Inhibition of vascular endothelial growth factor-induced angiogenesis suppresses tumour growth in vivo

The development of new blood vessels (angiogenesis) is required for many physiological processes including embryogenesis, wound healing and corpus luteum formation. Blood vessel neoformation is also important in the pathogenesis of many disorders, particularly rapid growth and metastasis of solid tumours. There are several potential mediators of tumour angiogenesis, including basic and acidic fibroblast growth factors, tumour necrosis factor-alpha and transforming factors-alpha and -beta. But it is unclear whether any of these agents actually mediates angiogenesis and tumour growth in vivo. Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen and an angiogenesis inducer released by a variety of tumour cells and expressed in human tumours in situ. To test whether VEGF may be a tumour angiogenesis factor in vivo, we injected human rhabdomyosarcoma, glioblastoma multiforme or leiomyosarcoma cell lines into nude mice. We report here that treatment with a monoclonal antibody specific for VEGF inhibited the growth of the tumours, but had no effect on the growth rate of the tumour cells in vitro. The density of vessels was decreased in the antibody-treated tumours. These findings demonstrate that inhibition of the action of an angiogenic factor spontaneously produced by tumour cells may suppress tumour growth in vivo.

Apo2L/TRAIL-dependent recruitment of endogenous FADD and caspase-8 to death receptors 4 and 5

Fas (APO-1/CD95) and tumor necrosis factor receptor 1 (TNFR1) trigger apoptosis by recruiting the apoptosis initiator caspase-8 through the adaptor FADD. Fas binds FADD directly, whereas TNFR1 binds FADD indirectly, through TRADD. TRADD alternatively recruits the NF-kappaB-inducing adaptor RIP. The TNF homolog Apo2L/TRAIL triggers apoptosis through two distinct death receptors, DR4 and DR5; however, receptor over-expression studies have yielded conflicting results on the ligand's signaling mechanism. Apo2L/TRAIL induced homomeric and heteromeric complexes of DR4 and DR5 and stimulated recruitment of FADD and caspase-8 and caspase-8 activation in nontransfected cells. TRADD and RIP, which bound TNFR1, did not bind DR4 and DR5. Thus, Apo2L/TRAIL and FasL initiate apoptosis through similar mechanisms, and FADD may be a universal adaptor for death receptors.

C9orf72 is required for proper macrophage and microglial function in mice

Expansions of a hexanucleotide repeat (GGGGCC) in the noncoding region of the C9orf72 gene are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. Decreased expression of C9orf72 is seen in expansion carriers, suggesting that loss of function may play a role in disease. We found that two independent mouse lines lacking the C9orf72 ortholog (3110043O21Rik) in all tissues developed normally and aged without motor neuron disease. Instead, C9orf72 null mice developed progressive splenomegaly and lymphadenopathy with accumulation of engorged macrophage-like cells. C9orf72 expression was highest in myeloid cells, and the loss of C9orf72 led to lysosomal accumulation and altered immune responses in macrophages and microglia, with age-related neuroinflammation similar to C9orf72 ALS but not sporadic ALS human patient tissue. Thus, C9orf72 is required for the normal function of myeloid cells, and altered microglial function may contribute to neurodegeneration in C9orf72 expansion carriers.

Interleukin-6 and soluble interleukin-6 receptors in the synovial fluids from rheumatoid arthritis patients are responsible for osteoclast-like cell formation

