Top Ten Tips Palliative Clinicians Should Know About Rural Palliative Care in the United States

Palliative care improves outcomes, yet rural residents often lack adequate and equitable access. This study provides practical tips to address palliative care (PC)-related challenges in rural communities. Strategies include engaging trusted community partners, addressing cultural factors, improving pediatric care, utilizing telehealth, networking with rural teams including caregivers, and expanding roles for nurses and advanced practice providers. Despite complex barriers to access, providers can tailor PC to be patient-centered, respect local values, and bridge gaps. The "Top 10" format emphasizes the relevant issues to enable clinicians to provide optimal care for people from rural areas.

The associations among nurse work engagement, job satisfaction, quality of care, and intent to leave: A national survey in the United States

Objectives

Employee work engagement, job satisfaction, quality of care, and intent to leave are critical indicators for healthcare organizational performance. This study aimed to analyze the current state of nurses' work engagement and its factors to examine the associations among nurses' work engagement, job satisfaction, quality of care, and intent to leave in the United States (US).

Methods

This is a quantitative descriptive cross-section design. Data were collected online from the US registered nurses from March to September 2022. Measures comprised the Utrecht Work Engagement Scale, the demographics, and questions regarding job satisfaction, perceived quality of care, and intent to leave.

Results

Nine hundred nurses participated in the online survey. Among the participants, 79.2% reported holding a specialty certification, 59.4% scored high/very high on job satisfaction, 82.2% expressed high/very high on the perceived quality of nursing care, and 28.4% conveyed likely/very likely to leave in the following year. Nurses' work engagement was positively associated with nurses' job satisfaction and their perceived quality of care but negatively associated with intent to leave. More certified nurses reported high or very high job satisfaction than non-certified nurses. As for demographics, the linear regression analysis showed that nurses who were older, identified as White, and held doctorate degrees reported higher levels of work engagement in comparison to their counterparts.

Conclusions

This study shows that nurses' work engagement is associated with their job satisfaction, perceived quality of care, and intent to leave. Nurses' work engagement in this study is lower than in other studies, especially before the COVID-19 pandemic, which may indicate a possible association with the COVID-19 impact. Because nurses' work engagement is significantly associated with job satisfaction, nurse leaders need to find ways to promote nurses' job satisfaction and retention.

Augmentation of Pedicle Screws Using Bone Grafting in Patients with Spinal Osteoporosis

The aim of the study was to develop a new method of vertebral augmentation based on autologous and allogeneic bone chips to be used in pedicle screw fixation and to compare this method with the technique based on polymethyl methacrylate (PMMA).

Poly(glycoamidoamine) brush nanomaterials for systemic siRNA delivery in vivo

Delivery is the key challenge for siRNA based therapeutics. Here, we report the development of new poly(glycoamidoamine) brush nanomaterials for efficient siRNA delivery. GluN4C10 polymer brush nanoparticles, a lead material, demonstrated significantly improved delivery efficiency for siRNA against factor VII (FVII) in mice compared to poly(glycoamidoamine) brush nanomaterials reported previously.

Intraosseous basivertebral nerve ablation for the treatment of chronic low back pain: a prospective randomized double-blind sham-controlled multi-center study

PURPOSE

To evaluate the safety and efficacy of radiofrequency (RF) ablation of the basivertebral nerve (BVN) for the treatment of chronic low back pain (CLBP) in a Food and Drug Administration approved Investigational Device Exemption trial. The BVN has been shown to innervate endplate nociceptors which are thought to be a source of CLBP.

METHODS

A total of 225 patients diagnosed with CLBP were randomized to either a sham (78 patients) or treatment (147 patients) intervention. The mean age within the study was 47 years (range 25-69) and the mean baseline ODI was 42. All patients had Type I or Type II Modic changes of the treated vertebral bodies. Patients were evaluated preoperatively, and at 2 weeks, 6 weeks and 3, 6 and 12 months postoperatively. The primary endpoint was the comparative change in ODI from baseline to 3 months.

RESULTS

At 3 months, the average ODI in the treatment arm decreased 20.5 points, as compared to a 15.2 point decrease in the sham arm (p = 0.019, per-protocol population). A responder analysis based on ODI decrease ≥ 10 points showed that 75.6% of patients in the treatment arm as compared to 55.3% in the sham control arm exhibited a clinically meaningful improvement at 3 months.

CONCLUSION

Patients treated with RF ablation of the BVN for CLBP exhibited significantly greater improvement in ODI at 3 months and a higher responder rate than sham treated controls. BVN ablation represents a potential minimally invasive treatment for the relief of chronic low back pain. These slides can be retrieved under Electronic Supplementary Material.

South African guideline on deep brain stimulation for Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is a common neurodegenerative disease, associated with severe impairment of quality of life. Although the motor aspects of the illness are typically successfully treated with medications acting on the dopaminergic system, a number of patients encounter progressive difficulties associated with their medical treatment.

