Search PubMed⌕ Search

Biomedical subjects

B Green

Publications and source records attributed to B Green.

At least 19 recordsLinked to original sources
PubMed2000

Multiple posttranslational modifications at distinct sites contribute to heterogeneity of the lipoprotein cytochrome bo(3).

The heme-copper cytochrome oxidase of Escherichia coli (cytochrome bo(3)) was tagged with oligohistidine at the C-terminus of the small noncatalytic subunit IV. After detergent solubilization, the enzyme was purified by a one-step procedure with immobilized metal affinity chromatography. Using different cytochrome bo(3) constructs as reference, the products were investigated by mass spectroscopical and immunological methods. Several posttranslational modifications of subunits II, III, and IV were observed: (1) N-terminal methionines of subunits III and IV are split off. (2) Fifty percent of subunit III polypeptides are acetylated, presumably at the N-terminal alanine. (3) Lipoprotein processing of subunit II involves cleavage of the signal peptide. (4) Maturation of subunit II [Ma, J., Katsonouri, A., and Gennis, R. B. (1997) Biochemistry 36, 11298-11303] alters the structure of the N-terminal cysteine by N-palmitoylation and S-glyceryldipalmitoylation. (5) A hexapeptide is split off from the C-terminus of subunit II. This happens subsequently to the N-terminal lipoprotein processing step and is dependent on the growth state of cells.

Amino Acid Sequence↗
PubMed2000

Implications of the distribution of Albumin Naskapi and Albumin Mexico for new world prehistory.

The known distributions of two mutational variants of the albumin gene that are restricted to Mexico and/or North America, Albumin Mexico (AL*Mexico) and Albumin Naskapi (AL*Naskapi), were expanded by the electrophoretic analysis of sera collected from more than 3, 500 Native Americans representing several dozen tribal groups. With a few exceptions that could be due to recent, isolated cases of admixture, AL*Naskapi is limited to groups that speak Athapaskan and Algonquian, two widely distributed language families not thought to be related, and to several linguistically unrelated groups geographically proximate to its probable ancestral homeland. Similarly, AL*Mexico is limited to groups that speak Yuman or Uto-Aztecan, two language groups in the American Southwest and Baja California not thought to be closely related to each other, and to several linguistically unrelated groups throughout Mexico. The simultaneous consideration of genetic, historical, linguistic, and archaeological evidence suggests that AL*Naskapi probably originated on the northwestern coast of North America, perhaps in some group ancestral to both Athapaskans and Algonquians, and then spread by migration and admixture to contiguous unrelated, or distantly related, tribal groups. AL*Mexico probably originated in Mexico before 3,000 years BP then spread northward along the Tepiman corridor together with cultural influences to several unrelated groups that participated in the Hohokam culture.

Albumins↗
PubMed2000

Removal of UroLume endoprosthesis: experience of the North American Study Group for detrusor-sphincter dyssynergia application.

PURPOSE: We present the experience of the North American UroLume Multicenter Study Group with removal of the UroLume endoprosthesis. MATERIALS AND METHODS: A total of 160 neurologically impaired patients were enrolled in the North American UroLume Multicenter Study Group for detrusor external sphincter dyssynergia application. Analysis was performed in 2 groups of patients in which the device was removed during insertion and after implantation, respectively. RESULTS: Device retrieval was required during insertion in 21 patients (13%) mainly due to misplacement or migration in 17. Extraction was done with minimal complications and in all but 2 cases subsequent UroLume implantation was successful. Of 158 men with the device in place 31 (19.6%) required removal. In 34 procedures 44 devices were removed, mainly due to migration. Time from implantation to removal ranged from 4 days to 66 months (mean 22 months). The UroLume was removed en bloc in 20 cases and in parts or wire by wire in 19. The majority of patients had no or minimal complications after extraction. Only 2 patients had serious temporary complications, including bleeding and urethral injury, with no lasting consequences. No malignancy developed as a result of UroLume insertion. CONCLUSIONS: While there is a potential for urethral injury and bleeding, UroLume endoprosthesis removal is largely a simple procedure with minimal complications and consequences.

