[The digestive barrier functions of the enzymatic systems of the normal small intestine and in pathology]

The fact that the enzymes splitting food nutrients, those of protein nature in particular, not only in the epithelial cells of the small bowel, but in the lower structures of the intestinal wall, i.e. in the stromal and muscle serous layers, is shown for the first time. They are integral parts of the intestinal enzymatic barrier that protects the internal medium of the body from penetration of proteins and peptides. The activities of the enzymes which are present in the epithelial, stromal, and muscle serous layers have been demonstrated to be substantially changed in disorders (immobilization in the presence of starvation, surgical interventions into the small bowel). It is suggested that examining the functions of the postepithelial enzymatic barrier along with those of the epithelial and immunological ones will provide a deeper insight into some certain disorders of the alimentary tract.

Drug-abbreviated infections and development of immunity against Trichostrongylus colubriformis in sheep

A protective immune response without liveweight loss can be induced in sheep against T. colubriformis but results depend on the anthelmintic used and duration of immunizing infections. More than 90% protection was achieved in sheep immunized by three 15- or 7-day oxfendazole abbreviated infections or three 21-day nonabbreviated infections. Only 41% protection was induced by 3-day oxfendazole abbreviated infections. Significantly higher worm burden and faecal egg counts were present after challenge in sheep immunized by 7-day levamizole abbreviated infections compared to 7-day oxfendazole abbreviated infection. Liveweight gains of sheep immunized by 15- and 7-day abbreviated infections were not significantly different than non infected controls. Liveweight loss seemed to be associated with high activity of mucus peroxidase and high numbers of eosinophils in the intestinal lumen. High parasite numbers seemed to be associated with low activity of alkaline phosphatase in mucus. Mucus peroxidase, arylsulphatase, larval migration inhibition of mucus, mucus or serum antibody against L3 excretory/secretory antigen or somatic L3, L4 and adult antigen were not associated with protection.

Effects of MR889, a cyclic thiolic neutrophil elastase inhibitor, on rheologic properties of mucus

MR889 is a synthetic inhibitor of human neutrophil elastase with potential in clinical conditions characterized by a high load of this proteolytic enzyme, mainly chronic obstructive pulmonary disease. On the basis of its mechanism of inhibition, it has been suggested that MR889, upon reaction with elastase, would generate new free thiol groups. The aim of this study was to investigate whether MR889, upon reaction with elastase, may modify rheologic properties, i.e. apparent viscosity and elasticity, of both human sputum and porcine stomach mucus, in ex-vivo and in vitro experiments. MR889 10(-4) M alone had no effect on rheologic properties of samples, whereas an agent with free thiol group, n-acetylcysteine 10(-4) M reduced both viscosity and elasticity. MR889 10(-4) M upon reaction with elastase 0.03 nMol (giving 83% of elastase inhibition) had no effect on rheologic properties of samples, whereas upon reaction with elastase 0.15 nMol (49% inhibition) yielded a marked decrease in viscosity. This result would suggest that MR889, in the presence of a high load of elastase, may acquire direct mucus modifying capacity, likely because of its greater utilization upon reaction with the enzyme.

Development of an avidin-biotin competitive inhibition assay and validation of its use for the quantitation of human intervertebral disc serine proteinase inhibitory proteins

