Search PubMed⌕ Search

Biomedical subjects

C Collins

Publications and source records attributed to C Collins.

At least 217 records · Page 12Linked to original sources
PubMed1987

Analysis of nucleotide sequences of two ligninase cDNAs from a white-rot filamentous fungus, Phanerochaete chrysosporium.

An analysis of nucleotide sequences of two types of ligninase cDNAs isolated from the basidiomycete Phanerochaete chrysosporium, designated CLG4 and CLG5, are presented here. The amino acid sequences of the corresponding ligninase proteins, designated LG4 and LG5, respectively, have been deduced from the cDNA sequences. Mature ligninases LG4 and LG5 are preceded by leader sequences containing 28 and 27 amino acids (aa), respectively, and each contains 344 aa residues. The estimated Mrs of mature LG4 and LG5 are 36,540 and 36,607, respectively. Potential N-glycosylation site(s) with the general sequence Asn-X-Thr/Ser are found in both LG4 and LG5. Nucleotide sequence homology between the coding region of CLG4 and CLG5 is 71.5%, whereas the amino acid sequence homology between the two ligninases is 68.5%. The codon usage of ligninases is extremely biased in favor of codons rich in cytosine and guanine. Amino acid sequences of two tryptic peptides of ligninase H8 have exactly matching sequences in ligninase LG5. Also, the sequences of the oligodeoxynucleotide probes, which correspond to the sequences in the tryptic peptides of ligninase H8 and which were used in isolating the ligninase clones from the cDNA library, have exactly matching sequences in CLG5. The experimentally determined N-terminal sequence of purified ligninase H8 is found in the deduced N-terminal amino acid sequence of LG5. These results suggest that CLG5 encodes ligninase H8 and that CLG4 represents a related but different ligninase gene.

Amino Acid Sequence↗
PubMed1987

Homogeneous enzyme immunoassay (EMIT) protocol for monitoring tricyclic antidepressants on the COBAS-BIO centrifugal analyzer.

EMIT tests are available for quantitative determination of the tricyclic antidepressants amitriptyline (AMI), nortriptyline (NORT), imipramine (IMI), and desipramine (DMI). An extraction step before analysis eliminates cross-reacting polar metabolites. Excellent correlation between EMIT and high-performance liquid chromatography (HPLC) has been previously established. Most published protocols for using EMIT reagents on COBAS-BIO centrifugal analyzers were designed for analytes present at 1-50 mg/L in serum. AMI, NORT, IMI, and DMI are usually present at far less than 1 mg/L. We describe a COBAS-BIO EMIT protocol for assaying these analytes. Patient sample correlation between COBAS-BIO EMIT and EMIT-AutoLab were greater than 0.99. Between-run precision for single-point determinations was comparable to SYVA AutoLab performance [less than or equal to 11% at 40 micrograms/L AMI, NORT, IMI (80 micrograms/L DMI), and less than or equal to 4% at 200 micrograms/L AMI, NORT, IMI (400 micrograms/L DMI)]. With stored-curve updating, working reagents were usable for at least 14 days (AMI) or 23 days (DMI).

Antidepressive Agents, Tricyclic↗
PubMed1986

Insulin-like growth factor I receptor primary structure: comparison with insulin receptor suggests structural determinants that define functional specificity.

To identify structural characteristics of the closely related cell surface receptors for insulin and IGF-I that define their distinct physiological roles, we determined the complete primary structure of the human IGF-I receptor from cloned cDNA. The deduced sequence predicts a 1367 amino acid receptor precursor, including a 30-residue signal peptide, which is removed during translocation of the nascent polypeptide chain. The 1337 residue, unmodified proreceptor polypeptide has a predicted Mr of 151,869, which compares with the 180,000 Mr IGF-I receptor precursor. In analogy with the 152,784 Mr insulin receptor precursor, cleavage of the Arg-Lys-Arg-Arg sequence at position 707 of the IGF-I receptor precursor will generate alpha (80,423 Mr) and beta (70,866 Mr) subunits, which compare with approximately 135,000 Mr (alpha) and 90,000 Mr (beta) fully glycosylated subunits.

Amino Acid Sequence↗
PubMed1986

An instrument to measure coping responses in employed mothers: preliminary results.

