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PubMed2005

Using a module-based laboratory to incorporate inquiry into a large cell biology course.

Because cell biology has rapidly increased in breadth and depth, instructors are challenged not only to provide undergraduate science students with a strong, up-to-date foundation of knowledge, but also to engage them in the scientific process. To these ends, revision of the Cell Biology Lab course at the University of Wisconsin-La Crosse was undertaken to allow student involvement in experimental design, emphasize data collection and analysis, make connections to the "big picture," and increase student interest in the field. Multiweek laboratory modules were developed as a method to establish an inquiry-based learning environment. Each module utilizes relevant techniques to investigate one or more questions within the context of a fictional story, and there is a progression during the semester from more instructor-guided to more open-ended student investigation. An assessment tool was developed to evaluate student attitudes regarding their lab experience. Analysis of five semesters of data strongly supports the module format as a successful model for inquiry education by increasing student interest and improving attitude toward learning. In addition, student performance on inquiry-based assignments improved over the course of each semester, suggesting an improvement in inquiry-related skills.

Alkaline Phosphatase↗
PubMed1992

Analysis of responses to big endothelin in the hindquarters vascular bed of the cat.

OBJECTIVE: To investigate vascular responses to the endothelin-1 (ET-1) precursor, human big endothelin 1-38 (big ET), in the peripheral vascular bed of the cat. DESIGN: These studies were designed to investigate the hypothesis that bit ET is converted to an active peptide with properties similar to ET-1. SETTING: Hindquarters vascular bed of the cat under conditions of controlled bloodflow; changes in perfusion pressure reflect changes in vascular resistance. ANIMALS: Fifty-four adult mongrel cats. INTERVENTIONS: Big ET, ET-1, the peptidases chymotrypsin, pepsin and cathepsin-D, and the metalloprotease inhibitor phosphoramidon. MAIN RESULTS: Intra-arterial injections of big ET induced a slow-developing and sustained increase in hindquarters perfusion pressure which could be blocked by phosphoramidon. ET-1 (0.3 nmol), administered as a slow infusion over a 10-min period, produced a slowly developing increase in hindquarters perfusion pressure in a manner similar to that observed in response to injection of big ET. A bolus injection of ET-1 produced a biphasic response characterized by a transient decrease in pressure followed by an increase which was significantly greater in magnitude and more rapid in onset than the pressor response to big ET (0.3 nmol). After incubation of big ET with chymotrypsin, pepsin and cathepsin-D (each 5% weight/weight) for 30 mins at 37 degrees C, injection of activated big ET produced a biphasic response characteristic of the response to ET-1 with an initial transient decrease in pressure followed by a secondary increase in hindquarters perfusion pressure. CONCLUSIONS: Big ET produces a phosphoramidon-sensitive pressor response which is similar to that produced by an infusion of ET-1. These data suggest that chymotrypsin, pepsin and cathepsin-D can convert big ET to an active peptide which elicits a biphasic response similar to that produced by ET-1.

Animals↗
PubMed1989

A quantitative evaluation of sex differences in implicit personality theories.

An investigation is conducted into whether male and female perceivers hold substantially different implicit theories of personality. 24 male and 24 female subjects were asked to sort a set of 36 trait names into groups of similar traits. On the basis of these data, proximities between trait names and proximities between groupings (or partitions) were computed and subjected to a differential statistical analysis. Neither a global test for sex-specific groupings of trait names nor tests at the level of perceived pairwise trait relationships yielded significant differences. It is concluded that aggregation of sorting data over both male and female perceivers is warranted without too big a loss of information. On the methodological side, this paper demonstrates the feasibility of a quantitative approach to handling the problem of data aggregation in the context of studies using the sorting method as a data-gathering technique.

Adult↗
PubMed2005

Higher-order factors of the big five model of personality: a reanalysis of Digman (1997).

Based on the results from factor analyses conducted on 14 different data sets, Digman proposed a model of two higher-order factors, or metatraits, that subsumed the Big Five personality traits. In the current article, problems in Digman's analyses were explicated, and more appropriate analyses were then conducted using the same 14 correlation matrices from Digman's study. The resultant two-factor model produced improper solutions, poor model fit indices, or both, in almost all of the 14 data sets and thus raised serious doubts about the veracity of Digman's proposed model.

Factor Analysis, Statistical↗
PubMed2005

Uganda study found that death reduced HIV prevalence; did the public take home the wrong message?