A simple convenient method has been developed for the quantitation of serine proteinase inhibitors (SPIs) in tissue extracts. The method is based on the competitive binding to trypsin and chymotrypsin immobilized using glutaraldehyde on 96-well microtiter plate wells of native SPIs and a biotinylated secretory proteinase inhibitor (SLPI) standard. The bound SLPI standard was visualized using an avidin-alkaline phosphatase conjugate and inhibition curves were determined using absorbancy measurements at 405 nm. The standard assay had a range between 0.02 and 1 microgram SLPI/well and a lower detection limit of 20 ng SLPI/well; an improved microassay had a detection limit of 2 ng SLPI/well. Only active free inhibitor was detected in the assay since denatured and/or enzyme-inhibitor complexes did not bind to the plates. A range of SPI species was demonstrable in human bronchial mucus and intervertebral disc SPI samples using this technique. Quantitation of SPI levels in a number of intervertebral disc samples indicated that the SPIs were depleted in degenerate discs compared to nondegenerate discs (P less than 0.05, n = 12). Since the immobilized trypsin and chymotrypsin microplates used in this assay may be prepared in advance (and are stable at 4 degrees C for at least 1 month) the remaining two steps of the assay (the inhibition step and visualization) may be completed in 2-3 h; thus the assay is simple, convenient, and fast. All reagents (other than the biotinylated SLPI standard) are readily available commercially, and in principle the assay could be adapted to other systems provided defined biotinylated standards were available.

[The adsorption of pancreatic enzymes by the small intestine as one of the mechanisms coupling cavitary and parietal intestinal digestion]

Intraduodenal administration of inactivated intestinal mucus and erythrocytes abolished the inhibiting effect of pancreatine on the pancreatic secretion in dogs. The enzymes fixed by the duodenum mucose seem to inhibit the pancreatic secretion.

[The enzymatic barrier of the small intestine]

The small intestine's barrier functions are reviewed. The data on mechanical (passive) and active protective systems of the organism against various antigens, toxic substances and proteins, is presented. An important role of these protective systems as an enzyme apparatus of epithelial and postepithelial layers of the small intestine's mucose, is shown.

The proteinase: mucus proteinase inhibitor binding stoichiometry

In the nanomolar enzyme and inhibitor concentration range, 1 mol of mucus proteinase inhibitor (MPI) inhibits 1 mol of neutrophil elastase, cathepsin G, trypsin, and chymotrypsin. In the micromolar concentration range, the enzyme:inhibitor binding stoichiometry is still 1:1 for elastase but shifts to 2:1 for the three other proteinases. These data could be confirmed by three nonenzymatic methods: (i) fluorescence anisotropy measurements of mixtures of proteinases with 5-dimethylaminonaphthalene-1-sulfonylated or fluoresceinylated MPI, (ii) absorption spectrocospy of fluorescein-MPI-proteinase complexes isolated by gel filtration, (iii) analytical ultracentrifugation which showed that the molecular mass of the MPI-chymotrypsin complex is 56 kDa, whereas that of the MPI-elastase complex is 39 kDa. The binary MPI-elastase complex is unable to inhibit trypsin or cathepsin G. On the other hand, 1 mol of elastase displaces 2 mol of trypsin or cathepsin G from their ternary complexes with MPI.

[The trypsin activity in the chyme and parietal layer of the mucus in experimental exclusion of the Brunner's gland section of the duodenum in rats]

The duodenal glands secretion into intestine was excluded by surgical ablation or ligation of Brunner's glands region. The trypsin activity in chyme and adherent mucous layer was reduced following these manipulations. Possible reasons for changes established are discussed.

The effects of calcitonin gene-related peptide on submucosal gland secretion and epithelial albumin transport in the ferret trachea in vitro

1. We have examined the effect of calcitonin gene-related peptide (CGRP) on basal mucus volume, lysozyme and albumin outputs from the ferret whole trachea in vitro, and on the outputs produced by methacholine and substance P (SP). We have also examined the effect of inhibiting neutral enkephalinase with thiorphan on the responses to CGRP. 2. CGRP (1-100 nM) produced small concentration-dependent increases in basal mucus volume, lysozyme and albumin outputs. These effect of CGRP were enhanced by thiorphan. The increases in basal outputs with CGRP and the potentiation by thiorphan were considerably less than previously observed with SP and neurokinin A (NKA). CGRP had no significant effect on potential difference (PD) across the trachea. 3. CGRP produced a concentration-dependent inhibition of methacholine- and SP-induced lysozyme output but a concentration-dependent increase in methacholine- and SP-induced albumin output. The effects of CGRP on methacholine-induced lysozyme and albumin outputs were enhanced by thiorphan. CGRP weakly inhibited methacholine-induced mucus volume output and weakly enhanced SP-induced mucus volume output. 4. Thus, CGRP weakly stimulates basal serous cell secretion and epithelial albumin transport, but does not alter epithelial integrity. CGRP inhibits the serous cell secretion due to methacholine or SP, but potentiates the epithelial albumin transport produced by these agents. The interaction between CGRP and other sensory neuropeptides or muscarinic agonists on airway submucosal glands and epithelium may be important in the normal airway and in inflammatory airway diseases where release of sensory neuropeptides is enhanced.

