Higher cortical and lower subcortical metabolism in detoxified methamphetamine abusers

OBJECTIVE

Methamphetamine has raised concerns because it may be neurotoxic to the human brain. Although prior work has focused primarily on the effects of methamphetamine on dopamine cells, there is evidence that other neuronal types are affected. The authors measured regional brain glucose metabolism, which serves as a marker of brain function, to assess if there is evidence of functional changes in methamphetamine abusers in regions other than those innervated by dopamine cells.

METHOD

Fifteen detoxified methamphetamine abusers and 21 comparison subjects underwent positron emission tomography following administration of [(18)F]fluorodeoxyglucose.

RESULTS

Whole brain metabolism in the methamphetamine abusers was 14% higher than that of comparison subjects; the differences were most accentuated in the parietal cortex (20%). After normalization for whole brain metabolism, methamphetamine abusers exhibited significantly lower metabolism in the thalamus (17% difference) and striatum (where the differences were larger for the caudate [12%] than for the putamen [6%]). Statistical parametric mapping analyses corroborated these findings, revealing higher metabolism in the parietal cortex and lower metabolism in the thalamus and striatum of methamphetamine abusers.

CONCLUSIONS

The fact that the parietal cortex is a region devoid of any significant dopaminergic innervation suggests that the higher metabolism seen in this region in the methamphetamine abusers is the result of methamphetamine effects in circuits other than those modulated by dopamine. In addition, the lower metabolism in the striatum and thalamus (major outputs of dopamine signals into the cortex) is likely to reflect the functional consequence of methamphetamine in dopaminergic circuits. These results provide evidence that, in humans, methamphetamine abuse results in changes in function of dopamine- and nondopamine-innervated brain regions.

Opening of thiiranes: preparation of orthogonal protected 2-thioglyceraldehyde

Treatment of acrolein diethyl acetal sulfide 8 with methanesulfenyl bromide at low temperature results in an efficient thiirane ring opening to a halo disulfide 9. The bromine in this halo disulfide is easily substituted by silver acetate, sodium azide, sodium iodide, and silver nitrate. Treatment of 9 with tetrabutylammonium acetate yields a novel dehydrohalogenation product 12. Silica gel converts bromide 9 into a disulfide-substituted version of acrolein 15. The orthogonal-protected version of 2-thioglyceraldehyde 13 can be deprotected to a useful form of this aldehyde.

Design, synthesis, and biological evaluation of HIV/FIV protease inhibitors incorporating a conformationally constrained macrocycle with a small P3' residue

A series of norstatine-based HIV/FIV protease inhibitors incorporating a 15-membered macrocycle as a mimic of the tripeptide (Ala-Val-Phe), a motif with a small P3' residue elective against the FIV protease and the drug-resistant HIV proteases, has been synthesized. It was found that the macrocycle is important to the overall activity of the inhibitors. Certain inhibitors were developed expressing low nanomolar inhibitory activity against the HIV/FIV proteases and they are also effective against some drug-resistant as well as TL3-resistant HIV proteases.

Enzymes for chemical synthesis

New catalytic synthetic methods in organic chemistry that satisfy increasingly stringent environmental constraints are in great demand by the pharmaceutical and chemical industries. In addition, novel catalytic procedures are necessary to produce the emerging classes of organic compounds that are becoming the targets of molecular and biomedical research. Enzyme-catalysed chemical transformations are now widely recognized as practical alternatives to traditional (non-biological) organic synthesis, and as convenient solutions to certain intractable synthetic problems.