Humans↗
PubMed2000

FRAP DNA-dependent protein kinase mediates a late signal transduced from ultraviolet-induced DNA damage.

Ultraviolet radiation induces signal transduction at both early (<6 h) and late (>6 h) times after exposure. The inflammatory and immunosuppressive cytokine tumor necrosis factor alpha is induced at late times, and is induced by ultraviolet-induced DNA damage, as defects in DNA repair increase, and enhanced photoproduct repair reduces, tumor necrosis factor alpha expression. Here we show that late tumor necrosis factor alpha gene expression is sensitive to rapamycin, implicating FKBP12-rapamycin-associated protein, a member of the DNA protein kinase family, as a signal transducer of ultraviolet-induced DNA damage. FKBP12-rapamycin-associated protein was localized in the nucleus of keratinocytes and its level was increased following ultraviolet irradiation. Immuno- precipitated FKBP12-rapamycin-associated protein was stimulated by ultraviolet-irradiated DNA to phosphorylate p53 in vitro, and in vivo rapamycin reduced ultraviolet induction of p53 by 20%. Rapamycin further inhibited the ultraviolet-induced phosphorylation of the FKBP12-rapamycin-associated protein downstream target kinase p70S6K. In mice, topical application of rapamycin before ultraviolet exposure protected against suppression of the contact hypersensitivity that is a hallmark of ultraviolet-induced cytokine gene expression. These results demonstrate that the FKBP12-rapamycin-associated DNA protein kinase transduces the signal of ultraviolet-induced DNA damage into production of immunosuppressive cytokines at late times after ultraviolet irradiation.

DNA↗
PubMed2000

Bacterial pneumonia in hospitalized patients with HIV infection: the Pulmonary Complications, ICU Support, and Prognostic Factors of Hospitalized Patients with HIV (PIP) Study.

STUDY OBJECTIVES: To describe the causative organisms and factors associated with bacterial pneumonia and to assess its impact on the outcome of hospitalized patients with HIV. DESIGN: Prospective, observational. SETTING: A university-affiliated medical center. METHODS: We included 1,225 consecutive hospital admissions, from April 1995 through March 1998, of 599 adults with HIV. We collected data on APACHE II (acute physiology and chronic health evaluation II) score, leukocyte and CD4+ lymphocyte counts, length of hospital stay, ICU admission rate, and case-fatality rate. Chest radiographs and laboratory results were reviewed. The presence of bacterial pneumonia was noted. RESULTS: Bacterial pneumonia was diagnosed in 111 hospitalizations (9%): 80 (72%) were community-acquired infections. The CD4+ lymphocyte count was lower (median, 38 vs 66/microL, p = 0.0027), APACHE II score higher (17 vs 13, p < 0. 0001), length of hospital stay longer (median, 6 vs 4), and ICU admission (28% vs 9%) and case-fatality rates (21% vs 4%) higher in patients with bacterial pneumonia compared with those without bacterial pneumonia. The most common pathogen was Pseudomonas aeruginosa (32 admissions), followed by Streptococcus pneumoniae (22 admissions), Staphylococcus aureus (16 admissions), and Haemophilus influenzae (11 admissions). Thirty-three (30%) of the pneumonias were bacteremic. Bacteremia was more common in pneumococcal than in pseudomonal pneumonia (95% vs 9%, p < 0.0001). Compared with patients with pneumococcal pneumonia, patients with pseudomonal pneumonia had lower leukocyte and CD4+ lymphocyte counts, longer hospital stay, and similar case-fatality rate. CONCLUSIONS: P aeruginosa is becoming a common cause of both community-acquired and nosocomial bacterial pneumonia in hospitalized patients with HIV, especially in those with low leukocyte and CD4+ lymphocyte counts.

AIDS-Related Opportunistic Infections↗
PubMed1999

Binding of correolide to K(v)1 family potassium channels. Mapping the domains of high affinity interaction.

