Immunosuppressive properties of surfactant in alveolar macrophage NR8383.

OBJECTIVE: To evaluate the anti-inflammatory effects of exogenous surfactants and surfactant phospholipid without surfactant proteins (SP-A and SP-D) on the lipopolysaccharide- (LPS) stimulated rat alveolar macrophage (AM) cell line NR8383. METHODS: Exogenous surfactants (beractant, calfactant or colfosceril) and surfactant phospholipid (dipalmitoyl phosphatidylcholine, DPPC), standardized to phospholipid content of 25-1,000 microg/ml were incubated with LPS- (1 microg/ml) stimulated NR8383 AMs. RESULTS: TNF-alpha and IL-1beta secretion and nitric oxide (NO) formation following LPS stimulation were inhibited by treatment with surfactants or DPPC. Furthermore, LPS-dependent NO production and iNOS protein levels were significantly suppressed in cells pretreated for one hour with beractant compared to beractant added simultaneously with or following LPS. Additionally, LPS-stimulated oxidative burst, measured by flow cytometry, was significantly decreased by beractant. Finally, beractant inhibited the translocation of NF-kappaB from cytoplasmic into nuclear extract in LPS-stimulated NR8383 AMs. CONCLUSIONS: Exogenous surfactants and surfactant phospholipid inhibit secretion of proinflammatory cytokines and NO in NR8383 AMs. The inhibitory effects of beractant on oxygen radical and LPS-induced NO formation may result from unique mechanisms of decreasing cell signaling. The anti-inflammatory activity of surfactant products used in the treatment of neonatal respiratory distress syndrome (RDS) may depend upon the specific preparation or dose used.

Pregnancy and labor increase the capacity of human myometrial cells to secrete parathyroid hormone-related protein.

Parathyroid hormone-related protein (PTHrP), a oncofetal gene product possessing smooth muscle relaxant properties, has been found in rat and human uterine smooth muscle cells (USMC) where it is postulated to regulate myometrial tone and/or blood flow. Studies investigating the gestational regulation of PTHrP in human USMC have not been performed. This study was conducted to determine if pregnancy alters the capacity of USMC to secrete or respond to PTHrP. USMC cultures were established from 8 hysterectomy specimens (H) and 7 non-laboring (NP) and 5 laboring term pregnant uterine biopsies (LP). PTHrP secretion was measured at baseline and in response to TGF-beta1 using a immunoradiometric assay. The USMC response to PTHrP was assessed by incubating cultures with human (1-34)PTHrP and measuring cellular cAMP by radioimmunoassay. We found that cultures from the groups did not differ with respect to basal PTHrP secretion. TGF-beta1, on the other hand, produced dose-dependent increases in secreted PTHrP in each group such that LP>NP>H at 12 hrs and LP>NP and H 24 hrs. Maximal responses were found at 24 hrs in cells treated with 10 ng/ml TGF-beta1 (LP: 2034+/-366 vs NP: 1485+/-427; H: 1250+/-202 fmol/mg). Incubation of cultures with PTHrP produced dose-dependent increases in cAMP production, with 10(-7) M increasing levels by 64%. Neither pregnancy nor labor significantly affected the cAMP response. These findings indicate that the human myometrium has the capacity to increase PTHrP secretion during pregnancy and labor through a TGF-beta-dependent pathway. Such findings are consistent with a role of PTHrP in enhancing uterine blood flow.

Oxygen induces S-phase growth arrest and increases p53 and p21(WAF1/CIP1) expression in human bronchial smooth-muscle cells.

Hyperoxia increases free radical production, leading to DNA damage. Recent studies indicate that oxygen augments the expression of p53 and p21(WAF1/CIP1), and increases apoptotic labeling of airway epithelial cells. Similar changes in regulatory gene products have not been reported in other pulmonary cells, nor have these changes been investigated in conjunction with alterations in cell-cycle distribution. The present study was conducted to determine whether oxygen alters the expression of p53 and p21(WAF1/CIP1) in human bronchial smooth-muscle cells (BSMC). BSMC placed in room air (RA), 40% O(2), or 95% O(2) were examined for 3 d to determine cell number, thymidine incorporation, cell-cycle distribution, and lactate dehydrogenase release. Apoptosis was assessed through the terminal deoxynucleotidyl transferase-deoxyuridine triphosphate end-nick labeling (TUNEL) technique, and p53 and p21(WAF1/CIP1) protein levels were determined through enzyme-linked immunosorbent assay. Exposure of BSMC to 95% O(2) decreased proliferation and DNA synthesis within 24 h, and was accompanied by an increase in S-phase cells (72 h; RA: 12.9 +/- 4.6%, versus 95% O(2): 34.6 +/- 7.0%; P < 0.01). By comparison, exposure to 40% O(2) resulted in decreased proliferation at 48 h without significant alterations in cell-cycle distribution. Both p53 and p21(WAF1/CIP1) levels were increased by 95% O(2), with maximal differences noted at 24 and 48 h, respectively. All atmospheres showed < 8% cell death and few TUNEL-positive cells. Our results indicate that oxygen-mediated alterations in BSMC proliferation are time- and concentration-dependent. Furthermore, high oxygen levels induce S-phase arrest and increased expression of p53 and p21(WAF1/CIP1). Activation of these genes may prevent replication without inducing apoptosis to allow for the repair of oxidative damage.

