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J Fröhlich

Publications and source records attributed to J Fröhlich.

At least 19 recordsLinked to original sources
PubMed2004

[Prolactinoma of the sphenoid sinus. Case report and literature review].

In this case study, we report on a patient complaining of headache who, after CT and MRI, was found to have a neoplasia of the left sphenoid sinus. After a transnasal biopsy and histological examination, a prolactinoma was diagnosed. Based on this case, we discuss important aspects of tumor biology, diagnostic procedures, histology as well as differential diagnosis. Prolactinoma has to be considered as a differential diagnose in all sphenoid sinus neoplasias with close contact to the pituitary gland.

Diagnosis, Differential↗
PubMed2002

[Child is inattentive, cannot sit still, disturbs the classroom. Is it really a hyperkinetic disorder?].

The clarification of attention-deficit/hyperactivity disorder (ADHD) requires an unequivocal categorization of the diagnostic criteria and a differentiation of the condition from normal variations and other disorder patterns. The ICD-10 criteria comprise the main symptoms inattention, hyperactivity and impulsivity. In kindergarten and preschool children, hyperactivity predominates, while in schoolchildren poor attention and cognitive impulsivity tend to be to the fore. In adolescence, aggressiveness and dissocial behavior coupled with drug abuse become central. In adulthood, ADHD is associated in particular with a tendency towards a lower social status and more frequent delinquency. Establishment of the diagnosis of ADHD requires information from the person to whom the individual relates. In this connection, exploration schemas, check lists and questionnaires are often very helpful. With regard to the differential diagnosis, mental disturbances due to physical causes (e.g. hearing disorders, epilepsy, etc.) must be excluded. Consideration must also be given in particular to comorbidities--found in up to two-thirds of cases--in which disordered social behavior, affective disorders and anxiety disturbances dominate.

Adolescent↗
PubMed2001

Arterial first pass gadolinium-CM dynamics as a function of several intravenous saline flush and Gd volumes.

This study was performed to evaluate the dynamics of an arterial first pass gadolinium (Gd) contrast medium (CM) bolus at the descending aorta (DAo), depending on various saline flush and Gd volumes. Using an ultra-fast two- dimensional GE-sequence (Siemens Vision, 1.5-T), 200 sequential cross-sectional images of the addressed vessel (1 slice/s) were obtained. Several saline flush volumes (15 mL, 30 mL, and 60 mL) were applied following the administration of 10 mL Gd (single dose) to a group of 4 normal volunteers (body weight 50-55 kg) using a mechanical MR injector (injection rate = 3.0 mL/s). Additionally, when performing a second test series, the saline volume remained constant, while the Gd volumes were varied from half doses to triple doses (5, 10, 20, and 30 mL Gd were given to every volunteer of the group). The signal intensity versus time (SI/T) curve at a measured region of interest (ROI) within the DAo was calculated. The bolus arrival time (BAT), the maximal signal-to-noise ratio (SNR(max)), the bolus time length (BL; 75% and 80% maximum intensity duration), the slope of the SI/T curve, and the areas below the SI/T curve for both the 80% and 75% maximum intensity duration level (INT(80%) and INT(75%)) were calculated. The increase of saline flush volume from 30 to 60 mL caused significant bolus lengthening of approximately 50% (mean BL = 9.5 s, 10.3 s, and 15.4 s for 15 mL, 30 mL, and 60 mL saline flush volumes, respectively, measured as SI/T duration at the 75% SNR(max) level). Using saline flush volumes equal to or higher than 30 mL increased the slope of the SI/T curve. A continuous increase of INT(75%/80%) by using higher saline flush volumes was found. Different saline and Gd volumes did not affect the SNR(max) and the BAT. Only the low dose (0.05 mmol/kg Gd) showed a 17%-21.6% significantly lower SNR(max). The BL and the INT increased mainly by enlarging of applied Gd volume from single to double dose (BL(75%) and INT(75%) were 9.6 s and 1305, 12.3 s and 2121, 38.5 s and 6181, 37.8 s and 6613 for 5, 10, 20, and 30 mL applied Gd volume, respectively). The arterial bolus length benefits from increasing Gd and saline flush volumes due to increased venous bolus length and wash out effects of Gd within the injection site of the vein. Doses larger than a single dose are not needed to increase the SNR in contrast-enhanced magnetic resonance angiography images of the thoracic aorta.

