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Biomedical subjects

J Urban

Publications and source records attributed to J Urban.

At least 109 records · Page 6Linked to original sources
PubMed1989

Umbilical cord gamma-glutamyl transpeptidase and placental dysfunction.

Placental dysfunction has been suspected if human placental lactogen level and/or cystine-aminopeptidase activity were lower than 10th centile. Significant rise in gamma-glutamyl transpeptidase (GGTP) has been found in samples of arterial cord blood of newborns born to mothers with placental insufficiency. We observed the relationship between GGTP activity and decrease in cord pH and lower Apgar score of corresponding infants. We suggest that chronic hypoxemia as a consequence of placental dysfunction may result in damage of fetal liver cells.

Apgar Score↗
PubMed1989

Acid-base status of the newborn in relation to cord blood serum creatine kinase isoenzymes' activities.

Creatine kinase (CK) isoenzymes are considered to be specific tissue injury markers. The purpose of this study was to evaluate CK isoenzymes (CK-MM, CK-MB, and CK-BB) in umbilical cord blood sera of newborns in relation to their acid-base status. Investigations were performed in a group of 75 newborns delivered after 37 weeks of pregnancy. We estimated CK-isoenzymes with the use of DEAE-Sepharose C1-6B column chromatography. Total CK activity was measured using kits supplied by Boehringer-Mannheim (Monotest-R CK-NAC aktiviert). Newborns were considered hypoxic if umbilical artery blood pH was under 7.2 and/or base excess less than -10 mmol/L. Of 75 newly born infants 26 had features of perinatal hypoxia. We were unable to demonstrate significant differences in total CK, CK-MM and CK-MB activities in examined groups of newborns. We found a significant rise of CK-BB activity in cord sera of hypoxic infants. Our results show that the fetal brain is the most vulnerable to a hypoxic state.

Acid-Base Equilibrium↗
PubMed1987

Constitutive apical secretion of an 80-kD sulfated glycoprotein complex in the polarized epithelial Madin-Darby canine kidney cell line.

The biosynthesis, processing, and apical secretion of a group of polypeptides (Kondor-Koch, C., R. Bravo, S. D. Fuller, D. Cutler, and H. Garoff. 1985. Cell. 43:297-306) are studied in MDCK cells using a specific polyclonal antiserum. These polypeptides are synthesized as a precursor protein which has an apparent Mr of 65,000 in its high mannose form. This precursor is converted into a protein with an apparent Mr of 80,000 containing complex carbohydrates and sulfate. After intracellular cleavage of the 80-kD protein, the 35-45-kD subunits are secreted as an 80-kD glycoprotein complex (gp 80) linked together by disulfide bonds. Secretion of the protein complex occurs by a constitutive pathway at the apical surface of the epithelial monolayer. Since the immediate post-translational precursor, the 65-kD protein, is hydrophilic in nature as shown by its partitioning behavior in a phase-separated Triton X-114 solution, gp 80 is segregated into the apical exocytotic pathway as a soluble molecule. The proteolytic maturation of gp 80 is blocked in the presence of chloroquine and its secretion is retarded. The 80-kD precursor is released at the apical cell surface, demonstrating that proteolytic processing is not necessary for the apical secretion of this protein. If N-glycosylation is inhibited by tunicamycin treatment the protein is secreted in equal amounts at both cell surfaces, indicating a role of the carbohydrate moieties in the vectorial transport of this protein.

Animals↗
PubMed1986

Mechanical and biochemical properties of human articular cartilage in osteoarthritic femoral heads and in autopsy specimens.

We studied the mechanical and biochemical properties of articular cartilage from 22 osteoarthritic femoral heads obtained at operation and 97 femoral heads obtained at autopsy. Cartilage from the zenith and from the antero-inferior aspect of each head was tested both in tension and in compression. Water content, swelling ability and proteoglycan content were measured, the cartilage was examined histologically and the density of the underlying bone was assessed. Fifty-five of the autopsy specimens were defined as macroscopically normal because they exhibited no progressive fibrillation patterns on staining with Indian ink; but significant changes in water content, bone density and tensile strength related to age were seen in this group. In 20 pairs of femoral heads which were both macroscopically normal, we found, surprisingly, that cartilage from the left and right sides of the same patient was sometimes very different. Compared with the normal autopsy specimens the osteoarthritic specimens had a significantly increased swelling ability, a lower proteoglycan content and impaired mechanical properties, being both weaker in tension and softer in compression. Abnormal autopsy specimens had values intermediate between those of osteoarthritic and normal groups. Results from this abnormal group suggest that there is no primary loss of proteoglycan in early osteoarthritis.

Adolescent↗
PubMed1986

Mechanical and biochemical properties of human articular cartilage from the femoral head after subcapital fracture.

Articular cartilage from the femoral heads of 27 patients having an arthroplasty for subcapital fracture was studied, and its mechanical and chemical properties compared to those of a group of 33 age-matched macroscopically normal autopsy specimens. Water and proteoglycan contents were measured, as were swelling ability, compressive and tensile strength of the cartilage, and the density of the underlying bone. Cartilage from the fracture specimens had a significantly reduced proteoglycan content, as measured by fixed charge density, and increased swelling ability. These results indicate that this group differs from the "normal" population and care should be taken before they are accepted as control material for studies on osteoarthritic cartilage. Another finding was that bone density was much the same in the fracture and the normal group. This casts some doubt upon the concept that patients who sustain subcapital fractures are more osteoporotic than the average for the same age range.

