Phase IV clinical trial with a single treatment arm to evaluate bronchopulmonary penetration of isavuconazole in pulmonary transplant recipients (PBISA01): Study protocol clinical trial. (Preprint)

Background

Aspergillosis is the most frequently observed invasive fungal disease (IFD) in lung transplant recipients. Isavuconazole (ISA) has shown a better safety profile and noninferiority to voriconazole in the treatment of patients with IFD.

Objective

The aim of this study is to describe the bronchopulmonary pharmacokinetic profile of oral ISA by analyzing the degree of penetration in the epithelial lining fluid and alveolar macrophages in patients receiving lung transplantation with a diagnosis of IFD.

Methods

A total of 12 patients aged ≥18 years receiving a lung transplant with an IFD diagnosis and indication for ISA treatment and follow-up bronchoscopy will be included in the study. After 5 days of treatment with ISA and before the treatment is discontinued, the patients will be randomized (1:1:1:1) to perform the scheduled bronchoscopy at various times after the administration of ISA (2, 4, 8, and 12 hours). In total, 4 blood samples will be obtained per patient: at 72 hours after treatment initiation, on the day of the bronchoscopy, at the time of the bronchoalveolar lavage (simultaneously), and at 7 days after treatment initiation, to analyze tacrolimus and ISA plasma levels. ISA concentrations will be measured in plasma, epithelial lining fluid, and alveolar macrophages by a high-performance liquid chromatography/UV coupled to fluorescence method.

Results

Enrollment for the PBISA01 trial began in October 2020 and was completed in October 2021. All samples will be analyzed once recruitment is complete, and the results are expected to be published in October 2022.

Conclusions

There are no clinical studies that analyze the bronchopulmonary penetration of ISA. Bronchoalveolar lavage performed routinely in the follow-up of lung transplant recipients constitutes an opportunity to analyze the bronchopulmonary penetration of ISA.

Trial Registration

European Clinical Trials Register 2019-004240-30; www.clinicaltrialsregister.eu/ctr-search/trial/2019-004240-30/ES

International Registered Report Identifier (IRRID)

DERR1-10.2196/37275

Separation and properties of DNA polymerase from murine leukemia L1210 cells

The possible existence of several species of DNA-dependent DNA polymerases in mammalian cells in addition to those 2 polymerases which are the smaller enzyme from nucleus and larger one from cytoplasm each having distinct characteristics, have been reported recently. In order to examine the heterogeneity of DNA polymerases in murine leukemia L1210 cells and to characterize their general properties, we have attempted to separate the DNA polymerase activities from L1210 cells. By diethylaminoethyl (DEAE)-cellulose chromatography (0.2 M-1M KCl) of the whole cell extract from L1210 solubilized by 1% Triton X-100 and 0.5 mM ethylenediaminetetraacetate (EDTA), 4 fractions with DNA-dependent DNA polymerase activities were obtained and designated as DD-1, DD-2, DD-3, and DD-4 for eluents with each corresponding concentration of 0.2, 0.3, 0.5, and 0.7 M KCl, respectively. They were distinguishable in properties such as template preference, divalent cation requirement, DNase sensitivity, isoelectric point (pI) and the behavior on the phosphocellulose chromatography. DD-1 preferred native DNA as template exhibiting similar characteristic as nuclear polymerase with low molecular weight and insensitivity to SH-inhibitors. DD-2, DD-3, and DD-4 utilized activated DNA most efficiently, while activity of DD-3 increased even in the presence of DNase 1 under the condition where the others were completely inhibited. Distribution of DNA polymerase activities in the cells is discussed briefly.

Biochemical approaches to detection of viral related information in human acute leukemic cells

Two biochemical markers that have been utilized for the detection of viral related information in human acute leukemic cells are: 1) The reverse transcriptase and 2) a high molecular weight RNA with viral related nucleotide sequences. This paper summarizes evidence that shows that the reverse transcriptase isolated from human acute leukemic cells is biochemically related to the reverse transcriptase from RNA tumor viruses.

Intracellular autoantigens: diagnostic fingerprints but aetiological dilemmas

Autoimmune diseases such as systemic lupus erythematosus, scleroderma, Sjögren's syndrome, mixed connective tissue disease and dermato/polymyositis are each characterized by distinct sets of autoantigens and antibodies which confer on each disease a specific immune profile or fingerprint. These immune fingerprints have advanced our management of this group of diseases, as aids in differential diagnosis and earlier recognition. In lupus and scleroderma, multiple antigen/antibody systems characterize these fingerprints and the autoantigens appear to be located in separate cell compartments of the nucleus, nucleolus and cytoplasm. Because these antibodies are so distinctive for each disease, the response must be antigen driven or at least antigen directed. However, the apparent multi-focus location of the autoantigens poses a problem. It now appears that in scleroderma this dilemma may be explained by the consideration that at a certain time point in cell metabolism all the known autoantigens may be assembled at one location to form a single structural entity. It is possible that this assembly of antigens may be required for a specific cellular function. An autoimmune response to this transiently assembled structure comprising several different proteins and nucleic acids could result in the complex immune response seen in this disease.

Localization of the endogenous benzodiazepine ligand octadecaneuropeptide in the rat testis

Diazepam binding inhibitor (DBI) is the precursor of a family of peptides, including an octadecaneuropeptide (ODN), which share with DBI the ability to specifically displace benzodiazepines (BZD) from their receptors. BZD receptors have been found not only in the brain, but also in a variety of peripheral tissues, including the testis. To clarify the role of ODN in the testis, we have investigated the localization of ODN in the rat testis using two different cytochemical approaches: immunocytochemistry and in situ hybridization. Immunocytochemical localization was achieved using rabbit antibodies developed against rat ODN. At the light microscopic level, immunostaining was exclusively located in interstitial cells; the seminiferous tubules were totally unlabeled. In the developing rat, immunostaining in the interstitial cells was first detected in an 18-day-old fetus. The immunolabeling increased as a function of age to reach a plateau at 40 days of age. The ultrastructural localization of ODN was achieved by immunogold staining. The gold particles were exclusively found in the cytoplasm of Leydig cells. HPLC analysis performed in adult rat testicular extracts revealed that immunoreactive material was detected in a peak eluted later than synthetic rat ODN. The cellular distribution of ODN was also studied by in situ hybridization using a 35S-labeled single stranded RNA probe complementary to DBI mRNA. Hybridization signal obtained at the light microscopic level was only detected over interstitial cells. The data obtained clearly indicate that in the rat, Leydig cells synthesize ODN and accumulate ODN-like immunoreactivity. Since Leydig cells have been shown to contain BZD receptors, it might be hypothesized that ODN and/or other DBI-related peptides can play a role in Leydig cell regulation.

