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Biomedical subjects

J Webb

Publications and source records attributed to J Webb.

At least 91 records · Page 5Linked to original sources
PubMed1995

Purification, characterization, and cloning of a heme-binding protein (23 kDa) in rat liver cytosol.

A heme-binding protein (designated HBP23) has been purified from rat liver cytosol using heme-affinity chromatography and either reverse-phase high-performance liquid chromatography or sequential ion-exchange chromatography. The protein (23 kDa) binds heme with an affinity (Kd = 55 nM) higher than that of the abundant cytosolic heme-binding proteins, heme-binding protein (HBP)/liver fatty acid-binding protein (L-FABP) and the glutathione S-transferases (GSTs) (Kd = 100-200 nM). HBP23 is present in the cytosol of liver, kidney, spleen, small intestine, and heart, with the liver showing the highest content. A cDNA coding the 23-kDa protein was cloned using reverse transcription polymerase chain reaction with degenerative oligonucleotides derived from partial amino acid sequences. The cloned cDNA encoded 199 amino acids, and its amino acid sequence showed no homology to HBP/L-FABP, GSTs, or any other heme-binding proteins or hemeproteins. Homology search showed that HBP23 is highly homologous to mouse macrophage 23-kDa stress protein, which is inducible by oxidant stress in peritoneal macrophages [Ishii, T., Yamada, M., Sato, H., Matsue, M., Taketani, S., Nakayama, K., Sugita, Y., and Bannai, S. (1993) J. Biol. Chem. 268, 18633-18636]. Thioredoxin peroxidase as well as HBP23 and the mouse macrophage 23-kDa stress protein are members of the peroxiredoxin family, a recently recognized class of antioxidant proteins [Chae, H. Z., Chung, S. J., & Rhee, S. G. (1994) J. Biol. Chem. 269, 27670-27678]. An increase in HBP23 mRNA was observed in Hepa 1-6 cells after treatment with heme and cadmium and during liver regeneration after partial hepatectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1995

The value of critical incident analysis as an educational tool and its relationship to experiential learning.

Experiential learning and teaching strategies designed to facilitate this, have become popular in nursing and midwifery education in recent years. It is advocated that such learning enables the development of knowledge, skills and attitudes grounded in practice through the use of reflection on action. One strategy that may be utilised by nursing/midwifery educators to develop reflective ability in both themselves and students is critical incident analysis. It is suggested that critical incident analysis has value and is appropriate for developing interpersonal skills and self-awareness. It is proposed that critical incident analysis is a valuable educational tool which enables nursing/midwifery students to draw on past experiences and make sense of them, not only facilitating learning from clinical practice but also going some way towards bridging the gap between theory and practice.

Education, Nursing↗
PubMed1995

Characterization of a ubiquitinated protein which is externally located in African swine fever virions.

An antiserum was raised against the African swine fever virus (ASFV)-encoded ubiquitin-conjugating enzyme (UBCv1) and used to demonstrate by Western blotting (immunoblotting) and immunofluorescence that the enzyme is present in purified extracellular virions, is expressed both early and late after infection of cells with ASFV, and is cytoplasmically located. Antiubiquitin serum was used to identify novel ubiquitin conjugates present during ASFV infections. This antiserum stained virus factories late after infection, suggesting that virion proteins may be ubiquitinated. This possibility was confirmed by Western blotting, which identified three major antiubiquitin-immunoreactive proteins with molecular masses of 5, 18, and 58 kDa in purified extracellular virions. The 18-kDa protein was solubilized from virions at relatively low concentrations of the detergent n-octyl-beta-D-glucopyranoside, indicating that it is externally located and is possibly in the virus capsid. The 18-kDa protein was purified, and N-terminal amino acid sequencing confirmed that the protein was ubiquitinated and was ASFV encoded. The ASFV gene encoding this protein (PIG1) was sequenced, and the encoded protein expressed in an Escherichia coli expression vector. Recombinant PIG1 was ubiquitinated in the presence of E. coli expressed UBCv1 in vitro. These results suggest that PIG1 may be a substrate for UBCv1. The predicted molecular masses of the PIG1 protein and recombinant ubiquitinated protein were larger than the 18-kDa molecular mass of the ubiquitinated protein present in virions. Therefore, during viral replication, a precursor protein may undergo limited proteolysis to generate the ubiquitinated 18-kDa protein.

African Swine Fever Virus↗
PubMed1995

Evaluation of myocardial infarction therapy at a Canadian tertiary referral hospital.

