Communication with young people in paediatric and adult endocrine consultations: an intervention development and feasibility study.

BACKGROUND: Communication is complex in endocrine care, particularly during transition from paediatric to adult services. The aims of this study were to examine the feasibility of interventions to support young people to interact with clinicians. METHODS: Development and evaluation of a complex intervention in 2 phases: Pre-intervention observational study; Intervention feasibility study. Purposive sample of recordings of 62 consultations with 58 young people aged 11-25 years with long-term endocrine conditions in two paediatric and two adult endocrine clinics. Proportion of time talked during consultations, number and direction of questions asked; Paediatric Consultation Assessment Tool (PCAT); OPTION shared decision making tool; Medical Information Satisfaction Scale (MISS- 21). Young people were invited to use one or more of: a prompt sheet to help them influence consultation agendas and raise questions; a summary sheet to record key information; and the www.explain.me.uk website. RESULTS: Nearly two thirds of young people (63%) chose to use at least one communication intervention. Higher ratings for two PCAT items (95% CI 0.0 to 1.1 and 0.1 to 1.7) suggest interventions can support consultation skills. A higher proportion of accompanying persons (83%) than young people (64%) directed questions to clinicians. The proportion of young people asking questions was higher (84%) in the intervention phase than in the observation phase (71%). CONCLUSIONS: Interventions were acceptable and feasible. The Intervention phase was associated with YP asking more questions, which implies that the availability of interventions could promote interactivity.

Mucopolysaccharidosis I; Parental beliefs about the impact of disease on the quality of life of their children.

BACKGROUND: Hematopoietic stem cell transplants, alongside enzyme replacement therapy and good multi-disciplinary care, have dramatically improved the life expectancy in children with Mucopolysaccharidosis (MPS) I, with better objective and functional outcomes. Despite these improvements, children with both the attenuated (non-Hurler) and severe (Hurler) variants of the disease have marked residual morbidity. Children with MPS I suffer with head and neck disease including obstructive sleep apnoea and hearing loss. The impact of these on quality of life has been poorly researched and no previous work has been published looking at patients' perception of their own health, an important domain when considering the impact of treatment. METHODS: This exploratory qualitative study aimed to discover the effect of head and neck disease, alongside that of MPS I as a whole, on the quality of life of affected children. A grounded theory approach was used to conduct this study. Children and their parents were invited to participate in semi-structured interviews. The transcribed interviews were coded and emergent themes explored until saturation occurred. RESULTS: The families of eleven children with MPS I were interviewed, five with Hurler's and six with the attenuated non-Hurler's. Important themes to emerge were- the fear of dying associated with obstructive sleep apnoea, difficulties communicating at school due to the delayed acquisition of language, chronic pain and restricted mobility, physical differences and restricted participation in social activities such as sports secondary to the musculoskeletal disease burden. The overall theme running through the analysis was the desire to fit in with ones peers. CONCLUSION: Parents and children with MPS 1 worry about 'fitting-in' with broader society. The presence of airway disease has a profound impact on the emotional well being of parents whilst language delay and musculoskeletal disease have the biggest impact on the quality of life of the children themselves. It is important to understand the impact of MPS I on the quality of life of children and their families so that we may improve future treatment and management of this sub-group of children who have an increasing life span.

The use of qualitative methods to inform Delphi surveys in core outcome set development.

