Urine steroid metabolomics as a diagnostic tool in primary aldosteronism

Primary aldosteronism (PA) causes 5-10% of hypertension cases, but only a minority of patients are currently diagnosed and treated because of a complex, stepwise, and partly invasive workup. We tested the performance of urine steroid metabolomics, the computational analysis of 24-hour urine steroid metabolome data by machine learning, for the identification and subtyping of PA. Mass spectrometry-based multi-steroid profiling was used to quantify the excretion of 34 steroid metabolites in 24-hour urine samples from 158 adults with PA (88 with unilateral PA [UPA] due to aldosterone-producing adenomas [APAs]; 70 with bilateral PA [BPA]) and 65 sex- and age-matched healthy controls. All APAs were resected and underwent targeted gene sequencing to detect somatic mutations associated with UPA. Patients with PA had increased urinary metabolite excretion of mineralocorticoids, glucocorticoids, and glucocorticoid precursors. Urine steroid metabolomics identified patients with PA with high accuracy, both when applied to all 34 or only the three most discriminative steroid metabolites (average areas under the receiver-operating characteristics curve [AUCs-ROC] 0.95-0.97). Whilst machine learning was suboptimal in differentiating UPA from BPA (average AUCs-ROC 0.65-0.73), it readily identified APA cases harbouring somatic KCNJ5 mutations (average AUCs-ROC 0.79-85). These patients showed a distinctly increased urine excretion of the hybrid steroid 18-hydroxycortisol and its metabolite 18-oxo-tetrahydrocortisol, the latter identified by machine learning as by far the most discriminative steroid. In conclusion, urine steroid metabolomics is a non-invasive candidate test for the accurate identification of PA cases and KCNJ5-mutated APAs.

The flavonoid fustin exerts anti-inflammatory effect in a model of carrageenan-induced paw oedema

Carrageenan-induced paw oedema is a widely used model of acute inflammation. The objective of this study was to assess the effect of the flavonoid fustin on carrageenan-induced acute paw inflammation in rats. Thirty male Wistar rats were distributed equally between three groups – control, F10, and F20. In the course of 1 week, animals were treated once daily by intragastric gavage as follows: control group – with distilled water (10 mL kg−1) containing 50 μL Tween 80; groups F10 and F20 – with 10 mL kg−1 suspensions containing fustin in two doses (10 mg kg−1 and 20 mg kg−1, respectively) and 50 μL Tween 80. After the treatment period, carrageenan was injected in the left hind paw and paw oedema was evaluated 0, 30, 60, 120, 180, 240, and 300 min after the injection using a plethysmometer. In the control group, paw oedema increased gradually and peaked at the 180th minute. Fustin treatment reduced the oedema in all time intervals and the effect was significant on the 30th and 60th minute after the injection. The present study indicated that fustin could suppress acute inflammation.

Promising La2Mo2O9-La2Mo3O12 Composite Oxygen-Ionic Electrolytes: Interphase Phenomena

The La₂Mo₂O₉-La₂Mo₃O₁₂ composite materials represent a novel class of highly conductive materials demonstrating increased oxygen-ion conductivity. Extensive research of (100 - x)La₂Mo₂O₉-xLa₂Mo₃O₁₂ composites over a wide range of concentrations (x = 5, 10, 15, 20, 30, and 100) was carried out for the first time. An increase in conductivity, oxygen surface exchange coefficient, and oxygen diffusivity is observed for composites compared to individual oxides, which is associated with the segregation of different ions on the surface of the grains and the formation of a La₅Mo₃O₁₆ new phase at the contact boundary of La₂Mo₂O₉ and La₂Mo₃O₁₂. 3D-modeling of the composite microstructure was performed on the basis of SEM-image analysis data in order to estimate the conductivity of the interphase layer between the La₂Mo₂O₉ and La₂Mo₃O₁₂ grains containing La₅Mo₃O₁₆. The electrical conductivity values of the composite materials calculated from a 3D-simulated microstructure and the experimentally measured conductivity correlate and demonstrate a composite effect.

Accurate non-invasive diagnosis and staging of non-alcoholic fatty liver disease using the urinary steroid metabolome

BACKGROUND

The development of accurate, non-invasive markers to diagnose and stage non-alcoholic fatty liver disease (NAFLD) is critical to reduce the need for an invasive liver biopsy and to identify patients who are at the highest risk of hepatic and cardio-metabolic complications. Disruption of steroid hormone metabolic pathways has been described in patients with NAFLD.

AIM(S)

To assess the hypothesis that assessment of the urinary steroid metabolome may provide a novel, non-invasive biomarker strategy to stage NAFLD.

METHODS

We analysed the urinary steroid metabolome in 275 subjects (121 with biopsy-proven NAFLD, 48 with alcohol-related cirrhosis and 106 controls), using gas chromatography-mass spectrometry (GC-MS) coupled with machine learning-based Generalised Matrix Learning Vector Quantisation (GMLVQ) analysis.