Chronic immune responses and inflammatory reactions in rheumatoid arthritis (RA) often cause severe destruction of cartilage and bone, but its mechanism is still a matter of controversy. We reported that interleukin-6 (IL-6) alone does not induce osteoclast formation, but soluble interleukin-6 receptors (sIL-6R) triggered the formation in the presence of IL-6 in cocultures of murine osteoblastic cells and bone marrow cells. In this study, we examined the involvement of sIL-6R and IL-6 in joint destruction in patients with RA. Although the frequency of patients having osteoclast-like multinucleated cells in synovium derived from the knee joint was not significantly different between RA (65%) and osteoarthritis (OA) patients (43%), the number of osteoclast-like cells found in the synovium was greater in the former than in the latter. Multinucleated cells obtained from RA synovium expressed the osteoclast-specific phenotype such as tartrate-resistant acid phosphatase, carbonic anhydrase II, vacuolar proton-ATPase and vitronectin receptors at similar levels to those from a human giant cell tumor of bone. The concentration of both IL-6 and sIL-6R was significantly higher in the synovial fluids from patients with RA than with OA. The concentration of IL-6 and sIL-6R correlated well with the roentgenologic grades of joint destruction. Dose-response curves for human IL-6 and human sIL-6R in inducing osteoclast-like cell formation in cocultures indicated that the RA synovial fluids contained sufficient IL-6 and sIL-6R to induce osteoclastogenesis. When synovial fluids from RA and OA patients were added to the cocultures, some of the RA synovial fluids containing high levels of IL-6 and sIL-6R stimulated osteoclast-like cell formation, which was strikingly inhibited by adding anti-IL-6R antibody simultaneously. These results suggest that IL-6 in the RA synovial fluids is at least in part responsible for joint destruction in the presence of sIL-6R through osteoclastogenesis.

Identification of CRAMP, a cathelin-related antimicrobial peptide expressed in the embryonic and adult mouse

Cathelicidins are the precursors of potent antimicrobial peptides that have been identified in several mammalian species. Prior work has suggested that members of this gene family can participate in host defense through their antimicrobial effects and activate mesenchymal cells during wound repair. To permit further study of these proteins a reverse transcriptase-polymerase chain reaction approach was used to identify potential mouse homologs. A full-length 562-base pair cDNA clone was obtained encoding an NH2-terminal prepro domain homologous to other cathelicidins and a unique COOH-terminal peptide. This gene, named Cramp for cathelin-related antimicrobial peptide, was mapped to chromosome 9 at a region of conserved synteny to which genes for cathelicidins have been mapped in pig and man. Northern blot analysis detected a 1-kilobase transcript that was expressed in adult bone marrow and during embryogenesis as early as E12, the earliest stage of blood development. Reverse transcriptase-polymerase chain reaction also detected CRAMP expression in adult testis, spleen, stomach, and intestine but not in brain, liver, heart, or skeletal muscle. To evaluate further the expression and function of CRAMP, a peptide corresponding to the predicted COOH-terminal region was synthesized. CD spectral analysis showed that CRAMP will form an amphipathic alpha-helix similar to other antimicrobial peptides. Functional studies showed CRAMP to be a potent antibiotic against Gram-negative bacteria by inhibiting growth of a variety of bacterial strains (minimum inhibitory concentrations 0.5-8.0 microM) and by permeabilizing the inner membrane of Escherichia coli directly at 1 microM. Antiserum against CRAMP revealed abundant expression in myeloid precursors and neutrophils. Thus, CRAMP represents the first antibiotic peptide found in cells of myeloid lineage in the mouse. These data suggest that inflammatory cells in the mouse can use a nonoxidative mechanism for microbial killing and permit use of the mouse to study the role such peptides play in host defense and wound repair.

Comparison of three rodent neuropathic pain models

To characterize various animal models of neuropathic pain, we compared three previously developed rat models using the same behavioral testing methods. These models involve: (1) chronic constriction injury by loose ligation of the sciatic nerve (CCI); (2) tight ligation of the partial sciatic nerve (PSL); and (3) tight ligation of spinal nerves (SNL). Comparisons were made for the time course of behavioral signs representing various components of neuropathic pain as well as for the effects of surgical sympathectomy. In general, all three methods of peripheral nerve injury produced behavioral signs of both ongoing and evoked pain with similar time courses. However, there was a considerable difference in the magnitude of each pain component between models. Signs of mechanical allodynia were largest in the SNL injury and smallest in the CCI model. On the other hand, behavioral signs representing ongoing pain were much more prominent in the CCI model than in the other two. Although the behavioral signs of neuropathic pain tended to decrease after sympathectomy in all three models, the change was most evident in the SNL model. The results of the present study suggest that the three rat models tested have contrasting features, yet all are useful neuropathic pain models, possibly representing different populations of human neuropathic pain patients.

