To meet grand challenges, agricultural scientists must engage in the politics of constructive collective action

Agriculture now faces grand challenges, with crucial implications for the global future. These include the need to increase production of nutrient-dense food, to improve agriculture's effects on soil, water, wildlife, and climate, and to enhance equity and justice in food and agricultural systems. We argue that certain politics of constructive collective action-and integral involvement of agricultural scientists in these politics-are essential for meeting grand challenges and other complex problems facing agriculture in the 21st century. To spur reflection and deliberation about the role of politics in the work of agricultural scientists, we outline these politics of constructive collective action. These serve to organize forceful responses to grand challenges through coordinated and cooperative action taken by multiple sectors of society. In essence, these politics entail (1) building bonds of affinity within a heterogenous network, (2) developing a shared roadmap for collective action, and (3) taking sustained action together. These emerging politics differ markedly from more commonly discussed forms of political activity by scientists, e.g., policy advisory, policy advocacy, and protest. We present key premises for our thesis, and then describe and discuss a politics of constructive collective action, the necessary roles of agricultural scientists, and an agenda for exploring and expanding their engagement in these politics.

THU0255 AUTOANTIBODY PROFILE AND ETHNICITY: RISK FACTORS FOR ACCELERATED DEVELOPMENT OF LUPUS NEPHRITIS

Background:

Systemic Lupus Erythematosus (SLE) is a multisystem autoimmune disease. African ancestry is associated with an increased risk of Lupus Nephritis (LN). Anti-DNA autoantibodies play a major role in the development of LN and anti-Ro antibodies have also been implicated. McCarty et al suggested that women of African ancestry with the unusual autoantibody combination of anti-Sm, Ro & RNP antibodies (AB) were at increased risk of developing LN (1).

Objectives:

Our aim was to determine the correlation between autoantibody profile: Sm, Ro and RNP as a combination in the development of LN in patients with African ancestry. We investigated time to the development of LN from SLE onset.

Methods:

A retrospective case-control study was conducted at Guys and St Thomas NHS Trust, London, United Kingdom.

75 patients with confirmed LN meeting the ACR classification criteria for SLE and Nephritis, were included: African (n=35), Caucasian (n=22) and Asian (n=17) ancestry. LN patients with the combination of Sm, Ro and RNP antibodies (Group 1) were compared to LN patients without this autoantibody combination (Group 2). Demographic data, pathology results and laboratory findings were collected.

Anonymised data was analyzed using Statistical Package for Social Sciences (SPSS). Left censorship bias was reduced by use of a database of confirmed LN in our cohort of patients. Research and Development Office approval was obtained for this study.

Results:

There were 66 (88%) females and 9 (12%) males. The median age in Group 1 was 39 years (range 18-60), while in group 2 the median age was 45 years (range 24-64).

We stratified our population based on their antibody status: Of the 75 (100%) patients, 32 (42.6%) patients had the combination of Sm, Ro & RNP antibodies (Group 1) while the remaining 43 (57.4%) patients did not (Group 2).

In Group 1, regardless of ethnicity, 29 (90.6%) patients developed LN within 5 years or less from the onset of SLE symptoms, while the remaining 3 (9.4%) developed LN after 5 years. In contrast, in Group 2, 24 (55.8%) patients developed LN within 5 years or less while 19 (44.2%) developed LN after 5 years. (P value = 0.002)

Further stratification was based on ethnicity and antibody (AB) status to investigate the time to develop LN from SLE symptom onset: African ancestry with positive AB, African with negative AB, Asian with positive AB, Caucasian with positive AB and Asian & Caucasian with negative Ab. Analysis showed that of 29 (38.7%) African ethnicity patients with the autoantibody combination, 19 (65.5%), developed LN within 5 years. In comparison, 46 (61.3%) patients, independent of ethnicity and AB status, developed LN after 5 years (P value = 0.01).

Conclusion:

Patients with the unusual autoantibody combination of Sm, Ro & RNP developed LN significantly earlier than patients who did not have this combination. This autoantibody combination was significantly over represented in the African ancestry patients. Our data suggests that African ancestry patients with this autoantibody combination are at increased risk of developing LN soon after SLE symptom onset and merit close monitoring for the development of renal disease.

References:

[1]McCarty GA, Harley JB, Reichlin M. A distinctive autoantibody profile in Black female patients with lupus nephritis. Arthritis & Rheumatism. 1993; 36:1560-1565

Table 1.1

Ethnicity with Autoantibody status showing the rate of progression into Lupus Nephritis.

Duration of LN onsetTotalLess than 5 years after SLE onsetMore than 5 years after SLE onsetEthnicity with AB statusAfrican with positive19322African with negative9413Asian with positive505Caucasian with positive505Other negatives151530Total532275Graph 1.

