Gcn5 and Rpd3 have a limited role in the regulation of cell cycle transcripts during the G1 and S phases in Saccharomyces cerevisiae.

Activation of cell cycle regulated transcription during the G1-to-S transition initiates S phase entry and cell cycle commitment. The molecular mechanisms involving G1/S transcriptional regulation are well established and have been shown to be evolutionary conserved from yeast to humans. Previous work has suggested that changes to the chromatin state, specifically through histone acetylation, has an important role in the regulation of G1/S transcription in both yeast and human cells. Here we investigate the role of histone acetylation in G1/S transcriptional regulation in the budding yeast Saccharomyces cerevisiae. Our work shows that histone acetylation at specific sites at G1/S target gene promoters peaks at the G1-to-S transition, coinciding with their peak transcription levels. Acetylation at G1/S target promoters is significantly reduced upon deletion of the previously implicated histone acetyltransferase Gcn5, but G1/S cell cycle regulated transcription is largely unaffected. The histone deacetylase Rpd3, suggested to have a role in Whi5-dependent repression, is required for full repression of G1/S target genes in the G1 and S phases. However, in the context of transcriptionally active levels during the G1-to-S transition, this seems to play a minor role in the regulation of cell cycle transcription. Our data suggests that histone acetylation might modulate the amplitude of G1/S cell cycle regulated transcription in Saccharomyces cerevisiae, but has a limited role in its overall regulation.

Nephrostomies in obstructive uropathy; how should hormone resistant prostate cancer patients be managed and can we predict who will benefit?

Current opinion advocates the use of nephrostomies in hormone naive patients with obstructive uropathy while hormone resistant patients require an individual approach. Patients undergoing a nephrostomy for uropathy were retrospectively analysed, with particular interest in hormone status and blood levels. Over a 46-month period, 26/112 nephrostomies were performed for prostate cancer induced uropathy. Survival was 226.5 days for hormone naive patients, 114.3 days in the responsive group and 100.2 days if resistant. Bilateral cases survived 72.1 days versus 157.6 days for unilateral patients. All patients should be considered for nephrostomy despite their hormone status.

On the occurrence of polymers of H1, H1(0) and H5 in extracts of whole tissues. Artificial production during protein preparation.

Inspection of preparations of H1, H1(0) and H5 histones made by extraction of whole tissues has shown that dimers and higher polymers of all three of these proteins are present. They may be formed by the cross-linking action of poly(ADP-ribose) chains which are linked to some of the protein molecules. Putative dimers and higher polymers were noted in preparations from various tissues and species. However, evidence is presented which suggests that production of these polymers is an artifact of precipitation during the preparation of the proteins, so the significance of the polymers is questionable.

Temperature and viscosity dependence of the electron-transfer reaction between plastocyanin and cytochrome c labeled with a ruthenium(II) bipyridine complex.

The temperature and viscosity dependence of the photo-induced electron-transfer reaction between plastocyanin and cytochrome c labeled at Lys13 with Ru(4,4'-dicarboxybipyridine)(bipyridine)(2+)2 have been investigated. In these studies, a short pulse of 450 nm light was used to excite the ruthenium complex which was oxidatively quenched by the iron center of cytochrome c. The resulting Fe(II) cytochrome c was then rapidly reoxidized by plastocyanin. The reactions were investigated over a temperature range of 3.5 to 37 degrees C under low ionic strength conditions such that protein/protein complex formation was favored. The enthalpy of activation was 7 kcal mol-1 and the entropy of activation was -20 cal mol-1 K-1. Increasing the viscosity by the addition of sucrose up to 70% resulted in a 4-fold decrease in the rate constant for electron transfer. The overall results suggest a rate-limiting step that involves either dissociation of the dominant protein/protein complex or surface diffusion of the associated proteins.

Maintenance of eupnea and gasping following alterations in potassium ion concentration of perfusates of in situ rat preparation.

