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Biomedical subjects

J Kruger

Publications and source records attributed to J Kruger.

At least 19 recordsLinked to original sources
PubMed2006

Health-related quality of life, BMI and physical activity among US adults (>/=18 years): National Physical Activity and Weight Loss Survey, 2002.

OBJECTIVE: To examine the association between health-related quality of life (HRQOL) and physical activity (PA). METHODS: Cross-sectional data were obtained via a national telephone survey from 9173 respondents (30.9% response rate; 51.4% cooperation rate). Four indicators of HRQOL were measured: self-rated health, physically unhealthy days, mentally unhealthy days and activity limitation days. Prevalence estimates were calculated by body mass index (BMI) category and PA level. Logistic regression evaluated BMI as an effect modifier of the relationship between HRQOL and PA. RESULTS: Inactive adults reported more fair to poor HRQOL than active adults, regardless of BMI category (P<0.001). BMI did not modify the association between PA and any of the four HRQOL indicators. CONCLUSION: Prevalence of low HRQOL is inversely related to PA participation, and the relationship is not altered by BMI status. Regardless of their weight status, adults should be encouraged to engage in PA.

Adolescent↗
PubMed2001

To trade or not to trade? Criteria for applying cap and trade.

The use of emissions trading (cap and trade) is gaining worldwide recognition as an extremely effective policy tool. The U.S. Sulfur Dioxide (SO2) Emissions Trading Program has achieved an unprecedented level of environmental protection in a cost-effective manner. The successful results of the program have led domestic and foreign governments to consider the application of cap and trade to address other air quality issues. Certain analyses are particularly important in determining whether or not cap and trade is an appropriate policy tool. This paper offers a set of questions that can be used as criteria for determining whether or not cap and trade is the preferred policy approach to an environmental problem.

Acid Rain↗
PubMed2001

You don't know me, but I know you: the illusion of asymmetric insight.

People, it is hypothesized, show an asymmetry in assessing their own interpersonal and intrapersonal knowledge relative to that of their peers. Six studies suggested that people perceive their knowledge of their peers to surpass their peers' knowledge of them. Several of the studies explored sources of this perceived asymmetry, especially the conviction that while observable behaviors (e.g., interpersonal revelations or idiosyncratic word completions) are more revealing of others than self, private thoughts and feelings are more revealing of self than others. Study 2 also found that college roommates believe they know themselves better than their peers know themselves. Study 6 showed that group members display a similar bias-they believe their groups know and understand relevant out-groups better than vice versa. The relevance of such illusions of asymmetric insight for interpersonal interaction and our understanding of "naive realism" is discussed.

Cognition↗
PubMed2000

Deficiency of Src homology 2-containing phosphatase 1 results in abnormalities in murine neutrophil function: studies in motheaten mice.

Neutrophils, an essential component of the innate immune system, are regulated in part by signaling pathways involving protein tyrosine phosphorylation. While protein tyrosine kinase functions in regulating neutrophil behavior have been extensively investigated, little is known about the role for specific protein tyrosine phosphatases (PTP) in modulating neutrophil signaling cascades. A key role for Src homology 2 domain-containing phosphatase 1 (SHP-1), a PTP, in neutrophil physiology is, however, implied by the overexpansion and inappropriate activation of granulocyte populations in SHP-1-deficient motheaten (me/me) and motheaten viable (me(v)/me(v)) mice. To directly investigate the importance of SHP-1 to phagocytic cell function, bone marrow neutrophils were isolated from both me/me and me(v)/me(v) mice and examined with respect to their responses to various stimuli. The results of these studies revealed that both quiescent and activated neutrophils from motheaten mice manifested enhanced tyrosine phosphorylation of cellular proteins in the 60- to 80-kDa range relative to that detected in wild-type congenic control neutrophils. MOTHEATEN: neutrophils also demonstrated increased oxidant production, surface expression of CD18, and adhesion to protein-coated plastic. Chemotaxis, however, was severely diminished in the SHP-deficient neutrophils relative to control neutrophils, which was possibly attributable to a combination of defective deadhesion and altered actin assembly. Taken together, these results indicate a significant role for SHP-1 in modulating the tyrosine phosphorylation-dependent signaling pathways that regulate neutrophil microbicidal functions.

Animals↗
PubMed2000

An extended Glasgow Coma Scale (GCS-E) with enhanced sensitivity to mild brain injury.

