Showing papers by "Wayne State University published in 1994"

Maps from two interspecific backcross DNA panels available as a community genetic mapping resource

Abstract: We established two mouse interspecific backcross DNA panels, one containing 94 N2 animals from the cross (C57BL/6J × Mus spretus)F1 × C57BL/6J, and another from 94 N2 animals from the reciprocal backcross (C57BL/6J × SPRET/Ei)F1 × SPRET/Ei. We prepared large quantities of DNA from most tissues of each animal to create a community resource of interspecific backcross DNA for use by laboratories interested in mapping loci in the mouse. Initial characterization of the genetic maps of both panels has been completed. We used MIT SSLP markers, proviral loci, and several other sequence-defined genes to anchor our maps to other published maps. The BSB panel map (from the backcross to C57BL/6J) contains 215 loci and is anchored by 45 SSLP and 32 gene sequence loci. The BSS panel map (from the backcross to SPRET/Ei) contains 451 loci and is anchored by 49 SSLP loci, 43 proviral loci, and 60 gene sequence loci. To obtain a high density of markers, we used motif-primed PCR to “fingerprint” the panel DNAs. We constructed two maps, each representing one of the two panels. All new loci can be located with a high degree of certainty on the maps at current marker density. Segregation patterns in these data reveal several examples of transmission ratio distortion and permit analysis of the distribution of crossovers on individual chromosomes.

Friction-Induced Vibration, Chatter, Squeal, and Chaos—Part I: Mechanics of Contact and Friction

Abstract: Friction force between sliding surfaces arises due to varied and complex mechanisms and can be responsible for undesirable dynamic characteristics in many mechanical systems. Controversies over the theory of friction have been reported in the literature. Friction laws are phenomenological in charcacter since they are based on observable and measurable quantities. The mechanics of contact and friction in metal-metal and elastomer-metal contact surfaces are reviewed. Unfortunately, there is no satisfactory method capable of determining or measuring the area of contact between sliding bodies. Both dry friction and lubricated friction are considered. The modeling of the friction force in mechanical systems depends on several factors. These include the material properties and geometry of the sliding surfaces, surface roughness, surface chemistry, sliding speed, temperature, and normal load. Other factors include the effect of normal and tangential vibrations on the static friction. Here the static friction is considered as a special case of kinetic friction. This background is essential for dynamicists studying friction-induced vibration, chatter, squeal and chaos topics which will be presented in the second part.

The impact of subtype, frequency, chronicity, and severity of child maltreatment on social competence and behavior problems

Abstract: This investigation examined the impact of dimensions within maltreatment such as the severity, frequency, chronicity, and subtypes of maltreatment and their relationship with child outcome. Children between the ages of 5 and 11 who participated in a summer camp program were assessed on their social competence, behavior problems, and peers ratings of cooperation, disruption, and initiation of aggression. The 235 participants were all from low-socioeconomic status families; 145 children were from families with documented histories of child maltreatment, whereas 90 of the children had no record of maltreatment. The study found that severity of the maltreatment, the frequency of Child Protective Services reports, and the interaction between severity and frequency were significant predictors of children's functioning. Additionally, the chronicity of the maltreatment in the family significantly predicted peer ratings of aggression. Subtype differences emerged as well, with children in the sexual abuse group being more socially competent than other maltreated children, and children in the physical abuse group having more behavior problems than nonmaltreated children. Regression analyses with cooccurrence of multiple subtypes of maltreatment indicated that physical neglect, physical abuse, and sexual abuse made significant unique contributions in predicting child outcomes. The advantages of exploring multiple dimensions within maltreatment, the necessity of developing better operational definitions of these dimensions, and social policy implications of the findings are discussed.

