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Biomedical subjects

C L Anderson

Publications and source records attributed to C L Anderson.

At least 37 records · Page 2Linked to original sources
PubMed1999

Ultrastructure of Myxidium trachinorum sp. nov. from the gallbladder of the lesser weever fish Echiichthys vipera.

Myxidium trachinorum sp. nov. is described from the gallbladder of the lesser weever fish Echiichthys vipera. Pseudoplasmodia attach themselves to the gallbladder epithelium by filose processes, which are inserted between host cells. Pseudoplasmodia undergo endogenous cell formation at the secondary and tertiary levels. In the proliferative cycle, primary and endogenous cells are packed with digestive vacuoles formed by phagocytosis. In the sporogonic cycle the pseudoplasmodium becomes a pericyte enclosing two secondary cells (lacking digestive vacuoles) in a vacuole. These give rise to five cells each two valvogenic, two capsulogenic and a binucleate sporoplasm, which mature into spores. Comparison of the disporic M. trachinorum with polysporic species of Myxidium revealed significant differences in plasmodial ultrastructure, especially their attachments to host cells, surface characteristics and mode of nutrition, and in formation of generative cells. These suggest that the genus Myxidium may require revision.

Animals↗
PubMed1999

Molecular data implicate bryozoans as hosts for PKX (phylum Myxozoa) and identify a clade of bryozoan parasites within the Myxozoa.

Proliferative kidney disease (PKD), a condition associated with high mortality in salmonid fish, represents an abnormal immune response to the presence of an enigmatic myxozoan, which has been designated simply as PKX organism because its generic and specific status are obscure. Phylogenetic analyses of partial sequences of the 18S rDNA of PKX and of myxozoan parasites infecting the bryozoans Cristatella mucedo, Pectinatella magnifica and Plumatella rugosa, including the previously named Tetracapsula bryozoides from C. mucedo, showed that these taxa represent a distinct clade that diverged early in the evolution of the Myxozoa before the radiation of the other known myxozoan genera. A common feature of the myxozoans in this clade may be the electron-dense sporoplasmosomes with a lucent bar-like structure, which occur in T. bryozoides and PKX but not in the myxozoans belonging to the established orders Bivalvulida and Multivalvulida. Variation of 0.5-1.1% was found among the PKX 18S rDNA sequences obtained from fish from North America and Europe. The 18S rDNA sequence for T. bryozoides showed that it is a distinct taxon, not closely related to PKX but some sequences from myxozoans infecting 2 of the bryozoan species were so similar to those of PKX as to be indistinguishable. Other sequences from the new myxozoans in bryozoans at first appeared distinct from PKX in a maximum likelihood tree but, when analysed further, were also found to be phylogenetically indistinguishable from PKX. We propose that at least some variants of these new myxozoans from bryozoans are able to infect and multiply in salmonid fish, in which they stimulate the immune reaction and cause PKD but are unable to form mature spores to complete their development.

Animals↗
PubMed1999

Polymorphic X-chromosome inactivation of the human TIMP1 gene.

X inactivation silences most but not all of the genes on one of the two X chromosomes in mammalian females. The human X chromosome preserves its activation status when isolated in rodent/human somatic-cell hybrids, and hybrids retaining either the active or inactive X chromosome have been used to assess the inactivation status of many X-linked genes. Surprisingly, the X-linked gene for human tissue inhibitor of metalloproteinases (TIMP1) is expressed in some but not all inactive X-containing somatic-cell hybrids, suggesting that this gene is either prone to reactivation or variable in its inactivation. Since many genes that escape X inactivation are clustered, we examined the expression of four genes (ARAF1, ELK1, ZNF41, and ZNF157) within approximately 100 kb of TIMP1. All four genes were expressed only from the active X chromosome, demonstrating that the factors allowing TIMP1 expression from the inactive X chromosome are specific to the TIMP1 gene. To determine if this variable inactivation of TIMP1 is a function of the hybrid-cell environment or also is observed in human cells, we developed an allele-specific assay to assess TIMP1 expression in human females. Expression of two alleles was detected in some female cells with previously demonstrated extreme skewing of X inactivation, indicating TIMP1 expression from the inactive chromosome. However, in other cells, no expression of TIMP1 was observed from the inactive X chromosome, suggesting that TIMP1 inactivation is polymorphic in human females.

