Penalized gaussian process regression and classification for high-dimensional nonlinear data

The model based on Gaussian process (GP) prior and a kernel covariance function can be used to fit nonlinear data with multidimensional covariates. It has been used as a flexible nonparametric approach for curve fitting, classification, clustering, and other statistical problems, and has been widely applied to deal with complex nonlinear systems in many different areas particularly in machine learning. However, it is a challenging problem when the model is used for the large-scale data sets and high-dimensional data, for example, for the meat data discussed in this article that have 100 highly correlated covariates. For such data, it suffers from large variance of parameter estimation and high predictive errors, and numerically, it suffers from unstable computation. In this article, penalized likelihood framework will be applied to the model based on GPs. Different penalties will be investigated, and their ability in application given to suit the characteristics of GP models will be discussed. The asymptotic properties will also be discussed with the relevant proofs. Several applications to real biomechanical and bioinformatics data sets will be reported.

Non-contrast cardiac computed tomography can accurately detect chronic myocardial infarction: Validation study

BACKGROUND

This study evaluates whether non-contrast cardiac computed tomography (CCT) can detect chronic myocardial infarction (MI) in patients with irreversible perfusion defects on nuclear myocardial perfusion imaging (MPI).

METHODS

One hundred twenty-two symptomatic patients with irreversible perfusion defect (N = 62) or normal MPI (N = 60) underwent coronary artery calcium (CAC) scanning. MI on these non-contrast CCTs was visually detected based on the hypo-attenuation areas (dark) in the myocardium and corresponding Hounsfield units (HU) were measured.

RESULTS

Non-contrast CCT accurately detected MI in 57 patients with irreversible perfusion defect on MPI, yielding a sensitivity of 92%, specificity of 72%, negative predictive value (NPV) of 90%, and a positive predictive value (PPV) of 77%. On a per myocardial region analysis, non-contrast CT showed a sensitivity of 70%, specificity of 85%, NPV of 91%, and a PPV of 57%. The ROC curve showed that the optimal cutoff value of LV myocardium HU to predict MI on non-contrast CCT was 21.7 with a sensitivity of 97.4% and specificity of 99.7%.

CONCLUSION

Non-contrast CCT has an excellent agreement with MPI in detecting chronic MI. This study highlights a novel clinical utility of non-contrast CCT in addition to assessment of overall burden of atherosclerosis measured by CAC.

A single molecule Kondo switch: multistability of tetracyanoethylene on Cu(111)

Single tetracyanoethyelene (TCNE) molecules on Cu(111) are reversibly switched among five states by applying voltage pulses with the tip of a scanning tunneling microscope. A pronounced Kondo resonance in tunneling spectroscopy indicates that one of the states is magnetic. Side bands of the Kondo resonance appear at energies which correspond to inter- and intramolecular vibrational modes. Density functional theory suggests that molecular deformation changes the occupancy in TCNE's molecular orbitals, thus producing the magnetic state.

Polarization-modulated rectification at ferroelectric surfaces

By correlating room temperature conductive atomic force microscopy with low temperature electrostatic force microscopy images of the same sample region, we demonstrate that nanoscale electric conduction between a sharp tip and the surface of ferroelectric HoMnO3 is intrinsically modulated by the polarization of ferroelectric domains. Conductance spectra reveal that the electric conduction is described by polarization-induced Schottky-like rectification at low bias, but dominated by a space-charge limited conduction mechanism at high bias. Our observation demonstrates visualization of ferroelectric domain structure by electric conduction, which may be used for nondestructive readout of nanoscale ferroelectric memories and/or ferroelectric sensors.

Insulating interlocked ferroelectric and structural antiphase domain walls in multiferroic YMnO3

Hexagonal YMnO(3) shows a unique improper ferroelectricity induced by structural trimerization. Extensive research on this system is primarily due to its candidacy for ferroelectric memory as well as the intriguing coexistence of ferroelectricity and magnetism. Despite this research, the true ferroelectric domain structure and its relationship with structural domains have never been revealed. Using transmission electron microscopy and conductive atomic force microscopy, we observed an intriguing conductive 'cloverleaf' pattern of six domains emerging from one point--all distinctly characterized by polarization orientation and structural antiphase relationships. In addition, we discovered that the ferroelectric domain walls and structural antiphase boundaries are mutually locked and this strong locking results in incomplete poling even when large electric fields are applied. Furthermore, the locked walls are found to be insulating, which seems consistent with the surprising result that the ferroelectric state is more conducting than the paraelectric state. These fascinating results reveal the rich physics of the hexagonal system with a truly semiconducting bandgap where structural trimerization, ferroelectricity, magnetism and charge conduction are intricately coupled.

