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Biomedical subjects

S Walker

Publications and source records attributed to S Walker.

At least 109 records · Page 6Linked to original sources
PubMed2000

Escalated focal liver radiation and concurrent hepatic artery fluorodeoxyuridine for unresectable intrahepatic malignancies.

PURPOSE: To evaluate the response, time to progression, survival, and impact of radiation (RT) dose on survival in patients with intrahepatic malignancies treated on a phase I trial of escalated focal liver RT. PATIENTS AND METHODS: From April 1996 to January 1998, 43 patients with unresectable intrahepatic hepatobiliary cancer (HB; 27 patients) and colorectal liver metastases (LM; 16 patients) were treated with high-dose conformal RT. The median tumor size was 10 x 10 x 8 cm. The median RT dose was 58.5 Gy (range, 28.5 to 90 Gy), 1.5 Gy twice daily, with concurrent continuous-infusion hepatic arterial fluorodeoxyuridine (0.2 mg/kg/d) during the first 4 weeks of RT. RESULTS: The response rate in 25 assessable patients was 68% (16 partial and one complete response). With a median potential follow-up period of 26.5 months, the median times to progression for all tumors, LM, and HB were 6, 8, and 3 months, respectively. The median survival times of all patients, patients with LM, and patients with HB were 16, 18, and 11 months, respectively. On multivariate analyses, escalated RT dose was independently associated with improved progression-free and overall survival. The median survival of patients treated with 70 Gy or more has not yet been reached (16.4+ months), compared with 11.6 months in patients treated with lower RT doses (P =.0003). CONCLUSION: The excellent response rate, prolonged intrahepatic control, and improved survival in patients treated with RT doses of 70 Gy or more motivate continuation of dose-escalation studies for patients with intrahepatic malignancies.

Adult↗
PubMed2000

NHS litigation.

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Defensive Medicine↗
PubMed2000

Reagents for the chemical development of latent fingerprints: scope and limitations of benzo[f]ninhydrin in comparison to ninhydrin.

Benzo[f]ninhydrin was compared to ninhydrin for fingerprint development on paper. Overall, the performance of ninhydrin on exhibits was slightly better than that of benzo[f]ninhydrin. The significant advantages of the benzo[f]ninhydrin over ninhydrin were the much stronger fluorescence it gave after treatment with zinc salts and a slightly quicker reaction under ambient conditions. This fluorescence is, however, similar to that obtained with other reagents, such as DFO or ninhydrin analogs. These advantages apparently are not sufficient to justify regular usage of benzo[f]ninhydrin, especially when one considers its low solubility and high cost.

Benzene↗
PubMed2000

Understanding theory of mind in children who are deaf.

Research on theory of mind began in the context of determining whether chimpanzees are aware that individuals experience cognitive and emotional states. More recently, this research has involved various groups of children and various tasks, including the false belief task. Based almost exclusively on that paradigm, investigators have concluded that although "normal" hearing children develop theory of mind by age 5, children who are autistic or deaf do not do so until much later, perhaps not until their teenage years. The present study explored theory of mind by examining stories told by children who are deaf and hearing (age 9-15 years) for statements ascribing behaviour-relevant states of mind to themselves and others. Both groups produced such attributions, although there were reliable differences between them. Results are discussed in terms of the cognitive abilities assumed to underlie false belief and narrative paradigms and the implications of attributing theory of mind solely on the basis of performance on the false belief task.

Adolescent↗
PubMed2000

A human rights critique of the United Kingdom's HIV response.

The National AIDS Trust (NAT) is the United Kingdom's leading HIV policy and advocacy NGO. NAT is committed to promoting a human rights framework for HIV responses through work with communities, governments, professionals, and the private sector, both within the UK and internationally. In this presentation to the XIII International AIDS Conference (abstract WeOrE524), John Godwin and Saul Walker discuss current human rights issues related to HIV/AIDS in the UK, and NAT's perspective on the International Guidelines on HIV/AIDS and Human Rights as an advocacy tool.

HIV Infections↗
PubMed2000

A nurse-led service for termination of pregnancy.

The development of a procedure for a medical termination of pregnancy offers patients greater choice. Nurse-led units aim to provide a supportive, holistic service to patients. Patients value being given detailed written and verbal information and being supported in a dedicated unit.

Abortion, Induced↗
PubMed1999

Randomization-based methods for correcting for treatment changes: examples from the Concorde trial.

We develop analysis methods for clinical trials with time-to-event outcomes which correct for treatment changes during follow-up, yet are based on comparisons of randomized groups and not of selected groups. A causal model relating observed event times to event times that would have been observed under other treatment scenarios is fitted using the semi-parametric approach of Robins and Tsiatis (avoiding assumptions about the relationship between treatment changes and prognosis). The methods are applied to the Concorde trial of immediate versus deferred zidovudine, to investigate how the results would have differed if no participant randomized to deferred zidovudine had started treatment before reaching ARC or AIDS. We consider issues relating to model choice, non-constant treatment effects and censoring.

Anti-HIV Agents↗
PubMed1999

Evaluation of biatrial pacing, right atrial pacing, and no pacing in patients with drug refractory atrial fibrillation.