Distinct tumour specificity and IL-7 requirements of CD56(-)and CD56(+) subsets of human gamma delta T cells

gamma delta T cells are believed to recognize tissue injury caused by infections, tumours, as well as chemical and physical agents. The present study was carried out to study the feasibility of the ex vivo expansion of gamma delta T cells from healthy individuals, and to determine their functional capacity against tumours. We selectively expanded the peripheral gamma delta T cells of five donors against a myeloma cell line, XG-7. Under optimal conditions, the resulting bulk cultures comprised about 82% of the gamma delta T cells, more than 90% of which showed the T-cell receptor (TCR)-V gamma 9 delta 2 rearrangement. These gamma delta T-cell cultures exhibited TCR-gamma delta dependent cytotoxicity against different tumour cell lines including Molt-4, BJAB, Epstein-Barr virus (EBV) transformed lymphoid cell lines (LCL), and the nasopharyngeal carcinoma (NPC) cell lines, CNE2 and 915, in addition to the stimulator XG-7. By competitive cytotoxicity assays, the gamma delta T cells demonstrated recognition of at least three distinct target specificities expressed by Molt-4, CNE2 and LCL, respectively, which were related to that expressed by the stimulator XG-7 cells. The recognition of the specificity expressed by XG-7 and Molt-4 was further shown to require the participation of heat shock protein (HSP). The specificity expressed by CNE2 and 915 was preferentially recognized by the CD56 subset of gamma delta T cells, which could be sustained in the presence of interleukin (IL)-7. These results suggested that gamma delta T-cell immunity against tumour cell lines may be acquired in response to other types of tissue injury and, hence, implicates a role for their use in the prevention and treatment of tumours.

Selection of human single chain Fv antibody fragments binding and inhibiting Helicobacter pylori urease

Single chain Fv antibody fragments (scFv) binding to purified Helicobacter pylori urease were selected from a nonimmune human antibody repertoire displayed on filamentous phage. After three rounds of screening on solid phase urease, 44 clones were found to bind the enzyme and four distinct scFv were identified by sequencing their heavy and light chain variable region genes (V(H) and V(L)). Two of the selected human scFv (scFv B4 and scFv D9) inhibited the activity of H. pylori urease with inhibitory constants (K(i)) of 7 and 2 microM, respectively. Their affinity (K(d)) for H. pylori urease as determined by surface plasmon resonance ranged from 17 to 42 nM. Both scFv were able to bind to urease present on the surface of living H. pylori organisms as demonstrated by flow cytometry analysis. The binding sites of scFv B4 and D9 were mapped by the use of two random hexapeptide libraries (X6 and CX6C) displayed on filamentous bacteriophage. The selected peptide sequences were shown to inhibit scFv binding to H. pylori urease and thus could be used in a vaccination strategy as epitopes mimicking (mimotopes) the region of urease recognized by these human scFv antibody fragments.

RNA as a target for small molecules

Proteins are folded to form a small binding site for catalysis or ligand recognition and this small binding site is traditionally the target for drug discovery. An alternative target for potential drug candidates is the translational process, which requires a precise reading of the entire mRNA sequence and, therefore, can be interrupted with small molecules that bind to mRNA sequence-specifically. RNA thus presents itself as a new upstream target for drug discovery because of the critical role it plays in the life of pathogens and in the progression of diseases. In this post-genomic era, RNA is becoming increasingly amenable to small-molecule therapy as greater structural and functional information accumulates with regard to important RNA functional domains. The study of aminoglycoside antibiotics and their binding to 16S ribosomal RNA has been a paradigm for our understanding of the ways in which small molecules can be developed to affect the function of RNA.

Hepatitis B immunization coverage among Vietnamese-American children 3 to 18 years old

OBJECTIVE

Persons with chronic hepatitis B virus (HBV) infection are at increased risk of chronic hepatitis, cirrhosis, and liver cancer. Although HBV infection is relatively uncommon in the United States, the disease is endemic in persons born in Southeast Asia, including Vietnamese-Americans. Current US infant immunization recommendations and state-mandated school-entry programs have left many nontargeted age-cohorts unvaccinated and at risk of infection. To assess the need for catch-up hepatitis B immunizations, this study reports the hepatitis B immunization rates of Vietnamese-American children 3 to 18 years old living in the metropolitan areas of Houston and Dallas, Texas, and the Washington, DC, area.

DESIGN

We conducted 1508 telephone interviews with random samples of Vietnamese households in each of the 3 study sites. We asked for hepatitis B immunization dates for a randomly selected child in each household. Attempts were made to verify immunization dates through direct contact with each child's providers. Low and high estimates of coverage were calculated using reports from providers when reached (n = 720) and for the entire sample (n = 1508).

