Characterization of potassium channels in respiratory cells. I. General properties.

Potassium channels present in the basolateral membrane of respiratory epithelial cells play an important role in the process of chloride secretion. Utilizing the patch clamp technique, we examined human cultured respiratory epithelial cells derived from patients with cystic fibrosis (CF) and normals individual (N) for the existence of and for the properties of K+ channels. We obtained qualitatively and quantitatively identical results for both preparations (CF and N). K+ channels were spontaneously present in cell attached patches. The channels showed burst appearance with rapid flickering within the bursts. When the pipette was filled with 145 mmol/l KCl, a mean conductance of 131 +/- 25 pS (n = 15) was read from the I/V-curve at a clamp voltage (Vc) of 0 mV. After excision, the conductance read from the I/V-curve at Vc = 0 mV was 212 +/- 11 pS (Pipette: 145 mmol/l KCl, bath: 145 mmol/l NaCl) (n = 61). With NaCl in the pipette and KCl in the bath, a similar conductance was obtained (g = 210 pS; n = 2). When both, pipette and bath contained KCl, the conductance was increased to 302 +/- 19 (n = 7). The channel was highly selective for potassium over sodium: PK + /PNa + greater than 40. The channel open probability was only slightly voltage dependent i.e. the open probability increased slightly with depolarisation. For most of the channels one open time constant (to = 6.3 +/- 1.6 ms; n = 22) and one closed time constant (tc = 1.8 +/- 0.3 ms; n = 21) was obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Histochemical analysis of nasal polyps.

In the last 3 years, 86 nasal polyps from 76 patients were examined. Special attention was paid to the group of recurrent nasal polyps, which redeveloped from 2 to 17 times. Histological analysis was performed concerning the eosinophils, mast cells, acid and neutral mucopolysaccharides, acetylcholinesterase and fluorescence on monoamines. Macroscopically, nasal mucosa in 53 patients was considered for control purposes. The comparison was made and the results of the examination reviewed.

Prostaglandins, leukotrienes, and other arachidonic acid metabolites in nasal polyps and nasal mucosa.

Prostaglandins (PGs) and leukotrienes (LTs) are known to play an important role in allergic inflammatory reactions. The triad of aspirin sensitivity, nasal polyposis, and asthma led us to suspect that PGs, LTs and other arachidonic acid metabolites may be involved in the pathogenesis of nasal polyps. The purpose of this study was to determine arachidonic acid metabolites and to measure concentrations of PGs and LTs in nasal polyps and nasal mucosa. Samples of nasal polyps and nasal mucosa were obtained at the time of polypectomies and nasal procedures. Metabolites of arachidonic acid in tissue were determined by incubation of tissue-homogenates with 14C-arachidonic acid and analyses with thin-layer chromatography and high performance liquid chromatography (HPLC). Levels of PGE2, 6-keto-PGF1 alpha, thromboxane (Tx)B2, 15-hydroxyeicosatetraenoic acid (HETE), LTC4, LTB4 were measured by radioimmunoassay. The predominant arachidonic acid metabolite in both nasal polyps and mucosa with 15-HETE. The HPLC analysis showed that the predominant metabolite in nasal polyp was 15-HETE, especially in polyps from aspirin sensitive patients. Levels of 15-HETE and PGE2 were higher in polyps from patients with a history of allergy than from nonallergic patients. Levels of LTC4 and LTB4 in nasal polyps were determined. The findings of this study will help to explain biochemical basis of the pathogenesis of aspirin-sensitive nasal polyps and to develop better medical treatment for them.

Localization of human eosinophil granule major basic protein, eosinophil cationic protein, and eosinophil-derived neurotoxin by immunoelectron microscopy.

By utilizing the colloidal gold particle technique, we localized eosinophil granule major basic protein, eosinophil cationic protein (ECP), and eosinophil-derived neurotoxin (EDN) in human nasal polyp sections by immunoelectron microscopy. Sections stained with affinity chromatography purified rabbit anti-human major basic protein, and subsequently with gold colloidal particle-goat anti-rabbit IgG, showed gold particles predominantly within granule cores, and not within other eosinophil organelles, plasma cells, mast cells, lymphocytes, or neutrophils. Sections stained with anti-ECP or anti-EDN showed gold particles concentrated over the granule matrix with fewer particles centrally. Control sections treated with preimmunization sera showed no staining of cells or organelles. These results verify the localization of major basic protein to the crystalloid core of the human eosinophil granule and show that ECP and EDN reside in the granule matrix. This technique provides a means of accurately locating the sites of major basic protein, ECP, and EDN deposition and thus of identifying eosinophil degranulation patterns in human disease.

