Host condition and accumulation of metals by acanthocephalan parasite Echinorhynchus gadi in cod Gadus morhua from the southern Baltic Sea.

In this study, we analyzed the relationship between concentration of metals in the host-parasite system (cod - acanthocephalan Echinorhynchus gadi) and Fulton's condition factor (FCF) of the host. The relationship between metal (Ca, Cd, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Pb, Sr, Zn) concentrations in E. gadi and cod tissues was expressed as a bioconcentration factor (BCF), the ratio of the concentration in the parasite tissue to that in host tissues. Acanthocephalans accumulated mainly toxic metals (Cd, Pb), as well as Sr, Ca, Na. Cadmium showed the highest bioconcentration in parasites (BCF >200) compared to fish muscle. Significant negative correlation was detected between FCF and the concentration of Cd and Hg in cod liver. In contrast, FCF was positively correlated with the concentration of Hg in acanthocephalan tissues.

Moisture sorption isotherms and glass transition temperature of elecampe (Inula helenium L.) and burdock (Arctium lappa L.) roots at 25°C.

Sorption isotherms of elecampe (Inula helenium L.) and burdock (Arctium lappa L.) root samples were obtained at 25 °C. Elecampe exhibited hysteresis loop in the range of 0.35-0.90 a(w) , whereas burdock roots showed significant differences between adsorption and desorption isotherms from 0.65 to 0.80 a(w) . Blahovec-Yanniotis was considered to give the best fit over the whole range of a(w) tested. Various parameters describing the properties of sorbed water derived from GAB, Henderson and Blahovec-Yanniotis models have been discussed. Differential scanning calorimetric method was used to measure the glass transition temperature (T (g)) of root samples in relation to water activity. The safe moisture content was determined in 12.01 and 14.96 g/100 g d. b. for burdock and elecampe root samples at 25 °C, respectively. Combining the T (g) line with sorption isotherm in one plot, it was found that the glass transition temperature concept overestimated the temperature stability for both root samples.

Contryphans from Conus textile venom ducts.

Contryphans are unusual Conus peptides which contain a distinctive post-translational modification, D-tryptophan or D-leucine. cDNA clones encoding new contryphans from the mollusc-hunting cone snail Conus textile were identified and the inferred mature peptides were synthesized: contryphan-Tx (Gly-Cys-Hyp-D-Trp-Gln-Pro-Tyr-Cys-NH(2)), Leu-contryphan-Tx (Cys-Val-D-Leu-Tyr-Pro-Trp-Cys-NH(2)) and contryphan R/Tx which is identical to contryphan-R [Jimenez et al., 1996. Contryphan is a D-tryptophan containing Conus peptide. J. Biol. Chem. 281, 28002-28005]. Leu-contryphan-Tx exhibits a single peak, but contryphan-Tx shows two peaks under reverse-phase high-performance liquid chromatography conditions. Ultraviolet resonance Raman spectroscopy demonstrates a difference in the D-tryptophan dihedral angle for the two contryphan-Tx equilibrium conformers. Both the sequences and in vivo effects of all contryphans isolated suggest that there are two major branches of the contryphan family.

A critical review of current nursing faculty practice.

PURPOSE: To critically examine the current literature on nursing faculty practice, using the National Organization of Nurse Practitioner Faculties (NONPF) Guidelines for Evaluation of Faculty Practice, and to examine faculty practice models' strengths, weaknesses, and barriers. DATA SOURCES: Thirty-five articles describing models of faculty practice were identified through an exhaustive search on CINAHL and Medline. Two NONPF monographs on nursing faculty practice were used as guidelines for the critical review. CONCLUSIONS: Faculty practice has become an integral component of faculty-role expectations at many schools of nursing. Workload, especially without adequate compensation, remains a hindrance to practice. The value of faculty practice time and expertise has not been sufficiently demonstrated. Integration of practitioner, educator and researcher roles remains extremely difficult and sometimes elusive. IMPLICATIONS FOR PRACTICE: Faculty practice offers many advantages to schools of nursing, including educational and research opportunities for faculty and students, as well as practice sites and affordable community healthcare. Providing health care in the community presents an opportunity for independent and collaborative practice. To fully utilize the great research opportunities provided by faculty practice, more emphasis must be placed on gathering and analyzing descriptive data.