RESULTS

Generalised Matrix Learning Vector Quantisation analysis achieved excellent separation of early (F0-F2) from advanced (F3-F4) fibrosis (AUC receiver operating characteristics [ROC]: 0.92 [0.91-0.94]). Furthermore, there was near perfect separation of controls from patients with advanced fibrotic NAFLD (AUC ROC = 0.99 [0.98-0.99]) and from those with NAFLD cirrhosis (AUC ROC = 1.0 [1.0-1.0]). This approach was also able to distinguish patients with NAFLD cirrhosis from those with alcohol-related cirrhosis (AUC ROC = 0.83 [0.81-0.85]).

CONCLUSIONS

Unbiased GMLVQ analysis of the urinary steroid metabolome offers excellent potential as a non-invasive biomarker approach to stage NAFLD fibrosis as well as to screen for NAFLD. A highly sensitive and specific urinary biomarker is likely to have clinical utility both in secondary care and in the broader general population within primary care and could significantly decrease the need for liver biopsy.

P1572 The role of 3D echocardiography in the evaluation of left ventricular remodeling

Purpose

to assess the left ventricular (LV) remodeling with using transthoracic 3D Echo and MRI in young athletes.

Materials

for the period from October 2015 to April 2018, 88 athletes (61 men and 27 women) were examined. Mean age was 20.8 ± 3.9 years. Group A (professionals) – 65 athletes (4 or more training days a week, experience in sports for at least 7 years, the presence of at least the 1st sports category). Group B (Amateurs) – 23 athletes (3 or less training days a week). By types of loads were identified 4 groups: 1st - high-static, low-dynamic (climbing); 2nd - medium-static, medium-dynamic (volleyball, Rugby, sports dancing); 3rd - medium-static, high-dynamic (badminton, orienteering, hockey); 4th - high-static, high-dynamic (triathlon, water polo, rowing).

Methods

2D-, 3D-Echo was performed on Vivid E9 XDclear 4D (GE, USA). With the help of software package for processing 3D arrays (4D auto LVQ and 4D Strain and LV-mass) in automatic and semi-automatic mode was obtained end diastolic and end systolic volumes (EDV, ESV), ejection fraction (EF) and LV mass. The device was used for MRI - Avanto (Siemens) - 1.5 T, using: sensors for breathing and synchronization with ECG, standard surface coil Body Matrix. Visualization of the mobile myocardium was carried out by SSFP protocols in standard two-and four-chamber view, as well as on the short axis. In addition, the black-blood Protocol was performed in axial projection for visualization of mediastinal organs and chest. Evaluation of the results was performed on a workstation Syngo Via VB10B (Siemens) using a worker thread MR Cardiac analisis.

Results

There were significant differences in the types of loads (p < 0.001): 22% of men in Group B had 1st type, 2nd type - 78% of men and 93% of women in group B, 3rd type - 45% of men and 36% of women in group A, 4th type - 39% of men and 21% of women in group A. In the evaluation of LV remodeling and its relationship with the type of loads revealed significant differences (p < 0.01): 87.5% had LV remodeling (95.4% - aggregate type load 1, 2, 3), 6.8% - concentric remodeling (21.7% of all type 4), and 4.5% eccentric hypertrophy (8.7% of all type 4), 1.1 per cent of concentric hypertrophy (4.4% of all type 4). Consequently, most athletes with loads of type 4 had different types of LV remodeling. Comparing 3D Echo and MRI, high-grade positive correlations were obtained in indicators: EDV (R 0.82, p < 0.0001), ESV (R 0.80, p < 0.0001), LV mass (R 0.85, p < 0.0001), as well as moderate positive the index of EDV (R 0.54, p < 0.037) and unreliable for the EF.

Conclusions

three-dimensional visualization allows to carry out a reliable assessment of the volumetric parameters of the heart chambers, comparable with MRI data and to identify the signs and type of LV remodeling.

Requires further study of the performance of 3D Echo in athletes, given the lack of normative data on the modern stage.

10-million-elements-per-second printing of infrared-resonant plasmonic arrays by multiplexed laser pulses

We report on high-quality infrared (IR)-resonant plasmonic nanoantenna arrays fabricated on a thin gold film by tightly focused femtosecond (fs) laser pulses coming at submegahertz repetition rates at a printing rate of 10 million elements per second. To achieve this, the laser pulses were spatially multiplexed by fused silica diffractive optical elements into 51 identical submicrometer-sized laser spots arranged into a linear array at periodicity down to 1 μm. The demonstrated high-throughput nanopatterning modality indicates fs laser maskless microablation as an emerging robust, flexible, and competitive lithographic tool for advanced fabrication of IR-range plasmonic sensors for environmental sensing, chemosensing, and biosensing.

The research of electroconvulsive therapy effect on cognitive function in rats with depressive-like disorder formed by ultrasound

Electroconvulsive therapy (ECT) is effective method of resistant depression treatment. ECT activates neurotransmitter systems, increases neurotrophic factors production, induces neurogenesis. Nevertheless, ECT side effects, expressed as temporary amnesia, limit its application in clinical practice.