BACKGROUND: Core outcome sets (COS) help to minimise bias in trials and facilitate evidence synthesis. Delphi surveys are increasingly being used as part of a wider process to reach consensus about what outcomes should be included in a COS. Qualitative research can be used to inform the development of Delphi surveys. This is an advance in the field of COS development and one which is potentially valuable; however, little guidance exists for COS developers on how best to use qualitative methods and what the challenges are. This paper aims to provide early guidance on the potential role and contribution of qualitative research in this area. We hope the ideas we present will be challenged, critiqued and built upon by others exploring the role of qualitative research in COS development. This paper draws upon the experiences of using qualitative methods in the pre-Delphi stage of the development of three different COS. Using these studies as examples, we identify some of the ways that qualitative research might contribute to COS development, the challenges in using such methods and areas where future research is required. RESULTS: Qualitative research can help to identify what outcomes are important to stakeholders; facilitate understanding of why some outcomes may be more important than others, determine the scope of outcomes; identify appropriate language for use in the Delphi survey and inform comparisons between stakeholder data and other sources, such as systematic reviews. Developers need to consider a number of methodological points when using qualitative research: specifically, which stakeholders to involve, how to sample participants, which data collection methods are most appropriate, how to consider outcomes with stakeholders and how to analyse these data. A number of areas for future research are identified. CONCLUSIONS: Qualitative research has the potential to increase the research community's confidence in COS, although this will be dependent upon using rigorous and appropriate methodology. We have begun to identify some issues for COS developers to consider in using qualitative methods to inform the development of Delphi surveys in this article.

Risks and benefits of ventilation tubes and hearing aids from the perspective of parents of children with cleft palate.

OBJECTIVE: To understand parents' experiences of treatment of otitis media with effusion (OME) for children with cleft palate. METHODS: Qualitative interviews with parents of 37 children who had non-syndromic cleft palate (with or without cleft lip). They were recruited from two cleft centres in northern England. Participants talked about choices, information, decision-making and satisfaction with ventilation tubes (VTs) and/or hearing aids (HAs). Interviews were recorded and transcribed verbatim. Themes were developed using Framework Analysis. RESULTS: VTs and HAs were not considered as equal treatments by interviewees, due to physical risks associated with the former and social consequences with the latter. The inequality was explained within three main themes: (1) treatment recommendations - most parents did not recall being offered options when OME was first treated; VTs tended to be presented initially followed by HAs if VTs had been inserted more than once. Treatment recommendations came from medical specialists, although participants could also be influenced by other parents' stories; (2) beliefs about mechanisms of treatments - interviewees believed VTs could address the underlying cause of OME by draining fluid. Some parents felt HAs signified a deterioration in hearing and an escalation of care. Improvements in hearing were reported by interviewees with VTs and HAs; (3) demands on parents - participants often saw the insertion of VTs as opportunistic, alongside another procedure (e.g. palatal closure). They could feel disappointed when VTs fell out or were perceived to have caused ear infections. Parental involvement was on-going for HAs (e.g. ordering batteries and tubes). Parents expressed fears about the potential for social stigma of HAs, although none reported significant teasing of children because they wore HAs. CONCLUSIONS: Parents' views about treatment for OME were shaped by differing perceptions about anticipated risks and benefits. VTs may have been seen as a simple fix, inserted alongside another procedure, but some interviewees had concerns about possible physical consequences. Others were more worried about anticipated social stigma associated with HAs. However, parents of children who wore a HA described them as easy to manage and well tolerated, at least until children got older and started to comment on their appearance.

Supporting the care of children with diabetes in school: a qualitative study of nurses in the UK.

AIMS: Intensification of diabetes management in children and young people has implications for schools. The aim of this study was to examine the role of nurses in supporting care of children with diabetes in schools and early years settings. METHODS: The qualitative design incorporated focus groups and individual telephone interviews with nurses who were unavailable to participate in focus groups. A purposive sample of 47 nurses from acute and community settings, participated in eight focus groups and eight telephone interviews. Data were analysed through a process of constant comparison. RESULTS: Nurses identified an ambiguous and inadequate legal and policy framework. The responses of schools were variable and unpredictable because the views of head teachers determined the level of cooperation. School staff could lack basic knowledge about Type 1 diabetes. Relationships between school staff and parents could also affect their willingness to provide support for diabetes care. The skills of negotiating appropriate support for children with diabetes were learnt by experience rather than through formal training or evidence-based guidance. Nurses' accounts demonstrated uncertainties about: what could be required of schools; how schools would respond; individual responsibilities; and about what constituted best practice. CONCLUSIONS: There is a need for more evidence about how healthcare providers can influence schools and about the most cost-effective use of nurses to support the management of children with diabetes in schools.