UV resonance raman spectra of ligand binding intermediates of sol-gel encapsulated hemoglobin.

We report for the first time specific conformational changes for a homogeneous population of ligand-bound adult deoxy human hemoglobin A (HbA) generated by introducing CO into a sample of deoxy-HbA with the effector, inositol hexaphosphate, encapsulated in a porous sol-gel. The preparation of ligand-bound deoxy-HbA results from the speed of ligand diffusion relative to globin conformational dynamics within the sol-gel (1). The ultraviolet resonance Raman (UVRR) difference spectra obtained reveal that E helix motion is initiated upon ligand binding, as signaled by the appearance of an alpha14beta15 Trp W3 band difference at 1559 cm(-1). The subsequent appearance of Tyr (Y8a and Y9a) and W3 (1549 cm(-1)) UVRR difference bands suggest conformational shifts for the penultimate Tyralpha140 on the F helix, the "switch" region Tyralpha42, and the "hinge" region Trpbeta37. The UVRR results expose a sequence of conformational steps leading up to the ligation-induced T to R quaternary structure transition as opposed to a single, concerted switch. More generally, this report demonstrates that sol-gel encapsulation of proteins can be used to study a sequence of specific conformational events triggered by substrate binding because the traditional limitation of substrate diffusion times is overcome.

Solution-active structural alterations in liganded hemoglobins C (beta6 Glu --> Lys) and S (beta6 Glu --> Val).

Based upon existing crystallographic evidence, HbS, HbC, and HbA have essentially the same molecular structure. However, important areas of the molecule are not well defined crystallographically (e.g. the N-terminal nonhelical portion of the alpha and beta chains), and conformational constraints differ in solution and in the crystalline state. Over the years, our laboratory and others have provided evidence of conformational changes in HbS and, more recently, in HbC. We now present data based upon allosteric perturbation monitored by front-face fluorescence, ultraviolet resonance Raman spectroscopy, circular dichroism, and oxygen equilibrium studies that confirm and significantly expand previous findings suggesting solution-active structural differences in liganded forms of HbS and HbC distal to the site of mutation and involving the 2,3-diphosphoglycerate binding pocket. The liganded forms of these hemoglobins are of significant interest because HbC crystallizes in the erythrocyte in the oxy form, and oxy HbS exhibits increased mechanical precipitability and a high propensity to oxidize. Specific findings are as follows: 1) differences in the intrinsic fluorescence indicate that the Trp microenvironments are more hydrophobic for HbS > HbC > HbA, 2) ultraviolet resonance Raman spectroscopy detects alterations in Tyr hydrogen bonding, in Trp hydrophobicity at the alpha1beta2 interface (beta37), and in the A-helix (alpha14/beta15) of both chains, 3) displacement by inositol hexaphosphate of the Hb-bound 8-hydroxy-1,3,6-pyrenetrisulfonate (the fluorescent 2,3-diphosphoglycerate analog) follows the order HbA > HbS > HbC, and 4) oxygen equilibria measurements indicate a differential allosteric effect by inositol hexaphosphate for HbC approximately HbS > HbA.

The conformational and dynamic basis for ligand binding reactivity in hemoglobin Ypsilanti (beta 99 asp-->Tyr): origin of the quaternary enhancement effect.

