Showing papers by "University of South Florida published in 1994"

Verification, Validation, and Confirmation of Numerical Models in the Earth Sciences

Abstract: Verification and validation of numerical models of natural systems is impossible. This is because natural systems are never closed and because model results are always nonunique. Models can be confirmed by the demonstration of agreement between observation and prediction, but confirmation is inherently partial. Complete confirmation is logically precluded by the fallacy of affirming the consequent and by incomplete access to natural phenomena. Models can only be evaluated in relative terms, and their predictive value is always open to question. The primary value of models is heuristic.

Using self‐report questionnaires in OB research: A comment on the use of a controversial method

Abstract: Most studies of organizational behavior rely on reports by people about the variables of interest. The use of one type of report, the self-report where people are asked about their own jobs and their reactions to their jobs, has become the target of criticism by both article authors and reviewers. Many researchers are skeptical about results that come from questionnaires that ask people to report about themselves and their jobs. Skepticism is reflected in reviewers' comments when a paper is dismissed with the often prejudiced and unthoughtful charge that method variance or monomethod bias has produced the observed correlations rather than the constructs of interest. It is less likely that this charge will be raised when people report about others, as with assessment center ratings or performance ratings, even though a single method is used here as well. There are good reasons to be cautious in the use of self-report questionnaires, but reasons for caution are every bit as important for other methodologies as well. For example, Fried, Rowland and Ferris (1984) outlined the many problems that occur with the use of objective physiological measures. There have been serious questions raised about the validity of dimension ratings in assessment centers (e.g. Brannick, Michaels and Baker, 1989; Robertson, Gratton and Sharpley, 1987). Frequent discussions of the problems with self-reports can be found throughout the OB literature (e.g. Brief, Burke, George, Robinson and Webster, 1988; Spector, 1992). Indeed self-reports have been used too frequently to address research questions that they are unable to adequately answer. It seems important, however, that we also consider the appropriate uses and values of self-reports. This paper will be concerned with how self-reports can and cannot be used to help us understand organizational phenomena. It will deal with both issues of construct validity and issues of appropriate inferences that can be made from studies using self-report questionnaires.

The orderly progression of melanoma nodal metastases.

Abstract: Objective The aim of this study was to determine the order of melanoma nodal metastases. Summary background data Most solid tumors are thought to demonstrate a random nodal metastatic pattern. The incidence of skip nodal metastases precluded the use of sampling procedures of first station nodal basins to achieve adequate pathological staging. Malignant melanoma may be different from other malignancies in that the cutaneous lymphatic flow is better defined and can be mapped accurately. The concept of an orderly progression of nodal metastases is radically different than what is thought to occur in the natural history of metastases from most other solid malignancies. Methods The investigators performed preoperative and intraoperative mapping of the cutaneous lymphatics from the primary melanoma in an attempt to identify the "sentinel" lymph node in the regional basin. All patients had primary melanomas with tumor thicknesses > 0.76 mm and were considered candidates for elective lymph node dissection. The sentinel lymph node was harvested and submitted separately to pathology, followed by a complete node dissection. The null hypothesis tested was whether nodal metastases from malignant melanoma occurred in equal proportions among sentinel and nonsentinel nodes. Results Forty-two patients met the criteria of the protocol based on prognostic factors of their primary melanoma. Thirty-four patients had histologically negative sentinel nodes, with the rest of the nodes in the basin also being negative. Thus, there were no skip metastases documented. Eight patients had positive sentinel nodes, with seven of the eight having the sentinel node as the only site of disease. In these seven patients, the frequency of sentinel nodal metastases was 92%, whereas none of the higher nodes had documented metastatic disease. Nodal involvement was compared between the sentinel and nonsentinel nodal groups, based on the binomial distribution. Under the null hypothesis of equality in distribution of nodal metastases, the probability that all seven unpaired observations would demonstrate that involvement of the sentinel node is 0.008. Conclusions The data presented demonstrate that nodal metastases from cutaneous melanoma are not random events. The sentinel lymph nodes in the lymphatic basins can be mapped and identified individually, and they have been shown to contain the first evidence of melanoma metastases. This information can be used to revolutionize melanoma care so that only those patients with evidence of nodal metastatic disease are subjected to the morbidity and expense of a complete node dissection. Because sentinel node histology accurately reflects the histology of the remainder of the lymphatic basin, information gained from the sentinel node biopsy can be used as a prognostic factor for melanoma. These findings demonstrate effective pathologic staging, no decrease in standards of care, and a reduction of morbidity with a less aggressive, rational surgical approach.