The effectiveness of self-care support interventions for children and young people with long-term conditions: a systematic review.

Children's health policy has highlighted the need to develop self-care programmes. However, there is a lack of evidence on which to base the development of such programmes. This paper reviews the published research on the effectiveness of self-care support interventions for children and young people with asthma, cystic fibrosis and diabetes. A systematic search was conducted of a range of electronic databases, supplemented by searching the reference lists of retrieved papers and published reviews. Retrieved studies were assessed against quality and eligibility criteria by two independent reviewers. The results were narratively synthesized to examine the effectiveness of self-care support interventions on health status, psycho-social well-being, condition-related knowledge, health service use and participant satisfaction. The search strategy identified 4261 papers which were screened against the review inclusion criteria. A total of 194 papers were assessed as being potentially eligible for inclusion with 15 papers being judged as adequate to include in the review. There is strong evidence of the effectiveness of interventions that target children/young people; use e-health or group-based methods; that are delivered in community settings. There is no evidence that interventions that focus on parents alone or are delivered only in hospital settings are effective. While there is some evidence to inform the development of self-care support programmes, there is a need for well-designed trials of interventions that are feasible to transfer into real-life settings and which involve parents and children in their development.

School children's own views, roles and contribution to choices regarding diet and activity in Spain.

BACKGROUND: Behaviours regarding food and activity are learned during childhood and continue throughout life. Children can be very important agents in making decisions concerning their own well-being and care and their perspective is essential to understanding how they and/or others make choices for them to achieve a healthy lifestyle. However, their perspectives remain under-researched. This study provides an insight into school children's own perspectives, behaviours and contribution to food and activity choices. METHODS: The paper reports on the findings from an ethnographic study with 38 Spanish children aged 5-7 years. Information was obtained through participant observations, diaries kept by children and group interviews. Data were analysed using techniques of analytical induction and constant comparison. RESULTS: The children who took part in this study described choices about activities with enthusiasm. Children saw activity as a way of learning new things, mastering skills and socializing. They were willing to try and experience new activities and games. However, the activities performed depended on parents' agendas and security issues. In contrast, children reported less interest in and active involvement in food choices. They contributed to family food choices indirectly through the expression of their preferences, not wanting to eat what they disliked or tasting new foods. CONCLUSION: Children had strong preferences and motivations, particularly about activities which could be harnessed in interventions to prevent obesity and promote healthy diet and activity. Parental involvement and commitment is also important both to encourage exercise according to children's interests and active informed food choices, including introduction to unfamiliar foods.

Parenting children requiring complex care: a journey through time.

BACKGROUND: Parents of children requiring complex care provide intense and demanding care in their homes. Unlike professionals who provide similar care in institutions, parents may not receive regular breaks from care giving. As a result, parents, over time, experience health and social consequences related to care giving. Respite care, one form of a break from care giving, is frequently cited as an unmet need by such parents. METHOD: Given the paucity of literature on the impact of care giving over time, an ethnographic approach that involved in-depth interviews, participant observation, eco-maps, and document review was used. Parents of children requiring complex care, nurses and social workers participated in the study. RESULTS: A developmental map of care giving over time was constructed from the parents' retrospective accounts of parenting a child requiring complex care. The developmental map describes the trajectory of care for the children from infancy through young adulthood and the parents' evolving needs for respite care. CONCLUSION: Existing literature focuses on the day-to-day experiences of parents, who are carers, rather than their experiences over time. As parents of children requiring complex care are providing care from infancy through the death of either child or parent, respite needs will change. This developmental map identifies how a group of parents reported these changes in care giving and their perceived needs for respite care.

Weight and energy: parents' and children's perspectives on managing cystic fibrosis diet.

