Primary care for adults with Down syndrome: adherence to preventive healthcare recommendations.

BACKGROUND: Due to significant medical improvements, persons with Down syndrome now live well into adulthood. Consequently, primary care for adults with Down syndrome needs to incorporate routine care with screening for condition-specific comorbidities. This study seeks to evaluate the adherence of primary care physicians to age- and condition-specific preventive care in a cohort of adults with Down syndrome. METHODS: In this retrospective observational cohort study, preventive screening was evaluated in patients with Down syndrome aged 18-45 years who received primary care in an academic medical centre from 2000 to 2008. Comparisons were made based on the field of patients' primary care providers (Family or Internal Medicine). RESULTS: This cohort included 62 patients, median index age = 33 years. Forty per cent of patients received primary care by Family Physicians, with 60% seen by Internal Medicine practices. Patient demographics, comorbidities and overall screening patterns were similar between provider groups. Despite near universal screening for obesity and hypothyroidism, adherence to preventive care recommendations was otherwise inconsistent. Screening was 'moderate' (50-80%) for cardiac anomalies, reproductive health, dentition, and the combined measure of behaviour, psychological, or memory abnormalities. Less than 50% of patients were evaluated for obstructive sleep apnea, atlanto-axial instability, hearing loss or vision loss. CONCLUSIONS: We observed inconsistent preventive care in adults with Down syndrome over this 8.5-year study. This is concerning, given that the adverse effects of many of these conditions can be ameliorated if discovered in a timely fashion. Further studies must evaluate the implications of screening practices and more timely identification of comorbidities on clinical outcomes.

Adaptive responses in eye-head-hand coordination following exposures to a virtual environment as a possible space flight analog.

Virtual reality environments (VRs) offer unique training opportunities, particularly for training astronauts and preadapting them to the novel sensory conditions of microgravity. The purpose of the current research was to compare disturbances in eye-head-hand (EHH) sensorimotor coordination produced by repeated exposures to VR systems. In general, we observed significant increases in position errors for both horizontal and vertical targets. The largest decrements were observed immediately following exposure to VR and showed general recovery within 6 hours across each test session, but not across days. Subjects generally showed faster reaction times across days. These findings provide some direction for developing training schedules for VR users that facilitate adaptation and support the idea that VRs may serve as an analog for sensorimotor effects of spaceflight.

Evaluating health impact assessment.

Health impact assessment (HIA) is a developing approach that assesses the health impacts of a proposal on a population, and produces a practical set of recommendations to inform the decision-making process of the proposal. The purpose is to influence decision makers to increase positive health impacts of a proposal and decrease negative impacts. Most work within the HIA field to date has focused on methodological development and actually carrying out HIAs. Little attention has been paid to the formal evaluation of the HIA approach and whether or not HIA works (if and how the HIA approach informs the decision-making process and, in particular, if it contributes to improving health and reducing inequalities). With the drive towards evidence-informed policy, HIA also needs to show whether it adds value to the decision-making process, given the significant resources often involved in carrying out an HIA. A suggested approach to evaluating HIAs is presented, as well as its relationship with monitoring, drawing on the significant public health evaluation literature that already exists. Methodologies appropriate for use, and examples of indicators suitable for HIA evaluation, are provided. We suggest that typical HIA evaluations should focus on the process of the HIA and the impact that it has on the decision-making process, rather than attempting to evaluate long-term health outcomes or whether predicted impacts actually occurred.

Work attitudes, employment barriers, and mental health symptoms in a sample of rural welfare recipients.

Most of the extant research on welfare reform has neglected to consider the experiences of families in rural settings. Fifty women receiving welfare for their dependent children in a rural community were interviewed about their work experiences and aspirations, barriers to employment and service use, as well as mental health and social support. The findings indicate that the majority of participants were connected to the labor force and expressed positive attitudes about work. Barriers to employment (lack of available jobs, child care) and service use (transportation, inconvenient office hours) were endorsed. Perceived social support was negatively related to depression symptoms and positively related to self-efficacy and self-esteem. The importance of understanding the life experiences of welfare recipients in different contexts is discussed.

Application of high-density optical microwell arrays in a live-cell biosensing system.