277 ESTABLISHMENT OF EMBRYONIC STEM CELL LINES DERIVED FROM A EGFP-TRANSGENIC MOUSE AND THEIR SURVIVAL IN THE COCHLEA OF C57BL/6 MICE

Embryonic stem (ES) cells isolated from inner cell mass cells of blastocyst-stage embryos are capable of differentiating into various cell lineages. Transplantation of these cells may potentially be a treatment for many degenerative diseases. Such cell therapy has often been tested using allografts of ES cells in mice. However, it has been difficult to locate transplanted ES cells and to avoid the rejection of allogeneic ES cells by the host. The aims of this study were to establish ES cell lines ubiquitously expressing enhanced green fluorescent protein (EGFP) and to test survival of ES cells in allografts into the cochlea of inbred C57BL/6 mice. Nine hatched blastocysts collected from a C57BL/6-green mouse that ubiquitously expresses transgene EGFP were plated onto an inactivated STO feeder layer. Two putative ES-like colonies were obtained from the plated blastocysts, and repeated subculture of these colonies produced two cell lines expressing EGFP. The cell lines possessed typical characteristics of ES cells, including densely packed colonies of the cells with prominent nucleoli, a high nuclear-cytoplasmic ratio, and high alkaline phosphatase activity. In suspension culture, these cells formed simple and cystic embryoid bodies. Undifferentiated EGFP-transgenic ES cells (106 cells per mouse) were injected into the cochlea of five C57BL/6 mice deafened by gentamycin treatment. Although no behavioral changes were noticed until four weeks after the transplantation, histological study revealed that grafted cells survived in the scala media of all injected mice. Incorporation of the cells expressing EGFP into the host was found along the auditory nerve fibers close to the organ of Corti. Such incorporation was also discovered in the area of the spiral ganglion neurons, cochlear sensory epithelia, and stria vascularis. Morphology and size of the cells varied depending on their sites of incorporation. The results from the present study demonstrate that, due to their survival in transplantation without allogeneic rejection as well as ubiquitous and stable expression of EGFP, ES cells from an EGFP-transgenic mouse may be a useful means of studying cell therapy.

Identification of ras targets using a genetic approach

The Sevenless receptor tyrosine kinase is required for the development of the R7 photoreceptor cell in the Drosophila eye. Several components of the Sevenless signal transduction pathway have been identified in genetic screens for enhancers/suppressors of the sevenless phenotype. These studies suggest that activation of Sevenless leads to stimulation of Ras1 activity, whereas Gap1 appears to act as a negative regulator of the pathway. Inactivation of the Gap1 locus causes transformation of non-neuronal cone cells into supernumerary R7 cells. This same mutant phenotype is observed when activated Ras1 is expressed under the control of the sevenless promoter. While studies in other organisms have demonstrated a role for ras gene products in signal transduction, the effectors of Ras activity have not yet been identified. We are carrying out genetic screens for enhancers and suppressors of the Gap1 and activated Ras1 phenotypes in the hope of identifying genes encoding some of these effectors. We are conducting chemical mutagenesis screens and have also screened existing collections of P element lines. A molecular characterization of the most promising mutations is in progress.

Clinical response of quetiapine in rapid cycling manic bipolar patients and lactate level changes in proton magnetic resonance spectroscopy

