PubMed Health⌕ Search

Biomedical subjects

D Watson

Publications and source records attributed to D Watson.

At least 145 records · Page 8Linked to original sources
PubMed1991

Specific degenerate codons enhanced selective expression of human parathyroid hormone in Escherichia coli.

Specific degenerate codons in the amino-terminal region of a synthetic human parathyroid hormone (PTH) gene exerted dramatic effects on both products and yield of expression of this 84-amino acid polypeptide in Escherichia coli. With adenine-rich degenerate codons constituting the PTH-(1-5) region, intact PTH has been expressed as the only PTH product at 6.5 mg/liter. In contrast, with guanine-rich degenerate codons, the predominent product was analogue PTH-(8-84). Use of cytosine- or thymine-rich degenerate codons generated only a small amount of immunoreactive product (0.2 mg/l). With the amino terminal region reconstituted with adenine-rich degenerate codons, the mid and carboxyl regions of the synthetic gene were also reconstructed to imitate the E. coli-favored codon degeneracy. Expression yielded the intact PTH at 20 mg/liter. Gel electrophoresis and Western blots, with antibodies specific to the amino or carboxyl terminus of PTH, indicated only a single PTH-related polypeptide, with the same mobility as a synthetic intact PTH sample. Amino acid sequencing, composition analysis, mass spectrometry, and the adenylate cyclase bioassays confirmed the purified product as the processed intact PTH.

Amino Acid Sequence↗
PubMed1991

Analysis of vitamin D and its metabolites using thermospray liquid chromatography/mass spectrometry.

A new method is described for the analysis of vitamin D and its metabolites utilizing thermospray (TSP) mass spectrometry as an on-line detector for high performance liquid chromatography. Ionization conditions were optimized for use with isocratic reversed phase chromatography. TSP mass spectrometry was employed in series with a UV absorbance detector to facilitate comparisons between the two methods of detection. Positive ion TSP mass spectra were recorded for vitamin D2, vitamin D3, 25-hydroxyvitamin D3 (25(OH)D3), 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and 24,25-dihydroxyvitamin D3 (24,25(OH)2D3). The spectra contained protonated molecular ions, ammonium adduct ions and fragment ions due to the loss of one or more molecules of water. A comparison of quantitative precision was made by determining UV absorbance and TSP standard curves for vitamin D3 using two different methods: (1) External standard method with post-column (post UV detector) addition of ammonium acetate. (2) As (1) but using the method of internal standards with a closely eluting internal standard (vitamin D2). In each case the quantitative precision (correlation coefficient) for UV absorbance detection was superior owing to intrinsic instability of the TSP ion beam. A stable isotopically labelled internal standard was employed in the development of an assay for 1,25(OH)2D3. The assay was used to quantify in vitro enzymic conversion of 25(OH)D3 to 1,25(OH)2D3 in guinea pig and sheep renal mitochondrial incubations. TSP LC/MS was also applied to analysis of an extract of human blood plasma in which D3 and each of its principal metabolites were identified in a single analysis.

24,25-Dihydroxyvitamin D 3↗
PubMed1991

Regional variation in the abundance of axonal cytoskeletal proteins.

The relative abundance of several axonal cytoskeletal proteins was determined by immunoassay at various sites in the peripheral and central nervous systems of adult rats. Within the peripheral nervous system, the ratio of tubulin to neurofilaments was greatest for nerves composed of unmyelinated axons and least for nerves with large myelinated axons. MAP1 protein was more prominent in unmyelinated fibers; conversely tau proteins were relatively more abundant in large myelinated axons. An immunochemical index of neurofilament phosphorylation was less for unmyelinated fibers than for myelinated ones. In the fimbria-fornix, pyramidal tract, and superior cerebellar peduncle, similar trends were observed: small axons had more MAP1, less tau, and a greater ratio of tubulin to neurofilament proteins. The phosphorylation index was greatest for the superior cerebellar peduncle, the tract with the largest axons. The immunochemical index of neurofilament phosphorylation was greater for the optic nerve than for axonal tracts in the brain proper. These results suggest that development of large myelinated axons is associated with greater neurofilament content, neurofilament phosphorylation, and with greater abundance of tau proteins in the CNS and the PNS; however, quantitative aspects of these relationships differ in the PNS and the CNS.

Animals↗
PubMed1991

Tripartite model of anxiety and depression: psychometric evidence and taxonomic implications.