RECOMMENDATIONS

Carefully selected patients will benefit from deep brain stimulation (DBS) treatment for their PD. Selection requires dopamine challenge testing and neuropsychological testing for the presence of cognitive impairment. Careful follow-up and programming of the DBS system are mandatory, and a major reason for DBS failure is inadequate programming and management of medication.

CONCLUSION

DBS is a useful component of standard therapy for PD and may reduce symptoms, improve quality of life, promote patient independence and reduce healthcare costs by reducing requirements for medicine.

Therapeutic efficacy in a hemophilia B model using a biosynthetic mRNA liver depot system

DNA-based gene therapy has considerable therapeutic potential, but the challenges associated with delivery continue to limit progress. Messenger RNA (mRNA) has the potential to provide for transient production of therapeutic proteins, without the need for nuclear delivery and without the risk of insertional mutagenesis. Here we describe the sustained delivery of therapeutic proteins in vivo in both rodents and non-human primates via nanoparticle-formulated mRNA. Nanoparticles formulated with lipids and lipid-like materials were developed for delivery of two separate mRNA transcripts encoding either human erythropoietin (hEPO) or factor IX (hFIX) protein. Dose-dependent protein production was observed for each mRNA construct. Upon delivery of hEPO mRNA in mice, serum EPO protein levels reached several orders of magnitude (>125 000-fold) over normal physiological values. Further, an increase in hematocrit (Hct) was established, demonstrating that the exogenous mRNA-derived protein maintained normal activity. The capacity of producing EPO in non-human primates via delivery of formulated mRNA was also demonstrated as elevated EPO protein levels were observed over a 72-h time course. Exemplifying the possible broad utility of mRNA drugs, therapeutically relevant amounts of human FIX (hFIX) protein were achieved upon a single intravenous dose of hFIX mRNA-loaded lipid nanoparticles in mice. In addition, therapeutic value was established within a hemophilia B (FIX knockout (KO)) mouse model by demonstrating a marked reduction in Hct loss following injury (incision) to FIX KO mice.

Creating Effective Media Messaging for Rural Smoke-free Policy

OBJECTIVES

Objectives were to (1) explore perceived effectiveness of existing smoke-free print advertisements in rural communities and (2) generate message content, characteristics, and media delivery channels that resonate with residents.

DESIGN AND SAMPLE

Qualitative methods design. Thirty-nine rural adults recruited by community partners.

MEASURES

Content analysis of findings from individuals in four focus groups who participated in general discussion and reviewed eight print ads related to secondhand smoke (SHS) and smoke-free policy.

RESULTS

Six content themes were identified: smoking/SHS dangers, worker health, analogies, economic impact, rights, and nostalgia. Seven message characteristics were recognized: short/to the point, large enough to read, graphic images, poignant stories, statistics/charts/graphs, message sender, and messages targeting different groups. Four media delivery channels were considered most effective: local media, technology, billboard messages, and print materials.

CONCLUSIONS

Seeking input from key informants is essential to reaching rural residents. Use of analogies in media messaging is a distinct contribution to the literature on effective smoke-free campaigns. Other findings support previous studies of effective messaging and delivery channels. Further research is needed to examine effectiveness of themes related to message content in smoke-free ads and delivery strategies. Effective media messaging can lead to policy change in rural communities to reduce exposure to SHS.

Two missense mutations in melanocortin 1 receptor (MC1R) are strongly associated with dark ventral coat color in reindeer (Rangifer tarandus)

The protein-coding region of melanocortin 1 receptor (MC1R) was sequenced to identify potential variation affecting coat color in reindeer (Rangifer tarandus). A T→C sequence variation at nucleotide position 218 (c.218T>C) causing an amino acid (aa) change from methionine to threonine at aa position 73 (p.Met73Thr) was identified. In addition, a T→G sequence variation was found at nucleotide position 839 (c.839T>G), causing phenylalanine to be exchanged by cysteine at aa position 280 (p.Phe280Cys). The two sequence variants (c.218C and c.839G) were found to be closely associated with a darker belly coat compared with animals not having any of these two variants. The aa acid change p.Met73Thr affects the same position as p.Met73Lys previously reported to give constitutive activation of MC1R in black sheep (Ovis aries), whereas p.Phe280Cys is identical to one of two variants previously reported to be associated with dark coat color in Arctic fox (Alopex lagopus), supporting that the two variants found in reindeer are functional. The complete absence of Thr73 and Cys280 among the 51 wild reindeer analyzed provides some evidence that these variants are more common in the domestic herds.

Chemically diverse polymer microarrays and high throughput surface characterisation: a method for discovery of materials for stem cell culture†Electronic supplementary information (ESI) available. See DOI: 10.1039/c4bm00054dClick here for additional data file

Chemically diverse polymer microarrays as a powerful screening tool for the discovery of new materials for a variety of applications.

