The value of [18F]fluorodeoxyglucose-PET/CT in oesophageal cancer

[¹⁸F]Fluorodeoxyglucose-positron emission tomography/computed tomography (CT) is recognized as a useful adjunct to conventional imaging with CT and endoscopic ultrasonography for the staging of oesophageal cancer, for response assessment and identification of recurrent disease and it may provide prognostic information.

[(18)F]2-fluoro-2-deoxy-D-glucose PET/CT in mediastinal masses

Computed tomography (CT) and magnetic resonance imaging (MRI) are excellent modalities for the localization of mediastinal masses and there are often features that may allow the correct diagnosis to be made. However, CT and MRI cannot usually assess the aggressiveness of masses or identify viable tumour in residual masses after chemotherapy. Metabolic imaging using [¹⁸F]fluorodeoxyglucose (FDG)-positron emission tomography/CT, although not required in many cases, may be helpful for further characterization of masses and to guide the most appropriate site for biopsy.

Safety study of induction chemotherapy and synchronous radiotherapy (RT) and cetuximab in stage III non-small cell lung cancer (NSCLC): SCRATCH (Cohort I)

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Background: The addition of cetuximab can increase the efficacy of chemotherapy for advanced NSCLC. Concomitant cetuximab and RT is superior to RT alone for locally advanced squamous cell head & neck carcinoma. The SCRATCH study (cohort I) is a phase I study to assess the safety of synchronous cetuximab and radical RT in patients with Stage III NSCLC. Methods: Cohort I will contain 12 patients with inoperable stage III NSCLC. Inclusion criteria are performance status 0–1, adequate organ function, and disease encompassable within a radical RT volume. Exclusion criteria are previous malignancy, thoracic RT or treatment with EGFR targeted therapy. Patients receive platinum-based induction chemotherapy, followed by weekly intravenous cetuximab (initial dose 400mg/m2; maintenance dose 250mg/m2) and concomitant RT (64Gy/32fractions/45days). The primary end-point is toxicity. NCI Common Toxicity Criteria (CTC) V3.0 assessments are performed weekly during radiotherapy, and at regular follow-up visits. Results: Data from the first 9 patients is available. 2 patients stopped receiving cetuximab early due to toxicity. 1 experienced grade 3 fatigue following the initial dose, and the other declined further treatment after developing grade 2 skin toxicity. 2 patients have died, 1 from disease progression and 1 from thromboembolic disease. Both deaths occurred between months 2 and 4 post RT and were not attributed to the cetuximab therapy. Of the 7 living patients, 2 have survived 1 year (measured from the first day of induction chemotherapy). The maximum NCI CTC V3.0 scores are summarised in the table below. Conclusions: The results suggest that the early and late toxicities of synchronous cetuximab and radical RT are acceptable. Data on all 12 patients will be available by June 2007. SCRATCH Study cohorts II-IV follow on and will recruit sequentially. They will assess the safety of adding concomitant cisplatin (±vinorelbine) to cetuximab and radical RT.

[Table: see text]

No significant financial relationships to disclose.

MR urography: evaluation of different techniques in non-dilated tracts

OBJECTIVE

To assess the effectiveness of different MRI sequences for the visualisation of the different components of the non-dilated urinary tract.

METHOD

20 asymptomatic individuals were prospectively evaluated using 2 different heavily T2 weighted sequences, and after the injection of 2 different doses of gadolinium (Gd-DTPA). Images were independently scored.

RESULTS

The low dose Gd-DTPA enhanced MR urography (MRU) sequence was the best overall sequence for the visualisation of both the pelvicalyceal systems and ureters. The combination of information from the other sequences was additive.

CONCLUSIONS

Combined use of heavily T2 weighted and Gd-DTPA enhanced MRU produces diagnostic images and does not require pre-imaging preparation other than oral hydration.

Bilateral third and unilateral sixth nerve palsies as early presenting signs of metastatic prostatic carcinoma

PURPOSE

To report four cases of cranial nerve palsy, which presented to the ophthalmologist as the only or one of the earliest manifestations of prostatic carcinoma. This is an infrequent complication of metastatic prostatic carcinoma usually only occurring late in the disease process in those with a history of prostatic carcinoma.

