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Biomedical subjects

T Banks

Publications and source records attributed to T Banks.

At least 37 records · Page 2Linked to original sources

Examination of recombinant truncated mature human fibroblast collagenase by mass spectrometry: identification of differences with the published sequence and determination of stable isotope incorporation.

Human fibroblast collagenase belongs to a family of matrix metalloproteinases which have been implicated in a number of connective tissue disorders ranging from rheumatoid arthritis to tumor invasion. To examine the active site of this enzyme by biophysical studies, a 19 kDa recombinant truncated mature collagenase (mCL-t) was prepared. Electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry have been utilized for the characterization of mCL-t. The molecular weights measured by these techniques identified the presence of two closely related protein components separated by approximately 100 Da. Edman sequence analysis demonstrated that the two protein components differ from each other by an amino terminal valine, consistent with the mass spectrometric data. In addition, the molecular weight of mCL-t determined by mass spectrometry did not agree with that calculated from the reported sequence. To identify the origin of this discrepancy, the DNA sequence of the mCL-t clone was examined. Several differences were noted between the DNA sequence of mCL-t and the published collagenase gene sequence. When these differences were taken into account, the measured molecular weights were found to be in good agreement with that calculated for the modified sequence. In separate experiments, both ESI and MALDI mass spectrometry have been used to determine molecular weights of mCL-t samples enriched with stable isotopes 15N and (15N + 13C). The measured molecular weights demonstrated a 97% (15N) and 99% (15N + 13C) incorporation of labeled isotopes in the two samples.

Amino Acid Sequence↗

Dental surgery assistants' roles in cross-infection control in general dental practice: their knowledge and use of autoclaves.

This study investigated dental surgery assistants' (DSAs) role in providing cross-infection control in general dental practice. DSAs' knowledge about using autoclaves and their compliance with the recommended procedures were used as measures. Eighty-nine practices in three districts of the North Western Region of England were approached. Fifty-six agreed to permit the study and DSAs in these practices were observed at work and questioned, a response rate of 63%. Eighteen tasks relating to use of autoclaves (eg correct loading of instruments and correct storage) were observed and knowledge about them was assessed by questioning. Each was scored positively if correctly undertaken and answered. Scores for compliance varied between 2 and 12 and between 3 and 15 in the case of knowledge. In all instances certificated DSAs scored more highly than uncertificated DSAs. The study illustrated the value of certification, background education and membership of a vocational organisation. It supports the belief that all DSAs should be educated to the level of certification and that this improved education and training would improve cross-infection control in general dental practice.

Certification↗

Gene transfer to freshly isolated human respiratory epithelial cells in vitro using a replication-deficient adenovirus containing the human cystic fibrosis transmembrane conductance regulator cDNA.

Cystic fibrosis (CF) results from mutations of the CF transmembrane conductance regulator (CFTR) gene and subsequent defective regulation of cAMP-stimulated chloride (Cl-) permeability across the apical membrane of epithelial cells. In vitro transfer of normal CFTR cDNA corrects this defect, and studies in experimental animals have shown successful gene transfer to airway epithelium in vivo using a recombinant adenoviral vector containing the human CFTR cDNA (AdCFTR), supporting the feasibility of in vivo AdCFTR-mediated gene therapy for the respiratory manifestations of CF. One step in applying this therapy to CF patients is to evaluate the safety and efficacy of AdCFTR-mediated gene transfer in the actual target for human gene therapy, human airway epithelium. The present study demonstrates that AdCFTR restores cAMP-stimulated Cl- permeability in human CF bronchial epithelial cells. In addition, the study utilizes freshly isolated human airway epithelial cells from the nose and/or bronchi of normal individuals and/or individuals with CF to demonstrate that after in vitro AdCFTR-mediated gene transfer: (i) AdCFTR DNA does not replicate as a function of dose and time; (ii) CF epithelial cells express AdCFTR-mediated normal human CFTR mRNA; and (iii) CF epithelial cells, including terminally differentiated ciliated cells (the most common airway epithelial cell type), express the normal human CFTR protein. Together, these data support the use of AdCFTR in human gene therapy trials and suggest that biologic efficacy should be achievable in vivo.

Adenoviridae↗

A difficult combination.

The case of a 34 year old man with chronic severe asthma and schizophrenia has been described. Attempts at treating his conditions have not met with success. Optimal management of one problem is precluded by the other. There is a possibility that aggressive management will do more harm than good.

Adult↗

Diversity in junctional sequences associated with the common human V gamma 9 and V delta 2 gene segments in normal blood and lung compared with the limited diversity in a granulomatous disease.

