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Biomedical subjects

R Ball

Publications and source records attributed to R Ball.

At least 55 records · Page 3Linked to original sources
PubMed1997

Tuberculosis skin test conversion among health care workers at a military medical center.

Health care workers (HCW) are at risk of occupationally acquiring Mycobacterium tuberculosis (TB) infection. The Centers for Disease Control and Prevention has published guidelines for health care facilities to protect HCW. One of the recommended elements is TB infection surveillance among HCW using purified protein derivative (PPD) skin testing and analysis of the data by occupational group and work location to determine areas of increased risk of infection. At the military medical center (MMC) we studied, occupational groups with statistically significant (p < 0.05) above-average PPD conversion risk (> 1.1%/year) included respiratory therapists (15.6%/year), nursing technicians (2.3%/year), and military personnel (1.6%/year). Maintenance and engineering workers (2.6%/year), food service workers (2.5%/year), laboratory workers (2.0%/year), custodial workers (1.8%/year), and practical nurses (1.7%/year) had above-average, but not statistically significant, risk. The fourth floor of the MMC had 39% (21/54) of the converters. The surveillance program also uncovered 235 individuals who had not completed adequate prophylactic therapy, and a case of active TB in a laboratory worker.

Allied Health Personnel↗
PubMed1996

Phospholipase C beta2 association with phospholipid interfaces assessed by fluorescence resonance energy transfer. G protein betagamma subunit-mediated translocation is not required for enzyme activation.

Phospholipase C beta2 (PLC beta2) is activated by G protein betagamma subunits and calcium. The enzyme is soluble and its substrate, phosphatidylinositol 4,5-bisphosphate (PIP2), is present in phospholipid membranes. A potential mechanism for regulation of this enzyme is through influencing the equilibrium association of the enzyme with membrane surfaces. In this paper we describe a fluorescence resonance energy transfer (FRET) method for measuring the association of PLC beta2 with phospholipid bilayers. The method allows equilibrium measurements to be made under a variety of conditions, including those that support enzymatic activity and ability to be regulated by G proteins. Using this method it was found that PLC beta2 bound to vesicles containing anionic lipids and demonstrated a selective and unique interaction with PIP2-containing vesicles. The FRET data were corroborated with a centrifugation based method for estimating the affinity of PLC beta2 for vesicles. Apparently different modes of association of PLC beta2 with vesicles of different composition can be distinguished based on alterations in resonance energy transfer efficiency. Association of PLC beta2 with PIP2 vesicles requires an intact lipid bilayer, is blocked by neomycin, and is not affected by D-myo-inositol 1,4,5-trisphosphate (D-IP3). G protein betagamma subunits do not alter the affinity of PLC beta2 for lipid bilayers and at the PIP2 concentrations used to measure betagamma-dependent stimulation of PLC activity, the majority of the PLC beta2 is already associated with the vesicle surface. Furthermore, under conditions where betagamma subunits strongly activate PLC activity, the extent of association with vesicles is unaffected by betagamma subunits or calcium. These results indicate that activation of PLC beta2 by G protein betagamma subunits or Ca2+ in vitro does not involve translocation to the vesicle surface.

Animals↗
PubMed1996

Regulation of cardiac Na+,Ca2+ exchange and KATP potassium channels by PIP2.

Cardiac Na+,Ca2+ exchange is activated by a mechanism that requires hydrolysis of adenosine triphosphate (ATP) but is not mediated by protein kinases. In giant cardiac membrane patches, ATP acted to generate phosphatidylinositol-4,5-bisphosphate (PIP2) from phosphatidylinositol (PI). The action of ATP was abolished by a PI-specific phospholipase C (PLC) and recovered after addition of exogenous PI; it was reversed by a PIP2-specific PLC; and it was mimicked by exogenous PIP2. High concentrations of free Ca2+ (5 to 20 microM) accelerated reversal of the ATP effect, and PLC activity in myocyte membranes was activated with a similar Ca2+ dependence. Aluminum reversed the ATP effect by binding with high affinity to PIP2. ATP-inhibited potassium channels (KATP) were also sensitive to PIP2, whereas Na+,K+ pumps and Na+ channels were not. Thus, PIP2 may be an important regulator of both ion transporters and channels.

Adenosine Triphosphate↗
PubMed1996

Practical marketing for dentistry. 5. Buyer behaviour.

Although the term 'buyer behaviour' may seem too commercial for the healthcare situation, in dentistry especially most patients 'buy' dental services and many of the principles of buyer behaviour are relevant to marketing in dentistry. This article looks at the factors that influence why people buy what they do.

Attitude to Health↗
PubMed1996

Practical marketing for dentistry. 3. Relationship marketing and patient/customer satisfaction.

In this article, we look at the philosophy of customer focus and value, and how dental practices can produce and deliver high customer value and satisfaction, to retain as well as attract their customers-the patients. Total quality concepts will also be discussed in the context of their relationship with marketing activities. In all cases, where 'customer' is referenced, this means 'patient' in the context of a dentistry, since patients are the customers, their requirements must be considered in targeting the marketing of a dental practice.