Correolide, a novel nortriterpene natural product, potently inhibits the voltage-gated potassium channel, K(v)1.3, and [(3)H]dihydrocorreolide (diTC) binds with high affinity (K(d) approximately 10 nM) to membranes from Chinese hamster ovary cells that express K(v)1.3 (Felix, J. P., Bugianesi, R. M., Schmalhofer, W. A., Borris, R., Goetz, M. A., Hensens, O. D., Bao, J.-M., Kayser, F. , Parsons, W. H., Rupprecht, K., Garcia, M. L., Kaczorowski, G. J., and Slaughter, R. S. (1999) Biochemistry 38, 4922-4930). Mutagenesis studies were used to localize the diTC binding site and to design a high affinity receptor in the diTC-insensitive channel, K(v)3.2. Transferring the pore from K(v)1.3 to K(v)3.2 produces a chimera that binds peptidyl inhibitors of K(v)1.3 with high affinity, but not diTC. Transfer of the S(5) region of K(v)1.3 to K(v)3.2 reconstitutes diTC binding at 4-fold lower affinity as compared with K(v)1.3, whereas transfer of the entire S(5)-S(6) domain results in a normal K(v)1.3 phenotype. Substitutions in S(5)-S(6) of K(v)1.3 with nonconserved residues from K(v)3.2 has identified two positions in S(5) and one in S(6) that cause significant alterations in diTC binding. High affinity diTC binding can be conferred to K(v)3.2 after substitution of these three residues with the corresponding amino acids found in K(v)1.3. These results suggest that lack of sensitivity of K(v)3.2 to diTC is a consequence of the presence of Phe(382) and Ile(387) in S(5), and Met(458) in S(6). Inspection of K(v)1.1-1.6 channels indicates that they all possess identical S(5) and S(6) domains. As expected, diTC binds with high affinity (K(d) values 7-21 nM) to each of these homotetrameric channels. However, the kinetics of binding are fastest with K(v)1.3 and K(v)1.4, suggesting that conformations associated with C-type inactivation will facilitate entry and exit of diTC at its binding site. Taken together, these findings identify K(v)1 channel regions necessary for high affinity diTC binding, as well as, reveal a channel conformation that markedly influences the rate of binding of this ligand.

Amino Acid Sequence↗
PubMed1999

The optimal radiologic method for assessing spinal canal compromise and cord compression in patients with cervical spinal cord injury. Part II: Results of a multicenter study.

STUDY DESIGN: A multicenter, retrospective study using computed tomographic and magnetic resonance imaging data to establish quantitative, reliable criteria of canal compromise and cord compression in patients with cervical spinal cord injury. OBJECTIVES: To develop and validate a radiologic assessment tool of spinal canal compromise and cord compression in cervical spinal cord injury for use in clinical trials. SUMMARY OF BACKGROUND DATA: There are few quantitative, reliable criteria for radiologic measurement of cervical spinal canal compromise or cord compression after acute spinal cord injury. METHODS: The study included 71 patients (55 men, 16 women; mean age, 39.7 +/- 18.7 years) with acute cervical spinal cord injury. Causes of spinal cord injury included motor vehicle accidents (n = 36), falls (n = 20), water-related injuries (n = 8), sports (n = 5), assault (n = 1), and farm accidents (n = 1). Canal compromise was measured on computed tomographic scan and T1- and T2-weighted magnetic resonance imaging, and cord compression at the level of maximum injury was measured on T1- and T2-weighted magnetic resonance imaging. All films were assessed by two independent observers. RESULTS: There was a strong correlation of canal compromise and/or cord compression measurements between axial and midsagittal computed tomography, and between axial and midsagittal T2-weighted magnetic resonance imaging. Spinal canal compromise assessed by computed tomography showed a significant although moderate correlation with spinal cord compression assessed by T1- and T2-weighted magnetic resonance imaging. Virtually all patients with canal compromise of 25% or more on computed tomographic scan had evidence of some degree of cord compression on magnetic resonance imaging, but a large number of patients with less than 25% canal compromise on computed tomographic scan also had evidence on magnetic resonance imaging of cord compression. CONCLUSIONS: In patients with cervical spinal cord injury, the midsagittal T1- and T2-weighted magnetic resonance imaging provides an objective, quantifiable, and reliable assessment of spinal cord compression that cannot be adequately assessed by computed tomography alone.