Materials discovery provides the opportunity to identify novel materials that are tailored to complex biological environments by using combinatorial mixing of monomers to form large libraries of polymers as micro arrays. The materials discovery approach is predicated on the use of the largest chemical diversity possible, yet previous studies into human pluripotent stem cell (hPSC) response to polymer microarrays have been limited to 20 or so different monomer identities in each study. Here we show that it is possible to print and assess cell adhesion of 141 different monomers in a microarray format. This provides access to the largest chemical space to date, allowing us to meet the regenerative medicine challenge to provide scalable synthetic culture ware. This study identifies new materials suitable for hPSC expansion that could not have been predicted from previous knowledge of cell-material interactions.

Minimally invasive surgery for the lumbar spine

Minimally invasive spine surgery is a rapidly developing field that has the potential to decrease surgical morbidity and improve recovery compared to traditional spinal approaches. Minimally invasive approaches have been developed for all regions of the spine, but have been best documented for degenerative conditions of the lumbar spine. Lumbar decompression and lumbar interbody fusion are two of the most well-studied minimally invasive surgical approaches. This article will review both the rationale and technique for minimally invasive lumbar decompression and for a minimally invasive transforaminal lumbar interbody fusion (TLIF).

In Vivo Cloning of lac Genes in Streptococcus lactis ML3

The isolation and characterization of a Streptococcus lactis ML3 strain which possessed a recombinant lactose plasmid is described. The recombination events generating this plasmid occurred in vivo in a recombination-deficient strain and appeared to be mediated by transposition events. Restriction mapping revealed that the recombinant plasmid, pDA0307, contained a region of the lactose plasmid, pSK08, linked to another resident plasmid, pSK07. Copy number determinations indicated that the lac genes were present at approximately 20 copies per cell in pDA0307, whereas the lac genes are normally present at approximately 10 copies per cell in pSK08. The strain containing pDA0307 displayed a 21 to 54% increase in the expression of the Lac enzyme phospho-beta-d-galactosidase. However, the strain containing pDA0307 both grew and produced lactic acid in milk at rates identical to that of a strain containing pSK08. This result suggests that lac gene dosage of plasmid-linked lac genes was not limiting the rate at which these derivatives of S. lactis ML3 fermented milk.

Lipid-based nanotherapeutics for siRNA delivery

RNA interference (RNAi) is a specific gene-silencing mechanism triggered by small interfering RNA (siRNA). The application of RNAi in the clinic requires the development of safe and effective delivery systems. Inspired by progress with lipid-based systems in drug delivery, efforts have been dedicated to the development of liposomal siRNA delivery systems. Many of the lipid-based delivery vehicles self-assemble with siRNA through electrostatic interactions with charged amines, generating multi-lamellar lipoplexes with positively charged lipid bilayers separated from one another by sheets of negatively charged siRNA strands. Internalization of lipid-based siRNA delivery systems into cells typically occurs through endocytosis; accordingly, delivery requires materials that can facilitate endosomal escape. The size of the carrier is important as carriers <100 nm in diameter have been reported to have higher accumulation levels in tumours, hepatocytes and inflamed tissue, whereas larger particles tend to be taken up by Kupffer cells or other components of the reticuloendothelial system (RES). To reduce RES uptake and increase circulation time, carriers have been modified on the surface with hydrophilic materials, such as polyethyleneglycol. Herein, we review the molecular and structural parameters of lipid-based siRNA delivery systems.

Inhibition of the oxidative metabolism of 3,4-dihydroxyphenylacetaldehyde, a reactive intermediate of dopamine metabolism, by 4-hydroxy-2-nonenal

Recent evidence indicates a role for oxidative stress and resulting products, e.g. 4-hydroxy-2-nonenal (4HNE) in the pathogenesis of Parkinson's disease (PD). 4HNE is a known inhibitor of mitochondrial aldehyde dehydrogenase (ALDH2), an enzyme very important to the dopamine (DA) metabolic pathway. DA undergoes monoamine oxidase-catalyzed oxidative deamination to 3,4-dihydroxyphenylacetaldehyde (DOPAL), which is metabolized primarily to 3,4-dihydroxyphenylacetic acid (DOPAC) via ALDH2. The biotransformation of DOPAL is critical as previous studies have demonstrated this DA-derived aldehyde to be a reactive electrophile and toxic to dopaminergic cells. Therefore, 4HNE produced via oxidative stress may inhibit ALDH2-mediated oxidation of the endogenous neurotoxin DOPAL. To test this hypothesis, ALDH2 in various model systems was treated with 4HNE and activity toward DOPAL measured. Incubation of human recombinant ALDH2 with 4HNE (1.5-30 microM) yielded inhibition of activity toward DOPAL. Furthermore, ALDH2 in rat brain mitochondrial lysate as well as isolated rat brain mitochondria was also sensitive to the lipid peroxidation product at low micromolar, as evident by a decrease in the rate of DOPAL to DOPAC conversion measured using HPLC. Taken together, these data indicate that 4HNE at low micromolar inhibits mitochondrial biotransformation of DOPAL to DOPAC, and generation of the lipid peroxidation product may represent a mechanism yielding aberrant levels of DOPAL, thus linking oxidative stress to the uncontrolled production of an endogenous neurotoxin relevant to PD.