Studying single living cells and chromosomes by confocal Raman microspectroscopy

Many indirect methods have been developed to study the constitution and conformation of macromolecules inside the living cell. Direct analysis by Raman spectroscopy is an ideal complement to techniques using directly labelled fluorescent probes or of indirect labelling with mono- and polyclonal antibodies. The high information content of Raman spectra can characterize biological macromolecules both in solution and in crystals. The positions, intensities and linewidths of the Raman lines (corresponding to vibrational energy levels) in spectra of DNA-protein complexes yield information about the composition, secondary structure and interactions of these molecules, including the chemical microenvironment of molecular subgroups. The main drawback of the method is the low Raman scattering cross-section of biological macromolecules, which until now has prohibited studies at the level of the single cell with the exception of (salmon) sperm heads, in which the DNA is condensed to an exceptionally high degree. Ultraviolet-resonance Raman spectroscopy has been used to obtain single cell spectra (and F. Sureau and P. Y. Turpin, personal communication), but in this method absorption of laser light may impair the integrity of the sample. We have avoided this problem in developing a novel, highly sensitive confocal Raman microspectrometer for nonresonant Raman spectroscopy. Our instrument makes it possible to study single cells and chromosomes with a high spatial resolution (approximately less than 1 micron 3).

Sixteen discrete RNA components in the cytoplasmic ribosome of Euglena gracilis

We have isolated cytoplasmic ribosomes from Euglena gracilis and characterized the RNA components of these particles. We show here that instead of the four rRNAs (17-19 S, 25-28 S, 5.8 S and 5 S) found in typical eukaryotic ribosomes, Euglena cytoplasmic ribosomes contain 16 RNA components. Three of these Euglena rRNAs are the structural equivalents of the 17-19 S, 5.8 S and 5 S rRNAs of other eukaryotes. However, the equivalent of 25-28 S rRNA is found in Euglena as 13 separate RNA species. We demonstrate that together with 5 S and 5.8 S rRNA, these 13 RNAs are all components of the large ribosomal subunit, while a 19 S RNA is the sole RNA component of the small ribosomal subunit. Two of the 13 pieces of 25-28 S rRNA are not tightly bound to the large ribosomal subunit and are released at low (0 to 0.1 mM) magnesium ion concentrations. We present here the complete primary sequences of each of the 14 RNA components (including 5.8 S rRNA) of Euglena large subunit rRNA. Sequence comparisons and secondary structure modeling indicate that these 14 RNAs exist as a non-covalent network that together must perform the functions attributed to the covalently continuous, high molecular weight, large subunit rRNA from other systems.

Spontaneous calcium influx and its roles in differentiation of spinal neurons in culture

Stimulation of embryonic amphibian spinal neurons has been shown to produce calcium-dependent action potentials of long duration at early stages of development. These impulses become brief and sodium-dependent upon further differentiation. The neurons are now shown to exhibit spontaneous, transient elevations of intracellular calcium in culture during the early developmental period when activity produces greatest calcium influx. Removal of extracellular calcium during this period alone is sufficient to perturb differentiation, and influx through voltage-dependent calcium channels is shown to be required for standard development of neuronal phenotypes. No large changes in steady-state calcium levels occur in the cytoplasm during the maturation of cultured neurons despite a reduction of the calcium-dependent component of the impulse. Transient elevation of intracellular calcium is necessary for standard cytodifferentiation and may provide a link between electrical activity and gene expression.

Localization of cytoplasmic collagen mRNA in human aortic coarctation: mRNA enhancement in high blood pressure-induced intimal and medial thickening

Enhanced synthesis and deposition of extracellular matrix components, including collagen, contribute significantly to arteriosclerotic changes in the arterial vessel wall. We localized cells actively synthesizing collagen by hybridizing 35S-labeled RNA probes complementary to type I and III collagen mRNA with cytoplasmic mRNA in frozen sections of surgically removed aortic coarctations. These were chosen as a model for comparing mRNA levels in areas of high blood pressure-induced wall thickening and in unaffected post-stenotic areas. In situ hybridization revealed increased expression of type I and III collagen mRNA in intimal cells and in cells adjacent to the medial-adventitial border in the pre-stenotic part of the coarctation. In contrast, cells of the post-stenotic area showed only a very low signal. No immunohistologically detectable macrophages were seen in the pre-stenotic subendothelial areas where mRNA levels were enhanced. Higher collagen mRNA levels therefore occur in particular regions of high blood pressure-induced arterial wall thickening in the absence of macrophages. The results suggest that in situ hybridization is suitable for detection of locally occurring transcriptional activation of cells for collagens in the vessel wall.

Use of 1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetraacetic acid (5FBAPTA) in the measurement of free intracellular calcium in the brain by 19F-nuclear magnetic resonance spectroscopy

We have applied the 19F-nuclear magnetic resonance (NMR) calcium indicator 1,2-bis(2-amino-5-fluoro-phenoxy)ethane-N,N,N',N'-tetraacetic acid (5FBAPTA) to the measurement of the free intracellular calcium concentration [( Ca2+]i) in superfused brain slices. A mean +/- SD control value of 380 +/- 71 nM (n = 18) was obtained at 37 degrees C using 2.4 mM extracellular Ca2+. Subcellular fractionation studies using [3H]5FBAPTA showed that after loading of its tetraacetoxymethyl ester, approximately 55% was de-esterified, with the other 45% remaining as the tetraester bound to membranes. Of the de-esterified 5FBAPTA, greater than 90% was in the cytosolic fractions, with less than 1% in the mitochondria or microsomes. The NMR-visible de-esterified 5FBAPTA slowly disappeared from the tissue with a t1/2 of 4 h. A time course after loading confirmed that the calculated [Ca2+]i was constant over a 5-h period, although the scatter of individual results was +/- 20%. The [Ca2+]i was increased by a high extracellular K+ concentration ([K+]e), by a low extracellular concentration of Na+, and by the calcium ionophore A23187. On recovery from high [K+]e, the [Ca2+]i "overshot" to values lower than the original control value. The [Ca2+]i was surpisingly resistant to changes in extracellular Ca2+ concentration.