Levels of extracellular potassium ion, above those in vivo, are required for the generation of rhythmic activities of in vitro preparations. Our purpose was to define whether hyperkalemia in the perfusate of an in situ preparation was likewise necessary for the expression of eupnea and gasping. Studies were performed using the in situ preparation of the juvenile rat, in which activity of the phrenic nerve was recorded as an index of the respiratory rhythm. Eupnea and gasping were impervious to modifications of potassium ion of the perfusate. Eupnea was maintained uninterrupted for more than 60 min whether the total concentration of potassium was hypokalemic (2.75 mM), normokalemic (4.0 mM), or hyperkalemic (6.25 and 7.75 mM). Gasping, with identical characteristics, was elicited at any concentration of potassium ion. We conclude that both eupnea and gasping are unaffected by modest changes in the concentration of potassium ion in the perfusate with which the in situ rat preparation is maintained. These results add further support to the conclusion that the in situ preparation represents a model that accurately reproduces mechanisms of rhythm generation of both eupnea and gasping in vivo.

Racial differences in the distribution of a low density lipoprotein receptor-related protein (LRP) polymorphism and its association with serum lipoprotein, lipid and apolipoprotein levels.

The low density lipoprotein (LDL) receptor-related protein (LRP) is a cell receptor that has close structural homology to the LDL and very low density lipoprotein receptors and thus is believed to play an important role in lipid metabolism. This study was carried out to evaluate the distribution of a known tetranucleotide repeat polymorphism in the LRP gene and its association with serum lipoprotein-lipid and apolipoprotein levels in four large samples comprising Hispanics (n=373) and non-Hispanic Whites (n=522) from the U.S. and Nigerian Blacks from Sokoto (n=390) and Benin (n=800). A total of four alleles, designated 83, 87, 91 and 95 bp, were observed. The 83 bp allele was observed at 0.4-1.1% in the two U.S. populations but was completely absent in African Blacks. Sokoto Blacks had significantly different frequencies of the 87 and 91 bp alleles compared to Hispanics (P=0.008) and non-Hispanic Whites (P=0.024). The frequency of the 91 bp allele was also significantly higher in Benin Blacks compared to Hispanics (P=0.026) and non-Hispanic Whites (P=0.054). The analysis of the relationship between the LRP polymorphism and serum lipid traits yielded some significant race and gender specific significant association for lipoprotein(a) in non-Hispanic White males (P=0.02); HDL2-cholesterol in Hispanic females (P=0.03) and apolipoprotein B in Benin males (P=0.04). We also observed an interaction between the LRP polymorphism and menopausal status for Lp(a) in Hispanic females (P=0.014). However, considering multiple comparisons were performed, these associations could be due to chance. Our data indicate that although the LRP tetranucleotide polymorphism exhibits inter-racial differences in its distribution, it does not appear to have a significant role in affecting serum lipid traits.

Boron neutron capture enhancement of 252Cf brachytherapy.

Dosimetric and radiobiological studies were undertaken to investigate the potential enhancement in dose, dose distribution and cell killing effectiveness of 252Cf brachytherapy achievable when boron-10 enriched compounds are incorporated into simulated 252Cf brain implants. Thermal neutron distributions in a human head phantom containing a 252Cf source were measured by gold foil activation and calculated using a 1-dimensional transport code. This information was then used to modify measured event size distributions for 252Cf neutrons to determine the corresponding increase in dose and dose equivalent throughout the phantom. The addition of subtoxic levels of boron-10 to a typical 252Cf implant was found to significantly enhance both the absorbed dose and the high LET event frequency at distances of 3 to 5 cm from individual sources. Some unexpected geometric considerations are discussed. Reduced survival of cultured Chinese hamster cells correlated with the predicted increase in absorbed dose from the capture events with a concentration of about 60 micrograms 10B per ml in the culture medium. It was found that boron increased alpha (the "single-hit" parameter of the linear quadratic survival model) by 32% and decreased beta (the "double-hit" parameter) by 8%. The alpha/beta ratio increased to 4.34 Gy in the presence of boron, from 3.03 Gy in its absence. This translated to an 8% reduction in californium dose needed to effect 10% cell survival. It is concluded that there is a sufficiently high thermal neutron fluence present during californium brachytherapy for boron neutron capture dose augmentation to be feasible.