Enhanced undergraduate public health nursing experience: a collaborative experience with the Kentucky Department for Public Health

The Kentucky Department for Public Health and the University of Kentucky College of Nursing entered into a collaborative partnership to provide an enhanced public health nursing experience for a select group of undergraduate students. The purpose of the project was to strengthen the public health nursing practices component of the baccalaureate nursing program in the College of Nursing at the University of Kentucky. The objectives of the project related to planning, implementing, and evaluating of this program in partnership with the Kentucky Cabinet for Health Services, State Health Department in Frankfort, Kentucky. The selected baccalaureate students were paired with a preceptor and a state, local, or district public health agency with an identified need in the student's area of interest. The students participated in a mentoring experience with a practicing public health nurse consultant. The experience afforded the students an opportunity to interact at both the practice and policy development levels. An ongoing partnership developed between the state health department, local health departments, and the college of nursing. This partnership led to ongoing practicum placements for students, beneficial for both the health departments and the college of nursing.

Workplace violence in long haul trucking: occupational health nursing update

Almost 2 million workdays and millions of dollars are lost annually because of non-fatal assaults suffered at the workplace (NIOSH, 1996). Twenty workers, on average, are murdered each week in the United States and an estimated 18,000 workers per week are victims of non-fatal assault (NIOSH, 2001). Violence and stress are two interrelated issues that affect the work force. In-depth studies of these issues have not been conducted with long haul truckers in general, or with women in non-traditional, male dominated fields such as the long haul trucking industry. Epidemiological data related to violence and stress experienced by these under-studied populations are needed to plan effective interventions to reduce occupational risks. Studies employing both qualitative and quantitative methods are needed to articulate risk and protective factors related to violence against workers (Runyan, 2001). Occupational health nurses are qualified to participate in the development and implementation of research and intervention studies to improve worker safety related to violence at the workplace for men and women in both traditional and non-traditional occupational roles.

Factors Influencing Homelessness in Women

The specific aims of the article were to: (i) compare childhood experiences of intimacy and autonomy as they occurred in the families of origin of women who have and women who have not experienced homelessness; (ii) compare social support, reciprocity, and conflict as they occurred in the childhood support networks and in the current support networks of women who have and women who have not experienced homelessness; (iii) examine the relationships between intimacy and autonomy in families of origin and the social support networks from childhood of women who have and women who have not experienced homelessness. Descriptive correlational design: 255 women were interviewed to determine levels of intimacy, autonomy, social support, reciprocity, and conflict in childhood relationships. The ANCOVA models for each of support, reciprocity, and conflict indicated a significant group effect. The post-hoc analysis for support indicated that the homeless group was significantly lower in support and reciprocity and significantly higher in conflict than the never-homeless groups. The never-homeless, never-abused group scored significantly higher on autonomy and intimacy than the homeless or the never-homeless, abused groups. This study demonstrates the significance of families of origin and learning how to develop and utilize support systems in preventing or reducing homelessness.

Internet patient care applications in ambulatory care

Over the next decade, the Internet and related technologies will revolutionize the administrative and clinical practices of ambulatory care, enhancing the ability of physicians to provide quality care, enabling "virtual care teams" to help patients deal effectively with acute episodes and chronic conditions, and reducing the cost of care. Like any major paradigm shift, this change will not happen overnight. Nor will it be without cost. The explosion of venture capital and meteoric rise of the Nasdaq in 1999 reflected the promise of the Internet to revolutionize many aspects of American business. The Nasdaq's equally rapid descent in 2000 reflected a growing realization that this change will not be free--that "creative destruction," to use Schumpeter's term, will inevitably require significant investment and produce substantial losses. This article takes a longer term view than the ups and downs in the stock market. We believe the forces unleashed by the Internet are inexorable and that 10 years from now we will look back at the millennium's first decade as a period when the practice of ambulatory medicine was transformed by communication technology.

