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Biomedical subjects

U Jacob

Publications and source records attributed to U Jacob.

26 records · Page 2Linked to original sources
PubMed1994

[Structured documentation in gastroscopy: a method for improved quality assurance?].

To further improve quality assurance of gastrointestinal endoscopy, a computer assisted documentation system for gastroscopic data was assessed. In this context, for the structured written recording system, parameters "expenditure of time" and "acceptance by doctors" was evaluated. Contrary to free, unstructured data recording, the structured system employing predefined terms was able to promote doctors' acceptance of endoscopic terminology standards.

Attitude of Health Personnel↗
PubMed1992

Protein control of iron-sulfur cluster redox potentials.

The relationship between the three-dimensional structures of iron-sulfur proteins and the redox potentials of their iron-sulfur clusters is of fundamental importance. We report calculations of the redox potentials of the [Fe4S4(S-cys)4]-2/-3 couple in four crystallographically characterized proteins: Azotobacter vinelandii ferredoxin I, Peptococcus aerogenes ferredoxin, Bacillus thermoproteolyticus ferredoxin, and Chromatium vinosum high potential iron protein (HiPIP). Our calculations use the "protein dipoles Langevin dipoles" microscopic electrostatic model, which includes both protein and solvent water. The variations in calculated redox potentials are in excellent agreement with experimental data. In particular, our results confirm the important role of amide groups close to the cluster in separating the potential of C. vinosum HiPIP from those of the other three proteins. However, the potentials of these latter exhibit a substantial range despite extremely similar amide group environments of their clusters. Our results show that the potentials in these proteins are tuned in part by varying the access of solvent water to the neighborhood of the cluster. Our calculations provide the first successful quantitative modeling of the protein control of iron-sulfur cluster redox potentials.

Azotobacter vinelandii↗
PubMed1991

Clinical evaluation of decision support system for insulin-dose adjustment in IDDM.

OBJECTIVE: We developed a wallet-sized learning memory decision support system that helps patients with insulin-dependent diabetes mellitus adjust their insulin dosages. RESEARCH DESIGN AND METHODS: To determine the efficacy of the support system, we designed a randomized clinical trial with patients participating in a program in a diabetes education center. Patients were assigned to two groups of 21 patients each. All patients performed self-monitoring of blood glucose (SMBG) and were treated with multiple daily injections of insulin. Each of the patients was examined over a 32-day period. The basic educational program, i.e., practical advice in SMBG, diet, and exercise under homelike conditions, was identical in both groups. The only difference was that the first group used the computer for adjusting the insulin dose, whereas the second group received recommendations from the education team. RESULTS: The baseline HbA1 levels (9.8 +/- 1.6 vs. 9.9 +/- 1.6%) of both groups did not differ significantly. Mean blood glucose over the last 2 wk of the study was higher (P less than 0.01) in the second group (8.4 +/- 1.4 vs. 9.2 +/- 2.0 mM); the frequencies of hypoglycemic episodes were not different (1.7 vs. 2.3%). CONCLUSIONS: Metabolic control and safety were comparable in both groups. Thus, patients may benefit from such a system at home where no support by diabetes educators is available.

Adult↗
PubMed1991

[The surgical approach to the cochlear nucleus area].

The stimulation of the proximal auditory nerve or the Cochlear Nuclear Complex (CNC) situated in the lateral recess of the fourth ventricle is a possibility of hearing rehabilitation for patients suffering from bilateral deafness by bilateral cerebellopontine-angle tumors or by transsections of cochlear nerves on both sides. Using such anatomical landmarks as proximal cochlear nerve, flocculus, choroid plexus and taenia the surgeon can locate exactly the CNC for this stimulation. We investigated location, diameter and surrounding structures of the CNC on 10 human brains fixed in 10% formalin-solution and on 9 histological series of these subjects.

Acoustic Stimulation↗
PubMed1990

[Surgical anatomy of the petrous canal and posterior cranial fossa in relation to hearing preservation in surgery of acoustic neuroma].

The suboccipital (retrosigmoid) and the middle fossa routes are recommended for preservation of hearing in surgery for acoustic neuroma. We carried out a comparative study of the critical distances and bony landmarks on 520 petrous bones. Unlike the transtemporal route, the suboccipital approach offers no landmarks for identification of the common crus, the vestibule or the facial nerve; the lateral portion of the internal auditory canal is not always seen. The fundus can be seen in only 50% of bones without opening the labyrinth.

Adolescent↗
PubMedDate not supplied

Hashimoto thyroiditis is associated with defects of cytochrome-c oxidase in oxyphil Askanazy cells and with the common deletion (4,977) of mitochondrial DNA.

The activity of cytochrome-c oxidase, the terminal enzyme of the respiratory chain (complex IV), was studied at the ultrastructural level in a case of Hashimoto thyroiditis. Cytochrome-c oxidase showed a heterogeneous reaction pattern in oxyphil cells, with scattered foci of oxyphil cells lacking cytochrome-c oxidase staining. In most of the cells the defect involved all the mitochondria, but there were also oxyphil cells with a heterogeneous mitochondrial population characterized by an intracellular coexistence of mitochondria with either intact cytochrome-c oxidase or lacking activity. Immunocytochemistry further disclosed loss of mitochondrially and nuclearly encoded subunits of the enzyme. Molecular genetic analysis of mitochondrial DNA (mtDNA) revealed the presence of the 4977 base pair deletion ("common deletion") of mtDNA (8,482-13,459) in the affected areas but not in normal thyroid tissue of the patient. The amount of deleted mtDNA varied between 2 and 8% of total mtDNA. The results demonstrate that oxyphil cell change in Hashimoto thyroiditis is associated with functional and molecular genetic defects of the respiratory chain.

DNA, Mitochondrial↗
PubMedDate not supplied

Crystallographic analysis of phosphoglycerate kinase from the hyperthermophilic bacterium Thermotoga maritima.

Phosphoglycerate kinase from the hyperthermophilic bacterium Thermotoga maritima has been co-crystallized with its substrate 3-phosphoglycerate and the ATP analogue AMP-PNP using the vapour diffusion method. Crystals were obtained from a solution containing polyethylene glycol (MW 3000/8000) as precipitating agent. A complete diffraction data set from orthorhombic crystals was collected up to 2.0 A resolution. The TmPGK crystallizes in the space group P2(1)2(1)2 (cell dimensions: a = 62.0 A, b = 76.9 A, c = 87.5 A) with one molecule in the asymmetric unit. The structure was solved by Patterson search methods using Bacillus stearothermophilus PGK as a search model and was refined to a crystallographic R factor of 22.0%. Compared to the enzyme from B. stearothermophilus, horse, pig and yeast, the Thermotoga enzyme exhibits a drastically reduced interdomain angle, similar to the one reported for PGK from Trypanosoma brucei. Here we present crystallographic data of the first high-resolution structure of a PGK in largely closed conformation, complexed with the two products of the catalyzed reaction, and, at the same time, the first PGK structure from a hyperthermophilic organism.

Cloning, Molecular↗