Adolescent↗
PubMed1999

The biosciences in the pre-registration nursing curriculum: staff and students' perceptions of difficulties and relevance.

This paper considers the problematic position of the biological sciences in pre-registration nurse education--'The Bioscience Question'. There is no consensus and little research on the appropriate content and depth of bioscience knowledge required by nurses. Attempts to apportion curriculum time for the biosciences are confounded by the difficulty experienced by nursing students with this area. Within one university department, a survey was undertaken to investigate the perceptions of pre-registration students, and their teachers, of the teaching and learning of biological science, in comparison with other areas of the curriculum. Our findings concur with others that the biosciences are a source of disproportionate difficulty and anxiety to nursing students. Among the students, but not the lecturers, there was some, by no means universal, support for the suggestion that these problems could be reduced by a reallocation of curriculum time in favour of the biosciences. Although it was agreed that bioscience theory should be related more closely to nursing practice, there was no evidence that this lessened the students' difficulties with the subject. In contrast to lecturers, students felt the biosciences to be one of the areas of the pre-registration curriculum most relevant to clinical practice.

Adaptation, Psychological↗
PubMed1999

Low frequency of CYP2A6 gene polymorphism as revealed by a one-step polymerase chain reaction method.

Human cytochrome P450 2A6 (CYP2A6) has been shown to metabolically activate carcinogens and mutagens. Genetic polymorphisms for CYP2A6 have been reported previously in different ethnic groups using a two-step polymerase chain reaction (PCR) method to identify CYP2A6*1, CYP2A6*2 and CYP2A6*3. Moreover, a new truncated allele has been recently identified in a Japanese population. We report here a one-step PCR amplification of the CYP2A6 gene from human genomic DNA and the detection of intact CYP2A6 alleles by restriction enzyme digestion. The diagnostic exon (exon 3) of the CYP2A6 gene was amplified from human genomic DNA with a primer pair. The forward primer is unique to the CYP2A6 gene, which eliminates previous problems in amplifying two highly homologous CYP2A genes, CYP2A7 and CYP2A13, in humans. The resulting PCR products (214 bp) were digested with XcmI or DdeI to detect the presence of CYP2A6*2 or CYP2A6*3 alleles, respectively. The allelic frequencies for CYP2A6*2 were 2.3% (n = 320) in the Caucasian and 0.7% (n = 71) in the Chinese populations, respectively. CYP2A6*3 allelic frequency in the Chinese population was 0.7%; while no CYP2A6*3 allele was detected in the Caucasian population. The allelic frequencies are relatively low and the reason for this discrepancy between different methods is discussed.

Aryl Hydrocarbon Hydroxylases↗
PubMed1999

Focus on olanzapine.

Olanzapine (2-methyl-4-(4-methyl-1-piperazinyl)-10H-thieno[2,3-b][1,5] benzodiazepine) is a novel antipsychotic agent of the theinobenzodiazepine class developed by Eli Lilly & Co. It has a pleotrophic pharmacology and affects the dopaminergic, serotonergic, muscarinic and adrenergic systems. The therapeutic advantage of recent antipsychotics (so-called atypical antipsychotics) has been attributed to additional serotonergic effects. Clinical studies and trials suggest that olanzapine is comparable or superior to haloperidol and may be superior to risperidone in terms of efficacy and side-effect profiles. The starting dose of olanzapine is a single dose of 10 mg. The drug reaches peak plasma levels in 5-8 h, and has a half-life of about 35 h, depending on metabolism. The recommended maximum dose is 20 mg daily, but higher doses have been employed. Abnormalities of the QTc interval on ECG are unlikely to occur and so there is no need for a baseline ECG as with sertindole, which has recently been withdrawn. The most common side-effects are somnolence and weight gain. About 40% of patients in clinical trials gain weight--especially if they are on a high starting dose and if they were underweight pre-treatment. Reported evidence to date suggests that olanzapine is relatively less likely to produce sexual dysfunction. In general, weight gain and sexual dysfunction are of great concern to people taking antipsychotics and the side-effect profile of any antipsychotic may affect compliance. Olanzapine's general efficacy and side-effect profile suggest that, unforeseen post-marketing complications notwithstanding, olanzapine deserves a major place in the first-line management of psychotic disorders.

