Applications of Liquid Chromatography-Tandem Mass Spectrometry in Natural Products Research: Tropane Alkaloids as a Case Study

Although many drugs utilized today are synthetic in origin, natural products still provide a rich source of novel chemical diversity and bioactivity, and can yield promising leads for resistant or emerging diseases. The challenge, however, is twofold: not only must researchers find natural products and elucidate their structures, but they must also identify what is worth isolating and assaying (and what is already known - a process known as dereplication). With the advent of modern analytical instrumentation, the pace of natural product discovery and dereplication has accelerated. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has become an especially valuable technique for identifying and classifying chemical structures. Tropane alkaloids (TAs) are plant-derived compounds of great medicinal and toxicological significance. In this study, we developed an LC-MS/MS-based screening workflow utilizing the multiple MS/MS configurations available on a triple-quadrupole (QQQ) mass spectrometer to annotate and classify TA structures based on their distinct fragmentation patterns. By using a combination of data-dependent (DD) product ion scans, precursor ion scans (PrIS), and neutral loss scans (NLS), we applied this method to TA-rich extracts of the nightshades Datura stramonium and Datura metel. This method is rapid, sensitive, and was successfully employed for both preliminary dereplication of complex TA-containing samples and for the discovery of a novel candidate for isolation, purification (and eventual bioassay).

Multilocus Sequence Typing of Eimeria maxima in Commercial Broiler Flocks

About 35% of all broiler flocks in the United States receive an anticoccidial vaccine, but it is not possible to easily differentiate Eimeria vaccine strains from Eimeria field isolates. Being able to do that would allow using vaccines in a more targeted way. The objective of this study was to collect Eimeria maxima isolates from broiler flocks that received anticoccidial feed additives and flocks that had been vaccinated against coccidia and then test them with a multilocus sequencing typing (MLST) scheme developed for this study. Fecal samples were obtained from commercial broiler flocks in Alabama and Tennessee. Oocyst counts in samples tended to be lower in flocks receiving anticoccidial feed additives and higher in vaccinated flocks. Selected samples were screened for presence of E. maxima by quantitative PCR, and Eimeria spp. composition was investigated by next-generation amplicon sequencing (NGAS) in 37 E. maxima positive samples. Other detected Eimeria spp. besides E. maxima were Eimeria acervulina in 35 samples, Eimeria praecox in 23 samples, Eimeria mitis or Eimeria mivati in 17 samples, and Eimeria necatrix or Eimeria tenella in 10 samples. Six partial E. maxima genes (dnaJ domain containing protein, 70-kDa heat shock protein, prolyl endopeptidase, regulator of chromosome condensation domain containing protein, serine carboxypeptidase, and vacuolar proton-translocating ATPase subunit) of 46 samples were sequenced. The MLST scheme was able to differentiate two vaccines from each other. Three of 17 samples from vaccinated flocks differed from the vaccine used in the flock, while 16 of 29 samples from unvaccinated flocks differed from the vaccine. However, there was also a large number of low-quality, ambiguous chromatograms and negative PCRs for the selected genes. If and when more advanced, possibly next-generation sequencing-based methods will be developed, the genes should be considered as targets.

Patient perceptions of a 1-h art-making experience during blood and marrow transplant treatment

Patients with various forms of cancer receiving blood and marrow transplant (BMT) treatment at an outpatient clinic develop chemotherapy-related symptoms and an increased desire to use complementary and alternative medicine in order to address these symptoms. Art-making offers an inexpensive way to pass time and relieve symptoms during long hours in treatment. Twenty-one BMT patients painted a tile and participated in research. Researchers used semi-structured interviews to understand patients' experiences with art-making. Interviews were recorded, transcribed and coded independently by researchers who met to agree on themes. Ten themes emerged from the data including, meaningful activity (32.2%), expression (18.7%), passing time (13.2%), BMT process (12.1%), social outlet (8.1%), therapy-related symptoms (7.3%), negative aspects of painting (5.9%) and encouragement to paint (2.6%). The results of this study revealed that art-making experience can provide patients a meaningful activity during treatment and an outlet to express their feelings.

