Ostreopsis Schmidt and Coolia Meunier (Dinophyceae, Gonyaulacales) from Cook Islands and Niue (South Pacific Ocean), including description of Ostreopsis tairoto sp. nov.

It is important to decipher the diversity and distribution of benthic dinoflagellates, as there are many morphologically indistinct taxa that differ from one another in production of potent toxins. To date, the genus Ostreopsis comprises twelve described species, of which seven are potentially toxic and produce compounds presenting a threat to human and environmental health. In this study, isolates previously identified as "Ostreopsis sp. 3" were sampled from the area where it was first reported, Rarotonga, Cook Islands, and have been taxonomically and phylogenetically characterised as Ostreopsis tairoto sp. nov. Phylogenetically, the species is closely related to "Ostreopsis sp. 8", O. mascarenensis, "O. sp. 4", O. fattorussoi, O. rhodesiae and O. cf. siamensis. Previously, it was considered a part of the O. cf. ovata complex but can be distinguished from O. cf. ovata based on the small pores identified on this study, and from O. fattorussoi and O. rhodesiae based on relative lengths of the 2' plates. No known palytoxin -like compounds were detected in strains investigated in this study. Strains of O. lenticularis, Coolia malayensis and C. tropicalis were also identified and described. This study advances our knowledge of biogeography, distribution, and toxins of Ostreopsis and Coolia species.

Intra-dialytic intracranial pressure monitoring in a patient with lumbo-peritoneal shunt for idiopathic intracranial hypertension.

We present the case of a 25-year-old female with End-Stage Renal Disease (ESRD) and Idiopathic Intracranial Hypertension (IIH) who developed severe headaches during haemodialysis (HD). The headaches resolved several hours after each HD session. We were able to diagnose dialysis disequilibrium syndrome (DDS) following intracranial pressure (ICP) monitoring and use a novel strategy to treat her symptoms.

Apparent oliguria following urological surgery.

Oliguria is a common feature of acute kidney injury (AKI), but should be interpreted in the context of other biochemical markers when diagnosing and monitoring AKI or considering the need for renal support. We report an unusual case of apparent severe oliguria arising as a result of complex urological pathology and discuss how an understanding of creatinine kinetics raised suspicions of an alternative diagnosis. We discuss the problems caused by an over-reliance on urine output or serum creatinine alone when diagnosing and staging AKI and highlight the need for a more holistic approach.

Calcium sulfates: what is the evidence?

Calcium sulphate has been used extensively as a bioabsorbable bone substitute for 90 years. Its advantages include its low cost, ready availability and unlimited supply, lack of donor site morbidity, use as a delivery vehicle for other compounds (especially antibiotics), inherent osteoconductive properties (based on a structure similar to bone), and its proven safety record. We sought to determine the evidence-based medical studies (prospective and/or randomized clinical trials) that support the use of calcium sulphate as a bioabsorbable bone substitute. At the present time, the majority of reports are basic science investigations, animal studies, and retrospective clinical reviews of varying degrees of quality. Multiple retrospective reviews reveal that calcium sulphate is an effective void-filler in contained bony defects such as metaphyseal voids after impacted fracture reduction (calcaneus, tibial plateau), simple bone cysts, or posttraumatic defects. Three case series examining the use of calcium sulphate in the treatment of bone nonunions revealed a significant failure rate, suggesting that this material, used in isolation, is not optimal to promote union in that setting. A low but consistent complication rate, specifically serous drainage from the wound as the calcium sulphate absorbs, has been reported. This complication is higher when the material is used in higher volumes (greater than 20 mL) or in subcutaneous bones (tibia, ulna). There is some Level I to II evidence (one randomized trial, one case-control study, one prospective cohort study) that antibiotic-impregnated bioabsorbable calcium sulphate has the potential to reduce the number of procedures and surgical morbidity associated with the surgical treatment of chronic osteomyelitis and infected nonunion while maintaining a high rate of infection eradication. Calcium sulphate remains an inexpensive, safe, reliable bone void filler that can also serve as a absorbable delivery vehicle for antibiotics or other compounds. Further high-quality randomized and prospective clinical trials are required to define the role of calcium sulphate in modern orthopaedics.

Theory and practical application of blood-based renal replacement therapy.