We review psychometric and other evidence relevant to mixed anxiety-depression. Properties of anxiety and depression measures, including the convergent and discriminant validity of self- and clinical ratings, and interrater reliability, are examined in patient and normal samples. Results suggest that anxiety and depression can be reliably and validly assessed; moreover, although these disorders share a substantial component of general affective distress, they can be differentiated on the basis of factors specific to each syndrome. We also review evidence for these specific factors, examining the influence of context and scale content on ratings, factor analytic studies, and the role of low positive affect in depression. With these data, we argue for a tripartite structure consisting of general distress, physiological hyperarousal (specific anxiety), and anhedonia (specific depression), and we propose a diagnosis of mixed anxiety-depression.

Anxiety Disorders↗
PubMed1991

Interaction between Pseudomonas aeruginosa and Staphylococcus aureus: description of an anti-staphylococcal substance.

The presence of Pseudomonas aeruginosa in the sputum of 191 patients with cystic fibrosis was significantly related (p less than 0.0001) to the absence of Staphylococcus aureus. Cross-streaking tests showed that 40 of 50 clinical strains of P. aeruginosa produced substances that inhibited the growth of S. aureus. When incorporated into agar plates, this antibacterial substance(s) inhibited the growth of 177 of 189 strains of nine staphylococcal species, all of 16 methicillin-resistant S. aureus and 27 of 39 strains of six other gram-positive genera. The substance(s) did not inhibit 23 strains of seven gram-negative genera tested. The antibacterial activity was heat stable and could be extracted into chloroform; activity was retained on Sephadex G-15 (V/Vo approximately 2, Mr less than 500) and eluted as a single peak from high performance liquid chromatography, well separated from pseudomonic acid, pyocyanin and a number of other phenazines.

Anti-Bacterial Agents↗
PubMed1991

Preparation, characterization, and immunogenicity of conjugates composed of the O-specific polysaccharide of Shigella dysenteriae type 1 (Shiga's bacillus) bound to tetanus toxoid.

The background for developing conjugate vaccines for shigellosis composed of the O-specific polysaccharide (O-SP) bound to a protein is described elsewhere (C. Y. Chu, R. Schneerson, and J. B. Robbins, submitted for publication). Briefly, there is direct evidence for type (lipopolysaccharide [LPS])-specific protection after infection with the wild type or with attenuated strains of shigellae. Prospective studies of Israeli armed forces recruits show a correlation between preexisting serum immunoglobulin G (IgG) LPS antibodies and resistance to shigellosis (D. Cohen, M. S. Green, C. Block, R. Slephon, and I. Ofek, J. Clin. Microbiol. 29:386-389, 1991). In order to elicit IgG LPS-specific antibodies to Shigella dysenteriae type 1, the O-SP of this pathogen was purified and bound to tetanus toxoid (TT) by three schemes. The most immunogenic used a modification of a published method (C. Y. Chu, R. Schneerson, J. B. Robbins, and S. C. Rastogi, Infect. Immun. 40:245-256, 1983). The resultant O-SP-TT conjugates were stable and elicited high levels of IgG O-SP antibodies and booster responses in young mice when injected subcutaneously in saline at 1/10 the proposed human dose. Adsorption onto alum or concurrent administration with monophosphoryl lipid A enhanced both the IgG and IgM antibody responses to the O-SP of the conjugate; both the nonadsorbed and adsorbed conjugates elicited higher rises of IgG than of IgM antibodies. Clinical evaluations of S. dysenteriae type 1 O-SP-TT conjugates are planned.

Animals↗
PubMed1991

Depression and decision-making among intravenous drug users.

Two short scales, the TCU Depression Scale and the TCU Decision-making Scale, were psychometrically evaluated in a sample of 145 intravenous drug users. Coefficient alpha reliabilities were .78 for the 6-item TCU Depression Scale and .77 for the 9-item TCU Decision-making Scale. Concurrent validity of the former scale was assessed by correlating scores with those on the Beck Depression Inventory, r = .75. Based on the Beck Depression Inventory Clinical cutoff scores, 83% of the sample showed some depression, with 23% severely depressed, 39% moderately depressed, and 21% mildly depressed. Individuals scoring higher on depression on both tests tended to score lower on decision-making. Significant demographic associations of age, gender, education, and race-ethnicity were found for the depression and decision-making scales. More depression was noted for women, those younger, white, and having less education. Older and more educated intravenous drug users tended to score higher on decision-making. Validity for the depression and decision-making scales was assessed by examining correlations with behaviors. Significant positive correlations were found between depression scores and intravenous use of cocaine only, heroin and cocaine combined, and heroin only. Also, intravenous use of cocaine only and of cocaine and heroin combined were negatively related to decision-making. AIDS sex-risky behavior was positively correlated with depression and negatively correlated with decision-making.

