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Biomedical subjects

A Petzold

Publications and source records attributed to A Petzold.

49 records · Page 3Linked to original sources
PubMed1999

Central pain after pontine infarction is associated with changes in opioid receptor binding: a PET study with 11C-diprenorphine.

Using 18F-fluorodeoxyglucose and 11C-diprenorphine positron emission tomography (PET), we investigated alterations in glucose metabolism and opioid receptor binding in a patient with central poststroke pain, which developed after a small pontine hemorrhagic infarction. In comparison with normal databases, reduced 11C-diprenorphine binding was more accentuated than the hypometabolism on the lateral cortical surface contralateral to the symptoms, and a differential abnormal distribution between the tracers was seen in pain-related central structures. These results show that 11C-diprenorphine PET provides unique information for the understanding of central poststroke pain.

Adult↗
PubMed1998

Hue memory and discrimination in young children.

As first remarked by Charles Darwin (1877), very young children frequently have difficulty when naming or choosing colors. To investigate the cause of this difficulty, we have tested preschoolers (mean age = 4.1) for hue discrimination and hue memory and compared their results with those of preadolescents (mean age = 9.6) and young adults (mean age = 25.8). The tests were designed to minimize the influence of verbal coding on the results. We find that preschoolers are as good as the two older groups in hue discrimination. However, in visual hue memory, they are significantly poorer. The 3-fold increased errors they make, relative to preadolescents and young adults, may be related to the development of visual hue categories and the integration of verbal and visual processes. However, such errors cannot explain why young children often experience extreme difficulty in color naming.

Adolescent↗
PubMed1997

[Amebic colitis and amebic liver abscess--epidemiology and personal case report].

The large intestine reacts relatively monomorphically to different stimuli. From this differential-diagnostic problems may result. The history of a patient is described which could be pursued clinically over 12 weeks and during the course of which the correction of the diagnosis ulcerative colitis into amoebic colitis was necessary. It is concluded that in every symptomatology of colitis bacterial and parasitologic examinations of the faeces should be performed primarily specially if there is a history of overseas travel. In these cases it must be also thought of spontaneous amoebic infections.

Abdomen, Acute↗
PubMed1995

Rabbit liver cytochrome P-450 2B5: high-level expression of the full-length protein in Escherichia coli, purification, and catalytic activity.

Rabbit liver cytochrome P-450 2B5 (P-450 2B5) was expressed in Escherichia coli using the D(+)-galactose-inducible expression vector pJL-2, containing the full-length cDNA encoding P-450 2B5. Stimulation by galactose of protein synthesis in the presence of the heme precursor 5-aminolevulinic acid peaked 72 h after addition to the inducer to yield 108 nmol membrane-bound P-450 2B5 per liter of culture medium. The recombinant enzyme was purified to near homogeneity by a two-column procedure involving chromatography on DE-52 cellulose and hydroxylapatite. The hemoprotein was isolated mainly in the low-spin iron configuration and exhibited a reduced CO-difference spectrum with a Soret band at 451 nm. Second-derivative spectral analysis in the middle-UV region revealed that type I binding of 4-nitroanisole to ferric P-450 2B5 abolished absorption bands ascribable to tyrosine residues within the polypeptide chain. Pseudo-first-order rates of NADPH-driven reduction of the pigment were lower when reconstituted with NADPH-cytochrome P-450 reductase than with the mitochondrial adrenodoxin/NADPH-adrenodoxin reductase redox couple. The enzyme was catalytically active toward 4-nitroanisole and androstenedione; metabolic rates were enhanced to different extents by the presence of cytochrome b5. The recombinant hemoprotein did not catalyze bioactivation of 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone, a potent pulmonary carcinogen. The methods described here should facilitate further studies on the biophysical basis of the complex interactions of P-450 2B5 with its redox partners.

Amino Acid Sequence↗
PubMed1994

Identification of MYO4, a second class V myosin gene in yeast.

We have isolated a fourth myosin gene (MYO4) in yeast (Saccharomyces cerevisiae). MYO4 encodes a approximately 170 kDa (1471 amino acid) class V myosin, using the classification devised by Cheney et al. (1993a; Cell Motil. Cytoskel. 24, 215-223); the motor domain is followed by a neck region containing six putative calmodulin-binding sites and a tail with a short potential 'coiled-coil' domain. A comparison with other myosins in GenBank reveals that Myo4 protein is most closely related to the yeast Myo2 protein, another class V myosin. Deletion of MYO4 produces no detectable phenotype, either alone or in conjunction with mutations in myo2 or other myosin genes, the actin gene, or secretory genes. However, overexpression of MYO4 or MYO2 results in several morphological abnormalities, including the formation of short strings of unseparated cells in diploid strains, or clusters of cells in haploid strains. Alterations of MYO4 or MYO2 indicate that neither the motor domains nor tails of these myosins are required to confer the overexpression phenotype, whereas the neck region may be required. Although this phenotype is similar to that seen upon MYO1 deletion, we provide evidence that the overexpression of Myo4p or Myo2p is not simply interfering with Myo1p function.

