Inhibition of human immunodeficiency virus-1 proliferation by liposome-encapsulated sense DNA to the 5' tat splice acceptor site

A liposome formulation containing a distearoylphosphatidylethanolamine analog was developed that was endocytosed by both lymphocytes and monocytes. This formulation was used to encapsulate sense and antisense 20-mer oligodeoxynucleotides to the 5' tat splice acceptor site of human immunodeficiency virus type 1. At a DNA concentration of 140 nM, the liposome-encapsulated sense DNA inhibited p24 production by as much as 84% in human peripheral blood leukocytes infected with "wild-type" virus. This treatment also reduced the number of peripheral blood leukocytes producing intracellular viral antigen by 71%. Of interest, no reduction in either parameter was observed for the antisense-containing liposomes. The results demonstrate the promise of a new liposomal delivery vehicle to inhibit human immunodeficiency virus replication by an entrapped oligodeoxynucleotide.

120-kD surface glycoprotein of Pneumocystis carinii is a ligand for surfactant protein A

Pneumocystis carinii is the most common cause of life-threatening pneumonia in immunocompromised patients. In the current study, surfactant protein A (SP-A), the major nonserum protein constituent of pulmonary surfactant, is demonstrated to bind P. carinii in a specific and saturable manner. SP-A is surface bound and does not appear to be internalized or degraded by the P. carinii organism. Furthermore, SP-A binding to P. carinii is time- and calcium-dependent and is competitively inhibited by mannosyl albumin. In the absence of calcium or the presence of excess mannosyl albumin, SP-A binding to P. carinii is reduced by 95 and 71%, respectively. SP-A avidly binds P. carinii with a Kd of 8 x 10(-9) M and an estimated 8.4 x 10(6) SP-A binding sites per P. carinii organism, as determined from Scatchard plots. SP-A is shown to bind P. carinii in vivo, and a putative binding site for SP-A on P. carinii is demonstrated to be the mannoserich surface membrane glycoprotein gp120. These findings suggest that P. carinii can interact with the phospholipid-rich material in the alveolar spaces by specifically binding a major protein constituent of pulmonary surfactant.

Modulation of Pneumocystis carinii adherence to cultured lung cells by a mannose-dependent mechanism

Pneumocystis carinii is an opportunistic parasite that attaches to the alveolar epithelium during the initiation of pneumonia. It is unknown whether P. carinii recognizes specific receptors on the surface of lung cells. Our study indicates that concanavalin A (Con A), a lectin that recognizes mannose-containing glycoproteins, binds to P. carinii organisms in a saturable manner with a binding affinity of Kd = 11 x 10(-6) mol/L and with 18.5 x 10(6) Con A binding sites per P. carinii organism. Con A binds predominantly to glycoprotein 120, a mannose-rich glycoprotein on the surface of P. carinii. Treatment of cultured target lung cells (A549 cells) with Con A resulted in dramatic reduction of P. carinii attachment, from 34.9% +/- 4.1% to 8.1% +/- 1.3% (p less than 0.001), suggesting that mannose-containing cell surface molecules may be important in P. carinii adherence to target lung cells. In contrast, treatment of P. carinii with Con A resulted in slightly increased adherence of P. carinii when compared with controls. The effects of Con A on P. carinii adherence were reversed when Con A treatments were conducted in the presence of excess mannose, the sugar ligand for Con A. Further, pretreatment of A549 cell monolayers with excess mannose (5000 micrograms/ml) resulted in significant reduction of P. carinii adherence to A549 cells, from 39.4% +/- 2.5% to 28.4% +/- 1.3% (p = 0.003). These studies, for the first time, implicate mannose-containing cell surface molecules as important mediators of attachment between P. carinii and target lung cells.