AIDS Serodiagnosis↗
PubMed1991

Informal carers of the dementing elderly: a study of relationships.

This study investigated the problems involved in caring for a dementing person in the community from the perspective of their resident informal carer. It also examined the informal carer's relationships with both the dementing person and the statutory and voluntary services. Symbolic interaction theory was applied to this study since it considers the social meanings that things have as a result of an interactional process. To investigate this process, a qualitative research methodology was employed, comprising a diary, interview and post-contact notes. The sample was gathered from multiple referral sources: health, social and voluntary services. The diagnosis of a dementia was confirmed by the individual's own GP. Many of the results from this study support previous work in the field and four recommendations arise from analysis of the data. These are that formal carers could have a greater awareness of the needs of different groups of informal carers, the needs of informal carers in the very early stages of caring for a dementing person, the informal carer's need for counselling and the different reactions to offers of respite and long-term care which are seen as depending upon the relationship between the informal carer and the dementing person.

Adaptation, Psychological↗
PubMed1991

Changes in bile acid composition in patients with primary biliary cirrhosis induced by ursodeoxycholic acid administration.

We describe a detailed study of the effects of ursodeoxycholic acid administration on bile acid composition of the serum and bile of patients with primary biliary cirrhosis. Gas chromatography-mass spectrometry was used to analyze bile acids from 10 patients with primary biliary cirrhosis before and during ursodeoxycholic acid administration (500 mg/day, corresponding to approximately 8 mg/kg body wt), after group separation of the unconjugated and conjugated fractions by lipophilic anion exchange chromatography. These studies were directed at assessing whether the beneficial role of ursodeoxycholic acid in primary biliary cirrhosis was the consequence of a shift in the hydrophobic/hydrophilic balance of the bile acid pool and whether the hypercholeresis might result from the cholehepatic circulation of unconjugated ursodeoxycholic acid in bile. In basal conditions, the unconjugated bile acids accounted for only 5.5% and 2.5%, respectively, of the total bile acids of serum and bile; cholic acid was the major component of the conjugated fraction of serum and bile (56.0% +/- 4.0%, mean +/- S.E.M.), and ursodeoxycholic acid was present in only trace amounts. The conjugated fraction contained many unusual bile acids (representing 16.5% +/- 1.3% of total) including C25 bile acids, iso-chenodeoxycholic acid and several oxo-bile acids. After ursodeoxycholic acid administration biochemical indices of liver function all improved, but the proportions of the unconjugated bile acids in serum and bile did not significantly change.(ABSTRACT TRUNCATED AT 250 WORDS)

Bile↗
PubMed1991

Chondroid chordoma: case report and literature review.

The case of a 74-year-old woman with chondroid chordoma is presented. This tumor is an uncommon variant of typical chordoma and occurs in less than 1% of all intracranial tumors. The mean age of occurrence is approximately 36 years, 38 years younger than the woman in this study. Classical symptoms of intracranial chordoma were noted in this patient, including headaches, diplopia, third nerve palsy and sixth nerve palsy. Differentiation of this tumor from classic chordoma is important because chondroid chordoma has a substantially superior progress.

Aged↗
PubMed1990

Glutamyl-tRNA synthetases of Bacillus subtilis 168T and of Bacillus stearothermophilus. Cloning and sequencing of the gltX genes and comparison with other aminoacyl-tRNA synthetases.