In this paper, we use optical imaging fibers to fabricate a chemical and biochemical sensor that utilizes the ability of living cells to respond to biologically significant compounds. The sensor is created by randomly dispersing single NIH 3T3 mouse fibroblast cells into an optically addressable fiber-optic microwell array such that each microwell accommodates a single cell. The cells are encoded to identify their location within the array and to correlate changes or manipulations in the local environment to responses of specific cell types. The entire array can be simultaneously measured, yielding a rapid, repetitive, and high-density analysis method.

A far-field-viewing sensor for making analytical measurements in remote locations.

We demonstrate a far-field-viewing GRINscope sensor for making analytical measurements in remote locations. The GRINscope was fabricated by permanently affixing a micro-Gradient index (GRIN) lens on the distal face of a 350-micron-diameter optical imaging fiber. The GRINscope can obtain both chemical and visual information. In one application, a thin, pH-sensitive polymer layer was immobilized on the distal end of the GRINscope. The ability of the GRINscope to visually image its far-field surroundings and concurrently detect pH changes in a flowing stream was demonstrated. In a different application, the GRINscope was used to image pH- and O2-sensitive particles on a remote substrate and simultaneously measure their fluorescence intensity in response to pH or pO2 changes.

Randomly ordered addressable high-density optical sensor arrays.

Array-based sensors provide an architecture for multianalyte sensing. In this paper, we report a new approach for array fabrication. Sensors are made by immobilizing different reactive chemistries on the surfaces of microspheres. Sensor arrays are prepared by randomly distributing a mixture of microsphere sensors on an optical substrate containing thousands of micrometer-scale wells. The sensors occupy a different location from array to array; thus the identity of each sensor is ascertained and registered on the detector using encoding schemes, rather than by a predetermined location in the array. The approach thereby shifts the demand from fabrication to signal processing. The availability of commercial image analysis software makes such a shift both cost-effective and time efficient.

Characterization of monoclonal antibody glycosylation: comparison of expression systems and identification of terminal alpha-linked galactose.

CAMPATH-1H is a recombinant humanized murine monoclonal immunoglobulin (IgG1) which recognizes the CDw52 antigen of human lymphocytes, and has been the subject of clinical trials for the treatment of non-Hodgkin's lymphoma and rheumatoid arthritis. Peptide mapping by liquid chromatography-mass spectrometry was used to confirm the predicted amino acid sequences and profile glycosylation for two CAMPATH isotypes expressed in a murine myeloma cell line (NS0) and a single isotype expressed in both Chinese hamster ovary (CHO) and NS0 lines. The three major glycoforms identified in CAMPATH are fucosylated biantennary structures, containing zero, one, or two galactose residues. Glycosylation of the IgG1 form of CAMPATH expressed in CHO cells is consistent with normal human IgG. However, IgG1 and IgG4 expressed in NS0 cells include two potentially immunogenic glycoforms which contain either one or two nonreducing terminal alpha-linked galactose residues. Oligosaccharide structures were characterized by a combination of tandem mass spectrometry, methylation analysis, and exoglycosidase digestion. The strategy used here is designed to be widely applicable to recombinant glycoproteins.

Synthesis, structure and stability of novel dimeric peptide-disulfides.

Oxidation of nonapeptide dithiol (2) with K3Fe(CN)6 leads to either monomeric disulfide (4) or antiparallel and parallel dimeric disulfides (3a and 3b) depending upon reaction conditions. When exposed to small amounts of thiols or cyanide in aqueous solution, these three species interconvert to an equilibrium mixture of 2:1:8 (3a:3b:4).

In vitro metabolism of a potent HIV-protease inhibitor (141W94) using rat, monkey and human liver S9.

Compound 141W94 (Vertex VX478) (3S)-tetrahydro-3-furyl N-[((S,2R)-3-(4-amino-N-isobutylbenzenesulfonamido)-1-benzyl- 2-hydroxypropyl] carbamate, is a potent HIV-protease inhibitor and is currently undergoing clinical trials. The purpose of this study was the rapid identification of the phase I and II in vitro metabolite of 141W94 using mass spectrometry. Four different sources of liver S9 fractions were used for studying comparative in vitro metabolism of 141W94. They were obtained from Arochlor-induced rat, normal (untreated) rat, cynomolgus monkey and human livers. Selected incubations were supplemented with uridine diphosphate glucuronic acid and the reduced form of glutathione. The predominant species seen in the incubation mixture was the parent compound 141W94. Metabolites arising from ring opening to form the diol and carboxylic acid and oxidation of the tetrahydrofurran ring (formation of dihydrofuran) were identified. In addition, of the two monohydroxylated products identified, one resulted from hydroxylation on the aniline ring and the other from hydroxylation at the benzylic position. Two different glucuronides were also observed. Comparing the three species, very little metabolism was seen in the normal (non-induced) rat. The metabolic profile and extent of metabolism with induced rat, monkey and human S9 was similar. Induced rat S9 incubation showed the formation of two unique metabolites that were not seen in non-induced rat, monkey and human S9 fractions. They were the monohydroxylated glucuronide and a carbamate cleavage product. The metabolites were identified using mass spectrometry based on their molecular masses and fragmentation patterns.

