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Biomedical subjects

J Schulz

Publications and source records attributed to J Schulz.

At least 55 records · Page 3Linked to original sources
PubMed1997

[Sucking and drinking behavior as criteria of vitality in newborn calves].

Newborn dairy calves (n = 82) were investigated for relations between frequency and intensity of sucking movements at the one hand and course of parturition, values of a modified Apgar-Score, time between birth and first standing as well as parameters in the blood (lactate, glucose, immunoglobulins, pH, base excess, pCO2) and the incidence of newborn diseases at the other hand. In another group 101 dairy and 533 crossbred calves (dairy x beef) were compared with regard to the course of parturition, vitality, sucking behaviour and the ability to stand and drink without help 12 hours post natum. Sucking behaviour can be recommended as a criterion of vitality alone or as part of a modified Apgar-Score. A frequency of 80 and more intensive sucking movements/min sucking time and the ability to stand and drink without human help within 12 hours post natum are physiological. In milk x beef crossbred calves this ability can be impaired even in cases of normal birth.

Animals↗
PubMed1996

Cellular alterations in collembolan midgut cells as a marker of heavy metal exposure: ultrastructure and intracellular metal distribution.

The ultrastructure of the midgut epithelial cells of Tetrodontophora bielanensis (Collembola) fed either with lead-, cadmium- or zinc-enriched food or kept under control conditions was compared by transmission electron microscopy (TEM). Atomic absorption spectrophotometry (AAS) showed accumulation of these three metals in the body tissues of the collembolans. Intracellular localization of zinc in the midgut epithelial cells was investigated by electron spectroscopic imaging (ESI) and electron energy loss spectroscopy (EELS). The presence of lead in the midgut tissue was shown by laser microprobe mass spectrometry (LAMMS). Under heavy metal conditions, the midgut cells showed different ultrastructural alterations, the degree of which was found to be dose-dependent. Independent of the type of the metal in the food, the endoplasmic reticulum appeared fenestrated or vesiculated, and often large vacuoles, which were shown to be ER-derived, occurred throughout the cells. Also the mitochondrial membranes were affected by heavy metal stress. In epithelial cells of individuals exposed to either lead or cadmium, an increase of myelin-like structures could be observed. In the case of exposure to zinc in the highest applied concentration, the cytoplasm showed condensation and portions of the microvillous border appeared destroyed. Additionally, an increase of mineral congregations (type-A spherites) could be observed under heavy metal influence. Intracellularly stored zinc could be localised at highly affected mitochondrial membranes, in the microvillous border, and in the heterochromatin.

Animals↗
PubMed1996

(-)-Arctigenin as a lead structure for inhibitors of human immunodeficiency virus type-1 integrase.

The natural dibenzylbutyrolactone type lignanolide (-)-arctigenin (2), an inhibitor of human immunodeficiency virus type-1 (HIV-1) replication in infected human cell systems, was found to suppress the integration of proviral DNA into the cellular DNA genome. In the present study 2 was tested with purified HIV-1 integrase and found to be inactive in the cleavage (3'-processing) and integration (strand transfer) assays. However, the semisynthetic 3-O-demethylated congener 9 characterized by a catechol substructure exhibited remarkable activities in both assays. Structure-activity relationship studies with 30 natural (1-6), semisynthetic (7-21), and synthetic (37-43, 45, 46) lignans revealed that (1) the lactone moiety is crucial since compounds with a butane-1,4-diol or tetrahydrofuran substructure and also lignanamide analogues lacked activity and (2) the number and arrangement of phenolic hydroxyl groups is important for the activity of lignanolides. The congener with two catechol substructures (7) was found to be the most active compound in this study. 7 was also a potent inhibitor of the "disintegration" reaction which models the reversal of the strand transfer reaction. The inhibitory activity of 7 with the core enzyme fragment consisting of amino acids 50-212 suggests that the binding site of 7 resides in the catalytic domain.

4-Butyrolactone↗
PubMed1996

Gastroesophageal reflux in infants: evaluation of a new intraluminal impedance technique.

