Exploring the Knowledge Structures of Korean and International Nursing Research on Premature Infants Using Text Network Analysis.

This study aimed to identify the knowledge structures of Korean and international nursing studies on premature infants using text network analysis, which represents a text as a network graph that describes how keywords are linked. This network graph refers to a knowledge structure. International and Korean journal databases were searched to extract nursing studies regarding premature infants published in academic journals from 1998 to 2020. Abstracts from the selected studies were analyzed using the following four steps: word extraction and refinement, keyword extraction, co-occurrence matrix generation, and text network visualization. The results demonstrated that 182 Korean and 2502 international studies were published. The common keywords of Korean and international studies were "kangaroo mother care," "stress," and "child." The keywords of the international studies had more branches linking to other keywords than those of the Korean studies. Thus, the knowledge structure of international studies included diverse concepts. These findings will serve as important guidance for future research worldwide. Furthermore, studies to develop a more comprehensive knowledge structure of international research on premature infants are needed. The knowledge structure of Korean studies mainly included concepts related to mothers. Korean studies regarding hospitalized premature infants and communication with parents need to be conducted.

Identifying Latent Topics and Trends in Premature Infant-Related Nursing Studies Using a Latent Dirichlet Allocation Method.

This study aimed to identify topics and within-topic core keywords in premature infant-related nursing studies published in Korean and international academic journals using topic modeling and to compare and analyze the trends in Korean and international studies. Journal databases were searched to extract nursing studies involving premature infants from 1998 to 2020. Journal databases included MEDLINE, Web of Science, CINAHL, and EMBASE for international studies and DBpia, the National Digital Science Library, the Korea Citation Index, and the Research Information Sharing Service for Korean studies. Abstracts from the selected 182 Korean and 2502 international studies were analyzed using NetMiner4.4.3e. In results, four similar topics (Korean vs international) were "pain intervention" versus "pain management"; "breast feeding practice" versus "breast feeding"; "kangaroo mother care"; and "parental stress" versus "stress & depression." Two topics that appeared only in the international studies were "infection management" and "oral feeding & respiratory care." Overall, the international studies dealt with diverse topics directly associated with premature. Korean studies mainly dealt with topics related to mothers of premature infants, whereas studies related to premature infants were insufficient. Nursing research in Korea needs to be expanded to research topics addressing premature infants.

Analysis of online parenting community posts on expanded newborn screening for metabolic disorders using topic modeling: a quantitative content analysis.

PURPOSE: As more newborns have received expanded newborn screening (NBS) for metabolic disorders, the overall number of false-positive results has increased. The purpose of this study was to explore the psychological impacts experienced by mothers related to the NBS process. METHODS: An online parenting community in Korea was selected, and questions regarding NBS were collected using web crawling for the period from October 2018 to August 2021. In total, 634 posts were analyzed. The collected unstructured text data were preprocessed, and keyword analysis, topic modeling, and visualization were performed. RESULTS: Of 1,057 words extracted from posts, the top keyword based on 'term frequency-inverse document frequency' values was "hypothyroidism," followed by "discharge," "close examination," "thyroid-stimulating hormone levels," and "jaundice." The top keyword based on the simple frequency of appearance was "XXX hospital," followed by "close examination," "discharge," "breastfeeding," "hypothyroidism," and "professor." As a result of LDA topic modeling, posts related to inborn errors of metabolism (IEMs) were classified into four main themes: "confirmatory tests of IEMs," "mother and newborn with thyroid function problems," "retests of IEMs," and "feeding related to IEMs." Mothers experienced substantial frustration, stress, and anxiety when they received positive NBS results. CONCLUSION: The online parenting community played an important role in acquiring and sharing information, as well as psychological support related to NBS in newborn mothers. Nurses can use this study's findings to develop timely and evidence-based information for parents whose children receive positive NBS results to reduce the negative psychological impact.

Nurses' Electronic Medical Record Workarounds in a Tertiary Teaching Hospital.

