rIFN-gamma-mediated growth suppression of platinum-sensitive and -resistant ovarian tumor cell lines not dependent upon arginase inhibition.

BACKGROUND: Arginine metabolism in tumor cell lines can be influenced by various cytokines, including recombinant human interferon-gamma (rIFN-gamma), a cytokine that shows promising clinical activity in epithelial ovarian cancer (EOC). METHODS: We examined EOC cell lines for the expression of arginase in an enzymatic assay and for transcripts of arginase I and II, inducible nitric oxide synthase (iNOS), and indoleamine 2,3-dioxygenase (IDO) by reverse transcription-polymerase chain reaction. The effects of rIFN-gamma on arginase activity and on tumor cell growth inhibition were determined by measuring [3H]thymidine uptake. RESULTS: Elevated arginase activity was detected in 5 of 8 tumor cell lines, and analysis at the transcriptional level showed that arginase II was involved but arginase I was not. rIFN-gamma reduced arginase activity in 3 EOC cell lines but increased activity in the 2008 cell line and its platinum-resistant subline, 2008.C13. iNOS transcripts were not detected in rIFN-gamma-treated or untreated cell lines. In contrast, IDO activity was induced or increased by rIFN-gamma. Suppression of arginase activity by rIFN-gamma in certain cell lines suggested that such inhibition might contribute to its antiproliferative effects. However, supplementation of the medium with polyamine pathway products did not interfere with the growth-inhibitory effects of rIFN-gamma EOC cells. CONCLUSIONS: Increased arginase activity, specifically identified with arginase II, is present in most of the tested EOC cell lines. rIFN-gamma inhibits or stimulates arginase activity in certain EOC cell lines, though the decrease in arginase activity does not appear to be associated with the in vitro antiproliferative activity of rIFN-gamma. Since cells within the stroma of EOC tissues could also contribute to arginine metabolism following treatment with rIFN-gamma or rIFN-gamma-inducers, it would be helpful to examine these effects in vivo.

Activation of DegP chaperone-protease via formation of large cage-like oligomers upon binding to substrate proteins.

Cells use molecular chaperones and proteases to implement the essential quality control mechanism of proteins. The DegP (HtrA) protein, essential for the survival of Escherichia coli cells at elevated temperatures with homologues found in almost all organisms uniquely has both functions. Here we report a mechanism for DegP to activate both functions via formation of large cage-like 12- and 24-mers after binding to substrate proteins. Cryo-electron microscopic and biochemical studies revealed that both oligomers are consistently assembled by blocks of DegP trimers, via pairwise PDZ1-PDZ2 interactions between neighboring trimers. Such interactions simultaneously eliminate the inhibitory effects of the PDZ2 domain. Additionally, both DegP oligomers were also observed in extracts of E. coli cells, strongly implicating their physiological importance.

DIRECT EFFECT OF MELATONIN UPON THE RELEASE OF GONADOTROPINS FROM THE SUPERFUSED PITUITARY GLAND OF THE MALE GOLDEN HAMSTER

