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Biomedical subjects

A Laine

Publications and source records attributed to A Laine.

At least 73 records · Page 4Linked to original sources
PubMed1987

Identification of proteins by crossed immunoelectrophoresis with a trap-gel.

Simple improvements of the crossed immunoelectrophoresis method are described. A trap-gel was prepared with a small quantity of monospecific antiserum and was submitted to preelectrophoresis. It blocked, during the first dimension, an individual protein as a rocket. The corresponding peak was reduced or disappeared in the second dimension. Identification of precipitation peaks in human or Macacus cynomolgus bronchoalveolar lavage fluids is illustrated and unequivocal recognition of some antigens is shown.

Animals↗
PubMed1987

"In vivo" and "in vitro" inhibition of human pancreatic chymotrypsin A by serum inhibitors.

The interaction of human pancreatic chymotrypsin A with serum inhibitors was assessed by enzyme immunoassay, enzymatic activity and inhibitory capacity measurements and electrophoretic analyses. In normal serum, chymotrypsin A was detected in four forms: one form (Mr approximately equal to 25,000) which might be chymotrypsinogen A and three forms complexed to the main inhibitors present in serum, alpha 2-macroglobulin (alpha 2-M), alpha 1-proteinase inhibitor (alpha 1-PI) and alpha 1-antichymotrypsin (alpha 1-Achy). As chymotrypsin A remains to 90% active when bound to alpha 2-M, the chymotrypsin A/alpha 2-M complex was quantified by an enzymatic assay. The kinetic parameters of the interaction of chymotrypsin A with alpha 1-PI and alpha 1-Achy were determined. Using these data the partition of chymotrypsin A between the different inhibitors in serum was calculated. In acute pancreatitis, the chymotrypsin A plasma level follows the progression of the disease and in this case as well as in normal serum alpha 1-PI is the major antagonist of chymotrypsin A.

Blood Proteins↗
PubMed1985

Human serum alpha 1-antichymotrypsin is an inhibitor of pancreatic elastases.

Incubation of human serum alpha 1-antichymotrypsin with human pancreatic elastase 2 or porcine pancreatic elastase results in the complete inhibition of each enzyme as determined by spectrophotometric assays. alpha 1-Antichymotrypsin reacts much more rapidly with the human than with the porcine enzyme. The inhibitor: enzyme molar ratio, required to obtain full inhibition of enzymatic activity, is equal to 1.25/1 when alpha 1-antichymotrypsin reacts with human pancreatic elastase 2 while it is markedly higher with porcine pancreatic elastase (5.5/1). Patterns obtained by SDS/polyacrylamide gel electrophoresis of the reaction products show the formation with both enzymes of an equimolar complex (Mr near 77 000) and the release of a fragment migrating as a peptide of Mr near 5000. Moreover a free proteolytically modified form of alpha 1-antichymotrypsin, electrophoretically identical with that obtained in the reaction with cathepsin G or bovine chymotrypsin, is produced in the reaction with each elastase but in a much greater amount when alpha 1-antichymotrypsin reacts with porcine elastase than with human elastase. As a consequence of our findings, the specificity of alpha 1-antichymotrypsin, so far limited to the inhibition of chymotrypsin-like enzymes from pancreas and leukocyte origin, has to be extended to the two pancreatic elastases investigated in this work. A contribution of alpha 1-antichymotrypsin to the regulatory balance between plasma inhibitors and human pancreatic elastase 2 in pancreatic diseases is suggested.

Animals↗
PubMed1985

Conversely exposure-related effects between atmospheric m-xylene concentrations and human body sense of balance.

Effects of fixed and fluctuating concentrations of m-xylene in air were studied on human psychophysiological functions. Nine healthy male volunteers were exposed to m-xylene 4 hrs a day, 3 hrs in the morning and 1 hr in the afternoon, with a 40 min. break in between. The subjects were sedentary or exercised at 100 W for 10 min at the beginning of each session in the chamber. The m-xylene concentrations in the air were fixed (8.2 mumol/l; 870 mg/m3) or fluctuated with peaks (5.2-16.4 mumol/l; 550-1740 mg/m3) but the TWA (8 hrs) concentration of m-xylene was always 4.1 mumol/l (435 mg/m3). The two control days, with and without exercise, were similar to the exposure days, but without exposure. Reaction times were measured with a device in which subjects responded to visual and auditory stimuli. Body sway was measured with the subjects' eyes open and closed with a strain gauge transducer platform. Changes in reaction times did not correlate with m-xylene concentrations in the air. Changes of average and maximal body sway were, however, consistently negatively correlated with the intensity of the atmospheric exposure to m-xylene at the beginning of each session in the chamber. Physical exercise combined with exposure to m-xylene improved rather than impaired body sway.

Adult↗
PubMed1985

Interaction of human alpha 1-proteinase inhibitor with human leukocyte cathepsin G.

