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Biomedical subjects

K Erickson

Publications and source records attributed to K Erickson.

At least 19 recordsLinked to original sources
PubMed2004

Characterization of F21.A, a monoclonal antibody that recognize a leucocyte surface antigen for killer whale homologue to beta-2 integrin.

The specificity of F21.A, a monoclonal antibody raised against bottlenose dolphin leucocytes, was characterized in killer whale on the basis of immunoprecipitation of a protein of 94 kDa, as well as flow cytometric analysis. While minimally expressed on resting cells, F21.A labeled a homologue to beta-2 integrin in 89-97% of PMA-activated neutrophils, 53-66% of activated monocytes, and activated B cells but not T cells. Activation of neutrophils reached its maximum 10 min after PMA stimulation. F21.A did not label intracellular stores as did both cross-reacting anti-canine CD11b and CD18, suggesting that an activation-induced conformational change would expose a neoepitope recognized by F21.A. F21.A labeling was largely inhibited by pre-incubation with plasma, suggesting a binding site closely related to that for fibrinogen. In vitro phagocytosis and respiratory burst were almost fully inhibited upon pre-incubation with F21.A, demonstrating its functional importance. This antibody is foreseen as a possible valuable diagnostic and research tool in cetacean immunology.

Animals↗
PubMed2004

Using chaotic interrogation and attractor nonlinear cross-prediction error to detect fastener preload loss in an aluminum frame.

Structural health monitoring is an important field concerned with assessing the current state (or "health") of a structural system or component with regard to its ability to perform its intended function appropriately. One approach to this problem is identifying appropriate features obtained from time series vibration responses of the structure that change as structural degradation occurs. In this work, we present a novel technique adapted from the nonlinear time series prediction community whereby the structure is excited by an applied chaotic waveform, and predictive maps built between structural response attractors are used as the feature space. The structural response is measured at several points on the structure, and pairs of attractors are used to predict each other. As the dynamics of the structure change due to damage, the prediction error rises. This approach is applied to detecting the preload loss in a bolted joint in an aluminum frame structure.

Journal Article↗
PubMed2003

Stillbirth in obstetric practice: report of survey findings.

OBJECTIVE: Stillbirth affects a large portion of the population and results in mortality rates comparable to those of preterm delivery and sudden infant death syndrome combined. Despite the large burden, little information is available to offer patients regarding etiology, treatment or prevention for a subsequent pregnancy. METHODS: We surveyed a sample of Fellows of the American College of Obstetricians and Gynecologists to determine the practice patterns in the management of stillbirth. RESULTS: The majority of Fellows agreed on the definition of stillbirth; however, their approach to treatment and prevention varied. A majority of Fellows believed that research on understanding stillbirth was of national importance. CONCLUSIONS: A comprehensive educational effort to include current knowledge regarding causes and management, standardized diagnostic procedures, death registration and case review is recommended to improve obstetric care of those with a stillbirth.

Adult↗
PubMed2001

Obstetrician-gynecologists' knowledge and training about antenatal corticosteroids.

OBJECTIVE: To characterize the clinical decisions, knowledge, opinions, and education of obstetricians and gynecologists about antenatal corticosteroids. METHODS: Questionnaires mailed to 1020 ACOG Fellows included items on demographics, knowledge, clinical practice patterns, and educational background regarding antenatal corticosteroids. RESULTS: The survey response rate was 47.8%. Almost all respondents (94%) reported administering antenatal corticosteroids, with reduction of respiratory distress syndrome (82%) as the primary reason for antenatal corticosteroid administration. Most (59.2%) were unaware of newly recognized associations between multiple administrations of corticosteroids and fetal growth restriction. In hypothetical clinical situations, responses by physicians who completed their residency training before 1970 indicated less likelihood to administer corticosteroids when administration is relatively indicated per National Institutes of Health (NIH) and ACOG guidelines than those trained later (P <.001). Only 8% of the entire sample rated their knowledge of antenatal corticosteroids as comprehensive; most (68%) rated it as adequate. Respondents rated residency training as a much better source of antenatal corticosteroid knowledge than medical school. CONCLUSION: Most obstetrician-gynecologists reported using antenatal corticosteroids; however, in general, many were not aware of more recent information regarding potential risks. This survey suggests that a multipronged educational approach is warranted to update obstetrician-gynecologists about antenatal corticosteroids.

Adult↗
PubMed2001

Group B streptococcal disease prevention practices of obstetrician-gynecologists.