[The digestive function of the supraepithelial mucosal layer of the small intestine]

The results of biochemical estimation of the activity of intestinal proper and pancreatic enzymes in enteral contents, mucous layer and homogenate of small intestine's membrane suggest an important role of supraepithelial mucous layer in actualization of final stages of the food hydrolysis. The term "parietal digestion" is suggested for designation of a sum of hydrolytic processes in the layer of mucus.

Lysosomal proteases and protease inhibitors in nasal allergy and non-atopic sinusitis

Patterns of protease activity and levels of protease inhibitors were analyzed in both nasal secretions and tissue extracts from patients with nasal allergy and non-atopic sinusitis to investigate the role of proteases in the inflammatory reaction. Protease activity was measured using specific methyl-coumaryl-7-amide substrates. The pattern of protease activity in the nasal secretions of chronic sinusitis patients was similar to that in neutrophil lysate and quite different from that in plasma. Both gluthatione activation testing and inhibition testing using synthetic inhibitors revealed that the majority of proteases in both secretions and tissues are lysosomal thiol proteases such as cathepsins B and L. Neutrophilic elastase is also a major protease in nasal secretions. In acute sinusitis, both protease activity and inhibitor levels were very high, suggesting an interaction between proteases and inhibitors. Cathepsin B and B-like thiol proteases appear to play a key role in prolonging chronic inflammation against the healing process, due to their resistance to plasma inhibitors and the shortage of thiol protease inhibitors. Protease activity in the secretions of nasal allergy patients was very weak, and the reaction between proteases and inhibitors appeared to be weak.

Mucus proteinase inhibitor: a fast-acting inhibitor of leucocyte elastase

Human mucus proteinase inhibitor is a fast-acting inhibitor of human leucocyte elastase (EC 3.4.21.37) and forms a stable, complex with this enzyme. At physiological ionic strength and temperature and in the presence of 10 mg/ml albumin, the kinetic constants characterizing the interaction between elastase and the non-degraded inhibitor are: kass = 6.4.10(6) M-1.s-1, kdiss = 2.3.10(-3) s-1, Ki = 3.10(-10) M. The partially degraded inhibitor isolated by chymotrypsin-Sepharose chromatography inhibits elastase with similar efficiency, suggesting that if partial proteolysis of the inhibitor occurs in vivo, the latter may still act as a potent antielastase. Mucus proteinase inhibitor therefore plays a physiological antielastase function in upper respiratory tract secretions, since it inhibits elastase with a delay time of 150 ms and behaves like an irreversible inhibitor.

Sulfation in vitro of mucus glycoprotein by submandibular salivary gland: effects of prostaglandin and acetylsalicylic acid