The objective of our work was to estimate rat's memory after ECT in the behavioral test: “Object recognition”, “Morris water-maze”.

The aim of the work was to research the effect of ECT on cognitive function in rats with depressive-like disorder and in normal rats.

Methods

The research was conducted with Sprague-Dawley rats (n = 41, 2 month age). Experimental stages:

– control group (n = 10) compared to control + ECT group ([70 mA, 50 Hz, 500 μsec; 10 days] n = 10);

– control group (n = 9) compared to group with depressive-like disorder, formed by ultrasound ([20–45 kHz; 21days] US, n = 6) and group with depressive-like disorder received ECT (n = 6).

Memory was estimated in the “Object recognition” and “Morris water-maze” tests.

Results

(1) ECT did not decrease cognitive function in the “Object recognition” test in normal rats (P = 0.1217). Also, it did not lead to cognitive impairments in the “Morris water-maze” test: time of platform searching did not differ significantly from the control group (P = 0.8573).

(2) ECT produced recovering effect on memory impairments of the US group in the “Object recognition” test (P = 0.0066). In the “Morris water-maze” ECT decreased time of platform searching by 7 times compared to the US group (P = 0.0025). That demonstrates the absence of ECT negative effect on rat's memory.

Conclusion

ECT does not produce negative effect on cognitive function in rats with depressive-like disorder and even recovers memory impairments.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Survival of patients (pts) with metastatic melanoma treated with the anti-CTLA4 monoclonal antibody (mAb) CP-675,206 in a phase I/II study

8524

Background: The fully human anti-CTLA4 mAb CP-675,206 has demonstrated clinical activity in pts with metastatic melanoma. Prolonged survival was observed in a prior single-dose phase I study, even in pts who did not achieve objective tumor responses. Methods: A multidose phase I/II trial was conducted in pts (N = 119) with histologically confirmed stage IIIc (unresectable) or stage IV recurrent metastatic melanoma and ECOG PS = 1. The study consisted of a phase I, open-label, multidose study (3, 6, and 10 mg/kg) and a phase I expansion cohort for HLA-A2.1+ pts (10 mg/kg monthly [Q1M]), followed by a phase II open-label study of 2 dosing regimens: 10 mg/kg Q1M and 15 mg/kg every 3 months (Q3M). The primary endpoint was safety in phase I, immune monitoring in the expansion cohort, and response in phase II. Survival was analyzed as a secondary endpoint. Results: In the phase I study, Kaplan-Meier estimates of median overall survival were 17.6 months for all dose groups combined (n = 28). In the phase II study, median survival was 10.3 months in the 10 mg/kg arm and 11.0 months in the 15 mg/kg arm. Survival outcomes were favorable, compared with historical median survival of 7 months, independent of whether pts achieved an objective response. Updated survival data will be presented. Conclusions: Patients participating in a multiple dose study of CP-675,206 showed a survival time that was greater than expected on historic controls. These observations support the endpoints of an ongoing randomized phase III study in melanoma to further evaluate survival in the frontline setting.

[Table: see text]

[Table: see text]

Results of a phase II clinical trial of 2 doses and schedules of CP-675,206, an anti-CTLA4 monoclonal antibody, in patients (pts) with advanced melanoma

3000

Background: CP-675,206 has antitumor activity in pts with metastatic melanoma. A 2-stage, 2-arm phase II trial was conducted to choose the optimal dosing regimen for pivotal clinical trial testing. Methods: Eligible pts had measurable melanoma (stage IIIc or IV) progressing on or after prior therapy with ECOG PS = 1. In stage 1, 18 pts per arm were randomized to either 10 mg/kg monthly (10 Q1M) or 15 mg/kg every 3 months (15 Q3M). If 3 or more pts in either arm had CR or PR, then 25 more pts were entered to that arm. Primary endpoint was objective tumor response, and secondary endpoints were safety and survival. Results: 89 pts received at least 1 dose (44 at 10 Q1M, 45 at 15 Q3M), with both study arms moving to stage 2. 96% of pts had stage IV disease, and 57% had elevated LDH. There were no significant differences in age, sex, stage, or baseline LDH levels between study groups. A median of 3 doses (range, 1 to 26) at 10 Q1M and 1 dose (range, 1 to 9) at 15 Q3M were administered with 100% compliance. Dose delays occurred in 30% of pts treated at 10 Q1M and 16% at 15 Q3M. 2 pts at 10 Q1M and 5 pts at 15 Q3M continued on study beyond 12 months (mo). To date, 6 pts at 10 Q1M have been discontinued due to toxicity (3 diarrhea/colitis [1 requiring colectomy], Grave’s ophthalmopathy, pancreatitis, hypersensitivity reaction) and 2 pts at 15 Q3M (colitis and pancreatitis, diarrhea) (P = 0.14). There were no toxic deaths. 15 Q3M was associated with lower incidence of grade 3 or 4 AEs (31% vs 41% at 10 Q1M; P = 0.42). Responses by investigator assessment were 1 CR and 3 PRs at 10 Q1M, and 1 CR and 2 PRs at 15 mg/kg Q3M, including responses in skin, LN, bone, liver, lung, and adrenal glands. To date, only 1 pt with PR at 10 Q1M has relapsed, and the remaining responses are ongoing (18+ to 28+ mo). Median survival is 10.3 mo at 10 Q1M and 11.0 mo at 15 Q3M (P = NS). Conclusions: The 15 mg/kg Q3M regimen was chosen for further clinical testing based on comparable antitumor efficacy and a trend to improved feasibility and safety compared with 10 mg/kg Q1M. CP-675,206 at this dose and schedule is being examined in pivotal phase II and III clinical trials for pts with melanoma, and in early phase II trials in pts with CRC and NSCLC.