The pineal gland is known to be light sensitive and to be involved in the seasonal reproduction of male golden hamster Mesocricetus auratus. In general, the pineal gland has been demonstrated to be inhibitory to the reproductive system of the male golden hamster. Melatonin is a pineal hormone which can mimic the action of the pineal gland upon the reproductive system. However, the actual site(s) of melatonin action in the hamster has not been demonstrated. In this study a direct effect of melatonin on the release of FSH and LH from superfused hamster pituitary glands was investigated.^ The superfused pituitary glands showed a stable in vitro basal release of FSH and LH for up to 10 hours. The superfused pituitaries demonstrated reproducible responses to repeated pulses of 10('-8) M LHRH, and a dose-dependent response to stimulation with different concentrations of LHRH.^ Melatonin inhibited the basal release of FSH and LH from superfused hamster pituitary glands. This effect of melatonin was specific and not a general indolamine or catecholamine effect.^ The superfused pituitaries had a diurnal differential responsiveness to physiological concentrations of melatonin with respect to FSH and LH release which were related to the light cycle used to maintain the experimental animals. A LD 14:10 photoperiod cycle was used with light on from 5 a.m. till 7 p.m.. With pituitary glands obtained at 8:30 a.m., the basal release of FSH exhibited an initial inhibition, a gradual rebound at approximately two hours after the beginning of melatonin superfusion, and a significant overshoot of FSH release after the cessation of infusion with melatonin (Morning Response). If the pituitary glands were obtained from hamsters which were sacrificed at 3:30 p.m., the release rate of FSH exhibited an inhibition during the entire period of melatonin infusion with a rebound effect appearing only after melatonin infusion was discontinued (Afternoon Response). There was no significant difference in the responsiveness of the pituitary gland to infusion with melatonin at either 8:30 a.m. or 3:30 p.m. with respect to LH release. Also, melatonin could not inhibit the gonadotropins response to continuous superfusion with 10('-9) M LHRH in pituitaries obtained at either 8:30 a.m. or 3:30 p.m., nor inhibit the stimulatory effect of pulsatile 10('-9) M LHRH. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI^

Characterization of recombinant class I MHC alloantigen action upon the survival of disparate heart allografts

Previous studies have led to the development of allochimeric class I MHC proteins as agents that effectively induce donor-specific transplantation tolerance in a rat system with or without additional immunosuppression. Within the α1-helical region of RT1.Au, an epitope that conferred immunologic tolerance was discovered. Studies presented herein were designed to test our central hypothesis that allochimeric proteins onfer tolerance in a mouse model. To test this hypothesis, portal vein (PV) injection of wild-type H2Kd and H2Dd proteins were produced in a bacterial expression system and found to specifically prolong the survival of BALB/c (H2d) heart allografts in C57BL/10 (H2b) recipients. Although a single PV injection of 50 μg α1–α 3 H2Kd alone was ineffective, 50 μg α1 –α3 alone slightly prolonged BALB/c heart allograft survivals. In contrast, the combination of 25 μg α1–α 3 H2Kd and 25 μg α1–α 3 H2Dd proteins prolonged BALB/c graft survivals to 20.2 ± 6.4 days (p < 0.004). The effect was donor-specific, since a combination of 25 μg α1–α3 H2Kd and 25 μg α1–α3 H2Dd proteins failed to affect survivals of third-party C3H (H2k k) heart allografts, namely 9.0 ± 0.0 days in treated versus 7.8 ± 0.5 days in untreated hosts. Thus, the combination of two H2K d and H2Dd proteins is more effective in prolonging allograft survival than a single protein produced in a bacterial expression system. A single PV injection (day 0) of 25 μg α1–α 2 H2Kd and 25 μg α1–α 2 H2Dd proteins to C57BL/10 mice prolonged the survival of BALB/c heart allografts to 22.4 ± 4.5 days. Within a WF to ACI rat heart allograft system, a single PV injection of 20 μg 70–77 u-RT1.Aa induced specific tolerance of allografts. This therapy could be combined with CsA to induce transplantation tolerance. However, combination of 70–77u-RT1.Aa with CTLA4Ig, rapamycin, or AG-490 effectively blocked the induction of transplantation tolerance. Tolerance generated by allochimeric protein could be adoptively transferred to naive recipients. Intragraft cytokine mRNA levels showed a bias towards a Th2-type phenotype. Additionally, studies of cytokine signaling and activation of transcription factors revealed a requirement that these pathways remain available for signaling in order for transplantation tolerance to occur. These studies suggest that the generation of regulatory cells are required for the induction of transplantation tolerance through the use of allochimeric proteins. ^

The impact of a child's unexpected hospitalization upon Taiwanese parents' situational anxiety