Enzymatic sulfation of mucus glycoprotein by rat submandibular salivary gland and the effect of prostaglandin and acetylsalicylic acid on this process were investigated in vitro. The sulfotransferase enzyme which catalyzes the transfer of sulfate ester group from 3'-phosphoadenosine-5'-phosphosulfate to submandibular gland mucus glycoprotein has been located in the detergent extracts of Golgi-rich membrane fraction of the gland. Optimum enzyme activity was obtained at pH 6.8 with 0.5% Triton X-100, 25 mM NaF and 4 mM MgCl2, using the desulfated glycoprotein. The enzyme was also capable of sulfation of the intact mucus glycoprotein, but the acceptor capacity of such glycoprotein was 68% lower. The apparent Km of the submandibular gland sulfotransferase for salivary mucus glycoprotein was 11.1 microM. The 35S-labeled glycoprotein product of the enzyme reaction gave in CsCl density gradient a 35S-labeled peak which coincided with that of the glycoprotein. This glycoprotein upon reductive beta-elimination yielded several acidic 35S-labeled oligosaccharide alditols which accounted for 75% of the 35S-labeled glycoprotein label. Based on the analytical data, the two most abundant oligosaccharides were identified as sulfated tri- and pentasaccharides. The submandibular gland sulfotransferase activity was stimulated by 16,16-dimethyl prostaglandin E2 and inhibited by acetylsalicylic acid. The rate of enhancement of the glycoprotein sulfation was proportional to the concentration of prostaglandin up to 2.10(-5) M, at which point a 31% increase in sulfation was attained. The inhibition of the glycoprotein sulfation by acetylsalicylic acid was proportional to the drug concentration up to 2.5.10(-4) M at which concentration a 48% reduction in the sulfotransferase activity occurred. The apparent Ki value for sulfation of salivary mucus glycoprotein in presence of acetylsalicylic acid was 58.9 microM. The results suggest that prostaglandins may play a role in salivary mucin sulfation and that this process is sensitive to such nonsteroidal anti-inflammatory agents as acetylsalicylic acid.

The effects of peptide histidine isoleucine and neuropeptide Y on mucus volume output from the ferret trachea

1. The effects of peptide histidine isoleucine (PHI) and neuropeptide Y (NPY) were examined on the mucus volume output produced by methacholine and phenylephrine in the ferret whole trachea in vitro. 2. Sustained application of methacholine (5 microM) or phenylephrine (20 microM) produced a maintained volume output of mucus from the trachea. Both these agonists also increased the output of lysozyme (a marker for serous cell secretion). 3. PHI inhibited the maintained mucus volume output produced by methacholine but had no effect on that due to phenylephrine. The output of lysozyme produced by methacholine or phenylephrine was not significantly changed by PHI. 4. NPY enhanced the volume output of mucus produced by methacholine or phenylephrine; however, the rate of output of lysozyme in mucus produced by both agonists was reduced by NPY. 5. We suggest that PHI has no effect on serous cell secretion but inhibits secretion from another source, possibly mucous cells. NPY inhibits serous cell secretion but has a stronger stimulant action on secretion from another source, again possibly mucous cells. 6. PHI and NPY may be important physiological modulators of mucus volume output in the ferret trachea.

[Fucose and other neutral hexoses in the feces of patients with nonspecific ulcerative colitis]

Secretion of glycoproteins with protective mucus of large intestine was studied by means of estimation of the carbohydrate components in feces of patients with unspecific ulcerous colitis. A decrease in daily excretion with feces of glycoproteins and glycopeptides was detected in these patients as well as in the patients with chronic pancreatitis. Under conditions of unspecific ulcerous colitis distinct from chronic pancreatitis content of fucoglycoproteins, main chemical protectors of gastrointestinal tract, was primarily decreased. The defect of large intestine mucus might be responsible for impairment of barrier function of the intestinal mucose and to contribute to ulcer development.

Degradation by bacterial enzymes of colonic mucus from normal subjects and patients with inflammatory bowel disease: the role of sialic acid metabolism and the detection of a novel O-acetylsialic acid esterase

1. The activities of enzymes degrading human colonic mucin were examined in faecal specimens from healthy subjects and patients with inflammatory bowel disease. 2. The activity of sialidase was measured using a new physiological substrate related to mucus glycoproteins. In addition, acylneuraminate pyruvate-lyase (N-acetylneuraminate lyase; EC 4.1.3.3.) and a novel O-acetylsialic acid esterase (sialate O-acetylesterase; EC 3.1.1.53) were detected. 3. The O-acetylsialic acid esterase activity was readily detectable in partially purified fractions after Sephadex G-100 chromatography. 4. Patients with inflammatory bowel disease showed significant increases in acylneuraminate pyruvate-lyase and proteinase activity but sialidase activity did not differ from normal. The activity of these enzymes in neutrophils could not account for the differences observed.

