Biomedical subjects

L K Korhonen

Publications and source records attributed to L K Korhonen.

At least 19 recordsLinked to original sources

PubMed2003

Gas chromatographic-mass spectrometric detection of 2- and 3-hydroxy fatty acids as methyl esters from soil, sediment and biofilm.

Hydroxy fatty acids (OH-FAs) can be used in the characterization of microbial communities, especially Gram-negative bacteria. We prepared methyl esters of 2- and 3-OH-FAs from the lipid extraction residue of soil, sediment, and biofilm samples without further purification or derivatization of hydroxyl groups. OH-FA methyl esters were analyzed using a gas chromatograph equipped with a mass selective detector (GC-MS). The ions followed in MS were m/z 103 for 3-OH-FAs and m/z 90 and M-59 for 2-OH-FAs. The rapid determination of 3- and 2-OH-FAs concomitantly with phospholipid fatty acids provided more detailed information on the microbial communities present in soil, sediment, and drinking water biofilm.

Biofilms↗

PubMed2003

Microbial community structure in biofilms and water of a drinking water distribution system determined by lipid biomarkers.

The development of microbial communities in biofilms of a drinking water distribution system was monitored, and compared to the microbial communities in water. The microbial communities were studied by phospholipid fatty acid (PLFA) profiles. In drinking water samples the most common PLFAs, with the proportion of 60.9%, were monoenoic fatty acids, such as 16:1omega7c and 18:1omega7c, indicating high abundance of gram-negative bacteria. Instead, in biofilm samples saturated fatty acids, such as 16:0 and 18:0, indicating general biomass, accounted for 54.9-78.4% of the total PLFAs. The proportions of monoenoic fatty acids in biofilm increased from 11.5% to 31.2% with water aging from 22 h to 62 h in the distribution system. In conclusion, water aging affected the structure of microbial communities in biofilms, and the microbes in water differed from those in biofilms. These differences might also reflect the differences in the physiological state of the microbes, which is influenced by water chemistry and by the growth environment, i.e. water or biofilm.

Bacteria↗

PubMed2001

Soft deposits, the key site for microbial growth in drinking water distribution networks.

In this project we studied the microbiological quality of soft pipeline deposits removed from drinking water distribution networks during mechanical cleaning. Drinking water and deposit samples were collected from 16 drinking water distribution networks located at eight towns in different parts of Finland. Soft pipeline deposits were found to be the key site for microbial growth in the distribution networks. The microbial numbers in the soft deposits were significantly higher than numbers in running water. The highest microbial numbers were detected in the main deposit pushed ahead by the first swab. The deposits contained high numbers of heterotrophic bacteria, actinomycetes and fungi. Also coliform bacteria were often isolated from deposit samples. Manganese and copper in the deposits correlated negatively with the numbers of heterotrophic bacteria. After a year, the viable microbial numbers in the new deposits were almost as high as in the old deposits before the first mechanical cleaning. The bacterial biomass production was higher in the new than in the old deposits.

Bacteria↗

PubMed1991

Survival of Escherichia coli and Campylobacter jejuni in untreated and filtered lake water.

The survival of Campylobacter jejuni and Escherichia coli in lake water was studied using viable counts. Escherichia coli survived better than C. jejuni in all the test conditions studied. Both the species survived better in filtered than in untreated water. This suggests that predation and/or competition for nutrients affect the survival of both the species in an aquatic environment. Campylobacter jejuni survived less well in filtered autoclaved water and in 0.9% NaCl than in filtered water without autoclaving. The lack of some essential nutrients, which may be degraded by autoclaving, might explain these results.

Campylobacter jejuni↗

PubMed1991

Comparison of the survival of Campylobacter jejuni and Campylobacter coli in culturable form in surface water.

Six Campylobacter jejuni and six Campylobacter coli strains were isolated from cows and pigs, and their survival in lake water was compared by viable counts. Campylobacter jejuni survived longer in culturable form than C. coli in untreated and membrane-filtered water both at 4 and 20 degrees C. This difference in survival time may be a reason why C. jejuni is generally isolated from surface waters more frequently than C. coli. Both species survived better in filtered than in untreated water. This suggests that predation and competition for nutrients affect the survival of both Campylobacter species in the aquatic environment.

