Monensin toxicosis in 2 sheep flocks

Several lambs in 2 sheep flocks died suddenly and others were examined for generalized weakness and dyspnea. Postmortem findings were suggestive of degenerative myocardial and skeletal muscle myopathy, which was confirmed histologically. Feed analysis revealed toxic levels of monensin and ionophore toxicosis was diagnosed.

Human bladder cancer invasion model using rat bladder in vitro and its use to test mechanisms and therapeutic inhibitors of invasion

As well as being a passive support, the extracellular matrix also regulates key biological processes such as invasion, differentiation and angiogenesis. We have therefore developed an in vitro model of bladder cancer invasion using de-epithelialized rat bladder to allow for tumour cell-extracellular matrix interactions. Onto this we have seeded a panel of human bladder cancer cell lines (RT4, RT112, 253J and EJ28 (T24)) representing progression from well to poorly differentiated phenotypes and used as models of superficial to invasive bladder cancer. The better differentiated cell lines RT4 and RT112 reproducibly grew as stratified epithelium, whereas poorly differentiated EJ28 cells invaded across a broad front. Invasion was not simply related to proliferation rate, measured either as doubling time on plastic (non-invasive 253J and invasive EJ28 having the same doubling time) or by Ki-67 proliferation index within the model. We used the model to test the ability of 4 compounds that interfere with tumour cell-extracellular matrix interactions (suramin, N-acetylcysteine and the urokinase plasminogen activator pathway antagonists A5 compound and monoclonal antibody Mab 3936) to inhibit invasion. At non-toxic concentrations, all significantly inhibited invasion (P< 0.05), although to varying degrees, suramin and A5 almost completely and N-acetylcysteine the least. In conclusion, this model shows the urokinase system is important for bladder invasion and can be used to investigate other mechanisms of bladder cancer invasion and also for the testing of intravesical drugs.

Total chemical synthesis and chemotactic activity of human S100A12 (EN-RAGE)

Human S100A12 (extracellular newly identified RAGE (receptor for advanced glycosylation end products)-binding protein), a new member of the S100 family of EF-hand calcium-binding proteins, was chemically synthesised using highly optimised 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate/tert-butoxycarbonyl in situ neutralisation solid-phase chemistry. Circular dichroism studies indicated that CaCl(2) decreased the helical content by 27% whereas helicity was marginally increased by ZnCl(2). The propensity of S100A12 to dimerise was examined by electrospray ionisation time-of-flight mass spectrometry which clearly demonstrated the prevalence of the non-covalent homodimer (20890 Da). Importantly, synthetic human S100A12 in the nanomolar range was chemotactic for neutrophils and macrophages in vitro.

Assessment of angiogenic factors the chick chorioallantoic membrane assay

Angiogenesis is the growth of new vessels from existing vessels. It is important in the physiological processes of wound healing, embryogenesis, and the female menstrual cycle and involved in pathologies such as diabetic retinopathy and rheumatoid arthritis (1). There is now abundant evidence that tumors are angiogenesis dependent. Unless tumors can stimulate angiogenesis, and generate their own blood supply, they fail to grow larger than 2-3 mm(3). The angiogenic status of a tumor can be assessed directly using immunohistochem istry on pathology sections (see Chapter 13 by Kilic and Ergün in this volume and Chapter 7 by Ranieri and Gasparini and Chapter 8 by Turner and Harris in the companion volume) to count the number of blood vessels within a given area (microvessel density [MVD]). MVD is a prognostic indicator in a number of tumors including breast, bladder, and prostate (2). Angiogenic capacity can also be measured by assaying the various stimulatory and inhibitory factors that regulate angiogenesis. This can be done either by determining the mRNA level using ribonuclease protection (see Chapter 16 by Jones et al. in the companion volume) or the protein by either Western blotting (see Chapter 11 by Blancher and Jones in the companion volume) or with one of the commercially available enzyme-linked immunosorbent assay (ELISA) kits. Again, levels of these factors have been shown to be prognostic in a number of tumors.