Acetylator phenotype-dependent and -independent expression of arylamine N-acetyltransferase isozymes in rapid and slow acetylator inbred rat liver

Although mouse, hamster, and rabbit models of the human N-acetylation polymorphism have been identified and characterized, many investigations of arylamine toxicity and carcinogenicity are carried out in the rat, particularly the Fischer 344 (F-344) inbred rat. We partially characterized a new rat model of the N-acetylation polymorphism by determining expression of arylamine N-acetyltransferase activities in liver cytosols derived from adult male inbred F-344, WKY, and their F1 hybrid rat strains. Levels of N-acetyltransferase activity differed significantly between the strains for many arylamine substrates, with highest levels in F-344, lowest levels in WKY, and intermediate levels in F1 hybrids of these two parental strains. However, for some other arylamine substrates, levels of N-acetyltransferase activity did not differ significantly between the rat strains. Partial purification of rat liver cytosols from the three strains resulted in identification of two N-acetyltransferase isozymes. The levels of N-acetyltransferase activity of one isozyme differed significantly between strains analogous to the pattern observed in crude cytosol. In contrast, the levels of N-acetyltransferase activity of the second isozyme did not differ between the strains. Based upon these results, the F-344 inbred strain is designated a rapid acetylator phenotype, the WKY inbred strain is designated a slow acetylator phenotype, and F1 hybrids of the two parental strains are designated intermediate acetylator phenotype. The identification of acetylator phenotype-dependent and -independent hepatic N-acetyltransferase isozymes in the inbred rat mimics the biochemical basis for acetylator phenotype-dependent and -independent expressions of N-acetylation in humans and other mammalian species.

Pneumocystis carinii attachment to cultured lung cells by pneumocystis gp 120, a fibronectin binding protein

Pneumocystis carinii is an extracellular organism which is thought to require attachment to alveolar epithelial cells for its growth and replication in humans. Fibronectin (Fn) binding to P. carinii is essential for optimal P. carinii attachment. This study demonstrates that gp120, a 110-120-kD membrane glycoprotein on P. carinii, mediates attachment of the organism to cultured lung cells and is the site of Fn binding to P. carinii. A 51Cr-labeled P. carinii binding assay was used to quantify attachment of the organism to the alveolar epithelial cell line A549. Addition of free gp120, purified from whole P. carinii organisms, caused a significant decrease in attachment of P. carinii to A549 cells from 44.2 +/- 5.5% to 22.4 +/- 4.2% (P less than 0.01). Preincubation of the P. carinii organisms with a polyclonal antibody to gp120 also resulted in a marked decrease in P. carinii attachment to A549 cells from 46.8% +/- 5.2% to 21.3 +/- 4.8% (P less than 0.01). Furthermore, addition of free gp120 to P. carinii organisms caused a significant reduction in specific binding of 125I-Fn to P. carinii (from 83.3 +/- 8.5 ng to 47.1 +/- 5.9 ng, P less than 0.01). Similarly, anti-gp 120 antibody decreased specific Fn binding to P. carinii from 74.3 +/- 8.4 ng to 25.5 +/- 5.3 ng (P less than 0.001). Solubilized P. carinii organisms separated by gel electrophoresis and blotted with 125I-Fn demonstrated specific binding of the 125I-Fn to gp120. In addition, a specific anti-beta 1-integrin antiserum reacted with gp120 by Western blot, suggesting structural homology between gp120 and the beta-subunit of integrins. Thus, the data suggest that the P. carinii membrane glycoprotein gp120 functions as a Fn binding protein and is required for optimal P. carinii attachment to alveolar epithelial cells.

Extrahepatic expression of the N-acetylation polymorphism toward arylamine carcinogens in tumor target organs of an inbred rat model

An N-acetylation polymorphism is described that is expressed toward arylamine carcinogens in tumor target organs of an inbred rat model. High levels (rapid acetylator phenotype) of arylamine carcinogen N-acetyltransferase activity were observed in kidney, colon, prostate and urinary bladder cytosols derived from Fischer (F-344) inbred rats, the strain most commonly used for tumor bioassay studies and the strain most particularly used in arylamine-induced colon and prostate cancer studies. Significantly lower (slow acetylator phenotype) levels of arylamine carcinogen N-acetyltransferase activity were observed in corresponding tissue cytosols derived from Wistar-Kyoto inbred rats. Intermediate levels of arylamine carcinogen N-acetyltransferase activity significantly different from both the parental strains were observed in F1 hybrids of the parental strains, consistent with codominant expression of two alleles at a single gene locus. The arylamine substrates exhibiting the acetylator phenotype-dependent N-acetyltransferase activities included p-aminobenzoic acid, p-aminosalicylic acid, p-phenetidine, p-aminophenol, 2-aminofluorene, 3,2'-dimethyl-4-aminobiphenyl, beta-naphthylamine and 4-aminobiphenyl, but not procainamide. Highest levels of arylamine carcinogen N-acetyltransferase were expressed consistently in colon cytosol, but expression of the N-acetylation polymorphism toward arylamine carcinogens was observed in each (kidney, colon, prostate and urinary bladder) of the tumor target organs. The expression of the N-acetylation polymorphism in tumor target organs suggests that the inbred rat model will be useful in assessing the role of acetylator phenotype in arylamine-induced cancers of the colon and prostate.