Animals↗

PubMed1990

Comparison of some enrichment broths and growth media for the isolation of thermophilic campylobacters from surface water samples.

Three different enrichment broths and two selective growth media were compared for isolating thermophilic campylobacters by combined membrane filtration and enrichment techniques from surface waters of different physical, chemical and bacteriological characteristics. Fifty-two strains of campylobacters were isolated from total of 1668 cultures. The various broth/medium combinations did not affect the dominance of C. jejuni over C. coli (total 49 C. jejuni and three C. coli). The most efficient combinations of enrichment broth and growth media were either Oosterom broth/blood-free charcoal-cefoperazone-deoxycholate agar (CCDA) medium or blood-free charcoal-cefoperazone-deoxycholate (CCD) broth/CCDA medium. Modified Preston broth (sheep blood instead of horse blood) with either of the growth media gave significantly lower yields although it suppressed efficiently the growth of contaminants. Skirrow medium had lower selectivity than CCDA medium and gave slightly lower isolation rate. Enrichment time (24 or 48 h) did not affect the isolation frequency of campylobacters but longer enrichment time increased the growth of contaminants. Prefiltration through membranes of pore sizes 5.0 and 1.2 microns decreased the growth of contaminants. However, these membranes retain campylobacters and must be cultured to avoid underestimation. From more polluted waters campylobacters were isolated most frequently with CCD broth and CCDA medium.

Bacterial Typing Techniques↗

PubMed1987

Effects of different compositions of diets and chronic ethanol administration on proteolytic and antiproteolytic systems in the pancreatic tissue of rats.

The effects of dietary composition in combination with chronic ethanol ingestion on pancreatic proteolytic-antiproteolytic systems were studied by submitting 192 male Wistar rats to a 12-week dietary period. The rats were fed with a standard (S), fat-rich (F), protein-rich (P), or carbohydrate-rich (C) diet after randomized division into four groups. Half of the animals in each dietary group received water and the other half a mixture of 15% (v/v) ethanol and water as their drinking solution. The C-diet caused a significant increase of BAPNA hydrolysis, which was even more pronounced in rats receiving ethanol. Casein hydrolysis was increased significantly by the C-diet, but ethanol did not have any significant effect on this. Hydrolysis of ATEE was decreased significantly by the P- and C-diets, and ethanol in combination with the S- and F-diets decreased hydrolysis of ATEE in comparison with the corresponding water-receiving groups. The trypsin-inhibiting capacity of the pancreatic tissue was significantly increased in the group receiving C- and F-diets as compared to the S-diet-receiving group of animals. It seems that the composition of the consumed diet in combination with chronic ethanol ingestion may play a role in regulating the pancreatic proteolytic-antiproteolytic system. However, these changes were not parallel. The trypsin-inhibiting capacity of pancreatic tissue was also affected by the quality of the diet.

Alcoholism↗

PubMed1986

The effect of fat-rich, protein-rich, and carbohydrate-rich diets combined with long-term ethanol ingestion on the pancreatic proteolytic proenzymes in rats.

The effect of chronic alcohol ingestion on pancreatic adaptation to protein-, fat-, carbohydrate-rich and standard diets in rats was studied. Alcoholic animals received 15% (v/v) ethanol in their drinking water and controls tap water for 12 weeks. No mortality or dehydration was observed. After this diet period pancreases were removed, and specific and total activities of trypsinogen and chymotrypsinogen activities of the homogenates were determined. Ethanol itself did not have any significant effect on chymotrypsinogen or trypsinogen activities, but when combined with special diets significant increases were observed. The activity of chymotrypsinogen increased most in the alcohol and fat-rich diet group, that of trypsinogen in the alcohol and carbohydrate-rich diet group.

Alcohol Drinking↗

PubMed1985

A single-step solid phase radioimmunoassay for quantifying human carbonic anhydrase I and II in cerebrospinal fluid.