Noncontact dipole effects on channel permeation. V. Computed potentials for fluorinated gramicidin

Experimental and theoretical calculations indicate that the dipole moment of the four Trp side chains in gramicidin A (gA) channels modify channel conductance through long-range electrostatic interactions. Electrostatic ion/side-chain interaction energies along the channel were computed with CHARMM using ab initio atom charges for native and 4-, 5-, or 6-fluorinated Trp side chains. The bulk water reaction to the polar side chains was included using the method of images as implemented by, and channel waters in idealized structures were included. Ion/Trp interaction energies were approximately -0.6 kcal/mol throughout the channel for all four of the native Trp pairs. Channel waters produced a modest reduction in the magnitude of interactions, essentially offsetting images representing the bulk water outside the channel. The effects of side-chain fluorination depended on ring position and, to a lesser extent, residue number. Compared with native Trp, 5-fluorination reduces the translocation barrier with minor effects on the exit barrier. In contrast, 6-fluorination primarily reduces exit barrier. 4-Fluorination produces a more complex double-well energy profile. Effects of measured side-chain movements resulting from fluorination or change in lipid bilayer were negligible whereas thermal side chain librations cause large effects, especially in the region of the ion-binding sites.

Paleoindian interaction and mating networks: reply to Moore and Moseley

How early human populations in North America maintained reproductive viability is a question that has shaped our research for over a decade. The concept of staging areas, mechanisms for band-macroband interaction, and an examination of how interaction networks could have formed and evolved over the course of the Paleoindian era are all solutions that we have presented.

Families of origin of homeless and never-homeless women

Naturalistic inquiry was used to compare the characteristics of families of origin of homeless women with never-homeless women. The women's experiences in their families of origin were explored during in-depth interviews using Lofland and Lofland's conceptions of meanings, practices, episodes, roles, and relationships to guide the analysis. The two groups were similar with respect to family abuse history, transience, and loss. The never-homeless women had support from an extended family member who provided unconditional love, protection, a sense of connection, and age-appropriate expectations, as contrasted with homeless women who described themselves as being without, disconnected, and having to be little adults in their families of origin. The experience of family love and connection seemed to protect never-homeless women from the effects of traumatic life events in childhood. These findings provide support for the influence of a woman's family of origin as a precursor to homelessness.

Coping strategies and burnout among veteran child protection workers

OBJECTIVES

First, to learn how veteran (2 years or more) child protective service (CPS) investigations workers cope with job stress; and secondly, to examine the relationship between coping strategies and levels of emotional exhaustion, depersonalization, and sense of reduced personal accomplishment (burnout syndrome).

METHOD

Cross-sectional, self-report methodology was used to measure coping strategies and the burnout syndrome. The voluntary subjects were 151 front-line CPS workers with at least 2 years experience in a southeastern Department of Social Services. They attended one of nine stress management workshops provided in various locations around the state. Quantitative analyses were run on the data.

RESULTS

These workers perceived themselves to use Engaged (active) coping strategies more than Disengaged (avoidant) strategies. Sixty-two percent of participants scored in the high range on Emotional Exhaustion, the aspect some researchers consider to be the heart of Burnout. Those who used Engaged coping were less likely to feel depersonalized and more likely to feel a sense of personal accomplishment. Those who used Disengaged coping were more likely to feel emotionally exhausted, depersonalized, and to have a sense of reduced personal accomplishment.

CONCLUSION

Neither the use of active nor avoidant coping strategies saved these workers from Emotional Exhaustion. The problem-focused strategies they are taught and use most do not help deal with the emotional content and context of their work, suggesting the use of emotion-focused coping to prevent and remediate burnout.

A single mutation, RecB(D1080A,) eliminates RecA protein loading but not Chi recognition by RecBCD enzyme

Homologous recombination and double-stranded DNA break repair in Escherichia coli are initiated by the multifunctional RecBCD enzyme. After binding to a double-stranded DNA end, the RecBCD enzyme unwinds and degrades the DNA processively. This processing is regulated by the recombination hot spot, Chi (chi: 5'-GCTGGTGG-3'), which induces a switch in the polarity of DNA degradation and activates RecBCD enzyme to coordinate the loading of the DNA strand exchange protein, RecA, onto the single-stranded DNA products of unwinding. Recently, a single mutation in RecB, Asp-1080 --> Ala, was shown to create an enzyme (RecB(D1080A)CD) that is a processive helicase but not a nuclease. Here we show that the RecB(D1080A)CD enzyme is also unable to coordinate the loading of the RecA protein, regardless of whether chi sites are present in the DNA. However, the RecB(D1080A)CD enzyme does respond to chi sites by inactivating in a chi-dependent manner. These data define a locus of the RecBCD enzyme that is essential not only for nuclease function but also for the coordination of RecA protein loading.

A clinical assessment of the effects of 10% carbamide peroxide gel on human pulp tissue

Bleaching vital teeth with 10% carbamide peroxide gel is a routine procedure in which there has been no evidence of associated permanent pulpal damage. Synthesis of the enzyme heme oxygenase-1 (HO-1) is increased after exposure of eukaryotic cells to conditions of oxidative stress (including H2O2) as a defense against the damaging effects of free radicals. Dental pulps were evaluated for HO-1 (aka Heat Shock Protein 32) presence in teeth treated with 10% carbamide peroxide. Seventeen intact first premolars scheduled for orthodontic extraction were bleached for 4 h immediately preceding extraction. Fourteen additional premolars from the same individuals were not bleached. All 31 teeth were extracted, fixed, demineralized, frozen, sectioned, and immunostained with anti-HO-1 antibody using a standard ABC protocol. There was no significant difference in the presence of HO-1 between total bleached versus total unbleached teeth using the Fisher's Exact Test (p < or = 0.05). However, the histological findings could be interpreted to suggest that coronal odontoblasts and endothelial cells in the underlying pulp proper may have the potential to respond to oxidative stress by increasing the synthesis of HO-1 (HSP32). This could represent a component of an initial defensive response by specific cells in strategic locations in the pulp that precedes classical inflammatory pathways.

