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Biomedical subjects

W D Fisher

Publications and source records attributed to W D Fisher.

At least 19 recordsLinked to original sources
PubMed1989

An evaluation of cognitive-behavioral therapy for training resistance to visually-induced motion sickness.

This investigation examined the techniques for reducing visually-induced motion sickness. On the basis of their responses to a motion sickness history questionnaire, 32 subjects were selected and assigned to 1 of 4 groups such that the groups were matched on the basis of their ability to tolerate visually-induced apparent motion (VM). One group received 10 sessions of desensitization training only (DT); a second group received 10 sessions of cognitive therapy only (CT); a third group received 10 sessions of combined desensitization and cognitive therapy treatment (CG); and a fourth group received no treatment (C). (There are many speculations about why and how an individual's response changes with repeated stimulation. We have arbitrarily selected the term desensitization to connote the decrease in sensitivity over time with repeated exposures). The results indicated that only the groups which received cognitive therapy (i.e., CT and CG) exhibited significant increases in tolerance to VM when pretreatment measures were compared to posttreatment measures. No significant differences in pre- vs. posttreatment measures were observed in the desensitization only or control groups (i.e., DT and C). A similar pattern of results was obtained with the symptomatology data.

Adolescent↗
PubMed1987

Surgical stabilisation of the rheumatoid cervical spine. A review of indications and results.

We have reviewed 32 patients with rheumatoid disease of the cervical spine who underwent a total of 40 operations aimed at correcting instability and improving any associated neurovascular deficit. Apart from four patients with intractable pain, the main indication for surgery was progressive neurological impairment. Of the 32 primary operations, 19 (60%) were successful; the remainder failed to achieve their objective and there were two deaths in the immediate postoperative period. Of eight secondary operations performed for recurrence of symptoms or failure to relieve cervical myelopathy, only four were successful. Of nine operations for bony decompression to relieve cord compression from irreducible subluxation, only four were successful. The overall results show a success rate of 57% and a failure rate of 35% with early operative mortality in 8%. Indications for operation are discussed and earlier diagnosis is considered to be the key to improved results.

Aged↗
PubMed1987

Neer total shoulder replacement in rheumatoid arthritis.

Forty-two shoulders in 37 patients with polyarthritis were treated with Neer total shoulder replacements and reviewed 12 to 66 months afterwards. There was good pain relief and improvement in function, but the range of movement was less than that seen after replacements for osteoarthritis; this may have been related to the fact that 34 shoulders had abnormal rotator cuff tendons. Although there was a high incidence of radiolucent lines around the glenoid component, there was no clinical evidence of loosening. There were a few complications, but on the whole we feel that the Neer total shoulder arthroplasty is a valuable procedure for a patient with polyarthritis.

Adult↗
PubMed1987

Rate of mortality for elderly patients after fracture of the hip in the 1980's.

At an average follow-up of 2.1 years, we reviewed the records of 241 patients who had had a fracture of the hip. The average age of the patients was 75.4 years. The rate of mortality one year after the fracture was 21.6 per cent for the total group, 8.0 per cent for the low-risk group, and 49.4 per cent for the high-risk group. The standard mortality ratio was six times higher for the high-risk group than for the general population (individuals who did not have a fracture), matched for age. It was highest for patients who were less than seventy years old and lowest for those who were older than eighty. However, in the second year after the fracture, the standard mortality ratio approached unity--that is, the rate of mortality approached that of the general population. The results suggest that there is an inverse relationship between mortality and advanced age and that the impact of a fracture of the hip on mortality is seen primarily in the first year after injury.

Adult↗
PubMed1984

Mast cells at sites of cartilage erosion in the rheumatoid joint.

Cartilage-pannus junctions of the rheumatoid lesion have been examined by histochemical and ultrastructural techniques in an attempt to identify the cells responsible for cartilage degradation. Mast cells have been identified at sites of cartilage erosion in 3 specimens of rheumatoid joint. It is known that mast cells participate in immunological reactions, produce the vasoactive and proteinase-modulating agents histamine and heparin as well as their own degradative proteinases. The close association of mast cells with sites of cartilage erosion suggests they may play an important role in the pathophysiology of joint destruction in rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1983

A bacteriologically occlusive clothing system for use in the operating room.

A comparison was made in a laminar-flow operating room between total-body exhaust gowns and a clothing system made from Fabric 450. This disposable clothing was found to be much more comfortable and convenient than the total-body exhaust gowns. The average airborne bacterial counts obtained during total hip replacement operations from each of the clothing systems were identical when the downflow method of ventilation was used (0.7 per cubic metre) and no significant difference could be demonstrated when the crossflow system was used (2.2 per cubic metre with the total-body exhaust gowns and 3.1 per cubic metre with the disposable clothing). Tests in a dispersal chamber were carried out to find the effectiveness of each item of the disposable clothing in reducing bacterial dispersion. These tests demonstrated the relative ineffectiveness of wearing a surgical gown as compared with wearing the complete system. It was confirmed bacteriologically that the downflow system of ventilation was more efficient than the crossflow type; the importance of this observation with respect to clothing and sepsis is discussed in this paper.

Air Microbiology↗
PubMed1982

Stimulation of collagenase secretion from rheumatoid synovial tissue by human collagen peptides.