A single-step solid phase radioimmunoassay was developed to detect human carbonic anhydrase (CA) isoenzymes I (CA I) and II (CA II) in cerebrospinal fluid (CSF). The assay is capable of routinely detecting both isoenzymes at ng levels compared to the microgram levels of the traditional catalytic methods, which failed to demonstrate any CA activity in CSF. When the values of immunoreactive CA II in CSF were corrected for blood contamination (the CA I/CA II ratio of blood was about 7.9), the amount of brain tissue originated CA II could be calculated. The CA II values in CSF samples from 13 patients with multiple sclerosis were higher than those in CSF samples from 11 patients with various peripheral neurological disorders. Since CA II has been specifically localized to oligodendrocytes and myelin, our preliminary results suggest the possibility of CA II leakage from oligodendrocytes and myelin into CSF in demyelinating disease.

Carbonic Anhydrases↗

PubMed1983

Consequences of synovectomy of the knee joint: clinical, histopathological, and enzymatic changes and changes in 2 components of complement.

The state of 36 knee joints of 32 rheumatic patients was evaluated after surgical synovectomy, the follow-up period varying from 2 to 39 months. Synovitis was suspected by arthroscopy in 67% and verified histologically in 52%, although in a milder form than at the time of synovectomy. The regenerated synovial tissue was less permeable to serum proteins and contained lower activities of lysosomal enzymes than the excised synovial tissue. Although the number of leucocytes decreased in the joint fluid after synovectomy, the activities of lysosomal enzymes were lowered only slightly, and there was no change in the amount of C3 and C4 components of complement pathway.

Adult↗

PubMed1983

Immunolabeling of carbonic anhydrase isoenzyme C and glial fibrillary acidic protein in paraffin-embedded tissue sections of human brain and retina.

The specificities of carbonic anhydrase isoenzyme C (CA C) and glial fibrillary acidic (GFA) protein as immunocytochemical markers for different glial cell populations in human brain and retina were studied using indirect immunofluorescence and peroxidase-antiperoxidase complex methods. With antibodies against CA C, only those cerebral cells that were morphologically oligodendrocytes and Müller cells of the retina showed positive immunostaining reaction, whereas antibodies against GFA protein selectively labeled cerebral astrocytes and a part of the glial cells and fibers in the inner layers of the retina. In double labeling, when both glial cell markers were successively localized in the same cerebral tissue sections, GFA protein immunofluorescence was never found in the immunoperoxidase-stained CA C-positive cells, which further supports the oligodendrocyte-specificity of CA C in human brain.

Brain↗

PubMed1982

Carbonic anhydrase in the type I skeletal muscle fibers of the rat. An immunohistochemical study.

The localization of carbonic anhydrase (CA) was studied in rat skeletal muscles with the use of immunohistochemical (peroxidase-antiperoxidase) method. CA was observed in all those fibers that also showed pH 4.3 stable actomyosin adenosine triphosphatase activity (type I fibers), but the reverse did not necessarily hold. More specifically, CA was apparently localized in I-bands, and a weak reaction was also observed in sarcolemma. The function of CA in muscle fibers is possibly connected with the greater demands on CO2 transport and buffer system in muscles adapted to long-lasting contractions.

Adenosine Triphosphatases↗

PubMed1982

Immunohistochemical localization of carbonic anhydrase isoenzyme C in the central and peripheral nervous system of the mouse.

The regional and cellular distribution of the high activity carbonic anhydrase isoenzyme (CA C or CA II) in the mouse nervous system was investigated by an indirect immunoperoxidase (peroxidase-antiperoxidase) method using cross-reactive antibodies prepared against human CA C. In the mature brain an overall strong CA C specific reactivity was revealed in the heavily myelinated nerve tracts, the main immunostaining originating from small, intensively reacting cells interpreted as oligodendrocytes and from the myelin sheaths. An obvious straining was also revealed in the choroid plexus cells, especially in their free borders, and in the erythrocytes of the blood vessels, while the glial cells of the retina similarly exhibited a strong reaction. In the developing brain, CA C was absent shortly after birth, but achieved almost the mature pattern of distribution within about 3 weeks. In the spinal cord most of the positive cells were found in the grey matter, their processes projecting towards the white matter. No reaction was obtained in the sciatic nerve fibers or in the neuronal or satellite cells of the coeliac ganglion.

Aging↗

PubMed1981

Lysosomal hydrolases in different compartments of rheumatoid and osteoarthrotic joints.