The RecBC enzyme loads RecA protein onto ssDNA asymmetrically and independently of chi, resulting in constitutive recombination activation

Double-strand DNA break repair and homologous recombination in Escherichia coli proceed by the RecBCD pathway, which is regulated by cis-acting elements known as chi sites. A crucial feature of this regulation is the RecBCD enzyme-directed loading of RecA protein specifically onto the 3'-terminal, chi-containing DNA strand. Here we show that RecBC enzyme (lacking the RecD subunit) loads RecA protein constitutively onto the 3'-terminal DNA strand, with no requirement for chi. This strand is preferentially utilized in homologous pairing reactions. We propose that RecA protein loading is a latent property of the RecBCD holoenzyme, which is normally blocked by the RecD subunit and is revealed following interaction with chi.

Noncontact dipole effects on channel permeation. II. Trp conformations and dipole potentials in gramicidin A

The four Trp dipoles in the gramicidin A (gA) channel modulate channel conductance, and their side chain conformations should therefore be important, but the energies of different conformations are unknown. A conformational search for the right-handed helix based on molecular mechanics in vacuo yielded 46 conformations within 20 kcal/mol of the lowest energy conformation. The two lowest energy conformations correspond to the solid-state and solution-state NMR conformations, suggesting that interactions within the peptide determine the conformation. For representative conformations, the electrostatic potential of the Trp side chains on the channel axis was computed. A novel application of the image-series method of. Biophys. J. 9:1160-1170) was introduced to simulate the polarization of bulk water by the Trp side chains. For the experimentally observed structures, the CHARm toph19 potential energy (PE) of a cation in the channel center is -1.65 kcal/mol without images. With images, the PE is -1.9 kcal/mol, demonstrating that the images further enhance the direct dipole effect. Nonstandard conformations yielded less favorable PEs by 0.4-1.1 kcal/mol.

Reconstitution of an SOS response pathway: derepression of transcription in response to DNA breaks

E. coli responds to DNA damage by derepressing the transcription of about 20 genes that make up the SOS pathway. Genetic analyses have shown that SOS induction in response to double-stranded DNA (dsDNA) breaks requires LexA repressor, and the RecA and RecBCD enzymes--proteins best known for their role as initiators of dsDNA break repair and homologous recombination. Here we demonstrate that purified RecA protein, RecBCD enzyme, single-stranded DNA-binding (SSB) protein, and LexA repressor respond to dsDNA breaks in vitro by derepressing transcription from an SOS promoter. Interestingly, derepression is more rapid if the DNA containing the dsDNA break has a chi recombination hot spot (5'-GCTGGTGG-3'), suggesting a novel regulatory role for one of the most overrepresented octamers in the E. coli genome.

Interpersonal violence and the pregnant homeless woman

Homelessness continues to increase in the United States. Families comprise the fastest growing segment of the homeless population, and estimates suggest that women head 90% of homeless families. Pregnant homeless women are exposed to more cumulative violence than are comparable low-income, housed women. Intervention strategies that may improve health care provided to pregnant homeless women include abuse and safety assessment protocols and the use of a hand-carried health record. These interventions are directed at efforts to preserve the woman's autonomy and confidentiality, reduce areas of client-provider conflict, and generally improve encounters between the client and the health care system.

SSB protein controls RecBCD enzyme nuclease activity during unwinding: a new role for looped intermediates

The RecBCD enzyme of Escherichia coli initiates homologous recombination by unwinding and simultaneously degrading DNA from a double-stranded DNA end. Single-stranded DNA loops are intermediates of this unwinding process. Here we show that SSB protein reduces the level of DNA degradation by RecBCD enzyme during unwinding, by binding to these ssDNA intermediates. Prior to interaction with the recombination hot spot chi, RecBCD enzyme has both 3'-->5' exonuclease and a weaker 5'-->3' exonuclease activity. We show that degradation of the 5'-terminal strand at the entry site is much more extensive in the absence of SSB protein. After interaction with chi, the level of 5'-->3' exonuclease activity is increased; as expected, degradation of the 5'-strand is also elevated in the absence of SSB protein. Furthermore, we show that, in the absence of SSB protein, the RecBCD enzyme is inhibited by the ssDNA products of unwinding; SSB protein alleviates this inhibition. These results provide insight into the organization of helicase and nuclease domains within the RecBCD enzyme, and also suggest a new level at which the nuclease activity of RecBCD enzyme is controlled. Hence, they offer new insight into the role of SSB protein in the initiation phase of recombination.

