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Biomedical subjects

R Barry

Publications and source records attributed to R Barry.

At least 19 recordsLinked to original sources

Flux through a hole from a shaken granular medium.

We have measured the flux of grains from a hole in the bottom of a shaken container of grains. We find that the peak velocity of the vibration, v max, controls the flux, i.e., the flux is nearly independent of the frequency and acceleration amplitude for a given value of v max. The flux decreases with increasing peak velocity and then becomes almost constant for the largest values of v max. The data at low peak velocity can be quantitatively described by a simple model, but the crossover to nearly constant flux at larger peak velocity suggests a regime in which the granular density near the container bottom is independent of the energy input to the system.

Journal Article↗

Local jamming via penetration of a granular medium.

We present a series of measurements examining the penetration force required to push a flat plate vertically through a dense granular medium, focusing in particular on the effects of the bottom boundary of the vessel containing the medium. Our data demonstrate that the penetration force near the bottom is strongly affected by the surface properties of the bottom boundary, even many grain diameters above the bottom. Furthermore, the data indicate an intrinsic length scale for the interaction of the penetrating plate with the vessel bottom via the medium. This length scale, which corresponds to the extent of local jamming induced by the penetrating plate, has a square root dependence both upon the plate radius and the ambient granular stress near the bottom boundary, but it is independent of penetration velocity and grain diameter.

Journal Article↗

Brachioradial pruritus--an enigmatic entity.

Brachioradial pruritus (BRP) is an unusual clinical entity resulting in pruritus of the upper arms, classically affecting the skin overlying the proximal heads of the brachioradialis muscles. Seven patients with BRP are described. The upper limb was involved in six patients, being bilateral in four and restricted to the right arm in two. Radiological evidence of cervical vertebral osteoarthritis was seen in five. Three patients reported exacerbation with ultraviolet radiation (UVR), i.e., sunlight. All seven were treated with topical capsaicin and four got significant relief. Two of the remaining three patients found relief from amitryptiline. UVR may act as a trigger in some patients although underlying neurological cervical injury also seems to be an important aetiological factor.

Adult↗

Cluster headache and the sympathetic nerve.

OBJECTIVE: To determine the effect of a sympathetic block at C7 on cluster headache. BACKGROUND: Eleven patients presenting to a pain control unit with cluster headache were included in the study after giving informed consent. METHODS: In all patients, a mixture of 5 mL of 0.5% bupivacaine hydrochloride and 1 cc of methylprednisolone acetate was injected onto the base of the C7 transverse process. RESULTS: The injection was applied during the acute phase of headache in 6 patients and all experienced immediate and complete relief. The other 5 patients received the injection between attacks. Of the 11 patients treated, 8 went into remission by aborting the cluster. In some patients, repeated injections were given before the cluster was aborted. Three patients did not respond to treatment. One patient with chronic paroxysmal hemicrania experienced pain relief of the acute attack after treatment, but the procedure did not abort the subsequent attacks. A surgical sympathectomy removing the stellate ganglion rendered him pain-free for 15 months after which he was lost to follow-up. CONCLUSION: Blocking the sympathetic nerve aborts an acute attack of cluster headache and may play a major role in aborting the cluster. Although only one patient with chronic paroxysmal hemicrania responded to surgical sympathectomy, this procedure may be considered as an alternative if there is poor response to oral medication or a sympathetic block.

Acute Disease↗

The channel-forming protein proaerolysin remains a dimer at low concentrations in solution.

Proaerolysin, the proform of the channel-forming protein aerolysin, is secreted as a dimer by Aeromonas sp. The protein also exists as a dimer in the crystal, as well as in solution, at least at concentrations in the region of 500 microg/ml. Recently it has been argued that proaerolysin becomes monomeric at concentrations below 100 microg/ml and that only the monomeric form of the protoxin can bind to cell surface receptors (Fivaz, M., Velluz, M.-C., and van der Goot, F. G. (1999) J. Biol. Chem. 274, 37705-37708). Here we show, using non-denaturing polyacrylamide electrophoresis, chemical cross-linking, and analytical ultracentrifugation, that proaerolysin remains dimeric at the lowest concentrations of the protein that we measured (less than 5 microg/ml) and that the dimeric protoxin is quite capable of receptor binding.