Enzymatic sulphation of mucus glycoprotein in rat sublingual salivary gland

Sulphotransferase activity catalysing the transfer of sulphate ester group from 3'-phosphoadenosine-5'-phosphosulphate to salivary mucus glycoprotein was located in detergent extracts of the Golgi-rich membrane fraction of rat sublingual salivary glands. Optimum enzyme activity was obtained with 0.5 per cent Triton X-100, 20 mM NaF and 2 mM MgCl2, at pH 6.8, using desulphated sublingual salivary mucus glycoprotein. The enzyme was equally capable of sulphation of the proteolytically degraded and desulphated glycoprotein, whereas the acceptor capacity of intact salivary mucus glycoprotein was about four times lower. The Golgi enzyme preparation also catalysed the sulphation of galactosylceramide. However, the sulphation of mucus glycoprotein was not affected by the presence of this glycolipid, suggesting that the sulphotransferase involved in mucin sulphation is different from that responsible for the synthesis of galactosylceramide sulphate. The apparent Km of the sublingual-gland mucus glycoprotein sulphotransferase for salivary mucin was 7.7 microM. The 35S-labelled glycoprotein product of the enzyme reaction gave, in CsCl density gradient, a band in which the 35S label coincided with the glycoprotein. Alkaline borohydride reductive cleavage of this glycoprotein released the label into the reduced acidic oligosaccharide fraction. Upon thin-layer chromatography, two [35S]-oligosaccharides were detected. These were identified as penta- and heptasaccharides, each bearing a labelled sulphate ester group on the terminal N-acetylglucosamine residue. Based on the results of chemical and enzymatic analyses of the intact and desulphated compounds the following structures for these oligosaccharides are suggested: SO3----GlcNAc beta----Gal beta----GlcNAc beta----Gal beta----GlcNAc beta----(NeuAc----)GalNAc-ol and SO3----GlcNAc beta----Gal beta----GlcNAc beta----(NeuAc----)GalNAc-ol.

Biodegradability of inhaled organic particles in patients with chronic bronchitis

2 h after the inhalation of monodispersed 99mTc-labeled autologous spherocytes and of commercial human albumin microspheres (HAM), 7 patients with chronic bronchitis underwent bronchofibroscopy. The fate of organic particles along the tracheobronchial tree was verified by scanning electron microscopy and the proteolytic activity (trypsin and PZ peptidase) in mucus samples was assessed. Significant proteolytic activity was detected in bronchial secretions. Thereafter in vitro digestion of labeled spherocytes and HAM was verified after exposure to increasing concentrations of trypsin. While in vitro a similar time-course of tryptic digestion of both particles was observed, in vivo spherocytes seem to be less vulnerable to enzymatic digestion. These findings add another unexpected variable, which may influence the reproducibility of radioaerosol lung mucociliary clearance measurements, and improve its standardization.

[Effects of iodine-enriched egg (IE-egg) on nasal allergy: basic and clinical investigations]

The effect of iodine-enriched egg (IE-egg) on nasal allergy was investigated using an experimental allergic model. In addition, the effect of IE-egg was investigated using patients with yearly nasal allergy. IE-egg could suppress the leakage of pontamine sky blue dye in the experimental allergic model. beta-Glucuronidase activity in the perfusate was suppressed with the ingestion of IE-egg. The symptoms of the patients with yearly nasal allergy were mitigated by the ingestion of IE-egg. beta-Glucuronidase activity in the pituita of nasal allergic patients tended to be decreased.