Non-radioactive single strand conformation polymorphism (SSCP) using the Pharmacia 'PhastSystem'

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Vision Assisted Robotics and Tape Technology in the Life-Science Laboratory: Applications to Genome Analysis

Recent proposals to analyze a number of major genomes have created a need for methods of rapidly manipulating and assaying very large numbers of specimens containing DNA fragments. Systems for sampling semi-solid biological material from mixed disordered arrays are required. These samples need to be sorted in an ordered format and stored in minimum space at known locations. It should be possible to recall them quickly from stock, individually or collectively, for duplication or re-ordering into new arrays for appropriate analysis. This article reviews a range of problems associated with high speed multiple specimen handling and assay in the molecular biology laboratory and outlines the solutions currently available to address these difficulties. Designs for automatic systems to manipulate biosamples and analyze DNA are presented.

Mechanism of Pneumocystis carinii attachment to cultured rat alveolar macrophages

Pneumocystis carinii (PC) pneumonia begins as an intra-alveolar process resulting in injury to the alveolar epithelium with subsequent invasion of the lung interstitium. The clearance of PC organisms from the alveolar space is a critical function of alveolar macrophages (AM), the resident alveolar phagocytic cells. In this study the mechanism of PC attachment to AM was determined using 51Cr-labeled organisms, with PC attachment reaching a maximum of 18.9 +/- 2.5% after 4 h. Attachment was significantly decreased by preincubation of the AM with a monoclonal anti-fibronectin antibody directed against the cell attachment site of fibronectin (from 17.8 +/- 2.2% to 8.3 +/- 1.0%, P less than 0.01), or by addition of the fibronectin cell binding site analogue Arg-Gly-Asp-Ser (RGDS) (from 18.1 +/- 2.3% to 2.9 +/- 0.8%, P less than 0.01). An anti-fibronectin monoclonal antibody directed against the heparin binding domain of fibronectin had no effect on PC attachment. Addition of the specific calcium ion chelating agent EGTA to the culture media similarly decreased attachment from 16.9 +/- 2.0% to 5.1 +/- 1.1% (P less than 0.01). Fibronectin-mediated attachment of PC to AM did not result in phagocytosis of the organisms by the AM as determined by chemiluminescence measurements. Therefore, the data indicate that PC attachment to AM is a calcium-dependent process mediated by the cell binding domain of fibronectin which does not trigger a phagocytic response by the AM.

Cell-adhesive motif in region II of malarial circumsporozoite protein

The segment of the malarial circumsporozoite (CS) protein designated Region II is highly conserved among different malarial species. A similar sequence is also present in several other proteins, including thrombospondin, properdin, and a blood-stage antigen of Plasmodium falciparum. By means of peptides synthesized from sequences of the Plasmodium vivax CS protein in the vicinity of Region II, it was found that two overlapping 18- to 20-amino acid peptides promoted the adhesion of a variety of human hematopoietic cell lines. The amino acid sequence valine-threonine-cysteineglycine (VTCG), contained within this common motif, was shown to be the critical sequence for the observed cell-adhesive properties.

