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Biomedical subjects

J Krøll

Publications and source records attributed to J Krøll.

At least 19 recordsLinked to original sources
PubMed2002

Molecular chaperones and the process of cellular immortalization in vitro.

It is suggested that the chaperone-activity of the SV40 T protein is responsible for the first step in the process of cellular immortalization in vitro: the extension of life span of most transfected cells. Further that an additional up-regulation of selected molecular chaperones is causal in the second step of the process: the rare acquisition of an unlimited cell division potential. Possibly the molecular chaperones are evolution facilitators, enabling the immortalization of primary cells in vitro, as well as the evolution of longevity in species.

Animals↗
PubMed2001

Schizophrenia and liver dysfunction.

It is suggested that a non-hepatocellular liver dysfunction, caused by the presence of a congenital or acquired portal-systemic shunt, constitutes a major predisposing factor in the pathogenesis of schizophrenia. In addition to the common occurrence of schizophrenic reactions observed in liver disease, this suggestion is supported by autoptic findings in addition to the fact that a considerable number of abnormal biochemical and biological phenomena are shared by patients suffering from schizophrenia and portal-systemic shunting. The frequency of abnormal portal-systemic shunts in schizophrenia is unknown. Recent advances in non-invasive Doppler-sonographic techniques should enable an elucidation of this question.

Humans↗
PubMed2000

On the use of regression analysis for the estimation of human biological age.

The present investigation compares three linear regression procedures for the definition of human biological age (bioage). As a model system for bioage definition is used the variations with age of blood hemoglobin (B-hemoglobin) in males in the age range 50-95 years. The bioage measures compared are: 1: P-bioage; defined from regression of chronological age on B-hemoglobin results. 2: AC-bioage; obtained by indirect regression, using in reverse the equation describing the regression of B-hemoglobin on age in a reference population. 3: BC-bioage; defined by orthogonal regression on the reference regression line of B-hemoglobin on age. It is demonstrated that the P-bioage measure gives an overestimation of the bioage in the younger and an underestimation in the older individuals. This 'regression to the mean' is avoided using the indirect regression procedures. Here the relatively low SD of the BC-bioage measure results from the inclusion of individual chronological age in the orthogonal regression procedure. Observations on male blood donors illustrates the variation of the AC- and BC-bioage measures in the individual.

Aged↗
PubMed1998

On the use of patient data for the definition of reference intervals in clinical chemistry.

To improve the definition of reference intervals using patient data in clinical chemistry we studied the use of single results as a selection criterion (i.e. those results judged by the clinician not to require confirmation or which are considered unimportant for clinical screening purposes). Using this criterion 95% intervals were defined for S-albumin, S-cholesterol, S-creatinine, B-glucose, B-haemoglobin and S-urea similar to the corresponding reference intervals determined for healthy adults. Data collected from patients in the age interval 45-95 years demonstrated a significant decrease in levels of S-albumin and B-haemoglobin with age, an increase in S-creatinine, B-glucose and S-urea levels, and a biphasic variation in level of S-cholesterol. It is suggested that these changes are not caused by disease but result from the ageing process. The use of selected patient data for characterization of these changes enables a linear or polynomial description to be made for the age-related changes in the reference intervals.

Adolescent↗
PubMed1995

Evaluation of mass spectrometric techniques for characterization of engineered proteins.

Mass spectrometric characterization of engineered proteins has been examined using bovine recombinant Acyl-CoA-Binding Protein (rACBP), [15N]-labeled rACBP, and a number of sequence variants of ACBP produced by site-directed mutagenesis. The mass spectrometric techniques include ESIMS and MALDIMS for analysis of the intact protein. Peptide maps have been obtained either by direct analysis of enzymatically derived mixtures by PDMS, ESIMS, and MALDIMS or by off- and on-line HPLC-mass spectrometry. ESIMS was found to be most accurate for analysis of intact proteins. The best sequence coverage in mapping was obtained by LC-ESIMS and by direct mixture analysis by MALDIMS. The latter technique was favorable in terms of sensitivity and speed. A general strategy for mass spectrometric characterization of engineered proteins is suggested.

Amino Acid Sequence↗
PubMed1993

Immunoelectrophoretic characterization of insulin monomers and polymers.

Insulin monomers and polymers were analysed by quantitative immunoelectrophoretic procedures. The Zn-insulin hexamer dissociated reversibly by dialysis against the Zn-free electrophoresis buffer. The Zn-insulin polymers showed precipitin reactions of partial identity. Monomeric salt-free insulin migrated as soluble immune complexes in the antiserum gel. The insulin monomer did not absorb the precipitating antibodies against the Zn-insulin polymers. Thus the polymer structure creates antigenic epitopes absent from the insulin monomer. As insulin is probably released from the beta cells in the relatively stable form of Zn-insulin hexamers, selective monomer assays might underestimate the total content of immunoreactive insulin in the biological fluids. Electroimmunoassay of Zn-insulin immunoreactive antigens in human urine defines a normal reference range of 10-25 ng/ml.

Humans↗
PubMed1989

The subunit composition of factor XIII proteins in normal and factor XIII deficient plasma and serum analysed by line immunoelectrophoresis.

