Biomedical subjects

J Leinonen

Publications and source records attributed to J Leinonen.

42 records · Page 3Linked to original sources

PubMed1994

Time-resolved immunofluorometric assay of trypsin-2 complexed with alpha 1-antitrypsin in serum.

We developed a sensitive time-resolved immunofluorometric assay (IFMA) for trypsin-2 complexed with alpha 1-antitrypsin (AAT). We used a trypsin-2-specific monoclonal antibody on the solid phase and a europium-labeled polyclonal antibody to AAT as tracer. The detection limit is 0.05 microgram/L and the range of linearity extends to 100 micrograms/L. We compared the clinical utility of the trypsin-2-AAT assay with that of free trypsinogen-2 and amylase in serum by studying 120 healthy subjects, 29 patients with acute pancreatitis, 11 with extrahepatic biliary obstruction, and 34 with acute abdominal disorders of extrapancreatic origin. In patients with acute pancreatitis the median concentration of trypsin-2-AAT in serum was 59-fold that in healthy controls, 42-fold that in patients with biliary obstruction, and 33-fold that in patients with acute abdominal disorders of extrapancreatic origin. These differences are greater than those for trypsinogen-2 (19-, 20-, and 28-fold, respectively) and amylase (5.4-, 6.5-, and 5.4-fold, respectively). Compared with the assays of free trypsinogen-2 and amylase, our assay of trypsin-2-AAT improved the clinical specificity for acute pancreatitis by eliminating false-positive results in our control groups. Increased concentrations of trypsin-2-AAT and trypsinogen-2 were also observed in patients with chronic renal failure undergoing dialysis.

Abdomen↗

PubMed1993

Double-label time-resolved immunofluorometric assay of prostate-specific antigen and of its complex with alpha 1-antichymotrypsin.

We have developed a procedure for simultaneous immunofluorometric assay (IFMA) of prostate-specific antigen (PSA) and its complex with alpha 1-antichymotrypsin (ACT). A PSA-specific monoclonal antibody, which captures both free PSA and the PSA-ACT complex, was used as solid-phase antibody. Total PSA immunoreactivity was measured with a Eu(3+)-labeled PSA antibody that reacted with both free PSA and PSA-ACT. PSA-ACT was assayed simultaneously with a Sm(3+)-labeled polyclonal ACT antibody as a tracer. As standard we used pooled serum in which most of the PSA occurred as the PSA-ACT complex. The assay range was 0.03-500 micrograms/L for total PSA and 0.16-450 micrograms/L for PSA-ACT. In comparison with the assay for total PSA, assay of the PSA-ACT/PSA ratio improved the clinical specificity for cancer by reducing the number of false-positive results in prostatic hyperplasia.

Chromatography, Gel↗

PubMed1991

A complex between prostate-specific antigen and alpha 1-antichymotrypsin is the major form of prostate-specific antigen in serum of patients with prostatic cancer: assay of the complex improves clinical sensitivity for cancer.

We have studied the forms of prostate-specific antigen (PSA) in serum of patients with prostatic cancer and benign prostatic hyperplasia. Fractionation of serum by gel filtration and assay of the fractions for PSA showed that a considerable part of the PSA immunoreactivity in serum consisted of complexes that were larger than PSA. The complexes were assayed by time-resolved immunofluorometric assays based on an antibody against PSA on the solid phase and europium-labeled antibodies against various protease inhibitors as indicator antibodies. In addition to its monomeric form, PSA was found to occur in complex with alpha 1-antichymotrypsin. The proportion of the alpha 1-antichymotrypsin complex was a major form of PSA and it increased with increasing PSA concentrations, being over 85% at PSA levels exceeding 1000 micrograms/liter. A complex with alpha 1-protease inhibitor was also observed in serum of patients with prostatic cancer and very high levels of PSA. Complexes with alpha 2-macroglobulin and inter-alpha-trypsin inhibitor were detected, but their concentrations were low and similar in sera of cancer patients, normal men, and normal women, suggesting that they were not prostate derived. Commercial immunoradiometric assays for PSA were found to measure free PSA and its complexes with alpha 1-antichymotrypsin but not the complexes with alpha 2-macroglobulin and inter-alpha-trypsin inhibitor. The proportion of the PSA-alpha 1-antichymotrypsin complex was higher in patients with prostatic cancer than in those with benign hyperplasia. Therefore, assay of the complex had a higher sensitivity for cancer than assay of total PSA immunoreactivity.

Antigens, Neoplasm↗

PubMed1984

Management of chemical eye injuries with prolonged irrigation.

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.

Accidents, Occupational↗

PubMedDate not supplied

Salivary carbonic anhydrase isoenzyme VI is located in the human enamel pellicle.

Salivary carbonic anhydrase (CA VI) appears to protect teeth from caries via mechanisms other than direct regulation of salivary pH and buffering capacity. To elucidate whether CA VI acts in the local microenvironment of the tooth surface, we studied the location and activity of the enzyme in the human enamel pellicle. The study was performed using a specific rabbit antiserum to human CA VI in conjunction with immunostaining and immunoblot techniques. CA activity was demonstrated using a histochemical staining method. CA VI immunostaining of extracted teeth having in vivo formed pellicle showed that the enzyme is present in the enamel pellicle. Immunostaining for salivary alpha-amylase, which is known to be present in the pellicle, showed a similar staining pattern. The presence of CA VI in the enamel pellicle was confirmed by immunoblotting of in vivo formed pellicle proteins. In vitro studies showed that CA VI binds to polished enamel surfaces from both saliva and solutions of purified enzyme. The intensity of the CA VI immunostaining on the enamel surface was dependent on the concentration of the applied enzyme. The histochemical staining of in vitro formed enamel pellicle confirmed that the bound enzyme retains its enzymatic activity. The presence of active CA VI in the human enamel pellicle suggests that it may accelerate the removal of acid by functioning locally in the pellicle layer on dental surfaces.

Animals↗

PubMedDate not supplied

Reduced stability of prostate-specific antigen after long-term storage of serum at -20 degrees C.

The measurement of serum prostate-specific antigen (PSA) is widely used for the detection and management of patients with prostate cancer. Many studies on the validity of PSA as a marker for prostate cancer are performed on clinical samples that have been stored frozen for years. We have studied the stability of free (F), total (T) and complexed (C) PSA immunoreactivity and the proportion of free to total PSA (F/T) in serum after melting sera stored at -20 degrees C for 2 years and 2 weeks, respectively. In contrast to the decrease in PSA-F and F/T observed in fresh samples, PSA-C decreased and PSA-F increased in a time-dependent fashion after thawing samples that had been kept frozen for 2 years. This caused a net decrease in PSA-T and an increase in F/T. These results suggest that even though serum PSA is fairly stable during short-term storage, long-term storage at -20 degrees C reduces the stability of PSA immunoreactivity. Thus, results obtained on samples stored for prolonged times at -20 degrees C should be interpreted with caution. Because of the changes in PSA-F and F/T in both fresh and archival samples stored unfrozen, it is recommended that sera are melted only for the period required for pipetting the samples.

Biomarkers, Tumor↗