Open access atmospheric pressure chemical ionization Mass spectrometry for routine sample analysis.

We report the introduction and use of an atmospheric pressure chemical ionization liquid chromatography-mass spectrometry instrument that has been designed specifically for use by the synthetic chemist on an open access, walk-in basis. This instrument has been configured with an easy-to-use sample log-in terminal that requires the user to provide only a sample identification number and a user name. Sample analysis takes approximately 4 min and provides the synthetic and medicinal chemist with rapid and reliable mass spectrometry analysis. Since installation of the system, it has analyzed an average of about 80 samples per day and has the capacity to run over 100 samples per day without the intervention of a specialist operator. This capability has eliminated the need for an operator to analyze routine samples and allows the mass spectroscopist more time to deal with problem solving.

Pharmacokinetics, oral bioavailability, and metabolism in mice and cynomolgus monkeys of (2'R,5'S-)-cis-5-fluoro-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl] cytosine, an agent active against human immunodeficiency virus and human hepatitis B virus.

(2'R,5'S-)-cis-5-Fluoro-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl] cytosine (524W91) is a nucleoside analog with potent anti-human immunodeficiency virus and anti-human hepatitis B virus activities in vitro. The pharmacokinetics and bioavailability of 524W91 after oral dosing were studied in mice dosed with 10, 100, and 600 mg of 524W91 per kg of body weight by the oral and intravenous routes. Cynomolgus monkeys were dosed with 10 and 80 mg of 524W91 per kg. In both species, the clearance of 524W91 was rapid, via the kidney, and was independent of dose. In monkeys, the total body clearance of 10 mg of 524W91 per kg was 0.7 +/- 0.1 liter/h/kg, and the volume of distribution at steady state was 0.8 +/- 0.02 liter/kg. The terminal elimination half-life was 1.0 +/- 0.2 h. The absolute bioavailability after oral dosing was 63% +/- 4% at 10 mg/kg. Concentrations of 524W91 in the cerebrospinal fluid were 4% +/- 0.7% of the corresponding levels in plasma. In mice, the total clearance of 10 mg of 524W91 per kg was 2.3 liters/kg/h, and the volume of distribution at steady state was 0.9 liter/kg. Absolute bioavailability in mice after oral dosing was 96% at a dose of 10 mg/kg. The metabolism of orally administered [6-3H]524W91 was studied in cynomolgus monkeys at a dose of 80 mg/kg and in mice at a dose of 120 mg/kg. Monkeys excreted 41% +/- 6% of the radioactive dose in the 0- to 72-h urine, 33% +/- 10% in the feces, and 10% +/- 7% in the cage wash. Unchanged 524W91 was 64% of the total radiolabeled drug recovered in the urine. The glucuronide was a minor urinary metabolite. 5-Fluorouracil was not detected (less than 0.02% of the dose). Mice dosed orally with 120 mg of [6-3H]524W91 per kg excreted 67% +/- 7% of the radiolable in the )- to 48-h urine. Small amounts of the 3' -sulfoxide and glucuronide metabolites were observed in the urine, but 5-fluorouracil was not detected. Good bioavailability after oral dosing and resistance to metabolism recommend 524W91 for further preclinical evaluation.

The use of low-energy collisionally activated dissociation negative-ion tandem mass spectrometry for the characterization of dog and human urinary metabolites of the drug BW 1370U87.