Ubiquitin in Chlamydomonas reinhardii. Distribution in the cell and effect of heat shock and photoinhibition on its conjugate pattern

Ubiquitin, a highly conserved 76-amino-acid protein, is involved in the response of many types of eukaryotic cells to stress but little is known about its role in lower plants. In the present study we have investigated the distribution of ubiquitin in the unicellular alga Chlamydomonas reinhardii as well as the effect of heat and light stress on its conjugation to cellular proteins. Immunoelectron microscopy shows that ubiquitin is located in the chloroplast, nucleus, cytoplasm, pyrenoid and on the plasma membrane. The location of ubiquitin within chloroplasts has not been observed previously. In immunoblots of whole cell extracts with an antibody to ubiquitin a prominent conjugate band with an apparent molecular mass of 29 kDa and a broad region of high-molecular-mass conjugates (apparent molecular mass greater than 45 kDa) were observed. Exposure of cells to a 41.5 degrees C heat shock in both the dark and light caused the disappearance of the 29-kDa conjugate and an increase in the high-molecular-mass conjugates. After step down to 25 degrees C the 29-kDa conjugate reappeared while the levels of high-molecular-mass conjugates decreased. In light, the recovery of the 29-kDa band was more rapid than in the dark. Photoinhibition alters the ubiquitin conjugation pattern similarly to heat shock, but to a lesser degree. These observations imply that, in Chlamydomonas, ubiquitin has a role in the chloroplast and in the response to heat and light stress.

Distribution of beta-human chorionic gonadotropin-positive cells in noncancerous gastric mucosa and in malignant gastric tumors

The authors examined the localization and behavior of beta-human chorionic gonadotropin (HCG)-positive cells in human gastric noncancerous mucosa and in gastric malignant tumors, using immunohistochemistry and the anti-beta-HCG antibody. The beta-HCG-positive cells were located mainly in the antral mucosa and were generally restricted to the neck portion of the pyloric glands, although a few were present in fundic glands of the gastric body. The beta-HCG-immunoreactive cells were found in gastric carcinomas in 53% of the 92 cases examined. These cells were observed more often in advanced carcinomas that were histologically poorly differentiated than in early carcinomas or in well-differentiated tumors, but this prevalence had no statistical significance. The presence of the beta-HCG-positive cells in the gastric carcinomas suggested no appreciable prognostic significance, even quantitatively. In the syncytiotrophoblast-like tumor cells seen in four gastric tumor samples with histologic features of a choriocarcinoma, immunoreactivity to the beta-HCG was striking. There was, however, no recognizable dominance in the number of beta-HCG-reactive cells in the noncancerous mucosa around the tumor.

Immunogold probing of platelet factor 4 in different ploidy classes of rat megakaryocytes sorted by flow cytometry

Different ploidy classes of rat megakaryocytes were sorted by flow cytometry from highly purified perfusion-fixed megakaryocyte cell suspensions prepared by sequential centrifugal elutriation and Percoll gradient centrifugation. Sorted cell populations were studied for the localization of platelet factor 4 (PF-4) probed with the monoclonal antibody 2E7 in order to clarify the relevance of PF-4 localization to the cytoplasmic and nuclear development of megakaryocytes. The relative numbers of labeled alpha granules and labeled alpha granule-related small vesicular structures (AGR-SVS) were quantitated using the gold-labeled antibody detection method and correlated with DNA content and cytoplasmic maturation in individual megakaryocytes. We determined that the stage of cytoplasmic maturation exerted a significant effect on the proportion of labeled alpha granules and labeled AGR-SVS. A significant interaction effect of stage and ploidy class resulted in the stage effect on proportion of labeled alpha granules being significant only in two of the three ploidy classes. The least mature cells present within each ploidy group exhibited PF-4 labeling mostly in SVS that were not related to alpha granules. During subsequent cytoplasmic maturation, more of the labeled SVS were seen related to alpha granules, with more of the mature alpha granules themselves becoming labeled. Polyploidization also affected the proportion of labeled AGR-SVS. Our data suggest that SVS play a role in the intramegakaryocytic transport of PF-4 into alpha granules. These data provide evidence of the complexity of megakaryocytic differentiation involving both cytoplasmic maturation and nuclear endoreduplication as reflected in PF-4 expression.

Polarization of gelsolin and actin binding protein in kidney epithelial cells

Vasopressin regulates transepithelial osmotic water permeability in the kidney collecting duct and in target cells in other tissues. In the presence of hormone, water channels are inserted into an otherwise impermeable apical plasma membrane and the apical surface of these cells is dramatically remodelled. Because cytochalasin B and D greatly reduce the response of these cells to vasopressin, actin filaments are believed to participate in the events leading to an increase in transepithelial water permeability. Modulation of the actin filamentous network requires the concerted action of specific actin regulatory proteins, and in the present study we used protein A-gold immunocytochemistry to localize two important molecules, gelsolin and actin binding protein (ABP), in epithelial cells of the kidney inner medulla. Gelsolin and, to a lesser extent, ABP were concentrated in clusters in the apical cell web of principal cells of the collecting duct. Aggregates of gold particles were often associated with the cytoplasmic side of plasma membrane regions forming surface extensions or microvilli. The basolateral plasma membrane was labeled to a much lesser extent than the apical plasma membrane. In the thin limbs of Henle, ABP was localized over the apical plasma membrane in ascending limbs, but gelsolin labeling was weak in these cells. In thin descending limbs, the pattern of labeling was completely reversed, with abundant apical gelsolin labeling but only weak ABP immunolabeling. Although the significance of the distribution of actin regulatory proteins in thin limbs is unknown, the abundance and the predominantly apical polarization of both ABP and gelsolin in principal cells of the collecting duct is consistent with a role of the actin cytoskeleton in the mechanism of vasopressin actin.

Cytologic assessment of nuclear and cytoplasmic O-linked N-acetylglucosamine distribution by using anti-streptococcal monoclonal antibodies

Recent studies have demonstrated the existence of single O-linked N-acetylglucosamine (O-GlcNAc) residues on cytoplasmic and nuclear glycoproteins. Labeled lectin and enzymatic techniques have been used to identify O-GlcNAc-bearing proteins, but no antibodies generally reactive with such O-linked GlcNAc moieties have been described. We have previously characterized monoclonal antibodies (mAbs) specific for the GlcNAc residues of streptococcal group A carbohydrate, which is composed of a polyrhamnose backbone with GlcNAc side chains. We now report that these mAbs recognize O-GlcNAc-bearing proteins. By immunofluorescence, the mAbs reacted strongly with the nuclear periphery and nucleoplasm of mammalian cells and stained the cytoplasm less intensely. The distribution was not consistent with labeling of the endoplasmic reticulum, Golgi complex, or plasma membrane. Furthermore, the staining pattern of a mutant cell line, which retains terminal GlcNAc residues on many N-linked glycans, was indistinguishable from that of wild-type cells. Nuclear and cytoplasmic staining were inhibited by free GlcNAc and were completely abolished by galactosylation of terminal GlcNAc residues. Indirect ELISA demonstrated GlcNAc- and galactosylation-inhibitable binding of the mAbs to a 65-kDa human erythrocyte cytosolic protein known to contain O-GlcNAc. Thus, these mAbs react with O-GlcNAc without apparent influence of peptide determinants, do not show detectable binding to N- or O-glycans, and, therefore, represent a valuable tool for the study of O-GlcNAc moieties. In addition, these mAbs provide the first cytologic analysis of the distribution of O-GlcNAc residues throughout the nucleus and the cytoplasm of mammalian cells.