Non-radioactive techniques for the labelling of nucleic acids.

Non-radioactively labelled probes potentially have several advantages over radioactively labelled ones, such as increased stability and reduced hazard. As yet, no non-radioactive methods of labelling are as robust or produce as sensitive a probe as 32P. However, there are many options, some of which use approaches familiar to 32P users (nick translation, random priming, tailing). The majority of methods, whether enzymatic or chemical, direct or indirect, ultimately require the detection of an enzyme by a colourimetric or chemiluminescent substrate. Such detection can be achieved variously by direct visualisation (e.g. of a colourimetrically stained blot), by film, by microtitre plate reader or by CCD camera, depending on the choice of assay format and the degree of quantification required.

Evidence for heterogeneity of the DPA and DPB alleles derived from a DRw11,DQw7,DPw4 cell line.

We have previously reported the complete sequence of the cDNAs corresponding to the alleles at the polymorphic loci (DRB1, DRB3, DQA1, DQB1) of the DRw11(5) cell line Swei. We now report the nucleotide and derived amino acid sequence of the alleles at the remaining two polymorphic loci, DPA1 and DPB1, from Swei, which types as DPw4b. Comparison of the DPw4b alpha sequence with previous DP alpha sequences indicates that it is identical to the DP alpha chains of DPw4 and DPw2. However, the DPw4b alpha cDNA encodes a unique 3' untranslated region that corresponds to sequences contained within the last intron of the DP alpha genomic gene. These results indicate that alternative splicing occurs within the Swei DP alpha RNA. Comparison of the DPw4b beta sequence with previously reported DP beta sequences indicates that the first domain is identical to the sequence of the DP beta chain derived from the Burkhardt (Burk) cell line, but that the second domain differs by two amino acids. In addition, a single amino acid difference from DPw2 at position 69 in the first domain of the DPw4b beta chain suggests that this residue is important in determining DP specificity. Furthermore, comparison with other DP beta DNA sequences suggests that variable regions occur at positions 8-11, 55-57, and 84-87.

Embedded structures and representation of nursing knowledge.

Nursing Vocabulary Summit participants were challenged to consider whether reference terminology and information models might be a way to move toward better capture of data in electronic medical records. A requirement of such reference models is fidelity to representations of domain knowledge. This article discusses embedded structures in three different approaches to organizing domain knowledge: scientific reasoning, expertise, and standardized nursing languages. The concept of pressure ulcer is presented as an example of the various ways lexical elements used in relation to a specific concept are organized across systems. Different approaches to structuring information-the clinical information system, minimum data sets, and standardized messaging formats-are similarly discussed. Recommendations include identification of the polyhierarchies and categorical structures required within a reference terminology, systematic evaluations of the extent to which structured information accurately and completely represents domain knowledge, and modifications or extensions to existing multidisciplinary efforts.

The maturation of the somatostatin systems in the rat visual cortex.

The development of somatostatin-immunoreactive (SS) neurons and processes in the rat visual cortex (VC) was studied in animals from embryonic day 20 (E20) to postnatal day 21 (D21). Three distinct patterns of immunoreactivity were seen. From E20 to birth (D0), VC was characterized by a small number of mainly bipolar SS neurons throughout the cortical plate. In the perinatal period, from D1 to D6, there were large numbers of immature immunoreactive neurons which were confined to layer VI and the subplate zone, a few bipolar neurons in the cortical plate and an extremely dense plexus of SS processes throughout the neuropil. The third phase, from D8 to weaning, was characterized by the absence of immature SS neurons, an increase in the number of multipolar SS neurons and a decrease in the density of SS fibers. By D15, the time of eye-opening, the number and distribution of SS neurons and processes was close to that seen in the adult. These results indicate that the SS system of neurons and fibers is among the earliest of the transmitter systems to be established in VC and suggests a role for the peptide in cortical organization as well as visual processing.