Bullies and Their Victims: Understanding a Pervasive Problem in the Schools

Abstract: School violence traditionally has been defined in terms of acts of assault, theft, and vandalism. However, a lesser but more frequent form of violence, “bullying,” affects 15% to 20% of all student...

The contribution of personality traits, negative affectivity, locus of control and Type A to the subsequent reports of job stressors and job strains

Abstract: Personality variables (negative affectivity, locus of control and two components of Type A behaviour), assessed in a cohort of graduating college seniors, were used approximately one year later to predict reports of job stressors (autonomy, role ambiguity, role conflict, workload, constraints and interpersonal conflict) and job strains (job satisfaction, work anxiety, frustration and somatic symptoms). For all variables, except work frustration, personality was a significant predictor. Possible mechanisms by which personality might affect reports of job stressors and strains, explanations for results, and suggestions for future research are discussed.

Choice making to promote adaptive behavior for students with emotional and behavioral challenges.

Abstract: Two analyses investigated the effects of choice making on the responding of elementary school students with emotional and behavioral challenges. In the first analysis, 2 participants were given choices from menus of academic tasks, all of which were pertinent to their educational objectives in English and spelling, respectively. Reversal designs showed that the choice-making conditions increased task engagement and reduced disruptive behavior for both students. An additional analysis was performed with a 3rd student in an effort to further distinguish the effects of choice making from preference. In this study, one of the no-choice phases was yoked to a previous choice-making condition. This analysis demonstrated that the choice-making condition was superior to baseline and yoked control phases as determined by levels of task engagement and disruptive behavior. The findings of the two analyses contribute information relevant to students with emotional and behavioral disorders, and to a growing literature on the desirable effects of choice making for students with disabilities and challenging behaviors.

Influence of physician communication on newly diagnosed breast patients' psychologic adjustment and decision-making

Abstract: Background. Physician-patient communication is of critical importance when a breast cancer diagnosis is made, because the emotionally overwhelmed patient must be educated about her disease and available treatments so she can participate in decisions about her care. A research study addressed the hypothesis that patients whose surgeons used psychotherapeutic techniques during the cancer diagnostic interview would have better psychologic adjustment to their cancer. Methods. One hundred women surveyed 6 months after surgery completed the Cancer Diagnostic Interview Scale (CDIS) and the SCL-90-R, a measure of psychologic well being. Results. Factor analysis of the CDIS revealed that the physician's caring attitude was perceived by the women as most important, with information-giving as a much weaker component. Multiple regression analysis supported the hypothesis that psychologic adjustment was predicted by physician behavior during the cancer diagnostic interview. Other significant predictors of adjustment were a history of psychiatric problems and premorbid life stressors. Conclusions. Provision of information needed for decision-making appears to be valued largely within the context of a caring physician-patient relationship. Specific surgeons' behaviors believed to facilitate patient adjustment include expressing empathy, allowing sufficient time for patients to absorb the cancer diagnosis, providing information, and engaging the patient in treatment decision-making.

Genetic-based new fuzzy reasoning models with application to fuzzy control

Abstract: The successful application of fuzzy reasoning models to fuzzy control systems depends on a number of parameters, such as fuzzy membership functions, that are usually decided upon subjectively. It is shown in this paper that the performance of fuzzy control systems may be improved if the fuzzy reasoning model is supplemented by a genetic-based learning mechanism. The genetic algorithm enables us to generate an optimal set of parameters for the fuzzy reasoning model based either on their initial subjective selection or on a random selection. It is shown that if knowledge of the domain is available, it is exploited by the genetic algorithm leading to an even better performance of the fuzzy controller. >

Using assessment-based curricular intervention to improve the classroom behavior of a student with emotional and behavioral challenges.

