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Biomedical subjects

J Riggs

Publications and source records attributed to J Riggs.

17 recordsLinked to original sources
PubMed2000

Chlorhexidine lavage in the treatment of experimental intra-abdominal infection.

HYPOTHESIS: Closed postoperative peritoneal lavage (CPPL) with chlorhexidine gluconate reduces the number of intraperitoneal bacteria and improves the outcome of intra-abdominal infection. DESIGN: Laboratory animal trial. INTERVENTIONS: Intra-abdominal infection was produced in mice by the cecal ligation and puncture technique. After 16 to 18 hours, the animals underwent relaparotomy and placement of an intra-abdominal catheter for CPPL. In the first experiment animals were randomly divided into 4 groups: no lavage (served as a control), CPPL with chlorhexidine. CPPL with cefoxitin, and CPPL with lactated Ringer solution (LR). Lavage was continued intermittently every 8 hours for 24 hours. All animals received systemic cefoxitin every 8 hours for 7 days. Mortality was recorded every 8 hours for 10 days. In the second experiment, animals were divided into 3 groups: no lavage (served as a control), CPPL with chlorhexidine, and CPPL with LR. Lavage was continued intermittently every 8 hours for 24 hours. The animals were killed 48 hours after reoperation. Bacterial counts from peritoneal fluid and biopsy specimens, as well as peritoneal white blood cell counts, were measured before and after lavage. RESULTS: Closed postoperative peritoncal lavage with chlorhexidine reduced mortality from 71% in a control group to 37% (P = .003). There was no survival benefit in either the CPPL with cefoxitin (91% mortality) (P = .14) or CPPL with LR groups (90% mortality) (P = .17). The statistically significant findings of analysis of variance evaluation demonstrated a decrease in bacterial counts after cecal excision in all 3 groups. There was a greater reduction in bacterial counts in the chlorhexidine group compared with the control group (P<.05). Bacterial counts decreased in peritoneal fluid, as well as in tissue biopsy specimens, after cecal excision. White blood cell counts significantly decreased after cecal excision in all 3 groups. There was no difference in white blood cell counts between the groups. Correlation analyses demonstrated weak interaction between bacterial and white blood cell counts before or after treatment in all the groups. Pearson r ranged from -0.37 to +0.35, none of which were statistically significant. CONCLUSIONS: In our experiments chlorhexidine lavage resulted in a 50% reduction in mortality and a significant reduction in bacterial counts compared with the control group. There was no survival benefit from lavage with either cefoxitin or LR. There was no reduction in bacterial counts in the LR group relative to the control group. Thus, the survival benefit and the reduction in bacterial numbers are attributed to the antibacterial properties of chlorhexidine rather than to the mechanical washing of the abdominal cavity. Closed postoperative peritoneal lavage with 0.05% chlorhexidine gluconate might be useful in the multimodal treatment of intra-abdominal infection.

Animals↗
PubMed2000

DBA/2J (Mls-1a) B-cell differentiation in BALB.xid recipients.

Studies of superantigens (SAg) have focused primarily on their impact on CD4+ T cells, largely bypassing the impact of the sequelae of this interaction upon the antigen-presenting cell (APC). Sequelae of SAg-induced CD4+ T-cell activation include the 'bathing' of the SAg-presenting cell with cytokines that promote the differentiation of the APC. In this report, the SAg-induced differentiation of Mls+ DBA/2J B cells was studied in vivo by their transplantation into B-cell-defective BALB.xid recipients. Rapid, high-level serum immunoglobulin M (IgM) production was noted shortly after transfer, disappearing by 3 weeks. Donor B cells, as evidenced after their chemical and genetic impairment and by the use of an IgM allotype-disparate donor-recipient combination, contributed to this transient IgM production. These results clarify a discrepancy in the literature regarding donor B-cell contribution to IgM production and illustrate a model system to utilize SAg to study B-lymphocyte diversity.

Adoptive Transfer↗
PubMed1998

Increased serum IgG1 levels and reduced numbers of B-1 B cells in DBA/2J mice.