OBJECTIVE: To evaluate the appropriateness of acute and postmyocardial infarction (MI) treatment. DESIGN: A retrospective chart review. SETTING: Tertiary care teaching hospital. PATIENTS: All patients admitted with a potential MI or who experienced an MI during their hospital stay from November 18, 1991 to September 20, 1992. RESULTS: For acute treatment, thrombolytics, acetylsalicylic acid (ASA) and intravenous beta-blockers were used in 82%, 96% and 39% of eligible patients with a median time delay of 1.4, 4.4 and 1.8 h, respectively. For post-MI treatment, ASA, oral beta-blockers, warfarin and angiotensin-converting enzyme inhibitors were used in 93%, 68%, 50% and 71% of eligible patients, respectively. CONCLUSIONS: ASA use was considered acceptable while the other therapies were underused. The time delays in the initiation of therapies were also considered longer than desirable. Ongoing audit may aid in improving the quality of care in future patients with an MI.

Adrenergic beta-Antagonists↗
PubMed1994

Antinociceptive and toxic effects of (+)-epibatidine oxalate attributable to nicotinic agonist activity.

1. Epibatidine is an analgesic substance, isolated from the skin of the poisonous frog Epipedobates tricolor, for which the mechanism of action was previously unknown. 2. The IC50 of synthetic (+)-epibatidine oxalate (the naturally occurring isomer) for [3H]-nicotine binding to rat whole-brain membranes was 0.1 nM. The (-)-isomer also exhibited high affinity (IC50 = 0.2 nM). 3. (+)- and (-)-Epibatidine exhibited much lower affinity for displacement of the muscarinic ligand [3H]-N-methylscopolamine binding to rat cortical membranes (Kapp = 6.9 microM and 16.0 microM respectively). The (+)-enantiomer of epibatidine had an antagonist/agonist (NMS/oxo-M) binding ratio of 4.2 This is consistent with a muscarinic antagonist profile. 4. (+)-Epibatidine oxalate (10 microM) did not cause significant (> 30%) displacement of radioligand binding to opioid, excitatory amino acid, benzodiazepine, 5-HT, dopamine, adrenaline or peptide receptors. 5. (+)- and (-)-Epibatidine (5-20 micrograms kg-1 s.c.) doubled response latency in the mouse hot-plate test. Antinociception and behavioural depression induced by (+)-epibatidine (5 micrograms kg-1) was fully blocked by the nicotinic antagonists mecamylamine (2 mg kg-1 s.c.) or dihydro-beta-erythroidine (2 mg kg-1 s.c.). The muscarinic antagonist scopolamine (0.4 and 10 mg kg-1 s.c.) caused partial reversal of antinociception induced by (+)-epibatidine in mice, but not in rats. 6. These findings demonstrate that (+)-epibatidine oxalate salt is a highly selective and potent nicotinic analgesic agent.

Analgesics↗
PubMed1994

Angioplasty of large diameter coronary arteries and saphenous vein grafts utilizing modified appropriately large diameter balloon dilatation catheters.

Standard coronary angioplasty balloons have generally not been available in diameters exceeding 4 mm. Consequently angioplasty of larger arteries and grafts is commonly performed with undersized balloons. "Hugging balloon" techniques and the use of peripheral angioplasty balloons introduced without a guiding catheter have been advocated. We utilized oversized (4.5--6.0-mm diameter) modified angioplasty balloons to perform angioplasty in 20 patients with large coronary arteries and saphenous vein grafts. Oversize balloons were used in conjunction with otherwise standard coronary angioplasty equipment and intracoronary stents.

Adult↗
PubMed1994

Diagnostic evaluation of short children with height 3 SD or more below the mean.

Most children who are more than 2 SD below the mean in height (less than third percentile) have no definable cause and are considered short-normal, but for children who are 3 SD below the mean (the lowest 0.13%), the prevalence of organic disease is known to be considerably greater. To better define the frequency of different diagnoses in this subgroup and to identify useful clinical findings, we reviewed the charts of all children referred for growth evaluation over a 10-year period who were > or = -3 SD in height, > 2 years old, and prepubertal. Of 60 patients (36 males and 24 females), 22% had constitutional growth delay (CGD), 23% had growth hormone deficiency (GHD), 13% had Turner syndrome, and 22% had various forms of primary growth failure (mostly associated with intrauterine growth retardation). Eight percent had very slow growth over a prolonged period but no definable cause, and 12% did not fall into any of the above groups. For differentiating GHD from CGD, a subnormal height velocity for age during a 4- to 12-month observation period, a low insulin-like growth factor-1/somatomedin C (IGF-1/Sm-C), and low total or free T4, with normal TSH, were all highly predictive of a diagnosis of GHD.