Detection of ABO(H) blood group antigens: a study in tissue culture.

The association between malignant transformation and the loss of ABO(H) blood group antigens was documented by several authors. Most of the work was done on paraffin sections, though a small portion was performed on fresh frozen tissues. We suggest that the specific red cell adherance (SRCA) test can be applied to tissues cultivated in tissue culture for determination of malignant transformation. This study supports this assumption.

Partial purification and characterization of the tissue plasminogen activator in nasal mucosa and nasal polyp.

Tissue plasminogen activator was partially purified from the inferior turbinate and nasal polyp, and its biochemical properties were investigated. Similar TPA peak positions were seen in the gel filtration chromatography of both tissues, and the molecular weight was approximately 65,000, which was comparable to TPA of pig heart (55,000-60,000). Activity of TPA from inferior turbinate was higher than that from nasal polyp. TPA from both tissues was completely inhibited by trans-aminomethyl cyclohexane carboxylic acid, dithiothreitol, and diisopropylfluorophosphate and had similar inhibition profiles to TPA from pig heart. All these findings indicate that TPA from both tissues is undoubtedly a plasminogen-activating enzyme and serine-type protease and would be biochemically identical.

Free histamine in nasal polyp fluid.

Nasal polyp fluid was extracted from 52 patients to evaluate histamine levels and compare them with the corresponding serum levels. Large but variable amounts of histamine were found in polyp fluid (124-7600 ng/ml) which was between twenty and a thousand times the serum level. There was no significant difference between the polyp histamine levels in patients with a history of asthma, aspirin hypersensitivity, hay fever and positive skin tests.

Histamine and its release from nasal polyps: preliminary communication.

Two hundred consecutive patients admitted for polypectomy had no evidence of an increased incidence of allergic disorders. Mast cell degranulation was found on transmission electron microscopy and this resulted in considerable quantities of histamine in polyp extracellular fluid (124-7300 ng/ml). RAST levels of allergen-specific IgE to house-dust mite and mixed-grass pollens were raised in 4 out of 28 cases in polyp fluid, and in only one matched serum. In vitro challenge of polyp tissue with allergen extract and anti-IgE suggested an IgE-mediated response in only 4 of 36 patients.

Analysis of glycoproteins from nasal polyps and papillomas by affinity chromatography.

Glycoproteins were isolated from the particulate fraction of four nasal polyps and three nasal papillomas by affinity chromatography on lectins conjugated with agarose (Concanavalin A [Con A], wheat germ agglutinin [WGA], Ricinus communis agglutinin [RCA], peanut agglutinin [PNA], and Dolichos biflorus agglutinin [DBA]). The glycoprotein mixtures so isolated were then analyzed by sodium dodecyl sulfate gel electrophoresis. Glycoprotein profiles of nasal polyps were similar to each other, but were distinctively different from those of nasal papillomas. Binding sites for Con A, WGA, and RCA isolated from nasal papillomas contained intense bands with a molecular weight less than 15,000 daltons, which were absent in nasal polyps. The major component of PNA-binding sites of nasal polyps is of a molecular weight of 65,000 daltons, which was not detected in nasal papillomas.

Clinical symptoms, free histamine and IgE in patients with nasal polyposis.

29 adult patients with nasal polyps were studied. The clinical symptoms and atopic profile were compared with both the level of histamine and IgE found in polyp fluid. The high concentration of free histamine found in polyp fluid was probably pathological, and local IgE was present in greater amounts than expected by simple diffusion. There was no evidence that clinical hypersensitivity is associated with higher concentrations of IgE and histamine in polyp fluid; it is possible that mechanisms other than an IgE-mediated response could cause degranulation of mast cells in nasal polyps.

Histamine, norepinephrine and serotonin content of nasal polyps.

Histamine, norepinephrine and serotonin were assayed and localized by fluorescence histochemistry in normal mucosa and nasal polyps because of their possible role in the development of inflammation and edema. Histamine was present in greater concentration in nasal polyps than in normal mucosa. Norepinephrine was present primarily in the base of nasal polyps and in greater concentration than in normal mucosa. Patients with aspirin sensitivity and asthma had much lower histamine concentrations in their nasal polyps than all other patients with nasal polyps. A proposal for a possible mechanism of formation of nasal polyps based on vascular and inflammatory mechanisms and incorporative roles for histamine and norepinephrine is presented.