The term renal replacement therapy incorporates three modalities that control or correct biochemical and fluid disturbances of renal failure. Peritoneal dialysis and renal transplantation are two forms of renal replacement therapy that are outside the remit of this article. This review focuses upon the third group which are blood-based and involve direct treatment of a patient's blood in a closed, extracorporeal circuit. They provide renal replacement for end-stage renal failure and during periods of severe acute kidney injury, and also for non-renal indications such as the management of drug overdoses. Blood-based renal replacement therapies are often loosely referred to as 'haemodialysis', although this is only one of a range of treatments. This article outlines the theory and practical applications of these treatments.

Catalytic hydrodeoxygenation of methyl-substituted phenols: correlations of kinetic parameters with molecular properties.

The hydrodeoxygenation of methyl-substituted phenols was carried out in a flow microreactor at 300 degrees C and 2.85 MPa hydrogen pressure over a sulfided CoMo/Al(2)O(3) catalyst. The primary reaction products were methyl-substituted benzene, cyclohexene, cyclohexane, and H(2)O. Analysis of the results suggests that two independent reaction paths are operative, one leading to aromatics and the other to partially or completely hydrogenated cyclohexanes. The reaction data were analyzed using Langmuir-Hinshelwood kinetics to extract the values of the reactant-to-catalyst adsorption constant and of the rate constants characterizing the two reaction paths. The adsorption constant was found to be the same for both reactions, suggesting that a single catalytic site center is operative in both reactions. Ab initio electronic structure calculations were used to evaluate the electrostatic potentials and valence orbital ionization potentials for all of the substituted phenol reactants. Correlations were observed between (a) the adsorption constant and the two reaction rate constants measured for various methyl-substitutions and (b) certain moments of the electrostatic potentials and certain orbitals' ionization potentials of the isolated phenol molecules. On the basis of these correlations to intrinsic reactant-molecule properties, a reaction mechanism is proposed for each pathway, and it is suggested that the dependencies of adsorption and reaction rates upon methyl-group substitution are a result of the substituents' effects on the electrostatic potential and orbitals rather than geometric (steric) effects.

Modeling alternative binding registers of a minimal immunogenic peptide on two class II major histocompatibility complex (MHC II) molecules predicts polarized T-cell receptor (TCR) contact positions.

Several major histocompatibility complex class II (MHC II) complexes with known minimal immunogenic peptides have now been solved by X-ray crystallography. Specificity pockets within the MHC II binding groove provide distinct peptide contacts that influence peptide conformation and define the binding register within different allelic MHC II molecules. Altering peptide ligands with respect to the residues that contact the T-cell receptor (TCR) can drastically change the nature of the ensuing immune response. Here, we provide an example of how MHC II (I-A) molecules may indirectly effect TCR contacts with a peptide and drive functionally distinct immune responses. We modeled the same immunogenic 12-amino acid peptide into the binding grooves of two allelic MHC II molecules linked to distinct cytokine responses against the peptide. Surprisingly, the favored conformation of the peptide in each molecule was distinct with respect to the exposure of the N- or C-terminus of the peptide above the MHC II binding groove. T-cell clones derived from each allelic MHC II genotype were found to be allele-restricted with respect to the recognition of these N- vs. C-terminal residues on the bound peptide. Taken together, these data suggest that MHC II alleles may influence T-cell functions by restricting TCR access to specific residues of the I-A-bound peptide. Thus, these data are of significance to diseases that display genetic linkage to specific MHC II alleles, e.g. type 1 diabetes and rheumatoid arthritis.

Comparison of quantum chemical parameters and Hammett constants in correlating pK(a) values of substituted anilines.

Historically, Hammett constants have been extremely effective in describing the influence of substituents on chemical reactivity and other physical and chemical properties, whereas variables derived from quantum chemical calculations have generally been less effective. Taking the experimental pK(a)s of substituted anilines as a representative physicochemical property, five ab initio quantum chemical indices are compared for effectiveness as one-parameter regression descriptors for pK(a). All of the tested descriptors performed well for a set of 19 mono-, 13 di-, and 4 trisubstituted anilines, and two performed somewhat better than the traditional Hammett sigma constants. Among the calculated quantities, the best representation of the aniline pK(a)s is produced by the minimum average local ionization energy on the molecular surface.

Social support for school-aged siblings of children with cancer: a comparison between parent and sibling perceptions.