No significant financial relationships to disclose.

A phase II study of the anti-CTLA4 monoclonal antibody (mAb), CP-675,206, in patients with refractory metastatic adenocarcinoma of the colon or rectum

3035

Background: The antitumor activity of antibodies to cytotoxic T lymphocyte-associated antigen 4 (CTLA4) has been demonstrated in a variety of murine tumor models, including rejection of established tumors and secondary exposure to tumor cells. This suggests that blockade of the inhibitory effects of CTLA4 can promote effective antitumor immune responses. CP-675,206 has also been shown to induce durable tumor responses in patients (pts) with metastatic melanoma in phase 1 and phase 2 clinical studies. The purpose of this study was to assess safety and efficacy of CTLA4 blockade with the fully human mAb CP-675,206 as single-agent therapy in pts with relapsed/ refractory colorectal cancer. Methods: A single-arm, multicenter, phase II trial of CP-675,206 was conducted in pts with measurable adenocarcinoma of the colon or rectum failing standard treatments and with an ECOG performance status of 0 or 1. Patients received 15 mg/kg Q90 days via IV infusion until disease progression. The primary objective was response rate by RECIST criteria. Secondary objectives included safety, duration of response, progression-free survival, and overall survival. Results: A total of 47 pts who received a median of 4 previous therapies (range, 1 to 9) were treated, and 46 experienced disease progression or death because of disease before reaching the planned second dose at 3 months. Grade 3 or 4 adverse events attributed to study drug were limited to diarrhea (n = 3, 6.4%) and idiopathic thrombocytopenia purpura (n = 1, 2.1%). Four pts (8.5%) had grade 2 diarrhea. Four pts received steroids and 2 received infliximab. One patient was removed for toxicity (diarrhea in the setting of what appeared to be treatment-related ulcerative colitis that was responsive to steroids). One patient (2%; 95% CI = 0%, 11%) had a stable ovarian mass and a substantial regression in an adrenal mass. This patient is continuing on study and has received a second dose. Conclusions: In heavily pretreated pts with colorectal cancer and good performance status, CP- 675,206 was tolerable. However, in this setting, CP-675,206 at 15 mg/kg did not demonstrate substantial single-agent activity.

No significant financial relationships to disclose.

Clearance of monoclonal antibody (mAb) CP-675,206 by therapeutic plasma exchange (TPE) or plasmapheresis

13515

Background: CP-675,206 is a fully human, cytotoxic T lymphocyte-associated antigen 4 (CTLA4) blocking mAb with immune stimulating properties under development for the treatment of metastatic melanoma. The pharmacokinetics of CP-675,206 is similar to endogenous IgG, with a long plasma half-life (22 days). We explored the use of TPE in two patients (pts) receiving CP-675,206, postulating that TPE could be used to remove mAb in cases where toxicities are thought to result from persistence of mAb in circulation. Methods: For both pts, five TPEs were performed over 7 days using a Cobe Spectra blood cell separator (TPE daily x 3, 2 days rest, and TPE daily x 2). One plasma volume was processed per TPE and replaced with a 60%/40% albumin/saline solution. Plasma CP-675,206 concentration was measured at baseline and after the 3rd and 5th TPE. Results: Patient 1 was a 62 year-old with metastatic melanoma who received 8 monthly doses of CP-675,206 (10 mg/kg). Six days after the last dose, the pt was found to have elevated ALT and bilirubin and detectable anti- smooth muscle and anti-microsomal antibodies. Based on a suspicion of therapy-related autoimmune hepatitis, the pt underwent TPE. Plasma CP-675,206 concentration declined by 96% following the 5th TPE, and ALT and bilirubin normalized over the 4 weeks following TPE with no other evidence of clinical hepatitis. Patient 2 was a 78 year-old with in-transit melanoma who received 3 monthly doses of CP-675,206 (10 mg/kg) and was responding to therapy. Two weeks after the last dose the pt developed diffuse bilateral arthralgias. The pt was diagnosed with rheumatoid factor-negative rheumatoid arthritis, presumably related to therapy with CP-675,206, and underwent TPE. Pre- and post-TPE plasma CP-675,206 concentrations are pending. The arthralgias persisted, and the pt subsequently received oral methotrexate with slow improvement in symptoms over the next 6 months. Conclusions: TPE is highly effective for reducing the plasma concentration of CP-675,206 and may be useful to avert the progression of drug-related adverse events. Clinical benefit from TPE may vary depending on the interval from dosing and may be limited by slow reversibility of T-cell immunostimulation.

