Pharmacokinetics, Metabolism, and Excretion of Intravenous [14C]Difelikefalin in Healthy Subjects and Subjects on Hemodialysis

BACKGROUND AND OBJECTIVE

Difelikefalin, a selective kappa-opioid receptor agonist, is the first approved treatment for moderate-to-severe pruritus in patients with end-stage renal disease (ESRD) on hemodialysis (HD) in the USA and Europe. The purpose of this open-label study was to investigate the pharmacokinetics and disposition of [14C]difelikefalin following a single intravenous dose in subjects with normal renal function and subjects on HD.

METHODS

Twelve adult males (n = 6 healthy subjects; n = 6 subjects on HD) received single intravenous doses of [14C]difelikefalin containing 100 µCi (total doses of 1.7-3.0 μg/kg difelikefalin). Blood, urine, feces, and dialysate samples (when applicable) were collected after dosing.

RESULTS

The median time to maximum concentration was similar for HD and healthy subjects, occurring at 5 min post-dose. The mean area under the concentration-time curve (AUC) was approximately 11-fold higher in HD versus healthy subjects; mean plasma half-life was 38.0 h and 2.6 h, respectively. In healthy subjects, 80.5% of the dose was recovered in urine, and 11.3% was recovered in feces. In subjects on HD, 58.8% of the dose was recovered in feces, and 19.5% was recovered in dialysate [for subjects on HD with residual kidney function (n = 3), 11.2% was recovered in urine]. Based on plasma AUClast, parent [14C]difelikefalin was the most abundant analyte in systemic circulation (> 99% of total exposure) for both cohorts. Metabolite profiles in urine and feces suggested minimal metabolism of the parent compound.

CONCLUSION

In subjects on HD, difelikefalin total exposure was higher and plasma half-life was longer compared with subjects with intact renal function. Metabolism was low in both healthy subjects and subjects on HD, with unchanged drug representing > 99% of systemic circulation; however, the route of excretion was primarily into urine versus feces in healthy subjects, and feces versus dialysate in subjects on HD.

REGISTRATION

ClinicalTrials.gov NCT03947970.

Efficacy of Difelikefalin for the Treatment of Moderate to Severe Pruritus in Hemodialysis Patients: Pooled Analysis of KALM-1 and KALM-2 Phase 3 Studies

Rationale & Objective

Chronic kidney disease–associated pruritus (CKD-aP) in patients treated by hemodialysis (HD) impairs quality of life (QoL). Difelikefalin, a selective κ-opioid receptor agonist, decreased the intensity of CKD-aP in patients undergoing HD. This pooled analysis evaluated difelikefalin’s efficacy and the itch-related QoL overall and in subgroups defined by demographics or disease characteristics.

Study Design

In KALM-1 and KALM-2, participants were randomized (1:1) to receive intravenous difelikefalin or placebo 3 times/wk for 12 weeks, followed by a 52-week open-label extension.

Setting & Participants

Adults with moderate to severe CKD-aP treated by HD in North America, Europe, and the Asia-Pacific region.

Intervention

Intravenous difelikefalin at 0.5 mcg/kg or placebo.

Outcomes

Itch intensity (Worst Itching Intensity Numerical Rating Scale [WI-NRS]) and itch-related QoL (Skindex-10 and 5-D Itch questionnaires).

Results

851 participants were randomized (difelikefalin, n = 426; placebo, n = 425). This pooled analysis demonstrated early     (week 1), sustained difelikefalin efficacy, with significantly greater achievement of ≥3-point WI-NRS reduction with difelikefalin (51.1%) versus placebo (35.2%; P < 0.001). Achievement of a ≥4-point WI-NRS reduction was significantly greater with difelikefalin (38.7%) versus placebo (23.4%; P < 0.001). Difelikefalin reduced itch intensity in subgroups based on age, sex, anti-itch medication use, the presence of specific medical conditions, and gabapentin or pregabalin use. More participants receiving difelikefalin versus placebo achieved clinically meaningful decreases of ≥15 points on the Skindex-10 scale (55.5% vs 40.5%, respectively; P < 0.001) and ≥5 points on the 5-D Itch scale (52.1% vs 42.3%, respectively; P = 0.01), with sustained 5-D Itch effects up to 64 weeks.