RESULTS

Rates of having 3 hepatitis B vaccinations ranged from 13.6% (entire sample) to 24.1% (provider reports, Dallas), 10. 3% to 26.4% (Houston), and 18.1% to 37.8% (Washington, DC). Children living in the Texas sites, older children, children whose families had lived in the United States for a longer time, and children whose provider was Vietnamese or who had an institutional provider were less likely to have been immunized. The odds of being immunized were greater, however, for children who had had at least 1 diphtheria, tetanus toxoid, and pertussis shot, and whose parents had heard about HBV infection, and were married.

CONCLUSIONS

The low rates of hepatitis B vaccine coverage among children and adolescents portend a generation which, too old to benefit from infant programs and school entry laws, will grow into adulthood without the protection of immunization. Increased efforts are needed to design successful catch-up campaigns for this population.

Parents' perceptions of chronic illness trajectories

The notion of a small, generic set of chronic illness trajectories that can be independent of specific medical diagnoses, though controversial, has some theoretical, clinical, and qualitative research support. The purpose of this study was to quantitatively describe trajectories among parents of children with a chronic condition. It was hypothesized that factor analysis would confirm 3 trajectories similar to those in the qualitative literature and that parents' perceptions of their child's trajectory would differ significantly from medically based perceptions. A total of 140 parents provided data on their perceptions of the past, present, and future course of the condition of their repeatedly hospitalized child. Fourteen time-related items from the Coping Health Inventory for Parents Questionnaire on Resources and Stress and the Parenting Stress Index were analyzed. Pre- and post-hospitalization factor analyses extracted the same 8 items to construct 3 trajectories: Life Threatening; Declining; and Stable, Optimistic. The views of approximately one third of the parents differed from medically based classifications. Type of nursing care had no bearing on the perceptions of the parents.

Chemo-enzymatic total synthesis of 3-epiaustraline, australine, and 7-epialexine

Sequential enzymatic aldol reaction and bis-reductive amination leads to the total syntheses of tetrahydroxylated pyrrolizidine alkaloids, 3-epiaustaline (14), australine (1), and 7-epialexine (11). This approach allows for their rapid construction without the need for protecting group manipulation of the hydroxyl functionality. In addition, an improved procedure for the asymmetric epoxidation of divinyl carbinol (3) was described, and the product was used in a concise synthesis of the required triol 7 and ent-7.

Bowel dysfunction following spinal cord injury: a description of bowel function in a spinal cord-injured population and comparison with age and gender matched controls

STUDY DESIGN

A controlled, descriptive and comparative, questionnaire based study.

OBJECTIVES

To describe the bowel function of spinal cord injured (SCI) patients and compare this with a general community control group.

SETTING

Christchurch, New Zealand.

METHODOLOGY

A postal questionnaire was sent out to past SCI patients of the Burwood Spinal Injuries Unit, Christchurch, New Zealand, and age/gender matched with controls randomly selected from the electoral roll. Permission was obtained from SCI participants to retrieve data relating to their injury from hospital case notes. The questionnaire detailed general bowel function, influence of bowel problems on everyday life, incidence of incontinence and methods of defecation. A Faecal Incontinence Score was generated according to an established incontinence grading scheme.

RESULTS

Questionnaires were sent out to 1200 SCI patients and 1200 control subjects. Of these, 467 completed questionnaires were returned from SCI patients and age/gender matched from the 668 returned control questionnaires. Mean Faecal Incontinence Score was higher for SCI patients than controls (P<0.0001), and for complete compared with incomplete injury (P=0.0023). Age or time from injury did not affect Faecal Incontinence Score. Incontinence affected quality of life for 62% of SCI patients, compared with 8% of controls. Faecal urgency and time spent at the toilet were also significantly higher for the SCI group (39% of SCI patients use laxatives, compared with 4% of controls (P<0.0001)). Haemorrhoidectomy was more common (P<0.001) in the SCI population (9% vs 1.5%), particularly among those requiring manual evacuations.