B-cell heterogeneity studies have historically focused upon BALB/c mice and their derivatives. In contrast, the B cells of DBA/2J mice, a prototype strain for the study of the endogenous minor lymphocyte stimulatory (Mls) viral superantigen Mls-1a, have not been extensively investigated. DBA/2J B cells, by functioning as Mls-1a antigen-presenting cells, influence their own differentiation and diversity by inducing the proliferation and differentiation of specific CD4 T-cell subsets. In this report, the B cells of DBA/2J and BALB/c mice were compared for their ability to restore B-cell function in severe combined immunodeficient (SCID) recipients. Although spleen and bone marrow cells from these strains exhibited similar restoration of serum IgM production, the transfer of DBA/2J B cells into SCID mice led to greater IgG1 production. The peritoneal cells of DBA/2J mice consisted of a lower percentage of B-1 B cells and were less capable of restoring B-cell function after transfer into SCID recipients. These differences are discussed with respect to the possible role of viral superantigens in influencing B-lymphocyte diversity.

Adoptive Transfer↗
PubMed1998

Declines in patient volume: an obstetrics and gynecology teaching program's response.

Historically, University teaching hospitals have been the primary providers of health care to the indigent population. With the advent of managed health-care plans, the university hospitals have seen a rapid decline in their obstetrical patient populations. This decrease is reflected in the numbers of deliveries and gynecological surgeries. From 1990 to 1995, these changes resulted in a significant decline in deliveries at our hospital, the Lyndon B. Johnson General Hospital. To reverse this ominous trend, we instituted a variety of changes resulting in a more patient-centered system and found an improvement in the numbers of obstetrical patients. In the following report, we describe these changes and the subsequent outcome.

Delivery, Obstetric↗
PubMed1997

Recipient age determines the success of intraperitoneal transplantation of peritoneal cavity B cells.

In vivo studies of lymphocyte biology have used intravenous (i.v.) injection as the primary mode of cell transfer, a protocol consistent with the anatomic distribution of most lymphocytes. However, for study of peritoneal cavity B cells, i.v. injection does not correlate with anatomical localization. This report describes the restoration of B-cell function in B lymphocyte-defective X-chromosome-linked immune-defective (XID) mice after intraperitoneal transfer of immunoglobulin heavy chain (Igh)-disparate peritoneal cavity (PerC) cells. In contrast to i.v. transfer, intraperitoneal (i.p.) transfer restored B-cell function in young, but not adult (> 8 weeks), XID mice. When host and donor Igh allotype matched, PerC B-cell engraftment was noted in older recipients; this reconstitution however, was also age-dependent. Migration from the peritoneum to systemic circulation was necessary for serum IgM production as shown by the presence of donor antibody-secreting cells in the host spleen. Host lymphocytes also influenced the success of i.p. transplantation as severe combined immune-deficient mice, regardless of age, exhibited donor serum IgM production. Recipient age, Igh allotype, and immune-deficiency were found to have an impact on the ability of i.p.-transferred PerC B cells to restore B-cell function in XID mice.

Aging↗
PubMed1996

Ability of spleen, peritoneal cavity, and lymph node B cells to reconstitute serum immunoglobulin in SCID mice.

The impact of intrinsic B lymphocyte heterogeneity and of microenvironmental influences on serum immunoglobulin production by B cells was examined by intravenous (i.v.) and intraperitoneal (i.p.) transfer of BALB/c and BALB.xid (X-chromosome-linked immunedefective; XID) lymph node (LN), splenic (SP) and peritoneal cavity (PerC) cells into severe-combined immune-defective (SCID) mice. The results indicate that each B-cell source restores all immunoglobulin classes within 5 weeks of transfer, the rates for each isotype, however, differ between the B-cell sources. Serum IgM levels were restored most rapidly by PerC cell transfer, followed by SP and LN cell transfer. In addition, normal immunoglobulin levels were reached in the absence of complete lymphoid reconstitution. Serum immunoglobulin phenotypes characteristic of the donor strain, e.g. reduced IgM and IgG3 production by XID B cells, were maintained after transfer into the SCID recipient. Microenvironmental influences were indicated by reduced immunoglobulin production after i.p. transfer and after i.v. transfer into irradiated SCID recipients. The data show that both B-cell type and microenvironment play significant roles in generating the heterogeneous pool of B cells required for humoral immunity.

Animals↗
PubMed1994

Rapid restoration of B-cell function in XID mice by intravenous transfer of peritoneal cavity B cells.

The primary method employed to correct immune deficiency is bone marrow transfer. Depending upon the exact nature of the immune deficiency, however, alternative cell sources may be used to provide a more rapid reconstitution of immune function. In this report, peritoneal cavity (PerC) B cells are shown to be effective in the rapid emendation of the B-cell defect exhibited by XID mice. Restoration of normal numbers of splenic IgM antibody-secreting cells (ASC) and serum IgM levels were observed 4 and 7 days, respectively, after the i.v. transfer of 3 x 10(6) PerC. This regimen also restored responsiveness to thymus-independent type 2 (TI-2) antigens in XID recipients. Transfer of 30 x 10(6) spleen (SP) cells restored these functions in XID recipients but at a considerably slower rate. The data indicate that introducing a small number of PerC B cells into systemic circulation results in the rapid restoration of serum IgM levels in unirradiated XID mice.