Limitations

Subgroup samples were small. The WI-NRS, Skindex-10, and 5-D Itch are not used in routine clinical care of dialysis patients; therefore, findings may not reflect the real-world effectiveness of difelikefalin.

Conclusions

Difelikefalin demonstrated rapid, sustained efficacy, with consistent results in diverse populations of patients treated by HD.

Funding

Cara Therapeutics, Inc.

Trial Registration

The KALM-1 trial is registered as NCT03422653 and the KALM-2 trial is registered as NCT03636269.

FC 022AN OPEN-LABEL, MULTICENTER STUDY TO EVALUATE THE SAFETY AND EFFECTIVENESS OF INTRAVENOUS DIFELIKEFALIN IN PATIENTS WITH MODERATE-TO-SEVERE CKD–ASSOCIATED PRURITUS UNDERGOING HEMODIALYSIS

Background and Aims

Chronic kidney disease–associated pruritus (CKD-aP) is a common and highly distressing condition in patients undergoing hemodialysis (HD). CKD-aP is associated with sleep disturbances, significant quality-of-life (QoL) impairment, and increased morbidity and mortality. Difelikefalin (DFK) is a selective kappa opioid receptor agonist in development for CKD-aP that has minimal central nervous system penetration. In placebo-controlled phase 3 trials of patients with moderate to severe CKD-aP undergoing HD, intravenous (IV) DFK had an acceptable safety profile and demonstrated significant reductions vs placebo in itch intensity. We report safety and effectiveness outcomes, including itch-related QoL and sleep measures, from a phase 3 open-label study of DFK in patients with moderate to severe CKD-aP.

Method

This multicenter, open-label study conducted in the United States and Europe enrolled patients with moderate to severe CKD-aP (mean baseline 24-hour Worst Itching Intensity Numerical Rating Scale [WI-NRS] score ≥5) undergoing HD for ≥3 months. Patients received IV DFK 0.5 mcg/kg 3 times/week at the end of each HD session for up to 12 weeks. Predefined effectiveness endpoints at week 12 included ≥3-point and ≥4-point improvement in the weekly mean of the 24-hour WI-NRS score (range from 0 [no itching] to 10 [worst itching imaginable]). Change from baseline in QoL at week 12 was assessed using the 5-D itch and Skindex-10, multidimensional itch-related questionnaires validated in CKD-aP (higher scores indicate worse QoL). The proportion of patients with no problems (score of 1) on the skin irritation and self-confidence domains of the EQ-PSO questionnaire was evaluated. Post hoc endpoints included complete resolution in WI-NRS (≥75% of week 12 scores 0 or 1) and Sleep Quality Questionnaire total score assessments (range of possible scores, 0 [did not interfere] to 10 [completely interfered]), including ≥3-point and ≥4-point improvement in weekly mean score and complete resolution (all scores of 0) at week 12. Safety assessments and adverse events (AEs) were evaluated. Data were summarized descriptively.

Results

Among 222 patients who received DFK, 197 (88.7%) completed the study. At baseline, mean ±SD age was 58.1 ±12.8 years and 54.5% of patients were male. Baseline mean ±SD WI-NRS score was 7.6 ±1.3, Sleep Quality score was 6.6 ±2.2, 5-D itch score was 17.1 ±3.5, and Skindex-10 score was 32.9 ±14.3. At week 12, the majority of patients achieved ≥3-point and ≥4-point improvement in WI-NRS (73.7% and 59.3%) and Sleep Quality score (66.0% and 56.7%). Complete resolution of WI-NRS and Sleep Quality score was observed in 29.4% and 19.1% of patients, respectively (Figure). DFK was associated with improvements in mean 5-D itch (−7.1 ±4.3) and Skindex-10 (−21.0 ±15.6) scores at week 12. The proportion of patients reporting no problems in the skin irritation EQ-PSO domain increased from 1.4% at baseline to 28.9% at week 12, and self-confidence EQ-PSO domain scores increased from 63.5% at baseline to 73.2% at week 12. Overall, 64.4% (143/222) of patients reported ≥1 treatment-emergent AE (TEAE). The most commonly reported TEAEs (≥4% of patients) were diarrhea (5.0% [11/222]), nausea (4.5% [10/222]), and hyperkalemia (4.1% [9/222]). Serious TEAEs were reported by 20.3% (45/222) of patients; no serious TEAEs were related to study drug.

