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Biomedical subjects

D H Wilson

Publications and source records attributed to D H Wilson.

At least 55 records · Page 3Linked to original sources
PubMed1991

Predictors of functional outcome and resource utilization in inpatient rehabilitation.

Consecutive patients (n = 1,289) discharged from two inpatient rehabilitation facilities were prospectively examined to determine the extent to which rehabilitative outcomes, functionally based progress, and associated resource utilization (in terms of rehabilitation length of stay) can be concomitantly predicted using the Tufts/New England Medical Center functional assessment tool and bivariate and multivariate statistical comparisons. A high percentage (greater than 50%) of statistically significant associations between the predictor variables and seven outcome measures were seen. The R2s corresponding to these associations were generally small and resistant to enhancement by commonly accepted statistical manipulations. Consequently, they are, in general, of limited predictive value for determining functional prognosis or resource utilization among rehabilitation inpatients. Although functionally based predictors appear to be the best predictors of functional progress, their effectiveness as predictors of other domains (eg, discharge outcome and rehabilitation length of stay) is variable. The implication is that a prospective payment system using such an array of predictors and directed primarily at cost containment is likely to overlook potentially important gains in functional progress and patient outcome. Furthermore, the functionally based predictors, taken individually, varied in effectiveness as predictors among facilities, and, taken collectively, they varied in effectiveness as predictors for different diagnostic groupings within a facility. The inconsistency of predictions according to the various domains appears to further limit their application to a prospective payment model.

Activities of Daily Living↗
PubMed1990

"Sick of Smoking": evaluation of a targeted minimal smoking cessation intervention in general practice.

Several smoking intervention studies have been conducted overseas which use a minimal amount of general practitioners' time and are conducted within the constraints of a normal consultation. However, there are no published reports of minimal interventions in Australian general practice. This study reports on 1238 South Australian smokers who were assigned to a non-intervention control group or a group which received firm general practitioner advice to quit smoking plus literature. At one-year follow-up, 7.5% of smokers in the minimal advice group who had quit for six or more months remained non-smokers compared with 3.2% in the control group. If similar analytical procedures had been used in this study as were used in the benchmark study in England in 1979, the quit rate for this study would have been 11.3% in the intervention group, and 4.8% in the control group--a net gain of 6.5%. These results are discussed with regard to widespread implementation in Australian general practice.

Adolescent↗
PubMed1990

Kinetic analysis of the pre-equilibrium steps in the self-assembly of RecA protein from Escherichia coli.

Total intensity light scattering is employed to investigate the self-assembly kinetics of RecA protein. Reaction conditions are employed where the kinetics of self-assembly are slow enough to yield reliable scattered intensity measurements over the range of scattering angles from 40 to 130 degrees as a function of time. From these measurements the time-dependent behavior of the weight average molecular weight, Mr, and radius of gyration, RG, of the associating protein species as a function of [MgCl2], [NaCl], [RecA], and pH was determined. The temperature dependence of RecA self-assembly was also investigated and allowed an evaluation of the activation thermodynamic parameters of association. Results reveal RecA self-assembly is bi-phasic under all conditions examined. The first phase, referred to as "filamentation" is second-order in [RecA] and occurs via a quasi linear condensation scheme with an Arrhenius activation energy of 88.6 kcal/mol. Filamentation assembly involves the uptake of one proton, one MgCl2, the release of five to six NaCls, and is driven by the release of approximately 70 water molecules. The evaluated activation parameters of the first kinetic phase are consistent with the proposition that linear self-assembly of RecA protein into ordered filaments is entropically driven. The second kinetic phase, referred to as "bundling" is greater than second-order in both [RecA] and [MgCl2], is considerably slower that filamentation assembly, and is apparently initiated by 2nd order collisions of linear filaments.

Escherichia coli↗
PubMed1990

Structure and dynamics of M13mp19 circular single-strand DNA: effects of ionic strength.