Interaction of human plasma alpha 1-proteinase inhibitor (alpha 1-PI) with human leukocyte cathepsin G was assessed by proteinase inhibitory capacity assays and electrophoretic analyses. Only a part of purified alpha 1-PI formed a 1 : 1 complex (Mr = 74 000) with leukocyte cathepsin G. The formation of this complex was accompanied by the appearance of a great amount of a free, proteolytically modified form of alpha 1-PI (Mr = 50 000) which had lost its inhibitory capacity. The complex was unstable with time and the only dead end product observed was a modified, inactive form of alpha 1-PI. During the breakdown of the complex, no release of active enzyme could be measured by spectrophotometric assays. In spite of the fact that the equimolarity of the complex was convincingly demonstrated, studies of the alpha 1-PI-cathepsin G reaction showed that total inhibition of this proteinase needed a large molar excess of alpha 1-PI. Nevertheless, alpha 1-PI acts as an efficient "suicide inhibitor" since no cathepsin G recovery was ever found.

Cathepsin G↗
PubMed1984

Interaction of human alpha 1-antichymotrypsin with chymotrypsin.

Human alpha 1-antichymotrypsin reacts with bovine chymotrypsin to form an equimolar complex and this reaction is accompanied by the formation of a free, modified form of the inhibitor. Time-course studies, performed on mixtures containing an excess of native inhibitor and kept at 0 degree C or at 25 degrees C, show that the equimolar complex dissociates spontaneously; this dissociation results in the release of inactive modified alpha 1-antichymotrypsin and of some active enzyme, which is able to recycle with active inhibitor in excess. When all the native inhibitor is used up, the released active enzyme degrades the remaining intact complex into intermediate forms. At the endpoint of the reaction only inactive modified inhibitor and some active chymotrypsin remain. Immunochemical data indicate that, in the complex, a steric hindrance of the antigenic determinants of the inhibitor prevents the formation of the precipitate with specific antiserum. Inactive modified inhibitor, which has dissociated from the complex, has retained antigenic determinants of the native alpha 1-antichymotrypsin.

Animals↗
PubMed1984

Immediate effects of m-xylene on the human central nervous system.

Male volunteers were exposed to m-xylene vapour for 4 h a day either sedentary or with a period of 10 min exercise twice a day with stable (8.2 mumol/l) m-xylene concentrations or fluctuating concentrations with peaks (16.4 mumol/l). The TWA concentration was always the same (8.2 mumol/l). The body balance of the subjects was clearly impaired in the anteroposterior (a-p) direction, especially with their eyes closed during the peaks at rest, whereas it was improved when exercise was included in spite of the higher blood m-xylene concentrations. When on the contrary, the situation was reversed in the lateral direction. Complex audiomotor reactions were impaired after the peaks combined with exercise, whereas changes in simple reaction times were similar in pattern to those found for body balance in the a-p direction. The results suggest a complex interaction between physiological factors and m-xylene and development of adaptation or tolerance during the exposure.

Air Pollutants, Occupational↗
PubMed1984

Urinary disposition of ethylbenzene and m-xylene in man following separate and combined exposure.

Four volunteer subjects were exposed to 150ppm (655 mg/m3) of ethylbenzene and 150ppm (655 mg/m3) of m-xylene both separately and in combination. The biotransformation of the solvents was studied on the basis of the metabolites found in the urine. The metabolic conversion of both m-xylene and ethylbenzene proceeded mainly through oxidation of side chains. Ring oxidation seemed to be of minor importance; in the case of ethylbenzene it accounted for 4.0% (combined share of 4-ethylphenol, p- and m-hydroxyacetophenones) and in case of m-xylene for 2.5% (2,4-dimethylphenol), respectively. Mandelic and phenylglyoxylic acids amounted to 90% of the ethylbenzene metabolites, whereas m-xylene were excreted to 97% in the form of m-methylhippuric acid. Almost equimolar amounts in the form of metabolites of both solvents were found in the urine during 24h from the onset of exposure. Most of the ethylbenzene metabolites were excreted at substantially slower rates than those of m-xylene. The combined exposure resulted in a mutual inhibition of the metabolism of ethylbenzene and m-xylene, which was demonstrated by delayed excretion and decreased amounts of metabolites excreted. No sign of alteration in the urinary metabolite patterns of either ethylbenzene or m-xylene could be detected.

Adult↗
PubMed1983

Peripheral neuropathy and vibration syndrome. A clinical and neurophysiological study of 103 patients.

Hundred and three patients with suspected or diagnosed vibration syndrome caused by the prolonged use of chain saws were examined during 1978-1980. Neurological or neurophysiological examinations revealed slight changes suggesting polyneuropathy in the lower extremities of 42 patients. Peripheral neuropathy in the upper extremities was only detected in 39 patients. No evidence of peripheral neuropathy was found in 22 patients. The polyneuropathic patients did not significantly differ from the non-polyneuropathic patients with regard to other clinical symptoms and signs, laboratory findings, or data on exposure. We concluded that patients with neuropathic diathesis tend to be selected into groups of patients with suspected vibration syndrome. This study emphasizes the need for the careful neurological examination of each patient with suspected vibration syndrome.

