Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 20
Filter
Add more filters










Publication year range
1.
Soc Psychol Educ ; : 1-19, 2023 Apr 04.
Article in English | MEDLINE | ID: mdl-37362052

ABSTRACT

Previous literature has demonstrated that peer support is instrumental for the promotion of adaptive academic and mental health outcomes; however, limited research has examined prospective directional associations between peer support and adjustment within college settings. The purpose of this study was to investigate the longitudinal associations between peer support, academic competence, and anxiety among U.S. college students. U.S. students from a diverse 4-year university (N = 251, 75% women, 24% men, and < 1% a different gender) reported on peer support, academic competence, and anxiety using validated questionnaires at two time points (Fall term of sophomore year and Spring term of senior year). Results showed that peer support was positively associated with academic competence over time but was not significantly related to future anxiety. Academic competence did not significantly predict peer support or anxiety over time, but anxiety was associated with lower future academic competence. These findings offer insight into how types of social relationships link with academic motivation and anxiety over time within educational settings.

2.
Cureus ; 15(5): e38453, 2023 May.
Article in English | MEDLINE | ID: mdl-37273297

ABSTRACT

Merkel cell carcinoma (MCC) is a rare but highly aggressive skin cancer that carries a high rate of lymph node involvement and death. The National Comprehensive Cancer Network recommends sentinel lymph node (SLN) biopsy for the staging of the disease. Scintigraphy using radioactive isotopes (RI) such as technetium 99m (Tc99) remains the gold standard for the detection of SLNs, however, recently indocyanine green (ICG) fluorescence imaging has been used to aid in the detection of SLNs.We present the case of a patient who presented with MCC of the face and two SLNs successfully identified with ICG fluorescence despite the fact that they were not detected by intraoperative scintigraphy using Tc99. The use of ICG fluorescence imaging in MCC is safe and improves the ability to detect SLNs when combined with RI.

3.
Dev Psychol ; 58(5): 950-962, 2022 May.
Article in English | MEDLINE | ID: mdl-35311307

ABSTRACT

This study examined longitudinal associations between early adolescents' school friendship stability, instability, and network size and their perceived social adjustment. The final sample consisted of 430 early adolescents residing in seven Midwestern schools (52% female, 47% Black, 42% White, 5% Hispanic or Latinx, and 6% Other). School friendship stability, instability, and network size were assessed via students' peer nominations of their same-grade friendships collected midway through their 7th and 8th grade years. Students also self-reported on several measures of social adjustment (their social satisfaction, social confidence, and school belonging). Results indicated having new friendships and having a larger friendship network at school were each more predictive of early adolescents' perceived social adjustment than was having maintained friendships or a consistent friend group within this context. However, school friendship stability consistently predicted greater perceived school belonging, whereas having a primarily new friend group and/or having lost more or most of a prior friend group predicted lower levels of this perception. Having lost school friendships was not predictive of early adolescents' social adjustment except when losses composed a significant proportion of their school friendship network (i.e., they had lost more or most of their school friendships from the year before). These findings provide valuable insights about peer friendship dynamics and social adjustment during a life stage critical to social development. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Subject(s)
Friends , Social Adjustment , Adolescent , Female , Humans , Interpersonal Relations , Male , Peer Group , Schools , Students
4.
Dev Psychol ; 57(6): 991-999, 2021 Jun.
Article in English | MEDLINE | ID: mdl-34424015

ABSTRACT

Expecting discrimination in one's future occupation is known to have negative implications for adolescents' career pathways. However, little is known about how such discriminatory expectations emerge. The current contentious sociopolitical climate toward immigrants, especially those of Latinx heritage, has contributed to heightened discrimination against adolescents in this group. The present study examined how experiences of discrimination over time relate to youths' expectations of future occupational barriers among 148 Latinx adolescents at 3 annual waves (82% U.S.-born; 53% female; Mage = 13.54 at Wave 1). Results suggest that Latinx youth report increasing exposure to ethnic-racial discrimination and objectification as a perceived foreigner over time. Moreover, as Latinx youth perceived more ethnic-racial discrimination and foreigner objectification over the course of adolescence they increasingly expected to face racial and ethnic barriers in their future occupations. Implications of these findings for an increasing Latinx youth and working-age population in the United States are discussed. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Subject(s)
Racism , Adolescent , Ethnicity , Female , Hispanic or Latino , Humans , Male , Racial Groups , Social Identification , United States
5.
Cureus ; 13(5): e15248, 2021 May 26.
Article in English | MEDLINE | ID: mdl-34188987