METHODS

The case records of four patients with a history of a cranial nerve palsy who attended the ophthalmology department and who had a recent or subsequent diagnosis of prostatic carcinoma were reviewed.

RESULTS

Diplopia caused by lesions affecting the third and sixth nerves sometimes in association with sensory symptoms may be a manifestation of metastatic prostatic carcinoma. These findings are consistent with base of the skull metastases from the condition. Two patients are still alive 54 months and 12 months after the diagnosis. One of the patients died 13 months after the diagnosis of prostatic carcinoma was made and the other died 21 months after the diagnosis from an unrelated hypertensive brain haemorrhage.

CONCLUSIONS

Any patient presenting with diplopia must have an adequate past medical history taken and in an elderly gentleman this should include symptoms of prostatic disease. If indicated urological referral and measurement of prostate specific antigen may be performed. In patients whose cranial nerve palsy is complicated by other sensory signs or those in whom no sign of recovery occurs in 2 months, a contrast CT scan asking for bone windows to be included may be helpful in delineating any pathology. Radiotherapy may be useful for the treatment of metastatic prostatic carcinoma causing cranial nerve palsies with some patients experiencing either complete or partial resolution of their symptoms. The effect of newer hormonal agents or chemotherapy on this aspect of the disease is not well documented in current literature.

The UK national study of magnetic resonance imaging as a method of screening for breast cancer (MARIBS)

The UK national study of magnetic resonance imaging as a method of screening for breast cancer (MARIBS) is in progress. The study design, accrual to date, and related research projects are described. Revised accrual rates and expected recruitment are given. 15 cancers have been detected to date, from a total of 1236 screening measurements. This event rate and the tumour grades reported are compared with recent reports from other studies in women at high risk of breast cancer.

Salmonella enterica serotype Enteritidis phage types 4, 7, 6, 8, 13a, 29 and 34: a comparative analysis of genomic fingerprints from geographically distant isolates

AIMS

To evaluate genetic heterogeneity in the most common phage types of Salmonella enterica serovar Enteritidis.

METHODS AND RESULTS

A total of 233 isolates of Salm. Enteritidis from England, Northern Ireland, Spain, Hong Kong and the USA belonging to phage types (PT) 4 (n=88), PT7 (n=12), PT6 (n=72), PT8 (n=14), PT13a (n=29), PT29 (n=14) and PT34 (n=4) were characterized by PstI-SphI (PS) ribotyping and pulsed-field gel electrophoresis after digestion of DNA with XbaI. PS ribotyping differentiated the isolates into 53 different PS types and PFGE showed 14 different macrorestriction profiles; with the combination of both methods, 73 combined types were identified. Some of these clones appeared to be present within several countries. Movement of foodstuffs, animals or people may have been involved in the spread of these strains. On the other hand, some clones were only found in specific locations.

CONCLUSIONS

Several well defined clonal lines seem to co-exist within the different phage types included in this study, and a combined typing approach may constitute a useful tool for epidemiological investigations. Clustering analysis of ribotypes and PFGE types agree with previous studies and suggest that phage types that share receptor binding properties can be distinguished as two families: the PT4 family including PT7 and PT6, and the PT8 family including PT13a. The other phage types are difficult to place in a family unless the geographical site of isolation is known.

SIGNIFICANCE AND IMPACT OF THE STUDY

This paper reports on an extensive assessment of the use of molecular tools for the study of the epidemiology of the enteric pathogen Salm. Enteritidis. It also gives new information regarding relationships among some common phage types.

New strategies for polymer development in pharmaceutical science--a short review

We are developing synthetic polymers for pharmaceutical and medical applications. These applications can be broadly grouped on how the polymer will be utilized e.g. material, excipient or molecule. Our focus is to develop polymers with more defined structures that are based on biological, physicochemical and/or materials criteria. Strategies are being developed to more efficiently optimize structure-property correlations during preclinical development. We describe two examples of our research on pharmaceutical polymer development: narrow molecular weight distribution (MWD) homopolymeric precursors which can be functionalized to give families of narrow MWD homo- and co-polymers, and hydrolytically degradable polymers.

