Environmental contamination and detection of Salmonella enterica serovar enteritidis in laying flocks

Faecal, dust and other environmental samples were collected from the floors, droppings belts, egg-collection systems and other areas of 14 cage-layer flocks, 10 barn egg production flocks and seven free-range flocks, and cultured for Salmonella species. The distribution of the organism varied with its prevalence and with the vaccination status of the birds. No one sample type was found to be suitable for identifying all contaminated houses. Salmonella was also frequently found on egg-packing equipment and in samples from rodents and wild birds.

Comparative investigations of the desensitising efficacy of a new dentifrice

OBJECTIVES

In two clinical trials of 8 weeks duration, the ability of a new dentifrice, containing potassium nitrate, stannous fluoride and sodium fluoride to reduce dentine hypersensitivity was compared with either a non-desensitising fluoride dentifrice or a commercially available desensitising dentifrice (Sensodyne F) to reduce dentine hypersensitivity.

METHOD

In both studies, the participants had to have at least two sensitive root surfaces. Subjects were stratified by baseline tactile and air blast sensitivity scores and the number of sensitive teeth and randomly allocated to 2 balanced groups. In the first study (N=81) the new dentifrice was compared with a fluoride dentifrice and in the second study (N=105) with Sensodyne F. Participants were requested to brush with their assigned dentifrice twice a day for one minute. At 4 and 8 weeks the sensitive teeth were again examined and their tactile and air blast sensitivity scores recorded.

RESULTS

In study 1, the group using the new dentifrice tolerated greater pressure after 4 (34.9 g) and 8 weeks (38.4 g) than the group using the fluoride dentifrice (22.9 g and 19.0 g, respectively). These differences were statistically significant (p<0.001). At 4 and 8 weeks, the mean air blast scores for the group using the new dentifrice (1.39 and 0.83) were lower than for the group using fluoride dentifrice (1.78 and 1.76) and were significantly different at 8 weeks (p<0.001). In study 2 the group using the new dentifrice tolerated greater pressure after 4 (40.5 g) and 8 weeks (43.7 g) than the group using Sensodyne F (27.8 g and 33.2 g, respectively). These differences were statistically significant (p<0.001). At 4 and 8 weeks, the mean air blast scores for the group using the new dentifrice (1.10 and 0.67) were significantly lower than the group using Sensodyne F (1.90 and 1.57) (p<0.001).

CONCLUSIONS

These studies demonstrate that the new dentifrice, containing potassium nitrate, stannous fluoride and sodium fluoride is significantly better at reducing dentine hypersensitivity than both the dentifrice containing sodium fluoride and the one containing potassium chloride, triclosan and sodium fluoride (Sensodyne F).

Delayed effects of tamoxifen in hepatocarcinogenesis-resistant Fischer 344 rats as compared with susceptible strains

The anti-oestrogenic drug tamoxifen has been under investigation as a breast cancer chemopreventive agent for at least a decade. However, its use for this purpose is still debatable since it is able to induce liver tumours in rats via a mechanism involving metabolic activation to a DNA adduct-forming electrophilic intermediate. The metabolic activation and adduct-forming properties of tamoxifen are now well characterized but less is known about its ability to induce hepatic cell proliferation, which is also essential for the carcinogenic process. The effects of tamoxifen on liver weight and cell proliferation were compared in female Fischer 344 (F344), Wistar and Lewis rats given the drug in the diet for up to 26 weeks. The onset and duration of hepatic cell proliferation varied between the strains of rat. In Wistar and Lewis but not F344 rats there was a marked increase in hepatocellular proliferation during the first 4 weeks of tamoxifen administration. In the Wistar strain this was associated with an increase in DNA adduct levels; no such increase was observed in the F344 strain. The onset of the proliferative response was delayed until the 13 week time point in the F344 strain. By the 13 and 26 week time points, cell proliferation in tamoxifen-treated Wistar and Lewis rat liver had returned to normal, but the amount of apoptotic activity in these livers was elevated. This suggests that excess cells generated during the proliferative phase of tamoxifen treatment were being eliminated by apoptosis. In the F344 strain, however, increased proliferative activity was associated with relatively low apoptotic activity at the 26 week time point, suggesting that the delayed proliferative response had yet to be balanced by apoptotic deletion. This is consistent with the fact that tamoxifen-induced hepatocellular tumours develop very late, towards the end of the lifespan, in this strain. The cell proliferative activity of tamoxifen in the Wistar rat liver was compared with that of a non-mutagenic analogue, toremifene. Tamoxifen induced increased cell cycle activity in the livers of rats following gavage dosing at all sampling times (1-12 weeks), whereas toremifene had no effect on the incidence of cycling in hepatic cells, demonstrating that the hepatic cell proliferation is not a general response to anti-oestrogen treatment. These observations suggest that the rate of promotion of liver tumours by tamoxifen is a function of the rate, time of onset and duration of increased cell replication. The susceptibility of rat strains to the hepatocarcinogenic effects of tamoxifen appears to depend upon the balance between initiation via DNA adduct formation, promotion via increased cell proliferation and cell deletion via apoptosis. Our findings suggest that an early proliferative response to tamoxifen is important in this process.

