"We're trained to trust our patients": a qualitative study on the general practitioners' trust in patients for colorectal cancer shared care.

BACKGROUND: In a therapeutic partnership, physicians rely on patients to describe their health conditions, join in shared decision-making, and engage with supported self-management activities. In shared care, the patient, primary care, and specialist services partner together using agreed processes and outputs for the patient to be placed at the centre of their care. However, few empirical studies have explored physicians' trust in patients and its implications for shared care models. AIM: To explore trust in patients amongst general practitioners (GPs), and the impacts of trust on GPs' willingness to engage in new models of care, such as colorectal cancer shared care. METHODS: GP participants were recruited through professional networks for semi-structured interviews. Transcripts were integrity checked, coded inductively, and themes developed iteratively. RESULTS: Twenty-five interviews were analysed. Some GPs view trust as a responsibility of the physician and have a high propensity for trusting patients. For other GPs, trust in patients is developed over successive consultations based on patient characteristics such as honesty, reliability, and proactivity in self-care. GPs were more willing to engage in colorectal cancer shared care with patients with whom they have a developed, trusting relationship. CONCLUSIONS: Trust plays a significant role in the patient's access to shared care. The implementation of shared care should consider the relational dynamics between the patient and health care providers.

In a therapeutic partnership, physicians rely on patients to describe their health conditions, join in shared decision-making and engage with supported self-management activities. In shared care, the patient, primary care, and specialist services partner together using agreed processes and outputs for the patient to be placed at the centre of their care. Trust is key to this partnership. However, few studies have explored the physicians' trust in patients and its implications for shared care models. This study aims to explore trust in patients amongst general practitioners (GPs), and the impacts of trust on GPs' willingness to engage in new models of care, such as colorectal cancer shared care. After analysing 25 interview transcripts with GPs, we found some GPs view trust as a responsibility of the physicians, while in others, trust in patients developed over successive consultations based on patient characteristics such as honesty, reliability, and proactivity in self-care. GPs were more willing to engage in colorectal cancer shared care with patients whom they have a developed, trusting relationship. Trust plays a significant role in the patient's access to shared care. The rollout of shared care should consider the relational dynamics between the patient and health care providers.

Examining the effectiveness of different dental recall strategies on maintenance of optimum oral health: the INTERVAL dental recalls randomised controlled trial.

Objective To compare the clinical effectiveness of different frequencies of dental recall over a four-year period.Design A multi-centre, parallel-group, randomised controlled trial with blinded clinical outcome assessment. Participants were randomised to receive a dental check-up at six-monthly, 24-monthly or risk-based recall intervals. A two-strata trial design was used, with participants randomised within the 24-month stratum if the recruiting dentist considered them clinically suitable. Participants ineligible for 24-month recall were randomised to a risk-based or six-month recall interval.Setting UK primary dental care.Participants Practices providing NHS care and adults who had received regular dental check-ups.Main outcome measures The percentage of sites with gingival bleeding on probing, oral health-related quality of life (OHRQoL), cost-effectiveness.Results In total, 2,372 participants were recruited from 51 dental practices. Of those, 648 were eligible for the 24-month recall stratum and 1,724 participants were ineligible. There was no evidence of a significant difference in the mean percentage of sites with gingival bleeding on probing between intervention arms in any comparison. For those eligible for 24-month recall stratum: the 24-month versus six-month group had an adjusted mean difference of -0.91%, 95% CI (-5.02%, 3.20%); the 24-month group versus risk-based group had an adjusted mean difference of 0.07%, 95% CI (-3.99%, 4.12%). For the overall sample, the risk-based versus six-month adjusted mean difference was 0.78%, 95% CI (-1.17%, 2.72%). There was no evidence of a difference in OHRQoL (0-56 scale, higher score for poorer OHRQoL) between intervention arms in any comparison. For the overall sample, the risk-based versus six-month effect size was -0.35, 95% CI (-1.02, 0.32). There was no evidence of a clinically meaningful difference between the groups in any comparison in either eligibility stratum for any of the secondary clinical or patient-reported outcomes.Conclusion Over a four-year period, we found no evidence of a difference in oral health for participants allocated to a six-month or a risk-based recall interval, nor between a 24-month, six-month or risk-based recall interval for participants eligible for a 24-month recall. However, patients greatly value and are willing to pay for frequent dental check-ups.