Tissue samples from 226 rheumatoid and osteoarthrotic joints displayed increased activities of three lysosomal enzymes compared with controls. Variations in activity were evident--one tissue cannot be blamed for all joint destruction, no one enzyme can be used as a diagnostic tool. Free enzyme activities in synovial fluid reflected those in tissues, especially in cartilage and bone. Increased values in osteoarthrotic sera, close correlation of ESR to activities in joint compartments, and higher values in synovial fluid, cartilage and bone of seronegative rheumatoid patients were recorded.

Adult↗

PubMed1981

Proteolytic enzymes in joint destruction.

An increase in both neutral and acid proteolytic activity and proteinase inhibitors is reported in synovial fluid of osteoarthrotic and rheumatoid joints, compared with controls, but in subchondral bone and articular cartilage only Cathepsin D and in synovial tissue only neutral caseinolysis were elevated. Especially high proteolytic activities were found in joint compartments of seronegative rheumatoid and in sera of osteoarthrotic patients. The source of the main part of neutral caseinolytic activity in joint fluid is inflammatory cells, in the case of Cathepsin D the tissues of origin seem to be bone and cartilage.

Arthritis, Rheumatoid↗

PubMed1981

Histopathological findings in joint diseases. Comparison with enzymatic changes and clinical laboratory data.

The histopathological diagNoses of 155 rheumatoid and osteoarthrotic patients, when made without knowing the clinical data, were in agreement with that made by clinicians in 70% of cases. No single histological feature was pathognomonic for either disease, though synovial tissue was most important for the diagnosis. Some correlations between histopathological changes, enzymatic status of joint compartments and the clinical laboratory data were found, but only in the case of mild synovitis. In the more severe synovitis cases, and in diseased cartilage and bone of rheumatoid and osteoarthrotic joints, the enzymatic changes were not systematically related with particular histopathological features. The histology reflects the past, while the enzymatic status anticipates the forthcoming events.

Arthritis, Rheumatoid↗

PubMed1980

Purification of matrix-vesicle alkaline phosphatase from chicken epiphyseal cartilage and experiments on its ATP-hydrolyzing properties.

Matrix vesicles of epiphyseal growth cartilage are presumed to be the initial sites of mineralization. In order to discover whether matrix vesicle phosphatase could function as Ca2+-ATPase, we purified it from isolated matrix vesicles of chicken epiphyseal growth cartilage by n-butanol extraction, Sepharose 6B gel filtration, and DEAE-ion exchange chromatography. The enzyme protein hydrolyzes a number of phosphatase substrates, but showed one protein band when tested by polyacrylamide gel electrophoresis, and an antibody raised in a rabbit caused only one precipitation line in immunodiffusion and immunoelectrophoresis. The properties of the enzyme regarding the hydrolysis of ATP were studied at pH 7.6, which is close to the pH of the extracellular fluid of the cartilage. ATPase activity was stimulated by Mg2+ and Ca2+, but Ca2+ was a weaker activator and failed to stimulate the hydrolysis of ATP any further at the optimal Mg2+ concentration, indicating that the enzyme is not a "true" Ca2+-ATPase.

Adenosine Triphosphatases↗

PubMed1979

Matrix vesicles in chicken epiphyseal cartilage. Separation from lysosomes and the distribution of inorganic pyrophosphatase activity.

The extracellular matrix vesicles from epiphyseal cartilage of chickens were isolated by differential centrifugation. The matrix vesicles obtained showed considerable activity of lysosomal enzymes. This appears to have been due to lysosomal contamination because when we used a new density gradient medium (Percoll), the lysosomal enzyme activities and the activity of alkaline phosphatase could be totally separated. Electron microscopy of the alkaline phosphatase-rich fraction showed matrix vesicle-like structures. Phosphatase activities of the cells and matrix vesicles were further studied by Sephadex G-200 gel filtration. Specific magnesium-activated inorganic pyrophosphatase, distinct from nonspecific alkaline phosphatase, could be demonstrated in the cellular fraction. No such separate activity could be demonstrated in the matrix vesicle fraction, and it is supposed that the pyrophosphatase activity in the matrix vesicles originates from the alkaline phosphate.

Alkaline Phosphatase↗