The aim of the current study was to evaluate the relationship between quetiapine's effect on the improvement of mood symptoms in bipolar patients and brain metabolite level changes as measured by proton magnetic resonance spectroscopy ((1)H-MRS). Rapid cycling bipolar patients in the manic state were recruited and treated with quetiapine for 12 weeks. Clinical assessment was performed using the Young Mania Rating Scale (YMRS), the 17-item Hamilton Depression Rating Scale (HDRS) and the Clinical Global Impression-Severity scale (CGI-S) at baseline and weekly intervals during the 12-week period. In order to evaluate metabolite level changes over time, (1)H-MRS scans were acquired at baseline and week 12. There were significant reductions in YMRS scores (by 43.0%), HDRS scores (by 27.5%) and CGI-S score (by 44.6%) over the 12 week-period. Lactate levels significantly decreased over the 12-week study period (22.4%). This change in lactate levels was more prominent in quetiapine responders than in non-responders. Additionally, there was a positive correlation between changes in lactate levels and those in YMRS scores (r=0.52, p=0.003). Our findings suggest that quetiapine's antimanic and antidepressant efficacy in patients with rapid cycling bipolar disorder may potentially be related to decreased lactate levels in frontal regions of the brain.

Simple and regioselective bromination of 5,6-disubstituted-indan-1-ones with Br2 under acidic and basic conditions

Bromination of 5,6-dimethoxyindan-1-one with Br(2) in acetic acid at room temperature produced exclusively the corresponding 2,4-dibromo compound in 95% yield. Reaction of 5,6-dimethoxyindan-1-one with Br(2) in the presence of KOH, K(2)CO(3) or Cs(2)CO(3 )at ~0 degrees C( )gave the monobrominated product 4-bromo-5,6-dimethoxyindan-3-one in 79%, 81% and 67% yield, respectively. 5,6-Dihydroxyindan-1-one was dibrominated on the aromatic ring affording 4,7-dibromo-5,6-dihydroxyindan-1-one both in acetic acid at room temperature and in the presence of KOH at ~0 degrees C. 5,6-Difluoroindan-1-one and 1-indanone were alpha-monobrominated in acetic acid and alpha,alpha-dibrominated under KOH conditions at room temperature.

A novel class of highly potent, selective, and non-peptidic inhibitor of Ras farnesyltransferase (FTase)

Design, synthesis and structure-activity relationship of a class of aryl pyrroles as farnesyltransferase inhibitors are described. In vitro and in vivo evaluation of a panel of these inhibitors led to identification of 2 (LB42908) as a highly potent (IC(50)=0.9 nM against H-Ras and 2.4 nM against K-Ras) antitumor agent that is currently undergoing preclinical studies.

The DNA replication-related element (DRE)-DRE-binding factor (DREF) system may be involved in the expression of the Drosophila melanogaster TBP gene

The TATA box binding protein (TBP) is a general transcription factor required for initiation by all three eukaryotic RNA polymerases. Previously, we found that the promoter region of the Drosophila melanogaster TBP gene contains three sequences similar to the DNA replication-related element (DRE) (5'-TATCGATA). In the present study, we found that the DRE-like sequences are also present in the promoter of the Drosophila virilis TBP gene, suggesting a role for these sequences in TBP expression. Band mobility shift assays revealed that oligonucleotides containing sequences similar to the DRE of D. melanogaster TBP gene promoter form specific complexes with a factor in a Kc cell nuclear extract and with recombinant DRE-binding factor (DREF). Furthermore, these complexes were either supershifted or diminished by monoclonal antibodies to DREF. Transient luciferase assays demonstrated that induction of mutations in two DRE-related sequences at positions -223 and -63 resulted in an extensive reduction of promoter activity. Thus, the DRE-DREF system appears to be involved in the expression of the D. melanogaster TBP gene.

Total pelvic exenteration and reconstruction for locally invasive recurrent sarcoma of the perineum

Extensive primary tumors and locally recurrent tumors of the pelvis or perineum are difficult to manage. We describe the techniques necessary to perform total pelvic exenteration with en bloc resection of the perineum and genitalia for treatment of recurrent sarcoma of the perineum. Wide excision of the sarcoma with negative margins can be achieved by resecting the inferior portion of the pubic symphysis. An absorbable mesh sling may be used to suspend the small bowel above the pelvis, facilitating postoperative radiation. A catheterizable continent urinary reservoir avoids the necessity of two stomas and improves quality of life. Adequate tissue coverage can be attained by myocutaneous gracilis flaps that promote wound healing.