INTERVAL (investigation of NICE technologies for enabling risk-variable-adjusted-length) dental recalls trial: a multicentre randomised controlled trial investigating the best dental recall interval for optimum, cost-effective maintenance of oral health in dentate adults attending dental primary care.

BACKGROUND: Traditionally, patients at low risk and high risk of developing dental disease have been encouraged to attend dental recall appointments at regular intervals of six months between appointments. The lack of evidence for the effect that different recall intervals between dental check-ups have on patient outcomes, provider workload and healthcare costs is causing considerable uncertainty for the profession and patients, despite the publication of the NICE Guideline on dental recall. The need for primary research has been highlighted in the Health Technology Assessment Group's systematic review of routine dental check-ups, which found little evidence to support or refute the practice of encouraging 6-monthly dental check-ups in adults. The more recent Cochrane review on recall interval concluded there was insufficient evidence to draw any conclusions regarding the potential beneficial or harmful effects of altering the recall interval between dental check-ups. There is therefore an urgent need to assess the relative effectiveness and cost-benefit of different dental recall intervals in a robust, sufficiently powered randomised control trial (RCT) in primary dental care. METHODS: This is a four year multi-centre, parallel-group, randomised controlled trial with blinded outcome assessment based in dental primary care in the UK. Practitioners will recruit 2372 dentate adult patients. Patient participants will be randomised to one of three groups: fixed-period six month recall, risk-based recall, or fixed-period twenty-four month recall. Outcome data will be assessed through clinical examination, patient questionnaires and NHS databases. The primary outcomes measure gingival inflammation/bleeding on probing and oral health-related quality of life. DISCUSSION: INTERVAL will provide evidence for the most clinically-effective and cost-beneficial recall interval for maintaining optimum oral health in dentate adults attending general dental practice. TRIAL REGISTRATION: ISRCTN95933794 (Date assigned 20/08/2008).

Sero-conversion rate of Syphilis and HIV among pregnant women attending antenatal clinic in Tanzania: a need for re-screening at delivery.

BACKGROUND: Despite the available cost effective antenatal testing and treatment, syphilis and human immunodeficiency virus (HIV) are still among common infections affecting pregnant women especially in developing countries. In Tanzania, pregnant women are tested only once for syphilis and HIV during antenatal clinic (ANC) visits. Therefore, there are missed opportunities for syphilis and HIV screening among those who were not tested during ANC visits and those acquiring infections during the course of pregnancy. This study was designed to determine the syphilis and HIV seroprevalence at delivery and seroconversion rate among pregnant women delivering at Bugando Medical Centre (BMC). METHODS: A cross sectional, hospital-based study involving pregnant women attending Bugando Medical Centre (BMC) antenatal clinic was done from January to March 2012. Serum samples were collected and tested for HIV and syphilis using HIV and syphilis rapid tests. Demographic and clinical data were collected using a standardized data collection tool and analysed using STATA version 11. RESULTS: A total of 331 and 408 women were screened for syphilis and HIV during antenatal respectively. Of 331 women who screened negative for syphilis at ANC, nine (2.7%) were seropositive at delivery while of 391who tested negative for HIV during ANC eight (2%) were found to be positive at delivery. Six (1.8%) and 23 (9%) of women who did not screen for syphilis and HIV at ANC were seropositive for syphilis and HIV at delivery respectively. There was significant difference of seroprevalence for HIV, among women who tested negative at ANC and those who did not test at ANC (2% vs.9%, P,<0.001). The overall prevalence of syphilis and HIV at delivery was 15 (2.3%) and 48 (7.2%) respectively. Syphilis seropositivity at delivery was significantly associated with HIV co-infection (p < 0.001), male partner circumcision (p = 0.011) and alcohol use among women (p < 0.001). CONCLUSIONS: The current protocol of screening for syphilis and HIV only once during pregnancy as practiced in Tanzania may miss women who get re-infected and seroconvert during pregnancy. Re-screening for syphilis and HIV during the course of pregnancy and at delivery is recommended in Tanzania as it can help to identify such women and institute appropriate treatment.