Alleles↗
PubMed1999

Household poisoning exposure among children of Mexican-born mothers: an ethnographic study.

OBJECTIVE: To explore reasons for high rates of unintentional poisoning among Latino children under 5 years old. DESIGN: Ethnographic interviews were carried out using a sample of mothers identified via door-to-door canvassing in an area with documented high injury rates among Latino children. Interviews included many open-ended and follow-up questions to elicit a detailed family history and emphasized observation of conditions and behaviors in the homes. SETTING: Low-income neighborhoods of Southern California. SUBJECTS: Fifty mothers born in Mexico with children under 5 years old. RESULTS: Children were exposed to potential poisoning agents in more than 80% of homes. Contributory factors related to culture included favorable attitudes toward iron as a healthful substance; extensive use of products that lack child-resistant packaging, such as rubbing alcohol and medicines from Mexico; high prevalence of shared housing; limited familiarity with toxic household chemicals not widely used in Mexico; and inability to read warning labels in English. CONCLUSION: Current Poison Control Center outreach efforts should be expanded. Clinicians are uniquely positioned to advise parents about the safe use and storage of toxic substances, including widely used products lacking child-resistant packaging. Medicines should be labeled in Spanish for those who do not know English.

Anthropology, Cultural↗
PubMed1999

Physiological determinants of performance on an indoor military obstacle course test.

Obstacle courses (OCs), physical challenge courses, and confidence courses are valuable in training and assessing military troops. However, OCs are not well characterized with regard to physical demands and requisite abilities. The purpose of this study was to evaluate the physical capabilities associated with success on an OC. Male subjects (N = 47) were assessed on an OC, skinfolds, upper and lower body aerobic and anaerobic power, muscular strength, and endurance. Faster performers were lighter (p < 0.003), leaner, and, relative to body weight, averaged greater arm anaerobic peak and mean power, leg aerobic power, one-repetition maximum leg press, and one-repetition maximum latissimus dorsi pull-down, than slower performers. There were significant correlations between OC time and weight (0.59), percent fat (0.54), anaerobic leg mean power (-0.43), arm anaerobic peak (-0.48) and mean power (-0.48), and arm (-0.51) and leg aerobic power (-0.53), all expressed relative to body weight. A three-variable regression model accounted for 35% of the variation in OC time. Good performers on this OC displayed many diverse physical capabilities.

Adult↗
PubMed1998

Chimeric receptors composed of phosphoinositide 3-kinase domains and FCgamma receptor ligand-binding domains mediate phagocytosis in COS fibroblasts.

Receptors for the Fc portion of IgG (FcgammaR) initiate phagocytosis of IgG-opsonized particles by a process involving the assembly of a multi-molecular signaling complex. Several members of this complex have been identified, including Src family kinases, Syk/ZAP 70 family kinases, and phosphoinositide 3-kinase (PI3-K). To test directly the role of PI3-K in mediating phagocytosis, we assessed the phagocytic ability of chimeric receptors composed of FcgammaR extracellular and transmembrane domains fused to regions of the p85 subunit of PI3-K. We found that chimeric receptors with cytoplasmic tails composed of the entire p85 subunit of PI3-K or the inter-Src homology 2 portion of p85 triggered phagocytosis in transfected COS fibroblasts. These two chimeras also showed phosphoinositide kinase activity in vitro when immunoadsorbed. In contrast, a chimera containing only the carboxyl-terminal Src homology 2 domain of p85 that does not interact with the catalytic p110 subunit of PI3-K did not trigger phagocytosis, nor did it show kinase activity in vitro. These data suggest that localization and direct activation of PI3-K at the site of particle attachment is sufficient to trigger the process of phagocytosis.

