Search PubMed⌕ Search

Biomedical subjects

T F Smith

Publications and source records attributed to T F Smith.

At least 199 records · Page 11Linked to original sources
PubMed1987

Possible origin of a calmodulin gene that lacks intervening sequences.

The divergent, muscle-specific allele of the chicken calmodulin gene contains no intervening sequences and apparently was produced by a reverse transcriptase-mediated event. The nucleotide and deduced amino acid sequences of this gene were compared with nucleotide and amino acid sequence data of other known calmodulin genes in order to investigate its evolutionary history. These comparisons, as well as the CpG dinucleotide content, support the conclusion that this highly divergent chicken calmodulin gene did not exist for any significant period of times as a pseudogene and suggest plausible alternative genetic histories. The most parsimonious history involves the viral import of a very old foreign gene of high CpG content.

Amino Acid Sequence↗
PubMed1987

Evaluation of Cytomegelisa immunoglobulin M assay and comparison with indirect fluorescent antibody testing of QAE-Sephadex A50-treated sera.

The Cytomegelisa IgM assay (M. A. Bioproducts, Walkersville, MD) was evaluated as an alternative to indirect fluorescent antibody (IFA) testing of QAE-Sephadex A50-treated sera for detection of cytomegalovirus (CMV)-specific IgM. The Cytomegelisa assay was consistently more sensitive than IFA testing for detection of CMV-specific IgM. Of 101 rheumatoid factor-negative sera that were IFA positive before column separation, only 47 (46%) remained positive after column separation, while 72 (71%) were positive using Cytomegelisa. Nine transplant patients who had primary CMV infection develop were also evaluated. Two of the nine did not form sufficient IgM to remain IFA positive after column separation, however, all had IgM detected by Cytomegelisa. In all cases, Cytomegelisa provided laboratory evidence of CMV infection earlier or at the same time as IgG seroconversion or IgM testing by column/IFA. Comparison of both methods with 100 consecutive sera received for CMV testing yielded five sera positive for CMV-IgM with the column/IFA method and 20 using Cytomegelisa. The specificity of Cytomegelisa was evaluated with 56 RF-positive/CMV IgG-positive sera. Four of 56 (7%) appeared positive after column separation; however, of concern, 22 of 56 (39%) remained positive in the Cytomegelisa.

Antibodies, Viral↗
PubMed1987

The effect of centrifugation on the rapid detection of adenovirus in shell vials.

Monoclonal antibody, specific for the adenovirus group-reactive hexon antigen, was used for the detection of this agent by immunofluorescence 24 and 48 hours after inoculation of HEp-2 cell monolayers in 1-dram shell vials after low-speed centrifugation (700 X g, 30 minutes). Of 31 adenovirus isolates, 16 (sensitivity, 52%) and 30 (sensitivity, 97%) were detected after incubation for 24 hours and 48 hours, respectively. All adenovirus strains were detected in conventional tube cell cultures but required an average of four days incubation. The shell vial assay is rapid, sensitive, and specific and can be easily implemented in laboratories with cell culture experience.

Adenoviruses, Human↗
PubMed1987

Molecular genetics and computer analyses.

This issue of CABIOS contains a set of reviewed papers which relate to the recent Macromolecules, Genes and Computers International Workshop and Symposium held August 12-17, 1986 in Waterville Valley, NH. This introductory article reviews that meeting and those ideas which will provide a useful context for the continuing research and discussions on molecular genetic analyses contained within this issue.

Amino Acid Sequence↗
PubMed1987

A modified Chou and Fasman protein structure algorithm.

A FORTRAN program PRSTRC has been developed for protein secondary structure prediction, which is a modified Chou and Fasman (1978) analysis. This implementation carries out a running average of amino acid structure occurrence frequencies, utilizes a simple set of nucleation conditions, and allows user control over nucleation threshold and cutoff parameters. The algorithm includes prediction of the newly defined secondary structure elements: omega loops (1986). It also generates a charge distribution and hydropathy profile. Output includes a simple graphic display for a printer, or a CRT using color addition. Correct structures are predicted for T. dyscritum hemerythrin and the variable domain of mouse immunoglobin k-chain.

