Chytrid infections exhibit historical spread and contemporary seasonality in a declining stream-breeding frog.

Species with extensive geographical ranges pose special challenges to assessing drivers of wildlife disease, necessitating collaborative and large-scale analyses. The imperilled foothill yellow-legged frog (Rana boylii) inhabits a wide geographical range and variable conditions in rivers of California and Oregon (USA), and is considered threatened by the pathogen Batrachochytrium dendrobatidis (Bd). To assess drivers of Bd infections over time and space, we compiled over 2000 datapoints from R. boylii museum specimens (collected 1897-2005) and field samples (2005-2021) spanning 9° of latitude. We observed a south-to-north spread of Bd detections beginning in the 1940s and increase in prevalence from the 1940s to 1970s, coinciding with extirpation from southern latitudes. We detected eight high-prevalence geographical clusters through time that span the species' geographical range. Field-sampled male R. boylii exhibited the highest prevalence, and juveniles sampled in autumn exhibited the highest loads. Bd infection risk was highest in lower elevation rain-dominated watersheds, and with cool temperatures and low stream-flow conditions at the end of the dry season. Through a holistic assessment of relationships between infection risk, geographical context and time, we identify the locations and time periods where Bd mitigation and monitoring will be critical for conservation of this imperilled species.

A qualitative study of fourteen African countries' nursing workforce and labour market.

AIM: The aim of this study was to describe factors affecting nursing education and labour markets in countries in East, Central, and Southern Africa, and critical areas for investment. BACKGROUND: An understanding about the relationship between the supply of nurses (determined by types of educational programmes, and the quantity and quality of nurse graduates), and workforce demand is critical to health policy development. METHODS: Six focus groups and 14 key informant interviews with nursing leaders and experts were conducted. Participants included government chief nursing officers, registrars of regulatory bodies, association leaders and heads of nursing education. The data were transcribed, coded and analysed using inductive techniques. FINDINGS: Participants discussed challenges and strengths of nursing education, school and regulatory infrastructure, financing mechanisms for the nursing workforce, the state of nursing jobs and scope of nursing practice. CONCLUSION: Strengthened regulations and leadership are needed to improve investment in nursing, the quality of nursing education, and working conditions and to promote the achievement of better health outcomes. IMPLICATIONS FOR NURSING POLICY: Clarifying scope of practice for nurses in the health sector and creating competency-based requirements is important. Governments should establish positions that align with updated competencies and provide fair and safe working conditions. The current and ongoing investment case for nursing requires improved data systems and a commitment to use labour market data for decision-making.

The 1999-2000 ACC task analysis of nurse-midwifery/midwifery practice: a consideration of the concept of professional issues.

The American College of Nurse-Midwives (ACNM) Certification Council periodically conducts a task analysis study as evidence supporting the content validity of the national certification examination in nurse-midwifery and midwifery. The purpose of this article is to report findings related to the examination of the relationship between professional issues and safe beginning-level midwifery as measured by the 1999-2000 Task Analysis of American Nurse Midwifery and Midwifery Practice. Study findings suggest that newly certified midwives place strong emphasis on the importance of tasks related to the ACNM "Hallmarks of Midwifery," which characterize the art and science of the profession: these include tasks dealing with health promotion and cultural competency. The beginning midwives, however, gave consistently low ratings to tasks related to ACNM "Core Competencies" that mirror the professional responsibilities of midwives; these include tasks related to the history of midwifery, research, or health policy. The study has implications for nurse-midwifery/midwifery educators, experienced midwifery mentors, and other persons interested in reinforcing the relevance of these important professional issues to the new midwife.

Considering technology: living and working in a technocratic society.

In this article, a framework is provided for consideration of technologies that are frequently viewed as either a source of power or frustration. The two widely accepted paradigms of technological and social determinism are analyzed in relationship to women's health care. Those ascribing to the model of technological determinism believe that a technology, once created, takes on a life of its own. Those believing in social determinism view a technology as a neutral tool that can be used in any way that the user desires. Finally, a third model that addresses both of these propensities in conjunction with the technology and social factors underlying its use is presented and recommended for critical analysis of devices used when caring for women.