Proteolytic activity and serum protease inhibitors in nasal secretions from adult patients with common colds

Proteolytic activity and concentrations of serum protease inhibitors were measured in nasal secretions collected from 14 adult patients (6 males and 8 females) with common colds. Elastase concentration and fibrinolytic activity increased about three days after the onset of the colds, and there was a significant correlation between both values (p less than 0.01). Trypsin-like protease activity was very low. Of all serum protease inhibitors, inter-alpha-trypsin inhibitor could not be detected, and alpha 2-macroglobulin could be detected in only two cases. Variation of alpha 1-antitrypsin value was very similar to that of alpha 1-antichymotrypsin, and there was a significant correlation between alpha 1-antitrypsin and elastase (p less than 0.001). Phoretic patterns of crossed immuneelectrophoresis revealed the presence of alpha 1-antitrypsin-protease complex. alpha-protease inhibitors are major serum protease inhibitors in nasal secretions of persons with colds, and inhibit excess proteolytic activity of serine proteases. This protection is considered to be one of the major factors in preventing irreversible mucosal change.

Benzo(a)pyrene hydroxylase activity in human bronchial mucus

Sputum collected from patients with respiratory diseases were examined for presence of benzo(a)pyrene hydroxylase (BPH) activity. The human bronchial mucus used in these studies had significant capability to metabolize benzo(a)pyrene. Clarification of the sputum by agents such as N-acetylcysteine or pancreatin in presence of antibiotics was found to be essential for the detection of BPH activity. In vitro incubation of the clarified human bronchial mucus with benzoflavone caused inhibition, while 7,8-dimethyl-benzanthracene induced BPH enzyme activity.

Mucus glycoprotein fatty acyltransferase in patients with cystic fibrosis: effect on the glycoprotein viscosity

The presence of an acyltransferase activity which catalyzes the transfer of palmitic acid from palmitoyl coenzyme A to mucus glycoprotein has been demonstrated in the microsomal fraction of human rectal mucosa. The activity of this enzyme in the mucosa of patients with cystic fibrosis (CF) was found to be 3.5 times higher than that from normal individuals. The CF mucus glycoprotein in comparison to that of normal contained 1.3 times more associated lipids and 6 times more covalently bound fatty acids. The viscosity of the intact CF glycoprotein was 1.8 times higher than that of normal glycoprotein. Extraction of associated lipids led to 3-fold drop in the viscosity of CF glycoprotein and 5-fold drop in the case of normal glycoprotein. Further loss in the viscosity occurred following removal of the covalently bound fatty acids. The viscosity of such modified CF mucus glycoprotein was only about 10% higher than that of similarly treated normal glycoprotein.

Faecal mucus degrading glycosidases in ulcerative colitis and Crohn's disease

Because the normal faecal flora includes bacteria which can produce mucus-digesting glycosidases, it follows that increased digestion of colonic mucus by these bacterial enzymes could be important in the pathogenesis of ulcerative colitis. Faecal activities of potential mucus-degrading glycosidases have therefore been assayed in samples from patients with inflammatory bowel disease and normal controls. The enzymes alpha-D-galactosidase, beta-D-galactosidase, beta-NAc-D-glucosaminidase alpha-L-fucosidase and neuraminidase were assayed. Considerable glycosidase activity was present in most faecal samples. Similar activities of all the enzymes assayed were found in faeces from patients with ulcerative colitis, Crohn's disease and normal controls and there was no significant correlation with disease activity. These results imply that relapse of ulcerative colitis is not initiated by increased degradation of colonic mucus by faecal glycosidases but do not exclude a role for bacterial mucus degradation in the pathogenesis of ulcerative colitis.

The N-terminal sequence of antileukoprotease isolated from bronchial secretion

Antileukoprotease (ALP) was isolated from bronchial secretion. The amino acid composition as well as the N-terminal sequence were determined. No homology with other low molecular weight proteinase inhibitors was found.