A comparison of the shuttle and 6 minute walking tests with measured peak oxygen consumption in patients with heart failure

This study investigated the use of an incremental, externally-paced 10 m shuttle walk test (SWT) as an objective, reliable and predictive test of functional capacity in patients with heart failure (CHF). The SWT was compared to a 6 minute walk test (6WT) and a maximal symptom-limited treadmill peak oxygen consumption (VO2peak) test. Experiment 1 examined the reproducibility of the SWT. Two SWF trials were performed and distance ambulated (DA), heart rate (HR) and rate of perceived exertion (RPE) results compared. In experiment 2, SWT, 6WT, and VO2 peak tests were performed and HR. RPE and ambulatory VO2 compared. The SWT demonstrated strong test/retest reliability for DA (r = 0.98). HR (r = 0.96) and RPE (r = 0.89). Treadmill VO2 peak was significantly correlated with DA during the SWT (r = 0.83, P < 0.05), but not the 6WT. SWT peak VO2 (18.5 +/- 1.8 ml.kg(-1) x min(-1)) and treadmill VO2 peak (18.3 +/-2.0 ml.kg(-1) x min(-1)) were also highly correlated (r = 0.78, P < 0.05). Conversely, 6WT peak VO2 and treadmill VO2 peak were not significantly correlated. This study suggests the SWT is a reliable, objective test, highly predictive of VO2 peak which may be a more optimal field exercise test than the self paced 6WT.

Advancing the science of symptom management

Since the publication of the original Symptom Management Model (Larson et al. 1994), faculty and students at the University of California, San Francisco (UCSF) School of Nursing Centre for System Management have tested this model in research studies and expanded the model through collegial discussions and seminars.

AIM

In this paper, we describe the evidence-based revised conceptual model, the three dimensions of the model, and the areas where further research is needed.

BACKGROUND/RATIONALE

The experience of symptoms, minor to severe, prompts millions of patients to visit their healthcare providers each year. Symptoms not only create distress, but also disrupt social functioning. The management of symptoms and their resulting outcomes often become the responsibility of the patient and his or her family members. Healthcare providers have difficulty developing symptom management strategies that can be applied across acute and home-care settings because few models of symptom management have been tested empirically. To date, the majority of research on symptoms was directed toward studying a single symptom, such as pain or fatigue, or toward evaluating associated symptoms, such as depression and sleep disturbance. While this approach has advanced our understanding of some symptoms, we offer a generic symptom management model to provide direction for selecting clinical interventions, informing research, and bridging an array of symptoms associated with a variety of diseases and conditions. Finally, a broadly-based symptom management model allows the integration of science from other fields.

Structural insights into the binding of cardiac glycosides to the digitalis receptor revealed by solid-state NMR

Several biologically active derivatives of the cardiotonic steroid ouabain have been made containing NMR isotopes ((13)C, (2)H, and (19)F) in the rhamnose sugar and steroid moieties, and examined at the digitalis receptor site of renal Na(+)/K(+)-ATPase by a combination of solid-state NMR methods. Deuterium NMR spectra of (2)H-labeled inhibitors revealed that the sugar group was only loosely associated with the binding site, whereas the steroid group was more constrained, probably because of hydrogen bonding to residues around the K(+)-channel region. Crosspolarization magic-angle spinning NMR showed that chemical shifts of inhibitors (13)C-labeled in the sugar group moved downfield by 0.5 ppm after binding to the digitalis site, suggesting that the sugar was close to aromatic side groups. A (19)F, (13)C- rotational-echo double-resonance NMR strategy was used to determine the structure of an inhibitor in the digitalis receptor site, and it showed that the ouabain derivatives adopt a conformation in which the sugar extends out of the plane of the steroid ring system. The combined structural and dynamic information favors a model for inhibition in which the ouabain analogues lie across the surface of the Na(+)/K(+)-ATPase alpha-subunit with the sugar group facing away from the surface of the membrane but free to move into contact with one or more aromatic residues.