Early and late responses to induction of rasT24 expression in Rat-1 cells

We have used a series of Rat-1 cell lines carrying a Zn-inducible human c-Ha-ras oncogene construction (MTrasT24) to evaluate the effect of varied ras oncogene expression on the expression of genes and proteins related to morphologic transformation in vitro. In response to the expression of the ras oncogene, at least two different classes of events occur. These events, referred to as 'early and late' events, are dependent on distinctively different accumulated levels of the ras oncoprotein. Relatively low levels of activated c-Ha-ras p21 protein (1.5-2.5 times the proto-oncogene level) stimulate rapid entry of quiescent (G0) cells into the cell cycle and result in increased steady state c-myc and glucose transporter mRNA levels which are detectable as early as 3-6 h after zinc addition. In contrast, morphologic transformation develops more slowly and does not appear until 72-96 h after Zn++ stimulation in cells with very low basal levels of activated p21 (MR4 cells) and 24-48 h in cells with higher basal levels (MR5 cells). These morphologic changes depend on the accumulation of significant amounts of the ras oncoprotein (greater than 4 to 5 times the proto-oncogene level) and are accompanied by large increases in the steady state mRNA levels of transin and TGF-alpha and decreases in PDGF-receptor mRNA and fibronectin protein and mRNA levels. In addition, the level of a novel cytoplasmic protein species (referred to as p29), which is stained by a monoclonal antibody for ras, is dramatically reduced in response to these levels of activated ras protein. Thus changes in morphology and gene expression induced by rasT24 occur sequentially and are quantitatively dependent on activated ras expression.

Acridine orange flow cytometric analysis of renal cell carcinoma. Clinicopathologic implications of RNA content

To explore the potential role that ribonucleic acid (RNA) content analysis may have in the assessment of primary renal cell carcinomas (RCC), biparametric flow cytometric (acridine orange) measurements for DNA/RNA were obtained on 108 fresh neoplastic specimens. RNA content was divided into low and high groups, based on the average RNA content in normal kidney controls. High RNA content was significantly correlated with aneuploidy, high proliferative index, high nuclear grade, cytoplasmic granularity, and large tumor size. No correlation was found between RNA content and patients' sex, race, and clinical stage of the carcinomas. When diploid RCCs were separately analyzed, high RNA content was correlated with high nuclear grade, large tumor size, high clinical stage, and cytoplasmic granularity. There was no correlation between RNA content and the patient's sex or race or the neoplasm's proliferative index. Of the 16 patients that relapsed (5 diploid and 11 aneuploid), four of the diploid and all 11 aneuploid neoplasms displayed high RNA content. The authors' data show that RNA may be a valuable objective and quantitative parameter in the clinicopathologic assessment of RCC.

Nuclear and "cytoplasmic" estrogen and progesterone receptors in squamous cell carcinoma of the cervix

Biopsies from 131 women with squamous cell carcinoma of the cervix diagnosed between May 1983 and July 1986 were assayed for nuclear and "cytoplasmic" estrogen receptors (NER and CER). Progesterone receptors (PR) were also assayed in 45 of these tumors. About a third of the tumors contained both CER and NER. One or the other fraction contained ER in 76.9% of cases and PR in 66.6%. Although there was a trend for those women whose tumors contained CER or NER to have a better prognosis, this was not significant. There was no evidence that PR status affected the prognosis.

Expression of platelet glycoprotein Ib by cultured human megakaryocytes: ultrastructural localization and biosynthesis

Glycoprotein Ib (GPIb), the receptor for von Willebrand factor, is a two-chain member constituent of the platelet/megakaryocytic lineage. Studies on its expression have been hampered by the difficulties in obtaining purified megakaryocytes in a sufficient number. We report a suspension liquid culture procedure that allowed isolation of more than 1 x 10(6) megakaryocytes with a purity ranging from 3% to 88% from the blood of patients with chronic myeloid leukemia, from fetal liver or from normal human bone marrow. GPIb was detected on the plasma membrane of all maturing megakaryocytes and also of promegakaryoblasts devoid of demarcation membranes. GPIb was detected on demarcation membranes of maturing megakaryocytes but was absent from all other organelles, including alpha granules. Biosynthesis of 35S-methionine labeled megakaryocytes showed that GPIb with similar electrophoretic mobility to the platelet molecule was synthesized and that it was also composed of two chains, since its molecular weight shifted in reducing conditions from 170 Kd to 145 Kd. The beta chain remained undetectable after methionine metabolic labeling, but it was immunoprecipitated after 3H-leucine metabolic labeling, confirming that this subunit is devoid of methionine. GPIb was associated with GPIX, as it is in platelets, since anti-GPIb antibodies coprecipitated a 17 Kd polypeptide.

Cytoplasmic components of natural killer cells limit the growth of Cryptococcus neoformans

Murine natural killer (NK) cell-mediated inhibition of growth of a yeast-like target cell, Cryptococcus neoformans, was completely abrogated by blocking the effector cell secretory process with monensin. Therefore, further studies were performed to determine the ability of various cytoplasmic fractions of NK cells to mediate inhibition of cryptococcal growth. Percoll-fractionated homogenates of rat LGL tumor cells demonstrated that the granule-containing fractions plus three additional sets of less dense cytoplasmic fractions displayed anti-cryptococcal activity; whereas only the cytoplasmic granule-containing fractions had cytotoxic activity against YAC-1 tumor cell and sheep erythrocyte targets. Maximal cryptococcal growth inhibition induced by LGL granules occurred after a 1 h incubation, required the presence of Ca2+ (1.0 mM) or Mg2+ (0.5 mM or 5.0 mM), and was completely abrogated in the presence of rabbit anti-LGL granule IgG. Cytolysin, the granule component which mediates tumor cell and sheep erythrocyte lysis, effectively limited the growth of cryptococci. Since Percoll gradient fractionation of the LGL homogenates demonstrated three separate peaks of anti-cryptococcal activity other than the granule peak, it is possible that the cytolysin-containing granules are not the only subcellular component of NK cells playing a role in inhibition of C. neoformans growth.