Algorithms↗
PubMed1987

Recognition of characteristic patterns in sets of functionally equivalent DNA sequences.

An algorithm has been developed for the identification of unknown patterns which are distinctive for a set of short DNA sequences believed to be functionally equivalent. A pattern is defined as being a string, containing fully or partially specified nucleotides at each position of the string. The advantage of this 'vague' definition of the pattern is that it imposes minimum constraints on the characterization of patterns. A new feature of the approach developed here is that it allows a 'fair' simultaneous testing of patterns of all degrees of degeneracy. This analysis is based on an evaluation of inhomogeneity in the empirical occurrence distribution of any such pattern within a set of sequences. The use of the nonparametric kernel density estimation of Parzen allows one to assess small disturbances among the sequence alignments. The method also makes it possible to identify sequence subsets with different characteristic patterns. This algorithm was implemented in the analysis of patterns characteristic of sets of promoters, terminators and splice junction sequences. The results are compared with those obtained by other methods.

Algorithms↗
PubMed1987

Detection of cytomegalovirus infections in specimens other than urine by the shell vial assay and conventional tube cell cultures.

Blood, bronchoscopy-lavage, biopsy (lung, liver, kidney), sputum, and other (cecum, bone) specimens were inoculated into shell vials and conventional cell tube cultures seeded with MRC-5 cells over a 23-month period. Of 1,472 specimens, 182 (12.4%) yielded cytomegalovirus (CMV)-positive results from 81 patients. Significantly more CMV-positive specimens were detected in shell vials (n = 154; 84.6%) than in conventional tube cell cultures (n = 126; 69.2%) (P less than 0.01). We found that 98 (53.8%) of the total 182 and 41 (42.7%) of the 96 blood specimens positive for CMV were detected by both the shell vial assay and conventional tube cell cultures. However, 56 (30.7%) of the total 182 and 31 (32.3%) of the 96 blood specimens positive for CMV were obtained exclusively in shell vials after detection with monoclonal antibody. Alternatively, 28 (15.4%) of the total 182 and 24 (25%) of the 96 blood specimens positive for the virus were isolated only in conventional tube cell cultures. Thus, although the shell vial assay was more sensitive and rapid than the conventional tube cell culture method, both systems must be used, especially for blood specimens, for the laboratory diagnosis of CMV infections.

Antigens, Viral↗
PubMed1987

Simultaneous seeding and infecting of shell vials for rapid detection of cytomegalovirus infection.

Fifty cytomegalovirus isolates were used to infect shell vials containing confluent MRC-5 cell monolayers and shell vials which were seeded with MRC-5 cells at the time of inoculation. All 50 of the isolates were detected by immunofluorescence in shell vials containing confluent monolayers, whereas 39 (78%) of the isolates were detected in shell vials that had been seeded and inoculated simultaneously (P less than 0.001). Preformed monolayers of cells in shell vials provide the most sensitive system for the detection of cytomegalovirus infection.

Cell Line↗
PubMed1987

Cutaneous mastocytosis with bleeding: probable heparin effect.

We describe here a child with diffuse cutaneous mastocytosis whose early clinical course was complicated by recurrent episodes of severe gastrointestinal bleeding. These episodes were preceded by formation of cutaneous bullae and were associated with prolonged coagulation times. In the child reported here, it is likely that the degranulation of mast cells in the skin resulted in gastrointestinal bleeding by the dual actions of heparin producing anticoagulation and histamine producing increased vascular permeability. It is possible that our patient's symptoms were related both to increased number of mast cells and increased releasability of mediators from these cells; his clinical course suggested that an alteration of the latter occurred spontaneously over time.

Gastrointestinal Hemorrhage↗
PubMed1987

Allergy and pseudoallergy: an overview of basic mechanisms.

Immediate hypersensitivity reactions are complex; they involve many cells and many mediators. Appropriate therapy of allergic diseases depends on an understanding of these cells and mediators. This article describes cells involved, discusses current concepts of cell triggering, and reviews mediators involved in immediate hypersensitivity reactions.

Animals↗
PubMed1986

The molecular biology computer research resource.

Described is a new National Institutes of Health supported Molecular Biology Computer Research Resource located at the Dana-Farber Cancer Institute in association with Harvard University, Boston, Massachusetts.