Histochemical and biochemical studies of carbonic anhydrase activity in the opercular epithelium of the euryhaline teleost, Fundulus heteroclitus

Carbonic anhydrase (CAH) activity was biochemically measured and histochemically localized (at both the light and electron microscope levels) in isolated opercular membranes from teleost fish, Fundulus heteroclitus, adapted to freshwater (FW), seawater (SW), and double-strength seawater (2 x SW). The normal morphology of this membrane showed that its epithelial portion consisted of five cell types: (1) chloride cells, which have been previously implicated as responsible for the active chloride transport across the epithelium; (2) mucous cells; (3) pavement cells, which formed the major portion of the free epithelial surface; (4) supportive cells, which had an abundance of intermediate (10 nm)-type filaments suggesting a structural role for these cells; and (5) vesicular cells, which were characterized by various types of membrane-bound vesicles, including lysosomes, and numerous free ribosomes. Vesicular cells may be stem cells and/or endocrine cells. Hansson's histochemical method for CAH revealed cobalt sulfide reaction product confined to the following structures in fish from each environment: (1) chloride cells: throughout the cytoplasm and some nuclear staining; (2) mucous cells: throughout the cytoplasm, some nuclear staining, and some in mucous granules; (3) vesicular cells: confined to lysosomes, some of the vesicles, and nucleoli; (4) a small portion of the intracellular space between adjacent vesicular cells and supportive cells; and (5) supportive cells: in nucleoli and occasionally in larger membrane-bound lysosomelike structures. Acetazolamide (10(-5) M) and potassium cyanate (KCNO) (10(-1) M) in Hansson's incubation medium completely inhibited the formation of reaction product. Biochemical determination of CAH activity on vascularly perfused, isolated opercular membranes showed no statistically significant difference in enzyme activity between environmental groups. The following units of activity/mg opercular membrane protein were measured: FW: 0.63 +/- 0.02; SW: 0.43 +/- 0.08; 2 x SW: 0.64 +/- 0.09.

Placental alkaline phosphatase in nonmalignant human cervix

At least three loci determine human alkaline phosphatases [orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1]: one coding for the placental form of the enzyme; at least one coding for the intestinal forms; and at least one for the liver, bone, and kidney forms. It is generally believed that the locus determining the placental form is, in the normal individual, expressed only in placenta. However, ectopic or aberrant expression of this locus occurs in certain malignancies of other tissues and in cell lines, such as HeLa, derived from malignancies. We have examined by thermostability, inhibition, and immunologic studies the alkaline phosphatases in endocervix, cervical mucus, and endometrium from nonpregnant women with no evidence of malignancy. It was found that on the average about 18% of the alkaline phosphatase activity in endocervix and in cervical mucus is placental in type, the remainder being of the liver/bone/kidney type. The quantity of the placental enzyme is, however, low and amounts to only about 0.5% of the amount in normal term placenta. In endometrium all the alkaline phosphatase activity was of the liver/bone/kidney type. Thus the placental alkaline phosphatase locus is expressed in nonmalignant endocervix. The result is of some significance in connection with the widely held view that the expression of placental alkaline phosphatase in certain malignancies (including cervical malignancy) is due to derepression of a locus for a fetal enzyme protein normally repressed in adult tissues.

[Cytochemical demonstration of cyclic nucleotide phosphodiesterases in the taste buds of Testudo horsefieldi turtles upon exposure to flavored substances]

Phosphodiesterase of cyclic nucleotides was found cytochemically on the plasmat membrane of the apical part and microvillar projections of the receptor cells and, to a lower extent on the membranes of microvilli of the supporting cells as well as on the mucose granules of the taste buds of the tortoise Testudo horsfieldi. Administration of 1/250 M quinine chloride to the surface of the tongue results in the disappearance of the products of the enzymic reaction from the surface of the mentioned membranes. After application of 0.25 M surcrose, the reaction products are found within the apical part of the receptor cells on the membranes of the plain endoplasmic reticulum. Possible role of cyclic nucleotides in taste reception is discussed.

The importance of lysozyme for the viscosity of sputum from patients with chronic obstructive lung disease

Addition of lysozyme (1 g/l) to sputum from patients with chronic obstructive lung disease increased the viscosity of the material significantly. The effect was prevented by addition of salt (LiCl) in the high concentration (0.25 mol/l). The sole addition of salt decreased the viscosity of native sputum. These results together with our earlier [5] studies of the interaction between the positively charged lysozyme and the negatively charged mucin molecules in model systems, indicate that lysozyme acts as a cross-linking agent in mucus by an electrostatic mechanism. Lysozyme is thus, at least partly, responsible for building up a macromolecular network giving mucus its characteristic gel-like properties.