Abstract: We evaluated a process of descriptive assessment, functional assessment, and assessment-based intervention with an elementary-school child who was described as having emotional and behavioral challenges, but who also exhibited above-average intelligence and communication skills. During a hypothesis-development phase, information was gathered from several sources including an interview that was conducted directly with the participant. Descriptive information collected during this phase produced five hypotheses about variables maintaining the problem behavior that were then tested experimentally in the classroom environment. The resulting functional assessment data supported the hypotheses. Intervention packages based on the hypotheses were implemented sequentially across English, spelling, and math classes. The interventions were successful in increasing on-task behavior, and the improvements were maintained for the remainder of the school year.

Model for the interpretation of hyperspectral remote-sensing reflectance.

Abstract: Remote-sensing reflectance is easier to interpret for the open ocean than for coastal regions because the optical signals are highly coupled to the phytoplankton (e.g., chlorophyll) concentrations. For estuarine or coastal waters, variable terrigenous colored dissolved organic matter (CDOM), suspended sediments, and bottom reflectance, all factors that do not covary with the pigment concentration, confound data interpretation. In this research, remote-sensing reflectance models are suggested for coastal waters, to which contributions that are due to bottom reflectance, CDOM fluorescence, and water Raman scattering are included. Through the use of two parameters to model the combination of the backscattering coefficient and the Q factor, excellent agreement was achieved between the measured and modeled remote-sensing reflectance for waters from the West Florida Shelf to the Mississippi River plume. These waters cover a range of chlorophyll of 0.2-40 mg/m(3) and gelbstoff absorption at 440 nm from 0.02-0.4 m(-1). Data with a spectral resolution of 10 nm or better, which is consistent with that provided by the airborne visible and infrared imaging spectrometer (AVIRIS) and spacecraft spectrometers, were used in the model evaluation.

Seagrass landscapes: a terrestrial approach to the marine subtidal environment.

Abstract: Subtidal seagrass habitats are prime candidates for the application of principles derived from landscape ecology. Although seagrass systems are relatively simple compared to their terrestrial counterparts in terms of species diversity and structural complexity, seagrasses do display variation in spatial patterns over a variety of scales. The presence of a moving water layer and its influence on faunal dispersal may be a distinguishing feature impacting ecological processes in the subtidal zone. Studying seagrass-dominated landscapes may provide a novel approach to investigating questions regarding self-similarity of spatial patterns, and offers a new perspective for analysing habitat change in a variety of marine environments.

Detection of submicroscopic lymph node metastases with polymerase chain reaction in patients with malignant melanoma.

Abstract: BACKGROUND. The presence or absence of lymph node metastases in patients with malignant melanoma is the most powerful prognostic factor for predicting survival. If regional nodal metastases are found, the 5-year survival for the patient decreases approximately 50%. If the presence or absence of regional nodal metastases will determine which patients receive formal dissections or which patients enter adjuvant trials, then a technique is needed to accurately screen lymph node samples for occult disease. Routine histopathologic examination routinely underestimates the number of patients with metastases. This study was initiated to develop a highly sensitive clinically applicable method to detect micrometastases by examining lymph nodes for the presence of tyrosinase messenger RNA (mRNA). The hypothesis was that if mRNA for tyrosinase is found in the lymph node preparation, that finding is good evidence that metastatic melanoma cells are present. METHODS. The assay is accomplished using the combination of reverse transcription and double-round polymerase chain reaction (RT-PCR). The amplified samples are examined on a 2% agarose gel and tyrosinase cDNA is seen as a 207 base pair fragment. Lymph node preparations from 29 patients who were clinically stage I and II and undergoing elective node dissections were analyzed both by standard pathologic staining and RT-PCR. RESULTS. Eleven of 29 lymph node (38%) samples from 29 patients with intermediate thickness melanoma were pathologically positive. Nineteen of the 29 lymph node preparations (66%) were RT-PCR-positive, and these included all of the pathologically positive samples, so that the false-negative rate was 0. In a spiking experiment, one SK-Mel-28 melanoma cell in a background of one million normal lymphocytes could be detected, thus indicating the sensitivity of this method. In addition, analysis by restriction enzyme mapping showed that the amplified 207-bp PCR product produced is part of the tyrosinase gene sequence. CONCLUSION. The RT-PCR method is an extremely sensitive, reproducible, and efficient technique for the identification of micrometastases in patients with melanoma and could be widely applicable. If clinical correlation is obtained, staging of the melanoma patient becomes more accurate, and treatment becomes more standardized and rational, because all those patients who have evidence of nodal disease can be identified so that they may benefit from more extensive surgery (formal node dissections) or adjuvant therapies. Based on these results, RT-PCR could be a powerful tool to detect micrometastatic melanoma.