Uganda has had a remarkable decline in HIV prevalence, and the question of what caused this decline is controversial. An intensive study of the Rakai region of Uganda from 1994 - 2003 found that much of the decreased prevalence resulted from death of people with HIV. But the incidence of new HIV infections was low throughout this study and did not change greatly, suggesting that the real cause of the success was a large reduction in new infections before the study began. The early data presented at the February 2005 Retroviruses conference also showed increasing use of condoms, and some backsliding on reducing the number of sexual partners. But neither change was big enough to greatly affect the incidence of new infections, at least in the aggregate data across the 50 villages studied. In summary, the big reduction in HIV prevalence occurred because of changes that happened before this study, not those measured within it. Therefore the new information does not contradict reduction in the number of sexual partners as a major cause of Uganda's success.

Adolescent↗
PubMed1991

Smooth muscle cells contain a factor responsible for decreasing big endothelin and endothelin-1 produced by cultured endothelial cells.

The production of big endothelin-1 (big ET-1) and its processing to endothelin (ET-1) were examined in cocultures of bovine pulmonary artery endothelial cells (BPECs) and human bronchiolar smooth muscle cells (HBSMCs). The BPECs produced immunologically reactive ET-1 (ir-ET-1) and big ET-1 (ir-big ET-1) that increased linearly in the cell culture media over a 72 h time course when confluent monolayers were incubated at 37 degrees C in serum-free media. HBSMCs maintained in serum-free media over a 72-h period did not produce any detectable ir-big ET-1 or ir-ET-1. After coculture of these two cell types for 24 h (the monolayers were physically separated), the culture medium contained no detectable ir-big ET-1 or ir-ET-1. When medium conditioned for 24 h with the HBSMCs was transferred to the BPEC monolayers, the accumulation rates of ET-1 and big ET-1 were attenuated 70 and 10%, respectively. When medium conditioned for 24 h with the BPECs was transferred to the HBSM cell monolayers, the amount of ir-ET-1 and ir-big ET-1 in the medium decreased greater than 90% over the next 24 h. Cellular binding and uptake could not account for this decrease as ascertained by quantitation of cellular levels of ET-1 and big ET-1. When conditioned medium from the HBSMCs was added to conditioned medium from the BPECs in a 1:1, 2:1, 3:1, 1:2, or 1:3 ratio (v/v) in the absence of cells, the amount of ET-1 or big ET-1 present in the EC medium did not decrease significantly over the following 24 h. These data imply that HBSMCs contain a factor that is responsible for decreasing the accumulation of ir-big ET-1 and ir-ET-1 in the cell culture media of BPECs. The data also suggest that the most likely mechanism for this effect is a factor that degrades BET-1 and ET-1 at different rates.

Animals↗
PubMed2000

Exact (spiral + circles) scan region-of-interest cone beam reconstruction via backprojection.

We present a (spiral + circles) scan cone beam reconstruction algorithm in which image reconstruction proceeds via backprojection in the object space. In principle, the algorithm can reconstruct sectional region-of-interest (ROI) in a long object. The approach is a generalization of the cone beam backprojection technique developed by Kudo and Saito in two aspects: the resource-demanding normalization step in the Kudo and Saito's algorithm is eliminated through the technique of data combination that we published earlier, and the elimination of the restriction that the detector be big enough to capture the entire cone beam projection of the ROI. Restricting the projection data to the appropriate angular range required by data combination can be accomplished by a masking process. Because of the simplification resulting from the elimination of the normalization step, the most time-consuming operations of the algorithm can be approximated by the efficient step of line-by-line ramp filtering the cone beam image in the direction of the scan path, plus a correction image. The correction image, which can be computed exactly, is needed because data combination is not properly matched at the mask boundary when ramp filtering is involved. Empirical two-dimensional (2-D) point spread function (PSF) is developed to improve matching with the correction image which is computed with finite samplings. The use of transition region to further improve matching is introduced. The results of testing the algorithm on simulated phantoms are presented.

Algorithms↗
PubMed2000

Hypoxia augments conversion of big-endothelin-1 and endothelin ET(B) receptor-mediated actions in rat lungs.