The purpose of this study was to develop a survey instrument to measure coping responses in working mothers. Coping responses were defined as efforts to prevent, avoid, or control emotional distress. Based on interviews, literature review, and a survey of existing instruments, items were developed to measure these three functions of coping behaviors. The instrument was distributed to 133 married mothers who worked at least 15 hours per week outside the home; response rate was 93%. Nine subscales to measure coping responses in working mothers were identified. Alpha reliability coefficients for the subscales range from .65-.90. Construct validity of the subscales was investigated by examining specified relationships between subscale scores and role strain measures. All but one of the subscales were significantly correlated in the predicted direction with at least one of the role strain measures. The final instrument, the Coping Responses Inventory (CRI), is comprised of 59 Likert format items from which nine subscale scores can be calculated. Some aspects of the reliability and validity of this instrument have been investigated, but confirmation of the findings await further study. Potential uses of the CRI are as an instrument in survey research and as an exploratory tool in counseling interventions with employed women with children.

Adaptation, Psychological↗
PubMed1986

Stressor-provoked response patterns in a swim task: modification by diazepam.

When placed in a water-filled arena in which one area is illuminated mice tend to remain in the illuminated region. Moreover, in a forced-swim task mice initially exhibit vigorous responding followed by a rapid decay of active swimming, and the adoption of a characteristic floating posture. Immediately following exposure to inescapable shock the response invigoration was appreciably enhanced, as was the tendency to remain in the illuminated region of the arena. Administration of low doses of diazepam (0.5 and 1.0 mg/kg) prior to testing effectively eliminated the response invigoration, as well as the response of approaching the illuminated region of the arena. It is proposed that the behavioral variations evident soon after uncontrollable shock are related to a transient increase of anxiety or vigilance. Moreover, it is suggested that several time-dependent behavioral variations associated with inescapable shock may be related to alterations of anxiety.

Animals↗
PubMed1986

Double blind: double talk or are there ways to do better research.

In an attempt to counteract placebo effects, scientists studying the effectiveness of medication often use the 'double blind' trial. Unfortunately, in less than 5% of the studies reported in major medical and psychiatric journals was there a check to determine whether patients and observers were blind. Between 1972 and 1983 there was increasing reliance on active placebos which attempt to mimic the effects of the medication. It is unlikely however, that patients are not aware of significantly different physiologic changes within them resulting from the different chemicals. Whenever a physician informs a subject that they may be on placebo or active treatment medication, they will spend much time in trying to guess when they are taking which. In these situations Philip's paradox will apply. This states that the more potent a therapeutic variable the less likely its efficacy can be 'proven' in a double-blind study. One can only 'prove' that medication is no more effective than placebo. To have a truly blind procedure, the active placebo must have identical physiological effects to those of the medication being studied. We are now using the patient's and the observer's awareness of changes as useful information to obtain: a guess factor, the percentage of correct guesses whether the patient is on medication or placebo; a direction factor, whether the patient considers the change beneficial or detrimental; an attributional factor, whether the change is considered to result from medication or other intervening variables. This information is usually reliable and can be analyzed with the usual statistical procedures.

Attitude to Health↗
PubMed1986

Activation of complement by immunoglobulin M is impaired by the substitution serine-406----asparagine in the immunoglobulin mu heavy chain.

We have isolated and analyzed the DNA encoding the mu heavy chain constant region of a mutant IgM that is defective in initiating complement-dependent cytolysis. By assaying the expression of mu-chain genes that were constructed in vitro from mutant and wild-type gene segments, we have mapped the mutation into a 555-base-pair segment that spans part of the third and fourth constant region domains. In this segment there is one nucleotide change, such that the mutant mu-chain gene encodes asparagine rather than the normal serine at amino acid position 406 in the third constant domain. We have used site-directed mutagenesis to introduce a comparable mutation into the normal mu-chain gene and confirmed that this substitution causes the production of IgM with the original mutant phenotype. Evidence is also provided that the serine-406----asparagine substitution might cause the mutant mu chain to be abnormally glycosylated.

Base Sequence↗
PubMed1986

Equivalent forms of the Boston Naming Test.