A light microscopy study of the migration of Naegleria fowleri from the nasal submucosa to the central nervous system during the early stage of primary amebic meningoencephalitis in mice.

The migratory pathway of Naegleria fowleri from the nasal submucosa to the central nervous system (CNS) during the early stage of primary amebic meningoencephalitis (PAM) was investigated in mice. Twenty-one-day-old CD-1 mice were inoculated by intranasal instillation of 1 x 10(6) amebas. Animals were divided into 3 groups of 5 and, after being anesthetized, were killed at intervals of 24, 32, and 48 hr postinoculation by transcardial perfusion with formaldehyde, acetic acid, and methanol. The heads were decalcified, divided in the midsagittal plane, and the area of the cribriform plate removed and embedded in paraffin. Serial sections were cut at 8 microm and stained with a combination of celestin blue, Harris' hematoxylin, and acid fuchsin for light microscopy. Focal inflammation and amebas were observed in the submucosal nerve plexus, olfactory nerves penetrating the cribriform plate, and the olfactory bulb of the brain as early as 24 hr postinoculation. The time periods selected assured that the disease process would not obliterate soft tissue structures. Earlier studies used moribund mice in which the inflammation and the number of amebas were overwhelming. The present study provides convincing evidence that amebas gain initial access to the CNS through olfactory nerves within the cribriform plate during the early stages of PAM.

Amebicidal activity of wild animal serum.

The sera of 16 species of wild animals representing 5 classes of vertebrates were assayed for amebicidal activity against species of Naegleria. The greatest activity was observed for sera of bullfrogs, muskrats, and raccoons, all of which are animals associated with water. In contrast, the sera from animals such as toads, box turtles, sparrows, and squirrels exhibited minimal or no amebicidal activity. In general, pathogenic Naegleria tended to be less susceptible than nonpathogenic Naegleria to the lytic effect of raccoon serum. Heat-inactivated serum was not amebicidal, suggesting that perhaps complement may be involved in the serum-mediated lysis of amebas.

Viability of pathogenic Acanthamoeba and Naegleria and virulence of N. fowleri during long-term cryopreservation.

This is a followup report on the viability of pathogenic Acanthamoeba castellanii, Naegleria australiensis, and N. fowleri during 5 years of cryopreservation and the virulence of N. fowleri during 30 months of cryostorage, all at -70 degrees C. The greatest decrease in viability occurred during the first year of freezing and was 10-fold greater than the average yearly decrease during years 2-5. At 5 years of cryostorage viability was 33% for A. castellanii, 38% for N. fowleri and 51% for N. australiensis. Virulence of N. fowleri did not decrease during 30 months of freezing and what appeared to be an increase in virulence during cryopreservation may be the result of reduced viability of the less virulent amebae in a culture.

Techniques for isolating thermotolerant and pathogenic freeliving amebae.

Several conditions of isolation were evaluated to determine which yielded the greatest number of thermotolerant and pathogenic freeliving amebae. Swab samples, easier to obtain and process, produced more pathogenic amebae than water samples. If water samples are required, 50-ml volumes gave the greatest percentage of pathogenic isolates. An incubating temperature of 42 degrees C yielded the most thermotolerant amebae. A total of 11 pathogenic isolates were obtained from 762 environmental samples and were Acanthamoeba (55%), Naegleria fowleri Carter, 1970 (27%), and N. australiensis De Jonckheere, 1981 (18%).