Maintaining contact with people with severe mental illness: 5-year follow-up of assertive outreach

BACKGROUND

Assertive outreach is a central strand of Government mental health policy in England. Are different long-term models of mental health care which include assertive outreach associated with different service user outcomes and cost?

METHOD

We conducted a multi-site 5-year follow-up study of people with severe mental illness. From 0 to 18 months all three sites had Intensive Case Management (ICM) teams practising assertive outreach. From 18 to 60 months one team sustained ICM, one team merged and another was disbanded. All 131 original ICM team clients were the study participants. Outcome was measured in terms of sustained engagement with statutory mental health services, psychiatric symptoms, social functioning, resource use and cost.

RESULTS

All 120 live participants were traced. Only four people had no service contact; when contacted by a researcher they appeared to be coping well. No incidents of serious violence were discovered. No differences existed between teams in the mean total symptom or total social functioning change scores at follow-up, after controlling for baseline differences. No differences existed in mean cost between teams during the first 18 months. Mean (standard deviation) annualised costs varied considerably in the 18-60 month period: sustained team Pound Sterling13,734 (10,820); integrated team Pound Sterling11,037 (13,603); disbanded team Pound Sterling5,742 (7,007) (F=4.4, 105 df, p=0.015).

CONCLUSION

Continued specialist assertive outreach service models have higher costs than non-specialist services for no apparent benefit. In the long term new assertive outreach services should have procedures in place to transfer people to lower intensity and lower cost care.

Observations on the distribution and control of Salmonella species in two integrated broiler companies

The effectiveness of cleaning and disinfecting broiler farms and the persistence of Salmonella species in two integrated broiler companies was investigated for two years. Both companies used a cleaning and disinfection regime which included the application of a spray of phenolic disinfectant followed by fogging with formaldehyde solution, and this was highly effective in preventing carry-over of infection in the broiler houses. The disinfection of service areas and areas outside the houses was less effective but it had no influence on the Salmonella status of later flocks. Both companies had persistent problems with the contamination of pellet cooling systems in their feedmills with Salmonella 4, 12:d:- in company A, and with Salmonella binza and Salmonella ohio in company B. The hatcher incubators of both companies were also persistently contaminated with Salmonella livingstone and Salmonella thomasville in company A and with Salmonella senftenberg in company B. At both companies sites Salmonella enteritidis and Salmonella typhimurium Tr104 were also isolated occasionally from various locations.