Aorta, Thoracic↗
PubMed2001

Dynamic patterns of USPIO enhancement can be observed in macrophages after ischemic brain damage.

Cells of the mononuclear phagocytotic system (MPS) are often found near to or within ischemic tissue and can potentially aggravate cellular damage. Hence, visualization of those cells would allow demarcation of putatively affected from intact tissue. Experimental MRI studies have shown that ultrasmall particles of dextran-coated iron oxide (USPIO) are internalized into cells of the MPS. To test if this cell tagging method may be also applied to cerebral infarction, USPIOs were administered to Fisher rats 5.5 h after permanent occlusion of the middle cerebral artery (pMCAO). During the first 2 days USPIO were preferentially found in patches within the lesion and in surrounding areas. On day 4, USPIOs expanded within the core of the lesion. On day 7 they were found predominantly within the boundary area. Histological analysis showed large populations of macrophages containing iron particles in the infarcted tissue. We conclude, therefore, that it is possible to monitor MPS activity after focal cerebral ischemia using USPIOs.

Animals↗
PubMed2000

New techniques for isolation of single prokaryotic cells.

Since the 1960s, several new attempts have been made to improve the management of single prokaryotic cells using micromanipulator techniques. In order to facilitate the isolation of pure cultures we have recently developed an improved micromanipulation method for routine work. With the aid of this method single prokaryotic cells can be picked out of a mixed community under direct visual control. The isolated aerobic or anaerobic cells can be grown in pure culture or can be subjected to single cell PCR. Other powerful and completely new approaches are the applications of laser micromanipulation systems, such as optical tweezers or laser microdissection techniques. Of the latter two methods only optical tweezers have been successfully applied to cloning prokaryotic cells.

Bacteria↗
PubMed1999

Enantiomeric resolution of galanthamine and related drugs used in anti-Alzheimer therapy by means of capillary zone electrophoresis employing derivatized cyclodextrin selectors.

An analytical assay is presented for the determination of the enantiomeric composition of galanthamine and related synthetic and natural compounds. (-)-Galanthamine is isolated from Galanthus nivalis and is used in this optical pure form in the therapy of Alzheimer's disease. Recent efforts for a total synthesis of unichiral (-)-galanthamine is connected with the need for a fast and reliable assay for the determination of the optical purity of the end product, as well as for optimizing and controlling the final steps in total synthesis particularly the asymmetric transformation of narwedine. In this paper the enantiomeric resolution of these compounds is reported employing a capillary electrophoretic system with beta-cyclodextrin derived chiral selectors. With the proposed system a number of galanthamine and narwedine derived analogous compounds could be separated, including 1-bromo- and N-alkyl-substituted compounds.

Alzheimer Disease↗
PubMed1999

Ethidium bromide: a fast fluorescent staining procedure for the detection of symbiotic partnership of flagellates and prokaryotes.

The hindgut of 'lower' termites harbors a dense population of flagellates and bacteria. The flagellates possess ecto- and endosymbiotic prokaryotes. Most of them are hardly visible in the phase contrast microscope. Staining with the DNA-intercalating agent ethidium bromide visualizes the nuclei of the flagellates as well as the ecto- and endosymbiotic bacteria as red objects. Furthermore, it is possible to distinguish between endosymbiotic methanogens and other bacteria. Following UV excitation, the blue-green autofluorescence of the methanogenic bacteria eclipses the red fluorescence light of the intercalated ethidium bromide. The dye facilitates the observation of symbiotic bacteria and helps identify the number, shape, localization, and dividing status of the nuclei. Thus, it is a powerful tool for the examination of microorganisms in complex habitats, which are rich in strongly autofluorescent material, like wood.