Amino Acid Sequence↗
PubMed1991

[Effect of gastrointestinal hormones on duodenal motility in acute experiments].

In this study was observed the influence of Pancreozymin, Secretin, Glucagon, Pentagastrin and Somatostatin on the motility of duodenum in 256 seances in acute experiments on 12 dogs before and after truncal vagotomy and on 20 Wistar rats. As a control we used the return of the parameters of electrical and motor activity to their original levels. The reaction was registered with the help of electromyography, using bipolar electrodes and with measurement of intraluminal pressure, using open-tip catheter technique. Spike-activity was graphically presented and statistically performed. It was shown, that Secretin and Glucagon caused relaxation of duodenum, but Pentagastrin, Pancreozymin and Somatostatin stimulated duodenal motility with spastic component and gradual phasic character of a process. After truncular vagotomy the reaction to Pancreozymin and Pentagastrin was slowly, to Glucagon strongly reduced, but the reaction to Secretin was extended. We observed after TV either no reaction or a diminished reaction to Somatostatin. This study serves as experimental basis for use of gastrointestinal hormones and electromyography for diagnosis and therapy of motility disorders of duodenum in surgical practice.

Animals↗
PubMed1991

[Effects of pentagastrin and somatostatin on duodenal motility in chronic experiments].

Electromyography of the duodenums was performed in dogs, using two bipolar electrodes placed 5 and 10 cm aborally of the pylorus on the serosa of the duodenums. 10 days after implantation and 24 hours after the last meal the duodenal motility was registered in 9 bastard dogs for 5 hours. Pentagastrin, given as a 1-hour intravenous infusion, changed the interdigestive motility to an irregular (postprandial) pattern, which continued up to the end of measurement or was followed by a prolonged phase III with return to cyclic activity. Infusion of somatostatin for 1 hour interrupted the interdigestive motility leading to a prolonged phase I pattern and to partial discoordination. After the end of infusion phase III motility returning to cyclic activity or irregular activity were registered. A standard relaparotomy 10 days after implantation was performed in 3 dogs. Up to the second day of the postoperative period interdigestive cycles of duodenal motility were not obtained.

Animals↗
PubMed1990

[Electromyographic and manometric studies of the antrum and duodenal motility in rabbits under the influence of pentagastrin in a mechanical duodenal passage disorder].

The influence of a mechanical disturbance of the duodenum on the motility of the antrum and duodenum was investigated by means of the electromyography and the perfusion manometry. Thereby the effect of the pentagastrin stimulating the motility of the unstriated muscles of the gastro-intestinal tract was used for testing the function reserve of the antrum- and duodenal-muscles. After one and a half month of establishing the passage obstacle there occurs a complex disturbance of the electrical activity; the unstriated muscles does not react on a stimulating excitation.

Animals↗
PubMed1989

[Comparative animal experiments of bile duct anastomoses using microsurgical technics].

The purpose of the study was to optimize the microsurgical technique of the choledochus anastomosis and fibrin glue adhesion by long-term experiments with rats. By comparing clinical, laboratory-chemical, radiological and histological characteristics of 5 test-groups with a control group 6 months after performing the operations the microsurgical interrupted suture of the obliquely interrupted choledochus showed the best results. Because there is a tendency of post operative stenosis the fibrin glue adhesion could not be recommended.

Anastomosis, Surgical↗
PubMedDate not supplied

Educational approach on stroke training in Europe.

According to the European Stroke Initiative (EUSI), stroke care is best delivered within a stroke unit by a specialized multidisciplinary stroke team led by stroke specialists. At present, there is no guideline or consensus regarding training requirements or clinical standards that stroke specialists should achieve. It is envisaged that stroke specialists in training would need to acquire adequate knowledge and competency across three major areas of stroke care: acute stroke, stroke rehabilitation, and stroke prevention. With an EUSI document, the European Association of Young Neurologists and Trainees Stroke Subspeciality Group aims to promote discussion on the many aspects of stroke training and the requirements to be a stroke specialist in the European community. The ultimate purpose is to agree on common standards to promote good clinical care and effective stroke prevention across Europe. In the future, this may be translated into better patient outcome and a reduction in the global burden of this condition.

Clinical Competence↗
PubMedDate not supplied

Central and paracentral visual field defects and driving abilities.

The effect of central and paracentral visual field defects on driving abilities has until now received little attention. To date studies and surveys have concentrated on visual acuity and peripheral field loss. Here we summarise for the first time those diseases causing central visual field defects likely to be associated with binocular visual acuity adequate for driving.

Automobile Driver Examination↗