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Biomedical subjects

M Wildman

Publications and source records attributed to M Wildman.

17 recordsLinked to original sources
PubMed2004

Sources of variability in uncertain medical decisions in the ICU: a process tracing study.

BACKGROUND: Consistency of medical decision making (equity) is an important component of quality of care. When patients with chronic obstructive pulmonary disease (COPD) present with an exacerbation needing respiratory support they may die if it is not provided. However, if the disease has reached its terminal stage, ventilation will prolong the process of dying. The ventilation outcome is uncertain and there is evidence of variability when this decision is made, the sources of which are not well understood. OBJECTIVES: To identify sources of variability and propose ways of tackling them in order to promote equity in this type of medical decision. METHODS: Six case histories were selected from hospital records of COPD patients. Fourteen senior doctors from seven hospitals in the West Midlands participated. A process tracing approach was used which consisted of (1) withholding case information until specifically requested by the doctors, (2) estimating survival during the decision making process, and (3) concurrent questioning regarding information interpretation and its impact on survival estimates and decisions. RESULTS: The observed decision variability was attributed to doctors attaching importance to different information, gathering different information, and interpreting information differently. There were significant differences between doctors in the amount of information requested. CONCLUSIONS: Differences in information gathering and interpretation by clinicians can result in different decisions being made about the same patient. This variation may exist for other uncertain medical decisions and may be tackled by providing clinicians with prognostic models in the form of usable decision aids.

Aged↗
PubMed2002

Long-term follow-up of patients from the 1989 Q fever outbreak: no evidence of excess cardiac disease in those with fatigue.

BACKGROUND: In 1989, an outbreak of Q fever (C. burnetii infection) with 147 confirmed cases occurred in Solihull, West Midlands. Three patients developed cardiomyopathy in the subsequent 10 years. The cohort has been followed up with respect to the development of fatigue and, in this instance, cardiac effects after the original infection. AIM: To determine whether persisting fatigue after Q fever represented sub-clinical cardiomyopathy. DESIGN: Prospective follow-up study. METHODS: All traceable subjects from the original outbreak, and community age-, sex- and smoking-matched controls, were studied. Questionnaires for idiopathic fatigue, 12-lead ECG, echocardiography, spirometry and shuttle walk distance were undertaken, and a subset with CDC-defined chronic fatigue syndrome had gated cardiac scans. RESULTS: Of the original cohort, 19 had died, three had emigrated and 10 were untraceable. Of the remaining 115, 108 responded to a mailed questionnaire and 87 were investigated further, of whom 85 provided complete data. Two developed aortic valve vegetations, one of whom died. Chronic fatigue syndrome was found in 20% of cases and 5.3% of controls (including those with co-morbidities), falling to 8.2% and 0 when excluding those with co-morbidities. There were no significant differences in ECG and echocardiographic investigations or shuttle-walk distance between those with fatigue and those without. Six of the seven patients with CFS had gated cardiac scans: all were within normal limits. CONCLUSIONS: These findings do not support the existence of a sub-clinical cardiomyopathy in the patients in this cohort who suffer from fatigue after acute Q fever, although endocarditis can occur after acute infection.

Cardiomyopathies↗
PubMed2002

Choosing the surgical mortality threshold for high risk patients with stage Ia non-small cell lung cancer: insights from decision analysis.

The recent British Thoracic Society guidelines recommend that surgical mortality should not be greater than 8% for pneumonectomy and 4% for lobectomy. These cut offs are advanced as guidelines to inform decision making as to whether or not patients with operable lung cancer should be offered surgery. They have been developed from a notion of what acceptable surgical mortality should be. The planning of care for patients with lung cancer involves making choices between different treatments with different outcomes. While it is accepted that the probability of these outcomes is likely to differ among patients, individual patient preferences for them are also likely to vary. Fixed cut offs for surgical mortality mean ignoring this variation. Decision analysis can be used to assist in the complex task of integrating clinical characteristics and varying patient preferences. By considering high risk patients with potentially curable stage Ia non-small cell lung cancer, it is shown that decision analysis has the potential to illuminate decision making and guideline development within the field of cancer care.

Carcinoma, Non-Small-Cell Lung↗
PubMed2002

GABA-like immunoreactivity in nonspiking interneurons of the locust metathoracic ganglion.

Nonspiking interneurons are important components of the premotor circuitry in the thoracic ganglia of insects. Their action on postsynaptic neurons appears to be predominantly inhibitory, but it is not known which transmitter(s) they use. Here, we demonstrate that many but not all nonspiking local interneurons in the locust metathoracic ganglion are immunopositive for GABA (gamma-aminobutyric acid). Interneurons were impaled with intracellular microelectrodes and were shown physiologically to be nonspiking. They were further characterized by defining their effects on known leg motor neurons when their membrane potential was manipulated by current injection. Lucifer Yellow was then injected into these interneurons to reveal their cell bodies and the morphology of their branches. Some could be recognised as individuals by comparison with previous detailed descriptions. Ganglia were then processed for GABA immunohistochemistry. Fifteen of the 17 nonspiking interneurons studied were immunopositive for GABA, but two were not. The results suggest that the majority of these interneurons might exert their well-characterized effects on other neurons through the release of GABA but that some appear to use a transmitter other than GABA. These nonspiking interneurons are therefore not an homogeneous population with regard to their putative transmitter.

Animals↗
PubMed2001

A case-controlled study with dornase alfa to evaluate impact on disease progression over a 4-year period.