OBJECTIVE: The Glasgow Coma Scale-Extended (GCS-E) was developed to flag mild cases of concussion (corresponding to Grades I and II concussion as defined by the American Academy of Neurology) at the time of first contact with the health care system. SUBJECTS AND SETTING: The GCS-E was applied to 561 consecutive admissions with GCS scores of 13 to 15 at two hospitals in South Africa and two in the United Kingdom (UK). RESULTS: The amnesia scale was readily learned and reliably applied by emergency department staff without affecting the standard scoring of the GCS itself. Among patients with an admitting GCS of 15, 27% in the UK and 31% in South Africa reported amnesia of some duration. CONCLUSIONS: Wide use of the GCS-E would hold mild traumatic brain injury cases in the treatment loop, improve access to counselling, rehabilitation services, and personal injury compensation, and reduce the "cognitive dissonance" between victims of mild traumatic brain injury and treating professionals.

Adult↗
PubMed2000

Perceptions of injury causes and solutions in a Johannesburg township: implications for prevention.

As with other diseases, citizen perceptions of injury causes and solutions are important determinants of their response to the problem. This study explores qualitative responses to questions about the causes and solutions for injuries due to violence, transport, and unintentional burns, falls and other causes from 1,075 residents in six neighbourhoods of a low-income area in Johannesburg, South Africa. These included council houses, council apartment blocks and informal settlements. Data were analysed using content analytic procedures. Perceived causes of injury varied sharply between neighbourhoods. Violence was seen as an outcome of unemployment, socialisation, drug abuse and drug dealing in the formal housing areas, while in the informal settlements it was attributed to unemployment, poor housing and environmental conditions, and excessive alcohol consumption. In the formal housing areas, suggested solutions for violence emphasised increased policing and other repressive measures that contradicted the attribution of causes to environmental factors. In the informal areas, solutions were more congruent with perceived causes, emphasising housing development, education and employment. Perceived causes and solutions for transport injuries reflected the specific context of each neighbourhood, and indicated strong support for the implementation of environmental modifications to reduce the speed of motor vehicles and thus the number of pedestrian injuries. Where perceived causes and solutions for violence and transport-related injuries were located beyond the community in the broader environment, unintentional injuries due to other causes were seen as more in the sphere of potential personal control, except in the informal areas where electrification and formal housing provision were the most commonly suggested solutions. Popular constructions of the causes and solutions for major categories of injury are important in shaping injury prevention responses, and their careful assessment can increase the likelihood that safety promotion programmes will succeed.

Accident Prevention↗
PubMed2000

X-ray attenuation coefficients of high-atomic-number, hexanuclear transition metal cluster compounds: a new paradigm for radiographic contrast agents.

RATIONALE AND OBJECTIVES: The purpose of this study was to examine the radiologic attenuation properties of the parent cluster compounds, particularly attenuation as a function of discrete photon energy, before investigating ligand substitutions, which are necessary to improve cluster biocompatibility and to impart desirable physicochemical properties. MATERIALS AND METHODS: The linear attenuation coefficients for solutions of the cluster compounds Ta6Br14, K8Ta6O19, and (H3O)2W6Cl14 were determined at 60, 80, 103, 122, and 140 keV from gamma-ray transmission measurements with americium-241, xenon-133, gadolinium-153, cobalt-57, and technetium-99m radioactive sources. Transmission measurements were obtained for a fixed time interval that ensured a statistically accurate count distribution exceeding 20,000 counts through the sample for each trial. RESULTS: On a strictly mole per liter basis, a 0.075 mol/L aqueous solution of K8Ta6O19 showed 1.08 times the attenuation of 0.063 mol/L aqueous iohexol at 60 keV and 3.30 times the attenuation at 80 keV. Similarly, a 0.05 mol/L methanolic solution of (H3O)2W6Cl4 showed 0.96 times (96%) the attenuation of 0.063 mol/L aqueous iohexol at 60 keV but 3.09 times the attenuation of the iohexol solution at 80 keV. Attenuations of 0.063 mol/L aqueous iohexol and 0.0125 mol/L Ta6Br14 (ie, at approximately one-fifth the iohexol concentration) were comparable at greater than 60 keV. CONCLUSION: These results confirm the theoretic potential for use of early transition metal cluster compounds as radiographic contrast agents. At higher x-ray energies, cluster compounds demonstrate multiplied x-ray attenuation relative to iodinated contrast agents.