Adolescent↗
PubMed1986

Concentration of free fatty acids (FFA) in amniotic fluid and maternal and cord serum in cases of intrauterine growth retardation.

There were no efficacious methods of diagnosing the syndrome of intrauterine growth retardation (IUGR) before birth. Only about 50% of cases with this syndrome can be recognized by clinical examinations. The aim of our investigations was an attempt to determine free fatty acid level (FFA) in amniotic fluid as a biochemical test in prenatal diagnosis. The investigations were carried out in 49 pregnant women and their newborns in whom IUGR was diagnosed clinically. The control group consisted of 30 pregnants who had an uneventful pregnancy and normal labor. Samples of amniotic fluid were taken in the first stage of parturition (dilatation of cervical os +/- 4-5 cm) by vaginal amniocentesis or amniotomy during cesarean section. The concentration of FFA in samples of amniotic fluid and serum were determined by Ducombe's method. It was found that during pregnancy complicated by IUGR, the free fatty acid concentration in amniotic fluid was almost three times higher than in normal pregnancy (0.355 mmol/l and 0.125 mmol/l) respectively. These differences are statistically significant (t = 12.58 p less than 0.001). Thus, determination of FFA can be used as a biochemical test in prenatal diagnosis of IUGR.

Amniotic Fluid↗
PubMed1985

Population trends and employment in the European CMEA countries.

The trends in population growth and employment in the European member countries of the Council for Mutual Economic Assistance (CMEA) as a whole were, in past decades, characterized by a relatively fast rate. At the same time, increases in the rate of employment exceeded in most of these countries, as a consequence of the activation of initial large reserves of the social labor force, increases in the population of reproductive age. In the 2nd 1/2 of the 1970s and in the early 1980s, the growth rate of labor resources was slower in most European CMEA countries due to demographic reasons. In view of the high rate of the economically active population, this was reflected in increased pressure for raising the productivity of labor. Some countries (Hungary, Poland) registered an absolute decrease in employment during that time.

Age Factors↗
PubMed1985

Influence of beta-receptor stimulation on catecholamine and phospholipid concentrations in lungs of fetal rabbits.

It was studied whether the beta-receptor stimulating fenoterol had any influence on endogenous catecholamines in the lung tissue of fetuses. On the 23rd, 27th and 31st days of pregnancy, concentrations of noradrenaline and dopamine in the lung homogenate of mature and immature rabbit fetuses were determined by fluorometry, and the basic surfactant components total phospholipids and lecithin by colorimetry, in a group receiving beta-mimetic treatment and in a control group receiving physiological salt solution. The concentration of noradrenaline decreased with the progression of pregnancy but the concentration of dopamine did not change significantly. Application of fenoterol caused an increase in total phospholipids and lecithin in the lungs of 23 and 27 day old rabbit fetuses and decreased the concentration of catecholamines, especially of noradrenaline. The drug had no such effect in mature (31 day) fetuses.

Animals↗
PubMed1984

Control of postcarotid endarterectomy hypotension with baroreceptor blockade.

The reported incidence of hypotension after carotid reconstruction ranges from 21 to 50 percent. To evaluate baroreceptor dysfunction, 283 carotid reconstructions were studied. During 181 consecutive reconstructions, a transcutaneous Teflon catheter was positioned intraoperatively at the carotid bifurcation for postoperative injection of lidocaine as necessary. Of 283 reconstructions, 210 (74 percent) were not followed by hypotension. In the remaining 73 (26.5 percent), hypotension (systolic blood pressure less than 100 mm Hg) was seen. In 14 of the 73 cases of hypotension, vasoactive drugs, atropine, or a fluid bolus was administered with variable responses. In 27 of the 73, no treatment was instituted. In the remaining cases of hypotension, treatment consisted of 1 to 2 ml of lidocaine administered through the catheter. A prompt increase in systolic blood pressure from 93 to 139 mm Hg (means) within 30 minutes of treatment occurred in 29 of the 32 cases (91 percent). These data currently support routine catheter placement.

Blood Pressure↗
PubMed1984

The measurement of mercury excretion in urine.

The determination of mercury in urine using cold atomic absorption spectrometry according to Gage and Warren is used after slight modification as standard method for the exposure test in persons exposed to its vapours in industry in Czechoslovakia. Within the concentration range between 100 and 600 nmol X l-1 of urine the relative standard deviation was lower than 4%. In workers exposed to mercury in the production of thermometers, fluctuation of urinary mercury concentration due to variations in diuresis could be greatly reduced by adjustment for endogenous creatinine. After the intake of 2.2 or 2.5 l of liquids the concentration of mercury in urine dropped considerably, but returned again to its initial value within 4 hours after fluid intake. The mercury half-life in the organism is estimated at about 30 days, but may be longer at mercury concentrations of 1 mumol X l-1. Contradictory to the original expectation, the Araki's coefficient b that is recommended for suppressing the effect of the volume of excreted urine on the concentration of urinary substances was found to be concentration-dependent: at 500 nmol X l-1 its value shifted towards 1 (0.85), at 100 nmol X l-1 towards zero (0.2-0.3). It is believed that mercury urinalysis data adjusted for endogenous creatinine are sufficiently reliable to be used for assessing the risk of human exposure to mercury.

Air Pollutants, Occupational↗