Amiodarone-induced injury of human pulmonary artery endothelial cells: protection by alpha-tocopherol

Amiodarone is a potent antidysrhythmic drug that is associated with severe pulmonary toxicity. The mechanism of amiodarone pulmonary toxicity is poorly understood. To investigate the possible involvement of oxygen-derived metabolites in amiodarone-induced injury, 51Cr-labeled human pulmonary artery endothelial (HPAE) cells were incubated with amiodarone for 18 hr in the presence of various antioxidants and in hypoxic and hyperoxic conditions with cell injury quantified by 51Cr release, expressed as cytotoxic index. Amiodarone (10-50 microM) directly injured HPAE cells in a concentration-dependent manner, but the injury was not modulated by altering ambient oxygen concentrations. Furthermore, amiodarone-induced injury (30 microM) was not reduced by the following antioxidants: catalase, superoxide dismutase, ascorbic acid, dimethyl sulfoxide and ethanol. In contrast, toxicity from 30 microM amiodarone was significantly reduced by alpha-tocopherol (alpha-TOC) at 10, 20 and 40 microM from a cytotoxic index of 41.6 +/- 3.5 to 25.5 +/- 7.9, 10.61 +/- 5.4 and 3.1 +/- 2.8, respectively. As revealed by phase microscopy, alpha-TOC (40 microM) prevented any evidence of toxicity to the amiodarone-treated cells. Amiodarone concentrations in the HPAE cells incubated in the presence and absence of alpha-TOC were not significantly different, indicating that alpha-TOC did not interfere with the uptake of the drug by the cells. Similarly, amiodarone did not interfere with the uptake of alpha-TOC by the HPAE cells. Although the specific mechanism of action remains unclear, alpha-TOC affords nearly complete protection in vitro from the cellular injury induced by amiodarone.

Amiodarone-mediated increase in intracellular free Ca2+ associated with cellular injury to human pulmonary artery endothelial cells

The cardiac antidysrrhythmic drug amiodarone can give rise to potentially fatal pulmonary toxicity in large numbers of patients. The effect of amiodarone on Ca2+ homeostasis and cell injury has been studied using human pulmonary artery endothelial (HPAE) cells in vitro. Amiodarone produced a concentration-dependent increase in intracellular free Ca2+ concentration ( [Ca2+]i) to micromolar levels that are similar to those seen with physiological stimuli that increase [Ca2+]i. Unlike physiological stimuli, the rise in [Ca2+]i produced by amiodarone developed slowly and was maintained over at least 30 min. Omitting Ca2+ from the external medium reversibly prevented the amiodarone-induced rise in [Ca2+]i. Amiodarone treatment increased the apparent first order rate constants for 45Ca2+ influx and efflux in intact HPAE cells. 45Ca2+ accumulation into the endoplasmic reticulum of saponin-permeabilized HPAE cells was decreased by amiodarone treatment. The release of 45Ca2+ from the endoplasmic reticulum stores by the putative intracellular second messengers inositol-1,4,5-trisphosphate, arachidonic acid, and Ca2+ was blocked by amiodarone treatment. The changes in Ca2+ homeostasis coincide with an increase in [3H]deoxyglucose release as a measure of early cell injury by amiodarone. It is concluded that amiodarone can produce an increase in [Ca2+]i by an action on the plasma membrane that allows the influx of external Ca2+. This increase in [Ca2+]i, together with other changes in Ca2+ homeostasis, may be responsible for the early cell injury associated with amiodarone toxicity.

Effect of Klebsiella ozaenae on ciliary activity in vitro: implications in the pathogenesis of atrophic rhinitis

Klebsiella ozaenae is a gram-negative rod that has been isolated with relative frequency from patients with atrophic rhinitis. The relationship of this bacterium to the pathogenesis of atrophic rhinitis is not understood, and whether this bacterium is simply an opportunistic colonizer of the injured nose or the etiologic agent of the disease is unclear. This study was designed to investigate a potential role for bacterially produced cilioinhibition as a mechanism for the pathogenesis of atrophic rhinitis.

Mechanisms of amiodarone pulmonary toxicity

Amiodarone pulmonary toxicity is one of the most important examples of drug-induced lung disease by non-cancer chemotherapeutic agents. Current concepts suggest that patients may clinically present with an acute illness suggestive of a hypersensitivity picture or with a more chronic indolent course mimicking a malignant process. Likewise, the mechanism of amiodarone pulmonary toxicity suggests that at least two different pathways of toxicity exist: (1) an indirect mechanism characterized by influx of inflammatory or immune effector cells to the lung and (2) a direct toxic mechanism that results in lung parenchymal cell injury and a subsequent fibrotic response. Clearly, there is the potential for much crossover and interaction between the proposed pathways of toxicity in any given patient. A better understanding of the mechanism of amiodarone pulmonary toxicity will not only improve our diagnostic approaches to patients with this serious lung disorder, but will also provide the opportunity to develop unique therapeutic strategies that control the toxicity and potentially not interfere with the intended therapeutic efficacy of the drug.