Using surface electrodes to monitor the electric-pulse-induced permeabilization of porcine skin.

The stratum corneum, the outermost layer of the skin, acts as a barrier between the skin and the outside world, preventing evaporation of water from underlying tissues while impeding the diffusion of foreign molecules into the body (1,2). Densely packed layers of flattened, dead, keratinized cells (2,3) are incorporated into a lipid lamellae matrix consisting primarily of ceramides, cholesterol, and fatty acids (2,4), forming an impermeable, hydrophobic partition. The stratum corneum represents the main obstacle to efficient transdermal drug delivery (1,2). If the stratum corneum is disrupted, the barrier to molecular transport is greatly reduced.

Transdermal delivery using surface electrodes in porcine skin.

The main barrier to cutaneous or transcutaneous drug and gene delivery is the impermeability of the stratum corneum (SC), the outermost layer of the skin (1). If the integrity of the SC is disrupted, the barrier to molecular transit may be greatly reduced. Cutaneous absorption can be increased by removal of the SC by tape-stripping or dermabrasion, by vehicle (solvent-carrier) optimization, or by the use of penetration enhancers like DMSO (dimethylsulfoxide), oleic acid, and alcohols (2,3). An electric field can also be used to enhance delivery. Disruption of the SC can be achieved by electroporation, which is the creation of penetration sites by an electric pulse. Ions and molecules move through induced gaps of the SC by diffusion and electromotive or electroosmotic transport (4-6). Electroporation differs from iontophoresis, in which there is an increased migration of ions or charged molecules through the skin when an electrical potential gradient is applied. The primary transdermal route for iontophoresis seems to be appendageal or intercellular through preexisting pathways (5,7), or as a result of low-voltage (<5 V) induced permeabilization of appendageal bilayers (8). A third form of electroenhanced drug delivery, electrochemotherapy (9), refers to localized delivery of electric pulses across a tumor following systemic or intratumor drug administration, and usually does not involve cutaneous or transcutaneous delivery.

Developmental, cognitive, and behavioral sequelae of child abuse.

There is growing interest in the neurologic, behavioral, and cognitive effects of child abuse and neglect. This article explores the literature on the short and long term sequelae of physically and sexually abused and neglected children, along with controversies generated by the studies themselves. Recommendations are made for swift and ongoing intervention in cases of child abuse to protect young victims from potentially devastating effects.

Therapeutic touch. A viable link to midwifery practice.

Through the use of their hands, their intelligence, and their compassion, midwives have traditionally taken a noninterventionist approach to labor and childbirth. Therapeutic Tough, known by its practitioners as simply TT, is a contemporary healing modality through which a practitioner's hands are used to facilitate healing. Midwives and practitioners of TT share an appreciation of the value of a holistic and noninterventionist approach to maintaining patient health. This article explores the potential use of TT as a tool to complement the practice of midwifery. It provides an explanation of the theories underlying TT, the history of its development, and the process involved in its practice. Additionally, the results of studies both supportive and critical of the practice of TT are analyzed. Finally, possible applications of TT to the practice of midwifery are suggested.

Increased DNA synthesis in INIT/10T1/2 cells after exposure to a 60 Hz magnetic field: a magnetic-field or a thermal effect?

This study was designed to test the hypothesis that a 0.1-0.8-mT 60 Hz magnetic field may act as a promoter of carcinogenesis. C3H 10T1/2 mouse fibroblasts initiated with the carcinogen methylcholanthrene (INIT/10T1/2 cells) were used; in these cells, expression of the carcinogenic phenotype is suppressed indefinitely by the presence of retinyl acetate in the culture medium. After withdrawal of retinyl acetate, expression of the carcinogenic phenotype may be observed as the loss of contact inhibition. Cells grown without retinyl acetate were exposed to 0.1-0.8-mT (rms) 60 Hz magnetic fields or to sham fields. Eight days after exposure, magnetic-field and sham-exposed cells showed the same levels of incorporation of [3H]thymidine, and both had counts significantly higher than those of unexposed cells. The rate of incorporation of [3H]thymidine was very sensitive to small (0.1-0.8 degrees C) and transient (60 min) increases in incubation temperature during the first few days of withdrawal of retinyl acetate. Exposure of Jurkat (human acute T-cell lymphoma) and GH3 (rat pituitary tumor) cells to magnetic fields and sham conditions yielded similar results. INIT/10T1/2 cells cultured in the presence of retinyl acetate showed no effect of exposure conditions. Both magnetic-field and sham exposures caused a slight increase in temperature within the exposure zone in the incubator. Thus the differences between rates of incorporation of [3H]thymidine in magnetic field-exposed, sham-exposed and unexposed cells seem to be attributable at least in part to a slight elevation in temperature during exposure. Since some cells appear to be extremely sensitive to small increases in temperature, measurements of magnetic-field effects must be made and interpreted with caution.