Seasonal distribution of pathogenic free-living amebae in Oklahoma waters.

Pathogenic free-living amebae cause serious human disease, including infection of the eye and the central nervous system. The purpose of this study was to sample aquatic environments in the Tulsa, Oklahoma, area year-round for the presence of these disease-causing amebae. A total of 34 pathogenic isolates were obtained from 2,016 processed water and swab samples. Pathogenicity was determined by the ability of amebae to cause death in mice after intranasal inoculation. Pathogenic amebae were isolated during every month of the year and were identified as Naegleria australiensis (38%), Acanthamoeba species (35%), N. fowleri (18%), and leptomyxid amebae (9%). Pathogenic leptomyxids have not previously been reported from the environment. The greatest percentage of recovery of pathogens occurred during the spring and autumn. The prevalence of pathogenic free-living amebae in the sampled waters was 1 pathogen/3.4 l water.

Reduction in virulence of Naegleria fowleri following growth with cholesterol.

It has been reported that the virulence of axenically cultivated Entamoeba histolytica increases following growth with cholesterol. The purpose of this study was to determine whether cholesterol would enhance the virulence of axenically cultivated Naegleria fowleri. Amoebae were cultivated in axenic medium with (100 micrograms/ml) or without cholesterol for 6 months and tested in mice for changes in virulence. After 6 months of continuous cultivation. N. fowleri grown with cholesterol was less virulent for mice than the same strain grown without cholesterol.

Enhancement of virulence of Naegleria fowleri by growth in Vero-cell cultures.

The virulence of Naegleria fowleri for mice decreases with prolonged maintenance in axenic culture. Would the virulence be affected if amebas were grown in African green-monkey kidney (Vero)-cell cultures rather than in axenic culture? The weakly virulent LEE strain of N. fowleri was cultivated with Vero cells for 6 mo and tested in mice for changes in virulence. We found that continuous growth in Vero-cell cultures enhanced the virulence of the LEE strain and we propose that, as an alternative to serial passage in mice, the virulence of weakly virulent strains of N. fowleri may be enhanced by maintenance in Vero-cell cultures.

Cryopreservation of pathogenic free-living amebae.

A variety of conditions of cryopreservation were evaluated in order to define a single procedure for freezing the amebae of pathogenic Naegleria and Acanthamoeba. The average best conditions for freezing the three species studied were: 1 x 10(6) exponentially growing amebae/ml of freezing medium consisting of 12% dimethylsulfoxide, 20% heat-inactivated bovine calf serum, 4% glucose, in Mix ameba medium; 30 min equilibration at 23 degrees C (room temperature), followed by 60 min at -20 degrees C, with storage at -70 degrees C. Under these conditions viability after 1 month of freezing was 53% for Acanthamoeba castellanii, 64% for Naegleria fowleri, and 66% for Naegleria australiensis. After 12 months of freezing, viability was 39% for A. castellanii, 47% for N. fowleri, and 53% for N. australiensis.

Virulence of Naegleria fowleri affected by axenic cultivation and passage in mice.

The virulence of Naegleria fowleri decreases with prolonged axenic cultivation. The decline in virulence of highly virulent, mouse-passaged LEE strain amebae was monitored during 5 years of continuous axenic cultivation. The most rapid decrease in virulence occurred during the first 2 years. Virulence could be restored to original levels by 3 serial passages in mice. The composition of axenic media also affected the virulence of N. fowleri, with a more enriched medium appearing to restore some of the virulence of a weakly virulent strain.

Flagella number among Naegleria flagellates.

Scanning electron microscopy was used to determine the number of flagella on the flagellates of Naegleria australiensis, N. fowleri, N. gruberi, and N. jadini. Although the majority of flagellates had 2 flagella, there was considerable variation among individual cells. The number of flagella per flagellate varied from 1-8, with 2.4 being the average number per cell. For the different species, the average number of flagella per cell ranged from 2.0 in N. jadini to 3.1 for N. australiensis. The greatest amount of variation occurred in N. australiensis, with only 43% of the cells having 2 flagella. By contrast, 92% of N. fowleri cells had 2 flagella. Naegleria jadini and N. gruberi were intermediate with 80% and 74% biflagellates, respectively.