Aeromonas↗

Interferon plus amantadine versus interferon alone in the treatment of naïve patients with chronic hepatitis C: a UK multicentre study.

BACKGROUND/AIMS: The antiviral agent amantadine may have activity against the hepatitis C virus. To determine whether the combination of interferon-alpha plus amantadine was more effective than interferon monotherapy we conducted a multicentre clinical trial in untreated patients with chronic hepatitis C infection. METHODS: We performed a pilot study in two centres (36 patients) to determine the number needed for a statistically significant clinical trial and then conducted a multicentre, randomized controlled clinical trial involving 14 centres and 143 patients. RESULTS: There was no significant difference in sustained response rates in patients receiving interferon and amantadine compared to those receiving interferon alone. The on treatment response rate at 3 months was 65% on combination vs. 49% on interferon alone (P = 0.05) while the sustained response was 18 and 15%, respectively. CONCLUSIONS: Combination therapy with interferon plus amantadine does not lead to a significant increase in sustained response rates when compared to interferon monotherapy.

Adult↗

Cloning and expression profiling of Hpa2, a novel mammalian heparanase family member.

Heparan sulfate proteoglycans are important constituents of the extracellular matrix and basement membrane. Cleavage of heparan sulfate by heparanase, an endoglycosidase, is implicated in the extravasation of leukocytes and metastatic tumour cells, identifying this enzyme(s) as a target for anti-inflammatory and anti-metastatic therapies. The cloning of a cDNA encoding human heparanase (Hpa1) was reported recently, together with evidence indicating that the hpa1 gene is unique and unlikely to belong to a family of related genes. Here we report the cloning of a cDNA encoding a novel human protein, HPA2, with significant homology to Hpa1. Alternative splicing of the hpa2 transcript yields three different mRNAs, encoding putative proteins of 480, 534, and 592 amino acids. Sequence analyses predict that all three Hpa2 proteins are intracellular, membrane-bound enzymes. Hpa2 also shows a markedly different mRNA distribution to Hpa1 in both normal and cancer tissues. The difference in expression profiles and predicted cellular locations suggests that Hpa2 and Hpa1 proteins have distinct biological functions.

Alternative Splicing↗

Genetic analysis of the thermolabile variant of 5, 10-methylenetetrahydrofolate reductase as a risk factor for ischemic stroke.

Mild hyperhomocysteinemia is a risk factor for atherosclerotic vascular disease. Homozygosity for the C677T mutation in the gene for 5,10-methylenetetrahydrofolate reductase (MTHFR) is frequently associated with hyperhomocysteinemia, particularly in individuals with low levels of serum folate, and has been directly associated with cardiovascular disease in certain populations. The purpose of this study was to establish whether the C677T mutation, which causes thermolabile MTHFR, is a risk factor for ischemic stroke in the Irish population. The homozygous C677T genotype has previously been associated with coronary heart disease in Ireland. We collected blood from 174 individuals (minimum age 60 years) who had suffered an ischemic stroke that was confirmed by computed tomography brain scan. Control subjects (n=183) aged >/=60 years, who had never suffered a stroke or transient ischemic attack, were recruited from hospitals and active retirement groups in the same geographical area. MTHFR genotypes were determined and other known risk factors for stroke were documented. In the control group, the frequency of subjects with the homozygous C677T genotype was 10.4%. In patients who had suffered ischemic stroke, the frequency was 15.5%. This difference was not statistically significant. The odds ratio of stroke for C677T homozygotes, with other genotypes as a reference group, was 1.59, 95% CI=0.85, 2.97. The data indicate that the homozygous C677T MTHFR genotype is at most a moderate risk factor for ischemic stroke.

Aged↗

Gerontological nursing in the 21st century.

The approaching millennium brings not only a muted but also a challenging vision for the future of gerontological nursing. This vision is muted by the rhetoric of the 90s dictating the elimination of costly programs with the potential to diminish quality. It is a vision of challenge to advocate for, protect, demand, and create a new framework that will guarantee high-quality health care for older patients. In an attempt to clarify that vision, this article outlines three areas of gerontological nursing: education, practice, and research. The future direction in these areas will dictate how collective thinking can support health care for older people in the next century and beyond. These components of nursing must be integrated to develop quality care needed by older patients.

