Population pharmacokinetics of plasma-derived factor IX: procedures for dose individualization

BACKGROUND

Population pharmacokinetic (POPPK) models describing factor IX (FIX) activity levels in plasma, in combination with individual FIX measurements, may be used to individualize dosing in the treatment of hemophilia B.

OBJECTIVES

The aim was to reevaluate a previously developed POPPK model for FIX activity and to explore the number and timing of FIX samples required in pharmacokinetic (PK) dose individualization.

METHODS

The POPPK model was reevaluated using an extended data set. Several sampling schedules, varying with respect to the timing and number of samples, were evaluated in a simulation study with relative dose errors compared between schedules. The performance of individually calculated doses was compared with commonly prescribed FIX doses with respect to the number of patients with a trough FIX activity > 0.01 U mL(-1) .

RESULTS AND CONCLUSIONS

A three-compartment PK model best described the FIX activity levels. The number and timing of samples greatly influenced imprecision in dose prediction. Schedules with single samples taken on both day 2 and day 3 were identified as being convenient schedules with an acceptable performance level. Individually calculated doses performed better with respect to patient target attainment than a fixed 40 U kg(-1) dose regardless of how many samples were available to calculate individual doses. The results of this study suggest that PK dose tailoring with limited sampling may be applicable for plasma-derived FIX products.

Macronutrient intake regulates sexual conflict in decorated crickets

Sexual conflict results in a diversity of sex-specific adaptations, including chemical additions to ejaculates. Male decorated crickets (Gryllodes sigillatus) produce a gelatinous nuptial gift (the spermatophylax) that varies in size and free amino acid composition, which influences a female's willingness to fully consume this gift. Complete consumption of this gift maximizes sperm transfer through increased retention of the sperm-containing ampulla, but hinders post-copulatory mate choice. Here, we examine the effects of protein (P) and carbohydrate (C) intake on the weight and amino acid composition of the spermatophylax that describes its gustatory appeal to the female, as well as the ability of this gift to regulate sexual conflict via ampulla attachment time. Nutrient intake had similar effects on the expression of these traits with each maximized at a high intake of nutrients with a P : C ratio of 1 : 1.3. Under dietary choice, males actively regulated their nutrient intake but this regulation did not coincide with the peak of the nutritional landscape for any trait. Our results therefore demonstrate that a balanced intake of nutrients is central to regulating sexual conflict in G. sigillatus, but males are constrained from reaching the optima needed to bias the outcome of this conflict in their favour.

Meta-analysis of reconstruction techniques after low anterior resection for rectal cancer

BACKGROUND

Options for reconstruction after low anterior resection (LAR) for rectal cancer include straight or side-to-end coloanal anastomosis (CAA), colonic J pouch and transverse coloplasty. This systematic review compared these techniques in terms of function, surgical outcomes and quality of life.

METHODS

A systematic literature search (MEDLINE, Embase and the Cochrane Library, from inception of the databases until November 2014) was conducted to identify randomized clinical trials comparing reconstructive techniques after LAR. Random-effects meta-analyses were carried out, and results presented as weighted odds ratios or mean differences with corresponding 95 per cent c.i. A network meta-analysis was conducted for the outcome anastomotic leakage.

RESULTS

The search yielded 965 results; 21 trials comprising data from 1636 patients were included. Colonic J pouch was associated with lower stool frequency and antidiarrhoeal medication use for up to 1 year after surgery compared with straight CAA. Transverse coloplasty and side-to-end CAA had similar functional outcomes to the colonic J pouch. No superiority was found for any of the techniques in terms of anastomotic leak rate.

CONCLUSION

Colonic J pouch and side-to-end CAA or transverse coloplasty lead to a better functional outcome than straight CAA for the first year after surgery.

Chimerism, graft survival, and withdrawal of immunosuppressive drugs in HLA matched and mismatched patients after living donor kidney and hematopoietic cell transplantation

Thirty-eight HLA matched and mismatched patients given combined living donor kidney and enriched CD34(+) hematopoietic cell transplants were enrolled in tolerance protocols using posttransplant conditioning with total lymphoid irradiation and anti-thymocyte globulin. Persistent chimerism for at least 6 months was associated with successful complete withdrawal of immunosuppressive drugs in 16 of 22 matched patients without rejection episodes or kidney disease recurrence with up to 5 years follow up thereafter. One patient is in the midst of withdrawal and five are on maintenance drugs. Persistent mixed chimerism was achieved in some haplotype matched patients for at least 12 months by increasing the dose of T cells and CD34(+) cells infused as compared to matched recipients in a dose escalation study. Success of drug withdrawal in chimeric mismatched patients remains to be determined. None of the 38 patients had kidney graft loss or graft versus host disease with up to 14 years of observation. In conclusion, complete immunosuppressive drug withdrawal could be achieved thus far with the tolerance induction regimen in HLA matched patients with uniform long-term graft survival in all patients.