ABSTRACT

Indocyanine green (ICG) angiography is a real-time imaging modality that can be used to assess intraoperative tissue perfusion. ICG dye has proven to be feasible, safe, and cost-effective, especially for muscle flaps during complex reconstructions. To our knowledge, we discuss the first use of ICG angiography for the real-time assessment of a tongue flap following left lateral hemiglossectomy. ICG angiography showed excellent perfusion of the tongue and tongue flap, which subsequently led to an uncomplicated postoperative recovery.

6.
Cureus ; 13(3): e13970, 2021 Mar 18.
Article in English | MEDLINE | ID: mdl-33884231

ABSTRACT

Indocyanine green (ICG) angiography is a procedure that uses a fluorescent dye for a variety of medical diagnostics, including the real-time examination of blood flow in tissue. Herein, we report a case in which ICG angiography was used to assess the viability of a sternocleidomastoid (SCM) muscle flap during post-parotidectomy facial reconstruction. To our knowledge, this is the first report documenting the intraoperative use of ICG for the evaluation of SCM flap perfusion. ICG angiography may prove beneficial for cases involving complex reconstructions and suspected organ hypoperfusion.

7.
J Biol Chem ; 296: 100501, 2021.
Article in English | MEDLINE | ID: mdl-33667548

ABSTRACT

Nitrogenase is the only enzyme capable of catalyzing nitrogen fixation, the reduction of dinitrogen gas (N2) to ammonia (NH3). Nitrogenase is tightly inhibited by the environmental gas carbon monoxide (CO). Nitrogen-fixing bacteria rely on the protein CowN to grow in the presence of CO. However, the mechanism by which CowN operates is unknown. Here, we present the biochemical characterization of CowN and examine how CowN protects nitrogenase from CO. We determine that CowN interacts directly with nitrogenase and that CowN protection observes hyperbolic kinetics with respect to CowN concentration. At a CO concentration of 0.001 atm, CowN restores nearly full nitrogenase activity. Our results further indicate that CowN's protection mechanism involves decreasing the binding affinity of CO to nitrogenase's active site approximately tenfold without interrupting substrate turnover. Taken together, our work suggests CowN is an important auxiliary protein in nitrogen fixation that engenders CO tolerance to nitrogenase.


Subject(s)
Bacterial Proteins/metabolism , Carbon Monoxide/pharmacology , Gluconacetobacter/metabolism , Nitrogen Fixation , Nitrogen/metabolism , Nitrogenase/metabolism , Bacterial Proteins/chemistry , Catalysis , Gluconacetobacter/drug effects , Gluconacetobacter/genetics , Kinetics , Models, Molecular , Nitrogenase/chemistry , Oxidation-Reduction , Protein Interaction Domains and Motifs
8.
Dev Psychol ; 56(8): 1458-1474, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32790445

ABSTRACT

The purpose of this study is to examine how parents' documentation status informs their ethnic-racial socialization (ERS) practices and the subsequent implications for Latinx youths' psychological adjustment. The mixed-methods approach combined convergent and exploratory sequential designs to explore the breadth and depth of Latinx parents' messages to their children regarding race and ethnicity. Qualitative data were used to generate hypotheses that were tested quantitatively. Analysis of interviews revealed parents' concerns with obeying the law, avoiding interaction with others, teaching children how to deal with discrimination, the importance of transmitting their culture, and concerns for their children's ever-present fear and stress. Path analysis showed that undocumented parents utilized more cultural socialization and promotion of mistrust messages than their documented counterparts. More promotion of mistrust, in turn, was associated with higher levels of adolescent depressive symptoms. Given the current sociopolitical climate and ethnic-racial tensions in the United States, it is imperative to gain a more comprehensive understanding of the nuanced ERS practices Latinx families employ to both cope with and respond to this situation. (PsycInfo Database Record (c) 2020 APA, all rights reserved).