AIMS: To explore the meanings that parents and children attach to food and eating, and how these influence their approaches to dietary management of cystic fibrosis (CF). METHODS: Ethnographic design using in-depth interviews with 32 children with CF (aged 6-14 years) and their parents, and participant observations during visits to CF clinics with a sub-group of 21 children. Data were analysed using the constant comparative method and theoretical sampling was used to further explore and develop emergent themes. RESULTS: Dietary management was found to be a demanding task for children and their parents, and priorities differed between them. A priority of feeding for parents was to protect their children's long term physical health and survival by keeping their weight up. A challenge for parents was to ensure their children's cooperation with eating. A priority for children in being healthy was to have energy for physical activities and so energy rather than weight was of immediate relevance to their daily lives. These differences between parents and children gave rise to tensions and conflicts in their interactions with one another in managing diet. CONCLUSIONS: Healthcare professionals should take account of the meanings that children and their parents attach to food and eating that can influence their decisions about implementing CF dietary recommendations. The role of children in making food choices has implications for acknowledging them as active participants in their dietary care and for adopting child centred approaches to dietary advice for CF.

Re-thinking family-centred care across the continuum of children's healthcare.

BACKGROUND: The terms family-centred care (FCC) and family-centred services (FCS) are used interchangeably across the continuum of children's healthcare to encompass concepts of: parental participation in children's healthcare; partnership and collaboration between the healthcare team and parents in decision-making; family-friendly environments that normalize as much as possible family functioning within the healthcare setting; and care of family members as well as of children. However, authors from different professional and policy perspectives have used different definitions and literatures when arguing the evidence for FCC and FCS. METHOD: A critical literature review and theoretical discussion exploring common concepts and issues forming the basis for a research agenda further strengthening of the evidence base for FCC. A systematic identification of constructs, concepts and empirical indicators is developed and applied to exemplars in pain and asthma that span the continuum of children's healthcare across acute and community settings. CONCLUSIONS: The extent to which the concepts are supported by research and applied in practice remains unclear. We propose that re-thinking of FCC is required in order to develop a more coherent programme of research into the application of FCC theory in children's healthcare.

Different meanings of respite: a study of parents, nurses and social workers caring for children with complex needs.

AIM: To examine the meaning of respite care to parents of children with complex conditions and providers. METHODS: In-depth interviews, participant observation and document review were used to collect data from nineteen mothers and seven fathers of children between the ages of 8 and 16 years who required complex care and from their respite providers, including thirteen nurses, and four social workers from three counties in North-west England. RESULTS: Parents described three categories of respite: short breaks provided by the extended family or friends, short breaks (3-4 h) by an outside agency, and overnight respite outside of home. They highly valued overnight respite outside the home. There was some overlap but also notable differences between parents' and providers' categorizations of respite care and the value attached to different forms of respite provision. Parents and nurses valued overnight respite outside the home unlike social workers who preferred to provide respite without separating children from their families. DISCUSSION: Appropriate provision of respite care and communication with parents requires understanding of the meaning of respite to parents. The meanings attached to respite care by parents and providers should be considered in attempts to understand and address problems of inappropriate provision and/or dissatisfaction with respite services.

Enhancing the rigor of grounded theory: incorporating reflexivity and relationality.

Some proponents of the grounded theory method appear to treat interview and participant observation data as though they mirror informants' realities. Others claim that grounded theory incorporates reflexivity. It is claimed in this article that the principal texts on grounded theory do not attend to the effects of interactions between researchers and participants in interview and participant observation contexts. Descriptions of the effects of interactions on interview data and attention to relationships between interviewers and interviewees are necessary for attending to the rigor of grounded theory findings. Therefore, it is argued that reflexivity and relationality, which are defined as attending to the effects of researcher-participant interactions on the construction of data and to power and trust relationships between researchers and participants, should be incorporated into grounded theory.

Involvement and fragmentation: a study of parental care of hospitalized children in Brazil.

Parental involvement in the care of children who are hospitalized has been encouraged by the government in Brazil, as it has in the United Kingdom (UK). In this paper, key aspects of the UK, North American, and Latin American literature concerning parental participation are discussed, and implications for hospital care of children in Brazil are considered. A study of the division of work between nurses and the mothers (or other relatives) of 10 children hospitalized with chronic illnesses is reported. Data were collected by participant observation of child care in a Brazilian hospital. The results highlight some of the difficulties that arise in the integration of the work of mothers and nurses in hospital care of children and the fragmentation of care into "manual" and "intellectual" work. The results are considered within the theoretical framework of the model of technologic organization of work (Gonçalves, 1979, 1994). Implications for the organization of child care in the hospital are discussed.