Contrast Media↗
PubMed2000

Tracheal constrictor drive above the apneic threshold in anesthetized dogs.

We have previously shown that raising arterial PCO(2) (Pa(CO(2))) by small increments in dogs ventilated below the apneic threshold (AT) results in almost complete tracheal constriction before the return of phrenic activity (Dickstein JA, Greenberg A, Kruger J, Robicsek A, Silverman J, Sommer L, Sommer D, Volgyesi G, Iscoe S, and Fisher JA. J Appl Physiol 81: 1844-1849, 1996). We hypothesized that, if increasing chemical drive above the AT mediates increasing constrictor drive to tracheal smooth muscle, then pulmonary slowly adapting receptor input should elicit more tracheal dilation below the AT than above. In six methohexital sodium-anesthetized, paralyzed, and ventilated dogs, we measured changes in tracheal diameter in response to step increases in tidal volume (VT) or respiratory frequency (f) below and above the AT at constant Pa(CO(2)) ( approximately 40 and 67 Torr, respectively). Increases in VT (400-1,200 ml) caused significantly more (P = 0.005) tracheal dilation below than above AT (7.0 +/- 2.2 vs. 2.8 +/- 1.0 mm, respectively). In contrast, increases in f (14-22 breaths/min) caused similar (P = 0.93) tracheal dilations below and above (1.0 +/- 1.3 and 1.0 +/- 0.8 mm, respectively) AT. The greater effectiveness of dilator stimuli below compared with above the AT is consistent with the hypothesis that drive to tracheal smooth muscle increases even after attainment of maximal constriction. Our results emphasize the importance of controlling PCO(2) with respect to the AT when tracheal smooth muscle tone is experimentally altered.

Animals↗
PubMed2000

Determination of the lowest dilution of aluminium acetate solution able to inhibit in vitro growth of organisms commonly found in chronic suppurative otitis media.

Burow's solution has been found to inhibit the in vitro growth of most commonly occurring bacteria found in the discharging ear. These organisms were inoculated onto appropriate agar plates that contained serial dilutions of aluminium acetate. Results show that the lowest dilution able to inhibit the growth of these organisms lies between a 1:80 and a 1:160 dilution of Burow's solution.

Acetates↗
PubMed1999

Lake Wobegon be gone! The "below-average effect" and the egocentric nature of comparative ability judgments.

Like the inhabitants of Garrison Keillor's (1985) fictional community of Lake Wobegon, most people appear to believe that their skills and abilities are above average. A series of studies illustrates one of the reasons why: when people compare themselves with their peers, they focus egocentrically on their own skills and insufficiently take into account the skills of the comparison group. This tendency engenders the oft-documented above-average effect in domains in which absolute skills tend to be high but produces a reliable below-average effect in domains in which absolute skills tend to be low (Studies 1 and 2). In Study 3, cognitive load exacerbated these biases, suggesting that people "anchor" on their assessment of their own abilities and insufficiently "adjust" to take into account the skills of the comparison group. These results suggest that the tendency to see oneself as above average may not be as ubiquitous as once thought.

Cognition↗
PubMed1999

Unskilled and unaware of it: how difficulties in recognizing one's own incompetence lead to inflated self-assessments.

People tend to hold overly favorable views of their abilities in many social and intellectual domains. The authors suggest that this overestimation occurs, in part, because people who are unskilled in these domains suffer a dual burden: Not only do these people reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the metacognitive ability to realize it. Across 4 studies, the authors found that participants scoring in the bottom quartile on tests of humor, grammar, and logic grossly overestimated their test performance and ability. Although their test scores put them in the 12th percentile, they estimated themselves to be in the 62nd. Several analyses linked this miscalibration to deficits in metacognitive skill, or the capacity to distinguish accuracy from error. Paradoxically, improving the skills of participants, and thus increasing their metacognitive competence, helped them recognize the limitations of their abilities.

Cognition↗
PubMed1998

The antibacterial activity of acetic acid and Burow's solution as topical otological preparations.