Activated human T cells directly induce osteoclastogenesis from human monocytes: possible role of T cells in bone destruction in rheumatoid arthritis patients

OBJECTIVE

To elucidate the direct role of human T cells in the induction of osteoclastogenesis in rheumatoid arthritis (RA), by studying human monocytes and the pathogenetic roles of receptor activator of nuclear factor kappaB ligand (RANKL), RANK, and osteoprotegerin (OPG).

METHODS

Synovial tissue obtained at total knee replacement was stained immunohistologically using anti-RANKL, CD3, and CD4 antibodies. Synovial fluid was obtained from patients with RA, osteoarthritis (OA), gout, or trauma. Concentrations of the soluble form of RANKL (sRANKL) and OPG in the synovial fluid were measured by enzyme-linked immunosorbent assay. Activated T cells from peripheral blood mononuclear cells (PBMC) of healthy volunteers were cultured with human monocytes from PBMC.

RESULTS

Immunostaining of the synovial tissue of RA patients demonstrated that RANKL-positive cells were detected in a subset of fibroblast-like synoviocytes and infiltrating mononuclear cells. Double immunostaining revealed that RANKL-positive cells were detected in a subset of CD3+ cells and CD4+ cells. An increased concentration of sRANKL and a decreased concentration of OPG were detected in synovial fluid from RA patients. The ratio of the concentration of sRANKL to that of OPG was significantly higher in synovial fluid of RA patients than in synovial fluid of patients with OA or gout. The activated T cells expressing RANKL induced osteoclastogenesis from autologous peripheral monocytes. The role of RANKL in this osteoclastogenetic process was confirmed by dose-dependent inhibition by OPG.

CONCLUSION

The present study is the first to demonstrate osteoclastogenesis using human-derived T cells and monocytes. In addition, the present findings suggest that excess production of RANKL by activated T cells increases the level of sRANKL in synovial fluid and may contribute to osteoclastic bone resorption in RA patients.

The vascular endothelial growth factor proteins: identification of biologically relevant regions by neutralizing monoclonal antibodies

Angiogenesis plays critical roles in organ development during embryonic and fetal life, wound healing and in a variety of pathological conditions. Vascular endothelial growth factor (VEGF) is a secreted growth factor specific for vascular endothelial cells which induces angiogenesis in vivo. To gain a better understanding of the physiological role of VEGF, we have generated and characterized four murine monoclonal antibodies (mAbs) using the 165 amino acid species of recombinant human VEGF as immunogen. These mAbs (A3.13.1, A4.6.1, B4.3.1 and B2.6.2) belong to IgG1 isotype and have high affinities for VEGF (dissociation constants range from 2.2 x 10(-9) to 4 x 10(-10) M). Two different epitopes were detected with these mAbs. One epitope is recognized by mAbs A3.13.1 and B2.6.2, and the other recognized by mAbs A4.6.1 and B4.3.1. The epitope recognized by mAb A4.6.1 appears to be continuous while mAb B2.6.2 recognizes a discontinuous epitope. MAb A4.6.1 recognized three species of VEGF generated by alternative splicing, VEGF121, VEGF165 and VEGF189 while mAb B2.6.2 binds only VEGF165 and VEGF189. Results using an in vitro bovine adrenal cortex endothelial cell proliferation assay, in in vivo vascular permeability assay and an in vivo embryonic chicken angiogenesis assay showed that mAb A4.6.1 has potent VEGF neutralizing activities. MAb A4.6.1 was shown to block the binding of VEGF to its receptor(s) suggesting the inhibitory mechanism for VEGF activities. These well-defined mAbs should be very powerful tools to understand the structure-function relationship of various domains of VEGF and may have therapeutic potential.

Exponential Gain and Saturation of a Self-Amplified Spontaneous Emission Free-Electron Laser

Self-amplified spontaneous emission in a free-electron laser has been proposed for the generation of very high brightness coherent x-rays. This process involves passing a high-energy, high-charge, short-pulse, low-energy-spread, and low-emittance electron beam through the periodic magnetic field of a long series of high-quality undulator magnets. The radiation produced grows exponentially in intensity until it reaches a saturation point. We report on the demonstration of self-amplified spontaneous emission gain, exponential growth, and saturation at visible (530 nanometers) and ultraviolet (385 nanometers) wavelengths. Good agreement between theory and simulation indicates that scaling to much shorter wavelengths may be possible. These results confirm the physics behind the self-amplified spontaneous emission process and forward the development of an operational x-ray free-electron laser.

