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Biomedical subjects

J W Bell

Publications and source records attributed to J W Bell.

At least 19 recordsLinked to original sources
PubMed1988

Porphyrin induced Z to B conversion of poly(dG-dC)2 in ethanol.

The water soluble porphyrins H2TMpyP-2, H2TMpyP-4, and CuTMpyP-4 are found to bind to Z-form poly(dG-dC)2 in 60% ethanol (v/v) and to facilitate the conversion of the polymer to the B form. Metalloporphyrins with axial ligands (MnTMpyP-4, ZnTMpyP-4) interact to some degree with the Z form, but do not lead to extensive conversion to the B form. The conversion of the Z form into the B form was determined by CD titration experiments, which were used to quantitate the fraction of poly(dG-dC)2 present in each conformation. Under all conditions each bound porphyrin molecule converts multiple base pairs from Z to B. The kinetics of porphyrin reactions with Z-poly(dG-dC)2 in 60% ethanol were measured using two different detection techniques. Stopped flow spectrophotometry was used to observe the time-dependent spectral changes associated with the porphyrins during the reaction. Time-dependent changes in the poly(dG-dC)2 conformation were observed directly using CD. The porphyrin absorbance changes under the conditions of these experiments have a much shorter half time (t1/2 approximately 0.1 to 2 sec) than the CD changes (t1/2 approximately 10 sec). Thus it could be determined that a complex with spectral characteristics similar to those of the porphyrin intercalated into B-form poly(dG-dC)2 is produced while the polymer is predominantly in the Z form.

Circular Dichroism↗
PubMed1985

Temporomandibular joint dysfunction syndrome. A clinical report.

We have presented two clinical case reports of patients with TMJ dysfunction syndrome as an example of coordinated treatments between dentists and physical therapists. The clinical profiles of these patients with craniocervical pain were compiled from comprehensive physical therapy and dental-orthopedic evaluations. The significance of the relationship between the rest position of the mandible and forward head posture has been shown by the changes observed after correction of the postural deviations and vertical resting dimensions by dental treatments and physical therapy. Additional research is necessary to determine long-term effects of this combined approach in TMJ dysfunction syndrome.

Adult↗
PubMed1980

Surgical case review: rationale and methods.

Review of all surgical cases is necessary to ensure the proper utilization of surgical treatment. The review process may be simplified by the adoption of indicator criteria which can be used by a designated individual (in some instances, a nonphysician) to screen cases. When carried out carefully and critically, this type of screening surveillance should yield those cases that warrant a serious review by the committee and thus can afford reasonable assurance that surgical services are utilized appropriately. Because the use of indicator criteria to screen procedures for which surgical indications are still evolutionary and controversial may be unwise and unduly provocative, a policy of individual case review should probably be retained for these cases.

Humans↗
PubMed1978

Serotyping herpes simplex virus isolated by enzyme-linked immunosorbent assays.

An enzyme-linked immunosorbent assay (ELISA) using a double-antibody sandwich tecnhique has been developed to serotype isolates of herpes simplex virus from clinical sources. The results obtained using this procedure were in agreement with those obtained with a standard neutralization test in typing stock cultures and 32 clinical isolates of herpes simplex virus. Clear differentiation between the two viral serotypes was obtained using rabbit immunoglobulin cross-absorbed with heterologous virus antigen. The ELISA procedure described appears to be a convenient and accurate substitute for the neutralization test in typing herpes simplex viruses. ELISA techniques require relatively small amounts of antigen and antibody and can be performed with very simple equipment.

Enzyme-Linked Immunosorbent Assay↗
PubMed1978

Effect of low-NaCl medium on the envelope glycoproteins of Sindbis virus.

Lowering the NaCl concentration of the medium inhibits the release of Sindbis virus from infected chicks cells at a stage after the nucleocapsids have bound to the membranes of the infected cells. The failure of trypsin treatment to release the inhibited virus and the ratio of the proteins in the inhibited cells make it seem likely that the inhibited virus is all intracellular. Experiments using antisera specific for E1 and E2, the envelope glycoproteins of Sindbis, suggest that the inhibitory effect of low-salt medium is mediated through an effect on E2. Lactoperoxidase radioiodination experiments indicate that, even when cleaved from PE2, E2 is not exposed on the surface of low-NaCl-treated chick cells.

Cell Line↗
PubMed1977

Envelope antigens of Sindbis virus in cells infected with temperature-sensitive mutants.

Indirect fluorescent-antibody studies of living and fixed chick cells infected with temperature-sensitive mutants of Sindbis virus suggest that functional envelope glycoprotein E1 must be inserted through the plasma membrane before E2. PE2 and E2 do not affect the insertion of E1. The experiments also suggest that normal PE2, a glycosylated precursor to E2, reacts with anti-E2 serum; the abnormal PE2 made by a temperature-sensitive PE2 cleavage-defective mutant did not. Abnormal E1 proteins made by E1-defective mutants also failed to react with anti-E1 serum.

Antigens, Viral↗
PubMed1974

Menopausal flushing: double-blind trial of a non-hormonal medication.

A multicentre, placebo-controlled, double-blind, cross-over study conducted in general practice on 100 patients has shown clonidine to have a statistically highly significant effect in controlling the number and the severity and duration of menopausal flushes. The relatively mild side effects and the absence of potentially harmful oestrogenic effects suggest that clonidine in the dose range 25 to 75 mug twice daily is a useful addition or alternative to the existing therapy for this common symptom of the menopause.

Adult↗