Percutaneous Balloon Valvuloplasty Compared with Open Surgical Commissurotomy for Mitral Stenosis

Abstract: Background Percutaneous balloon mitral valvuloplasty has been proposed as an alternative to open surgical commissurotomy for the treatment of rheumatic mitral-valve stenosis. Methods We enrolled 60 patients with severe mitral stenosis and favorable valvular anatomy in a prospective, randomized trial comparing the two procedures. All patients underwent cardiac catheterization before the procedure and one week, six months, and three years thereafter. Hemodynamic data were analyzed by investigators who were blinded to the patients' treatment assignments. Results Mitral-valve areas improved initially in both groups, from a mean (±SD) of 0.9 ±0.3 cm2 to 2.1 ±0.6 cm2 in the balloon-valvuloplasty group (30 patients; P<0.01) and from 0.9 ±0.3 cm2 to 2.0 ±0.6 cm2 in the surgical group (30 patients; P<0.001). Although improvement was maintained in both groups, mitral-valve areas were greater in the patients in the balloon-valvuloplasty group at three years (2.4 ±0.6 cm2, vs. 1.8 ±0.4 cm2 in the surgery group; P<0.0...

Pericellular pH Affects Distribution and Secretion of Cathepsin B in Malignant Cells

Abstract: Redistribution of lysosomes to the cell surface and secretion of lysosomal proteases appear to be general phenomena in cells that participate in local proteolysis In the present study, we have determined whether malignant progression affects the intracellular distribution and secretion of the lysosomal protease cathepsin B in three model systems, each of which consists of cell pairs that differ in their degree of malignancy The intracellular distribution of vesicles staining for cathepsin B was evaluated by immunofluorescent microscopy and the secretion of cathepsin B was evaluated by two complementary techniques: stopped assays of activity secreted into culture media; and continuous assays of activity secreted from viable (> or = 95%) cells growing on coverslips We observed that the intracellular distribution of cathepsin B+ vesicles was more peripheral in the cells of higher malignancy in all three model systems and that active cathepsin B was secreted constitutively from these cells Because an acidic pericellular pH has been shown to induce translocation of lysosomes in macrophages and fibroblasts, we evaluated the intracellular distribution of cathepsin B+ vesicles and secretion of cathepsin B in cell pairs incubated at slightly acidic pH Acidic pericellular pH induced a redistribution of cathepsin B+ vesicles toward the cell periphery In the more malignant cells, this resulted with time in reduced intracellular staining for cathepsin B and enhanced secretion of active cathepsin B Translocation and secretion of cathepsin B were dependent on a functional microtubular system Both the redistribution of cathepsin B+ vesicles toward the cell surface induced by acidic pH and the constitutive and acidic pH-induced secretion of active cathepsin B could be inhibited by microtubule poisons and stabilizers We suggest that the redistribution of active cathepsin B to the surface of malignant cells and its secretion may facilitate invasion of these cells

Diagnosability of discrete event systems and its applications

Abstract: As man-made systems become more and more complex, diagnostics of component failures is no longer an easy task that can be performed based on experience and intuition. Therefore, it is important to develop a systematic approach to diagnostic problems. Diagnostics can be done either on-line or off-line. By on-line diagnostics, we mean diagnostics performed while the system to be diagnosed is in normal operation. On the other hand, in off-line diagnostics, the system is not in normal operation. We will study both on-line and off-line diagnostics in this paper and identify main features and differences of these two types of diagnostics. We will also introduce the concept of diagnosability and study its properties, all in the framework of discrete event systems. This study is motivated by diagnostic problems in the automotive industry and we will emphasize its applications.

Cloning and characterization of zona pellucida genes and cDNAs from a variety of mammalian species: The ZPA, ZPB and ZPC gene families

Abstract: Full length zona pellucida cDNAs from cat, dog and pig that are homologous to the ZP2/rc75 genes from mouse, human and rabbit, a full length zona pellucida cDNA from cat and a gene and full length cDNA from human that are homologous to the rc55/ZP3 alpha genes from rabbit and pig, and full length zona pellucida cDNAs from cat, cow, dog, pig and rabbit that are homologous to the ZP3 genes from mouse, hamster, human and marmoset have been cloned and characterized. The members of these gene families are herein referred to as ZPA, ZPB and ZPC genes to avoid the confusion that currently exists in the zona pellucida of nomenclature. This report is the first to describe the presence all three major zona pellucida genes within individual mammalian species. Within the ZPA, ZPB and ZPC gene families, the DNA and deduced amino acid sequences are highly homologous to each other, and are most homologous between members of the same order within the class mammalia. These results imply that all or most mammalian species express the ZPA, ZPB and ZPC proteins, which form the zona pellucida layer surrounding the oocyte.