Training and education: an analysis of quality assurance in teaching and nursing education.

There is a continuing tension between training and education in vocational higher education courses. The debate in nursing has been heightened by the transfer of courses into higher education and staffing problems in the NHS. Comparisons with other occupations can help prevent introspection in analysis of policy issues in nursing. Teacher training is a particularly useful comparator because it entered higher education before nursing, and teachers have failed to maintain a level of autonomy that nurses would once have envied. This paper compares nursing and teacher training with particular reference to quality assurance. The UK government has adopted a centralized quality assurance and funding system for teacher training. Nursing is included in higher education quality assurance systems but funding is devolved. The tensions between training and education within nursing and teacher training are examined, and implications for the development of nursing considered.

Plasma pharmacokinetics and tissue distribution in CD2F1 mice of Pc4 (NSC 676418), a silicone phthalocyanine photodynamic sensitizing agent.

PURPOSE: Pc4 is a silicone phthalocyanine photosensitizing agent that is entering clinical trials. Studies were undertaken in mice to develop a suitable formulation and analytical methodology for use in pharmacokinetic studies and to define the plasma pharmacokinetics, tissue distribution, and urinary excretion of Pc4 after i.v. delivery. METHODS: An HPLC method suitable for separation and quantification of Pc4 was developed and validated for use in mouse plasma, tissues, and urine. The stability of Pc4 was characterized in a variety of formulations as well as in mouse plasma. Before pursuing pharmacokinetic studies, preliminary toxicity studies were undertaken. These studies utilized Pc4 formulated in diluent 12:0. 154 M NaCl (1:3, v:v). Pharmacokinetic studies involved Pc4 doses of 40 mg/kg, 10 mg/kg and 2 mg/kg administered as i.v. boluses to female, CD2F1 mice. Doses of 40 mg/kg, 10 mg/kg, and 2 mg/kg were studied with drug formulated in diluent 12:0.154 M NaCl (1:3, v:v). Doses of 10 mg/kg and 2 mg/kg were also studied with drug formulated in a vehicle consisting of polyethylene glycol:Tween 80:0. 01 M sodium phosphate buffer, pH 7.0 (40:0.2:59.8, v:v:v). Compartmental and non-compartmental analyses were applied to the plasma concentration-versus-time data. Concentrations of Pc4 were also determined in a variety of tissues, including brain, lung, liver, kidney, skeletal muscle, skin, heart, spleen, and abdominal fat. Urine was collected from animals treated with each of the doses of Pc4 mentioned above, and daily, as well as cumulative drug excretion was calculated until 168 h after treatment. RESULTS: At a dose of 80 mg/kg, two of five male and two of five female mice were dead by 24 h after injection. Pathologic examination revealed gross findings of blue discoloration affecting many tissues, with lungs that were grossly hemorrhagic and very blue-black. Microscopic examination of the lungs revealed mild acute interstitial pneumonia, with perivascular edema and inflammation, and a detectable margination of neutrophils around larger pulmonary blood vessels. Animals sacrificed 14 days after treatment showed mild granulomatous pneumonia, characterized by clusters of multi-nucleated giant cells, with fewer macrophages and neutrophils. The giant cells frequently contained phagocytized particles, which were clear and relatively fusiform. All mice treated with 40 mg/kg or 20 mg/kg survived and returned to pretreatment weight during the 14 days after treatment. Intravenous bolus delivery of Pc4, at a dose of 40 mg/kg, produced "peak" plasma Pc4 concentrations between 7.81 and 8.92 microg/ml in mice killed at 5 min after injection (the earliest time studied after drug delivery). Sequential reduction of the Pc4 dose to 10 mg/kg in diluent 12:0.154 M NaCl (1:3, v:v), 10 mg/kg in polyethylene glycol:Tween 80:sodium phosphate buffer (40:0.2:59.8, v:v:v), 2 mg/kg in diluent 12:0.154 M NaCl (1:3, v:v), and, finally, 2 mg/kg in polyethylene glycol:Tween 80:sodium phosphate buffer (40:0.2:59.8, v:v:v) resulted in "peak" plasma Pc4 concentrations between 2.07 and 3.24, 0.68 and 0.98 microg/ml, and 0.29 and 0.41 microg/ml, respectively. Pc4 persisted in plasma for prolonged periods of time (72-168 h). Non-compartmental analysis of plasma Pc4 concentration-versus-time data showed an increase in area under the plasma Pc4 concentration-versus-time curve (AUC) when the dose of Pc4 increased from 2 mg/kg to 40 mg/kg. Across the 20-fold range of doses studied, total body clearance (CL(tb)) varied from 376 to 1106 ml h(-1) kg(-1). Compartmental modeling of plasma Pc4 concentration versus time data showed the data to be fit best by a two-compartment, open, linear model. Minimal amounts of Pc4 were detected in the urine of mice. After i.v. bolus delivery to mice, Pc4 distributed rapidly to all tissues and persisted in most tissues for the duration of each pharmacokinetic study. Tissue exposure, as measured by AUC, increased in a dose-dependent fash