Ethnicity with Autoantibody status showing the rate of progression into Lupus Nephritis (P value= 0.01)

Disclosure of Interests:

Majed Albirdisi: None declared, David d’cruz Grant/research support from: GlaxoSmithKline, Shirish Sangle: None declared, Natasha Jordan: None declared

Spectroscopic evidence for selenium(IV) dimerization in aqueous solution

The aqueous speciation of selenium(iv) was elucidated by a combined approach applying quantum chemical calculations, infrared (IR), Raman, and (77)Se NMR spectroscopy. The dimerization of hydrogen selenite (HSeO3(-)) was confirmed at concentrations above 10 mmol L(-1) by both IR and NMR spectroscopy. Quantum chemical calculations provided the assignment of vibrational bands observed to specific molecular modes of the (HSeO3)2(2-) ion. The results presented will provide a better understanding of the chemistry of aqueous Se(iv) which is of particular interest for processes occurring at mineral/water interfaces.

Overexpression of L1CAM accompanies acquired endocrine resistance and is associated with the development of an aggressive cell phenotype

Abstract #3028

Background: Acquired resistance to endocrine therapies is associated with a gain in aggressive features in vitro which may impact on tumour spread in vivo. To identify potential candidate molecules which may promote this adverse cell behaviour, we performed microarray analysis on MCF-7 cell models of fulvestrant resistance ('FasR' cells) applying a commercial algorithm for signalling network discovery. We have subsequently investigated the significance of overexpression of L1CAM, a cell-surface adhesion molecule implicated in a MAPK signalling network and recently associated with tumour metastasis, in FasR cells and in clinical tissue.
 Materials and Methods: A network analysis algorithm was applied to t-test significant Affymetrix gene lists derived from FasR vs. MCF-7 cells (Almac Diagnostics). Subsequent to revealing a prominent L1CAM network, L1CAM gene and protein expression were assessed using RT-PCR, Western blotting and immunofluorescence. Inhibition of L1CAM was achieved using siRNA transfection. Cell invasion and migration were measured by seeding onto Matrigel- or fibronectin-coated microporous membranes respectively. After 48 hours, invasive/migratory cells were fixed, stained and counted. Analysis of cell signalling molecules was determined using Western blotting with phospho-specific antibodies. Clinical significance of L1CAM expression was determined by analysis of L1CAM expression in tumour (n=101) vs. normal (n=23) breast tissue using Q-PCR.
 Results: Development of fulvestrant resistance in MCF7 cells was associated with ER loss and a gain in migratory and invasive capacity in vitro. L1CAM was overexpressed at both gene (p<0.05) and protein (p<0.01) level in FasR cells whereas little or no L1CAM was detectable in MCF7 cells confirming microarray findings. Network and ontological analysis predicted L1CAM lies upstream of an ERK2 network (26 genes; p<0.0001) impinging on transcription factors/regulators which may promote aggressive cell behaviour. In agreement, siRNA-mediated inhibition of L1CAM suppressed the activity of nuclear MAP kinase and reduced the intrinsic migratory and invasive nature of FasR cells in vitro. Preliminary analysis indicated L1CAM expression was inversely associated with ER status (p<0.01) and reduced overall survival (p=0.01).
 Conclusions: These data suggest that L1CAM overexpression associates with emergence of ER-negative fulvestrant resistance in breast cancer, where it may confer a highly motile and invasive phenotype. Additionally, our clinical studies suggest L1CAM may also contribute to inherently aggressive, ER-negative breast cancers. L1CAM signalling may thus provide a new therapeutic target to subvert such aggressive states in vivo.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3028.

Environment. Sustainable development of the agricultural bio-economy

A U.S. farm policy shift to joint production of commodities and ecological services will advance sustainable agriculture.

Effectiveness of the dual specific Src/Abl kinase inhibitor AZD0530 in combination with tamoxifen in preventing acquired anti-estrogen resistance in breast cancer cells

14054

Background: AZD0530 is a novel, orally potent, once-daily, highly selective and dual-specific Src/Abl kinase inhibitor with potential for activity in a wide range of tumors. In the context of breast cancer, where tamoxifen resistance presents a major problem, Src inhibition may be a particularly valuable therapeutic strategy since we have previously observed that elevated Src kinase activity accompanies anti-estrogen resistance in vitro, promoting an aggressive cell phenotype. Here, we have explored the potential therapeutic effects of Src inhibition with AZD0530, alone and in combination with tamoxifen, on the acquisition of endocrine resistance in breast cancer cells. Methods: MCF7 and T47D breast cancer cells were exposed to tamoxifen (10–7 M), AZD0530 (1 μM), or both agents in combination for a minimum of 10 months with passaging as necessary, or until total cell death occurred. Cells were assayed at monthly intervals for intracellular signaling pathway activity (Western Blotting) and in vitro invasive capacity (Matrigel invasion assays). Apoptosis and proliferation were assessed by ELISA and Ki67 staining, respectively. Changes in c-Myc and cyclin-D1 were measured with RT-PCR. Results: Treatment of cells with tamoxifen alone ultimately resulted in acquired resistance, elevated Src kinase activity, and a Src- dependent increase in invasive capacity. Chronic exposure to AZD0530 alone resulted in outgrowth of AZD0530 resistant cells, in which Src kinase activity remained suppressed as did their in vitro invasiveness. Treatment of MCF7 and T47D cells with AZD0530 and tamoxifen combined resulted in a reduction of Src, FAK, and Akt activity, inhibition of c-Myc gene expression, and complete abrogation of their in vitro invasive behavior. Furthermore, combination treatment completely prevented cell proliferation and the subsequent emergence of a resistant phenotype, with a total loss of cells by 12 weeks. Conclusions: Inhibition of Src kinase with AZD0530, when used in conjunction with anti-estrogen therapies, effectively prevents acquired resistance in breast cancer cells in vitro suggesting a potential novel therapeutic benefit of Src kinase inhibitors clinically.