Urban Regime Theory in Comparative Perspective

Abstract: The urban literature has devoted increasing attention to cross-national comparison of urban change and governance. What is lacking, however, is the development of conceptual frameworks that are ade...

17 beta-Estradiol attenuates voltage-dependent Ca2+ currents in A7r5 vascular smooth muscle cell line

Abstract: Previous studies have shown that 17 beta-estradiol (beta-E2) has a direct acute inhibitory effect on vascular smooth muscle (VSM) contraction. To investigate the mechanisms underlying this phenomenon, we utilized whole cell patch-clamping techniques to study effects of beta-E2 on voltage-dependent Ca2+ channels in cultured VSM cells (VSMC). T- and L-type Ca2+ currents were characterized with ramp and pulse protocols in A7r5 cultured VSMC. T-type current, inactivated in < 100 ms, was reduced by Ba2+ and was comparatively little affected by isradipine. L-type current required higher voltages to activate, inactivated slowly, was greatly increased by Ba2+, and could be completely inhibited by 5 microM isradipine. beta-E2 (10 microM) significantly reduced peak L-type Ba2+ current and T-type Ca2+ current within 1-2 min, whereas alpha E2 (a hormonally inactive isomer of estradiol) caused significantly less reduction in both types of current. Vehicle (0.1% ethanol) had no significant effect on either current. The...

Screening for Pregnancy Risk-Drinking

Abstract: The efficacy of alcohol screening questionnaires, the TWEAK, T-ACE, NET, MAST, and CAGE, in detecting periconceptional risk-drinking, > or = 1 oz absolute alcohol/day, was investigated in 4743 African-American women attending an inner-city prenatal clinic who had reported ever drinking. Sensitivity, specificity, positive predictive value, efficiency, follow-up rates, and receiver operating characteristics of the questionnaires were examined to compare the overall effectiveness of the questionnaires and their performance at cut-points defining positive scores ranging from 1 to 3. Relatively little difference between TWEAK, T-ACE, and MAST was seen in the receiver operating characteristic accuracy indices; NET and CAGE lagged behind. Sensitivity/specificity scores for the two questionnaires most sensitive at cut-point 1 were TWEAK (87/72) and T-ACE (83/75). At cut-point 2, sensitivity was optimized with respect to specificity; TWEAK (79/83) was significantly more sensitive than T-ACE (70/85; p = 0.002). At cut-point 3, the two most sensitive tests were MAST (61/92) and TWEAK (59/94). In general, measures of merit were not greatly affected by the time between conception and the administration of the screens. Screening was most sensitive for women interviewed during the first 15 weeks of pregnancy; risk-drinkers tended to delay entry into prenatal care, increasing positive predictive values associated with screening later in pregnancy. This study confirms the utility, when screening for risk-drinking during pregnancy, of brief questionnaires that assess alcohol intake indirectly by asking women about their tolerance to alcohol's effects, psychological consequences of drinking, and significant others' concern about their drinking. It validates T-ACE and provides preliminary data indicating that TWEAK may outperform T-ACE.

Growth factor localization in choroidal neovascular membranes of age-related macular degeneration.