Background. The parents of a sick child likely experience situational anxiety due to their young child being unexpectedly hospitalized. The emotional upheaval may be great enough that their anxiety inhibits them in providing positive support to their hospitalized child. Because anxiety affects psychological distress as well as behavioral distress, identifying parental distress helps parents improving their coping mechanisms. ^ Purpose. The study compared situational anxiety levels between Taiwanese fathers and mothers and focused on differences between parental anxiety levels at the beginning of the child's unplanned hospitalization and at time of discharge. The study also identified factors related to the parents' distress and use of coping mechanisms. ^ Methods. A descriptive, comparative research design was used to determine the difference between the anxiety levels of 62 Taiwanese father-mother dyads during the situational crisis of their child's unexpected hospitalization. The Mandarin version (M) of Visual Analog Scale (VAS-M), State-Trait Anxiety Inventory (STAI-M), and the Index of Parent Participation/Hospitalized Child (IPP/HC-M) were used to differentiate maternal and paternal anxiety levels and identify factors related to the parents' distress. Questionnaires were completed by parents within 24-36 hours of the child's hospital admission and within 24 hours prior to discharge. A paired t-test, two sample t-test, and linear mixed regression model were used to test and support the study hypothesis. ^ Results. The findings reveal that the mothers' anxiety levels did not significantly differ from the fathers' anxiety level when their child had a sudden admission to the hospital. In particular, parental state anxiety levels did not decrease during the child's hospital stay and subsequent discharge. Moreover, anxiety levels did not differ between parents regardless of whether the child's disease was acute or chronic. The most effective factor related to parental situational anxiety was parental perception of the severity of the child's illness. ^ Conclusions. Parental anxiety was found to be significantly related to changes in their perception of the severity of their child's illness. However, the study was not able to illustrate how parental involvement in the child's hospital care was related to parental perception of the severity of their child's illness. Future studies, using a qualitative approach to gamer more information as to what variables influence parental anxiety during a situational crisis, may provide a richer database from which to modify key variables as well as the instruments used to improve the quality of the data obtained. ^

Nurse likelihood to report a pediatric medication error: Examination of the "pre-reporting" period

Each year, hospitalized patients experience 1.5 million preventable injuries from medication errors and hospitals incur an additional $3.5 billion in cost (Aspden, Wolcott, Bootman, & Cronenwatt; (2007). It is believed that error reporting is one way to learn about factors contributing to medication errors. And yet, an estimated 50% of medication errors go unreported. This period of medication error pre-reporting, with few exceptions, is underexplored. The literature focuses on error prevention and management, but lacks a description of the period of introspection and inner struggle over whether to report an error and resulting likelihood to report. Reporting makes a nurse vulnerable to reprimand, legal liability, and even threat to licensure. For some nurses this state may invoke a disparity between a person‘s belief about him or herself as a healer and the undeniable fact of the error.^ This study explored the medication error reporting experience. Its purpose was to inform nurses, educators, organizational leaders, and policy-makers about the medication error pre-reporting period, and to contribute to a framework for further investigation. From a better understanding of factors that contribute to or detract from the likelihood of an individual to report an error, interventions can be identified to help the nurse come to a psychologically healthy resolution and help increase reporting of error in order to learn from error and reduce the possibility of future similar error.^ The research question was: "What factors contribute to a nurse's likelihood to report an error?" The specific aims of the study were to: (1) describe participant nurses' perceptions of medication error reporting; (2) describe participant explanations of the emotional, cognitive, and physical reactions to making a medication error; (3) identify pre-reporting conditions that make it less likely for a nurse to report a medication error; and (4) identify pre-reporting conditions that make it more likely for a nurse to report a medication error.^ A qualitative research study was conducted to explore the medication error experience and in particular the pre-reporting period from the perspective of the nurse. A total of 54 registered nurses from a large private free-standing not-for-profit children's hospital in the southwestern United States participated in group interviews. The results describe the experience of the nurse as well as the physical, emotional, and cognitive responses to the realization of the commission of a medication error. The results also reveal factors that make it more and less likely to report a medication error.^ It is clear from this study that upon realization that he or she has made a medication error, a nurse's foremost concern is for the safety of the patient. Fear was also described by each group of nurses. The nurses described a fear of several things including physician reaction, manager reaction, peer reaction, as well as family reaction and possible lack of trust as a result. Another universal response was the description of a struggle with guilt, shame, imperfection, blaming oneself, and questioning one's competence.^