Intracellular distribution of actin in cells of the organ of Corti: a structural basis for cell shape and motility

Immunofluorescence staining and phalloidin labeling have provided localization of actin in the sensory and supporting cells of the inner ear at the light microscopic level. However, with electron microscopy, neither actin nor actin filaments have been found in the outer hair cell body. This paper describes various techniques utilized to preserve and identify cytoplasmic actin at the ultrastructural level. Post-embedding staining of Lowicryl K4M sections, pre-embedding staining of permeabilized cells of the organ of Corti, pre-embedding staining of vibratome sections, and pre-embedding staining of permeabilized dissociated cells documented the presence of actin, but each of these techniques was best suited to localize actin in specific parts of the cell. Cytoplasmic actin was labeled when isolated cells were lightly fixed and membranes were permeabilized with detergent--conditions under which the cell ultrastructure was compromised. Under conditions of optimal fixation, cytoplasmic filaments embedded in the dense granular matrix of the hair cell cytoplasm were observed.

Myxoid meningioma

A mucosubstance-rich myxoid meningioma that recurred twice is reported. This rare form of meningioma is a potential source of confusion with other myxoid neoplasms such as metastatic adenocarcinoma or chordoma. In addition to the usual stigmata of meningial cell differentiation, ultrastructural examination revealed spaces delineated by a network of cellular processes and enclosing loose granular and fibrillar material. This neoplasm is probably linked to the so-called microcystic meningioma but has an overt production of acid mucosubstance.

Continuous fluorimetric assessment of the changes in cytoplasmic calcium concentration during exposure of rat isolated myocardium to conditions of simulated ischaemia

1. The cytoplasmic calcium concentration ([Ca]c) of rat isolated atrial myocardium was assessed with the dye indo-1. Dye-loaded atria were superfused with physiological salt solution and excited with radiation at 360 nm, while epifluorescence emissions were collected simultaneously at 400 nm and 500 nm. The ratio of these emissions was used as a measure of [Ca]c. 2. Dye-loaded atria showed a phasic rise and fall in [Ca]c with each applied electrical pacing stimulus. The amplitudes of systolic increments in tension and [Ca]c were augmented by the presence of isoprenaline. 3. Atria superfused with a solution the composition of which resembled that found extracellularly in regions of ischaemia rapidly lost systolic increments in tension and [Ca]c, while end-diastolic [Ca]c and tension gradually rose. 4. The presence of lactate (20 mM) or flufenamate (5 microM) in the superfusate during simulated ischaemia aggravated the rises in both end-diastolic tension and end-diastolic [Ca]c. Inclusion in the superfusate of sulphinpyrazone (50 microM) or glucose (20 mM) protected against some of the deleterious effects of lactate seen during simulated ischaemia.

Simultaneous production of interleukin 2, interleukin 4 and interferon-gamma by activated human blood lymphocytes

The production of interleukin 2 (IL 2), IL 4 and interferon-gamma (IFN-gamma) by in vitro activated unselected human blood mononuclear cells was studied at a single-cell level. Individual lymphokine-synthesizing cells were identified by intracellular immunofluorescent staining using cytokine-specific monoclonal or polyclonal antibodies. Cultures from adult blood donors revealed a biphasic kinetic production pattern for IL 2 and IFN-gamma with peaks occurring 4-6 and 24-30 h after initiation of the cultures. Approximately 20%-40% of the lymphocytes produced IL 2 and IFN-gamma. In contrast, only 1%-3% of the lymphocytes synthesized IL 4 with maximal frequency after 6 h of culture. CD4+ as well as CD8+ T cells contributed to the synthesis of all three lymphokines studied. CD4+CD45R- T cells were the major producers of IL 2 and IL 4, while CD8+CD45R- T cells were the most common phenotype of IFN-gamma-synthesizing cells. By performing two-color immunofluorescence studies we observed that among IL 4-producing cells every second one made simultaneously IL 2 and every fourth one made IFN-gamma. Mononuclear cells from umbilical cord blood could be stimulated to make IL 2 to the same extent as cells from adult blood donors. No IL 4 production and a strikingly reduced frequency of IFN-gamma producers were noted in cell cultures from neonates. IL 2, IL 4 and IFN-gamma accumulated in the Golgi system, which resulted in a characteristic morphology of the staining, eliminating problems with evaluation of background signals.

Ca2+ binding capacity of cytoplasmic proteins from rod photoreceptors is mainly due to arrestin

Arrestin (also called S-antigen or 48-kDa protein) binds to photoexcited and phosphorylated rhodopsin and, thereby, blocks competitively the activation of transducin. Using Ca2+ titration in the presence of the indicator arsenazo III and 45Ca2+ autoradiography, we show that arrestin is a Ca2(+)-binding protein. The Ca2+ binding capacity of arresting-containing protein extracts from bovine rod outer segments is about twice as high as that of arrestin-depleted extracts. The difference in the Ca2+ binding of arrestin-containing and arrestin-depleted protein extracts was attributed to arrestin. Both, these difference-measurements of protein extracts and the measurements of purified arrestin yield dissociation constants for the Ca2+ binding of arrestin between 2 and 4 microM. The titration curves are consistent with a molar ratio of one Ca2+ binding site per arrestin. No Ca2+ binding in the micromolar range was found in extracts containing mainly transducin and cGMP-phosphodiesterase. Since arrestin is one of the most abundant proteins in rod photoreceptors occurring presumably up to millimolar concentrations in rod outer segments, we suggest that aside from its function to prevent the activation of transducin, arrestin acts probably as an intracellular Ca2+ buffer.

Characterization of site-specific polyclonal antibodies to c-erbA peptides recognizing human thyroid hormone receptors alpha 1, alpha 2, and beta and native 3,5,3'-triiodothyronine receptor, and study of tissue distribution of the antigen

The translated products of v-erbA-related cDNAs have been demonstrated to be thyroid hormone receptors, and three different forms of receptor (alpha 1, alpha 2, and beta) have been found in human tissues. We synthesized five peptides corresponding to different portions of these three receptors and raised site-specific polyclonal-antipeptide sera in rabbits. Each antibody displayed high titer and specificity for its respective antigen when tested in an enzyme-linked immunosorbent assay. Each immunoprecipitated the corresponding in vitro translated products of human c-erbA alpha 1, alpha 2, or beta. Two of the antisera were specific for beta, one for alpha 2, and one detected a sequence common to alpha 1 and alpha 2. The fifth was directed toward the DNA-binding area of the proteins and interacted with each receptor. The four antibodies against alpha 1 and beta immunoprecipitated the native thyroid hormone receptor from rat liver and caused a partial shift in the elution profile of the native receptor labeled with [125I]T3 on Sephacryl S-300 column chromatography. The antibody against alpha 2 protein did not interact with native thyroid hormone receptor from rat liver. Using the indirect immunofluorescence technique with the five antibodies, we detected immunoreactivity primarily in the nucleus of cells in several tissues. In general, there was coordinate expression of both alpha and beta receptors in each organ examined, in agreement with previous data on tissue distribution of mRNAs for human thyroid hormone receptors. These studies prove the identity of v-erbA-related gene products with native thyroid hormone receptors and the expression of both alpha and beta receptors in nuclei of human and rat tissues.