Urinary free beta hCG, beta core fragment and total oestriol as markers of Down syndrome in the second trimester of pregnancy

In a study of 69 random urine samples from cases of Down syndrome and 405 samples from unaffected pregnancies, we have assessed the value of various candidate markers that have been proposed as tools for screening for Down syndrome. We found that the marker urine free beta hCG in Down syndrome had a median MoM of 3.53 (95 per cent confidence interval 2.48-4.68) and at a 5 per cent cut-off would have identified 49 per cent (34/69) of cases. Urine beta core had a median MoM of 4.95 (3.87-8.62) and at a 5 per cent cut-off would have identified 39 per cent (27/69) of cases. Total oestriol had a median MoM of 0.65 (0.55-0.80) and at a 5 per cent cut-off would have identified 35 per cent (24/69) of cases. In conjunction with maternal age, the modelled detection rate increased to 55.8 per cent for free beta hCG, 49.8 per cent for beta core and 48.8 per cent for total oestriol. In combination free beta hCG, total oestriol and maternal age would have detected 68 per cent of cases for a 5 per cent false-positive rate. Using analyte ratios to obviate the need to correct for urine dilution in our study (rather than correcting to a fixed creatinine concentration) was not shown to be as effective as correcting using urine creatinine. Urine markers on the whole are unlikely to be of practical screening value considering the 85 per cent to 90 per cent detection rates achievable in the first trimester using a combination of ultrasound and maternal serum biochemistry.

Extended outpatient rehabilitation: its influence on symptom frequency, fatigue, and functional status for persons with progressive multiple sclerosis

OBJECTIVE

To determine the influence of an extended outpatient rehabilitation program on symptom frequency, fatigue, and functional status for persons with multiple sclerosis (MS).

DESIGN

Nonequivalent pretest/posttest control-group design, with posttest 1 year after initial assessment. Multiple regression analysis and analysis of covariance were used to control for symptom severity at the initial assessment and comorbid factors including depression, cognitive function, and social interaction. Effect sizes (ES) provided a descriptive measure of the change in outcomes.

SETTING

Outpatient multidisciplinary rehabilitation clinic.

PATIENTS

Forty-six patients with definite chronic progressive MS; 20 received treatment and 26 were in a nontreatment comparison group ("waiting list").

INTERVENTION

Rehabilitation services for 5 hours, 1 day per week, over 1 year.

MAIN OUTCOME MEASURES

The MS-Related Symptom Checklist composite score, fatigue frequency, and selected items from the Rehabilitation Institute of Chicago Functional Assessment Scale.

RESULTS

Receiving treatment was a significant predictor of reduced symptom frequency (partial r2 = .26) at the 1-year follow-up. The ES adjusted for baseline values indicated substantial reductions in symptom frequency for the treatment group (EStreatment = .27 vs ESwaitlist = -.32). Fatigue was significantly reduced at the time of follow-up for the treatment group compared with the waiting list group (EStreatment = .46 vs ESwaitlist = -.20). There were no statistically significant differences among groups regarding functional status, but there appeared to be less loss of functional status in the treatment group compared with the waiting list group (EStreatment = -.07 vs ESwaitlist = -.70).

CONCLUSIONS

An extended outpatient rehabilitation program for persons with definite progressive MS appears to effectively reduce fatigue and the severity of other symptoms associated with MS.

Characteristic ground-reaction forces in baseball pitching

Overhand throwing requires contributions from and interaction between all limb segments. Most previous investigations have concentrated on the throwing arm itself, yet poor mechanics at the arm may originate in the lower extremities. Multicomponent ground-reaction forces of both the push-off and landing limbs were measured in six collegiate and one high school level baseball pitchers. Full body kinematics were simultaneously recorded to correlate phases in the pitching cycle with the force data. Pitchers were found to generate shear forces of 0.35 body weight in the direction of the pitch with the push-off leg and to resist forces of 0.72 body weight with the landing leg. Wrist velocity was found to correlate highly with increased leg drive. This study validates the clinical impression that the lower extremity is an important contributor to the throwing motion. Based on this study, strengthening of the lower extremities could be inferred to be important both to enhance performance and to avoid injury.

Health-related quality of life for patients with progressive multiple sclerosis: influence of rehabilitation

BACKGROUND AND PURPOSE

The health-related quality of life of patients with multiple sclerosis (MS) is an important aspect of care outcome. The purpose of this study was to compare health-related quality of life between patients who received weekly comprehensive outpatient rehabilitation for 1 year and a group that did not receive rehabilitation.