[The isoenzyme pattern of lactate-dehydrogenase in nasal secretions (author's transl)]

In the present study, the qualitative and quantitative isoenzyme pattern of lactate-dehydrogenase (LDH) in nasal secretions of 52 probands without disease in the nose is investigated electrophoretically. It was found that the LDH-isoenzyme pattern in nasal secretions does not only differ clearly from the distribution of LDH-isoenzymes is serum of the same probands but is characterized especially by a high percentage of LDH 3- and LDH 4-fractions; this corresponds to the monomeres H2M2 and HM3. These results differ completely from any other enzymatic pattern in the human organism. The results clearly indicate that LDH in nasal secretion is a product of the mucous membranes and does not originate from the serum by means of transsudation into the nasal secretion.

Preliminary studies on the mucus secretion of the wood wasp, Sirex noctilio F. I. Physicochemical and biochemical properties

The major component of S. noctilio mucus appears to be a protein-polysaccharide complex with probable molecular weight in the range 60000-100000. In aqueous solution the macromolecule undergoes slow spontaneous disaggregation to yield dialysable subunits of molecular weight 2000-6000 which retain all the physiological activity of the whole mucus. More rapid disaggregation is brought about by treatment of solutions with moderate concentrations of NaCl, KC1 OR CaCl2, or by heating. The native mucus contains amylase, esterase, phenoloxidase and proteolytic enzyme activities, and it is suggested that these enzymes may be responsible, at least in part, for the "natural" disaggregation process.

[Rate of transudation of the mucous membranes by testing the enzymes of the intermediary metabolism in the secretion of patients with different internal diseases (author's transl)]

In patients with increased levels of GOT, GPT, CPK, LDH, SP and AP in serum, the activities of these enzymes in nasal mucus are determined. Even in cases with extreme increase of activity in serum, the enzyme-activities in nasal mucus are normal. From this we concluded first, that the enzymes in nasal mucus are specific products of the intermediary metabolism of the mucous membranes and secondly, that the rate of transsudation of serum proteins by the nasal mucous membrane therefore is very low in physiological state.

[Metabolic enzymes in human nasal mucus under physiological and pathophysiological conditions of the mucous membrane (author's transl)]

In the human nasal mucus several enzymes of the intermediary metabolism are present. Due to secreted albumin the enzyme-levels are determined in different diseases of the upper respiratory tract. It is possible to differentiate viral rhinitis from bacterial or allergic or atrophic rhinitis by a significant increase of the activities of GOT, LDH and CPK.

[Mucous membrane specific protease inhibitors in bronchial mucus in severe chronic obstructive bronchitis and in alpha 1-antitrypsin deficiency syndrome]

In the bronchial mucus of 40 patients with chronic obstructive airway diseases we measured proteolytic activities, the total protein concentrations, alpha1-antitrypsin, alpha1-antichymotrypsin, and the free and bound proteinase inhibitors together with the total proteinase inhibition against trypsin and chymotrypsin. Without exception we always found free proteinase inhibitors together with proteolytic activities. The free-to-bound inhibitor rate was approximately 1:1 alpha1-Antitrypsin and alpha1-antichymotrypsin was measured in sputum only in very low concentrations. One patient with alpha1-anti-trypsin deficiency had no alpha1-antitrypsin, but high concentrations of total proteinase inhibitor-free and bound being in the same relation - in his bronchial mucus. In the alveolar part of the lung, the humoral proteinase inhibitors were effective. In the bronchial part of the lung the specific mucosal inhibitors had the decided importance. The proteinase inhibition of the mucosa-specific inhibitors is probably of great importance for the pathogenesis of airway obstruction, while the humoral proteinase inhibitors are responsible for the pathogenesis of emphysema.