SDS -PAGE and Western Blotting Techniques

The goal of Western blotting, or more correctly, immunoblotting, is to identify with a specific antibody a particular antigen within a complex mixture of proteins that has been fractionated in a polyacrylamide gel and immobilized onto a membrane. Immunoblotting can be used to determine a number of important characteristics of protein antigens-the presence and quantity of an antigen, the relative molecular weight of the polypeptide chain, and the efficiency of extraction of the antigen.Immunoblotting occurs in six stages: (1) extraction and quantification of protein samples; (2) resolution of the protein sample in sodium dodecyl sulfatepolyacrylamide denaturing gel electrophoresis (SDS-PAGE); (3) transfer of the separated polypeptides to a membrane support; (4) blocking nonspecific binding sites on the membrane; (5) addition of antibodies; and (6) detection.Sample preparation is important for obtaining accurate separation of the proteins on the basis of molecular weight. Depending on whether an antigen is primarily extracellular, cytoplasmic, or membrane-associated different procedures might be required to prepare the sample initially. Although there are exceptions, many soluble nuclear and cytoplasmic proteins can be solubilized by lysis buffers that contain the nonionic detergent Nonidet P-40 (NP-40) and either no salt at all or relatively high concentrations of salt (e.g., 0.5 M NaCl). However, the efficiency of extraction is often greatly affected by pH of the buffer and the presence or absence of chelating agents such EDTA.

Evaluating a community-based multiprofessional course in community health

PURPOSE

To evaluate student response to a community health course taught using a small-group, interdisciplinary, service-learning approach.

METHOD

Student evaluations for the course were reviewed for a 3-year period (1994 1997).

RESULTS

Student evaluations of the course improved over the 3-year period. A total of 60-76% of the students indicated that they preferred the small-group experiential approach to lectures. Examination of evaluation scores for individual small groups showed that some small groups gave the course very high ratings, while others found the experience inadequate.

CONCLUSION

A course in community health is best taught in the community rather than the classroom. A small-group approach may result in a course with considerable variation among groups as a result of variations in community receptivity, faculty skills, and perhaps other factors.

V(D)J recombination defects in lymphocytes due to RAG mutations: severe immunodeficiency with a spectrum of clinical presentations

Severe combined immunodeficiency (SCID) comprises a heterogeneous group of primary immunodeficiencies, a proportion of which are due to mutations in either of the 2 recombination activating genes (RAG)-1 and -2, which mediate the process of V(D)J recombination leading to the assembly of antigen receptor genes. It is reported here that the clinical and immunologic phenotypes of patients bearing mutations in RAGs are more diverse than previously thought and that this variability is related, in part, to the specific type of RAG mutation. By analyzing 44 such patients from 41 families, the following conclusions were reached: (1) null mutations on both alleles lead to the T-B-SCID phenotype; (2) patients manifesting classic Omenn syndrome (OS) have missense mutations on at least one allele and maintain partial V(D)J recombination activity, which accounts for the generation of residual, oligoclonal T-lymphocytes; (3) in a third group of patients, findings were only partially compatible with OS, and these patients, who also carried at least one missense mutation, may be considered to have atypical SCID/OS; (4) patients with engraftment of maternal T cells as a complication of a transplacental transfusion represented a fourth group, and these patients, who often presented with a clinical phenotype mimicking OS, may be observed regardless of the type of RAG gene mutation. Analysis of the RAG genes by direct sequencing is an effective way to provide accurate diagnosis of RAG-deficient as opposed to RAG-independent V(D)J recombination defects, a distinction that cannot be made based on clinical and immunologic phenotype alone.

Psychological problems following ICU treatment

Treatment in an intensive care unit can be stressful and may leave patients with persisting psychological symptoms that impair quality of life. This postal questionnaire study of patients who had previously been treated in a general adult intensive care unit showed that 38 (47%) of 80 patients who returned fully completed questionnaires reported clinically significant anxiety and depression as measured by the Hospital Anxiety and Depression Scale. Thirty (38%) reported significant symptoms of post-traumatic stress disorder, of whom 12 (15%) reached levels consistent with a diagnosis of full post-traumatic stress disorder as measured by the Trauma Symptom Checklist 33 and the Impact of Events Scale. We describe a new measure of psychological distress specifically related to the experience of intensive care management, the Experience after Treatment in Intensive Care 7 Item Scale, and compare it to the other scales. The Experience after Treatment in Intensive Care 7 Item Scale shows that at least a proportion of the post-traumatic stress reported was directly attributable to the experience of treatment in the intensive care unit.

Hospital care pathways for patients with schizophrenia

Greater emphasis is being placed on reducing clinical variation in managing patient groups in the reformed National Health Service (NHS) in the United Kingdom (UK). The use of a care pathway to enable greater control over the process and quality of care will be explored for patients suffering from schizophrenia. The paper addresses three main factors for the development of care pathways for people suffering from schizophrenia: predictability of the illness; nature of standardized care; and role autonomy. It is argued that the diagnosis of schizophrenia does not lend itself easily to predicting care and treatment within a care pathway framework. However, a care pathway may bring other benefits, such as standardized care and a greater control over the delivery of care. Development and implementation of hospital care pathways require extensiv research. Qualitative research directions are advocated due to the possib difficulties of conducting an experimental study.