ndhF sequence evolution and the major clades in the sunflower family

An extensive sequence comparison of the chloroplast ndhF gene from all major clades of the largest flowering plant family (Asteraceae) shows that this gene provides approximately 3 times more phylogenetic information than rbcL. This is because it is substantially longer and evolves twice as fast. The 5' region (1380 bp) of ndhF is very different from the 3' region (855 bp) and is similar to rbcL in both the rate and the pattern of sequence change. The 3' region is more A+T-rich, has higher levels of nonsynonymous base substitution, and shows greater transversion bias at all codon positions. These differences probably reflect different functional constraints on the 5' and 3' regions of ndhF. The two patterns of base substitutions of ndhF are particularly advantageous for phylogenetic reconstruction because the conserved and variable segments can be used for older and recent groups, respectively. Phylogenetic analyses of 94 ndhF sequences provided much better resolution of relationships than previous molecular and morphological phylogenies of the Asteraceae. The ndhF tree identified five major clades: (i) the Calyceraceae is the sister family of Asteraceae; (ii) the Barnadesioideae is monophyletic and is the sister group to the rest of the family; (iii) the Cichorioideae and its two basal tribes Mutisieae and Cardueae are paraphyletic; (iv) four tribes of Cichorioideae (Lactuceae, Arctoteae, Liabeae, and Vernonieae) form a monophyletic group, and these are the sister clade of the Asteroideae; and (v) the Asteroideae is monophyletic and includes three major clades.

Properties of biomolecules measured from atomic force microscope images: a review

AFM images can be used to obtain quantitative or qualitative information about the properties of biomaterials. Examples presented here are: (1) Persistence length measurements of moving and stationary DNA molecules. (2) Force mapping to measure properties such as the elasticity of cells and vesicles. (3) Phase mode imaging to detect variations in materials and properties of the sample surface. (4) Imaging of surfaces at different constant forces.

Production of the RANTES chemokine in delayed-type hypersensitivity reactions: involvement of macrophages and endothelial cells

To understand the selective accumulation of memory T helper lymphocytes and of macrophages in delayed-type hypersensitivity (DTH) granulomas, we studied the in situ production of RANTES, a chemokine initially characterized on the basis of its in vitro chemotactic properties for each of these cell populations. RANTES gene expression was studied by in situ hybridization in 15 human lymph nodes presenting typical DTH lesions related to either sarcoidosis or tuberculosis. A positive signal was detected in all cases. Labeling was specific for the DTH lesions, as very few if any positive cells were detected in the normal residual lymphoid tissue surrounding them or in reactive lymph nodes involved in a B lymphocyte response. RANTES gene expression was associated with the production of the protein, which was detected by immunochemistry in DTH lymph nodes. The morphological characteristics and distribution of positive cells in in situ hybridization and immunochemical experiments indicated that macrophages and endothelial cells, two cell populations not previously reported to produce RANTES, contributed to its production in DTH reactions. The ability of macrophages and endothelial cells to produce RANTES was confirmed by in vitro studies with alveolar macrophages and umbilical vein endothelial cells. In view of the chemotactic properties of RANTES for a limited range of cell populations, these results suggest that RANTES production in DTH granulomas may play a role in the selective accumulation of macrophages and memory T helper lymphocytes characterizing this type of cell-mediated immune reaction, and that macrophages and endothelial cells are involved in this production.

Tight monolayers of rat alveolar epithelial cells: bioelectric properties and active sodium transport

Because the pulmonary alveolar epithelium separates air spaces from a fluid-filled compartment, it is expected that this barrier would be highly resistant to the flow of solutes and water. Investigation of alveolar epithelial resistance has been limited due to the complex anatomy of adult mammalian lung. Previous efforts to study isolated alveolar epithelium cultured on porous substrata yielded leaky monolayers. In this study, alveolar epithelial cells isolated from rat lungs and grown on tissue culture-treated Nucleopore filters resulted in tight monolayers with transepithelial resistance greater than 2,000 omega.cm2. Changes in bioelectric properties of these alveolar epithelial monolayers in response to ouabain, amiloride, and terbutaline are consistent with active sodium transport across a polarized barrier. 22Na flux measurements under short-circuit conditions directly confirm net transepithelial absorption of sodium by alveolar epithelial cells in the apical to basolateral direction, comparable to the observed short-circuit current (4.37 microA/cm2). The transport properties of these tight monolayers may be representative of the characteristics of the mammalian alveolar epithelial barrier in vivo.

