Separation of enantiomers: needs, challenges, perspectives.

Chiral drugs, agrochemicals, food additives and fragrances represent classes of compounds with high economic and scientific potential. First the present implications of their chiral nature and necessity of separating enantiomers are summarised in this article. In the following a brief overview of the actual approaches to perform enantioseparations at analytical and preparative scale is given. Challenging aspects of these strategies, such as problems associated with data management, choice of suitable chiral selectors for given enantioseparations and enhanced understanding of the underlying chiral recognition principles, are discussed. Alternatives capable of meeting the requirements of industrial processes, in terms of productivity, cost-effectiveness and environmental issues (e.g., enantioselective membranes) are critically reviewed. The impact of combinatorial methodologies on faster and more effective development and optimisation of novel chiral selectors is outlined. Finally, the merits and limitations of most recent trends in discrimination of enantiomers, including advances in the fields of sensors, microanalysis systems, chiroptical methods and chemical force microscopy are evaluated.

Enantioseparation of various amino acid derivatives on a quinine based chiral anion-exchange selector at variable temperature conditions. Influence of structural parameters of the analytes on the apparent retention and enantioseparation characteristics.

The influence of temperature on the performance of an enantioselective anion-exchange type chiral selector (SO) was systematically investigated. The resolution of the enantiomers of 23 N-acylated amino acids (selectands, SAs) on a covalently immobilized quinine tert.-butylcarbamate chiral stationary phase (CSP) was studied under linear chromatographic conditions over a temperature range of 0-85 degrees C with hydro-organic buffers (pHa 6.0) as mobile phases. The apparent enantioseparation factors increased considerably at low column temperatures, indicating that enthalpic contributions are the dominating thermodynamic driving force for chiral recognition for all investigated SAs. Retention factors gave non-linear van't Hoff plots, while the corresponding apparent enantioseparation factors showed linear van't Hoff behavior. Correlations between magnitude and sign of the relative thermodynamic parameters of enantioselective adsorption (deltadeltaG, deltadeltaH and deltadeltaS) and specific structural features of the analytes, i.e., steric and electronic nature of the various side chains and the N-acyl groups, are discussed with the aim to rationalize their possible contributions to the overall chiral recognition.

Observation of a polar bear with rabies.

On 1 November 1989 the first confirmed case of rabies in a polar bear (Ursus maritimus) was encountered by Inuit hunters in the vicinity of Cape Kendall, Southampton Island, Northwest Territories (Canada). The adult male polar bear had posterior paralysis. Rabies was detected by mouse inoculation and a positive immunoperoxidase reaction on spinal cord and Gasserian ganglion from the bear. Histologic lesions in the lumbar region of the spinal cord were consistent with the posterior paralysis. The impact of rabies on the population dynamics of polar bears probably is minimal. Rabies in polar bears constitutes a potential health hazard for polar bear hunters.

Examining the feasibility of hospital-based intervention for mothers and their drug-exposed neonates.

PURPOSE: To examine the effects of an educational intervention that teaches specialized newborn, care to substance-abusing mothers. METHOD: A quasi-experimental design included an educational intervention for a group of mothers whose babies had positive meconium stains for cocaine. Outcomes were to be assessed by the Brazelton Neonatal Behavioral Assessment Scale and Nursing Child Assessment Feeding Scale. FINDINGS: Due to a change in the hospital's discharge policy resulting in early discharge, recruitment difficulties occurred. CONCLUSION: The ramifications of this change in discharge policy are discussed.

Easing the wait: development of a pager program for families.

Waiting is inevitable for patients and families seeking health care services. Anxiety, frustration, and stress are exacerbated. A pager program, where pagers are loaned free of charge to families, uses a family-centered approach to counteract the aggravation of waiting. Patients and families can leave the hospital room or clinic setting and then be paged to return as needed. In any clinical setting, having choices and control will enhance coping and satisfaction for both patients and families.

The behavioral flow sheet. A tool for the primary care provider.

Behavioral flow sheets are tools that can be used outside the domain of mental health. For the knowledgeable health care provider in any setting, they render a cost-effective, noninvasive mechanism for diagnosis and management of a variety of patient problems of organic as well as behavioral natures. Though there exists an assortment of standardized formats, flow-sheet design can be tailored to address the unique circumstances of each patient. They provide an avenue for actively involving patients and families in problem assessment as well as in the planning and evaluation of treatment regimens. In addition, flow sheets provide a feedback mechanism that can enhance patient/family self-esteem and increase the likelihood of adherence to treatment recommendations. There is both an art and a science to their design and use, but the skills involved are readily acquired by any interested practitioner. The conscientious professional will become acquainted with the potential pitfalls and thus avoid irresponsible or unethical application. The authors provide guidelines for developing and implementing flow sheets and illustrate their value through the sharing of several clinical vignettes.

IgA NMDA receptor antibodies are markers of synaptic immunity in slow cognitive impairment.

OBJECTIVE: To report that antibodies to synaptic proteins may occur in association with slow, progressive cognitive decline. METHODS: A total of 24 patients with progressive cognitive dysfunction of unclear etiology were examined for onconeuronal and synaptic receptor antibodies. The effect of serum was examined in cultures of dissociated mouse hippocampal neurons. RESULTS: Seven patients had immunoglobulin A (IgA), but no immunoglobulin G (IgG), antibodies against NMDA receptor (NMDAR). Anti-NMDAR IgA positive patients' serum, but not serum from control individuals, caused dramatic decrease of the levels of NMDAR and other synaptic proteins in neurons, along with prominent changes in NMDAR-mediated currents. These effects correlated with the titer of IgA NMDAR antibodies and were reversed after removing patients' serum from the culture media. When available, comprehensive clinical assessment and brain metabolic imaging showed neurologic improvement after immunotherapy. CONCLUSIONS: A subset of patients with slowly progressive cognitive impairment has an underlying synaptic autoimmunity that decreases the density of NMDAR and other synaptic proteins, and alters synaptic currents. This autoimmunity can be demonstrated examining patients' serum and CSF for NMDAR IgA antibodies, identifying possible candidates for immunotherapy.