Jukka Leinonen

University of Oulu, Uleoborg, Oulu, Finland

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Publications (11)30.58 Total impact

  • Jukka Leinonen · Seppo Parkkila
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    ABSTRACT: Secreted carbonic anhydrase isoenzyme VI (CA VI) is the only secretory isoenzyme of the 16 α-carbonic anhydrase isoforms in mammals. CA VI is secreted by the mammary, parotid, submandibular, posterior lingual, lacrimal, nasal, tracheobronchial, and esophageal glands. In addition, it has been found in the oral mucosa, serum, hair follicle, ameloblasts, and embryonic fibroblasts. The catalytic activity of CA VI is moderate but well adjusted for neutralizing pH in secretory fluids. CA VI also activates calmodulin-dependent cAMP phosphodiesterase and has been proposed to act as a growth factor in taste receptor cells and small intestine. The investigations on CA VI-deficient mice have associated CA VI with a multitude of biological processes. This chapter summarizes the recent progress in understanding the functions of CA VI.
    No preview · Article · Dec 2015
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    ABSTRACT: Carbonic anhydrase VI (CAVI) is the only secreted isozyme of the α-carbonic anhydrase family, which catalyzes the reversible reaction \( {\text{CO}}_{2} + {\text{H}}_{2} {\text{O}} \Leftrightarrow {\text{HCO}}_{3}^{ - } + {\text{H}}^{ + } \). It appears that CAVI protects teeth and gastrointestinal mucosa by neutralizing excess acidity. However, the evidence for this physiological function is limited, and CAVI may have additional functions that have yet to be discovered. To explore the functions of CAVI more fully, we generated Car6 −/− mice and analyzed Car6 −/− mutant phenotypes. We also examined transcriptomic responses to CAVI deficiency in the submandibular gland, stomach, and duodenum of Car6 −/− mice. Car6 −/− mice were viable and fertile and had a normal life span. Histological analyses indicated a greater number of lymphoid follicles in the small intestinal Peyer’s patches. A total of 94, 56, and 127 genes were up- or down-regulated in the submandibular gland, stomach, and duodenum of Car6 −/− mice, respectively. The functional clustering of differentially expressed genes revealed a number of altered biological processes. In the duodenum, the significantly affected biological pathways included the immune system process and retinol metabolic processes. The response to oxidative stress and brown fat cell differentiation changed remarkably in the submandibular gland. Notably, the submandibular gland, stomach, and duodenum shared one important transcriptional susceptibility pathway: catabolic process. Real-time PCR confirmed an altered expression in 14 of the 16 selected genes. The generation and of Car6 −/− mice and examination of the effects of CAVI deficiency on gene transcription have revealed several affected clusters of biological processes, which implicate CAVI in catabolic processes and the immune system response.
    Full-text · Article · Jun 2011 · Transgenic Research
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    ABSTRACT: Carbonic anhydrase VI (CAVI) is the only secreted isozyme of the α-carbonic anhydrase family, which catalyzes the reversible reaction $$ {\text{CO}}_{2} + {\text{H}}_{2} {\text{O}} \Leftrightarrow {\text{HCO}}_{3}^{ - } + {\text{H}}^{ + } $$. It appears that CAVI protects teeth and gastrointestinal mucosa by neutralizing excess acidity. However, the evidence for this physiological function is limited, and CAVI may have additional functions that have yet to be discovered. To explore the functions of CAVI more fully, we generated Car6 −/− mice and analyzed Car6 −/− mutant phenotypes. We also examined transcriptomic responses to CAVI deficiency in the submandibular gland, stomach, and duodenum of Car6 −/− mice. Car6 −/− mice were viable and fertile and had a normal life span. Histological analyses indicated a greater number of lymphoid follicles in the small intestinal Peyer’s patches. A total of 94, 56, and 127 genes were up- or down-regulated in the submandibular gland, stomach, and duodenum of Car6 −/− mice, respectively. The functional clustering of differentially expressed genes revealed a number of altered biological processes. In the duodenum, the significantly affected biological pathways included the immune system process and retinol metabolic processes. The response to oxidative stress and brown fat cell differentiation changed remarkably in the submandibular gland. Notably, the submandibular gland, stomach, and duodenum shared one important transcriptional susceptibility pathway: catabolic process. Real-time PCR confirmed an altered expression in 14 of the 16 selected genes. The generation and of Car6 −/− mice and examination of the effects of CAVI deficiency on gene transcription have revealed several affected clusters of biological processes, which implicate CAVI in catabolic processes and the immune system response.