Animals↗
PubMed1998

Functional separation of pseudopod extension and particle internalization during Fc gamma receptor-mediated phagocytosis.

Receptors for the Fc portion of immunoglobulin (Ig)G (Fc gamma R) mediate phagocytosis of IgG-opsonized particles by a process that can be divided into four major steps: receptor-ligand binding, pseudopod extension, internalization, and lysosomal fusion. We have expressed single classes of Fc gamma R in COS fibroblasts to examine the structural determinants necessary to complete the four steps of phagocytosis. Using phase contrast, fluorescence, confocal, and electron microscopy we have demonstrated that Fc gamma R-expressing COS cells can phagocytose in a manner similar to that of professional phagocytes. We have further analyzed the capacity of the three classes of Fc gamma R to phagocytose, placing special emphasis on the Fc gamma RIA-gamma chain complex, which allowed us to examine independently the roles of the ligand-binding unit (Fc gamma RIA) and the signaling unit (gamma chain). We found that receptor complexes containing a conserved tyrosine activation motif (ITAM), as found in the cytoplasmic domain of Fc gamma RIIA and in the gamma chain associated with Fc gamma RIA and Fc gamma RIIIA, readily internalized target particles. In contrast, Fc gamma RIA alone, having no ITAM, was unable to internalize target particles efficiently, but did mediate pseudopod extension. Cotransfection of gamma chain with Fc gamma RIA restored the ability of the receptor to internalize target particles. A mutant Fc gamma RIA in which the cytoplasmic domain had been deleted was also capable of mediating pseudopod extension, showing that neither the gamma chain nor the cytoplasmic domain of Fc gamma RIA were required for this step. Cytochalasin D, an inhibitor of actin polymerization, blocked particle internalization by all Fc gamma R, but did not block pseudopod extension. Staining the Fc gamma RIA COS cells for F-actin and for tyrosine phosphoproteins, we found that actin did not polymerize during Fc gamma RIA-mediated pseudopod extension, nor were tyrosine kinases activated. Our data suggest that pseudopod extension and internalization are functionally distinct steps mediated through different pathways.

Actins↗
PubMed1998

Adult attachment and long-term effects in survivors of incest.

OBJECTIVE: The aim of the study was to test the hypothesis that adult attachment is related to distress and personality disorders in incest survivors. METHOD: Adult female incest survivors recruited from the community participated in a structured interview (Family Attachment Interview; Bartholomew & Horowitz, 1991) and completed measures of current functioning (Impact of Event Scale, SCL-10, Beck Depression Inventory) and personality (MCMI-II). Complete data from 92 cases out of the total sample of 112 were analyzed. RESULTS: Analyses of variance suggested that attachment (as represented by a category) was significantly related to personality structure, with fearful individuals showing more avoidant, self-defeating, and borderline tendencies and preoccupied individuals showing more dependent, self-defeating, and borderline tendencies than secure or dismissing individuals. Results of hierarchical regression analyses suggested that attachment (as represented by four dimensions) was significantly associated with personality structure, depression and distress, and abuse severity with post traumatic stress disorder (PTSD) symptoms (intrusive thoughts and avoidance of memories) and depression. CONCLUSIONS: The findings demonstrated the propensity for insecure attachment among incest survivors. Sexual abuse severity and attachment have significant but distinct effects on longterm outcome; abuse characteristics predict classic PTSD symptoms and attachment insecurity predicts distress, depression, and personality disorders above and beyond any effects of abuse severity.

Adult↗
PubMed1998

Molecular characterization of six variant Fcgamma receptor class I (CD64) transcripts.