2-Fluorine-18-fluoro-2-deoxy-D glucose positron emission tomography in the pretreatment staging of Hodgkin's disease: influence on patient management in a single institution

PURPOSE

Optimum therapy for patients with Hodgkin's disease (HD) is determined by a number of prognostic factors, one of which is an accurate definition of extent of disease (stage). Computerised tomography is widely used in staging but cannot reliably evaluate normal sized lymph nodes and some extranodal sites, e.g., liver, spleen and bone marrow. 2-Fluorine-18-fluoro-2-deoxy-D glucose (FDG) has been shown to concentrate preferentially in lymphoma sites (whether in nodal or extranodal tissue) and therefore may have a useful role in staging patients with HD. This study compares concurrent computerized tomography (CT) and FDG positron emission tomography (PET) in the staging of Hodgkin's disease and assesses the frequency of stage migration and possible changes in therapy related to the use of PET scanning.

PATIENTS AND METHODS

This was a single centre retrospective study of 44 patients with Hodgkin's disease who underwent both staging CT and PET prior to treatment between September 1993 and August 1998 at St. Thomas' Hospital. The number and sites of disease were assessed for each patient, documenting any stage and therapy modification prompted by PET findings.

RESULTS

One hundred fifty-nine sites of disease were demonstrated in forty-four patients by FDG-PET compared with eighty-four by CT. As a result, 18 (40.9%) patients were upstaged, nine of these by FDG-uptake in splenic or extranodal sites not visualised on CT. Only three patients were downstaged by PET results. Eleven patients (25%) had treatment modified by PET scan findings.

CONCLUSIONS

Significantly more sites of disease were identified by PET than CT resulting in stage changes and a modification of therapy in 25% of patients. This has important implications not only for current patient management but also for the design of future clinical trials.

Combined aerobic and resistance exercise training improves functional capacity and strength in CHF

This study examined the effect of a novel circuit weight training (CWT) program on cardiorespiratory fitness, muscular strength, and body composition in 13 patients with chronic heart failure (CHF), using a prospective randomized crossover protocol. Peak exercise oxygen uptake (VO(2 peak)) increased after the 8-wk CWT program (19. 5 +/- 1.2 vs. 22.0 +/- 1.5 ml. kg(-1). min(-1), P < 0.01), as did exercise test duration (15.2 +/- 0.9 vs. 18.0 +/- 1.1 min, P < 0. 001). Submaximal exercise heart rate was lower after training at 60 and 80 W (121 +/- 3 vs. 134 +/- 5 beats/min, P < 0.01) as was rate pressure product, whereas ventilatory threshold increased, from 52 +/- 3 to 58 +/- 3% of VO(2 peak) (P < 0.05). CWT also increased maximal isotonic voluntary contractile strength for seven different muscle groups, from 392 to 462 kg (P = 0.001). CWT, an exercise prescription specifically targeting peripheral abnormalities in CHF, improves functional capacity and muscular strength in these patients.

Eosinophil development and bone marrow and tissue eosinophils in atopic asthma

BACKGROUND

Eosinophils develop from bone marrow (BM) progenitors, and interleukin-5 (IL-5) and eotaxin may act in expansion and mobilisation of BM eosinophils in asthma.

METHODS

We have examined phenotypic changes as CD34+ cells develop to the eosinophil lineage in vitro, and have evaluated BM eosinophils from asthmatic and control subjects for expression of the eotaxin receptor, CCR3.

RESULTS

Acquisition of receptors for IL-5 and CCR3 was an early event in eosinophil development. There were increased CD34+ cells, and mature and immature CCR3+ eosinophils in BM from asthmatics.

CONCLUSION

These data suggest that IL-5 may act early in eosinophil development, and that eotaxin has the capacity to mobilise a BM eosinophil pool in asthma.