Dayer et al. demonstrated that mononuclear cells from human peripheral blood produce a mononuclear-cell factor that stimulates collagenase secretion from adherent rheumatoid synovial cells. The production of this mononuclear-cell factor can be stimulated by phytohemagglutinin, a T-cell mitogen. We have examined immune mechanisms by which collagenase secretion may be stimulated from explants of rheumatoid synovial tissue and from primary monolayer cultures of rheumatoid synovial cells. Conditioned media from cultures of normal peripheral-blood mononuclear cells that had been activated by phytohemagglutinin stimulated collagenase secretion from most explants and from all monolayer cultures that were examined. The direct addition of phytohemagglutinin stimulated collagenase secretion in explants from eight of fourteen patients and in monolayer cultures from three of six patients. These observations indicate the presence of responsive T lymphocytes in rheumatoid synovial tissue and implicate them in the stimulation of collagenase secretion from synovial cells. The direct addition of type-II collagen peptides to rheumatoid explants also stimulated collagenase secretion in explants from six to fifteen patients. Four of five of these patients displayed moderate or severe disease activity. Other patients showed a marginal stimulation of collagenase secretion on addition of type-II collagen peptides (four of fifteen patients) and type-I collagen peptides (three of twelve patients). None of the patients with mild or inactive disease responded to type-II collagen. With one exception, the addition of collagen peptides to monolayer cultures did not stimulate collagenase secretion. An increased production of factors that enhance or inhibit the migration of polymorphonuclear leukocytes was also observed in explant cultures in response to the addition of phytohemagglutinin (in seven of twelve patients), of type-I collagen peptides (in five of ten patients), and of type-II collagen peptides (in five of eleven patients). There was no correlation between production of these factors and stimulation of collagenase secretion in rheumatoid synovial tissue.

Arthritis, Rheumatoid↗
PubMed1978

Problems and pitfalls of compression fixation of long bone fractures: a review of results and complications.

The complications encountered in the compression fixation of 70 cortical long bone fractures are reviewed. The results represent the initial experience with the AO fixation equipment following its introduction to a centre with staff relatively untrained in the technique. Infection was the most serious complication, with a deep sepsis rate of 10.5 per cent, but fixation failure, delayed union and refracture also occurred. The various problems are discussed in detail and suggestions are made as to how they can be avoided.

Adolescent↗
PubMed1976

Centrifugal separation of irradiated cultures of Escherichia coli cells into viable and nonviable populations.

Incubation of ultraviolet-irradiated Escherichia coli B/r cultures with 0.7% Triton X-100 resulted in a large decrease in turbidity. Under phase-contrast optics, most of the irradiated detergent-treated cells were smaller than normal and of low phase density; only a small percentage were normal or larger than normal and of normal phase density. Irradiated cells not treated with detergent showed fewer pronounced morphological changes. Irradiated cells treated with detergent lost large amounts of proteins and ribonucleic acid, but not of deoxyribonucleic acid. Such cultures could be separated by centrifugation into populations of (i) slowly sedimenting cells consisting of small, phase-light cells of low viability and (ii) large cells of normal phase density and high viability (100%). A similar separation was effected in gamma-irradiated cultures.

Bacterial Proteins↗
PubMed1976

Pyrimidine dimer excision in surviving and nonsurviving cells of ultraviolet-irradiated cultures of Escherichia coli.

We compared dimer excision in viable and nonviable cells fractions separated from Escherichia coli B/r cultures exposed to ultraviolet (UV) irradiation. For cells grown on minimal medium with glycerol as a carbon source, both fractions from the irradiated (20 J/m2, 5% survival) culture excised 60 to 70% of the thymine dimers from prelabeled DNA within 120 min. This percentage was, within experimental error, the same as that obtained from unseparated cultures. When isolated viable and nonviable populations were given a second UV exposure (20 J/m2) both types of cells were again able to excise dimers. The UV survival curve for the isolated viable population indicates that these cells are no more sensitive to radiation than exponentially growing cells not previously exposed to UV. The extent of dimer excision after UV irradiation was also the same in viable and nonviable cells separated from cultures grown on a glucose minimal medium in which both populations excised about 85% of the dimers within 120 min. These results show that the extent of removal of pyrimidine dimer from deoxyribonucleic acid is not precisely correlated with survival of repair-competent bacterial cells after exposure to UV light.

DNA Repair↗
PubMed1973

Mechanism for the regulation of cell division in Agmenellum.

We describe a nonlethal temperature-conditional mutant of Agmenellum quadruplicatum which allows dissociation of the processes of growth and cell division. With this system, evidence has been obtained for the regulation of one step in the process of cell division by a small effector molecule. The effector molecule is apparently released into the surrounding medium and can be obtained from lyophilized spent medium by extraction with 80% ethanol. The addition of this extract to serpentine filaments of the SN29 mutant strain stimulates cell division in these filaments and leads to the production of cells approximating normal dimensions within one generation time. The degree of stimulation of cell division is directly related to the amount of extract added. A general hypothesis is presented for the positive regulation of the initiation of cell wall and cell membrane invagination in this organism.

Bacteria↗
PubMed1973

Novel mutant impaired in cell division: evidence for a positive regulating factor.

A novel, conditional, cell-division mutant from Agmenellum quadruplicatum strain BG1 is described. During rapid growth in dilute suspensions, cell division lags behind mass increase and the cells form filaments. These filaments spontaneously divide into unit cell lengths as the culture density increases. Other conditions that favor the accumulation of metabolic products in the medium antagonize filament formations. An 80% ethanol-water extract of dried, spent medium also restores the ability of filaments to divide into cells of unit length. Our results suggest that at least one chemical factor acting as a positive effector is involved in cell division.

Bacteriological Techniques↗