Tumor-targeted apoptosis by a novel spermine analogue, 1,12-diaziridinyl-4,9-diazadodecane, results in therapeutic efficacy and enhanced radiosensitivity of human prostate cancer.

Interference with polyamine transport and biosynthesis has emerged as an important anticancer strategy involving polyamine analogues and specific inhibitors of key biosynthetic enzymes. Because the prostate gland has a high polyamine content, by using the polyamine transporter for selective uptake into cancer cells, alkylating polyamines are likely to be highly effective against prostatic tumors. We have recently synthesized a novel class of spermine analogues, the lead compound of which has efficacy against human cancer cells (P. S. Callery et al., U. S. patent, 5,612,239, Issued March 17, 1997.). In this study, to investigate the potential therapeutic efficacy of the lead spermine analogue 1,12-diaziridinyl-4, 9-diazadodecane (BIS), against advanced prostate cancer, we examined the in vitro effect and in vivo efficacy of the compound in two androgen-independent human prostate cancer cell lines, PC-3 and DU-145. BIS exhibited a dose-dependent cytotoxic effect against prostate cancer cells via induction of apoptosis. Treatment of cells with BIS (1 microM) for 24 h resulted in a significant induction of apoptosis (24%). Exposure of BIS-treated PC-3 prostate cancer cells to gamma-irradiation resulted in a significant increase in the number of cells undergoing apoptosis and a subsequent decrease in the IC50. Furthermore, BIS treatment led to a significant enhancement of loss of clonogenic survival in irradiated prostate cancer cells (both PC-3 and DU-145). In vivo efficacy trials demonstrated a significant antitumor effect of BIS against both PC-3 and DU-145 tumor xenografts in severe combined immunodeficient mice in a dose-dependent pattern at maximally tolerated doses. Terminal transferase end-labeling analysis indicated that BIS-mediated tumor regression in vivo occurs via induction of apoptosis among prostatic tumor cells. These results suggest that the novel spermine analogue BIS: (a) has a potent antitumor effect against prostatic tumors via induction of apoptosis; and (b) increases the radiosensitivity of human prostate cancer cells by decreasing the apoptotic threshold to radiation. This study may have important clinical implications for the manipulation of this antitumor activity of the polyamine analogue for the optimization of the therapeutic efficacy of radiation in patients with advanced prostate cancer.

Chromatographic methods of analysis of antibiotics in milk.

The widespread use of antibiotics in dairy cattle management may result in the presence of antibiotic residues in milk. While rapid screening tests are commonly used to detect the presence of antibiotics in milk, more accurate chromatographic methods are required by government regulatory agencies to identify and confirm the identity and quantity of antibiotic present. This paper review recent developments in the chromatographic determination of antibiotic residues in milk.