This descriptive, exploratory study investigated the social support interventions received by school-aged siblings of children with cancer and which of those interventions are perceived as being helpful. A comparison between the siblings' and parents' perceptions was made. The conceptual framework was guided by House's (1981) work on social support, which includes major categories of support variables including emotional, informational, instrumental, and appraisal support. A nonprobability purposive sample consisted of 50 school-aged siblings of children with cancer and their parents. Subjects completed either the sibling or parent version of the Nurse-Sibling Social Support Questionnaire (NSSSQ). Descriptive statistical analyses were performed to examine NSSSQ helpfulness and frequency scores for both siblings and parents. Paired t tests were used to test the difference between the responses given by siblings and by their parents on the NSSSQ helpfulness and frequency scales. Results demonstrated that siblings perceive interventions aimed at providing emotional and instrumental support as the most helpful. Parents perceived interventions aimed at meeting the siblings' need for emotional and informational support the most beneficial. Parents reported that siblings receive emotional, informational, and appraisal support more frequently than siblings did.

Self-concept of siblings of children with cancer.

Childhood cancer can have detrimental effects on the psychosocial well-being of healthy siblings of children with cancer. The limited research done over the past 40 years has identified adjustment difficulties such as poor self-concept, depression, sorrow, anxiety, and feelings of loneliness in children who have a sibling with cancer. To date, clinical research investigating self-concept is scarce as it relates to siblings of children with cancer. The purpose of this study was to examine self-concept in siblings of children with cancer who attended summer camp. A nonprobability purposive sample consisted of 50 school-age siblings of children with cancer. Using the Personal Attribute Inventory for Children (PAIC) to measure children's self-concept, the researcher found that healthy siblings who attended summer camp scored higher on the PAIC than healthy siblings who did not attend camp. This research suggests that social support such as a camp experience may play an important function in coping with having a brother or sister with childhood cancer.

Development of two instruments measuring social support for siblings of children with cancer.

The literature on childhood cancer provides a very limited understanding of healthy siblings' perceptions of supportive interventions during the childhood cancer experience. The purpose of this article is to discuss the development of the Nurse-Sibling Social Support Questionnaire (NSSSQ). Instrument methodology for the study involved item development, face and content validation, and internal consistency reliability as described by Hockenberry-Eaton, Manteuffel, and Bottomley (1997). Item development for the research instrument evolved from an extensive review of the literature and clinical experience of the principal investigator. Content validity of the instrument was accomplished by five experienced pediatric oncology nurses according to the methodology described by Lynn (1986). Using the content validity index, each nurse rated each item as either 4 or 5, indicating 100% agreement among experts that these items measured the concept of social support. Readability for the instrument was determined by using a computerized program. Results showed that readability was concordant with the grade school level for all items. Twenty-five school-age siblings of children with cancer and their mothers were asked to complete the questionnaire. Instrument completion was accomplished in less than 1 hour. The NSSSQ showed high internal consistencies (alpha coefficients >.90). Results indicated that siblings' perceptions of social support differed from those of their mothers. Siblings perceive emotional and instrumental support as greater in importance, whereas mothers perceive emotional and informational support as more beneficial to siblings. Support issues for siblings of children with cancer have been difficult to assess because of the lack of appropriate instruments. This study finding provides exploratory evidence to suggest that the new instrument can help measure siblings' perceptions of social support during the childhood cancer experience.

A concept analysis of social support as experienced by siblings of children with cancer.

Social support is a complex phenomenon. The concept is variably defined by multiple disciplines. This article analyzes the concept of social support by using the methods outlined in the nursing literature. The concept analysis focuses on psychosocial support of siblings of children with cancer. Each step in the concept analysis is presented to show the relevance of the concept with siblings of children with cancer.

Understanding sibling adaptation to childhood cancer.

Clinical research conducted over the past 40 years has described adjustment difficulties healthy siblings face when they have a brother or sister with childhood cancer. Research on healthy siblings of children with pediatric malignancies has advanced over the past few years and has broadened from distinguishing psychosocial problems following the patient's death to identifying stressors during the illness experience. More recent research endeavors have focused on recognizing what behaviors or interventions health care providers understand to be most significant in promoting the patient's, parents', and siblings' coping efforts with childhood cancer and its treatment. In addition, descriptive research is exploring interventions used by pediatric oncology health care providers to render social support to siblings of children with cancer (Murray, 1999). Despite the growing body of literature on sibling adaptation to childhood cancer, an understanding of this experience from a developmental perspective is lacking. This lack of theoretical understanding may contribute to inadequate care of siblings of children with cancer. Understanding the meaning cancer has for well siblings is critical. This article discusses the theoretical framework of child development in relation to understanding sibling adaptation to the childhood cancer experience.