In this study, pH metry was simultaneously applied with a new technique, the intraluminal multiple electrical impedance (IMP) procedure, for measuring gastrointestinal motility for gastroesophageal reflux (GER) detection. Seventeen infants with clinical symptoms of GER disease such as recurrent apnea, aspiration pneumonia, wheezing, and failure to thrive were investigated during two feeding periods. A single catheter combining a pH electrode with seven electrodes for impedance measurements over a distance of 8.5 cm was used for the investigation. In all patients, 185 acid episodes were detected by pH metry. In 106 of these 185 acid episodes, a unique pattern in the IMP readings was noted, indicated by a retrograde esophageal volume flow. These episodes were regarded as acid GER episodes. Seventy-one of the 185 acid episodes occurred during the clearance process of a preceding acid GER characterized by typical IMP readings of an anterograde bolus transport. Eight of 185 acid episodes were missed in the IMP readings for technical reasons. The IMP pattern described as characteristic for a GER was observed in 490 other episodes not detected by pH metry. More than 75% of all GER detected by IMP reached the pharyngeal space; 73% of all GER occurred during feeding and the first 2 postprandial hours and 27% occurred during the remaining time until the next feeding. Even during the latter period, 34% of GER were detected by IMP only; they were missed by pH metry. Volume clearance indicated by IMP was always completed earlier than acidity clearance. The results show that IMP technique facilitates the detection of all GER, whereas pH metry is confined to the measurement of acid GER. Therefore, this technique might improve the evaluation of GER disease and detection of GER in conditions with gastric hypoacidity.

Electric Impedance↗
PubMed1996

Respiratory syncytial virus infection: its role in aeroallergen sensitization during the first two years of life.

Our aim was to study the influence of infection with the respiratory syncytial virus (RSV) in non-hospitalized infants on sensitization to aeroallergens and the early manifestation of atopy. Six hundred and nine infants from the prospective German Multicenter Cohort Study on Atopy were included, 38% of whom had an elevated atopic risk. RSV IgG and IgM antibodies were tested by ELISA with gradient purified RSV antigen. Specific IgE against mites, cat dandruff, birch and grass pollens and relevant nutritional antigens were tested with CAP-RAST-FEIA (Pharmacia, Sweden). Of the cord sera 99% were positive for RSV-IgG, 44.7% at one year and 64.2% (n = 265) at two years of age. The positivity rate after 12 months varied with the season of birth, the number of siblings and the degree of exposure to tobacco smoke; and correlated closely with attacks of wheezing during infancy. Twenty (2.8%) children were found to be sensitized against at least one aeroallergen at one year, and 28 (10.5%) at two years. By the first birthday, mite sensitization (n = 3) could only be seen in the RSV-infected children; grass pollen sensitization (n = 9) was associated with RSV seropositivity (logistic regression model including the confounders mentioned above: with RSV IgG < p = 0.048 > and IgM < p = 0.0006 >), as was birch sensitization (n = 5) with RSV IgM (p = 0.009). No such differences could be detected at two years. No correlation of RSV seropositivity to any allergic manifestation could be found. We conclude, that it is only in the first year of life, that RSV infection plays a significant role in promoting sensitization against aeroallergens, which do not at this time produce allergic symptoms.

Air Pollutants↗
PubMed1996

The value of nifedipine in the treatment of hypertension, coronary heart disease and myocardial infarction (post-infarction therapy).

Calcium antagonists are among the drugs most often prescribed in the treatment of cardiovascular diseases. Among the 2000 preparations most often prescribed in Germany in 1994, there were 48 calcium antagonists which presented a prescription rate of 1268 million defined daily doses. Calcium antagonists of the nifedipine type are by far the most often prescribed preparations of this group. They are targeted mainly against hypertension and coronary heart disease, with post-infarction angina pectoris also featuring among their indications. Recent publications have, in consideration of indications on possible risks associated with nifedipine medication, fanned discussions on the pros and cons of nifedipine medication and thus the value of calcium antagonists in treating hypertension and CHD as well as post-infarction patients. The purpose of this report is to analyze the current situation and to draw conclusions for the practical use of calcium antagonists.

Adult↗
PubMed1996

[Tissue regeneration processes in the bovine mammary gland].