In humans, three distinct but closely related classes of receptors that bind the Fc portion of IgG (FcgammaRI, II and III) have been identified. FcgammaRI can bind monomeric IgG with high affinity and has a unique third extracellular domain (EC3). Three very similar genes have been characterized for FcgammaRI (A, B, C). Although the sequences are remarkably similar, a number of coding-region differences discriminate between the genes and amongst their transcripts. Six distinct FcgammaRI transcripts were analysed. Three transcripts, one from each gene, contain all six exons. Only the gene A transcript appears to encode a bona fide high affinity receptor, a three Ig-domain membrane spanning receptor that can bind monomeric IgG. Stop codons in the EC3 domains of the gene B and gene C isoforms would be predicted to generate secreted receptors. Three transcripts are alternatively spliced isoforms, one from gene A and two from gene B. One gene B transcript encodes a two Ig-domain transmembrane receptor which has structural characteristics of a low affinity FcgammaR.

Animals↗
PubMed1998

Demographic risk factors for injury among Hispanic and non-Hispanic white children: an ecologic analysis.

OBJECTIVES: To determine the effects of neighborhood levels of poverty, household crowding, and acculturation on the rate of injury to Hispanic and non-Hispanic white children. SETTING: Orange County, California. METHODS: An ecologic study design was used with census block groups as the unit of analysis. Measures of neighborhood poverty, household crowding, and acculturation were specific to each ethnic group. Poisson regression was used to calculate mutually adjusted incidence rate ratios (IRRs) corresponding to a 20% difference in census variables. RESULTS: Among non-Hispanic white children, injury rates were more closely associated with neighborhood levels of household crowding (adjusted IRR 2.36, 95% confidence interval (CI) 1.22 to 4.57) than with neighborhood poverty (adjusted IRR 1.06, 95% CI 0.89 to 1.26). For Hispanic children, the strongest risk factors were the proportion of Hispanic adults who spoke only some English (compared with the proportion who spoke little or no English, adjusted IRR 1.26, 95% CI 1.04 to 1.53) and the proportion who were US residents for < 5 years (adjusted IRR 1.20, 95% CI 1.001 to 1.43). Neighborhood levels of household crowding were not related to injury among Hispanic children (adjusted IRR 0.98, 95% CI 0.89 to 1.08), but surprisingly, neighborhood poverty was associated with lower injury rates (adjusted IRR 0.89, 95% CI 0.81 to 0.97). CONCLUSIONS: Cultural and geographic transitions, as well as socioeconomic differences, appear to contribute to differences in childhood injury rates between ethnic groups.

Acculturation↗
PubMed1998

Family, social, and cultural factors in pedestrian injuries among Hispanic children.

OBJECTIVES: In an earlier population based surveillance study of pediatric injuries, the rate of Hispanic children injured as pedestrians was 63/100,000 compared with 17/100,000 for non-Hispanic white children. The present study was designed to examine the effect of family, social, and cultural factors on the rate of pedestrian injury in a population of Hispanic children in the southwestern US. METHODS: A case-control study of pedestrian injuries among Hispanic children. The sample consisted of 98 children 0-14 years of age hospitalized as a result of a pedestrian injury and 144 randomly selected neighborhood controls matched to the case by city, age, gender, and ethnicity. Cases were compared with controls using conditional logistic regression; in the study design the odds ratio (OR) estimates the incidence rate ratio. RESULTS: The following family and cultural variables were associated with an increased risk of injury: household crowding (OR = 2.8, 95% confidence interval (CI) 1.1 to 7.1 for 1.01-1.5 persons per room, compared with < or = 1.0 persons per room), one or more family moves within the past year (OR 2.2, 95% CI 1.2 to 4.1), poverty (OR 1.9, 95% CI 1.1 to 3.3), and inability of mother (OR 3.6, 95% CI 1.3 to 10) or father (OR 5.6, 95% CI 1.5 to 20) to read well. However, children in single parent households and children whose parents did not drive a car, had less education, or were of rural origin, did not have an increased rate of injury. CONCLUSIONS: These results have implications for childhood pedestrian prevention efforts for low income, non-English speaking Hispanic populations, and perhaps for other immigrant and high risk groups. Prevention programs and materials need to be not only culturally sensitive but also designed for those with limited reading skills. In addition, environmental interventions that provide more pedestrian friendly neighborhoods must be considered.