CONCLUSION

SCI has a significant effect on bowel function in terms of faecal incontinence, urgency, and toileting methods. This results in a marked impact on quality of life. While bowel function may deteriorate with time, most patients with poor function can be identified early implying a role for early intervention in those with potential bowel problems, such as colostomy or ACE procedure.

Occupational asthma cases notified to OSH from 1996 to 1999

AIMS

To update notifications to the Occupational Safety and Health Service of the Department of Labour (OSH) Notifiable Occupational Disease System (NODS) from June 1996 to the beginning of 1999.

METHODS

All notifications received for non-asbestos related occupational respiratory disease were reviewed to confirm the clinical diagnosis, occupational causation, and to identify the causative agent where possible.

RESULTS

54 cases of asthma were notified, of which 21 (39%) were accepted as being occupationally caused. These cases arose from 'predictable' industries.

CONCLUSIONS

NODS offers sentinel data from interested practitioners and workplaces. Occupational asthma and other occupational respiratory diseases remain poorly notified to this system. NODS confirms the presence of occupational asthma in New Zealand from predictable and preventable causes not dissimilar to other countries. This data collection system needs supplementation by other mechanisms.

Complex carbohydrate synthesis tools for glycobiologists: enzyme-based approach and programmable one-pot strategies

The ultimate goal in complex carbohydrate synthesis is to develop synthetic tools which are simple and easily accessible to glycobiologists. This review will describe methods which have the potential to reach this goal, with particular focus on enzymatic and computer-based one-pot approaches for the preparation of complex carbohydrates and glycoconjugates.

Directed evolution of D-2-keto-3-deoxy-6-phosphogluconate aldolase to new variants for the efficient synthesis of D- and L-sugars

BACKGROUND

Exploitation and improvement of enzymes as catalysts for organic synthesis is of current interest in biocatalysis. A representative enzyme for investigation is the Escherichia coli D-2-keto-3-deoxy-6-phosphogluconate (KDPG) aldolase, which catalyzes the highly specific reversible aldol reaction using the D-configurated KDPG as substrate.

RESULTS

Using in vitro evolution, the aldolase has been converted into aldolases with improved catalytic efficiency, altered substrate specificity and stereoselectivity. In particular, some evolved aldolases capable of accepting both D- and L- glyceraldehyde in the non-phosphorylated form as substrates for reversible aldol reaction have been obtained, providing a new direction to the enzymatic synthesis of both D- and L-sugars.

CONCLUSIONS

This research has demonstrated the effectiveness of using in vitro evolution to rapidly alter the properties of an aldolase to improve its utility in asymmetric synthesis. The evolved aldolases, differing from the native enzyme which is highly phosphate- and D-sugar-dependent, catalyze the efficient synthesis of both D- and L-sugars from non-phosphorylated aldehydes and pyruvate. The principles and strategies described in this study should be applicable to other aldolases to further expand the scope of their synthetic utility.

Overexpression of wild-type RhoA produces growth arrest by disrupting actin cytoskeleton and microtubules

We have investigated the role of Rho GTPase in cell growth by generating stable cells that express the wild-type RhoA (RhoA(wt)) under the control of an inducible promoter. Induction of RhoA(wt) had a biphasic effect on the actin cytoskeleton. At low levels of expression, RhoA(wt) stimulated the assembly of actin stress fibers without affecting cell growth. At high levels, there was a paradoxical disruption of the actin cytoskeleton accompanied by a growth arrest. Cell cycle analysis revealed a dual block at the G(1)/S and G(2)/M checkpoints. The G(1)/S arrest correlated with the accumulation of p21(Cip1), resulting in the inhibition of cdk2 activity, whereas the G(2)/M block correlated with the loss of microtubules. The cyclin B level and the cdc2 kinase activity, however, were increased, suggesting that the progression through mitosis rather than entry into the G(2)/M is defective when RhoA(wt) is overexpressed. Similar cell cycle defects and the loss of microtubules were observed after a cytochalasin D treatment, indicating that the ability of RhoA to regulate the integrity of actin cytoskeleton may be critical for the cell cycle transition through both the G(1)/S and M phase checkpoints.