Electrorheological modeling of the permeabilization of the stratum corneum: theory and experiment.

Experimentally observed changes in the conductivity of skin under the influence of a pulsing electric field were theoretically analyzed on the basis of a proposed electrorheological model of the stratum corneum (SC). The dependence of relative changes in conductivity on the amplitude of electric field and timelike parameters of applied pulses or pulse trains have been mathematically described. Statistical characteristics of phenomena of transient and long-term electroporation of SC were taken into consideration. The time-dependent decreases of skin resistance depicted by the models were fitted to experimental data for transient and long-term skin permeabilization by electric pulses. The results show two characteristic times and two spectra of characteristic energies for transient and long-term permeabilizations. The rheological parameters derived from the fittings agreed with those reported elsewhere for biological membranes.

Midwifery education models. A contemporary review.

Midwifery education has a rich tradition of blending innovation with educational methods that have demonstrated their value to the profession. Examples of innovations that have influenced midwifery education include the use of the asynchronous modular system, the development of distance methodologies, and most recently the use of computer and telecommunications technologies to mediate education. This study was designed to explore trends in approaches to the education of midwives in both traditional and distance education programs. Program directors were surveyed and interviewed to assess their degree of instructional synchrony, their use of distance modalities, and their predominate methods of curriculum presentation. Results of the survey suggest that programs are using a variety of these approaches to educate their students. Decisions to integrate new educational technologies appear to be based on institutional values, community resources, and student needs.

A pulsed electric field enhances cutaneous delivery of methylene blue in excised full-thickness porcine skin.

We used electric pulses to permeabilize porcine stratum corneum and demonstrate enhanced epidermal transport of methylene blue, a water-soluble cationic dye. Electrodes were placed on the outer surface of excised full-thickness porcine skin, and methylene blue was applied to the skin beneath the positive electrode; 1 ms pulses of up to 240 V were delivered at frequencies of 20-100 Hz for up to 30 min. The amount of dye in a skin sample was determined from absorbance spectra of dissolved punch biopsy sections. Penetration depth and concentration of the dye were measured with light and fluorescence microscopy of cryosections. At an electric exposure dose VT (applied voltage x frequency x pulse width x treatment duration) of about 4700 Vs, there is a threshold for efficient drug delivery. Increasing the applied voltage or field application time resulted in increased dye penetration. Transport induced by electric pulses was more than an order of magnitude greater than that seen following iontophoresis. We believe that the enhanced cutaneous delivery of methylene blue is due to a combination of de novo permeabilization of the stratum corneum by electric pulses, passive diffusion through the permeabilization sites, and electrophoretic and electroosmotic transport by the electric pulses. Pulsed electric fields may have important applications for drug delivery in a variety of fields where topical drug delivery is a goal.

Midwife and nurse-midwife. The effect of title on perception and confidence in services provided by professional midwives. The Midwifery Research Project Group.

This study surveyed individuals in the communities of nurse-midwifery students. Students, identifying themselves as graduate students doing a telephone survey in the area of health care, posed 56 questions to 200 individuals living in New York, North Carolina, Massachusetts, and Nebraska. Survey questions were designed to assess the awareness of the terms midwife and nurse-midwife. Additionally, the survey assessed the sample's perception of the range of services provided by midwives and nurse-midwives, as well as its confidence in having these services provided by a midwife or a nurse-midwife. Demographic data were collected to describe the sample and determine the effects of age, gender, marital status, income, and race on perception and confidence with services. There was a statistically significant relationship between stated familiarity with the terms midwife and nurse-midwife and perception of scope of services and confidence in services. Increased familiarity with the terms midwife and nurse-midwife coincided with a more accurate perception of the scope of services provided by both midwives and nurse-midwives and greater confidence in services provided by midwives and nurse-midwives. Demographic factors studied did not impact on either perception or confidence in services. The data in the survey reveal a large proportion of individuals who report being uncertain about midwives' and nurse-midwives' level of education, scope of services, and relationship to the health care system. This suggests that consumer education could have a sharp impact on shaping the public perception of both midwives and nurse-midwives.