Subject(s)
Emigrants and Immigrants/legislation & jurisprudence , Emigrants and Immigrants/psychology , Emotional Adjustment , Ethnicity/psychology , Hispanic or Latino/psychology , Parents/psychology , Psychosocial Functioning , Socialization , Adolescent , Child , Female , Humans , Male , United States
9.
J Youth Adolesc ; 49(4): 895-906, 2020 Apr.
Article in English | MEDLINE | ID: mdl-31587174

ABSTRACT

Family socialization of one's ethnic culture is essential for ethnic identity development among Latinx adolescents. However, less is known about how the likely changes in family interaction that transpire during adolescence may impact this socialization process. A three-year longitudinal study of 148 Latinx adolescents (ages 13-14; 53% females) examined how changes in youth's family ethnic socialization experiences and sense of family cohesion were related to two dimensions of their ethnic identity development (i.e., exploration and resolution). Youth's family ethnic socialization experiences and sense of family cohesion remained stable, while their exploration and resolution increased across three years. More ethnic socialization experiences at Wave 1 predicted higher initial levels and stability of ethnic identity exploration over time. However, more ethnic socialization at Wave 1 predicted higher initial levels of resolution and predicted less resolution development as youth progressed through adolescence. Among youth who perceived less ethnic socialization, a greater sense of family cohesion was associated with more initial exploration; this compensatory effect was only present at Wave 1. These results illustrate how distinct aspects of the family context uniquely and interactively inform ethnic identity exploration and resolution development.


Subject(s)
Cultural Characteristics , Hispanic or Latino/psychology , Social Identification , Socialization , Adolescent , Family Relations/psychology , Female , Humans , Longitudinal Studies , Male , Psychology, Adolescent , Socioeconomic Factors
10.
Child Dev ; 90(6): 1898-1916, 2019 11.
Article in English | MEDLINE | ID: mdl-29785741

ABSTRACT

This study offers new insights into the power of peer networks for shaping intergroup relations in a diverse school. Data were drawn from a longitudinal study of sixth-eighth graders (N = 524; MageT1  = 11.87; 48% girls; 9% Asian American/Pacific Islander, 28% African American, 13% Latino, 1% Native American, 31% White, 5% Other, and 11% Multiracial) in the Midwestern United States. Students with more positive intergroup contact attitudes (ICA) were most likely to be friends with similarly minded students. Students with more positive ICA were less likely to select friends of the same race/ethnicity than those with less positive ICA. Finally, students' ICA became more similar to their friends' ICA over time. Results implicate school-level norms and contagion in students' ICA.


Subject(s)
Attitude , Ethnicity , Friends , Group Processes , Peer Group , Students , Adolescent , Child , Female , Humans , Longitudinal Studies , Male , Midwestern United States , Schools
11.
Front Microbiol ; 9: 2671, 2018.
Article in English | MEDLINE | ID: mdl-30487779

ABSTRACT

Bacterial manganese (Mn) oxidation is catalyzed by a diverse group of microbes and can affect the fate of other elements in the environment. Yet, we understand little about the enzymes that catalyze this reaction. The Mn oxidizing protein MopA, from Erythrobacter sp. strain SD-21, is a heme peroxidase capable of Mn(II) oxidation. Unlike Mn oxidizing multicopper oxidase enzymes, an understanding of MopA is very limited. Sequence analysis indicates that MopA contains an N-terminal heme peroxidase domain and a C-terminal calcium binding domain. Heterologous expression and nickel affinity chromatography purification of the N-terminal peroxidase domain (MopA-hp) from Erythrobacter sp. strain SD-21 led to partial purification. MopA-hp is a heme binding protein that requires heme, NAD+, and calcium (Ca2+) for activity. Mn oxidation is also stimulated by the presence of pyrroloquinoline quinone. MopA-hp has a K M for Mn(II) of 154 ± 46 µM and k cat = 1.6 min-1. Although oxygen requiring MopA-hp is homologous to peroxidases based on sequence, addition of hydrogen peroxide and hydrogen peroxide scavengers had little effect on Mn oxidation, suggesting this is not the oxidizing agent. These studies provide insight into the mechanism by which MopA oxidizes Mn.