Conclusion

In this phase 3 open-label study in patients with moderate to severe CKD-aP undergoing HD, DFK was generally well tolerated with an acceptable safety profile. DFK demonstrated effectiveness based on reduction of itch intensity, and improvements in sleep quality and itch-related QoL at week 12. The majority of patients reported ≥3-point or ≥4-point improvement in WI-NRS and Sleep Quality scores, with some reporting complete resolution. Findings from this open-label study provide insight into the potential real-world effectiveness of DFK in moderate to severe CKD-aP.

Randomized Controlled Trial of Difelikefalin for Chronic Pruritus in Hemodialysis Patients

Introduction

There is an unmet medical need for pruritus associated with chronic kidney disease, a distressing complication characterized by generalized and persistent itch affecting 20% to 40% of patients undergoing hemodialysis. Here we report the results of a phase 2 trial evaluating the efficacy and safety of a novel peripherally restricted kappa opioid receptor agonist, difelikefalin, in adult patients undergoing hemodialysis with pruritus.

Methods

In this study, 174 hemodialysis patients with moderate-to-severe pruritus were randomly assigned to receive difelikefalin (0.5, 1.0, or 1.5 μg/kg) or placebo intravenously thrice weekly after each hemodialysis session for 8 weeks in a double-blind, controlled trial. The primary endpoint was the change from baseline at week 8 in the weekly mean of the 24-hour Worst Itching Intensity Numerical Rating Scale score. The secondary efficacy endpoint was the change in itch-related quality of life measured by the Skindex-10 questionnaire. Other endpoints included safety, sleep quality, and additional measures including the 5-D itch scale.

Results

A significant reduction from baseline in itch intensity scores at week 8 favored all difelikefalin doses combined versus placebo (P = 0.002). Difelikefalin also showed improvement over placebo in Skindex-10, 5-D itch, and sleep disturbance scores (P ≤ 0.005). Overall, 78% of patients receiving difelikefalin reported treatment-emergent adverse events versus 42% of patients given placebo, with diarrhea, dizziness, nausea, somnolence, and fall being the most frequent (≥5%).

Conclusion

In this trial, difelikefalin effectively reduced itching intensity and improved sleep and itch-related quality of life.

The British Association for Sexual Health and HIV 2016 UK national audit and survey of clinic policies in relation to risk assessment, HIV testing and follow-up

This national audit of 142 clinics demonstrated that the majority of clinics surveyed had policies and agreed clinical practice for alcohol and recreational drug enquiry, as well as documentation of HIV test refusal, although this was not the case in 24% of clinics as regards alcohol usage, 21% of clinics as regards recreational drugs use and 43% of clinics as regards chemsex usage. Regarding management of HIV test refusal, there was no policy or agreed practice in 13% of clinics with respect to men having sex with men (MSM) attenders, and in 18% of clinics for heterosexual attenders. Seventy percent of clinics had HIV point of care tests (POCT) available. Recommendations include: all clinics should have a policy of routine enquiry about alcohol, recreational drugs and chemsex, all clinics should record reasons for HIV test refusal and all clinics should provide testing alternatives to improve uptake, e.g. point of care testing or home sampling.

Vulval Crohn's disease – a multi-specialty approach

We report a case of Crohn's disease where the patient initially presented with vulval ulceration to the gynaecology unit. Initial investigations were planned jointly by both the gynaecology and genitourinary medicine staff. An examination under general anaesthetic by both teams was performed and biopsies taken. These showed a chronic inflammatory process with epithelioid granulomas. The teams then referred the case to the dermatology team who made the diagnosis of vulval Crohn's disease and initiated treatment with prednisolone and azathioprine. The case illustrates the need for a multi-speciality approach when dealing with such cases.

Early invasive squamous cell carcinoma of the penis presenting in a 39-year-old man

Penile cancer, albeit an uncommon malignancy, commonly affects men aged between 50 and 70 years, often with a history of predisposing factors such as Bowen's disease or leukoplakia. We describe a case of early invasive squamous cell carcinoma of the penis in a 39-year-old man with no history of predisposing factors, treated by a partial glansectomy.