A six-week clinical tooth whitening study of a new calculus-inhibiting dentifrice formulation

This six-week double-blind clinical study compared the toothwhitening effects of a new calculus-inhibiting dentifrice containing pyrophosphate, tripolyphosphate and copolymer in a 0.243 sodium fluoride/silica base (Test Dentifrice) with two commercially available dentifrices: Aquafresh Whitening Toothpaste with Fluoride and Crest Regular Fluoride Toothpaste. After a baseline examination for extrinsic tooth stain, qualifying adult males and females from Manchester, United Kingdom and from Mississauga, Ontario, Canada were randomly assigned into three test groups. Each group was balanced for gender, tobacco habits and levels of tooth stain. Subjects were to brush their teeth twice daily with a soft-bristled toothbrush using the assigned toothpaste. One-hundred and twenty-eight (128) subjects complied with instructions and completed the trial. Subjects using the Test Dentifrice exhibited statistically less stain area and less stain intensity than did either the Aquafresh or Crest groups. Crest Regular Fluoride toothpaste was statistically less effective than Aquafresh Whitening toothpaste in removing stain. Results in this trial support the conclusion that a new dentifrice formulation containing pyrophosphate, tripolyphosphate and a copolymer, in a 0.243% sodium fluoride/silica base, effectively removes extrinsic tooth stain.

Genetics of human complement component C4 and evolution the central MHC

The two classes of human complement component C4 proteins C4A and C4B manifest differential chemical reactivities and binding affinities towards target surfaces and complement receptor CR1. There are multiple, polymorphic allotypes of C4A and C4B proteins. A complex multiplication pattern of C4A and C4B genes with variations in gene size, gene dosage and flanking genes exists in the population. This is probably driven by the selection pressure to respond to a great variety of parasites efficiently and effectively, which the bony fish achieved through the multiplication and diversification of the related complement C3 proteins. Complement C4, C3 and C5 belong to the alpha2 macroglobulin protein family but acquired specific features that include an anaphylatoxin domain, a netrin (NTR) domain, and stretches of basic residues for proteolytic processings to form multiple chain structures. Complement C3 and C4 are important in the innate immune response as they opsonize parasites for phagocytosis. The emergence of complement C3 predates proteins involved in the adaptive immune response as C3 is present in deuterostome invertebrates such as echinoderms. The human C4 genes are located in the central MHC at chromosome 6p21.3. C3 and C5 are located at chromosome 19 and 9, respectively, with representatives of the other groups of genes paralogous to the MHC at 19p13.1-p13.3, 1q21-25, and 9q33-34. The central MHC also contains genes for complement components C2 and Bf. These genes appear to have similar evolutionary histories to C3/C4/C5 and are used here to illustrate stepwise processes resulting in co-location of diverse domains, chromosomal duplication, local segmental duplication and divergence of sequence and function. This model of evolution is useful in the investigation of innate and acquired immunity and in seeking explanations for diseases associated with MHC ancestral haplotypes.

Interference between postural control and mental task performance in patients with vestibular disorder and healthy controls

OBJECTIVES

To determine whether interference between postural control and mental task performance in patients with balance system impairment and healthy subjects is due to general capacity limitations, motor control interference, competition for spatial processing resources, or a combination of these.

METHOD

Postural stability was assessed in 48 patients with vestibular disorder and 24 healthy controls while they were standing with eyes closed on (a) a stable and (b) a moving platform. Mental task performance was measured by accuracy and reaction time on mental tasks, comprising high and low load, spatial and non-spatial tasks. Interference between balancing and performing mental tasks was assessed by comparing baseline (single task) levels of sway and mental task performance with levels while concurrently balancing and carrying out mental tasks.

RESULTS

As the balancing task increased in difficulty, reaction times on both low load mental tasks grew progressively longer and accuracy on both high load tasks declined in patients and controls. Postural sway was essentially unaffected by mental activity in patients and controls.

CONCLUSIONS

It is unlikely that dual task interference between balancing and mental activity is due to competition for spatial processing resources, as levels of interference were similar in patients with vestibular disorder and healthy controls, and were also similar for spatial and non-spatial tasks. Moreover, the finding that accuracy declined on the high load tasks when balancing cannot be attributed to motor control interference, as no motor control processing is involved in maintaining accuracy of responses. Therefore, interference between mental activity and postural control can be attributed principally to general capacity limitations, and is hence proportional to the attentional demands of both tasks.