12.
Environ Sci Pollut Res Int ; 25(24): 23373-23382, 2018 Aug.
Article in English | MEDLINE | ID: mdl-27146537

ABSTRACT

Organic market gardening is often promoted by urban municipalities as a way to resource part of the food supply, creating new social links and protecting groundwater resources. The agronomical and environmental performance of six commercial organic market gardening farms supplying vegetables in Paris were evaluated and compared with other vegetable production systems. When expressed in terms of protein production, the yield of these systems appears rather low compared with the productive capacity of open-field organic cropping systems where vegetable production is inserted into rotation with other crops. Moreover, the requirement of producing infiltrated water meeting the drinking water standards seriously limits the allowable rate of fertilisation, thus limiting production. The data reported herein show that to supply the amount of vegetables required by the Paris agglomeration (12 million inhabitants) only by organic market gardening, 160,000-205,000 ha, i.e. 28-36 % of the agricultural area of the surrounding Ile-de-France region, would be required. We conclude that organic market gardening is only one of several other farming systems which can contribute to a re-localised supply of vegetables to large cities.


Subject(s)
Food Supply/statistics & numerical data , Organic Agriculture/statistics & numerical data , Vegetables , Agricultural Irrigation , Farms/statistics & numerical data , Food Supply/methods , France , Paris
13.
Child Dev ; 88(3): 710-724, 2017 05.
Article in English | MEDLINE | ID: mdl-28322437

ABSTRACT

The current study examined how adolescents' ethnic-racial identity (ERI) informed the demographic diversity of their friendship network (Goal 1) and the extent of similarity between adolescents' and their friends' ERI (Goal 2). Participants were sixth and seventh grade students (N = 353; Mage  = 11.88, SD = .73; 50% girls; 29% African American, 31% White, 13% Latino) in the Midwestern U.S. Results from longitudinal cross-lagged models (Goal 1) indicated that having more diverse friendships at T2 was associated with greater T3 ERI exploration among all youth. In addition, boys who reported higher ERI resolution at T1 had more diverse friendships at T2. Furthermore, findings from longitudinal social network analyses (SNA; Goal 2) suggested that influence drove similarity between adolescents and their friends in ERI exploration and resolution.


Subject(s)
Adolescent Behavior/ethnology , Asian , Black or African American/ethnology , Friends/ethnology , Hispanic or Latino , Social Identification , White People/ethnology , Adolescent , Female , Humans , Male , Midwestern United States/ethnology , Peer Group
14.
Case Rep Emerg Med ; 2015: 275497, 2015.
Article in English | MEDLINE | ID: mdl-26090241

ABSTRACT

The hemodynamic compromise caused by a large aspirated food particle in the airway can become the focus of medical attention and a distraction from rare but fatal Heimlich maneuver related injuries after an incident of food aspiration. We herein present a case of an 84-year-old man who was brought to the emergency department after an episode of choking at a restaurant followed by several failed Heimlich maneuver attempts. Despite relieving the airway obstruction by extracting a large piece of steak from the airway, the patient remained hypotensive and required continued hemodynamic support. Repeated laboratory tests within 24 hrs of aspiration showed a significant decline in the hemoglobin level. A computed tomography (CT) scan of the abdomen and pelvis showed a lacerated liver with a large subcapsular hematoma draining into the pelvis. Conclusion. Hepatic rupture is a rare complication of Heimlich maneuver; this paper represents the second case report in the literature. It emphasizes the necessity of early identification and surveillance of fatal Heimlich maneuver complications in a high risk population.