    Full-text · Article · Feb 2011 · Transgenic Research
  • K. M. SAARI M.D · J. LEINONEN · E. AINE
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    ABSTRACT: To study the effect of prolonged irrigation in the treatment of chemical eye injuries we reviewed the case records of 172 patients. Most of the patients were men in working age. The injury was caused by acid in 57 patients (33%). Of the acid burns, 28 were due to AIV solution commonly used in agriculture in Finland, and 27 were due to inorganic acids. Alkaline burns occurred in 64 (37%) patients including 33 cases with natrium hydroxide and 20 cases with mortar and cement burns. Other chemicals including organic solvents and surfactants caused the eye burn in 51 (30%) cases. Fifty three patients mostly with alkaline and acid burns were treated with prolonged irrigation with one liter of physiological saline using intravenous delivery system during 1–2 hours. The extent of damage was smaller, the visual outcome better, and the duration of treatment at the hospital and absence from work were shorter in patients treated with prolonged irrigation than without such treatment.
    No preview · Article · May 2009 · Acta ophthalmologica
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    ABSTRACT: The molecular mechanism governing the regulated secretion of most exocrine tissues remains elusive, although VAMP8/endobrevin has recently been shown to be the major vesicular SNARE (v-SNARE) of zymogen granules of pancreatic exocrine acinar cells. In this article, we have characterized the role of VAMP8 in the entire exocrine system. Immunohistochemical studies showed that VAMP8 is expressed in all examined exocrine tissues such as salivary glands, lacrimal (tear) glands, sweat glands, sebaceous glands, mammary glands, and the prostate. Severe anomalies were observed in the salivary and lacrimal glands of VAMP8-null mice. Mutant salivary glands accumulated amylase and carbonic anhydrase VI. Electron microscopy revealed an accumulation of secretory granules in the acinar cells of mutant parotid and lacrimal glands. Pilocarpine-stimulated secretion of saliva proteins was compromised in the absence of VAMP8. Protein aggregates were observed in mutant lacrimal glands. VAMP8 may interact with syntaxin 4 and SNAP-23. These results suggest that VAMP8 may act as a v-SNARE for regulated secretion of the entire exocrine system.
    Full-text · Article · Apr 2007 · Molecular Biology of the Cell
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    ABSTRACT: The carbonic anhydrases (CAs) participate in the maintenance of pH homeostasis in various tissues and biological fluids of the human body by catalysing the reversible reaction CO2+ H2O ⇌ HCO3−+ H+ (Davenport & Fisher, 1938; Davenport, 1939; Maren, 1967). Carbonic anhydrase isoenzyme VI (CA VI) is the only secretory isoenzyme of the mammalian CA gene family. It is exclusively expressed in the serous acinar cells of the parotid and submandibular glands, from where it is secreted into the saliva. In this review, we will discuss recent advances in research focused on the physiological role of salivary CA VI in the oral cavity and upper alimentary canal.
    Full-text · Article · Sep 2004 · The Journal of Physiology
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    ABSTRACT: Carbonic anhydrase isoenzyme VI (CA VI), which is transported in high concentrations in saliva and milk into the alimentary tract, is an important element of mucosal protection in the upper alimentary tract. Like alimentary tract mucosa, the respiratory tract mucosa is also exposed to heavy microbial, physical, and chemical stress. The protective and renewal-promoting factors present in the surface mucus of the respiratory tract are mainly produced by the seromucous tracheobronchial glands. Here we studied the secretion of CA VI by these glands in adult and developing rats using immunohistochemical techniques. The serous acinar and duct cells of the tracheobronchial glands stained for CA VI. The presence of the enzyme also in the duct content indicates its active secretion into the surface mucus. CA VI was also visible in the secretory cells and at the base of the ciliated cells of the tracheobronchial surface epithelium. Moreover, the Clara cells of the bronchiolar surface epithelium stained for CA VI. These findings are consistent with the hypothesis that CA VI has a mucosa-protective role not only in the gastrointestinal tract but also in the respiratory tract, where CA VI may act as a pivotal pH neutralizer and growth factor.