Forecasting↗

The biblical teachings on suicide.

This article refutes Professor Margaret Battin's idea that the Bible tolerates and even encourages suicide. Dr. Barry argues that the Bible only allows killing in self-defense or as punishment for serious wrongdoing. To support his view Barry first describes several incidents in the Scriptures where suicide is requested from God and is refused. He next reviews incidents where self-inflicted death is tolerated as an act of devotion to God. He continues by discussing suicides which were condemned by God in both the Old and New Testaments. Dr. Barry concludes that suicide is not tolerated or accepted in the Bible except as the sacrifice of one's life as a means of serving God.

Bible↗

Long-term care: providing for those with disability and chronic illness.

1. The focus of long-term care has widened from concentrating exclusively on the older adult to an inclusive perspective of all ages and population groups needing health care over a prolonged period of time. 2. Long-term care principles must include access to a full range of services, care coordination by professional nurses, community-based networks, and an emphasis on consumer responsibility. 3. Multiple nursing implications exist in the 21st century for care of older persons: education of students and professionals and development of continuum of care services and their evaluation and effectiveness.

Case Management↗

Ruptured abdominal aortic aneurysms--prognostic indicators and complications affecting mortality. A local experience.

Although elective abdominal aortic aneurysm (AAA) repair can be done with a less than 5% mortality rate, ruptured AAAs have a 32-85% mortality rate. The aims of this study were: (i) to identify prognostic factors affecting mortality; (ii) to identify and assess the impact of postoperative complications on mortality; and (iii) to try to identify a subgroup of patients who would not benefit from surgery. The records of 54 patients presenting with ruptured AAAs were reviewed; 49 of these patients were operated on, 43 of them males and 6 females (mean age 67 years). The operative mortality rate was 44%, most patients who died doing so in the intensive care unit. In 14 cases AAA was diagnosed before rupture--6 of these patients died. Factors that had a significant effect on mortality were: (i) associated ischaemic heart disease--83% of these patients died postoperatively; (ii) the degree of shock on admission--66% of patients with a blood pressure on admission of 85 mmHg or less died; and (iii) the number of postoperative complications per patients--those with 2 or more complications had an 83% mortality rate. Factors that did not correlate statistically with mortality were age, time interval to surgery, volume and composition of intra-operative fluid therapy, and length of surgery. The most important correctable error was failure to operate electively. From the factors assessed it was not possible clearly to identify a subgroup of patients in this study who should have been excluded from surgery.

Aged↗

Late complications after aortic surgery.

The incidence of false aneurysms, anastomotic stenoses, and ureteric obstruction is reported to be low in patients who have undergone aortic surgery. The use of intravenous peripheral digital subtraction angiography (IVDSA) with completion excretory urography (CEU) may provide a more sensitive means of long-term detection of these complications. The aim of this study was to (1) establish the incidence of anastomotic aneurysms, anastomotic stenoses, and ureteric obstruction after aortic surgery; (2) identify local and systemic factors that predispose to these complications; and (3) evaluate IVDSA as a single radiologic investigation to diagnose these complications. Forty-four patients who had undergone aortic surgery 1 to 12.3 years previously agreed to undergo IVDSA and CEU. False aneurysms were found at 10 distal anastomoses (none at the aorta), for an anastomotic incidence of 11.2% and a patient incidence of 15.9%. Endarterectomy and the femoral artery as a site of distal anastomosis were important factors in the development of anastomotic aneurysms, as were detected radiologically at eight aortic anastomosis (18%). There were no distal anastomotic stenoses. Hypercholesterolemia was more common in this group (62.5%) than in the overall group (21.2%). Three asymptomatic ureteric obstructions were diagnosed in two patients, both of whom had emergency surgery for ruptured aortic aneurysms. The higher incidence of anastomotic aneurysms, anastomotic stenoses, and asymptomatic ureteric obstruction sound merits careful follow-up. IVDSA with CEU may be a simple and effective method of detection.

Anastomosis, Surgical↗