The development of an FIA-CD strategy for screening sulfated polysaccharides using antimalarial drugs and related species as probes.

Heterogeneous sulfated polysaccharides have attracted significant attention in light of their various biological activities. However, recent events involving heparin have dramatically illustrated that several analytical challenges exist in accounting for such species. In this case, tainted heparin was associated with acute reactions that lead to numerous deaths. Researchers were forced to use time-consuming, sophisticated techniques (e.g., enzymatic digestion, NMR, CE, HPLC, MS, etc.) to identify the cause of these adverse effects. Extensive investigations ultimately showed oversulfated chondroitin sulfate, a semi-synthetic sulfated polysaccharide, to be present in the contaminated samples. These events highlighted the need for a new generation of screening techniques. In this work, we report the development of a screening strategy that exploits unique circular dichroism features observed as a function of association between investigated polymers and judiciously selected probe molecules (i.e., chloroquine, N1-(7-chloro-4-quinolinyl)-N3-methyl-1,3-propanediamine, quinacrine, and N2-9-acridinyl-N1,N1-dimethyl-1,2-ethanediamine). Application of obtained spectropolarimetry results to a flow injection analysis circular dichroism platform allowed for the establishment of linear polysaccharide response curves for dextran sulfate, heparin, and oversulfated chondroitin sulfate in the low micromolar range. Lastly, through additional work with heparin, the proposed method was shown to be capable of rapidly screening sulfated polysaccharide samples for closely related impurities.

Rapid determination of surfactant critical micelle concentrations using pressure-driven flow with capillary electrophoresis instrumentation.

This work demonstrates a novel, convenient utilization of capillary electrophoresis (CE) instrumentation for the determination of critical micelle concentrations (CMCs). Solution viscosity differences across a range of surfactant concentrations were monitored by hydrodynamically forcing an analyte towards the detector. Upon reaching the surfactant's CMC value, migration times were observed to change drastically. CMC values for four commonly employed anionic surfactants were determined-sodium dodecyl sulfate: 8.1mM; sodium caprylate: 300 mM; sodium decanoate: 86 mM; sodium laurate: 30 mM; and found to be in excellent agreement with values previously reported in the literature. The technique was then applied to the less well-characterized nonionic surfactants poly(oxyethylene) 8 myristyl ether (CMC approximately 9 M), poly(oxyethylene) 8 decyl ether (CMC approximately 0.95 mM) and poly(oxyethylene) 4 lauryl ether.

Heparin-induced circular dichroism of chloroquine.

Circular dichroism (CD) and UV/Visible absorption (UV/Vis) spectroscopy techniques were used to investigate the interaction between heparin and chloroquine, an antimalarial drug that has shown potential as an anti-prion agent. CD spectra of rac-chloroquine upon addition of heparin provide evidence of glycosaminoglycan (GAG) binding, support recent findings suggesting that interactions between heparin and antimalarial drugs are largely due to electrostatic interactions, and represent the first reported GAG-induced CD signal of a bicyclic, aromatic compound. The association constant ( approximately 10(3)M(-1)) between chloroquine and heparin was calculated from a UV titration curve and provided additional insight into the nature of the association between these two compounds.

Bardet-Biedl syndrome: a molecular and phenotypic study of 18 families.

The autosomal recessive disorder Bardet-Biedl syndrome is characterised by retinal degeneration, polydactyly, obesity, mental retardation, hypogenitalism, renal dysplasia, and short stature. It is heterogeneous with at least four gene loci (BBS1-4) having been mapped to date. We have studied 18 multiply affected families noting the presence of both major and minor manifestations. Using a fluorescently based PCR technique, we genotyped each family member and assigned linkage to one of the four loci. Given this degree of heterogeneity we hoped to find phenotypic differences between linkage categories. We found 44% of families linked to 11q13 (BBS1) and 17% linked to 16q21 (BBS2). Only one family was linked to 15q22 (BBS4) and none to 3p12. We conclude that BBS1 is the major locus among white Bardet-Biedl patients and that BBS3 is extremely rare. Only subtle phenotypic differences were observed, the most striking of which was a finding of taller affected offspring compared with their parents in the BBS1 category. Affected subjects in the BBS2 and 4 groups were significantly shorter than their parents. Twenty eight percent of pedigrees did not show linkage to any known locus, evidence for at least a fifth gene. We conclude that the different genes responsible for Bardet-Biedl syndrome may influence growth characteristics such as height.

Childhood asthma and exposure to indoor allergens: low mite levels are associated with sensitivity.