SUBJECTS

Twelve patients receiving outpatient care for chronic progressive MS (mean age = 44.5 years, SD = 11.6) were compared with 19 similar patients (mean age = 49.2 years, SD = 9.2) on a waiting list who were not receiving outpatient care.

METHODS

A pretest-posttest longitudinal design was used to descriptively compare outcome measures. Multivariate regression analyses were used to determine which variables, controlled for baseline health status and other relevant patient characteristics, were related to the best outcomes at the time of the 1-year follow-up.

RESULTS

The treatment group showed improvements in six health status measures on the Rand 36-Item Health Survey 1.0 (SF-36) that were not improved in the wait-listed group. Outpatient treatment was the sole predictor of positive outcome for energy/fatigue (partial R2 = .43) and change in general health (partial R2 = .19). In addition, the treatment group was associated with a positive outcome (together with other independent variables) in the domains of social function and social support.

CONCLUSION AND DISCUSSION

Patients with chronic progressive forms of MS appear to derive benefits from an ongoing comprehensive outpatient rehabilitation program. [Di Fabio RP, Choi T, Soderberg J, Hansen CR. Health-related quality of life for patients with progressive multiple sclerosis: influence of rehabilitation.

CENP-E is an essential kinetochore motor in maturing oocytes and is masked during mos-dependent, cell cycle arrest at metaphase II

CENP-E, a kinesin-like protein that is known to associate with kinetochores during all phases of mitotic chromosome movement, is shown here to be a component of meiotic kinetochores as well. CENP-E is detected at kinetochores during metaphase I in both mice and frogs, and, as in mitosis, is relocalized to the midbody during telophase. CENP-E function is essential for meiosis I because injection of an antibody to CENP-E into mouse oocytes in prophase completely prevented progression of those oocytes past metaphase I. Beyond this, CENP-E is modified or masked during the natural, Mos-dependent, cell cycle arrest that occurs at metaphase II, although it is readily detectable at the kinetochores in metaphase II oocytes derived from mos-deficient (MOS-/-) mice that fail to arrest at metaphase II. This must reflect a masking of some CENP-E epitopes, not the absence of CENP-E, in meiosis II because a different polyclonal antibody raised to the tail of CENP-E detects CENP-E at kinetochores of metaphase II-arrested eggs and because CENP-E reappears in telophase of mouse oocytes activated in the absence of protein synthesis.

The Mos/mitogen-activated protein kinase (MAPK) pathway regulates the size and degradation of the first polar body in maturing mouse oocytes

Mos is an upstream activator of mitogen-activated protein kinase (MAPK) and, in mouse oocytes, is responsible for metaphase II arrest. This activity has been likened to its function in Xenopus oocytes as a component of cytostatic factor. Thus, Mos-deficient female mice (MOS-/-) are less fertile and oocytes derived from these animals fail to arrest at metaphase II and undergo parthenogenetic activation [Colledge, W. H., Carlton, M. B. L., Udy, C. B. & Evans, M. J. (1994) Nature (London) 370, 65-68 and Hashimoto, N., Watanabe, N., Furuta. Y., Tamemoto, B., Sagata, N., Yokoyama, M., Okazaki, K., Nagayoshi, M., Takeda, N., Ikawa, Y. & Aizawa, S. (1994) Nature (London) 370, 68-71]. Here we show that maturing MOS-/- oocytes fail to activate MAPK throughout meiosis, while p34cdc2 kinase activity is normal until late in metaphase II when it decreases prematurely. Phenotypically, the first meiotic division of MOS-/- oocytes frequently resembles mitotic cleavage or produces an abnormally large polar body. In these oocytes, the spindle shape is altered and the spindle fails to translocate to the cortex, leading to the establishment of an altered cleavage plane. Moreover, the first polar body persists instead of degrading and sometimes undergoes an additional cleavage, thereby providing conditions for parthenogenesis. These studies identify meiotic spindle formation and programmed degradation of the first polar body as new and important roles for the Mos/MAPK pathway.