Consumer Behavior↗
PubMed1996

Practical marketing for dentistry. 2. The core concepts of marketing.

This series identifies the ideas and concepts behind modern marketing thinking, and suggests areas for consideration when creating a marketing 'culture' within general dental practices, dental supplies businesses, service suppliers, laboratories-or indeed any organisation which wants to succeed in today's challenging conditions.

Costs and Cost Analysis↗
PubMed1996

Practical marketing for dentistry. 1. What is marketing?

Do you really understand what 'marketing' means? Are you suspicious about the motives of those practising marketing? Is it ethical to promote dental and health services? Are we trying to make out that we offer more than we actually do? Is this a scheme dreamed up as a front for inferior services? The aim of this series is to demonstrate that marketing theory and concepts do have an ever increasing importance in today's dental practices. The series will explore different aspects of marketing thought and relate them to the practice environment, by use of practical examples and a case study.

Humans↗
PubMed1996

Angiotensin II-induced fluid phase endocytosis in human cerebromicrovascular endothelial cells is regulated by the inositol-phosphate signaling pathway.

The involvement of the early signaling messengers, inositol tris-phosphate (IP3), intracellular calcium, [Ca2+]i, and protein kinase C (PKC), in angiotensin II (AII)-induced fluid phase endocytosis was investigated in human brain capillary and microvascular endothelial cells (HCEC). ALL (0.01-10 microM) stimulated the uptake of Lucifer yellow CH, an inert dye used as a marker for fluid phase endocytosis, in HCEC by 50-230%. AII also triggered a fast accumulation of IP3 and a rapid increase in [Ca2+]i in cells loaded with the Ca(2+)-responsive fluorescent dye fura-2. The prompt AII-induced [Ca2+]i spike was not affected by incubating HCEC in Ca(2+)-free medium containing 2 mM EGTA or by pretreating the cultures with the Ca2+ channel blockers, methoxyverapamil (D600; 50 microM), nickel (1 mM), or lanthanum (1 mM), suggesting that the activation of AII receptors on HCEC triggers the release of Ca2+ from intracellular stores. The AII-triggered increases in IP3, [Ca2+]i, and Lucifer yellow uptake were inhibited by the nonselective AII receptor antagonist, Sar1, Val5, Ala8-AII (SVA-AII), and by the phospholipase C (PLC) inhibitors, neomycin and U-73122. By contrast, the protein kinase C (PKC) inhibitors, staurosporine and calphostin C, failed to affect any of these AII-induced events. This study demonstrates that increased fluid phase endocytotosis induced by AII in human brain capillary endothelium, an event thought to be linked to the observed increases in blood-brain barrier permeability in acute hypertension, is likely dependent on PLC-mediated changes in [Ca2+]i and independent of PKC.

Angiotensin II↗
PubMed1996

A profile of help-seeking Australian veterans.

While considerable information is available regarding American Vietnam veterans, surprisingly little has appeared concerning veterans of other nationalities who served in the Vietnam war. This paper provides a preliminary profile of help-seeking Australian veterans in order to afford a comparison with the available American data. Collected in the context of a review of the Vietnam Veterans Counselling Service (VVCS), demographic data suggest that the client population is similar in many ways to that of the American posttraumatic stress disorder (PTSD) Clinical Teams. Problems commonly reported by clients of VVCS included posttraumatic stress, relationship difficulties, anxiety, depression, and problems with pensions and benefits. A postal survey of a sub-sample of current clients revealed a mean score on the Combat Exposure Scale of 19.27 and a mean score on the Mississippi Scale for PTSD of 118.43. Again, these findings are broadly comparable with those of American help-seeking veterans.

Adaptation, Psychological↗
PubMed1996

Amino acid profile in Down's syndrome.

Fasting plasma and urinary amino acid concentrations were studied under carefully controlled conditions in 22 children with Down's syndrome and in age matched controls. The only significant difference between the groups was a higher mean plasma lysine concentration in Down's syndrome patients compared to controls.

Amino Acids↗
PubMed1996

Comparison of Beck Depression Inventories -IA and -II in psychiatric outpatients.

The amended (revised) Beck Depression Inventory (BDI-IA; Beck & Steer, 1993b) and the Beck Depression Inventory-II (BDI-II; Beck, Steer, & Brown, 1996) were self-administered to 140 psychiatric outpatients with various psychiatric disorders. The coefficient alphas of the BDI-IA and the BDI-II were, respectively, .89 and .91. The mean rating for Sadness on the BDI-IA was higher than it was on the BDI-II, but the mean ratings for Past Failure, Self-Dislike, Change in Sleeping Pattern, and Change in Appetite were higher on the BDI-II than they were on the BDI-IA. The mean BDI-II total score was approximately 2 points higher than it was for the BDI-IA, and the outpatients also endorsed approximately one more symptom on the BDI-II than they did on the BDI-IA. The correlations of BDI-IA and BDI-II total scores with sex, ethnicity, age, the diagnosis of a mood disorder, and the Beck Anxiety Inventory (Beck & Steer, 1993a) were within 1 point of each other for the same variables.

Adjustment Disorders↗