Seasonal and Diel Abundance of Viruses and Occurrence of Lysogeny/Bacteriocinogeny in the Marine Environment

Abstract: To understand the role of viruses in the marine environment, it is important to know the factors affecting their temporal distribution and the abundance of lysogens. We therefore performed a seasonal and a diel study on viral distribution in Tampa Bay, Florida, USA, and detected the abundance of lysogens and bacteriocinogens amongst marine bacterial isolates from diverse marine environments. We investigated the distribution of viruses, bacterial direct counts, chlorophyll a (chl a), salinity and temperature during a 13 mo period in the Tampa Bay estuary. The results indicated that the viral population had a strong seasonal pattern with the highest concentrations (2.0 f 0.8 X 10') in the summer and lowest (4.8 k 1.4 X 106) in the winter Viral abundance was negatively correlated with salinity ( r = -0.8031, and positively correlated with chl a concentration (r = 0.725). A dlel study in a seawater mesocosm indcated that viral abundance did not vary on a diel rhythm, but rather peaked after a maximumin bacterial abundance and chl a. Dissolved DNA concentrations displayed diel rhythmicity, suggesting that viruses were not the main source of dissolved DNA. An estimation of the percentage of the bacterial standing stock lysed by viruses based on 4 h intervals ranged from 3.0 to 53.3 % per day. Screening bacterial isolates for the presence of inducible prophages indicated that 43 % were lysogens or bacteriocinogens, suggesting that lysogeny and bacteriocinogeny are common in the marine environment.

Methotrexate in rheumatoid arthritis. a five-year prospective multicenter study

Abstract: Objective To evaluate the efficacy and tolerability of oral methotrexate (MTX) in rheumatoid arthritis (RA) in a long-term prospective trial Methods One hundred twenty-three patients with RA who completed a 9-month multicenter randomized trial comparing MTX and auranofin enrolled in this 5-year prospective study of MTX Results Significant (P = 00001) improvement compared with baseline was noted in all clinical disease variables, functional status, and the Westergren erythrocyte sedimentation rate (ESR) “Marked improvement” occurred in 87 (71%) and 85 (69%) of the patients, respectively, in the joint pain/tenderness index and the joint swelling index at the last evaluable visit Forty-four patients (36%) withdrew during the study Eight (7%) withdrew due to lack of efficacy, and 8 (7%) due to adverse experiences, including 1 patient with cirrhosis At 5 years, 64% of patients were still taking MTX and completed the study Conclusion This large prospective study of long-term MTX treatment demonstrates sustained clinical response and improvement in the Westergren ESR and functional assessment scores, with an acceptable toxicity profile

Prevalence and percutaneous drainage of cysts of the sacral nerve root sheath (Tarlov cysts).

Abstract: PURPOSE To describe a percutaneous CT-guided method for drainage of perineurial (Tarlov) cysts, which are a cause of sciatica and low back pain, and to report the prevalence of these cysts within the population as detected by MR. METHODS Five hundred sequential lumbosacral spine MRs were evaluated for the presence of a perineurial cyst. Using CT-guided percutaneous drainage techniques, seven cysts were drained in five symptomatic patients. RESULTS Of the 500 sequential lumbosacral spine MRs, examinations from 23 patients showed perineurial cysts, a prevalence of 4.6%. Five patients (1%) were symptomatic from the cysts. After CT-guided percutaneous drainage, instant pain relief lasted from 3 weeks to 6 months without the risk or cost of spine surgery. CONCLUSIONS Lumbosacral perineurial cysts are common lesions that are usually asymptomatic but may cause pressure symptoms. Cyst puncture can alleviate the pain. Although the cysts repressurized and the patients9 symptoms returned in most cases, this technique seems to be a quick and simple way of at least attaining a pain-free interval and possibly a complete cure as occurred in one patient in this study.