Mos/mitogen-activated protein kinase can induce early meiotic phenotypes in the absence of maturation-promoting factor: a novel system for analyzing spindle formation during meiosis I

Mitogen-activated protein kinase (MAPK) is selectively activated by injecting either mos or MAPK kinase (mek) RNA into immature mouse oocytes maintained in the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). IBMX arrests oocyte maturation, but Mos (or MEK) overexpression overrides this block. Under these conditions, meiosis I is significantly prolonged, and MAPK becomes fully activated in the absence of p34cdc2 kinase or maturation-promoting factor. In these oocytes, large openings form in the germinal vesicle adjacent to condensing chromatin, and microtubule arrays, which stain for both MAPK and centrosomal proteins, nucleate from these regions. Maturation-promoting factor activation occurs later, concomitant with germinal vesicle breakdown, the contraction of the microtubule arrays into a precursor of the spindle, and the redistribution of the centrosomal proteins into the newly forming spindle poles. These studies define important new functions for the Mos/MAPK cascade in mouse oocyte maturation and, under these conditions, reveal novel detail of the early stages of oocyte meiosis I.

Abnormal centrosome amplification in the absence of p53

The centrosome plays a vital role in mitotic fidelity, ensuring establishment of bipolar spindles and balanced chromosome segregation. Centrosome duplication occurs only once during the cell cycle and is therefore highly regulated. Here, it is shown that in mouse embryonic fibroblasts (MEFs) lacking the p53 tumor suppressor protein, multiple copies of functionally competent centrosomes are generated during a single cell cycle. In contrast, MEFs prepared from normal mice or mice deficient in the retinoblastoma tumor suppressor gene product do not display these abnormalities. The abnormally amplified centrosomes profoundly affect mitotic fidelity, resulting in unequal segregation of chromosomes. These observations implicate p53 in the regulation of centrosome duplication and suggest one possible mechanism by which the loss of p53 may cause genetic instability.

Notational analysis on game strategy used by the world's top male squash players in international competition

The purpose of this study was to provide a profile of the competition strategy used by the world's top squash players at the international level and provide recommendations for other players to improve their playing strategy. A total of 10 matches including three in round one, the four quarter finals, the two semi-finals, and the final of the 1993 Hong Kong Squash Open were filmed using a 3-CDD video camera. The tournament was played under the North American scoring system. Notational analysis which is based on frame by frame video analysis was used to categorize a player's motion. The frequency of each stroke, and the success or failure rate of each stroke were recorded. Shots were classified as "effective", "ineffective", "winning" and "losing" shots and the analysis demonstrated that 70.28% were "effective", 19.86% were "ineffective", 5.37% were "winning" and 4.48% were "losing" shots. The mean number of shots per game was 252.09. The order of priority using different kinds of strokes in matches were as follows: drive (length) (60.79%), drop (17.91%), volley (11.79%), boast (4.80%), and lob (4.72%). The results of this study show that the "pressure and attack game" was the most important strategy for the world's top squash players in producing winning performances. Also identified are the strokes and the strategies which should be practiced to improve performance. This method of notational analysis can be utilized to evaluate the strengths and weaknesses of players at all levels of competition.

Caregivers of frail elderly and medically fragile children: perceptions of ability to continue to provide home health care

The purposes of this study were to compare the characteristics and support systems of caregivers of frail elderly and medically fragile children and to determine what factors discriminated between caregivers who could (and could not) continue to provide home health care. Caregivers of children were significantly more likely (chi 2 = 52.30)2), p = < .0000) to report that they were managing OK than caregivers of frail elderly. They also reported receiving more support and assistance from formal and informal sources, although in general, less than 30% of the caregivers received any help. Five variables (Mental impairment of the elder, poor physical and mental health of the caregiver, high monthly caregiving-related expenses, and use of paid in-home assistance) explained 35% of the variance between caregivers of frail elderly who were managing OK and those who were unable to continue to manage. Six variables (physical and mental impairment of the child, physical health of the caregiver, feeling like there were no alternative providers, time demand and lack of assistance from others) explained 26.57% of the variance between caregivers of children who were managing OK and those who were unable to continue to manage. The findings suggest that a strong objective stressor, combined with a lack of personal and social resources are associated with caregivers' perceptions that they cannot continue to manage home health care.