Pharmacokinetics and safety of escalating single and repeat oral doses of GW420867X, a novel non-nucleoside reverse transcriptase inhibitor

OBJECTIVE

To assess the pharmacokinetics, safety and tolerability of escalating oral doses of GW420867X, a non-nucleoside reverse transcriptase inhibitor, was investigated in healthy male volunteers in a randomized, double-blind placebo-controlled study.

METHODS

Study subjects were divided into four groups of 12 subjects (10, 50, 100 and 200-mg dose groups) with eight subjects from each group receiving active treatment and the remaining four matched placebo. Subjects were initially administered a single dose of GW420867X or placebo, and following a 24- to 28-day washout period, re-exposed to the same treatment for 14 consecutive days. Safety measurements including clinical laboratory evaluations, ECG and vital signs were performed before, during and after dosing.

RESULTS

Geometric mean GW420867X peak plasma concentrations (Cmax) following single oral doses of 10, 50, 100 and 200 mg were 160, 608, 1,000 and 1,662 ng/ml, respectively. Time to Cmax (tmax) increased from a median value of 1 h following the 10-mg dose, to 3 h after the 200-mg dose. Geometric mean plasma areas under the curves (AUC) were 4,325 (10 mg), 17,862 (50 mg), 35,295 (100 mg) and 62,338 ng/ml per hour (200 mg) and were proportionally less than the increase in the administered dose. Apparent terminal elimination half-life (t1/2) was approximately 50 h. Following repeat dosing, accumulation ratios based on plasma AUC were: 3.0+/-1.0 (10mg), 2.6+/-0.9 (50mg), 1.8+/-0.3 (100 mg) and 1.9+/-0.8 (200 mg) after 14 days of dosing compared to the corresponding single dose. In general, oral clearance (CL/F) was greater after 14 days and greater with higher doses except for the 10-mg dose group. Steady-state CL/F was 2.2, 3.4, 4.2, and 5.1 l/h for 10, 50, 100, and 200 mg, respectively. Steady-state was generally achieved within 7-10 days. Comparison of single and repeat dosing with GW420867X showed that Cmax increased by a factor of between 1.4 to 1.8, after 14 days of daily dosing to 288 (10 mg), 1,006 (50 mg), 1,401 (100 mg) and 2,613 (200 mg) ng/ml. These increases were proportionally less than the increase in the administered dose. GW420867X was well tolerated by subjects both after single and repeated dosing. Adverse effects reported by subjects on the active drug were similar to those receiving placebo. All episodes were rated as mild to moderate in severity and resolved spontaneously without further intervention.

CONCLUSION

The pharmacokinetic findings of this study imply that systemic exposure to GW420867X decreases with increasing dose and displays time-variant pharmacokinetics, which suggests decreased absorption and/or increased clearance of GW420867X. The relatively long plasma half-life, of approximately 50 h, makes it suitable for once-daily dosing.

Qualitative study of views of health professionals and patients on guided self management plans for asthma

OBJECTIVES

To explore the views held by general practitioners, practice nurses, and patients about the role of guided self management plans in asthma care.

DESIGN

Qualitative study using nine focus groups that each met on two occasions.

SETTING

South Wales.

SUBJECTS

13 asthma nurses, 11 general practitioners (six with an interest in asthma), and 32 patients (13 adults compliant with treatment, 12 non-compliant adults, and seven teenagers).

RESULTS

Neither health professionals nor patients were enthusiastic about guided self management plans, and, although for different reasons, almost all participants were ambivalent about their usefulness or relevance. Most professionals opposed their use. Few patients reported sustained use, and most felt that plans were largely irrelevant to them. The attitudes associated with these views reflect the gulf between the professionals' concept of the "responsible asthma patient" and the patients' view.

CONCLUSIONS

Attempts to introduce self guided management plans in primary care are unlikely to be successful. A more patient centred, patient negotiated plan is needed for asthma care in the community.

Qualitative interview study of communication between parents and children about maternal breast cancer

OBJECTIVE

To examine parents' communication with their children about the diagnosis and initial treatment of breast cancer in the mother.

