Biomedical subjects

J L Bryant

Publications and source records attributed to J L Bryant.

46 records · Page 3Linked to original sources

PubMed1992

Progressive glomerulosclerosis and enhanced renal accumulation of basement membrane components in mice transgenic for human immunodeficiency virus type 1 genes.

Patients infected with human immunodeficiency virus type 1 (HIV-1) develop a renal syndrome characterized by proteinuria, renal failure, and focal segmental glomerulosclerosis. By using a noninfectious HIV-1 DNA construct lacking the gag and pol genes, three transgenic mouse lines have been generated that develop a syndrome remarkably similar to the human disease. In the present study, we have characterized in detail one of these lines, Tg26. In Tg26 mice, proteinuria was detectable at approximately 24 days of age, followed by severe nephrotic syndrome and rapid progression to end-stage renal failure. Renal histology showed focal segmental glomerulosclerosis and microcystic tubular dilatation. Indirect immunofluorescence studies demonstrated increased accumulation of the basement membrane components laminin, collagen type IV, and heparan sulfate proteoglycan. The viral protein Rev was present in sclerotic glomeruli. Northern blot analysis of total renal RNA showed expression of viral genes prior to the appearance of histologic renal disease, with greatly diminished viral gene expression late in the disease course. Kidneys from transgenic mice expressed increased steady-state levels of collagen alpha 1(IV) mRNA when glomerulosclerosis was present. We conclude that the presence of HIV-1 genes is associated with progressive renal dysfunction and glomerulosclerosis in transgenic mice.

Animals↗

PubMed1991

Granulocytopenia in cancer patients treated in a phase I trial with recombinant human tumor necrosis factor.

We have examined the effect of recombinant human tumor necrosis factor (TNF) upon granulocyte kinetics in cancer patients in a phase I clinical trial. TNF was given to each patient intravenously over 2 h at varying doses. A marked drop in the total white blood cell count, absolute polymorphonuclear leukocyte (PMN) count, and absolute monocyte count occurred reproducibly at 30 min after TNF initiation. Also noted was a drop in the absolute lymphocyte and eosinophil counts, both of which reached their nadir at approximately 4 h. A marked increase in immature PMN leukocytes (bands) was noted beginning at 1 h. These changes were statistically significant. Statistically significant increases in hemoglobin and hematocrit occurred at the 30 min time point but subsequently decreased to approximately 90% of pretreatment baseline. Additionally, the platelet count decreased, reaching its nadir approximately 6 h after TNF initiation. In four serial studies in patients on the highest dose of TNF, the granulocyte adhesion protein CD11b was shown to increase on the surface of the PMN leukocytes by as early as 7-15 min after initiation of TNF infusion. In each of these, expression of CD11b antigen increased prior to the disappearance of PMN leukocytes from the peripheral circulation. A similar finding was obtained for monocytes. This work indicates that within 30 min of intravenous infusion of TNF, mature granulocytes and monocytes have left the peripheral circulation. This is followed by an apparent bone marrow response indicated by an outpouring of bands. The initial granulocyte and monocyte emigration from the peripheral circulation is preceded at highest-dose TNF by increased cell surface expression of CD11b for both cell types, suggesting a causal relationship between these temporally linked events.

Agranulocytosis↗

PubMed1989

Development of a direct-binding enzyme-linked immunosorbent assay as an alternate assay for anti-hepatitis B core.

Anti-hepatitis B core (anti-HBc) screening is now used in some countries as a surrogate test to reduce the incidence of posttransfusion non-A, non-B hepatitis. The purpose of this study was to develop and standardize an alternate assay, for the detection of anti-HBc, based on a direct-binding enzyme-linked immunosorbent assay (db-ELISA). Microtiter plates were coated with recombinant DNA hepatitis B core antigen. Patient antibody was detected spectrophotometrically using a goat, anti-human immunoglobulin conjugated with horseradish peroxidase. The db-ELISA was compared to a standard competitive-binding ELISA (cb-ELISA). A competitive-binding radioimmunoassay (cb-RIA) was used as the reference assay for this study. The specificity of the cb-ELISA was 50% and the positive predictive value was 64% when compared to the cb-RIA. The specificity and positive predictive value of the db-ELISA were both 97% when compared to the cb-RIA. Based on titration studies, the sensitivity of the db-ELISA is at least equal to the cb-RIA. Based on the data generated in this study, the db-ELISA appears to be an acceptable screening test for anti-HBc.

Enzyme-Linked Immunosorbent Assay↗

PubMed1984

DNA injection proteins are targets of acridine-sensitized photoinactivation of bacteriophage P22.