Animals↗
PubMed1986

A unique element resembling a processed pseudogene.

We describe a unique DNA element with structural features of a processed pseudogene but with important differences. It is located within an 8.4-kilobase pair region of chicken DNA containing five histone genes, but it is not related to these genes. The presence of terminal repeats, an open reading frame (and stop codon), polyadenylation/processing signal, and a poly(A) rich region about 20 bases 3' to this, together with a lack of 5' promoter motifs all suggest a processed pseudogene. However, no parent gene can be detected in the genome by Southern blotting experiments and, in addition, codon boundary values and mid-base correlations are not consistent with a protein coding region of a eukaryotic gene. The element was detected in DNA from different chickens and in peafowl, but not in quail, pheasant, or turkey.

Amino Acid Sequence↗
PubMed1986

Aneurysmal subarachnoid hemorrhage and viral infection. Lack of association.

We tested the hypothesis that intracranial aneurysm develops because of viral infection that produces arterial damage, and that aneurysmal rupture is related to viral infection. The following viral agents were studied: influenza A, influenza B, and respiratory syncytial viral titers, by the indirect immunofluorescence method, in 29 patients and 29 controls; herpes simplex virus titers, by immunofluorescence, in 31 patients and 31 controls; rubella viral titers (Rubazyme test), in 34 patients and 34 controls; and influenza A and B viral titers, by the complement fixation method, in 54 patients and 54 controls. Patients were selected on the basis of documented aneurysmal subarachnoid hemorrhage. Analysis, with derivation of the chi 2 method, to compare titer levels in patients and controls for each specific viral titer did not reveal positive correlations between the viral titers and aneurysmal subarachnoid hemorrhage.

Adolescent↗
PubMed1986

Echovirus polymyositis in patients with hypogammaglobulinemia. Failure of high-dose intravenous gammaglobulin therapy and review of the literature.

A 29-year-old man with X-linked hypogammaglobulinemia was treated with prednisone and methotrexate for polymyositis. Subsequently, it was established that disseminated echovirus 11 infection was causing the polymyositis. Treatment with large doses of intravenous gammaglobulin did not result in improvement. Viral cultures of blood, urine, and cerebrospinal fluid gave positive results throughout treatment and at postmortem examination. Multiple cultures of other tissues, including muscle, also gave positive results at postmortem examination. Severity of infection and treatment with prednisone and methotrexate prior to referral, diagnosis, and gammaglobulin treatment may explain the lack of response. A review of 23 cases of echovirus infection in patients with hypogammaglobulinemia revealed that the infection in these patients may cause meningoencephalitis or a polymyositis-like syndrome or both. Treatment with immunosuppressive agents, the standard therapy for polymyositis, is contraindicated, and intravenous or intraventricular gammaglobulin or both may be helpful.

Adolescent↗
PubMed1986

Comparison of culture, cytotoxicity assays, and enzyme-linked immunosorbent assay for toxin A and toxin B in the diagnosis of Clostridium difficile-related enteric disease.

Clostridium difficile culture, test tube, and microtiter cytotoxicity assays, and enzyme-linked immunosorbent assays (ELISAs) for toxin A and toxin B, were simultaneously performed on 113 fresh diarrheal stool specimens randomly selected from those submitted to our clinical laboratory for routine C. difficile testing. The performance of these tests in diagnosing C. difficile-related enteric disease (CDRED) was based on a clinical assessment of the likelihood of CDRED as determined by a systematic review of case histories blinded from the test results. Among 61 antibiotic recipients, both the microtiter cytotoxicity assay and the toxin A ELISA were highly specific for CDRED (95% and 100%, respectively). Specificities for the other procedures were much lower (tube cytotoxicity assay, 79%; culture, 74%; and toxin B ELISA, 56%). The high sensitivities of the culture (89%) and toxin B ELISA (83%) were somewhat negated by their low specificities. The only test that was both specific and had acceptable sensitivity (78%) was the microtiter cytotoxicity assay. This study indicates that ELISAs for detection of C. difficile toxins are not as reliable as the cytotoxicity assay in the laboratory diagnosis of CDRED, and that clinical correlation is essential in the evaluation of any new test for CDRED.

Adult↗