No significant financial relationships to disclose.

THE BLADDER DOES NOT APPEAR TO HAVE A DYNAMIC SECRETED CONTINUOUS MUCOUS GEL LAYER

PURPOSE

We determined whether the nature of any protective barrier in the bladder is composed of a secreted mucous gel layer.

MATERIALS AND METHODS

We collected 24-hour urine samples for analysis from 8 healthy 22 to 49-year-old volunteers and 5, 19 to 59-year-old patients treated with bladder reconstruction, in addition to scrapings from 100 freshly slaughtered pig bladders. Samples were subjected to homogenization, dialysis, freeze-drying, papain digestion, gel chromatography, equilibrium density gradient centrifugation, periodic acid-Schiff assay and amino acid analysis. Normal human bladder, pig bladder, normal ileum and transposed intestinal segments were studied for the presence of a mucous layer using a new method of histological analysis.

RESULTS

Mucin content in normal urine is 2.7 mg/24 hours, meaning that less than 0.6% of nondialyzable material in normal urine is mucin. The mucin content of urine from reconstructed bladders amounted to 86 mg/24 hours (5.2% of nondialyzable material). We observed that glycosaminoglycans accounted for 41% of the peak total elution volume of PAS positive material in normal urine. Mucin estimation in urine can be grossly overestimated if contaminating glycoconjugates are not removed. Biochemical analysis of material scraped off the pig bladder surface demonstrated that the maximum thickness of a continuous layer that could be achieved was 13.6 mum. While we could visualize an obvious mucous layer on control ileal samples and biopsies of transposed ileal segments from patients with bladder reconstruction, we were unable to note a distinct, measurable mucous layer lining the bladder surface in humans or pigs.

CONCLUSIONS

Mucin levels in normal human and pig urine would be enough for slow turnover of a thin barrier but the large increase in mucin in the urine of patients with transposed intestinal segments demonstrates that any layer in normal bladder is much different than that lining the transposed intestinal segment. The most likely constituents of this barrier are membrane bound rather than secreted mucins along with the proteoglycan components of the glycocalix.

The antiepidermal growth factor receptor agent gefitinib (ZD1839/Iressa) improves antihormone response and prevents development of resistance in breast cancer in vitro

Although many estrogen receptor-positive breast cancers initially respond to antihormones, responses are commonly incomplete with resistance ultimately emerging. Delineation of signaling mechanisms underlying these phenomena would allow development of therapies to improve antihormone response and compromise resistance. This in vitro investigation in MCF-7 breast cancer cells examines whether epidermal growth factor receptor (EGFR) signaling limits antiproliferative and proapoptotic activity of antihormones and ultimately supports development of resistance. It addresses whether the anti-EGFR agent gefitinib (ZD1839/Iressa; TKI: 1 mum) combined with the antihormones 4-hydroxytamoxifen (TAM: 0.1 mum) or fulvestrant (Faslodex; 0.1 mum) enhances growth inhibition and prevents resistance. TAM significantly suppressed MCF-7 growth over wk 2-5, reducing proliferation detected by immunocytochemistry and fluorescence-activated cell sorter cell cycle analysis. A modest apoptotic increase was observed by fluorescence-activated cell sorter and fluorescence microscopy, with incomplete bcl-2 suppression. EGFR induction occurred during TAM response, as measured by immunocytochemistry and Western blotting, with EGFR-positive, highly proliferative resistant growth subsequently emerging. Although TKI alone was ineffective on growth, TAM plus TKI cotreatment exhibited superior antigrowth activity vs. TAM, with no viable cells by wk 12. Cotreatment was more effective in inhibiting proliferation, promoting apoptosis, and eliminating bcl-2. Cotreatment blocked EGFR induction, markedly depleted ERK1/2 MAPK and protein kinase B phosphorylation, and prevented emergence of EGFR-positive resistance. Faslodex plus TKI cotreatment was also a superior antitumor strategy. Thus, increased EGFR evolves during treatment with antihormones, limiting their efficacy and promoting resistance. Gefitinib addition to antihormonal therapy could prove more effective in treating estrogen receptor-positive breast cancer and may combat development of resistance.