Prophylactic Swallowing Exercises in Head and Neck Cancer Radiotherapy

Many head and neck cancer (HNC) survivors experience reduced quality of life due to radiotherapy (RT)-related dysphagia. The aim of this prospective randomized trial was to evaluate the impact of prophylactic swallowing exercises on swallowing-related outcomes in HNC patients treated with curative RT. Patients treated with primary RT for HNC were candidates for this randomized protocol. Participants in the exercise group were instructed to perform swallowing exercises at home. Participants in the control group were given standard care. Patients were evaluated with modified barium swallow and several other secondary outcome measures at four and nine different time points, respectively. Data were analyzed according to intention-to-treat analyses. A total of 44 consecutive patients were included; 22 in each group. In general, there was no difference between the two groups regarding any of the dysphagia outcomes during and after treatment. Adherence to exercises was poor and dropouts due to especially fatigue were very frequent in both groups. Systematic swallowing exercises had no impact on swallowing outcomes within the first year after RT. Despite repeated supervised sessions, adherence to exercises was a major issue and dropouts were frequent in both the intervention and control group.

Abstract 4568: A new quantitative in-situ IHC method - validation of analytical performance

Background

In routine pathology, in situ quantification of protein in formalin-fixed, paraffin-embedded (FFPE) tissue is limited to immunohistochemistry (IHC) which is semi-quantitative at best. Accurate and robust measurement of protein expression in FFPE samples, without loss of morphological information, is currently not achievable. Quantitative protein assessment of FFPE tissue can be destructive, and/or time consuming with risk of analyzing non-relevant tissue due to heterogeneity.

We have developed a new reliable quantitative IHC (qIHC) method based on a novel amplification system that enables quantification of protein directly in FFPE tissue by counting dots using a standard bright field microscope. The qIHC method combines the ease, speed and morphological information gained from classical IHC staining together with quantitative assessment of protein expression in situ.

The goal of this study was to assess the analytical performance of qIHC in a HER2 assay analyzing both FFPE cell pellets and breast cancer specimens.

Methods

Five different cell lines with HER2 expression ranging from undetectable with IHC to strongly positive (IHC 3+) were used as test samples. Flow cytometry, and ELISA were used as reference methods to confirm protein expression levels and stability of the cell lines. The qIHC assay was conducted using an automated Autostainer Link 48 stainer, and quantitative assessment was done by counting dots per cell using an image analysis algorithm. Repeatability, reproducibility, robustness, linearity, sensitivity, and quantification limits were evaluated.

In addition, 44 breast cancer specimens were stained to compare standard HER2 IHC with qIHC.

Results

We validated the quantitative test through testing for accuracy, reproducibility, repeatability, robustness, and precision. Each of the different tests showed statistical significant results (p: <0.0001-0.005).

The dynamic range and linearity of the assay were investigated by correlating the qIHC results to an in-house-developed flow cytometry assay as well as an FDA-approved ELISA kit for HER2 measurement. All tests demonstrated statistically significant correlation (p: 0.0002-0.0045). No overlap was seen between the different cell lines and a broad dynamic range could be demonstrated ranging from 1*103 receptors/cell up to 2.5*106 receptors/cell. Furthermore, HER2 was clearly detectable above background in the low expression cell line MDA-MB-468, thus showing the inherent high sensitivity of the qIHC assay.

To demonstrate the capability of the qIHC assay in tumor tissue, we tested the qIHC concordance to HER2 IHC in 44 breast cancer specimens. We confirmed a strong correlation between IHC and qIHC (p: <0.0001).

Conclusions

The results show that qIHC provides a highly sensitive, accurate, quantitative, and reliable assay for protein expression in FFPE tissue, which could provide better and more precise diagnosis and thus improved personalized cancer treatment.