In order to develop a test of naming ability that is sensitive to changes in performance on repeated testing, but is unbiased by practice effects, the 85 items of the Boston Naming Test (BNT) were divided into two 42-item forms. Both forms were given to 15 healthy adult subjects, 24 patients with a clinical diagnosis of Alzheimer's disease, and 17 patients with other brain lesions. The reliability of the BNT was high as measured by coefficient alpha and interitem correlations. Performance on the two forms of the test was similar as indicated by mean scores and by correlations between scores. The BNT score includes uncued (spontaneous) and cued responses. When uncued responses were analyzed separately, the reliability and equivalence of the forms remained strong. Using uncued scores therefore does not alter the psychometric properties of the test, and considerably reduces administration time. The modification of the BNT described here should be useful in studies in which repeated measurements are obtained for the purpose of detecting changes in naming ability.

Alzheimer Disease↗
PubMed1986

Geographic variation in infant loss of maternal measles antibody and in prevalence of rubella antibody.

Maternal and cord measles and rubella antibodies were compared in 15 populations from Brazil, Ecuador, Chile, India, Jordan, Nigeria, South Africa, Taiwan, and the United States. Review of the literature concerning these countries showed that a higher proportion of children 6-12 months of age responded immunologically to measles vaccine in areas with low per capita product than in wealthier populations. The authors show that this difference reflects differences in maternal antibody titer and differences in efficiency of transport of measles immunity across the placenta. No variation in the half-life of passive measles immunity in the infant was found in comparing three geographic areas. When these biologic factors are fully evaluated, it should be possible to predict the response to be expected from vaccination at any particular age without directly testing the vaccine in children below and above generally recommended ages for vaccination. With regard to rubella, high antibody prevalence rates were found in most of the developing countries, as well as in the United States, and these countries are therefore unlikely to encounter widespread problems with congenital rubella. However, Taiwan, and all of four areas of Brazil have prevalence rates which are no higher than those which pertained in the United States prior to establishment of the rubella immunization program. The authors believe that protection of the infants in these countries is a matter of high priority, but that, if approached hastily, it could exacerbate the problem.

Adult↗
PubMed1986

Connective tissue abnormalities in MRL/1 mice.

Pathological changes in the connective tissue of the limbs of MRL/1 mice are described. Focal infiltrates of polymorphs or large mononuclear cells, or both, were seen both in synovial lining and subcutaneous tissue. Infiltrates were associated with vasculitis in some cases. Deposits of amorphous material were seen in and around joints and in foot pads. The material was more particulate and refractile than typical 'fibrinoid' and showed a positive Feulgen reaction. It was not surrounded by palisading cells and when seen in synovial tissue was not usually associated with changes in synovial lining cells. No obvious difference was seen between intra-articular and extra-articular lesions. Lesions in subcutaneous tissue occurred exclusively in the foot pads. Lymphocyte infiltration was not prominent at any site and no follicle formation was seen. Of two colonies studied, only one showed a significant increase in lining cell numbers in synovial tissue. Exercised animals had a similar distribution and severity of disease to those of matched controls. All lesions described were distinguishable from non-specific inflammatory lesions in normal control mice and MRL/++ mice on assessment of unmarked sections. The relation between these connective tissue lesions and the changes found in human chronic synovitis is discussed.

Animals↗
PubMed1986

The effect of systemic beta-2 adrenergic agonist therapy on the pulmonary hypertensive response to chronic hypoxia in rats.

Chronic hypoxia produces polycythemia, pulmonary hypertension, muscularization of peripheral pulmonary arteries, and right ventricular hypertrophy. The present study was designed to investigate the effects of systemic administration of a beta-2 adrenergic agonist on these responses. Male Wistar rats (9 or more in every group) were maintained in room air or 10% oxygen for 28 days. In the first experiment, they were treated with albuterol at various doses (0.05 mg/kg, 0.1 mg/kg, 0.5 mg/kg) twice during exposure to intermittent hypoxia (10 h/day). In the second experiment, rats were treated with albuterol 2.5 mg/kg subcutaneously twice daily during continuous hypoxia. Control animals in normoxia and hypoxia received 0.1 ml saline at equivalent times. All hypoxic groups developed polycythemia, significantly increased right ventricular systolic pressure, and right ventricular hypertrophy. At doses of albuterol that did not produce cardiac hypertrophy in normoxia, treatment had no effect on the development of right ventricular hypertrophy. With lower doses of albuterol in hypoxia, there was a trend towards an increase in hematocrit, but overall this did not reach significance. Treatment with high dose albuterol in continuous hypoxia significantly increased the hematocrit and enhanced the remodeling of the pulmonary vasculature (Hematocrit: saline-treated, 57.7 SEM 1.9; albuterol-treated, 63.4 SEM 1.7; p less than 0.05. Percentage of thick-walled peripheral vessels: saline-treated, 19.4 SEM 0.60; albuterol-treated, 22.7 SEM 0.85; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Agonists↗
PubMed1986

Dental insurance and the oral health of preschool children.