Antipsychotic Agents↗
PubMed1999

Focus on quetiapine.

Quetiapine fumarate is a novel dibenzothiazepine antipsychotic developed by Zeneca. It is marketed under the trade name 'Seroquel'. Quetiapine is well tolerated and clinically effective in the treatment of schizophrenia. The initial hope of investigators was that quetiapine would have antipsychotic potential and that it might share some of the properties of clozapine without its toxicity to white blood cells. The effective dosage range is usually 300-450 mg/day split into two doses. The dose is titrated upwards from 25 mg twice daily from day 1 to 300 mg/day on day 4. Elderly patients or patients with liver problems should be started on lower doses. It is both superior to placebo and comparable to haloperidol in reducing positive symptoms at doses ranging from 150 mg/day to 750 mg/day, and is an effective treatment for negative symptoms. Somnolence is the most common adverse event. Abnormalities of the QT interval on ECG appear very infrequently and there is no need for a baseline ECG or blood pressure monitoring, as used to be the case with sertindole. There is no need for haematological monitoring as with clozapine. Quetiapine, across the full dosage range, is associated with no greater extrapyramidal symptoms than placebo. Quetiapine's general efficacy and side-effect profile suggest that, unless there are unforeseen post-marketing complications, it deserves a major place in the initial and long-term management of schizophreniform disorders.

Animals↗
PubMed1999

Long-term followup of the North American multicenter UroLume trial for the treatment of external detrusor-sphincter dyssynergia.

PURPOSE: We determine the long-term efficacy and safety of the UroLume stent as minimally invasive treatment for external detrusor-sphincter dyssynergia in spinal cord injured men. MATERIALS AND METHODS: A total of 160 spinal cord injured men with a mean age plus or minus standard deviation of 36.3 +/- 12.1 years (range 16 to 74) were prospectively treated with an endoprosthesis at 15 centers as part of the North American UroLume trial for external detrusor-sphincter dyssynergia. Urodynamic parameters, including voiding pressure, residual urine volume and bladder capacity, were compared before treatment and at 1, 2, 3, 4 and 5 years after treatment. RESULTS: Mean voiding pressure was 75.1 +/- 28.2 cm. water before treatment in the 160 patients, and 37.4 +/- 23.9 at year 1 in 97, 39.5 +/- 22.2 at year 2 in 84, 42.6 +/- 27.3 at year 3 in 61, 46.3 +/- 33.2 at year 4 in 57 and 44.2 +/- 28.9 cm. at year 5 in 41 after stent insertion (p <0.001). Residual urine volume decreased after stent placement and was maintained throughout the 5-year followup (p <0.001). Mean cystometric capacity remained constant from 269 +/- 155 before insertion to 337 +/- 182 ml. 5 years later (p = 0.17). Hydronephrosis and autonomic dysreflexia improved or stabilized in most patients with functioning stents. Stent explant was necessary in 24 patients (15%), of whom 4 (16.7%) had another stent implanted. CONCLUSIONS: The UroLume stent demonstrates long-term safety and efficacy for the treatment of external detrusor-sphincter dyssynergia. The outcome was similar in men with and without previous sphincterotomy.

Adolescent↗
PubMed1999

Mortality rates after cataract extraction.