Liquid chromatography (LC) combined with atmospheric pressure chemical ionization mass spectrometry was used to identify phase I and II metabolites of the drug BW 1370U87 in dog and human urine. Additional analysis of individual high-performance liquid chromatograph fractions collected from dog urine by combined gas chromatography/mass spectrometry identified one metabolite which was not detected by LC/MS methods. Using negative-ion LC/MS, the majority of BW 1370U87 metabolites in human urine were identified as glucuronic acid conjugates of phase I oxidative metabolites. The negative-ion fragmentation produced by low-energy collisionally activated decomposition (CAD), studied by tandem mass spectrometry experiments, confirmed that these compounds were drug-related and allowed metabolite structures to be assigned. Product-ion spectra of the metabolites were dominated by the loss of neutral molecules from even-electron deprotonated [M-H]- ions.

Pharmacokinetics, oral bioavailability, and metabolic disposition in rats of (-)-cis-5-fluoro-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl] cytosine, a nucleoside analog active against human immunodeficiency virus and hepatitis B virus.

The pharmacokinetics and metabolism of the potent anti-human immunodeficiency virus and anti-hepatitis B virus compound, (-)-cis-5-fluoro-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl] cytosine (FTC), were investigated in male CD rats. Plasma clearance of 10 mg of FTC per kg of body weight was biexponential in rats, with a half-life at alpha phase of 4.7 +/- 1.1 min (mean +/- standard deviation) and a half-life at beta phase of 44 +/- 8.8 min (n = 5). The total body clearance of FTC was 1.8 +/- 0.1 liters/h/kg, and the oral bioavailability was 90% +/- 8%. The volume of distribution at steady state (Vss) was 1.5 +/- 0.1 liters/kg. Increasing the dose to 100 mg/kg slowed clearance to 1.5 +/- 0.2 liters/kg/h, lowered the Vss to 1.2 +/- 0.2 liters/kg, and reduced the oral bioavailability to 65% +/- 15%. FTC in the brains of rats was initially less than 2% of the plasma concentration but increased to 6% by 2 h postdose. Probenecid elevated levels of FTC in plasma as well as in brains but did not alter the brain-to-plasma ratio. The urinary and fecal recoveries of unchanged FTC after a 10-mg/kg intravenous dose were 87% +/- 3% and 5% +/- 1.6%, respectively. After a 10-mg/kg oral dose, respective urinary and fecal recoveries were 70% +/- 2.5% and 25% +/- 1.6%. Two sulfoxides of FTC were observed in the urine, accounting for 0.4% +/- 0.03% and 2.7% +/- 0.2% of the intravenous dose and 0.4% +/- 0.06% and 2.5% +/- 0.3% of the oral dose. Also observed were 5-fluorocytosine, representing 0.4% +/- 0.06% of the intravenous dose and 0.4% +/- 0.07% of the oral dose, and FTC glucuronide, representing 0.7% +/- 0.2% of the oral dose and 0.4% +/- 0.2% of the intravenous dose. Neither deaminated FTC nor 5-fluorouracil was observed in the urine (less than 0.2% of dose). The high oral availability and minimal metabolism of FTC encourage its further preclinical development.

Novel peptides from adrenomedullary chromaffin vesicles.

The adrenal medulla chromaffin vesicle (CV) contains, on a weight basis, as much soluble protein and peptide as catecholamine. The bulk of the protein is accounted for by chromogranins (Cgr) A, B and C. Additionally, a large variety of neuropeptides and their precursor proteins have been found recently within these vesicles. Nevertheless, fractionation of CV lysates indicates the presence of many more peptides than previously reported. In the hope of finding novel bioactive peptides, we initiated a systematic isolation and characterisation of CV peptides. Bovine CV pellets were prepared by sucrose gradient centrifugation and immediately boiled in water to avoid degradation of native proteins and peptides. The water lysates were fractionated through a battery of reversed-phase and ion-exchange high-performance chromatographic steps. We fully or partially characterised a substantial number of novel peptides derived from CgrA and CgrB. A tetradecapeptide and a 13 kDa extended peptide were derived from the bovine homologue of rat secretogranin III. Peptides corresponding to C-terminal fragments of 7B2 and proteoglycan II were also found. Additionally, several sequences had no known precursors. Of the sequences derived from known precursors some corresponded to fragments bracketed by pairs of basic amino acids, but others were preceded or followed by single basic residues or by unusual putative cleavage sites. Some of these peptides were postranslationally modified (pyroglutamylation, glycosylation, phosphorylation, amidation). A significant degree of structural conservation of some of these peptides across species suggests that they may exert biological effects when cosecreted with catecholamines during splanchnic stimulation.

Identification of a 7B2-derived tridecapeptide from bovine adrenal medulla chromaffin vesicles.