We have examined the effect of endothelin-1, sarafotoxin-6C, big-endothelin-1 and other agents on perfused lungs from chronically hypoxic rats. Increases in pulmonary perfusion pressure induced by big-endothelin-1, endothelin-1, phenylephrine and potassium chloride were enhanced in hypoxic lungs, while the constrictor action of sarafotoxin-6C was not increased. When basal pulmonary perfusion pressure was raised, low doses of endothelin-1 and sarafotoxin-6C produced decreases in pulmonary perfusion pressure which were significantly greater in chronically hypoxic lungs, whereas responses to sodium nitroprusside were unchanged. Endothelin ET(B) receptor-mediated bronchoconstrictor responses were also potentiated in hypoxic lungs, whereas responses to carbachol were not. In hypoxic lungs, conversion of big-endothelin-1 to endothelin-1 was significantly increased. These data provide evidence for a generalised increase in vasomotor activity in chronically hypoxic lungs, and a more selective increase in endothelin ET(B) receptor-mediated vasodilator and bronchoconstrictor responses. Hypoxia also augments the conversion of big-endothelin-1 to endothelin-1.

Animals↗
PubMed1997

Expression and localization of endothelin converting enzyme in rat vas deferens.

Endothelins (ETs) are a family of vasoconstrictor and mitogenic peptides originally isolated from the endothelial cells. Three isoforms of ET, namely ET-1, ET-2 and ET-3, are generated from their respective intermediate precursors big ETs through specific endoproteolytic cleavage by endothelin converting enzyme (ECE). Using reverse-transcription polymerase chain reaction (RT-PCR), we have isolated a cDNA encoding for ECE from both the prostatic and epididymal halves of rat vas deferens. In situ hybridization using digoxigenin-labeled ECE cDNA probe demonstrated that ECE mRNA is preferentially localized in the inner longitudinal smooth muscle layer adjacent to submucosa region of rat vas deferens. Both ET-1 and big ET-1 at 30 nM potentiated electrically stimulated contractile response of prostatic vas deferens. Pre-incubation of tissue with a metalloprotease ECE inhibitor phosphoramidon (10 microM) strongly inhibited the response to big ET-1, but not to ET-1. On the other hand, big ET-1 failed to elicit contractile response of epididymal vas deferens. Phosphoramidon alone did not affect both the basal and electrically stimulated contractile responses in vas deferens. These data indicate that the circulating ET-1 and its immediate precursor big ET-1 could differentially regulate smooth muscle contractions in the prostatic and epididymal vas deferens of the rat.

Animals↗
PubMed2006

Atmospheric monitoring at abandoned mercury mine sites in Asturias (NW Spain).

Mercury concentrations are usually significant in historic Hg mining districts all over the world, so the atmospheric environment is potentially affected. In Asturias, northern Spain, past mining operations have left a legacy of ruins and Hg-rich wastes, soils and sediments in abandoned sites. Total Hg concentrations in the ambient air of these abandoned mine sites have been investigated to evaluate the impact of the Hg emissions. This paper presents the synthesis of current knowledge about atmospheric Hg contents in the area of the abandoned Hg mining and smelting works at 'La Peña-El Terronal' and La Soterraña, located in Mieres and Pola de Lena districts, respectively, both within the Caudal River basin. It was found that average atmospheric Hg concentrations are higher than the background level in the area (0.1 microg Nm(-3)), reaching up to 203.7 microg Nm(-3) at 0.2 m above the ground level, close to the old smelting chimney at El Terronal mine site. Data suggest that past Hg mining activities have big influences on the increased Hg concentrations around abandoned sites and that atmospheric transfer is a major pathway for Hg cycling in these environments.

Air Pollutants↗
PubMedDate not supplied

[Appropriate use of the mechanisms for the fixation of hip prostheses].

OBJECTIVE: To evaluate the appropriateness of the use of fixation mechanisms for hip replacement in patients with osteoarthritis or prosthesis revision, using explicit criteria. METHODS: Following the RAND appropriateness method, it was carried out a revision of the bibliography and was created a list of 12 indications for osteoarthritis and 32 for the revision. A panel of 27 experts, all of them traumatologists, punctuated the degree of appropriateness for each indication in a scale of 1 (completely inappropriate) up to 9 (completely appropriate). According to the median of the punctuations and the agreement level, each indication was classified as appropriate, uncertain or inappropriate. The data of ten public hospitals of medium and big size of the Basque Service of Health-Osakidetza, were picked up and the developed criteria were applied to the evaluated interventions. RESULTS: 831 osteoarthritis interventions and 349 revisions were evaluated. Of the 136 interventions in which the prosthesis used was cemented, in two thirds its use was considered appropriate. The cementless prosthesis was used more frequently (77%) and in most of the cases (94%) it was considered appropriate according to the criteria of the panel. Of the 68 acetabular revisions in which cemented prosthesis was used, in 85% of them the use of cementless mechanism was recommended. However, of the 134 interventions that used cementless, the panel agreed on 94%. Similar results happened with the femoral revision. CONCLUSIONS: The study offers some recommendations on the use of the cemented and cementless prosthesis, based on the work of a panel of experts. Once applied, the criteria of the panel a certain level of uncertain use is observed.