OBJECTIVE: To describe group B streptococcal (GBS) disease prevention practices of obstetrician-gynecologists. METHODS: We surveyed 1019 ACOG Fellows-the 419 members of the Collaborative Ambulatory Research Network (CARN) and 600 randomly selected non-CARN Fellows. RESULTS: There were 601 eligible respondents. More than 95% in both the CARN and the non-CARN groups reported adopting one of three GBS prevention strategies. The most commonly reported strategy was a combination approach not described in the consensus guidelines. The second most common strategy was the screening-based strategy; the risk-based strategy was third. Most respondents provided GBS information to all prenatal patients, but those using a risk-based strategy and those in solo practice were less likely to do so. Less than 60% in each group used penicillin as their first choice for GBS prophylaxis. More than 20% in each group who routinely screened for GBS did not collect both vaginal and rectal cultures. Respondents rated ACOG publications as the most important influence on their GBS prevention approach. CONCLUSION: Almost all ACOG Fellows have adopted a GBS prevention strategy. The importance of providing GBS prevention information to all patients, use of penicillin, and collection of both vaginal and rectal cultures should be reinforced.

Female↗
PubMed2001

Neuropsychological functioning in early hydrocephalus: review from a developmental perspective.

Children with hydrocephalus have deficits in several neuropsychological domains. The most notable are motor, visuoperceptual, and visuomotor function. These deficits are multiply determined and depend on the etiology and severity of the hydrocephalus to a large extent. Corpus callosum abnormalities resulting from stretching of callosal fibers and other cortical white matter tracts are implicated as contributory to these deficits. Enlarged ventricles and associated compression of posterior cortical areas also correlate with cognitive impairment. Distinguishing which cognitive domain negatively impacts on the child's functioning and which domains influence behavior in isolation or in combination has been the subject of numerous studies. Developmentally, we know little about the emergence of neuropsychological functioning in children with hydrocephalus. Study of the effects of hydrocephalus at different stages of development is useful to clinicians and researchers interested in the impact of diffuse neurophysiological damage on cognition in the developing brain. The medical and neuropsychological literature have begun to inform about these effects. The core deficits in hydrocephalus have yet to be explicated and a focus on investigations that answer these questions is required. This review summarizes the current knowledge about neurocognitive sequelae of hydrocephalus.

Brain Damage, Chronic↗
PubMed2001

Practice trends in outpatient obstetrics and gynecology: findings of the Collaborative Ambulatory Research Network, 1995--2000.

UNLABELLED: Historically, obstetrics and gynecology has been a medical/surgical specialty focusing on women's health and reproductive concerns during the childbearing years. Newer responsibilities-for example, in primary care, gerontology, and genetics-require Ob-Gyns to draw upon a base of medical knowledge that traditionally was not considered germane to their practices. Ob-Gyns are increasingly providing more primary care services to their patients; consequently, the field has expanded considerably. The Collaborative Ambulatory Research Network (CARN) was created in 1990 as a vehicle for investigating issues pertinent to women's health and to the practice of obstetrics and gynecology in the outpatient setting. This article summarizes the findings of CARN studies from 1995 to 2000, covering a range of topics related to women's health across the life cycle, including, but not limited to perinatal care. Topics include nutrition, infectious disease, hormone replacement therapy, psychosocial issues, and genetic testing in obstetric and gynecologic practice. Each study produced a picture of current practice patterns and knowledge of the physicians surveyed. Findings on knowledge, attitudes, and practices varied widely. Overall, Ob-Gyns were knowledgeable and consistent in more traditional areas of practice. Conversely, inconsistencies were observed in newer areas. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians LEARNING OBJECTIVES: After completion of this article, the reader will be able to define what the Collaborative Ambulatory Research Network (CARN) involves, describe how CARN obtains its data, and summarize some of the findings of CARN from the years 1995 to 2000.

Adult↗
PubMed2001

Preterm birth: associated neuroendocrine, medical, and behavioral risk factors.

Increased CRH secretion by the placenta of pregnant women has been associated with preterm birth. Certain indices of risk, both medical and psychosocial in nature, have been linked to preterm delivery. Levels of total, bound, and free CRH, CRH-binding protein (CRH-BP), and cortisol were measured prospectively in a large sample of pregnant Danish women who delivered preterm and term infants. Measures of maternal serum hormones were taken at 7--23 and 27--37 weeks gestation and, for those who delivered at term, at 37--43 weeks gestation. At 7--23 weeks gestation, maternal levels of total CRH (P = 0.01), bound CRH (P = 0.03), and CRH-BP (P = 0.01) were higher in the preterm than in the term group. At 27--37 weeks gestation, levels of total CRH (P < 0.0001), bound CRH (P < 0.0001), free CRH (P < 0.0001), and cortisol (P < 0.0001) were all higher in the preterm than the term group, whereas levels of CRH-BP (P < 0.0001) were lower in the preterm than in the term group. The best medical and behavioral factors associated with preterm delivery were, respectively, previous preterm delivery (P < 0.0001) and engagement in certain risk-taking behaviors (P = 0.008). The positive relations between preterm delivery and various adverse medical and socioeconomic variables with increases in placental secretion of CRH suggest that the latter may participate in the pathophysiology of preterm delivery.