Total synthesis of himandravine

[reaction: see text] The first total synthesis of (+)-himandravine (1) is described, starting from (2S,6S)-cis-2-formyl-6-methyl-N-Boc-piperidine (8) in 11 linear steps and 17% overall yield. The key step involves a highly diastereoselective intramolecular Diels-Alder reaction of the key intermediate 5 that contains the entire latent carbon framework and functional group substitution of himandravine.

Early Oligocene initiation of North Atlantic Deep Water formation

Dating the onset of deep-water flow between the Arctic and North Atlantic oceans is critical for modelling climate change in the Northern Hemisphere and for explaining changes in global ocean circulation throughout the Cenozoic era (from about 65 million years ago to the present). In the early Cenozoic era, exchange between these two ocean basins was inhibited by the Greenland-Scotland ridge, but a gateway through the Faeroe-Shetland basin has been hypothesized. Previous estimates of the date marking the onset of deep-water circulation through this basin-on the basis of circumstantial evidence from neighbouring basins-have been contradictory, ranging from about 35 to 15 million years ago. Here we describe the newly discovered Southeast Faeroes drift, which extends for 120 km parallel to the basin axis. The onset of deposition in this drift has been dated to the early Oligocene epoch ( approximately 35 million years ago) from a petroleum exploration borehole. We show that the drift was deposited under a southerly flow regime, and conclude that the initiation of deep-water circulation from the Norwegian Sea into the North Atlantic Ocean took place much earlier than is currently assumed in most numerical models of ancient ocean circulation.

The relationship between atopic status and IL-10 nasal lavage levels in the acute and persistent inflammatory response to upper respiratory tract infection

We examined the influence of atopy on virus-induced airway inflammation by comparing the nasal response to naturally acquired upper respiratory tract infection in atopic and nonatopic subjects by measurement of cytokine, chemokine, and mediator levels in nasal lavage from 44 adults (23 atopic) taken during the acute and the convalescent phases of the common cold. Nasal aspirates were examined for the presence of upper respiratory viruses by RT-PCR. In atopic and nonatopic subjects there were increased levels of IL-1beta, IL-6, IL-8, TNF-alpha, RANTES, sICAM-1, MPO, ECP, IL-10, and IFN-gamma in nasal lavage during the acute compared with the convalescent phase (p < 0.001). During the acute phase histamine levels were significantly higher in the atopic than in the nonatopic subjects (p < 0.05), whereas IL-10 levels were significantly greater in the nonatopic than in the atopic subjects (p < 0.05). At convalescence levels of IL-1beta, IL-6, sICAM-1, ECP, RANTES and albumin were significantly higher in the atopic group (p < 0.05). An upper respiratory tract virus was found in 27 volunteers (61%) during the acute stage and in two volunteers (4%) at convalescence. We conclude that virus-induced inflammatory changes within the nose are more prolonged in atopic than in nonatopic subjects and that this is associated with reduced IL-10 levels in atopic compared with nonatopic subjects during the acute phase of upper respiratory tract infection.

Short-term dosing of alpha-hydroxytamoxifen results in DNA damage but does not lead to liver tumours in female Wistar/Han rats

It is now generally accepted that activation of tamoxifen occurs as a result of metabolism to alpha-hydroxytamoxifen. In this study, alpha-hydroxytamoxifen was given to female Wistar/Han rats (0.103 or 0.0103 mmol/kg, intraperitoneally, daily for 5 days). This resulted in liver DNA damage, determined by (32)P-post-labelling, of 3333 +/- 795 or 343 +/- 68 adducts/10(8) nucleotides, respectively (mean +/- SD, n = 4). Following HPLC separation, the retention times of the major alpha-hydroxytamoxifen DNA adducts were similar to those seen following the administration of tamoxifen. However, after rats were treated with alpha-hydroxytamoxifen (0.103 mmol/kg) for 5 days and the animals kept for up to 13 months, no liver tumours developed (0/7 rats), even with phenobarbital promotion (0/5 rats). GST-P foci were detected in the liver, but only after 13 months was their number or area significantly increased over the corresponding controls. When alpha-hydroxytamoxifen was given to female lambda/lacI transgenic rats (0.103 mmol/kg orally for 10 days) and the animals killed 46 days later, there was an approximate 1.8-fold increase in mutation frequency but no significant increase in G:C to T:A transversions as described after tamoxifen treatment. It is concluded that DNA damage alone, resulting from the short-term administration of alpha-hydroxytamoxifen, is not sufficient to initiate liver tumours even with phenobarbital promotion. As with tamoxifen, long-term exposure may be required to allow promotion and progression of transformed cells.