Age Factors↗
PubMed1998

Hepatic lacI and cII mutation in transgenic (lambdaLIZ) rats treated with dimethylnitrosamine.

The recent introduction of a transgenic rat in vivo mutation assay is a much needed supplement to the transgenic mouse models and offers the tools necessary for collecting target tissue specific genotoxicity data in this species. The utility of the Big Blue(R) rat for the detection of in vivo mutations was investigated by studying spontaneous and dimethylnitrosamine (DMN)-induced hepatic mutations. High molecular weight DNA isolated from Big Blue(R) rat livers typically yielded good transgene rescue efficiency of up to 5x105 plaque forming units per packaging reaction. DMN, when administered by oral gavage at dose levels of 0.2, 0.6, 2.0, and 6.0 mg kg-1 day-1, induced up to a 4.5-fold increase in mutations at the highest dose level. There was no apparent difference between the lacI vs. cII target genes of the shuttle vector in either the background or DMN-induced mutant frequencies. These results suggest that the transgenic rat model is a useful tool for studying potential genotoxicity in target organs and, with further validation, the selectable cII target could be an attractive alternative to the conventional lacI color screening method for the detection of mutations in the lambdaLIZ shuttle vector.

Animals↗
PubMed1995

Motor affliction of the L5 nerve root in lumbar nerve root compression syndromes.

STUDY DESIGN: From a prospective and consecutive study on degenerative lumbar spine disorders containing 416 patients, all patients with a severely reduced or absent strength of the extensor hallucis longus muscle (n = 35) before surgery were identified. OBJECTIVES: The incidence, diagnosis, and recovery after surgery of patients with L5 root compression syndromes and a severely reduced or absent power before surgery of the big toe extensor was evaluated. SUMMARY OF BACKGROUND DATA: The L5 root is commonly involved in disc herniation and central and lateral spinal stenosis. Whether motor recovery occurs after root decompression is not fully known. METHODS: All patients underwent a conventional radiologic evaluation before surgery including one or more myelography, computed tomography scan, and magnetic resonance imaging. At examination before surgery, extensor hallucis longus-power was graded as normal, reduced, or severely reduced/absent, and the latter group is presented here. Surgical findings were registered. Clinical investigation was performed after 4, 12-, and 24-month follow-up periods. RESULTS: A pronounced extensor hallucis longus paresis was seen in disc herniation in 20 of 187 patients, in lateral spinal stenosis in 10 of 122 patients, and central spinal stenosis 5 of 107 patients. Improvement of the paresis after surgery was equally common in disc herniation (15 of 20 patients) and lateral spinal stenosis (7 of 10 patients). Complete restitution was more common in disc herniation. None of the five patients with central spinal stenosis improved concerning paresis at the follow-up period. Improvement was most common during the first 4 months after surgery. No correlation between age or preoperative symptom duration and recovery was noted in either group. CONCLUSION: The incidence of pronounced extensor hallucis longus paresis in lumbar nerve root compression varied between 5-11%. Recovery after surgery was common in disc herniation and lateral spinal stenosis but did not occur in central stenosis. Complete recovery was most common in disc herniation, and recovery occurred mainly during the first 4 months after surgery.

Adult↗
PubMed1976

Evidence for higher proportion of "little" growth hormone with increased radioreceptor activity in acromegalic plasma.

Plasma growth hormone (GH) from both normal and acromegalic patients comprises multiple immunoreactive components that can be separated by G-100 Sephadex gel filtration and measured by radioimmunoassay (RIA) and radioreceptor assay (RRA). The higher molecular weight immunoreactive components, from both normal and acromegalic subjects, have a lower RRA/RIA than does the lower molecular weight "little" GH component. The "little" GH component comprises a higher proportion of the total immunoreactive GH in acromegalic plasma than in normal plasma whether the data are expressed only in terms of the "big" and "little" components (89 vs. 71%), or as a function of total immunoreactive GH (76 vs. 55%), or whether the plasma is obtained in the basal or stimulated state for the acromegalic patients. When the RRA/RIA x 100 is determined for the isolated "little" component, the acromegalic has a significantly greater ratio than the normal (110 vs. 75%). We conclude that acromegalic plasma contains a higher proportion of the more radioreceptor active "little" GH component than does the normal and, in addition, that the "little" component from the acromegalic is more radioreceptor-active than the normal.