Adipose thyrotrophin receptor expression is elevated in Graves' and thyroid eye diseases ex vivo and indicates adipogenesis in progress in vivo

The thyrotrophin receptor (TSHR) provides an autoantigenic link between the thyroid and orbit in Graves' (GD) and thyroid eye diseases (TED). We measured TSHR transcripts in different fat depots to determine whether TSHR expression levels are influenced by the autoimmune/inflammatory process and/or thyroid hormone status, using quantitative real-time PCR. Nine intact or fractionated adipose samples, from patients with GD and/or TED, were analysed ex vivo. Eight expressed the TSHR, at levels approaching the thyroid, and one was at the limit of detection. Thirteen/fifteen orbital and abdominal fat samples from patients free of GD and TED, measured ex vivo, were negative for TSHR transcripts and two were at the limit of detection. All preadipocyte samples induced to differentiate in vitro expressed the TSHR. To investigate the influence of thyroid hormone status on adipose TSHR expression, we induced hyper- and hypothyroidism in BALBc mice by administering tri-iodothyronine and propylthiouracil respectively. In euthyroid animals, whole fat samples were at the limit of detection and were not altered by thyroid hormone status. The results show that adipose TSHR expression ex vivo indicates adipogenesis in progress in vivo and is associated with the autoimmune/inflammatory process in GD and TED but is not restricted to the orbit or influenced by thyroid hormone status.

The W546X mutation of the thyrotropin receptor gene: potential major contributor to thyroid dysfunction in a Caucasian population

Congenital hypothyroidism (CH) occurs in approximately 1 in 3000 births and can be caused by mutations in 9 known genes, including that encoding the TSH receptor (TSHR). We report on two Welsh siblings, detected by neonatal screening, who had normal sized and placed glands but negative isotope uptake. Genomic DNA was obtained from both siblings and parents, the TSHR amplified using pairs of intronic and/or overlapping exonic primers and the PCR products sequenced automatically. Both siblings were homozygous for a previously described G to A transition producing a missense mutation, W546X, in the fourth membrane spanning region of the TSHR, rendering it unresponsive to TSH. Both parents were heterozygous and unrelated; furthermore, the W546X has been described in three further families (one of which is Welsh), suggesting that it may be a relatively common mutation. We genotyped 368 euthyroid Welsh individuals using single nucleotide primer extension, and found 366 homozygous wild-type (G:G) and 2 heterozygous (G:A) for the mutation. In conclusion, CH in the siblings is due to the missense mutation, W546X, in their TSHR gene. The W546X allele was detected in approximately 1 in 180 individuals and may be a major contributor to hypothyroidism in the Welsh population.

Postmodern values, attitudes and the use of complementary medicine

OBJECTIVES

To examine the relationship between postmodern values, demographic variables and people's attitudes towards and use of acupuncture, aromatherapy and naturopathy.

DESIGN

One hundred and seventy-one adults completed a survey measuring postmodern values about health, attitudes towards and use of complementary and alternative medicine (CAM), age, gender, education, and current and recent health.

SETTING

Griffith University, Gold Coast, Australia.

MAIN OUTCOME MEASURES

Attitudes to CAM and use of CAM.

RESULTS

Postmodern values significantly predicted attitudes to CAM and actual use of CAM. Age also significantly predicted attitudes to CAM.

CONCLUSIONS

The results highlight the importance of patients' belief in natural remedies and in their active involvement in the healing process.

Impact of acid secretion, gastritis, and mucus thickness on gastric transfer of antibiotics in rats

BACKGROUND AND AIMS

The success of Helicobacter pylori eradication regimens depends on gastric pH, inflammation, and mucus thickness. Our aim was to investigate the effects of acid secretion, inflammation, and mucolysis on gastric antibiotic transfer.

SUBJECTS AND METHODS

A total of 134 anaesthetised rats were given metronidazole, amoxicillin, or clarithromycin intravenously and gastric contents were aspirated via an indwelling cannula. Acid secretion was controlled by either omeprazole or pentagastrin while gastritis was induced by infection with H pylori or dosing with iodoacetamide. Mucolysis was achieved by instilling pronase into the gastric lumen.

RESULTS

Metronidazole transfer increased with acid secretion and fell with omeprazole, independently of gastric pH. Clarithromycin was also transferred with acid but was then rapidly degraded. Omeprazole prevented this degradation, raising gastric luminal concentrations. Omeprazole did not alter amoxicillin transfer. Gastritis induced by H pylori did not alter gastric transfer of metronidazole and amoxicillin but that of clarithromycin was increased by 23%. However, gastritis induced by iodoacetamide reduced clarithromycin transfer without any effect on metronidazole or amoxicillin transfer. Pronase treatment increased amoxicillin transfer fourfold and metronidazole by 66% but reduced clarithromycin transfer by 35%.