Dynamic glenohumeral stability provided by the rotator cuff muscles in the mid-range and end-range of motion. A study in cadavera

BACKGROUND

Both static and dynamic factors are responsible for glenohumeral joint stability. We hypothesized that dynamic factors could potentially operate throughout the entire range of glenohumeral motion, although capsuloligamentous restraints (a static factor) have been thought to be primarily responsible for stability in the end-range of motion. The purpose of this study was to quantitatively compare the dynamic glenohumeral joint stability in the end-range of motion (the position of anterior instability) with that in the mid-range by investigating the force components generated by the rotator cuff muscles.

METHODS

Ten fresh-frozen shoulders from human cadavera were obtained, and all soft tissues except the rotator cuff were removed. The glenohumeral capsule was resected after the rotator cuff muscles had been released from the scapula. A specially designed frame positioned the humerus in 60 degrees of abduction and 45 degrees of extension with respect to the scapula. The compressive and shear components on the glenoid were measured before and after a constant force was applied individually to each muscle with the humerus in five different positions (from neutral to 90 degrees of external rotation). The dynamic stability index, a new biomechanical parameter reflecting these force components and the concavity-compression mechanism, was calculated. The higher the dynamic stability index, the greater the dynamic glenohumeral stability.

RESULTS

In the mid-range of motion, the supraspinatus and subscapularis provided higher dynamic stability indices than did the other muscles (p < 0.05). On the other hand, when the position of anterior instability was simulated in the end-range of motion, the subscapularis, infraspinatus, and teres minor provided significantly higher dynamic stability indices than did the supraspinatus (p < 0.005).

CONCLUSIONS

The rotator cuff provided substantial anterior dynamic stability to the glenohumeral joint in the end-range of motion as well as in the mid-range.

CLINICAL RELEVANCE

A glenohumeral joint with a lax capsule and ligaments might be stabilized dynamically in the end-range of motion if the glenoid concavity is maintained and the function of the external and internal rotators, which are efficient stabilizers in this position, is enhanced.

Ia antigen-bearing B cell tumor lines can present protein antigen and alloantigen in a major histocompatibility complex-restricted fashion to antigen-reactive T cells

Several Ia-positive BALB/c B cell tumor lines were screened for their ability to present alloantigen and protein antigens to alloreactive and antigen-reactive T cells. Of six Ia-positive tumor lines studied, three were found to be effective as antigen presenting cells (APC). Indeed, on a per cell basis, one of the stimulatory lines, A20.3, was substantially more effective than whole spleen cells. The other three lines, although Ia-positive, were nonstimulatory. A20.3 was chosen for further study. This tumor appeared to behave like the conventional APC because (a) the tumor cells presented alloantigen, (b) they presented protein antigen in an MHC-restricted fashion to both primed donor T cells and to long-term continuous T cell lines, (c) alloantigen presentation was blocked by the inclusion of an anti-Ia antibody in the culture system, and (d) A20.3 cells could be effectively pulsed with antigen, although the continuous presence of antigen in the culture system resulted in a superior response. The addition of an exogenous source of interleukin 1 proved necessary to obtain an alloreactive but not an antigen-specific T cell response, although its inclusion did enhance the magnitude of antigen-stimulated proliferation. These tumor cells should prove useful in studying the biochemical events that occur during antigen processing and the requirements for T cell triggering by processed antigen in association with Ia molecules.