Viruses and other nucleoprotein complexes are inactivated on exposure to white light in the presence of acridine and related dyes. The mechanism is thought to involve generation of singlet oxygen or related species, but the actual molecular targets of the inactivating event have not been well defined. We have re-examined the mechanism of dye-sensitized photoinactivation taking advantage of the well characterized bacteriophage P22. Though the inactivated phage absorb to their host cells, the cells are not killed and genetic markers cannot be rescued from the inactivated phage. These observations indicate that the chromosome is not injected into the host cell. However, the DNA of the damaged particles shows no evidence of double-stranded breaks or crosslinking. The DNA injection process of P22 requires three particle-associated proteins, the products of genes 7, 16 and 20. Gp16, which can act in trans during injection, is inactivated in the killed particles. Sodium dodecyl sulfate/polyacrylamide gel analysis reveals that gp16, gp7 and gp20 are progressively covalently damaged during photoinactivation. However, this damage does not occur in particles lacking DNA, indicating that it is DNA-mediated. Similar findings were obtained with acridine orange, acridine yellow, proflavin and acriflavin. These results indicate that the actual targets for inactivation are the DNA injection proteins, and that the lethal events represent absorption of photons by acridine molecules stacked in a region of DNA closely associated with the injection proteins.

Acridines↗

PubMed1983

Campylobacter jejuni isolated from patas monkeys with diarrhea.

Campylobacter jejuni was isolated from 11 (46%) of 24 patas monkeys with chronic diarrhea. Eight of these 11 (73%) monkey were characterized clinically by mucohemorrhagic diarrhea for periods up to a month followed by loose, semi-formed feces for a 12-month period. Half of the monkeys were treated with erythromycin for 10 days and the other half with tetracycline for 10 days, with all responding to treatment. Despite treatment, all monkeys again had an outbreak of mucohemorrhagic diarrhea. Biopsy specimens were taken from all eight monkeys over a period of 3 months. The clinical signs, treatment, and the gross and microscopic lesions seen in these monkeys were similar to those reported in humans and animals infected with Campylobacter jejuni.

Animals↗

PubMedDate not supplied

Volumetric flow in the umbilical artery: normative data.

OBJECTIVE: Provide normative data for the volumetric blood flow (cc/min and cc/min/kg) in the umbilical artery. METHODS: Flow was determined from an umbilical artery in 252 normal obstetrical patients from 18-40 weeks' gestation utilizing pulsed Doppler and color flow Doppler with an angle of insonation of 30-60 degrees. Simultaneous velocimetry studies (S/D ratio, resistance and pulsatility indices), fetal biometry, and an anatomic survey were obtained to further define the normal population. RESULTS: There was a steady increase in the flow (cc/min) in the umbilical artery as pregnancy progressed. Flow/kg showed a steady decline as fetal weight increased. Umbilical artery diameter increased until reaching a plateau at 32-34 weeks. Velocimetric results were consistent with known data. CONCLUSIONS: Volumetric blood flow in the umbilical artery can be determined with relative ease and normative data from 18-40 weeks is presented for the first time.

Adult↗

PubMedDate not supplied

AIDS-related Kaposi's sarcoma patients with visceral manifestations. Response to human chorionic gonadotropin preparations.

OBJECTIVE: In vitro cell culture studies and a murine model for human Kaposi's sarcoma (KS) have shown that human chorionic gonadotropin (hCG)-associated factor (HAF) isolated from commercial hCG preparations has antiproliferative and cell killing effects on neoplastic KS cells, without toxic effects on normal endothelial cells and lymphocytes. These findings prompted preliminary study of hCG preparations for patients with early-stage KS with skin lesions only and no known visceral involvement. Complete or partial regression of the skin lesions occurred after intralesional injections of hCG (hCG-Pregnyl, hCG-APL). The current study sought to extend these early observations to evaluation of the safety of hCG in acquired immunodeficiency syndrome (AIDS) KS patients with aggressive disease and visceral involvement. These patients present in a more advanced stage of the disease that is coupled with serious immunodeficiency. They commonly respond poorly to conventional chemotherapy and have a reduced median life expectancy of only 4 to 9 months. STUDY DESIGN/METHODS: After approval by the local institutional review boards, 13 patients with advanced AIDS-KS gave informed consent and were treated with hCG preparations. These hCG preparations are known to have antiproliferative activity in laboratory tests. Patients were monitored for tumor size by clinical evaluation, ultrasonography, radiography, respiratory functions, and endoscopic examination. Histologic examinations of biopsied tissues were used for studies of apoptosis using in situ hybridization techniques. The patients were also monitored for CD4+ T-cell numbers and human immunodeficiency virus type 1 (HIV-1) plasma viral load according to common clinical practice. RESULTS: Thirteen patients with advanced AIDS-KS and visceral KS were treated with hCG. Five of 13 (38%) patients had dramatic responses to therapy, and overall tolerance to the drug was excellent for all patients. Some hCG preparations also showed beneficial effects against HIV-associated markers. An accompanying decrease in viral load (plasma HIV-1 RNA) was observed in one patient, a dramatic increase in CD4+ cells occurred in another, and significant weight gain was seen in seven patients. CONCLUSIONS: These clinical observations suggest that patients with aggressive visceral forms of KS, usually indicative of an extremely poor prognosis and poor response to combined chemotherapy, can benefit from this new therapeutic approach. In some patients, these preparations also induce several other beneficial effects, such as weight gain, reduction in HIV-1 RNA load, or increase in the CD4+ T-cell count. Additional controlled clinical trials comparing this new therapeutic option with standard cytotoxic chemotherapy are needed. These trials should be extended to patients with KS not related to HIV-1 infection. Because we showed elsewhere that pure hCG had no effect on KS, identification and subsequent clinical use of the active molecules in hCG preparations is urgently needed.

