Simultaneous determination of the lactone and carboxylate forms of irintecan (CPT-11) and its actie metabolite SN-38 by high-performance liquid chromatography: Application to plasma pharmacokinetic studies in the rat.

Irinotecan (CPT-11) and its main metabolite SN-38 are potent anticancer derivatives of camptothecin (CPT), with active lactone and inactive carboxylate forms coexisting. A simple and sensitive HPLC method using the ion-pairing reagent tetrabutylammonium hydrogen sulfate (TBAHS) was developed to simultaneously determine all four analytes in rat plasma samples. Camptothecin (CPT) was used as internal standard. The mobile phase was 0.1 M potassium dihydrogen phosphate containing 0.01 M TBAHS (pH 6.4)–acetonitrile (75:25, v/v). Separation of the compounds was carried out on a Hypersil C18 column, monitored at 540 nm (excitation wavelength at 380 nm). All four compounds gave linear response as a function of concentration over 0.01–10 μM. The limit of quantitation in rat plasma was 0.01, 0.008, 0.005 and 0.005 μM for CPT-11 lactone, CPT-11 carboxylate, SN-38 lactone and SN-38 carboxylate, respectively. The method was successfully used in the study on the effect of coadministered thalidomide on the plasma pharmacokinetics of CPT-11 and SN-38 in rats. Coadministered thalidomide (100 mg/kg body weight by intraperitoneal injection) significantly increased the AUC_0–10h values of CPT-11 lactone and CPT-11 carboxylate by 32.6% and 30.3 %, respectively, (P < 0.01), but decreased the values by 19.2% and 32.4% for SN-38 lactone and carboxylate, respectively, (P < 0.05). Accordingly, the value of total body clearance (CL) of CPT-11 lactone was significantly lower in combination group compared to the control (1.329 versus 1.837 L/h/kg, P = 0.0002). Plasma t_1/2β values for SN-38 lactone and carboxylate were significantly (P < 0.01) smaller in rats with coadministered thalidomide, as compared to rats receiving CPT-11 alone. Further studies are needed to explore the underlying mechanisms for the observed kinetic interaction between CPT-11 and thalidomide.

Primary mathematics practice : the Victorian position

In order to establish what constitutes current primary practice in Victoria, video and other data were collected from a stratified random sample of ten year 3 and 4 classrooms in Victoria. Three video vignettes, representing the contrasting pedagogical flows captured on the videotapes, were produced to stimulate discussion in three separate Focus Groups of randomly selected teachers, principals, and mathematics teacher educators and consultants. This paper reports on their views of what constitutes current Victorian practice in primary mathematics

Being explicit about aspects of mathematics pedagogy

It is conventional wisdom that contextualising mathematics tasks can make them more meaningful for students, and that open-ended questions create opportunities for student engagement. Yet concerns are emerging that strategies such as these may exacerbate the disadvantage of some. We report data from a project that seeks to address such concerns by encouraging teachers to be explicit about aspects of their pedagogy. Men teachers were explicit about aspects of the pedagogy, the students responded in the direction intended.

Describing elements of mathematics lessons that accommodate diversity in student background

We are researching actions that teachers can take to improve mathematics learning for all students. Structural elements of the lessons being trialled include making aspects of pedagogy explicit to seek to overcome differences in familiarity with schooling processes, and sequencing tasks with the potential to engage students. This article reports research on teachers building learning communities by preparing variations to set tasks in order to address differences in students’ backgrounds.

Using word problems in Malaysian mathematics education: looking beneath the surface

This paper reports on aspects of a project that investigated the influence of Chinese Malaysian students’ schooling in a tradition of abstract, technical mathematics and rote learning on ways that they responded to mathematical word problems. Data from an action research project are reported. Supposedly “shallow” and “ deep” learning are shown to be interlinked, and assumptions frequently made by Western educators about modelling and practice are questioned.

Planning and teaching mathematics lessons as a dynamic, interactive process

We are researching actions that teachers can take to improve mathematics learning for all students, with particular attention to specific groups of students who might experience difficulty. After identifying possible barriers to learning, we offered teachers mathematics lessons structured in a particular way. Teachers’ use of the model outlined in this paper seemed productive and their resulting planning and teaching proved to be dynamic and interactive. This paper uses excerpts from a conversation between two teachers to illustrate specific aspects of the model.

Developing guidelines for teachers helping students experiencing difficulty in learning mathematics

As part of an ongoing project, we have developed a model of planning and teaching that is designed to assist teachers to help students overcome barriers they might experience in learning mathematics. The following is a discussion of one aspect of the model that we term “enabling prompts”. These refer to the directions, invitations, or questions that a teacher offers when interacting one-on-one with students experiencing difficulties. We argue that teachers should plan to pose subsidiary questions in the first instance, rather than, for example, offering further explanations. We outline our overall planning and teaching model, we present some examples of enabling prompts used by our project teachers, and we propose some considerations for teachers when structuring their own enabling prompts.

Sociocultural research on mathematics education : an international perspective

This volume--the first to bring together research on sociocultural aspects of mathematics education--presents contemporary and international perspectives on social justice and equity issues that impact mathematics education. In particular, it highlights the importance of three interacting and powerful factors--gender, social, and cultural dimensions. Sociocultural Research on Mathematics Education: An International Perspective is distinguished in several ways:

* It is research based. Chapters report on significant research projects; present a comprehensive and critical summary of the research findings; and offer a critical discussion of research methods and theoretical perspectives undertaken in the area.
* It is future oriented, presenting recommendations for practice and policy and identifying areas for further research.
* It deals with all aspects of formal and informal mathematics education and applications and all levels of formal schooling.

As the context of mathematics education rapidly changes-- with an increased demand for mathematically literate citizenship; an increased awareness of issues of equity, inclusivity, and accountability; and increased efforts for globalization of curriculum development and research-- questions are being raised more than ever before about the problems of teaching and learning mathematics from a non-cognitive science perspective. This book contributes significantly to addressing such issues and answering such questions. It is especially relevant for researchers, graduate students, and policymakers in the field of mathematics education.