Isotype-dependent inhibition of tumor growth in vivo by monoclonal antibodies to death receptor 4

To explore an approach for death receptor targeting in cancer, we developed murine mAbs to human death receptor 4 (DR4). The mAb 4H6 (IgG1) competed with Apo2L/TNF-related apoptosis-inducing ligand (DR4's ligand) for binding to DR4, whereas mAb 4G7 (IgG2a) did not. In vitro, both mAbs showed minimal intrinsic apoptosis-inducing activity, but each triggered potent apoptosis upon cross-linking. In a colon tumor nude mouse model in vivo, mAb 4H6 treatment without addition of exogenous linkers induced apoptosis in tumor cells and caused complete tumor regression, whereas mAb 4G7 partially inhibited tumor growth. An IgG2a isotype switch variant of mAb 4H6 was much less effective in vivo than the parent IgG1-4H6, despite similar binding affinities to DR4. The same conclusion was obtained by comparing other IgG1 and IgG2 mAbs to DR4 for their anti-tumor activities in vivo. Thus, the isotype of anti-DR4 mAb may be more important than DR4 binding affinity for tumor elimination in vivo. Anti-DR4 mAbs of the IgG1 isotype may provide a useful tool for investigating the therapeutic potential of death receptor targeting in cancer.

Beyond neurovascular coupling, role of astrocytes in the regulation of vascular tone

The brain possesses two intricate mechanisms that fulfill its continuous metabolic needs: cerebral autoregulation, which ensures constant cerebral blood flow over a wide range of arterial pressures and functional hyperemia, which ensures rapid delivery of oxygen and glucose to active neurons. Over the past decade, a number of important studies have identified astrocytes as key intermediaries in neurovascular coupling (NVC), the mechanism by which active neurons signal blood vessels to change their diameter. Activity-dependent increases in astrocytic Ca(2+) activity are thought to contribute to the release of vasoactive substances that facilitate arteriole vasodilation. A number of vasoactive signals have been identified and their role on vessel caliber assessed both in vitro and in vivo. In this review, we discuss mechanisms implicating astrocytes in NVC-mediated vascular responses, limitations encountered as a result of the challenges in maintaining all the constituents of the neurovascular unit intact and deliberate current controversial findings disputing a main role for astrocytes in NVC. Finally, we briefly discuss the potential role of pericytes and microglia in NVC-mediated processes.

Involvement of APO2 ligand/TRAIL in activation-induced death of Jurkat and human peripheral blood T cells

The interaction of Fas with Fas ligand (FasL) mediates activation-induced cell death (AICD) of T hybridomas and of mature T lymphocytes. The TNF/TNF receptor system also plays a significant role in AICD of mature T cells and in the maintenance of peripheral tolerance. We previously demonstrated that in human Jurkat leukemia cells, AICD is triggered mainly by the rapid release of preformed FasL upon TCR stimulation. In the present work, we show that the cytotoxic cytokine APO2 ligand (APO2L; also known as TRAIL) is constitutively expressed as an intracytoplasmic protein in Jurkat T cells and derived sublines. APO2L is also detected in fresh human peripheral blood mononuclear cells (PBMC) from a significant number of donors, and the amount of both FasL and APO2L substantially increases upon blast generation. A neutralizing anti-APO2L monoclonal antibody (mAb) partially suppresses the cytotoxicity induced by supernatants of phytohemagglutinin (PHA)-prestimulated Jurkat or human PBMC on non-activated Jurkat cells, indicating that APO2L is released by these cells and contributes to AICD. A combination of neutralizing anti-APO2L and anti-Fas mAb blocks around 60 % of the toxicity associated with supernatants from PHA-activated human PBMC. These results show that FasL and APO2L account for the majority of cytotoxic activity released during AICD, and suggest that additional uncharacterized factors may also contribute to this process.

The phylogeny of the Asteridae sensu lato based on chloroplast ndhF gene sequences

A phylogenetic study of Asteridae sensu lato was conducted based on chloroplast ndhF gene sequences for 116 ingroup and 13 outgroup species. Prior molecular studies based on rbcL sequences identified terminal groups corresponding to families, but were unable to resolve relationships among them. These results are largely consistent with earlier rbcL studies, but provide much greater resolution and stronger bootstrap support throughout the tree. The parsimony analysis found eight equally parsimonious trees, all of which recognize four major clades with the following relationship: (Cornales (Ericales (Euasterids I, Euasterids II))). Euasterids I includes (Garryales ((Solanales, Boraginaceae) (Gentianales, Lamiales))), although with weak support for relationships among the named clades. Euasterids II includes (Aquifoliales (Asterales (Apiales, Dipsacales))) with strong support for these relationships. Relationships within Ericales are weakly supported and merit further attention.

