PubMed Health⌕ Search

Biomedical subjects

K Jobst

Publications and source records attributed to K Jobst.

At least 55 records · Page 3Linked to original sources
PubMed1984

Fluorescence polarization analysis of antigen determinant peptides of human fibrinogen.

Fluorescamine-labelled human fibrinogen was degraded with trypsin. Using fluorescence detection, the degradation products were fractionated by Sephadex G 50 gel filtration. Fragments of 3000-10 000 molecular weight were isolated for the fluorescence polarization studies. Specific antifibrinogen antibody increased the polarization of the isolated low molecular weight fragments. These results suggest that even the smallest proteolytic fragments of fibrinogen contain antigen determinant sequences. The fluorescence polarization method offers a sensitive and valuable approach for the analysis of the small antigenic peptides of human fibrinogen.

Epitopes↗
PubMed1983

Effect of Triton X-100 on the electrophoretic mobility of the creatine kinase isoenzymes of serum and tissues.

The distribution of creatine kinase isoenzymes was studied in homogenates of human skeletal muscle, myocardium and brain tissue, and in sera. For the study of the cytosolar isoenzymes (MM, MB, BB) the tissues were homogenized with a Ca++- and Mg++-containing buffer. The membrane-associated isoenzymes were solubilized with buffer containing 1% Triton X-100. The isoenzymes were separated on polyacrylamide gel slabs. After treatment with Triton X-100 a membrane-associated isoenzyme of high activity, corresponding in mobility to cytosolar MM, was identified in brain tissue. No similar fraction was demonstrable in muscle tissue. The difference in the results is attributed to differences in the sensitivity of the creatine kinase isoenzymes of muscle and brain tissues. The cytosolar MM fraction of human sera is of more anodal mobility than that of tissue homogenates, and in the MM region subfractions have been demonstrated in some cases. Triton X-100 did not affect the electrophoretic mobility of the creatine kinase isoenzymes of the sera, or of the tissue homogenates.

Cerebral Cortex↗
PubMed1982

Electrophoretic mobility of lymphocytes in neonates with cleft lip/palate and neural tube defect: a pilot study.

This study examined the surface charge of lymphocytes in newborns with fusion-type defects. Significant difference was found in the electrophoretic mobility of cells between normal controls (0.89 +/- 0.02) and neonates with cleft lip/palate (1.01 +/- 0.02; P less than 0.01) or neural tube defect (0.99 +/- 0.02; P less than 0.02). The cell frequency/mobility histograms revealed unimodal distribution for controls, but bimodal distribution for malformed infants of both types. It is suggested that alterations in the genetically determined cell surface charge properties might play an important role in fusion-type defects.

Cell Membrane↗
PubMed1981

Low-molecular-weight zinc-binding proteins in liver cytosol of the allylisopropylacetamide (AIA) treated rats.

Rats maintained on a normal diet supplemented with 10 microCi 65Zn/day for a period of 10 days were given allylisopropylacetamide (AIA), 400 mg/kg body weight: 24 h later they were killed. Cytosol was prepared from liver cells and analysed by gel filtration on a Sephadex G-75 column. The AIA treatment caused an alteration in the chromatographic pattern of Zn-binding proteins, and a low-molecular-weight fraction appeared.

Acetamides↗
PubMed1980

ADP induced surface charge changes of adult and newborn platelets.

In experiments reported here electrophoretic mobility of washed platelets and platelets suspended in diluted plasma obtained from adults and newborns was practically the same. No significant difference was observed in the pH-mobility relationship of the two types of platelets. These comparative studies indicate that the actual charge density, i.e. the number and sign of the charged groups at the newborn and adult platelet surfaces are essentially identical. However, a significant difference was found between the two platelet populations in the mobility changes induced by ADP. On the basis of cross over experiments between the platelets and plasma of adults and newborns it seems likely that the different behaviour of neonatal platelets arises from a difference between adult and newborn plasma. Preliminary results indicate that this may be due to the presence in adult plasma of a component with molecular weight about 10 000.

Adenosine Diphosphate↗
PubMed1980

On the mechanisms of renal sodium handling in newborn infants.

In an attempt to delineate the specific tubular defect in sodium reabsorption in low-birth-weight neonates, fractional sodium excretion (CNa/CCr), distal tubular sodium delivery (CNa+CH2O), and tubular sodium reabsorption [(CH2O/CH2O+CNa) X 100] were determined in 8 healthy premature and 10 full-term newborn infants. The mean birth weight was 1,701 g (range: 1,240--2,120 g) and the mean gestational age was 32.6 weeks (range: 28--35 weeks) for premature; and 3,199 g (range: 2,670--3,670 g) and 38.9 weeks (range: 38--41 weeks) for full-term neonates. It was demonstrated that the significantly higher fractional sodium excretion in premature infants (1.44 +/- 0.33 SE versus 0.36 +/- 0.09%), p less than 0.01) resulted from significantly decreased proximal (CNa+CH2O : 0.674 +/- 0.105 versus 0.360 +/- 0.069 ml/min/1.73m2, p less than 0.05) and distal [(CH2O/CH2O+CNa) X 100:69.9 +/- 3.3 versus 85.8 +/- 3.4%, p less than 0.01] tubular sodium reabsorption.

