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Biomedical subjects

D Rich

Publications and source records attributed to D Rich.

16 recordsLinked to original sources
PubMed2006

The in vitro activity of selected defensins against an isolate of Pseudomonas in the presence of human tears.

BACKGROUND/AIMS: Pseudomonas aeruginosa is a major cause of severe bacterial keratitis and remains a difficult clinical entity to treat successfully with the current arsenal of antimicrobial agents. Defensins are small cationic peptides with broad in vitro antimicrobial activity and are potential ocular therapeutic agents. The authors characterised the in vitro activity of defensins NP-1 and NP-3a against P aeruginosa in the presence of human tears. METHODS: A clinical Pseudomonas isolate was grown to mid-log phase, and 1 x 10(6 )colony forming units were exposed to the peptides (200 microg/ml) for up to 2 hours in the presence of varying concentrations (10-70%) of human tears. RESULTS: For both peptides in the presence of 10% tears, >3 log units of killing was achieved within 30 minutes. In 70% tears, NP-1 produced >1 log unit of killing at 2 hours, indicating that, although reduced, its activity remained significant. In 20% tears, NP-3a demonstrated 2 log units of killing at 2 hours; however, the antimicrobial activity of this defensin was completely inhibited in the presence of 70% tears. CONCLUSION: These in vitro data suggest that while the microbicidal activity of some defensins may be diminished at the ocular surface in vivo, significant activity is still possible with certain peptides.

Animals↗
PubMed2001

Acceptance of a medical first-responder role by fire fighters.

STUDY OBJECTIVE: In July 1998, a pilot trial which used fire fighters as medical first-responders for the first time in Australia, was implemented in Melbourne. We aimed to assess the impact of the introduction of a medical first-responder role to the fire service, on the fire fighters both professionally and personally. METHODS: Focus groups were conducted at the fire stations located in the study area. Data from the focus groups was collated and examined for themes. The issues identified as important through the focus groups were then incorporated into a questionnaire. RESULTS: The fire fighters located at the pilot stations involved in the first-responder programme appear to view their new role as first-responders as a positive addition to their emergency profession. Some areas of the programme were identified by this study as in need of improvement. Some aspects of the communication strategies utilised by the Fire Brigade were highly criticised. Some aspects of the support system offered by the Fire Brigade also appear to be regarded as unfavourable. CONCLUSION: Results from this study provide useful information on professional fire fighter first-responder programmes and their impact on participating personnel. These results can be used to improve training modules, communication strategies and support services.

Adaptation, Psychological↗
PubMed2001

Photodynamic therapy: the nurse's role.

Patients with neovascular (wet) age-related macular degeneration, the leading cause of blindness in persons older than 50 years in developed countries, experience severe visual loss due to choroidal neovascularization, the growth of abnormal vessels under the retina. Photodynamic therapy is a new treatment modality that combines an intravenous injection of a photosensitizing drug, such as verteporfin, and nonthermal laser light application, which destroys choroidal neovascularization without damaging normal surrounding tissue. It has led to new challenges for nurses working in the ambulatory laser setting, including medication preparation, drug administration, and education regarding precautions and potential systemic side effects of photodynamic therapy.

Choroidal Neovascularization↗
PubMed1999

Children with moderately elevated lead levels: is chelation with DMSA helpful?

This study evaluates the effectiveness (use under routine circumstances) of DMSA (2,3 dimercaptosuccinic acid) and environmental remediation as compared with placebo and environmental remediation on children with blood lead (BPb) levels of 30-45 micrograms/dL (1.45-2.17 mumol/L). The endpoints were BPb at 1 month and 6 months after study entry. This double-blind placebo-controlled trial involved 39 children aged 2-5 years, who were randomized to one course of DMSA or placebo. The mean BPb levels of the two groups at study entry were similar, placebo group 33.0 micrograms/dL (1.59 mumol/L) and the DMSA group 34.9 micrograms/dL (1.68 mumol/L). At 1 month (the end of treatment) the mean BPb levels of the two groups were: placebo group 33.2 micrograms/dL (1.60 mumol/L) and the DMSA group 27.4 micrograms/dL (1.32 mumol/L), p = 0.16. At 6 months, the mean BPb levels were 25.1 micrograms/dL (1.21 mumol/L) for the placebo group and 28.8 micrograms/dL (1.39 mumol/L) for the DMSA-treated group, p = 0.06. Neither of these differences is statistically significant. All children with BPb, in the range studied here, should receive environmental evaluation and remediation; DMSA does not improve long-term blood lead levels.

Chelating Agents↗
PubMed1998

Role of cyclophilin A in the uptake of HIV-1 by macrophages and T lymphocytes.

Cyclophilins are a family of proteins that bind cyclosporin A (CsA) and possess peptidyl-prolyl cis-trans isomerase activity. In addition, they are secreted by activated cells and act in a cytokine-like manner, presumably via signaling through a cell surface cyclophilin receptor. More recently, host-derived cyclophilin A (CyPA) has been shown to be incorporated into HIV-1 virions and its incorporation essential for viral infectivity. Here we present evidence supporting a role for viral-associated CyPA in the early events of HIV-1 infection. We report that HIV-1 infection of primary peripheral blood mononuclear cells can be inhibited by: (i) an excess of exogenously added CyPA; (ii) a CsA analogue unable to enter the cells; (iii) neutralizing antibodies to CyPA. Taken together with our observations that recombinant CyPA-induced mobilization of calcium in immortalized, as well as primary, CD4+ T lymphocytes, and that incubation of T cells with iodinated CyPA, followed by chemical cross-linking, resulted in the formation of a high molecular mass complex on the cell surface, these results suggest that HIV-1-associated CyPA mediates an early event in viral infection via interaction with a cellular receptor. This interaction may present a target for anti-HIV therapies and vaccines.