Hemoglobin Ypsilanti (HbY) is a stable tetrameric hemoglobin that binds oxygen with little or no cooperativity and with high affinity [Doyle, M. L., et al. (1992) Proteins: Struct., Funct., Genet. 14, 351-362]. It displays an especially large quaternary enhancement effect. An X-ray crystallographic study [Smith, F. R., et al. (1991) Proteins: Struct., Funct., Genet. 10, 81-91] of the carboxy derivative of this hemoglobin (COHbY) revealed a new quaternary structure that partially resembles the recently described R2 structure [Silva, M. M., et al. (1992) J. Biol. Chem. 267, 17248-17256]. Very little is known about either the solution phase conformations of the liganded and deoxy forms of HbY or the molecular basis for the large quaternary enhancement effect (Doyle et al., 1992). In this study, near-IR absorption, Soret-enhanced Raman, and UV (229 nm) resonance Raman spectroscopies are used to probe the liganded and deoxy derivatives of HbY in solution. Nanosecond time-resolved near-IR absorption measurements are used to expose the relaxation properties of the photoproduct of COHbY. Time-resolved (Soret band) absorption is used to generate the geminate and solvent phase ligand rebinding curves for photodissociated COHbY. The spectroscopic results indicate that COHbY has an R-like conformation with respect to both the proximal heme pocket and the hinge region of the alpha 1 beta 2 interface. The deoxy derivative of HbY has spectroscopic features that are very similar to those observed for species assigned to the deoxy R or half-liganded R conformations of human adult hemoglobin (HbA). The 10 ns to 100 micros relaxation properties of the photoproduct of COHbY are distinctly different from those of HbA in that for HbY, little if any tertiary or quaternary relaxation is observed. The near-absence of relaxation in the HbY photoproduct explains the differences in the geminate and solvent phase CO recombination between HbA and HbY. The impact of the conformational and relaxation properties of HbY on the geminate rebinding process forms the basis of a model that accounts for the large quaternary enhancement effect reported for HbY (Doyle et al., 1992). In addition, the spectroscopic data and the X-ray crystallographic results explain the slow relaxation for HbY and the near-absence of cooperative ligand binding for this protein based on the behavior of the penultimate tyrosines.

Adolescent development: setting the stage for influencing health behaviors.

Adolescent development is viewed as the overarching framework for approaching disease prevention and health promotion. This chapter is a review of salient developmental issues in adolescence, identification of the potential effects of adolescent development on health behaviors, identification of conceptual and theoretical frameworks to address the behaviors, and suggestions for the timing and tailoring of interventions to prevent health risk behaviors and promote health.

School-based health center utilization: a survey of users and nonusers.

BACKGROUND: As school-based health centers (SBHCs) continue to grow, it remains important to study use of the centers. The extent to which mental health problems exist in the students with access to the centers, whether those students are using the available services, if they are satisfied with the services, and the reasons for nonuse by those students who do not enroll are all meaningful questions. METHODS: The above issues were studied in an urban high school with a 2-year-old SBHC by administering questions during physical education classes on health center use and mental health concerns. The 630 respondents were 45% male, 55% female, 61% black, 29% Hispanic, 54% in grades 9 or 10, 46% in grades 11 or 12. RESULTS: Sixty percent of the students were registered in the SBHC; 40% were not registered. Seventy-five percent of registered students reported average use (< or =3 visits); females were more likely than males (P=.017) to be frequent (>3 visits) users of SBHC services. Mental health problems among all participants included depression in 31%, use of alcohol 1 time or more per month in 21%, use of alcohol daily in 5%, suicidal ideation in 16%, history of a suicide attempt in 10%, knowing someone who had been murdered in 50%, and being in at least 1 fight at school in 26%. Frequent users, average users, and nonusers did not differ by age, grade, race, or any of the measured mental health problems. Among the 472 students who completed the survey section on SBHC perceptions, 305 described health center use: 92% were satisfied with health center services, 79% were comfortable being seen in the SBHC, 74% believed visits were kept confidential, 61% told their parents about each visit, and 51% considered the SBHC their regular health care source. The health center was used for mental health services by 34% and sexuality-related care by 15%. The 167 students who described reasons for not using the SBHC most frequently reported that they already had a physician (60%), did not need it (50%), prefer continuing previous health care (45%), did not get around to it (30%), parents were opposed (20%), were not comfortable (19%), did not know about the service (19%), and did not want problems known (19%). CONCLUSIONS: We conclude that, in this urban high school, (1) average users, frequent users, and nonusers did not differ in the mental health problems measured in this study; (2) those who used the SBHC indicated strong satisfaction with the care received; and (3) those who did not use the SBHC chose to stay away for a variety of reasons, most commonly the availability of other care or the perception of lack of need.