At present there are no topical otological preparations on the World Health Organisation's essential drug list, largely due to the ototoxic potential of preparations containing aminoglycoside antibiotics. Acetic acid and Burow's solution have long been used in the treatment of the discharging ear. The aim of this study was to ascertain the antibacterial activity of these two preparations against the most commonly occurring bacteria isolated from discharging ears in our department. Twenty fresh isolates of each of the following organisms--Pseudomonas aeruginosa, Staphylococcus aureus, Proteus mirabilis and Streptococcus pyogenes--were plated onto blood agar and tested against one per cent, two per cent and three per cent acetic acid and Burow's solution (13 per cent aluminium acetate). The activity of each agent was ascertained by the size of the zone of inhibition of bacterial growth. Burow's solution showed significantly larger average zones of inhibition than acetic acid (p < 0.001). The two per cent and three per cent acetic acid as well as the Burow's solution were active against all the organisms tested.

Acetates↗
PubMed1998

A simple breathing circuit minimizing changes in alveolar ventilation during hyperpnoea.

Many clinical and research situations require maintenance of isocapnia, which occurs when alveolar ventilation (V'A) is matched to CO2 production. A simple, passive circuit that minimizes changes in V'A during hyperpnoea was devised. It is comprised of a manifold, with two gas inlets, attached to the intake port of a nonrebreathing circuit or ventilator. The first inlet receives a flow of fresh gas (CO2=0%) equal to the subject's minute ventilation (V'E). During hyperpnoea, the balance of V'E is drawn (inlet 2) from a reservoir containing gas, the carbon dioxide tension (PCO2) approximates that of mixed venous blood and therefore contributes minimally to V'A. Nine normal subjects breathed through the circuit for 4 min at 15-31 times resting levels. End-tidal PCO2 (Pet,CO2) at rest, 0, 1.5 and 3.0 min were (mean+/-SE) 5.1+/-0.1 kPa (38.1+/-1.1 mmHg), 4.9+/-0.1 kPa (36.4+/-1.1 mmHg), 5.0+/-0.2 kPa (37.8+/-1.6 mmHg) and 5.0+/-0.2 kPa (37.6+/-1.4 mmHg) (p=0.53, analysis of variance (ANOVA)), respectively; without the circuit, Pet,CO2 would be expected to have decreased by at least 2.7 kPa (20 mmHg). Six anaesthetized, intubated dogs were first ventilated at control levels and then hyperventilated by stepwise increases in either respiratory frequency (fR) from 10 to 24 min(-1) or tidal volume (VT) from 400 to 1,200 mL. Increases in fR did not significantly affect arterial CO2 tension (Pa,CO2) (p=0.28, ANOVA). Only the highest VT decreased Pa,CO2 from control (-0.5 +/- 0.3 kPa (-3.4 +/- 2.3 mmHg), p<0.05). In conclusion, this circuit effectively minimizes changes in alveolar ventilation and therefore arterial carbon dioxide tension during hyperpnoea.

Adult↗
PubMed1996

PCO2 affects tracheal tone during apnea in anesthetized dogs.

We hypothesized that CO2, like hypoxia and withdrawal of pulmonary slowly adapting receptor input, would cause tracheal constriction during neural apnea (absence of phrenic activity). In seven anesthetized paralyzed dogs ventilated to neural apnea, we increased arterial PCO2 (PaCO2) in steps by adding CO2 to the inspirate while keeping ventilation constant. Increases in PaCO2 caused tracheal constriction during neural apnea in all dogs; 69 +/- 26 (SD)% of the change in tracheal diameter occurred during neural apnea. Average sensitivity of tracheal diameter to CO2 was 0.44 mm/Torr PaCO2. Our data suggest that central chemoreceptor inputs to brain stem neurons controlling smooth muscle of the extrathoracic airway bypass central mechanisms generating inspiration.

Animals↗
PubMed1995

Hospital-based alcohol and drug specialty consultation service: does it work?

The goals of this report are to describe the development of an inpatient-based alcohol and drug abuse consultation service in a university hospital. At the University of Wisconsin Hospital, we collected data on baseline diagnosis, health services, and costs for inpatients who received such a consultation in 1992-1993 (n = 1,098, 3.5% of all admissions). Follow-up interviews were conducted on a sample of 175 subjects. At the initial assessment, 65% were nicotine dependent, and 50% met criteria for alcohol dependence, 19% for alcohol abuse, 13% for alcohol and drug abuse/dependence. The average cost to patients for a consultation was $220. At the 6-month follow-up interview (n = 175), 42% of the subjects reported complete abstinence, 70% reported reductions in use, and 56% participated in an alcohol and drug treatment program. An inpatient-based alcohol and drug abuse consultation service provides a critical benefit that has not previously been offered in most academic medical centers.

Adolescent↗