Abstract: Purpose. Because several polypeptide growth factors are known to influence capillary endothelial cell mitogenesis, the authors investigated the presence of some of these molecules in choroidal neovascular membranes (CNVMs) removed surgically from human subjects with age-related macular degeneration (ARMD). Methods. The authors performed immunoelectron microscopic studies on surgically removed submacular CNVMs from nine subjects with ARMD and from one subject with ARMD whose eye was studied after death. These were compared with retinal pigment epithelial (RPE) and choroidal tissue from eight normal subjects whose eyes were received after death and one received after massive trauma. Results. RPE cells from the CNVMs were strongly immunoreactive for acidic and basic fibroblast growth factor (aFGF and bFGF) and for transforming growth factor @ (TGF/3). Some of the immunoreactivity was intracytoplasmic, but most was intralysosomal. In addition, some choriocapillary endothelial cells located close to the RPE layer in these CNVMs were immunopositive for bFGF and for FGF receptor. Reaction product for these two substances was located at regular intervals along the endothelial plasma membrane on both the anteluminal and the luminal side of the cells, suggesting a physiological reaction between the growth factor and its receptor. Choriocapillary endothelial cells deeper within the stroma were unreactive to bFGF and FGF receptor antibodies. There was little immunoreactivity for the growth factors in RPE or choriocapillary endothelial cells from normal eyes. The aFGF and bFGF immunoreactivity was highly specific because aFGF positivity was abolished when the antibody was incubated with 10~ 6 M aFGF but not a with the same concentration of bFGF, whereas bFGF immunoreactivity was abolished by incubation of the antibody with bFGF but not with aFGF. RPE cells from normal eyes and from eyes affected by ARMD showed strong cytoplasmic immunoreactivity to antibodies for cytoplasmic retinaldehyde-binding protein and superoxide dismutase and weak reactivity to antibodies for vimentin. Conclusions. These results are consistent with the hypothesis that one or both FGFs are causally related to the development of choroidal neovascularization. The authors have reported similar observations in experimental choroidal neovascularization in pigmented rats after red krypton laser photocoagulation. TGF/? may serve to modulate the effects of these mitogens. The authors suggest that growth factor production is induced in RPE cells after physical or chemical damage. Because of the damage to these cells, FGF molecules can be released from the cells despite the absence of a "signal sequence" in the DNA coding for FGF production. Invest Ophthalmol Vis Sci. 1994;35:3178-3188.

Simulations of Gas-Phase Chemical Reactions: Applications to SN2 Nucleophilic Substitution.

Abstract: Computer simulations and animations of the motion of atoms as a chemical reaction proceeds give a detailed picture of how the reaction occurs at a microscopic level This information is particularly useful for testing the accuracy of statistical models, which are used to calculate various attributes of chemical reactions Such simulations and animations, in concert with experimental and ab initio studies, have begun to provide a microscopic picture of the intimate details of a particular class of gas-phase ion-molecule bimolecular reactions known as SN2 nucleophilic substitution In these reactions, a nucleophile is displaced from a molecule by another nucleophile The dynamical model of SN2 reactions that emerges from the computer studies, and its relation to statistical theories, is discussed here

Influences of canopy architecture on relationships between various vegetation indices and LAI and Fpar: A computer simulation

Abstract: Vegetation Indices (VIs) are often used to estimate important biophysical parameters, like LAI and Fpar, from vegetation canopy reflectance data. In this study, a three‐dimensional model (Diana) is utilized to generate architecturally realistic tree and crop canopies in various development stages and to calculate bidirectional reflectance factors in the principal plane. We investigate the influence of various factors like soil brightness, optical properties of canopy elements, leaf angle distribution, spacing distance between plants and solar and view geometries on relationships between VI and Fpar, LAI and percentage ground cover (GC) in order to determine optimal VI and viewing conditions for the estimation of Fpar and LAI/GC. These simulation studies suggest that: (1) in most cases, Vis using off‐nadir reflectances are more informative and useful than those based on nadir reflectances; (2) the optimal VI and sun/view geometries are usually different for inferring different parameters, dependin...