The influence of hyperbaric oxygenation on leukocyte viability and surface protein expression.

Hyperbaric oxygenation was studied as a potential inducer of cell growth and differentiation in promyelocytic leukemic HL60 cells. We studied changes in HL60 cells exposed to hyperbaric oxygen, oxygen, or carbon dioxide for 72 h. The proliferation rate and viability of cells in the hyperbaric oxygenation groups were significantly lower (p < 0.05) than for the controls. While CD13 and CD38 were expressed less following hyperbaric treatment, CD11b, CD14, and CD16 showed an increase following hyperbaric treatment, and CD10, CD15, and HLADR showed no change. These results support previous studies which demonstrate the role of oxygen tension in the regulation of cell cycle and protein expression.

Inhibition of human transitional cell carcinoma in vitro proliferation by fluoroquinolone antibiotics.

PURPOSE: The in vitro effects of the fluoroquinolone antibiotics ciprofloxacin and ofloxacin upon 3 human transitional cell carcinoma cell lines were investigated at concentrations that are attainable in the urine of patients taking these drugs orally. MATERIALS AND METHODS: Cell lines TCCSUP, T24, and J82 were exposed in culture to either ciprofloxacin or ofloxacin at concentrations ranging from 0 to 800 micrograms./ml. and at durations ranging from 24 to 120 hours. Inhibition of proliferation and DNA synthesis were assessed via MTT and tritiated thymidine assays, respectively. RESULTS: From the MTT assay ciprofloxacin, at concentrations of 25 to 800 micrograms./ml., produced proliferation inhibition in the TCCSUP line ranging from 8.1% to 90.2% at 24 hours, 25.1% to 94.9% at 72 hours, and 53.8% to 96.9% at 120 hours. Inhibition of proliferation for the T24 line ranged from 8.0% to 85%, 31.5% to 96.5%, and 27.3% to 98.2%. Inhibition of proliferation of the J82 line ranged from 20.8% to 84.8%, 22.8% to 92.7%, and 37.4% to 97.1%. Inhibition of DNA synthesis (due to ciprofloxacin at the concentrations above) as measured by the tritiated thymidine assay was also significant for each of the 3 cell lines. Inhibition of proliferation and DNA synthesis due to ofloxacin was lower but not overall statistically different from that due to ciprofloxacin. In a separate experiment, enhanced cytotoxicity was observed at lower concentrations of ciprofloxacin when the initial media pH was approximated to 5.5. CONCLUSIONS: Ciprofloxacin and ofloxacin inhibit proliferation and DNA synthesis of these 3 human TCC lines in vitro. Inhibition occurred in a concentration- and time-dependent manner. The concentrations that were assessed are attainable in the urine of patients taking these agents orally.

Infection with the human immunodeficiency virus in prisoners: meeting the health care challenge.

The magnitude and the scope of health care problems posed by human prison inmates seropositive for the human immunodeficiency virus (HIV) are enormous. Prisoners represent a substantial proportion of HIV-infected individuals in North America. A high proportion of prisoners are intravenous drug users who often have not received appropriate health care or HIV-directed services prior to incarceration. Health care of HIV-seropositive prisoners and follow-up medical care after prison release has often been less than optimal. Among inmates at the prison facility in Rhode Island, 4% of the men and 12% of the women are HIV seropositive. The Brown University medical community, in conjunction with the Rhode Island Department of Health and Corrections, has developed an effective program for the health care of such prisoners, both during incarceration and after release from prison. Academic medical centers are uniquely poised to assume the leading role in meeting this obligation. We believe that this general approach, with region-specific modifications, may be effectively applied in many correctional institutions in North America.

Interleukin-6 is released in the cutaneous response to allergen challenge in atopic individuals.