    Preview · Article · Sep 2004 · Journal of Histochemistry and Cytochemistry
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    ABSTRACT: In addition to essential nutrients, human milk contains several classes of bioactive factors such as enzymes, hormones, and growth factors, many of which are implicated in infantile growth and development. Secretory carbonic anhydrase isoenzyme VI (CA VI) has been identified earlier as an essential component of mammalian saliva, and we demonstrate here by using biochemical and immunohistochemical techniques that it is also an elementary component of milk. The 42-kDa glycopolypeptide purified from human milk in CA inhibitor affinity chromatography shared 100% homology with salivary CA VI in the protein sequence analysis (40% coverage), and its digestion with PNGase F resulted in a polypeptide backbone similar in size to salivary CA VI. Quantification of CA VI in milk by using a time-resolved immunofluorometric assay revealed an approximately eight-times-higher concentration in human colostrum than in mature milk, the latter corresponding to the levels previously detected in human saliva. The high concentration in the colostrum, in particular its functional and structural stability in an acidic milieu, and its growth-supporting role in the taste buds suggest that milk CA VI is an essential factor in normal growth and development of the infant alimentary tract.
    Full-text · Article · Oct 2001 · Proceedings of the National Academy of Sciences
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    ABSTRACT: Salivary carbonic anhydrase VI (CA VI) appears to contribute to taste function by protecting taste receptor cells (TRCs) from apoptosis. The serous von Ebner's glands locating in the posterior tongue deliver their saliva into the bottom of the trenches surrounding the TRC-rich circumvallate and foliate papillae. Because these glands deliver their saliva directly into the immediate vicinity of TRCs, we investigated whether CA VI is secreted by the von Ebner's glands, using immunochemical techniques. The immunohistochemical results showed that CA VI is present in the serous acinar cells, ductal cells, and ductal content of von Ebner's glands and in the demilune and ductal cells plus ductal content of rat lingual mucous glands. More importantly, CA VI was also detected in taste buds and in the taste pores. Western blotting of saliva collected from the orifices of human von Ebner's glands and CAs purified from rat von Ebner's glands confirmed that CA VI is expressed in these glands and secreted to the bottom of the trenches surrounding the circumvallate and foliate papillae. These findings are consistent with the hypothesis that locally secreted CA VI is implicated in the paracrine modulation of taste function and TRC apoptosis. (J Histochem Cytochem 49:657-662, 2001)
    Preview · Article · Jun 2001 · Journal of Histochemistry and Cytochemistry
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    J Keski-Säntti · T Parkkila · J Leinonen · P Leinonen
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    ABSTRACT: The role of the charging cranes is important for the effective and reliable production at a steel mill. A broken crane affects to production and safety. Several checkups and terms to follow are done for safety and for usability of the crane. Continuous condition monitoring measurements for cranes has been quite problematic to carry out for travelling and for the dusty environment and large temperature variations. New technology at the wireless data transfer, sensors, and measurement systems can change the situation. This research focuses on testing MEMS sensors, antennas, and Nanonet TRX transmission technique for condition monitoring purposes. Also one of the targets is ability to use these methods at the prognostication. The testing of MEMS technology based acceleration sensors includes calibration and comparison with normally used sensors. Promising results have been achieved. Also usability of different kind of antennas at the charging crane was tested in a casting bay. Six antenna types were checked in different parts of the bay. The results of the studies gave us the ability to utilize measurement system with FPGA-SoC computing platform. Main advantages of the system are the price of the components which enables either cheaper condition monitoring systems or increasing the amount of measurements. As a part of PROGNOS project these measurements are also going to be utilized at the prognostics of charging crane.
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