CONCLUSIONS

Metronidazole and clarithromycin are predominantly transferred with gastric acid rather than by an acid trapping mechanism. Pronase increases the appearance of amoxicillin and metronidazole in gastric secretions.

Primary congenital glaucoma: three case reports on novel mutations and combinations of mutations in the GLC3A (CYP1B1) gene

PURPOSE

To describe three patients with congenital glaucoma homozygous and compound heterozygous for different mutations and benign sequence variants in the cytochrome P 450 1B1 (CYP1B1) gene.

METHODS

All patients were examined by slit-lamp biomicroscopy, gonioscopy, measurement of the cornea and optic disc, ultrasound biometry, and automated static threshold perimetry when possible. Direct sequence analysis was performed on DNA extracted from peripheral blood from the patients and their parents.

RESULTS

For patient 1, a newborn boy with buphthalmos and an opaque cornea, a novel homozygous C/T transition in codon 355 (CGA>TGA) led to a predicted nonsense codon Arg355X truncating the protein by 188 amino acids. For patient 2, a 24-year-old man, a compound heterozygous mutation 1410-1422del/1546-1555dup was found. For patient 3, a 34-year-old man, two novel heterozygous missense mutations resulting in an Ala443Gly and a Glu229Lys amino acid exchange and five benign sequence variants were found.

CONCLUSION

Our results confirm the crucial role of CYP1B1 mutations for congenital glaucoma.

Sequence and analysis of chromosome 3 of the plant Arabidopsis thaliana

Arabidopsis thaliana is an important model system for plant biologists. In 1996 an international collaboration (the Arabidopsis Genome Initiative) was formed to sequence the whole genome of Arabidopsis and in 1999 the sequence of the first two chromosomes was reported. The sequence of the last three chromosomes and an analysis of the whole genome are reported in this issue. Here we present the sequence of chromosome 3, organized into four sequence segments (contigs). The two largest (13.5 and 9.2 Mb) correspond to the top (long) and the bottom (short) arms of chromosome 3, and the two small contigs are located in the genetically defined centromere. This chromosome encodes 5,220 of the roughly 25,500 predicted protein-coding genes in the genome. About 20% of the predicted proteins have significant homology to proteins in eukaryotic genomes for which the complete sequence is available, pointing to important conserved cellular functions among eukaryotes.

The adherent gastric antral and duodenal mucus gel layer thins with advancing age in subjects infected with Helicobacter pylori

BACKGROUND

Peptic ulceration and Helicobacter pylori infection increase with advancing age. In the upper gastro-intestinal tract the first line of mucosal defence is the adherent mucus gel layer.

OBJECTIVE

We have examined, using a novel histological fixation technique, the thickness of the adherent mucus gel layer (1) in the gastric antrum and (2) in the duodenum in relation to advancing age and H. pylori status.

METHODS

The subjects had macroscopically normal stomach and duodenum at endoscopy. Measurement of the gastric antral mucus thickness was carried out on four antral biopsy specimens from within 2 cm of the pylorus (H. pylori positive n = 25, negative n = 21). The duodenal mucus thickness (D1) was measured from two biopsy specimens (H. pylori positive n = 7, negative n = 13). All specimens were snap frozen and cryostat sections stained using a modified PAS/AB stain.

RESULTS

In all sections the mucus layer was continuous. In both duodenum and gastric antrum, the mucus thickness was not significantly different between H. pylori positive and H. pylori negative age-matched samples. In duodenum and gastric antrum from H. pylori negative subjects, there was no correlation between mucus thickness and age. However, in H. pylori positive subjects, there was a significant thinning of the adherent gastric antral mucus gel layer (p = 0.005, r = -0.54) and the duodenal mucus thickness (p<0.001, r = -0.99) with advancing age.

CONCLUSION

This study shows a significant thinning of the adherent mucus gel layer in H. pylori positive individuals, as stomach and duodenum age. In those without H. pylori, the mucus gel thickness is preserved in stomach and duodenum.

Effects on blood pressure of drinking green and black tea

BACKGROUND

The flavonoid components of tea have been associated in epidemiological studies with a decreased risk of cardiovascular disease. Flavonoids have been shown to have antioxidant and vasodilator effects in vitro; we therefore postulated that drinking green or black tea attenuates the well-characterized acute pressor response to caffeine and lowers blood pressure during regular consumption.

OBJECTIVE

To determine whether green and black tea can attenuate the transient pressor effect of caffeine, or lower blood pressure during regular consumption.