The prevalence and level of sensitivity to indoor allergens were studied in relation to current exposure at home in 124 children with perennial asthma living in three climatic zones of Sweden. The house dust mite (HDM) allergen levels were higher in the South than in the North (p < 0.001), while cat and dog allergen levels tended to be higher in the North than the South (n.s.). Thirty-four percent of the children were sensitive to the HDM Dermatophagoides pteronyssinus, as determined by IgE antibodies in vitro, 27% were sensitive to D. farinae, 57% to cat and 55% to dog. Sensitivity to HDM was significantly more prevalent in Southern, than in Central and Northern Sweden (p = 0.001) where the children were more often sensitive to pets (cat p = 0.005, dog p = 0.002). A significant association between the concentration of Der p I and Der fI in the house dust and both the prevalence of sensitivity to HDM and the IgE antibody levels against mites was found even at concentrations well below the commonly suggested risk level for sensitisation of 2 micrograms/g dust. No relationship was found between pet allergen concentration in the home dust and sensitivity to pets, possibly because of exposure outside home, e.g. in schools and meeting places for leisure activities. Similarly, there was no consistent association between the level of mite or pet allergen exposure at home and asthma severity as judged by symptom and medication score. The study indicates that there is no threshold value for sensitisation to mite allergens in asthmatic children, and therefore, dust allergen levels at home should be kept as low as possible in homes of children at risk for asthma.

Electrochemical detection of peptides.

A general method of wide applicability for the determination of peptides is described. Peptides longer than dipeptides react in the classical biuret reaction with Cu(II) to yield electroactive Cu(II)-peptide complexes that can be oxidized to the corresponding Cu(III) complexes. This allows the sensitive electrochemical detection of peptides following their separation by reversed-phase liquid chromatography. The reaction chemistry, which is reversible, allows for the determination of peptides that lack an electroactive group or a primary amine. Selectivity for a model peptide is 10(3)-10(4) over nonelectroactive amino acids.

Therapeutic drug analysis and the clinical laboratory.

This paper presents a general review of the rapidly expanding area of therapeutic drug monitoring and discusses the reasons for measuring serum drug levels. The assay methods commonly used in the clinical laboratory--including gas chromatography, high pressure liquid chromatography, radioimmunoassay, enzyme multiplied immunoassay and fluorescent immunoassay--are discussed. Unique characteristics of the commonly monitored drugs are presented.

Alkylamine salts and amides: in vitro inhibition of S mutans 6715.

Our studies with the salts and amides of alkylamines have shown that the undecylenate salts have significant in vitro activity against S mutans No 6715, suggesting that these agents are worthy of additional evaluation. The attempt to increase activity by combining undecylenic acid with the alkylamines was not successful; however, better attachment to tooth surfaces and/or retention during washing did occur. Our results suggest that the free amino group of alkylamines and the free acid group of undecylenic acid are required for these two classes of agents to demonstrate antibacterial activity.

Synthesis and antimalarial activity of dibenz[c, e]azepine derivatives.

A series of 6-alkyl-2,10-bis(trifluoromethyl)-5H-dibenz-[c,e]azepines were synthesized via a condensation reaction between 5,5'-bis(trifluoromethyl)-2,2'-diformylbiphenyl and the appropriate amine. These compounds were screened for antimalarial activity and were found to be inactive.

A physiochemical approach to the study of amines as antiplaque agents.

Alkyl and aromatic amines were evaluated for inhibitory activity against S mutans 6715. Only the alkylamines were active and this may be due to their greater basicity. The agents that showed good activity were decylamine, dodecylamine, tetradecylamine, and hexadecylamine. In addition to the free bases, the hydrochloride and hydrofluoride salts were also tested for inhibitory activity and the same four agents were shown to be most active. These agents appear to hold good promise as antiplaque agents against S mutans 6715, therefore, further in vitro studies against other plaque-forming bacteria and toxicological and clinical evaluation seems to be warranted to determine the best clinical agent.

Delayed severe extrapyramidal disturbance following frequent depot phenothiazine administration.

The authors report the occurrence of a sever striopallidal disorder in a schizophrenic patient one week after he received fluphenazine enanthate injections on an every-other-day schedule. In view of current interest in depot psychopharmaceuticals, they recommend that careful attention be given to dosage and administration schedules and to the possibility of delayed pseudoparkinsonian symptoms. Emergency room physicians should be alerted to the possible side effects of such drugs.

Painful ophthalmoplegia: report of a case with cerebral involvement and psychiatric complications.

The diagnosis of Tolosa-Hunt syndrome should be suspected in the presence of recurrent "painful ophthalmoplegia." The most useful tests are the rapid (within 48 hours) response to steroids and positive findings on orbital venography. It should be emphasized that Tolosa-Hunt's syndrome may not be a "pure syndrome." Perhaps it is only an occasional presentation of another rather poorly understood syndrome, that of "recurrent cranial neuropathies." The present patient had at least three episodes of painful ophthalmoplegia prior to this hospitalization. During the last hospitalization, he presented with painful ophthalmoplegia, showed a rapid response to steroids, had narrowing of the carotid artery on arteriogram and an abnormal orbital venogram. However, during his hospitalization he developed involvement of cranial nerves II, III, V, VI and VII, papilledema, pyramidal tract signs and severe psychiatric disturbances, all of which remitted. This, coupled with the abnormal pneumoencephalogram and electroencephalogram and organicity on psychological testing, suggests cerebral involvement in our case.