Using data from the Rand Health Insurance Experiment, the effects of cost-sharing plans on the health of the primary teeth in 264 children aged 3 to 5 years were investigated. From six areas in the United States, families were assigned at random to different dental and medical insurance plans. The plans varied in the amount of required cost sharing. Families participated in the study for 3 (70%) or 5 (30%) years. Children covered by the plan (requiring no cost sharing) had significantly fewer decayed teeth and deft (decayed, extracted, and filled teeth) at the end of the study than did children covered by the cost-sharing plans. No differences existed among plans in the number of extracted and restored teeth. Children of middle- and low-income families benefited most from having access to free dental care.

Child Health Services↗
PubMed1986

Quantitative homogeneous enzyme immunoassays for amitriptyline, nortriptyline, imipramine, and desipramine.

We describe specific EMIT homogeneous enzyme immunoassays for amitriptyline, nortriptyline, imipramine, and desipramine in patients' serum samples. Before analysis, an easily performed extraction step involving the use of 500 microL of sample and a 1-mL disposable column eliminates cross-reacting polar metabolites. The range of the standard curve for the first three drugs is 25 to 250 micrograms/L, and for desipramine is 50 to 500 micrograms/L. Within-run and between-run CVs are less than 10% throughout the range of the assays. Results for patients' samples obtained by this method and by "high-performance" liquid chromatography compare well, showing a slope range of 0.94-1.04 and correlation coefficients ranging from 0.93 to 0.96, depending on the assay.

Amitriptyline↗
PubMed1985

Endoscopic laser treatment of vascular anomalies of the upper gastrointestinal tract.

Vascular anomalies of the gastrointestinal tract are an important source of both acute and chronic blood loss. They present difficult management problems as they are often multiple, involving more than one part of the gastrointestinal tract, and may give rise to bleeds of increasing frequency and severity over a period of many years. We present the results of endoscopic argon and Nd YAG laser treatment of 18 patients with documented recurrent, severe haemorrhage from vascular lesions of the upper gastrointestinal tract with follow up of up to five years. Four patients with hereditary haemorrhagic telangiectasia, five with single angiodysplasias and three with multiple angiodysplasias have had their transfusion requirements reduced to minimal levels after one or more courses of laser treatment. Two of these have required no blood for over two years despite previous total requirements of 52 and 129 units of blood. Four patients were submitted to surgery (two in whom the laser failed to control haemorrhage and two who did not have immediate access to laser therapy at the time of severe bleed). Two of these, however, bled again soon afterwards. Two patients are still undergoing courses of laser therapy although have already shown reductions in transfusion requirements. Both lasers were effective. The Nd YAG laser appears to produce better long term results as its greater penetration makes it possible to ablate the main areas of vascular ectasia in the submucosa, although it does have a slightly higher risk of causing haemorrhage in the first few days after treatment.

Adult↗
PubMed1985

Detection of cross-reactive anti-DNA antibody idiotypes on renal tissue-bound immunoglobulins from lupus patients.

Cross-reactive anti-DNA antibody idiotypes have been identified on tissue-bound immunoglobulins in a study of renal biopsies from 26 systemic lupus erythematosus (SLE) patients. 12 (46%) biopsies were shown to have one or both the idiotypes tested for by anti-idiotypic reagents. The idiotypes were identified in the glomerular basement membrane, the mesangial cell cytoplasm, and in focal tuft proliferations. In contrast, in none of 24 immunoglobulin-positive disease control biopsies could either idiotype be demonstrated. Blocking studies in two patients indicated that the idiotypes were on anti-DNA antibodies. These findings indicate that some tissue-bound auto-antibodies are derived from related families of high-frequency germ line genes that are expressed in SLE patients. The potential role of anti-idiotypic therapy in SLE is discussed.

Antibodies↗
PubMed1985

Water and Nepal.

Explore the source record for details and available documents.

Disease Reservoirs↗