A deficiency in the mechanism for p34cdc2 protein kinase activation in mouse embryos arrested at 2-cell stage

Mouse embryos of the ddY strain fertilized in vitro undergo the first cleavage to the 2-cell stage but not the second cleavage even 45 hr after insemination (2-cell block). We examined the phosphorylation state of p34cdc2 and histone H1 kinase activity in mouse 2-cell embryos to investigate the relationship of p34cdc2 with 2-cell block. In the first mitotic cell cycle, the amount of phosphorylated forms of p34cdc2, which were detected as the bands of retarded mobility on SDS-PAGE followed by immunoblotting with anti-p34cdc2 antibody, increased during interphase and abruptly decreased at M phase. Concomitant with this dephosphorylation, histone H1 kinase activity was increased. After the embryos cleaved to the 2-cell stage, the amounts of phosphorylated forms of p34cdc2 increased up to 33 hr after insemination. However, the activation of histone H1 kinase did not occur and the states of phosphorylation of p34cdc2 did not show any significant changes until 45 hr. In contrast, 2-cell embryos of B6C3F1 mice, which do not show a 2-cell block and develop normally to blastocysts in vitro, exhibit the dephosphorylation of p34cdc2 and an increase in histone H1 kinase activity between 31 and 45 hr after insemination. When the ddY mouse embryos arrested at the 2-cell stage were treated with okadaic acid, an inhibitor of protein phosphatases 1 and 2A, the dephosphorylation of p34cdc2 occurred and histone H1 kinase activity increased. The chromosomes of these embryos stained with 4',6'-diamidino-2-phenylindole revealed the initiation of condensation. These results suggest that 2-cell-blocked embryos contain enough p34cdc2 to induce mitotic events but the protein remains in a latent form.

Activation of p34cdc2 protein kinase activity in meiotic and mitotic cell cycles in mouse oocytes and embryos

p34cdc2 protein kinase is a universal regulator of M-phase in eukaryotic cell cycle. To investigate the regulation of meiotic and mitotic cell cycle in mammals, we examined the changes in phosphorylation states of p34cdc2 and its histone H1 kinase activity in mouse oocytes and embryos. We showed that p34cdc2 has three different migrating bands (referred to as upper, middle and lower bands) on SDS-PAGE followed by immunoblotting with anti-PSTAIR antibody, and that the upper and middle bands are phosphorylated forms since these two bands shifted to the lower one by alkaline phosphatase treatment. In meiotic cell cycle, only germinal vesicle (GV) stage oocytes had the three forms. The phosphorylated forms decreased gradually in oocytes up to 2 h after isolation from follicles, and thereafter the phosphorylation states did not change significantly until metaphase II. However, the histone H1 kinase activity oscillated, being activated at the first and second metaphase in meiosis and inactivated at the time of the first polar body extrusion. These results suggest that changes in phosphorylation states of p34cdc2 triggered its activation at the first metaphase, but not inactivation and reactivation at the first and second metaphase, respectively. In mitotic cell cycle, phosphorylated forms appeared at 4 h after insemination, increased greatly just before metaphase, and were dephosphorylated in metaphase. Histone H1 kinase activity was high only at metaphase. This kinase activation is probably triggered by dephosphorylation of p34cdc2.

A generic intron increases gene expression in transgenic mice

To investigate the role of splicing in the regulation of gene expression, we have generated transgenic mice carrying the human histone H4 promoter linked to the bacterial gene for chloramphenicol acetyltransferase (CAT), with or without a heterologous intron in the transcription unit. We found that CAT activity is 5- to 300-fold higher when the transgene incorporates a hybrid intron than with an analogous transgene precisely deleted for the intervening sequences. This hybrid intron, consisting of an adenovirus splice donor and an immunoglobulin G splice acceptor, stimulated expression in a broad range of tissues in the animal. Although the presence of the hybrid intron increased the frequency of transgenics with significant CAT activity, it did not affect the integration site-dependent variation commonly seen in transgene expression. To determine whether the enhancement is a general outcome of splicing or is dependent on the particular intron, we also produced equivalent transgenics carrying the widely used simian virus 40 small-t intron. We found that the hybrid intron is significantly more effective in elevating transgene expression. Our results suggest that inclusion of the generic intron in cDNA constructs may be valuable in achieving high levels of expression in transgenic mice.