UK National Audit of Sexual History-taking: Case-notes audit

A national audit of sexual history-taking was conducted in genitourinary medicine clinics in the UK in 2008. Data were aggregated by region and clinic, allowing practice to be compared between regions, as well as to national averages and against national Guidelines. In this paper the case-notes of 4121 patients were audited. A high proportion of the case-notes were deemed to be completely legible. In other respects there is considerable inter-regional variation in the adherence to national Guidelines. Interventions are especially required to improve documentation of practice in discussing condom use, HIV risk assessment, offer of a chaperone and assessment for hepatitis B vaccination and hepatitis C testing, and issues concerning sexual contacts.

UK National Audit of Sexual History-taking: clinic policies audit

Provision of a confidential, private environment for sexual history-taking was provided in almost all clinics. However, less than half of the clinics had a policy displayed about their confidentiality policy in waiting areas, although more had this available by other means. About two-thirds of clinic information/advertising literature included information about the need to take a sexual history. Sixty percent of clinics assessed clinician communication skills as part of service quality. Most clinics had policies relating to patients whose first language is not English, but only around half of clinics had policies for hearing difficulties and learning difficulties. Policies are also lacking in some clinics for documentation of the offer of chaperones and assessment of the competency of under-16-year-olds to consent to history-taking and examination.

Audit on the success of partner notification for sexually transmitted infections in the West Midlands

The aim of this study is to investigate the success of partner notification (PN) among 13 genitourinary medicine centres in West Midlands. The West Midlands Audit Group conducted a regional audit between June and August 2007. Information on screening and management of patients with chlamydia, gonorrhoea, early syphilis and HIV were collected separately. Participating centres were asked to provide PN details for 10 index patients with each of chlamydia, gonorrhoea, early syphilis and HIV infections. For each index patient with chlamydia or gonorrhoea, 0.54 and 0.44 partners were screened, respectively. Among partners of patients with syphilis and HIV, 24% and 35% were screened, respectively. Only 9% of 311 screened partners were involved in casual partnerships with index patients. Acquisition of more robust targets for PN, better documentation, improved communication between genitourinary (GU) medicine centres, and provider referral may improve the performance of PN for Sexually transmitted infections.

Trends in sexually transmitted infections (other than HIV) in older people: analysis of data from an enhanced surveillance system

OBJECTIVE

This study examines the distribution of selected sexually transmitted infections (STIs) in older people (aged >/=45 years) attending genitourinary medicine (GUM) clinics in the West Midlands, UK.

METHODS

Analysis of data from the regional enhanced STI surveillance system for the period 1996-2003. Selected STIs were chlamydia, genital herpes, genital warts, gonorrhoea and syphilis.

RESULTS

Altogether, 4445 STI episodes were reported among older people during the study period. Between 1996 and 2003 older people accounted for 3.7% and 4.3%, respectively, of all GUM clinic attendances. The rate of STIs in older people more than doubled in 2003 compared with 1996 (p<0.0001). Rates for all five selected diagnoses were significantly higher in 2003 compared to 1996. A significantly increasing trend over time was seen overall (p<0.0001) and for each of the selected diagnoses. Overall, males and those aged 55-59 years of age were significantly more likely to be affected.

CONCLUSIONS

This study provides evidence of significant increases in attendance at GUM clinics by older people. Although it is recognised that young people should remain the focus of sexual health programmes, the results indicate that sexual risk-taking behaviour is not confined to young people but also occurs among older people. There is therefore a need to develop and implement evidence-based multifaceted sexual health programmes that while aiming to reduce STI transmission among all age groups should include interventions aimed specifically at older people and address societal and healthcare attitudes, myths and assumptions about sexual activity among older people.

