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Biomedical subjects

L K Korhonen

Publications and source records attributed to L K Korhonen.

At least 19 recordsLinked to original sources
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↗
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↗
PubMed1979

Repair of bone defects by bone inductive material.

Experimental fibular defects in 16 rats were filled with an acid decalcified homogenous bone matrix (bone inductive material). Autogenous bone grafts in corresponding defects in the other legs of the same rats served as controls. After 3 months, 11 of the 16 defects filled with bone inductive material healed with bony union, but only 4 of the 16 defects treated with autogenous bone grafts had healed. The results suggest that bone inductive material can repair bone defects are too large to be healed by autogenous bone grafts.

Animals↗
PubMed1979

The bone inductive capacity of various bone transplanting materials used for treatment of experimental bone defects.

The bone defect repairing capacities of autogenous cancellous bone (ACB), decalcified bone (DB), autodigested "low-antigenic" bone matrix (LBM) and preserved bone (PB) were tested in experimental defects in rabbit scapulae. The healing of the defects was most effective with ACB transplants as judged by roentgenologic and microscopic studies. The DB and LBM transplants caused states of healing comparable to each other, and the PB transplants showed the least satisfactory results in this experiment. The ACB, DB and LBM transplants caused bone induction, which resulted in the formation of new bone, subsequent resorption of the transplanted material and rapid reshaping of the callus. The PB transplants caused no bone induction; only some growth of callus on the edges of the defect was observed and pieces of the transplanted material were seen as late as 10 weeks after the operation as dead particles encapsulated by fibrous tissue. The infiltrations of inflammatory cells around the PB transplants indicated a considerable host versus graft reaction whereas this reaction was less with the other materials tested.

Animals↗
PubMed1978

Immunohistochemical demonstration of carbonic anhydrase.

Rabbits were immunized using human erythroxyte carbonic anhydrase B (HCA B) purified by the modified methods of Armstrong et al. (1966) and Bernstein and Schraer (1972). The globulin fraction was isolated by ammonium sulphate precipitation. The anti-HCA B globulin was specific, when judged using the double diffusion technique of Ouchterlony and immunoelectrophoresis. No cross reaction with human erythrocyte carbonic anhydrase C was found, but cross reactions with erythrocyte carbonic anhydrase from rat, mouse and guinea pig were observed. Flurorescein isothiocyanate conjugated goat anti-rabbit globulin was used for the localization of HCA B in tissue sections and erythrocytes on slides.

Animals↗
PubMed1978

Purification of human prostatic acid phosphatase by affinity chromatography and isoelectric focusing. Part I.

The main isoenzyme of human prostatic acid phosphatases was purified by affinity chromatography on L(+)-tartrate linked to agarose and by isoelectric focusing. The enzyme was a single protein when examined by polyacrylamide gel electrophoreses, either as a native protein or in the presence of sodium dodecyl sulfate. The analytical recovery of enzyme activity was 19%. The specific activity was 40 18 mumol/(min X mg) for hydrolysis of 5.5 mmol/liter p-nitrophenyl phosphate at pH 4.8 and 37 degrees C. The purification factor was as great as 1900. The molecular weight of the enzyme as measured by gel filtration was 109 000 and by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate 54 000, indicating that the enzyme had been isolated in the dimer form. By this method we have achieved the best purification of human prostatic acid phosphatase so far.

Acid Phosphatase↗
PubMed1977

Inorganic pyrophosphatase activity distinct from alkaline phosphatase in rat bone.

The existence of a specific inorganic pyrophosphatase (PPi ase), distinct from alkaline phosphatase in bone has been suggested but is often regarded as questionable. In the present investigation, several features of PPi ase activity have been demonstrated, which suggest that it represents an enzyme protein different from those splitting phosphomonoesters and ATP. PPi ase was largely destroyed during extraction with n-butanol, which facilitated the solubilization of alkaline phosphatase and ATP splitting enzymes and only partially destroyed acid phosphatase. Two major groups of phosphate esters and pyrophosphates splitting enzymes were separated by gel filtration from homogenates of rat bones. The first pool contained high ATP-ase and phosphomonoesterase activities, but only low activity against inorganic pyrophosphate (PPi) in the presence of MgCl2. The second pool was most active against PPi at pH 7.5 in the presence of excess MgCl2 and only slightly hydrolyzed phosphomonoesters or ATP. Immunodiffusion showed that these 2 pools contained 2 distinct proteins. It was concluded that there exists a specific inorganic pyrophosphatase distinct from phosphomonoesterases and ATP-ases in bone tissue.

Adenosine Triphosphate↗
PubMed1976

Kurloff cells. 1. Histochemical characteristics of the Kurloff bodies.

Kurloff cells, characterized by a large inclusion body in ill-defined lymphoreticular cells, were induced in male guinea pigs by oestrogen administration. The inclusion body material was characterized by way of light- and electron microscopy and histochemical staining reactions. Nucleo-protein were not detected, but certian tests for amino acids were observed and, at the peripheral parts of the inclusion bodies, phospholipid tests were positive. However, forced proteolysis of lipid extractions failed to abolish the reactions for detection of carbohydrate-rich compounds in the inclusion bodies thus confirming that their main characteristics were those of glycoproteins. Series of histochemical tests demonstrated the presence of periodate-reactive 1, 2-glycol groups and sulphate radicals. Periodate-reactive material and sulphomucins represented two separate substances, as demonstrated by extractions and combined staining tests. Some characteristics common with chondroitin sulphates were observed but, on the other hand, the observed differences suggested a different type of sulphation. The inclusion body failed to show any hydrolytic, dehydrogenase or oxidative enzyme activities, thus being metabolically inactive, although the cells showed certain enzyme activities in their cytoplasm and cell organelles.

Animals↗
PubMed1976

Kurloff cells. 2. Histochemical and morphological characteristics of the Kurloff cells.

Kurloff cells (KB cells) containing a glycoprotein inclusion body appear in femal guinea pigs and can be induced in males by oestrogen administration. These cells are found in bone marrow, thymus, and in the red pulp of the spleen, but not in the lymph nodes. Gradually growing inclusion bodies were observed in a series of cells in these organs. Morphological and histochemical features suggested an active synthesis of the inclusion body material: cisternae of the endoplasmic reticulum fused with the membrane surrounding the inclusion body and by way of electron histochemical methods periodate reactive material was demonstrated in the endoplasmic reticulum, in the Golgi cisternae, and in the inclusion body. Enzymatic activities were not observed in the inclusion body, but otherwise the KB cells showed enzymatic activities of oxidative and glycolytic pathways. Marker enzymes for the granulocytes series, the plasma cells, the mast cells, and the monocyte-reticulum cell group were negative in the KB cells and thus, classification of the KB cells into a particular cell type was not possible, although these cells obviously belong to the lymphoreticuar system. Phagocytosis was not observed, either. The possible role of the KB cells in the immune system are discussed.

Animals↗