Age, breed, sex distribution and nutrition of a population of working farm dogs in New Zealand: results of a cross-sectional study of members of the New Zealand Sheep Dog Trial Association

AIM

To establish baseline information about age, breed, sex distribution and feeding practices for a population of working farm dogs owned by members of the New Zealand Sheep Dog Trial Association (NZSDTA) throughout New Zealand.

METHODS

Questionnaires were sent to members of the NZSDTA in August 2007, requesting information on the size and terrain of the farms where they worked, as well as the breed, weight, age and sex of each working dog they owned, feeding regime employed, diet fed, work levels, and general health of their dogs.

RESULTS

The survey was completed by 542/676 (81%) of the eligible sample population, and provided information on 2,861 dogs, excluding those <1 year old. All of the dog owners surveyed worked on sheep and beef-cattle farms. The median farm size was 440 [Inter-quartile range (IQR) 132-1,200] ha and varied with region. The majority of farms were situated on either hill country (184/542; 34%) or a mixture of hilly and flat terrain (260/542; 48%), and had a median of six (IQR 5-8) working dogs per farm. The median age of dogs was 3.0 (IQR 2.0-6.0) years. Heading dogs were the most common type of working dog (1,510/2,861; 52.8%), followed by Huntaways (1,161/2,861; 40.6%). The gender distribution of all dogs was biased towards males (57%), but this decreased with age. There was a positive association between the number of dogs on a farm and perceived level of tiredness of dogs (p<0.001), but there were no differences in levels of tiredness between farms of different terrain. Most owners (526/542; 97%) fed their dogs once a day. The most common diet fed was a combination of dry food and homekill, which was fed by 328/542 (61%) owners during peak and 313/542 (58%) during off-peak periods of work.

CONCLUSIONS AND CLINICAL RELEVANCE

This study has established baseline information on the age, breed, gender and nutrition of a large population of working farm dogs in New Zealand. Current feeding practices employed by owners include offering a substantial amount of homekill to their animals. Homekill may be deficient or marginal in vitamins and minerals, therefore opportunities could exist to improve the diets and therefore the longevity and performance of these dogs.

A Study of the Surface Texture of Polycrystalline Phosphor Films Using Atomic Force Microscopy

Stimulable phosphor thin films are being investigated for use as optical data storage media. We have successfully applied atomic force microscopy (AFM) to the measurement of the surface texture of these films. Determination of the surface texture of the films is important for evaluating the effect of surface quality on optical scatter. In other thin film material systems it has been found that the surface “bumps” revealed by AFM correspond to grains in the film. This is not the case for the stimulable phosphor films used in our study. We have determined the grain size of our phosphor films by transmission electron microscopy (TEM) and x-ray diffraction (XRD). The grain size from TEM and XRD does not correlate with the size of the AFM surface “bumps.” For example, in two of the five films studied, the XRD derived grain size varies by a factor of two but the size of the surface “bumps” remains the same. We conclude that the texture of the film surface is not directly determined by the grain size of the phosphor material.

Long-term colonization levels of Helicobacter hepaticus in the cecum of hepatitis-prone A/JCr mice are significantly lower than those in hepatitis-resistant C57BL/6 mice

