Biomedical subjects
B Williams
Publications and source records attributed to B Williams.
Pathogenesis of syringomyelia.
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Syringobulbia: a surgical review.
Syringobulbia is a term which is applied to brain stem symptoms or signs in patients with syringomyelia or hindbrain herniation. Syringobulbia clefts due to a dissection of the CSF under pressure from the fourth ventricle should be differentiated from the ascending syringobulbia which may occur from upward impulsive fluid movements in a syringomyelia. Clinical analysis suggests that the commonest correlation of bulbar features is with neither of the above mechanisms but with pressure differences acting downward upon the hindbrain with distortion of the cerebellum and stem, traction on the cranial nerves or indentation of the brain stem by vascular loops. A review of patients with bulbar symptoms in a neurosurgical practice with an interest in hindbrain herniation in the Midland Centre for Neurosurgery and Neurology (M.C.N.N.) is presented.
Graded pelvic muscle exercise. Effect on stress urinary incontinence.
The purpose of this research was to determine the effect of pelvic muscle exercise (PME) on stress urinary incontinence in middle-aged and elderly women. The protocol required 16 weeks of exercise three times per week, for a total of 48 sessions. Measures were taken at baseline, after a 4-week control period and after 4, 8, 12 and 16 weeks of PME, corresponding to PME levels 1, 2, 3 and 4, respectively. Urine loss was evaluated using a urinary diary and 24-hour pad test at baseline, after the control period and after PME levels 2 and 4. Pelvic muscle function was evaluated every four weeks. Sixty-five parous women 35-75 years of age (mean, 51.3) with mild to moderate stress urinary incontinence were studied. No significant changes in the outcome variables were found after the control period. The results showed significant reductions in urine loss on the 24-hour pad test (t = -4.7, P < or = .0001), and episodes of urine loss decreased from 2.6 to 1.0 between the control period and PME level 4. In addition, a significant improvement occurred in pressures developed by the pelvic muscles in response to PME (t = 6.8, P < or = .0001). Significant correlations between changes in pelvic muscle pressure and in urine loss variables were not found. Women who completed the study experienced a significant reduction in the amount of urine loss as well as a significant increase in pelvic muscle characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)
Evaluating the collaborative approach.
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Surgical treatment of syringobulbia.
The treatment of syringobulbia requires a precise diagnosis of the etiology. This allows a surgical procedure directed at treating the underlying etiology or decompressing the hindbrain. In most cases, symptoms can be greatly improved.
Sensory loss in syringomyelia: not necessarily dissociated.
The pattern of sensory loss was assessed in 210 cases of syringomyelia. Dissociated sensory loss occurred in 49% of cases, indicating that its occurrence is not a necessary finding for the diagnosis of syringomyelia. Syringomyelia should be considered in the differential diagnosis of all cases of spinal cord disease.
Quantitative competitive polymerase chain reaction for accurate quantitation of HIV DNA and RNA species.
Inherent features of the PCR make this procedure suboptimal for quantitative applications. For typical clinical specimens, the absolute amount of product derived from PCR does not always bear a consistent relationship to the amount of target sequence present at the start of the reaction. Competitive PCR approaches to quantitation of nucleic acid sequences overcome the limitations of basic PCR methods for quantitation. We have developed a competitive PCR method known as quantitative competitive PCR for quantitation of HIV DNA and RNA sequences. Key features of the technique include quantitation, based on the relative amounts of products produced from the target sequence and a competitive template introduced into test specimens, and stringent internal control of all reactions, including the reverse transcription step in RNA PCR. The method is suitable for analysis of clinical specimens and may be particularly valuable for accurate quantitation of viral load in patients undergoing treatment with experimental therapies.
Quantification of beta A4 protein deposition in the medial temporal lobe: a comparison of Alzheimer's disease and senile dementia of the Lewy body type.