The objective of this study was to identify nurses' workarounds related to the use of electronic medical records in a tertiary teaching hospital. A total of 106 nurses (84.8%) using the electronic medical records completed 10-item questionnaires scored on a Likert scale and five open-ended questions with written responses. The numerical data were analyzed by descriptive statistics, and the written descriptions were categorized by meaning. The mean of the scored items ranged from 3.29 to 3.74. Approximately 38% to 50% of the participants reported (very) frequent workflow delays due to the use of the electronic medical records, and 46% to 64% reported (very) frequently using workarounds. Twenty-nine workarounds of the electronic medical records were due to electronic documentation, difficulty accessing the electronic medical records, medication administration, covering physician responsibilities, electronic communication with the physicians, respondents and physicians not skilled in using the electronic medical records, and connection failures between devices or machines and the electronic medical records. Although none of these identified workarounds were intended to be harmful, and certain workarounds were efficient for patient care and workflow, whether patient safety can be jeopardized by workarounds should be considered. This study contributes to the understanding of why and how workarounds occur in the hospital. It will be useful for achieving greater alignment between work contexts and the electronic medical record in the future.

Implementation of an Electronic Nursing Record for Nursing Documentation and Communication of Patient Care Information in a Tertiary Teaching Hospital.

Despite the fact that implementing an electronic nursing record has become an everyday event for nurses, little is known about which type of documentation used in an electronic nursing record is better for nursing practice. The aim of this exploratory study was to identify the most suitable type of electronic nursing documentation that nurses used to record care and communicate with clinicians. Participants consisted of 118 nurses and 12 physicians. Researchers developed a self-report questionnaire of 17 items about electronic nursing record use for documentation and communication of patient care information. Data were analyzed using descriptive statistics to calculate frequencies and percentages. The χ2 test was used to identify differences in responses by demographic and clinical characteristics of participants. Bar charts were used to identify response patterns. Results showed that semistructured nursing documentation was the most preferred for care documentation and communication of patient information. Nurses did not always use the electronic nursing record to communicate patient care-related information. This study adds empirical knowledge about which type of documentation used in the electronic nursing record works well, what improvement is needed for better nursing practice, and whether the electronic nursing record has been used for communication.

Conditionally reprogrammed normal and primary tumor prostate epithelial cells: a novel patient-derived cell model for studies of human prostate cancer.

Our previous study demonstrated that conditional reprogramming (CR) allows the establishment of patient-derived normal and tumor epithelial cell cultures from a variety of tissue types including breast, lung, colon and prostate. Using CR, we have established matched normal and tumor cultures, GUMC-29 and GUMC-30 respectively, from a patient's prostatectomy specimen. These CR cells proliferate indefinitely in vitro and retain stable karyotypes. Most importantly, only tumor-derived CR cells (GUMC-30) produced tumors in xenografted SCID mice, demonstrating maintenance of the critical tumor phenotype. Characterization of cells with DNA fingerprinting demonstrated identical patterns in normal and tumor CR cells as well as in xenografted tumors. By flow cytometry, both normal and tumor CR cells expressed basal, luminal, and stem cell markers, with the majority of the normal and tumor CR cells expressing prostate basal cell markers, CD44 and Trop2, as well as luminal marker, CD13, suggesting a transit-amplifying phenotype. Consistent with this phenotype, real time RT-PCR analyses demonstrated that CR cells predominantly expressed high levels of basal cell markers (KRT5, KRT14 and p63), and low levels of luminal markers. When the CR tumor cells were injected into SCID mice, the expression of luminal markers (AR, NKX3.1) increased significantly, while basal cell markers dramatically decreased. These data suggest that CR cells maintain high levels of proliferation and low levels of differentiation in the presence of feeder cells and ROCK inhibitor, but undergo differentiation once injected into SCID mice. Genomic analyses, including SNP and INDEL, identified genes mutated in tumor cells, including components of apoptosis, cell attachment, and hypoxia pathways. The use of matched patient-derived cells provides a unique in vitro model for studies of early prostate cancer.

Oxidative modification of ferritin induced by methylglyoxal.