The effect of tacrolimus (FK506) on intestinal barrier function and cellular energy production in humans.

BACKGROUND & AIMS: The maintenance of the intestinal mucosal barrier may be energy dependent. Tacrolimus is a potent immunosuppressive drug that decreases mitochondrial adenosine triphosphate production and increases intestinal permeability in animals. METHODS: Twelve liver graft recipients receiving tacrolimus, 9 healthy volunteers, and 5 liver graft recipients not receiving immunosuppression underwent a combined absorption-permeability-mitochondrial function test using 5 g lactulose, 1 g L-rhamnose, 0.5 g D-xylose, 0.2 g 3-O-methyl-D-glucose, 1 mg/kg 2-keto[1-13C]isocaproic acid ([13C]KICA), and 20 mg/kg L-leucine. The respiratory quotient and resting energy expenditure were measured by indirect calorimetry. Tacrolimus pharmacokinetic profiles and levels of endotoxin and IgM and IgG endotoxin core antibodies were determined. RESULTS: Tacrolimus inhibited the decarboxylation of [13C]KICA, the resting energy expenditure, and the respiratory quotient in an exposure-dependent manner, suggesting an inhibition of mitochondrial respiration. Tacrolimus inhibited intestinal absorptive capacity in an exposure-dependent manner. Tacrolimus-treated patients had an increased intestinal permeability and significantly higher endotoxin levels compared with healthy volunteers. CONCLUSIONS: Tacrolimus inhibits cellular energy production in humans at clinically relevant doses. This is associated with an increased intestinal permeability, endotoxemia, and an impaired intestinal absorptive capacity.

Absence of 60-Hz, 0.1-mT magnetic field-induced changes in oncogene transcription rates or levels in CEM-CM3 cells.

Our objective was to assess the reproducibility of the 60-Hz magnetic field-induced, time-dependent transcription changes of c-fos, c-jun and c-myc oncogenes in CEM-CM3 cells reported by Phillips et al. (Biochim. Biophys. Acta, 1132 (1992) 140-144). Cells were exposed to a 60-Hz magnetic field (MF) at 0.1 mT (rms), generated by a pair of Helmholtz coils energized in a reinforcing (MF) mode, or to a null magnetic field when the coils were energized in a bucking (sham) mode. After MF or sham exposure for 15, 30, 60 or 120 min, nuclei and cytoplasmic RNA were extracted. Transcription rates were measured by a nuclear run-on assay, and values were normalized against either their zero-time exposure values, or against those of the c-G3PDH (housekeeping) gene at the same time points. There was no significant difference, at P=0.05, detected between MF and either sham-exposed or control cells at any time point. Transcript levels of the oncogenes were measured by Northern analysis and normalized as above. No significant difference (P=0.05) in transcript levels between MF and either sham-exposed or control cells was detected.

Characterization of electric-pulse-induced permeabilization of porcine skin using surface electrodes.

We measured the transient and long-term changes of permeability of full-thickness porcine skin after the application of a single or a train of electric pulses, as the basis for optimization of the electrical parameters for enhancing transdermal drug or gene delivery by electroporation. Two electrodes were attached to the stratum corneum of excised skin for transdermal electric pulse delivery and impedance measurement. Both transient and long-term permeabilization were found to be dependent on the electrical exposure dose, i.e., the product of pulse voltage and cumulative pulsing (exposure) time. Skin resistance dropped to about 20% of its prepulsing value when pulsed beyond a critical dosage of 0.4 V-s (with 20-40 V across each skin path), but recovered rapidly within seconds after the pulse. Long-term permeabilization of the skin required repeated pulsing with a minimum potential of 160 V (80 V across each skin path). The maximum long-term resistance drop, to 35% of the initial value, required a dose greater than 200 V-s, recovering slowly and seldom completely in tens of minutes to hours. The decrease and recovery of the resistance were dependent on the frequency and pulse length only for low-dose electrical exposure.