METHODS

In the first study, the acute effects of four hot drinks - green tea and black tea (at a dose equivalent to four standard cups), water matched to the teas for caffeine content ('caffeine') and water - were assessed in 20 normotensive men using a Latin-Square designed study. Clinic blood pressure was measured before and 30 and 60 min after each drink had been ingested. In the second study, the effects on blood pressure of regular green and black tea ingestion were examined in 13 subjects with high-normal systolic blood pressure and mild systolic hypertension (systolic blood pressure in the range 130-150 mmHg) using a three-period crossover study. Five cups per day of green tea, black tea and caffeine (in hot water and matched to the teas) were consumed for 7 days each, in random order. Twenty-four hour ambulatory blood pressure was measured at the end of each seven-day intervention. Results are presented as means and 95% confidence intervals (CI).

RESULTS

An acute pressor response to caffeine was observed. Relative to caffeine, there were further acute increases in systolic and diastolic blood pressure at 30 min among those drinking green tea [5.5 mmHg (95%CI -1.4 to 12.4) and 3.1 mmHg (95%CI -0.1 to 6.3), respectively] and black tea [10.7 mmHg (95%CI 4.0 to 17.4) and 5.1 mmHg (95%CI 1.8 to 8.4), respectively]. The changes in blood pressure at 60 min were not significant The effect on 24-h ambulatory systolic and diastolic blood pressure of regular drinking of green tea [increases of 1.7 mmHg (95%CI -1.6 to 5.0) and 0.9 mmHg (95%CI -1.3 to 3.1), respectively] or black tea [increase of 0.7 mmHg (95%CI -2.6 to 4.0) and decrease of 0.7 mmHg (95%CI -2.9 to 1.5), respectively] was not significant relative to caffeine.

CONCLUSIONS

Contrary to our initial hypothesis, tea ingestion caused larger acute increases in blood pressure than caffeine alone. However, any acute effects of tea on blood pressure did not translate into significant alterations in ambulatory blood pressure during regular tea consumption.

Goals for Alzheimer's care in nursing homes: what kind of differences do special care units expect to make?

Special Care Units (SCUs) for people with dementia have been enthusiastically promoted although many residents with dementia live elsewhere in their nursing home. In response to open-ended questions during personal interviews, coordinators of all 64 SCUs in Minnesota nursing homes described their goals and criteria for success. They then rated the importance of a list of possible goals and their unit's success in achieving them. Unit coordinators of 173 nursing home units in facilities with SCUs and 135 units in facilities without SCUs answered the same questions about people with dementia in their own units. When unprompted, respondents both in and outside SCUs were varied, sparse (averaging 3.1 goals per person), vague, process-oriented rather than outcome-oriented, and sometimes unrealistic. Yet, respondents later strongly endorsed most of the 24 goals the researchers suggested. ANOVA and regression analyses revealed few statistically significant differences according to unit type, although SCU coordinators were more likely to aspire to fewer medications, reduced disruptive behavior, and reduced agitation and anxiety, and were less likely to want residents to sleep through the night. Some differences were only between SCUs and non-SCUs in facilities without SCUs. Characteristics of facilities, coordinators, and case mix (e.g., proportion of dementia on the unit) were as predictive of goals and perceptions of success as SCU units. Findings reinforce the lack of conceptual clarity about expectations for direct and indirect effects of SCUs.

Helicobacter pylori in vivo causes structural changes in the adherent gastric mucus layer but barrier thickness is not compromised

BACKGROUND

It has been proposed that a pathogenic effect of Helicobacter pylori is a weakening of the protective mucus barrier; however, this remains controversial.

AIMS

To clarify the effects of H pylori infection on the mucus gel barrier in vivo.

METHODS

Mucus gel polymeric structure and the thickness of the adherent mucus barrier were measured in endoscopic biopsy samples in subjects with and without H pylori infection.

RESULTS

There was a significant 18% reduction in the proportion of polymeric gel forming mucin in the adherent mucus layer in H pylori positive compared with negative subjects. There was no change in the adherent mucus thickness between H pylori positive and negative subjects without gastric atrophy (mean (SD): 104 (26) micron, 106 (30) micron, respectively). There was however a significant reduction in mucus thickness in those H pylori positive subjects with underlying gastric atrophy (84 (13) micron, p=0.03) compared with those without atrophy.

CONCLUSIONS

A partial breakdown in gel forming structure of the gastric mucus barrier does occur in H pylori infection per se but this is insufficient to cause a collapse of the mucus barrier.