The distribution of beta-amyloid protein (beta A4) was examined in the medial temporal lobes from cases of Alzheimer's disease (AD) (n = 13), senile dementia of Lewy body type (SDLT) (n = 12) and age matched controls (n = 9). Using a previously described image analysis technique the extent of beta A4 pathology was determined in ten distinct anatomical sites within the medial temporal lobe. AD and SDLT cases contained very similar amounts of beta A4 in the areas sampled and both contained significantly more beta A4 than the age matched controls, particularly in the dentate and parahippocampal gyri. The similarity of the beta A4 load in the two conditions is in contrast to reported differences in the number of neurofibrillary tangles which can be observed. It is suggested that AD and SDLT represent a spectrum of pathology which centres around the aberrant processing of the beta A4 precursor protein.
Evaluation of nurse triage in a British accident and emergency department.
OBJECTIVE: To compare formal nurse triage with an informal prioritisation process for waiting times and patient satisfaction. SETTING: Accident and emergency department of a district general hospital in the midlands in 1990. DESIGN: Patients attending between 8:00 am and 9:00 pm over six weeks were grouped for analysis according to whether triage was operating at time of presentation and by their degree of urgency as assessed retrospectively by an accident and emergency consultant. PATIENTS: 5954 patients presenting over six weeks. MAIN OUTCOME MEASURES: Time waited between first attendance in the department and obtaining medical attention, and patient satisfaction measured by questionnaire. RESULTS: Complete data on waiting time were collected on 5037 patients (85%). Only 1213 of the 2515 (48%) patients presenting during the triage period were seen by a triage nurse. Patients in the triage group waited longer than those in the no triage group in all four retrospective priority categories, though differences were significant for only the two most urgent categories (difference in median waiting time 10.5 (95% confidence interval 3.5 to 14) min for category 1 and 8.5 (3 to 12) min for category 2). Responses to the patient satisfaction questionnaire were similar in the two groups except for the question relating to anxiety relating to pain. CONCLUSIONS: This study fails to show the benefits claimed for formal nurse triage. Nurse triage may impose additional delay for patient treatment, particularly among patients needing the most urgent attention.
Demonstration of processing and recycling of biologically active V1 vasopressin receptors in vascular smooth muscle.
The present study examines the binding and postbinding cellular processing and recycling of the V1 arginine vasopressin (AVP) receptor in cultured vascular smooth muscle cells (VSMCs). The surface binding of AVP to VSMCs was temperature dependent and reached equilibrium within 60 min at 4 degrees C. Displacement studies with unlabeled AVP or a specific V1 AVP antagonist revealed a single class of V1 receptors (Bmax, 1.99 pmol [corrected] per mg of protein; Kd, 2.15 nM). Incubation of VSMCs with unlabeled 10 nM AVP to promote receptor internalization resulted in a time- and temperature-dependent loss of AVP surface binding. At 37 degrees C, maximum loss of binding sites (65%) occurred within 20 min. Recovery of AVP binding occurred rapidly (t1/2, 15-20 min at room temperature) and was uninfluenced by inhibiting protein synthesis with cycloheximide. Pretreating VSMCs with chloroquine prevented AVP receptor recycling, indicating that the AVP-receptor complex requires endosomal processing. The biological competence of the recycled AVP receptor was shown by AVP-induced Ca2+ uptake. The results of these studies therefore indicate that, after surface binding, the AVP-receptor complex internalizes and dissociates in an endosomal compartment. It is demonstrated that in VSMCs biologically active V1 AVP receptors recycle back to the cell surface, thus attenuating the loss of AVP surface binding sites.
Piloting an evaluation of triage.
This paper takes a broad view of the work involved in pilot studies of evaluation research. Drawing on their experience of preparation for a field experiment in a British Accident and Emergency department, which was to evaluate the effectiveness of a nurse triage system, the authors stress the importance of careful observation of the system to be studied, in the environment in which it is to be studied. In addition, the usual evaluations of research instruments which comprise formal pilot studies are included.
Comparison of four different methods of evaluation on axially corrected tomograms of the condyle/fossa relationship.
One hundred temporomandibular joints of 50 dry skulls were used to determine whether there was a statistically significantly difference among four different techniques that were employed to assess the condyle/fossa relationship on axially corrected tomograms. A two-way analysis of variance was performed and the results indicated that: (1) a highly significant difference in the condyle/fossa relationship existed (p = 0.002) among the various skulls and (2) no significant difference existed between the four techniques employed to assess the condyle/fossa relationship (p = 1).