Mental health care in a high school based health service.

This paper describes the mental health services provided at a high school based health center that integrates mental health and medical services. Five years after the inception of the center in 1988, mental health visits had quadrupled. In 1992 alone, students made 1,002 mental health visits. Strikingly, one-third of these students reported problematic substance use among other family members. Other leading reasons for utilizing mental health services included pregnancy (19%), past or present suicidal ideation (14%), obesity (8.7%), ongoing depression (8%), and issues related to sexuality (7.5%).

Business and faith: key community partnerships for school-based health centers.

School-based health centers need to form partnerships with organizations in the community. These relationships are essential to the viability of the centers because they can provide support and resources. However, benefits should be accrued by all partners, not just the health centers. Although there are many communities for school-based health centers to connect to, this article focuses on two integral ones--communities of business and faith. Key findings from a project formed to develop communication strategies and to generate support from the business community are reviewed. Recommendations for school-based health centers in approaching the business community are provided. Similarities and differences between communities of faith and strategies of develop relationships with these communities are presented. School-based health centers are encouraged to understand the characteristics and priorities of their partners in communities of business and faith, and to pursue strong relationships with both communities.

Rapid loop dynamics of Yersinia protein tyrosine phosphatases.

The Yersinia protein tyrosine phosphatases (PTPase) contain a single and invariant tryptophan (W354) located at one of the hinge positions of the flexible loop (WpD loop), which is essential for catalysis. The wild-type Yersinia PTPase and an active site mutant in which the esential Cys 403 has been replaced by serine (C403S) have been examined using both time-resolved fluorescence anisotropy and steady-state UV resonance Raman (UVRR) spectroscopies. Both enzymes were examined with and without the bound inhibitor arsenate. The UVRR spectra indicate that in solution the ligand-free, wild-type PTPase exists as an equilibrium mixture of two tryptophan rotamer structures with chi2,1 dihedral angles of -4 degrees and -90 degrees. The two rotamers have been attributed to the presence of both "closed" and "open" WpD loop conformers of the ligand-free enzyme. Conversely, the UVRR spectra of the arsenate-ligated, wild-type PTPase and of ligand-free and arsenate-ligated C403S PTPase contain a single W3 band which is correlated to the -4 degrees rotamer of W354, indicating a predominance of the closed WpD loop conformer. The tryptophan fluorescence anisotropy decay measurements of the ligand-bound, wild-type Yersinia PTPase and of both ligation states of the C403S PTPase reveal a single correlation time of 30-48 ns due to the rotational motion of the protein, while the ligand-free, wild-type PTPase is found to have two correlation times of 31 and 3.8 ns. The 3.8 ns correlation time of the ligand-free enzyme is attributed to the hinged movement of the WpD loop which contains W354. These results indicate that under physiological conditions, the nonligated, wild-type Yersinia PTPase alternates between an open WpD loop and a closed loop form with a rate constant of approximately 2.6 x 10(8) s(-1). We conclude that the rate of WpD loop closure of the wild-type Yersinia PTPase is thus independent of the presence of ligand, whereas in the presence of ligand the rate of opening is dramatically reduced resulting in a closed conformation on ligand binding. In contrast, the ligand-free and ligated C403S PTPase remain in the loop closed configuration over the time course of our dynamic measurements. The lack of WpD loop motion in the C403S PTPase is believed to be due to either a loss of repulsive potential between the anionic thiolate and Asp 356 of the WpD loop and/or the formation of a hydrogen bond or water bridged hydrogen bond between Ser 403 and Asp 356.