BACKGROUND: Chronic endobronchial sepsis and profuse airway secretions dominate pulmonary disease in cystic fibrosis. Recombinant human DNase I (dornase alfa) reduces the viscoelasticity of airway secretions and hence may improve clearance of airway secretions. OBJECTIVES: To evaluate the long-term influence of dornase alfa on disease progression by performing a case-controlled study with dornase alfa over a period of 4 years. METHODS: A cohort of patients with cystic fibrosis who have been treated with dornase alfa were matched with a control group of patients with cystic fibrosis who had not received treatment with dornase alfa. The patients were matched by pulmonary function, age, and then sex. All available measurements of forced expiratory volume in one second (FEV1), height, weight and sputum bacteriology were collected for periods when the patients were free from respiratory exacerbations. RESULTS: Thirty-eight patients were matched. Slopes of median changes in FEV1 were -2.19 (-3.32, -1.06) in the control group and -0.75 (-1.87, 0.36) in the dornase alfa-treated group (p = 0.076). There were more infective exacerbations per patient year in the control group [3.13 (1.25-4.25)] in comparison to the dornase alfa group [1.25 (0.63-3.0), p = 0.035] over the 4-year treatment period. Antibiotic requirements were also greater with a median 43.75 (17.5-60.0) days of intravenous antibiotic use per patient year in the control group and 16.25 (8.5-44.0) days in the dornase alfa group (p = 0.034). CONCLUSIONS: The trends suggest that dornase alfa may have some influence on disease progression but in view of the limitations of the current study the need for further long-term studies in larger cohorts of patients is emphasised.

Adult↗
PubMed2000

Connections between thoraco-coxal proprioceptive afferents and motor neurons in the locust.

The position of the coxal segment of the locust hind leg relative to the thorax is monitored by a variety of proprioceptors, including three chordotonal organs and a myochordotonal organ. The sensory neurons of two of these proprioceptors, the posterior joint chordotonal organ (pjCO) and the myochordotonal organ (MCO), have axons in the purely sensory metathoracic nerve 2C (N2C). The connections made by these afferents with metathoracic motor neurons innervating thoraco-coxal and wing muscles were investigated by electrical stimulation of N2C and by matching postsynaptic potentials in motor neurons with afferent spikes in N2C. Stretch applied to the anterior rotator muscle of the coxa (M121), with which the MCO is associated, evoked sensory spikes in N2C. Some of the MCO afferent neurons make direct excitatory chemical synaptic connections with motor neurons innervating the thoraco-coxal muscles M121, M126 and M125. Parallel polysynaptic pathways via unidentified interneurons also exist between MCO afferents and these motor neurons. Connections with the common inhibitor 1 neuron and motor neurons innervating the thoraco-coxal muscles M123/4 and wing muscles M113 and M127 are polysynaptic. Afferents of the pjCO also make polysynaptic connections with motor neurons innervating thoraco-coxal and wing muscles, but no evidence for monosynaptic pathways was found.

Afferent Pathways↗
PubMed1996

Sensory feedback and central afferent interaction in the muscle receptor organ of the crab, Carcinus maenas.

1. An interaction exists between two proprioceptive afferent neurons innervating the thoracic-coxal muscle receptor organ (TCMRO) of the crab, Carcinus maenas. Intracellular recordings were made from the extraganglionic regions of the afferents in order to characterize this interaction and its effects on sensory feedback. 2. A current-induced depolarization of the nonspiking T fiber of the TCMRO results in a depolarization of the P fiber, a small-diameter (7 microns) neuron innervating the same receptor. This interaction is graded in amplitude, and may result in a single action potential being superimposed on the graded response of the P fiber. A hyperpolarization of the T fiber has a smaller effect on the P fiber than a depolarization of similar amplitude. The interaction is rectified in a T- to P-fiber direction, and has a minimum central delay of approximately 3.6 ms. 3. The site of the interaction between the afferents is situated centrally, within the thoracic ganglion. Action potentials evoked in the P fiber by a T-fiber depolarization propagate actively and antidromically to the periphery. 4. Central modulation of the interaction occurs, because the amplitude of a T-fiber-induced depolarization is reduced in the P fiber during centrally generated spontaneous bursts of activity in the motoneurons of basal leg muscles. 5. Because of the interaction between T and P fibers, action potentials recorded from the peripheral portion of the P fiber during receptor stretch may be either orthodromic, resulting directly from the effects of the stretch on the sensory endings of the P fiber, or antidromic, resulting from the central input from the T fiber. 6. The T- to P-fiber interaction may serve to extend the dynamic sensitivity range of the P fiber, in particular by amplifying its sensory response at short receptor lengths and low velocities of stretch.

Action Potentials↗
PubMed1990

The submuscular aponeurotic system (SMAS): a histologic and comparative anatomy evaluation.

The submuscular aponeurotic system (SMAS) has been steeped in controversy. The goal of our anatomic study was to further clarify the existence of the SMAS. With an operating microscope, we performed dissections in 10 fresh cadaver heads (20 hemiheads) exposing the SMAS through a face lift incision. Through the operating microscope we were able to identify the SMAS and its relationship to other anatomic structures. Full-thickness longitudinal sections were obtained for routine histologic studies along various surgically relevant regions of the SMAS. In addition, dissections were accomplished with the operating microscope on 12 rhesus monkey fetuses ranging in age from a few weeks to 8 months. Data obtained from the fresh cadaver microdissections, topographic histology, and comparative anatomy revealed the presence of the SMAS as a distinct fibromuscular layer composed of the platysma muscle, parotid fascia, and fibromuscular layer covering the cheek.

Adipose Tissue↗
PubMed1987

Professional liability for using financial criteria in clinical decisions.

Physicians who include in their treatment protocols financial criteria that serve the economic interests of third-party payors or the hospitals in which they practice face an additional burden in malpractice defense. A new delicate balance exists between protecting the patient's welfare and the constraints imposed by government and fiscal intermediaries.

Decision Making↗