AIDS-Related Opportunistic Infections↗

PubMedDate not supplied

HIV-1 protease inhibitor ritonavir modulates susceptibility to apoptosis of uninfected T cells.

OBJECTIVE: Clinical experience with HIV-1 protease inhibitors (PIs) in the treatment of AIDS frequently has shown that increases in CD4+ T-cell counts can be independent of HIV-1 inhibition by these drugs. This disconnection between viral load and CD4 counts led us to investigate how the PI ritonavir directly affects leukocyte activation in vitro, using peripheral blood mononuclear cell (PBMC) fractions derived from normal donors. METHODS AND RESULTS: When uninfected PBMC cultures were treated for 72 hours with ritonavir at concentrations similar to or lower than that shown to be effective in vivo, an increase in cell viability was observed. The susceptibility of PBMCs to apoptosis was markedly decreased after ritonavir treatment and correlated with lower levels of caspase-1 expression, decreases in annexin V staining, and reduced caspase-3 activity. Induction in vitro of tumor necrosis factor (TNF) production by PBMCs and monocytes was inhibited by ritonavir in a time- and dose-dependent manner at nontoxic concentrations. CONCLUSION: Based on our data, we conclude that the HIV-1 PI ritonavir is an immune modulator that may affect leukocyte activation and apoptosis as an important part of its therapeutic benefit.

Annexin A5↗

PubMedDate not supplied

Neoplastic AIDS-associated Kaposi's sarcoma cell line KSY-1 cannot transdifferentiate into capillaries.

OBJECTIVE: Kaposi's sarcoma (KS) is an acquired immunodeficiency syndrome (AIDS)-defining neoplasm histologically characterized by proliferation of spindle cells, inflammatory cells, and abundant neovascularization. When the malignant cell line KSY-1 derived from an AIDS-KS tumor is transplanted subcutaneously into nude mice, prominent neovascular features develop. Using this mouse model of neoplastic KS, we set out to determine, using c-ets 1 markers specific for mouse or human tissues, whether vascular growth and inflammatory infiltrate induced by the transplanted KSY-1 cells is of host cell or transplant origin. STUDY DESIGN/METHODS: KS tumors were induced by subcutaneous inoculation of 5 x 10(6) KSY-1 cells/200 microL in immunodeficient mice, and species-specific mouse and human riboprobes of the c-ets 1 protooncogene were used for in situ hybridization to define cell of origin. RESULTS: Five different tumors were examined. Tissue sections from all cases were hybridized with radiolabeled riboprobes for the presence of both mouse and human c-ets 1 mRNA. Tumor cells were labeled with the human c-ets 1 probe, whereas neovascular and inflammatory tissues were of mouse origin. CONCLUSIONS: The finding that vascular but not tumor cells are of host origin supports the model of tumor-induced vascularization via a mechanism of tumor cell-derived cytokine-medicated pathogenesis.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

Foot care: focus on the elderly.

Problems in the foot develop as a result of the aging process or systemic disease. Common causes of pain and disability in the elderly are nail and skin problems, predominantly corns and calluses, along with circulatory and structural problems. Because patients with orthopaedic conditions may have preexisting foot problems, it is important for nurses to distinguish between minor foot problems that can easily be treated and more serious conditions that require referral to a specialist. This article discusses pathophysiology of the aging foot, a comprehensive foot assessment, common foot problems with nursing interventions, pressure relief and shoewear, and nurses' qualifications for providing foot and nail care.

Aged↗