1. A novel tridecapeptide was isolated from extracts of bovine adrenal medulla chromaffin vesicles and the primary structure determined to be SVPHFSDEDKDPE. 2. This peptide is identical to the C termini of human and porcine 7B2 and is highly homologous to the same region of the mouse and Xenopus lavis protein. 3. In all these species the homologous peptide is preceded by a pair of lysine residues, a potential proteolytic processing site. 4. Ser6 is part of a well-conserved casein kinase II consensus phosphorylation sequence. Evidence for phosphorylation of this residue was obtained during Edman sequencing. 5. Thus, this novel adrenal medullary probably arises from the posttranslational processing of the bovine 7B2 protein.

Site and consequences of the autophosphorylation of Ca2+/calmodulin-dependent protein kinase type "Gr".

CaM kinase-Gr is a Ca2+/calmodulin-dependent protein kinase that is enriched in brain and thymus. The enzyme was isolated from rat cerebellum, which contained alpha (M(r) 65,000) and beta (M(r) 67,000) polypeptides, and rat forebrain, which contained only the alpha polypeptide. Both enzyme preparations readily underwent autophosphorylation with dramatic up-regulation of their Ca2+/calmodulin-dependent, as well as-independent, activity. Autophosphorylation also caused a characteristic retardation in the electrophoretic gel mobility of the alpha and beta polypeptides. Treatment of autophosphorylated CaM kinase-Gr with acid phosphatase fully dephosphorylated the enzyme and reversed the changes in electrophoretic migration of both polypeptides. Phosphopeptide mapping indicated that the alpha and beta polypeptides were phosphorylated on identical or homologous sites, which probably induces similar structural and catalytic modifications in the two polypeptides. The actual site(s) of autophosphorylation was determined by the purification and amino acid sequencing of tryptic peptides from 32P-labeled CaM kinase-Gr. The major site of autophosphorylation was localized to a novel N-terminal domain, which is rich in Ser/Thr/Pro residues. The functional and structural studies on CaM kinase-Gr autophosphorylation imply that the enzyme is comprised of two regulatory domains, one on either side of a catalytic domain, followed by a C-terminal, putative association domain. The properties of such a structural model are discussed.

Inactivation of dihydropyrimidine dehydrogenase by 5-iodouracil.

5-Iodouracil was a substrate for bovine liver dihydropyrimidine dehydrogenase (DHPDHase) and was a potent inactivator of the enzyme. NADPH increased the rate of inactivation and thymine protected against inactivation. These findings suggest that 5-iodouracil was a mechanism-based inactivator. However, dithiothreitol and excess 5-iodouracil protected the enzyme against inactivation. Thus, a reactive product, presumably 5-iodo-5,6-dihydrouracil generated through the enzymatic reduction of 5-iodouracil, was released from DHPDHase during processing of 5-iodouracil. Since only 18% of [6-3H]5-iodouracil reduced by DHPDHase was covalently bound to the enzyme and radiolabel was not lost to the solvent as tritium, the partition coefficient for inactivation was 4.5. However, the enzymatic activity was completely titrated with 1.7 mol of 5-iodouracil per mol of enzyme-bound flavin. These results indicate that there was 0.31 mol of enzyme-bound inactivator per mol of enzyme flavin. This suggests there were 3.2 flavins per active site, which is consistent with the report of multiple flavins per enzymic subunit (Podschun, B., Wahler, G., and Schnackerz, K. D. (1989) Eur. J. Biochem. 185, 219-224). DHPDHase was inactivated by 2.1 mol of racemic 5-iodo-5,6-dihydrouracil per mol of active sites. The stoichiometry for inactivation of the enzyme by the nonenzymatically generated enantiomer of 5-iodo-5,6-dihydrouracil was calculated to be 1. Two radiolabeled fragments were isolated from a tryptic digest of DHPDHase inactivated with radiolabeled 5-iodouracil. The amino acid sequences of these peptides were Asn-Leu-Ser-X-Pro-His and Asn-Leu-Ser-X-Pro-His-Gly-Met-Gly-Glu-Arg where X was the modified amino acid containing radiolabel from [6-3H]5-iodouracil. Fast atom bombardment mass spectral analysis of the smaller peptide yielded a protonated parent ion mass of 782 daltons that was consistent with X being a S-(hexahydro-2,4-dioxo-5-pyrimidinyl)cysteinyl residue.