Manganese intoxication and chronic liver failure

Abstract: Manganese intoxication and chronic liver failure are associated with strikingly similar clinical, imaging, and pathological abnormalities. As manganese is primarily cleared by the liver, inadequate elimination of manganese absorbed from the normal diet may lead to manganese overload in patients with liver disease. We report a significant elevation of blood manganese concentration in 3 patients with biopsy-proved hepatic cirrhosis who exhibited neurological dysfunction and characteristic abnormal signal hyperintensity in the globi pallidi and substantia nigra on T1-weighted magnetic resonance imaging. We speculate that manganese accumulation in the brain accounts for the magnetic resonance imaging abnormalities and contributes to neurological dysfunction in patients with liver disease.

MRI segmentation using fuzzy clustering techniques

Abstract: The authors' main contribution is to build upon their earlier efforts by expanding the tissue model concept to cover a brain volume. Furthermore, processing time is reduced and accuracy is enhanced by the use of knowledge propagation, where information derived from one slice is made available to succeeding slices as additional knowledge. The system is organized as follows. Each MR slice is initially segmented by an unsupervised fuzzy c-means clustering algorithm. Next, an expert system uses model-based recognition techniques to locate a landmark, called a focus-of attention tissue. Qualitative models of slices of brain tissue are defined and matched with their instances from imaged slices. If a significant deformation is detected in a tissue, the slice is classified to be abnormal and volume processing halts. Otherwise, the expert system locates the next focus-of-attention tissue, based on a hierarchy of expected tissues. This process is repeated until either a slice is classified as abnormal or all tissues of the slice are labeled. If the slice is determined to be abnormal, the entire volume is also considered abnormal and processing halts. Otherwise, the system will proceed to the next slice and repeat the classification steps until all slices that comprise the volume are processed. A rule-based expert system tool, CLIPS, is used to organize the system. Low level modules for image processing and high level modules for image analysis, all written in the C language, are called as actions from the right hand sides of the rules. The system described here is an attempt to provide completely automatic segmentation and labeling of normal volunteer brains. The absolute accuracy of the segmentations has not yet been rigorously established. The relative accuracy appears acceptable. Efforts have been made to segment an entire volume (rather than merging a set of segmented slices) using supervised pattern recognition techniques or unsupervised fuzzy clustering. However, there is sometimes enough data nonuniformity between slices to prevent satisfactory segmentation. >

Dietary Nucleotides: Cellular Immune, Intestinal and Hepatic System Effects

Abstract: Investigations with animals demonstrate that dietary nucleotides influence immune function. Restriction of dietary nucleotides in mice decreases several indices of cell-mediated immunity as well as resistance to challenge with Staphylococcus aureus or Candida albicans. Spleen cells of mice maintained on nucleotide-free diet produce less interleukin-2 and have lower natural killer cell cytotoxicity and macrophage activation than those of animals fed nucleotide-supplemented diets. In vivo lymphoproliferative response, macrophage phagocytic activity and expression of interleukin-2 receptor and lyt1 surface marker are also lower in animals fed nucleotide-free diets. At 2 mo of age, infants fed breast milk or nucleotide-supplemented infant formula exhibit increased natural killer cell activity compared with infants fed unsupplemented formula. Dietary nucleotide restriction in animals may also result in hepatic lipid accumulation and decreased mucosal height and gut wall thickness. Adenosine monophosphate, a mediator of hepatic and small bowel blood flow, may play a unique role among the nucleotides studied. In conclusion, de novo synthesis and salvage of nucleotides is a metabolically costly process. An exogenous source of nucleotides from the diet may optimize the function of rapidly dividing tissues, particularly when growth is rapid and the diet is low in nucleotides.

Portable pulse oximeter

Abstract: A diagnostic instrument for determining a cardiovascular system parameter. In one embodiment, the instrument takes the form of a portable pulse oximeter comprising a light to frequency converter (LFC) as a sensor. Also provided is a light to frequency converter comprising a photoresistor and capacitor in circuit communication with an inverting Schmitt trigger and configured such that the inverter generates a periodic electrical signal corresponding to the amount of electromagnetic radiation illuminating the photoresistor.