[Table: see text]

Natural history of diarrhea associated with the anti-CTLA4 monoclonal antibody CP-675,206

3038

Background: Diarrhea resulting from immune activation has been associated with CTLA4 blockade. For example, in patients (pts) with stage IV melanoma receiving ipilimumab (MDX-010), a number of pts developed grade 3/4 autoimmune enterocolitis and severe diarrhea (Attia et al, 2005). In a single-dose phase I trial of CP-675,206 at doses up to 15 mg/kg in pts with solid tumors (n = 39), 9 instances of diarrhea were reported including 3 grade 3 events (Ribas et al, 2005). The incidence and severity of diarrhea was assessed in pts receiving CP- 675,206 in a large phase I/II study. Methods: An open-label phase I/II trial of CP-675,206 was conducted in pts with stage III (unresectable) or stage IV melanoma and an ECOG PS = 1. Diarrhea was assessed in pts treated at the phase II doses: 10 mg/kg monthly (Q1M) in phase I (n = 22), or 10 mg/kg Q1M (n = 44) or 15 mg/kg every 3 months (Q3M, n = 45) in phase II. Results: Medians of 3.5 doses (range, 1 to 18) at 10 mg/kg Q1M in phase I, 3 doses (range, 1 to 26) at 10 mg/kg Q1M in phase II, and 1 dose (range, 1 to 9) at 15 mg/kg Q3M were administered with 100% dose compliance. Treatment-related diarrhea was reported by 43 (39%) of 111 pts, and grade 3 diarrhea occurred in 14 (13%) pts. One patient had grade 4 colitis resulting in a colectomy. Diarrhea (all grades) occurred with similar frequency in each dose group; however, grade 3 treatment-related diarrhea occurred in 8% of pts treated with 15 mg/kg Q3M compared with 18% of pts treated with 10 mg/kg Q1M in phase I and 14% of pts treated with 10 mg/kg Q1M in phase II. Among 9 pts with an objective response, 8 experienced diarrhea (3 of which were grade 3). The majority of cases (65%) were mild to moderate in severity with a median time to onset of 51 days (range, 1 to 583 days) and resolution of 8 days (range, 1 to 182 days). More than half of pts who reported serious events of diarrhea were treated with steroids. Conclusions: Diarrhea associated with CP-675,206 was primarily mild to moderate in severity, transient, and manageable. In addition, 15 mg/kg Q3M may be better tolerated than 10 mg/kg Q1M. Ongoing clinical trials in pts with advanced melanoma will provide further information about the incidence, severity, and optimal management of diarrhea associated with CP-675,206.

No significant financial relationships to disclose.

Ex vivo blood stimulation assay as a translational research tool in the development of the ticilimumab (CP-675,206)

2542

Background: Cytotoxic T Lymphocyte-associated Antigen 4 (CTLA4) is an activation-induced T lymphocyte negative costimulatory receptor which down-regulates cellular immune responses. CTLA4 blockade may break peripheral immunological tolerance, leading to an effective immune response to cancer. Tools for assessing the effects of such a blockade are limited, as CTLA4 is not constitutively expressed on circulating T cells, and because activated lymphocytes are difficult to access in vivo. Therefore, we have employed ex vivo blood stimulation assays to define pharmacodynamic properties of the anti-CTLA4 antibody, ticilimumab. Methods: Ex vivo blood stimulation assays employed staphylococcal enterotoxin A (SEA) to stimulate isolated peripheral blood mononuclear cells (PBMC) or whole blood. Stimulation was monitored by production of interleukin 2 (IL-2). This assay was used preclinically to predict in vivo responses in animal models and in samples from cancer patients, as a batch release assay for production runs of ticilimumab, and clinically as a pharmacodynamic measurement in clinical trials of ticilimumab. Results: Screening experiments using the SEA assay allowed us to identify the lead candidate mAb with optimal CTLA4 blockade activity, ticilimumab. Dose-dependent increases in IL-2 production were observed in PBMC and whole blood samples up to an in vitro concentration of 100 ug/mL of ticilimumab, with 10 ug/mL identified as the minimum predicted efficacious concentration (Ceff). This functional potency assay was adapted for qualification of production lots of ticilimumab. Whole blood taken from cynomolgus monkeys dosed with ticilimumab demonstrated significant enhancement of IL-2 production at the same magnitude observed in in vitro experiments. Additionally, longitudinal samples taken from healthy volunteers and cancer patients suggested that an enhancement of 2.8 fold would be indicative of a pharmacodynamic effect of ticilimumab. Conclusions: The SEA assay provides a functional assessment of ticilimumab activity and can be used to guide the clinical development of this agent. Our data suggest that T cell reactivity is enhanced in the presence of ticilimumab in vitro, in primate models and in humans.