A novel method for the visualization of the in situ mucus layer in rat and man

1. The observed thickness of the gastric mucus barrier varies widely, even appearing discontinuous, depending on the methods used. Here we describe the development and application of a modified periodic acid Schiff/Alcian Blue staining technique for use on cryostat sections of gastric mucosa. This technique for the first time enables the preservation and visualization of the full thickness of the adherent gastric mucus layer and the underlying mucosa. 2. In designing this novel method we have selected those procedures which would result in the least alteration to the mucus layer. The methods used were snap freezing, cryostat sectioning of the whole stomach followed by brief ethanol pretreatment (10 min in 100% ethanol), a prolonged staining with periodic acid Schiff/Alcian Blue (15 min and 2.5 h respectively), a gentle post-fixation (45 min paraformaldehyde vapour at 37 degreesC) and the use of a water-soluble mountant. 3. A continuous, adherent mucus layer was observed over the surface of the rat gastric mucosa (periodic acid Schiff/Alcian Blue stained) and human gastric antral biopsies (periodic acid Schiff stained). In the rat the mean (S.D.) mucus thickness measurements along the antrum to oesophageal axis (which was divided histologically into four regions, A to D) were: A, 166 (47) micrometer; B, 179 (48) micrometer; C, 184 (50) micrometer; D (the non-glandular stratified epithelium at the top of the stomach), Absent. In human gastric antral biopsies the mean (S.D.) mucus thickness was 144 (52) micrometer. 4. This new technique has enabled the visualization and precise measurement of thickness of the gastric mucus layer in rat and man. The adherent gastric mucus layer was observed to be continuous in the rat glandular stomach and human antrum. In validation experiments in rat the mean mucus thickness measurements were found to be twice those measured by conventional histological techniques, in which the mucus layer appeared discontinuous and patchy. However, they were within the range of thickness values seen in unfixed tissues and in the rat in vivo preparation.

Sexually transmitted diseases in Ulaanbaatar, Mongolia

Although human immunodeficiency virus (HIV) rates are increasing rapidly in Asia, a full understanding of the extent of other sexually transmitted diseases (STDs) in many of these areas is lacking. There have been anecdotes of rising rates of STDs in Mongolia, a country thus far relatively unaffected by HIV. To further the understanding of STDs, a prevalence study was conducted in the STD clinic in Ulaanbaatar, the capital and largest city in Mongolia. Among 260 patients, the prevalence of gonorrhoea, chlamydia and syphilis was 31.1%, 8.1% and 8.6% respectively for males and 10.3%, 9.9% and 6.0% for females. Sixty-seven per cent of females had trichomoniasis and 19.7% of males had non-gonococcal urethritis (NGU). Forty-two per cent of gonococcal isolates had plasmid mediated resistance to penicillin, and chromosomal resistance to penicillin, tetracycline, and ciprofloxacin was documented. No patients were infected with HIV. STDs are a significant problem in Mongolia. Improved control efforts are urgently needed to prevent the emergence of HIV.

Mucus and H. pylori

A continuous, adherent mucus gel layer with mucosal bicarbonate secretion is the initial protective barrier in the stomach and duodenum against erosion by the gastric juice. H. pylori resides within the adherent mucus gel layer close to the epithelial surface. The barrier function of the mucus layer in vivo depends on (i) its thickness, and (ii) its gel structure, a property which is linearly dependent on the polymeric mucin content. We have shown in vivo that H. pylori colonisation alone did not decrease the thickness of the adherent gastric mucus barrier, although there was a mean 20% decrease in mucus thickness in those H. pylori positive subjects with underlying gastric atrophy. There was, however, a significant mean 18% reduction in the gel-forming polymeric mucin content of mucus from H. pylori subjects, independent of underlying atrophy. Studies in vitro suggest this loss of gel structure might arise from a H. pylori mediated, high local pH generated by urease activity rather than by proteolysis. This study shows that H. pylori infection alone does not compromise the overall integrity of the mucus barrier in vivo. However, in the immediate environment of the organism there appears to be a localised loss of mucus gel structure. The mucus barrier is compromised if H. pylori associated gastric atrophy or peptic ulceration follows.

Effectiveness and economic impact of antidepressant medications: a review

This article reviews the existing literature on the pharmacoeconomics and effectiveness of antidepressant medications. Although selective serotonin reuptake inhibitors (SSRIs) have not proved to be more efficacious than the older tricyclics, and their prescription costs are significantly higher, they provide superior effectiveness; ie, patients are less likely to discontinue taking them or switch antidepressants. Pharmacoeconomic studies consistently demonstrate a relationship between this superior effectiveness and reductions in overall treatment costs, often through decreased utilization of medical and hospital services. The most conservative study found a cost offset that more than negated the extra cost of drugs, although the cost savings were not statistically significant. Other studies found statistically significant lowering of utilization costs by using SSRIs rather than tricyclics. Studies comparing SSRIs with each other present conflicting findings, although fluoxetine appears to have an edge over sertraline and paroxetine with regards to effectiveness and pharmacoeconomics. More studies employing a prospective outcome design and naturalistic study setting need to be conducted with SSRIs and other new antidepressants.

The reinforcing effects of brief exposures to nitrous oxide in healthy volunteers

The reinforcing and subjective effects of brief (about 1.5 min) exposures to nitrous oxide, ranging from inspired concentrations of 20-80% in oxygen, were examined in 11 healthy volunteers. A choice procedure was used in which during each of four sessions, subjects first sampled a given concentration of nitrous oxide and placebo oxygen, and then chose between the two. 20, 40, 60 and 80% nitrous oxide were chosen by five, four, three, and three subjects, respectively--these choice levels did not exceed that of chance. All concentrations had psychoactive effects, and in general, concentration-related subjective effects were found. We conclude that in a medical setting, nitrous oxide inhaled in a manner similar to that when used recreationally in a naturalistic setting, does not function as a reinforcer across a wide range of concentrations, in subjects with a modest lifetime history of psychoactive drug use.