Adult↗
PubMed2000

Communicating pain and pain management needs after surgery.

This descriptive study explored how patients communicate their pain and pain management needs after surgery. Thirty postoperative patients were interviewed. The majority described avoiding or delaying communicating their pain at some point during their hospitalization. Reasons for decreased pain communication included not wanting to complain; not wanting to take the provider away from other patients; avoiding unpleasant analgesic side effects; and not wanting to take "drugs." Postoperative patients may be unclear about their role in pain management. Pain management communication problems identified in this study could be used to design intervention studies to improve pain communication and consequent pain relief.

Adult↗
PubMed2000

Obstetrician-gynecologists' opinions and attitudes on the role of genetics in women's health.

Our objective was to describe gynecologists' current practice patterns and opinions on genetic screening and their perceived importance of genetic screening within individual practices. A questionnaire survey was sent to 1248 American College of Obstetrics and Gynecology (ACOG) Fellows, of whom 564 (45%) responded. Results from the 428 respondents providing genetic screening for heritable diseases or disorders are reported. Forty-four percent of respondents believe advances in the treatment of genetic diseases are likely in the next 10 years. Currently, however, genetics in gynecological practice receives infrequent attention. Twenty-four percent of respondents do not routinely review family histories at gynecological visits, 39% rate genetic issues as last among priorities in the office, and only 14% obtain consent for the DNA tests that they initiate. Although 21.3% identified themselves as sole providers of genetic information and counseling to their patients, most (65.4%) note they are not confident of their knowledge of genetics, particularly concerning breast and ovarian cancer. For obstetrician-gynecologists to keep pace with the rapid changes in genetics, further education and assimilation of genetics into the routine office practice will need to occur. Not currently viewed as a priority among practitioners, issues of genetic knowledge, ethics, and test interpretation will soon need attention. National organizations, continuing medical education, and existing genetic centers will need to meet these recognized demands.

Adult↗
PubMed1998

Sodium butyrate upregulates Kupffer cell PGE2 production and modulates immune function.

The immunosuppressive effect of portal venous blood transfusions in organ transplantation has been well established and may be mediated by increased Kupffer cell production of the immunosuppressive arachidonic acid metabolite prostaglandin E2 (PGE2). In this study, butyrate, a short-chain fatty acid known to enhance gene transcription, is hypothesized to enhance Kupffer cell PGE2 production by altering cyclooxygenase or phospholipase A2 (PLA2) activity, thus augmenting the immunosuppressive effect of portal venous transfusion. Lewis rats were given a portal venous transfusion of Wistar-Firth blood or saline 1 h prior to Kupffer cell harvest. The in vitro effects of butyrate on Kupffer cell PGE2 production, cyclooxygenase, and PLA2 activity were assessed. Kupffer cell tumor necrosis factor-alpha (TNFalpha) production was also assessed due to its sensitivity to PGE2 and its proinflamatory effects. Kupffer cells from portally transfused animals produced significantly more PGE2 than saline-transfused controls. Addition of butyrate to the culture medium further increased PGE2 production by as much as sevenfold in Kupffer cells of portally transfused animals. Other short-chain fatty acids, propionate and hexanoate, did not increase PGE2 production. Butyrate added to Kupffer cells from transfused animals slightly upregulated inducible cyclooxygenase (COX-2) mRNA levels as measured by both Northern blot and reverse-transcriptase polymerase chain reaction and increased PLA2 activity fivefold as measured by Western blot. Kupffer cell immune function was also affected by in vitro butyrate treatment with a significant decrease in the production of TNFalpha. Thus, butyrate may be a useful immunoregulatory agent in organ transplantation protocols which seek to enhance transcription of immunosuppressive molecules.

Animals↗
PubMed1998

Selective targeting of Kupffer cells with liposomal butyrate augments portal venous transfusion-induced immunosuppression.