Computed tomography findings in an inflamed meckel diverticulum

Meckel diverticulum, the commonest congenital abnormality of the gastrointestinal tract, may be difficult to diagnose. Appearances on CT are often non-specific unless there is connection to the umbilicus or a complication has occurred. We report a case of an inflamed Meckel diverticulum seen on CT.

Macrophage scavenger receptor(s) and oxidatively modified proteins in endometriosis

OBJECTIVE

To determine whether cultured human peritoneal macrophages have functional scavenger receptor(s) and whether activation of macrophages in endometriosis may involve an increase in scavenger receptor activity.

DESIGN

A controlled clinical study comparing peritoneal fluid (PF) macrophages of women with endometriosis and controls without endometriosis.

SETTING

Women undergoing laparoscopic evaluation and treatment in a tertiary medical center.

PATIENT(S)

Twenty-one women undergoing evaluation for pelvic pain or infertility and 10 women undergoing elective laparoscopic tubal ligation.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Evidence for functional macrophage scavenger receptor and evidence of ligands for the scavenger receptor in PF.

RESULT(S)

Peritoneal macrophages of women with endometriosis degrade significantly more endothelial cell-low density lipoprotein (EC-LDL) and copper-oxidized LDL (Cu-LDL) than native LDL. Macrophages of women with endometriosis also incorporate more labeled oleic acid into cholesteryl ester in the presence of oxidized LDL (Ox-LDL) than in the presence of native LDL. Western blot analysis demonstrates the presence of adducts between lipid peroxidation products and proteins in PF of patients with and without endometriosis. The PF of women with endometriosis competes with labeled Ox-LDL for uptake by mouse peritoneal macrophages in a dose-dependent manner.

CONCLUSION(S)

We demonstrate for the first time that human macrophages have functional scavenger receptor(s) and that activation of macrophages in endometriosis involves an increase in scavenger receptor activity. Two lines of evidence indicate the presence of ligands for the scavenger receptor in PF.

Evidence for oxidatively modified lipid-protein complexes in endometrium and endometriosis

OBJECTIVE

To evaluate for the presence of oxidatively modified lipid-protein complexes in endometriosis and endometrium of women with endometriosis and controls.

DESIGN

Controlled clinical study.

SETTING

Academic tertiary care center.

PATIENT(S)

Women undergoing surgery for pelvic pain, infertility, endometriosis, or tubal ligation controls.

INTERVENTION(S)

Biopsy of endometrium and endometriosis.

MAIN OUTCOME MEASURE(S)

Staining with antibodies to oxidatively modified lipid proteins (HNE-7, MDA2), macrophages (HAM-56), and muscle cell actin (HHF-35).

RESULT(S)

Both endometrium and endometriosis tissues contain stromal cells that immunostain with HAM-56 and show immunostaining (both intracellular and extracellular) with HNE-7 and MDA2. Some endometriotic implants show patchy staining with HHF-35. Endometrium was devoid of staining with HHF-35. Control staining with nonimmune sera in both tissues was also devoid of staining.

CONCLUSION(S)

These data strongly implicate the occurrence of oxidative stress in endometriosis tissue. These data also suggest that oxidative modification is a normal physiological process in endometrium.

New-building occupancy. The role of nursing staff development

Orienting hospital staff to a new patient care facility presents many unique challenges for the Nursing Staff Development Department. Today's healthcare climate demands that staff orientation to a new facility be done quickly and with few disruptions to patient care. Nursing staff development specialists are well positioned to lead this process. Their expertise in program design, implementation and evaluation, problem solving and communication skills, and ability to view the learning needs of hospital staff holistically are vital to a successful facility move. This article will describe the opening of a new 150-bed inpatient facility in a large acute rehabilitation center. The principles used by the Nursing Staff Development Department in this new facility orientation process can be applied in multiple health care settings.