An audit on the management of pelvic inflammatory disease in the West Midlands, UK

The potential complications of pelvic inflammatory disease (PID) make optimizing its management a high priority. A clinical audit of PID against current national management guidelines was conducted in 14 departments of genitourinary medicine in the West Midlands for women presenting with PID between January and December 2005. There were a total of 810 diagnoses of PID made from a total of 49,390 female attendees for that year, giving an incidence of 164 cases per 10,000 attendees. Of these 810 cases, data collection and analysis for this audit were performed on 139. An ofloxacin 400 mg twice daily (b.i.d.) based regimen was prescribed in 91 (65%, 95% confidence interval [CI] 57-73%) cases. Doxycycline 100 mg b. i. d. for 14 days plus metronidazole 400 mg b. i. d. for 5-14 days was prescribed in 44 (32%, 95% CI 25-40%) cases, but a third-generation cephalosporin was only given with this regimen in three cases. Partner notification was performed in 101 (73%, 95% CI 65-79%) cases. A total of 130 male contacts were recorded on the data collection forms, and of these 58 (45%) were traced and 51 (39%), treated. A follow-up appointment was given to 133 (96%, 95% CI 91-98%) women, although in most cases this was for seven days or more, and 104 (78%, 95% CI 67-81%) women attended for follow-up. Adherence to the national guidelines in this cohort of patients did not reach the national standard for choice of treatment regimen nor did it attain the target for proportion of male partners traced. Barriers preventing adherence to the national guidelines need to be explored and appropriate assistance given to physicians to help meet national standards of care.

Extended epoetin alfa dosing as maintenance treatment for the anemia of chronic kidney disease: the PROMPT study

AIM

To determine whether extended epoetin alfa dosing schedules of up to once every four weeks are as effective as weekly dosing in maintaining hemoglobin (Hb) levels in patients with anemia of chronic kidney disease (CKD).

METHODS

This randomized, open-label trial enrolled patients with anemia of CKD not on dialysis. Patients were required to have a stable Hb level (> or = 11.0 g/dl) and to have been previously receiving epoetin alfa for two or more months. Patients were randomized to one of four subcutaneously administered epoetin alfa dosing regimens: 10,000 units (U) once weekly (QW), 20,000 U every two weeks (Q2W), 30,000 U every three weeks (Q3W) or 40,000 U every four weeks (Q4W). Dose reductions, but not escalations, were permitted. Patients received treatment for a total of 16 weeks. The primary endpoint for the trial was the mean final Hb measurements of the QW, Q2W, Q3W, and Q4W groups. The primary efficacy analyses were non-inferiority assessments of the mean final Hb measurements of the Q2W, Q3W, and Q4W groups, compared with the QW group. The primary efficacy analyses were performed using a modified intent-to-treat (MITT) population, defined as all patients meeting all inclusion/exclusion criteria (or, if not satisfying all criteria, were granted an exemption at study entry), and who were randomized and received at least one dose of study medication. A per-protocol population, based on all patients who met the MITT criteria and completed the entire study, was used to evaluate the robustness of the MITT results. Quality of life was assessed for all dosing groups throughout the study. Safety was based on all patients randomized who received at least one dose of study medication.

RESULTS

A total of 519 patients were enrolled; 445 were included in the MITT population. The four treatment groups were comparable with respect to baseline characteristics. The primary etiologies of CKD were diabetes (45.7%) and hypertension (29.9%). The mean baseline Hb, serum creatinine and glomerular filtration rate for all patients were 11.9 +/- 0.8 g/dl, 3.1 mg/dl, and 21.1 ml/min/1.73 m2, respectively. The mean baseline transferrin saturation was 25.2% and the mean ferritin was 201.9 ng/ml for all patients. All groups had a mean final Hb of > 11.0 g/dl. The mean final Hb levels of the Q2W and Q4W groups were statistically non-inferior to the QW group. The results of the per-protocol analysis were consistent with the MITT results. In addition, 93.5%, 89.5%, 77.2%, and 76.0% of patients maintained a mean Hb > or = 11.0 g/dl throughout the course of the study in the QW, Q2W, Q3W, and Q4W groups, respectively. Quality of life was maintained or improved from baseline to final within each dosing group. There were no significant differences in the mean final quality of life scores between the QW group and the Q2W, Q3W, and Q4W groups. Among the 513 patients evaluated for safety, epoetin alfa was well tolerated with no differences in adverse events between groups. The incidence of thrombotic adverse events was low (2.5% of patients), as was mortality (1.4% of patients).