Acromegaly↗
PubMed1985

Plasma clearance of intravenously administered pituitary human growth hormone: gel filtration studies of heterogeneous components.

Both pituitary and plasma human GH (hGH) comprise heterogeneous components, exhibiting similar patterns when gel filtered on Sephadex G-100. To determine at what rate the components are cleared from the circulation, blood was obtained at specific intervals following a bolus injection of pituitary hGH in hypopituitary patients. Each sample was gel filtered to determine its component profile of RIA values, which, when plotted vs. the time interval it represented, yielded a means of monitoring its disappearance from the plasma. Total hGH was cleared with a t 1/2 of 21.5 min, the little component was cleared at 19.0 min, the big component was cleared at 26.5 min, and the pre-big component was cleared at 45 min. These data indicate that the larger the hGH component, the longer it takes to be cleared from the plasma.

Adolescent↗
PubMed2005

The hefty penalty on marriage facing many households with children.

Over the past seventy years Congress has enacted dozens of tax and transfer programs, giving little if any attention to the marriage subsidies and penalties that they inadvertently impose. Although the programs affect both rich and poor Americans, the penalties fall most heavily on low- or moderate-income households with children. In this article, Adam Carasso and Eugene Steuerle review important penalties and subsidies, explain how they work, and help fill a big research gap by beginning to provide comprehensive data on the size of the penalties and subsidies arising from all public programs considered together. Marriage penalties arise because of the combination of variable U.S. tax rates and joint, rather than individual, filing by married couples for benefits and taxes. If graduated taxes were accompanied by individual filing or if all income and transfers were taxed at a flat rate, there would be no marriage penalties. Specifically, the penalties are a result of policymakers' efforts to achieve the goal of progressivity--giving greater tax and welfare benefits to those with lower income--while trying to keep down program costs. Thus benefits in transfer programs fall, sometimes steeply, as households earn more income. Combining the direct tax rate in the tax code and the benefit reduction rates in the transfer system can result in extremely high effective marginal tax rates for many low- to moderate-income families-rates far higher than those of families earning over 90,000 dollars. These high rates lead to the marriage penalties because additional income brought into a household by marriage thus causes other benefits to be reduced or lost altogether. In extreme cases, households can lose a dollar or more for every dollar earned. In recent years lawmakers have begun to try to reduce marriage penalties, primarily by reforming welfare and cutting taxes, but huge penalties remain. The authors offer several options for reducing or eliminating the marriage penalty and recommend two in particular. The first is to set a maximum marginal tax rate for lower-income individuals, similar to the maximum rate set for highest-income individuals. The second is to provide individual wage subsidies to lower-income earners, so that such workers who marry can combine their income with that of their spouse without incurring penalties.

Adult↗
PubMed2001

Effect of short photoperiod on organ growth kinetics and serum hormone profile in pullets of domestic fowl, Gallus gallus domesticus.

Effect of short photoperiod (SP; LD 6:18) treatment on serum hormone profile and growth rate of adrenal, thyroid, ovary, oviduct, liver and lymphoid organ was studied in rearing pullets (RIR breed) of 1 to day 90 old. Body weight and growth index of SP pullets were lesser as compared to pullets reared under LD 12:12. Except for ovary (recorded marginal increment), weights and growth indices of thyroid, adrenal and oviduct decreased under SP. Weight of liver and lymphoid organs was higher at 30 and 90 days, in SP pullets as compared to LD 12:12. Histometric data suggested that the transition from small to big follicles was slow in ovary of SP pullets, and also reduced follicular atresia was noted in SP pullets. Except for higher corticosterone level at 30 days and higher progesterone level at 30 and 60 days, relative levels of all the hormones at all other ages were lower in SP pullets. In general, the present observations suggested intraovarian changes in pullets exposed to SP.

Animals↗
PubMedDate not supplied

[Substance abuse and psychiatric disorders in homeless youth].

In contrast to other countries as USA, Australia and some European countries there are no German studies concerning psychiatric disorders in runaway and homeless children and adolescents. Although the presence of street youths faces a big problem, there is a deficit of empirical data among this group for the planning of more efficient differential programming. In this pilot study we investigated male and female street adolescents among ICD-10 respectively DSM-IV criteria. The goal of this study was to build gender-specific hypotheses and to investigate the applicability and practicability of the standardised diagnostic instruments assessing psychiatric and substance-related disorders.

Adolescent↗