Nonspecific interstitial pneumonia with fibrosis: radiographic and CT findings in seven patients

PURPOSE

To describe the radiographic and computed tomographic (CT) findings in seven patients with nonspecific interstitial pneumonia with fibrosis (NIP).

MATERIALS AND METHODS

NIP was proved pathologically in all patients. Findings at radiography and initial and 1-15-month follow-up CT were reviewed.

RESULTS

The predominant radiographic abnormalities were areas of patchy parenchymal opacification present bilaterally in the middle and lower lung zones in six patients; in one patient, the chest radiograph depicted no abnormality. The most common finding observed on initial thin-section CT scans was bilateral, patchy areas of ground-glass attenuation present alone or with areas of consolidation in five patients (71%) or irregular lines in two (29%). At follow-up CT, the initial parenchymal abnormalities had resolved completely in three patients, improved in another three, and persisted in one.

CONCLUSION

Bilateral patchy areas of opacity depicted radiographically and good clinical response to treatment may differentiate NIP from other interstitial pneumonias.

Monolayers of human alveolar epithelial cells in primary culture for pulmonary absorption and transport studies

PURPOSE

To develop a cell culture model of human alveolar epithelial cells in primary culture for the in vitro study of pulmonary absorption and transport.

METHODS

Type II pneumocytes isolated from normal human distal lung tissue by enzyme treatment and subsequent purification were plated on fibronectin/collagen coated polyester filter inserts, and cultured using a low-serum growth medium. Characterization of the cell culture was achieved by bioelectric measurements, cell-specific lectin binding, immunohistochemical detection of cell junctions, and by assessment of transepithelial transport of dextrans of varying molecular weights.

RESULTS

In culture, the isolated cells spread into confluent monolayers, exhibiting peak transepithelial resistance of 2,180 +/- 62 ohms x cm2 and potential difference of 13.5 +/- 1.0 mV (n = 30-48), and developing tight junctions as well as desmosomes. As assessed by lectin-binding, the cell monolayers consisted of mainly type I cells with some interspersed type II cells, thus well mimicking the situation in vivo. The permeability of hydrophilic macromolecular FITC-dextrans across the cell monolayer was found to be inversely related to their molecular size, with Papp values ranging from 1.7 to 0.2 x 10(-8) cm/sec.

CONCLUSIONS

A primary cell culture model of human alveolar epithelial cells has been established, which appears to be a valuable in vitro model for pulmonary drug delivery and transport studies.

Vitreoscilla hemoglobin. Intracellular localization and binding to membranes

The obligate aerobic bacterium, Vitreoscilla, synthesizes elevated quantities of a homodimeric hemoglobin (VHb) under hypoxic growth conditions. Expression of VHb in heterologous hosts often enhances growth and product formation. A role in facilitating oxygen transfer to the respiratory membranes is one explanation of its cellular function. Immunogold labeling of VHb in both Vitreoscilla and recombinant Escherichia coli bearing the VHb gene clearly indicated that VHb has a cytoplasmic (not periplasmic) localization and is concentrated near the periphery of the cytosolic face of the cell membrane. OmpA signal-peptide VHb fusions were transported into the periplasm in E. coli, but this did not confer any additional growth advantage. The interaction of VHb with respiratory membranes was also studied. The K(d) values for the binding of VHb to Vitreoscilla and E. coli cell membranes were approximately 5-6 microm, a 4-8-fold higher affinity than those of horse myoglobin and hemoglobin for these same membranes. VHb stimulated the ubiquinol-1 oxidase activity of inverted Vitreoscilla membranes by 68%. The inclusion of Vitreoscilla cytochrome bo in proteoliposomes led to 2.4- and 6-fold increases in VHb binding affinity and binding site number, respectively, relative to control liposomes, suggesting a direct interaction between VHb and cytochrome bo.