Helicobacter hepaticus infection causes hepatitis in A/JCr mice but mild or no disease in C57BL/6 mice. Colonization of H. hepaticus in the cecum of experimentally infected A/JCr and C57BL/6 mice was quantified by use of real-time polymerase chain reaction (PCR) analysis with primers for the H. hepaticus cdtB gene and mouse 18srRNA. Eight-week-old mice were experimentally (n = 48) or sham (n = 24) infected with H. hepaticus, then were necropsied 6 months after infection. Liver specimens from experimentally infected mice had negative results of PCR analysis for H. hepaticus; thus, real-time quantification was not attempted. Quantitative PCR analysis of H. hepaticus in cecal specimens indicated that C57BL/6 mice were colonized to a greater extent than were A/JCr mice (P < 0.006). Appreciable typhlitis was not observed, but was consistent with that of previous reports; A/JCr mice developed more severe parenchymal necrosis, portal inflammation, and phlebitis in the liver (P < 0.0001), with mild disease observed in infected C57BL/6 mice. Thus, hepatitis in A/JCr mice caused by H. hepaticus infection is associated with significantly lower colonization levels of H. hepaticus in the cecum, compared with those of hepatitis-resistant C57BL/6 mice. Host responses of A/JCr mice that limit cecal colonization with H. hepaticus may have important roles in the pathogenesis of hepatic lesions.

Ketamine sedation for pediatric critical care procedures

OBJECTIVES

To describe our experience using ketamine sedation to facilitate pediatric critical care procedures, and to document the safety profile of ketamine in this setting.

DESIGN

Retrospective consecutive case series.

SETTING

Pediatric intensive care unit of a tertiary children's hospital.

PATIENTS

Children receiving ketamine for procedural sedation over a 5-year period.

INTERVENTIONS

We reviewed patient records to determine indication, dosing, adverse events, inadequate sedation, and recovery time for each sedation.

OUTCOME MEASURES

Descriptive features of sedation including adverse events.

RESULTS

During the study period, children in our pediatric intensive care unit received ketamine at total of 442 times to facilitate a wide variety of critical care procedures, most commonly central line placement, esophagogastroduodenoscopy, and wound debridement. Most study children had substantial underlying illness (ASA > or = 3 in 88%; ASA > or = 4 in 39%). Inadequate sedation was noted in only nine (2%) procedures. Adverse effects included transient laryngospasm (n = 9), transient partial airway obstruction (n = 5), apnea with bradycardia (n = 1), emesis during the procedure (n = 2), emesis during recovery (n = 9), mild recovery agitation (n = 10), moderate-to-severe recovery agitation (n = 1), and excessive salivation (n = 4). There were no adverse outcomes attributable to ketamine.

CONCLUSION

Pediatric intensivists skilled in ketamine administration can safely and effectively administer this drug to facilitate critical care procedures. Despite the ill nature of our patient sample, adverse effects were uncommon.

Native American adolescents' views of fetal alcohol syndrome prevention in schools

Alcohol is the most commonly abused substance among adolescents in the United States. Adolescent females are recognized as one group at risk for giving birth to babies with fetal alcohol syndrome (FAS). Sixth through eighth grade Native Americans were surveyed about their attitudes toward and knowledge of FAS risk factors and prevention strategies. Data revealed that 52% of students drank alcohol prior to the survey. Though sexually active, students lacked knowledge about the relationship between alcohol and FAS. The study revealed 1) limited prevention programs in middle schools and 2) the most influential factor in determining attitudes and decisions about alcohol use was the immediate family. Students felt FAS prevention is an important topic in school health education, noting the important role peers play in teaching and role modeling. Various strategies incorporating music and communication technology such as videotape and computer-assisted interactive tools into prevention materials are discussed.