CONCLUSIONS

Approximately 90% of patients dosed once every two weeks and over 75% of patients dosed once every three or four weeks maintained mean Hb levels > or = 11.0 g/dl, consistent with the Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines. This study suggests that extended epoetin alfa dosing schedules are effective and safe for maintaining Hb, and may offer the possibility of increased flexibility and convenience for the majority of patients with the anemia of CKD.

Extended epoetin alfa dosing in chronic kidney disease patients: a retrospective review

BACKGROUND

The effectiveness of extended dosing of epoetin alfa beyond once-weekly (QW) has not been well explored in patients being treated for anaemia of chronic kidney disease (CKD). The current study was undertaken to assess the effectiveness of extended dosing in maintaining haemoglobin (Hb) levels in this population.

METHODS

A retrospective chart review was conducted to assess the efficacy of extended epoetin alfa dosing in patients being treated for CKD-related anaemia. Eligible patients were to have received epoetin alfa once every 2 weeks (Q2W), 3 weeks (Q3W), 4 weeks (Q4W), or >Q4W administered subcutaneously for at least 3 months to maintain Hb > or = 11.0 g/dl. Patients were > or =18 years with serum creatinine 1.5 to 6.0 mg/dl for females and 2.0 to 6.0 mg/dl for males, and were not receiving renal replacement therapy. Epoetin alfa dose and dosing frequency were adjusted during treatment at the clinician's discretion. For analysis, patients were stratified into dosing groups based on their most dominant dosing regimen.

RESULTS

243 patients (mean age, 71.5 years; 79% white, 54% female) who received extended epoetin alfa dosing for a mean of 10.3 months were eligible for analysis. Mean baseline estimated glomerular filtration rate and mean serum creatinine were 21.2 ml/min/1.73 m(2) and 3.1 mg/dl, respectively. Primary causes of CKD included hypertension (36%) and diabetes (28%). Most patients (82%) receiving an extended epoetin alfa regimen maintained Hb > or =11.0 g/dl. The most common dosing regimen was Q2W (51%). Mean Hb for each dosing group was maintained between 11.6 g/dl and 12.4 g/dl during the study, and glomerular filtration rate remained stable. Epoetin alfa was well tolerated across all groups.

CONCLUSIONS

Data from private community nephrology practices showed that extended epoetin alfa dosing effectively maintained Hb > or =11.0 g/dl in 82% of these selected patients being treated for anaemia of CKD.

Surveillance of sexually transmitted infections in the West Midlands using anonymised individual patient datasets from genitourinary medicine clinics

Sexually transmitted infections (STIs) declined in the UK during the 1980s and early 1990s but have increased substantially since 1995. Within the overall increase there are important differences in the epidemiology of these infections. The current, aggregate system of STI data collection in the UK provides limited demographic information and is unable to fully explain these differences. More useful information can be obtained using an enhanced surveillance system that collects disaggregate, anonymised, individual patient data including ethnic group and truncated postcode of residence. Such a system has been set up in the West Midlands NHS region. The methodology of the project is described here along with the findings to date. These findings confirm that the burden of STIs disproportionately affects young persons, men who have sex with men, black ethnic minority groups and those living in urban areas. Identifying the groups at greatest risk in this way enables interventions to be more usefully targeted.

Gradient surface porosity in titanium dental implants: relation between processing parameters and microstructure

To be successful, an implant should be biocompatible, strong and contain surface pores to promote osseointegration. A one-step microwave sintering procedure of titanium powders was attempted in this work. The idea was to take advantage of the peculiar way microwave couple with metallic powders, i.e. generating heat in the interior of the sample and dissipating it away through the surface. This non-conventional heating of titanium powder produced a dense core with surface porosity. The dense core provides the strength while the surface pores promote bone growth. The experiments were carried out in a semi-industrial grade microwave cavity using a alpha-SiC susceptor. Power levels of 1-1.5 kW, and soaking periods of approximately 30 min were used. Microstructural characterization was carried out by a scanning electron microscope. The sintered titanium had gradient porosity on the surface with a thickness of about 100-200 microm depending on the microwave power. The pores were interconnected with size ranging from 30 to 100 microm. This kind of microstructure is favorable for cell growth. Tensile strength values as high as 400 MPa were obtained for these samples.