BACKGROUND: Enhanced Kupffer cell production of the immunosuppressive arachidonic acid metabolite prostaglandin E2 (PGE2) has been shown to be a mechanism of the immunosuppressive effect of portal venous transfusions (PVT). Butyrate, a four-carbon short-chain fatty acid, has received increased attention because of its ability to enhance gene transcription. This study tested the hypothesis that the intrahepatic delivery of butyrate enhances Kupffer cell PGE2 production and thus augments the immunosuppressive effect of PVT. METHODS: Butyrate was incorporated into liposomes and administered intravenously to Lewis rats. Control rats were administered liposomes without butyrate. Twenty-four hours after liposome injection, rats were administered a PVT of 1 ml of Wistar-Furth blood. Kupffer cells were isolated, and PGE2 and tumor necrosis factor-alpha levels were measured in the culture medium after 24 hr. Additionally, Kupffer cells from butyrate-treated and control animals were added to one-way mixed lymphocyte reaction cultures. RESULTS: Intrahepatic delivery of butyrate via liposomes increased Kupffer cell PGE2 (3800+/-1220 vs. 1010+/-119 pg/ml, P<0.05) and decreased tumor necrosis factor-alpha (1670+/-81 vs. 3360+/-415 pg/ml, P<0.01) production as compared with controls. Butyrate also augmented the Kupffer cell-mediated immunosuppression as demonstrated by significant depression of the mixed lymphocyte reaction (690+/-119 vs. 3850+/-148 cpm, P<0.01). CONCLUSION: The results support the hypothesis that intrahepatic delivery of butyrate enhances Kupffer cell PGE2 production, and specific targeting of Kupffer cells with liposomes containing immunomodulating agents such as butyrate may be a useful means of augmenting immunosuppression protocols in organ transplantation.

Animals↗
PubMed1998

Characterization of a monoclonal antibody that recognizes a lymphocyte surface antigen for the cetacean homologue to CD45R.

As part of our current efforts to develop assays and reagents to study the immune system of marine mammals, and in view of the effort currently made to develop monoclonal antibodies to cell surface proteins of lymphocyte subsets in different species, the present paper reports on the characterization of a monoclonal antibody against the homologue of CD45R on cetacean lymphocytes. The specificity of this antibody has been characterized on the basis of immunoprecipitation of the antigen it recognized, immunoperoxidase staining on cetacean lymph node and thymus sections, as well as one and two-colour flow cytometric analysis of cetacean peripheral blood mononuclear cells and single-cell suspensions of thymus, lymph node and spleen. Anticetacean CD45R (F21.H) immunoprecipitated proteins of 180, 200 and 220 x 10(3) MW, with the 180 x 10(3) MW from being predominantly expressed on T cells and the 220 x 10(3) MW form expressed predominantly on B cells and thymocytes F21.H labelled all B cells and a proportion of T cells on single-cell suspensions of spleen cells. CD45R- killer whale peripheral blood lymphocytes expressed a higher density of CD2 than CD45R+, a characteristic of memory T cells. Killer whale T lymphocytes also lost the expression of CD45R upon activation with concanavalin A (Con A) and phytohaemagglutinin (PHA). This is the first report of a monoclonal antibody to CD45R in cetaceans, and this antibody is foreseen as a possible valuable diagnostic and research tool to assess immune functions of captive and wild cetaceans as part of the evaluation of their health status.

Animals↗
PubMed1997

Portal venous transfusion up-regulates Kupffer cell cyclooxygenase activity: a mechanism of immunosuppression in organ transplantation.

Portal venous transfusions (PVTs) of blood have been shown to induce significant immunosuppression in animal models of organ transplantation. A proposed mechanism of PVT-induced immunosuppression is via alteration of Kupffer cell arachidonic acid metabolism with increased secretion of the suppressive metabolite prostaglandin E2 (PGE2). This study assessed the hypothesis that PVT increases Kupffer cell PGE2 production via up-regulation of Kupffer cell phospholipase A2 (PLA2) as well as constitutive (COX1) and inducible (COX2) cyclooxygenase. Kupffer cells from Lewis rats were harvested 1 hr after PVT with either 1 ml of Wistar-Furth blood, systemic transfusion (SVT), or saline via portal vein (PVSal). After lipopolysaccharide stimulation, 24-hr Kupffer cell supernatant fractions were assayed for PGE2. PGE2 was increased after SVT (1465+/-234 pg/ml) compared with PVSal (597+/-99; P<0.01). PVT increased Kupffer cell PGE2 (5370+/-533; P<0.001 vs. SVT and vs. PVSal) even more substantially. Kupffer cells from PVT-treated rats were then cultured in the presence of inhibitors of PLA2, COX1, or COX2. When Kupffer cells were treated with mepacrine to inhibit PLA2 (5575+/-453 pg/ml), PGE2 production was not different from that by PVSal-treated controls (6467+/-614 pg/ml), but when Kupffer cells were incubated in the presence of the COX1 inhibitor flurbiprofen (3512+/-407 pg/ml) or the COX2 inhibitor nimesulide (2800+/-830 pg/ml), production was decreased 46.7% and 56.7%, respectively, over control activity without added inhibitor. PVT also increased Kupffer cells COX1 and COX2 mRNA as measured by Northern blot. Heart transplants were then performed from Wistar-Furth donors into Lewis recipients at the time of PVT, SVT, PVSal, or PVT + indomethacin (COX1/2 inhibitor). PVT prolonged allograft survival (12.0+/-0.9 days) compared with PVSal (6.3+/-0.3; P<0.01) or SVT (6.3+/-0.3; P<0.04). Indomethacin shortened graft survival when given with PVT (6.5+/-0.3 days). In summary, PVT increased Kupffer cell PGE2 production, up-regulated transcription of Kupffer cells COX1 and COX2 mRNA, and prolonged cardiac allograft survival. COX1/2 inhibition abrogated the effect of PVT. The results indicated that the immunosuppressive effect of PVT may be mediated by up-regulation of Kupffer cell COX1 and COX2. Manipulation of Kupffer cell arachidonic acid metabolism may be useful in augmentation of PVT-induced immunosuppression.