Environmental endocrine disruption: an effects assessment and analysis

This report is an overview of the current state of the science relative to environmental endocrine disruption in humans, laboratory testing, and wildlife species. Background information is presented on the field of endocrinology, the nature of hormones, and potential sites for endocrine disruption, with specific examples of chemicals affecting these sites. An attempt is made to present objectively the issue of endocrine disruption, consider working hypotheses, offer opposing viewpoints, analyze the available information, and provide a reasonable assessment of the problem. Emphasis is placed on disruption of central nervous system--pituitary integration of hormonal and sexual behavioral activity, female and male reproductive system development and function, and thyroid function. In addition, the potential role of environmental endocrine disruption in the induction of breast, testicular, and prostate cancers, as well as endometriosis, is evaluated. The interrelationship of the endocrine and immune system is documented. With respect to endocrine-related ecological effects, specific case examples from the peer-reviewed literature of marine invertebrates and representatives of the five classes of vertebrates are presented and discussed. The report identifies some data gaps in our understanding of the environmental endocrine disruption issue and recommends a few research needs. Finally, the report states the U.S. Environmental Protection Agency Science Policy Council's interim position on endocrine disruption and lists some of the ongoing activities to deal with this matter.

The translocating RecBCD enzyme stimulates recombination by directing RecA protein onto ssDNA in a chi-regulated manner

Double-stranded DNA break repair and homologous recombination in E. coli are initiated by the RecBCD enzyme, which unwinds and simultaneously degrades DNA from a double-stranded DNA end. This process is stimulated by cis-acting DNA elements, known as chi sites. Using both in vitro pairing and nuclease protection assays, we demonstrate that the translocating RecBCD enzyme, which has been activated by chi, coordinates the preferential loading of the homologous pairing protein, RecA, onto the resultant single-stranded DNA downstream of chi. This facilitated loading of RecA protein results in a substantial increase in both the efficiency and rate of in vitro recombination reactions and offers an explanation for stimulation of recombination and repair in vivo by chi.

The recombination hot spot chi is a regulatory element that switches the polarity of DNA degradation by the RecBCD enzyme

Homologous recombination in Escherichia coli is stimulated at DNA sequences known as chi sites. Stimulation requires the multifunctional RecBCD enzyme, which is both a helicase and a 3' --> 5' exonuclease. Upon recognition of a properly oriented chi site, the 3' --> 5' exonuclease activity is attenuated. Here we show that in addition to attenuation of the 3' --> 5' exonuclease activity, recognition of chi by the RecBCD enzyme also up-regulates a nuclease activity of the opposite polarity, resulting in an enzyme that now preferentially degrades 5' --> 3'. These results demonstrate that chi is a unique regulatory element that converts the antirecombinogenic form of the RecBCD enzyme into a recombinogenic form by causing two distinct enzymatic changes: attenuation of the 3' --> 5' nuclease activity, and up-regulation of the 5' --> 3' nuclease activity. The consequence of chi recognition is the production of a recombination intermediate possessing a 3'-ssDNA overhang terminating at the chi sequence. This processing of a dsDNA end to a 3'-ssDNA overhang parallels that which occurs during the initation of homologous recombination in other pathways in E. coli, and in other organisms such as the yeast Saccharomyces cerevisiae.

Three medical schools' responses to the HIV/AIDS epidemic and the effect on students' knowledge and attitudes

PURPOSE

To assess the relative importance of factors influentail by the prevalence of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), such as didactic and clinical training, and the number of HIV-infected individuals known personally, on students' HIV-related knowledge and attitudes.

METHOD

A survey was undertaken of the classes of 1991 and 1994 at the University of Colorado School of Medicine, the University of New Mexico School of Medicine, and the University of South Dakota School of Medicine. The questionnaire contained 40 knowledge questions, 20 attitude questions, and demographic questions. The students reported estimates of HIV-related didactic hours and clinical encounters experienced during their training, as well as the number of HIV-infected individuals known personally. Data analysis employed two-way analysis of variance (ANOVA) and Pearson correlation coefficients.

RESULTS

In 1991 the response rates were 73% from Colorado, 54% from New Mexico, and 50% from South Dakota; in 1994 the rates were 80%, 63%, and 60%, respectively. Training programs were similar between schools and over time, varying only in the amounts of didactic information offered. The 1994 students scored significantly better than did 1991 students on knowledge, overall attitude, fear of infection, and willingness to treat HIV-infected patients; these variables were significantly correlated with the numbers of HIV-infected individuals known personally by the students. Didactic training hours were not significantly correlated with any study variable, and clinical experiences were correlated only with increased knowledge.