Metabolism of 17-(allylamino)-17-demethoxygeldanamycin (NSC 330507) by murine and human hepatic preparations.

17-(Allylamino)-17-demethoxygeldanamycin (17AAG), a compound that is proposed for clinical development, shares the ability of geldanamycin to bind to heat shock protein 90 and GRP94, thereby depleting cells of p185erbB2, mutant p53, and Raf-1. Urine and plasma from mice treated i.v. with 17AAG contained six materials with absorption spectra similar to that of 17AAG. Therefore, in vitro metabolism of 17AAG by mouse and human hepatic preparations was studied to characterize: (a) the enzymes responsible for 17AAG metabolism; and (b) the structures of the metabolites produced. These materials had retention times on high-performance liquid chromatography of approximately 2, 4, 5, 6, 7, and 9 min. When incubated in an aerobic environment with 17AAG, murine hepatic supernatant (9000 x g) produced each of these compounds; the 4-min metabolite was the major product. This metabolism required an electron donor, and NADPH was favored over NADH. Metabolic activity resided predominantly in the microsomal fraction. Metabolism was decreased by approximately 80% in anaerobic conditions and was essentially ablated by CO. Microsomes prepared from human livers produced essentially the same metabolites as produced by murine hepatic microsomes, but the 2-min metabolite was the major product, and the 4-min metabolite was next largest. There was no metabolism of 17AAG by human liver cytosol. Metabolism of 17AAG by human liver microsomes also required an electron donor, with NADPH being preferred over NADH, was inhibited by approximately 80% under anaerobic conditions, and was essentially ablated by CO. Liquid chromatography/mass spectrometry analysis of human and mouse in vitro reaction mixtures indicated the presence of materials with molecular weights of 545, 601, and 619, compatible with 17-(amino)-17-demethoxygeldanamycin (17AG), an epoxide, and a diol, respectively. The metabolite with retention time of 4 min was identified as 17AG by cochromatography and mass spectral concordance with authentic standard. Human microsomal metabolism of 17AAG was inhibited by ketoconazole, implying 3A4 as the responsible cytochrome P450 isoform. Incubation of 17AAG with cloned CYP3A4 produced metabolites 4 and 6. Incubation of 17AAG with cloned CYP3A4 and cloned microsomal epoxide hydrolase produced metabolites 2 and 4, with greatly decreased amounts of metabolite 6. Incubation of 17AAG with human hepatic microsomes and cyclohexene oxide, a known inhibitor of microsomal epoxide hydrolase, did not affect the production of metabolite 4 but decreased the production of metabolite 2 while increasing the production of metabolite 6. These data imply that metabolite 2 is a diol and metabolite 6 is an epoxide. Mass spectral fragmentation patterns and the fact that 17AG is not metabolized argue for the epoxide and diol being formed on the 17-allylamino portion of 17AAG and not on its ansamycin ring. These data have implications with regard to preclinical toxicology and activity testing of 17AAG as well as its proposed clinical development because: (a) production of 17AG requires concomitant production of acrolein from the cleaved allyl moiety; and (b) 17AG, which was not metabolized by microsomes, has been described as being as active as 17AAG in decreasing cellular p185erbB2.

Aminoalkylaziridines as substrates and inhibitors of lysyl oxidase: specific inactivation of the enzyme by N-(5-aminopentyl)aziridine.

The reaction of lysyl oxidase was assessed with members of a series of aminoalkylaziridines in which the primary amino group and the aziridinyl nitrogen were separated by 3-7 methylene carbons. Among these, N-(5-aminopentyl)aziridine proved to be the poorest substrate by far and to inhibit the enzyme activity. Aminoalkylaziridines with chain lengths shorter or longer than five carbons did not inhibit the enzyme. The resulting inhibition was competitive with productive substrates and became irreversible with time, following pseudo first order kinetics with a KI of 0.22 mM. N-(5-aminopentyl)aziridine appears to act as a bifunctional affinity label covalently interacting with the active site of this enzyme.