Methylglyoxal (MG) was identified as an intermediate in non-enzymatic glycation and increased levels were reported in patients with diabetes. In this study, we evaluated the effects of MG on the modification of ferritin. When ferritin was incubated with MG, covalent crosslinking of the protein increased in a time- and MG dose-dependent manner. Reactive oxygen species (ROS) scavengers, N-acetyl-(L)-cysteine and thiourea suppressed the MG-mediated ferritin modification. The formation of dityrosine was observed in MG-mediated ferritin aggregates and ROS scavengers inhibited the formation of dityrosine. During the reaction between ferritin and MG, the generation of ROS was increased as a function of incubation time. These results suggest that ROS may play a role in the modification of ferritin by MG. The reaction between ferritin and MG led to the release of iron ions from the protein. Ferritin exposure to MG resulted in a loss of arginine, histidine and lysine residues. It was assumed that oxidative damage to ferritin caused by MG may induce an increase in the iron content in cells, which is deleterious to cells. This mechanism, in part, may provide an explanation or the deterioration of organs under diabetic conditions.

Oxidative modification of ferritin induced by hydrogen peroxide.

Excess free iron generates oxidative stress that may contribute to the pathogenesis of various causes of neurodegenerative diseases. In this study, we assessed the modification of ferritin induced by H(2)O(2). When ferritin was incubated with H(2)O(2), the degradation of ferritin L-chain increased with the H(2)O(2) concentration whereas ferritin H-chain was remained. Free radical scavengers, azide, thiourea, and N-acetyl-(L)-cysteine suppressed the H(2)O(2)-mediated ferritin modification. The iron specific chelator, deferoxamine, effectively prevented H(2)O(2)-mediated ferritin degradation in modified ferritin. The release of iron ions from ferritin was increased in H(2)O(2) concentration-dependent manner. The present results suggest that free radicals may play a role in the modification and iron releasing of ferritin by H(2)O(2). It is assumed that oxidative damage of ferritin by H(2)O(2) may induce the increase of iron content in cells and subsequently lead to the deleterious condition.

Vitamin C increases the apoptosis via up-regulation p53 during cisplatin treatment in human colon cancer cells.

Vitamin C (VC) is an important antioxidant and enzyme co-factor that works by stimulating the immune system and protecting against infections. It is well known that melanoma cells are more susceptible to VC than any other tumor cells. However, the role of VC in the treatment of colon cancer has not been studied. Cisplatin (CDDP) is a DNA damaging agent and is widely used for treating cancer, while the role of p53 in CDDP-induced cell death has been stressed. Using cell growth assays, morphological methods, Western blotting, flow cytometry, and DNA fragmentation analysis, we measured the expression of p53 level involved in the effect of VC on CDDP-induced apoptosis of HCT116, a human colon cancer cell line. CDDP plus VC treatment resulted in significantly increased apoptosis along with upregulation of p53 compared to untreated cells and/or CDDP-treated cells. These results suggest that VC enhanced CDDP sensitivity and apoptosis via upregulation of p53.

Reaction of ferritin with hydrogen peroxide induces lipid peroxidation.

Lipid peroxidation is known to be an important factor in the pathologies of many diseases associated with oxidative stress. We assessed the lipid peroxidation induced by the reaction of ferritin with H2O2. When linoleic acid micelles or phosphatidyl choline liposomes were incubated with ferritin and H2O2, lipid peroxidation increased in the presence of ferritin and H2O2 in a concentration-dependent manner. The hydroxyl radical scavengers, azide and thiourea, prevented lipid peroxidation induced by the ferritin/H2O2 system. The iron specific chelator desferoxamine also prevented ferritin/H2O2 systemmediated lipid peroxidation. These results demonstrate the possible role of iron in ferritin/H2O2 system-mediated lipid peroxidation. Carnosine is involved in many cellular defense processes, including free radical detoxification. In this study, carnosine, homocarnosine, and anserine were shown to significantly prevent ferritin/H2O2 system-mediated lipid peroxidation and also inhibited the free radical-generation activity of ferritin. These results indicated that carnosine and related compounds may prevent ferritin/H2O2 system-mediated lipid peroxidation via free radical scavenging.