Probing the hemoglobin central cavity by direct quantification of effector binding using fluorescence lifetime methods.

Time-resolved fluorescence methods have been used to show that 8-hydroxy-1,3,6-pyrenetrisulfonate (HPT), a fluorescent analog of 2,3-diphosphoglycerate, binds to the central cavity of carboxyhemoglobin A (HbACO) at pH 6.35. A direct quantitative approach, based on the distinctive free and bound HPT fluorescent lifetimes of 5.6 ns and approximately 27 ps, respectively, was developed to measure the binding affinity of this probe. HPT binds to a single site and is displaced by inositol hexaphosphate at a 1:1 mol ratio, indicating that binding occurs at the 2,3-diphosphoglycerate site in the central cavity. Furthermore, the results imply that low pH HbACO exists as an altered R state and not an equilibrium mixture of R and T states. The probe was also used to monitor competitive effector binding and to compare the affinity of the binding site in several cross-bridged HbA derivatives.

Promoting the nurse practitioner role in managed care.

Managed care poses opportunities for nurse practitioners, providing they successfully negotiate new health care systems. This requires being familiar with Medicaid waivers and state policies regarding health insurance. In addition, knowledge of credentialing and compensation mechanisms under managed care enhances nurse practitioners' ability to forge provider roles. Because of the overlap between priorities of nurse practitioner practice and managed care, nurse practitioners have the potential to strengthen their roles as primary and specialty care providers in traditional and nontraditional settings.

Sports participation in an urban high school: academic and psychologic correlates.

PURPOSE: To study positive and negative correlates of sports participation in inner-city youth. METHODS: We distributed anonymous questionnaires to 838 students in gym classes of an urban New York City High School. Forty five percent of students were male and 55% female, with mean age 16.0 years; 64% in grades 9-10, and 36% in grades 11-12; 63% black, 27% Hispanic, and 10% other; and 30% A/B students, 38% C students, and 32% D/F students. RESULTS: All students reported some involvement in sports: 37% in 1-2 sports, 29% in 3-4 sports 24% in > or = 5 sports; 20% played on local teams, and 12% on junior or senior varsity. Approximately one-third each reported no weekday sports participation (30%), 1-2 hours per day (34%), or > or = 3 hours (36%); and 34% reported no participation on weekends, 26% reported 1-2 hours per day, and 40% > or = 3 hours. Basketball, volleyball, baseball, and weight lifting were the most common sports. Enjoyment, recreation, and competition were the most commonly reported reasons for participation. While 86% of subjects considered school "extremely" or "very" important, 35% considered sports "extremely" or "very" important. However, many believed they would "definitely" or "probably" receive an athletic scholarship (52% males, 20% females). Males reported more (p < .05) weekday, weekend, and team participation, and greater expectations (p <.001) of a future in sports. Sports involvement was not statistically associated with academic performance or scores on either the Rosenberg Self-Esteem Scale or Depression Self Rating Scale. Steroid use, at least once, was reported by 11% of males and 4% of females. Thirteen percent of students (21% males, 6% females) tried to gain weight for sports and 20% of both males and females tried to lose. Sports injuries within the past year were reported by 15% of students, and approximately three-quarters could correctly answer each of five questions about basic first aid. CONCLUSIONS: The data indicate that most of these urban youth had athletic involvement, many had unrealistic expectations for their futures, and some utilized unhealthy behaviors in an attempt to enhance performance. Among these students, no association was found between sports involvement and academic performance, self-esteem, or depression.

Back to school: training opportunities in school-based health centers.