Interleukin 10 (IL-10) regulation of tumour necrosis factor alpha (TNF-alpha) from human alveolar macrophages and peripheral blood monocytes

BACKGROUND

Regulation of the inflammatory response within the human lung is essential to prevent this important part of the normal host defence response becoming a pathological process. Tumour necrosis factor alpha (TNF-alpha) is a cytokine involved in the pathogenesis of shock and in granuloma formation, tissue necrosis, and fibrosis in many organ systems including the lung. Interleukin 10 (IL-10) has been proposed as having an inhibitory effect on the production of several inflammatory cytokines including TNF-alpha.

METHODS

The effect of IL-10 administration on TNF-alpha production was explored in human alveolar macrophages and peripheral blood monocytes from matched individuals. The effects of IL-10 on TNF-alpha protein production were determined by sandwich enzyme linked immunosorbant assay (ELISA), whereas the TNF-alpha mRNA response was established by Northeren blotting using a TNF-alpha specific oligonucleotide probe. The protein synthesis inhibitors actinomycin D and cyclohexamide were utilised to monitor IL-10 effects on mRNA degradation and de novo protein synthesis, respectively.

RESULTS

The lipopolysaccharide-mediated TNF-alpha production in alveolar macrophages was reduced from 3.508 (0.629) to 2.035 (0.385) ng/ml by 100 U/ml IL-10. Lipopolysaccharide-induced TNF-alpha production in peripheral blood monocytes was reduced from 2.035 (0.284) to 0.698 (0.167) ng/ml. TNF-alpha gene expression was also inhibited in both alveolar macrophages and peripheral blood monocytes; lipopolysaccharide-induced TNF-alpha mRNA was reduced by 47.8 (15.2)% and 83.1 (4.2)%, respectively, by IL-10. The IL-10 mediated suppression of TNF-alpha mRNA was unaffected by addition of cyclohexamide, suggesting that de novo protein synthesis was not required for TNF-alpha inhibition. mRNA stability experiments indicated no acceleration in lipopolysaccharide-induced TNF-alpha mRNA degradation in response to IL-10.

CONCLUSIONS

These findings suggest that IL-10 is a potent inhibitor of TNF-alpha expression and release from alveolar macrophages and peripheral blood monocytes, and thus it may have an important role in the cytokine network of the pulmonary immune response.

The role of the striatum in motor learning: dissociations between isometric motor control processes in Parkinson's disease

Studies of Parkinson's disease (PD) have been used to support the hypothesis that the striatum serves procedural learning but interpretation of the results is confounded by extra-striate pathology and coincidental non-procedural cognitive deficits. The motor deficit of PD involves particularly internally cued movement, without visual feedback, because of disruption to frontostriatal circuits. Thus, we used a non-visual isometric task as a sensitive measure of motor learning in early non-demented patients with PD and examined the effects of dopamine replacement. The PD group showed disproportionate under-shooting of the target but normal motor learning. Learning correlated with some cognitive measures but not clinical motor disability or depression. Treatment had no effect on performance, despite clinical improvement. The results indicate dissociations between motor control processes resulting from striatal pathology. Putaminal circuits are involved in force generation and prediction but not critically in motor learning.

Slowed central processing in simple and go/no-go reaction time tasks in Parkinson's disease

Studies of cognition and motor control have independently suggested that patients with Parkinson's disease show deficits in both attentional control and the preprogramming of movement. However, few studies have examined directly the involvement of cognitive processes in the origin of their slowed response. We examined the performance of 100 Parkinson's disease patients on simple reaction time (SRT) and a series of go/no-go cross-modality choice reaction time (CRT) tasks, in which motor response was constant; correct positive responses required attention to a progressively increasing number of dimensions of visual and auditory stimuli. The results showed that Parkinson's disease patients became increasingly impaired in response speed as choice complexity increased. Slowed response speed in Parkinson's disease involved two factors: (i) a 'perceptuomotor' factor which was constant across conditions and independent of choice complexity. Depression affected this factor selectively and independently of confounding associations with impoverished motor control; (ii) a 'cognitive-analytical' factor, which played an increasingly important role as complexity of choice increased. The characteristics of the relationship between response latency and cognitive complexity indicate that the deficit was due to a constant proportional slowing in cognitive speed across all SRT and CRT conditions. A cognitive deficit affecting the monitoring of stimulus-response compatibility may contribute to delayed response in Parkinson's disease. This cognitive-analytical deficit is present in early, untreated cases and, in contrast to perceptuomotor processes, is weakly related to depression.