Spin-spin cross relaxation in single-molecule magnets

The one-body tunnel picture of single-molecule magnets (SMMs) is not always sufficient to explain the measured tunnel transitions. An improvement to the picture is proposed by including also two-body tunnel transitions such as spin-spin cross relaxation (SSCR) which are mediated by dipolar and weak superexchange interactions between molecules. A Mn4 SMM is used as a model system. At certain external fields, SSCRs lead to additional quantum resonances which show up in hysteresis loop measurements as well-defined steps. A simple model is used to explain quantitatively all observed transitions.

Comparison of multiplex PCR, PCR-ELISA and fluorogenic 5' nuclease PCR assays for detection of plasmid-bearing virulent Yersinia enterocolitica in swine feces

Swine are implicated as the principal animal reservoir for plasmid-bearing Yersinia enterocolitica (YEP(+)) strains that are pathogenic to humans. To evaluate the utility of the PCR for detection of YEP(+) strains in naturally-contaminated pig feces, samples were first enriched in Irgasan ticarcillin potassium chlorate broth for 48 h at 25 degrees C and then tested by multiplex PCR, PCR-ELISA, and fluorogenic 5' nuclease PCR assays. Three different primer sets for amplification of the ail gene sequences were used in these three assays. Three out of 50 (6%) samples were positive for YEP(+) strains using the multiplex PCR targeting the chromosomal ail (170 bp) and plasmid virF (591 bp) genes. Two of the 3 samples positive by the multiplex PCR were also positive by the PCR-ELISA method using primers targeting the ail gene (425 bp). In contrast, the fluorogenic 5' nuclease PCR assay failed to detect an ail gene sequence (118 bp) in any of the 50 samples. These results indicate that the multiplex PCR was the most reliable and sensitive assay for detecting YEP(+) strains in feces among the three assays evaluated.

Sample preparation methods for PCR detection of Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes on beef chuck shoulder using a single enrichment medium

To improve the utility of the polymerase chain reaction (PCR) for food samples, methods for preparing template DNA were developed to remove PCR inhibitors. Beef chuck shoulder medallions, artificially contaminated, individually or in combination, with Escherichia coli serotype O157:H7 strain FSIS 45753-35, Salmonella typhimurium DT104 strain 13HP, or Listeria monocytogenes strain Scott A at concentrations of 10, 1 and 0.5 cfu/cm(2)were swabbed with a sponge, and the sponges were enriched for 18 h at 37 degrees C in universal pre-enrichment broth (UPB). Enriched broth cultures (EBC), cell pellets (CP), or phosphate-buffered saline-washed cell pellets (PBSCP) from enriched sponge samples were compared for detection of E. coli O157:H7, S. typhimurium DT104, or L. monocytogenes by the PCR using the BAX(TM)system. Recovery of the three organisms was effective for detection of each pathogen at initial levels of 10, 1 and 0.5 cfu/cm(2)when inoculated separately, or in combination, onto the beef samples. Use of EBC, CP, or PBSCP of sponge-swabbed samples eliminated problems associated with inhibition of the PCR by food components, time-consuming extraction of DNA, and inhibition due to large amounts of non-target DNA derived from the food. The procedure involving enrichment of sponge-swabbed beef samples in UPB followed by PCR amplification using EBC with the BAX system is the most efficient and simple method for detection of E. coli O157:H7, S. typhimurium DT104, and L. monocytogenes.

Pyogenic granuloma of the penis--don't squeeze them

We report the case of a pyogenic granuloma on the shaft of the penis presenting with active bleeding secondary to attempted expression. Previously reported cases have documented such lesions on the prepuce and glans.

A review of ultrasound-guided percutaneous biopsy of the gastrointestinal tract in HIV-infected patients

OBJECTIVE

To illustrate the use of percutaneous ultrasound-guided biopsy of the gastrointestinal tract in HIV-infected patients to obtain a tissue diagnosis.

DESIGN

The technique was used in relation to relevant clinical situations in which a diagnosis may have only been reached by open biopsy.

METHOD

Three HIV-infected patients with suspected gastrointestinal tract lesions underwent percutaneous ultrasound-guided biopsy under local anaesthetic.

RESULTS

A tissue diagnosis was made in each case resulting in initiation or continuation of appropriate therapy and avoided the need for open biopsy under general anaesthetic.