The right to refuse psychiatric treatment in Kentucky.

During the last 30 years, involuntarily committed psychiatric patients have utilized the justice and legislative systems to delineate their legal rights to refuse treatments prescribed by their psychiatrists. In this paper, the legal and medical implications of the right to refuse psychiatric treatment in the Commonwealth of Kentucky are reviewed. A brief history of the legal precedents is presented, followed by a review of studies on the impact of these developments on patient care. The specific laws and regulations of Kentucky in this area are then reviewed. Approaches to the treatment-refusing patient are then discussed, with emphasis on using a cooperative approach with refusing patients and maintaining a positive doctor-patient relationship. The process of obtaining court-ordered treatment on patients is then reviewed, with emphasis on the legal and clinical implications of this decision and suggestions for psychiatrists who feel that this approach is warranted.

Completed suicides and emergency psychiatric evaluations: the Louisville experience.

Suicide is one of the most serious outcomes of psychiatric illness, and the most extreme intervention (involuntary hospitalization) can be exercised if this event is likely. Despite this, the rate of suicide has remained fairly consistent at 1.1-1.4%. In an ongoing effort of identifying factors that can predict subsequent suicides, we retrospectively examined the records of individuals who completed suicides in Jefferson County, January 1997 through September 1998, and who were evaluated at the Emergency Psychiatric Service (EPS) at University of Louisville Hospital. Fifteen of the 132 (11.4%) subjects who completed suicide were evaluated at some point in time at EPS. Only 8 (6.1%) were seen within 60 days of the fatal event. This represents less than 0.1% of the total 9,469 patients seen at the EPS during this time period. No specific factors could be identified that predicted imminent suicide. Given the inaccuracy in being able to predict suicide, clinicians need to continue to be vigilant when assessing acutely distressed substance abusing or psychiatric patients.

Patient outcomes: assessment issues for the CNS.

Patient outcomes are becoming markers of health care effectiveness and quality. The CNS is uniquely positioned to influence outcomes evaluation within nursing. One way to accomplish this is through recommendations on the selection and use of appropriate patient assessment tools within the patient database. Recommendations of the CNS should be based on: an awareness of patient outcomes of particular interest to nursing; a goal of standardized, retrievable clinical data; characteristics of clinically appropriate assessment tools for outcomes evaluation; and data needs of patient outcomes research as well as traditional clinical research.

Factors influencing functional outcome and discharge disposition after thoracic spinal cord injury.

The purpose of this retrospective study was to describe the relationships among level of injury, completeness of impairment, age, complexity of coexistent disease, functional outcomes, and discharge disposition in persons with traumatic thoracic spinal cord injury (SCI). The sample consisted of 41 persons with acute traumatic thoracic SCI discharged from a 48-bed rehabilitation unit between 1992 and 1997. Persons with complete SCI had significantly lower Functional Independence Measure scores than persons with incomplete SCI (p < .05). The effect of the completeness of injury did not persist to discharge FIM scores. Persons discharged to home without a home-health referral (HHR) had higher FIM scores than those discharged to home with one. Persons discharged to home with an HHR had higher FIM scores than those discharged to skilled nursing facility units, although these were not statistically significant. The findings of this study suggest that rehabilitation goals and discharge disposition planning for persons with traumatic thoracic SCI cannot be based on level and completeness of injury alone. The interdisciplinary team must understand the abilities, needs, and disposition of this population to develop rehabilitation goals and interventions that are feasible and realistic.