The mechanisms responsible for cutaneous response to antigen are complex. Interleukin-1 (IL-1) and interleukin-6 (IL-6) are proinflammatory cytokines that share many properties. Previous studies with a blister-chamber model have demonstrated IL-1 to be produced in the cutaneous response to antigen. Since IL-2 production by activated T cells and IL-6 production by macrophages are both stimulated by IL-1, we hypothesized that IL-2 and IL-6 may be involved in the cutaneous late-phase response (LPR) to antigen. We examined antigen-challenged sites for IL-2 immunoreactivity (ELISA) but found no difference between antigen- and diluent-challenged skin sites (N = 4). Since IL-2 has been demonstrated to be produced in response to IL-1 and IL-1 activity has been demonstrated to be greatest between hours 10 and 12, we speculated that IL-2 might not be detected until after hour 12. We were unable to demonstrate any increase in IL-2 production, even by extending our studies to 24 hours in two subjects. Antigen-challenged, skin blister-chamber fluids from atopic subjects demonstrated the appearance of IL-6 (ELISA) in pooled samples representing hours 1 1/2, 3 1/2, 5 1/2, and 7, but not at diluent control sites (p less than 0.05; N = 6). IL-6 reached a median peak of 0.66 ng/ml at 3 1/2 hours. Median levels of IL-6 fell to baseline at 8 hours, followed by a second peak of 0.25 ng/ml at hour 10. Three distinct patterns of IL-6 release were noted: early release of IL-6 followed by a sustained slower rise that peaked at hour 9 before declining to baseline levels at 12 hours, early release of IL-6 followed by a fall to baseline levels at hours 7 to 9 with a second smaller peak at hours 9 to 11, and isolated early release of IL-6. Early IL-6 production correlated with late histamine production (R = 0.801; p = 0.06), and late IL-6 production correlated with eosinophil influx (R = 0.813; p = 0.05). The area of the LPR at skin test sites correlated with early IL-6 peak levels (R = 0.977; p = 0.004) and with total early IL-6 production (R = 0.885; p = 0.05), but not with late IL-6 production.(ABSTRACT TRUNCATED AT 400 WORDS)

Human T-lymphotropic virus type I (HTLV-I) and tropical spastic paraparesis or HTLV-I-associated myelopathy in Hawaii.

Tropical spastic paraparesis or human T-lymphotropic virus type I (HTLV-I)-associated myelopathy is a degenerative encephalomyelopathy with pyramidal tract dysfunction affecting the lower extremities. It is associated with HTLV-I infection and found primarily in the Caribbean region and in southwestern Japan. Five cases of tropical spastic paraparesis (or HTLV-I-associated myelopathy) in Hawaii are reported. All five patients were born in Hawaii; four are women. Each of the patients has parents who were from HTLV-I-endemic areas of Japan. Two of these patients had serum antibodies to HTLV-I. Five of six of the spouses and children of the seropositive patients were also seropositive. Viral cultures of lymphocytes from both seropositive patients and two of the three seropositive children were positive for HTLV-I. None of the five patients had a history of antecedent blood transfusion, multiple sexual partners, or intravenous drug use. There is no evidence of adult T-cell leukemia or lymphoma in any of the patients or their families. Given the increasing seroprevalence of HTLV-I in the United States, clinicians need to be alert to new cases of this disorder.

Infection with the human T-lymphotropic virus type I. A review for clinicians.

The human T-cell lymphotropic virus type I (HTLV-I) is the first retrovirus identified in humans. It has been responsible for a number of clinical syndromes, most notably adult T-cell leukemia or lymphoma and tropical spastic paraparesis. In the United States, infection with this virus is most frequently found in specific subsets of our population, particularly in those who live in the southeastern states, have southern Japanese ancestry, or share intravenous drug paraphernalia. Understanding the epidemiology and clinical manifestations of this virus is necessary to properly diagnose and care for patients with HTLV-I infection.

Cytotoxicity of Shiga toxin for primary cultures of human colonic and ileal epithelial cells.

Shiga toxin purified from Shigella dysenteriae 1 was cytotoxic to cultured epithelial cells from human colon and ileum. The cytotoxicity, which affected only about 50% of treated cells, was neutralized by rabbit antiserum monospecific for Shiga toxin and mediated by protein synthesis inhibition.

Glucagon enhances growth of cultured human colorectal cancer cells in vitro.

Early passage in vitro cultures of colorectal adenocarcinoma cells were used to determine if glucagon exerts a direct effect on growth of human colon cancer cells. Growth response assays indicated that glucagon generally stimulated growth between 2 and 10 micrograms/ml, with peak responses at 5 to 10 micrograms/ml. When glucagon-treated and control cultures were compared, 12 of the 14 cultures (86 percent) were stimulated by glucagon, with an increase in cells from 41 to 100 percent. The other two cultures did not respond to glucagon. These in vitro results suggest that glucagon may enhance growth of most colon cancer cells. Further studies on responsiveness to glucagon may help elucidate mechanisms of oncogenesis and suggest new therapeutic protocols for patients with colorectal cancer.