CONCLUSION

Although the number of patients undergoing the procedure in this series was small, the technique has so far been shown to be safe and effective with few complications.

Haematospermia associated with malignant hypertension

Haematospermia is generally regarded as a benign, self limiting condition. Although no obvious cause is found in most cases, an uncommon but important predisposing factor is severe uncontrolled hypertension. We describe a case illustrating the need to routinely measure blood pressure in such instances.

Clinical aspects of sensitization

1. The incidence of broad sensitization has decreased significantly over the past 8 years, probably due to a decrease in pretransplant blood transfusions. Graft survival rates among broadly sensitized patients have improved over this time period (76% graft survival at 2 years posttransplant for patients transplanted in 1995-1996 compared with 66% for patients transplanted in 1989-1990). This is probably due to an improvement in immunosuppression and a related decrease in the incidence of acute rejection episodes. 2. As has been shown before, blood transfusions, previous pregnancies and failed allografts independently increased the incidence of sensitization. It is clear that certain subgroups of patients are more likely to become sensitized, given antigenic stimulation, as evidenced, for example, by the fact that 52% of patients receiving more than 10 units of blood prior to transplant were relatively unsensitized. Males seem to be less apt than nulliparous females to become broadly sensitized, although this may be due to the lower age of nulliparous females. Asians are the least likely race to become broadly sensitized. Among multiparous Asians who received more than 5 units of blood, 27% were broadly sensitized compared with 35% of comparable Whites and African Americans. 3. The incidence of acute rejection episodes increased with increasing degrees of sensitization. About 46% of first cadaveric allograft recipients with PRA levels greater than 50% had at least one acute rejection episode within 6 months after transplantation compared with 38% of unsensitized individuals. In addition, sensitized individuals were more likely to have an episode of early acute rejection before discharge from the hospital. 4. Induction with antilymphocyte antibody preparation was more commonly used in broadly sensitized patients. However, this therapeutic modality did not reduce the incidence of rejection episodes measured at 6 months posttransplant. In addition, the use of induction therapy for broadly sensitized patients has decreased with the advent of newer immunosuppressive protocols that include Neoral, MMF and FK506. 5. There was an association between the incidence of broad sensitization and delayed graft function. Induction therapy was more commonly used in patients with both delayed graft function and broad sensitization, although the decision to use this therapeutic modality seems to be made based on the presence of broad sensitization rather than the presence of delayed graft function. 6. Choosing the optimal immunosuppressive drug regimen is an important decision in broadly sensitized individuals because of the increase in acute rejections and decrease in overall graft survival in this group. Classic teaching suggests that this group of patients should be administered induction therapy with antilymphocyte antibody preparations. Early data suggests, however, that the combination of Neoral, mycophenolate and prednisone may be the optimal regimen for these individuals with respect to graft survival and that the addition of antibody induction therapy to any of the other commonly used regimens does not improve graft survival (at least up to 3 years after transplantation).

Maximizing plasmid stability and production of released proteins in Yersinia enterocolitica

Virulent serotypes of Yersinia enterocolitica carry a plasmid (pYV) encoding a family of proteins that are released into the medium and whose expression is temperature and calcium regulated. The plasmid is easily lost from cells during their growth in the laboratory. We have used sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting with a monoclonal antibody (3.2C) that is specific for a 25-kDa released protein to show that 32 degrees C is the lowest temperature at which plasmid-encoded proteins are expressed in quantity. The highest calcium concentration allowing full expression of these proteins was 445 to 545 microM at 32 degrees C. Calcium concentrations of 745 microM and above at 37 degrees C completely prevented the loss of pYV during multiple subcultures, while at 32 degrees C, calcium concentrations of 245 microM and greater were sufficient to stabilize the plasmid. Growth of Y. enterocolitica at pH 5.5 was slower than at neutral pH values, but it also resulted in greatly increased stability of pYV. These studies showed that bacterial growth, retention of pYV, and expression of plasmid-encoded proteins may be maximized at 32 degrees C with 445 microM calcium and that pYV stability is enhanced by growth at low pH. These observations suggest new approaches for isolation of plasmid-bearing virulent strains of Y. enterocolitica from samples contaminated with this organism and also may improve our understanding of pYV retention in vivo.