Gene expression and amplification in breast carcinoma cells with intrinsic and acquired doxorubicin resistance

The multidrug resistance (MDR) phenotype is a major cause of cancer treatment failure. Here the expressions of 4224 genes were analysed for association with intrinsic or acquired doxorubicin (DOX) resistance. A cluster of overexpressed genes related to DOX resistance was observed. Included in this cluster was ABCB1 the P-glycoprotein transporter protein gene and MMP1 (Matrix Metalloproteinase 1), indicative of the invasive nature of resistant cells, and the oxytocin receptor (OXTR), a potential new therapeutic target. Overexpression of genes associated with xenobiotic transformation, cell transformation, cell signalling and lymphocyte activation was also associated with DOX resistance as was estrogen receptor negativity. In all carcinoma cells, compared with HBL100 a putatively normal breast epithelial cell line, a cluster of overexpressed genes was identified which included several keratins, in particular keratins 8 and 18 which are regulated through the ras signalling pathway. Analysis of genomic amplifications and deletions revealed specific genetic alterations common to both intrinsic and acquired DOX resistance including ABCB1, PGY3 (ABCB4) and BAK. The findings shown here indicate new possibilities for the diagnosis of DOX resistance using gene expression, and potential novel therapeutic targets for pharmacological intervention.

Assessment of health status at two years of very low birthweight infants--clinical governance

Aims to establish a mechanism to determine prospectively the health status at two years of babies who weighed less than 1.5 kg at birth, born and receiving neonatal intensive care in North Wales. Maternal and neonatal data on all babies discharged from each of the three units in North Wales meeting this criteria were collated by the study coordinator. A mechanism for review of the health status at two years, corrected for gestational age, was established using the data set recommended by a working group convened by the National Perinatal Epidemiology Unit and Oxford Regional Health Authority. The procedures developed and the outcome data, for a two year cohort of babies born in 1995 and 1996, are reported. Concludes that prevalence of severe disability was similar to that found in other studies, with a considerable number exhibiting impaired growth and delay in speech development.

A randomized, controlled trial of remacemide for motor fluctuations in Parkinson's disease

BACKGROUND

Preclinical studies suggest that glutamate antagonists help ameliorate motor fluctuations in patients with PD treated with levodopa.

METHODS

In a multicenter, randomized, double-blind, placebo-controlled, parallel-group, dose-ranging study, the authors assessed the safety, tolerability, and efficacy of the glutamate receptor blocker remacemide hydrochloride in 279 patients with motor fluctuations treated with levodopa. The primary objective was to assess the short-term tolerability and safety of four dosage levels of remacemide during 7 weeks of treatment. Patients were also monitored with home diaries and the Unified PD Rating Scale (UPDRS) to collect preliminary data on treatment efficacy.

RESULTS

Remacemide was well tolerated up to a dosage of 300 mg/d on a twice daily schedule and 600 mg/d on a four times daily schedule. The most common dosage-related adverse events were dizziness and nausea, as observed in previous studies of remacemide. The percent "on" time and motor UPDRS scores showed trends toward improvement in the patients treated with 150 and 300 mg/d remacemide compared with placebo-treated patients, although these improvements were not significant.

CONCLUSION

Remacemide is a safe and tolerable adjunct to dopaminergic therapy for patients with PD and motor fluctuations. Although this study had limited power to detect therapeutic effects, the observed improvement is consistent with studies of non-human primates with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced parkinsonian signs and symptoms. Additional studies are warranted to confirm these results over an extended period of observation, and to explore the potential neuroprotective effects of remacemide in slowing the progression of PD.