Implantable cardioverter defibrillators: physical and psychosocial outcomes

BACKGROUND: The long-term outcomes of living with an implantable cardioverter defibrillator are an important consideration in recovery. However, little is known about physical and psychosocial outcomes beyond 1 year after implantation. OBJECTIVE: To describe the long-term physical and psychosocial adaptation of persons who have had an implantable cardioverter defibrillator for approximately 2 years or more. METHODS: This nonexperimental cross-sectional study used telephone interviews to ascertain the responses of 80 recipients of implantable cardioverter defibrillators to physical and psychosocial questionnaires to explore the long-term outcomes of living with the devices. Subjects eligible for inclusion were selected from the files of an arrhythmia clinic. RESULTS: Hierarchical regression analysis showed that subjects who are not emotional are likely to be more physically active, especially if they are young and male, and that subjects who tend to be emotional are likely to be psychologically distressed and have poorer social and domestic adaptation. Furthermore, use of emotions was a positive predictor of psychological distress and poor social and domestic adaptation. Subjects reported the use of both emotion- and problem-focused coping. Subjects' scores on physical and psychosocial functioning were comparable to scores reported in the literature for patients who have had myocardial infarction or dysrhythmia. CONCLUSIONS: Emotional responses to distress were predictive of little physical activity and psychological distress. Furthermore, young recipients of implantable cardioverter defibrillators and men were predicted to be physically active. Persons who have had an implantable cardioverter defibrillator for approximately 2 years or more can anticipate that their physical and psychosocial functioning will be similar to that of patients who have myocardial infarction or dysrhythmia.

Implantable cardioverter defibrillators: physical and psychosocial outcomes

BACKGROUND

The long-term outcomes of living with an implantable cardioverter defibrillator are an important consideration in recovery. However, little is known about physical and psychosocial outcomes beyond 1 year after implantation.

OBJECTIVE

To describe the long-term physical and psychosocial adaptation of persons who have had an implantable cardioverter defibrillator for approximately 2 years or more.

METHODS

This nonexperimental cross-sectional study used telephone interviews to ascertain the responses of 80 recipients of implantable cardioverter defibrillators to physical and psychosocial questionnaires to explore the long-term outcomes of living with the devices. Subjects eligible for inclusion were selected from the files of an arrhythmia clinic.

RESULTS

Hierarchical regression analysis showed that subjects who are not emotional are likely to be more physically active, especially if they are young and male, and that subjects who tend to be emotional are likely to be psychologically distressed and have poorer social and domestic adaptation. Furthermore, use of emotions was a positive predictor of psychological distress and poor social and domestic adaptation. Subjects reported the use of both emotion- and problem-focused coping. Subjects' scores on physical and psychosocial functioning were comparable to scores reported in the literature for patients who have had myocardial infarction or dysrhythmia.

CONCLUSIONS

Emotional responses to distress were predictive of little physical activity and psychological distress. Furthermore, young recipients of implantable cardioverter defibrillators and men were predicted to be physically active. Persons who have had an implantable cardioverter defibrillator for approximately 2 years or more can anticipate that their physical and psychosocial functioning will be similar to that of patients who have myocardial infarction or dysrhythmia.

The surface contraction waves of Xenopus eggs reflect the metachronous cell-cycle state of the cytoplasm

Activated Xenopus laevis eggs undergo a series of surface contractions in response to cell-cycle progression but fall to cleave unless the sperm centrosome is present. These surface contraction waves (SCWs) begin at the animal pole and progress around the egg, occur every cell cycle and precede cleavage [1] [2] [3]. The SCWs are biphasic, comprising a relaxation phase (SCWa) and a contraction phase (SCWb). To investigate how these events are linked to the underlying cell cycle, we studied the temporal and spatial relationship between the SCWs and previously characterized biochemical markers of cell-cycle progression. We found that the relaxation phase was a response to activated maturation-promoting factor (MPF). In contrast, the contraction phase required inactivation of MPF and was blocked when MPF activity was maintained at elevated levels. We also found that a wave of MPF activity traveled within the cell from the animal to the vegetal hemisphere. Taken together, these experiments suggest that the SCWs are a local response to a wave of MPF activation and inactivation. The egg cytoplasm, therefore, is metachronous in terms of cell-cycle progression; multiple cell-cycle states are present and spatially distinct within the egg at the same time.