Dynamic and static light scattering, CD, and optical melting experiments have been conducted on M13mp19 viral circular single-strand DNA as a function of NaCl concentration. Over the 10,000-fold range in concentration from 100 microM to 1.0 M NaCl, the melting curves and CD spectra indicate an increase in base stacking and stability of stacked regions with increased salt concentration. Analysis of dynamic light scattering measurements of the single-strand DNA solutions as a function of K2 from 1.56 to 20 X 10(10) cm-2 indicates the collected autocorrelation functions are biexponential, thus revealing the presence of two decaying dynamic components. These components are taken to correspond to (1) global translational motions of the molecular center of mass and (2) motions of the internal molecular subunits. From the evaluated relaxation rates of these components, diffusion coefficients D0 and Dplat are determined. The center of mass translational diffusion coefficient D0, varies in a nonmonotonic manner, by 10%, from 3.75 X 10(-8) to 3.39 X 10(-8) cm2/s over the NaCl concentration range from 100 microM to 1.0 M. Likewise, the radius of gyration RG, obtained from static light scattering experiments, varies by 15% from 699 to 830 A over the same NaCl range Dplat, the diffusion coefficient of the internal subunits, displays a different dependence on the NaCl concentration and decreases, by nearly 22% in a titratable fashion, from 12.46 X 10(-8) to 10.26 X 10(-8) cm2/s, when the salt is increased from 100 microM to 1.0 M. A semiquantitative interpretation of these results is provided by analysis of the light scattering data in terms of the circular Rouse-Zimm chain. Rouse-Zimm model parameters are estimated from the experimental results, assuming the circular chains are composed of a fixed number of Gaussian segments, N + 1 = 15. The rms displacement of the internal segments, b, is estimated to be the smallest (442 A) in 100 mM NaCl. Increases of b to 467 A in 100 microM and 524 A in 1.0 M NaCl are observed. Meanwhile, the hypothetical friction factor of the internal subunits, f, progressively increases as the NaCl concentration is raised. It is inferred from the evaluated Rouse-Zimm model parameters that both the static flexibility of the circular chain and diffusive displacements of the internal subunits decrease with increases in NaCl concentration from 100 mM to 1.0 M.(ABSTRACT TRUNCATED AT 400 WORDS)

Chemical Phenomena↗
PubMed1988

The acid instability of myelin. A model for myelin degeneration in multiple sclerosis.

Electron micrographs of samples of bovine spinal cord which have been briefly acidified (10 mM lactate buffer, pH 5.5, 25 degrees C, 15 minutes) prior to being fixed for EM examination, reveal extensive vesicular disruption of the myelin lamellae; micrographs of control samples incubated under identical conditions at pH 7.0, show normal compact lamellae. Culture of thioglycollate-elicited rat peritoneal macrophages in the presence of derivatized, non-ingestible, bovine CNS material results in the secretion of lactic acid and the acidification of the culture medium to levels which are comparable to those which cause lamellae disruption in the tissue slices. Because of the sensitivity of the myelin lamellae to an acidic microenvironment, it is suggested that a local hyperlactemia, with the resulting decrease in interstitial pH, may be a major pathological process in cell-mediated inflammatory demyelination. Antihyperlactemics may therefore provide a new therapeutic approach to minimizing myelin degeneration in multiple sclerosis and in other CNS disorders characterized by inflammatory demyelination.

Animals↗
PubMed1988

Prevention of nitroimidazole resistance in Campylobacter pylori by coadministration of colloidal bismuth subcitrate: clinical and in vitro studies.

One hundred patients with duodenal ulceration and Campylobacter pylori in their stomach were entered into a double blind placebo controlled prospective study. Treatment schedules were cimetidine and placebo, or cimetidine and tinidazole, or colloidal bismuth subcitrate (CBS) and placebo, or CBS and tinidazole. Seventeen per cent of isolates of C pylori obtained at the first endoscopy were resistant to tinidazole and 70% of the second isolates from patients given cimetidine and tinidazole became tinidazole resistant. Suspensions of nitroimidazole sensitive cultures of C pylori showed that three of 22 isolates had a nitroimidazole resistant subpopulation. In patients who healed and remained free of C pylori after treatment ulcers recurred less often than in patients who healed but retained C pylori (23% v 73% over 12 months, p less than 0.001).

Anti-Ulcer Agents↗
PubMed1988

Concentrations of serotonin in plasma--a test for appendicitis?

We assessed the value of measuring serotonin (5-hydroxytryptamine) in plasma (by HPLC) in the diagnosis of acute appendicitis. Values for patients with subsequently confirmed appendicitis (11-145 nmol/L, median 70 nmol/L) significantly (P congruent to 0.005) exceeded those for patients with abdominal pain in whom appendicitis was only a possible diagnosis (2-45 nmol/L, median 20 nmol/L). The results for appendicitis patients were bimodally distributed, with low results found in patients where surgery revealed gangrenous appendicitis with little viable appendicular tissue. We conclude that measuring serotonin may be of value in confirming or excluding the diagnosis of early acute appendicitis where the physical signs are equivocal, and thus helps reduce unnecessary appendectomies. However, serotonin is of little help in diagnosing gangrenous appendicitis, where physical signs are more likely to be clearcut.

Appendectomy↗
PubMed1987

Response of Campylobacter pyloridis to antibiotics, bismuth and an acid-reducing agent in vitro--an ultrastructural study.