School-based health centers are a rapidly growing model for provision of comprehensive, primary health care to elementary, middle, and senior high school students. They offer an exciting new training opportunity that is nontraditional, multidisciplinary, and relevant to future practice. The programs funded by the Robert Wood Johnson Foundation found that trainees made a significant contribution to their projects. The value of school-based health centers as training sites extends to trainees, schools, and the future growth of school-based health centers. Integration of medical and mental health services and delivery of services by a multidisciplinary team are essential components of school-based health centers. These characteristics make school sites well suited to the training needs and practice opportunities sought by a number of disciplines, including developmental and behavioral pediatrics. A school-based health center rotation may be particularly important in developmental and behavioral pediatrics because many trainees may be called on to consult with schools in their future careers, and this rotation may provide their only school-related experience.

School-based adolescent health care. Review of a clinical service.

OBJECTIVE: To provide recommendations regarding the establishment and maintenance of school-based clinics, based on analysis of data from a clinic located in a New York City high school. DESIGN: Review of demographic, medical, and psychosocial data collected during student visits. SUBJECTS: During 2 1/2 years, 1283 students were seen. The students were 53% girls and 47% boys; 65% black and 25% Hispanic; and 65% grades 9-10 and 35% grades 11-12. RESULTS: There were 7920 visits. Visits were for acute or chronic medical problems (44%), physical examinations and immunizations (25%), gynecologic or sexuality-related issues (17%), and mental health concerns (14%). Psychosocial characteristics of the 378 students who enrolled during the 1989-1990 academic year indicated that only 27% lived with both natural parents, 55% were foreign-born, 37% had repeated a grade at least once, 44% were sexually active, 13% drank alcohol, and 14% had past or present suicidal ideation. CONCLUSIONS: These data demonstrate that a school-based clinic can be involved in the management of a wide range of health care needs for large numbers of at-risk youth. In addition, school-based clinics can serve as a major site for the teaching of medical students and residents, and as a valuable resource for clinical research.

Orientation and linear dichroism of Mastigocladus laminosus phycocyanin trimer and Nostoc sp. phycocyanin dodecamer in stretched poly(vinyl alcohol) films.

The linear dichroism (LD) spectra of the C-phycocyanin (C-PC) trimer disks oriented in poly(vinyl alcohol) films (PVA) at room temperature and at 95 K were determined. Utilizing the known atomic coordinates of the chromophores (Schirmer, T., Bode, W. and Huber, R. (1987) J. Mol. Biol. 196, 677-695) and theoretical estimates of the orientations of the transition dipole moments relative to the molecular framework, the LD spectra were simulated using the pairwise exciton interaction model of Sauer and Scheer (Biochim. Biophys. Acta 936 (1988) 157-170); in this model, the alpha 84 and beta 84 transition moments are coupled by an exciton mechanism, while the beta 155 chromophore remains uncoupled. Linear dichroism spectra calculated using this exciton model, as well as an uncoupled chromophore (molecular) model, were compared with experimental LD spectra. Satisfactory qualitative agreement can be obtained in both the exciton and molecular models using somewhat different relative values of the theoretically estimated magnitudes of the beta 155 oscillator strength. Because the relative contributions of each of the chromophores (and thus exciton components) to the overall absorption of the C-PC trimer are not known exactly, it is difficult to differentiate successfully between the molecular and exciton models at this time. The linear dichroism spectra of PC dodecamers derived from phycobilisomes of Nostoc sp. oriented in stretched PVA films closely resemble those of the C-PC trimers from Mastigocladus laminosus, suggesting that the phycocyanin chromophores are oriented in a similar manner in both cases, and that neither linker polypeptides nor the state of aggregation have a significant influence on these orientations and linear dichroism spectra. The LD spectra of oriented phycocyanins in stretched PVA films at low temperatures (95 K) appear to be of similar quality and magnitude as the LD spectra of single C-PC crystals (Schirmer, T. and Vincent, M.G. (1987) Biochim. Biophys. Acta 893, 379-385).