Colloidal gold labeling of intracellular ligands in dorsal root sensory neurons, visualized by scanning electron microscopy

We report a novel technique that combines high-resolution scanning electron microscopy (SEM) of intracellular structures with backscattered electron imaging (BEI) of colloidal gold-labeled intracellular ligands. Murine dorsal root ganglia were immersion-fixed, freeze-cleaved, labeled with gold complexes, and critical point-dried. Specimens were carbon-coated and viewed by BEI. They were then minimally sputter-coated with gold and previously identified cells relocated by secondary electron imaging (SEI). This permitted increased resolution of intracellular detail while gold particles remained detectable by BEI. Incubation with RNAse-gold and DNAse-gold complexes resulted in specific labeling of cytoplasm and nucleus, respectively. Immunolabeling of neurofilament (NF) and small nuclear ribonucleoproteins (snRNP) resulted in selective labeling of intracellular antigens. Nonspecific binding was abolished by use of 1% skin milk. Specifically, incubation with monoclonal anti-NF68 resulted in labeling of cytoplasm in 66% of neurons, notably of the large cells known to contain large amounts of NF. Satellite cells, which lack NF, showed low levels of background label. Human autoimmune anti-Sm serum recognizes snRNP particles, with the exception of the nucleolar U3 snRNP. Labeling with this serum resulted in specific labeling of 92% of nuclei, with only background labeling over nucleoli and cytoplasm. The results show that it is feasible to employ high-resolution SEM in conjunction with colloidal gold labeling to localize intracellular ligands in situ.

Acridine orange--RNA histofluorescence of sarcomas and small round cell tumors of childhood

Forty-nine pediatric malignant neoplasms were stained with acridine orange (AO) fluorochrome to qualitatively evaluate cytoplasmic RNA content. The application of AO as a supplementary stain in surgical pathologic diagnosis is based on the premise that specific neoplastic cell types characteristically and consistently contain few or many cytoplasmic ribosomes. Primitive tumors such as Ewing's sarcoma and primitive neuroectodermal tumors showed negative or low-intensity AO-RNA cytoplasmic staining. Differentiated sarcomas such as rhabdomyosarcomas and lymphomas exhibited moderate to strong AO-RNA cytoplasmic fluorescence. Acridine orange--RNA staining provides an easy, convenient, and inexpensive adjunct in the histopathologic differential diagnosis of sarcomas. It is particularly useful for distinguishing Ewing's sarcomas from other small round cell sarcomas of childhood.

Fine structural localization of RNA in myeloma cells detected by the enzyme-gold method

The ultrastructural localization of RNA in myeloma cells was studied by the RNase-gold method. Gold particles indicating the presence of RNA were observed in large numbers, particularly in the granular component of the nucleolus and periphery of the rough endoplasmic reticulum, but not in the Golgi area, mitochondria, intranuclear inclusion bodies, cytoplasmic inclusion bodies, dense bodies, or cisternae of the rough endoplasmic reticulum. In the nuclear chromatin and nucleolus, gold particles were more numerous as these structures were less mature. They were found in larger numbers also in the cytoplasm of immature cells. In plasma cells from patients with macroglobulinemia, gold particles were fewer than in myeloma cells of multiple myeloma, but there was no difference in their distribution pattern.

Herpes simplex virus activates expression of a cellular gene by specific binding to the cell surface

The herpes simplex virus (HSV) type 1 mutant ts1204 attaches to the cell surface at 38.5 degrees but fails to penetrate the plasma membrane. A striking feature of human fetal lung cells infected with ts1204 at 38.5 degrees was the presence of enhanced amounts of a 56,000 molecular weight host protein, p56. Studies with protein and RNA synthesis inhibitors suggested that binding of the mutant virus to cells activated expression of the cellular gene encoding p56 and not an intermediary protein. Evidence presented in this paper supports the idea that p56 is induced by a specific interaction between ts1204 virions and the cell surface.

Spinal cord neurofibrillary tangles of Guamanian amyotrophic lateral sclerosis and parkinsonism-dementia complex: an immunohistochemical study

We studied the topographic distribution and immunohistochemical characteristics of spinal cord neurofibrillary tangles (NFTs) in 6 patients with Guamanian amyotrophic lateral sclerosis (ALS) and 6 patients with parkinsonismdementia complex (PD) on Guam, using antibodies to tau protein and ubiquitin. The NFTs were immunoreactive with both antibodies, but staining for tau was more pronounced. As identified by this reactivity, all the Guamanian ALS and PD cases examined showed spinal cord NFTs. The posterior horn had the most and the anterior horn the least. In the posterior horn the NFTs were located mainly in the marginal areas. Large anterior horn cells showed few, if any, NFTs. In addition to perikaryal NFTs, we observed tau-reactive neurites. Our results provide evidence that spinal cord NFTs are not uncommon in Guamanian ALS and PD on Guam and that they are more numerous than previously found with conventional methods.

A possible approach to enrich cDNA yields with full-length molecules

Newcastle disease virus (NDV)-specific hemagglutinin-neuraminidase (HN) mRNAs were used as the model templates for cDNA synthesis. Polyadenylated RNAs were isolated from the particulate fraction of cytoplasmic extracts of NDV-infected cells rather than from nonfractionated extracts. The approach is based on earlier findings that eucaryotic mRNAs are present in cytoplasmic extracts in the form of ribonucleoproteins (mRNPs) rather than as free nucleic acids. The idea of the approach was to separate mRNPs from cell sap RNases prior to RNA extraction in order to minimize partial enzymatic hydrolysis of mRNAs. The presence of the 5' terminus (mRNA sense) in cDNAs synthesized was considered as an indication for the suitability of mRNA templates for cDNA synthesis. The cDNAs were synthesized and cloned in lambda gt10 phage. About 300 phages carrying the HN-specific inserts have been identified among 50,000 recombinants, and nine of them were analyzed for the presence of the HN 5' terminus. It was found that the termini are present in all the clones analyzed. The result is in an agreement with the expectation that removal of cell sap prior to RNA extraction significantly increases the suitability of RNA templates for cDNA synthesis.