[Table: see text]

Dose and schedule selection for the anti-CTLA4 monoclonal antibody ticilimumab in patients (pts) with metastatic melanoma

8032

Background: Ticilimumab therapy has demonstrated anti-tumor activity in pts with metastatic melanoma. Its indirect, immune-mediated antitumor effects pose unique challenges for dose/regimen selection. Methods: It was our original intention to select the clinical dose/regimen of ticilimumab based on (1) clinical safety and tolerability and (2) attainment of target plasma concentrations derived from pre-clinical work using an ex vivo assay of ticilimumab-induced enhancement of cytotoxic T-cell function. Because numerous pts with metastatic melanoma experienced clinical benefit (i.e., durable objective responses [OR] and/or long-term survival) in early clinical trials of ticilimumab, we are using (1) safety and tolerability and (2) clinical benefit to guide dose/regimen selection. Data for evaluating these criteria come from a single-dose Phase 1 trial (0.01, 0.1, 1, 3, 6, 10 and 15 mg/kg) and an ongoing multiple-dose Phase 1/2 trial in pts with melanoma (Phase 1 portion: 3, 6 and 10 mg/kg Q1M; Phase 2 portion: 10 mg/kg Q1M and 15 mg/kg Q3M). Results: In the single-dose Phase 1 trial, 10 mg/kg was the Protocol-defined MTD but a high rate of clinical benefit was seen in the 15 mg/kg dose cohort (6/6 pts). Because the DLTs seen at 15 mg/kg (Gr 3 diarrhea, Gr 3 rash) were moderate and resolved completely within 3 months of dosing, 15 mg/kg Q3M was proposed as a safe and tolerable dose and is being studied in the Phase 2 portion of the multiple-dose Phase 1/2 trial. The Phase 1 portion of the multiple-dose Phase 1/2 trial revealed that 10 mg/kg is safe and tolerable with monthly dosing so 10 mg/kg Q1M is also being studied in the Phase 2 portion of the trial. At the end of the Simon Optimum-defined Stage 1 of the Phase 2 portion of the ongoing trial, the OR rate (3/18 pts) is the same for both dosing regimens. However, with 15 mg/kg Q3M, Gr 3/4 adverse events were less frequent (6% versus 34%). Conclusions: 15 mg/kg Q3M is proposed as the clinical dose/regimen for ticilimumab in metastatic melanoma. This dose/regimen appears to have anti-tumor activity approximately equal to 10 mg/kg Q1M but it appears to have a superior safety profile.

[Table: see text]

Phase I clinical trials of ticilimumab: Tumor responses are sufficient but not necessary for prolonged survival

8036

Background: Clinical studies examining anti-CTLA4 monoclonal antibodies (mAb) provide evidence of the biologic and clinical activity of this class of agents. Two Phase 1 studies with ticilimumab, a fully human anti-CTLA4 mAb, have been reported previously. In both studies, objective responses (OR) were seen in some patients (pts) with melanoma. In addition, we observed highly favorable outcomes among several pts who did not experience objective responses. This may indicate a positive impact of ticilimumab on melanoma in these pts, not well reflected by traditional response criteria. Long-term follow-up data on survival for pts enrolled in these Phase 1 studies is now reported. Methods: We studied the safety, pharmacokinetics, immunostimulatory activity, and clinical activity of ticilimumab in 53 pts with solid malignancies. Ticilimumab was administered, as a single agent, at single dose levels ranging from 0.01 to 15 mg/kg and at multiple dose levels ranging from 3 to 15 mg/kg. The dosing regimens included either a single dose, multiple doses given q3 months, or multiple doses given q1 month. Results: The two studies included 43 pts with measurable melanoma. Ticilimumab proved safe and overall was well tolerated (Ribas et al. ProcASCO 2005, and JCO Dec2005). Of the 43 pts with measurable melanoma, 18 were alive at >12 months (range: 13 - 42+) after initial treatment with ticilimumab. This includes 5 pts with an OR who continue on ticilimumab, either on-study or as part of a single IND, and 13 pts without an objective response. Among the pts who did not experience an OR, 5 had surgical resection of metastatic lesions and remain relapse free, and 8 are alive with disease. Conclusions: In pts with melanoma treated with ticilimumab, long-term survival has been achieved by all 5 pts who experienced an OR and in 13 pts who did not experience an OR. These findings suggest that lack of objective response is a poor predictor of long-term survival following ticilimumab therapy.