Intermittent hypoxia activates peptidylglycine alpha-amidating monooxygenase in rat brain stem via reactive oxygen species-mediated proteolytic processing.

Intermittent hypoxia (IH) associated with sleep apneas leads to cardiorespiratory abnormalities that may involve altered neuropeptide signaling. The effects of IH on neuropeptide synthesis have not been investigated. Peptidylglycine alpha-amidating monooxygenase (PAM; EC 1.14.17.3) catalyzes the alpha-amidation of neuropeptides, which confers biological activity to a large number of neuropeptides. PAM consists of O(2)-sensitive peptidylglycine alpha-hydroxylating monooxygenase (PHM) and peptidyl-alpha-hydroxyglycine alpha-amidating lyase (PAL) activities. Here, we examined whether IH alters neuropeptide synthesis by affecting PAM activity and, if so, by what mechanisms. Experiments were performed on the brain stem of adult male rats exposed to IH (5% O(2) for 15 s followed by 21% O(2) for 5 min; 8 h/day for up to 10 days) or continuous hypoxia (0.4 atm for 10 days). Analysis of brain stem extracts showed that IH, but not continuous hypoxia, increased PHM, but not PAL, activity of PAM and that the increase of PHM activity was associated with a concomitant elevation in the levels of alpha-amidated forms of substance P and neuropeptide Y. IH increased the relative abundance of 42- and 35-kDa forms of PHM ( approximately 1.6- and 2.7-fold, respectively), suggesting enhanced proteolytic processing of PHM, which appears to be mediated by an IH-induced increase of endoprotease activity. Kinetic analysis showed that IH increases V(max) but has no effect on K(m). IH increased generation of reactive oxygen species in the brain stem, and systemic administration of antioxidant prevented IH-evoked increases of PHM activity, proteolytic processing of PHM, endoprotease activity, and elevations in substance P and neuropeptide Y amide levels. Taken together, these results demonstrate that IH activates PHM in rat brain stem via reactive oxygen species-dependent posttranslational proteolytic processing and further suggest that PAM activation may contribute to IH-mediated peptidergic neurotransmission in rat brain stem.

Activation of tyrosine hydroxylase by intermittent hypoxia: involvement of serine phosphorylation.

Regulation of tyrosine hydroxylase (TH) by intermittent hypoxia (IH) was investigated in rat pheochromocytoma 12 (PC-12) cells by exposing them to alternating cycles of hypoxia (1% O2, 15 s) and normoxia (21% O2, 3 min) for up to 60 cycles; controls were exposed to normoxia for a similar duration. IH exposure increased dopamine content and TH activity by approximately 42 and approximately 56%, respectively. Immunoblot analysis revealed that comparable levels of TH protein were expressed in normoxic and IH cells. Removal of TH-bound catecholamines and in vitro phosphorylation of TH in cell-free extracts by the catalytic subunit of protein kinase A (PKA) increased TH activity in normoxic but not in IH cells, suggesting possible induction of TH phosphorylation and removal of endogenous inhibition of TH by IH. To assess the role of serine phosphorylation in IH-induced TH activation, TH immunoprecipitates and extracts derived from normoxic and IH cells were probed with anti-phosphoserine and anti-phospho-TH (Ser-40) antibody, respectively. Compared with normoxic cells, total serine and Ser-40-specific phosphorylation of TH were increased in IH cells. IH-induced activation of TH and the increase in total serine and Ser-40-specific phosphorylation of TH were inhibited by Ca2+/calmodulin-dependent protein kinase (CaMK) and PKA-specific inhibitors but not by inhibitors of the extracellular signal-regulated protein kinase pathway, suggesting that IH activates TH in PC-12 cells via phosphorylation of serine residues including Ser-40, in part, by CaMK and PKA. Our results also suggest that IH-induced phosphorylation of TH facilitates the removal of endogenous inhibition of TH, leading to increased synthesis of dopamine.