Genetic screen for suppressors of increased silencing in rpd3 mutants in Saccharomyces cerevisiae identifies a potential role for H3K4 methylation.

Several studies have identified the paradoxical phenotype of increased heterochromatic gene silencing at specific loci that results from deletion or mutation of the histone deacetylase (HDAC) gene RPD3. To further understand this phenomenon, we conducted a genetic screen for suppressors of this extended silencing phenotype at the HMR locus in Saccharomyces cerevisiae. Most of the mutations that suppressed extended HMR silencing in rpd3 mutants without completely abolishing silencing were identified in the histone H3 lysine 4 methylation (H3K4me) pathway, specifically in SET1, BRE1, and BRE2. These second-site mutations retained normal HMR silencing, therefore, appear to be specific for the rpd3Δ extended silencing phenotype. As an initial assessment of the role of H3K4 methylation in extended silencing, we rule out some of the known mechanisms of Set1p/H3K4me mediated gene repression by HST1, HOS2, and HST3 encoded HDACs. Interestingly, we demonstrate that the RNA Polymerase III complex remains bound and active at the HMR-tDNA in rpd3 mutants despite silencing extending beyond the normal barrier. We discuss these results as they relate to the interplay among different chromatin-modifying enzyme functions and the importance of further study of this enigmatic phenomenon.

Use of cryopreserved cells for enabling greater flexibility in compound profiling.

Measurement of intracellular calcium release following agonist challenge within cells expressing the relevant membrane protein is a commonly used format to derive structure-activity relationship (SAR) data within a compound profiling assay. The Fluorometric Imaging Plate Reader (FLIPR) has become the gold standard for this purpose. FLIPR traditionally uses cells that are maintained in continuous culture for compound profiling of iterative chemistry campaigns. This supply dictates that assays can only be run on 4 of 5 weekdays, or alternative cell culture machinery is required such that plating can occur remotely at the weekend. The data reported here demonstrate that high-quality compound profiling data can be generated from the use of cryopreserved cells and that these cells can also be plated at various densities to generate equivalent data between 24 and 72 h post-plating. Hence, the authors report a method that allows data generation throughout the week and without the requirement of highly automated cell culture or continuous culture.

A meningococcal vaccination campaign on a university campus: vaccination rates and factors in nonparticipation.

OBJECTIVES: This study was undertaken to determine an accurate vaccination rate and identify factors influencing nonvaccination in a meningococcal vaccination campaign on a Connecticut university campus in May 1993. METHODS: Vaccination and student data were merged to determine demographic factors associated with nonvaccination. A case-control study examined reasons for nonvaccination. RESULTS: The estimated vaccination rate for students returning to the campus was 93%. Lower rates occurred among older students, students living off campus, graduate and nondegree students, and married students. Perceived poor access to the vaccination center was the strongest predictor of nonvaccination. CONCLUSIONS: Higher vaccination rates may be achieved by specifically targeting students who live off campus and by providing multiple vaccination sites with extended hours.

An exploratory study of the relationship between alternative therapies, functional status, and symptom severity among people with multiple sclerosis.

Roy's Adaptation Model guided an exploratory study of the association of alternative therapies with functional status and symptoms in people with multiple sclerosis (MS). Data were collected from 16 volunteers by a telephone-administered interview schedule and a mailed questionnaire. All 16 respondents reported seeking traditional medical treatment and at least 1 alternative therapy (mode = 3, range = 1-9). The correlation between the number of alternative therapies and functional status was -.42; the greater the number of therapies used by the respondents, the lower their functional status. Qualitative data analysis revealed that functional status was enhanced by beneficial effects of specific alternative therapies, pacing oneself, changing the perception of self, and focusing on spiritual aspects of self. Self-reported MS symptoms were less severe following use of alternative therapies (p < .0005). Study of the differential effects of single and combined alternative therapies on functional status and symptom severity for large samples of people with MS is recommended.

Use of alternative health therapies by people with multiple sclerosis: an exploratory study.

Sixteen people with multiple sclerosis (MS) responded to a semi-structured questionnaire about their experiences with alternative therapies. No definition of alternative therapies was provided. Physical therapy, counseling, nutrition, and massage were the most frequently used alternative therapies. Other therapies included acupuncture, occupational therapy, aquatic therapy, Therapeutic Touch, yoga, passive exercise, and removal of mercury alloy tooth fillings. Almost two thirds of the respondents reported seeking an alternative health practitioner because traditional physicians offered no cure for MS. Just under one third of the respondents stated that the quality of their lives was improved by alternative therapies.

