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Biomedical subjects

V Richardson

Publications and source records attributed to V Richardson.

At least 19 recordsLinked to original sources
PubMed1997

Migration responses of human monocytic cell lines to alpha- and beta-chemokines.

The beta-chemokines monocyte chemotactic protein 1 (MCP-1), macrophage inflammatory protein 1 alpha (MIP-1alpha), MIP-1beta and regulated on activation, normal T cells, expressed and secreted (RANTES) induced the in vitro migration of the monocytic cell line MonoMac-6. MCP-1 exhibits the most potent chemotactic effect on this cell line while MIP-1alpha, RANTES and to a lesser extent MIP-1beta were more moderate inducers of cell migration. MonoMac-6 migration in response to chemokines was shown to be a chemotactic and not a chemokinetic response, which was inhibited by pertussis and cholera toxins suggesting a role for G proteins in chemokine receptor-mediated signalling in these cells; chemotaxis of MonoMac-6 cells in response to MCP-1 was abrogated by the addition of anti-MCP-1 antibody. The response of MonoMac-6 cells to the alpha-chemokines IL-8, IP-10, growth-related peptide (Gro) alpha and MIP-2beta was substantially weaker than to the beta-chemokines. MCP-1 caused an alteration in cellular morphology by increasing ruffling at the cell membrane and the number of cells exhibiting extended pseudopodia. The chemotactic response of MonoMac-6 cells to beta-chemokines was compared with less well-differentiated myelomonocytic cell lines. THP-1 showed a similar, but weaker response to the beta-chemokines while both HL60 and U937 failed to respond to any member of this subfamily when tested under the same conditions. These results suggest that the differentiation status of cells of monocytic lineage may affect their response to beta-chemokines.

Cell Line↗
PubMed1997

The inability of cells to grow in low iron correlates with increasing activity of their iron regulatory protein (IRP).

We studied the factors that determine the differing growth requirements of low-iron-tolerant (LIT) versus high-iron-dependent (HID) cells for extracellular nontransferrin iron. The growth of LIT cells HeLa and THP-1, when transferred from transferrin (5 micrograms/ml) medium into low-iron (5 microM ferric citrate) medium, was not significantly affected while HID cells Jiyoye and K562 showed nearly no growth. HeLa and THP-1 cells, as well as Jiyoye and K562 cells, do not produce transferrin in sufficient amounts to support their growth in low-iron medium. Surprisingly, similar rates of iron uptake in low-iron medium (0.033 and 0.032 nmol Fe/min and 10(6) cells) were found for LIT cells HeLa and HID cells K562. Furthermore, the intracellular iron level (4.64 nmol/10(6) cells) of HeLa cells grown in low-iron medium was much higher than iron levels (0.15 or 0.20 nmol/10(6) cells) of HeLa or K562 cells grown in transferrin medium. We demonstrated that the activity (ratio activated/total) of the iron regulatory protein (IRP) in HID cells Jiyoye and K562 increased more than twofold (from 0.32 to 0.79 and from 0.47 to 1.12, respectively) within 48 h after their transfer into low-iron medium. In the case of LIT cells HeLa and THP-1, IRP activity stayed at similar or slightly decreased levels (0.86-0.73 and 0.58-0.55, respectively). Addition of iron chelator deferoxamine (50 microM, i.e., about half-maximal growth-inhibitory dose) resulted in significantly increased activity of IRP also in HeLa and THP-1 cells. We hypothesize that the relatively higher bioavailability of nontransferrin iron in LIT cells, over that in HID cells, determines the differing responses observed under low-iron conditions.

Biological Transport↗
PubMed1996

Vitamin B12 levels in human milk during the first nine months of lactation.

Vitamin B12 concentration was measured by competitive binding radioassay in 48 samples of human milk from healthy mothers eating unrestricted diets. Specimens were collected 1-35 weeks after full-term delivery and were subjected to proteolytic digestion before radioassay in order to destroy binding proteins. The distribution of the results was skewed, but the distribution of the logged values was not significantly different from normal. The geometric mean vitamin B12 level remained almost unchanged during the first 12 weeks postpartum (261-297 pmol/l) and then declined to a low of 139 pmol/l at 27-35 weeks. A significant (P = 0.033) decline in vitamin B12 concentration between 6-12 weeks and 19-25 weeks postpartum was observed.

Animals↗
PubMed1995

Social worker preparedness for retirement: gender and ethnic considerations.

A systematic, comprehensive analysis of preretirement attitudes and planning among social workers is clearly needed. This article describes research to examine the extent to which social workers adequately prepare for retirement. The analysis established controls for gender and ethnicity, specifically for African American, Puerto Rican, and white social workers, because earlier research indicates that these variables significantly affect how much and how well professionals prepare for retirement. Based on the findings, recommendations and a call for action are provided that will help social workers prepare better before they retire and struggle less during retirement. The need for social workers to conceptualize retirement as a process that has several stages is stressed.

Adult↗
PubMed1992

Retirement intentions among black professionals: implications for practice with older black adults.