Barriers and motivators to prenatal care among low-income women

Substantial evidence exists which links prenatal care to improved birth outcomes. However, low-income and nonwhite women in the United States, who are at greatest risk for poor birth outcomes, continue to receive the poorest prenatal care. The purpose of this study was to identify and compare barriers and motivators to prenatal care among women who lived in low-income census tracts. The stratified sample included recently delivered white, black and American Indian women who received adequate, intermediate, and inadequate prenatal care. Interviews were conducted which focused primarily on the women's perceptions of problems in obtaining prenatal care and getting to appointments. Results indicated that women with inadequate care identified a greater number of barriers and perceived them as more severe. Psychosocial, structural, and socio-demographic factors were the major barriers, while the mother's beliefs and support from others were important motivators. The predictive power of selected barrier variables was examined by a regression analysis. These variables accounted for 50% of the variance in prenatal care use. The results affirm the complexity of prenatal care participation behavior among low-income women and the dominant influence of psychosocial factors. Comprehensive, coordinated and multidisciplinary outreach and services which address psychosocial and structural barriers are needed to improve prenatal care for low-income women.

Providing access to home care for disabled children: Minnesota's Medicaid model waiver program

Home care programs for severely disabled, usually technology-dependent, children got a boost in 1981 when the Federal Government gave States permission to use Medicaid to fund home care under the Medicaid model home- and community-based waiver (2176). The model waiver program was unique because it eliminated the bias toward hospitalization by waiving parental income and assets when determining eligibility for children cared for at home and by allowing Medicaid to cover needed home care services. In 1985 Minnesota received Federal approval for the model waiver, and the results are detailed in this report. Although the waiver could provide funding for up to 50 children, after 2 years only 24 children had received approval. Stringent and complex eligibility criteria acted as barriers to accessing the model waiver. In addition, the interaction between the waiver and the State's health care system contributed to inconsistencies in eligibility. This interaction demonstrates the difficulty of administering publicly funded programs in the current health care environment. Recommendations are made for adjusting criteria for eligibility in the waiver program. Unresolved problems facing technology-dependent children on home care programs are discussed.

Perinatal lethal osteogenesis imperfecta in transgenic mice bearing an engineered mutant pro-alpha 1(I) collagen gene

Substitutions of single glycine residues of alpha 1(I) collagen have previously been associated with the inherited disease osteogenesis imperfecta type II. Transgenic mice bearing a mutant alpha 1(I) collagen gene into which specific glycine substitutions have been engineered show a dominant lethal phenotype characteristic of the human disease, and demonstrate that as little as 10% mutant gene expression can disrupt normal collagen function.

Effects on nurse retention. An experiment with scheduling

Four randomly selected nursing groups were assigned to three experimental groups and one control group to test the relative impact of three experimental nursing schedules, using a before-after design. The three experimental treatments were straight shifts; regular schedule but with unlimited requests for changes; and individual station-designed schedules. Before treatment, score differences between the experimental and control groups were limited to one of 36 highly reliable scales specifically constructed and pretested to gauge effects of scheduling. This single difference was judged not to be significantly related to experimental outcomes. Because of a poor job market situation, retention was not affected significantly by any of the three treatments, but root causes of turnover were. Results of the experiment showed that individual station-designed schedules triggered the most changes that favor retention. In contrast, the other two treatments unexpectedly increased nurses' own sense of marketability and reduced teamwork among nurses. Reasons accounting for the results are discussed in the text.

Hospital cost savings: resembling business

Hospitals, like other employers, offer health care benefits to their employees. Cost savings can be realized when hospitals offer packages that resemble those provided by business employers. Business packages explain variance in cost savings more than employee characteristics do.

Impact of environment on state university hospital performance. An explanatory model

This article, by means of a path model, shows the impact of environment on state university hospital performance. The state environment is shown to affect systematically the intensity of local competition, the reputation of the medical school, the financial independence of the parent university, the allocation of indigent care dollars, the nature of governance and management, and the performance of the hospital. Results show that while certain environments are predictably more supportive of universities and university hospitals, these environments tend also to attract health care competition. Competition is shown to pressure hospitals into greater efficiency, but competition is shown also to hurt viability. But a hospital management that pays attention to the hospital environment is shown to help both efficiency and viability. The model explains respectively 37% and 46% of the variance in hospital efficiency and viability.