Body Height↗
PubMed1993

Antagonism of Pseudomonas cepacia against phytopathogenic fungi.

Two strains of Pseudomonas cepacia, RJ3 and ATCC 52796, have been identified as potential antagonists of fungal plant pathogens. We have compared the antagonistic activity of these two strains against various fungal pathogens. Although both strains displayed high levels of antagonism, ATCC 52796 was slightly more antagonistic than RJ3. The antagonist from RJ3 has been identified as the antifungal compound pyrrolnitrin after purification by HPLC and characterization by UV, IR, NMR, and mass spectroscopy. Both strains also antagonized the fungi by production of volatile compound(s), which have not yet been identified. Both strains are similar with respect to in vitro antagonism, mechanism of antagonism, and sensitivity to antibiotics.

Antibiosis↗
PubMed1993

Chlorinated dibenzo-p-dioxins and dibenzofurans and the human immune system. 1. Blood cell receptors in volunteers with moderately increased body burdens.

Using monoclonal antibodies (mAbs) and flow cytometry, we studied a variety of surface receptors on lymphocyte subpopulations of workers with moderately increased body burdens of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and of other polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF), expressed here as International-Toxicity Equivalencies (I-TE). The hypothesis to be tested was whether or not humans exhibit a similar susceptibility to PCDDs/PCDFs with respect to the surface receptors found previously to respond to small doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in Callithrix jacchus. These are: helper-inducer (memory) T cells (CD4+CD45R0+CD45RA-CD29highCD11a+), CD20+ B cells, and cytotoxic T cells (CD8+CD56+/CD57+). Furthermore, 68 triple-labellings with mAbs were performed on the cells of each volunteer to possibly generate further hypotheses. It was evaluated whether any of the variables might be used as a biomarker of effects for this class of compounds. There were two main goals: (1) to evaluate whether workers with a moderately increased PCDD/PCDF-body burden [25-140 ppt TCDD or 104-522 ppt I-TE in blood fat] exhibit changes in the surface receptors of white blood cells, as observed in previous studies in non-human primates, and (2) to clarify whether persons at the upper range [10-23 ppt TCDD or 30-90 ppt I-TE in blood fat] of the body burden reference values of a not particularly exposed population show detectable deviations in these immunological variables, when compared with persons at the lower and medium range [1-3 ppt TCDD or 9-29 ppt I-TE] of these body burden reference values. Regression analysis of our data revealed slight trends for some of the biomarkers (e.g. CD45R0+). With one exception, these were all increases. None of the alterations observed are of medical relevance. The slight increase in the percentage of CD4+CD45R0+ cells remained significant even after covariant analysis taking age-related changes into account. Altogether, the data do not provide any evidence to support an assumption that moderately increased body burdens of PCDDs/PCDFs in adults induce decreases in the cellular components of the human immune system. Adult humans certainly are less susceptible to this action of PCDDs/PCDFs than adolescent Callithrix jacchus.

Adult↗
PubMed1993

Teacher ratings of student risk for substance use as a function of specialized training.

The purpose of this study was to determine if teachers' abilities to identify accurately students who are at risk for substance abuse can be improved through attendance at a specialized training program. Sixty-three eighth-grade teachers participated in the study. Of these, thirty-six teachers participated in the training sequence (intervention group), while the remaining twenty-seven teachers served as a comparison group. All eighth-grade students in the school district were surveyed regarding their substance usage. Teachers rated the students regarding their risk for substance usage. Teachers' ratings and students' reported substance usage were compared to assess the percentage of matching responses. After training, the intervention teachers provided more accurate ratings among usage categories than did the comparison teachers. The trained teachers were better at correctly identifying the students who were at risk for substance use.

Adolescent↗
PubMed1992

A low-spin iron complex in human melanoma and rat hepatoma cells and a high-spin iron(II) complex in rat hepatoma cells.

Human melanoma and rat hepatoma cells cultured in the presence of low concentrations (2.5 microM) of low-molecular-weight iron (Fe) chelates and Fe-transferrin complexes have been studied with 57Fe Mössbauer spectroscopy. The spectra show that holoferritin is only a minor fraction of the total iron present in the cells. The major form of Fe was in a low-spin state unlike the high-spin Fe(III) found in ferritin. Only about 10% of the Fe could be attributed to ferritin. In addition, the hepatoma cells had a high-spin Fe(II) spectral component which made up about 20% of the Fe present.

Animals↗