Line immunoelectrophoresis was used for the characterization of human coagulation factor XIII in normal and factor XIII-deficient plasma and serum. In normal plasma, two immunoreactive factor XIII proteins termed XIII-p (Mr 330,000 Da) and XIII-s (Mr 170,000 Da) were identified within the beta-globulin fraction. Their reactions with monospecific antisera against known factor XIII subunits, suggests that the factor XIII-p and -s proteins recognized represent the factor XIII a2b2 tetramer and -b2 dimer, respectively. The concentration of the XIII-p protein was, in normal plasma, approximately 6 mg/l, in plasma from a case of congenital factor XIII, approximately 1 mg/l and in normal serum approximately 3 mg/l. The concentration of the XIII-s protein (approximately 18 mg/l) was unaffected by the coagulation process and normal in plasma and serum from the case of congenital factor XIII deficiency. Thus, the present investigation indicates the presence of an excess of the anticatalytic, DNA-binding factor XIII carrier protein in normal as well as in factor XIII-deficient plasma and serum.

Factor XIII↗
PubMed1986

E. coli antibodies in schizophrenia.

The present investigation demonstrates relatively high antibody titres against an E. coli O-antigen in sera from somatically healthy male schizophrenic patients. This observation supports the suggestion that abnormal portasystemic collaterals are relevant to the manifestation of schizophrenia.

Adult↗
PubMed1984

Tumor-induced growth-inhibitory activity isolated from the Yoshida ascites fluid by extraction with methanol.

Growth-inhibitory activity was isolated from the Yoshida ascites fluid by sequential precipitation with polyethylene glycol, extraction with methanol, LH 20 Sephadex chromatography and preparative agarose gel electrophoresis. The cell non-specific activity was tumor-related as far as analogous fractions prepared from normal sera were inactive. Flow cytometric analysis indicates that the inhibition of cell growth was caused by blockage of the G1-S and possibly the G2-M phase transitions. The active component migrates electrophoretically associated to an unidentified alpha 1-antigen. In aqueous solution the molecular size of the inhibitor is ill defined, due to a tendency to autoaggregation and hydrophobic interaction with the chromatographic media. The molecular weight of the inhibitor as estimated by LH 20 Sephadex chromatography in methanol is approximately 350 daltons. This chromatographic fraction contains prostaglandin-E2 cross-reactive material in amounts suggesting the participation of a prostaglandin derivative in the observed growth-inhibitory activity.

Animals↗
PubMed1983

Immunological identity between bovine preparations of thiol:protein-disulphide oxidoreductase, glutathione-insulin transhydrogenase and protein-disulphide isomerase.

Five preparations of bovine thiol:protein-disulphide oxidoreductase/glutathione-insulin transhydrogenase (EC 1.8.4.2) and one preparation of bovine liver protein-disulphide isomerase (EC 5.3.4.1) from four different laboratories showed immunological identity in double immunodiffusion and rocket-line immunoelectrophoresis. Consequently, thiol:protein-disulphide oxidoreductase/glutathione-insulin transhydrogenase and protein-disulphide isomerase, formerly classified as two separate enzymes, should be considered as alternative activities of the same enzyme.

Animals↗
PubMed1979

Renin binding proteins in plasma. Binding of renin to some of the plasma protease inhibitors, to lipoproteins, and to a non-trypsin-binding unidentified plasma protein.

Renin is found in mouse plasma as high molecular weight forms, in addition to the fully active 40 000 dalton form. By using freshly 125 I-labelled 40 000 dalton pure submaxillary mouse renin, no binding to plasma proteins was demonstrable. However, unfolding and refolding of the labelled renin by guanidine facilitated binding to specific mouse and human plasma proteins. By using antibodies against individual human plasma proteins, the specific binding proteins were identified to be the plasma protease inhibitors: alpha2-macroglobulin, inter-alpha-trypsin inhibitor, alpha2-antithrombin. Binding was also demonstrated to alpha1- and beta1-lipoproteins, albumin and to a non trypsin binding unidentified plasma protein. No binding to 56 other tested proteins was demonstrable. It is concluded that the native 40 000 renin does not bind, but that a conformational change of the renin molecule most likely is necessary before binding occurs. It is discussed whether or not inactive or high molecular weight forms of renin in plasma are 40 000 renin bound to plasma protease inhibitors and lipoprotein.

Animals↗
PubMed1978

Is high-molecular-weight-renin binding of renin to the protease inhibitors and lipoproteins?

1. Two high-molecular-weight forms of renin (molecular weights 800 000 and 70 000) are present in mouse plasma. 2. The 800 000 form could be activated and converted into the fully active 40 000 form, by acid or limited proteolysis. The 70 000 form was activated without change in molecular weight. 3. In addition to its enzymic activity, renin was measured by a direct radioimmunoassay, which revealed that the current acid treatment of plasma did not activate all the renin present. 4. Renin is stored as fully active 40 000 renin, with a specific enzymic reactivity of 0.4 times 10(-3) GU ng(-1), in the submaxillary gland of mice. 5. Pure 125I-labelled 40 000 submaxillary renin did not bind to plasma proteins. However, by changing the tertiary structure of renin, it was bound to some of the plasma protease inhibitors; alpha2-macroglobulin, inter-alpha-trypsin inhibitor and alpha2-antithrombin. It was also bound to alpha1- and beta1-lipoprotein, albumin and an unidentified plasma protein. No binding was seen to more than 50 other studied plasma proteins.

Animals↗
PubMed1976

Immunoelectrophoretic quantitation of trace proteins.

A method is suggested for increasing the sensitivity of quantitative immunoelectrophoresis to a level comparable with radioimmunoassay. This is achieved by electrophoretic elution of antigen from 0.1-10 ml samples placed in glass reservoirs on the electrophoresis plate.

Animals↗