Tissue regeneration within the udder after mastitis is part of the healing process and may lead to restoration of the affected quarter. These in most cases multiple processes differ considerably in shape and size according to the duration and the type of the disease. They are distinct from the more uniform regenerative processes within the lobuli of the gland during colostrogenesis of the dry period.

Animals↗
PubMed1995

Determinants of cord-blood IgE concentrations in 6401 German neonates.

For screening atopy risk in 6401 (84%) of all infants born during the year 1990 in six obstetric departments of five German cities, cord-blood IgE values were determined with CAP-RAST-FEIA. After cases with elevated IgA values had been excluded, 25% of the values were above the detection limit of 0.35 kU/l, and 8.5% were above 0.9 kU/l. Boys had significantly higher values than girls (P < 0.001). The distribution of values was significantly different for different nationalities of mothers (P < 0.001). The percentage of elevated values (> 0.9 kU/l) increased significantly with the number of close family members with atopic history (P < 0.001). Regarding the atopic history of the father, siblings, and mother separately, only the mother's history had a significant association with the cord-blood IgE class (P < 0.001). The IgE values of 81 twin pairs correlated significantly with a coefficient of r = 0.4909 (P < 0.001). The smoking history of the parents during pregnancy showed an association with cord-blood IgE values (P < 0.02). No significant association could be shown between cord-blood IgE distribution and other variables, i.e., gestational age, birth size, birth modus, Apgar score, cord-blood pH value, neonatal problems, parity, age of the mother, medication during pregnancy, educational level of mother or father, time of year, or obstetric department. It is hypothesized that, in addition to some postpartum contamination or placental transfer of maternal IgE, cord-blood IgE values are also determined by the fetal immunologic reaction to intrauterine exposure to allergens and trigger factors, and by genetic influences.

Adrenal Cortex Hormones↗
PubMed1995

Autosomal dominant familial spastic paraplegia: reduction of the FSP1 candidate region on chromosome 14q to 7 cM and locus heterogeneity.

Three large pedigrees of German descent with autosomal dominant "pure" familial spastic paraplegia (FSP) were characterized clinically and genetically. Haplotype and linkage analyses, with microsatellites covering the FSP region on chromosome 14q (locus FSP1), were performed. In pedigree W, we found a haplotype that cosegregates with the disease and observed three crossing-over events, reducing the FSP1 candidate region to 7 cM; in addition, the observation of apparent anticipation in this family suggests a trinucleotide repeat expansion as the mutation. In pedigrees D and S, the gene locus could be excluded from the whole FSP1 region, confirming the locus heterogeneity of autosomal dominant FSP.

Alleles↗
PubMed1994

The amido black assay: a simple and quantitative multipurpose test of adhesion, proliferation, and cytotoxicity in microplate cultures of keratinocytes (HaCaT) and other cell types growing adherently or in suspension.

A new multipurpose cell micro-assay has been developed, using the protein dye amido black 10B as an indicator of cell numbers in 96-well plates. The assay is reliable, rapidly performed and can be combined with morphological evaluation and photography of stained cells. It permits investigations of various cell types including the human keratinocyte line HaCaT and subclones, mouse 3T3 fibroblasts and myeloma cells X63-Ag8.653. Briefly, cells are fixed by formaldehyde or glutaraldehyde and, following aspiration of fixative and non-adherent cells, are stained by amido black at pH 3.5. The protein-bound dye is completely eluted by NaOH and is scanned in a microplate reader at 620 nm against 405 nm or 750 nm. Non-adherent and semi-adherent cells are assayed by centrifugation of plates before fixation. The assay revealed a good linear correlation between absorbance of amido black, cell count and DNA content within the range 1000-64,000 HaCaT cells/well. The slope of the regression line varied with different cell types. Experiments with HaCaT cells and its c-Ha-ras oncogene-transfected subclones demonstrated the suitability of the assay for optimizing culture conditions, dose-response studies and for the screening and quantification of cell adhesion to extracellular matrix molecules. The assay was also used to evaluate cytotoxicity of drugs such as hexadecylphosphocholine, target cell killing in co-cultures with interleukin-2-activated lymphocytes, and the testing of hybridoma antibodies for their biological effects on proliferation and adhesion. The assay is highly reproducible, sensitive, independent of cellular aggregation and economic for multiple applications.