Accidents, Traffic↗
PubMed1998

Localization of FCGR1 encoding Fcgamma receptor class I in primates: molecular evidence for two pericentric inversions during the evolution of human chromosome 1.

The human high-affinity receptor for immunoglobulin G, FcgammaRI (FCGR1), is encoded by a family of three genes that share over 95% sequence homology. Curiously, the three genes in this recently duplicated gene family flank the centromere of human chromosome 1, with FCGR1B located at 1p12 and both FCGR1A and FCGR1C located at 1q21. We have previously speculated that a pericentric inversion could account for the separation of the genes in the FCGR1 family and explain their current chromosomal location. Here we present evidence, obtained through fluorescence in situ hybridization analysis, that in the rhesus monkey (Macaca mulatta) and baboon (Papio papio) FCGR1 is located adjacent to the centromere on the chromosomal arm with greatest homology to human 1p, whereas in the chimpanzee (Pan troglodytes) it is located adjacent to the centromere on the chromosomal arm with greatest homology to human 1q. The separation of the FCGR1 gene family in humans suggests that the location of a second pericentric inversion, known to distinguish the human from the chimpanzee chromosome 1, is within the FCGR1 gene family. This finding refines the assignment of homology between the human and chimpanzee chromosomes 1.

Animals↗
PubMed1998

Factors associated with restraint use of children in fatal crashes.

OBJECTIVE: This study was designed to characterize the restraint use of children in fatal crashes and to determine factors that were related to child restraint use. METHODS: Crashes in which a vehicle occupant died were selected from the 1994 Fatal Analysis Reporting System data. Restraint use of children (0-9 years) in these crashes was characterized and examined in relation to vehicle and driver characteristics. RESULTS: Restraint use declined with increasing age of children and increasing number of occupants. Restraint use was also lower in older vehicles, in pickups and large vans, between 3 AM and 6 AM, and in rural areas. Driver characteristics associated with lower restraint use of child passengers included unrestrained drivers, younger drivers, and alcohol use at the time of crash. Driver restraint use was the strongest predictor of child restraint use. Differences in restraint use by age of the child, number of occupants, time, urban/rural area, and driver restraint use persisted in a logistic model. CONCLUSION: Restraint use in crashes is substantially lower than that in observational studies, suggesting that these studies are not reflective of high-risk conditions for crashes in which children are involved. Child occupant protection counseling must stress restraint use under all conditions of travel. Local, state, and national efforts must be aimed at increasing family occupant protection for the entire family.

Accidents, Traffic↗
PubMed1997

Beta2-microglobulin-deficient mice are resistant to bullous pemphigoid.

Recent understanding of the mechanism of immunoglobulin G (IgG) catabolism has yielded new insight into antibody-mediated diseases. We proposed that beta2-microglobulin (beta2m)-deficient mice have been protected from systemic lupus erythematosis (SLE)-like syndromes because they lack the beta2m-associated IgG protection receptor (FcRn) and therefore catabolize IgG, including pathogenic IgG autoantibodies, considerably more rapidly than normal mice. Such an hypothesis would predict that beta2m-deficient mice would also be resistant to experimental bullous pemphigoid, a disease with a pathogenesis thought to be much simpler than SLE, being the result of antibody directed toward a pathogenic epitope on the epidermal hemidesmosome that anchors basal keratinocytes to the basement membrane. To test this hypothesis, we administered pathogenic rabbit antibody directed toward the hemidesmosome to beta2m-deficient mice and to normal control mice, both intraperitoneally and intradermally, and assessed the mice clinically, histologically, and immunologically for manifestations of skin disease. We found that the beta2m-deficient mice were protected when the antibody was given intraperitoneally whereas intradermal administration resulted in blisters only slightly less severe than those seen in normal mice. These data would indicate that autoantibody-mediated inflammation might be prevented or controlled by appropriate modulation of FcRn function.