Rigid internal fixation and the effects on the temporomandibular joint and masticatory system: a prospective study.
A prospective study of 22 patients who underwent a bilateral sagittal osteotomy to advance the mandible and subsequent rigid internal fixation, were examined for signs and symptoms of temporomandibular joint (TMJ) pain and masticatory dysfunction. A modified Helkimo index was used to analyze the anamnestic, clinical, and occlusal data. In addition, 12 of the cases chosen at random were mounted on a semiadjustable (SAM2) articulator and analyzed with the mandibular position indicator (MPI) to determine the amount and the direction of condylar displacement postoperatively. Anamnestic dysfunction decreased because of a reported decrease in muscular pain, joint noise, headache frequency, and parafunctional habits postoperatively. Clinical dysfunction remained unchanged, with a decrease in muscular soreness but with an increased incidence of joint clicking of 7%. The increased incidence of temporomandibular joint pain postoperatively was 4%. Increase in clinical dysfunction was most often seen in women and older patients. Occlusal dysfunction decreased, with the majority of interferences remaining after surgery as a result of insufficient lingual crown torque of the maxillary buccal segments. Occlusion is thought to have played only a minor role in temporomandibular joint and masticatory dysfunction. Reduction in range of motion was 10%, indicating the added benefit of early mobilization with rigid internal fixation procedures. The MPI study found the condyles inferiorly or inferoposteriorly displaced less than 1 mm from their preoperative position. These findings suggest that rigid internal fixation had no adverse effects on the temporomandibular and masticatory system. The variable responses and results can be attributed, at least in part, to the heterogenous population of patients studied and the variations in surgical techniques employed.
QALYs in mental health: a case study.
The applicability of the Charing Cross health indicator (CH-X) to the field of mental health was investigated in a community setting using descriptive statistics and principal components analysis. The CH-X is based on assessments of (i) distress and (ii) disability. Our results suggest that with respect to quality of life in mental health settings measurements of distress may be of greater importance than disability. In addition, the CH-X may be insensitive to variations in the severity of mental disorder and may primarily reflect physical disability as opposed to social disability. QALYs methodology may require the adoption of a multidimensional measure of health in order to fulfil its proposed role in comparing medical and mental health programmes.
Single-dose and steady-state pharmacokinetics and pharmacodynamics of oxycodone in patients with cancer.
The single-dose and steady-state pharmacokinetics and pharmacodynamics of oxycodone have been determined in patients with moderate to severe cancer pain. The mean +/- SD elimination half-life after single-dose administration of intravenous (4.6 mg to 9.1 mg) and oral (9.1 mg) oxycodone was 3.01 +/- 1.37 hours and 3.51 +/- 1.43 hours, respectively. After intravenous administration, the mean +/- SD volume of distribution was 211.9 +/- 186.6 L, and the mean +/- SD total plasma clearance was 48.6 +/- 26.5 L/hr. The mean absolute oral bioavailability of oxycodone was 87%, and the mean +/- SD volume of distribution after oral administration was 249.1 +/- 204.3 L. When administered orally as 10 mg oxycodone hydrochloride every 4 hours, there was no accumulation of oxycodone at steady state and the mean +/- SD steady-state concentration was 34.6 +/- 10.3 micrograms/L. Intravenous oxycodone produced a faster onset of pain relief than oxycodone tablets, but the duration of analgesia was approximately the same (4 hours). However, the incidence of side effects and their severity were significantly higher (p < 0.05) for intravenous oxycodone than for oxycodone tablets. The marked interindividual variation observed in the pharmacokinetics and pharmacodynamics of oxycodone in this study supports the need for individualized dosing regimens.
High-temperature short-time heat inactivation of HIV and other viruses in human blood plasma.
An ultra-short-time heating system was used to process blood plasma spiked with various viruses (HIV, vesicular stomatitis virus, encephalomyocarditis virus). Virus reduction and recovery of plasma proteins were measured at various temperatures from 65 to 85 degrees C. Processing at 77 degrees C and 0.006 s resulted in a high level of virus kill, including greater than or equal to 4.4 log10 HIV, while maintaining protein structure and activity essentially intact.