The T cell receptor (TCR) junctional regions (N regions) of the common human V gamma 9 and V delta 2 gene segments were sequenced from the blood and lung of normal individuals (195 transcripts) and a group of individuals with sarcoidosis (220 transcripts), a granulomatous disease in which increased numbers of V gamma 9+ gamma/delta + T cells are often observed. In normal individuals, the vast majority (86%) of blood V gamma 9 transcripts used the J gamma P gene segment. In contrast to this restriction of J region usage, there was a large diversity of the junctional region, with less than 20% of blood V gamma 9 junctional regions showing identical sequences for any one normal individual. For the blood V delta 2 transcripts in normal individuals, there was restriction of J region usage, with 93% using J delta 1. The junctional regions were even more diverse than for V gamma 9, with a unique sequence observed in each transcript examined. Compared with blood, sequences from the normal lung showed a small increase in identical junctional regions, particularly in one individual where 46% of V gamma 9 transcripts examined were identical, suggesting a response of some gamma/delta T cells to antigens found in the lung in the normal state. In marked contrast to normals, some individuals with sarcoidosis had large numbers of V gamma 9 transcripts, as well as V delta 2 transcripts, sharing identical sequences. For V gamma 9 blood transcripts, two individuals showed 84 and 56% of junctional region sequences to be identical, respectively. Similarly, blood V delta 2 transcripts showed 43, 33, and 25% identical junctional region sequences in three individuals. In the sarcoid patient with the most striking over-representation of blood V gamma 9 junctional sequences, lung V gamma 9 transcripts showed increased (67%) use of the same junctional region sequence as in blood. This limited diversity of TCR junctional regions among some individuals with sarcoidosis suggests a response from specific stimuli, possibly antigenic, and that gamma/delta T cells may play a specific role in granuloma formation in sarcoidosis, as has been suggested in other granulomatous diseases.

Adult↗

Domain structure of herpes simplex virus 1 glycoprotein B: neutralizing epitopes map in regions of continuous and discontinuous residues.

Herpes simplex virus 1 (HSV-1) glycoprotein B (gB) is a multifunctional glycoprotein required for infectivity; it is thought to promote fusion of the viral envelope with the cell membrane and entry of virions into cells. To map the antigenic and functional domains on gB, we constructed amino terminal derivatives lacking the entire carboxyl terminus and internal deletion mutants lacking defined regions of the extracellular and transmembrane domains. Transient expression of the mutants in COS-1 cells revealed that the amino terminal derivatives were released into the medium whereas those with deletions in the extracellular domain were mostly retained within the transfected cells. Analysis of intact gB and the amino terminal derivatives showed that the intact molecule formed dimers whereas the mutant derivatives did not. Reactions of the derivatives with a panel of well-characterized monoclonal antibodies to gB showed that the neutralizing epitopes cluster in two domains. The first maps in the amino terminal 190 residues and contains seven continuous epitopes, five of which are HSV-1-specific. Reactions of antibodies with a set of oligopeptides fine-mapped the epitopes between residues 1 and 47. The second domain is composed of discontinuous epitopes and was expressed by amino terminal derivatives that were at least 457 residues in length or longer. Eleven epitopes map in this region, including those of four potent neutralizing antibodies whose cognitive sites mapped between residues 273 and 298 in mapping studies using antibody-resistant mutants. Results of the present study indicate that the cognitive sites of these antibodies are assembled into the discontinuous domain by juxtaposing residues from the amino-terminal half of gB monomers.

Amino Acid Sequence↗

A major neutralizing domain maps within the carboxyl-terminal half of the cleaved cytomegalovirus B glycoprotein.

Cytomegalovirus (CMV) encodes several glycoproteins reported to be structural homologues of glycoproteins encoded by herpes simplex virus type 1 (HSV-1). To map the antigenic and functional domains on the 907 amino acid CMV glycoprotein B (gB), we cloned and expressed a subfragment of BamHI fragment R of the CMV (Towne) genome into an expression vector and reacted the resulting gene product with a panel of monoclonal antibodies. Our results showed that the DNA fragment encodes related glycoproteins which we previously designated gA and which others have reported to be homologous to HSV-1 gB in CMV (AD169). Analyses of the processing of CMV gB transiently expressed in eukaryotic cells showed that glycosylation occurred independently of viral infection. Ten antibodies with complement-dependent and independent neutralizing activity reacted with a truncated derivative of gB that contained 619 amino-terminal residues but lacked the transmembrane and intracellular regions of the molecule. Twelve additional antibodies reacted with a CHO cell line expressing a 680 amino-terminal derivative of gB. All of the reactive antibodies precipitated the 447 residue carboxy-terminal cleavage product of gB from extracts of CMV-infected cells. These results showed that the neutralizing epitopes map in at least two domains of gB which are located in a discontinuous segment of 219 amino acids between residues 461 and 680 from the amino terminus of the molecule.

Cytomegalovirus↗

Dietary management of the patient with atherosclerosis: are the new National Cholesterol Education Panel recommendations enough?

The black patient has a poorer prognosis with arteriosclerotic heart disease than does a white patient and needs a more aggressive approach to reduce cholesterol and other risk factors. The new National Cholesterol Education Panel recommendations are similar to those used in the Multiple Risk Factor Intervention Trial study which lowered cholesterol levels only by 5% to 7% over a seven-year period. We recommend a more aggressive dietary approach introducing the postinfarction patient to a less than 10% fat and 50 mg cholesterol vegetarian diet while recovering in the hospital.

Arteriosclerosis↗

Pneumoperitoneum associated with mechanical ventilation.

The true incidence of pneumoperitoneum associated with mechanical ventilation is unknown, but current estimates range from rare to 7 percent of intubated intensive care unit patients. This syndrome should be strongly suspected when pneumoperitoneum develops in a mechanically ventilated patient with a combination of (1) peak inspiratory pressure (PIP) greater than 40 cm H(2)O; (2) positive end expiratory pressure (PEEP) greater than 6 cm H(2)O; and (3) coexistent evidence of significant pulmonary barotrauma. An illustrative case report is presented where this entity was recognized and the patient managed without laparotomy. Controlled prospective studies should determine the true importance of this problem.

Adolescent↗