Campylobacter pyloridis was cultured for maximal growth in liquid medium, and effects of exposure to various beta-lactam and macrolide antibiotics, metronidazole, tripotassium dicitrato bismuthane (TDB) and cimetidine were monitored by transmission electronmicroscopy after periods of exposure up to 24 h. With amoxycillin and benzylpenicillin (0.12-1 mg/L) and cephalexin (2 mg/L) the normal bacilliform morphology was replaced by bulging and dumb-bell-like profiles showing cell-wall blebbing and vesiculation, and eventually by swollen forms with incomplete cell walls undergoing lysis. These changes developed progressively between 2 h and 24 h and were accelerated at the higher antibiotic concentrations. Erythromycin and clindamycin caused central clearing, ribosomal coagulation and impaired cross-wall formation. There were no gross structural changes in the presence of metronidazole (4 mg/L), TDB (1000 and 2400 mg/L) or cimetidine (1000 and 2000 mg/L); but with TDB focal accumulation of particulate bismuth complex was detected under the cell wall, affecting nearly all organisms by 24 h. In parallel viability tests, metronidazole and TDB both showed bactericidal activity, but cimetidine did not. These findings support the clinical experience that favours combination therapy with bismuth plus an appropriate systemic antibiotic as the regimen of choice for effective clearance of the organisms in C. pyloridis-associated gastritis.

Amoxicillin↗
PubMed1986

Cyclosporine-induced autoimmunity. Conditions for expressing disease, requirement for intact thymus, and potency estimates of autoimmune lymphocytes in drug-treated rats.

These studies explore the phenomenon of cyclosporine-induced autoimmunity in irradiated Lewis rats. We show that (a) the presence of a thymus is required, and autoimmune precursors develop in and exit from this organ to the peripheral lymphocyte pool within a 2-wk period after the initiation of cyclosporine treatment; (b) adoptive transfers of drug-induced autoimmunity to irradiated secondary recipients can be accomplished with relatively few cells of the Th subset, and these transfers of autoimmunity can be blocked by cotransfer of normal lymphoid cells; and (c) potency estimates, using popliteal lymph node assays in syngeneic and F1 recipients indicate similar levels of auto- and alloreactivity by cells from drug-induced autoimmune donors. These various findings indicate that this particular animal model may be useful for studies of the onset and control of autoimmunity, and they raise the possibility that the lack of autoimmunity in normal animals and its induction with cyclosporine may involve similar cellular mechanism as have been found to be operative in GVH reactions and specifically induced immunologic resistance to GVHD.

Animals↗
PubMed1985

Screening for acute pancreatitis: a rapid assay for plasma lipase.

A simple agglutination test for plasma immunoreactive lipase has been evaluated in 101 patients. A positive agglutination reaction was observed if, and only if, plasma lipase exceeded 300 micrograms/l. The test was positive in all 23 patients with acute pancreatitis who were tested on the day of admission to hospital, in one patient with a pancreatitic pseudocyst and in one patient with hyperamylasaemia and hyperlipasaemia due to a perforated duodenal ulcer. The simplicity and reliability of this test make it suitable as an urgent diagnostic investigation for acute pancreatitis.

Acute Disease↗
PubMed1985

Comparison of local anaesthetic techniques in the reduction of Colles' fracture.

A trial comparing the use of Bier's block and the direct infiltration of the fracture site with local anaesthetic was carried out to assess their effectiveness in the reduction of Colles' fracture. This showed Bier's block to be superior in terms of patient acceptability and in ease of reduction. The results of the reduction were also significantly better using the Bier's block, as judged by the measurement of the residual displacement on the X-ray.

Aged↗
PubMed1984

A simple screening test for acute pancreatitis.

A urinary test strip for amylase (Rapignost-Amylase) was compared with plasma amylase assay in samples of urine and plasma collected on the day of admission to hospital from 23 patients with acute pancreatitis and 38 patients with other causes of acute abdominal pain. Plasma amylase was greater than 1200 IU/l in 24 patients (23 with pancreatitis and 1 with a perforated duodenal ulcer) and all were Rapignost-Amylase positive. Twenty-nine of the remaining patients were Rapignost-Amylase negative, but there were eight "false positives' with plasma amylase levels of 86-474 IU/l. The Rapignost-Amylase test is of potential value to screen for clinically occult acute pancreatitis.

Acute Disease↗
PubMed1984

Peripheral nerve implants in the spinal cord in experimental animals.

This paper challenges the concept of 'spinal cord autotomy' as an essential process which will prevent the penetration of spinal cord fibres into a peripheral nerve implant. It proposes that mechanical distraction between the graft and the cord is the main reason why spinal cord fibres fail to traverse a graft. Clinical, neurophysiological and histological evidence is presented to show that embedding an autogenous peripheral nerve implant into a trough in the dorsal half of the cord is effective in restoring continuity in some of the long fibre tracts. Reference is made to other recent work which supports these observations. Possible methods of enhancing the number of fibres which traverse the graft are discussed and an attempt is made to anticipate the possible results of the clinical application of this technique in spinal cord injury patients.

Animals↗