DESIGN

Qualitative interview study within a cross-sectional cohort.

SETTING

Two breast cancer treatment centers.

PARTICIPANTS

32 women with stage I or stage II breast cancer with 56 school-aged children. Main outcome measures Semistructured interview regarding timing and extent of communication with children about the diagnosis and initial treatment of the mother's illness, reasons for talking to children or withholding information, and help available and requested from health professionals.

RESULTS

Women were most likely to begin talking to their children after their diagnosis had been confirmed by biopsy, but a few waited until after surgery or said nothing at all. Family discussion did not necessarily include mention of cancer. There was considerable consistency in the reasons given for either discussing or not discussing the diagnosis. The most common reason for not communicating was to avoid children's questions, particularly those about death. Although most women had helpful discussion with a physician concerning their illness, few were offered help with talking to their children; many would have liked help, particularly the opportunity for both parents to talk to a health professional with experience in understanding and talking to children.

CONCLUSION

Parents diagnosed with cancer or other serious illnesses should be offered help to think about whether, what, and how to tell their children and about what children can understand, especially as they may well be struggling themselves to come to terms with their illness.

The Caenorhabditis elegans dosage compensation machinery is recruited to X chromosome DNA attached to an autosome

The dosage compensation machinery of Caenorhabditis elegans is targeted specifically to the X chromosomes of hermaphrodites (XX) to reduce gene expression by half. Many of the trans-acting factors that direct the dosage compensation machinery to X have been identified, but none of the proposed cis-acting X chromosome-recognition elements needed to recruit dosage compensation components have been found. To study X chromosome recognition, we explored whether portions of an X chromosome attached to an autosome are competent to bind the C. elegans dosage compensation complex (DCC). To do so, we devised a three-dimensional in situ approach that allowed us to compare the volume, position, and number of chromosomal and subchromosomal bodies bound by the dosage compensation machinery in wild-type XX nuclei and XX nuclei carrying an X duplication. The dosage compensation complex was found to associate with a duplication of the right 30% of X, but the complex did not spread onto adjacent autosomal sequences. This result indicates that all the information required to specify X chromosome identity resides on the duplication and that the dosage compensation machinery can localize to a site distinct from the full-length hermaphrodite X chromosome. In contrast, smaller duplications of other regions of X appeared to not support localization of the DCC. In a separate effort to identify cis-acting X recognition elements, we used a computational approach to analyze genomic DNA sequences for the presence of short motifs that were abundant and overrepresented on X relative to autosomes. Fourteen families of X-enriched motifs were discovered and mapped onto the X chromosome.

Cloning of the Aspergillus oryzae 5-aminolevulinate synthase gene and its use as a selectable marker

The hemA gene encoding 5-aminolevulinate synthase, the first enzyme in heme biosynthesis, was cloned from Aspergillus oryzae and evaluated as a selectable marker for the transformation of filamentous fungi. Deletion of the hemA gene resulted in a lethal phenotype that could be rescued either by the supplementation of culture media with 5-aminolevulinic acid (ALA) or by transformation with the wild-type hemA gene, but not by growth on rich media, nor by the addition of exogenous heme. Transformation of a hemA deletion strain with the hemA gene linked to a lipase expression cassette yielded ALA prototrophs expressing lipase. The hemA gene can therefore be used as a selectable marker for the transformation of A. oryzae.

Accuracy and limitations of transabdominal fetal echocardiography at 12-15 weeks of gestation in a population at high risk for congenital heart disease

OBJECTIVE

Evaluation of transabdominal fetal echocardiography at 12-15 weeks of gestation.

DESIGN

Retrospective analysis.

SETTING

Tertiary fetal cardiology unit.

SAMPLE

Two hundred twenty-nine consecutive fetuses imaged at 12-15 weeks of gestation over a 45-month period.

METHODS

Retrospective analysis of echocardiography and autopsy reports.

MAIN OUTCOME MEASURES

Accuracy of early echocardiography for the detection of abnormalities of the cardiac connections.

RESULTS

Diagnostic images were obtained in 226/229 fetuses (98.7%). Abnormalities of the cardiac connections were detected in 13 fetuses (5.7%) on the initial scan. Where information was available (n = 11), the echocardiographic findings were confirmed at autopsy or postnatally. In two of the 13 cases of congenital heart disease, repeat echocardiography was necessary to provide additional cardiological information. Of the 213 cases in whom a normal initial report was issued, four (1.7%) had congenital heart disease diagnosed later in pregnancy (n = 3) or postnatally (n = 1). Three of these fetuses had haemodynamically insignificant ventricular septal defects and one developed a dilated cardiomyopathy later in gestation.