Pneumocystis carinii: inhibition of lung cell growth mediated by parasite attachment

Pneumocystis carinii pneumonia is a significant cause of mortality in immunocompromised patients. Current concepts suggest that attachment of P. carinii to alveolar epithelium is required for development of pneumonia. We examined the mechanism of P. carinii adherence to cultured A549 cells, a permanent cell line derived from human alveolar epithelium. P. carinii adherence was quantified by measuring attachment of 51Cr-labeled P. carinii to cultured A549 cells. After 8 h of incubation, 37.4 +/- 4.2% of P. carinii were adherent to A549 cells. In the presence of agents known to impair cytoskeletal function, including 10(-5) M cytochalasin B, 10(-5) M colchicine, and 10(-5) M trimethylcolchicinic acid (TMCA), adherence was decreased from 57.4 +/- 4.2% to 9.3 +/- 3.4%, 12.5 +/- 3.6%, and 21.5 +/- 3.6%, respectively (P less than 0.01, all comparisons). Secondly, we examined the effect of P. carinii on the function of A549 cells. P. carinii resulted in significant impairment of A549 cell growth, indicating P. carinii adversely affected the function of target lung cells. A P. carinii:A549 cell ratio of 50:1 resulted in 43.5 +/- 2.9% inhibition of A549 cell growth (P less than 0.001). Additionally, TMCA, which significantly prevented attachment of P. carinii, reversed the impairment of A549 cell growth. These data demonstrate that P. carinii attachment to cultured lung cells can be quantified, is dependent on intact cytoskeletal function and is necessary for impairment of lung cell replication.

Identification of a T-cell epitope on the circumsporozoite protein of Plasmodium vivax

A series of overlapping peptides, representing sequences in the vicinity of region II on the Plasmodium vivax circumsporozoite protein, was synthesized. One of the peptides (PV-23), a 20-mer containing the 6 C-terminal amino acids of region II, was found to evoke an in vitro T-cell proliferative response in spleen cells from C3Hf (H-2km2) mice immunized with the peptide. These results demonstrate that PV-23 contains a T-cell epitope. To our knowledge, this is the first report of a T-cell epitope on the circumsporozoite protein of P. vivax.

Role of fibronectin in Pneumocystis carinii attachment to cultured lung cells

Attachment of pathogens to host cells is a prerequisite for the development of many infections. Pneumocystis carinii (PC) pneumonia is characterized by attachment of PC trophozoites to the alveolar epithelium. The mechanism of this process is unknown. Fibronectin (Fn) is a glycoprotein present in the alveolar space known to mediate cell-cell attachment, including the attachment of certain pathogens to host epithelial cells. In this study the binding of Fn to PC trophozoites has been characterized in vitro using 125I-Fn. Fn binds saturably and specifically to 6.4 x 10(5) binding sites per organism with an apparent binding constant, Kd, of 1.2 x 10(-8) M. Fn binding to PC was inhibited by the addition of Arg-Gly-Asp-Ser (RGDS), a tetrapeptide containing the active site of the cell-binding domain of Fn. PC attachment to an alveolar epithelial cell line was quantified using 51Cr-labeled PC trophozoites. Attachment was decreased from 24 +/- 1.9% to 12.1 +/- 1% (P less than 0.01) by the addition of an anti-Fn antibody, an effect that could be overcome by the addition of excess free Fn. It is concluded that binding of Fn to PC may be an important initial step in the attachment of the organism to alveolar epithelial cells. Furthermore, it appears that PC recognizes and binds to the RGDS cell attachment site of Fn.