Conducting psychosocial research with children and adolescents: a developmental perspective.

In the past 10 years, childhood has become a focal point of concern. Children are viewed as symbolizing an investment in the future of societies around the world. In the past, knowledge about children's views was realized through objective measures or from representative accounts by adults (e.g., parents and teachers) who were thought to know the child best. Current research suggests that most adult representations and interpretations are only attempts to describe something that more or less represents the child's world. The literature suggests that in the past, children have been perceived mainly as objects rather than subjects of research interest. This perhaps reflects the viewpoint held by many that children are unable to comprehend and describe their world and life experiences because of developmental immaturity and/or that there are intrinsic difficulties in researching children. The purpose of this article is to describe how a child's developmental level affects the research process. Specifically discussed are developmental differences in responses to research including psychosocial research methods, assent, and consent with children.

Attachment theory and adjustment difficulties in siblings of children with cancer.

The demands of the childhood cancer experience on children and their parents has been investigated for a number of years. Despite this research, very little emphasis has been placed on well siblings. In the health care profession today, there is a growing perception that the psychosocial needs of the healthy siblings of children with cancer are less sufficiently met than those of other members of the family system. Previous research proposes that well siblings are especially susceptible to a number of adjustment difficulties (such as depression, anger, anxiety, feelings of guilt, and social isolation) (Murray, 1999). Given these findings, the question arises as to whether the adjustment difficulties seen in siblings are a result of the loss of, or separation from, the attachment figure--the mother who is busy caring for the child with cancer. The purpose of this article is to use attachment theory as a conceptual framework to try to understand the effects of the childhood cancer experience on siblings. Recent findings regarding siblings of children with cancer and some speculations regarding clinical implications are provided.

The role of resistance testing in clinical trial design and product labelling: a regulatory perspective.

Assays that attempt to characterize HIV susceptibility or resistance are among the latest technologies that are likely to impact HIV clinical trial design, antiretroviral drug development and patient management. However, at present the Food and Drug Administration (FDA) have yet to approve any phenotypic or genotypic HIV resistance assay and the role of resistance testing in clinical management of patients and in drug development is ill defined. In November 1999, the Division of Antiviral Drug Products at the FDA convened a meeting of its advisory committee to consider the available information about HIV resistance testing, and to generate some recommendations about how these assays could be utilized in antiretroviral drug development. In addition, the committee was presented with several hypothetical regulatory scenarios in order to illustrate how HIV resistance testing might be incorporated in antiretroviral drug development and drug labelling. In this article, we discuss the regulatory history of resistance testing in antimicrobial drug development, the current use of resistance testing for antiretrovirals, as well as a summary of the hypothetical scenarios that were presented to the committee and the discussion of the committee members regarding those scenarios.

Detection and Partial Characterization of Tenuiviruses from Black Spruce.

Filamentous viral ribonucleoproteins (RNPs) 12 to 16 nm in diameter and 100 to 1,260 nm in length, and characteristic of the genus Tenuivirus, were detected by transmission electron microscopy in purified extracts of needles collected from two mature, asymptomatic black spruce (Picea mariana) trees in New York, but not in extracts of needles from nursery seedlings. Purified RNPs from one tree had a buoyant density in CsCl = 1.39 g/cm3 and an A 260/280 = 1.436. Four ssRNA segments of 1.3, 2.1, 2.3, and 3.5 kb, but not the 8- to 9-kb fragment characteristic of most tenuiviruses, were detected in purified RNA extracts. Amplification products of the expected size were observed when RNA extracts from the two spruce trees and Maize stripe tenuivirus (MStpV), but not from tobacco, Chenopodium quinoa, or spruce seedlings were subjected to reverse transcription-polymerase chain reaction (RT-PCR) using primers to the p3 open reading frame (ORF) of MStpV vRNA 3. However, only MStpV amplified when primers to the nucleocapsid ORF (pc3 ORF on vcRNA 3) were used. Similarly, only MStpV amplified by immunocapture polymerase chain reaction (PCR) using antiserum to MStpV and primers to the p3 ORF. Sequence comparisons suggest that two distinct tenuiviruses occur in black spruce, one more closely related to MStpV than the other. One of these tenuiviruses was detected in one of 10 additional black spruce trees tested, but not in trees of six other coniferous species sampled in the Adirondack Mountains of New York.