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Biomedical subjects

M Zacher

Publications and source records attributed to M Zacher.

5 recordsLinked to original sources

New concept for the development of a confocal endomicroscope.

It is one of modern medicine's top priorities to reduce the stress for the patient during diagnosis and therapy by designing minimally invasive applications of medical techniques. Microsystems technology has always held the key to minimally invasive solutions in surgery and micro-endoscopy. The new measuring system KOMED is currently developed for the application of in-vivo cellular microscopy. This approach is based on the concept of a miniaturised fibre-optical confocal microscope. The application range of this microsensor system includes the minimally invasive optical biopsy for purposes such as the early detection of tumour cells. In this paper the concept of the KOMED system is described, as well as technical challenges to be solved in the project.

Biopsy↗

Aortic root replacement versus aortic valve replacement: a case-match study.

BACKGROUND: There is increasing evidence that patients with aortic valve disease and dilatation of the ascending aorta are at risk for later dissection or rupture of the aortic wall when the dilated ascending aorta is not replaced or reinforced at the time of aortic valve replacement. In order to find out whether the more complex surgical procedure of aortic root replacement carries a higher early or late postoperative risk than isolated aortic valve replacement, we conducted a matched-pair study with patients of both groups. METHODS: Between June 1993 and August 1998, 100 consecutive patients with aortic valve disease and ectasia/aneurysm of the ascending aorta underwent replacement of the aortic valve and the ascending aorta with a CarboSeal composite graft (CarboSeal; Sulzer Carbo-Medics Inc, Austin, TX). Identical bileaflet valve prostheses (CarboMedics; Sulzer CarboMedics Inc, Austin, TX) were implanted during the same time period in 928 patients for aortic valve disease. On the basis of various preoperative clinical variables 100 patients with aortic valve replacement were matched to the 100 patients with replacement of the aortic root. The duration of follow-up for both groups was similar with 37 + 17 months (range, 9 to 70) for the CarboSeal group and 38 + 14 months (range, 13 to 65) for the CarboMedics group. Survival and morbidity were calculated by Kaplan-Meier analysis and risk-adjusted mortality was evaluated by multivariate analysis in a Cox regression model. RESULTS: The early postoperative mortality of 1% in the CarboSeal group and 4% in the CarboMedics group was insignificantly different. Although the overall survival rate at 5 years was lower (60.7% vs 86.3%; p = 0.13) in the CarboSeal group, the freedom from cardiac mortality and valve-related morbidity was similar in the two groups. CONCLUSIONS: Replacement of the ascending aorta and aortic valve can be performed with similar operative risk, valve-related morbidity, and late cardiac mortality as isolated aortic valve replacement.

Adult↗

Further observations on the doubling time of human chorionic gonadotropin in early asymptomatic pregnancies.

The doubling time (DT) of human chorionic gonadotropin (hCG) in serum was investigated retrospectively using serial serum hCG values that had been obtained from asymptomatic pregnant women with a prior history of infertility. The DT of hCG did not increase significantly as pregnancy advanced during the period in gestation when the serum hCG concentration was less than 10,000 mIU/mL (International Reference Preparation). Serum hCG concentrations increased subnormally in 2 of 60 women with normal intrauterine pregnancies, 5 of 8 women with asymptomatic ectopic pregnancies (EPs), and in 2 of 8 asymptomatic women who subsequently aborted their pregnancies. Neither the sensitivity nor the specificity of serial hCG testing for EP was enhanced by adopting different test criteria at different serum hCG concentrations.

Chorionic Gonadotropin↗

Stabilisation of human interferon beta synthesis in Escherichia coli by zinc ions.

Human interferon beta synthesized in Escherichia coli is unstable and toxic for the bacterial cell. Zinc ions are able to stabilise interferon beta in E. coli probably by inhibiting the action of cell internal proteinase(s) which affect the half-life of this foreign protein. As a result up to one order of magnitude more active IFN-beta can be detected in Zn2+-treated E. coli cells.

Cloning, Molecular↗