Animals↗
PubMed1999

Rapid isolation of single microbial cells from mixed natural and laboratory populations with the aid of a micromanipulator.

In order to facilitate the isolation of pure cultures from natural habitats we have developed a method for the isolation of single microbial cell clones from a mixed population, e.g. the flora of the termite gut, with the aid of a modern micromanipulator. The separated single prokaryotic or eukaryotic cells were grown after transfer in culture media or they were used for single cell PCR. The micromanipulator was also applied for the removal of nuclei from protozoa, of which the SSU rDNA was directly amplified.

Animals↗
PubMed1999

Isolation of Desulfovibrio intestinalis sp. nov. from the hindgut' of the lower termite Mastotermes darwiniensis.

A Gram-negative, anaerobic sulfate-reducing bacterium was isolated from hindgut contents of the lower termite Mastotermes darwiniensis Froggatt (strain KMS2). Strain KMS2 is motile by a single polar flagellum. The isolate possesses desulfoviridin and catalase activity. The G+C content of its DNA is in the range of 54.5-55.5 mol% (strain KMS2). It respires hydrogen and different low molecular weight organic compounds in the presence of sulfate, thiosulfate, and sulfite, and also oxygen. The isolated strain ferments pyruvate. Fastest growth with a doubling time of 12.5 h was obtained at 37 degrees C and not at 28 degrees C, the temperature at which the termites were grown. The isolate showed a 16S rDNA sequence homology of 95.9% to Desulfovibrio desulfuricans ATCC 27774 and a DNA-DNA homology of 44.6% to D. desulfuricans Essex 6 (type strain). Based on its biochemical properties and 16S rDNA sequence, the isolate was assigned to a new species named Desulfovibrio intestinalis.

Animals↗
PubMed1998

Unusual explanation for the death of a car passenger.

After collision of a car with the left rearside against a steel mast the 19-year-old front seat passenger was found comatose on the seat. CT imaging showed a depression fracture parietal on the left with an intracerebral haemorrhage on the opposite side. The cause of the injury was unknown to the surgeons at the time of operation. Despite neurosurgical intervention the patient died 24 h after the accident. The post-mortem showed an additional depression fracture at the base of the skull in the right temporal region arousing suspicion of an impalement injury. Only inspection of the car by the forensic pathologists revealed the gas pressure telescopic shock absorber to be the cause of the head injury.

Accidents, Traffic↗
PubMed1997

[The suicide conference. An instrument for support of involved teams after inpatient suicides].

This is a report on the authors' experience over two years in developing a new way to deal with patient suicides in a District Psychiatric Hospital. The main aim of the Suicide Counselling Session is to help the involved hospital ward teams to overcome the strain, doubt and psychological burden often caused by the suicide of a patient. The authors describe the institutional conditions and setting in which a Suicide Counselling Session takes place. The method is characterised by a special attitude and the ideas of "Reflecting Team" to bring the involved stress factors into the open.

Adaptation, Psychological↗
PubMed1996

Stability of nonrelativistic quantum mechanical matter coupled to the (ultraviolet cutoff) radiation field.

We announce a proof of H-stability for the quantized radiation field, with ultraviolet cutoff, coupled to arbitrarily many non-relativistic quantized electrons and static nuclei. Our result holds for arbitrary atomic numbers and fine structure constant. We also announce bounds for the energy of many electrons and nuclei in a classical vector potential and for the eigenvalue sum of a one-electron Pauli Hamiltonian with magnetic field.

Journal Article↗
PubMed1996

Cholesterol and atherosclerotic vascular disease: from science to public health policy.

Advances in our understanding of the pathology, epidemiology, genetics (particularly the recent research on transgenic animals) and the results of randomized prospective clinical trials all contribute to the formation of public health policy on serum cholesterol and other lipids. This article outlines the scientific background of these policies. There remains little doubt that dyslipidemia contributes to the development of coronary atherosclerosis and that effective treatment can prevent or retard its development.

Animals↗