The glutamyl-tRNA synthetase (GluRS) of Bacillus subtilis 168T aminoacylates with glutamate its homologous tRNA(Glu) and tRNA(Gln) in vivo and Escherichia coli tRNA(1Gln) in vitro (Lapointe, J., Duplain, L., and Proulx, M. (1986) J. Bacteriol. 165, 88-93). The gltX gene encoding this enzyme was cloned and sequenced. It encodes a protein of 483 amino acids with a Mr of 55,671. Alignment of the amino acid sequences of four bacterial GluRSs (from B. subtilis, Bacillus stearothermophilus, E. coli, and Rhizobium meliloti) gives 20% identity and reveals the presence of several short highly conserved motifs in the first two thirds of these proteins. Conserved motifs are found at corresponding positions in several other aminoacyl-tRNA synthetases. The only sequence similarity between the GluRSs of these Bacillus species and the E. coli glutaminyl-tRNA synthetase (GlnRS), which has no counterpart in the E. coli GluRS, is in a segment of 30 amino acids in the last third of these synthetases. In the three-dimensional structure of the E. coli tRNA(Gln).GlnRS.ATP complex, this conserved peptide is near the anticodon of tRNA(Gln) (Rould, M. A., Perona, J. J., Söll, D., and Steitz, T. A. (1989) Science 246, 1135-1142), suggesting that this region is involved in the specific interactions between these enzymes and the anticodon regions of their tRNA substrates.

Amino Acid Sequence↗
PubMed1990

Metabolism of 3-hydroxychrysene by rat liver microsomal preparations.

3-Hydroxychrysene, a metabolite of the polycyclic aromatic hydrocarbon (PAH) chrysene, was metabolised by rat liver microsomal preparations obtained from Arochlor 1254-pretreated rats. Eight major metabolites were isolated by high performance liquid chromatography and characterised by u.v. spectroscopy and a variety of mass spectrometric techniques. The metabolites were unambiguously identified as 9-hydroxy-trans-1,2-dihydroxy-1,2-dihydrochrysene and 9-hydroxy-r-1,t-2,t-3,c-4-tetrahydroxy-1,2,3,4-tetrahydrochrysene and tentatively identified as 3-hydroxy-trans-5,6-dihydroxy-5,6-dihydrochrysene (since chrysene is a symmetrical molecule the 3- and 9-positions are equivalent), 9-hydroxy-trans-3,4-dihydroxy-3,4-dihydrochrysene, 1,2,3-trihydroxy-1,2,3,4-tetrahydrochrysene, an oxidised phenol and two diphenols. These results indicate that 3-hydroxychrysene can be further metabolised via a number of different pathways including those involving the formation of phenol- and triol-epoxides.

Animals↗
PubMed1990

Immunopathology of experimental Brucella abortus strain 19 infection of the genitalia of bulls.

Antibody responses in serum and semen, and immunoglobulin containing cell (ICC) populations in the genitalia of bulls were compared after inoculating Brucella abortus strain 19 into the seminal vesicles of two bulls (ISV route) and into testes in two other bulls (IT route). Bulls seroconverted as early as 1 week post-infection (PI). Peak serum titres as determined by the serum agglutination test (SAT), complement fixation test (CFT) and ELISA occurred at PI weeks 3, 4 and 5 respectively. Highest titres were in IT inoculated bulls. Seminal antibodies against B. arbotus S19 were demonstrated from 2 weeks PI by both the SAT and the Rose Bengal Test (RBT) and highest titres occurred at PI weeks 3 and 4. Examination of immunoglobulins (Ig) in semen, however, revealed no significant differences of Ig isotypes between infected and control animals at any examination time. When bulls were killed at 7 weeks PI, quantitation of ICC in genital sections stained by the peroxidase-anti-peroxidase method revealed an overwhelming predominance of IgG containing cells in inflamed organs. In all cases IgG1- and IgG2-containing cells were prevalent, and present in approximately equal numbers. IgA-containing cells were second in prevalence in inflamed tissues while IgM cells were always in low percentage. High prevalence of ICC in infected genitalia, associated with elevated specific seminal antibodies but not with increased seminal Ig indicates that most Ig remains localised in tissues and is not transferred into genital secretions.

Animals↗
PubMed1990

Vitamin D and mineral metabolism in the very low birth weight infant receiving 400 IU of vitamin D.