Haemostasis

There are many different methods and techniques used to achieve this in operating theatres, day procedure units and general practice surgeries around the country. I am aware that some of the methods which I am going to mention may not be available in all work areas but they are techniques which are synonymous with achieving haemostasis and are methods which you may want implemented in your area. So let me outline the topics I intend to look at in this session. First of all I would like to briefly outline the basic physiology behind coagulation, the body's natural response to bleeding. Then, I would like to mention a few drugs which can affect haemostasis and also look at the use of electrosurgery in achieving haemostasis. I would then intend to look at a few other techniques which are used such as suturing, tourniquets and pressure dressings.

Managing hypovolaemic shock

This poster has been designed to impart information which was gathered for a seminar as part of an Anaesthetic Nursing Course. It looks at the research which has been compiled on this subject, both in the Nursing and the Medical fields and illustrates the recommendations made by these pieces of research. The poster also depicts the breakdown of fluid compartments in the body and the physiological transference of fluids within the body in times of crisis. There is another section in the poster which explains the differences between certain fluids which are typically used during hypovolaemic resuscitation and the reasons for using these particular fluids. A version of a table designed by the American College of Surgeons, (Advanced Trauma Life Support, ATLS), which is recommended in some of the research on this topic is also shown in the poster and is very useful as a guide to what should happen in the hypovolaemic situation.

Requirement for phosphatidylinositol 3'-kinase activity in platelet-derived growth factor-stimulated tyrosine phosphorylation of p125 focal adhesion kinase and paxillin

The role of phosphatidylinositol 3'-kinase (PI 3'-kinase) activity in platelet-derived growth factor (PDGF)-stimulated tyrosine phosphorylation of focal adhesion kinase (p125FAK) and paxillin has been examined. The tyrosine phosphorylation of p125FAK and paxillin in response to PDGF was markedly inhibited by wortmannin in a dose-dependent manner. PDGF-stimulated PI 3'-kinase activity, membrane ruffle formation, and tyrosine phosphorylation of p125FAK and paxillin were all inhibited by the same low concentrations of wortmannin (>90% inhibition at 40nM). In contrast, tyrosine phosphorylation of p125FAK and paxillin in response to bombesin, endothelin, and phorbol 12,13-dibutyrate was not inhibited by wortmannin in these cells. Furthermore, LY294002, an inhibitor of PI 3'-kinase structurally unrelated to wortmannin, also inhibited PDGF-stimulated p125FAK tyrosine phosphorylation. PDGF was shown to stimulate the tyrosine phosphorylation of p125FAK in porcine aortic endothelial (PAE) cells transfected with the wild type PDGF-beta receptors, but not in PAE cells transfected with PDGF-beta receptors in which the PI 3'-kinase binding sites (Tyr-740/751) were replaced by phenylalanine. PDGF-stimulated, PI 3'-kinase-dependent tyrosine phosphorylation of p125FAK was not inhibited by rapamycin, and thus it was dissociated from the activation of p70 S6 kinase, previously identified as a molecular downstream target of PI 3'-kinase. Thus, we have identified a PI 3'-kinase-dependent signal transduction pathway in the action of PDGF, which leads to the phosphorylation of p125FAK and paxillin.

Effects of homology, size and exchange of the meiotic segregation of model chromosomes in Saccharomyces cerevisiae

In most eukaryotic organisms, chiasmata, the connections formed between homologous chromosomes as a consequence of crossing over, are important for ensuring that the homologues move away from each other at meiosis I. Some organisms have the capacity to partition the rare homologues that have failed to experience reciprocal recombination. The yeast Saccharomyces cerevisiae is able to correctly partition achiasmate homologues with low fidelity by a mechanism that is largely unknown. It is possible to test which parameters affect the ability of achiasmate chromosomes to segregate by constructing strains that will have three achiasmate chromosomes at the time of meiosis. The meiotic partitioning of these chromosomes can be monitored to determine which ones segregate away from each other at meiosis I. This approach was used to test the influence of homologous yeast DNA sequences, recombination intiation sites, chromosome size and crossing over on the meiotic segregation of the model chromosomes. Chromosome size had no effect on achiasmate segregation. The influence of homologous yeast sequences on the segregation of noncrossover model chromosomes was negligible. In meioses in which two of the three model chromosomes experienced a crossover, they nearly always disjoined at meiosis I.