Processing of Eukaryotic Ribosomal RNA

Abstract: In summary, it can be argued that the understanding of eukaryotic rRNA processing is no less important than the understanding of mRNA maturation, since the capacity of a cell to carry out protein synthesis is controlled, in part, by the abundance of ribosomes. Processing of pre-rRNA is highly regulated, involving many cellular components acting either alone or as part of a complex. Some of these components are directly involved in the modification and cleavage of the precursor rRNA, while others direct the packaging of the rRNA into ribosome subunits. As is the case for pre-mRNA processing, snoRNPs are clearly involved in eukaryotic rRNA processing, and have been proposed to assemble with other proteins into at least one complex called a "processosome" (17), which carries out the ordered processing of the pre-rRNA and its assembly into ribosomes. The formation of a processing complex clearly makes possible the regulation required to coordinate the abundance of ribosomes with the physiological and developmental changes of a cell. It may be that eukaryotic rRNA processing is even more complex than pre-mRNA maturation, since pre-rRNA undergoes extensive nucleotide modification and is assembled into a complex structure called the ribosome. Undoubtedly, features of the eukaryotic rRNA-processing pathway have been conserved evolutionarily, and the genetic approach available in yeast research (6) should provide considerable knowledge that will be useful for other investigators working with higher eukaryotic systems. Interestingly, it was originally hoped that the extensive work and understanding of bacterial ribosome formation would provide a useful paradigm for the process in eukaryotes. However, although general features of ribosome structure and function are highly conserved between bacterial and eukaryotic systems, the basic strategy in ribosome biogenesis seems to be, for the most part, distinctly different. Thus, the detailed molecular mechanisms for rRNA processing in each kingdom will have to be independently deciphered in order to elucidate the features and regulation of this important process for cell survival.

Three peptides from the atrial natriuretic factor prohormone amino terminus lower blood pressure and produce diuresis, natriuresis, and/or kaliuresis in humans.

Abstract: BACKGROUND Three peptides consisting of amino acids 1-30, 31-67, and 79-98 of the 126-amino acid atrial natriuretic factor prohormone (proANF), which have blood pressure-lowering, diuretic, natriuretic, and/or kaliuretic properties in animals, were investigated to determine if they have similar properties in humans. METHODS AND RESULTS Thirty-six healthy, normotensive human volunteers (18 men and 18 women, ages 20 to 58 years) were divided into six similar groups based on age, sex, weight, blood pressure, and heart rate. After a 60-minute baseline period, 100 ng of proANFs 1-30, 31-67, 79-98, or ANF/kg body wt per minute was given intravenously for 60 minutes followed by a 3-hour postinfusion data collection period. Each of the atrial natriuretic peptides decreased systolic and diastolic blood pressures (P CONCLUSIONS ProANFs 1-30, 31-67, and 79-98, as well as ANF have significant blood pressure-lowering and diuretic properties. ProANFs 1-30 and 31-67 also have natriuretic properties in humans that are significantly (P

A multicenter double‐blind placebo‐controlled trial of pergolide as an adjunct to sinemet® in Parkinson's disease

Abstract: Three hundred and seventy-six subjects with advanced Parkinson's disease participated in a prospective, double-blind placebo-controlled study of the dopamine agonist pergolide mesylate as an adjunct to Sinemet. At 6 months, patients randomized to pergolide had a statistically significant improvement in total Parkinson's score, scores of activities of daily living, motor function, number of "off" hours, Hoehn and Yahr stage, and numerous parameters of parkinsonian function including bradykinesia, rigidity, gait, and dexterity. This benefit was obtained with the addition of a mean dose of 2.94 mg of pergolide, which permitted a 24.7% reduction in dose of levodopa. Adverse reactions were, for the most part, mild, reversible, and not of major clinical significance. No significant cardiac or electrocardiographic abnormalities were detected. This study demonstrates that pergolide mesylate, as an adjunct to levodopa, is an effective antiparkinsonian agent that provides clinical improvement while permitting a reduction in levodopa dose.

Bacterial heat shock proteins directly induce cytokine mRNA and interleukin-1 secretion in macrophage cultures.