Bronchoalveolar lavage fluid angiotensin-converting enzyme in interstitial lung diseases

In this study we evaluated the disease specificity of bronchoalveolar lavage fluid angiotensin-converting enzyme (BALF-ACE), its correlation with cellular constituents of bronchoalveolar lavage fluid (BALF), and for sarcoidosis, with other proposed markers of disease activity. Furthermore, the question of the clinical value of BALF-ACE determinations in in interstitial lung diseases or any of its subgroups was addressed. The study population consisted of 222 patients, 69 with biopsy proven sarcoidosis, 3 with hypersensitivity pneumonitis, 4 with acute histoplasmosis, 27 with idiopathic pulmonary fibrosis (IPF), 4 with rheumatoid arthritis-related interstitial fibrosis, 9 with pulmonary drug toxicity, 16 with pulmonary malignancies, 26 with other parenchymal lung disease entities, and 30 in whom the final diagnosis remained indeterminate. Elevated BALF-ACE concentrations were seen in all diagnostic categories. In sarcoidosis BALF-ACE levels correlated well with lavage lymphocyte counts (r = 0.49; p less than 0.0001), in contrast to IPF where they correlated well with lavage neutrophil counts (r = 0.51; p less than 0.007). The correlation of BALF-ACE and serum-ACE was significant. In sarcoidosis the mean BALF-ACE level was lower for patients with Stage-I chest roentgenographic patterns (0.664 U/L), compared to those with Stage II (1.112 U/L) and Stage III (1.083 U/L). It was concluded that elevated BALF-ACE levels are not specific for sarcoidosis. The correlations of BALF-ACE levels with different cellular constituents of BALF suggest a different cellular origin of BALF-ACE. In sarcoidosis BALF-ACE levels correlate well with other proposed markers of disease activity and seem to reflect pulmonary activity better than serum ACE.(ABSTRACT TRUNCATED AT 250 WORDS)

Behavioral and genetic interrelationships between locomotor activity and brain biogenic amines

1. Spontaneous locomotor activity of four mouse strains, the albino ICR, BALB/C, the black C57 BL/6 and the brown CDF-I, was studied in conjunction with whole brain content of select biogenic amines and major metabolites. The ICR and C57BL/6 mice scored the highest and lowest motility among the strains studied, respectively. 2. The ICR mice motility were the most sensitive to experimental stress among the mouse strains evaluated. 3. Brain dopamine concentrations were greater in ICR and CDF-I mice than the other two mouse strains. This is compared to high serotonin and 5-hydroxyindole acetic acid levels determined in C57BL/6. 4. A relationship between the ICR mouse strain with a high motility and the ratios of brain dopamine:homovanillic acid and between serotonin:5-hydroxyindole acetic acid was established. 5. An inverse relationship between ICR mice motility and the ratio of metanephrine and normetanephrine:3-methoxy-4-hydroxyphenylglycol (MHPG) was determined. 6. It is concluded that genetic predisposition may account for a relationship between motor activity and brain biogenic amines which may give insight into the susceptibility of different patients to the development of certain extrapyramidal diseases.

Suppression of experimental uveitis in rats by anti-I-A antibodies

I-region-associated (Ia) class II major histocompatibility complex (MHC) products are known to play a major role in autoimmunity. Effects of anti-I-A and anti-I-E monoclonal antibodies on development of experimental autoimmune uveitis (EAU) were investigated in Lewis rats. Prior to sensitization with S-antigen, seven groups of rats, six in each group, were injected intraperitoneally with one of the following agents. Groups 1, 2, and 3 (controls) received saline, RPMI and mouse immunoglobulin G (IgG), respectively. Groups 4 and 5 were injected with anti-I-E antibodies, 80 micrograms and 1000 micrograms, respectively. Similarly, groups 6 and 7 received anti-I-A, 100 micrograms and 750 micrograms, respectively. The treatments were repeated on days 1, 2, 5, 8, and 11 after S-antigen injection. All these animals were killed on day 18. In addition, two groups of rats sensitized with S-antigen were treated with 750 micrograms anti-I-A antibodies on days 5, 6, and 7 (group 8) and on days 7, 8 and 9 (group 9). An additional group (group 10) of Lewis rats was treated with 750 micrograms anti-I-A 1 day prior to and on days 1 and 2 after S-antigen injection. These group-10 animals were killed on day 31. Histopathologically, the enucleated globes of animals treated with high dose anti-I-A revealed marked suppression or inhibition of uveitis development. Such inhibition was virtually complete when the antibody was administered within a week of S-antigen injection, and the inhibitory effect lasted for at least 31 days.(ABSTRACT TRUNCATED AT 250 WORDS)