Cytoplasmic pH of Dictyostelium discoideum amebae during early development: identification of two cell subpopulations before the aggregation stage

Development of the cellular slime mold Dictyostelium discoideum is initiated by the removal of nutrients, and results in formation of a mature fruiting body composed of two cell types, the stalk and spore cells. A considerable body of evidence supports the hypothesis that cytoplasmic pH may be an essential regulator of the choice to differentiate in either the prestalk or prespore pathway. We have devised methods for measurement and analysis of intracellular pH in developing Dictyostelium amebae in order to assess directly the potential role of cytoplasmic pH in regulating the pathway of differentiation. The intracellular pH of single D. discoideum amebae during development and in intact slugs has been measured using the pH-sensitive indicator pyranine in a low light level microspectrofluorometer. We have used the ATP-mediated loading method to introduce pyranine into these cells. Cells loaded by the ATP method appear healthy, have no detectable defects in development, and exhibit a similar population distribution of intracellular pH to those loaded by sonication. The intracellular pH of populations comprised of single amebae was found to undergo a transient acidification during development resulting in a bimodal distribution of intracellular pH. The subpopulations were characterized by fitting two gaussian distributions to the data. The number of cells in the acidic intracellular pH subpopulation reached a maximum 4 h after initiation of development, and had returned to a low level by 7 h of development. In addition, a random sample of single amebae within a slug had a median intracellular pH of 7.2, nearly identical to the median pH (7.19) of similarly treated vegetative cells. No gradient of intracellular pH along the anterior to posterior axis of the slug was detected. Our data demonstrate the existence of two distinct subpopulations of cells before the aggregation stage of development in Dictyostelium, and offers support for the hypothesis that changes in intracellular pH contribute to development in D. discoideum.

The function of the vaccinia hemagglutinin in the proteolytic activation of infectivity

The vaccinia virus hemagglutinin (HA) has specific affinity for the structural protein, VP37K. The nature of this affinity and its relationship to the function of the HA were analyzed using HA mutants. The VP37K reactive site of the HA molecule is located in its transmembrane region, and the vaccinia virus HA associates with the viral particle via the VP37K-HA affinity. The viruses possessing an HA with fusion inhibitor activity were largely of the low infectivity form, whereas the viruses that associated mutant HAs defective in the activity were of the high infectivity form. D1 mutant virus does not produce HA. When it was incubated with the HA of the IHD-J strain, the HA associated with the virus particle. The HA-loaded D1 mutant virus acquired a high affinity not only for chick erythrocytes but also for KB and Vero cells. At the same time, the infectivity for Vero cells was decreased. The original high infectivity was recovered by treatment with trypsin. The virion-associated vaccinia HA has two functions; the HA protects the infectivity of the virus by the fusion inhibitor activity and exhibits affinity against host cells. Vaccinia virus first adsorbs to the cell via HA, and then proteolysis of the HA activates the second adsorption site which seems to be the fusogenic site of the virus. Proteolytic activation represents removal of the fusion inhibitor activity of the HA.

Intrinsic pituitary interleukin-1 beta is induced by bacterial lipopolysaccharide

Using a specific antiserum recognizing recombinant rat interleukin-1 beta (IL-1 beta), immunoreactive material was localized to cytoplasmic granules in anterior pituitary endocrine cells and colocalized with TSH in thyrotropes. Authenticity was established by Northern blot hybridization using a specific rat IL-1 beta cRNA probe, revealing a 1.8-kilobase mRNA identical to that in the spleen. The marked increase in anterior pituitary IL-1 beta message after the administration of bacterial lipopolysaccharide, raises the possibility that IL-1 beta may be involved in paracrine or autocrine regulation of pituitary function during infectious challenge.

The 56-59-kilodalton protein identified in untransformed steroid receptor complexes is a unique protein that exists in cytosol in a complex with both the 70- and 90-kilodalton heat shock proteins

It has previously been shown that 9S, untransformed progestin, estrogen, androgen, and glucocorticoid receptor complexes in rabbit uterine and liver cytosols contain a 59-kDa protein [Tai, P. K., Maeda, Y., Nakao, K., Wakim, N. G., Duhring, J. L., & Faber, L. E. (1986) Biochemistry 25, 5269-5275]. In this work we show that the monoclonal antibody KN 382/EC1 raised against the rabbit 59-kDa protein reacts with 9S, untransformed glucocorticoid receptor complexes in cytosol prepared from human IM-9 lymphocytes but not with 4S salt-transformed receptors. The human protein recognized by the EC1 antibody is a 56-kDa protein (p56) of moderate abundance located predominantly in the cytoplasm by indirect immunofluorescence. There are at least six isomorphs of p56 by two-dimensional gel analysis. N-Terminal sequencing (20 amino acids) shows that p56 is a unique human protein. When p56 is immunoadsorbed from IM-9 cell cytosol, both the 70- and 90-kDa heat shock proteins are coadsorbed in an immune-specific manner. Neither heat shock protein reacts directly with the EC1 antibody. We conclude that p56 exists in cytosol in a higher order complex containing hsp70 and hsp90, both of which in turn have been found to be associated with untransformed steroid receptors.

Immunohistochemical localization of the glucocorticoid receptor in pancreatic beta-cells of the rat

We used a monoclonal antibody against an epitope located in the N-terminal moiety of the rat glucocorticoid receptor to identify the glucocorticoid receptor-containing cells in the rat pancreas. Monospecific polyclonal antisera against insulin, glucagon, somatostatin, and amylase were applied to serial sections in colocalization studies to identify the respective endocrine and exocrine cells. Glucocorticoid receptor immunoreactivity was exclusively present in nuclei and cytoplasm of the beta-cells of pancreatic islets. Western blots using the glucocorticoid receptor antibody resulted in identical 94K immunoreactive proteins in both liver and pancreas. After adrenalectomy, the glucocorticoid receptor immunoreactivity of beta-cells decreased significantly. A computer-assisted method of semiquantitative evaluation of the glucocorticoid receptor immunoreactivity demonstrated a significant decrease in the staining intensity of the beta-cells by 23.5% and in that of insulin antibodies by 10.4%, while amylase immunoreactivity was only slightly decreased. Serum levels of corticosterone determined by RIA decreased from 225 micrograms/ml in sham-operated animals to 55 micrograms/ml in animals 14 days after adrenalectomy, while the tissue content of amylase decreased by 45%. The immunohistochemical findings give circumstantial evidence of the presence of glucocorticoid receptor in beta-cells. We interpret our data as indicating an indirect effect of glucocorticoids on amylase synthesis via a glucocorticoid-insulin-exocrine cell pathway.