This study examined the preretirement intentions of black professionals. The sample consisted of 234 blacks and was stratified by gender, age, and professional status. Based on a model developed for predicting the retirement intentions and attitudes of a sample of white professionals, six categories of independent variables (sociocultural, work history, alienation, leisure and social activities, financial planning, and plans for retirement life) were included in the analysis. Professionals who were highly committed to their work, had few financial investments, and socialized primarily with co-workers tended to avoid planning for retirement. These results have important implications for practitioners concerned with more effectively meeting the preretirement and retirement needs of older black adults.

Adult↗
PubMed1992

Cardiac tamponade from a fine silastic central venous catheter in a premature infant.

A 790 g infant developed cardiac tamponade 17 h after starting parenteral nutrition through a fine silastic catheter, the tip of which was accidentally positioned against the wall of the right atrium. Cold light examination suggested the diagnosis and pericardial aspiration of clear fluid with a high glucose content restored the circulation.

Cardiac Tamponade↗
PubMed1991

The IgE and IgG subclass antibody response to foods in babies during the first year of life and their relationship to feeding regimen and the development of food allergy.

This follow-up study of 191 babies investigated the development of food allergy in an unselected population and its relationship to total and antigen-specific IgE and IgG subclass levels. Sensitization to egg, as indicated by a positive skin test or RAST, was found in 5% of 1-year-old babies, but none of the babies in this series fulfilled the clinical criteria for immediate-type milk allergy. For both bovine casein (CAS) and egg albumin, the IgG response was largely restricted to IgG1 in contrast to the predominant IgG4 response to these antigens that is found in adults. The level of IgG4, but not IgG1, antibody to CAS and ovalbumin (OV) was lower in some of the babies compared with that of their mothers (N = 166; p less than 0.05, Student's paired t test). However, there was no difference in the total serum IgG subclass levels between mothers and babies. These results demonstrate that, in the population of babies studied, (1) type I hypersensitivity to egg occurred in 5% of 1-year-old babies, (2) the predominant IgG subclass of antibodies to CAS and OV in babies is IgG1, and (3) in the 22% of babies, there was substantially (greater than 1000-fold) less IgG4 antibody to CAS and OV than in their mothers, suggesting specific exclusion of some IgG4 antibodies.

Antibody Specificity↗
PubMed1991

Adjustment to retirement: continuity vs. discontinuity.

This research examines gender differences in adjustment to retirement during the first year of retirement. It identifies differences in patterns of adjustment and differences in the discriminating variables that predict these patterns. The study was longitudinal in design and included a pretest interview of 250 people at the time of retirement, a posttest interview of 242 retirees six months after retirement, and a one-year follow-up of 222 completed by mail. A significant main effect for time was found for all three adjustment variables, with well-being declining at the six-month interval. A discriminant analysis of three types of adjustment groups revealed that responses to retirement varies depending on several factors. The findings suggest the need for a dynamic view of continuity theory.

Aged↗
PubMed1989

Retirement financial planning among black professionals.

The extent and patterns of financial planning among 234 black professionals was compared with those of white professionals. The data revealed similar expectations of continued income, supplementing finances by working in another occupation, pension income, and dependency on spouses for income. Although they invested less in stocks and bonds and bank certificates, income and age were the most significant predictors of financial planning.

Adult↗
PubMed1984

Clinical and chemical assessment of thyroid function during therapy with amiodarone.

Clinical and chemical variables of thyroid function were studied in 26 patients with symptomatic ventricular tachyarrhythmias before and during long-term oral treatment with amiodarone. The mean (+/-SEM) pretreatment thyroxine (T4) level in the 26 patients was 7.32 +/- 0.33 micrograms/dL, and increased notably to 10.15 +/- 0.47 micrograms/dL by 30 to 120 days after treatment. The free thyroxine index (FT4I) was also notably elevated. Clinical hyperthyroidism or goiter did not develop, but clinical hypothyroidism occurred in four patients during and in one patient after discontinuation of amiodarone treatment. Notable titers of antithyroid antibodies were found in the serum of two of the five and a family history of thyroid disease was present in three of the five hypothyroid patients. An elevation of both the T4 level and the FT4I above the normal range is an expected finding in patients receiving amiodarone and does not by itself indicate hyperthyroidism. Patients with positive antithyroid antibodies or a family history of thyroid disease prior to treatment with amiodarone may be at an increased risk of hypothyroidism developing when treated with this drug.

Adult↗
PubMed1983

Projective assessment of the relationships between the salience of death, religion, and age among adults in America.

The relationships between age, religious orientation, and perception of death are investigated utilizing a sample of 1428 respondents randomly selected from two larger representative national samples. Although a statistically significant relationship is found between religion and perception of death, when age is introduced as a control the relationship remains only among young adults. The finding that religion mitigates concerns about death concurs with results found in previous studies. The data relative to young adults, however, suggest the need for a broader conceptualization of the relationship between death anxiety and religion, which incorporates developmental influences over the adult life cycle.

Adult↗