Susceptibility of wild mammals to infection with Naegleria fowleri.

Animals of 4 families of small wild mammals were live-trapped and inoculated intranasally with Naegleria fowleri to determine patterns of susceptibility. Of the 7 species of animals examined, only rodents were susceptible to N. fowleri. Susceptible animals were eastern gray squirrel, hispid cotton rat, muskrat, and house mouse. Mammals that were not susceptible at a dose of 10(6) were opossum, raccoon, and eastern cottontail rabbit. Perhaps rodents and humans share a common anatomical or physiological determinant that makes them susceptible to infection with N. fowleri.

Mammalian cell cultures affected by Naegleria gruberi.

Amebae of 8 strains of Naegleria gruberi were able to destroy 10 established mammalian cell lines including lung, kidney, ovary, connective tissue, neuroblastoma, and laryngeal and cervical carcinoma cells. The strains of N. gruberi varied in their ability to produce a destructive effect (DE) in African green monkey kidney (Vero) cell cultures. However, cell line susceptibility was found to be equivalent when tested with the considerably destructive 1518/l strain of N. gruberi. The Vero cell line proved to be a useful indicator culture for assessing the destructive potential of N. gruberi strains. Other factors affecting the extent of DE produced were ameba to mammalian cell ratio and the length of time that amebae were maintained in cell culture.

Cytopathogenicity of Naegleria fowleri in mammalian cell cultures.

A total of 13 strains of Naegleria fowleri were cytopathogenic for lung, kidney, foreskin, ovary, connective tissue, neuroblastoma, laryngeal carcinoma, and cervical carcinoma mammalian cell lines. The strains of N. fowleri varied considerably in their ability to produce a cytopathic effect (CPE). Likewise, the different mammalian cell lines exhibited varying degrees of susceptability to the cytopathogenicity of the amebae. The African green-monkey kidney (Vero) cell line proved to be useful for assessing the cytopathogenic potential of N. fowleri strains. Although one strain failed to produce CPE in Vero-cell cultures, it did so in the two neuroblastoma cell lines. Other factors affecting the extent of CPE produced were incubation temperature, ameba: mammalian cell ratio, and the length of time during which amebae were maintained in cell culture.

Intranasal immunization of mice against Naegleria fowleri.

The purpose of this research was to determine whether mice could be protected from lethal challenge with Naegleria fowleri by prior intranasal exposure to pathogenic and nonpathogenic Naegleria. Mortality ranged from 0 to 100% for mice inoculated intranasally (i.n.) with 5 x 10(3) amebae of 13 human isolates of N. fowleri. Mice were immunized and challenged i.n. using live amebae of strains of low, medium, and high virulence. The greatest protection against lethal challenge was afforded by three immunizing doses of 10(3) amebae per dose of the strain of medium virulence. Nonpathogenic N. gruberi also was used to immunize mice i.n. against lethal challenge with N. fowleri. Protection was greater following immunization with N. gruberi than it was after immunization with N. fowleri, suggesting that nonpathogenic N. gruberi may be a better immunogen in protecting mice against lethal naeglerial challenge.

Conditions for maximum enflagellation in Naegleria fowleri.

Ameba to flagellate transformation in Naegleria fowleri (Lovell strain) was affected by growth temperature, phase of growth, strain of ameba, culture agitation, enflagellation temperature, enflagellation diluent, and cell concentration. Amebae transformed best when they were grown without agitation and enflagellated with agitation. Regardless of growth temperature (23 degrees, 30 degrees, 37 degrees, and 42 degrees C were tested), amebae transformed best at 37 degrees C. Enflagellation was greatest for cells harvested between 24 h (mid-exponential) and 84 h (late stationary) of growth.