Animals↗
PubMed1997

Association of non-receptor protein tyrosine kinases with the Fc gamma RI/gamma-chain complex in monocytic cells.

To characterize the functional macromolecular complex of the high affinity receptor for IgG (Fc gamma RI), we have undertaken the identification of the molecules associated with the ligand binding unit and its associated subunit, gamma-chain, in a monocyte cell line, U937. Comparison of the pattern of tyrosine-phosphorylated proteins that coprecipitate with anti-Fc gamma RI or anti-gamma-chain Abs after Fc gamma RI clustering suggests that, like other receptor systems, the different units of the receptor associate or recruit different elements of the signaling pathway. Syk associates preferentially with the gamma-chain subunit and not with Fc gamma RI itself. This association is dependent on receptor clustering and correlates with gamma-chain phosphorylation. The Src kinase Lyn is also part of the receptor complex. Lyn associates with both units of the receptor, and this association is independent of receptor engagement; however, the level of tyrosine phosphorylation of the kinase increases after Fc gamma RI clustering. Association of a 35-kDa phosphoprotein with the binding unit was also observed after receptor clustering. We further found that after Fc gamma RI clustering, tyrosine-phosphorylated Syk associates with Lyn. These data suggest that several levels of interaction occur between these molecules or that different pools of tyrosine kinases become activated after Fc gamma RI clustering.

Antigen-Antibody Complex↗
PubMed1997

Short-term bladder-wall response to implantation of microstimulators.

This study examined the histological response of the bladder wall serosa to the implantation of wireless microstimulators secured with a single polypropylene suture. Two to three microstimulators were implanted in each of three casts for an eight week implantation period to allow sufficient time for a bladder-wall injury-response to develop. Gross observation revealed encapsulation of the microstimulators with no perforation to the bladder lumen or migration from the bladder wall. Histological evaluation confirmed that all the microstimutators were encapsulated with a thin connective tissue sheath and a thickened subserosal layer. There was no remarkable difference in tissue morphology compared with normal bladder wall sections for five of seven stimulators. Two microstimulators in one cat revealed a moderate to severe inflammatory response confined to a small area around the stimulator. In a second cat, a suture extended through the bladder wall. The microstimulators were observed with a scanning electron microscope after explantation. The electrode surfaces, bonding interface between silicon and glass and insulating films that were exposed to biological fluids were carefully inspected. All these observations indicate that the glass capsule reliably protected the sealed cavity of the microstimulators from moisture. These results indicate the microstimulator should be considered for further studies such as effects of stimulation and long-term implantation.

Animals↗
PubMed1997

A sublethal dose of LPS to pregnant rats induces TNF-alpha tolerance in their 0-day-old offspring.

The newborn has high mortality in septic shock. Induction of endotoxin tolerance may prevent endotoxic shock in the newborn. The present study showed that a small dose of Salmonella enteritidis lipopolysaccharide (S. ent. LPS), Rc mutant Escherichia coli lipopolysaccharide (J5 LPS), or tumor necrosis factor-alpha (TNF-alpha) given to pregnant rats on the 19th day of gestation induced endotoxin tolerance in their 0-day-old offspring. S. ent. LPS or J5 LPS injected into pregnant rats increased plasma endotoxin-like activity in dams, although not in their fetuses, and increased plasma TNF-alpha concentration in both dams and their fetuses. The endotoxin-tolerant newborn rats were also resistant to TNF-alpha. In those newborn rats, an LPS injection increased plasma TNF-alpha concentration and liver TNF-alpha mRNA abundance. These experiments showed that the endotoxin tolerance could be due to TNF-alpha tolerance. In conclusion, prenatal treatment of dams with a small dose of S. ent. LPS, J5 LPS, or TNF-alpha was beneficial in preventing endotoxic shock in the newborn.

Abortion, Veterinary↗