15.
Appl Environ Microbiol ; 80(21): 6837-42, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25172859

ABSTRACT

The manganese (Mn)-oxidizing protein (MopA) from Erythrobacter sp. strain SD21 is part of a unique enzymatic family that is capable of oxidizing soluble Mn(II). This enzyme contains two domains, an animal heme peroxidase domain, which contains the catalytic site, followed by a C-terminal calcium binding domain. Different from the bacterial Mn-oxidizing multicopper oxidase enzymes, little is known about MopA. To gain a better understanding of MopA and its role in Mn(II) oxidation, the 238-kDa full-length protein and a 105-kDa truncated protein containing only the animal heme peroxidase domain were cloned and heterologously expressed in Escherichia coli. Despite having sequence similarity to a peroxidase, hydrogen peroxide did not stimulate activity, nor was activity significantly decreased in the presence of catalase. Both pyrroloquinoline quinone (PQQ) and hemin increased Mn-oxidizing activity, and calcium was required. The Km for Mn(II) of the full-length protein in cell extract was similar to that of the natively expressed protein, but the Km value for the truncated protein in cell extract was approximately 6-fold higher than that of the full-length protein, suggesting that the calcium binding domain may aid in binding Mn(II). Characterization of the heterologously expressed MopA has provided additional insight into the mechanism of bacterial Mn(II) oxidation, which will aid in understanding the role of MopA and Mn oxidation in bioremediation and biogeochemical cycling.


Subject(s)
Bacterial Proteins/metabolism , Manganese/metabolism , Sphingomonadaceae/enzymology , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Calcium/metabolism , Cloning, Molecular , Coenzymes/metabolism , Enzyme Activators , Escherichia coli/genetics , Escherichia coli/metabolism , Gene Expression , Hemin/metabolism , Kinetics , Molecular Weight , Oxidation-Reduction , PQQ Cofactor/metabolism , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism
16.
J Trauma Acute Care Surg ; 76(1): 134-9, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24368368

ABSTRACT

BACKGROUND: We hypothesized that patients with pelvic fractures and hemorrhage admitted during daytime hours were undergoing interventional radiology (IR) earlier than those admitted at night and on weekends, thereby establishing two standards of time to hemorrhage control. METHODS: The trauma registry (January 2008 to December 2011) was reviewed for patients admitted with pelvic fractures, hemorrhagic shock, and transfusion of at least 1 U of blood. The control group (DAY) was admitted from 7:30 AM to 5:30 PM Monday to Friday, while the study group (after hours [AHR]) was admitted from 5:30 PM to 7:30 AM, on weekends or holidays. RESULTS: A total of 191 patients met the criteria (45 DAY, 146 AHR); 103 died less than 24 hours and without undergoing IR (29% DAY group vs. 62% AHR, p < 0.001). Sixteen patients (all in AHR group) died while awaiting IR (p = 0.032). Eighty-eight patients (32 DAY, 56 AHR) survived to receive IR. Among these, the AHR group were younger (median, 30 years vs. 54 years; p = 0.007), more tachycardic (median pulse, 119 beats/min vs. 90 beats/min; p = 0.001), and had more profound shock (median base, -10 vs. -6; p = 0.006) on arrival. Time from admission to IR (median, 301 minutes vs. 193 minutes; p < 0.001) and computed tomographic scan to IR (176 minutes vs. 87 minutes, p = 0.011) were longer in the AHR group. There was no difference in the 30-day mortality by univariate analysis. However, after controlling for age, arrival physiology, injury severity, and degree of shock, the AHR group had a 94% increased risk of mortality. CONCLUSION: The current study demonstrated that patients admitted at night and on weekends have a significant increase in time to angioembolization compared with those arriving during the daytime and during the week. Multivariate regression noted that AHR management was associated with an almost 100% increase in mortality. While this is a single-center study and retrospective in nature, it suggests that we are currently delivering two standards of care for pelvic trauma, depending on the day and time of admission. LEVEL OF EVIDENCE: Therapeutic study, level II.