[Table: see text]

Potentially pathogenic features of heterotrophic plate count bacteria isolated from treated and untreated drinking water

Heterotrophic plate counts (HPCs) are commonly used to assess the general microbiological quality of drinking water. Drinking water quality specifications worldwide recommend HPC limits from 100 to 500 cfu ml(-1). A number of recent studies revealed evidence that these bacteria may not be as harmless as generally accepted. It appears that immuno-compromised individuals are particularly at risk. This would include the very young and very old patients with diseases such as AIDS and patients on therapy for purposes such as organ transplantation and cancer treatment. In this study, 339 bacterial colonies were isolated at random from selected treated and untreated drinking water in South Africa using routine heterotrophic plate count tests. In a first step to screen for potentially pathogenic properties, 188 (55.5%) of the isolates showed alpha- or beta-haemolysis on human- and horse-blood agar media. Subsequent analysis of the haemolytic isolates for enzymatic properties associated with pathogenicity revealed the presence of chondroitinase in 5.3% of the isolates, coagulase in 16.0%, DNase in 60.6%, elastase in 33.0%, fibrinolysin in 53.7%, gelatinase in 62.2%, hyaluronidase in 21.3%, lecithinase in 47.9%, lipase in 54.8% and proteinase in 64.4%. Fluorescein and pyocyanin were not produced by any of the isolates. Among the haemolytic isolates, 77.7% were resistant to oxacillin 1 microg, 59.6% to penicillin G 2 units, 47.3% to penicillin G 10 units, 54.3% to ampicillin 10 microg and 43.1% to ampicillin 25 microg. Cell culture studies revealed that 96% of haemolytic isolates were cytotoxic to HEp-2 cells, and 98.9% of the 181 cytotoxic isolates adhered to HEp-2 or Caco-2 cells. HEp-2 cells were invaded by 43.6%, and Caco-2 cells by 49.7%, of the 181 cytotoxic isolates. The invasion index on HEp-2 cells ranged from 1.9 x 10(-1) to 8.9 x 10(-6), whereas the invasion index on Caco-2 cells varied between 7.7 x 10(-2) and 8.3 x 10(-6). The most commonly isolated genera with these potentially pathogenic features were Aeromonas, Acinetobacter, Aureobacterium, Bacillus, Chryseobacterium, Corynebacterium, Klebsiella, Moraxella, Pseudomonas, Staphylococcus, Tsukamurella and Vibrio. The results obtained in this study support earlier findings on potentially pathogenic features of bacteria detected by routine HPCs on drinking water. These findings are in agreement with some epidemiological studies, which indicated an association between HPCs in drinking water and the incidence of gastroenteritis in consumers. However, the extent of the health risk concerned needs to be defined in more detail for meaningful revision of quality guidelines for HPCs in drinking water.

Kinetic differences in cardiac myosins with identical loop 1 sequences

The kinetics of nucleotide turnover vary considerably among isoforms of vertebrate type II myosin, possibly due to differences in the rate of ADP release from the nucleotide binding pocket. Current ideas about likely mechanisms by which ADP release is regulated have focused on the hyperflexible surface loops of myosin, i.e. loop 1 (ATPase loop) and loop 2 (actin binding loop). In the present study, we investigated the kinetic properties of rat and pig beta-myosin heavy chains (beta-MHC) in which we have found the sequences of loop 1 (residues 204-216) to be virtually identical, i.e. DQSKKDSQTPKG, with a single conservative substitution (rat E210D pig). Pig myocardium normally expresses 100% beta-MHC, whereas rat myocardium was induced to express 100% beta-MHC by surgical thyroidectomy and subsequent treatment with propylthiouracil. Slack test measurements at 15 degrees C yielded unloaded shortening velocities of 1.1 +/- 0.8 muscle lengths/s in rat skinned ventricular myocytes and 0.35 +/- 0.05 muscle lengths/s in pig skinned myocytes. Similarly, solution measurements at the same temperature showed that actin-activated ATPase activity was 2.9-fold greater for rat beta-myosin than for pig beta-myosin. Stopped-flow methods were then used to assess the rates of acto-myosin dissociation by MgATP both in the presence and absence of MgADP. Although the rates of MgATP-induced dissociation of acto-heavy meromyosin (acto-HMM) were virtually identical for the two myosins, the rate of ADP dissociation was approximately 3.8-fold faster for rat beta-myosin (135 s(-)(1)) than for pig beta-myosin (35 s(-)(1)). ATP cleavage rates were nearly 30% faster for rat beta-myosin. Thus, whereas loop 1 appears from other studies to be involved in nucleotide turnover in the pocket, our results show that loop 1 does not account for large differences in turnover kinetics in these two myosin isoforms. Instead, the differences appear to be due to sequence differences in other parts of the MHC backbone.

Regulation of force and unloaded sliding speed in single thin filaments: effects of regulatory proteins and calcium