Blood↗
PubMed1980

Electrokinetic analysis of the fetal erythrocyte membrane after trypsin digestion.

Treatment of intact erythrocytes with trypsin (TRY) produced a significant difference (P less than 0.001) in electrophoretic mobility (EM) of fetal and adult cells. The greater net negative charge of the fetal red blood cells (RBC) at the "new-electrokinetic surface" generated by TRY was further analyzed with cell-electrophoretic measurements combined with various enzymatic and chemical reactions. Formaldehyde or diazonium reaction known to eliminate positive (NH2) groups increased the net negativity of the TRY-digested adult and fetal RBC in the same extent leaving the distance between the EM values unchanged. When the TRY digestion was followed by neuraminidase (NASE) reatment, the decrease in EM of both types of erythrocytes was of the same magnitude, and the distance between the EM values of the TRY-treated fetal and adult RBC remained unchanged, too. Phospholipase-C (PLC) digestion performed after TRY treatment did not cause any change in EM, Either in adult or in fetal RBC. The results show that the greater net negativity of the fetal RBC surface after TRY digestion can be attributed to neither less positive (NH2) groups, nor more sialic acid or phosphoric acid molecules existing at the new electrokinetic surface. It is suggested that the fetal RBC membrane may possess more acidic amino acid exposed to the outside, when TRY liberates sialoglycoprotein from the outer surface of the membrane.

Adult↗
PubMed1980

Metal content of rat liver cell organelles.

Zn2+, Fe2+, Cu2+, Ca2+, and Mg2+ were determined by means of atomic absorption techniques in tetramethylammonium hydroxide digests of cell organelles isolated from normal rat liver tissue. The metal content of the cell organelles was expressed with reference to their protein content. The results showed that digestion with tetramethy la ammonium hydroxide can be applied for the determination of metal to protein ratios in the cell organelles and that these ratios appear to be suitable for the characterization of cell organelles.

Animals↗
PubMed1980

Zn-binding protein profile of rat liver cytosol. Chromatographic and electrophoretic study.

65Zn2+ was given to rats per os and intraperitoneally for in vivo labelling of Zn2+-metalloproteins of cytosol. At the chromatographic analysis of the cytosol, two 65Zn2+-containing protein peaks were found in per os, while an additional low molecular weight third peak appeared in the intraperitoneal dosing samples. The chromatographic fractions were further separated by a non-denaturing gradient polyacrylamide electrophoresis technique. At the electrophoretic analysis of the chromatographic fractions the recovery of 65Zn2+ was the highest in samples taken from a second chromatographic peak (88%), which indicates the presence of proteins with exceptionally strong Zn2+-binding character in the 30-40 000 molecular weight fraction of the cytosol.

Animals↗
PubMed1980

Swelling of nuclei and decondensation of chromatin in a multinuclear model.

Rat liver nuclei were isolated in the presence of a nonionic detergent, and the soluble proteins were extracted from them using low-salt solution. The isolated nuclei were then embedded in a fibrin clot which was cut into 4 to 5 mm3 pieces and placed into an AMICON pressure cell in the presence and absence of the soluble nuclear proteins. When the soluble nuclear proteins were present and when their concentrations reached 40 mg/ml, the nuclei were significantly larger and their chromatin more decondensed than in the absence of added proteins. Our findings suggest that the soluble nuclear proteins play a role in the regulation of nuclear volume and the hydration of chromatin.

Animals↗
PubMed1979

Postnatal development of renal sodium handling in premature infants.

To estimate the contribution of the specific defect in proximal and distal tubular reabsorption of sodium to renal salt wasting, fractional sodium excretion, distal tubular sodium delivery, and distal tubular sodium reabsorption were determined in 11 healthy premature infants. The study was performed on the seventh day and at weekly intervals thereafter up to the sixth week of life. Sodium clearance and fractional sodium excretion decreased significantly with increasing postnatal age (P less than 0.001). There was no significant alteration in either osmolar or free-water clearances. Distal tubular sodium delivery steadily decreased from 4.96 +/- 0.66 (mean +/- SE) in the first week to 3.3 +/- 0.41 ml/minute/dl GFR in the sixth week of life (P less than 0.05). Distal tubular sodium reabsorption was 69.5 +/- 2.36% in the first week, then rose significantly to reach a value of 83.7 +/- 1.85% in the second week (P less than 0.001) and remained practically unchanged thereafter. It is suggested that the rapid improvement of distal tubular sodium reabsorption in premature infants might result from forced stimulation by the excessively activated renin-angiotensin-aldosterone system.

Age Factors↗