PCR fidelity of pfu DNA polymerase and other thermostable DNA polymerases

The replication fidelities of Pfu, Taq, Vent, Deep Vent and UlTma DNA polymerases were compared using a PCR-based forward mutation assay. Average error rates (mutation frequency/bp/duplication) increased as follows: Pfu (1.3 x 10(-6)) < Deep Vent (2.7 x 10(-6)) < Vent (2.8 x 10(-6)) < Taq (8.0 x 10(-6)) < < exo- Pfu and UlTma (approximately 5 x 10(-5)). Buffer optimization experiments indicated that Pfu fidelity was highest in the presence of 2-3 mM MgSO4 and 100-300 microM each dNTP and at pH 8.5-9.1. Under these conditions, the error rate of exo- Pfu was approximately 40-fold higher (5 x 10(-5)) than the error rate of Pfu. As the reaction pH was raised from pH 8 to 9, the error rate of Pfu decreased approximately 2-fold, while the error rate of exo- Pfu increased approximately 9-fold. An increase in error rate with pH has also been noted for the exonuclease-deficient DNA polymerases Taq and exo- Klenow, suggesting that the parameters which influence replication error rates may be similar in pol l- and alpha-like polymerases. Finally, the fidelity of 'long PCR' DNA polymerase mixtures was examined. The error rates of a Taq/Pfu DNA polymerase mixture and a Klentaq/Pfu DNA polymerase mixture were found to be less than the error rate of Taq DNA polymerase, but approximately 3-4-fold higher than the error rate of Pfu DNA polymerase.

Site-directed mutagenesis of double-stranded DNA by the polymerase chain reaction

We have developed a facile procedure for rapid PCR-based site-directed mutagenesis of double-stranded DNA. Increasing the initial template concentration and decreasing the PCR cycles to 5-10 allows us to reduce the rate of undesired second-site mutations and dramatically increase the time savings. Following PCR, DpnI treatment is used to select against parental DNA molecules. The DpnI (target sequence 5'-Gm6ATC) is specific for methylated and hemimethylated DNA and is used to digest parental DNA and select for mutation-containing amplified DNA. DNA isolated from almost all common Escherichia coli strains is Dam methylated and therefore susceptible to DpnI digestion. Pfu DNA polymerase is used, prior to intramolecular ligation of the linear template, to remove any bases extended onto the 3' ends of the PCR product by Taq DNA polymerase. The recircularized vector DNA incorporating the desired mutations is transformed into E. coli. This method can be used independently of any host strain and vector.

Hospital utilization for AIDS: are all hospital days necessary?

This study examined hospital utilization and, specifically, unnecessary hospital days for patients with acquired immunodeficiency syndrome (AIDS) in a Midwest regional referral center as of June 1987. In 1990 a follow-up study was conducted to measure changes in length of stay (LOS) and unnecessary days. Results show a mean LOS consistent with other studies and a pattern of unnecessary days comprising 14% to 18% respectively of the mean LOS. Admissions in which the patient died and those considered outliers (LOS greater than 36 days) had a trend toward a higher percentage of unnecessary days. Hospital utilization and unnecessary days for patients with AIDS should be an ongoing quality indicator for hospitals experiencing a high volume of persons with AIDS admissions.

Gene therapy: current status and future directions

Of the many techniques which have been used to introduce new genes into cells, four are of particular interest for gene therapy. Transfection has been most extensively studied and has been used to put new genes into mice and men. Homologous recombination offers the promise of curing certain mutations in situ, but is still largely unexplored. Injection of new genes into the nuclei of single cell embryos has had startling successes in animals, but there are many scientific and ethical issues to be resolved before such an approach can be considered for gene therapy. Retroviral vectors currently offer the most exciting prospect for introducing useful gene sequences into defective cells; however, safety issues and problems of low levels of gene expression are still to be resolved. It appears likely that the bone marrow will be the first target of gene therapy for genetic diseases. The marrow is accessible and contains proliferating stem cells which can transmit the new genes to progeny cells. The possibility of treating enzyme deficiency diseases and hemoglobinopathies by gene transfer is attractive. Experiments in two patients with thalassemia major indicate that it is feasible to introduce new genes into bone marrow cells of man and return the modified cells to hematopoietic sites.