Animals↗
PubMed1997

Positron emission tomography measurement of cerebral metabolic correlates of yohimbine administration in combat-related posttraumatic stress disorder.

BACKGROUND: We have previously reported an increase in symptoms of anxiety in patients with posttraumatic stress disorder (PTSD) following administration of the beta 2-antagonist yohimbine, which stimulates brain norepinephrine release. Preclinical studies show decreased metabolism in the neocortex and the caudate nucleus with high-dose yohimbine-induced norepinephrine release, but low levels of norepinephrine release result in an increase in metabolism in these areas. METHODS: We used positron emission tomography and fludeoxyglucose F 18 to measure brain metabolism in Vietnam combat veterans with PTSD (n = 10) and healthy age-matched control subjects (n = 10), following administration of yohimbine (0.4 mg/kg) or placebo in a randomized, double-blind fashion. RESULTS: Yohimbine resulted in a significant increase in anxiety in the patients with PTSD, but not in healthy subjects. There was a significant difference in brain metabolic response to yohimbine in patients with PTSD compared with healthy subjects in prefrontal, temporal, parietal, and orbitofrontal cortexes. Metabolism tended to decrease in patients with PTSD and increase in healthy subjects following administration of yohimbine. CONCLUSION: These findings are consistent with our previous hypothesis of enhanced norepinephrine release in the brain with yohimbine in patients with PTSD.

Anxiety Disorders↗
PubMed1997

Positron emission tomography measurement of cerebral metabolic correlates of tryptophan depletion-induced depressive relapse.

BACKGROUND: Short-term depletion of plasma tryptophan has been shown to result in depressive relapse in patients with remission of major depression. Positron emission tomography and single photon emission computed tomography studies implicated the dorsolateral prefrontal cortex, orbitofrontal cortex, thalamus, and caudate nucleus in the pathogenesis of depression. The purpose of this study was to measure cerebral metabolic correlates of tryptophan depletion-induced depressive relapse. METHODS: Patients diagnosed as having major depression (N = 21) who clinically improved with serotonin reuptake inhibitors underwent 2 test days involving tryptophan depletion or placebo, followed 6 hours later by positron emission tomography scanning with fludeoxy-glucose F18. Brain metabolism was compared in patients with (n = 7) and without (n = 14) a tryptophan depletion-induced depressive relapse. RESULTS: Tryptophan depletion resulted in a decrease in brain metabolism in the middle frontal gyrus (dorsolateral prefrontal cortex), thalamus, and orbitofrontal cortex in patients with a depletion-induced depressive relapse (but not in patients without depletion-induced relapse). Decreased brain metabolism in these regions correlated with increased depressive symptoms. Baseline metabolism was increased in prefrontal and limbic regions in relapse-prone patients. CONCLUSION: Specific brain regions, including the middle frontal gyrus, thalamus, and orbitofrontal cortex, may mediate the symptoms of patients with major depression.

Antidepressive Agents↗
PubMed1995

A pharmacologic continuum in the treatment of rhinorrhea: the clinician as economist.

The economics of medications are now of great concern to health-care providers. Pharmacoeconomic issues are by no means simple, and yet, ironically, they assume greater importance in prescribing for modest disorders like rhinorrhea than for life-threatening conditions. The therapeutic continuum of quality and cost becomes foreshortened, and safety is an additional concern. Choosing the appropriate medication for rhinorrhea, then, can pose a challenge to the clinician, just as choosing a vital medication. This paper reviews the usage, quality, and cost of major therapies for the rhinorrhea that occurs secondary to various conditions, including nasal steroids, antihistamines and anticholinergics, and discusses the role of the clinician in factoring costs into therapy.

Cholinergic Antagonists↗
PubMed1994

Physicians, pharmacists, and home infusion antibiotic therapy.

Home infusion antibiotic therapy has been proven effective, safe, and economical for a variety of infectious diseases. Programs for home infusion have been established in hospitals, home care companies, and physician offices. These programs utilize the combined efforts of physicians, pharmacists, and nurses and rely heavily on the active participation of the patient to provide quality care for a fraction of the cost of hospital-based infusion. Additionally, given a choice, patients prefer to receive intravenous antibiotic therapy at home. Current reimbursement policies, however, acknowledge neither the economic benefit to be derived from home therapy nor patient preference for this mode of intravenous antibiotic therapy.

Anti-Bacterial Agents↗
PubMed1987

Rapid contrast sensitivity assessment in keratoconus.

Contrast sensitivity derangement may accompany keratoconus even in the presence of normal or near normal Snellen visual acuity. This has been demonstrated with computer-driven contrast sensitivity test devices. The purpose of this study was to evaluate the utility and efficacy of rapid screening devices for contrast sensitivity testing. However, such devices are often cumbersome and difficult to use clinically. We tested 12 patients with keratoconus on 2 simple chart systems designed to test contrast sensitivity in a rapid and clinically useful manner: the Vistech chart and the Regan multi-contrast visual acuity charts. Both devices detected the contrast sensitivity abnormalities present in early keratoconus, but some patients [with greater than or equal to 6/12 (20/40) visual acuity] were unable to respond to areas of the charts corresponding to high spatial frequency and/or low contrast tasks. Such simple wall charts may be useful in measuring the visual abnormalities in early keratoconus, in monitoring the progression of the disease, and in evaluating various treatment options.

Adult↗
PubMedDate not supplied

Finding the right chemistry.

For most hospital executives, learning that a physician group on their staff plans to affiliate with a practice management company causes significant concern. Unsettling images of a widening gulf between physicians and the hospital, accompanied by struggles over ancillary services, come to mind.

Governing Board↗