CONCLUSIONS

Transabdominal fetal echocardiography can be performed at 12-15 weeks of gestation permitting accurate early detection of major congenital heart defects in a high risk population. Some forms of congenital heart disease, usually minor, may not be detectable at such an early stage.

Thymidine phosphorylase induces carcinoma cell oxidative stress and promotes secretion of angiogenic factors

Thymidine phosphorylase (TP) (E.C. 2.4.2.4), also known as platelet-derived endothelial cell growth factor, is a potent angiogenic factor. The expression of TP correlates with poor prognosis in a range of tumor types. 2-Deoxy-D-ribose-1-phosphate, a product of thymidine catabolism by TP, is a strongly reducing sugar that generates oxygen radical species during the early stages of protein glycation. We show that thymidine induces oxidative stress in TP-overexpressing carcinoma cells, promoting secretion of the stress-induced angiogenic factors vascular endothelial growth factor and interleukin-8, and inducing matrix metalloproteinase-1. Our findings outline a putative mechanism for TP-induced angiogenesis and identify novel targets for intervention.

Novel omega-conotoxins from Conus catus discriminate among neuronal calcium channel subtypes

omega-Conotoxins selective for N-type calcium channels are useful in the management of severe pain. In an attempt to expand the therapeutic potential of this class, four new omega-conotoxins (CVIA-D) have been discovered in the venom of the piscivorous cone snail, Conus catus, using assay-guided fractionation and gene cloning. Compared with other omega-conotoxins, CVID has a novel loop 4 sequence and the highest selectivity for N-type over P/Q-type calcium channels in radioligand binding assays. CVIA-D also inhibited contractions of electrically stimulated rat vas deferens. In electrophysiological studies, omega-conotoxins CVID and MVIIA had similar potencies to inhibit current through central (alpha(1B-d)) and peripheral (alpha(1B-b)) splice variants of the rat N-type calcium channels when coexpressed with rat beta(3) in Xenopus oocytes. However, the potency of CVID and MVIIA increased when alpha(1B-d) and alpha(1B-b) were expressed in the absence of rat beta(3), an effect most pronounced for CVID at alpha(1B-d) (up to 540-fold) and least pronounced for MVIIA at alpha(1B-d) (3-fold). The novel selectivity of CVID may have therapeutic implications. (1)H NMR studies reveal that CVID possesses a combination of unique structural features, including two hydrogen bonds that stabilize loop 2 and place loop 2 proximal to loop 4, creating a globular surface that is rigid and well defined.

Transcranial Doppler (TCD) screening for stroke prevention in sickle cell anemia: pitfalls in technique variation

BACKGROUND

The Stroke Prevention Trial in Sickle Cell Anemia (STOP) identified children as being at high stroke risk if the time-averaged maximum mean velocity (TAMMV) of the middle cerebral or intracranial internal carotid arteries measured > or = 200 cm/s. These values were obtained utilizing a 2-mHz dedicated nonimaging pulsed Doppler technique (TCD) and manual measurements. Questions have been raised as to the comparability of results obtained with different ultrasound machines and measurement techniques.

OBJECTIVE

The purpose of this study was to compare nonimaging (TCD) and transcranial duplex imaging (TCDI) findings in children potentially at risk for stroke with sickle cell disease.

MATERIALS AND METHODS

Twenty-two children with sickle cell disease and no history of stroke were evaluated by both TCD and TCDI. Examinations were performed on the same day without knowledge of the other modality results and read independently using manually obtained measurements. Mean velocities, peak systolic velocities, and end diastolic velocities obtained by the two techniques were compared. In a subgroup, manual measurements were compared to electronically obtained measurements.

RESULTS

TCDI values were lower than TCD measurements for all vessels. TCDI TAMMV values were most similar to the TCD values in the middle cerebral artery (-9.0%) and distal internal cerebral artery (-10.8%), with greater variability in the anterior cerebral artery (-19.3%), bifurcation (-16.3%), and basilar arteries (-23.1%). Risk group placement based on middle cerebral artery TAMMV values did not change when comparing the two techniques. Measurements obtained electronically were lower than those obtained manually.

CONCLUSION

Velocities obtained by TCDI may be lower than TCD measurements, and these differences should be taken into consideration when performing screening for stroke risk and selection for prophylactic transfusion based on the STOP protocol.