Chemoenzymatic synthesis of L-galactosylated dimeric sialyl Lewis X structures employing alpha-1,3-fucosyltransferase V

L-Galactosylated dimeric sialyl Lewis X (SLeX) has been prepared employing a combination of chemical and enzymatic synthetic methods. GDP-L-galactose has been chemically synthesised. Enzymatic transfer of L-galactose onto the acceptor (Sia-alpha2,3-Gal-beta1,4-GlcNAc-beta1,3/6)2-Man-alpha1-OMe was achieved using the human alpha-1,3-fucosyltransferase V.

A minimal ankyrin promoter linked to a human gamma-globin gene demonstrates erythroid specific copy number dependent expression with minimal position or enhancer dependence in transgenic mice

In red blood cells ankyrin (ANK-1) provides the primary linkage between the erythrocyte membrane skeleton and the plasma membrane. We have previously demonstrated that a 271-bp 5'-flanking region of the ANK-1 gene has promoter activity in erythroid, but not non-erythroid, cell lines. To determine whether the ankyrin promoter could direct erythroid-specific expression in vivo, we analyzed transgenic mice containing the ankyrin promoter fused to the human (A)gamma-globin gene. Sixteen of 17 lines expressed the transgene in erythroid cells indicating nearly position-independent expression. We also observed a significant correlation between the level of Ank/(A)gamma-globin mRNA and transgene copy number. The level of Ank/(A)gamma mRNA averaged 11% of mouse alpha-globin mRNA per gene copy at all developmental stages. The addition of the HS2 enhancer from the beta-globin locus control region to the Ank/(A)gamma-globin transgene resulted in Ank/(A)gamma-globin mRNA expression in embryonic and fetal erythroid cells in six of eight lines but resulted in absent or dramatically reduced levels of Ank/(A)gamma-globin mRNA in adult erythroid cells in eight of eight transgenic lines. These data indicate that the minimal ankyrin promoter contains all sequences necessary and sufficient for erythroid-specific, copy number-dependent, position-independent expression of the human (A)gamma-globin gene.

Small cell lung carcinoma presenting as acute cardiovascular collapse due to tumour cell embolisation

We present a case of small cell lung carcinoma causing acute cardiovascular collapse due to pulmonary tumour emboli. Although pulmonary tumour emboli may complicate a number of malignancies, this is rarely seen in cases of carcinoma of the bronchus. Patients suffering with pulmonary tumour emboli often have previous symptoms, and show progressive dyspnoea. To our knowledge there have been no reports of tumour emboli presenting acutely without any previous history of symptoms.

Regeneration of PAPS for the enzymatic synthesis of sulfated oligosaccharides

This paper describes the study of 3'-phosphoadenosine-5'-phosphosulfate (PAPS) regeneration from 3'-phosphoadenosine-5'-phosphate (PAP) for use in practical syntheses of carbohydrate sulfates which are catalyzed by sulfotransferases. Among the regeneration systems, the one with recombinant aryl sulfotransferase proved to be the most practical. This regeneration system was coupled with a sulfotransferase-catalyzed reaction, using a recombinant Nod factor sulfotransferase, for the synthesis of various oligosaccharide sulfates that were further glycosylated using glycosyltransferases.

Evaluation of an advanced health assessment course for acute care nurse practitioners

The Acute Care Nurse Practitioner (ACNP) role is being implemented in many centres in Canada. Administrators need to be aware there are very few universities in Canada that prepare ACNPs for advanced health assessment. Therefore, a need may exist for continuing education in the work environment. The ACNPs in London, Ontario recognized such a need, and developed and implemented an Advanced Health Assessment Course using available resources, and administrators supported participation in the course. A pre-post course evaluation based on Bandura's Self-Efficacy theory (1997) was performed. From pre-test to post-test there were significant increases in: (a) the use of health assessement skills; (b) confidence in performing these skills; and (c) confidence in recognizing abnormalities on health assessment. The reasons most often cited for infrequent skill use were "inappropriate to clinical setting" and "used only if problem suspected". The majority of participants agreed that the course met their needs. Implications for practice include administrative support for continuing education at other centres to enhance health assessment skills of ACNPs.