Nursing informatics as a needed emphasis in graduate nursing administration education: the student perspective.

The faculty of Northeastern University College of Nursing in Boston, MA have initiated a nursing informatics emphasis within the graduate nursing administration specialization. This article describes the increasing need for an aggregate of information systems educational opportunities for the nursing managers of the future, followed by a detailed appraisal of the new informatics courses offered in the nursing administration curriculum from the perspective of this learner. In addition, the author also describes the merits of pursuing a Directed Study practicum, which focused on learning the role accountabilities of a hospital-based nursing information systems manager.

Characteristics of pediatric intermediate care units in pediatric training programs.

BACKGROUND/OBJECTIVE: To assess effective alternate care sites for the technology-dependent, but less acute critically ill child, we surveyed pediatric training programs to determine the availability and characteristics of non-neonatal pediatric intermediate care units. METHODS: A questionnaire was mailed to the program directors of all 226 United States pediatric residency programs in October 1988. Institutions were queried about pediatric residency program and hospital demographics, along with specific day-to-day management issues in an intermediate care unit. RESULTS: The intermediate care unit offers highly skilled nursing care with greater than 90% of the units primarily covered by RNs in a 1:2 or 1:3 RN/patient ratio. The technologies used in these units were similar to those technologies used in an ICU, and the average daily bed charge was 40% less than the average daily bed charge in an ICU. However, an intermediate care unit was present in only 33% of pediatric training programs and pediatric residents were not specifically trained to care for patients in these units; 37% of these units did not have daily attending physician/nurse/resident rounds, despite the complexity and degree of illness in the patients located in these units. In addition, greater than 20% of intermediate care units were predominantly staffed by RNs with degrees less than BSN. Thirteen percent of these units had a predominance of RNs with only routine experience. CONCLUSIONS: Standard levels of care and academic and financial guidelines should be established to optimize the value of pediatric intermediate care units.

Adenosine deaminase in stroma-free hemoglobin solution is not responsible for coronary vasoconstriction.

Erythrocytes contain a high concentration of cytosolic adenosine deaminase and this enzyme activity is present in preparations of stroma-free hemoglobin (SFHS). The documented vasoconstrictor activity of SFHS preparations does not appear to be due to interference with endogenous adenosine-mediated mechanisms, because removal of greater than 80% of adenosine deaminase activity failed to affect the vasoconstrictor potency of SFHS preparations. We have also demonstrated the presence of a contractility-depressant activity in SFHS when the latter was added to aqueous buffer perfusing rat Langendorff-hearts. This activity is diminished in phosphocellulose-purified preparations with reduced adenosine deaminase activity but is not necessarily causally related to this enzyme.

Vitellogenin gene expression in male rainbow trout (Salmo gairdneri).

Estrogen has a marked effect on the expression of vitellogenin, the egg yolk precursor protein in the liver of egg-laying vertebrates. cDNA clones specific for trout vitellogenin mRNA have been used to study the expression of the vitellogenin genes in rainbow trout (Salmo gairdneri). The steady-state levels of vitellogenin mRNA in the liver of male rainbow trout were measured during primary and secondary stimulation with estradiol. The kinetics of induction in trout appear to be very similar to those seen in Xenopus and chicken in that a lag of approximately 2 days is observed in the accumulation of serum vitellogenin during primary induction. This lag is not observed during the secondary stimulation. The primary induction of vitellogenin mRNA in trout liver, using a single injection of estradiol (3 mg/kg body wt) results in a short-lived rise, reaching a maximum level of 260 ppm total RNA on Day 2. Using silastic implants of estradiol to induce a primary response produces a large increase in the steady-state level of vitellogenin mRNA which reaches a maximum of 2750 ppm total RNA on Day 10. During secondary stimulation, using silastic tubing the maximum level reached was 1200 ppm of the total RNA on Day 7, approximately half the level seen in the primary induction using the silastic implants. The difference in these two levels is due to an increase in the steady-state levels of rRNA, which appear to increase between Days 10 and 21 after the primary stimulation. These results demonstrate that the induction of vitellogenesis in the trout by estradiol involves changes in the steady-state levels of a number of different mRNA and rRNA sequences and resembles that seen in Xenopus and chicken.

