potential is regulated by three major voltage-gated currents, conducted by a T-type calcium channel CCA-1, an L-type calcium channel EGL-19 and a potassium channel EXP-2.

We show that CCA-1 exhibits T-type calcium channel properties: activation at -40 mV and rapid inactivation. Our results suggest that CCA-1's role is to accelerate the action potential upstroke in the pharyngeal muscle in response to excitatory inputs. Similarly to other L-type channels, EGL-19 activates at high voltages and inactivates slowly; thus it may maintain the plateau phase of the action potential. EXP-2 is a potassium channel of the kV family that shows inward rectifier properties when expressed in Xenopus laevisoocytes. We show that endogenous EXP-2 is not a true inward rectifier - it conducts large outward currents at potentials up to +20 mV and is therefore well suited to trigger rapid repolarization at the end of the action potential plateau phase. Our results suggest that EXP-2 is a potassium channel with unusual properties that uses a hyperpolarization threshold to activate a regenerative hyperpolarizing current.
TheC. elegansT-type calcium channel CCA-1 boosts neuromuscular transmission
Authors: Steger Katherine A. , Shtonda Boris B. , Thacker Colin , Snutch Terrance P. , Avery Leon
Published: May 2005

Low threshold-activated or T-type calcium channels are postulated to mediate a variety of bursting and rhythmic electrical firing events. However,T-type channels' exact physiological contributions have been difficult to assess because of their incompletely defined pharmacology and the difficulty in isolating T-type currents from more robust high threshold calcium currents. A current in C. elegans pharyngeal muscle displays the kinetic features of a T-type calcium channel and is absent in animals homozygous for mutations at the cca-1 locus (see accompanying paper). cca-1is expressed in pharyngeal muscle and encodes a protein (CCA-1) with strong homology to the α1 subunits of vertebrate T-type channels. We show that CCA-1 plays a critical role at the pharyngeal neuromuscular junction, permitting the efficient initiation of action potentials in response to stimulation by the MC motor neuron. Loss of cca-1 function decreases the chance that excitatory input from MC will successfully trigger an action potential, and reduces the ability of an animal to take in food. Intracellular voltage recordings demonstrate that when wild-type cca-1 is absent, the depolarizing phase of the pharyngeal action potential tends to plateau or stall near -30 mV, the voltage at which the CCA-1 channel is likely to be activated. We conclude that the CCA-1 T-type calcium channel boosts the excitatory effect of synaptic input, allowing for reliable and rapid depolarization and contraction of the pharyngeal muscle. We also show that the pharyngeal muscle employs alternative strategies for initiating action potentials in certain cases of compromised MC motor neuron function.
Body wiping behaviors associated with cutaneous lipids in hylid tree frogs of Florida
Authors: Barbeau Tamatha R. , Lillywhite Harvey B.
Published: May 2005

Body wiping behavior, integumentary secretions and rates of evaporative water loss (EWL) were examined in six species of Florida tree frogs (Anura:Hylidae). Additionally, morphology of the integument and dermal glands were compared among these and one other Florida tree frog (Hyla andersonii), an arid-adapted tree frog (Phyllomedusa hypochondrialis), and a highly aquatic frog (Rana utricularia). An extra-epidermal layer of lipid and mucus, presumably secreted from dermal granular glands, was detected on the skin of all Florida hylid frogs examined. Distinct body wiping behaviors were observed in the hylid frogs, but these were less complex than those described previously in phyllomedusine frogs,which occupy arid habitats, secrete lipids onto their skin, and are regarded as relatively `waterproof'. Florida hylids occupy seasonally arid habitats and appear to have reduced rates of EWL. The suite of traits we observed in these frogs have been previously documented in a rhacophorid tree frog from seasonally arid regions of India and likely represent an evolutionary convergent response to periodic dehydration stress. The presence of lipids that are spread by simple wiping behaviors to form an extra-epidermal water barrier may represent an early stage of the more advanced adaptations described in more waterproof arboreal frogs.