It has been suggested biatrial pacing may prevent the recurrence of atrial fibrillation (AF). To further evaluate this hypothesis, we performed a randomized, single-blinded study in 19 patients with drug refractory AF. The study compared biatrial pacing with conventional right atrial (RA) pacing and a control period of inhibited pacing. The pacing modes utilized were DDD with a base rate of 70 beats/min for biatrial and RA pace (with and without biatrial resynchronization, respectively) and 40 beats/min for the control period. The duration of each pacing mode was 3 months. The number of AF episodes and their duration were obtained from pacemaker Holter memory (Chorus RM ELA Medical). Comparison of the control period (n = 11) with either pacing strategy showed a significant decrease in the total duration of AF (control 27 +/- 35 days, biatrial 8 +/- 15 days p = 0.02, RA 11 +/- 27 days p = 0.04). However, there was no effect on the number of AF episodes (control 79 +/- 108, biatrial 36 +/- 75 p = 0.32, RA 41 +/- 80 p = 0.11). The total percentage of atrial pacing also significantly increased when the control period (6 +/- 9%) was compared with both RA pace (62 +/- 33%, p = 0.008) and biatrial pace (63 +/- 31, p = 0.003). When biatrial pacing was compared with RA pace (n = 19), there was no significant difference in either the duration of AF (biatrial 16 +/- 26 days vs RA 19 +/- 31 days, p = 0.7) or the number of AF episodes (biatrial 56 +/- 91 vs RA 87 +/- 106, p = 0.34). In conclusion, pacing (either type) at a base rate of 70 beats/min has an antifibrillatory effect when compared with inhibited pacing at 40 beats/min. No additional benefit of biatrial pacing over right atrial pacing was demonstrated in this study.

Aged↗
PubMed1999

Immunization with amyloid-beta attenuates Alzheimer-disease-like pathology in the PDAPP mouse.

Amyloid-beta peptide (Abeta) seems to have a central role in the neuropathology of Alzheimer's disease (AD). Familial forms of the disease have been linked to mutations in the amyloid precursor protein (APP) and the presenilin genes. Disease-linked mutations in these genes result in increased production of the 42-amino-acid form of the peptide (Abeta42), which is the predominant form found in the amyloid plaques of Alzheimer's disease. The PDAPP transgenic mouse, which overexpresses mutant human APP (in which the amino acid at position 717 is phenylalanine instead of the normal valine), progressively develops many of the neuropathological hallmarks of Alzheimer's disease in an age- and brain-region-dependent manner. In the present study, transgenic animals were immunized with Abeta42, either before the onset of AD-type neuropathologies (at 6 weeks of age) or at an older age (11 months), when amyloid-beta deposition and several of the subsequent neuropathological changes were well established. We report that immunization of the young animals essentially prevented the development of beta-amyloid-plaque formation, neuritic dystrophy and astrogliosis. Treatment of the older animals also markedly reduced the extent and progression of these AD-like neuropathologies. Our results raise the possibility that immunization with amyloid-beta may be effective in preventing and treating Alzheimer's disease.

Alzheimer Disease↗
PubMed1999

Reply

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Journal Article↗
PubMed1999

Memory card: A tool to assess patient compliance with peritoneal dialysis.

Lack of compliance with prescribed peritoneal dialysis (PD) therapy is a common cause of inadequate dialysis and poor outcomes. Because measurements of delivered doses are performed infrequently, the values obtained may not reflect actual delivered therapy. To evaluate compliance with therapy and to record accurate and complete treatment history for each patient undergoing automated PD, a memory card with the capability to track and store 2 months of treatment data was developed and incorporated into a commercial PD cycler. The memory card is brought to the clinic during the monthly visit. The data is downloaded into a personal computer (PC) with specific software. The following parameters can be retrieved and displayed as a graph or chart: the time of the exchange, length of the exchange, solution transit time, drain time, automated exchanges and last fill, inflow and drain volume, net ultrafiltration, and times of drain alarms. The data can be displayed as daily therapy, mean of therapy values, or total therapy. With the information available, the renal team can incorporate changes into the prescription and provide feedback to the patient based on his/her compliance record. The data can be transferred to a central data pool via modem. This data collection system can also be used for quality improvement, to model delivered therapy, and to compare compliance scores among centers and by cohorts of patients according to demographic or comorbid conditions.

Data Display↗
PubMed1999

The use of a "side-wire" permanent transvenous pacing electrode for left ventricular pacing.

It has been reported that biventricular pacing can improve the symptomatic status of patients with heart failure. However, using currently available transvenous left ventricular pacemaker leads the implantation procedure is difficult and has a high failure rate. We report the successful use of a new type of left ventricular pacing lead, the 'side-wire' pacing lead. This lead is initially introduced through a specifically designed guiding sheath to aid coronary sinus cannulation and then over a pre-positioned guide wire to aid final positioning. The more widespread introduction of this type of left ventricular pacing lead may reduce the difficulty of left ventricular pacing via the coronary sinus and thus improve the overall success rate of this therapeutic approach.

Electrodes↗
PubMed1999

Biventricular implantable cardioverter defibrillator use in a patient with heart failure and ventricular tachycardia secondary to Emery-Dreifuss syndrome.

We report a case of fully transvenous single-unit biventricular implantable cardioverter defibrillator (ICD) use in a 43-year-old woman with a manifesting carrier form of muscular dystrophy (Emery-Dreifuss syndrome). The indication for biventricular ICD use was progressive heart failure with ventricular arrhythmia, permanent atrial fibrillation and previous VVIR pacemaker insertion. Single-unit transvenous biventricular ICD implantation was undertaken without complication. No potentially serious device malfunction was noted during subsequent follow-up. We conclude that single-unit biventricular ICD implantation is feasible for pacing and ventricular tachyarrhythmia control in patients with underlying atrial fibrillation.

Adult↗