Animals↗
PubMed1997

Localization of NADPH diaphorase in the thoracolumbar and sacrococcygeal spinal cord of the dog.

The distribution of NADPH-d activity and NOS-immunoreactivity in the spinal cord of the dog was studied to evaluate the role of nitric oxide in lumbosacral afferent and spinal autonomic pathways. At all levels of the spinal cord examined, NADPH-d staining and NOS-immunoreactivity were present in neurons and fibers in the superficial dorsal horn, dorsal commissure and in neurons around the central canal. Sympathetic preganglionic neurons in the rostral lumbar segments identified by choline acetyl transferase (ChAT) immunoreactivity exhibited prominent NADPH-d and and NOS-immunoreactive staining; whereas the ChAT-immunoreactive parasympathetic preganglionic neurons in the sacral segments were not stained. The most prominent NADPH-d activity in the sacral segments occurred in fibers extending form Lissauer's tract through lamina I along the lateral edge of the dorsal horn to the region of the sacral parasympathetic nucleus. These fibers were prominent in the S1-S3 segments but not in adjacent segments (L5-L7 and Cx1 or in thoracolumbar segments. The NADPH-d fibers were not NOS-immunoreactive, but did overlap with a prominent fiber bundle containing vasoactive intestinal polypeptide immunoreactivity in the sacral spinal cord. These results indicate that nitric oxide may function as a transmitter in thoracolumbar sympathetic preganglionic neurons, but not in sacral parasympathetic preganglionic neurons. The functional significance of the NADPH-d positive, NOS-negative fiber bundle on the lateral edge of the sacral dorsal horn remains to be determined. However, based on anatomical studies in other species it seems reasonable to speculate that the fiber tract represents, in part, visceral afferent projections to the sacral parasympathetic nucleus.

Animals↗
PubMed1995

Expression of muscarinic receptor subtype mRNA in the human ciliary muscle.

PURPOSE: To investigate the expression of the muscarinic receptor (mAChR) subtypes (m1, m2, m3, m4, and m5) in the human ciliary muscle. METHODS: cDNA probes specific for the m1 to m5 subtypes were used to characterize the expression of subtype-specific mRNAs by in situ hybridization and Northern blot analysis on a cell line derived from human ciliary muscle tissue (H7CM), sectioned tissue from four donors, and fresh human ciliary muscle tissue from three donors. RESULTS: Messenger RNA for m2, m3, and m5 was detected in situ hybridization and Northern blot analysis in the H7CM cell line and in human ciliary muscle tissue from the donors. In human ciliary muscle tissues, the expression of mRNA of the m2 and m3 subtypes was more prominent in the circular portion than in the longitudinal portion. In contrast, mRNA for the m5 subtype was greater in the longitudinal portion than in the circular portion. Additionally, Northern blot analysis showed that m1 and m4 were expressed in ciliary muscle tissue. CONCLUSION: These studies show that the human ciliary muscle definitely expresses the mRNA of subtypes m2, m3, and m5, and may also express the mRNA of m1 and m4. Although the expression of mRNA for the m2, m3, and m5 subtypes differed between the circular and longitudinal portions of the ciliary muscle, the strong expression of all three subtypes of muscarinic receptors by both portions demonstrates that the differential distribution of muscarinic subtypes probably is not responsible for the dissociation between outflow facility and accommodation that can occur under certain conditions.

Adult↗