3T3 Cells↗
PubMed1994

Inhalation risk in low-gravity spacecraft.

Inhalation risks on long-duration manned spaced flight include gasses chronically released by outgassing of materials, gasses released during spills, thermodegradation events (including fires) with their attendant particulates, and fire extinguishment. As an example, an event in which electronic insulation consisting of polytetrafluoroethylene undergoes thermodegradation on the Space Station Freedom was modeled experimentally and theoretically from the initial chemistry and convective transport through pulmonary deposition in humans. The low-gravity environment was found to impact various stages of event simulation. Critical unknowns were identified, and these include the extent of production of ultrafine particles and polymeric products at the source in low gravity, the transport of ultrafine particles in the spacecraft air quality control system, and the biological response of the lung, including alveolar macrophages, to this inhalation risk in low gravity.

Aerosols↗
PubMed1994

[Somatic cells in goat milk].

In goats the somatic cell content (SCC) of raw milk is in general considerably higher (often several millions/ml milk) than in cow milk. This refers to milk from healthy and from mastitic mammary glands, to samples from infected and from non-infected udder halves and to single gland and to bulk milk samples as well. On the other hand, there is in every herd of dairy goats a considerable proportion of milk samples with low SCC, which fulfill in this respect all exigencies of a good milk quality. Part of this discrepancy is caused by the method that is used to determine the SCC (presence of nonleukocytic cell-like fragments in goat milk). Further research in order to explain the physiological and pathogenetic causes of the differences between SCC of goat and cow milk is needed before SCC standards and regulations for goat milk quality can be introduced finally.

Animals↗
PubMed1994

[Dermonecrosis along the course of the caudal branch of the lateral saphenous vein in foals due to a Staphylococcus aureus infection].

Necrosis of the skin on both lateral aspects of the hind limbs following the caudal branch of the lateral saphenous vein in 22 suckling foals is described. The first clinical signs were observed on days 2-5 post natum. S. aureus was isolated from the wounds. Decubitus in the region of the malleolus lateralis tibiae was considered the starting point of an ascending infection. This type of dermonecrosis was only observed in boxes with hard floors where the straw bedding was pushed aside by the lying foals regularly, never, however, in boxes with deep and permanent sawdust or straw bedding. Therapeutic and preventive measures are discussed.

Animals↗
PubMed1993

Atopic family history. Validation of instruments in a multicenter cohort study.

In order to identify newborns at risk for atopic diseases, we developed a family questionnaire and selected specific answers which were suitable to identify atopic family members. The validity of the questionnaire was evaluated by the Phadiatop test results of 793 mothers and 353 fathers. As both screening instruments do not measure the same, the Phadiatop test identifies sensitization to inhalant allergens and the history reflects the clinical manifestation of atopic disease, the agreement between sensitization and manifestation is incomplete. Sensitivity and specificity of the questionnaire screening conditions to reproduce the Phadiotop test result was 64% and 84% for mothers, and 58% and 88% for fathers, respectively. The relative risk for lifetime prevalence of atopic manifestations in Phadiatop positive over negative mothers was calculated to be 3.88 (95% confidence interval = 3.12 to 4.81), and for Phadiatop positive over negative fathers to amount 4.84 (95% confidence interval 3.25 to 7.23). A few relevant answers of 20 were identified by logistic regression analysis to predict the Phadiatop test result nearly, as well as the total questionnaire.

Adult↗
PubMed1993

[The wet weight and the content of DNA, RNA and protein of different tissues of 92 and 120 day old sheep fetuses and newborn lambs].

In sheep-fetuses of the age of 92 (615 +/- 49 g body weight) and of 120 days (1843 +/- 406 g body weight) as well as in newborn lambs (2815 +/- 648 g body weight) the content of DNA, RNA and protein per g wet weight in 14 tissues and in the fetal and the maternal portion of the placenta was analysed. A calculation of the development of the total content of DNA, RNA and protein in the different organs is given. The changes of the wet-weight:DNA-, the protein:DNA- and the RNA:DNA-ratio in the tissues during growth are described. The significance of these changes is discussed.

Animals↗