Subject(s)
Embolization, Therapeutic/statistics & numerical data , Fractures, Bone/therapy , Pelvic Bones/injuries , Pelvis/injuries , Adult , Aged , Blood Transfusion/statistics & numerical data , Female , Fractures, Bone/complications , Fractures, Bone/diagnostic imaging , Hemorrhage/etiology , Hemorrhage/therapy , Humans , Male , Middle Aged , Pelvic Bones/diagnostic imaging , Pelvis/diagnostic imaging , Quality of Health Care/statistics & numerical data , Radiology, Interventional/statistics & numerical data , Retrospective Studies , Shock, Hemorrhagic/etiology , Shock, Hemorrhagic/therapy , Time Factors , Tomography, X-Ray Computed , Young Adult
17.
Laryngoscope ; 120 Suppl 4: S132, 2010.
Article in English | MEDLINE | ID: mdl-21225730

ABSTRACT

EDUCATIONAL OBJECTIVES: At the conclusion of this presentation, the participants should be able to discuss how imaging and intra-operative facial nerve monitoring may be used in the removal of selected intraparotid foreign body without parotidectomy and dissection of the facial nerve. OBJECTIVES: 1) To present a rare case of a metallic intraparotid foreign body introduced as a projectile; 2) to discuss how CT images were used to guide the surgical exploration; and 3) To discuss the surgical approach used to retrieve an intraparotid foreign body without facial nerve dissection. STUDY DESIGN: This is a clinical case report with a review of literature. METHODS: We present the pertinent history and physical examination findings. We discuss the CT images. The technique of surgical exploration and foreign body retrieval is presented. RESULTS: This is the case of a man who presented to the emergency department with a metallic foreign body lodged in the parotid introduced accidentally as a projectile. CT images were analyzed and the patient underwent successful removal of the intraparotid foreign body with out parotidectomy and facial nerve dissection via a posterior approach and using facial nerve monitoring. CONCLUSION: Selected intraparotid foreign bodies may be removed without parotidectomy and facial nerve dissection if imaging shows it can be approached safely and intra-operative facial nerve monitoring is used.


Subject(s)
Facial Nerve , Foreign Bodies/surgery , Parotid Gland/injuries , Parotid Gland/surgery , Wounds, Penetrating/surgery , Aged , Humans , Male
18.
J Med Entomol ; 46(4): 942-51, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19645301

ABSTRACT

Imported from Africa in the 1700s and despite frequent modern eradication efforts, Amblyomma variegatum (F.) spread through the Caribbean by cattle transport, small ruminants, and migrating birds. A. variegatum is a vector for Rickettsia africae, the causative agent of African tick bite fever, and Ehrlichia ruminantium, the causative agent of heartwater. We examined 95 A. variegatum and six Rhipicephalus (Boophilus) microplus (Canestrini) collected from cattle at an abattoir in Antigua. Engorged tick extracts adsorbed on Nobotu filter paper strips and new nested polymerase chain reaction (PCR) assays for E. ruminantium and Dermatophilus congolensis were used to evaluate these ticks for the presence of these pathogenic bacteria. Amblyomma ticks (62.4%) contained R. africae DNA by PCR/restriction fragment length polymorphism analysis and DNA sequencing of the OmpA and 17-kDa antigen genes. Twenty Amblyomma and two Rh. microplus contained E. ruminantium DNA. No E. chaffeensis, Anaplasma phagocytophilum, Coxiella burnetii, or D. congolensis DNA was detected in these ticks. The continued presence of Am. variegatum in the Caribbean poses a significant risk of infection in cattle with E. ruminantium and in humans by R. africae. Eradication efforts are essential to prevent the further spread of Am. variegatum.