Photosensitization of murine tumor, vasculature and skin by 5-aminolevulinic acid-induced porphyrin.

The effects of topical and systemic administration of 5-aminolevulinic acid (ALA) were examined in several murine tumor systems with regard to porphyrin accumulation kinetics in tumor, skin and blood, vascular and tumor cell photosensitization and tumor response after light exposure. Marked, transient increases in porphyrin levels were observed in tumor and skin after systemic and topical ALA. Rapid, transient, dose-dependent porphyrin increases were also observed in blood; these were pronounced after systemic ALA injection and mild after topical application. They were highest within 1 h after ALA injection, thereafter declining rapidly. This matched the clearing kinetics of injected exogenous protoporphyrin IX (PpIX). Initially, vascular photosensitivity changed inversely to blood porphyrin levels, increasing gradually up to 5 h post-ALA, as porphyrin was clearing from the bloodstream. This pattern was again matched by injected, exogenous PpIX. After therapeutic tumor treatment vascular disruption of the tumor bed, while observed, was incomplete, especially at the tumor base. Minimal direct tumor cell kill was found at low photodynamic therapy (PDT) doses (250 mg/kg ALA, 135 J/cm2 light). Significant, but limited (< 1 log) direct photodynamic tumor cell kill was obtained when the PDT dose was raised to 500 mg/kg systemic ALA, followed 3 h later by 270 J/cm2, a dose that was however toxic to the animals. The further reduction of clonogenic tumor cells over 24 h following treatment was moderate and probably limited by the incomplete disruption of the vasculature. Tumor responses were highest when light treatment was carried out at the time of highest tumor porphyrin content rather than at the time of highest vascular photosensitivity. Tumor destruction did not reach the tumor base, regardless of treatment conditions.

The use of cannulated screws in musculoskeletal trauma. A review of surgical techniques.

The use of minimally invasive techniques for the treatment of articular and periarticular fractures is becoming more popular, especially when formal open reduction and internal fixation is contraindicated because of associated soft-tissue compromise and swelling. Cannulated screws are frequently effective in these situations and can be inserted by way of limited open or percutaneous techniques in many cases. Accurate fracture reduction can be attained through insertion of cannulated screws over a guide pin, resulting in provisional stability of the fracture. In most instances, such methods of fracture reduction are adjunctive and require the addition of external fixation, limited internal fixation, and cast bracing or orthotic considerations. Applications of cannulated screw fixation in specific trauma injuries are discussed as are indications, contraindications, advantages, and disadvantages of such methods.

Measurements of 2H and 18O in body water: analytical considerations and physiological implications.

Measurement of energy expenditure with doubly-labelled water and of body composition and breast milk output with 2H or 18O requires accurate and precise techniques for measuring isotopic enrichments. The possibility of an inaccuracy in measurements of 2H and 18O isotopic enrichment arising from the matrix in biological fluids was investigated (1) by simulating a dilution experiment in both water and urine samples and (2) by reconstituting urine samples, ranging from 10 to 60 g/kg in solid concentration, from freeze-dried urinary solids mixed with either natural abundance or doubly-labelled water. Current techniques involved in measuring 2H and 18O isotopic enrichments were used (reduction of the samples to H2 gas with either Zn or U, and CO2/H2O equilibration or direct measurement of mass 20:18 ratios on water vapour for 18O analysis). All four methods accurately measured serial dilutions in both urine and water. Dilution space calculated from isotopic enrichments, compared with the water content of urine (determined by freeze-drying and accounting for exchangeable isotopes) was overestimated by about 2.4% by the Zn technique whereas other methods were accurate. The urinary solids content of a water solution was related to that inaccuracy. The use of the Zn technique with biological samples is likely to create biases in 2H distribution space. Examination of recent literature supports this view. Caution should therefore be used when physiological conclusions have to be made from the relative size of 2H and 18O distribution spaces.