Animals↗
PubMed1991

Age and gender differences in beliefs about personal power and injustice.

College students and community-dwelling older adults were compared on Injustice and Personal Power scales and measures of religiosity. "Personal Power" scores varied significantly as a function of age and gender. These differences were attributable to a significantly lower belief in "Personal Power" for the group of older women. As predicted, "Injustice" scores were significantly higher for women than for men, reflecting a greater belief that conditions can be unjust. No significant difference between older and younger adults on "Injustice" scores was obtained. Significant positive correlations between measures of religiosity and "Injustice" scores were obtained, while religiosity was not significantly correlated with "Personal Power." This pattern of results suggests that there is value in utilizing separate measures of "Injustice" and "Personal Power" scores. Suggestions are made for examining further the complex relationship among demographic variables, belief in a just world, and measures of religiosity.

Adult↗
PubMed1987

Sexual practices and risk of infection by the human immunodeficiency virus. The San Francisco Men's Health Study.

The San Francisco Men's Health Study is a prospective study of the epidemiology and natural history of the acquired immunodeficiency syndrome in a cohort of 1034 single men, 25 to 54 years of age, recruited by multistage probability sampling. At entry, June 1984 through January 1985, the seropositivity rate for human immunodeficiency virus (HIV) infection among homosexual/bisexual study participants was 48.5%. No heterosexual participants were HIV seropositive. Among homosexual/bisexual men reporting no male sexual partners in the two years before entry into the study, seropositivity was 17.6%. For those reporting more than 50 partners, seropositivity was 70.8%. Only receptive anal/genital contact had a significantly elevated risk of HIV infection. Douching was the only ancillary sexual practice that contributed significantly to risk of infection.

Acquired Immunodeficiency Syndrome↗
PubMed1981

Fibronectin production by human mammary cells.

Human mammary cells were examined for the presence of the high-molecular-weight surface glycoprotein fibronectin. Early passage mammary epithelial cell and fibroblast cultures from both carcinomas and normal tissues were tested for the presence of cell-associated fibronectin by immunofluorescence microscopy and for the synthesis and secretion of fibronectin by specific immunoprecipitation of metabolically labeled protein. In vivo frozen sections of primary carcinomas and normal tissues were tested for the localization of fibronectin by immunofluorescence microscopy. In contrast to the extensive fibrillar networks of fibronectin found in the fibroblast cultures, the epithelial cell cultures from both tissue sources displayed a pattern of cell-associated fibronectin characterized by powdery, punctate staining. However, the cultured epithelial cells, as well as the fibroblasts, secreted large quantities of fibronectin into the medium. Putative myoepithelial cells also displayed extensive fibrillar networks of fibronectin. The difference in cell-associated fibronectin distribution between the epithelial cells and the fibroblasts and putative myoepithelial cells provided a simple means of quantitating stromal and myoepithelial cell contamination of the mammary epithelial cells in culture. In vivo, normal tissues showed fibronectin primarily localized in the basement membrane surrounding the epithelial cells and in the stroma. Most primary carcinomas displayed powdery, punctate staining on the epithelial cells in addition to the fibronectin present in the surrounding stroma.

Basement Membrane↗
PubMed1975

Studies on morphological transformation of BALB/3T3-derived clones by murine leukemia virus.

We have described a cell line, UC1-B, derived spontaneously from BALB/3T3 mouse embryo cells, which, unlike the standard BALB/3T3, are morphologically transformed and produce bizarre viral forms in response to murine leukemia virus. Although UC1-B and BALB/3T3 are morphologically similar, and both form contact-inhibited monolayers at confluence, the UC1-B cells are partially transformed because: they grow to a slightly higher saturation density than 3T3 cells, they grow in medium lacking serum growth factors, and they produce tumors in mice. Another clone, 12A-3, derived from BALB/3T3, also transforms and produces bizarre viral forms after infection with murine leukemia virus. Unlike UC1-B cells, the 12A3-8 cells are identical in growth properties to BALB/3T3; therefore, a partially altered morphology is not required for the induction of transformation by murine leukemia virus.

Animals↗