Two long QT syndrome loci map to chromosomes 3 and 7 with evidence for further heterogeneity

Abstract: Cardiac arrhythmias cause sudden death in 300,000 United States citizens every year. In this study, we describe two new loci for an inherited cardiac arrhythmia, long QT syndrome (LQT). In 1991 we reported linkage of LQT to chromosome 11p15.5. In this study we demonstrate further linkage to D7S483 in nine families with a combined lod score of 19.41 and to D3S1100 in three families with a combined score of 6.72. These findings localize major LQT genes to chromosomes 7q35-36 and 3p21-24, respectively. Linkage to any known locus was excluded in three families indicating that additional heterogeneity exists. Proteins encoded by different LQT genes may interact to modulate cardiac repolarization and arrhythmia risk.

Increased gelatinase A (MMP-2) and cathepsin B activity in invasive tumor regions of human colon cancer samples.

Abstract: Gelatinase A (MMP-2) and cathepsin B are proteinases which have been proposed to participate in human tumor invasion and metastasis. Precise quantitation of the activity of these enzymes in invading tumors has not been previously described. We utilized a novel tissue microdissection technique to determine levels of enzyme activity in specific microscopic areas of invasive human colon cancer. Tissue specimens smaller than one high power field can be extracted from the samples and analyzed. Increased levels of pro-enzyme and active enzyme forms of gelatinase A (MMP-2) and increased cathepsin B activity were localized in regions of tumor invasion as compared with a matched number of normal epithelial cells from the same patient. Levels of progelatinase B (MMP-9) were also increased in the tumors; however, we did not observe activation of this enzyme. To investigate the mechanism of gelatinase A activation, we amplified DNA of specific microdissected tumor cell populations using polymerase chain reaction. We did not detect a mutation in the activation locus of the enzyme in any of the tumors studied, which suggests that activation may be due to up-regulation of a tumor-associated gelatinase A activating species. Microdissection of frozen tissue sections may prove valuable in the study of proteinases in human tumor invasion as well as in the detection of genetic alterations in human cancers.

Development of A Model for Self-Determination:

Abstract: SELF-DETERMINATION is rapidly gaining attention and acceptance within the disability field, particularly with respect to the transition from school to adulthood movement. This is occurring as persons with disabilities, their families, educators and service providers are questioning the passive stereotypes and roles often assigned to persons with disabilities which are in direct conflict with typical expectations of adults. Recent legislation reinforced the importance of self-determination for students with disabilities. The Individuals With Disabilities Education

A political theory of intergovernmental grants

Abstract: This paper formulates a political theory of intergovernmental grants. A model of vote-maximizing federal politicians is developed. Grants are assumed to buy the support of state voters and the ‘political capital or resources’ of state politicians and interest groups which can be used to further increase the support of state voters for the federal politician. The model is tested for 49 states. Similarity of party affiliation between federal and state politicians and the size of the Democrat majority in the state legislature increases the per capita dollar amount of grants made to a state. Likewise, increases in both the size of the state bureaucracy and union membership lead to greater grants for a state. Over time, the importance of interest groups (bureaucracy and unions) has increased relative to political groups (state politicians).

Response of Resistant Idiopathic Thrombocytopenic Purpura to Pulsed High-Dose Dexamethasone Therapy

Abstract: Background Most patients with chronic idiopathic thrombocytopenic purpura have a response to corticosteroids or intravenous immune globulin, but improvement is often transitory. Splenectomy may provide only a short-term benefit. Because pulsed high-dose therapy with potent synthetic corticosteroids is inexpensive, well tolerated, and effective in patients with secretory B-cell neoplasms, a similar regimen was examined for its efficacy in patients with chronic idiopathic thrombocytopenic purpura that was resistant to other treatments. Methods Ten consecutively referred patients who had persistent symptomatic idiopathic thrombocytopenic purpura after undergoing at least two standard therapies were treated with six cycles of dexamethasone (40 mg per day for 4 sequential days every 28 days). Results All patients had increased platelet counts (mean [±SD] count before treatment, 12,000 ±8200 per cubic millimeter; after treatment, 248,000 ±130,000 per cubic millimeter). The platelet counts remained above 100,000...