Subject(s)
DNA, Bacterial/chemistry , Ehrlichia ruminantium/isolation & purification , Rickettsia/isolation & purification , Ticks/microbiology , Animals , Caribbean Region , Cattle , Ehrlichia ruminantium/genetics , Polymerase Chain Reaction , Rickettsia/genetics
19.
Proc Natl Acad Sci U S A ; 101(40): 14503-8, 2004 Oct 05.
Article in English | MEDLINE | ID: mdl-15448211

ABSTRACT

Merkel cell-neurite complexes are somatosensory receptors that initiate the perception of gentle touch. The role of epidermal Merkel cells within these complexes is disputed. To ask whether Merkel cells are genetically programmed to be excitable cells that may participate in touch reception, we purified Merkel cells from touch domes and used DNA microarrays to compare gene expression in Merkel cells and other epidermal cells. We identified 362 Merkel-cell-enriched transcripts, including neuronal transcription factors, presynaptic molecules, and ion-channel subunits. Antibody staining of skin sections showed that Merkel cells are immunoreactive for presynaptic proteins, including piccolo, Rab3C, vesicular glutamate transporter 2, and cholecystokinin 26-33. These data indicate that Merkel cells are poised to release glutamate and neuropeptides. Finally, by using Ca(2+) imaging, we discovered that Merkel cells have L- and P/Q-type voltage-gated Ca(2+) channels, which have been shown to trigger vesicle release at synapses. These results demonstrate that Merkel cells are excitable cells and suggest that they release neurotransmitters to shape touch sensitivity.


Subject(s)
Merkel Cells/physiology , Animals , Cell Separation , Gene Expression Profiling , Ion Channels/genetics , Mechanotransduction, Cellular , Mice , Mice, Transgenic , Nerve Tissue Proteins/genetics , Neurons, Afferent/physiology , Oligonucleotide Array Sequence Analysis , Synaptic Transmission , Transcription Factors/genetics
20.
Biochemistry ; 41(6): 1778-85, 2002 Feb 12.
Article in English | MEDLINE | ID: mdl-11827522

ABSTRACT

8-(Hydroxymethyl)-3,N(4)-etheno-C (8-HM-epsilonC) is an exocyclic adduct resulting from the reaction of dC with glycidaldehyde, a mutagen and animal carcinogen. This compound has now been synthesized and its phosphoramidite incorporated site-specifically into a defined 25-mer oligonucleotide. In this study, the mutagenic potential of this adduct in the 25-mer oligonucleotide was investigated in an in vitro primer-template extension assay using four mammalian DNA polymerases. The miscoding potentials were also compared to those of an analogous derivative, 3,N(4)-etheno C (epsilonC), in the same sequence. Both adducts primarily blocked replication by calf thymus DNA polymerase alpha at the modified base, while human polymerase beta catalyzed measurable replication synthesis through both adducts. Nucleotide insertion experiments showed that dA and dC were incorporated by pol beta opposite either adduct, which would result in a C --> T transition or C --> G transversion. Human polymerase eta, a product of the xeroderma pigmentosum variant (XP-V) gene, catalyzed the most efficient bypass of the two lesions with 25% and 32% for 8-HM-epsilonC and epsilonC bypassed after 15 min. Varying amounts of all four bases opposite the modified bases resulted with pol eta. Human polymerase kappa primarily blocked synthesis at the base prior to the adduct. However, some specific misincorporation of dT resulted, forming an epsilonC.T or 8-HM-epsilonC.T pair. From these data, we conclude that the newly synthesized glycidaldehyde-derived adduct, 8-HM-epsilonC, is a miscoding lesion. The bypass efficiency and insertion specificity of 8-HM-epsilonC and epsilonC were similar for all four polymerases tested, which could be attributed to the similar planarity and sugar conformations for these two derivatives as demonstrated by molecular modeling studies.


Subject(s)
Anti-Bacterial Agents/toxicity , Bacterial Proteins , Carcinogens/toxicity , Cytosine/toxicity , DNA Adducts/toxicity , DNA-Directed DNA Polymerase/metabolism , Peptides , Aldehydes , Alkylating Agents , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Bacteriocins , Base Pairing , Base Sequence , Binding Sites , Carcinogens/chemical synthesis , Carcinogens/chemistry , Cytosine/analogs & derivatives , Cytosine/chemical synthesis , Cytosine/chemistry , DNA/chemistry , DNA/metabolism , DNA Adducts/chemical synthesis , DNA Adducts/chemistry , DNA Replication/drug effects , Epoxy Compounds , Models, Molecular , Nucleic Acid Conformation
SELECTION OF CITATIONS
SEARCH DETAIL
...