Mapping epitopes on the insulin molecule using monoclonal antibodies

A panel of 18 monoclonal antibodies (mAb) delta to insulin have been prepared and used to begin to map antigenic determinants on the insulin molecule. All 18 mAb were of the IgG class, with 14 IgG1, 2 IgG2a and 2 IgG2b. The affinities of these mAb for their immunizing insulin ranged from 1 X 10(6) to 3 X 10(8) 1/M. The epitope recognized by three of the mAb, 1, 7 and 16 involves the three residues of the A chain, A 8-10, the so called A chain-loop determinant. This A chain loop is one of the most evolutionarily diverse regions of insulins from different species. Another mAb, 10, has been hypothesized to recognize a nearby epitope composed of the A chain residues, A4 and A8 and a B chain residue, B29, that are adjacent on the surface of the insulin molecule. Four of the mAb bind to synthetic B chain. The epitopes recognized by these 4 mAb and the last 10 mAb are unknown but the mAb are grouped according to their ability to bind to different species of insulin or proinsulin. The results of an 18 X 18 matrix analysis of pairs of mAb binding simultaneously to insulin indicate that, despite the finding that some mAb see similar antigenic sites on the insulin molecule, each of the mAb recognizes a unique site on the insulin molecule. Finally, a lower estimate of the number of possible antibodies made to insulin has been calculated to be greater than or equal to 115, a number only 10-fold lower than the lower limit of antibodies made to dinitrophenyl (DNP) or (4-hydroxy-5-iodo-3-nitrophenyl)acetyl (NIP), following hapten protein immunization.

Regulation of neutrophil interleukin 8 gene expression and protein secretion by LPS, TNF-alpha, and IL-1 beta

Neutrophils are possibly involved in the pathogenesis of various lung diseases through the release of numerous mediators. In the present study, we studied the regulation of IL-8 gene induction and protein secretion in human blood neutrophils. Northern blot analysis revealed that LPS increased IL-8 mRNA levels in neutrophils, with a maximal fivefold increase by 2 h. IL-8 mRNa levels returned to baseline values within 12 h. In contrast, LPS-stimulated monocytes demonstrated a sustained increase of IL-8 mRNA levels for more than 24 h. TNF-alpha, IL-1 beta, and phorbol myristate acetate also increased IL-8 mRNA levels in neutrophils. Immunohistochemical analysis confirmed that IL-8 was localized within stimulated neutrophils. IL-8 secretion by neutrophils and monocytes was quantified using a specific ELISA for IL-8. Resting neutrophils secreted minimal IL-8 activity. However when cells were stimulated with LPS, TNF-alpha, or IL-1B, neutrophils secreted IL-8. IL-8 secretion was most marked during the first 2 h after stimulation and decreased thereafter. In contrast, monocytes maintained a high rate of IL-8 secretion over 12 h. Although a single monocyte secreted 70-fold more IL-8 than did a single neutrophil after 4 h of incubation, the high abundance of neutrophils in peripheral blood made the neutrophil-secreted IL-8 more significant. During the first 2 h, neutrophils secreted approximately 40% of the IL-8 released by monocytes in the same volume of blood. This ratio decreased to 9% after 12 h. Neutrophil-secreted IL-8 may play an autocrine or paracrine role during the initial stage of inflammation.

Electrical activation of artificial muscles containing polyacrylonitrile gel fibers

Gel fibers made from polyacrylonitrile (PAN) are known to elongate and contract when immersed in caustic and acidic solutions, respectively. The amount of contraction for these pH-activated fibers is 50% or greater, and the strength of these fibers is shown to be comparable to that of human muscle. Despite these attributes, the need of strong acids and bases for actuation has limited the use of PAN gel fibers as linear actuators or artificial muscles. Increasing the conductivity by depositing platinum on the fibers or combining the fibers with graphite fibers has allowed for electrical activation of artificial muscles containing gel fibers when placed in an electrochemical cell. The electrolysis of water in such a cell produces hydrogen ions at an artificial muscle anode, thus locally decreasing the pH and causing the muscle to contract. Reversing the electric field allows the PAN muscle to elongate. A greater than 40% contraction in artificial muscle length in less than 10 min is observed when it is placed as an electrode in a 10 mM NaCl electrolyte solution and connected to a 10 V power supply. These results indicate potential in developing electrically activated PAN muscles and linear actuators, which would be much more applicable than chemically activated muscles.