Tc-99m diphosphonate and sulfur colloid uptake by the spleen in sickle disease: interrelationship and clinical correlates: concise communication

To determine the clinical significance of splenic uptake in bone scintigraphy and functional asplenia on the radionuclide liver-spleen image, bone and spleen scintigrams of 38 patients with sickle cell disease were reviewed. Eighteen underwent bone and liver-spleen studies, 15 had only bone images, and five had only liver-spleen studies. Sixteen of 33 who had bone scintigraphy showed splenic uptake, but the frequency of homozygous sickle cell (SS) disease was not greater than heterozygous sickle cell disease (S-hetero) in this group. SS patients with splenic uptake of Tc-99m diphosphonate had significantly fewer painful crises of the abdomen and extremities, and fewer inpatient and outpatient hospital visits than SS patients whose bone imaging did not visualize the spleen. Functional asplenia on liver-spleen images (16 cases) was seen only in SS disease. One SS patient, age 8, still had a spleen capable of phagocytizing colloid.

The major intrinsic protein (MIP) of the bovine lens fiber membrane: characterization and structure based on cDNA cloning

Synthetic oligonucleotide probes have been used to identify two overlapping cDNA clones that represent the entire coding region of the mRNA for the major intrinsic protein (MIP) of bovine lens cell membrane. Hybridization studies indicate that bovine MIP is encoded by a single-copy gene. The cDNA hybridizes to the rat genome, but MIP mRNA is not detected in rat liver. Analysis of the deduced amino acid sequence provides support for the potential role of MIP as a junctional protein. The structure predicted for MIP suggests that it traverses the lipid bilayer six times with both carboxy and amino termini on the cytoplasmic side, and that it has at least one amphiphilic transmembrane segment, as expected if the protein were to participate in the formation of an aqueous channel.

Pilot study on the absolute and relative bioavailability of Synthroid and Levothroid, two brands of sodium levothyroxine

The absolute and relative bioavailability of levothyroxine was determined in young, healthy male subjects after administration of i.v. solution, p.o. solution, or one of two brand-name, commercially available tablets. The mean dose size was about 0.18 mg. Serum concentration-time data were obtained over a period of 50 h. The absolute bioavailabilities of the two tablet preparations were 66% and 72%, respectively.

Coordination environment for the type 3 copper center of tree laccase and CuB of cytochrome c oxidase as determined by electron nuclear double resonance

A new rhombic EPR signal was recently discovered in the partially reduced type 2 copper-depleted Rhus vernicifera laccase (Reinhammar, B. (1983) J. Inorg. Biochem., in press). The signal originates from one of the type 3 Cu(II) ions that becomes EPR-detectable as a result of the selective reduction of the other copper ion in the exchange-coupled Cu(II)-Cu(II) pair. The 14N and 1H and 63,65Cu electron nuclear double resonance (ENDOR) of this uncoupled Cu(II) now have been collected and represent the first ENDOR measurements of a type 3 copper site. The data indicate that the copper is coordinated by at least three nitrogenous ligands, at least one of which is an imidazole. H/D exchange suggests a nearby H2O or OH-, perhaps as a fourth ligand. A similar EPR signal is seen for CuB of reduced cytochrome c oxidase under turnover conditions. The 14N ENDOR, and, therefore, the structure, of this site corresponds extremely closely to that of the laccase type 3 (Cu(II).

Predictive value of intracutaneous xenon clearance for healing of amputation and cutaneous ulcer sites

A previously reported technique for the assessment of skin blood flow in the lower extremities of patients with ischemic lesions was evaluated using intracutaneous xenon clearance. The radioisotope was injected above and below both the ankle and the knee and flow was measured using a gamma camera with a low-energy collimator, 88-keV photopeak, and a 20% window. Healing was more frequent when skin blood flow was equal to or greater than 2.4 ml/min/100 g (38/39 patients) than when flow was less than 2.4 ml/min/100 g (4/7 patients). The authors conclude that this technique can be used to help determine the appropriate site for amputation in lower limb ischemic lesions.

Estimation of clubbing by analysis of shadowgraph

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