Is leucine an allosteric modulator of the lysine transporter in the intestinal basolateral membrane?

The transport of the dibasic amino acid L-lysine was investigated using basolateral membrane vesicles prepared from rat jejunal mucosal scrapings. The majority of the carrier-mediated transport was unaffected by the presence of sodium in the incubation medium, but voltage clamping of the vesicles did increase lysine uptake, indicating an associated movement of charge. Kinetic analysis of lysine influx and efflux showed the system to be symmetrical, but although the Vmax was comparable to other amino acid transport systems in this membrane, the dissociation constant for the overall reaction (KT) was an order of magnitude larger. This low affinity for lysine would explain the relatively slow rate of transport of this amino acid across the basolateral membrane. Competition experiments indicated that this system has a relatively narrow specificity carrying only lysine, arginine, ornithine, and histidine. In contrast the presence of L-leucine caused a marked stimulation of lysine efflux and influx across the vesicles. This effect was observed with leucine concentrations as low as 0.1 microM. It is concluded that although the lysine transport system in the basolateral membrane is slow in its basal state it can be rapidly turned on by the presence of L-leucine. The remarkably low concentrations required to do this suggest a possible allosteric interaction between the transporter and this neutral amino acid.

Androgen-repressed messages in the rat ventral prostate.

Poly (A)+ RNA from the prostates of both intact and castrated rats was translated in a message-dependent reticulocyte lysate, and the translation products were electrophoresed on SDS/polyacrylamide gels. Fluorography of these gels showed the expected disappearance, after castration, of the prostate steroid-binding proteins as well as a number of other androgen-dependent proteins. Two major (Mr 40,000 and 45,000) and several minor proteins appeared in the translation products of the castrated rat prostate RNA. Criss-cross liquid hybridization analysis between prostate poly (A+) RNA from intact and castrated rats also showed the disappearance of the abundant prostate steroid-binding protein sequences after castration and the synthesis of several new low to medium abundance sequences. Northern hybridization experiments demonstrated the presence of at least two, and possibly four androgen-repressed poly (A)+ RNA sequences. The most prominent of these, an RNA of 2,000 nucleotides, appeared within 2 days of castration, reaching a maximum on day 4 at a level approximately 400 times greater than the normal level. The other major sequence (a sequence of 1,000 nucleotides) appears after 4 days, reaching a peak between days 8 and 11. Sequences similar to these new RNAs could play an important role in the long-term resistance of prostatic cancer to hormone therapy in humans.

Auditory processing abilities in children with previous middle ear effusion.

The present study was designed to determine whether auditory processing disorders are present in children with documented middle ear effusion (MEE) that required surgical treatment. Children with previous MEE and control subjects, in two age groups, were studied using five tests of auditory processing abilities: low-pass filtered speech, staggered spondaic word test, speech in noise, auditory sequential memory, and sound blending. Results found differences in groups at mean age 7 on the filtered speech tests, but no statistical differences were found on any other test at age 7 or on any test at mean age 9. The results indicate that well-managed MEE appears to have no long-term effects on children acquiring this disease.

TEM study of the central dark line in enamel crystallites.

The dark line which is observed in enamel crystallites represents a planar defect involving a single 100 plane of the hydroxyapatite structure. It may occur in the majority of crystals throughout the enamel, although it is only observed in specific diffraction conditions. Its presence may be related both to the formation and growth of crystallites in the developing tooth and to the manner in which the crystallites dissolve during caries. TEM studies show clearly that the central defect is not a dislocation, stacking fault or lattice twin boundary. They further indicate that it cannot represent a structural twin boundary. The remaining possibilities are that it represents a substitution in the HAP lattice, most likely involving carbonate ion, or a separate compatible calcium phosphate phase.

Identification of Au-Sn phase in Ag3Sn alloys containing gold.

Substitution of gold in part for silver in Ag3Sn alloys is found to result in two separate phases: gamma (Ag3Sn particles) grains with a uniform distribution of gold within the grain and an Au-Sn phase in a form of ring surrounding the gamma grain. The thickness of this ring increases with increasing gold concentration. The phases were identified by using the techniques of x-ray diffraction, optical metallography, scanning electron microscopy, and x-ray energy dispersive spectroscopy.