Citation Format: Kristian Jensen, Rikke M. Jørgensen, Kenneth H. Petersen, Jesper Lohse, Helene Derand. A new quantitative in-situ IHC method - validation of analytical performance. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4568. doi:10.1158/1538-7445.AM2014-4568

Immunolocalization of human alpha-synuclein in the Thy1-aSyn ("Line 61") transgenic mouse line

Alpha-synuclein (a-syn) is the major component of the intracytoplasmic inclusions known as Lewy bodies (LB), which constitute the hallmark of Parkinson's disease (PD). Mice overexpressing human a-syn under the Thy-1 promoter (ASO) show slow neurodegeneration and some behavioral deficits similar to those seen in human PD patients. Here, we describe a whole-brain distribution of human a-syn in adult ASO mice. We find that the human a-syn is ubiquitously distributed in the brain including the cerebellar cortex, but the intensity and sub-cellular localization of the staining differed in the various regions of the central nervous system. Among particular CNS areas with human a-syn immunoreactivity, we describe staining patterns in the olfactory bulb, cortex, hippocampus, thalamic region, brainstem nuclei and cerebellar cortex. This immunohistochemical study provides an anatomical map of the human a-syn distribution in ASO mice. Our data show that human a-syn, although not present at levels that were detectable by immunostaining in dopaminergic neurons of substantia nigra or noradrenergic neurons of locus coeruleus, was highly expressed in other PD relevant regions of the brain in different neuronal subtypes. These data will help to relate a-syn expression to the phenotypic manifestations observed in this widely used mouse line.

Cavity-enhanced room-temperature magnetometry using absorption by nitrogen-vacancy centers in diamond

We demonstrate a cavity-enhanced room-temperature magnetic field sensor based on nitrogen-vacancy centers in diamond. Magnetic resonance is detected using absorption of light resonant with the 1042 nm spin-singlet transition. The diamond is placed in an external optical cavity to enhance the absorption, and significant absorption is observed even at room temperature. We demonstrate a magnetic field sensitivity of 2.5  nT/Hz, and project a photon shot-noise-limited sensitivity of 70  pT/Hz for a few mW of infrared light, and a quantum projection-noise-limited sensitivity of 250  fT/Hz for the sensing volume of ∼90  μm×90  μm×200  μm.

The influence of surface on the running velocities of elite and amateur orienteer athletes

We compared the reduction in running velocities from road to off-road terrain in eight elite and eight amateur male orienteer athletes to investigate whether this factor differentiates elite from amateur athletes. On two separate days, each subject ran three 2-km time trials and three 20-m sprints "all-out" on a road, on a path, and in a forest. On a third day, the running economy and maximal aerobic power of individuals were assessed on a treadmill. The elite orienteer ran faster than the amateur on all three surfaces and at both distances, in line with their better running economy and aerobic power. In the forest, the elites ran at a slightly higher percentage of their 2-km (∼3%) and 20-m (∼4%) road velocities. Although these differences did not exhibit traditional statistical significance, magnitude-based inferences suggested likely meaningful differences, particularly during 20-m sprinting. Of course, cognitive, mental, and physical attributes other than the ability to run on different surfaces are required for excellence in orienteering (e.g., a high aerobic power). However, we suggest that athlete-specific assessment of running performance on various surfaces and distances might assist in tailoring training and identifying individual strengths and/or weaknesses in an orienteer.

An enigmatic new tapeworm, Litobothrium aenigmaticum, sp. nov. (Platyhelminthes : Cestoda : Litobothriidea), from the pelagic thresher shark with comments on development of known Litobothrium species

An enigmatic new tapeworm is described from pelagic thresher sharks in México and Taiwan. While lsrRNA (D1-D3) data robustly place it in the Litobothriidea, it bears essentially no morphological resemblance to other members of the order. Instead it superficially resembles the freshwater fish-inhabiting Caryophyllidea. Its scolex consists of a simple dome-shaped scolex proper and an extensive cephalic peduncle housing four distinct tissue types. It is hyperapolytic, thus reproductive anatomy is unknown. Developmental data show typical litobothriideans bear basic elements of their adult scolex upon entering the definitive host, undermining the notion that the new cestode represents a distinct litobothriidean life cycle stage. Scanning electron microscopy revealed the new species shares bands of distinctive microtriches with its congeners. In combination these data justify establishment of Litobothrium aenigmaticum, sp. nov.; the generic, familial and ordinal diagnoses are emended accordingly. Unlike typical litobothriideans, each worm is associated with a mucosal expansion at its attachment site, like those seen in some caryophyllideans. This pathological change may represent a worm-induced host response serving to reinforce attachment of the simple scolex to the mucosa. If so, the convergence of this litobothriidean on a morphology like that seen in the distantly related Caryophyllidea is a result of similarity in mode of attachment.