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Biomedical subjects

S Steffen

Publications and source records attributed to S Steffen.

10 recordsLinked to original sources
PubMed2001

Conventional carbon dioxide application does not reduce cerebral or myocardial damage in open heart surgery.

BACKGROUND: Open heart surgery is associated with a significant risk of cerebral and myocardial dysfunction, which is attributed in part to air embolism from incompletely deaired cardiac chambers. To evaluate the impact of carbon dioxide (CO2) insufflation to the thoracic cavity, a prospective randomized study was designed. METHODS: A total of 62 elective patients were randomly assigned to CO2 insufflation (group I, n = 31) or control (group II, n = 31). According to the Parsonnet risk score, 16 patients in group I (52%) and 10 patients in group II (32%) were categorized as being at either high risk or extremely high risk. RESULTS: In group II, perioperative mortality was 16.1% (5 patients); in group I, 1 patient died (ns). Creatine kinase MB isoenzyme, as a marker of myocardial damage, was more elevated in group I after surgery (38.0 +/- 4.1 vs 28.0 +/- 2.1, p = 0.02). Neurocognitive test scores did not reveal significant postoperative differences between groups. CONCLUSIONS: Although mortality was lower with CO2 insufflation, no benefit could be demonstrated for markers of cardiac ischemic damage or neurocognitive outcome in this high-risk population. As CO2 concentrations in the thoracic cavity did not necessarily reach anticipated levels, our method of application is in question.

Aged↗
PubMed2000

Induction of AIDS virus-specific CTL activity in fresh, unstimulated peripheral blood lymphocytes from rhesus macaques vaccinated with a DNA prime/modified vaccinia virus Ankara boost regimen.

The observed role of CTL in the containment of AIDS virus replication suggests that an effective HIV vaccine will be required to generate strong CTL responses. Because epitope-based vaccines offer several potential advantages for inducing strong, multispecific CTL responses, we tested the ability of an epitope-based DNA prime/modified vaccinia virus Ankara (MVA) boost vaccine to induce CTL responses against a single SIVgag CTL epitope. As assessed using both 51Cr release assays and tetramer staining of in vitro stimulated PBMC, DNA vaccinations administered to the skin with the gene gun induced and progressively increased p11C, C-->M (CTPYDINQM)-specific CD8+ T lymphocyte responses in six of six Mamu-A*01+ rhesus macaques. Tetramer staining of fresh, unstimulated PBMC from two of the DNA-vaccinated animals indicated that as much as 0.4% of all CD3+/CD8alpha+ T lymphocytes were specific for the SIVgag CTL epitope. Administration of MVA expressing the SIVgag CTL epitope further boosted these responses, such that 0.8-20.0% of CD3+/CD8alpha+ T lymphocytes in fresh, unstimulated PBMC were now Ag specific. Enzyme-linked immunospot assays confirmed this high frequency of Ag-specific cells, and intracellular IFN-gamma staining demonstrated that the majority of these cells produced IFN-gamma after peptide stimulation. Moreover, direct ex vivo SIV-specific cytotoxic activity could be detected in PBMC from five of the six DNA/MVA-vaccinated animals, indicating that this epitope-based DNA prime/MVA boost regimen represents a potent method for inducing high levels of functionally active, Ag-specific CD8+ T lymphocytes in non-human primates.

Adjuvants, Immunologic↗
PubMed1997

[Examination of the total protein concentration and gamma-glutamyltransferase (gamma-GT) in calves during the first 14 days of life and their significance for predictions of health status in the first two postnatal weeks].

The objective of the present paper was to examine the development of the total protein concentration in blood serum and the gamma-GT activity in 49 calves in relation to the health status during the first 14 days of life. For this purpose, blood samples were taken immediately after birth of the animals, after 6, 12, 18 and 24 hours and from then onwards once a day with the calves being subject to a thorough clinical examination each time. All calves received pooled colostrum. At the end of the experiment, the calves were subdivided into three groups on the basis of their health status, i.e. control calves, calves with a slight or moderately severe disease and calves suffering from a severe disease. In all three groups the total protein concentration increased significantly after the colostrum intake and decreased slowly from the 2nd day of life onwards. The gamma-GT activity as well increased significantly after the colostrum intake and decreased rapidly after 12th hour of life and progressively in the further course of the experiment. Both parameters varied considerably from one calf to the next and no statistically significant differences in these parameters between the three groups could be found. It can thus be deduced that the total protein concentration in blood serum and the gamma-GT activity do not allow any predictions about the development of the health status during the first 14 days of life to be made.

Aging↗
PubMed1996

[On calving in the pasture during the fall (veterinary expert)].

The objective of the following study was a veterinary expert opinion dealing with the evaluation of the pasturing of a cow and her calf during fall with special respect to animal welfare. The legal basis of this expert opinion was the Animal Welfare Act as amended on 1993. It is emphasized that there are no binding legal regulations as to the pasturing of livestock and that, especially because of the increasing public interest in animal welfare matters, the definition of minimal requirements would be desirable.

Animal Husbandry↗
PubMed1995

[The use of an externally derived fetal electrocardiogram in obstetrical diagnosis in cattle for the evaluation of fetal vitality].

In 33 pregnant cows a fetal electrocardiogram (ECG) using an external lead was recorded during second stage of labor. A curve of the fetal heart rate pattern was drawn which served to determine the following parameters: basal heart rate, and amplitude as well as frequency of heart rate oscillation. These parameters were compared with APGAR scoring, colostrum intake, blood gas analysis as to their value for evaluation of vitality. There was a statistically positive correlation between basal heart rate during birth and base deficit after birth. Basal heart rate was negatively correlated with plasma pH measured after fetal expulsion. Amplitude of heart rate oscillation was negatively correlated with pH in plasma and concentration of standard bicarbonate, and was positively correlated with carbon dioxide pressure and base deficit. Calves with acidosis at birth or decreased colostrum intake had statistically significantly higher amplitudes of oscillation than healthy control calves. Basal heart rate of the fetus when used as the only parameter might not be suitable in order to exactly evaluate fetal vitality. In contrast, amplitude of heart rate oscillation more reliably indicated a disturbance of fetal condition. Under practical conditions, the described procedure of measuring fetal ECG is suitable in order to detect a viable fetus.

Animals↗
PubMed1994

[Non-recognition of a second fetus in a recumbent cow during veterinary obstetrical assistance (expert opinion)].

The objective of the expert opinion presented in this paper is the missing of a second fetus after veterinary obstetrical assistance in a downer cow. The necessity of a thorough examination after obstetrical manipulation is stressed with special reference to problems occurring in recumbent cows. In addition, possible complications after inappropriate removal of retained placental fetal membranes are discussed.

Animals↗
PubMed1992

Microgravity effects on sea urchin fertilization and development.

Gravity has been a pervasive influence on all living systems and there is convincing evidence to suggest that it alters fertilization and embryogenesis in several developmental systems. Notwithstanding the global importance of gravity on development, it has only been recently possible to begin to design experiments which might directly investigate the specific effects of this vector. The goal of this research program is to explore and understand the effects of gravity on fertilization and early development using sea urchins as a model system. Sea urchin development has several advantages for this project including the feasibility of maintaining and manipulating these cells during spaceflight, the high percentage of normal fertilization and early development, and the abundant knowledge about molecular, biochemical, and cellular events during embryogenesis which permits detailed insights into the mechanism by which gravity might interfere with development. Furthermore, skeletal calcium is deposited into the embryonic spicules within a day of fertilization permitting studies of the effects of gravity on bone calcium deposition.

Animals↗