1. Measurements of the unloaded sliding speed of and isometric force exerted on single thin filaments in in vitro motility assays were made to evaluate the role of regulatory proteins in the control of unloaded thin filament sliding speed and isometric force production. 2. Regulated actin filaments were reconstituted from rabbit F-actin, native bovine cardiac tropomyosin (nTm), and either native bovine cardiac troponin (nTn), troponin containing a TnC mutant, CBMII, in which the sole regulatory site in cardiac TnC (site II) is inactivated (CBMII-Tn), or troponin containing a point mutation in TnT (I79N, where isoleucine at position 79 is replaced with asparagine) associated with familial hypertrophic cardiomyopathy (FHC). 3. Addition of regulatory proteins to the thin filament increases both the unloaded sliding speed and the isometric force exerted by myosin heads on the thin filaments. 4. Variation of thin filament activation by varying [Ca2+] or the fraction of CBMII/TnC bound to the thin filament at pCa 5, had little effect on the unloaded filament sliding speed until the fraction of the thin filament containing calcium bound to TnC was less than 0.15. These results suggest that [Ca2+] primarily affects the number of attached and cycling crossbridges. 5. The presence of the FHC TnT mutant increased the thin filament sliding speed but reduced the isometric force that heavy meromyosin exerted on regulated thin filaments. These latter results, together with the increased sliding speed and isometric force seen in the presence of regulatory proteins, suggest that thin filament regulatory proteins exert significant allosteric effects on the interaction of crossbridges with the thin filament.

Influence of ochratoxin A and an extract of artichoke on the vaccinal immunity and health in broiler chicks

The combined effect of ochratoxin A (at diet levels of 130, 305 and 790 ppb) and penicillic acid was studied in 100 broiler chicks. Serological investigations revealed significantly lower haemagglutination inhibiting antibody titers in the experimental chicks immunized with vaccine against Newcastle disease. A statistically significant decrease of the body weight and the relative weight of lymphoid organs as well as a significant increase of the relative weight of kidneys and liver were seen. The main degenerative changes were observed in the proximal convoluted tubules in kidneys and slight degenerative changes were found in the hepatocytes. Degenerative changes and depletion of lymphoid cells were observed in the bursa Fabricii, thymus, spleen and Peyer's patches of intestinal mucosa. Serum analyses revealed significant decreases of the total protein and cholesterol, and significant increases of the uric acid and glucose. Haematological analyses showed a slight anaemia, leucocytosis and slightly decompensated metabolic acidosis. A statistically significant protective effect of 5% total water extract of artichoke on humoral immune response (increase of haemaglutination inhibiting antibody titer), relative organ weight as well as on pathomorphological, haematological and biochemical changes induced by ochratoxin A, was established.

Structural transition at actin's N-terminus in the actomyosin cross-bridge cycle

Force and motion generation by actomyosin involves the cyclic formation and transition between weakly and strongly bound complexes of these proteins. Actin's N-terminus is believed to play a greater role in the formation of the weakly bound actomyosin states than in the formation of the strongly bound actomyosin states. It has been the goal of this project to determine whether the interaction of actin's N-terminus with myosin changes upon transition between these two states. To this end, a yeast actin mutant, Cys-1, was constructed by the insertion of a cysteine residue at actin's N-terminus and replacement of the C-terminal cysteine with alanine. The N-terminal cysteine was labeled stoichiometrically with pyrene maleimide, and the properties of the modified mutant actin were examined prior to spectroscopic measurements. Among these properties, actin polymerization, strong S1 binding, and the activation of S1 ATPase by pyrenyl-Cys-1 actin were not significantly different from those of wild-type yeast actin, while small changes were observed in the weak S1 binding and the in vitro motility of actin filaments. Fluorescence changes upon binding of S1 to pyrenyl-Cys-1 actin were measured for the strongly (with or without ADP) and weakly (with ATP and ATPgammaS) bound acto-S1 states. The fluorescence increased in each case, but the increase was greater (by about 75%) in the presence of MgATP and MgATPgammaS than in the rigor state. This demonstrates a transition at the S1 contact with actin's N-terminus between the weakly and strongly bound states, and implies either a closer proximity of the pyrene probe on Cys-1 to structural elements on S1 (most likely the loop of residues 626-647) or greater S1-induced changes at the N-terminus of actin in the weakly bound acto-S1 states.

Functional consequences of troponin T mutations found in hypertrophic cardiomyopathy

Missense mutations in the cardiac thin filament protein troponin T (TnT) are a cause of familial hypertrophic cardiomyopathy (FHC). To understand how these mutations produce dysfunction, five TnTs were produced and purified containing FHC mutations found in several regions of TnT. Functional defects were diverse. Mutations F110I, E244D, and COOH-terminal truncation weakened the affinity of troponin for the thin filament. Mutation DeltaE160 resulted in thin filaments with increased calcium affinity at the regulatory site of troponin C. Mutations R92Q and F110I resulted in impaired troponin solubility, suggesting abnormal protein folding. Depending upon the mutation, the in vitro unloaded actin-myosin sliding speed showed small increases, showed small decreases, or was unchanged. COOH-terminal truncation mutation resulted in a decreased thin filament-myosin subfragment 1 MgATPase rate. The results indicate that the mutations cause diverse immediate effects, despite similarities in disease manifestations. Separable but repeatedly observed abnormalities resulting from FHC TnT mutations include increased unloaded sliding speed, increased or decreased Ca(2+) affinity, impairment of folding or sarcomeric integrity, and decreased force. Enhancement as well as impairment of contractile protein function is observed, suggesting that TnT, including the troponin tail region, modulates the regulation of cardiac contraction.