Senile cataract may be a marker of generalized tissue aging. We examined this hypothesis using population-based linked health data. We hypothesized that any such association would diminish with increased use of cataract surgery. Mortality rates of those 50-95 years of age undergoing cataract surgery in British Columbia during either 1985 or 1989 were compared with the provincial population of comparable age who did not undergo cataract surgery during the study period. The 1985 cohort included 8,262 patients undergoing surgery and a comparison population of 804,303, and the 1989 cohort included 11,952 patients and a comparison population of 839,393. Using Cox regression, for the 1985 cohort, the hazard ratios for dying during follow-up were 3.2 for males 50-54.9 years of age [95% confidence limits (CL) = 2.0, 5.0] and 3.3 for females (95% CL = 1.9, 5.7). Hazard ratios for older age groups decreased with age. We also fit an additive risk model that produced excess mortalities that were less age dependent. In the 1985 analysis, these ranged from +7.1 per 1,000 (95% CL = +0.44, +13.76) to +20.3 (95% CL = +13.24, +27.36) for males and -17.5 (95% CL = -28.28, -6.72) to +2.0 (95% CL = -2.12, +6.12) for females. Findings for the 1989 analyses were similar, indicating that the association between cataracts and generalized aging remained constant despite a large increase in the use of cataract surgery.

Age Distribution↗
PubMed1998

Giant toads Bufo marinus in Australia and Venezuela have antibodies against 'ranaviruses'.

A serological survey was conducted for antibodies against 'ranaviruses' in the giant toad Bufo marinus in Australia and Venezuela. Sera containing antibodies against 'ranaviruses' were found in both countries. In Australia positive antibodies were identified in populations throughout most of the known range of B. marinus. Results were confirmed by immunofluorescence and immunoelectron microscopy where a characteristic staining pattern of 'ranaviruses' in infected cells was observed. Whilst a 'ranavirus(es)' has been isolated from populations of B. marinus in Venezuela, no virus has been isolated from Australian B. marinus populations. The significance of 'ranavirus' sero-positive B. marinus in Australia is discussed.

Animals↗
PubMed1998

Modulation of the biological functions of galectin-3 by matrix metalloproteinases.

Galectin-3 is an important intracellular and extracellular lectin which is presumed to interact with extracellular matrix proteins and cell surface glycoproteins in normal and pathophysiological conditions. The exact physiological role of the protein is presently not known. We have previously demonstrated that recombinant human galectin-3 is a novel substrate for metalloproteinases, particularly MMP-2 and MMP-9. These enzymes are capable of efficiently cleaving the Ala62-Tyr63 bond of the ca. 30 kDa galectin-3, generating a 22 kDa fragment with intact carbohydrate recognition domain and a ca. 9 kDa polypeptide comprising the amino terminal end of the intact galectin-3. In this study, we analyzed interactions of the 22 kDa fragment of galectin-3 with immobilized laminins. We have also compared the hemagglutination as well as homodimerization potentials of this fragment with that of intact galectin-3. Our data suggest that cleavage of galectin-3 by metalloproteinases; (a) alters the carbohydrate recognition domain of the lectin so that it binds more tightly to the glycoconjugates and, (b) reduces selfassociation of the galectin molecules thereby abrogating the biological properties dependent on such associations or homodimerization.

Animals↗
PubMed1998

Social role functioning by adolescents with psychiatric disorders.

OBJECTIVE: To identify aspects of social role functioning that are impaired in adolescents with specific psychiatric disorders in order to improve the psychiatric taxonomy and clinical knowledge base. METHOD: Adolescents in four urban public schools were screened for mental health problems. Structured psychiatric interviews (National Institute of Mental Health Diagnostic Interview Schedule for Children Version 2.2) with 288 adolescents and their mothers were used to identify youths with psychiatric disorders, and 10 aspects of social role functioning were assessed. Aspects of social role functioning that discriminated between youths with and without psychiatric disorders and between those with emotional disorders and those with disruptive disorders were identified for boys and for girls. RESULTS: Boys with any type of disorder and all youths with disruptive disorders had significant, consistent impairment in academic performance and several other areas of functioning. Youths with emotional disorders, especially girls, demonstrated impairment in social activity participation and peer acceptance, but girls with disorders were not as consistently different from those without as were the boys with emotional disorders. CONCLUSIONS: Role functioning differs in important ways between youths with and without psychiatric disorders and between girls and boys with disorders. The results underscore the importance of investigating observable aspects of role behavior in order to improve the timely detection and effective management of psychiatric disorders in youth.

Adolescent↗