CONCLUSION

Differences in HIV/AIDS prevalences did not affect the schools' training programs, but indirectly affected the students' knowledge and attitudes, which were related to the numbers of HIV-infected individuals known personally by the students. The authors recommend that medical schools increase students' opportunities for meaningful personal contact with HIV-infected individuals.

Chi-activated RecBCD enzyme possesses 5'-->3' nucleolytic activity, but RecBC enzyme does not: evidence suggesting that the alteration induced by Chi is not simply ejection of the RecD subunit

BACKGROUND

Homologous recombination in Escherichia coli is initiated by the RecBCD enzyme, and is stimulated by DNA elements known as Chi (chi) sites. The RecBCD enzyme is both a helicase and a nuclease. Recognition of chi causes both attenuation of the 3'-->5' exonuclease activity of the RecBCD enzyme, and activation of an exonuclease activity with 5'-->3' polarity, while leaving the helicase activity unaffected. A variety of evidence suggests that chi-recognition by RecBCD enzyme is accompanied by ejection of the RecD subunit.

RESULTS

Through examination of RecBCD exonuclease activity under a variety of conditions, we have shown that recognition of chi by the RecBCD enzyme results in a net reduction of nuclease activity. In addition, the exact location of the first cleavage event elicited by chi-activation of the 5'-->3' nuclease is dependent upon the concentration of free magnesium ions. Finally, we have demonstrated that purified RecBC enzyme (i.e. without the RecD subunit) possesses no significant exonuclease activity under conditions where the chi-modified RecBCD enzyme is an active 5'-->3' exonuclease.

CONCLUSIONS

We have shown that, despite the activation of a 5'-->3' exonuclease, recognition of chi by the RecBCD enzyme results in a net preservation of DNA. This new chi-activated nucleolytic action shows surprising variability in the exact location of its initial cleavage. We have demonstrated that purified RecBC enzyme is not an exact analogue of the chi-activated RecBCD enzyme, suggesting that the biochemical basis of chi-activation is not simply ejection of the RecD subunit.

Laparoscopic appendectomy versus open appendectomy: a single institution study

PURPOSE

The purpose of this study was to compare the safety and efficacy of laparoscopic appendectomy versus open appendectomy at Baptist Hospital in Miami, Florida.

METHODS

A retrospective review was performed on all appendectomies performed at Baptist Hospital from October 1, 1994 to September 30, 1995. There were a total of 244 cases; 137 open appendectomies and 107 laparoscopic appendectomies. The cases were reviewed with regard to pathology, operating time, length of hospital stay and complications.

RESULTS

The pathologic findings at surgery were similar for the two groups. Concomitant pathology was more likely to be found laparoscopically than in open surgery. There was a greater percentage of ruptured appendices in surgery done via the open method. Operative time was slightly longer, but complications were less in the laparoscopic group. Length of stay was lower in the laparoscopic appendectomy group.

CONCLUSIONS

Although very similar, our method of appendectomy favors the laparoscopic technique.

Homeless women's perceptions about their families of origin

The purpose of this study was to examine descriptively the families of origin of women who are, or who had been, homeless. The research was done using a descriptive qualitative research design; specifically, intensive interviewing. A feminist framework guided the research process. Lofland and Lofland's (1984) conceptualization of units of social settings was used as the basis for analysis of the data. The sample consisted of 20 women who had been homeless. Twelve of the women were interviewed individually. Six of those 12 women and an additional 8 women were later interviewed as part of two focus groups. Themes within each social unit included: meanings--homelesness, home, family of origin, lack of connectedness, and being without; practices--male privilege, transiency, and abuse issues; episodes--loss of family and being homeless; roles--traditional female-male, scapegoating, and little adult; and relationships--mother/daughter, father/daughter, and sibling. Within the mother/daughter relationships, the dominant themes were betrayal, devaluation of self, enmeshment, emotional void, longing for, emotional cutoff, and destructive coalitions. The themes from the father/daughter relationships social unit were abuse issues, differential treatment, idealized father figure, and banished daughter. Criteria for transferability and adequacy were used to determine scientific rigor.

Kawasaki disease associated with streptococcal infection within a family

OBJECTIVE

To describe the illness occurring in four members of a family, which had clinical and laboratory features of Kawasaki disease and streptococcal infection.

METHODOLOGY

A retrospective report of three siblings and an adult male living in one household. The children had serology, blood counts, cultures and echocardiography performed and were treated with antibiotics and gammaglobulin infusions.

RESULTS

The patients developed clinical, and exhibited laboratory, features suggesting streptococcal infection and 4/5 criteria suggesting the diagnosis of Kawasaki disease. All made a good clinical recovery but the youngest developed a coronary artery aneurysm.

CONCLUSIONS

It may be difficult to distinguish streptococcal infection and Kawasaki disease. It is possible that some cases of Kawasaki disease are precipitated by streptococcal infection.