Adult↗
PubMed1983

Studies on contact sensitivity to chromium in the guinea pig. The role of valence in the formation of the antigenic determinant.

Guinea pigs sensitized with either the trivalent chromium chloride or the hexavalent potassium dichromate are capable of reacting in vivo and in vitro to challenges with both chromium salts. This double reactivity is retained also after repeated restimulations with only 1 of these chromium compounds. From the failure to select lymphocytes directed specifically against a chromium determinant of a particular valence it is concluded that by sensitization with chromium salts of different valences a common determinant or closely related determinants are formed. It is suggested that this determinant is formed by chromium in the trivalent form.

Animals↗
PubMed1983

[Bronchoalveolar lavage in pneumoconiosis of coal miners. Biochemical aspects].

Broncho-alveolar lavage (LBA) was performed in 17 pneumoconiotics. The liquid obtained was analysed after gentle centrifugation to remove the cellular element, so that biochemical factors might be sought contribution to the evolution and progressive transformation to fibrosis. The percentage of liquid gathered was generally greater. Among the glycosidases found in all the 17 LBA analysed, the beta-D-glucuronidase, which was not detected in the LBA control subjects, was also found during the course of other pulmonary disorders. The elastolytic activity was characterized in 12 out of 17 LBA. In part it could originate from alveolar macrophages. An elevated number of macrophages (greater than 20 X 10(6) for the whole lavage) allied to the presence of elastolytic activity was found in 7 of 8 patients presenting with a pneumoconiosis and signs of progressive pulmonary disease. The collagenase and cathepsin B were present in the LBA of certain pneumoconiotics, but the significance of their presence is still unknown. The three major antiproteases of the serum exist in the LBA of pneumoconiosis. The quantity of alpha 1-antiprotease has identified a group of 6 patients whose LBA showed raised alpha 1-antiprotease, an elastolytic activity and for 5 of them progressive outcome.

Adult↗
PubMed1982

Uniformity of glycans within molecular variants of alpha-protease inhibitor with distinct affinity for concanavalin A.

Human alpha 1-protease inhibitor contains four asparagine-linked carbohydrate chains per molecule. Three types of carbohydrate chains were released from the polypeptide backbone by hydrazinolysis: (a) biantennary (80%), (b) biantennary with an intercalated N-acetylglucosamine residue (14%), and (c) triantennary (6%). Using concanavalin-A-affinity chromatography, native and S-carboxymethylated alpha 1--protease inhibitor were fractionated into three distinct molecular variants which were shown to contain only one type (a, b, or c, respectively) of glycan per molecule. This and previous observations on other serum glycoproteins support the proposal of uniformity of glycan type within individual molecular variants of glycoproteins.

Blood Proteins↗
PubMed1982

Short-term exposure of human subjects to m-xylene and 1,1,1-trichloroethane.

Inhalation exposure of male volunteers to m-xylene (8.2 mumol/l, 200 ppm) and 1,1,1-trichloroethane (TCE) (8.2 and 16.4 mumol/l, 200 and 400 ppm), as well as to a combination of TCE (16.4 mumol/l) and xylene (8.2 mumol/l), induced only slight changes in psychophysiological functions such as body sway and reaction time. Exposure to the 8.2 mumol/l concentration of xylene or TCE tended to improve the performances, whereas TCE exposure at 16.4 mumol/l alone or in combination with xylene tended to have an opposite effect. The results thus suggest a biphasic acute effect of TCE on the central nervous system (CNS) and reveal that xylene and TCE together exhibit neither kinetic interaction nor synergistic nor antagonistic acute effects on the CNS functions studied.

Adult↗
PubMed1982

Metabolic interaction between m-xylene and ethanol.

Ingestion of a moderate dose of ethanol (0.8 g/kg) by volunteers prior to 4-h inhalation exposure to m-xylene (6.0 or 11.5 mmol/m3) caused marked alterations in xylene kinetics. After ethanol intake the blood xylene level rose about 1.5-2.0-fold and urinary methylhippuric acid excretion declined by about 50% suggesting that ethanol decreased the metabolic clearance of xylene by about one half during xylene inhalation. This effect was noticeable up until a few hours after completed xylene exposure. Urinary excretion of 2,4-xylenol, the minor m-xylene metabolite, was generally not decreased by ethanol and sometimes the reverse seemed to be the case. The disturbance of xylene kinetics can be hypothesized to be caused mainly by ethanol-mediated inhibition of microsomal metabolism. When four volunteers who ingested ethanol prior to m-xylene inhalation at the higher concentration were monitored for blood acetaldehyde, transiently raised levels were found without notable effects on ethanol elimination. This observation may explain why some individuals experienced dizziness and nausea during the combined ethanol-xylene exposure.

Acetaldehyde↗