Phage conversion in Salmonella enterica serotype Enteritidis: implications for epidemiology

A model system for the study of phage conversion of Salmonella enterica serotype Enteritidis is reported. Temperate phages 1,2,3 and 6 from the phage typing scheme were used to convert several individually recognized phage types into others. Phage type 4 was converted to PT8, PT6a to PT4, PT6a to PT7, PT13 to PT13a and PT15 to PT11; some new phage lysis patterns were also detected. This model was used to examine the relationships between phage types within a previously defined clonal lineage, SECLIII, to establish whether or not Enteritidis like Salmonella enterica serotype Typhi and Salmonella enterica serotype Paratyphi B possessed type determining phages. We were able to convert PT1 to PT20, and PT15 to PT11.

Botulinum C3 exoenzyme blocks the tyrosine phosphorylation of p125FAK and paxillin induced by bombesin and endothelin

In this study we examined the role of rho p21 in neuropeptide-stimulated tyrosine phosphorylation. Intact Swiss 3T3 cells were treated with the Clostridium botulinum C3 exoenzyme which specifically ADP ribosylates and inactivates rho p21. C3 exoenzyme treatment of cells caused a marked decrease in both bombesin- and endothelin-stimulated tyrosine phosphorylation of multiple proteins, including p125 focal adhesion kinase (FAK) and paxillin. Our results suggest that rho p21 is a component of the signal transduction pathway linking seven transmembrane domain receptors with tyrosine phosphorylation and cytoskeletal events.

Platelet-derived growth factor modulation of focal adhesion kinase (p125FAK) and paxillin tyrosine phosphorylation in Swiss 3T3 cells. Bell-shaped dose response and cross-talk with bombesin

In the present study, we have identified several proteins in Swiss 3T3 cells that are phosphorylated on tyrosine in response to platelet-derived growth factor (PDGF) and exhibit an unusual bell-shaped dose-response curve with a maximum at 5 ng/ml platelet-derived growth factor (PDGF). These proteins include two that are associated with focal adhesions, namely the focal adhesion kinase (p125FAK), a novel cytosolic tyrosine kinase, and paxillin. At low concentrations of PDGF (1-5 ng/ml), these proteins are the predominant tyrosine-phosphorylated species. At 30 ng/ml PDGF, however, there was no stimulation of their phosphorylation over control levels. In contrast, tyrosine phosphorylation of previously described substrates of the PDGF receptor tyrosine kinase, namely the p21ras GTPase-activating protein, p120, phosphatidyl inositol 3' kinase, and phospholipase C gamma exhibited sigmoidal dose-response curves with PDGF and were all efficiently phosphorylated on tyrosine at 30 ng/ml PDGF. Cytochalasin D, which disrupts the actin cytoskeleton, completely inhibited the tyrosine phosphorylation of p125FAK and paxillin by PDGF. Examination of the actin cytoskeleton after stimulation of cells with different concentrations of PDGF revealed that at 5 ng/ml PDGF, actin appears in stress fibers and in membrane ruffles, while at 30 ng/ml, PDGF disrupts the actin cytoskeleton. Bombesin stimulates actin stress fiber formation with no evidence of disruption of stress fibers at high concentrations. When cells were stimulated with bombesin (10 nM) in the presence of 30 ng/ml PDGF, however, the actin cytoskeleton was completely disrupted. Further, the tyrosine phosphorylation of both p125FAK and paxillin induced by bombesin (10 nM) was completely prevented when cells were stimulated with bombesin in the presence of 30 ng/ml PDGF. We propose that the inhibitory limb in the bell-shaped dose-response curve of PDGF and the novel cross-talk between PDGF and bombesin on tyrosine phosphorylation may be explained by the ability of PDGF at 30 ng/ml to disrupt the actin cytoskeleton.