Abstract: Bacterial heat shock proteins (hsp) have been shown to be important immunogens stimulating both T cells and B cells. However, little is known concerning the direct interactions between hsp and macrophages. In this study, we demonstrated that treatment of macrophage cultures with purified bacterial hsp, including Legionella pneumophila hsp60, Escherichia coli GroEL, Mycobacterium tuberculosis hsp70, Mycobacterium leprae hsp65, and Mycobacterium bovis BCG hsp65, increased the steady-state levels of cytokine mRNA for interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-6, tumor necrosis factor alpha, and granulocyte-macrophage colony-stimulating factor as well as supernatant IL-1 secretion. This effect was shown not to be due to contamination of the hsp preparations with bacterial lipopolysaccharide. However, not all hsp induced cytokines; M. tuberculosis hsp10 showed minimal activity in our study. These results suggest that bacterial hsp might modulate immunity by rapidly and directly increasing cytokine production in macrophages.

User Response Data: The Potential for Errors and Biases

Abstract: Surveys that require users to evaluate or make judgments about information systems and their effect on specific work activities can produce misleading results if respondents do not interpret or answer questions in the ways intended by the researcher. This paper provides a framework for understanding both the cognitive activities and the errors and biases in judgment that can result when users are asked to categorize a system, explain its effects, or predict their own future actions and preferences with respect to use of a system. Specific suggestions are offered for wording survey questions and response categories so as to elicit more precise and reliable responses. In addition, possible sources of systematic bias are discussed, using examples drawn from published IS research. Recommendations are made for further research aimed at better understanding how and to what extent judgment biases could affect the results of IS surveys.

Role of CD11a and CD11b in ischemic acute renal failure in rats

Abstract: Leukocytes, particularly neutrophils, have been implicated in ischemic-reperfusion organ injury (IRI). However, their role in kidney IRI is controversial. Leukocytes express the adhesion molecules ...

Visceral obesity and breast cancer risk

Abstract: Background. The risk for breast cancer and the sex hormone abnormalities noted in breast cancer patients have been demonstrated in women with upper body fat obesity. The objective of this study was to determine if the visceral component of upper body fat obesity was correlated with breast cancer risk. Methods. A case-control study of 40 consecutively enrolled women with breast cancer and 40 community based age, weight, and waist circumference-matched control subjects was conducted. The areas of visceral fat, subcutaneous fat, and total fat were measured using computed tomography at the 1, -4 vertebral body. Calculations of relative risk for breast cancer were based on these fat compartments. Results. Patients with breast cancer had a significantly greater visceral fat area (P = 0.01), visceral-to-to-tal-fat area ratio (VT ratio) (P 0.24 = 9.5) (P < 0.0001) and decreasing SV ratio (≥3.64 = 1.0; <3.64 = 8.5) (P = 0.0002). Conclusions. Visceral obesity, as assessed by computed tomography, was a significant risk factor for breast cancer in women matched for age, weight, and waist circumference. Comparing the VT ratio for both groups, breast cancer patients had 45% more visceral fat compared with matched control subjects. Cancer 1994; 74: 632-9

Homomeric rho 1 GABA channels: activation properties and domains.

Abstract: Expression of human rho 1 subunits in Xenopus laevis oocytes forms homomeric GABA-activated chloride channels with activation and pharmacological properties distinct from those of typical heteromeric GABA channels (e.g., alpha 1 beta 2 gamma 2). Here, we describe these rho 1 activation features and use site-directed mutagenesis to identify amino acids involved in GABA-mediated activation. In comparison to heteromeric GABA channels (alpha 1 beta 2 gamma 2), GABA channels comprised of rho 1 subunits are approximately 40-fold more sensitive to GABA, activate 8.3-fold more slowly (at a GABA concentration equal to their respective EC50S), do not desensitize with maintained agonist application, and close approximately 8-fold more slowly after agonist removal. Site-directed mutagenesis of rho 1 GABA channels has identified five amino acids (Y198, Y200, Y241, T244, and Y247) located between the N-terminal extracellular cysteine loop and first membrane spanning domain, that when conservatively mutated, significantly impaired GABA-mediated activation. These five residues are grouped in two domains that correspond in position to the putative agonist-binding domains previously identified for the beta 2 subunit of alpha 1 beta 2 gamma 2 GABA channels. Y198, T244, and Y247 correspond directly to crucial amino acids identified in the beta 2 subunit; Y200 and Y241 do not. These differences may account, in part, for the unique activation and pharmacological features of homomeric rho 1 GABA channels.