STUDY OBJECTIVE: To examine (1) the effect of vitamin D intake (380 to 480 IU daily) on plasma 25-hydroxyvitamin D (25-OHD) and 1,25-dihydroxyvitamin D (1,25-(OH)2D) concentrations and (2) the relationship of 1,25-(OH)2D to calcium and phosphorus absorption and retention in the very low birth weight infant receiving a preterm infant formula. SUBJECTS: Eleven "well" infants with a birth weight and gestational age (mean +/- SD) of 1078 +/- 128 gm and 29 +/- 1.9 weeks, respectively, were studied for a 3-week period. Weight and postnatal age (mean +/- SD) at the beginning of the study were 1132 +/- 56 gm and 16 +/- 6 days, respectively. All infants were fed a preterm infant formula and tolerated a full enteral intake (120 kcal/kg/day) for the duration of the study. INTERVENTIONS: Plasma 25-OHD and 1,25-(OH)2D concentrations were measured at the beginning of the study and at the beginning of each 48-hour balance period. Calcium and phosphorus balance studies (n = 33) were performed weekly. MAIN RESULTS: Plasma 25-OHD (30 +/- 10 ng/ml) and 1,25-(OH)2D (54 +/- 14 pg/ml) concentrations were normal at the beginning of the study. Plasma 25-OHD values did not change, but 1,25-(OH)2D values increased (p less than 0.001) throughout the study. Plasma 1,25-(OH)2D concentrations were not related to calcium or phosphorus absorption and retention, but were a linear function of postconceptional age. CONCLUSIONS: Normal vitamin D status and activity are maintained in the very low birth weight infant fed a high calcium formula (380 to 480 IU of vitamin D daily). Plasma 1,25-(OH)2D concentrations are not related to calcium absorption but are linearly related to maturity.

Calcium↗
PubMed1990

Serum antibody response in adult volunteers elicited by injection of Streptococcus pneumoniae type 12F polysaccharide alone or conjugated to diphtheria toxoid.

Conjugates of an uronic acid-containing capsular polysaccharide (CP), pneumococcous type 12F (Pn12F) bound to diphtheria toxoid (DT), were studied for safety and immunogenicity in adult volunteers. In mice, these conjugates, prepared with the same lot of DT and Pn12F-40234-006, a homogenous CP of high molecular weight, or Pn12-812408, a polydisperse CP with lower-molecular-weight material, were more immunogenic than the Pn12F alone and had T-cell dependent properties (A. Fattom, W. F. Vann, S.C. Szu, A. Sutton, X. Li, B. Bryla, G. Schiffman, J. B. Robbins, and R. Schneerson, Infect. Immun. 56:2292-2298, 1988). Adult volunteers, randomized into three groups, were injected either with one of these two conjugates or with Pnu-Imune, the 23 valent pneumococcus vaccine containing 25 micrograms of Pn12F as one of its components. Volunteers were injected two times, 4 weeks apart, with the Pn12F-DT conjugates and once with the Pnu-Imune. Side reactions following injection of the conjugates of Pnu-Imune were mild and short-lived. At 4 weeks and at 7 months after the first injection, higher levels of Pn12F antibodies were found in the volunteers injected with the conjugates than in the Pnu-Imune group (P less than 0.001). The conjugate prepared with the higher-molecular-weight Pn12F elicited higher levels of antibodies than the conjugate prepared with a lower-molecular-weight Pn12F preparation (P = 0.05). Both conjugates elicited about a 13-fold rise in DT antibodies.

Adolescent↗
PubMed1990

Stimulant medication use by primary care physicians in the treatment of attention deficit hyperactivity disorder.

Treatment of attention deficit hyperactivity disorder (ADHD), one of the most common behavioral disorders in children in the United States, remains controversial because of concern about stimulant medication use. Extending a previous study of pediatricians, the present study surveyed a random national sample of family practitioners and then directly screened 457 patients of 10 pediatricians and family practitioners in two small midwestern cities. Responses to the national survey indicated that stimulant medication remains the main treatment prescribed by primary care physicians for children with ADHD. In the direct patient screening, the prevalence of ADHD diagnoses was 5.3% (pediatricians) and 4.2% (family practitioners) of all elementary-school-aged children screened. Eighty-eight percent of these children were treated with methylphenidate. Although medication was considered an effective treatment by the parents of 85% of the children given the medication, efficacy was unrelated to the accuracy of diagnosis. When explicit DSM-III-R criteria were used, only 72% of those assigned a diagnosis of ADHD by the physicians would have received that diagnosis based on a structured psychiatric interview with the parents and only 53% received that diagnosis based on teacher report of symptoms, even when the child was not receiving medication. Although the majority of physicians (in both the surveys and the direct screenings) reported using at least some behavioral treatments with their patients, parents reported infrequent use of nonpharmacologic forms of therapy, such as behavior modification. These data thus indicate a relatively modest rate of stimulant medication use for ADHD, but a serious underuse of systematic behavioral treatments in primary care.(ABSTRACT TRUNCATED AT 250 WORDS)

Attention Deficit Disorder with Hyperactivity↗