Detection of intracellular expression and secretion of interferon-gamma at the single-cell level after activation of human T cells with tetanus toxoid in vitro

Activation of T cells results in intracellular expression and secretion of cytokines such as interferon (IFN)-gamma. Here we have used three different assays for determination of IFN-gamma in tetanus toxoid- or mitogen-activated human T cell cultures. Two of these assays [intracytoplasmic immunofluorescence and enzyme-linked immuno spot assay (ELISPOT)] determined the expression and secretion of IFN-gamma at the single-cell level while the third assay enzyme-linked immunosorbent assay (ELISA) measured IFN-gamma secreted into the culture supernatant. Comparison of all three tests revealed a good correlation between the ELISPOT assay and the ELISA, whereas expression of intracellular IFN-gamma showed a qualitative but not a quantitative correlation with the latter. Both the immunospot assay and the immunofluorescence may be used to detect approximate numbers of specific T cells even when present at low frequencies. With the use of the immunospot assay antigen-specific T cells could be detected even in the absence of detectable IFN-gamma in the culture supernatants. However, the ELISA assay should be more convenient for screening large clinical material.

Conservation of a cytoplasmic carboxy-terminal domain of connexin 43, a gap junctional protein, in mammal heart and brain

According to the sequence of connexin 43, a cardiac gap junctional protein, the domain contained within residues 314-322 is located 60 amino acids away from the carboxy-terminus. Antibodies raised to a peptide corresponding to this domain label a unique 43-kD protein on immunoblots of both purified gap junctions and whole extracts from rat heart. Immunofluorescence investigations carried out on mammal heart sections reveal a pattern consistent with the known distribution of intercalated discs. Immunogold labeling performed with ultrahin frozen sections of rat heart or partially purified rat heart gap junctions demonstrate that antigenic determinants are associated exclusively with the cytoplasmic surfaces of gap junctions. The antibodies were shown to cross-react with a 43-kD protein on immunoblots of whole extracts from human, mouse and guinea pig heart. However, no labeling was seen when heart of lower vertebrates such as chicken, frog and trout, was investigated. These results, confirmed by immunofluorescence investigations, were interpreted as a loss of antigenic determinants due to sequence polymorphism of cardiac connexin 43. Proteins of Mr 43 and 41 kD, immunologically related to cardiac connexin 43, were detected in immunoblots of mouse and rat brain whole extracts. mRNAs, homologous to those of cardiac connexin 43 and of the same size (3.0 kb), are also present in brain. Immunofluorescence investigations with primary cultures of unpermeabilized and permeabilized mouse neural cells showed that the antigenic determinants recognized by the antibodies specific for connexin 43 are cytoplasmic and that the labeling observed between clustered flat cells, is punctate, as expected for gap junctions. Double labeling experiments demonstrated that the immunoreactivity is associated with GFAP-positive cells, that is to say, astrocytes.

A major glycoprotein of the nuclear pore complex is a membrane-spanning polypeptide with a large lumenal domain and a small cytoplasmic tail

One of a small number of polypeptides of the nuclear pore complex that have been identified is a major glycoprotein called gp210. Since it is very resistant to chemical extractions from membranes, gp210 was suggested to be integrated into nuclear membranes. In this study we have determined the membrane topology of this protein by biochemical and immunological approaches. We found that limited proteolysis of isolated nuclear envelopes with papain released a 200 kd water-soluble fragment of gp210 containing concanavalin A-reactive carbohydrate. Immunogold electron microscopy with a monoclonal antibody showed that this domain is localized on the lumenal side of nuclear membranes at pore complexes. Anti-peptide antibodies against two sequences near the C-terminus of gp210 were used to map possible membrane spanning and cytoplasmically disposed regions of this protein. From analysis of the protease sensitivity of these epitopes in sealed membrane vesicles, we determined that gp210 contains a small cytoplasmic tail and only a single membrane-spanning region. Thus, gp210 is a transmembrane protein with most of its mass, including the carbohydrate, located in the perinuclear space. This topology suggests that gp210 is involved primarily in structural organization of the pore complex, for which it may provide a membrane attachment site.

Distribution of fodrin in the keratinocyte in vivo and in vitro

Distribution of fodrin in the keratinocyte, both in vivo and in vitro, was examined by immunofluorescence microscopy. In the rat epidermis in vivo, fodrin was localized in the cell periphery of the spinous layer of all the skins studied. In only the basal layer of the thick skin, however, fodrin was seen intensely in the cytoplasm. As in vitro keratinocytes, a mouse cell line (Pam 212) cultured in low (0.06 mM) as well as standard (1.87 mM) Ca2+ was examined. In low Ca2+, fodrin was observed throughout the cytoplasm without marked accumulation irrespective of the cell density. The cytoplasmic labeling in low Ca2+ looked filamentous and became aggregated when cells were treated with cytochalasin B; at least some of the aggregates coexisted with those of F-actin. In contrast, fodrin distribution was not affected with colchicine. On the other hand, in standard Ca2+, the protein became concentrated along the cell periphery and less conspicuous in the cytoplasm as the cells reached confluency. When cells were transferred from low to standard Ca2+, the distribution of fodrin changed accordingly within 180 min. The present results indicate that fodrin in the keratinocyte is likely to be associated with actin filaments and that it takes two different ways of distribution both in vivo and in vitro. The peripheral and the cytoplasmic labeling of in vivo and in vitro cells are likely to correspond. It may be that fodrin changes its localization according to the cell's proliferative activity.

Interleukin 2 production by a marmoset B cell line

Several B cell lines constitutively secreting interleukin (IL) 2 were derived from the Epstein-Barr virus-positive marmoset B cell line, B95-8. A representative line, KRC-18, was cloned by limiting dilution and found to be 40% surface IgM+, 60% cytoplasmic IgM+, greater than 95% DR+, weakly Tac+ and devoid of T cell, monocyte and NK cell surface antigens. Supernatant from KRC-18 cells supported the long-term growth of an IL 2-dependent murine T cell line, HT-2, and contained 7-8 units/ml of IL 2 activity when compared to recombinant IL 2. The supernatant was fractionated by Sephadex G-75 gel filtration, and maximal proliferation of HT-2 cells was supported by the 20-22-kDa column fraction. The proliferative response of HT-2 cells to KRC-18 supernatant was inhibited by monoclonal antibodies to human IL 2 or the murine IL 2 receptor in a dose-dependent manner, suggesting that the KRC-18 IL 2 has epitopes that are similar to human IL 2, and that its activity is mediated through binding to the IL 2 receptor of the target cell line. When KRC-18 cells were analyzed for cytoplasmic IL 2, greater than 90% of the cells contained intracellular IL 2 in amounts equivalent to, or greater than, mitogen-activated T cells. These data indicate that certain B lineage cell lines are capable of IL 2 synthesis and secretion.

A Hoechst H33258 agarose plate assay for the estimation of nanogram DNA levels without RNA interference: applications in PCR and in estimations of plasmid and cytoplasmic DNA

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